AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 229 PM MDT THU APR 29 2004 .SHORT TERM... (TONIGHT AND FRIDAY) ...POTENTIAL FOR SOME WELL NEEDED PRECIPITATION TONIGHT AND FRIDAY... CURRENTLY...WATER VAPOR IMAGERY AND RUC MODEL UPPER AIR ANALYSES SHOWING THE LOW PRESSURE SYSTEM AND ULJ OVER THE GREAT BASIN EARLY THIS AFTERNOON. THE SHALLOW COLD FRONT THAT RACED THROUGH ERN CO EARLIER THIS MORNING WAS WELL SOUTH AND IS ONLY UP TO AROUND 9K FT MSL WITH LA VETA PASS HAVING AN EAST WIND AND COOLER TEMPERATURES IN SERN CO AND THE SAN LUIS VALLEY HAVING GUSTY S-SW WINDS AND MILD TEMPERATURES. SATELLITE AND RADAR STARTING TO SHOW CONVECTIVE PRECIPITATION BREAKING OUT IN THE WRN 1/2 OF CO WITH SHRA/SHSN ALREADY OVER THE UPPER AR RIVER VALLEY. THE 12Z/29 MESO-ETA(ETA) FORECAST AT 18Z/29 IS DOING PRETTY WELL GIVEN CURRENT SATELLITE AND SFC OBS TRENDS. TNGT...STILL VERY BIG CHALLENGES IN TERMS OF HOW MUCH SNOW AND WHERE WILL IT FALL GIVEN THE PROJECTED ORIENTATION...AND EVOLUTION...OF THE LOW WHEN IT TRACKS ALONG CO/NM BORDER. INITIALLY THIS EVENING... SNOW LEVELS SHOULD BE AROUND 9K-10K FT MSL AND THEN LOWER TO AROUND 7K FT MSL...WITH THE MORE INTENSE PRECIPITATION CORES DROPPING THE SNOW LEVEL ANOTHER 1K-2K FT DUE TO DIABATIC/EVAPORATIVE . GIVEN THE TRACK AND EVOLUTION OF THIS POTENTIAL STORM SYSTEM...THIS PUTS MUCH OF S CNTRL/SERN CO IN THE SYSTEM'S MOST "INTENSE" UPWARD VERTICAL MOTION. AS THE SYSTEM NEARS...KINEMATIC ANALYSES ARE SHOWING IMPLIED UPWARD VERTICAL MOTION "BOMBING OUT" ACROSS SRN CO BETWEEN 03Z/30 THROUGH 18Z/30. GIVEN THIS PATTERN...I AM ANTICIPATING THE RADAR TO "LIGHT UP" IN TERMS OF PRECIPITATION FROM THE SRN FOOTHILLS...ALONG I-25...AND WWD TOWARDS THE CONTDVD THIS EVE. THE 12Z/29 ETA AND GFS BOTH HAVE SIMILAR QPF MAX CORE TRACKS FROM THE SRN FOOTHILLS...ACROSS THE SANGRE DE CRISTO AND WET MTS...NEAR TELLER COUNTY AND THEN BACK TOWARDS THE UPPER AR RIVER VALLEY AND THE COLLEGIATE/MOSQUITO MT RANGES FOR THE 12 HOUR PERIOD TONIGHT. THE ETA HAS THE MOST WITH NEAR 1.14 INCHES AROUND SERN PORTION OF THE WET MTS AND ANOTHER 1.00 INCH "BULLSEYE" AROUND SALIDA AND BUENA VISTA TNGT. GIVEN THE VERTICAL THERMAL PROFILE AND POTENTIAL VERTICAL ASCENT INTENSITY... MOST OF THE CENTRAL AND SERN CO MTS WILL LIKELY SEE 10+ INCHES OF HIGH WATER CONTENT SNOWFALL ENDING BY FRI AFTN. AS USUALLY...THE REAL CHALLENGE AREA(S) WILL BE AT THE 5K-7K FT MSL ELEVATIONS ALONG THE I-25 CORRIDOR. CURRENTLY...WE HAVE ABOUT 3-8 INCHES FORECAST FOR NRN EL PASO COUNTY. THROUGH TNGT...AND EVEN ON FRI...THERE WILL BE VARIOUS UPSLOPE AND DOWNSLOPE WIND DIRECTIONS AS THE SYSTEM APPROACHES. HOWEVER...THE SYNOPTIC SCALE ASCENT MAY COMPENSATE FOR THE LACK OF UPSLOPE FLOW SOMETIMES. DEPENDING ON THE PRECIPITATION'S INTENSITY...5K-7K FT MSL ELEVATIONS COULD SEE A MIX OF RAIN AND SNOW WITH MORE SNOW ACCUMULATIONS AROUND 6K-7K FT MSL LATER TNGT. GIVEN THE TRACK AND EVOLUTION OF THE STORM...EL PASO COUNTY(NRN AND SRN) COULD GO EITHER WAY DURING THIS EVENT. FOR THE SWRN CO MTS...THE COMBINATION OF STORM DYNAMICS AND A FAVORED OROGRAPHIC INFLOW SHOULD HELP PRODUCE 4-8 INCHES OF SNOW TONIGHT...BUT THERE IS A HINT OF THE "DRY" SLOT WORKING INTO THAT AREA LATE TNGT INTO FRI AM. THE FAR SERN CO PLAINS SHOULD SEE ALL LIQUID. FINALLY...FOR THIS EVENING I HAVE ADDED SOME THUNDER OUT AROUND THE CONTDVD GIVEN THE STEEP LAPSE RATE THAT WILL STILL BE IN THAT AREA. FRI...THERE ARE SOME DIFFERENCES BETWEEN THE ETA AND GFS AS THE WEATHER SYSTEM MOVES ALONG CO/NM BORDER. THE ETA TENDS TO WEAKEN THE SYSTEM...WHILE THE GFS KEEPS IT MORE "CRANKED UP." THIS CAN BE SEEN IN THE QPF TRACKS WITH THE GFS HAVING A MAX QPF CORE FROM TELLER COUNTY THROUGH THE PALMER DVD AND THIS WOULD BE IN THE GFS'S DEPICTION OF THE DEFORMATION ZONE PRECIPITATION AND SEEN IN TROWAL ANALYSES. MESO-ETA(ETA) DOES HAVE A H7-H6 LAYER TROWAL STRUCTURE FROM NERN CO BACK TOWARDS COLORADO SPRINGS AND THE SRN FOOTHILLS. RAIN AND SNOW SHOULD CONTINUE TO BE FALLING WITH THE SNOW LEVEL AROUND 6K-7K FT MSL. IF THE CLOUD COVER AND PRECIPITATION CONTINUE...THEN THERE SHOULD BE SMALL DIURNAL TEMPERATURE SWINGS. AS FOR HEADLINES...WILL GO WITH A WINTER WEATHER ADVISORY FOR THE SWRN CO MTS TNGT-FRI FOR 4-8 INCHES. WINTER STORM WARNING FOR THE COLLEGIATE/MOSQUITO MT RANGES...TELLER COUNTY...WET MTS...AND SANGRE DE CRISTO MTS TNGT-FRI FOR 10-20+ INCHES. WINTER WEATHER ADVISORY THE THE MID AND UPPER AR RIVER VALLEYS FOR TNGT-FRI FOR 3-8 INCHES. A WINTER WEATHER ADVISORY FOR NRN EL PASO COUNTY FOR TNGT-FRI FOR 3-8 INCHES.[METZE] .LONG TERM... (FRIDAY NIGHT THROUGH THURSDAY) ...QUIET WEATHER AFTER FRIDAY NIGHT... .FRIDAY NIGHT...GFS AND ETA SHOWING SOME DIFFERENCES IN THE SOLUTION FRIDAY NIGHT...WITH THE ETA KEEPING MORE ENERGY TO THE SOUTHWEST OVERNIGHT. THE ETA SOLUTION WOULD TEND TO KEEP MORE PRECIPITATION OVERNIGHT FRIDAY OVER MUCH OF THE AREA...WHILE THE GFS WOULD TEND TO END MOST OF PRECIPITATION BY MIDNIGHT. I INCREASED THE POPS TO HIGH CHANCE OVER THE PLAINS AND EASTERN MOUNTAINS FRIDAY EVENING... THEN KEPT SMALL POPS OVERNIGHT. EVENING IF THE PRECIPITATION LINGERS PAST MIDNIGHT AS IN THE ETA...IT WILL BE LIGHT. .SATURDAY...A WEAK DISTURBANCE MOVES IN FROM THE NORTH DURING THE AFTERNOON. THE ATMOSPHERE WILL BE DRY. THERE WILL BE ENOUGH INSTABILITY AND MOISTURE TO GET SOME SHOWERS OVER THE PIKES PEAK REGION AND CENTRAL MOUNTAINS. ANY SHOWERS SHOULD END BY MID EVENING...WITH DECREASING CLOUDS. .SUNDAY AND MONDAY...NORTH TO NORTHWEST FLOW ALOFT CONTINUES OVER THE REGION WITH RIDGE TO THE WEST. A WEAK SURGE MAY COOL TEMPERATURES A LITTLE SUNDAY NIGHT AND MONDAY. 700MB TEMPERATURES CONTINUE TO WARM WITH GENERALLY DRY WEATHER. .TUESDAY THROUGH THURSDAY...RIDGE WILL MOVE OVER THE REGION. GFS HAS A SURGE FLIRTING WITH THE NORTHEAST TIP OF COLORADO...BUT THIS IS FAR INTO THE FUTURE. CONTINUED DRY WEATHER WITH WARM TEMPERATURES. --PGW-- && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING...COLLEGIATE/MOSQUITO MT RANGES(058/060/061/ 063)...TELLER COUNTY(081/082)...WET MTS(079/080)...AND SANGRE DE CRISTO MTS(072>075) FROM 9PM TNGT TO 5PM FRI. WINTER WEATHER ADVISORY...MID AND UPPER AR RIVER VALLEYS(059/062/077/078)...ERN SAN JUAN/LA GARITA MTS(068/066)... AND NRN EL PASO COUNTY(084) FROM 9PM TNGT TO 5PM FRI. && $$ co AREA FORECAST DISCUSSION...CORRECTED ADVISORY ZONE 39 NOT 38 NATIONAL WEATHER SERVICE DENVER CO 310 PM MDT THU APR 29 2004 .SHORT TERM...EXACTLY ONE WEEK AGO WE FACED A SOMEWHAT SIMILAR SITUATION AND THIS ONE IS JUST AS TRICKY. RIGHT NOW CLOSED UPPER LEVEL LOW IS OVER WESTERN UTAH MOVING SSE AND SHOULD END UP NEAR THE 4-CORNERS BY 12Z FRIDAY. A JET STREAK AHEAD OF THIS IS PROVIDING THE APPARENT FORCING FOR DEVELOPMENT OF THUNDERSTORMS OVER THE MOUNTAINS THIS AFTERNOON AND SOME OF THESE SHOWERS COULD DRIFT INTO THE FOOTHILLS OVER THE NEXT FEW HOURS...OTHERWISE CONTINUED LIGHT DRIZZLE OR VERY LIGHT SNOW INTO THE EVENING. A WELL-DEFINED SHORTWAVE IS ROTATING AROUND THE BASE OF THE UPPER LEVEL LOW ACROSS AZ AT THIS TIME AND THIS WILL SWING OVER THE FORECAST AREA TONIGHT PROVIDING THE MAIN UPPER LEVEL SUPPORT. IN LAST WEEK'S STORM THERE WAS AN INCREDIBLY SHARP NORTHERN CUTOFF TO THE SNOW THAT WAS APPARENTLY ASSOCIATED WITH A SOUTHWARD DIP TO A SHARP DEFORMATION ZONE ALOFT. A SIMILAR FEATURE EXISTS WITH THIS EVENT BUT ALL SIGNS INDICATE IT SHOULD BE LOCATED NEAR THE WY/CO BORDER THIS TIME. LIKE LAST WEEK'S EVENT THOUGH THE STRONGEST FORCING WILL BE OVER THE SOUTHERN HALF OF THE CWA AND THIS IS WHERE THE CURRENT WINTER WEATHER ADVISORIES ARE FOUND. THE 700 MB CIRCULATION ASSOCIATED WITH THIS APPROACHING STORM IS NOT AS ORGANIZED AS ONE WOULD LIKE TO SEE FOR A REALLY SIGNIFICANT EVENT AND THIS REMAINS ONE AREA OF CONCERN FOR HOW MUCH SNOW AND PRECIP WE WILL SEE ALONG THE FOOTHILLS AND URBAN CORRIDOR. COLD AIR IS IN PLACE AND THE PRECIP IS EXPECTED TO BE MAINLY SNOW ONCE THE RATE PICKS UP LATER TONIGHT. THE CURRENT FORECAST HAS THE IDEA OF HEAVIEST PRECIP IN THE SOUTHERN HALF OF THE FORECAST AREA AND MAIN CHANGES WILL BE TO ADD ZONE 39 AND ZONE 46 TO THE WINTER WEATHER ADVISORY. CONFIDENCE FOR ZONE 39 IS HIGHEST IN THE JEFFERSON COUNTY REGION. SOUTHERN PORTIONS OF ZONE 40 COULD SEE ADVISORY CRITERIA BUT DECISION TO KEEP ZONE 40 JUST BELOW ADVISORY. SOUTHERN PART OF ZONE 35 COULD BE IN ADVISORY CRITERIA BUT THE AMOUNTS FOR THIS ARE HIGHER THEN THE PLAINS AND AT THIS TIME WILL JUST HAVE ZONE 36 IN THE ADVISORY. LATEST ETA AND MM5 LOCAL MODEL RUNS AND RUC RUN OUT THROUGH FRIDAY ARE REASONABLY CONSISTENT WITH AMOUNT AND DISTRIBUTION OF PRECIPITATION. ONE AREA WHERE AMOUNTS LOOK A LITTLE HIGH IS FAR NE AREA WHERE 18Z ETA HAS MORE THAN 0.5" WATER BY 18Z FRIDAY. WILL HOLD OFF ON PRECIP IN THE FAR NORTHEAST TILL VERY LATE TONIGHT. THE MAIN PERIOD OF FORCING AND PRECIPITATION FOR MOST OF THE AREA LOOKS TO BE FROM 06Z TO 18Z. AFTER 18Z PRECIP COULD CONTINUE BUT WILL LIKELY BE SOUTH AND EAST OF DENVER...MUCH LIKE LAST FRIDAY AFTER 18Z...UNLESS THE UPPER LOW HOLDS TOGETHER BETTER THEN INDICATED IN THE CURRENT MODELS. .LONG TERM DISCUSSION...PRECIPITATION SHOULD BE ON THE DECREASE FRIDAY NIGHT AS UPPER TROUGH TRACKS EAST. UPSLOPE FLOW WEAKENS AS SURFACE WINDS BECOME NORTHWEST. THERE STILL REMAINS WEAK DYNAMICS OVER AREA...AS NOTED BY DIV-Q PROGS AND ETA KEEPS SOME LIGHT QPF OVER CWA THROUGH 12Z SATURDAY. AIRMASS SHOULD BEGIN TO DRY OUT LATE SATURDAY AS UPPER RIDGE BUILDS TO THE WEST. STILL...BOUNDARY LAYER HUMIDITY PROGS KEEP SOME MOISTURE OVER THE HIGHER TERRAIN. WILL KEEP SOME LOW POPS THROUGH THE DAY...BUT DROP THEM FOR SATURDAY NIGHT. FOR SUNDAY AND MONDAY...THE RIDGE WILL CONTINUE TO BUILD WEST OF THE AREA...KEEPING COLORADO UNDER NORTHWEST FLOW ALOFT. THE AVN HINTS AT A WEAK WAVE MOVING THROUGH THE FLOW MONDAY...THOUGH DOES NOT GENERATE PRECIPITATION. WILL KEEP THINGS DRY...BUT MAY SHAVE A FEW DEGREES OFF OF THE HIGHS. FROM TUESDAY THROUGH THURSDAY...RIDGE AXIS WILL BE OVER THE AREA WITH A VERY WARM AND DRY AIRMASS ENTRENCHED OVER THE REGION. HIGHS OVER THE PLAINS COULD EXCEED 80 DEGREES...WHICH IS ABOVE THE LONG RANGE GUIDANCE. WITH THE WARM AND DRY AIRMASS...SOME AREAS COULD SEE SINGLE DIGIT HUMIDITY READINGS BY MID WEEK. && .WINTER WEATHER ADVISORY FROM 6 PM TONIGHT UNTIL 6 PM FRIDAY FOR THE MOUNTAINS AND FOOTHILLS SOUTH OF INTERSTATE 70...SOUTH PARK AND THE PALMER DIVIDE...AND EASTERN BOULDER AND JEFFERSON COUNIES...ZONES 34..36..37..39..41..AND 46. $$ SZOKE/LESZCYNSKI co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 855 PM EDT THU APR 29 2004 .DISCUSSION... THE 00 UTC SURFACE ANALYSIS SHOWS SOUTHEAST FLOW OVER MOST OF THE SOUTHEAST U.S. WITH A STRONG HIGH PRESSURE CENTER OF THE NORTH CAROLINA COAST. A MOISTURE GRADIENT IS ORIENTED FROM SOUTHEAST TO NORTHWEST AND ROUGHLY BISECTS OUR FORECAST AREA. MOST OF THE RAIN THAT IS OCCURRING IS ALONG AND WEST OF THIS BOUNDARY WHERE THE AIRMASS IS MORE MOIST AND UNSTABLE. WATER VAPOR IMAGERY AND UPPER AIR OBS SHOW A POTENT LITTLE SHORT WAVE TROUGH MOVING NORTHEAST AT 40 MPH INTO SOUTHWEST PORTIONS OF TENNESSEE. THERE IS ENOUGH Q-G FORCING...DEEP LAYER MOISTURE...AND INSTABILITY EXTENDING DOWN FROM THIS SHORT WAVE TO DRIVE THE DEEP CONVECTION OVER WESTERN SECTIONS OF OUR FORECAST AREA. A FEW OF THE STORMS WEST OF OUR AREA HAVE HAD SUPERCELL CHARACTERISTICS ON RADAR. THE 00 UTC KTLH SOUNDING HAS SHOWN A MARKED INCREASE IN MOISTURE AND INSTABILITY...AND COULD SUPPORT THUNDERSTORMS IF THERE IS SUFFICIENT FORCING. THE CAPE IS NOT VERY HIGH THOUGH AND DEEP LAYER VERTICAL WIND SHEAR IS LACKING...SO I DON'T THINK THERE WILL BE MUCH OF A SEVERE WEATHER THREAT. ANY SEVERE WEATHER WOULD BE ISOLATED AND PROBABLY LIMITED TO OUR WESTERN COUNTIES. FOR THE EVENING UPDATE I WILL PROBABLY ADJUST THE POPS UP A LITTLE IN THE WEST. I PLAN TO LOWER THE WINDS AND SEAS ON THE CWF UPDATE BASED ON RECENT TRENDS AND THE LATEST RUC. && .PREV DISCUSSION... 135 PM EDT THU APR 29 2004 .SYNOPSIS...SURFACE ANALYSIS HAS SE-S FLOW OVER THE CWA WITH THE HIGH PRESSURE RIDGE TO THE EAST. MOISTURE IS GRADUALLY INCREASE OVER THE CWA WITH DEWPOINTS IN THE UPPER 50S TO 60S. MESOETA & IR/VSBY SATELLITE IMAGERY...HAS A GOOD DEPICTION OF THE UPPER SHORTWAVE OVER THE GULF DEVELOPING ISOLATED SHOWERS & TSTMS. FLOW WILL TAKE THIS ENERGY OVER THE CWA LATER TODAY & TONIGHT. WILL KEEP 30-40% TONIGHT WITH THIS FEATURE. && .SHORT TERM...(TONIGHT THROUGH SATURDAY). GFS CONTINUES TO OVER DEVELOP OMEGA-BOMB IN THE GULF...ETA SOLUTION APPEARS TO HANDLE BETTER. CHANCE POP OVERNIGHT WITH THIS SHORTWAVE ENERGY MOVING NE OVER CWA. THEN FRIDAY & SATURDAY ARE TRANSITION DAYS WITH SOME SHORTWAVE ENERGY MOVING THROUGH THE SOUTHERN STREAM & WILL KEEP 30-40% POP IN THE FORECAST...& MAINLY IN THE AFTERNOON & EVENINGS WITH HEATING HELPING TO DESTABILIZE THE ATMOSPHERE. && .LONG TERM...(SUNDAY THROUGH WEDNESDAY). ON SUNDAY THE COLD FRONT APPROACHES & RAIN & TSTMS CHANCE WILL BE 40-50%...COULD GO TO LIKELY AS WE GET CLOSER TO SUNDAY WITH ANY ADDITIONAL ENERGY. COLD FRONT SHOULD DRIFT THROUGH THE CWA BY MONDAY MORNING...BUT GFS HAS SHOWN TO BE TOO FAST & WITH IT SHOWING SURFACE LOW DEVELOPING IN THE GULF ALSO A BIT SUSPECT. WILL KEEP SOME POPS INTO MONDAY TO HEDGE ON TIMING OF COLD FRONT & NW FLOW. SEVERE THREAT REMAINS LOW AT THIS TIME. && .MARINE...WINDS & SEAS CAME UP A BIT EARLY IN THE OFFSHORE WATERS TODAY & SCA NOW IN EFFECT. THIS SHOULD REMAIN UP WITH THE GOOD EAST FLOW...WHILE SCEC OVER THE NEAR SHORE INTO FRIDAY. THE GRADIENT RELAXES A BIT ON FRIDAY SO SCEC WILL PROBABLY WORK ALL AREAS. THIS SHOULD BE THE CASE THROUGH SUNDAY...UNTIL THE COLD FRONT NEARS THE CWA & BEHIND THE FRONT ON MONDAY. && .FIRE WEATHER...RH LEVELS REMAIN UP UNTIL TUESDAY NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... TLH 63 81 64 81 / 40 40 30 30 PFN 65 80 67 80 / 40 30 30 30 DHN 63 81 65 80 / 40 30 30 30 ABY 63 81 64 80 / 40 40 30 30 VLD 63 80 65 81 / 40 40 30 30 CTY 65 82 66 83 / 40 40 30 30 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. && $$ CURRENT DISCUSSION...FOURNIER PREVIOUS DISCUSSION...MCT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 330 PM CDT THU APR 29 2004 .DISCUSSION... MAIN FORECAST DIFFICULTIES WILL CONTINUE TO BE PRECIPITATION CHANCES TONIGHT THROUGH FRIDAY NIGHT. FRONTAL BOUNDARY HAS NOW PUSHED SOUTH OF DSM AND IS VERY SLOWLY MOVING SOUTH. MODELS DID NOT HANDLE THE MOVEMENT TO WELL EARLIER AS THE FRONTAL MOVEMENT WAS FASTER THAN EXPECTED. BOTH ETA AND AVN WILL BE TOO FAR N BY 00Z. MODELS DID DO A GOOD JOB FORECAST ONLY WEAK INSTABILITY TODAY. LATEST LAPS/RUC SOUNDINGS SHOWING CAPPED WEAK INSTABILITY OVER CENTRAL AREAS WITH WEAK INSTABILITY SE. LATEST SAT PICS SHOW SOME ENHANCED CU JUST N OF SFC BOUNDARY WITH CAPPED WAVE CLOUDS TO THE NORTH. AT THIS TIME IT DOES NOT LOOK LIKE A WHOLE LOT...IF ANYTHING WILL DEVELOP ALONG THE FRONT THIS AFTN OR EVENING. NONETHELESS WILL LEAVE LOW CHANCE POPS IN WITH BOUNDARY IN AREA. SHORT WAVE TROUGH TO OUR S ENDED UP A BIT FURTHER SSE THAN EXPECTED WITH NO PCPN MAKING IT INTO THE SE CWA THUS FAR. DOES LOOK LIKE A FEW SHOWERS WILL BRUSH THE FAR SE THIS EVENING. THERE ARE FAIRLY SIGNIFICANT DIFFERENCES IN THE ETA AND AVN WITH RESPECT TO THE SHORT WAVE TROUGH THAT LIFTS NE TOWARD THE REGION ON FRIDAY. ETA HOLDS IT BACK AND WEAKENS IT WHILE AVN IS MORE PROGRESSIVE...AS IS THE GEM. IF AVN IS CORRECT...LOW LEVEL BOUNDARY WILL BE CLOSE ENOUGH THAT ISENTROPIC LIFT WOULD BRING A DECENT SWATH OF RAIN OVER THE SOUTHERN HALF OF THE CWA. MODELS INDICATE VERY WEAK ELEVATED INSTABILITY OVER THE SE FRIDAY WITH THIS LAYER STABILIZING FRIDAY NIGHT. WILL MAINTAIN AN AREA OF LIKELY POPS IN THE FAR SE AND TIGHTEN THE POP GRADIENT OVER THE CENTRAL ZONES. FOR NOW TAKING A BLEND OF THE MODELS. CONTINUES TO LOOK LIKE A SECONDARY SURGE OF COOLER AIR WILL MOVE INTO THE AREA FRIDAY NIGHT WITH UPPER TROUGH SETTING UP OVER THE GREAT LAKES AND UPPER MS RIVER VALLEY THIS WEEKEND. ALL THE MODELS ROTATE A SHORT WAVE THROUGH THE BACK SIDE OF THE TROUGH LATE SATURDAY AND EARLY SUNDAY. WITH ELEVATED COLD CORE.. INSTABILITY WILL BE SUCH THAT SHOWERS WILL BE POSSIBLE. NUDGED UP POPS A BIT THIS WEEKEND. BEYOND SUNDAY...MODEL TRENDS SIMILAR. DOES LOOK LIKE THE SFC RIDGE WILL BE OVER THE STATE SUNDAY NIGHT RESULTING IN COLD CONDITIONS...BUT ON MONDAY THE WARM AIR ADVECTION BEGINS. UPPER RIDGE WILL KEEP THINGS DRY THROUGH MID WEEK. MODELS DO INDICATE THE POSSIBILITY OF A BOUNDARY SLOWLY DROPPING SOUTH TOWARD IA BY WEDS. THIS MAY ENHANCE POP POTENTIAL IN THE NE TUES NIGHT THRU THURSDAY. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE && $$ JAW ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 850 PM MDT THU APR 29 2004 .DISCUSSION...MAIN ITEM OF CONCERN THIS EVENING IS THE CHANCE OF PRECIPITATION OVERNIGHT. LATEST GUIDANCE BACKS OFF ON RAINFALL OVERNIGHT WITH GFS AND RUC BEING THE MOST ASSERTIVE BY BRINGING PRECIP INTO SOUTHERN HALF OF THE AREA IN THE 09-12Z TIMEFRAME. THIS IS A LITTLE LATER THAN PREVIOUS RUN AND ALSO NOT AS WIDESPREAD. 00Z ETA SHOWS LIGHT RAIN FINALLY REACHING SOUTHERN PORTION OF FORECAST AREA BY 12Z. LARGE MCS OVER OKLAHOMA MAY BE ROBBING A BIT OF THE MOISTURE AND HAVING AN INFLUENCE ON ATMOSPHERE'S ABILITY TO PRODUCE DECENT RAINFALL ACROSS NORTHWEST KANSAS UNTIL LATE TONIGHT. LARGE LOBE OF ENERGY IS LIFTING NNE ACROSS COLORADO AND THIS WILL LIKELY CLIP OUR COLORADO COUNTIES AND KANSAS BORDER COUNTIES OVERNIGHT. AS A RESULT WILL KEEP THE LIKELY POPS IN THE SOUTHWEST HALF OF THE AREA BUT DROP POPS DOWN TO THE CHANCE CATEGORY TONIGHT. REMAINDER OF FORECAST OVERNIGHT IS IN GOOD SHAPE IN TERMS OF CLOUDS...WINDS. 00Z MODELS STILL SHOWING A SIGNIFICANT SHORTWAVE TO LIFT NORTHEAST ACROSS THE AREA DURING THE DAY FRIDAY AS UPPER LOW IN THE SOUTHWEST US LIFTS OUT. CURRENT FORECAST HAS THIS WELL IN HAND. $$ .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ DLF ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 945 PM CDT THU APR 29 2004 WL BE SENDING A GRIDS/ZONE FCST UPDATE FOR A FEW CHANGES TO TONIGHT. COLD FRONT HAS MADE A BIT MORE PROGRESS THAN EXPECTED THIS EVENING, BUT SHOULD SLOW DOWN GIVEN WEAK PRESSURE RISES BEHIND THE BOUNDARY. LOWERED MINS A FEW DEGREES OVER MNLY S-CNTRL KS, AND ESP HOURLY TEMPS. LOOKS LIKE CONVECTION CHANCES WILL WAIT FOR AN UPR JET STREAK/SHORTWAVE LIFTING OUT OF THE 4 CORNERS AREA LATE TONIGHT INTO FRIDAY MORNING. UNTIL THEN, ONLY SLIGHT CHANCES FOR VERY LIGHT RAIN SHOWERS ASSOCIATED WITH WEAK ISENTROPIC LIFT. CARRYING CHANCE OF SHOWERS/T-STORMS AFTER 08Z WITH PROBABILITIES INCREASING OVER SERN KS FRIDAY AM. ELEVATED INSTABILITY IS WEAKER COMPARED TO PREVIOUS MODEL RUNS, AND THEREFORE NOT EXPECTING SEVERE WX OVERNIGHT. JMC ------------------------------------------------------------------ 338 PM CDT THU APR 29 2004 .DISCUSSION... MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE THE POSITION OF THE FRONT AND HEAVY RAINFALL POTENTIAL DURING THE NEXT COUPLE OF DAYS. TONIGHT: LATEST VISIBLE IMAGERY SHOWING A WELL DEFINED COLD FRONT CONTINUING TO PLOW INTO CENTRAL KANSAS. THIS FRONT HAS ACTED TO PRODUCE LOTS OF LOW CLOUDS BEHIND IT. AHEAD OF THE FRONT, THINGS ARE TRYING TO SCOUR OUT ACROSS THE SOUTHWEST PART OF THE CWFA WHERE THE CAP APPEARS TO BE A LITTLE WEAKER. FURTHER EAST, THE CAP LOOKS TO BE RATHER STRONGER ACCORDING TO THE LATEST RUC SOUNDING. LATEST RUC ANALYSIS SHOW THIS FRONT PUSHING INTO SOUTH CENTRAL KANSAS THIS EVENING AND HANGING UP ALONG A LINE FROM NEAR ICT TO MARION. RIGHT NOW, I WOULD EXPECT SOME THUNDERSTORMS TO FIRE IN THE WEAK CAPPED AREAS OF NORTHWEST OK LATE THIS AFTERNOON WITH THE MEAN LEVEL FLOW SHIFTING THESE STORMS INTO SOUTH CENTRAL KANSAS AFTER 6 PM. SURFACE BASED CAPE VALUES COULD REACH 2000J/KG IF THINGS CLEAR OUT. HOWEVER, SHEAR VALUES ARE VERY MINIMAL WHICH MEANS THAT MOST OF THE STORMS WILL PROBABLY BE MULTICELLULAR WITH THE HAIL BEING THE MAIN THREAT. OVERNIGHT MORE THUNDERSTORMS WILL DEVELOP ACROSS SOUTH CENTRAL AND SOUTHEAST KANSAS WHERE DECENT ISENTROPIC LIFT WILL BE IN PLACE ESPECIALLY AROUND 305K. TOMORROW: THE MAIN QUESTION WILL BE THE POSITION OF THE FRONTAL BOUNDARY TOMORROW. THIS WILL BE PLAY A BIG ROLE IN THE TEMPERATURE DEPARTMENT. THE ETA APPEARS TO HAVE THIS FRONT TOO FAR NORTH, AFTER LOOKING AT THE LATEST RUC ANALYSIS. WE WILL KEEP THE FRONT SITUATED MAINLY ALONG AND NORTH OF A HUTCHINSON TO MARION LINE, BUT IT COULD DIVE SOUTH DURING THE COURSE OF THE DAY, DUE TO LOTS OF CONVECTION AROUND. HOWEVER, THIS COULD BE ALTERED IN LATER FORECASTS. NORTH OF THE FRONTAL BOUNDARY, TEMPERATURES WILL STRUGGLE TO GET OUT OF THE 40S DUE TO LOTS OF LOW CLOUDS IN PLACE. SOUTH OF THE BOUNDARY TEMPERATURES WILL REACH THE 60S AND 70S. MORE SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP DURING THE COURSE OF THE DAY, WITH MOST OF THE FOCUS EXPECTED ALONG AND SOUTH OF THE FRONTAL BOUNDARY. FRIDAY NIGHT-SATURDAY: WATER VAPOR LOOP CONTINUES TO SHOW MORE ENERGY DIVING BEHIND THE UPPER LEVEL WAVE IN THE ROCKIES. ONCE THIS WAVE, ROUNDS THE BASE OF THE TROF, IT WILL HELP SHIFT THE TROF EAST FRIDAY NIGHT AND SATURDAY. THE MODELS CONTINUE TO SLOW THINGS DOWN WITH THIS WAVE, WHICH HAS LED ME TO KEEP THE CHANCE OF RW- GOING INTO SATURDAY MORNING. THERE WILL BE SOME AID FROM THE RIGHT ENTRANCE REGION OF THE UPPER LEVEL JET ACROSS SOUTHEAST KANSAS WHICH RAISES A FLAG TO THE HEAVY RAIN POTENTIAL ACROSS SOUTHEAST KANSAS FRIDAY NIGHT. IT LOOKS LIKE THE MAIN SYNOPTIC SCALE LIFT WILL BE FRIDAY NIGHT. HOWEVER, THERE IS SOME QUESTION ON HOW FAST THE FRONT WILL MOVE THROUGH. IF THE FRONT HOLDS UP IT WE COULD END UP WITH SOME FLOODING POTENTIAL FOR SOUTHEAST KANSAS. RIGHT NOW, THE MODELS ARE FAIRLY PROGRESSIVE WITH THIS FRONT, AND SHIFT IT THROUGH SOUTHEAST KANSAS AFTER MIDNIGHT FRIDAY. WE WILL HOLD OFF ON A FLOOD WATCH FOR NOW, SINCE MOST OF THIS WILL BE DEPENDENT ON WHERE THE FRONT HANGS UP. SUNDAY-MONDAY: VERY UNSEASONABLE LIKE TEMPERATURES WILL BE IN STORE FOR THE AREA. IN FACT, MONDAY MORNING WE COULD BE FLIRTING WITH A FROST ADVISORY AS HIGH PRESSURE SETTLES IN PLACE. TUESDAY-THURSDAY: UPPER LEVEL RIDGE WILL BUILD OVER THE CWFA AND ALLOW FOR A NICE WARMUP FOR THE REST OF THE WEEK. TEMPERATURES SHOULD REBOUND TO THE 70S AND 80S WEDNESDAY AND THURSDAY AS THE LEE SIDE TROF SETS UP. && .PRELIMINARY POINT TEMPS/POPS... WICHITA 55 60 45 59 / 60 50 40 10 HUTCHINSON 46 49 43 59 / 50 40 40 10 NEWTON 51 55 45 59 / 60 40 40 10 ELDORADO 57 62 46 59 / 60 50 60 10 STROTHER FIELD 60 65 47 59 / 70 60 60 10 RUSSELL 42 46 40 58 / 30 30 20 5 GREAT BEND 43 47 41 59 / 40 30 30 10 SALINA 44 48 42 59 / 30 30 30 10 MCPHERSON 45 48 43 59 / 40 30 40 10 COFFEYVILLE 62 73 48 58 / 70 70 90 30 CHANUTE 61 69 48 58 / 60 60 90 20 IOLA 61 70 48 58 / 60 60 80 20 && .ICT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 18/COX ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 925 PM CDT THU APR 29 2004 .DISCUSSION... THE SURFACE COLD FRONT AT 02Z EXTENDED FROM HIAWATHA SOUTHWEST TO A HOLTON TO ALMA TO COUNCIL GROVE LINE. THE FRONT WILL PUSH SLOWLY SOUTHEAST ACROSS THE MOST OF THE FA BY SUNRISE AND BECOME STATIONARY TODAY ACROSS THE SOUTHEAST COUNTIES OF THE FA. SCATTERED SHOWERS WERE DEVELOPING ALONG AND BEHIND THE SURFACE COLD FRONT. AN UPPER 5H TROUGH OVER SOUTHERN UT WILL CONTINUE TO DIG SOUTHEAST INTO THE FOUR CORNERS REGION BY 12Z. THE 850 MB WINDS WILL CONTINUE TO ADVECT DEEPER MOISTURE NORTH OVER THE BOUNDARY TONIGHT. SYNOPTIC SCALE LIFT WILL INCREASE THROUGH THE NIGHT DUE TO UPPER LEVEL DIFFLUENCE AHEAD OF THE 5H TROUGH. I WILL PLACE SCATTERED RAIN SHOWERS WITH ISOLATED THUNDERSTORMS THROUGH THE REMAINDER OF THE EVENING THEN INCREASE POPS TO 50 PERCENT AFTER MIDNIGHT AS THE UPPER TROUGH APPROACHES NORTHWEST NM. ATTM THE BEST RAIN CHANCES FRIDAY WILL PROBABLY REMAIN ALONG AND SOUTH OF THE KS TURNPIKE. GENERALLY LOW TEMPS LOOK ON TRACK AND WILL BE DEPENDENT ON THE POSITION OF THE SURFACE FRONT THROUGH THE MORNING HOURS. I HAVE ADJUSTED THE SFC WIND GRIDS TO FIT THE POSITION OF THE SFC FRONT AND HAVE LEANED TOWARD THE RUC SOLUTION THROUGH THE NEXT 8 HOURS. PREVIOUS DISCUSSION MAIN FORECAST CONCERNS CENTER AROUND SURFACE FRONT POSITION...AND ASSOCIATED PRECIPITATION CHANCES THROUGH SATURDAY MORNING...THEN LOW TEMPERATURES SUNDAY AND MONDAY. WEAK WAVE IN H500 FLOW WAS ALL THAT WAS NEEDED TO TRIGGER EXPECTED SHOWERS THIS MORNING. SPEED OF THE WAVE WAS A LITTLE SLOWER THAN EXPECTED AS A SECONDARY FEATURE DEVELOPED FARTHER TO THE SOUTH. ALTHOUGH CLOUDS WERE WIDESPREAD ACROSS THE FORECAST AREA DURING THE MORNING...DRYING ASSOCIATED ALONG THE WEST AND NORTHWEST EDGE OF THE SHORTWAVE IN WATER VAPOR IMAGERY REDUCED MID-LEVEL MOISTURE DURING THE AFTERNOON. WITH SO MUCH CLOUDS DURING THE AFTERNOON...HEATING BASED CONVECTION HAS BEEN REDUCED AND EVENING POPS WILL BE REDUCED. HOWEVER...STILL BELIEVE ELEVATED CONVECTION IS STILL POSSIBLE OVERNIGHT AS ANOTHER SHORTWAVE TAPS THE MOISTURE AND LOW LEVEL JET OVER THE COLD FRONT. EXPECT THUNDERSTORMS TO ONGOING AT SUNRISE FRIDAY...ESPECIALLY ALONG AND SOUTH OF THE KANSAS TURNPIKE WITH A LESSER THREAT TOWARD THE NEBRASKA BORDER. PRECIP THREAT SHOULD LOWER FORECAST AREAWIDE DURING THE AFTERNOON WITH OUTFLOWS DISRUPTING THE AIR AND THE COLD FRONT PUSHING TO THE SOUTHEAST. FRIDAY NIGHT IS A CONCERN FOR HEAVY RAINS ALONG AND SOUTH OF I-35 DEPENDING ON THE FINAL LOCATION OF THE SURFACE FRONT. AT THIS TIME THE H850 FRONT WILL BE LAYING OVER THAT AREA WITH THE H700/500 WAVE CROSSING THE REGION. REMAINING SHOWERS SHOULD END EARLY SATURDAY OVER THE SOUTHEAST WITH CLOUDS DECREASING FROM THE NORTHWEST. SUNDAY THROUGH THURSDAY...MAIN UPPER TROF AXIS WILL BE JUST EAST OF THE FORECAST AREA SUNDAY MORNING...HOWEVER ECMWF AND RECENT VERSIONS OF GFS EMBEDS A TRAILING SHORTWAVE ON THE BACKSIDE OF THE UPPER TROF. THIS COULD CREATE SOME LIGHT RAIN ON SUNDAY...BUT AT THE CURRENT TIME WILL EXCLUDE SINCE THIS FEATURE IS MINIMAL AND WILL BE DEPENDENT ON THE ACTUAL LOCATION OF THE UPPER FEATURE. TEMPERATURES SUNDAY AND MONDAY MORNINGS WILL BE QUITE COOL WITH 35-40 BEING COMMON ACROSS THE FORECAST AREA. THIS WILL HAVE TO BE WATCHED WITH THE GROWING SEASON GETTING INTO FULL SWING FOR FROST POTENTIAL...ESPECIALLY MONDAY MORNING WITH CLEARING SKIES AND LIGHT WINDS. && .TOP...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ks AREA FORECAST DISCUSSION...ADDED CCF NUMBERS NATIONAL WEATHER SERVICE WICHITA KS 338 PM CDT THU APR 29 2004 .DISCUSSION... MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE THE POSITION OF THE FRONT AND HEAVY RAINFALL POTENTIAL DURING THE NEXT COUPLE OF DAYS. TONIGHT: LATEST VISIBLE IMAGERY SHOWING A WELL DEFINED COLD FRONT CONTINUING TO PLOW INTO CENTRAL KANSAS. THIS FRONT HAS ACTED TO PRODUCE LOTS OF LOW CLOUDS BEHIND IT. AHEAD OF THE FRONT, THINGS ARE TRYING TO SCOUR OUT ACROSS THE SOUTHWEST PART OF THE CWFA WHERE THE CAP APPEARS TO BE A LITTLE WEAKER. FURTHER EAST, THE CAP LOOKS TO BE RATHER STRONGER ACCORDING TO THE LATEST RUC SOUNDING. LATEST RUC ANALYSIS SHOW THIS FRONT PUSHING INTO SOUTH CENTRAL KANSAS THIS EVENING AND HANGING UP ALONG A LINE FROM NEAR ICT TO MARION. RIGHT NOW, I WOULD EXPECT SOME THUNDERSTORMS TO FIRE IN THE WEAK CAPPED AREAS OF NORTHWEST OK LATE THIS AFTERNOON WITH THE MEAN LEVEL FLOW SHIFTING THESE STORMS INTO SOUTH CENTRAL KANSAS AFTER 6 PM. SURFACE BASED CAPE VALUES COULD REACH 2000J/KG IF THINGS CLEAR OUT. HOWEVER, SHEAR VALUES ARE VERY MINIMAL WHICH MEANS THAT MOST OF THE STORMS WILL PROBABLY BE MULTICELLULAR WITH THE HAIL BEING THE MAIN THREAT. OVERNIGHT MORE THUNDERSTORMS WILL DEVELOP ACROSS SOUTH CENTRAL AND SOUTHEAST KANSAS WHERE DECENT ISENTROPIC LIFT WILL BE IN PLACE ESPECIALLY AROUND 305K. TOMORROW: THE MAIN QUESTION WILL BE THE POSITION OF THE FRONTAL BOUNDARY TOMORROW. THIS WILL BE PLAY A BIG ROLE IN THE TEMPERATURE DEPARTMENT. THE ETA APPEARS TO HAVE THIS FRONT TOO FAR NORTH, AFTER LOOKING AT THE LATEST RUC ANALYSIS. WE WILL KEEP THE FRONT SITUATED MAINLY ALONG AND NORTH OF A HUTCHINSON TO MARION LINE, BUT IT COULD DIVE SOUTH DURING THE COURSE OF THE DAY, DUE TO LOTS OF CONVECTION AROUND. HOWEVER, THIS COULD BE ALTERED IN LATER FORECASTS. NORTH OF THE FRONTAL BOUNDARY, TEMPERATURES WILL STRUGGLE TO GET OUT OF THE 40S DUE TO LOTS OF LOW CLOUDS IN PLACE. SOUTH OF THE BOUNDARY TEMPERATURES WILL REACH THE 60S AND 70S. MORE SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP DURING THE COURSE OF THE DAY, WITH MOST OF THE FOCUS EXPECTED ALONG AND SOUTH OF THE FRONTAL BOUNDARY. FRIDAY NIGHT-SATURDAY: WATER VAPOR LOOP CONTINUES TO SHOW MORE ENERGY DIVING BEHIND THE UPPER LEVEL WAVE IN THE ROCKIES. ONCE THIS WAVE, ROUNDS THE BASE OF THE TROF, IT WILL HELP SHIFT THE TROF EAST FRIDAY NIGHT AND SATURDAY. THE MODELS CONTINUE TO SLOW THINGS DOWN WITH THIS WAVE, WHICH HAS LED ME TO KEEP THE CHANCE OF RW- GOING INTO SATURDAY MORNING. THERE WILL BE SOME AID FROM THE RIGHT ENTRANCE REGION OF THE UPPER LEVEL JET ACROSS SOUTHEAST KANSAS WHICH RAISES A FLAG TO THE HEAVY RAIN POTENTIAL ACROSS SOUTHEAST KANSAS FRIDAY NIGHT. IT LOOKS LIKE THE MAIN SYNOPTIC SCALE LIFT WILL BE FRIDAY NIGHT. HOWEVER, THERE IS SOME QUESTION ON HOW FAST THE FRONT WILL MOVE THROUGH. IF THE FRONT HOLDS UP IT WE COULD END UP WITH SOME FLOODING POTENTIAL FOR SOUTHEAST KANSAS. RIGHT NOW, THE MODELS ARE FAIRLY PROGRESSIVE WITH THIS FRONT, AND SHIFT IT THROUGH SOUTHEAST KANSAS AFTER MIDNIGHT FRIDAY. WE WILL HOLD OFF ON A FLOOD WATCH FOR NOW, SINCE MOST OF THIS WILL BE DEPENDENT ON WHERE THE FRONT HANGS UP. SUNDAY-MONDAY: VERY UNSEASONABLE LIKE TEMPERATURES WILL BE IN STORE FOR THE AREA. IN FACT, MONDAY MORNING WE COULD BE FLIRTING WITH A FROST ADVISORY AS HIGH PRESSURE SETTLES IN PLACE. TUESDAY-THURSDAY: UPPER LEVEL RIDGE WILL BUILD OVER THE CWFA AND ALLOW FOR A NICE WARMUP FOR THE REST OF THE WEEK. TEMPERATURES SHOULD REBOUND TO THE 70S AND 80S WEDNESDAY AND THURSDAY AS THE LEE SIDE TROF SETS UP. && .PRELIMINARY POINT TEMPS/POPS... WICHITA 55 60 45 59 / 60 50 40 10 HUTCHINSON 46 49 43 59 / 50 40 40 10 NEWTON 51 55 45 59 / 60 40 40 10 ELDORADO 57 62 46 59 / 60 50 60 10 STROTHER FIELD 60 65 47 59 / 70 60 60 10 RUSSELL 42 46 40 58 / 30 30 20 5 GREAT BEND 43 47 41 59 / 40 30 30 10 SALINA 44 48 42 59 / 30 30 30 10 MCPHERSON 45 48 43 59 / 40 30 40 10 COFFEYVILLE 62 73 48 58 / 70 70 90 30 CHANUTE 61 69 48 58 / 60 60 90 20 IOLA 61 70 48 58 / 60 60 80 20 && .ICT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 18/COX ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 135 PM MDT THU APR 29 2004 .DISCUSSION...FORECAST CONCERNS ARE WHEN AND HOW MUCH PRECIP WILL FALL TONIGHT THROUGH FRIDAY NIGHT. GOODLAND NEEDS 0.33 INCHES TO REACH #10 FOR WETTEST APRILS. OTHER CONCERNS ARE THE IMPACT OF THE RAIN ON AFTERNOON HIGH TEMPERATURES. FINALLY...FORECAST FOCUS IS ON THE EXTENDED FORECAST AND HOW WARM IT WILL GET. TONIGHT-FRIDAY...UPPER LEVEL LOW PRESSURE AREA CURRENTLY OVER SOUTHWEST UTAH WILL MOVE TOWARD THE FOUR CORNERS AREA TONIGHT... CONTINUING EASTWARD THROUGH CENTRAL COLORADO FRIDAY. UPPER LEVEL VORTICITY CENTERS WILL BEGIN AN APPROACH TO THE SOUTHWESTERN/WESTERN COUNTIES AFTER MIDNIGHT...PUSHING ACROSS THE AREA DURING THE DAY THURSDAY. MOST OF THE FORECAST AREA WILL SUCCUMB TO THE LEFT FRONT QUAD OF THE UPPER JET WHICH COMBINED WITH INCREASING MOISTURE THROUGHOUT THE ATMOSPHERE PRODUCE WIDESPREAD LIGHT RAIN AFTER MIDNIGHT TONIGHT THROUGH THURSDAY. THIS IS AGREED UPON BY THE ETA/GFS/NGM/NCEP/MM5/LAMP QPF PROBABILITY FORECASTS (THROUGH 06Z) AND FSL RUC II. BOUNDARY LAYER/850 TEMPERATURES WOULD SUPPORT EITHER A MIX OR ALL SNOW FOR OUR FAR EASTERN COLORADO COUNTIES BOTH TONIGHT AND FRIDAY. ACCUMULATING SNOW...IF YOU BELIEVE THE MODELS (WHICH HAVE DONE VERY POORLY WITH SNOWFALL FORECASTS OF LATE) WOULD BE CONFINED TO FAR EASTERN COLORADO DURING THE DAY FRIDAY. WILL UNDERCUT GUIDANCE TEMPS JUST A BIT GIVEN THE NORTHEAST WINDS/PRECIP AND EXTENSIVE CLOUDINESS. FRIDAY NIGHT/SATURDAY...AS THE UPPER LEVEL TROUGH AND JET ENERGY MOVE AWAY FROM THE AREA HIGH PRESSURE PUSHES OUR MOISTURE SOURCE SOUTHWARD...BRINGING AN END TO THE PRECIPITATION FROM NORTH TO SOUTH FRIDAY NIGHT. AGAIN...THIS IS AGREED UPON BY THE GFS/NGM/ETA/MM5/FSL RUC II/NCEP. ON SATURDAY EXPECT A RETURN TO SOME SUNSHINE AS HIGH PRESSURE AND SOME DRIER AIR BECOME PREVALENT. SATURDAY NIGHT/SUNDAY...UPPER LEVEL RIDGING BEGINS TO TAKE HOLD AS A RATHER LARGE UPPER TROUGH TAKES OVER ACROSS THE CENTRAL PART OF THE COUNTRY. ONLY FORECAST CHALLENGE HERE WILL BE TEMPERATURES. 850 TEMPERATURES FROM THE ETA SUPPORT HIGHS NEAR 70 WHILE GFS IS COOLER WITH LOWER 60S. LOOKING AT ETA/ECMWF/GFS/GFS180 IT LOOKS LIKE A SPLIT WOULD BE REASONABLE SO WILL LEAVE CURRENT FORECAST OF MID 60S AS IS. MONDAY...UPPER LEVEL TROUGH MOVES EAST OF THE AREA THROUGH THE PERIOD WHILE UPPER RIDGING BUILDS OVER THE SOUTHWEST. TEMPERATURES SUNDAY WILL REBOUND TO NEAR NORMAL READINGS WHILE ON MONDAY WARM TOWARD 80 DEGREES. TUESDAY...UPPER RIDGE AXIS BUILDS ACROSS THE AREA...AHEAD OF ANOTHER UPPER LOW PRESSURE AREA PUSHING ITS WAY TOWARD THE PACIFIC NORTHWEST. 850 TEMPERATURES FROM CURRENT AND PREVIOUS MRF CONTINUE TO SUPPORT HIGHS IN THE MID TO UPPER 80S...ABOUT TEN DEGREES ABOVE MEX GUIDANCE. WEDNESDAY/THURSDAY...ABOVE MENTIONED UPPER LOW A BIT SLOWER THAN YESTERDAYS RUN AS ITS NOW FORECAST TO REACH THE PACIFIC NORTHWEST COAST WEDNESDAY AND REMAIN STATIONARY THURSDAY. DOWNSTREAM RIDGE STILL IN TACT AS IS THE WARMING TREND. 850 TEMPERATURES CONTINUE TO WARM AND WOULD SUPPORT HIGHS IN THE 90S BOTH DAYS. WILL WARM TEMPERATURES ABOUT 3 TO 5 DEGREES FROM PREVIOUS FORECAST WEDNESDAY AND THURSDAY TO HINT AT THE TREND AND MORE CONFIDENCE AS WELL AS STAY WITHIN GUIDELINES WITH SURROUNDING OFFICES. $$ .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ DDT ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 910 PM EDT THU APR 29 2004 .DISCUSSION... FCST CONCERNS OVERNIGHT ARE RAIN TRENDS AND POTENTIAL OF SNOW TO MIX WITH RAIN. RAIN HAS FILLED IN NICELY OVER UPPER MI THIS EVENING...EXCEPT FOR THE NW WHICH IS DEEPER INTO LOW-LEVEL DRY AIR. PCPN IS DEVELOPING AS A RESULT OF UPPER LEVEL DIVERGENCE IN RIGHT ENTRANCE REGION OF JET ACROSS ONTARIO. NICE AREA OF RESULTING 850-700MB FRONTOGENESIS IS ALSO DEPICTED BY RUC/ETA. 18Z ETA ACTUALLY HAS AN EXCELLENT HANDLE ON PCPN AREA THIS EVENING...AND AMOUNTS LOOK QUITE REASONABLE AS WELL. IT MIGHT BE A LITTLE QUICK MOVING PCPN AREA S AND E DURING THE EVENING/NIGHT THOUGH. TEMPS CONTINUE TO FALL ACROSS THE HIGHER TERRAIN OF NCNTRL FCST AREA...AND HERE AT THE OFFICE...TEMP IS HOVERING AT 33 WITH SOME SLOPPY SNOWFLAKES MIXING WITH THE RAIN AT TIMES WHEN HEAVIER PCPN OCCURS. SHARPLY INCREASED RADAR REFLECTIVITIES SHOWING UP ON THE 0.5 DEGREE SLICE FROM NRN IRON INTO WRN MARQUETTE COUNTY IS ALSO SUGGESTIVE OF INCREASING POTENTIAL OF WET SNOWFLAKES REACHING THE GROUND. WITH OVERALL WARM BNDRY LAYER AND WEAK CAA...SNOW WILL PROBABLY BE CONFINED TO TIMES OF HEAVIER PCPN...SO IT SEEMS UNLIKELY THAT A COMPLETE CHANGEOVER WILL OCCUR. IF A COMPLETE CHANGEOVER TO SNOW DOES OCCUR IN A FEW SPOTS... WOULDN'T BE SURPRISED TO SEE A SLUSHY INCH OF ACCUMULATION. HAVE ALREADY UPDATED FCST FOR TRENDS THIS EVENING. STILL EXPECT PCPN TO WIND DOWN FROM NW TO SE...BUT MAY DELAY TIMING A BIT AS 21Z RUC IS SLOWER TO MOVE FRONTOGENESIS OUT OVERNIGHT. WILL REEVALUATE TIMING AFTER A QUICK LOOK AT 00Z MODELS LATER THIS EVENING. && .PREV DISCUSSION... DISCUSSION FOR FRI THRU THU ISSUED AT 442 PM EDT. WILL KEEP SCT POPS GOING IN THE SE ZONES THROUGH FRI...CLOSEST TO THE SFC BOUNDARY WHICH WILL BE STRETCHED ACROSS THE CENTRAL GREAT LAKES...BUT DRY ELSEWHERE AS THE HIGH BUILDS. SAT THROUGH SUN...ETA/GFS/UKMET AGAIN SHOWING SUBSTANTIAL DIFFERENCES AS THEY ATTEMPT TO HANDLE THE APPROACHING NRN AND SRN BRANCH WAVES. H5 ANALYSIS SHOWS THE GFS INITIALIZED A BIT BETTER AT 12Z OVER THE HIGH PLAINS. DUE TO DIGGING NATURE OF CANADIAN WAVE... BUILDING RIDGE ALONG THE PAC COAST...AND FACT THAT HEIGHTS ARE NO LONGER FALLING OVER THE UPR GREAT LAKES...HAVE TO BELIEVE THE GFS/UKMET WHICH SHOWS MORE PHASING AND LOWER HEIGHTS IN THE CENTRAL PLAINS BY SAT MORNING. THE ETA APPEARS TO TAKE THE NRN WAVE TOO FAR EAST TOO SOON. SO...HAVE FOLLOWED THE GFS IN TERMS OF WINDS AND WX OVER THE NEXT FEW DAYS. FIRST WAVE RIDES UP ALONG SFC BOUNDARY LATE FRI...AND WILL KEEP WITH LIKELY POPS IN THE E AND S FOR FRI NIGHT. NEXT WAVE SAT NIGHT INTO SUN LOOKS TO OCCUR WHEN THE DEEPEST MOISTURE IS TO OUR E (PWATS DOWN TO AROUND 1/4 INCH OVER THE U P)...SO HAVE SCALED BACK POPS DURING THIS TIME TO ONLY CHANCE EVEN IN THE SE ZONES. DESPITE THE DRYING... WILL KEEP WITH MENTION OF RA OR SN OUT WEST BOTH SAT NIGHT AND SUN...AS A COUPLE OF PV MAXES SWING THROUGH AND TEMPS ALF COOL TO -30C BY SUN. PCPN BY SUN WILL PROBABLY BE MORE OF DIURNAL NATURE DUE TO THIS COLD POOL. H8 TEMPS DROP TO -8/-10C SAT NIGHT AND SUN...SO DOMINANT PCPN TYPE LOOKS TO CHANGE OVER TO SNOW...ESPECIALLY FOR THE WESTERN HIGHER TERRAIN. PRETTY IMPRESSIVE FOR EARLY MAY. BUILDING UPR RIDGE AND BACKING FLOW...AS WELL AS LOSS OF DAYTIME HEATING... WILL END PCPN SUN EVENING. IN THE EXTENDED...ALL MODELS SHOWING A PERIOD OF RETURN FLOW AND WARMER TEMPS ON MON (STILL A LITTLE BELOW NORMAL)...IN ADVANCE OF ANOTHER CLIPPER TO OUR NW. NEW GFS AND UKMET RUNS MUCH MORE AGGRESSIVE WITH THIS FEATURE THAN THE 00Z GFS/ECMWF/CANADIAN RUNS. WITH MUCH UNCERTAINTY AND LITTLE CONFIDENCE IN THE TIMING AND STRENGTH OF THIS WAVE AT THIS TIME...HAVE INTRODUCED SHRA TUE AFTN INTO EARLY WED AS A FRONT COMES THROUGH (AGAIN IT MAY BE FASTER THAN THIS). THEN A SFC RIDGE AND N TO E FLOW DEVELOPS WED. THE 00Z GFS SHOWED H8 TEMPS REMAINING ABOVE ZERO...BUT THE 006/12Z RUNS SHOW MUCH COLDER AIR COMING ACROSS LAKE SUPERIOR IN THE CLIPPER'S WAKE. WE'LL SEE. AFTER A DRY WED...NEXT CLIPPER COMES THROUGH THU. HAVE NEAR NORMAL TEMPS IN THE GRIDS FOR TUE-THU...BASED ON THE 00Z RUNS AND ENSEMBLE MEAN...BUT THIS MAY HAVE TO BE MODIFIED IF THESE WAVES TURN OUT TO BE STRONGER. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON (DISCUSSION) JKL (PREV DISCUSSION) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 330 PM EDT THU APR 29 2004 .SHORT TERM... LOOKS LIKE A WET PATTERN BEGINNING TONIGHT AND CONTINUING INTO SATURDAY. THE FRONT THAT IS TO CROSS THE AREA IS CURRENTLY LOCATED OVER NORTHERN LOWER MICHIGAN...STRETCHING SOUTHWEST INTO WISCONSIN. THIS FEATURE WILL DROP SLOWLY SOUTHEAST OVER THE NEXT COUPLE OF DAYS. MEANWHILE SOUTHWEST WINDS AHEAD OF IT WILL DRAW UP MOISTURE FROM THE GULF OF MEXICO...WHICH WILL INTERACT WITH THIS FRONT...PRODUCING RAIN. ONE 500 MB SHORTWAVE EMBEDDED WITHIN THIS GULF MOISTURE IS OVER THE MIDDLE MISSISSIPPI VALLEY AND LIFTING NORTHEAST. SHOWERS AND THUNDERSTORMS HAVE BEEN ON THE INCREASE ACROSS MISSOURI OVER THE PAST COUPLE OF HOURS. THIS AREA OF RAIN IS EXPECTED TO ARRIVE INTO SOUTHWEST LOWER MICHIGAN BY MIDNIGHT. I'LL KEEP THUNDER IN THE FORECAST DESPITE LIMITED INSTABILITY...AS THE LATEST RUC MODEL SUGGESTS KINDEX VALUES WILL BE CLIMBING INTO THE LOW 30S. WITH DEEP MOISTURE IN PLACE AND THE FRONTAL ZONE ACROSS THE AREA WILL KEEP HIGH PROBABILITIES GOING FOR SOME SHOWERS AND THUNDERSTORMS. THE MOST LIKELY PERIOD FOR RAIN LOOKS TO BE SATURDAY WHEN THE IMPRESSIVE LOOKING UPPER TROUGH OVER THE SOUTHWEST U.S. LIFTS OUT INTO THE PLAINS...CROSSING LOWER MICHIGAN. TOWARD THE TAIL END OF THIS SYSTEM...THE FREEZING LEVEL WILL BE LOWERING...LATER SATURDAY AFTERNOON INTO SATURDAY NIGHT. WILL NEED TO MONITOR THE POTENTIAL FOR SNOW. THE UPPER TROUGH DOES NOT ARRIVE UNTIL SUNDAY...SO WILL KEEP A LOW CHANCE FOR PRECIPITATION RUNNING. WILL KEEP THE MENTION OF A MIX ACROSS THE NORTH WHERE THE EARLY MAY AIR WILL BE COLDER. .LONG TERM... SOME RESIDUAL SHOWERS FROM THE UPPER TROUGH MOVING THROUGH LATER THIS WEEKEND WILL CONTINUE TO AFFECT THE AREA SUN NIGHT INTO MON MORNING. LOW LEVEL THICKNESSES AND FORECAST SOUNDINGS SUPPORT ANYTHING FROM RAIN TO SNOW DEPENDING ON THE MODEL. THE GFS SEEMS TO BE THE COLDEST AND PRODUCES MORE SNOW THAN RAIN. WILL GO WITH A RA/SN MIX SUN EVENING....THEN CHANGING OVER TO ALL SNOW UP NORTH OVERNIGHT SUN NIGHT. THE UPPER TROUGH WILL THEN PULL AWAY FROM THE AREA ON MON AND DIMINISH ANY PCPN THAT IS LEFT OVER. BEHIND THE TROUGH...NW UPPER FLOW WILL BUILD INTO THE AREA AS WILL A SFC RIDGE FOR LATER MON. THE LOW LEVEL THERMAL TROUGH WILL PASS EAST OF THE AREA ON MON...SO TEMPS WILL WARM A COUPLE OF DEGREES AS COMPARED TO SUN. THE SFC RIDGE WILL THEN PASS EAST OF THE AREA BY TUE...AND GOOD LOW LEVEL WARMING WILL TAKE PLACE DUE TO STRONG WAA FROM THE SW. A FLAT UPPER RIDGE WILL SET UP OVER THE MIDWEST FOR THE WED AND THU TIME FRAME. THE GFS TRIES TO BRING A COLD FRONT SOUTH THROUGH THE STATE DURING THE TUE NIGHT/WED MORNING TIME FRAME. THE 00Z/29 ECMWF AND THE 00Z/29 GEM ARE TENDING TO KEEP THIS FRONT FURTHER NORTH. WITH THE LACK OF UPPER SUPPORT EXPECTED AND THE FRONT BECOMING PARALLEL TO THE UPPER FLOW...I WOULD EXPECT THIS FRONT TO BECOME STATIONARY NORTH OF THE CWFA ATTM. GOING WITH THIS IDEA...WE SHOULD REMAIN DRY AND WARMER TUE THROUGH THU. && .GRR...WATCHES/WARNINGS/ADVISORIES...SMALL CRAFT ADVISORY IN EFFECT ENTIRE NEARSHORE TODAY. && MJS NJJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 930 PM EDT THU APR 29 2004 SURFACE RIDGE OFF THE MID-ATLANTIC COAST CURRENTLY EXTENDS WEST INTO NC...WITH SE WINDS NOTED OVER THE ILM CWA. PLENTY OF CONVECTION IN THE DEEP SOUTH...WORKING ACROSS ALABAMA AND INTO THE FLORIDA PANHANDLE. CURRENT ZFP IS WELL ON TRACK. WINDS HAVE YET TO DECOUPLE COMPLETELY BUT SHOULD LAY DOWN AROUND MIDNIGHT. EXPECT SOME OF THE MID AND HIGH DEBRIS CLOUDINESS FROM DEEP SOUTH CONVECTION TO REACH THE SC ZONES TOWARD MORNING. COULD TWEAK THE WORDING...HOWEVER THE CHANGES HAVE NOT TAKEN PLACE YET SO WILL LET THE ZFP RIDE AS IS. && .MARINE... RUC AND MESO-ETA ILLUSTRATE THE CENTER OF SURFACE HIGH OVER THE ATLANTIC WATERS WELL EAST OF NORTH CAROLINA...TO DRIFT A BIT FURTHER EAST OVERNIGHT. RIDGE AXIS FROM THIS HIGH TO MEANDER NORTH OF THE WATERS...RESULTING IN A CONTINUATION OF THE SOUTHEAST WIND DIRECTION OVERNIGHT. SURFACE PRESSURE GRADIENT TO SLIGHTLY INCREASE...ENUF TO GO 10 TO 15 KT. SEAS TO CONTINUE AT 2 TO 3 FT. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...NONE. SC...NONE. && PUBLIC: RAS MARINE: RALF && .PREVIOUS DISCUSSION (345 PM EDT)... CUMULUS FIELD HAS DEVELOPED ACROSS EASTERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON AHEAD OF THE SEA BREEZE. WITH THE LOSS OF DAYTIME HEATING...ONLY SOME CIRRUS IS EXPECTED TONIGHT. INCREASING MID-UPPER LEVEL MOISTURE WILL ALLOW THE CIRRUS TO INCREASE AND THICKEN LATER TONIGHT...AND BECOME BROKEN TO OVERCAST BY FRIDAY. THE ONSHORE WIND COMPONENT WILL ALLOW FOR CUMULUS TO DEVELOP ONCE AGAIN ON FRIDAY...AND WITH INCREASING LOW LEVEL MOISTURE... ESPECIALLY ACROSS SOUTHERN AREAS...WILL INTRODUCE A SLIGHT CHANCE OF PRECIPITATION. RAINFALL CHANCES INCREASE THROUGH THE WEEKEND AS THERE SHOULD BE PLENTY OF AVAILABLE MOISTURE ACCOMPANIED BY WEAK INSTABILITY. HOWEVER...DUE TO THE LACK OF ANY SIGNIFICANT LIFTING MECHANISMS WILL KEEP POPS IN THE CHANCE CATEGORY. THE MODELS CONTINUE TO SLOW THE EASTWARD PROGRESSION OF THE COLD FRONT...WHICH SEEMS REASONABLE GIVEN THE STRENGTH OF THE UPPER LEVEL RIDGE IN PLACE OVER THE WESTERN ATLANTIC. AT THIS TIME...IT APPEARS THAT THE COLD FRONT SHOULD MOVE ACROSS THE AREA AND OFFSHORE MONDAY. GOOD DYNAMICS AND INSTABILITY APPEAR TO BE PRESENT ALONG AND AHEAD OF THE FRONT...AND HAVE INCREASED TO LIKELY POPS SUNDAY NIGHT AND MONDAY. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT FOR THE MIDDLE OF NEXT WEEK WITH DRY CONDITIONS EXPECTED. AS FOR TEMPERATURES...WARM AIR ADVECTION WILL ALLOW HIGHS TO REACH OR SLIGHTLY EXCEED NORMAL VALUES THROUGH THE WEEKEND...ALTHOUGH THE ONSHORE FLOW WILL EASILY ALLOW FOR SEA BREEZE DEVELOPMENT AND THEREFORE COOLER BEACH TEMPERATURES. LOWS WILL ALSO CONTINUE TO MODERATE. ONCE THE COLD FRONT MOVES OFFSHORE...AN UPPER LEVEL TROUGH WILL BE IN PLACE OVER THE EASTERN U.S...RESULTING IN BELOW NORMAL TEMPERATURES TUESDAY AND WEDNESDAY. ONCE THE TROUGH SHIFTS OFFSHORE THURSDAY AND A RETURN SW FLOW DEVELOPS AT THE SURFACE...TEMPERATURES WILL QUICKLY MODERATE TO NORMAL VALUES. && .MARINE... FAIRLY STRAIGHTFORWARD IN THE SHORT TERM...QUITE A BIT MORE COMPLICATED TOWARDS THE END OF THE PERIOD. HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL BRING A GENERALLY SOUTHEAST TO SOUTHERLY FLOW TO THE COASTAL WATERS INTO SUNDAY. GRADIENTS WILL TIGHTEN THROUGH THAT PERIOD WITH THE APPROACH OF THE NEXT FRONTAL SYSTEM...CURRENTLY FORECAST TO MOVE OFFSHORE MONDAY. TIMING AT THIS POINT IS VERY UNCERTAIN AND FOR NOW WILL OPT TOWARDS A LESS PROGRESSIVE SOLUTION. GFS LINGERS THE FRONT OFFSHORE MONDAY AND TUESDAY WHILE SPINNING UP A FRONTAL LOW OVER THE EASTERN GULF OF MEXICO AND MOVING IT NORTHEAST ALONG THE FRONT. IF THIS HAPPENS...WILL DEFINITELY SEE FLAGS UP ON TUESDAY FOR AT LEAST SCA CONDITIONS. HOWEVER...NOT CONFIDENT THIS SCENARIO WILL PAN OUT AS TIMED BY THE GFS DUE TO RECENT MODEL PERFORMANCE. && .PRELIMINARY POINT TEMPS/POPS... WILMINGTON 55 77 63 77 / 0 10 10 30 FLORENCE 56 80 62 78 / 0 20 20 40 LUMBERTON 54 79 62 78 / 0 10 10 30 MYRTLE BEACH 57 75 64 74 / 0 20 20 30 && .ILM WATCHES/WARNINGS/ADVISORIES... NC...NONE. SC...NONE. && $$ PUBLIC: JAQ MARINE: REK nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OH 852 PM EDT THU APR 29 2004 .DISCUSSION... LATEST RUC AND MESO ETA KP PRECIP NR SRN LMIC NW OF CWA THRUT NITE. QUESTION IS WHETHER S/W LIFTING NNE FM LW MS VLY WL BE ABLE TO PUSH PRECIP AS FAR N AS OUR CWA BY DAYBREAK. BLV DRY AIR IN PLACE WL BE ENUF TO INHIBIT MOST OF THE MEASURABLE PRECIP FM MAKING IT INTO CWA TIL RIGHT AT DAYBREAK AT THE EARLIEST. HV BACKED UP ARRIVAL OF PSBL PRECIP BY PUSHING CHC TIL THE LAST HOUR OR TWO OF THE NIGHT. WL ADJUST TEMPS SLIGHTLY TO GO 55 TO 60 FOR AREAS WHERE PREV FCST WAS MID 50S AS CLDS AND SLY FLOW SHUD BE ENUF TO KEEP LOWS A BIT ABV GUIDANCE AND CERTAINTLY WRMR THAN LAST NITE. EXCEPTION WL BE FOR INLAND NW PA WHERE BEST CHC FOR MID 50S WL EXIST. BREEZY AND WINDY CONDS HV DIMINISHED SO WL REMOVE EVE WND WORDING. && .PREV DISCUSSION... HI PRES OFF E CST PROVIDED WRM SWLY FLOW ACRS CWA TDA THAT WILL CONT INTO SAT. THAT SWLY FLOW WL BGN TO BRING AN INCRS CHC OF SHWRS AND OR TSTMS BGNG LATE TNGT AND CONTG INTO SAT NITE. TNGT INCRS S-SWLY MOIST 8H FLOW AND WK SW AND MID AND UPR LVLS MAY BRING SOME SHWRS INTO W AND SWRN PTN CWA LATE TNGT. GFS OVER DONE WITH THE DYNAMICS OF THIS S/W AND POPS THEN TOO HIGH FOR MUCH CWA LATE TNGT AND ERY TMRW. CHC/SCT POPS FRI AND FRI NGT WITH HIGHEST POPS WRN PTN CWA. STILL SOME TIMING DIFFERENCE OF FNT BTW GFS AND ETS. ETS BRINGS FNT TO NW OH SAT MRNG WITH GFS LTL FURTHER W. PREFER THE WORDING OF SCT SHWRS AND TSTMS ATTM FOR SAT THOUGH POPS PBLY SHUD BE HIGHER. ETS APPEARS TO TRY MOV THE FNT OUT LTL TOO QUICLY THEN SAT NITE AND ERY SUN BUT DONT HAVE THE CONFIDENCE OF GFS DEVELOPING SUCH STG LOW/WAVES ALG FNT SAT NITE. STILL HIGH POPS SAT NITE DROPPING BACK TO CHC ON SUN. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. && $$ oh AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE NORMAN OK 735 PM CDT THU APR 29 2004 THUNDERSTORM COMPLEX THAT INITIATED EARLIER JUST EAST OF SURFACE LOW OVER LUBBOCK...HAS MOVED INTO SOUTHWEST OKLAHOMA AND WESTERN NORTH TEXAS. 00Z OUN SOUNDING SUPPORTS VISIBLE SATELLITE TRENDS OF WIDESPREAD STRATOCUMULUS CLOUDS OVER THE AREA...AT THE INVERSION HEIGHT OF 5000 FT. PROPAGATION IS EXPECTED TO BE A GREATER INFLUENCE ON THE CONVECTIVE EVOLUTION ONCE THE LOW LEVEL JET DEVELOPS...WITH THE COMPLEX ENCOUNTERING GREATER CONVECTIVE INHIBITION FARTHER EAST. THIS SHOULD RESULT IN THUNDERSTORMS TURNING MORE SOUTHWARD WITH TIME...REACHING NORTH CENTRAL AND CENTRAL TEXAS LATER IN THE NIGHT. THIS SCENARIO HAS LARGE IMPLICATIONS FOR THE FORECAST FARTHER NORTH ALONG THE COLD FRONT...WHICH WERE INITIALLY EXPECTING THE HIGHEST CHANCES OF RAIN OVERNIGHT. HOWEVER...THE LATEST ANALYSES AND RADAR/SATELLITE TRENDS SUGGEST OTHERWISE. EXPECT THE THUNDERSTORM COMPLEX TO INTERRUPT THE FLOW OF MOISTURE AND INSTABILITY FARTHER NORTH NECESSARY TO SUPPORT HIGH POPS...BUT DO EXPECT A FEW SHRA OR ISOLATED -TS FROM TIME TO TIME...AS IS BEGINNING TO OCCUR OVER NORTHWEST OKLAHOMA. HAVE MADE INITIAL UPDATES TO REFLECT THIS THINKING. ------------------------- 345 PM CDT THU APR 29 2004 .DISCUSSION... STRONG MID-SPRING COLD FRONT MAKING PROGRESS ACROSS HIGH PLAINS OF TEXAS PANHANDLE THIS AFTERNOON AND IS BEGINNING TO ENTER FAR NORTHWEST PART OF FA. APPEARS RUC HAS FAIRLY DECENT HANDLE ON FRONTAL POSITION AND PLACES IT FROM NEAR FAIRVIEW TO SOUTH OF ELK CITY TO AROUND HOLLIS BY 10 PM. STORMS DEVELOPING AHEAD OF FRONT IN TX PANHANDLE SO APPEARS MOST LIKELY AREA FOR INITIAL SEVERE DEVELOPMENT WILL BE ACROSS SOUTHWEST PARTS OF FA. FORECAST SHEAR PROFILES A LITTLE MORE FAVORABLE ACROSS THIS AREA ALSO. EXACT EVOLUTION OF STORMS THIS EVENING UNCLEAR BUT AS LLJ INTENSIFIES OVERNIGHT BEST CHANCE FOR CONVECTION SHOULD BE ACROSS NORTH CENTRAL/ CENTRAL PARTS IN VICINITY OF JET AXIS. OVERALL SETUP FOR ADDITIONAL STORMS ON FRIDAY WILL BE DEPENDENT UPON AMOUNT OF CONVECTIVE DEVELOPMENT THIS EVENING BUT WOULD IMAGINE THAT COLD FRONT WILL BE FARTHER SOUTH THAN ETA/GFS SUGGEST GIVEN CURRENT TRENDS. HAVE THEREFORE LOWERED TEMPS ACROSS NORTHERN SECTIONS FOR HIGHS TOMORROW AND LOWS FOR TONIGHT. EXPECT SIMILAR WEATHER ON FRIDAY WITH CENTRAL AND SOUTHERN PARTS OF THE FA HAVING THE BEST CHANCE FOR SEVERE THUNDERSTORMS. WILL GRADUALLY DRY THINGS OUT GOING INTO SATURDAY MORNING AS FRONT PUSHES INTO NORTHEAST PARTS OF TEXAS. REST OF EXTENDED FORECAST WILL BE DRY WITH BELOW NORMAL TEMPS TO START THE WORK WEEK. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 64 77 48 65 / 50 50 60 10 HOBART OK 57 73 44 67 / 60 20 30 10 WICHITA FALLS TX 64 85 52 67 / 30 30 60 10 GAGE OK 47 61 40 65 / 40 20 20 10 PONCA CITY OK 62 69 46 62 / 60 50 60 10 DURANT OK 67 82 57 67 / 0 50 60 30 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 6 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 345 PM CDT THU APR 29 2004 .DISCUSSION... STRONG MID-SPRING COLD FRONT MAKING PROGRESS ACROSS HIGH PLAINS OF TEXAS PANHANDLE THIS AFTERNOON AND IS BEGINNING TO ENTER FAR NORTHWEST PART OF FA. APPEARS RUC HAS FAIRLY DECENT HANDLE ON FRONTAL POSITION AND PLACES IT FROM NEAR FAIRVIEW TO SOUTH OF ELK CITY TO AROUND HOLLIS BY 10 PM. STORMS DEVELOPING AHEAD OF FRONT IN TX PANHANDLE SO APPEARS MOST LIKELY AREA FOR INITIAL SEVERE DEVELOPMENT WILL BE ACROSS SOUTHWEST PARTS OF FA. FORECAST SHEAR PROFILES A LITTLE MORE FAVORABLE ACROSS THIS AREA ALSO. EXACT EVOLUTION OF STORMS THIS EVENING UNCLEAR BUT AS LLJ INTENSIFIES OVERNIGHT BEST CHANCE FOR CONVECTION SHOULD BE ACROSS NORTH CENTRAL/ CENTRAL PARTS IN VICINITY OF JET AXIS. OVERALL SETUP FOR ADDITIONAL STORMS ON FRIDAY WILL BE DEPENDENT UPON AMOUNT OF CONVECTIVE DEVELOPMENT THIS EVENING BUT WOULD IMAGINE THAT COLD FRONT WILL BE FARTHER SOUTH THAN ETA/GFS SUGGEST GIVEN CURRENT TRENDS. HAVE THEREFORE LOWERED TEMPS ACROSS NORTHERN SECTIONS FOR HIGHS TOMORROW AND LOWS FOR TONIGHT. EXPECT SIMILAR WEATHER ON FRIDAY WITH CENTRAL AND SOUTHERN PARTS OF THE FA HAVING THE BEST CHANCE FOR SEVERE THUNDERSTORMS. WILL GRADUALLY DRY THINGS OUT GOING INTO SATURDAY MORNING AS FRONT PUSHES INTO NORTHEAST PARTS OF TEXAS. REST OF EXTENDED FORECAST WILL BE DRY WITH BELOW NORMAL TEMPS TO START THE WORK WEEK. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 64 77 48 65 / 50 50 60 10 HOBART OK 57 73 44 67 / 60 20 30 10 WICHITA FALLS TX 64 85 52 67 / 30 30 60 10 GAGE OK 47 61 40 65 / 40 20 20 10 PONCA CITY OK 62 69 46 62 / 60 50 60 10 DURANT OK 67 82 57 67 / 0 50 60 30 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 6 ok AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1056 AM EDT THU APR 29 2004 .UPDATE... LOOKS LIKE A MODIFIED PERSISTENCE SCENARIO WILL WORK WELL FOR THIS AFTERNOON. UPPER LEVEL RIDING STILL IN CONTROL...WHILE LOW LEVEL RIDGE HAS SHIFTED NORTHEAST A TAD SINCE YESTERDAY. THIS WILL ALLOW A LITTLE MORE MOISTURE INTO THE CAROLINAS AS IS EVIDENT ON LATEST VIS AND INCREASING SFC DEWPOINTS. RUC/META MODEL SOUNDINGS SUGGEST WARMER MAX TEMPS AND PREVAILING FORECAST GRIDS HANDLE THIS NICELY ACROSS THE CWFA. && .PREV DISCUSSION... A PROGRESSIVE...LOW AMPLITUDE RIDGE WILL MOVE ACROSS THE REGION TODAY...SETTING UP A DEEP SOUTHWEST FLOW ACROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA BY LATE IN THE DAY. EXPECT THIN CIRRUS TO CONTINUE PASSING OVER THE AREA...WHILE THE MODELS DEPICT LOW LEVEL ATLANTIC MOISTURE ADVECTING INTO THE REGION AROUND THE WESTERN PERIPHERY OF THE SURFACE HIGH. THE ETA...AS USUAL...IS MUCH MORE AGRRESIVE (AND PROBABLY OVERDONE) WITH THIS MOISTURE RETURN... BUT THE EVEN THE GFS DEPICTS SOME MOISTURE INCREASE BELOW H8 THIS AFTERNOON...SO WE SHOULD SEE SOME CU OVER THE SOUTHWEST HALF OF THE CWA...AND SKY COVER WILL RANGE FROM PARTLY CLOUDY SOUTHWEST TO MOSTLY SUNNY NORTHEAST. SW TROUGH CURRENTLY OVER THE SOUTHERN PLAINS WILL BE KICKED INTO THE EASTERN STATES TODAY BY STRONG TROUGH DIGGING INTO THE DESERT SOUTHWEST. THE PLAINS WAVE WILL SHEAR OUT AS IT ENCOUNTERS THE STRONGLY CONFLUENT FLOW TO ITS EAST. HOWEVER...THE VORT IS STRONG ENOUGH TO INVOKE A LOW LEVEL RESPONSE ACROSS OUR AREA IN TERMS OF BACKING AND STRENGTHENING THE LOW LEVEL FLOW. THE RESULTING ENHANCED UPSLOPE FLOW INTO THE SOUTHERN ESCARPMENT COULD SPAWN A FEW SHOWERS TONIGHT. MEANWHILE...THE ETA AND THE GFS SET UP A NICE LOW LEVEL CONFLUENT/CONVERGENT AXIS JUST WEST OF OUR AREA...AND BOTH MODELS BREAK OUT PRECIP ACROSS ROUGHLY THE WESTERN 1/3 OF THE CWFA AFTER MIDNIGHT. WE WILL RESPOND BY INCREASING POPS INTO THE CHANCE CATEGORY OVERNIGHT...GENERALLY WEST OF I-26. FRIDAY...FOR THE SAME REASONS AS MENTIONED ABOVE...THE BEST CHANCES FOR PRECIP SHOULD REMAIN ACROSS THE WEST...AND WILL WITHHOLD MENTIONABLE POPS FROM THE EASTERN 1/3 OF THE CWA. THE CONVERGENT/ CONFLUENT ZONE WEST OF THE AREA WILL WEAKEN DURING THE DAY...AS THE MID LEVEL WAVE...OR WHAT'S LEFT OF IT...LIFTS NORTHEAST OF THE REGION. THIS WILL LEAVE A SOUTHERLY UPSLOPE FLOW AS THE ONLY SOURCE OF LIFT FOR THE FRIDAY NIGHT PERIOD...BUT WE WILL MAINTAIN A LOW CHANCE POP FOR ALL AREAS WEST OF I-77. THE ATMOSPHERE WILL REMAIN MOIST...BUT WEAKLY FORCED ON SATURDAY... AND WON'T ARGUE WITH CURRENTLY ADVERTISED LOW CHANCE POPS. POPS WILL BEGIN TO INCREASE SATURDAY NIGHT AND SUNDAY...AS VIGOROUS FRONTAL SYSTEM APPROACHES THE REGION FROM THE TENNESSEE VALLEY. DEPENDING ON TIMING OF FROPA...SEVERE WEATHER AND/OR HEAVY RAINFALL COULD BE A CONCERN WITH THIS SYSTEM. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ NONE sc AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 1040 AM CDT THU APR 29 2004 .DISCUSSION... WHAT A DIFFERENCE A DAY MAKES...WITH MANY LOCATIONS 25-30F COOLER THAN THIS TIME YESTERDAY. RAOBS THIS MORNING INDICATE SIGNIFICANT SHALLOW COLD AIR PUSH INTO CWA...WITH MID LVL FRONT LINGERING OVR NRN CWA. UPR CONFLUENCE PATTERN NOT FORECAST TO ALTER MUCH THRU DAY...SO DO NOT EXPECT THINGS TO CHANGE TOO MUCH IN MID LVL MSTR FIELDS THRU DAY. MAIN ISSUE TODAY IS TEMPERATURES...WITH SECONDARY ATTENTION TO LOW PCPN THREAT. INITIAL ANLYS THIS MORNING OFF 06Z/12Z RELATIVE RUNS OF ETA/RUC SHOWING QUITE POOR HANDLING OF LOW LVL AIR COMPARING 12Z RAOB AT ABR WITH THERMAL PROFILES IN MDLS. REALITY IS MUCH STRONGER WITH SHALLOW CD PUSH WITH UP TO 4C DIFF BLO 925 HPA...SIDING TO COLDER THAN MDLS. HOPING THAT 12Z ETA COULD RECOGNIZE...BUT ACTUALLY CAME IN WITH WARMER 925 HPA FCST TMPS FOR AFTN THAN 06Z RUN. RUC ALSO PRODUCING A COPIOUS RAIN COOLED AIR POOL OVR HEART OF FSD CWA...WHICH OBVIOUSLY IS NOT HAPPENING. NEVERTHELESS... POOR INITIALIZATION IS STRONG SUPPORT TO LOWERING HIGHS TDA...BUT WL HAVE TO WATCH AREA OF MORNING SUNSHINE ACRS NW IA AND ADJACENT SW MN FOR TMPS RECOVERING QUICKLY. GENERALLY...CUT BACK HIGHS QUITE DRASTICALLY WITH EXPECTATION OF CLDS TO LINGER BENEATH UNDERFORECAST LOW LVL INVERSION. ONE AREA OF FRONTOGENESIS LINGER ACRS NRN CWA INTO NERN SD DURG AFTN...WHILE REFOCUS TO AREA ACRS SERN CWA DURG AFTN. VISIBLE SAT IMAGERY INDICATES SOME MID LVL ENHANCEMENT TO CLDS ABV MORE WIDESPREAD LOWER CLOUD DECK...MAINLY IN TWO AREAS CONICIDENT WITH FRONTOGENETIC FORCING. DRIER AIR CONTINUING TO ADVECT IN AT LOW LVLS...AND HAVE BEEN WAFFLING BACK AND FORTH BETWEEN MENTIONING LIGHT SHOWERS AND SPRINKLES. DECIDED TO GO WITH SCT SPRINKLES WITH PRECIP DEVELOPING TMPS NOT THAT FAVORABLE FOR EFFICIENT GROWTH. && .FSD...WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ CHAPMAN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 345 AM MDT FRI APR 30 2004 .SHORT TERM... (TODAY AND TONIGHT) ...POTENTIAL FOR SOME WELL NEEDED PRECIPITATION TONIGHT AND FRIDAY... CURRENTLY: IR/WV SATELLITE IMAGERY AND H5 RUC ANALYSIS INDICATED THAT THE UPPER LOW PRES SYSTEM WAS OVER THE FOUR CORNERS EARLY FRI MORNING...WITH WIDESPREAD RAIN AND SNOW RACING NORTH ACROSS THE CWA. LTG PLOTS ALSO INDICATED SOME ISOLATED LTG STRIKES ACROSS THE FAR SE CORNER OF THE STATE. THERE WAS A LARGE AREA OF DRIER AIR MOVING UP ACROSS NORTHERN NM AND INTO CO...BUT MOISTURE WAS WRAPPING AROUND THE LOW AND THERE WAS ACTUALLY SOME ENHANCEMENT DEVELOPING JUST SOUTH OF THE SANGRES...SO PRECIP SHOULD CONTINUE AFTER A POSSIBLE BRIEF LULL EARLY. TODAY: TOUGH FORECAST TODAY AS SLIGHT VARIATIONS IN THE TRACK OF THE UPPER LOW WILL EQUATE TO BIG DIFFERENCES IN PRECIP AMOUNT AND TYPE OUTCOME. BOTH ETA AND GFS MOVE THE UPPER LOW EAST ACROSS THE CO/NM BORDER EARLY THIS MORNING...THEN BY THE AFTN DROPS IT TO THE SE AS THE LOW OPENS UP. AS MENTIONED...AN AREA OF DRIER AIR WAS TRYING TO EDGE UP INTO THE REGION...PUSHING THE ONGOING PRECIP NORTH UP AGAINST THE PALMER DIVIDE. THIS IS DEPICTED BY MODEL PRECIP CHARTS...WITH FOCUS AREA RESTING ON THE PIKES PEAK AND N EL PASO COUNTY AREA...THEN SHIFTING OVER TO THE CENT MTS. AS THE LOW MOVES EAST THIS AM...HEALTHY UPSLOPE FLOW AND 300K ISENTROPIC UPGLIDE BECOMES MORE SOUTHERLY/PARALLEL...WHICH REINFORCES PUSHING THE PRECIP NORTH. BUT...PRECIP CHARTS DIFFER ON EXTENT OF COVERAGE TODAY...AND DO NOT THINK CHANGING MUCH FOR THE FIRST PERIOD WOULD BE PRUDENT. DECIDED TO CONTINUE THE VARIOUS ONGOING ADVISORIES AND WARNINGS...BUT IF THE EXPECTED REDEVELOPMENT OF PRECIP DOES NOT TAKE PLACE BY LATE MORNING THEN THE HIGHLIGHTS MIGHT BE TAKEN DOWN. WITH A BRIEF LULL IN THE PRECIP EXPECTED...MAX TEMPS SHOULD CREEP UP INTO THE LOWER 40S...BUT STILL NOT MUCH OF A DIURNAL SWING TODAY. ALSO ADDED ISOLATED THUNDER FOR BACA AND PROWERS COUNTIES TODAY DUE TO ONGOING CONVECTION IN THE VICINITY THIS MORNING...AND BETTER LAPSE RATES FOR THE SE CORNER. TONIGHT: THE UPPER TROUGH MOVES ACROSS SE CO INTO THE OK AND TX PANHANDLES...WITH A VORT BAND HANGING BACK ACROSS S CENT NM. THE FLOW BECOMES MORE NW WHICH SHOULD EFFECTIVELY SHUT OFF MOST OF THE PRECIP. PAINTED MOST OF THE AREA WITH ISOLATED POPS AROUND THE MIDNIGHT TIME FRAME...THEN DRY PRIOR TO SUNRISE. JUST SOME SLIGHT ADJUSTMENTS TO MIN T GRIDS WITH LATEST NUMERICAL GUIDANCE...AND LITTLE CHANGE NEEDED TO ONGOING WINDS/SKY COVER. \\MOORE// .LONG TERM... (SATURDAY THROUGH SUNDAY) ...QUIET WEATHER... NOT MUCH TO WRITE ABOUT THIS MORNING AS GUIDANCE CONTINUES TO INDICATE WX DURING THIS PERIOD WILL REMAIN DRY. PRECIP ASSOCIATED WITH ONGOING EVENT SHOULD COMPLETELY MOVE OUT BY 12Z SAT. TEMPS WILL REBOUND SAT INTO THE 50S AND 60S PLAINS...WITH 60S AND 70S BY SUNDAY. AREAS OF HVYR SNOW WHICH WE ARE GETTING MAY PLAY INTO HIGHS SAT BUT WILL HAVE TO WAIT FOR REPORTS/VIS SAT PIX TO GET FEEL FOR WHERE MOST OF IT FELL. FOR THE REST OF THE WEEK...RIDGE ALOFT OVER AREA. RIDGE NOT AS HIGH IN AMPLITUDE AS PREVIOUS RUNS...BUT STILL WE SEE TEMPS WARM INTO THE 80S MOST PLAINS FOR THE WEEK. NO SIGNIF WX SEEN ON THE HORIZON. \/HODANISH && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING...COLLEGIATE/MOSQUITO MT RANGES (058/060/061/ 063)...TELLER COUNTY (081/082)...WET MTS (079/080)...AND SANGRE DE CRISTO MTS (072>075) UNTIL 5PM THIS AFTERNOON. WINTER WEATHER ADVISORY...MID AND UPPER AR RIVER VALLEYS (059/062/077/078)...ERN SAN JUAN/LA GARITA MTS (068/066)...SOUTHERN FOOTHILLS (087/088)...AND NRN EL PASO COUNTY (084) UNTIL 5PM THIS AFTERNOON. && $$ co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 331 AM CDT FRI APR 30 2004 .SHORT TERM...TDA THRU SUN NGT PRIMARY FCST CONCERNS WL BE PCPN TRENDS INTO TNGT...AND AGN LATE SAT INTO EARLY SUN. NOT MUCH HAPPENING HERE OUTSIDE OF ISOLD SHWRS WITH UPR LOW OVR RCKYS...SRN CANADIAN TROF JUST APCHG BORDER...AND ASSOCD UPR LVL JET STILL N OF GRTLKS. 07Z SFC ANLYS PLACES FNTL BNDRY ALG KMCI-KCNC-KCID LN WITH VERY GRDL SLY MOVMT. LTL ISENT LIFT OVR THIS BNDRY IN IA ATTM WITH MOST H85/H7 THETA-E ADVCTN STILL OFF TO OUR S AND W. QUESTION BCMS PCPN DVLPG UPSTREAM OVR KS. THIS APPRS TO BE DRIVEN BY VORT LOBE AND DPVA PEELING OUT FM RCKYS LOW INTO SRN PLAINS AND AFOREMENTIONED THETA-E ADVCTN. ETA/GFS SIMILAR WITH LG WV FEATURES THRU WEEKEND BUT THERE ARE ENOUGH TIMING AND QPF DIFFERENCES TO IMPACT FCST. ETA SEEMS TO BE DOING BETTER WITH SLOWER FNTL PROGRESSION AND QPF ATTM. HWVR GFS STGR AND FARTHER NW WITH QPF INTO SERN IA LATER TDA. THIS MAY BE A RESULT OF SOME SORT OF CONVECTIVE FEEDBACK THIS MRNG WHICH OVER-INTENSIFIES A SHRT WV MOVG INTO MID MS VLY...AS WELL AS ENTRANCE RGN OF JET SEGMENT FM KMSP NEWD AND ASSOCD RIGHT REAR UPR LVL DVRGNC. HWVR 03Z RUC HAS SIMILAR TRENDS...MAYBE EVEN A BIT FARTHER NW...AND LATEST RUC ALSO DEPICTS H85/H7 FRONTOGENETICAL FORCING LINGERING SW-NE ACRS IA ATTM. TAKING THIS IN MIND AND EXTRAPOLATION OF CURRENT UPSTREAM PCPN...HAVE LEANED CLOSER TO GFS PCPN SOLUTION. GFS INCRS KINEMATIC FORCING TDA REFLECTED IN WEAK-MOD QG FORCING INFLUENCED BY BOTH NRN AND SRN STREAMS BEFORE PUSHING OFF JUST TO THE SE OVNGT. WEAK-MOD THETA-E ADVCTN ALSO SPREADS INTO SERN IA BY AFTN IN FRONTOGENETICAL FORCING ZN SO HAVE GONE WITH LIKELY POPS SERN SXNS...AND A TIER OF CHC WORDING TO THE N. HAVE GONE WITH THUNDER WORDING PREDOMINATELY SE AS GFS ELEVATED INSTABILITY APPRS TO DCR JUST ENOUGH. HAVE BACKED OFF SOMEWHAT ON GFS QPF HWVR WHICH SEEMS OVERDONE...POSSIBLY DUE TO FEEDBACK. SHOULD THEN SEE A BREAK IN PCPN TIL MINOR SHRT WVS DROP INTO BACK SIDE OF DEPARTING TROF. DO NOT HAVE GOOD FEELING ABT THIS PD AT ALL...BUT STILL LEANED TWRD GFS GOING WITH SLGT CHC/CHC CATEGORY POPS...MAINLY NRN AND ERN PTNS. THOUGHT I WAS DONE WITH PCPN TYPE...BUT HAVE GONE WITH LGT RAIN/SNW MIX WORDING FOR SAT NGT/EARLY SUN FAR NRN PTNS BASED ON GFS SOUNDINGS. DID NOT CHG GOING LOWS TNGT TOO MUCH WITH READINGS APCHG FRZG FAR NW. COULD SEE SOME PATCHY FROST IN NRN PTNS DEPENDING ON STRENGTH OF WND AND AMT OF CLDS BUT CONFIDENCE NOT HIGH ENOUGH TO MENTION ATTM. WRMD TEMPS UP A FEW DEGS SAT PER GUIDANCE AND MIXING POTENTIAL OF FCST SOUNDINGS. SAT NGT WL BE INTERESTING FOR FROST TOO. CLDS AND PCPN POTENTIAL WITH NWLY FLOW SHRT WV MAY KEEP US FREE HWVR. DATA FROM IOWA ENVIRONMENTAL MESONET CLIMODAT APPLICATION SUGGESTS THAT MEAN DATE OF LAST 32 DEGREE OCCURRANCE FOR NWRN/N CNTRL IA IS ARND MAY 1 ANYWAY SO THESE CONDS ARE NOT ATYPICAL. ETA MORE AGGRESSIVE WITH COLD AIR SURGE INTO NERN IA LATE SUN...AND WITH WRM UP EARLY MON. WRMD WRN PTNS TIGHTENING GRADIENT KEEPING NERN PTNS AS FCST. .LONG TERM...MON THRU THU LTL CHG HERE BUT DID MAKE A FEW ADJUSTMENTS TO BLEND INTO SURROUNDING WFOS BETTER...LOWERING NRN AND ERN HIGHS THU IN PARTICULAR. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE && $$ SMALL ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 355 AM MDT FRI APR 30 2004 .DISCUSSION...FORECAST CONCERNS WILL BE EASTWARD EXTENT OF RAIN/SNOW/SLEET MIX...FOR TODAY ALONG WITH TEMPERATURES AND TIMING THE END OF THE PRECIPITATION EARLY IN THE SECOND PERIOD. HIGH AMPLITUDE RIDGE ACROSS THE WEST COAST WITH A CLOSED LOW MOVING SLOWLY EAST/SOUTHEAST INTO NORTHERN ARIZONA. THE LATEST RUC APPEARS TO CAPTURE EXPANDING AREA OF PRECIPITATION ACROSS THE SOUTHWEST ZONES WITH ISENTROPIC LIFT ON THE 295K SURFACE...AND SHIFTS THIS AREA NORTH AND EAST ACROSS THE FORECAST AREA THROUGH 15Z. THE ETA/GFS ARE SOMEWHAT SIMILAR BUT FURTHER SOUTH/SOUTHEAST WITH THE BEST LIFT THROUGH AROUND 18Z. TIME/HEIGHT CROSS SECTIONS FROM ETA/GFS WOULD SUPPORT KEEPING HIGH POPS THROUGH AT LEAST 18Z WITH CONSIDERABLE DRYING IN THE COLUMN AFTER 00Z. WILL KEEP A CHANCE MENTION THROUGH 03Z AND REMOVE WEATHER/POPS AS HIGH PRESSURE PUSHES MOISTURE SOUTH OF THE AREA AS UPPER SYSTEM MOVES INTO THE SOUTHERN PLAINS. EXPECT SOME CLEARING LATE IN THE SECOND PERIOD WHICH WOULD ALLOW LOWS TO FALL BELOW GUIDANCE WITH READINGS RANGING FROM THE UPPER 20S WEST TO LOW/MID 30S EAST/SOUTHEAST. ETA 850MB TEMPERATURES REBOUND ON SATURDAY/SUNDAY AS THE LOW PRESSURE AREA MOVES INTO THE SOUTHERN PLAINS AND UPPER RIDGE BUILDS EAST. DAYS 4 THROUGH 7...NO CHANGES. $$ .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...WINTER WEATHER ADVISORY THROUGH NOON MDT FOR KIT CARSON AND YUMA COUNTIES. && $$ MWM ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 145 AM CDT FRI APR 30 2004 .DISCUSSION... LATEST SURFACE ANALYSIS DEPICTS COLD FRONT SITUATED IN A NORTHEAST TO SOUTHWEST ORIENTATION...EXTENDING FROM DBQ TO THE LOW OVER THE TX PANHANDLE. 00Z FRI UA RUN ANALYSIS INDICATED 500 MB PERTURBATION IN THE FLOW JUST SOUTHWEST/UPSTREAM OF THE FA. CURRENT RADAR MOSAIC SHOWS ONGOING PRECIP OVER SE SECTIONS OF THE FA...WITH THE LDS CHART SHOWING SOME ISOLD T. IR SAT PICS SHOW COLDEST TOPS EXITING THE EASTERN PORTION OF THE FA WHICH IS WELL ACCOUNTED FOR IN CURRENT GRIDS. HOWEVER SOME COOLING TOPS OBSERVED JUST EAST OF THE BOOTHEEL ASSOCIATED WITH THE SHORT WAVE ENERGY FORECAST BY THE RUC. CURRENT GRIDS REFLECT A CHC TODAY WHICH APPEARS RSNBL ATTM...WHICH IS IN GOOD AGREEMENT WITH MOST MODEL RUNS FROM 00Z THU. FOR TODAY HAVE K INDICES 28 AND SHOWALTERS AROUND 1 TODAY HOWEVER THE ETA GENERATES CAPE NEAR 1K J/KG TODAY WITH LI' FALLING TO -2 VIA 00Z ETA COMPARED TO THE SLIGHTLY WEAKER GFS. THERE WILL BE SOME STABILIZATION OVERNIGHT ALBEIT SLIGHT AND PROBABLY A RESULT OF LOSING DIURNAL AFFECTS. MODELS IN GOOD AGREEMENT WITH FROPA DURING THE DAY SATURDAY. THE FRONTAL BOUNDARY COMBINED WITH THE DIURNAL HEATING AND MODERATE INSTABILITY WILL PROVIDE THE BEST CHC OF TSRA. WITH THE AFOREMENTIONED PARAMETERS ALL COMING TOGETHER CAN NOT RULE OUT SVR TSTMS FOR SATURDAY ALBEIT SLGT AT BEST AS REFLECTED BY LATEST MODEL RUNS. WILL MAINTAIN TIMING AND POPS ON EXITING PRECIP BY 12Z SUN. THEN DRY SUNDAY WITH A RETURN CHANCE SUNDAY NIGHT AS A COLD POOL PASSES OVERHEAD. NOT VERY CONFIDENT OF THE MONDAY CHC'S BUT WILL HOLD OFF CHANGES FOR NOW IN ORDER TO HELP PREVENT ANY FLIP FLOPPING. AS FOR TEMPS MAV/FWC IN RSNBL AGREEMENT AND WILL FOLLOW SUIT IN THE SHORT TERM. MEX SHOWS A SLIGHT WARMING TREND LATE AND WILL FOLLOW. DIDNT REALLY LIKE TEMPS INTO THE 30S IN FRONTS WAKE...CONSIDERING STRENGTH OF FRONT AND NORMAL IN THE 50S. THUS WILL EMBRACE WARMER SOLUTION. THANKS FOR COORD CALL SGF...LZK...TSA...ICT && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. KY...NONE. MO...NONE. && $$ KH ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 415 AM EDT FRI APR 30 2004 .SHORT TERM... EXTREMELY TRICKY SHORT TERM FCST SINCE FRONTAL TIMING WILL OBVIOUSLY HAVE A HUGE IMPACT ON TEMPS AND WX ACROSS OUR CWA THE NEXT TWO DAYS. AT 06Z THE COLD FRONT EXTENDS FROM ROUGHLY OSC-CAD-LDM-MKE. WE BELIEVE THE FRONT WILL BE AIDED BY COLD DENSE AIR OVER LAKE MI AND PUSH ALL THE WAY SOUTH THE LENGTH OF LAKE MI TO NEAR BEH LATER THIS MORNING. HOWEVER, OUT OVER LAND, THIS FRONT IS ALREADY SLOWING DOWN AND WILL STALL OUT AS IT BECOMES PARALLEL TO WIND FIELDS WITH HEIGHT. THERE IS NO STRONG HIGH TO THE NW OF THIS FRONT OR IMPRESSIVE PRESSURE RISES TO IMPLY THE FRONT WILL MAKE PROGRESS FARTHER SE. 00Z ETA AND GFS IS A BIT FAST WITH FRONTAL MOVEMENT SE ACROSS OUR AREA. WE PREFER THE SLOWER 10 KM HI-RES RUC FRONTAL TIMING WHICH IS MORE IN LINE WITH REGIONAL CANADIAN GUIDANCE. THEREFORE, WE BELIEVE TEMPS WILL BE SNEAKY WARM ACROSS MUCH OF OUR AREA. AFTER LINGERING SCATTERED RAIN SHOWERS THROUGH MID MORNING, WE BELIEVE MOST OF THE DAY WILL BE DRY (THOUGH WE'LL STILL CARRY LOW CHC POPS FOR CONVECTION ALONG AND SE OF BOUNDARY) AS WE GET INTO NVA AS THE UPPER LEVEL DISTURBANCE THAT IS TRIGGERING THE LIGHT SHOWERS ACROSS SOUTHERN MI/NORTHERN IL AND IN MOVES EAST. OUR GUT FEEL IS WE WILL EVEN GET BREAKS OF SUN THROUGH A BKN MID TO HIGH DECK THIS AFTN. LARGE VARIATION IN MAX TEMPS. WE'LL GO WITH MAXES IN THE 50'S ACROSS OUR FAR NORTHERN CWA, TO THE UPPER 60'S TO LOWER TO MID 70'S ACROSS THE REST OF OUR CWA (EXCEPT RIGHT ALONG LAKE MI). THE FRONT WILL LIKELY EXTEND FROM AROUND SAGINAW BAY SW TO NEAR ORD TONIGHT AS A PRETTY SIGNIFICANT LOW PRESSURE WAVE TRACKS NE ALONG IT. GFS TIME HEIGHT RH X-SECTIONS SHOW DEEP MOISTURE AND 4-5 MICROBAR/SEC TYPE LIFT FROM 500 TO 850 MB. THE RUC SHOWS DECENT PCPN MOVING IN HERE TOO. SO, WE'LL GO WITH LIKELY POPS FOR SHOWERS AND TSTORMS. THOUGH WE'LL LOSE INSTABILITY FROM DAYTIME HEATING, TT'S REACH THE UPPER 40'S WITH K-INDEX VALUES IN LOW TO MID 30'S, SO WE THINK IT IS WISE TO MENTION TSTORMS TOO TONIGHT. ON SATURDAY, BELIEVE THE GFS IS STILL A BIT TOO FAR SE WITH THE BOUNDARY. WE'LL GO WITH A CHC FOR SHOWERS AND TSTORMS ALONG THE BOUNDARY, BUT MUCH OF THE DAY SHOULD BE DRY. A BETTER CHC FOR RAIN WILL COME SATURDAY NIGHT AS ANOTHER STRONG LOW PRESSURE WAVE TRACKS NE ALONG THE BOUNDARY. ONCE AGAIN, SINCE WE DON'T THINK THE BOUNDARY WILL BE QUITE AS FAR SE AS THE GFS SHOWS,LIKELY POPS ARE NECESSARY FOR OUR SE CWA WITH CHC POPS ELSEWHERE. LOW LEVEL CRIT THICKNESS PROGS SUGGEST PCPN ACROSS OUR NORTHERN/NW CWA SAT NIGHT WILL BE ALL LIQUID. THE BOUNDARY WILL FINALLY MOVE EAST OF OUR AREA SUNDAY AS THE SHARP H5 TROUGH AXIS MOVES OVERHEAD AND VIGOROUS UPPER LEVEL ENERGY PASSES THROUGH. IT WILL BE CLOUDY, UNSEASONABLY COOL, AND WE'LL HAVE SCATTERED SHOWERS THAT MAY MIX WITH SNOW ACROSS OUR NORTHERN CWA! BY SUNDAY NIGHT, WE'LL ALLOW CONDITIONS TO DRY OUT LATE AS A SFC HIGH PRESSURE RIDGE BUILDS IN AND MOISTURE DECREASES. MAY HAVE SOME FROST/FREEZE ISSUES TO DEAL WITH COME EARLY MONDAY MORNING. .LONG TERM... THE OVERALL TREND FROM MONDAY THROUGH SATURDAY WILL BE FOR A WARMING TREND. THIS IS WELL SUPPORTED BY THE ECMWF...CANADIAN AND GFS MODELS AND THE CONTINUITY OF THOSE MODELS. TO SAY NOTHING OF THE ENSEMBLE OF THE GFS AND CANADIAN WHICH ALSO SUPPORT THIS IDEA. THE SHARP COLD TROUGH WILL BE QUICKLY BOOTED OUT MONDAY BY THE NEXT LARGE PACIFIC SYSTEM THAT WILL MOVE ONSHORE IN BC SUNDAY. THE SYSTEM ASSOCIATED WITH THAT WAVE WILL MOVE THROUGH THE GREAT LAKES TUESDAY INTO WEDNESDAY AND MAY BRING SOME SLIGHTLY COOLER AIR WITH IT. COULD BE SOME SHOWERS AT SOME POINT BETWEEN TUESDAY AND WEDNESDAY WITH THAT NEXT WAVE...BUT MOST OF DYNAMICS ARE NORTH OF OUR CWA AT THIS POINT AND THERE IS SOME TIMING ISSUES. SO I DID NOT PUT IT IN THE GRIDS FOR NOW BUT WE MAY HAVE TO ADD SHOWERS FOR TUESDAY/WEDNESDAY AS WE GET CLOSER TO THOSE DAYS. DRY AS HIGH PRESSURE FOLLOWS THAT SHORTWAVE FOR LATER WEDNESDAY AND THURSDAY. BY THE END OF THE WEEK AN EVEN MORE POWERFUL PACIFIC STORM NEAR THE WEST COAST WILL BUILD A RIDGE OVER THE CENTRAL U.S. AND THAT WILL BRING THE WARMEST AIR OF THE SEASON FOR NEXT WEEKEND. I COULD SEE MID 80S WITH LITTLE PROBLEM! GIVEN OUR OVERWHELMING TREND OF FORECASTING HIGHS TO COLD BEYOND DAY 3...I WENT ALONG WITH OUR PREVIOUS GRIDS FOR TUESDAY THROUGH THURSDAY AND IN ADDING THE GRIDS FOR FRIDAY INTO SUNDAY PUSHED HIGHS WELL INTO THE 80S. GIVEN THAT...I HAVE SCT THUNDERSTORMS EACH DAY. && .GRR...WATCHES/WARNINGS/ADVISORIES...NONE. && LAURENS WDM mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 350 AM EDT FRI APR 30 2004 .DISCUSSION... 00Z RAOBS/LATEST WV LOOP AND RUC ANALYSIS SHOW ACTIVE SPLIT FLOW ACRS NAMERICA...WITH NRN BRANCH UPR TROF CENTERED OVER CNTRL CAN. BULK OF DEEP MSTR CAUGHT UP IN SRN BRANCH...WHICH FEATURES A CUTOFF LO OVER THE SRN ROCKIES AND A PERSISTENT RDG ALG THE SE COAST. FA UNDER WSW FLOW NEAR UPR CONFLUENCE ZN BTWN ERN SIDE OF CNTRL CNDN TROF AND NW FLANK OF SRN BRANCH RDG IN THE SE. SHALLOW COOL AIR HAS OVERSPEAD THE UPR GRT LKS ON THE SRN FLANK OF SFC HI PRES RDG STRETCHING FM ONTARIO INTO THE NCNTRL PLAINS. SFC FNT ON THE SRN EDGE OF THIS COOL AIR STRETCHES FM ERN KS-IA-SRN WI-NRN LWR MI...BUT H85 FNT DRAPED WSW-ENE ACRS THE CWA. INTERACTION BTWN THIS FNT AND ASSOCIATED FRONTOGENESIS...SHRTWV NR INL/RRQ OF 120KT H3 JET MAX OVER ONTARIO/ASSOCIATED UPR DVGC...AND NRN EDGE OF HIER PWAT TO THE S (00Z PWAT AT GRB 0.93 INCH...180 PCT OF NORMAL) HAS RESULTED IN BANDS OF PCPN INTO EARLY THIS MRNG OVER ALL BUT THE NW CWA...WHERE DRIER LLVL AIR AS DEPICTED ON 00Z YPL SDNG/SFC DWPTS NR 15F IN MN ARROWHEAD HAVE MADE GREATER HEADWAY S. MAJORITY OF PCPN IN THE FORM OF RA...BUT SOME SN/PL HAS MIXED IN OVER HIER TERRAIN AS COLDER/ DRIER AIR TO THE NW FEEDING SE IN LLVL NNW FLOW BEHIND SFC FNT. MORE RECENT RADAR TRENDS INDICATE PCPN IS BEGINNING TO WIND DOWN. ANOTHER STRG SHRTWV/120KT H3 JET MAX NOTED DIGGING SE THRU ALBERTA/ SASKATCHEWAN...AND ASSOCIATED SFC/H85 TROF ALREADY MOVING THRU LK WINNIPEG/NRN PLAINS. MAIN FCST CONCERNS THIS PACKAGE ARE TIMING OF PCPN EPISODES IN CONTINUED ACTIVE UPR FLOW. ETA HAS HAD GOOD HANDLE ON CURRENT PCPN EPISODE OVER FA...AND MODEL SHOWS H85 FNT/FRONTOGENESIS PUSHING FARTHER S THRU 12Z AS UPR DVGC WEAKENS FOLLOWING DEPARTURE OF ONTARIO JET MAX...WITH H85-5 QVECTOR DVGC/LLVL ACYC FLOW DVLPG AND ADVECTING MUCH DRIER AIR TO THE NW THRU THE U.P. WHETHER OR NOT AND WHERE TO LEAVE SOME SCT -SHRASN EARLY IN THE FCST FOR TDAY WL DEPEND ON RADAR DEPICTION AT FCST ISSUANCE. SKIES MOCLR TO THE NW...BUT LOOKS LIKE CONSIDERABLE HI/MID CLD WL LINGER OVER MUCH OF THE FA AS FLOW ALF REMAINS MORE WSW IN RESPONSE TO DIGGING SHRWTV NOW OVER ALBERTA. BEST CHC FOR BRIGHTER SKIES WL BE OVER THE NW ZNS CLOSER TO THE LOWER PWAT TO THE NW. GIVEN INTENSE LOOK OF SHRTWV ON WV IMAGERY/RAOBS...PREFER ETA FCST OF STRONGER SYS AND LOWER PRES THIS MODEL DVLPS NR YQT BY 00Z. BUT DESPITE SOME IMPRESSIVE DPVA/ H85-5 QVECTOR CNVGC LATE IN THE DAY OVER THE WRN ZNS...PRIOR ARRIVAL OF DEEPER DRY AIR/ACYC FLOW BEHIND DEPARTING SYS THIS MRNG RESULTS IN AN AIRMASS TOO PROHIBITIVELY DRY TO SUPPORT PCPN PER ETA FCST SDNGS...ESPECIALLY CONSIDERING SFC TROF REMAINS TO THE W. SO REST OF DAY WL BE DRY ONCE LINGERING PCPN LEAVES THIS MRNG. TEMPS WL BE WELL BLO NORMAL UNDER MID/HI CLD AND WITH ARRIVAL OF SFC-H85 THERMAL TROF. EXPECT THE HIEST TMAX NR IWD...WHERE SUNSHINE WL BE LESS FILTERED AND LLVL FLOW TURNS MORE TO THE S LATE...AND LOWEST READINGS NR LK SUP WHERE LGT NE FLOW WL PERSIST MOST OF THE DAY. FOR TNGT...ETA/GFS SHOW SHRTWV TENDING TO SHEAR OUT AS IT ENTERS MORE CONFLUENT SW FLOW/LIFTS NEWD THRU WRN LK SUP TNGT...WITH SFC TROF PASSING THRU FA BUT TENDING TO WEAKEN WITH TIME UNDER THE UPR CONFLUENCE. ALTHOUGH SFC TROF IS STRONGER WHEN IT ENTERS THE WRN ZNS IN THE EVNG...MODELS ADVERTISE MORE QPF OVER THE SE ZNS CLOSER TO DEPARTING FNT/HIER PWAT. IN GENERAL...GFS MORE AGGRESSIVE WITH QPF THAN ETA AND TENDS TO GET MORE SRN BRANCH PHASING...BUT PREFER DRIER ETA AS BOTH MODELS SHOW SHARPER THERMAL GRADIENT/FRONTOGENESIS STAYING SE OF FA WITH LLVL DRY ADVCTN AND WEAK ISENTROPIC DESCENT ON 280K-290K SFCS (H9-7). SINCE ETA ALSO SEEMS TO HAVE A BETTER HANDLE ON THE STRENGTH OF THE NRN BRANCH SHRTWV...ITS SOLN OF MORE OF JUST A NRN BRANCH SYS WOULD SEEM MORE APPROPRIATE. EITHER WAY...GOING FCST LIKELY POPS ACRS THE SE/CHC ELSEHWERE STILL SEEM APPROPRIATE. PCPN TYPE A CONCERN AS WELL...BUT WL GO WITH MAINLY RA AS ETA FCST SDNGS SHOW LLVL AIRMASS BECMG QUITE UNSTABLE THIS AFTN AND DEPTH OF WBLB > 0 A FEW THOUSAND FEET DEEP TNGT...AT LEAST UNTIL SFC TROF PASSES THRU THE WRN ZNS LATE AT TNGT AND COLDER AIR (H100-85 THKNS BLO 1300M) FLOWS INTO FA IN ITS WAKE. GFS FCST H85 TEMPS EVEN HIER THAN ETA...SO WL FCST ONLY RA UNTIL LATE AT NGT OVER THE W WHERE UPSLOPE NW FLOW WL GENERATE SCT -SHRASN EVEN AFTER DEEPER MSTR/ DYNAMICS DEPART. GFS/ETA SHOW MUCH DRIER AIR (PWAT AOB 0.25 INCH) ARRIVING DURING THE DAY ON SAT AS NRN BRANCH TROF PUSHES OVER MN AND SHRTWV CONTINUES SHEARING OUT IN THE SW FLOW AHEAD OF THE MAIN TROF AND A STEADY WNW FLOW IN THE WAKE OF THIS SYS PUSHES COLDER AIR SE AS WELL. WL CARRY SOME MRNG POPS...THEN DRY. ETA FCST SDNGS SHOW CONSIDERABLE LLVL DRYING DURING THE DAY...ESPECIALLY OVER THE DOWNSLOPE SE ZNS...BUT GFS IS MORE STUBBORN TO HANG ON TO THE LLVL MSTR EVEN UNDER THE DRYING ALF. SINCE PREFERRED ETA SHOWS NRN BRANCH SHRTWV DOMINATING OVER THE SRN BRANCH...WL GO WITH MORE OF A DRIER NW FLOW VS THE MOISTER NNW FLOW DEPICTED BY THE GFS (AND NGM) THAT MIGHT BE THE CASE WITH A MORE SRN BRANCH FLAVOR TO THE FCST. CONCERNED ABOUT SOME INSTABILITY -SHRASN OVER THE HIER TERRAIN OF THE NW...BUT ETA FCST SDNGS SHOW SUBSIDENCE INVRN ARND H85 PROHIBITIVELY LO FOR -SHRA... BUT IDEAL FOR SC LINGERING LONGER OVER THE HIER TERRAIN. FCST H85 TEMPS IN THE -4C (SE) TO -7C (NW) RANGE SUPPORT TMAX ARND 50 OVER THE SE TO 40 TO 45 OVER THE HIER TERRAIN OF THE NW. BOTH GFS/ETA IN GOOD AGREEMENT SHOWING CORE OF DRIER AIR REMAINING OVER ALL THE CWA...EXCEPT THE FAR E. SINCE THE GFS IS SLOWER WITH THE PROGRESSION OF THE UPR TROF AXIS WITH MORE PHASING BTWN THE NRN/SRN BRANCHES (ALTHOUGH IT IS TRENDING FASTER AT MOVING THE TROF WITH LESS PHASING)...IT SHOWS SOMEWHAT DEEPER MSTR BLDG BACK INTO THE ERN ZNS AS MORE IMPULSES RIDE NEWD IN THE SW FLOW OF THE UPR TROF AND MAINTAIN MORE CYC FLOW. HAVE OPTED TO REMOVE PCPN FM ALL THE FA SAT NGT-SUN NGT EXCEPT THE ERN ZNS...AS CNDN MODEL A BIT MORE SLUGGISH PUSHING PCPN OUT OF THE FA AS WELL. COORDINATED WITH APX. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MIDLAND/ODESSA TX 500 AM CDT FRI APR 30 2004 .SHORT TERM... STRONG SURFACE COLD FRONT IS CURRENTLY JUST SOUTH OF KLBB WITH EXTENSIVE LOW CLOUDS AND TEMPERATURES IN THE 40S F NOTED BEHIND THE FRONT IN THE PANHANDLE. ADDITIONAL SURFACE FEATURES ACROSS THE AREA INCLUDE A LOW NEAR LOVINGTON NM AND A DRYLINE LOCATED ALONG A PLAINS...WINK...FORT STOCKTON LINE. THE MAJORITY OF THE SHORT RANGE MODELS ARE TOO SLOW WITH THE SOUTHWARD PROGRESSION OF THE COLD FRONT...HOWEVER THE LATEST ETA AND RUC ARE TRENDING IN THE RIGHT DIRECTION. SURFACE HEATING AND WESTERLY LOW-LEVEL FLOW AHEAD OF THE FRONT MAY SLOW THE IT/S PROGRESS...BUT GIVEN THE COLD AIRMASS BEHIND THE FRONT...HAVE OPTED TO SPEED UP THE FRONTAL PASSAGE ACROSS THE AREA. LOW POPS WERE ALSO ADDED TO THE GRIDS ACROSS THE EASTERN 1/3 OF THE CWA TODAY AS THE COLD FRONT MAY ENCOUNTER ENOUGH LOW-LEVEL MOISTURE FOR ISOLATED THUNDERSTORMS. THE CURRENT HIGH WIND WARNING FOR THE GUADALUPE MOUNTAINS WILL REMAIN IN EFFECT AS ETA CROSS SECTIONS STILL SUGGEST A MOUNTAIN WAVE SIGNATURE. CLOUDS WILL INCREASE BEHIND THE COLD FRONT TONIGHT AND WITH STRONG CAA... TEMPERATURES WERE LOWERED. MOS GUIDANCE FOR GUADALUPE PASS SUGGESTS SUSTAINED WINDS WILL BE NEAR WARNING CRITERIA IMMEDIATELY BEHIND THE COLD FRONT. WE WILL NOT ISSUE A WARNING NOW DUE TO SHORT RANGE MODELS NOT HANDLING THE CURRENT SITUATION...BUT WINDS WERE INCREASED AND LATER SHIFTS WILL NEED TO MONITOR. .LONG TERM... THE LONG TERM PORTION OF THE FORECAST WILL FOCUS ON THE EFFECTS OF THE STRONG FRONTAL PASSAGE LATE FRIDAY/EARLY SATURDAY. POST FRONTAL CONDITIONS SATURDAY AND SUNDAY ACROSS THE FA WILL BE CHARACTERISTIC OF THE CLIMATOLOGICAL WEST TEXAS BLACKBERRY WINTER...A PHRASE USED BY FORECASTERS IN AMARILLO TO DESCRIBE THE NEAR-ANNUAL STRONG COLD FRONT THAT AFFECTS THE REGION AROUND THE FIRST WEEK OF MAY. BY 12Z SATURDAY THE MID/UPPER LOW WILL BE OPENING AND EVER SO SLOWLY PROPAGATING EAST OVER THE SOUTHERN ROCKIES. THE STRONG FRONTAL BOUNDARY WILL LIKELY HAVE SWEPT SOUTH ACROSS MOST OF THE AREA... LEAVING BREEZY/CAA IN ITS WAKE. WITH THE TROUGH AXIS STILL JUST WEST OF THE AREA...WEAK ISENTROPIC UPGLIDE IS PROGGED TO MOISTEN THE 800-500 MB LAYER NORTH OF THE SURFACE FRONT IN RESPONSE/PROXIMITY TO ZONE OF DPVA. THIS IS DEPICTED IN MESOETA FORECAST SOUNDINGS FOR THE CENTRAL BASIN. GIVEN STEEP MID LEVEL LAPSE RATES ASSOCIATED WITH APPROACHING COLD POOL...ELEVATED CONVECTION WILL BE POSSIBLE. WILL DRAW SLIGHT CHANCE GRIDDED POPS OVER THE EAST/SOUTHEAST FA EARLY SATURDAY...WITH RAIN CHANCES DECREASING/SHIFTING SOUTHEAST THROUGH THE DAY AS BEST DPVA/FORCING INCHES EAST AND SHIFTS OUT OF PHASE WITH THE LOW LEVEL BOUNDARY. HIGH WINDS WILL ALSO BE POSSIBLE THROUGH MIDDAY SATURDAY AT GUADALUPE PASS AS THE FRONT/PRESSURE GRADIENT INTERACTS WITH THE MOUNTAIN BARRIER AND PROMOTES GAP WINDS. MID/UPPER TROUGH AXIS WILL FINALLY BE MOVING EAST OF THE FA BY 12Z SUNDAY. IN ITS WAKE...SURFACE HIGH IS PROGGED TO RESIDE OVER THE AREA. LIGHT WINDS AND MOSTLY CLEAR SKIES IN SUBSIDENT REGION OF LARGE SCALE TROUGH SHOULD PROMOTE RADIATIONAL COOLING AND MINIMA TEMPERATURES SOME 10 TO 12 DEGREES BELOW SEASONAL NORMS SUNDAY. THE REMAINDER OF THE LONG TERM WILL BE HIGHLIGHTED BY BENIGN WEATHER AS A RIDGE BUILDS OVER THE SOUTHWEST. TEMPERATURES WILL MODERATE BY MID WEEK WITH MAXIMA WEDNESDAY APPROACHING 90F AS HEIGHTS INCREASE OVER THE SOUTHERN ROCKIES. CAN NOT RULE OUT ISOLATED AFTERNOON THUNDER VICINITY OF THE MOUNTAINS EARLY TO MID WEEK...BUT DO NOT SEE EVIDENCE WARRANTING A MENTION OR SPECIFIC DAY ATTM. && .FIRE WEATHER... LOW DEW POINTS AND INCREASING WESTERLY WINDS OVER THE GUADALUPE MOUNTAINS WILL PRODUCE RED FLAG FIRE WEATHER CONDITIONS THROUGH THE EARLY AFTERNOON. THE DURATION OF RED FLAG CONDITIONS WILL LARGELY DEPEND ON THE TIMING OF THE COLD FRONT AND FOR NOW WILL CALL FOR CONDITIONS TO LAST INTO THE EARLY AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... BIG SPRING TX 85 50 65 45 / 20 30 20 0 CARLSBAD NM 83 47 68 43 / 0 20 0 0 DRYDEN TX 88 58 71 46 / 20 30 20 10 FORT STOCKTON TX 88 53 69 46 / 10 20 20 0 GUADALUPE PASS TX 73 41 62 39 / 0 0 0 0 HOBBS NM 79 45 65 41 / 10 20 10 0 MARFA TX 80 44 65 37 / 0 0 10 0 MIDLAND INTL AIRPORT TX 84 50 65 43 / 10 20 20 0 ODESSA TX 86 49 66 41 / 10 20 20 0 WINK TX 91 49 69 41 / 10 20 10 0 && .MAF WATCHES/WARNINGS/ADVISORIES... TX...RED FLAG WARNING GUADALUPE MOUNTAINS TIL 22Z. HIGH WIND WARNING GUADALUPE MOUNTAINS TIL 15Z. NM...RED FLAG WARNING GUADALUPE MOUNTAINS TIL 22Z. HIGH WIND WARNING GUADALUPE MOUNTAINS TIL 15Z. && $$ PLATT/LINDLEY tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 330 AM CDT FRI APR 30 2004 .SHORT TERM...MSAS SURFACE ANALYSIS INDICATED A RELATIVELY STRONG COLD FRONT NOSING ACROSS THE TEXAS PANHANDLE MORNING. CONVECTION CONTINUES TO DEVELOP ALONG THE FRONTAL BOUNDARY DRAPED ACROSS THE SOUTHERN PLAINS AS A 500MB LOW IS MOVING ACROSS THE FOUR CORNERS AREA. WATER VAPOR SATELLITE IMAGES AND RUC 500MB HEIGHT/VORTICITY ANALYSIS INDICATES A COUPLE OF WEAK SHORTWAVES MOVING INTO SOUTHWEST TX AND INTO NORTHEAST MEXICO AHEAD OF THE UPPER LOW OVER THE SOUTHWEST UNITED STATES. THE 00Z GFS MODEL INDICATES SOME CONVECTION DEVELOPING OVER THE WESTERN CWA THIS MORNING WITH SOME 700MB VERTICAL MOTION. THEREFORE...WILL MENTION SOME ISOLATED SHOWERS AND THUNDERSTORMS FOR THE WESTERN ZONES/GRIDS THIS MORNING. HOWEVER...NOT BUYING AFTERNOON CONVECTION WITH THE GFS SO WILL LEAN TOWARDS THE DRIER 00Z ETA. MODELS APPEAR TO AGREE ON TIMING OF THE COLD FRONT MOVING INTO CENTRAL TX TONIGHT WITH STRONG CONVECTION DEVELOPING ACROSS SOUTHWEST TX LATE TONIGHT AS THE 500MB LOW OVER THE FOUR CORNERS REGION MOVES INTO WEST TX AS A TROUGH. WILL INTRODUCE POPS LATE TONIGHT AND INCREASE SATURDAY AFTERNOON AS THE FRONT MOVES INTO SOUTH TX. BEST RAIN CHANCES APPEAR LATE SAT AFTERNOON INTO EVENING AS THE FRONT MOVES INTO DEEP SOUTH TX. GFS STILL PROGGING AN MCS TO DEVELOP SAT NIGHT AS UPPER LEVEL DIFFLUENCE INCREASES. WILL CONTINUE MENTION OF SEVERE WEATHER WITH HEAVY RAINFALL POSSIBLE. RAIN CHANCES SHOULD DIMINISH TOWARDS SUNDAY MORNING AS COLD FRONT MOVES OFFSHORE THE LOWER TX COAST. && .LONG TERM...CLEARING TREND SHOULD CONTINUE AS UPPER TROUGH OVER THE CENTRAL U.S. MOVES EASTWARD. HIGH PRESSURE TO BUILD INTO TEXAS SUNDAY WITH DRIER AND SLIGHTLY COOLER AIR. TEMPERATURES WILL WARM THROUGH THURSDAY AS THE SURFACE RIDGE OVER SOUTH TX MONDAY MOVES EASTWARD ALLOWING RETURN FLOW TO DEVELOP TUESDAY. WITH THE INCREASE IN MOISTURE CLOUDS WILL RETURN LATE TUESDAY. && .MARINE...WEAK SE FLOW THU RESULTED IN SEAS FM 3 TO 5 FT. RIGHT NOW...BUOY 020 REPORTS SE WNDS AROUND 10 KTS WITH 4 FEET SEAS AT 7 SECS. LATEST WAVE WATCH (GWW) MAINTAINS 3 TO 5 FEET SEAS TDY...5 TO 7 BY SAT PM...AS SE FLOW INCREASES TO 20 TO 25 KTS AHEAD OF AN APPROACHING CF. FROPA TIMING...AND PLACEMENT AND INTENSITY OF THE CONVECTION ASSOCIATED WITH THIS FEATURE ARE IN AGREEMENT BY ETA/GFS NOW. XPCT FROPA NEAR MIDNIGHT SAT...WITH NORTH WNDS AT 25 TO 35 KTS POSSIBLE. SVR TSTM DEVELOPMENT BECMG MORE LIKELY WITH TIME...AND MARINERS SHUD CONTINUE TO MONITOR THE INTENSITY OF THIS WX FEATURE SAT AND SUN. AVN KICKS OUT 40 KTS OF NORTH WND JUST OFF THE CAMERON COUNTY COAST AT 1 AM SUN...WITH GWW BUILDING SEAS TO 8 TO 10 FEET SOON AFTER FROPA. HIGH PRESSURE BUILDS INTO THE REGION SUN PM THRU WED. && .AVIATION...CIGS 1K TO 2K FT THIS AM. VFR CONDITIONS BY MID MRNG...FOLLOWED BY CIGS 1K TO 2K FT SAT AM. WNDS SE 20 TO 25 MPH TDY AND SAT. SCT TO NUMEROUS 1SM +TSRA VRB25G35KTS XPCTD LATE SAT PM THRU EARLY SUN...AS FROPA SHIFTS WNDS NW 15G25KTS BY MIDNIGHT SAT. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 84 76 83 66 77/ 00 10 60 60 00 BROWNSVILLE 86 75 85 65 79/ 00 10 60 60 00 HARLINGEN 87 74 86 64 78/ 00 10 60 60 00 MCALLEN 89 73 87 64 79/ 00 10 60 50 00 RIO GRANDE CITY 90 71 88 62 78/ 10 20 60 50 00 SOUTH PADRE ISLAND 83 76 82 66 76/ 00 10 60 60 00 && .BRO WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPTIC/GRIDS...61 MARINE/AVIATION/MESO...58 THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 200 AM CDT FRI APR 30 2004 .SYNOPSIS... WATER VAPOR/HEIGHT ANALYSIS THROUGH 06Z SHOWING THE POLAR VORTEX OVER THE NORTHERN PORTION HUDSON BAY. A LONGWAVE TROUGH EXTENDS FROM THIS FEATURE SOUTH INTO THE NORTH-CENTRAL UNITED STATES. A SECOND LOW OF INTEREST IS CLOSED OFF AND CENTERED OVER THE 4 CORNERS REGION AT 06Z. DISTURBANCES FROM THE LONGWAVE TROUGH ARE ROUNDING THE BASE OF THE TROUGH THROUGH THE DAKOTAS AND MOVING THROUGH THE REGION. THIS IS WHAT IS RESPONSIBLE FOR THE SHOWER ACTIVITY OVER NORTHERN WISCONSIN. THE SECOND LOW IS EJECTING WEAK DISTURBANCES NORTHEAST INTO THE MEAN FLOW. THIS IS WHAT WILL HAPPEN TODAY...CAUSING PRECIPITATION ACROSS THE REGION. AT THE SURFACE...LOW PRESSURE WAS CENTERED ABOUT 50 MILES SOUTH OF THE DELLS. THIS WAS MOVING NORTHEAST ALONG A COLD FRONT...WHICH HAS SLOWED CONSIDERABLY AND WILL BECOME STATIONARY...EXTENDING FROM NEAR A KMKE-KMRJ-KDSM LINE. THIS MEANS THAT A VERY SMALL PORTION OF GRANT COUNTY REMAINS AHEAD OF THE FRONT. && .DISCUSSION... UPPER LEVEL TROUGH WILL PROGRESS SLOWLY EAST THROUGH TIME. THEREFORE...MAIN FORECAST CHALLENGE IS DISTURBANCE MOVING NORTHEAST THROUGH THE REGION LATER TODAY/TONIGHT AND HOW COLD IT WILL GET BEHIND THE FRONT. ETA/GFS IN GENERAL AGREEMENT WITH THE SYNOPTIC SCALE FEATURES. MAIN DIFFERENCE IS THE AMOUNT OF PRECIPITATION THAT IS PRODUCED TONIGHT. THE HIGHER QPF PRODUCED BY THE GFS AGREES WITH THE RUC...WHICH HAS USUALLY BEEN THE CASE WITH SYSTEMS MOVING NORTHEAST THROUGH THE REGION FOR THE PAST 6 MONTHS. THE GFS/RUC OUTPERFORM THE ETA IN THESE CASES. THIS SHOULD BE NO DIFFERENT. FOR THE REMAINDER OF THE MORNING...LIGHT PRECIPITATION WILL CONTINUE ACROSS THE NORTHERN COUNTIES. LATER TODAY...THE FORCING ASSOCIATED WITH EJECTING DISTURBANCE WILL MOVE THOROUGH THE REGION. THE FRONTOGENESIS IS ALIGNED PARALLEL WITH THE STORMS MOTION...SO EXPECT A PROLONGED PRECIPITATION TO OCCUR. THINK THE BEST CHANCE FOR THIS IS FROM 30/18-01/06Z TONIGHT. ONCE THIS SYSTEM MOVES THROUGH...COOLER AIR WILL MOVE INTO THE REGION. THIS WILL OCCUR BY 01/12Z SATURDAY. THICKNESS AND 850 MB TEMPERATURES CONTINUE TO FALL ALL THE WAY INTO SUNDAY AS HIGH PRESSURE MOVES IN. WITH 850 MB TEMPERATURES OF -6 TO -7 AND 1000- 500 MB THICKNESS OF 525-528 DAM...THINK TEMPERATURES WILL BE LOWER THAN MOS. FROST/FREEZE HEADLINES WILL BEGIN FOR OUR FORECAST AREA MAY 1ST... WITH THE EXCEPTION OF TAYLOR/CLARK/JACKSON/MONROE/ADAMS/JUNEAU COUNTIES WHICH BEGIN MAY 10TH. THEREFORE...WE WILL HAVE TO MONITOR THE LOWS FOR POSSIBLE HEADLINES. && .ARX...WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...NONE. WI...NONE && $$ KRC wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 949 AM MDT FRI APR 30 2004 .UPDATE... TRACK OF THE UPPER LOW APPEARS TO BE SLIGHTLY TOO FAR NORTH TO MAINTAIN STEADY PRECIP ACROSS THE AREA TODAY. UPSLOPE AND ISENTROPIC UPGLIDE CONTINUE TO DIMINISH...WITH 12Z RUC/ETA SHOWING ONLY A TENTH OF AN INCH OR LESS IN THE WAY OF QPF THROUGH THIS EVENING. WILL LIKELY SEE SOME -SHSN/-SHRA ACTIVITY OVER THE AREA TODAY WITH COLD TEMPS ALOFT...AND COULD STILL SEE SOME ACCUMULATING SNOW MAINLY CENTRAL AND WESTERN MTN ZONES. WILL DO AN EXTENSIVE UPDATE TO THE ZONES...GOING WITH JUST SCATTERED SHOWERS AND MINIMAL SNOW ACCUMS OVER THE EAST...WITH PERHAPS ANOTHER 2-4 INCHES CENTRAL AND WESTERN MTS. WILL BE DROPPING HEADLINES OVER THE ERN MTS WITH THE UPDATED FCST/GRIDS...AND DOWNGRADING WINTER STORM WARNING TO A WINTER WEATHER ADVISORY OVER THE CENTRAL ZONES...WHICH SHOULD HOPEFULLY BE ISSUED BY 1030 AM MDT. --PETERSEN && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY...COLLEGIATE/MOSQUITO MT RANGES (058/060/061/063) UNTIL 5PM THIS AFTERNOON. WINTER WEATHER ADVISORY...UPPER ARK RIVER VALLEY/WAUGH MTN (059/062/076/077/078)...ERN SAN JUAN/LA GARITA MTS (068/066) UNTIL 5PM THIS AFTERNOON. .PREVIOUS DISCUSSION 345 AM... .SHORT TERM... (TODAY AND TONIGHT) ...POTENTIAL FOR SOME WELL NEEDED PRECIPITATION TODAY... CURRENTLY: IR/WV SATELLITE IMAGERY AND H5 RUC ANALYSIS INDICATED THAT THE UPPER LOW PRES SYSTEM WAS OVER THE FOUR CORNERS EARLY FRI MORNING...WITH WIDESPREAD RAIN AND SNOW RACING NORTH ACROSS THE CWA. LTG PLOTS ALSO INDICATED SOME ISOLATED LTG STRIKES ACROSS THE FAR SE CORNER OF THE STATE. THERE WAS A LARGE AREA OF DRIER AIR MOVING UP ACROSS NORTHERN NM AND INTO CO...BUT MOISTURE WAS WRAPPING AROUND THE LOW AND THERE WAS ACTUALLY SOME ENHANCEMENT DEVELOPING JUST SOUTH OF THE SANGRES...SO PRECIP SHOULD CONTINUE AFTER A POSSIBLE BRIEF LULL EARLY. TODAY: TOUGH FORECAST TODAY AS SLIGHT VARIATIONS IN THE TRACK OF THE UPPER LOW WILL EQUATE TO BIG DIFFERENCES IN PRECIP AMOUNT AND TYPE OUTCOME. BOTH ETA AND GFS MOVE THE UPPER LOW EAST ACROSS THE CO/NM BORDER EARLY THIS MORNING...THEN BY THE AFTN DROPS IT TO THE SE AS THE LOW OPENS UP. AS MENTIONED...AN AREA OF DRIER AIR WAS TRYING TO EDGE UP INTO THE REGION...PUSHING THE ONGOING PRECIP NORTH UP AGAINST THE PALMER DIVIDE. THIS IS DEPICTED BY MODEL PRECIP CHARTS...WITH FOCUS AREA RESTING ON THE PIKES PEAK AND N EL PASO COUNTY AREA...THEN SHIFTING OVER TO THE CENT MTS. AS THE LOW MOVES EAST THIS AM...HEALTHY UPSLOPE FLOW AND 300K ISENTROPIC UPGLIDE BECOMES MORE SOUTHERLY/PARALLEL...WHICH REINFORCES PUSHING THE PRECIP NORTH. BUT...PRECIP CHARTS DIFFER ON EXTENT OF COVERAGE TODAY...AND DO NOT THINK CHANGING MUCH FOR THE FIRST PERIOD WOULD BE PRUDENT. DECIDED TO CONTINUE THE VARIOUS ONGOING ADVISORIES AND WARNINGS...BUT IF THE EXPECTED REDEVELOPMENT OF PRECIP DOES NOT TAKE PLACE BY LATE MORNING THEN THE HIGHLIGHTS MIGHT BE TAKEN DOWN. WITH A BRIEF LULL IN THE PRECIP EXPECTED...MAX TEMPS SHOULD CREEP UP INTO THE LOWER 40S...BUT STILL NOT MUCH OF A DIURNAL SWING TODAY. ALSO ADDED ISOLATED THUNDER FOR BACA AND PROWERS COUNTIES TODAY DUE TO ONGOING CONVECTION IN THE VICINITY THIS MORNING...AND BETTER LAPSE RATES FOR THE SE CORNER. TONIGHT: THE UPPER TROUGH MOVES ACROSS SE CO INTO THE OK AND TX PANHANDLES...WITH A VORT BAND HANGING BACK ACROSS S CENT NM. THE FLOW BECOMES MORE NW WHICH SHOULD EFFECTIVELY SHUT OFF MOST OF THE PRECIP. PAINTED MOST OF THE AREA WITH ISOLATED POPS AROUND THE MIDNIGHT TIME FRAME...THEN DRY PRIOR TO SUNRISE. JUST SOME SLIGHT ADJUSTMENTS TO MIN T GRIDS WITH LATEST NUMERICAL GUIDANCE...AND LITTLE CHANGE NEEDED TO ONGOING WINDS/SKY COVER. \\MOORE// .LONG TERM... (SATURDAY THROUGH SUNDAY) ...QUIET WEATHER... NOT MUCH TO WRITE ABOUT THIS MORNING AS GUIDANCE CONTINUES TO INDICATE WX DURING THIS PERIOD WILL REMAIN DRY. PRECIP ASSOCIATED WITH ONGOING EVENT SHOULD COMPLETELY MOVE OUT BY 12Z SAT. TEMPS WILL REBOUND SAT INTO THE 50S AND 60S PLAINS...WITH 60S AND 70S BY SUNDAY. AREAS OF HVYR SNOW WHICH WE ARE GETTING MAY PLAY INTO HIGHS SAT BUT WILL HAVE TO WAIT FOR REPORTS/VIS SAT PIX TO GET FEEL FOR WHERE MOST OF IT FELL. FOR THE REST OF THE WEEK...RIDGE ALOFT OVER AREA. RIDGE NOT AS HIGH IN AMPLITUDE AS PREVIOUS RUNS...BUT STILL WE SEE TEMPS WARM INTO THE 80S MOST PLAINS FOR THE WEEK. NO SIGNIF WX SEEN ON THE HORIZON. \/HODANISH && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING...COLLEGIATE/MOSQUITO MT RANGES (058/060/061/ 063)...TELLER COUNTY (081/082)...WET MTS (079/080)...AND SANGRE DE CRISTO MTS (072>075) UNTIL 5PM THIS AFTERNOON. WINTER WEATHER ADVISORY...MID AND UPPER AR RIVER VALLEYS (059/062/077/078)...ERN SAN JUAN/LA GARITA MTS (068/066)...SOUTHERN FOOTHILLS (087/088)...AND NRN EL PASO COUNTY (084) UNTIL 5PM THIS AFTERNOON. && $$ co AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE GOODLAND KS 759 AM MDT FRI APR 30 2004 .DISCUSSION...WILL BE UPDATING THE ZONES MAINLY TO ADJUST PRECIPITATION CHANCE AND PHASE. FIRST BAND GOING THROUGH NORTHERN AND EASTERN SECTIONS AT THIS TIME. LIGHT SNOWFALL RIGHT NOW SEEMS TO BE CONFINED TO NORTHERN YUMA...DUNDY...AND HITCHCOCK. MEASURABLE PRECIPITATION LOOKS TO END SOON BASED ON LATEST SATELLITE AND RADAR AS DRY SLOT MOVES IN BEHIND FIRST UPPER SYSTEM. THEN LOOKS LIKE MEASURABLE PRECIPITATION WILL HOLD OFF UNTIL THE AFTERNOON WHEN THE NEXT SHORTWAVE AND LEFT FRONT QUADRANT OF JET MOVES THROUGH. LATEST RUC AND GFS LOOK TO HAVE THE BEST HANDLE ON THE ABOVE SCENARIO WITH THE RUC SLIGHTLY BETTER. UP UNTIL MEASURABLE PRECIPITATION STARTS AGAIN...WILL PROBABLY HAVE DRIZZLE AND FOG. WILL HAVE LOWER CHANCE OF PRECIPITATION THIS MORNING THEN INCREASE IT AGAIN. SINCE SNOWFALL HAS PRETTY MUCH ENDED OVER YUMA AND KIT CARSON COUNTY...WILL CANCEL THE WINTER WEATHER ADVISORY FOR THOSE TWO COUNTIES. WITH EXPECTED CONDITIONS...CURRENT MAXES LOOK FINE AND WILL LEAVE ALONE FOR NOW. WILL ADJUST WIND FIELD AND DEWPOINTS WITH THE LATEST RUC. $$ .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ BULLER ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1116 AM EDT FRI APR 30 2004 .UPDATE... UPDATE FOCUS IS WITH PRECIP AND THUNDER POTENTIAL...AS WELL AS TEMPERATURES GIVEN CLOUDS AND WAVERING FRONT. WATER VAPOR LOOP SHOWS ONE SHORTWAVE MOVING THROUGH THE OHIO VALLEY WITH ANOTHER MOVING INTO MISSOURI. SURFACE ANALYSIS SHOWS COLD FRONT DRAPED ACROSS LOWER MICHIGAN FROM NORTHERN ILLINOIS TO EASTERN ONTARIO. REGIONAL RADARS SHOW A LARGE AREA OF RAIN JUST BRUSHING FAR SOUTHEAST MICHIGAN...BUT WEAKER MORE SHOWERY PRECIP ALONG THE FRONT FROM SOUTHWEST TO MID MICHIGAN AND THE THUMB. INITIALLY THE QUESTION WILL BE WITH THE EVOLUTION OF THE FRONT. MSAS ANALYSIS SHOWS LITTLE IN THE WAY OF DISCERNIBLE PRESSURE CHANGES. HOWEVER THE FRONT HAS SHIFTED SOUTHWARD...WITH WINDS AT SAGINAW /MBS/ SWINGING TO THE NORTHEAST BUT WINDS AT SAGINAW /HYX/ STILL OUT OF THE SOUTHWEST. TEMPERATURE AT MBS ALSO DROPPED 5F AS THE WINDS CHANGED BEHIND THE FRONT...ALSO BECAUSE NORTHEAST FLOW IS OFF SAGINAW BAY. HOW FAR SOUTH THIS FRONT MAKES IT WILL BE A BIG HEADACHE. THERE IS LITTLE SYNOPTIC SUPPORT FOR MOVEMENT...WITH FRONT ORIENTATION NEARLY PARALLEL TO THE UPPER FLOW. SOUTHWARD PUSH OVERNIGHT MAY BE MORE INFLUENCED BY REINFORCING COLD AIR WITH NORTHERLY FLOW OVER THE LAKES. SOME HEATING DURING THE DAY ACROSS THE SOUTH /BREAKS SEEN IN VISIBLE SATELLITE IMAGERY SOUTH OF THE FRONT/ MAY WORK TO SLOW THE PROGRESS OF THE FRONT. EVENTUALLY AS THE MISSOURI WAVE LIFTS NORTHEAST...WE SHOULD SEE A WEAK SURFACE WAVE TRACKING THROUGH SOUTHEAST MICHIGAN...WHICH MAY HELP TO LIFT THE FRONT NORTH MOMENTARILY THIS EVENING...BEFORE FINALLY ALLOWING IT TO CLEAR THROUGH BY SATURDAY MORNING. HOWEVER WILL THE FRONT ACROSS THE NORTHERN CWA RIGHT NOW...WILL DROP TEMPERATURES IN THE NORTH. CURRENT GRIDS HAVE HIGHS IN THE LOW/MID 70S IN THE SOUTH. THESE ARE HIGHER THAN GUIDANCE BUT STILL SEEM REASONABLE SOUTH OF THE FRONT...ESPECIALLY CONSIDERING RECENT VISIBLE SATELLITE SHOWING CLOUDS THINNING IN SUBSIDENCE BETWEEN THE FRONT AND THE OHIO VALLEY WAVE. THIS HAS ALLOW TEMPERATURES TO WARM INTO THE UPPER 60S AS OF 15Z. AS FOR PRECIP CHANCES...CURRENT RADAR SUPPORTS CATEGORICAL POPS IN THE NORTH WITH TRAINING LIGHT ECHOES ALONG THE FRONT BUT AT MOST ISOLATED IN THE SOUTH WITH LITTLE LIFT. 12Z ETA STILL DEVELOPS MORE PRECIP ACROSS THE CWA THIS AFTERNOON...WHILE THE 12Z RUC KEEPS IT CONFINED FARTHER NORTH NEAR THE FRONT. GIVEN SOME DESTABIZATION AND APPROACHING WAVE...WILL KEEP SCATTERED POPS GOING IN THE SOUTH. ON THE WHOLE INSTABILITY WILL BE MARGINAL THOUGH...AND WILL ONLY KEEP A MENTION OF CHANCE THUNDER ACROSS THE CWA. && BRAVENDER .PREV DISCUSSION...325 AM EDT FRI APR 30 2004 A CHALLENGING FORECAST WITH QUASI-STATIONARY BOUNDARY JUST TO THE NORTH OF THE CWA (COUNTY WARNING AREA) AND WEAK WAVE APPROACHING FROM THE MID MISSISSIPPI RIVER VALLEY. THE PLACEMENT OF FRONT AND PROPAGATION OF UPPER WAVE WILL HAVE A LARGE IMPACT ON OUR WEATHER FOR TODAY. MEANWHILE, AN AMPLIFIED FLOW ACROSS NOAM (NORTH AMERICA) WITH DIGGING TROF ACROSS CENTRAL CANADA ENTERING INTO THE DAKOTAS WITH CUT-OFF 4-CORNERS LOW. WATER VAPOR LOOP DOES SHOW US AN REGION OF SUBSIDENCE BEHIND THIS WAVE (CURRENTLY OVER MISSOURI AT 06Z) WHICH IS TIMED TO MOVE ACROSS THE STATE AROUND 18Z. A FAIR AMOUNT OF CONVECTION IS IN PROGRESS ACROSS THE DEEP SOUTH EXTENDING INTO OKLAHOMA WHICH IS LIKELY INHIBITING DEEP MOISTURE TRANSPORT BACK INTO THE GREAT LAKES REGION. WITH ALL OF THIS CONVECTION, HARD TO FAVOR ONE MODEL OVER THE OTHER WITH ENSEMBLES LIKELY WASHING OUT THE MAIN FEATURES. BUT ETA/ETA-XX IN THE SHORT TERM WITH THE BLEND OF THE ETA-XX/GFS/UKMET/GEM FOR THE LATER PERIODS. MAIN FOCUS TODAY WILL BE THE PLACEMENT OF THIS QUASI-STATIONARY BOUNDARY. THIS BOUNDARY HAS MADE PROGRESS ACROSS SOUTHERN WISCONSIN WHERE ISALLOBARIC RISES NORTH OF THE BOUNDARY WERE AROUND 3MB/3HR PER MSAS AND LAPS. THIS IS LIKELY DUE TO THE COLD LAKE MICHIGAN WATERS ALLOWING THIS BOUNDARY TO SLIP SOUTH. CLOSER ANALYSIS ACROSS OUR SECTION OF THE STATE REVEALS THIS BOUNDARY JUST NORTH OF THE BAY-MIDLAND BORDER WHICH IS VERIFIED BY THE LATEST LAPS RUN. MODELS DIVERGE QUITE A BIT WITH MOVEMENT AND PLACEMENT OF THIS FEATURE WHICH COULD RESULT IN A HUGE DIFFERENCE FOR HIGH TEMPS AND PRECIP TODAY. AFOREMENTIONED UPSTREAM WAVE WILL APPROACH THIS MORNING ALTHOUGH LOW LEVEL JET PER WIND PROFILERS IS WEAKENING EARLY THIS MORNING...THEREFORE NOT MUCH IN THE WAY OF THE PRECIP RIGHT NOW. BUT WITH SURFACE CONVERGENCE AND SOME DPVA THIS MORNING...THE HIGHER PROBABILITIES WILL BE CLOSE TO THE FRONT WHERE WE WILL HOLD ONTO LIKELY POPS NORTH 1/2 OF THE CWA. FURTHER SOUTH, WE FEEL THAT NOTHING MORE THAN SCATTERED SHOULD DO WELL WHERE THEY ARE FURTHER REMOVED FROM THE FRONT YET SOME INSTABILITY WARRANTED FOR THE SCATTERED POPS. SPEAKING OF WHICH, CAPES REMAIN QUITE LOW ALONG WITH THE REMAINDER OF THE CONVECTIVE PARAMETERS TODAY. TEMPERATURES TODAY, WE WILL ADD ON SOME VALUES ACROSS THE NORTH WHERE THE FRONT IS EXPECTED TO REMAIN JUST NORTH OF THE TRI-CITIES AS SOME BREAKS IN THE CLOUD COVER (MUCH BETTER CHANCE SOUTH CWA) SHOULD AID IN THE PROCESS. THE EXCEPTION MIGHT BE ALONG THE HURON COUNTY COASTLINE WHERE FRONTS OF THIS NATURE HAVE A WAY TO MAKE IT DOWN ACROSS PORT HOPE. AS UPPER TROF ACROSS THE DAKOTAS DIGS SOUTH, RIGHT ENTRANCE REGION OF THE JET INTERACTS WITH THE TIGHT BAROCLINIC BOUNDARY ACROSS THE CENTER OF THE NATION. THIS WILL RESULT IN A DEEPENING WAVE OF SURFACE LOW PRESSURE THAT WILL BRING MORE WIDESPREAD PRECIP TO THE REGION OVERNIGHT. QPF FIELDS SUGGEST QUARTER TO HALF INCH WITH PRECIPITABLE WATERS NEAR AN INCH AND A THIRD. WAVE DEPARTS FOR THE FIRST DAY OF MAY WITH DEEPER MOISTURE AND THETA-E EAST OF THE CWA. THEN, THE ETA-XX/GFS SHOW ANOTHER WAVE DEVELOPING ALONG THE FRONT, DEEPENING AND RACING NORTHEAST ACROSS CLE PLACING US IN A FAVOR POSITION FOR MORE RAIN. THE ETA/UKMET ARE LESS AGGRESSIVE ALONG WITH THE GLOBAL CANADIAN. SINCE THIS CAN NOT BE DISCOUNTED TOTALLY, AS WE HAVE TO WAIT AND SEE HOW 4-CORNERS LOW BECOMES A PLAYER IN THIS DEEPENING TROF, WE WILL HOLD ONTO THE CURRENT THOUGHTS OF LIKELY POPS. STILL LOOKS CHILLY FOR THE LATER HALF OF THE WEEKEND INTO MONDAY WITH STILL THE CHANCE OF SOME SNOW. THANKS TO THE EXTENSIVE COLLABORATION GRR, IWX AND APX! && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ BGM EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1054 AM EDT FRI APR 30 2004 .DISCUSSION... WV IMAGERY SHOWS WSW FLOW ACROSS THE UPR LAKES...WITH A DIGGING TROF INTO THE DAKOTAS AND A CLOSED CIRCULATION OVER THE FOUR CORNERS. WEAK HIGH PRES AT THE SFC HAS SETTLED OVER THE AREA IN THE WAKE OF YESTERDAY'S FROPA...AND RESULTANT LOW LEVEL DRYING HAS PUT AN END TO ANY PCPN. HOWEVER...WITH A MOIST WSW FLOW ALF...CLOUD COVER CONTINUES ACROSS THE AREA...WITH THINNEST AND HIGHEST CLOUD TO THE NORTHWEST. SOME LIGHT SHRA STRETCHING FROM SW WI INTO CENTRAL WI ALONG AXIS OF H8-H7 FRONTOGENESIS AND SOME 300K ISENTROPIC LIFT. RUC SHOWS SOME OF THIS LIFT MOVING INTO THE SRN U P THIS AFTN...AND GRB RADAR DOES INDEED SHOW THIS TREND WITH SOME WEAK ECHOES APPROACHING MENOMINEE CTY. ANY SHRA WILL CERTAINLY BE LIGHT AS WE ATTEMPT TO MOISTEN THE DRY LOW LEVELS...THOUGH WITH THE 12Z GRB SOUNDING JUST TO OUR SOUTH WAS STILL RELATIVELY MOIST FROM SFC-850MB. BELIEVE SOME ISOLD SHRA WORDING SPREADING INTO THE SRN U P IS WARRANTED. BETTER FRONTOGENESIS FROM A SHORTWAVE TO OUR SW SHOULD SPREAD ACROSS THE S AND E THIS EVENING...AND CURRENT FORECAST HAS THIS DEPICTED WELL W/ INCRG CHANCE OF SHRA BY THEN. AN AREA OF LOW PRES JUST E OF LAKE WINNIPEG...ASSOCIATED WITH A NORTHERN BRANCH SHEARING WAVE MOVING INTO WRN ONTARIO...WILL MOVE TO JUST N OF LAKE SUPERIOR BY THIS EVENING. THIS FEATURE SHOULD NOT AFFECT US UNTIL TONIGHT...AND AGAIN WILL MAKE NO CHANGES TO THE DRY FORECAST OUT WEST TODAY. REGARDING TEMPS...THEY HAVE BEEN SLOW TO CLIMB THIS MORNING DUE TO THE LIGHT NLY FLOW AND ABUNDANT CLOUD COVER. THICKER CLOUD WILL PREVAIL THRU THE DAY SOUTH AND EAST OF A NEGAUNEE TO CRYSTAL FALLS LINE...AND IN THIS AREA WILL LOWER EXPECTED HIGHS BY A FEW DEGREES (TO MID/UPR 40S). TEMPS OUT WEST SHOULD NEAR 50F AS THERE WILL BE SOME FILTERED SUN...AND WINDS WILL BE VARIABLE OR A LITTLE SLY AS THE WAVE TO OUR NW APPROACHES. WILL SEND UPDATE SHORTLY TO ACCOUNT FOR SOME TEMP/WX ADJUSTMENTS. JKL REMAINDER OF PREVIOUS DISCUSSION (ISSUED 350 AM)... FOR TNGT...ETA/GFS SHOW SHRTWV TENDING TO SHEAR OUT AS IT ENTERS MORE CONFLUENT SW FLOW/LIFTS NEWD THRU WRN LK SUP TNGT...WITH SFC TROF PASSING THRU FA BUT TENDING TO WEAKEN WITH TIME UNDER THE UPR CONFLUENCE. ALTHOUGH SFC TROF IS STRONGER WHEN IT ENTERS THE WRN ZNS IN THE EVNG...MODELS ADVERTISE MORE QPF OVER THE SE ZNS CLOSER TO DEPARTING FNT/HIER PWAT. IN GENERAL...GFS MORE AGGRESSIVE WITH QPF THAN ETA AND TENDS TO GET MORE SRN BRANCH PHASING...BUT PREFER DRIER ETA AS BOTH MODELS SHOW SHARPER THERMAL GRADIENT/FRONTOGENESIS STAYING SE OF FA WITH LLVL DRY ADVCTN AND WEAK ISENTROPIC DESCENT ON 280K-290K SFCS (H9-7). SINCE ETA ALSO SEEMS TO HAVE A BETTER HANDLE ON THE STRENGTH OF THE NRN BRANCH SHRTWV...ITS SOLN OF MORE OF JUST A NRN BRANCH SYS WOULD SEEM MORE APPROPRIATE. EITHER WAY...GOING FCST LIKELY POPS ACRS THE SE/CHC ELSEHWERE STILL SEEM APPROPRIATE. PCPN TYPE A CONCERN AS WELL...BUT WL GO WITH MAINLY RA AS ETA FCST SDNGS SHOW LLVL AIRMASS BECMG QUITE UNSTABLE THIS AFTN AND DEPTH OF WBLB > 0 A FEW THOUSAND FEET DEEP TNGT...AT LEAST UNTIL SFC TROF PASSES THRU THE WRN ZNS LATE AT TNGT AND COLDER AIR (H100-85 THKNS BLO 1300M) FLOWS INTO FA IN ITS WAKE. GFS FCST H85 TEMPS EVEN HIER THAN ETA...SO WL FCST ONLY RA UNTIL LATE AT NGT OVER THE W WHERE UPSLOPE NW FLOW WL GENERATE SCT -SHRASN EVEN AFTER DEEPER MSTR/ DYNAMICS DEPART. GFS/ETA SHOW MUCH DRIER AIR (PWAT AOB 0.25 INCH) ARRIVING DURING THE DAY ON SAT AS NRN BRANCH TROF PUSHES OVER MN AND SHRTWV CONTINUES SHEARING OUT IN THE SW FLOW AHEAD OF THE MAIN TROF AND A STEADY WNW FLOW IN THE WAKE OF THIS SYS PUSHES COLDER AIR SE AS WELL. WL CARRY SOME MRNG POPS...THEN DRY. ETA FCST SDNGS SHOW CONSIDERABLE LLVL DRYING DURING THE DAY...ESPECIALLY OVER THE DOWNSLOPE SE ZNS...BUT GFS IS MORE STUBBORN TO HANG ON TO THE LLVL MSTR EVEN UNDER THE DRYING ALF. SINCE PREFERRED ETA SHOWS NRN BRANCH SHRTWV DOMINATING OVER THE SRN BRANCH...WL GO WITH MORE OF A DRIER NW FLOW VS THE MOISTER NNW FLOW DEPICTED BY THE GFS (AND NGM) THAT MIGHT BE THE CASE WITH A MORE SRN BRANCH FLAVOR TO THE FCST. CONCERNED ABOUT SOME INSTABILITY -SHRASN OVER THE HIER TERRAIN OF THE NW...BUT ETA FCST SDNGS SHOW SUBSIDENCE INVRN ARND H85 PROHIBITIVELY LO FOR -SHRA... BUT IDEAL FOR SC LINGERING LONGER OVER THE HIER TERRAIN. FCST H85 TEMPS IN THE -4C (SE) TO -7C (NW) RANGE SUPPORT TMAX ARND 50 OVER THE SE TO 40 TO 45 OVER THE HIER TERRAIN OF THE NW. BOTH GFS/ETA IN GOOD AGREEMENT SHOWING CORE OF DRIER AIR REMAINING OVER ALL THE CWA...EXCEPT THE FAR E. SINCE THE GFS IS SLOWER WITH THE PROGRESSION OF THE UPR TROF AXIS WITH MORE PHASING BTWN THE NRN/SRN BRANCHES (ALTHOUGH IT IS TRENDING FASTER AT MOVING THE TROF WITH LESS PHASING)...IT SHOWS SOMEWHAT DEEPER MSTR BLDG BACK INTO THE ERN ZNS AS MORE IMPULSES RIDE NEWD IN THE SW FLOW OF THE UPR TROF AND MAINTAIN MORE CYC FLOW. HAVE OPTED TO REMOVE PCPN FM ALL THE FA SAT NGT-SUN NGT EXCEPT THE ERN ZNS...AS CNDN MODEL A BIT MORE SLUGGISH PUSHING PCPN OUT OF THE FA AS WELL. COORDINATED WITH APX. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BUFFALO NY 1050 AM FRI APR 30 2004 MINOR CHANGES TO THE FIRST PERIOD. CLOUDS A LITTLE SLOWER ARRIVING SO WILL CONTINUE SUNSHINE INTO THE EARLY AFTERNOON BEFORE INCREASING THE CLOUDS. LATEST RUC ACTUALLY HOLDS OFF PRECIPITATION UNTIL TONIGHT. WORKSTATION ETA STILL SHOWS CONVECTIVE PRECIPITATION FORMING ALONG THE LAKE BOUNDARY AND MOVING EAST LATE THIS AFTERNOON. WILL THEREFORE CONTINUE THE CHANCE OF SHOWERS AND THUNDERSTORMS LATE THIS AFTETNOON BUT WILL DROP POP SLIGHTLY. MAX TEMPS TODAY ALSO BUMPED UP A BIT BASED ON CURRENT CONDITIONS AND EXPECTATION OF SUNSHINE LONGER INTO THE DAY. EXTENDED... CURRENTLY WORKING ON TUES THROUGH FRIDAY TIME PERIOD FOR THE MAIN PACKAGE RELEASE THIS AFTERNOON...AND AFTER COLLABORATION WITH BGM... WILL PROBABLY RELY MORE HEAVILY ON CANADIAN GEM AND ECMWF MODELS RATHER THAN THE MRF. AS WAS THE CASE YESTERDAY...THE MRF APPEARS TO BE WAY OUT OF LINE BY EMPHASIZING THE EASTERN TROF. THIS MAKES A 5 TO 10 DEGREE TEMP DIFFERENCE FOR THURSDAY AND POSS FRIDAY MAX TEMPS AS A BROAD SOUTHWEST FLOW IS BEING ADVERTISED BY THE ACCEPTED MODELS. THE DECISION TO FOLLOW THIS SOLUTION ALSO AGREES BETTER WITH BUF (AND BGM) CONTINUITY. MORE TO FOLLOW... AVIATION DISCUSSION... VFR CONDITIONS EXPECTED THROUGH MUCH OF TONIGHT WITH AC CIGS THIS AFTERNOON LOWERING TO 4K FOR TONIGHT. LOW CHC POPS FOR -TSRA LATE TODAY AND THIS EVENING...AND THIS WOULD BE ONLY OPPORTUITY FOR MVFR CIGS. VIS MAY LOWER TO 5SM OR SO LATER TONIGHT WITHIN ANY AREAS THAT PICK UP SOME PCPN BEFORE THAT TIME. SL/RSH ...PREVIOUS DISCUSSION... FOR THE FIRST 24 HOURS OF THE FORECAST...THE ETA INDICATES THAT DIURNALLY-DRIVEN CONVECTION WILL BE THE MAIN FEATURE TO CONCERN OURSELVES WITH...WITH LI'S GOING NEGATIVE AND SOME INSTABILITY (CAPES OF 100-400 J/KG) DEPICTED ON THE BUFKIT PROFILES TODAY. SUFFICIENT MOISTURE WILL ALSO BE IN PLACE WITH SFC DEWPOINTS PROGGED TO CLIMB INTO THE 50S AS THE CONNECTION TO THE GULF IMPROVES...HOWEVER FORCING MECHANISMS FOR PCPN CONTINUE TO BE FEW...AND THOSE THAT DO EXIST ARE RATHER ILL-DEFINED. THERE ARE A COUPLE OF MID-LEVEL SHORTWAVES CROSSING THE AREA DURING THE PERIOD THAT COULD ACT AS A TRIGGER...ONE RATHER WEAK WAVE THIS AFTERNOON...AND ANOTHER SOMEWHAT STRONGER WAVE TONIGHT/EARLY SATURDAY. OF PERHAPS GREATER CONSEQUENCE...THE PREVAILING SYNOPTIC GRADIENT APPEARS JUST WEAK ENOUGH TO ALLOW LAKE BREEZES TO DEVELOP AND PROVIDE BOUNDARIES TO FOCUS ANY DIURNAL CONVECTION THAT FORMS. THIS IS PICKED UP ON RATHER NICELY BY THE ETA12 SURFACE WINDS...WHICH SHOW MESOHIGHS SETTING UP OVER BOTH LAKES THIS AFTERNOON. GIVEN THE RELATIVELY WEAK/MESOSCALE NATURE OF THE FORCING MECHANISMS IN PLACE AND THE MILD LEVELS OF INSTABILITY...HAVE OPTED TO JUST CONTINUE WITH HIGH CHANCE (40) POPS FOR THIS AFTERNOON AND EVENING. EXPECT THE THREAT TO GRADUALLY DIMINISH WITH THE LOSS OF DIURNAL HEATING TONIGHT...THOUGH WILL KEEP AT LEAST LOW CHANCE POPS IN ALL NIGHT OUT OF RESPECT FOR THE 2ND SHORTWAVE CROSSING THE AREA LATER TONIGHT. OUR ATTENTION WILL THEN TURN TO THE FRONTAL SYSTEM CURRENTLY OVER ONTARIO AND THE CENTRAL GREAT LAKES...WHICH IS EXPECTED TO SWEEP A STRONG COLD FRONT ACROSS THE AREA DURING THE COURSE OF THE COMING WEEKEND. BOTH THE ETA/GFS HAVE TRENDED A BIT FASTER WITH THE 00Z RUNS...WITH THE ETA THE FASTEST...BRINGING THE FRONT THROUGH SAT AFT/NITE. GIVEN THE OVERALL INCONSISTENCY OF THE ETA WITH THIS FEATURE THE PAST FEW DAYS...AS WELL AS FACTORS THAT WOULD ARGUE FOR A SLOWER SOLUTION (NAMELY THE STRONG RIDGE OFF THE EAST COAST AND THE FACT THAT THE FRONT IS NEARLY PARALLEL TO THE UPPER FLOW)...FEEL THE SLOWER AND MORE CONSISTENT GFS HAS A BETTER HANDLE ON THINGS. THUS WILL CONTINUE TO SHOW A LATER COLD FROPA...IN LINE WITH CONTINUITY. ALTHOUGH I WILL RETAIN LOW LIKELY POPS FOR SATURDAY NIGHT WITH THE FRONT BISECTING THE AREA...THE BEST THREAT OF RAIN APPEARS TO BE ON SUNDAY...AS A WAVE OF LOW PRESSURE RIDES NORTHEAST ALONG THE SLOW-MOVING FRONT. .BUF...NONE. $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1028 AM EDT FRI APR 30 2004 .UPDATE... ISSUED A MRNG UPDATE TO CHG AFTN POPS. LATEST ETA AND RUC RUNS...AND NOW 12Z NGM MOS...KEEP MUCH OF THE AREA DRY THIS AFTN. MCC OVER OH CRNTLY UNDERGOING IT/S DIURNAL WEAKENING BUT XPCT IT TO STRENGTHEN AS THE AFTN WEARS ON. HWVR...BELIEVE AFFECT AREA WILL BE IN THE XTRM WRN CWA WHERE MESO MODELS SHOW A WEAK INSTABILITY AXIS SO WILL KEEP CHANCE POPS THERE...AND BUST AREA IN THE EAST DOWN BLO THRESHOLD WHERE MODELS SHOW INCRSG STABILITY THIS AFTN. TEMPS SEEM RSNBL...NO ADJUSTMENTS NEEDED. MORFORD PRVS DISC BLO. .DISCUSSION... SATELLITE IMAGERY SHOWS CLEAR TO PARTLY CLOUDY SKIES ACROSS THE FORECAST AREA EARLY THIS MORNING. HOWEVER, PLENTY OF HIGHER LEVEL CLOUDS ARE UPSTREAM, SO I WOULD SUSPECT WE'LL SEE FILTERED SUNSHINE MUCH OF THE DAY. PARTLY SUNNY SEEMS LIKE THE BEST DESCRIPTOR. A SHORT WAVE TROUGH WAS EVIDENT OVER WESTERN TN AS OF THIS WRITING, WITH AN ASSOCIATED AREA OF SHOWERS AND THUNDERSTORMS INTO THE LOWER OHIO VALLEY. OUR SHORT RANGE COMPUTER MODELS ARE CONSISTENT IN TRACKING THIS WAVE NORTHEAST TODAY AND THEN ACROSS NY STATE THIS EVENING. AS THIS SYSTEM GETS CAUGHT UP IN A FASTER, MORE CONFLUENT PATTERN AT OUR LATITUDE, IT SHOULD BEGIN TO SHEAR OUT AND WEAKEN. ALTHOUGH THE MODELS ARE SHOWING THIS TREND, THEY ARE ALSO INDICATING THAT SOME CONVECTIVE ACTIVITY WILL AFFECT MOST OF THE AREA LATER THIS AFTERNOON INTO EARLY TONIGHT. WE'LL CONTINUE WITH THE CURRENT CHANCE OF SHOWERS AND STORMS IN THE FORECAST LATE IN THE DAY AND THIS EVENING. SATURDAY, OUR AREA WILL BASICALLY RESIDE IN BETWEEN SYSTEMS AS THE ABOVE MENTIONED WAVE WEAKENS FURTHER AND ZIPS OFF TO OUR EAST. MEANWHILE, THE MAIN COLD FRONT STAYS WELL BACK TO OUR WEST OVER ONTARIO AND THE WESTERN GREAT LAKES REGION. THE MODELS DO SHOW SOME WEAK, FAST MOVING IMPULSES MOVING UP OVER THE AREA IN THE SOUTHWEST FLOW ALOFT. SINCE DEW POINTS WILL BE INCREASING SATURDAY AFTERNOON AND ADDING TO THE MARGINAL INSTABILITY PRESENT BY THAT TIME, WE DECIDED TO KEEP THE CHANCE OF A SHOWER OR THUNDERSTORM LATER IN THE DAY FOR NOW. EXTENDED (SAT NIGHT - THU)... THE ETA AND GFS SHOW SOME DISAGREEMENTS WITH THE TIMING OF THE NEXT FRONT TO CROSS THE AREA SOMETIME LATE SATURDAY NIGHT THROUGH SUNDAY. THE ETA IS FASTER... PUSHING THE FRONT ACROSS THE AREA EARLY SUNDAY MORNING... WHILE THE GFS DEVELOPS A DEEPER LOW OVER THE EASTERN GREAT LAKES AND DELAYS THE FRONT UNTIL SUNDAY AFTERNOON. AT THIS TIME... PLAYED THE TIMING DOWN THE MIDDLE... EXPECTING A FRONTAL PASSAGE AROUND MIDDAY SUNDAY. BASED ON THIS TIMING... CHC POPS FOR SHOWERS AND THUNDERSTORMS IS WARRANTED SATURDAY NIGHT AND SUNDAY. TEMPS SUNDAY WILL BE HIGHLY DEPENDENT ON THE TIMING OF THE FRONT... AT THIS POINT DECIDED TO COOL HIGHS SEVERAL DEGREES FROM SATURDAY'S HIGHS IN THE WEST... BUT WENT WITH HIGHS ALMOST AS HIGH AS SATURDAY IN THE SOUTHEAST. UNCERTAINTY CONTINUES MONDAY AND TUESDAY. LAST NIGHTS 00Z MRF SHOWED A DEEP STORM SYSTEM MOVING UP THE EAST COAST DURING THAT PERIOD. LATER MODEL RUNS ARE MORE PROGRESSIVE MOVING THE FRONT WELL TO OUR EAST AND DRYING THINGS OUT BY MONDAY. AT THIS TIME WILL GO WITH A CHC OF SHOWERS MONDAY AND TUESDAY... AS LAST NIGHT'S MRF COULD BE CORRECT... AND EVEN IF ITS NOT... THE PASSAGE OF A COLD UPPER TROUGH COULD STILL TRIGGER A FEW SHOWERS. EITHER WAY... TEMPS WILL RETURN TO BELOW NORMAL LEVELS MONDAY AND TUESDAY... WITH HIGHS ONLY IN THE 50S AND LOWS NEAR 40. && .AVIATION... VFR CONDITIONS WILL PREVAIL MUCH OF THE TIME THROUGH EARLY SATURDAY MORNING, WITH MAINLY JUST MID TO UPPER LEVEL CLOUDINESS IN PLACE. HIT AND MISS SHOWERS AND THUNDERSTORMS ARE EXPECTED TO POP UP FROM LATE IN THE DAY INTO THIS EVENING (ROUGHLY 22Z - 04Z). BRIEF MVFR CONDITIONS COULD ACCOMPANY ANY SUCH SHOWERS OR STORMS. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...NONE. PA...NONE. $$ SHORT TERM AND AVIATION...JUREWICZ EXTENDED...MSE ny AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1044 AM EDT FRI APR 30 2004 .UPDATE... WV LOOP SHOWING S/W OVER EASTERN TN AND MOVING NE. BEHIND THE WAVE DRY AIR HAS BUILT OVER CENTRAL TN AND NRN AL AND GA THIS MORNING. RADAR COMPOSITE SHOWING A BROAD BROKEN LINE OF SHOWERS AHEAD OF THE DRY SLOT AND BASED ON TRENDS AND THE MESOETA AND RUC WILL EXPECT THIS ACTIVITY TO CONTINUE EAST OVER THE FA. WILL INCREASE POPS TO LIKELY TO CATE OVER THE MTNS AND LIKELY POPS OVER THE SAVANNAH VALLEY THIS MORNING. BOTH THE MESOETA AND RUC CONTINUE QPF THIS AFTERNOON PARTIAL IN RESPONSE TO H5 VORT MOVING OVER THE WESTERN CAROLINAS. HOWEVER...WITH DRY AIR EXPECTED TO BE IN THE MID LAYER WOULD EXPECT THE COVERAGE TO BE LESS THAN THIS AM...WILL CONTINUE CHC POPS. TEMPERATURES THIS MORNING ARE OFF TO A SLOW START GIVEN THE WIDESPREAD OVERCAST AND PRECIP. LAMP GUIDANCE SUGGEST THAT THIS AFTERNOON'S HIGHS WOULD BE SEVERAL DEGREES LOWER THAN THE CURRENT FORECAST. WILL FOLLOW FLP GUIDANCE FAIRLY CLOSELY IN THE MTNS...BUT WILL GO A CATE HIGHER THAN GUIDANCE EAST OF THE MTNS GIVEN THE CURRENT BREAKS AND EXPECT DRYING ALOFT. TEMPS WILL DETERMINE THE EXTENT OF CONVECTION THIS AFTERNOON. FRESH 12Z MESOETA FORECAST SOUNDING OVER THE UPSTATE AT 21Z SHOWING CAPE BUILDING INTO THE 500-1000 J/KG...THIS LOOKS VERY LIKELY. WILL CONTINUE CHC FOR SHOWERS AND TS WITH FAVOR GIVEN TO THE EASTERN 1/3 OF THE CWA. && .PREV DISCUSSION... REGIONAL 88D LOOPS INDICATE A BROAD AREA OF WEAK CONVECTION UPSTREAM ACRS TENN AND WRN GA ATTM AND 00Z ETA HAS A DECENT ENOUGH HANDLE OF THE SYNOPTIC SCALE FEATURES DRIVING PCPN AS WHOLE. THIS LEADS ME TO BELIEVE THAT MODEL TIME HEIGHTS INDICATING INCREASING DEEPER RH AND OMEGA FROM WEST TO EAST ACRS THE CWFA AS THE DAY WEARS ON BELIEVABLE ENOUGH TO WARRANT CONTINUATION OF GOING POP GRIDS...WITH A WEST TO EAST GRADIENT AND HIGHER VALUES IN THE AFTERNOON. IT CONTINUES TO REMAIN QUITE QUESTIONABLE WITH RESPECT TO AMOUNT OF RH AND LIFT FOR PCPN DURING THE DAYTIME SATURDAY...AS THE CWFA SHOULD STILL BE WELL DOWNSTREAM OF ANY ORGANIZED STRONG CONVECTION OUT AHEAD OF STRONGLY FORCED COLD FRONT DURING THE DAY. EVEN THE EVENTUAL EVOLUTION OF TSTMS...PROBABLY MOVING INTO THE MOUNTAINS SATURDAY NIGHT IS STILL UP IN THE AIR AS STORMS SHOULD BEGIN TO OUTRUN BEST UPPER SUPPORT. TIMING OF COLD FRONTAL PASSAGE SUNDAY STILL ROUGHLY ON TRACK AND AREAS EAST OF THE MOUNTAINS STILL STANDING THE BEST CHANCE FOR ANY STRONG OR SEVERE CONVECTION. 00Z GFS LOOKS TO SLOW UP EASTWARD ADVECTION OF DRY AIR MONDAY...SO WILL CONTINUE TO KEEP POST FRONTAL CHC POPS IN THE FCST THOUGH THE DAYTIME. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ NED sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 950 AM EDT FRI APR 30 2004 .PUBLIC...CURRENT SATELLITE AND RADAR IMAGERY SHOWS MCS ACROSS THE FLORIDA PANHANDLE AND SOUTHERN GEORGIA MOVING EAST. OVER THE EASTERN CAROLINAS...DRY AIR IN THE MID-LEVELS IS KEEPING SKIES PARTLY CLOUDY. THIS IS CREATING DECENT CAP AND LIMITING THE NORTHERN PROGRESSION OF THE MCS. MODIFICATION OF THE CHS SOUNDING SHOWS WEAK INSTABILITY AND THE POTENTIAL TO BREAK THE CAP LATER THIS AFTERNOON DURING THE MAX HEATING OF THE DAY. SO CANNOT RULE OUT A LIGHT SHOWER OR TWO ACROSS THE SC ZONES THIS AFTERNOON. OVERALL TREND AND FORECAST IN THE ZONES LOOKS OK...BUT WILL UPDATE TO REMOVE AFTERNOON WORDING ACROSS THE GA ZONES AND TWEAK POPS UP TO 40 PERCENT ACROSS THE SOUTHERNMOST GA ZONES. && .MARINE...WILL CONTINUE WITH SCA FOR THE OFFSHORE GA WATERS WITH SEAS HANGING AROUND 5 FT. BASED ON THE LATEST RUC...WINDS ARE NOT EXPECTED TO INCREASE MORE THAN 15 KT...SO IT WILL BE BORDERLINE THAT WE WILL HIT ANYTHING HIGHER THAN 6 FT. RUC SHOWS MORE OF AN E OR NE WIND OVER THE SC WATERS WHICH VERIFIES FROM THE LATEST MODEL RUNS. WILL LIKELY INITIALIZE WITH E WIND VEERING TO THE SE BY AFTERNOON. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...SMALL CRAFT ADVISORY AMZ374. SC...NONE. && $$ JR/PY sc SOUTH TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 1015 AM CDT FRI APR 30 2004 .UPDATE...MORNING SOUNDING SHOWS PRETTY STRONG CAP WITH DRY AIR ABOVE THE INVERSION AROUND H8...BUT MESO ETA AND ESP THE RUC BOTH ERODE THE CAP BY LATE AFTERNOON AS TEMPS RISE INTO THE 80S AND POSSIBLY NEAR 90 FAR WEST. THIS MAY ALLOW A FEW TSTMS TO FIRE ACROSS INLAND SECTIONS LATE THIS AFTN AS A VERY WEAK S/WV SEEN IN RUC ANALYSIS MOVES ACROSS S TX. IF ANY STORMS DEVELOP COVERAGE SHOULD BE LIMITED BY LACK OF MOISTURE DEPTH. HOWEVER..ANY STORMS THAT FORM COULD BECOME STRONG...ESP IN THE RIO GRANDE PLAINS GIVEN THE VERY HIGH CAPE VALUES PROGGED IN EXCESS OF 4000 J/KG (BUT THEN AGAIN THE CAP MY NOT BREAK AT ALL TODAY). CURRENT FORECAST SHOWS 20-30 POPS FOR POSSIBLE AFTN CONVECTION. WILL UPDATE TO REMOVE POPS COMPLETELY ALONG THE COAST AS THE MOISTURE CONVERGENCE AND BEST INSTABILITY WILL BE INLAND BY THE TIME ANY ISOLD STORMS MAY FORM AND WILL ADJUST TO SHOW ISOLD POPS ALL INLAND AREAS. .PREVIOUS DISCUSSION... SHORT-TERM (TODAY THRU SATURDAY)...MOIST LLVLS IN PLACE THIS MORNING WITH LOW STRATUS ENVELOPING THE CWA. DEW POINTS IN THE LOWER 70S ACROSS THE REGION. FOR TODAY...A WARM AND HUMID DAY ON TAP AND BREEZY ACROSS SRN COASTAL BEND EXPECT LOW CLOUDS TO BE SLOW BREAKING UP. INSTABILITIES PROGGED TO INCREASE INLAND AREAS OF COASTAL BEND AND RIO GRANDE PLAINS THIS AFTERNOON. WEAK CAP IN PLACE MAY SLOWLY ERODE DURING AFTERNOON. WILL KEEP LOW POPS (20S AND 30S) MAINLY NRN AND INLAND AREAS FOR THIS AFTERNOON. LOW CLOUDS WILL AGAIN DEVELOP OVER THE AREA TONIGHT WITH TEMPS NOT FALLING PAST THE LOWER 70S. UPR LVL LOW OVER 4 CORNERS WILL OPEN UP TONIGHT AND MOVE INTO CNTRL PLAINS AND WEST TX...PHASING INTO NRN STREAM TROF. STILL SOME DIFFERENCES AMONG MODELS WITH EXACTLY HOW FAR SW ENERGY STRETCHES...AND ALSO SOME TIMING DIFFERENCES WITH FRONT. AT ANY RATE...APPEARS RAINFALL IS LIKELY ACROSS SOUTH TEXAS BEGINNING MID-MORNING ACROSS SOME AREAS NORTH AND WEST AND BUILDING EAST. UPR LVL DIVERGENCE LOOKS EXCELLENT ACROSS THE ERN 2/3RDS OF THE AREA BY 18Z WITH 850-500MB OMEGA INCREASING RAPIDLY. PWS PROGGED TO POOL AHEAD OF FRONT AROUND 1.8". INSTABILITY INCREASES MOST AHEAD OF FRONT ACROSS OUR SRN TIER OF COUNTIES. BUT THREAT DURING THE MID-MORNING AND EARLY AFTERNOON HOURS MAY BE LOCALLY HEAVY RAINFALL...AS INITIALLY DIFFLUENT THICKNESS PATTERN SETS UP AND FRONT POSSIBLY SLOWING ACROSS THE WESTERN COUNTIES IMPLY THIS. WILL BE MENTIONING LOCALLY HEAVY RAINFALL ACROSS THE ERN 2/3RD OF THE AREA...ESP GIVEN RECENT RAINFALL AND SAT GROUNDS OVER THE PAST WEEKS. TEMPS TOMORROW WILL BE HIGHLY DEPENDENT UPON FRONT AND RAINFALL. WILL BE FORECASTING GENERALLY UPPER 70S. LONG-TERM (SATURDAY NIGHT THROUGH THURSDAY)...06Z ETA AND 00Z GFS TO A LESSER EXTENT ARE SLOWER WITH MOVING THE MID TO UPPER LEVEL SHORT WAVE TROUGH SATURDAY. WITH THE UPPER TROUGH STILL LAGGING TO THE WEST OVER SOUTHWEST TEXAS AND EXPECTATIONS OF A SLOWER MOVING FRONTAL BOUNDARY THROUGH THE COASTAL BEND...LARGE SCALE ATMOSPHERIC LIFT SHOULD REMAIN OVER THE EASTERN PORTIONS OF THE FORECAST AREA INTO SATURDAY EVENING. WILL CONTINUE THE PRECIP CHANCES INTO THE EVENING HOURS AND THEN DIMINISH TO SLIGHT CHANCE AFTER MIDNIGHT. THE FRONTAL BOUNDARY PUSHES INTO THE COASTAL WATERS SATURDAY NIGHT AND EXPECT WINDS TO BE NEAR SMALL CRAFT ADVISORY LEVELS. THE 00Z MODEL RUNS ARE NOT QUITE AS STRONG WITH THE NORTHERN STREAM UPPER TROUGH AND SOME OF THE SOUTHERN STREAM ENERGY GETS LEFT BEHIND WITH AN UPPER LOW FORMING OVER NORTHWEST MEXICO SUNDAY. EXPECT CLOUDS WILL LINGER OVER SOUTH TEXAS AS A RESULT ON SUNDAY. THE SURFACE HIGH PRESSURE RIDGE WILL REMAIN OVER SOUTH TEXAS INTO MONDAY WITH COOLER TEMPERATURES IN STORE. THE UPPER LOW IS EXPECTED TO REMAIN OVER NORTHWEST MEXICO THROUGH WEDNESDAY WITH THE SURFACE HIGH PRESSURE RIDGE MOVING EAST. A SLOW WARMING TREND IS EXPECTED THROUGH THURSDAY. THE UPPER LOW MAY MOVE SLOWLY EAST BY THURSDAY WITH THE ECMWF SHOWING A MORE ORGANIZED LOW SOUTH OF PHOENIX WITH RETURN FLOW OF LOW LEVEL MOISTURE INCREASING OVER SOUTH TEXAS BY THEN. WILL SEE MORE CLOUD COVER BY THURSDAY. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 83 73 78 59 76 / 05 20 70 50 10 VICTORIA 84 71 77 55 76 / 20 20 70 50 10 LAREDO 91 71 78 57 77 / 20 20 50 50 10 ALICE 87 72 78 57 76 / 20 20 70 50 10 ROCKPORT 83 73 77 61 76 / 05 20 70 50 10 COTULLA 88 70 77 53 76 / 20 20 60 40 10 && .CRP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ MJG...UPDATE 76/JR...SHORT-TERM 89/TMT...LONG-TERM tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 930 AM CDT FRI APR 30 2004 .SHORT TERM...THE 12Z BRO SOUNDING SHOWS A PRETTY UNSTABLE ATMS IN PLACE OVER THE REGION WITH A PRETTY STRONG INVERSION EVIDENT BELOW THE 800 MB LEVEL. PLENTY OF CLD COVER IS IN PLACE OVER THE BRO CWA THIS MORNING AS PLENTY OF LOW LEVEL MOISTURE IS TRAPPED WITHIN THE INVERSION LAYER. THIS WILL BE SLOW TO MIX UP...BUT THE SOUTHEASTERLY FLOW WILL HELP THIS A LITTLE BIT LATER THIS AFTERNOON ALLOWING THE SUNSHINE TO BREAK THROUGH A BIT. HOWEVER...AS THE INVERSION WEAKENS...SOME ISOLD CONV MAY DEVELOP LATER TODAY. WILL UPDATE THE MORNING ZFP TO ADJUST CLD WORDING AND POPS A BIT. OTHERWISE...THE REST OF THE CURRENT ZFP WORDING LOOKS OK FOR THE MOMENT. && .MARINE...AT 7 AM CDT BUOY 020 REPORTED SOUTHEAST WINDS AROUND 10 KNOTS WITH 4-FOOT SEAS. WIDELY SCATTERED SHOWERS WERE OCCURRING OVER THE COASTAL WATERS THIS MORNING...AS JETLET MOVED ACROSS TAMAULIPAS INTO THE GULF. ISOLATED LIGHT SHOWERS WERE ALSO NOTED OVER NORTHERN TAMAULIPAS. WILL ADD SLIGHT CHANCE FOR CONVECTION TODAY. LOCAL SOUNDING THIS MORNING HAS SOUTHERLY FLOW AT AND BELOW 10K FEET...PWAT NEAR 1.3 INCHES...LIFTED INDEX OF -11.3 WITH A STEEP LAPSE RATE ABOVE H9 INVERSION. LATEST WAVE WATCH (GWW) MAINTAINS 3 TO 5 FEET SEAS TDY...5 TO 7 BY SAT PM...AS SE FLOW INCREASES TO 20 TO 25 KTS AHEAD OF AN APPROACHING CF. FROPA TIMING...AND PLACEMENT AND INTENSITY OF THE CONVECTION ASSOCIATED WITH THIS FEATURE ARE IN AGREEMENT BY ETA/GFS NOW. XPCT FROPA NEAR MIDNIGHT SAT...WITH NORTH WNDS AT 25 TO 35 KTS POSSIBLE. SVR TSTM DEVELOPMENT BECMG MORE LIKELY WITH TIME...AND MARINERS SHUD CONTINUE TO MONITOR THE INTENSITY OF THIS WX FEATURE SAT AND SUN. AVN KICKS OUT 40 KTS OF NORTH WND JUST OFF THE CAMERON COUNTY COAST AT 1 AM SUN...WITH GWW BUILDING SEAS TO 8 TO 10 FEET SOON AFTER FROPA. HIGH PRESSURE BUILDS INTO THE REGION SUN PM THRU WED. && .AVIATION...PATCHY IFR CIGS WITH LIFT THIS MORNING...AS 30KT LOW LEVEL JET MIXES DOWN. VFR CONDITIONS BY LATE MRNG WITH BREEZY SOUTHEAST FLOW. LATEST MAV MOS CALLS FOR SLIGHT CHANCE OF CONVECTION THIS AFTERNOON. TONIGHT MVFR CONDITIONS WILL RETURN WITH STRONGER SOUTHEAST FLOW SATURDAY...AS LOW OVER NORTHEAST MEXICO TIGHTENS SURFACE PRESSURE GRADIENT. SCT TO NUMEROUS 1SM +TSRA VRB25G35KTS XPCTD LATE SAT PM THRU EARLY SUN...AS FROPA SHIFTS WNDS NW 15G25KTS BY MIDNIGHT SAT. && .PREVIOUS DISC...(MSAS SURFACE ANALYSIS INDICATED A RELATIVELY STRONG COLD FRONT NOSING ACROSS THE TEXAS PANHANDLE MORNING. CONVECTION CONTINUES TO DEVELOP ALONG THE FRONTAL BOUNDARY DRAPED ACROSS THE SOUTHERN PLAINS AS A 500MB LOW IS MOVING ACROSS THE FOUR CORNERS AREA. WATER VAPOR SATELLITE IMAGES AND RUC 500MB HEIGHT/VORTICITY ANALYSIS INDICATES A COUPLE OF WEAK SHORTWAVES MOVING INTO SOUTHWEST TX AND INTO NORTHEAST MEXICO AHEAD OF THE UPPER LOW OVER THE SOUTHWEST UNITED STATES. THE 00Z GFS MODEL INDICATES SOME CONVECTION DEVELOPING OVER THE WESTERN CWA THIS MORNING WITH SOME 700MB VERTICAL MOTION. THEREFORE...WILL MENTION SOME ISOLATED SHOWERS AND THUNDERSTORMS FOR THE WESTERN ZONES/GRIDS THIS MORNING. HOWEVER...NOT BUYING AFTERNOON CONVECTION WITH THE GFS SO WILL LEAN TOWARDS THE DRIER 00Z ETA. MODELS APPEAR TO AGREE ON TIMING OF THE COLD FRONT MOVING INTO CENTRAL TX TONIGHT WITH STRONG CONVECTION DEVELOPING ACROSS SOUTHWEST TX LATE TONIGHT AS THE 500MB LOW OVER THE FOUR CORNERS REGION MOVES INTO WEST TX AS A TROUGH. WILL INTRODUCE POPS LATE TONIGHT AND INCREASE SATURDAY AFTERNOON AS THE FRONT MOVES INTO SOUTH TX. BEST RAIN CHANCES APPEAR LATE SAT AFTERNOON INTO EVENING AS THE FRONT MOVES INTO DEEP SOUTH TX. GFS STILL PROGGING AN MCS TO DEVELOP SAT NIGHT AS UPPER LEVEL DIFFLUENCE INCREASES. WILL CONTINUE MENTION OF SEVERE WEATHER WITH HEAVY RAINFALL POSSIBLE. RAIN CHANCES SHOULD DIMINISH TOWARDS SUNDAY MORNING AS COLD FRONT MOVES OFFSHORE THE LOWER TX COAST. && .LONG TERM...CLEARING TREND SHOULD CONTINUE AS UPPER TROUGH OVER THE CENTRAL U.S. MOVES EASTWARD. HIGH PRESSURE TO BUILD INTO TEXAS SUNDAY WITH DRIER AND SLIGHTLY COOLER AIR. TEMPERATURES WILL WARM THROUGH THURSDAY AS THE SURFACE RIDGE OVER SOUTH TX MONDAY MOVES EASTWARD ALLOWING RETURN FLOW TO DEVELOP TUESDAY. WITH THE INCREASE IN MOISTURE CLOUDS WILL RETURN LATE TUESDAY.) && .BRO WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPTIC/GRIDS...60 MARINE/AVIATION...59 MESO...ABBOTT THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EUREKA CA 1000 AM PDT FRI APR 30 2004 .DISCUSSION... STRATUS AND FOG SURGING NORTHWARD ALONG THE MENDOCINO COAST THIS MORNING. HAVE UPDATED ZONES 1 AND 2 TO ACCOUNT FOR THIS. FORECAST MODELS NOT REALLY PICKING UP ON THIS FEATURE AS EACH OF THE PRIMARY MODELS INDICATE SURFACE WIND FLOW TO BE GENERALLY SOUTHEASTERLY OR VARIABLE IN AREA OF THE SURGE FOR THE CURRENT TIME. MORNING LAPS MSLP AND SURFACE WIND ANALYSES INDICATE 5 TO 10 KNOTS OF WIND OUT OF THE SOUTH. RUC40 IS THE CLOSEST TO REALITY RIGHT NOW...INDICATING...SOUTHERLY WINDS TO CONTINUE WITH A SHIFT TO WEST-SOUTHWESTERLY ALONG THE MENDOCINO AND REDWOOD COASTS THIS AFTERNOON. 12Z GFS AND MESOETA INDICATE WINDS THIS AFTERNOON SHIFTING TO WEST TO EVEN NORTHWEST ALONG THE COASTLINE FOR THIS AFTERNOON...SQUASHING THE SURGE TO SOUTH OF CAPE MENDOCINO. ALTOGETHER...WHILE THEY ARE NOT DOING WELL SO FAR...BELIEVE THAT THE GENERAL CONSENSUS OF THE MODELS IS THE WAY TO GO. EXPECT THAT...SINCE THE PRIMARY THERMAL MAXIMUM ASSOCIATED WITH THE THERMAL TROUGH HAS SHIFTED INLAND AND THE SURFACE HIGH PRESSURE CENTER OFF OF THE CALIFORNIA COAST IS BUILDING INLAND FROM THE PACIFIC...ONCE HEATING OVER THE INTERIOR GETS GOING THE SYNOPTIC FLOW WILL RESPOND ACCORDINGLY. THUS...SURGE WILL CONTINUE NORTHWARD THIS MORNING...GETTING TO ABOUT CAPE MENDOCINO...BEFORE BEING PUSHED AGAINST THE COAST OR EVEN BACK SOUTH BY A GENERALLY WESTERLY SEA BREEZE THIS AFTERNOON. MORNING PRESSURE GRADIENTS FAIRLY WEAK ACROSS THE REGION...SO THERE SEEMS TO BE NO STRONG PULL FROM THE PRESSURE GRADIENT FORCE TO RESULT IN ANY SORT OF SURGE TO DESTROY A NICE DAY ALONG THE REDWOOD COAST. THUS...REST OF THE FORECAST LOOKS VERY GOOD. && .PREV DISCUSSION... SHARP UPPER RIDGE CONTINUES TO BUILD OVER THE OFFSHORE WATERS ALONG THE WEST COAST. ON THE LARGE SCALE IR IMAGES SHOW RIDGE AXIS EXTENDING NORTHWARD ALONG THE COAST INTO THE GULF OF ALASKA...WITH DEEP LOW ROTATING OVER 150 W AND 43 N. AT THE SURFACE...MSLP PLOTS SHOW LOW PRES CENTER OVER SFO BAY AREA...WITH THERMAL TROUGH PUSHING NORTH ALONG THE OREGON COAST. SAT FOG PRODUCT SHOWS PATCHY STRATUS CLOUD BANK CREEPING NORTHWARD ALONG THE MENDOCINO COAST TONIGHT...WITH CLOUDS AS FAR NORTH AS FT BRAGG AREA AS OF 0830Z. GFS INDICATES LOW WILL REMAIN ALONG THE COAST...PUSHING OFFSHORE NORTH OF CAPE BLANCO BY 12Z FRI. IN COMBINATION WITH NEAR SHORE SOUTHERLY FLOW THIS WILL ALLOW LOW CLOUD BANK TO CONTINUE NORTHWARD PROGRESS THROUGH MIDDAY. THE THERMAL LOW WILL PUSH INLAND THIS AFTERNOON...WITH THE OFFSHORE HIGH BUILDING TOWARD THE COAST. THIS WILL ENHANCE ONSHORE FLOW IN THE AFTERNOON SO THAT WHILE COASTAL TEMPS WILL RISE RAPIDLY AGAIN THIS MORNING...EXPECT WARMING TO BE OFFSET SLIGHTLY BY THE MARINE AIR MASS. IN LIGHT OF THIS HAVE KEPT TODAYS HIGHS SLIGHTLY BELOW THOSE RECEIVED YESTERDAY. HAVE KEPT LOW CLOUD AND PATCHY FOG OVER THE WATERS THROUGH TONIGHT BUT HELD OFF ON PUSHING THE MARINE LAYER INLAND UNTIL SAT NIGHT. AT THIS TIME A WEAK WAVE WILL CROSS THE PACIFIC NORTHWEST AS THE UPPER RIDGE SHIFTS INLAND...WITH A CORRESPONDING INCREASE IN MOISTURE. AS FOR INLAND AREAS...EXPECT HIGHS TO CONTINUE RISING UNDER BUILDING HEIGHTS ALOFT. WARMING WILL CONTINUE THROUGH THE WEEKEND WITH HIGHS IN THE 80S TO NEAR 90. A DOWNWARD TREND IN TEMPS IS EXPECTED STARTING MON UNDER THE INFLUENCE OF A LOW PRESSURE SYSTEM IN THE GULF OF ALASKA. AS FOR THE EXTENDED PORTION OF THE FORECAST...THE PREVIOUSLY MENTIONED LOW CENTER OFFSHORE ALONG 150 W THIS MORNING...WILL DRIFT NORTH TOWARD THE ALEUTIAN ISLANDS THROUGH SUN...THEN MOVE EASTWARD TOWARD THE B.C. COAST BY TUE. MODEL AGREEMENT IS FAIRLY GOOD THROUGH TUE WITH SOME DIFFERENCES BECOMING APPARENT BY WED. HOWEVER ALL SOLUTIONS POINT TO COOLER TEMPERATURES AND INCREASING CHANCES OF PRECIP MON NIGHT INTO TUE AS THE UPPER TROUGH DROPS SOUTH INTO THE PACIFIC NORTHWEST. && .SYNOPSIS... SURFACE HIGH PRESSURE OFFSHORE WILL SLIGHTLY SHIFT ONSHORE TODAY...FORCING THE THERMAL TROUGH TO WEAKEN ALONG THE COAST. THE HIGH WILL SLIGHTLY WEAKEN SATURDAY AS THE TAIL END OF A FEEBLE TROUGH CLIPS THE FAR NORTH COAST. MEANWHILE...AN UPPER LEVEL RIDGE WILL REMAIN OVER AREA THROUGH THE WEEKEND...KEEPING THE INLAND AREAS DRY AND WARM. HOWEVER, A MARINE SURGE FROM THE SOUTH WILL RETURN AREAS OF LOW CLOUDS AND FOG TO THE NORTH COAST THIS WEEKEND. && .EKA WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION: BTL PREVIOUS DISCUSSION: CC/TA ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 245 PM MDT FRI APR 30 2004 .SHORT TERM...TODAY AND TONIGHT...FINALLY WE'VE BEEN GETTING STEADY SNOW PRETTY MUCH ALL DAY WITH SOME HEAVY SNOW AT TIMES BUT BEING LATE APRIL AND THE DAYTIME IT HAS BEEN HARD TO GET IT TO ACCUMULATE MUCH. IN WINTER WOULD HAVE BEEN ABLE TO HOIST ANOTHER ADVISORY. THE DIA CAM DOES APPEAR TO HAVE GOTTEN A GOOD ACCUMULATION BUT MOST PLACES HAVE ONLY HAD SOME ON THE GRASS AND OTHER AREAS NOT EVEN MUCH OF ANYTHING ACCUMULATING ON THE GRASS. TOO BAD THIS DID NOT FALL LAST NIGHT BUT AFTER THAT INITIAL FORCING WITH THE SHORTWAVE LIFTING NORTH THERE WAS A 6 HOUR PLUS GAP BEFORE TODAYS SNOW FILLED IN. THE UPPER LOW APPEARS TO BE SITTING NEAR ALAMOSA WITH THE LATEST RUC AND ETA MOVING IT TO NEAR THE SOUTHEAST CO AND KS BORDER BY BETWEEN 03 TO 06Z. PTL PROFILER CONTINUES TO SHOW DEEP EASTERLY FLOW THROUGH THE TROPOSPHERE AND WITH THE MOVEMENT OF THE UPPER LOW AS FORECAST THE UPSLOPE WILL BE CONTINUING SO THE SNOW WILL BE VERY SLOW TO END. THE MOST INTENSE SNOWS APPEAR TO HAVE SHIFTED MORE TO THE EAST OF DIA BUT THERE IS PLENTY OF DECENT RADAR ECHO EXTENDING NORTH TO THE WYOMING BORDER PUSHING BACK INTO THE FOOTHILLS. THERE IS A LINE OF CLEARING SINKING SOUTH OUT OF WYOMING SO CLEARING WILL OCCUR FROM NORTH TO SOUTH BUT BOTTOM LINE WILL BE TO EXTEND SNOW A FEW MORE HOURS THEN IN THE CURRENT FORECAST. THE WINTER WEATHER ADVISORY WILL BE ALLOWED TO EXPIRE AS FURTHER ACCUMULATIONS FROM TONIGHT ON SHOULD BE RELATIVELY LIGHT...PERHAPS AT MOST 1-3 INCHES IN THE FOOTHILLS TO AN INCH OR TWO ON THE PLAINS BUT STILL ON GRASSY AREAS SINCE EXPECT THE SNOW TO PRETTY MUCH DECREASE QUITE A BIT BY DARK. FOR SATURDAY THINGS SHOULD HAVE CLEARED OUT WITH THE MAIN CONCERN A QUICK MOVING SHORTWAVE DIVING SOUTH IN THE NORTHERLY FLOW THAT WILL BE BRUSHING BY FAR NE COLORADO EARLY IN THE MORNING. A COUPLE OF DAYS AGO THIS LOOKED LIKE IT COULD BRING A DECENT SURGE OF UPSLOPE AND FORCING TO COMBINE FOR QUITE A BIT OF RAIN/SNOW SHOWER ACTIVITY MUCH LIKE LAST SUNDAY MORNING...BUT THE MODELS HAVE TRENDED TOWARDS A WEAKER WAVE FARTHER TO THE EAST WITH GENERALLY LITTLE IF ANY UPPER LEVEL FORCING SO SUCH A SCENARIO SEEMS UNLIKELY AT THIS TIME. WILL PUT A SLIGHT THREAT OF SHOWERS IN THE FAR NE CORNER OTHERWISE NOTHING EXCEPT ISOLATED IN THE MOUNTAINS. SZOKE .LONG TERM DISCUSSION...SHORT RANGE AND MEDIUM RANGE MODELS ARE ALL IN VERY GOOD AGREEMENT IN FORECASTING DRY AND WARM WEATHER ACROSS THE FORECAST AREA THROUGH NEXT FRIDAY. EARLY ON...SOME MID LEVEL MOISTURE WILL LINGER OVER THE MOUNTAINS WHICH COULD RESULT IN A LITTLE CLOUD COVER SATURDAY NIGHT. HOWEVER...WITH HEIGHTS INCREASING FROM THE WEST...NO SHOWER ACTIVITY IS EXPECTED. BY MONDAY...TEMPERATURES AT 700 MB ARE FORECAST TO BE NEAR +10C...WHICH WORKS OUT TO UPPER 70S ON THE PLAINS. THE UPPER RIDGE AXIS IS FORECAST TO MOVE EASTWARD ACROSS THE STATE ON ABOUT WEDNESDAY. BEYOND THAT...LIGHT TO MODERATE SOUTHWESTERLY FLOW WILL KEEP WARM WEATHER IN PLACE THROUGH THE END OF THE WEEK. THE MRF SHOWS A SLIGHT INCREASE IN MID LEVEL MOISTURE FRIDAY AFTERNOON. BUT WILL NOT TAKE ANY ACTION ON THIS SUBTLE CHANGE YET. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. $$ SZOKE/DANKERS co AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CHICAGO IL 424 PM CDT FRI APR 30 2004 .DISCUSSION... DEEP MOIST CONVECTION SOUTH AND WEST OF THE CWA APPEARS AHEAD OF H7 S/WV TROF AXIS PER REGIONAL WV IMAGERY,PROFILER, VWP, FSL RUC-20 AND THE SPC RUC DATA. SFC FRONT IS MOVING SLOWLY SOUTH CURRENTLY DRAPED W-E ACROSS THE SRN HALF OF THE CWA. DEEP MOIST CONVECTION IS EXPECTED TO DEVELOP ALONG AND SOUTH OF THE FRONT PRIMARILY THROUGH SUNSET AS INSTABILITY HAS INCREASED OVER THE PAST FEW HOURS IMMEDIATELY SOUTH OF THE FRONT. VARIOUS CURRENT AND PROGGED KINEMATIC FIELDS AND IN CONJUNCTION WITH THE LOW-LVL THERMO FIELDS INDICATE MINIMAL SMALL HAIL THREAT PERHAPS UP TO 3/4 INCH WOULD BE THE PRIMARY CONCERN WITH ANY STORMS THAT DEVELOP...FORD, IROQUOIS AND LIVINGSTON COUNTIES APPEAR TO REALIZE THE HIGHEST SVR PROBABILITIES THROUGH 23Z THIS AFTERNOON. OVERNIGHT CONVECTION IS EXPECTED TO REMAIN BELOW SVR CRITERIA. AEP/RATZER .AFTERNOON DISCUSSION... COLD FRONT APPEARS TO BE SLOWING DOWN IN SRN WILL COUNTY AND ABOUT READY TO PASS THRU VPZ. COLD LAKE WINDS DROPPED TEMPS SIGNIFICANTLY BUT SOME RECOVERY IN NERN IL/NWRN INDY WITH SOME SUNSHINE PEEKING THRU. NE WINDS TO CONT OVERNIGHT SO THAT LOWS IN LOW TO MID 40S OFF LK MICHIGAN IN NERN IL/FAR NWRN INDY. MAIN FOCUS HOWEVER IS STORMS MOVING NEWD FROM MO AND ENCOUNTERING OUR FNTL BNDRY. THIS ESPECIALLY TROUBLING IN AREAS WHERE SUNSHINE IS PREVALENT. AM THINKING NR 5PM OF STORMS ENTERING SW CWA. PROFILERS AND VAD INDICATING NO SHEAR AND NO LOW LVL JET TO JETTISON MOISTURE OVER BNDRY WELL INTO COLD AIR. EVIDENCE OF PAST PERFORMANCE IN LAST HOUR OR TWO IN MO AND IA SHOWING NO STRENGTHENING YET. IN FACT...IR SATL SHOWS TOPS HAVE WARMED GREATLY. BEST DEVELOPMENT IS IN SERN MO HEADED TO STL AND CGI WHERE TOPS HAVE COOLED. LATEST MCD INDICATING BOWING THERE. SO PROSPECTS FOR SVR FOR SLIGHT RISK AREA SOUTH OF I-80 LOOKING DIMMER. THE S/W ASSOCIATED WITH THIS IMPULSE IS FCST TO MOVE ALONG THE FNT OVERNIGHT AND BE NE OF CWA IN THE MRNG. WRAPARND SHOWERS IN THE MRNG WITH SOME LINGERING TSTM RISK IN SERN CWA SAT MRNG SHUD BE DIMINISHING DURING THE DAY. PCPN ENDING IN THE AFTN NCNTRL IL FIRST THEN SPREADING SE SAT NGT. UPR TROF IS NOT THRU UNTIL SUN NGT. APPEARS TO BE A WEAK WAVE DIVING SEWD FROM THE DAKOTAS TO MID MS VLY SUNDAY. AM LEAVING CHC OF PCPN OUT AT THIS TIME WITH LEANINGS MORE TO GFS THAN ETA. RIDGE BLDG IN MONDAY FOLLOWED BY ANOTHER PASSING COLD FNT ON TUESDAY. LOW LVL WINDS NOT STRONG ENUF TO SUCK UP A LOT OF GULF MSTR WITH THIS WAVE. HOWEVER WILL PUT IN A LOW CHC OF SHOWERS FOR TUESDAY SINCE SOME OMEGA PRESENT ON GFS. ANOTHER RIDGE AND ANOTHER FLOW OFF THE LAKE WEDNESDAY SO AM LOWERING HIGH TEMPS FROM MOS THAT DAY. RLB && .AVIATION... FOR 18Z TAFS...FRONT HAS GONE THRU ALL SITES WITH IFR CIGS NOW TRAPPED BELOW VERY SHALLOW INVERSION AS FRONT BEING OVERRUN BACK INTO WI. SOME SPOTTY DZ N OF FRONT. WAITING FOR HEAVIER RA AREA NOW NE TIP MO TO COME INTO SITES 22-00Z. THIS WILL HOLD IN IFR. PUT TS ONLY IN GYY. WILL BE CLOSE CALL AT MDW BUT MAIN TS SHOULD HOLD JUST TO S. MDW MAY BE BRUSHED. HEAVIEST RA OVER AROUND 06Z WITH 850 TROF PASSAGE BUT -RA TIL LATE MORNING TOMORROW. ONCE HEAVIER RA END SHOULD BE A SLOW LIFT IN CIG/VIS AS DRIER SFC AIR TRIES TO COME DOWN AS NNE WINDS INCREASE LATER TONIGHT. AF && .LOT...WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LK MI...NONE. $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 230 PM CDT FRI APR 30 2004 .DISCUSSION... NEAR TERM CONCERN IS CONVECTIVE COMPLEX MOVING EAST NORTHEAST ACROSS SOUTHEAST MISSOURI. MORNING RUC/ETA MODELS INDICATED DESTABILIZATION AHEAD OF THE COMPLEX THIS AFTERNOON...SUPPORTIVE OF THE CONTINUED SLOW GROWTH OBSERVED ON SATELLITE AND RADAR. MCD 514 FROM THE SPC HAS A GOOD HANDLE ON THIS MCS. LIMITED SHEAR /500 MB WINDS AROUND 30 KTS/ AND EXTENSIVE CLOUD COVER SHOULD LIMIT SEVERE WEATHER POTENTIAL TO JUST ISOLATED HAIL/WIND DMG. HEAVY RAIN POTENTIAL IS ALSO A CONCERN. RECEIVED A REPORT OF .7 INCH IN 30 MINUTES FROM VAN BUREN MISSOURI IN CARTER COUNTY AT 19Z. THE STEADY MOVEMENT OF THIS COMPLEX SHOULD MINIMIZE FLASH FLOOD POTENTIAL...ESPECIALLY GIVEN PAST SEVERAL DAYS OF EXCELLENT DRYING CONDITIONS. SHORT TERM CONCERN FOR TONIGHT IS WHETHER ANOTHER MCS WILL OCCUR OVERNIGHT. A SURFACE COLD FRONT WAS NEAR A LINE FROM KSGF TO KUIN /QUINCY IL/ AT 18Z. THIS FRONT WILL REACH SOUTHEAST MISSOURI WELL AFTER MIDNIGHT. THERE IS A LARGE DIFFERENCE BETWEEN ETA/GFS QPF FOR LATE TONIGHT AND SATURDAY...WITH THE GFS CRANKING OUT MUCH HEAVIER PRECIP. THIS APPEARS DUE TO THE GFS SURFACE WAVE THAT MOVES NORTHEAST ALONG THE FRONT INTO THE LOWER OHIO VALLEY EARLY SATURDAY. CURRENT THINKING IS THAT THE GFS IS TOO STRONG WITH THE LOW AND TOO WET. OUR STORM TOTAL QPF FORECAST GRIDS FOR THIS EVENT WILL TOTAL 1 TO 1.5 INCHES...WHICH IS IN CLOSE AGREEMENT WITH HPC. ISOLATED EXCESSIVE RAINFALL IS POSSIBLE TONIGHT...ESPECIALLY IN SE MISSOURI AND SW ILLINOIS WHERE ONGOING MCS IS SATURATING THE GROUND. IF ANOTHER MCS BECOMES MORE CERTAIN LATE TONIGHT...A FLOOD WATCH WILL NEED TO BE CONSIDERED. SATURDAY APPEARS TO BE A VERY WET DAY AS THE COLD FRONT MOVES SLOWLY SOUTHEAST ACROSS THE OHIO RIVER AROUND 18Z...AND TO KHOP AREA BY 00Z. HIGHEST POTENTIAL OF SURFACE BASED CONVECTION WILL BE SOUTH AND EAST OF PAH...WHERE SOME DIURNAL HEATING WILL OCCUR PRIOR TO FRONTAL PASSAGE. 500 MB WINDS ARE FORECAST TO BE SOMEWHAT STRONGER /NEAR 50 KNOTS PER GFS MODEL/...SO THE POTENTIAL FOR ORGANIZED CONVECTION APPEARS HIGHER ON SATURDAY. THE POST FRONTAL RAINFALL WILL LIKELY LINGER INTO THE EVENING HOURS OVER WESTERN KENTUCKY SAT NIGHT...AND CLEARING WILL BE A SLOW PROCESS. HOWEVER...SUNDAY SHOULD START OUT WITH PLENTY OF SUNSHINE AS DRY NORTHERLY FLOW DEEPENS. A SECONDARY COLD FRONT OR TROUGH WILL MOVE SOUTHEAST ACROSS MISSOURI AND ILLINOIS SUNDAY. THESE SUBTLE SECONDARY TROUGHS ARE SELDOM SHOWN WELL BY THE MODELS. REGARDLESS OF THE SURFACE PATTERN...A WELL DEFINED 700 MB TROUGH /SHOWN BY ETA/ WILL LEAD TO PLENTY OF CLOUDS AND A SMALL CHANCE OF SHOWERS. THE 700 MB TROUGH WILL EXIT THE FORECAST AREA BY 12Z MONDAY. MONDAY THROUGH FRIDAY OF NEXT WEEK APPEARS DRY WITH A WARMING TREND. RELIED MAINLY ON ECMWF FOR THE EXTENDED FORECAST...PER HPC DISCUSSIONS. HOWEVER...THE MORNING GFS SHOWED A WEAK COLD FRONT MOVING SOUTH ACROSS ILLINOIS ON WEDNESDAY. EVEN IF GFS SOLUTION TURNS OUT CORRECT...LIMITED MOISTURE AND INSTABILITY ALONG THE FRONT...COMBINED WITH A LACK OF UPPER SUPPORT...WOULD GREATLY LIMIT PRECIP COVERAGE. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. KY...NONE. MO...NONE. && $$ MY ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 330 PM CDT FRI APR 30 2004 .SHORT TERM...(TONIGHT-MON) LATEST SATELLITE/RUC ANALYSIS SHOWS THE SHORT WAVE THAT GENERATED THIS MORNING'S STORMS IN THE SOUTH...MOVING NORTHEAST ACROSS ALABAMA WHILE THE BULK OF THE TSTMS ARE PROPAGATING TO THE WEST ALONG A MOISTURE AXIS OVER LOUISIANA. THE BLOW-OFF FROM THESE STORMS HAS SENT PLENTY OF CLOUD COVER OVER OUR CWA AND HAVE HELD DOWN TEMPS AND SLOWED THE DESTABILIZATION OF OUR AIRMASS IN ALL BUT THE DELTA REGION. ANY STRONG THUNDERSTORM DEVELOPMENT THIS EVENING SHOULD BE LIMITED TO THAT AREA. A DIFFICULT FCST IS SHAPING UP FOR THE WEEKEND. THE CLOSED UPPER LOW JUST EAST OF THE FOUR CORNERS REGION THIS AFTERNOON WILL CONTINUE TO TRACK IN OUR DIRECTION AS IT OPENS UP AND WEAKENS A BIT...THAT THE MODELS AGREE ON. THE BIG DIFFERENCE IS IN THE EVOLUTION OF THE COLD FRONT AND THE PCPN AMOUNTS ASSOCIATED WITH IT THIS WEEKEND. HAVE CONTINUED FCST TREND AND LEANED TOWARD(OR ALLOWED FOR)THE GFS AND CANADIAN MODEL SOLUTIONS WHICH TRACK SEVERAL WAVES ALONG THE FRONT AS IT MOVES THROUGH OUR REGION. THE FIRST WAVE IS EXPECTED TO MOVE OUT OF CENTRAL TEXAS TONIGHT ALONG THE COLD FRONT CURRENTLY OVER OKLAHOMA AND DRAG THE FRONT INTO THE DELTA BY NOON SATURDAY. THE AIRMASS WILL BE WARM AND VERY MOIST WITH A THETAE AXIS 332-336K AND PWS AOA 1.75IN ALONG WITH SBCAPE AROUND 2000J/KG WHEN THE FRONT MOVES INTO OUR REGION BUT THE BEST DEEP LAYER SHEAR IS EXPECTED TO REMAIN NORTHWEST OF THE REGION. AS THE FRONT MOVES INTO CENTRAL MISSISSIPPI DURING THE AFTERNOON A WAVE IS EXPECTED TO MOVE ALONG THE FRONT AND SLOW THE PROGRESSION OF THE FRONT THROUGH THE REGION AND PROLONG THE TRAINING OF HEAVY RAIN. WIDE SPREAD RAINFALL OF TWO TO FOUR INCHES IS EXPECTED WITH ISOLATED AMOUNTS TO FIVE INCHES ARE POSSIBLE. THE FRONT IS STILL EXPECTED TO BE ACROSS SOUTHEAST MISSISSIPPI AT NOON SUNDAY WHEN GFS TRACKS ANOTHER WAVE ALONG THE FRONT AND GENERATES ANOTHER PRECIPITATION MAX OF OVER 2 INCHES IN THE SOUTH. INSTABILITY SHOULD BE LIMITED AT THIS TIME AND WENT WITH LOWER QPF AMOUNTS. DRIER AIR WILL BEGIN TO WORK INTO THE REGION SUNDAY EVENING. THE UPPER TROUGH WILL REMAIN WEST OF OUR AREA UNTIL LATE MONDAY AND AS HIGH PRESSURE BUILDS OVER THE REGION FROM THE NORTHWEST TEMPERATURES WILL STRUGGLE TO CLIMB OUT OF THE 60S MONDAY. && .LONG TERM...TUE-FRI LOOKS LIKE A DRY PATTERN FOR THE MOST PART THROUGH THE PERIOD. AVN INDICATES A LOW CENTERED OFF THE FLORIDA PANHANDLE SO WILL INCREASE CLOUD COVER FOR TUESDAY OVER THE SOUTHEAST WITH THE INCREASED RH. EXPECT SLIGHTLY COOLER THAN NORMAL TEMPERATURES FOR TUESDAY BECOMING NORMAL BY THE END OF THE WEEK WITH THE INCREASES SOUTHERLY FLOW. && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 22MME/BYRD ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 1208 PM CDT FRI APR 30 2004 .DISCUSSION... SHORT TERM (THIS AFTERNOON - SUNDAY)... THE SCENARIO FOR STRONG TO SEVERE THUNDERSTORMS IS BECOMING MORE INTERESTING TODAY FOR EXTREME SOUTHEAST KANSAS AND THE MISSOURI OZARKS. THE 12Z MESO ETA DOESN'T HAVE A SNIFF WITH THE MAGNITUDE OF INSTABILITY THAT WILL BE PRESENT OVER THE CWA THIS AFTERNOON. THE CONVECTIVE SCHEME IS THE LIKELY CULPRIT FOR THIS AS THE MESO ETA INITIALIZED THIS MORNINGS NORTHERN KANSAS AND MISSOURI STORM COMPLEX ABOUT 200 MILES TOO FAR TO THE SOUTH. THE RUC HAS A BETTER HANDLE ON THE SHORT TERM BRINGING IN AN AXIS OF 1500 TO 2000 J/KG OF ML CAPE INTO SOUTHWEST MISSOURI BY 21Z. WITH THE LOW LEVEL CONVERGENCE AND ASSOCIATED LIFT ALONG THE SAGGING FRONTAL BOUNDARY...STRONG TO SEVERE STORMS WILL BE LIKELY OVER THE REGION THIS AFTERNOON AND TONIGHT. WIND FIELDS ARE EXTREMELY WEAK FOR THE TIME OF YEAR...AND LARGE HAIL AND A POSSIBLE DOWNBURST OR TWO WILL BE POSSIBLE. THE SEVERE WEATHER HAZARDS WILL TRANSITION INTO A FLOOD PROBLEM AS WE HEAD INTO THE OVERNIGHT HOURS. WITH THE SURFACE FRONT GRADUALLY SAGGING ACROSS CENTRAL AND SOUTHERN MISSOURI TONIGHT...SOME LOW LEVEL CONVERGENCE WILL BE PRESENT WITH ALONG THIS FEATURE. THE PRIMARY FORCING MECHANISM HOWEVER APPEARS TO BE INCREDIBLE DIFFLUENCE ALOFT ASSOCIATED WITH A 140 KNOT SPEED MAX AT 250 MB OVER THE CORN BELT. THE RIGHT ENTRANCE REGION OF THE SPEED MAX WILL ASSUME A POSITION OVER MISSOURI TONIGHT WHICH WILL PROMPT ANOTHER ROUND OF HEAVY RAIN TONIGHT AND EARLY SATURDAY MORNING...ESPECIALLY OVER EXTREME SOUTHERN MISSOURI. A FLOOD WATCH IS IN EFFECT FOR AREAS ALONG AND SOUTH OF A COLUMBUS KANSAS TO EMINENCE MISSOURI LINE. DUE TO SATURATED SOILS FROM LAST WEEKS FLOOD EVENT...AND THE FLASHY RUGGED TERRAIN OF THE OZARK MOUNTAINS...I MAY UPGRADE THIS WATCH TO AN AREAL FLOOD WARNING LATER THIS AFTERNOON FOR EXTREME SOUTHERN MISSOURI. LOOK FOR ANOTHER 1 TO 3 INCHES OVERNIGHT ALONG THE BORDER. A DECISION ON THIS WILL BE MADE BY 300 PM. THE STORM COMPLEX SHOULD EXIT SOUTH CENTRAL MISSOURI BY EARLY SATURDAY AFTERNOON WITH A COOLER AIRMASS SPREADING THROUGH. LONG TERM (MONDAY - THURSDAY)... FOR NOW MODELS AGREE ON A DRY AND SEASONAL EXTENDED PERIOD. A PATTER CHANGE WILL OCCUR WITH THE UPPER FLOW OVER THE EASTERN PLAINS AND MISSOURI VALLEY ASSUMING A NORTHWEST FLOW STRUCTURE. THIS WILL BE THE PRIMARY CAUSE FOR THE DRY WEATHER...HOWEVER...UNDER MOST NORTHWEST FLOW CIRCUMSTANCES...THERE USUALLY WILL BE A COUPLE OF DISTURBANCES BRING CLOUDS AND A CHANCE FOR SHOWERS AND THUNDERSTORMS. WAY TO EARLY TO PINPOINT THAT THOUGH SO I'LL KEEP THE FORECAST DRY FROM MONDAY THROUGH THURSDAY. AS THE WEST COAST RIDGE FINALLY BREAKS DOWN TEMPERATURES SHOULD REMAIN IN THE 70S AND LOW 80S TOWARDS THURSDAY. GOOD SOUTHERLY FOR SEVERAL DAYS NEXT WEEK WILL ENHANCE TEMPERATURES AND ALSO HELP TO ADVECT MOISTURE INTO THE NATIONS MID SECTION. THE LOW LEVELS WILL BE JUICED AND WE WILL HAVE TO CLOSELY WATCH MODEL TRENDS FOR ANY UPPER SYSTEMS THAT MAY PROVIDE STORM POTENTIAL TOWARDS NEXT WEEKEND. CRAMER && .AVIATION... COLD FRONT FROM NW MO INTO CENTRAL OK WILL BEGIN MOVING THROUGH AREA AS UPPER LEVEL SHORT WAVE APPROACHES. WILL SEE A BRIEF PERIOD OF VFR CONDITIONS DURING THE AFTERNOON. AS FRONT MOVES THROUGH THE AREA AFTER 00Z...CEILINGS WILL DROP TO MVFR WITH IFR CONDITIONS EXPECTED WHERE PRECIPITATION IS OCCURRING. CONDITIONS ARE EXPECTED TO PERSIST THROUGH 18Z SATURDAY. GAEDE && .SGF WATCHES/WARNINGS/ADVISORIES... .MO...FLOOD WATCH FOR THIS EVENING THROUGH SATURDAY AFTERNOON FOR AREAS SOUTH OF A LINE FROM JOPLIN TO SPRINGFIELD TO EMINENCE. .KS...FLOOD WATCH FOR CHEROKEE COUNTY FOR THIS EVENING THROUGH SATURDAY AFTERNOON. $$ WFO SGF mo AREA FORECAST DISCUSSION...UPDATED FOR MESOSCALE DISC NATIONAL WEATHER SERVICE BUFFALO NY 145 PM FRI APR 30 2004 PLENTY OF HEATING ACROSS THE REGION HAS ALLOWED FOR WEAK LAKE BREEZES...ALONG WITH SOME POPCORN CU WELL AWAY FROM THE LAKES. VIS LOOP SHOWS CU ACROSS THE INTERIOR WRN SOUTHERN TIER...GENESEE VALLEY AND FINGER LAKES REGION WHERE CONVECTIVE TEMPS IN THE MID TO UPPER 70S HAVE BEEN SURPASSED. MEANWHILE LAKE SHADOWING PRESENT WITHIN THE SOUTHWEST FLOW ACROSS BOTH THE IAG FRONTIER AND NORTH COUNTRY... WITH THE MOST NOTICEABLE BEING OFF LK ONTARIO. A LOOP OF 8-BIT PRODUCTS FROM THE KBUF RADAR SHOWS THAT THE LAKE BREEZE RAN JUST EAST OF THE NYSTATE THRUWAY IN CHAUTAUQUA COUNTY TO NEAR BOSTON AND WALES CENTER TO ABOUT VARYSBURG AND ATTICA. DO NOT EXPECT CONVECTION WEST OF THIS LINE FOR THE REST OF THE AFTERNOON... BUT STILL LOW CHC POPS FURTHER EAST. LAPS PRODUCTS SHOW THAT AIRMASS OVER THE GENSEE VALLEY AND FINGER LAKES HAVE DESTABLIZED A BIT OVER THE PAST COUPLE HOURS WITH CAPES RISING TO ABOUT 200 J/KG AND CAP ESSENTIALLY DISAPPEARING. SOME MOISTURE CONVERGENCE IS PRESENT...WITH SFC TD'S HAVING RISEN TO MID 50S SINCE THIS MORNING. LI'S ALSO NEGATIVE IN THIS REGION AS OF 17Z. IF ANY CONVECTION IS GOING TO FIRE THIS AFTERNOON...THIS WOULD BE THE MOST FAVORED AREA. ONLY TRIGGER TO SPEAK OF THOUGH IS THE BEFORE MENTIONED LAKE BREEZE BOUNDARY. AS FOR THE UPSTREAM ACTIVITY OVER WRN LAKE ERIE AND NRN OHIO... THERE IS NO LIGHTNING SHOWING UP THROUGH 1745Z. RUC40 SEEMS TO BE SLOW IN THE ADVANCEMENT OF THIS ACTIVITY BUT LOOKS TO BE HANDLING ITS EAST-WEST PLACEMENT WELL. AFTERNOON PACKAGE AND AFD IN THE WORKS AND WILL BE ISSUED WITHIN THE NEXT HOUR AND A HALF. .BUF...NONE. $$ RSH ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 153 PM EDT FRI APR 30 2004 .SYNOPSIS... SUCCESSIVE SHORTWAVES CONTINUE TO RIPPLE THROUGH THE SOUTHWEST FLOW ALOFT THRU SAT...BRINGING INCREASING LAYER MOISTURE AND SHOWER CHANCES THROUGH SATURDAY...ESPECIALLY ACROSS THE LAURELS AND NORTHWEST MOUNTAINS. UPPER FLOW AMPLIFIES STRONGLY BY LATE SAT AND SUNDAY WITH DEEP TROF DIGGING INTO THE OHIO VALLEY...PUSHING A COLD FRONT THROUGH CENTRAL PENNSYLVANIA DURING THE MORNING AND EARLY AFTERNOON. THIS FRONT WILL SLOW...AND THEN STALL JUST SOUTHEAST OF THE AREA MON FOR COOLER TEMPS AND CONTD CHC OF SHOWERS...WITH HIGH PRESSURE BUILDING IN TUE/WED FOR DRY WX AND MODERATING TEMPS. && .SHORT TERM... INTENSE CONVECTIVE COMPLEX ALONG LOUISIANA GULF COAST HAS ROBBED APPROACHING SHORTWAVE OF DEEPER LAYER MOISTURE...THUS AREAL EXTENT AND INTENSITY OF SHOWER ACTIVITY HAS BEEN WANING ACROSS THE OHIO VALLEY THIS AFTERNOON AS PER REGIONAL RADAR MOSAICS AND SAT PIX. RUC40 ON BOARD WITH THIS TREND...AND AM EXPECTING IT TO CONTINUE THIS EVENING...WITH SFC-4KM SPEED SHEAR LESS THAN 15 KTS AND CAPES BETWEEN 200 AND 450 J/KG2. HIGHEST POPS FOR OUR FORECAST AREA POSTED FOR EXTREME WRN PORTIONS OF CENTRAL PENNSYLVANIA... RANGING TO LOW CHANCE POPS INTO THE CENTRAL MOUNTAINS. MOST OF THE CENTRAL AND EASTERN PORTIONS OF CENTRAL PENNSYLVANIA WILL SEE A DRY EVENING. SHWR ACTIVITY SHOULD DWINDLE FOR THE MOST PART BY LATE EVENING... WITH VARYING AMOUNTS OF CLOUDS OVERNIGHT IN THE DIRTY FLAT UPPER RIDGE WHILE ADDITIONAL WEAK SHORTWAVE TROFS PASS OVERHEAD. FORCING IS QUITE WEAK FOR SHOWER ACTIVITY LATER TONIGHT THROUGH EARLY SATURDAY...BUT CAN'T RULE OUT A STRAY SHOWER DURING THIS TIME PERIOD. MORE LIKELY THAT SCATTERED SHOWERS AND PERHAPS A FEW THUNDERSTORMS WILL DEVELOP IN THE AFTERNOON HEATING SATURDAY AS THE FOREMENTIONED FRONT MOVES EVER CLOSER...FOCUSING DEEPER LAYER MOISTURE AHEAD OF IT. BUT AGAIN...SAT WILL BE MOSTLY A DRY AND WARM DAY - CERTAINLY NOTHING TO CANCEL PLANS OVER. SHARP UPPER TROF MAKES ITS MOVE SOUTHWARD INTO THE UPPER MIDWEST SAT NGT AND SUNDAY...HELPING TO DRIVE BAROCLINIC ZONE AND BEST MOISTURE AND FORCING SOUTHEASTWARD OVER CENTRAL PA SUNDAY. CONSENSUS BLEND OF GFS/ETA INDICATES WETTEST TIME DURING THE MORNING HOURS...WITH DRYING ARRIVING IN THE AFTERNOON FROM NORTHWEST TO SOUTHEAST ACROSS THE FORECAST AREA. SLOWING MOVEMENT OF SYSTEM STILL PROBLEMATIC INTO THE EXTENDED FORECAST...BUT RECENT TRENDS HAVE INDICATED A DRIER SOLUTION FOR LATER IN THE WEEKEND AND EARLY NEXT WEEK...WITH STILL A CHANCE OF SHOWERS SKIRTING SOUTHEAST SECTIONS MON AS WAVES RIPPLE ALONG THE NEARBY BOUNDARY. MAV/MET MOS BLEND USED PRETTY MUCH EXCLUSIVELY THROUGH 36 HOURS. DEVOIR .LONG TERM (MON-FRI+)... DIFFS BTWN THE OPERATION RUNS OF THE GFS DURING THE LAST FEW CYCLES AND THE CANADIAN/ECMWF SOLNS DURING THIS TIME FRAME ARE TROUBLING. BUT...WL FOLLOW HPC MED RANGE FORECASTER AND USE EC FOR FIRST PART OF THE WEEK...THEN LEAN HEAVILY ON THE GFS ENSEMBLE MEAN MASS SOLUTION FOR THE LATER HALF OF THE WEEK. WINTER NOT GIVING UP...AS THE COLD FRONT THAT WL PUSH THRU LATE IN THIS WEEKEND WL BRING IN COOLER THAN NORMAL AIR FOR MON AND PERHAPS TUES...BUT IT SHOULD BE DRYING OUT. SOME INSTABILITY SHRA (WL NOT MENTION SN AT THIS RANGE AND AT THIS TIME OF YEAR - MAY) MAY POP UP IN THE AFTN ON MON AS THE COLDEST POOL OF AIR PASSES OVHD...THUS CHC POPS ESP IN NRN COS FOR MON. SFC HI PRES THEN SETTLES IN FOR TUES BEFORE A FRONT NEARS FROM THE N/NW FOR WED. WENT WITH JUST CHC POPS FOR WED AT THIS POINT...WITH HIGHER NUMS OV THE NRN COS...AS THE POS OF THE SFC HIGH MAY KEEP THIS GUY STARVED FOR MOISTURE (GULF INFLOW LOOKS WEAK/CLOSED). THURSDAY LOOKS DRY AS SFC HI FLOATS IN AGAIN FROM THE NORTHWEST... AND COULD LEAD TO A VERY COLD THURS NIGHT/FRI MORNING! BUT WE SHOULD RECOVER NICELY FRI TO BETTER THAN CLIMO AS WAA STARTS IN EARNEST. GREAT NEWS IS THAT A FLAT/BROAD 5H RIDGE SHOULD BUILD UP OVER THE PLAINS AND MIDWEST LATE IN THE EXTENDED. SO...NEXT WEEKEND (MOTHER/S DAY) THINGS LOOK TO WARM UP (AGAIN) SIGNIFICANTLY TO LEVELS MUCH LIKE TODAY OR WARMER (HOTTER?). DANGELO && && .PRELIMINARY POINT TEMPS/POPS... HARRISBURG 58 77 61 73 / 20 30 30 50 WILLIAMSPORT 58 77 60 68 / 30 30 40 50 BRADFORD 53 71 51 59 / 40 50 70 70 JOHNSTOWN 55 71 55 61 / 30 40 60 50 ALTOONA 56 73 58 65 / 30 40 50 50 STATE COLLEGE 59 75 61 66 / 30 30 50 50 SELINSGROVE 58 77 59 69 / 20 30 40 50 LANCASTER 57 77 60 75 / 20 30 30 50 YORK 58 76 61 73 / 20 30 30 50 && .CTP WATCHES/WARNINGS/ADVISORIES... PA...NONE. && $$ pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 259 PM EDT FRI APR 30 2004 .SHORT TERM... RADAR SHOWING NUMEROUS SMALL SHOWERS HAVE DEVELOPED OVER THE CENTRAL SAVANNAH VALLEY THIS AFTERNOON. RUC DEPICTS A H5 VORT MAX OVER THE AREA OF CONVECTION WITH ANOTHER VORT OVER LOWER AL...BY THIS EVENING RUC QPF AHEAD OF THE VORTS MOVES OVER THE FA. BASED ON RECENT TRENDS SHOWERS ARE MARCHING NORTHWARD...HOWEVER...MSAS LI'S BECOME POSITIVE NORTH OF KGRD. WILL PLACE LIKELY POPS ACROSS NE GA AND THE UPSTATE EXPECTING WEAKENING SHOWERS...FURTHER NORTH WILL COVER WITH CHC POPS. THIS AFTERNOON TEMPS REMAINING CLOSE TO 14Z FLP GUIDANCE AND WILL EXPECT THAT 17Z VALUES WOULD WORK WELL FOR TONIGHT MINS...SUPPORTED BY A BLEND OF MOS VALUES. TOMORROW SHOULD LOOK A LOT LIKE TODAY. WITH AMPLE LOW CLOUDS AND PATCHY FOG IN THE AM...BRIGHT SPOTS IN THE PM. TEMPERATURES WOULD BE SLOW TO RISE IN THE CLOUDY ENVIRONMENT...BUT WITH TEMPS ALOFT WARMING A DEGREE OR SO ON THE MESOETA WOULD PLAN ON SFC TEMPS TO BE SLIGHTLY HIGHER THAN TODAY'S VALUES. PREFERRED ETA FOR TEMPS AND HAVE STUCK CLOSE TO THE MET VALUES FOR MAXES. WITH TEMPS REMAINING ON THE COOL SIDE...INSTABILITY WILL AGAIN BECOME MARGINAL IN THE AFTERNOON. WILL EXPECT SMALL SH AND ISO TS TO DEVELOP AS HARD TO TIME VORTS PASS OVER THE WESTERN CAROLINAS SAT...WITH SLIGHTLY HIGHER POPS GIVEN TO THE AM. SAT NIGHT AND SUN...ATTENTION HAS BEEN GIVEN TO THE TIMING OF THE COLD FRONT ADVANCING AHEAD OF THE FULL-LATITUDE POSITIVE TILT TROF. ETA AND GFS CONTINUE TO REMAIN FAIRLY CLOSE WITH FRONTAL TIMING AS IT ENTERS THE APPALACHIANS ON SUN. LATEST MODEL RUNS ARE TRENDING SLOWER WITH THE FROPA...CROSSING THE TN/NC LINE BY 18Z SUN ON THE ETA AND GFS. MOISTURE CONVERGENCE ALONG THE FRONT REMAINS HEALTHY AND WILL INCREASE POPS INTO THE CATE TO LIKELY RANGE OVER THE MTNS AFTER 6Z SUN. WITH INSTABILITY REMAINING LIMITED SUN WILL KEEP TS CHCS LESS THAN SH...EXCEPT NEAR THE EXPECTED FRONTAL BOUNDARY. ETA AND GFS DIVERGE ON THE SPEED AT WHICH THE FRONT MOVE EAST...WILL FOLLOW THE MORE REALISTIC ETA FOR DETAILS. POPS WIND DOWN FROM WEST TO EAST ON MON. .LONG TERM... WITH SURFACE FRONT PUSHING SE OF AREA BY TUE MORNING...HIGH PRESSURE IS EXPECTED TO BUILD OVER THE SE US. UPPER TROF SLOWLY MOVES OFF COAST BY THU AND RIDGE BUILDS OVER REGION AS WELL...KEEPING CWA DRY THRU NEXT FRI. TEMPS WILL GRADUALLY INCREASE THROUGH THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... GSP 61 74 61 73 / 40 50 60 70 AND 61 74 61 74 / 40 50 60 70 CLT 60 72 61 75 / 30 50 60 70 HKY 60 71 60 70 / 30 50 60 70 AVL 57 71 57 71 / 30 50 70 80 && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ NED/RAB sc