SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO COLORADO 250 PM MDT TUE APR 16 2002 ...MAIN FORECAST CONCERNS CONTINUE TO BE WINDS AND HIGH FIRE DANGER IN SHORT TERM WITH PRECIP CHANCES AND COOLER WX FOR THE WEEKEND... WATER VAPOR AND RUC UPPER AIR DATA HAVE UPPER TROUGH AXIS MOVING OUT OF EASTERN COLORADO...WITH WINDS ON THE DECREASE OVER THE EASTERN PLAINS AND BRISK WEST WINDS CONTINUING ALOFT ACROSS WESTERN COLORADO BEHIND SYSTEM. WINDS WILL CONTINUE TO FALL OFF THROUGH THE EVENING...AND WILL LET THE HIGH WIND WARNING EXPIRE. WATER VAPOR ALSO SHOWING NEXT SYSTEM TO AFFECT THE AREA MOVING ONSHORE OFF THE PAC NW...WITH 120+ KT ULJ ROUNDING THE BASE OF THE LOW INTO THE OREGON COAST ATTM. TONIGHT...WEST FLOW ALOFT BECOMING SOUTHWEST AHEAD OF NEXT SYSTEM MOVING INTO THE GREAT BASIN. NOT MUCH IN THE WAY OF CLOUD COVER... AND WITH DIMISHING WINDS...CURRENT FORECAST TEMPS AND GUIDANCE LOOK GOOD. WED...BROAD UPPER LEVEL SYSTEM MOVES INTO THE GREAT BASIN WITH 120+ KT JET CORE MOVING ACROSS NORTHWEST COLORADO IN THE AFTERNOON. 700MB PROGGED IN THE 25 TO 35 MPH BY 00Z THU WITH 500MB WINDS IN THE 60 KT RANGE ACROSS THE AREA. BUFKIT DATA INDICATING EASTERN PLAINS DRY ADIABATIC UP TO 600 MB...AND AM CONCERNED WITH VERY STRONG WINDS ACROSS THE ENTIRE FORECAST AREA WEDNESDAY AFTERNOON. WILL HOLD OFF ON HIGH WIND WARNING ATTM...BUT WILL HIT HARD IN THE ZONES AND LET THE NEXT SHIFT RE-EVALUATE NEW MODELS. WED NIGHT-FRI..PIECE OF ENERGY MOVES ACROSS THE AREA WED NIGHT/THU... WITH MAIN TROUGH STAYING ACROSS THE GREAT BASIN...KEEPING STRONG SOUTHWEST FLOW ACROSS THE STATE. FRONTAL SURGE MOVES ACROSS THE EASTERN PLAINS LATE THU AFTERNOON...WITH WEAK LOW LEVEL UPSLOPE DEVELOPING ACROSS THE PLAINS FRI. WITH STRONG SOUTHWEST FLOW ALOFT...CWA STAYS IN DOWNSLOPE FLOW WITH NOT MUCH MOISTURE BEING PROGGED WILL KEEP THINGS DRY THROUGH FRIDAY AFTERNOON...WHEN UPPER TROUGH BEGINS TO MOVE INTO FOUR CORNERS. SURGE WILL COOL THINGS DOWN ON FRIDAY...AND WILL KEEP CHANCE POPS GOING IN THE AFTERNOON AS ANOTHER PIECE OF ENERGY ROTATES THROUGH THE FLOW. IN THE EXTENDED (SAT-TUE)...MODELS CONTINUE TO BRING THE TROUGH ACROSS THE STATE SAT AND SUN...WITH DRY ZONAL FLOW SETTING UP FOR MON WITH MRF BRINGING ANOTHER TROUGH ACROSS NORTHERN COLORADO FOR TUESDAY. WILL KEEP CHANCE OF SHOWERS WITH COOL TEMPS THROUGH THE WEEKEND AREA WIDE...WITH DRY AND WARMER CONDITIONS MON AND TUE. .PUB...RED FLAG WARMING FOR FIRE WEATHER ZONES 220>225 (MTNS/SAN LUIS AND UPPER AR RVR VLYS) THROUGH 11 PM. FIRE WEATHER WATCH SAME ZONES FOR WEDNESDAY. MW co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 200 PM EDT TUE APR 16 2002 RUC MODEL HAS 500MB VORT LOGE OVER CENTRAL GA WITH PVA OVER EASTERN PARTS TO SOUTH CAROLINA. NVA PUSHING INTO CWA. MODELS DEPICT THIS WELL & PUSH IT NE & WEAKEN IT. BUILDING RIDGE OVER EASTERN US WELL DEPICTED...& ADDITIONAL SHORTWAVE ENERGY OVER EASTERN TX & SOUTHERN PLAINS PUSHING NE. SOME CI TO SPREAD EAST TO CWA. VISUAL SATELLITE IMAGERY SHOWING MORNING CLOUDS & FOG HAVE DISSIPATED & NOW A GOOD CU FIELD TO SET UP FOR THE AFTERNOON. SEA BREEZE BEGINNING ALONG THE ENTIRE FLORIDA BIG BEND...WITH MOVEMENT INLAND TO REACH AROUND STATE LINES OF AL/FL/GA. NOT EXPECTING EAST COAST FL SEA BREEZE TO MAKE IT TOO FAR WEST & DON'T EXPECT A MERGER OF WEST & EAST. BUT WITH HEATING PAST THE CONVECTION TEMP...SOME INSTABILITY...& LEFT OVER OUTFLOW AREAS FROM YESTERDAY...SEA BREEZE WILL DEVELOP SMALL CHANCE OF AFTERNOON TO EVENING CONVECTION. OTHERWISE...RIDGE PATTERN AT SURFACE & ALOFT WILL HOLD A FEW MORE DAYS. TLH SOUNDING HAD A PRECIP WATER VALUE OF 1.32 INCHES & CONCENTRATED IN THE LOWEST 5K FEET. MODEL TIME HEIGHT CROSS SECTIONS ALSO SHOWING DEPTH OF 70+ MEAN RH IN 700MB LEVEL & BELOW THROUGH FRIDAY OVER AREA. DID SEE AREAS OF LOW CLOUDS & DENSE FOG LAST NIGHT. WILL KEEP IN CURRENT TONIGHT PERIOD. MAV ALSO INDICATING THIS IN ITS RUN. MODEL SOUNDINGS ARE INDICATING A GRADUAL INCREASE IN MOISTURE & INSTABILITY FOR WEDNESDAY & THURSDAY...WITH PRECIP WATER VALUE NEAR AN INCH & A HALF...& AN LI OF AROUND -5.0. THIS TRANSLATES TO POP IN 20-30% RANGE. THEN FRIDAY & SATURDAY...THEY LOWER AS WELL AS MODEL POP...SO WILL GO DRY FOR THESE TWO DAYS. SUNDAY STILL LOOKS OVERALL DRY WITH AVN PRECIP WATER LOWERING TO NEAR 1 INCH & LI OF +3.4. AT THE SURFACE...SURFACE RIDGE PATTERN & UPPER RIDGE APPEAR TO DOMINATE & WILL PULL OUT SMALL POP ON SUNDAY. UPPER RIDGE DOES WEAKEN & RETROGRADE BACK TO SW SOME INTO WEEKEND. MONDAY & TUESDAY AGAIN LOOK LIKE ONLY SMALL CHANCE OF RAIN WITH ONLY SEA BREEZE OR HEATING AFFECTS WILL LACK OF UPPER LEVEL SHORTWAVE ENERGY. THEN NEXT BETTER CHANCE OF RAIN LOOKS LIKE MID-NEXT WEEK WITH FRONTAL BOUNDARY. FIRE WEATHER: RH REMAINS HIGH...NO HIGHLIGHTS. MARINE: WINDS & SEAS WILL REMAIN LOW. NO HEADLINES. PRELIMINARY NUMBERS... TLH 062 087 062 088 2323 PFN 067 081 067 081 2323 DHN 064 086 064 086 2323 ABY 062 085 062 086 2323 VLD 062 087 063 088 2323 .TLH... .AL...NONE. .GA...NONE. .FL...NONE. MCT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 228 PM CDT TUE APR 16 2002 INITIAL CONCERN IS WINDS. 18Z RUC SUGGESTS DROPOFF BY 00Z BUT WINDS SHOULD BE NEAR CRITERIA UNTIL THEN. WILL KEEP ADVISORY GOING THROUGH EVENING AS LAMP SUGGESTS THAT WINDS MAY REMAIN UP A LITTLE LONGER THAN RUC SUGGESTS. ADDITIONAL FORECAST CHALLENGES THIS AFTERNOON REVOLVE AROUND PRECIP CHANCES LATE TONIGHT AND EARLY WEDNESDAY...THEN AGAIN OVER THE WEEKEND INTO NEXT WEEK. ANOTHER CONCERN IS MAX TEMPS FOR THURSDAY. DECENT SHORTWAVE IS PROGGED TO MOVE THROUGH FA OVERNIGHT BY ALL OF 12Z NCEP MODEL SUITE. BIGGEST DIFFERENCES ONCE AGAIN REVOLVE AROUND AVAILABLE MOISTURE. HOWEVER...UNLIKE LAST NIGHTS SHORTWAVE PASSAGE...EVEN DRIER ETA HAS AT LEAST SCATTERED PRECIP OVER THE FA OVERNIGHT. THIS SEEMS REASONABLE GIVEN PCPN ASSOCIATED WITH THE SYSTEM OVER OKLAHOMA. ANY PRECIP FORCED BY SHORTWAVE LATE TONIGHT MAY ALSO BE ENHANCED BY EFFECTS OF DIMINISHING STORMS CROSSING THE MISSISSIPPI FROM THE SPC RISK AREA. WILL GO WITH HIGHEST POPS NW TO ISOLATED SE FOR TONIGHT. DOWNWARD FORCING APPEARS QUITE STRONG BY WEDNESDAY AFTERNOON ALLOWING SKIES TO CLEAR MORE QUICKLY THAN PREVIOUS PACKAGE SUGGESTED. BOUNDARY SHOULD THEN PUSH NORTH LATE WEDNESDAY ALLOWING A RETURN TO TEMPS APPROACHING 90F FOR THURSDAY. TWO-METER TEMPS SUGGEST SOME LOWER 90S POSSIBLY IN WRN FA. WITH SOME UNCERTAINTY ON TIMING OF FRONT EXPECTED TO IMPACT REGION LATE THURSDAY...WILL KEEP TEMPS IN 80S. WILL ALSO NEED TO WATCH FOR POTENTIAL FOR STRONG CONVECTION WITH FRONT. ONCE FRONT MOVES IN ON THURSDAY NIGHT IT SHOULD STALL AS STEERING FLOW REMAINS PARALLEL TO THE BOUNDARY SETTING UP A RELATIVELY WET WEEKEND...PARTICULARLY SRN ZNS. PRELIMINARY CCF FOR COORDINATION PURPOSES ONLY... SPI BB 061/083 062/087 058 10430 PIA BB 060/083 061/087 058 10430 DEC BB 062/082 063/086 060 10330 CMI BB 062/082 063/086 060 10330 MTO BB 063/082 063/086 061 10330 LWV BA 065/081 064/086 061 10230 .ILX...WIND ADVISORY CONTINUES FOR ALL OF CWA THIS EVENING. $$ BARKER il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1055 PM EDT TUE APR 16 2002 MAIN FCST CONCERNS OVERNIGHT ARE SHRA/TSRA POTENTIAL AND TIMING ALONG WITH ANY SEVERE WX THREAT AND HIGH NON-CONVECTIVE WINDS NW. WV IMAGERY AND RUC ANALYSIS INDICATED STRONG SHRTWV FROM WRN SD INTO SRN NEB LIFTING TO THE NORTHEAST. AT THE SFC...991 MB LO WAS LOCATED OVER THE NW CORNER OF MN WITH A COLD FRONT EXTENDING THROUGH WRN MN INTO ERN NEB. COMBINATION OF LOW LVL CONVERGENCE AHEAD OF THE FRONT INTO AIRMASS WITH PLENTIFUL INSTABILITY AND SUPPORT FROM DPVA AHEAD OF THE SHRTWV SUPPORTING STRONG/SVR TSRA FROM CNTRL MN INTO NW IA AND ERN NEB. FARTHER EAST OVER UPR MI...STRONG CAP WITH CINH AOA -150 PER AREA FCST SNDGS AND 00Z KGRB SNDG...HAS PRECLUDED ANY CONVECTION. RADAR AND SATELLITE TRENDS SUGGEST THAT STRONGEST TSRA SHOULD REMAIN TO THE WEST OF UPR MI AS BULK OF SHRTWV ENERGY LIFTS NNE THROUGH NRN MN. IN ADDITION...TSRA WILL ARRIVE (AFT 06Z WEST) DURING DIURNAL MIN AS FCST CAPES OVER WRN UPR MI DROP TO AROUND 500 J/KG. WITH SW UNIDIRECTIONAL SHEAR AND STRONG LOW LVL WIND FIELD (H8 WINDS TO AROUND 50 KTS)...MAY HAVE POTENTIAL FOR ISOLD GUSTY WINDS AT THE SFC TO AROUND 45 MPH. AS FOR TIMING...EXPECT ANY TSRA AFT 06Z WEST AND AFT 09Z INTO CNTRL PORTION OF CWA. KEPT MENTION OVER THE ERN CWA...ALTHOUGH ANY SHRA/TSRA THAT SURVIVE SHOULD ARRIVE CLOSER TO 12Z. EXPECT BEST CHANCE FOR HIGH WINDS OVER THE WEST FOLLOWING FROPA AS WINDS VEER TO THE WEST AND STABILITY DECREASES WITH CAA BTWN 12Z-15Z WED AS MAX ISALLOBARIC GRADIENT MOVES THROUGH. HOWEVER...WINDS MAY BE A BIT TOO SW FOR MAXIMUM IMPACT ON USUAL HIGHER TERRAIN AREAS OF THE KEWEENAW WHERE 260-290 WINDS ARE OPTIMUM. HAVE KEPT ADVY AS SOME GUSTS TO 45 MPH STILL ARE POSSIBLE. .MQT...HIGHT WIND ADVY MIZ001-003 THROUGH WEDNESDAY MORNING. SMALL STREAM FLOOD ADVY MIZ002>005-009>010 THROUGH WEDNESDAY MORNING. JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1100 AM EDT TUE APR 16 2002 12Z RAOBS/WV LOOP AND RUC ANAL SHOW HI AMPLITUDE RDG OVR THE ERN CONUS WITH DEEPENING TROF OVR THE W. AT THE SFC...BIG BERMUDA STYLE HI PRES OVR THE SE CONUS PUMPING WARM SWLY FLOW INTO THE GRT LKS. ENTIRE CWA IN WARM SECTOR E OF 986MB SFC LO IN SD...WITH ATTENDANT WARM FNT TO THE E ON THE NRN FLANK OF SE HI XTNDG ACRS NRN MN INTO WRN LK SUP AND THEN E THRU CNTRL LK SUP. NMRS SHRA/TSRA N OF THIS FNT ACRS ONTARIO...BUT SKIES MCLR ACRS CWA DESPITE SFC DWPTS WELL INTO THE 50S AS 12Z GRB SDNG SHOWING PLENTY OF MID LVL DRY AIR (KINX 20). ANOTHER SHRTWV MOVG N INTO SRN WI...WITH SOME MID LVL MSTR. KDVN SDNG SHOWS KINX OF 27...WITH H5 TEMP DOWN TO -14C (VS -11C AT KGRB). MOST POTENT SHRTWV THIS MVRNG LIFTING NE FM THE SRN ROCKIES AND SUPPORTING SFC LO IN THE NRN PLAINS. MAIN FCST FIRST PD CONCERNS ARE MAX TEMPS AND TSRA CHCS. WITH INCRSG SSWLY FLOW TDAY AHD OF SFC LO MOVG NNE WELL TO THE W... XPCT WARM FNT TO REMAIN N OF CWA. WITH RUC SHOWING H85 FLOW VERY ACYC/DIFFLUENT...XPCT ABUNDANT SUNSHINE TDAY. FCST TRAJECTORIES DRAWING FM MAX TEMPS OBSVD IN THE 85 TO 90 RANGE OVR IA/SRN WI/N MO YDAY...AND XPCT THE HIEST TEMPS TDAY IN THIS RECORD RANGE. BEST CHC TO GET THESE TEMPS ARE IN DOWNSLOPE AREAS ARND IWD/ONT AND MQT. 12Z GRB SDNG INDICATES SSW 40KT WNDS AS LO 2K FT AGL...AND THESE WNDS SHUD BE STRG ENUF TO PREVENT LK BREEZE FM MAKING MUCH PROGRESS INLAND. 06Z ETA INDICATES A SELY LK BREEZE ENVELOPING KEWEENAW PENINSULA TDAY...BUT STRENTH OF SSWLY FLOW WL PROBABLY LIMIT ITS SPRD INLAND TO LESS THAN FCST. AREAS DOWNWND OF LK MI WL SEE SGNFT MODIFICATION OF TEMPS...WITH READINGS REACHING 80 ONLY AT A FEW PLACES WELL INLAND. AS FOR TSRA CHCS...LACK OF LARGE SCALE BNDRY AND ACYC/DIFFLUENT FLOW AT H85 WL GREATLY LIMIT TSRA CHCS DESPITE INCRSG INSTABILITY. MAIN UPR TROF/SFC LO/ASSOCIATED DYNAMICS WL REMAIN WELL W OF CWA...BUT SHRTWV MOVG INTO SRN WI FCST TO LIFT INTO THE ERN ZNS LATER THIS AFTN. THINK POTENTIAL IS THERE FOR ISOLD TSRA TO FIRE ON LIMITING STREAM LINE BNDRY OF LK MI COOLING FM MNM/WRN DELTA/WRN ALGER ZNS...WHERE SHARP SFC TEMP GRADIENT ALREADY IN PLACE (14Z TEMP 73 AT MNM...BUT ONLY 55 AT ESC). MODIFIED 12Z GRB SDNG FOR WORST CASE TEMP/TD 90/59 AND SOME COOLING/MOISTENING ALF ASSOCIATED WITH ARRIVAL OF WI SHRTWV YIELDS CAPE OF 2600 J/KG WITH KINX 27 AND ONLY A -5 J/KG CIN...A NEGATIVE AREA THAT COULD BE BKN BY CNVGC ALG THIS BNDRY. SINCE UPR COOLING/MOISTENING AND SFC CNVGC WL BE LESS OVR THE W WITH LK BREEZE BNDRY LIKELY REMAINING OFFSHORE...WL DOWNPLAY TSRA THREAT THERE AND GO WITH ONLY ISOLD TSRA FOR ZNS BORDERING LK SUP VS GOING SCT COVG. HAVE DROPPED MENTION FOR IRON/DICKINSON WHERE THERE WL BE NO BNDRY TO INITIATE CNVCTN. RUC FCST SDNG FOR IWD INDICATES CNVCTIVE T OF 94 FOR TD OF 62. CALLS FM IRON/CMX COUNTIES INDICATE NMRS SML STREAMS OVR THEIR BANKS...SO WL EXPAND SML STREAM FLOOD ADVY TO INCLUDE THOSE COUNTIES. AFDMQT FM MIDNGT SHIFT FOR LATER PDS: A SVR BOW ECHO SHOULD BE ONGOING THIS EVENING IN ADVANCE OF THE FRONT TO THE WEST OF THE FA AS STRONG SLY FLOW WILL HELP TO ADVECT HIGH MOISTURE AIR INTO DLH/S CWFA...WITH VERY STRONG UNIDIRECTIONAL FLOW IN THE LOWER LVLS. LOOKS LIKE THE FRONT WILL REACH THE FA BTWN 6-12Z WHERE INSTABILITY WILL BE MUCH LESS DUE TO LOSS OF DAY TIME HEATING. HOWEVER...WITH LOW LEVEL SHEAR PROFILE BEING SO STRONG (AROUND 40-45KT THIS EVENING)...FEEL TSTMS COULD CONTINUE OVER THE FA TONIGHT. BEST CHC FOR ANY SVR WILL BE FAR WEST WHERE THEY WILL HAVE THE BEST INSTABILITY...BUT THIS EVEN SEEMS MINIMAL WITH MODELS SHOWING MOISTURE VERY LIMITED WITH LACK OF SIGNIFICANT ISENTROPIC LIFT. ALSO...TSTMS WILL BE WEAKENING AS THEY MOVE ACROSS THE FA AS THE FRONT BECOMES MORE DISPLACED FROM THE UPR LVL ENERGY. ONE FAVORABLE FACTOR IS THAT THE AREA WILL BE UNDER THE NOSE OF A 45-55 KT LLJ WHICH SHOULD MAXIMIZE ANY MOISTURE FLUX CVRG. NONETHELESS...AM NOT TOO EXCITED ABOUT SIGNIFICANT PCPN TONIGHT AS BEST VORT ENERGY RIDES WELL TO THE NORTH OF THE FA...WITH LITTLE OR NO JET DYNAMICS OVER THE FA TO SPEAK OF. PRETTY STRONG CAA AND DOWNWARD MOTION BEHIND THE FRONT WILL LEAD TO SOME BREEZY TO WINDY CONDITIONS ON WED. BEST WINDS WILL BE DURING THE AFTN WHERE DAYTIME HEATING WILL CAUSE DESTABILIZATION AND MIXING TO OCCUR. BUFKIT SUGGESTS 30-40KT GUSTS DURING THE AFTN AS H8 TEMPS LOWER TO 1-4C BY AFTN. STRONG WLY ISALLOBARIC COMPONENT NOTED ACROSS THE FA THROUGH 18Z...WITH IT BEING MAXIMIZED OVER THE KEWEENAW. INTERESTING TO NOTE THE SECONDARY VORT MAX THAT MOVES RIGHT OVER THE W AND NW UP AROUND 18Z. WILL NEED TO WATCH THE KEWEENAW FOR POSSIBLE ADVY TMRW. ONLY OTHER CHANGE WILL BE TO SPEED UP THE TIMING OF THE NEXT SYSTEM ON THU. ALL MODELS SHOW RAIN ENCOMPASSING THE ENTIRE FA BY 18Z. .MQT...SMALL STREAM FLOOD ADVY MIZ002-003-009-010 THROUGH THIS EVENING. KC mi AREA FORECAST DISCUSSION FOR CENTRAL/N-EAST SD AND W-CENTRAL MN...UPDATED NATIONAL WEATHER SERVICE ABERDEEN SD 1002 AM CDT TUE APR 16 2002 UPDATE NEEDED THIS MORNING TO BUMP UP THE WIND A COUPLE CATEGORIES IN ALL ZONE GROUPINGS. WENT WINDY BUT NOT ADVISORY. IN ADDITION...RUC AND REAL-TIME DATA SUGGESTS POSSIBLE RECORD HIGH TEMPS IN THE EAST CWA AND 13Z SPC DAY ONE CONVECTIVE OUTLOOK CONTINUES TO SHOW EAST CWA IN HIGH RISK FOR SEVERE POTENTIAL. WILL BE UPDATING HWO LATER THIS MORNING. REMOVED ALL POPS AND PRECIP MENTION IN THE WESTERN CWA AS PER DRIER LOW LEVELS AND WINDS FROM THE NORTHWEST ALREADY. THINKING WAS TO REDUCE CENTRAL CWA POPS AS PER FROPA/LOW CENTER PASSAGE TIMING TO BE JUST AT OR BEFORE MAX HEATING/TIMING OF MOST FAVORABLE MID/UPPER LEVEL DYNAMICS. .ABR...NONE. DORN/MOHR sd SOUTHEAST TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 955 CDT TUE APR 16 2002 UPPER LEVEL ENERGY MOVING RAPIDLY NORTHEASTWARD ACROSS CWFA THIS MORNING. SURROUNDING SOUNDINGS CONTINUE TO INDICATE CAPPING NEAR 800 MB AND RUC IS HINTING THIS WILL HOLD. HOWEVER...ETA INDICATE NO CAP AT ALL BY 18Z. INDICATIONS FROM MOSAIC RADAR LOOPS SHOWS CAP HOLDING ON WITH ONLY WEAK CONVECTION MAINLY WESTERN ZONES. THIS SHOULD SPREAD E AND NE ACROSS CWFA BY MID DAY BUT STAYING WEAK IF CLOUD COVER REMAINS WIDESPREAD. PREVIOUS REASONING AND FORECAST PACKAGE FOR THE MOST PART ON TRACK. WILL MAKE ONLY MINOR 1ST PERIOD ADJUSTMENTS. SURFACE WINDS GUSTING TO 20 KTS IN MANY AREAS DESPITE CONSIDERABLE CLOUD COVER. .HGX....NONE. CLL CB 083/069 086/067 3-0 IAH CB 082/069 086/068 3-0 GLS CB 079/071 079/071 2-0 37/46/DH -------------------------------------------------------------------- PREVIOUS DISCUSSION... WATER VAPOR DEPICTS A VIGOROUS UPPER CIRCULATION MOVING INTO NORTH CENTRAL MEXICO AND AN IMPRESSIVE PLUME OF MOISTURE ASSOCIATED TO THE EAST OF IT. CONVECTION MOVED OFF THE HIGH TERRAIN AND INTO TEXAS NEAR UVALDE BRINGING WITH IT SOME VERY IMPRESSIVE CG LIGHTNING RATES. LOW LEVEL FOCUS IS VERY HARD TO FIND BUT THE AREA IT IS MOVING INTO IS MUCH MORE MOIST BUT SHOULD BE MORE CAPPED AND WAS THE DOWNSTREAM FROM THE WARMER READINGS OF YDAY AFTERNOON. ETA/AVN BOTH ERODE THE CAP THIS MORNING OVER THE FA AS THIS SYSTEM APPROACHES...IN TURN DEPICTING UNCAPPED SOUNDINGS WITH LI -2 TO -5...CAPE OF 1500-2500... AND WEAK LL SHEAR. RUC THROUGH 18Z HOLDS ON TO THE CAP. AVN DIDN'T INITIALIZE THE WIND FIELD AT 250 MB VERY WELL OVER MEXICO AND WESTERN TEXAS...SO AM HESITANT TO BITE ON IT. IF NOT FOR THE STRENGTH OF THE CONVECTION ALREADY ONGOING I WOULD BE INCLINED TO LEAVE POPS AT 20 AND MENTION SHOWERS BUT...WILL CONTINUE TO MENTION THUNDERSTORMS AND WILL PROBABLY CARRY 30 POPS MOST AREAS ALONG AND NORTH OF I-10. WILL CARRY SHOWERS IN THE CWF FOR THE BAYS AND NONE OFFSHORE. NO MENTION OF SEVERE...WILL LET THE 12Z SOUNDING FROM CRP INDICATE IF IT IS WARRANTED. AFTER THIS SYSTEM SWEEPS THROUGH (BY 21Z) THE AREA STABILIZES AND PATTERN RETURNS TO ONE OF QUIET. UPPER RIDGE OVER THE GULF BUILDS TO THE WEST INTO EASTERN MEXICO RESULTING IN SW FLOW ALOFT AND THE WEATHER SYSTEMS ALL WELL TO THE NORTH THROUGH FRIDAY NIGHT. SLOW MOVING COLD FRONT SHOULD BE DRAPED ACROSS NORTH TEXAS SATURDAY AND IN THEORY WASHED OUT BY MONDAY NIGHT...WILL LIKELY WARRANT THE MENTION OF PRECIP HERE ON SUNDAY AND MONDAY. --------------------------------------------------------------------- tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHEYENNE WY 154 PM MDT TUE APR 16 2002 SHORTWAVE TROUGH WAS MOVING INTO EASTERN WYOMING AND CENTRAL COLORADO AT MIDDAY WITH THE MOST ENERGETIC PORTION IN SOUTH CENTRAL COLORADO. CLOUD BAND HAS BEEN ENHANCING SINCE MID MORNING AHEAD OF THE FEATURE WITH SOME LIGHT SHOWERS ALONG THE WYOMING AND NEBRASKA BORDER AS WELL AS OVER THE MOUNTAINS. MODELS INCLUDING THE 17Z RUC INDICATE THAT THE SHORTWAVE TROUGH WILL BE OVER THE PANHANDLE AT 00Z. WILL KEEP A MENTION OF SHOWERS OVER THE PANHANDLE IN THE EARLY EVENING HOURS BEFORE THE SHORTWAVE TROUGH EXITS. ATTENTION THEN TURNS TO THE STORM SYSTEM THAT WILL DEVELOP THURSDAY AND FRIDAY OVER THE GREAT BASIN BY THURSDAY AND THEN MOVE ONLY SLOWLY EAST THROUGH FRIDAY. THE SOUTHWEST FLOW ALOFT AHEAD OF THAT SYSTEM WILL PRODUCE STRONG SOUTH OR SOUTHWEST SURFACE WINDS AND WARMER TEMPERATURES ON WEDNESDAY. CLOUDS WILL SPREAD OVER THE CWA FROM WEST TO EAST LATE TONIGHT THROUGH WEDNESDAY AFTERNOON IN THAT FLOW. SOME SHOWERS WILL ALSO FORM IN THE AFTERNOON IN THE SOUTH CENTRAL PART OF WYOMING IN THE DEEPER MOISTURE. MODELS SEEM FAIRLY CLOSE FOR THIS FORECAST WITH THE MAIN DIFFERENCE BEING THE UPPER LOW THE AVN DEVELOPS BY 12Z THURSDAY IN EXTREME NORTHWEST SOUTH DAKOTA. THIS SEEMS OVERDONE AND NOT AT ALL CONSISTENT WITH ITS PREVIOUS RUN. FOR THAT REASON HAVE WENT MORE WITH THE ETA. THE ETA ON THURSDAY AND FRIDAY HAS A BIT LOWER HEIGHTS ALOFT AND THICKNESS VALUES THAN THE AVN. IT IS ALSO SLIGHTLY SLOWER IN MOVING THE PRECIPIATION OVER THE CWA THAN THE AVN...HOWEVER IT IS TRENDING FASTER THAN ITS 00Z RUN. FOR LATE WEDNESDAY NIGHT THROUGH FRIDAY THE UPPER LOW IS IN THE GREAT BASIN...WITH THE 300 MB JET FROM SOUTHWEST TO NORTHEAST WYOMING. THE 300 MB JET SAGS VERY SLOWLY SOUTH DURING THAT TIME...WITH MOST OF THE PRECIPITATION ON THE CYCLONIC SIDE OF THAT JET. IN ADDITION...SEVERAL SHORTWAVE TROUGHS MOVE OVER THE AREA ALONG THE JET. THE INITIAL ASSOCIATED SURFACE LOW MOVES ONTO THE NORTHERN PLAINS WEDNESDAY NIGHT AND THURSDAY MORNING AND MOVES A PACIFIC COLD FRONT THROUGH THE CWA LATE WEDNESDAY AFTERNOON AND EARLY THURSDAY NIGHT. AT THE SURFACE...MOST OF THE PRECIPITATION IS BEHIND THE CANADIAN POLAR FRONT WHICH MOVES THROUGH FROM NORTH TO SOUTH THURSDAY AFTERNOON AND EARLY THURSDAY NIGHT. CYCLOGENESIS TAKES PLACE OVER SOUTHWEST COLORADO ON FRIDAY...ENHANCING THE SURFACE UPSLOPE WIND FLOW OVER ESPECIALLY THE SOUTHERN PART OF THE CWA. WITH THE COLD AIR IN PLACE THERE WILL BE ACCUMULATIONS THURSDAY NIGHT AND FRIDAY. .EXTENDED... UPPER TROF FCTS TO CONT HANGING AROUND OVER THE WRN U.S. THRU THE WEEKEND WHILE GRDLY FILLING. SHOULD BE AREAS OF LIGHT SNOW OVER THE CWA SAT WITH UPSLOPE FLOW...WITH PCPN DCRG LT SAT WITH UPSLOPE WKNG. OVERALL TROFFING CONTS OVER THE WRN CONUS INTO NEXT WEEK WITH SW FLOW OVR AREA...SO SOME LOW CHCS FOR PCPN SHLD CONT IN ASCTN WITH ANY WK WVS EJECTING NE OVR AREA FM TROF. TEMPS QUITE COOL SAT WITH SLOW MODERATION SUN-TUES. AGAIN WILL FAVOR COOLER MEX NUMBERS AS FMR LOOKS TO PUT TOO MUCH WEIGHT ON CLIMO. .CYS... WY...NONE. NE...NONE. WEILAND/EMANUEL wy AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 400 AM CDT WED APR 17 2002 CDFNT CURRENTLY EXTDG FM WRN WI SW THRU NWRN MO TO WK SFC LOW OVR N CNTRL OK. WDLY SCT SHRA AND TSRA CONT TO DVLP OVR NRN MO W CNTRL IL ALNG AND JUST AHD OF CDFNT AND THIS SHOULD CONT AS LATEST MSAS DATA SHOWING SFC MOISTURE CNVG MAXIMIZED OVR NWRN MO WITH SFC LI VALUES OF -4 OVR MUCH OF MO SE OF CDFNT. SEWD PUSH OF CDFNT SHOULD SLOW AS LATEST 3 HR PRES RISES BHND CDFNT HAVE WEAKENED AND WERE CNTRD FURTHER N IN MN. CDFNT SHOULD BCM E-W ORIENTED ACRS NRN MO TDA THEN SHIFT NWD AS A WRMFNT THIS EVNG. EXCEPT FOR THIS WK LOW LVL BNDRY DO NOT SEE MUCH FRCNG FOR CONVECTION TDA WITH WK SHRTWV PUSHING E OF CWA...AND MCV OVR SWRN AR REMAINING S OF FCST AREA. LATEST RUC ANALYSIS INDICATING BEST 850 MB THETA E ADVECTION...MOISTURE CNVG AND WAA ON NOSE OF 35-40 KT SWLY LLJ HAVE PUSHED NE OF CWA THIS MRNG. WILL CONT LOW POPS OVR CNTRL MO TDA BUT BEST POTENTIAL FOR PCPN SHOULD REMAIN OVR UIN AREA TDA INTO THIS EVNG THEN SHIFT WELL N OF AREA LTR TGT AS STRENGTHENING WRMFNT LIFTS NWD AS SFC LOW PUSHES NEWD THRU THE NRN PLAINS. WL CONT TO GO ABV NGM AND AVN MOS GUIDANCE TEMPS FOR MAX TEMPS TDA AND THU WITH THE WRMR ETA 2 M TEMPS APPEARING THE MOST REASONABLE. WK SHORT LIVED LOW LVL CAA THIS MRNG OVR THE UIN AREA AND PATCHY SC OR SCT CU SHOULD KEEP TEMPS FM GETTING QUITE AS WRM AS YESTERDAY OVR THE NRN PTN OF THE CWA. MOST OF THE MID-HI LVL CLOUDINESS SHOULD SHIFT E OF CWA BY AFTN...ALTHOUGH MDLS DEPICT RELATIVELY HI BNDRY LYR RH TDA AND SHOULD SEE THE DEVELOPMENT OF SCT CU AT LEAST ALNG AND N OF WK FNT ACRS NRN MO. WARMEST TEMPS EXPECTED ON THU AS ETA MDL FCSTS 18-20 DGR 850 TEMPS ADVCTG NEWD INTO CWA. STG CDFNT MOVD SEWD INTO REGION THU NGT INTO FRI SHOULD BRNG THE BEST CHANCE OF RAIN AND MORE SEASONABLE TEMPS TO THE AREA. .STL...NONE GKS mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 330 AM CDT WED APR 17 2002 FORECAST CHALLENGES...RETURN OF SFC FNT AND DVLPMENT OF TSRA THIS AFTERNOON AND TONIGHT. SYNOPSIS...AFTER AN ACTIVE SVR WX NIGHT FOR THE FCST AREA...NEGATIVELY TILTED TROF SWEEPS NORTHEAST...SHIFTING THE TSRA TO MN-IA-ERN KS. SFC FNT PUSHING THRU SW IA NOW AND DEWPOINTS HAVE FALLEN TO THE 30S/40S BEHIND THE FNT AND THE WNDS HAVE DIMINISHED SIGNIFICANTLY. FORECAST...ERLY THIS AM MINOR SHORTWAVE FCST BY ETA TO PRODUCE PRECIP...HOWEVER SHORT TERM AVN/RUC DRY. STLT INDICATING STG DRYING AND SUBSIDENCE AND WILL KEEP VERY SHORT TERM FCST DRY. MAIN UPR LOW OVR WA CONSISTENTLY FCST BY BOTH THE ETA/AVN TO WEAKEN AND SPLIT INTO TWO LOWS NR OR AND MT BY 06Z TONIGHT. SHORT TERM FCST INVOLVES SFC FNT KS/MO THAT PUSHES N INTO SE NEB/SRN IA LATE TAF. MODELS DIFFER ON THE LOCATION OF THE SFC LO AT 00Z WITH THE ETA/AVN SIMILAR OVR ERN WY AND THE NGM FARTHER N OVR ERN MT. NGM CONTINUES NWD BIAS AT 12Z AS ETA/AVN HAS THE SFC LO OVR ERN SD AND SFC FNT INTO ERN NEB. MID DAY THU THE FNT EXITS THE FCST AREA AND SFC HI PRES BUILDS IN FM MT. HI PRES RMNS OVR THE FCST AREA WELL INTO THE EXTENDED. DAYS 1 AND 2...MODEL TRENDS CONTINUE TO WEAKEN SHORT WAVE TROF AND ETA SEEMS TO HANDLE THIS BEST. DAY1 SPC OUTLOOK HAS ERN NEB AND WRN IA IN SLGHT RISK FOR DAY 1 VALID THRU 12Z 4/18. WAA/INSTABILITY/FAVORABLE SHEAR PROFILES DEVELOP LATE THIS AFT AND INCREASES THIS EVE. CAPE VALUES INCREASE TO 1-2K J/KG ACRS SE NEB TAF AND 2-3K J/KG THIS EVE. HAVE INCLUDED CHC FOR TSRA LATE TAF SE AND ALL OF THE FCST AREA TON AND LEFT THU DRY. TEMPERATURES TAF MID 70S N TO LOWER 80S S. S/SE WINDS TO INCREASE LATE THIS AFT AND EVE INTO THE BREEZY CATEGORY. DURING THE DAY THE SFC BOUNDARY PUSHES ACRS THE FCST AREA. FOR NOW HAVE MAINLY GONE DRY FOR THE REST OF THU/FRI AS THE SFC BOUNDARY/MID LEVEL WAA AFFECTS LOCATIONS FARTHER S. EXTENDED...SAT-TUES. SFC HI PRES AND NE FLO IS FCST FOR THE AREA SAT AND SUN. THERE ARE SOME TIMING DIFFERENCES WITH THE NEW MRF. THE OLD MRF HAD 30/40 POPS FOR SEVERAL DAYS. THE NEW MRF STILL HAS 30/40 POPS...HOWEVER...HAS THE GREATEST CHC PRECP SUN AND WED. IF YOU HAVE COMMENTS ON THE NEW FORECAST DISCUSSION FORMAT...PLEASE E-MAIL THEM TO W-OAX.WEBMASTER@NOAA.GOV OR CALL DAVE THEOPHILUS AT 402 359-5166. .OMA...NONE. ZAPOTOCNY ne DEEP SOUTH TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 230 AM CDT WED APR 17 2002 CONUS WX STORY IS XTRM HIGH TEMPS OVR EAST...WINTER REVISITS WEST...AS 1000-500MB THICKNESSES AT 531DM OVR PAC NW AND 570DM OVR OH VLY AND UPSTATE NY. H5 585DM HEIGHT RUNS FM WRN RIO GRANDE VLY TO FINGER LAKES OF CENTRAL NY. HERE IN VLY TNGT...LLVL JET HAS MIXED TO SFC...WITH SE WINDS AT 15 TO 25 MPH NOW. VAD WNDS FM KBRO SHOW 30KT S WNDS AT 1K FT...40 KT AT 2K FT. A TAD MIFFED AT CAUSE OF THESE STRONG EVENING WNDS AND THEIR DURATION...AS MSAS ANALYSIS DOES NOT RECOGNIZE THIS REALITY. ALTHOUGH SFC PGF NOTED FM W TO E ACROSS THE VLY...EXTENDING FM 1010MB LOW OVR ADJ MEX TO 1020 HIGH...LOWER WND SPEEDS ARE PREDICTED. RUC80 850MB ANALYSIS ALSO UNDERCUTS PGF AT THIS LVL...SHOWING SW WNDS OF 25KTS OVR DEEP S TX NOW. OTHER MYSTERIOUS WX PARAMETERS...OR GROSS UNDERESTIMATION OF TRUE PGF AT SFC AND 850MB MUST BE THE CULPRIT. MORE SPRING-TIME WX ON TAP FOR THE RIO GRANDE VLY...WITH GUSTY SE WINDS EACH DAY...AS A STRONG UPPER LEVEL LOW PRESSURE SYSTEM OVER THE NORTHWEST U.S. AND A RIDGE OVER THE SOUTHEAST KEEPS SFC LOW/HIGH COUPLET TIGHT. WITH THIS UPPER FLOW ORIENTATION...WEAK IMPULSES WL MOVE THRU THE FLOW NORTH OF THE RIO GRANDE VLY...INITIATING CONVECTION FM BIG BEND TO THE MS VLY...AS UPPER RIDGING FM THE SOUTH FORCES WX DYNAMICS AWAY FM THE RIO GRANDE VLY. PARTLY CLOUDY EARLY...BECOMING MOSTLY CLOUDY NIGHTS...BECOMING PARTLY CLOUDY AND BREEZY DURING AFTERNOONS. VERY PERSISTENT TEMP REGIME PROGD BY ALL MDLS WITH THIS UPPER PATTERN...WITH WRN VLY HIGHS 93 TO 97...BRO/HRL/MFE PM HIGHS 88 TO 93. SFC LOW DEVELOPS OVR TX PNHNDL THU...WITH WINDY WX ACROSS THE RIO GRANDE VLY THU (SE 20-30 MPH)...AND CONVECTION GENERATED BY DRY LINE DRIFTING EAST FRI NGT...CONFINED FM BIG BEND TO NRN TX. ALTHOUGH MDLS ARE ALL DIGGING THE UPPER LOW INTO THE SW FARTHER THAN THE 12Z RUN...THIS DEVIATION HAS LITTLE EFFECT ON OUR WX...WITH ALL MDLS CONFIDENT ON 588DM H5 HIGH CONTROLLING WX FM ITS CENTER IN THE BAY OF CAMPECHE. WL CONTINUE WITH OUR PERSISTENT WX PATTERN UNTIL STRONGER DYNAMICS ALOFT SHOW A NEED FOR CHANGE. LONG TERM...LOOKS LIKE A PROLONGED PERIOD OF S TO SE LOW LEVEL FLOW...WITH NO FROPAS EXPECTED...AND GULF RIDGING DOMINATING OUR SEMI-TROPICS. SOME FLATTENING OF THIS UPPER TROPICAL RIDGE NOTED OUT ONE WEEK FM TDY MAY ALLOW THE PRODUCTION OF RAINS IN DEEP S TX FOR THE END OF APR. LET'S HOPE! MARINE...WINDS AT SPI AND POR MARKEDLY LOWER THAN INLAND ATTM...AS MARINE ENVIRONMENT NEGATES MIXING OF LLVL JET. BOY020 REFLECTS A FAIRLY CONSTANT WND FLOW FM SE AT 14 TO 17 KTS. SEAS PERSIST AT 5 FT EVERY 7 SECS. ONSHORE FLOW CONTINUES FOR THE REST OF THE WEEK. SMALL CRAFT ADVISORIES MAY BE NEEDED FOR THE LAGUNA MADRE DURING THE AFTERNOONS...BUT THESE CONDITIONS WERE MARGINAL TUE PM...WITH SOUTH WNDS DURING PM HOURS AT 15 TO 20 KTS...WITH A MODERATE CHOP NOTED ON THE BAY FM PERSONAL OBSERVATION. SEAS OFFSHORE WILL ALSO BUILD TO NEAR SMALL CRAFT ADVISORY CRITERIA...DUE TO THE PERSISTENT SOUTHEAST WINDS OVER THE GULF FETCH. AN OCCASIONAL ADVISORY OFFSHORE MAY BE POSSIBLE THIS WEEK. PRELIMINARY NUMBERS FOR COORDINATION PURPOSES ONLY... BRO BB 089/073 089/074 089 00/00/00/00/00 HRL BB 091/071 092/072 092 00/00/00/00/00 MFE BB 092/071 093/072 093 00/00/00/00/00 RGC UU 094/068 095/069 095 00/00/00/00/00 SPI BB 082/075 082/076 082 00/00/00/00/00 SYNOPTIC...PHILO (58)/AVIATION-MARINE-MESO...MCGUIRE (55) INTERNET ADDRESS...WWW.SRH.NOAA.GOV/BRO .BRO...SCA TODAY FOR GMZ130. tx NORTHWEST CALIFORNIA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EUREKA CA 830 AM PDT WED APR 17 2002 NO UPDATES TO ZONE FORECASTS PLANNED AT THIS TIME...AS CURRENT FORECAST SEEMS TO HAVE SITUATION WELL IN HAND. RADAR AND SATELLITE CONTINUE TO SCATTERED SHOWERS ASSOCIATED WITH COLD POOL ALOFT. A CHECK OF THE LATEST RUC AND MESOETA MODEL DATA...ALONG WITH WATER VAPOR IMAGERY TRENDS COMPARED TO ETA AND AVN DATA...SHOWS UPPER LOW ALONG COAST OF WA AND WEAK 7H TROF SLIDING THROUGH TODAY. ANOTHER MID LEVEL TROUGH APPEARS TO BE POISED TO THE NORTH OF THE REGION...AND WILL LIKELY SWING THROUGH TONIGHT. OVERALL...A GRADUAL RISE IN HEIGHTS ALOFT EXPECTED TODAY AS UPPER RIDGE TO THE WEST EDGES VERY SLOWLY TOWARD COAST...ALSO A SLOW TREND FOR LOWERING RH ALOFT THROUGH TONIGHT AND INTO THU. EVEN SO...POOL OF COLD AIR ALOFT REMAINS OVER REGION ALONG WITH CYCLONIC FLOW ALOFT. GOES SOUNDER DATA FROM 13Z SHOWS 5H TEMPS ALONG 130W OF -19C...W OF CAPE MEDOCINO...AND -22C FURTHER N OFF N OREGON COAST. THIS INDICATES THE NORTHERN PORTION OF THE RIDGE MAY BE PUSHING EAST A LITTLE FASTER THAN MODELS INDICATE. FOR NW CALIF...MESOETA AND RUC CONTINUE TO GENERATE SCATTERED PRECIP IN SHOWERS TODAY AND TONIGHT...BUT AGAIN...OVERALL TREND COMPARED TO YESTERDAY SHOULD BE FOR SOME IMPROVEMENT...NOT AS COLD ALOFT SO SHOWERS NOT QUITE AS WIDESPREAD AND INTENSE AS WHAT THE REGION EXPERIENCED YESTERDAY. FORECAST HIGH TEMPS LOOK ON TRACK AS WELL. CWF...ONLY SLIGHT ADJUSTMENTS TO WINDS THIS MORNING. ADJUSTED SWELL DOWNWARD ABOUT A FOOT BASED ON BUOY TRENDS...BUT KEEPING FAIRLY CLOSE OVERALL TO WAVE WATCH III DATA. POPS CEC 84200 ACV/EKA 73200 UKI 32000 LORENS .EKA...SMALL CRAFT ADVISORY PT ST GEORGE TO PT ARENA OUT 60 NM. ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1040 AM CDT WED APR 17 2002 UPDATED ZONES AROUND 1530Z TO ADD SCATTERED THUNDERSTORMS SRN HALF OF FA AND LOWERED TEMPS SLIGHTLY IN NORTH. LSX AND PAH RADAR SHOWING SOME CONVECTIVE DEVELOPMENT ASSOCIATED WITH WEAK SHORT WAVE MOVING INTO REGION FROM ARKANSAS. WEAK CAP AND GOOD INSTABILITY WILL CONTINUE OVER SRN FA WHERE BOTH 12Z ETA AND RUC INDICATE THAT THE AREA BETWEEN ONGOING PCPN WILL FILL IN SOMEWHAT THROUGH MIDDLE AFTERNOON. BOUNDARY MOVING INTO NWRN FA A BIT MORE AGGRESSIVE THAN PREVIOUS PACKAGE SUGGESTED. WILL LOWER HIGHS SLIGHTLY FOR AREAS THAT WILL BE IN THE VICINITY OF AND BEHIND THE BOUNDARY. .ILX...NONE. $$ BARKER/MILLER il SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1207 PM EDT WED APR 17 2002 LINE OF WEAKENING SHOWERS WITH ISOLATED THUNDER NEAR THE OHIO BORDER WILL CLEAR SOUTHEAST LOWER WITHIN THE NEXT HOUR OR SO. ATTENTION THEN TURNS TO THE APPROACH OF THE SURFACE COLD FRONT...CURRENTLY EXTENDING FROM NEAR THE STRAITS TO AROUND CHICAGO. BOTH THE RUC-20 AND ETA-12 NOW INDICATE THAT THE SURFACE FRONT AND THETA-E RIDGE AT 850MB WILL STALL ACROSS THE SOUTHERN HALF OF THE FORECAST AREA LATE THIS AFTERNOON THEN REMAIN STATIONARY THROUGH TONIGHT. THE 700MB THETA-E RIDGE SAGS A BIT FARTHER SOUTH, HOWEVER, THE PRESENCE OF THETA-E ADVECTION AT 850MB, WITH AMPLE DRY ALOFT TONIGHT WILL AID IN PRESERVING STEEP MID-LEVEL LAPSE RATES IN THE VICINITY OF THE STATIONARY FRONT. EXPECT THAT SCATTERED SHOWERS AND THUNDERSTORMS WILL REDEVELOP ALONG THE FRONTAL ZONE LATE THIS AFTERNOON INTO THIS EVENING. RADIATIONAL COOLING AT THE TOP OF THE LOW-LEVEL MOIST LAYER WILL AID MAINTAINING THE MID-LEVEL INSTABILITY THROUGH THE NIGHT, SUGGESTING THAT THE CHANCE FOR CONVECTION WILL CONTINUE THROUGH THE OVERNIGHT HOURS, ESPECIALLY ALONG AND SOUTH OF INTERSTATE 69. THE FRONT WILL THEN RETREAT NORTHWARD AS A WARM FRONT THURSDAY, BUT MAY BE DELAYED SLIGHTLY, COMPARED TO THE ETA, BY THE COOLER AIR STREAMING OFF OF LAKE HURON. UPDATED PACKAGE ALREADY OUT, BUT ANTICIPATE ANOTHER UPDATE TO CHASE THE SHOWERS OUT IN AN HOUR OR SO. .DTX...NONE. MANN mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 929 AM EDT WED APR 17 2002 A HOT DAY IN STORE FOR E NC WITH NEAR RECORD HIGH TEMPS. LEE SIDE TROUGH ACROSS W PIEDMONT AT THE SFC AND UPPER RIDGE OVER MUCH OF THE E. USING 88/65 MODIFIED 12Z MHX SOUNDING HAS A CAPE OF 3189 J/KG WITH AN LI OF -8. VIL OF THE DAY IS IN THE MID 40S. ANY TSTMS THAT FORM TODAY COULD BE HEAVY RAIN PRODUCERS SINCE 0-6 KM STORM MOTION IS ONLY 4 KT. H85 THETA-E BULLSEYE IS OVER CNTRL NC LATE THIS AFTERNOON. USING RUC40 BEST CAPE THIS AFTERNOON WILL BE NEAR THE PAMLICO SOUND WHERE BEST SEABREEZE CONVERGENCE SHOULD BE. BEST CHANCE FOR TSTMS TODAY LOOKS TO BE THERE AND OVER THE COASTAL PLAIN. CURRENT FCST LOOKS ON TRACK AND DO NOT PLAN ON AN UPDATE. RECORD HIGH TEMPS TODAY: EWN 90/ HSE 82 / NCA 90 / NKT 88 / MARINE: NO CHANGES NEEDED TO GOING FCST AS LIGHT SW FLOW PERSISTS. .MHX...NONE WS/CTC nc SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO COLORADO 226 PM MDT WED APR 17 2002 ...VERY WINDY TO STRONG WINDS LIKELY TNGT AND THU AM... ...EXTREME FIRE BEHAVIOR LIKELY TNGT-THU AM... ...CHANGE IN THE SENSIBLE WX STARTING THU NGT THROUGH WEEKEND... CURRENTLY: COUPLE OF ULJ STREAMS TAKING AIM ON THE ROCKIES THIS AFTERNOON. FIRST...THERE IS THE SRN STREAM OVER DESERT SW WHICH SHOULD MOVED NEWD TOWARDS EXTREME SERN CO...WHILE THE NRN STREAM WAS DRIVING THROUGH THE GREAT BASIN PER WATER VAPOR IMAGERY LOOP. SFC CYCLOGENESIS STARTING TO DEVELOP IN WY PER METARS AND ISOLLOBARIC ANALYSIS. TNGT-THU: BOTH ULJ ADVANCE TOWARDS CNTRL ROCKIES/PLAINS TNGT. CYCLOGENESIS DEEPENS AROUND SERN WY THEN MOVES INTO THE NRN PLAINS BY THU. ONCE AGAIN...VIGOROUS SW-WLY FLOW PROGGED ACROSS THE CWFA. IN FACT...IT APPEARS THE PATTERN IS SIMILAR TO TUE LATE AM- AFTN...BUT DURING THE NGT-EARLY AM. PRESSURE GRADIENT TIGHTENS WITH DEEPENING CYCLONE TO THE N. VERY CONCERNED ABOUT THE ETA/MESO- ETA HAVING A RELATIVELY DEEP(800-700MB) 50-55KT JET CORE OVER SERN CO LATER TNGT. ALSO...POTENTIAL BORA WIND PATTERN FOR SERN CO MTNS/ADJACENT PLANS. MOD-STG 500MB CAA PROGGED BETWEEN 03Z-15Z. MID LEVEL WIND FLOW ORTHOGONAL TO THE SANGRE DE CRISTO/WET MTNS INCLUDING PIKES PEAK. POTENTIAL FOR A LITTLE MORE WIDESPREAD MOD- STG WIND GUSTS FOR SERN CO MTNS/PLAINS. SPEEDS...AS USUAL...WILL BE MARGINALLY AROUND THE WIND GUST WARNING CRITERION. THE LEE OF THE SANGRES/WET MTNS HAVE THE GREATEST POTENTIAL FOR WIND GUSTS TO 70 MPH IN THE MTNS AND AROUND 58 MPH ADJACENT PLAINS. LATEST RUC AND 18Z MESO-ETA HAVE GOOD CONTINUITY ON THIS POTENTIAL PATTERN. TOUCH CALL. PLAN TO HOIST HIGH WIND WARNING FOR 9PM TNGT-12PM THU FOR SERN CO MTNS/PLAINS. RED FLAG WARNING FOR MTNS CONTINUES UNTIL 12PM THU FOR STG WIND GUSTS AND CURRENT FIRES. POTENTIAL FOR PRECIPITATION PRETTY SLIM ALONG WITH ANY CLOUD COVER...EXCEPT FOR AROUND THE CONTDVD...TNGT THROUGH THU. WITH THE POTENTIAL FOR A DEEPLY MIXED BOUNDARY LAYER DURING THE NGT...TEMPS SHOULD BE MILD LIKE LAST MON NGT. MESO-ETA GRIDS HAS LOWS IN THE 50S SERN CO PLAINS. MOS MIGHT BE A LITTLE TOO COOL. ON THU...WINDS SHOULD DIMINISH AS PRESSURE GRADIENT WEAKENS... HOWEVER 500MB WINDS STILL AROUND 50KTS FROM THE W AND WINDS COULD PICK BACK UP IN THE AFTN DUE TO MIXING AND AS THE NEXT CDFNT ADVANCES FROM THE N INTO NERN CO. NO PRECIPITATION ON THE HORIZON THU. THU NGT: CHANGES IN THE OFFING THIS PD INTO THE WEEKEND. CDFNT RACES DOWN THE ERN CO HIGH PLAINS TOWARDS THE MTNS. MOISTURE PRETTY SHALLOW(850-700MB)....BUT MOIST(80-95%) BY FRI AM. ISENTROPIC UPGLIDE FCST ACROSS SERN CO...BUT LOW GRADE MOISTURE. THERE WILL LIKELY BE BETTER RH RECOVERY FOR MOST OF THE MTNS/PLAINS ON THU NGT. PLAN TO HAVE LOW POPS FOR TELLER/EL PASO COUNTIES LATE THU NGT. FRI-FRI NGT: SFC ANTICYCLONE DROPS INTO THE NRN PLAINS AND WRN US SYSTEM STARTS TO WEAKEN AND EJECT PIECES OF ENERGY. JUST ON THE SRN EDGE OF THE MOISTURE...SO AGAIN TOUGH CALL FOR PRECIPITATION. WILL MAINTAIN LOW POPS AND COOLER TEMPS/HIGHER RH LOOKS TO BE THE RULE AND NEEDED FOR FIRE WEATHER CONCERNS. SAT: ETA/AVN EJECT WEAK SHORTWAVES THROUGH THE SWLY FLOW...WHICH COULD BRING SOME RAIN/SNOW SHOWERS TO THE RGN. AGAIN...NOTHING REALLY TO GET EXCITED ABOUT. ETA EXTENSION HARDLY PRINTS OUT ANY QPF IN S CNTRL/SERN CO. COOLER TEMPS CONTINUE. SUN-WED: LAST OF THE WEAK SHORTWAVES MOVES THROUGH CO SUN WITH THE AVN DRYING OUT...WHICH SAYS A LOT FOR THE OVERLY MOIST(HERE IN THE SEMIARID DESERT) AVN. LITTLE CHANCE FOR PRECIPITATION WITH MODERATING TEMPS WILL BE THE PLAN. ECWMF RELOADS ANOTHER LOW IN THE DESERT SW FOR TUE...WHICH THE OTHER MODELS HARDLY HAVE ANYTHING. ECWMF HAS BEEN DOING A PRETTY GOOD JOB. TIME WILL TELL. NEAR CLIMO FOR DAYS 6-7. .PUB...RED FLAG WARMING FOR FIRE WEATHER ZONES 220>225(MTNS/SAN LUIS AND UPPER AR RVR VLYS) TONIGHT THROUGH 12PM THU. ...HIGH WIND WARNING...ZONES 65, 66, 67, 70>81...9PM WED THROUGH 12PM THU. METZE co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 220 PM EDT WED APR 17 2002 AS EXPECTED...GOOD CU FIELD SETTING UP OVER MUCH OF CWA...WITH WEST COAST...BIG BEND...PANHANDLE & EAST COAST SEA BREEZES BEGINNING. EXPECT MOST OF CONVECTION THIS AFTERNOON & EVENING TO BE FROM WEST & EAST COAST SEA BREEZES TO MEET JUST WEST OF GAINESVILLE NORTH TO NEAR VALDOSTA...WHERE 40% IN FORECAST. OVER REST OF CWA...A 20-30% CHANCE POP INTO EVENING WITH OVERALL MOIST & UNSTABLE ATMOSPHERE. AFTER SUNSET...CONVECTION WILL DISSIPATE. SURFACE & UPPER RIDGE PATTERN CONTINUES TO BE MAIN INFLUENCE ACROSS AREA. FOG THIS MORNING WAS NOT AS EXTENSIVE OR AS DENSE AS EXPECTED. MODELS AGAIN ARE HINTING AT MORE PATCHY THAN WIDESPREAD. RUC HAS VORT LOBE PUSHING OUT OF LOWER MS VALLEY INTO WEST TN & MS TO AL. THIS FEATURE MOVES NE & SHOULD HAVE NIL AFFECT ON CWA. MODELS CONTINUE PREVIOUS TREND. UPPER RIDGE DOES RETROGRADE TO SW...& FLATTENS AS SHORTWAVE ENERGY MOVES THROUGH PLAINS TO NE-E U.S. WHILE SURFACE RIDGE REMAINS IN PLACE DOMINATING CWA. MODEL SOUNDINGS ALSO CONTINUE TREND TO DRY OUT ATMOSPHERE & LOWER INSTABILITY FRIDAY THROUGH SUNDAY...AS WELL AS TIME-HEIGHT CROSS SECTIONS. CHANCES OF PATCHY DENSE FOG & LOW CLOUDS WILL ALSO CONTINUE AS LOWEST LEVELS OF ATMOSPHERE REMAIN MOIST. MORE OF A S-SW FLOW TAKES OVER BY FRIDAY & INTO WEEKEND WITH WINDS PICKING UP A BIT. THEN ON MONDAY...A COLD FRONT APPROACHES FROM NW...BRINGING A BETTER CHANCE OF SCATTERED SHOWERS & TSTMS. WILL CHANGE SLIGHT CHANCE TO CHANCE IN EXTEND FORECAST FOR MONDAY...THEN DRY & A BIT COOLER TUESDAY & WEDNESDAY. THEN ANOTHER BOUNDARY POSSIBLE LATE WEDNESDAY TO THURSDAY. FIRE WEATHER FORECAST: NO HEADLINES. RH VALUES REMAIN HIGH. MARINE FORECAST: NO HEADLINES. GRADIENT REMAINS LIGHT THROUGH THE WEEKEND. EXTENDED: NO CHANGES. MRF HAS A POSSIBLE COLD FRONT BY MID-WEEK...SO WENT WITH CHANCE POPS FOR WEDNESDAY. PRELIMINARY NUMBERS... TLH 062 088 063 089 232- PFN 066 082 066 082 232- DHN 064 087 064 088 232- ABY 063 087 064 088 232- VLD 064 088 064 089 3332 .TLH... .AL...NONE. .GA...NONE. .FL...NONE. MCT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 217 PM EST WED APR 17 2002 17Z SFC ANALYSIS SHOWS COLD FRONT EXTENDING FROM N LK MI...ACROSS SE WI AND NW IL THEN BACK ACROSS NORTHERN MO. WV LOOP SHOWS SHORT WAVE MOVING INTO TN VALLEY AND SETTING OFF SHRA/TSRA AHEAD OF IT. FRONT STILL EXPECTED TO REACH CWA THIS AFTERNOON AS 15Z RUC HAS IT ACROSS SW LWR MI AND NW IN BY 20Z. WILL STILL HAVE GOOD INSTABILITY AHEAD OF FRONT AS FCST SOUNDINGS SHOW CAPE GT 2000 AND LI -6. MAY GET JUST ENOUGH SFC CONVERGENCE TO WORK WITH THIS INSTABILITY TO TRIGGER SOME SCT SH/TSRA LATE THIS AFTERNOON/EARLY THIS EVENING. WILL MONITOR TRENDS TOWARD ISSUANCE TIME BUT PLAN FOR NOW IS TO INCLUDE A SMALL CHANCE POP FOR EARLY FIRST PERIOD. FRONT THEN TO LIFT NORTH OVERNIGHT AS DEVELOPING LOW MOVES INTO EASTERN SD. STRONG LLJ OVER CENTRAL PLAINS SHOULD SERVE AS FOCUS FOR CONVECTION TO OUR WEST TONIGHT. WITH WARM FRONT RIGHT ALONG OR JUST NORTH OF OUR NORTHERN CWA AND E/W ORIENTATION OF THICKNESSES SHOULD KEEP ANY MCS TYPE ACTIVITY NORTH OF OUR AREA. EXPECT THU TO BE SIMILAR TO TODAY WITH BREEZY...WARM AND UNSTABLE BUT NO REAL TRIGGER FOR ANY CONVECTION. ONLY POSSIBLE PLAYER WOULD BE ANY OUTFLOW BOUNDARIES FROM PREVIOUS NIGHT MCS ACTIVITY DRIFTING SOUTH INTO THE NORTHERN CWA. GIVEN CURRENT 40 POP WILL CONTINUE MENTION BUT LOWER TO 30. COLD FRONT THEN ARRIVE THU NIGHT AND WILL BE ACCOMPANIED BY STRONG UNIDIRECTIONAL FLOW CREATING POTENTIAL DAMAGING WINDS IN SQUALL LINE. MODELS DIFFER ON PASSAGE OF COLD FRONT FRI AS ETA TAKES FRONT THRU AND DOWN TO OH VALLEY BY 18Z FRI WHILE AVN STALLS FRONT BRIEFLY OVER SE CWA AND BRINGS SFC WAVE ALONG FRONT FRI BEFORE PUSHING SOUTH BY 12Z SAT. FOR NOW WILL CONTINUE WITH GOING FCST AND KEEP CHANCE POPS IN FOR FRI AND DRY FCST BY SAT. NO BIG DIFFERENCES IN GUIDANCE TEMPS AND GENERALLY FOLLOWED MAV TREND. 5H VORT/TROF SWINGS THRU THE LAKES SUN NGT AS SFC LO MOVS FROM LWR MS INTO TN VLY WITH SCT SHRA. SHRA DEPART MON MRNG AS HI PRES BUILDS IN MON AFTN THRU TUE. ON WED MRF BRINGS STRONG S/W AND SFC LO THRU THE LAKES. WED SYS LOOKS OVERDONE BUT STILL WORTH A MENTION OF PSBL SHRA. ECMWF QUITE A BIT WARMER THAN MRF IN OUTER PERIODS AND MRF MAY BE OVERDOING MID-WEEK COLD AIR PLUNGE SO WILL TEMPER MRF MOS TEMPS UPWARD. .IWX...NONE. JAL/12 in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 255 PM CDT WED APR 17 2002 IN THE SHORT TERM...SFC WARM FRONT LOCATED ACROSS NORTHERN MISSOURI THIS AFTERNOON AND MOVING TO THE NORTH. LARGE AREA OF CUMULUS ALONG AND SOUTH OF FRONT INDICATIVE OF CAP IN PLACE HOLDING WARM AND UNSTABLE AIR IN CHECK. NO GOOD INDICATION FOR DYNAMIC LIFT TO BREAK THE CAP AND BOTH RUC AND MESOETA SOUNDINGS SHOW CAP WEAKENING SOME BY 00Z. THERE IS A CHANCE FOR ISOLATED TSTMS ALONG FRONT THIS EVENING. OVERNIGHT AN AREA OF CLOUDINESS WILL SPREAD ACROSS THE REGION FROM THE SW IN RESPONSE TO WEAK ISENTROPIC LIFT. APPROACHING COLD FRONT IS EXPECTED TO SPREAD THUNDERSTORMS ACROSS THE REGION LATE THURS AFTN AND EVENING. FRONT PROGGED TO PUSH INTO S MO FRI MRNG BUT WILL HOLD ON TO LINGERING CHC SHWRS MAINLY S OF I-70 ON FRI AND FRI NIGHT. WEST COAST TROF GETS KICKED INTO THE THE PLAINS OVER THE WEEKEND KEEPING UNSETTLED WEATHER IN THE FORECAST. TEMPS WILL BE QUITE WARM ON BREEZY SOUTH WINDS BUT MORNING CLOUDINESS WILL BE A FACTOR IN HOW WARM WE CAN GET. WILL CONTINUE UPPER 80S FOR MOST AREAS AFTER MILD LOWS IN THE MID 60S. FRONT AND PCPN WILL LIMIT HEATING ON FRIDAY AND SATURDAY WITH HIGHS ONLY REACHING THE LOWER 60S. USED A CONSENSUS OF MOS FOR TEMPS...BUT LEANED TOWARD AVN VALUES. BROWNING DAYS 4-7 SUN-WED INTRODUCED CHC TRW/RW SUN AS MODEL SOLUTIONS SUGGEST MORE NORTHERN TRACK FOR SURFACE LOW ALONG WITH SOME UPR SUPRT. ALSO INSERTED CHC TRW/RW TUE AS MRF SHOWS UPR SUPRT AND PASSAGE OF CDFNT AS LOW MOVES THROUGH N OF CWA. TUE PRECIP SHOULD START AFTN AND END BY WED. NO CHGS TO TEMPS. WED TEMPS WRMR THAN MOS GUID AS HIR THCKNS SEEMS LKLY. MAXIMUK 1020 AM... DID A MINOR REVISION TO THE ZFP AND RDF PRODUCTS TO BRING AFTERNOON FORECAST MORE IN LINE WITH TEMPERATURE AND CLOUD TRENDS. ALSO REMOVED PRECIP FORECAST IN CHILLICOTHE AND MACON ZONE GROUP FOR TONIGHT. PC 330 AM... SATELLITE IMAGES AND SURFACE OBS PAINTING A PICTURE OF SPRING ACROSS THE MIDWEST THIS MORNING. LARGE TROUGH...ANCHORED OVER THE WEST COAST...CONTINUES TO SPIT S/WV DISTURBANCES ACROSS THE MIDWEST. A LINE OF THUNDERSTORMS FIRED ALONG THE DRY LINE IN CENTRAL KS OVERNIGHT AS UPPER LVL DYNAMICS SWUNG THROUGH THE MID MISSOURI RIVER BASIN. MOST OF THE THUNDER DIED BEFORE IT REACHED OUR CWA THIS MORNING...DUE TO THE STABILIZED AIR MASS FROM THE CLOUD COVER AND SHOWERS TUE AFTERNOON. A FEW THUNDERSTORMS DID POP UP IN THE NORTHWEST CORNER IN THE EARLY MORNING HOURS ALONG WHAT APPEARED TO BE THE SURFACE FRONT. MAIN PROBLEM WILL BE POPS OVER NEXT FEW DAYS. FOCUS IN THE SHORT TERM WILL BE WITH HOW...WHERE...AND WHEN THE "COLD" FRONT LAYS ACROSS MISSOURI TODAY AS THE ASSOCIATED LOW LIFTS INTO CANADA. DEWPOINTS HAVE BEGUN TO DROP IN THE EXTREME NW CORNER OF THE STATE AS WINDS SHIFT AROUND TO THE NW BEHIND THE SURFACE FRONT. THINKING IS THAT THE SURFACE FRONT COULD ALMOST GET SOUTH OF I-70 BY SUNRISE...WHICH IS FURTHER SOUTH THAN WHAT THE CURRENT SHORT RANGE MODELS SHOW...BUT THAT A SECOND S/WV MOVING OUT OF THE ROCKIES WILL QUICKLY MOVE THE BOUNDARY BACK TO THE NORTH TODAY WITH THE HELP OF A SRLY WIND. H85 50+ KT JET LOOKS TO NOSE ITS WAY BACK THROUGH EAST KS INTO THE NW CORNER OF MO BY 00Z THU. WITH A THETA-E AXIS OVER NORTH MISSOURI...I AM INCLINED TO PUSH UP THE RE-INTRODUCTION OF POPS INTO THE LATE AFTERNOON HOURS NORTH OF HWY 36. LOOKING INTO THU AFTERNOON THRU FRI MORNING...EXPECTING OUR SECOND S/WV LOW TO WEAKEN AS IT LIFTS ACROSS THE UPPER MIDWEST AND DRAGS ANOTHER "COLD" FRONT ACROSS THE PLAINS. THIS FRONT LOOKS TO ACTUALLY HAVE MUCH COOLER AIR BEHIND IT AS THE HIGH PRESSURE IS DESCENDING OUT OF CANADA. THE FOCUS FOR POPS LOOKS TO BE TO THE SOUTH OF OR CWA AS THIS SECOND COLD FRONT SAGS BACK TO THE SOUTH THU AFTERNOON AND BECOMES STATIONARY. I HAVE BUMPED POPS FOR THE SOUTH HALF OF THE CWA THU NIGHT/FRI MORNING AS ANY SHOWERS OR THUNDERSTORMS THAT DO FIRE ALONG THE FRONT COULD ADVECT NORTH. MOVING INTO THE WEEKEND AND BEYOND...MID RANGE MODELS POINTING TOWARDS THE STATIONARY FRONT TO OUR SOUTH HANGING OUT DOWN THERE AS THE CANADIAN HIGH TO OUR NORTH ROLES THROUGH THE UPPER MIDWEST. GOING FORECAST OF CHC -TSRA THROUGH 12Z SUN LOOKS GOOD AS SMALL DISTURBANCES RIDING ALONG THE STATIONARY FRONT COULD SET OF SOME SCATTERED CONVECTION. ADDITIONALLY...CLOUD COVER OVER THE STATE AND HIGH PRESSURE TO THE NORTH SHOULD KEEP TEMPS JUST BELLOW NORMAL THROUGH MON. THANKS TOP FOR COORDINATION... CUTTER .EAX... KS...NONE MO...NONE mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 300 PM CDT WED APR 17 2002 18Z SFC ANALYSIS SHOWED LOW PRESSURE DEVELOPING OVER WY WHILE STALLED BOUNDRY ACROSS NRN KS AND NRN MO WAS STARTING TO LIFT NORTH. SHARP LOW LEVEL MOISTURE GRADIENT IN PLACE OVER EASTERN KANSAS. COMBINATION OF INCREASING SOUTH FLOW AND ADVECTION OF THE LOW LEVEL MOISTURE INTO THE CWA TONIGHT SHOULD PREVENT TEMPS FROM FALLING OFF MUCH OVERNIGHT SO HAVE BOOSTED MINS TO THE 60S AS A RESULT. WILL CONTINUE WITH MENTION OF SLGT CHC THUNDER TONIGHT AS WESTERN SYSTEM GETS ORGANIZED AND WARM FRONT LIFTS ACROSS THE CWA. MODELS SIMILAR IN TAKING SFC LOW ACROSS SD TONIGHT AND INTO SWRN MN ON THURSDAY WITH FRONT MOVING THROUGH SERN PARTS OF THE CWA DURING MAX HEATING. ETA INDICATES BEST INSTABILITY BY THAT TIME EAST OF THE AREA BUT WILL NONETHELESS STAY WITH SOME LOW POPS AS FRONT MOVES THROUGH AND COLD ADVECTION KICKS IN OVER THE AREA. SOME MODEL DIFFERENCES IN EXTENDED PERIOD AS EXTENDED ETA SHOWING H85 BOUNDRY LITTLE FURTHER NORTH THAN AVN IN 72-84HRS SO WILL MENTION LOW POPS SAT AFTN/SAT NIGHT. BASED ON NEW AVN WILL ALSO TAKE OUT POPS FOR SUNDAY AND MONDAY AND LEAVE CHANCE IN FOR TUE/WED. TEMPERATURES WILL AGAIN PRESENT A CHALLENGE AS FRONT MOVES THROUGH ON THURSDAY WITH STRONG CONTRAST EITHER SIDE OF FRONT. WILL LEAN TOWARD WARMER ETA AT THIS TIME WITH SERN AREAS REACHING UPPER 80S. MUCH COOLER THURSDAY NIGHT INTO THE WEEKEND AS HIGH BUILDS DOWN WITH SEASONAL READINGS REMAINDER OF EXTENDED PERIOD. FOBERT ... 330 AM CDT WED APR 17 2002 FORECAST CHALLENGES...RETURN OF SFC FNT AND DVLPMENT OF TSRA THIS AFTERNOON AND TONIGHT. SYNOPSIS...AFTER AN ACTIVE SVR WX NIGHT FOR THE FCST AREA...NEGATIVELY TILTED TROF SWEEPS NORTHEAST...SHIFTING THE TSRA TO MN-IA-ERN KS. SFC FNT PUSHING THRU SW IA NOW AND DEWPOINTS HAVE FALLEN TO THE 30S/40S BEHIND THE FNT AND THE WNDS HAVE DIMINISHED SIGNIFICANTLY. FORECAST...ERLY THIS AM MINOR SHORTWAVE FCST BY ETA TO PRODUCE PRECIP...HOWEVER SHORT TERM AVN/RUC DRY. STLT INDICATING STG DRYING AND SUBSIDENCE AND WILL KEEP VERY SHORT TERM FCST DRY. MAIN UPR LOW OVR WA CONSISTENTLY FCST BY BOTH THE ETA/AVN TO WEAKEN AND SPLIT INTO TWO LOWS NR OR AND MT BY 06Z TONIGHT. SHORT TERM FCST INVOLVES SFC FNT KS/MO THAT PUSHES N INTO SE NEB/SRN IA LATE TAF. MODELS DIFFER ON THE LOCATION OF THE SFC LO AT 00Z WITH THE ETA/AVN SIMILAR OVR ERN WY AND THE NGM FARTHER N OVR ERN MT. NGM CONTINUES NWD BIAS AT 12Z AS ETA/AVN HAS THE SFC LO OVR ERN SD AND SFC FNT INTO ERN NEB. MID DAY THU THE FNT EXITS THE FCST AREA AND SFC HI PRES BUILDS IN FM MT. HI PRES RMNS OVR THE FCST AREA WELL INTO THE EXTENDED. DAYS 1 AND 2...MODEL TRENDS CONTINUE TO WEAKEN SHORT WAVE TROF AND ETA SEEMS TO HANDLE THIS BEST. DAY1 SPC OUTLOOK HAS ERN NEB AND WRN IA IN SLGHT RISK FOR DAY 1 VALID THRU 12Z 4/18. WAA/INSTABILITY/FAVORABLE SHEAR PROFILES DEVELOP LATE THIS AFT AND INCREASES THIS EVE. CAPE VALUES INCREASE TO 1-2K J/KG ACRS SE NEB TAF AND 2-3K J/KG THIS EVE. HAVE INCLUDED CHC FOR TSRA LATE TAF SE AND ALL OF THE FCST AREA TON AND LEFT THU DRY. TEMPERATURES TAF MID 70S N TO LOWER 80S S. S/SE WINDS TO INCREASE LATE THIS AFT AND EVE INTO THE BREEZY CATEGORY. DURING THE DAY THE SFC BOUNDARY PUSHES ACRS THE FCST AREA. FOR NOW HAVE MAINLY GONE DRY FOR THE REST OF THU/FRI AS THE SFC BOUNDARY/MID LEVEL WAA AFFECTS LOCATIONS FARTHER S. EXTENDED...SAT-TUES. SFC HI PRES AND NE FLO IS FCST FOR THE AREA SAT AND SUN. THERE ARE SOME TIMING DIFFERENCES WITH THE NEW MRF. THE OLD MRF HAD 30/40 POPS FOR SEVERAL DAYS. THE NEW MRF STILL HAS 30/40 POPS...HOWEVER...HAS THE GREATEST CHC PRECP SUN AND WED. ZAPOTOCNY IF YOU HAVE COMMENTS ON THE NEW FORECAST DISCUSSION FORMAT...PLEASE E-MAIL THEM TO W-OAX.WEBMASTER@NOAA.GOV OR CALL DAVE THEOPHILUS AT 402 359-5166. .OMA...NONE. FOBERT ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 313 PM CDT WED APR 17 2002 MAIN QUESTION IN THE SHORT TERM IS CHANCE FOR CONVECTIVE DEVELOPMENT ON THE DRYLINE. THERE HAVE BEEN A ECHOES CYCLING IN THE EASTERN TIER OF COUNTIES OF THE TEXAS PANHANDLE... BUT NONE HAVE TAKEN HOLD YET. CONVERGENCE IS NOT VERY STRONG WITH NO BACKED WINDS TO THE EAST... BUT WILL HAVE TO CONTINUE TO WATCH. LATEST RUC AND MESOETA DO SHOW PRECIP BREAKING OUT IN NORTHWEST OKLAHOMA BY 00Z AND ALONG THE DRYLINE BY 06Z. MESOETA ACTUALLY BRINGS THE PRECIP INTO CENTRAL OKLAHOMA OVERNIGHT. SPECIAL 20Z SOUNDING MAY ALSO SHED SOME LIGHT ON THE THERMODYNAMIC STRUCTURE... SO MAY MAKE A LAST MINUTE CHANCE. BUT WILL KEEP PRELIM 20S IN THE EVENING. CHANCE FOR PRECIP INCREASES THURSDAY NIGHT AND FRIDAY AS SURFACE FRONT MOVES INTO THE AREA. WILL MAINTAIN THE HIGH POPS THURSDAY NIGHT THROUGH FRIDAY NIGHT WITH THE FRONT IN THE VICINITY. MODELS SHOW FRONT MAY BE MOVE THROUGH SOUTHEAST SECTIONS LATER THAN FORECAST... SO WILL BUMP TEMPS UP A TOUCH IN THE SOUTHEAST ON SATURDAY. ...SPEG. OKC 66 82 62 72 / 20 20 50 60 HBR 64 83 60 73 / 20 20 30 50 SPS 68 85 63 79 / 20 20 30 50 GAG 60 88 47 66 / 20 20 30 50 PNC 66 83 58 68 / 20 20 50 60 DUA 67 85 66 78 / 20 20 50 60 .OUN... OK...NONE. TX...NONE. ok