AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 950 PM CDT FRI AUG 13 2004 .DISCUSSION... FORECAST TONIGHT MAINTAINS EMPHASIS ON LOW TEMPS. QPF IN RUC APPEARS TOO FAST AND QUITE OVERDONE AS -SHRA ALONG BACK EDGE OF DEEPER COLD POOL ALOFT OVER CNTRL MN ARE WEAKENING ON KMPX AND KFSD WSR88D WITH DIURNAL TREND. WILL KEEP OUT ANY MENTION OF PCPN GIVEN THIS. OTHER FORECAST ISSUE IS TEMPS WHICH WILL ONCE AGAIN PUSH TO NEAR RECORD LOWS TONIGHT. ADJUSTED SKY AND WIND GRIDS TO CURRENT TRENDS. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ MR ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 850 PM EDT FRI AUG 13 2004 ...EVENING UPDATE... CLOUDS PERSIST ACROSS THE OH/TN RIVER VALLEYS THIS EVENING, ALTHOUGH COVERAGE AND OPACITY NOT AS EXTENSIVE AS LAST NIGHT, WITH SOME DECENT BREAKS AROUND KBWG AREA. OVERALL TREND TOWARD P/CLOUDY, OR EVEN M/CLEAR, SKIES SHOULD CONTINUE OVERNIGHT. MIGHT HAVE A CHANCE TO SEE SOME RESIDUAL PERSEID METEORS? TEMPS ON TRACK FOR ANOTHER NIGHT OF NEAR RECORD MINIMA, BEFORE MODERATION BEGINS THIS WEEKEND ASSOC WITH RISING THICKNESSES. GFS MOS AND THE RUC VSBY PRODUCT SUGGEST SOME PATCHY FOG ACROSS PARTS OF KY BY SUNRISE. THINK AREAS FROM KLEX DOWN TOWARD KSME HAVE BEST CHCS, COINCIDENT WITH HIGHER SFC DEW POINTS AND LOWER DAYTIME MAXIMA TODAY DUE TO THICKER CLOUD COVER. XXV && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1142 AM EDT FRI AUG 13 2004 .UPDATED... THE GRIDS LOOK FINE FOR THIS AFTERNOON SO NO CHANGE IS PLANNED IN THE FORECAST. THE SOUNDINGS AT 12Z FROM DTX SHOWED A STRONG CAP NEAR 700MB WHILE THE SOUNDINGS AT GRB AND APX DID NOW SHOW A CAP ANYWHERE NEAR THAT STRENGTH. THE CYCLONIC CIRCULATION CAN BE SEEN CLEARLY ON THE VIS SAT LOOPS AS THE CLOUDS OVER ONTARIO EAST OF DETROIT AREA MOVING TO THE NORTH WHILE THE CLOUDS OVER LAKE MICHIGAN ARE MOVING SOUTH. AS THE 500MB LOW SLOWLY SHIFTS NORTH NORTHEAST FROM LK HURON AT 15Z TO NORTH OF GEORGIAN BAY THE 925MB...850MB AND 700MB HEIGHTS RISE AND WITH THAT THE TEMPERATURES AT THOSE LEVELS WARM THROUGH THE DAY. THE 850MB LI INDEX REMAINS POSITIVE ON THE RUC THROUGH THE AFTERNOON. EVEN SO...THERE IS DEEP MOISTURE AS ALL THREE WESTERN GREAT LAKE SOUNDING SHOW HIGH RELATIVE HUMIDITY THROUGH 10000 FT AND THE 15Z RUC SHOWS THAT MOISTURE WILL REMAIN (SLOWLY DECREASING WITH TIME AS THE HEIGHTS RISE AND AIR WARMS FROM SUBSIDENCE FROM THE RISING HEIGHTS). WITH THE LAKE STILL NEAR 18C AND THE 850 MB TEMPERATURES NEAR 5C...THAT 13C DELTA BETWEEN THE LAKE AND 850MB IS STILL THERE AND SO IS THE DEEP MOISTURE. THUS SHOWERS WILL CONTINUE. AFTERNOON SOUNDING FROM THE ETA12 SUGGEST WITH A SURFACE TEMP OF 64F AND DEW POINT OF 54F WE WOULD HAVE EQUAL LVL OF 28953FT AND A -.2 SFC BASED LI NEAR LANSING. IF ONE LOWERS THE DEW POINT TO 52F THE EQUIL LVL DROPS TO 12000FT. HOWEVER THE CLOUD TOPS ARE STILL NEAR 34000FT. ONE WAY OR THE OTHER IT SHOULD BE POSSIBLE TO GET TO 64F TODAY NEAR LANSING. THUS WILL KEEP THE SHOWERS GOING IN THE ZONES FOR THIS AFTERNOON. MAY HAVE TO WATCH FOR THUNDERSTORMS IF DEW POINTS STAY MUCH ABOVE 55F THOUGH AS TEMPERATURES RISE NEAR 65F. NOTE...LIKELY WILL PUT OUT PNS THIS AFTERNOON FOR COLD WEATHER. IF GRR HAS 4 DAYS IN A ROW WITH HIGHS BELOW 70F... WE HAVE 3 SO FAR AND LIKELY TODAY WILL MAKE IT FOUR... THIS WILL PUT GRR IN SECOND PLACE FOR THE LONGEST PERIOD OF HIGHS CONTINUOUSLY BELOW 70F BETWEEN JULY 1 AND AUGUST 31 FOR OUR PERIOD OF RECORD (1880 TO 2004). MKG WOULD BE IN 7TH PLACE WITH TODAY AND 5TH PLACE IF MKG CAN STAY BELOW 70F SATURDAY (NOT OUT OF THE QUESTION) && .GRR WATCHES/WARNINGS/ADVISORIES...SMALL CRAFT ADVISORY IN EFFECT FOR NEARSHORE WATERS OF LAKE MICHIGAN FROM NEW BUFFALO TO SOUTH HAVEN THIS MORNING. $$ WDM mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1052 AM EDT FRI AUG 13 2004 .DISCUSSION... WATER VAPOR IMAGERY AND RUC ANALYSIS CONTINUE TO SHOW A HIGHLY AMPLIFIED AUG PATTERN WITH RIDGE EXTENDING N THRU THE WRN CONUS AND A TROF DOWNSTREAM FROM HUDSON BAY S THRU THE GREAT LAKES. AT THE SFC...WRN RIDGE IS SUPPORTING BROAD HIGH PRES OVER THE NRN PLAINS AND SCNTRL CANADA WHICH IS RESULTING IN LIGHT NRLY FLOW OVER THE FCST AREA. BAND OF CLOUDS THAT WAS OVER NRN ONTARIO 24HRS AGO HAS SLIPPED S AND IS JUST N OF LAKE SUPERIOR THIS MORNING. THESE CLOUDS WON'T BE AN ISSUE HERE TODAY AS THEY DRIFT S. GOING FCST FOR TODAY IS IN GREAT SHAPE. WITH MIXING TO AROUND 800MB THIS AFTN...12Z KINL/KGRB SOUNDINGS SUGGEST HIGHS SHOULD TOP OUT IN THE MID 60S TO ABOUT 70. THIS IS INLINE WITH GOING FCST...SO NO REAL CHANGES PLANNED FOR TEMPS. IN ADDITION TO SCT MID/HIGH CLOUDS...DO EXPECT SOME CU TO FORM...BUT IT SHOULD NOT BE AS WIDESPREAD AS YESTERDAY SINCE THERE IS LESS BOUNDARY LAYER MOISTURE AVBL. ALSO... ETA/RUC FCST SOUNDINGS SHOW INCREASING DWPT DEPRESSIONS IN THE LOWER LAYERS THIS AFTN...SUGGESTING LESS CU DEVELOPMENT. ZFP LOOKS FINE...SO NO UPDATE NEEDED AT THIS POINT. ONLY A FEW MINOR ADJUSTMENTS TO THE GRIDS ARE PLANNED. && .PREV DISCUSSION... ONLY REAL FORECAST CONCERNS ARE TEMPERATURES OVER THE NEXT FEW DAYS (AS WE UNDERGO A GRADUAL WARMING TREND)...AND POTENTIAL FOR SOME FROST AGAIN TONIGHT. TONIGHT...RIDGE AXIS BUILDS OVERHEAD...WHICH SHOULD ALLOW FOR WINDS TO GO CALM IN THE CENTRAL U P AS WELL. HOWEVER...MAY NOT SEE TEMPS QUITE AS COLD AS TONIGHT FOR A FEW REASONS. AFTN DEWPTS SHOULD NOT BOTTOM OUT QUITE AS LOW AS YESTERDAY (PER UPSTREAM SFC OBS/HIGHER 850MB DEWPTS TO MIX)...THE AMS OVERALL WILL MODERATE SLIGHTLY TODAY...AND THERE IS THE POSSIBILITY OF SOME MID CLOUD SPREADING IN FROM THE NORTH (AS IS THE CASE IN ONTARIO RIGHT NOW... PER A REGION OF 300K ISENTROPIC LIFT WHICH WILL SAG SOUTHWARD). SO...WILL TWEAK TEMPS UP A BIT IN THE GRIDS (TO A LOW OF 37F INLAND)...BUT KEEP MENTION OF PATCHY FROST. MAY BE MORE OF A DEW/ SHALLOW FOG SCENARIO...BUT BASED ON THE CURRENT NIGHT CANNOT RULE OUT A LITTLE FROST. EITHER WAY THESE TEMPS ARE WELL BELOW GUIDANCE. WARMING CONTINUES INTO SATURDAY AS RETURN FLOW KICKS IN...THOUGH IT APPEARS WEAK ENOUGH TO ALLOW FOR A LAKE SUPERIOR BREEZE. ETA FCST SOUNDINGS SHOW A STRONG CAP DEVELOPING AROUND 630MB AS WE GET INTO SOME MID LEVEL RIDGING...AND WITH THE DRY AMS STILL IN PLACE... SHOULD AGAIN SEE ONLY SOME AFTN CU. AS PRESSURE FALLS TO OUR NORTH IN RESPONSE TO AN APPROACHING SHORTWAVE...AN INCREASED WIND SAT NIGHT WILL RESULT IN MUCH WARMER OVERNIGHT LOWS. 00Z RUNS AGREE IN KEEPING SUNDAY DRY...AND HOLDING PCPN OUT IN THE WESTERN U P UNTIL LATE SUNDAY NIGHT. TREND IS TO KEEP THE UPPER TROF OVER THE GREAT LAKES A BIT LONGER...WITH CHARLEY RIDING UP THE EASTERN STATES...AND AS A RESULT THE ETA/GFS EACH DIG THE NEXT SHORTWAVE A LITTLE FURTHER WEST. LOOKS AS IF BEST CHANCE OF CONVECTION SUN NIGHT/MON MAY BE ACROSS THE UPPER MISSISSIPPI VALLEY...BUT LOW CHANCE POPS FOR US DURING THIS TIME STILL LOOK GOOD. HAVE MADE NO CHANGES TO THE EXTENDED. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON (DISCUSSION) JKL (PREV DISCUSSION) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1040 AM EDT FRI AUG 13 2004 .UPDATE... THE GRIDS ARE IN GOOD SHAPE AND NO UPDATE PLANNED AT THIS TIME. VERY INTERESTING PATTERN WE ARE IN...SIMILAR TO WHAT WE MAY FIND IN LATE SEPTEMBER INTO OCTOBER. NEARLY A FULL LATITUDE TROF ACROSS THE EASTERN CONUS WITH HURRICANE CHARLEY GRABBING MOST OF THE ATTENTION. NICE CONVERGENT BAND ACROSS LAKE HURON ENTERING INTO SAGINAW BAY WITH ANOTHER BAND TRYING TO DEVELOP ALONG THE NEARSHORE WATERS OF LAKE HURON. ACTIVITY IN SAGINAW BAY CONTINUES TO PULSE UP AND AFTER CALLING OUR COAST GUARD ON PATROL...NO REPORTS OF H2O-SPOUTS AT THIS TIME. RUC13/ETA12 DID A FAIRLY GOOD JOB THIS MORNING SHOWING WHERE THE BEST CONVERGENCE FIELDS SET UP AND THESE MODELS SUGGEST A GRADUAL WEAKENING AFTER THE NOON HOUR AS DIURNAL ASPECT TENDS TO DISRUPT ORGANIZED BANDS OVER THE WATER (OUTSIDE OF STRONG COLD ADVECTION). H2O VAPOR LOOP SHOWS MAIN MID LEVEL WAVE WAS ROTATING NORTH EAST OF LAKE HURON WITH A HINT OF SOME FEATURE ACROSS WESTERN SECTIONS OF THE STATE. BASED ON OUR 12Z SOUNDING WE HAVE A STRONG CAP AT 700MB WITH A WEAKER CAP NOTED UPSTREAM IN APX. THIS SHOULD BE ENOUGH FOR SOME SCATTERED SHOWERS THIS AFTERNOON. WITH AMPLE MOISTURE IN THE LOW LEVELS AND ANY SUNSHINE WE SEE WILL LIKELY BE SELF-DESTRUCTIVE... WE WILL MAINTAIN THE CLOUD FESTIVAL AND KEEP TEMPS BELOW NORMAL. SPEAKING OF TEMPS...WE HAVE YET TO REACH 90 THIS MONTH. WE CAME CLOSE EARLY IN THE MONTH WITH UPPER 80S...BUT IT HAS BEEN A DOWNWARD TREND SINCE THEN AND GLANCE OF THE NEW LONG RANGE MODELS...NO END IN SITE. BGM && .PREV DISCUSSION... ISSUED AT 225 AM EDT RECORD COLD TEMPERATURES YESTERDAY AT BOTH FLINT AND DETROIT. THE AVERAGE DAILY TEMPERATURE AT DETROIT METRO WAS 59 DEGREES YESTERDAY (AUGUST 12TH). THIS BREAKS THE PREVIOUS RECORD OF 60 DEGREES SET IN 1903. THE AVERAGE DAILY TEMPERATURE AT FLINT WAS 55 DEGREES YESTERDAY (AUGUST 12TH). THIS BREAKS THE PREVIOUS RECORD OF 57 DEGREES SET IN 1967. DEEP UPPER LOW OVER SOUTHERN LOWER MICHIGAN THIS MORNING. THIS SYSTEM WILL SLOWLY LIFT OFF TO THE NORTHEAST...ALLOWING FOR A SLOW WARMUP THROUGH THE WEEKEND. CLOUDS WILL ALSO BECOME LESS PREVALENT...AS THE ATMOSPHERE DRIES OUT. 1000 TO 500 MB RELATIVE HUMIDITY NEAR 80 PERCENT THIS MORNING EXPECTED TO BE CUT IN HALF BY SUNDAY NIGHT. HOWEVER...THE OVERALL PATTERN...WESTERN RIDGE/EASTERN TROUGH...WILL CONTINUE INTO AT LEAST EARLY NEXT WEEK. THUS...EXPECT TEMPERATURES TO REMAIN BELOW NORMAL. IN THE MEANTIME...ABUNDANT CLOUD COVER TODAY WILL LIKELY KEEP TEMPERATURES FROM HITTING 70 DEGREES AGAIN. MESOETA 1000 TO 850 MB THICKNESSES DO INDICATE SLIGHTLY WARMER TEMPERATURES TODAY COMPARED TO YESTERDAY. LINGERING INVERTED SURFACE TROUGH...COUPLED WITH STEEPENING LOW LEVEL RAPES RATES DURING THE DAY SHOULD BE ENOUGH FOR A FEW SHOWERS. 00Z MESOETA INDICATING 100 TO 200 J/KG OF CAPE TODAY. NOT TO MENTION ONGOING LAKE EFFECT SHOWERS OFF OF LAKE HURON OVER THE TRI-CITIES/SAGINAW BAY REGION. THE STRONG SURFACE HIGH OVER THE NORTHERN PLAINS WILL BEGIN TO BUILD INTO THE GREAT LAKES REGION TONIGHT...ALLOWING THE LOW LEVEL FLOW TO BACK TO THE NORTH-NORTHWEST. WITH NORTHERLY FLOW...WILL STILL HAVE TO ACCOUNT FOR THE POSSIBILITY OF A FEW LAKE EFFECT SHOWERS ACROSS THE THUMB REGION TONIGHT AND INTO SATURDAY MORNING...AS 850 MB TEMPS REMAIN IN THE 5 TO 6 C RANGE AND INVERSION HEIGHTS REMAIN HIGH (8000 FEET OR HIGHER). EXPECTING ANY LAKE EFFECT ACTIVITY TO END BY SATURDAY AFTERNOON...AS 850 MB TEMPS MODIFY AND ENOUGH LOW LEVEL DRIER AIR WORKS INTO THE REGION. MULTIPLE SHORTWAVES EVIDENT ON THE WATER VAPOR IMAGERY OVER CENTRAL CANADA/NORTH CENTRAL CONUS TO CONTINUE TO DIVE SOUTHWARD...CARVING OUT A POSSIBLE CLOSED UPPER LOW OVER THE WESTERN OHIO VALLEY BY SUNDAY MORNING...PER 00Z GFS. THIS POSSIBLE CLOSED CIRCULATION IS STILL CONTINGENT ON HOW HURRICANE CHARLEY INTERACTS WITH THE EASTERN CONUS TROUGH. MAY JUST HAVE THE LARGE SCALE TROUGH AXIS CENTERED OVER GREAT LAKES REGION...PER CANADIAN. EITHER WAY...COUNTING ON THE UPPER LEVEL DIVERGENT FLOW TO REMAIN EAST AND SOUTH OF THE SOUTHERN LAKES REGION...KEEPING SOUTHEAST MICHIGAN DRY...AS THE LARGE SURFACE HIGH MAINTAINS CONTROL. NO CHANGES TO THE MAXES FOR SATURDAY AND SUNDAY...AS THEY ARE IN LINE WITH LATEST GFS MOS GUIDANCE. OBVIOUSLY...WE WILL NEED TO SEE SOME SUNSHINE ON SATURDAY...OR ELSE WE WILL BE STUCK IN THE UPPER 60S ONCE AGAIN. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && SF $$ EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE ALBANY NY 1105 AM EDT FRI AUG 13 2004 .SHORT TERM (REST OF TODAY)... WEAK WAVE OF LOW PRESSURE THAT DEVELOPED ALONG A STATIONARY FRONT OVER CNTRL NY COUPLED WITH A 850 THETA-E RIDGE WITH A STRONG LOW-LEVEL JET BROUGHT THE HEAVY RAINFALL TO THE FCST AREA THIS MORNING. UPDATE IS HEAVILY BASED UPON THE LATEST KENX RADAR LOOP AND THE LATEST IR/VISIBLE SATELLITE IMAGERY. RAINFALL HAS ENDED ACROSS MOST OF THE ALY CWA ...EXCEPT ACROSS THE SRN ADIRONDACKS AND A LINE OF ENHANCED SHOWERS AND POSSIBLY A FEW RUMBLES OF THUNDER OVER THE TACONICS/MID HUDSON VALLEY/BERKSHIRES/SRN VT. THIS APPEARS TO BE ASSOCIATED WITH A H500 VORT MAX SHOWN ON THE LATEST RUN OF THE RUC MODEL. GOOD AREA OF ANTICYCLONIC VORTICITY ADVECTION(NVA) MOVING THROUGH ERN PA. HAVE CUT THE POPS DOWN TO HIGH CHANCE WITH A MENTION OF SCATTERED SHOWERS AND THUNDERSTORMS FOR THE AFTERNOON. SATELLITE PICTURE CONTINUES TO SHOW A FEW BREAKS IN THE CLOUDS OVER CTRL PA/ERN NY. THE LATEST IR PICTURE SHOWS THE REMNANTS OF BONNIE JUST OFF THE DELMARVA PENINSULA. THIS TREND NOW CAPTURED BY 12Z ETA AND 06Z GFS KEEPS THE BULK OF THE PRECIPITATION TO THE EAST OF THE ALY FCST AREA. HAVE RAISED TEMPS A FEW DEGREES TOO. 12Z ALY SOUNDING CONTINUES TO THE TROPICAL LONG AND SKINNY PROFILE WITH PW-VALUE OF 1.74"...SBCAPE OF 440 J/KG AND S/SW FLOW VEERING IN THE LOWER-MID-LEVELS...SO WOULDN'T RULE OUT HEAVY DOWNPOURS WITH ANY CONVECTIVE DEVELOPMENT IN TROPICAL ATMOSPHERE. && .HYDROLOGY... FLOOD WATCH CONTINUES AT LEAST INTO THE AFTERNOON. THE GROUND ACROSS THE FCST AREA IS EXTREMELY SATURATED WITH GENERALLY 1 TO 4 INCHES HAVE FALLEN OVER THE PAST 24 HOURS. 4.48" OF RAIN FELL AT SLIDE MOUNTAIN IN ULSTER CO. SEE THE LATEST HYDALB. ANY ADDITIONAL RAINFALL WILL CAUSE PROBLEMS FOR THE STREAMS...CREEKS AND SMALL RIVERS. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH CTZ001-013 THROUGH 6 PM FRIDAY. MA...FLOOD WATCH MAZ001-025 THROUGH 6 PM FRIDAY. NY...FLOOD WATCH NYZ032-033-038>043-047>054-058>061-063>066-082>084 THROUGH 6 PM FRIDAY. VT...FLOOD WATCH VTZ013>015 THROUGH 6 PM FRIDAY. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 515 AM EDT FRI AUG 13 2004 SHORT TERM (TODAY THROUGH SUNDAY)... STILL HAVE TO DEAL WITH AREA OF RAIN MOVING NORTHWARD FROM PENNSYLVANIA THROUGH THIS MORNING. GOOD NEWS IS THAT HEAVY RAIN ASSOCIATED WITH TS BONNIE WILL GENERALLY PASS EAST OF OUR FORECAST AREA. MOST LIKELY ZONES AFFECTED WILL BE OUR NEW ENGLAND ZONES. LOOKING FOR A BREAK IN THE ACTION FROM THIS EVENING THROUGH SATURDAY EVENING THEN RAIN FROM HURRICANE CHARLIE WILL BEGIN TO SPREAD INTO THE REGION. SOME QUESTION ABOUT QPF HERE. GFS80 KEEPS MOST OF AREA BETWEEN TWO BULLSEYES OF HEAVY RAIN WHILE THE ETA GIVES US A DIRECT HIT LATE SATURDAY NIGHT AND SUNDAY. LONG TERM (SUNDAY NIGHT THROUGH THURSDAY)... DID NOT CHANGE ANYTHING HERE. SO WILL SUBMIT PREVIOUS LT DISCUSSION. AFTER CHARLEY MOVES THROUGH...HIGH PRESSURE WITH WARM AND HUMID AIR TAKES HOLD FOR SEVERAL DAYS. HOWEVER...WEAK UPPER LEVEL DISTURBANCES ARE ALSO FORECAST TO MOVE THROUGH THE REGION MONDAY THROUGH WEDNESDAY. AT THIS POINT WILL LEAVE OUT THE CHANCE OF SHOWERS FOR THIS PERIOD AND WAIT UNTIL THE NEXT COLD FRONT APPROACHES LATE THURSDAY AND THURSDAY NIGHT BEFORE INCLUDING A CHANCE OF SHOWERS IN THE FORECAST AGAIN. AVIATION... THE REMNANTS OF TROPICAL STORM BONNIE WILL APPROACH THE AREA TONIGHT. CEILINGS AND VISIBILITIES WILL DROP TO IFR AND POSSIBLY LIFR IN HEAVY RAIN. WINDS WILL GENERALLY BE LIGHT THIS AFTERNOON AND THIS EVENING. LATEST MODELS TAKE REMNANTS OF BONNIE TO THE EAST OF ORIGINAL TRACK. HEAVY PRECIP WILL BE EAST OF TAF ROUTE KGFL-KALB-KPOU. BY TONIGHT...THERE COULD BE SOME MIST/FOG WITH ANY LEFTOVER MOISTURE CAUSING VISIBILITIES TO BE REDUCED TO LESS THAN 3 MILES. HYDROLOGY... FLOOD WATCH IN EFFECT THROUGH THIS AFTERNOON. FLOOD WARNING FOR METTAWEE RIVER AT MIDDLE GRANVILLE IN WASHINGTON COUNTY FOR MINOR FLOODING. HEAVIEST RAINFALL EXPECTED TO SHIFT INTO NEW ENGLAND BUT STILL NEED TO DEAL WITH RUNOFF FROM PAST 24 HOURS AMOUNTS. QPF FOR 700 AM FRIDAY THROUGH 7AM SATURDAY RANGES FROM 0.25 INCH WEST TO AROUND 1.00 INCH EAST. && $$ SHORT TERM (UPDATE)...WASULA ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 958 PM EDT FRI AUG 13 2004 .SHORT TERM UPDATE (TONIGHT) STILL A GOOD DEAL OF SC/AC ACRS FCST AREA THIS EVNG...BUT CLOUDS ARE CONTINUING TO THIN. HAVE SEEN A FEW RENEGADE -SHRA UP NEAR KFWA...AND MAY BE GETTING A SPRINKLE OR TWO ACRS WEST CNTRL OH. HOWEVER...RADAR RETURNS ARE DECREASING AND LARGE AREA OF NVA NOTED ON RUC 500 MB PROG MOVNG IN FROM WEST...SO NOT EXPECTING ANY PCPN REST OF NIGHT. CURRENT RUC DATA ALSO INDCG GOOD AMOUNT OF MOISTURE TO HANG ON AT 700/850 MB LVLS FOR MUCH OF NIGHT. WHILE CLOUDS SHOULD CONTINUE TO THIN AND DECREASE IN COVERAGE AS NIGHT PROGRESSES...AM NOT AS CONFIDENT THAT WE WILL COMPLETELY CLEAR OUT ACRS FCST AREA. HAVE ADJUSTED TO SKIES BECMG PTLY CLDY OVERNIGHT AS A RESULT. STILL THINKING THERE WILL BE ENUF BREAKS IN THE CLOUDS FOR SOME PATCHY FOG TOWARDS DAWN. ONLY OTHER CHANGE WAS TO BUMP OVERNIGHT LOWS UP A DEGREE OR TWO WITH MORE CLOUDS EXPECTED. UPDATE ALREADY OUT. && .AVIATION (00Z-00Z) EXTENSIVE CU/AC DECK SLOWLY ERODING THIS EVNG...AS WEAK S/WV HAS SHIFTED EAST OF REGION. CU FIELD APPEARS TO BE BREAKING UP FURTHER WEST...WITH LARGE AREA OF NVA NOTED ACRS INDIANA/ILLINOIS. HAVE SEEN A FEW RETURNS ON RADAR...BUT CLOSEST OBS SITE TO REPORT ANY PCPN IS AT KDFI (DEFIANCE) IN NW OHIO. HAVE BACKED OFF A BIT ON CLEARING TREND FROM 18Z TAFS...AS THINK IT WILL TAKE MUCH OF EVNG FOR CLOUDS TO DISSIPATE. BRING IN SKC AT ALL BUT KCMH AFT MIDNITE... BUT EVEN HERE SHOULD JUST BE SCT CU/AC OVERNIGHT. WITH DEWPTS HAVING RECOVERED INTO L/M50S ACRS MUCH OF SRN/WRN OHIO...THINK THERE WILL BE SOME FOG DVPLMNT TOWARDS DAWN. HIT FOG HARDEST AT KCVG/KLUK WHERE DEWPTS ARE HIGHEST. EXPECT MVFR CONDITIONS AT KCVG/KDAY/KILN/ KCMH WITH IFR VSBYS EXPECTED AT KLUK. AFTER NICE START TO MRNG...SHOULD CU UP ONCE AGAIN WITH UPR TROF HOLDING JUST TO OUR WEST. ONCE AGAIN AFTN MODEL RUNS TRYING TO SPIT OUT SOME LIGHT QPF ACRS NRN OHIO SAT AFTN. WITH LITTLE IF ANY ISENT LIFT NOTED EXPECT DRY CONDITIONS AT ALL TAF SITES. CU WILL GO BKN DURING AFTN HOURS...BUT DO THINK WE WILL SEE MORE SUN THAN WE DID TODAY. && .SHORT TERM (TONIGHT THROUGH SUNDAY NIGHT)... H5 TROF REMAINS LOCKED OVER THE GREAT LAKES WAITING FOR BONNIE AND CHARLEY TO CLEAR THE EAST COAST. MUCH OF THE CU WEST OF CENTRAL INDIANA APPEARS CONVECTIVE AND EXPECT IT TO DRY QUICKLY AFTER SUNSET. THEREFORE WILL GO WITH A FORECAST OF CLEARING SKIES. SKIES WILL CU AGAIN TOMORROW. MODELS ARE NOW FORECASTING ANOTHER H5 SHORTWAVE TO DROP INTO THE TROF SAT INTO SUNDAY. THIS WAVE SWINGS ACROSS THE FA ON SUN...SO WILL GO WHICH LOW CHANCE POPS ON SUNDAY. WENT BELOW GUIDANCE FOR HIGHS SAT AND SUNDAY. && .LONG TERM (MONDAY THROUGH FRIDAY)... MODELS ARE CONSISTENT WITH PREVIOUS RUNS SO THERE WILL BE LITTLE CHANGE TO THE EXTENDED. DRY WEATHER IS STILL EXPECTED EARLY NEXT WEEK. WILL CONTINUE TO CARRY CHANCE TSRA WEDNESDAY AND THURSDAY WITH APPROACH AND PASSAGE OF A COLD FRONT. WILL LINGER SLIGHT CHANCE INTO FRIDAY MORNING BEHIND THE FRONT. AREA WILL BE UNDER A WARMER SOUTHWEST FLOW FOR MOST OF THE PERIOD SO TEMPERATURES WILL APPROACH CLIMATOLOGICAL AVERAGES. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. IN...NONE. KY...NONE. && $$ UPDATE/AVIATION: RYAN SHORT TERM: SITES LONG TERM: CONIGLIO oh AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1017 AM EDT FRI AUG 13 2004 .SHORT TERM (REST OF TODAY)... UPPER LEVEL TROUGH JUST UPSTREAM WILL STEAR SHORTWAVE ENERGY FROM SW TO NE. SURFACE FRONT LOCATED ACROSS E PORTION OF AREA PROGGED TO MOVE JUST A LITTLE TO E TODAY BEFORE HALTING. SUFFIENT MOISTURE EXISTS VICINITY OF THIS BOUNDARY TO CONTINUE CHANCE POPS E...WHILE ENOUGH MOISTURE BEHIND BOUNDAY FOR DIFFERENTIAL HEATING TO PRODUCE ISOLATED CONVECTION MOUNTAINS/BLUE RIDGE...THOUGH INSTABILITY RATHER LIMITED. ADJUSTED SKY COVER PER SATELLITE IMAGERY...PORTRAYING BREAKS IMMEDIATE LEE OF MOUNTAINS. ALTHOUGH OVERNIGHT MAV GUIDANCE QUITE COOL...EXPECT RADIATIONAL HEATING IN BREAKS OR THIN CIRRUS TO ALLOW AREA TO REACH FORECAST MAXIMUMS. MADE MINOR TWEAKS TO DEW POINTS BASED ON MESOETA. UPDATED WIND WITH RUC...WHICH SEEMED TO HAVE GOOD HANDLE ON DIRECTION...BUT BOOSTED SPEED A BIT BASED ON BUFKIT SOUNDINGS. WILL UPDATE TABULAR PRODUCTS TO CAPTURE TRENDS... AND ZONES FOR AFTERNOON WORDING. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 425 AM EDT FRI AUG 13 2004 SHORT TERM (TODAY THROUGH SUNDAY)... REMNANTS OF BONNIE PULLING AWAY FROM THE CWFA ATTM AND WILL HAVE LITTLE IF ANY ADDITIONAL EFFECT ON OUR WX. SOME LINGERING SHRA THIS MORNING BUT WILL REMAIN ISOLATED AND LIGHT. GOOD LOW LEVEL MOISTURE REMAINS OVER THE AREA TODAY. SFC FNT OVER THE AREA WILL PROVIDE A LITTLE SFC CONVERGENCE...SO HAVE CHC POP IN THE AFTERNOON EAST AND SLIGHT CHC POP WEST. OBVIOUSLY...BIGGEST CONCERN THIS FCST PACKAGE IS TRACK OF HURRICANE CHARLEY. LATEST FCST GUIDANCE TAKES CENTER EAST OF OUR CWFA...WITH AXIS OF HEAVY RAINFALL TO OUR EAST. GFS CLOSEST TO CURRENT FCST TRACK SO HAVE FOLLOWED THAT AND GUIDANCE FROM NATIONAL CENTERS. HAVE GONE WITH THE HIGHER MAV POPS...BUT STILL TRIED TO INDICATE A GRADIENT TO LOWER POP IN THE WEST. ALL THE GUIDANCE INDICATES HEAVIEST RAIN WILL BE ALONG THE I-77 CORRIDOR STARTING SATURDAY MORNING CONTINUING THRU THE DAY. HOWEVER ANY SLIGHT DEVIATION IN THE TRACK COULD CAUSE A MAJOR CHANGE IN THE TRACK AND TIMING OF THE HEAVY RAINFALL. THEREFORE HAVE DECIDED TO HOLD OFF ON ANY WATCHES ATTM. EXPECT THE DAY SHIFT TO HAVE A BETTER IDEA AND CAN FINE TUNE THE WATCH TO INCLUDE THE AREAS WITH THE GREATEST THREAT. HAVE UPDATED ESF TO ADDRESS THIS THINKING. WILL ISSUE AN SPS AFTER THE 5 AM HURRICANE FCST UPDATE TO ADDRESS WIND CONCERNS. ALL THAT SAID...POP INCREASING TO LIKELY AFTER MIDNIGHT AND CATEGORICAL SATURDAY ACROSS MUCH OF THE AREA. HAVE RAMPED UP QPF FCST IN THE EAST AS WELL. POP DROPPING OFF TO CHC SATURDAY NIGHT AND SLIGHT CHC SUNDAY. WENT TOWARD THE WARMER GUIDANCE ON LOWS AND IN BETWEEN ON HIGHS...XCPT SUNDAY HIGHS WHERE WARMER GUIDANCE FOLLOWED. LONG TERM (SUNDAY NIGHT THROUGH THURSDAY)... NO CHANGES TO GOING FCST THESE PERIODS. AVIATION... A WIDE RANGE OF CEILINGS AND VSBY ACROSS THE CWFA THIS MORNING... WITH THE MOST DIRE CONDITIONS NOTED IN THE DEEP MOISTURE AND UPGLIDE REGIME ACROSS THE EASTERN PIEDMONT. SCATTERED SHOWERS CONTINUE TO DEVELOP ALONG THE FRONT FROM THE NORTHERN PART OF THE UPSTATE INTO THE NC FOOTHILLS...AND WILL HANDLE THIS ACTIVITY WITH VCSH AT THE 3 PIEDMONT SITES...UNTIL UPPER JET AXIS SHUNTS THE DEEPER MOISTURE TO THE EAST LATER THIS MORNING. AS DRIER MID AND UPPER LEVEL AIR CONTINUES TO WORK ITS WAY INTO THE REGION...WE MAY SEE CEILINGS AND VSBYS LOWER TOWARD SUNRISE...AND HAVE GENERALLY INDICATED THIS IN THE TAFS...ESP AT KGSP AND KAND. AT KAVL...SURFACE FLOW CHANNELING DOWN THE FRENCH BROAD VALLEY AT 10-15 KTS SHOULD PREVENT IFR VSBY FROM FORMING...BUT CONSIDERING THE PLENTIFUL LOW LEVEL MOISTURE... HAVE CARRIED TEMPOS FOR MVFR VSBY WITH AN IFR CEILING DURING THE PRE-DAWN. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SHORT TERM (UPDATE)...JAT sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MEMPHIS TN 957 AM CDT FRI AUG 13 2004 A DEEP UPPER LEVEL TROUGH REMAINS ENTRENCHED OVER THE EASTERN HALF OF THE UNITED STATES...WITH UNSEASONABLY LOW HEIGHTS. AT THE SURFACE... HIGH PRESSURE CONTINUES TO BUILD SOUTHEAST INTO THE FORECAST AREA. THESE WEATHER FEATURES WERE RESPONSIBLE FOR LAST NIGHTS RECORD COLD TEMPERATURES. THE UNSEASONABLY COOL AIRMASS WILL REMAIN IN PLACE ACROSS THE AREA TODAY WITH CONTINUED LOW LEVEL COLD AIR ADVECTION NOTED FROM THE 850 MB UPPER AIR PLOTS THIS MORNING. 12Z RUC MODEL INDICATES CONTINUED COLD ADVECTION THROUGH THE DAY...SO CURRENT FORECAST HIGH TEMPS LOOK GOOD. MORNING 12Z SOUNDING FROM NASHVILLE SHOWING A SHALLOW LAYER OF MOISTURE AROUND 800 MB AND REGIONAL FORECAST SOUNDINGS KEEPING A SHALLOW LAYER OF LOW LEVEL MOISTURE IN PLACE THIS AFTERNOON. WITH UNSEASONABLY COLD AIR ALOFT...THE SHALLOW MOISTURE IN PLACE...AND SOME DAYTIME HEATING...EXPECT SHALLOW CU FIELD TO ONCE AGAIN DEVELOP THIS AFTERNOON ACROSS THE FORECAST AREA WITH THE GREATEST COVERAGE OVER EASTERN AREAS. SO PARTLY CLOUDY WORDING IN CURRENT ZONES WILL SUFFICE. DRY WEATHER WILL ALSO CONTINUE TODAY WITH HIGH PRESSURE IN CONTROL. IN ADDITION...GRADIENT REMAINS A BIT TIGHTER ACROSS EASTERN AREAS SO HIGHER WINDS EASTERN SECTIONS AS GOING IN CURRENT FORECAST LOOKS GOOD AS WELL. CURRENT FORECAST LOOKS ON TRACK THIS MORNING...SO NO UPDATES WILL BE NEEDED. && .PREVIOUS DISCUSSION FROM 317 AM... DEEP UPPER TROF OVER THE EASTERN U.S. USHERING UNSEASONABLY COOL AIR INTO THE MID SOUTH. UNION CITY...PARIS AND SAVANNAH ALL AT 48 DEGREES WITH OVER 3 HOURS UNTIL SUNRISE! TUP HAS ALREADY BROKEN A RECORD OF 57...CURRENT TEMPS IS 55. MKL WAS DOWN TO 52 AND SHOULD BE ABLE TO TIE OR BREAK THE RECORD OF 50. EXPECT ANOTHER COOL DAY AS LOW LEVEL CAA CONTINUES TODAY. 850 MB TEMPS OF 8-10C AND 1000-500MB THICKNESSES OF 5580-5610M TODAY WHICH ARE RARE FOR MID AUGUST. HIGHS IN THE MID 70S THIS AFTN WILL BE ABOUT 15 DEGREES BELOW NORMAL. ALL 4 MAJOR CLIMATE SITES...MEM...MKL...TUP...JBR...ARE EXPECTED TO BREAK COOLEST HIGH TEMP RECORDS THIS AFTN. WL SEE SOME SCT CU THIS AFTN BUT STILL PLENTY OF SUNSHINE. ANOTHER COOL ONE TONIGHT. CLEAR SKIES...DRY AIRMASS AND SFC WINDS DECOUPLING WILL ONCE AGAIN LEAD TO TEMPS DROPPING WELL INTO THE 50S EVERYWHERE. PROBABLY WILL BE SOME UPPER 40S IN THE COOLER LOCALES. ALL 4 MAJOR CLIMATE SITES ARE EXPECTED TO BREAK THERE RESPECTIVE RECORD LOWS. AIRMASS WL BEGIN A SLOW MODERATING TREND OVER THE WEEKEND AS UPPER TROF BEINGS TO LIFT NORTHEAST AND WEAKEN. SURFACE HIGH PRESSURE WILL CONT TO DOMINATE THE MS VALLEY THROUGH THE WEEKEND. EXPECT HIGHS TO BE NEAR 80 ON SAT AFTN AND IN THE LOWER 80S SUN AFTN. AIRMASS WL STILL BE QUITE DRY WITH DEWPOINTS IN THE 50S SO STILL QUITE PLEASANT WITH PLENTY OF SUNSHINE. COOL NIGHTS WILL CONT THROUGH THE WEEKEND. UPPER PATTERN BECOMES MORE ZONAL EARLY NEXT WEEK WITH SURFACE RIDGE SLIDING SOUTHEAST OF THE REGION BY LATE TUE. THIS WL CONTINUE THE MODERATING TREND AS TEMPS CLIMB INTO THE UPPER 80S BY WED WITH INCREASING HUMIDITY. NEXT CHANCE OF RAIN WL BE THU AS ANOTHER FRONT PUSHES THROUGH THE REGION. && .MEG...WATCHES/WARNINGS/ADVISORIES... AR...NONE. MS...NONE. MO...NONE. TN...NONE. && $$ JLH/SJM tn AREA FORECAST DISCUSSION...UPDATED FOR AVIATION NATIONAL WEATHER SERVICE FORT WORTH TX 1230 PM CDT FRI AUG 13 2004 .DISCUSSION... OTHER THAT ISOLATED SHOWERS...CIGS WILL BE VFR...WITH UNLIMITED VISIBILITIES. 59 && .UPDATE... 1045 AM CDT SOME MID CLOUDS WILL LINGER INTO THE EARLY AFTERNOON...BUT MOST LOCATIONS WILL BE GENERALLY PARTLY CLOUDY THE REMAINDER OF THE DAY. WILL UPDATE TO FRESHEN UP TEMPORAL WORDING...KEEPING AFTERNOON POPS WESTERN ZONES. 25 && .AVIATION... 610 AM CDT MID AND HIGH CLOUDS WILL CONTINUE TO SPREAD ACROSS THE AREA AIRPORTS TODAY AS NORTHWESTERLY FLOW ALOFT PREVAILS. SCATTERED SHOWERS ACROSS SOUTHERN OKLAHOMA...ARE EXPECTED TO REMAIN TO THE NORTHEAST OF THE METROPLEX AIRPORTS THIS MORNING. ISOLATED THUNDERSTORMS ARE EXPECTED ACROSS THE WEST LATE THIS AFTERNOON INTO THE EVENING...BUT THIS ACTIVITY IS EXPECTED TO REMAIN WEST OF THE METROPLEX AIRPORTS. THUS WILL KEEP VFR CEILINGS IN FOR MOST OF TODAY...WITH LIGHT NORTH TO NORTHEAST WINDS...BECOMING SOUTHEAST AT UNDER 10 KNOTS. #58 && .UPDATE... 410 AM CDT SOME SHOWERS POPPING UP IN SOUTHERN OKLAHOMA MOVING SOUTHEAST. WILL UPDATE NORTHERN TWO ROWS OF COUNTIES FOR POPS THIS MORNING. CONVECTION IS ELEVATED AND GOT FIRED UP BY WEAK SOUTHEAST MOVING VORTICITY MAX MAX NOW ANALYZED IN NEW RUC DATA. CONVECTION SHOULD WEAKEN AFTER SUNRISE. 84 && .PREV DISCUSSION... 300 AM CDT HERE WE GO AGAIN...RIDING THE MODEL SEESAW. YESTERDAY THINGS LOOKED FAIRLY DRY...BUT WITH NORTHWEST FLOW ALOFT ALL BETS ARE OFF. SOUTHERLY SURFACE FLOW COMES BACK SATURDAY WITH SLOW DEWPOINT INCREASE THROUGH SUNDAY WHEN DEWPOINTS ARE BACK IN THE MID 60S. CONVECTION HAS BEEN RIDING DOWN THE UPPER FLOW FROM THE HIGH PLAINS EVERY EVENING...AND WITH THE DEWPOINTS RISING OUR INSTABILITY WILL INCREASE. MODEL PRECIP GUIDANCE IS ALL OVER THE PLACE...SO WHAT I HAVE TRIED TO DO OVER THE NEXT FEW DAYS IS INDICATE LOWER CONFIDENCE POPS WHERE THERE IS SOME MODEL CONSENSUS...AND POPS WILL HAVE TO BE ADJUSTED AS TIME PROGRESSES...I HAVE NO DOUBT ABOUT THAT. FRIDAY...LOW POPS INDICATED WESTERN HALF WHERE SOUTHEAST FLOW BEGINS TO RETURN PROVIDING SOME SURFACE MOISTURE CONVERGENCE AND WEAK UPSLOPE. THEN OVERNIGHT LOOKS LIKE MCS MAY MOVE INTO NORTHWEST ZONES EARLY WITH REMNANTS POSSIBLY MAKING IT AS FAR AS THE METROPLEX AND SOUTHWEST EARLY SATURDAY MORNING. SATURDAY...AFTER NOCTURNAL PRECIP DIES OUT...NEW DEVELOPMENT SHOWS UP. GFS KEEPS PRECIP TO OUR NORTHWEST. ETA...NGM...MESOETA BRING A 60 DEGREE DEWPOINT AXIS OVER CWA AND DEVELOP STORMS ALONG IT. CROSS SECTION ANALYSIS SHOWS BEHAVIOR LIKE A WEAK WARM FRONT WITH LIFT BEGINNING AROUND COLLEGE STATION AND SLOPING UP OVER NORTHWEST OF WICHITA FALLS. MOISTURE CONVERGENCE INDICATED IN THIS ZONE WITH INSTABILITY ABOVE. THE POPS I PUT IN RUN GENERALLY WEST OF I 35 AND NORTH OF I 20...INCLUDING THE METROPLEX. SUNDAY...BEST AREA LOOKS NORTH OF METROPLEX UP INTO OKLAHOMA WHERE MOISTURE AXIS WILL BE LOCATED. UPPER DISTURBANCE MOVES ACROSS OKLAHOMA TO PROVIDE FOCUS FOR STORMS. THE POPS EXTEND FROM YOUNG...DENTON..HOPKINS COUNTIES AND NORTH. MONDAY THROUGH WEDNESDAY...FLOW ALOFT BECOMES MORE WESTERLY AND BY WEDNESDAY AFTERNOON MODERATE SHORT WAVE MOVES ACROSS WEST TEXAS TOWARDS US. MONDAY AND TUESDAY LOOK DRY AND I INDICATED POPS NORTHWEST FOR WEDNESDAY AFTERNOON AND EVENING. THURSDAY AND FRIDAY...NORTHWEST FLOW SETS UP AGAIN AND GFS LONG RANGE BRINGS DISTURBANCE ACROSS NORTHERN HALF THURSDAY...AND THEN SHOWS WIDESPREAD POPS THURSDAY EVENING INTO FRIDAY. I HAVE INDICATED THIS WITH POPS NORTHERN HALF OF CWA THURSDAY AND THEN ALL OF CWA THURSDAY NIGHT THROUGH FRIDAY. 84 && PRELIMINARY POINT TEMPS/POPS DALLAS-FT. WORTH, TX 89 66 90 68 / 0 20 20 0 WACO, TX 89 63 90 67 / 0 0 0 0 PARIS, TX 85 62 89 65 / 0 0 0 0 DENTON, TX 86 63 90 67 / 0 20 20 0 MCKINNEY, TX 87 63 90 67 / 0 20 20 0 DALLAS, TX 89 66 90 68 / 0 20 20 0 TERRELL, TX 88 64 90 67 / 0 0 0 0 CORSICANA, TX 89 63 90 67 / 0 0 0 0 TEMPLE, TX 89 63 90 67 / 20 0 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1045 AM CDT FRI AUG 13 2004 .UPDATE... 1045 AM CDT SOME MID CLOUDS WILL LINGER INTO THE EARLY AFTERNOON...BUT MOST LOCATIONS WILL BE GENERALLY PARTLY CLOUDY THE REMAINDER OF THE DAY. WILL UPDATE TO FRESHEN UP TEMPORAL WORDING...KEEPING AFTERNOON POPS WESTERN ZONES. 25 && .AVIATION... 610 AM CDT MID AND HIGH CLOUDS WILL CONTINUE TO SPREAD ACROSS THE AREA AIRPORTS TODAY AS NORTHWESTERLY FLOW ALOFT PREVAILS. SCATTERED SHOWERS ACROSS SOUTHERN OKLAHOMA...ARE EXPECTED TO REMAIN TO THE NORTHEAST OF THE METROPLEX AIRPORTS THIS MORNING. ISOLATED THUNDERSTORMS ARE EXPECTED ACROSS THE WEST LATE THIS AFTERNOON INTO THE EVENING...BUT THIS ACTIVITY IS EXPECTED TO REMAIN WEST OF THE METROPLEX AIRPORTS. THUS WILL KEEP VFR CEILINGS IN FOR MOST OF TODAY...WITH LIGHT NORTH TO NORTHEAST WINDS...BECOMING SOUTHEAST AT UNDER 10 KNOTS. #58 && .UPDATE... 410 AM CDT SOME SHOWERS POPPING UP IN SOUTHERN OKLAHOMA MOVING SOUTHEAST. WILL UPDATE NORTHERN TWO ROWS OF COUNTIES FOR POPS THIS MORNING. CONVECTION IS ELEVATED AND GOT FIRED UP BY WEAK SOUTHEAST MOVING VORTICITY MAX MAX NOW ANALYZED IN NEW RUC DATA. CONVECTION SHOULD WEAKEN AFTER SUNRISE. 84 && .PREV DISCUSSION... 300 AM CDT HERE WE GO AGAIN...RIDING THE MODEL SEESAW. YESTERDAY THINGS LOOKED FAIRLY DRY...BUT WITH NORTHWEST FLOW ALOFT ALL BETS ARE OFF. SOUTHERLY SURFACE FLOW COMES BACK SATURDAY WITH SLOW DEWPOINT INCREASE THROUGH SUNDAY WHEN DEWPOINTS ARE BACK IN THE MID 60S. CONVECTION HAS BEEN RIDING DOWN THE UPPER FLOW FROM THE HIGH PLAINS EVERY EVENING...AND WITH THE DEWPOINTS RISING OUR INSTABILITY WILL INCREASE. MODEL PRECIP GUIDANCE IS ALL OVER THE PLACE...SO WHAT I HAVE TRIED TO DO OVER THE NEXT FEW DAYS IS INDICATE LOWER CONFIDENCE POPS WHERE THERE IS SOME MODEL CONSENSUS...AND POPS WILL HAVE TO BE ADJUSTED AS TIME PROGRESSES...I HAVE NO DOUBT ABOUT THAT. FRIDAY...LOW POPS INDICATED WESTERN HALF WHERE SOUTHEAST FLOW BEGINS TO RETURN PROVIDING SOME SURFACE MOISTURE CONVERGENCE AND WEAK UPSLOPE. THEN OVERNIGHT LOOKS LIKE MCS MAY MOVE INTO NORTHWEST ZONES EARLY WITH REMNANTS POSSIBLY MAKING IT AS FAR AS THE METROPLEX AND SOUTHWEST EARLY SATURDAY MORNING. SATURDAY...AFTER NOCTURNAL PRECIP DIES OUT...NEW DEVELOPMENT SHOWS UP. GFS KEEPS PRECIP TO OUR NORTHWEST. ETA...NGM...MESOETA BRING A 60 DEGREE DEWPOINT AXIS OVER CWA AND DEVELOP STORMS ALONG IT. CROSS SECTION ANALYSIS SHOWS BEHAVIOR LIKE A WEAK WARM FRONT WITH LIFT BEGINNING AROUND COLLEGE STATION AND SLOPING UP OVER NORTHWEST OF WICHITA FALLS. MOISTURE CONVERGENCE INDICATED IN THIS ZONE WITH INSTABILITY ABOVE. THE POPS I PUT IN RUN GENERALLY WEST OF I 35 AND NORTH OF I 20...INCLUDING THE METROPLEX. SUNDAY...BEST AREA LOOKS NORTH OF METROPLEX UP INTO OKLAHOMA WHERE MOISTURE AXIS WILL BE LOCATED. UPPER DISTURBANCE MOVES ACROSS OKLAHOMA TO PROVIDE FOCUS FOR STORMS. THE POPS EXTEND FROM YOUNG...DENTON..HOPKINS COUNTIES AND NORTH. MONDAY THROUGH WEDNESDAY...FLOW ALOFT BECOMES MORE WESTERLY AND BY WEDNESDAY AFTERNOON MODERATE SHORT WAVE MOVES ACROSS WEST TEXAS TOWARDS US. MONDAY AND TUESDAY LOOK DRY AND I INDICATED POPS NORTHWEST FOR WEDNESDAY AFTERNOON AND EVENING. THURSDAY AND FRIDAY...NORTHWEST FLOW SETS UP AGAIN AND GFS LONG RANGE BRINGS DISTURBANCE ACROSS NORTHERN HALF THURSDAY...AND THEN SHOWS WIDESPREAD POPS THURSDAY EVENING INTO FRIDAY. I HAVE INDICATED THIS WITH POPS NORTHERN HALF OF CWA THURSDAY AND THEN ALL OF CWA THURSDAY NIGHT THROUGH FRIDAY. 84 && PRELIMINARY POINT TEMPS/POPS DALLAS-FT. WORTH, TX 89 66 90 68 / 0 20 20 0 WACO, TX 89 63 90 67 / 0 0 0 0 PARIS, TX 85 62 89 65 / 0 0 0 0 DENTON, TX 86 63 90 67 / 0 20 20 0 MCKINNEY, TX 87 63 90 67 / 0 20 20 0 DALLAS, TX 89 66 90 68 / 0 20 20 0 TERRELL, TX 88 64 90 67 / 0 0 0 0 CORSICANA, TX 89 63 90 67 / 0 0 0 0 TEMPLE, TX 89 63 90 67 / 20 0 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 610 AM CDT FRI AUG 13 2004 .AVIATION... MID AND HIGH CLOUDS WILL CONTINUE TO SPREAD ACROSS THE AREA AIRPORTS TODAY AS NORTHWESTERLY FLOW ALOFT PREVAILS. SCATTERED SHOWERS ACROSS SOUTHERN OKLAHOMA...ARE EXPECTED TO REMAIN TO THE NORTHEAST OF THE METROPLEX AIRPORTS THIS MORNING. ISOLATED THUNDERTORMS ARE EXPECTED ACROSS THE WEST LATE THIS AFTERNOON INTO THE EVENING...BUT THIS ACTIVITY IS EXPECTED TO REMAIN WEST OF THE METROPLEX AIRPORTS. THUS WILL KEEP VFR CEILINGS IN FOR MOST OF TODAY...WITH LIGHT NORTH TO NORTHEAST WINDS...BECOMING SOUTHEAST AT UNDER 10 KNOTS. #58 && .UPDATE... 410 AM CDT FRI AUG 13 2004 SOME SHOWERS POPPING UP IN SOUTHERN OKLAHOMA MOVING SOUTHEAST. WILL UPDATE NORTHERN TWO ROWS OF COUNTIES FOR POPS THIS MORNING. CONVECTION IS ELEVATED AND GOT FIRED UP BY WEAK SOUTHEAST MOVING VORTICITY MAX MAX NOW ANALYZED IN NEW RUC DATA. CONVECTION SHOULD WEAKEN AFTER SUNRISE. 84 && .PREV DISCUSSION... 300 AM CDT FRI AUG 13 2004 HERE WE GO AGAIN...RIDING THE MODEL SEESAW. YESTERDAY THINGS LOOKED FAIRLY DRY...BUT WITH NORTHWEST FLOW ALOFT ALL BETS ARE OFF. SOUTHERLY SURFACE FLOW COMES BACK SATURDAY WITH SLOW DEWPOINT INCREASE THROUGH SUNDAY WHEN DEWPOINTS ARE BACK IN THE MID 60S. CONVECTION HAS BEEN RIDING DOWN THE UPPER FLOW FROM THE HIGH PLAINS EVERY EVENING...AND WITH THE DEWPOINTS RISING OUR INSTABILITY WILL INCREASE. MODEL PRECIP GUIDANCE IS ALL OVER THE PLACE...SO WHAT I HAVE TRIED TO DO OVER THE NEXT FEW DAYS IS INDICATE LOWER CONFIDENCE POPS WHERE THERE IS SOME MODEL CONSENSUS...AND POPS WILL HAVE TO BE ADJUSTED AS TIME PROGRESSES...I HAVE NO DOUBT ABOUT THAT. FRIDAY...LOW POPS INDICATED WESTERN HALF WHERE SOUTHEAST FLOW BEGINS TO RETURN PROVIDING SOME SURFACE MOISTURE CONVERGENCE AND WEAK UPSLOPE. THEN OVERNIGHT LOOKS LIKE MCS MAY MOVE INTO NORTHWEST ZONES EARLY WITH REMNANTS POSSIBLY MAKING IT AS FAR AS THE METROPLEX AND SOUTHWEST EARLY SATURDAY MORNING. SATURDAY...AFTER NOCTURNAL PRECIP DIES OUT...NEW DEVELOPMENT SHOWS UP. GFS KEEPS PRECIP TO OUR NORTHWEST. ETA...NGM...MESOETA BRING A 60 DEGREE DEWPOINT AXIS OVER CWA AND DEVELOP STORMS ALONG IT. CROSS SECTION ANALYSIS SHOWS BEHAVIOR LIKE A WEAK WARM FRONT WITH LIFT BEGINNING AROUND COLLEGE STATION AND SLOPING UP OVER NORTHWEST OF WICHITA FALLS. MOISTURE CONVERGENCE INDICATED IN THIS ZONE WITH INSTABILITY ABOVE. THE POPS I PUT IN RUN GENERALLY WEST OF I 35 AND NORTH OF I 20...INCLUDING THE METROPLEX. SUNDAY...BEST AREA LOOKS NORTH OF METROPLEX UP INTO OKLAHOMA WHERE MOISTURE AXIS WILL BE LOCATED. UPPER DISTURBANCE MOVES ACROSS OKLAHOMA TO PROVIDE FOCUS FOR STORMS. THE POPS EXTEND FROM YOUNG...DENTON..HOPKINS COUNTIES AND NORTH. MONDAY THROUGH WEDNESDAY...FLOW ALOFT BECOMES MORE WESTERLY AND BY WEDNESDAY AFTERNOON MODERATE SHORT WAVE MOVES ACROSS WEST TEXAS TOWARDS US. MONDAY AND TUESDAY LOOK DRY AND I INDICATED POPS NORTHWEST FOR WEDNESDAY AFTERNOON AND EVENING. THURSDAY AND FRIDAY...NORTHWEST FLOW SETS UP AGAIN AND GFS LONG RANGE BRINGS DISTURBANCE ACROSS NORTHERN HALF THURSDAY...AND THEN SHOWS WIDESPREAD POPS THURSDAY EVENING INTO FRIDAY. I HAVE INDICATED THIS WITH POPS NORTHERN HALF OF CWA THURSDAY AND THEN ALL OF CWA THURSDAY NIGHT THROUGH FRIDAY. 84 && PRELIMINARY POINT TEMPS/POPS DALLAS-FT. WORTH, TX 89 66 90 68 / 0 20 20 0 WACO, TX 89 63 90 67 / 0 0 0 0 PARIS, TX 85 62 89 65 / 0 0 0 0 DENTON, TX 86 63 90 67 / 0 20 20 0 MCKINNEY, TX 87 63 90 67 / 0 20 20 0 DALLAS, TX 89 66 90 68 / 0 20 20 0 TERRELL, TX 88 64 90 67 / 0 0 0 0 CORSICANA, TX 89 63 90 67 / 0 0 0 0 TEMPLE, TX 89 63 90 67 / 20 0 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 432 AM CDT SAT AUG 14 2004 .DISCUSSION... UPDATING/CORRECTING GRIDS TO RELECT DVLPG SHRA IN CNTRL KS AND TO FIX WIND GUST GRIDS ON MON. FAIRLY DECENT SLUG OF MSTR SLIDING SE OUT OF NEB. LTST RUC IS NOT TOO BAD, SUG PCPN WL PROBABLY HOLD TOGETHER FOR A FEW MORE HRS, BUT SHUD STRUGGLE TO SPREAD MUCH FURTHER S/E THAN GBD-MCPHERSON LN. UPDATED ZFP OUT...GRIDS POSTING NOW. .PREVIOUS DISCUSSION... 339 AM CDT SAT AUG 14 2004 TDA: WEAK ECHOES EVIDENT AGN THIS MORNING IN SE KS AND JUST TO W OF FCST AREA. HAVE INCLD SML POPS IN FAR SW WHERE PCPN IS MORE THAT A FEW SPKLS. OTHERWISE TEMPS SHUD NOT BE MUCH DIFFERENT THAN YDA. TNGT-SUN: WL KEEP CHC OF POPS GOING TNGT IN FAR W WITH TEMP/MSTR ADVCTN IN BAROCLINIC ZONE. OUTSIDE CHC THAT PCPN COULD DVLP ERY THIS EVE, BUT ANTICIPATE THE BEST CHC TOWARDS DAYBRK SUN. ALSO PSBL THAT PCPN COULD LINGER PAST 12Z, BUT WL KEEP FCST DRY FOR NOW. LINGERING CLDS ON SUN SHUD CUT INTO POTENTIAL WARMUP...WITH LTL CHG TO GOING FCST. SUN NGT-MON: MODELS STARTING TO COME AROUND WITH A BTR CHC OF PCPN SUN NGT. AGN IT MAY BE PSBL TO BREAK CAP IN THE FAR W SUN EVE...BUT BETTER CHC OVR ENTIRE AREA IS IN CLIMO FAVORED ERY MORNING HRS. ETA HINTS THAT REMNANT OF TSTMS/MCS OVR NEB COULD BE THE PRIMARY CULPRIT FOR THE ERY MORNING PCPN...AND GIVEN TEMP/DEWPT GRADIENTS AND WK SHRTWV... CERTAINTLY CANNOT BE RULED OUT. WHATEVER THE MECHANISM, BOTH ETA/GFS MOS HAVE COME IN WITH CHC POPS, AND THAT SEEMS REASONABLE. TEMPS REBOUND IN WAKE OF SYS ACR THE W, WHILE LINGERING CLDS SHUD CUT INTO MAXES IN FAR SE. TUE-FRI: MODELS STILL OSCILLATING ON TIMING OF CFNT, WITH YDA 12Z RUNS A BIT SLOWER AND LOOKING AT 00Z GFS IS APPARENTLY SLOWER YET. HOWEVER 12Z ENSEMBLES DID SHOW SOME OUTLIERS THAT WOULD RESULT IN MUCH DIFFERENT OUTCOMES. THE 12Z ECMWF IS SOMEWHAT SUSPICIOUS GIVEN THE WAY IT DEEPENS CANADIAN LOW AND SHUNTS COOLER AIR E. THIS IS QUITE A BIT DIFFERENT FM PREV RUN (AND RECENT HISTORY WHERE COOLER AIR HAS EASILY SPILLED INTO THE REGION.) THE LACK OF COLD SURGE LEAVES A WK SFC BNDRY HUNG UP W/E ACRS FCST AREA FOR MOST OF THIS PD...WHICH IS NOT TOO DISSIMILAR FM LTST GFS. UNFORTUNATELY WL NOT GET 00Z ECMWF RUN ERY ENUF TO PERUSE BEFORE GOING TO PRESS WITH GRIDS. LONG WAY TO SAY LTL CHG TO GOING FCST WHICH HEDGES TWRDS COOLER TEMPS IN N AND COOLING TREND TWRD THE END OF THE WEEK. POTENTIAL FOR SGFNT CHGS TO FCST POPS/TEMPS DEPENDING ON HOW THIS UNFOLDS. && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 79 59 80 64 / 10 10 10 30 HUTCHINSON 79 58 81 64 / 10 20 10 30 NEWTON 79 59 81 64 / 10 10 10 30 ELDORADO 79 58 81 64 / 10 10 10 30 WINFIELD-KWLD 80 59 79 64 / 10 10 10 30 RUSSELL 76 56 80 62 / 10 20 10 30 GREAT BEND 77 57 80 63 / 10 30 10 30 SALINA 79 58 81 64 / 10 10 10 30 MCPHERSON 79 58 81 63 / 10 20 10 30 COFFEYVILLE 80 56 82 62 / 10 10 10 20 CHANUTE 79 55 79 62 / 10 10 10 20 IOLA 79 54 79 62 / 10 10 10 20 && .ICT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 17/HOWERTON ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 215 AM MDT SAT AUG 14 2004 .DISCUSSION...FORECAST CHALLENGES REMAIN AROUND PLACEMENT AND CONFIDENCE IN WEATHER/POP FORECAST AS A SLOW WARMUP CONTINUES ACROSS THE AREA. AT 0800Z CONVECTIVE CELLS HAD BEGUN OVER OUR FAR SOUTHERN ZONES AND POINTS SOUTH. CURRENT 06Z ETA AS WELL AS THE 00Z RUN AND THE CURRENT RUC CONTINUE TO GENERATE A BIT MORE COVERAGE OVER THE EASTERN 1/3 OF THE AREA WHERE ELEVATED CIN VALUES ARE LEAST AND MID LEVEL MOISTURE THE HIGHEST. THE 09Z FORECAST FROM THE ADJAVN GUIDANCE HAD THE SOUTHERN ACTIVITY PRETTY WELL SO USED IT FOR THE SHORT TERM. TODAY-SUNDAY...HIGH PRESSURE CONTINUES TO INFLUENCE THE AREAS WEATHER UNDERNEATH A WEST COAST RIDGE AND EAST COAST TROUGH. THIS NECK OF THE WORLD KIND OF CAUGHT IN BETWEEN WITH VARYING INTENSITIES OF 850 WARMING BY THE MODELS. FOR TODAY THERE IS BETTER AGREEMENT WITH A GENERAL 1-3F WARMUP FROM FRIDAYS READINGS. FOR SUNDAY THE ETA/UKMET ARE MORE AGGRESSIVE IN THEIR 850 WARMING WHEN COMPARED TO THE GFS/ECMWF AND NGM. AVERAGING THE GFS/ETA/NGM GIVES A WARMUP OF 4- 7F FROM SATURDAYS EXPECTED READINGS. THIS AVERAGING OF THE 850 WARMUP ALSO MATCHES THE MAV/FWC/ETA MOS GUIDANCE WARMUP AS WELL SO WILL LEAN TOWARD THAT SOLUTION. AS FAR AS PRECIP CHANCES...GREATEST INSTABILITY AND LESS CIN AS WELL AS 850/700 THETA-E AXIS AND APPROACHING MID LEVEL WAVE FROM THE NORTHWEST FAVOR MOSTLY OUR COLORADO COUNTIES ONCE AGAIN LATE IN THE DAY TODAY. AS THIS WAVE MOVES SOUTHEAST LOW LEVEL JET REDEVELOPS OVER THE AREA. ETA 850-700 CIN VALUES ARE WEAKEST OVER THE EASTERN 1/3 OF OUR AREA WHICH MATCHES ITS QPF FORECAST PRETTY WELL...MOSTLY AFTER 06Z. THINGS HEAT UP ONCE AGAIN SUNDAY AFTERNOON BUT IF THE ETA TEMPERATURES ARE TOO HIGH THEN THE CONVECTIVE TEMPS MAY NOT BE MET. SURFACE AND 850-700 CIN AS WELL AS 700-500 MOISTURE WOULD AGAIN FAVOR THE WESTERN 1/2 OF THE AREA. SUNDAY NIGHT...FRONTAL BOUNDARY MAKES ITS WAY TOWARD THE AREA WITH PRETTY SIMILAR SOLUTIONS FROM THE ETA/GFS. 6 HOUR PRESSURE RISES ONLY ABOUT 0-3MB SO THEIR ISNT A GREAT PUSH BEHIND IT. WILL KEEP SOME SMALL POPS ALONG AND AHEAD OF IT. MONDAY/MONDAY NIGHT...SOME TIMING ISSUES ON WHEN/HOW FAR THE FRONT GETS THROUGH THE AREA WITH THE ETA A BIT STRONGER PER ITS NORTHEAST WIND FORECAST THROUGH THE AREA. GFS HAS THE FRONT A BIT FURTHER NORTH. EITHER WAY...EXPECT STORMS TO FIRE IN THE AFTERNOON ALONG THE BOUNDARY WHEREVER IT MAY SHOW UP. WILL TEND TO THINK THAT FOR NOW WILL COMPROMISE WITH A MCCOOK TO GOODLAND TO CHEYENNE WELLS LINE AND POINTS SOUTH OF IT (NORTHEAST TO SOUTHWEST ORIENTATION). TEMPERATURES AT 850 CONTINUE TO WARM DESPITE THE NORTHEAST WINDS WITH A GENERAL 2F (KITR) TO 10F (KHLC) WARMUP PER ETA/GFS 850 TEMPERATURES. THIS IS SUPPORTED BY MANY OF THE OTHER MODELS AS WELL AND ISNT ALL THAT FAR OFF FROM THE VARIOUS MOS GUIDANCE NUMBERS. TUESDAY-FRIDAY...LATEST GFS NOT ALL THAT DIFFERENT FROM PREVIOUS RUN...ADVERTISING A LARGE CHUNK OF THE UPPER LOW IN ALASKA TO MOVE SOUTH AND/OR SOUTHEASTWARD...POSSIBLY GIVEN OUR NECK OF THE WOODS A GLANCING BLOW OF COOLER AIR WHEN COMPARED TO THE PREVIOUS RUN. GIVEN THE LACK OF DETAILS AND THE IMPACT OF RUNNING WITH ONE RUN VS ANOTHER WILL LEAVE CURRENT FORECAST AS IS. IT DOES LOOK HOWEVER THAT WE REMAIN NEAR OR SLIGHTLY BELOW NORMAL. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ DDT ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 400 AM EDT SAT AUG 14 2004 .SHORT TERM... OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO ASSESS CHANCES FOR ANY SHOWERS TODAY. THE SFC WX MAP EARLY THIS A.M. SHOWS A BROAD HIGH PRESSURE RIDGE IS GRADUALLY BUILDING INTO OUR AREA. IR SAT IMAGERY AND SFC OBS INDICATE THAT SKIES ARE CLEARING ACROSS MOST OF OUR CWA AS A RESULT. THIS CLEARING IS ALLOWING PATCHY FOG TO DEVELOP, BUT THAT SHOULD BURN OFF PRETTY QUICKLY BETWEEN 11Z AND 13Z. THEN AFTER A FAIR AMOUNT OF SUN THROUGH LATE MORNING, IT APPEARS A FAIR AMOUNT OF CU WILL DEVELOP, MAINLY SOUTH (ETA CU PROG SHOWS SCT TO BKN SKY CONDITIONS THIS AFTN). ADDITIONALLY, A SHARP H5 SHORTWAVE WILL MOVE THROUGH THIS AFTN AND EARLY EVENING. DUE TO THAT AND INSTABILITY GENERATED FROM SFC HEATING AND THE COLD AIR ALOFT, WE BELIEVE SCT SHOWERS WILL POP THIS AFTN AND LINGER INTO THE EARLY EVENING HOURS. LI'S FALLING TO NEAR ZERO WITH TOTAL TOTALS APPROACHING 50 AND SB CAPES AROUND 200-300 J/KG IS ALSO INDICATIVE OF SHOWER POTENTIAL (STEEP LAPSE RATES PROGGED FROM THE SFC UP TO AROUND 700 MB TOO). THE GFS, ETA-12 AND RUC-13 ALL SHOW A FEW SHOWERS WILL DEVELOP, MAINLY BETWEEN 18Z AND 00Z, WITH THE BEST CHANCE FOR THOSE OVER OUR EASTERN AND SOUTHERN CWA. WE COULD SEE GOING CHC POPS FOR SCT SHOWERS BUT AFTER COORD WITH DTX/APX OPTED TO STICK WITH ISOLATED WORDING. AFTER A FEW LINGERING EVENING SHOWERS, SKIES WILL CLEAR PRETTY QUICKLY TONIGHT IN SUBSIDENCE DIRECTLY UNDERNEATH THE SFC HIGH PRESSURE RIDGE. THAT SFC HIGH WILL PRODUCE CLEAR TO PARTLY CLOUDY SKIES SUNDAY, AND MAX TEMPS WILL REACH THE MID 70'S. IN FACT THE HIGH PRESSURE RIDGE WILL CONTINUE TO PRODUCE CLEAR TO PARTLY CLOUDY SKIES SUNDAY NIGHT THROUGH MONDAY AFTERNOON, AND SW RETURN FLOW ON THE BACK SIDE OF THE HIGH MONDAY WILL ALLOW MAX TEMPS TO REACH THE UPPER 70'S TO NEAR 80 DEGREES. WARMER WX FINALLY RETURNS! A COLD FRONT WILL GRADUALLY APPROACH OUR AREA MONDAY NIGHT, SO WE'LL CONTINUE TO MENTION A CHC OF SHOWERS/TSTORMS BY THEN TO ACCOUNT FOR THAT. .LONG TERM... LATEST MEDIUM RANGE GUIDANCE IS IN DECENT AGREEMENT REGARDING THE TIMING OF THE TROUGH PASSING THROUGH THE GREAT LAKES REGION ON TUESDAY AND TUESDAY NIGHT. A SHOWER AND TSTM CHANCE APPEARS WARRANTED FOR THE PASSAGE OF THIS FEATURE. WEDNESDAY CURRENTLY LOOKS LIKE A DRY AND SEASONAL DAY AS THE NEXT UPPER TROUGH BEGINS TO DIG UPSTREAM. THE LATEST 00Z OPERATIONAL RUNS ARE SLOWING THE PROGRESSION OF THE NEXT TROUGH AND ASSOCIATED COLD FRONT. THIS HAS HUGE IMPLICATIONS ON HIGH TEMPERATURES FOR THURSDAY...AND WILL BEGIN TO TREND A LITTLE WARMER THAN PREVIOUSLY FORECASTED. AFTER FROPA IT LOOKS LIKE ANOTHER FAIRLY SIGNIFICANT COOL DOWN FOR LATE IN THE WEEK. HOWEVER IT'S HARD TO SAY AT THIS POINT JUST HOW COLD SINCE THE UPPER TROUGH DOES NOT APPEAR TO DIG/PENETRATE AS FAR SOUTH AS THE ONE WHICH HAS BEEN AFFECTING THE GREAT LAKES REGION RECENTLY. SURFACE RIDGING BUILDING IN BEHIND THE FRONT SHOULD USHER IN A DRY WEATHER PERIOD TOWARD NEXT WEEKEND. && .GRR WATCHES/WARNINGS/ADVISORIES...NONE $$ LAURENS MEADE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 310 AM EDT SAT AUG 14 2004 .DISCUSSION... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW FAMILIAR UPR AIR PATTERN...DEEP UPR TROF IN ERN NAMERICA DOWNSTREAM OF HI AMPLITUDE RDG IN THE ROCKIES. CWA DIRECTLY UNDER TROF AXIS AND H5/H7 THERMAL TROF (H5/H7 TEMPS -21C/-5C). DESPITE FAIRLY DRY LLVL AIR AS SHOWN ON 00Z GRB/INL SDNGS...H85-7 LAPSE RATES STEEP ENUF (7.0-7.5C/KM) FOR SOME ISOLD -SHRA OVER AREAS NR THE WI BORDER THIS AFTN. ISOLD -SHRA ALSO NOTED OVER MN AND ACROSS ONTARIO JUST N OF LK SUP. SHRA HAVE ENDED...BUT SCT MID CLD LINGERS OVER NRN LK SUP AND ADJOINING ONTARIO. THIS CLD TENDING TO DRIFT SLOWLY S IN THE NLY FLOW ALF. 00Z YPL SDNG SHOWS INFLUENCE OF SHRTWV RIDGE ANALZD OVER NW ONTARIO... WITH A MUCH WARMER MID TROP/STRONG SUBSIDENCE INVRN ABV H8. MAIN FCST CONCERNS IN THE SHORT TERM ARE POTENTIAL FOR MORE ISOLD -SHRA TDAY...TEMPS TNGT/SUN...THEN TIMING OF NEXT SHRA CHC SUN NGT/MON ASSOCIATED WITH NEXT SHRTWV FCST TO RIDE OVER ROCKIES RDG AND DROP SE INTO THE GRT LKS ON BACK SIDE OF PERSISTENT ERN TROF. FOR TDAY...MODELS SHOW UPR GRT LKS COMING UNDER INFLUENCE OF SHRTWV RDG NOW IN NW ONTARIO...WITH ACCOMANYING SUBSIDENCE/DNVA/H85-3 QVECTOR DVGC/H4-2 CNVGC AIDING IN RISING H5/H7 HGTS. H5/H7 TEMPS FCST ABOUT 2C HIER THAN YDAY...AND FLOW ALSO MORE ACYC UNDER RISING HTGS REGIME. BUT ETA STILL SHOWING H85-7 LAPSE RATES IN THE 7.0- 7.5C/KM RANGE. FCST SDNGS SHOW THE STEEP LAPSE RATES...BUT FCST MID LVL SUBSIDENCE INVRN QUITE SHARP (SIMILAR TO 00Z YPL SDNG). SO ETA FCST KINX 23 TMRW AFTN AT IRON RIVER...AS COMPARED TO 27 ON FRI. EVEN FOR SFC DWPTS APRCHG 50...MODEL FCST SDNGS SHOW JUST OVER 100 J/KG CAPE. CONSIDERING NEGATIVE DYNAMICS...DECREASED INSTABILITY... AND JUST ISOLD COVG YDAY WHEN CONDITIONS WERE MORE FVRBL...HAVE OPTED TO KEEP FCST DRY EVEN THOUGH SOME MDT CU WL LIKELY DVLP UNDER STRENGTHENING MID LVL SUBSIDENCE INVRN. MIXING TO NR H7 ON ETA FCST SDNGS YIELDS TMAX IN THE LO 70S AWAY FM LK INFLUENCE. MORE OF A LLVL ACYC SW FLOW WL TEND TO RETARD LK BREEZE INFLUENCE/MODERATION. TNGT WL BE TRANQUIL WITH RDG/DRY AIRMASS FCST TO REMAIN DOMINANT. WITH CONTD NEGATIVE DYNAMICS AND LOSS OF DIURNAL HTG...LINGERING CU SHOULD DSPT QUICKLY. A MORE STEADY WSW FLOW WL LIMIT DIURNAL DROP IN TEMP...ESPECIALLY OVER THE WRN ZNS WHERE PRES GRADIENT IS PROGGED TO BE SHARPER FARTHER FM THE SFC HI CENTER OVER LWR MI. SHRTWV RDG/DRY AIRMASS FCST TO LINGER OVER FA ON SUN...SO LOOK FOR A DRY DAY WITH AN ACYC SW FLOW ARND SFC HI NOT FAR FM DET. GFS/ETA BOTH SHOW H85 TEMPS REACHING ARND 10C BY LATE IN THE DAY (ABOUT 1C HIER THAN TDAY). ETA FCST SDNGS FOR SUN AFTN LOOK VERY SIMILAR TO THOSE VALID FOR THIS AFTN... WITH A WELL MIXED BUT RATHER DRY PBL BLO SHARP MID LVL SUBSIDENCE INVRN. SOME POSITIVE AREA (FCST CAPE ARND 175 J/KG) WL ALLOW MORE DIURNAL CU DVLPMNT...BUT XPCT NO SHRA WITH SHARP INVRN/LO CAPE/DRY PBL. MIXING TO INVRN BASE NR H7 YIELDS TMAX APRCHG 75 AWAY FM LK INFLUENCE...WHICH WL AGAIN BE LIMITED BY THE WSW FLOW. IN FACT...HIEST TMAX MAY BE NEAR LK SUP IN AREAS THAT DOWNSLOPE OFF HURON MTNS WITH WSW FLOW. MODEL CONSENSUS HAS BEEN TO TRACK INCOMING SHRTWV IN NW FLOW ALF FARTHER S SUN NGT/MON SO THAT RDG/DRIER AIR HOLDS IN LONGER OVER THE UPR GRT LKS. ALL MODEL QPF NOW HAS PCPN ARRIVAL DELAYED OVER THE FAR W UNTIL MON MRNG AND IN THE E UNTIL AT LEAST MON EVNG. CONSIDERING THE HI AMPLITUDE UPR FLOW IN PLACE...THINK THESE TRENDS ARE LOGICAL. HAVE DELAYED ONSET OF PCPN AT IWD UNTIL MON MRNG AND AT ERY UNTIL MON EVNG. CONSIDERING ANTECEDENT DRY AIRMASS...PASSAGE OF BEST DPVA/ QVECTOR CNVGC TO THE S SUGS NO MORE THAN 30-40 POPS. ALTHOUGH EXPLICIT MODEL OUTPUT INDICATES PCPN WL END SOONER THAN FCST NOW ON TUE...HAVE MADE NO CHGS ATTM DUE TO TREND FOR LATER ARRIVAL OF SHRA AND UNCERTAINTY ON TIMING INCOMING SHRTWVS IN NW FLOW ALF. COORDINATED WITH APX/GRB/DLH. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 135 AM EDT SAT AUG 14 2004 .AVIATION (06Z-06Z) THE AC DECK CONTINUED TO ERODE THIS MORNING. WITH THE CLEARING SKIES...THERE WILL BE SOME FOG DEVELOPMENT...WITH THE BEST CHANCE AT KCVG/KLUK WHERE DEW POINTS ARE HIGHEST. MVFR CONDITIONS ARE LIKELY AT KCVG/KDAY/KILN/ KCMH WITH IFR VSBYS EXPECTED AT KLUK. ETA CU RULE AND FCST SNDGS POINTING TO BKN CU TODAY WITH SKIES CLEARING OUT THIS EVENING. && PREVIOUSLY ISSUED AT 958 PM EDT FRI AUG 13 2004 SHORT TERM UPDATE (TONIGHT) STILL A GOOD DEAL OF SC/AC ACRS FCST AREA THIS EVNG...BUT CLOUDS ARE CONTINUING TO THIN. HAVE SEEN A FEW RENEGADE -SHRA UP NEAR KFWA...AND MAY BE GETTING A SPRINKLE OR TWO ACRS WEST CNTRL OH. HOWEVER...RADAR RETURNS ARE DECREASING AND LARGE AREA OF NVA NOTED ON RUC 500 MB PROG MOVNG IN FROM WEST...SO NOT EXPECTING ANY PCPN REST OF NIGHT. CURRENT RUC DATA ALSO INDCG GOOD AMOUNT OF MOISTURE TO HANG ON AT 700/850 MB LVLS FOR MUCH OF NIGHT. WHILE CLOUDS SHOULD CONTINUE TO THIN AND DECREASE IN COVERAGE AS NIGHT PROGRESSES...AM NOT AS CONFIDENT THAT WE WILL COMPLETELY CLEAR OUT ACRS FCST AREA. HAVE ADJUSTED TO SKIES BECMG PTLY CLDY OVERNIGHT AS A RESULT. STILL THINKING THERE WILL BE ENUF BREAKS IN THE CLOUDS FOR SOME PATCHY FOG TOWARDS DAWN. ONLY OTHER CHANGE WAS TO BUMP OVERNIGHT LOWS UP A DEGREE OR TWO WITH MORE CLOUDS EXPECTED. UPDATE ALREADY OUT. && PREVIOUSLY ISSUED AT 335 PM EDT FRI AUG 13 2004 SHORT TERM (TONIGHT THROUGH SUNDAY NIGHT)... H5 TROF REMAINS LOCKED OVER THE GREAT LAKES WAITING FOR BONNIE AND CHARLEY TO CLEAR THE EAST COAST. MUCH OF THE CU WEST OF CENTRAL INDIANA APPEARS CONVECTIVE AND EXPECT IT TO DRY QUICKLY AFTER SUNSET. THEREFORE WILL GO WITH A FORECAST OF CLEARING SKIES. SKIES WILL CU AGAIN TOMORROW. MODELS ARE NOW FORECASTING ANOTHER H5 SHORTWAVE TO DROP INTO THE TROF SAT INTO SUNDAY. THIS WAVE SWINGS ACROSS THE FA ON SUN...SO WILL GO WHICH LOW CHANCE POPS ON SUNDAY. WENT BELOW GUIDANCE FOR HIGHS SAT AND SUNDAY. && PREVIOUSLY ISSUED AT 335 PM EDT FRI AUG 13 2004 LONG TERM (MONDAY THROUGH FRIDAY)... MODELS ARE CONSISTENT WITH PREVIOUS RUNS SO THERE WILL BE LITTLE CHANGE TO THE EXTENDED. DRY WEATHER IS STILL EXPECTED EARLY NEXT WEEK. WILL CONTINUE TO CARRY CHANCE TSRA WEDNESDAY AND THURSDAY WITH APPROACH AND PASSAGE OF A COLD FRONT. WILL LINGER SLIGHT CHANCE INTO FRIDAY MORNING BEHIND THE FRONT. AREA WILL BE UNDER A WARMER SOUTHWEST FLOW FOR MOST OF THE PERIOD SO TEMPERATURES WILL APPROACH CLIMATOLOGICAL AVERAGES. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. IN...NONE. KY...NONE. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 946 AM EDT SAT AUG 14 2004 .DISCUSSION...A LARGE AMPLITUDE LONG WAVE TROUGH EXTENDS FROM HUDSON BAY ALL THE WAY S INTO THE WRN GULF OF MEXICO. THIS TROUGH WILL STEER HURRICANE CHARLEY UP THE ENTIRE ERN SEA BOARD. THE HURRICANE IS NEARING ITS THIRD LANDFALL THIS MORNING...ALONG THE SC COAST. A STATIONARY FRONT STRETCHES ACROSS OUR SC GA AND FL BIG BEND ZONES. AREAS RADARS SHOW SHOWERS AND ISOLATED THUNDERSTORMS TO THE E OF THE BOUNDARY OVER THE APALACHEE BAY. SOME OF THE SHOWERS ARE MOVING ASHORE INTO THE ERN BIG BEND. HOWEVER, THIS ACTIVITY IS DIMINISHING. AREAS W OF THE FRONT SHOULD STAY DRY TODAY. POPS WILL BE LOWERED TO THE NW OF THE BOUNDARY. && .MARINE...SENT AN EARLY UPDATE TO ACCOUNT FOR THE HIGH SEAS OBSERVED OVER OUR WRN LEGS. EXERCISE CAUTION HEADLINE COVERED THIS. NOW, WINDS AND SEAS ARE BOTH DIMINISHING AND THIS TREND WILL CONTINUE THIS AFTERNOON. SO WE WILL BE ABLE TO PULL THE HEADLINE AT 1430Z. THE FRONT CONTINUES TO BISECT OUR ERN LEG, MAKING THE WIND FORECAST TRICKIER THERE. THE LATEST RUC MAINTAINS NE WINDS FOR MOST OF THE DAY. MOST OF THE CONVECTION SHOULD MOVE NORTHEAST OF THE AREA THIS AFTERNOON AND WILL INDICATE THIS IN THE NEXT ISSUANCE. && .FIRE WEATHER...NO CONCERNS. && .PREV DISCUSSION... 300 AM EDT SAT AUG 14 2004 SYNOPSIS...CHARLEY OFFSHORE OF JAX. STATIONARY FRONT STRETCHED ACROSS THE EASTERN SECTIONS OF OUR CWA. ASSOCIATED SHOWERS EXTEND DOWN FROM CENTRAL GA THROUGH TLH SOUTHWESTWARD INTO THE CENTRAL GULF OF MEXICO. SHORT TERM...STATIONARY FRONT STAYS WITH US FOR THE MOST PART... THROUGH THE EARLY PART OF NEXT WEEK. LITTLE CHANGE TO OCCUR WITH THE UPPER AIR PATTERN UNTIL MIDWEEK...THAT IS...RIDGE IN THE WEST AND A TROUGH IN THE EAST. THE TROUGH GRADUALLY FLATTENS OUT THO BEFORE SEVERAL PULSES BEGIN TO MOVE OUR WAY AT MIDWEEK. WILL REFLECT AN EAST TO WEST VARIATION IN WEATHER...POPS AND SKY DUE TO THE FRONT. LONG TERM...NO CHANGES MADE TO THE GRIDS. && .PRELIMINARY POINT TEMPS/POPS... TLH 87 67 89 68 / 30 10 20 10 PFN 86 68 88 72 / 20 10 10 10 DHN 85 64 88 68 / 10 10 00 00 ABY 86 66 90 68 / 20 10 10 00 VLD 87 69 88 68 / 30 10 30 10 CTY 87 69 87 70 / 40 20 40 20 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. && $$ WATSON (PREVIOUS DISCUSSION) WOOL (CURRENT DISCUSSION) fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 820 AM MDT SAT AUG 14 2004 .UPDATE... PATCHY FOG HAS WORKED INTO THE WEST/SOUTHWEST ZONES...MAINLY ALONG AND WEST OF A LINE FROM STRATTON TO KIT CARSON WHICH SHOULD GRADUALLY DIMINISH BY LATE MORNING. WILL ALSO REMOVE MENTION OF MORNING POPS ACROSS THE EASTERN ZONES AS ACITIVITY APPEARS TO REMAIN EAST OF A LINE FROM NORTH PLATTE TO HOLDREDGE TO AROUND SMITH CENTER. NO CHANGE TO AFTERNOON WORDING AT THIS POINT...WITH ISOLATED THUNDERSTORMS DEVELOPING BY AFTERNOON WITH GREATEST THREAT ALONG AND WEST OF THE KANSAS COLORADO BORDER. MWM && .PREV DISCUSSION... 215 AM MDT SAT AUG 14 2004 FORECAST CHALLENGES REMAIN AROUND PLACEMENT AND CONFIDENCE IN WEATHER/POP FORECAST AS A SLOW WARMUP CONTINUES ACROSS THE AREA. AT 0800Z CONVECTIVE CELLS HAD BEGUN OVER OUR FAR SOUTHERN ZONES AND POINTS SOUTH. CURRENT 06Z ETA AS WELL AS THE 00Z RUN AND THE CURRENT RUC CONTINUE TO GENERATE A BIT MORE COVERAGE OVER THE EASTERN 1/3 OF THE AREA WHERE ELEVATED CIN VALUES ARE LEAST AND MID LEVEL MOISTURE THE HIGHEST. THE 09Z FORECAST FROM THE ADJAVN GUIDANCE HAD THE SOUTHERN ACTIVITY PRETTY WELL SO USED IT FOR THE SHORT TERM. TODAY-SUNDAY...HIGH PRESSURE CONTINUES TO INFLUENCE THE AREAS WEATHER UNDERNEATH A WEST COAST RIDGE AND EAST COAST TROUGH. THIS NECK OF THE WORLD KIND OF CAUGHT IN BETWEEN WITH VARYING INTENSITIES OF 850 WARMING BY THE MODELS. FOR TODAY THERE IS BETTER AGREEMENT WITH A GENERAL 1-3F WARMUP FROM FRIDAYS READINGS. FOR SUNDAY THE ETA/UKMET ARE MORE AGGRESSIVE IN THEIR 850 WARMING WHEN COMPARED TO THE GFS/ECMWF AND NGM. AVERAGING THE GFS/ETA/NGM GIVES A WARMUP OF 4- 7F FROM SATURDAYS EXPECTED READINGS. THIS AVERAGING OF THE 850 WARMUP ALSO MATCHES THE MAV/FWC/ETA MOS GUIDANCE WARMUP AS WELL SO WILL LEAN TOWARD THAT SOLUTION. AS FAR AS PRECIP CHANCES...GREATEST INSTABILITY AND LESS CIN AS WELL AS 850/700 THETA-E AXIS AND APPROACHING MID LEVEL WAVE FROM THE NORTHWEST FAVOR MOSTLY OUR COLORADO COUNTIES ONCE AGAIN LATE IN THE DAY TODAY. AS THIS WAVE MOVES SOUTHEAST LOW LEVEL JET REDEVELOPS OVER THE AREA. ETA 850-700 CIN VALUES ARE WEAKEST OVER THE EASTERN 1/3 OF OUR AREA WHICH MATCHES ITS QPF FORECAST PRETTY WELL...MOSTLY AFTER 06Z. THINGS HEAT UP ONCE AGAIN SUNDAY AFTERNOON BUT IF THE ETA TEMPERATURES ARE TOO HIGH THEN THE CONVECTIVE TEMPS MAY NOT BE MET. SURFACE AND 850-700 CIN AS WELL AS 700-500 MOISTURE WOULD AGAIN FAVOR THE WESTERN 1/2 OF THE AREA. SUNDAY NIGHT...FRONTAL BOUNDARY MAKES ITS WAY TOWARD THE AREA WITH PRETTY SIMILAR SOLUTIONS FROM THE ETA/GFS. 6 HOUR PRESSURE RISES ONLY ABOUT 0-3MB SO THEIR ISNT A GREAT PUSH BEHIND IT. WILL KEEP SOME SMALL POPS ALONG AND AHEAD OF IT. MONDAY/MONDAY NIGHT...SOME TIMING ISSUES ON WHEN/HOW FAR THE FRONT GETS THROUGH THE AREA WITH THE ETA A BIT STRONGER PER ITS NORTHEAST WIND FORECAST THROUGH THE AREA. GFS HAS THE FRONT A BIT FURTHER NORTH. EITHER WAY...EXPECT STORMS TO FIRE IN THE AFTERNOON ALONG THE BOUNDARY WHEREVER IT MAY SHOW UP. WILL TEND TO THINK THAT FOR NOW WILL COMPROMISE WITH A MCCOOK TO GOODLAND TO CHEYENNE WELLS LINE AND POINTS SOUTH OF IT (NORTHEAST TO SOUTHWEST ORIENTATION). TEMPERATURES AT 850 CONTINUE TO WARM DESPITE THE NORTHEAST WINDS WITH A GENERAL 2F (KITR) TO 10F (KHLC) WARMUP PER ETA/GFS 850 TEMPERATURES. THIS IS SUPPORTED BY MANY OF THE OTHER MODELS AS WELL AND ISNT ALL THAT FAR OFF FROM THE VARIOUS MOS GUIDANCE NUMBERS. TUESDAY-FRIDAY...LATEST GFS NOT ALL THAT DIFFERENT FROM PREVIOUS RUN...ADVERTISING A LARGE CHUNK OF THE UPPER LOW IN ALASKA TO MOVE SOUTH AND/OR SOUTHEASTWARD...POSSIBLY GIVEN OUR NECK OF THE WOODS A GLANCING BLOW OF COOLER AIR WHEN COMPARED TO THE PREVIOUS RUN. GIVEN THE LACK OF DETAILS AND THE IMPACT OF RUNNING WITH ONE RUN VS ANOTHER WILL LEAVE CURRENT FORECAST AS IS. IT DOES LOOK HOWEVER THAT WE REMAIN NEAR OR SLIGHTLY BELOW NORMAL. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ DDT ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1132 AM EDT SAT AUG 14 2004 .UPDATED... A QUICK UPDATE TO ADJUST FOR AFTERNOON WORDING. MORE OR LESS THE GOING FORECAST SEEMS FINE TO ME. PARTLY CLOUDY SKIES...ISOLATED AFTERNOON SHOWERS WITH HIGHS NEAR 70F SEEMS THE WAY TO GO FOR THIS AFTERNOON. THE MORNING SOUNDING FROM AROUND THE GREAT LAKES SHOW WELL HOW THERE IS SIGNIFICANTLY MORE MOISTURE NEAR AND SOUTH OF INTERSTATE 96 BELOW 700 MB (COMPARE DTX 12Z SOUNDING TO APX AND GRB). THE ETA AND RUC AGREE THAT A 500 CLOSED LOW WILL TRY TO CLOSE OFF OVER SRN LK MICHIGAN BY 00Z THIS EVENING. THEN IT WILL DRIFT EVER SO SLOWLY TOWARD THE DETROIT AREA BY 18Z SUNDAY AND TO PORT HURON BY 00Z MONDAY. THIS PUTS THE SOUTHERN PART OF LOWER MICHIGAN IN THE Q VECTOR CONVERGENCE AREA THIS AFTERNOON INTO THIS EVENING. SINCE THIS IS ALSO THE AREA WITH THE SFC TO 700 MB DEW POINTS ARE HIGHEST...IT IS ALSO THE AREA WITH LOWEST LI VALUES AND HIGHEST EQUILIBRIUM LEVELS. PROBLEM IS THERE IS CONSIDERABLE DIRECTIONAL WIND SHEAR (VELOCITY ONLY 5 TO 10 KTS) NEAR 700MB. LIKE NORTHEAST BELOW 700MB AND SOUTHWEST ABOVE 700MB. SO...BELIEVE THE PARTLY CLOUDY SKY THING IS FINE AS IS THE ISOLATED SHOWERS (CAPES WITH 74/47 NEAR LAN ARE LESS THAN 100 J/KG). BASED ON LOW LEVEL THICKNESS FIELDS...HIGH BETWEEN 68 AND 74F SEEM FINE FOR OUR CWA TODAY. TONIGHT MID CLOUDS COULD REDEVELOP AS THEY DID LAST NIGHT AS THE LOWER LEVEL COOL AND THE 500 LOW CREATES MID LEVEL LIFT OVER THE SRN CWA. WILL HAVE TO LOOK MORE AT THAT FOR THE AFTERNOON FORECAST...IT COULD ALLOW THE LOW TEMPERATURES TO STAY WARMER OVER THE SRN CWA. && .GRR WATCHES/WARNINGS/ADVISORIES...NONE $$ WDM mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE ABERDEEN SD 920 AM CDT SAT AUG 14 2004 .UPDATE...REVISITED GRIDS/WORDS TO REMOVE FOG VERBIAGE. REMAINDER OF FIRST PERIOD FORECAST LOOKS QUITE SATISFACTORY. DID TWEAK MAX T GRID UPWARD A COUPLE OF DEGREES GIVEN AMOUNT OF SUN EXPECTED TODAY AS WELL AS BASED ON LATEST 850HPA THERMAL PROGS IN RUC MODEL. ALSO TWEAKED HOURLY TEMP/DWPT/RH/WIND GRIDS. DORN .SHORT TERM...TODAY THROUGH MONDAY NIGHT BIGGEST CHALLENGE REMAINS FRONTAL PASSAGE SUNDAY NIGHT. A LITTLE PATCH FOG HAS APPEARED THIS MORNING WITH GOOD RADIATIONAL COOLING. SHOULD NOT BE TOO MUCH OF AN ISSUE AND WILL GO WITH SOME PATCHY DENSE FOR A FEW HOURS AFTER SUNRISE. NEXT ISSUE IS PRECIP THREAT WITH APPROACHING SHORTWAVE TROF AND ASSOCIATED FRONT ON SUNDAY NIGHT. ETA AND GFS AGREE FAIRLY WELL WITH ONSET...BUT DIFFER GREATLY WITH ENDING TIMES. ETA HINTS AT A FAIRLY WELL BEHAVED DIURNAL TREND...WITH MOST CONVECTION ENDING BY 06UTC MONDAY AND A FEW LINGERING POST FRONTAL SHOWERS THROUGH ABOUT 12 UTC. GFS SHOWS A MUCH LONGER EVENT...WITH PRECIP INDICATED THROUGHOUT MUCH ON THE DAY ON MONDAY. GIVEN SPEED OF UPPER TROF AND SURFACE FRONT...WILL KEEP CURRENT FORECAST TIMING WHICH REFLECTS AN ETA SOLUTION. BOTH MODELS INDICATE PRIMARY TYPE WILL BE CONVECTIVE WITH NEGATIVE LIFTED INDEX VALUES AND SURFACE BASED CAPE ON THE ORDER OF 1000 J/KG. SPC DAY 3 SLIGHT RISK AREA GRABS A GOOD PORTION OF EASTERN CWA AS WELL. BASED ON THESE FACTORS...HAVE UPPED POPS TO 40 IN EASTERN CWA. WHILE STILL IN CHANCE CATEGORY AS IN PREVIOUS FORECAST...WANTED TO SHOW INCREASING CONFIDENT TREND IN PRECIP EVENT. DID NOT MAKE ANY OTHER SIGNIFICANT CHANGES TO ONGOING FORECAST. .LONG TERM...TUESDAY THROUGH FRIDAY NOT A LOT OF CHANGES MADE TO THE EXTENDED PERIOD. MODELS CONTINUE TO SHOW A LARGE UPPER LOW SPINNING OVER THE NORTHERN CANADA/HUDSON BAY REGION THROUGHOUT THE PERIOD...WITH NORTHWEST FLOW OVER THE NORTHERN PLAINS. ALL THE SIGNIFICANT ENERGY REMAINS WELL NORTH OF THE AREA...WITH JUST ONE WEAK WAVE MOVING THROUGH WEDNESDAY NIGHT. THE LATEST MODEL RUNS INDICATE MUCH SLOWER TIMING WITH THE SURFACE FRONT...NOW LOOKING TO MOVE THROUGH ON WEDNESDAY NIGHT INSTEAD OF TUESDAY NIGHT. HOWEVER...WILL STICK WITH THE CONSENSUS OF SURROUNDING OFFICES AND NOT CHANGE THE TIMING FOR NOW...AS THIS IS THE FIRST MODEL RUN TO BRING THE FRONT THROUGH THAT MUCH LATER. WILL ALSO NOT MAKE ANY CHANGES TO TEMPERATURES. WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ HARDING/PARKIN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 200 PM MDT SAT AUG 14 2004 .SHORT TERM DISCUSSION...ATMOSPHERIC MIX SLOWLY COMING TOGETHER FOR WHAT APPEARS MAY BE AN ACTIVE LATE AFTERNOON AND EVENING ALONG THE FRONT RANGE...PALMER DIVIDE AND OUT ACROSS THE NERN PLAINS OF COLORADO. MODIFICATION OF THE LATEST ACARS SOUNDINGS OVER AND AROUND DENVER CRANKED OUT ICAPE VALUES IN THE 2000-2400 J/KG RANGE...BASED ON A PARCEL OF 81F/55F...WITH 80F THE CONVECTIVE TEMP FOR DENVER METRO AREA TODAY. CONVECTION GOING UP OVER THE FRONT RANGE SHOULD SEE CONTINUE TO DEVELOP AS THEY TRACK SEWRD OVER THE I-25 URBAN CORRIDOR AND PALMER DIVIDE LATE THIS AFTERNOON. EAST/NORTHEAST LOW-LEVEL FLOW IS FCST TO DEEPEN BUT NOT NECESSARILY STRENGTHEN. THIS LOW-LEVEL FLOW WILL KEEP THE HIGHER THETA-E VALUES UP ALONG THE FOOTHILLS AND MONUMENT RIDGE THROUGH THIS EVENING...BEFORE DRAINAGE FLOW DRIES THINGS OUT. WOULD NOT RULE OUT A COUPLE SEVERE STORMS OVER CENTRAL AND SOUTHERN URBAN CORRIDOR...THE ADJACENT HIGH PLAINS AND THE PALMER DIVIDE LATE THIS AFTERNOON AND EARLY THIS EVENING. LARGE HAIL AND DAMAGING WINDS APPEARS TO BE MAIN THREAT. HEAVY RAIN THREAT LOOKS LOW WITH PRECIPITABLE WATER VALUES BELOW 0.60 INCH AND STORM MOTIONS IN EXCESS OF 25 KTS. EAST/SOUTHEAST OF THE DENVER METRO AREA WHERE SFC DEWPOINTS ARE A FEW DEGS HIGHER...ALREADY SEEING LOW TOP CONVECTION GOING UP ALONG A WIND SHEAR AXIS EXTENDING N-S ACROSS EASTERN ADAMS...EASTERN ARAPAHOE AND CENTRAL ELBERT COUNTIES THIS HOUR...PRETTY MUCH THE SAME AREA BLANKETED BY FOG AND LOW STRATUS THROUGH MID-MORNING. RUC AND ETA MODEL SOUNDINGS SHOWED A PRETTY SUBSTANTIAL CAP AROUND 550 MB OVER THIS AREA AS OF 18Z...BUT SUSPECT ONCE TEMPS CLIMB INTO THE MID 70S...SHOULD SEE MULTICELL T-STORM FORMATION ALONG THIS SHEAR AXIS. ONCE STORMS GET GOING...OUTFLOW BOUNDARIES MAY HELP SPAWN A COUPLE SUPER CELLS CAPABLE OF VERY LARGE HAIL AND DAMAGING DOWNBURST WINDS. TONIGHT...ACTION AREA APPEARS TO SHIFT EAST/NORTHEAST TOWARDS THE NORTHEAST CORNER OF THE STATE THIS EVENING. MODEL SFC BNDRY LAYER CAPE VALUES UP AROUND 2500 J/KG AND MODEL SOUNDING HELICITY VALUES APPROACHING 110 M2/S2 AS OF 03Z. FURTHERMORE WEAK MID-LEVEL DISTURBANCE RACING OUT OF WY SHOULD PROVIDE ADDITIONAL LIFT FOR SEVERE T-STORM FORMATION. WOULD EXPECT MOST OF THIS CONVECTION TO END SOON AFTER MIDNIGHT DUE TO DRYING AND STABILIZATION AT MID-LEVELS. COULD SEE SOME STRATUS REDEVELOP OVERNIGHT OVER PORTIONS OF THE NERN PLAINS AS WELL. SUNDAY...AFTER A START OF LOW CLOUDS AND AREAS OF FOG ON THE PLAINS...SHOULD SEE RAPID WARMING WITH DRIER NWLY FLOW ALOFT MIXING DOWN ALONG THE FRONT RANGE. HOWEVER FARTHER OUT ON THE PLAINS...EAST OF THE LEE TROUGH...SFC GRIDS STILL KEEP DEW POINTS UP IN THE 50S. MODEL SOUNDINGS ALSO GENERATE SOME IMPRESSIVE CAPES AFTER 21Z...GENERALLY IN THE 1600-2100 J/KG RANGE. BUT MID-LEVELS LOOK PRETTY CAPPED DURING THE DAY. WILL GO WITH A SLIGHT CHANCE OF T-STORMS LATE IN ALL AREAS...BUT CHANCE FOR MEASURABLE PRECIP LOOKS QUITE LOW. TEMPS TOMORROW MAYBE A FEW DEGS ABOVE THOSE TODAY. .LONG TERM DISCUSSION...SUN NGT-TUE...MDLS KEEP NWLY FLO ALF ACRS CNTRL RCKYS THRU PRD. ON SUN EVE BEST INSTABILITY WILL BE NR NE CORNER WHERE CAPES ARE HIEST BUT FCST SOUNDINGS SHW WK CIN. HWVR ETA SHWS MST OF PCPN OVR URBAN CORRIDOR. WILL KEEP ISOLD STORMS IN FCST FOR NOW. FOR MON AFTN AND EVE FCST CAPES ARE LO WITH AS SFC HI PRES MOVES S INTO NERN PLAINS. MDLS SHW QUITE A BIT OF PCPN WITH THIS CDFNT...BUT AIR MASS MAY BCM CAPPED SO WILL KEEP POPS LO. ON TUE GFS BLOWS UP SFC LO OVR GRT BASIN AND MOVES IT INTO WRN CO. THIS FEATURE IS NOT APPARENT ON ETA. MSTR AND PCPN ACRS AREA IS OVERBLOWN ON GFS AS ETA SOLUTION LUKS MORE REASONABLE. WILL INCRS POPS TO SCT ON TUE AFT AND EVE. TEMPS WILL BE WARMER ON MON IN ADV OF CDFNT AND COOLER OVR PLAINS ON TUE. GENLY FVR THE GFS MOS TEMP GUIDANCE. IN EXTENDED PERIOD...WED-SAT...MDLS MAINTAIN UPR RDG OVR WRN U.S. WITH PERSISTENT NWLY FLO ALF ACRS CNTRL RCKYS. GFS SHOWS AMPLE MOISTURE AND PCPN ACRS AREA FOR A CHC OF AFTN AND EVE CONVECTION EACH DAY. TEMPS WILL BE SLIGHTLY BLO SEASONAL NORMS. && .BOU...WATCHES/WARNINGS/ADVISORIES...NONE. && BAKER/GARD...WFO BOULDER co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 230 PM EDT SAT AUG 14 2004 .CURRENTLY...SKIES RANGE FROM SUNNY NW TO MOSTLY CLOUDY SE SECTIONS OF CWFA. TEMPS IN LOW 80S...DEW POINTS FROM AROUND 60 SE ALA TO LOW 70S SE BIG BEND. WINDS FROM N 5-10 MPH SE ALA TO E 5 MPH SE BIG BEND. ISOLATED SHOWERS WERE NOTED ACROSS DIXIE COUNTY BUT MOIST PRECIP HAS BEEN SHUNTED SEWD OF OUR CWFA. && .DISCUSSION...LARGE AMPLITUDE LONG WAVE CONTS FORM ERN MOST CANADA S INTO GULF OF MEXICO PROVIDING SWLY STEERING FLOW. CHARLEY HAS WEAKENED TO A TROPICAL STORM AS IT MOVES N/NE NEAR 30 MPH OVER N CAROLINA. NEARLY STATIONARY SURFACE TROUGH EXTENDS SW FROM CHARLEY TO ACROSS NE FLA AND INTO SE MOST SECTIONS OF SE BIG BEND. N OF THE FRONT..HIGH PRESSURE AND NOTICEABLY DRIER AIR BUILDING IN RAPIDLY SEWD. SATTELITE WATER VAPOR LOOPS SHOWS DRY AIR WRAPPING AROUND BACK SIDE OF CHARLEY. THE TROUGH AND HI POSITIONS EXPLAIN THE SIGNIFICANT AIRMASS CONTRASTS NOTED ABOVE. FORECAST QUESTION IS FUTURE POSITION OF FRONT/TROF AND HOW MUCH OF CWFA REMAINS IN WARM SECTOR. WITH CHARLEY MOVING OUT..LACK OF PUSH FOR TROF..AND GUIDANCE SHOWS BOUNDARY DRIFTING E AND THEN BACK W NEXT FEW DAYS. MODELS DIFFER NOTICEABLY WITH GFS MUCH MORE AGGRESSIVE IN SHIFTING FRONT BACK WWD PLACING MORE OF OUR AREA IN WARM SECTOR/SW LO LEVEL FLOW. HARD TO JUSTIFY GFS SCT-LIKELY POPS AND WILL LEAN TOWARDS DRIER ETA. THUS FIVE ZONE ZFP WITH FLA DIVIDED W-E WITH WDLY SCT-MID SCT BREAK NEXT FEW DAYS. && .LONG TERM...UPR TROF TO FINALLY LIFT NEWD WITH RIDGING MOVING EWD OVER ERN CONUS MID-WEEK. TIME TO LOOK EWD AT TD FIVE..POSITION BRINGS IT TO HURRICANE STRENGTH AND INTO NW CARIB DAY 5. TRACK LOOKS OMINOUSLY LIKE BONNIE. && .MARINE...LOCAL GRADIENTS CONT TO WEAKEN. AFTERNOON BUOYS SHOW WINDS UP TO 4 FEET AND 10 KNOT SEAS OUTER WATER..LESS NEARSHORE. WILL CONT W/E SPLIT TO ACCOUNT FOR SLIGHTLY HIGHER WINDS/SEAS ERN WATERS IN WAKE OF CHARLEY. && .FIRE WX...NO CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... TLH 68 90 69 90/10 30 10 30 PFN 69 88 73 89/05 10 10 20 DHN 63 87 66 89/05 00 00 20 ABY 67 89 66 91/10 10 05 20 VLD 70 88 69 90/10 30 10 30 CTY 71 88 70 90/30 50 30 40 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. && $$ BLOCK ____________________________________________________________________ .PREV DISCUSSION... 946 AM EDT SAT AUG 14 2004 .DISCUSSION...A LARGE AMPLITUDE LONG WAVE TROUGH EXTENDS FROM HUDSON BAY ALL THE WAY S INTO THE WRN GULF OF MEXICO. THIS TROUGH WILL STEER HURRICANE CHARLEY UP THE ENTIRE ERN SEA BOARD. THE HURRICANE IS NEARING ITS THIRD LANDFALL THIS MORNING...ALONG THE SC COAST. A STATIONARY FRONT STRETCHES ACROSS OUR SC GA AND FL BIG BEND ZONES. AREAS RADARS SHOW SHOWERS AND ISOLATED THUNDERSTORMS TO THE E OF THE BOUNDARY OVER THE APALACHEE BAY. SOME OF THE SHOWERS ARE MOVING ASHORE INTO THE ERN BIG BEND. HOWEVER, THIS ACTIVITY IS DIMINISHING. AREAS W OF THE FRONT SHOULD STAY DRY TODAY. POPS WILL BE LOWERED TO THE NW OF THE BOUNDARY. && .MARINE...SENT AN EARLY UPDATE TO ACCOUNT FOR THE HIGH SEAS OBSERVED OVER OUR WRN LEGS. EXERCISE CAUTION HEADLINE COVERED THIS. NOW, WINDS AND SEAS ARE BOTH DIMINISHING AND THIS TREND WILL CONTINUE THIS AFTERNOON. SO WE WILL BE ABLE TO PULL THE HEADLINE AT 1430Z. THE FRONT CONTINUES TO BISECT OUR ERN LEG, MAKING THE WIND FORECAST TRICKIER THERE. THE LATEST RUC MAINTAINS NE WINDS FOR MOST OF THE DAY. MOST OF THE CONVECTION SHOULD MOVE NORTHEAST OF THE AREA THIS AFTERNOON AND WILL INDICATE THIS IN THE NEXT ISSUANCE. && .FIRE WEATHER...NO CONCERNS. && .PREV DISCUSSION... 300 AM EDT SAT AUG 14 2004 SYNOPSIS...CHARLEY OFFSHORE OF JAX. STATIONARY FRONT STRETCHED ACROSS THE EASTERN SECTIONS OF OUR CWA. ASSOCIATED SHOWERS EXTEND DOWN FROM CENTRAL GA THROUGH TLH SOUTHWESTWARD INTO THE CENTRAL GULF OF MEXICO. SHORT TERM...STATIONARY FRONT STAYS WITH US FOR THE MOST PART... THROUGH THE EARLY PART OF NEXT WEEK. LITTLE CHANGE TO OCCUR WITH THE UPPER AIR PATTERN UNTIL MIDWEEK...THAT IS...RIDGE IN THE WEST AND A TROUGH IN THE EAST. THE TROUGH GRADUALLY FLATTENS OUT THO BEFORE SEVERAL PULSES BEGIN TO MOVE OUR WAY AT MIDWEEK. WILL REFLECT AN EAST TO WEST VARIATION IN WEATHER...POPS AND SKY DUE TO THE FRONT. LONG TERM...NO CHANGES MADE TO THE GRIDS. && .PRELIMINARY POINT TEMPS/POPS... TLH 87 67 89 68 / 30 10 20 10 PFN 86 68 88 72 / 20 10 10 10 DHN 85 64 88 68 / 10 10 00 00 ABY 86 66 90 68 / 20 10 10 00 VLD 87 69 88 68 / 30 10 30 10 CTY 87 69 87 70 / 40 20 40 20 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. && $$ WATSON (PREVIOUS DISCUSSION) WOOL (CURRENT DISCUSSION) fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 328 PM EDT SAT AUG 14 2004 .DISCUSSION... MAIN FCST CONCERN IS PCPN POTENTIAL SUN-TUE. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW RIDGE PERSISTING N THRU THE ROCKIES TO ALASKA AND TROF EXTENDING FROM THE NPOLE S ACROSS ERN NAMERICA. NEXT SHORTWAVE OF INTEREST IS DIVING SE THRU NRN SASKATCHEWAN. FARTHER UPSTREAM...A STRONG SHORTWAVE WAS DIVING SE INTO THE NW TERRITORIES AS STRONG WRN RIDGE BUILDS EVEN FARTHER N. BY MID/LATE IN THE UPCOMING WEEK...THE STRONG WRN RIDGE WILL RESULT IN AN UNUSUALLY DEEP AUG POLAR VORTEX DEVELOPING VCNTY OF HUDSON BAY. AT THE SFC...HIGH PRES IS DOMINATING THE MID MISSISSIPPI VALLEY INTO THE WRN GREAT LAKES. COLD FRONT ASSOCIATED WITH SASKATCHEWAN SHORTWAVE EXTENDS FROM NRN MANITOBA THRU CNTRL SASKATCHEWAN. MODELS ARE IN GOOD AGREEMENT ON PROGRESSION OF SASKATCHEWAN SHORTWAVE AND COLD FRONT OVER THE NEXT FEW DAYS. IN THE MEANTIME... A TRANQUIL NIGHT EXPECTED TONIGHT AS FCST AREA REMAINS UNDER THE INFLUENCE OF HIGH PRES. WAA REMAINS FOCUSED WELL TO THE NW AND N... SO NOT EXPECTING MUCH IN THE WAY OF CLOUD COVER OTHER THAN SOME CI SPILLING SE. GOING MIN TEMP FCST LOOKS FINE...RANGING FROM MID 40S INTERIOR CNTRL/E TO LOW/MID 50S W WHERE LIGHT SW FLOW DEVELOPS. ON SUN...SW FLOW INCREASES IN ADVANCE OF APPROACHING COLD FRONT. EVEN SO...LITTLE IN THE WAY OF 850MB THETA-E ADVECTION IS INDICATED OVER UPPER MI. BEST WAA/THETA-E ADVECTION REMAINS TO THE NW. IN ADDITION...SHORTWAVE RIDGING IS OVER UPPER MI...AND ETA FCST SOUNDINGS SHOW DRY AIR LINGERING. ALL THIS ARGUES FOR A CONTINUED DRY FCST. THIS BACKED BY VERY LOW MOS POPS FROM THE MODELS...ALL UNDER 10. MIXING TO UPWARDS OF 800-750MB YIELDS HIGHS IN THE MID 70S...INLINE WITH VARIOUS MOS GUIDANCE AND GOING FCST. MID SHIFT PUSHED PCPN CHC BACK SUN NIGHT/MON AS TREND WAS FOR SASKATCHEWAN SHORTWAVE AND MAIN FORCING TO TRACK FARTHER S THAN E. THIS TREND HAS HELD UP WITH 12Z RUNS. RESULT IS DRY AIR HOLDING ON LONGER PER GFS AND ESPECIALLY ETA FCST SOUNDINGS. BULK OF THETA-E ADVECTION GETS HELD UP TO THE SW. AT THIS POINT...SEE NO REASON TO DEVIATE FROM GOING FCST WHICH BRINGS PCPN CHC INTO FAR W EARLY MON MORNING AND NOT REACHING E UNTIL EVENING. LATER MON/TUE...SFC BOUNDARY BECOMES MORE DIFFUSE AS IT MOVES THRU UPPER GREAT LAKES. THIS IS A RESULT OF ADDITIONAL SHORTWAVE ENERGY DROPPING SE TOWARD THE AREA IN STRENGTHENING NW FLOW. WILL MAINTAIN LOW END CHC POPS DURING THIS TIME UNTIL BOUNDARY MOVES E OF THE AREA TUE. WED-SAT...MODELS ARE IN QUITE GOOD AGREEMENT FOR THIS PERIOD AND INDICATE THAT SOME OF THE PREVIOUS MODEL RUNS WERE TOO AGGRESSIVE/QUICK WITH THE COOL DOWN MID WEEK. AGREEMENT IS GOOD ON A DEEP UNAUGUST-LIKE POLAR VORTEX DEVELOPING VCNTY HUDSON BAY AS ANOMALOUS HIGH HEIGHTS SPREAD ACROSS THE ARCTIC...ALMOST BRIDGING FROM ALASKA TO GREENLAND. AS POLAR VORTEX STRENGTHENS/DROPS S MIDWEEK...COLD FRONT WILL DROP SE INTO ONTARIO/MN LATE WED... CROSSING UPPER MI EARLY THU. MODELS ARE IN SURPRISINGLY GOOD AGREEMENT ON THIS TIMING. HOWEVER...12Z GFS HAS TRENDED FASTER... WITH FROPA NOW ON WED EVENING AND THEN COLDER THAN PREVIOUS RUN IN ITS WAKE. 12Z UKMET HAS MAINTAINED TIMING FROM PREVIOUS RUNS...AND HPC HAS KEPT WITH A THU MORNING FRONTAL PASSAGE HERE. WILL NOT JUMP ON 12Z GFS...BUT IT WILL BE A TREND TO MONITOR IN FUTURE MODEL RUNS. SHOULD BE ABLE TO SLIP IN A DRY WED DAYTIME WITH FRONT STILL WELL TO THE W. THERMAL RIDGE WITH 850MB TEMPS 14C OR BETTER PUSHING INTO UPPER MI WITH SW FLOW AHEAD OF FRONT WILL SEND TEMPS ABOVE NORMAL WED. SEE NO PROBLEM RAISING TEMPS TOWARD 80 MANY AREAS. WILL BRING SHRA/TSRA ACROSS THE AREA WED NIGHT/THU WITH COLD FRONT. FRI-SAT... WILL BE DIFFICULT TO DETERMINE PCPN CHANCES AS THERE WILL LIKELY BE SHORTWAVES ROTATING THRU THE AREA FROM TIME TO TIME IN CYCLONIC FLOW ON SRN EDGE OF LARGE POLAR VORTEX TO THE N. TEMPS WILL TREND BELOW NORMAL FRI/SAT...BUT NOT SIGNIFICANTLY AS AREA IS ONLY BRUSHED BY SRN EDGE OF COLD AIR MASS. IN ADDITION...GFS ENSEMBLE MEAN 850MB TEMPS RUN A FEW DEGREES WARMER THAN ECMWF AND OPERATIONAL GFS RUN. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 320 PM CDT SAT AUG 14 2004 .DISCUSSION... THE RELATIVELY COOL TEMPERATURES ALOFT OVER THE PAST FEW DAYS WILL SHIFT EAST OF THE AREA TONIGHT. WEAK LOW TO MID LEVEL WARM ADVECTION OVERNIGHT AND EARLY SUNDAY IS EXPECTED TO RESULT IN PLEASANT WEATHER. THE SIGNIFICANT WEATHER FEATURE IS THE UPPER LEVEL TROUGH SCHEDULED TO APPROACH WEST CENTRAL MINNESOTA LATE SUNDAY. SATELLITE IMAGERY SHOWS THIS TROUGH CURRENTLY ABOUT 57 DEGREES NORTH AND 112 DEGREES WEST. THE RUC MODEL SHOWS MUCH LOWER TROP HEIGHTS WITH THIS FEATURE THAN THE LONGER RANGE ETA OR GFS MODELS DO. SUSPECT IT WILL BE STRONGER THAN ANTICIPATED. THE GFS SHOWS THE BEST LIFT AND MID LEVEL FORCING ACROSS WEST CENTRAL MINNESOTA ABOUT MIDNIGHT...SUNDAY NIGHT BUT THE INSTABILITY IS FORECAST TO BE MARGINAL AT THIS TIME. THE STRONGEST INSTABILITY IS FORECAST BY THE ETA MODEL MONDAY AFTERNOON ACROSS WEST CENTRAL WISCONSIN. THINK THERE WILL BE TWO CONVECTIVE EVENTS TO FOCUS ON. ONE ERUPTING SUNDAY NIGHT ACROSS CENTRAL MINNESOTA. THE SECOND MONDAY AFTERNOON ALONG AND JUST AHEAD OF THE SURFACE FRONT THAT IS FORECAST TO ACCOMPANY THE UPPER LEVEL TROUGH. LONGER TERM...TUE NGT THRU SAT... LATEST...14/00Z...GFS RUN AS WELL AS 12Z RUN CONTINUES TO SLOW DOWN THE COLD FRNT MOVING THROUGH OUR CWA IN THE WED/THU PD. THUS...HAVE UPPED TEMPS SOMEWHAT AND DELAYED ONSET OF PRECIP ABOUT 12 HOURS. && MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ mn