AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 334 PM CDT THU AUG 12 2004 SC PREDOMINATING AGN TDA AS UNUSUALLY COOL AMS FOR AUG REMAINS IN PLACE. WK ISOLD LGT SHWRS THAT WERE ASSOC WITH A NICE VORT CIRC OVR FAR WC AND SW IA ERLY TDA HAVE DSIPTD. HOWEVER...WITH MAX HEATING THERE SVRL LGT SHWRS OVR THE FAR W. DO NOT SEE ANY REASON WHY TMR WILL NOT BE LIKE TDA. CLDS WITH ISOLD LGT SHWRS. HAVE THE SML POP FOR TMR BASED ON THE SVRL RUNS OF THE 13KM RUC...PRIMARILY FOR TMR AFTN. OTTHER THAN THAT...DID NOT REALLY CHG MUCH FM THE PREV FCST. TWEAKED TMPS DOWN A DEG OR PSBLY TWO DEGS DAY 2/3 BFR SUBSTANTIALLY WRMG ON SUNDAY. TIMING ON THE NXT S/W TO PRODUCE PCPN IS STARTING TO BOUNCE ARND...BUT STILL LOOKING LIKE SUN NGT INTO LATE MONDAY. NXT CDFNT ARRIVING MID WEEK AS ALRDY FCST WITH RE-ENFORCNG COOL AMS. WE MAYBE A BIT WARM FOR MAXES ON DAY6/7 BY 3-4 DEG IN THE N...BUT CAN ADJ AS THOSE PDS GET CLOSER. LOOKING WELL OUT NXT 10 DAYS...DO NOT SEE ANY BIG WARMUPS. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ MYERS ia AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE WICHITA KS 1125 AM CDT THU AUG 12 2004 .DISCUSSION... MAIN CONCERN WITH THIS AFTERNOON IS THE POTENTIAL FOR MORE CONVECTION. LATEST VISIBLE IMAGE SHOWING POSSIBLY ANOTHER BAND OF CONVECTION DEVELOPING ALONG AND NEWTON TO WICHITA TO WINFIELD LINE. THIS BAND OF CONVECTION APPEARS LIKE CONVECTIVE SYMMETRIC INSTABILITY (CSI). AFTER LOOKING AT THE ETA/RUC CROSS SECTIONS THERE IS SOME INDICATIONS OF THIS. IN ADDITION, THERE IS SOME GOOD THETAE ADVECTION TAKING PLACE BETWEEN 925-850MB WHICH IS HELPING PROVIDE DECENT LIFT INTO THE MID LEVEL COLD POCKET WHICH CONTINUES TO SLIDE SOUTHEAST FROM NORTHEAST KANSAS. MODELS PROJECT THAT WE MAY SEE WIDELY SCATTERED UPRIGHT CONVECTION THIS AFTERNOON MAINLY EAST OF THE TURNPIKE, BUT WITH DECENT DOWNGLIDE TAKING PLACE THE ACTIVITY WILL MOST LIKELY BE FEW AND FAR BETWEEN. WE WILL TWEAK POPS AND TAKE THEM OUT OF THE WEST. REST OF THE CWFA LOOKS GOOD. WE ALSO TWEAKED TEMPERATURES UP A LITTLE IN THE WEST. COX -------------------------------------------------------------------- 705 AM CDT THU AUG 12 2004 .DISCUSSION... TODAY: BROAD 500-MB VORT LOBE RACING SE OVER ERN NEBRASKA & NE KS & ASSOC'D COLD ADVCTN VCNTY THIS LVL SPARKED RPD DVLPMT OF SHRA OVER MOST OF SC KS ~630AM. UPDATING ALL ZONES (MORE SO SC & SE KS) TO PRESS HARDER ON POP THROTTLE (TO 30-40%) W/ THE SLGTLY HIGHER POP ASSIGNED TO SE KS WHERE 500-MB COLD ADVCTN STGR. EXTENSIVE M7 AC/M8 AC FLOCCUS COUPLED W/ ONSET OF NLY LWR-LVL COMP DICTATES LOWERING MAXES ALL AREAS TO ~75F W/ SE KS ON COOLER SIDE OF FENCE WHERE THICKER AC DECK PICTURED. ES --------------------------------------------------------------------- -- .PREV DISCUSSION... FCST CONCERNS... SLGT PCPN CHCS TODAY AND FRI... ENERGETIC SHRTWV UPR TROF WL CONT TO DIG SSEWD ACRS THE MO RVR VLY TODAY. MID LVL CAA AND ASSOCD COLD POOL MSTR WL MOV SEWD ACRS ERN KS, WITH MODELS SHOWG SQUATTY SLIVER OF CAPE BLO H5 DURG THE AFTN ACRS ERN PTNS OF THE CWA. WL KEEP SLGT POPS ACRS PTNS OF FLINT HILLS AND SERN KS THIS AFTN, THOUGH PCPN PROBLY MORE ISOLD FURTHER W INTO CNTRL KS AND WL WORD ACCORDINGLY. MAX TEMPS GENLY IN THE 75 TO 80F RANGE LOOK GOOD ACRS THE AREA. FAIR AND COOL WX AGAIN TNGT WITH A FEW RECORD MINS POSBL. SOME SEMBLENCE OF THE MID LVL THERMAL TROF WL RMN ACRS THE AREA INTO FRI ACRS SERN KS, THOUGH UPR DYNAMICS NOT AS FAVORABLE. THEREFORE WL JUST GO WITH ISOLD MENTION THERE IN THE AFTN. MEAN LNGWV UPR TROF WL RMN ANCHORED ACRS THE GRTLKS INTO THE MID MS VLY INTO THE WEEKEND. THIS SHOULD ONLY ALLOW FOR A GRADUAL MODERATING TREND WITH TEMPS RMNG BLO SEASONAL CLIMO. HAVE MADE SLGT DOWN TWEAK TO MAXS SAT/SUNDAY TO ACCOUNT FOR THIS SCENARIO. DARMOFAL && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 79 55 79 56 / 15 5 10 5 HUTCHINSON 79 53 79 54 / 15 5 10 5 NEWTON 78 54 78 55 / 15 5 10 5 ELDORADO 78 54 78 55 / 20 5 10 5 WINFIELD-KWLD 80 54 80 55 / 15 5 10 5 RUSSELL 77 51 77 52 / 10 5 10 5 GREAT BEND 77 51 77 52 / 10 5 10 5 SALINA 79 53 79 54 / 15 5 10 5 MCPHERSON 78 53 78 54 / 15 5 10 5 COFFEYVILLE 76 53 77 54 / 15 5 15 5 CHANUTE 76 52 77 53 / 20 5 15 5 IOLA 75 52 77 53 / 20 5 15 5 && .ICT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 13/DARMOFAL ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 400 PM EDT THU AUG 12 2004 .SHORT TERM...SFC TROF CONTINUES TO SLIP THROUGH THE SE HALF OF THE CWA, NOW LOCATED FROM AROUND HARRISVILLE SE TO BIG RAPIDS, WITH SFC WINDS SHIFTING SHARPLY TO THE NORTH BEHIND THE TROF. WATER VAPOR IMAGERY SHOWING THE SAME, WITH THE SHARP LOW-MID LEVEL TROF/DEFORMATION AXIS STRETCHING DOWN THROUGH LOWER MICHIGAN. KAPX RADAR CONTINUES TO SHOW A BAND OF LIGHT TO OCCASIONALLY MODERATE SHOWERS/DRIZZLE WITHIN THE TROF AXIS FROM ALPENA COUNTY DOWN THROUGH BIG RAPIDS AIDED BY UPSLOPE FLOW AND DAYTIME HEATING AND SOME LAKE HURON CONTRIBUTION. ALSO OF NOTE, MESOSCALE VORTEX THAT CAME ONSHORE THROUGH GRAND TRAVERSE BAY EARLIER THIS MORNING NOW WORKING ITS WAY SOUTH OUT OF MISSAUKEE COUNTY AND HAS PROMOTED A LITTLE BETTER COVERAGE OF SHOWERS OVER THE SW COUNTIES THROUGHOUT THE DAY. MEANWHILE, NORTH FLOW LAKE EFFECT BANDS OVER NRN LAKE MICHIGAN HAVE BECOME FAIRLY DISRUPTED THIS AFTERNOON, BUT STILL SEEING SOME HINTS OF BANDING ON RADAR FROM BEAVER ISLAND DOWN ACROSS THE LEELANAU PENINSULA AND INTO MANISTEE. FOR TONIGHT...FORECAST ISSUES CONTINUE TO FOCUS ON PRECIP CHANCES WITH THE MESOSCALE FEATURE AND TROF AXIS SLIPPING THROUGH THE SOUTHERN COUNTIES EARLY THIS EVENING. THEN...ANY ADDITIONAL LAKE EFFECT SHOWERS REORGANIZING OVERNIGHT. THIS EVENING...SFC TROF WILL SLIP INTO THE SAGINAW VALLEY EARLY THIS EVENING WITH THE MESOSCALE CIRCULATION FOLLOWING SUITE INTO CENTRAL LOWER MICHIGAN. WITH LINGERING 700-500MB Q-VECTOR CONVERGENCE (COURTESY OF DEFORMATION FLOW DYNAMICS), COMBINED WITH A HUNDRED OR SO JOULES OF CAPE OVER THE SE COUNTIES PER LAPS ANALYSIS AND LOW LEVEL CONVERGENCE WITH THE SFC TROF AND MESOSCALE VORTEX, WILL NEED TO KEEP ISOLATED-SCATTERED SHOWERS GOING INTO THE EARLY EVENING FOR AREAS BASICALLY SOUTH OF M-68. A DRY FORECAST LOOKS GOOD FOR AREAS NORTH. THEN, WITH LOSS OF DAYTIME HEATING AND AFTER THE TROF/MESOSCALE FEATURE MOVES SOUTH, WILL HAVE A DRY FORECAST FOR MUCH OF EASTERN UPPER AND NW/NORTH CENTRAL LOWER MICHIGAN AFTER 02Z OR SO AND SOME DECREASE IN THE CLOUD COVER. AS LAKE EFFECT PRECIP IS CONCERNED...ENOUGH OVER LAKE INSTABILITY REMAINS OVERNIGHT TO SUPPORT LAKE EFFECT SHOWERS REORGANIZING OVER LAKE MICHIGAN AND LAKE HURON. MESOETA/RUC BOTH SUGGESTING A MID LAKE CONVERGENCE BAND SETTING UP DOWN THROUGH LAKE MICHIGAN, BUT WITH DEVELOPING LAND BREEZES THIS SHOULD REMAIN OFFSHORE UNTIL MORNING. ON THE LAKE HURON SIDE HOWEVER, LOW LEVEL FLOW FORECAST TO VEER TO THE NE AND WILL LIKELY BEGIN TO BRING SOME LIGHT RAIN SHOWERS INTO PORTIONS OF NE LOWER MI, PRIMARILY SOUTH OF M-32 AND EAST OF M-33. SO WILL CONTINUE WITH A CHANCE FOR SHOWERS IN THIS AREA AS WELL AS ISOLATED SHOWERS ALONG THE LAKE HURON SHORELINE FROM APN TO THE BRIDGE. ADAM .LONG TERM...FORECAST CONCERNS DEAL WITH PERSISTENT UPPER TROUGH AND LAKE EFFECT...RESULTING SHOWER CHANCES THROUGH FRIDAY EVENING. TEMPS A CONCERN AS WELL...WITH LOWS IN SOME OF THE TYPICALLY COOL LOCATIONS SEEING CHILLY MORNING TEMPS FOR FRIDAY NIGHT AND SATURDAY NIGHT. RECORDS DO NOT SEEM IN JEOPARDY ATTM. TONIGHT AND FRIDAY...ETA/GFS ARE SIMILAR IN HOLDING 500 MB TROUGH OVER REGION THROUGH FRIDAY. MODELS SHOW TWO SHORT WAVE TROUGHS OF INTEREST MOVING AROUND PERIPHERY OF UPPER TROUGH. THE FIRST WILL DROP SOUTH THROUGH MN TONIGHT...REACHING IA BY MIDDAY FRIDAY. THIS SHORT WAVE WILL ACT TO SUPPRESS 500 MB HEIGHTS SLIGHTLY ON BACK SIDE OF TROUGH...AND EFFECTIVELY SLOW EWD MOVEMENT OF UPPER TROUGH. THE SECOND SHORT WAVE WILL LIFT NE THROUGH THE OHIO VALLEY TONIGHT... REACHING THE ERN GREAT LAKES FRIDAY. FEATURE WILL PROVIDE MODEST 850-500 MB QG FORCING OVER NRN LOWER LATE TONIGHT AND FRIDAY. SHORT WAVE MAY ULTIMATELY BE FURTHER ENHANCED BY REMNANTS OF TROPICAL STORM BONNIE...AS IT LIFTS RAPIDLY NE ALONG THE ERN SEABOARD. WILL KEEP SLIGHT RISK OF SHOWERS IN FORECAST TONIGHT FOR ALL OF NRN LOWER. 500 MB SHEAR/DEFORMATION AXIS REMAINS OVERHEAD...AND SHOULD SUPPORT WEAK FORCING FOR ASCENT. NE FLOW ACROSS LAKE HURON (WITH 850 MB TEMPERATURES AROUND +5C AND DELTA T/S NEAR 15C) MAY ALSO SUPPORT A FEW LAKE INDUCED SHOWERS E OF I-75. MODEL SOUNDINGS INDICATE ONLY SHALLOW MOISTURE (WARMER THAN ABOUT -3C) SO ANY SHOWERS THAT OCCUR SHOULD BE LIGHT AND WIDELY SCATTERED. PROXIMITY OF 500 MB LOW/TROUGH...TOGETHER WITH PREVIOUSLY MENTIONED QG SUPPORT...AND PERSISTENT MOISTURE IN 850-700 MB LAYER (80-90%) WILL SUPPORT A CONTINUED RISK FOR SHOWERS ON FRIDAY. AUGUST SUN... COUPLED WITH VERY MODEST DIFFERENTIAL TEMPERATURE ADVECTION...WILL LIKELY RESULT IN SOME DIURNAL COMPONENT TO THE SHOWERS (DISRUPTING LAKE CONTRIBUTIONS). MODEL SOUNDINGS SUPPORT AROUND 200 J/KG CAPE. WILL CONSEQUENTLY INCLUDE RISK FOR SHOWERS ALL AREAS EXCEPT FOR ERN UPPER...WHERE CAPES ARE A BIT LOWER. FRIDAY AND FRIDAY EVENING...H5 TROUGH HOLDING ON OVER NRN MICHIGAN AND SHOWING LITTLE EAST MOVEMENT FROM THURSDAY NIGHT...ALTHOUGH BASE OF THE TROUGH WILL BEGIN TO LIFT NE THROUGH THE EVENING. THE DEFORMATION/CONVERGENCE BETWEEN H7-H5 WEAKENS THROUGH THE DAY AS WELL WITH ONLY MEAGER Q VECTOR CONVERGENCE CLINGING TO LAKE HURON SHORE. THUS...SYNOPTIC FORCING LESS THAN SEEN THURSDAY. AS FAR AS THE LAKES ARE CONCERNED...H8 TEMPS ONLY WARM FROM NEAR 4C TO 6C BY LATE AFTERNOON RESULTING IN DELTA T'S OF 13C-16C IN THE MORNING TO 11C-14C BY AFTERNOON. SFC-H8 WIND FLOW IS LESS CYCLONIC AND OUT OF THE NE IN THE MORNING...BACKING NORTHERLY BY AFTERNOON. INVERSION HEIGHTS REMAINING AROUND 7.5 KFT BUT MOISTURE DECREASING THROUGH THE DAY FROM THE NORTH. WILL HAVE SCATTERED RAIN SHOWERS ALONG THE LAKE HURON SHORE IN THE MORNING...PARTICULARLY SOUTH WHERE FETCH IS GREATEST. BASE OF TROUGH SHOWING WEAK VORTICITY ROTATING AROUND SLIDING UP THROUGH THE SRN CWA FRIDAY. IN ADDITION...MESO-ETA WHICH PICKED UP ON THE MESOSCALE CIRCULATION THURSDAY...ALSO SHOWING SIMILAR SIGNS ACROSS AREAS SOUTH OF GRAND TRAVERSE BAY TOMORROW. WILL ULTIMATELY SHIFT THE LAKE EFFECT SHOWERS ALONG LAKE HURON AND OUT OVER LAKE MICHIGAN INLAND THROUGH MIDDAY...WHILE DEVELOPING SCATTERED SHOWERS WITH TROUGH AXIS IN THE AFTERNOON. THE DRIER AIR INFILTRATING IN FROM THE NORTH...WILL RESULT IN LOWERED CHANCES IN THE AFTERNOON FOR THE NRN MITT. WITH THE FLOW OUT OF THE NORTH IN THE EVENING...AS WELL AS H8 TEMPS REMAINING AROUND 6C IN THE EVENING...CAN SEE SOME LAKE EFFECT SHOWERS (ISOLATED) AFFECTING THE THE NORTHERLY FLOW AREAS...AND FAR SRN CWA BEFORE LOSS OF DAYTIME HEATING/LAND BREEZE DEVELOPMENT PUSHING SHOWERS OUT OVER MID LAKE. UNFAVORABLE FETCH AND DRIER AIR RESULTING IN DRY CONDITIONS FOR EASTERN UPPER THROUGH THIS TIME. FRIDAY NIGHT THROUGH SATURDAY NIGHT...WEAK SHORTWAVE TROUGH SLIDES ACROSS NRN MICHIGAN FOR THE REMAINDER OF FRIDAY NIGHT. DRYING AIR MASS AND LOSS OF HEATING PROBABLY KEEPING ANY SHOWERS FROM MAINTAINING THROUGH THE NIGHT. PLUS...SFC-H8 FLOW BECOMES ANTICYCLONIC BY MORNING. WILL KEEP THINGS DRY THROUGH THEN. SHOULD ALSO BE MORE POCKETS OF CLEARING WITH LESS ATMOSPHERIC MOISTURE. SOME FAIRLY COLD SPOTS ARE POSSIBLE WITH TEMPS INTO THE LOWER 40S. HAVE ADJUSTED LOW TEMP GRIDS ACCORDINGLY. SATURDAY...SFC HIGH PRESSURE FINALLY BUILDS IN FROM THE WEST WITH UPPER TROUGH AXIS SHIFTING EAST. MORE SUNSHINE EXPECTED...AND FORECAST COULD BE PUSHED MORE TOWARD A SUNNIER CONDITION...BUT ATTM...WILL KEEP HALF THE SKY IN SHALLOW CUMULUS. OVERALL ATMOSPHERIC MOISTURE DECREASES FURTHER SATURDAY NIGHT UNDER INCREASING SUBSIDENCE. RADIATIONAL COOLING SHOULD BE DECENT THIS NIGHT WITH THE LOW LYING/TYPICALLY COOL AREAS SEEING LOWS IN THE LOWER 40S. SUNDAY...EXPECT DRY CONTINUES TO CONTINUE WITH SFC HIGH PRESSURE REMAINING IN CONTROL. WARMER TEMPS EXPECTED IN THE SOUTHERLY RETURN FLOW WHICH DEVELOPS LATER IN THE DAY...AS WELL AS FROM DIURNAL HEATING...OF WHAT MAY END UP BEING THE MOST SUN WE SEE THROUGH NEXT WEEK. THE UPPER TROUGH AXIS THAT REFUSES TO MOVE EAST WILL FINALLY DO JUST THAT/OR AT LEAST WE GET SOME MINOR RIDGING IN THE MID LEVELS. MID TO UPPER 70S LOOKS GOOD HERE...WITH A PARTY SUNNY SKY. SOME HIGHER CLOUD MAY BE ROLLING ACROSS EASTERN UPPER AS NEXT UPSTREAM SHORTWAVE ROUNDING THE GENERAL TROUGH WHICH CONTINUES TO ENGULF MUCH OF THE EASTERN CONUS. EXTENDED...(MONDAY THROUGH THURSDAY)...MODELS ACTUALLY IN DECENT AGREEMENT HERE...AND MORE CONSISTENT WITH YESTERDAYS RUNS. STILL LOOKING LIKE SHORTWAVE TROUGH (NEXT UPSTREAM SHORTWAVE IN PREVIOUS PARAGRAPH) MOVES INTO NRN MICHIGAN MONDAY NIGHT (THIS IS A BIT SLOWER...WHICH WAS ORIGINALLY THOUGHT)...SO WILL HOLD BACK ON INITIAL PRECIP CHANCES FOR ALL BUT THE WESTERN CWA UNTIL MONDAY NIGHT. THIS SHORTWAVE MAKES SLOW PROGRESS WESTWARD...AND ALTHOUGH TUESDAY MAY BE A RELATIVELY QUIET DAY...CANNOT SEE TAKING ANY PRECIP CHANCE OUT AT THIS POINT...ESPECIALLY WITH THIS BEING DAY 6 AND THERE WILL LIKELY BE MORE TIMING ISSUES. SFC REFLECTION STILL WEAK AT BEST...AND WILL ONLY KEEP 30 POPS IN (AS CURRENT FORECAST SHOWS). THE BEST SHOT WILL BE WITH SECOND/MAIN UPPER TROUGH THAT DROPS INTO THE GREAT LAKES WEDNESDAY/WEDNESDAY NIGHT. GFS SLOWER/ECMWF FASTER WITH THIS FEATURE...AND AM MORE INCLINED TO SIDE WITH THE SLOWER SOLUTION BASED OFF RECENT EXTENDED MODEL TRENDS AND MREF CONSENSUS. THEREFORE...WILL JUST SHOW 40 POPS (LARGE AS I WISH TO GO...WHILE STILL SHOWING A BETTER CHANCE) WEDNESDAY AND WEDNESDAY NIGHT. THIS SYSTEM LOOKING LIKE H8 TEMPS DROPPING INTO ANOTHER ATYPICAL AUGUST COOL SPELL WITH READINGS DOWN INTO 0-1C ACROSS EASTERN UPPER. WILL GO AHEAD AND DROP TEMP FORECAST DOWN INTO AT LEAST THE UPPER 60S TO LOWER 70S SE. BY FRIDAY...COULD BE LOOKING AT SOME AREAS HAVING TROUBLE REACHING THE 60S...BUT WILL HOLD OFF ON GOING THAT COLD FOR NOW. SMD && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1152 AM EDT THU AUG 12 2004 .UPDATE... CURRENT FORECAST BASICALLY ON TRACK. CU HAS QUICKLY FILLED IN ACROSS THE CWA THIS MORNING...IN ADDITION TO CLOUDS/MOISTURE ACROSS THE SOUTHERN CWA. BETTER LOW-LEVEL MOISTURE NEAR DEFORMATION AXIS ACROSS SOUTHERN LOWER...WITH ADDITIONAL FLUX FROM LAKE MICHIGAN. CU SOMEWHAT THIN ACROSS THE THUMB...BUT WITH DECENT LOW-LEVEL LAPSE RATES NEAR 850MB THERMAL TROUGH THE CLOUDS SHOULD THICKEN ENOUGH TO WARRANT MOSTLY CLOUDY ACROSS THE BOARD. REGIONAL RADARS SHOW SCATTERED REFLECTIVITIES WORKING INTO THE SOUTHWESTERN CWA...SOME LAKE ENHANCEMENT FROM SOUTHERN LAKE MICHIGAN AS WELL AS SOME SYNOPTIC LIFT UNDER DEFORMATION. 12Z DTX SOUNDING/12Z RUC FORECAST SOUNDINGS SUPPORT ENOUGH LOW-LEVEL INSTABILITY/LAPSE RATES BELOW CAP TO SEE SOME SHOWERS. NOT QUITE AS MOIST AS YESTERDAY...BUT SHOULD STILL BE ENOUGH DIURNAL INSTABILITY TO KEEP SCATTERED SHOWERS GOING. BASED OFF RADAR/SATELLITE TRENDS OF BETTER MOISTURE/THICKER CLOUDS AND SHOWERS IN THE SOUTH...WILL ADJUST POPS TO FEATURE HIGHEST IN THE SOUTHWEST CWA. GIVEN ADDITIONAL CLOUD COVER IN THE SOUTH AS WELL...WILL TRIM BACK HIGHS A COUPLE DEGREES AS WELL...GENERALLY MID-UPPER 60S ACROSS THE CWA. && BRAVENDER .PREV DISCUSSION...320 AM EDT THU AUG 12 2004 MODELS IN GENERAL AGREEMENT OVER THE GREAT LAKES. MODELS HAVE SOME ISSUES WITH THE TROPICAL SYSTEMS...BUT SHOULD ONLY HAVE A MINOR IMPACT ON SE MI FORECAST. JUST SOME LAKE SHOWERS ACROSS THE WESTERN PORTION OF LOWER MICHIGAN. RADAR MOSAICS DO SUGGEST SOME SORT OF SHORTWAVE ROTATING FROM UPPER MI INTO LAKE MI. MODELS ALSO HAVE THIS FEATURE. THE DEEPER MOISTURE ASSOCIATED WITH THE OLD DEFORMATION AXIS WAS ROUGHLY ALIGNED WITH THE SHORTWAVE. THIS IS ALL FORECAST TO PUSH MOSTLY SOUTH AND SLIGHTLY EAST THROUGH THE DAY. THUS ONLY THE NORTHWESTERN END OF CWA WILL GET INTO THE GOOD AND DEEP MOISTURE. WITH THAT SAID...MODEL SOUNDINGS DO INDICATE GOOD LOW LEVEL INSTABILITY WITH AN INVERSION AROUND 700 MB. PARCELS SHOULD BE ABLE TO SUFFICIENTLY PASS THE INVERSION WITH FORECAST HIGHS AND DEW POINTS AS PARCEL AND AIR TEMP WILL BE NEARLY THE SAME ABOVE THE INVERSION. WILL THEREFORE KEEP THE CHANCE OF SHOWERS...BUT WILL NOT ADD ANY THUNDER. WILL LOWER POPS TO 20 PCT ACROSS FAR SOUTHEAST LOWER GIVEN THAT THEY WILL BE FARTHER FROM THE SHORTWAVE AND DEEPER MOISTURE. WILL GO WITH THE WARMER MOS NUMBERS SINCE THERE WILL BE BREAKS IN THE CLOUDS TO GIVE ENOUGH SUN TO WARM AT LEAST THAT MUCH. BY FRIDAY...BONNIE MOVES UP THE EASTERN SEABOARD AND A STRONG SHORTWAVE DIVES WELL SOUTH OF MI IN THE BASE OF THE 500 MB TROF. HOWEVER THESE TWO SYSTEMS INTERACT WITH EACH OTHER...THE EFFECTS FOR LOWER MICHIGAN WILL BE TO HOLD THE 500 MB TROF OVERHEAD AND TURN THE SURFACE FLOW MORE TO THE NORTH AND NORTHEAST. MODELS INDICATE SOME CYCLONIC FLOW AT THE SURFACE AS WELL ON FRIDAY. WITH 850 TEMPS STILL +6 TO +7 THIS WILL AID THE SHOWERS ACROSS THE THUMB AND TRI CITIES FROM THE FLOW OFF OF LAKE HURON. OTHERWISE...MODEL SOUNDINGS LOOK REMARKABLY SIMILAR FOR FRIDAY AS TODAY...SO WILL KEEP THE SAME POPS...20 PCT IN FAR SE LWR AND 30 TO 40 TO THE FAR NORTH. AGAIN ENOUGH BREAKS IN THE CLOUDS...ESPECIALLY IN FAR SOUTHEAST LOWER TO GO WITH THE WARMEST MOS NUMBERS ON FRIDAY. EVEN WITH THE LONG WAVE 500 MB TROF HANGING OVER LOWER MICHIGAN FRIDAY NIGHT AND SATURDAY AND A WEAK SHORTWAVE IN THAT UPPER FLOW...WILL KEEP FORECAST DRY. DRYING AT 700 MB AND BELOW WILL CONTINUE TO SLOWLY OCCUR DURING THAT TIME...AND WEAK LOW LEVEL FLOW WILL NOT PROVIDE ANY GOOD CONVERGENCE TO GET ANYTHING GOING. MARINE... CONVECTIVE INSTABILITY OVER THE WATER CONTINUES TO BE EVIDENT. THESE OBSERVATIONS SUPPORT A CONTINUED MENTION OF WATERSPOUTS IN OUR MARINE FORECASTS. THE BEST CHANCE OF SPOUTS WILL BE OVER THE WATERS OF LAKE HURON AND ON SAGINAW BAY THIS MORNING. THE SURFACE TROF WILL HELP FOCUS CONVERGENCE OVER NORTHERN LAKE HURON. THE LAND BREEZE COMPONENT OF THE SW FLOW ON SAGINAW BAY WILL HELP WITH LOW LEVEL CONVERGENCE THERE AS OVERWATER INSTABILITY CONTINUES IN THE 15 TO 20C RANGE FROM THE LAKE TO 850 MB. CONVECTIVE CLOUD DEPTH HAS DIMINISH A BIT BUT IT SHOULD BE ENOUGH TO SUPPORT ADEQUATE UPDRAFTS. THE GRADIENT WILL CONTINUE TO WEAKEN WITH LAKE TO 850 MB TEMPERATURE DIFFERENCES AROUND 15C. THEREFORE WILL ADD SPOUTS TO SOUTHERN LAKE HURON AND LAKE ERIE FRIDAY MORNING...AND THEN JUST LAKE ERIE ON SATURDAY MORNING. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && RBP $$ EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1100 AM EDT THU AUG 12 2004 .DISCUSSION... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW HIGHLY AMPLIFIED PATTERN OVER CONUS WITH RIDGE OVER THE W AND A DEEP TROF EXTENDING S THRU THE GREAT LAKES. DRIER AIR AND SUBSIDENCE (SHARP SUBSIDENCE INVERSION NOTED ON 12Z KINL SOUNDING AT ABOUT 700MB) ARRIVING BEHIND SHORTWAVE MOVING E OF THE GREAT LAKES HAS BROUGHT IMPROVED CONDITIONS TO UPPER MI THIS MORNING. UPSTREAM...A WEAK SHORTWAVE WAS DROPPING S TOWARD FAR NW ONTARIO AND IS ACCOMPANIED BY A BAND OF CLOUDS THAT IS APPROACHING CYPL. THIS SYSTEM WILL NOT BE A FACTOR IN THE WEATHER HERE TODAY. SOLAR HEATING AND LINGERING BOUNDARY LAYER MOISTURE HAS ALREADY YIELDED RAPID CU DEVELOPMENT THIS MORNING... ESPECIALLY OVER THE E HALF OF UPPER MI. GOING FCST LOOKS TO BE IN GOOD SHAPE FOR THE AFTN. AFTER DECENT CU DEVELOPMENT THIS MORNING...EXPECT CONTINUED WEAK ADVECTION OF DRIER AIR AS WELL AS DOWNWARD MIXING OF DRIER AIR FROM ALOFT (PER 12Z CWPL SOUNDING) TO LEAD TO SOME DISSIPATION OF CU DURING THE COURSE OF THE AFTN. WRN FCST AREA IS MORE FIRMLY INTO THE DRIER AIR...SO LEAST CLOUD COVER WILL BE THERE. AS FOR TEMPS...12Z SOUNDINGS SUPPORT HIGHS GENERALLY IN THE MID 60S. TEMPS WILL BE A FEW DEGREES COOLER NEAR LAKE SUPERIOR WITH ONSHORE FLOW. UPDATED GRIDS ALREADY SENT. && .PREV DISCUSSION... THOUGH COLD AIR ALOFT LINGERS OVER THE AREA THROUGH FRIDAY (AND IS IN FACT REINFORCED BY A SHORTWAVE DROPPING WEST OF US TNGT)... APPEARS AS IF THE AMS WILL REMAIN TOO DRY FOR ANY DIURNAL SHRA. K- INDICES ON FRI ARE ONLY IN THE TEENS...AND SFC DEWPTS WILL BE IN THE LOWER 40S. AGAIN...LOOKS LIKE JUST AN AFTN CU DAY. REGARDING TEMPS...WILL SEE A SLOW MODERATION OVER THE NEXT COUPLE DAYS AS NLY FLOW WILL CONTINUE. 850MB TEMPS RISE TO AROUND 5C TODAY AND 7C FRIDAY. NEAR GUIDANCE FOR HIGHS SHOULD SUFFICE...60S TODAY AND MID 60S/AROUND 70 FRIDAY. WILL BE MUCH WARMER THAN WEDNESDAY BUT STILL BELOW NORMAL FOR MID AUGUST. A PERSISTENT NLY FLOW WILL KEEP TEMPS FROM FALLING OFF TOO FAR TONIGHT...BUT MAY STILL SEE NEAR 40F OVER THE WESTERN HIGHER TERRAIN UNDER CLEARING SKIES. HAVE GONE BELOW GUIDANCE FRI NIGHT AS SFC RIDGE FINALLY BUILDS OVHD AND ALLOWS FOR WINDS TO DECOUPLE. SHOULD AGAIN SEE INLAND LOWS INTO THE LOWER 40S...POSSIBLY COOLER IF SKIES ARE CLEAR (MODELS DO HINT AT SOME MID LEVEL HIGHER RH SPREADING IN OVERNIGHT FROM THE NW...COURTESY OF SOME ISENTROPIC LIFT...SO HAVE NOT GONE TOO COLD). TEMPS ON SAT SHOULD RETURN TO NEAR NORMAL (70S)...BUT EVEN THEN A WEAK SLY FLOW SHOULD ALLOW FOR LAKE SUPERIOR BREEZES TO DEVELOP. MODELS ARE TRENDING A BIT FAST WITH NEXT WEATHER MAKER CURRENTLY FORECAST TO ARRIVE SUN NIGHT/MON. THE 00Z ETA IS QUITE A BIT FASTER AND IS AN OUTLIER...WITH THE SLOWER GFS BEING MORE CONSISTENT (BRINGING PCPN INTO THE U P SUN NIGHT)...SO HAVE MADE NO CHANGES IN THE GRIDS FOR NOW. FASTER TIMING MAY NOT BE UNREASONABLE THOUGH AS BONNIE SHOULD SLOW THE EASTWARD MOVEMENT OF THE GREAT LAKES TROF... AND POSSIBLY ALLOW FOR NEXT SHORTWAVE TO DIG A BIT FASTER. AFTER ALL...THIS IS THE STORY OF OUR SUMMER. WILL LET DAY SHIFT TAKE A CLOSER LOOK. COORDINATED WITH APX/DLH/GRB...THANKS. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON (DISCUSSION) JKL (PREV DISCUSSION) mi AREA FORECAST DISCUSSION...UPDATED SHORT TERM NATIONAL WEATHER SERVICE WILMINGTON OH 1015 AM EDT THU AUG 12 2004 .SHORT TERM (THIS AFT)... SURFACE ANALYSIS SHOWS WEAK SURFACE RIDGE ACROSS THE OHIO VALLEY WITH TROFS OF LOW PRESSURE OVER THE GREAT LAKES AND FROM THE GULF OF MEXICO INTO THE MID ATLANTIC STATES. SATELLITE IMAGERY SHOWS WESTERN EDGE OF CLOUD DECK IN FAR SOUTHEASTERN FA WITH CLEAR SKIES ACROSS THE REST OF FA. CLOUDS EXPECTED TO DEVELOP QUICKLY THROUGH LATE MORNING AND BE MO CLOUDY THIS PM. WILL UPDATE SHORTLY TO GET RIDE OF MORNING WORDING. WILL WATCH HOW THINGS DEVELOP AND MAKE A GAME TIME DECISION IN THE TRI-STATE ON WHETHER TO LEAVE PC OR GO MO CLOUDY. CURRENT AFT TEMPS LOOK GOOD. UPDATED EARLIER TO TAKE OUT THE MENTION OF PRECIP IN THE EAST. && PREVIOUS DISCUSSION... AVIATION (12Z-12Z)... REMAINING LIFT IN FAR SERN FA WILL KEEP SOME LINGERING SHRA MAINLY THIS MORNING. THIS SHOULD REMAIN E OF KCMH THOUGH. AS FOR CLOUDS TODAY...EXPECT ONLY FEW MID CLOUDS TO SKY CLEAR UNTIL ABOUT 15Z FOR KDAY/KCVG/KILN/KDAY BEFORE COLD AIR CU DEVELOPS. POSSIBILITY OF SIGNIFICANT BREAKS TO POSSIBLY EVEN SCT TOWARD SUNSET BEFORE ANOTHER MID DECK SWINGS THROUGH WITH SOME WRAP AROUND DOWN THE TROF. KCMH WILL BE STATION WITH LEAST CHANCE FOR SIGNIFICANT CLEARING...WITH CURRENT SITUATION ON BACK EDGE OF AC DECK...FOLLOWED BY DIRUNAL CU TODAY AND THEN PULLING UP MOISTURE ASSOCIATED WITH BONNIE AND A S/WV SWINGING THROUGH BOTTOM OF DEEP TROF FOR FRIDAY. && SHORT TERM(TODAY THROUGH SATURDAY)... WATER VAPOR IMAGERY THIS MORNING...ALONG WITH RUC40...DEPICTED A S/WV ACRS SW OHIO INTO WRN KY. THIS FEATURE WAS RESPONSIBLE FOR THE MOSTLY CLOUDY CONDITIONS AND RAIN SHOWERS OVER THE ERN CWFA. THUS...FIRST FCST PROBLEM WILL BE THE RAIN SHOWERS ACRS THE ERN CWFA. WILL KEEP A 30 OR 40 POP IN THESE LOCATIONS THROUGH DAYBREAK...THEN DRY WX SHOULD PREVAIL ONCE THIS S/WV PASSES BY. OTHERWISE...OUR REGION WILL REMAIN UNDER THE INFLUENCE OF AN UNSEASONABLY COLD TROF FOR THIS TIME OF THE YEAR. SINCE THE UPR LEVEL PATTERN IS HIGHLY AMPLIFIED (H5 RIDGE WRN U. S. WITH H5 TROF ERN U. S.)...AND WITH THE TROPICAL SYSTEMS OF BONNIE AND CHARLEY...THIS TROF WILL NOT MOVE ALL THE MUCH THROUGH THE FIRST PART OF THE WEEKEND. THUS...BELOW NORMAL TEMPS WILL CONTINUE. AT THIS POINT IN TIME...THE ETA MODEL IS TRYING TO DEVELOP PCPN IN OUR FAR EASTERN CWFA LATE TONIGHT INTO FRIDAY MORNING. THIS IS THE RESULT OF A S/WV DROPPING THROUGH THE MEAN BASE OF THE UPR TROF...WHILE TRYING TO PULL IN SOME MSTR FROM THE REMNANTS OF BONNIE. THE GFS...ON THE OTHER HAND...KEEPS BONNIE'S MAIN MOISTURE EAST OF OUR AREA. WILL KEEP A DRY FCST AT THIS POINT SINCE THE ERN CWFA WILL BE ON THE FRINGE. THERE WILL BE PLENTY OF DIURNAL CUMULUS DEVELOPMENT TODAY INTO FRIDAY. BEST CHANCE FOR SUN TODAY WILL BE IN THE SWRN CWFA (CVG)...WHILE OTHER AREAS WILL REMAIN MOSTLY CLOUDY DUE TO CUMULUS CLOUDS (AND MID LVL MSTR STREAMING NORTHWARD ACRS FAR ERN CWFA). ON FRIDAY...AM EXPECTING MAINLY MOSTLY CLOUDY CONDITIONS AS COOLEST AIR WILL BE OVER HEAD AND TROF AXIS WILL BE OVERHEAD. FOR SATURDAY....SFC HIGH PRESSURE WILL GRADUALLY BUILD INTO THE REGION. SKIES SHOULD BECOME PARTLY CLOUDY WITH A WARMING TREND. WENT CLOSE TO MAV GUIDANCE FOR TEMPS AS IT SEEMS REASONABLE TO USE THROUGH SATURDAY. && LONG TERM (SATURDAY THROUGH WEDNESDAY)... THE FOLLOWING WAS ISSUED AT 323 PM EDT WED AUG 11 2004. NORTHWEST TO WEST FLOW ALOFT WILL KEEP WEATHER DRY THROUGH MOST OF FORECAST. TROF APPROACHING NEXT WEDNESDAY WILL REQUIRE CHANCE POPS. TEMPS WILL REMAIN BELOW AVERAGE THROUGH MONDAY. AS SURFACE HIGH MOVES EAST A SOUTHERLY FLOW WILL DEVELOP AND READINGS MAY WARM TO NEAR NORMAL BY NEXT WEDNESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. IN...NONE. KY...NONE. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 655 AM EDT THU AUG 12 2004 .AVIATION (12Z-12Z)... REMAINING LIFT IN FAR SERN FA WILL KEEP SOME LINGERING SHRA MAINLY THIS MORNING. THIS SHOULD REMAIN E OF KCMH THOUGH. AS FOR CLOUDS TODAY...EXPECT ONLY FEW MID CLOUDS TO SKY CLEAR UNTIL ABOUT 15Z FOR KDAY/KCVG/KILN/KDAY BEFORE COLD AIR CU DEVELOPS. POSSIBILITY OF SIGNIFICANT BREAKS TO POSSIBLY EVEN SCT TOWARD SUNSET BEFORE ANOTHER MID DECK SWINGS THROUGH WITH SOME WRAP AROUND DOWN THE TROF. KCMH WILL BE STATION WITH LEAST CHANCE FOR SIGNIFICANT CLEARING...WITH CURRENT SITUATION ON BACK EDGE OF AC DECK...FOLLOWED BY DIRUNAL CU TODAY AND THEN PULLING UP MOISTURE ASSOCIATED WITH BONNIE AND A S/WV SWINGING THROUGH BOTTOM OF DEEP TROF FOR FRIDAY. && PREVIOUS DISCUSSION...ISSUED 256 AM THU AUG 12 2004 SHORT TERM(TODAY THROUGH SATURDAY)... WATER VAPOR IMAGERY THIS MORNING...ALONG WITH RUC40...DEPICTED A S/WV ACRS SW OHIO INTO WRN KY. THIS FEATURE WAS RESPONSIBLE FOR THE MOSTLY CLOUDY CONDITIONS AND RAIN SHOWERS OVER THE ERN CWFA. THUS...FIRST FCST PROBLEM WILL BE THE RAIN SHOWERS ACRS THE ERN CWFA. WILL KEEP A 30 OR 40 POP IN THESE LOCATIONS THROUGH DAYBREAK...THEN DRY WX SHOULD PREVAIL ONCE THIS S/WV PASSES BY. OTHERWISE...OUR REGION WILL REMAIN UNDER THE INFLUENCE OF AN UNSEASONABLY COLD TROF FOR THIS TIME OF THE YEAR. SINCE THE UPR LEVEL PATTERN IS HIGHLY AMPLIFIED (H5 RIDGE WRN U. S. WITH H5 TROF ERN U. S.)...AND WITH THE TROPICAL SYSTEMS OF BONNIE AND CHARLEY...THIS TROF WILL NOT MOVE ALL THE MUCH THROUGH THE FIRST PART OF THE WEEKEND. THUS...BELOW NORMAL TEMPS WILL CONTINUE. AT THIS POINT IN TIME...THE ETA MODEL IS TRYING TO DEVELOP PCPN IN OUR FAR EASTERN CWFA LATE TONIGHT INTO FRIDAY MORNING. THIS IS THE RESULT OF A S/WV DROPPING THROUGH THE MEAN BASE OF THE UPR TROF...WHILE TRYING TO PULL IN SOME MSTR FROM THE REMNANTS OF BONNIE. THE GFS...ON THE OTHER HAND...KEEPS BONNIE'S MAIN MOISTURE EAST OF OUR AREA. WILL KEEP A DRY FCST AT THIS POINT SINCE THE ERN CWFA WILL BE ON THE FRINGE. THERE WILL BE PLENTY OF DIURNAL CUMULUS DEVELOPMENT TODAY INTO FRIDAY. BEST CHANCE FOR SUN TODAY WILL BE IN THE SWRN CWFA (CVG)...WHILE OTHER AREAS WILL REMAIN MOSTLY CLOUDY DUE TO CUMULUS CLOUDS (AND MID LVL MSTR STREAMING NORTHWARD ACRS FAR ERN CWFA). ON FRIDAY...AM EXPECTING MAINLY MOSTLY CLOUDY CONDITIONS AS COOLEST AIR WILL BE OVER HEAD AND TROF AXIS WILL BE OVERHEAD. FOR SATURDAY....SFC HIGH PRESSURE WILL GRADUALLY BUILD INTO THE REGION. SKIES SHOULD BECOME PARTLY CLOUDY WITH A WARMING TREND. WENT CLOSE TO MAV GUIDANCE FOR TEMPS AS IT SEEMS REASONABLE TO USE THROUGH SATURDAY. && LONG TERM (SATURDAY THROUGH WEDNESDAY)... THE FOLLOWING WAS ISSUED AT 323 PM EDT WED AUG 11 2004. NORTHWEST TO WEST FLOW ALOFT WILL KEEP WEATHER DRY THROUGH MOST OF FORECAST. TROF APPROACHING NEXT WEDNESDAY WILL REQUIRE CHANCE POPS. TEMPS WILL REMAIN BELOW AVERAGE THROUGH MONDAY. AS SURFACE HIGH MOVES EAST A SOUTHERLY FLOW WILL DEVELOP AND READINGS MAY WARM TO NEAR NORMAL BY NEXT WEDNESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. IN...NONE. KY...NONE. && $$ oh AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1157 AM EDT THU AUG 12 2004 .SHORT TERM (REST OF TODAY)... UPDATING FORECAST TO INCLUDE TORNADO WATCH IN SC FROM GREENWOOD TO CHEROKEE AND YORK COS...AND IN NC FROM GASTON CO E TO CABARRUS AND UNION. BEFFED UP POP/QPF E AS WELL. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 1000 AM EDT THU AUG 12 2004 SHORT TERM (REST OF TODAY)... SURFACE WAVE ALONG STALLED FRONT MOVING NE ACROSS N GA AT THIS TIME. LEFT ENTRANCE REGION OF UPPER LEVEL JET MAX ENHACING LIFT OT E OF WAVE. RADAR TRENDS SUGGEST PRECIPITATION TO WANE THIS AFTERNOON... BUT LATEST RUC WINDS INDICATE AN INCREASING UPSLOPE COMPONENT AS CIRCULATION OF TS BONNIE APPROACHES. WILL LEAVE POPS CATEGORICAL THROUGH AFTERNOON...AND CONTINUE FLOOD WATCH. STILL A CONCERN FOR SEVERE WEATHER WITH DIRECTIONAL WIND SHEAR ASSOCIATED WITH BONNIE... ESPECIALLY PIEDMONT IN UNSTABLE AIR ON E SIDE OF FRONT. TEMPERATURES AND DEW POINTS AROUND FORECAST VALUES. HAVE LOWERED TEMPERATURES A DEGREE TOWARD THE COOL 06Z MAV NUMBERS. CLOUD COVER GRADIENT EXIST IN E...BUT BELIEVE THIS WILL FILL IN WITH ADDITONAL MOISTURE MOVING INTO AREA. THE FOLLOWING WAS ORIGINALLY ISSUED AT 341 AM EDT THU AUG 12 2004 SHORT TERM (TODAY THROUGH FRIDAY)... A STALLED FRONTAL BOUNDARY ALONG THE EASTERN SLOPES OF THE APPALACHIANS WILL COMBINE WITH STRONG SUPPORT FROM THE RIGHT ENTRANCE REGION OF THE UPPER JET STREAK AND THE INFLUX OF DEEP TROPICAL MOISTURE TO PRODUCE WIDESPREAD HEAVY RAINFALL ACROSS THE REGION TODAY. THE HEAVIEST RAINFALL WILL LIKELY PRECEDE THE CIRCULATION OF THE REMNANTS OF BONNIE WITH A DEEP UPSLOPE FLOW OF TROPICAL MOISTURE DEVELOPING. BANDED SHOWERS AROUND BONNIE WILL ADD TO THE TOTALS... WITH RAINFALL AMOUNTS OF 2 TO 4 INCHES STILL LIKELY. THE WINDS FROM BONNIE SHOULD STEADILY DIMINISH ACROSS GA AND IN SC BY TONIGHT...BUT WINDY CONDITIONS CLOSE TO ADVISORY MAY PERSIST ACROSS THE EXTREME ERN PIEDMONT SECTIONS OVERNIGHT. THIS AREA WILL NEED TO BE WATCHED FOR A WIND ADVISORY WITH LATER ISSUANCES. LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)... A VERY BRIEF RESPITE IS EXPECTED FRIDAY AFTERNOON IN THE WAKE OF BONNIE AND AHEAD OF THE REMNANTS OF CHARLEY. LATEST GFS CONTINUES TO BRING CHARLEY FARTHER INLAND INTO THE CAROLINAS. WILL NUDGE THE FORECAST TOWARD HIGHER RAIN CHANCES AND STRONGER WINDS...ESPECIALLY NEAR CLT METRO AREA. PLAN ON ISSUING AN ESF FOR THE FOOTHILLS AND PIEDMONT TO ADDRESS FURTHER FLOODING THREAT IF CONVECTION FROM CHARLEY MAKES IT THIS FAR WEST. AVIATION... ON THE LARGE SCALE...CONDITIONS GRADUALLY DETERIORATING STARTING THIS MORNING AS WAVES OF DEEP CONVECTION ARE EXPECTED TO CONTINUE TO DEVELOP AND MOVE NORTH ACROSS THE TERMINALS. SOUTHERLY FLOW OF DEEPER MOISTURE WILL BE INTERACTING WITH STALLED FRONTAL ZONE AND ENHANCED BY FAVORABLE RIGHT ENTRANCE REGION CIRCULATIONS FROM STRONG UPPER JET. WE WILL ALSO WILL BE COMING UNDER INCREASING DIRECT INFLUENCE FROM THE REMNANTS OF BONNIE LATER THIS AFTERNOON AND EVENING. THE MAJORITY OF THE TAF PERIOD WILL FEATURE CIG/VSBYS DUE TO SHOWERS AND THUNDERSTORMS PREDOMINATELY WITHIN MVFR RANGE WITH OCCASIONAL REDUCTIONS TO IFR CONDITIONS WITHIN HEAVIER PCPN BANDS. SFC WINDS MOSTLY FROM THE SE DURING THE WITH A BACKING TO NE THIS EVENING. HYDROLOGY... FLOOD WATCH IS ALREADY IN PLACE...BUT WILL ADJUST BEGINNING TIME TO COINCIDE WITH FORECAST ISSUANCE THIS MORNING SINCE TROPICAL RAINFALL IS ALREADY INVADING FROM THE SOUTH EARLY THIS MORNING. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...FLOOD WATCH FOR ZONES GAZ010-017-018-026-028-029 THROUGH FRIDAY. NC...FLOOD WATCH FOR ZONES NCZ033>035-037-038-048>059-062>072- 082 THROUGH FRIDAY. ...TORNADO WATCH FOR ZONES NCZ069>072-082 UNTIL 6 PM EDT. SC...FLOOD WATCH FOR ZONES SCZ001>014-019 THROUGH FRIDAY. ...TORNADO WATCH FOR ZONES SCZ009-012>014-019 UNTIL 6 PM EDT. && $$ SHORT TERM (UPDATE)... sc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1000 AM EDT THU AUG 12 2004 .SHORT TERM (REST OF TODAY)... SURFACE WAVE ALONG STALLED FRONT MOVING NE ACROSS N GA AT THIS TIME. LEFT ENTRANCE REGION OF UPPER LEVEL JET MAX ENHACING LIFT OT E OF WAVE. RADAR TRENDS SUGGEST PRECIPITATION TO WANE THIS AFTERNOON... BUT LATEST RUC WINDS INDICATE AN INCREASING UPSLOPE COMPONENT AS CIRCULATION OF TS BONNIE APPROACHES. WILL LEAVE POPS CATEGORICAL THROUGH AFTERNOON...AND CONTINUE FLOOD WATCH. STILL A CONCERN FOR SEVERE WEATHER WITH DIRECTIONAL WIND SHEAR ASSOCIATED WITH BONNIE... ESPECIALLY PIEDMONT IN UNSTABLE AIR ON E SIDE OF FRONT. TEMPERATURES AND DEW POINTS AROUND FORECAST VALUES. HAVE LOWERED TEMPERATURES A DEGREE TOWARD THE COOL 06Z MAV NUMBERS. CLOUD COVER GRADIENT EXIST IN E...BUT BELIEVE THIS WILL FILL IN WITH ADDITONAL MOISTURE MOVING INTO AREA. && .PREVIOUS DISCUSSION. ****ERROR: INCOMPLETE DATA sc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SAN ANGELO TX 858 PM CDT THU AUG 12 2004 .UPDATE... NO CHANGES ANTICIPATED FOR THE CURRENT FORECAST PACKAGE. BIG EVENT FOR TONIGHT WILL BE THE DEVELOPING MCS NOW OVER SOUTHEAST NEW MEXICO. LATEST RUC MODEL HAS THIS MCS MOVING SOUTHEAST AND PLACES MCS JUST WEST OF FORECAST AREA BY TOMORROW MORNING WITH BEST RAINFALL CHANCES OVER WESTERN SECTIONS OF CWA. CURRENT PACKAGE MAPS OUT RAINFALL PATTERN PER THIS SCENARIO. PRECIPITATION IN NORTHERN TIER OF COUNTIES HAS NOT BEEN ABLE TO SUSTAIN INTENSITY AND WILL YIELD TO THE BETTER DYNAMICS CURRENTLY OVER SOUTHEAST NEW MEXICO. && .PREV DISCUSSION... NORTHWEST FLOW ALOFT TO CONTINUE THROUGH MOST OF THE FORECAST... WITH COOLER THAN NORMAL TEMPS EXPECTED THROUGH AT LEAST THE WEEKEND. AS IS TYPICAL WITH NORTHWEST FLOW...PRIMARY FORECAST CONCERN REMAINS RAIN CHANCES. KAMA/KLBB RADARS INDICATED ISOLATED THUNDERSTORMS OVER THE TX PANHANDLE AT MIDAFTERNOON. GOES VISIBLE IMAGERY INDICATED SLIGHT CYCLONIC CIRCULATION WITHIN THE CLOUD FIELD JUST NORTHWEST OF HASKELL COUNTY. SURFACE DEWPOINTS OVER THE PANHANDLE WERE RUNNING ABOUT 10 DEGREES WARMER THAN OVER WEST CENTRAL TX AT MIDAFTERNOON... QUITE UNUSUAL. GOES VISIBLE IMAGERY ALSO INDICATED THUNDERSTORMS HAD FORMED OVER THE MOUNTAINS OF NORTH CENTRAL/NORTHEAST NM. EXPECT THUNDERSTORMS OVER THE PANHANDLE AND NORTHEAST NM TO EVENTUALLY FORM AN MCS THIS EVENING. EXPECT THE MCS TO MAINTAIN ITSELF DURING THE OVERNIGHT HOURS...AIDED BY A DEVELOPING 30-40KT LOW LEVEL JET/THETA-E RIDGE EXTENDING FROM THE TRANS-PECOS INTO SOUTHEAST NM. REGARDING RAIN CHANCES...WILL PLAN HIGH CHANCE POPS OVER WESTERN CROCKETT/FAR WESTERN CONCHO VALLEY...TAPERING OFF TO VERY LOW CHANCE POPS FURTHER EAST...OVER THE HEARTLAND. POST- SHORTWAVE SUBSIDENCE AND DECAYING LOW LEVEL JET SHOULD LIMIT THUNDERSTORM COVERAGE BEYOND MIDMORNING FRIDAY...WITH ONLY ISOLATED THUNDERSTORMS EXPECTED DURING THE AFTERNOON. UPPER LEVEL FLOW DEAMPLIFIES FROM FRIDAY THROUGH THE WEEKEND... AS UPPER LEVEL HEIGHTS BUILD SLIGHTLY OVER WEST CENTRAL TX. GFS MODEL PROGS NUMEROUS SHORTWAVE DISTURBANCES TRAPPED UNDER THE UPPER RIDGE OUT WEST...EMBEDDED IN THE MONSOONAL FLOW. APPEARS WEST CENTRAL TX WILL REMAIN EAST OF THE MAIN AXIS OF MONSOONAL FLOW...WITH WEAK CONFLUENT FLOW ALOFT. WILL MAINTAIN LOW CHANCE POPS IN THE FORECAST GRIDS. UPPER LEVEL LONGWAVE TROF OVER THE EASTERN U.S. SHOWS SOME SIGNS OF LIFTING BY MID TO LATE NEXT WEEK...PLACING WEST CENTRAL TX IN WEAK ZONAL FLOW ALOFT. GIVEN PROXIMITY TO MONSOONAL MOISTURE AND CHANCE OF ISOLATED AFTERNOON STORMS...WILL MAINTAIN 10 PERCENT POPS THROUGH MOST OF THE OUTER PERIODS. WITH ONSET OF MORE ZONAL FLOW...AND ASSUMING CLOUDS ARE NOT TOO THICK...A RETURN TO NEAR NORMAL TEMPS EXPECTED BY THE MIDDLE OF NEXT WEEK. && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/15 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LUBBOCK TX 400 PM CDT THU AUG 12 2004 .SHORT TERM... ACTIVE PATTERN IN STORE FOR MUCH OF THE TX PANHANDLE...SOUTH PLAINS AND LOW ROLLING PLAINS BEGINNING THIS EVENING AND LASTING INTO FRIDAY MORNING. LATEST WATER VAPOR LOOP WITH RUC HEIGHTS SHOWING UNUSUALLY STRONG NW FLOW ALOFT OVER MUCH OF THE CENTRAL AND SOUTH PLAINS. GOOD LOW LEVEL 850MB MOISTURE...NW FLOW ALOFT ATMOSPHERIC DESTABILIZATION AND SHEAR WILL WORK IN TANDEM TO DEVELOP COMPLEX OF SHOWERS AND THUNDERSTORMS FROM EASTERN NM/ SE CO THIS EVENING. SCATTERED ACTIVITY NOW UNDERWAY FROM THE EASTERN PANHANDLE THROUGH THE CAPROCK. MCS EVOLUTION WITH SOUTHWARD PROPAGATION LIKELY TONIGHT. KEPT LIKELY POPS ALONG AND WEST OF 1-27 AND UPPED TO 70 POPS OVER THE FAR WEST CWA. EXPECTING MAIN THREATS TO BE DAMAGING WINDS AND LOCALIZED HEAVY RAINFALL. MCS SHOULD DEPART THE LUB CWA BY FRIDAY 15Z WITH A FEW LINGERING SHOWERS POSSIBLE OVER THE SW TIER OF COUNTIES. LEFTOVER DEBRIS CLOUDS AND MOISTURE COULD ONCE AGAIN HOLD MAX TEMPS IN THE LOWER TO MIDDLE 80S AT BEST. UPDATED HWO SENT OUT THIS MORNING TO COVER STORM COMPONENTS THROUGH FRIDAY. THANKS TO MAF AND SJT FOR COORDINATION TODAY. WIDELSKI .LONG TERM... NW FLOW PATTERN STAYS IN PLACE THROUGH THE WEEKEND. IN ADDITION WE SHOULD HAVE THE 850MB FRONTAL ZONE MEANDERING ACROSS THE REGION FRI EVE BEFORE LIFTING BACK NORTH ON SAT. FEEL THAT FRI EVEN WE MAY SEE SHOWERS AND TSTM ACTIVITY CONCENTRATED ALONG THE FRONT WHERE AS SAT NIGHT WE WILL HAVE THE POTENTIAL FOR STORMS COMING IN FROM THE NM MTNS AS THE SOUTHERLY LLJ BECOMES REESTABLISHED. LOW-LEVEL MOISTURE LEVELS HAVE SLOWLY DROPPED BEHIND THE LAST FRONT...WHICH MAY SOMEWHAT TEMPER TSTM COVERAGE FRI NITE. BEHIND THE RETREATING WARM FRONT ON SAT THOUGH WE SHOULD SEE DEWPOINTS BEGIN TO INCREASE AGAIN. THE CHANCE OF MAINLY EVENING AND OVERNIGHT STORMS LOOKS LIKE IT WILL CONTINUE THRU MONDAY NIGHT AS THE NEXT SHTWV TROF DIVES INTO THE MIDWEST. TEMP PROFILE AND THICKNESS VALUES SHOW LITTLE CHANGE THROUGH THE WEEKEND...MEANING TEMPS WILL BE HIGHLY DEPENDENT ON AMOUNT OF RAINFALL AND CLOUD COVER. OPTED NOT TO MAKE MANY CHANGES ATTM...KEEPING PARTLY TO MOSTLY CLOUDY SKIES AND A SLOW WARMING TREND. UPPER-AIR PATTERN IS ADVERTISED TO DE-AMPLIFY BY MID WEEK WITH THE WRN CONUS RIDGE SLOWLY FLATTENING AND SPREADING EASTWARD A BIT AS SEVERAL SHTWVS MOVE THROUGH THE INTER-MTN REGION. THIS PATTERN CHANGE MAY NOT HAPPEN AS QUICKLY AS THE GFS DEPICTS GIVEN THE STRENGTH OF THE RIDGE/TROF. BUT THIS SHOULD ACT TO REDUCE CONVECTION OVER NM AND THUS THE THREAT FOR STORMS MOVING INTO THE SPLNS. IT SHOULD ALSO ACT TO BOOST HIGH TEMPS INTO THE 90S AGAIN. A STRONG UPR-TROF MOVING ACROSS CANADA WILL PUSH ANOTHER SEASONALLY STRONG COLD FRONT INTO THE CENTRAL PLAINS ON WED WITH IT APPROACHING THE TX PANHANDLE AND SOUTH PLAINS BY THU. MAY SEE A GREATER CHANCE OF TSTMS AND SLIGHTLY COOLER TEMPS BY NEXT WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 59 80 58 82 / 70 20 30 20 TULIA 60 80 59 84 / 60 20 30 20 PLAINVIEW 61 80 61 84 / 60 20 30 20 LEVELLAND 60 80 61 82 / 70 30 30 20 LUBBOCK 62 80 62 83 / 60 30 30 20 BROWNFIELD 61 80 61 82 / 70 30 30 20 CHILDRESS 64 83 63 86 / 40 20 20 20 SPUR 64 82 62 84 / 50 30 20 20 ASPERMONT 64 84 63 85 / 40 30 20 20 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 17/33 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 410 AM CDT FRI AUG 13 2004 .UPDATE... 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... 0300 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 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...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 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...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