WEST CENTRAL AND SOUTHWEST FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL 827 PM EDT SAT AUG 7 2004 .DISCUSSION...STATIONARY FRONT LAID OUT WEST TO EAST ACROSS CENTRAL FLORIDA THIS EVENING WITH NUMEROUS SHOWERS AND A FEW THUNDERSTORMS IN THE VICINITY OF BOUNDARY. VERY SLOW MOVEMENT OF ACTIVITY HAS ALLOWED VERY HEAVY RAINFALL OVER 3 INCHES AN HOUR TO OCCUR IN SOME SPOTS... INCLUDING HERE AT THE NWS OFFICE WHERE 4.40 INCHES FELL IN JUST OVER AN HOUR. TPA HAS ALSO ESTABLISHED A NEW DAILY RAINFALL RECORD FOR THE DATE WITH 4.14 INCHES SO FAR TODAY BREAKING THE PREVIOUS RECORD SET IN 2002 OF 2.56 INCHES. NUMEROUS LOCATIONS REPORTING STANDING WATER ACROSS THE TAMPA BAY AREA THIS EVENING. WILL NEED TO CONTINUE MONITORING RADAR TRENDS OVERNIGHT AND LIKELY THE NEXT COUPLE OF DAYS WITH MORE HEAVY RAIN POSSIBLE AS FRONT LINGERS ACROSS REGION. MAY NEED A FLASH FLOOD WATCH...BUT WILL LET OVERNIGHT SHIFT TAKE A LOOK AT LATEST MODELS BEFORE DECIDING IF THIS IS NECESSARY. SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE OVERNIGHT... MAINLY IN VICINITY OF BOUNDARY. HOWEVER...ACTIVITY SHOULD BEGIN TO FOCUS MORE OVER COASTAL WATERS WITH LOSE OF DIURNAL HEATING. WILL UPDATE ZONES LATER THIS EVENING TO ADJUST SOUTHERN ZONE POPS DOWN SOME...OTHERWISE NO MAJOR CHANGES PLANNED. && .MARINE...WINDS OVER NORTHERN COASTAL WATERS HAVE CONTINUED TO INCREASE TO AROUND 20 KNOTS WITH HIGHER GUSTS. LATEST RUC CONTINUES THESE WINDS OVERNIGHT AND WILL NEED TO UPDATE SOON TO ACCOUNT FOR THIS AND GO WITH SMALL CRAFT ADVISORY. WINDS SHOULD SUBSIDE LATE TONIGHT WITH REMAINDER OF FORECAST OKAY AT THIS TIME. && .TBW WATCHES/WARNINGS/ADVISORIES...SMALL CRAFT ADVISORY TONIGHT FOR TARPON SPRINGS TO SUWANNEE RIVER OUT TO 60 NM. && $$ PRC fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 950 AM EDT SAT AUG 7 2004 .SHORT TERM...CONVERGENCE SHOWERS CONTINUE ACROSS FLAGLER COUNTY... ALTHO MORE PERSISTENT ACTIVITY HAS CONTINUED JUST S OF THE CWA (COUNTY WARNING AREA). STILL...WITH PRESENT COVERAGE AND RUC INDICATING THAT THIS PRECIP WILL CONTINUE...WILL NEED TO BUMP POPS A BIT FOR THE EXTREME SE ZONES. CLOUDS ACROSS THIS AREA WILL NEED TO BE BUMPED UP AS WELL...EITHER TO VARIABLE CLOUDINESS OR MOSTLY CLOUDY. TEMPS APPEAR TO BE ON TRACK. && .MARINE...FCST IS ON TRACK WITH LITTLE CHANGE EXPECTED. && .JAX WATCHES/WARNINGS/ADVISORIES... FL...SMALL CRAFT ADVISORY AMZ452/454/472/474. GA...SMALL CRAFT ADVISORY AMZ450/470. && $$ CARROLL/DEESE/KERNS fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 208 PM MDT SAT AUG 7 2004 .DISCUSSION...CONVECTION IS DEVELOPING OVER THE FRONT RANGE OF THE ROCKIES THIS AFTERNOON. RUC PUSHES CONVECTION OVER THE PLAINS AFTER 21Z...AND ALONG THE KS/CO BORDER BY 00Z. THIS IS REASONABLE GIVEN SURFACE DEWPOINTS IN THE MID 60S IN NORTHWEST KANSAS. SOME UNOFFICIAL MESONET SITES ARE EVEN SHOWING DEWPOINTS IN THE LOWER 70S. WATER VAPOR IMAGERY SHOWS A DECENT SHORT WAVE MOVING OVER COLORADO. SURFACE TROUGH CURRENTLY EXTENDS FROM CENTRAL NEBRASKA TO SOUTHEAST COLORADO. THIS SHOULD PROVIDE ENOUGH SURFACE CONVERGENCE TO PRODUCE SCATTERED THUNDERSTORMS OVER THE WESTERN HALF OF FORECAST AREA THIS EVENING. WILL MONITOR CONVECTIVE DEVELOPMENT THROUGH THE AFTERNOON AND ADJUST THE FORECAST ACCORDINGLY. COLD FRONT REMAINS ON TRACK...AND WILL PUSH THROUGH THE AREA BETWEEN 15Z-18Z SUNDAY. THE AIR MASS WILL CONTINUE TO BE MOIST SOUTH OF THE FRONT...SO EXPECT CONVECTION TO DEVELOP ALONG FEATURE DURING THE EARLY AFTERNOON. THE BEST CHANCE WILL BE SOUTH AND EAST IN THE FORECAST AREA. TEMPERATURES SHOULD WARM AHEAD OF THE FRONT TO LEVELS SLIGHTLY HIGHER THAN NUMERICAL GUIDANCE. THE AIR MASS WILL DRY AND COOL BEHIND FRONT FOR A MILD DAY MONDAY. NORTHWEST FLOW ALOFT WILL REMAIN OVER THE PLAIN STATES THROUGH MID WEEK. OCCASIONAL SHORTWAVES AND POSITION OF 300 MB JET SUPPORT BRINGING A CHANCE OF THUNDERSTORMS TUESDAY. COOL AIR MASS MAY INHIBIT SURFACE INSTABILITY TUESDAY...BUT UPSLOPE SURFACE WINDS AND UPPER DYNAMICS SHOULD BE ENOUGH TO OVERCOME THE LIMITATION. TEMPERATURES TUESDAY WILL BE TRICKY. THERE IS A POSSIBILITY OF BEING UNDER A LOW OVERCAST DURING THE DAY...SO TEMPERATURES IN THE UPPER 60S ARE POSSIBLE. ON THE OTHER HAND...CLEARING SKIES WOULD PRODUCE TEMPERATURES IN THE LOWER 80S. WILL PAINT A LARGE THERMAL CONTRAST FROM WEST...WHICH WILL BE WARMER AND DRIER...TO THE EAST. NORTHWEST FLOW WILL CONTINUE THE REST OF THE FORECAST AS 500 MB RIDGE EXTENDS OVER THE WESTERN UNITED STATES AND HUDSON BAY LOW REMAINS THERE. THIS WILL PROVIDE THE AREA WITH BELOW NORMAL TEMPERATURES. ALTHOUGH WILL KEEP THE FORECAST DRY DUE LACK OF MAJOR SURFACE OR MID LEVEL FEATURES...MINOR SHORTWAVES COULD PRODUCE CONVECTION DURING ANY OF THE EXTENDED DAYS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ MENTZER ks AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE WICHITA KS 1044 AM CDT SAT AUG 7 2004 MAIN CONCERN WITH THIS AFTERNOON IS TEMPERATURES AND CLOUD COVER. LATEST RADAR IMAGERY SHOWING SHOWERS START TO DISSIPATE ACROSS SOUTH CENTRAL KANSAS. THIS TREND SHOULD CONTINUE AS THE 800-700MB LEVEL FLOW CONTINUES TO DECREASE WHICH WILL WEAKEN THE UPGLIDE. I AM BIT CONCERNED THE MVFR CLOUDS MAY CREEP INTO PARTS OF RUSSELL AND GREAT BEND WHICH MAY RESTRICT THEIR TEMPERATURES A LITTLE MORE, BEFORE THE SUN HELPS ERODE IT. ETA/GFS/RUC ALL SHOW A COLD POCKET HANGIN ON IN CENTRAL KANSAS THROUGH THE EARLY AFTERNOON WHICH WILL HELP PRODUCE THE CU FIELD EVEN IF THE MVFR CLOUDS ERODE. SOUTH CENTRAL KANSAS MAY SEE CEILINGS OF 100-150KFT HOLD ON THROUGH MOST OF THE DAY AS A MID LEVEL COLD POCKET STAYS IN PLACE. WE HAVE LOWERED TEMPERATURES IN THIS REGION AS WELL. COX -------------------------------------------------------------------- 410 AM CDT SAT AUG 7 2004 .DISCUSSION.... TODAY: LOWEST 12-15KFT OF AIRMASS VERY DRY OVER CWA DUE PRIMARILY TO CLOSER PROXIMITY TO 850-MB HIGH POSITIONED OVER CNTRL MS VALLEY. THEREFORE, XPCT LITTLE MORE THAN FEW SPRINKLES OVER HARPER & KINGMAN COUNTIES THIS MRNG WHERE 15-20% POPS ASSIGNED. EXTENSIVE CLOUD COVER DICTATES LOWERING MAXES ALL AREAS TO ~85F W/ MOST AREAS ON COOLER SIDE OF FENCE. TNGT: BEST SFC-850MB CONVERGENCE TARGETING SD & NEBRASKA WHERE CLOSER TO CDFNT SURGING SE AS WELL-DEFINED 500-300MB TROF SCOOTS E OVER U.S./CANADIAN BDR. PER THIS REASON REMOVED ~20% POPS FM CNTRL KS FOR LATE TNGT. SUN: AS UPR TROF CONTS MOVG E OVER XTRM ND CDFNT TO CONT MOVG SE TWD CNTRL KS TO INCR CHCS FOR TSRA FOR CNTRL KS WHERE HIGHEST POPS (~40%) ASSIGNED TO RUSSELL & LINCOLN COUNTIES. INCRG CLOUD COVER IN ADVANCE OF APCH'G CDFNT DICTATE LOWERING MAXES TO ~90F W/ SC KS ON WARMER SIDE OF FENCE. SUN NGT: W/ UPR LOW DVLP'G OVER NRN MN, XPCT CDFNT'S SE PROGRESS TO DECELERATE TO ALLOW EXTRA SFC-850MB MSTR TO POOL IN VCNTY OF BNDRY AS IT SAGS S/SE ACRS CNTRL & SC KS. INCR'D POPS ACRS CNTRL & SC KS TO 50-60% W/ POPS IN SE KS INCR'D TO 40-50% W/ EMPHASIS 1A-7A TIMEFRAME DUE TO LATER ARVL OF CDFNT. MON: W/ CDFNT SAGGING S/SE ACRS KS/OK BDR, GREATEST POP POTL TO TARGET AREAS ALG OK BDR WHERE POPS INCR'D TO ~40%. W/ INVERTED SFC RIDGE BLDG SE INTO VCNTY NEBRASKA PANHANDLE COOLER AIR TO MIGRATE S TWD CNTRL KS WHERE INHERITED MAXES OF UPR 70S APR KOSHER. MON NGT: UNSEASONABLY COOL AIR CONT'S TO INFILTRATE CWA W/ CNTRL KS AGAIN DIPPING INTO THE UPPER 50S. && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 84 66 91 69 / 10 0 10 60 HUTCHINSON 85 67 90 69 / 10 0 20 50 NEWTON 85 67 90 68 / 5 0 20 60 ELDORADO 84 66 91 68 / 5 0 10 60 WINFIELD-KWLD 84 65 91 69 / 10 0 10 60 RUSSELL 86 67 88 66 / 5 0 40 60 GREAT BEND 86 67 89 67 / 10 0 30 60 SALINA 86 68 89 67 / 0 0 30 60 MCPHERSON 85 67 90 68 / 5 0 20 60 COFFEYVILLE 83 63 89 66 / 0 0 5 50 CHANUTE 82 63 89 66 / 0 0 10 50 IOLA 82 63 89 66 / 0 0 10 50 && .ICT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 4/ES ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 927 AM EDT SAT AUG 7 2004 .UPDATE... LATEST RADAR SHOWS ISOLATED SHOWERS ACROSS THE MOUNTAINS AND FOOTHILLS. EXPECT THIS COVERAGE TO EXPAND AS DAYTIME HEATING CONTINUES TO DESTABILIZE THE ATMOSPHERE. 12Z SOUNDING SHOWS MODEST CAPES OF 300 J/KG AT GYX THIS AFTERNOON...WITH A CAP AT AROUND 14K FT. 09Z RUC SHOWS CAPES BUILDING TO 1000 J/KG ACROSS CENTRAL MAINE LATE AFTERNOON. WHILE THIS MAY BE OVERDONE...FEEL THERE WILL BE SUFFICIENT INSTABILITY FOR SHOWERS TO DEVELOP THIS AFTERNOON. NORTH OF PORTLAND...GIVEN LOW FREEZING LEVELS (8000 FT ON 12Z GYX SOUNDING)...EXPECT A FAIR AMOUNT OF SHOWERS TO PRODUCE SMALL HAIL. GIVEN THE CAP IN PLACE...DO NOT EXPECT UPDRAFTS TO SUPPORT MUCH LARGER THAN PEA-SIZED HAIL. WITH LOW FREEZING LEVELS SUPPORTING GOOD GRAUPEL FORMATION...FEEL ISOLATED THUNDERSTORMS ARE ALSO POSSIBLE. WILL UPDATE ZONES TO REFLECT THIS...BUT WILL KEEP FORECAST AS IS IN SOUTHERN NEW HAMPSHIRE AND EXTREME SOUTHERN MAINE WHERE THERE ARE HIGHER FREEZING LEVELS AND LOWER CAPES. && .SHORT TERM (TODAY AND TONIGHT)...88D IMAGES SHOWING SHRA ROTATING ARND MID LVL CIRCULATION OVER THE NE THIS MORNING. WILL KEEP CHC POPS IN THE FCST FOR TDA AND TNGT. THE HIGHEST CHC FOR PCPN WILL BE IN THE MTNS. ETA/GFS/NGM MOS TEMPS IN RELATIVELY GOOD AGREEMENT AND ACCEPTED. CAPES CLIMB A TAD THIS AFTN. THERE MAY BE A COUPLE TSRAS...HWVR CHC IS LOW AND NEIGHBORS ARE NOT INCLUDING THIS PSBLTY. WILL OMIT FOR NOW. PATCHY FOG TO FORM TNGT. && .LONG TERM (SUNDAY THROUGH FRIDAY)... UPR VORTEX OVER NEW ENGLAND FINALLY BEGINS MOVING E ON SUNDAY. BY MONDAY UPPER VORTEX HAS LIFTED OUT AND IS REPLACED BY A SHORT WAVE RIDGE BRINGING SUNNY SKIES MONDAY AND WARMER TEMPERATURES. NEXT SYSTEM APPROACHES FROM THE W ON TUESDAY SO THE THREAT OF SHOWERS DEVELOPING EXISTS. BY MID TO LATE WEEK WE WILL BE WATCHING THE EVOLUTION OF YET ANOTHER LONG WAVE TROF DEVELOPING OVER THE GREAT LAKES AND LOWER OHIO VALLEY. THIS COULD MEAN MORE UNSETTLED WEATHER DEVELOPING LATER IN THE WEEK. TIMING WILL BE DIFFICULT AND WILL STICK WITH PREVIOUS FORECAST FORCONTINUITY PURPOSES. && .AVIATION...MID LVL DECK OVERHEAD ATTM. CLOUDS TO LWR THIS AFTN W/ SCT-ISOLD SHRA. PATCHY FOG LATE TNGT IN LEB AND POSSIBLY CON. && .MARINE...WINDS/SEAS DOWN. COULD BE LOCALIZED ONSHORE WINDS THIS AFTN. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ UPDATE: APFFEL me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 930 PM EDT SAT AUG 7 2004 .DISCUSSION... .SHORT TERM... 00Z RAOBS/WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT MEAN RDG OVER THE ROCKIES UPSTREAM OF DEEP AND PERSISTENT UPR LO OVER NRN NEW ENGLAND. SFC HI PRES RDG EXTENDING FM ONTARIO INTO THE OH VALLEY AND ASSOCIATED DRY AIRMASS DEPICTED ON THE 00Z APX SDNG (00Z KINX 5) BRINGING ANOTHER TRANQUIL NGT TO MOST OF CWA. SFC DWPTS ACRS FA IN THE 50S. HOWEVER...WEAK SHRTWV/ASSOCIATED ISENTROPIC LIFT ON 300-310K SFCS MOVING THRU UPR RDG AND INTO NW GRT LKS CAUSING CLDS OVER THE WRN HALF OF FA AND SOME -SHRA OVER THE FAR W FARTHEST AWAY FM THE CORE OF DRY AIR TO THE E HELD IN PLACE BY NW FLOW ALF ARND SLOWER MOVING NEW ENGLAND CUTOFF LO. CLD/-SHRA TENDING TO DSPT/MOVE SE AS SHRTWV GRINDS INTO THE DRY AIR AND ISENTROPIC LIFT MAX TENDS TO SHIFT MORE SE THRU WI THEN PUSH E INTO THE FA. SHRA ASSOCIATED WITH NW LKS SHRTWV EXTEND BACK INTO ERN MN/NW WI. THEN A BRK IN PCPN...BUT MORE SHRA/TSRA MOVING THRU THE DAKOTAS IN ADVANCE OF MORE POTENT SHRTWV IN MONTANA THIS EVNG THAT IS CRASHING THRU ROCKIES RDG AND INTERACTING WITH HIER PWAT/STEEPER LAPSE RATES IN THE NRN PLAINS. MAIN FCST CONCERNS TNGT ARE SHRA COVG/TMINS. LATEST RUC/GFS/ETA INDICATE SHRTWV IN THE NW LKS WL MAKE ONLY SLOW PROGRESS E TNGT AS SYS RUNS INTO PERSISTENT NW FLOW ALF ARND SLUGGISH UPR LO TO THE E. BETTER H85 WAD/ISENTROPIC LIFT ON 300-310K SFCS/H85-5 QVECTOR CNVGC TENDS TO REMAIN TO THE SW OF FA...WITH ASSOCIATED HIER MID LVL MSTR MAKING LTL PROGRESS E THRU 12Z SUN. PER MODEL QPF FIELDS...EXPECT SCT -SHRA OVER THE FAR W TO PRETTY MUCH REMAIN IN PLACE IN AN AREA W OF ONTONAGON-IRON RIVER. FARTHER E... DEBRIS MID/HI CLD WL TEND TO THIN AS CLD MASS PUSHES INTO STATIC NW FLOW. LOOK FOR MIN TEMPS TO DROP OFF TO THE E TOWARD THE HI CENTER/ AXIS OF DRIER AIR. TMINS OVER LUCE COUNTY WL DROP TOWARD THE CURRENT DWPT ARND 50. GOING FCST NEEDS ONLY MINOR ADJUSTMENTS. KC .LONG TERM... SUN...STRONG VORT/CLOSED LOW FM NRN ROCKIES MOVES INTO WRN MN TOWARD EVENING. MOISTURE ADVECTION INCREASES INTO WRN UPR MI WITH H8 DEWPOINT RISING TO NEAR 11C AND SFC DEWPOINTS INTO THE LOWER 60S. MAX TEMPS INTO THE MID 70S WOULD GIVE CAPE VALUES TO NEAR 1K J/KG. HOWEVER...IF MID CLOUDS LINGER...REDUCED INSOLATION WOULD PROVIDE ONLY MINIMAL INSTABILITY PER GFS VALUES. HOWEVER...LOW LVL THETA-E ADVECTION AND PROXIMITY OF H8 WARM FRONT WILL AT LEAST WARRANT CHANCE FOR SHRA/TSRA FROM WEST INTO CNTRL UPR MI BY AFTERNOON. SUN NIGHT INTO MON...BETTER CHC FOR SHRA/TSRA AS ADVANCING SFC CDFNT PROVIDES FOCUS WITH ADDED SUPPORT FROM DEEP LYR QVECTOR CONV AND DIFFLUENT FLOW AHEAD OF THE MID LVL LOW. ETA STILL A BIT QUICKER THAN GFS/UKMET ALTHOUGH COMPROMISE WOULD STILL SUGGEST DECENT SHRA/TSRA COVERAGE WITH LIKELY POPS WEST IN THE EVENING AND OVERNIGHT FOR THE ERN ZONES. SPC HAS SLGT RISK IN DAY2 OUTLOOK FOR WRN 2/3RDS OF CWA...ALTHOUGH WIND FIELDS STILL MARGINAL WITH 0-6KM SHEAR BLO 30 KT AND CAPES GENERALLY BLO 1K J/KG. NOT EXCITED ABOUT SVR CHCS ALTHOUGH DID MENTION POSSIBLE SMALL HAIL AND BRIEF HEAVY RAIN IN TSRA AS PWATS INCREASE TO 1.5-1.75 INCHES ALONG THE FRONT. DRY SLOT MOVING INTO THE AREA BEHIND FRONT MAY PROVIDE A BREAK FROM PCPN...ALTHOUGH MID LVL TROUGH AXIS MOVING OVERHEAD AND ASSOCIATED QG FORCING SHOULD KEEP THREAT OF SHRA/TSRA CHANCES GOING ON MON. MON NIGHT INTO TUE...UPR TROUGH LINGERING OVERHEAD AND APPROACH OF SECONDARY SFC TROUGH LATE MON NIGHT INTO TUE WILL PROVIDE MORE OPPORTUNITY FOR SHRA WITH THE BEST CHC ON TUE WITH PASSAGE OF SFC TROUGH. EXTENDED...WED-SAT)...FOLLOWING THE OPERATIONAL 00Z AND 12Z GFS AND GFS AND CANADIAN ENSEMBLES WILL KEEP IN CHC OF SHRA FOR WED AS ANOTHER SHRTWV IS PROGGED TO MOVE DOWN IN NW FLOW ON BACKSIDE OF 5H TROUGH. BESIDES SOME LINGERING MORNING SHRA FAR EAST ON THU...WENT WITH DRY FCST THU INTO SAT WITH WARMING TREND TOWARD THE WEEKEND AS OPERATIONAL MODEL CONSENSUS AND ENSEMBLES SHOW UPR TROUGH AXIS FINALLY MOVING EAST AS WEAK RDG BUILDS IN FM THE WEST. VOSS && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 448 PM EDT SAT AUG 7 2004 .DISCUSSION... MAIN FCST CONCERNS ARE -SHRA POTENTIAL W TONIGHT AND SHRA/TSRA CHANCES/COVERAGE SUN INTO MON. WV IMAGERY AND RUC ANALYSIS INDICATED A MID LVL LOW OVER THE NRN APPALACHANS...A FLAT RDG OVER CNTRL NOAM AND ANOTHER LOW/SHRTWV OVER THE NRN U.S. ROCKIES. A SHRTWV FROM WRN ONTARIO INTO NW WI ALONG WITH LOW LVL THETA-E ADVECTION AND ISENTROPIC LIFT AHEAD OF CNTRL DAKOTAS SFC LOW SUPPORTED CLUSTER OF TSRA OVER ERN MN AND NW WI. RADAR LOOP SHOWS PCPN MAKING LITTLE EASTWARD PROGRESS INTO THE DRY AIRMASS IN PLACE OVER UPR GREAT LAKES. VIS SATELLITE LOOP INDICATED MID/HIGH CLOUDS HAVE SPREAD INTO MUCH OF THE U.P...THICKEST IN THE WEST. TONIGHT...WITH 300-310K ISENTROPIC LIFT PERSISTING AND SPREADING INTO WESTERN UPR MI THIS EVENING AND MODEL FCST LOWERING OF CONDENSATION PRES DEFICITS...HAVE KEPT IN CHC OF SHOWERS FOR THE FAR WESTERN COUNTIES. NO THUNDER IS EXPECTED AS SIGNIFICANT MUCAPE REMAINS W OF THE AREA...PER ETA ADN GFS. OTHERWISE...INCREASING MID/HIGH CLOUDS WILL LIMIT RADIATIONAL COOLING WEST AND CENTRAL KEEPING MIN TEMPS GENERALLY IN THE MID 50S TO UPR 50S. DRIER DWPNTS AND LIGHTER WINDS EAST WILL ALLOW TEMPS TO DIP AROUND 50 THERE. SUN...STRONG VORT/CLOSED LOW FM NRN ROCKIES MOVES INTO WRN MN TOWARD EVENING. MOISTURE ADVECTION INCREASES INTO WRN UPR MI WITH H8 DEWPOINT RISING TO NEAR 11C AND SFC DEWPOINTS INTO THE LOWER 60S. MAX TEMPS INTO THE MID 70S WOULD GIVE CAPE VALUES TO NEAR 1K J/KG. HOWEVER...IF MID CLOUDS LINGER...REDUCED INSOLATION WOULD PROVIDE ONLY MINIMAL INSTABILITY PER GFS VALUES. HOWEVER...LOW LVL THETA-E ADVECTION AND PROXIMITY OF H8 WARM FRONT WILL AT LEAST WARRANT CHANCE FOR SHRA/TSRA FROM WEST INTO CNTRL UPR MI BY AFTERNOON. SUN NIGHT INTO MON...BETTER CHC FOR SHRA/TSRA AS ADVANCING SFC CDFNT PROVIDES FOCUS WITH ADDED SUPPORT FROM DEEP LYR QVECTOR CONV AND DIFFLUENT FLOW AHEAD OF THE MID LVL LOW. ETA STILL A BIT QUICKER THAN GFS/UKMET ALTHOUGH COMPROMISE WOULD STILL SUGGEST DECENT SHRA/TSRA COVERAGE WITH LIKELY POPS WEST IN THE EVENING AND OVERNIGHT FOR THE ERN ZONES. SPC HAS SLGT RISK IN DAY2 OUTLOOK FOR WRN 2/3RDS OF CWA...ALTHOUGH WIND FIELDS STILL MARGINAL WITH 0-6KM SHEAR BLO 30 KT AND CAPES GENERALLY BLO 1K J/KG. NOT EXCITED ABOUT SVR CHCS ALTHOUGH DID MENTION POSSIBLE SMALL HAIL AND BRIEF HEAVY RAIN IN TSRA AS PWATS INCREASE TO 1.5-1.75 INCHES ALONG THE FRONT. DRY SLOT MOVING INTO THE AREA BEHIND FRONT MAY PROVIDE A BREAK FROM PCPN...ALTHOUGH MID LVL TROUGH AXIS MOVING OVERHEAD AND ASSOCIATED QG FORCING SHOULD KEEP THREAT OF SHRA/TSRA CHANCES GOING ON MON. MON NIGHT INTO TUE...UPR TROUGH LINGERING OVERHEAD AND APPROACH OF SECONDARY SFC TROUGH LATE MON NIGHT INTO TUE WILL PROVIDE MORE OPPORTUNITY FOR SHRA WITH THE BEST CHC ON TUE WITH PASSAGE OF SFC TROUGH. EXTENDED...WED-SAT)...FOLLOWING THE OPERATIONAL 00Z AND 12Z GFS AND GFS AND CANADIAN ENSEMBLES WILL KEEP IN CHC OF SHRA FOR WED AS ANOTHER SHRTWV IS PROGGED TO MOVE DOWN IN NW FLOW ON BACKSIDE OF 5H TROUGH. BESIDES SOME LINGERING MORNING SHRA FAR EAST ON THU...WENT WITH DRY FCST THU INTO SAT WITH WARMING TREND TOWARD THE WEEKEND AS OPERATIONAL MODEL CONSENSUS AND ENSEMBLES SHOW UPR TROUGH AXIS FINALLY MOVING EAST AS WEAK RDG BUILDS IN FM THE WEST. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1058 AM EDT SAT AUG 7 2004 .DISCUSSION... THE MAIN CONCERN WITH THIS UPDATE IS THE SHOWERS POTENTIAL OVER WESTERN U.P. THIS AFTERNOON AND THE HIGH TEMPERATURES. WATER VAPOR IMAGERY AND RUC/ETA SHOWING A CLOSED LOW OVER SOUTHERN QUEBEC AND A BROAD RIDGE OVER THE WESTERN TWO THIRD OF CONUS. A SHORTWAVE IS OVER MINNESOTA AND A WEAK LOW IS OVER WESTERN MONTANA. SURFACE ANALYSIS DEPICTS A RIDGE BLANKETING THE MIDDLE MISSISSIPPI RIVER VALLEY...OHIO RIVER VALLEY AND THE UPPER GREAT LAKES REGION. A SURFACE LOW IS OVER SOUTHEAST SASKATCHEWAN WITH A COLD FRONT EXTENDING SOUTH INTO EASTERN MONTANA. VISIBLE IMAGERY SHOWING A BROAD CLOUD SHIELD SPREADING OVER THE WESTERN HALF OF THE U.P. FROM THUNDERSTORMS DEVELOPING OVER MINNESOTA IN ASSOCIATION WITH THE SHORTWAVE. THE CLOSED LOW WILL MOVE INTO NORTHEAST CONUS. THE SHORTWAVE WILL MOVE INTO NORTHERN WISCONSIN...AND WESTERN ONTARIO. THE SURFACE RIDGE WILL REMAIN OVER THE FORECAST AREA. THE COLD FRONT WILL SLIDE INTO THE CENTRAL DAKOTAS. LOW LEVEL MOISTURE WILL BE DRAWN INTO THE WEST END OF THE FORECAST AREA BEHIND THE RIDGE AND IN ASSOCIATION WITH THE SHORTWAVE. Q-VECTOR CONVERGENCE WILL BE STRONGEST OVER WISCONSIN THIS AFTERNOON. THE ENTRANCE REGION OF A 70 KNOT UPPER LEVEL JET WILL OVER LOWER MICHIGAN. RUC SOUNDING FORECAST PROGGED TO BE SATURATED FROM 850MB THROUGH 500MB OVER THE WEST END OF THE FORECAST AREA THIS AFTERNOON. IT APPEARS TO BE DRY BELOW 850MB. SHOWERS LOOK POSSIBLE OVER THE WEST END. HOWEVER...THIS SHOULD EVAPORATE BEFORE REACHING THE GROUND. THE QUESTION WILL BE HOW MUCH OF THE LOW LEVEL WILL SATURATE OUT. A FEW SPRINKLES LOOK POSSIBLE OVER THE WEST END. A CLOUD SHIELD FROM THE BLOW OFF OF THE STORMS OVER WISCONSIN WILL LIMIT HEATING OVER THE WEST. WILL STICK CLOSE TO GUIDANCE THERE. WITH LESS CLOUD COVER OVER THE CENTRAL AND EAST...THERE SHOULD BE MORE SURFACE HEATING. WITH THE AIR MASS OVER THE LAKE TEMPERATURES IN THE UPPER 50S. SOME LAKE BREEZES WILL SET UP THIS AFTERNOON AS SURFACE HEATING OCCURS. WILL LEAVE TONIGHT FORECAST ALONE UNTIL HAVE A CHANCE TO FURTHER EVALUATE THE NEW MODELS. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE BINGHAMTON NY 950 PM EDT SAT AUG 07 2004 .SHORT TERM (TNGT - MONDAY)... UPDATING TO ADJUST MAINLY SKY GRIDS...POPS AND WX PLUS FRESHEN ZFP WORDS FOR OVERNIGHT PERIOD. DEEP CYCLONE OVER NEW ENGLAND WITH COLD POLAR FLOW OVER WARM LAKE KEEPS INSTABILITY AND LAKE INDUCED CLOUDS AND SHOWERS GOING IN A PLUME TARGETING THE FINGER LAKES. EXPECT LTL CHANGE TO THIS TNGT...BUT SRN EXTENT WILL BE LIMITED. SHRA OVER WRN CATSKILLS WL ALSO DRY UP AS VORT ENERGY EXITS SOUTH IN A FEW HOURS PER RUC. LOTS OF HOLES DVLPG IN CLOUD COVER...SO THINNED OUT SKY GRIDS ABOUT 20-30% BY SUN MORNING TO GIVE MUCH OF NEPA AND SCNTRL NY A P/C FCST. TEMPS DROPPING OFF A BIT FASTER THAN ERLYR TREND...BUT PER DEWS...FINAL MINS STILL LOOK GOOD. ONLY TWEEKED BY A DEGREE OR SO...BUT SAME CATEGORY. BREWSTER PREVIOUS THOUGHTS...DESPITE THE LEFTOVER INSTABILITY WILL GO AHD AND BEGIN TO DRY THE AREA SUN AFTN. PLENTY OF CU WILL FRM ONCE AGAIN SO PTLY SUNNY WILL BE THE BEST WE CAN HOPE FOR. UPPER HGTS AND SFC RDG BUILD RAPIDLY SUN NGT INTO MON. THIS WILL ALLOW TEMPS TO RCVR NICELY WITH MORE SUN ON MON. MORFORD && .LONG TERM (MON NIGHT-SAT)... THE WESTERN RIDGE/EASTERN TROUGH PATTERN CONTINUES THROUGH NEXT WEEK. A COLD FRONT MOVES THROUGH ON TUESDAY AFTERNOON...BRINGING WITH IT A CHANCE OF TSTORMS. THE FRONT GETS HUNG UP ALONG THE EAST COAST ON WEDNESDAY AS ANOTHER TROUGH DIGS INTO THE CENTRAL U.S.. ENERGY IN THE MOIST SOUTHWEST FLOW ALOFT WILL SEND WAVES OF LOW PRESSURE ALONG THE FRONT WED-SAT...SO WILL MENTION CHC POPS EACH DAY. JVA && .AVIATION... THE COOL NORTHWEST FLOW CONTINUES AS WEAK SHORT WAVES MOVE INTO CWA ON BACK SIDE OF UL TROF. THIS WILL CONTINUE TO PRODUCE MC VFR CONDITIONS INTO SUNDAY. RAIN NOT WIDESPREAD OR HEAVY ENOUGH TO INCLUDE A TEMPO ATTM. PRECIP AREA WILL SHIFT SLOWLY ENE INTO SUNDAY. SKIES CLEARED IN AVP THIS EVENING BUT MORE CLOUDS PUSHING SE BACK INTO NE PA. CHAMPNEY && .BGM WATCHES/WARNINGS/ADVISORIES... NY...NONE. PA...NONE. $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE UPTON NY 1000 AM EDT SAT AUG 7 2004 .SHORT TERM (THIS AFTERNOON)...UPDATING FORECAST FOR CLOUDS (MAINLY). ALTOSTRATUS IS TRAPPED BELOW SUBSIDENCE INVERSION SEEN ON 12Z KOKX SOUNDING AT AROUND 750MB. LATEST RUC INDICATED THAT THIS MOISTURE PREVAILS THROUGH THE DAY. IN ADDITION...SURFACE HEATING WILL HELP TO LIFT STRATO/ALTOCUMULUS THAT SPREADS OUT UNDER THE INVERSION. LOWERED TEMPS FOR MOST OF THE REGION. WARMEST TEMPS WILL BE FOUND OVER CT WHERE CLOUDS HAVE NOT FORMED YET. THUS A SUNNY...BECOMING MOSTLY CLOUDY AFTERNOON IN CT. HAVE DROPPED THE MENTION OF PCPN AS SOUNDING DO NOT SUPPORT ANY PCPN MAKING TO THE GROUND. SEE PREVIOUS DISCUSSION BELOW. && .LONG TERM...SEE PREVIOUS DISCUSSION BELOW. && . .PREVIOUS DISCUSSION... SHORT TERM (SATURDAY/SATURDAY NIGHT)... DEEP UPPER TROUGH AXIS JUST WEST OF THE REGION EARLY THIS MORNING WITH UPPER LOW CENTERED OVER SOUTHERN QUEBEC. TROUGH AXIS WILL PIVOT THROUGH THE REGION THIS AFTERNOON...BEFORE UPPER LOW PULLS NORTH INTO QUEBEC TONIGHT. THE BASE OF THE UPPER LOW AND THROUGH AXIS WILL SLIDE THROUGH THE REGION THIS AFTERNOON WITH 500 HPA TEMPS OF -20C...DECENT VORTICITY ENERGY...AND CYCLONIC FLOW. SHOWERS CURRENTLY OCCURRING UNDER VORT LOBE AND ALONG TROUGH AXIS OVER WESTERN NY AND CENTRAL PA. WITH THIS ENERGY...IN CONJUNCTION WITH CONVECTIVE TEMPS ONCE AGAIN AROUND 70...AND AFTERNOON ETA/GFS SOUNDINGS SHOWING SOME MOISTURE IN THE 850-700 HPA LAYER...CANT RULE OUT AN ISOLATED SHOWER OR SPRINKLE OVER NORTHERN SECTIONS FALLING FROM AFTERNOON HIGH BASED CU. HIGH TEMPS SHOULD AGAIN STRUGGLE INTO THE LOW TO MID 70S WITH 850 HPA TEMPS OF ONLY AROUND 6 C...A CONTINUED NW COLD ADVECTION FLOW...AND A MIX OF SUN AND CLOUDS IN THE AFTERNOON. THE UPPER LOW WILL BEGIN TO PULL NORTH OF THE REGION LATE TODAY...WHILE SURFACE LOW PRESSURE TO THE SOUTHEAST OF THE REGION WILL CONTINUE TO TRAVEL NORTH TOWARD THE CANADIAN MARITIMES. THIS WILL ALLOW FOR A DEEP...DRY...NW UPPER FLOW ENDING THE SHOWER THREAT. HIGH PRESSURE WILL BUILD SOUTHEAST OF THE REGION...ENDING THE COLD ADVECTION FLOW TONIGHT AS WINDS TURN MORE TO THE WEST. BUT WITH ANOMALOUSLY COOL AND DRY AIRMASS STILL OVER THE REGION...CLEARING SKIES...AND LIGHTENING WINDS...WILL GO 1 TO 2 DEGREES BELOW MAVS AGAIN TONIGHT. RECORDS ARE A FEW DEGREES COLDER THAN LAST NIGHT...SO ONLY EXPECTING ISOLATED RECORDS. LONG TERM (SUNDAY THROUGH FRIDAY)... UPPER TROUGH SLOWLY PULLS NORTHEAST OF THE REGION THROUGH MONDAY...WITH NW UPPER FLOW. HIGH PRESSURE SLIDES SOUTH OF THE REGION SUNDAY WITH A WSW FLOW HELPING TEMPS MODERATE TO ONLY A FEW DEGREES BELOW NORMAL. UPPER RIDGING BUILDS IN MONDAY...AS SURFACE HIGH PRESSURE MOVES OFFSHORE WITH A WARM FRONT MOVING NORTH OF THE REGION ON MONDAY. THIS WILL SPELL A WARMER AND MOISTER SW FLOW INTO THE REGION AND TEMPS AROUND NORMAL MONDAY AND TUESDAY. UPPER TROUGH MOVES INTO GREAT LAKES ON TUESDAY...WITH LOW PRESSURE INTO THE ST.LAWRENCE RIVER VALLEY AND ASSOCIATED COLD FRONT APPROACHING THE REGION AND INTERACTING WITH MARGINALLY UNSTABLE AND FAIRLY MOIST ENVIRONMENT TO PRODUCE SHRA/TSRA FOR LATE TUESDAY INTO WEDNESDAY MORNING. UPPER TROUGH REMAINS OVER THE GREAT LAKES THROUGH REMAINDER OF THE WEEK WITH PERIODIC SHORTWAVES ROTATING AROUND THE BASE. CONFIDENCE ON EXACT TIMING OF SHORTWAVES IS LOW...WITH MEDIUM-RANGE MODELS DIFFERING ON SOLUTIONS. NONETHELESS...SURFACE TROUGH LINGERS OVER REGION WEDNESDAY...SO WILL GO WITH AFTERNOON CHANCE SHRA/TSRA. THEREAFTER...UPPER TROUGH DEEPENS TO THE WEST OF THE AREA AND ATLANTIC RIDGE BUILDS TO THE EAST...WHILE SURFACE TROUGH LINGERS OVER THE AREA AND TROPICAL MOISTURE FEED DEVELOPS UP THE COAST. WILL KEEP CHANCE POPS THU AFTERNOON THROUGH EARLY SATURDAY AS MODELS WANT TO SPIN UP A COASTAL LOW AND ONSHORE FLOW AHEAD OF IT...AS UPPER TROUGH SLOWLY WORKS TO THE COAST. ************END OF PREVIOUS DISCUSSION ************************* && .AVIATION...CLOUDY THIS AFTERNOON (080BKN/OVC)...BUT VFR. CLEARING AFTER SUNSET. VFR ON SUNDAY AS WELL. && .MARINE...GENERALLY QUIET CONDITIONS THIS WEEKEND. SEAS WILL COME UP A BIT SUNDAY NIGHT INTO MONDAY IN RESPONSE TO FLOW TURNING SOUTHWEST...SETTING UP AN OPEN WATER FETCH AS OPPOSED TO OFF-SHORE FLOW. HOWEVER...SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. && .HYDROLOGY... DRY UNTIL TUESDAY AFTERNOON WITH SHRA/TSRA ACTIVITY. NO HYDROLOGIC PROBLEMS ANTICIPATED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NJ...NONE. NY...NONE. MARINE...NONE. && $$ TONGUE ny AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BUFFALO NY 949 AM EDT SAT AUG 7 2004 .SHORT TERM (THIS AFTERNOON)... SLACK GRADIENT OVER THE FORECAST AREA WITH HIGH PRESSURE TRYING TO BUILD IN FROM THE WESTERN LAKES. SURFACE FLOW STILL WEAKLY CYCLONIC...AND ANALYZING THE PRESSURE TO EVERY MB SHOWS A WEAK SURFACE TROUGH NEAR THE SOUTHERN ONTARIO/QUEBEC BORDER. THIS IS IN THE VICINITY OF COOLER CLOUD TOPS ON IR IMAGERY...ON THE WEST SIDE OF A WELL-DEFINED SHORTWAVE ON WATER VAPOR MOVING SSW. BOTH THE RUC AND THE ETA12 PROVIDE FOR AMPLE MID-LEVEL MOISTURE AND FAIRLY GOOD 700MB UVV OVER THE FORECAST AREA FOR THE AFTERNOON IN CONJUNCTION WITH THE MID-LEVEL WAVE MOVING SOUTH. MODIFYING THE 12Z BUF SOUNDING PROVIDES FOR CAPE IN THE HUNDREDS BUT A CONSIDERABLE AMOUNT OF SURFACE-BASED CIN TO OVERCOME WITH DEW POINTS ONLY FORECAST IN THE LOWER 50S AS A RULE. ETA MET POPS ARE NEAR THE LIKELY CATEGORY IN FAR WESTERN NEW YORK...AND FEEL THE CURRENT TRAJECTORY OF THE MID-LEVEL MOISTURE HAS THE POTENTIAL TO HAVE AS MUCH OF AN IMPACT ON FAR WESTERN NEW YORK AS AREAS FARTHER EAST. PLAN TO ESSENTIALLY CARRY SCATTERED SHOWERS THROUGHOUT THE FORECAST AREA THIS AFTERNOON UNDER CONTINUED MOSTLY CLOUDY SKIES. TEMPERATURE FORECAST ON TRACK AND HAVE CHANGED LITTLE...WITH MID TO UPPER 60S IN THE MAIN. SIMPLY LOOKING AT THE MOS GUIDANCE...RECORD LOW MAX OF 63 BOTH AT BUFFALO AND AT ROCHESTER FOR THE DAY...FROM 1903...HAS THE BEST POTENTIAL TO BE BROKEN AT ROCHESTER WITH 64S FOR MAXES FROM THE NGM AND ETA MOS AND ONLY 62 ON THE LAMP. CURRENT READINGS...THOUGH...ARE MORE IN LINE WITH THE GFS WHICH HAS A HIGH OF 67. REGARDLESS...HIGHS WILL BE WELL BELOW NORMAL. UPDATE WILL BE ISSUED BY 10 AM. && .PREVIOUS DISCUSSION... SHORT TERM (TODAY THROUGH MONDAY)...WEAK VORTICITY LOBES CIRCULATING AROUND THE UPPER LEVEL LOW...CURRENTLY CENTERED OVER NORTHERN NEW YORK STATE AND SOUTHERN QUEBEC...WILL CONTINUE TO PRODUCE A FEW SHOWERS ACROSS THE FA TODAY. SUPERIMPOSED ON THE OVERALL SYNOPTIC PATTERN...WE CONTINUE TO SEE SOME INFLUENCE FROM LAKE ONTARIO WHICH IS HELPING TO GENERATE A FEW MORE SHOWERS ACROSS THE GENESEE VALLEY. AS THE UPPER LOW MIGRATES SLOWLY TO THE EAST THIS AFTERNOON...THE SCATTERED SHOWERS WILL SHIFT INTO THE EASTERN FINGER LAKES AND NORTH COUNTRY...BUT WILL LEAVE IN CHANCE POPS FOR THE ENTIRE AREA TODAY AND NOT TRY TO GET TOO FANCY WITH THE TIMING OF THE PCPN WITH THIS TYPE OF PATTERN. AREA TEMPERATURES WILL STRUGGLE TO GET OUT OF THE 60S FOR THE FOURTH DAY IN A ROW...AN AMAZING STATISTIC FOR THE FIRST WEEK OF AUGUST. STRAY SHOWERS WILL LINGER FROM THE GENESEE VALLEY TO THE NORTH COUNTRY FOR AWHILE TONIGHT AS WRAP AROUND MOISTURE CONTINUES TO CIRCULATE BEHIND THE DEPARTING UPPER LEVEL LOW. THE REST OF THE AREA WILL SEE A GRADUAL DECREASE IN CLOUD COVER. SUNDAY WILL FEATURE A RETURN TO MORE NORMAL CONDITIONS AS THE CANADIAN RIDGE SETTLES INTO THE MID ATLANTIC STATES...SETTING UP A WEST TO SOUTHWEST FLOW ACROSS THE FA. TEMPERATURES WILL REBOUND INTO THE LOWER TO MID 70S. A 30 TO 40 KNOT LOW LEVEL JET WILL STRENGTHEN THE WARM AIR ADVECTION PATTERN SUNDAY NIGHT. THE GFS IS MUCH MORE AGGRESSIVE THAN THE ETA IN SETTING UP THE WARM AIR ADVECTION AND EVEN HINTS AT THE POSSIBILITY OF A CHANCE OF SHOWERS BY LATE SUNDAY. THE GFS OFTEN TIMES BRINGS THE PCPN IN TOO QUICKLY...BUT I WILL FOLLOW ITS TREND OF INCREASING CLOUDS FOR SUNDAY NIGHT AND MONDAY. I WILL INCLUDE A SLIGHT CHANCE OF SHOWERS IN THE WEATHER GRIDS FOR MONDAY...BUT WILL HOLD THE HIGHER CHANCE POPS OFF UNTIL MONDAY NIGHT WHEN THE NEXT UPPER LEVEL TROUGH DIGS INTO THE CENTRAL GREAT LAKES. LONG TERM (TUESDAY AND BEYOND)...THE SURFACE COLD FRONT THAT IS ASSOCIATED WITH THE GREAT LAKES TROUGH IS FORECAST TO PUSH THROUGH WESTERN AND CENTRAL NEW YORK TUESDAY MORNING. THE GFS SHOWS A NICE DRY SLOT BUILDING INTO THE AREA TUESDAY AFTERNOON THROUGH TUESDAY NIGHT...BUT A SECONDARY COLD FRONT ASSOCIATED WITH THE DIGGING UPPER LEVEL TROUGH WILL BRING A CHANCE OF SHOWERS AGAIN ON WEDNESDAY. DRIER AIR IS STILL ON TAP FOR THURSDAY BUT ANOTHER REINFORCING SHORT WAVE KEEPS A GENERAL TROUGHINESS OVER THE LOWER LAKES THROUGH LATE NEXT WEEK. SHOWERS CAN'T BE RULED OUT FOR FRIDAY. AVIATION... ONE MORE DAY UNDER THE INFLUENCE OF MASSIVE UPPER LOW WITH WESTERN NEW YORK LYING IN OUTER PERIPHERY MOST OF THE DAY AND INTO THE EVENING. WE WILL HAVE VARYING AMOUNT OF MID LEVEL CLOUD WITH AN OCCASIONAL SPRINKLE OR SHOWER...BUT THE VAST MAJORITY OF THE TIME WILL BE DRY SO WILL NOT INCLUDE IN ANY TEMPO GROUP. BEST CHANCE OF ANY SHOWERS WILL BE THIS AFTERNOON INLAND AND THIS EVENING SOUTH OF LAKE ONTARIO. CIGS AND VSBYS WILL GENERALLY REMAIN AT VFR LEVELS. SKIES WILL OPEN UP ON SUNDAY MORNING AS THE UPPER LOW PULLS FURTHER EAST BUT SOME CLOUDS WILL LINGER FROM KROC TO KART FOR AWHILE EVEN ON SUNDAY. WINDS WILL BE LIGHT AND INSIGNIFICANT. MARINE... CONTINUING WITH THE THREAT OF WATERSPOUTS FOR AWHILE TODAY ON LAKE ONTARIO...PARAMETERS MARGINAL BUT SLIGHTLY BETTER THAN FRIDAY ON THE YYZ WATERSPOUT NOMOGRAM AS GRADIENT IS WEAK ENOUGH IN CYCLONIC FLOW TO RESULT IN CONVERGENCE ALONG LAKESHORE. OTHERWISE...WINDS WILL BE 5 TO 15 KNOTS AS A RULE WITH THE NEXT GENEROUS INCREASE IN WIND SPEED LOOKING TO BE TUESDAY AND WEDNESDAY IN THE COLD ADVECTION BEHIND ANOTHER STRONG COLD FRONT IN THIS REPEATING AUTUMNAL PATTERN. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. $$ SHORT TERM...DJF PREVIOUS DISCUSSION...TJP/SAGE/SFM ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE 830 PM CDT SAT AUG 7 2004 .DISCUSSION...SATELLITE AND RADAR IMAGES INDICATE SHOWERS AND THUNDERSTORMS ACROSS THE WESTERN PORTIONS OF THE CWA HAVE DISSIPATED. WATER VAPOR AND RUC 200MB WIND STREAMLINE ANALYSIS INDICATES AN ANTICYCLONE ACROSS THE COASTAL BEND THIS EVENING WITH THE RUC 500MB HEIGHT ANALYSIS INDICATING THE SUBTROPICAL RIDGE ACROSS THE SOUTHWEST UNITED STATES AND NORTHERN MEXICO. BOTH THE RUC AND ETA40 500MB VORTICITY ANALYSES INDICATE A COUPLE OF VORT CENTERS MOVING AROUND THE PERIPHERY OF THE 500MB RIDGE. THIS PATTERN SHOULD CONTINUE TONIGHT INTO SUNDAY WITH THE SEABREEZE PROVIDING A FOCUS FOR LOW LEVEL CONVERGENCE SUN AFTERNOON. WILL GO AHEAD AND INCREASE POPS SUNDAY. AN OUTFLOW BOUNDARY FROM DIMINISHING CONVECTION OVER THE RIO GRANDE PLAINS THIS EVENING MAY MOVE INTO THE NORTHERN CWA TONIGHT BUT WILL LOWER POPS AS LOSS OF DAYTIME HEATING CONTINUES. && .MARINE...LIGHT ENE WINDS OF 5 TO 10 KNOTS AND 2 FEET SEAS PREVAIL OFFSHORE AT BUOY 020 THIS EVENING. THUNDERSTORM ACTIVITY IN THE VICINITY OF A STALLED FRONT OFFSHORE AND JUST TO THE NORTHEAST OF THE LOCAL WATERS WAS ISOLATED AND LESS THAN OVERLAND TODAY. SOME CONVECTION WILL CONTINUE OFFSHORE FOR THE NEXT 24 HOURS...BUT MOST WILL BE AWAY FROM THE LOWER TEXAS COASTAL WATERS. THE COASTAL WATERS FORECAST IN PLACE SEEMS TO HANDLE THE CURRENT SITUATION WELL...SO NO MAJOR CHANGES ARE PLANNED FOR THE NEXT REGULAR ISSUANCE LATER THIS EVENING. && .AVIATION...A SEA BREEZE DEVELOPED AGAIN THIS AFTERNOON...BUT A STATIONARY FRONT JUST TO THE NORTH OF THE CWA ALSO CONTRIBUTED INSTABILITY...AND A NUMBER OF SHOWERS AND THUNDERSTORMS MOVED SOUTHWEST FROM THAT BOUNDARY INTO THE NORTH AND WEST PORTIONS OF THE CWA. CONVECTION WILL TEND TO CONTINUE TO DEVELOP ALONG THAT BOUNDARY TOMORROW. FOR THE REST OF TONIGHT SKY CONDITIONS SHOULD REMAIN VFR. PRECIPITABLE WATER FROM THE 00Z SOUNDING INDICATES ANOTHER SEA BREEZE EVENT IS LIKELY FOR SUNDAY...WHEN MVFR CONDITIONS WILL BE POSSIBLE FOR A FEW HOURS IN THE AFTERNOON AS THE SEA BREEZE MOVES THROUGH. && .PREV DISCUSSION (ISSUED AT 235PM)...COLD FRONT NOW OVER THE NORTHERN GULF OF MEXICO WILL DISSIPATE. THIS WILL ALLOW A DRY AND STABLE WEATHER PATTERN TO CONTINUE FOR DEEP SOUTH TEXAS THROUGH THE BEGINNING OF NEXT WEEK WITH AFTERNOON SEA BREEZE SHOWERS AND THUNDERSTORMS. TEMPERATURES WILL CONTINUE TO BE ON THE WARM SIDE WITH AMPLE AMOUNT OF SUNSHINE. LIGHT TO MODERATE SOUTHEAST WINDS WILL PREVAIL THROUGH THE PERIOD. && $$ SYNOPTIC/GRIDS/PUBLIC...61 MARINE/AVIATION/MESO...54 THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 1140 AM CDT SAT AUG 7 2004 .AVIATION DISCUSSION... CURRENT DATA FROM KFWS 88D SHOWS SCT RW/TRW GENERALLY REMAINING TO THE WEST OF KMWL-KSEP-KBMQ. THIS ACTIVITY HAS BEEN LOCATED INVOF A STRONGER LLJ ACROSS WESTERN PORTION OF THE KDFW TRACON /PER DATA FROM KDYX 88D VWP/ AND WILL LIKELY HAVE A DIFFICULT TIME MOVING INTO THE SLIGHTLY DRIER AND MORE STABLE AIRMASS IN PLACE FURTHER EAST. IN CONCURRENCE WITH SHORT TERM ETA/RUC GUIDANCE...WE WILL NOT MENTION PRECIP IN ANY TAF ATTM. CIGS WILL REMAIN VFR AT TAF SITES THROUGH THE FORECAST PERIOD WITH SCT/BKN DECKS 9-12 KFT...AND INTERMITTENT PERIODS OF CIRRUS DEBRIS. SFC WINDS WILL GENERALLY REMAIN SELY FOR THE NEXT 24 HOURS...BUT MAY BACK TO E/ENE THIS AFTERNOON AS A WEAK MID-LEVEL SHEAR AXIS APPROACHES FROM THE NW. WIND SPEEDS WILL REMAIN AOB 12 KTS. 65/DD && .UPDATE... THERE WILL CONTINUE TO BE A CHANCE OF SHOWERS AND THUNDERSTORMS WEST OF I-35 THIS AFTERNOON...SO HAVE KEPT 20-30 PERCENT POPS THERE. WILL KEEP MOSTLY CLOUDY SKIES WEST OF I-35 AND PARTLY CLOUDY SKIES TO THE EAST. EAST TO SOUTHEASTERLY WINDS WILL CONTINUE TO BRING BRING UPPER 50S TO MID 60S DEWPOINTS ACROSS THE EASTERN TWO-THIRDS. #58 && .PREV DISCUSSION... 305 AM CDT SAT AUG 7 2004 GOING TO GO MORE CHANCE WORDING OUT WEST AND SCT CONVECTION IS CONTINUING TO EXPAND EWD. WILL MATCH UP WITH SURROUNDING OFFICES PER RADAR TRENDS FOR TODAY. MAY COOL HIGHS DOWN OVER WRN ZONES MORE THAN EXPECTED AS WELL AS CLOUD COVER SHOULD HOLD MORE OVER THIS REGION. 230 AM CDT SAT AUG 7 2004 MCS CONTINUES PROPAGATING SWD OVER WC TX AS OF 08Z...ALONG ERN PERIPHERY OF 850-700 MB THETA-E AXIS ANCHORED OVER FAR W TX...WHERE ELY SFC UPSLOPE FLOW IS FOCUSING SOME LIFT AS WELL. SOME SCT SHOWERS/STORMS HAVE DEVELOPED ON RESIDUAL BOUNDARY TO THE NE OF THIS COMPLEX NEAR KCDS AND IN SW OK WITH TRAJECTORY TO THE SE. WITH TIGHT THETA-E GRADIENT TO REMAIN SITUATED OVER FAR WRN ZONES TODAY AND CONTINUED E/SELY FLOW FEEDING INTO THIS AREA ENHANCING SOME WEAK LIFT...FELT SLIGHT CHANCE SHOWERS/STORMS WAS PRUDENT. ALSO...ANVIL BLOW OFF FROM CIRRUS...COMBINED WITH THERMAL FIELDS STAYING RELATIVELY STAGNANT SHOULD KEEP REGION RELATIVELY COOL FOR AUGUST...BUT WE/LL TAKE IT! MOISTURE AXIS RETREATS NWWD BEGINNING TONIGHT AND THROUGH SUNDAY. MID LVL RIDGE ANCHORED OVER FAR W TX EXPANDS EWD SOMEWHAT AS WELL...RESULTING IN A GRADUAL WARM UP AS MS VALLEY POLAR HIGH CENTER THAT BROUGHT RELIEF TO N TX...RETREATS EWD AND FLOW RETURNS FROM THE S/SE...THOUGH LIGHT. NEXT SURGE OF CP AIR POOLED UP IN CANADA BEGINS SURGING S/SEWD INTO THE NRN ROCKIES/PLAINS LATE MON INTO TUES...AS UPPER FLOW IN BETWEEN HUDSON BAY LOW-W COAST UPPER RIDGE REMAINS SUPPORTIVE IN DRIVING THESE AIRMASS INTO THE CENTRAL CONUS. HELD ONTO LOW POPS BEGINNING MON NIGHT MAINLY FROM ANY OUTFLOW DEVELOPED FROM MCS EXPECTED TO DEVELOP OVER NW TX/OK...THOUGH FEEL MAIN CRUX OF LIFT/COOL DOWN FROM COLD FRONT AND ENHANCING NW FLOW ALOFT TO COME WED AND THURS... POSSIBLY LINGERING INTO FRI IF FRONT STALLS NEAR SRN ZONES LIKE GFS ADVERTISES...THOUGH ECWMF SUGGESTS FROPA ALL THE WAY DOWN TO THE UPPER TX COAST FRI. BEING THAT IT/S AUGUST...LEANING WITH THE GFS. 05 && .PRELIMINARY TEMPS/POPS... DALLAS-FT. WORTH, TX 89 70 93 73 / 0 0 0 0 WACO, TX 91 69 94 73 / 0 0 0 0 PARIS, TX 87 65 92 68 / 0 0 0 0 DENTON, TX 88 68 93 71 / 0 0 0 0 MCKINNEY, TX 88 68 93 71 / 0 0 0 0 DALLAS, TX 90 71 93 74 / 0 0 0 0 TERRELL, TX 89 67 93 71 / 0 0 0 0 CORSICANA, TX 91 68 93 72 / 0 0 0 0 TEMPLE, TX 92 70 94 73 / 20 0 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 935 AM CDT SAT AUG 7 2004 .UPDATE...PER MSAS/RADAR/SATELLITE...THE WEAK FRONTAL BOUNDARY IS CURRENTLY LOCATED FROM GOLIAD TO ROCKPORT AND EXTENDING OFFSHORE TO BEYOND 60NM SE OF PORT ARANSAS. THE BDRY IS SLOWLY DRIFTING SW. A VORT MAX ASSOCIATED WITH CONVECTION MOVG INTO THE NW PORTION OF EWX'S CWA...IS PROGD TO MOVE SLOWLY S THEN SW THROUGH THE AFTERNOON. THE VORT MAX ASSOCIATED WITH THE CONVECTION OFFSHORE IS PROGD TO ALSO MOVE SW ALONG THE COAST. AGREE WITH PREVIOUS SHIFT THAT CONVECTION SHOULD INCREASE FARTHER INLAND THROUGH THE AFTERNOON GIVEN THE 2+INCH PWAT'S...APPROACHING VORT MAX FROM THE N AND SFC CONVERGENCE ALONG THE BDRY...AND AN UNSTABLE ENVIRONMENT PER THE SOUNDING. A COUPLE OF OPPOSING FACTORS PER THE PREFERRED GFS WILL BE ISENTROPIC DOWNGLIDE ACROSS THE WRN CWA AND FCSTD CONFLUENCE/SUBSIDENCE IN THE UPPER LEVELS BY THIS AFTERNOON. THE RUC IS INDICATING AN INCREASE IN PRECIP ALONG THE COAST LATER THIS MORNING THEN LESSER PRECIP VALUES DRAPED ACROSS THE CENTRAL AND SE CWA EXTENDING OFFSHORE TO THE SE BY NOON. WILL CONTINUE WITH 30 POPS INLAND AND INCREASE POPS TO 30 ALONG THE COAST. && .PREVIOUS DISCUSSION... .SHORT-TERM (TODAY THROUGH SUNDAY)...PER MSAS ANALYSIS OF SFC WINDS AND SFC THETA-E...WEAK FRONTAL BOUNDARY STRETCHES FROM NEAR HALLETTSVILLE SOUTHEAST TO NEAR BAY CITY AND OUT INTO THE GULF NEAR BOUY 42019. FRONTAL BOUNDARY WILL CONTINUE TO DRIFT SOUTHWEST THRU THE MORNING. GFS HAS A BETTER HANDLE ON THE WIND/DEW POINTS AND PW FIELDS VS THE ETA. GOES SOUNDER SHOWS 2" PW POOLED ACROSS THE CRP MARINE ZONES INTO THE COASTAL BEND AND UP THRU S-CNTRL TX. MSAS REVEALS MOISTURE CONVERGENCE TAKING PLACE ACROSS THE NEAR AND OFFSHORE WATERS AND CRP 88D SHOWING ISOL CONVECTION DEVELOPING IN THIS LOCATION. WILL TREND FORECAST THRU THE MORNING HOURS TOWARDS THE GFS/RUC WHICH SHOWS ISOL/SCT CONVECTION OCCURRING AHEAD OF THE WEAK FRONT...WHERE BEST MOISTURE CONVERGENCE TAKING PLACE. ISOL/SCT CONVECTION SHOULD SHIFT INLAND DURING THE AFTERNOON AND EARLY EVENING...FAVORING THE CNTRL AND RIO GRANDE PLAINS COUNTIES...WHERE GFS SHOWING PW POOLING AND INTERACTING WITH ANY REMAINING FRONTAL BOUNDARY OR MESOSCALE OUTFLOW BOUNDARIES FROM EWX CWA. MCS OVER THE LUB/SJT AREA INDICATING SOME SIGNS OF WEAKENING AS IR SAT SHOWS WARMING CLOUD TOPS AND WILL BE NOT BE A DIRECT IMPACT ON THE CWA. WEAK CONVERGENCE OVER THE WATERS EARLY TOMORROW MORNING MAY LEAD TO AN ISOL RW OR TWO. FRONTAL BOUNDARY WASHES OUT TOMORROW. PW REMAINS POOLED ACROSS THE INLAND COUNTIES WITH DRIER AIR FILTERED IN ACROSS THE NE COUNTIES AND NRN WATERS. WILL FORECAST ISOL TO LOW END CHC POPS FOR INTERIOR SECTIONS OF THE CWA FOR ANY AFTERNOON CONVECTION DEVELOPING ALONG SEA BREEZE. && .LONG-TERM (SUNDAY NIGHT THROUGH FRIDAY)...GFS/NOGAPS/CANADIAN MODELS PROG THE UPPER RIDGE TO RETROGRADE DURING THE PERIOD... RESULTING IN A WEAKNESS IN THE UPPER HEIGHTS OVR THE CWFA. LOCAL FORCING/MSTR/INSTABILITY WL RESULT IN ISOLD CONVECTION SUNDAY EVENING/MONDAY AND TUE AFTNS. MODELS PROG AN UPPER DISTURBANCE TO MOVE ACROSS THE PLAINS WITH THE RESULTING FRONTAL BNDRY APPROACHING THE CWFA LATE WED. WL ISSUE SLIGHTLY HIGHER POPS FOR WED AFTN/EVENING OVR THE NRN CWFA OWING TO THE EXPECTED PROXIMITY OF THE FRONT AND CONVECTION FROM A PSBL UPSTREAM MCS THAT MAY ENTER THIS AREA. EXPECT THE FRONT TO STALL IN THE VICINITY AND SERVE AS A TRIGGER FOR CONVECTION THURSDAY/FRIDAY. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 95 74 96 75 / 20 05 20 10 VICTORIA 92 71 94 73 / 30 05 10 10 LAREDO 102 79 102 79 / 30 30 20 20 ALICE 98 73 99 74 / 30 10 30 20 ROCKPORT 93 78 93 78 / 20 10 10 00 COTULLA 98 75 99 76 / 30 30 30 20 && .CRP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE 81 PREVIOUS DISCUSSION 76...SHORT-TERM 87...LONG-TERM tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 1047 AM EDT SAT AUG 7 2004 WILL OPT TO UPDATE THE GOING FCST TO MAKE SOME CHANGES TO MOSTLY THE FIRST PERIOD. .SYNOPSIS... HI PRESS TO REMAIN ACRS THE GREAT LKS REGION...WITH SOME SFC CYCLONIC FLOW ACRS THE FA...TODAY AND TONITE. UPR TROF TO REMAIN ACRS THE FA AS WELL TODAY AND TONITE. .SHORT TERM (THROUGH TONITE)... 06Z TAQ RUC/09-11Z 20KM "DEVELOPMENT" RUC SHOW TEMPS TO GET UP INTO THE M60S-M70S TODAY WITH NORTHERLY SFC WINDS AT 5-15 KTS. T1MAX TEMPS ARE 65-70F TODAY AND LOOK A TAD BETTER THAN RUC TEMPS BASED ON MESONET OBS. FEW TWEAKS TO FIRST PERIOD TEMPS/WINDS BASED ON THIS DATA. SOME LOW-LVL MSTR TO CONT TO AFFECT THE FA TODAY AND TONITE. PW VALUES ACRS THE FA LOOK TO BE 0.6-0.9" TODAY AND TONITE. CAPES TO BE AOB 500 J/KG ACRS THE FA. RUC SHOWS MOCLDY SKIES ACRS THE FA TODAY WITH SCT PCPN. WITH CAPES HIR THAN THEY WERE YESTERDAY AND WET-BULB ZERO HTS OF 6-7 KFT...WOULD NOT BE SURPRISED TO SEE AN ISOLATED LTG STRIKE ACRS THE FA WITH SOME SMALL HAIL TODAY. BUFCAN/88D MOSAIC SHOWS SOME SCT PCPN ACRS THE FA ATTM. WK H85 CAA TO TAKE PLACE ACRS THE FA TODAY AND TONITE. LOW-LVL LAPSE RATES TO BE HI ACRS THE FA THIS AFTERNOON. SOME MID-LVL MSTR TO AFFECT THE FA TODAY AND TONITE. WILL HANG ONTO SCT/CHC POPS ACRS THE FA TODAY. WILL OPT TO USE THE STF TO HIGHLITE ANY LTG/SMALL HAIL THAT ACTUALLY HAPPENS ACRS THE FA TODAY. BEST INSTABILITY LOOKS TO BE EAST OF THE FA TODAY. REST OF CHANGES TO THE GOING FCST COSMETIC. .HYDROLOGY... 24-HR QPE ACRS THE FA LOOKS TO BE BLO 0.25" ACRS MUCH OF THE FA... WITH SOME ISOLATED AMTS AROUND 0.75" IN THE MTNS AND ALONG LK CHAMP (IN WHAT APPEARED TO BE SOME ENHANCEMENT ALONG THE LK YESTERDAY EVENING). MESO-ETA BUFR DATA HINTING THAT THIS MAY HAPPEN AGAIN LATER TODAY AND WILL HIGHLITE THAT AS WELL IN THE STF IF IT TAKES PLACE. WRK ZONES AVAILABLE. ALL FINAL PRODUCTS ASAP. MURRAY .PREV DISCUSSION...FROM 442 AM EDT .SHORT TERM (TODAY THROUGH SUNDAY)... CLOSED UPPER LOW TO BE OVER THE FORECAST AREA TODAY WITH MOSTLY CLOUDY SKIES AND A CHANCE OF SHOWERS TODAY AND TONIGHT. CLOSED UPPER LOW TO MOVE NORTHEAST INTO THE CANADIAN MARITIMES ON SUNDAY ...HOWEVER MODELS SHOW SEVERAL SHRTWVS WILL ROTATE AROUND THE CLOSED UPPER LOW AND MOVE ACROSS THE REGION ON SUNDAY...SO HAVE KEPT A CHANCE OF SHOWERS IN THE FORECAST FOR SUNDAY. GFS MAV MOS GUIDANCE MAX TEMPS FOR TODAY AND SUNDAY LOOK A BIT TOO WARM...ESPECIALLY IN THE CHAMPLAIN VLY AND THE ST LAWRENCE VLY...SO HAVE GONE SEVERAL DEGREES BELOW THIS. NGM MOS MAX TEMPS LOOK IN THE BALL PARK FOR TODAY AND SUNDAY. .LONG TERM (MONDAY THROUGH FRIDAY)... RIDGE OF HIGH PRESSURE AT THE SURFACE AND ALOFT TO BUILD INTO THE REGION ON MONDAY FOR MOSTLY SUNNY SKIES AND TEMPERATURES NEAR NORMAL. WARM FRONT TO APPROACH THE REGION LATE MONDAY NIGHT...WITH GFS MODEL BRINGING IN PRECIPITATION TO NORTHERN NEW YORK ZONES LATE MONDAY NIGHT...WHILE ETA AND CANADIAN SEF MODELS HOLD OFF ON PRECIPITATION TIL AFTER 12Z ON TUESDAY. CURRENT FORECAST IS DRY FOR MONDAY NIGHT... AND GIVEN DIFFERENCES IN THE MODELS WILL NOT MAKE ANY CHANGES TO THE MONDAY NIGHT FORECAST ATTM. HAVE NOT MADE ANY CHANGES TO THE FORECAST BEYOND TUESDAY. .AVIATION... WDLY SCT SHWRS WL INCRS IN CVRG LTR THIS MRNG AND AFTN AS DAYTIME HEATING ENHANCES INSTBY WITH COLD POOL ALF. EXPECT MAINLY VFR CONDS THRU THE PD WITH BKN-OVC SC/AC...BUT OCNL MVFR CONDS PSBL ERLY THIS MRNG AND IN ANY SHWRS DURG THE DAY. DIURNAL SHWR ACTIVITY SHOULD GRADUALLY DECREASE IN CVRG TNGT. SHORT TERM/LONG TERM...WGH AVIATION...KJC .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ vt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 300 PM CDT SAT AUG 7 2004 .SHORT TERM...TONIGHT THROUGH MONDAY NIGHT... CURRENT DATA ANALYSIS SHOWING SURFACE LOW PRESSURE CENTERED OVER SOUTH DAKOTA. A WARM FRONT EXTENDS FROM THIS LOW INTO WESTERN MINNESOTA. WARM ADVECTION AT THE SURFACE IS CONVERGING ON THIS BOUNDARY CAUSING SOME CONVECTION THAT EXTENDS FROM NORTH OF KMSP TO NEAR KRGK. WATER VAPOR LOOP ENDING AT 1931Z SHOWING THE CENTER OF THE MESOSCALE CONVECTIVE VORTEX /MCV/ THAT PASSED THROUGH THE FORECAST AREA THIS MORNING CENTERED OVER CENTRAL WISCONSIN. THIS WILL CONTINUE TO MOVE EAST OUT OF THE FORECAST AREA. TO THE WEST...A DISTURBANCE WAS MOVING THROUGH MONTANA...CAUSING SOME THUNDERSTORMS IN A DRY AIRMASS. THIS DISTURBANCE WILL CONTINUE TO MOVE SOUTHEAST IN THE MEAN 500 MB FLOW...MOVING THROUGH THE FORECAST AREA SUNDAY. MAIN SHORT TERM FORECAST IS TEMPERATURES/TIMING OF CONVECTION. FORECAST CONFIDENCE IS MEDIUM. FOR THIS EVENING...THINK THE CONVECTION ONGOING OVER EASTERN MINNESOTA WILL CONTINUE ITS TREND EASTWARD. ALTHOUGH IT IS MOVING INTO A MORE STABLE ENVIRONMENT...IT IS BEING FORCED BY LOW LEVEL MOISTURE TRANSPORT. THIS IS CAPTURED WELL BY THE ETA/RUC MODELS. THIS PERSISTS INTO THE EVENING...THEN INCREASES ALONG THE WARM FRONT AS IT MOVES FURTHER NORTHEAST. THIS SHOULD PRODUCE MORE CONVECTION OVER THE NORTHERN PORTION OF THE FORECAST AREA TONIGHT. IN FACT...THE ISENTROPIC UPGLIDE CONTINUES ALL THE WAY SOUTH INTO NORTHERN IOWA. THE LACK OF MOISTURE SHOULD PROHIBIT DEVELOPMENT THAT FAR SOUTH...HOWEVER...STILL FEAR THE DRY AIR MAY BE OVERCOME. WILL STICK TO A DRY FORECAST WHICH IS THE MOST PLAUSIBLE OUTCOME AT THIS TIME. WILL DROP TEMPERATURES A FEW DEGREES TONIGHT GIVEN THE COOLER THAN EXPECTED HIGHS TODAY. THE DISTURBANCE OVER EASTERN MONTANA WILL MOVE EAST INTO OUR REGION SUNDAY. GFS/ETA SLOWER THAN PREVIOUS RUNS. A LOOK AT THE 18Z ETA SUGGESTS FURTHER SLOWING. SLOWED TIMING OF FRONTAL PASSAGE BY 3-6 HOURS. SBCAPES OF 3000-400 J/KG ARE EXPECTED ALONG/AHEAD OF THE FRONT. THESE CAPES ALONG WITH WETBULB ZERO HEIGHTS NEAR 10 KFT AGL SHOULD BE ENOUGH TO PRODUCE SEVERE HAIL. SHEAR /0-6 KM AND 0-3 KM/ IS MINIMAL SO THINK WE WILL SEE UNORGANIZED PULSE STORMS THAT ARE SOMEWHAT UNORGANIZED. HOWEVER...THE FRONT MAY PRODUCE ENOUGH LINEAR FORCING TO ORGANIZE THE CONVECTION INTO A LINE. WILL WAIT AND SEE. THE LOW/SURFACE COLD FRONT MOVES THROUGH THE FORECAST AREA BY MONDAY MORNING. COOL NORTHERLY/COLD ADVECTION WILL BRING IN COOLER AIR TO THE REGION. THE ONLY CONCERN FOR CLOUDS AND PRECIPITATION IS BEING IN THE CYCLONIC FLOW. THIS IS MOST FAVORABLE ACROSS THE NORTHEASTERN PORTIONS OF THE FORECAST AREA /CENTRAL WISCONSIN/. .LONG TERM...TUESDAY THROUGH SATURDAY... THE LONGWAVE 500 MB PATTERN INCREASES IN AMPLITUDE AND REMAINS AMPLIFIED THROUGHOUT THE PERIOD. THIS IS THE RESULT OF A STRONG NEGATIVE HEIGHT ANOMALY DEVELOPING OVER ONTARIO BY MID-WEEK. THIS WILL INCREASE THE CHANCE OF LIGHT PRECIPITATION AS UPPER LEVEL DISTURBANCES ROTATE ABOUT THIS FEATURE. IT WILL ALSO CAUSE TEMPERATURES TO REMAIN WELL BELOW NORMAL THROUGHOUT THE PERIOD. THE MAIN FORECAST CHALLENGE IS RESOLVING THE PRECIPITATION CHANCES AND AMOUNT OF COOLING THAT WILL TAKE PLACE. FORECASTER CONFIDENCE IS MEDIUM. ETA/GFS/ECMWF SHOW SOME CONSENSUS FOR THE PERIOD. THE MAIN DIFFERENCE IF WHERE THE CENTER OF THE NEGATIVE HEIGHT ANOMALY WILL BE. THE ECMWF IS MUCH FURTHER NORTH WHILE THE OPERATIONAL GFS AND ITS ENSEMBLE MEMBERS FAVOR A CENTRAL LOCATION OVER SOUTHERN ONTARIO. THE DEEPENING 500 MB NEGATIVE HEIGHT ANOMALY NEAR THE NORTHERN LAKES IS FURTHER SUPPORTED BY THE ETA...WHICH IS THE STRONGEST...CLOSING OFF A LOW BY 18Z TUESDAY OVER SOUTHERN ONTARIO. WILL FAVOR A CENTRAL LOCATION OVER SOUTHERN ONTARIO. GFS PVU/400-200 MB POTENTIAL VORTICITY ADVECTION SUGGESTS THAT A SIGNIFICANT DISTURBANCE WILL MOVE THROUGH TUESDAY. THE FAVORABLE CURVATURE/AGEOSTROPHIC WIND DIVERGENCE IS NORTH OF THIS FEATURE. THIS WILL CAUSE THE PRECIPITATION ASSOCIATED WITH THIS FEATURE TO MOVE THROUGH WEDNESDAY. A SECONDARY DISTURBANCE MOVES DOWN AND ACROSS THE FORECAST AREA RIGHT BEHIND THE FIRST SYSTEM. THIS WILL AGAIN CAUSE ADDITIONAL PRECIPITATION INTO FRIDAY. AT THIS TIME...CHOSE TO FORECAST THUNDERSTORMS. THE DEPTH OF THE PVU AS WELL AS THE LOW LEVEL INSTABILITY SHOULD SUPPORT THUNDERSTORMS. THE 850 MB TEMPERATURES SHOW THE COLDEST PUSH OF AIR FRIDAY MORNING. THE FORECAST 850 MB TEMPERATURES ARE ONLY 3C. GIVEN THAT WE SHOULD REMAIN IN NORTHWEST FLOW THROUGHOUT MUCH OF THE WEEK...WILL KEEP TEMPERATURES A FEW DEGREES BELLOW NORMAL AND REFINE THE DETAILS AS IT NEARS. && .ARX...WATCHES/WARNING/ADVISORIES... IA...NONE. WI...NONE. MN...NONE. && $$ KRC wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 500 AM EDT SUN AUG 8 2004 .DISCUSSION... MAIN FCST CONCERNS ARE SHRA/TSRA TIMING/COVERAGE/STRENGTH TODAY THROUGH MON. WV IMAGERY AND RUC ANALYSIS INDICATED PERSISTENT MID LVL LO OVER NRN NEW ENGLAND WITH UPSTREAM RDG OVER NRN ONTARIO. TO THE WEST...COMPACT/VIGOROUS MID/UPR LVL LOW WAS LOCATED OVER NE MT. WEAK/SHEARED SHRTWV INTO W LK SUPERIOR AND W UPR MI WAS MAKING LITTLE EASTWARD PROGRESS AT IT ENCOUNTERS CONFLUENT ZONE TO THE EAST. THE SHRTWV COMBINED WITH PERSISTENT 300K-310K ISENTROPIC LIFT AHEAD OF WARM FRONT INTO SRN MN...SUPPORTED MID CLOUDS OVER THE W HLF OF UPR MI AND BAND OF -SHRA OVER NW WI. NO TSRA...PER LIGHTNING DETECTION...SINCE 00Z/SUN WITH THIS PCPN BAND AS MAIN AREA OF CONVECTION WAS LOCATED OVER SD...VCNTY MORE SIGNIFICANT LOW LVL THETA-E RDG AND UPR LVL DIFFLUENCE/DIV AHEAD OF THE MT SHRTWV. CONVECTION INTO S MN WAS DEVELOPING VCNTY SFC WARM FRONT. TODAY...WAA/ISENTROPIC LIFT PATTERN FCST TO MAKE SLOW PROGRESS INTO THE W HLF OF UPR MI AS MID LVL LOW MOVES THROUGH ND AND THE SFC AND MID LVL RDG AXIS AND ASSOCIATED CONFLUENT ZONE SLIDES TO THE EAST. EVEN THOUGH THE AIRMASS IS NOT AS DRY AS SATURDAY...THE DRIER GFS WITH LOWER POPS/QPF WAS PREFERRED...GIVEN RADAR TRENDS AND RELATIVELY WEAK SUPPORT FOR PCPN TODAY. ALTHOUGH TSTMS MAY BE SCARCE...MENTION OF ISOLD TSRA WAS RETAINED AS MOISTURE/INSTABILITY FROM THE PLAINS TO THE UPR MS VALLEY EDGES EASTWARD. HOWEVER...LIMITED INSOLATION THROUGH THICKENING MID CLOUDS AND DEWPOINT RECOVERY TO NEAR 60F WOULD ONLY GIVE MODEST MLCAPE OR MUCAPE VALUES IN THE 300-700 J/KG RANGE. TONIGHT...MOISTURE AXIS WITH PWAT TO AROUND 1.5 INCHES AND FAVORABLE DYNAMICS WITH GOOD LOW LVL THETA-E ADVECTION...300K-305K ISENTROPIC LIFT AIDED BY UPR LVL DIV/DIFFLUENCE AHEAD OF THE MID LVL LOW WILL SUPPORT NMRS SHRA/TSRA PROGRESSING FROM W UPR MI DURING THE EVENING INTO THE E CWA AFT 06Z. WHILE ONLY MINIMAL DIFFERENCES WITH THE HEIGHT FIELDS NOTED (ETA A BIT FARTHER SE WITH THE H5 LOW) THE ETA 300K-305K DEPICTION OF LESS AGGRESSIVE POSITION OF 900-850 FRONT AND MOISTURE SURGE (H8 TEMPS NEAR 11C COMPARED TO 14C WITH THE GFS) APPEARED MORE REASONABLE. SO...LOWER MUCAPE VALUES EXPECTED COMPARED TO THE GFS WHICH SHOWS VALUES AROUND 1200 J/KG. WITH STRONG DYNAMICS...EMBEDDED TSRA STILL EXPECTED BUT WITH 0-6KM SHEAR ONLY NEAR 25 KT AND ONLY MODEST LOW LVL SHEAR (H8 WIND TO 20-25 KT) ONLY MINIMAL SVR THREAT EXPECTED. BEST CHANCE FOR LARGER HAIL OR HIGHER WINDS WOULD BE OVER THE FAR WEST DURING THE EVENING...PER SPC OUTLOOK...WHICH WOULD BE CLOSER TO THE LOW LVL THETA-E RDG BEFORE IT SLIDES TO THE SE. MON...TEMPORARY DRYING POSSIBLE AS THE MAIN MOISTURE AXIS LIFTS TO THE ENE. HOWEVER...WITH THE APPROACH OF THE MID LVL LOW WITH STEEPENING LAPSE RATES (H5 TEMP TO AROUND -14C) AND CONTINUED 700-300 QVECTOR CONV SCT TO NMRS SHRA EXPECTED WITH SOME TSRA. MON NIGHT...TSRA CHANCES CONTINUE OVER THE E...WHERE INSTABILITY LINGERS...PER ETA/GFS. OTHERWISE...LESS FAVORABLE QG DYNAMICS PREVAIL WITH MID LVL LOW TO THE N. PCPN CHANCES WILL INCREASE OVER THE W LATE AS SFC TROF AXIS MOVES IN. TUE...AS TRAILING SINKS SOUTHEAST WITH QVECTOR CONV INCREASING AND SFC TROF SLIDES THROUGH WITH CYCLONIC LOW LVL FLOW IN ITS WAKE...EXPECT CLOUDY...COOL AND BREEZY FALL-LIKE DAY WITH AREAS OF LIGHT RAIN...ESPECIALLY NORTH. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 255 AM EDT SUN AUG 8 2004 .AVIATION... WOULD EXPECT SOME FOG AT IPT...AND FOR A BRIEF TIME AT THE OTHER SITES THIS AM...BUT CLDS AND SOME WIND KEEPING FOG IN CHECK FOR NOW. OTHERWISE VFR CONDITIONS TODAY. MAINLY VFR CONDITIONS TONIGHT...BUT MAY BE SOME FOG BETWEEN 09Z AND 12Z...BUT EXPECT A SLIGHT BREEZE FROM THE W-NW...THUS NOTHING REAL DENSE. && .SHORT TERM (TODAY THROUGH TUESDAY)... WATER VAP IMAGERY SHOWING UPPER LO BEGINNING TO LIFT OUT OF NEW ENGLAND...WHILE WEAK S/WV DROPS SEWRD THRU OHIO VALLEY. LATEST RUC SUGGESTS STRATOCU OVER N MTNS LIFTS OUT BY 12Z...LEAVING ENTIRE FA MSUNNY BY LATER THIS MORNING. WESTERLY FLOW WILL ADVECT MILDER AIR FROM THE GRT LKS TODAY...WHERE HIGHS WERE CLOSE TO 80F YESTERDAY. OUR 850 TEMPS NR 11C SUGGEST SIMILAR READINGS IN THE VALLEYS...MINUS A FEW DEG IN MTNS. CLEAR SKIES/CALM WIND SHOULD ONCE AGAIN RESULT IN CHILLY READINGS TONIGHT. HOWEVER...WARMER MORE HUMID AIR RETURNS MONDAY AS SFC HIGH SLIPS OFF THE EAST COAST. POTENT S/WV...CURRENTLY OVER NORTHERN PLAINS...IS PROGGED TO PUSH EASTWARD OVER THE NEXT 72HRS...PUSHING A COLD FRONT THRU CENTRAL PA ON TUESDAY. INITIAL INDICATIONS FROM MODEL SOUNDINGS DO NOT SHOW A SIGNIFICANT SVR WX THREAT. ONLY MARGINAL INSTABILITY AND SHEAR. HOWEVER...A ROUND OF SHWRS/STORMS SEEMS A GOOD BET ALONG AND AHEAD OF FRONT. && .LONG TERM (TUESDAY NIGHT THROUGH SATURDAY)... 00Z MREF SUGGESTS THAT UPPER TROUGH SHARPENS OVER THE MIDWEST DURING MIDWEEK...CAUSING FRONTAL BOUNDARY TO HANG UP OVER THE APPALACHIANS. WILL KEEP SHWRS/STORMS IN FCST THRU THURSDAY...AFTER WHICH SOMEWHAT DRIER BUT STILL UNSETTLED WX FOR FRI/SAT AS UPPER TROUGH MOVES OVER THE AREA. WILL HAVE TO WATCH FOR FLOODING POTENTIAL AS SEVERAL ENSEMBLE MEMBERS ALREADY PRODUCING OVER ONE INCH OF RAIN WITH WAVE RIDING UP FRONT DURING WED/THURS. && .CTP WATCHES/WARNINGS/ADVISORIES... PA...NONE. && $$ AVIATION...MARTIN SHORT TERM/LONG TERM...FITZGERALD pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 400 AM CDT SUN AUG 8 2004 .DISCUSSION...FORECAST FOCUS ON PRECIPITATION TODAY AND MONDAY ...THEN TEMPS WITH COOLING TREND THIS WEEK. WEAK SHRT WV AND WAA PATERN STILL TRIGGERING SOME SCT SHRA OVER CNTRL WI WHICH WILL DRIFT SE THRU NE SECTIONS OF CWA THIS AM. ATTENTION TURNS TO MORE WIDESPREAD SHRA/TSTMS THIS AFTN EVE AS RUC ANALYSIS DEPICTS ANOTHER WEAK SHRT WV AHEAD OF MAIN 500 MB LOW THAT IS TIMED INTO WRN WI LATE THIS AFTN. WILL KEEP CHC TSTMS FOR WRN CWA FOR THIS AFTN WITH SFC MOISTURE CONVERGNCE INCREASING ON STRENGTHENING SW FLOW AHEAD OF APPCHG TROF/COLD FNT. TSTMS LIKELY TNT AS SFC DEW PTS INCREASE TO LOWER TO MID 60S ALONG/AHEAD OF FRONT AS IT WORKS INTO WRN WI BY 12Z MON. 06Z RUNS ARE SLOWING THE FRONT SOME FROM PREV RUNS BUT SHOULD EXIT ERN WI AROUND/SHRTLY AFTER 00Z TUE...KEEPING PCPN IN FCST FOR THE DAY MONDAY AS BEST DYNAMICS FM CLOSED LOW WORK ACROSS RGN. HAVE ADDED AFTN SHRA TO NRN COUNTIES FOR TUE AS CAA BEHIND FIRST WAVE DROPS 850 TEMPS INTO THE 0 TO +2C RANGE BY WED MORNING...AND SOME CVA ASSOC WITH SECOND WAVE REACHES NRN PORTIONS OF CWA. DYNAMICS FROM THIS SHRT WAVE AND INSTABILITY FROM COLD CYCLONIC FLOW ALOFT BRING A BETTER CHC FOR SHRA ON WED...WITH ANOTHER SHRT WAVE EXPECTED ON THU KEEPING CHC PCPN IN FCST AND REINFORCING BELOW NRML TEMPS THRU THE END OF THE WEEK. && .MKX...WATCHES/WARNINGS/ADVISORIES...NONE $$ REM wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 1000 AM EDT SUN AUG 8 2004 .SHORT TERM...CONTINUING CIRCULATION ALONG QUASI-STATIONARY FRONTAL BOUNDARY STILL PRODUCING MODERATE RAINS ACROSS MAINLY FLAGLER AND S PUTNAM COUNTIES (ENHANCED BOTH BY LOW-LEVEL CONVERGENCE AND ISENTROPIC LIFT). GFS AND NGM FOCUS MOST PRECIP OFFSHORE THIS AFTN WHILE ETA WEAKENS THE PRECIP LATE IN THE DAY. HOWEVER...RUC KEEPS OFF AND ON CONVERGENCE ACROSS MAINLY COASTAL NE FL THRU THE DAY. EVEN IF GFS/NGM SCENARIO PANS OUT...SHOULD BE ENUF ONSHORE FLOW N OF BOUNDARY TO KEEP RAINS MOVING W. WITH THIS IN MIND...WILL GENERALLY KEEP POPS AS IS. HOWEVER...MAY SCALE BACK POPS OVER NW ZONES. WILL REDUCE TEMPS BY A FEW DEGS...ESP ACROSS INTERIOR N FL WHERE CLOUDS ARE STILL THICK. WILL HAVE TO CONTINUE TO MONITOR PRECIP ACROSS SE ZONES. WE'VE HAD 3-5 INCHES OF RAIN ACROSS S FLAGLER COUNTY IN THE PAST 2 DAYS OR SO. HAVE COVERED WITH AN FLS SO FAR...AND PRECIP HAS WANED A BIT OVER THE PAST 2 HOURS. && .MARINE...SCEC STILL LOOKING GOOD FOR AREA. IF SFC LOW DEVELOPS BY AFTN AS GFS SUGGESTS...WINDS COULD EASE BACK INTO SCA CRITERIA. HOWEVER...NOT BUYING THIS SOLUTION AND SHOULD KEEP 15 TO 20 KTS THRU THE REST OF THE DAY WITH HIGHER GUSTS. SEAS SHOULD STAY CAPPED AT 6 FT. && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. && $$ CARROLL/DEESE/KERNS fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 1057 AM CDT SUN AUG 8 2004 .DISCUSSION... LTL CHG TO GOING FCST WITH PRIMARY CONCERN TSTM TRENDS LATER THIS AFTN AND EVE. UPR LVL LOW PLOWING ALG ND/CANADA BORDER WITH TRAILING VORT LOBE INTO NE. ALTHOUGH WEAK KINEMATIC DOES DIP INTO NE...MUCH OF THE MID LVL QG FORCING LOOKS TO BE ROTATING FM THE DAKOTAS INTO MN. RECENT DVLPMT ACRS SWRN MN SEEMS ELEVATED IN WEAK ISENT LIFT/FRONTOGENETICAL FORCING ZN ALG H85/H7 TROF. 15Z SFC ANLYS SHOWING NON-DISTINCT FEATURES WITH SVRL WEAK PRES TROFS OR WND SHIFTS AHD OF MORE DEFINED THERMAL CHG ALG CDFNT FM ERN ND INTO WRN NE. THIS RESULTS IN WEAK SFC BASED CNVGNC WITH LEFT OVR DEBRIS CLOUDINESS SO WE HAVE AWHILE TO GO TO BCM SFC BASED. UPSTREAM SBCAPES NEGLIGABLE WITH PLENTY OF CIN. MUCAPE AXIS AND OF CNVGNC INTO WRN IA AS WELL. LATEST RUC/ETA RUNS STILL WANT TO OVERCOME THESE FACTORS HWVR AND DVLP TSTMS BY LATE AFTN. MID/HIGH CLDS APPR TO BE FADING SOMEWHAT SO EVEN THOUGH THERE IS A LACK OF SGFNT SHRT WV KICKER HAVE LEFT GOING LOW CATEGORY LIKELY POPS CONSIDERING AMT OF INSTABILITY AND POTENTIAL FOR RELATIVELY QUICK DCR OF CIN. IF DVLPMT DOES OCCUR...FEEL IT WILL BE A PULSEY HAIL EVENT. RUC MLCAPES REACH ARND 3000 J/KG DRNG PEAK HEATING BUT CNVGNC WEAK AND 0-6KM SHEAR LOW. AMT OF INSTABILITY ADEQUATE FOR A FEW SUPERCELLS BUT NOT LONG LIVED. COULD SEE SOME WND BUT A LESSER THREAT CONSIDERING FAIRLY MOIST SOUNDINGS AND WEAKER WNDS. HAVE ADDED LCLLY HEAVY RAIN WORDING TO HWO HWVR BASED ON INCRG LOW LVL MSTR AND XPCD SLOW MOVMT. DID NOT CHG AFTN HIGHS WITH INITIAL UPDATE WHICH BACKED OFF ON MRNG POPS...BUT WL LIKELY HAVE TO RAISE TEMP SHRTLY BASED ON CURRENT OBS WITH PROJECTED INCR IN SUNSHINE AND LOW LVL THERMAL AXIS UPSTREAM. NO CHGS TO LATER PDS WITH TSTMS XPCD TO LINGER INTO AT LEAST EVE HRS. .DMX WATCHES/WARNINGS/ADVISORIES...NONE && $$ SMALL ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1050 AM EDT SUN AUG 8 2004 .UPDATE... A PLEASANT DAY UNFOLDING ACROSS THE REGION WITH SURFACE HIGH PRESSURE FIRMLY IN CONTROL. CENTER OF THE 1022MB HIGH WAS ACROSS THE OHIO VALLEY WITH ITS RIDGE AXIS EXTENDING NORTH INTO THE STATE. MID LEVEL WARM ADVECTION CLOUD SHIELD EXTENDING FROM GRB INTO SOUTHWEST LOWER HAS THINNED SOMEWHAT OVER THE PAST HOUR AND WE WILL GO WITH MORE OPTIMISTIC SKY FORECAST TODAY BASED ON THE NEW 12Z RUN OF THE RUC AND ETA. AS THE AFTERNOON PROGRESSES...LAKE BREEZE DEVELOPMENT WILL BECOME MORE APPARENT AND COMBINING WITH SOME MID LEVEL MOISTURE UPSTREAM, WE SHOULD SEE MORE CU DEVELOP THIS AFTERNOON. ATMOSPHERE OVERALL DOES LOOK QUITE DRY WITH OUR 12Z SOUNDING REVEALING OUR PWATS AROUND 0.75"...THEREFORE NO PRECIP IN THE GRIDS. FORECAST HIGHS LOOKS GOOD WITH A NUDGE HIGHER THAN IN PREVIOUS GRIDS. BGM && .PREV DISCUSSION... ISSUED AT 225 AM EDT UNSEASONABLY COOL TEMPERATURES WILL CONTINUE TO BE THE MAIN WEATHER STORY OVER THE NEXT 7 DAYS. MONDAY CONTINUES TO LOOK LIKE THE WARMEST DAY...WITH NEAR NORMAL TEMPERATURES. TEMPERATURES WILL THEN PLUMMET BY MIDWEEK...DROPPING 10+ DEGREES BELOW NORMAL. SHEARED OUT SHORTWAVE MOVING THROUGH THE EXTREME SOUTHERN LOWER MICHIGAN/NORTHERN OHIO VALLEY THIS MORNING...PRODUCING NOTHING MORE THAN A MID DECK OF CLOUDS. MID LEVEL MOISTURE TO LINGER ACROSS MUCH OF WESTERN LOWER MICHIGAN THROUGH THE DAY. HOWEVER...IT LOOKS LIKE RIDGING AT THE SURFACE AND ALOFT BUILDING INTO LOWER MICHIGAN WILL PROVIDE A DRY DAY...PER 12Z 10KM TAQ RUQ AND 12Z MESOETA. TOUGH CALL OVER SOUTHEAST MICHIGAN TO GO WITH A MOSTLY CLOUDY OR PARTLY SUNNY FORECAST...AS THERE WILL BE A FAIRLY SHARP 1000 TO 500 MB RH GRADIENT. IT LOOKS TO BE A NO BRAINIER TO GO WITH PARTLY SUNNY (IF NOT MOSTLY SUNNY) FORECAST OVER THE THUMB REGION...AS 1000 TO 500 MB RH REMAINS BELOW 50 PERCENT. FAIRLY TRANSPARENT CLOUD CLOVER SHOULD ALLOW TEMPS TO COME VERY CLOSE OR ACTUALLY HIT 80 DEGREES ACROSS ALL OF SOUTHEAST MICHIGAN...BEFORE CU DEVELOPS DURING THE AFTERNOON AND CAUSES TEMPS TO LEVEL OFF. SURFACE RIDGE AXIS TO SHIFT EAST OF THE REGION TONIGHT...ALLOWING FOR A GRADUAL INCREASE IN MOISTURE. WILL GO WITH A DRY FORECAST AS THE MID LEVEL RIDGE REMAINS IN PLACE...AND MOST OF THE FORCING ASSOCIATED WITH THE WARM FRONT REMAINS NORTHWEST OF THE CWA. CURRENT WATER VAPOR IMAGERY INDICATING THE MAIN WEATHER PLAYER FOR MONDAY'S WEATHER. IMPRESSIVE UPPER LOW NEAR GLASGOW MONTANA MAKING STEADY PROGRESSIVE TO THE EAST. CLOSED CENTER EXPECTED TO REACH WESTERN LAKE SUPERIOR LATE MONDAY. MODELS INDICATING FROPA MONDAY NIGHT. BASED ON 00Z MESOETA...THE POTENTIAL FOR SEVERE WEATHER MONDAY EVENING CONTINUES. WILL CONTINUE WITH THE LIKELY POPS AS WELL...AS K INDICES CLIMB INTO THE UPPER 30S. MODELS DIVERGE A LITTLE BIT BY MIDWEEK...AS THE NEXT SHORTWAVE QUICKLY TAKES SHAPES AND PUSHES INTO THE WESTERN GREAT LAKES LATE TUESDAY OR WEDNESDAY MORNING...DEPENDING ON WHICH MODEL YOU BELIEVE. THE BIG QUESTION IS HOW FAST DOES THE FIRST WAVE DAMPEN OUT OR LIFT NORTHEAST ON TUESDAY...BEFORE THE NEXT UPPER LOW TAKES SHAPE. ALTHOUGH IT DOES LOOK LIKE SOUTHEAST MICHIGAN WILL BE UNDER THE INFLUENCE OF A DRY SLOT ON TUESDAY...PREFER TO MENTION A CHANCE OF CHANCE OF SHOWERS ACROSS THE NORTHERN THIRD OF THE CWA TUESDAY AFTERNOON...WITH THE GOOD CYCLONIC FLOW AND BEING CLOSER TO THE UPPER LEVEL COLD POOL. BOTH GFS AND ETA INDICATING 1000 TO 500 MB RH OF 70 PERCENT OR GREATER ACROSS THE TRI-CITIES AND THUMB REGION. BETTER CHANCE OF SHOWERS ON WEDNESDAY...AS ANOMALOUSLY DEEP UPPER LOW MOVES OVER NORTHERN LOWER MICHIGAN. COULD EVEN SEE SOME ENHANCEMENT OFF LAKE MICHIGAN...AS 84 HR ETA INDICATING 850 MB TEMPS OF 0 C! I DOUBT WE WOULD SEE 850 MB TEMPS THAT COLD...BUT EITHER WAY...IF SKIES REMAIN CLOUDY/MOSTLY CLOUDY...SURFACE TEMPS WILL HAVE A HARD TIME REACHING 70 DEGREES ON WEDNESDAY. NO CHANGES BEYOND WEDNESDAY...AS A LARGE SCALE TROUGH WILL BE IN PLACE OVER THE EASTERN HALF OF THE CONUS...KEEPING IT UNSEASONABLY COOL AND UNSETTLED. && .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 NATIONAL WEATHER SERVICE DULUTH MN 1000 AM CDT SUN AUG 8 2004 .DISCUSSION...FOCUS IS ON REGENERATION OF THUNDERSTORMS THIS AFTERNOON AND CONTINUATION THROUGH THE NIGHT. UPPER LOW IN THE IN THE DAKS HAS A NOTABLE DIFFLUENT AREA TO ITS EAST WHERE CLOUDS ARE LINGERING FROM LAST NIGHT'S PRECIP. UPR JET SWINGING AROUND THE BASE OF THE TROUGH HAS CLEARED A POTION IN THE ERN DAKS, BUT LATEST VSBL SATL IMAGERY SHOW N-S GROWTH OF CU THERE INDICATING IT IS STILL A POTENT REGION. VSBL IMAGERY ALSO SHOW CLDS THINNING OVR CNTRL MN TO W-C WI IN THE WAKE OF THE PRECIP. LAPS DATA OVR MN AND WI SHOW A SLOW DESTABLIZATION UNDERWAY. WE LEFT ISOLD SHWRS THIS MRNG OVR THE REGION DUE TO THE FACT THAT UPR DVGNC IS SWINGING THRU AND COULD POP A FEW INNOCENT SHWRS. WE LEFT ISOLD TSTMS FM BRD TO PKF DUE TO THE DESTABLIZATION. BUT WE TRENDED THE LIKELY DVLPMT OF AFTN CONVECTION. EARLY PANELS OF 12Z PROGS SHW THAT THE GFS IS DOING A GOOD JOB OF LOCATING THE SFC LOW AND UPR VORT MAX WHEN COMPARED TO THE RUC ANLYSIS. A STREAMLINE ANALYSIS ALG THE WM FNT NEAR BRD INDICATES A TWIST AS IF SOME LOCAL CONVERGENCE WERE SUBTLY TAKING PLACE. THE 18Z PANELS FROM THE 12Z RUN DO SHOW THIS TO BE A REGION OF HIGHER OMEGA WHICH SUPPORTS THE LAPS ANALYSIS. A DRY SLOT IS EVIDENT ON THE MODELS FM SW TO CNTRL MN BY 00Z WHICH WOULD MEAN THE BEST CONVECTION TO BE ON THE E SIDE IN THE MAX WAA AND THETA E ADVECTION. SO SOME ADJUSTMENT TO THE POPS AND PRECIP WORIDING WILL LIKELY RESULT THIS EVENING AS THE MAIN SVR WX THREAT MAY WELL BE OVR E-C MN AND NWRN WI. AREAS TO THE N MAY WELL BE IN THE CLDS LONG ENOUGH TODAY TO HOLD OFF THE SOLAR SUPPORT NEEDED. HWVR THE COLD POOL ALOFT WILL MEAN SUFFICIENT LAPSE RATES FOR SOME GOOD TSTMS UP THERE. .DLH...WATCHES/WARNINGS/ADVISORIES MN...NONE. WI...NONE. $$ CS mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 1005 AM CDT SUN AUG 8 2004 .DISCUSSION... HAVE UPDATED FORECAST FOR TODAY TO ACCOUNT FOR LONGER LASTING WARM AIR ADVECTION/ISENTROPIC LIFT GENERATED CONVECTION OVER EASTERN KS/NORTHWEST MO. SOUTHEAST NEBRASKA CLUSTER HAS FALLEN APART BUT NEW SCATTERED CONVECTION HAS FORMED DOWNSTREAM IN REGION THAT WAS RELATIVELY CLEAR EARLIER THIS MORNING. 12Z ETA/RUC SHOW A STRUNG OUT VORTICITY LOBE FROM CENTRAL KS THROUGH WEST CENTRAL MO WHICH IS PROVIDING ENOUGH LIFT WITH THE WARM AIR ADVECTION TO MAINTAIN STORMINESS INTO THE AFTERNOON. HAVE ALSO LOWERED HIGH TEMPERATURES FOR THIS AFTERNOON BY A CATEGORY IN THE WEST...MAY NOT HAVE BEEN AGGRESSIVE ENOUGH BUT WILL WAIT A FEW MORE HOURS. MJ && .PREV DISCUSSION... 335 AM... MAIN FORECAST CONCERNS ARE WITH CHANCES OF PRECIPITATION TODAY AND TONIGHT AND AGAIN TUESDAY NIGHT. UPPER PATTERN HAS FAIRLY COMPACT SHORT WAVE MOVING FROM DAKOTAS INTO MINNESOTA BY TONIGHT. UPPER FLOW BECOMES MORE DIFFLUENT ACROSS MISSOURI BY EVENING. SURFACE FRONT WILL STILL BE JUST NORTHWEST OF MISSOURI BY 06Z...WITH A WEAK SURFACE WAVE IN CENTRAL KANSAS. BETTER INSTABILITY SHOULD STAY FOCUSED CLOSER TO THIS SURFACE WAVE TO THE WEST OF FORECAST AREA THIS EVENING...WITH ONLY NORTHWEST CORNER SEEING CAPES IN THE 1500 J/KG RANGE. SHEAR ALSO RATHER WEAK THIS EVENING AS CONVERGENCE ALONG FRONT NOT GREAT...SO THINK SEVERE CHANCES WILL BE RATHER LIMITED. MODELS DO SHOW SOME POOLING OF MOISTURE AHEAD OF THE FRONT WITH SURFACE DEWPOINTS INTO NORTHWEST MISSOURI EXPECTED TO CLIMB INTO THE MIDDLE TO UPPER 60S. WILL GO WITH SOME LIKELY POPS IN NORTHWEST CORNER WHERE BEST INSTABILITY AND MOISTURE WILL BE OCCURRING THIS EVENING...BUT LEAVE CHANCE POPS ELSEWHERE AS THE ATMOSPHERE BECOMES MORE STABLE OVERNIGHT WITH THE SURFACE FRONT MOVING INTO CENTRAL MISSOURI. FOR THIS MORNING...WATCHING AC FORMING WITH WEAK ISENTROPIC LIFT INTO NORTHWEST MISSOURI. MAY BE ABLE TO SQUEEZE OUT A SHOWER...BUT HAVE NOT SEEN ANY DEVELOPMENT AS YET. WILL LEAVE POPS IN SLIGHT CATEGORY AT THIS POINT...BUT SOMETHING TO BE WATCHED. CURRENT STORMS IN NORTH CENTRAL NEBRASKA WILL ALSO HAVE TO BE WATCHED. CORFIDI VECTORS WOULD SUGGEST A SLOW SOUTHEAST MOVEMENT TO THE STORMS....WHICH WOULD TRACK MORE TOWARD NORTHEAST KANSAS RATHER MISSOURI. FOR TUESDAY...ANOTHER SHORT WAVE WITH ITS ORIGINS IN NORTHERN CANADA WILL BE DROPPING INTO NORTH CENTRAL PART OF COUNTRY AS WEST COAST RIDGE AMPLIFIES. MODELS A BIT DIFFERENT ON THEIR STRENGTH OF THIS WAVE...BUT ALL HAVE PRECIPITATION DEVELOPING IN AT LEAST PART OF THE FORECAST AREA BY TUESDAY EVENING AS THIS WAVE APPROACHES. WILL CONTINUE THE CHANCE POPS ALREADY IN FORECASTS. TEMPERATURE WISE...SHOULD SEE THE WARMEST DAY TODAY WITH HEATING OCCURRING AHEAD OF FRONT AND 850 TEMPERATURES CLIMBING INTO THE 16 TO 18 DEGREE RANGE. WILL SEE SLIGHTLY COOLER WEATHER ON MONDAY AFTER FRONT PASSES...BUT 850 TEMPERATURES STILL IN THE 14 TO 16 DEGREE RANGE. REAL COOL DOWN WILL HAVE TO WAIT UNTIL FRONT TUESDAY NIGHT DROPS THROUGH THE REGION. MODELS WOULD SUGGEST 850 TEMPS DROPPING AS LOW AS 6 TO 8 DEGREES BY THURSDAY MORNING. IS THIS REALLY AUGUST? PC && .PREV DISCUSSION... 342 PM SAT... MAIN FORECAST CONCERN THROUGH MONDAY CONTINUES TO BE WITH PRECIPITATION CHANCES. THE ETA AND GFS BOTH SHOW AN AREA OF ISENTROPIC UPGLIDE THAT SHIFTS TO EAST CENTRAL KANSAS LATE TONIGHT THROUGH EARLY TOMORROW MORNING. WITHIN THIS AREA...SOUNDINGS INDICATE A SHALLOW MOIST LAYER CENTERED AROUND 850MB ALONG WITH A POCKET OF COOLER 700MB TEMPERATURES. BOTH MODELS SHOW PRECIPITATION RIGHT ON OUR DOORSTEP BEFORE IT DISSIPATES. HAVE PLACED SLIGHT PRECIPITATION CHANCES OVER EXTREME WESTERN ZONES IN THE CASE THAT PRECIPITATION WILL DEVELOP THAT FAR EAST...THOUGH AMOUNTS SHOULD BE LIGHT. INCREASING CLOUD COVER OVERNIGHT TONIGHT SHOULD KEEP TEMPERATURES IN THE LOW TO MID 60S...A GOOD 5 DEGREES WARMER THAN LOWS LAST NIGHT. AFTER TONIGHT...DECENT RUN TO RUN AND INTER-MODEL CONSISTENCY LENDS ITSELF TO ONLY MINOR CHANGES TO THE FORECAST THROUGH MONDAY. STRONG MID/UPPER LEVEL SHORTWAVE TROUGH...CURRENTLY DEPICTED IN WATER VAPOR IMAGERY OVER NORTH CENTRAL MONTANA...AND CORRESPONDING SURFACE LOW WILL CONTINUE TO TRACK EAST ALONG THE NORTHERN CONUS/CANADIAN BORDER THROUGH THE WEEKEND. THE ATTENDANT COLD FRONT WILL ADVANCE EAST AND HOOK UP TO A LEE SIDE LOW EXPECTED TO DEVELOP OVER KANSAS TOMORROW. THE COLD FRONT IS TO REACH NORTHWEST MISSOURI TOMORROW NIGHT AND EXIT THE SOUTHERN FORECAST SECTIONS MONDAY MORNING...WITH PRECIPITATION TO DEVELOP IN THE PRIMED AIRMASS AHEAD OF THE FRONT. THE BEST CHANCE FOR ANY SEVERE STORMS WILL BE LATE TOMORROW AFTERNOON AND INTO THE EVENING AFTER DESTABILIZATION IN THE WARM SECTOR FROM DAYTIME HEATING. TEMPERATURES WILL SEE A TEMPORARY WARMUP TOMORROW WITHIN THE WARM SECTOR AHEAD OF THE FRONT...BEFORE COOLER AIR STARTS TO MOVE IN MONDAY. DID RAISE TEMPERATURES A TAD ON MONDAY PRIOR TO MORE SIGNIFICANT COLD PUSH MID-WEEK. MOIST SOUTHERLY FLOW RETURNS TO THE HIGH PLAINS QUICKLY BY TUESDAY. MEANWHILE A COLD FRONT IS FORECAST TO DROP SOUTH ACROSS THE PLAINS...AS A STRONG SHORTWAVE ROTATES THROUGH THE EAST CONUS TROUGH. MOISTURE AVAILABILITY ACROSS MISSOURI IS STILL SOMEWHAT IN QUESTION. HOWEVER ISENTROPIC LIFT IS PROGGED TO BE QUITE STRONG...SO HAVE LIMITED POPS TO THE LOW CHANCE CATEGORY WITH QPF AMOUNTS TAPERING OFF TOWARD THE NORTHEAST. EXPECT FRONT TO MOVE THROUGH QUICKLY TUESDAY NIGHT...HOWEVER HAVE MAINTAINED 20 TO 30 POPS INTO MAINLY WEDNESDAY MORNING. HAVE ALSO INTRODUCED A SLIGHT CHANCE INTO THE GRIDS TUESDAY AFTERNOON WITH STRENGTHENING WARM AIR ADVECTION/ISENTROPIC LIFT. THE STRONG SHORTWAVE IS PROGGED TO AMPLIFY THE EAST CONUS TROUGH...KEEPING TEMPS ON THE CHILLY SIDE THROUGH MUCH OF THE REST OF THE WEEK. HAVE THEREFORE LOWERED EXPECTED HIGHS BY ANOTHER 5 TO 8 DEGREES FOR MAINLY WEDNESDAY AND THURSDAY. ALSO ADJUST TEMPS DOWNWARD SLIGHTLY TUESDAY AND FRIDAY. WILL HAVE TO WATCH TEMPS ON TUESDAY IF IT LOOKS LIKE CLOUDS WILL BE MORE OF A CONCERN THAN CURRENTLY FORECAST. STOFLET/NRR && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ WFOEAX mo AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE STATE COLLEGE PA 1040 AM EDT SUN AUG 8 2004 .SHORT TERM (REST OF TODAY)... QUICK UPDATE TO REMOVE MENTION OF MORNING FOG. TEMPS LOOK FINE. EXPECT A MIX OF SUN AND CLOUDS TO DEVELOP ACROSS THE NORTH AND EAST WHERE LOW LEVEL MOISTURE REMAINS HIGHEST...OTHERWISE A MOSTLY SUNNY AFTERNOON IN STORE FOR CENTRAL PA. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 255 AM EDT SUN AUG 8 2004 AVIATION... WOULD EXPECT SOME FOG AT IPT...AND FOR A BRIEF TIME AT THE OTHER SITES THIS AM...BUT CLDS AND SOME WIND KEEPING FOG IN CHECK FOR NOW. OTHERWISE VFR CONDITIONS TODAY. MAINLY VFR CONDITIONS TONIGHT...BUT MAY BE SOME FOG BETWEEN 09Z AND 12Z...BUT EXPECT A SLIGHT BREEZE FROM THE W-NW...THUS NOTHING REAL DENSE. SHORT TERM (TODAY THROUGH TUESDAY)... WATER VAP IMAGERY SHOWING UPPER LO BEGINNING TO LIFT OUT OF NEW ENGLAND...WHILE WEAK S/WV DROPS SEWRD THRU OHIO VALLEY. LATEST RUC SUGGESTS STRATOCU OVER N MTNS LIFTS OUT BY 12Z...LEAVING ENTIRE FA MSUNNY BY LATER THIS MORNING. WESTERLY FLOW WILL ADVECT MILDER AIR FROM THE GRT LKS TODAY...WHERE HIGHS WERE CLOSE TO 80F YESTERDAY. OUR 850 TEMPS NR 11C SUGGEST SIMILAR READINGS IN THE VALLEYS...MINUS A FEW DEG IN MTNS. CLEAR SKIES/CALM WIND SHOULD ONCE AGAIN RESULT IN CHILLY READINGS TONIGHT. HOWEVER...WARMER MORE HUMID AIR RETURNS MONDAY AS SFC HIGH SLIPS OFF THE EAST COAST. POTENT S/WV...CURRENTLY OVER NORTHERN PLAINS...IS PROGGED TO PUSH EASTWARD OVER THE NEXT 72HRS...PUSHING A COLD FRONT THRU CENTRAL PA ON TUESDAY. INITIAL INDICATIONS FROM MODEL SOUNDINGS DO NOT SHOW A SIGNIFICANT SVR WX THREAT. ONLY MARGINAL INSTABILITY AND SHEAR. HOWEVER...A ROUND OF SHWRS/STORMS SEEMS A GOOD BET ALONG AND AHEAD OF FRONT. LONG TERM (TUESDAY NIGHT THROUGH SATURDAY)... 00Z MREF SUGGESTS THAT UPPER TROUGH SHARPENS OVER THE MIDWEST DURING MIDWEEK...CAUSING FRONTAL BOUNDARY TO HANG UP OVER THE APPALACHIANS. WILL KEEP SHWRS/STORMS IN FCST THRU THURSDAY...AFTER WHICH SOMEWHAT DRIER BUT STILL UNSETTLED WX FOR FRI/SAT AS UPPER TROUGH MOVES OVER THE AREA. WILL HAVE TO WATCH FOR FLOODING POTENTIAL AS SEVERAL ENSEMBLE MEMBERS ALREADY PRODUCING OVER ONE INCH OF RAIN WITH WAVE RIDING UP FRONT DURING WED/THURS. && .CTP WATCHES/WARNINGS/ADVISORIES... PA...NONE. && $$ SHORT TERM (UPDATE)...RXR pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 1027 AM EDT SUN AUG 8 2004 WILL OPT TO UPDATE THE GOING FCST TO MAKE SOME MINOR CHANGES TO MOSTLY THE FIRST PERIOD. .SYNOPSIS... HI PRESS TO STAY TO THE W-SW OF THE FA TODAY AND TONITE. SHORT WAVES TO RIDE DOWN ACRS THE FA...AND AROUND AN UPR TROF...TODAY AND EARLY TONITE. .SHORT TERM (THROUGH TONITE)... 06Z TAQ RUC SHOWS TEMPS TO GET UP INTO THE M60S-M70S TODAY WITH WESTERLY SFC WINDS AT 5-15 KTS. T1MAX TEMPS ARE IN THE L70S TODAY. FEW TWEAKS TO FIRST PERIOD TEMPS/WINDS BASED ON THIS DATA. LOW-LVL MSTR TO LINGER ACRS THE FA TODAY AND FOR MUCH OF TONITE. CAPES TO BE AOB 500 J/KG ACRS THE FA TODAY. PW VALUES LOOK TO BE 0.5-1" ACRS THE FA TODAY AND INTO TONITE. THIS CONFIRMED BY REGIONAL FSL GPS IPW SITES. RUC SHOWS SCT PCPN ACRS THE FA AGAIN TODAY WITH PTSUNNY SKIES OTRW. BUFCAN/88D MOSAIC SHOWS SOME WIDELY SCT PCPN ACRS SRN CANADA ATTM. FA IN SPC GEN TSTM OUTLOOK TODAY AND TONITE. WET-BULB ZERO HTS ACRS THE FA LOOK TO BE 6-8 KFT TODAY. WK H85 CAA TO TAKE PLACE ACRS THE FA EARLY TODAY...THEN WK WAA TO DEVELOP ACRS THE FA INTO TONITE. SOME LOW-LVL MSTR ADVECTION TO TAKE PLACE ACRS THE FA ON TODAY AND TONITE. LOW-LVL LAPSE RATES TO BE HI ACRS THE FA THIS AFTERNOON. SOME MID-LVL MSTR TO AFFECT THE FA TODAY. WILL HANG ONTO CHC POPS FOR ANY CONVECTION THAT MAKES IT ACRS THE FA TODAY. GOING MENTION OF SMALL HAIL AND THUNDER POSSIBLE WILL BE RETAINED AS WELL...BUT WOULDN/T BE SURPRISED TO SEE MUCH OF THIS ACTIVITY DISPLACED TO THE E-NE OF THE FA FROM WHERE IT WAS YESTERDAY. WILL ADDRESS ANY LINGERING PCPN PAST THE TODAY PERIOD ON THE AFTERNOON PACKAGE. CLDS STILL EXPECTED TO GRADUALLY DIMINISH ACRS THE FA AS THE NITE PROGRESSES TONITE. .HYDROLOGY... 24-HR QPE THRU 14Z TODAY ACRS THE FA LOOKED TO BE AOB 0.25"...WITH SOME ISOLATED AMTS AROUND AN INCH. MORE OF THE SAME EXPECTED OVER THE NEXT 24 HRS WITH SPOTTY CONVECTION POSSIBLE. WRK ZONES AVAILABLE. ALL FINAL PRODUCTS BY 11 AM. MURRAY .PREV DISCUSSION...FROM 312 AM EDT .SHORT TERM (TODAY THROUGH TUESDAY)... UPPER LOW THAT HAS BEEN OVER THE FORECAST AREA FOR THE LAST COUPLE OF DAYS WILL START TO MOVE OUT OF THE REGION TODAY. COLD POOL OF -20C AT 500 MB SHIFTS NORTHEAST...BUT WARMER SURFACE TEMPS WILL OFFSET IT SOMEWHAT TO DESTABILIZE SOUNDING. ONE MORE VORT MAX MOVING N TO S ACROSS THE REGION WILL HELP INITIATE CONVECTION AS WELL FOR SHOWERS/THUNDERSTORMS TODAY. WET BULB ZERO HEIGHT A LOW 7500 FT...AND BASED ON REPORTS OF SMALL HAIL YESTERDAY...EXPECT SOME SMALL HAIL TODAY AS WELL. FOR MONDAY...A BRIEF SHOT OF SUMMERTIME AS A SHORTWAVE RIDGE AT 500 MB MOVES ACROSS THE REGION. AT THE SURFACE...HIGH PRESSURE NOSES IN FROM THE SOUTH. PLENTY OF SUN...AND TEMPS A GOOD 10F WARMER THAN TODAY. TUESDAY...A WEAK COLD FRONT FORECAST TO MOVE THROUGH DURING THE DAY...WITH CHC SHOWERS/THUNDERSTORMS. A SHORTWAVE TROUGH AT 500 MB PUSHES THE UPPER RIDGE EAST...AND THE RIDGE BUILDS INTO A BLOCK THAT AFFECTS US IN THE EXTENDED PERIOD. UPPED POPS IN THE ST. LAWRENCE VALLEY TO LIKELY WEDNESDAY MORNING...IN AREA CLOSEST TO UPPER SUPPORT IS TIMED WITH FRONTAL PASSAGE. FOR TEMPS WENT CLOSE TO ETA/MET GUIDANCE NUMBERS...WHICH HAVE BEEN BEATING UP ON THE GFS/MAV GUIDANCE OVER THE PAST FEW DAYS. .LONG TERM (WEDNESDAY THROUGH SATURDAY)... NO CHANGES TO FORECAST HERE. LONG-WAVE 500 MB TROUGH DEEPENS OVER EASTERN US. BLOCKING RIDGE OFF ATLANTIC COAST ALLOWS LITTLE FORWARD PROGRESSION...AND THIS TIME THE TROF SETS UP TO THE WEST OF WHERE IT HAS BEEN OVER PAST FEW DAYS. TROF AXIS CENTERED MORE OVER UPPER MISSISSIPPI VALLEY/GREAT LAKES REGION...WITH SOUTHWESTERLY FLOW ALOFT ACROSS NE US. SHORTWAVE TROUGHS MOVING THRU BASE OF LONG-WAVE TROF WL MOVE ACROSS REGION...WITH PERIODIC CHCS FOR SHOWERS AND THUNDERSTORMS WEDS AND THURS. .AVIATION... VARIABLE AMOUNTS OF CLOUD COVER EARLY THIS MORNING WITH MOSTLY CLEAR SKIES ACROSS NORTHERN NEW YORK AND PARTLY TO MOSTLY CLOUDY SKIES OVER VERMONT. SOME AREAS OF FOG EARLY THIS MORNING AT KSLK AND KMVL. EXPECT THESE AREAS OF FOG TO BURN OFF BY 12Z. COLD POOL OF AIR ALOFT OVER THE REGION TODAY WILL LEAD TO INCREASING AMOUNTS OF CLOUD COVER TO DEVELOP OVER THE REGION DURING DAYTIME HEATING WITH SCATTERED SHOWERS DEVELOPING AS WELL. EXPECTING VFR CONDITIONS DURING THE DAY WITH SOME AREAS OF MVFR IN SHOWERS. HIGHER TERRAIN WILL BE OBSCURED AT TIMES IN AREAS OF SHOWERS. MODEL SOUNDINGS SUGGEST SOME ISOLATED THUNDERSTORMS AND SMALL HAIL ARE POSSIBLE THIS AFTERNOON. EXPECTING VFR CONDITIONS TONIGHT THROUGH 06Z AS ANY SCATTERED SHOWERS EARLIER IN THE AFTERNOON WILL HAVE DIMINISHED DUE TO THE LOSS OF DAYTIME HEATING. SHORT TERM/LONG TERM...HANSON AVIATION...WGH .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ vt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 200 PM MDT SUN AUG 8 2004 .DISCUSSION...FORECAST CHALLENGE IS WX/POP FORECASTS THE NEXT FEW DAYS AND IMPACT OF MUCH COOLER AIRMASS ON TEMPERATURES. AT 20Z SATELLITE DATA SHOWING 2 BOUNDARIES ACROSS THE AREA. FIRST WAS FROM MCCOOK TO NEAR GOODLAND WHILE A SECOND ONE WAS NEAR THE HILL CITY AREA. 18Z RUC HAS A GOOD HANDLE ON CURRENT CONDITIONS AND WILL WEIGHT THE SHORT TERM FORECAST ON IT FAIRLY HEAVILY. TONIGHT/MONDAY...THROUGH THE FIRST 3 HOURS WE WILL FOCUS ON THE FRONTAL BOUNDARY OVER OUR SOUTHEAST ZONES AND NORTHERN. RUC HAS BEEN DOING WELL FOR THE DAY SO CANT IGNORE ITS QPF FORECAST ALONG THE SECOND FRONTAL BOUNDARY. OTHERWISE...EXPECT BOTH BOUNDARIES TO LOSE THEIR CONVECTION BY MIDNIGHT AS UPPER FORCING AND DAYTIME HEATING DISSIPATE. WILL WAIT TIL LAST MINUTE TO TWEAK THE SHORT TERM PERIOD. OTHERWISE...STRONG UPPER LOW MOVES SOUTHEAST ACROSS THE NORTHERN PLAINS BRINGING HIGH PRESSURE...NORTHEAST TO EAST WINDS...AND COOLER AIR TO THE AREA. ON MONDAY SOUTHEAST WINDS RETURN SOME MOISTURE TO THE SOUTHWEST PORTION OF THE AREA WITH MODEL QPF/HPC ALSO SHOWING A SMALL CHANCE ELSEWHERE...ALTHOUGH I AM NOT SURE WHY. WILL HAVE HIGHEST POPS SOUTHWEST WITH SLIGHT CHANCE ELSEWHERE. TEMPERATURES IN THE MID 70S TO NEAR 80 BASED ON 850 COOLING FROM SUNDAYS READINGS. MONDAY NIGHT/TUESDAY...ANOTHER STRONG UPPER LOW MOVES SOUTH OUT OF CANADA...MOVING IN A MORE SOUTHERLY DIRECTION TOWARD THE NORTHERN PLAINS. THIS WILL BRING YET ANOTHER SHOT OF COOLER AIR TO THE AREA... ODD FOR THIS TIME OF YEAR. GFS AS WELL AS ITS PREVIOUS RUN ALONG WITH PREVIOUS RUN OF ETA AND UKMET/ECMWF BRING SINGLE DIGIT 850 TEMPERATURES INTO THE AREA BY DAYS END. HIGHS ACCORDINGLY WILL BE EARLY IN THE DAY WITH UPPER 60S NORTHEAST TO LOWER 80S FAR SOUTH. OF MORE CONCERN IS PRECIP CHANCES. EAST WINDS CONTINUE DURING THE DAY WITH AN AXIS OF INSTABILITY OVER MUCH OF THE AREA. DONT HAVE A GOOD FEEL FOR THE POP FORECAST BUT MAV/MET POPS IN A FAVORABLE AREA NOT TO CUT THEM THIS YEAR AND SURROUNDING OFFICES SEEM TO HAVE A BETTER FEEL SO I WILL UP MY POPS TO MATCH THEIRS. TUESDAY NIGHT/WEDNESDAY...AS A LARGE UPPER TROUGH CARVES ITSELF OUT OVER THE EASTERN HALF OF THE COUNTRY THE WESTERN HALF WILL BE UNDER UPPER LEVEL RIDGING. THE CENTRAL PLAINS WILL BE IN THE TRANSITION AREA WITH MUCH LOWER THEN NORMAL TEMPERATURES AS HIGH PRESSURE IS THE DOMINANT WEATHER FACTOR. COULD FLIRT WITH SOME RECORD LOWS (MID- UPPER 40S) GIVEN THIS UNUSUAL AIRMASS. PREFER THE GFS/UKMET/ECMWF AND 06Z RUN OF THE ETA WHICH DRIVE NORTHEAST WINDS FURTHER SOUTH AND HENCE THE COOLER AIR THAN THE ETA. ENSEMBLE GFS ALSO HAS A SIMILAR SCENARIO. HIGH TEMPERATURES RIGHT AROUND 70 PER ETA/GFS/ENSEMBLE AND MEX GUIDANCE NUMBERS. THURSDAY-SUNDAY...UPPER LEVEL PATTERN DOESNT CHANGE A WHOLE LOT. UPPER TROUGH OVER THE EASTERN HALF OF THE COUNTRY SLOWLY LIFTS NORTHEAST ALLOWING SLOWLY BUILDING HEIGHTS OVER THE WEST. SOUTHERLY WINDS AND LEE TROUGH SUPPORT LONG RANGE GFS AND ITS PREVIOUS RUN OF SLOWLY MODERATING TEMPERATURES THROUGH THE PERIOD. AS FAR AS PRECIP CHANCES...BEST SCENARIO WOULD BE OVER FAR EASTERN COLORADO WHERE LOW LEVEL SOUTHERLY WINDS WORK WITH NORTHWEST WINDS ALOFT TO PRODUCE ADEQUATE SHEAR FOR FRONT RANGE AFTERNOON CONVECTION TO MOVE EAST/SOUTHEAST DURING THE LATE AFTERNOON/EARLY EVENING HOURS ACROSS MUCH OF THE WESTERN FORECAST AREA. GENERAL FORECAST IS DRY GIVEN LACK OF DETAILS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ DDT ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 337 PM EDT SUN AUG 8 2004 .DISCUSSION... MAIN CONCERNS WITH THIS FORECASTS ARE SHOWERS AND THUNDERSTORMS POTENTIAL TONIGHT THROUGH MON. WATER VAPOR IMAGERY AND RUC/ETA SHOWING A CLOSED LOW SPINNING OVER EASTERN NORTH DAKOTA AND A RIDGE OVER THE UPPER GREAT LAKES. A WEAK SHORTWAVE IS BEING EJECTED FROM THE CLOSED LOW INTO THE RIDGE. SURFACE ANALYSIS INDICATE A LOW OVER SOUTHERN MANITOBA WITH A COLD FRONT EXTENDING SOUTH THROUGH WESTERN MINNESOTA INTO EASTERN NEBRASKA. A BROAD RIDGE BLANKETS MUCH OF SOUTHEAST CONUS THIS AFTERNOON. ANTI-CYCLONIC FLOW BEHIND THE RIDGE IS DRAWING WARM MOIST AIR AHEAD OF THE FRONT INTO THE UPPER GREAT LAKES. COOL CANADIAN AIR IS FORCING AN ARCTIC COLD FRONT...THAT STRETCHES FROM SOUTHERN SASKATCHEWAN TO JAMES BAY...TOWARDS THE FORECAST AREA. SHOWERS AND THUNDERSTORMS ARE FIRING AHEAD OF THE FRONT AND NEAR THE CONFLUENCE OF THE THE TWO FRONTS OVER SOUTHERN MANITOBA. THE CLOSE LOW OVER NORTH DAKOTA WILL SLIDE INTO NORTHERN MINNESOTA TONIGHT. Q-VECTOR ANALYSIS SUGGEST THAT THE SHORTWAVE ENERGY AHEAD OF THE LOW WILL SHIFT OVER THE FORECAST AREA. THE SURFACE LOW WILL MOVE TO JUST NORTH OF THE MINNESOTA ARROWHEAD DIRECTING THE COLD FRONT INTO NORTHERN WISCONSIN AND WESTERN LAKE SUPERIOR. ISENTROPIC ASCENT AHEAD OF THE COLD FRONT WILL TRIGGER SHOWERS AND THUNDERSTORMS OVER THE AREA TONGIHT. A BROAD CANADIAN HIGH WILL START TO SHIFT SOUTH ALONG THE CONTINENTAL DIVIDE AND SPREAD INTO THE NORTHERN HIGH PLAINS. A 75 KNOT UPPER LEVEL CYCLONIC JET WILL SLIDE OUT OF THE DAKOTA INTO WISCONSIN...PLACING THE U.P. UNDER THE LEFT EXIT REGION OF THE JET BY EARLY MORNING AND STRONG DIVERGENCE. THIS ENHANCE THUNDERSTORM DEVELOP. THE MID LEVEL CLOSED LOW WILL WORK INTO WESTERN LAKE SUPERIOR ON MONDAY AS WILL THE SURFACE LOW. THE COLD FRONT WILL REACH TO EASTERN UPPER MICHIGAN DURING THE DAY. MOISTURE AHEAD OF THE FRONT AND WRAPPING AROUND THE LOW WILL FEED THE SHOWERS AND THUNDERSTORMS OVER THE AREA. Q-VECTOR CONVERGENCE AHEAD OF THE CLOSED LOW WILL NAVIGATE ACROSS THE AREA ON MONDAY AND REACH EAST CENTRAL ONTARIO LATE IN DAY. ETA/GFS SHOW THAT COLD ADVECTION ALOFT WILL SET UP CAPE VALUES OF 1400J/KG OVER THE FORECAST AREA ON MONDAY...ESCPECIALLY OVER THE SOUTH CENTRAL. THE GREATEST INSTABILITY WILL STILL BE TO THE SOUTH OF THE FORECAST AREA. THE THUNDERSTORM WILL CONTINUE AND THE CHANCE OF THUNDERSTORMS WILL GRADUALLY DIMISHING IN THE WEST DURING THE AFTERNOON. THE CLOSED LOW WILL MOVE TO EASTERN U.P. MONDAY NIGHT. A SURFACE LOW WILL MOVE INTO SOUTHEAST ONTARIO MONDAY NIGHT. ANOTHER CLOSED LOW WILL DEVELOP OVER SOUTHERN MANITOBA. WEAK SHORTWAVE WILL WRAP THROUGH THE BASE OF THIS LOW AND THROUGH NORTHERN PLAINS. THE COLD FRONT WILL MOVE INTO LOWER MICHIGAN. MOISTURE WILL CONTINUE OVER THE AREA. CAPE VALUES WILL DIMINISH OVER NIGHT. STILL EXPECT ENOUGH INSTABILITY ALONG WITH THE AVAILABLE MOISTURE TO KEEP A CHANCE OF SHOWERS IN FOR MONDAY NIGHT. THE CLOSED LOW OVER THE EASTERN U.P. WILL WEAKEN AS IT MOVES INTO EASTERN ONTARIO ON TUESDAY. THE LOW OVER MANITOBA WILL SWING INTO CENTRAL MINNESOTA. A SHORTWAVE ROTATING AROUND THIS LOW WILL SLIDE TO THE SOUTH OF THE FORECAST AREA. HOWEVER...ANOTHER WEAK SHORTWAVE ROTATING AROUND THIS LOW WILL SHOOT ACROSS THE U.P. DURING THE DAY. ETA/GFS KEEPS THE MEAN SURFACE SURFACE-500MB RH AROUND 85 PERCENT. ISENTROPIC ASCENT ACCOMPANYING A WEAK TROUGH COULD TRIGGER A FEW SHOWERS. THE LONGWAVE TROUGH REMAINS OVER THE UPPER GREAT LAKES TUESDAY NIGHT. THE MID LEVEL LOW WILL ROTATE THROUGH THE BASE OF THE TROUGH AND MOVE FROM MINNESOTA INTO WISCONSIN. THE SURFACE LOW WILL BLANKET EAST CENTRAL ONTARIO. THE SURFACE TROUGH WILL SHIFT A LITTLE SOUTHEAST TO LOWER MICHIGAN. A SURFACE RIDGE WILL PUSH INTO THE NORTHERN HIGH PLAINS. SHORTWAVE ENERGY WILL SHIFT ACROSS THE FORECAST AREA. GFS SUGGESTS LOW LEVEL MOISTURE WILL REMAIN OVER THE AREA AND PRODUCE SOME SHOWERS. GFS CONTINUES TO BE STRONGEST WITH THE SHORTWAVE MOVING THROUGH THE UPPER GREAT LAKES ON WEDNESDAY. CANADIAN GLOBAL IS THE WEAKEST AND ECMWF IS A COMPROMISE BETWEEN THE OTHER MODELS. MODELS AGREE ON THE TIMING...BUT THE STRENGTH OF THE SYSTEM VARIES. THE MID LEVEL LOW WILL MOVE INTO LAKE HURON ON WEDNESDAY. THE SURFACE LOW WILL SHIFT INTO CENTRAL QUEBEC. MEANWHILE...A WEAK COLD FRONT IS PROGGED TO DEVELOP AND MOVE INTO LAKE SUPERIOR. THERE SHOULD BE ENOUGH ISENTROPIC LIFT AND SHORTWAVE ENERGY TO GENERATE A SHOWERS. ANOTHER SHORTWAVE ROTATING THROUGH THE BASE OF THE LONGWAVE WILL MOVE THROUGH THE FORECAST AREA WEDNESDAY NIGHT. THE SURFACE LOW AND ACCOMPANYING COLD FRONT WILL MOVE EAST INTO THE ATLANTIC COASTAL STATES WHILE THE SURFACE RIDGE SPREADS INTO THE CENTRAL PLAINS. GFS/ECMWF SHOW DRIER AIR WILL ADVECT INTO THE AREA OVERNIGHT. THIS SHOULD REDUCE THE CHANCES OF RAIN OVERNIGHT. GFS/ECMWF AGREE CLOSELY ON PLACEMENT OF A CLOSED LOW...EMBEDDED IN THE LONGWAVE TROUGH...OVER THE SOUTHERN U.P. ON THURSDAY. SHORTWAVE ENERGY SWINGING THROUGH THE BASE OF THIS TROUGH ARE PROGGED TO SLIDE JUST TO THE SOUTHWEST OF THE FORECAST AREA AND DRY AIR WILL REMAIN ENTRENCHED OVER THE AREA. SURFACE FEATURES INDICATED THE NORTHERN PLAINS RIDGE WILL PUSH INTO THE UPPER MISSISSIPPI RIVER VALLEY. THE CLOSED LOW EMBEDDED IN THE LONGWAVE TROUGH WILL MOVE OVER LOWER MICHIGAN PLACING THE U.P. ON THE BACKSIDE OF THE TROUGH THURSDAY NIGHT AND FRIDAY. SHORTWAVE ENERGY WILL CONTINUE TO SHIFT TO THE WEST OF THE FORECAST AREA. THE APPROACHING SURFACE RIDGE WILL START TO PUSH INTO THE UPPER GREAT LAKES DRAWING COOLER DRIER AIR INTO REGION. THE LONGWAVE TROUGH WILL WEAKEN FRIDAY NIGHT THROUGH SUNDAY AS IT SHIFTS INTO EASTERN CANADA AND ALONG THE EAST COAST. A WEAK SHORTWAVE RACING THROUGH THE BASE OF THE TROUGH WILL SHIFT ACROSS THE FORECAST AREA SATURDAY NIGHT AND SUNDAY. THE SURFACE RIDGE WILL MOVE OVER THE UPPER GREAT LAKES AND INTO THE OHIO RIVER VALLEY ON SATURDAY AND SUNDAY. A WEAK SURFACE TROUGH WILL MOVE INTO THE FORECAST AREA ON SUNDAY. GFS SHOW MEAN SURFACE-500MB RH AROUND 70 PERCENT OVER THE U.P. ON SUNDAY. THUS CONDITIONS ARE SUCH THAT THERE MAY BE A CHANCE OF SHOWERS ON SUNDAY. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 355 PM CDT SUN AUG 8 2004 .DISCUSSION... SLOW MOVING COLD FRONT WHICH CURRENTLY STRETCHES FROM NORTHWEST CORNER KS THROUGH NORTH CENTRAL IA WILL BE THE PRIMARY PRECIPITATION PLAYER THROUGH TUESDAY NIGHT. LACKING MUCH FLOW THROUGH 500 MB THERE WILL BE MINIMAL PUSH ON FRONT ACROSS CWA EXCEPT FOR OUTFLOW BOUNDARIES. 18Z META CONTINUED PREVIOUS MODEL TRENDS OF TAKING ITS TIME IN MOVING FRONT THROUGH. 12Z GFS IS NOT QUITE AS SLOW AND FORCES COLD FRONT THROUGH CWA BY EARLY MONDAY AFTERNOON. THINK IT BEST TO HOLD ONTO POPS FOR SOUTHERN HALF OF CWA INTO EARLY MONDAY EVENING. CURRENT SCENARIO IS FOR CONVECTION TO CONTINUE FORMING ALONG FRONT FROM SOUTH CENTRAL NEB BUT HAVE DIFFICULTY DEVELOPING INTO SOUTHWEST IA/NORTHWEST CORNER MO DUE TO STABILIZING INFLUENCE OF EARLIER ACTIVITY. EVENTUALLY STORMS WILL MOVE INTO NORTHWEST CORNER SO HAVE LIKELY POPS THERE. CONVECTION WILL BE MAINLY DIURNALLY DRIVEN UNLESS A GOOD COLD POOL CAN BE GENERATED TO FORCE STORMS SOUTH AND SOUTHEAST TOWARDS BETTER INSTABILITY. SO WILL TAPER POPS FROM NORTHWEST TO SOUTHEAST WITH IDEA CONVECTION MAY NEVER REACH SOUTHEAST PORTION OF CWA. BUMPED TEMPERATURES/DEWPOINTS UP TONIGHT ACROSS MAINLY NORTHWEST MO AND ACROSS MOST OF CWA ON MONDAY. MINIMAL COOLING WILL FOLLOW COLD FRONT PASSAGE FOR TUESDAY. INCREASING WARM AIR ADVECTION ABOVE 850MB TUESDAY NIGHT FORECAST BY GFS/ETA AND CANADIAN MODELS WARRANTS CONTINUED CHANCE POPS IN THE 40 PERCENT CATEGORY. GFS/CANADIAN QPF IS RATHER HIGH AND CANT RULE IT OUT SINCE APPROACHING COLD FRONT WILL LIKELY FORM A GOOD ELEVATED CONVERGENCE ZONE AS STRONG SHORTWAVE PLUNGES SOUTHEAST OUT OF SOUTH CENTRAL CANADA. MJ THE MEDIUM RANGE MODELS CONTINUE TO COME IN WITH EVEN COLDER SOLUTIONS FOR MID WEEK...SHOWING ANOMALOUSLY LOW HEIGHTS WITH THE UPPER TROUGH EXTENDING SOUTH OUT OF CENTRAL CANADA. FOLLOWING THE EXIT OF THE SECONDARY COLD FRONT...THESE LOWERING HEIGHTS WILL ALLOW FOR THE INTRUSION OF EXTREMELY UNSEASONABLE COOL AIR ACROSS THE MIDWEST BEGINNING WEDNESDAY. A SECONDARY DIGGING OF THE UPPER TROUGH FROM ADDITIONAL SHORTWAVE ENERGY IS ADVERTISED WEDNESDAY NIGHT INTO THURSDAY. THIS WILL REINFORCE THE COOL AIRMASS THROUGH THE MISSISSIPPI VALLEY AND INCREASE CLOUD COVER ON THURSDAY. HIGH TEMPERATURES FOR WEDNESDAY THROUGH FRIDAY SHOULD NOT BE ABLE TO WARM OUT OF THE 70S...WITH LOWS FALLING INTO THE 50S. A SLIGHT WARMING TREND WILL ENSUE NEXT WEEKEND AS THE DEEP TROUGH PULLS AWAY TOWARD THE EASTERN COAST. STOFLET && .PREV DISCUSSION... 1005 AM... HAVE UPDATED FORECAST FOR TODAY TO ACCOUNT FOR LONGER LASTING WARM AIR ADVECTION/ISENTROPIC LIFT GENERATED CONVECTION OVER EASTERN KS/NORTHWEST MO. SOUTHEAST NEBRASKA CLUSTER HAS FALLEN APART BUT NEW SCATTERED CONVECTION HAS FORMED DOWNSTREAM IN REGION THAT WAS RELATIVELY CLEAR EARLIER THIS MORNING. 12Z ETA/RUC SHOW A STRUNG OUT VORTICITY LOBE FROM CENTRAL KS THROUGH WEST CENTRAL MO WHICH IS PROVIDING ENOUGH LIFT WITH THE WARM AIR ADVECTION TO MAINTAIN STORMINESS INTO THE AFTERNOON. HAVE ALSO LOWERED HIGH TEMPERATURES FOR THIS AFTERNOON BY A CATEGORY IN THE WEST...MAY NOT HAVE BEEN AGGRESSIVE ENOUGH BUT WILL WAIT A FEW MORE HOURS. MJ && .PREV DISCUSSION... 335 AM... MAIN FORECAST CONCERNS ARE WITH CHANCES OF PRECIPITATION TODAY AND TONIGHT AND AGAIN TUESDAY NIGHT. UPPER PATTERN HAS FAIRLY COMPACT SHORT WAVE MOVING FROM DAKOTAS INTO MINNESOTA BY TONIGHT. UPPER FLOW BECOMES MORE DIFFLUENT ACROSS MISSOURI BY EVENING. SURFACE FRONT WILL STILL BE JUST NORTHWEST OF MISSOURI BY 06Z...WITH A WEAK SURFACE WAVE IN CENTRAL KANSAS. BETTER INSTABILITY SHOULD STAY FOCUSED CLOSER TO THIS SURFACE WAVE TO THE WEST OF FORECAST AREA THIS EVENING...WITH ONLY NORTHWEST CORNER SEEING CAPES IN THE 1500 J/KG RANGE. SHEAR ALSO RATHER WEAK THIS EVENING AS CONVERGENCE ALONG FRONT NOT GREAT...SO THINK SEVERE CHANCES WILL BE RATHER LIMITED. MODELS DO SHOW SOME POOLING OF MOISTURE AHEAD OF THE FRONT WITH SURFACE DEWPOINTS INTO NORTHWEST MISSOURI EXPECTED TO CLIMB INTO THE MIDDLE TO UPPER 60S. WILL GO WITH SOME LIKELY POPS IN NORTHWEST CORNER WHERE BEST INSTABILITY AND MOISTURE WILL BE OCCURRING THIS EVENING...BUT LEAVE CHANCE POPS ELSEWHERE AS THE ATMOSPHERE BECOMES MORE STABLE OVERNIGHT WITH THE SURFACE FRONT MOVING INTO CENTRAL MISSOURI. FOR THIS MORNING...WATCHING AC FORMING WITH WEAK ISENTROPIC LIFT INTO NORTHWEST MISSOURI. MAY BE ABLE TO SQUEEZE OUT A SHOWER...BUT HAVE NOT SEEN ANY DEVELOPMENT AS YET. WILL LEAVE POPS IN SLIGHT CATEGORY AT THIS POINT...BUT SOMETHING TO BE WATCHED. CURRENT STORMS IN NORTH CENTRAL NEBRASKA WILL ALSO HAVE TO BE WATCHED. CORFIDI VECTORS WOULD SUGGEST A SLOW SOUTHEAST MOVEMENT TO THE STORMS....WHICH WOULD TRACK MORE TOWARD NORTHEAST KANSAS RATHER MISSOURI. FOR TUESDAY...ANOTHER SHORT WAVE WITH ITS ORIGINS IN NORTHERN CANADA WILL BE DROPPING INTO NORTH CENTRAL PART OF COUNTRY AS WEST COAST RIDGE AMPLIFIES. MODELS A BIT DIFFERENT ON THEIR STRENGTH OF THIS WAVE...BUT ALL HAVE PRECIPITATION DEVELOPING IN AT LEAST PART OF THE FORECAST AREA BY TUESDAY EVENING AS THIS WAVE APPROACHES. WILL CONTINUE THE CHANCE POPS ALREADY IN FORECASTS. TEMPERATURE WISE...SHOULD SEE THE WARMEST DAY TODAY WITH HEATING OCCURRING AHEAD OF FRONT AND 850 TEMPERATURES CLIMBING INTO THE 16 TO 18 DEGREE RANGE. WILL SEE SLIGHTLY COOLER WEATHER ON MONDAY AFTER FRONT PASSES...BUT 850 TEMPERATURES STILL IN THE 14 TO 16 DEGREE RANGE. REAL COOL DOWN WILL HAVE TO WAIT UNTIL FRONT TUESDAY NIGHT DROPS THROUGH THE REGION. MODELS WOULD SUGGEST 850 TEMPS DROPPING AS LOW AS 6 TO 8 DEGREES BY THURSDAY MORNING. IS THIS REALLY AUGUST? PC && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ WFOEAX mo AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PITTSBURGH PA 525 PM EDT SUN AUG 8 2004 .SHORT TERM (REST OF TONIGHT)... HAVE INCLUDED MENTION OF ISOLATED SHOWERS EARLY THIS EVENING PER LATEST RADAR AND SATELLITE DATA SHOWING ISOLATED SHOWERS AND MODERATE CUMULUS ACROSS THE UPPER OHIO VALLEY. PER LATEST RUC MODEL EXPECT CURRENT INSTABILITY TO DECREASE AFTER SUNSET. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 212 PM EDT SUN AUG 8 2004 AVIATION... MID AND HI CLOUDS THAT MOVED ACROSS EAST CENTRAL OH WILL EXIT ACROSS NRN WV THIS AFTN. AREA TO NORTH THAT WAS GENERALLY CLEAR FILLING IN WITH SCT-BKN CU THIS AFTN. WILL GENERALLY GO WITH SCT-BKN050 THIS AFTN WITH CU DISSIPATING AROUND SUNSET. BUFKIT AND MOS BOTH SUGGEST SOME FOG POSSIBLE TUE MORNING. WILL GO TEMPO 4-5SM BR AROUND SUNRISE WITH MID LEVEL CLDS. CU REDEVELOPS LATE MON MORNING. SHORT TERM (THROUGH TUE NIGHT)... LOOKING AT THE BROAD CIRCULATION, GFS AND ETA MODELS ARE SIMILAR. BUT THE LTL H5 LOW OR S/W OVER N DAK 18Z TDA WEAKENS AND OPENS INTO A WEAK TROF. BY 06Z TUE, ETA KEEPS A CLOSED CENTER, WHICH DISAPPEARS 6 HRS LATER. STRENGTHS AND TIMING ARE SIMILAR IN BOTH MODELS. NOW ITS JUST A QUESTION OF CHC OR LIKELY POPS AHEAD OF FRONTS OVER THE NEXT WEEK. SFC LOWS ARE WITHIN 2 MB OF EA OTHER. BOTH MODELS HAVE ONE SFC FRONT PASSING PIT 18Z TUE W/ SECONDARY TROF 15-18Z WED. LONG TERM (WED THROUGH SUN)... GFS IS STRONGER WITH A SFC LO, DEVELOPING IT IN INDIANA EARLY WED. ETA DOES NOT DO THIS. AND ON WED, GFS HAS SOME KIND OF FEEDBACK PROBLEM WITH HUGE AMOUNT OF PCPN IN INDI-OHIO, NR WHERE THE ALLEDGED SFC LO DEVELOPS. ETA HAS NO SUCH ANIMAL. ETA HAS COLD FRONT MOVING EAST OF THE FORECAST AREA TUE EVENING, AND SHOWERS WOULD DIMINISH. BUT GFS HAS SFC LO AND POSSIBLE CONVECTIVE FEEDBACK MOVING FROM INDIANA TO PA BY WED NIGHT. CONSISTENT WITH NEIGHBORS, I KEPT POPS 30-40% WED NIGHT AND LONG RANGE GFS HAS H5 TROF W OF CWA THU MRNG. POPS GO TO 50-60% THU AND FRI, THEN DECREASE AS TROF FINALLY GETS E OF ME 00Z SAT 14TH. THEN DRY WEATHER ARRIVES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ SHORT TERM...11 pa