INTERIOR CENTRAL CALIFORNIA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HANFORD CA 330 AM PDT MON JUN 17 2002 SATELLITE AND RUC ANALYSIS CONTINUE TO SHOW THE DISTRICT UNDER THE SOUTHWEST FLOW OF THE WESTERN RIDGE. THE UPPER LOW...NOW CENTERED NEAR 38N/142W...CONTINUES TO SPIN OFFSHORE AND IS TRACKING TOWARDS SOUTHWEST BRITISH COLUMBIA. TIMING OF THIS UPPER LOW TO PUSH THROUGH THE PACIFIC NORTHWEST IS STILL SCHEDULED FOR TUESDAY. AS THE LOW CONTINUES TO APPROACH THE PACIFIC NORTHWEST...WILL START TO SEE THE RIDGE FLATTEN TODAY AS THE FLOW BECOMES MORE ZONAL. HEIGHTS AND 850MB TEMP/S SHOW MINIMAL CHANGE TODAY /FROM SUNDAY/ SO WILL STAY WITH PERSISTENCE AND KEEP TEMP/S ABOUT THE SAME TO THOSE OF YESTERDAY. SURFACE PRESSURE GRADIENTS ARE CURRENTLY RUNNING ABOVE 10MB THIS MORNING FROM SFO-LAS. THIS IS TRANSLATING INTO CONTINUED LOCALLY BREEZY WINDS ACROSS THE DISTRICT OVERNIGHT. SHORT RANGE MODELS SHOW NO REAL DIFFERENCE IN THE GRADIENTS THIS AFTERNOON...SO WILL MAINTAIN CURRENT SPEEDS THROUGH OUT THE DAY. IN THE SHORT RANGE...MODELS SHOW THE UPPER LOW SWINGING THROUGH THE PACIFIC NORTHWEST INTO THE UPPER MID-WEST BY LATER WEDNESDAY. WILL SEE BEST HEIGHT FALLS ON TUESDAY FOR THE START OF A COOLING TREND. IN ADDITION...MODELS SHOW THE SOUTHERN EXTENT OF MID LEVEL MOISTURE PUSHING THROUGH THE NORTHERN PARTS OF THE DISTRICT. THE MAIN AFFECT WILL BE THE INTRODUCTION OF SOME CLOUDS OVER THE MOUNTAINS WITH SOME WEAK AFTERNOON CONVECTION POSSIBLE. AFTER TUESDAY...THE DISTRICT WILL REMAIN UNDER A TROF PATTERN THROUGH FRIDAY. ON FRIDAY...HEIGHTS START RECOVERING WITH AN AREA OF WEAKNESS REMAINING JUST OFFSHORE. YET... WILL STILL SEE TEMP/S RISE...SLOWLY...INTO THE WEEKEND. THE SHORTWAVE TROF WILL PUSH THROUGH TOO FAR NORTH TO REALLY INCREASE THE WINDS INTO THE ADVISORY OR WARNING CRITERIA LEVELS. THEREFORE...WINDS WILL NOT MUCH OF A CONCERN FOR THIS FORECAST PACKAGE AS SPEEDS WILL ONLY REACH THE NORMAL AFTERNOON BREEZY LEVELS. NO REAL CONCERNS IN THE LATER PERIODS OF THE FORECAST. LONGER RANGE MODELS DO SHOW ANOTHER TROF PUSHING INTO THE REGION BY EARLY NEXT WEEK. AT THE MOMENT...MODELS SHOW SOME DISAGREEMENT ON THE STRENGTH OF THE TROF...BUT ARE IN SOME AGREEMENT ON THE TIMING. WILL DO FURTHER ANALYSIS TO SEE HOW THIS NEXT TROF WILL INFLUENCE THE WEATHER OF NEXT WEEK. .HNX...NONE. MOLINA ca AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE DES MOINES IA 945 AM CDT MON JUN 17 2002 FORECAST PROBLEM THIS MORNING IS CONVECTIVE TRENDS. AREA OF MAINLY SHOWERS OVER WRN FA ATTM MOVG SE AHEAD OF S/WV. BASED ON WATER VAPOR IMAGERY...S/WV MOVE THRU NW IA AT 14Z SHOULD EXIT FA BY 20Z. LATEST RADAR TRENDS SUGGEST CONVECTION IS HOLDING TOGETHER AND WILL FORECAST IN THRU THE SE CWA EARLY. NEXT PROBLEM IS REDEVELOPMENT. MODELS NOT DO SO GOOD WITH THE DETAILS. BOTH THE RUC AND THE MESOETA FAILED TO HANDLE THE CURRENT CONVECTION SO THEIR SHORT TERM FORECAST TRENDS QUESTIONABLE. MOST LIKELY SCENARIO NOW IS NEXT S/WV...CURRENTLY EXITING MT...TO MOVE SE ACRS THE PLAINS. AMS FORECAST TO DESTABILIZE WEST OF IA NEAR SFC WARMFRONT. I THINK THIS AREA IS THE MOST LIKELY PLACE FOR DEVELOPMENT THIS AFTERNOON. 700-300 SHEAR VECTOR SHOWS A SE MOVEMENT INTO WRN IA THIS EVENING. INCREASING 850 MB LOW-LVL JET SW OFIA TONIGHT WOULD ENHANCE A S PROPAGATING SYSTEM. WILL KEEP HIGHEST POPS TONIGHT WEST BASED ON THIS. .DSM...NONE JOHNSON ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 215 PM EDT MON JUN 17 2002 SHORT TERM (TNGT-TUE): SCTD SHWRS/TSTMS HAVE DVLPD UPSTREAM ACRS NYS/PA...MOST OF IT CONCENTRATED FROM BUF-PIT ATTM. BOTH ETA/RUC TRY TO MAINTAIN THIS ACTVTY AS IT HEADS E LATE THIS AFTN...REACHING WRN PART OF FA AFT 21Z. PCPN HAS QUITE A DISTANCE TO TRAVEL TO MAKE IT THIS FAR E BEFORE SUNSET...BUT INCRSG TT AND TQ INDICES INTO ERLY TNGT SUGGEST AT LEAST REMNANT SHWRS WL MAKE IT IN HERE. ADDTL WDLY SCT SHWRS/TSTMS PRBLY WL FORM LATE THIS AFTN MNLY IN CT VLY AS WELL...AND ALREADY SOME WEAK ECHOES ARE SHOWING UP IN ERN NY. SO AM PLANNING TO CARRY MNTN INTO ERLY TNGT FOR AT LEAST WDLY SCTD SHWRS/TSTMS...BUT WL MAKE FINAL CALL BASED UPON LATEST RADAR AND INCORPORATE LATEST RUC INTO GFE. OTRW NOT MUCH FOR TNGT ONCE ACTVTY DIMINISHES. SHUD BE ANOTHER ROUND OF SCTD SHWRS/TSTMS TUE AFTN AND WL PLAY SCENARIO SIMILAR TO TDA WITH WKNG LN CNVTCN DSIPTG IN I-95 CORRIDOR LATE TUE AFTN. INSTABY SOMEWHAT LWR THAN IT IS TDA AND CAPES ARE LWR ALSO...BUT PASSING S/W SHUD BE ABLE TO INITIATE SOME CNVTCN DURG AFTN NONETHELESS. NO HEADLINES ON MARINE FCST WITH LGT WND FLO. MID TERM (WED-THU): PATTN QUIETS DOWN FOR MIDWK. BASED UPON 12Z ETA/AVN AM GOING TO REMOVE MNTN OF PCPN WED FM INTERIOR ZNS. DESPITE SOME DIURNAL INSTABY AS UPR TROF IS SLO TO DEPART...NOT MUCH OF A TRIGGER PRESENT TO GENERATE PCPN IN WEAK SFC FLO AS LL CONV REMAINS LIMITED. AVN THEN INDCTS WEAK BACKDOOR FNT DROPPING S THU MRNG WHICH IN ADDTN TO STABILIZING LO LVLS WL PREVENT TMPS FM GETTING TOO WARM AS UPR RDGE BLDS TO W. WL BACK OFF ON MAX TMPS THU GIVEN LL NE FLO. LONG TERM (FRI-MON): BIG QUESTION IS FCST FOR FRI AND BYD AND CONFIDENCE IS NOT VERY HI ATTM. PREVIOUSLY WAS LOOKING AT COUPLE OF CDFNTS ADVANCING E FM GRTLKS...ONE FRI NGT/SAT AND NXT MON. AS HINTED AT PAST FEW RUNS BY AVN...IT NOW CUTS OFF UPR LO OFF MIDATLC (IS THIS JUNE?) AS SFC LO ROTATES TWD CAPE COD AND SLWLY FILLS FRI. THIS WUD BRING RAIN WITH INCRSG NE WND TO AT LEAST ERN PART OF FA FRI AFTN/NGT...WITH LINGERING SHWRS AND DMNSHG WND SAT. AVN NOW SHOWS ENUF RDGG ON WRN PERIPHERY OF THIS SYS TO PREVENT FIRST CDFNT FM GETTING ANY FARTHER E THAN GRTLKS SAT. AM NOT GOING TO QUITE BUY INTO AVN SOLN JUST YET GIVEN MODEL DISPARITY THAT FAR OUT...AND WL ADJ ITS SOLN A LTL FARTHER S PER HPC...BUT FOR CONTINUITY AM GOING TO MAINTAIN CHC SHWRS FRI NGT/SAT AND KEEP SUN DRY (BUT MOCLDY) THEN HAVE ANOTHER CHC SHWRS MON WITH NEXT CDFNT. .BOX... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. JWD/BELK ma AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TAUNTON MA 1050 AM EDT MON JUN 17 2002 FCST UPDATED ERLR TO REMOVE MNTN OF FOG...OTRW NO SIG CHGS. STILL LOOKING AT POTL FOR AFTN CNVCTN THRUT FA...MAINLY IN THE 4 PM TO 8 PM TIMEFRAME. 12Z RUC AND 06Z ETA SHOW AMS DESTABILIZING DURG AFTN IN RESPONSE TO SFC HTG AND COOLG ALF...WHILE WEAK SFC TROF ADVANCES E FM NYS. BOTH MDLS APPEAR TO INITIATE DVLPMNT ERLY THIS AFTN ACRS NYS/PA...TIED TO CURRENT AREA OF CLDNS MOVG ACRS OH. SOUNDGS SHOW SURGE IN TT (INTO L50S) AND TQ (INTO L20S) LATE THIS AFTN/ERLY EVE WITH SB CAPES 500-100 J/KG...AXIS OF WHICH BCMS ALIGNED FM BDL-ORH-MHT AT 00Z/TUE. WND PROFILE REMAINS FAIRLY WK AND UNIDIRECTIONAL INTO TNGT...AND WET BULB ZERO HGT IS TOO LO TO SUPPORT SUFFICIENTLY LARGE HAIL. PRBLY LOOKING AT POTL FOR A COUPLE OF STORMS TO PRODUCE MARGINALLY SVR HAIL AND 50 MPH GUSTS...AND THIS FITS IN WITH SPC DAY1 OUTLK THINKG. XPCT STORMS TO WKN RAPIDLY AS WE APCH SUNSET...THO LEFTOVR SHWRS WL PRBLY LINGER THRU ERLY TNGT. DROPPED SCA FOR SEAS ALG SE OUTER WATERS. .BOX... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. JWD/CF ma AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1015 PM EDT MON JUN 17 2002 SKIES ARE CLR ACROSS FA THIS EVENING AS DRY AIR/SUBSIDENCE OVERSPREAD FA UNDER APPROACHING UPPER RIDGE AXIS OVER MN/ONTARIO PER WV IMAGERY/RUC ANALYSIS. SFC HIGH PRESSURE RIDGE EXTENDS FROM JAMES BAY ACROSS FA AND THRU WI. ALREADY UPDATED ZONES EARLIER THIS EVENING TO TAKE OUT EVENING SHRA NEAR LK MICHIGAN AND TO MAKE SLIGHT MODIFICATIONS TO SKY/WIND/TEMPS ELSEWHERE. ANOTHER UPDATE IS NOT NEEDED THIS EVENING. IDEAL RADIATIONAL COOLING CONDITIONS ARE IN PLACE TONIGHT UNDER CLOUDLESS SKIES/CALM WINDS. GUIDANCE NUMBERS IN THE LOW-MID 40S LOOK RIGHT ON TARGET AND ARE IN GOOD AGREEMENT WITH OBSERVED MINS THIS MORNING UNDER SFC RIDGE. CURRENT DWPTS ALSO SUPPORT MINS IN LOW/MID 40S. WOULDN'T BE SURPRISED TO SEE A FEW OF THE TYPICAL COLD SPOTS DIP INTO UPPER 30S OVER CNTRL FA. LIGHT DOWNSLOPING SERLY RETURN FLOW WILL DEVELOP FAR W OVERNIGHT...KEEPING MINS A COUPLE OF DEGREES HIGHER THERE. .MQT...NONE. ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 425 PM EDT MON JUN 17 2002 12Z RAOBS/LATEST WV LOOP RUC ANAL SHOW CONFLUENT NWLY UPR FLOW OVR THE NW GRT LKS BTWN A TROF IN THE E AND WHAT APPEARS TO BE A MORE PROGRESSIVE UPR RDG OVR THE NW PLAINS THAT IS DOWNWND OF A VIGOROUS SHRTWV COMING ASHORE IN THE PAC NW. SFC RDG OVR LK SUP/DRY AIRMASS UNDER UPR LVL CONFLUENCE BRINGING TRANQUIL...PLEASANT WX TO CWA TDAY. ONLY XCEPTION IS ACRS THE SRN TIER...WHERE SFC HTG/ENUF LINGERING LLVL HAVE CAUSED SOME ISOLD -SHRA. MSTR UPRSTREAM 12Z INL SDNG QUITE DRY...PWAT ARND 0.40 INCH. SOME TSRA NOTED ALG H85 THERMAL RDG IN THE NW PLAINS AS SHRTWV IN SASKATCHEWAN MOVG THRU UPR RDG. TSRA WEAKENING ATTM AS CNVCTN MOVG E INTO DRY...CONFLUENT NWLY FLOW FASTER THAN PATTERN IS SHIFTING E. XPCT TRANQUIL PD TNGT AS SFC HI/DRY AIRMASS ALF OVR INL AT 12Z DRIFT OVHD. AFTR ISOLD -SHRA OVR THE S DSPT TOWARD SUNSET WITH LACK OF ANY DYNAMICS TO OFFSET LOSS OF INSOLATION...LOOKS LIKE GOOD NGT FOR RADIATIONAL COOLING WITH LOWEST PWAT PASSING BY AND LGT WNDS NR RDG AXIS. NGM MOS FCST MINS COMPARE FVRBLY TO UPSTREAM RDGS THIS MRNG AND CURRENT DWPTS. AS RDG PASSES BY TO E...PRES GRADIENT PROGGED TO SHARPEN OVR THE W LATE...BUT NOT UNTIL RADIATION INVRN HAS HAD A CHC TO FORM. BUT LOWEST MINS WL BE OVR THE INTERIOR E AND CNTRL. AIRMASS TOO DRY FOR FOG PER MOS GUIDANCE. ON TUE...MODELS SHOW H5 HGTS BLDG OVR CWA AHD OF STRG PAC NW SHRTWV MOVG E INTO NRN PLAINS. SFC HI PROGGED TO DRIFT INTO THE ERN LKS. WITH SE FLOW PROGGED OUT OF THIS HI...THINK ETA IS TOO AGGRESSIVE AT INCRSG LLVL MSTR OVR THE CWA. THIS MODEL SHOWS DWPT REACHING 60 AT IWD BY LATE IN THE DAY. PREFER DRIER AVN FCST WITH DWPT ONLY GOING TO THE LO 50S AT IWD TOWARD 00Z. HAVE REMOVED MENTION OF POPS OVR THE W DURG LATE AFTN...AND CONFIDENCE INCRSD AS NO MODEL...NOT EVEN MOISTER ETA...GENERATES QPF AT IWD THRU 00Z AS PVA AHD OF WEAK SHRTWV COMING OUT OF SHRA COMPLEX IN THE NRN PLAINS THIS AFTN NOT ENUF TO PRODUCE ANY QVECTOR CNVGC UNDER RISING HGTS. GIVEN DRYNESS OF ANTECEDENT AIRMASS AND LACK OF SFC BNDRY AS INCRSG SSELY FLOW SUPPRESSES LK BREEZE OVR THE W UNDER ACYC H85 FLOW...DEEP CNVCTN APPEARS UNLIKELY. BUT THERE WL LIKELY BE REMNANT MID CLD MOVG IN WITH SHRTWV...SO FCST OF BECMG PSUNNY IN THE AFTN THERE APPEARS ON TRACK. FARTHER E...XPCT JUST SOME SCT CU. SINCE AVN HAD BEST 12Z INITIALIZATION ON H85 TEMPS UPSTREAM...USED ITS FCST TEMPS TO ESTIMATE MAX TEMPS TMRW. FULL MIXING TO H85 (ADD 14C TO FCST H85 TEMP AS HI AS 12C AT IWD) YIELDS MAX TEMP ARPCHG 80 AT IWD...WITH DOWNSLOPE SSELY FLOW ENHANCING WRMG THERE...TO ARND 75 AT ERY. XPCT LWR READINGS DOWNWND OF LK MI WITH SELY FLOW. ALL MODEL MOS FCST TEMPS ARE QUITE A BIT LWR AS FCST SDNGS SHOW MIXING NOT ACHIEVED THRU H85. BUT FCST INCRSG SSELY GRADIENT FLOW SHUD ENHANCE MIXING PROCESS...SO HAVE OPTED TO MAINTAIN CONTINUITY AND ABV LWR MOS FCSTS. CONFIDENCE INCRSD AS SFC TEMPS IN MN RISING QUICKLY THRU THE 70S THIS AFTN. ATTENTION AFTR TMRW THEN TURNS TO IMPACT OF STRG PAC NW SHRTWV. ETA HAS TRENDED SLOWER WITH EWD MVMNT OF SYS...NOT SURPRISING CONSIDERING SLUGGISH TROF OVR THE E. AVN FCST HAS BEEN MUCH MORE CONSISTENT SHOWING SLOWER/DEEPER ERN TROF...SO FOLLOWING ITS GUIDANCE FOR TIMING. MODELS ALL ADVERTISE RISING HGTS OVR CWA TMRW NGT WITH INCRSG PRES GRADIENT OVR THE CWA AS PRES FALLS OVR THE NRN PLAINS IN ADVANCE OF SHRTWV. ETA MOST AGGRESSIVE AT PUSHING PCPN INTO CWA AND APPEARS TO DVLP WAD MCS OVR THE ECNTRL. AVN/CNDN/NGM RESTRICT QPF TO FAR WRN ZNS...CONSISTENT WITH SHARPENING RDG/DEEP LYR QVECTOR DVGC/ H4-2 CNVGC OVR MOST OF CWA DEPICTED BY AVN. SINCE ETA IS TOO PROGRESSIVE WITH MSTR/SYS SPEED HAVE RESTRICTED MENTION OF POPS TO WRN COUNTIES OF CWA. STEADY WND AND AT LEAST PTCHY MID/HI CLDS WL KEEP TEMPS MUCH HIER THAN TNGT...A COMPROMISE BTWN HIER NGM/ETA MOS AND LWR AVN GUIDANCE XCPT OVR THE FAR W...WHERE HIER ETA FCST RSNBL FOR SLY FLOW. AVN CONTS TO AMPLIFY PATTERN ON WED INTO THU AND IS VERY RELUCTANT TO PUSH PCPN E THRU CWA...WITH COLD FNT ASSOCIATED WITH SHRTWV TO THE W NOT PUSHING INTO CWA UNTIL THU...WHEN SHRTWV AND DEEPEST MSTR PULL NE INTO ONTARIO. TO MAINTAIN SOME CONTINUITY WITH PREVIOUS FCST...HAVE NOT PUSHED POPS BACK AS FAR AS AVN WOULD SUG. BUT HAVE RESTRICTED POPS TO THE WRN HALF OR SO OF CWA THRU THU AT MIDNGT... THEN CHCY POPS FOR SHRA/TSRA ALL DAY THU AS BNDRY REMAINS FOCAL PT FOR CNVCTN DESPITE BEST DYNAMICS/MSTR LIFTING NE. MOS GUIDANCE TEMPS LOOK RSNBL. EXTENDED MODELS ALL SHOW A TREND TOWARD LWR HGTS IN THE W AND HIER HGTS IN THE E...WITH THE RESULT A MORE SUMMERLIKE PATTERN FOR THE CWA AS THE MAIN UPR JET OVR ERN NAMERICA RETREATS N INTO CAN. OPERATIONAL MODELS AND ENSEMBLE MEANS ALSO IN FAIRLY GOOD AGREEMENT ON DAY-TO-DAY WX AS WELL. HI PRES/DRIER AIR IN WAKE OF THU SHRTWV/FNT MOVE IN FOR FRI. OPERATIONAL MRF SHOWS NXT SHRTWV IMPACT CWA ON SAT WITH DRIER AIR MOVG IN ON SUN...BUT WL FOLLOW MAJORITY OF SLOWER MRF ENSEMBLE MEMBERS AND OTHR OPERATIONAL MODELS AND GO WITH PCPN CHCS LINGERING INTO SUN. MODELS HINT AT ANOTHER DRY AIRMASS FOR MON WITH UPR JET IN ERN CAN SINKING A BIT FARTHER S AND BCMG MORE NWLY. PREVIOUS EXTENDED FCST IN PRETTY GOOD SHAPE...SO FEW CHGS NECESSARY. COORDINATED WITH APX/GRB. .MQT...NONE. KC mi SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1115 AM EDT MON JUN 17 2002 UPDATE FOCUS IS ON THUNDERSTORM POTENTIAL. WATER VAPOR LOOP SHOWS TWO WEAK VORT CENTERS SWINGING AROUND THE UPPER LOW CURRENTLY MOVING INTO QUEBEC. ONE OVER SOUTHEAST LOWER LEADING TO AN AREA OF SHOWERS/ISOLATED THUNDERSTORMS JUST CLEARING OUT OF THE METRO DETROIT AREA. NEXT VORT UPSTREAM MOVING INTO NORTHERN LOWER AND WILL BE OF INTEREST FOR THE AFTERNOON/EVENING...WITH A FEW SHOWERS ALREADY APPARENT NORTHWEST OF THE CWA. SURFACE ANALYSIS SHOWS A WEAK TROUGH CROSSING LOWER MICHIGAN FROM CENTRAL LAKE MICHIGAN TO CENTRAL LAKE HURON. OTHER THAN THE MORNING CONVECTION...EARLY VISIBLE SATELLITE SHOWS MOSTLY SUNNY SKIES ACROSS THE REMAINDER OF THE CWA. 12Z RUC/ETA DROP THE NORTHERN VORT INTO THE CWA THIS EVENING...WITH A WEAK FRONT/WAVE AT THE SURFACE. GENERALLY A WEAK GRADIENT BUT WITH BOTH RUC/ETA DEPICTING SOME 925MB CONVERGENCE INTO THE EVENING. INSTABILITY WILL BE A QUESTION FOR THE AFTERNOON WITH -23C COLD POOL AT 500MB SHIFTING EAST WITH WARM ADVECTION BEGINNING. HOWEVER 850-500MB LAPSE RATES STILL NEAR 7C/KM. DEWPOINTS IN THE LOWER 50S POOLING ALONG THE TROUGH AFTER MORNING RAIN SHOWERS...WITH TEMPERATURES CLIMBING INTO THE LOWER 70S. MODIFIED 12Z DTX SOUNDING FOR T/TD OF 72/52 WOULD YIELD 2500J/KG OF CAPE. HOWEVER WITH WARM ADVECTION THE GRB SOUNDING WOULD BE MORE REPRESENTATIVE OF THE AFTERNOON AIRMASS...AND YIELDS 1300J/KG CAPE WITH SAME INITIAL T/TD. UPPER DIVERGENCE NOT THAT IMPRESSIVE...ALTHOUGH CWA LOCATED NEAR GENERAL LEFT-EXIT OF 60KT 300MB JET. WILL KEEP A CHANCE OF THUNDERSTORMS FOR THE AFTERNOON CARRIED INTO THE EVENING. CLIMBING FREEZING LEVELS WITH THE WARMING COLUMN IN ADDITION TO MARGINAL WIND FIELDS AND INSTABILITY SHOULD PRECLUDE SEVERE WEATHER. WITH LINGERING LOW-LEVEL MOISTURE AND GENERALLY STEEP LAPSE RATES WITH THERMAL THROUGH STILL JUST SHIFTING EAST...EXPECT DECENT CU TO DEVELOP BY AFTERNOON LEADING TO PARTY SUNNY SKIES. .DTX...NONE. BRAVENDER mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 930 PM CDT MON JUN 17 2002 MAIN PROBLEM FOR THE OVERNIGHT HOURS IS POTENTIAL FOR TSTMS WITH INCREASE IN THE LOW LEVEL JET. OAX SOUNDING THIS EVENING WAS NOT OVERLY IMPRESSIVE...BUT THERE WAS SOMEWHAT OF A MOIST LAYER JUST BELOW 850 MB. MODELS CONTINUE TO FCST INCREASE IN THE LOW LEVEL JET OVERNIGHT...BUT WILL IT BE ENOUGH TO OVERCOME THE LIMITED AMOUNT OF LOW LEVEL MOISTURE. SOME STORMS WERE DEVELOPING OVER IN CNTRL IA AS OF 925 PM...BUT EAST OF OUR AREA. 00Z ETA OUTPUT DOES GENERATE SOME LGT PCPN OVER THE AREA LATE TNGT INTO TUE MORNING. NGM IS EVEN MORE AGRESSIVE...OVER SERN NE AND SWRN IA. SO...WILL LOWER POPS JUST SLIGHT IN NERN NE AND INCREASE THEM IN SERN NE/SWRN IA. REST OF FCST BASICALLY UNCHANGED. MILLER ... 310 PM DISCUSSION FCST CONCERNS ARE TSTM CHCS INTO TUE THEN HOW FAR S AND HOW FAST WK FRONTS WL PUSH INTO FCST AREA THU AND AGAIN SUN. SHORT TERM...19Z STLT SHOWED ACCAS CLOUD BAND DROPG SE TWD CWA AHD OF A SHORTWV TROF IN NWRLY UPR FLOW...A GOOD INDICATION OF SYNOPTIC SCALE LIFT MODELS HAVE BEEN FCSTG FOR SVRL RUNS NOW. THIS TROF/MAX WL BE MOVG TWD A INSTABILITY AXIS THAT RUC FCSTS AT 00Z TO LIE FM SW OF LNK INTO NERN NEBR...WHICH IS SUPPORTED BY LATEST LAPS TRENDS. WOULD EXPECTED TSTMS TO DVLP BFR 06Z AIDED BY MODERATELY STG/INCRSG LOW LVL JET. ONLY DRAWBACKS ARE A NARROW BAND OF DRIER SFC DWPTS ARND LNK AND FET S INTO KS AND THE FACT LATEST RUC DOESN'T FCST PCPN OVER CWA UNTIL 03Z-06Z TIME PERIOD AND THEN MAINLY EITHER NE OR SW OF CWA. NONETHELESS WL RUN 40-50 PERCENT POPS AREAWIDE...HIGHEST S...AND MAY HAVE TO GO CATEGORICAL IF CONVECTION DVLPS BFR PRESSTIME. LTL CHANGES TO TNGTS LOWS. WHETHER CONVECTION DVLPS TUE/TUE EVENING WILL DEPEND A LARGE DEGREE ON WHETHER OR NOT OVERNIGHT CONVECTION CAN KEEP A BNDRY IN THE AREA SINCE WARMING MID LVL TEMPS WL CREATE A STGR CAP ACRS THE AREA PER BUFKIT SOUNDINGS. HOWEVER...BOTH AVN AND ETA DO SUGGEST THIS IS QUITE PSBL SO WL KEEP TSTM CHCS IN FCST...ALTHO OUTSIDE OF MORNING ACTIVITY DOUBTS DO EXIST. BECAUSE OF THE COOL OUTFLOW FCST BY ETA/AVN TRIMMED BACK HIGHS A LTL. KEPT SMALL POPS IN TUE EVENING MAINLY N THEN DRY TIL LATE AFTN WED NWRN ZONES. WL BASE WED THRU THU FCST BASED ON SLOWER ETA AS FRONT WILL BE TRYING TO PUSH SE UNDER BUILDING UPR RIDGE. THUS MOST ZONES COULD BE WINDY AND QUITE WARM WED AND BOOSTED TEMPS. DID NOT GO QUITE AS WARM AS ETA ATTM...BUT THIS TREND WL HAVE TO BE WATCHED. ALSO CONTD TEMPS A LTL ABV AVN MOS ON THU ACRS THE S DUE TO A SLOWER FROPA. DAYS 4-7...AS PER NCEP DISC...AFTER FRONT LIFTS N/DISPTS LATE FRI WL GO WITH A SLOWER SOLUTION WITH NEXT FRONT THAT WL TRY TO WORK ITS WAY THRU CWA THIS WEEKEND. THE FRONT WILL BE FIGHTING SWD THRU 500 MB HGTS IN EXCESS OF 5880 M AS THE SHORTWV DRIVING IT WILL BE WELL TO OUR N. THUS WILL RAISE HIGHS SLIGHTLY THIS WEEKEND WITH HIGHEST POPS FRI AND LOWER SAT INTO MON. CHERMOK .OMA...NONE. MILLER ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 310 PM CDT MON JUN 17 2002 FCST CONCERNS ARE TSTM CHCS INTO TUE THEN HOW FAR S AND HOW FAST WK FRONTS WL PUSH INTO FCST AREA THU AND AGAIN SUN. SHORT TERM...19Z STLT SHOWED ACCAS CLOUD BAND DROPG SE TWD CWA AHD OF A SHORTWV TROF IN NWRLY UPR FLOW...A GOOD INDICATION OF SYNOPTIC SCALE LIFT MODELS HAVE BEEN FCSTG FOR SVRL RUNS NOW. THIS TROF/MAX WL BE MOVG TWD A INSTABILITY AXIS THAT RUC FCSTS AT 00Z TO LIE FM SW OF LNK INTO NERN NEBR...WHICH IS SUPPORTED BY LATEST LAPS TRENDS. WOULD EXPECTED TSTMS TO DVLP BFR 06Z AIDED BY MODERATELY STG/INCRSG LOW LVL JET. ONLY DRAWBACKS ARE A NARROW BAND OF DRIER SFC DWPTS ARND LNK AND FET S INTO KS AND THE FACT LATEST RUC DOESN'T FCST PCPN OVER CWA UNTIL 03Z-06Z TIME PERIOD AND THEN MAINLY EITHER NE OR SW OF CWA. NONETHELESS WL RUN 40-50 PERCENT POPS AREAWIDE...HIGHEST S...AND MAY HAVE TO GO CATEGORICAL IF CONVECTION DVLPS BFR PRESSTIME. LTL CHANGES TO TNGTS LOWS. WHETHER CONVECTION DVLPS TUE/TUE EVENING WILL DEPEND A LARGE DEGREE ON WHETHER OR NOT OVERNIGHT CONVECTION CAN KEEP A BNDRY IN THE AREA SINCE WARMING MID LVL TEMPS WL CREATE A STGR CAP ACRS THE AREA PER BUFKIT SOUNDINGS. HOWEVER...BOTH AVN AND ETA DO SUGGEST THIS IS QUITE PSBL SO WL KEEP TSTM CHCS IN FCST...ALTHO OUTSIDE OF MORNING ACTIVITY DOUBTS DO EXIST. BECAUSE OF THE COOL OUTFLOW FCST BY ETA/AVN TRIMMED BACK HIGHS A LTL. KEPT SMALL POPS IN TUE EVENING MAINLY N THEN DRY TIL LATE AFTN WED NWRN ZONES. WL BASE WED THRU THU FCST BASED ON SLOWER ETA AS FRONT WILL BE TRYING TO PUSH SE UNDER BUILDING UPR RIDGE. THUS MOST ZONES COULD BE WINDY AND QUITE WARM WED AND BOOSTED TEMPS. DID NOT GO QUITE AS WARM AS ETA ATTM...BUT THIS TREND WL HAVE TO BE WATCHED. ALSO CONTD TEMPS A LTL ABV AVN MOS ON THU ACRS THE S DUE TO A SLOWER FROPA. DAYS 4-7...AS PER NCEP DISC...AFTER FRONT LIFTS N/DISPTS LATE FRI WL GO WITH A SLOWER SOLUTION WITH NEXT FRONT THAT WL TRY TO WORK ITS WAY THRU CWA THIS WEEKEND. THE FRONT WILL BE FIGHTING SWD THRU 500 MB HGTS IN EXCESS OF 5880 M AS THE SHORTWV DRIVING IT WILL BE WELL TO OUR N. THUS WILL RAISE HIGHS SLIGHTLY THIS WEEKEND WITH HIGHEST POPS FRI AND LOWER SAT INTO MON. .OMA...NONE. CHERMOK ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 930 PM EDT MON JUN 17 2002 WILL MAKE MINOR CHGS TO CURRENT FCST. WILL LWR POPS ACRS THE AREA TO 20% AND MENTION SHRA ONLY. RUC INDICATES WK H5 VORT MOVG INTO RGN OVERNIGHT FM THE SW WITH SOME OMEGA AFT 06Z. OTRW LGT WINDS...MOCLDY SKIES...AND MINS TNGT FM THE UPR 60S TO THE LWR 70S. MARINE...MINOR CHGS TO WS AND WD OVERNIGHT. SLY WINDS 10 KT OR LESS AND SEAS 3 FT OR LESS. .CHS... GA...NONE. SC...NONE. JAC sc AREA FORECAST DISCUSSION FOR CENTRAL/N-EAST SD AND W-CENTRAL MN NATIONAL WEATHER SERVICE ABERDEEN SD 835 PM CDT MON JUN 17 2002 CONVECTION STILL STRUGGLING TO GET STARTED THIS EVENING ACROSS THE CWA. LATEST MSAS ANALYSIS SHOWS AN AREA OF LOW LVL MSTR CONVERGENCE OVER THE CENTRAL AND EASTERN PORTIONS OF THE CWA...BUT BEST MID/UPR LVL FORCING STILL WELL TO THE WEST AND NORTHWEST OF THE REGION. SOME ACTIVITY IN NODAK...BUT THIS APPEARS RATHER BENIGN. BETTER SHORT WAVE SITUATED IN EASTERN MT...WHERE STRONGER TSTMS ARE. AS THIS SHORT WAVE MOVES INTO THE REGION LATER TONIGHT WOULD EXPECT SOME ACTIVITY TO DEVELOP. RUC STILL SHOWING A FAIRLY STRONG LLJ DEVELOPING ACROSS THE ERN CWA LATE TONIGHT. THIS ALSO IS AREA OF BEST LOW LVL THETA E. WILL LEAVE MENTION OF TSTMS ACROSS THE ENTIRE CWA...BUT THINK ERN PORTIONS HAVE THE BEST CHANCE LATER TONIGHT. HAVE UPDATED TO TWEAK THE WINDS OUT WEST AS SPEEDS HAVE REMAINED HIGHER THAN ORIGINALLY ANTICIPATED. .ABR...NONE. FAUCETTE sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 903 PM CDT MON JUN 17 2002 CURRENTLY, SKIES ARE MOSTLY CLEAR ACROSS THE MID STATE, WITH RIDGE AXIS ABOUT TO MOVE ACROSS THE AREA. TEMPERATURES AREN'T COOLING AS MUCH AS EXPECTED SO HAVE AMENDED ZONE FORECAST PRODUCT TO RAISE OVERNIGHT LOWS EVERYWHERE BUT THE NORTHERN PLATEAU. USING THE 1000-925 MB THICKNESS EQUATION ON 12Z ETA AND 00Z RUC GIVES AN OVERNIGHT LOW OF 63 AT BNA. EVENING SOUNDING SHOWS A DRY, BUT UNSTABLE ATMOSPHERE IN PLACE. WE SHOULD SEE SOME LOW-LEVEL WARMING TOMORROW WITH RETURN SOUTHERLY FLOW ON THE WAY. .BNA...NONE. ROSE tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 1101 AM EDT MON JUN 17 2002 WILL OPT TO UPDATE ZFP TO MAKE MOSTLY SOME MINOR CHANGES TO THE FIRST PERIOD. STORM SYS TO MOVE TO THE NORTH OF THE FA TODAY AND TONITE...AS A HI PRESS RIDGE BUILDS ACRS THE GREAT LKS REGION. FEW SPOKES OF VORTICITY TO SWING UP ACRS THE FA FROM THE SW TODAY. 09Z RUC SHOWS TEMPS TO BE AROUND 60F TO THE M70S TODAY WITH W-SW SFC WINDS AT 5-15 KTS. T1MAX TEMPS ARE 65-75F TODAY. FEW TWEAKS TO FIRST PERIOD TEMPS/WINDS BASED ON THIS DATA AND CURRENT OBS. BEST MID-LVL (AND LOW-LVL) MSTR TO BE LOCATED ACRS THE NRN TIER ZONES TODAY AND TONITE. SOME LOW-LVL MSTR FLUX CONVERGENCE TO AFFECT THE FA THIS AFTERNOON. MODEL DATA SHOWING PW VALUES TO BE BLO AN INCH ACRS THE FA TODAY...AND 2 FSL GPS IPW SITES IN NH/NY INDICATING IPW VALUES OF 0.8-1" ATTM. RUC SHOWS PCPN COVERAGE TO INCREASE ACRS THE FA TODAY... WITH AOB 0.25" OF QPF EXPECTED. NOT MUCH PCPN COVERAGE AT ALL IN RADAR DATA ATTM...BUT PCPN EXPECTED TO POP UP THIS AFTERNOON WHEN DYNAMIX START TO AFFECT THE FA. WILL HANG ONTO LIKELY POPS ACRS NRN TIER ZONES AND CHC POPS ACRS SRN VT. CHC POPS STILL LOOK LIKE A GOOD IDEA FOR TONITE. H85 CAA TO TAKE PLACE ACRS THE FA TODAY AND TONITE. LOW-LVL LAPSE RATES TO BE HI ACRS THE FA TODAY AND TONITE. MID-LVL LAPSE RATES TO BE HI ACRS THE FA THIS AFTERNOON AND TONITE. NOTED SPC GEN TSTM OUTLOOK HIGHLIGHTING THE FA TODAY AND TONITE. CAPES TO BE 200-800 J/KG ACRS THE FA TODAY. ENVIRONMENT APPEARS TO BE AT LEAST MODERATELY SHEARED ACRS THE FA TODAY...WITH WET-BULB ZERO HTS EVEN LOWER THAN YESTERDAY (5.5-6.0 KFT). DAMAGING WIND PARAMETERS APPEAR TO BE MARGINAL WITH AT LEAST SOME MORE MID-LVL DRYING ACRS THE FA TODAY THAN YESTERDAY...BUT LOWER PW VALUES. WILL LEAVE CHC OF TSRA IN THE ZONES FOR TODAY WITH NO ENHANCED WORDING. HYDRO-WISE...QPE OVER THE LAST 24 HRS APPEARS TO HAVE BEEN AOB 0.25" (WITH SOME LOCALLY HIR AMTS IN ANY +SHRA/TSRA YESTERDAY). 1-3 HR FFG VALUES OF 1-2" NOT EXPECTED TO BE EXCEEDED TODAY OR TONITE. WRK ZONES OUT UNDER ALBWRKCWF. FINAL ZFP ASAP. .BTV...NONE. MURRAY vt EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 200 AM EDT TUE JUN 18 2002 CURRENT...SFC ANLYS/METARS INDICATE THAT THE LOW LEVEL RIDGE AXIS APPEARS TO HAVE MIGRATED NORTH TO NEAR THE LAT OF LAKE OKEE. KMLB 88D SHOWS THE ERSTWHILE CONVECTIVE COMPLEX WHICH HAD BEEN MOVING ACROSS THE STATE HAS DEGENERATED INTO PATCHY LIGHT DEBRIS RAIN WITH A FEW CONVECTIVE CELLS NOTED ACROSS MARTIN COUNTY ATTM. WIDESPREAD MID/UPPER LEVEL CONVECTIVE DEBRIS NOTED ON 3.9UM IR...THOUGH A BIT FARTHER NORTH (N OF KAPF-KVRB LINE) THAN THE PAST FEW NIGHTS. WATER VAPOR/RUC UPR STRMLINE VORT ANLYS SHOW UPSTREAM VORT AXIS OVER THE CENTRAL GOMEX CROSSING 90W WITH CENTERS NEAR 29N AND 25N. METARS TRACE OUT A WEAK 1010MB LOW OVER THE GOMEX SOUTH OF KMSY. 00Z RAOBS INDICATED RELATIVELY DRIER AIR ACROSS SOUTH FL/KEYS (PWATS ~1.7") COMPARED TO THE NRN/CTRL PENIN (1.9"-2.1"). H50 TEMPS PROGGED TO REMAIN SIMILAR TO 00Z...-9C OVER ECFL AND 1C COOLER N/WARMER S... SO A FEW STRONG STORMS WILL BE POSSIBLE ALONG MESO BOUNDARIES. TODAY/TONIGHT...LOW LEVEL RIDGE WILL CONTINUE ITS' SLOW NWD TREK... WHILST THE DLM ATLC RIDGE STRENGTHENS AND EXPANDS NWD. THIS MEANS THAT THE SFC FLOW WILL BACK SOME (SOUTH RATHER THAN SW) TODAY WHILE AT THE UPPER LEVELS THE GOMEX TROUGH WILL SHEAR NNE RATHER THAN PROGRESS E OR NE. THUS MID LEVEL VORT ENERGY WILL FOCUS MORE ACROSS NORTH FL RATHER THAN FARTHER SOUTH. NEVERTHELESS...H25 JTSTRK /DIVG CONTRIBUTIONS TO UVM REMAIN STRONG...HENCE THE SYNOPTIC PROFILE WILL REMAIN ASCENDANT. THEREFORE...FCST FOR ABOVE CLIMO POPS LOOKS FINE. SLIGHT DRYING INDICATED BY THE AVN ALONG THE SE COAST APPEARS IN LINE WITH RAOBS. ECSB SHOULD BE PRETTY ACTIVE IN AND OF ITSELF WHILE STEERING LAYER FLOW TRIES TO KEEP ACTIVITY MOVING BACK TWD THE COAST IN SPITE OF THE INLAND PROGRESSION OF THE SEA BREEZE. WED/THU...BUILDING RIDGE WITH DEEP LAYER FLOW BACKING AND BECOMING MORE ANTICYCLONIC. WITH INCREASING S-SE COMP AT ALL LEVELS...HIGHER RAIN CHANCES WILL SHIFT WWD TO THE INTERIOR/WRN PENIN. HOWEVER... ALL THE SHORT RANGE GUIDANCE (ESP THE AVN) SHOWS AN EASTERLY TWAVE APPROACHING 80W LATE WED AFTERNOON/EVENING WITH SIGNIFICANT ENOUGH AMPLITUDE TO INCREASE MEAN PWATS BACK UP BY A FEW TENTHS ACROSS THE SOUTH...WHERE DRYING WAS MOST PRONOUNCED TO BEGIN WITH. PLAN TO QUALITATIVELY FAVOR THE AVN (THOUGH NOT COMPLETELY) AND NUDGE POPS BACK UP TO 50 FOR THU...THOUGH IF IT WERE TO VERIFY 100%...IT WOULD MAKE FOR AN ACTIVE NOCTURNE FOR MUCH OF E/SE FL WED NIGHT AND HIGHER POPS (LIKELY?) THU...ESP DURING THE MORNING. FRI-MON...LOW LEVEL RIDGE AXIS TAKES UP RESIDENCE NORTH OF FLORIDA WITH MODERATE DEEP LAYER ESE FLOW BECOMING FIRMLY ENTRENCHED ACROSS ECFL. THIS WILL KEEP US IN A NIGHTTIME/MORNING CONVECTIVE REGIME ALONG THE COAST...AND A LATE EARLY-MID AFTERNOON REGIME OVER THE INTERIOR. MARINE...NO HIGHLIGHTS. BENIGN CONDITIONS AT 41009 W/ SEAS DOWN TO ~1FT AND WINDS BLO 10KT. MAIN CONCERN TODAY WILL BE STRONG LTG STORMS ESP NEAR THE INTRACOASTAL WATERS. WINDS WILL GRADUALLY BACK THROUGH THE PERIOD AS MENTIONED EARLIER...BUT WILL STAY BELOW SCA LEVELS. COORD W/ MIA. PRELIMINARY CCF... DAB TB 086/072 088/073 085 73435 MCO TB 087/072 090/072 087 73435 MLB TB 086/074 087/075 085 63445 60= .MLB...NONE. PUBLIC/MARINE...CRISTALDI AVIATION/FIRE WX...VOLKMER fl SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 246 AM EDT TUE JUN 18 2002 A SHORT WAVE TROUGH IS LOCATED OVER SOUTHEAST MICHIGAN PER CURRENT WATER VAPOR LOOP...WITH THE BEST UPPER SUPPORT WELL EAST OF THE FORECAST AREA. SUBSIDENCE IN THE WAKE OF THIS SHORT WAVE ALONG WITH SHARP UPPER RIDGE BUILDING INTO THE WESTERN GREAT LAKES IS PROVIDING PLENTY OF LARGE SCALE SUBSIDENCE OVER THE WESTERN/CENTRAL GREAT LAKES. THERE IS A WEAK SURFACE TO 850MB FRONTAL BOUNDARY OVER NE ILLINOIS AND NRN INDIANA. LOW LEVEL CONVERGENCE ALONG THIS FEATURE HAS BEEN PROVIDING SOME SHOWERS AND SCT THUNDERSTORMS EXTENDING FROM SE WISCONSIN TO NE OHIO. MID LEVEL DRYING NOTED ON THE WATER VAPOR LOOP MAY BE ENHANCING THE CONVECTIVE POTENTIAL ALONG THIS FRONTAL BOUNDARY. BOTH THE RUC AND MESO ETA KEEP THE CONVERGENCE ALONG THIS BOUNDARY SOUTH AND WEST OF THE FORECAST AREA THIS MORNING AND WEAKEN IT CONSIDERABLY. THE LATEST RADAR AND SATELLITE TRENDS SUPPORT THIS...THUS I DO NOT EXPECT ANYTHING OTHER THAN SOME MID LEVEL CLOUDS TO GRAZE THE SOUTHERN COUNTIES THIS MORNING. THE 00Z MODELS CONTINUE TO SHOW FAIRLY GOOD AGREEMENT AND CONSISTENCY IN BRINGING UPPER LEVEL RIDGING ACROSS THE REGION OVER THE NEXT 36 HOURS. AT THE SURFACE...HIGH PRESSURE OVER THE NORTHERN LAKES WILL SLOWLY SLIDE EAST OF THE REGION BY MIDWEEK...WITH RETURN FLOW AROUND THE HIGH BRINGING MUCH WARMER AND MORE HUMID AIR TO SOUTHEAST MICHIGAN. FOR TODAY...500MB TEMPS SLOWLY WARM AS THE UPPER TROUGH HEADS EAST OF THE REGION. THIS WILL ALLOW MID LEVEL LAPSE RATES TO DECREASE FROM AROUND 7C/KM THIS MORNING TO AROUND 6C/KM BY LATE AFTERNOON. WITH THE LARGE SCALE SUBSIDENCE OVERHEAD AND MODEL SOUNDINGS DEVELOPING A CAPPING INVERSION ABOVE 700MB THIS AFTERNOON...A DRY FORECAST STILL LOOKS WARRANTED. SFC TO 850MB LAPSE RATES REMAIN QUITE STEEP...ENOUGH TO PROVIDE SOME AFTERNOON CU POTENTIAL. LOW LEVEL MOISTURE WILL REMAIN LIMITED ENOUGH THOUGH TO KEEP A MOSTLY SUNNY FORECAST. YESTERDAY AFTERNOON MIXING HEIGHTS ON UPSTREAM SOUNDINGS WERE GENERALLY AROUND 4K FT. BASED ON MODEL SOUNDINGS FOR THIS AFTERNOON...MIXING TO THIS LEVEL SHOULD PROVIDE HIGHS IN THE MID 70S. A WEAK SURFACE GRADIENT WILL ALLOW LAKE BREEZES TO DEVELOP...KEEPING LOCATIONS NEAR THE GREAT LAKES SEVERAL DEGREES COOLER. TONIGHT...THE ETA SHOWS SOME THETA-E ADVECTION FROM 850-700MB. WITH THE UPPER LEVEL RIDGE RIGHT ON TOP OF LOWER MICHIGAN THOUGH...I DO NOT EXPECT ANYTHING MORE THAN FEW-SCT MID LEVEL CLOUDS OVERNIGHT. AN INCREASING GRADIENT OVERNIGHT SHOULD PREVENT TEMPS FROM FALLING AS LOW AS THE PAST COUPLE OF NIGHT. ETA SOUNDINGS ON BUFKIT SHOW A 20-25KT WIND MAX DEVELOPING OVERNIGHT AROUND 1K FT. LOOKING AT THE MOMENTUM TRANSPORT...THIS DOES NOT MAKE IT TO THE SURFACE SO I EXPECT WINDS WILL REMAIN FAIRLY LIGHT. WEDNESDAY THROUGH THURSDAY...A SOUTHERLY GRADIENT WILL BE IN PLACE ACROSS THE AREA ON THE BACK SIDE OF THE SURFACE HIGH...WITH HEIGHTS AT 500MB ON THE RISE. THIS WILL SPELL A WARMING TREND. GUIDANCE HIGHS OF LOW-MID 80S ON WEDNESDAY AND MID-UPPER 80S ON THURSDAY SEEMS REASONABLE GIVEN THE 850MB TEMPERATURE PROGS. WITH ALL OF THE UPPER SUPPORT STILL WELL WEST OF THE FORECAST AREA...I WILL MAINTAIN A DRY FCST. THE LATEST CANADIAN RUN KEEPS AN APPROACHING FRONTAL BOUNDARY NORTH OF THE FORECAST AREA ON FRIDAY...WHILE THE AVN BRINGS IT INTO THE NORTHERN COUNTIES (TRENDING FARTHER NORTH FROM THE PREVIOUS RUN). GIVEN THE FAIRLY ZONAL FLOW ALOFT AND WEAK UPPER RIDGING OVER THE SOUTHERN GREAT LAKES...I LIKE THE CANADIAN IDEA OF KEEPING THE FRONT NORTH. AT THIS POINT...I WILL LEAVE POPS IN FOR ALL AREAS ON FRIDAY AND LET AN ADDITIONAL MODEL RUN DECIDE IF POPS NEED TO BE REMOVED FROM AT LEAST THE SOUTHERN COUNTIES. .DTX...NONE. CONSIDINE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BUFFALO NY 316 AM EDT TUE JUN 18 2002 THE SHORT WAVE THAT IS CURRENTLY PUSHING THROUGH WESTERN LAKE ERIE EARLY THIS MORNING IS STILL GENERATING A FEW SHOWERS AND SCATTERED THUNDERSTORMS OVER NORTHWEST PA. AS THE SHORT WAVE TRACKS EAST ACROSS THE SOUTHERN TIER LATER THIS MORNING IT MAY SET OFF A FEW SHOWERS OR THUNDERSTORMS...BUT THE REST OF THE FA SHOULD REMAIN DRY. THE RUC SHOWS ANOTHER IMPULSE APPROACHING WESTERN NEW YORK TOWARD LATE AFTERNOON...BUT IT LOOKS LIKE THE BEST MOISTURE CONVERGENCE WILL BE EAST OF OUR FA...SO I WILL NOT MENTION ANY AFTERNOON THUNDERSTORMS. THE MAIN WEATHER STORY IS THAT THE STUBBORN LOW THAT BROUGHT OCCASIONAL SHOWERS AND THUNDERSTORMS TO OUR AREA THE PAST THREE DAYS WILL FINALLY LOOSE ITS GRIP ON OUR AREA. THE WEAK RIDGE THAT IS BUILDING IN BEHIND THE LOW WILL BRING INCREASING SUNSHINE THE NEXT THREE DAYS ALONG WITH A CORRESPONDING MODERATION IN TEMPERATURE THAT IS MORE IN LINE WITH THE SEASON. THE NEXT BEST CHANCE FOR ANY RAIN WILL COME FRIDAY WHEN A WEAK COLD FRONT IS FORECAST TO PUSH EAST ACROSS THE STATE. .BUF...NONE. TJP ny SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1104 AM EDT TUE JUN 18 2002 12Z RAOBS/WATER VAPOR LOOP SHOW BUILDING RIDGE OVER THE WESTERN GREAT LAKES...WITH DEPARTING TROUGH OVER THE EASTERN LAKES. ONE LINGERING VORT CENTRAL NEAR SAGINAW BAY ROTATING AROUND THE TROUGH. SURFACE ANALYSIS SHOWS A WEAK TROUGH JUST SOUTH OF THE STATE...WITH A WEAK HIGH OVER LAKE HURON. VISIBLE SATELLITE/METARS INDICATE A BAND OF MID CLOUDS FROM SOUTHERN LAKE MICHIGAN INTO OHIO NEAR THE WEAK BOUNDARY...ACC ON SATELLITE AND AS REPORTED BY OBSERVERS AT LAN/MBS/YQG/YZR. COLD POOL CONTINUES TO PULL EAST AS HEIGHTS BUILD WITH THE APPROACHING RIDGE...WITH 12Z RUC INDICATING 500MB/700MB TEMPERATURES CLIMBING 4C/3C RESPECTIVELY. 850-500MB LAPSE RATES STILL UP NEAR 6.5C/KM...DESPITE CAP DEVELOPING NEAR 700MB...WHICH DROPS 700-500MB LAPSE RATES TO 5C/KM. UPSTREAM SOUNDING FROM GRB LOOKS REPRESENTATIVE FOR THIS AFTERNOON OVER THE CWA. MODIFIED FOR T/TD OF 75/52 YIELDS A COUPLE HUNDRED JOULES OF CAPE...NOT MUCH COMPARED TO THE 1500 J/KG FROM A MODIFIED DTX SOUNDING. DESPITE THE SCATTERED NATURE OF THE MID CLOUDS ACROSS THE SOUTHERN CWA...RUC/ETA STILL POINTING TO 700MB RH OVER 70 PERCENT. CU EXPECTED WITH MOISTURE AND STEEP LOW-LEVEL LAPSE RATES...AND IS ALREADY BEGINNING TO DEVELOP. SOME LOW-LEVEL CONVERGENCE ALONG THE WEAK BOUNDARY TO THE SOUTH... WHICH MAY BE A CONCERN FOR THE AFTERNOON. RUC/ETA INDICATE 925MB CONVERGENCE NOSING INTO THE SOUTHERN CWA THIS AFTERNOON. LOCAL ETA-6 AND ETA-XX BOTH PRINT OUT QPF ACROSS THE SOUTH THIS AFTERNOON. TEND TO THINK THIS IS OVERDONE GIVEN THE AMOUNT OF MID-LEVEL WARMING THAT IS ONGOING. WILL HOLD ON TO THE DRY FORECAST FOR TODAY...ALTHOUGH WHILE CONTINUING TO MONITOR THE PRECIP CHANCES. .DTX...NONE. BRAVENDER mi AREA FORECAST DISCUSSION...CORRECTED TIME NATIONAL WEATHER SERVICE STATE COLLEGE 1120 AM EDT TUE JUN 18 2002 UPDATE TO UP POPS FROM I-80 SOUTH AS SHORTWAVE LOOKS TO BE MOVING EAST ACROSS SOUTHERN PA. RUC PROPAGATES FEATURE ACROSS SOUTHERN PA AND BLOWS UP CONVECTION QUITE A BIT THIS AFTERNOON...BUT TS SHOULD BE GARDEN VARIETY AS FCST SOUNDINGS DON'T SUPPORT SEVERE. INCREASED CLOUDS SOUTH OF I-80 AS WELL. KNOCKED DOWN TEMPS A BIT WHERE INCREASED CLOUD COVER. NO CHANGES TO LATER PERIODS. .CTP...NONE. DIRIENZO pa AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY 1000 AM MDT TUE JUN 18 2002 SHORT WAVE/CONVECTION MOVG EAST OF CWFA ATTM. WK SFC TROF EXTENDS N-S ACRS CNTRL DAKOTAS. FORECAST CHALLENGE REMAINS TSTM CHANCES...AND POSSIBILITY OF THEM BCMG SVR. BEST CAPE TDY ACRS SCNTRL ZONES. HOWEVER...FCST RUC SOUNDINGS INDICATE AFTN CIN AOA 50J/KG. WITH MINIMAL UPPER LVL FORCING...EXPECT NO MORE THAN ISOLD TSTMS. LESS CAPPING IN PLACE ACRS REMAINDER OF ZONES...BUT MINIMAL CAPE AND LACK OF FORCING TO INHIBIT WIDESPREAD CONVECTION. HOWEVER...GIVEN AMPLE SHEAR ANY STORMS THAT DO DEVELOP THIS AFTN MAY ROTATE. BEST CHANCES FOR TSTMS REMAIN THIS EVE/TONIGHT GENERALLY ALONG/N OF I-90 AS POTENT SHORT WAVE APPROACHES. HAVE MADE MINOR ADJUSTMENTS TO ZONES MAINLY TO REMOVE MORNING WORDING. .UNR...NONE. JOHNSON sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD, VA 1020 AM EDT TUE JUN 18 2002 WILL CONTINUE WITH THE ISOLATED CHANCES OF SHOWERS/TSTMS OVER THE VA/MD ZONES AS TAIL END OF NRN STREAM SHORTWAVE TROUGH DROPS THROUGH THE REGION. CURRENTLY...THIS SHORTWAVE IS PIVOTING THROUGH OH/PA PER THE LATEST WV/IR STLT LOOPS. WEAK FORCING FROM THIS SHORTWAVE (DPVA/QS CONVERGENCE)...ALONG WITH THE DIURNAL THERMAL EFFECTS (MOUNTAIN/MARINE LAYER STABILITY OR MESO-HIGHS W AND E WITH ASSOCIATED CONVERGENCE IN BTWN) WILL ALLOW THE SURFACE TROUGH TO LIFT BACK N INTO THE VA COASTAL PLAIN. MARGINAL INSTBY AND OVERALL DRY AIRMASS/LOWER INSTBY WILL KEEP CONVECTION ISOLATED OVER VA/MD THIS AFTN...THUS HAVE CONTINUED WITH THE 20% POPS. CAPES IN THIS REGION PER MODIFIED KWAL/KLWX SOUNDINGS ARE EXPECTED TO RANGE BTWN 1000-1500 J/KG. WILL ALSO KEEP SLIGHTLY BETTER CHANCES (30%) OVER NE N CAROLINA... GIVEN INCREASED 850-500 MB LIFT FROM A SRN STREAM VORT LOBE LIFTING INTO THE CAROLINAS (WHICH OF THE MODELS THE RUC APPEARS TO HAVE A BETTER HANDLE ON). INSTBY POTENTIAL OVER THIS REGION WILL ALSO BE A LITTLE HIGHER GIVEN THE MORE LOW-MID LEVEL MSTR AVAILABILITY (K INDICES INTO THE LOWER 30S). MODIFIED KMHX SOUNDING FOR AN 82/67 TEMP/DWPT REGIME YIELDS CAPES NEAR 2000 J/KG AND LI'S AROUND -6C. SEVERE WEATHER CHANCES THOUGH WILL LIMITED BY THE MID/UPPER LEVEL CLOUD SHIELD ALONG THE UPPER JET AXIS. THIS WILL CUT DOWN ON SURFACE BASED HEATING...WHILE LACK OF DRY AIR ALOFT WILL ALSO LIMIT THE MICROBURST POTENTIAL (WBZ HEIGHTS ~11.5 KFT) AS WELL AS MID LEVEL LAPSE RATES (5.5 C/KM OR LESS). MARINE FCST...LITTLE IF ANY CHANGES. .AKQ... MD...NONE. NC...NONE. VA...NONE. HURLEY va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 210 PM EDT TUE JUN 18 2002 SHORT TERM (TNGT-WED): AMS CONTS TO DESTABILIZE BUT SO FAR NOT MUCH HAPPENING UPSTREAM...NEAREST LTG IS OVR SRN PA. SAT PIX SHOW CU FIELD INCRSG INVOF CATSKILLS AND NRN PA...AND THIS IS AREA TO WATCH THRU LATE AFTN FOR ANY CNVTCV DVLPMNT. BOTH ETA/RUC CONT PREV TRENDS WITH INCRSG TT (L50S)...TQ (L20S) AND CAPE (500-1000) BUT K INDICES ARE LWR THAN YDA. 15Z RUC HAS BACKED OFF SOMEWHAT FM ITS ERLR FCSTS BUT STILL SHOWS SCTD SHWRS/TSTMS ACRS CT AND MERR VLYS THRU ERLY EVE. AM GOING TO MAKE FINAL DECISION FOR EVE ACTVTY BASED UPON 18Z RUC...BUT AM PLANNING TO CARRY AT LEAST SOME MNTN OF PCPN ACRS INTERIOR ZNS ERLY. MDLS ARE NOW MORE INSISTENT ON PCPN WED...AND IN FACT POTL FOR CNVTCN IS GREATER THAN TDA ON BOTH AVN/ETA. SOME TIMING DIFFS BTWN MDLS WITH AVN BRINGING IN PCPN DURG MRNG...ETA HOLDG OFF TIL AFTN. ALTHO GRAD IS VIRTUALLY NON-EXISTENT WEAK BNDRY REMAINS DRAPED OVR SRN NEW ENG WHICH SHUD SERVE AS A FOCUS FOR CNVTCN...AS WELL AS OROGRAPHIC LIFT. CAN'T RULE OUT SOME SHWRS ERLY (SPCLY W) PER AVN SO WL BRING CHC POPS IN WED MRNG W AND BY AFTN E. XPCT TO SEE MOST OF ACTVTY FM AFTN INTO EVE WITH POTL FOR ISOLD SVR AS WET BULB ZERO REMAINS 7-8KFT WITH EL 20-25KFT. NO HEADLINES ON MARINE FCST. MID TERM (WED NGT-SAT): PATTN FINALLY QUIETS DOWN AS WEAK SFC BNDRY WASHES OUT AND SFC HI OFF COAST DOMINATES. LL FLO GRDLY TURNS SW BY FRI WHICH WL FINALLY GIVE US THE LONG-AWAITED WARMUP. NXT CDFNT COMING OUT OF GRTLKS FRI AFTN BECOMES PARALLEL TO UPR FLO SAT...SO DECIDED TO HOLD OFF ON ANY MNTN OF PCPN TIL SAT AFTN OR SAT NGT. RESTRICTED POPS TO RUFFLY MASS PIKE NWD WHERE BETTER LL CONV AND UPR SUPPORT PROGGED. LONG TERM (SUN-TUE): STAYING CLOSE TO 00Z/18 OPAVN WHICH KEEPS CLOSED UPR LO FAR ENUF S TO KEEP ITS EFFECTS AWAY FM FA...THERE IS ALSO GOOD AGRMNT AMONG MAJORITY OF MED RANGE MDLS WITH THIS FEATURE. STG UPR RDG CENTERED OVR WV SUN MRNG SLWLY BLDS S BY DAY 7...PUTTING NERN STATES ON TOP OF RDG AND ALLOWING NRN STREAM TO DOMINATE. PLANNING ON CARRYING CHC POPS SUN NGT AS CDFNT EXITS COAST...THEN AGAIN MON NGT/TUE AS SFC LO TRACKS ACRS GRTLKS AND WMFNT BECOMES QSTNRY OVR SRN NEW ENG AS IT BCMS PARALLEL TO UPR FLO. MEX TMPS CLOSE TO ENSEMBLE MEANS BUT CUT BACK A FEW DEGS GIVEN XPCTD CLD CVR. BYD DAY 7...AVN KEEPS BNDRY IN PLACE MEANING AT LEAST DIURNAL CNVTCN LOOKS PROBABLE THRU MUCH OF NXT WEEK...BEFORE FNT BACKDOORS LATE IN WEEK WITH LARGE SFC HI OVR MARITIMES. .BOX... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. JWD ma AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 415 PM EDT TUE JUN 18 2002 12Z RAOBS/LATEST WV LOOP AND RUC ANAL SHOW A RDG OVR THE GRT LKS (12 HR H3 HGT RISES AOA 100M WITH SUBSIDENCE INVRN ARND H8) BTWN A FILLING TROF OVR THE E AND A VIGOROUS SHRTWV TROF MOVG THRU THE PAC NW. THIS SHRTWV ACCOMPANIED BY 100KT H3 JET MAX AND 12 HR H3 HGT FALLS AOA 150M. SFC HI PRES/DRY AIR (12Z PWAT ARND 0.60 INCH AT INL/GRB) UNDER THE UPR RDG BRINGING A TRANQUIL WX DAY TO CWA...WITH DRY SELY TRAJECTORIES NOTED ACRS THE NW GRT LKS OUT OF HI CENTER OVR LK HURON. BUT HIGHER MSTR LURKING TO THE SW...WITH PWATS AOA 1 INCH FM BIS TO MPX. TSRA NOTED IN ADVANCE OF SHRTWVS...THE STRONGEST ONE IN MT AND ANOTHER IN ND...SHOOTING OUT OF MAIN TROF IN THE PAC NW AS THEY INTERACT WITH THIS MOISTER AIR. MAIN FCST CONCERNS THIS PACKAGE ARE TIMING THE ARRIVAL AND DEPARTURE OF CNVCTN ASSOCIATED WITH PAC NW SHRTWV. PRES GRADIENT PROGGED TO SHARPEN TNGT AS ADVANCING SHRTWVS CAUSES LWRG PRES OVR THE NRN PLAINS WHILE MORE TENACIOUS RDG HANGS IN OVR THE NE CONUS UNDER BLDG UPR RDG IN THE LKS IN ADVANCE OF SHRTWVS MOVG IN FM THE W. LEADING SMLR SCALE SHRTWVS PROGGED TO LIFT MORE NE INTO CAN IN RESPONSE TO FALLING HTS FARTHER W AND BLDG RDG IN THE LKS...WITH MODELS INDICATING NO IMPACT FM THESE ADVANCE SHRTWVS ON WX OVR CWA. FCST LLVL WNDS/TRAJECTORIES REMAIN OUT OF THE SSE THRU 12Z WED...SO THINK DRY AIR WL HOLD ITS GROUND TNGT UNDER RISING HGTS. SINCE NO MODEL...EVEN THE MORE AGGRESSIVE ETA AT MOISTENING THE LLVLS...GENERATES QPF IN THE CWA TNGT...HAVE OPTED TO REMOVE MENTION OF PCPN ACRS THE FAR W. BEST CHCS FOR TSRA DVLPMNT WL BE MUCH FARTHER S CLOSER TO H85 WARM FNT IN NE IA/SE MN/SW WI...WHICH WOULD ACT TO INTERCEPT MSTR FLOWING TOWARD CWA. DEBRIS CLD FM UPSTREAM CNVCTN WL IMPACT WI BORDER/WRN ZNS...BUT SKIES WL BE MCLR FARTHER E. ALTHOUGH FLOW OF DRIER AIR WL CONT IN THE LLVLS...INCRSG WNDS WL HOLD TEMPS MUCH HIER THAN LAST NGT MINS. THE IMPACT WL BE GREATEST ACRS THE W...WHERE THE PRES GRADEINT WL BE SHARPER ALL NGT (ETA DEPICTS 45KT WND AS LO AS 2K FT AGL AT IWD OVRNGT) AND PWAT/UPR LVL MSTR INCRSES EARLIER. MOS MINS LOOK RSNBL...BUT WL TEND TO UNDERCUT BY A FEW DEGREES OVR THE E SINCE DWPTS ARE SO LO (37 AT SAW AT 19Z). AVN BRUSHES SRN TIER ZNS WITH REMNANT PCPN FM MCS IT DVLPS ALG WARM FNT TO THE S TNGT...BUT THINK AVN SUFFERING FM USUAL CONVECTIVE FEEDBACK PROBLEM AND TOO STRG WITH SHRTWV/H4-2 DVGC IT PROGS TO MOVE ACRS NRN WI/SRN TIER CWA ON WED MRNG. BUT DEBRIS CLD FM CNVCTN WL BE MOST PREVALENT ACRS THE S AND W. ALTHOUGH ETA/NGM GENERATE QPF OVR THE WRN HALF OF CWA IN THE AFTN...IN THE ABSENCE OF ANY BNDRY UNDER ACYC H85 FLOW/SUPPRESSED LK BREEZES...RISING H5 HGTS/TEMPS (TO -8C AT IWD BY 18Z) AND WITH MORE OF A DUE S SFC FLOW...THINK DAY WL BE DRY PER CNDN MODEL FCST...SO POPS UNDER GUIDANCE FCST. ETA AS USUAL APPEARS TOO AGGRESSIVE AT PUSHING SFC DWPT TOWARD 67 AT IWD BY AFTN...ITS MODIFIED SDNG FOR TD OF 60 PER AVN GUIDANCE AT 18Z SHOWS CAPE/CIN DCRSG FM 670/-30 J/KG TO 150/-30 J/KG EVEN FOR TEMP UP TO 80. DEBRIS CLD FM CNVCTN TO THE SW WL LIMIT INSOLATION A BIT AND HOLD DOWN MAX TEMP/CAPE AS WELL. AVN GUIDANCE FOR MAX TEMPS APPEARS TOO INFLUENCED BY ITS FCST MRNG CNVCTN/THICKER DEBRIS CLD. FWC GUIDANCE LOOKS MORE REALISTIC. XPCT BREEZY CONDITIONS AS INSOLATION MIXES STRG GRADIENT FLOW TO THE SFC. TMRW NGT...MAIN SHRTWV LIFTS NE INTO ONTARIO ON WRN FLANK OF UPR RDG AXIS OVR ERN LKS...DRAGGING SFC FNT INTO THE WRN ZNS BY 12Z. ALL BUT CNDN MODEL GENERATE SOME QPF OVR CWA WED NGT...ALBEIT LGT. THINK NOCTURNAL STRENGTHENING OF LLJ...FCST PWATS OVR 1.5 INCH...AND ARRIVAL OF SFC BNDRY WARRANTS INCLUSION OF POPS EVERYWHERE...HIEST OVR THE FAR W CLOSEST TO BNDRY. BUT LIFTING OF SHRTWV/DEEPEST MSTR INTO CAN WITH NEGLIGIBLE FALL OF H5 HGT/TEMP OVR CWA WOULD SUG CHCY POPS AND NO HIER. SPC OUTLOOK HAS WRN ZNS IN SLGT RISK AREA...BUT LINGERING HI MID LVL TEMPS IN ABSENCE OF STRG DYNAMICS A MAJOR LIMITING FACTOR DESPITE STRG H85 WNDS. TGT GRADIENT SWLY FLOW/MIXING AND HIER PWAT INDICATE MIN TEMPS CLOSER TO HIER NGM/ETA MOS GUIDANCE IN ORDER. WEAKENING SFC FNT WITH LOSS OF UPR DYNAMICS PROGGED TO SLOWLY LIMP ACRS CWA ON THU AS WSWLY UPR FLOW BCMS MORE PARALLEL TO BNDRY ON WRN PERIPHERY OF RDG. AVN THE SLOWEST MODEL TO PUSH DRYING INTO THE W ON THU WITH WHAT APPEARS AS CONVECTIVE FEEDBACK SHRTWV RIDES NE ALG BNDRY AND INVIGORATES QPF ALG BNDRY. WL TEND TOWARD THE MORE AGGRESSIVE DRYING OF THE ETA GIVEN THE AVN'S PROBLEM WITH CONVECTIVE FEEDBACK...THE CNDN MODEL APPEARS RSNBL AS A COMPROMISE CLOSER TO THE ETA. WL DRY OUT THE W THU AFTN...BUT KEEP POPS ALL THU NGT ACRS THE E. THEN DRY EVERYWHERE ON FRI WITH SFC HI FCST TO BLD OVR THE NW GRT LKS BEHIND DISSOLVING FNT. EXTENDED MODELS CONT TO ADVERTISE TREND TOWARD MORE SUMMERLIKE PATTERN WITH WELL ABV NORMAL H5 HGTS FCST ACRS ESPECIALLY ERN NAMERICA. WITH CWA ON SRN FLANK OF MAIN BRANCH OF WESTERLIES ACRS CAN AND TO N OF MEAN RDG/WARMEST AIR IN THE CNTRL CONUS...SOME ACTIVE TSRA WX PSBL. MODELS REMAIN IN GOOD AGREEMENT ON TIMING OF SHRTWV PASSING TO N ON SAT...SO FCST SHRA/TSRA CHCS ON THAT DAY LOOKS ON TARGET. ECMWF/UKMET LOOK MORE AGGRESSIVE WITH DRYING/BLDG HI PRES OVR THE NW LKS ON SUN...BUT OPERATIONAL MRF/CNDN DEPICT A BNDRY IN VCNTY ALL DAY WITH SLOWER SHRTWV PROGRESSION. MRF/CNDN ENSEMBLES OFFER LTL RESOLUTION... SO WL MAINTAIN GOING FCST SHRA/TSRA CHCS ON SUN. OPERATIONAL MRF KEEPS BNDRY ARND ON MON... BUT SINCE MAJORITY OF MRF/CNDN ENSEMBLE MEMBERS AND ECMWF HINT AT DRYING AND COOLING ON MON...WL CONT DRY FCST THEN. OUTLOOK FOR TUE IS UNCLEAR...BUT WITH CWA ON SRN FLANK OF ACTIVE UPR JET TO THE N... WL GO WITH CHC SHRA/TSRA THEN. TEMPS THRU EXTENDED PD GENERALLY AOA MOS FCST...XCPT FOR MON WHEN TEMPS GENERALLY BLO MOS GUIDANCE. COORDINATED WITH APX. .MQT...NONE. KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 300 PM CDT TUE JUN 18 2002 FCST CHALLENGE RMNS CONVECTION CHCS/COVERAGE AND INTENSITY TNGT... MAINLY THIS EVENING...THEN HOW FAR S CDFNT WILL PUSH LATE WED NGT/THU. MODELS WERE FAIRLY CLOSE WITH FNTL PSN INTO WED AFTN AND A BLEND WAS USED. AVN AND ETA CONTD THEIR RESPECTIVE TRENDS W/FRONT ON THU. AVN CONTD TO PUSH IT S THRU FCST AREA WHILE ETA MOVED IT TWD SRN ZONES THEN STALLED IT OR EVEN MOVED IT N A LTL. SINCE FNT WL BE MOVG S INTO RISING 500 MB HGTS...IN FACT ETA/AVN BOTH BUILD 5940 M HGT INTO SERN NEBR BY 00Z FRI...WL LEAN A LTL MORE TWD ETA THU. SHORT TERM...CONVECTIVE SITUATION CONTS THE MAIN CHALLENGE AND THE QUESTION RMNS WHETHER CAP WL BREAK IN FCST AREA. FCST SOUNDING FM ETA BUFKIT SHOWED CAP ERODING AT OFK AND OMA 19Z-21Z. WARMING MID LVL TEMPS THEN BROUGHT CONVECTIVE INHIBITION BACK TO OMA BY 00Z WHILE MOISTURE INCREASED FAST ENOUGH WITH WARMING TEMPS TO KEEP LTL OR NO CIN AT OFK. BASED ON THIS ALONE WOULD SUGGEST HIGHER POPS NRN ZONES. HOWEVER...LATEST LAPS SHOWED A MUCH HIGHER CIN AT 19Z THAN 12Z ETA OR EVEN THE LATEST RUC FCST. AND LATEST RUC DIDN'T LOWER CIN BLO 40 J/KG UNTIL 00Z-03Z TIME PD BUT THEN DVLPD ITS PCPN N OF FCST AREA. WILL STILL RUN THE HIGHEST POPS NRN ZONES BECAUSE OF THESE TRENDS...BUT WL NOT GO IN LIKELY CAT OR MENTION SVR UNLESS CONVECTION WOULD DVLP BFR ZONE ISSUANCE TIME. ALTHO IF STORMS DO OCCUR IN FCST AREA THIS EVENING...ENOUGH SHEAR EXISTS TO ALLOW FOR SVR STORMS. CAP IS FCST TO RMN AT LNK AND THEN EVEN BUILDS TWD 04Z SO WL LEAVE SERN NEBR ZONES DRY. PREV FCST LOWS LOOK GOOD. WINDY AND WARM/HOT CONDS LOOK LIKELY ON WED. ETA/NGM 850 MB TEMPS WOULD EVEN SUPPORT UPR 90S AT LNK AND EVEN OFK IF FNT WOULD HOLD OFF. AVN RMNS THE COOLER MODEL BUT EVEN IT SUGGESTS LOWER 90S SW. ACTUALLY ETA MOS LOOKS REASONABLE AND WL ADJ FCST UPWARD TO THESE NUMBERS. FEEL THERE WILL BE NO CONVECTION AND LTL CLOUDS AT LEAST FM MID MORNING THRU MID AFTN SO MIXING DOWN 850 MB WINDS SHOULD POSE NO PRBLM. WL MENTION WINDY MOST ZONES...SPCLY SINCE WINDS HAVE EVEN REACHED THAT CRITERIA TDA. WL COUNT ON FRONT REACHING NEAR OFK BY LATE AFTN TO CONT AFTN TSTMS CHCS NWRN ZONES. WL LEAVE ROFA DRY. WITH FRONT PUSHING CLOSE TO OMA WED NGT...AIDED BY CONVECTIVE OUTFLOW...FEEL A BOOST IN POPS IS WARRANTED. IN FACT WL GO LIKELY CATEGORY NWRN ZONES. EVEN THOUGH FRONT MAY NOT MAKE IT INTO SERN NEBR...WL KEEP SOME MENTION OF STORMS THERE AS A FEW COULD BE GENERATED BY OUTFLOW AHD OF FNT. THEN ON THU LEANING MORE TWD ETA WOULD HOLD THE FRONT NEAR OMAHA. THUS WL GO MORE WITH ETA MOS S OF THE FRONT WITH ONLY A SLGT CHC OF CONVECTION...MAINLY JUST IN CASE FNT DROPS FTHR S THAT EXPECTED. ETA/NGM AND AVN MOS FAIRLY CLOSE NRN ZONES AND WL RAISE TEMPS A LTL TWD THOSE NUMBERS FAR N. BOTH ETA EXTENSION AND AVN LIFT FNT MOSTLY N OF FCST AREA BY FRI AFTN. THUS WL ONLY MENTION MORNING TSTMS N AND RAISE TEMPS A LTL ALL AREAS. DAYS 4-7...ON SAT REMOVED SLGT CHC TSTMS AND RAISED TEMPS ALL ZONES AS BOTH ECMWF AND AVN FCST UPR RIDGING W/LTL CHC OF PCPN. BOTH MODELS ALSO SUGGESTED SOME WK WAVE PSBLY KNOCKING DOWN UPR HGTS A LTL SUN...ALTHO AVN WAS FTHR N...SO KEPT SMALL POPS IN WITH SLIGHTLY COOLER TEMPS. MODELS DIVERGED A LTL MON WITH ECMWF HOTTER/DRIER THAN AVN WHICH BROUGHT ANOTHER WK FNT THRU. ENOUGH UNCERTAINTY THEN TO CHANGE PREV FCST SO LEFT NUMBERS PRETTY MUCH ALONE AND CONTD THESE CONDITIONS INTO TUE. .OMA...NONE. CHERMOK ne AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY 245 PM MDT TUE JUN 18 2002 FORECAST CHALLENGE REMAINS TSTM CHANCES TONIGHT...AND POSSIBILITY OF SVR WX. UPR LOW MOVG EWD ACRS THE PAC NW ATTM...WITH WATER VAPOR DEPICTING JET STREAK ENTERING NRN ROCKIES. BROAD TROF ACRS DAKOTAS WITH SOME CONVECTIVELY INDUCED WINDS ACRS THE SD PLAINS FROM EARLY MRNG TSTMS. LATEST RUC ANALYSIS DEPICTS IMPRESSIVE CAP GENERALLY S OF I-90 OVR WRN SD...AND EXPECT LITTLE CHANCE OF THIS BREAKING THIS EVE. APRCH JET STREAK SPARKING MAINLY ELEVATED CONVECTION NWRN ZONES...BUT DO EXPECT THIS TO BECOME MORE SURFACE BASED THIS AFTN/EVE AS CAP IS RAPIDLY ERODING IN THIS REGION. APPROACHING SHORT WAVE LATER THIS EVE WILL ENHANCE CONVECTION THIS AREA...AND STRONG SHEAR/HI LCL'S SUPPORT SUPERCELLS WITH LARGE HAIL AND DOWNBURST WINDS. IN A NUTSHELL...EXPECT MOST ACTIVITY/POTENTIAL SUPERCELLS NORTH OF I-90 THIS EVE. SOME CONVECTION MAY FIRE LATER TONIGHT FURTHER SOUTH AS STRONG CDFNT SWEEPS ACRS REGION...ALLOWING CAP TO BE OVERCOME. PCPN SHOULD COME TO AN END DURG THE MRNG AS CDFNT/INSTABILITY MOV E. WILL HAVE TO PUT UP WITH BRIEF PERIOD OF WINDY CONDS IN THE AM AS NARROW BAND OF 5-7MB PRES RISES SPREAD ACRS AREA BEHIND CDFNT...ALTHOUGH OPPOSING GEOSTROPHIC/ISALLOBARIC COMPONENTS SHOULD KEEP BLO HIGHLIGHT CRITERIA. OTHER THAN A FEW -SHRA WED AHEAD OF UPPER TROF...LOOKS MOSTLY DRY THU WITH SUBSIDENCE BEHIND UPPER TROF. NEXT CHANCE FOR PCPN LATE THU NIGHT THRU FRI AS SW FLOW RETURNS AND AVN DEPICTS SEVERAL EMBEDDED SHORT WAVES. SFC LOW DVLPG ACRS SD ON FRI COULD BRING MORE SVR WX TO AREA...AND BEARS WATCHING. EXTENDED...UNSETTLED PATTERN THRU SUN...THEN DRY UPPER RIDGE BUILDS RETURNING REGION TO HOT AND DRY WEATHER FIRST PART OF NEXT WEEK. .UNR...NONE. JOHNSON sd