AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 159 PM EDT MON MAY 26 2003 .DAY 1-3 THOUGHTS... COLD 500MB LOW REMAINS ANCHORED OVER SERN ONTARIO THIS AFTERNOON, WITH ANOTHER NICE WAVE NOW OVER MO PROPAGATING TOWARDS THE LMK FA. WAVE NOW MOVING THRU RELATIVE MINIMUM IN PWS, PER 15Z RUC, BUT THEN COULD ENTER AREA OF SLIGHTLY HIGHER MOISTURE OVER LMK FA THIS EVENING. WITHIN A REGION OF HIGHER LAPSE RATES POLEWARD OF THIS WAVE, GFS AND NOW THE ETA PRODUCE SOME LIGHT QPF IN VICINITY OF FA. WILL HAVE TO REFLECT ON THIS SOME MORE, BUT MAY CONSIDER SOME SCHC POPS FOR NRN KY/SRN IND THIS EVE. ASSUMING WE CLEAR OUT SOMEWHAT TONIGHT AND WITH PBL MOISTURE REMAINING, SCT FG MAY FORM AGAIN AFTER MIDNIGHT. THE GUIDANCE (PARTICULARLY NGMMOS) IS SUGGESTING BR/FG WHILE RUC VISIB FORECAST FOR 12Z/TUE KEEPS THE FG WELL E OF THE FA. SINCE PBL IS WELL MIXED TODAY, THE NEAR SURFACE MOIST LAYER FORECAST IN THE ETA FOR 8-12Z/TUE IS MUCH SHALLOWER THAN THIS MORNING. SOME DEW ON THE GRASS AND CARS A GOOD BET TOMORROW MORNING, BUT FG POTENTIAL LOOKS THINNER THAN THIS MORNING. HOWEVER, WILL BOW TO GUIDANCE AND INCLUDE PATCHY LATE NIGHT FOG WORDING. THEN AS THIS WAVE PASSES QUICKLY BY EARLY TUE, MAIN 500MB LOW WOBBLES SWWD TOWARDS LMK FA. LAPSE RATES REMAIN HIGH, ESPECIALLY CLOSER TO LOW CENTER OVER NERN 1/2 OF FA, AND PWS FCST TO BE JUST ABOVE SEASONAL NORMALS. HOWEVER, OVER PAST COUPLE MODEL CYCLES, TRENDS HAS BEEN TO DISPLACE BEST LIFT NEWD FROM LMK FA. OVERALL THINK LOW CHC SHRA NEAR KLEX IS WISE, BUT MAY THROTTLE BACK TO SCHC AROUND KSDF/SRN IND. ALSO, BEST WINDOW FOR PCPN LOOKS TO BE IN THE AFTERNOON AND EARLY EVENING, WHILE INTO THE NIGHTTIME HOURS GENERAL SUBSIDENT PTTN TAKES OVER AS MID-LEVEL TROF SWINGS EWD, ENDING PCPN CHCS. AS RIDGE BUILDS OVER ROCKIES, BOTH GFS AND ETA FCST YET ANOTHER FAIRLY STG WAVE TO DROP SWD INTO LMK FA WED EVE. 12Z GFS MOS POPS ARE QUITE HIGH (80-90%). TRACING THIS WAVE BACK TO ITS ORIGINS REVEALS WHY: GFS IS FORECASTING AN MCS TO DEVELOP OVER THE PLAINS OF ERN MT TONIGHT, WHICH THEN GENERATES A STG MCV FEATURE. THIS MCV THEN GETS INTEGRATED INTO THE NWLY FLOW AND ADDS TO THE STRENGTH OF THE WAVE AS IT APPROACHES THE LMK FA. SINCE GFS TENDS TO INCORRECTLY CREATE THESE ANOMALOUS VORTICITY MAXIMA ASSOC WITH CONVECTIVE SYSTEMS, WILL TAKE A MORE CAUTIOUS APPROACH. ETA FCSTING ~0.1-0.25" QPF AREAWIDE WED NIGHT, SO WILL RAISE POPS TO HIGH CHC. WILL BE INTERESTING TO SEE HOW THIS PLAYS OUT. PER THE GFS BUFKIT DATA, THERE COULD BE SOME LOW CLOUDS THU MORNING BEHIND THIS PCPN, BUT THINK OVERALL PCPN CHCS ON THU LOOK SOMEWHAT MINIMAL, EXCEPT MAYBE IN THE ERN ZONES. .EXTENDED NOTES... ANOTHER SYSTEM FORECAST TO DROP DOWN IN NWLY FLOW ALOFT FOR SAT. THIS ONE HAS SOMEWHAT BETTER SFC-BASED INSTABILITY TO WORK WITH, PER 12Z GFS, THEREFORE WILL KEEP CHC TSRA FOR SAT, BUT REMOVE FOR SUN. LATEST MEDIUM RANGE ENSEMBLE MEANS SUGGEST ERN NOAM TROF WILL REASSERT ITSELF BY SUN, WITH SIG NEGATIVE 500MB HEIGHT ANOMALY DEVELOPING OVER GREAT LAKES. THEREFORE WILL TREND TOWARDS THE NEW COOLER GUIDANCE. .LMK...NONE. XXV ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 955 AM EDT MON MAY 26 2003 WILL ALLOW DENSE FOG ADVISORY TO EXPIRE AT 10AM, AS AREA OBSERVATIONS SHOW SFC VISIB RISING AOA 1SM IN MOST LOCATIONS. STILL SOME ISOLATED SPOTS WHERE FG MAY PERSIST OVER THE NEXT HOUR OR SO. OTHERWISE, PER LATEST RUC THERE MAY BE A PERIOD OF M/SUNNY CONDITIONS AFTER FOG/LOW CLOUDS LIFT, THEN A SCT-BKN LAYER DEVELOPS AROUND 5KFT DURING THE AFTERNOON. RESPECTABLE 500MB WAVE NOW JUST N OF KMCI, WILL TRANSLATE TOWARDS LMK FA LATE THIS EVENING. SOME WEAK 250MB DIVERGENCE AHEAD OF THIS FEATURE, BUT DISTURBANCE IF PROPAGATING THRU AN REGION OF RELATIVE MINIMUM PWS, PER 12Z RAOBS. ALSO ATTM THERE IS NO PCPN OF NOTE ASSOC WITH THIS WAVE OVER MO/IA. HOWEVER, INTO THE EARLY EVENING, WAVE DOES ENCOUNTER SLIGHTLY BETTER ATMOS MOISTURE OVER KY/IN, PER 12Z RUC, AND LAPSE RATES IN MID-LEVELS CERTAINLY INCR AS WAVE MOVES NEARBY. FOR NOW WILL KEEP TODAY/TONIGHT DRY, BUT WILL KEEP AN EYE ON UPSTREAM RADARS FOR SOME ISO -SHRA. .LMK...NONE. XXV ky AREA FORECAST DISCUSSION..UPDATED SHORT TERM.. NATIONAL WEATHER SERVICE TAUNTON MA 1020 PM EDT MON MAY 26 2003 RDR SHWG ORGANIZED PCPN AREA EXITING FA BUT SFC OBS REPORTING LINGERING RAIN AND DRIZZLE ACRS THE CWA. HAVE ADDED PATCHY FOG WITH LOCALLY DENSE IN MOST ZNS. REST OF EARLIER ZNS PKG ON TARGET. MARINE...DROPPED SCA FOR 'GANSETT BAY. ....EARLIER.... PUBLIC SHORT TERM: R+ TAPERING TO L-/FOG FM SW TO NE THIS EVENING BEGINNING 22Z-00Z BDL/PVD AND REACHING MHT-BOS-PVC 04Z. 18Z RUC AND 18Z ETA SUPPORT THIS MUCH HIGHER THAN GUIDANCE LEFTOVR MEAS POP FOR THE 00Z-12Z TIME FRAME. ADDITIONAL SUPPORT IS LOW LVL WAA PATTERN COMBINED WITH MODEL FCSTG TOO WEAK AN ELY GRADIENT IN THE NEAR NRN SEMICIRCLE OF THE SFC LOW WITH 28-38KT WINDS COMMON FROM ALS TO BUZ NOW. SO WHILE IT DRIES OUT ALOFT..ABV 7H THIS EVENING SHUTTING OFF R+...ITS CONCEIVABLE L+ MAY BE OCCURRING THRU 04Z BOS-PYM-HYA. GUIDANCE TEMPS OK AS INCREASING NE WIND ADVECTS COLD MARITIME LAYER SWWD THIS EVE. TUE: CUT MOS TEMPS AOB COLDEST AVBL 12Z GUIDANCE MARINE: COORD WITH OPC ON GALE GUSTS. ETA/RUC INITIALIZED A BIT TOO WEAK AND WE'RE SEEING A 1009 LOW JUST SE OF 44025. EXTRAPOLATE THE GRADIENT AND WE RCV A WDSPRD SCA SITN THIS EVE. GALE GUSTS ENTERED. SLIGHT CHC TSTM SE PTN OF CW BUT NOT IN FCST. STP RFALL: MANY REPS OF 1+ NOW IN RI AND N CT. 3.22 AT FOK! .LONGER TERM...(TUESDAY NIGHT THROUGH MONDAY) BROKEN RECORD FORECAST FORTHCOMING WITH ABUNDANT CLOUDS AND A CHANCE OF SHOWERS EVERY 12-18 HOURS OR SO. THE CULPRIT IS A PERSISTENT UPPER LEVEL LOW WHICH SHOULD KEEP A SERIES OF SHORTWAVES HEADED OUR WAY THROUGH THE UPCOMING WEEK. IN ADDITION TO THE SHORTWAVES...LOW PRESSURES MOVING NORTHEAST FROM THE MID ATLANTIC COAST WILL ALSO INCREASE OUR CHANCES FOR RAIN THIS WEEK. OVERALL THIS PATTERN LOOKS MORE LIKE LATE MARCH THAN LATE MAY. HAVE LEANED A BIT MORE TOWARD CURRENT HPC GUIDANCE FOR TIMING OF SYSTEMS DURING THE LATTER HALF OF THIS WEEK. MEX GUIDANCE NUMBERS LOOK REASONABLE...SO I DO NOT EXPECT TO STRAY TOO FAR. MARINE WISE...IT LOOKS PRETTY QUIET THROUGH NEXT MONDAY AS FAR AS SEAS AND WINDS ARE CONCERNED. .BOX... CT...NONE. MA...NONE. RI...NONE. NH...NONE. MARINE...SCA ALL WATERS...EXCEPT BOS HARBOR AND 'GANSETT BAY. $$ SHORT TERM...DRAG LONG TERM...BELK ma AREA FORECAST DISCUSSION..UPDATED SHORT TERM.. NATIONAL WEATHER SERVICE TAUNTON MA 418 PM EDT MON MAY 26 2003 PUBLIC SHORT TERM: R+ TAPERING TO L-/FOG FM SW TO NE THIS EVENING BEGINNING 22Z-00Z BDL/PVD AND REACHING MHT-BOS-PVC 04Z. 18Z RUC AND 18Z ETA SUPPORT THIS MUCH HIGHER THAN GUIDANCE LEFTOVR MEAS POP FOR THE 00Z-12Z TIME FRAME. ADDITIONAL SUPPORT IS LOW LVL WAA PATTERN COMBINED WITH MODEL FCSTG TOO WEAK AN ELY GRADIENT IN THE NEAR NRN SEMICIRCLE OF THE SFC LOW WITH 28-38KT WINDS COMMON FROM ALS TO BUZ NOW. SO WHILE IT DRIES OUT ALOFT..ABV 7H THIS EVENING SHUTTING OFF R+...ITS CONCEIVABLE L+ MAY BE OCCURRING THRU 04Z BOS-PYM-HYA. GUIDANCE TEMPS OK AS INCREASING NE WIND ADVECTS COLD MARITIME LAYER SWWD THIS EVE. TUE: CUT MOS TEMPS AOB COLDEST AVBL 12Z GUIDANCE MARINE: COORD WITH OPC ON GALE GUSTS. ETA/RUC INITIALIZED A BIT TOO WEAK AND WE'RE SEEING A 1009 LOW JUST SE OF 44025. EXTRAPOLATE THE GRADIENT AND WE RCV A WDSPRD SCA SITN THIS EVE. GALE GUSTS ENTERED. SLIGHT CHC TSTM SE PTN OF CW BUT NOT IN FCST. STP RFALL: MANY REPS OF 1+ NOW IN RI AND N CT. 3.22 AT FOK! .LONGER TERM...(TUESDAY NIGHT THROUGH MONDAY) BROKEN RECORD FORECAST FORTHCOMING WITH ABUNDANT CLOUDS AND A CHANCE OF SHOWERS EVERY 12-18 HOURS OR SO. THE CULPRIT IS A PERSISTENT UPPER LEVEL LOW WHICH SHOULD KEEP A SERIES OF SHORTWAVES HEADED OUR WAY THROUGH THE UPCOMING WEEK. IN ADDITION TO THE SHORTWAVES...LOW PRESSURES MOVING NORTHEAST FROM THE MID ATLANTIC COAST WILL ALSO INCREASE OUR CHANCES FOR RAIN THIS WEEK. OVERALL THIS PATTERN LOOKS MORE LIKE LATE MARCH THAN LATE MAY. HAVE LEANED A BIT MORE TOWARD CURRENT HPC GUIDANCE FOR TIMING OF SYSTEMS DURING THE LATTER HALF OF THIS WEEK. MEX GUIDANCE NUMBERS LOOK REASONABLE...SO I DO NOT EXPECT TO STRAY TOO FAR. MARINE WISE...IT LOOKS PRETTY QUIET THROUGH NEXT MONDAY AS FAR AS SEAS AND WINDS ARE CONCERNED. .BOX... CT...NONE. MA...NONE. RI...NONE. NH...NONE. MARINE...SCA ALL WATERS EITHER DUE TO ROUGH SEAS AND/OR INCREASING WINDS...EXCEPT NOT BOS HARBOR (HOWEVER SEAS AROUND 5 FT AT THE HARBOR ENTRANCE). $$ SHORT TERM...DRAG LONG TERM...BELK ma SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1051 AM EDT MON MAY 26 2003 PERSISTENT UPPER LEVEL LOW CAN BE SEEN JUST EAST OF GEORGIAN BAY ON ALL THE SATELLITE DATA. THE 12Z UPPER AIR OBS...CURRENT SURFACE OBS AND THE LATEST VISIBLE LOOP INDICATES THAT PLENTY OF MOISTURE IN THE LOW LEVELS CONTINUE TO WRAP AROUND THE UPPER LOW AND INTO SOUTHEAST MICHIGAN. WITH THE 12Z KDTX SOUNDING SHOWING NEAR SATURATED CONDITIONS IN THE 750-900MB LAYER...DIURNAL CU SHOULD BE QUITE WIDESPREAD THIS AFTERNOON. THE LATEST VISIBLE IMAGES ARE BEGINNING TO SHOW THIS MORNINGS BREAKS QUICKLY FILLING IN WITH CU. FOR THE MOST PART...AFTERNOON CU FIELD WILL REMAIN BROKEN. DIURNAL MIXING SHOULD HOWEVER BEGIN TO ALLOW MORE SUNSHINE BY LATE AFTERNOON. WITH THIS SAID AND WITH THE LATEST VISIBLE IMAGE STILL SHOWING CONSIDERABLY BREAKS IN THE CLOUDS...I WILL CONTINUE WITH AN OPTIMISTIC PARTLY SUNNY FORECAST. EXPECT VFR CONDITIONS WITH CU FIELD THIS AFTERNOON. THE EXCEPTION WILL BE ACROSS THE SAGINAW VALLEY AND THUMB WHERE A STRATUS DECK OFF OF LAKE HURON SHOULD MAINTAIN LOCALLY LOWER CIGS FOR THE NEXT 2 TO 3 HOURS...POSSIBLY LONGER OVER THE THUMB. UPDATED ZFPDTX AND GRIDDED FORECAST HAVE ALREADY BEEN ISSUED. I ADDED A MENTION OF A SLIGHT CHANCE OF AFTERNOON SHOWERS ACROSS THE ENTIRE FORECAST AREA GIVEN THE LATEST RUC AND MESO ETA SOUNDINGS SHOWING STEEP SFC TO 850MB LAPSE RATES WITH CAPE AROUND 100 J/KG BY LATE AFTERNOON. I ALSO LOWERED TEMPS ACROSS THE THUMB BASED ON CURRENT READINGS. PERSISTENT LAKE STRATUS AND NORTHEAST WINDS OFF LAKE HURON WILL HOLD TEMPS DOWN SEVERAL DEGREES FROM LOCATIONS FARTHER INLAND. CONSIDINE ..............PREVIOUSLY ISSUED AREA FORECAST DISCUSSION........... ...PERIODIC SHRA/TSRA CHCS BECOMING MAIN CHALLENGE... A VERY STAGNANT WX PATTERN WILL BE SHIFTING INTO AN ACTIVE ONE THIS WEEK AND MAYBE BACK TO STAGNATION NEXT WEEKEND? 00Z UAA SHOWED UPPER LOW NOW A FAR DISTANCE EAST OF CWFA...BUT MODELS STILL WOBBLE IT BACK THIS WAY FOR TUE/WED. THEREAFTER A SERIES OF DISTURBANCES RACE INTO THE AREA ON NW FLOW FROM THE NRN PACIFIC...THE FIRST OF WHICH IS NOW PROGGED INTO THE AREA WED NIGHT/THU AM...A BIT FASTER. THIS STILL KICKS THE CURRENT UPPER LOW OUT OF AREA...BUT REALLY DOESN/T CHANGE THE BLOCKING PATTERN APPRECIABLY...SAVE A FEW DAYS LATE THIS WEEK. RIDGE REMAINS ANCHORED OVER WRN CONUS AND TROFFING CONTINUES OFF THE WEST COAST. WILL CHANGE VERY LITTLE IN THIS FORECAST. FOR THE FIRST FIVE DAYS. NOT MUCH HAS CHANGED IN MODEL PROGS SO ONLY MINOR TWEAKS NEEDED. THEREAFTER...THE BUSINESS OF THE BLOCKING PATTERN MORE OR LESS HOLDING BECOMES AN ISSUE. AFTER SVRL NW FLOW WAVES RACE THRU AREA...GFS NOW DROPS A BIG CHUNK OF COOL AIR DOWN FROM CANADA AS RATHER DEEP UPPER LOW DEVELOPS OVER THE LAKES REGION NEXT WEEKEND INTO EARLY NEXT WEEK. CMC AND UKMET SUPPORT THIS GENERAL IDEA...BUT ARE NOT QUITE AS BULLISH WITH DROPPING HGHTS THAT FAR SOUTH INTO THE REGION. GIVEN THESE ARE DAYS 6/7...NOT WILLING TO BITE HOOK/LINE/SINKER...BUT WILL TREND SUNDAY COOLER. THIS WOULD BE A RATHER UNFORTUNATE DVLPMNT IF THINGS SHAPE UP IN THIS GENERAL WAY...EXTENDING AN ALREADY COOL/ DAMP SPRING INTO JUNE. AGAIN...NOT MUCH CHANGE TO GOING FORECAST W/ TEMPS PUSHING 70 TODAY THEN DROPPING BACK 5 OR SO DEGREES ON TUESDAY WITH UPPER LOW WOBBLE THEN EDGING BACK UP TO 70 THU AND INTO THE 70-75 RANGE FRI/SAT. BEST SHOTS AT PRECIP WILL BE SOME SHRAS ON TUE W/ UPPER LOW...SCT SHRAS AND TSRAS WED NIGHT/THU AND FRI NIGHT/SAT WITH NW FLOW WAVES. WE/LL SEE HOW THINGS SHAPE UP AFTER THAT. .DTX...NONE. $$ GURNEY EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 307 PM EDT MON MAY 26 2003 CURRENT VIS SAT INDCG PLENTY OF SC ACRS GRT LKS AND OH VALLEY THIS AFTN. UPR LO OVER SOUTHERN ONTARIO CONTINUING TO SPIN WITH SOME SHRA/TSRA NOTED TO NORTH AND EAST OF LO. 18Z RUC INDCG LARGE AREA OF MID LVL NVA ACRS FCST AREA. UNSETTLED PATTERN TO CONTINUE FOR GOOD PART OF WEEK...AND FOCUSING ON CHCS FOR RAIN IS THE BIG CHALLENGE FOR FCST PACKAGE. GFS/ETA IN GOOD AGREEMENT THRU 36 HRS IN SLOWING RETROGRADING UPR LO BACK TO SOUTH AND WEST. BOTH MODELS TRACKING UPR LO INTO EASTERN OH BY TUES EVENING...WHICH IS FURTHER EAST THAN PREVIOUS RUNS INDICATED. HOWEVER...THIS POSITION WILL STILL BE CLOSE ENOUGH TO GENERATE SCT PCPN TUES. AM KEEPING FCST AREA DRY TONIGHT...AS S/WV ENERGY ASSOCD WITH UPR LO SPLITS FCST AREA AND KEEPS REGION IN NVA POCKET OVERNIGHT. MODEL SOUNDINGS INDCG LO LVL SUBSIDENCE...WHICH SHOULD ALLOW SC TO THIN SOMEWHAT. WITH PLENTY OF LO LVL MOISTURE HANGING OVERNIGHT...COULD AGAIN SEE SOME PATCHY FG DVLP TOWARDS MORNING...ESPECIALLY IN THE CREEK/RIVER VALLEYS. NEXT VORT LOBE WILL TRACK DOWN AROUND BACK SIDE OF UPR LO TUES AND INTO EASTERN OH BY 00Z WED. THIS WILL KICK OFF SCT SHRA DURING THE AFTN. CANNOT RULE OUT AN ISOLD TSTM AS WEAK CAPES/LI VALUES NOTED ACRS REGION. WILL LINGER LO CHC POPS INTO EVENING...ENDING PCPN FROM WEST TO EAST AROUND MIDNITE. SHOULD SEE A GENERAL THINNING IN CLDS ACRS WESTERN FCST AREA OVERNIGHT TUES AS LO LVL SUBSIDENCE WORKS IN AND UPR LO SHIFTS EAST INTO WESTERN PA. CMH/PMH AREAS LIKELY TO SEE CLOUDS LINGER LONGER AND HAVE LEFT MSTLY CLDY SKIES HERE. BRIEF BREAK WED AS SFC RIDGE SHIFTS INTO REGION. HOT ON ITS HEELS IS A FRNTL BNDRY WITH A DVLPG WAVE WHICH WILL BE OUR WX MAKER FOR WED NITE/THURS. BOTH MODELS HAVE SPED UP TIMING OF SYSTEM...WITH ETA TRYING TO BRING PCPN INTO WESTERN COUNTIES LATE WED AFTN. LIKE THE SLOWER GFS TIMING...WITH SHRA/TSTMS DVLPG WED EVENING IN THE WEST AND TOWARDS MIDNITE ACRS EASTERN COUNTIES. HAVE BUMPED UP TO 50 POPS BUT EXPECT LATER SHIFTS WILL TAKE PCPN CHC INTO LKLY CAT. LOOKS LIKE A GOOD SHOT AT RAIN AS MORE AMPLIFIED UPR TROF CONTRIBUTING TO DEEPER SFC LO. PCPN WILL TAKE MUCH OF THURS TO GET OUT OF FCST AREA WITH CLOUDS THINNING THURS NIGHT AS HI PRES RIDGE BUILDS IN. TEMPS...WARMED TEMPS UP A FEW DEGREES THRU WED AS LO LVL THICKNESSES/850 TEMPS HAVE COME IN A BIT WARMER ON 12Z RUNS. THIS MATCHES UP WELL WITH MAV GUID. EXTENDED...NEXT CHC PCPN WILL COME SATURDAY AS FRNTL BNDRY DROPS INTO GRT LKS. 00Z GFS ATTEMPTING TO REASSERT GRT LKS CUTOFF LO AND HIGHLY AMPLIFIED EASTERN CONUS TROF BEHIND THIS SYSTEM...BUT 12Z RUN HAS BACKED OFF ON THIS SOLN CONSIDERABLY. 12Z RUN MORE IN LINE WITH ECMWF...KEEPING MORE PROGRESSIVE UPR FLO ACRS REGION FOR END OF WEEKEND. HAVE LOWERED TEMPS A BIT FROM PREVIOUS FCST FOR SUN/MON...BUT PREFER 12Z GFS/ECMWF SOLN ATTM. .ILN...NONE. RYAN oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 915 PM EDT MON MAY 26 2003 LOCAL MAX OF SFC-925 HPA MOISTURE FLUX CONVERGENCE SHOWN ON 23Z RUC (AND 01Z REGIONAL SFC PLOT) EXTENDING FROM CLEARFIELD COUNTY...SE TO HUNTINGDON AND FRANKLIN COUNTIES. THIS FORCING WAS GENERATING AN INCREASING (THOUGH NARROW) BAND OF SHOWERS ALONG THE NOTED AXIS. RUC SHOWS THE MOISTURE CONVERGENCE STRENGTHENING FOR THE NEXT FEW HOURS AS ITS MAX SHIFTS TO NEAR THE INTERSECTION OF THE MASON/DIXON LINE WITH INTERSTATE 81 BETWEEN 03Z AND 04Z. AFTERWARD...THE FOCUS FOR SHOWERS SHOULD GREATLY DIMINISH. STILL ONE OR TWO TOWNS COULD RECEIVE 0.25" OR SLIGHTLY MORE SINCE THE RATHER COMPACT SHOWERS WILL BE TRAINING FROM NW TO SE. SO...FOR THE EVENING UPDATE...I WILL REMOVE LOW POPS FOR SHOWERS IN THE PREVIOUS AFTERNOON ZONES...AND GO WITH JUST ISOLATED SHOWERS ACROSS THE SCENT MTNS...ENDING AROUND MIDNIGHT. LIGHT WINDS AND PERIODS OF JUST PTLY CLOUDY SKIES WILL TIGHTEN UP THE LLVL TEMP/DEWPT SPREAD AND LEAD TO AREAS OF FOG DEVELOPING A FEW HOURS AFTER MIDNIGHT. SOME OF THE FOG COULD BE DENSE DURING THE PREDAWN HOURS. OTHERWISE...THE PREVIOUS ZFP LOOKS IN DECENT SHAPE W/RESPECT TO TUESDAY'S FCST. WILL EXTEND THE CHC OF SHOWERS THROUGH THE SUSQ VALLEY FOR THE AFTERNOON HOURS. 12Z SREF SHOWS A GREATER THAN 60% CHC OF 0.10" BTWN 12Z TUES AND 00Z WED ACROSS THE SCENT PARTS OF OUR FCST AREA...WITH ABOUT A 30-50 POP THROUGHOUT THE SUSQ VALLEY. 18Z ETA BUFKIT SUGGEST UP TO 0.25" POSSIBLE IN MANY AREAS BY 00Z WED. LOOKS PRACTICALLY LIKE DEJA VU CONCERNING THE TRACK OF THE UPPER SHORT WAVE AND LOCATION OF THE QUASI STNRY SFC BOUNDARY TUES NIGHT INTO WED. MAIN DIFF MAY BE THAT THE LOCATIONS OF THE ABOVE NOTED FEATURES MAY BE ABOUT 100-150 KM FURTHER EAST THAT LAST NIGHT. ALTHOUGH THE ERN PART OF OUR AREA WILL BE UNDER A FARILY POTENT EXIT REGION OF AN UPPER JET...THIS UPCOMING EVENT DOES NOT APPEAR TO HAVE THE DISTINCT COUPLED JET STRUCTURE AS WAS PRESENT 18-24 HOURS AGO. ................................................................. PREVIOUS AFTERNOON DISCUSSION BELOW ................................................................. STILL SOME LINGERING SHOWERS ACROSS CENTRAL PA THIS AFTERNOON WILL PERSIST INTO THE EARLY EVENING BEFORE DISSIPATING. SKIES MAY CLEAR FOR A FEW HOURS...BUT WITH PLENTY OF LOW LEVEL MOISTURE CLOUDS AND AREAS OF FOG WILL FORM AFTER MIDNIGHT. BY SUNRISE...CLOUDS AGAIN ALREADY BACK ON THE INCREASE AS NEXT IN SERIES OF UPPER LOWS MOVES OUT OF THE GREAT LAKES. PRECIP CHANCE AGAIN INCREASES BY AFTERNOON TUE AND CONTINUES INTO WED. TEMPS STRUGGLE TO WARM WITH PLENTY OF CLOUD COVER HANGING AROUND...SO HIGHS SLIGHTLY WARMER THAN TODAY FOR TUE AND WED. A BREAK IN THE PRECIP WED NIGHT INTO THU AS REGION WILL BE BETWEEN UPPER SYSTEMS. BUT THE SHOWERY WEATHER RETURNS FOR FRI INTO THE WEEKEND AS TEMPS CONTINUE ON THE COOL SIDE. FCSTID = 16 MDT 50 69 54 70 / 30 20 40 40 IPT 48 69 52 70 / 30 20 40 40 BFD 42 62 44 63 / 20 40 50 40 JST 45 64 47 65 / 20 40 50 40 AOO 49 69 51 70 / 30 30 40 40 UNV 46 68 51 69 / 30 30 40 40 SEG 49 69 53 70 / 30 20 40 40 LNS 50 69 55 70 / 30 20 40 40 THV 51 69 54 70 / 30 20 40 40 RXR .CTP... PA...NONE. $$ LAMBERT pa AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 945 AM MDT MON MAY 26 2003 CURRENT SURFACE MAP SHOW TROF ACROSS EASTERN MONTANA INTO EASTERN WYOMING. TIGHT PRESSURE GRADIENT ACROSS EASTERN PORTION OF CWA...WITH GUSTY SOUTHEAST WINDS. NARROW BAND OF MID LEVEL ACCAS ACROSS NORTHEAST WYOMING ALONG THE TROF. 12Z ETA/RUC SIMILAR IN KEEPING NARROW BAND OF INSTABILITY ALONG THE TROF THIS AFTERNOON WITH CAPE AROUND 1500 J/KG AND VERY LITTLE CAP. WILL GO WITH SCATTERED AFTERNOON THUNDERSTORMS ACROSS NORTHEAST WYOMING AND THE BLACK HILLS. FORECAST SOUNDINGS INDICATE MARGINAL SHEAR...HOWEVER IT DOES NOT APPEAR THAT THE MODELS ARE PICKING UP ON THE STRONGER SOUTHEAST WINDS RIGHT ALONG THE TROF. THEREFORE...SHEAR SHOULD BE SUFFICIENT FOR SUPERCELLS ALONG AND JUST AHEAD OF THE TROF. EAST OF THE BLACK HILLS...CAP SHOULD SUPPRESS ANY THUNDERSTORM ACTIVITY THIS AFTERNOON...BUT WILL HAVE A CHANCE LATER THIS EVENING AS TROF SLOWLY SLIDES EAST. UPDATED HAZARDOUS WEATHER OUTLOOK TO MENTION SLIGHT RISK OF SEVERE THUNDERSTORMS IN NORTHEAST WYOMING...IN LINE WITH 13Z SPC OUTLOOK. .UNR...NONE. $$ sd SOUTH CENTRAL TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 910 PM CDT MON MAY 25 2003 EAST-WEST FRONTAL BOUNDARY OVER CWA THIS EVENING WITH CONVECTION CONTG WELL TO THE SOUTHWEST OVER THE MEXICAN MOUNTAINS. THIS TSTM ACTIVITY NOT MAKING MUCH PROGRESS TOWARD THE RIO GRANDE RIVER ATTM AND CLOUD TOPS APPEAR TO BE WARMING. WILL LOWER POPS OVERNIGHT BUT KEEP CHC CATEGORY POPS ALONG THE RIO GRANDE AND SW COUNTIES AND SLIGHT CHC EAST...AS LATEST GFS/RUC CONT TO SHOW QPF INTO THE SW COUNTIES OVERNIGHT. 01/13/23 AFTN AFD... UPPER LOW OVER NORTHERN MEXICO CONTINUES TO RETROGRADE AWAY FROM TEXAS WHILE THE MASSIVE TROUGH OVER THE EASTERN U.S. FINALLY PUSHES THE COLD FRONT THROUGH TEXAS AND BRINGS DRIER AIR TO THE REGION. APPEARS OUR RAIN CHANCES ARE BETTER OUT WEST THROUGH TUESDAY THEN DWINDLES OFF TO NOTHING AREAWIDE BY THURSDAY. LOTS OF CLOUDINESS ASSOCIATED WITH THE COLD FRONT. SO WITH THIS SLOW MOVEMENT THROUGH OUR CWA, WILL KEEP THE MOSTLY CLOUDY CONDITIONS AND NEAR NORMAL HIGH TEMPS THROUGH WEDNESDAY. AS THE CLOUDINESS MOVES OUT WILL BRING MAX TEMPS BACK TO ABOVE NORMAL. OVERNIGHT LOWS WILL REMAIN NEAR SEASONAL LEVELS ALL WEEK LONG. EVENTHO NORTHWEST FLOW PATTERNS BRING US NEEDED RAIN FROM OVERNIGHT MCS'S, THE 500MB HEIGHTS ARE TOO HIGH NEXT WEEKEND TO LET ANY MOVE INTO CENTRAL TEXAS. .EWX...NONE. tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 1020 AM EDT MON MAY 26 2003 WILL MAKE COSMETIC UPDATES FOR THE AFTERNOON FORECASTS TO REMOVE MORNING REFERENCES. CURRENTLY...COMPLEX OF STORMS HAS PUSHED OFFSHORE ALONG WITH 925-850 MB OR LOW LEVEL JET CORE AND THETA-E RIDGE. FOR THE AFTN...THE MAIN FORECAST CONCERN WILL BE WHETHER OR NOT CONVECTION WILL FIRE. AIRMASS WILL MODIFY SIGNIFICANTLY DURING THE AFTERNOON WITH THE ANTICIPATED BREAKS IN THE CLOUD COVER AND THUS SOLAR HEATING. THE FRONT...WHICH CURRENTLY EXTENDS FROM JUST OFF THE LOWER MD/VA ERN SHORE SW THROUGH NEAR SUFFOLK AND AHOSKIE NC...IS EXPECTED TO REMAIN NEARLY STATIONARY THIS AFTN PARALLEL TO 700/500 MB FLOW. WHILE THERMAL DIFFERENCES ARE EXPECTED TO BE MINIMAL ON EITHER SIDE OF THE FRONT...THERE WILL BE A GRADIENT IN SURFACE DEWPOINT. SLIGHTLY DRIER LOW LEVEL AIR IS BEING ADVECTED IN BEHIND THE FRONT INTO CENTRAL VA...PER THE WEAK NW/W FLOW DOWNSLOPING E OF THE MNTNS. ALONG AND E OF THE FRONT...SURFACE DEWPOINTS ARE EXPECTED TO REMAIN IN THE 65-70 DEG RANGE. THUS THE BEST CHANCE FOR ORGANIZED CONVECTION THIS AFTN WILL BE ACROSS EXTREME SE VA AND NE NC...IN CLOSE PROXIMITY TO THE FRONT WHERE THE LOW LEVEL CONVERGENCE OR FOCUS FOR CONVECTION WILL BE PRESENT...ALONG WITH THE HIGHER SURFACE LAYER MOISTURE. WILL CONTINUE WITH THE 30-50% PROBABILITIES OVER THE REGION...AGAIN WITH THE HIGHEST PROBS OVER THE SERN ZONES. THE SEVERE WEATHER RISK WILL ALSO BE GREATEST OVER FAR SERN VA AND NE NC...PER THE SPC DAY 1 OUTLOOK. MAIN LIMITING FACTORS...AS WAS MENTIONED YDAY...IS THE MARGINAL INSTBY ALONG WITH THE BEST LOW LEVEL INFLOW/MOISTURE POOLING NOW SHIFTED E OF THE AREA. IN TERMS OF Q-G FORCING...ANOTHER SHOT OF UPPER LEVEL DIVERGENCE/850-500 MB QVECTOR CONVERGENCE (ALBEIT WEAKER) IS EXPECTED OVER NRN NC TOWARD 00Z. MODIFIED CAPES OF ~2000 J/KG ARE NOTED PER BOTH OBSERVED AND RUC SOUNDINGS...BASED ON A SURFACE T/TD PROFILE OF 82/67. SHEAR PROFILES ARE MORE IMPRESSIVE...WITH 40-45KT 500 MB WINDS NOTED ALONG WITH 40KTS OF 0-6KM SHEAR. HODOGRAPHS SHOW AN INCREASINGLY LINEAR SHEAR PROFILE LATER TODAY...EVEN E/SE OF THE FRONT...WITH SQUALL LINE CONVECTION/BOWING SEGMENTS MOST LIKELY. GIVEN THE HIGH BULK SHEAR (~40 KTS) HWVR...SPLITTING CELLS/RIGHT MOVING SUPERCELLS WILL ALSO BE POSSIBLE. LASTLY...MID LEVEL DEWPOINT DEPRESSIONS BTWN 5-10C LATER THIS AFTN/EVENING WILL ALLOW FOR DRY AIR INTRUSION AND THUS ENHANCE THE EVAPORATION/ DOWNBURST POTENTIAL. WILL MONITOR TRENDS FOR THE AFTERNOON...DEFINITELY SOMETHING TO WATCH. .AKQ... .MD...NONE. .NC...NONE. .VA...NONE. HURLEY PREVIOUS AFD BELOW... ------------------------------------------------------------------ OVERVIEW: MASSIVE AMTS OF RAIN OVER THE PAST 12 HRS ACROSS PRNS OF CNTRL VA...MAINLY W OF I-95. THE HARDEST HIT CNTYS HAVE BEEN MECKLENBURG...LUNENBURG...AND NOTTOWAY WITH RADAR ESTMD PRECIP AMTS OF OVER 6 INCHES SINCE SUN EVENG. DINWIDDIE/CHESTERFIELD CNTYS HAVE HAD SMWHT LIGHTER AMTS...BUT STILL AN IMPRESSIVE 3 TO 5 INCHES. UPR JET DYNMCS W/ A LLVL JET OVER A THETA E RDG SET UP YSTDY SET THE BNDRY FOR A VRY PROFICIENT TRAINING OF STRMS OVER THE SAME AREA FOR SEVERAL HRS. PRECIP RATES OF ABOUT 2 IN/HR WERE OCSNLY OBSVD. SHORT TERM: THANKFULLY BACK EDGE OF PRECIP HAS FNLY PUSHED INTO THE WRN PRN OF THE CWA OVR THE PAST HR...W/LLVL FLW TURNING MORE TO THE W TDY...ALTHOUGH STAYING A BIT MORE SW ACRS THE FAR SE ZONES (NE NC). OVERALL XPCT TDY TO SEE A BREAK IN THE HVY PRECIP...BUT WILL KEEP CHC POPS FOR SHWRS/TSTMS ALL ZONES W/ ABUNDANT LLVL MSTR/INSTBTY STILL PRESENT. WITH WDSPRD HVY PRECIP AMTS NOT XPCTED TDY...HAVE OPTED TO CANCEL FLOOD WATCH ATTM. W/ UPR LOW STILL SPINNING OVR THE GRT LAKES THRU MIDWEEK...STILL EXPECTING UNSETTLED WX PATTERN W/ CHC POPS FOR THE PERIOD...COOLED TEMPS SMWHT COASTAL AREAS ON TUE AS MDLS HINT AT SOME WEAK NE LLVL FLW/WEDGE TYPE OF FEATURE. EXTENDED: NO CHANGES TO GOING FCST W/ EXCEPTION OF COOLING TEMPS A FEW DGRS BASED ON LATEST GDNC. MARINE: GNRLY LGT WINDS...AND YSTRDY'S RESIDUAL ERLY SWELL HAS TAPERED OFF SO ALL IS QUIET. BROWN va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 940 PM EDT MON MAY 26 2003 AGAIN DEBATE CONTINUES WHETHER OR NOT CLOUDS BREAK UP. PLENTY OF MOISTURE IN THE LOWEST 8KFT AND NOT MUCH WAA AS LIGHT NORTHERLY WINDS PERSIST. OVC CONDITIONS OVER THE COAL FIELDS HANGING TUFF. LATEST FCST SOUNDINGS FROM THE 40KM RUC DEPICT NEARLY SATURATED CONDITIONS BETWEEN 7-9KFT...AND EVEN IF BREAKS OCCUR SHARP INVERSION AT H95 TO GENERATE IFR CIGS. AT THIS POINT WILL UPDATE FORECAST TO INCLUDE VARIABLE CLOUDS AND BUMP TEMPS UP. REST ON TRACK. .RLX... WV...NONE. OH...NONE. VA...NONE. KY...NONE. 99 ******************************************************************** 252 PM EDT MON MAY 26 2003 TONIGHT AND TUESDAY... MODELS IN GOOD AGREEMENT IN KEEPING SHORT WAVE CURRENTLY DROPPING ACROSS THE MID MISSISSIPPI VALLEY SOUTH OF OUR CWA LATE TONIGHT AND TUESDAY. HOWEVER...MAIN SOUTHEASTERN CANADIAN VORTEX DIVES SOUTH BEHIND THIS SHORT WAVE OVER THE OHIO VALLEY ON TUESDAY. THERE WILL BE QUITE SOME COLD AIR ALOFT AND SOME MOISTURE AVAILABLE FOR MAINLY AFTERNOON SCATTERED SHOWERS AND THUNDERSTORMS. EXPECT ENOUGH CLEARING TONIGHT FOR SOME FOG IN FAVORED AREAS...THEN FOR SOME HEATING ON TUESDAY TO DESTABILIZE FOR AFTERNOON CONVECTION. GUIDANCE TEMPERATURES VERY CLOSE AND LOOK REASONABLE. TUESDAY NIGHT THROUGH THURSDAY NIGHT... OHIO VALLEY SHORT WAVE EXITS FIRST THING TUESDAY EVENING...JUST AS MAIN UPPER LOW OVER LAKES SETTLES SOUTHWARD INTO AREA. THIS UPPER LOW EXITS WEDNESDAY...ITS PASSAGE DURING WRONG TIME OF DAY W/R THUNDERSTORMS BUT WILL KEEP EASTERN ZONES WEDNESDAY AFTERNOON. NEXT SYSTEM APPEARS QUICKER STILL AND WILL INTRODUCE POPS BY THURSDAY MORNING...UP TO 50 PERCENT WEST BY THEN. FRONT PLOWS THROUGH EARLY THURSDAY WITH GENEROUS WRAP AROUND OVER ABOUT ALL OF AREA BY THURSDAY AFTERNOON GIVEN SOUTHERN TRACK OF SYSTEM. COULD SEE A MORE NORTHERN TRACK RESULTING IN MORE OF A DRY SLOT AROUND MIDDAY THURSDAY BUT TOO FAST/NARROW OF A FEATURE TO RESOLVE AT THIS DISTANCE. THUNDERSTORMS WITH FRONT BASED ON STRENGTH OF UPPER DYNAMICS BUT TIME OF DAY COULD PRECLUDE SEVERE. STRONG WINDS BEHIND FRONT WITH GOOD GRADIENT AND ALIGNMENT IN THE VERTICAL. SHOWER CHANCE WELL INTO THURSDAY NIGHT ON THIS STRONG WRAP AROUND FLOW. NO LARGE DEVIATIONS FROM MOS. FRIDAY THROUGH SUNDAY... MODELS IN REASONABLE AGREEMENT WITH PATTERN THROUGH EXTENDED. SHOULD SEE A DRY DAY ON FRIDAY AS AREA FALLS UNDER UPPER RIDGE ON HEELS OF EXITING SYSTEM. COLD FRONT TO PASS THROUGH REGION ON SATURDAY BRINGING CHANCE OF SHOWERS AND THUNDERSTORMS AS UPPER LOW DIGS INTO GREAT LAKES REGION ONCE AGAIN. UPPER LOW SPINS OVER LAKES INTO MONDAY AND CWA IS ON SOUTHERN PERIPHERY. HAVE PLAYED DRY FORECAST SUN/MON AS THERE IS LITTLE FORCING WITH UPPER LOW AND UNCERTAINTY AS TO WHAT MOISTURE WILL BE AVAILABLE. HAVE PLAYED MORE CLOUDS AND COOLER TEMPS AS A RESULT. JMV/TRM/HC ******************************************************************** 1030 AM EDT MON MAY 26 2003 UPDATED FORECAST THIS AFTERNOON TO KEEP LOTS OF CLOUDS MOST AREAS AND THUS LOWER MAXES A BIT. 12Z SOUNDINGS FROM ILN AND PIT SHOW LOTS OF LINGERING LOW LEVEL MOISTURE. ANY HEATING THAT OCCURS SHOULD ALLOW CLOUDS TO QUICKLY FILL BACK IN UNDER DECENT TEMPERATURE INVERSION AS SHOWN ON ILN SOUNDING AND FORECAST MESOETA SOUNDINGS. WILL ALSO KEEP SPRINKLES IN CENTRAL AND NORTHERN MOUNTAINS OF WEST VIRGINIA. JMV ******************************************************************** 440 AM EDT MON MAY 26 2003 ...TODAY AND TONIGHT... DRIZZLE AND LIGHT SHOWERS REMAIN ACROSS THE CENTRAL AND EASTERN PORTIONS OF WEST VIRGINIA THIS MORNING. OVERALL QPF SUNDAY WAS FAIRLY LIGHT...NOT TAKING AWAY FROM VARIOUS CELEBRATIONS DURING THE HOLIDAY WEEKEND. TOTAL PRECIP AVERAGED AROUND A TENTH OF AN INCH...WITH SLIGHTLY MORE RECORDED ACROSS THE EASTERN MOUNTAINS. MAX POP TODAY WILL BE SLIGHT AS SHOWERS CONTINUE TO EXIT THE REGION. CLOUDS DO NOT SEEM AS THICK AS THE PREVIOUS FORECAST WOULD HAVE THEM TO BE. WILL KEEP MOSTLY CLOUDY CONDITION ACROSS THE MOUNTAINS THROUGHOUT MUCH OF THE DAYLIGHT HOURS...BUT DO EXPECT A FEW MORE GLIMMERS OF SUNSHINE TO PEEK THROUGH CLOUDS ACROSS MUCH OF THE REMAINDER OF THE FORECAST AREA. NO OTHER CHANGES MADE...JUST SMALL ADJUSTMENTS. ...TUESDAY THROUGH SUNDAY... A SERIES OF VORTMAX ROTATING THROUGH THE UPPER LOW WILL KEEP A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FORECAST AREA INTO WEDNESDAY. A FRONTAL BOUNDARY APPROACHING THE REGION ON THURSDAY WILL CONTINUE A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH FRIDAY MORNING. DRY CONDITIONS FOR FRIDAY NIGHT. ANOTHER FRONT WILL APPROACH ON SATURDAY AND KEEP SHOWERS AND THUNDERSTORMS IN THE REGION THROUGH SUNDAY. THE TEMPERATURES ARE REASONABLE WITH MINOR ADJUSTMENTS. KF/ELW wv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 350 AM EDT TUE MAY 27 2003 THE MAIN CONCERN WITH THIS MORNING FORECAST IS THE ONSET OF SHOWERS ON WEDNESDAY. WATER VAPOR IMAGERY AND RUC/ETA SHOWING A LONGWAVE TROUGH WITH AN EMBEDDED CLOSED LOW OVER THE LOWER GREAT LAKES. A HIGH OVER THE SOUTHWESTERN STATES HAS A RIDGE STRETCHING NORTHEAST THROUGH MINNESOTA AND ONTARIO. SHORTWAVES ROTATING THROUGH THE BASE OF THIS LOW ARE OVER THE WESTERN U.P. AND OVER EASTERN SASKATCHEWAN. THESE ARE WORKING THROUGH THE RIDGE WEAKENING THE RIDGE. SURFACE ANALYSIS SHOWING A BROAD RIDGE REMAINING OVER THE CENTRAL PLAINS AND THE UPPER GREAT LAKES. A COLD FRONT EXTENDS SOUTH FROM A LOW OVER NORTHERN MANITOBA INTO THE DAKOTAS. SCATTERED SHOWERS AND THUNDERSTORM ARE OVER THE DAKOTAS AND THE CENTRAL PLAINS IN ASSOCIATION WITH THE COLD FRONT AND SHORTWAVE ENERGY SLIDING THROUGH THOSE AREAS. DRY AIR AHEAD OF THE FRONT AND UNDER THE MID LEVEL RIDGE IS KEEPING SKIES MOSTLY CLEAR OVER THE NORTHERN PLAINS AND THE FORECAST AREA. THE MID LEVEL LOW WILL REMAIN STATIONARY OVER THE LOWER GREAT LAKES TODAY. SHORTWAVES WILL WEAKEN THE RIDGE EVEN MORE OVER MINNESOTA AS IT SLIDES INTO LAKE SUPERIOR. THE FIRST SHORTWAVE WILL MOVE THROUGH WISCONSIN...FOLLOWED BY A DEEPER SHORTWAVE WHICH WILL SLIDE INTO MINNESOTA. THE COLD FRONT ASSOCIATED WITH THE SHORTWAVE WILL RELOCATE OVER THE ARROWHEAD OF MINNESOTA BY 00Z WEDNESDAY. 300K ISENTROPIC LIFT WILL INCREASE OVER THE FORECAST AREA TODAY AHEAD OF THE APPROACHING FRONT. HOWEVER...THE DRY AIR OVER THE FORECAST AREA WILL PREVENT ANY PRECIPITATION. ETA SOUNDING FORECAST SHOWING THE AIR MASS WILL BE TOO DRY TO PREVENT CLOUDS FROM DEVELOPING... EXCEPT FOR THE FAR WEST WHERE SOME THIN HIGH CLOUDS ARE POSSIBLE. UNDER THE INFLUENCE OF THE SURFACE RIDGE WINDS WILL REMAIN LIGHT. TRAJECTORY FORECAST SUPPORTS TEMPERATURES OVER THE FORECAST AREA A LITTLE WARMER THAN YESTERDAYS. SINCE WINDS WILL BE LIGHT AND SURFACE HEATING WILL REACH INTO THE 70S AGAIN...EXPECT TO SEE LAKE BREEZES KICK IN AROUND MID DAY. THIS WILL MAKE FORECASTING THE MAX TEMPERATURES TODAY TRICKY IN TRYING TO TIME AND EXTENT OF THE LAKE BREEZES. THE MID LEVEL CLOSED LOW WILL SLIDE INTO THE EASTERN OHIO VALLEY TONIGHT. SHORTWAVE ENERGY WILL FURTHER WEAK THE RIDGE OVER LAKE SUPERIOR AS IT MOVES INTO THE EASTERN U.P. THE COLD FRONT AND THE MID LEVEL TROUGH WILL SLIDE INTO CENTRAL U.P. HIGHER DEW POINTS AND MOISTURE WILL ACCOMPANY THE FRONT AS IT MOVES INTO THE U.P. OVERRUNNING OVER THE FRONT WILL TRIGGER SHOWERS AND THUNDERSTORMS. THE THETA-E RIDGE WILL MOVE INTO WESTERN U.P. THE MODELS SHOWING THE MAIN ACTIVITY WILL REACH THE SOUTH PART OF THE FORECAST AREA...AND THAT THE PRECIPITATION BAND WILL BE QUITE NARROW LASTING ONLY A FEW HOURS. THE HEAVIEST ACTIVITIES IN THE FORECAST AREA WILL BE ALONG THE WISCONSIN BORDER. THE MID LEVEL LOW WILL DRIVE OFF THE MID ATLANTIC COAST ON WEDNESDAY. A SHORTWAVE WILL SHIFT ACROSS THE FORECAST AREA. THE COLD FRONT WILL MOVE INTO NORTHERN LOWER MICHIGAN AND EASTERN ONTARIO. MOISTURE WILL STILL BE QUITE HIGH OVER EASTERN U.P. IT WILL DRY OUT FAIRLY RAPIDLY OVER THE WESTERN COUNTIES OF THE CWA. SHORTWAVE ENERGY WILL MOVE INTO NORTHERN LOWER MICHIGAN ON WEDNESDAY NIGHT. DRY AIR WILL CONTINUE TO SPREAD ACROSS THE FORECAST AREA AS THE FRONT MAKES ITS WAY INTO THE LOWER GREAT LAKES...AND A SURFACE RIDGE MOVES OVER THE FORECAST AREA AGAIN. MEAN SURFACE-500 RELATIVE HUMIDITIES WILL BE LESS THAN 40 PERCENT. A BROAD RIDGE WILL EXPAND OVER MUCH OF THE CENTRAL AND SOUTHERN PLAINS. FRONTOGENESIS WILL TAKE PLACE OVER WESTERN ONTARIO AND CENTRAL MANITOBA. SURFACE RIDGE WILL BE OVER THE FORECAST AREA AND SHOULD PRODUCE MOSTLY CLEAR SKIES. THE SURFACE RIDGE WILL REMAIN OVER THE FORECAST AREA ON THURSDAY. THE SHORTWAVE ENERGY WILL SHIFT INTO LOWER MICHIGAN. A WEAK SHORTWAVE WILL MOVE INTO LAKE SUPERIOR BY LATE THURSDAY. DRY CONDITIONS REMAIN OVER THE FORECAST AREA. .MQT...NONE. DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 240 AM EDT TUE MAY 27 2003 ******************************************************************** 240 AM EDT TUE MAY 27 2003 ...TODAY AND TONIGHT... PESKY UPPER LEVEL LOW WILL BEGIN A SLOW DIVE SOUTHWARD TOWARD THE REGION. WILL KEEP MENTION OF DAYTIME SHOWERS AND THUNDERSTORMS IN THE FORECAST AREA. DUE TO LIGHT LOW LEVEL WINDS...ANY THUNDERSTORMS THAT DO DEVELOP COULD BE SLOW MOVERS. NOT MANY CHANGES NEEDED IN THE FIRST 24 HOURS. ...WEDNESDAY THROUGH MONDAY... THE UPPER LOW WILL MOVE ACROSS THE FORECAST AREA WHICH WILL COMBINE WITH A VORTMAX. THE VORTMAX WILL EXIT THE EASTERN PORTION OF THE AREA WHILE ANOTHER VORTMAX AND UPPER LEVEL TROF MOVES ACROSS THE REGION THROUGH THURSDAY. THE CHANCE OF SHOWERS AND THUNDERSTORMS ARE REASONABLE. NORTHWEST FLOW AND DRIER AIR WILL FILTER INTO THE AREA ON FRIDAY. A SURFACE FRONT WILL MOVE INTO THE FORECAST AREA BY SATURDAY...CONTINUE THE CHANCE OF SHOWERS AND THUNDERSTORMS. THE FRONT WILL BE EAST OF THE FORECAST AREA BY SUNDAY...AS HIGH PRESSURE BUILD INTO THE REGION. THE DRY FORECAST SEEM REASONABLE FOR SUNDAY AND MONDAY. THE TEMPERATURES ARE IN THE BALLPARK. .RLX... WV...NONE. OH...NONE. VA...NONE. KY...NONE. .END/ KF/ELW ******************************************************************** 940 PM EDT MON MAY 26 2003 AGAIN DEBATE CONTINUES WHETHER OR NOT CLOUDS BREAK UP. PLENTY OF MOISTURE IN THE LOWEST 8KFT AND NOT MUCH WAA AS LIGHT NORTHERLY WINDS PERSIST. OVC CONDITIONS OVER THE COAL FIELDS HANGING TUFF. LATEST FCST SOUNDINGS FROM THE 40KM RUC DEPICT NEARLY SATURATED CONDITIONS BETWEEN 7-9KFT...AND EVEN IF BREAKS OCCUR SHARP INVERSION AT H95 TO GENERATE IFR CIGS. AT THIS POINT WILL UPDATE FORECAST TO INCLUDE VARIABLE CLOUDS AND BUMP TEMPS UP. REST ON TRACK. 99 ******************************************************************** 252 PM EDT MON MAY 26 2003 TONIGHT AND TUESDAY... MODELS IN GOOD AGREEMENT IN KEEPING SHORT WAVE CURRENTLY DROPPING ACROSS THE MID MISSISSIPPI VALLEY SOUTH OF OUR CWA LATE TONIGHT AND TUESDAY. HOWEVER...MAIN SOUTHEASTERN CANADIAN VORTEX DIVES SOUTH BEHIND THIS SHORT WAVE OVER THE OHIO VALLEY ON TUESDAY. THERE WILL BE QUITE SOME COLD AIR ALOFT AND SOME MOISTURE AVAILABLE FOR MAINLY AFTERNOON SCATTERED SHOWERS AND THUNDERSTORMS. EXPECT ENOUGH CLEARING TONIGHT FOR SOME FOG IN FAVORED AREAS...THEN FOR SOME HEATING ON TUESDAY TO DESTABILIZE FOR AFTERNOON CONVECTION. GUIDANCE TEMPERATURES VERY CLOSE AND LOOK REASONABLE. TUESDAY NIGHT THROUGH THURSDAY NIGHT... OHIO VALLEY SHORT WAVE EXITS FIRST THING TUESDAY EVENING...JUST AS MAIN UPPER LOW OVER LAKES SETTLES SOUTHWARD INTO AREA. THIS UPPER LOW EXITS WEDNESDAY...ITS PASSAGE DURING WRONG TIME OF DAY W/R THUNDERSTORMS BUT WILL KEEP EASTERN ZONES WEDNESDAY AFTERNOON. NEXT SYSTEM APPEARS QUICKER STILL AND WILL INTRODUCE POPS BY THURSDAY MORNING...UP TO 50 PERCENT WEST BY THEN. FRONT PLOWS THROUGH EARLY THURSDAY WITH GENEROUS WRAP AROUND OVER ABOUT ALL OF AREA BY THURSDAY AFTERNOON GIVEN SOUTHERN TRACK OF SYSTEM. COULD SEE A MORE NORTHERN TRACK RESULTING IN MORE OF A DRY SLOT AROUND MIDDAY THURSDAY BUT TOO FAST/NARROW OF A FEATURE TO RESOLVE AT THIS DISTANCE. THUNDERSTORMS WITH FRONT BASED ON STRENGTH OF UPPER DYNAMICS BUT TIME OF DAY COULD PRECLUDE SEVERE. STRONG WINDS BEHIND FRONT WITH GOOD GRADIENT AND ALIGNMENT IN THE VERTICAL. SHOWER CHANCE WELL INTO THURSDAY NIGHT ON THIS STRONG WRAP AROUND FLOW. NO LARGE DEVIATIONS FROM MOS. FRIDAY THROUGH SUNDAY... MODELS IN REASONABLE AGREEMENT WITH PATTERN THROUGH EXTENDED. SHOULD SEE A DRY DAY ON FRIDAY AS AREA FALLS UNDER UPPER RIDGE ON HEELS OF EXITING SYSTEM. COLD FRONT TO PASS THROUGH REGION ON SATURDAY BRINGING CHANCE OF SHOWERS AND THUNDERSTORMS AS UPPER LOW DIGS INTO GREAT LAKES REGION ONCE AGAIN. UPPER LOW SPINS OVER LAKES INTO MONDAY AND CWA IS ON SOUTHERN PERIPHERY. HAVE PLAYED DRY FORECAST SUN/MON AS THERE IS LITTLE FORCING WITH UPPER LOW AND UNCERTAINTY AS TO WHAT MOISTURE WILL BE AVAILABLE. HAVE PLAYED MORE CLOUDS AND COOLER TEMPS AS A RESULT. JMV/TRM/HC ******************************************************************** 1030 AM EDT MON MAY 26 2003 UPDATED FORECAST THIS AFTERNOON TO KEEP LOTS OF CLOUDS MOST AREAS AND THUS LOWER MAXES A BIT. 12Z SOUNDINGS FROM ILN AND PIT SHOW LOTS OF LINGERING LOW LEVEL MOISTURE. ANY HEATING THAT OCCURS SHOULD ALLOW CLOUDS TO QUICKLY FILL BACK IN UNDER DECENT TEMPERATURE INVERSION AS SHOWN ON ILN SOUNDING AND FORECAST MESOETA SOUNDINGS. WILL ALSO KEEP SPRINKLES IN CENTRAL AND NORTHERN MOUNTAINS OF WEST VIRGINIA. JMV ******************************************************************** wv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI ISSUED BY NWS MARQUETTE MI 1003 AM EDT TUE MAY 27 2003 MAIN FORECAST CONCERN FOR THIS AFTERNOON ARE SHOWER CHANCES. UPPER LOW CURRENTLY NEAR BUFFALO CONTINUES TO SLOWLY RETROGRADE W THIS MORNING...AS THE KICKER S/WV OVER THE HIGH PLAINS IS NOT CLOSE ENOUGH TO GIVE IT A PUSH EAST. AS A RESULT...THE LOW SHOULD BE OVER EASTERN LAKE ERIE THIS AFTN. A LITTLE INCREASE IN MOISTURE IS NOTED FROM SATELLITE PICTURES AS A WEAK S/WV ROTATES THRU THE CWFA THIS MORNING. WATER VAPOR LOOP CONTINUES TO SUGGEST MORE MOISTURE WRAPPING AROUND THE UPPER LOW...WITH THE BEST MOISTURE CONFINED TO THE S/E PARTS OF THE CWFA. MDLS SHOW WARMING ALOFT TODAY...ESPECIALLY N AND W AS THE UPR RIDGE AXIS BUILDS TO THE NW OF THE AREA. AGREE WITH PREV FCST THAT THIS INCREASING CAP SHOULD INHIBIT ANY SHOWER ACTIVITY OVER THE FAR N AND W. HOWEVER...THE SRN/ERN CWFA DOES NOT SEE THIS WARMING TODAY DUE TO THE CLOSER PROXIMITY TO THE LOW. SO...INSTABILITY SHOWERS SHOULD DEVELOP THIS AFTN OVER THE S HALF OF THE CWFA THIS AFTN OVER THE S HALF OF THE CWFA. MDL CAPE VALUES RISE TO NEARLY 300 J/KG BASED ON SFC PROFILE OF 63/50. INCREASING THAT TO FCST T/TD OF 68/53 YIELDS CAPE VALUES OF 500-600 J/KG...WHICH IS DEFIANTLY SUFFICIENT FOR SHOWER ACTIVITY. 700-500MB LAPSE RATES PER RUC FCST ALSO AROUND 6.0 C/KM WHICH WOULD SUPPORT SOME SHOWER ACTIVITY. NOT MUCH LOW LVL FORCING...BUT LAKE BREEZE BOUNDARIES SHOULD ALLOW ENOUGH LOW LVL LIFT TO GENERATE THE SHOWER ACTIVITY. OTHERWISE...TEMPS LOOK FINE WITH MOSTLY SUNNY SKIES THIS MORNING BECOMING PTCLDY THIS AFTN AS DIURNAL CU DEVELOP. FOR NOW...NO ZFP UPDATE IS NEEDED...BUT WILL NEED TO MONITOR TEMPS ESPECIALLY IF THERE IS A LITTLE MORE SUNSHINE THRU EARLY AFTN. .APX...NONE. $$ MRD mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 953 AM EDT TUE MAY 27 2003 NICE LATE MAY DAY UNDERWAY ACROSS FCST AREA. WITH CLR SKIES AND LGT WINDS...TEMPS ARE THE ONLY FCST ISSUE. WV IMAGERY SHOWS MID/UPPER LOW SPINNING OVER THE ERN LAKES WITH A RIDGE EXTENDING FROM THE CNTRL PLAINS TO HUDSON BAY. SHORTWAVE WAS TRACKING INTO THE NRN PLAINS...ACCOMPANIED BY SOME SHRA/TSRA. VIS IMAGERY SHOWS CLR SKIES ACROSS UPPER MI. WELL ELEVATED SMOKE LAYER FROM FOREST FIRES IN RUSSIA CONTINUES TO DRIFT OVER THE AREA...BUT IT IS NOT NEARLY AS THICK AS SEEN YESTERDAY. 12Z KINL/CWPL SOUNDINGS ARE QUITE DRY IN THE LOW-MID LEVELS AND SUGGEST NO POTENTIAL FOR CU WITH CONVECTIVE TEMPS OVER 100F. STEEP NEAR DRY ADIABATIC LAPSE RATES FROM TOP OF NOCTURNAL INVERSION TO 750MB INDICATES DEEP MIXED LAYER THIS AFTN APPROACHING 700MB. THIS YIELDS HIGHS INTO THE LOWER 80S. ON THE OTHER HAND...KAPX/KGRB SOUNDINGS ARE MORE MOIST IN THE LOW LEVELS AND SUPPORT CU DEVELOPMENT AS CONVECTIVE TEMPS WILL BE ACHIEVED. MIXING TO AROUND 800MB YIELDS HIGHS IN THE LOWER 70S. DESPITE THE MORE MOIST APPEARANCE...WIND FLOW IN THE LOW-MID LEVELS IS NERLY...PRODUCING ADVECTION OF DRIER AIR INTO UPPER MI FROM ONTARIO. IN FACT...RUC FCST SOUNDINGS OVER FCST AREA DEPICT A MUCH DRIER ENVIRONMENT WITH STEEP LAPSE RATES...SIMILAR TO KINL/CWPL SOUNDINGS. SO...WILL BUMP UP HIGHS A COUPLE OF DEGREES ALL AREAS AWAY FROM GREAT LAKES...MORE INLINE WITH KINL/CWPL SOUNDINGS. EXPECT HIGHS NEAR 80 OVER CNTRL/W WELL AWAY FROM COOLING INFLUENCE OF LAKE SUPERIOR. .MQT...NONE. ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 958 AM EDT TUE MAY 27 2003 RAIN CONTG TO MV NE THIS AM...SHUD BE OFF THE CST BY NOON. CONSIDERABLE CLDNSS SHUD KP MAX TEMPS DWN THIS AFTN. WL LWR THEM A FEW DEGREES. THIS CUD DCRS OUR CHGS FOR SVR THIS AFTN ALSO. HWVR SHUD BE IN RR QUAD OF JET THIS AFTN...SO WL KP TSTMS IN FCST BUT LWR POPS SUMWHAT. SFC LO OFF CPLKOUT WI BNDRY XNTNDG BCK TO ANTHR WV ALNG THE NC/SC BRDR THEN SW. LTST RUC SWNGS BNDRY TO THE SE AND HAS IT ALNG THE CST BY 00Z WHILE ETA12 KPS IT INLND AND HAS LO FRTHR N THAN CRRNT FCST. BASED ON 12Z UPR LVL ANALYSES...WL GO WI RUC SOLN FOR THIS AFTN. THRFR WL UPDATE WND FIELDS ACCORDINGLY. .MHX...NONE CGG-G nc FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 950 AM CDT TUE MAY 27 2003 120 KNOT UPPER JET APPROACHING AT MT/ALB BORDER AND MAY ARRIVE IN TIME TO BE THE KICKER TO SEVERE THUNDERSTORMS THIS AFTERNOON. DEW POINTS IN EXCESS OF 55F WILL FEED THE PROBLEM WITH DECENT LOW LEVEL CONVERGENCE TO COMPLETE JET COUPLET. CAPE REACHES 1400 J/KG NEAR BDE BY 00Z ACCORDING TO ETA BUT ABOUT HALF THAT IN RUC. DIFFERENCE APPEARS TO BE HIGHER TEMPERATURES AND DEW POINTS BY ABOUT 5F IN BOTH GFS AND ETA...BUT CANNOT YET SEE 60+F DEW POINTS REACHING HERE TODAY. RUC SOUNDING ONLY DROPS LFC AT BDE DOWN TO 9500 FT AND NO LOWER THAN 7500 FT ELSEWHERE...VS. 5000-7500 FT IN ETA. SO WILL HAVE TO WATCH THESE TEMPERATURES/DEW POINTS CLOSELY TODAY TO POINT THE WAY TO SEVERE POTENTIAL. SINCE THE SIGNIFICANT PARAMETERS PLAYERS HAVE NOT COME TOGETHER YET SEVERE CONVECTION COULD POSSIBLY INITIATE ALMOST ANYWHERE EXCEPT DVL SET...IF THE DEW POINTS RISE ENOUGH. CURRENT FORECAST IS APPROPRIATELY BROADBRUSHED AND WILL PROBABLY CHANGE LITTLE OF ZONES FOR NOW. BUT WILL NEED TO UPDATE SOME OF THE GRIDS. .FGF...NONE. $$ GV nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 1050 AM EDT TUE MAY 27 2003 ******************************************************************** 1050 AM EDT TUE MAY 27 2003 RADAR AND SATELLITE SHOW WAVE MOVING FROM OH INTO WV. WILL UPDATE FORECAST TO UP POPS IN AREAS IN FRONT OF THE WAVE. .RLX... WV...NONE. OH...NONE. VA...NONE. KY...NONE. .END/RPY ******************************************************************** 240 AM EDT TUE MAY 27 2003 ...TODAY AND TONIGHT... PESKY UPPER LEVEL LOW WILL BEGIN A SLOW DIVE SOUTHWARD TOWARD THE REGION. WILL KEEP MENTION OF DAYTIME SHOWERS AND THUNDERSTORMS IN THE FORECAST AREA. DUE TO LIGHT LOW LEVEL WINDS...ANY THUNDERSTORMS THAT DO DEVELOP COULD BE SLOW MOVERS. NOT MANY CHANGES NEEDED IN THE FIRST 24 HOURS. ...WEDNESDAY THROUGH MONDAY... THE UPPER LOW WILL MOVE ACROSS THE FORECAST AREA WHICH WILL COMBINE WITH A VORTMAX. THE VORTMAX WILL EXIT THE EASTERN PORTION OF THE AREA WHILE ANOTHER VORTMAX AND UPPER LEVEL TROF MOVES ACROSS THE REGION THROUGH THURSDAY. THE CHANCE OF SHOWERS AND THUNDERSTORMS ARE REASONABLE. NORTHWEST FLOW AND DRIER AIR WILL FILTER INTO THE AREA ON FRIDAY. A SURFACE FRONT WILL MOVE INTO THE FORECAST AREA BY SATURDAY...CONTINUE THE CHANCE OF SHOWERS AND THUNDERSTORMS. THE FRONT WILL BE EAST OF THE FORECAST AREA BY SUNDAY...AS HIGH PRESSURE BUILD INTO THE REGION. THE DRY FORECAST SEEM REASONABLE FOR SUNDAY AND MONDAY. THE TEMPERATURES ARE IN THE BALLPARK. .END/ KF/ELW ******************************************************************** 940 PM EDT MON MAY 26 2003 AGAIN DEBATE CONTINUES WHETHER OR NOT CLOUDS BREAK UP. PLENTY OF MOISTURE IN THE LOWEST 8KFT AND NOT MUCH WAA AS LIGHT NORTHERLY WINDS PERSIST. OVC CONDITIONS OVER THE COAL FIELDS HANGING TUFF. LATEST FCST SOUNDINGS FROM THE 40KM RUC DEPICT NEARLY SATURATED CONDITIONS BETWEEN 7-9KFT...AND EVEN IF BREAKS OCCUR SHARP INVERSION AT H95 TO GENERATE IFR CIGS. AT THIS POINT WILL UPDATE FORECAST TO INCLUDE VARIABLE CLOUDS AND BUMP TEMPS UP. REST ON TRACK. 99 ******************************************************************** 252 PM EDT MON MAY 26 2003 TONIGHT AND TUESDAY... MODELS IN GOOD AGREEMENT IN KEEPING SHORT WAVE CURRENTLY DROPPING ACROSS THE MID MISSISSIPPI VALLEY SOUTH OF OUR CWA LATE TONIGHT AND TUESDAY. HOWEVER...MAIN SOUTHEASTERN CANADIAN VORTEX DIVES SOUTH BEHIND THIS SHORT WAVE OVER THE OHIO VALLEY ON TUESDAY. THERE WILL BE QUITE SOME COLD AIR ALOFT AND SOME MOISTURE AVAILABLE FOR MAINLY AFTERNOON SCATTERED SHOWERS AND THUNDERSTORMS. EXPECT ENOUGH CLEARING TONIGHT FOR SOME FOG IN FAVORED AREAS...THEN FOR SOME HEATING ON TUESDAY TO DESTABILIZE FOR AFTERNOON CONVECTION. GUIDANCE TEMPERATURES VERY CLOSE AND LOOK REASONABLE. TUESDAY NIGHT THROUGH THURSDAY NIGHT... OHIO VALLEY SHORT WAVE EXITS FIRST THING TUESDAY EVENING...JUST AS MAIN UPPER LOW OVER LAKES SETTLES SOUTHWARD INTO AREA. THIS UPPER LOW EXITS WEDNESDAY...ITS PASSAGE DURING WRONG TIME OF DAY W/R THUNDERSTORMS BUT WILL KEEP EASTERN ZONES WEDNESDAY AFTERNOON. NEXT SYSTEM APPEARS QUICKER STILL AND WILL INTRODUCE POPS BY THURSDAY MORNING...UP TO 50 PERCENT WEST BY THEN. FRONT PLOWS THROUGH EARLY THURSDAY WITH GENEROUS WRAP AROUND OVER ABOUT ALL OF AREA BY THURSDAY AFTERNOON GIVEN SOUTHERN TRACK OF SYSTEM. COULD SEE A MORE NORTHERN TRACK RESULTING IN MORE OF A DRY SLOT AROUND MIDDAY THURSDAY BUT TOO FAST/NARROW OF A FEATURE TO RESOLVE AT THIS DISTANCE. THUNDERSTORMS WITH FRONT BASED ON STRENGTH OF UPPER DYNAMICS BUT TIME OF DAY COULD PRECLUDE SEVERE. STRONG WINDS BEHIND FRONT WITH GOOD GRADIENT AND ALIGNMENT IN THE VERTICAL. SHOWER CHANCE WELL INTO THURSDAY NIGHT ON THIS STRONG WRAP AROUND FLOW. NO LARGE DEVIATIONS FROM MOS. FRIDAY THROUGH SUNDAY... MODELS IN REASONABLE AGREEMENT WITH PATTERN THROUGH EXTENDED. SHOULD SEE A DRY DAY ON FRIDAY AS AREA FALLS UNDER UPPER RIDGE ON HEELS OF EXITING SYSTEM. COLD FRONT TO PASS THROUGH REGION ON SATURDAY BRINGING CHANCE OF SHOWERS AND THUNDERSTORMS AS UPPER LOW DIGS INTO GREAT LAKES REGION ONCE AGAIN. UPPER LOW SPINS OVER LAKES INTO MONDAY AND CWA IS ON SOUTHERN PERIPHERY. HAVE PLAYED DRY FORECAST SUN/MON AS THERE IS LITTLE FORCING WITH UPPER LOW AND UNCERTAINTY AS TO WHAT MOISTURE WILL BE AVAILABLE. HAVE PLAYED MORE CLOUDS AND COOLER TEMPS AS A RESULT. JMV/TRM/HC ******************************************************************** 1030 AM EDT MON MAY 26 2003 UPDATED FORECAST THIS AFTERNOON TO KEEP LOTS OF CLOUDS MOST AREAS AND THUS LOWER MAXES A BIT. 12Z SOUNDINGS FROM ILN AND PIT SHOW LOTS OF LINGERING LOW LEVEL MOISTURE. ANY HEATING THAT OCCURS SHOULD ALLOW CLOUDS TO QUICKLY FILL BACK IN UNDER DECENT TEMPERATURE INVERSION AS SHOWN ON ILN SOUNDING AND FORECAST MESOETA SOUNDINGS. WILL ALSO KEEP SPRINKLES IN CENTRAL AND NORTHERN MOUNTAINS OF WEST VIRGINIA. JMV ******************************************************************** wv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 216 PM EDT TUE MAY 27 2003 ISO-SCT TSRA HAVE DEVELOPED EARLY THIS AFTERNOON JUST AHEAD OF MID- LEVEL WAVE OVER SRN IND AND WITHIN REGION OF HIGH 850-500MB LAPSE RATES ASSOC WITH MID-LEVEL TROF, PER RUC ANALYSIS. FREEZING LEVELS ARE LOW, 7KFT FROM 12Z KILN RAOB, SO HAIL IS A POSSIBILITY. PER 12Z LMK-MM5 QPF, ACTIVITY LOOKS TO WANE EARLY THIS EVENING, WITH CHCS FOR PCPN PERHAPS LASTING LONGER INTO THE NIGHT AROUND THE KLEX VICINITY, WHERE 250MB JET STREAK ROUNDS WRN SIDE OF 500MB LOW LIKELY PRODUCING SOME ADDTL LIFT. ETA HINTING AT SOME SCT-BKN CLOUDS ~5KFT THIS EVE OVER NRN PARTS OF LMK FA, BUT WILL TREND TOWARDS M/CLEAR SKIES AFTER MIDNIGHT. SOME GUIDANCE INDICATES LIGHT FOG BY AROUND SUNRISE. REASONABLY DEEP CONVECTIVE PBL TODAY SHOULD ACT TO COUNTER ANY ADDED MOISTURE PROVIDED BY AFTERNOON TSRA, AND WINDS NEAR TOP OF LATE NIGHT NOCTURNAL BL SEEM A BIT PROHIBITIVE, PER ETA, SO MAY HOLD OFF ADDING ANY FOG FOR NOW. SOME SHALLOW GROUND FOG OR HAZY IS CERTAINLY POSSIBLE IN AREAS THAT SEE RAIN TODAY. INTO WED, AS WRN CONUS RIDGE BUILDS, 500MB WAVE NOW OVER SRN SASKATCHEWAN, DROPS QUICKLY SEWD TOWARDS LMK FA BY LATE AFTERNOON. TRENDS IN MOS AND ENSEMBLE POPS FOR WED AFTERNOON HAVE BEEN TOWARDS HIGHER TSRA CHCS, AS UPPER-LEVEL DIVERGENCE INCR WITHIN SOMEWHAT MOIST AND UNSTABLE AIRMASS OVER LMK FA. TEMPERATURE MAXIMA, ESP OVER SRN KY WHERE MORE SUNSHINE IS EXPECTED, SHOULD WARM POSSIBLY TO NEAR 80. INTO WED NIGHT, PCPN CONTINUES TO LOOK LIKELY WITH AVERAGE QPF AMTS FROM 0.5 TO 1.0". AXIS OF MAX QPF PER ETA-ENSEMBLES HAS BEEN TRENDING NEWD OVER PAST COUPLE OF RUNS, SO MAY GO WITH HIGHER POPS IN NERN 2/3 OF FA COMPARED TO THE SWRN 1/3. 6KM SHEAR PROFILES FROM ETA/GFS AT KSDF SUGGESTS SOME STORM ORGANIZATION POTENTIAL, AND WITH DAY 2 SLIGHT RISK NOW OVER ALL OF FA, WILL HAVE TO WATCH SVR POTENTIAL WED AFT/EVE. GFS, AND TO A LESSER EXTENT ETA, SUGGEST SOME POST-SYSTEM BKN-OVC LOW CLOUDS FOR THU. RESIDUAL SHRA SEEM REASONABLE FOR ERN PARTS OF FA, AND WILL ALLOW FOR PARTIAL CLEARING IN KSDF/SRN IN AREAS THU AFTERNOON. AHEAD OF NEXT WAVE RIDING DOWN IN NWLY FLOW ALOFT FRI-SAT, WILL INCR FRI POPS IN GRIDS SLIGHTLY TO ACCOUNT FOR WETTER 12Z GFS SOLN COMPARED TO 6Z RUN. BEST BET FOR PCPN LOOKS TO BE FRI NIGHT. TSRA FCST FOR SAT, BUT NEW GFS SOLN IS FASTER THAN PREV, SO ACTIVITY MAY BE WANING ON SAT. PER 12Z GFS 1KM SRH VALUES, IN THIS NWLY FLOW SITUATION WHERE THE SFC FLOW IS BACKED SOMEWHAT, SVR TS AGAIN POSSIBLE FRI NIGHT. NEGATIVE 500MB HEIGHT ANOMALY PERSISTS INTO EARLY NEXT WEEK, LEADING TO BELOW NORMAL TEMPERATURES. .LMK...NONE. XXV ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE AMARILLO TX 248 PM CDT TUE MAY 27 2003 SATELLITE DATA AND LATEST RUC MODEL SHOWS A BROAD HIGH PRESSURE SYSTEM WITH NEARLY CLEAR SKIES BUILDING OVER THE SOUTHWEST US. FEW LIGHTING STRIKES ASSOCIATED WITH MOUNTAIN CONVECTION NOTED JUST WEST OF THE I-25 CORRIDOR OF NEW MEXICO BETWEEN LAS VEGAS AND RATON. WILL HOLD ON TO SLIGHT CHANCE POPS TONIGHT OVER FAR WESTERN ZONES. SIGNIFICANT NORTHERN STREAM SHORTWAVE WILL PUSH ACROSS THE NORTHERN PLAINS TONIGHT AND HELP PUSH A VERY WEAK COLD FRONT ACROSS THE PANHANDLES ON WEDNESDAY. COULD BE ENOUGH FORCING WITH THIS FEATURE TOMORROW AFTERNOON FOR ISOLATED DIURNAL CONVECTION OVER THE PANHANDLES. SUBSIDENCE ASSOCIATED WITH STRONG RIDGE LOOKS TO KEEP CONVECTION SUPPRESSED ON THURSDAY. NEXT NORTHERN STREAM SHORTWAVE WILL PUSH THROUGH THE CENTRAL ROCKIES THURSDAY NIGHT WITH A STRONGER COLD FRONT REACHING THE PANHANDLES FRIDAY NIGHT. HAVE ADDED 20 PERCENTERS TO THE FRIDAY AFTERNOON PERIOD OVER THE NORTHERN ZONES. STRONG INSOLATION COUPLED WITH LOW LEVEL FORCING SOUTH OF THE FRONT MAY BE SUFFICIENT TO ALLOW A FEW STORMS TO DEVELOP. POPS MAY NEED TO BE EXTENDED SOUTHWARD BUT LATER SHIFTS CAN DECIDE THIS. INHERITED COOLER TEMPS SATURDAY AND SUNDAY STILL LOOK GOOD WITH DECENT SURGE OF COOL HIGH PRESSURE SPREADING OVER THE SOUTHERN HIGH PLAINS THIS WEEKEND. HAVE ADDED 20 PERCENTERS TO THE TUESDAY FORECAST AS WELL. FCSTID = SLATTERY AMARILLO 57 85 60 90 / 10 20 20 10 BEAVER 57 84 60 90 / 10 20 10 00 BOISE CITY 52 84 57 89 / 20 20 20 00 BORGER 59 86 62 93 / 10 20 20 10 BOYS RANCH 56 84 61 94 / 20 20 20 10 CANYON 56 86 60 91 / 10 20 20 10 CLARENDON 59 86 64 90 / 10 20 20 10 DALHART 55 85 58 93 / 20 20 20 00 GUYMON 56 85 59 93 / 10 20 10 00 HEREFORD 56 85 62 89 / 10 20 20 10 LIPSCOMB 58 84 62 91 / 10 20 10 00 PAMPA 59 86 62 92 / 10 20 20 10 SHAMROCK 58 86 64 93 / 10 20 20 00 WELLINGTON 59 87 64 92 / 10 20 20 10 .AMA... TX...NONE. OK...NONE. $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 400 PM EDT TUE MAY 27 2003 ******************************************************************** 400 PM EDT TUE MAY 27 2003 TONIGHT AND TOMORROW... AFTERNOON HEATING KEEPS SOME INSTABILITY AROUND EARLY THIS EVENING. A VORTICITY LOBE THEN PROVIDES CHANCES TONIGHT. ETA IS A BIT SLOWER WITH THIS LOBE AND WOULD LINGER SOME PRECIPITATION IN THE MORNING. BELIEVE IT WILL ME DRY IN THE MORNING...BUT WILL LEAVE SLIGHT CHANCE DUE TO ETA. MODELS THEN SHOW MORE INSTABILITY FOR WEDNESDAY AFTERNOON. WEDNESDAY NIGHT THROUGH FRIDAY NIGHT... FASTER TIMING INDICATED ON SYSTEM MOVING THROUGH THE AREA WEDNESDAY NIGHT AND THURSDAY. RLX-CENTRIC SYSTEM ALSO LOOKS A BIT MORE VIGOROUS AND MOISTURE LADEN. HASTENED INCREASE IN POPS WEDNESDAY NIGHT...RAISING TO LIKELY LATE WEDNESDAY NIGHT INTO THURSDAY. LOOKS LIKE EARLY FRONTAL PASSAGE BUT STRENGTH OF SYSTEM WARRANTS LATE NIGHT-MORNING THUNDERSTORMS. MARGINAL INSTABILITY WITH LAGGING LOW HEIGHTS/TEMPERATURES SUGGEST NOT CUTTING OFF THUNDERSTORM UNTIL THURSDAY NIGHT. DRY DAY FRIDAY...10-12C H85 TEMPERATURES SHOULD SUPPORT ONGOING HIGHS...WELL INTO THE 70S...NICE DAY. KEPT FRIDAY NIGHT DRY PENDING LATER RUNS. IF THEY CONTINUE TO SUPPORT FASTER TIMING...WE COULD SEE PRECIPITATION BY DAWN SATURDAY. SATURDAY THROUGH TUESDAY... MODELS CONTINUE TO SHOW ONLY 1 WEATHER MAKER IN THE DAY 4 THROUGH 7 PERIOD AS A COLD FRONT WITH A STRONG UPPER LOW DIG ACROSS THE GREAT LAKES AND OHIO VALLEY. THE 00Z RUN OF THE GFS ALONG WITH THE CANADIAN BRING THE FEATURE THROUGH THE REGION AROUND 00Z SUNDAY...AND THIS TIMING WAS GENERALLY ACCEPTED. HOWEVER...THE NEW 12Z GFS IS FASTER AND STRONG LIKE ITS PREDECESSOR...THE 6Z GFS. WILL NEED TO MONITOR THIS CHANGE TO SEE IF IT CONTINUES IN SUBSEQUENT RUNS. WITH THE PREVIOUS CLOSED LOW LAST WEEK...THE MODELS WERE INDICATING A VERY VIGOROUS SYSTEM...BUT IN REALITY NOT MUCH HAPPENED. WILL HAVE TO WAIT AND SEE IF THE MODELS END UP BACKING OFF AGAIN. FOR THE REMAINDER OF THE WEEKEND...CONTINUED WITH THE IDEA OF THE MAIN UPPER LOW TO THE NORTH OF THE REGION WITH THE DRY SLOT PUSHING ACROSS THE SOUTHERN PORTION OF THE REGION. THUS HAVE PLAYED LESS CLOUDS OVER TIME FOR THE REMAINDER OF THE PERIOD. CLOUDS MAY BEGIN TO INCREASE AGAIN LATE ON TUESDAY AS A WARM FRONT BEGINS TO APPROACH. FOR TEMPERATURES...HAVE GENERALLY GONE BELOW MOS BY A FEW DEGREES AS WITH THE UPPER LOW IN PLACE...SOME VERY CHILLY 850 AIR IS FORECAST TO MOVE IN. WHILE THE MODEL TENDS TO OVER DO THE STRENGTH OF THE AIR SOME...850 TEMPS MAKE IT HARD TO SUPPORT READINGS SUNDAY AND MONDAY AT GUIDANCE LEVELS. THUS HAVE CUT TEMPS A FEW DEGREES UNDER GUIDANCE SUNDAY THROUGH TUESDAY FOR MAXIMUM TEMPS AND...AS SUNDAY AND MONDAY NIGHTS LOOK TO BE GOOD RADIATIVE NIGHT...HAVE GONE COOLER THERE AS WELL. .RLX... WV...NONE. OH...NONE. VA...NONE. KY...NONE. RPY/TRM/ESS ******************************************************************** 1050 AM EDT TUE MAY 27 2003 RADAR AND SATELLITE SHOW WAVE MOVING FROM OH INTO WV. WILL UPDATE FORECAST TO UP POPS IN AREAS IN FRONT OF THE WAVE. RPY ******************************************************************** 240 AM EDT TUE MAY 27 2003 ...TODAY AND TONIGHT... PESKY UPPER LEVEL LOW WILL BEGIN A SLOW DIVE SOUTHWARD TOWARD THE REGION. WILL KEEP MENTION OF DAYTIME SHOWERS AND THUNDERSTORMS IN THE FORECAST AREA. DUE TO LIGHT LOW LEVEL WINDS...ANY THUNDERSTORMS THAT DO DEVELOP COULD BE SLOW MOVERS. NOT MANY CHANGES NEEDED IN THE FIRST 24 HOURS. ...WEDNESDAY THROUGH MONDAY... THE UPPER LOW WILL MOVE ACROSS THE FORECAST AREA WHICH WILL COMBINE WITH A VORTMAX. THE VORTMAX WILL EXIT THE EASTERN PORTION OF THE AREA WHILE ANOTHER VORTMAX AND UPPER LEVEL TROF MOVES ACROSS THE REGION THROUGH THURSDAY. THE CHANCE OF SHOWERS AND THUNDERSTORMS ARE REASONABLE. NORTHWEST FLOW AND DRIER AIR WILL FILTER INTO THE AREA ON FRIDAY. A SURFACE FRONT WILL MOVE INTO THE FORECAST AREA BY SATURDAY...CONTINUE THE CHANCE OF SHOWERS AND THUNDERSTORMS. THE FRONT WILL BE EAST OF THE FORECAST AREA BY SUNDAY...AS HIGH PRESSURE BUILD INTO THE REGION. THE DRY FORECAST SEEM REASONABLE FOR SUNDAY AND MONDAY. THE TEMPERATURES ARE IN THE BALLPARK. KF/ELW ******************************************************************** 940 PM EDT MON MAY 26 2003 AGAIN DEBATE CONTINUES WHETHER OR NOT CLOUDS BREAK UP. PLENTY OF MOISTURE IN THE LOWEST 8KFT AND NOT MUCH WAA AS LIGHT NORTHERLY WINDS PERSIST. OVC CONDITIONS OVER THE COAL FIELDS HANGING TUFF. LATEST FCST SOUNDINGS FROM THE 40KM RUC DEPICT NEARLY SATURATED CONDITIONS BETWEEN 7-9KFT...AND EVEN IF BREAKS OCCUR SHARP INVERSION AT H95 TO GENERATE IFR CIGS. AT THIS POINT WILL UPDATE FORECAST TO INCLUDE VARIABLE CLOUDS AND BUMP TEMPS UP. REST ON TRACK. FWM ******************************************************************** wv