AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE LITTLE ROCK AR 930 PM CDT FRI APR 26 2002 LAST BATCH OF LIGHT RAIN MOVING ACRS CNTRL AR ATTM. LATEST RUC DATA SHOWING A WEAK SHORTWAVE APCHG FROM THE WEST AIDING IN THE RAINFALL. DO EXPECT THIS RAIN TO TRACK OFF TO THE EAST LATER THIS EVENING... WHICH FOLLOWS CURRENT FCST TRENDS. TEMPS HAVE BEEN HOLDING STEADY FOR MUCH OF THE EVENING AND WILL REWORD UPDATES TO ACCOUNT FOR THIS TREND. REMAINING DATA FROM THE RUC AND LATEST MESOETA STILL SHOWING ADDITIONAL CONVECTIVE DEVELOPMENT MAINLY TO THE NW OF THE FA LATER TONIGHT. THIS IS THE REGION WHERE H85 LOW LVL JET IS FCST TO ALIGN ITSELF AS UPPER SYSTEM BEGINS TO HEAD OUT OF THE ROCKIES. WILL PROBABLY LEAVE SMALL POPS IN FOR MOST AREAS TNGT. STILL EXPECT UPPER TROF TO AFFECT THE FA LATE IN THE DAY SATURDAY. CAP MAY STILL PRECLUDE ANY CONVECTIVE FORMATION OVER THE REGION... BUT STILL CANNOT RULE OUT SOMETHING. LOW POPS STILL LOOK GOOD. NO OTHER CHANGES TO FCST. UPDATES WILL BE OUT SHORTLY. ..44.. .LZK...NONE. ar AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1045 PM EDT FRI APR 26 2002 MAIN UPDATE CONCERN IS TEMPS. WV LOOP AND RUC ANALYSIS SHOWS UPR RDG OVR THE CNTRL CONUS WITH A POTENT SHRTWV TROF MOVG THRU SW STATES. WAA CLOUDS AHD OF DVLPG SFC LOW OVR THE RCKYS STREAMING INTO NRN PLAINS IN ZONAL WLY FLOW ALF. THIS CLD COVER WILL GRADUALLY WORK OVR UPR MI OVRNGT. HWVR...VERY DRY AIR IN PLACE UNDER RDG PER 00Z GRB AND APX SNDGS WILL...AT LEAST INITIALLY...ACT TO THIN MID AND HIGH CLDS AS THEY MOVE IN FM WEST. AS SHRTWV CONTINUES TO LIFT NEWD OUT OF SW STATES OVRNGT BELIEVE WAA MID LVL CLDS WL THICKEN OVR FA PER ETA FCST SNDGS. BIG QUESTION OVRNGT WILL BE AFFECT OF CLD CVR ON MIN TEMPS. WINDS WILL BE LGT MOST OF OVRNGT WITH SFC RDG CNTRD OVR AREA AND DWPNTS IN SINGLE DIGITS! OVR W AND SW COUNTIES. GIVEN WL BE A PERIOD INITIALLY OVRNGT WHEN CLD CVR WL BE THIN...EXPECT TEMPS TO FALL A BIT MORE THAN PREV FCST...ESPECIALLY INLAND. HAVE LWRD INLAND TEMPS TO 18 INLAND OVR SRN AND WRN ZONES AND TO 15 INLAND FOR NCNTRL AND ERN ZONES WHERE CLD CVR WILL BE LAST PLACE TO REACH. WL KEEP TEMPS AROUND 27 NEAR GRT LAKES. .MQT...WINTER STORM WATCH MIZ001>007-009>014. VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1000 PM EDT FRI APR 26 2002 ...MINOR CHANGES TO THE LOW TEMPERATURE FORECAST OVERNIGHT... CONCERN FOR OVERNIGHT ARE THE QUESTION OF FROST AND THAT BRINGS INTO QUESTION WHEN THE CLOUDS WILL ACTUALLY MOVE IN. CURRENTLY SKIES ARE CLEAR ACROSS THE CWA. WINDS ARE EITHER CALM OR LIGHT NORTHWEST. THE 850 RIDGE WILL CROSS THE AREA AROUND 06Z. AT THAT POINT WINDS WILL BE CALM ACROSS THE CWA AND SKIES WILL REMAIN CLEAR. CURRENT DEWPOINTS ARE IN THE MID 20S SOUTH TO THE MID TEENS TO NEAR 20 NORTH. THE AREA OF CLOUDINESS AT 01Z WAS NEAR THE MISSISSIPPI RIVER AND THAT MATCHED THE 700 MB 70 PCT AREA ON THE 00Z RUC VERY NICELY. BOTH THE AWIPS TIMING TOOL AND THE RUC SUGGEST THOSE CLOUDS WILL SPREAD IN AFTER 07Z AND NOT COVER THE CWA UNTIL 12Z. THAT WILL ALLOW MOST LOCATIONS TO GET BELOW FREEZING TONIGHT. ALREADY MANY AREAS IN OUR NRN CWA ARE CLOSE TO FREEZING. SO... THE INCREASING CLOUDINESS PART OF THE FORECAST IS FINE. I WILL LOWER THE LOWS TO 25 TO 30 NORTH GO FOR 27 TO 32 OVER THE SOUTHERN CWA. I WILL INCREASE THE RISK OF FROST OF CONDITIONAL ACROSS THE CWA. WITH LOWS AT OR BELOW FREEZING AND LIGHT WINDS... HARD TO SEE WHY THERE WOULD NOT BE AT LEAST SOME FROST. .GRR...NONE. WDM mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE NORMAN OK 610 PM CDT FRI APR 26 2002 LATEST RUC/MESOETA FORECAST SOUNDINGS SHOW THE AREA IS LARGELY INFLUENCED BY A 250 MB DEEP STABLE LAYER IN CONTACT WITH THE GROUND WHICH IS CAPPED AT THE MOMENT. EXPECT THICK CLOUDS AND PERIODS OF DRIZZLE TO BE THE MAIN WEATHER THIS EVENING. 18Z MESOETA INDICATES INCREASING ASCENT DEVELOPING ACROSS NORTHWEST OKLAHOMA BETWEEN 03-06Z WITH HIGH BASED CONVECTION POSSIBLE BY THIS TIME. ASSOCIATED SHORTWAVE TROUGH EXPECTED TO IMPACT THE REMAINDER OF THE FORECAST AREA AFTER MIDNIGHT. ZONES AND HWO WILL BE UPDATED SHORTLY TO EMPHASIZE DELAYED TIMING OF PRECIPITATION OVERNIGHT. .OUN... OK...NONE. TX...NONE. JAMES ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 958 PM EDT FRI APR 26 2002 PRECIP ASSOCIATED WITH DIVERGENCE INDUCED BY RIGHT ENTRANCE REGION OF UPPER JET/WEAK SHORT WAVE MOVING OUT OF CWFA ATTM. 00Z H3/H5 CHARTS SHOW THIS WELL. H85 CHART SHOWS DRY AIR STILL IN PLACE...BUT QUITE A GRADIENT WITH GSO DRY AND FFC VERY MOIST. SFC DEW POINTS HAVE INCREASED AS WELL...XCPT MUCH MORE SLOWLY NRN TIER. WILL BE IN AN ISENTROPIC LIFT/RH MIN UNTIL LATE TONIGHT. RUC/18Z ETA SHOW GOOD LOW LEVEL MOISTURE ADVECTION AND ISENTROPIC LIFT GETTING GOING BY 09Z. WILL LOWER POPS WHERE CURRENTLY LIKELY AND TRY TO WORD PRECIP TOWARD MORNING. WILL LEAVE SPRINKLES AS IS SINCE PRECIP COULD MOVE IN BEFORE DAYBREAK...BUT ATMOS WILL BE LAST TO MOISTEN. TEMPS LOOK GOOD AND EXPECT NO CHANGES. .GSP... GA...NONE. NC...NONE. SC...NONE. RWH sc AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 845 PM MDT FRI APR 26 2002 CURRENT SURFACE MAP SHOWS LOW PRESSURE MOVING ACROSS THE CENTRAL ROCKIES. STRONG SOUTHEASTERLY FLOW ACROSS MUCH OF CWA. PROBLEM CONTINUES TO REVOLVE AROUND PRECIPITATION TYPE OVERNIGHT. SURFACE DEWPOINTS INTO THE 40S ACROSS SOUTHERN PART OF CWA...WITH DEWPOINTS AROUND 32F ACROSS NORTHEAST WYOMING AND NORTHWEST SOUTH DAKOTA. DRY AIR OVER NORTH DAKOTA HAS BECOME MORE MOIST AS SNOW FALLING IN AREA OF WARM ADVECTION. 00Z RUC/ETA CONTINUE THE TREND OF THE 18Z MODELS IN KEEPING 850MB TEMPERATURES OF +2C TO +4C SOUTH OF I-90 OVERNIGHT. 00Z KUNR SOUNDING HAD FREEZING LEVEL ABOUT 1000FT HIGHER THAN THE 18Z ETA/AVN. 00Z ETA INITIALIZED ABOUT 3C AT 850 FOR RAPID CITY. THROUGH THE NIGHT...FREEZING LEVEL/WET BULB ZERO STAYS AROUND 7000-8000FT MSL. AT THIS TIME...ONLY REAL THREAT FOR SNOW REMAINS IN THE BLACK HILLS AND NORTHEAST WYOMING LATE TONIGHT AND SATURDAY. LACK OF DRY AIR AND VERY MOIST LOW LEVEL AIR ADVECTING INTO THE AREA...WILL BE HARD FOR EVAPORATIVE COOLING TO CHANGE RAIN OVER TO SNOW ON THE PLAINS EAST OF BLACK HILLS. BY THE TIME IT DOES CHANGE OVER TO SNOW AROUND RAPID CITY...BULK OF PRECIPITATION IS FORECAST TO BE OVER. WILL UPDATE FORECAST...AND CUT BACK ON SNOW AMOUNTS...ESPECIALLY OVER THE PLAINS. ADJUSTMENTS MADE TO TEMPERATURES AND WINDS TOO. .UNR...NONE. 07 sd DEEP SOUTH TEXAS FORECAST DISCUSSION...COR TO CCF NATIONAL WEATHER SERVICE BROWNSVILLE TX 310 PM CDT FRI APR 26 2002 SHORT TERM...QUITE A BIT OF CLOUD COVER OVER NORTH TEXAS THIS AFTERNOON AS MSAS SURFACE ANALYSIS INDICATES A BOUNDARY DRAPED OVER CENTRAL TX. CONVECTION HAS BEEN LIMITED BY CLOUD COVER OVER NORTH TX WITH CAPPED ATMOSPHERE OVER SOUTH TX. 500MB SHORTWAVE TROUGH OVER SOUTHERN CA PROGGED TO MOVE INTO SOUTHWEST U.S. TONIGHT AS LOW PRESSURE DEVELOPS OVER THE ROCKIES. THIS SYSTEM TO MOVE INTO THE CENTRAL PLAINS SATURDAY BRINGING SURFACE TROUGH/PACIFIC FRONT INTO CENTRAL TX AS THE STALLED BOUNDARY ACROSS CENTRAL TX RETREATS NORTHWARD AS A WARM FRONT. WITH THE SHORTWAVE TROUGH LIFTING OUT OF THE PLAINS SATURDAY...ZONAL FLOW ACROSS SOUTHERN TIER TO KEEP SURFACE TROUGH/STATIONARY BOUNDARY ACROSS NORTH CENTRAL TX THROUGH SUNDAY. REMOTE POSSIBILITY OF AN ISOLATED SHOWER OR THUNDERSTORM DEVELOPING ACROSS WESTERN PORTIONS OF CWA TONIGHT INTO EARLY SAT IF CONVECTION DEVELOPS ACROSS SOUTHWEST TX BUT NOT LIKELY TO REACH CWA ANYWAY. OTHERWISE...DRY AND WARM CONDITIONS TO PERSIST WITH 500MB SUBTROPICAL RIDGE OVER THE WESTERN GULF OF MEXICO. EXTENDED...MORE OF THE SAME THROUGH WEDNESDAY WITH 500MB RIDGE OVER NORTHEAST MEXICO AND WESTERN GULF NOT PROGGED TO MOVE MUCH THROUGH WEDNESDAY. LOW PRESSURE OVER THE CENTRAL AND SOUTHERN PLAINS TO INCREASE PRESSURE GRADIENT OVER SOUTH TX PROVIDING BREEZY CONDITIONS TUESDAY INTO WEDNESDAY. MARINE...WV AND IR SATL IMAGERY INDICATES THAT THE CA CLOSED LOW IS PROGRESSING EASTWARD INTO THE DESERT SW AS THE 5H KICKER MOVES SOUTH ACROSS THE PACIFIC NW. THE LATEST RUC DATA SHOWS A WELL DEFINED SURFACE LOW CENTERED OVER COLORADO RESULTING IN A TIGHTENING PGF OVER THE SOUTHERN PLAINS STATES. WILL KEEP THE SCA IN PLACE OVER THE BAY WATERS THIS EVENING...ALTHOUGH THE SURFACE WINDS MAY DIMINISH BELOW SCA LEVELS AS THE SURFACE WINDS DECOUPLE AFTER SUNSET. OFFSHORE... CONDITIONS WILL PUSH PAST SCA LEVELS LATE TONIGHT OR EARLY SAT AS THE PGF CONTINUES TO TIGHTEN. CONDITIONS SHOULD RELAX SOMEWHAT AS THE CA 5H LOW IS QUICKLY INGESTED INTO THE FAST MOVING NORTHERN STREAM OVER THE LOWER 48 STATES. THE 5H KICKER WILL CONTINUE TO MOVE SOUTHEAST OVER THE WESTERN PORTIONS OF THE COUNTRY RESULTING IN ANOTHER CENTRAL PLAINS SURFACE LOW AROUND WED OF NEXT WEEK. THIS WILL LIKELY REQUIRE ANOTHER ROUND OF SCA FOR THE LOWER TX COAST. BRO NU 075/090 076/091 076 00/00/00/00/00 HRL NU 074/093 075/094 075 00/00/00/00/00 MFE NU 075/094 076/095 076 05/05/00/00/00 RGC NU 073/095 074/096 074 05/05/00/00/00 SPI NU 076/085 076/085 076 00/00/00/00/00 SYNOPTIC-PUBLIC...CASTILLO.61 AVIATION-MARINE-MESO...SPEECE.60 INTERNET ADDRESS...WWW.SRH.NOAA.GOV/BRO .BRO...SCA TONIGHT FOR GMZ130-150-155-170-175. tx COASTAL BEND FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 1015 AM CDT FRI APR 26 2002 WEAK 500HPA SHORTWAVE TRIGGERING -SHRA ACROSS THE NORTHERN CWA AND POINTS NORTH BENEATH A HIGH BASED CAPPING INVERSION. COLD FRONTAL BOUNDARY LURKING NORTH OF THE CWA WILL RETREAT NORTHWARD THIS AFTERNOON. 15Z VISIBLE SATELLITE IMAGERY INDICATES A SOUTHWARD MOVING BOUNDARY(NOT SURFACED-BASED) FROM KHYI-KSGR WHICH MAY ACT IN CONCERT WITH THE AFOREMENTIONED SHORTWAVE TO SUSTAIN/DEVELOP CONVECTION. STILL ANTICIPATE THESE FEATURES WILL EXIT THE AREA BY AFTERNOON AND NO POPS WILL BE NEEDED. 1000-850HPA THICKNESS/850HPA TEMPERATURES ARE EXPECTED TO BE HIGHER THIS AFTERNOON...BUT ENOUGH CLOUDINESS WILL LINGER WITH 1.5" PWATS AND FORCING FROM SEABREEZE BOUNDARY SO NO CHANGES TO TEMPERATURES. SIERRA MADRE THERMAL CYCLONE AND TIGHTNING PRESSURE GRADIENT SUPPORTS CURRENT WIND FORECAST. MARINE...EARLY MORNING FORECAST LOOKS ON TARGET AS QUICK LOOK AT NEW RUC SHOWS SFC GRADIENT TIGHTENING THIS AFTERNOON AND SOMEWHAT STRONGER WINDS ABV SFC BEGIN TO MIX DOWNWARD. .CRP...SCA GMZ230-235. 85/PUBLIC 70/MARINE-AVIATION tx DEEP SOUTH TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 940 AM CDT FRI APR 26 2002 SHORT TERM...LOW LEVEL GULF MOISTURE EVIDENT ON THE 12Z BRO SOUNDING WILL ALLOW THE SCT SC FIELDS TO PERSIST THROUGHOUT THE DAY. THE CURRENT RUC DATA MAINTAINS THE BROAD RIDGING THROUGHOUT THE DAY AND THIS SHOULD PUSH AFTERNOON HIGH TEMPS TO NEAR OR ABOVE NUMERICAL GUIDANCE. THE RUC MSL FIELDS STEADY TIGHTEN THROUGH MIDDAY WHICH WILL INCREASE THE SURFACE GRADIENT OVER THE AREA. SURFACE WINDS SHOULD REMAIN BELOW WIND ADVISORY CRIT. CURRENT ZFP LOOKS GOOD. MARINE...GRADIENT FLOW OVER THE MARINE AREAS WILL INCREASE TO NEAR SCA LEVELS ACROSS THE BAY WATERS LATER TODAY AND WILL APPROACH SCA LEVELS OFFSHORE LATER TONIGHT. THIS TREND IS WELL-REFLECTED IN THE CURRENT CWF AND NO CHANGES REQUIRED ATTM. SYNOPTIC-AVIATION-MARINE...60/MESO...VEGA INTERNET ADDRESS...WWW.SRH.NOAA.GOV/BRO .BRO...SCA TODAY FOR GMZ130. tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD, VA 1020 AM EDT FRI APR 26 2002 HI CI TO THE NRN HALF THE CWA THIS AFTN. RUC AND AVN PICK THIS OUT NICELY. BOTH SHOW IT DIMINISHING TOWARD EVNG. WL GO PC N AND MS S WITH LOWER TEMPS N AND RAISE MAXES A LITTLE IN THE S. REMAINDER OF FCST LOOKS GOOD. .AKQ... MD...NONE. NC...NONE. VA...NONE. JAB va AREA FORECAST DISCUSSION...CORRECTION TO LONGER TERM NATIONAL WEATHER SERVICE DES MOINES IA 230 AM CDT SAT APR 27 2002 SHORT TERM... I WILL BEGIN WITH ELEVATED CONVECTIVE THREAT THIS MORNING. FIRST WAVE OF ISENTROPIC LIFT CONTRIBUTED TO MOISTENING FRI EVENING, BUT ONLY A FEW SPRINKLES IN NORTHERN IA. THIS HAS SINCE SHIFTED NE. WHOLESALE THETA-E ADVECTION IS IN PROGRESS WITH WIDE ZONE OF ELEVATED CONVECTION ON ITS WAY FROM KS/NE. OUN SOUNDING SHOWED CONSIDERABLE ELEVATED CAPE AND MOISTURE AT 850 MB (13C TD). RUC 03Z FORECAST SOUNDINGS SHOW CONSIDERABLE POTENTIAL FOR ELEVATED SEVERE CELLS 15-18Z AS ELEVATED CAPES JUMP OVER 1000 J/KG IN SOUTHERN IA. AMPLE SHEAR SHOULD LEAD TO STRONG UPDRAFTS CAPABLE OF LARGE HAIL, WITH SEVERE THREAT EITHER DIMINISHING OR SHIFTING INTO NORTHERN IA BY EARLY AFTERNOON. NEW CONVECTION IN W TX IS HANDLED BY META/AVN WELL IT APPEARS, TAKING IT RAPIDLY INTO ERN KS AND MO AROUND MIDDAY, AND AFFECTING MAINLY OUR SE CWA. PRONOUNCED DRY SLOT TAKING SHAPE NICELY ON WATER VAPOR IN NM AND EVEN SOMEWHAT INTO WRN KS. THIS SHOULD LEAD TO A BREAK IN PRECIP BY EARLY AFTERNOON, LEAVING CONSIDERABLE LOW CLOUDS. MODELS ARE STILL IN GOOD AGREEMENT, WITH LOW AND TRIPLE POINT TAKING AIM AT SW IA BY 00Z. HOWEVER, ONE COULD ARGUE THAT SURFACE LOW MAY END UP FURTHER N THAN PROGGED GIVEN WHERE THE DRY SLOT IS NOW TAKING SHAPE. CONCERN FOR LOW CLOUDS TO HAMPER DESTABILIZATION EXISTS, BUT CLOUDS ARE RATHER SHALLOW IN SOUTHERN HIGH PLAINS UPSLOPE REGION, WHICH SHOULD ERODE WELL AFTER DRY SLOT MOVES NE AND THOROUGH MIXING ENSUES. 0-3KM SHEAR QUITE IMPRESSIVE, WITH 0-1KM HELCITY ABOVE 150 M2/S2 NEAR TRIPLE POINT. 0-3KM CAPES ARE SUGGESTIVE OF HIGHER TORNADIC POTENTIAL IF STORMS CAN FIRE. EYEBALL VALUES ARE ABOVE 50 J/KG, IF NOT APPROACHING 100-150 J/KG. ALONG WITH VERY LOW LFC/LCL HEIGHTS, I HAVE CONCERNS AS SPC DOES FOR STRONG TORNADOES. META LAST SEVERAL RUNS IS INSISTENT ON DEVELOPING CONVECTION (BASED ON UPPER DIVERGENCE AND QPF CONTOURS) NEAR TRIPLE POINT AND TRAVEL NE ALONG WARM FRONT ALONG AND JUST S OF I-80 CORRIDOR. HIGH END MODERATE RISK IS CERTAINLY ON TARGET, AND WILL HEAVILY WEIGHT THE TORNADO THREAT IN OUR HWO FROM I-80 S. NOT VERY CONCERNED ABOUT FLOOD POTENTIAL GIVEN SPEED OF WHICH RAIN AREA IS MOVING. OUR SOIL CAN TAKE QUITE A BIT OF RAIN RIGHT NOW. CURRENT TEMP/WIND FORECAST LOOKING FINE AS WELL, SO ONLY MINOR ADJUSTMENTS REQUIRED. LONGER TERM... AS SYSTEM DEPARTS, WILL MAINTAIN SHRA CHANCE EARLY SUNDAY IN NORTHERN IA. CLEARING WILL BE SLOW ON SUNDAY, BUT SHOULD CLEAR OUT DURING THE EVENING. FOG THREAT MAY ALSO EXIST AS SURFACE RIDGE PASSES OVER. WILL ALSO ADD CHANCES OF TSRA AS APPEARS A RATHER WET PATTERN TAKING SHAPE THIS WEEK WITH DECENT W-E THERMAL ZONE NEARBY AND WSW UPPER FLOW. BEST SHOT OF TRSA, AND POSSIBLY MCS ACTIVITY GIVEN FAVORABLE LLJ IMPINGEMENT ON BOUNDARY, WOULD BE WEDNESDAY. WILL NOT MAKE MAJOR ADJUSTMENTS BEYOND TUESDAY. .DSM...NONE KULA ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 231 AM CDT SAT APR 27 2002 TIMING ON EXITING PCPN THIS MORNING FOLLOWED BY TEMPERATURES TODAY WILL BE THE MAIN FORECAST CHALLENGE DAYS 1-2... SFC LOW CONTINUES TO DEEPEN THIS MORNING OVER SE COLORADO AS OUR UPPER LVL TROF CROSSES INTO ERN NM. MODELS APPEARING TO HAVE A DECENT HANDLE WITH THIS AND VERIFIED WELL PER PROFILERS WITH A 120KT JET ENTERING THE PANHANDLE OF TX. VICI PROFILERS ALSO SUPPORTING THE LLJ THAT ALL MODELS PROGGED DEVELOPING IN WRN OK/WRN KS EARLY THIS MORNING. THIS CONTINUES TO PLACE WESTERN KANSAS IN THE RIGHT EXIT REGION OF THE 25H JET WITH A LLJ OVER OUR ERN CWA. I295-I305 ALSO SHOWING ISENTROPIC LIFT AND MOISTURE REMAINING IN PLACE EARLY IN THE DAY AS WELL, ESPECIALLY IN THE EAST. ALL THIS SUPPORTS KEEPING A MENTION OF SHRA/TSRA GOING EARLY ACROSS THE CWA EARLY SATURDAY MORNING, ESPECIALLY ACROSS THE ERN 1/2 OF THE CWA. WILL USE RUC AS TIMING IN THE NEAR TERM WHICH PLACES OUR VORT LOBE AROUND EHA BY 12Z AND IN OUR ERN CWA BY 18Z. ALREADY RADAR SHOWING PCPN DEVELOPING IN AND JUST SW OF THE CWA AND AM EXPECTING THIS PCPN TO CONTINUE TO INCREASE IN AREAL COVERAGE THROUGH THE MORNING OUR VORT LOBE APPROACHES. GIVEN TIMING OF VORT LOBE CROSSING WESTERN KS THIS MORNING WILL GO WITH 20 POPS IN THE SW CWA THIS MORNING AND 50 POPS IN THE NORTH AND EAST. AT THIS TIME SEVERE THREAT NOT LOOKING GOOD THIS MORNING FROM THESE ELEVATED TSRA. BEST INSTAB APPEARS TO HOLD OFF UNTIL WELL AFTER PCPN HAS EXITED THE CWA. BY 18Z SKIES SHOULD BE CLEARING FROM WEST TO EAST AS SUBSIDENCE DEVELOPS BEHIND OUR WAVE. TIGHT GRADIENT IN PLACE AT THE SFC AND WITH SOME MIXING LIKELY THE WIND ADV FOR TODAY STILL LOOKS REASONABLE. OUR SFC LOW QUICKLY SHIFTS TO THE EAST DURING THE AFTERNOON ALLOWING THE GRADIENT TO RELAX SOME AS DOWNSLOPE FLOW DEVELOPS IMPROVES. 85H TEMPS RANGING FROM 18C IN THE NE TO 21C IN THE SOUTHWEST. WITH THIS IN MIND BELIEVE CURRENT FORECAST HAS THE RIGHT IDEA WITH MID TO UPPER 70S FOR AFTERNOON HIGHS. A COOL FRONT WILL DROP SOUTH ACROSS THE AREA OVERNIGHT ALLOWING FOR HIGH PRESSURE TO BUILD INTO CNTL KS DURING THE DAY ON SUNDAY. THIS WILL ALLOW FOR THE WINDS GRADUALLY SHIFT TO THE SOUTHEAST DURING THE DAY AS PRESSURES BEGIN TO FALL ALONG THE LEE OF THE ROCKIES. ETA/AVN BOTH SUGGESTING A SE FLOW BY 00Z MON OVER THE LOWEST 2-3KFT, HOWEVER THE NGM TAKES A MORE SW FLOW IN THE LOW LVLS. AT THIS TIME WILL FAVOR THE ETA/AVN GIVEN LEE TROF DEVELOPMENT. THIS DOES NOT SUPPORT FAVORABLE DOWNSLOPE WARMING COMPARED TO SATURDAY SO WILL FOLLOW THE ETA/AVN 85H TEMPS FOR HIGHS ON SUNDAY. DAYS 3-7... THE REMAINDER OF THE FORECAST LOOKS ON TRACK SO NO CHANGES PLANNED IN THE LATER PERIODS. PRELIMINARY GUIDANCE FOR COORDINATION ONLY. OFFICIAL FORECASTS ARE CONTAINED WITHIN THE DODGE CITY ZONE FORECAST. DDC 78 41 71 46 / 30 0 0 0 GCK 77 41 72 43 / 30 0 0 0 EHA 76 45 75 44 / 10 0 0 0 LBL 78 44 73 46 / 20 0 0 0 HYS 75 40 68 44 / 50 0 0 0 P28 79 42 71 51 / 50 0 0 0 .DDC...NONE. FCSTID = 18/02 ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 500 AM EDT SAT APR 27 2002 00Z RAOBS/LATEST WV LOOP AND RUC ANAL SHOW CONFLUENT WNWLY FLOW ALF OVR THE GRT LKS BTWN NRN BRANCH VORTEX OVR HUDSON BAY AND BLDG SRN BRANCH UPR RDG OVR THE GLFMEX. AT THE SFC...1028MB HI PRES OVR CWA THIS MRNG IN SUBSIDING RIGHT EXIT OF 120KT H3 JET MAX AT INL BRINGING TRANQUIL CONDITIONS AND DRY AIR...00Z PW ONLY 0.11 INCH AT INL AND 0.13 INCH AT APX. AIRMASS OVR CWA UNSEASONABLY CHILLY WITH H85 TEMPS ARND -7C. SFC DWPTS GENERALLY IN TEENS AND 20S. SOME LGT SN HAS BKN OUT ACRS NRN PLAINS AS WEAK SHRTWV LIFTING ENE THRU THE NRN PLAINS IN RRQ OF H3 JET MAX INTERACTING WITH MSTR RETURN/WAD ON W SIDE OF GRT LKS RDG AND N OF SHARP SFC-H85 WARM FNT. HI CLD DOWNSTREAM OF THIS AREA OF DISTURBED WX DRIFTING INTO NW GRT LKS. FARTHER UPSTREAM...POTENT NRN BRANCH SHRTWV DROPPING S ALG THE W COAST EJECTING VIGOROUS SHRTWV OVR THE DESERT SW ENE. THIS SYS HAS TAKEN ON A NEGATIVE TILT...AND WV LOOP/RAOBS INDICATE ABUNDANT MSTR FLOWING NE AHD OF SHRTWV AS SWLY H3 WINDS AS HI AS 150KT OVR NRN MEX RETURNING SUBTROPICAL MSTR. 12Z-00Z H3 HGT FALLS OVR 200M NOTED ACRS THE SW WITH THIS SYS...AND PW UP TO 1.5 INCHES HAS MOVED AS FAR N AS OKC...WITH H85 DWPTS AS HI AS 15C IN TX S OF MAIN H85 WARM FNT IN SRN PLAINS. MAIN FCST CONCERNS THIS PACKAGE REVOLVE ARND EVOLUTION/TRACK OF VIGOROUS SHRTWV LIFTING ENE FM THE SRN ROCKIES...SPECIFICALLY PCPN TYPE/AMTS/TIMING AND GOING HEADLINES. WITH VIGOROUS DYNAMICS AND MSTR RETURN OVR COLD DRY AIRMASS IN PLACE OVR GRT LKS...CONDITIONS RIPE FOR A LARGE AMT OF SN SOMEWHERE. 00Z ETA MODEL FCST OF SW SHRTWV REMAINS IN REMARKABLE AGREEMENT WITH PREVIOUS RUNS. 00Z ETA APPEARS TO HAVE GOOD HANDLE ON SEPARATION BTWN PCPN OVR ND AND DVLPG PCPN FARTHER S CLOSER TO MAIN H85 WARM FNT...SO ETA GENERALLY MODEL OF CHOICE. ONLY CONCERN IS THAT H3 JET MAX IN SE QUADRANT/DRY SLOT OF SHRTWV MAY HAVE BEEN INITIALIZED A BIT ON THE LGT SIDE...130KT VS 150KT OBSVD FM ACARS DATA IN NRN MEX. 00Z ANAL ON H5 VORT MAGNITUDE ALSO HIER THAN FCST BY PREVIOUS RUNS. THE IMPLICATION OF THIS ERROR IS THAT STORM TRACK MAY HAVE TO BE ADJUSTED A BIT FARTHER N THAN FCST. FOR FCST DETAILS...ETA SHOWS WEAK SHRTWV/UPR DVGC CAUSING SN IN ND THIS MRNG TENDING TO SHEAR OUT AND WEAKEN AS THESE MECHANISMS RUN INTO UPR CONFLUENCE/DRY AIRMASS IN PLACE TDAY. GIVEN MAGNITUDE OF DRY AIR IN PLACE...THE MAIN IMPACT FM THIS DISTURBANCE WL BE TO THICKEN CLDS W TO E ACRS CWA. MAIN ACTION BEGINS LATER TDAY AS UPR JET FM THE SW LIFTS INTO THE SRN PLAINS DURG THE AFTN AND NRLY COINCIDENT H5 SHRTWV/991MB SFC LO REACHES NR OMA BY 00Z...A FCST CONSISTENT WITH NGM/AVN/CAN MODELS AS H3 JET MAX OVR ONTARIO INCRSES TO 140KT BY 00Z SUN IN TIGHTENING HGT GRADIENT IN ADVANCE OF SHRTWV...ETA SHOWS H4-2 DVGC INCRSG OVR ESPECIALLY THE SRN TIER ZNS. HOWEVER...DIFFLUENT LLVL FLOW REMAINS ESE OUT OF DRY HI TO THE E ALL DAY. SINCE H85 WARM FNT PROGGED TO REACH ONLY IL/WI BORDER BY 00Z WITH TIGHTEST THERMAL PACKING/BEST ISENTROPIC LIFT/H85-7 FRONTGEN FORCG/H7 UVV REMAINING S OF ALL BUT MNM COUNTY...BELIEVE THE ETA AND OTHR MODELS MAY BE TOO AGGRESSIVE AT PUSHING PCPN INTO NRN TIER THIS AFTN WITH LEADING EDGE OF H7 PROGGED TO ARRIVE ONLY TOWARD 00Z. EVEN WITH AN ADJUSTMENT TO THE N OF STORM TRACK...BEST DYNAMICS WL IMPACT ONLY MNM COUNTY. SO WL BE SLOWER THAN MODELS/MOS TO BRING PCPN OVR NRN TIER...AND KEEP PCPN OUT OF ERN ZNS AS IN GOING FCST. BUT CATEGORICAL WORDING FOR WI BORDER SEEMS TO BE IN ORDER. PCPN TYPE THIS AFTN A QUESTION MARK. XPCT INSOLATION THRU INCRSG CLDS TO RAISE TEMPS INTO THE 40S AT MOST PLACES TDAY...WITH WARMEST READINGS OVR THE E WHERE CLD WL BE THINNER LONGER. BUT WITH LO DWPTS IN PLACE...EVAP COOLING SHUD OFFSET THE DIURNAL WRMG TO A CERTAIN EXTENT. ETA FCST SDNGS FOR SRN TIER INDICATE WBLB ABV ZERO THRU LOWEST 1000 FT...PROBABLY ENUF TO ALLOW A MIX WITH RA AT THE ONSET. DEPTH OF ABV 0 WBLB TEMP SHALLOWER FARTHER N...SO ANY PCPN THAT DVLPS HERE SHUD BE ALL SN EVEN AT THE ONSET. XPCT LTL IF ANY SN ACCUMULATION BEFORE SUNSET. ETA AND OTHR MODELS PUSH SFC LO INTO SRN LK MI BY 00Z...WITH TIGHT INCRSGLY CYC FLOW DVLPG ACRS CWA. ETA AND NGM QUITE PROLIFIC GENERATING QPF (ETA FCSTS 1.33 INCHES QPF BY 12Z SUN AT MNM)...BUT A NUMBER OF QUESTION MARKS REMAIN. MOST SGNFTLY...H5 VORT TRACK IS WELL S OF CWA WITH BEST H85 THERMAL PACKING/H85-7 FRONTGEN/H85-5 QVECTOR CNVGC/H100-7 MSTR CNVGC REMAINING MAINLY S OF CWA AS WELL...ONLY MNM COUNTY WITHIN THE MOST SGNFT FORCG. EVEN IF STORM TRACK ADJUSTED N BY 50 MILES...NRN TIER WOULD STILL MISS OUT ON BEST DYNAMICS/MOISTENING. BEST UPR DVGC IN RRQ OF H3 JET MAX IN ONTARIO PULLS E DURG THE OVRNGT AS JET DEPARTS. ISENTROPIC LIFT ON THE 290K TO 295K SFCS DVLPS (H7-75) WITH 3G/KG AVBL OVR THE N...4G/KG OVR THE S...BUT WND SPEEDS OVR THE NRN TIER ONLY 10 TO 15 KTS. ON THE OTHR HAND...INCRSG NE H925 WND UP TO 40KTS FCST BY ETA TNGT WL ENHANCE PCPN RATES OVR NCNTRL HIER TERRAIN...BUT H85 TEMPS FCST ARND -5C WL RESULT IN MINIMAL IF ANY LK ENHANCEMENT (DELTA-T 6-7C BLO 8C THRESHOLD). THE BOTTOM LINE IS THAT LWR AVN QPF PREFERRED FOR CWA TNGT...WITH A MAX ABOUT 0.75 INCHES IN MNM COUNTY. ETA BUFKIT FOR MNM SHOWS ALL SN AT MNM TNGT...BUT AVN MOS INDICATES A MIX WITH RA. FCST H100-85 THKNS IN TOUGH TO CALL 1305M RANGE...SO WL MAINTAIN DAYSHIFT FCST OF MIX OF RA/SN NR LK MI ONCE EVAP COOLING MECHANISM DIMINISHES THIS EVNG. CHCS OF MIX WITH RA WL BE HIER IF STORM TRACK IS A BIT FARTHER N. HAVE OPTED TO UPGRADE WATCH ONLY TO WRNG IN MNM COUNTY...WHERE INTERIOR ZNS HAVE BEST CHC TO PICK UP HVY SN. WL GO WITH ADVYS REST OF ZNS WITH KEWEENAW COUNTY ONLY ODD ZN OUT AND WORD ADVY IN CMX COUNTY FOR THE FAR S. SN WL DIMINISH LATE AT NGT OVR THE W AS AVN/ETA INDICATE H5 SHRTWV AXIS PUSHING E AND DNVA/H85-5 QVECTOR DVGC DVLPG DESPITE LINGERING CYC FLOW. FCST WNDS OVR THE LK MI ZNS UP TO 50KTS AT 2K FT JUSTIFY CONTG WINDY WORDING FOR DELTA/MNM COUNTIES. FCST MINS NR MOS. UPR SHRTWV/SFC LO PULL E ON SUN WITH LINGERING DYNAMICS OUT OF ERN ZNS BY AFTN. ALTHOUGH DEEP MSTR PULLS OUT WITH STORM SYS AND DYNAMICS...LINGERING CYC FLOW PROMISES TO KEEP PLENTY OF CLD ARND ALL DAY. BEST CHC FOR AFTN CLRG OVR THE FAR W...WHERE AVN/ETA SHOW WEAK SFC RDG MOVG OVHD BY LATE IN THE DAY. BUT ETA FCST SDNGS SHOW PLENTY OF LINGERING LLVL MSTR...SO RELUCTANT TO BE TOO AGRESSIVE WITH CLRG. WL TEND TOWARD HIER MAV GUIDANCE OVR THE FAR W WHERE MORE INSOLATION IS PSBL...BUT TEND LWR OVR THE E AND CNTRL TOWARD FWC/ETA BLYR TEMPS. COORDINATED WITH APX/GRB/DLH. .MQT...WINTER STORM WRNG TNGT AND EARLY SUN MIZ012. SN ADVY MIZ001>007-009>011-013-014. KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 125 AM CDT SAT APR 27 2002 FORECAST CHALLENGES -- SEVERE WEATHER POTENTIAL TODAY SYNOPSIS -- LATEST REGIONAL 88D REFLECTIVITY MOSAIC/IR IMAGERY SHOWS INCREASING CONVECTIVE ACTIVITY FROM S-CNTRL NEB TO ERN KS. THESE STORMS ARE FORMING IN A ZONE OF INTENSE WARM ADVECTION/ISENTROPIC LIFT AND ON THE NOSE OF INCREASING 850 MB MOISTURE, PER OUN 27/00Z SOUNDING AND 27/03Z RUCII DATA. AT THE SURFACE, A DEEPENING LOW WAS SITUATED OVER NERN NM AT 06Z, WITH THE PRIMARY WARM FRONT STILL WELL TO OUR S, OVER N-CNTRL TX. FORECAST -- SEVERE WEATHER POTENTIAL IN THE NEXT 2-4 HOURS AND THEN AGAIN THIS AFTERNOON ARE THE MAIN CONCERNS. THE ETA AND AVN ARE NOW IN FAIRLY GOOD AGREEMENT ON THE MASS FIELDS THROUGH THE FIRST 24 HOURS. IN THE SHORT TERM, CONTINUED MOIST/THERMAL ADVECTION IN THE LOW LEVELS WILL INCREASE CHANCES OF ELEVATED SEVERE CONVECTION EARLY THIS MORNING. 27/03Z RUCII FORECAST SOUNDINGS FOR SERN NEB SHOW MUCAPE VALUES INCREASING TO AROUND 1000 J/KG BY 09Z WITH SUFFICIENT SHEAR THROUGH THIS BUOYANT LAYER TO SUPPORT ELEVATED MESOCYCLONES. THEN, ATTENTION TURNS TO THE INTENSE MID-LEVEL SHORTWAVE CURRENTLY OVER NM AS OF 06Z. THIS FEATURE WILL RAPIDLY EJECT NEWD TODAY WITH A POTENT SURFACE CYCLONE MOVING FROM N-CNTRL KS/S-CNTRL NEB INTO SWRN IA BY 28/00Z. THE AMOUNT OF SEVERE WEATHER IN OUR CWA TODAY WILL BE CONTINGENT ON TWO FACTORS: 1) THE AMOUNT OF QUALITY MOISTURE RETURN, AND 2) THE DEGREE OF AIRMASS MODIFICATION AHEAD OF THE SURFACE LOW. 06Z METAR DATA SUGGESTS 1) MAY BE THE MOST PROBLEMATIC AS THE GOOD SURFACE DEWPOINTS (I.E. 55-65) ARE STILL OVER TX. EVEN WITH INTENSE CYCLOGENESIS, THIS MOISTURE WILL LIKELY NOT MAKE IT, ESPECIALLY GIVEN OUR SURFACE TRAJECTORIES (SE). THUS, THE BEST CHANCES FOR 50S DEWPOINTS WILL NOT BE ADVECTIVE, BUT FROM AIRMASS SATURATION DUE TO THE ONGOING CONVECTION. THIS LEADS TO 2). HOW MUCH AIRMASS RECOVERY WILL OCCUR AHEAD OF THE SURFACE LOW? BOTH THE ETA AND AVN INDICATE AN IMPRESSIVE DRY SLOT MOVING INTO SERN NEB/SWRN IA BY 18Z, SO IT APPEARS SOME DESTABILIZATION IS POSSIBLE. GIVEN THE DYNAMICS OF THE SYSTEM, ONLY 500-1000 J/KG WILL LIKELY BE NECESSARY TO INITIATE SURFACE-BASED CONVECTION. LOW LCL HEIGHTS AND HIGH 0-1 KM SRH/SHEAR VALUES NE OF THE SURFACE LOW, SUGGEST GOOD LOW-TOPPED TORNADIC SUPERCELL POTENTIAL *IF* CONVECTION CAN INITIATE IN OUR CWA. WE WILL HIT THIS SCENARIO RATHER HARD ACROSS OUR SERN ZONES IN THE HWO. THIS SYSTEM WILL RAPIDLY MOVE TO THE E TONIGHT, WITH SOME LINGERING PRECIPITATION THIS EVENING. BOTH THE AVN/ECMWF INDICATE THE NEXT CHANCE OF PRECIPITATION WILL OCCUR ALONG AND TO THE N OF A FRONTAL BOUNDARY THAT WILL BE SLOWLY SAGGING THROUGH THE AREA TUESDAY NIGHT/WEDNESDAY. OTHERWISE, GUIDANCE TEMPERATURES LOOKS REASONABLE ON HIGHS/LOWS. IF YOU HAVE COMMENTS ON THE NEW FORECAST DISCUSSION FORMAT...PLEASE E-MAIL THEM TO W-OAX.WEBMASTER@NOAA.GOV OR CALL DAVE THEOPHILUS AT 402 359-5166. .OMA...NONE. MEAD ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 330 AM CDT SAT APR 27 2002 FORECAST FOCUS ON POSSIBLY HEAVY RAIN EVENT WITH STRONG STORM SYSTEM LATER TODAY AND TONIGHT. IN THE SHORT TERM...ETA/AVN/NGM/RUC IN VERY CLOSE AGREEMENT BRINGING LOW FROM ROCKIES ACROSS THE NEBRASKA/KANSAS BORDER WITH TIME. LARGE WARM AIR ADVECTION PRECIPITATION ALREADY IN ADVANCE OF LOW ENTERING MIDDLE MISSISSIPPI VALLEY. PROGS CORRECTLY INTENSIFY THIS LOW AS MANY FACTORS FAVOR ALREADY IN PLACE. 850 MILLIBAR AND 1000/850 MILLIBAR LOW LEVEL WINDS PROGGED TO INCREASE WITH TIME AHEAD OF SURFACE SYSTEM WITH NOSE OF LOW LEVEL JET POINTED AT CWA MAINLY BETWEEN 18Z AND 00Z TONIGHT. GOOD UPPER JET WITH ASSOCIATED 500 MILLIBAR VORTICITY NOW EJECTING OUT FROM BASE OF UPPER TROUGH AROUND TEXAS PANHANDLE AREA WITH PROVIDE ENERGY TO APPROACHING SYSTEM. MAIN CONCERN FOR CWA IS POTENTIAL FOR HEAVY RAINFALL. PROGS AGREE THAT DURATION OF RAIN WILL OCCUR MAINLY THIS AFTERNOON AND OVERNIGHT. WHILE VERY DEEP LOW LEVEL MOISTURE DOES NOT GET PULLED INTO SYSTEM...THIS SYSTEM WILL BE VERY EFFICIENT IN SQUEEZING OUT ALL AVAILABLE MOISTURE. PROGGED PRECIPITABLE WATER VALUES INCREASE TO AND RANGE FROM 0.80 TO 1.2 INCHES DURING EVENT. 6 HOUR FLASH FLOOD GUIDANCE CURRENTLY RUNNING BETWEEN 1.5 AND 2.8 INCHES. DID CONTEMPLATE A FLOOD WATCH FOR TONIGHT...AS THIS IS A VERY CLOSE CALL. HAVE OPTED HOWEVER...TO REISSUE ESF AND MENTION/HIGHLIGHT LOCALLY HEAVY RAIN IN BODY OF FORECAST. FEEL THERE IS STILL ENOUGH TIME BETWEEN OCCURANCE OF RAINFALL AND RESPONSE OF RIVERS...GIVEN THEIR CURRENT LEVELS...TO ISSUE A FLOOD WATCH LATER TODAY IF MORE MOISTURE IS BEING ADVECTED INTO SYSTEM. IN THE FAR TERM...HAVE SIDED WITH AVN WHICH LINGERS PRECIPITATION OVER CWA A LITTLE LONGER SUNDAY. WILL ADJUST THIS IN ZONES AND WILL NOT BREAK OUT CLOUDS EITHER...SO WILL LOWER TEMPERATURES A BIT. WILL ADD RAIN CHANCE FOR TUESDAY AS PER NEW AVN GUIDANCE. .MKX...NONE. $$ ZAJDEL wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1105 AM EDT SAT APR 27 2002 FCST CONCERN IS ONSET OF PRECIP/PTYPE AND HEADLINES. WV IMAGERY SHOWS A POTENT SHORTWAVE MOVING OUT INTO CNTRL PLAINS WITH IMPRESSIVE DRY SLOT DRIVING THRU KS. STRONG SHORTWAVE COMBINED WITH DEVELOPING CLASSIC COUPLED UPPER JET STRUCTURE BTWN 120KT JET OVER ONTARIO AND 130KT JET MOVING INTO PLAINS IS PRODUCING STRONG/BROAD UPPER DIVERGENCE OVER CNTRL U.S. THIS HAS FORCED LOW-LEVEL JET TO INCREASE TO 60KTS WITH COPIOUS MOISTURE SURGING N. PWATS HAVE INCREASED TO AN INCH AS FAR N AS IA WHICH IS ABOUT 200PCT OF NORMAL FOR THAT AREA. RADAR IMAGERY SHOWS A MASSIVE AREA OF PRECIP ACROSS PLAINS AND MIDWEST. DESPITE INITIAL VERY DRY LOW-LEVEL AIR...LEAD PRECIP BAND IS MAKING FAIRLY STEADY PROGRESS NE THIS MORNING. SUBFREEZING WETBULB PROFILE IN THE SHALLOW ABOVE FREEZING NEAR SFC LAYER ON 12Z KGRB SOUNDING ARGUES FOR MAINLY SN AS PRECIP STARTS TO REACH THE SFC. SFC DWPTS INITIALLY IN THE TEENS/20S OVER FA ALSO LEND SUPPORT FOR MAINLY SN AS PRECIP BEGINS. SO SNOW SHOULD BE DOMINANT PTYPE THIS AFTN. HOWEVER...CAN'T IGNORE HIGH LATE APRIL SUN ANGLE WHICH WILL HAVE SOME IMPACT DESPITE THICK CLOUD COVER. THIS WILL INFLUENCE POTENTIAL SNOW ACCUMULATIONS MORE SO THAN PTYPE. WILL CONTINUE WITH CURRENT FCST WORDING OF SN MIXED WITH RN. PRECIP SHOULD GENERALLY BE LIGHT TODAY AS WEAK LEAD SHORTWAVE DEPICTED BY RUC ANALYSIS OVER SRN MN MOVES NE WITH PRECIP BAND HAVING TO WORK THRU DRY LAYER. THE LIGHTER PRECIP COMBINED WITH DIM SUN THRU CLOUD DECK SHOULD RESULT IN MINIMAL SN ACCUMULATIONS...AND ROADWAYS SHOULD REMAIN JUST WET. FOR THIS REASON...NOT INCLINED TO START HEADLINES ANY SOONER THAN IS INDICATED IN CURRENT FCST AS MAIN SHOW IS TONIGHT. STRONGEST FORCING AND HEAVIEST PRECIP WILL OCCUR TONIGHT AS MAIN SHORTWAVE MOVES INTO WRN LAKES. 06Z ETA TRENDED FARTHER N WITH MUCH HEAVIER PRECIP AMOUNTS OVER FA...GENERALLY 0.5 TO 1 INCH MORE THAN 00Z RUN! 06Z ETA HAS TOTALS RANGING FROM 0.5 INCHES OVER KEWEENAW TO A SWATH OF 1.75 INCHES FROM KIMT TO KISQ...INCLUDING 1.5 INCHES AT KMQT. WILL NOT JUMP ON THIS YET AS 06Z AVN SHOWED NO CHANGES FROM ITS 00Z RUN. WILL AWAIT 12Z MODEL RUN DATA...BUT STRENGTH OF SYSTEM AND STRONG NWD SURGE OF COPIOUS MOISTURE DOES GIVE SOME BELIEVABILITY TO THE WETTER 06Z ETA RUN. .MQT...WINTER STORM WRNG TNGT AND EARLY SUN MIZ012. SN ADVY TONIGHT MIZ002-003-009. SN ADVY TONIGHT/EARLY SUN MIZ004>007-010-011-013-014. ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 1026 AM EDT SAT APR 27 2002 WILL JUST MAKE SOME TIMING CHANGES TO ONSET OF PRECIP LATER THIS AFTERNOON AND TONIGHT. LATEST RUC DLAYS ONSET TIL LATE AFTN MOST OF OUR OH AND EXTRM WESTERN PA ZNS. REST LEFT AS IS. .PBZ... MD...NONE. OH...NONE. PA...NONE. WV...NONE. pa AREA FORECAST DISCUSSION FOR CENTRAL/N-EAST SD AND W-CENTRAL MN NATIONAL WEATHER SERVICE ABERDEEN SD 950 AM CDT SAT APR 27 2002 MOST RECENT RUC TRYING TO INDICATE SOME WEAK CAA JUST ABOVE THE SFC ACROSS FAR ERN PORTIONS OF THE CWA TODAY AS WINDS REMAIN MORE ERLY THAN SERLY. THIS LOW LVL CAA SEEMS REASONABLE GIVEN COOLER TEMPS OVER WRN MN ATTM. WITH UPPER CIRCULATION SLIDING SOUTH OF THE REGION LATER TODAY WILL BE HARD PRESSED TO SEE ANY WAA OVERSPREAD THIS AREA. WRN SECTIONS SHOULD BEGIN TO PICK UP LOW CAA LATER THIS AFTERNOON AND INTO THE EVENING BEHIND INVERTED TROF SLIDING EAST THROUGH THE EVENING. CO-OP OBSERVER FROM ERN SD CALLED RECENTLY WITH A REPORT OF SNOW FALLING NEAR THE MN BORDER. WITH THIS REPORT...AND THE LIKELIHOOD THAT WEAK CAA WILL CONTINUE THROUGH THE DAY WILL UPDATE ZONES TO REFLECT SNOW MIXING WITH THE RAIN ACROSS THE FAR EAST AND TEMPS NOT WARMING AS PREVIOUSLY THOUGHT. .ABR....NONE. FAUCETTE sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD, VA 1005 AM EDT SAT APR 27 2002 DRY AIR HANGING TUFF ACRS FA WITH CONFLUENT UPR FLOW TO NE HELPING TO STRENGTHEN RDGG. LTST VIS SATL LOOP SHOWING CLOUDS HAVING TROUBLE OVERCOMING DRY AIR ACRS CNRTL/NRN MID ATLC STATES. PER MHX 88D LOOP...SHRAS ALG NC CST MAKING LTL NWD PROGRESS AND DRYING UP ACRS PAMLICO SOUND. REGIONAL RADARS INDICATE LEADING EDGE PCPN ASSOCD WITH MAIN S/W IN CNTRL US STILL WELL BACK IN LWR OHVLY. SO WITH CURRENT TRENDS AND LTST (DRIER) RUC/MESOETA GUIDANCE...WL BE MORE OPTIMISTIC WITH THIS AFTN FCST. KEEPING (LOW) PCPN CHCS CONFINED TO NE NC/SOUTHSIDE HAMPTON ROADS IN CASE A FEW SHRAS SNEAK UP THE COAST. WL ALSO BUMP UP TEMPS A CAT MOST PLACES PER PROLONGED PD SUNSHINE THRU MIDDAY AND INTO EARLY AFTN. RMNDR FCST UNCHANGED. PREV DISC BLO: -------------------------------------------------------------------- COOL/CLR NGT ACRS FA...WITH SFC HI PRES SETTLING BY JUST N OF RGN. AREA OF RA MVG TO THE SC/GA CST ATTM...BUT MAIN ACTION GETTING GOING WELL W OF THE MTNS. WITH SFC HI PRES MVG OFFSHR THIS MORNING...LLVL FLO TURNS SE...AS LRG AREA OF WAA INDUCED PCPN DVLPS OVR MID MS VLY AND HEADS E. WL HV SUM SUNSHINE EVERYWHERE TO START THE DAY...HWVR AFTN HRS BCM CLDY. ETA MDLS SNDGS DO NOT SHOW SUFFICIENT SATURATION FOR WDSPRD RA THIS AFTN/EVE...BUT WL CVR FOR LO CHCS LT/EVE FOR WRN HALF OF FA. BEST PD FOR PCPN COMES TNGT THRU SUN MORNING AS WRMFNT LIFTS NE THRU RGN. CONTG TO XPCT HVYST PCPN TO PASS BY TO THE NW. WL NOT GO WITH 80% AND > AS GUIDANCE SUGGS...GOING WITH LIKELY ALL AREAS INSTEAD. WRMFNT LIFTS TO THE NE OF FA BY ERY AFTN HRS...LLVL FLO INCRSS FM WSW DRCTN AND SGFNT WRMG TO OCCUR. H85 TEMPS PROGGED TO RISE TO ARND +15 DEGS C DURG AFTN HRS. LATEST TEMP GUIDANCE SUGGS READINGS REACHING MID/UPR 80S AS SKY PRTLLY CLRS. XPCTG AIR TO DRY SUFFICIENTLY TO LMT CHCS OF ANY TSRAS...SO WL GO W/O ANY MENTION OF PCPN FOR AFTN HRS MOST PLCS. SLGT TMG DIFFS WITH SFC CDFNT PASSING THRU RGN SUN NGT (AVN FASTER THAN ETA). THINK THERE CUD BE A BKN LN OF CNVTN WITH FNT (DESPITE TM OF DAY)...CONSIDERING WRM/MOD INSTABILITY OVR FA...NOT XPCTG ANYTHING TOO WDSPRD AT THIS TM. DRYING/COOLING DN FOR MON AND TUE...B4 ANOTHER VRY WRM SURGE OF AIR MVS INTO RGN FM SW ON WED. YET ANOTHER COOLDOWN BY FRI. MADE MINOR ADJSMNTS TO WED AND FRI FCSTS TO RELECT THESE IDEAS. FCSTID = 25 ------------------------------------------------------------------- .AKQ... MD...NONE. NC...NONE. VA...NONE. CULLEN va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 245 PM CDT SAT APR 27 2002 POTENT SYSTEM WINDING UP ACROSS NEBRASKA WITH MODELS DISAGREEING ON EVENTUAL TRACK. 15Z RUC APPEARS TO HAVE BEST IDEA OF SENDING SURFACE LOW JUST EAST OF KOMA BY 00Z (NEAR KAIO). THIS AGREES BEST WITH AVN AND TO SOME EXTENT THE NGM. EXTRAPOLATION WOULD INDICATE THAT AVN IS BETTER IN FUTURE POSITIONS OF LOW...WHICH WOULD INDICATE WARM FRONT NOT GETTING MUCH FURTHER NORTH THAN I80. EITHER WAY MODELS INDICATE TREMENDOUS LIFT TO CONTINUE DURING THE NIGHT WITH A SATURATED ATMOSPHERE. BRIEF LULL IN THE PRECIP EXPECTED THIS EVENING BEFORE STARTING UP AGAIN. APPEARS THAT SOUTHERN PART OF CWFA SHOULD SEE SOME SOLAR HEATING LATE THIS AFTERNOON AND EVENING AS DRY SLOT CONTINUES EAST. UNFORTUNATELY THIS RAISES POTENTIAL FOR SEVERE WITH LOW TOPPED SUPERCELLS VERY LIKELY. APPEARS SOUTHERN PART CAN EXPECT THE WORST WITH HAIL/HIGH WINDS. BETWEEN I80 AND HIGHWAY 30 EVERYTHING IS POSSIBLE INCLUDING TORNADOES. RAIN AND COOP REPORTS INDICATE AMOUNTS OF 3/4 TO 1.5 INCHES OF PRECIP DEPENDING ON LOCATION. GROUND NOW VERY MOIST AND POTENTIAL THERE FOR ANOTHER HALF TO 1 INCH. THEREFORE WILL CONTINUE FLOOD WATCH FOR TONIGHT. MODELS INDICATE PRECIP TO TAPER TO DRIZZLE AFTER MIDNIGHT WITH DRIZZLE LIKELY DURING THE MORNING HOURS. EVENTUAL STRONG CLEARING TO OCCUR DURING THE AFTERNOON FROM SOUTH TO NORTH. MONDAY ANOTHER SHORTWAVE MOVES THROUGH BRINGING A THREAT OF TSRA/SHRA DURING THE AFTERNOON AND EVENING HOURS FOLLOWED BY A BRIEF LULL IN ACTIVITY. GUIDANCE SIMILAR BUT FAN/MAV ARE COOLER THROUGH THE PERIOD. TENDENCY IS TO FOLLOW MAV NUMBERS BUT SOUTH PART OF CWA COULD BE CLOSER TO FWC ONCE THE SUN COMES OUT ON SUNDAY. EXTENDED...NOT MUCH TIME TO LOOK AT BUT ANOTHER SIGNIFICANT SYSTEM TO AFFECT THE AREA WED/THU WITH RAIN LIKELY AGAIN. WILL KEEP FRIDAY DRY FOR NOW AS WELL AS SATURDAY...BUT WOULD NOT BE SURPRISED IF SOME PRECIP OCCURRED ON SATURDAY. COORDINATE WITH DSM...ILX...AND CHI. .DVN...FLOOD WATCH ENTIRE CWA TONIGHT. IA...IAZ040>042-051>054-063>068-076>078-087>089-098-099. IL...ILZ001-002-007-009-015>018-024>026-034-035. MO...MOZ009-010. 86 il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 215 PM CDT SAT APR 27 2002 VRY DECENT RAINS ACRS THE FA TDA WHICH WERE NEEDED. POTENT DRY SLOT AND ASSOC MID-LVL TROF WL SWING ACRS IA TNGT WITH ALL NECESSARY CONVECTIVE PARAMETERS AVAILABLE. SVR WX WL LIKELY OCCUR ALG TRIPLE PT OF CIRC CENTER AND SWD ALG DRY LN. SOME HIGHER BASED HAILERS ARE PSBL N OF WRMFNT. THERE WL BE A SMALL WINDOW OF TORNADO OPPORTUNITY AS THE SYS RPDLY MOVS FM CBF-DMX-MIDWAY ALO/CID THIS EVEN. ETA/RUC THE BEST MDL AT THIS TIME COMPARING GOES LI/CAPES TO THE MDL FCSTS. OUTSIDE OF THE SVR WX THREAT THIS EVEN...PSBL NRW BAND OF SNOW FM MCW TWDS SLB FOR SVRL HRS THIS EVEN AS SYS TAPS COLDER AIR ALG IA/MN BDR. CLDS TMR IN CYC FLOW WITH SUNSHINE SWRN THIRD OF SO IN THE AFTN. NRN BRANCH TROF AND WK WAA ON MON WITH SML POPS. AT THE MOMENT WE HAVE THAT GOING BUT NOT EXCITED ABT IT. QG FORCING SPLITS THE ST AS TROF COMES ACRS WITH LTL WAA ADDITION. WL PROBABLY HOLD ON THAT SML CHC TO PREVENT YO-YO. NXT SYS ARRIVING TUE NGT INTO WED NGT AS SRN BRANCH REACTIVATES IN BROADSCALE OVERRUNNING EVENT SIMILAR TO CURRENT SITUATION. HOLDING DRY THU ON. TMPS ABT AS SUGGESTED. .DSM...NONE MYERS ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 332 PM CDT SAT APR 27 2002 SECOND WEEKEND IN A ROW OF WINTRY WEATHER. RAIN HAS PRETTY MUCH CHANGED TO SNOW IN THE TWIN CITIES METRO AREA. SNOW CONTINUES ACROSS THE NORTHERN AND EASTERN SECTIONS OF THE CWA WITH OBSERVERS REPORTING UP TO TWO INCHES IN AMERY. SOME SLEET MIXING IN. RUC 950MB TEMPERATURES INDICATING A CIRCULAR 0 DEG ISOTHERM OVERHEAD THAT EXPANDS RAPIDLY TO THE WEST AND EAST THROUGH 7 PM. THIS SHOULD CHANGE ANY MIXED PRECIPITATION TO ALL SNOW OVER ALL BUT THE FAR SOUTHERN COUNTIES IN MN. BEST FORCING IS ACROSS WI EARLY TONIGHT WITH MIXING RATIOS OF 3 G/KG. ALREADY UPDATED EARLIER THIS AFTERNOON AND PUT MORE COUNTIES TO THE NORTH AND EAST OF THE TWIN CITIES IN A WINTER WEATHER ADVISORY. THINGS REALLY DIMINISH DURING THE EARLY MORNING HOURS WITH ONLY A CHANCE OF LIGHT SNOW INDICATED FOR SUNDAY MORNING OVER THE EASTERN HALF OF THE CWA. A RATHER ABRUPT CHANGE TAKES PLACE SUNDAY AFTERNOON AS LOW LEVEL WARM ADVECTION TAKES CHARGE AS A TROUGH ADVANCES TOWARDS US FROM CENTRAL CANADA. STUCK WITH THE CHANGE OF SHOWERS LATE SUNDAY NIGHT WESTERN AREAS AND DURING THE DAY ON MONDAY EASTERN AREAS. INDICES INDICATE A SMALL CHANCE FOR THUNDER. A RATHER BROAD LOW PRESSURE SYSTEM TO OUR NORTH FOR MUCH OF NEXT WEEK KEEPING TEMPERATURES MORE IN THE 55 TO 60 DEGREE RANGE. .MSP...WINTER WEATHER ADVISORY TONIGHT MNZ044-045-052-053-061-063-WIZ014>016-023-025-027-280900- HILTBRAND mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 330 PM CDT SAT APR 27 2002 AFTER WAITING AND WATCHING THINGS ARE FINALLY BGNG TO GET GOING OUT WEST. THE MID LVL DRY SLOT CONTS TO SURGE EWD ACRS THE FA ON THE HEALS OF THE ERN MO IMPULSE HELPING ALG WITH WAA GENERATE THE SECOND WV OF SHRA AND EMBDD -TSRA NOW MOVG EAST OF THE MS RVR. SCT CNVCTN IS NOW DVLPG ALG DRYLN FM SE NEB INTO ERN KS WHERE CLDS HV CLRD AND DIURNAL HTG AND PBL MSTR ADVCTN HAS RESULTED IN A SWATH OF SFC BASED INSTABILITY. THE BIG QUESTION IS HOW FAR EWD THE INSTABILITY WL SPRD DURING THE COURSE OF THE EVNG AND THE EXTENT OF THE CNVRGNC ALG THE DRYLN. WRMFNT WAS LCTD FM SRN IL ACRS THE LAKE OF THE OZARKS INTO NW MO AT 20Z AND XTNSV LOW CLDS RMND OVR ALL OF THE BI-STATE. STILL ALL THE MDLS INCLUDING THE LAST SVRL RUC RUNS ARE INDCG BOTH AN INCRS IN SFC DPTS AND TMPS THRU THE RMNDR OF THE AFT AND INTO THE EVNG IN ADVANCE OF EWD SURGING DRYLN. THIS INCRS IN PBL MSTR/HEAT AND GOOD MID LVL CAA RESULTS IN THE MDLS MAINTAINING THE SWATH OF UNSTBL AIR WELL PAST SUNSET INTO THE NGT IN ADVANCE OF THE STG SYS. DP LYR SHEAR IS IMPRSV TO SAY THE LEAST WITH LATEST LAPS 0-6KM BULK SHEAR AT 70-80 KTS...AND VALUES CLOSE TO THESE SHUD BE MAINTAINED DURING THE EVNG AS THE MID LVL JET CONTS TO PROP EWD IN ASSOCN WITH THE STG SHRTWV TROF. THUS SVR THREAT STILL LOOKS GOOD IF PROGGED DESTABILIZATION IS INDEED CORRECT. NATURE TO THE FRCG SUGGESTS THAT COVERAGE OF STRMS SHUD BE SCT AND WL WORD AS SUCH...ENDING WEST TO EAST DURING THE TNGT PD. FAIRLY GOOD DRYING BHD THIS SYS AND MDLS ARE ALL NOW A BIT COOLER THAN PRVS RUNS FOR SUN/SUN NGT. HV TRENDED THE NEW FCST DOWNWARD A TAD MORE BASICALLY SPLITTING THE DIF IN THE MAV/FWC NUMBS. WL PRBLY SEE SOME WRAP ARND CLDS WORK INTO THE FAR NORTH LATE TNGT AND AT LEAST SCT INSTABILITY CU FRM SUN MRNG IN THE CYCLONIC FLOW IN THE WAKE OF THE LOW OVR THE NRN/ERN SXNS. BREEZY AS WELL. SFC HI BLDS ACRS SUN NGT WITH ANY LINGERING INSTAB CU DSIPTG AND LVG MCLR SKIES FOR A WHILE. MDLS HOWEVER BGN SPRDG WAA CLDS ACRS THE NRN HALF OF THE CWFA LATE SUN NGT IN ADVANCE OF A QUICK MVG IMPULSE. HV KEPT THE FCST DRY BUT WL HV TO WATCH TO SEE IF A FEW SHRA MAY DVLP FM MID LVL MSTR DECK. FM MON AND BYD THE FCST DETAILS BCM LESS CLR. THE NEW AVN IS MUCH DIF THAN THE PRVS RUN AND HAS TRENDED TWDS YDAS CANADIAN AND THE LATEST UKMET/ECMWF SHWG MORE NRN STRM AMPLIFICATION AND THUS THE SWD FNT PROGRESSION ON MON/MON NGT IS ABT 24H FASTER THAN PRVSLY FCST. I HV KEPT SOME POPS GOING WITH IT AND HV TAILORED TMPS A BIT. THE EXACT PSN AND WAVERING IN RSPNS TO SHRTWVS STILL RMNS QUESTIONABLE INTO WED. ATTM AVN SUGGESTS THREAT OF ELEVATED TRW TUE NGT INTO ERLY WED THEN SFC BASED STRMS LATE WED/WED NGT WITH SFC WV TRANSLATING ALG THE E/W BNDRY. .STL...NONE GLASS mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 325 PM CDT SAT APR 27 2002 FORECAST CHALLENGE BEYOND SHORT TERM IS A SERIES OF SYSTEMS OUT OF BOTH BRANCHES OF FLOW. MAIN SYSTEM SEEMS TO BE TIMED FOR WED. IN THE SHORT TERM...VERY FAST MOVING LOW WILL PRODUCE MAIN SEVERE THREAT THE REST OF THE AFTN INTO EARLY EVE. GOOD SETUP FOR MINI SUPERCELLS WITH THIN WEDGE OF WARM MOIST AIR JUST AHEAD OF SFC LOW WHILE COLD AIR PUNCHES IN AT 700 MB BENEATH LOW TROP. AFTER SYSTEM MOVES THROUGH...WINDS PICK UP FOR A WHILE WITH SOME LIGHT RAIN WRAPPING AROUND THRU NRN AND CENTRAL COUNTIES. RAINFALL SO FAR 1 TO 2 INCHES MANY LOCATIONS...BUT PRESENT SYSTEMS MOVING SO FAST THAT FLASH FLOOD THREAT IS NOT WORTH MENTIONING. LATER TONIGHT STRATOCU WRAPAROUND WILL CONTINUE THROUGH MOST OF THE AREA...BUT EXPECT IT TO BREAK UP EARLY SUNDAY AS ANTICYCLONIC FLOW TAKES OVER. NEXT SYSTEM IS A FAIRLY WEAK LOOKING WAVE...BUT IT GENERATES IMPRESSIVE LIFT IN THE MID LEVELS OF ETA IN PARTICULAR. WORTH A SLIGHT CHC OF SHOWERS LATE SUN NIGHT AND MON MORNING. NEXT SYSTEM APPROACHES LATER TUE INTO WED. THIS ONE LOOKS MORE IMPRESSIVE AND SHOULD BE TAPPING GULF MOISTURE. MODELS DISAGREE ON STORM TRACK...BUT BEST CONSENSUS APPEARS TO BE ACROSS KS. KEPT POPS HIGH AND TEMPS COOL. LATER IN THE EXTENDED...CONDITIONS APPEAR TO BE DRY AS THE AREA STARTS OUT UNDER HIGH PRESSURE THEN GETS INTO RETURN FLOW BY SAT...BUT REMAINS WELL AWAY FROM THE STORM TRACK THROUGHOUT. WENT WITH TOP AND EAX FOR A DRY FORECAST. 125 AM CDT SAT APR 27 2002 FORECAST CHALLENGES -- SEVERE WEATHER POTENTIAL TODAY SYNOPSIS -- LATEST REGIONAL 88D REFLECTIVITY MOSAIC/IR IMAGERY SHOWS INCREASING CONVECTIVE ACTIVITY FROM S-CNTRL NEB TO ERN KS. THESE STORMS ARE FORMING IN A ZONE OF INTENSE WARM ADVECTION/ISENTROPIC LIFT AND ON THE NOSE OF INCREASING 850 MB MOISTURE, PER OUN 27/00Z SOUNDING AND 27/03Z RUCII DATA. AT THE SURFACE, A DEEPENING LOW WAS SITUATED OVER NERN NM AT 06Z, WITH THE PRIMARY WARM FRONT STILL WELL TO OUR S, OVER N-CNTRL TX. FORECAST -- SEVERE WEATHER POTENTIAL IN THE NEXT 2-4 HOURS AND THEN AGAIN THIS AFTERNOON ARE THE MAIN CONCERNS. THE ETA AND AVN ARE NOW IN FAIRLY GOOD AGREEMENT ON THE MASS FIELDS THROUGH THE FIRST 24 HOURS. IN THE SHORT TERM, CONTINUED MOIST/THERMAL ADVECTION IN THE LOW LEVELS WILL INCREASE CHANCES OF ELEVATED SEVERE CONVECTION EARLY THIS MORNING. 27/03Z RUCII FORECAST SOUNDINGS FOR SERN NEB SHOW MUCAPE VALUES INCREASING TO AROUND 1000 J/KG BY 09Z WITH SUFFICIENT SHEAR THROUGH THIS BUOYANT LAYER TO SUPPORT ELEVATED MESOCYCLONES. THEN, ATTENTION TURNS TO THE INTENSE MID-LEVEL SHORTWAVE CURRENTLY OVER NM AS OF 06Z. THIS FEATURE WILL RAPIDLY EJECT NEWD TODAY WITH A POTENT SURFACE CYCLONE MOVING FROM N-CNTRL KS/S-CNTRL NEB INTO SWRN IA BY 28/00Z. THE AMOUNT OF SEVERE WEATHER IN OUR CWA TODAY WILL BE CONTINGENT ON TWO FACTORS: 1) THE AMOUNT OF QUALITY MOISTURE RETURN, AND 2) THE DEGREE OF AIRMASS MODIFICATION AHEAD OF THE SURFACE LOW. 06Z METAR DATA SUGGESTS 1) MAY BE THE MOST PROBLEMATIC AS THE GOOD SURFACE DEWPOINTS (I.E. 55-65) ARE STILL OVER TX. EVEN WITH INTENSE CYCLOGENESIS, THIS MOISTURE WILL LIKELY NOT MAKE IT, ESPECIALLY GIVEN OUR SURFACE TRAJECTORIES (SE). THUS, THE BEST CHANCES FOR 50S DEWPOINTS WILL NOT BE ADVECTIVE, BUT FROM AIRMASS SATURATION DUE TO THE ONGOING CONVECTION. THIS LEADS TO 2). HOW MUCH AIRMASS RECOVERY WILL OCCUR AHEAD OF THE SURFACE LOW? BOTH THE ETA AND AVN INDICATE AN IMPRESSIVE DRY SLOT MOVING INTO SERN NEB/SWRN IA BY 18Z, SO IT APPEARS SOME DESTABILIZATION IS POSSIBLE. GIVEN THE DYNAMICS OF THE SYSTEM, ONLY 500-1000 J/KG WILL LIKELY BE NECESSARY TO INITIATE SURFACE-BASED CONVECTION. LOW LCL HEIGHTS AND HIGH 0-1 KM SRH/SHEAR VALUES NE OF THE SURFACE LOW, SUGGEST GOOD LOW-TOPPED TORNADIC SUPERCELL POTENTIAL *IF* CONVECTION CAN INITIATE IN OUR CWA. WE WILL HIT THIS SCENARIO RATHER HARD ACROSS OUR SERN ZONES IN THE HWO. THIS SYSTEM WILL RAPIDLY MOVE TO THE E TONIGHT, WITH SOME LINGERING PRECIPITATION THIS EVENING. BOTH THE AVN/ECMWF INDICATE THE NEXT CHANCE OF PRECIPITATION WILL OCCUR ALONG AND TO THE N OF A FRONTAL BOUNDARY THAT WILL BE SLOWLY SAGGING THROUGH THE AREA TUESDAY NIGHT/WEDNESDAY. OTHERWISE, GUIDANCE TEMPERATURES LOOKS REASONABLE ON HIGHS/LOWS. MEAD IF YOU HAVE COMMENTS ON THE NEW FORECAST DISCUSSION FORMAT...PLEASE E-MAIL THEM TO W-OAX.WEBMASTER@NOAA.GOV OR CALL DAVE THEOPHILUS AT 402 359-5166. .OMA...NONE. POLLACK ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBUQUERQUE NM 1055 AM MDT SAT APR 27 2002 FORECASTS UPDATED FOR MORE WIND THIS AFTERNOON PER LATEST RUC2 AND LAMP OUTPUT. 38 .ABQ...WIND ADVISORY THIS AFTERNOON NMZ005>007-010>013-018-020-021. nm