WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 145 PM MDT TUE MAY 16 2000 INCOMING UPPER LOW MAKING SLOWER EASTWARD PROGRESSION TODAY THAN PREVIOUSLY FORECAST. AT 18Z LOW APPEARED TO BE CENTERED OVER EASTERN NV IN VICINITY OF EKO. SHORT TERM MODELS NOT OFFERING SOLID GUIDANCE FROM THAT POINT FORWARD WITH ETA TRACKING THE LOW SOUTHEAST INTO CENTRAL UT THEN THROUGH SOUTHERN PORTION OF CWA WEDNESDAY WHILE AVN...NGM AND RUC TAKE IT THROUGH UT PANHANDLE AND ACROSS NORTHERN PORTION OF CWA. CONSIDERING CURRENT LOCATION...AND LACK OF ANY OTHER FEATURES TO STEER THE SYSTEM FURTHER SOUTH...AM LEANING WITH THE MORE NORTHERLY SOLUTIONS. OF THESE...NGM WANTS TO KICK THE SYSTEM EASTWARD MORE QUICKLY THAN AVN. AS MENTIONED EARLIER...SYSTEM ALREADY MOVING MORE SLOWLY THAN EXPECTED...SO MODEL OF CHOICE TODAY IS AVN. WIND CONTINUES TO BE PRIMARY FOCUS OF FORECAST PACKAGE. JET MAX COVERED MOST OF CWA THIS MORNING AND AS LOW MOVING INLAND SLOWLY EXPECTED TO BE OVER CWA AT LEAST THROUGH EARLY TONIGHT. WIND ADVISORY IN PLACE FOR ENTIRE CWA TODAY...AND TO BE EXTENDED AT LEAST INTO EVENING HOURS. WILD HORSE GULCH UT JUST BELOW WARNING CRITERIA AT 19Z...WILL MONITOR CLOSELY AND MAY UPGRADE PORTIONS OF ADVISORY TO WARNING. ALSO RED FLAG WARNING OUT THROUGH THE EVENING FOR CENTRAL AND SOUTHERN PORTIONS OF WESTERN CO. BY 12Z WEDNESDAY...BACKSIDE OF LEADING EDGE OF TROUGH MOVING INTO CWA WITH JET INTO EASTERN CO WHICH SHOULD KEEP WIND BELOW ADVISORY CRITERIA. SUBTROPICAL TAP OF MOISTURE HAS BEEN SHUNTED EASTWARD WITH DRY SLOT WORKING OVER CWA TODAY. HOWEVER...ENOUGH MOISTURE ALREADY WRAPPED INTO LOW TO SET OFF THUNDERSTORMS OVER NV AND ID. WITH SEVERAL SMALL BUT IMPRESSIVE VORTICITY CENTERS EMBEDDED IN LOW...BELIEVE CHANCES FOR WRAP AROUND PRECIP STILL VALID AND WILL NUDGE POPS UP A CATEGORY WEDNESDAY IN FAVORABLE LOCATIONS. DYNAMICS LINGER OVER CWA THROUGH THURSDAY AND SPLIT DEVELOPS IN FLOW ALOFT. WILL CONTINUE MENTION OF AT LEAST WIDELY SCATTERED SHOWERS AND THUNDERSTORMS. FOR TEMPERATURES...700MB TEMPS DROP FROM APPROX 12C MONDAY AFTERNOON TO APPROX 2C WEDNESDAY AFTERNOON. WEDNESDAY TO BE NOTABLY COOLER AND BELIEVE CURRENT TREND OF 10 TO 20 DEGREES COOLING APPROPRIATE. FOR EXTENDED...LARGE HIGH PRESSURE RIDGE REMAINS OVER EASTERN PACIFIC UNTIL LATE IN EXTENDED WHEN IT BEGINS TO SHIFT EASTWARD. PATTERN KEEPS A WEST TO NORTHWEST FLOW INTO CWA THROUGH EXTENDED PERIOD PREVENTING A DRAMATIC WARMUP...BUT KEEPING TEMPERATURES CLOSER TO SEASONAL NORMALS. SEVERAL EMBEDDED DISTURBANCES WILL RIDE ALONG FLOW PASSING THROUGH CWA...HOWEVER AT THIS TIME MOST APPEAR TO BE RELATIVELY WEAK LIKELY CAUSING ONLY WIDELY SCATTERED SHOWERS AND THUNDERSTORMS. FOR TIME BEING WILL KEEP PACKAGE AS IS WITH MENTION OF SLIGHT CHANCES THROUGH WEEKEND. WESTERN COLORADO AND EASTERN UTAH EMERGENCY MANAGERS SHOULD MAINTAIN A HIGH LEVEL OF WEATHER AWARENESS THIS EVENING DUE TO STRONG SOUTHWEST WINDS. .GJT...WIND ADVISORY FOR THE ENTIRE FORECAST AREA EARLY TONIGHT. GL co EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 955 AM EDT TUE MAY 16 2000 FEW SHRA MOVING S ACROSS COASTAL WATERS MAY MOVE ONSHROE ALONG VOLUSIA CTY SOON. MORNING SOUNDING CAME IN A BIT DRIER THAN YESTERDAY BUT STILL QUITE UNSTABLE WITH CONVECTIVE TEMPS MUCH LESS THAN YSTRDY. NOT CU ALREADY FORMING OVER COASTAL CTYS ATTM. CAPE VALUES NEAR 2000 J/KG ACHIEVED AT TEMPS ONLY IN THE LOW 80S. WHILE CURRENT FCST IS DRY XCPT S SECTIONS IT WAS BASED ON NGM POSITION OF SHORT WAVE AXIS MOVING THROUGH IN NW FLOW ALFT. IT APPEARS ETA/RUC SOLUTION IS MORE ON TRACK WITH CURRENT WATER VAPOR IMGRY WITH SMALL WV MOVING THRU THE GREAT BEND AREA. RESULT IS AIRMASS WILL REMAIN UNSTABLE AT LEAST UNTIL THIS FEATURE PULLS THROUGH...EARLY AFTERNOON N PORTIONS AND THROUGH MUCH OF THE DAY S PARTS. W/ LOW LEVEL NE FLOW THE ECSB WILL BE DIFFUSE AND MOVE QUICKLY INLAND...HOWEVER MEAN STEERING FLOW ABV BNDRY LYR IS FM THE NW AND ACTVTY HAS A CHC OF MAKING ITS WAY BACK TO THE COASTAL CTYS. WILL ADD POPS TO ALL ZONES WITH LESS THAN 20 N AND UP TO 30 OVER S SECTIONS. HAIL THREAT STILL EXISTS WITH COOL MID LEVEL TEMPS BUT COMPARED TO YSTRDY WE LACK FNTL BNDRY...SOME MOISTURE AND ORGANIZATION TO ECSB. FIRE WX...NO PROBLEMS AS AIRMASS REMAINS MOIST. MARINE...HO HIGHLIGHTS. PGRAD INDICATES WNDS SHOULD PICK UP THIS AFTN. .MLB...NONE. PUBLIC/MARINE...BLOTTMAN AVIATION/FIRE WEATHER...WIMMER fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 303 PM CDT TUE MAY 16 2000 ...MAIN FORECAST PROBLEM IS THUNDERSTORM THREAT TONIGHT AND WEDNESDAY AFTERNOON/EVENING... SURFACE DEW POINTS HAVE SURGED INTO THE MIDDLE 60S ACROSS THE CWA THIS AFTERNOON. SURFACE LOW WAS BEGINNING TO TAKE SHAPE OUT IN THE HIGH PLAINS OF CO WITH WARM FRONT FROM SOUTHWEST KANSAS INTO CENTRAL OKLAHOMA AT 18Z. 17Z HBR PROFILER HAD 700 MB TEMPS AROUND 13 TO 14 DEGREES AT 700 MB...SO WARM AIR ALOFT NOT FAR AWAY. WARM FRONT SHOULD SET UP ALONG THE NEBRASKA BORDER BY LATE EVENING AS SURFACE LOW DEVELOPS IN NORTHEAST COLORADO. WARM AIR SHOWN BY ETA TO SURGE NORTH IN THE MID LEVELS AND CAP ATMOSPHERE OFF SOUTH OF THE FRONT OVER KANSAS...UNTIL THEN WILL KEEP CHANCES FOR POPS GOING TONIGHT. THUNDERSTORMS THAT FORM IN NEBRASKA...CORFIDI VECTORS SUGGEST THAT PROPAGATION WILL BE TO THE SOUTHEAST ACROSS SOUTHEAST NEBRASKA AND NORTHEAST CORNER OF KANSAS...SO WILL GO WITH HIGHEST POPS THERE. BEST SHEAR WILL BE NEAR WARM FRONT TONIGHT WITH SVR THREAT MAINLY NEAR THE NORTHERN BORDER INTO NEBRASKA. WEDNESDAY...UPPER SYSTEM PULLS OUT INTO THE PLAINS AND RUC FORECAST SOUNDINGS SUGGEST THAT THE CAP OVER THE CWA WILL WEAKEN IN THE AFTERNOON AHEAD OF THE DRYLINE. EXPECT SCATTERED THUNDERSTORMS TO DEVELOP IN THE MID TO LATE AFTERNOON ALONG THE DRYLINE IN CENTRAL KANSAS AND PROPAGATE EAST AND FAVORABLE 0-6KM SHEAR FOR SUPERCELLS ACROSS THE CWA. MAIN THREAT LOOKS LIKE HAIL AND WIND THROUGH WEDNESDAY NIGHT. WILL CONTINUE POPS THROUGH THURSDAY AS UPPER SYSTEM MOVES INTO SOUTH CENTRAL NEBRASKA. STEEPENING LAPSE RATES ON THURSDAY WILL YIELD A CHANCE FOR SOME THUNDERSTORMS ALONG WITH SHOWERS. WILL GO A LITTLE COOLER ON WEDNESDAY WITH MORE LOW AND HIGH CLOUDS EXPECTED LIKE TODAY SO AROUND 85 ACROSS THE BOARD. WILL LEAN TOWARD THE WARMER FAN WEDNESDAY NIGHT AND ON THURSDAY. .TOP...NONE. JW ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 240 PM CDT TUE MAY 16 2000 DEEPENING UPPER LOW OVER CO WILL HAVE INDIRECT IMPACT ON AREAS WEATHER THIS PERIOD. SCATTERED CONVECTION MOVING SOUTHEAST ACROSS OK/AR PORTIONS OF AREA PROGGED BY RUC AND OTHER MODELS TO RAPIDLY DISSIPATE BY 0Z. HOWEVER...WITH REDEVELOPMENT STILL OCCURRING UPSTREAM IN OK...WILL BE PRUDENT TO LEAVE IN 20 PERCENT DURING EVENING ACROSS THESE AREAS. AFTERWARDS...DRYING WILL AFFECT EVEN THE BOUNDARY LAYER AS S-SW LOW LEVEL JET COMING STRAIGHT OUT OF THE GULF HIGH. ETA VALUES OF NEAR 95 PERCENT IN BOUNDARY LAYER CORRESPONDED TO LATE DEVELOPMENT LOW CLOUDS IN EAST TX LAST NIGHT. TONIGHTS PROGGED MAX HUMIDITY 80 PERCENT IN SAME AREA SO AM GOING TO LEAVE OUT MENTION LOW CLOUDS. USING SAME REASONING WILL REINSERT LOW CLOUDS SOUTH HALF WED NIGHT. WITH MORE STABLE AIR IN PLACE ON WED WILL GO MOSTLY SUNNY EXCEPT FOR WEAK DRYLINE TO THE WEST...GO PTCLDY NE TX WITH SLIGHT CHANCE SHOWERS WED EVENING. FIRST REAL FORCING SEEN LATER ON THU AND CONFINED NORTH SECTIONS. WEEKEND MAY BE UNCERTAIN EXTENDED AS VERY HEAVY QPF PROGGED DESPITE A LACK OF FEATURES ON HEIGHT CONTOURS. SHV 65/90/71/88 0022 TYR 64/88/71/85 0032 MLU 66/91/70/91 1001 LFK 67/92/73/89 0011 TXK 67/88/69/86 2023 .SHV...NONE. VII la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1030 PM EDT TUE MAY 16 2000 ALMOST DECIDED NOT TO GO W/ AN UPDATE THIS EVENING...BUT AREA OF LOW CLOUDS DRIFTING N TWD MNM CNTY FROM THE BAY OF GREEN BAY IS A CONCERN. 00Z GRB SOUNDING SHOWS MOIST LYR FM 992 TO 910MB W/ ENUF OF AN INVERSION ABV TO TRAP LYR OF MSTR. RUC MODEL SEEMS TO CAPTURE THE MSTR BEST...SHOWG 80 TO 85 PCNT AREA WHERE LOW CLDS ARE. 00Z RUC/18Z ETA WNDS LGT SE (VEERING SW) FLOW FM SFC THRU 925MB SHD PUSH THESE CLDS NWD TNT. WL FCST INCRSG CLDS MNM CNTY. ALSO WORRIED ABT DELTA/MANISTIQUE COUNTIES...BUT NRN FRINGE OF CLDS UPSTREAM APR TO BE FRAYING A BIT. WL INTRODUCE CLDS ALG THE LAKESHORE LATE. OTRW...NO MAJOR CONCERNS. TEMPS ON TRACK FOR CRNTLY FCST LOWS AND INCRS CNDS W ZONES STILL LOOK GOOD. MQT...NONE. DESROSIERS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1010 PM EDT TUE MAY 16 2000 SATELLITE LOOPS SHOW CLEARING NOSING EASTWARD TO JUST WEST OF SOUTHERN 4 COUNTIES OF SOUTHEAST MI. THIS TREND SHOULD CONTINUE...EXCEPT WHERE FOG/STRATUS FORMS...WHICH IS LIKELY GIVEN CLOSE TEMPERATURE/DEW POINT SPREADS WITH LIGHT WINDS AND WET GROUND. FARTHER TO THE NORTH...CLOUDS MORE RELUCTANT TO GO. RUC DOES HANG ONTO LOW LEVEL MOISTURE MORE AGGRESSIVELY IN THE NORTH THAN IN THE SOUTH TOO...TO SUPPORT CLOUDS AROUND MOST OF THE OVERNIGHT. WILL HIT FAR SOUTH HARDER FOR FOG...NORTH MORE PERSISTENT CLOUDS. WILL MENTION DENSE FOG IN THE SOUTHERN COUNTIES...BUT EXPECT WINDS THOUGH LIGHT TO BE ENOUGH TO LIFT UP A SIZABLE AMOUNT OF MOISTURE INTO STRATUS. TEMPERATURES LOOK FINE. .DTX...NONE. DWD mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 823 PM EDT TUE MAY 16 2000 RADAR LOOPS SHOW RAINFALL PEELING SWIFTLY AWAY OUT OF THE CWA. STILL SOME DRIZZLE AROUND YET FOR A FEW HOURS...AS SUPPORTING SHORTWAVE TROUGH SEEN ON WATER VAPOR LOOP RETREATS OFF TO THE EAST. WILL UPDATE FOR AREAS OF DRIZZLE YET THIS EVENING AND ADJUST WINDS TO LIGHT...OTHERWISE LITTLE CHANGE AT THIS TIME. WITH EARLIER MODEL FORECAST SOUNDINGS INDICATING PLENTY OF MOISTURE TRAPPED BENEATH STABLE LAYER ALOFT TONIGHT...AM NOT CERTAIN HOW MUCH CLEARING WILL DEVELOP TONIGHT OVER THE CWA...THOUGH LATEST RUC WOULD POINT TOWARD SOME CLEARING. RECENT RAIN WOULD CERTAINLY SUPPORT SOME DEGREE OF FOG/STRATUS LINGERING OVERNIGHT. FOR NOW...WILL LEAVE AS IS AND WATCH FOR TRENDS REMAINDER OF EVENING. .DTX...NONE. DWD mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1134 AM EDT TUE MAY 16 2000 TWO MAIN CHANGES TO THE AFTERNOON ZONES. WILL TIME THE ENDING OF THE PRECIPITATION FROM WEST TO EAST. ALSO...WILL DROP OFF TEMPERATURES TO 55 TO 60. BACK EDGE OF THE RAIN IS NOW MOVING OFF THE WISCONSIN COAST...AND SHOULD REACH MKG AROUND 1 TO 2 PM...GRR 2 TO 3 PM AND LAN 3 TO 4 PM. TOOK OUT THUNDER AS NO OBS OR LDS SHOWED SUCH ACTIVITY THIS AM. NO INTENSIFICATION EXPECTED EITHER. CLOUDS HAVE HELD TEMPERATURES DOWN...AND WILL CONTINUE TO DO SO THROUGH THE AFTERNOON. CLEARING SEEN IN SW WI WILL...MAY WORK INTO MY SOUTHERN COUNTIES THIS AFTN PER THE LATEST RUC...BUT WILL KEEP THE CLOUD WORDING AS MOSTLY CLOUDY...BASED UPON THE ETA TIMESECTION. .GRR...NONE. mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1035 AM EDT TUE MAY 16 2000 AFTN FCST CONCERNS ARE CLOUDS AND TEMPS. WV IMAGERY THIS MORNING SHOWS SHORTWAVE MOVING SE INTO THE LWR LAKES REGION. N PERIPHERY OF ASSOCIATED -RA SHIELD HAS MOVED SE OF FA. TO THE NW...ANOTHER SHORTWAVE WAS MOVING INTO CNTRL MANITOBA AND WON'T BE A FACTOR THIS AFTN. VIS IMAGERY SHOWS MSUNNY SKIES ACROSS N 1/2 OF FA WITH GENERAL DECREASE IN CLOUD COVER OVER S 1/2. FA THIS AFTN WILL BE POSITIONED IN LEFT ENTRANCE REGION OF JET STREAK ASSOCIATED WITH LWR LAKES SHORTWAVE. RESULTING SUBSIDENCE/DRYING WILL CONTINUE TO ERODE CLOUD COVER OVER S FA THIS AFTN. HOWEVER...12Z RUC/ETA FCST SOUNDINGS SHOW CONVECTIVE TEMPS IN THE 55-60 RANGE. SO EXPECT DAYTIME HEATING TO PRODUCE SOME HIGHER BASED FLAT CU. LIGHT GRADIENT WIND WITH SFC HIGH PRESSURE RIDGE EXTENDING ACROSS LK SUPERIOR THIS AFTN WILL ALLOW FOR LK BREEZE DEVELOPMENT. CURRENT FCST ADDRESSES THIS WITH COOLER TEMPS NEAR THE LAKES. INLAND... FORECAST SOUNDINGS FROM 12Z RUC/ETA INDICATE MAX TEMPS IN THE LWR 60S IF MIXING OCCURS TO AROUND 800MB OR SO. THIS IS IN LINE WITH GOING FCST. MINOR CHANGES TO WINDS/SKY CONDITION WILL BE MADE ON UPDATE. MQT...NONE. ROLFSON mi SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 830 PM MDT TUE MAY 16 2000 ...NO UPDATE TO TFX ZONE FORECASTS... DEFORMATION AXIS OVER N CENTRAL MT KEEPING BULK OF DYNAMICS/MOISTURE S OF A GTF-LWT LINE THIS EVE. PREVIOUS MODEL RUNS WERE PRETTY CONSISTENT WITH THIS SOLTN. NEW ETA INITIALIZES STRONGER UVV AT 00Z...BUT WEAKENS IT RAPIDLY BY 06Z. LATEST RUC HAS NO SURPRISES KEEPING MOIST/UVV OVER SRN PORTIONS OF CWA. CONCERN THIS EVENING IS THAT ANY LOW/MID LVL MOIST REACHING CENTRAL AND NRN PORTIONS OF CWA WILL OVERRUN CANADIAN HI PUSHING OUT OF ALTA/SASK. FOR NOW LOOKS LIKE COOLER AMS HAVING DIFFICULT TIME CROSSING THE BDR...AND MOISTURE CONTINUES TO ROTATE OVER SRN PORTIONS OF CWA...SO WILL STAY WITH CURRENT FCST. EYSSAUTIER GTF BB 040/068 042/068 049 042112 CTB BN 038/066 042/066 045 041121 HLN BB 042/066 042/068 044 045112 BZN EB 043/065 040/067 042 047312 WEY EB 036/057 028/059 032 048512 DLN EB 041/065 039/067 040 046212 HVR BB 040/070 041/072 045 041112 LWT BB 040/064 037/066 046 043112 mt AREA FORECAST DISCUSSION ... UPDATE NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 1052 PM CDT TUE MAY 16 2000 IN THE SHORT TERM...THE THUNDERSTORM AND SEVERE WEATHER THREAT HAS DIMINISHED...ESPECIALLY OVER THE SOUTHERN PART OF THE FORECAST AREA. EVENING SOUNDINGS INDICATED A VERY STRONG CAP CENTERED AROUND 750 MB AT TOP...WITH A SOMEWHAT WEAKER BUT STILL EFFECTIVE CAP AT OAX. AS THE 850 MB WARM FRONT CONTINUES TO LIFT NORTHWARD...AS SHOWN BY PROFILERS...MID TEENS 850 DEW POINTS WILL PUSH INTO THE AREA OVERNIGHT. THE MESOETA INDICATES THAT THE CAP WILL WEAKEN GREATLY BY 09Z WITH AN MCS DEVELOPING IN SOUTHEAST NEBRASKA. THIS SEEMS UNLIKELY GIVEN THE STRENGTH OF THE CAP. WILL LEAN TOWARD THE RUC SOLUTION OF THE CAP WEAKENING MORE IN THE NORTH. HI PWS ALSO INDICATE HEAVY RAIN POSSIBILITY IF THE CAP DOES BREAK...BUT THIS WOULD BE WELCOME IN MOST AREAS. SEVERE THREAT FOR TOMORROW APPEARS TO REMAIN INTACT...BUT UPDATED THE SOUTHEAST FOR LOWER POPS BOTH TONIGHT AND WED MORNING...AND MADE MINOR ADJUSTMENTS ELSEWHERE. .OMA...NONE POLLACK ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTH PLATTE NE 113 PM CDT TUE MAY 16 2000 FORECAST CHALLENGE WILL BE CONVECTION TONIGHT AND WEDNESDAY... RUC NAILED THIS MORNING/S SHOWER DEVELOPMENT IN LOUP COUNTY ALONG A WEAK SURFACE TROUGH EVIDENCED BY SURFACE ANALYSIS EXTENDING FROM OGA TO ONL. PRECIP DID NOT EXPAND...HOWEVER...AS RUC INDICATED IT WOULD INITIALLY. LATEST RUC HAS REFLECTED DRIER TREND. STRONG EAST SURFACE WINDS ACROSS SOUTHERN NEB INDICATE THAT WARM FRONT MAY STILL BE TO THE SOUTH IN NORTHERN KANSAS. DEWPOINTS CONTINUE TO GRADUALLY RISE...WITH 61 DEWPOINT ALREADY AS FAR NORTH AS HLC. NGM TEMPERATURE GUIDANCE WAS A BUST THE MOMENT IT CAME IN THIS MORNING. LBF WAS AT 73 ALREADY AT 15Z WITH GOOD MIXING...BUT FWC HAD US UP TO ONLY 71 BY 18Z. ETA IS A LITTLE BETTER WITH 18Z TEMP PROGGED AT 78 TO 79 WITH A DEWPOINT OF 57. ETA HAS GOOD RUN TO RUN CONSISTENCY ALSO. NGM SHOWING USUAL NORTHWARD BIAS IN PLACING THE LOW THROUGH PERIOD UNTIL 12Z THURSDAY WHEN NGM AND ETA COME TOGETHER AGAIN. AVN PLACEMENT IS BETWEEN ETA AND NGM...AND PREFER A BLEND OF THESE TWO FOR FORECAST. IF 7H WARM FRONT FORECAST PLACEMENT VERIFIES...THEN IT APPEARS 700MB CAP WILL BE TOO WARM IN THE SOUTHERN ZONES...BUT NOT IN THE NORTHERN ZONES FOR CONVECTION. MODELS APPEAR TO AGREE ON THIS SOLUTION...KEEPING LBF DRY. ETA-DERIVED VTN SOUNDING INDICATES GOOD PARAMETERS FOR POTENTIALLY SEVERE STORMS BETWEEN 00 AND 06Z WED...PERHAPS TORNADIC...BASED ON HODOGRAPH. STORMS THAT DEVELOP SHOULD BE PRETTY SLOW MOVERS...AND PW AROUND 1 INCH. LATEST ETA/S INDICATE CONVECTION STARTING ALONG THE DRY LINE AT 00Z FROM DDC THROUGH NORTHEAST CO TO EAST CENTRAL WY...WITH ANOTHER AREA INITIATING AT THAT SAME TIME IN SOUTHWEST SOUTH DAKOTA...ASSOCIATED WITH VORT MAX AT 5H. BY 03Z PRECIP HAS EXPANDED TO INCLUDE MUCH OF THE PANHANDLE (EXCEPT NEAR SNY) INTO WESTERN HALF OF CHERRY COUNTY. IF 7H LOW TRENDS FARTHER SOUTH...THEN CONVECTION WILL BE POSSIBLE IN LBF TO OGA AREA WITH COOLER TEMPS ALOFT. FROM 06Z ON...JUST NORTH OF THE WARM FRONT. THINK THAT POPS ARE WARRANTED OVER ENTIRE CWA...WITH LOWER ONES FOR SOUTHERN TIER DUE TO UNCERTAINTY OF CAP. THIS IS IN LINE WITH PREVIOUS FORECAST AS WELL. AM ANTICIPATING SPC TO DROP A WATCH BOX WHICH WILL LIKELY COVER NORTHERN HALF OF CWA BY 00Z OR SO (PROBABLY A TOR)...DEPENDING ON WHEN THINGS FIRE. FOR WED...ETA SHOWS SOME LINGERING SHOWERS FOR NORTHERN ZONES WEDNESDAY MORNING (12Z.) LOW IS POSITIONED JUST SOUTHEAST OF MCK IN KS AT THAT TIME...THEN REDEVELOPS FURTHER WEST IN NORTHEAST COLORADO BY 15Z WED IN RESPONSE TO UPPER LEVEL LOW MOVING OUT ACROSS CENTRAL CO...WITH WARM FRONT EXTENDING FROM SOUTH OF MCK... NORTHEAST TO LINCOLN NEB. AVN SHOWS IT SLIGHTLY FARTHER NORTH. AVN SHOWS LARGE (AND PROBABLY SOMEWHAT OVERDONE) AREA OF PRECIP ACROSS ALL BUT EXTREME SOUTHWEST NEBRASKA AT 12Z. AS SURFACE LOW CONTINUES TO DEEPEN OVER NORTHEAST CO DURING THE DAY...PRECIP BEGINS TO SPREAD SOUTH AS IT WRAPS AROUND THE LOW. ETA SHOWS SURFACE LOW FARTHER EAST ALONG KS/NEB BORDER. PLACEMENT OF THE LOW WILL BE CRUCIAL TO POSSIBLE SEVERE WEATHER WEDNESDAY AFTERNOON. AVN SHOWS TRIPLE POINT VERY NEAR LBF AT 00Z THURSDAY. DAY 2 OUTLOOK PUTS LBF AND THEDFORD IN THE MODERATE RISK...AND AREAS EAST ALONG THE FRONT. THIS APPEARS TO BE A PRETTY GOOD BET. WRAP AROUND SHOWERS COVER MOST OF FA THROUGH THURSDAY...FINALLY EXITING BY MIDNIGHT (06Z) FRIDAY AS SURFACE HIGH BUILDS IN. EXTENDED...MRF IN PRETTY GOOD AGREEMENT WITH LATEST UKMO. ECMWF HAS SIMILAR PATTERN BUT ABOUT A DAY FASTER THAN MRF AND UKMO. PREFER MRF AND UKMO SOLUTION FOR TIMING FEATURES. FRI AND SAT LOOK DRY AS MOST ACTIVITY STAYS TO THE SOUTH AND WEST WITH SURFACE HIGH PRESSURE OVER NEBRASKA FRIDAY. LEE SIDE TROF BEGINS TO DEVELOP SATURDAY...BUT LITTLE OR NOT LIFT UNTIL SUNDAY AT THE EARLIEST. SUNDAY...COLD FRONT TRAILING FROM LOW IN CANADA DRAGS ITS WAY EAST ACROSS NEBRASKA EXTENDING FROM OGA TO VTN AT 12Z...MOVING TO OMA BY 00Z. LOOKS LIKE BEST CHANCES FOR ANY PRECIP WOULD NOT BE UNTIL AFTERNOON SOUTH AND EAST OF A LINE FROM LBF THROUGH BBW TO ANW AND ONL. WILL INTRODUCE SLIGHT CHANCE FOR THOSE AREAS SUNDAY. WORDING IT AS SLIGHT DUE TO UNCERTAINTY OF TIMING. .LBF...NONE SLM ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BUFFALO NY 328 PM EDT TUE MAY 16 2000 RADAR MOSAIC SHOWS AREA OF PRECIP OVR LWR MI OHIO AND IND WEAKENING AS IT MOVES EAST INTO DRIER AIR ESPCLY ON NORTHERN PTN. RUC SEEMS TO BE OVERDOING NORTHERN PTN OF PRECIP OVR LK ONT THIS EVENING. WILL MENTION SPRINKLES EAST OF LK ONT AND OVR THE IAG FRONTIER AND A 30 POP THIS EVE OVR THE WESTERN SOUTHERN TIER BUT KEEP FINGER LKS REGION DRY OVRNGT. WEDGE OF DRIER AIR MOVES IN OVR THE AREA DURING WED. WILL DROP MENTION OF SHWR. WED NGT WARM FRNT MOVES NE WITH GOOD ISENTROPIC LIFT AND STRNG 700VV OVR THE REGION AFT 06Z. WILL GO WITH LKLY POPS AFT MIDNGT AND A CHANCE EAST OF LAKE ONTARIO. PROFILES SHOW STRNG LOW LVL JET AS WELL LTR WED NGT ESPCLY NR NY-PA BORDER. MENTIONED BREEZY OVR HILLS OF SOUTHERN TIER. ETA THE FASTEST WITH MOVEMENT OF COLD FRNT INTO WNY BY THU MRNG WITH AVN MOVING IT THROUGH THU AFTN. WILL GO WITH COMPROMISE SOLUTION. CAT POPS LOOK GOOD FOR THE REGION ON THU. GUID TEMPS CLOSE AND GENLY FOLLOWED. WRKZONES AVBL UNDER BUFADMBUF. .BUF...NONE. JJP ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 950 PM EDT TUE MAY 16 2000 DISC: LATEST LOOK FROM MESO ETA AND RUC2 COMPOSITE SUPPORT THE SHOWERS IN THE FORECAST BUT THEY MAY TAKE SOME TIME ARRIVING. VORT MAX MOVING THRU WATER VAPOR IMAG AT 30KT. 95% MEAN RH AHEAD OF VORT MAX OVER WVA INTO SW PA WILL MAKE IT ACROSS THE MTNS. CAA AT 50H MAY BE ENUF TO SUPPORT SOME HEAVIER SHOWERS/TSTM EXTREME SRN END OF CFA BUT NOT QUITE TO THE COASTAL WATERS. WILL ADD MENTION OF A TSTM IN SRN ERN MD ZNS AND SRN DEL. ON THE MARINE...SCA MAY BE NEED ON THU. 88-D FROM OKX SHOWS WHAT LOOKS LIKE SEA RETURN. (POINTED OUT BE CO-WORKER BG). GOES SOUNDING DATA AT 01Z SHOWED LO LVL INVERSION AROUND 900MB. AIR TEMP AT AMBROSE 57 OVER 55 DEG WATER. DUCTING SHOWING SOME SEA RETURN LOOKING SIM TO GRAV WAVES. PERIOD OF WAVES AT AMROSE 4 SEC WITH STIFF SRLY WIND(ALTHO ELEVATED)WHILE IN THE OPEN WATER OF BUOY 44009 11 SECONDS. OTHERWISE...SEE YA AT 3 AM. .PHI...NONE. EBERWINE pa AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA NATIONAL WEATHER SERVICE ABERDEEN SD 330 PM CDT TUE MAY 16 2000 THE LATEST MSAS ANALYSIS SHOWS SFC LOW PRES OVER S WY LATE THIS AFTN. ALL 3 MDLS SHOW THIS LOW PRES MOVG E ONTO THE PLAINS TONIGHT AND DEEPENING QUITE RAPIDLY THRU THE DAY ON WED. FOR TONIGHT...THE MDLS...INCLUDING THE RUC...SHOW S/W ENERGY AND WAA LIFT AFFECTING THE CWA LATER THIS EVENING. PLENTY OF MOISTURE AND INSTABILITY SHOULD BE AROUND THROUGH THIS EVENING AND ALSO BE ADVECTED IN ON THE WAA WINDS THROUGH THE NIGHT. THE MDLS DONT INDICATE VERY WELL THE NORTHERN EXTENT OF THIS INSTABILITY. SATELLITE DERIVED PRODUCTS SHOW CAPES OVER 3000 J/KG ACROSS C AND NC SD LATE THIS AFTN. THEREFORE ...WITH THE LIFT MOVG IN FROM THE SW...EXPECT SCT TO NMRS SHRAS AND TSRAS TO DEVELOP AND MOVE NE ACROSS THE ABR CWA THROUGH THE NIGHT. ALSO...E TO NE WINDS WILL INCREASE AS THE SFC PRES GRAD TIGHTENS UP TONIGHT. WITH INCREASING MEAN RH...CLOUDS WILL ALSO INCREASE THROUGH THIS EVENING. WITH THE CLOUD COVER...THE WINDS STAYING UP AND DWPTS IN THE LOWER TO MID 50S...TEMPS WILL NOT FALL OFF TOO FAR TONIGHT. FOR WED...SHRAS AND TSRAS WILL CONTINUE TO BE LIKELY THROUGH MOST OF THE MRNG AS S/W AND WAA LIFT WEAKENS. OTHERWISE...IT WILL BE CLOUDY AND COOLER THAN TODAY AS BIG SFC LOW MOVES INTO S NEB AND DEEPENS. THIS WILL BRING VERY WINDY CONDITIONS ACROSS THE CWA. LIKE THE AVN AND ETA MDLS ON THE TRACK OF THE SFC LOW THROUGH THIS FORECAST. FOR WED NIGHT AND THURS...SFC LOW MOVES E AND SE AND WEAKENS QUITE A BIT BY 00Z FRI. WIDESPREAD RAIN ACROSS THE SOUTHERN PART OF THE CWA WILL OCCUR WED NIGHT THROUGH THURS MRNG AS STRONG WAA AND UPPER DYNAMICS AFFECT THE CWA. THE N PART OF THE CWA FROM MBG TO ABR TO ETH WILL HAVE A LESSER CHC OF RAIN DUE TO THE LOCATION OF THE LOW AND BEST LIFT. IT SHOULD REMAIN WINDY THROUGH WED NIGHT AND MUCH OF THURS. SFC HIGH PRES...SUBSIDENCE AND DRIER AIR WILL END THE RAIN FROM NW TO SE ACROSS THE CWA ON THURS WITH SKIES BCMG P/C ACROSS THE N PART OF THE CWA. WHERE THE SUN COMES OUT ACROSS THE N AND C...THE TEMPS WILL BE HIGHER. WENT GENERALLY HIGHER ON POPS THAN GUID THROUGH THIS FORECAST AND LOWER ON DAYTIME HIGHS AND HIGHER ON NIGHTTIME LOWS. ...EXTENDED DISCUSSION... THERE IS VERY LITTLE AGREEMENT IN THE EXTENDED MODELS IN THE UPPER LEVELS. ALL THREE HAVE AN UPPER TROUGH ALONG THE WEST COAST BY THURSDAY EVENING. THE ECMWF KEEPS THE TROUGH ALONG THE COAST AND DIGS IT DEEPER OVER THE NEXT THREE DAYS. THE MRF AND UKMO MOVE THE TROUGH ON EAST. THE UKMO MOVES THE TROUGH EAST MUCH TOO FAST WHILE THE MRF SEEMS MORE REASONABLE. AT THE SURFACE...ALL THREE HAVE A SURFACE TROUGH ALONG THE NORTHERN ROCKIES AND A SURFACE HIGH OVER THE UPPER MISSISSIPPI RIVER VALLEY. AGAIN...THE UKMO SEEMS TO BE MOVING THE SURFACE TROUGH AND HIGH TOO FAST TO THE EAST. WITH THESE SCENARIOS...WILL USE THE MRF AS THE MODEL OF CHOICE BUT IT TOO WILL NEED SOME ADJUSTMENTS. HIGH PRESSURE OVER THE AREA FRIDAY AND MOST OF SATURDAY WILL BRING MOSTLY DRY WEATHER CONDITIONS. WITH THE SURFACE TROUGH MOVING INTO SOUTH DAKOTA SATURDAY AFTERNOON AND INTO MINNESOTA BY SUNDAY EVENING...ENOUGH LIFT AND MOISTURE WILL BE AVAILABLE FOR SOME SHOWERS. TEMPS EXPECTED TO BE AROUND NORMAL ON FRIDAY. BUT WITH WAA JUST AHEAD OF THE TROUGH...TEMPS SHOULD WARM UP ABOUT 5 TO 10 DEGREES BY SUNDAY. .ABR...NONE MOHR/SALMONS sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 255 PM CDT TUE MAY 16 2000 FORECAST QUANDARIES...TIMING/AMOUNT PCPN ON WED...TEMPS. CURRENT ASOS/AWOS OBSERVATIONS AND LAPS/SURFACE HAND ANALYSES SHOWING CWA UNDER WEAK SURFACE RIDGING INFLUENCES WITH 15-25 DEGREE TEMPERATURE/DEWPOINT SPREADS EXPERIENCED IN SOUTHERLY WIND FLOW. LATEST SATELLITE IMAGERY AND RUC/UPPER AIR CHART DEPICTIONS ILLUSTRATING UPPER LEVEL MOISTURE ADVECTION ACROSS REGION. THIS ADVECTION PATTERN HAS DEVELOPED AS MOISTURE MOVES AROUND THE PERIPHERY OF AN UPPER LEVEL RIDGING PATTERN PRESENTLY ACROSS THE CENTRAL U.S...IN PROGRESSIVE NWLY FLOW. OF PARTICULAR NOTE...A SURFACE WARM FRONT POSITIONED FROM OK SEWD INTO SOUTHERN LA. 12Z MON REGIONAL MODEL INITIALIZATIONS AND EXPECTED EVOLUTION THROUGH 00Z FRI IN GENERAL AGREEMENT. MODELS BRING SURFACE WARM FRONT INTO AREA BY 18Z TUE AND THEN RETROGRADE SWLY. VERTICALLY STACKED LOW PRESSURE SYSTEM OVER EASTERN NV WILL "MARCH" EAST WITH MAX UPPER LEVEL RIDGING OVER CWA BY 00Z THU... WITH DEVELOPING SWLY FLOW ACROSS REGION AS LOW PRESSURE SYSTEM MOVES INTO THE MIDWEST BY 00Z FRI. AS POINTED OUT BY LATEST MODEL DIAGNOSTIC DISCUSSION...A MORE SOUTHERLY ETA POSITION LIKED DUE TO ITS PREVIOUS VERIFICATION RESULTS. QUESTIONING ALSO CENTER AROUND CONFIDENCE FACTOR IN "DETAILS" OF MODEL ANALYSES. LOOK FOR AN INCREASE IN PERIPHERY CLOUDINESS AS RIDGE MOVES EASTWARD AND WARM FRONT APPROACHES FROM THE SW. NUMERICAL MODEL GUIDANCE PRODUCING NO POPS...BUT BELIEVE THAT SCATTERED SHOWERS ACTIVITY WILL INITIATE ACROSS REGION AFTER MIDNIGHT...WITH BEST CHANCE OF TS DEVELOPMENT WESTERN PORTIONS EARLY MORNING HOURS WEST TO MID MORNING HOURS EAST. DEVELOPING RIDGING INFLUENCES WILL LEAD TO AN OVERALL DECREASE IN CLOUDINESS WITH PARTLY SUNNY SKIES DURING THE AFTERNOON HOURS ON THU. MODEL RH TRENDS CONTINUE TO SUPPORT PARTLY CLOUDY SKIES WED NIGHT AND INTO THE DAY ON THURSDAY. LOOK FOR INCREASING CLOUDINESS OVER WESTERN PORTIONS OF REGION ON THURSDAY DUE TO THE APPROACHING LOW PRESSURE SYSTEM. EXTENDED...LOOK FOR SURFACE/UPPER LEVEL LOW PATTERN TO MOVE OUT OF THE MIDWEST AFTER 00Z FRI AND APPROACH THE OHIO VALLEY REGION BY 12Z FRI...PROVIDING FOR A CHANCE OF SHOWER AND THUNDERSTORM ACTIVITY THROUGH FRI. MRF ZONAL FLOW PATTERN THROUGH 00Z MON SEEM TO SUPPORT VARIABLE SKY CONDITIONS. TEMPS...INCREASED CLOUD COVER WILL SUPPORT WARMER OVERNIGHT LOWS THAN PREVIOUS NIGHTS. NGM MOS NUMBERS MOST REPRESENTATIVE OF SITUATION AND WILL TREND ACCORDINGLY. NGM MOS TRENDING TOO WARM ON HIGHS AS OF LATE...AND QUESTION VALIDITY OF HIGHS AROUND 90 BNA ON WED. AVN FAN VALUES SEEM MORE IN LINE WITH REGIONAL EXPECTED HIGH TEMPERATURES. WILL GO WITH AN NGM/AVN COMPROMISE ON HIGH TEMPERATURES FOR THU. PRELIMINARY NUMBERS FOR COORDINATION PURPOSES ONLY... BNA 061/085/063/085 3301 CSV 055/082/060/083 3300 .BNA...NONE. 14 JBW tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 826 PM EDT TUE MAY 16 2000 RELEASED EVENING ZONE UPDATE EARLY TO COVER THE WIDESPREAD SPRINKLES AND VERY LIGHT RAIN FALLING FROM THE ADIRONDACKS THROUGH WESTERN VERMONT. MOISTURE SEEMS TO HAVE SURGED IN AT MID LEVELS FROM THE EASTERN LAKES BUT IS ALREADY SLIPPING SEWRD. THE COMPLICATION IS THAT THE RUC AND MESOETA SUGGEST A RATHER SGFNT LOOKING VORT TROF WILL NOT PASS IN THE NORTHWEST FLOW UNTIL THE EARLY MORNING HOURS. THIS COULD KEEP THE SPRINKLES OCCURRING AND DELAY CLEARING UNTIL THE PREDAWN HOURS IN SOUTHERN AND ERN PTN OF THE FCST AREA. THE UPDATE FEATURES A MENTION OF SPRINKLES THROUGH MIDNIGHT EVERYWHERE EXCEPT THE ST LAWRENCE VALLEY. WITH MORE CLOUDS... RAISED THE MIN TEMPS A COUPLE DEGREES IN VT. INCREASED WINDS TO 10 MPH MOST AREAS BEFORE BECOMING LIGHT TOWARD MORNING IN NRN NY. WITH SHORT RANGE MDLS NOW SHOWING GOOD DRYING AND NVA FOR WEDNESDAY...CHANGED SKY FCST TO MOSTLY SUNNY ALL AREAS. .BTV...NONE. BELL vt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 955 PM EDT TUE MAY 16 2000 TOUGH UPDATE. SCATTERED SHWRS/TSTMS FORMING ALONG SFC BOUNDARY FROM CNTRL IN SEWD THRU SRN OH INTO SRN HLF OF WV...WHICH APPARENTLY REPRESENTS INITIAL SURGE OF DEEPER MOISTURE. BOUNDARY WILL LIKLEY SHIFT SLOWLY NORTHEASTWARD OVERNIGHT...BUT WILL CONVECTION CONTINUE? I WOULD HAVE TO SAY YES WITH THE TREND OF CONVECTION TO SHIFT TO THE EAST/NORTHEAST. MESOETA/RUC SHOW THIS BOUNDARY WITH SOME WARM ADVECTION TO CONTINUE AND SHIFT NORTHEASTWARD...AND WE ARE IN FAVORABLE REGION OF AN UPPER JET. BOTH OF THESE SUPPORTING FEATURES WILL EXIT EARLY WEDNESDAY MORNING...SO FCST ON WED STILL LOOKS GOOD. .RLX... WV...NONE. VA...NONE. KY...NONE. OH...NONE. .END / JMV wv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 240 AM CDT WED MAY 17 2000 LATEST RUC/ETA MODEL DATA INDICATE SE MISSOURI IS ON THE NOSE OF 850 MB 40 TO 50 KNOT SOUTHWESTERLY LOW LEVEL JET. ASSOCIATED LOW LEVEL CONVERGENCE AND DESTABILIZATION ARE RESULTING IN THE DEVELOPMENT OF SCATTERED ELEVATED CONVECTION. AS OF 07Z...IR SATELLITE LOOPS SHOW CLOUD TOP COOLING TAKING PLACE OVER PORTIONS OF MISSOURI. LIGHTNING DETECTION NETWORK STARTING TO SHOW NEW STRIKES OVER SE MISSOURI. ACTIVITY SHOULD CONTINUE TO INCREASE NEXT FEW HOURS IN ASSOCIATION WITH THE NOCTURNAL LOW LEVEL JET. WILL KEEP LOW POPS IN ALL ZONES THROUGH THIS MORNING. ACROSS NORTHERN ZONES...WILL KEEP POPS ALL DAY AS PRIMARY SURFACE WARM FRONT WILL BE IN VICINITY OF I-70 MUCH OF THE DAY. ACROSS FAR WEST KENTUCKY AND SE MISSOURI...MODELS INDICATE THE AFTERNOON SHOULD BE DRY AS MID LEVEL TEMPS WARM AND ELEVATED INSTABILITY DECREASES. ETA REALLY CRANKS UP A LOW LEVEL JET OVER THE FA TONIGHT...PERHAPS A LITTLE OVERDONE. HOWEVER...BEST FOCUS FOR CONVECTION WILL SHIFT INTO THE GREAT LAKES REGION NEAR THE NOSE OF THE LOW LEVEL JET AND SURFACE WARM FRONT. STRONGEST UPPER SUPPORT WILL BE WELL TO THE NORTH AND WEST OF THE FA. DRY FORECAST CONTINUES FOR THURSDAY IN LIGHT OF THE STRONG CONVECTIVE INHIBITION PROGS SHOWN BY THE ETA. 700 MB THERMAL RIDGE IS PROGGED TO PASS OVER THE FA DURING THE AFTERNOON. THIS SHOULD KEEP MOST OF THE CONVECTION CONFINED TO AREAS OF PRIME FORCING. EXPECT CHANCE OF STORMS TO INCREASE THURSDAY NIGHT AS SURFACE LOW AND COLD FRONT ENTER THE MID MISSISSIPPI VALLEY. WILL MAKE FEW IF ANY CHANGES TO TEMPS...AS THEY ARE IN GOOD AGREEMENT WITH MOS GUIDANCE AND APPEAR REASONABLE. WINDS WILL BE RATHER STRONG AND GUSTY EACH AFTERNOON DURING TIME OF MAXIMUM DIURNAL MIXING. .PAH...NONE. MY ky AREA FORECAST DISCUSSION...CORRECT DYR LINE MOVEMENT PARA 3 NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 230 AM CDT WED MAY 17 2000 CAP CONTINUES TO INHIBIT ANY DEVELOPMENT OF THUNDERSTORMS INTO EASTERN NEBRASKA. ONE WIND SHIFT...WARM FRONT MOVING NORTH THROUGH NORTHEAST NEBRASKA. MORE THAN ANYTHING THIS IS REFLECTED IN HIGHER DEW POINTS AND STRATUS DECK. THIS DECK IS SHOWING VERY NICELY ON RADAR AS A SERIES OF GRAVITY WAVES IN THE BOUNDARY MOVING NORTHEAST. MORE DISTINCT SURFACE BOUNDARY EXTENDS FROM LOW OVER NORTHEAST COLORADO ACROSS NORTHERN KANSAS. TO THE SOUTH EVEN HIGHER DEWPOINTS ARE ACCOMPANIED BY LOSS OF LOW CLOUDS WITHOUT FRONTAL LIFT. SATELLITE SHOWS RATHER DISTINCT TROUGH MOVING EAST INTO WESTERN NEW MEXICO...BUCKLING THE JET EASTWARD. ALL MODELS ARE IN AGREEMENT THAT THIS TROUGH WILL PULL THE UPPER CIRCULATION INTO THE WESTERN HIGH PLAINS THIS MORNING. ALL THREE MODELS HAD THE SURFACE CIRCULATION IN NORTHWEST KANSAS AT 06Z...EAST OF THE ACTUAL POSITION IN NORTHEAST COLORADO. THE 06Z RUC ADAPTED TO THIS ALTHOUGH IT REMAINS A LITTLE SUSPECT AS IS THE ETA. ALL THREE MODELS HAVE A SIMILAR SOLUTION...THE WARM FRONT TRANSITIONS TO THE PLATTE RIVER OR SLIGHTLY NORTH...BUT THE DRY LINE SWINGS CYCLONICALLY AROUND THE SURFACE LOW...INFLUENCING THE WARM FRONT TO HOLD SOMEWHERE IN EASTERN NEBRASKA...BUT WITH RENEWED MOISTURE CONVERGENCE IN SOUTHEAST NEBRASKA AND EAST INTO SOUTHWEST IOWA. I HAVE NO STRONG PREFERENCE BETWEEN MODELS FOR NOW...EXCEPT THAT THE NGM HAS DROPPED ITS USUAL NORTH BIAS COMPARED TO THE OTHERS. IN ADDITION...THIS REMAINS A STRONG BAROCLINIC SYSTEM WHICH WOULD FAVOR THE AVN. CAPPING SHOULD CONTINUE TO BE A FACTOR IN SOUTHEAST NEBRASKA THIS MORNING...BUT WITH INCREASING MOISTURE CONVERGENCE AND WARM ADVECTION BY THIS AFTERNOON THIS WILL NOT LONGER BE THE CASE. AS A RESULT...THERE REMAINS SOME CHANCE OF THUNDERSTORM ACTIVITY THIS MORNING...STRONGLY FAVORING NORTHEAST NEBRASKA...BUT A MUCH GREATER THREAT FROM MID AFTERNOON UNTIL MIDNIGHT ACROSS THE ENTIRE CWA. I WOULD ALSO HAVE SOME PROBLEMS WITH THE POSSIBILITY OF HEAVY PRECIP...BUT RIGHT NOW THAT IS WHAT EVERYONE IS LOOKING FOR. AFTER THIS EVENING DRIER AND MORE STABLE CONDITIONS SHOULD PREVAIL TO THE SOUTH OF THE SURFACE CIRCULATION AS IT TRAVERSES INTO NORTHERN MISSOURI. TO THE NORTH THE AIRMASS SHOULD BE STABLE BUT WITH SUBSTANTIAL CLOUD COVER. TEMPS TODAY REACHING THE 70S IN THE NORTH BUT PROBABLY MID 80S IN THE COUNTIES BORDERING KANSAS. LOWS TONIGHT NEAR 50 AT NLG TO LOWER 60S AT FNB. COOLER THUS...ESPECIALLY IN NORTHEAST NEBRASKA. PROBABLY 60 AT NLG TO 75 AT FNB. .OMA...NONE POWERS ne AREA FORECAST DISCUSSION...CORRECTION FOR TYPO NATIONAL WEATHER SERVICE SACRAMENTO CA 840 AM PDT WED MAY 17 2000 STRATOCU DECK/RESIDUAL MOISTURE IS CONCENTRATED IN NRN SAN JOAQUIN VALLEY THIS MORNING AS NW FLOW HAS BANKED CLOUDS AGAINST MOTHERLODE. TIMING OF THIS ERODING WILL BE THE MAIN PROBLEM OF THE DAY AS CLOUDS MAY BECOME TRAPPED UNDER SUBSIDENCE INVERSION. 12Z ETA SHOWING 80 PERCENT H85 MOISTURE LINGERING IN THIS REGION THRU 00Z. EXPECT CLOUDS TO BREAK UP OVER MUCH OF THE SJ VALLEY BY MIDDAY BUT MAY REMAIN UP IN THE LOWER MOTHERLODE. 12Z RUC ALSO SUPPORTS THIS IDEA. WATER VAPOR SHOWS SHEARED OUT TROF ENTERING THE PACNW...CIRRUS SHIELD ASSOCIATED WITH THIS IS MOSTLY ON THE EAST SIDE OF CWA NOW. SATELLITE SHOWS LITTLE UPSTREAM CIRRUS. WILL UPDATE ZFP TO TWEAK OR REMOVE CLOUD WORDING. KOAK SOUNDING SHOWS MAJOR WARMING ABOVE 800-MB AS THE STUBBORN UPPER LOW IS NOW WELL EAST OF THE REGION. LINGERING EFFECTS OF THE LOW WILL BE SOME WEAK INSTABILITY OVER THE SIERNEV BUT NOT LOOKING FOR CONVECTIVE PRECIP. OTHERWISE PACIFIC RIDGING WILL DOMINATE OUR WEATHER THROUGH THE FORECAST PERIOD. STRENGTHENING SUBSIDENCE INVERSION IS SEEN DOWN TO 5KFT TODAY ON BUFKIT HOURLY SOUNDINGS. WEAK W-E PRESSURE GRADIENT WILL BECOME MORE N-S TONIGHT AND TOMORROW AS INVERTED TROF SETS UP ON THE COAST. H85 TEMPS UP TO 12C TODAY AND 16C BY THURSDAY WILL RESULT IN SIGNIFICANT WARMING. WEAK WAVES WILL CONTINUE TO SPILL SOME CIRRUS OVER THE CWA THRU FRIDAY. ALL LONG RANGE MODELS IN GENERAL AGREEMENT THROUGH MONDAY. A WEAK WAVE IS PROGGED TO CLIP THE SIERNEV OVER THE WEEKEND. THIS SHOULD DO LITTLE TO OUR WARMING TREND BUT MAY BE ENOUGH TO TRIGGER A THUNDERSTORM OVER THE CREST. 582DM H5 HEIGHTS ON FRIDAY AND SATURDAY CLIMB TO 588DM BY MONDAY. GIVEN MODEL CONSISTENCY WITH SYNOPTIC PATTERN WILL LIKELY BUMP TEMPS UP IN THE EXTENDED INTO 90S. IF PATTERN VERIFIES SOME LOCALES COULD BE APPROACHING 100F. .STO...NONE. TARDY ca AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GOODLAND KS 844 AM MDT WED MAY 17 2000 LOTS GOING ON THIS MORNING. LATEST RUC/ETA WIND FORECASTS ALL SHOWING WINDS INCREASING RAPIDLY THIS AFTERNOON TO ADVISORY CRITERIA. SINCE I HAD TO UPDATE THE ZONES TO ALLOW THE FOG ADVISORY TO EXPIRE...I WENT AHEAD AND ISSUED THE ADVISORY AT THE SAME TIME. ALSO...DROPPED AFTERNOON HIGHS ABOUT 5 DEGREES OR SO BASED ON LATEST RUC FORECASTS AND WRAPAROUND CLOUDINESS. ALSO...WITH SUCH HIGH DEWPOINTS TO OUR EAST...IT WILL SLOW THE WARMING PROCESS A BIT. LATER UPDATES MAY BE NEEDED. .GLD...WIND ADVISORY IN EFFECT UNTIL 7 PM MDT (8 PM CDT) FOR CO ZONES 091 AND 092, KS ZONES 002-004...013-016...027-028...AND 041- 042. THEDE ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTH PLATTE NE 1001 AM CDT WED MAY 17 2000 ELEVATED CONVECTION POSSIBLY TAKING PLACE ACROSS PORTIONS OF THE CWA AT THIS TIME. BAND OF MID LEVEL CLOUDS THAT PASSED OVER VTN PRODUCED A TENTH OF AN INCH OF RAIN THE PAST HOUR. APPEARS TO BE ALONG A BOUNDARY MOVING SLOWLY SOUTHEAST...EXTENDING FROM NEAR OSHKOSH IN GARDEN COUNTY TO NEAR AINSWORTH. WILL UPDATE FOR CATEGORICAL WORDING OF SHOWERS. RUC BL RH APPEARS TO BE DOING THE BEST JOB SO FAR WITH THE LOW LEVEL MOISTURE OVER THE AREA...BUT KEEPS NORTHERN HALF OF FA IN THE SOUP THROUGH THE DAY. NEW ETA HAS IT LIFTING OUT BY 18Z...AND IN AREAS WHERE THERE ARE NO CLOUDS ABOVE THE FOG AND DRIZZLE...AND THERE ARE SOUTHERLY WINDS...THIS MAY HAPPEN. SOUTHERN EDGE APPEARS TO BE LIFTING SOME PER VIS SAT PIX. THINK THAT AS LONG AS NORTHERN ZONES CONTINUE TO HAVE NORTHEAST WIND...THAT WARM MOIST AIR FROM THE SOUTH WILL CONTINUE TO CONDENSE NORTH OF THE WARM FRONT...THUS KEEPING THE NORTHERN AREAS CLOUDY/FOGGY/DRIZZLY MOST OF THE DAY. THIS WOULD ALSO PRESUMABLY DECREASE THE THREAT OF SEVERE WEATHER (TORNADOES ANYWAY) THERE THIS AFTERNOON. WILL HAVE TO UPDATE BY AROUND NOON TO TAKE OUT MORNING WORDING. WILL ASSESS NEED FOR WIND ADVISORY...DEPENDING ON HOW THINGS BEGIN TO MIX...AND WILL LIKELY LOWER HIGH TEMPS A BIT ACROSS THE NORTH AS THEIR TEMPS WILL GO NOWHERE TODAY. PRELIMINARY EXTENDED DISCUSSION...MRF NOT LOOKING QUITE AS WELL ORGANIZED WITH SUNDAY SYSTEM AS PREVIOUS RUN...AND IT NOW BRINGS IN SOME PRECIP SATURDAY NIGHT TO SOUTHEAST FRINGE ZONES. PRECIP FIELDS LOOK INCONSISTENT WITH PROGS AS COLD FRONT TO CROSS THE STATE MONDAY NIGHT THROUGH TUESDAY. .LBF...NONE SLM ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 428 PM CDT WED MAY 17 2000 SCT SHWRS LOCATED OVR XTRM NW CWA ERLY THIS PM ALG NOSE OF JET STREAK AND SMALL POCKET OF DIVERGENCE AT 250 HPA BRANCHED OFF FM MAIN UPR TROPSPHERIC JET ENERGY. MAIN JET ENERGY LIFTING NWRD THRU ERN KS ATTM ALIGNED PARALLEL AND JUST W OF CTNL KS DRY LN. RUC HAS HANDLED THESE FEATURES WELL AND SVR CNVTN IGNITING LAST SVR HRS AHD OF MAIN JET ENERGY ACR S CNTL NE. AXIS OF 2000+ J/KG CAPES XTNDS INTO XTRM NW MO WHICH IS PRIMARY AREA OF CONCERN FOR CWA TNGT. HOWEVER MODEL DATA SUGGESTS STG HELICTY VALUES TAPERING OFF TO SE FM AREA WHERE CRNT TORNADIC STORMS FORMING SO MAIN SVR WX CONCERNS ATTM ARE HAIL AND STG WNDS FM PSBL LINEAR SQUALL LN DVLPMNT. DRY LN WILL TRY TO LIMP THRU WRN CWA LTR TNGT AND WITH MODEL TIME SECTS INDICATING DIFFERENTIAL ADVT THRU 0600 UTC THINK LAPSE RATES SHLD STEEPEN UP ENOUGH FOR PSBL SVR LN OF CNVTN. METIONED PSBL SVR IN ALL WRN ZNS. FTHR E SVR THREAT IS A BIT MORE AMBIGUOUS SO JUST KEPT CHC POPS FOR SHWRS/TSTMS. MODELS SUGGEST RMNS OF DRY LN BNDRY TO LINGER OVR FCST AREA ON THUR AND WITH UPR LO AXIS STILL TO W CNVTV THREAT TO RMN IN TACT. HOWEVER MODELS GRIDS HINT AT SOME MID/UPR TROPOSPHERIC WRMING AS CLOSED CIRCULAITON TRYS TO FILL SO LAPSE RATE MAY NOT BE STEEP ENOUGH FOR SVR CNVTN. MID CREW WILL HAVE TO RE-EVAUALTE. STAYED CLOSE TO INHERITED FCST REMAINDER OF FCST PRD INCLUDING XTND. IN XTND PRDS CONCERNED ABT PSBL HVY RN ACR NE CWA DEPENDING ON WHERE STG BAROLINIC ZN ESTABLISHES ITSELF. ..EAX... BODNER mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 250 PM CDT WED MAY 17 2000 FORECAST QUANDARIES...STRENGTH OF TS ACTIVITY ON FRI...TEMPS. CURRENT ASOS/AWOS OBSERVATIONS...REGIONAL SATELLITE AND MOSIAC RADAR IMAGERY...AND LAPS/SURFACE HAND ANALYSES SHOWING SHOWER ACTIVITY MOVING EASTWARD AS UPPER LEVEL RIDGING BEGINS TO AFFECT AREA WEATHER PATTERN. CWA/S SURFACE TEMPERATURE/DEWPOINT SPREADS THIS AFTERNOON STILL AVERAGING 5 TO 10 DEGREES UNDER CONTINUING SOUTHERLY FLOW AND GULF MOISTURE "TAP". A WIDE SWATH OF DEWPOINTS RANGING IN THE 60S NOTED FROM EASTERN TX TO CENTRAL IOWA. LATEST RUC/12Z UPPER AIR CHART DEPICTIONS SHOWING WINDS VEERING TO THE NW WITH HEIGHT AS RIDGE AXIS APPROACHES. OF PARTICULAR NOTE...UPPER LEVEL LOW/DIGGING TROUGH OVER THE EASTERN CO PLAINS. 12Z WED REGIONAL MODEL INITIALIZATIONS AND EXPECTED EVOLUTION THROUGH 00Z SAT IN GOOD AGREEMENT...WITH ETA THE BEST INITIALIZED WITH SURFACE LOW POSITIONED IN EASTERN CO. ETA SEEMS TO HAVE HANDLED WEATHER SCENARIOS WELL OVER THE LAST FEW RUNS AND WILL LEAN TOWARD ITS SOLUTION FOR THIS UPCOMING FORECAST PERIOD. AS UPPER LEVEL RIDGE APEX MOVES INTO THE AREA AND EASTWARD INTO THE ATLANTIC COASTAL REGION BY 00Z FRI...LOW PRESSURE SYSTEM WILL MOVE FORM EASTERN CO TO THE IOWA/MISSOURI BORDER REGION. THIS WILL KEEP CWA UNDER CONTINUING SOUTHERLY FLOW AND ATTACHMENT TO GULF MOISTURE "TAP". A DECREASE IN UPPER LEVEL MOISTURE WITH UPPER LEVEL RIDGING AFFECTS EXPECTED...BUT BELIEVE ENOUGH LOW AND MID LEVEL MOISTURE WILL BE AVAILABLE TO SUPPORT PARTLY CLOUDY SKIES THROUGH 00Z FRI. LOOK FOR SURFACE LOW TO MOVE INTO EASTERN IL BY 12Z FRI WITH UPPER LEVEL TROUGH DEVELOPING OVER THE MISSISSIPPI VALLEY REGION. WILL GO MOSTLY CLOUDY WEST AND MIDDLE WITH WIDELY SCATTERED SHOWERS AND THUNDERSTORMS. SURFACE LOW AND UPPER LEVEL TROUGH WILL MOVE ACROSS AREA ON FRI...WITH MODEL INSTABILITY PARAMETERS SHOWING THE POTENTIAL FOR AT LEAST SOME STRONG THUNDERSTORMS. WILL GO WITH A SCATTERED POPS RANGE WEST TO EAST ON FRIDAY...AND MORE IN LINE WITH AVN FAN VALUES. EXTENDED...WITH WEAK SURFACE RIDGING ACROSS REGION THROUGH 00Z TUE ...LOOK FOR SHORTWAVES IN ZONAL FLOW TO CONTINUE PROVIDING A CHANCE OF SHOWER/AND OR TS ACTIVITY...WITH MRF DEVELOPING UPPER LOW ACROSS NE GA BY 00Z TUE. TEMPS...NGM MOS TRENDING WELL ON LOWS AS OF LATE AND WILL TREND ACCORDINGLY. WITH BREEZY SOUTHERLY WIND FLOW...TEMPERATURES IN THE UPPER 80S REACHING TO AROUND 90 SOUTHERN PORTIONS POSSIBLE. WILL TREND TOWARD NGM MOS VALUES FOR HIGHS ON THU. NGM MOS/AVN FAN VALUES IN LINE FOR FRI HIGHS. THANKS FOR COORDINATION MEM PRELIMINARY NUMBERS FOR COORDINATION PURPOSES ONLY... BNA 064/087/066/082 1124 CSV 060/083/061/079 1113 .BNA...NONE. 14 JBW tn