Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/04/15


AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
836 AM PDT Sat May 2 2015 .Synopsis... Warm temperatures with a slight chance of mountain thunderstorms continuing through early next week. Cooler and possibly more unsettled weather will set in late next week. && .Discussion... A cooler start to the day today, especially from Fairfield westward, where there has been cool Delta flow. Temperatures overall around 2 to 8 degrees cooler than this time on Friday. Highs today are on track to be in the upper 80s over most of the Valley, perhaps reaching around 90 for a few spots like Redding and Modesto. Vallejo/Benicia are currently overcast with marine stratus, and may struggle to reach 70 this afternoon. The mountains should be quite mild, maybe a couple of degrees cooler than on Friday. Temperatures on Sunday overall should drop a few degrees as atmospheric heights lower a bit more. Still, temperatures will remain well above normal levels. Forecast is on track, no changes made. EK .Extended Discussion (Wednesday through Saturday) Mid range models in fairly good agreement now in digging upper low pressure system over Pacific Northwest southward into Northern California on Wednesday. Even with the cooling expected on Wednesday...daytime highs are still forecast to come in just above normal for early May. Enough moisture and instability with this system to justify slight threat of mountain thunderstorms Wednesday but valley is likely to remain dry. Models dig the low farther south on Thursday and all linger the low over the western U.S but differ on the details as would be expected with a close low. Conditions become more unstable Thursday as cooler air aloft moves into the region and shower/thunderstorm threat will likely become more widespread. At this time...ECMWF and GFS have low/trough axis east of Norcal which would make the thunderstorm threat a mainly mountain only feature. GEM model holds low center over Norcal which would bring a shower/thunderstorm threat to all areas of Norcal. For now GEM is the outlying model and less favored. All models move the low little on Friday so expect little change Friday from Thursday in overall weather. All extended models shift the low into the Great Basin by next Saturday bringing much more stable conditions to the north state although RAP around moisture could still bring a threat of showers to the Sierra and northern mountains. Daytime high temperatures should be on a slight climbing trend by the end of next week. && .Aviation... Generally VFR conditions the next 24 hours across interior Northern California. A few thunderstorms may form along the Sierra this afternoon and early evening. Winds generally below 15 knots except southwest 15 to 20 knots gusting to 30 kt through the Delta and locally gusty in vicinity of Sierra thunderstorms. EK && .STO Watches/Warnings/Advisories... None. && $$
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
345 AM PDT Sat May 2 2015 .Synopsis... Warm temperatures with a slight chance of mountain thunderstorms will continue through early next week. Cooler and possibly more unsettled weather will set in late next week. && .Discussion... Clear skies prevail across most of interior Northern California with dry westerly flow aloft. The marine layer has returned along the coast, although has deepened to only 1000 ft at Fort Ord. Even with a decent onshore push at this hour, we have only seen a modest amount of cooling across the interior. A bit of marine stratus has made it to the western Delta near Vallejo, but don`t expect it to push much farther inland by sunrise. Warm temperatures are expected to continue through the weekend, though the trend is a slow, gradually-cooling one. Highs today and Sunday across the Central Valley will be in the mid 80s to lower 90s, coolest near the Delta. Temperatures across the mountains should reach the 60s to 80s range. A few showers or thunderstorms will be possible again over the high Sierra and Lassen Park, but southwest flow aloft should quickly blow them east of the crest. Onshore flow should increase Monday into Tuesday as an upper trough moves through the Pacific Northwest. That should bring at least a bit more synoptic cooling and a stronger Delta Breeze. Temperatures are likely to remain above normal through the short term though. Dang .Extended Discussion (Wednesday through Saturday) Mid range models in fairly good agreement now in digging upper low pressure system over Pacific Northwest southward into Northern California on Wednesday. Even with the cooling expected on Wednesday...daytime highs are still forecast to come in just above normal for early May. Enough moisture and instability with this system to justify slight threat of mountain thunderstorms Wednesday but valley is likely to remain dry. Models dig the low farther south on Thursday and all linger the low over the western U.S but differ on the details as would be expected with a close low. Conditions become more unstable Thursday as cooler air aloft moves into the region and shower/thunderstorm threat will likely become more widespread. At this time...ECMWF and GFS have low/trough axis east of Norcal which would make the thunderstorm threat a mainly mountain only feature. GEM model holds low center over Norcal which would bring a shower/thunderstorm threat to all areas of Norcal. For now GEM is the outlying model and less favored. All models move the low little on Friday so expect little change Friday from Thursday in overall weather. All extended models shift the low into the Great Basin by next Saturday bringing much more stable conditions to the north state although RAP around moisture could still bring a threat of showers to the Sierra and northern mountains. Daytime high temperatures should be on a slight climbing trend by the end of next week. && .Aviation... Generally VFR conditions the next 24 hours across interior Northern California. A few thunderstorms may form along the Sierra this afternoon and early evening. Winds generally below 15 knots except southwest 15 to 20 knots through the delta and gusty in vicinity of thundestorms. && .STO Watches/Warnings/Advisories... None. && $$
AREA FORECAST DISCUSSION
NWS PUEBLO CO
852 PM MDT SUN MAY 3 2015 .UPDATE... ISSUED AT 848 PM MDT SUN MAY 3 2015 BASED OFF TRENDS OF HRRR...RUC AND 00Z NAM...HAVE BUMPED UP POPS ALONG I-25 CORRIDOR.S MTNS REGION FOR LATER TONIGHT INTO EARLY TOMORROW MORNING. GUIDANCE SHOWING PRETTY GOOD UPSLOPE DEVELOPING LATER TONIGHT. THIS ALONG WITH THE 700 MB CIRC DEVELOPING OVER THE SE PLAINS TONIGHT AND THE GOOD LOWER LEVEL EASTERLY FLOW...SEE NO REASON TO GO AGAINST THE GUIDANCE. IF HRRR CONTINUES WITH THE PRECIP...WILL HAVE TO BUMP UP POPS IN A LATER FCST UPDATE. /HODANISH && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 234 PM MDT SUN MAY 3 2015 SHOWERS AND STORMS THAT HAVE DEVELOPED THIS AFTERNOON HAVE GENERALLY BE FAIRLY SLOW MOVING AND SHORT LIVED. ISOLATED TO SCATTERED SHOWERS AND TSTMS OVR THE AREA WL CONTINUE INTO THE EVENING HOURS...AND DECREASING TOWARD MIDNIGHT. A COLD FRONT WL MOVE SOUTH INTO THE SOUTHEAST PLAINS THIS EVENING...WITH THE NAM SHOWING IT REACHING THE SRN CO BORDER EARLY MON MORNING. BEHIND THE FRONT...SFC DEW POINTS INCREASE INTO THE 40S...AND LOW STRATUS IS FORECAST TO DEVELOP OVR NORTHERN EL PASO COUNTY BY MIDNIGHT AND THEN SPREADING SOUTHWARD OVERNIGHT. THE HRRR...NSSL WRF AND NAM CONTINUE TO SHOW PCPN BEHIND THE FRONT OVR EL PASO AND TELLER COUNTIES DURING THE LATE NIGHT HOURS...WITH MUCH OF THE REST OF THE FORECAST AREA BEING DRY. THE HRRR SPREADS PCPN SOUTHWARD INTO PUEBLO AND FREMONT COUNTIES AS WELL. ON MONDAY AN UPR LOW BECOME CENTERED OVR THE CA AND AZ BORDER WITH SOUTHERLY FLOW ALOFT OVR THE FORECAST AREA AHEAD OF THIS SYSTEM...DRAWING MSTR NORTHWARD. WITH MOIST LOW TO MID LEVEL SOUTHEASTERLY WINDS...KEEPING AFTERNOON SFC DEW POINTS ACRS THE SERN PLAINS IN THE MID40S TO LOWER 50S. MOST OF THE LOW STRATUS IS EXPECTED TO DISSIPATE BEFORE AFTERNOON. THE NAM SHOWS SHOWERS/TSTMS DEVELOPING IN THE MID MORNING HOURS OVR THE MTNS...ESPECIALLY ALONG THE CONTDVD...WHERE A SHORTWAVE TROF IS EXPECTED TO MOVE NORTHWARD THRU THE AREA. PCPN WL INCREASE ACRS THE MTNS BY MIDDAY AND WL SPREAD TO THE ADJACENT LOWER ELEVATIONS...AND THEN THROUGH THE AFTERNOON WL BECOME WIDESPREAD ACRS MOST OF THE FORECAST AREA. THERE WL BE THE POTENTIAL FOR LOCALIZED HEAVY RAIN. ALSO...PORTIONS OF THE SERN PLAINS COULD SEE ONE OR TWO MARGINALLY SEVERE STORMS IN THE AFTERNOON. HIGH TEMPS ON MON WILL BE COOLER THAN TODAY AND SHOULD GENERALLY BE JUST A LITTLE BELOW NORMAL. HIGH TEMPS IN THE SAN LUIS VALLEY SHOULD BE CLOSE TO NORMAL. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 234 PM MDT SUN MAY 3 2015 ...STORMY WEATHER THROUGH TUESDAY... MONDAY NIGHT...WILL SEE SEVERAL ONGOING ROUNDS OF PRECIP AND STORMS OVER THE AREA. THE STRONGEST OF THESE WILL LIKELY BE OVER THE ERN PLAINS...GENERALLY E OF KLHX...AND ANOTHER AREA OVER THE PALMER DVD. GIVEN THE ABUNDANT LLVL MOISTURE AND INCREASED SHEAR DUE TO BACKED LLVL FLOW...CANNOT RULE OUT A STRONG TO SVR STORM OR TWO ESPECIALLY IN THESE FAVORED AREAS. COULD SEE A BRIEF LULL IN THE PRECIP MON EVE BEFORE PRECIP COVERAGE INCREASES LATER MON NIGHT...IN BANDS OF CONVECTION ROTATING UP FROM THE SOUTH. WILL MAINTAIN ISOLD OR SLIGHT CHANCE OF TS OVERNIGHT ALONG WITH MORE WIDESPREAD LIKELY POPS ACROSS THE MTS AND PLAINS. ON TUE...THE UPPER LOW WILL MOVE INTO THE FOUR CORNERS REGION...THEN TRACK TO THE NE DURING THE DAY. TEMPS WILL BE COOLER...IN THE 60S FOR THE PLAINS...DUE TO WIDESPREAD CLOUDS AND PRECIP. IT LOOKS LIKE MUCH OF THE BEST PRECIP COVERAGE WILL BE TUE MORNING...ALTHOUGH EVEN IF THERE ARE ANY BREAKS IN THE SHOWERS AND STORMS...THEY SHOULD PICK UP AGAIN BY TUE AFTERNOON. SNOW LEVELS MON-TUE WILL BE PRETTY HIGH...BUT GIVEN THE AMOUNT OF QPF...COULD SEE SOME LOCAL SIGNIFICANT ACCUMS IN THE MTS OF SIX INCHES OR MORE...ESPECIALLY ABOVE 12000 FEET. SO...RECREATIONISTS SHOULD BE AWARE OF WINTER CONDITIONS FOR THE HIGH PEAKS. GIVEN ALL THE PRECIP...THE BL SHOULD BE PRETTY STABILIZED BY TUE SO SURFACE BASED CONVECTION LOOKS UNLIKELY. BUT...A STRONG STORM OR TWO CANNOT BE RULED OUT OVER THE AREA AS THE UPPER LOW MOVES THROUGH NRN CO. BY WED...SHOULD SEE THINGS WINDING DOWN AS THE FIRST UPPER LOW MOVES OFF INTO THE DAKOTAS AND NE. WILL STILL SEE SOME WRAP AROUND PRECIP OVER THE DVD AND NRN PORTIONS OF THE CWA. TEMPS SHOULD REBOUND NICELY BACK INTO THE 70S OVER THE PLAINS. THE NEXT SYSTEM WILL DROP SWD FROM THE PACNW ON WED...THEN CUTOFF OVER CA THU-SAT...AND SLOWLY MOVE TO THE NE OVER THE WEEKEND. GLOBAL MODELS ARE STILL IN GOOD AGREEMENT THAT THIS SYSTEM WILL TRACK TO OUR NORTH NEXT WEEKEND...ALTHOUGH LATEST RUNS HINT THAT THE TRACK MAY BE A BIT FARTHER SOUTH. STILL LOOKS LIKE MOST OF SE CO WILL BE STUCK IN THE DRY SW FLOW TO THE SOUTH OF THE LOW...BUT GIVEN THE UNCERTAINTIES WILL MAINTAIN POPS OVER THE AREA...ESPECIALLY FOR THE MTS. TEMPS WILL BE CONSIDERABLY LOWER WITH THIS SYSTEM...AS H7 TEMPS ARE MINUS THREE OR LOWER...SO SOME MTN SNOWS SEEM LIKE A GOOD BET. ROSE && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 234 PM MDT SUN MAY 3 2015 VFR CONDITIONS ARE EXPECTED AT THE TAF SITES UNTIL LATE TONIGHT. ISOLATED TO SCATTERED TSTMS MAY MOVE INTO THE VCNTY OF THE TAF SITES THIS EVENING WITH ERRATIC GUSTY WINDS BEING THE MAIN THREAT. LATE TONIGHT IT LOOKS LIKE AT KCOS AN MVFR OR IFR CIG WL DEVELOP AS LOW STRATUS DEVELOPS BEHIND A COLD FRONT. ISOLD SHOWERS AND TSTMS MAY ALSO CONTINUE AT KCOS INTO THE LATE NIGHT HOURS. KPUB COULD ALSO SEE SOME PCPN LATE TONIGHT AND MAYBE EVEN SEE SOME LOW STRATUS MOVE INTO THE VCNTY...HOWEVER CHANCES OF THIS OCCURRING ARE A BIT UNCERTAIN AT THIS TIME. THE LOW STRATUS IS FORECAST TO DISSIPATE BY MID TO LATE MORNING WITH VFR CONDITIONS EXPECTED AT THE TAF SITES ON MONDAY. SHOWERS AND TSTMS ARE ONCE AGAIN A POSSIBILITY AT THE TAF SITES...MAINLY IN THE AFTERNOON HOURS. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HODANISH SHORT TERM...28 LONG TERM...ROSE AVIATION...28
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1242 AM MDT SAT MAY 2 2015 .UPDATE... ISSUED AT 1242 AM MDT SAT MAY 2 2015 WITH CLEARING SKIES AND DECREASING DEWPOINT DEPRESSIONS OVER WELD COUNTY...AS WELL AS THE HRRR AND RAP HI RES MODELS SHOWING SOME VISIBILITY REDUCTIONS IN A FEW HOURS....HAVE ADDED SOME PATCHY FOG ALONG THE SOUTH PLATTE RIVER VALLEY IN WELD...MORGAN AND LOGAN COUNTIES THROUGH MID MORNING HOURS. UPDATE ISSUED AT 945 PM MDT FRI MAY 1 2015 MINOR UPDATES PLANNED AT THIS TIME. MAINLY SOME LINGERING SHOWERS THIS EVENING. WL GO WITH SHOWERS VS TSTMS IN THE GRIDS FOR THE REST OF THIS EVENING. UPDATE ISSUED AT 641 PM MDT FRI MAY 1 2015 THE FOCUS FOR THUNDERSTORMS HAS SHIFTED TO THE NORTH AND EAST OF DENVER FOR THE MOST PART SO HAVE STARTED TO BACK OFF THE POPS ESPECIALLY OVER THE WESTERN PART OF THE CWA. THE POPS MAY STILL BE A BIT OVERDONE SINCE THE HRRR HINTS AT SOME ADDITIONAL ACTIVITY OVER THE NEXT COUPLE OF HOURS...MAINLY TO THE NORTH NEAR FORT COLLINS AND GREELEY. NOT CONVINCED THIS WILL HAPPEN BUT DO NOT WANT TO LESSEN THE POPS ANY FURTHER TIL I KNOW FOR SURE. IF A STRONG ENOUGH OUTFLOW COULD SLIPS INTO DENVER FROM THE NORTH...IT COULD STILL TRIGGER SOME ADDITIONAL DEVELOPMENT. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 341 PM MDT FRI MAY 1 2015 THUNDERSTORMS ARE PRESENTLY MOVING OVER THE PALMER DIVIDE AND OFF THE FOOTHILLS OF BOULDER AND JEFFERSON COUNTY. SOUTHEASTERLY LOW LEVEL WINDS AND SURFACE DEW POINTS IN THE MID AND UPPER 40S SHOULD BE SUFFICIENT TO KEEP THUNDERSTORMS DEVELOPING ACROSS THE PLAINS EARLY THIS EVENING. HAIL UP TO THREE-QUARTERS OF AN INCH WILL BE THE MOST COMMON THREAT FROM THE PULSE-TYPE CONVECTION. WIND SHEAR ALOFT DOES NOT SEEM TO BE STRONG ENOUGH FOR ORGANIZED SUPERCELLS TO DEVELOP. RAINFALL AMOUNTS FROM ALERT GAGES HAVE SHOWN RAINFALL AMOUNTS STAYING LESS THAN A HALF INCH. SOME AREAS MAY RECEIVE SOME STANDING WATER IMMEDIATELY AFTER STORM PASSAGE...BUT NO OTHER PROBLEMS ARE EXPECTED. SKIES SHOULD BECOME PARTLY CLOUDY TO MOSTLY CLEAR LATER TONIGHT AFTER THE EVENING CONVECTION DIES DOWN. SOUTHERLY WINDS ARE EXPECTED TO PREVAIL AS HIGH PRESSURE BUILDS OVER THE CENTRAL PLAINS. TOMORROW SHOULD BE A REPEAT OF TODAY AS THE FLAT UPPER RIDGE REMAINS OVER COLORADO AND MOISTURE REMAINS OVER THE STATE. DAYTIME HEATING WILL AGAIN BE SUFFICIENT TO DE-STABILIZE THE AIRMASS. ONCE AGAIN THE WIND STRUCTURE WILL BE WEAK...SO ONLY SCATTERED NON-SEVERE THUNDERSTORMS ARE EXPECTED. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 341 PM MDT FRI MAY 1 2015 MODELS HAVE WEAK SOUTHWESTERLY FLOW ALOFT FOR THE CWA SATURDAY NIGHT THROUGH MONDAY WITH A WEAK UPPER CLOSED LOW TO MOVE INTO THE FOUR CORNERS BY 12Z TUESDAY MORNING. THE QG FIELDS HAVE WEAK UPWARD VERTICAL VELOCITY PROGGED FOR ALL THE CWA SATURDAY NIGHT THROUGH MONDAY NIGHT. THE BOUNDARY LAYER WINDS WILL BE PRETTY WEAK WITH NORMAL DIURNAL PATTERNS SATURDAY NIGHT. THEN A WEAK COLD FRONT WITH UPSLOPE NORTHEASTERLIES ARE PROGGED SUNDAY...WITH EAST-SOUTHEASTERLIES SUNDAY NIGHT THROUGH MONDAY NIGHT. MOISTURE- WISE...SATURDAY EVENING IS FAIRLY DRY. THIS CARRIES INTO SUNDAY MORNING...WITH A SIGNIFICANT INCREASE IN MOISTURE SUNDAY AFTERNOON. BY SUNDAY NIGHT...THE NAM AND ECMWF FURTHER INCREASE MOISTURE...CONTINUING INTO MONDAY. THE GFS DOES NOT DO THIS UNTIL MONDAY AFTERNOON. BOTH THE GFS AND ECMWF SHOW A VERY MOIST MONDAY NIGHT. THE QPF FIELDS HAVE A TAD OF MEASURABLE PRECIPITATION PROGGED SATURDAY EVENING. BY SUNDAY AFTERNOON...THERE IS MUCH MORE PROGGED. THERE IS QPF NOTED ALL SUNDAY NIGHT...MONDAY MORNING... THROUGH MONDAY EVENING...THEN LESS MONDAY OVERNIGHT. THE DEW POINTS ARE IN THE 30S AND LOWER 40S F SATURDAY NIGHT INTO SUNDAY...THEN THEY INCREASE INTO THE 40S TO LOWER 50S FROM LATER SUNDAY THROUGH MONDAY NIGHT. THERE IS SOME CAPE BOTH SATURDAY EVENING...THEN LATE DAY SUNDAY AS WELL...BUT VALUES ARE NOT ABOVE 1000 J/KG EITHER DAY. THERE IS LESS CAPE AROUND FOR LATE DAY MONDAY WITH NONE OVER THE EASTERN HALF OF THE PLAINS. FOR POPS...MINOR ONES SATURDAY EVENING...NOTHING OVERNIGHT...THEN MINOR AGAIN IN THE MOUNTAINS SUNDAY MORNING. BY SUNDAY AFTERNOON THROUGH MONDAY NIGHT WILL GO WITH 30-50%S. FOR TEMPERATURES...SUNDAY`S HIGHS ARE 3-5 C COOLER THAN SATURDAY`S. MONDAY`S HIGHS ARE 1-5 C COOLER AGAIN FROM SUNDAY`S. FOR THE LATER DAYS...TUESDAY THROUGH FRIDAY...MODELS CONTINUE TO SHOW UPPER TROUGHINESS FOR THE CWA ALL FOUR DAYS. THERE IS GOOD MOISTURE MUCH OF THE TIME WITH THE EXCEPTION OF FRIDAY. IT WILL BE A WET...UNSETTLED PERIOD WITH TEMPERATURES A BIT BELOW NORMALS. && .AVIATION...(FOR THE TAFS THROUGH 06Z SATURDAY EVENING) ISSUED AT 945 PM MDT FRI MAY 1 2015 VFR CONDITIONS THROUGH MID AFTERNOON SATURDAY WITH DRAINAGE WINDS OVERNIGHT. COULD SEE ILS CIGS DEVELOPS WITH ANY DEVELOPING TSTMS AFTER 21Z SATURDAY. COVERAGE APPEARS ISOLATED WITH BETTER COVERAGE NORTH OF DENVER IF A WEAK DISTURBANCE MAKES ITS WAY ALONG THE NORTHERN BORDER IN THE AFTERNOON. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KRIEDERMAN SHORT TERM...DANKERS LONG TERM...RJK AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1130 PM MDT FRI MAY 1 2015 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 257 PM MDT FRI MAY 1 2015 ...STORMS MOVING INTO EASTERN COLORADO THIS EVENING... ...WARM WEEKEND ON THE WAY... LATEST HRRR HAS A DECENT HANDLE ON THE CONVECTION...AND ALONG WITH OTHER HI-RES GUIDANCE SHOWS A WAVE OF CONVECTION INCREASING IN COVERAGE OVER THE I-25 CORRIDOR THIS AFTERNOON...THEN CLEARING I-25 BY 00-01Z THIS EVENING. STORMS WILL THEN CONSOLIDATE INTO AN MCS OVER THE ERN PLAINS THIS EVENING. THEN...SHOULD SEE SHOWERS AND STORMS MOVING INTO WRN KS BY 03Z OR SO THIS EVE. AFTER 06Z...PRECIP SHOULD BE OVER FOR MOST OF THE AREA...WITH JUST SOME LINGERING SHOWERS POSSIBLE OVER THE FAR ERN PLAINS AND HYR TRRN. UPPER RIDGE AND ASSOCIATED AVA SHOULD HELP SUPPRESS THINGS THROUGH SAT MORNING. TOMORROW...A WARMER DAY IS IN STORE...AS FLOW BECOMES A BIT MORE ZONAL AND H7 TEMPS RISE TO AROUND 10 DEG C. EXPECT 80 PLUS DEG TEMPS OVER MUCH OF THE PLAINS BY AFTERNOON...WITH 60S AND 70S FOR THE HIGHER ELEVATIONS. ANOTHER WEAK DISTURBANCE WILL SPARK SOME AFTERNOON STORMS MOVING OFF THE MTS SAT AFTERNOON...BUT WITH DEW POINTS IN THE 30S CONVECTION WILL NOT BE AS STRONG AS IT IS/WILL BE TODAY...AND COVERAGE A BIT LESS AS WELL. ROSE .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 257 PM MDT FRI MAY 1 2015 A RATHER WET PERIOD IS EXPECTED THE FIRST PART HALF OF NEXT WEEK. ON SUN AN UPR TROF WL MOVE TO ALONG THE CA COAST...WITH MSTR AHEAD OF THIS SYSTEM MOVING INTO THE FORECAST AREA...ALONG WITH A SHORTWAVE TROF IN THE AFTERNOON AND EVENING HOURS. IT STILL LOOKS LIKE A FRONT WL HANG UP ALONG THE PALMER DVD SUN AFTERNOON AND THEN WORK ITS WAY SOUTH IN THE EVENING HOURS. MUCH OF THE AREA WL SEE AT LEAST ISOLD TO SCT SHOWERS AND TSTMS SUN AND SUN EVENING. HIGH TEMPS ON SUN SHOULD STILL BE ABOVE AVERAGE BY ABOUT 5-10 DEG. ON MON THE UPR TROF MOVES INTO THE WRN STATES...WITH AN UPR LOW CENTER EXPECTED TO BE OVR SWRN AZ BY 00Z TUE. MSTR WL CONTINUE STREAMING INTO THE FORECAST AREA AHEAD OF THIS SYSTEM. OVR ERN PORTIONS OF THE FORECAST AREA...LOW TO MID LEVEL SERLY WINDS SHOULD HELP ENHANCE PCPN CHANCE ALONG AND ADJACENT TO THE ERN MTNS. WIDESPREAD PCPN IS EXPECTED ON MON ALONG WITH COOLER TEMPS. THE ECMWF AND GFS LIFT THE UPR LOW NORTHEASTWARD ON TUE. THE GFS IS A LITTLE FARTHER NORTH THAN THE GFS WITH THE LOW CENTER. THE GFS HAS IT IN NERN CO BY 00Z WED WITH THE ECMWF SHOWING IT OVR SERN CO. EITHER WAY...WIDESPREAD PCPN SHOULD CONTINUE THRU TUE. THIS SYSTEM WEAKENS AS IT MOVES NORTH-NORTHEASTWARD TUE NIGHT THROUGH WED...MOVING INTO THE WRN DAKOTAS BY 00Z THU. ALTHOUGH PCPN CHANCES ARE EXPECTED TO DECREASE SOME TUE NIGHT...THERE SHOULD STILL BE PLENTY OF MSTR AROUND FOR AN INCREASE IN ACTIVITY IN THE AFTERNOON AND EVENING HOURS ON WED AS THINGS REMAIN UNSETTLED. TEMPS REMAIN QUITE WARM AS THIS SYSTEM AFFECTS THE AREA AND SNOW ACCUMULATIONS ARE GENERALLY EXPECTED TO REMAIN OVR THE HYR MTN AREAS. SOME AREAS...ESPECIALLY NR THE ERN MTN...COULD SEE PERIODS OF HEAVY RAIN. ANOTHER UPR LOW IS THEN FORECAST TO MOVE INTO THE GREAT BASIN FOR LATE THU AND FRI. THIS WL KEEP THE WX UNSETTLED WITH PROBABLY FAIRLY WIDESPREAD PCPN CHANCES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1130 PM MDT FRI MAY 1 2015 OUTSIDE OF ISOLATED PRIMARILY AFTERNOON SHOWERS AND THUNDERSTORMS...TAF SITES KALS...KCOS AND KPUB SHOULD EXPERIENCE VFR CONDITIONS INTO FRIDAY EVENING. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
348 PM EDT SAT MAY 2 2015 .SYNOPSIS... HIGH PRESSURE WILL REMAIN TO OUR SOUTH THROUGH MONDAY, KEEPING FAIR WEATHER ACROSS THE AREA. A COLD FRONT IS FORECAST TO MOVE ACROSS THE AREA TUESDAY, THEN STALL SOUTH OF THE AREA THROUGH THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... A COMBINATION OF THE GFS AND WRF-NMM LOOKED BEST OFF THE 500MB INITIALIZATION WITH A SLIGHT NOD TO THE WRF-NMMB AT BOTH 850MB AND 925MB WHERE THE GFS SHOWED SOME 1C COLD BIASES. MODERATING TREND THROUGH THE SHORT TERM WILL CONTINUE WITH LITTLE IF ANY PCPN AND NO PCPN EXPECTED AFTER EARLY THIS EVENING. THE HRRR HAD A GOOD HANDLE ON LOCATIONS OF BULKIER CU AND ADJUSTMENTS TO ISOLATED SHOWERS (MORE LIKELY JUST SPRINKLES OR A FEW BIG DROPS HITTING THE WINDSHIELD) WERE BASED ON ITS LATEST OUTPUT. FORECAST SOUNDINGS STILL ARE CAPPED AND WITH THE SHORT WAVE MOVING OFFSHORE SHOULD ONLY BECOME MORE SO AS THE AFTN AND EARLY EVE PROGRESS, SO NO THUNDER. BASED ON UPWIND SATL INFO, DOESNT LOOK LIKE CLOUDS ARE GOING TO GET TRAPPED UNDER THE INVERSION, SO MOST SHOULD BE GONE BY EVENING`S END. WINDS WILL BE LIGHT, IF NOT CALM, IN MOST AREAS. WE RADIATED MIN TEMPS DOWN TOWARD THE LOWER STAT GUIDANCE DATASETS. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... INCREASED RIDGING AND FARTHER OFFSHORE MOVEMENT OF THE 500MB TROF AND SFC LOW WILL TRANSLATE INTO A WARMER DAY ON SUNDAY WITH LESS CUMULUS CLOUDS AROUND AND NO CHANCE FOR PCPN. 18C AIR AT BOTH 925MB AND 850MB OVER THE UPPER PLAINS WILL START MAKING A TURN TOWARD OUR CWA, BUT NOT ARRIVE IN TIME FOR SUNDAY. NEVERTHELESS, THERE WILL BE A SEVERAL DEG C UPTICK IN TEMPS AT BOTH THOSE LEVELS SUNDAY. LIKE TODAY, THE WARMER PART OF OUR AIR MASS WILL BE OVER THE NWRN PART OF OUR CWA VS SOUTHEAST. THUS MAX TEMPS (AWAY FROM THE IMMEDIATE SHORE AND HIGHER TERRAIN) ARE PREDICTED TO BE QUITE UNIFORM. THIS IS IN LINE WITH FCST CONTINUITY AND THE HIGHER MOS DATASETS. A SEA BREEZE FRONT SHOULD FORM AGAIN, LIKELY NOT AS VIGOROUS AS TODAY`S. NONETHELESS SOME COOLING WILL OCCUR AT OR CLOSER TO THE COAST AS THE AFTERNOON PROGRESSES. WATER TEMPS ARE STILL QUITE CHILLY. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... THE HIGH PRESSURE TO OUR SOUTH BUILDS SLIGHTLY FURTHER OFFSHORE SUNDAY NIGHT, BUT MOSTLY REMAINS IN PLACE THROUGH MONDAY. THE HIGH WILL BEGIN GETTING SQUEEZED FURTHER OFFSHORE AND AWAY FROM THE AREA MONDAY NIGHT. HOWEVER, OUR AREA ON THE NORTHERN FRINGE OF THE HIGH THROUGH MONDAY NIGHT, WHICH WILL KEEP RATHER TRANQUIL WEATHER ACROSS THE AREA THROUGH MONDAY NIGHT. A COLD FRONT IS FORECAST TO MOVE ACROSS THE AREA TUESDAY INTO TUESDAY NIGHT, WHILE PW VALUES INCREASE TO AROUND 1.0-1.5 INCHES. WITH AN INCREASE IN MOISTURE AND WARM TEMPERATURES, THERE IS SOME INSTABILITY FORECAST, WITH MLCAPE VALUES AROUND 500 J/KG, SLIGHTLY NEGATIVE LI VALUES, AND TOTAL TOTAL VALUES NEAR 50. SO AS THE FRONT MOVES THROUGH THE AREA, SCATTERED SHOWERS ARE EXPECTED, ALONG WITH ISOLATED THUNDERSTORMS. THE FRONT SHOULD MOVE ACROSS THE AREA INTO TUESDAY NIGHT, AND SHOWER/THUNDERSTORM ACTIVITY SHOULD MOVE THROUGH WITH THE FRONT AND/OR DIMINISH THROUGH THE NIGHT. AS THE FRONT SLOWLY PASSES THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY, IT IS FORECAST TO STALL OUT TO OUR SOUTH THROUGH THE REMAINDER OF THE WEEK, AND MAY END UP WASHING OUT TO OUR SOUTH. WITH THE FRONT TO OUR SOUTH, HIGH PRESSURE FROM THE NORTH WILL TRY TO NOSE ITS WAY INTO THE AREA THROUGH THE END OF THE WEEK. THIS SHOULD KEEP THE WEATHER DRY THROUGH FRIDAY, AND WITH RIDGING BUILDING ALOFT, TEMPERATURES ARE FORECAST TO REMAIN ABOVE NORMAL THROUGH THE END OF THE WEEK. WEDNESDAY MAY BE THE COOLEST DAY WITH A NORTH/NORTHEAST FLOW ACROSS THE AREA WHICH MAY BRING IN COOLER AIR AND KEEP CLOUD COVER IN AS WELL. THE DRY WEATHER SHOULD REMAIN THROUGH FRIDAY NIGHT, BUT ISOLATED SHOWERS MAY RETURN FOR SATURDAY AS RETURN FLOW DEVELOPS ACROSS THE AREA, INCREASING MOISTURE AND DAYTIME INSTABILITY ACROSS THE AREA WHICH COULD LEAD TO A SLIGHT CHANCE OF SHOWERS, ESPECIALLY ACROSS THE WESTERN HALF OF THE AREA. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. 18Z TAFS WERE VFR. REST OF THIS AFTERNOON...CU BASED VFR CIG FROM THE DELAWARE RIVER VALLEY TERMINALS NORTHWESTWARD. WE EXPECT KACY AND KMIV TO PREVAIL WITHOUT A CIG. SOME ISOLATED SHOWERS ARE POSSIBLE NORTHERN AIRPORTS, EVEN MORE ISOLATED THAN YESTERDAY AND WERE NOT INCLUDED. SEA BREEZE FRONT IS MAKING CONSIDERABLE WESTWARD MOVEMENT. AT 20Z IT WAS FROM ABOUT KMIV TO CHATSWORTH IN BURLINGTON COUNTY THRU MOST OF OCEAN COUNTY AND ALONG THE MIDDLESEX AND MONMOUTH COUNTY LINE. PRECEDING IT WINDS ARE LIGHT FROM A WESTERLY COMPONENT AT LESS THAN 10 KNOTS. BY 21Z SEA/BAY BREEZE FRONT SHOULD SHOULD BE THROUGH ALL OF DELAWARE BAY TO KVAY AND KSMQ. BY 23Z MORE CONFIDENT IT SHOULD BE THROUGH DELAWARE AND THE DELAWARE RIVER AIRPORTS INCLUDING KPHL AND BE APPROACHING KLOM AND KDYL. WINDS BEHIND THE SEA BREEZE FRONT SHOULD BE SOUTH TO SOUTHEAST AT AROUND 10 KNOTS. THIS EVENING...THE SEA BREEZE FRONT ADVANCEMENT SHOULD SLOW. IT MIGHT MAKE IT TO KABE. OTHERWISE WINDS WILL BE LIGHT AND VARIABLE WITH SOME VFR ISOLATED/SCATTERED MID LEVEL DEBRIS CLOUDS. OVERNIGHT...CLEAR SKIES AND LIGHT AND VARIABLE WINDS. WE DO NOT HAVE FOG PREDICTED AT THE TERMINALS. CONFIDENCE ABOUT NO FOG AT MORE RURAL AIRPORTS IS MODERATE. AIR MASS HAS BEEN CLEAN AND DEW POINTS ARE NOT RISING THIS AFTERNOON. SUNDAY MORNING INTO EARLY AFTERNOON...VFR NO CIG EXPECTED, LESS CUMULUS CLOUDS THAN TODAY. WINDS BECOMING WEST AT 5 TO 10 KNOTS. ANOTHER SEA BREEZE FRONT IS EXPECTED TO DEVELOP AND WE START THAT AT KACY AT 17Z. OUTLOOK... SUNDAY NIGHT-MONDAY NIGHT...VFR. SOUTHWEST WIND GUSTS AROUND 20 KNOTS MONDAY. TUESDAY-TUESDAY NIGHT...GENERALLY VFR WITH SHOWERS POSSIBLE. SOUTHWEST WIND GUSTS AROUND 20 KNOTS TUESDAY. WEDNESDAY...MOSTLY VFR, POSSIBLE NEAR MVFR CIGS. WEDNESDAY NIGHT-THURSDAY...IMPROVING CONDITIONS TO VFR OVERNIGHT AND CONTINUING THROUGH THURSDAY. && .MARINE... SEAS CONTINUE TO BE SLOWER TO SUBSIDE THAN ANTICIPATED AS THE OFFSHORE PROGRESSION OF THE LOW IS NOT FAST ENOUGH TO NEGATE THE WESTWARD PROPAGATION OF HIGHER SEAS. WAVE WATCH GUIDANCE CONTINUES TO RUN APPROXIMATELY HALF A FOOT TOO LOW. BUOY65 SEAS HAVE BEEN HOLDING AT 4 FEET, SO WE WILL HOLD OFF ON REISSUING A SCA FOR THE MONMOUTH COASTAL WATERS. THE OTHER COASTAL WATERS, WE WILL EXTEND THE SCA FOR SEVERAL MORE HOURS INTO THE NIGHT. ON DELAWARE BAY, IN THE NEAR TERM A STRONG BAY BREEZE WILL WORK ITS WAY UP THE BAY, BUT GUSTS SHOULD BE JUST BELOW SCA CRITERIA. WINDS WILL DECREASE THIS EVENING. WE REMAIN CONFIDENT THAT SUB SMALL CRAFT ADVISORY CONDITIONS WILL OCCUR ON SUNDAY AS THE LOW MOVES FARTHER OFFSHORE AND A HIGH PRESSURE RIDGES OVER THE COASTAL WATERS. A SEA BREEZE FLOW SHOULD DEVELOP AGAIN AND CHANNEL UP DELAWARE BAY. OUTLOOK... SUNDAY NIGHT-THURSDAY...SUB SMALL CRAFT ADVISORY CONDITIONS EXPECTED. HOWEVER, WINDS MAY GUST AROUND 20 KNOTS AND SEAS APPROACH 4 FEET THROUGH THE PERIOD. FRONTAL BOUNDARY IS EXPECTED TO MOVE SOUTH OF THE WATERS ON TUESDAY AND STALL TO OUR SOUTH THROUGH THE END OF THE WEEK. && .FIRE WEATHER... RELATIVE HUMIDITY VALUES AROUND 25-30 PERCENT, ALONG WITH WIND GUSTS OF 20-25 MPH WILL LEAD TO ENHANCED FIRE WEATHER CONCERNS ON MONDAY FOR PORTIONS OF THE FORECAST AREA. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EDT SUNDAY FOR ANZ452>455. SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ451. && $$ SYNOPSIS...ROBERTSON NEAR TERM...GIGI SHORT TERM...GIGI LONG TERM...ROBERTSON AVIATION...GIGI/ROBERTSON MARINE...GIGI/ROBERTSON FIRE WEATHER...ROBERTSON
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
102 PM EDT SAT MAY 2 2015 .SYNOPSIS... LOW PRESSURE OFF THE NORTH CAROLINA COAST WILL MOVE FARTHER OUT TO SEA THIS AFTERNOON. AN EXPANSIVE AREA OF HIGH PRESSURE WILL REMAIN IN CONTROL OF THE EASTERN THIRD OF THE COUNTRY THIS WEEKEND. THE CENTER OF THE HIGH WILL SHIFT OFFSHORE SUNDAY NIGHT AND MONDAY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY NIGHT. THIS FRONT IS EXPECTED TO WEAKEN AND STALL OVER THE AREA TUESDAY INTO WEDNESDAY. HIGH PRESSURE BUILDS BACK INTO THE AREA LATE IN THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CURRENT ESTF WE ADJUSTED MAX TEMPS UPWARD INLAND A COUPLE OF DEGREES BASED ON CURRENT OBS AND TRENDS. WE DIDNT CHANGE LOW POPS MUCH AS INLAND CU ARE SHOWING SOME VERTICAL DEVELOPMENT. SOUNDINGS LOOK CAPPED, SO THUNDER NOT EXPECTED EVENT THOUGH WE DO HAVE SOME CAPE AND SFC BASED LI(S) SHOULD BE DROPPING TO AROUND 0C. HIGH PRESSURE WILL SLOWLY BUILD INTO THE REGION FROM THE W AS LOW PRES OFF THE COAST MOVES AWAY FROM THE REGION. AS A RESULT, MAINLY DRY WX AND WARMING TEMPS ARE IN STORE TODAY. WITH LIGHT FLOW, TEMPS WILL BE COOLER ALG THE CST WHERE A SEABREEZE IS EXPECTED TO DEVELOP AND MOVE PRETTY FAR INLAND AS THE AFTERNOON PROGRESSES. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/... THE SFC RIDGE WILL MOVE FURTHER INTO THE REGION TONIGHT AND EXPECT A GENLY CLEAR SKY AND NOT MUCH WIND. && .LONG TERM /SUNDAY THROUGH FRIDAY/... THE LARGE-SCALE PLAYERS NEXT WEEK INCLUDE PERSISTENT TROUGHING OVER THE WESTERN CONUS AND DOWNSTREAM RIDGING OVER MUCH OF THE EASTERN CONUS AND WESTERN ATLANTIC. THIS PATTERN WILL RESULT IN WARMER THAN NORMAL TEMPS AND FEW OPPORTUNITIES FOR PRECIPITATION FOR THE MID-ATLANTIC REGION FOR THE LONG-TERM PERIOD. MAX TEMPS GENERALLY RANGE FROM THE MID 70S TO LOWER 80S EACH DAY (EXCEPT COOLER ALONG THE COAST AND IN THE POCONOS). THE CENTER OF THE SURFACE HIGH PRESSURE AND H8 ANTICYCLONE WILL BE POSITIONED OVER THE SOUTHEAST STATES ON SUNDAY. THESE FEATURES WILL PROGRESS DOWNSTREAM TOWARD THE EAST COAST SUNDAY NIGHT AND THEN OVER THE WESTERN ATLANTIC ON MONDAY. SOUTHWESTERLY RETURN FLOW AROUND THE HIGH WILL DRAW EVEN WARMER AND SLIGHTLY MORE HUMID AIR UP THE EASTERN SEABOARD. A COLD FRONT IS EXPECTED TO DROP SOUTHWARD INTO THE REGION TUESDAY MORNING. THE COMBINATION OF UNIDIRECTIONAL W-SW FLOW ALOFT THAT BECOMES ORIENTED PARALLEL TO THE BOUNDARY AND DOWNSTREAM BLOCKING (FROM THE HIGH OVER THE WESTERN ATLANTIC AND CAROLINAS) WILL LIKELY CAUSE THE FRONT TO STALL OVER THE FORECAST AREA THRU WEDNESDAY. THE BOUNDARY WILL ALSO BECOME INCREASINGLY DIFFUSE DURING THIS TIME. THE BEST, IF NOT THE ONLY APPRECIABLE CHANCE FOR PRECIPITATION NEXT WEEK WILL BE TUESDAY-WEDNESDAY. WHILE FORCING FROM THIS DECAYING BOUNDARY ITSELF WILL BE WEAK, WE WILL HAVE TO WATCH FOR MID-LEVEL SHORTWAVE ENERGY THAT EJECTS OUT OF THE SOUTHWEST CONUS TROUGH TO RIDE ATOP THE DOWNSTREAM RIDGE AND EVENTUALLY MOVE INTO OUR AREA SOMETIME DURING THE TUESDAY AFTERNOON- WEDNESDAY MORNING PERIOD. THIS WOULD ENHANCE COVERAGE OF SHOWERS. HOWEVER, THE TIMING AND STRENGTH OF ANY SUCH IMPULSE IS STILL UNCERTAIN THIS FAR OUT, SO POPS WERE KEPT GENERALLY LOW. THE 00Z GUIDANCE PROGS THE GREATER INSTABILITY THAT MAY BE SUFFICIENT FOR CONVECTION TO BE CONFINED TO NEAR THE FRONT OWING TO MOISTURE POOLING ALONG THE BOUNDARY. KEPT CHANCES FOR THUNDERSTORMS LOW AREA WIDE DUE TO UNCERTAINTY IN THE LOCATION OF THE BOUNDARY. THE REMNANTS OF THE OLD FRONTAL BOUNDARY IS FORECAST TO BECOME WASHED OUT ACROSS THE AREA BY WEDNESDAY NIGHT. UPPER RIDGE BUILDING WILL OCCUR OVER THE MIDWEST AND MID ATLANTIC LATE IN THE WEEK. THIS ALLOWS THE WARMTH TO PERSIST ACROSS THE FORECAST AREA THRU THE END OF THE WEEK. MODELS ARE IN GOOD AGREEMENT WITH A CUTOFF LOW FORMING OFF THE SOUTHEAST COAST THURSDAY. WITH WEAK STEERING FLOW UNDERNEATH THE UPPER RIDGE, THE LOW IS NOT EXPECTED TO MAKE MUCH ADVANCEMENT TOWARD OUR AREA, RESULTING IN A DRY FORECAST FOR THURSDAY AND FRIDAY. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. 18Z TAFS ARE VFR. THIS AFTERNOON...CU BASED VFR CIG IS DEVELOPING NORTHWEST HALF OF OUR AREA AND THIS SHOULD CONTINUE. SOME ISOLATED SHOWERS ARE POSSIBLE NORTHWEST AIRPORTS, EVEN MORE ISOLATED THAN YESTERDAY AND WERE NOT INCLUDED. BIGGEST FEATURE WILL BE A SEA BREEZE FRONT THAT IS EXPECTED TO MAKE CONSIDERABLE WESTWARD MOVEMENT. PRECEDING IT WINDS SHOULD BE LIGHT FROM THE WEST TO NORTHWEST AT LESS THAN 10 KNOTS. THE SEA BREEZE FRONT IS ALREADY JUST INLAND IN MONMOUTH AND OCEAN COUNTIES AND BY 21Z SHOULD REACH KMIV-KVAY AND APPROACHING KSMQ. BY 23Z IT SHOULD BE THROUGH MOST OF DELAWARE AND THE DELAWARE RIVER AIRPORTS INCLUDING KPHL AND BE APPROACHING KLOM AND KDYL. WINDS BEHIND THE SEA BREEZE FRONT SHOULD BE SOUTH TO SOUTHEAST AT AROUND 10 KNOTS. THIS EVENING...THE SEA BREEZE FRONT ADVANCEMENT SHOULD SLOW. IT MIGHT MAKE IT TO KABE. OTHERWISE WINDS WILL BE LIGHT AND VARIABLE WITH SOME VFR ISOLATED/SCATTERED MID LEVEL DEBRIS CLOUDS. OVERNIGHT...CLEAR SKIES AND LIGHT AND VARIABLE WINDS. WE DO NOT HAVE FOG PREDICTED AT THE TERMINALS. CONFIDENCE ABOUT NO FOG AT MORE RURAL AIRPORTS IS MODERATE. AIR MASS HAS BEEN CLEAN AND DEW POINTS ARE NOT RISING THIS AFTERNOON. SUNDAY MORNING INTO EARLY AFTERNOON...VFR NO CIG EXPECTED, LESS CUMULUS CLOUDS THAN TODAY. WINDS BECOMING WEST AT 5 TO 10 KNOTS. ANOTHER SEA BREEZE FRONT IS EXPECTED TO DEVELOP AND WE START THAT AT KACY AT 17Z. OUTLOOK... SUNDAY AFTERNOON AND MONDAY...VFR. LIGHT NW WINDS SUNDAY WILL BECOME SWLY AND INCREASE ON MONDAY. GUSTS TO 20 KT POSSIBLE MONDAY AFTERNOON. TUESDAY AND WEDNESDAY...PREDOMINATELY VFR. BRIEF/LOCAL RESTRICTIONS IN SCT SHOWERS AND ISO TSTMS AS A COLD FRONT DROPS SOUTHWARD AND THEN STALLS OVER THE AREA. BEST CHANCE FOR PRECIP WOULD BE TUESDAY AFTERNOON THRU WEDNESDAY MORNING. && .MARINE... WE MADE A COUPLE OF CHANGES TO THE WINDS FOR THIS AFTERNOON AND EVENING BASED ON LATEST 12Z NAM AND SOME OF THE LATEST HRRR AND RAP AS THEY HAVE A DECENT WIND SHIFT/ SEA AND BAY BREEZE FRONT PREDICTED TO DEVELOP. WE WILL EXTEND THE SCA FOR A FEW MORE HOURS AS OBSERVED SEAS ARE ABOUT A FOOT ABOVE WAVE WATCH GUIDANCE. ONCE THIS CURRENT SCA COMES DOWN, NO ADDITIONAL MARINE HEADLINES ARE EXPECTED IN THE NR OR SHORT TERM PDS. OUTLOOK... SUNDAY THROUGH WEDNESDAY...WINDS AND WAVES WILL PREDOMINATELY STAY BELOW SCA CRITERIA. S-SW FLOW WILL INCREASE TO 15-20 KT MONDAY AFTERNOON THRU WEDNESDAY BUT THE WARM AIR ATOP THE COLDER WATERS WILL NOT PROVIDE MUCH OPPORTUNITY FOR STRONGER WINDS ALOFT TO MIX DOWN TO THE SURFACE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ452>455. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ451. && $$ SYNOPSIS...KLEIN NEAR TERM...GIGI/NIERENBERG SHORT TERM...NIERENBERG LONG TERM...KLEIN AVIATION...GIGI/KLEIN MARINE...GIGI/KLEIN/NIERENBERG
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1232 PM EDT SAT MAY 2 2015 .SYNOPSIS... LOW PRESSURE OFF THE NORTH CAROLINA COAST WILL MOVE FARTHER OUT TO SEA TODAY. AN EXPANSIVE AREA OF HIGH PRESSURE WILL REMAIN IN CONTROL OF THE EASTERN THIRD OF THE COUNTRY THIS WEEKEND. THE CENTER OF THE HIGH WILL SHIFT OFFSHORE SUNDAY NIGHT AND MONDAY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY NIGHT. THIS FRONT IS EXPECTED TO WEAKEN AND STALL OVER THE AREA TUESDAY INTO WEDNESDAY. HIGH PRESSURE BUILDS BACK INTO THE AREA LATE IN THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CURRENT ESTF WE ADJUSTED MAX TEMPS UPWARD INLAND A COUPLE OF DEGREES BASED ON CURRENT OBS AND TRENDS. WE DIDNT CHANGE LOW POPS MUCH AS INLAND CU ARE SHOWING SOME VERTICAL DEVELOPMENT. SOUNDINGS LOOK CAPPED, SO THUNDER NOT EXPECTED EVENT THOUGH WE DO HAVE SOME CAPE AND SFC BASED LI(S) SHOULD BE DROPPING TO AROUND 0C. HIGH PRESSURE WILL SLOWLY BUILD INTO THE REGION FROM THE W AS LOW PRES OFF THE COAST MOVES AWAY FROM THE REGION. AS A RESULT, MAINLY DRY WX AND WARMING TEMPS ARE IN STORE TODAY. WITH LIGHT FLOW, TEMPS WILL BE COOLER ALG THE CST WHERE A SEABREEZE IS EXPECTED TO DEVELOP AND MOVE PRETTY FAR INLAND AS THE AFTERNOON PROGRESSES. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/... THE SFC RIDGE WILL MOVE FURTHER INTO THE REGION TONIGHT AND EXPECT A GENLY CLEAR SKY AND NOT MUCH WIND. && .LONG TERM /SUNDAY THROUGH FRIDAY/... THE LARGE-SCALE PLAYERS NEXT WEEK INCLUDE PERSISTENT TROUGHING OVER THE WESTERN CONUS AND DOWNSTREAM RIDGING OVER MUCH OF THE EASTERN CONUS AND WESTERN ATLANTIC. THIS PATTERN WILL RESULT IN WARMER THAN NORMAL TEMPS AND FEW OPPORTUNITIES FOR PRECIPITATION FOR THE MID-ATLANTIC REGION FOR THE LONG-TERM PERIOD. MAX TEMPS GENERALLY RANGE FROM THE MID 70S TO LOWER 80S EACH DAY (EXCEPT COOLER ALONG THE COAST AND IN THE POCONOS). THE CENTER OF THE SURFACE HIGH PRESSURE AND H8 ANTICYCLONE WILL BE POSITIONED OVER THE SOUTHEAST STATES ON SUNDAY. THESE FEATURES WILL PROGRESS DOWNSTREAM TOWARD THE EAST COAST SUNDAY NIGHT AND THEN OVER THE WESTERN ATLANTIC ON MONDAY. SOUTHWESTERLY RETURN FLOW AROUND THE HIGH WILL DRAW EVEN WARMER AND SLIGHTLY MORE HUMID AIR UP THE EASTERN SEABOARD. A COLD FRONT IS EXPECTED TO DROP SOUTHWARD INTO THE REGION TUESDAY MORNING. THE COMBINATION OF UNIDIRECTIONAL W-SW FLOW ALOFT THAT BECOMES ORIENTED PARALLEL TO THE BOUNDARY AND DOWNSTREAM BLOCKING (FROM THE HIGH OVER THE WESTERN ATLANTIC AND CAROLINAS) WILL LIKELY CAUSE THE FRONT TO STALL OVER THE FORECAST AREA THRU WEDNESDAY. THE BOUNDARY WILL ALSO BECOME INCREASINGLY DIFFUSE DURING THIS TIME. THE BEST, IF NOT THE ONLY APPRECIABLE CHANCE FOR PRECIPITATION NEXT WEEK WILL BE TUESDAY-WEDNESDAY. WHILE FORCING FROM THIS DECAYING BOUNDARY ITSELF WILL BE WEAK, WE WILL HAVE TO WATCH FOR MID-LEVEL SHORTWAVE ENERGY THAT EJECTS OUT OF THE SOUTHWEST CONUS TROUGH TO RIDE ATOP THE DOWNSTREAM RIDGE AND EVENTUALLY MOVE INTO OUR AREA SOMETIME DURING THE TUESDAY AFTERNOON- WEDNESDAY MORNING PERIOD. THIS WOULD ENHANCE COVERAGE OF SHOWERS. HOWEVER, THE TIMING AND STRENGTH OF ANY SUCH IMPULSE IS STILL UNCERTAIN THIS FAR OUT, SO POPS WERE KEPT GENERALLY LOW. THE 00Z GUIDANCE PROGS THE GREATER INSTABILITY THAT MAY BE SUFFICIENT FOR CONVECTION TO BE CONFINED TO NEAR THE FRONT OWING TO MOISTURE POOLING ALONG THE BOUNDARY. KEPT CHANCES FOR THUNDERSTORMS LOW AREA WIDE DUE TO UNCERTAINTY IN THE LOCATION OF THE BOUNDARY. THE REMNANTS OF THE OLD FRONTAL BOUNDARY IS FORECAST TO BECOME WASHED OUT ACROSS THE AREA BY WEDNESDAY NIGHT. UPPER RIDGE BUILDING WILL OCCUR OVER THE MIDWEST AND MID ATLANTIC LATE IN THE WEEK. THIS ALLOWS THE WARMTH TO PERSIST ACROSS THE FORECAST AREA THRU THE END OF THE WEEK. MODELS ARE IN GOOD AGREEMENT WITH A CUTOFF LOW FORMING OFF THE SOUTHEAST COAST THURSDAY. WITH WEAK STEERING FLOW UNDERNEATH THE UPPER RIDGE, THE LOW IS NOT EXPECTED TO MAKE MUCH ADVANCEMENT TOWARD OUR AREA, RESULTING IN A DRY FORECAST FOR THURSDAY AND FRIDAY. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDS ARE EXPECTED THRU THE TAF PD AS HIGH PRES BUILDS IN FROM THE W. THERE WILL BE SOME LINGERING SC AT TIMES THRU THE DAY BEFORE THE SKY BECOMES MAINLY CLR OVERNIGHT. WIND WILL SHIFT FROM NELY TO ELY AND EVENTUALLY S DURG THE DAY AND BECOME LIGHT OVERNIGHT. SPEEDS WILL REMAIN LESS THAN 10 KT. A SEA BREEZE FRONT IS EXPECTED TO WORK ITS WAY INLAND FROM THE CST DURG THE AFTN. OUTLOOK... SUNDAY AND MONDAY...VFR. LIGHT NW WINDS SUNDAY WILL BECOME SWLY AND INCREASE ON MONDAY. GUSTS TO 20 KT POSSIBLE MONDAY AFTERNOON. TUESDAY AND WEDNESDAY...PREDOMINATELY VFR. BRIEF/LOCAL RESTRICTIONS IN SCT SHOWERS AND ISO TSTMS AS A COLD FRONT DROPS SOUTHWARD AND THEN STALLS OVER THE AREA. BEST CHANCE FOR PRECIP WOULD BE TUESDAY AFTERNOON THRU WEDNESDAY MORNING. && .MARINE... WE MADE A COUPLE OF CHANGES TO THE WINDS FOR THIS AFTERNOON AND EVENING BASED ON LATEST 12Z NAM AND SOME OF THE LATEST HRRR AND RAP AS THEY HAVE A DECENT WIND SHIFT/ SEA AND BAY BREEZE FRONT PREDICTED TO DEVELOP. WE WILL EXTEND THE SCA FOR A FEW MORE HOURS AS OBSERVED SEAS ARE ABOUT A FOOT ABOVE WAVE WATCH GUIDANCE. ONCE THIS CURRENT SCA COMES DOWN, NO ADDITIONAL MARINE HEADLINES ARE EXPECTED IN THE NR OR SHORT TERM PDS. OUTLOOK... SUNDAY THROUGH WEDNESDAY...WINDS AND WAVES WILL PREDOMINATELY STAY BELOW SCA CRITERIA. S-SW FLOW WILL INCREASE TO 15-20 KT MONDAY AFTERNOON THRU WEDNESDAY BUT THE WARM AIR ATOP THE COLDER WATERS WILL NOT PROVIDE MUCH OPPORTUNITY FOR STRONGER WINDS ALOFT TO MIX DOWN TO THE SURFACE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ452>455. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ451. && $$ SYNOPSIS...KLEIN NEAR TERM...GIGI/NIERENBERG SHORT TERM...NIERENBERG LONG TERM...KLEIN AVIATION...KLEIN/NIERENBERG MARINE...GIGI/KLEIN/NIERENBERG
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1100 AM EDT SAT MAY 2 2015 .SYNOPSIS... LOW PRESSURE OFF THE NORTH CAROLINA COAST WILL MOVE FARTHER OUT TO SEA TODAY. AN EXPANSIVE AREA OF HIGH PRESSURE WILL REMAIN IN CONTROL OF THE EASTERN THIRD OF THE COUNTRY THIS WEEKEND. THE CENTER OF THE HIGH WILL SHIFT OFFSHORE SUNDAY NIGHT AND MONDAY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY NIGHT. THIS FRONT IS EXPECTED TO WEAKEN AND STALL OVER THE AREA TUESDAY INTO WEDNESDAY. HIGH PRESSURE BUILDS BACK INTO THE AREA LATE IN THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MORNING CLOUDS HAVE PRETTY MUCH DISSIPATED ACROSS OUR CWA. MORNING SOUNDINGS DO SHOW CONVECTIVE TEMPS BEING REACHED. MODELING STILL SHOWING A LEE SIDE TROF DEVELOPING THIS AFTERNOON, BUT LAST FEW RAP AND HRRR NOT THAT ENTHUSED ABOUT SHOWERS. WE SCALED BACK COVERAGE, TIMING AND AMOUNTS. GIVEN YESTERDAY`S RESULTS WERE LESS THAN EXPECTED, IF MESOSCALE MODELING TREND CONTINUES, WE MAY DO FURTHER SCALING BACK WITH NEXT UPDATE. 12Z SOUNDINGS SHOWING MAX TEMPS IN THE 60S FOR TODAY. GIVEN CONTINUED AIR MASS MODIFICATION AND CONVECTIVE TEMPS IN THE 60S, WE SHOULD GET TO CURRENT HIGH TEMPS AND NO CHANGES WERE MADE. HIGH PRESSURE WILL SLOWLY BUILD INTO THE REGION FROM THE W AS LOW PRES OFF THE COAST MOVES AWAY FROM THE REGION. AS A RESULT, MAINLY DRY WX AND WARMING TEMPS ARE IN STORE TODAY. WITH LIGHT FLOW, TEMPS WILL BE COOLER ALG THE CST WHERE A SEABREEZE IS EXPECTED TO DEVELOP. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/... THE SFC RIDGE WILL MOVE FURTHER INTO THE REGION TONIGHT AND EXPECT A GENLY CLEAR SKY AND NOT MUCH WIND. && .LONG TERM /SUNDAY THROUGH FRIDAY/... THE LARGE-SCALE PLAYERS NEXT WEEK INCLUDE PERSISTENT TROUGHING OVER THE WESTERN CONUS AND DOWNSTREAM RIDGING OVER MUCH OF THE EASTERN CONUS AND WESTERN ATLANTIC. THIS PATTERN WILL RESULT IN WARMER THAN NORMAL TEMPS AND FEW OPPORTUNITIES FOR PRECIPITATION FOR THE MID-ATLANTIC REGION FOR THE LONG-TERM PERIOD. MAX TEMPS GENERALLY RANGE FROM THE MID 70S TO LOWER 80S EACH DAY (EXCEPT COOLER ALONG THE COAST AND IN THE POCONOS). THE CENTER OF THE SURFACE HIGH PRESSURE AND H8 ANTICYCLONE WILL BE POSITIONED OVER THE SOUTHEAST STATES ON SUNDAY. THESE FEATURES WILL PROGRESS DOWNSTREAM TOWARD THE EAST COAST SUNDAY NIGHT AND THEN OVER THE WESTERN ATLANTIC ON MONDAY. SOUTHWESTERLY RETURN FLOW AROUND THE HIGH WILL DRAW EVEN WARMER AND SLIGHTLY MORE HUMID AIR UP THE EASTERN SEABOARD. A COLD FRONT IS EXPECTED TO DROP SOUTHWARD INTO THE REGION TUESDAY MORNING. THE COMBINATION OF UNIDIRECTIONAL W-SW FLOW ALOFT THAT BECOMES ORIENTED PARALLEL TO THE BOUNDARY AND DOWNSTREAM BLOCKING (FROM THE HIGH OVER THE WESTERN ATLANTIC AND CAROLINAS) WILL LIKELY CAUSE THE FRONT TO STALL OVER THE FORECAST AREA THRU WEDNESDAY. THE BOUNDARY WILL ALSO BECOME INCREASINGLY DIFFUSE DURING THIS TIME. THE BEST, IF NOT THE ONLY APPRECIABLE CHANCE FOR PRECIPITATION NEXT WEEK WILL BE TUESDAY-WEDNESDAY. WHILE FORCING FROM THIS DECAYING BOUNDARY ITSELF WILL BE WEAK, WE WILL HAVE TO WATCH FOR MID-LEVEL SHORTWAVE ENERGY THAT EJECTS OUT OF THE SOUTHWEST CONUS TROUGH TO RIDE ATOP THE DOWNSTREAM RIDGE AND EVENTUALLY MOVE INTO OUR AREA SOMETIME DURING THE TUESDAY AFTERNOON- WEDNESDAY MORNING PERIOD. THIS WOULD ENHANCE COVERAGE OF SHOWERS. HOWEVER, THE TIMING AND STRENGTH OF ANY SUCH IMPULSE IS STILL UNCERTAIN THIS FAR OUT, SO POPS WERE KEPT GENERALLY LOW. THE 00Z GUIDANCE PROGS THE GREATER INSTABILITY THAT MAY BE SUFFICIENT FOR CONVECTION TO BE CONFINED TO NEAR THE FRONT OWING TO MOISTURE POOLING ALONG THE BOUNDARY. KEPT CHANCES FOR THUNDERSTORMS LOW AREA WIDE DUE TO UNCERTAINTY IN THE LOCATION OF THE BOUNDARY. THE REMNANTS OF THE OLD FRONTAL BOUNDARY IS FORECAST TO BECOME WASHED OUT ACROSS THE AREA BY WEDNESDAY NIGHT. UPPER RIDGE BUILDING WILL OCCUR OVER THE MIDWEST AND MID ATLANTIC LATE IN THE WEEK. THIS ALLOWS THE WARMTH TO PERSIST ACROSS THE FORECAST AREA THRU THE END OF THE WEEK. MODELS ARE IN GOOD AGREEMENT WITH A CUTOFF LOW FORMING OFF THE SOUTHEAST COAST THURSDAY. WITH WEAK STEERING FLOW UNDERNEATH THE UPPER RIDGE, THE LOW IS NOT EXPECTED TO MAKE MUCH ADVANCEMENT TOWARD OUR AREA, RESULTING IN A DRY FORECAST FOR THURSDAY AND FRIDAY. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDS ARE EXPECTED THRU THE TAF PD AS HIGH PRES BUILDS IN FROM THE W. THERE WILL BE SOME LINGERING SC AT TIMES THRU THE DAY BEFORE THE SKY BECOMES MAINLY CLR OVERNIGHT. WIND WILL SHIFT FROM NELY TO ELY AND EVENTUALLY S DURG THE DAY AND BECOME LIGHT OVERNIGHT. SPEEDS WILL REMAIN LESS THAN 10 KT. A SEA BREEZE FRONT IS EXPECTED TO WORK ITS WAY INLAND FROM THE CST DURG THE AFTN. OUTLOOK... SUNDAY AND MONDAY...VFR. LIGHT NW WINDS SUNDAY WILL BECOME SWLY AND INCREASE ON MONDAY. GUSTS TO 20 KT POSSIBLE MONDAY AFTERNOON. TUESDAY AND WEDNESDAY...PREDOMINATELY VFR. BRIEF/LOCAL RESTRICTIONS IN SCT SHOWERS AND ISO TSTMS AS A COLD FRONT DROPS SOUTHWARD AND THEN STALLS OVER THE AREA. BEST CHANCE FOR PRECIP WOULD BE TUESDAY AFTERNOON THRU WEDNESDAY MORNING. && .MARINE... WE MADE A COUPLE OF CHANGES TO THE WINDS FOR THIS AFTERNOON AND EVENING BASED ON LATEST 12Z NAM AND SOME OF THE LATEST HRRR AND RAP AS THEY HAVE A DECENT WIND SHIFT/ SEA AND BAY BREEZE FRONT PREDICTED TO DEVELOP. WE WILL EXTEND THE SCA FOR A FEW MORE HOURS AS OBSERVED SEAS ARE ABOUT A FOOT ABOVE WAVE WATCH GUIDANCE. ONCE THIS CURRENT SCA COMES DOWN, NO ADDITIONAL MARINE HEADLINES ARE EXPECTED IN THE NR OR SHORT TERM PDS. OUTLOOK... SUNDAY THROUGH WEDNESDAY...WINDS AND WAVES WILL PREDOMINATELY STAY BELOW SCA CRITERIA. S-SW FLOW WILL INCREASE TO 15-20 KT MONDAY AFTERNOON THRU WEDNESDAY BUT THE WARM AIR ATOP THE COLDER WATERS WILL NOT PROVIDE MUCH OPPORTUNITY FOR STRONGER WINDS ALOFT TO MIX DOWN TO THE SURFACE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ452>455. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ451. && $$ SYNOPSIS...KLEIN NEAR TERM...GIGI/NIERENBERG SHORT TERM...NIERENBERG LONG TERM...KLEIN AVIATION...KLEIN/NIERENBERG MARINE...GIGI/KLEIN/NIERENBERG
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
918 AM EDT SAT MAY 2 2015 .SYNOPSIS... LOW PRESSURE OFF THE NORTH CAROLINA COAST WILL MOVE FARTHER OUT TO SEA TODAY. AN EXPANSIVE AREA OF HIGH PRESSURE WILL REMAIN IN CONTROL OF THE EASTERN THIRD OF THE COUNTRY THIS WEEKEND. THE CENTER OF THE HIGH WILL SHIFT OFFSHORE SUNDAY NIGHT AND MONDAY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY NIGHT. THIS FRONT IS EXPECTED TO WEAKEN AND STALL OVER THE AREA TUESDAY INTO WEDNESDAY. HIGH PRESSURE BUILDS BACK INTO THE AREA LATE IN THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MORNING CLOUDS HAVE PRETTY MUCH DISSIPATED ACROSS OUR CWA. MORNING SOUNDINGS DO SHOW CONVECTIVE TEMPS BEING REACHED. MODELING STILL SHOWING A LEE SIDE TROF DEVELOPING THIS AFTERNOON, BUT LAST FEW RAP AND HRRR NOT THAT ENTHUSED ABOUT SHOWERS. WE SCALED BACK COVERAGE, TIMING AND AMOUNTS. GIVEN YESTERDAY`S RESULTS WERE LESS THAN EXPECTED, IF MESOSCALE MODELING TREND CONTINUES, WE MAY DO FURTHER SCALING BACK WITH NEXT UPDATE. 12Z SOUNDINGS SHOWING MAX TEMPS IN THE 60S FOR TODAY. GIVEN CONTINUED AIR MASS MODIFICATION AND CONVECTIVE TEMPS IN THE 60S, WE SHOULD GET TO CURRENT HIGH TEMPS AND NO CHANGES WERE MADE. HIGH PRESSURE WILL SLOWLY BUILD INTO THE REGION FROM THE W AS LOW PRES OFF THE COAST MOVES AWAY FROM THE REGION. AS A RESULT, MAINLY DRY WX AND WARMING TEMPS ARE IN STORE TODAY. WITH LIGHT FLOW, TEMPS WILL BE COOLER ALG THE CST WHERE A SEABREEZE IS EXPECTED TO DEVELOP. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/... THE SFC RIDGE WILL MOVE FURTHER INTO THE REGION TONIGHT AND EXPECT A GENLY CLEAR SKY AND NOT MUCH WIND. && .LONG TERM /SUNDAY THROUGH FRIDAY/... THE LARGE-SCALE PLAYERS NEXT WEEK INCLUDE PERSISTENT TROUGHING OVER THE WESTERN CONUS AND DOWNSTREAM RIDGING OVER MUCH OF THE EASTERN CONUS AND WESTERN ATLANTIC. THIS PATTERN WILL RESULT IN WARMER THAN NORMAL TEMPS AND FEW OPPORTUNITIES FOR PRECIPITATION FOR THE MID-ATLANTIC REGION FOR THE LONG-TERM PERIOD. MAX TEMPS GENERALLY RANGE FROM THE MID 70S TO LOWER 80S EACH DAY (EXCEPT COOLER ALONG THE COAST AND IN THE POCONOS). THE CENTER OF THE SURFACE HIGH PRESSURE AND H8 ANTICYCLONE WILL BE POSITIONED OVER THE SOUTHEAST STATES ON SUNDAY. THESE FEATURES WILL PROGRESS DOWNSTREAM TOWARD THE EAST COAST SUNDAY NIGHT AND THEN OVER THE WESTERN ATLANTIC ON MONDAY. SOUTHWESTERLY RETURN FLOW AROUND THE HIGH WILL DRAW EVEN WARMER AND SLIGHTLY MORE HUMID AIR UP THE EASTERN SEABOARD. A COLD FRONT IS EXPECTED TO DROP SOUTHWARD INTO THE REGION TUESDAY MORNING. THE COMBINATION OF UNIDIRECTIONAL W-SW FLOW ALOFT THAT BECOMES ORIENTED PARALLEL TO THE BOUNDARY AND DOWNSTREAM BLOCKING (FROM THE HIGH OVER THE WESTERN ATLANTIC AND CAROLINAS) WILL LIKELY CAUSE THE FRONT TO STALL OVER THE FORECAST AREA THRU WEDNESDAY. THE BOUNDARY WILL ALSO BECOME INCREASINGLY DIFFUSE DURING THIS TIME. THE BEST, IF NOT THE ONLY APPRECIABLE CHANCE FOR PRECIPITATION NEXT WEEK WILL BE TUESDAY-WEDNESDAY. WHILE FORCING FROM THIS DECAYING BOUNDARY ITSELF WILL BE WEAK, WE WILL HAVE TO WATCH FOR MID-LEVEL SHORTWAVE ENERGY THAT EJECTS OUT OF THE SOUTHWEST CONUS TROUGH TO RIDE ATOP THE DOWNSTREAM RIDGE AND EVENTUALLY MOVE INTO OUR AREA SOMETIME DURING THE TUESDAY AFTERNOON- WEDNESDAY MORNING PERIOD. THIS WOULD ENHANCE COVERAGE OF SHOWERS. HOWEVER, THE TIMING AND STRENGTH OF ANY SUCH IMPULSE IS STILL UNCERTAIN THIS FAR OUT, SO POPS WERE KEPT GENERALLY LOW. THE 00Z GUIDANCE PROGS THE GREATER INSTABILITY THAT MAY BE SUFFICIENT FOR CONVECTION TO BE CONFINED TO NEAR THE FRONT OWING TO MOISTURE POOLING ALONG THE BOUNDARY. KEPT CHANCES FOR THUNDERSTORMS LOW AREA WIDE DUE TO UNCERTAINTY IN THE LOCATION OF THE BOUNDARY. THE REMNANTS OF THE OLD FRONTAL BOUNDARY IS FORECAST TO BECOME WASHED OUT ACROSS THE AREA BY WEDNESDAY NIGHT. UPPER RIDGE BUILDING WILL OCCUR OVER THE MIDWEST AND MID ATLANTIC LATE IN THE WEEK. THIS ALLOWS THE WARMTH TO PERSIST ACROSS THE FORECAST AREA THRU THE END OF THE WEEK. MODELS ARE IN GOOD AGREEMENT WITH A CUTOFF LOW FORMING OFF THE SOUTHEAST COAST THURSDAY. WITH WEAK STEERING FLOW UNDERNEATH THE UPPER RIDGE, THE LOW IS NOT EXPECTED TO MAKE MUCH ADVANCEMENT TOWARD OUR AREA, RESULTING IN A DRY FORECAST FOR THURSDAY AND FRIDAY. && .AVIATION /13Z SATURDAY THROUGH WEDNESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDS ARE EXPECTED THRU THE TAF PD AS HIGH PRES BUILDS IN FROM THE W. THERE WILL BE SOME LINGERING SC AT TIMES THRU THE DAY BEFORE THE SKY BECOMES MAINLY CLR OVERNIGHT. WIND WILL SHIFT FROM NELY TO ELY AND EVENTUALLY S DURG THE DAY AND BECOME LIGHT OVERNIGHT. SPEEDS WILL REMAIN LESS THAN 10 KT. A SEA BREEZE FRONT IS EXPECTED TO WORK ITS WAY INLAND FROM THE CST DURG THE AFTN. OUTLOOK... SUNDAY AND MONDAY...VFR. LIGHT NW WINDS SUNDAY WILL BECOME SWLY AND INCREASE ON MONDAY. GUSTS TO 20 KT POSSIBLE MONDAY AFTERNOON. TUESDAY AND WEDNESDAY...PREDOMINATELY VFR. BRIEF/LOCAL RESTRICTIONS IN SCT SHOWERS AND ISO TSTMS AS A COLD FRONT DROPS SOUTHWARD AND THEN STALLS OVER THE AREA. BEST CHANCE FOR PRECIP WOULD BE TUESDAY AFTERNOON THRU WEDNESDAY MORNING. && .MARINE... WE WILL EXTEND THE SCA FOR A FEW MORE HOURS AS OBSERVED SEAS ARE ABOUT A FOOT ABOVE WAVE WATCH GUIDANCE. ONCE THIS CURRENT SCA COMES DOWN, NO ADDITIONAL MARINE HEADLINES ARE EXPECTED IN THE NR OR SHORT TERM PDS. OUTLOOK... SUNDAY THROUGH WEDNESDAY...WINDS AND WAVES WILL PREDOMINATELY STAY BELOW SCA CRITERIA. S-SW FLOW WILL INCREASE TO 15-20 KT MONDAY AFTERNOON THRU WEDNESDAY BUT THE WARM AIR ATOP THE COLDER WATERS WILL NOT PROVIDE MUCH OPPORTUNITY FOR STRONGER WINDS ALOFT TO MIX DOWN TO THE SURFACE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ452>455. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ451. && $$ SYNOPSIS...KLEIN NEAR TERM...GIGI/NIERENBERG SHORT TERM...NIERENBERG LONG TERM...KLEIN AVIATION...KLEIN/NIERENBERG MARINE...GIGI/KLEIN/NIERENBERG
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
903 PM EDT SUN MAY 3 2015 .UPDATE... 01Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A DRY AND ZONAL MID/UPPER LEVEL FLOW OVER THE FLORIDA PENINSULA THIS EVENING. WHILE IT IS STILL DRY AND BENIGN OVER OUR HEADS...SOUTHERN STREAM ENERGY IS COMING TOGETHER SLOWLY TO OUR SOUTH OVER CUBA AND THE FLORIDA STRAITS. STILL SOME UNCERTAINLY TO JUST HOW THIS ENERGY WILL EVOLVE DURING THE NEXT COUPLE OF DAYS...HOWEVER MANY OF THE GUIDANCE MEMBERS HAVE BEEN CONSISTENT IN THE DEVELOPMENT OF LOW PRESSURE OFF THE FLORIDA EAST COAST. THE STRENGTH AND ORGANIZATION OF THIS LOW ARE NOT WELL REPRESENTED BETWEEN THE GUIDANCE MEMBERS. HOWEVER...AT LEAST AT THE MOMENT...ALL THE GUIDANCE IS KEEPING THE INCLEMENT WEATHER ASSOCIATED WITH THIS POTENTIAL LOW GENERALLY EAST OF OUR ZONES. STILL PLENTY OF TIME TO WATCH THE EVOLUTION OF THIS SYSTEM AND WHETHER OR NOT IT WILL INTRODUCE SOME ADDED MOISTURE AND SHOWER POTENTIAL DURING THE MID-WEEK PERIOD. IN THE SHORT TERM HOWEVER...THE NEXT 24-36 HOURS ARE LOOKING QUIET IN TERMS OF SENSIBLE WEATHER. THE ONLY REAL FORECAST ISSUE WILL BE THE DEVELOPMENT OF YET ANOTHER EASTERLY WIND SURGE OVERNIGHT INTO EARLY MONDAY MORNING ACROSS THE EASTERN GULF OF MEXICO. THESE NOCTURNAL SURGES ARE ASSOCIATED WITH THE POSITION OF THE SURFACE RIDGE TO THE NORTH OF THE FLORIDA PENINSULA. THIS RIDGE IS EXPECTED TO HOLD IN PLACE THROUGH MONDAY NIGHT...SO AFTER WIDESPREAD CAUTIONARY TO ADVISORY LEVEL WINDS OVER THE MARINE AREA TONIGHT...ANOTHER ROUND OF HEADLINE WINDS APPEARS LIKELY FOR MONDAY NIGHT THROUGH EARLY TUESDAY MORNING. THE FORECAST FOR MONDAY LOOKS SIMILAR TO WHAT WE EXPERIENCED ON SUNDAY...WITH PERHAPS A BIT MORE IN THE WAY OF FAIR WEATHER CUMULUS DEVELOPING FOR THE LATE MORNING/AFTERNOON HOURS. THE EASTERLY SYNOPTIC FLOW SHOULD AGAIN GENERALLY BE STRONG ENOUGH TO PREVENT ANY SEA-BREEZE DEVELOPMENT...OR AT LEAST KEEP THE BOUNDARY OFFSHORE. HIGH TEMPERATURES IN THE LOWER TO MIDDLE 80S APPEAR COMMON. && .AVIATION... VFR CONDITIONS WILL PREVAIL FOR THE DURATION OF THE TAF PERIOD ACROSS WEST-CENTRAL AND SOUTHWEST FLORIDA. ONLY AVIATION CONCERN WILL BE GUSTY EASTERLY WINDS DURING TUESDAY. WIND GUSTS OVER 20 KNOTS ARE CERTAINLY POSSIBLE...ESPECIALLY FROM KSRQ SOUTHWARD TO THE KFMY/KRSW. CUMULUS FIELD WILL DISSIPATE OVERNIGHT WITH THE SETTING OF THE SUN...BUT RETURN FOR THE LATE MORNING AND AFTERNOON HOURS TUESDAY. && .MARINE... HIGH PRESSURE NORTH OF THE COASTAL WATERS WILL STRENGTHEN AND HOLD IN PLACE THROUGH THE FIRST HALF OF THE WEEK...WITH NORTHEASTERLY TO EASTERLY WINDS CONTINUING. EASTERLY SURGES WILL BRING WIND SPEEDS UP TO AT LEAST EXERCISE CAUTION LEVELS...WITH PERIODS OF ADVISORY LEVEL WINDS EACH OF THE NEXT COUPLE NIGHTS. THE PRESSURE GRADIENT IS THEN EXPECTED TO RELAX SLIGHTLY DURING THE SECOND HALF OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... TPA 65 86 67 85 / 0 0 0 30 FMY 63 86 66 85 / 0 0 0 50 GIF 62 84 64 84 / 0 0 0 30 SRQ 63 87 66 86 / 0 0 0 40 BKV 57 84 59 85 / 0 0 0 10 SPG 69 84 70 85 / 0 0 0 30 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...SMALL CRAFT ADVISORY UNTIL 8 AM EDT MONDAY FOR COASTAL WATERS FROM BONITA BEACH TO ENGLEWOOD FL OUT 20 NM- COASTAL WATERS FROM ENGLEWOOD TO TARPON SPRINGS FL OUT 20 NM-COASTAL WATERS FROM TARPON SPRINGS TO SUWANNEE RIVER FL OUT 20 NM-WATERS FROM BONITA BEACH TO ENGLEWOOD FL OUT 20 TO 60 NM-WATERS FROM ENGLEWOOD TO TARPON SPRINGS FL OUT 20 TO 60 NM-WATERS FROM TARPON SPRINGS TO SUWANNEE RIVER FL OUT 20 TO 60 NM. SMALL CRAFT ADVISORY UNTIL 4 AM EDT MONDAY FOR TAMPA BAY WATERS. && $$ UPDATE/AVIATION/MARINE...14/MROCZKA
AREA FORECAST DISCUSSION
NWS LINCOLN IL
900 PM CDT SUN MAY 3 2015 .UPDATE... ISSUED AT 852 PM CDT SUN MAY 3 2015 CONVECTION CONTINUES TO FIRE THIS EVENING ALONG A FRONTAL BOUNDARY EXTENDING FROM NORTHWEST ONTARIO INTO THE CENTRAL PLAINS. THE NORTHERN PORTION THE LINE, WELL NORTH OF THE FORECAST AREA, IS MAKING THE MOST RAPID EASTWARD PROGRESS. THIS IS NOT SURPRISING GIVEN THE STRONGER WIND FIELDS IN THAT AREA, AND THE FORECAST WEST-EAST ORIENTATION OF THE FRONTAL BOUNDARY THAT IS ANTICIPATED BY LATER TOMORROW. A FEW LIGHT SHOWERS ARE PUSHING INTO THE WESTERN PORTIONS OF THE FORECAST AREA WELL IN THE PRE-FRONTAL WARM SECTOR, AND THIS SHOULD CONTINUE TO WANE WITH THE LOSS OF DIURNAL HEATING. THE CONVECTION ALONG THE FRONT WILL CONTINUE TO PUSH TOWARD AT LEAST THE NORTHERN PORTION OF THE AREA BY LATE TONIGHT AS THE UPPER-LEVEL WAVE HELPING TO DRIVE THEM MOVES THROUGH. HOWEVER, THEY SHOULD ARRIVE IN A SUBSTANTIALLY WEAKENED STATE CONSIDERING THE LOSS OF DIURNAL INSTABILITY AND FORECAST WEAKENING OF THE LOW-LEVEL JET BY THE TIME THEY ARRIVE. GOING FORECAST IS IN GOOD SHAPE OVERALL. MOST SIGNIFICANT ADJUSTMENTS NEEDED ARE TOWARD PRECIPITATION TRENDS, MOST NOTABLY TO REMOVE THUNDER MENTION FROM THIS EVENING AND DELAY ARRIVAL OF THE UPSTREAM CONVECTION A BIT. && .SHORT TERM...(TONIGHT) ISSUED AT 250 PM CDT SUN MAY 3 2015 A WEAKENING SHORT WAVE OVER EASTERN IA AND NW IL BY MS RIVER WILL LIFT INTO SE WI BY SUNSET AND KEEP BEST CHANCES OF SHOWERS AND THUNDERSTORMS NORTH OF I-80 THROUGH SUNSET WITH JUST ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS OVER THE IL RIVER VALLEY. CHANCES OF SHOWERS AND THUNDERSTORMS WILL INCREASE DURING THE NIGHT ESPECIALLY OVERNIGHT OVER THE IL RIVER VALLEY WITH SLIGHT CHANCES EXTENDING AS FAR SE AT CHARLESTON/MATTOON BY SUNRISE MONDAY AS YET ANOTHER SHORT WAVE OVER EASTERN NEBRASKA TRACKS EAST TOWARD THE IA/IL BORDER BY 12Z/7 AM MONDAY. SPC KEEPS RISK OF SEVERE STORMS NW OF IL OVER NORTHERN IA, SE MN AND INTO CENTRAL WI THROUGH DAYBREAK MONDAY WHERE BETTER FORCING WILL BE AS COLD FRONT PUSHES SE INTO CENTRAL PARTS OF WI/IA BY SUNRISE MONDAY. STAYED CLOSE TO MET/MAV GUIDANCE LOWS TONIGHT IN THE UPPER 50S AND LOWER 60S WITH COOLEST READINGS IN EASTERN/SE IL. BREEZY SSW WINDS 15-25 MPH THIS AFTERNOON WILL DIMINISH SOUTH 7-14 MPH AFTER SUNSET. .LONG TERM...(MONDAY THROUGH SUNDAY) ISSUED AT 250 PM CDT SUN MAY 3 2015 MAIN FORECAST CHALLENGE WILL BE POSITION OF FRONTAL BOUNDARY AND HIGHER RAIN CHANCES LATER TONIGHT THRU MONDAY NIGHT. REMNANTS OF TODAY`S MCV SHOULD PUSH OFF TO OUR NORTHEAST PUSHING THE SHOWERS EVEN FURTHER AWAY FROM THE FORECAST AREA THIS EVENING. WEAK UPPER LEVEL DISTURBANCE OVER THE MISSOURI VALLEY HAS A FEW SHOWERS ASSOCIATED WITH IT BUT THE LAST FEW RUNS OF THE RAP AND HRRR HAVE BACKED OFF SOME ON ANY ORGANIZED SHOWER AND THUNDERSTORM THREAT WITH THAT FEATURE. IT STILL APPEARS OUR MAIN THREAT WILL COME LATER TONIGHT AND THRU THE MORNING HOURS OF MONDAY WITH REDEVELOPMENT TAKING PLACE LATER TOMORROW AFTERNOON INTO THE EVENING RIGHT ALONG THE STALLED FRONTAL BOUNDARY. HAVE TRENDED MORE TOWARDS THE HIGH RESOLUTION MODEL SOLUTIONS FROM THE NSSL-ARW AND 4KM NAM-WRF WITH RESPECT TO FRONTAL POSITION ON MONDAY AND ASSOCIATED PRECIP CHANCES ALONG IT. THE HIGHER POPS WILL REMAIN ACROSS THE NORTHERN HALF OF THE FORECAST AREA BEFORE THE BOUNDARY SHIFTS BACK NORTH LATE TUESDAY INTO WEDNESDAY AS UPPER LEVEL RIDGING BUILDS ACROSS THE REGION. SEVERE THREAT WILL BE TIED TO THE POSITION OF THE BOUNDARY MONDAY AFTERNOON AND EVENING WITH THE NAM-WRF INDICATING A 40-45 KT LOW LEVEL JET SETTING UP TONIGHT FROM NORTHERN MISSOURI NORTHEAST INTO NORTHERN IL WITH THE STRONGER 850 MB THETA-E ADVECTION AND MOISTURE TRANSPORT LOCATED FROM NORTHEAST MISSOURI INTO NORTHERN IL. STORMS SHOULD DEVELOP WELL OUT TO OUR WEST AND NORTHWEST LATER THIS EVENING AND THEN TRANSLATE EAST AND SOUTHEAST INTO OUR NORTHERN AREAS BY LATE EVENING OR DURING THE EARLY MORNING HOURS OF MONDAY. IF A DECENT COLD POOL DEVELOPS LATER TONIGHT...THOSE STORMS MAY TRACK FURTHER SOUTH AND AFFECT THE POSITION OF THE SYNOPTIC SCALE BOUNDARY IN OUR AREA ON MONDAY/MONDAY EVENING. WITH THE WEST TO EAST BOUNDARY LOCATED ACROSS A PORTION OF THE FORECAST AREA MONDAY AFTERNOON AND EVENING...LOOK FOR STORMS TO FIRE AGAIN ALONG THE INSTABILITY AXIS WHICH SHOULD BE ALIGNED FROM NORTHERN MISSOURI INTO WEST CENTRAL IL BY MID AFTERNOON. MIXED LAYER CAPES OF 1500-2000 J/KG AND EFFECTIVE SHEAR VALUES OF 25 KTS SHOULD PROMOTE STORM ORGANIZATION WITH ISOLATED STRONG WIND GUSTS AND HAIL POSSIBLE WITH 700-500 MB LAPSE RATES OF 6.5-7 DEG/C DEPICTED ON SOUNDINGS TOMORROW AFTERNOON ACROSS THE NORTH. SCATTERED STORMS SHOULD CONTINUE MONDAY NIGHT AND THEN BEGIN TO EDGE NORTHWARD BY TUESDAY AS THE UPPER LEVEL RIDGING BEGINS TO AMPLIFY ACROSS THE MIDWEST. ONCE THE 500 MB RIDGE BUILDS OVER THE AREA ON TUESDAY...SHOWER AND THUNDERSTORM CHANCES WILL SHIFT NORTH CLOSER TO THE RETREATING SURFACE BOUNDARY. OUR NEXT THREAT WILL BE ASSOCIATED WITH A LEAD SHORTWAVE TROF THAT IS FORECAST TO EJECT NORTHEAST INTO THE SOUTHERN AND CENTRAL PLAINS ON THURSDAY WITH THE HIGHEST POPS...AT LEAST INITIALLY...ACROSS THE WEST AS MODELS SUGGEST MOST OF THE STRONGER LIFT AND INSTABILITY WILL SHIFT MORE NORTH THAN EAST. HOWEVER...OUR AREA WILL BE UNDER A SOUTHWEST FLOW ALOFT LATE IN THE WEEK AND INTO NEXT WEEKEND WITH A DEEPER UPPER LEVEL LOW FORECAST BY MEDIUM RANGE MODELS TO PUSH OUT OF THE PLAINS AND INTO THE MIDWEST BY LATE IN THE WEEKEND. UNFORTUNATELY...THIS TYPE OF A PATTERN THIS TIME OF YEAR BRINGS DAILY CHANCES FOR SHOWERS AND STORMS BUT AT LEAST THE TEMPERATURES WILL REMAIN ABOVE NORMAL. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 653 PM CDT SUN MAY 3 2015 PREDOMINANTLY VFR CONDTIONS EXPECTED ACROSS THE CENTRAL ILLINOIS TERMINALS THROUGH THE 00Z TAF VALID TIME. HOWEVER, LOWER CONDTIONS ARE POSSIBLE IN THUNDERSTORMS SHOULD THEY DIRECTLY IMPACT A TERMINAL. CONFIDENCE IN THE DETAILS IS TOO LOW TO PIN-POINT THE THREAT AT THIS TIME. AN UPPER LEVEL DISTURBANCE WILL TRACK EAST ACROSS THE MIDWEST FROM THE PLAINS LATER TONIGHT, ACCOMPANIED BY SHOWERS/STORMS. A SURFACE FRONTAL BOUNDARY, CURRENTLY STRETCHING FROM NORTHWEST ONTARIO INTO THE CENTRAL PLAINS WILL GRADUALLY LIE MORE WEST-EAST WITH TIME. IT IS CURRENTLY EXPECTED TO STALL OUT CLOSE TO BUT LIKELY NORTH OF CENTRAL ILLINOIS. THIS POSITION WOULD LIKELY KEEP MOST PRECIPITATION NORTH OF THE TERMINALS THROUGH THE PERIOD. HOWEVER, A PERIOD OF SHOWERS/STORMS IS POSSIBLE LATE TONIGHT/EARLY MONDAY WITH THE PASSAGE OF THE UPPER WAVE. HAVE ONLY INCLUDED A VCTS/VCSH MENTION AT THIS TIME GIVEN THE EXPECTED COVERAGE AND UNCERTAINTY WITH HOW FAR SOUTH THREAT WILL EXTEND. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BAK SHORT TERM...07 LONG TERM...SMITH AVIATION...BAK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
705 PM CDT SUN MAY 3 2015 .SHORT TERM...(TONIGHT) ISSUED AT 250 PM CDT SUN MAY 3 2015 A WEAKENING SHORT WAVE OVER EASTERN IA AND NW IL BY MS RIVER WILL LIFT INTO SE WI BY SUNSET AND KEEP BEST CHANCES OF SHOWERS AND THUNDERSTORMS NORTH OF I-80 THROUGH SUNSET WITH JUST ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS OVER THE IL RIVER VALLEY. CHANCES OF SHOWERS AND THUNDERSTORMS WILL INCREASE DURING THE NIGHT ESPECIALLY OVERNIGHT OVER THE IL RIVER VALLEY WITH SLIGHT CHANCES EXTENDING AS FAR SE AT CHARLESTON/MATTOON BY SUNRISE MONDAY AS YET ANOTHER SHORT WAVE OVER EASTERN NEBRASKA TRACKS EAST TOWARD THE IA/IL BORDER BY 12Z/7 AM MONDAY. SPC KEEPS RISK OF SEVERE STORMS NW OF IL OVER NORTHERN IA, SE MN AND INTO CENTRAL WI THROUGH DAYBREAK MONDAY WHERE BETTER FORCING WILL BE AS COLD FRONT PUSHES SE INTO CENTRAL PARTS OF WI/IA BY SUNRISE MONDAY. STAYED CLOSE TO MET/MAV GUIDANCE LOWS TONIGHT IN THE UPPER 50S AND LOWER 60S WITH COOLEST READINGS IN EASTERN/SE IL. BREEZY SSW WINDS 15-25 MPH THIS AFTERNOON WILL DIMINISH SOUTH 7-14 MPH AFTER SUNSET. .LONG TERM...(MONDAY THROUGH SUNDAY) ISSUED AT 250 PM CDT SUN MAY 3 2015 MAIN FORECAST CHALLENGE WILL BE POSITION OF FRONTAL BOUNDARY AND HIGHER RAIN CHANCES LATER TONIGHT THRU MONDAY NIGHT. REMNANTS OF TODAY`S MCV SHOULD PUSH OFF TO OUR NORTHEAST PUSHING THE SHOWERS EVEN FURTHER AWAY FROM THE FORECAST AREA THIS EVENING. WEAK UPPER LEVEL DISTURBANCE OVER THE MISSOURI VALLEY HAS A FEW SHOWERS ASSOCIATED WITH IT BUT THE LAST FEW RUNS OF THE RAP AND HRRR HAVE BACKED OFF SOME ON ANY ORGANIZED SHOWER AND THUNDERSTORM THREAT WITH THAT FEATURE. IT STILL APPEARS OUR MAIN THREAT WILL COME LATER TONIGHT AND THRU THE MORNING HOURS OF MONDAY WITH REDEVELOPMENT TAKING PLACE LATER TOMORROW AFTERNOON INTO THE EVENING RIGHT ALONG THE STALLED FRONTAL BOUNDARY. HAVE TRENDED MORE TOWARDS THE HIGH RESOLUTION MODEL SOLUTIONS FROM THE NSSL-ARW AND 4KM NAM-WRF WITH RESPECT TO FRONTAL POSITION ON MONDAY AND ASSOCIATED PRECIP CHANCES ALONG IT. THE HIGHER POPS WILL REMAIN ACROSS THE NORTHERN HALF OF THE FORECAST AREA BEFORE THE BOUNDARY SHIFTS BACK NORTH LATE TUESDAY INTO WEDNESDAY AS UPPER LEVEL RIDGING BUILDS ACROSS THE REGION. SEVERE THREAT WILL BE TIED TO THE POSITION OF THE BOUNDARY MONDAY AFTERNOON AND EVENING WITH THE NAM-WRF INDICATING A 40-45 KT LOW LEVEL JET SETTING UP TONIGHT FROM NORTHERN MISSOURI NORTHEAST INTO NORTHERN IL WITH THE STRONGER 850 MB THETA-E ADVECTION AND MOISTURE TRANSPORT LOCATED FROM NORTHEAST MISSOURI INTO NORTHERN IL. STORMS SHOULD DEVELOP WELL OUT TO OUR WEST AND NORTHWEST LATER THIS EVENING AND THEN TRANSLATE EAST AND SOUTHEAST INTO OUR NORTHERN AREAS BY LATE EVENING OR DURING THE EARLY MORNING HOURS OF MONDAY. IF A DECENT COLD POOL DEVELOPS LATER TONIGHT...THOSE STORMS MAY TRACK FURTHER SOUTH AND AFFECT THE POSITION OF THE SYNOPTIC SCALE BOUNDARY IN OUR AREA ON MONDAY/MONDAY EVENING. WITH THE WEST TO EAST BOUNDARY LOCATED ACROSS A PORTION OF THE FORECAST AREA MONDAY AFTERNOON AND EVENING...LOOK FOR STORMS TO FIRE AGAIN ALONG THE INSTABILITY AXIS WHICH SHOULD BE ALIGNED FROM NORTHERN MISSOURI INTO WEST CENTRAL IL BY MID AFTERNOON. MIXED LAYER CAPES OF 1500-2000 J/KG AND EFFECTIVE SHEAR VALUES OF 25 KTS SHOULD PROMOTE STORM ORGANIZATION WITH ISOLATED STRONG WIND GUSTS AND HAIL POSSIBLE WITH 700-500 MB LAPSE RATES OF 6.5-7 DEG/C DEPICTED ON SOUNDINGS TOMORROW AFTERNOON ACROSS THE NORTH. SCATTERED STORMS SHOULD CONTINUE MONDAY NIGHT AND THEN BEGIN TO EDGE NORTHWARD BY TUESDAY AS THE UPPER LEVEL RIDGING BEGINS TO AMPLIFY ACROSS THE MIDWEST. ONCE THE 500 MB RIDGE BUILDS OVER THE AREA ON TUESDAY...SHOWER AND THUNDERSTORM CHANCES WILL SHIFT NORTH CLOSER TO THE RETREATING SURFACE BOUNDARY. OUR NEXT THREAT WILL BE ASSOCIATED WITH A LEAD SHORTWAVE TROF THAT IS FORECAST TO EJECT NORTHEAST INTO THE SOUTHERN AND CENTRAL PLAINS ON THURSDAY WITH THE HIGHEST POPS...AT LEAST INITIALLY...ACROSS THE WEST AS MODELS SUGGEST MOST OF THE STRONGER LIFT AND INSTABILITY WILL SHIFT MORE NORTH THAN EAST. HOWEVER...OUR AREA WILL BE UNDER A SOUTHWEST FLOW ALOFT LATE IN THE WEEK AND INTO NEXT WEEKEND WITH A DEEPER UPPER LEVEL LOW FORECAST BY MEDIUM RANGE MODELS TO PUSH OUT OF THE PLAINS AND INTO THE MIDWEST BY LATE IN THE WEEKEND. UNFORTUNATELY...THIS TYPE OF A PATTERN THIS TIME OF YEAR BRINGS DAILY CHANCES FOR SHOWERS AND STORMS BUT AT LEAST THE TEMPERATURES WILL REMAIN ABOVE NORMAL. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 653 PM CDT SUN MAY 3 2015 PREDOMINANTLY VFR CONDTIONS EXPECTED ACROSS THE CENTRAL ILLINOIS TERMINALS THROUGH THE 00Z TAF VALID TIME. HOWEVER, LOWER CONDTIONS ARE POSSIBLE IN THUNDERSTORMS SHOULD THEY DIRECTLY IMPACT A TERMINAL. CONFIDENCE IN THE DETAILS IS TOO LOW TO PIN-POINT THE THREAT AT THIS TIME. AN UPPER LEVEL DISTURBANCE WILL TRACK EAST ACROSS THE MIDWEST FROM THE PLAINS LATER TONIGHT, ACCOMPANIED BY SHOWERS/STORMS. A SURFACE FRONTAL BOUNDARY, CURRENTLY STRETCHING FROM NORTHWEST ONTARIO INTO THE CENTRAL PLAINS WILL GRADUALLY LIE MORE WEST-EAST WITH TIME. IT IS CURRENTLY EXPECTED TO STALL OUT CLOSE TO BUT LIKELY NORTH OF CENTRAL ILLINOIS. THIS POSITION WOULD LIKELY KEEP MOST PRECIPITATION NORTH OF THE TERMINALS THROUGH THE PERIOD. HOWEVER, A PERIOD OF SHOWERS/STORMS IS POSSIBLE LATE TONIGHT/EARLY MONDAY WITH THE PASSAGE OF THE UPPER WAVE. HAVE ONLY INCLUDED A VCTS/VCSH MENTION AT THIS TIME GIVEN THE EXPECTED COVERAGE AND UNCERTAINTY WITH HOW FAR SOUTH THREAT WILL EXTEND. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...07 LONG TERM...SMITH AVIATION...BAK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
256 PM CDT SAT MAY 2 2015 .SHORT TERM...(TONIGHT) ISSUED AT 255 PM CDT SAT MAY 2 2015 A WEAK SHORT WAVE OVER WESTERN IA WILL TRACK EAST TO THE IL/IA BORDER BY MIDNIGHT AND WEAKEN AS IT MOVES ACROSS CENTRAL AND NORTHERN IL OVERNIGHT. AN AREA OF SHOWERS AND ISOLATED THUNDERSTORMS OVER NORTHERN MO AND SOUTHERN IA WILL CONTINUE TO TRACK EASTWARD INTO WEST CENTRAL IL EARLY THIS EVENING BETWEEN 6-8 PM AND INTO CENTRAL IL LATER THIS EVENING AND OVERNIGHT AS SHOWERS BECOME MORE ISOLATED. HAVE 20-30% CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS FROM I-55 NW AFTER SUNSET TONIGHT AND LINGERING ISOLATED LIGHT SHOWERS UNTIL MID SUNDAY MORNING NORTH OF I-72 UNTIL WEAKENING SHORT WAVE PASSES EAST OF IL INTO WESTERN IN BY MIDDAY SUNDAY. MID AND HIGH CLOUDS WILL CONTINUE TO INCREASE FROM THE WEST LATE THIS AFTERNOON AND EVENING WITH SOUTHEAST IL SEEING LESS CLOUD COVER TONIGHT SINCE CLOSER TO HIGH PRESSURE RIDGE OVER SOUTHEAST STATES. LOWS TONIGHT IN THE LOW TO MID 50S WITH COOLEST READINGS NEAR WABASH RIVER WHERE LIGHER WINDS AND LESS CLOUD COVER TONIGHT. SSW WINDS 7- 14 MPH AND GUSTS 15-20 MPH THIS AFTERNOON TO DIMINISH LESS THAN 10 MPH AFTER SUNSET AND VEER SSE. && .LONG TERM...(SUNDAY THROUGH SATURDAY) ISSUED AT 255 PM CDT SAT MAY 2 2015 IOWA SHORTWAVE FORECAST BY MODELS TO TRACK ACROSS THE AREA OVERNIGHT AND INTO THE MORNING HOURS OF SUNDAY BRINGING ISOLATED SHOWERS TO PARTS OF THE FORECAST AREA. SOUNDINGS STILL SHOWING A VERY DRY PROFILE BELOW 850 MB INTO SUNDAY MORNING BEFORE THE WAVE SHIFTS OFF TO OUR EAST DURING THE MORNING. WILL KEEP SLIGHTS GOING FOR A FEW HOURS IN THE MORNING BEFORE THE WAVE MOVES OUT OF THE AREA. OUR ATTENTION THEN TURNS TO A NORTHERN STREAM SHORTWAVE THAT WILL DRAG A COLD FRONT SOUTHEAST INTO THE LOWER GREAT LAKES LATE SUNDAY AND INTO MONDAY INCREASING THE CHANCES FOR MORE WIDESPREAD SHOWERS AND STORMS...ESPECIALLY OVER THE NORTHERN HALF OF THE FORECAST AREA WHERE THE BOUNDARY IS FORECAST TO BECOME STATIONARY. AFTER OUR SLIGHT CHANCES SUNDAY MORNING...THE REST OF THE DAY LOOKS QUIET AND WARM WITH A GUSTY SOUTH TO SOUTHWEST WIND HELPING TO PUSH AFTERNOON TEMPS INTO THE UPPER 70S TO LOWER 80S. POPS START TO RAMP UP SUNDAY NIGHT ACROSS THE FAR NORTHWEST AS THE BOUNDARY EDGES SLOWLY SOUTHEAST WITH MODELS TRENDING SLOWER WITH THE FRONTAL BOUNDARY AND QPF ALONG IT. MAY HAVE TO SLOW THE ONSET OF THE SHOWERS EVEN MORE IF THESE TRENDS CONTINUE. BETTER LOW LEVEL JET SUPPORT AND 850 MB THETA-E ADVECTION REMAINS OUT TO OUR NORTHWEST LATE SUNDAY NIGHT WITH MOST MODELS SUGGESTING THAT A CLUSTER OF STORMS...AT LEAST WHAT`S LEFT OF THEM...WILL APPROACH OUR FAR NORTHWEST COUNTIES WELL AFTER MIDNIGHT SUNDAY NIGHT. THE SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE TO SPREAD SLOWLY SOUHTEAST ON MONDAY AND INTO MONDAY NIGHT WITH THE HIGHER THREAT BEING AGAIN WHERE THE BOUNDARY IS EXPECTED TO BECOME STATIONARY... WHICH AT THIS TIME LOOKS TO BE NORTH OF I-72. FORECAST SOUNDINGS SHOWING MIXED LAYER CAPES OF AROUND 1500 J/KG MONDAY AFTERNOON INTO EARLY MONDAY EVENING WITH THE STRONGER 500 MB WIND FLOW TO OUR NORTH WITH 30-35 KTS FORECAST. SPC HAS A LARGE AREA OF MARGINAL RISK FOR SEVERE STORMS MONDAY AFTERNOON AND EVENING STRETCHING FROM THE SOUTHERN PLAINS UP ACROSS THE NORTHERN HALF OF OUR CWA. SEVERE PARAMETERS BORDERLINE AT THIS TIME BUT WITH THE BOUNDARY IN THE AREA AND FORECAST CONVECTIVE TEMPS AROUND 80...MULTI-CELL STORMS SHOULD DEVELOP DURING THE AFTERNOON AND CONTINUE INTO THE EVENING WITH THE POSSIBILITY FOR SOME GUSTY WINDS...HAIL AND HEAVY RAINFALL WITH SOME OF THE MORE ORGANIZED CLUSTERS OF STORMS THAT FORM ALONG THE STALLED FRONTAL BOUNDARY. MODELS SUGGEST THE BOUNDARY WILL SHIFT NORTH OF THE AREA STARTING ON TUESDAY AS UPPER LEVEL HEIGHTS BUILD IN RESPONSE TO A RATHER VIGOROUS UPPER WAVE THAT WILL BE PUSHING ACROSS THE SOUTHERN ROCKIES AND EVENTUALLY SWING NORTHEAST INTO THE PLAINS BY MID TO LATE IN THE UPCOMING WORK WEEK. WILL INDICATE A BIT OF A LULL IN THE SHOWER AND STORM CHANCES UNTIL LATE THURSDAY OR FRIDAY WHEN THE WAVE WILL APPROACH OUR AREA. TEMPERATURES LOOK TO BE ABOVE NORMAL THRU THE WORK WEEK WITH AFTERNOON HIGHS CLIMBING INTO THE UPPER 70S TO LOWER 80S...WHILE EARLY MORNING LOWS ONLY DROP OFF INTO THE UPPER 50S TO LOWER 60S TUESDAY MORNING...WITH MOST OF OUR AREA SEEING LOW TEMPERATURES IN THE LOW TO MID 60S FOR THE REMAINDER OF THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1255 PM CDT SAT MAY 2 2015 VFR CONDITIONS ARE FORECAST TO CONTINUE ACROSS THE CENTRAL IL AIRPORTS THROUGH SUNDAY. SCATTERED TO BROKEN MID/HIGH CLOUDS ABOVE 7K FT WILL SPREAD EAST ACROSS CENTRAL IL THIS AFTERNOON. WEAK SHORT WAVE OVER WESTERN IA TO TRACK EAST TOWARD THE IL/IA BORDER BY MIDNIGHT TONIGHT AND WEAKEN FURTHER. VCSH AT PIA AFTER 02Z AND AS FAR EAST AT I-55 AT BMI AND SPI AFTER 04Z TONIGHT. LATEST HRRR AND RAP MODELS SHOW ISOLATED SHOWERS THIS FAR EAST DURING 2ND HALF OF EVENING WHILE NAM MODEL (WHICH INITIALIZED TOO DRY) KEEPS CENTRAL IL DRY NEXT 24 HOURS. SSW WINDS 9-13 KTS THIS AFTERNOON TO BE SSE 4-8 KTS TONIGHT AND SSW 9-13 KTS SUNDAY WITH FEW-SCT CUMULUS CLOUDS 5-6 KFT AND SOME BROKEN MID LEVEL CLOUDS AT OR ABOVE 10K FT. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...07 LONG TERM...SMITH AVIATION...07
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1255 PM CDT SAT MAY 2 2015 .UPDATE... ISSUED AT 1045 AM CDT SAT MAY 2 2015 FORECAST GENERALLY ON TRACK THOUGH WILL NEED TO UPDATE FOR MORE CLOUD COVER THIS AFTERNOON ESPECIALLY WESTERN AREAS. SHOWERS AND ISOLATED THUNDERSTORMS SHOULD STAY WEST OF CENTRAL IL THROUGH SUNSET PER LATEST HIGH RESOLUTION MODELS. MILDER HIGHS IN THE MID TO UPPER 70S THIS AFTERNOON WITH PARTLY TO MOSTLY SUNNY SKIES AND SOUTHWEST WINDS 5-15 MPH THIS AFTERNOON. 1022 MB HIGH PRESSURE RIDGE OVER KY AND TN RIVER VALLEY WILL SHIFT SE OF KY/TN BY THIS EVENING WHILE WEAK UPPER LEVEL RIDGE INTO IL TODAY. THIS WILL KEEP CENTRAL AND SOUTHEAST IL DRY TODAY WITH INCREASING SW WINDS BRINGING IN MILDER TEMPERATURES. WEAK SHORT WAVE NEAR IA/NE BORDER TO TRACK EAST INTO EASTERN IA BY MID EVENING WITH SHOWERS AND ISOLATED THUNDERSTORMS SPREADING EASTWARD ACROSS SOUTHERN IA AND NORTHERN MO THIS AFTERNOON, AND INTO WEST CENTRAL IL AFTER SUNSET. && .SHORT TERM...(TODAY) ISSUED AT 331 AM CDT SAT MAY 2 2015 A SHORTWAVE HIGH PRESSURE RIDGE EMBEDDED IN WESTERLY FLOW ALOFT WILL BE THE DOMINATING WEATHER FEATURE TODAY...PROMOTING GENERAL SUBSIDENCE AND LIGHT CLOUD COVER THROUGH THE DAY. WITH SLOWLY MOISTENING LOWER LEVELS...THERE SHOULD BE ENOUGH MOISTURE FOR A SHALLOW SCATTERED CUMULUS LAYER DEVELOPING IN LATE MORNING THROUGH AFTERNOON. HIGH CLOUD COVER ASSOCIATED WITH AN APPROACHING UPPER LEVEL DISTURBANCE WILL START TO SPREAD INTO CENTRAL IL LATE IN THE AFTERNOON. RELATIVELY LIGHT SOUTHWESTERLY WINDS AROUND 6 TO 10 MPH EXPECTED TODAY...ALONG WITH HIGH TEMPERATURES REACHING THE MID 70S. .LONG TERM...(TONIGHT THROUGH FRIDAY) ISSUED AT 331 AM CDT SAT MAY 2 2015 HIGH PRESSURE RIDGE AXIS FROM THE WESTERN GULF COAST UP INTO THE GREAT LAKES THIS MORNING KEEPING THE WEATHER MILD IN THE SHORT TERM THROUGH THE WEEKEND. QUASI ZONAL FLOW OVER THE WESTERN HALF OF THE COUNTRY AND INTO THE PLAINS SLOWLY SHIFTS TO THE MIDWEST LATER IN THE WEEKEND. WITH THE ZONAL FLOW ALOFT...A FRONT SETTLES INTO THE REGION AND STALLS OUT...BECOMING A FOCUS FOR STORMS AND PRECIP FOR THE START OF THE WORK WEEK. PRECIP CHANCES HOLDING ON UNTIL A RIDGE BEGINS TO BUILD INTO THE MIDWEST FROM THE SOUTHEASTERN CONUS. INFLUENCE OF THE RIDGE ERODING THE SOUTHERN EXTENT OF THE SHOWERS AT LEAST TUES NIGHT THROUGH WED NIGHT. MODELS SHIFT GEARS AGAIN ON THE OTHER SIDE OF MIDWEEK, GOING TO A MORE SOUTHWESTERLY FLOW AND AN ACTIVE WEATHER PATTERN AS WAVES CONTINUE TO RIPPLE AROUND THE SWRN LOW AND INTO THE MIDWEST. A RATHER WET FORECAST OVERALL, WITH SEVERAL DIFFERENT PATTERNS ESTABLISHING THEMSELVES...AND KEEPING SHOWERS AND THUNDERSTORMS IN THE OUTLOOK. NOT MUCH IN THE WAY OF MODEL DIFFERENCES OVERALL AND GUIDANCE SEEMS TO BE TRENDING WARMER. ECMWF 850MB TEMPS STAYING IN THE 11-13C THROUGH MIDWEEK...EVEN WARMER TO WRAP UP THE WORK WEEK...BUT THOSE WARMER TEMPS ALOFT WILL BE COUNTERED BY PRECIP IN THE MORE ACTIVE SWRLY PATTERN. OVERALL, CONCERN IN THE FORECAST CENTERS ON THE LOCATION OF THE FRONT STALLING OUT AND THE SUBSEQUENT FOCUS FOR THE PRECIPITATION/TRAINING. NOT MUCH IN THE WAY OF SEVERE WEATHER EXPECTED AT THIS POINT...BUT PROLONGED RAINFALL MAY NEED TO BE WATCHED A BIT FOR MON AND TUES, PARTICULARLY IN THE NORTHERN HALF OF THE STATE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1255 PM CDT SAT MAY 2 2015 VFR CONDITIONS ARE FORECAST TO CONTINUE ACROSS THE CENTRAL IL AIRPORTS THROUGH SUNDAY. SCATTERED TO BROKEN MID/HIGH CLOUDS ABOVE 7K FT WILL SPREAD EAST ACROSS CENTRAL IL THIS AFTERNOON. WEAK SHORT WAVE OVER WESTERN IA TO TRACK EAST TOWARD THE IL/IA BORDER BY MIDNIGHT TONIGHT AND WEAKEN FURTHER. VCSH AT PIA AFTER 02Z AND AS FAR EAST AT I-55 AT BMI AND SPI AFTER 04Z TONIGHT. LATEST HRRR AND RAP MODELS SHOW ISOLATED SHOWERS THIS FAR EAST DURING 2ND HALF OF EVENING WHILE NAM MODEL (WHICH INITIALIZED TOO DRY) KEEPS CENTRAL IL DRY NEXT 24 HOURS. SSW WINDS 9-13 KTS THIS AFTERNOON TO BE SSE 4-8 KTS TONIGHT AND SSW 9-13 KTS SUNDAY WITH FEW-SCT CUMULUS CLOUDS 5-6 KFT AND SOME BROKEN MID LEVEL CLOUDS AT OR ABOVE 10K FT. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...07 SHORT TERM...ONTON LONG TERM...HJS AVIATION...07
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1148 PM CDT FRI MAY 1 2015 .SYNOPSIS... ISSUED AT 321 PM CDT FRI MAY 1 2015 WEAK FRONTAL BOUNDARY WILL DISSIPATE OVER IOWA TONIGHT AS A FRONTAL BOUNDARY DEVELOPS TO THE NORTHWEST ON SATURDAY. THIS FRONT WILL MOVE SOUTHEAST THROUGH THE AREA SUNDAY AFTERNOON AND NIGHT BEFORE STALLING. THE OVERALL WEATHER PATTERN WILL BE ACTIVE WITH THE FRONT IN THE VICINITY THROUGH THE NEXT WEEK. && .SHORT TERM /TONIGHT/... ISSUED AT 321 PM CDT FRI MAY 1 2015 MAIN FORECAST CONCERN WILL BE PRECIPITATION CHANCES THIS EVENING AND AGAIN VERY LATE IN THE PERIOD. ONGOING PRECIPITATION ACROSS CENTRAL PORTION OF THE CWA WILL PERSIST THROUGH THE EVENING...CONTINUING TO PUSH SLOWLY SOUTHEAST. WEAK BOUNDARY AND FORCING WITH PRECIPITATION WILL CONTINUE TO WEAKEN AND WILL SEE PRECIPITATION CONTINUE TO BECOME MORE SCATTERED THROUGH THE LATE EVENING. HRRR MODEL HAS A GOOD HANDLE ON PRECIPITATION TRENDS...AND HAVE TRENDED THIS WAY FOR POPS. GIVEN CURRENT LACK OF INSTABILITY HAVE LEFT THUNDER MENTION OUT...THOUGH COULD SEE SOME ISOLATED THUNDER IN THE LATE AFTERNOON OR EARLY EVENING WITH INCREASING INSTABILITY IN THE FAR WEST. SHORTWAVE LIFTING NORTH FROM KS/NE WILL BEGIN TO PUSH INTO SOUTHWEST NEAR 12Z. HAVE CUT BACK ON POPS WITH SLIGHTLY SLOWER PROGRESSION OF WAVE AND MOISTURE NOTED...NOT PUSHING INTO CWA UNTIL AFTER 12Z. HOWEVER...PLACEMENT MAY BE TOO FAR SOUTH ACROSS THE WEST. HAVE KEPT OVERNIGHT LOW TEMPERATURES DOWN A DEGREE OR TWO GIVEN HOW PRECIPITATION LIMITED DAYTIME HIGHS...AND EXPECT CLEARING SKIES ACROSS THE NORTH TONIGHT. .LONG TERM /SATURDAY THROUGH FRIDAY/... ISSUED AT 321 PM CDT FRI MAY 1 2015 CONTINUED WAA AND POCKETS OF STRONGER THETA-E WILL DOMINATE THROUGH THE NEXT WEEK. A WEAK FEATURE WILL MOVE THROUGH THE AREA ON SATURDAY BRINGING WIDELY SCATTERED SHOWERS AND THUNDERSTORMS...BUT NOTHING TO REALLY FOCUS ON WITH THIS. SUNDAY LOOKS TO BE MORE ACTIVE AS DEW POINTS COME UP AND A STRONGER FRONT MOVES IN. CAPE RISES TO AROUND 2000 J/KG OR SO BY MID DAY SUNDAY WITH LITTLE RESIDUAL CAP. OTHER PARAMETERS ARE NOT AS FAVORABLE WITH INFLOW RELATIVELY WEAK AND OVERALL CONVERGENCE ALONG THE FRONT NOT OPTIMAL. STILL, THUNDER CHANCES ARE DECENT AND IT APPEARS THAT MARGINAL TO SLIGHT THREAD FOR SEVERE LOOKS REASONABLE. THE REST OF THE WEEK WILL BE WARMER THAN NORMAL AND WET. TROUGH IN THE WEST WILL SEND OUT PERIODIC PIECES WITH THE NEXT STRONGER PIECE ARRIVING ABOUT THURSDAY...THE NEXT BEYOND THE FORECAST PERIOD. THOUGH THE SEVERE THREAT LOOKS RELATIVELY LOW...THE CHANCES FOR WIDESPREAD RAINFALL IN EXCESS OF 2 INCHES IN A WEEK IS PRETTY GOOD. DO NOT EXPECT THE RAINFALL TO BE A PROBLEM...BUT IT WILL PUT A CRIMP IN PLANTING PROGRESS. && .AVIATION...02/06Z ISSUED AT 1148 PM CDT FRI MAY 1 2015 VERY LIGHT SHOWERS TIED TO A WEAK DISTURBANCE AND SOME WEAK FORCING ACROSS THE AREA WILL CONTINUE TO WANE OVER THE NEXT COUPLE OF HOURS. BETWEEN 12Z AND 15Z ANOTHER UPPER LEVEL DISTURBANCE AND SOME FORCING TIED TO IT WILL SHIFT ACROSS CENTRAL/SOUTHERN IOWA. THERE SHOULD BE SOME SHOWERS ASSOCIATED WITH THIS FEATURE AS WELL. WE WILL BE A BIT MORE UNSTABLE TOMORROW SO THUNDERSTORMS WILL DEVELOP AS WELL BUT LOW LEVEL MOISTURE WILL BE LACKING SO WE ARE NOT LOOKING FOR MUCH IN THE WAY OF PRECIP OR LOW CIGS DURING THE FORECAST PERIOD. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MS MAY 15 SHORT TERM...AWB LONG TERM...MS MAY 15 AVIATION...FAB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
534 PM MDT SUN MAY 3 2015 .UPDATE... ISSUED AT 534 PM MDT SUN MAY 3 2015 ISSUED MINOR FORECAST UPDATE TO ACCOUNT FOR LATEST TRENDS WITH POPS...WINDS AND SKY. SLOW MOVING THUNDERSTORMS HAVE DEVELOPED SOUTH OF INTERSTATE 70. DUE TO SLOW MOVEMENT...RAINS HAVE BEEN HEAVY AT TIMES. WILL NEED TO REFINE QPF AND QPE SHORTLY. STORMS HAVE BEEN SUB-SEVERE SO FAR BUT A FEW HAVE APPROACHED SEVERE LIMITS. MAIN THREATS WITH THESE STORMS IS DAMAGING WINDS AND LARGE HAIL IF THEY WERE TO BECOME SEVERE. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 224 PM MDT SUN MAY 3 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW WESTERLY FLOW IN PLACE ACROSS THE PLAINS WITH A SHORTWAVE TROUGH UPSTREAM OVER THE CENTRAL ROCKIES. AT THE SURFACE A TROUGH IS CURRENTLY IN PLACE OVER THE CWA...WITH A COLD FRONT NEAR IMPERIAL NEBRASKA EXTENDING INTO NORTHEAST COLORADO. REGIONAL RADAR SHOWS SCATTERED THUNDERSTORM ACTIVITY ALREADY MOVING OFF THE HIGHER TERRAIN IN COLORADO AND MOVING OFF THE PALMER DIVIDE TOWARDS THE WESTERN PART OF OUR CWA. THIS AFTERNOON-TONIGHT...WINDOW FOR SEVERE WEATHER APPEARS TO BE MAINLY AHEAD OF COLD FRONT WHERE MODELS HAD BEEN ADVERTISING MODERATE INSTABILITY DEVELOPING BY 00Z (MAINLY EAST OF SURFACE TROUGH). SO FAR RAP ANALYSIS SHOWS ML CAPE GENERALLY AROUND 500 J/KG LIKELY DUE TO MUCH LOWER TD VALUES AHEAD OF COLD FRONT THAN PREVIOUSLY ANTICIPATED. HRRR/RAP HAVE BEEN SHOWING ISOLATED DEVELOPMENT ALONG SURFACE TROUGH AXIS WHERE CAP HAS BEEN WEAKENED. THERE IS A WINDOW FOR INCREASING SHEER AS COLD FRONT MOVES SOUTH AND DEPENDING ON STRENGTH OF UPDRAFTS WE COULD SEE SOME ORGANIZED CELLS...OTHERWISE IT APPEARS TO BE AN ENVIRONMENT FAVORING PULSE TYPE THUNDERSTORMS THROUGH MOST OF THE NIGHT. DCAPE VALUES IN EXCESS OF 1000 J/KG DO RAISE CONCERNS FOR MICROBURST POTENTIAL AHEAD OF COLD FRONT SO EVEN WEAKER UPDRAFTS COULD PRODUCE NEAR SEVERE OR SEVERE WINDS AS THEY COLLAPSE. SHOWER AND THUNDERSTORM COVERAGE WILL INCREASE LATE THIS EVENING ALONG/NORTH OF COLD FRONT WITH INCREASING MOISTURE RETURN AND ELEVATED CAPE IN PLACE. BY LATE TONIGHT INSTABILITY BEGINS TO WANE...WHILE LARGE SCALE FORCING STARTS TO SHIFT NORTH AND EAST OF THE REGION. THIS IS WHERE MODELS DIVERGE WITH NAM CONTINUING TO INDICATE AND LULL OR DRY PERIOD WHILE ECMWF/GFS INDICATE POSSIBLE OVERRUNNING OR STRATUS/FOG/DRIZZLE DEVELOPMENT ALONG/NORTH OF THE FRONT. TOUGH CALL AND WHILE I HEDGED TOWARD THE DRY NAM AT 12Z...I COULD SEE IN THIS TYPE OF PATTERN A LIGHT PRECIP/DRIZZLE EVEN EVOLVING BY MONDAY MORNING. MONDAY...UPPER LOW OVER THE SOUTHWEST US BEGINS TO DEEPEN AND MOVE EAST WITH BETTER LARGE SCALE FORCING SPREADING OVER THE CWA BY LATE AFTERNOON. DEPENDING ON WHAT HAPPENS TO POSSIBLE STRATUS DURING THE DAY WE MAY OR MAY NOT HAVE A WINDOW FOR SEVERE THUNDERSTORMS IN THE EASTERN PART OF OUR CWA WHERE MODELS SHOW WAA AND INCREASING TDS/INSTABILITY. FURTHER NORTH AND WEST STRATUS IS MORE LIKELY TO LINGER...HOLDING TEMPS DOWN IN AND ANY INSTABILITY WOULD BE ELEVATED AND WEAKER. DEPENDING ON CHOICE IN MODEL SHOWERS/THUNDERSTORMS COULD BE POSSIBLE THROUGH THE DAY...HOWEVER BETTER CHANCES SHOULD BE TIED TO STRONGER LARGE SCALE FORCING LATER DURING THE DAY MONDAY. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 224 PM MDT SUN MAY 3 2015 SOUTHWEST FLOW WILL PRECEDE AN UPPER TROUGH THAT WILL AFFECT THE CENTRAL PLAINS TUESDAY THROUGH WEDNESDAY. SURFACE HIGH PRESSURE WILL SHIFT EAST ACROSS THE CENTRAL PLAINS MONDAY NIGHT AS LOW PRESSURE MOVES INTO COLORADO TUESDAY. LOW PRESSURE WILL REMAIN OVER COLORADO AND WESTERN KANSAS THROUGH WEDNESDAY. POPS WILL INCREASE FROM MONDAY EVENING TO OVERNIGHT AS BETTER DYNAMICS AND MOISTURE MOVE NORTH INTO THE FA. PLAN TO GO WITH CHANCE POPS ACROSS THE WESTERN PORTION OF THE FA DURING THE EVENING WITH LIKELY POPS OVER THE SOUTHEAST ZONES CLOSER TO THE SURFACE BOUNDARY. LIKELY POPS WILL SPREAD NORTH ACROSS THE FA OVERNIGHT AS VERY FAVORABLE MOISTURE AND LIFT MOVE INTO THE FA. LIKELY AND DEFINITE POPS WILL BE USED ACROSS THE ENTIRE FA TUESDAY AND TUESDAY EVENING AS GOOD DYNAMICS AND MOISTURE CONTINUE TO STREAM NORTHWARD ACROSS THE FA. PRECIPITABLE WATER VALUES ARE AROUND AN INCH SO WILL INCLUDE MODERATE RAIN IN THE GRIDS TUESDAY. POPS WILL START DECREASING TO CHANCE POPS AFTER 06Z WEDNESDAY AS THE UPPER TROUGH STARTS TO LIFT OUT OF THE AREA. SOME LIKELY POPS WILL STILL EXIST ACROSS THE NORTHERN FA WEDNESDAY AFTERNOON AS INSTABILITY INCREASES. MIN TEMPERATURES MONDAY NIGHT SHOULD COOL TO THE MID 40S IN EASTERN COLORADO AND THE MID 50S IN THE EASTERN FA. MIN TEMPERATURES TUESDAY NIGHT WILL RANGE FROM THE LOWER TO MID 50S. MAX TEMPERATURES TUESDAY SHOULD RANGE FROM 65 TO 70 AND 70 TO 75 WEDNESDAY. IN THE EXTENDED...(WEDNESDAY NIGHT THROUGH SUNDAY)...THE UPPER TROUGH LIFTS NORTHEAST WEDNESDAY NIGHT WITH SOUTHWEST FLOW FOLLOWING THROUGH SATURDAY. THE NEXT UPPER TROUGH MOVES INTO THE PLAINS SATURDAY NIGHT AND SUNDAY. SHORTWAVES MOVING THROUGH THE FLOW AND INCREASING DYNAMICS WITH THE NEXT TROUGH SATURDAY NIGHT AND SUNDAY WILL KEEP AT LEAST A CHANCE OF THUNDERSTORMS ACROSS THE FA EACH DAY. MIN TEMPERATURES THROUGH SATURDAY NIGHT SHOULD RANGE FROM 45 TO 55. MAX TEMPERATURES WILL GENERALLY RANGE FROM THE MID 60S TO THE MID 70S. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 527 PM MDT SUN MAY 3 2015 VFR CONDITIONS LIKELY END BY TOMORROW MORNING. A COLD FRONT WILL SAG SOUTH ACROSS THE FORECAST AREA TONIGHT. WITH POOLING LOW LEVEL MOISTURE...IT APPEARS LIKELY THAT STRATUS/FOG DEVELOPS IN THE VICINITY OF THE FRONT. STRATUS EXPANDS NORTH...BECOMING WIDESPREAD BY 12-14Z...THEN GRADUALLY RECEDES NORTH DURING THE DAY. COULD SEE A SCENARIO WHERE STRATUS PERSISTS THROUGHOUT THE DAY WITH LITTLE AIRMASS CHANGE. WITH RESPECT TO THUNDERSTORM CHANCES...INCREASING THREAT OF STORMS IS ANTICIPATED THIS EVENING. HOWEVER...HIGH RES MODEL GUIDANCE INDICATES A FEW ISOLATED STORMS NEAR KGLD AND KMCK WHILE A MORE ORGANIZED CLUSTER OF STORMS REMAINS JUST SOUTH. FOR NOW...MENTIONED VCTS BUT WILL MONITOR THIS CLOSELY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...RRH SHORT TERM...DR LONG TERM...FS AVIATION...RRH
AREA FORECAST DISCUSSION
NWS TOPEKA KS
630 PM CDT Sun May 3 2015 ...Update to aviation forecast discussion... .SHORT TERM...(This Evening through Monday) Issued at 328 PM CDT SUN MAY 3 2015 Zonal but weak flow aloft continues over the Central Plains between northern and southern branches with a few weak waves moving through. Appears moderate mid-level isentropic lift combined with one of these waves to spark overnight convection, with another wave keeping isolated showers going in eastern Kansas into the early afternoon. High- based nature of this activity keeping much precip from what there is in check however. Water vapor imagery suggesting a stronger wave rotating northeast out of eastern New Mexico with convection firing ahead of it into southeastern Colorado. Cold front was from northwestern Kansas into northeastern Nebraska early this afternoon with a few cumulus along it in central Nebraska. Dewpoints have dropped to around 40F in southwest Kansas with thermal ridge ahead of front pushing temp at CNK to near record levels. Precipitation chances remain the main challenge through Monday afternoon. Recent HRRR and RAP runs continue to attempt to produce convection along the front, but have been too fast to do so. With low levels rather dry to the west, the main player with convection to the west and south could be via the New Mexico wave, or other convective-induced waves from eastern Colorado. Isentropic upglide looks less impressive than this morning but some is again present and could be enough to continue or even produce convection into east central Kansas late this evening and into much of Monday. Other prime scenario for convection seems to be with eventual convection generated in eastern Nebraska sinking south into northeast Kansas on decent 850mb moisture convergence as a moderate low level jet veers with time. This could linger well into Monday morning, and with the earlier possibilities as well, have kept chance PoPs going into the morning Monday, with lesser confidence in precip in the northwest counties nearer the drier low level air. Details in precip activity Monday afternoon will be largely impacted by the earlier activity, but models increase low level moisture further, though NAM likely a bit aggressive again, with CAPE possibly near 2000 J/kg ahead of any outflow or front/effective front. Shear values again look meager to support much severe weather but some potential remains. Have kept highs cooler than today with more cloud/precip/moisture anticipated. .LONG TERM...(Monday Night through Sunday) Issued at 328 PM CDT SUN MAY 3 2015 Models continue to show an active pattern for Monday night through Sunday as they dig another closed low into the southwestern U.S. by the end of the work week. This causes mid level flow to remain from the southwest while gulf moisture continues advecting north. So there looks to be plenty of moisture available with occasional forcing mechanisms passing overhead such that there is a chance for precip in every period of the forecast. The one period with the lowest chance for precip remain Tuesday. There seems to be agreement among the models that shortwave ridge will propagate over eastern KS with some relatively dryer air moving in. Therefore have a dry forecast for northeast and east central KS. North central KS may be close enough to shortwave energy lifting north through the high plains that have kept a small chance for the western counties for Tuesday. The best chance for showers and thunderstorms appears to be late Tuesday night and Wednesday as a well defined shortwave is progged to lift across northeast KS. There are some minor differences in timing of the vort max lifting out. Nevertheless with little or no inhibition to convection expect showers and thunderstorms to overspread the area and have increased POPs into the 70 to 80 percent range. Wednesday night through Saturday does not look like it will be constant precip, but the pattern makes it difficult to say when chances are better than not. With occasional low amplitude waves within the southwest flow and a moist airmass remaining in place, the forecast has a chance for precip each day. There are even some signs of a weak frontal boundary moving into the forecast on Friday which may help focus moisture and provide some lift. Otherwise think chances could be on the increase for Saturday night and Sunday as the upper low begins to lift out of the southern Rockies. Because the GFS is a little further north and doesn`t have as much shortwave energy rotating through the southern plains, have kept POPs in the chance category for now. There should not be any big swings in temps through the period due to the persistent pattern. If anything there may be a slight cool down for Wednesday expecting cloud cover and precip to limit heating. Otherwise temps should be seasonable with lows around 60 and highs in the mid 70s to near 80 && .AVIATION...(For the 00Z TAFs through 00Z Monday Evening) Issued at 625 PM CDT SUN MAY 3 2015 There is a chance for scattered showers and storms tomorrow morning around sunrise as an outflow passes near the area. Trying to pin down the location and timing of this possible outflow is very difficult therefore did not add any mention at this point. Like the past few days the cloud bases appear to be high and will most likely not affect the flight conditions. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...65 LONG TERM...Wolters AVIATION...Sanders
AREA FORECAST DISCUSSION
NWS TOPEKA KS
406 PM CDT Sat May 2 2015 .SHORT TERM...(This Evening through Sunday) Issued at 404 PM CDT SAT MAY 2 2015 19Z water vapor imagery shows a shortwave moving across IA while 500MB profiler data suggests a more subtle wave has passed through eastern KS. Meanwhile a weak mid level ridge has propagated east and is centered over the TX big bend region with the mean westerlies remain north along the Canadian boarder. At the surface, high pressure over the southeast U.S. and low pressure in the northern plains has favored continued moisture advection with southerly winds bringing mid 50s dewpoints into the central plains. For tonight and Sunday, large scale forcing continues to be absent from the pattern. However models hint at the possibility for sporadic shower activity as early as this evening. The HRRR and RAP are the most optimistic in generating the shower activity. It appears the evening QPF is driven by warm air advection and isentropic upglide around 700MB. However RAP soundings suggest moisture will be rather limited in this layer. Because of this and the general subsidence behind the subtle wave, am not convinced showers will redevelop across central KS this evening. There are also signs that another subtle wave could come out of the CO Rockies late tonight and Sunday morning with some elevated light shower activity. There is a more organized signal in the isentropic surfaces of a shallow layer of lift Sunday morning. With bases at 10 KFT and little if any instability above this layer, am not sure any precip would amount to much and it end up being mainly virga. So have maintained a dry forecast for now, but there could be some light hit or miss precip with not much impact. Thanks for the collaboration EAX and ICT. Southerly winds and increased low level moisture should help keep lows tonight around 60 degrees. Increasing clouds from the west should also help keep overnight lows mild. With continued southerly winds, models continue the warming trend at 850MB with good mixing. Therefore have maintained highs in the lower and mid 80s. However if there is elevated shower activity, the forecast may be to warm for areas that remain cloudy. .LONG TERM...(Sunday Night through Saturday) Issued at 404 PM CDT SAT MAY 2 2015 Several opportunities for precipitation remain present through the forecast, with challenges on where and when the higher chances will be being the main challenge. The main trend in the nearer periods is the trend for a farther north settling of the cold front as it enters the area. Getting the front much past the northwest counties could be difficult with little/no additional frontogenesis from convection through Sunday afternoon along it and west to southwest flow over it. Have continued to taper precip chances, especially in the south into Monday night. There continues to be at least minor potential for severe weather and perhaps training storms near the boundary. NAM continues to look overdone with low level moisture and thus CAPE, but values near 2000 J/kg seem possible along the front with flow aloft nearly parallel to the boundary with slow cell motions and PWs near 1.5", more likely late Monday into Monday night. The front/effective front remains on track to mix back north Tuesday with some drier air moving in through the day, but attention then turns to the southwest as an upper wave remains on track to push slowly northeast through the Central Plains Tuesday night through Wednesday night. Models are fairly consistent with better upper forcing to the northwest and southeast, but also with widespread convection developing to the south-southwest and translating through late Tuesday night into Wednesday. Beyond Wednesday night, there continues to be indications of a weak boundary near to just west of the area with continued moisture availability into the area into Saturday. && .AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon) Issued at 1224 PM CDT SAT MAY 2 2015 Improving conditions will be the trend for the rest of today outside of the increase in winds. Gusts are likely as clouds dissipate and mixing takes place. Wind shear conditions could be present tomorrow morning with the LLJ increasing over the region, but did leave mention out of the TAFs for now. There is the possibility also for a round of showers or elevated convection late in the TAF period associated with a vorticity max moving out of the Central Rockies affecting all the terminals. Timing on this would be uncertain at this point but will be something to pay attention to for longer term planning. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Wolters LONG TERM...65 AVIATION...Drake
AREA FORECAST DISCUSSION
NWS GOODLAND KS
235 PM MDT SAT MAY 2 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 157 PM MDT SAT MAY 2 2015 LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW WESTERLY ZONAL FLOW IN PLACE FROM THE GREAT BASIN ACROSS THE CENTRAL ROCKIES INTO THE MISSISSIPPI VALLEY WITH EMBEDDED H5/H7 SHORTWAVE TROUGHS MOVING THROUGH THE MEAN FLOW. AT THE SURFACE LEE TROUGH HAS DEVELOPED ACROSS EASTERN COLORADO WITH A MEAN SURFACE TROUGH FROM THE NE PANHANDLE AND ALONG THE COLORADO BORDER. THUNDERSTORM ACTIVITY HAS ALREADY DEVELOPED ALONG THE CHEYENNE RIDGE AND HIGHER TERRAIN IN COLORADO. THIS AFTERNOON-TONIGHT...RAP ANALYSIS (WHICH IS IN LINE WITH EARLIER NAM) SHOWS 2000 J/KG OF SB CAPE IN PLACE ALONG AND AHEAD OF THE SURFACE TROUGH...CENTERED OVER OUR CWA. CINH APPEARS TO BE WEAKENING...HOWEVER ONLY SOME SHALLOW CU HAVE FORMED SO FAR THIS AFTERNOON. AS MID LEVEL VORTICITY ROTATES FROM THE CENTRAL ROCKIES INTO EASTERN COLORADO I WOULD EXPECT DEVELOPMENT TO SPREAD EAST WHICH IS IN LINE WITH SYNOPTIC SCALE GUIDANCE. HRRR/RAP BOTH INDICATE ISOLATED ACTIVITY DEVELOPING ALONG AND EAST OF THE SURFACE TROUGH OVER OUR CWA WITH ADDITIONAL ACTIVITY SPREADING IN FROM THE WEST. BULK SHEER/HELICITY ARE NOT VERY IMPRESSIVE AT THIS POINT WHERE BETTER INSTABILITY IS IN PLACE (WEST). MOISTURE PROFILES ARE NOT PARTICULARLY IMPRESSIVE...AND THIS COULD LIMIT COVERAGE TO ISOLATE/SCATTERED. BETTER PRECIP SIGNAL AND INSTABILITY ARE SHOW IN IN THE LOWER SHEER ENVIRONMENT...WHERE PULSE TYPE THUNDERSTORMS WOULD BE MORE LIKELY. STEEP MID LEVEL LAPSE RATES AND MODERATE INSTABILITY COULD SUPPORT STRONGER UPDRAFTS/CORES...WITH LARGE HAIL/SEVERE WINDS POSSIBLE. DCAPE VALUES 1000-1500 J/KG AND IN HIGHER TD DEPRESSIONS (MAINLY WEST) DO RAISE A CONCERN FOR INCREASED MICROBURST POTENTIAL WITH SOME OF THESE STORMS. IF ANY OF THIS ACTIVITY WAS TO MOVE INTO THE EASTERN CWA IT COULD BECOME MORE ORGANIZED WITH INCREASING SPEED SHEER (35KT BULK EFFECTIVE SHEER AROUND 00Z). AS THE SUN SETS AND WE LOOSE DAYTIME HEATING ANY LINGERING ACTIVITY SHOULD QUICKLY WEAKEN AS THERE IS ELEVATED CAPE LATE AND ONLY A WEAK LLJ IN PLACE OVERNIGHT. SUNDAY...ANOTHER VERY WARM DAY IS EXPECTED AS SURFACE TROUGH DEEPENS A LITTLE OVER THE CWA AND WAA INCREASES OVER THE CWA. THIS IS IN RESPONSE TO A STRONGER SHORTWAVE TROUGH MOVING INTO THE NORTHERN PLAINS AND A COLD FRONT DROPPING SOUTH INTO NORTHERN NEBRASKA. HIGHS SHOULD BE SIMILAR TO TODAY WITH MOST IN THE 80S...AND A FEW LOCATIONS APPROACHING 90 (MAINLY MCCOOK/HILL CITY). SURFACE TROUGH WILL SHIFT JUST A LITTLE BIT EAST AND LOW LEVEL MOISTURE RETURN COULD BRING HIGHER TD VALUES INTO NORTH CENTRAL KS. NAM MAY BE A LITTLE HIGH...BUT EITHER WAY THIS BETTER BL MOISTURE WILL SUPPORT HIGHER CAPE VALUES IN THE AFTERNOON IN THE 2000-2500 J/KG RANGE. SHEER MAY ALSO BE A LITTLE BIT BETTER WHERE GOOD INSTABILITY IS IN PLACE THAN TODAY...SO THERE MAY BE A BIGGER THREAT FOR MORE ORGANIZE THUNDERSTORM DEVELOPMENT IF ANYTHING IS TO DEVELOP IN THE AFTERNOON. THUNDERSTORM ACTIVITY IS SHOWN TO INITIATE PRIMARILY ALONG SURFACE TROUGH IN THE AFTERNOON. HOWEVER WITH DRIER MOISTURE PROFILES AGAIN IN PLACE COVERAGE COULD BE LIMITED AT LEAST UNTIL LATER WHEN BETTER LARGE SCALE FORCING/DEEPER MOISTURE MOVINGS IN TO THE REGION FROM THE NORTHWEST. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 233 PM MDT SAT MAY 2 2015 UPPER LEVEL FLOW WILL BE SOUTHWEST FROM SUNDAY NIGHT THROUGH TUESDAY AHEAD OF A LOW MOVING EAST FROM THE DESERT SOUTHWEST INTO THE CENTRAL AND SOUTHERN ROCKIES. A SURFACE TROUGH NEAR NORTHWEST KANSAS WILL MOVE EAST MONDAY. HIGH PRESSURE WILL BUILD INTO NORTHWEST KANSAS MONDAY NIGHT AND TUESDAY. AN AREA OF LOW PRESSURE WILL MOVE INTO COLORADO TUESDAY. A SHORTWAVE SHOULD AFFECT THE FA SUNDAY EVENING AND INITIATE STORMS NEAR THE SURFACE TROUGH OVER NORTHEAST COLORADO INTO SOUTHWEST NEBRASKA. PLAN TO USE HIGH CHANCE POPS IN THAT AREA WITH LOWER CHANCE POPS ELSEWHERE ACROSS THE FA. PLAN TO KEEP HIGHER CHANCE POPS ACROSS THE NORTHERN FA AS STORMS DRIFT NORTHEAST INTO THE FA OVERNIGHT. THERE SHOULD BE A LULL MONDAY MORNING BEHIND THE EXITING WAVE. POPS WILL INCREASE TO HIGH CHANCE MONDAY AFTERNOON AND EVENING AS THE NEXT SHORTWAVE COMES THROUGH. MOISTURE AND DYNAMICS LOOK GOOD FOR MONDAY NIGHT SO WILL CONTINUE HIGH CHANCE AND LIKELY POPS. GOOD DYNAMICS AND MOISTURE CONTINUE TO STREAM ACROSS THE FA TUESDAY AS THE MAIN TROUGH MOVES INTO THE AREA. PRECIPITABLE WATER VALUES ACROSS THE FA FOR TUESDAY RANGE FROM 1.0 TO 1.2 INCHES. PLAN TO CONTINUE LIKELY AND DEFINITE POPS. MIN TEMPERATURES THROUGH MONDAY NIGHT SHOULD COOL INTO THE MID 40S IN EASTERN COLORADO TO THE MID 50S IN THE EASTERN FA. MAX TEMPERATURES MONDAY SHOULD RANGE FROM THE LOWER 60S IN EASTERN COLORADO TO THE LOWER 70S IN THE EASTERN FA. IN THE EXTENDED...(TUESDAY NIGHT THROUGH SATURDAY)...AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE CENTRAL PLAINS TUESDAY NIGHT AND WEDNESDAY AND THEN LIFT OUT OF THE AREA WEDNEDAY NIGHT. GOOD DYNAMICS AND MOISTURE SUPPORT HIGH POPS THROUGH WEDNESDAY. POPS WILL DECREASE TO CHANCE THURSDAY AND FRIDAY BEHIND THE EXITING TROUGH WITH A COUPLE OF SHORTWAVES IN SOUTHWEST FLOW PRODUCING STORMS. POPS WILL INCREASE AGAIN SATURDAY AS THE NEXT UPPER LEVEL TROUGH BEGINS IMPACTING THE CENTRAL PLAINS. MIN TEMPERATURES SHOULD RANGE FROM 45 TO 55 THROUGH FRIDAY NIGHT WITH COOLER READINGS IN EASTERN COLORADO. MAX TEMPERATURES WILL GENERALLY WARM TO THE 70S EACH DAY WITH SOME UPPER 60S POSSIBLE IN EASTERN COLORADO AND NEAR 80 IN THE EASTERN FA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1137 AM MDT SAT MAY 2 2015 VFR CONDITIONS AND WINDS LESS THAN 12KT SHOULD PREVAIL AT BOTH KGLD AND KMCK TERMINALS THROUGH THE TAF PERIOD. PRIMARY AVIATION CONCERN WILL BE POTENTIAL FOR ISOLATED TO SCATTERED THUNDERSTORMS DEVELOPING ALONG SURFACE TROUGH THIS AFTERNOON AND EVENING. BETTER COVERAGE SHOULD REMAIN ALONG COLORADO STATE LINE WITH ACTIVITY TRANSITIONING EAST AND SOUTH BASED ON SHORT RANGE GUIDANCE. THIS PLACES ACTIVITY WITHIN THE VICINITY OF KGLD...BUT LIKELY SOUTH OF KMCK. POTENTIAL EXISTS FOR STRONG/SEVERE THUNDERSTORMS WITH HAIL/STRONG WINDS WITH SOME OF THESE STORMS...SO WILL NEED TO AMEND IF IT LOOKS LIKE ANY PARTICULAR STORM WILL IMPACT A TERMINAL. COVERAGE/CONFIDENCE TOO LOW TO INCLUDE MORE THAN VCTS AT KGLD AT THIS TIME. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...FS AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
157 PM MDT SAT MAY 2 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 157 PM MDT SAT MAY 2 2015 LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW WESTERLY ZONAL FLOW IN PLACE FROM THE GREAT BASIN ACROSS THE CENTRAL ROCKIES INTO THE MISSISSIPPI VALLEY WITH EMBEDDED H5/H7 SHORTWAVE TROUGHS MOVING THROUGH THE MEAN FLOW. AT THE SURFACE LEE TROUGH HAS DEVELOPED ACROSS EASTERN COLORADO WITH A MEAN SURFACE TROUGH FROM THE NE PANHANDLE AND ALONG THE COLORADO BORDER. THUNDERSTORM ACTIVITY HAS ALREADY DEVELOPED ALONG THE CHEYENNE RIDGE AND HIGHER TERRAIN IN COLORADO. THIS AFTERNOON-TONIGHT...RAP ANALYSIS (WHICH IS IN LINE WITH EARLIER NAM) SHOWS 2000 J/KG OF SB CAPE IN PLACE ALONG AND AHEAD OF THE SURFACE TROUGH...CENTERED OVER OUR CWA. CINH APPEARS TO BE WEAKENING...HOWEVER ONLY SOME SHALLOW CU HAVE FORMED SO FAR THIS AFTERNOON. AS MID LEVEL VORTICITY ROTATES FROM THE CENTRAL ROCKIES INTO EASTERN COLORADO I WOULD EXPECT DEVELOPMENT TO SPREAD EAST WHICH IS IN LINE WITH SYNOPTIC SCALE GUIDANCE. HRRR/RAP BOTH INDICATE ISOLATED ACTIVITY DEVELOPING ALONG AND EAST OF THE SURFACE TROUGH OVER OUR CWA WITH ADDITIONAL ACTIVITY SPREADING IN FROM THE WEST. BULK SHEER/HELICITY ARE NOT VERY IMPRESSIVE AT THIS POINT WHERE BETTER INSTABILITY IS IN PLACE (WEST). MOISTURE PROFILES ARE NOT PARTICULARLY IMPRESSIVE...AND THIS COULD LIMIT COVERAGE TO ISOLATE/SCATTERED. BETTER PRECIP SIGNAL AND INSTABILITY ARE SHOW IN IN THE LOWER SHEER ENVIRONMENT...WHERE PULSE TYPE THUNDERSTORMS WOULD BE MORE LIKELY. STEEP MID LEVEL LAPSE RATES AND MODERATE INSTABILITY COULD SUPPORT STRONGER UPDRAFTS/CORES...WITH LARGE HAIL/SEVERE WINDS POSSIBLE. DCAPE VALUES 1000-1500 J/KG AND IN HIGHER TD DEPRESSIONS (MAINLY WEST) DO RAISE A CONCERN FOR INCREASED MICROBURST POTENTIAL WITH SOME OF THESE STORMS. IF ANY OF THIS ACTIVITY WAS TO MOVE INTO THE EASTERN CWA IT COULD BECOME MORE ORGANIZED WITH INCREASING SPEED SHEER (35KT BULK EFFECTIVE SHEER AROUND 00Z). AS THE SUN SETS AND WE LOOSE DAYTIME HEATING ANY LINGERING ACTIVITY SHOULD QUICKLY WEAKEN AS THERE IS ELEVATED CAPE LATE AND ONLY A WEAK LLJ IN PLACE OVERNIGHT. SUNDAY...ANOTHER VERY WARM DAY IS EXPECTED AS SURFACE TROUGH DEEPENS A LITTLE OVER THE CWA AND WAA INCREASES OVER THE CWA. THIS IS IN RESPONSE TO A STRONGER SHORTWAVE TROUGH MOVING INTO THE NORTHERN PLAINS AND A COLD FRONT DROPPING SOUTH INTO NORTHERN NEBRASKA. HIGHS SHOULD BE SIMILAR TO TODAY WITH MOST IN THE 80S...AND A FEW LOCATIONS APPROACHING 90 (MAINLY MCCOOK/HILL CITY). SURFACE TROUGH WILL SHIFT JUST A LITTLE BIT EAST AND LOW LEVEL MOISTURE RETURN COULD BRING HIGHER TD VALUES INTO NORTH CENTRAL KS. NAM MAY BE A LITTLE HIGH...BUT EITHER WAY THIS BETTER BL MOISTURE WILL SUPPORT HIGHER CAPE VALUES IN THE AFTERNOON IN THE 2000-2500 J/KG RANGE. SHEER MAY ALSO BE A LITTLE BIT BETTER WHERE GOOD INSTABILITY IS IN PLACE THAN TODAY...SO THERE MAY BE A BIGGER THREAT FOR MORE ORGANIZE THUNDERSTORM DEVELOPMENT IF ANYTHING IS TO DEVELOP IN THE AFTERNOON. THUNDERSTORM ACTIVITY IS SHOWN TO INITIATE PRIMARILY ALONG SURFACE TROUGH IN THE AFTERNOON. HOWEVER WITH DRIER MOISTURE PROFILES AGAIN IN PLACE COVERAGE COULD BE LIMITED AT LEAST UNTIL LATER WHEN BETTER LARGE SCALE FORCING/DEEPER MOISTURE MOVINGS IN TO THE REGION FROM THE NORTHWEST. .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 226 AM MDT SAT MAY 2 2015 THE LONG TERM FORECAST PERIODS BEGINS WITH AN UPPER LEVEL SHORTWAVE TROUGH THAT TAKES A NEGATIVE TILT INTO THE HIGH PLAINS REGION...WHICH WILL BRING CHANCES FOR SHOWERS AND THUNDERSTORMS TUESDAY. ALTHOUGH A NEGATIVE TILT USUALLY SIGNIFIES STEEP LAPSE RATES ALOFT...IN THIS CASE THE LAPSE RATES ARE NOT TOO IMPRESSIVE WITH VERY LITTLE CAPE IN THE PROFILE. BETWEEN 200 AND 500 J/KG OF CAPE IS PRESENT ACROSS THE AREA TUESDAY AFTERNOON AND EVENING...BUT THAT IS ENOUGH WITH VERY SATURATED FORECAST SOUNDINGS TO PRODUCE EFFICIENT RAINFALL. STRONG SOUTHERLY FLOW THROUGHOUT THE ENTIRE ATMOSPHERIC PROFILE WILL ADVECT MOIST GULF AIR INTO THE REGION WITH PRECIPITABLE WATER AMOUNTS ACROSS THE AREA GREATER THAN ONE INCH...WHICH IS IN THE 99TH PERCENTILE BASED ON CLIMATOLOGY. THEREFORE...INCREASED POP AND QPF VALUES IN THE FORECAST FOR THIS PERIOD WITH THE EXPECTATION OF WIDESPREAD MODERATE RAINFALL...WITH LOCALLY HEAVY AMOUNTS. IN THE EARLY MORNING HOURS WEDNESDAY...GFS SOUNDINGS INDICATE AN INTRUSION OF DRY MID LEVEL AIR...WHICH WILL INCREASE CAPE VALUES IN THE PROFILE HEADING INTO WEDNESDAY AFTERNOON BETWEEN 1000 AND 1800 J/KG....WHICH COULD RESULT IN SOME STRONGER THUNDERSTORMS. SEVERE POTENTIAL DOES NOT LOOK STRONG AT THIS POINT WITH WEAK SURFACE FORCING...MARGINAL SPEED AND DIRECTIONAL SHEAR...AND DISAGREEMENT IN MODEL FORECASTS REGARDING JET POSITION. ALTHOUGH MODELS DISAGREE SLIGHTLY TO THE UPPER LEVEL TROUGH POSITION...TIMING AND PATTERN GENERALLY LINE UP ON THURSDAY AFTERNOON WITH THE UPPER TROUGH GETTING PINCHED OFF FROM THE MAIN FLOW AND BECOMING CUT OFF OVER THE WESTERN THIRD OF THE CONUS. BECAUSE THE LOW WILL BECOME REMOVED FROM THE MAIN UPPER JET FLOW...THE FEATURE WILL SPIN SLOWLY EASTWARD OVER THE HIGH PLAINS REGION PROVIDING CHANCES FOR SHOWERS AND THUNDERSTORMS THURSDAY NIGHT THROUGH FRIDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1137 AM MDT SAT MAY 2 2015 VFR CONDITIONS AND WINDS LESS THAN 12KT SHOULD PREVAIL AT BOTH KGLD AND KMCK TERMINALS THROUGH THE TAF PERIOD. PRIMARY AVIATION CONCERN WILL BE POTENTIAL FOR ISOLATED TO SCATTERED THUNDERSTORMS DEVELOPING ALONG SURFACE TROUGH THIS AFTERNOON AND EVENING. BETTER COVERAGE SHOULD REMAIN ALONG COLORADO STATE LINE WITH ACTIVITY TRANSITIONING EAST AND SOUTH BASED ON SHORT RANGE GUIDANCE. THIS PLACES ACTIVITY WITHIN THE VICINITY OF KGLD...BUT LIKELY SOUTH OF KMCK. POTENTIAL EXISTS FOR STRONG/SEVERE THUNDERSTORMS WITH HAIL/STRONG WINDS WITH SOME OF THESE STORMS...SO WILL NEED TO AMEND IF IT LOOKS LIKE ANY PARTICULAR STORM WILL IMPACT A TERMINAL. COVERAGE/CONFIDENCE TOO LOW TO INCLUDE MORE THAN VCTS AT KGLD AT THIS TIME. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...MK AVIATION...DR
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1244 PM CDT Sat May 2 2015 .UPDATE... Issued at 911 AM CDT SAT MAY 2 2015 Updated the forecast to keep a mention of scattered showers over eastern KS into the early afternoon. The RAP has analyzed a weak vort max drifting over the area which can be seen in the 500MB profiler data. Think the HRRR may have a reasonable grasp on the showers through the morning. Also there appears to be little or no instability. Mid level lapse rates are not that steep and models prog little change to them into the early afternoon. With there being little lightning activity now, do not think it will intensify over the next several hours so have removed the mention of thunder from the forecast. UPDATE Issued at 649 AM CDT SAT MAY 2 2015 More light showers are developing across central and south central KS this morning and have upped POPs for southern portions of forecast area this morning because of that. Precip falling from mid-level deck and considerable low-level dry air to overcome, so expect sprinkles to a few hundredths at most with this activity. Short range models weaken this area this morning as it moves east. Otherwise no changes to going forecast. && ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 351 AM CDT SAT MAY 2 2015 Showers/isolated thunderstorms across southeast Nebraska and far northeast KS are occurring in elevated warm advection zone near convergence at nose of low-level jet. This activity has been confined to far northeastern part of forecast area and should remain there this morning. Bigger question what else gets going in central/north central KS in the next few hours and that could move across a far greater portion of northeast KS this morning. Poorly defined shortwave trough seen best in RAP analysis and also somewhat apparent in water vapor loop moving toward north central KS at the current time. HRRR, RAP and 06Z NAM all have a larger area of precip developing in the next few hours apparently associated with this feature. If it develops as forecast, it will affect a wider part of northeast KS this morning than previously thought. Have expanded area of 20-30 percent POPs this morning due to trends in short range models, but difficult to go too high with virtually nothing showing up on radar over central KS at this time. Whatever precip develops should be moving out of far northeast KS early this afternoon and expect dry conditions for the rest of this afternoon through tonight as weak ridging aloft is over the area. Temps today will depend on cloud cover with far eastern KS most likely to see the most persistent clouds and temps only in the upper 70s while some clearing this afternoon in central KS should lead to lower 80s. .LONG TERM...(Sunday through Friday) Issued at 351 AM CDT SAT MAY 2 2015 By Sunday, models show a broad mid-level ridge stretched across the southern CONUS with surface low pressure extending from the High Plains into the Northern Plains. With this low pressure just west of the forecast area, a decent pressure gradient is expected to set up over the area, resulting in breezy southerly winds supporting good warm-air advection across the entire forecast area. With these conditions in place, have continued to trend on the warmer side of model guidance with highs in the low/mid 80s. Models continue to hold off on the front moving into north central Kansas until Sunday evening, so have a dry forecast for the daytime hours with chance to likely PoPs Sunday night through Monday as the cold front advances into the CWA and then stalls out over the area. By Monday the mid-level ridge will be focused across the southeastern U.S. and should start building northward Monday night into Tuesday, causing the stalled cold front to lift northward as a warm front. There are still some model discrepancies with how far north the warm front will lift (near the KS/NE border or into southern NE), but have lowered or even removed PoPs from far east central Kansas Monday night with likely PoPs still near the KS/NE border. The best chance for dry conditions looks to be on Tuesday with the front likely to the north, so have continued to drop PoPs to only slight chances or even dry for some locations. However, shower and thunderstorm chances return Tuesday night as a mid-level trough over the southwestern U.S. lifts northeastward toward the area, strengthening the surface low pressure system and pushing it into the High Plains. Models seem to be coming into slightly better agreement with the tracking of the mid-level trough and surface low, with the trough lifting into the Central Plains Wed/Wed night and into the Northern Plains by Thursday. At the surface, the surface low and associated cold front look to be stalled out along the High Plains Tuesday night through Wednesday before shifting a bit further east. With this steady southerly flow into the region, should see some modest moisture advection into the area by mid- week as we should be able to tap into moisture from the Gulf of Mexico. This moisture advection along with some mid-level forcing will bring increasing chances for scattered showers and thunderstorms Tuesday night through Wednesday night with diminishing chances for the remainder of the week as we lose the mid-level forcing. With low confidence in whether or not scattered precipitation will be lingering by the end of the week, have dropped PoPs to low-end chances for Thursday night and Friday. The persistent southerly flow and moisture advection also will lead to mild conditions with highs in the 70s and lows in the 50s/60s as well as humid conditions with dewpoints steadily in the 50s/60s. && .AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon) Issued at 1224 PM CDT SAT MAY 2 2015 Improving conditions will be the trend for the rest of today outside of the increase in winds. Gusts are likely as clouds dissipate and mixing takes place. Wind shear conditions could be present tomorrow morning with the LLJ increasing over the region, but did leave mention out of the TAFs for now. There is the possibility also for a round of showers or elevated convection late in the TAF period associated with a vorticity max moving out of the Central Rockies affecting all the terminals. Timing on this would be uncertain at this point but will be something to pay attention to for longer term planning. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Wolters SHORT TERM...GDP LONG TERM...Hennecke AVIATION...Drake
AREA FORECAST DISCUSSION
NWS TOPEKA KS
911 AM CDT Sat May 2 2015 .UPDATE... Issued at 911 AM CDT SAT MAY 2 2015 Updated the forecast to keep a mention of scattered showers over eastern KS into the early afternoon. The RAP has analyzed a weak vort max drifting over the area which can be seen in the 500MB profiler data. Think the HRRR may have a reasonable grasp on the showers through the morning. Also there appears to be little or no instability. Mid level lapse rates are not that steep and models prog little change to them into the early afternoon. With there being little lightning activity now, do not think it will intensify over the next several hours so have removed the mention of thunder from the forecast. UPDATE Issued at 649 AM CDT SAT MAY 2 2015 More light showers are developing across central and south central KS this morning and have upped POPs for southern portions of forecast area this morning because of that. Precip falling from mid-level deck and considerable low-level dry air to overcome, so expect sprinkles to a few hundredths at most with this activity. Short range models weaken this area this morning as it moves east. Otherwise no changes to going forecast. && .SHORT TERM...(Today and Tonight) Issued at 351 AM CDT SAT MAY 2 2015 Showers/isolated thunderstorms across southeast Nebraska and far northeast KS are occurring in elevated warm advection zone near convergence at nose of low-level jet. This activity has been confined to far northeastern part of forecast area and should remain there this morning. Bigger question what else gets going in central/north central KS in the next few hours and that could move across a far greater portion of northeast KS this morning. Poorly defined shortwave trough seen best in RAP analysis and also somewhat apparent in water vapor loop moving toward north central KS at the current time. HRRR, RAP and 06Z NAM all have a larger area of precip developing in the next few hours apparently associated with this feature. If it develops as forecast, it will affect a wider part of northeast KS this morning than previously thought. Have expanded area of 20-30 percent POPs this morning due to trends in short range models, but difficult to go too high with virtually nothing showing up on radar over central KS at this time. Whatever precip develops should be moving out of far northeast KS early this afternoon and expect dry conditions for the rest of this afternoon through tonight as weak ridging aloft is over the area. Temps today will depend on cloud cover with far eastern KS most likely to see the most persistent clouds and temps only in the upper 70s while some clearing this afternoon in central KS should lead to lower 80s. .LONG TERM...(Sunday through Friday) Issued at 351 AM CDT SAT MAY 2 2015 By Sunday, models show a broad mid-level ridge stretched across the southern CONUS with surface low pressure extending from the High Plains into the Northern Plains. With this low pressure just west of the forecast area, a decent pressure gradient is expected to set up over the area, resulting in breezy southerly winds supporting good warm-air advection across the entire forecast area. With these conditions in place, have continued to trend on the warmer side of model guidance with highs in the low/mid 80s. Models continue to hold off on the front moving into north central Kansas until Sunday evening, so have a dry forecast for the daytime hours with chance to likely PoPs Sunday night through Monday as the cold front advances into the CWA and then stalls out over the area. By Monday the mid-level ridge will be focused across the southeastern U.S. and should start building northward Monday night into Tuesday, causing the stalled cold front to lift northward as a warm front. There are still some model discrepancies with how far north the warm front will lift (near the KS/NE border or into southern NE), but have lowered or even removed PoPs from far east central Kansas Monday night with likely PoPs still near the KS/NE border. The best chance for dry conditions looks to be on Tuesday with the front likely to the north, so have continued to drop PoPs to only slight chances or even dry for some locations. However, shower and thunderstorm chances return Tuesday night as a mid-level trough over the southwestern U.S. lifts northeastward toward the area, strengthening the surface low pressure system and pushing it into the High Plains. Models seem to be coming into slightly better agreement with the tracking of the mid-level trough and surface low, with the trough lifting into the Central Plains Wed/Wed night and into the Northern Plains by Thursday. At the surface, the surface low and associated cold front look to be stalled out along the High Plains Tuesday night through Wednesday before shifting a bit further east. With this steady southerly flow into the region, should see some modest moisture advection into the area by mid- week as we should be able to tap into moisture from the Gulf of Mexico. This moisture advection along with some mid-level forcing will bring increasing chances for scattered showers and thunderstorms Tuesday night through Wednesday night with diminishing chances for the remainder of the week as we lose the mid-level forcing. With low confidence in whether or not scattered precipitation will be lingering by the end of the week, have dropped PoPs to low-end chances for Thursday night and Friday. The persistent southerly flow and moisture advection also will lead to mild conditions with highs in the 70s and lows in the 50s/60s as well as humid conditions with dewpoints steadily in the 50s/60s. && .AVIATION...(For the 12Z TAFs through 12Z Sunday Morning) Issued at 649 AM CDT SAT MAY 2 2015 Considerable mid-level cloudiness expected for much of the day time hours. Light showers may affect MHK, TOP and FOE this morning but may be nothing more than sprinkles. Fewer clouds expected by late afternoon. VFR through the period. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Wolters SHORT TERM...GDP LONG TERM...Hennecke AVIATION...GDP
AREA FORECAST DISCUSSION
NWS TOPEKA KS
656 AM CDT Sat May 2 2015 ...Update to short term and aviation forecast discussion... .UPDATE... Issued at 649 AM CDT SAT MAY 2 2015 More light showers are developing across central and south central KS this morning and have upped POPs for southern portions of forecast area this morning because of that. Precip falling from mid-level deck and considerable low-level dry air to overcome, so expect sprinkles to a few hundredths at most with this activity. Short range models weaken this area this morning as it moves east. Otherwise no changes to going forecast. && .SHORT TERM...(Today and Tonight) Issued at 351 AM CDT SAT MAY 2 2015 Showers/isolated thunderstorms across southeast Nebraska and far northeast KS are occurring in elevated warm advection zone near convergence at nose of low-level jet. This activity has been confined to far northeastern part of forecast area and should remain there this morning. Bigger question what else gets going in central/north central KS in the next few hours and that could move across a far greater portion of northeast KS this morning. Poorly defined shortwave trough seen best in RAP analysis and also somewhat apparent in water vapor loop moving toward north central KS at the current time. HRRR, RAP and 06Z NAM all have a larger area of precip developing in the next few hours apparently associated with this feature. If it develops as forecast, it will affect a wider part of northeast KS this morning than previously thought. Have expanded area of 20-30 percent POPs this morning due to trends in short range models, but difficult to go too high with virtually nothing showing up on radar over central KS at this time. Whatever precip develops should be moving out of far northeast KS early this afternoon and expect dry conditions for the rest of this afternoon through tonight as weak ridging aloft is over the area. Temps today will depend on cloud cover with far eastern KS most likely to see the most persistent clouds and temps only in the upper 70s while some clearing this afternoon in central KS should lead to lower 80s. .LONG TERM...(Sunday through Friday) Issued at 351 AM CDT SAT MAY 2 2015 By Sunday, models show a broad mid-level ridge stretched across the southern conus with surface low pressure extending from the High Plains into the Northern Plains. With this low pressure just west of the forecast area, a decent pressure gradient is expected to set up over the area, resulting in breezy southerly winds supporting good warm-air advection across the entire forecast area. With these conditions in place, have continued to trend on the warmer side of model guidance with highs in the low/mid 80s. Models continue to hold off on the front moving into north central Kansas until Sunday evening, so have a dry forecast for the daytime hours with chance to likely PoPs Sunday night through Monday as the cold front advances into the CWA and then stalls out over the area. By Monday the mid-level ridge will be focused across the southeastern U.S. and should start building northward Monday night into Tuesday, causing the stalled cold front to lift northward as a warm front. There are still some model discrepancies with how far north the warm front will lift (near the KS/NE border or into southern NE), but have lowered or even removed PoPs from far east central Kansas Monday night with likely PoPs still near the KS/NE border. The best chance for dry conditions looks to be on Tuesday with the front likely to the north, so have continued to drop PoPs to only slight chances or even dry for some locations. However, shower and thunderstorm chances return Tuesday night as a mid-level trough over the southwestern U.S. lifts northeastward toward the area, strengthening the surface low pressure system and pushing it into the High Plains. Models seem to be coming into slightly better agreement with the tracking of the mid-level trough and surface low, with the trough lifting into the Central Plains Wed/Wed night and into the Northern Plains by Thursday. At the surface, the surface low and associated cold front look to be stalled out along the High Plains Tuesday night through Wednesday before shifting a bit further east. With this steady southerly flow into the region, should see some modest moisture advection into the area by mid- week as we should be able to tap into moisture from the Gulf of Mexico. This moisture advection along with some mid-level forcing will bring increasing chances for scattered showers and thunderstorms Tuesday night through Wednesday night with diminishing chances for the remainder of the week as we lose the mid-level forcing. With low confidence in whether or not scattered precipitation will be lingering by the end of the week, have dropped PoPs to low-end chances for Thursday night and Friday. The persistent southerly flow and moisture advection also will lead to mild conditions with highs in the 70s and lows in the 50s/60s as well as humid conditions with dewpoints steadily in the 50s/60s. && .AVIATION...(For the 12Z TAFs through 12Z Sunday Morning) Issued at 649 AM CDT SAT MAY 2 2015 Considerable mid-level cloudiness expected for much of the day time hours. Light showers may affect MHK, TOP and FOE this morning but may be nothing more than sprinkles. Fewer clouds expected by late afternoon. VFR through the period. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GDP SHORT TERM...GDP LONG TERM...Hennecke AVIATION...GDP
AREA FORECAST DISCUSSION
NWS TOPEKA KS
353 AM CDT Sat May 2 2015 .SHORT TERM...(Today and Tonight) Issued at 351 AM CDT SAT MAY 2 2015 Showers/isolated thunderstorms across southeast Nebraska and far northeast KS are occurring in elevated warm advection zone near convergence at nose of low-level jet. This activity has been confined to far northeastern part of forecast area and should remain there this morning. Bigger question what else gets going in central/north central KS in the next few hours and that could move across a far greater portion of northeast KS this morning. Poorly defined shortwave trough seen best in RAP analysis and also somewhat apparent in water vapor loop moving toward north central KS at the current time. HRRR, RAP and 06Z NAM all have a larger area of precip developing in the next few hours apparently associated with this feature. If it develops as forecast, it will affect a wider part of northeast KS this morning than previously thought. Have expanded area of 20-30 percent POPs this morning due to trends in short range models, but difficult to go too high with virtually nothing showing up on radar over central KS at this time. Whatever precip develops should be moving out of far northeast KS early this afternoon and expect dry conditions for the rest of this afternoon through tonight as weak ridging aloft is over the area. Temps today will depend on cloud cover with far eastern KS most likely to see the most persistent clouds and temps only in the upper 70s while some clearing this afternoon in central KS should lead to lower 80s. .LONG TERM...(Sunday through Friday) Issued at 351 AM CDT SAT MAY 2 2015 By Sunday, models show a broad mid-level ridge stretched across the southern conus with surface low pressure extending from the High Plains into the Northern Plains. With this low pressure just west of the forecast area, a decent pressure gradient is expected to set up over the area, resulting in breezy southerly winds supporting good warm-air advection across the entire forecast area. With these conditions in place, have continued to trend on the warmer side of model guidance with highs in the low/mid 80s. Models continue to hold off on the front moving into north central Kansas until Sunday evening, so have a dry forecast for the daytime hours with chance to likely PoPs Sunday night through Monday as the cold front advances into the CWA and then stalls out over the area. By Monday the mid-level ridge will be focused across the southeastern U.S. and should start building northward Monday night into Tuesday, causing the stalled cold front to lift northward as a warm front. There are still some model discrepancies with how far north the warm front will lift (near the KS/NE border or into southern NE), but have lowered or even removed PoPs from far east central Kansas Monday night with likely PoPs still near the KS/NE border. The best chance for dry conditions looks to be on Tuesday with the front likely to the north, so have continued to drop PoPs to only slight chances or even dry for some locations. However, shower and thunderstorm chances return Tuesday night as a mid-level trough over the southwestern U.S. lifts northeastward toward the area, strengthening the surface low pressure system and pushing it into the High Plains. Models seem to be coming into slightly better agreement with the tracking of the mid-level trough and surface low, with the trough lifting into the Central Plains Wed/Wed night and into the Northern Plains by Thursday. At the surface, the surface low and associated cold front look to be stalled out along the High Plains Tuesday night through Wednesday before shifting a bit further east. With this steady southerly flow into the region, should see some modest moisture advection into the area by mid- week as we should be able to tap into moisture from the Gulf of Mexico. This moisture advection along with some mid-level forcing will bring increasing chances for scattered showers and thunderstorms Tuesday night through Wednesday night with diminishing chances for the remainder of the week as we lose the mid-level forcing. With low confidence in whether or not scattered precipitation will be lingering by the end of the week, have dropped PoPs to low-end chances for Thursday night and Friday. The persistent southerly flow and moisture advection also will lead to mild conditions with highs in the 70s and lows in the 50s/60s as well as humid conditions with dewpoints steadily in the 50s/60s. && .AVIATION...(For the 06Z TAFs through 06Z Saturday Night) Issued at 1128 PM CDT FRI MAY 1 2015 VFR conditions expected through most of the taf period. Low level wind shear was not well forecasted by the models therefore have added a group based on current observations. The models are also hinting at a shortwave tracking across the area during mid day. An isolated shower or storm could be possible with this feature although confidence was too low at this point to mention. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GDP LONG TERM...Hennecke AVIATION...Sanders
AREA FORECAST DISCUSSION
NWS GOODLAND KS
228 AM MDT SAT MAY 2 2015 .UPDATE... ISSUED AT 540 PM MDT FRI MAY 1 2015 UPDATE TO GOING FORECAST TO ACCOUNT FOR VEIL OF MID/HIGH CLOUDS CURRENTLY OVER THE AREA. ALL ACTIVITY EMANATING FROM CONVECTION OFF OVER CENTRAL COLORADO. TREND IS TO CONTINUE EASTWARD THRU THE EVENING HOURS BEFORE DECREASING AFTER MIDNIGHT. HAVE GONE WITH CLOUDY BECOMING PARTLY CLOUDY LATE FOR THE CWA. REST OF FORECAST IS ON TRACK AT THIS TIME. CONVECTION OVER CENTRAL COLORADO IS FINALLY EDGING INTO PORTIONS OF EASTERN COLORADO...SO WILL LEAVE CURRENT POPS FOR TRW/RW IN PLACE. && .SHORT TERM...(THIS AFTERNOON THROUGH SATURDAY) ISSUED AT 150 PM MDT FRI MAY 1 2015 EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS BROAD RIDGE IN PLACE ACROSS THE SOUTHERN PLAINS WITH WESTERLY FLOW EXTENDING FROM THE GREAT BASIN ACROSS THE CENTRAL ROCKIES AND INTO THE CENTRAL PLAINS. A WEAK SHORTWAVE H5/H7 TROUGH IS IN THE PROCESS OF ROTATING THROUGH THE MEAN FLOW ACROSS THE CENTRAL ROCKIES WITH SHOWER/THUNDERSTORM DEVELOPMENT APPARENT ON UPSTREAM RADARS MOVING EAST OFF THE HIGHER TERRAIN. AT THE SURFACE LOW PRESSURE IS IN PLACE ACROSS THE CWA WITH A STATIONARY FRONT ALONG THE SOUTHEASTERN CORNER OF THE CWA EXTENDING SOUTH IN SOUTHEAST COLORADO. THIS AFTERNOON-TONIGHT...FOCUS CONTINUES TO BE ON POTENTIAL FOR THUNDERSTORMS DEVELOPING OVER THE CWA OR SPREADING EAST INTO THE CWA AS SHORTWAVE MOVES THROUGH THE REGION. WITH FRONT IN PLACE AND AIR MASS DESTABILIZING THERE IS SOME CONCERN THAT ISOLATED THUNDERSTORMS COULD DEVELOP AHEAD OF MAIN SHORTWAVE. HIGH CINH VALUES CURRENTLY IN PLACE ARE INHIBITING CONVECTION CURRENTLY OVER THE CWA DESPITE INCREASING INSTABILITY. AS SHORTWAVE MOVES EAST IT APPEARS THE CAP SHOULD WEAKEN ALLOWING FOR INCREASING CHANCES FROM THE WEST TO THE EAST. BEST PRECIP SIGNAL FROM RAP/HRRR CONTINUES TO BE IN THE SOUTHWEST PART OF THE CWA. 12Z GUIDANCE WAS RUNNING HIGH REGARDING CAPE VALUES MOST OF THE DAY...THOUGH AS SKIES HAVE CLEARED THE LATEST RAP ANALYSIS DOES SHOW 500-1000 KG/J ML CAPE DEVELOPING OVER THE REGION. SHEER IS NOT PARTICULARLY IMPRESSIVE AND AT THIS POINT SEVERE THREAT SEEMS TO BE LIMITED. ANY SHOWER/THUNDERSTORM ACTIVITY SHOULD QUICKLY DISSIPATE OR TRANSITION EAST OF THE CWA THROUGH LATE THIS EVENING AS A SHARP AREA OF SUBSIDENCE MOVES IN BEHIND EXITING SHORTWAVE. SATURDAY...VERY GOOD WAA IS ADVERTISED AND WITH CLEARING SKIES DURING THE FIRST PART OF THE DAY HIGHS SHOULD REACH THE 80S ACROSS THE CWA...POSSIBLY IN THE MID/UPPER 80S IN THE EAST. THE NEXT SHORTWAVE IS SHOWN TO APPROACH THE REGION FROM THE CENTRAL ROCKIES LATE AFTERNOON WITH THUNDERSTORM INITIATION NEAR SURFACE TROUGH ALONG CO/KS BORDER POSSIBLE AFTER 21Z...OTHERWISE BETTER CHANCES ARRIVE LATER IN THE EVENING. MODELS ARE SHOWING VERY UNSTABLE AIR BUILDING OVER THE REGION WITH NAM ADVERTISING 1500-2500 J/KG OF ML CAPE BY LATE AFTERNOON. SHEER IS A LITTLE BETTER THAN TODAY WITH EFFECTIVE SHEER IN EXCESS OF 35KT. WITH THIS IN MIND ANY THUNDERSTORMS THAT DEVELOP LATE TUESDAY AFTERNOON COULD POTENTIALLY ORGANIZE AND BECOME SEVERE. WITH MINIMAL LOW LEVEL SHEER LARGE HAIL/DAMAGING WIND CONTINUE TO BE MAIN CONCERNS. .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 226 AM MDT SAT MAY 2 2015 THE LONG TERM FORECAST PERIODS BEGINS WITH AN UPPER LEVEL SHORTWAVE TROUGH THAT TAKES A NEGATIVE TILT INTO THE HIGH PLAINS REGION...WHICH WILL BRING CHANCES FOR SHOWERS AND THUNDERSTORMS TUESDAY. ALTHOUGH A NEGATIVE TILT USUALLY SIGNIFIES STEEP LAPSE RATES ALOFT...IN THIS CASE THE LAPSE RATES ARE NOT TOO IMPRESSIVE WITH VERY LITTLE CAPE IN THE PROFILE. BETWEEN 200 AND 500 J/KG OF CAPE IS PRESENT ACROSS THE AREA TUESDAY AFTERNOON AND EVENING...BUT THAT IS ENOUGH WITH VERY SATURATED FORECAST SOUNDINGS TO PRODUCE EFFICIENT RAINFALL. STRONG SOUTHERLY FLOW THROUGHOUT THE ENTIRE ATMOSPHERIC PROFILE WILL ADVECT MOIST GULF AIR INTO THE REGION WITH PRECIPITABLE WATER AMOUNTS ACROSS THE AREA GREATER THAN ONE INCH...WHICH IS IN THE 99TH PERCENTILE BASED ON CLIMATOLOGY. THEREFORE...INCREASED POP AND QPF VALUES IN THE FORECAST FOR THIS PERIOD WITH THE EXPECTATION OF WIDESPREAD MODERATE RAINFALL...WITH LOCALLY HEAVY AMOUNTS. IN THE EARLY MORNING HOURS WEDNESDAY...GFS SOUNDINGS INDICATE AN INTRUSION OF DRY MID LEVEL AIR...WHICH WILL INCREASE CAPE VALUES IN THE PROFILE HEADING INTO WEDNESDAY AFTERNOON BETWEEN 1000 AND 1800 J/KG....WHICH COULD RESULT IN SOME STRONGER THUNDERSTORMS. SEVERE POTENTIAL DOES NOT LOOK STRONG AT THIS POINT WITH WEAK SURFACE FORCING...MARGINAL SPEED AND DIRECTIONAL SHEAR...AND DISAGREEMENT IN MODEL FORECASTS REGARDING JET POSITION. ALTHOUGH MODELS DISAGREE SLIGHTLY TO THE UPPER LEVEL TROUGH POSITION...TIMING AND PATTERN GENERALLY LINE UP ON THURSDAY AFTERNOON WITH THE UPPER TROUGH GETTING PINCHED OFF FROM THE MAIN FLOW AND BECOMING CUT OFF OVER THE WESTERN THIRD OF THE CONUS. BECAUSE THE LOW WILL BECOME REMOVED FROM THE MAIN UPPER JET FLOW...THE FEATURE WILL SPIN SLOWLY EASTWARD OVER THE HIGH PLAINS REGION PROVIDING CHANCES FOR SHOWERS AND THUNDERSTORMS THURSDAY NIGHT THROUGH FRIDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1115 PM MDT FRI MAY 1 2015 KGLD...VFR THROUGH THE PERIOD. SOUTHWEST WINDS 5-10KTS AT TAF ISSUANCE EXPECTED TO BACK TO THE SOUTH AT SIMILAR SPEEDS AROUND 19Z THEN SOUTHWEST NEAR 10KTS FROM 02Z THROUGH THE REST OF THE TAF PERIOD. THUNDERSTORMS ARE POSSIBLE AROUND OR OVER THE TERMINAL AFTER 02Z THUS VCTS WORDING. KMCK...VFR THROUGH THE PERIOD. LIGHT SOUTHWEST WIND AT TAF ISSUANCE EXPECTED THROUGH THE TAF PERIOD. MAY SEE A FEW SHOWERS FROM TAF ISSUANCE THROUGH 07Z AND VARIABLE WINDS GUSTING 20KTS OR SO POSSIBLE. OTHERWISE...NO PRECIPITATION EXPECTED. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JN SHORT TERM...DR LONG TERM...MK AVIATION...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1115 PM MDT FRI MAY 1 2015 .UPDATE... ISSUED AT 540 PM MDT FRI MAY 1 2015 UPDATE TO GOING FORECAST TO ACCOUNT FOR VEIL OF MID/HIGH CLOUDS CURRENTLY OVER THE AREA. ALL ACTIVITY EMANATING FROM CONVECTION OFF OVER CENTRAL COLORADO. TREND IS TO CONTINUE EASTWARD THRU THE EVENING HOURS BEFORE DECREASING AFTER MIDNIGHT. HAVE GONE WITH CLOUDY BECOMING PARTLY CLOUDY LATE FOR THE CWA. REST OF FORECAST IS ON TRACK AT THIS TIME. CONVECTION OVER CENTRAL COLORADO IS FINALLY EDGING INTO PORTIONS OF EASTERN COLORADO...SO WILL LEAVE CURRENT POPS FOR TRW/RW IN PLACE. && .SHORT TERM...(THIS AFTERNOON THROUGH SATURDAY) ISSUED AT 150 PM MDT FRI MAY 1 2015 EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS BROAD RIDGE IN PLACE ACROSS THE SOUTHERN PLAINS WITH WESTERLY FLOW EXTENDING FROM THE GREAT BASIN ACROSS THE CENTRAL ROCKIES AND INTO THE CENTRAL PLAINS. A WEAK SHORTWAVE H5/H7 TROUGH IS IN THE PROCESS OF ROTATING THROUGH THE MEAN FLOW ACROSS THE CENTRAL ROCKIES WITH SHOWER/THUNDERSTORM DEVELOPMENT APPARENT ON UPSTREAM RADARS MOVING EAST OFF THE HIGHER TERRAIN. AT THE SURFACE LOW PRESSURE IS IN PLACE ACROSS THE CWA WITH A STATIONARY FRONT ALONG THE SOUTHEASTERN CORNER OF THE CWA EXTENDING SOUTH IN SOUTHEAST COLORADO. THIS AFTERNOON-TONIGHT...FOCUS CONTINUES TO BE ON POTENTIAL FOR THUNDERSTORMS DEVELOPING OVER THE CWA OR SPREADING EAST INTO THE CWA AS SHORTWAVE MOVES THROUGH THE REGION. WITH FRONT IN PLACE AND AIR MASS DESTABILIZING THERE IS SOME CONCERN THAT ISOLATED THUNDERSTORMS COULD DEVELOP AHEAD OF MAIN SHORTWAVE. HIGH CINH VALUES CURRENTLY IN PLACE ARE INHIBITING CONVECTION CURRENTLY OVER THE CWA DESPITE INCREASING INSTABILITY. AS SHORTWAVE MOVES EAST IT APPEARS THE CAP SHOULD WEAKEN ALLOWING FOR INCREASING CHANCES FROM THE WEST TO THE EAST. BEST PRECIP SIGNAL FROM RAP/HRRR CONTINUES TO BE IN THE SOUTHWEST PART OF THE CWA. 12Z GUIDANCE WAS RUNNING HIGH REGARDING CAPE VALUES MOST OF THE DAY...THOUGH AS SKIES HAVE CLEARED THE LATEST RAP ANALYSIS DOES SHOW 500-1000 KG/J ML CAPE DEVELOPING OVER THE REGION. SHEER IS NOT PARTICULARLY IMPRESSIVE AND AT THIS POINT SEVERE THREAT SEEMS TO BE LIMITED. ANY SHOWER/THUNDERSTORM ACTIVITY SHOULD QUICKLY DISSIPATE OR TRANSITION EAST OF THE CWA THROUGH LATE THIS EVENING AS A SHARP AREA OF SUBSIDENCE MOVES IN BEHIND EXITING SHORTWAVE. SATURDAY...VERY GOOD WAA IS ADVERTISED AND WITH CLEARING SKIES DURING THE FIRST PART OF THE DAY HIGHS SHOULD REACH THE 80S ACROSS THE CWA...POSSIBLY IN THE MID/UPPER 80S IN THE EAST. THE NEXT SHORTWAVE IS SHOWN TO APPROACH THE REGION FROM THE CENTRAL ROCKIES LATE AFTERNOON WITH THUNDERSTORM INITIATION NEAR SURFACE TROUGH ALONG CO/KS BORDER POSSIBLE AFTER 21Z...OTHERWISE BETTER CHANCES ARRIVE LATER IN THE EVENING. MODELS ARE SHOWING VERY UNSTABLE AIR BUILDING OVER THE REGION WITH NAM ADVERTISING 1500-2500 J/KG OF ML CAPE BY LATE AFTERNOON. SHEER IS A LITTLE BETTER THAN TODAY WITH EFFECTIVE SHEER IN EXCESS OF 35KT. WITH THIS IN MIND ANY THUNDERSTORMS THAT DEVELOP LATE TUESDAY AFTERNOON COULD POTENTIALLY ORGANIZE AND BECOME SEVERE. WITH MINIMAL LOW LEVEL SHEER LARGE HAIL/DAMAGING WIND CONTINUE TO BE MAIN CONCERNS. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 218 PM MDT FRI MAY 1 2015 A FLATTENED RIDGE WILL BE OVER THE SOUTHERN PLAINS THROUGH SUNDAY NIGHT WITH WESTERLY FLOW OVER THE CENTRAL PLAINS. THE SOUTHERN PLAINS RIDGE WILL SHIFT EASTWARD MONDAY WITH SOUTHWEST FLOW OVER THE CENTRAL PLAINS. A SURFACE TROUGH OVER EASTERN COLORADO WILL MIGRATE SLOWLY EAST ACROSS NORTHWEST KANSAS THROUGH SUNDAY NIGHT. SURFACE HIGH PRESSURE WILL MOVE INTO THE REGION MONDAY BEHIND THE EXITING TROUGH. A SHORTWAVE MOVES ACROSS THE FA SATURDAY EVENING WITH SUBSIDENCE INDICATED AFTER 06Z TUESDAY AS THE SHORTWAVE SLIDES SOUTHEAST OUT OF THE AREA. H8-7 LAYER MEAN RH IS NOT IDEAL SO WILL KEEP POPS AT SLIGHT CHANCE. CAPE VALUES UP TO 1000 J/KG ARE EXPECTED WITH AN AREA OF 35 KTS SHEAR OVER NORTHEAST COLORADO. A FEW ISOLATED MARGINALLY SEVERE STORMS ARE POSSIBLE. SUBSIDENCE CONTINUES THROUGH SUNDAY MORNING AND INTO THE AFTERNOON. THE NEXT SHORTWAVE SHOULD IMPACT EASTERN COLORADO BY MID TO LATE AFTERNOON. PLAN TO GO WITH CHANCE POPS OVER WESTERN PORTIONS OF EASTERN COLORADO AND ALSO NEAR THE TROUGH AXIS IN THE SOUTHEASTERN FA. GOOD DYNAMICS AND MOISTURE MOVE ACROSS THE FA SUNDAY NIGHT SO WILL GO WITH HIGHER CHANCE POPS ESPECIALLY IN THE WEST DURING THE EVENING WHERE STORMS SHOULD ALREADY BE IN PROGRESS. HIGH CHANCE POPS WILL CONTINUE AFTER 06Z MONDAY AS THE SHORTWAVE IMPACTS THE ENTIRE AREA. MONDAY DOES NOT APPEAR TO BE AS FAVORABLE FOR PRECIPITATION AS HIGH PRESSURE BUILDING IN FROM THE NORTH PUSHES THE SURFACE BOUNDARY FURTHER SOUTH. FURTHERMORE, THE MAIN SURFACE LOW IS OVER SOUTHERN CALIFORNIA, DYNAMICS ARE MORE UNCERTAIN. CONSEQUENTLY LOWERED POPS SOME BUT STILL KEPT CHANCE POPS OVER THE AREA MONDAY AFTERNOON. MIN TEMPERATURES SHOULD VARY FROM THE UPPER 40S TO THE LOWER 50S SATURDAY AND SUNDAY NIGHTS. MAX TEMPERATURES SHOULD RISE TO THE LOWER TO MID 80S SUNDAY AND THEN COOL TO THE MID 60S TO AROUND 70 MONDAY. IN THE EXTENDED...(TUESDAY THROUGH FRIDAY)...ACTIVE WEATHER IS EXPECTED FOR THIS PART OF THE FORECAST. AN UPPER LEVEL TROUGH OVER THE SW CONUS WILL MOVE NORTHEAST AND PHASE INTO A TROUGH OVER THE PACIFIC NORTHWEST. NUMEROUS SHORTWAVES WILL MOVE THROUGH THE FLOW AND ACROSS THE CENTRAL PLAINS. THERE WILL BE A CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE FA ON A DAILY BASIS THROUGH FRIDAY. MIN TEMPERATURES WILL COOL TO THE UPPER 40S AND LOWER 50S. MAX TEMPERATURES SHOULD RANGE FROM 65 TO 70 TUESDAY WARMING TO THE 70S WEDNESDAY THROUGH FRIDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1115 PM MDT FRI MAY 1 2015 KGLD...VFR THROUGH THE PERIOD. SOUTHWEST WINDS 5-10KTS AT TAF ISSUANCE EXPECTED TO BACK TO THE SOUTH AT SIMILAR SPEEDS AROUND 19Z THEN SOUTHWEST NEAR 10KTS FROM 02Z THROUGH THE REST OF THE TAF PERIOD. THUNDERSTORMS ARE POSSIBLE AROUND OR OVER THE TERMINAL AFTER 02Z THUS VCTS WORDING. KMCK...VFR THROUGH THE PERIOD. LIGHT SOUTHWEST WIND AT TAF ISSUANCE EXPECTED THROUGH THE TAF PERIOD. MAY SEE A FEW SHOWERS FROM TAF ISSUANCE THROUGH 07Z AND VARIABLE WINDS GUSTING 20KTS OR SO POSSIBLE. OTHERWISE...NO PRECIPITATION EXPECTED. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JN SHORT TERM...DR LONG TERM...FS AVIATION...99
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1133 PM CDT Fri May 1 2015 ...Update to aviation forecast discussion... .SHORT TERM...(This Evening through Saturday) Issued at 333 PM CDT FRI MAY 1 2015 19Z water vapor shows a ridge of high pressure centered over the AZ/NM boarder and broad cyclonic flow from the Gulf of AK through western Canada. Within this pattern, much of the shortwave activity remains along the Canadian boarder. At the surface, a ridge of high pressure was centered over the MS river valley with a weak trough of low pressure from northwest KS through the eastern Dakotas. For tonight and Saturday, there are two potential sources for forcing convection, and confidence in either one is rather so-so. The first is a possible convectively induced vort max (MCV) coming off the central Rockies this evening. The HRRR and RAP have been the most aggressive in holding precip together off the higher terrain and into the forecast area through Saturday morning. These solutions have also be to aggressive in this afternoon`s precip so I don`t know how much weight to put behind this idea with the GFS and NAM shearing out any MCV. At this point, have taken a wait and see approach for the convection to fully move off the mountains. Additionally the MCV may tend to move just southwest of the forecast area. The second forcing mechanism may end up being the low level jet and isentropic lift. The NAM and GFS seem to favor this, developing precip along the NEB state line and moving it into northern MO Saturday morning. However it appears the low level jet will be veered to the southwest with the stronger wind speeds to the west of the area. Additionally theta-e advection is marginal with the low level jet. The models do prog some isentropic lift over far northeast KS which may explain why they are generating precip. Nevertheless confidence is marginal since the low level jet itself is not very strong and moisture advection with the jet is weak. Have kept some 20 to 30 percent POPs across the northern counties through the morning to account for the possibility. Lows tonight should be a little more mild with readings remaining in the lower and mid 50s. Think skies are likely to remain at least partly cloudy with debris clouds spreading in from the west, helping to keep lows in the 50s. Models show some warm air advection through the day Saturday as low level flow remains southerly. Based on 850 temp progs and some insolation through the afternoon, think highs should warm into the upper 70s and lower 80s. .LONG TERM...(Saturday Night through Friday) Issued at 333 PM CDT FRI MAY 1 2015 Increasing low level southerly flow Saturday night into Sunday brings precipitable water values further above normal to near 1.5 inches. Main forcing mechanism approaches Sunday afternoon as a northern branch wave allows a cold front to settle south into the area, likely from southwest Kansas into east central Nebraska. Could see far western locations impacted late in the afternoon as storms could fire not far to the west-southwest, but chances increase in the next few periods as the front ceases its southerly push, between the northern and southern branches. Just how far the front gets is obviously a challenge and will be key for precip potential. Have tapered southern end of precip chances for Sunday night, with best mean chances Monday into Monday night until southerly flow returns to the northwest, ushering the front back north. At this point Tuesday appears the most likely dry period, with a modest but increasingly powerful upper wave rotating northeast into the Plains Tuesday night into Wednesday night. Expect most locations to see at least some precip in this period with deep south flow keeping available moisture plentiful. Beyond this, model differences increase for a much less confidence forecast, though a modified front could be in play with a still warm and moist airmass to support chance PoPs. As for thunderstorm severity, mid/upper flow is not very strong being between the northern and southern branches. With greater confidence in the late weekend/early next week boundary in the vicinity, there will of course be low level shear potential here with ML CAPE likely around 1500 J/kg. In the latter wetter period, the wave`s orientation keeps winds somewhat unidirectional with height, and instability specifics anything but certain with periodic precip quite likely. Expect highs to be generally near to a few degrees above normal, with main problem being depth/persistence of cloud/precip north of the front Monday to bring possibly cooler temps possible in northern areas. && .AVIATION...(For the 06Z TAFs through 06Z Saturday Night) Issued at 1128 PM CDT FRI MAY 1 2015 VFR conditions expected through most of the taf period. Low level wind shear was not well forecasted by the models therefore have added a group based on current observations. The models are also hinting at a shortwave tracking across the area during mid day. An isolated shower or storm could be possible with this feature although confidence was too low at this point to mention. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Wolters LONG TERM...65 AVIATION...Sanders
AREA FORECAST DISCUSSION
NWS DULUTH MN
325 PM CDT SAT MAY 2 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 324 PM CDT SAT MAY 2 2015 A SFC LOW WAS MOVING INTO NW ONTARIO AT 19Z WITH A TRAILING COLD FRONT SWWD INTO WESTERN ND. A SFC TROF WAS ALSO FOUND IN CENTRAL ND. THUNDERSTORMS WERE FIRING AHEAD OF THIS TROF IN THE VCNTY OF EMBEDDED PIECES OF ENERGY IN FAST ZONAL FLOW ALOFT. AN AREA OF SFC FGEN WAS ALSO CO-LOCATED WITH THE STORMS. EXPECT THIS LINE OF STORMS TO REACH NW MN BY 21Z. THE STORMS WILL CONTINUE TO MOVE EWD AND REACH THE NW CORNER OF KOOCHICHING COUNTY BY 01Z. HOWEVER...IT IS AT THIS POINT IN TIME WHEN THE STORMS BEGIN TO ENCOUNTER DRIER AIR THAT HAS BEEN CAMPED OUT OVER THE FORECAST AREA. LATEST SHORT TERM HIRES MODELS INCLUDING THE HRRR AND RAP SHOW THIS TREND AS WELL. AS THIS INITIAL ROUND OF STORMS DISSOLVES...THE NEXT ROUND WILL BEGIN TO DEVELOP OVER THE WESTERN HALF OF THE AREA AROUND 06Z AS THE SFC FRONT MAKES PROGRESS EWD INTO THE REGION. A LOW LEVEL INVERSION SEEN ON AREA FORECAST SOUNDINGS INDICATE THAT THESE STORMS WILL BE ELEVATED IN NATURE. ON SUNDAY...THE FRONT WILL PROGRESS SLOWLY EWD THROUGH THE DAY. SOME WEAK THUNDERSTORMS WILL BE AROUND IN THE MORNING AS A THERMAL RIDGE AXIS IS OVER THE REGION AND INSTABILITY IS WEAK. BY AFTERNOON...THE FRONT PUSHES INTO NW WI WITH MAX HEATING...STORMS WILL BECOME A BIT MORE VIGOROUS...AND BORDER ON SEVERE. SBCAPE INCREASES TO NEAR 3000 J/KG AND LI/S TO -8C PER FORECAST SOUNDINGS. SHOULD SEE SOME STORMS NEAR SEVERE WITH LARGE HAIL AND BRIEF HEAVY RAIN AS PWATS ARE 1 TO 1.25 INCHES. MODELS COME INTO AGREEMENT WITH THIS SOLUTION AND HAVE ROBUST QPF BY 00Z MONDAY. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 324 PM CDT SAT MAY 2 2015 SUNDAY EVENING THE COLD FRONT MOVES SOUTHEAST AWAY FROM THE AREA...AND WHILE I HAVE MAINTAINED SOME POPS FOR THE EVENING HOURS...EXPECT THEY WILL ONLY BE ONGOING AT THE VERY BEGINNING OF THE PERIOD AND EXIT QUICKLY DURING THE EVENING. A COOLER AND DRIER AIRMASS MOVES INTO THE AREA AFTER MIDNIGHT AND WILL LINGER THROUGH MONDAY AND MONDAY NIGHT. LOWS SUNDAY NIGHT AND MONDAY NIGHT TO FALL INTO THE MID 30S TO MID 40S FOR MUCH OF THE AREA...WITH HIGHS MONDAY BACK IN THE 60S TO AROUND 70. THE UPPER LEVEL PATTERN IS EXPECTED TO SHIFT TO A LONGWAVE TROUGH OVER THE WEST COAST AND ROCKIES...WITH WEAK RIDGING TO ZONAL FLOW OVER THE EASTERN CONUS. THIS TROUGHINESS TO OUR WEST IS GOING TO SENT A STRONG...SLOW MOVING UPPER LEVEL LOW SHORTWAVE ACROSS THE UPPER MIDWEST TUESDAY THROUGH FRIDAY...WITH SOME FAIRLY HIGH CHANCES FOR PRECIPITATION DURING THE PERIOD. TEMPERATURES WILL ALSO BE ABOVE NORMAL WITH HIGHS IN THE 70S EVEN WITH INCREASED CLOUD COVER AND PRECIPITATION. THIS SYSTEM TO MOVE OFF TO THE NORTHEAST BY SATURDAY...BUT THE UPPER LEVEL PATTERN OF A TROUGH OUT WEST REMAINS WITH WARM AIR STILL BEING FUNNELED IN OUR DIRECTION AND SOME LINGERING PRECIPITATION CHANCES INTO THE WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1245 PM CDT SAT MAY 2 2015 A COLD FRONT WILL TRIGGER SHOWERS AND THUNDERSTORMS AS IT TRACKS ACROSS NORTHWEST MINNESOTA THIS EVENING. THERE IS SOME UNCERTAINTY IN TIMING AND WHETHER THE STORMS WILL HOLD TOGETHER AS THEY REACH THE KINL AREA...AND HAVE PUT IN ONLY A PROB30 GROUP AT THIS TIME...WITH NO THUNDER IN ANY OF THE OTHER TAFS...JUST VCSH GROUPS AS THE FRONT MOVES THROUGH. AHEAD OF THE FRONT...WINDS ALOFT AT 1.5-2 KFT INCREASE TO 30-35 KTS FOR 06Z-12Z LATE TONIGHT. HAVE ADDED LLWS FOR KDLH AND KHIB...AND MAY NEED TO ALSO BE ADDED FOR KHYR AS WELL. ADDITIONAL THUNDERSTORM ACTIVITY IS EXPECTED AFTER 18Z SUNDAY...BUT MAINLY FOR KHYR. && .PRELIMINARY POINT TEMPS/POPS... DLH 52 77 44 67 / 10 40 0 0 INL 48 73 38 66 / 10 10 0 0 BRD 54 76 44 70 / 30 30 0 0 HYR 53 77 44 70 / 10 60 20 0 ASX 53 80 44 67 / 10 60 10 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR MNZ010-018-025- 026. WI...NONE. LS...NONE. && $$ SHORT TERM...GSF LONG TERM...LE AVIATION...LE
AREA FORECAST DISCUSSION
NWS DULUTH MN
351 AM CDT SAT MAY 2 2015 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 351 AM CDT SAT MAY 2 2015 VERY WARM THIS WEEKEND WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS THIS EVENING THROUGH SUNDAY AS A COLD FRONT WORKS ITS WAY EAST ACROSS THE REGION. HAVE SOME CONCERNS RELATED TO JUST HOW FAR EAST THE PRECIPITATION MAKES IT TONIGHT...BUT SUNDAY LOOKS FAIRLY WET ACROSS PORTIONS OF NORTHWEST WISCONSIN. TEMPS WILL BE IN THE MID 70S TO NEAR 80 TODAY...WELL ABOVE NORMAL BUT NOT NEARING ANY RECORD HIGHS. COOLER TOMORROW BEHIND THE COLD FRONT. EARLY THIS MORNING PATCHY FOG HAS DEVELOPED IN PORTIONS OF INLAND NORTHEAST TO EAST CENTRAL MINNESOTA...BUT DO NOT EXPECT FOG TO LAST VERY LONG PAST SUNRISE. TODAY...MOSTLY SUNNY AND WARM WITH SOUTHWEST WINDS OF 10 TO 15 MPH. DRY...WITH RELATIVE HUMIDITY FALLING TO 20 TO 30 PERCENT ACROSS MUCH OF NORTH-CENTRAL MINNESOTA. WINDS IN THIS REGION WILL GUST TO OVER 25 MPH AT TIMES DUE TO DEEP MIXING...SEE THE LATEST FIRE WEATHER FORECAST FOR MORE DETAILS WITH REGARD TO FIRE WEATHER RISK. AS A COLD FRONT APPROACHES FROM THE WEST THERE WILL BE INCREASING CLOUDS IN THE FORM OF CU ACROSS NORTH-CENTRAL MINNESOTA....MAINLY FROM LEECH LAKE TO INTERNATIONAL FALLS AND POINTS WEST BY THE LATE AFTERNOON. TEMPERATURES VERY WARM...IN THE MID 70S TO NEAR 80 INLAND...BUT AS COOL AS THE MID 50S TO MID 60S ADJACENT TO LAKE SUPERIOR...WITH COOLER TEMPS MOVING INLAND ACROSS PORTIONS OF THE NORTH SHORE DUE TO SOUTH TO SOUTHEAST WINDS OVER THE LAKE. TONIGHT...A LINE OF SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS NORTH CENTRAL MINNESOTA EARLY THIS EVENING BUT LIKELY DISSIPATE AS THEY MOVE INTO NORTHEAST MINNESOTA TONIGHT. KEPT POPS GOING OVERNIGHT WHERE THE BEST EML WILL BE LOCATED...BUT THINK DRY AIR AT LOW LEVELS WILL CAUSE THE LINE OF PRECIP TO GENERALLY DISSIPATE BY MIDNIGHT. MOST OF THE CONVECTION-ALLOWING GUIDANCE SUPPORTS THIS SOLUTION...THOUGH SOME OF THE PARAMETERIZED GUIDANCE SUCH AS THE ECMWF DEPICT A MUCH MORE MOIST ENVIRONMENT SUSTAINING PRECIP OVERNIGHT. BELIEVE THIS TO BE DUE TO OVERSATURATION AT MID AND UPPER LEVELS...AND THUS THINK THIS SOLUTION IS OVERDONE. GEM OFFERS A REASONABLE COMPROMISE OF THE AVAILABLE GUIDANCE...SO LEANED TOWARDS THIS FOR THE OVERNIGHT POPS. TEMPS MILD OVERNIGHT DUE TO CLOUDS COVER ALONG/BEHIND THE FRONT AND SW FLOW LEADING TO CONTINUED WAA AHEAD OF THE FRONT...IN THE UPPER 40S NEAR THE LAKE TO LOW/MID 50S MOST LOCATIONS INLAND...WHICH IS 10 TO 20 DEGREES ABOVE NORMAL. SUNDAY...AFTER A LULL IN PRECIP LATE SAT NIGHT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL DEVELOP. MLCAPE OF 500 TO 1500 WILL BE MORE THAN ENOUGH TO SUPPORT A FEW STRONG THUNDERSTORMS...WITH SMALL HAIL AND GUSTY WINDS THE MAIN THREAT. PWAT VALUES WILL BE ABOVE NORMAL AT JUST OVER AN INCH ACROSS NORTHWEST WISCONSIN...WITH A TALL AND SKINNY CAPE PROFILE SUPPORTING THE POSSIBILITY OF MODERATE TO LOCALLY HEAVY RAINFALL...WITH SOME LOCATIONS REVIVING OVER A HALF INCH OF RAINFALL SUNDAY AFTERNOON. HIGH TEMPS COOLER...IN THE LOW TO MID 70S. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 351 AM CDT SAT MAY 2 2015 THE COLD FRONT WILL PASS OVER WISCONSIN SUNDAY EVENING...EXITING TO THE EAST BY MIDNIGHT. SCATTERED STORMS WILL BE LIKELY IN THE HAYWARD TO PARK FALLS AREA DURING THE EVENING HOURS. SFC HIGH PRESSURE WILL BUILD OVER MN LATE SUNDAY NIGHT...CENTERING OVER THE WESTERN LAKE SUPERIOR REGION MONDAY. MODELS ARE IN GOOD AGREEMENT THAT A VORT MAX TRANSLATES ALONG THE INTERNATIONAL BORDER SUNDAY NIGHT/MONDAY...ALLOWING FOR COOLING TEMPS ALOFT AND H85 TEMPERATURES TO DIP INTO THE SINGLE DIGITS MONDAY. ALTHOUGH HIGH TEMPS WILL BE SLIGHTLY COOLER /IN THE 60S MONDAY/...THE DRY AIR MASS AND STEEP LAPSE RATES WILL PROMOTE DEEP MIXING AND LOW RH VALUES AROUND 20 PERCENT. WINDS WILL GENERALLY BE OUT OF THE NORTHWEST TO NORTH WITH AFTERNOON GUSTS AROUND 15 MPH. FOCUS TURNS TO LONG WAVE TROUGH IN THE PACIFIC NORTHWEST...THAT EJECTS A SHORT WAVE INTO THE UPPER PLAINS MID-WEEK. THE WAVE WILL LIFT A WARM FRONT ACROSS THE NORTHLAND TUESDAY NIGHT/WEDNESDAY...BRINGING A TRANSITION TO GUSTY SOUTHERLY WINDS /EXCEPT EAST NEAR LAKE SUPERIOR/ AND INCREASING MOISTURE. LONG RANGE MODELS SHOW A TREND TOWARDS A WET PERIOD AS THE WAVES ORGANIZES INTO A SFC LOW OVER THE DAKOTAS WED NIGHT...AND SLOWLY MIGRATES EAST ACROSS MINN THROUGH THE END OF THE WEEK. THE PROLONGED PERIOD OF RETURN FLOW AND SLOW MOVING LOW PRESSURE SYSTEM WILL BRING THE POTENTIAL FOR WIDESPREAD, LONG DURATION, RAINFALL ACROSS MUCH OF THE FORECAST AREA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 100 AM CDT SAT MAY 2 2015 VFR CONDITIONS EXPECTED AT ALL TERMINALS THROUGH THE FORECAST PERIOD. WINDS WILL BECOME VERY LIGHT TONIGHT. THE LATEST 00Z GUIDANCE ALONG WITH THE LAST SEVERAL HRRR RUNS HAVE BACKED OFF ON FOG DEVELOPING AT KDLH AND KHIB. FELT CONFIDENT ENOUGH TO KEEP FOG OUT OF THE FORECAST. RIDGING WILL OCCUR OVER THE MID ATLANTIC ON SATURDAY...THIS WILL ALLOW SSW WINDS TO DEVELOP AT ALL TERMINALS. DAY TIME HEATING ALONG WITH VERY DRY AIR IN THE LOWER LEVELS WILL ALLOW GUSTY WINDS TO DEVELOP DURING THE AFTERNOON AT ALL SITES EXCEPT FOR KHYR. LATE SATURDAY AFTERNOON A COLD FRONT WILL MOVE INTO WESTERN MINNESOTA FROM THE DAKOTAS. THIS WILL ALLOW SHOWERS AND PERHAPS A FEW THUNDERSTORMS TO DEVELOP. STILL UNCERTAIN ON THE EXTENT OF THE THUNDERSTORM ACTIVITY...SO KEPT VCSH AT KINL AND KBRD. && .PRELIMINARY POINT TEMPS/POPS... DLH 73 52 72 43 / 10 20 50 0 INL 80 49 72 38 / 20 20 20 0 BRD 77 54 73 43 / 10 30 40 0 HYR 75 54 75 43 / 10 0 80 20 ASX 76 51 75 43 / 10 10 80 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 8 PM CDT THIS EVENING FOR MNZ010-018-025-026. WI...NONE. LS...NONE. && $$ SHORT TERM...JJM LONG TERM...GRANING AVIATION...GRANING/WL
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
101 AM CDT SAT MAY 2 2015 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 401 PM CDT FRI MAY 1 2015 WEAKENING FRONTAL ZONE CURRENTLY BISECTING THE DULUTH CWA FROM SW TO NE SHOULD SLOWLY WASH OUT OVERNIGHT TONIGHT AS THE PARENT WAVE IN ONTARIO CONTINUES TO PULL AWAY FROM THE REGION AND WEAKEN. A FAIR AMOUNT OF BOUNDARY LAYER CUMULUS HAS DEVELOPED THIS AFTERNOON FROM THE BRAINERD AREA NEWD TO THE MN ARROWHEAD..SO A FEW ISOLATED SHOWERS CANNOT BE RULED OUT WITHIN THE WEAKENING FRONTAL ZONE ACROSS EASTERN MN/THE ARROWHEAD/NW WISCONSIN. HOWEVER..WE EXPECT ANY SHOWERS..IF THEY OCCUR AT ALL..TO BE QUITE SHORT LIVED. WEAK LOW LEVEL RIDGING WILL TAKE HOLD OVERNIGHT..WITH CLEARING SKIES AND LIGHT WINDS. TEMPS SHOULD BE ABLE TO DROP FAIRLY RAPIDLY..ESPECIALLY IN AREAS THAT CLEAR SOONER. SOME AREAS OF FOG ARE ALSO EXPECTED OVERNIGHT OVER THE EASTERN HALF OF THE CWA. THE MAIN CONCERN ON SATURDAY WILL BE THE CRITICAL FIRE WEATHER CONDITIONS THAT ARE EXPECTED TO DEVELOP..ESPECIALLY ACROSS THE NW PARTS OF THE CWA. WHILE THE STRONGEST S/SW WINDS ARE EXPECTED TO REMAIN TO THE WEST OF OUR AREA ACROSS THE RED RIVER VALLEY..TEMPS SHOULD RISE TO NEAR THE WARMEST READINGS OF THE SPRING SO FAR.. WITH UPPER 70S OR EVEN LOWER 80S OVER THE WESTERN QUARTER TO THIRD OF THE CWA. MOISTURE RETURN WILL BE MEAGER AHEAD OF THE NEXT SYSTEM..AT LEAST INITIALLY..AND WITH VEGETATION STILL NOT IN A ROBUST GREEN UP STATE..BOUNDARY LAYER MOISTURE SHOULD PLUMMET TO HUMIDITY VALUES LESS THAN 20 PERCENT IN MANY AREAS SAT AFTERNOON/EVENING OUT WEST. WE COORDINATED A FIRE WEATHER WATCH WITH THE FGF OFFICE AND MIFC FOR KOOCHICHING/ITASCA AND NORTHERN CASS COUNTIES FROM 11 AM THROUGH 8 PM SATURDAY. A FEW SHOWERS/TSTORMS SHOULD INITIATE OVER ERN ND WITH THE NEXT FRONT SAT EVENING..BUT ANY PRECIP SHOULD TAKE UNTIL WELL AFTER 00Z SAT EVENING TO REACH NCENT MN. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 401 PM CDT FRI MAY 1 2015 A COLD FRONT WILL MOVE WNW TO ESE ACROSS NE MINNESOTA AND NW WISCONSIN SUNDAY. MOST OF THE MODELS CONTINUE TO INDICATE THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS WITH THE PASSING FRONT. THE HIGHEST CHANCES FOR SHOWERS AND STORMS IS NW WISCONSIN DURING THE AFTERNOON AND EVENING OF SUNDAY. THIS IS ALSO WHERE THERE COULD BE STRONG TO NEARLY SEVERE THUNDERSTORMS. AT THIS TIME...IT APPEARS THERE WILL BE SUFFICIENT INSTABILITY AND WIND SHEAR TO SUPPORT STRONG TO SEVERE THUNDERSTORMS. THE PRECIPITABLE WATER VALUES WILL CLIMB TO NEARLY 1.5 INCHES IN THE SE FORECAST AREA...SO NW WISCONSIN COULD ALSO GET HEAVY RAIN. HIGH PRESSURE WILL MOVE INTO THE NORTHLAND EARLY NEXT WEEK...PROVIDING WARM AND DRY WEATHER MONDAY AND TUESDAY. THE GFS/GEM/ECMWF CONTINUE TO INDICATE THAT A LOW PRESSURE IN THE HIGH PLAINS NEAR COLORADO WILL LIFT INTO THE NORTHERN PLAINS AND CANADA WEDNESDAY AND THURSDAY. THE WARM FRONT ASSOCIATED WITH THE LOW PRESSURE WILL LIFT INTO THE NORTHERN PLAINS AND UPPER MIDWEST. THE NORTHLAND WILL SEE A PERIOD OF WARM AND MORE HUMID SOUTHERLY FLOW WITH AN EXTENDED PERIOD OF HIGHER CHANCES OF SHOWERS AND THUNDERSTORMS FOR WEDNESDAY THROUGH AT LEAST THURSDAY. THE RAINS COULD BRING RELIEF TO DROUGHT STRICKEN MINNESOTA AND WISCONSIN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 100 AM CDT SAT MAY 2 2015 VFR CONDITIONS EXPECTED AT ALL TERMINALS THROUGH THE FORECAST PERIOD. WINDS WILL BECOME VERY LIGHT TONIGHT. THE LATEST 00Z GUIDANCE ALONG WITH THE LAST SEVERAL HRRR RUNS HAVE BACKED OFF ON FOG DEVELOPING AT KDLH AND KHIB. FELT CONFIDENT ENOUGH TO KEEP FOG OUT OF THE FORECAST. RIDGING WILL OCCUR OVER THE MID ATLANTIC ON SATURDAY...THIS WILL ALLOW SSW WINDS TO DEVELOP AT ALL TERMINALS. DAY TIME HEATING ALONG WITH VERY DRY AIR IN THE LOWER LEVELS WILL ALLOW GUSTY WINDS TO DEVELOP DURING THE AFTERNOON AT ALL SITES EXCEPT FOR KHYR. LATE SATURDAY AFTERNOON A COLD FRONT WILL MOVE INTO WESTERN MINNESOTA FROM THE DAKOTAS. THIS WILL ALLOW SHOWERS AND PERHAPS A FEW THUNDERSTORMS TO DEVELOP. STILL UNCERTAIN ON THE EXTENT OF THE THUNDERSTORM ACTIVITY...SO KEPT VCSH AT KINL AND KBRD. && .PRELIMINARY POINT TEMPS/POPS... DLH 51 72 43 66 / 10 50 0 0 INL 51 70 38 67 / 30 10 0 0 BRD 54 73 43 70 / 30 50 0 0 HYR 54 75 43 69 / 0 70 30 0 ASX 53 74 43 69 / 0 60 20 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...FIRE WEATHER WATCH FROM 11 AM CDT THIS MORNING THROUGH THIS EVENING FOR MNZ010-018-025-026. WI...NONE. LS...NONE. && $$ AVIATION...GRANING/WL
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1234 PM CDT Sat May 2 2015 .UPDATE... Issued at 907 AM CDT SAT MAY 2 2015 Raised PoPs over most of the CWA to account for ongoing convection over the northwest third of the forecast area as well as the approaching activity now over central KS. The northwest MO activity is associated with moderately strong isentropic ascent on the 300K and 305K surfaces as well as support from a shortwave trough moving east across NE. The KS activity is associated with a weak mid-level vorticity trough and vorticity max. The 12z NAM picks up on the KS vorticity max and even strengthens it as it moves into northwest MO. Not quite buying the strengthening process nor the placement but do expect the feature to persist as it moves east into the CWA. The HRRR model trend maintains a steady flow of scattered showers being generated over southeast NE and moving into northwest MO while the initial activity weakens as it moves into northeast MO. The HRRR also holds onto the KS activity as it crosses into west central MO by 18z as well as continuing east into the central portion of the forecast area. What this all means is a need to increase PoPs and clouds across the CWA and a need to lower temperatures across the northern half of the CWA where PoPs are highest. Will monitor cloud/precipitation trends as there is a good chance we`ll need to lower temperatures further over the west central CWA. One last item is we`ve stripped away thunder from the forecast as the instability is puny and not expected to increase. There may be a stray cg strike in the far northwest near the southern edge of the stronger isentropic ascent and where lightning is occurring over southwest IA. && .DISCUSSION... Issued at 351 AM CDT SAT MAY 2 2015 Today/Tonight: Several subtle upper disturbances will move through the region, aiding in the development of scattered convection. The most probable locations to receive light measurable precipitation will be along and north of the Interstate 70 corridor. The most active period should coincide with the approach of these impulses, with this morning into the early afternoon one round, and another possible overnight. Modest instability will gradually increase from west to east during the day, and therefore a few scattered thunderstorms will be possible this morning into the evening. Temperatures should warm well into the 70s during the afternoon, even with broken cloud cover. Overnight temperatures will remain in the lower 60s to upper 50s in part to increased moisture advection and cloud cover. Sunday/Monday: A large upper trough skirting the US/Canada border will send a cold front approaching the area by Sunday night. This will be the primary focus for the most spatially concentrated area for convection during this period. The front is expected to settle near northwest Missouri on Monday before stalling, and with strong daytime heating, convection is expected to develop over NW MO. Deep layer shear is expected to be rather weak, unless a subtle upper disturbance not yet resolvable can enhance speeds, although moderate instability around MUCAPE 1500 J/kg will develop ahead of the boundary. While severe weather is not likely, a few stronger storms may evolve during the afternoon and evening hours. Tuesday through Saturday: An active pattern looks to evolve across much of the region, albeit severe weather probabilities still appear low/uncertain at this time. A negatively-tilted shortwave trough is projected to lift into the Plains Tuesday into Wednesday. In its wake, continued southwesterly flow will establish over the region, with several embedded upper disturbances expected to move through. While specific details are not resolvable in this period for this particular pattern, it is reasonable to believe several episodes of convection will be possible for portions of the area. Questions regarding an initial meridional wind field and the degree of destabilization limits confidence/signal for severe weather. As for temperatures, above normal readings are expected to continue, with highs in the 70s and 80s. && .AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon) Issued at 1228 PM CDT SAT MAY 2 2015 VFR conditions this afternoon despite thick mid level ceilings around 10k ft and showers. An area of showers with pockets of MVFR ceilings with the heavier showers will slowly shift east across northern MO this afternoon. Activity should gradually weaken. Band of spotty showers over eastern KS will also track east and affect the west central MO terminals through mid afternoon, then clouds thin out. Increasingly southwesterly low level jet will advance east overnight. Expect these winds to reach the ground by mid morning resulting in gusty conditions. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ UPDATE...MJ DISCUSSION...Blair AVIATION...MJ
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
919 AM CDT Sat May 2 2015 .UPDATE... Issued at 907 AM CDT SAT MAY 2 2015 Raised PoPs over most of the CWA to account for ongoing convection over the northwest third of the forecast area as well as the approaching activity now over central KS. The northwest MO activity is associated with moderately strong isentropic ascent on the 300K and 305K surfaces as well as support from a shortwave trough moving east across NE. The KS activity is associated with a weak mid-level vorticity trough and vorticity max. The 12z NAM picks up on the KS vorticity max and even strengthens it as it moves into northwest MO. Not quite buying the strengthening process nor the placement but do expect the feature to persist as it moves east into the CWA. The HRRR model trend maintains a steady flow of scattered showers being generated over southeast NE and moving into northwest MO while the initial activity weakens as it moves into northeast MO. The HRRR also holds onto the KS activity as it crosses into west central MO by 18z as well as continuing east into the central portion of the forecast area. What this all means is a need to increase PoPs and clouds across the CWA and a need to lower temperatures across the northern half of the CWA where PoPs are highest. Will monitor cloud/precipitation trends as there is a good chance we`ll need to lower temperatures further over the west central CWA. One last item is we`ve stripped away thunder from the forecast as the instability is puny and not expected to increase. There may be a stray cg strike in the far northwest near the southern edge of the stronger isentropic ascent and where lightning is occurring over southwest IA. && .DISCUSSION... Issued at 351 AM CDT SAT MAY 2 2015 Today/Tonight: Several subtle upper disturbances will move through the region, aiding in the development of scattered convection. The most probable locations to receive light measurable precipitation will be along and north of the Interstate 70 corridor. The most active period should coincide with the approach of these impulses, with this morning into the early afternoon one round, and another possible overnight. Modest instability will gradually increase from west to east during the day, and therefore a few scattered thunderstorms will be possible this morning into the evening. Temperatures should warm well into the 70s during the afternoon, even with broken cloud cover. Overnight temperatures will remain in the lower 60s to upper 50s in part to increased moisture advection and cloud cover. Sunday/Monday: A large upper trough skirting the US/Canada border will send a cold front approaching the area by Sunday night. This will be the primary focus for the most spatially concentrated area for convection during this period. The front is expected to settle near northwest Missouri on Monday before stalling, and with strong daytime heating, convection is expected to develop over NW MO. Deep layer shear is expected to be rather weak, unless a subtle upper disturbance not yet resolvable can enhance speeds, although moderate instability around MUCAPE 1500 J/kg will develop ahead of the boundary. While severe weather is not likely, a few stronger storms may evolve during the afternoon and evening hours. Tuesday through Saturday: An active pattern looks to evolve across much of the region, albeit severe weather probabilities still appear low/uncertain at this time. A negatively-tilted shortwave trough is projected to lift into the Plains Tuesday into Wednesday. In its wake, continued southwesterly flow will establish over the region, with several embedded upper disturbances expected to move through. While specific details are not resolvable in this period for this particular pattern, it is reasonable to believe several episodes of convection will be possible for portions of the area. Questions regarding an initial meridional wind field and the degree of destabilization limits confidence/signal for severe weather. As for temperatures, above normal readings are expected to continue, with highs in the 70s and 80s. && .AVIATION...(For the 12Z TAFS through 12Z Sunday Morning) Issued at 548 AM CDT SAT MAY 2 2015 VFR anticipated through the period. Scattered convection near terminals should result in minimal impacts. Scattered precipitation should clear area by mid-afternoon. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ UPDATE...MJ DISCUSSION...Blair AVIATION...Blair
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
902 AM MDT SAT MAY 2 2015 .UPDATE... FORECAST WAS IN GOOD SHAPE THIS MORNING. ONLY CHANGES WERE TO INCREASE WIND SPEEDS OVER SOME AREAS DUE TO WINDS ALREADY KICKING UP IN KLVM...KBIL AND KBHK...AND DUE TO THE STRONG INVERTED-V NATURE OF RAP SOUNDINGS AND GOOD W FLOW THROUGH THE COLUMN. ALSO ADJUSTED MORNING SKY COVER WITH SATELLITE IMAGERY SHOWING AREAS OF HIGH CLOUDINESS ACROSS THE REGION. COLD FRONT WAS ENTERING N MT PER 14Z SURFACE OBSERVATIONS. FRONT WAS NOT OVERLY STRONG WITH ONLY A 10 DEGREE TEMPERATURE DIFFERENCE ACROSS THE BOUNDARY AND NO REAL DEWPOINT DIFFERENCE. MODELS HAD THE FRONT MOVING INTO THE NORTHERN FORECAST AREA BY 00Z...THEN SINKING S THROUGH THE REMAINDER OF THE AREA BY 06Z WITH SURFACE WINDS BECOMING NE. MODELS WERE IN GOOD AGREEMENT IN KEEPING THE PRECIPITATION CHANCES FOCUSED OVER THE S MOUNTAINS. OTHERWISE...LIFT WAS LIMITED WITH LITTLE JET DIVERGENCE AND ONLY WEAK FRONTOGENESIS. NOTED THE HRRR TRIED TO DEVELOP SOME CONVECTION NEAR KMLS...BUT WITH THE AIRMASS BEING SO DRY...THIS WILL NOT BE A CONCERN. TEMPERATURES AND RELATIVE HUMIDITIES WERE IN GOOD SHAPE TODAY. CONVECTION SHOULD PERSIST OVER THE MOUNTAINS INTO THIS EVENING THEN SHIFT E OVERNIGHT. ARTHUR && .SHORT TERM...VALID FOR TDY AND SUN... FAIRLY UNEVENTFULL WEEKEND IN STORE WITH THE EXCEPTION OF A COLD FRONT WHICH WILL MOVE ACROSS THE FORECAST AREA TODAY. A FAST AND MAINLY WESTERLY FLOW ALOFT WILL CONTINUE TODAY THROUGH MOST OF SUNDAY. A COLD FRONT WILL DROP SOUTH ACROSS THE AREA LATE THIS AFTERNOON BRINGING A WIND SHIFT TO THE NORTHWEST THEN NORTHEAST TONIGHT INTO SUNDAY. MODELS SHOW VERY LITTLE MOISTURE ASSOCIATED WITH THE FRONT BUT WE WILL CONTINUE WITH A SLIGHT SHOWER/THUNDERSTORM CHANCE...MAINLY OVER AND NEAR THE MOUNTAINS THIS AFTERNOON THROUGH THIS EVENING. TEMPERATURES TODAY WILL AGAIN BE ABOVE NORMAL WITH MOST AREAS WARMING INTO THE MIDDLE TO UPPER 70S WITH POSSIBLY AN 80 DEGREE READING FOR A FEW AREAS. STRONGER JET DYNAMICS STAY ALONG THE CANADIAN BORDER DURING THE DAY SUNDAY. HOWEVER...A SMALL DISTURBANCE WILL MOVE NORTH OUT OF COLORADO AND WYOMING DURING THE AFTERNOON AND EVENING. THIS DISTURBANCE WILL MAINLY STAY TO OUR SOUTH ACROSS WYOMING BUT THE NORTHERN EDGE MAY BRUSH OUR FAR SOUTHERN AREAS ALONG THE MONTANA/WYOMING BORDER SO WILL MAINTAIN A SLIGHT SHOWER CHANCE FOR THOSE AREAS. TEMPERATURES SUNDAY WILL BE COOLER AND CLOSER TO NORMAL FOR THIS TIME OF YEAR WITH READINGS IN THE 60S. HOOLEY .LONG TERM...VALID FOR MON...TUE...WED...THU...FRI... MODELS HAVE CONTINUED TO SHOW BETTER AGREEMENT WITH THE LATEST RUNS. THEY CONTINUE TO CONVERGE ON THE GENERAL SOLUTION THE GFS HAS BEEN PRESENTING OVER THE PAST SEVERAL RUNS OF A PACIFIC LOW MOVING ON SHORE AND INTO THE NORTHERN GREAT BASIN. THE SPECIFICS REMAIN UNCERTAIN. THERE REMAINS A LARGE SPREAD IN THE GFS ENSEMBLE WELL AS BETWEEN THE GFS...EC...AND GEM. WITH THE INCREASING CONFIDENCE...HAVE INCREASED POPS SLIGHTLY. ALSO THERE IS SOME CAPE DURING THE AFTERNOON ON WEDNESDAY...SO HAVE ADDED SOME THUNDERSTORMS WEDNESDAY. THE BEGINNING OF THE WEEK WILL SEE WARM TEMPERATURES...WITH THE AREA IN WESTERLY FLOW. WITH SOME LIFT AS A WEAK WAVE MOVES THROUGH THE FLOW. THE MOUNTAINS WILL HAVE A SLIGHT CHANCE FOR RAIN...AN ISOLATED THUNDERSTORM COULD MOVE OFF THE TERRAIN INTO THE WESTERN PLAINS. WITH INCREASED CLOUD COVER AND INCREASED RAIN CHANCES FOR THE SECOND HALF OF THE WEEK...TEMPERATURES WILL BE BACK NEAR NORMAL IN THE MID 60S. REIMER && .AVIATION... VFR EXPECTED OVER THE NEXT 24 HOURS. NO AVIATION HAZARDS EXPECTED. REIMER/FRIEDERS && .PRELIMINARY POINT TEMP/POPS... TDY SUN MON TUE WED THU FRI ------------------------------------------------------- BIL 078 045/066 044/077 048/078 047/063 043/053 038/060 0/B 11/B 11/B 22/T 43/T 44/W 33/W LVM 074 036/066 038/075 043/075 041/060 038/050 033/058 1/N 11/B 12/T 23/T 44/T 44/W 33/W HDN 081 042/069 042/080 045/079 047/065 041/053 035/062 0/B 11/B 21/B 12/T 43/T 44/W 32/W MLS 080 045/067 043/075 049/078 050/066 042/054 037/061 1/B 11/B 12/W 12/T 43/T 33/W 32/W 4BQ 080 044/067 044/073 047/076 049/064 043/054 035/061 0/B 11/B 32/T 12/T 44/T 43/W 22/W BHK 079 040/064 038/071 044/072 049/061 041/055 033/058 0/B 21/B 12/T 11/N 44/T 43/W 33/W SHR 077 043/065 043/071 043/073 045/061 040/053 033/057 0/B 12/W 22/T 23/T 44/T 44/W 33/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
343 PM CDT SAT MAY 2 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 341 PM CDT SAT MAY 2 2015 ONVECTION CHANCES HEADLINES THE SHORT TERM DISCUSSION. THE BEST CHANCES OF MEASURABLE QPF APPEARS TO COME LATE THIS AFTERNOON/EARLY EVENING...AND THEN AGAIN SUNDAY AFTERNOON. NEAR ZONAL FLOW ALOFT ACROSS THE CENTRAL PLAINS WILL PERSIST THROUGH THE SHORT TERM PERIOD...WITH A BROAD AREA OF HIGH PRESSURE LOCATED OVER THE SOUTH CENTRAL CONUS...AND A TROUGH NOTED NORTH OF THE CANADIAN BORDER...CURRENTLY NEAR ALBERTA. THIS PATTERN IS ALLOWING A LEE SURFACE TROUGH TO DEEPEN AND SLOWLY MOVE EASTWARD FROM THE HIGH PLAINS ONTO THE WESTERN SANDHILLS. AS OF 19Z...A QUICK SUBJECTIVE ANALYSIS OF THE SFC WOULD INDICATE THE TROUGH NOW EAST OF KAIA...LOCATED WEST OF A KOGA TO MRRR1 LINE. CONVECTIVE DEVELOPMENT HAS JUST BEGUN ALONG AND EAST OF THE TROUGH...FROM CENTRAL CHERRY COUNTY SOUTH TO NEAR KIML. THE CU IS WELL IN IT/S INFANCY STAGE...WITH FULL DEVELOPMENT LIKELY TWO 1-2 HOURS /OR MORE/ FROM NOW. DETERMINISTIC AND LATEST HI-RES GUIDANCE CONTINUES TO SHOW GOOD AGREEMENT IN TWO INITIAL AREAS OF TSTORMS...FIRST ACROSS SOUTHWEST NEBRASKA AND THE OTHER FROM CENTRAL CHERRY COUNTY SOUTH INTO THE CENTRAL SANDHILLS...HOWEVER THE LATEST 02/17Z SPC HRRR SUGGESTS A BROKEN LINE EXTENDING ACROSS MUCH OF THE SFC TROUGH...WITH THE LINE ADVANCING EAST WITH TIME. LOWER TROPOSPHERIC MOISTURE IS NOW DECREASING WITH THE INCREASED AFTERNOON MIXING...WITH MOST LOCATIONS TD/S NOW BELOW 10C. SO...NOT COMPLETELY BUYING INTO THE NOTION OF THE EXTENDED BROKEN LINE OF TSTORMS...BUT ISOLATED CONVECTION IS STILL ANTICIPATED. WILL CARRY ISO-SCT POPS EAST OF THE SFC TROUGH THROUGH THE FA THIS EVENING. LLJ DOES RAMP UP SLIGHTLY OVERNIGHT...MAY POSSIBLY SEE A LINGERING STORM ACROSS OUR EAST BEYOND 06Z...OR ADDITIONAL WEAK CONVECTION DEVELOP ELSEWHERE...BUT CHANCES WILL BE MINUSCULE AFTER 06Z TONIGHT. IN TERMS OF SEVERE...LATEST THERMO PARAMETERS INDICATE UPWARDS TO 1500-2000 J/KG OF MLCAPE...HOWEVER SHEAR IS MARGINAL WHERE TOWERS ARE CURRENTLY GOING UP...SO WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED THIS AFTERNOON OR EVENING...BUT A FEW STRONG/LOW-END SVR STORMS MAY PRODUCE HAIL OR ESPECIALLY GUSTY WIND AS SOUNDINGS REVEAL A INCREASING INVERTED-V PROFILE. SUNDAY...A COLD FRONT AND/OR SFC TROUGH WILL PROVIDE FOR A CHANCE OF ADDITIONAL STORM DEVELOPMENT DURING THE AFTERNOON HOURS...BUT THE BETTER FOCUS FOR WIDESPREAD STORMS APPEARS TO REMAIN EAST AND SOUTH OF THE FORECAST AREA. BY 21Z...STEEP LAPSE RATES WILL CONTRIBUTE TO UPWARDS OF 1000-1500 J/KG CAPE ACROSS NORTH CENTRAL NEBRASKA WITH FAVORABLE SHEAR FOR SOME DEVELOPMENT...THUS WILL MAINTAIN ISOLATED TO SCATTERED CHANCES OF STORMS ACROSS NORTH CENTRAL NEBRASKA DURING THE AFTERNOON HOURS. BETTER MOISTURE IN THE LOWER TROPOSPHERE WOULD ALLOW FOR SOME RAIN PRODUCING STORMS IN THIS AREA. ONCE AGAIN HOWEVER...WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 341 PM CDT SAT MAY 2 2015 UNSETTLED PERIOD AHEAD AS A LARGE LONG WAVE TROUGH WILL BE ESTABLISHED ACROSS THE WESTERN PORTION OF THE UNITED STATES THROUGH MUCH OF THE COMING WEEK. RAIN CHANCES LOOK GOOD FOR MUCH OF THE CENTRAL PLAINS AS A RESULT...WITH AT LEAST SOME CHANCE OF A FEW SCATTERED SEVERE THUNDERSTORMS. A COLD FRONT WILL SETTLE ACROSS NORTHERN KANSAS MONDAY. EXPECTING SHOWERS AND THUNDERSTORMS TO BE ONGOING ACROSS A GOOD PORTION OF WESTERN AND NORTH CENTRAL NEBRASKA MONDAY MORNING...AIDED BY A COMBINATION OF A SOUTHERLY LOW LEVEL JET NOSING INTO THE AREA AND A SHORTWAVE ALOFT EJECTING NORTHEAST ACROSS THE REGION. MAY BE A BIT OF A LULL IN THE PRECIPITATION MONDAY AFTERNOON AND MONDAY EVENING...BUT CANNOT COMPLETELY RULE OUT AT LEAST SOME SCATTERED SHOWERS/T-STORMS...ESPECIALLY AGAIN MONDAY NIGHT AS THE H850MB FRONT IS ANCHORED ALONG THE NEBRASKA KANSAS BORDER AND THE SOUTHERLY LOW LEVEL JET STRENGTHENS ONCE AGAIN. TUESDAY INTO WEDNESDAY APPEARS TO BE THE BEST CHANCE FOR PRECIPITATION. A STRONG SHORTWAVE WILL EJECT NORTHEAST FROM THE LONG WAVE TROUGH DURING THIS TIME. GOOD MODEL AND ENSEMBLE AGREEMENT THAT THIS WILL BE NEGATIVELY TILTED AS IT EMERGES ONTO THE PLAINS. HAVE INCREASED CHANCES FOR RAIN A FURTHER TUESDAY INTO WEDNESDAY...AS STRONG MOISTURE TRANSPORT AND STRONG LIFT SHOULD ENSURE RAIN. SOME INSTABILITY IN THE MID LEVELS...SO WILL KEEP THE THUNDER MENTION GOING. CERTAINLY COULD BE SOME STRONG OR PERHAPS EVEN A SEVERE STORM OR TWO DURING THIS TIMEFRAME...BUT MAY VERY WELL BE SOCKED IN WITH LOW CLOUDS DUE TO SUCH STRONG MOISTURE ADVECTION...AND THIS WOULD CUT DOWN ON SURFACE BASED INSTABILITY AND OTHERWISE MORE ROBUST SEVERE WEATHER THREAT. WILL CONTINUE TO MONITOR THIS PERIOD CLOSELY. ABOVE MENTIONED SHORTWAVE MOVES NORTHEAST AWAY FROM THE AREA THURSDAY...AND HAVE TRIED TO REFLECT THIS WITH ONLY SLIGHT OR LOW CHANCE POPS. THEN THE MAIN LONG WAVE TROUGH WILL EJECT EAST INTO THE CENTRAL AND NORTHERN PLAINS THURSDAY NIGHT THOUGH SATURDAY. AGAIN APPEARS A NEGATIVE TILT WITH THIS SYSTEM...WHICH WILL QUICKLY HELP PULL MOISTURE BACK INTO THE WESTERN HIGH PLAINS. MORE RAIN LIKELY AS THIS OCCURS INTO THE FIRST OF THE WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1249 PM CDT SAT MAY 2 2015 THUNDERSTORM CHANCES HEADLINE THE AVIATION DISCUSSION...WITH TWO POSSIBLE...ALBEIT SLIGHT...CHANCES OF STORMS IMPACTING PORTIONS OF THE SANDHILLS REGION. THE FIRST CHANCE COMES LATE AFTERNOON AND INTO THE EVENING HOURS TONIGHT WHEN A SFC TROUGH ADVANCES EAST ACROSS THE SANDHILLS. THE 02.12Z NAM AND LATEST HRRR SEEM TO BE A GOOD COMPROMISE IN THAT STORMS SHOULD FORM ACROSS THE HEART OF THE SANDHILLS AND POSSIBLY ACROSS SW NEBRASKA. THE SECOND CHANCE COMES LATE IN THE FORECAST PERIOD SUNDAY MORNING...WHERE NORTH CENTRAL NEBRASKA IS FAVORED FOR STORM DEVELOPMENT. BOTH INSTANCES STORMS WILL BE ISOLATED TO SCATTERED AT BEST...SO CONFIDENCE IN STORMS IMPACTING EITHER KVTN OR KLBF IS LOW...MAY NEED UPDATES. IF A STORM DOES IMPACT A TERMINAL...GUSTY ERRATIC WIND AND SMALL HAIL WOULD BE POSSIBLE. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JACOBS LONG TERM...TAYLOR AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1249 PM CDT SAT MAY 2 2015 .UPDATE... ISSUED AT 700 AM CDT SAT MAY 2 2015 PRECIPITATION ENDING OVER NORTH CENTRAL NEBRASKA EARLY THIS MORNING. SOME PATCHY FOG ALONG THE PLATTE RIVER VALLEY. SINCE IT IS SO LOCALIZED HAVE LEFT OUT OF THE FORECAST AND WILL COVER WITH NOWCASTS. UPDATED WEATHER...WINDS AND SKY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 322 AM CDT SAT MAY 2 2015 MODELS HAVE GOOD RUN TO RUN CONSISTENCY IN THE NEAR TERM AND HAVE GOOD CONFIDENCE IN THE FORECAST. FIRST CONCERN IS WHETHER TO INCLUDE PRECIP IN THE FORECAST THIS MORNING. THUNDERSTORMS INTO SOUTH CENTRAL CHERRY COUNTY, STORMS ARE MOVING TO THE EAST SOUTHEAST AROUND 20KTS AND THIS SHOULD HAVE MOST ACTIVITY CLEARING FORECAST AREA BY 1230Z. WILL CARRY A PRE FIRST PERIOD. TEMPERATURES AND PRECIPITATION THIS AFTERNOON AND THIS EVENING WILL BE MAIN FORECAST CHALLENGE. STILL 59F AT 1 AM CDT AT KLBF. CLEARING SKIES THIS MORNING AND LIGHT NORTH WINDS ON THE BACKSIDE OF WEAK DISTURBANCE WILL DROP TEMPERATURES TO AROUND 50F OVER MOST OF THE FORECAST AREA. VERY WARM START TO THE DAY. STRONG SOUTHERLY FLOW BEGINNING OVER NORTHWEST NEBRASKA AND EXPANDING EAST THROUGH WESTERN NEBRASKA THROUGH THE DAY. HEATING OF THE DAY TD`S IN THE LOW 50S AND WEAK FORCING IN THE AFTERNOON ALONG THE SURFACE TROUGH WITH SOME MARGINAL MUCAPE WILL BRING THE CHANCE FOR ISOLATED THUNDERSTORMS AGAIN ALONG THE TROUGH AXIS AND THEN SHIFTING EAST THROUGH THE DAY AND EARLY EVENING. WEAK LLJ WILL DEVELOP TO THE THE SOUTHWEST AND CARRY AND ENHANCE TRW AS THEY MOVE EAST. LLJ NOT AS STRONG 20 TO 25 KTS. DYNAMICS WILL DIMINISH THROUGH 6Z AND HAVE ENDED CHANCES AFTER THEN. LOWS AGAIN AROUND 50. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 322 AM CDT SAT MAY 2 2015 THE LONG TERM PERIOD IS FILLED WITH DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS AS A LONGWAVE TROUGH SETS UP OVER THE WESTERN CONUS. THE UPPER AIR PATTERN SUNDAY MORNING WILL BE HIGHLIGHTED BY A STRONG LOW OFF THE PAC NW COAST...AND A WEAKER LOW TO THE SOUTH OVER THE NORTHERN BAJA. THE SPLIT FLOW PHASES OVER THE CENTRAL CONUS AS A LOW AMPLITUDE BEGINS TO SET UP OVER THE EASTERN HALF OF THE CONUS. THE POSITION OF THE HIGH PRESSURE WILL OPEN UP THE GULF OF MEXICO EARLY NEXT WEEK AS MEAN SOUTHERLY LOW LEVEL FLOW DEVELOPS FROM THE YUCATAN PENINSULA NORTHWARD UP THE PLAINS. A COLD FRONT WILL SLOWLY MOVE OVER THE CWA SUNDAY...STRETCHING FROM SOUTHWEST TO NORTH CENTRAL NEBRASKA BY LATE AFTERNOON. THIS WILL LIKELY SERVE AS THE FOCUS FOR ISOLATED TO SCATTERED THUNDERSTORM DEVELOPMENT AS RICHER THETA-E AIR POOLS IN THE VICINITY OF THE SFC FRONTAL AXIS. STEEPENING MID LEVEL LAPSE RATES WILL SUPPORT A FEW STRONG TO MARGINALLY SEVERE STORMS...HOWEVER THE OVERALL SEVERE THREAT SHOULD BE LOW OWING TO A LACK OF QUALITY MOISTURE DEPTH...MEAGER DEEP LAYER SHEAR...AND WEAK UPPER LEVEL SUPPORT. THE FRONT STALLS OUT OVER KANSAS ON MONDAY AND EASTERLY UPSLOPE FLOW SETS UP OVER THE CWA. THIS WILL LEAD TO THE DEVELOPMENT OF WIDESPREAD CLOUDINESS...COOLER TEMPS...AND CONTINUED CHANCES FOR SHOWERS AND STORMS. THE GFS...EC...AND THEIR RESPECTIVE ENSEMBLES ARE IN FAIRLY GOOD AGREEMENT WITH THE EVOLUTION OF THE UPPER LEVEL PATTERN IN THE TUESDAY-WEDNESDAY TIMEFRAME. THE SOUTHERN STREAM PV EJECTS OUT OF THE DESERT SOUTHWEST TOWARD THE CENTRAL PLAINS. HEIGHT RISES OCCUR DOWNSTREAM AS THE UPPER LEVEL FLOW BECOMES NEARLY MERIDIONAL OVER THE CENTRAL CONUS. CROSS SECTIONS SHOW STRONG THETA-E ADVECTION IN THE LOW TO MID LEVELS WITH IMPRESSIVE MOISTURE TRANSPORT INTO WESTERN NEBRASKA. GFS PUSHES PWATS INTO THE 2+ STANDARD DEVIATIONS ABOVE CLIMO RANGE FOR NORTH PLATTE. WIDESPREAD SHOWERS AND STORMS APPEAR LIKELY AT THIS TIME...AS WELL AS A POSSIBILITY FOR LOCALIZED HEAVY RAINFALL. THE SEVERE THREAT TUESDAY AND WEDNESDAY IS TOUGH TO DISCERN AS THE WIDESPREAD AND PERSISTENT QPF CURRENTLY SHOWN IN THE MODELS WOULD LIKELY LIMIT THE DEGREE OF DESTABILIZATION. MODELS MAINTAIN DECENT AGREEMENT WITH THEIR HANDLING OF SYNOPTIC FEATURES TOWARD THE LATTER HALF OF NEXT WEEK. THE UPPER LEVEL LOW OVER THE PAC NW SLOWLY DROPS SOUTHEAST INTO THE CENTRAL ROCKIES WITH BROAD ANTICYCLONIC FLOW HOLDING STRONG OVER THE EASTERN CONUS. THIS WILL KEEP CONDITIONS FAVORABLE FOR MORE UNSETTLED WEATHER OVER THE CENTRAL PLAINS INCLUDING THE POTENTIAL FOR SEVERE WEATHER LATE IN THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1249 PM CDT SAT MAY 2 2015 THUNDERSTORM CHANCES HEADLINE THE AVIATION DISCUSSION...WITH TWO POSSIBLE...ALBEIT SLIGHT...CHANCES OF STORMS IMPACTING PORTIONS OF THE SANDHILLS REGION. THE FIRST CHANCE COMES LATE AFTERNOON AND INTO THE EVENING HOURS TONIGHT WHEN A SFC TROUGH ADVANCES EAST ACROSS THE SANDHILLS. THE 02.12Z NAM AND LATEST HRRR SEEM TO BE A GOOD COMPROMISE IN THAT STORMS SHOULD FORM ACROSS THE HEART OF THE SANDHILLS AND POSSIBLY ACROSS SW NEBRASKA. THE SECOND CHANCE COMES LATE IN THE FORECAST PERIOD SUNDAY MORNING...WHERE NORTH CENTRAL NEBRASKA IS FAVORED FOR STORM DEVELOPMENT. BOTH INSTANCES STORMS WILL BE ISOLATED TO SCATTERED AT BEST...SO CONFIDENCE IN STORMS IMPACTING EITHER KVTN OR KLBF IS LOW...MAY NEED UPDATES. IF A STORM DOES IMPACT A TERMINAL...GUSTY ERRATIC WIND AND SMALL HAIL WOULD BE POSSIBLE. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...POWER SHORT TERM...POWER LONG TERM...MARTIN AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1156 PM CDT FRI MAY 1 2015 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 242 PM CDT FRI MAY 1 2015 WEAK HIGH PRESSURE OVERHEAD WILL PIVOT MOISTURE NORTHWARD THIS EVENING. THE RAP AND HRRR SUGGEST WEAKLY ORGANIZED DISCRETE SHOWER AND THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON AND THIS EVENING. OTHER THAN GUSTY OUTFLOW WINDS...NO SIGNIFICANT WEATHER IS EXPECTED AND NO STORMS SHOULD REACH SEVERE LIMITS. A WARM FRONT WILL LIFT NORTH AS THE HIGH MOVES EAST LATER THIS EVENING. DEW POINTS SHOULD INCREASE TO AROUND 50F BY MID SATURDAY MORNING. THE NAM CONTINUES TO ADVERTISE A FAIRLY ROBUST DRYLINE SURGE SATURDAY AFTN FOCUSED ALONG HIGHWAY 20 WEST OF VALENTINE. DESTABILIZATION IS POSSIBLE ACROSS PINE RIDGE AND THE WRN SANDHILLS SOUTH THROUGH IMPERIAL AROUND 21Z. THE NAM DID SHOW ABOUT 20 TO 30 J/KG OF INHIBITION SO POPS ARE ISOLATED. MLCAPE NEAR 1500 J/KG AND BULK SHEAR TO 450 MB OF 30 TO 35 KT COULD SUPPORT AN ISOLATED STRONG OR SEVERE STORM DURING THE PEAK HEATING PERIOD. THE BULK RICHARDSON NUMBER IS CLOSE TO 50 AT THIS TIME AND SHEAR PROFILES LOOK SMOOTHLY CURVED. LOWS TONIGHT FALL TO THE UPPER 40S TO AROUND 50. HIGHS SATURDAY RISE INTO THE LOW TO MID 80S WITH MIXING HEIGHTS NEAR 700 MB. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 242 PM CDT FRI MAY 1 2015 A TRAJECTORY FROM THE PACIFIC SOUTHWEST CONTINUES SATURDAY NIGHT WHILE A TRAJECTORY FROM THE TEXAS GULF COAST CROSSES CENTRAL AND EASTERN NEBRASKA. THE PACIFIC MOISTURE WILL THUS BE IN PLACE WHEN A SURFACE FRONT COMES THROUGH SUNDAY MORNING. THE TIMING OF THE FRONT IS NOT REAL FAVORABLE FOR THUNDERSTORMS. HOWEVER...THE LIFT SHOULD BE SUFFICIENT TO TRIGGER ISOLATED CONVECTION BY SUNDAY EVENING WITH IT CONTINUING SUNDAY NIGHT AND MONDAY IN CENTRAL AND SOUTHWEST NEBRASKA. WITH THE FRONT BECOMING STATIONARY ACROSS CENTRAL KANSAS...SOME UPGLIDE WILL CONTINUE INTO MONDAY AFTERNOON AND EVENING. THIS CAN BE SEEN WITH THE PRESSURE LEVELS AND MOISTURE TRANSPORT VECTORS OVER CENTRAL...SOUTH CENTRAL AND SOUTHWEST NEBRASKA ON THE 300K AND 305K SURFACES. THE INSTABILITY...AT ABOUT 0C FOR THE 800MB BASED LIFTED INDEX...IS EXPECTED TO BE MARGINAL. AS A RESULT...ONLY A FEW EMBEDDED THUNDERSTORMS ARE EXPECTED IN AN AREA OF GENERAL RAIN OR SHOWERS. WITH PRECIPITABLE WATER EXCEEDING 0.7 INCH...SIGNIFICANT PRECIPITATION TOTALS CAN BE EXPECTED ALONG A BROKEN BOW-NORTH PLATTE-IMPERIAL LINE AND SOUTH WITH AMOUNTS DROPPING OFF SHARPLY NORTH OF THAT LINE. AS THE ACTIVE UPPER PATTERN CONTINUES...ANOTHER NEGATIVELY TILTED TROUGH PIVOTS ACROSS THE NORTHERN PLAINS. AHEAD OF THE SYSTEM...A GOOD MOISTURE TRAJECTORY CONTINUES TUESDAY NIGHT AND WEDNESDAY FROM THE TEXAS GULF COAST INTO NEBRASKA AND THE DAKOTAS. AS THE CYCLONE MAKES ITS WAY NORTHWARD...WARM ADVECTION ALOFT WILL CONTINUE BRINGING WIDESPREAD RAINFALL TO WESTERN NEBRASKA. BY EARLY THURSDAY...THE DRY INTRUSION OVERTAKES THE CYCLONE AND BRINGS AN END TO THE PRECIPITATION IN CENTRAL AND WESTERN NEBRASKA. THERE IS SIGNIFICANT DISAGREEMENT BETWEEN THE 00Z ECMWF AND THE 12Z GFS40 WITH THIS SYSTEM...SO CONFIDENCE IS NOT HIGH IN THE SOLUTIONS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1155 PM CDT FRI MAY 1 2015 VFR CONDITIONS FOR THE KLBF AND KVTN TERMINALS THE NEXT 24 HRS. ISOLATED THUNDERSTORMS NORTH OF THE KLBF TERMINAL ATTM SHOULD REAMIN OUTSIDE THE VICINITY THROUGH 08Z. OTHERWISE SKIES TO BECOME MOSTLY CLEAR OVERNIGHT. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...SPRINGER AVIATION...ROBERG
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1032 AM EDT SAT MAY 2 2015 .SYNOPSIS... HIGH PRESSURE WILL PROVIDE AN IDEAL SPRING WEEKEND WITH PLENTY OF SUNSHINE AND WARM TEMPERATURES AWAY FROM THE IMMEDIATE LAKESHORES. A COLD FRONT WILL CROSS THE AREA LATE MONDAY THROUGH TUESDAY AND BRING THE NEXT CHANCE OF RAIN AND POSSIBLY A FEW THUNDERSTORMS. TEMPERATURES WILL ONLY COOL FOR ONE DAY BEHIND THE COLD FRONT WITH PLENTY OF WARMTH RETURNING FOR THE SECOND HALF OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... IR SATELLITE IMAGERY SHOWS PATCHY HIGH CLOUDS EXTENDING FROM OHIO INTO THE LOWER LAKES. THESE WILL CONTINUE TO MOVE ACROSS THE REGION TODAY BUT WILL NOT BE THICK ENOUGH TO HAVE MUCH OF AN IMPACT ON TEMPERATURES. ONLY VERY MINOR CHANGES FOR THE FORECAST UPDATE. WILL BLEND IN THE HRRR TO FINE TUNE LAKE-BREEZES AND UPDATE SKY COVER BASED ON LATEST SATELLITE TRENDS. HIGH PRESSURE SURFACE AND ALOFT WILL BUILD INTO THE OHIO VALLEY AND GREAT LAKES TODAY AND PROVIDE A CONTINUATION OF THE VERY PLEASANT SPRING WEATHER. 850MB TEMPS OF AROUND +7C WILL SUPPORT HIGHS IN THE LOWER 70S AT LOWER ELEVATIONS INLAND FROM THE LAKES... WITH UPPER 60S ON THE HILLS. SOUTHWEST GRADIENT ONSHORE FLOW WILL KEEP AREAS EAST AND NORTHEAST OF LAKES ERIE AND ONTARIO COOLER... INCLUDING THE BUFFALO AND WATERTOWN AREAS. STRONG DIFFERENTIAL HEATING SHOULD ALLOW SOME SEMBLANCE OF A LAKE BREEZE TO DEVELOP ALONG THE SOUTH SHORE OF LAKE ONTARIO AND TURN THE SURFACE WINDS MORE NORTHWEST DURING THE AFTERNOON...COOLING THAT LAKESHORE AS WELL. TONIGHT HIGH PRESSURE WILL REMAIN IN PLACE FROM THE OHIO VALLEY TO THE MID ATLANTIC. A WEAK MID LEVEL SHORTWAVE WILL ROUND THE TOP OF THE RIDGE AND CROSS SOUTHERN ONTARIO AND NORTHERN NY. THIS MAY BRING A FEW PATCHY CLOUDS TO THE NORTH COUNTRY...BUT OTHERWISE MAINLY CLEAR SKIES WILL CONTINUE FOR THE REST OF THE AREA. EXPECT LOWS IN THE MID TO UPPER 40S ON THE LAKE PLAINS...WITH LOWER 40S AND EVEN UPPER 30S IN THE COOLER SOUTHERN TIER VALLEYS AND TUG HILL REGION. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... NO CHANGES MADE. SHORTWAVE UPPER-LEVEL RIDGING BUILDS ACROSS THE FORECAST AREA ON SUNDAY...WITH A SURFACE HIGH SLIDING OFF THE MID ATLANTIC COAST. THE RISING HEIGHTS ACROSS WESTERN NEW YORK WILL PUSH 850 MB TEMPERATURES TO AROUND +8C BY SUNDAY AFTERNOON. WITH THE SURFACE HIGH LOCATED SE OF THE AREA...WINDS WILL TURN TOWARD TO THE SOUTHWEST. SOUTHWEST WINDS WILL FAVOR DOWNSLOPE FLOW IN THE GENESEE VALLEY AND NORTHEAST OF THE TUG HILL REGION. THIS WILL ALLOW FOR THE WARMEST TEMPERATURES READING PUSHING CLOSE TO 80 IN THESE REGIONS. ELSEWHERE...MID 70S WILL BE COMMON. UNFORTUNATELY FOR THE BUFFALO AND WATERTOWN METRO AREAS...A SOUTHWEST FLOW MEANS LAKE BREEZES WILL KEEP THE IMMEDIATE SHORELINE THE COOLEST / WITH TEMPS IN THE 50S/ WITH STEADILY INCREASING TEMPERATURES INLAND. SKIES SHOULD BE MAINLY CLEAR...WITH THE EXCEPTION OF SOME AFTERNOON CUMULUS DEVELOPING OVER THE ALLEGHENY PLATEAU. THESE CU COULD BECOME DEVELOPED ENOUGH TO SUPPORT A LIGHT SPRINKLE OR SHOWER...BUT GIVEN RISING HEIGHTS AND DRY LOW-LEVELS WILL ONLY GIVE THIS A SLIGHT CHANCE. SUNDAY NIGHT WILL BE VERY MILD WITH LIGHT SOUTHERLY WINDS AND MOONLIT SKIES. TEMPERATURES WILL REMAIN IN THE 50S FOR MOST LOCATIONS. THE EXCEPTION WILL BE ANY INTERIOR VALLEYS WHERE THE WINDS CAN GO CALM...BUT EVEN THEN TEMPERATURES WILL ONLY LIKELY DIP INTO THE 40S. ON MONDAY...AN APPROACHING SHORTWAVE OVER THE UPPER GREAT LAKES...WILL INCREASE THE SOUTHWESTERLY FLOW ACROSS WESTERN AND CENTRAL NEW YORK. WINDS WILL PICK UP AND BECOME GUSTY BY MONDAY AFTERNOON AHEAD OF THE ASSOCIATED COLD FRONT MOVING IN FROM THE WEST. WINDS WILL LIKELY BE STRONGEST ACROSS THE NIAGARA FRONTIER AND INTO THE SAINT LAWRENCE RIVER VALLEY...WITH WIND GUSTS 30 TO 35 MPH LIKELY BY MONDAY AFTERNOON. THE COMBINATION OF THE THERMAL RIDGE FINALLY CROSSING THE FORECAST AREA AHEAD OF THE FRONT AND THE INCREASE SOUTHWESTERLY WINDS WILL PROMOTE AND EVEN WARMER DAY THAN SUNDAY. LOCATION ALONG THE GENESEE VALLEY SHOULD EASILY PUSH INTO THE LOWER 80S WITH THE STRONG DOWNSLOPE FLOW. ELSEWHERE MOST LOCATIONS WILL EASILY IN THE MID 70S. THE SAME EXCEPTIONS APPLY FOR BUFFALO AND WATERTOWN AS ON SUNDAY...WHERE THE SOUTHWEST FLOW OFF THE LAKE WILL KEEP THE METRO AREAS MUCH COOLER. BY LATE MONDAY...SCATTERED RAIN SHOWERS AND THUNDERSTORMS WILL APPROACH THE AREA FROM THE WEST ALONG THE COLD FRONT. WITH THE SHORTWAVE TROUGH PASSING WELL TO THE NORTH...DONT EXPECT A STRONG PUSH OF PRECIPITATION WITH THE FRONT...BUT WILL BE ENOUGH TO HELP FOCUS SCATTERED SHOWERS AND THUNDERSTORMS. THE OTHER CONSEQUENCE OF THE SHORTWAVE DEPARTING TO THE NORTH IS THAT THE FRONT BOUNDARY WILL SAG ACROSS THE FORECAST AREA MONDAY NIGHT AND BECOME STALLED ALMOST WEST-EAST ACROSS NEW YORK STATE. WITH FRONTOGENSIS AND SOME LIGHT ISENTROPIC ASCENT OVER THE BOUNDARY BEING THE ONLY FORCING MECHANISM...EXPECT FAIRLY SCATTERED / DISORGANIZED SHOWERS AND POSSIBLY SOME RUMBLES OF THUNDER TO LINGER MONDAY NIGHT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... THE AFOREMENTIONED BAROCLINIC ZONE WILL BE STALLED ACROSS OR JUST SOUTH OF THE FORECAST AREA BY TUESDAY MORNING. THIS BOUNDARY WILL SLOWLY CONTINUE TO SHIFT SOUTH THROUGH THE DAY. LIGHT NORTHERLY FLOW IN PLACE ON BOTH THE 00Z GFS AND 00Z ECMWF DEPICTING THE COLD FRONT TO REMAIN SOUTH OF THE REGION BY MIDDAY. HIGHS WILL REMAIN SLIGHTLY BELOW NORMAL WITH AFTERNOON TEMPERATURES ONLY IN THE LOWER 60S. SKIES WILL CLEAR OUT TUESDAY NIGHT. THE REMAINDER OF THE WORK WEEK WILL LIKELY REMAIN DRY AS ANOTHER RIDGE OF HIGH PRESSURE FROM SOUTHERN CANADA BECOMES ESTABLISHED OVER THE MIDWEST AND EASTERN GREAT LAKES REGION. TEMPERATURES WILL GRADUALLY WARM THROUGH THE PERIOD WITH HIGHS WEDNESDAY AROUND 70...INCREASING TO THE MID 70S TO LOWER 80S BY THE END OF THE WEEK. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... VFR WILL PREVAIL FOR THE 15Z TAF CYCLE. AN AREA OF THIN CIRRUS LEVEL CLOUDINESS WILL CROSS THE REGION FROM WEST TO EAST TODAY...AND SOME SCT DIURNAL CUMULUS MAY DEVELOP BY AFTERNOON ACROSS THE HIGHER TERRAIN WELL INLAND FROM THE LAKES...NEITHER OF WHICH WILL HAVE ANY IMPACT ON AVIATION. A FEW MORE MID LEVEL CLOUDS BEGIN TO INCREASE LATER TONIGHT. OUTLOOK... SUNDAY AND MONDAY...VFR. MONDAY NIGHT AND TUESDAY...A CHANCE OF SHOWERS AND THUNDERSTORMS AND LOCAL MVFR. WOODENEST...VFR. && .MARINE... HIGH PRESSURE WILL SLOWLY CROSS THE LOWER LAKES AND OHIO VALLEY THIS WEEKEND AND PROVIDE RELATIVELY LIGHT WINDS AND WAVE ACTION. SOUTHWEST WINDS WILL INCREASE SOME ON MONDAY AHEAD OF A COLD FRONT...ALTHOUGH THE COLD LAKE WATERS WILL STABILIZE THE BOUNDARY LAYER OVER THE LAKES AND KEEP WINDS LIGHTER IN THE MARINE ENVIRONMENT THAN OVER THE SURROUNDING LAND. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...HITCHCOCK NEAR TERM...APFFEL/HITCHCOCK SHORT TERM...CHURCH/HIBBERT LONG TERM...CHURCH AVIATION...APFFEL/HITCHCOCK MARINE...APFFEL/HITCHCOCK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1159 PM CDT FRI MAY 1 2015 .UPDATE... ISSUED AT 1159 PM CDT FRI MAY 1 2015 LATEST REGIONAL RADAR AND BOWMAN RADAR SHOWS SOME MID LEVEL RETURNS OVER MILES CITY. THE HRRR 1KM SLICE AND COMPOSITE REFLECTIVITY PICKS UP ON THIS AREA AND TRIES TO DEVELOP AN ISOLATED SHOWER OR TWO THROUGH 10Z ACROSS THE SOUTHWEST. CLOUD BASES APPEAR AROUND 15KFT CURRENTLY...AND WITH THE FAIRLY QUICK SPEED IN THE ECHOES AND MINIMAL AREAL COVERAGE...AT BEST A SPRINKLE OR BRIEF WIND GUST MAY OCCUR. OTHERWISE TEMPERATURES COOLING INTO THE MID 40S AT DICKINSON AND GLEN ULLIN...SO HAVE ADJUSTED HOURLY TEMPS DOWN A BIT QUICKER. OVERNIGHT LOWS ALREADY HAD THEM IN THE LOWER 40S AND WITH PASSING CLOUDS OVERNIGHT THIS REMAINS ON TRACK. MAIN CONCERN WILL BE FIRE WEATHER SATURDAY AND WILL LOOK MORE CLOSELY AT THIS IN THE NEXT UPDATE. UPDATE ISSUED AT 924 PM CDT FRI MAY 1 2015 THE FORECAST FOR THE OVERNIGHT REMAINS ON TRACK...WITH A RELATIVELY MILD NIGHT EXPECTED WITH LOWS IN THE MID TO UPPER 40S WITH LIGHT SOUTHERLY FLOW AHEAD OF THE PRE-FRONTAL TROUGH ACROSS EASTERN MONTANA. UPDATE ISSUED AT 714 PM CDT FRI MAY 1 2015 QUICK UPDATE TO EXPIRE THE RED FLAG WARNING ON TIME. NO OTHER CHANGES NEEDED OTHER THAN TO BLEND TO OBSERVED TRENDS TROUGH 00 UTC. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 255 PM CDT FRI MAY 1 2015 CURRENT SURFACE ANALYSIS PLACES LOW OVER SOUTHERN ALBERTA WITH WARM SOUTHWESTERLY FLOW OVER OUR AREA. UPPER LEVEL ANALYSIS PLACES FLAT RIDGE OVER THE ROCKIES INTO THE PLAINS WITH WESTERLY FLOW OVER THE NORTHERN PLAINS BRINGING QUIET WEATHER TO THE AREA. FOR THE REST OF THIS AFTERNOON INTO TONIGHT...BREEZY CONDITIONS OVER THE WEST AND NORTH CENTRAL WILL SUBSIDE THIS EVENING. OTHERWISE...QUIET WEATHER EXPECTED. ON SATURDAY...SURFACE LOW SLIDES EAST ACROSS SOUTHERN SASKATCHEWAN/MANITOBA...WHILE A COLD FRONT PUSHES ITS WAY INTO WESTERN/CENTRAL NORTH DAKOTA. EXPECT GUSTY WINDS TO DEVELOP AHEAD OF AND ALONG THE FRONT IN REGION OF STRONG MIXING/STEEP LAPSE RATES. GUSTY WINDS WILL ALSO CONTINUE AFTER FRONTAL PASSAGE. A FEW THUNDERSTORMS MAY DEVELOP OVER SOUTH CENTRAL NORTH DAKOTA INTO THE JAMES RIVER VALLEY WHERE MODEST INSTABILITY IS NOTED...THOUGH NOT MUCH IN THE WAY OF PRECIPITATION EXPECTED GIVEN THE DRY LOW LEVELS THOUGH THIS MAY BE CONDUCIVE TO STORMS POSSIBLY DEVELOPING STRONG WIND GUSTS. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 255 PM CDT FRI MAY 1 2015 THE LONG TERM FORECAST IS DOMINATED BY A WEST COAST TROUGH THAT IS FORECAST TO BECOME PHASED WITH THE EASTERN PACIFIC CUT OFF LOW NEAR 160W IN CURRENT SATELLITE IMAGERY. REMAINING SHORTWAVE ENERGY FROM THE CUT OFF LOW IS THEN FORECAST TO EJECT INTO THE NORTHERN PLAINS BY SATURDAY. MODELS/ENSEMBLES HAVE BEEN FAIRLY CONSISTENT WITH THIS FEATURE OVER THE PAST COUPLE DAYS...AND THE STRONG MID LEVEL DYNAMICS ASSOCIATED WITH THE WAVE SUPPORT SOME OF THE HIGHER PRECIPITATION CHANCES SEEN IN THE REGION FOR SOME TIME. AT THIS POINT...THERE IS NO INDICATION OF WHETHER STORMS WILL BECOME SEVERE...BUT THAT IS CERTAINLY A POSSIBILITY AS SUCH DYNAMICALLY FORCED SYSTEMS ARE TYPICALLY ACCOMPANIED BY AT LEAST SOME SEVERE WEATHER DURING SPRING MONTHS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1159 PM CDT FRI MAY 1 2015 VFR CIGS/VSBYS NEXT 24HR. A COLD FRONT WILL MOVE INTO WESTERN NORTH DAKOTA BETWEEN 12Z-15Z SATURDAY...THEN TRANSLATE INTO CENTRAL NORTH DAKOTA SATURDAY AFTERNOON...21Z-00Z. EXPECTED A WIND SHIFT FROM SOUTHWEST TO WEST/NORTHWEST. A VCTS WILL BE MENTIONED AT KMOT AND KJMS SATURDAY AFTERNOON. && .FIRE WEATHER... ISSUED AT 255 PM CDT FRI MAY 1 2015 CRITICAL FIRE WEATHER CONDITIONS WILL CONTINUE OVER MANY PARTS OF WESTERN AND NORTH CENTRAL NORTH DAKOTA THROUGH THIS AFTERNOON. ON SATURDAY...CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE ACROSS ALL OF NORTH DAKOTA WITH LOW RELATIVE HUMIDITY VALUES AND GUSTY SOUTHWEST WINDS. WINDS WILL START TO SWITCH TOWARDS THE NORTHWEST IN THE WEST AND CENTRAL AS A COLD FRONT MOVES INTO THE AREA. ISOLATED THUNDERSTORMS WILL BE POSSIBLE ACROSS PORTIONS OF THE AREA. LOW RELATIVE HUMIDITY VALUES ARE EXPECTED FOR THE BEGINNING OF NEXT WEEK WITH OCCASIONAL BREEZY CONDITIONS. CONDITIONS WILL BE MONITORED TO SEE IF FURTHER HEADLINES WILL BE NEEDED. DAILY CHANCES FOR WETTING RAINS WILL COME TOWARDS THE MIDDLE OF NEXT WEEK. && .BIS WATCHES/WARNINGS/ADVISORIES... FIRE WEATHER WATCH FROM 11 AM CDT /10 AM MDT/ SATURDAY THROUGH SATURDAY EVENING FOR NDZ001>005-009>013-017>023-025-031>037- 040>048-050-051. && $$ UPDATE...KS SHORT TERM...JJS LONG TERM...SCHECK AVIATION...KS FIRE WEATHER...JJS
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
631 PM CDT SUN MAY 3 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 323 PM CDT SUN MAY 3 2015 HAVE SEEN SCATTERED SPRINKLES/LIGHT SHOWERS DEVELOP OVER THE WESTERN CWA ALONG ELEVATED BOUNDARY AHEAD OF THE MID LEVEL WAVE. UPDATED GRIDS TO PROGRESS THIS ACTIVITY EASTWARD ACROSS THE AREA THIS AFTERNOON...WITH CONVECTIVE POTENTIAL GRADUALLY INCREASING ACROSS SOUTHEAST HALF OF THE FORECAST AREA AS THE ELEVATED FRONT WORKS INTO MORE UNSTABLE AIR MASS. SURFACE BASED STORMS MAY BE TOUGHER TO COME BY...AS SURFACE CONVERGENCE SOMEWHAT ILL-DEFINED WITH BROAD AREA OF WEAK/VARIABLE FLOW AHEAD OF THE BOUNDARY... LOCATED SOUTH OF KYKN-KFSD-KTKC LINE AT 18Z. ISOLATED SEVERE STILL APPEAR POSSIBLE ACROSS THE SOUTHEAST...WITH RECENT HRRR MODEL RUNS INDICATING A POTENTIAL FOR WIND THREAT ASSOCIATED WITH COLD POOL AHEAD OF ELEVATED STORMS AS THEY TRACK ACROSS EXTREME SOUTHEAST SD/NORTHWEST IA. NOT WHOLLY CONVINCED THIS WILL PAN OUT...BUT DOES NOT SEEM ENTIRELY UNREASONABLE GIVEN HIGHER-BASED STORMS WITH DRIER AIR UNDERCUTTING BEHIND SURFACE BOUNDARY...SO WILL DEFINITELY NEED TO MONITOR THROUGH THE LATE AFTERNOON/EARLY EVENING. OVERALL CONVECTIVE CHANCES SHOULD WANE AFTER 02Z-03Z AS THE WAVE PASSES BY...WITH OVERNIGHT HOURS INTO EARLY MONDAY MORNING EXPECTED TO BE DRY ACROSS THE AREA. INCREASING ISENTROPIC LIFT AHEAD OF BROAD WAVE SHOULD BEGIN TO SPREAD PRECIP BACK INTO SOUTHERN PARTS OF THE AREA MONDAY AFTERNOON...WITH MAIN QUESTION BEING HOW QUICKLY IT EXPANDS TO THE NORTHEAST THE DRY LOW LEVEL EAST-NORTHEAST FLOW FIRMLY IN PLACE. WILL HOLD GENERALLY SOUTHWEST OF KHON-KFSD-KSPW LINE...SUPPORTED BY GREATER MODEL CONSENSUS OF NAM/ECMWF/GEM. MONDAY SHOULD BE A COOLER DAY...WITH THICKER CLOUDS HOLDING TEMPS IN THE 60S THROUGH THE MISSOURI VALLEY...WITH LOWER 70S MORE PREVALENT TO THE NORTHEAST. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 323 PM CDT SUN MAY 3 2015 ON MONDAY NIGHT AND TUESDAY A WARM FRONT BEGINS TO LIFT NORTHWARD THROUGH NEBRASKA...WITH INCREASING MIDLEVEL THETA E ADVECTION ACROSS OUR AREA DURING THE PERIOD. WITH THIS WILL HAVE INCREASING PRECIPITATION CHANCES...ESPECIALLY IN OUR SOUTH AND EAST. INSTABILITY IS NOT ESPECIALLY IMPRESSIVE SO STAYED MAINLY WITH ISOLATED THUNDER...ALTHOUGH IT DOES LOOK TO BE A LITTLE MORE UNSTABLE IN OUR SOUTH ON TUESDAY AFTERNOON. HIGHS ON TUESDAY WILL MAINLY BE UPPER 60S TO LOWER 70S...THOUGH AREAS THROUGH THE LOWER MO RIVER VALLEY MAY APPROACH 80. ON WEDNESDAY A MORE SIGNIFICANT VORT LOBE BEGINS TO LIFT OUT OF THE WESTERN CONUS UPPER LEVEL TROUGH AND INTO THE CENTRAL AND NORTHERN PLAINS. THIS WILL MOSTLY LIKELY BRING MORE SIGNIFICANT PRECIPITATION TO THE AREA FOR LATER ON WEDNESDAY INTO WEDNESDAY NIGHT. WHILE IT WILL BE FAIRLY UNSTABLE ON WEDNESDAY...SHEAR IS RATHER UNIMPRESSIVE...BUT THERE WILL MOST LIKELY BE THUNDERSTORMS AROUND. HIGHS AGAIN WILL BE RUNNING LOWER TO MID 70S. RAIN CHANCES THEN CONTINUE INTO THURSDAY WHEN A SURFACE FRONTAL BOUNDARY SWINGS ACROSS THE AREA AS THE UPPER LEVEL SHORTWAVE PULLS OFF INTO THE WESTERN GREAT LAKES REGION. MAY FINALLY BEGIN TO DRY OUT BY THURSDAY NIGHT AND FRIDAY AS HIGH PRESSURE BEGINS TO BUILD BACK INTO THE REGION BEHIND THE EXITING SYSTEM. SLIGHTLY COOLER AIR FILTERS INTO THE AREA FOR FRIDAY...THOUGH STILL LOOKING AT HIGHS MID 60S TO LOWER 70S. RAIN DOES LOOK TO RETURN BY NEXT WEEKEND HOWEVER AS ANOTHER UPPER LEVEL LOW LIFTS OUT OF THE WESTERN CONUS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 631 PM CDT SUN MAY 3 2015 MAIN FOCUS IS CONVECTION THIS EVENING. FOR KHON...CONDITIONS EXPECTED TO BE VFR THROUGH 00Z TUE. FOR KFSD...ALSO EXPECTING VFR CONDITIONS THROUGH PERIOD WITH WINDS DROPPING OFF TO 10 TO 15 KTS AFTER 02Z. SMALL CONCERN THAT HIGH RES MODELS ARE SHOWING SOME CONVECTION DEVELOPING BETWEEN 03Z AND 06Z AND NAM/GFS SOUNDINGS DO SHOW INSTABILITY ABOVE 800 MB. AT THIS POINT...PROBABILITY IS TOO LOW TO INCLUDE IN TAF BUT WILL NEED TO MONITOR FOR STORMS LATER TONIGHT. FOR KSUX...IN GENERAL VFR CONDITIONS EXPECTED. THERE IS A CHANCE OF STORMS THIS EVENING ALTHOUGH NO EVIDENCE ON SATELLITE OR RADAR THAT STORMS ARE IMMINENT SO HAVE WILL NOT INCLUDE IN TAF AT THIS TIME. OTHERWISE...SIMILAR ISSUE TO KFSD IN THAT HI-RES MODELS MOVE THESE STORMS NEAR KSUX BETWEEN 05Z AND 09Z TONIGHT. AGAIN...PROBABILITY TOO LOW TO INCLUDE IN TAF. NEXT ROUND OF RAIN WILL BE APPROACHING KSUX AROUND 00Z. AT THIS POINT...BETTER CHANCES AFTER 00Z TUESDAY SO KEPT CONDITIONS VFR. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...JH LONG TERM...JM AVIATION...SCHUMACHER
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
135 PM EDT SAT MAY 2 2015 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE REGION TODAY AND INTO MUCH OF THE EARLY WEEK. OUR NEXT BEST CHANCE OF PRECIPITATION WILL COME DURING THE MIDDLE OF NEXT WEEK WHEN A BACKDOOR COLD FRONT APPROACHES OUR AREA. && .NEAR TERM /THROUGH TONIGHT/... AS OF 930 AM EDT SATURDAY... OVERALL A NICE DAY TO START OFF THE WEEKEND. THE DENSE FOG ADVISORY EXPIRED AT 9AM. THERE ARE STILL SOME ISOLATED POCKETS OF RIVER VALLEY FOG ACROSS THE MOUNTAIN EMPIRE...HOWEVER THAT SHOULD BURN OFF WITHIN THE NEXT HOUR OR SO. MOST OF THE REGION CAN EXPECT A DRY AND PARTLY SUNNY DAY...ALTHOUGH THERE IS THE SLIGHT CHANCE FOR AN ISOLATED SHOWER FOR A BRIEF WINDOW THIS AFTERNOON EAST OF THE BLUE RIDGE. HRRR CONTINUES TO SHOW WEAK INSTABILITY OF 100-300 MU CAPE EARLY THIS AFTERNOON AND WANTS TO POP UP A FEW SHOWERS...THEREFORE ADDED SLIGHT CHANCE POPS OUT EAST. AS OF 730 AM EDT SATURDAY... DENSE FOG ADVISORY FOR A FEW COUNTIES IN THE NORTH EXPIRES AT 13Z. SURFACE AND UPPER LOW WILL CONTINUE TO MOVE FURTHER OUT INTO THE ATLANTIC OCEAN TODAY WITH HIGH PRESSURE AND DRIER AIR OVER THE OHIO VALLEY BUILDING EASTWARD. TODAY WILL BE PARTLY TO MOSTLY SUNNY AND MILDER WITH HIGHS ACROSS THE MOUNTAINS RANGING FROM THE MID 60S TO NEAR 70 DEGREES...WITH LOW TO MID 70S ACROSS THE PIEDMONT. CONTINUED DRY AND TRANQUIL OVERNIGHT WITH LOWS NEAR SEASONAL NORMALS IN THE 40S. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 315 PM EDT FRIDAY... WEAK HIGH PRESSURE WILL SLIDE ACROSS THE REGION SUNDAY. AS THIS HIGH MOVES TO THE COAST...LIGHT SOUTHERLY FLOW WILL BRING WARM MOIST AIR INTO THE REGION. WITH SOME WEAKNESS ALOFT FROM AN UPPER LEVEL TROUGH...ISOLATED SHOWERS ARE POSSIBLE OVER THE NORTH CAROLINA HIGH COUNTRY LATE SUNDAY AFTERNOON. ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE MONDAY AFTERNOON AS A COOL POOL ALOFT DRIFTS OVER THE REGION. TEMPERATURES WILL RUN WARMER THAN NORMAL SUNDAY AND MONDAY WITH AREAS SEEING SHOWERS PEAKING IN THE UPPER 60S AND LOCATIONS REMAIN DRY WARMING INTO THE 70S. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 125 PM EDT FRIDAY... LONG WAVE PATTERN ADVERTISED BY MODELS SHOWED TROFING IN THE WESTERN UNITED STATES AND A BROAD SOUTHEAST U.S. RIDGE. A SURFACE COLD FRONT THE THE NORTHERN STREAM WILL BE OVER THE GREAT LAKES ON MONDAY AND WILL PUSH SOUTH AS A BACKDOOR FRONT OVER THE MID ATLANTIC REGION TUESDAY AND WEDNESDAY. QUESTIONABLE HOW FAR SOUTH THIS BOUNDARY GETS HEADING INTO A LARGE RIDGE OVER THE SOUTHEAST. BEST PROBABILITY OF PRECIPITATION WILL BE IN THE VICINITY OF THIS BOUNDARY. OTHERWISE THE CHANCE WILL BE LIMITED TO AIRMASS TYPE THUNDERSTORMS...MAINLY IN THE MOUNTAINS EACH AFTERNOON AND EVENING. MAXIMUM/MINIMUM TEMPERATURES WILL REMAIN 5 TO 15 DEGREES ABOVE NORMAL TUESDAY THROUGH FRIDAY. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 130 PM EDT SATURDAY... HIGH PRESSURE WAS OVER THE TENNESSEE VALLEY THIS AFTERNOON. SATELLITE PICTURES SHOWED SCATTERED TO BROKEN VFR CUMULUS...MAINLY EAST OF THE BLUE RIDGE. CLOUD COVER WILL DIMINISH THIS EVENING ONCE THE SUN SETS. WINDS WILL BECOME LIGHT AND VARIABLE TONIGHT AS HIGH PRESSURE CROSSES THE AREA. EXPECT DEW POINTS ARE LOW ENOUGH TO LIMIT FORMATION OF FOG OVERNIGHT. THE MOST LIKELY LOCATION THAT MAY SEE SHALLOW GROUND FOG IS KLWB BUT CONFIDENCE WAS NOT HIGH ENOUGH TO ADD TO THE TAF AT THIS TIME. NOTE...THE VISIBILITY SENSOR AT THE ASOS AT KBLF CONTINUES TO BE OUT OF SERVICE. REPAIRS MAY NOT BE POSSIBLE UNTIL THE END OF MAY. WILL CONTINUE WITH AMD NOT SKED APPENDED TO THIS TAF. EXTENDED AVIATION DISCUSSION... OTHER THAN SOME PATCHY LATE NIGHT/EARLY MORNING RIVER VALLEY FOG IN THE TYPICAL LOCATIONS...VFR CONDITIONS ARE EXPECTED THROUGH MONDAY NIGHT. SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG THE SOUTHERN BLUE RIDGE ON TUESDAY...WHICH WOULD YIELD MVFR CONDITIONS. SHOWERS AND THUNDERSTORMS WILL BE MORE WIDESPREAD ON WEDNESDAY AND THURSDAY AS A BACK DOOR FRONT ENTERS THE REGION. HIGH PRESSURE ALOFT WILL LIMIT MUCH IN THE WAY OF ANY SYNOPTIC-SCALE FORCING THROUGH THE PERIOD. && .EQUIPMENT... AS OF 130 PM EDT SATURDAY... THE VISIBILITY SENSOR AT THE BLUEFIELD...KBLF...ASOS MAY ALTERNATE BETWEEN AVAILABLE AND UNAVAILABLE UNTIL FURTHER NOTICE. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS NEAR TERM...CF/PC SHORT TERM...RCS LONG TERM...AMS AVIATION...AMS/PC EQUIPMENT...DS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
946 AM EDT SAT MAY 2 2015 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE REGION TODAY AND INTO MUCH OF THE EARLY WEEK. OUR NEXT BEST CHANCE OF PRECIPITATION WILL COME DURING THE MIDDLE OF NEXT WEEK WHEN A BACKDOOR COLD FRONT APPROACHES OUR AREA. && .NEAR TERM /THROUGH TONIGHT/... AS OF 930 AM EDT SATURDAY... OVERALL A NICE DAY TO START OFF THE WEEKEND. THE DENSE FOG ADVISORY EXPIRED AT 9AM. THERE ARE STILL SOME ISOLATED POCKETS OF RIVER VALLEY FOG ACROSS THE MOUNTAIN EMPIRE...HOWEVER THAT SHOULD BURN OFF WITHIN THE NEXT HOUR OR SO. MOST OF THE REGION CAN EXPECT A DRY AND PARTLY SUNNY DAY...ALTHOUGH THERE IS THE SLIGHT CHANCE FOR AN ISOLATED SHOWER FOR A BRIEF WINDOW THIS AFTERNOON EAST OF THE BLUE RIDGE. HRRR CONTINUES TO SHOW WEAK INSTABILITY OF 100-300 MU CAPE EARLY THIS AFTERNOON AND WANTS TO POP UP A FEW SHOWERS...THEREFORE ADDED SLIGHT CHANCE POPS OUT EAST. AS OF 730 AM EDT SATURDAY... DENSE FOG ADVISORY FOR A FEW COUNTIES IN THE NORTH EXPIRES AT 13Z. SURFACE AND UPPER LOW WILL CONTINUE TO MOVE FURTHER OUT INTO THE ATLANTIC OCEAN TODAY WITH HIGH PRESSURE AND DRIER AIR OVER THE OHIO VALLEY BUILDING EASTWARD. TODAY WILL BE PARTLY TO MOSTLY SUNNY AND MILDER WITH HIGHS ACROSS THE MOUNTAINS RANGING FROM THE MID 60S TO NEAR 70 DEGREES...WITH LOW TO MID 70S ACROSS THE PIEDMONT. CONTINUED DRY AND TRANQUIL OVERNIGHT WITH LOWS NEAR SEASONAL NORMALS IN THE 40S. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 315 PM EDT FRIDAY... WEAK HIGH PRESSURE WILL SLIDE ACROSS THE REGION SUNDAY. AS THIS HIGH MOVES TO THE COAST...LIGHT SOUTHERLY FLOW WILL BRING WARM MOIST AIR INTO THE REGION. WITH SOME WEAKNESS ALOFT FROM AN UPPER LEVEL TROUGH...ISOLATED SHOWERS ARE POSSIBLE OVER THE NORTH CAROLINA HIGH COUNTRY LATE SUNDAY AFTERNOON. ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE MONDAY AFTERNOON AS A COOL POOL ALOFT DRIFTS OVER THE REGION. TEMPERATURES WILL RUN WARMER THAN NORMAL SUNDAY AND MONDAY WITH AREAS SEEING SHOWERS PEAKING IN THE UPPER 60S AND LOCATIONS REMAIN DRY WARMING INTO THE 70S. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 125 PM EDT FRIDAY... LONG WAVE PATTERN ADVERTISED BY MODELS SHOWED TROFING IN THE WESTERN UNITED STATES AND A BROAD SOUTHEAST U.S. RIDGE. A SURFACE COLD FRONT THE THE NORTHERN STREAM WILL BE OVER THE GREAT LAKES ON MONDAY AND WILL PUSH SOUTH AS A BACKDOOR FRONT OVER THE MID ATLANTIC REGION TUESDAY AND WEDNESDAY. QUESTIONABLE HOW FAR SOUTH THIS BOUNDARY GETS HEADING INTO A LARGE RIDGE OVER THE SOUTHEAST. BEST PROBABILITY OF PRECIPITATION WILL BE IN THE VICINITY OF THIS BOUNDARY. OTHERWISE THE CHANCE WILL BE LIMITED TO AIRMASS TYPE THUNDERSTORMS...MAINLY IN THE MOUNTAINS EACH AFTERNOON AND EVENING. MAXIMUM/MINIMUM TEMPERATURES WILL REMAIN 5 TO 15 DEGREES ABOVE NORMAL TUESDAY THROUGH FRIDAY. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... AS OF 735 AM EDT SATURDAY... PATCHY FOG POSSIBLE FOR AN HOUR OR TWO THIS MORNING BUT AFTER 13Z EXPECT VFR CONDITIONS AREA WIDE TODAY. WINDS LIGHT AND MOSTLY NW TODAY BECOMING CALM OR LIGHT VARIABLE THIS EVENING AND OVERNIGHT. NOTE...THE VISIBILITY SENSOR AT THE ASOS AT KBLF CONTINUES TO MALFUNCTION. WILL CONTINUE WITH AMD NOT SKED APPENDED TO ITS TAF. EXTENDED AVIATION DISCUSSION... OTHER THAN SOME PATCHY LATE NIGHT/EARLY MORNING RIVER VALLEY FOG IN THE TYPICAL LOCATIONS...VFR CONDITIONS ARE EXPECTED THROUGH MONDAY NIGHT. SCATTERED AFTERNOON SHOWERS COULD AFFECT THE MOUNTAINS TUE...BUT MORE LIKELY WED-THU AS A BACK DOOR FRONT DRIFTS TOWARD THE REGION. HIGH PRESSURE ALOFT WILL NOT PROVIDE MUCH IN THE WAY OF ANY SYNOPTIC-SCALE FORCING THROUGH THE PERIOD THOUGH. && .EQUIPMENT... AS OF 907 PM EDT FRIDAY... THE VISIBILITY SENSOR AT THE BLUEFIELD...KBLF...ASOS MAY ALTERNATE BETWEEN AVAILABLE AND UNAVAILABLE UNTIL SUCH TIME APPROPRIATE CORRECTIVE MEASURES CAN BE COMPLETED. THE NOAA WEATHER RADIO AT ROANOKE VIRGINIA...WXL60...WHICH BROADCASTS AT A FREQUENCY OF 162.475 MHZ...IS BACK ON THE AIR. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS NEAR TERM...CF/PC SHORT TERM...RCS LONG TERM...AMS AVIATION...DS/PC EQUIPMENT...DS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
147 AM EDT SAT MAY 2 2015 .SYNOPSIS... AN UPPER LEVEL LOW PRESSURE SYSTEM WILL PROGRESS EASTWARD...OUT OF THE REGION OVERNIGHT. HIGH PRESSURE WILL BUILD INTO THE REGION THIS WEEKEND AND BE POSITIONED ACROSS OUR REGION INTO MUCH OF NEXT WEEK. OUR NEXT BEST CHANCE OF PRECIPITATION WILL COME DURING THE MIDDLE OF NEXT WEEK WHEN A BACKDOOR COLD FRONT APPROACHES OUR AREA. && .NEAR TERM /THROUGH TODAY/... AS OF 908 PM EDT FRIDAY... UPPER LOW WILL DRIFT EAST INTO THE ATLANTIC OCEAN OVERNIGHT AND SATURDAY. A BROAD RIDGE OF HIGH PRESSURE WILL BUILD EAST FROM THE OHIO VALLEY FOR SATURDAY. KFCX WSR-88D AT 01Z SHOWED SOME ISOLATED CONVECTION DROPPING SOUTH ACROSS EASTERN PORTIONS OF FORECAST AREA. THIS EVENING 00Z RNK SOUNDING SHOWED THE DRIER AIR PUSHING AROUND 700 MB WITH A NORTHERLY FLOW AND PWAT AT 0.46 IN. THE NAM...HRRR...RNK WRFARW AND HIRESW-ARW SUPPORT THE MENTION OF ISOLATED SHOWERS TONIGHT UNTIL AROUND 06Z...MAINLY EAST OF THE BLUE RIDGE MOUNTAINS. PATCHES OF FOG WILL DEVELOP OVERNIGHT ESPECIALLY WHERE IT RAIN FRIDAY. LOW TEMPERATURES OVERNIGHT WILL RANGE FROM AROUND 40 DEGREES IN THE NORTHWEST MOUNTAINS TO THE MID TO UPPER 40S IN THE PIEDMONT. HAVE A GOOD NIGHT. AS OF 555 PM EDT FRIDAY... ADJUSTED TEMPERATURES DOWN IN RAIN COOLED LOCATIONS AND BLEND LAMP TEMPERATURES INTO THE OVERNIGHT. MODIFIED POPS AND WEATHER WITH LATEST WSR-88D TRENDS AND SHAPED POPS THIS EVENING INTO TONIGHT TOWARDS A BLEND OF THE HRRR AND THE RNK WRFARW. AS THE UPPER LOW PUSHES EAST...AREAL COVERAGE OF CONVECTION WILL DIMINISH AND EXIT THE REGION. PATCHES OF FOG WILL DEVELOP ESPECIALLY WHERE IT RAIN THIS AFTERNOON AND THIS EVENING AND CONTINUE INTO THE OVERNIGHT. HELD ON TO THE THE OVERNIGHT LOW TEMPERATURES FROM AROUND 40 DEGREES IN THE NORTHWEST MOUNTAINS TO THE UPPER 40S IN THE PIEDMONT. AS OF 300 PM EDT FRIDAY... AN AREA OF SHOWERS WITH A FEW THUNDERSTORMS CONTINUES TO EXPAND IN COVERAGE BETWEEN ROUGHLY HOT SPRINGS AND BLACKSBURG VA. THE PRECIPITATION WAS EXPANDING TOWARDS THE S-SW. HEADING INTO THIS EVENING...THE REGION OF PRECIPITATION WILL GRADUALLY MAKE PROGRESS EASTWARD...IN PACE WITH THE PROGRESSION OF THE RESPONSIBLE UPPER LEVEL LOW PRESSURE SYSTEM. COVERAGE WILL START TO DECREASE AT SUNSET...WITH THE LAST SHOWERS EXITING THE AREA OR DISSIPATING AROUND 11PM BETWEEN DANVILLE AND LYNCHBURG. CLOUD COVER WILL BE ON THE DECREASE THE REMAINDER OF THE NIGHT. PATCHY LIGHT RIVER VALLEY FOG WILL BE POSSIBLE...AND ALSO IN VALLEYS THAT RECEIVED PRECIPITATION THIS AFTERNOON OR EVENING. LOW TEMPERATURES WILL RANGE FROM AROUND 40 TO THE MID 40S ACROSS THE MOUNTAINS...WITH MID 40S TO UPPER 40S ACROSS THE PIEDMONT. ON SATURDAY...HIGH PRESSURE WILL START TO WORK ITS WAY INTO THE REGION FROM THE WEST. ONE LATE SHORTWAVE TROUGH ROUNDING THE BACKSIDE OF THE DEPARTING UPPER LOW IS EXPECTED TO MOVE SOUTH THROUGH CENTRAL VIRGINIA AND NORTH CAROLINA TOMORROW AFTERNOON. THIS FEATURE PASSING AT THE TIME OF PEAK HEATING MAY HELP TO GENERATE SOME ISOLATED SHOWERS...GENERALLY ALONG AND EAST OF A LEXINGTON VA TO REIDSVILLE NORTH CAROLINA LINE. THANKS TO BUILDING HEIGHTS AND LESS CLOUD COVER...ANTICIPATE A MILDER DAY ON SATURDAY AS COMPARED TO TODAY. HIGHS ACROSS THE MOUNTAINS WILL RANGE FROM THE MID 60S TO NEAR 70 DEGREES...WITH LOW TO MID 70S ACROSS THE PIEDMONT. && .SHORT TERM /TONIGHT THROUGH MONDAY/... AS OF 315 PM EDT FRIDAY... 500 MB HEIGHTS GRADUALLY RISE SATURDAY NIGHT AND SUNDAY AS THE PATTERN BECOMES MORE ZONAL. BUFKIT DATA FOR SUNDAY IN THE SOUTHWEST COUNTY WARNING AREA SHOWED A LARGE ENOUGH LOW LEVEL LAPSE RATE AND A LAYER OF MOISTURE THAT WOULD SUPPORT SHOWERS ISOLATED THUNDERSTORMS. HOWEVER...THERE WILL ONLY BE MINIMAL LIFT FROM ANY VORTICITY SO COVERAGE WILL BE CONFINED TO AREAS WITH THE BEST HEATING AND INSTABILITY. AIR MASS WARMS THROUGH THE PERIOD AND WILL BE CLOSE TO +10 TO +12 VALUES AT 850 MB BY THE END OF THE DAY ON MONDAY. THIS WILL PUT MAXIMUM TEMPERATURES JUST ABOVE NORMAL MONDAY. HIGH PRESSURE WILL BE OVER THE AREA SATURDAY NIGHT AND SUNDAY. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 125 PM EDT FRIDAY... LONG WAVE PATTERN ADVERTISED BY MODELS SHOWED TROFING IN THE WESTERN UNITED STATES AND A BROAD SOUTHEAST U.S. RIDGE. A SURFACE COLD FRONT THE THE NORTHERN STREAM WILL BE OVER THE GREAT LAKES ON MONDAY AND WILL PUSH SOUTH AS A BACKDOOR FRONT OVER THE MID ATLANTIC REGION TUESDAY AND WEDNESDAY. QUESTIONABLE HOW FAR SOUTH THIS BOUNDARY GETS HEADING INTO A LARGE RIDGE OVER THE SOUTHEAST. BEST PROBABILITY OF PRECIPITATION WILL BE IN THE VICINITY OF THIS BOUNDARY. OTHERWISE THE CHANCE WILL BE LIMITED TO AIRMASS TYPE THUNDERSTORMS...MAINLY IN THE MOUNTAINS EACH AFTERNOON AND EVENING. MAXIMUM/MINIMUM TEMPERATURES WILL REMAIN 5 TO 15 DEGREES ABOVE NORMAL TUESDAY THROUGH FRIDAY. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 135 AM EDT SATURDAY... GENERALLY IMPROVING FLT CONDITIONS WILL CONTINUE OVERNIGHT AS THE SURFACE/UPPER LOW CONTINUE TO MOVE EAST OF THE AREA. PSBL GROUND FOG IN SOME AREAS OVERNIGHT...BUT SO FAR VERY IT HAS BEEN PATCHY...WENT WITH MVFR FOR A PERIOD AT DAN/LWB/BCB AND IFR AT LYH WHERE IT SEEMS TO BE DEVELOPING EARLIER. AFTER 14Z SAT...EXPECT VFR CONDITIONS AREA WIDE. WINDS LIGHT AND MOSTLY NW THROUGH THE TAF VALID PERIOD ON THE BACK SIDE OF THE UPPER LOW...BUT SOME VARIABLE WINDS THIS EVENING. AT ANY RATE...SPEEDS MOSTLY 7KTS OR LESS THROUGH THE TAF VALID PERIOD. MEDIUM CONFIDENCE IN CIGS THROUGH THE TAF VALID PERIOD. MEDIUM CONFIDENCE IN VSBYS THROUGH 14Z...THEN HIGH CONFIDENCE IN VFR VSBYS AT ALL TAF SITES. MEDIUM CONFIDENCE IN WIND SPD/DIR THROUGH THE TAF VALID PERIOD. NOTE...THE VISIBILITY SENSOR AT THE ASOS AT KBLF CONTINUES TO MALFUNCTION. WILL CONTINUE WITH AMD NOT SKED APPENDED TO ITS TAF. EXTENDED AVIATION DISCUSSION... OTHER THAN SOME PATCHY LATE NIGHT/EARLY MORNING RIVER VALLEY FOG IN THE TYPICAL LOCATIONS...VFR CONDITIONS ARE EXPECTED THROUGH MONDAY NIGHT. SCATTERED AFTERNOON SHOWERS COULD AFFECT THE MOUNTAINS TUE...BUT MORE LIKELY WED-THU AS A BACK DOOR FRONT DRIFTS TOWARD THE REGION. HIGH PRESSURE ALOFT WILL NOT PROVIDE MUCH IN THE WAY OF ANY SYNOPTIC-SCALE FORCING THROUGH THE PERIOD THOUGH. && .EQUIPMENT... AS OF 907 PM EDT FRIDAY... THE VISIBILITY SENSOR AT THE BLUEFIELD...KBLF...ASOS MAY ALTERNATE BETWEEN AVAILABLE AND UNAVAILABLE UNTIL SUCH TIME APPROPRIATE CORRECTIVE MEASURES CAN BE COMPLETED. THE NOAA WEATHER RADIO AT ROANOKE VIRGINIA...WXL60...WHICH BROADCASTS AT A FREQUENCY OF 162.475 MHZ...IS BACK ON THE AIR. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS NEAR TERM...DS/KK SHORT TERM...AMS/RAB LONG TERM...AMS AVIATION...DS/PC EQUIPMENT...DS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
341 PM CDT SAT MAY 2 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 341 PM CDT SAT MAY 2 2015 FORECAST FOCUS IS ON SMALL RAIN CHANCES TONIGHT...AND BETTER RISK FOR SHOWERS AND STRONG THUNDERSTORMS ON SUNDAY. WEAK SHORT WAVE TROUGH MOVING THROUGH IA THIS AFTERNOON WITH A FEW SHOWERS AND ISOLATED THUNDERSTORMS OCCURRING. MODELS HAVING SOME ISSUES WITH HOW TO HANDLE THIS FEATURE. DISTURBANCE IS MOVING DUE EAST AND SHOULD CONTINUE TO DO SO THIS EVENING. SOME MODELS INSIST ON NEW DEVELOPMENT OVERNIGHT IN THE DEFORMATION AREA ON THE BACK SIDE OF THE WAVE...LIKELY AS THE LOW LEVEL JET ENHANCES MOISTURE TRANSPORT INTO THE REGION. BUT NOT SOLD ON THAT HAPPENING. HAVE MAINTAINED A LOW CHANCE OVER OUR FAR SOUTHERN AREA BUT OTHERWISE LEAVING THE FORECAST DRY TONIGHT. OF LARGER CONCERN IS THE COLD FRONT MOVING THROUGH THE AREA SUNDAY AFTERNOON AND EVENING. A POTENT SHORT WAVE TROUGH WILL PASS INTO FAR NORTHERN MN LATE SUNDAY...HELPING SUPPORT THE FRONT AS IT DROPS SOUTHWARD. FRONTAL PASSAGE IN THE MOST OPPORTUNE TIME OF DAY...AND AMPLE MOISTURE LOOKS TO BE AVAILABLE AS SOUTHERLY WINDS CONTINUE TO ENHANCE TRANSPORT AHEAD OF THE BOUNDARY. MODEL CAPE FORECAST SUGGESTS AS MUCH AS 2500-3000 J/KG...BUT THIS LIKELY OVERDONE AS MODEL DEWPOINTS APPEAR TO BE INFLATED A BUT. BUT SUFFICE TO SAY THERE WILL BE ENOUGH INSTABILITY TO SUPPORT STRONG UPDRAFTS. BETTER SHEAR LOOKS TO LAG BEHIND THE FRONT...BUT ENOUGH PRESENT FOR STRONG STORMS...ESPECIALLY GIVEN THE COLD AIR MOVING IN BEHIND. HAIL AND STRONG WIND ARE A POSSIBILITY AND SPC INCLUDES OUR AREA IN THE DAY 2 SLIGHT RISK. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 341 PM CDT SAT MAY 2 2015 FRONT CONTINUES SOUTH THROUGH THE AREA EARLY MONDAY...BUT THEN STALLS OUT. BOUNDARY LOOKS TO LINGER AROUND THE GENERAL AREA ALL THE WAY INTO WEDNESDAY. WITH THIS BOUNDARY SERVING AS A FOCAL POINT...COULD SEE PERIODIC SHOWERS AND ISOLATED THUNDERSTORMS INTO MID WEEK. MEDIUM RANGE MODELS THEN IN GOOD AGREEMENT THAT A SIGNIFICANT SHORT WAVE TROUGH WILL EJECT NORTHEAST UP AND ACROSS OUR REGION OUT OF THE MEAN WEST COAST LONG WAVE TROUGH. THIS WILL PASS LATE WEDNESDAY AND THURSDAY. THIS WILL RESULT IN A COUPLE OF PERIODS OF SHOWERS AND THUNDERSTORMS. YET ANOTHER SIGNIFICANT SYSTEM LOOKS TO MOVE IN FOR NEXT WEEKEND...SO A PERIOD OF ACTIVE WEATHER LOOKS TO BE IN THE OFFING. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 102 PM CDT SAT MAY 2 2015 A SHORT WAVE TROUGH MOVING THROUGH THE MID MISSISSIPPI RIVER VALLEY IS PRODUCING A 7-12K BROKEN DECK OF CLOUDS SOUTH OF INTERSTATE 90. THE HRRR SUGGESTS THAT SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP IN THIS AREA AROUND 03.20Z. MEANWHILE THE RAP KEEPS THE AREA DRY. AT THIS TIME...LEANING MORE TOWARD THE RAP. THESE CLOUDS WILL MOVE EAST OF THE AREA BY 03.06Z. BOTH TAF SITES ARE ON THE NORTHERN EDGE...SO JUST MENTIONED A SCATTERED 7 TO 8K DECK. IN ADDITION TO THE CLOUDS...THE SOUTH WINDS WILL GUST INTO THE 20 TO 25 KNOT RANGE THROUGH 03.01Z. ON SUNDAY MORNING...A BROKEN 25K DECK OF CLOUDS WILL MOVE INTO THE AREA AHEAD OF AN APPROACHING COLD FRONT. WITH DIURNAL MIXING... THE WINDS WILL START TO GUST INTO THE 20 TO 25 KNOT RANGE AFTER 03.14Z. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...MW LONG TERM...MW AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
103 PM CDT SAT MAY 2 2015 .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 314 AM CDT SAT MAY 2 2015 WATER VAPOR SATELLITE IMAGERY THIS MORNING MAKES SOME SUGGESTION OF A WEAK SHORT WAVE TROUGH OVER EASTERN WYOMING. THIS IS THE FEATURE THE 02.00Z MODELS INDICATE WILL PASS ACROSS IOWA THIS AFTERNOON AND EVENING. THIS WAVE WILL ONLY BE ABLE TO PRODUCE SOME VERY WEAK PV ADVECTION IN THE 500-300 MB LAYER. HOWEVER...AS IT COMES ACROSS THE 02.00Z NAM SUGGEST THE LOW LEVEL RETURN FLOW WILL INCREASE DURING THE AFTERNOON AHEAD OF IT WITH SOME WEAK MOISTURE TRANSPORT INTO THE AREA AT 850 MB FOR LATE THIS AFTERNOON INTO THE EVENING. SOME ISENTROPIC UP GLIDE ON THE ORDER OF 1 TO 2 UBAR/S WILL DEVELOP AS WELL DURING THE LATE AFTERNOON AND THEN INCREASE TO 2 TO 4 UBAR/S OVERNIGHT ON THE 300K SURFACE. THE MOISTURE TRANSPORT ON THIS LAYER COULD ALSO INCREASE OVERNIGHT INTO THE AREA. THESE FEATURES COULD BE ENOUGH TO GENERATE A FEW SHOWERS AND STORMS SIMILAR TO WHAT THE NAM AND 02.00Z HI-RES NMM SHOW. WILL CONTINUE TO HAVE SOME RAIN CHANCES UP TO ABOUT 20 PERCENT FOR MOST OF THE AREA TONIGHT...BUT IF THE HI-RES MODELS ARE CORRECT...THE ACTIVITY COULD BE CONFINED TO THE IOWA/MINNESOTA BORDER AND SOUTH. THE FOCUS THEN TURNS TO THE SYSTEM COMING IN FOR SUNDAY AND SUNDAY NIGHT. THE SHORT WAVE TROUGH CURRENTLY OVER SOUTHERN BRITISH COLUMBIA WILL AMPLIFY AS IT MOVES EAST BUT FOR THE MOST PART REMAINS SOMEWHAT POSITIVELY TILTED AS IT MOVES ACROSS SOUTHERN CANADA AND THE EXTREME NORTHERN PORTIONS OF THE U.S. THE MODELS HAVE ALSO BEEN CONSISTENT IN TRYING TO SHOW SOME SECONDARY SHORT WAVE TROUGHS COMING ACROSS THE UPPER MIDWEST AHEAD OF THE MAIN SHORT WAVE TROUGH...WHETHER THESE BREAK OFF FROM THE MAIN TROUGH OR ARE GENERATED BY CONVECTION...IS DIFFERENT FROM MODEL TO MODEL. NONE OF THE MODELS REALLY GENERATE ANY PV ADVECTION OVER THE AREA WITH THE 02.00Z ECMWF THE FARTHEST SOUTH BRINGING SOME WEAK PV ADVECTION ACROSS NORTHERN WISCONSIN SUNDAY NIGHT. IF THIS IS TRUE...IS WILL LEAVE THE LOW LEVEL FORCING ALONG THE FRONT AS THE MAIN DRIVER FOR THE DEVELOPMENT OF THE CONVECTION. THE FRONTOGENESIS ALONG THE FRONT LOOKS TO MAINLY BE IN THE 1000-700 MB LAYER AND SHOULD BE WEAK TO MODERATE IN STRENGTH. THE ISENTROPIC UP GLIDE ON THE 305K SURFACE LOOKS LIKE IT SHOULD BE IN THE 3-5 UBAR/S RANGE. MOST OF THE MOISTURE TRANSPORT STILL LOOKS TO BE THROUGH THE AREA TERMINATING NORTH OF THE AREA WITH THE MAIN SHORT WAVE TROUGH. WITH THESE FORCING SIGNALS...HAVE SOME CONCERNS ABOUT HOW MUCH CONVECTION WILL ACTUALLY FORM ALONG THE FRONT. GRANTED...IT IS RIGHT AT THE END OF THE HI-RES MODEL RUNS...BUT THE ARW AND NMM BOTH ONLY SHOW A BROKEN AND NARROW LINE OF CONVECTION ALONG THE FRONT BY 00Z MONDAY. THESE MODELS ALSO SHOW THIS ONLY GETTING INTO THE FAR NORTHWESTERN SECTIONS OF THE FORECAST AREA LATE SUNDAY AFTERNOON. THE STORMS THAT DO DEVELOP STILL LOOK TO HAVE SOME POTENTIAL TO PRODUCE SEVERE WEATHER WITH DAMAGING WINDS AND LARGE HAIL THE MAIN THREATS. AN AXIS OF 1500 J/KG OF ML CAPE SHOULD BE IN PLACE AHEAD OF THE FRONT FOR SUNDAY AFTERNOON INTO THE EARLY EVENING. THE BEST SHEAR WILL BE CONFINED TO THE 0-3 KM LAYER BUT MAY BE ONLY ABOUT 25 KNOTS AHEAD OF THE FRONT WITH THE NAM AND GFS SHOWING THE BEST SHEAR REMAINING BEHIND THE FRONT. THE FRONT AND CONVECTION SHOULD MOVE THROUGH PRETTY QUICKLY SUNDAY NIGHT WITH THE ACTIVITY CONFINED TO THE SOUTHEAST HALF OR SO OF THE AREA AFTER 06Z MONDAY. THE FRONT THEN LOOKS TO BECOME STATIONARY SOUTH OF THE AREA FOR MONDAY. THERE WILL BE ACTIVITY ALONG AND NORTH OF THE FRONT AND THE CONCERN IS JUST HOW FAR NORTH THIS WILL EXTENT. THE NAM AND ECMWF WOULD SUGGEST IT WOULD STAY SOUTH OF THE AREA WHILE THE GFS BRINGS IT INTO THE SOUTHERN SECTIONS OF THE AREA. IF THE FRONT DOES MAKE IT INTO NORTHERN MISSOURI BEFORE STALLING OUT...WHICH IS THE MODEL CONSENSUS...FEEL THE NAM AND ECMWF HAVE A BETTER CHANCE OF BEING CORRECT AND WILL ONLY SHOW A SMALL CHANCE ACROSS THE SOUTH TO HONOR THE GFS. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 314 AM CDT SAT MAY 2 2015 ONCE THE SHORT WAVE TROUGH FROM SUNDAY NIGHT MOVES PAST THE AREA...THE FLOW IS STILL EXPECTED TO BECOME SOUTHWEST WITH A LARGE UPPER LEVEL LOW OFF THE PACIFIC NORTHWEST COAST AND ANOTHER LOW OVER THE SOUTHWEST. AS THE LOW OFF THE NORTHWEST COAST MOVES INLAND AND THE UPPER LEVEL RIDGE AMPLIFIES OVER THE SOUTHEAST CONUS...IT WILL FORCE THE SOUTHWEST SYSTEM TO MOVE NORTHEAST TOWARD THE REGION THROUGH THE PERIOD. IT DOES NOT LOOK LIKE THIS WILL COME THROUGH AS ONE PIECE OF ENERGY BUT ACTUALLY GET STRUNG OUT AND ACT AS SEVERAL SHORT WAVE TROUGHS. THE FRONT THAT STALLS SOUTH OF THE AREA WILL GET DRAWN BACK NORTH TUESDAY AND TUESDAY NIGHT AND SHOULD BE NORTH OF THE AREA BY WEDNESDAY NIGHT. A COLD FRONT WILL THEN START TO APPROACH FROM THE WEST THURSDAY AND MOVE INTO THE AREA FRIDAY. WITH THIS PATTERN...WILL HAVE TO CARRY RAIN CHANCES FOR EACH PERIOD BUT DOUBTFUL THERE WILL ACTUALLY BE THAT MUCH RAIN AROUND. COULD SEE SOME POTENTIAL FOR A DRY PERIOD OR TWO ONCE THE FRONT MOVES NORTH OF THE AREA...BUT CONFIDENCE IS NOT HIGH ENOUGH TO TRY AND INCORPORATE THAT INTO THE FORECAST AT THIS TIME. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 102 PM CDT SAT MAY 2 2015 A SHORT WAVE TROUGH MOVING THROUGH THE MID MISSISSIPPI RIVER VALLEY IS PRODUCING A 7-12K BROKEN DECK OF CLOUDS SOUTH OF INTERSTATE 90. THE HRRR SUGGESTS THAT SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP IN THIS AREA AROUND 03.20Z. MEANWHILE THE RAP KEEPS THE AREA DRY. AT THIS TIME...LEANING MORE TOWARD THE RAP. THESE CLOUDS WILL MOVE EAST OF THE AREA BY 03.06Z. BOTH TAF SITES ARE ON THE NORTHERN EDGE...SO JUST MENTIONED A SCATTERED 7 TO 8K DECK. IN ADDITION TO THE CLOUDS...THE SOUTH WINDS WILL GUST INTO THE 20 TO 25 KNOT RANGE THROUGH 03.01Z. ON SUNDAY MORNING...A BROKEN 25K DECK OF CLOUDS WILL MOVE INTO THE AREA AHEAD OF AN APPROACHING COLD FRONT. WITH DIURNAL MIXING... THE WINDS WILL START TO GUST INTO THE 20 TO 25 KNOT RANGE AFTER 03.14Z. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1106 PM MDT FRI MAY 1 2015 .UPDATE... ISSUED AT 959 PM MDT FRI MAY 1 2015 WE HAVE ADDED AREAS OF DENSE FOG THROUGH AROUND 1 AM FOR THE INTERSTATE 80 SUMMIT BETWEEN LARAMIE AND CHEYENNE AS WELL AS OVER THE WESTERN FOOTHILLS OF LARAMIE COUNTY BASED ON WEBCAMS. WE BELIEVE THE FOG WILL QUICKLY DISSIPATE BETWEEN MIDNIGHT AND 3 AM AS THE BOUNDARY LAYER WINDS BECOME WEST. UPDATE ISSUED AT 932 PM MDT FRI MAY 1 2015 GRIDDED FORECASTS UPDATED TO REMOVE SHOWERS AND THUNDERSTORMS FOR THE REST OF THE NIGHT AND TO ADJUST TEMPERATURES...DEWPOINTS...WINDS AND CLOUD COVER FOR THE REST OF THE NIGHT. UPDATE ISSUED AT 602 PM MDT FRI MAY 1 2015 OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON TRENDS. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 354 PM MDT FRI MAY 1 2015 SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80 CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON... WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY. QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON... BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700 MILLIBAR TEMPS AROUND 8-10 DEG C. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 354 PM MDT FRI MAY 1 2015 THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS. SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE. ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE 60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1102 PM MDT FRI MAY 1 2015 PATCHY FOG WITH IFR CONDITIONS NEAR THE SOUTHERN LARAMIE RANGE WILL PERSIST THE NEXT FEW HOURS BUT SHOULD DISSIPATE AS WEST WINDS ERODE THE FOG. FOG WILL BE POSSIBLE AT THE KCYS TAF SITE BUT OTHER TAF SITES WILL LIKELY NOT BE AFFECTED TONIGHT. OTHERWISE FOR TONIGHT THROUGH TOMORROW MORNING VFR FOR MOST OF THE FORECAST AREA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN DEVELOP SATURDAY AFTERNOON. GUSTY WINDS AND SMALL HAIL WILL BE POSSIBLE WITH SOME STORMS. && .FIRE WEATHER... ISSUED AT 354 PM MDT FRI MAY 1 2015 FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...RUBIN SHORT TERM...CLH LONG TERM...CAH AVIATION...SML FIRE WEATHER...CLH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1123 PM MDT SUN MAY 3 2015 .UPDATE... ISSUED AT 848 PM MDT SUN MAY 3 2015 BASED OFF TRENDS OF HRRR...RUC AND 00Z NAM...HAVE BUMPED UP POPS ALONG I-25 CORRIDOR.S MTNS REGION FOR LATER TONIGHT INTO EARLY TOMORROW MORNING. GUIDANCE SHOWING PRETTY GOOD UPSLOPE DEVELOPING LATER TONIGHT. THIS ALONG WITH THE 700 MB CIRC DEVELOPING OVER THE SE PLAINS TONIGHT AND THE GOOD LOWER LEVEL EASTERLY FLOW...SEE NO REASON TO GO AGAINST THE GUIDANCE. IF HRRR CONTINUES WITH THE PRECIP...WILL HAVE TO BUMP UP POPS IN A LATER FCST UPDATE. /HODANISH && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 234 PM MDT SUN MAY 3 2015 SHOWERS AND STORMS THAT HAVE DEVELOPED THIS AFTERNOON HAVE GENERALLY BE FAIRLY SLOW MOVING AND SHORT LIVED. ISOLATED TO SCATTERED SHOWERS AND TSTMS OVR THE AREA WL CONTINUE INTO THE EVENING HOURS...AND DECREASING TOWARD MIDNIGHT. A COLD FRONT WL MOVE SOUTH INTO THE SOUTHEAST PLAINS THIS EVENING...WITH THE NAM SHOWING IT REACHING THE SRN CO BORDER EARLY MON MORNING. BEHIND THE FRONT...SFC DEW POINTS INCREASE INTO THE 40S...AND LOW STRATUS IS FORECAST TO DEVELOP OVR NORTHERN EL PASO COUNTY BY MIDNIGHT AND THEN SPREADING SOUTHWARD OVERNIGHT. THE HRRR...NSSL WRF AND NAM CONTINUE TO SHOW PCPN BEHIND THE FRONT OVR EL PASO AND TELLER COUNTIES DURING THE LATE NIGHT HOURS...WITH MUCH OF THE REST OF THE FORECAST AREA BEING DRY. THE HRRR SPREADS PCPN SOUTHWARD INTO PUEBLO AND FREMONT COUNTIES AS WELL. ON MONDAY AN UPR LOW BECOME CENTERED OVR THE CA AND AZ BORDER WITH SOUTHERLY FLOW ALOFT OVR THE FORECAST AREA AHEAD OF THIS SYSTEM...DRAWING MSTR NORTHWARD. WITH MOIST LOW TO MID LEVEL SOUTHEASTERLY WINDS...KEEPING AFTERNOON SFC DEW POINTS ACRS THE SERN PLAINS IN THE MID40S TO LOWER 50S. MOST OF THE LOW STRATUS IS EXPECTED TO DISSIPATE BEFORE AFTERNOON. THE NAM SHOWS SHOWERS/TSTMS DEVELOPING IN THE MID MORNING HOURS OVR THE MTNS...ESPECIALLY ALONG THE CONTDVD...WHERE A SHORTWAVE TROF IS EXPECTED TO MOVE NORTHWARD THRU THE AREA. PCPN WL INCREASE ACRS THE MTNS BY MIDDAY AND WL SPREAD TO THE ADJACENT LOWER ELEVATIONS...AND THEN THROUGH THE AFTERNOON WL BECOME WIDESPREAD ACRS MOST OF THE FORECAST AREA. THERE WL BE THE POTENTIAL FOR LOCALIZED HEAVY RAIN. ALSO...PORTIONS OF THE SERN PLAINS COULD SEE ONE OR TWO MARGINALLY SEVERE STORMS IN THE AFTERNOON. HIGH TEMPS ON MON WILL BE COOLER THAN TODAY AND SHOULD GENERALLY BE JUST A LITTLE BELOW NORMAL. HIGH TEMPS IN THE SAN LUIS VALLEY SHOULD BE CLOSE TO NORMAL. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 234 PM MDT SUN MAY 3 2015 ...STORMY WEATHER THROUGH TUESDAY... MONDAY NIGHT...WILL SEE SEVERAL ONGOING ROUNDS OF PRECIP AND STORMS OVER THE AREA. THE STRONGEST OF THESE WILL LIKELY BE OVER THE ERN PLAINS...GENERALLY E OF KLHX...AND ANOTHER AREA OVER THE PALMER DVD. GIVEN THE ABUNDANT LLVL MOISTURE AND INCREASED SHEAR DUE TO BACKED LLVL FLOW...CANNOT RULE OUT A STRONG TO SVR STORM OR TWO ESPECIALLY IN THESE FAVORED AREAS. COULD SEE A BRIEF LULL IN THE PRECIP MON EVE BEFORE PRECIP COVERAGE INCREASES LATER MON NIGHT...IN BANDS OF CONVECTION ROTATING UP FROM THE SOUTH. WILL MAINTAIN ISOLD OR SLIGHT CHANCE OF TS OVERNIGHT ALONG WITH MORE WIDESPREAD LIKELY POPS ACROSS THE MTS AND PLAINS. ON TUE...THE UPPER LOW WILL MOVE INTO THE FOUR CORNERS REGION...THEN TRACK TO THE NE DURING THE DAY. TEMPS WILL BE COOLER...IN THE 60S FOR THE PLAINS...DUE TO WIDESPREAD CLOUDS AND PRECIP. IT LOOKS LIKE MUCH OF THE BEST PRECIP COVERAGE WILL BE TUE MORNING...ALTHOUGH EVEN IF THERE ARE ANY BREAKS IN THE SHOWERS AND STORMS...THEY SHOULD PICK UP AGAIN BY TUE AFTERNOON. SNOW LEVELS MON-TUE WILL BE PRETTY HIGH...BUT GIVEN THE AMOUNT OF QPF...COULD SEE SOME LOCAL SIGNIFICANT ACCUMS IN THE MTS OF SIX INCHES OR MORE...ESPECIALLY ABOVE 12000 FEET. SO...RECREATIONISTS SHOULD BE AWARE OF WINTER CONDITIONS FOR THE HIGH PEAKS. GIVEN ALL THE PRECIP...THE BL SHOULD BE PRETTY STABILIZED BY TUE SO SURFACE BASED CONVECTION LOOKS UNLIKELY. BUT...A STRONG STORM OR TWO CANNOT BE RULED OUT OVER THE AREA AS THE UPPER LOW MOVES THROUGH NRN CO. BY WED...SHOULD SEE THINGS WINDING DOWN AS THE FIRST UPPER LOW MOVES OFF INTO THE DAKOTAS AND NE. WILL STILL SEE SOME WRAP AROUND PRECIP OVER THE DVD AND NRN PORTIONS OF THE CWA. TEMPS SHOULD REBOUND NICELY BACK INTO THE 70S OVER THE PLAINS. THE NEXT SYSTEM WILL DROP SWD FROM THE PACNW ON WED...THEN CUTOFF OVER CA THU-SAT...AND SLOWLY MOVE TO THE NE OVER THE WEEKEND. GLOBAL MODELS ARE STILL IN GOOD AGREEMENT THAT THIS SYSTEM WILL TRACK TO OUR NORTH NEXT WEEKEND...ALTHOUGH LATEST RUNS HINT THAT THE TRACK MAY BE A BIT FARTHER SOUTH. STILL LOOKS LIKE MOST OF SE CO WILL BE STUCK IN THE DRY SW FLOW TO THE SOUTH OF THE LOW...BUT GIVEN THE UNCERTAINTIES WILL MAINTAIN POPS OVER THE AREA...ESPECIALLY FOR THE MTS. TEMPS WILL BE CONSIDERABLY LOWER WITH THIS SYSTEM...AS H7 TEMPS ARE MINUS THREE OR LOWER...SO SOME MTN SNOWS SEEM LIKE A GOOD BET. ROSE && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1118 PM MDT SUN MAY 3 2015 IT WILL BE MUCH WETTER AT THE TAF SITES DURING THE NEXT 24H. A MOIST PACIFIC STORM COMING IN FROM S CALIF WILL AFFECT THE REGION THE NEXT COUPLE OF DAYS. FOR KCOS AND KPUB...SHOWERS WILL BE POSSIBLE TONIGHT INTO EARLY TOMORROW. WE WILL LIKELY SEE SOME MVFR CONDITIONS LATER TONIGHT. WE WILL SEE A BREAK LATER TOMORROW MORNING...THEN ANOTHER DISTURBANCE WILL BRING ADDITIONAL ROUNDS OF SHOWERS AND STORMS TO THE TWO TAF SITE. MVFR TO IFR CONDITIONS MAY OCCUR TOMORROW EVENING. THE RAIN COULD BE HEAVY AT TIMES TOMORROW AFTERNOON/EVENING. AT KALS..OCCASIONAL SHOWERS WITH ISOLD THUNDER WILL BE POSSIBLE DURING THE NEXT 24H. MVFR CONDITIONS WILL BE POSSIBLE AT TIMES IN THE HEAVIER SHOWERS. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HODANISH SHORT TERM...28 LONG TERM...ROSE AVIATION...HODANISH
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1147 PM CDT SUN MAY 3 2015 .UPDATE... ISSUED AT 852 PM CDT SUN MAY 3 2015 CONVECTION CONTINUES TO FIRE THIS EVENING ALONG A FRONTAL BOUNDARY EXTENDING FROM NORTHWEST ONTARIO INTO THE CENTRAL PLAINS. THE NORTHERN PORTION THE LINE, WELL NORTH OF THE FORECAST AREA, IS MAKING THE MOST RAPID EASTWARD PROGRESS. THIS IS NOT SURPRISING GIVEN THE STRONGER WIND FIELDS IN THAT AREA, AND THE FORECAST WEST-EAST ORIENTATION OF THE FRONTAL BOUNDARY THAT IS ANTICIPATED BY LATER TOMORROW. A FEW LIGHT SHOWERS ARE PUSHING INTO THE WESTERN PORTIONS OF THE FORECAST AREA WELL IN THE PRE-FRONTAL WARM SECTOR, AND THIS SHOULD CONTINUE TO WANE WITH THE LOSS OF DIURNAL HEATING. THE CONVECTION ALONG THE FRONT WILL CONTINUE TO PUSH TOWARD AT LEAST THE NORTHERN PORTION OF THE AREA BY LATE TONIGHT AS THE UPPER-LEVEL WAVE HELPING TO DRIVE THEM MOVES THROUGH. HOWEVER, THEY SHOULD ARRIVE IN A SUBSTANTIALLY WEAKENED STATE CONSIDERING THE LOSS OF DIURNAL INSTABILITY AND FORECAST WEAKENING OF THE LOW-LEVEL JET BY THE TIME THEY ARRIVE. GOING FORECAST IS IN GOOD SHAPE OVERALL. MOST SIGNIFICANT ADJUSTMENTS NEEDED ARE TOWARD PRECIPITATION TRENDS, MOST NOTABLY TO REMOVE THUNDER MENTION FROM THIS EVENING AND DELAY ARRIVAL OF THE UPSTREAM CONVECTION A BIT. && .SHORT TERM...(TONIGHT) ISSUED AT 250 PM CDT SUN MAY 3 2015 A WEAKENING SHORT WAVE OVER EASTERN IA AND NW IL BY MS RIVER WILL LIFT INTO SE WI BY SUNSET AND KEEP BEST CHANCES OF SHOWERS AND THUNDERSTORMS NORTH OF I-80 THROUGH SUNSET WITH JUST ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS OVER THE IL RIVER VALLEY. CHANCES OF SHOWERS AND THUNDERSTORMS WILL INCREASE DURING THE NIGHT ESPECIALLY OVERNIGHT OVER THE IL RIVER VALLEY WITH SLIGHT CHANCES EXTENDING AS FAR SE AT CHARLESTON/MATTOON BY SUNRISE MONDAY AS YET ANOTHER SHORT WAVE OVER EASTERN NEBRASKA TRACKS EAST TOWARD THE IA/IL BORDER BY 12Z/7 AM MONDAY. SPC KEEPS RISK OF SEVERE STORMS NW OF IL OVER NORTHERN IA, SE MN AND INTO CENTRAL WI THROUGH DAYBREAK MONDAY WHERE BETTER FORCING WILL BE AS COLD FRONT PUSHES SE INTO CENTRAL PARTS OF WI/IA BY SUNRISE MONDAY. STAYED CLOSE TO MET/MAV GUIDANCE LOWS TONIGHT IN THE UPPER 50S AND LOWER 60S WITH COOLEST READINGS IN EASTERN/SE IL. BREEZY SSW WINDS 15-25 MPH THIS AFTERNOON WILL DIMINISH SOUTH 7-14 MPH AFTER SUNSET. .LONG TERM...(MONDAY THROUGH SUNDAY) ISSUED AT 250 PM CDT SUN MAY 3 2015 MAIN FORECAST CHALLENGE WILL BE POSITION OF FRONTAL BOUNDARY AND HIGHER RAIN CHANCES LATER TONIGHT THRU MONDAY NIGHT. REMNANTS OF TODAY`S MCV SHOULD PUSH OFF TO OUR NORTHEAST PUSHING THE SHOWERS EVEN FURTHER AWAY FROM THE FORECAST AREA THIS EVENING. WEAK UPPER LEVEL DISTURBANCE OVER THE MISSOURI VALLEY HAS A FEW SHOWERS ASSOCIATED WITH IT BUT THE LAST FEW RUNS OF THE RAP AND HRRR HAVE BACKED OFF SOME ON ANY ORGANIZED SHOWER AND THUNDERSTORM THREAT WITH THAT FEATURE. IT STILL APPEARS OUR MAIN THREAT WILL COME LATER TONIGHT AND THRU THE MORNING HOURS OF MONDAY WITH REDEVELOPMENT TAKING PLACE LATER TOMORROW AFTERNOON INTO THE EVENING RIGHT ALONG THE STALLED FRONTAL BOUNDARY. HAVE TRENDED MORE TOWARDS THE HIGH RESOLUTION MODEL SOLUTIONS FROM THE NSSL-ARW AND 4KM NAM-WRF WITH RESPECT TO FRONTAL POSITION ON MONDAY AND ASSOCIATED PRECIP CHANCES ALONG IT. THE HIGHER POPS WILL REMAIN ACROSS THE NORTHERN HALF OF THE FORECAST AREA BEFORE THE BOUNDARY SHIFTS BACK NORTH LATE TUESDAY INTO WEDNESDAY AS UPPER LEVEL RIDGING BUILDS ACROSS THE REGION. SEVERE THREAT WILL BE TIED TO THE POSITION OF THE BOUNDARY MONDAY AFTERNOON AND EVENING WITH THE NAM-WRF INDICATING A 40-45 KT LOW LEVEL JET SETTING UP TONIGHT FROM NORTHERN MISSOURI NORTHEAST INTO NORTHERN IL WITH THE STRONGER 850 MB THETA-E ADVECTION AND MOISTURE TRANSPORT LOCATED FROM NORTHEAST MISSOURI INTO NORTHERN IL. STORMS SHOULD DEVELOP WELL OUT TO OUR WEST AND NORTHWEST LATER THIS EVENING AND THEN TRANSLATE EAST AND SOUTHEAST INTO OUR NORTHERN AREAS BY LATE EVENING OR DURING THE EARLY MORNING HOURS OF MONDAY. IF A DECENT COLD POOL DEVELOPS LATER TONIGHT...THOSE STORMS MAY TRACK FURTHER SOUTH AND AFFECT THE POSITION OF THE SYNOPTIC SCALE BOUNDARY IN OUR AREA ON MONDAY/MONDAY EVENING. WITH THE WEST TO EAST BOUNDARY LOCATED ACROSS A PORTION OF THE FORECAST AREA MONDAY AFTERNOON AND EVENING...LOOK FOR STORMS TO FIRE AGAIN ALONG THE INSTABILITY AXIS WHICH SHOULD BE ALIGNED FROM NORTHERN MISSOURI INTO WEST CENTRAL IL BY MID AFTERNOON. MIXED LAYER CAPES OF 1500-2000 J/KG AND EFFECTIVE SHEAR VALUES OF 25 KTS SHOULD PROMOTE STORM ORGANIZATION WITH ISOLATED STRONG WIND GUSTS AND HAIL POSSIBLE WITH 700-500 MB LAPSE RATES OF 6.5-7 DEG/C DEPICTED ON SOUNDINGS TOMORROW AFTERNOON ACROSS THE NORTH. SCATTERED STORMS SHOULD CONTINUE MONDAY NIGHT AND THEN BEGIN TO EDGE NORTHWARD BY TUESDAY AS THE UPPER LEVEL RIDGING BEGINS TO AMPLIFY ACROSS THE MIDWEST. ONCE THE 500 MB RIDGE BUILDS OVER THE AREA ON TUESDAY...SHOWER AND THUNDERSTORM CHANCES WILL SHIFT NORTH CLOSER TO THE RETREATING SURFACE BOUNDARY. OUR NEXT THREAT WILL BE ASSOCIATED WITH A LEAD SHORTWAVE TROF THAT IS FORECAST TO EJECT NORTHEAST INTO THE SOUTHERN AND CENTRAL PLAINS ON THURSDAY WITH THE HIGHEST POPS...AT LEAST INITIALLY...ACROSS THE WEST AS MODELS SUGGEST MOST OF THE STRONGER LIFT AND INSTABILITY WILL SHIFT MORE NORTH THAN EAST. HOWEVER...OUR AREA WILL BE UNDER A SOUTHWEST FLOW ALOFT LATE IN THE WEEK AND INTO NEXT WEEKEND WITH A DEEPER UPPER LEVEL LOW FORECAST BY MEDIUM RANGE MODELS TO PUSH OUT OF THE PLAINS AND INTO THE MIDWEST BY LATE IN THE WEEKEND. UNFORTUNATELY...THIS TYPE OF A PATTERN THIS TIME OF YEAR BRINGS DAILY CHANCES FOR SHOWERS AND STORMS BUT AT LEAST THE TEMPERATURES WILL REMAIN ABOVE NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1142 PM CDT SUN MAY 3 2015 WEAKENING LINE OF SHOWERS/STORMS APPROACHING CENTRAL ILLINOIS FROM THE NORTHWEST LATE THIS EVENING. FURTHER WEAKENING IS ANTICIPATED AND THEY MAY NOT REACH THE BULK OF THE LOCAL TERMINALS. KPIA AND KBMI STAND THE BEST CHANCE OF SEEING STORMS. ADDITIONAL CONVECTION OVER THE CENTRAL PLAINS IS MOVING MORE OF AN EASTERLY DIRECTION AND THESE MAY IMPACT A PORTION OF THE REGION AS WELL VERY LATE TONIGHT OR MONDAY MORNING. HOWEVER, IN BOTH CASES, COVERAGE BY THE TIME THEY GET HERE IS NOT EXPECTED TO BE HIGH, SO HAVE GONE WITH A VCSH/VCTS MENTION FOR NOW. ASIDE FROM ANY OF THIS CONVECTION, EXPECT VFR CONDITIONS TO PREVAIL FOR MOST OF THE 06Z TAF VALID TIME. EXPECT MOST OF THE ADDITIONAL DEVELOPMENT ON MONDAY TO STAY MOSTLY TO THE NORTH OF THE AREA, ALONG A STALLED FRONTAL BOUNDARY, ALTHOUGH KPIA AND KBMI STILL STAND THE BEST CHANCE OF BEING IMPACTED. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BAK SHORT TERM...07 LONG TERM...SMITH AVIATION...BAK
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1138 PM MDT SUN MAY 3 2015 .UPDATE... ISSUED AT 534 PM MDT SUN MAY 3 2015 ISSUED MINOR FORECAST UPDATE TO ACCOUNT FOR LATEST TRENDS WITH POPS...WINDS AND SKY. SLOW MOVING THUNDERSTORMS HAVE DEVELOPED SOUTH OF INTERSTATE 70. DUE TO SLOW MOVEMENT...RAINS HAVE BEEN HEAVY AT TIMES. WILL NEED TO REFINE QPF AND QPE SHORTLY. STORMS HAVE BEEN SUB-SEVERE SO FAR BUT A FEW HAVE APPROACHED SEVERE LIMITS. MAIN THREATS WITH THESE STORMS IS DAMAGING WINDS AND LARGE HAIL IF THEY WERE TO BECOME SEVERE. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 224 PM MDT SUN MAY 3 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW WESTERLY FLOW IN PLACE ACROSS THE PLAINS WITH A SHORTWAVE TROUGH UPSTREAM OVER THE CENTRAL ROCKIES. AT THE SURFACE A TROUGH IS CURRENTLY IN PLACE OVER THE CWA...WITH A COLD FRONT NEAR IMPERIAL NEBRASKA EXTENDING INTO NORTHEAST COLORADO. REGIONAL RADAR SHOWS SCATTERED THUNDERSTORM ACTIVITY ALREADY MOVING OFF THE HIGHER TERRAIN IN COLORADO AND MOVING OFF THE PALMER DIVIDE TOWARDS THE WESTERN PART OF OUR CWA. THIS AFTERNOON-TONIGHT...WINDOW FOR SEVERE WEATHER APPEARS TO BE MAINLY AHEAD OF COLD FRONT WHERE MODELS HAD BEEN ADVERTISING MODERATE INSTABILITY DEVELOPING BY 00Z (MAINLY EAST OF SURFACE TROUGH). SO FAR RAP ANALYSIS SHOWS ML CAPE GENERALLY AROUND 500 J/KG LIKELY DUE TO MUCH LOWER TD VALUES AHEAD OF COLD FRONT THAN PREVIOUSLY ANTICIPATED. HRRR/RAP HAVE BEEN SHOWING ISOLATED DEVELOPMENT ALONG SURFACE TROUGH AXIS WHERE CAP HAS BEEN WEAKENED. THERE IS A WINDOW FOR INCREASING SHEER AS COLD FRONT MOVES SOUTH AND DEPENDING ON STRENGTH OF UPDRAFTS WE COULD SEE SOME ORGANIZED CELLS...OTHERWISE IT APPEARS TO BE AN ENVIRONMENT FAVORING PULSE TYPE THUNDERSTORMS THROUGH MOST OF THE NIGHT. DCAPE VALUES IN EXCESS OF 1000 J/KG DO RAISE CONCERNS FOR MICROBURST POTENTIAL AHEAD OF COLD FRONT SO EVEN WEAKER UPDRAFTS COULD PRODUCE NEAR SEVERE OR SEVERE WINDS AS THEY COLLAPSE. SHOWER AND THUNDERSTORM COVERAGE WILL INCREASE LATE THIS EVENING ALONG/NORTH OF COLD FRONT WITH INCREASING MOISTURE RETURN AND ELEVATED CAPE IN PLACE. BY LATE TONIGHT INSTABILITY BEGINS TO WANE...WHILE LARGE SCALE FORCING STARTS TO SHIFT NORTH AND EAST OF THE REGION. THIS IS WHERE MODELS DIVERGE WITH NAM CONTINUING TO INDICATE AND LULL OR DRY PERIOD WHILE ECMWF/GFS INDICATE POSSIBLE OVERRUNNING OR STRATUS/FOG/DRIZZLE DEVELOPMENT ALONG/NORTH OF THE FRONT. TOUGH CALL AND WHILE I HEDGED TOWARD THE DRY NAM AT 12Z...I COULD SEE IN THIS TYPE OF PATTERN A LIGHT PRECIP/DRIZZLE EVEN EVOLVING BY MONDAY MORNING. MONDAY...UPPER LOW OVER THE SOUTHWEST US BEGINS TO DEEPEN AND MOVE EAST WITH BETTER LARGE SCALE FORCING SPREADING OVER THE CWA BY LATE AFTERNOON. DEPENDING ON WHAT HAPPENS TO POSSIBLE STRATUS DURING THE DAY WE MAY OR MAY NOT HAVE A WINDOW FOR SEVERE THUNDERSTORMS IN THE EASTERN PART OF OUR CWA WHERE MODELS SHOW WAA AND INCREASING TDS/INSTABILITY. FURTHER NORTH AND WEST STRATUS IS MORE LIKELY TO LINGER...HOLDING TEMPS DOWN IN AND ANY INSTABILITY WOULD BE ELEVATED AND WEAKER. DEPENDING ON CHOICE IN MODEL SHOWERS/THUNDERSTORMS COULD BE POSSIBLE THROUGH THE DAY...HOWEVER BETTER CHANCES SHOULD BE TIED TO STRONGER LARGE SCALE FORCING LATER DURING THE DAY MONDAY. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 224 PM MDT SUN MAY 3 2015 SOUTHWEST FLOW WILL PRECEDE AN UPPER TROUGH THAT WILL AFFECT THE CENTRAL PLAINS TUESDAY THROUGH WEDNESDAY. SURFACE HIGH PRESSURE WILL SHIFT EAST ACROSS THE CENTRAL PLAINS MONDAY NIGHT AS LOW PRESSURE MOVES INTO COLORADO TUESDAY. LOW PRESSURE WILL REMAIN OVER COLORADO AND WESTERN KANSAS THROUGH WEDNESDAY. POPS WILL INCREASE FROM MONDAY EVENING TO OVERNIGHT AS BETTER DYNAMICS AND MOISTURE MOVE NORTH INTO THE FA. PLAN TO GO WITH CHANCE POPS ACROSS THE WESTERN PORTION OF THE FA DURING THE EVENING WITH LIKELY POPS OVER THE SOUTHEAST ZONES CLOSER TO THE SURFACE BOUNDARY. LIKELY POPS WILL SPREAD NORTH ACROSS THE FA OVERNIGHT AS VERY FAVORABLE MOISTURE AND LIFT MOVE INTO THE FA. LIKELY AND DEFINITE POPS WILL BE USED ACROSS THE ENTIRE FA TUESDAY AND TUESDAY EVENING AS GOOD DYNAMICS AND MOISTURE CONTINUE TO STREAM NORTHWARD ACROSS THE FA. PRECIPITABLE WATER VALUES ARE AROUND AN INCH SO WILL INCLUDE MODERATE RAIN IN THE GRIDS TUESDAY. POPS WILL START DECREASING TO CHANCE POPS AFTER 06Z WEDNESDAY AS THE UPPER TROUGH STARTS TO LIFT OUT OF THE AREA. SOME LIKELY POPS WILL STILL EXIST ACROSS THE NORTHERN FA WEDNESDAY AFTERNOON AS INSTABILITY INCREASES. MIN TEMPERATURES MONDAY NIGHT SHOULD COOL TO THE MID 40S IN EASTERN COLORADO AND THE MID 50S IN THE EASTERN FA. MIN TEMPERATURES TUESDAY NIGHT WILL RANGE FROM THE LOWER TO MID 50S. MAX TEMPERATURES TUESDAY SHOULD RANGE FROM 65 TO 70 AND 70 TO 75 WEDNESDAY. IN THE EXTENDED...(WEDNESDAY NIGHT THROUGH SUNDAY)...THE UPPER TROUGH LIFTS NORTHEAST WEDNESDAY NIGHT WITH SOUTHWEST FLOW FOLLOWING THROUGH SATURDAY. THE NEXT UPPER TROUGH MOVES INTO THE PLAINS SATURDAY NIGHT AND SUNDAY. SHORTWAVES MOVING THROUGH THE FLOW AND INCREASING DYNAMICS WITH THE NEXT TROUGH SATURDAY NIGHT AND SUNDAY WILL KEEP AT LEAST A CHANCE OF THUNDERSTORMS ACROSS THE FA EACH DAY. MIN TEMPERATURES THROUGH SATURDAY NIGHT SHOULD RANGE FROM 45 TO 55. MAX TEMPERATURES WILL GENERALLY RANGE FROM THE MID 60S TO THE MID 70S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1138 PM MDT SUN MAY 3 2015 OVERALL THINKING FOR STRATUS/FOG REMAINS LARGELY UNCHANGED. HAVE GROWN LESS CONFIDENT MVFR FOG WILL BE OBSERVED AT KGLD SO HAVE REMOVED FOG MENTION. FORECAST GUIDANCE BECAME MORE OPTIMISTIC TOWARDS CEILINGS SO FEEL THAT IFR CEILINGS ARE UNLIKELY NOW. MVFR CEILINGS BETWEEN 1000-2000 FEET ARE THE MOST LIKELY SCENARIO. SHORT TERM THREAT OF THUNDERSTORMS AT KMCK HAS BECOME THE MORE SIGNIFICANT ISSUE. ELEVATED STORMS CONTINUE MOVING TO THE NORTH. STORMS COULD CONTAIN GUSTY WINDS...SMALL HAIL AND HEAVY RAINS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...RRH SHORT TERM...DR LONG TERM...FS AVIATION...RRH
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1154 PM CDT Sun May 3 2015 ...Update to aviation forecast discussion... .SHORT TERM...(This Evening through Monday) Issued at 328 PM CDT SUN MAY 3 2015 Zonal but weak flow aloft continues over the Central Plains between northern and southern branches with a few weak waves moving through. Appears moderate mid-level isentropic lift combined with one of these waves to spark overnight convection, with another wave keeping isolated showers going in eastern Kansas into the early afternoon. High- based nature of this activity keeping much precip from what there is in check however. Water vapor imagery suggesting a stronger wave rotating northeast out of eastern New Mexico with convection firing ahead of it into southeastern Colorado. Cold front was from northwestern Kansas into northeastern Nebraska early this afternoon with a few cumulus along it in central Nebraska. Dewpoints have dropped to around 40F in southwest Kansas with thermal ridge ahead of front pushing temp at CNK to near record levels. Precipitation chances remain the main challenge through Monday afternoon. Recent HRRR and RAP runs continue to attempt to produce convection along the front, but have been too fast to do so. With low levels rather dry to the west, the main player with convection to the west and south could be via the New Mexico wave, or other convective-induced waves from eastern Colorado. Isentropic upglide looks less impressive than this morning but some is again present and could be enough to continue or even produce convection into east central Kansas late this evening and into much of Monday. Other prime scenario for convection seems to be with eventual convection generated in eastern Nebraska sinking south into northeast Kansas on decent 850mb moisture convergence as a moderate low level jet veers with time. This could linger well into Monday morning, and with the earlier possibilities as well, have kept chance PoPs going into the morning Monday, with lesser confidence in precip in the northwest counties nearer the drier low level air. Details in precip activity Monday afternoon will be largely impacted by the earlier activity, but models increase low level moisture further, though NAM likely a bit aggressive again, with CAPE possibly near 2000 J/kg ahead of any outflow or front/effective front. Shear values again look meager to support much severe weather but some potential remains. Have kept highs cooler than today with more cloud/precip/moisture anticipated. .LONG TERM...(Monday Night through Sunday) Issued at 328 PM CDT SUN MAY 3 2015 Models continue to show an active pattern for Monday night through Sunday as they dig another closed low into the southwestern U.S. by the end of the work week. This causes mid level flow to remain from the southwest while gulf moisture continues advecting north. So there looks to be plenty of moisture available with occasional forcing mechanisms passing overhead such that there is a chance for precip in every period of the forecast. The one period with the lowest chance for precip remain Tuesday. There seems to be agreement among the models that shortwave ridge will propagate over eastern KS with some relatively dryer air moving in. Therefore have a dry forecast for northeast and east central KS. North central KS may be close enough to shortwave energy lifting north through the high plains that have kept a small chance for the western counties for Tuesday. The best chance for showers and thunderstorms appears to be late Tuesday night and Wednesday as a well defined shortwave is progged to lift across northeast KS. There are some minor differences in timing of the vort max lifting out. Nevertheless with little or no inhibition to convection expect showers and thunderstorms to overspread the area and have increased POPs into the 70 to 80 percent range. Wednesday night through Saturday does not look like it will be constant precip, but the pattern makes it difficult to say when chances are better than not. With occasional low amplitude waves within the southwest flow and a moist airmass remaining in place, the forecast has a chance for precip each day. There are even some signs of a weak frontal boundary moving into the forecast on Friday which may help focus moisture and provide some lift. Otherwise think chances could be on the increase for Saturday night and Sunday as the upper low begins to lift out of the southern Rockies. Because the GFS is a little further north and doesn`t have as much shortwave energy rotating through the southern plains, have kept POPs in the chance category for now. There should not be any big swings in temps through the period due to the persistent pattern. If anything there may be a slight cool down for Wednesday expecting cloud cover and precip to limit heating. Otherwise temps should be seasonable with lows around 60 and highs in the mid 70s to near 80 && .AVIATION...(For the 06Z TAFs through 06Z Monday Night) Issued at 1143 PM CDT SUN MAY 3 2015 There is a slight chance for showers and storms early this morning although timing and exact location is tough to forecast. It does appear that a portion of the afternoon will remain dry at all of the sites. There is another round possible in the evening which may be closer to MHK. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...65 LONG TERM...Wolters AVIATION...Sanders
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
452 AM EDT MON MAY 4 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 449 AM EDT MON MAY 4 2015 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD SHALLOW TROUGH ACROSS SRN CANADA INTO THE NORTH CENTRAL CONUS. A SHORTWAVE TROUGH LIFTING NE THROUGH NRN ONTARIO WAS DRAGGING A COLD FRONT THROUGH ERN UPPER MICHIGAN. THE PCPN ASSOCIATED WITH THE FRONT AND 700-300 MB QVECTOR CONV AHEAD OF THE MID LEVEL TROUGH HAD MOVED SOUTH AND EAST OF THE CWA. BEHIND THE FRONT...DRIER AIR WAS QUICKLY MOVING INTO UPPER MICHIGAN...PER 00Z KINL SOUNDING...WITH DEWPOINTS DROPPING INTO THE 30S OVER THE NORTH AND WEST. IR LOOP SHOWED MID AND HIGH CLOUDS LINGERING OVER MOST OF UPPER MICHIGAN WITH CLEARING ONLY OVER THE FAR WEST. TODAY...AS HIGH PRES BUILDS FROM THE NRN PLAINS INTO THE WRN GREAT LAKES...EXPECT THE CLOUDS TO DEPART EARLY LEAVING MOSTLY SUNNY SKIES WITH ONLY FEW/SCT CU DEVELOPING. MIXING TO AROUND 5K FEET INLAND WITH 850 MB TEMPS AROUND 5C WILL SUPPORT HIGHS IN THE MID TO UPPER 60S. THE WEAK NRLY WINDS OFF OF LAKE SUPERIOR WILL KEEP READINGS IN THE 50S CLOSER TO THE SHORE. WITH AFTERNOON DEWPOINTS FALLING INTO THE MID TO UPPER 20S...INLAND RH VALUES WILL FALL OFF TO 20 TO 25 PCT. TONIGHT...HIGH PRES WILL DOMINATE KEEPING CONDITIONS DRY MON NIGHT THROUGH TUE. WITH PWATS DROPPING DOWN BELOW.25 INCH AND LIGHT WINDS EXPECTED UNDER THE SFC HIGH...MIN TEMPS NEAR FREEZING ARE EXPECTED AT THE TYPICAL INLAND COLD LOCATIONS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 330 AM EDT MON MAY 4 2015 TUESDAY...SFC HIGH PRESSURE ACROSS LAKE SUPERIOR AND UPPER MI AHEAD OF MID-LEVEL RIDGING OVER THE NORTHERN PLAINS WILL RESULT IN SUNNY SKIES...THOUGH A FEW HIGH CLOUDS MAY FILTER IN THE FROM SE DURING THE AFTERNOON. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...MODELS HAVE TRENDED DOWN A LITTLE BIT ON THE QPF FOR LATE TUE NIGHT INTO WED ALONG AN 850 HPA WARM FRONT/300-310K ISENTROPIC LIFT. WITH STOUT MID-LEVEL RIDGING MOVING OVER THE UPPER MS VALLEY AND OVERALL DEEPER MOISTURE AND LOW- LEVEL MOISTURE TRANSPORT REMAINING CONFINED TO THE WESTERN CWA...KEPT ONLY LOW CHANCE POPS FOR THE WEST HALF. PRECIP CHANCES DIMINISH TO LOW-END SLIGHT CHANCE ACROSS THE WEST WED NIGHT AS THE LOW-LEVEL WAA EXITS TO THE NE AND MID-LEVEL FORCING WELL SW OF THE REGION STRUGGLES TO WORK INTO THE RIDGE. THURSDAY THROUGH FRIDAY...DEEP TROUGHING MOVING ONTO THE PACIFIC NW LATE TODAY WILL HELP KICK A SLOW-MOVING MID-LEVEL TROUGH/LOW ACROSS THE SW STATES BY MID WEEK. THIS WILL CONSOLIDATE A BROAD SFC LOW ACROSS THE WESTERN STATES ON WED. THE LOW IS PROGGED TO TRACK NNE ACROSS THE NORTHERN PLAINS BEFORE BEGINNING TO TURN EASTWARD OVER WESTERN ONTARIO. IT REMAINS TO BE SEEN HOW WELL THE MID-LEVEL TROUGH CAN ERODE THE RIDGE OVER THE UPPER MS VALLEY AND UPPER GREAT LAKES BY THURSDAY. THE ECMWF IS THE MOST PROGRESSIVE WITH THE OVERALL PATTERN...WITH THE TROUGH AND SFC COLD FRONT CLEARING THE CWA BY FRIDAY EVENING. MEANWHILE...THE CANADIAN GEM IS QUITE SLOW...SENDING THE TROUGH WELL NORTH AND WASHING OUT THE COLD FRONT ACROSS THE CWA ON SATURDAY. THE GFS FALLS BETWEEN THESE TWO SOLUTIONS...BUT LEANS TOWARD THE ECMWF. THERE SHOULD BE ENOUGH MID-LEVEL ENERGY TO CHIP AWAY AT THE RIDGE...BUT LIKELY NOT AS FAST AS IS PROGGED BY THE ECMWF. HAVE THEREFORE CHOSEN TO FOLLOW A SOLUTION CLOSE TO THAT OF THE GFS. WITH ALL THAT TAKEN INTO ACCOUNT...SCATTERED SHOWERS AND SOME THUNDERSTORMS SHOULD PUSH INTO THE WESTERN CWA THURSDAY AFTERNOON...AND GRADUALLY SPREAD EASTWARD AS FORCING FROM THE MID- LEVEL WAVE WORKS OVER THE CWA. SCATTERED SHOWERS AND THUNDERSTORMS SHOULD THEN CONTINUE THROUGH MOST OF FRIDAY BEFORE THE COLD FRONT ENDS CHANCES ACROSS THE WEST FRIDAY EVENING. SATURDAY AND SUNDAY...AFTER A LULL IN PRECIP ON SATURDAY...A LARGE PORTION OF THE MAIN WESTERN TROUGH WILL TRACK ACROSS THE PLAINS AND BRING INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS THE CWA FOR SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 151 AM EDT MON MAY 4 2015 EXPECT VFR CONDITIONS AT ALL 3 TAF SITES THIS FCST PERIOD WITH DRY HI PRES BLDG INTO THE UPR LKS. THERE MAY BE SOME GUSTY WINDS AFTER SUNRISE INTO THE EARLY AFTN UNDER THE SHARPER PRES GRADIENT BTWN THE INCOMING HI AND DEPARTING COLD FNT...BUT WINDS SHOULD TREND LIGHTER TOWARD THE END OF THE DAY WITH THE ARRIVAL OF THE WEAKER GRADIENT AS WELL AS LOSS OF DAYTIME HEATING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 449 AM EDT MON MAY 4 2015 FOG IS EXPECTED TO LINGER THIS MORNING OVER THE E HALF OF LAKE SUPERIOR BUT WILL DISSIPATE AS HIGH PRESSURE AND DRIER AIRS BUILDS OVER THE UPPER LAKES FROM THE W-NW TODAY. EXPECT THE HIGH TO DRIFT INTO SE ONTARIO LATER TUESDAY INTO WEDNESDAY...AS ANOTHER AREA OF HIGH PRESSURE MOVES INTO NW ONTARIO...AD A LOW DEVELOPS OVER THE PLAINS. A LOW PRESSURE CENTER WILL MOVE THROUGH THE NRN PLAINS ON THURSDAY WHILE THE ONTARIO HIGH DRIFTS ACROSS HUDSON BAY INTO QUEBEC. THE LOW WILL DRAG A TROUGH ACROSS THE UPPER GREAT LAKES REGION THURSDAY NIGHT THROUGH FRIDAY. ALTHOUGH SRLY WINDS WILL INCREASE FROM THU INTO THU NIGHT...WINDS ARE EXPECTED TO REMAIN AT OR BELOW 20 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KLUBER AVIATION...KC MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
352 AM EDT MON MAY 4 2015 .SHORT TERM... TODAY AND TONIGHT AFTER AN OUTSTANDING WEEKEND OF DRY AND WARM WEATHER...AN ACTIVE PRECIPITATION PATTERN WILL GET UNDERWAY TO START THE WEEK. BEGINNING THIS MORNING...SHOWERS AND A FEW THUNDERSTORMS WILL MARK THE LEADING EDGE OF INCREASED LOW LEVEL MOISTURE ADVANCING THROUGH LOWER MICHIGAN. MORNING COVERAGE WILL BE GREATEST FROM FLINT TO THE TRI CITIES AND NORTHERN THUMB BUT ALL AREAS WILL HAVE AT LEAST A CHANCE OF SHOWERS AS THE MOISTURE SURGE PROGRESSES THROUGH THE REGION. THE COLD FRONT APPROACHING FROM THE WEST WILL THEN TAKE OVER DURING THE AFTERNOON. THAT IS WHEN THE HIGHEST CONCENTRATION OF SHOWERS AND STORMS WILL SHIFT GENERALLY SOUTH OF THE INTERSTATE 69 CORRIDOR THROUGH EARLY EVENING. AFTERNOON THUNDERSTORM POTENTIAL WILL BE STRONGLY DEPENDENT ON RECOVERY OF SURFACE BASED INSTABILITY THAT WILL BE LIMITED BY MORNING CLOUDS AND PRECIPITATION. RADAR OBSERVATIONS INDICATE SHOWERS AND A FEW THUNDERSTORMS EXPANDING IN COVERAGE OVER SW LOWER MICHIGAN SINCE MIDNIGHT. THIS IS OCCURRING ON THE LEADING EDGE OF THE LOW LEVEL MOISTURE AXIS WITH A MODESTLY INCREASING LOW LEVEL JET...BOTH OF WHICH ARE GENERATING A TYPICAL PATTERN OF NOCTURNAL ELEVATED INSTABILITY. THE 00Z MODELS HAVE A REASONABLE HANDLE ON THIS SCENARIO JUDGING BY THETA-E AND WIND FIELDS IN THE 850-700 MB LAYER. PREFER THOSE THAT ARE MORE BULLISH ON THE MAINTENANCE OF MORNING QPF OVER SE MICHIGAN NOW THAT MOISTURE ADVECTION IS PROVING ADEQUATE TO GENERATE CONVECTION. FOR NOW...PLAN TO NUDGE MORNING POPS UP INTO THE CATEGORICAL RANGE IN THE TRI CITIES AND INTO HIGH LIKELY SOUTHWARD ALONG THE U.S. 23 CORRIDOR TO ACCOUNT FOR SOUTHWARD EXPANSION ALONG THE MOISTURE GRADIENT. THERE IS GOOD MODEL AGREEMENT INDICATING THE COLD FRONT IS ON PACE TO BE THROUGH THE TRI CITIES AND NORTHERN THUMB BY EARLY AFTERNOON. EXPECT IT WILL TAKE UNTIL THEN FOR BOUNDARY LAYER TEMPERATURE RECOVERY TO OCCUR ON THE HEELS OF THE MORNING SHOWERS AND CONVECTIVE CLOUD DEBRIS. THIS SUGGESTS LEANING THE FORECAST TOWARD THE LOWER END OF THE MODEL RANGE FOR SURFACE BASED CAPE. THE NAM CONTINUES TO ADVERTISE CAPE REACHING 1500-1800 J/KG SUBJECT TO SURFACE DEWPOINT RISING INTO THE LOWER 60S AS SURFACE TEMPERATURE RECOVERS INTO THE MID TO UPPER 70S. THE RAP AND GFS ALSO INDICATE SURFACE DEWPOINT REACHING THE LOWER 60S BUT PRODUCE CAPE CLOSER TO 1000 J/KG WITH MAIN DIFFERENCE BEING SHALLOWER MID LEVEL LAPSE RATES. THIS IS GENERALLY PREFERRED CONSIDERING THE WARM LARGE SCALE UPPER AIR PATTERN...ESPECIALLY FOR THIS TIME OF YEAR. THE ONE WILD CARD TO MONITOR IS THE HINT OF MCV DEVELOPMENT OVER THE MIDWEST THAT COULD HELP A FEW STORMS OVERACHIEVE. WITH THAT IN MIND...THE SPC OUTLOOK FOR MARGINAL LOOKS REASONABLE BEFORE THE FRONT SETTLES SOUTH OF THE OHIO BORDER BY MIDNIGHT. && .LONG TERM...TUESDAY THROUGH SUNDAY MID LEVEL WESTERLIES TAKE HOLD TUESDAY AND TUESDAY NIGHT ALONG THE NORTHERN PERIPHERY OF SLOWLY EXPANDING SOUTHEAST CONUS UPPER RIDGING. THIS POSITIONING WILL EFFECTIVELY ANCHOR THE SURFACE REFLECTION OF THE EXITING COLD FRONTAL BOUNDARY INVOF OF THE OH/MI BORDER DURING THIS TIME. CONTINUED CONVERGENCE ACROSS THE FRONTAL SLOPE AUGMENTED BY A COMBINATION OF BOTH LOW AMPLITUDE IMPULSES AND/OR REMNANT MCV ACTIVITY AND SOME RENEWED ISENTROPIC LIFT WILL SUPPORT AT LEAST A CHANCE FOR SHOWER DEVELOPMENT. THIS PATTERN PROVIDING THE USUAL CHALLENGES IN DEFINING BOTH POSSIBLE COVERAGE AND TIMING...SOME DEPENDENCE ON HOW NOCTURNAL CONVECTION EXPECTED TO BLOSSOM OVER THE MIDWEST TONIGHT EVENTUALLY SPILLS DOWNSTREAM. GREATER POTENTIAL WILL LIE TOWARD THE SOUTH GIVEN THE FRONTAL POSITIONING AND LESS INFLUENCE FROM DRIER AIR NOSING IN FROM THE NORTH. RIBBON OF HIGHEST THETA-E WILL RESIDE ALONG AND SOUTH OF THE BOUNDARY...BUT OVERALL MOISTURE QUALITY CERTAINLY REMAINS ADEQUATE /PW HOLDING AT 1.3"/. LOW LEVEL ANTICYCLONIC FLOW FILLING ACROSS NORTHERN LOWER MI WILL SUSTAIN A MORE STABLE LOW LEVEL EASTERLY FLOW LOCALLY. THIS WILL KEEP INSTABILITY AT A MINIMUM...CONFINED ABOVE A FIRM INVERSION NOW IN PLACE UP THROUGH 900 MB. THIS EASTERLY FLOW COMBINED WITH A HIGHER DEGREE OF CLOUD COVER AND PROSPECTS FOR SHOWERS TO DISRUPT THE HEATING CYCLE WILL CAP HIGHS IN THE LOWER AND MIDDLE 60S ON TUESDAY. UPPER RIDGE AXIS WILL MOVE ACROSS SE MICHIGAN WEDNESDAY AND WEDNESDAY NIGHT. A SLOWER LOW LEVEL RESPONSE WILL LIKELY RETAIN A LONGER RESIDENCE TIME OF EAST/SE FLOW LOCALLY...LEAVING THE FRONTAL SLOPE DRAPED OVER OR JUST TO THE SOUTHWEST FOR THE BULK OF THE DAYTIME PERIOD. 00Z MODEL GUIDANCE HOLDING WITH JUST VERY LIMITED PRECIPITATION POTENTIAL OWING TO BOTH THE DEGREE OF STABILITY/UPPER RIDGE POSITIONING AND LACK OF SHORTWAVE ENERGY/REMNANT CONVECTIVE DEBRIS TO PROVIDE AN ADDITIONAL FOCUS. CERTAINLY PLAUSIBLE A FEW SHOWERS EMERGE AS WEAK ASCENT PERSISTS ALONG THE ELEVATED FRONTAL SLAB /900-700 MB/...BUT CONFIDENCE REMAINS ON THE LOWER END AND WILL MAINTAIN A LIMITED MENTION AT THIS TIME. THE UPWARD ADJUSTMENT IN HEIGHTS AND GREATER PROSPECTS FOR SOME PEAKS OF SUN WILL NUDGE HIGHS UP A CATEGORY OR TWO RELATIVE TO TUESDAY. HIGHS UPPER 60S TO LOWER 70S. A PERIOD OF DEEPER SOUTHWEST FLOW FOR THE LATTER HALF OF THE WEEK...DICTATED BY HIGH AMPLITUDE TROUGHING ACROSS THE INTERMOUNTAIN WEST AND UPPER RIDGING EDGING TOWARD THE EAST COAST. THIS WILL PROVIDE A MORE NOTEWORTHY INCREASE IN THE TEMPERATURES FOR BOTH THURSDAY AND FRIDAY. HIGHS MAKING A RUN TOWARD THE LOWER 80S BY FRIDAY. WARM/DRY PROFILE WITH NEGLIGIBLE FORCING WILL MINIMIZE CONVECTIVE CHANCES ON THURSDAY. SIMILAR ENVIRONMENT ON FRIDAY PER 00Z GFS BUT ECMWF PROVIDES A PROGRESSIVE SOLUTION RUNNING A LEAD WAVE OVER THE RIDGE AND DRAGGING THE ATTENDANT COLD FRONT INTO THE REGION BY PEAK HEATING. LOWER END CHANCE POPS REMAIN APPROPRIATE TO HIGHLIGHT THE POTENTIAL AND UNCERTAINTY FOR THE NEXT ROUND OF SHOWERS/THUNDERSTORMS DURING THIS TIME WINDOW. && .MARINE... POTENTIAL FOR THUNDERSTORMS ACROSS ALL MARINE AREAS THROUGH TONIGHT AS A COLD FRONT MOVES ACROSS THE REGION. SOUTHWEST WINDS TODAY WILL SHIFT TO NORTHWESTERLY BY EVENING. LIGHT EASTERLY WINDS WILL THEN DEVELOP FOR TUESDAY AND WEDNESDAY AS HIGH PRESSURE BUILDS ACROSS THE NORTHERN GREAT LAKES. && .AVIATION...ISSUED 1159 PM EDT SUN MAY 3 2015 WIDELY SCATTERED SHOWERS WILL WORK INTO KMBS/KFNT LATE TONIGHT INTO MONDAY MORNING IN ADVANCE OF APPROACHING SHORTWAVE AND COLD FRONT. THIS ACTIVITY WILL LIKELY FADE IN THE DIURNAL CONVECTIVE MINIMUM PORTION OF THE DAY AS IT OUTRUNS ANY UPPER SUPPORT. ADDITIONAL SHRAS AND PERHAPS A FEW TSRAS WILL REDEVELOP BY MIDDAY INTO LATE AFTERNOON AND EARLY EVENING AS THE COLD FRONT ITSELF PROGRESSES INTO THE AREA. THIS WILL OCCUR FIRST KMBS/KFNT AND THEN SHIFT SOUTHWARD THROUGH THE REST OF THE AREA 20Z-22Z AND BEYOND UNTIL THE COLD FRONT CLEARS THE TAF SITES IN THE EVENING AND PRECIPITATION CHANCES WANE. FOR DTW...COLD FRONT WILL MOVE INTO AREA LATE IN THE FORECAST AFTER 00Z MONDAY...BUT PREFRONTAL TROUGH WILL BRING SCT SHRAS TO THE TAF SITE BY AFTERNOON. WHILE A TSRA OR TWO ARE POSSIBLE...CONFIDENCE REMAINS LOW GIVEN WEAK/MODEST INSTABILITY. VFR CIGS WILL GIVE WAY TO OCCASIONAL MVFR WITH THIS ACTIVITY...BUT RETURN TO VFR AFTER 02Z AS FROPA OCCURS AND THE FRONT THEN SINKS SOUTH OF THE AREA. //DTW THRESHOLD PROBABILITIES... * MEDIUM FOR CIGS AOB 5000FT MONDAY AFTERNOON AND EVENING. * LOW FOR TSRAS MONDAY AFTERNOON. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...BT LONG TERM....MR MARINE.......MR AVIATION.....DG YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
357 AM CDT Mon May 4 2015 .SHORT TERM: (Today and Tonight) Issued at 330 AM CDT Mon May 4 2015 There are 2 main areas with precipitation potential this morning. The first is from southeast/east central MO eastward into IL where low-mid level warm advection has resulted in spotty showers within the last few hours. The GFS and recent runs of the HRRR suggest this potential will persist until around mid morning. The other area is across northeast MO/west central IL extending into parts of central MO. The frontal convection has in general become less organized with one area from eastern IA into northern IL and another cluster in NW MO. Both regions have generated a pre-frontal cold pool and outflow boundary, but its the western-most area in NW MO that bears the most watching. General movement has been to the southeast and some of the hi-res WRFs want to bring this cluster along with some additional development into north-central/central MO this morning. The current cluster is within a region of moisture convergence along the northern terminus of a 40+ kts southwesterly LLJ and weak elevated CAPE. It should encounter a less favorable enviroment as it moves southeast this morning, primarily after 12z, however forcing may be sufficient for scattered showers and thunderstorms within the area highlighted by the hi-res guidance. Otherwise clouds should thin across the entire area during the later half of the morning and into the early afternoon and when combined with the present WAA regime and temps aloft, this should result in another warm day with well above normal highs in the 80s. There are some discrepencies in the guidance on the southward position of the front this afternoon and evening with the RAP and ECMWF showing a bit more southward position into the northern part of the CWA by 00z, while the remainder of the models keep it near or just south of the MO/IA border. I think it will ooze south into the far northern part of the CWA by late afternoon. Present indications are that heating and continued low-level moistening late morning into afternoon will result in moderate instability along the frontal zone. Good low level convergence along the boundary combined with lift associated with a migrating short wave moving across southern IA/northern MO should result in extensive convective development during the later half of the afternoon spanning from KS across northern MO/southern IA into central IL. I am still thinking that the broad and veering southwesterly LLJ will maintain numberous thunderstorms/clusters during the evening with a decided eastward motion. Although the models suggest the front will shift slightly northward overnight I am not so sure this will happen with rain cooled air maintaining its position. However increased ridging aloft both in the low-mid levels suggest that the forecast of a northward shift in the convection overnight is reasonable. The only noticeable change to the pops tonight is to expand the area of slight chances southward a bit to I-70. The GFS and ECMWF QPFs are a bit far south and well into the warm sector and I would think the majority of the convection will reside along the front and northward into the cool air. Glass .LONG TERM: (Tuesday through Sunday) Issued at 330 AM CDT Mon May 4 2015 Not much has changed in thinking from 24 hours ago with respect to the Tuesday through weekend period. The front will make a decided shift northward on Tuesday as ridging aloft continues to build from the lower TN Valley into the upper MS Valley, while across southern sections of the CWA we continue to see the models generate some light QPF. I`m still not sold on it but will maintain low pops in the slight range given the uncertainty. Tuesday still looks to be another day of above normal temps with highs in the 80s. Flow aloft becomes more south-southwest on Wednesday and a lead impulse within this flow will traverse the western CWA prompting an increased threat of showers and thunderstorms across western MO into central MO. Flow aloft becomes southwesterly by Thursday and this regime persists into the weekend ahead of a upper trof/low migrating from the western U.S. and into the central U.S.. The threat of showers and thunderstorms Thursday into the weekend gradually ramps up and spreads west to east due to the active southwest flow aloft with embedded disturbances, moist unstable warm sector, and slowly encroaching cold front. Above normal temperatures should persist through the extended period. Glass && .AVIATION: (For the 06z TAFs through 06z Monday Night) Issued at 1154 PM CDT Sun May 3 2015 VFR flight conditions are expected to continue to prevail across the area through Monday evening. Scattered thunderstorms are likely to drift south out of Iowa between 09Z-12Z, potentially impacting the KUIN terminal. However, am not confident enough in areal coverage to mention more than vicinity thunder in the TAF at this time. Further south, short-range guidance is hinting that there will be some high-based showers developing over east central Missouri and southwest Illinois around 12Z. Showers should dissipate by mid morning. VFR conditions with gusty southwest flow is expected for Monday late morning through the afternoon. Another round of thunderstorms is expected near a cold front which will dip into northern Missouri. Coverage over northeast Missouri and west central Illinois is again questionable, and much of the activity may stay north of the area. Thunderstorm activity should diminish through the evening. Specifics for KSTL: VFR flight conditions and south-southwest flow will prevail at Lambert. Isolated to widely scattered high based showers look likely to develop around 12Z Monday morning. Think impacts to the airport will be minimal...though if a heavier shower happens to pass over the airport it could briefly drop visibility to MVFR range. Showers should dissipate by 14-15Z. Wind will be in the 200-220 range through much of the period, increasing to around 12kts during the afternoon with gusts to 20kts. There is a slight chance of thunderstorms during the late afternoon, but it`s much more likely that any thunderstorm activity will stay well north of the terminal. Carney && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
425 AM EDT MON MAY 4 2015 .SYNOPSIS... HIGH PRESSURE SYSTEM WILL CONTINUE TO DRIFT SLOWLY OFFSHORE THROUGH EARLY TO MID-WEEK...PROVIDING SUNSHINE AND SEASONABLE MAY TEMPERATURES. A COASTAL LOW IS EXPECTED TO FORM IN THE BAHAMAS MID-WEEK...AND MEANDER ALONG THE SOUTHEAST COAST THROUGH THE END OF THE WEEK AND INTO NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM MONDAY...DRY AND SEASONABLE WEATHER WILL CONTINUE AS HIGH PRESSURE SLIPS FARTHER OFF SHORE WHILE CONTINUING TO RIDGE BACK INTO THE CAROLINAS. THIS WILL PROVIDE A LIGHT RETURN FLOW WITH A SLIGHT INCREASE IN MOISTURE. TEMPS DROPPING EARLY THIS MORNING WILL CREATE SOME VERY SHALLOW FOG BUT OVERALL COLUMN WILL REMAIN VERY DRY WITH ONLY LIMITED LOW LEVEL MOISTURE. A MID TO UPPER RIDGE TRIES TO BUILD OVERHEAD...BUT A SHORTWAVE RIDING DOWN FROM THE NW WILL DISRUPT THIS RIDGE AS IT MOVES SLOWLY OVER THE COASTAL CAROLINAS THROUGH THIS AFTERNOON WITH TROUGH BECOMING STRETCHED OUT ALONG THE COAST TONIGHT. AS THIS SHORTWAVE MOVES THROUGH IT WILL PRODUCE SOME PASSING MID LEVEL CLOUDS. THE LIGHT RETURN FLOW AROUND THE SFC HIGH WILL COMBINE WITH AFTERNOON SEA BREEZE TO GIVE IT A STRONG PUSH INLAND THROUGH THE AFTERNOON. CONVERGENCE ALONG THE SEA BREEZE AND THE WESTERN PERIPHERY OF HIGH PRESSURE WILL HELP BUILD SOME AFTERNOON CU. THE SHORTWAVE SHOULD ACT TO ENHANCE THE VERTICAL GROWTH A BIT...BUT A STRONG SUBSIDENCE INVERSION AROUND 8-9 K FT WILL CAP OFF THE CLOUDS AND LIMIT CHC OF SHWRS. THE HRRR TRIES TO GENERATE A FEW STRAY SHOWERS INLAND THIS AFTERNOON BUT BELIEVE THIS WILL JUST END UP BEING CLUSTERS OF CU. HUGE DIURNAL RANGES WILL CONTINUE WITH TEMPS STARTING OUT IN THE MID 50S THIS MORNING AND REACHING UP TO AROUND 80 EXCEPT SLIGHTLY COOLER AT THE BEACHES. CONTINUED ON SHORE FLOW AROUND HIGH WILL SUPPORT A SLOW RISE IN DEWPOINTS TONIGHT AFTER A DIURNAL DROP THIS AFTERNOON IN DEEPER MIXING. THIS WILL KEEP OVERNIGHT LOWS A FEW DEGREES HIGHER...BUT STILL DOWN TO 55 TO 60 MOST PLACES WITH IDEAL RADIATIONAL COOLING CONDITIONS UNDER CLEAR SKIES AND NEAR CALM WINDS. MAY SEE SOME PATCHY SHALLOW GROUND FOG AGAIN TONIGHT AS TEMPS DROP OUT BUT COLUMN WILL BE VERY DRY ABOVE THE SURFACE. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...BERMUDA HIGH ON TUESDAY WILL RETREAT WEDNESDAY AHEAD OF DISTURBANCE EMERGING FROM THE CARIBBEAN AND THE BAHAMAS. MID LEVEL RIDGING IN PLACE ABOVE THE BERMUDA HIGH TUE WILL MAINTAIN WARM AND DRY CONDITIONS ACROSS THE AREA WITH ONLY PATCHES OF SHALLOW AFTERNOON CU. ONSHORE FLOW WILL CONTINUE KEEPING TEMPS NEAR THE COAST AROUND CLIMO WHILE INLAND AREAS WARM UP A BIT. SECOND HALF OF THE PERIOD STARTS TO GET INTERESTING AS THE SYSTEM EMERGING FROM THE BAHAMAS WILL TRY AND COALESCE INTO A WELL DEFINED LOW. THE GOING WILL INITIALLY BE SLOW AND THE LACK OF STEERING FLOW ALOFT IS LIKELY TO KEEP THE SYSTEM SOUTH OF THE AREA THROUGH THE END OF THE PERIOD. STILL A LOT OF UNCERTAINTY REGARDING THIS SYSTEM AND WHILE IT MAY LEAD TO AN INCREASE IN CLOUD COVER...ESPECIALLY ALONG THE COAST WED NIGHT...DO NOT THINK IT WOULD DIRECTLY AFFECT THE REGION BEFORE THE END OF THE PERIOD. THUS WILL MAINTAIN THE DRY FORECAST WITH HIGHS AROUND CLIMO AND LOWS A BIT ABOVE CLIMO. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 3 AM MONDAY...LONG TERM PERIOD WILL BE DOMINATED BY THE LOW EVOLVING OFF THE SOUTHEAST COAST MID TO LATE WEEK. GUIDANCE CONTINUES TO STRUGGLE WITH THIS SYSTEM...MAINLY DUE TO THE LACK OF ANY REAL STEERING FLOW ALOFT. HOWEVER SOME SOLUTIONS SEEM HARD TO BUY. FOR INSTANCE THE LOW DEEPENING AND MOVING UP THE COAST SEEMS THE LEAST LIKELY OUTCOME GIVEN THE 5H RIDGING TO THE NORTH. DO THINK THE LOW COULD GRADUALLY STRENGTHEN THROUGH THE PERIOD. ALTHOUGH THE WATER TEMPS WITHIN THE GULF STREAM ARE AROUND 80 AND SHEAR SHOULD BE WEAK TO NONEXISTENT THERE ARE SEVERAL FACTORS THAT WOULD LIMIT STRENGTHENING. A LACK OF DIFFLUENCE ALOFT EARLY IN THE PERIOD AND THE LARGE SWATH OF SEA SURFACE TEMPS OUTSIDE THE GULF STREAM IN THE 60S BEING THE BIGGEST. SO WHILE SOME DEVELOPMENT OF THIS SYSTEM IS EXPECTED A FULL BLOWN TROPICAL SYSTEM SEEMS TO BE A LONG SHOT. INSTEAD THE SYSTEM WILL PROBABLY ACQUIRE SOME TROPICAL CHARACTERISTICS BUT REMAIN QUITE WEAK AS IT WANDERS OVER THE WATERS OFF THE SOUTHEAST COAST. WORTH NOTING A LOT OF THE GFS ENSEMBLES TAKE THE WEAK LOW INTO FL OR SOUTHERN GA...SOMETHING WHICH A FAIR NUMBER OF THE MEMBERS HAVE BEEN CONSISTENTLY SHOWING OVER THE LAST FEW DAYS. LOCALLY IMPACTS THROUGH THE PERIOD WILL BE NORTHEAST FLOW...WITH SOME ENHANCEMENT LATER IN THE WEEK AND AN INCREASE IN LOW LEVEL MOISTURE. THIS SHOULD BRING ABOUT AN INCREASE IN PRECIP CHANCES...ESPECIALLY ALONG THE COAST...AS THE WEEK WEARS ON. GIVEN THE LOW CONFIDENCE PLAN TO MAKE ONLY SMALL CHANGES TO THE INHERITED FORECAST WHICH WILL NOW CARRY CHC POP THROUGH THE PERIOD WITH TEMPS NEAR TO SLIGHTLY ABOVE CLIMO. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...NOT MUCH SYNOPTICALLY DIFFERENT FROM YESTERDAY...WITH HIGH PRESSURE OFFSHORE GIVING US SOUTHEAST FLOW. THERE IS FOG POTENTIAL AGAIN OVERNIGHT...MAINLY AFTER 08Z. CRE STANDS THE BEST CHANCE AGAIN...BUT COULD NOT RULE OUT INLAND FOG EITHER. DO NOT THINK WE WILL SEE THE LIFR CONDITIONS THAT WE EXPERIENCED LAST NIGHT. MONDAY...BECOMING VFR AT ALL LOCATIONS WITH CONTINUED SOUTHEAST FLOW...STRONGEST ALONG THE COAST. EXTENDED OUTLOOK...PRE-DAWN MORNING FOG IS POSSIBLE EACH DAY THAT COULD RESULT IN MVFR/IFR CONDITIONS. UNSETTLED WEATHER THURSDAY NIGHT THROUGH SATURDAY WITH A SUBTROPICAL LOW. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM MONDAY...HIGH PRESSURE WILL SHIFT FARTHER OFF SHORE WHILE CONTINUING TO RIDGE BACK INTO THE COASTAL CAROLINAS. THEREFORE EXPECT A VERY LIGHT RETURN FLOW TO CONTINUE BASICALLY OUT OF THE SE-S LESS THAN 10 KTS. SEAS WILL RUN UNDER 3 FT MOST WATERS WITH A A VERY SLOW DECLINE THROUGH TODAY WITH SUCH LIGHT WINDS AND DIMINISHING LONGER PERIOD BACKSWELL FROM LOW MOVING OFF INTO THE DISTANT ATLANTIC WATERS. THE WNA SHOWS LONGER PERIOD SWELLS DROPPING OFF BY NOON TODAY WITH JUST SHORTER PERIOD WIND WAVES DOMINATING ESPECIALLY AS SEA BREEZE DEVELOPS THIS AFTERNOON. A PERSISTENT LIGHT ON SHORE RETURN FLOW WILL CAUSE A SLIGHT RISE IN SEAS THROUGH TONIGHT. OVERALL EXPECT BENIGN SEAS AROUND 2 TO 3 FT OR LESS WITH A SLIGHT SPIKE NEAR SHORE IN AFTERNOON SEA BREEZE. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...BERMUDA HIGH WILL MAINTAIN LIGHT EASTERLY FLOW TUE INTO WED. DURING THE SECOND HALF OF THE PERIOD THE HIGH WILL RETREAT NORTHEAST AS WEAK LOW PRESSURE EMERGES FROM THE BAHAMAS. WINDS WILL BACK TO NORTHEAST FOR WED AND WED NIGHT WITH A SLIGHT BUMP IS SPEED. CONFIDENCE WITH RESPECT TO THE AMOUNT OF STRENGTHENING THE LOW WILL UNDERGO AND ITS LOCATION IS RATHER LOW AND THUS FORECAST CONFIDENCE IS ALSO LOW. FOR NOW KEEPING WIND SPEEDS WED AND WED NIGHT CONFINED TO THE 15 TO 20 KT RANGE BUT HIGHER VALUES ARE POSSIBLE. SEAS 2 TO 3 FT TUE INTO WED SHOULD BUILD LATER WED AS NORTHEAST FLOW INCREASES AND COASTAL LOW STARTS TO BECOME A LITTLE MORE DEFINED. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3 AM MONDAY...MUCH OF THE FORECAST DEPENDS ON THE DETAILS OF THE HYBRID TROPICAL SYSTEM MEANDERING OFF THE SOUTHEAST COAST LATE THIS WEEK. WEAK STEERING FLOW ALOFT HAS SO FAR BEFUDDLED GUIDANCE AND NOT CONFIDENT CLARITY WILL DESCEND UPON THE FORECAST IN THE NEAR TERM. THAT SAID FEEL A FORECAST OF NORTHEAST FLOW IN THE 15 TO 20 KT RANGE IS A GOOD COMPROMISE AND IS IN LINE WITH PREVIOUS FORECASTS. SEAS WILL BUILD ON THE BACK OF EXTENDED NORTHEAST FLOW WITH SOME ZONES LIKELY TO EXCEED 6 FT IN PLACES ON THU AND REMAIN ABOVE 6 FT FRI. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...RGZ SHORT TERM...III LONG TERM...III AVIATION...RGZ/DL
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
438 AM EDT MON MAY 4 2015 .SYNOPSIS... LOW PRESSURE WILL TRACK NORTHEAST INTO QUEBEC TODAY WITH A TRAILING COLD FRONT SINKING SOUTH ACROSS MICHIGAN. THE FRONTAL BOUNDARY WILL APPROACH THE AREA AND STALL THROUGH WEDNESDAY...THEN LIFT BACK AS A WARM FRONT ON THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A SURFACE TROUGH EXTENDS FROM THE PLAINS...ACROSS THE WESTERN GREAT LAKES TOWARDS NORTHERN QUEBEC. SHOWERS AND THUNDERSTORMS HAVE BEEN ONGOING ACROSS THE UPPER MIDWEST OVERNIGHT WHERE SHORTWAVE ENERGY ALOFT IS INTERACTING WITH LOW LEVEL MOISTURE ADVECTION ALONG THIS BOUNDARY. COVERAGE OF THUNDERSTORMS HAS GREATLY DIMINISHED OVER THE LAST HOUR WITH A LIMITED AMOUNT OF INSTABILITY. THE CHALLENGE FOR TODAY IS DETERMINING WHAT EFFECT THE UPSTREAM CONVECTION WILL HAVE ON TIMING OF THUNDERSTORMS MOVING INTO THE AREA. AS OF 4 AM...A LEADING AREA OF SHOWERS WAS LIFTING NORTHEAST ACROSS WESTERN LOWER MICHIGAN WHILE AN OUTFLOW BOUNDARY WAS MOVING SOUTHEAST ACROSS NORTHERN ILLINOIS. AN UPPER LEVEL TROUGH WILL MOVE ACROSS LAKE SUPERIOR TODAY...WITH A WEAK COLD FRONT PUSHING SOUTH ACROSS MICHIGAN THROUGH THIS AFTERNOON. THE RUC SHOWS THE MOISTURE ADVECTION PUSHING INTO NORTHWEST OHIO BETWEEN 13-16Z WHICH COULD RESULT IN SOME LEADING SHOWERS DURING THE LATE MORNING TOWARDS TOLEDO. SHOWERS DURING THE MORNING COULD ALSO BE TRIGGERED BY THE UPSTREAM OUTFLOW BOUNDARY OR PERHAPS THE REMNANTS OF AN MCV FROM THE OVERNIGHT CONVECTION. COVERAGE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE DURING THE AFTERNOON AS LOW LEVEL CONVERGENCE INCREASES WITH THE APPROACHING FRONT. DEWPOINTS WILL START THE DAY IN THE 40S AND WILL MOISTEN AS THE SURFACE TROUGH APPROACHES. THE LOW DEWPOINTS WILL KEEP INSTABILITY ON THE LOWER SIDE UNTIL LATER TODAY. UPPER LEVEL JET REMAINS WELL NORTH OF THE AREA SO SHEAR WILL BE A LIMITING FACTOR FOR STRONGER THUNDERSTORMS. THE STORM PREDICTION CENTER HAS MOST OF NORTHWEST AND NORTH CENTRAL OHIO IN THE MARGINAL THREAT FOR SEVERE WEATHER AS THE FRONT APPROACHES WHICH IS REASONABLE. NOT EXPECTING MORE THAN A COUPLE SOMEWHAT STRONG STORM THOUGH. TWEAKED HIGHS DOWN A DEGREE OR TWO IN NORTHWEST OHIO WHERE CONSIDERABLE CLOUD COVER IS EXPECTED...EVEN THIS MORNING. AREAS FARTHER EAST WILL SEE MORE SUN BEFORE THE CLOUDS ARRIVE. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... WILL CONTINUE WITH LIKELY POPS AS THE FRONT SINKS SOUTH INTO NORTHERN OHIO THIS EVENING. THE PUSH OF MID-LEVEL DRY AIR GETS AS FAR SOUTH AS LAKE ERIE...LEAVING A WEAKENING INSTABILITY AXIS OVERHEAD. THIS SHOULD RESULT IN A DECREASING TREND TO THUNDERSTORMS LATE TONIGHT. THE NEXT ROUND OF SHORTWAVE ENERGY WILL MOVE ALONG THE STALLED FRONTAL BOUNDARY ON TUESDAY AND SHOULD SEE SCATTERED TO NUMEROUS COVERAGE OF SHOWERS AND THUNDERSTORMS AGAIN. LOWERED HIGHS ON TUESDAY ACROSS THE NORTH AS WINDS DEVELOP OFF LAKE ERIE AND SUFFICIENT CLOUD COVER HAS A LIMITING EFFECT ON TEMPERATURES. A FEW OF THE SOUTHERN COUNTIES MAY STILL REACH THE MID 70S. THE RIDGE STARTS TO BUILD ALOFT FROM TUESDAY NIGHT INTO WEDNESDAY WHICH SHOULD BRING AN END TO CONVECTION. WILL HOLD ONTO THE LOW 20-30 PERCENT POPS ON WEDNESDAY WITH SOME UNCERTAINTY ON WHERE THE STALLED FRONTAL BOUNDARY WILL RESIDE AT THAT TIME. BY THURSDAY WE RETURN TO HAVING A DRY FORECAST AS THE CAP STRENGTHENS OVERHEAD. THE WARM FRONT LIFTS BACK EARLY THURSDAY WHICH SUPPORTS HIGHS IN THE MID 70S TO NEAR 80 FOR MUCH OF THE AREA. && .LONG TERM /FRIDAY THROUGH SUNDAY/... UPPER LEVEL RIDGE LOOKS LIKE IT WILL STILL BE IN CONTROL OF THE REGION ON FRIDAY. HOWEVER WITH AN INCREASE IN LOW LEVEL MOISTURE...STRONG HEATING AND THE POTENTIAL OF SOME CONVERGENCE ALONG A LAKE BREEZE AND OVER THE CENTRAL HIGHLANDS WE WILL NEED TO MENTION SOME THUNDER IN THE GRIDS. SINCE HEIGHTS ALOFT ARE RATHER HIGH IT WILL LIMIT THE COVERAGE OF ANY OF THE THUNDER. BY SATURDAY A COLD FRONT WILL MOVE INTO THE CENTRAL GREAT LAKES AND SHOULD BE ENOUGH TO INCREASE THUNDER CHANCES ACROSS THE WEST. A LAKE BOUNDARY MAY ALSO IGNITE A FEW STORMS ACROSS NE OHIO INTO NW PA. THERE SHOULD BE A LULL IN THUNDERSTORM ACTIVITY AFTER MIDNIGHT SATURDAY NIGHT BUT CHANCES WILL INCREASE ON SUNDAY AS THE WEAKENING COLD FRONT PASSES. CURRENT THINKING IS THAT THE COVERAGE WILL BE SCATTERED AT BEST. IT CONTINUES TO LOOK LIKE TEMPERATURES WILL REMAIN ABOVE AVERAGE WITH HIGHS GENERALLY WITHIN A COUPLE DEGREES OF 80. COOLER NEAR THE LAKESHORE. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS WILL CONTINUE UNTIL THUNDERSTORMS DEVELOP THIS AFTERNOON. A COLD FRONT FROM THE UPPER GREAT LAKES TO THE CENTRAL PLAINS WILL MOVE TO THE EAST AND SOUTHEAST THROUGH THE DAY. THUNDERSTORMS HAVE ALREADY DEVELOPED OVER THE UPPER GREAT LAKES AND WILL SPREAD SOME CONVECTIVE DEBRIS CLOUDINESS TO THE REGION FOR TODAY. BELIEVE THE INITIAL SURGE OF SHOWERS/THUNDERSTORMS WILL DECREASE IN COVERAGE AND INTENSITY THIS MORNING AS IT ATTEMPTS TO MOVE INTO NW OHIO. OUTFLOW BOUNDARIES AND THE COLD FRONT WILL PROVIDE LOW LEVEL CONVERGENCE TO GENERATE NEW THUNDERSTORMS EARLY TO MID AFTERNOON. THE THUNDERSTORMS WILL THEN DRIFT TO THE EAST AND SOUTHEAST INTO THE EVENING HOURS. STILL UNCERTAINTY ON WHEN THE CONVECTION WILL DEVELOP AND HAVE A 6 HOUR WINDOW OF TIME WHEN THE THUNDER MAY OCCUR (VCTS). HOWEVER WE DID ATTEMPT TO PROVIDE A BEST 2 HOUR WINDOW FOR CONVECTION FOR EACH LOCATION. THIS 2 HOUR WINDOW IS WHERE WE PLACED THE IFR CONDITIONS. .OUTLOOK...NON VFR POSSIBLE TUESDAY INTO TUESDAY NIGHT IN SCATTERED SHOWERS AND THUNDERSTORMS. && .MARINE... SOUTHWESTERLY WINDS WILL INCREASE AHEAD OF A COLD FRONT THAT WILL MOVE ACROSS LAKE ERIE THIS EVENING. THESE SOUTHWESTERLY WINDS SHOULD BE IN THE 10 TO 20 KNOT RANGE THROUGH THE DAY WITH THE LARGER WAVES OF 2 TO 3 FEET ACROSS THE OPEN WATERS. WINDS AND WAVES WILL DECREASE TONIGHT AS THE COLD FRONT STALLS OVER NORTHERN OR CENTRAL OHIO. HIGH PRESSURE OVER SOUTHERN CANADA WILL PRODUCE NORTHEAST TO EAST WINDS THROUGH THURSDAY. MOST LOCATIONS WILL KEEP WIND SPEEDS IN THE 5 TO 10 KNOT RANGE BUT SOME LOCALLY HIGHER WINDS...MAYBE UP TO 15 KNOTS...ACROSS THE NEARSHORE WATERS WILL LIKELY OCCUR TUESDAY THROUGH THURSDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KEC NEAR TERM...KEC SHORT TERM...KEC LONG TERM...MULLEN AVIATION...MULLEN MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
402 AM CDT MON MAY 4 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 400 AM CDT MON MAY 4 2015 CHALLENGING FORECAST LOOKS TO BEGIN WITH CHALLENGING SHORT TERM. OVERNIGHT...HAVE SEEN THE STRONG SURFACE FRONTAL BOUNDARY SETTLE INTO FAR SOUTHERN PORTIONS OF THE REGION...AS MUCH DRIER AIR HAS INVADED FROM THE NORTH BEHIND THE BOUNDARY. SEVERAL CONTRADICTING FACTORS TO THE SHORT TERM PRECIPITATION FORECAST. FIRST...VERY FEW SOLUTIONS HAVE AMPLE HANDLE ON THE DRY AIR INTRUSION AT LOWEST LEVELS...WITH DEWPOINTS INTO THE UPPER 20S AND 30S OVER ALL BUT THE EXTREME SOUTHEAST CWA. SECOND...THE DEGREE OF ELEVATED INSTABILITY ACROSS THE FAR SOUTHERN CWA IS LACKING IN SHORT TERM HIGH RESOLUTION MODELS...WHICH IS EVIDENT GIVEN RECENT UPTAKE IN SCATTERED BANDED CONVECTION FROM THE LOWER MISSOURI VALLEY EASTWARD ACROSS NORTHWEST IOWA FORCED IN BROAD JET ENTRANCE REGION. THIRD...DEALING WITH TYPICAL BATTLE OF LOWER VERSUS HIGHER RESOLUTION MODELS. LARGE SCALE SYNOPTIC TREND IS FOR LOWER LEVEL BAROCLINIC ZONE TO SETTLE FURTHER SOUTHWARD OVER LAST COUPLE OF MODEL RUNS. HOWEVER...SOME QUESTION AS TO HOW MUCH FURTHER THE MID LEVEL BOUNDARY WILL SETTLE GIVEN THE PROXIMITY OF UPPER LEVEL JET ENTRANCE REGION PASSING ACROSS THE AREA TODAY. HIGHER RESOLUTION MODELS GENERALLY MUCH MORE AGGRESSIVE WITH NORTHWARD SPREAD OF PRECIPITATION. HOWEVER...SHOULD MAKE NOTE THAT TREND IN RAP HAS BEEN TO ALLOW LESS AND LESS THREAT TO SOUTHERN CWA THROUGH THE DAY. EARLY ON THIS MORNING...SHOULD SEE A GRADUAL DECREASE IN THE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE FAR SOUTH EARLY THIS MORNING AS THE WAVE CONTINUES TO SHEAR AWAY. WILL SEE RIDGING BEGIN TO REESTABLISH PRESENCE...BUT BATTLE A SMALL WAVE WANDERING FROM KANSAS TOWARD EASTERN NEBRASKA LATER IN THE DAY. CONVECTION SHOULD BREAK OUT CLOSER TO THIS FEATURE AND THE DEEPER SYNOPTIC BOUNDARY...EXPANDING AND TRENDING TOWARD A MORE EASTWARD MOTION WITH TIME ALONG BAROCLINIC ZONE EXPANDING TOWARD THE SIOUX CITY AREA LATE DAY. GRADUALLY...THIS WAVE PULLS EASTWARD AND MAY SEE MOST EXPANSIVE COVERAGE BRUSH THROUGH THE SOUTHERN CWA DURING THE EVENING HOURS...THEN PROGRESS TOWARD A MORE SCATTERED COVERAGE AS MID LEVEL WAVE AND ISENTROPIC ASCENT PUSHES NORTHWARD WITH DEEPENING SOUTHERLY FLOW. OVERALL...WILL BE LOOKING FOR THUNDER COVERAGE TO BE SMALL FRACTION OF THE OVERALL PRECIPITATION...WITH BEST THREAT THROUGH THE SOUTHEAST HALF OF THE CWA OVERNIGHT. NO SEVERE STORMS ARE EXPECTED WITH MINIMAL ELEVATED INSTABILITY AND GENERALLY WEAK MID LEVEL FLOW. TEMPWISE...WILL SET UP FOR FAIRLY DECENT EASTERLY MIXING WITH DRY AIR...DESPITE A DECENT AMOUNT OF CLOUDINESS MOST LOCATIONS THROUGH THE DAY. HIGHS SHOULD BE MAINLY UPPER 60S TO LOWER 70S...ON THE WARM SIDE OF MIXING POTENTIAL DUE TO THE DRY AIR. INCREASING MOISTURE TONIGHT FROM SOUTH TO NORTH WILL DEFINE LOWS UNDER THICKER CLOUDS...MID 40S NORTH TO LOWER TO MID 50S SOUTH. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 400 AM CDT MON MAY 4 2015 A RATHER MESSY MEDIUM AND EXTENDED FORECAST IS IN STORE FOR THE REGION THIS WEEK AND INTO NEXT WEEKEND. THE LONG WAVE PATTERN WILL BE DOMINATED BY LONG WAVE RIDGING ACROSS THE CONUS THIS WEEK...WITH SEVERAL TROUGHS LIFTING THROUGH THE PLAINS. THE MAIN WEATHER FEATURE THROUGH WEDNESDAY/THURSDAY WILL BE A BROAD UPPER LOW CURRENTLY OVER THE SOUTHWESTERN UNITED STATES THAT IS EXPECTED TO SLIDE ALONG THE WESTERN PERIPHERY OF THE RIDGE. BY TUESDAY...THIS TROUGH WILL BEGIN TO NUDGE THE LOW-LVL BAROCLINIC ZONE NORTHWARD...WITH BROAD ISENTROPIC LIFT BRINING A CHANCE FOR SHOWERS TO THE AREA ON TUESDAY. THE PRIMARY CONCERN WILL BE JUST HOW WIDESPREAD THIS ACTIVITY WILL BE...AS SHORTWAVE ENERGY MOVING THROUGH LATER TONIGHT SLIDES EAST OF THE AREA ON TUESDAY...ONLY TO BE REPLACED BY SHORTWAVE RIDGING. AND ADDITIONAL FACTOR IS THE DEGREE OF DRY AIR REMAINING IN THE SUB-700 MB LAYER. WITH THE LIFT BROAD IN NATURE...AND MOISTURE LIMITED TO A DEGREE...QPF THROUGH TUESDAY NIGHT SHOULD BE FAIRLY LOW. THEN A STRONGER PORTION OF THE AFOREMENTIONED UPPER TROUGH WILL BEGIN TO LIFT INTO THE PLAINS ON WEDNESDAY. MODELS ALL IN GOOD AGREEMENT THAT REMNANT CONVECTION FROM TUESDAY NIGHT ON THE WESTERN PLAINS WILL LIFT INTO THE LOCAL AREA DURING THE DAY ON WEDNESDAY WITH BROAD AND STRONG ISENTROPIC LIFT ASSISTING IN THE DEVELOPMENT OF ADDITIONAL SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY THROUGH THE DAY. MOISTURE TRANSPORT RATHER IMPRESSIVE...BRINGING PWAT VALUES AROUND 1.5 INCHES INTO THE AREA. HOWEVER...A DISTINCT LACK OF INSTABILITY IS ASSOCIATED WITH THIS PRECIPITATION FOR MUCH OF WEDNESDAY...AND THIS SHOULD KEEP QPF DOWN. DEPENDING ON THE SPEED OF PRECIPITATION WEDNESDAY MORNING...WILL NEED TO WATCH FOR THE POTENTIAL OF CLOUDS SCATTERING LATER IN THE AFTERNOON. A SECONDARY ROUND OF CONVECTION WILL LIKELY DEVELOP ALONG INVERTED TROUGH OR DRYLINE ACROSS WESTERN NEBRASKA/KANSAS LATE WEDNESDAY AFTERNOON. ONCE FORMED...IT WILL LIFT NORTHEAST WITH THE SHORTWAVE WEDNESDAY NIGHT. MUCAPE VALUES COULD CLIMB AS HIGH AS 500- 1000 J/KG WEDNESDAY EVENING AND SHEAR WILL BE ON THE INCREASE...MAINLY SOUTH AND WEST OF THE JAMES RIVER. THAT SAID...FEEL THE GENERAL RISK OF SVR STORMS IS LOW...BUT COULD SEE MARGINAL OUTLOOK SLIDE A BIT FURTHER NORTH. I WOULD ANTICIPATE QUITE A BIT OF THUNDER AS THIS ACTIVITY LIFTS THROUGH THE AREA INTO THURSDAY MORNING. FEEL MOST OF THURSDAY WILL BE DRY...AS UPPER FORCING LIFTS NORTHEAST. THE UPPER TROUGH COULD LEAVE AN ELONGATED BOUNDARY ACROSS THE SOUTHERN ZONES BY THURSDAY AFTERNOON. MODELS STILL VARY SIGNIFICANTLY WITH THIS FRONT...BUT A DECENT BUILDUP OF INSTABILITY ALONG AND SOUTH OF IT COULD BE TAPPED INTO SHOULD A WEAK WAVE LIFT NORTHWARD IN THE SWLY FLOW ALOFT. SHEAR CONTINUES TO BE MARGINAL...BUT COULD SUPPORT A SEVERE STORM. FRIDAY MAY BE THE DRIEST DAY OF THE EXTENDED...AS MODELS ARE IN REASONABLE AGREEMENT FORMING A DEEP TROUGH OVER THE WESTERN THIRD OF THE CONUS. BEYOND FRIDAY...BEGINNING TO LOOK RATHER WET ACROSS MANY AREAS AS THIS UPPER TROUGH BEGINS TO LIFT INTO THE PLAINS AND EVENTUALLY GREAT LAKES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 631 PM CDT SUN MAY 3 2015 MAIN FOCUS IS CONVECTION THIS EVENING. FOR KHON...CONDITIONS EXPECTED TO BE VFR THROUGH 00Z TUE. FOR KFSD...ALSO EXPECTING VFR CONDITIONS THROUGH PERIOD WITH WINDS DROPPING OFF TO 10 TO 15 KTS AFTER 02Z. SMALL CONCERN THAT HIGH RES MODELS ARE SHOWING SOME CONVECTION DEVELOPING BETWEEN 03Z AND 06Z AND NAM/GFS SOUNDINGS DO SHOW INSTABILITY ABOVE 800 MB. AT THIS POINT...PROBABILITY IS TOO LOW TO INCLUDE IN TAF BUT WILL NEED TO MONITOR FOR STORMS LATER TONIGHT. FOR KSUX...IN GENERAL VFR CONDITIONS EXPECTED. THERE IS A CHANCE OF STORMS THIS EVENING ALTHOUGH NO EVIDENCE ON SATELLITE OR RADAR THAT STORMS ARE IMMINENT SO HAVE WILL NOT INCLUDE IN TAF AT THIS TIME. OTHERWISE...SIMILAR ISSUE TO KFSD IN THAT HI-RES MODELS MOVE THESE STORMS NEAR KSUX BETWEEN 05Z AND 09Z TONIGHT. AGAIN...PROBABILITY TOO LOW TO INCLUDE IN TAF. NEXT ROUND OF RAIN WILL BE APPROACHING KSUX AROUND 00Z. AT THIS POINT...BETTER CHANCES AFTER 00Z TUESDAY SO KEPT CONDITIONS VFR. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHAPMAN LONG TERM...DUX AVIATION...SCHUMACHER
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
356 AM MDT MON MAY 4 2015 .SYNOPSIS... AN UPPER LOW WILL MOVE TO ARIZONA THIS AFTERNOON AND ACROSS NORTHERN NEW MEXICO ON TUESDAY. THIS WILL ALLOW ISOLATED SHOWERS AND THUNDERSTORMS TO CONTINUE TODAY AND TONIGHT. THE LOW MOVING ACROSS NEW MEXICO TUESDAY WILL ALLOW MOISTURE TO DIMINISH...WITH JUST A SLIGHT CHANCE FOR THUNDERSTORMS OVER THE MOUNTAINS. TEMPERATURES WILL RUN AT TO SLIGHTLY ABOVE NORMAL. WEDNESDAY INTO THE WEEKEND A DRY SOUTHWEST FLOW ALOFT WILL DEVELOP AND KEEP THE AREA DRY. AFTERNOONS WILL BECOME BREEZY...BUT DESPITE THIS...TEMPERATURES WILL REMAIN NEAR NORMAL. && .DISCUSSION... UPPER LOW NOW JUST OFF THE SOUTHERN CALIFORNIA COAST. HAS NOT BEGUN TO ENTRAIN MUCH MOISTURE SO HARD TO SEE. DRY SLOW CONTINUES OVER THE AREA BUT SO DOES A 130 KT JET WITH WEAK DISTURBANCES. THIS SHOULD BE GOOD ENOUGH FOR ANOTHER ROUND OF SHOWERS/THUNDERSTORMS TODAY AND TONIGHT. WINDS LIKELY MAIN HAZARD AGAIN. LATEST HRRR SHOWS DCAPES OF UP TO 850 J/KG. DEW POINT DEPRESSIONS SLIGHTLY LESS THAN SUNDAY BUT STILL AROUND 50 DEGREES THIS AFTERNOON. WIND GUST POTENTIAL LOOKS TO BE 40-50 MPH WITH ANY STORMS/SHOWERS. LACK OF DEEP MOISTURE AND/OR HIGH DEW POINTS SHOULD PRECLUDE HEAVY RAINFALL...MAYBE .25 - .50 INCHES WITH THUNDERSTORMS. UPPER LOW TO WESTERN NEW MEXICO TUESDAY MID DAY AND THEN OVER THE COLORADO ROCKIES BY TUESDAY EVENING. THIS LOW PASSAGE AND WEAK PACIFIC SURFACE FRONT WILL HELP TO SCOUR OUT MOISTURE SOME. MODELS STILL SHOWING JUST ENOUGH RESIDUAL MOISTURE AND INSTABILITY TO KICK OFF A FEW THUNDERSTORMS OVER THE MOUNTAIN ZONES. OTHERWISE POPS OUT FOR THE REST OF THE FORECAST PERIOD...AS DRY SOUTHWEST FLOW ALOFT AHEAD OF A WEST COAST UPPER TROUGH DEVELOPS AND PERSISTS INTO THE WEEKEND. AFTERNOONS WILL BECOME BREEZY TO WINDY THURSDAY THROUGH SATURDAY. DESPITE THIS PATTERN HIGH TEMPS SHOULD REMAIN AT OR SLIGHTLY ABOVE NORMAL. && .AVIATION...VALID 04/12Z-05/12Z... VFR CONDITIONS SHOULD PERSIST AT ALL TAF SITES THRU THE PERIOD. WEAK DISTURBANCES WILL RESULT IN ANOTHER ROUND OF HIGH BASED SHOWER ACTIVITY DEVELOPING AFTER 20Z WITH 26015G25KT SCT-BKN080-100 PREVAILING. -TSRA SCT-BKN080CB POSSIBLE OVER HIGHER TERRAIN AND AT KTCS DURING THE AFTERNOON AND EARLY EVENING. && .FIRE WEATHER... A FEW WEAK DISTURBANCES ALOFT WILL MOVE PAST THE REGION TODAY AND TONIGHT AS AN UPPER LOW TRACKS EAST FROM THE COAST OF SOUTHERN CALIFORNIA. THIS WILL BRING ANOTHER ROUND OF MAINLY HIGH BASED SHOWER ACTIVITY TO THE FIRE ZONES. INITIALLY MOST OF THE SHOWERS WILL EVAPORATE BEFORE REACHING THE SURFACE WHICH WILL PRODUCE LOCALLY GUSTY WINDS. THE BEST CHANCE FOR ACTUAL WETTING PRECIP WILL BE OVER THE HIGHER TERRAIN OF THE NORTH AS WELL AS THE FAR EASTERN FIRE ZONES THIS AFTERNOON AND EVENING. MIN RH VALUES WILL RUN ABOUT 2O PERCENT FOR THE LOWLANDS AND 30 PERCENT FOR THE MOUNTAINS TODAY. AS DEEP WESTERLY FLOW DEVELOPS TUESDAY MIN RH VALUES WILL DROP ABOUT 5 PERCENT WITH AN ADDITIONAL 5 PERCENT DECLINE FOR THE REST OF THE WEEK AHEAD. AS ANOTHER STRONGER UPPER STORM APPROACHES LATE WEEK STRONGER AFTERNOON SURFACE WINDS WILL DEVELOP WHICH COULD LEAD TO SOME FIRE WEATHER CONCERNS FOR THE THURSDAY THRU SATURDAY PERIOD. && .PRELIMINARY POINT TEMPS/POPS... EL PASO 86 60 82 58 85 / 10 10 0 0 0 SIERRA BLANCA 83 54 82 54 84 / 10 20 0 0 0 LAS CRUCES 83 51 81 50 84 / 10 10 0 0 0 ALAMOGORDO 83 54 81 53 84 / 20 30 0 0 0 CLOUDCROFT 62 42 60 39 62 / 50 30 30 0 0 TRUTH OR CONSEQUENCES 81 50 79 50 82 / 20 20 10 0 0 SILVER CITY 73 46 69 46 72 / 20 20 20 0 0 DEMING 83 48 81 48 84 / 10 10 0 0 0 LORDSBURG 81 48 80 48 82 / 20 10 10 0 0 WEST EL PASO METRO 85 60 82 59 85 / 10 10 0 0 0 DELL CITY 85 54 81 52 84 / 20 30 20 0 0 FORT HANCOCK 87 56 83 55 87 / 10 20 0 0 0 LOMA LINDA 79 58 78 57 79 / 10 20 0 0 0 FABENS 86 55 82 54 85 / 10 20 0 0 0 SANTA TERESA 85 55 82 54 85 / 10 10 0 0 0 WHITE SANDS HQ 82 58 81 57 83 / 20 20 0 0 0 JORNADA RANGE 83 50 81 48 83 / 20 10 0 0 0 HATCH 83 50 82 49 84 / 20 10 0 0 0 COLUMBUS 81 54 81 53 83 / 10 10 0 0 0 OROGRANDE 84 57 82 57 83 / 20 20 0 0 0 MAYHILL 71 48 70 46 71 / 50 40 30 0 0 MESCALERO 71 45 70 43 70 / 50 40 30 0 0 TIMBERON 70 47 69 45 70 / 50 30 20 0 0 WINSTON 69 44 72 41 73 / 30 20 30 0 0 HILLSBORO 78 48 78 47 80 / 20 20 20 0 0 SPACEPORT 82 49 81 48 83 / 20 20 0 0 0 LAKE ROBERTS 72 44 70 42 72 / 30 20 30 0 0 HURLEY 74 47 70 45 73 / 10 20 20 0 0 CLIFF 80 42 76 42 80 / 20 10 30 0 0 MULE CREEK 76 39 74 40 78 / 20 10 30 0 0 FAYWOOD 75 47 75 47 78 / 10 20 20 0 0 ANIMAS 80 48 81 49 83 / 20 10 0 0 0 HACHITA 81 47 81 48 83 / 10 10 0 0 0 ANTELOPE WELLS 80 46 80 48 82 / 10 10 0 0 0 CLOVERDALE 76 47 76 48 78 / 10 0 0 0 0 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...NONE. TX...NONE. && $$ HEFNER/LANEY
AREA FORECAST DISCUSSION
NWS ALBANY NY
1044 AM EDT MON MAY 4 2015 .SYNOPSIS... PLENTY OF SUNSHINE AND A MILD SOUTHWESTERLY FLOW WILL ALLOW FOR ABOVE NORMAL TEMPERATURES TODAY. AN APPROACHING COLD FRONT WILL BRING THE CHANCE FOR SOME SHOWERS TONIGHT INTO TOMORROW MORNING...WITH AN ISOLATED RUMBLE OF THUNDER ALSO POSSIBLE. DRY WEATHER WILL RETURN FOR THE REST OF THE WEEK...ALONG WITH CONTINUED ABOVE NORMAL TEMPERATURES. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1044 AM EDT...ISSUED RED FLAG WARNING FOR SOUTHERN VERMONT BASED ON USER REQUEST. RFW IS VALID FROM 12 PM TO 8 PM. ALL OF ALBANY FORECAST AREA NOW HAS A RED FLAG WARNING EXCEPT LITCHFIELD COUNTY CT. HIGH PRESSURE STRETCHES FROM THE SOUTHERN APPALACHIANS TO JUST SOUTHEAST OF CAPE COD...WHILE A SFC COLD FRONT REMAINS WELL UPSTREAM OVER THE WESTERN GREAT LAKES. VISIBLE SATELLITE IMAGERY SHOWS CLEAR TO PARTLY CLOUDY SKIES OVER THE REGION...WITH JUST SOME PASSING CLOUDS OVER THE WESTERN ADIRONDACKS AND ANOTHER PATCH THAT EXTENDS FROM THE EASTERN MOHAWK VALLEY SOUTH ACROSS THE EASTERN CATSKILLS AND EASTWARD ACROSS THE MID HUDSON VALLEY INTO LITCHFIELD COUNTY. WINDS ARE FROM THE SOUTH TO SOUTHWEST. SOME MID AND HIGH LEVEL CLOUDS SHOULD START TO INCREASE LATE IN THE DAY AS THE UPSTREAM COLD FRONT STARS TO APPROACH...BUT IT LOOKS DRY FOR MOST OF THE AREA THROUGH AT LEAST THE EARLY EVENING HOURS. LATEST HRRR HAS SOME SHOWERS REACHING NORTHERN HERKIMER AND HAMILTON COUNTIES BETWEEN 5 AND 7 PM. SLIGHT CHANCE POPS FOR THE WESTERN ADIRONDACKS. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... THE COLD FRONT LOOKS TO MOVE ACROSS THE REGION TONIGHT INTO TUESDAY...AND SLOWLY DRIFT TO THE SOUTH THROUGH THE REMAINDER OF THE SHORT TERM PERIOD. AS A RESULT...SOME RAIN SHOWERS WILL BE POSSIBLE FOR TONIGHT INTO TUESDAY. THERE WON/T BE A LOT OF MOISTURE ASSOCIATED WITH THIS BOUNDARY...AND SHOWERS WON/T BE OVERLY WIDESPREAD. MOST AREAS WILL ONLY SEE A FEW PASSING LIGHT SHOWERS WITH THE COLD FRONTAL PASSAGE. BEST CHANCE FOR SEEING RAINFALL LOOKS NORTH AND WEST OF THE CAPITAL REGION. CLOUDS WILL INCREASE THIS EVENING...AND IT WILL BE FAIRLY CLOUDY INTO THE START OF TUESDAY. TEMPS OVERNIGHT WITH THE CLOUDS/SHOWERS WILL BE MILD WITH UPPER 40S TO UPPER 50S ACROSS THE REGION. SKIES WILL GRADUALLY CLEAR FROM NORTH TO SOUTH THROUGH THE DAY TUESDAY...ALTHOUGH SOUTHERN AREAS /CATSKILLS...MID HUDSON VALLEY...NW CT/ MAY WIND UP STAYING CLOUDY WITH A CHANCE OF SHOWERS THROUGH THE ENTIRE DAY TUESDAY AND INTO TUESDAY EVENING. TEMPS ON TUESDAY WILL STILL BE MILD...ALTHOUGH NOT QUITE AS WARM AS MONDAY...WITH HIGHS IN THE 70S. WITH THE FRONT JUST SOUTH OF THE AREA...THERE STILL MAY BE A LINGERING SHOWER AND SOME CLOUDS FOR FAR SOUTHERN AREAS ON TUESDAY NIGHT...BUT MOST AREAS WILL SEE A PARTLY TO MOSTLY CLEAR SKY ON TUESDAY NIGHT WITH DRY WEATHER. TEMPS WILL RANGE FROM THE 30S IN THE ADIRONDACKS TO THE UPPER 40S IN THE MID HUDSON VALLEY WHERE MORE CLOUDS WILL REMAIN. HIGH PRESSURE LOOKS TO BUILD IN FOR WEDNESDAY THROUGH WEDNESDAY NIGHT WITH MOSTLY CLEAR SKIES AS THE COLD FRONT FINALLY DRIFTS SOUTHWARD TOWARDS THE MID ATLANTIC REGION. DESPITE BEING BEHIND THE COLD FRONT...DAYTIME TEMPS WILL STILL BE QUITE WARM...WITH HIGHS ON WEDNESDAY BEING IN THE UPPER 60S TO UPPER 70S. MIN TEMPS ON WED NIGHT WILL GENERALLY BE IN THE 40S...ALTHOUGH A FEW 30S ARE POSSIBLE FOR THE HIGHER ELEVATIONS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... MODEL GUIDANCE IS IN GENERAL AGREEMENT THAT THE LONGWAVE PATTERN WILL FEATURE A RIDGE OVER THE NORTHEASTERN UNITED STATES WITH A TROUGH OVER THE WESTERN UNITED STATES FOR THE LATTER PART OF THE WEEK SHIFTING TO THE OVER THE PLAINS OVER THE WEEKEND. WHILE OFF THE SOUTHEAST COAST...AN AREA OF LOW PRESSURE UNDERNEATH THE RIDGE REMAIN NEARLY STATIONARY OFF THE COAST. DRY AND WARM WEATHER IS EXPECTED FOR THURSDAY AND FRIDAY. HOWEVER AS WE HEAD THROUGH MOTHER`S DAY WEEKEND THERE WILL BE INCREASING CHANCES FOR SOME SHOWERS AS A COLD FRONTAL BOUNDARY APPROACHES FROM THE GREAT LAKES REGION AND DEW POINTS RISE. THE REGION WILL BE IN THE WARM SECTOR OF THE APPROACHING SYSTEM SO ABOVE NORMAL TEMPERATURES ARE EXPECTED TO CONTINUE AS THE BOUNDARY APPROACHES. 850 MB TEMPERATURES ARE FORECAST TO WARM TO 12-15C OVER THE WEEKEND. OVERALL LOOKING FOR TEMPERATURES TO RUN 10 TO 15 DEGREES ABOVE NORMAL. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... THE HIGH PRESSURE OVER THE REGION WILL SHIFT TO THE SOUTHEAST OF THE AREA TODAY AS A COLD FRONT GRADUALLY APPROACHES FROM THE GREAT LAKES REGION. FEW TO SCATTERED MID LEVEL CLOUDS WILL CONTINUE TO MOVE ACROSS THE AREA THIS MORNING. CLOUDS WILL BE ON THE INCREASE TODAY ESPECIALLY THIS AFTERNOON INTO THE EVENING AS THE COLD FRONT MOVES CLOSER TO THE AREA. CHANCES FOR SHOWERS WILL BE IN THE INCREASE AS THE BOUNDARY MOVES INTO AND THROUGH THE AREA. HAVE ADDRESSED THREAT WITH VICINITY SHOWERS IN TAFS. SOUTH TO SOUTHWESTERLY FLOW WILL DEVELOP THIS MORNING AND WILL INCREASE IN SPEED AND BECOME GUSTY AS THE MORNING PROGRESSES. THE WINDS WILL WEAKEN SOME DURING THE EVENING LOSING THEIR GUSTINESS. WINDS WILL SHIFT TO WEST-NORTHWEST WITH THE PASSAGE OF THE BOUNDARY. OUTLOOK... TUESDAY: LOW OPERATIONAL IMPACT. SLIGHT CHC -SHRA. TUESDAY NIGHT-FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX. && .FIRE WEATHER... A RED FLAG WARNING HAS BEEN ISSUED AT THE REQUEST OF THE NEW YORK STATE DEC FOREST RANGERS AND EMERGENCY MANAGEMENT AND THE MASSACHUSETTS DEPARTMENT OF CONSERVATION AND RECREATION. ALTHOUGH RED FLAG WARNINGS HAVE NOT BEEN ISSUED FOR SOUTHERN VERMONT AND NORTHWESTERN CONNECTICUT...LOCALIZED FIRE WEATHER ISSUES ARE POSSIBLE IN THOSE AREAS AS WELL. SIGNIFICANT RAINFALL /GREATER THAN A QUARTER OF AN INCH/ HAS NOT OCCURRED IN WELL OVER A WEEK ACROSS THE REGION AND STATE OFFICIALS HAVE NOTED THAT FOREST FUELS ARE RATHER DRY AT THIS TIME. RH VALUES ARE EXPECTED TO FALL TO 25 TO 30 PERCENT THIS AFTERNOON...AND S-SW WINDS OF 10 TO 15 MPH WITH SOME HIGHER GUSTS ARE EXPECTED...ALONG WITH AFTERNOON TEMPERATURES IN THE MID 70S TO MID 80S. AS A RESULT...ANY FIRES MAY BECOME DIFFICULT TO CONTROL THIS AFTERNOON INTO THIS EVENING. SPC HAS PLACED MUCH OF THE NORTHEAST IN AN ELEVATED FIRE WEATHER RISK AREA. RH VALUES ARE EXPECTED TO RECOVER TO 90 TO 100 PERCENT TONIGHT WITH SOME RAIN SHOWERS POSSIBLE. RAIN SHOWERS ARE EXPECTED TO BE LIGHT...AND MOST AREAS WON/T SEE A QUARTER OF AN INCH OF RAINFALL. WEST WINDS WILL BE AT 5 T0 15 MPH. WITH RAIN SHOWERS ENDING...AND SKIES STARTING TO CLEAR OUT...RH VALUES ON TUESDAY WILL FALL TO 30 TO 50 PERCENT...WITH THE LOWEST VALUES OVER THE ADIRONDACKS AND SRN VT. HOWEVER...WINDS WILL BE LIGHTER ON TUESDAY...WITH NW WINDS OF 5 TO 10 MPH. DRY WEATHER IS EXPECTED THROUGH THE REMAINDER OF THE WEEK...WITH RH VALUES DROPPING TO NEAR 30 PERCENT EACH AFTERNOON. HOWEVER...WINDS ARE EXPECTED TO BE FAIRLY LIGHT FOR THE REST OF THE WEEK. && .HYDROLOGY... NO HYDROLOGIC ISSUES ARE ANTICIPATED OVER THE NEXT FIVE DAYS. DRY WEATHER WILL BE IN PLACE TODAY WITH ABOVE NORMAL TEMPERATURES. A COLD FRONT WILL BRING SOME LIGHT RAIN SHOWERS TO THE REGION TONIGHT INTO TOMORROW. THE BEST CHANCE WILL BE FOR AREAS NORTH AND WEST OF THE CAPITAL REGION. BASIN AVERAGE RAINFALL WILL GENERALLY ONLY BE A TENTH OR TWO TENTH OF AN INCH. WITH VEGETATION STARTING TO GREEN UP OVER THE AREA...THIS RAINFALL WILL HAVE LITTLE TO NO IMPACT ON AREA RIVERS AND STREAMS. DRY WEATHER WILL BE IN PLACE FOR TUESDAY NIGHT THROUGH THE REMAINDER OF THE WEEK. AS A RESULT...RIVERS AND STREAMS WILL EITHER HOLD STEADY OR SLOWLY RECEDE THROUGH THE WEEK. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEB SITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR NYZ032-033- 038>043-047>054-058>061-063>066-082>084. MA...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR MAZ001-025. VT...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR VTZ013>015. && $$ SYNOPSIS...SND/FRUGIS NEAR TERM...SND SHORT TERM...FRUGIS LONG TERM...IAA AVIATION...IAA FIRE WEATHER...FRUGIS HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1003 AM EDT MON MAY 4 2015 .SYNOPSIS... PLENTY OF SUNSHINE AND A MILD SOUTHWESTERLY FLOW WILL ALLOW FOR ABOVE NORMAL TEMPERATURES TODAY. AN APPROACHING COLD FRONT WILL BRING THE CHANCE FOR SOME SHOWERS TONIGHT INTO TOMORROW MORNING...WITH AN ISOLATED RUMBLE OF THUNDER ALSO POSSIBLE. DRY WEATHER WILL RETURN FOR THE REST OF THE WEEK...ALONG WITH CONTINUED ABOVE NORMAL TEMPERATURES. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1003 AM EDT...MAIN CHANGE TO GRIDS IN THIS UPDATE IS TO ADD SLIGHT CHANCE THUNDER FOR LATE TODAY INTO TOMORROW MORNING AHEAD OF APPROACHING COLD FRONT. HIGH PRESSURE STRETCHES FROM THE SOUTHERN APPALACHAINS TO JUST SOUTHEAST OF CAPE COD...WHILE A SFC COLD FRONT REMAINS WELL UPSTREAM OVER THE WESTERN GREAT LAKES. VISIBLE SATELLITE IMAGERY SHOWS CLEAR TO PARTLY CLOUDY SKIES OVER THE REGION...WITH JUST SOME PASSING CLOUDS OVER THE WESTERN ADIRONDACKS AND ANOTHER PATCH THAT EXTENDS FROM THE EASTERN MOHAWK VALLEY SOUTH ACROSS THE EASTERN CATSKILLS AND EASTWARD ACROSS THE MID HUDSON VALLEY INTO LITCHFIELD COUNTY. WINDS ARE FROM THE SOUTH TO SOUTHWEST. SOME MID AND HIGH LEVEL CLOUDS SHOULD START TO INCREASE LATE IN THE DAY AS THE UPSTREAM COLD FRONT STARS TO APPROACH...BUT IT LOOKS DRY FOR MOST OF THE AREA THROUGH AT LEAST THE EARLY EVENING HOURS. LATEST HRRR HAS SOME SHOWERS REACHING NORTHRN HERKIMER AND HAMILTON COUNTIES BETWEEN 5 AND 7 PM. SLIGHT CHANCE POPS FOR THE WESTERN ADIRONDACKS. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... THE COLD FRONT LOOKS TO MOVE ACROSS THE REGION TONIGHT INTO TUESDAY...AND SLOWLY DRIFT TO THE SOUTH THROUGH THE REMAINDER OF THE SHORT TERM PERIOD. AS A RESULT...SOME RAIN SHOWERS WILL BE POSSIBLE FOR TONIGHT INTO TUESDAY. THERE WON/T BE A LOT OF MOISTURE ASSOCIATED WITH THIS BOUNDARY...AND SHOWERS WON/T BE OVERLY WIDESPREAD. MOST AREAS WILL ONLY SEE A FEW PASSING LIGHT SHOWERS WITH THE COLD FRONTAL PASSAGE. BEST CHANCE FOR SEEING RAINFALL LOOKS NORTH AND WEST OF THE CAPITAL REGION. CLOUDS WILL INCREASE THIS EVENING...AND IT WILL BE FAIRLY CLOUDY INTO THE START OF TUESDAY. TEMPS OVERNIGHT WITH THE CLOUDS/SHOWERS WILL BE MILD WITH UPPER 40S TO UPPER 50S ACROSS THE REGION. SKIES WILL GRADUALLY CLEAR FROM NORTH TO SOUTH THROUGH THE DAY TUESDAY...ALTHOUGH SOUTHERN AREAS /CATSKILLS...MID HUDSON VALLEY...NW CT/ MAY WIND UP STAYING CLOUDY WITH A CHANCE OF SHOWERS THROUGH THE ENTIRE DAY TUESDAY AND INTO TUESDAY EVENING. TEMPS ON TUESDAY WILL STILL BE MILD...ALTHOUGH NOT QUITE AS WARM AS MONDAY...WITH HIGHS IN THE 70S. WITH THE FRONT JUST SOUTH OF THE AREA...THERE STILL MAY BE A LINGERING SHOWER AND SOME CLOUDS FOR FAR SOUTHERN AREAS ON TUESDAY NIGHT...BUT MOST AREAS WILL SEE A PARTLY TO MOSTLY CLEAR SKY ON TUESDAY NIGHT WITH DRY WEATHER. TEMPS WILL RANGE FROM THE 30S IN THE ADIRONDACKS TO THE UPPER 40S IN THE MID HUDSON VALLEY WHERE MORE CLOUDS WILL REMAIN. HIGH PRESSURE LOOKS TO BUILD IN FOR WEDNESDAY THROUGH WEDNESDAY NIGHT WITH MOSTLY CLEAR SKIES AS THE COLD FRONT FINALLY DRIFTS SOUTHWARD TOWARDS THE MID ATLANTIC REGION. DESPITE BEING BEHIND THE COLD FRONT...DAYTIME TEMPS WILL STILL BE QUITE WARM...WITH HIGHS ON WEDNESDAY BEING IN THE UPPER 60S TO UPPER 70S. MIN TEMPS ON WED NIGHT WILL GENERALLY BE IN THE 40S...ALTHOUGH A FEW 30S ARE POSSIBLE FOR THE HIGHER ELEVATIONS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... MODEL GUIDANCE IS IN GENERAL AGREEMENT THAT THE LONGWAVE PATTERN WILL FEATURE A RIDGE OVER THE NORTHEASTERN UNITED STATES WITH A TROUGH OVER THE WESTERN UNITED STATES FOR THE LATTER PART OF THE WEEK SHIFTING TO THE OVER THE PLAINS OVER THE WEEKEND. WHILE OFF THE SOUTHEAST COAST...AN AREA OF LOW PRESSURE UNDERNEATH THE RIDGE REMAIN NEARLY STATIONARY OFF THE COAST. DRY AND WARM WEATHER IS EXPECTED FOR THURSDAY AND FRIDAY. HOWEVER AS WE HEAD THROUGH MOTHER`S DAY WEEKEND THERE WILL BE INCREASING CHANCES FOR SOME SHOWERS AS A COLD FRONTAL BOUNDARY APPROACHES FROM THE GREAT LAKES REGION AND DEW POINTS RISE. THE REGION WILL BE IN THE WARM SECTOR OF THE APPROACHING SYSTEM SO ABOVE NORMAL TEMPERATURES ARE EXPECTED TO CONTINUE AS THE BOUNDARY APPROACHES. 850 MB TEMPERATURES ARE FORECAST TO WARM TO 12-15C OVER THE WEEKEND. OVERALL LOOKING FOR TEMPERATURES TO RUN 10 TO 15 DEGREES ABOVE NORMAL. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... THE HIGH PRESSURE OVER THE REGION WILL SHIFT TO THE SOUTHEAST OF THE AREA TODAY AS A COLD FRONT GRADUALLY APPROACHES FROM THE GREAT LAKES REGION. FEW TO SCATTERED MID LEVEL CLOUDS WILL CONTINUE TO MOVE ACROSS THE AREA THIS MORNING. CLOUDS WILL BE ON THE INCREASE TODAY ESPECIALLY THIS AFTERNOON INTO THE EVENING AS THE COLD FRONT MOVES CLOSER TO THE AREA. CHANCES FOR SHOWERS WILL BE IN THE INCREASE AS THE BOUNDARY MOVES INTO AND THROUGH THE AREA. HAVE ADDRESSED THREAT WITH VICINITY SHOWERS IN TAFS. SOUTH TO SOUTHWESTERLY FLOW WILL DEVELOP THIS MORNING AND WILL INCREASE IN SPEED AND BECOME GUSTY AS THE MORNING PROGRESSES. THE WINDS WILL WEAKEN SOME DURING THE EVENING LOSING THEIR GUSTINESS. WINDS WILL SHIFT TO WEST-NORTHWEST WITH THE PASSAGE OF THE BOUNDARY. OUTLOOK... TUESDAY: LOW OPERATIONAL IMPACT. SLIGHT CHC -SHRA. TUESDAY NIGHT-FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX. && .FIRE WEATHER... A RED FLAG WARNING HAS BEEN ISSUED AT THE REQUEST OF THE NEW YORK STATE DEC FOREST RANGERS AND EMERGENCY MANAGEMENT AND THE MASSACHUSETTS DEPARTMENT OF CONSERVATION AND RECREATION. ALTHOUGH RED FLAG WARNINGS HAVE NOT BEEN ISSUED FOR SOUTHERN VERMONT AND NORTHWESTERN CONNECTICUT...LOCALIZED FIRE WEATHER ISSUES ARE POSSIBLE IN THOSE AREAS AS WELL. SIGNIFICANT RAINFALL /GREATER THAN A QUARTER OF AN INCH/ HAS NOT OCCURRED IN WELL OVER A WEEK ACROSS THE REGION AND STATE OFFICIALS HAVE NOTED THAT FOREST FUELS ARE RATHER DRY AT THIS TIME. RH VALUES ARE EXPECTED TO FALL TO 25 TO 30 PERCENT THIS AFTERNOON...AND S-SW WINDS OF 10 TO 15 MPH WITH SOME HIGHER GUSTS ARE EXPECTED...ALONG WITH AFTERNOON TEMPERATURES IN THE MID 70S TO MID 80S. AS A RESULT...ANY FIRES MAY BECOME DIFFICULT TO CONTROL THIS AFTERNOON INTO THIS EVENING. SPC HAS PLACED MUCH OF THE NORTHEAST IN AN ELEVATED FIRE WEATHER RISK AREA. RH VALUES ARE EXPECTED TO RECOVER TO 90 TO 100 PERCENT TONIGHT WITH SOME RAIN SHOWERS POSSIBLE. RAIN SHOWERS ARE EXPECTED TO BE LIGHT...AND MOST AREAS WON/T SEE A QUARTER OF AN INCH OF RAINFALL. WEST WINDS WILL BE AT 5 T0 15 MPH. WITH RAIN SHOWERS ENDING...AND SKIES STARTING TO CLEAR OUT...RH VALUES ON TUESDAY WILL FALL TO 30 TO 50 PERCENT...WITH THE LOWEST VALUES OVER THE ADIRONDACKS AND SRN VT. HOWEVER...WINDS WILL BE LIGHTER ON TUESDAY...WITH NW WINDS OF 5 TO 10 MPH. DRY WEATHER IS EXPECTED THROUGH THE REMAINDER OF THE WEEK...WITH RH VALUES DROPPING TO NEAR 30 PERCENT EACH AFTERNOON. HOWEVER...WINDS ARE EXPECTED TO BE FAIRLY LIGHT FOR THE REST OF THE WEEK. && .HYDROLOGY... NO HYDROLOGIC ISSUES ARE ANTICIPATED OVER THE NEXT FIVE DAYS. DRY WEATHER WILL BE IN PLACE TODAY WITH ABOVE NORMAL TEMPERATURES. A COLD FRONT WILL BRING SOME LIGHT RAIN SHOWERS TO THE REGION TONIGHT INTO TOMORROW. THE BEST CHANCE WILL BE FOR AREAS NORTH AND WEST OF THE CAPITAL REGION. BASIN AVERAGE RAINFALL WILL GENERALLY ONLY BE A TENTH OR TWO TENTH OF AN INCH. WITH VEGETATION STARTING TO GREEN UP OVER THE AREA...THIS RAINFALL WILL HAVE LITTLE TO NO IMPACT ON AREA RIVERS AND STREAMS. DRY WEATHER WILL BE IN PLACE FOR TUESDAY NIGHT THROUGH THE REMAINDER OF THE WEEK. AS A RESULT...RIVERS AND STREAMS WILL EITHER HOLD STEADY OR SLOWLY RECEDE THROUGH THE WEEK. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEB SITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR NYZ032-033- 038>043-047>054-058>061-063>066-082>084. MA...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR MAZ001-025. VT...NONE. && $$ SYNOPSIS...SND/FRUGIS NEAR TERM...SND SHORT TERM...FRUGIS LONG TERM...IAA AVIATION...IAA FIRE WEATHER...FRUGIS HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1045 AM CDT MON MAY 4 2015 .UPDATE... ISSUED AT 1045 AM CDT MON MAY 4 2015 15Z/10AM SURFACE ANALYSIS SHOWS STATIONARY FRONTAL BOUNDARY EXTENDING FROM SOUTHERN LAKE MICHIGAN TO KANSAS. WIDELY SCATTERED SHOWERS ARE CURRENTLY ONGOING NEAR AND JUST SOUTH OF THE FRONT ACROSS MUCH CENTRAL ILLINOIS...ALTHOUGH AREAL COVERAGE OF PRECIP HAS BEEN DIMINISHING OVER THE PAST COUPLE OF HOURS. 12Z NAM SUGGESTS THE GREATEST INSTABILITY AND STRONGEST LOW-LEVEL WIND SHEAR WILL OVERLAP NEAR AN AREA OF LOW PRESSURE ALONG THE BOUNDARY FROM SOUTHERN IOWA SOUTHWESTWARD INTO KANSAS LATER THIS AFTERNOON. THINK THIS WILL BE THE PRIMARY AREA WHERE WIDESPREAD CONVECTION WILL DEVELOP...WITH ONLY SCATTERED SHOWERS/STORMS FURTHER EAST ACROSS ILLINOIS WHERE INSTABILITY/SHEAR WILL BE WEAKER. HRRR SHOWS THIS TREND AS WELL...WITH CONVECTION DEVELOPING/SPREADING EASTWARD ACROSS THE NORTHERN HALF OF THE KILX CWA AFTER SUNSET. HAVE MADE SOME MINOR ADJUSTMENTS TO THE FORECAST...MAINLY TO FEATURE SCATTERED POPS ALONG/NORTH OF I-72 TODAY AND ONLY ISOLATED FURTHER SOUTH. BETTER RAIN CHANCES WILL ARRIVE TONIGHT. WITH SOME PARTIAL SUNSHINE...AFTERNOON HIGH TEMPERATURES WILL RISE INTO THE UPPER 70S AND LOWER 80S. && .SHORT TERM...(TODAY) ISSUED AT 342 AM CDT MON MAY 4 2015 OUTFLOW BOUNDARY FROM CONVECTION THAT DEVELOPED AHEAD OF A FRONTAL BOUNDARY EXTENDING THROUGH THE GREAT LAKES AND INTO THE CENTRAL PLAINS HAS MOVED INTO PORTIONS OF THE CENTRAL IL FORECAST AREA...EXTENDING FROM NEAR PEORIA TO PONTIAC. BOUNDARY CONTINUES TO TRIGGER SCATTERED THUNDERSTORMS BEHIND IT...WHILE AHEAD LIGHT SHOWERS ARE WIDELY SCATTERED ACROSS CENTRAL IL. MID-LEVEL INSTABILITY ACROSS THE REGION WILL CAUSE SHOWERS AND THUNDERSTORMS TO CONTINUE TO DEVELOP ACROSS MUCH OF CENTRAL IL MAINLY FROM I-70 NORTHWARD THROUGH MORNING. A POSSIBLE LULL IN PRECIPITATION INDICATED BY MODEL FORECASTS LATE MORNING AS CURRENT AREA OF CONVECTION SHIFTS NORTHEASTWARD AND RE-DEVELOPMENT OF CONVECTION TAKES PLACE ALONG THE APPROACHING FRONTAL BOUNDARY FOR THE AFTERNOON. SPC CONTINUES TO ADVERTISE A MARGINAL RISK FOR SEVERE STORMS CONTAINING HAIL/STRONG WIND GUSTS THIS AFTERNOON/EVENING THROUGH MUCH OF CENTRAL AND NORTHERN IL NEAR THE FRONTAL BOUNDARY WHERE AT LEAST SOME OVERLAP OF MODERATE BULK SHEAR MAY COMBINE WITH 1000-2000 J CAPE. HIGH TEMPERATURES QUITE WARM AGAIN TODAY...UPPER 70S TO LOW 80S...WITH BREEZY SW WINDS 10-15 MPH. .LONG TERM...(TONIGHT THROUGH SUNDAY) ISSUED AT 342 AM CDT MON MAY 4 2015 SOME CONVECTION SETTLING INTO THE MIDWEST THIS MORNING ALONG AND AHEAD OF THE BOUNDARY JUST TO THE NORTHWEST. SAME BOUNDARY PROVIDING THE FOCUS FOR SHOWERS TODAY WILL KEEP THE THREAT FOR SOME SHOWERS AND THUNDERSTORMS THROUGH THE OVERNIGHT IN THE NORTHERN HALF OF THE STATE. EXACT LOCATION OF THE STALLED BOUNDARY VARIES A BIT FROM MODEL TO MODEL. SMALL WAVES MOVING ALONG THE BOUNDARY WILL KEEP PRECIP CHANCES IN THE NORTHERN TIER OF THE STATE THROUGH TUESDAY. HIGH PRESSURE SLOWLY BUILDING IN WITH SOME SOUTHERLY WINDS PUSHING THE FRONT BACK TO THE NORTH AND OUT OF THE FORECAST AREA FOR TUESDAY NIGHT THROUGH WED NIGHT. PRECIP CHANCES SLOWLY EDGING BACK INTO CENTRAL ILLINOIS AS AN UPPER LEVEL WAVE PUSHES OUT OF THE SW. THE ENERGY IS PART OF A GENERAL PATTERN SHIFT TO MORE SOUTHWESTERLY FLOW WITH THE UPPER LEVEL TROF DIGGING BACK IN OVER THE SWRN CONUS. THE SFC LOW WITH THAT STORM MOVES OUT INTO THE UPPER MIDWEST AND INTO CANADA BY THE END OF THE WEEK, BUT IN SHIFTING TO MORE SOUTHWESTERLY FLOW ALOFT, OPENS THE DOOR TO A SERIES OF SHORTWAVES THAT KEEP THE FORECAST WET FOR THE END OF THE WORK WEEK AND INTO THE WEEKEND. TEMPS RATHER WARM THROUGH THE FORECAST WITH OVERCAST AND RAINY SKIES KEEPING THE OVERNIGHT LOWS UP A BIT, BUT LIKELY NOT NEARLY AS WARM AS THE TREND IN THE GUIDANCE. HAVE KNOCKED THEM DOWN A COUPLE DEGREES. SOUTHERLY FLOW AND A RELATIVELY WARM AIRMASS KEEPING THE HIGHS A BIT ABOVE NORMS. HOWEVER, WITH THE LIFTING OF THE DEEP TROF OVER THE SW INTO THE GREAT LAKES, THE WARMER AIRMASS IS SHUNTED OFF TO THE EAST AND COOLER AIR MOVES INTO THE MIDWEST AT LEAST BRIEFLY AT THE END OF THE FORECAST PD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 0657 AM CDT MON MAY 4 2015 SCATTERED SHRA/TSRA FROM KSPI-KDEC-KCMI NORTHWARD WITH ISOLD-SCT SHRA TO THE SOUTH AS A COLD FRONTAL BOUNDARY APPROACHES FROM THE NORTHWEST. GENERALLY VFR CONDITIONS WITH CIGS BKN050-070 BUT ISOLD IFR/MVFR VSBYS AND MVFR CIGS IN HEAVIER TSRA AND BR. EXPECT THIS ACTIVITY TO SHIFT SOUTHWARD THROUGH THE DAY AND EVENING BEFORE BEGINNING TO SHIFT BACK NORTHWARD AFTER 06Z. POTENTIAL IMPROVEMENT IN CONDITIONS BRIEFLY FROM AROUND 15-18Z HOWEVER TIMING/OCCURRENCE TOO UNCERTAIN FOR MENTION IN 12Z TAFS. WINDS GENERALLY SSW 8-12 KTS UNTIL 00Z...SHIFTING TO SE04-08 KTS. BRIEFELY GUSTY AND VARIABLE IN VICINITY OF THUNDERSTORMS. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARNES SHORT TERM...ONTON LONG TERM...HJS AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1059 AM CDT MON MAY 4 2015 .DISCUSSION... TEMPERATURES ARE CLIMBING NICELY UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES THIS MORNING...ALREADY IN THE MID 70S TO NEAR 80 DEGREES IN SOME LOCATIONS AS OF 16Z. CURRENT FORECAST SEEMS TO HAVE A GOOD HANDLE ON AFTERNOON HIGHS AND HAVE ONLY MADE MINOR CHANGES TO WIND AND DEW POINT GRIDS TO BETTER MIMIC CURRENT OBSERVATIONS AND TRENDS GOING FORWARD. NO OTHER ADJUSTMENTS ARE NEEDED AT THIS TIME. UPDATED PRODUCTS HAVE ALREADY BEEN SENT. /19/ && .PREV DISCUSSION... /ISSUED 546 AM CDT MON MAY 4 2015/ AVIATION... VFR CONDITIONS TO PREVAIL TODAY. CURRENT IR IMAGERY SHOWING THE INTRUSION OF SOME HIGH/THIN CIRRUS FROM DEBRIS EARLIER IN THE PLAINS. ALSO EVIDENT ACROSS PORTIONS OF NE TX AND SW AR/N LA TERMINALS IS SOME CLOUD COVER IN THE 6-8KFT LEVEL. LOW LEVEL MOISTURE WILL AGAIN BE ON THE INCREASE TODAY WITH SCT CU FIELD EXPECTED TO DEVELOP IN THE 16-18Z TIMEFRAME AND ADVANCE NORTHWARD. A FEW CEILINGS WILL BE POSSIBLE AT THESE HEIGHTS THROUGHOUT THE DAY BUT SCT DECKS BEST DESCRIBE WHAT WILL MOSTLY OCCUR. CANNOT RULE OUT SOME VERY ISOLATED SHOWER ACTIVITY NEAR OUR NE TX TERMINALS TODAY AS THE HRRR IS SHOWING THIS POSSIBILITY. COVERAGE CERTAINLY WILL NOT SUPPORT THE MENTION OF THIS IN OUR 12Z TAF PACKAGE. LOOK FOR WINDS FROM THE SE IN THE 6-12KT RANGE TODAY WITH A FEW HIGHER GUSTS POSSIBLE ACROSS MAINLY OUR NE TX TERMINAL LOCATIONS. SOME INDICATIONS OF POSSIBLE MVFR CEILINGS INCREASING FROM THE SOUTH AFTER MIDNIGHT TONIGHT ACROSS OUR NE TX TERMINAL LOCATIONS. FOR NOW HAVE JUST MADE MENTION OF THIS AT THE LFK TERMINAL. 13 PREV DISCUSSION... /ISSUED 321 AM CDT MON MAY 4 2015/ DISCUSSION... UPPER RIDGING HOLDING IN PLACE ACROSS AREA...WITH SFC HIGH BEGINNING TO DRIFT EAST OF MS RIVER VALLEY. LOW LVL SE-S FLOW TO INCREASE GRADUALLY NEXT COUPLE OF DAYS...AND WILL BEGIN TO INTRODUCE LOW CHANCES FOR CONVECTION FROM THE WEST...BEGINNING TUESDAY. NAM MODEL TOO AGGRESSIVE WITH DEEP MOISTURE...AS EAST TO WEST FRONTAL BOUNDARY WILL REMAIN OVER CENTRAL PLAINS...AND DEVELOPING DRY LINE REMAINING OVER FAR WEST TX THRU THE WEEK. ALTHOUGH DECENT LOW LVL DIRECTIONAL SHEAR WILL SET UP...WILL LACK SPEED IN LOW LVL JET AND NOT EXPECTING MUCH IN SVR WX WITH THE MOSTLY DIURNAL CONVECTION THAT MAY OCCUR. AFTN HIGHS IN LOWER TO MID 80S WILL LIKELY PERSIST...YET OVERNIGHT LOWS MAY EDGE INTO MID TO UPPER 60S AS MOISTURE GRADUALLY DEEPENS. SFC LOW TO DEVELOP OVER PANHANDLES BY WEEKEND...AND AS THIS LOW BEGINS TO KICK OUT TO NE LATE IN WEEKEND...FRONTAL BOUNDARY WILL APPROACH REGION. IN THE MEANTIME...A VERY WEAK SEA BREEZE FRONT MAY BRING ISOLD SHOWERS INTO SE CORNER OF CWA THIS AFTN. VII && .PRELIMINARY POINT TEMPS/POPS... SHV 85 63 83 64 / 10 10 20 20 MLU 84 61 85 61 / 10 10 10 10 DEQ 83 60 82 62 / 10 10 20 20 TXK 84 62 82 63 / 10 10 20 20 ELD 84 60 86 62 / 10 10 10 10 TYR 84 62 80 65 / 10 10 30 30 GGG 84 62 81 65 / 10 10 30 30 LFK 85 65 81 66 / 10 10 30 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 19
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
546 AM CDT MON MAY 4 2015 .AVIATION... VFR CONDITIONS TO PREVAIL TODAY. CURRENT IR IMAGERY SHOWING THE INTRUSION OF SOME HIGH/THIN CIRRUS FROM DEBRIS EARLIER IN THE PLAINS. ALSO EVIDENT ACROSS PORTIONS OF NE TX AND SW AR/N LA TERMINALS IS SOME CLOUD COVER IN THE 6-8KFT LEVEL. LOW LEVEL MOISTURE WILL AGAIN BE ON THE INCREASE TODAY WITH SCT CU FIELD EXPECTED TO DEVELOP IN THE 16-18Z TIMEFRAME AND ADVANCE NORTHWARD. A FEW CEILINGS WILL BE POSSIBLE AT THESE HEIGHTS THROUGHOUT THE DAY BUT SCT DECKS BEST DESCRIBE WHAT WILL MOSTLY OCCUR. CANNOT RULE OUT SOME VERY ISOLATED SHOWER ACTIVITY NEAR OUR NE TX TERMINALS TODAY AS THE HRRR IS SHOWING THIS POSSIBILITY. COVERAGE CERTAINLY WILL NOT SUPPORT THE MENTION OF THIS IN OUR 12Z TAF PACKAGE. LOOK FOR WINDS FROM THE SE IN THE 6-12KT RANGE TODAY WITH A FEW HIGHER GUSTS POSSIBLE ACROSS MAINLY OUR NE TX TERMINAL LOCATIONS. SOME INDICATIONS OF POSSIBLE MVFR CEILINGS INCREASING FROM THE SOUTH AFTER MIDNIGHT TONIGHT ACROSS OUR NE TX TERMINAL LOCATIONS. FOR NOW HAVE JUST MADE MENTION OF THIS AT THE LFK TERMINAL. 13 && .PREV DISCUSSION... /ISSUED 321 AM CDT MON MAY 4 2015/ DISCUSSION... UPPER RIDGING HOLDING IN PLACE ACROSS AREA...WITH SFC HIGH BEGINNING TO DRIFT EAST OF MS RIVER VALLEY. LOW LVL SE-S FLOW TO INCREASE GRADUALLY NEXT COUPLE OF DAYS...AND WILL BEGIN TO INTRODUCE LOW CHANCES FOR CONVECTION FROM THE WEST...BEGINNING TUESDAY. NAM MODEL TOO AGGRESSIVE WITH DEEP MOISTURE...AS EAST TO WEST FRONTAL BOUNDARY WILL REMAIN OVER CENTRAL PLAINS...AND DEVELOPING DRY LINE REMAINING OVER FAR WEST TX THRU THE WEEK. ALTHOUGH DECENT LOW LVL DIRECTIONAL SHEAR WILL SET UP...WILL LACK SPEED IN LOW LVL JET AND NOT EXPECTING MUCH IN SVR WX WITH THE MOSTLY DIURNAL CONVECTION THAT MAY OCCUR. AFTN HIGHS IN LOWER TO MID 80S WILL LIKELY PERSIST...YET OVERNIGHT LOWS MAY EDGE INTO MID TO UPPER 60S AS MOISTURE GRADUALLY DEEPENS. SFC LOW TO DEVELOP OVER PANHANDLES BY WEEKEND...AND AS THIS LOW BEGINS TO KICK OUT TO NE LATE IN WEEKEND...FRONTAL BOUNDARY WILL APPROACH REGION. IN THE MEANTIME...A VERY WEAK SEA BREEZE FRONT MAY BRING ISOLD SHOWERS INTO SE CORNER OF CWA THIS AFTN. VII && .PRELIMINARY POINT TEMPS/POPS... SHV 85 63 83 64 / 10 10 20 20 MLU 84 61 85 61 / 10 10 10 10 DEQ 83 60 82 62 / 10 10 20 20 TXK 84 62 82 63 / 10 10 20 20 ELD 84 60 86 62 / 10 10 10 10 TYR 84 62 80 65 / 10 10 30 30 GGG 84 62 81 65 / 10 10 30 30 LFK 85 65 81 66 / 10 10 30 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ VII/13
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1200 PM EDT MON MAY 4 2015 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 1117 AM EDT MON MAY 4 2015 FAIR WEATHER IS EXPECTED INTO TONIGHT THEN SOME SHOWERS AND THUNDERSTORMS WILL RETURN LATE TONIGHT INTO TUESDAY AS LOW PRESSURE TRACKS ALONG A FRONT STALLED JUST SOUTH OF LOWER MICHIGAN. MOSTLY FAIR AND WARM WEATHER IS EXPECTED FOR WEDNESDAY AND THURSDAY WITH SHOWERS AND THUNDERSTORMS OVER THE WEEKEND AS ANOTHER LOW MOVES THROUGH. && .UPDATE... ISSUED AT 1117 AM EDT MON MAY 4 2015 DROPPED POPS FOR TODAY AND THIS EVENING AS THE FRONT IS THROUGH AND RADAR TRENDS ALONG WITH THE HRRR SHOWS THE RAIN STAYING SOUTH OF THE FORECAST AREA INTO THIS EVENING. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 314 AM EDT MON MAY 4 2015 FORECAST CONCERNS DEAL WITH THE EVOLUTION OF THE FRONTAL BOUNDARY THAT WILL BE MOVING THROUGH THE CWA TODAY. THE FORECAST HASN`T CHANGED MUCH AND SHOWERS AND STORMS ARE EXPECTED THROUGH WEDNESDAY. RADAR SHOWS SHOWERS AND EMBEDDED STORMS MOVING ACROSS THE CWA ATTM. THIS ACTIVITY IS AHEAD OF THE COLD FRONT WHICH IS STILL OVER WISCONSIN. THE ECHO PATTERN APPEARS AS A PSEUDO WARM FRONT AIDED BY THE LLJ AIMED AT SW LWR MI. CLOUD TOPS ARE WARMING OVER WISCONSIN AND WE SHOULD SEE A GENERAL DECREASE IN ECHO INTENSITY TOWARD MORNING WHEN THE COLD FRONT APPROACHES. HIGHEST POPS THIS AFTERNOON WILL BE OVER THE SOUTHERN CWA AS THE FRONT MOVES OVER NORTHERN INDIANA. WE/LL KEEP SHOWERS/STORMS IN THE GRIDS TONIGHT AS THE ECMWF SHOWS A WAVE DEVELOPING ON THE BOUNDARY OVER SOUTHERN IOWA AND MOVING EAST. THE GFS/NAM DON/T REALLY SHOW THE WAVE BUT DO SHOW SOME PCPN NEAR THE BOUNDARY TUESDAY. THIS BOUNDARY WILL LIFT NORTH IN RESPONSE TO A DEEPENING PLAINS LOW. TUESDAY WILL BE THE COOLEST DAY OF THE SHORT TERM WITH HIGHS IN THE 60S. AFTER THE FRONTAL BOUNDARY MOVES NORTH...TEMPERATURES WILL CLIMB INTO THE 70S WEDNESDAY. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 314 AM EDT MON MAY 4 2015 EXPECT ABOVE NORMAL TEMPERATURES THROUGH THE LONG TERM PERIOD. WHILE THERE IS SOME THREAT FOR THUNDERSTORMS EACH DAY THE CHANCES SEEM HIGHEST SATURDAY THROUGH MONDAY. THERE IS SOME POTENTIAL FOR STRONG STORMS LATE IN THE WEEKEND INTO EARLY NEXT WEEK. A CLOSED UPPER LOW OFF THE COAST OF THE STATE OF WASHINGTON AND SOUTHERN BRITISH COLUMBIA EARLY THIS MORNING DIGS SOUTHEAST INTO THE SOUTHWESTERN CONUS BY LATE THIS WEEK. THIS BUILDS AN UPPER LEVEL RIDGE OVER THE EASTERN CONUS THURSDAY INTO FRIDAY. THAT SHOULD FOR THE MOST PART KEEP THE THREAT OF SHOWERS DOWN AND INCREASE THE CHANCE FOR HIGHS IN THE LOWER TO MID 80S. THERE IS A SHORTWAVE THAT TRIES TO COME OUT OF THE WESTERN SYSTEM THURSDAY BUT THE ENERGY FOR THAT SHOULD MOSTLY BE WEST OF MICHIGAN. DURING THE WEEKEND A MUCH MORE POWERFUL PACIFIC SYSTEM BOOTS THE SYSTEM OVER THE SOUTHWEST INTO THE CENTRAL CONUS BY SUNDAY. IT IS IN THE SUNDAY TO MONDAY TIME FRAME OUR RISK FOR STRONGER STORMS AND HEAVY RAIN WOULD BE GREATEST. MODEL AGREEMENT ON THIS IS REASONABLE BUT GIVEN HOW FAR OUT IN TIME THIS IS... DEALS WILL SURELY CHANGE AS WE GET CLOSER TO NEXT WEEKEND. MY BOTTOM LINE IS WARM AND MOSTLY DRY THURSDAY AND FRIDAY...SHOWERS AND THUNDERSTORMS SATURDAY INTO MONDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY) ISSUED AT 1200 PM EDT MON MAY 4 2015 VFR CONDITIONS WILL CONTINUE AT ALL THE TERMINALS THIS AFTERNOON AND EVENING. CONDITIONS WILL GRADUALLY DETERIORATE TO MAINLY MVFR DURING THE EARLY TO MID MORNING HOURS TUESDAY AS LOW CLOUDS MOVE IN ALONG WITH SOME SHOWERS AT OUR SOUTHERNMOST TERMINALS. SOME PATCHY FOG IS ANTICIPATED DURING THE EARLY TO MID MORNING HOURS TUESDAY AS WELL. THERE IS NOT ENOUGH POTENTIAL FOR THUNDERSTORMS TO WARRANT INCLUSION IN ANY OF THE TERMINAL FORECASTS AT THIS TIME. THE THREAT FOR THUNDERSTORMS SHOULD STAY SOUTH OF ALL THE TERMINALS THROUGH 18Z TUESDAY DUE MAINLY TO THE LACK OF SURFACE OR ELEVATED INSTABILITY. && .MARINE... ISSUED AT 314 AM EDT MON MAY 4 2015 SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH WEDNESDAY. OUTSIDE OF THUNDERSTORMS WINDS AND WAVES WILL BE BELOW SMALL CRAFT ADVISORY CRITERIA. && .HYDROLOGY... ISSUED AT 1137 AM EDT MON MAY 4 2015 THE FOCUS WILL BE ON THE ADDITIONAL BOUTS OF RAINFALL POSSIBLE IN THE WEEK AHEAD. WHILE THE PATTERN STILL LOOKS ACTIVE IT IS NOT PROMISING THAT WE WILL SEE ANY WIDESPREAD HEAVY RAIN. BENEFICIAL AMOUNTS SHOULD AVERAGE OUT TO A QUARTER INCH OR SO WITH EACH EPISODE THROUGH THE WORK WEEK. THAT MAY LEAD TO DECENT TOTALS IN THE GRAND SCHEME BUT NOTHING THAT PUTS RIVERS OVER THEIR BANKS. THE NEXT CHANCE OF RAIN COMES WHEN THE STALLING FRONT TO OUR SOUTH RETURNS AS A WARM FRONT TUESDAY AND INTO EARLY WEDNESDAY. EVEN THIS LOOKS TO COME IN A PIECE-WISE FASHION...ONCE LATE TONIGHT AND AGAIN LATE TUESDAY INTO EARLY WEDNESDAY. THE BEST CHANCE AT RAIN THEN ENTERS THE PICTURE LATE IN THE WEEK AND INTO NEXT WEEKEND WITH AN APPROACHING SYSTEM. THIS IS WHEN WE COULD PICK UP OUR HIGHEST TOTALS...PENDING THE NORTHERN EXTENT OF THE WARM FRONT OUT AHEAD OF THE SYSTEM. SEVEN DAY TOTALS ON THE ORDER OF AN INCH TO AROUND AN INCH AND A HALF KEEP CONCERNS LOW AS IT IS RECIEVED IN CHUNKS WITH SEVERAL HOURS OF DRY TIME BETWEEN. LOCALIZED HEAVIER RAINFALL CANNOT BE RULED OUT...BUT DURATION AND COVERAGE IS NOT LOOKING EXTENSIVE AT THIS POINT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...OSTUNO SYNOPSIS...OSTUNO SHORT TERM...04 LONG TERM...WDM AVIATION...LAURENS HYDROLOGY...JAM MARINE...04
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1137 AM EDT MON MAY 4 2015 LATEST UPDATE... HYDRO .SYNOPSIS... ISSUED AT 1117 AM EDT MON MAY 4 2015 FAIR WEATHER IS EXPECTED INTO TONIGHT THEN SOME SHOWERS AND THUNDERSTORMS WILL RETURN LATE TONIGHT INTO TUESDAY AS LOW PRESSURE TRACKS ALONG A FRONT STALLED JUST SOUTH OF LOWER MICHIGAN. MOSTLY FAIR AND WARM WEATHER IS EXPECTED FOR WEDNESDAY AND THURSDAY WITH SHOWERS AND THUNDERSTORMS OVER THE WEEKEND AS ANOTHER LOW MOVES THROUGH. && .UPDATE... ISSUED AT 1117 AM EDT MON MAY 4 2015 DROPPED POPS FOR TODAY AND THIS EVENING AS THE FRONT IS THROUGH AND RADAR TRENDS ALONG WITH THE HRRR SHOWS THE RAIN STAYING SOUTH OF THE FORECAST AREA INTO THIS EVENING. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 314 AM EDT MON MAY 4 2015 FORECAST CONCERNS DEAL WITH THE EVOLUTION OF THE FRONTAL BOUNDARY THAT WILL BE MOVING THROUGH THE CWA TODAY. THE FORECAST HASN`T CHANGED MUCH AND SHOWERS AND STORMS ARE EXPECTED THROUGH WEDNESDAY. RADAR SHOWS SHOWERS AND EMBEDDED STORMS MOVING ACROSS THE CWA ATTM. THIS ACTIVITY IS AHEAD OF THE COLD FRONT WHICH IS STILL OVER WISCONSIN. THE ECHO PATTERN APPEARS AS A PSEUDO WARM FRONT AIDED BY THE LLJ AIMED AT SW LWR MI. CLOUD TOPS ARE WARMING OVER WISCONSIN AND WE SHOULD SEE A GENERAL DECREASE IN ECHO INTENSITY TOWARD MORNING WHEN THE COLD FRONT APPROACHES. HIGHEST POPS THIS AFTERNOON WILL BE OVER THE SOUTHERN CWA AS THE FRONT MOVES OVER NORTHERN INDIANA. WE/LL KEEP SHOWERS/STORMS IN THE GRIDS TONIGHT AS THE ECMWF SHOWS A WAVE DEVELOPING ON THE BOUNDARY OVER SOUTHERN IOWA AND MOVING EAST. THE GFS/NAM DON/T REALLY SHOW THE WAVE BUT DO SHOW SOME PCPN NEAR THE BOUNDARY TUESDAY. THIS BOUNDARY WILL LIFT NORTH IN RESPONSE TO A DEEPENING PLAINS LOW. TUESDAY WILL BE THE COOLEST DAY OF THE SHORT TERM WITH HIGHS IN THE 60S. AFTER THE FRONTAL BOUNDARY MOVES NORTH...TEMPERATURES WILL CLIMB INTO THE 70S WEDNESDAY. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 314 AM EDT MON MAY 4 2015 EXPECT ABOVE NORMAL TEMPERATURES THROUGH THE LONG TERM PERIOD. WHILE THERE IS SOME THREAT FOR THUNDERSTORMS EACH DAY THE CHANCES SEEM HIGHEST SATURDAY THROUGH MONDAY. THERE IS SOME POTENTIAL FOR STRONG STORMS LATE IN THE WEEKEND INTO EARLY NEXT WEEK. A CLOSED UPPER LOW OFF THE COAST OF THE STATE OF WASHINGTON AND SOUTHERN BRITISH COLUMBIA EARLY THIS MORNING DIGS SOUTHEAST INTO THE SOUTHWESTERN CONUS BY LATE THIS WEEK. THIS BUILDS AN UPPER LEVEL RIDGE OVER THE EASTERN CONUS THURSDAY INTO FRIDAY. THAT SHOULD FOR THE MOST PART KEEP THE THREAT OF SHOWERS DOWN AND INCREASE THE CHANCE FOR HIGHS IN THE LOWER TO MID 80S. THERE IS A SHORTWAVE THAT TRIES TO COME OUT OF THE WESTERN SYSTEM THURSDAY BUT THE ENERGY FOR THAT SHOULD MOSTLY BE WEST OF MICHIGAN. DURING THE WEEKEND A MUCH MORE POWERFUL PACIFIC SYSTEM BOOTS THE SYSTEM OVER THE SOUTHWEST INTO THE CENTRAL CONUS BY SUNDAY. IT IS IN THE SUNDAY TO MONDAY TIME FRAME OUR RISK FOR STRONGER STORMS AND HEAVY RAIN WOULD BE GREATEST. MODEL AGREEMENT ON THIS IS REASONABLE BUT GIVEN HOW FAR OUT IN TIME THIS IS... DEALS WILL SURELY CHANGE AS WE GET CLOSER TO NEXT WEEKEND. MY BOTTOM LINE IS WARM AND MOSTLY DRY THURSDAY AND FRIDAY...SHOWERS AND THUNDERSTORMS SATURDAY INTO MONDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 626 AM EDT MON MAY 4 2015 ONCE THIS AREA OF CONVECTION AHEAD OF THE COLD FRONT CLEARS THE AREA BY 12Z OVER THE WESTERN SECTIONS AND 15Z OVER THE EASTERN SECTIONS THE AREA OF MVFR CIGS CURRENTLY OVER WISCONSIN WILL FOLLOW FOR TH 13Z TO 16Z TIME FRAME. THAT WILL MOVE OUT OF THE AREA BY 16Z TO 18Z LEAVING MOSTLY SUNNY SKIES AND A NORTHWEST WIND AROUND 10 KNOTS FOR THE REMAINDER OF THE DAY. THIS EVENING SHOULD SEE VFR CONDITIONS CONTINUE THROUGH AROUND 06Z. THEN A WAVE ON THE FRONT WILL BRING SHOWERS BACK TO THE AREA WITH LOWERING CIG AND VSBY. && .MARINE... ISSUED AT 314 AM EDT MON MAY 4 2015 SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH WEDNESDAY. OUTSIDE OF THUNDERSTORMS WINDS AND WAVES WILL BE BELOW SMALL CRAFT ADVISORY CRITERIA. && .HYDROLOGY... ISSUED AT 1137 AM EDT MON MAY 4 2015 THE FOCUS WILL BE ON THE ADDITIONAL BOUTS OF RAINFALL POSSIBLE IN THE WEEK AHEAD. WHILE THE PATTERN STILL LOOKS ACTIVE IT IS NOT PROMISING THAT WE WILL SEE ANY WIDESPREAD HEAVY RAIN. BENEFICIAL AMOUNTS SHOULD AVERAGE OUT TO A QUARTER INCH OR SO WITH EACH EPISODE THROUGH THE WORK WEEK. THAT MAY LEAD TO DECENT TOTALS IN THE GRAND SCHEME BUT NOTHING THAT PUTS RIVERS OVER THEIR BANKS. THE NEXT CHANCE OF RAIN COMES WHEN THE STALLING FRONT TO OUR SOUTH RETURNS AS A WARM FRONT TUESDAY AND INTO EARLY WEDNESDAY. EVEN THIS LOOKS TO COME IN A PIECE-WISE FASHION...ONCE LATE TONIGHT AND AGAIN LATE TUESDAY INTO EARLY WEDNESDAY. THE BEST CHANCE AT RAIN THEN ENTERS THE PICTURE LATE IN THE WEEK AND INTO NEXT WEEKEND WITH AN APPROACHING SYSTEM. THIS IS WHEN WE COULD PICK UP OUR HIGHEST TOTALS...PENDING THE NORTHERN EXTENT OF THE WARM FRONT OUT AHEAD OF THE SYSTEM. SEVEN DAY TOTALS ON THE ORDER OF AN INCH TO AROUND AN INCH AND A HALF KEEP CONCERNS LOW AS IT IS RECIEVED IN CHUNKS WITH SEVERAL HOURS OF DRY TIME BETWEEN. LOCALIZED HEAVIER RAINFALL CANNOT BE RULED OUT...BUT DURATION AND COVERAGE IS NOT LOOKING EXTENSIVE AT THIS POINT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...OSTUNO SYNOPSIS...OSTUNO SHORT TERM...04 LONG TERM...WDM AVIATION...WDM HYDROLOGY...JAM MARINE...04
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1118 AM EDT MON MAY 4 2015 LATEST UPDATE... UPDATE/SYNOPSIS .SYNOPSIS... ISSUED AT 1117 AM EDT MON MAY 4 2015 FAIR WEATHER IS EXPECTED INTO TONIGHT THEN SOME SHOWERS AND THUNDERSTORMS WILL RETURN LATE TONIGHT INTO TUESDAY AS LOW PRESSURE TRACKS ALONG A FRONT STALLED JUST SOUTH OF LOWER MICHIGAN. MOSTLY FAIR AND WARM WEATHER IS EXPECTED FOR WEDNESDAY AND THURSDAY WITH SHOWERS AND THUNDERSTORMS OVER THE WEEKEND AS ANOTHER LOW MOVES THROUGH. && .UPDATE... ISSUED AT 1117 AM EDT MON MAY 4 2015 DROPPED POPS FOR TODAY AND THIS EVENING AS THE FRONT IS THROUGH AND RADAR TRENDS ALONG WITH THE HRRR SHOWS THE RAIN STAYING SOUTH OF THE FORECAST AREA INTO THIS EVENING. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 314 AM EDT MON MAY 4 2015 FORECAST CONCERNS DEAL WITH THE EVOLUTION OF THE FRONTAL BOUNDARY THAT WILL BE MOVING THROUGH THE CWA TODAY. THE FORECAST HASN`T CHANGED MUCH AND SHOWERS AND STORMS ARE EXPECTED THROUGH WEDNESDAY. RADAR SHOWS SHOWERS AND EMBEDDED STORMS MOVING ACROSS THE CWA ATTM. THIS ACTIVITY IS AHEAD OF THE COLD FRONT WHICH IS STILL OVER WISCONSIN. THE ECHO PATTERN APPEARS AS A PSEUDO WARM FRONT AIDED BY THE LLJ AIMED AT SW LWR MI. CLOUD TOPS ARE WARMING OVER WISCONSIN AND WE SHOULD SEE A GENERAL DECREASE IN ECHO INTENSITY TOWARD MORNING WHEN THE COLD FRONT APPROACHES. HIGHEST POPS THIS AFTERNOON WILL BE OVER THE SOUTHERN CWA AS THE FRONT MOVES OVER NORTHERN INDIANA. WE/LL KEEP SHOWERS/STORMS IN THE GRIDS TONIGHT AS THE ECMWF SHOWS A WAVE DEVELOPING ON THE BOUNDARY OVER SOUTHERN IOWA AND MOVING EAST. THE GFS/NAM DON/T REALLY SHOW THE WAVE BUT DO SHOW SOME PCPN NEAR THE BOUNDARY TUESDAY. THIS BOUNDARY WILL LIFT NORTH IN RESPONSE TO A DEEPENING PLAINS LOW. TUESDAY WILL BE THE COOLEST DAY OF THE SHORT TERM WITH HIGHS IN THE 60S. AFTER THE FRONTAL BOUNDARY MOVES NORTH...TEMPERATURES WILL CLIMB INTO THE 70S WEDNESDAY. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 314 AM EDT MON MAY 4 2015 EXPECT ABOVE NORMAL TEMPERATURES THROUGH THE LONG TERM PERIOD. WHILE THERE IS SOME THREAT FOR THUNDERSTORMS EACH DAY THE CHANCES SEEM HIGHEST SATURDAY THROUGH MONDAY. THERE IS SOME POTENTIAL FOR STRONG STORMS LATE IN THE WEEKEND INTO EARLY NEXT WEEK. A CLOSED UPPER LOW OFF THE COAST OF THE STATE OF WASHINGTON AND SOUTHERN BRITISH COLUMBIA EARLY THIS MORNING DIGS SOUTHEAST INTO THE SOUTHWESTERN CONUS BY LATE THIS WEEK. THIS BUILDS AN UPPER LEVEL RIDGE OVER THE EASTERN CONUS THURSDAY INTO FRIDAY. THAT SHOULD FOR THE MOST PART KEEP THE THREAT OF SHOWERS DOWN AND INCREASE THE CHANCE FOR HIGHS IN THE LOWER TO MID 80S. THERE IS A SHORTWAVE THAT TRIES TO COME OUT OF THE WESTERN SYSTEM THURSDAY BUT THE ENERGY FOR THAT SHOULD MOSTLY BE WEST OF MICHIGAN. DURING THE WEEKEND A MUCH MORE POWERFUL PACIFIC SYSTEM BOOTS THE SYSTEM OVER THE SOUTHWEST INTO THE CENTRAL CONUS BY SUNDAY. IT IS IN THE SUNDAY TO MONDAY TIME FRAME OUR RISK FOR STRONGER STORMS AND HEAVY RAIN WOULD BE GREATEST. MODEL AGREEMENT ON THIS IS REASONABLE BUT GIVEN HOW FAR OUT IN TIME THIS IS... DEALS WILL SURELY CHANGE AS WE GET CLOSER TO NEXT WEEKEND. MY BOTTOM LINE IS WARM AND MOSTLY DRY THURSDAY AND FRIDAY...SHOWERS AND THUNDERSTORMS SATURDAY INTO MONDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 626 AM EDT MON MAY 4 2015 ONCE THIS AREA OF CONVECTION AHEAD OF THE COLD FRONT CLEARS THE AREA BY 12Z OVER THE WESTERN SECTIONS AND 15Z OVER THE EASTERN SECTIONS THE AREA OF MVFR CIGS CURRENTLY OVER WISCONSIN WILL FOLLOW FOR TH 13Z TO 16Z TIME FRAME. THAT WILL MOVE OUT OF THE AREA BY 16Z TO 18Z LEAVING MOSTLY SUNNY SKIES AND A NORTHWEST WIND AROUND 10 KNOTS FOR THE REMAINDER OF THE DAY. THIS EVENING SHOULD SEE VFR CONDITIONS CONTINUE THROUGH AROUND 06Z. THEN A WAVE ON THE FRONT WILL BRING SHOWERS BACK TO THE AREA WITH LOWERING CIG AND VSBY. && .MARINE... ISSUED AT 314 AM EDT MON MAY 4 2015 SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH WEDNESDAY. OUTSIDE OF THUNDERSTORMS WINDS AND WAVES WILL BE BELOW SMALL CRAFT ADVISORY CRITERIA. && .HYDROLOGY... ISSUED AT 1136 AM EDT SUN MAY 3 2015 RIVERS ARE RUNNING WELL WITHIN BANKS AND REMAIN STEADY...IF NOT FALLING EVER-SO-SLIGHTLY. THOUGH FLOODING IS NOT ANTICIPATED AT THIS TIME...THE PATTERN BECOMES ACTIVE OVER THE COURSE OF THE UPCOMING WEEK AND WE MAY SEE WITHIN BANK RISES. PRECIPITATION IS EXPECTED TO DEVELOPED AND PROGRESS FROM NORTH TO SOUTH BEGINNING LATE TONIGHT. THE FRONTAL BOUNDARY RESPONSIBLE FOR THE PRECIPITATION WILL STALL NEAR THE SOUTHERN LOWER MICHIGAN BORDER WHICH WILL LEAD TO SOME OF THE HIGHER TOTALS ALIGNING ALONG AND SOUTH OF I-94. THIS FRONT THEN RETURNS NORTH NEAR MIDWEEK AND PROVIDES ANOTHER DECENT SHOT AT PRECIPITATION FOR CENTRAL LOWER MICHIGAN DURING THAT TIME FRAME. YET ANOTHER ROUND OF WET WEATHER IS POISED TO MOVE THROUGH LATE IN THE WEEK AND INTO NEXT WEEKEND. THE MAIN IMPACTS WOULD LIKELY BE MINOR AND NOT REALLY FELT UNTIL WE GET INTO THE NEW WORK WEEK. LOCATIONS THAT ARE ALREADY RAIN SOAKED AND RECEIVE ANY ADDITIONAL CONVECTIVE PRECIPITATION COULD SEE MINOR PONDING ON ROADWAYS...OR LOW LYING AREAS THAT ARE TYPICALLY AFFECTED BY HEAVIER RAIN. AN ADDITIONAL NOTE IS THAT WE ARE DRY NOW AND GREEN-UP IS OCCURRING IN MANY LOCATIONS. THIS WILL DEFINITELY HELP IN TAKING UP A LOT OF THE MOISTURE THAT FALLS. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...OSTUNO SYNOPSIS...OSTUNO SHORT TERM...04 LONG TERM...WDM AVIATION...WDM HYDROLOGY...JAM MARINE...04
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1027 AM EDT MON MAY 4 2015 .UPDATE... MOISTURE AXIS (850-700 MB THETA-E RIDGE) WORKING THROUGH SOUTHEAST MICHIGAN THIS MORNING...GENERATING LINE OF SHOWERS/EMBEDDED THUNDER. AMOUNT OF RECOVERY BEHIND THIS BATCH OF SHOWERS WILL BE KEY THIS AFTERNOON...AS SURFACE COLD FRONT ADVANCES SOUTH THROUGH THE CWA. STILL...SURFACE DEW PTS WILL LIKELY BE HARD PRESSED TO REACH/EXCEED 60 DEGREES...AND CAPES WILL LIKELY BUILD TO AROUND 1000 J/KG WITH TEMPS IN THE 70S. PLANNING ON CARRYING SCATTERED/CHANCE POPS FOR THE AFTERNOON HOURS WITH THE LACK OF UPPER LEVEL SUPPORT...AS HRRR ALSO SHOWING LITTLE ACTIVITY. COULD SEE A SCENARIO WHERE COOLER WATERS OF LAKE HURON PROVIDE LITTLE BOOST TO THE COLD FRONT MOVING THROUGH THE THUMB REGION...AND WOULD NOT RULE OUT THE ENHANCED CONVERGENCE ALLOWING AN ISOLATED CELL TO APPROACH SEVERE LIMITS...AS FREEZING LEVELS ARE IDEAL...AND WIND FIELDS ARE MODERATE (25 TO 30 KNOTS OF 0-5KM BULK SHEAR). BUT AGAIN...THAT IS ASSUMING WE SUFFICIENTALY RECOVER...IF CLOUDS REMAIN LOCKED IN...THEN FORGET IT. && .AVIATION...ISSUED 708 AM EDT MON MAY 4 2015 A WEAKENING PATTERN OF SHOWERS WILL MOVE THE REST OF THE WAY THROUGH SE MICHIGAN DURING THE MORNING AS MOISTURE BUILDS AHEAD OF THE COLD FRONT. THE FRONT IS ON A SLIGHTLY SLOWER SCHEDULE TO MOVE THROUGH THE REGION DURING THE AFTERNOON AND EVENING...AND WILL BECOME THE FOCUS FOR REDEVELOPMENT OF SHOWERS AND POSSIBLY THUNDERSTORMS MAINLY SOUTH OF MBS AND FNT. INTERVALS OF MVFR RESTRICTION ARE LIKELY WITH THE SHOWERS BUT THUNDERSTORM TIMING AND COVERAGE NEEDS FURTHER REFINEMENT BEFORE INCLUSION IN THE FORECAST AT ANY ONE TERMINAL. NORTHWEST LOW LEVEL FLOW POST FRONT WILL VEER TOWARD THE NORTHEAST DURING THE EVENING...AND THEN TOWARD THE EAST OVERNIGHT. VFR IS EXPECTED AS DRY AND COOLER AIR MOVES IN FROM THE NORTH. SHOWERS WILL REMAIN POSSIBLE IN THE DTW AREA AS THE FRONT STALLS NEAR THE OHIO BORDER THROUGH TUESDAY MORNING. FOR DTW...VFR WILL PERSIST THROUGH A WEAKENING PATTERN OF SHOWERS DURING THE MORNING. A BREAK IN THE PRECIPITATION WILL THEN PRECEDE A COLD FRONT THAT IS ON A SLIGHTLY LATER SCHEDULE TO MOVE THROUGH THE DTW AREA DURING LATE AFTERNOON TO EARLY EVENING. THIS WILL PROVIDE A BETTER WINDOW FOR THUNDERSTORM POTENTIAL COMPARED TO POINTS NORTH BUT TIMING AND COVERAGE STILL NEED REFINEMENT BEFORE STORMS ARE ADDED TO THE FORECAST. THE FRONT IS STILL EXPECTED TO STALL NEAR THE OHIO BORDER WHICH WILL KEEP RAIN IN THE FORECAST OVERNIGHT THROUGH TUESDAY MORNING. //DTW THRESHOLD PROBABILITIES... * MEDIUM FOR CEILING AOB 5000FT THIS AFTERNOON AND TONIGHT. * LOW FOR THUNDERSTORMS THIS AFTERNOON AND EVENING. && .PREV DISCUSSION...ISSUED 352 AM EDT MON MAY 4 2015 SHORT TERM... TODAY AND TONIGHT AFTER AN OUTSTANDING WEEKEND OF DRY AND WARM WEATHER...AN ACTIVE PRECIPITATION PATTERN WILL GET UNDERWAY TO START THE WEEK. BEGINNING THIS MORNING...SHOWERS AND A FEW THUNDERSTORMS WILL MARK THE LEADING EDGE OF INCREASED LOW LEVEL MOISTURE ADVANCING THROUGH LOWER MICHIGAN. MORNING COVERAGE WILL BE GREATEST FROM FLINT TO THE TRI CITIES AND NORTHERN THUMB BUT ALL AREAS WILL HAVE AT LEAST A CHANCE OF SHOWERS AS THE MOISTURE SURGE PROGRESSES THROUGH THE REGION. THE COLD FRONT APPROACHING FROM THE WEST WILL THEN TAKE OVER DURING THE AFTERNOON. THAT IS WHEN THE HIGHEST CONCENTRATION OF SHOWERS AND STORMS WILL SHIFT GENERALLY SOUTH OF THE INTERSTATE 69 CORRIDOR THROUGH EARLY EVENING. AFTERNOON THUNDERSTORM POTENTIAL WILL BE STRONGLY DEPENDENT ON RECOVERY OF SURFACE BASED INSTABILITY THAT WILL BE LIMITED BY MORNING CLOUDS AND PRECIPITATION. RADAR OBSERVATIONS INDICATE SHOWERS AND A FEW THUNDERSTORMS EXPANDING IN COVERAGE OVER SW LOWER MICHIGAN SINCE MIDNIGHT. THIS IS OCCURRING ON THE LEADING EDGE OF THE LOW LEVEL MOISTURE AXIS WITH A MODESTLY INCREASING LOW LEVEL JET...BOTH OF WHICH ARE GENERATING A TYPICAL PATTERN OF NOCTURNAL ELEVATED INSTABILITY. THE 00Z MODELS HAVE A REASONABLE HANDLE ON THIS SCENARIO JUDGING BY THETA-E AND WIND FIELDS IN THE 850-700 MB LAYER. PREFER THOSE THAT ARE MORE BULLISH ON THE MAINTENANCE OF MORNING QPF OVER SE MICHIGAN NOW THAT MOISTURE ADVECTION IS PROVING ADEQUATE TO GENERATE CONVECTION. FOR NOW...PLAN TO NUDGE MORNING POPS UP INTO THE CATEGORICAL RANGE IN THE TRI CITIES AND INTO HIGH LIKELY SOUTHWARD ALONG THE U.S. 23 CORRIDOR TO ACCOUNT FOR SOUTHWARD EXPANSION ALONG THE MOISTURE GRADIENT. THERE IS GOOD MODEL AGREEMENT INDICATING THE COLD FRONT IS ON PACE TO BE THROUGH THE TRI CITIES AND NORTHERN THUMB BY EARLY AFTERNOON. EXPECT IT WILL TAKE UNTIL THEN FOR BOUNDARY LAYER TEMPERATURE RECOVERY TO OCCUR ON THE HEELS OF THE MORNING SHOWERS AND CONVECTIVE CLOUD DEBRIS. THIS SUGGESTS LEANING THE FORECAST TOWARD THE LOWER END OF THE MODEL RANGE FOR SURFACE BASED CAPE. THE NAM CONTINUES TO ADVERTISE CAPE REACHING 1500-1800 J/KG SUBJECT TO SURFACE DEWPOINT RISING INTO THE LOWER 60S AS SURFACE TEMPERATURE RECOVERS INTO THE MID TO UPPER 70S. THE RAP AND GFS ALSO INDICATE SURFACE DEWPOINT REACHING THE LOWER 60S BUT PRODUCE CAPE CLOSER TO 1000 J/KG WITH MAIN DIFFERENCE BEING SHALLOWER MID LEVEL LAPSE RATES. THIS IS GENERALLY PREFERRED CONSIDERING THE WARM LARGE SCALE UPPER AIR PATTERN...ESPECIALLY FOR THIS TIME OF YEAR. THE ONE WILD CARD TO MONITOR IS THE HINT OF MCV DEVELOPMENT OVER THE MIDWEST THAT COULD HELP A FEW STORMS OVERACHIEVE. WITH THAT IN MIND...THE SPC OUTLOOK FOR MARGINAL LOOKS REASONABLE BEFORE THE FRONT SETTLES SOUTH OF THE OHIO BORDER BY MIDNIGHT. LONG TERM...TUESDAY THROUGH SUNDAY MID LEVEL WESTERLIES TAKE HOLD TUESDAY AND TUESDAY NIGHT ALONG THE NORTHERN PERIPHERY OF SLOWLY EXPANDING SOUTHEAST CONUS UPPER RIDGING. THIS POSITIONING WILL EFFECTIVELY ANCHOR THE SURFACE REFLECTION OF THE EXITING COLD FRONTAL BOUNDARY INVOF OF THE OH/MI BORDER DURING THIS TIME. CONTINUED CONVERGENCE ACROSS THE FRONTAL SLOPE AUGMENTED BY A COMBINATION OF BOTH LOW AMPLITUDE IMPULSES AND/OR REMNANT MCV ACTIVITY AND SOME RENEWED ISENTROPIC LIFT WILL SUPPORT AT LEAST A CHANCE FOR SHOWER DEVELOPMENT. THIS PATTERN PROVIDING THE USUAL CHALLENGES IN DEFINING BOTH POSSIBLE COVERAGE AND TIMING...SOME DEPENDENCE ON HOW NOCTURNAL CONVECTION EXPECTED TO BLOSSOM OVER THE MIDWEST TONIGHT EVENTUALLY SPILLS DOWNSTREAM. GREATER POTENTIAL WILL LIE TOWARD THE SOUTH GIVEN THE FRONTAL POSITIONING AND LESS INFLUENCE FROM DRIER AIR NOSING IN FROM THE NORTH. RIBBON OF HIGHEST THETA-E WILL RESIDE ALONG AND SOUTH OF THE BOUNDARY...BUT OVERALL MOISTURE QUALITY CERTAINLY REMAINS ADEQUATE /PW HOLDING AT 1.3"/. LOW LEVEL ANTICYCLONIC FLOW FILLING ACROSS NORTHERN LOWER MI WILL SUSTAIN A MORE STABLE LOW LEVEL EASTERLY FLOW LOCALLY. THIS WILL KEEP INSTABILITY AT A MINIMUM...CONFINED ABOVE A FIRM INVERSION NOW IN PLACE UP THROUGH 900 MB. THIS EASTERLY FLOW COMBINED WITH A HIGHER DEGREE OF CLOUD COVER AND PROSPECTS FOR SHOWERS TO DISRUPT THE HEATING CYCLE WILL CAP HIGHS IN THE LOWER AND MIDDLE 60S ON TUESDAY. UPPER RIDGE AXIS WILL MOVE ACROSS SE MICHIGAN WEDNESDAY AND WEDNESDAY NIGHT. A SLOWER LOW LEVEL RESPONSE WILL LIKELY RETAIN A LONGER RESIDENCE TIME OF EAST/SE FLOW LOCALLY...LEAVING THE FRONTAL SLOPE DRAPED OVER OR JUST TO THE SOUTHWEST FOR THE BULK OF THE DAYTIME PERIOD. 00Z MODEL GUIDANCE HOLDING WITH JUST VERY LIMITED PRECIPITATION POTENTIAL OWING TO BOTH THE DEGREE OF STABILITY/UPPER RIDGE POSITIONING AND LACK OF SHORTWAVE ENERGY/REMNANT CONVECTIVE DEBRIS TO PROVIDE AN ADDITIONAL FOCUS. CERTAINLY PLAUSIBLE A FEW SHOWERS EMERGE AS WEAK ASCENT PERSISTS ALONG THE ELEVATED FRONTAL SLAB /900-700 MB/...BUT CONFIDENCE REMAINS ON THE LOWER END AND WILL MAINTAIN A LIMITED MENTION AT THIS TIME. THE UPWARD ADJUSTMENT IN HEIGHTS AND GREATER PROSPECTS FOR SOME PEAKS OF SUN WILL NUDGE HIGHS UP A CATEGORY OR TWO RELATIVE TO TUESDAY. HIGHS UPPER 60S TO LOWER 70S. A PERIOD OF DEEPER SOUTHWEST FLOW FOR THE LATTER HALF OF THE WEEK...DICTATED BY HIGH AMPLITUDE TROUGHING ACROSS THE INTERMOUNTAIN WEST AND UPPER RIDGING EDGING TOWARD THE EAST COAST. THIS WILL PROVIDE A MORE NOTEWORTHY INCREASE IN THE TEMPERATURES FOR BOTH THURSDAY AND FRIDAY. HIGHS MAKING A RUN TOWARD THE LOWER 80S BY FRIDAY. WARM/DRY PROFILE WITH NEGLIGIBLE FORCING WILL MINIMIZE CONVECTIVE CHANCES ON THURSDAY. SIMILAR ENVIRONMENT ON FRIDAY PER 00Z GFS BUT ECMWF PROVIDES A PROGRESSIVE SOLUTION RUNNING A LEAD WAVE OVER THE RIDGE AND DRAGGING THE ATTENDANT COLD FRONT INTO THE REGION BY PEAK HEATING. LOWER END CHANCE POPS REMAIN APPROPRIATE TO HIGHLIGHT THE POTENTIAL AND UNCERTAINTY FOR THE NEXT ROUND OF SHOWERS/THUNDERSTORMS DURING THIS TIME WINDOW. MARINE... POTENTIAL FOR THUNDERSTORMS ACROSS ALL MARINE AREAS THROUGH TONIGHT AS A COLD FRONT MOVES ACROSS THE REGION. SOUTHWEST WINDS TODAY WILL SHIFT TO NORTHWESTERLY BY EVENING. LIGHT EASTERLY WINDS WILL THEN DEVELOP FOR TUESDAY AND WEDNESDAY AS HIGH PRESSURE BUILDS ACROSS THE NORTHERN GREAT LAKES. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......SF AVIATION.....BT SHORT TERM...BT LONG TERM....MR MARINE.......MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
739 AM EDT MON MAY 4 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 449 AM EDT MON MAY 4 2015 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD SHALLOW TROUGH ACROSS SRN CANADA INTO THE NORTH CENTRAL CONUS. A SHORTWAVE TROUGH LIFTING NE THROUGH NRN ONTARIO WAS DRAGGING A COLD FRONT THROUGH ERN UPPER MICHIGAN. THE PCPN ASSOCIATED WITH THE FRONT AND 700-300 MB QVECTOR CONV AHEAD OF THE MID LEVEL TROUGH HAD MOVED SOUTH AND EAST OF THE CWA. BEHIND THE FRONT...DRIER AIR WAS QUICKLY MOVING INTO UPPER MICHIGAN...PER 00Z KINL SOUNDING...WITH DEWPOINTS DROPPING INTO THE 30S OVER THE NORTH AND WEST. IR LOOP SHOWED MID AND HIGH CLOUDS LINGERING OVER MOST OF UPPER MICHIGAN WITH CLEARING ONLY OVER THE FAR WEST. TODAY...AS HIGH PRES BUILDS FROM THE NRN PLAINS INTO THE WRN GREAT LAKES...EXPECT THE CLOUDS TO DEPART EARLY LEAVING MOSTLY SUNNY SKIES WITH ONLY FEW/SCT CU DEVELOPING. MIXING TO AROUND 5K FEET INLAND WITH 850 MB TEMPS AROUND 5C WILL SUPPORT HIGHS IN THE MID TO UPPER 60S. THE WEAK NRLY WINDS OFF OF LAKE SUPERIOR WILL KEEP READINGS IN THE 50S CLOSER TO THE SHORE. WITH AFTERNOON DEWPOINTS FALLING INTO THE MID TO UPPER 20S...INLAND RH VALUES WILL FALL OFF TO 20 TO 25 PCT. TONIGHT...HIGH PRES WILL DOMINATE KEEPING CONDITIONS DRY MON NIGHT THROUGH TUE. WITH PWATS DROPPING DOWN BELOW.25 INCH AND LIGHT WINDS EXPECTED UNDER THE SFC HIGH...MIN TEMPS NEAR FREEZING ARE EXPECTED AT THE TYPICAL INLAND COLD LOCATIONS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 330 AM EDT MON MAY 4 2015 TUESDAY...SFC HIGH PRESSURE ACROSS LAKE SUPERIOR AND UPPER MI AHEAD OF MID-LEVEL RIDGING OVER THE NORTHERN PLAINS WILL RESULT IN SUNNY SKIES...THOUGH A FEW HIGH CLOUDS MAY FILTER IN THE FROM SE DURING THE AFTERNOON. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...MODELS HAVE TRENDED DOWN A LITTLE BIT ON THE QPF FOR LATE TUE NIGHT INTO WED ALONG AN 850 HPA WARM FRONT/300-310K ISENTROPIC LIFT. WITH STOUT MID-LEVEL RIDGING MOVING OVER THE UPPER MS VALLEY AND OVERALL DEEPER MOISTURE AND LOW- LEVEL MOISTURE TRANSPORT REMAINING CONFINED TO THE WESTERN CWA...KEPT ONLY LOW CHANCE POPS FOR THE WEST HALF. PRECIP CHANCES DIMINISH TO LOW-END SLIGHT CHANCE ACROSS THE WEST WED NIGHT AS THE LOW-LEVEL WAA EXITS TO THE NE AND MID-LEVEL FORCING WELL SW OF THE REGION STRUGGLES TO WORK INTO THE RIDGE. THURSDAY THROUGH FRIDAY...DEEP TROUGHING MOVING ONTO THE PACIFIC NW LATE TODAY WILL HELP KICK A SLOW-MOVING MID-LEVEL TROUGH/LOW ACROSS THE SW STATES BY MID WEEK. THIS WILL CONSOLIDATE A BROAD SFC LOW ACROSS THE WESTERN STATES ON WED. THE LOW IS PROGGED TO TRACK NNE ACROSS THE NORTHERN PLAINS BEFORE BEGINNING TO TURN EASTWARD OVER WESTERN ONTARIO. IT REMAINS TO BE SEEN HOW WELL THE MID-LEVEL TROUGH CAN ERODE THE RIDGE OVER THE UPPER MS VALLEY AND UPPER GREAT LAKES BY THURSDAY. THE ECMWF IS THE MOST PROGRESSIVE WITH THE OVERALL PATTERN...WITH THE TROUGH AND SFC COLD FRONT CLEARING THE CWA BY FRIDAY EVENING. MEANWHILE...THE CANADIAN GEM IS QUITE SLOW...SENDING THE TROUGH WELL NORTH AND WASHING OUT THE COLD FRONT ACROSS THE CWA ON SATURDAY. THE GFS FALLS BETWEEN THESE TWO SOLUTIONS...BUT LEANS TOWARD THE ECMWF. THERE SHOULD BE ENOUGH MID-LEVEL ENERGY TO CHIP AWAY AT THE RIDGE...BUT LIKELY NOT AS FAST AS IS PROGGED BY THE ECMWF. HAVE THEREFORE CHOSEN TO FOLLOW A SOLUTION CLOSE TO THAT OF THE GFS. WITH ALL THAT TAKEN INTO ACCOUNT...SCATTERED SHOWERS AND SOME THUNDERSTORMS SHOULD PUSH INTO THE WESTERN CWA THURSDAY AFTERNOON...AND GRADUALLY SPREAD EASTWARD AS FORCING FROM THE MID- LEVEL WAVE WORKS OVER THE CWA. SCATTERED SHOWERS AND THUNDERSTORMS SHOULD THEN CONTINUE THROUGH MOST OF FRIDAY BEFORE THE COLD FRONT ENDS CHANCES ACROSS THE WEST FRIDAY EVENING. SATURDAY AND SUNDAY...AFTER A LULL IN PRECIP ON SATURDAY...A LARGE PORTION OF THE MAIN WESTERN TROUGH WILL TRACK ACROSS THE PLAINS AND BRING INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS THE CWA FOR SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 738 AM EDT MON MAY 4 2015 EXPECT VFR CONDITIONS AT ALL 3 TAF SITES THIS FCST PERIOD WITH DRY HIGH PRESSURE BUILDING INTO THE WESTERN GREAT LAKES. THERE MAY BE SOME GUSTY WINDS AFTER SUNRISE INTO THE EARLY AFTERNOON UNDER THE SHARPER PRES GRADIENT BETWEEN THE INCOMING HIGH AND DEPARTING COLD FRONT...BUT WINDS SHOULD TREND LIGHTER TOWARD THE END OF THE DAY WITH THE ARRIVAL OF THE WEAKER GRADIENT AS WELL AS LOSS OF DAYTIME HEATING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 449 AM EDT MON MAY 4 2015 FOG IS EXPECTED TO LINGER THIS MORNING OVER THE E HALF OF LAKE SUPERIOR BUT WILL DISSIPATE AS HIGH PRESSURE AND DRIER AIRS BUILDS OVER THE UPPER LAKES FROM THE W-NW TODAY. EXPECT THE HIGH TO DRIFT INTO SE ONTARIO LATER TUESDAY INTO WEDNESDAY...AS ANOTHER AREA OF HIGH PRESSURE MOVES INTO NW ONTARIO...AD A LOW DEVELOPS OVER THE PLAINS. A LOW PRESSURE CENTER WILL MOVE THROUGH THE NRN PLAINS ON THURSDAY WHILE THE ONTARIO HIGH DRIFTS ACROSS HUDSON BAY INTO QUEBEC. THE LOW WILL DRAG A TROUGH ACROSS THE UPPER GREAT LAKES REGION THURSDAY NIGHT THROUGH FRIDAY. ALTHOUGH SRLY WINDS WILL INCREASE FROM THU INTO THU NIGHT...WINDS ARE EXPECTED TO REMAIN AT OR BELOW 20 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KLUBER AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
708 AM EDT MON MAY 4 2015 .AVIATION... A WEAKENING PATTERN OF SHOWERS WILL MOVE THE REST OF THE WAY THROUGH SE MICHIGAN DURING THE MORNING AS MOISTURE BUILDS AHEAD OF THE COLD FRONT. THE FRONT IS ON A SLIGHTLY SLOWER SCHEDULE TO MOVE THROUGH THE REGION DURING THE AFTERNOON AND EVENING...AND WILL BECOME THE FOCUS FOR REDEVELOPMENT OF SHOWERS AND POSSIBLY THUNDERSTORMS MAINLY SOUTH OF MBS AND FNT. INTERVALS OF MVFR RESTRICTION ARE LIKELY WITH THE SHOWERS BUT THUNDERSTORM TIMING AND COVERAGE NEEDS FURTHER REFINEMENT BEFORE INCLUSION IN THE FORECAST AT ANY ONE TERMINAL. NORTHWEST LOW LEVEL FLOW POST FRONT WILL VEER TOWARD THE NORTHEAST DURING THE EVENING...AND THEN TOWARD THE EAST OVERNIGHT. VFR IS EXPECTED AS DRY AND COOLER AIR MOVES IN FROM THE NORTH. SHOWERS WILL REMAIN POSSIBLE IN THE DTW AREA AS THE FRONT STALLS NEAR THE OHIO BORDER THROUGH TUESDAY MORNING. FOR DTW...VFR WILL PERSIST THROUGH A WEAKENING PATTERN OF SHOWERS DURING THE MORNING. A BREAK IN THE PRECIPITATION WILL THEN PRECEDE A COLD FRONT THAT IS ON A SLIGHTLY LATER SCHEDULE TO MOVE THROUGH THE DTW AREA DURING LATE AFTERNOON TO EARLY EVENING. THIS WILL PROVIDE A BETTER WINDOW FOR THUNDERSTORM POTENTIAL COMPARED TO POINTS NORTH BUT TIMING AND COVERAGE STILL NEED REFINEMENT BEFORE STORMS ARE ADDED TO THE FORECAST. THE FRONT IS STILL EXPECTED TO STALL NEAR THE OHIO BORDER WHICH WILL KEEP RAIN IN THE FORECAST OVERNIGHT THROUGH TUESDAY MORNING. //DTW THRESHOLD PROBABILITIES... * MEDIUM FOR CEILING AOB 5000FT THIS AFTERNOON AND TONIGHT. * LOW FOR THUNDERSTORMS THIS AFTERNOON AND EVENING. && .PREV DISCUSSION...ISSUED 352 AM EDT MON MAY 4 2015 SHORT TERM... TODAY AND TONIGHT AFTER AN OUTSTANDING WEEKEND OF DRY AND WARM WEATHER...AN ACTIVE PRECIPITATION PATTERN WILL GET UNDERWAY TO START THE WEEK. BEGINNING THIS MORNING...SHOWERS AND A FEW THUNDERSTORMS WILL MARK THE LEADING EDGE OF INCREASED LOW LEVEL MOISTURE ADVANCING THROUGH LOWER MICHIGAN. MORNING COVERAGE WILL BE GREATEST FROM FLINT TO THE TRI CITIES AND NORTHERN THUMB BUT ALL AREAS WILL HAVE AT LEAST A CHANCE OF SHOWERS AS THE MOISTURE SURGE PROGRESSES THROUGH THE REGION. THE COLD FRONT APPROACHING FROM THE WEST WILL THEN TAKE OVER DURING THE AFTERNOON. THAT IS WHEN THE HIGHEST CONCENTRATION OF SHOWERS AND STORMS WILL SHIFT GENERALLY SOUTH OF THE INTERSTATE 69 CORRIDOR THROUGH EARLY EVENING. AFTERNOON THUNDERSTORM POTENTIAL WILL BE STRONGLY DEPENDENT ON RECOVERY OF SURFACE BASED INSTABILITY THAT WILL BE LIMITED BY MORNING CLOUDS AND PRECIPITATION. RADAR OBSERVATIONS INDICATE SHOWERS AND A FEW THUNDERSTORMS EXPANDING IN COVERAGE OVER SW LOWER MICHIGAN SINCE MIDNIGHT. THIS IS OCCURRING ON THE LEADING EDGE OF THE LOW LEVEL MOISTURE AXIS WITH A MODESTLY INCREASING LOW LEVEL JET...BOTH OF WHICH ARE GENERATING A TYPICAL PATTERN OF NOCTURNAL ELEVATED INSTABILITY. THE 00Z MODELS HAVE A REASONABLE HANDLE ON THIS SCENARIO JUDGING BY THETA-E AND WIND FIELDS IN THE 850-700 MB LAYER. PREFER THOSE THAT ARE MORE BULLISH ON THE MAINTENANCE OF MORNING QPF OVER SE MICHIGAN NOW THAT MOISTURE ADVECTION IS PROVING ADEQUATE TO GENERATE CONVECTION. FOR NOW...PLAN TO NUDGE MORNING POPS UP INTO THE CATEGORICAL RANGE IN THE TRI CITIES AND INTO HIGH LIKELY SOUTHWARD ALONG THE U.S. 23 CORRIDOR TO ACCOUNT FOR SOUTHWARD EXPANSION ALONG THE MOISTURE GRADIENT. THERE IS GOOD MODEL AGREEMENT INDICATING THE COLD FRONT IS ON PACE TO BE THROUGH THE TRI CITIES AND NORTHERN THUMB BY EARLY AFTERNOON. EXPECT IT WILL TAKE UNTIL THEN FOR BOUNDARY LAYER TEMPERATURE RECOVERY TO OCCUR ON THE HEELS OF THE MORNING SHOWERS AND CONVECTIVE CLOUD DEBRIS. THIS SUGGESTS LEANING THE FORECAST TOWARD THE LOWER END OF THE MODEL RANGE FOR SURFACE BASED CAPE. THE NAM CONTINUES TO ADVERTISE CAPE REACHING 1500-1800 J/KG SUBJECT TO SURFACE DEWPOINT RISING INTO THE LOWER 60S AS SURFACE TEMPERATURE RECOVERS INTO THE MID TO UPPER 70S. THE RAP AND GFS ALSO INDICATE SURFACE DEWPOINT REACHING THE LOWER 60S BUT PRODUCE CAPE CLOSER TO 1000 J/KG WITH MAIN DIFFERENCE BEING SHALLOWER MID LEVEL LAPSE RATES. THIS IS GENERALLY PREFERRED CONSIDERING THE WARM LARGE SCALE UPPER AIR PATTERN...ESPECIALLY FOR THIS TIME OF YEAR. THE ONE WILD CARD TO MONITOR IS THE HINT OF MCV DEVELOPMENT OVER THE MIDWEST THAT COULD HELP A FEW STORMS OVERACHIEVE. WITH THAT IN MIND...THE SPC OUTLOOK FOR MARGINAL LOOKS REASONABLE BEFORE THE FRONT SETTLES SOUTH OF THE OHIO BORDER BY MIDNIGHT. LONG TERM...TUESDAY THROUGH SUNDAY MID LEVEL WESTERLIES TAKE HOLD TUESDAY AND TUESDAY NIGHT ALONG THE NORTHERN PERIPHERY OF SLOWLY EXPANDING SOUTHEAST CONUS UPPER RIDGING. THIS POSITIONING WILL EFFECTIVELY ANCHOR THE SURFACE REFLECTION OF THE EXITING COLD FRONTAL BOUNDARY INVOF OF THE OH/MI BORDER DURING THIS TIME. CONTINUED CONVERGENCE ACROSS THE FRONTAL SLOPE AUGMENTED BY A COMBINATION OF BOTH LOW AMPLITUDE IMPULSES AND/OR REMNANT MCV ACTIVITY AND SOME RENEWED ISENTROPIC LIFT WILL SUPPORT AT LEAST A CHANCE FOR SHOWER DEVELOPMENT. THIS PATTERN PROVIDING THE USUAL CHALLENGES IN DEFINING BOTH POSSIBLE COVERAGE AND TIMING...SOME DEPENDENCE ON HOW NOCTURNAL CONVECTION EXPECTED TO BLOSSOM OVER THE MIDWEST TONIGHT EVENTUALLY SPILLS DOWNSTREAM. GREATER POTENTIAL WILL LIE TOWARD THE SOUTH GIVEN THE FRONTAL POSITIONING AND LESS INFLUENCE FROM DRIER AIR NOSING IN FROM THE NORTH. RIBBON OF HIGHEST THETA-E WILL RESIDE ALONG AND SOUTH OF THE BOUNDARY...BUT OVERALL MOISTURE QUALITY CERTAINLY REMAINS ADEQUATE /PW HOLDING AT 1.3"/. LOW LEVEL ANTICYCLONIC FLOW FILLING ACROSS NORTHERN LOWER MI WILL SUSTAIN A MORE STABLE LOW LEVEL EASTERLY FLOW LOCALLY. THIS WILL KEEP INSTABILITY AT A MINIMUM...CONFINED ABOVE A FIRM INVERSION NOW IN PLACE UP THROUGH 900 MB. THIS EASTERLY FLOW COMBINED WITH A HIGHER DEGREE OF CLOUD COVER AND PROSPECTS FOR SHOWERS TO DISRUPT THE HEATING CYCLE WILL CAP HIGHS IN THE LOWER AND MIDDLE 60S ON TUESDAY. UPPER RIDGE AXIS WILL MOVE ACROSS SE MICHIGAN WEDNESDAY AND WEDNESDAY NIGHT. A SLOWER LOW LEVEL RESPONSE WILL LIKELY RETAIN A LONGER RESIDENCE TIME OF EAST/SE FLOW LOCALLY...LEAVING THE FRONTAL SLOPE DRAPED OVER OR JUST TO THE SOUTHWEST FOR THE BULK OF THE DAYTIME PERIOD. 00Z MODEL GUIDANCE HOLDING WITH JUST VERY LIMITED PRECIPITATION POTENTIAL OWING TO BOTH THE DEGREE OF STABILITY/UPPER RIDGE POSITIONING AND LACK OF SHORTWAVE ENERGY/REMNANT CONVECTIVE DEBRIS TO PROVIDE AN ADDITIONAL FOCUS. CERTAINLY PLAUSIBLE A FEW SHOWERS EMERGE AS WEAK ASCENT PERSISTS ALONG THE ELEVATED FRONTAL SLAB /900-700 MB/...BUT CONFIDENCE REMAINS ON THE LOWER END AND WILL MAINTAIN A LIMITED MENTION AT THIS TIME. THE UPWARD ADJUSTMENT IN HEIGHTS AND GREATER PROSPECTS FOR SOME PEAKS OF SUN WILL NUDGE HIGHS UP A CATEGORY OR TWO RELATIVE TO TUESDAY. HIGHS UPPER 60S TO LOWER 70S. A PERIOD OF DEEPER SOUTHWEST FLOW FOR THE LATTER HALF OF THE WEEK...DICTATED BY HIGH AMPLITUDE TROUGHING ACROSS THE INTERMOUNTAIN WEST AND UPPER RIDGING EDGING TOWARD THE EAST COAST. THIS WILL PROVIDE A MORE NOTEWORTHY INCREASE IN THE TEMPERATURES FOR BOTH THURSDAY AND FRIDAY. HIGHS MAKING A RUN TOWARD THE LOWER 80S BY FRIDAY. WARM/DRY PROFILE WITH NEGLIGIBLE FORCING WILL MINIMIZE CONVECTIVE CHANCES ON THURSDAY. SIMILAR ENVIRONMENT ON FRIDAY PER 00Z GFS BUT ECMWF PROVIDES A PROGRESSIVE SOLUTION RUNNING A LEAD WAVE OVER THE RIDGE AND DRAGGING THE ATTENDANT COLD FRONT INTO THE REGION BY PEAK HEATING. LOWER END CHANCE POPS REMAIN APPROPRIATE TO HIGHLIGHT THE POTENTIAL AND UNCERTAINTY FOR THE NEXT ROUND OF SHOWERS/THUNDERSTORMS DURING THIS TIME WINDOW. MARINE... POTENTIAL FOR THUNDERSTORMS ACROSS ALL MARINE AREAS THROUGH TONIGHT AS A COLD FRONT MOVES ACROSS THE REGION. SOUTHWEST WINDS TODAY WILL SHIFT TO NORTHWESTERLY BY EVENING. LIGHT EASTERLY WINDS WILL THEN DEVELOP FOR TUESDAY AND WEDNESDAY AS HIGH PRESSURE BUILDS ACROSS THE NORTHERN GREAT LAKES. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....BT SHORT TERM...BT LONG TERM....MR MARINE.......MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
633 AM CDT Mon May 4 2015 .SHORT TERM: (Today and Tonight) Issued at 330 AM CDT Mon May 4 2015 There are 2 main areas with precipitation potential this morning. The first is from southeast/east central MO eastward into IL where low-mid level warm advection has resulted in spotty showers within the last few hours. The GFS and recent runs of the HRRR suggest this potential will persist until around mid morning. The other area is across northeast MO/west central IL extending into parts of central MO. The frontal convection has in general become less organized with one area from eastern IA into northern IL and another cluster in NW MO. Both regions have generated a pre-frontal cold pool and outflow boundary, but its the western-most area in NW MO that bears the most watching. General movement has been to the southeast and some of the hi-res WRFs want to bring this cluster along with some additional development into north-central/central MO this morning. The current cluster is within a region of moisture convergence along the northern terminus of a 40+ kts southwesterly LLJ and weak elevated CAPE. It should encounter a less favorable enviroment as it moves southeast this morning, primarily after 12z, however forcing may be sufficient for scattered showers and thunderstorms within the area highlighted by the hi-res guidance. Otherwise clouds should thin across the entire area during the later half of the morning and into the early afternoon and when combined with the present WAA regime and temps aloft, this should result in another warm day with well above normal highs in the 80s. There are some discrepencies in the guidance on the southward position of the front this afternoon and evening with the RAP and ECMWF showing a bit more southward position into the northern part of the CWA by 00z, while the remainder of the models keep it near or just south of the MO/IA border. I think it will ooze south into the far northern part of the CWA by late afternoon. Present indications are that heating and continued low-level moistening late morning into afternoon will result in moderate instability along the frontal zone. Good low level convergence along the boundary combined with lift associated with a migrating short wave moving across southern IA/northern MO should result in extensive convective development during the later half of the afternoon spanning from KS across northern MO/southern IA into central IL. I am still thinking that the broad and veering southwesterly LLJ will maintain numberous thunderstorms/clusters during the evening with a decided eastward motion. Although the models suggest the front will shift slightly northward overnight I am not so sure this will happen with rain cooled air maintaining its position. However increased ridging aloft both in the low-mid levels suggest that the forecast of a northward shift in the convection overnight is reasonable. The only noticeable change to the pops tonight is to expand the area of slight chances southward a bit to I-70. The GFS and ECMWF QPFs are a bit far south and well into the warm sector and I would think the majority of the convection will reside along the front and northward into the cool air. Glass .LONG TERM: (Tuesday through Sunday) Issued at 330 AM CDT Mon May 4 2015 Not much has changed in thinking from 24 hours ago with respect to the Tuesday through weekend period. The front will make a decided shift northward on Tuesday as ridging aloft continues to build from the lower TN Valley into the upper MS Valley, while across southern sections of the CWA we continue to see the models generate some light QPF. I`m still not sold on it but will maintain low pops in the slight range given the uncertainty. Tuesday still looks to be another day of above normal temps with highs in the 80s. Flow aloft becomes more south-southwest on Wednesday and a lead impulse within this flow will traverse the western CWA prompting an increased threat of showers and thunderstorms across western MO into central MO. Flow aloft becomes southwesterly by Thursday and this regime persists into the weekend ahead of a upper trof/low migrating from the western U.S. and into the central U.S.. The threat of showers and thunderstorms Thursday into the weekend gradually ramps up and spreads west to east due to the active southwest flow aloft with embedded disturbances, moist unstable warm sector, and slowly encroaching cold front. Above normal temperatures should persist through the extended period. Glass && .AVIATION: (For the 12z TAFs through 12z Tuesday Morning) Issued at 625 AM CDT Mon May 4 2015 VFR conditions to persist through forecast period. Main issue will be scattered showers and thunderstorms, especially this morning and again later in the day today. Coverage is scattered this morning, so for now have vcnty shower mention at all sites, except KUIN where have vcnty trw mention as they are closer to frontal boundary and activity firing along outflow boundary. Another round of storms possible late this afternoon and evening for KUIN with frontal boundary in area. Otherwise, south to southwest winds to persist today with gusts to near 20kts at times, before diminishing towards sunset. Specifics for KSTL: VFR conditions to persist through forecast period. Main issue will be scattered showers this morning. Coverage is scattered, so for now have vcnty shower mention in metro area. Otherwise, south to southwest winds to persist today with gusts to near 20kts at times, before diminishing towards sunset. Byrd && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
925 AM MDT MON MAY 4 2015 .UPDATE... FORECAST WAS IN GOOD SHAPE OVERALL. MADE JUST A FEW CHANGES BASED ON LATEST OBSERVED TRENDS AND MODEL GUIDANCE. JET DIVERGENCE FROM RIGHT-REAR QUADRANT OF DEPARTING JET...COMBINED WITH A SHORTWAVE...WAS CREATING SHOWERS OVER SE MT THIS MORNING PER RADAR IMAGERY. NOTED THAT HULETT WY IN NE WY REPORTED MODERATE RAIN FOR A TIME. THE HRRR HAD A GOOD HANDLE ON THIS PRECIPITATION...SO HAVE ADJUSTED POPS A BIT IN THIS AREA TO GO CLOSER TO THIS MODEL. KEPT LINGERING POPS IN THE FAR E AFTER 18Z PER MODELS AS WELL. A FEW RADAR ECHOES WERE ALSO MOVING OFF THE NE BIGHORNS AND APPEARED TO BE GENERATED BY SE UPSLOPE FLOW. WEB CAMS DID NOT SHOW ANY PRECIPITATION...BUT ADDED A LOW POP OVER AND NEAR THE MOUNTAINS THIS MORNING TO COVER POSSIBLE SHOWERS. IN ADDITION...SHOWERS WERE APPROACHING THE SW MOUNTAINS FROM ID ON RADAR...SO HAD LOW POPS OVER THESE MOUNTAINS AS WELL. OTHERWISE...NOT MUCH IN THE WAY OF LIFT WILL BE OVER THE AREA THROUGH TONIGHT. NOTED AIRMASS WAS MOISTENING UP AS PRECIPITABLE WATER S AND SE OF THE AREA HAVE TRENDED UP SINCE YESTERDAY. THIS WAS DUE TO THE STRONG LOW-LEVEL SE FLOW OVER THE AREA. THIS FLOW WAS CREATING GUSTY SE WINDS OVER KSHR AND SE MT THIS MORNING. HAVE ADJUSTED WINDS THROUGH THIS EVENING TO REFLECT LATEST WIND GUIDANCE AND OBSERVED TRENDS. PRECIPITATION WILL BE TERRAIN-DRIVEN THROUGH THIS EVENING AND AFTERNOON/EVENING POPS MATCHED LATEST GUIDANCE. THE SREF CONTINUED TO ADVERTISE SURFACE CAPES OF AT LEAST 500 J/KG THIS AFTERNOON...AND SINCE THUNDER HAS BEEN OCCURRING IN WY WITH SIMILAR CAPES THE PAST FEW AFTERNOONS...HAVE INCREASED THUNDER PROBABILITIES THROUGH THIS EVENING. SHEAR WILL BE WEAK. RAP SOUNDINGS HAVE MIXING TO 700 MB CENTRAL AND W TODAY WITH LESSER MIXING E OF KBIL. HIGH TEMPERATURE FORECAST LOOKED GOOD GIVEN TEMPERATURES ALOFT. RH/S WERE ALSO IN GOOD SHAPE GIVEN THE INCREASING MOISTURE. QUICK GLANCE AT TUE SHOWED SIMILAR CAPES TO TODAY WITH LITTLE SHEAR...AND INCREASING UPPER SUPPORT AHEAD OF THE COLD FRONT. MAY INCREASE CHANCES FOR THUNDER TUE AFTERNOON AFTER SEEING WHAT OCCURS THIS AFTERNOON. ARTHUR && .SHORT TERM...VALID FOR TDY AND TUE... PRECIPITATION CHANCES WILL BE INCREASING THROUGH THE SHORT TERM. DID NOT MAKE MANY CHANGES TO THE PREVIOUS FORECAST AS MODELS CONTINUE TO BE IN FAIRLY GOOD AGREEMENT AND CONSISTENT WITH THEMSELVES. AN UPPER LOW AND TROUGH WILL APPROACH THE PACIFIC NORTHWEST COAST LATE TODAY INTO TUESDAY ALLOWING FOR SOME WEAK RIDGING ALONG WITH A SOUTHWEST FLOW ALOFT TO DEVELOP ACROSS OUR FORECAST AREA. SEVERAL SURFACE LOWS WILL DEVELOP ACROSS THE NORTHERN AND CENTRAL ROCKIES BRINGING A PREDOMINATELY SOUTHEAST SURFACE FLOW RESULTING IN INCREASING LOW-LEVEL MOISTURE ACROSS THE AREA TODAY THROUGH TUESDAY. A FEW DISTURBANCES WILL MOVE ACROSS WYOMING AND FAR SOUTHERN MONTANA THIS AFTERNOON/EVENING AND AGAIN TUESDAY AFTERNOON/EVENING. THESE WILL BRING A CHANCE FOR SHOWERS AND A SLIGHT CHANCE FOR THUNDERSTORMS ACROSS THE MOUNTAINS AND ADJACENT FOOTHILLS TODAY INTO THIS EVENING WITH CHANCES INCREASING ACROSS THE ENTIRE FORECAST AREA TUESDAY AFTERNOON AND EVENING. CAPES TODAY AND TUESDAY WILL BE HIGHER THAN THE PAST COUPLE OF DAYS SO THUNDERSTORM CHANCES WILL BE A BIT HIGHER...ALTHOUGH THEY ARE NOT EXPECTED TO BE WIDESPREAD. TEMPERATURES THIS AFTERNOON AND TUESDAY WILL BE THE WARMEST OF THE ENTIRE WEEK. READINGS IN THE LOWER TO MIDDLE 70S CAN BE EXPECTED TODAY WITH MIDDLE TO UPPER 70S TUESDAY...WITH SLIGHTLY COOLER TEMPERATURES OUT NEAR THE DAKOTA BORDERS. HOOLEY .LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN... THE MODELS THROUGH THE LONG TERM CONTINUE TO SHOW A PATTERN CHANGE TO COOLER AND WETTER...HOWEVER THEY ARE NOT PRESENTING AS ENERGETIC OF A SYSTEM. WEDNESDAY A QUICK SHORTWAVE MOVES JUST SOUTH OF THE AREA...BRINGING SOME INSTABILITY. ALONG WITH IT THERE WILL BE SOME CONVECTIVE ENERGY TO WORK WITH...SO THERE IS A CHANCE FOR THUNDERSTORMS MAINLY DURING THE AFTERNOON. AFTER WEDNESDAY THE CHANCE FOR THUNDERSTORMS DIMINISHES. YESTERDAY THE MODELS WERE SHOWING A CLOSED LOW MOVING OUT OF THE GREAT BASIN THIS WEEKEND. THE LATEST RUNS HAVE BACKED OFF SOME...TO MORE A FILLING LOW/OPEN WAVE MOVING OUT INTO THE HIGH PLAINS. THIS DOES NOT HAVE AS MUCH ENERGY OR THE FORCING THAT MODELS WERE ADVERTISING YESTERDAY. AS SUCH PRECIP THROUGH THE WEEKEND IS LESS. FOR NOW HAVE OPTED TO NOT DO ANYTHING RADICAL TO THE FORECAST FOR THE WEEKEND. CONTINUE THE TREND OF COOLER TEMPERATURES AS MODELS CONTINUE TO SHOW RATHER CLOUDY AND SOMEWHAT RAINY CONDITIONS. REIMER && .AVIATION... SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED IN THE MOUNTAINS TODAY AND THIS EVENING WITH LOCAL OBSCURATIONS. ISOLATED ACTIVITY MAY MOVE OFF THE HIGHER TERRAIN AND INTO NEARBY LOWER ELEVATIONS WITH LOCAL MVFR CONDITIONS...BUT VFR WEATHER WILL OTHERWISE PRE- VAIL TODAY AND TONIGHT. SOUTHEAST WINDS WILL GUST UP TO 30 KT IN SOUTHEASTERN MT TODAY AS WELL. SCHULTZ && .PRELIMINARY POINT TEMP/POPS... TDY TUE WED THU FRI SAT SUN ------------------------------------------------------- BIL 075 050/077 050/063 043/052 040/053 037/054 040/059 1/B 12/T 33/T 34/W 33/W 45/W 53/W LVM 073 042/077 044/063 039/047 035/049 032/052 033/059 2/T 23/T 45/T 55/W 44/W 55/W 53/W HDN 076 045/080 048/064 043/056 038/058 036/058 035/060 1/B 11/B 33/T 33/W 33/W 45/W 43/W MLS 070 047/076 051/064 042/057 039/058 036/056 038/058 1/N 11/B 35/T 33/W 22/W 34/W 44/W 4BQ 067 044/073 049/063 043/057 038/057 035/055 037/056 2/W 11/B 45/T 43/W 32/W 45/W 55/W BHK 063 043/069 049/063 041/055 036/055 032/055 034/054 2/W 01/N 47/T 54/W 22/W 34/W 54/W SHR 070 043/074 048/059 041/054 036/056 034/054 036/055 2/T 12/T 45/T 44/W 43/W 45/W 54/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
550 AM CDT MON MAY 4 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 514 AM CDT MON MAY 4 2015 SIMILAR TO YESTERDAY...THE BIGGEST CHALLENGE WILL BE DETERMINING CHANCES AND TIMING OF SHOWERS/THUNDERSTORMS AS WELL AS THE POTENTIAL FOR STRONG STORMS. ANOTHER CHALLENGE WILL BE DETERMINING HIGH TEMPERATURES FOR TODAY. SYNOPTICALLY...WE CONTINUE THE SPLIT FLOW SCENARIO WHILE WE ARE BETWEEN JET STREAMS. A BROAD NEGATIVELY TILTED MEAN TROUGH IN THE WESTERN UNITED STATES NUDGES A LITTLE CLOSER AS A PERTURBATION A SURFACE BOUNDARY HAS STALLED OVER THE FAR SOUTHEASTERN CWA. A MID- LEVEL PERTURBATION WILL MOVE NORTHEAST OUT OF COLORADO/KANSAS INTO OUR AREA BY MID-DAY. THIS WILL LIKELY SPARK SOME THUNDERSTORM ACTIVITY NEAR AND NORTH OF THE STALLED FRONT. INSTABILITY COULD BE AS HIGH AS 2000 J/KG. MID TO UPPER LEVEL FLOW WILL BE WEAK. BULK SHEAR WILL BE WEAK AT MAYBE 20-30 KTS. THIS WILL BE ENOUGH FOR A MINIMAL SEVERE THREAT...AT LEAST IN OUR SOUTHERN CWA...AND AN ISOLATED TORNADO CAN NOT BE RULED OUT AS LOW-LEVEL SHEAR NEAR WILL BE ENHANCED NEAR AND JUST NORTH OF THE SURFACE BOUNDARY. HIGHS TODAY WILL BE TOUGH. THERE WILL BE A VERY LARGE TEMPERATURE GRADIENT AS THE SURFACE FRONT REMAINS STATIONARY OVER THE SOUTHERN CWA. THERE SHOULD BE PLENTY OF SKY COVER AS MODELS INDICATE AN EXTENSIVE SHIELD OF STRATUS DEVELOPING. TEMPERATURES NORTH OF THE BOUNDARY PROBABLY WILL NOT MAKE IT VERY FAR BECAUSE OF THIS AND HAVE SIDED TOWARD COOLER THAN GUIDANCE NUMBERS FOR HIGHS. WE MAY HAVE A HARD TIME BREAKING 60 IN SOME PLACES. I DECIDED TO GO WITH A BLEND OF THE HI RES NMM AND THE RAP FOR HIGHS...AS THESE MODELS HAVE DONE QUITE WELL LATELY. WENT WITH THE FAIRLY DEPENDABLE SUPERBLEND FOR LOWS TONIGHT. WE COULD ALSO GET SOME DECENT GUSTS TODAY NORTH OF THE BOUNDARY AS THE SURFACE PRESSURE GRADIENT WILL BE A BIT TIGHT. I WENT WITH CONSRAW WIND GUSTS FOR TODAY...WHICH IS GREATER THAN THE STANDARD WIND GUST ALGORITHM. DETERMINING CHANCES OF PRECIPITATION WAS BASED ON ENSEMBLE DATA AS WELL AS SUPERBLEND TRENDS. CONFIDENCE HAS NOT BEEN HIGH FOR CHANCES OF PRECIPITATION AND CONTINUES TO BE LOW FOR TODAY AND TONIGHT. WITH THE AFOREMENTIONED PERTURBATION FOR TODAY AND A BIT OF A LOW-LEVEL JET TONIGHT...ALONG WITH THE BOUNDARY SHIFTING NORTH TONIGHT...WE WILL HAVE A DECENT SHOT AT PRECIPITATION AT ALMOST ANY POINT DURING THE SHORT TERM. ANY THREAT OF STRONG TO SEVERE THUNDERSTORMS SHOULD REMAIN PRIMARILY IN THE AFTERNOON AND EVENING. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 514 AM CDT MON MAY 4 2015 EXPECT UNSETTLED WEATHER THROUGH THE WEEK. THE MAIN WEATHER FEATURE WILL BE AN UPPER LEVEL LOW THAT MOVES FROM THE CENTRAL ROCKIES INTO THE CENTRAL PLAINS AND OPENS THE WAVE AS IT MOVES TO THE NORTHEAST. ANOTHER UPPER LEVEL LOW MOVES INTO THE SOUTHWEST CONUS LATER IN THE WEEK. ON TUESDAY THE UPPER LOW IS STILL IN THE ROCKIES AND A WAVE MOVES INTO THE PLAINS AHEAD OF THE UPPER LOW. THE BEST CHANCE FOR THUNDERSTORMS WILL BE IN THE WESTERN PART OF THE AREA CLOSER TO THE UPPER WAVE. BY TUESDAY NIGHT THE WAVE MOVES ONTO THE PLAINS AND STARTS TO OPEN. THE THUNDERSTORMS SHOULD BE ACROSS THE ENTIRE AREA. WEDNESDAY INTO WEDNESDAY NIGHT THE UPPER WAVE IS NEAREST TO THE FORECAST AREA. THIS LOOKS TO BE SOME OF THE BEST CHANCES FOR THUNDERSTORMS. DURING THE AFTERNOON AND EVENING HOURS...THE MUCAPE INCREASES TO OVER 1500 J/KG AND SOME OF THESE STORMS COULD BE STRONG TO SEVERE. THE INITIAL UPPER WAVE MOVES TO THE NORTH ON THURSDAY AND EVEN THOUGH THERE COULD BE SOME SHOWERS AND THUNDERSTORMS AROUND...THE CHANCES WILL BE A LITTLE LESS THAN BEFORE. BY THURSDAY NIGHT THE NEXT UPPER LOW IN THE SOUTHWEST CONUS AND THE FIRST WAVE FROM THIS WAVE STARTS TO AFFECT THE AREA THURSDAY NIGHT INTO FRIDAY. FRIDAY NIGHT INTO SATURDAY THE UPPER LOW CONTINUES TO DRIFT TO THE EAST AND UPPER LEVEL WAVES CONTINUE TO MOVE INTO THE AREA...AND AS THE UPPER LOW MOVES INTO THE PLAINS SATURDAY NIGHT INTO SUNDAY THERE CONTINUES TO BE CHANCES FOR THUNDERSTORMS. TEMPERATURES THROUGH THE PERIOD WILL BE AT LEAST SOMEWHAT VARIABLE. TUESDAY THROUGH THURSDAY WILL BE WARM. THEN A WEAK COLD FRONT MOVES THROUGH THE AREA THURSDAY AFTERNOON AND EVENING BRINGING COOLER TEMPERATURES FOR FRIDAY. SATURDAY AND SUNDAY WILL REMAIN A LITTLE COOLER BUT STILL AROUND OR EVEN ABOVE NORMAL TEMPERATURES ARE EXPECTED. && .AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 548 AM CDT MON MAY 4 2015 AS A FRONT STALLS WELL SOUTH OF THE TERMINALS...A STRATUS DECK IS EXPECTED TO CONTINUE DEVELOPING AND SOCK US IN WITH SKY COVER. CONFIDENCE IS NOT AS HIGH AS TO HOW QUICKLY THIS DECK WILL LOWER. THERE COULD BE SOME ELEVATED THUNDERSTORMS...ESPECIALLY TOWARD THIS AFTERNOON/EVENING...BUT COVERAGE IS UNCERTAIN. VISIBILITY COULD BE SIGNIFICANTLY LESS IN A THUNDERSTORM...BUT SINCE PREDICTABILITY IS SO LOW...ANYTHING SPECIFIC HAS BEEN LEFT OUT OF THIS FORECAST. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...HEINLEIN LONG TERM...JCB AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
516 AM CDT MON MAY 4 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 514 AM CDT MON MAY 4 2015 SIMILAR TO YESTERDAY...THE BIGGEST CHALLENGE WILL BE DETERMINING CHANCES AND TIMING OF SHOWERS/THUNDERSTORMS AS WELL AS THE POTENTIAL FOR STRONG STORMS. ANOTHER CHALLENGE WILL BE DETERMINING HIGH TEMPERATURES FOR TODAY. SYNOPTICALLY...WE CONTINUE THE SPLIT FLOW SCENARIO WHILE WE ARE BETWEEN JET STREAMS. A BROAD NEGATIVELY TILTED MEAN TROUGH IN THE WESTERN UNITED STATES NUDGES A LITTLE CLOSER AS A PERTURBATION A SURFACE BOUNDARY HAS STALLED OVER THE FAR SOUTHEASTERN CWA. A MID- LEVEL PERTURBATION WILL MOVE NORTHEAST OUT OF COLORADO/KANSAS INTO OUR AREA BY MID-DAY. THIS WILL LIKELY SPARK SOME THUNDERSTORM ACTIVITY NEAR AND NORTH OF THE STALLED FRONT. INSTABILITY COULD BE AS HIGH AS 2000 J/KG. MID TO UPPER LEVEL FLOW WILL BE WEAK. BULK SHEAR WILL BE WEAK AT MAYBE 20-30 KTS. THIS WILL BE ENOUGH FOR A MINIMAL SEVERE THREAT...AT LEAST IN OUR SOUTHERN CWA...AND AN ISOLATED TORNADO CAN NOT BE RULED OUT AS LOW-LEVEL SHEAR NEAR WILL BE ENHANCED NEAR AND JUST NORTH OF THE SURFACE BOUNDARY. HIGHS TODAY WILL BE TOUGH. THERE WILL BE A VERY LARGE TEMPERATURE GRADIENT AS THE SURFACE FRONT REMAINS STATIONARY OVER THE SOUTHERN CWA. THERE SHOULD BE PLENTY OF SKY COVER AS MODELS INDICATE AN EXTENSIVE SHIELD OF STRATUS DEVELOPING. TEMPERATURES NORTH OF THE BOUNDARY PROBABLY WILL NOT MAKE IT VERY FAR BECAUSE OF THIS AND HAVE SIDED TOWARD COOLER THAN GUIDANCE NUMBERS FOR HIGHS. WE MAY HAVE A HARD TIME BREAKING 60 IN SOME PLACES. I DECIDED TO GO WITH A BLEND OF THE HI RES NMM AND THE RAP FOR HIGHS...AS THESE MODELS HAVE DONE QUITE WELL LATELY. WENT WITH THE FAIRLY DEPENDABLE SUPERBLEND FOR LOWS TONIGHT. WE COULD ALSO GET SOME DECENT GUSTS TODAY NORTH OF THE BOUNDARY AS THE SURFACE PRESSURE GRADIENT WILL BE A BIT TIGHT. I WENT WITH CONSRAW WIND GUSTS FOR TODAY...WHICH IS GREATER THAN THE STANDARD WIND GUST ALGORITHM. DETERMINING CHANCES OF PRECIPITATION WAS BASED ON ENSEMBLE DATA AS WELL AS SUPERBLEND TRENDS. CONFIDENCE HAS NOT BEEN HIGH FOR CHANCES OF PRECIPITATION AND CONTINUES TO BE LOW FOR TODAY AND TONIGHT. WITH THE AFOREMENTIONED PERTURBATION FOR TODAY AND A BIT OF A LOW-LEVEL JET TONIGHT...ALONG WITH THE BOUNDARY SHIFTING NORTH TONIGHT...WE WILL HAVE A DECENT SHOT AT PRECIPITATION AT ALMOST ANY POINT DURING THE SHORT TERM. ANY THREAT OF STRONG TO SEVERE THUNDERSTORMS SHOULD REMAIN PRIMARILY IN THE AFTERNOON AND EVENING. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 514 AM CDT MON MAY 4 2015 EXPECT UNSETTLED WEATHER THROUGH THE WEEK. THE MAIN WEATHER FEATURE WILL BE AN UPPER LEVEL LOW THAT MOVES FROM THE CENTRAL ROCKIES INTO THE CENTRAL PLAINS AND OPENS THE WAVE AS IT MOVES TO THE NORTHEAST. ANOTHER UPPER LEVEL LOW MOVES INTO THE SOUTHWEST CONUS LATER IN THE WEEK. ON TUESDAY THE UPPER LOW IS STILL IN THE ROCKIES AND A WAVE MOVES INTO THE PLAINS AHEAD OF THE UPPER LOW. THE BEST CHANCE FOR THUNDERSTORMS WILL BE IN THE WESTERN PART OF THE AREA CLOSER TO THE UPPER WAVE. BY TUESDAY NIGHT THE WAVE MOVES ONTO THE PLAINS AND STARTS TO OPEN. THE THUNDERSTORMS SHOULD BE ACROSS THE ENTIRE AREA. WEDNESDAY INTO WEDNESDAY NIGHT THE UPPER WAVE IS NEAREST TO THE FORECAST AREA. THIS LOOKS TO BE SOME OF THE BEST CHANCES FOR THUNDERSTORMS. DURING THE AFTERNOON AND EVENING HOURS...THE MUCAPE INCREASES TO OVER 1500 J/KG AND SOME OF THESE STORMS COULD BE STRONG TO SEVERE. THE INITIAL UPPER WAVE MOVES TO THE NORTH ON THURSDAY AND EVEN THOUGH THERE COULD BE SOME SHOWERS AND THUNDERSTORMS AROUND...THE CHANCES WILL BE A LITTLE LESS THAN BEFORE. BY THURSDAY NIGHT THE NEXT UPPER LOW IN THE SOUTHWEST CONUS AND THE FIRST WAVE FROM THIS WAVE STARTS TO AFFECT THE AREA THURSDAY NIGHT INTO FRIDAY. FRIDAY NIGHT INTO SATURDAY THE UPPER LOW CONTINUES TO DRIFT TO THE EAST AND UPPER LEVEL WAVES CONTINUE TO MOVE INTO THE AREA...AND AS THE UPPER LOW MOVES INTO THE PLAINS SATURDAY NIGHT INTO SUNDAY THERE CONTINUES TO BE CHANCES FOR THUNDERSTORMS. TEMPERATURES THROUGH THE PERIOD WILL BE AT LEAST SOMEWHAT VARIABLE. TUESDAY THROUGH THURSDAY WILL BE WARM. THEN A WEAK COLD FRONT MOVES THROUGH THE AREA THURSDAY AFTERNOON AND EVENING BRINGING COOLER TEMPERATURES FOR FRIDAY. SATURDAY AND SUNDAY WILL REMAIN A LITTLE COOLER BUT STILL AROUND OR EVEN ABOVE NORMAL TEMPERATURES ARE EXPECTED. && .AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1256 AM CDT MON MAY 4 2015 AS A FRONT STALLS WELL SOUTH OF THE TERMINALS...A STRATUS DECK IS EXPECTED TO MOVE IN AND SOCK US IN WITH SKY COVER. THERE COULD BE SOME ELEVATED THUNDERSTORMS...ESPECIALLY TOWARD MONDAY AFTERNOON/EVENING...BUT COVERAGE IS UNCERTAIN. VISIBILITY COULD BE SIGNIFICANTLY LESS IN A THUNDERSTORM...BUT SINCE PREDICTABILITY IS SO LOW...ANYTHING SPECIFIC HAS BEEN LEFT OUT OF THIS FORECAST. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...HEINLEIN LONG TERM...JCB AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
723 AM EDT MON MAY 4 2015 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO DRIFT SLOWLY OFFSHORE EARLY TO MID-WEEK...PROVIDING SUNSHINE AND SEASONABLE MAY TEMPERATURES. A COASTAL LOW IS EXPECTED TO FORM IN THE BAHAMAS MID-WEEK...AND MEANDER ALONG THE SOUTHEAST COAST THROUGH THE END OF THE WEEK AND INTO NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM MONDAY...DRY AND SEASONABLE WEATHER WILL CONTINUE AS HIGH PRESSURE SLIPS FARTHER OFF SHORE WHILE CONTINUING TO RIDGE BACK INTO THE CAROLINAS. THIS WILL PROVIDE A LIGHT RETURN FLOW WITH A SLIGHT INCREASE IN MOISTURE. TEMPS DROPPING EARLY THIS MORNING WILL CREATE SOME VERY SHALLOW FOG BUT OVERALL COLUMN WILL REMAIN VERY DRY WITH ONLY LIMITED LOW LEVEL MOISTURE. A MID TO UPPER RIDGE TRIES TO BUILD OVERHEAD...BUT A SHORTWAVE RIDING DOWN FROM THE NW WILL DISRUPT THIS RIDGE AS IT MOVES SLOWLY OVER THE COASTAL CAROLINAS THROUGH THIS AFTERNOON WITH TROUGH BECOMING STRETCHED OUT ALONG THE COAST TONIGHT. AS THIS SHORTWAVE MOVES THROUGH IT WILL PRODUCE SOME PASSING MID LEVEL CLOUDS. THE LIGHT RETURN FLOW AROUND THE SFC HIGH WILL COMBINE WITH AFTERNOON SEA BREEZE TO GIVE IT A STRONG PUSH INLAND THROUGH THE AFTERNOON. CONVERGENCE ALONG THE SEA BREEZE AND THE WESTERN PERIPHERY OF HIGH PRESSURE WILL HELP BUILD SOME AFTERNOON CU. THE SHORTWAVE SHOULD ACT TO ENHANCE THE VERTICAL GROWTH A BIT...BUT A STRONG SUBSIDENCE INVERSION AROUND 8-9 K FT WILL CAP OFF THE CLOUDS AND LIMIT CHC OF SHWRS. THE HRRR TRIES TO GENERATE A FEW STRAY SHOWERS INLAND THIS AFTERNOON BUT BELIEVE THIS WILL JUST END UP BEING CLUSTERS OF CU. HUGE DIURNAL RANGES WILL CONTINUE WITH TEMPS STARTING OUT IN THE MID 50S THIS MORNING AND REACHING UP TO AROUND 80 EXCEPT SLIGHTLY COOLER AT THE BEACHES. CONTINUED ON SHORE FLOW AROUND HIGH WILL SUPPORT A SLOW RISE IN DEWPOINTS TONIGHT AFTER A DIURNAL DROP THIS AFTERNOON IN DEEPER MIXING. THIS WILL KEEP OVERNIGHT LOWS A FEW DEGREES HIGHER...BUT STILL DOWN TO 55 TO 60 MOST PLACES WITH IDEAL RADIATIONAL COOLING CONDITIONS UNDER CLEAR SKIES AND NEAR CALM WINDS. MAY SEE SOME PATCHY SHALLOW GROUND FOG AGAIN TONIGHT AS TEMPS DROP OUT BUT COLUMN WILL BE VERY DRY ABOVE THE SURFACE. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...BERMUDA HIGH ON TUESDAY WILL RETREAT WEDNESDAY AHEAD OF DISTURBANCE EMERGING FROM THE CARIBBEAN AND THE BAHAMAS. MID LEVEL RIDGING IN PLACE ABOVE THE BERMUDA HIGH TUE WILL MAINTAIN WARM AND DRY CONDITIONS ACROSS THE AREA WITH ONLY PATCHES OF SHALLOW AFTERNOON CU. ONSHORE FLOW WILL CONTINUE KEEPING TEMPS NEAR THE COAST AROUND CLIMO WHILE INLAND AREAS WARM UP A BIT. SECOND HALF OF THE PERIOD STARTS TO GET INTERESTING AS THE SYSTEM EMERGING FROM THE BAHAMAS WILL TRY AND COALESCE INTO A WELL DEFINED LOW. THE GOING WILL INITIALLY BE SLOW AND THE LACK OF STEERING FLOW ALOFT IS LIKELY TO KEEP THE SYSTEM SOUTH OF THE AREA THROUGH THE END OF THE PERIOD. STILL A LOT OF UNCERTAINTY REGARDING THIS SYSTEM AND WHILE IT MAY LEAD TO AN INCREASE IN CLOUD COVER...ESPECIALLY ALONG THE COAST WED NIGHT...DO NOT THINK IT WOULD DIRECTLY AFFECT THE REGION BEFORE THE END OF THE PERIOD. THUS WILL MAINTAIN THE DRY FORECAST WITH HIGHS AROUND CLIMO AND LOWS A BIT ABOVE CLIMO. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 3 AM MONDAY...LONG TERM PERIOD WILL BE DOMINATED BY THE LOW EVOLVING OFF THE SOUTHEAST COAST MID TO LATE WEEK. GUIDANCE CONTINUES TO STRUGGLE WITH THIS SYSTEM...MAINLY DUE TO THE LACK OF ANY REAL STEERING FLOW ALOFT. HOWEVER SOME SOLUTIONS SEEM HARD TO BUY. FOR INSTANCE THE LOW DEEPENING AND MOVING UP THE COAST SEEMS THE LEAST LIKELY OUTCOME GIVEN THE 5H RIDGING TO THE NORTH. DO THINK THE LOW COULD GRADUALLY STRENGTHEN THROUGH THE PERIOD. ALTHOUGH THE WATER TEMPS WITHIN THE GULF STREAM ARE AROUND 80 AND SHEAR SHOULD BE WEAK TO NONEXISTENT THERE ARE SEVERAL FACTORS THAT WOULD LIMIT STRENGTHENING. A LACK OF DIFFLUENCE ALOFT EARLY IN THE PERIOD AND THE LARGE SWATH OF SEA SURFACE TEMPS OUTSIDE THE GULF STREAM IN THE 60S BEING THE BIGGEST. SO WHILE SOME DEVELOPMENT OF THIS SYSTEM IS EXPECTED A FULL BLOWN TROPICAL SYSTEM SEEMS TO BE A LONG SHOT. INSTEAD THE SYSTEM WILL PROBABLY ACQUIRE SOME TROPICAL CHARACTERISTICS BUT REMAIN QUITE WEAK AS IT WANDERS OVER THE WATERS OFF THE SOUTHEAST COAST. WORTH NOTING A LOT OF THE GFS ENSEMBLES TAKE THE WEAK LOW INTO FL OR SOUTHERN GA...SOMETHING WHICH A FAIR NUMBER OF THE MEMBERS HAVE BEEN CONSISTENTLY SHOWING OVER THE LAST FEW DAYS. LOCALLY IMPACTS THROUGH THE PERIOD WILL BE NORTHEAST FLOW...WITH SOME ENHANCEMENT LATER IN THE WEEK AND AN INCREASE IN LOW LEVEL MOISTURE. THIS SHOULD BRING ABOUT AN INCREASE IN PRECIP CHANCES...ESPECIALLY ALONG THE COAST...AS THE WEEK WEARS ON. GIVEN THE LOW CONFIDENCE PLAN TO MAKE ONLY SMALL CHANGES TO THE INHERITED FORECAST WHICH WILL NOW CARRY CHC POP THROUGH THE PERIOD WITH TEMPS NEAR TO SLIGHTLY ABOVE CLIMO. && .AVIATION /11Z MONDAY THROUGH FRIDAY/... AS OF 06Z...PERSISTENCE FORECAST REGARDING AVIATION PURPOSES. BERMUDA HIGH PRESSURE WILL CONTINUE TO DOMINATE WX CONDITIONS THROUGH THE PERIOD WITH MOSTLY IFR CONDITIONS. SOME MODELS ARE GENERATING A LITTLE SEA BREEZE ACTIVITY ACROSS SOUTH CAROLINA BUT FEEL ANY ACTIVITY WILL BE TOO ISOLATED IN NATURE TO INCLUDE IN FORECAST. ADDED A LITTLE BR TO FLO FOR THE OVERNIGHT HOURS PER OBSERVATIONS THIS MORNING. EXTENDED OUTLOOK...PRE-DAWN MORNING FOG IS POSSIBLE EACH DAY THAT COULD RESULT IN MVFR/IFR CONDITIONS. UNSETTLED WEATHER THURSDAY NIGHT THROUGH SATURDAY WITH A SUBTROPICAL LOW. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM MONDAY...HIGH PRESSURE WILL SHIFT FARTHER OFF SHORE WHILE CONTINUING TO RIDGE BACK INTO THE COASTAL CAROLINAS. THEREFORE EXPECT A VERY LIGHT RETURN FLOW TO CONTINUE BASICALLY OUT OF THE SE-S LESS THAN 10 KTS. SEAS WILL RUN UNDER 3 FT MOST WATERS WITH A A VERY SLOW DECLINE THROUGH TODAY WITH SUCH LIGHT WINDS AND DIMINISHING LONGER PERIOD BACKSWELL FROM LOW MOVING OFF INTO THE DISTANT ATLANTIC WATERS. THE WNA SHOWS LONGER PERIOD SWELLS DROPPING OFF BY NOON TODAY WITH JUST SHORTER PERIOD WIND WAVES DOMINATING ESPECIALLY AS SEA BREEZE DEVELOPS THIS AFTERNOON. A PERSISTENT LIGHT ON SHORE RETURN FLOW WILL CAUSE A SLIGHT RISE IN SEAS THROUGH TONIGHT. OVERALL EXPECT BENIGN SEAS AROUND 2 TO 3 FT OR LESS WITH A SLIGHT SPIKE NEAR SHORE IN AFTERNOON SEA BREEZE. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...BERMUDA HIGH WILL MAINTAIN LIGHT EASTERLY FLOW TUE INTO WED. DURING THE SECOND HALF OF THE PERIOD THE HIGH WILL RETREAT NORTHEAST AS WEAK LOW PRESSURE EMERGES FROM THE BAHAMAS. WINDS WILL BACK TO NORTHEAST FOR WED AND WED NIGHT WITH A SLIGHT BUMP IS SPEED. CONFIDENCE WITH RESPECT TO THE AMOUNT OF STRENGTHENING THE LOW WILL UNDERGO AND ITS LOCATION IS RATHER LOW AND THUS FORECAST CONFIDENCE IS ALSO LOW. FOR NOW KEEPING WIND SPEEDS WED AND WED NIGHT CONFINED TO THE 15 TO 20 KT RANGE BUT HIGHER VALUES ARE POSSIBLE. SEAS 2 TO 3 FT TUE INTO WED SHOULD BUILD LATER WED AS NORTHEAST FLOW INCREASES AND COASTAL LOW STARTS TO BECOME A LITTLE MORE DEFINED. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3 AM MONDAY...MUCH OF THE FORECAST DEPENDS ON THE DETAILS OF THE HYBRID TROPICAL SYSTEM MEANDERING OFF THE SOUTHEAST COAST LATE THIS WEEK. WEAK STEERING FLOW ALOFT HAS SO FAR BEFUDDLED GUIDANCE AND NOT CONFIDENT CLARITY WILL DESCEND UPON THE FORECAST IN THE NEAR TERM. THAT SAID FEEL A FORECAST OF NORTHEAST FLOW IN THE 15 TO 20 KT RANGE IS A GOOD COMPROMISE AND IS IN LINE WITH PREVIOUS FORECASTS. SEAS WILL BUILD ON THE BACK OF EXTENDED NORTHEAST FLOW WITH SOME ZONES LIKELY TO EXCEED 6 FT IN PLACES ON THU AND REMAIN ABOVE 6 FT FRI. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...RGZ SHORT TERM...III LONG TERM...III AVIATION...SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
636 AM EDT MON MAY 4 2015 .SYNOPSIS... HIGH PRESSURE SYSTEM WILL CONTINUE TO DRIFT SLOWLY OFFSHORE EARLY TO MID-WEEK...PROVIDING SUNSHINE AND SEASONABLE MAY TEMPERATURES. A COASTAL LOW IS EXPECTED TO FORM IN THE BAHAMAS MID-WEEK...AND MEANDER ALONG THE SOUTHEAST COAST THROUGH THE END OF THE WEEK AND INTO NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM MONDAY...DRY AND SEASONABLE WEATHER WILL CONTINUE AS HIGH PRESSURE SLIPS FARTHER OFF SHORE WHILE CONTINUING TO RIDGE BACK INTO THE CAROLINAS. THIS WILL PROVIDE A LIGHT RETURN FLOW WITH A SLIGHT INCREASE IN MOISTURE. TEMPS DROPPING EARLY THIS MORNING WILL CREATE SOME VERY SHALLOW FOG BUT OVERALL COLUMN WILL REMAIN VERY DRY WITH ONLY LIMITED LOW LEVEL MOISTURE. A MID TO UPPER RIDGE TRIES TO BUILD OVERHEAD...BUT A SHORTWAVE RIDING DOWN FROM THE NW WILL DISRUPT THIS RIDGE AS IT MOVES SLOWLY OVER THE COASTAL CAROLINAS THROUGH THIS AFTERNOON WITH TROUGH BECOMING STRETCHED OUT ALONG THE COAST TONIGHT. AS THIS SHORTWAVE MOVES THROUGH IT WILL PRODUCE SOME PASSING MID LEVEL CLOUDS. THE LIGHT RETURN FLOW AROUND THE SFC HIGH WILL COMBINE WITH AFTERNOON SEA BREEZE TO GIVE IT A STRONG PUSH INLAND THROUGH THE AFTERNOON. CONVERGENCE ALONG THE SEA BREEZE AND THE WESTERN PERIPHERY OF HIGH PRESSURE WILL HELP BUILD SOME AFTERNOON CU. THE SHORTWAVE SHOULD ACT TO ENHANCE THE VERTICAL GROWTH A BIT...BUT A STRONG SUBSIDENCE INVERSION AROUND 8-9 K FT WILL CAP OFF THE CLOUDS AND LIMIT CHC OF SHWRS. THE HRRR TRIES TO GENERATE A FEW STRAY SHOWERS INLAND THIS AFTERNOON BUT BELIEVE THIS WILL JUST END UP BEING CLUSTERS OF CU. HUGE DIURNAL RANGES WILL CONTINUE WITH TEMPS STARTING OUT IN THE MID 50S THIS MORNING AND REACHING UP TO AROUND 80 EXCEPT SLIGHTLY COOLER AT THE BEACHES. CONTINUED ON SHORE FLOW AROUND HIGH WILL SUPPORT A SLOW RISE IN DEWPOINTS TONIGHT AFTER A DIURNAL DROP THIS AFTERNOON IN DEEPER MIXING. THIS WILL KEEP OVERNIGHT LOWS A FEW DEGREES HIGHER...BUT STILL DOWN TO 55 TO 60 MOST PLACES WITH IDEAL RADIATIONAL COOLING CONDITIONS UNDER CLEAR SKIES AND NEAR CALM WINDS. MAY SEE SOME PATCHY SHALLOW GROUND FOG AGAIN TONIGHT AS TEMPS DROP OUT BUT COLUMN WILL BE VERY DRY ABOVE THE SURFACE. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...BERMUDA HIGH ON TUESDAY WILL RETREAT WEDNESDAY AHEAD OF DISTURBANCE EMERGING FROM THE CARIBBEAN AND THE BAHAMAS. MID LEVEL RIDGING IN PLACE ABOVE THE BERMUDA HIGH TUE WILL MAINTAIN WARM AND DRY CONDITIONS ACROSS THE AREA WITH ONLY PATCHES OF SHALLOW AFTERNOON CU. ONSHORE FLOW WILL CONTINUE KEEPING TEMPS NEAR THE COAST AROUND CLIMO WHILE INLAND AREAS WARM UP A BIT. SECOND HALF OF THE PERIOD STARTS TO GET INTERESTING AS THE SYSTEM EMERGING FROM THE BAHAMAS WILL TRY AND COALESCE INTO A WELL DEFINED LOW. THE GOING WILL INITIALLY BE SLOW AND THE LACK OF STEERING FLOW ALOFT IS LIKELY TO KEEP THE SYSTEM SOUTH OF THE AREA THROUGH THE END OF THE PERIOD. STILL A LOT OF UNCERTAINTY REGARDING THIS SYSTEM AND WHILE IT MAY LEAD TO AN INCREASE IN CLOUD COVER...ESPECIALLY ALONG THE COAST WED NIGHT...DO NOT THINK IT WOULD DIRECTLY AFFECT THE REGION BEFORE THE END OF THE PERIOD. THUS WILL MAINTAIN THE DRY FORECAST WITH HIGHS AROUND CLIMO AND LOWS A BIT ABOVE CLIMO. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 3 AM MONDAY...LONG TERM PERIOD WILL BE DOMINATED BY THE LOW EVOLVING OFF THE SOUTHEAST COAST MID TO LATE WEEK. GUIDANCE CONTINUES TO STRUGGLE WITH THIS SYSTEM...MAINLY DUE TO THE LACK OF ANY REAL STEERING FLOW ALOFT. HOWEVER SOME SOLUTIONS SEEM HARD TO BUY. FOR INSTANCE THE LOW DEEPENING AND MOVING UP THE COAST SEEMS THE LEAST LIKELY OUTCOME GIVEN THE 5H RIDGING TO THE NORTH. DO THINK THE LOW COULD GRADUALLY STRENGTHEN THROUGH THE PERIOD. ALTHOUGH THE WATER TEMPS WITHIN THE GULF STREAM ARE AROUND 80 AND SHEAR SHOULD BE WEAK TO NONEXISTENT THERE ARE SEVERAL FACTORS THAT WOULD LIMIT STRENGTHENING. A LACK OF DIFFLUENCE ALOFT EARLY IN THE PERIOD AND THE LARGE SWATH OF SEA SURFACE TEMPS OUTSIDE THE GULF STREAM IN THE 60S BEING THE BIGGEST. SO WHILE SOME DEVELOPMENT OF THIS SYSTEM IS EXPECTED A FULL BLOWN TROPICAL SYSTEM SEEMS TO BE A LONG SHOT. INSTEAD THE SYSTEM WILL PROBABLY ACQUIRE SOME TROPICAL CHARACTERISTICS BUT REMAIN QUITE WEAK AS IT WANDERS OVER THE WATERS OFF THE SOUTHEAST COAST. WORTH NOTING A LOT OF THE GFS ENSEMBLES TAKE THE WEAK LOW INTO FL OR SOUTHERN GA...SOMETHING WHICH A FAIR NUMBER OF THE MEMBERS HAVE BEEN CONSISTENTLY SHOWING OVER THE LAST FEW DAYS. LOCALLY IMPACTS THROUGH THE PERIOD WILL BE NORTHEAST FLOW...WITH SOME ENHANCEMENT LATER IN THE WEEK AND AN INCREASE IN LOW LEVEL MOISTURE. THIS SHOULD BRING ABOUT AN INCREASE IN PRECIP CHANCES...ESPECIALLY ALONG THE COAST...AS THE WEEK WEARS ON. GIVEN THE LOW CONFIDENCE PLAN TO MAKE ONLY SMALL CHANGES TO THE INHERITED FORECAST WHICH WILL NOW CARRY CHC POP THROUGH THE PERIOD WITH TEMPS NEAR TO SLIGHTLY ABOVE CLIMO. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 06Z...NOT MUCH SYNOPTICALLY DIFFERENT FROM YESTERDAY...WITH HIGH PRESSURE OFFSHORE GIVING US SOUTHEAST FLOW. THERE IS FOG POTENTIAL AGAIN OVERNIGHT...MAINLY AFTER 08Z. CRE STANDS THE BEST CHANCE AGAIN...BUT COULD NOT RULE OUT INLAND FOG EITHER. DO NOT THINK WE WILL SEE THE LIFR CONDITIONS THAT WE EXPERIENCED LAST NIGHT. MONDAY...BECOMING VFR AT ALL LOCATIONS WITH CONTINUED SOUTHEAST FLOW...STRONGEST ALONG THE COAST. EXTENDED OUTLOOK...PRE-DAWN MORNING FOG IS POSSIBLE EACH DAY THAT COULD RESULT IN MVFR/IFR CONDITIONS. UNSETTLED WEATHER THURSDAY NIGHT THROUGH SATURDAY WITH A SUBTROPICAL LOW. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM MONDAY...HIGH PRESSURE WILL SHIFT FARTHER OFF SHORE WHILE CONTINUING TO RIDGE BACK INTO THE COASTAL CAROLINAS. THEREFORE EXPECT A VERY LIGHT RETURN FLOW TO CONTINUE BASICALLY OUT OF THE SE-S LESS THAN 10 KTS. SEAS WILL RUN UNDER 3 FT MOST WATERS WITH A A VERY SLOW DECLINE THROUGH TODAY WITH SUCH LIGHT WINDS AND DIMINISHING LONGER PERIOD BACKSWELL FROM LOW MOVING OFF INTO THE DISTANT ATLANTIC WATERS. THE WNA SHOWS LONGER PERIOD SWELLS DROPPING OFF BY NOON TODAY WITH JUST SHORTER PERIOD WIND WAVES DOMINATING ESPECIALLY AS SEA BREEZE DEVELOPS THIS AFTERNOON. A PERSISTENT LIGHT ON SHORE RETURN FLOW WILL CAUSE A SLIGHT RISE IN SEAS THROUGH TONIGHT. OVERALL EXPECT BENIGN SEAS AROUND 2 TO 3 FT OR LESS WITH A SLIGHT SPIKE NEAR SHORE IN AFTERNOON SEA BREEZE. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...BERMUDA HIGH WILL MAINTAIN LIGHT EASTERLY FLOW TUE INTO WED. DURING THE SECOND HALF OF THE PERIOD THE HIGH WILL RETREAT NORTHEAST AS WEAK LOW PRESSURE EMERGES FROM THE BAHAMAS. WINDS WILL BACK TO NORTHEAST FOR WED AND WED NIGHT WITH A SLIGHT BUMP IS SPEED. CONFIDENCE WITH RESPECT TO THE AMOUNT OF STRENGTHENING THE LOW WILL UNDERGO AND ITS LOCATION IS RATHER LOW AND THUS FORECAST CONFIDENCE IS ALSO LOW. FOR NOW KEEPING WIND SPEEDS WED AND WED NIGHT CONFINED TO THE 15 TO 20 KT RANGE BUT HIGHER VALUES ARE POSSIBLE. SEAS 2 TO 3 FT TUE INTO WED SHOULD BUILD LATER WED AS NORTHEAST FLOW INCREASES AND COASTAL LOW STARTS TO BECOME A LITTLE MORE DEFINED. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3 AM MONDAY...MUCH OF THE FORECAST DEPENDS ON THE DETAILS OF THE HYBRID TROPICAL SYSTEM MEANDERING OFF THE SOUTHEAST COAST LATE THIS WEEK. WEAK STEERING FLOW ALOFT HAS SO FAR BEFUDDLED GUIDANCE AND NOT CONFIDENT CLARITY WILL DESCEND UPON THE FORECAST IN THE NEAR TERM. THAT SAID FEEL A FORECAST OF NORTHEAST FLOW IN THE 15 TO 20 KT RANGE IS A GOOD COMPROMISE AND IS IN LINE WITH PREVIOUS FORECASTS. SEAS WILL BUILD ON THE BACK OF EXTENDED NORTHEAST FLOW WITH SOME ZONES LIKELY TO EXCEED 6 FT IN PLACES ON THU AND REMAIN ABOVE 6 FT FRI. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...RGZ SHORT TERM...III LONG TERM...III AVIATION...RGZ/DL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1034 AM CDT MON MAY 4 2015 .UPDATE... ISSUED AT 1030 AM CDT MON MAY 4 2015 CURRENT FORECAST LOOKS IN GOOD SHAPE. ONLY CHANGES WERE TO TREND POPS LOWER OVER THE SOUTHWEST TODAY. A FEW SHOWERS EARLIER HAVE DISSIPATED. THUS DRY FOR THE REMAINDER OF THE MORNING. WILL KEEP A SLIGHT CHANCE OF AFTERNOON SHOWERS WITH WEAK INSTABILITY. LATEST NAM AND RAP INDICATE ANY SHOWER ACTIVITY WILL DISSIPATE BY EVENING...THUS DROPPED THE SLIGHT CHANCE OF EVENING POPS. UPDATE ISSUED AT 851 AM CDT MON MAY 4 2015 QUICK UPDATE TO END THE FROST ADVISORY. TEMPERATURES QUICKLY RISING THIS MORNING. MORNING LOWS IN THE UPPER 20S TO LOWER 30S ARE MOSTLY IN THE 40S ALREADY. OTHERWISE ONLY SOME MINOR ADJUSTMENTS TO SKY COVER AND POPULATED LATEST SENSIBLE WEATHER ELEMENTS. UPDATE ISSUED AT 646 AM CDT MON MAY 4 2015 MID/HIGH CLOUDS CONTINUE ALONG THE ND/SD BORDER THIS MORNING WITH CLEAR SKIES TO THE NORTH. BOWMAN RADAR SHOWS A COUPLE OF SHOWERS IN WESTERN BOWMAN COUNTY. CURRENT FORECAST LOOKS GOOD. ALSO UPDATED AND TRIMMED THE THUNDERSTORM CHANCES FOR THURSDAY AS THE CAPE SHUNTS OFF TO THE EAST LEAVING THE WEST AND CENTRAL MAINLY STABLE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 258 AM CDT MON MAY 4 2015 FOR THE NEAR TERM...MAIN HIGHLIGHT IS THE FROST ADVISORY THROUGH 9AM CDT MONDAY. CURRENT TEMPERATURES ARE MOSTLY IN THE LOW TO MID 30S. ISOLATED SPOTS OF UPPER 20S AROUND HAZEN TO GLEN ULLIN. OVERALL THE FROST ADVISORY IS VERIFYING AND WILL CONTINUE AS SCHEDULED. IN THE SHORT TERM PERIOD...THE UPPER AIR PATTERN IS UNDERGOING A CHANGE...FROM WESTERLY TO SOUTHERLY. THE LATEST WATER VAPOR IMAGERY LOOP SHOWS PLENTY OF MOISTURE LOCATED WITHIN THE SOUTHERN JET BRANCH AS AN UPPER LOW OVER THE FAR SOUTHWEST CONUS BEGINS TO SLOWLY ADVANCE NORTHEAST. CURRENTLY...STILL ENOUGH OF A WESTERLY UPPER FLOW ACROSS CENTRAL AND NORTHERN NORTH DAKOTA TO SHUNT ANY SIGNIFICANT MOISTURE OFF TO THE EAST. HOWEVER...TWO SHORTWAVES EARLY THIS MORNING ARE LEADING THE CHANGE TO A MORE SOUTHERLY UPPER FLOW INTO NORTH DAKOTA. THE SHORTWAVES ARE LOCATED ACROSS WYOMING...ONE IN NORTHWEST AND THE SECOND SHORTWAVE IN THE NORTHEAST. LIGHT RAIN PER SURFACE OBSERVATIONS AND REGIONAL RADAR WAS OCCURRING OVER NORTHEAST WYOMING AND SOUTHWEST SOUTH DAKOTA. FOR TODAY...WITH THE EXCEPTION OF FAR SOUTHWEST NORTH DAKOTA...A BUILDING 700MB RIDGE AXIS WILL KEEP THE FORECAST DRY UNDER A MOSTLY SUNNY SKY/LIGHT WINDS...WITH HIGHS IN THE UPPER 60S TO AROUND 70. THE THREAT FOR SHOWERS WILL BE CONFINED TO THE FAR SOUTHWEST TODAY ASSOCIATED WITH THE ABOVE MENTIONED SHORTWAVES...BUT DIMINISH THROUGH THE AFTERNOON AS VERTICAL MOTION GETS SQUASHED AS THE SHORTWAVES APPROACH THE MID LEVEL RIDGE AXIS. SOUTHEAST WINDS WILL BE STRONGEST IN THE FAR SOUTHWEST BETWEEN 20 AND 35 MPH. WITH THE ADVECTION OF MOISTURE AND A CHANCE OF SHOWERS INTO THE FAR SOUTHWEST TODAY...THE STRONGEST WINDS IN THE FAR SOUTHWEST WILL COINCIDE WITH ELEVATED MINIMUM RELATIVE HUMIDITIES OF AROUND 35 PERCENT. THE WEAKEST WINDS...AROUND 10 MPH...WILL COINCIDE WITH MINIMUM RELATIVE HUMIDITIES OF 20 PERCENT. THUS NO FIRE WEATHER HEADLINES TODAY. A SOUTHERLY FLOW THROUGH THE LOWER AND MIDDLE LEVELS WILL BECOME ESTABLISHED MONDAY NIGHT AS THE 700MB RIDGE AXIS SHIFTS INTO SOUTHERN MANITOBA AND MINNESOTA. HOWEVER NO SIGNIFICANT SHORTWAVES/PRECIPITATION FORECAST THROUGH 12Z TUESDAY. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 258 AM CDT MON MAY 4 2015 GFS/ECMWF LOOK IN GOOD AGREEMENT AND HAVE REASONABLE RUN TO RUN CONSISTENCY AS WELL. MODELS MOVE AN H500 LOW OVER CENTRAL CANADA EAST AS A LARGE H500 TROUGH MOVES ONSHORE ACROSS THE WESTERN US BEGINNING TUESDAY. AS THIS HAPPENS SOME H500 ENERGY KICKS OUT AHEAD OF THIS TROUGH AND MOVES NORTH AND EAST INTO THE NORTHERN PLAINS BRINGING A GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS WEST AND CENTRAL NORTH DAKOTA TUESDAY NIGHT THROUGH THURSDAY. SHOWERS AND SCATTERED THUNDERSTORMS REMAIN IN THE FORECAST THROUGH FRIDAY. THE WEEKEND WILL SEE A COOLDOWN AS THE H500 TROUGH MOVES OVER THE REGION AND AN H850 THERMAL TROUGH SETTLES IN OVER THE REGION SAT/SUNDAY PERIOD. REMOVED THE MENTION OF THUNDERSTORMS AFTER FRIDAY DO TO THE LACK OF INSTABILITY. GFS TEMPERATURES MAY BE COOL ENOUGH FOR A RAIN/SNOW MIX ON SAT NIGHT BUT DO NOT WANT TO MAKE TOO MUCH OF THIS AS THE ECMWF IS WARMER. HIGHS WILL BE IN THE 60S TO LOWER 70S TUESDAY AND WEDNESDAY...THEN 50S AND 60S THURSDAY AND FRIDAY AND IN THE 50S SATURDAY AND SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 851 AM CDT MON MAY 4 2015 VFR CIGS/VSBYS THROUGH 12Z TUESDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TWH SHORT TERM...KS LONG TERM...WAA AVIATION...TWH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
632 AM CDT MON MAY 4 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 400 AM CDT MON MAY 4 2015 CHALLENGING FORECAST LOOKS TO BEGIN WITH CHALLENGING SHORT TERM. OVERNIGHT...HAVE SEEN THE STRONG SURFACE FRONTAL BOUNDARY SETTLE INTO FAR SOUTHERN PORTIONS OF THE REGION...AS MUCH DRIER AIR HAS INVADED FROM THE NORTH BEHIND THE BOUNDARY. SEVERAL CONTRADICTING FACTORS TO THE SHORT TERM PRECIPITATION FORECAST. FIRST...VERY FEW SOLUTIONS HAVE AMPLE HANDLE ON THE DRY AIR INTRUSION AT LOWEST LEVELS...WITH DEWPOINTS INTO THE UPPER 20S AND 30S OVER ALL BUT THE EXTREME SOUTHEAST CWA. SECOND...THE DEGREE OF ELEVATED INSTABILITY ACROSS THE FAR SOUTHERN CWA IS LACKING IN SHORT TERM HIGH RESOLUTION MODELS...WHICH IS EVIDENT GIVEN RECENT UPTAKE IN SCATTERED BANDED CONVECTION FROM THE LOWER MISSOURI VALLEY EASTWARD ACROSS NORTHWEST IOWA FORCED IN BROAD JET ENTRANCE REGION. THIRD...DEALING WITH TYPICAL BATTLE OF LOWER VERSUS HIGHER RESOLUTION MODELS. LARGE SCALE SYNOPTIC TREND IS FOR LOWER LEVEL BAROCLINIC ZONE TO SETTLE FURTHER SOUTHWARD OVER LAST COUPLE OF MODEL RUNS. HOWEVER...SOME QUESTION AS TO HOW MUCH FURTHER THE MID LEVEL BOUNDARY WILL SETTLE GIVEN THE PROXIMITY OF UPPER LEVEL JET ENTRANCE REGION PASSING ACROSS THE AREA TODAY. HIGHER RESOLUTION MODELS GENERALLY MUCH MORE AGGRESSIVE WITH NORTHWARD SPREAD OF PRECIPITATION. HOWEVER...SHOULD MAKE NOTE THAT TREND IN RAP HAS BEEN TO ALLOW LESS AND LESS THREAT TO SOUTHERN CWA THROUGH THE DAY. EARLY ON THIS MORNING...SHOULD SEE A GRADUAL DECREASE IN THE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE FAR SOUTH EARLY THIS MORNING AS THE WAVE CONTINUES TO SHEAR AWAY. WILL SEE RIDGING BEGIN TO REESTABLISH PRESENCE...BUT BATTLE A SMALL WAVE WANDERING FROM KANSAS TOWARD EASTERN NEBRASKA LATER IN THE DAY. CONVECTION SHOULD BREAK OUT CLOSER TO THIS FEATURE AND THE DEEPER SYNOPTIC BOUNDARY...EXPANDING AND TRENDING TOWARD A MORE EASTWARD MOTION WITH TIME ALONG BAROCLINIC ZONE EXPANDING TOWARD THE SIOUX CITY AREA LATE DAY. GRADUALLY...THIS WAVE PULLS EASTWARD AND MAY SEE MOST EXPANSIVE COVERAGE BRUSH THROUGH THE SOUTHERN CWA DURING THE EVENING HOURS...THEN PROGRESS TOWARD A MORE SCATTERED COVERAGE AS MID LEVEL WAVE AND ISENTROPIC ASCENT PUSHES NORTHWARD WITH DEEPENING SOUTHERLY FLOW. OVERALL...WILL BE LOOKING FOR THUNDER COVERAGE TO BE SMALL FRACTION OF THE OVERALL PRECIPITATION...WITH BEST THREAT THROUGH THE SOUTHEAST HALF OF THE CWA OVERNIGHT. NO SEVERE STORMS ARE EXPECTED WITH MINIMAL ELEVATED INSTABILITY AND GENERALLY WEAK MID LEVEL FLOW. TEMPWISE...WILL SET UP FOR FAIRLY DECENT EASTERLY MIXING WITH DRY AIR...DESPITE A DECENT AMOUNT OF CLOUDINESS MOST LOCATIONS THROUGH THE DAY. HIGHS SHOULD BE MAINLY UPPER 60S TO LOWER 70S...ON THE WARM SIDE OF MIXING POTENTIAL DUE TO THE DRY AIR. INCREASING MOISTURE TONIGHT FROM SOUTH TO NORTH WILL DEFINE LOWS UNDER THICKER CLOUDS...MID 40S NORTH TO LOWER TO MID 50S SOUTH. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 400 AM CDT MON MAY 4 2015 A RATHER MESSY MEDIUM AND EXTENDED FORECAST IS IN STORE FOR THE REGION THIS WEEK AND INTO NEXT WEEKEND. THE LONG WAVE PATTERN WILL BE DOMINATED BY LONG WAVE RIDGING ACROSS THE CONUS THIS WEEK...WITH SEVERAL TROUGHS LIFTING THROUGH THE PLAINS. THE MAIN WEATHER FEATURE THROUGH WEDNESDAY/THURSDAY WILL BE A BROAD UPPER LOW CURRENTLY OVER THE SOUTHWESTERN UNITED STATES THAT IS EXPECTED TO SLIDE ALONG THE WESTERN PERIPHERY OF THE RIDGE. BY TUESDAY...THIS TROUGH WILL BEGIN TO NUDGE THE LOW-LVL BAROCLINIC ZONE NORTHWARD...WITH BROAD ISENTROPIC LIFT BRINING A CHANCE FOR SHOWERS TO THE AREA ON TUESDAY. THE PRIMARY CONCERN WILL BE JUST HOW WIDESPREAD THIS ACTIVITY WILL BE...AS SHORTWAVE ENERGY MOVING THROUGH LATER TONIGHT SLIDES EAST OF THE AREA ON TUESDAY...ONLY TO BE REPLACED BY SHORTWAVE RIDGING. AND ADDITIONAL FACTOR IS THE DEGREE OF DRY AIR REMAINING IN THE SUB-700 MB LAYER. WITH THE LIFT BROAD IN NATURE...AND MOISTURE LIMITED TO A DEGREE...QPF THROUGH TUESDAY NIGHT SHOULD BE FAIRLY LOW. THEN A STRONGER PORTION OF THE AFOREMENTIONED UPPER TROUGH WILL BEGIN TO LIFT INTO THE PLAINS ON WEDNESDAY. MODELS ALL IN GOOD AGREEMENT THAT REMNANT CONVECTION FROM TUESDAY NIGHT ON THE WESTERN PLAINS WILL LIFT INTO THE LOCAL AREA DURING THE DAY ON WEDNESDAY WITH BROAD AND STRONG ISENTROPIC LIFT ASSISTING IN THE DEVELOPMENT OF ADDITIONAL SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY THROUGH THE DAY. MOISTURE TRANSPORT RATHER IMPRESSIVE...BRINGING PWAT VALUES AROUND 1.5 INCHES INTO THE AREA. HOWEVER...A DISTINCT LACK OF INSTABILITY IS ASSOCIATED WITH THIS PRECIPITATION FOR MUCH OF WEDNESDAY...AND THIS SHOULD KEEP QPF DOWN. DEPENDING ON THE SPEED OF PRECIPITATION WEDNESDAY MORNING...WILL NEED TO WATCH FOR THE POTENTIAL OF CLOUDS SCATTERING LATER IN THE AFTERNOON. A SECONDARY ROUND OF CONVECTION WILL LIKELY DEVELOP ALONG INVERTED TROUGH OR DRYLINE ACROSS WESTERN NEBRASKA/KANSAS LATE WEDNESDAY AFTERNOON. ONCE FORMED...IT WILL LIFT NORTHEAST WITH THE SHORTWAVE WEDNESDAY NIGHT. MUCAPE VALUES COULD CLIMB AS HIGH AS 500- 1000 J/KG WEDNESDAY EVENING AND SHEAR WILL BE ON THE INCREASE...MAINLY SOUTH AND WEST OF THE JAMES RIVER. THAT SAID...FEEL THE GENERAL RISK OF SVR STORMS IS LOW...BUT COULD SEE MARGINAL OUTLOOK SLIDE A BIT FURTHER NORTH. I WOULD ANTICIPATE QUITE A BIT OF THUNDER AS THIS ACTIVITY LIFTS THROUGH THE AREA INTO THURSDAY MORNING. FEEL MOST OF THURSDAY WILL BE DRY...AS UPPER FORCING LIFTS NORTHEAST. THE UPPER TROUGH COULD LEAVE AN ELONGATED BOUNDARY ACROSS THE SOUTHERN ZONES BY THURSDAY AFTERNOON. MODELS STILL VARY SIGNIFICANTLY WITH THIS FRONT...BUT A DECENT BUILDUP OF INSTABILITY ALONG AND SOUTH OF IT COULD BE TAPPED INTO SHOULD A WEAK WAVE LIFT NORTHWARD IN THE SWLY FLOW ALOFT. SHEAR CONTINUES TO BE MARGINAL...BUT COULD SUPPORT A SEVERE STORM. FRIDAY MAY BE THE DRIEST DAY OF THE EXTENDED...AS MODELS ARE IN REASONABLE AGREEMENT FORMING A DEEP TROUGH OVER THE WESTERN THIRD OF THE CONUS. BEYOND FRIDAY...BEGINNING TO LOOK RATHER WET ACROSS MANY AREAS AS THIS UPPER TROUGH BEGINS TO LIFT INTO THE PLAINS AND EVENTUALLY GREAT LAKES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 631 AM CDT MON MAY 4 2015 MAIN CONCERN FOR THIS PERIOD IS POTENTIAL AND TIMING DEVELOPMENT OF ELEVATED CONVECTION FOR KFSD AND KSUX. STRONG WAVE WILL MOVE FROM KANSAS TO EASTERN NEBRASKA BY LATE AFTERNOON. ELEVATED CONVECTION WILL SPREAD NORTH AND EAST TODAY...EXPECTED TO SPREAD LATE AFTERNOON INTO SIOUX CITY. OVERALL ELEVATED INSTABILITY IS FAIRLY WEAK...SO STUCK WITH MENTION OF SHOWERS WITH PEAK MENTION BETWEEN 00Z AND 04Z. THERE WILL STILL BE A THREAT FOR ADDITIONAL SHOWERS AND PERHAPS A RUMBLE OF THUNDER EVEN AFTER 04Z FOR KSUX... BUT SHOULD DIMINISH TO A MORE SCATTERED THREAT LATER INTO THE NIGHT. FOR KHON...THREAT APPEARS MINIMAL LATE IN PERIOD AND HAVE NOT INCLUDED IN TAF. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHAPMAN LONG TERM...DUX AVIATION...CHAPMAN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1003 AM MDT MON MAY 4 2015 .UPDATE... ISSUED AT 1000 AM MDT MON MAY 4 2015 A CHECK OF THE I-80 WEBCAMS INDICATED THAT THE DENSE FOG WAS LIFTING BETWEEN CHEYENNE AND LARAMIE...ESPECIALLY AT THE SUMMIT. THE DENSE FOG ADVISORY WAS ALLOWED TO EXPIRE AT 10 AM...WITH AREAS OF FOG LINGERING THRU THE LATE MORNING. UPDATE ISSUED AT 459 AM MDT MON MAY 4 2015 WEBCAMS ALONG INTERSTATE 80 HAVE SHOWN VIS REALLY COMING DOWN FROM THE SUMMIT TO JUST EAST OF BUFORD. MOIST SOUTHEAST WINDS WILL CONTINUE THROUGH THE MORNING AND HRRR SHOWS LIFR CONDITIONS CONTINUING IN THE SOUTHERN LARAMIE RANGE AND TO THE EAST OF THE ALBANY-LARAMIE COUNTY LINE THROUGH 16Z. THUS...WITH THE EXPECTATION THAT THE FOG WILL BE QUITE PERSISTENT THROUGH MID MORNING...DECIDED TO ISSUE A DENSE FOG ADVISORY FOR THE SOUTHERN LARAMIE RANGE AND ADJACENT FOOTHILLS THRU 16Z. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 230 AM MDT MON MAY 4 2015 THE GFS AND NAM BOTH PROG A WEAK MID LEVEL VORT MAX MOVING INTO NORTHEAST COLORADO AND THE SOUTHERN NEBRASKA PANHANDLE THROUGH MID MORNING. RADAR IMAGERY SHOWS SOME WEAK ECHOES ACROSS PORTIONS OF NORTHERN COLORADO (GENERALLY MOVING NORTHWARD)...BUT NO LIGHTNING OR STRONGER CONVECTIVE CELLS. WHILE THESE SHOWERS COULD MOVE INTO AREAS ALONG INTERSTATE 80 THROUGH MID MORNING...ANY ACCUMULATIONS WILL BE LIGHT. WITH SFC HIGH PRESSURE ACROSS THE DAKOTAS...LOW LEVELWINDS OVER THE PLAINS ARE TURNING TO THE EAST AND SOUTHEAST. THE HRRR HAS LIFR CONDITIONS DEVELOPING AFTER 10-11Z ALONG THE CHEYENNE RIDGE FROM THE INTERSTATE 80 SUMMIT TO CHEYENNE. WITH GOOD LOW LEVEL UPSLOPE...THESE LOWER CIGS AND VIS PERSIST THROUGH 18Z. THUS...KEPT THE MENTION OF FOG GOING THROUGH THE ENTIRE MORNING. TEMPS WILL BE AROUND 15 DEGREES COOLER TODAY FOR AREAS ALONG AND EAST OF THE LARAMIE RANGE IN THE POST FRONTAL AIR MASS. THE AIR MASS IS RATHER STABLE WITH LI VALUES GENERALLY ABOVE 0C...THUS AFTN CONVECTION WILL BE QUITE LIMITED. A BETTER CHANCE OF TSTMS WILL EXIST TO THE WEST OF THE LARAMIE RANGE. WHILE AN ISOLATED HIGHER RAINFALL AMOUNT IS POSSIBLE THROUGH MIDDAY TUESDAY...THE MODELS REALLY DO NOT SHOW MUCH QPF WITH THE INCREASE STABILITY. ON TUESDAY LOW CLOUDS WILL BE MUCH MORE WIDESPREAD AND PERSISTENT ACROSS THE PLAINS THROUGH THE MORNING OR EVEN EARLY AFTN WITH THE POTENTIAL FOR FOG ONCE AGAIN MAINLY ALONG THE CHEYENNE RIDGE. SUBTROPICAL MID LEVEL LOW OVER ARIZONA TODAY WILL PROGRESS NORTHEASTWARD INTO COLORADO ON TUESDAY. COOLING ALOFT AHEAD OF THIS FEATURE ALONG WITH INCREASING PW VALUES (UP TO 1.0 INCHES ACROSS THE PANHANDLE BY TUESDAY AFTN)...WILL PROMOTE A MORE WIDESPREAD COVERAGE OF SHOWERS AND TSTMS. HAVE THE HIGHEST POPS ON TUESDAY AFTN AND EVENING OVER THE PANHANDLE WHERE THE MODELS HAVE BEEN CONSISTENTLY SHOWING THE BEST FORCING. SPC DOES HAVE THE SOUTHERN PANHANDLE IN A MARGINAL RISK FOR SEVERE STORMS ON TUESDAY...HOWEVER WITH RATHER WEAK INSTABILITY AND SHEAR...ONLY SMALL HAIL WOULD BE A CONCERN. THE UPPER LEVEL WAVE WILL MOVE INTO WESTERN SOUTH DAKOTA BY WED WITH SFC WINDS BECOMING NORTH TO NORTHWEST OVER MUCH OF THE CWA BY THE AFTN. KEPT THE 40-50 PERCENT POPS GOING DURING THE AFTN AS RATHER HIGH PW VALUES (0.75-1.0 INCHES) ARE SHOWN ACROSS THE PLAINS ALONG WITH WEAK INSTABILITY. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 230 AM MDT MON MAY 4 2015 ACTIVE WEATHER IN THE LONG TERM CONTINUES WITH DAILY RAIN/THUNDER CHANCES ALSO THE POSSIBILITY OF A WINTER WEATHER EVENT FOR NEXT WEEKEND. FOR WEDNESDAY NIGHT...FIRST LOW LOOKS TO TRACK OFF TO THE NORTHEAST INTO CENTRAL SOUTH DAKOTA AND WE SHOULD BE SEEING SHOWERS AND THUNDERSTORMS COMING TO AN END BY LATE EVENING. ANOTHER COLD FRONT LOOKS TO MOVE INTO THE AREA THURSDAY MORNING WITH ANOTHER ROUND OF RAIN SHOWERS DEVELOPING ACROSS THE AREA THURSDAY AFTERNOON...PERSISTING INTO FRIDAY. REMARKABLY STRONG AGREEMENT BETWEEN THE GFS AND ECMWF ON THE MOVEMENT OF THE SECOND LOW THROUGH THE ROCKIES THROUGH THE WEEKEND. BOTH BRING THE LOW THROUGH SOUTHERN NEVADA FRIDAY...WITH IT EJECTING NORTHEAST INTO NORTHERN COLORADO SATURDAY NIGHT. BOTH SHOW -4 TO POSSIBLY -6C TEMPERATURES AT 700MB SATURDAY NIGHT INTO SUNDAY...WHICH WOULD TURN RAIN OVER TO SNOW FOR MANY LOCATIONS ABOVE 6000 FEET. NEED TO BE WATCHING FOR WINTER HEADLINES FOR POSSIBLE HEAVY SNOW THIS WEEKEND. WE WILL CERTAINLY BE MONITORING THIS LOW AS IT DRAWS CLOSER. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 459 AM MDT MON MAY 4 2015 IMPACTS TODAY WILL BE LOW CONDITIONS AROUND KCYS THIS MORNING IN UPSLOPE FOG/STRATUS...THEN SHOWERS AND THUNDERSTORMS MAINLY WEST OF THE LARAMIE RANGE TODAY. HRRR USED FOR KCYS AND SHOWS IFR/LIFR FOG/STRATUS DEVELOPING SHORTLY AFTER 12Z. ALREADY SEEING DENSE FOG JUST WEST OF KCYS. LOOKS TO STAY IFR/LIFR THROUGH 18Z BEFORE LIFTING. MORE WIDESPREAD LOW CONDITIONS EXPECTED TONIGHT. && .FIRE WEATHER... ISSUED AT 230 AM MDT MON MAY 4 2015 A COOL AND WET WEATHER PATTERN WILL MEAN MINIMAL FIRE WEATHER CONCERNS THROUGH THE WEEK. AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS CAN BE EXPECTED EACH DAY...WITH GOOD CHANCES FOR MEASURABLE PRECIPITATION AND WETTING RAINS. MINIMUM RELATIVE HUMIDITY VALUES SHOULD BE WELL ABOVE CRITICAL THRESHOLDS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...MJ SHORT TERM...ZF LONG TERM...GCC AVIATION...GCC FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
507 AM MDT MON MAY 4 2015 .UPDATE... ISSUED AT 459 AM MDT MON MAY 4 2015 WEBCAMS ALONG INTERSTATE 80 HAVE SHOWN VIS REALLY COMING DOWN FROM THE SUMMIT TO JUST EAST OF BUFORD. MOIST SOUTHEAST WINDS WILL CONTINUE THROUGH THE MORNING AND HRRR SHOWS LIFR CONDITIONS CONTINUING IN THE SOUTHERN LARAMIE RANGE AND TO THE EAST OF THE ALBANY-LARAMIE COUNTY LINE THROUGH 16Z. THUS...WITH THE EXPECTATION THAT THE FOG WILL BE QUITE PERSISTENT THROUGH MID MORNING...DECIDED TO ISSUE A DENSE FOG ADVISORY FOR THE SOUTHERN LARAMIE RANGE AND ADJACENT FOOTHILLS THRU 16Z. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 230 AM MDT MON MAY 4 2015 THE GFS AND NAM BOTH PROG A WEAK MIDLVL VORT MAX MOVING INTO NORTHEAST COLORADO AND THE SOUTHERN NEBRASKA PANHANDLE THROUGH MID MORNING. RADAR IMAGERY SHOWS SOME WEAK ECHOES ACROSS PORTIONS OF NORTHERN COLORADO (GENERALLY MOVING NORTHWARD)...BUT NO LIGHTNING OR STRONGER CONVECTIVE CELLS. WHILE THESE SHOWERS COULD MOVE INTO AREAS ALONG INTERSTATE 80 THROUGH MID MORNING...ANY ACCUMULATIONS WILL BE LIGHT. WITH SFC HIGH PRESSURE ACROSS THE DAKOTAS...LLVL WINDS OVER THE PLAINS ARE TURNING TO THE EAST AND SOUTHEAST. THE HRRR HAS LIFR CONDITIONS DEVELOPING AFTER 10-11Z ALONG THE CHEYENNE RIDGE FROM THE INTERSTATE 80 SUMMIT TO CHEYENNE. WITH GOOD LLVL UPSLOPE...THESE LOWER CIGS AND VIS PERSIST THROUGH 18Z. THUS...KEPT THE MENTION OF FOG GOING THROUGH THE ENTIRE MORNING. TEMPS WILL BE AROUND 15 DEGREES COOLER TODAY FOR AREAS ALONG AND EAST OF THE LARAMIE RANGE IN THE POST FRONTAL AIRMASS. THE AIRMASS IS RATHER STABLE WITH LI VALUES GENERALLY ABOVE 0C...THUS AFTN CONVECTION WILL BE QUITE LIMITED. A BETTER CHANCE OF TSTMS WILL EXIST TO THE WEST OF THE LARAMIE RANGE. WHILE AN ISOLATED HIGHER RAINFALL AMOUNT IS POSSIBLE THROUGH MIDDAY TUES...THE MODELS REALLY DO NOT SHOW MUCH QPF WITH THE INCREASE STABILITY. ON TUES LOW CLOUDS WILL BE MUCH MORE WIDESPREAD AND PERSISTENT ACROSS THE PLAINS THROUGH THE MORNING OR EVEN EARLY AFTN WITH THE POTENTIAL FOR FOG ONCE AGAIN MAINLY ALONG THE CHEYENNE RIDGE. SUBTROPICAL MIDLVL LOW OVER ARIZONA TODAY WILL PROGRESS NORTHEASTWARD INTO COLORADO ON TUES. COOLING ALOFT AHEAD OF THIS FEATURE ALONG WITH INCREASING PW VALUES (UP TO 1.0 INCHES ACROSS THE PANHANDLE BY TUES AFTN)...WILL PROMOTE A MORE WIDESPREAD COVERAGE OF SHOWERS AND TSTMS. HAVE THE HIGHEST POPS ON TUES AFTN AND EVENING OVER THE PANHANDLE WHERE THE MODELS HAVE BEEN CONSISTENTLY SHOWING THE BEST FORCING. SPC DOES HAVE THE SOUTHERN PANHANDLE IN A MARGINAL RISK FOR SVR STORMS ON TUES...HOWEVER WITH RATHER WEAK INSTABILITY AND SHEAR...ONLY SMALL HAIL WOULD BE A CONCERN. THE UPPER LEVEL WAVE WILL MOVE INTO WESTERN SOUTH DAKOTA BY WED WITH SFC WINDS BECOMING NORTH TO NORTHWEST OVER MUCH OF THE CWA BY THE AFTN. KEPT THE 40-50 PERCENT POPS GOING DURING THE AFTN AS RATHER HIGH PW VALUES (0.75-1.0 INCHES) ARE SHOWN ACROSS THE PLAINS ALONG WITH WEAK INSTABILITY. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 230 AM MDT MON MAY 4 2015 ACTIVE WEATHER IN THE LONG TERM CONTINUES WITH DAILY RAIN/THUNDER CHANCES ALSO THE POSSIBILITY OF A WINTER WEATHER EVENT FOR NEXT WEEKEND. FOR WEDNESDAY NIGHT...FIRST LOW LOOKS TO TRACK OFF TO THE NORTHEAST INTO CENTRAL SOUTH DAKOTA AND WE SHOULD BE SEEING SHOWERS AND THUNDERSTORMS COMING TO AN END BY LATE EVENING. ANOTHER COLD FRONT LOOKS TO MOVE INTO THE AREA THURSDAY MORNING WITH ANOTHER ROUND OF RAIN SHOWERS DEVELOPING ACROSS THE AREA THURSDAY AFTERNOON...PERSISTING INTO FRIDAY. REMARKABLY STRONG AGREEMENT BETWEEN THE GFS AND ECMWF ON THE MOVEMENT OF THE SECOND LOW THROUGH THE ROCKIES THROUGH THE WEEKEND. BOTH BRING THE LOW THROUGH SOUTHERN NEVADA FRIDAY...WITH IT EJECTING NORTHEAST INTO NORTHERN COLORADO SATURDAY NIGHT. BOTH SHOW -4 TO POSSIBLY -6C TEMPERATURES AT 700MB SATURDAY NIGHT INTO SUNDAY...WHICH WOULD TURN RAIN OVER TO SNOW FOR MANY LOCATIONS ABOVE 6000 FEET. NEED TO BE WATCHING FOR WINTER HEADLINES FOR POSSIBLE HEAVY SNOW THIS WEEKEND. WE WILL CERTAINLY BE MONITORING THIS LOW AS IT DRAWS CLOSER. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 459 AM MDT MON MAY 4 2015 IMPACTS TODAY WILL BE LOW CONDITIONS AROUND KCYS THIS MORNING IN UPSLOPE FOG/STRATUS...THEN SHOWERS AND THUNDERSTORMS MAINLY WEST OF THE LARAMIE RANGE TODAY. HRRR USED FOR KCYS AND SHOWS IFR/LIFR FOG/STRATUS DEVELOPING SHORTLY AFTER 12Z. ALREADY SEEING DENSE FOG JUST WEST OF KCYS. LOOKS TO STAY IFR/LIFR THROUGH 18Z BEFORE LIFTING. MORE WIDESPREAD LOW CONDITIONS EXPECTED TONIGHT. && .FIRE WEATHER... ISSUED AT 230 AM MDT MON MAY 4 2015 A COOL AND WET WEATHER PATTERN WILL MEAN MINIMAL FIRE WEATHER CONCERNS THROUGH THE WEEK. AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS CAN BE EXPECTED EACH DAY...WITH GOOD CHANCES FOR MEASURABLE PRECIPITATION AND WETTING RAINS. MINIMUM RELATIVE HUMIDITY VALUES SHOULD BE WELL ABOVE CRITICAL THRESHOLDS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...DENSE FOG ADVISORY UNTIL 10 AM MDT THIS MORNING FOR WYZ116-117. NE...NONE. && $$ UPDATE...ZF SHORT TERM...ZF LONG TERM...GCC AVIATION...GCC FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS ALBANY NY
145 PM EDT MON MAY 4 2015 .SYNOPSIS... PLENTY OF SUNSHINE AND A WARM SOUTHWESTERLY FLOW WILL ALLOW FOR ABOVE NORMAL TEMPERATURES TODAY. AN APPROACHING COLD FRONT WILL BRING THE CHANCE FOR SOME SHOWERS TONIGHT INTO TOMORROW MORNING...WITH AN ISOLATED RUMBLE OF THUNDER ALSO POSSIBLE. DRY WEATHER WILL RETURN FOR THE REST OF THE WEEK...ALONG WITH CONTINUED ABOVE NORMAL TEMPERATURES. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1230 PM EDT...TEMPERATURES ARE MORE LIKE THE FOURTH OF JULY THAN THE 4TH OF MAY...CLIMBING WELL INTO THE 70S...AND IN SOME CASES ALREADY HAVE SURPASSED 80 DEGREES. SATELLITE PICTURES INDICATED THAT SMALL CU FIELD DEVELOPING BUT NOTHING MORE. WE ARE WEAKLY CAPPED AT THIS TIME AND MOISTURE IS VERY LIMITED. FOR THIS UPDATE...DECIDED TO RAISE SOME TEMPERATURES 2-3 DEGREES HIGHER ACROSS CERTAIN SECTIONS...BASED ON CURRENT OBS AND THE POTENTIAL FOR DOWNSLOPE OFF THE CATSKILLS INTO THE HUDSON VALLEY THAT HAS NOT FULLY REALIZED. LOOK FOR HIGH TEMPERATURES IN THE MID OR EVEN UPPER 80S IN THE VALLEYS...(WARMEST IN THE MID HUDSON VALLEY)....70S TO LOWER 80S ACROSS THE HIGHER TERRAIN. A GUSTY SOUTHWEST WIND SHOULD KICK IN DURING THE AFTERNOON...WITH GUSTS UP TO 30-35 MPH POSSIBLE. RELATIVE HUMIDITY VALUES WILL BE VERY LOW...DIPPING INTO THE 20S AND EVEN SOME TEENS. SOME MID AND HIGH LEVEL CLOUDS SHOULD START TO INCREASE LATE IN THE DAY AS THE UPSTREAM COLD FRONT STARTS TO APPROACH...BUT IT LOOKS DRY FOR MOST OF THE AREA THROUGH AT LEAST THE EARLY EVENING HOURS. LATEST HRRR HAS SOME SHOWERS REACHING NORTHERN HERKIMER AND HAMILTON COUNTIES BETWEEN 5 AND 7 PM. SLIGHT CHANCE POPS FOR THE WESTERN ADIRONDACKS. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... THE COLD FRONT LOOKS TO MOVE ACROSS THE REGION TONIGHT INTO TUESDAY...AND SLOWLY DRIFT TO THE SOUTH THROUGH THE REMAINDER OF THE SHORT TERM PERIOD. AS A RESULT...SOME RAIN SHOWERS WILL BE POSSIBLE FOR TONIGHT INTO TUESDAY. THERE WON/T BE A LOT OF MOISTURE ASSOCIATED WITH THIS BOUNDARY...AND SHOWERS WON/T BE OVERLY WIDESPREAD. MOST AREAS WILL ONLY SEE A FEW PASSING LIGHT SHOWERS WITH THE COLD FRONTAL PASSAGE. BEST CHANCE FOR SEEING RAINFALL LOOKS NORTH AND WEST OF THE CAPITAL REGION. CLOUDS WILL INCREASE THIS EVENING...AND IT WILL BE FAIRLY CLOUDY INTO THE START OF TUESDAY. TEMPS OVERNIGHT WITH THE CLOUDS/SHOWERS WILL BE MILD WITH UPPER 40S TO UPPER 50S ACROSS THE REGION. SKIES WILL GRADUALLY CLEAR FROM NORTH TO SOUTH THROUGH THE DAY TUESDAY...ALTHOUGH SOUTHERN AREAS /CATSKILLS...MID HUDSON VALLEY...NW CT/ MAY WIND UP STAYING CLOUDY WITH A CHANCE OF SHOWERS THROUGH THE ENTIRE DAY TUESDAY AND INTO TUESDAY EVENING. TEMPS ON TUESDAY WILL STILL BE MILD...ALTHOUGH NOT QUITE AS WARM AS MONDAY...WITH HIGHS IN THE 70S. WITH THE FRONT JUST SOUTH OF THE AREA...THERE STILL MAY BE A LINGERING SHOWER AND SOME CLOUDS FOR FAR SOUTHERN AREAS ON TUESDAY NIGHT...BUT MOST AREAS WILL SEE A PARTLY TO MOSTLY CLEAR SKY ON TUESDAY NIGHT WITH DRY WEATHER. TEMPS WILL RANGE FROM THE 30S IN THE ADIRONDACKS TO THE UPPER 40S IN THE MID HUDSON VALLEY WHERE MORE CLOUDS WILL REMAIN. HIGH PRESSURE LOOKS TO BUILD IN FOR WEDNESDAY THROUGH WEDNESDAY NIGHT WITH MOSTLY CLEAR SKIES AS THE COLD FRONT FINALLY DRIFTS SOUTHWARD TOWARDS THE MID ATLANTIC REGION. DESPITE BEING BEHIND THE COLD FRONT...DAYTIME TEMPS WILL STILL BE QUITE WARM...WITH HIGHS ON WEDNESDAY BEING IN THE UPPER 60S TO UPPER 70S. MIN TEMPS ON WED NIGHT WILL GENERALLY BE IN THE 40S...ALTHOUGH A FEW 30S ARE POSSIBLE FOR THE HIGHER ELEVATIONS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... MODEL GUIDANCE IS IN GENERAL AGREEMENT THAT THE LONGWAVE PATTERN WILL FEATURE A RIDGE OVER THE NORTHEASTERN UNITED STATES WITH A TROUGH OVER THE WESTERN UNITED STATES FOR THE LATTER PART OF THE WEEK SHIFTING TO THE OVER THE PLAINS OVER THE WEEKEND. WHILE OFF THE SOUTHEAST COAST...AN AREA OF LOW PRESSURE UNDERNEATH THE RIDGE REMAIN NEARLY STATIONARY OFF THE COAST. DRY AND WARM WEATHER IS EXPECTED FOR THURSDAY AND FRIDAY. HOWEVER AS WE HEAD THROUGH MOTHER`S DAY WEEKEND THERE WILL BE INCREASING CHANCES FOR SOME SHOWERS AS A COLD FRONTAL BOUNDARY APPROACHES FROM THE GREAT LAKES REGION AND DEW POINTS RISE. THE REGION WILL BE IN THE WARM SECTOR OF THE APPROACHING SYSTEM SO ABOVE NORMAL TEMPERATURES ARE EXPECTED TO CONTINUE AS THE BOUNDARY APPROACHES. 850 MB TEMPERATURES ARE FORECAST TO WARM TO 12-15C OVER THE WEEKEND. OVERALL LOOKING FOR TEMPERATURES TO RUN 10 TO 15 DEGREES ABOVE NORMAL. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... MAINLY VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD...18Z TUESDAY. HIGH PRESSURE WILL DOMINATE THE WEATHER TODAY WITH A COLD FRONT BRINGING INCREASING CLOUDS AND A CHANCE OF SHOWERS TONIGHT INTO TOMORROW. GRADUAL CLEARING IS EXPECTED TOMORROW FOR MOST LOCATIONS BUT KPOU IS EXPECTED TO STAY CLOUDY WITH A THREAT OF SHOWERS CONTINUING AS THE FRONT SLOWS DOWN SOUTH OF THE ALBANY FORECAST AREA. GUSTY SOUTH TO SOUTHWESTERLY WINDS AT 10 TO 20 KNOTS ARE EXPECTED THIS AFTERNOON DIMINISHING TO SOUTHWEST AT 5 TO 10 KNOTS TONIGHT. WINDS WILL SHIFT TO NORTHWEST AT 5 TO 10 KNOTS TUESDAY MORNING WITH THE PASSAGE OF THE COLD FRONT. OUTLOOK... TUESDAY: LOW OPERATIONAL IMPACT. SLIGHT CHC -SHRA. TUESDAY NIGHT-FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX. && .FIRE WEATHER... A RED FLAG WARNING HAS BEEN ISSUED AT THE REQUEST OF THE NEW YORK STATE DEC FOREST RANGERS AND EMERGENCY MANAGEMENT AND THE MASSACHUSETTS DEPARTMENT OF CONSERVATION AND RECREATION. ALTHOUGH RED FLAG WARNINGS HAVE NOT BEEN ISSUED FOR SOUTHERN VERMONT AND NORTHWESTERN CONNECTICUT...LOCALIZED FIRE WEATHER ISSUES ARE POSSIBLE IN THOSE AREAS AS WELL. SIGNIFICANT RAINFALL /GREATER THAN A QUARTER OF AN INCH/ HAS NOT OCCURRED IN WELL OVER A WEEK ACROSS THE REGION AND STATE OFFICIALS HAVE NOTED THAT FOREST FUELS ARE RATHER DRY AT THIS TIME. RH VALUES ARE EXPECTED TO FALL TO 15 TO 25 PERCENT THIS AFTERNOON...AND S-SW WINDS OF 10 TO 15 MPH WITH GUSTS 25-35 MPH ARE EXPECTED...ALONG WITH AFTERNOON TEMPERATURES IN THE MID 70S TO UPPER 80S. AS A RESULT...ANY FIRES MAY BECOME DIFFICULT TO CONTROL THIS AFTERNOON INTO THIS EVENING. SPC HAS PLACED MUCH OF THE NORTHEAST IN AN ELEVATED FIRE WEATHER RISK AREA. RH VALUES ARE EXPECTED TO RECOVER TO 90 TO 100 PERCENT TONIGHT WITH SOME RAIN SHOWERS POSSIBLE. RAIN SHOWERS ARE EXPECTED TO BE LIGHT...AND MOST AREAS WON/T SEE A QUARTER OF AN INCH OF RAINFALL. WEST WINDS WILL BE AT 5 T0 15 MPH. WITH RAIN SHOWERS ENDING...AND SKIES STARTING TO CLEAR OUT...RH VALUES ON TUESDAY WILL FALL TO 30 TO 50 PERCENT...WITH THE LOWEST VALUES OVER THE ADIRONDACKS AND SRN VT. HOWEVER...WINDS WILL BE LIGHTER ON TUESDAY...WITH NW WINDS OF 5 TO 10 MPH. DRY WEATHER IS EXPECTED THROUGH THE REMAINDER OF THE WEEK...WITH RH VALUES DROPPING TO NEAR 30 PERCENT EACH AFTERNOON. HOWEVER...WINDS ARE EXPECTED TO BE FAIRLY LIGHT FOR THE REST OF THE WEEK. && .HYDROLOGY... NO HYDROLOGIC ISSUES ARE ANTICIPATED OVER THE NEXT FIVE DAYS. DRY WEATHER WILL BE IN PLACE TODAY WITH ABOVE NORMAL TEMPERATURES. A COLD FRONT WILL BRING SOME LIGHT RAIN SHOWERS TO THE REGION TONIGHT INTO TOMORROW. THE BEST CHANCE WILL BE FOR AREAS NORTH AND WEST OF THE CAPITAL REGION. BASIN AVERAGE RAINFALL WILL GENERALLY ONLY BE A TENTH OR TWO TENTH OF AN INCH. WITH VEGETATION STARTING TO GREEN UP OVER THE AREA...THIS RAINFALL WILL HAVE LITTLE TO NO IMPACT ON AREA RIVERS AND STREAMS. DRY WEATHER WILL BE IN PLACE FOR TUESDAY NIGHT THROUGH THE REMAINDER OF THE WEEK. AS A RESULT...RIVERS AND STREAMS WILL EITHER HOLD STEADY OR SLOWLY RECEDE THROUGH THE WEEK. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEB SITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR NYZ032-033- 038>043-047>054-058>061-063>066-082>084. MA...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR MAZ001-025. VT...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR VTZ013>015. && $$ SYNOPSIS...SND/FRUGIS/HWJIV NEAR TERM...SND/HWJIV SHORT TERM...FRUGIS LONG TERM...IAA AVIATION...SND FIRE WEATHER...FRUGIS HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1230 PM EDT MON MAY 4 2015 .SYNOPSIS... PLENTY OF SUNSHINE AND A WARM SOUTHWESTERLY FLOW WILL ALLOW FOR ABOVE NORMAL TEMPERATURES TODAY. AN APPROACHING COLD FRONT WILL BRING THE CHANCE FOR SOME SHOWERS TONIGHT INTO TOMORROW MORNING...WITH AN ISOLATED RUMBLE OF THUNDER ALSO POSSIBLE. DRY WEATHER WILL RETURN FOR THE REST OF THE WEEK...ALONG WITH CONTINUED ABOVE NORMAL TEMPERATURES. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1230 PM EDT...TEMPERATURES ARE MORE LIKE THE FOURTH OF JULY THAN THE 4TH OF MAY...CLIMBING WELL INTO THE 70S...AND IN SOME CASES ALREADY HAVE SURPASSED 80 DEGREES. SATELLITE PICTURES INDICATED THAT SMALL CU FIELD DEVELOPING BUT NOTHING MORE. WE ARE WEAKLY CAPPED AT THIS TIME AND MOISTURE IS VERY LIMITED. FOR THIS UPDATE...DECIDED TO RAISE SOME TEMPERATURES 2-3 DEGREES HIGHER ACROSS CERTAIN SECTIONS...BASED ON CURRENT OBS AND THE POTENTIAL FOR DOWNSLOPE OFF THE CATSKILLS INTO THE HUDSON VALLEY THAT HAS NOT FULLY REALIZED. LOOK FOR HIGH TEMPERATURES IN THE MID OR EVEN UPPER 80S IN THE VALLEYS...(WARMEST IN THE MID HUDSON VALLEY)....70S TO LOWER 80S ACROSS THE HIGHER TERRAIN. A GUSTY SOUTHWEST WIND SHOULD KICK IN DURING THE AFTERNOON...WITH GUSTS UP TO 30-35 MPH POSSIBLE. RELATIVE HUMIDITY VALUES WILL BE VERY LOW...DIPPING INTO THE 20S AND EVEN SOME TEENS. SOME MID AND HIGH LEVEL CLOUDS SHOULD START TO INCREASE LATE IN THE DAY AS THE UPSTREAM COLD FRONT STARTS TO APPROACH...BUT IT LOOKS DRY FOR MOST OF THE AREA THROUGH AT LEAST THE EARLY EVENING HOURS. LATEST HRRR HAS SOME SHOWERS REACHING NORTHERN HERKIMER AND HAMILTON COUNTIES BETWEEN 5 AND 7 PM. SLIGHT CHANCE POPS FOR THE WESTERN ADIRONDACKS. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... THE COLD FRONT LOOKS TO MOVE ACROSS THE REGION TONIGHT INTO TUESDAY...AND SLOWLY DRIFT TO THE SOUTH THROUGH THE REMAINDER OF THE SHORT TERM PERIOD. AS A RESULT...SOME RAIN SHOWERS WILL BE POSSIBLE FOR TONIGHT INTO TUESDAY. THERE WON/T BE A LOT OF MOISTURE ASSOCIATED WITH THIS BOUNDARY...AND SHOWERS WON/T BE OVERLY WIDESPREAD. MOST AREAS WILL ONLY SEE A FEW PASSING LIGHT SHOWERS WITH THE COLD FRONTAL PASSAGE. BEST CHANCE FOR SEEING RAINFALL LOOKS NORTH AND WEST OF THE CAPITAL REGION. CLOUDS WILL INCREASE THIS EVENING...AND IT WILL BE FAIRLY CLOUDY INTO THE START OF TUESDAY. TEMPS OVERNIGHT WITH THE CLOUDS/SHOWERS WILL BE MILD WITH UPPER 40S TO UPPER 50S ACROSS THE REGION. SKIES WILL GRADUALLY CLEAR FROM NORTH TO SOUTH THROUGH THE DAY TUESDAY...ALTHOUGH SOUTHERN AREAS /CATSKILLS...MID HUDSON VALLEY...NW CT/ MAY WIND UP STAYING CLOUDY WITH A CHANCE OF SHOWERS THROUGH THE ENTIRE DAY TUESDAY AND INTO TUESDAY EVENING. TEMPS ON TUESDAY WILL STILL BE MILD...ALTHOUGH NOT QUITE AS WARM AS MONDAY...WITH HIGHS IN THE 70S. WITH THE FRONT JUST SOUTH OF THE AREA...THERE STILL MAY BE A LINGERING SHOWER AND SOME CLOUDS FOR FAR SOUTHERN AREAS ON TUESDAY NIGHT...BUT MOST AREAS WILL SEE A PARTLY TO MOSTLY CLEAR SKY ON TUESDAY NIGHT WITH DRY WEATHER. TEMPS WILL RANGE FROM THE 30S IN THE ADIRONDACKS TO THE UPPER 40S IN THE MID HUDSON VALLEY WHERE MORE CLOUDS WILL REMAIN. HIGH PRESSURE LOOKS TO BUILD IN FOR WEDNESDAY THROUGH WEDNESDAY NIGHT WITH MOSTLY CLEAR SKIES AS THE COLD FRONT FINALLY DRIFTS SOUTHWARD TOWARDS THE MID ATLANTIC REGION. DESPITE BEING BEHIND THE COLD FRONT...DAYTIME TEMPS WILL STILL BE QUITE WARM...WITH HIGHS ON WEDNESDAY BEING IN THE UPPER 60S TO UPPER 70S. MIN TEMPS ON WED NIGHT WILL GENERALLY BE IN THE 40S...ALTHOUGH A FEW 30S ARE POSSIBLE FOR THE HIGHER ELEVATIONS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... MODEL GUIDANCE IS IN GENERAL AGREEMENT THAT THE LONGWAVE PATTERN WILL FEATURE A RIDGE OVER THE NORTHEASTERN UNITED STATES WITH A TROUGH OVER THE WESTERN UNITED STATES FOR THE LATTER PART OF THE WEEK SHIFTING TO THE OVER THE PLAINS OVER THE WEEKEND. WHILE OFF THE SOUTHEAST COAST...AN AREA OF LOW PRESSURE UNDERNEATH THE RIDGE REMAIN NEARLY STATIONARY OFF THE COAST. DRY AND WARM WEATHER IS EXPECTED FOR THURSDAY AND FRIDAY. HOWEVER AS WE HEAD THROUGH MOTHER`S DAY WEEKEND THERE WILL BE INCREASING CHANCES FOR SOME SHOWERS AS A COLD FRONTAL BOUNDARY APPROACHES FROM THE GREAT LAKES REGION AND DEW POINTS RISE. THE REGION WILL BE IN THE WARM SECTOR OF THE APPROACHING SYSTEM SO ABOVE NORMAL TEMPERATURES ARE EXPECTED TO CONTINUE AS THE BOUNDARY APPROACHES. 850 MB TEMPERATURES ARE FORECAST TO WARM TO 12-15C OVER THE WEEKEND. OVERALL LOOKING FOR TEMPERATURES TO RUN 10 TO 15 DEGREES ABOVE NORMAL. && .AVIATION /16Z MONDAY THROUGH FRIDAY/... THE HIGH PRESSURE OVER THE REGION WILL SHIFT TO THE SOUTHEAST OF THE AREA TODAY AS A COLD FRONT GRADUALLY APPROACHES FROM THE GREAT LAKES REGION. FEW TO SCATTERED MID LEVEL CLOUDS WILL CONTINUE TO MOVE ACROSS THE AREA THIS MORNING. CLOUDS WILL BE ON THE INCREASE TODAY ESPECIALLY THIS AFTERNOON INTO THE EVENING AS THE COLD FRONT MOVES CLOSER TO THE AREA. CHANCES FOR SHOWERS WILL BE IN THE INCREASE AS THE BOUNDARY MOVES INTO AND THROUGH THE AREA. HAVE ADDRESSED THREAT WITH VICINITY SHOWERS IN TAFS. SOUTH TO SOUTHWESTERLY FLOW WILL DEVELOP THIS MORNING AND WILL INCREASE IN SPEED AND BECOME GUSTY AS THE MORNING PROGRESSES. THE WINDS WILL WEAKEN SOME DURING THE EVENING LOSING THEIR GUSTINESS. WINDS WILL SHIFT TO WEST-NORTHWEST WITH THE PASSAGE OF THE BOUNDARY. OUTLOOK... TUESDAY: LOW OPERATIONAL IMPACT. SLIGHT CHC -SHRA. TUESDAY NIGHT-FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX. && .FIRE WEATHER... A RED FLAG WARNING HAS BEEN ISSUED AT THE REQUEST OF THE NEW YORK STATE DEC FOREST RANGERS AND EMERGENCY MANAGEMENT AND THE MASSACHUSETTS DEPARTMENT OF CONSERVATION AND RECREATION. ALTHOUGH RED FLAG WARNINGS HAVE NOT BEEN ISSUED FOR SOUTHERN VERMONT AND NORTHWESTERN CONNECTICUT...LOCALIZED FIRE WEATHER ISSUES ARE POSSIBLE IN THOSE AREAS AS WELL. SIGNIFICANT RAINFALL /GREATER THAN A QUARTER OF AN INCH/ HAS NOT OCCURRED IN WELL OVER A WEEK ACROSS THE REGION AND STATE OFFICIALS HAVE NOTED THAT FOREST FUELS ARE RATHER DRY AT THIS TIME. RH VALUES ARE EXPECTED TO FALL TO 15 TO 25 PERCENT THIS AFTERNOON...AND S-SW WINDS OF 10 TO 15 MPH WITH GUSTS 25-35 MPH ARE EXPECTED...ALONG WITH AFTERNOON TEMPERATURES IN THE MID 70S TO UPPER 80S. AS A RESULT...ANY FIRES MAY BECOME DIFFICULT TO CONTROL THIS AFTERNOON INTO THIS EVENING. SPC HAS PLACED MUCH OF THE NORTHEAST IN AN ELEVATED FIRE WEATHER RISK AREA. RH VALUES ARE EXPECTED TO RECOVER TO 90 TO 100 PERCENT TONIGHT WITH SOME RAIN SHOWERS POSSIBLE. RAIN SHOWERS ARE EXPECTED TO BE LIGHT...AND MOST AREAS WON/T SEE A QUARTER OF AN INCH OF RAINFALL. WEST WINDS WILL BE AT 5 T0 15 MPH. WITH RAIN SHOWERS ENDING...AND SKIES STARTING TO CLEAR OUT...RH VALUES ON TUESDAY WILL FALL TO 30 TO 50 PERCENT...WITH THE LOWEST VALUES OVER THE ADIRONDACKS AND SRN VT. HOWEVER...WINDS WILL BE LIGHTER ON TUESDAY...WITH NW WINDS OF 5 TO 10 MPH. DRY WEATHER IS EXPECTED THROUGH THE REMAINDER OF THE WEEK...WITH RH VALUES DROPPING TO NEAR 30 PERCENT EACH AFTERNOON. HOWEVER...WINDS ARE EXPECTED TO BE FAIRLY LIGHT FOR THE REST OF THE WEEK. && .HYDROLOGY... NO HYDROLOGIC ISSUES ARE ANTICIPATED OVER THE NEXT FIVE DAYS. DRY WEATHER WILL BE IN PLACE TODAY WITH ABOVE NORMAL TEMPERATURES. A COLD FRONT WILL BRING SOME LIGHT RAIN SHOWERS TO THE REGION TONIGHT INTO TOMORROW. THE BEST CHANCE WILL BE FOR AREAS NORTH AND WEST OF THE CAPITAL REGION. BASIN AVERAGE RAINFALL WILL GENERALLY ONLY BE A TENTH OR TWO TENTH OF AN INCH. WITH VEGETATION STARTING TO GREEN UP OVER THE AREA...THIS RAINFALL WILL HAVE LITTLE TO NO IMPACT ON AREA RIVERS AND STREAMS. DRY WEATHER WILL BE IN PLACE FOR TUESDAY NIGHT THROUGH THE REMAINDER OF THE WEEK. AS A RESULT...RIVERS AND STREAMS WILL EITHER HOLD STEADY OR SLOWLY RECEDE THROUGH THE WEEK. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEB SITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR NYZ032-033- 038>043-047>054-058>061-063>066-082>084. MA...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR MAZ001-025. VT...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR VTZ013>015. && $$ SYNOPSIS...SND/FRUGIS/HWJIV NEAR TERM...SND/HWJIV SHORT TERM...FRUGIS LONG TERM...IAA AVIATION...IAA FIRE WEATHER...FRUGIS/SND/HWJIV HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
255 PM CDT MON MAY 4 2015 .SHORT TERM...(TONIGHT) ISSUED AT 245 PM CDT MON MAY 4 2015 FRONTAL BOUNDARY EXTENDING FROM SOUTHERN LAKE MICHIGAN TO NORTHERN KANSAS WILL SINK SOUTHWARD...EVENTUALLY STALLING NEAR THE I-72 CORRIDOR LATER THIS EVENING. SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY...WITH MOST MODEL SOLUTIONS SUGGESTING THE GREATEST AREAL COVERAGE OF PRECIP ACROSS THE NORTHERN HALF OF THE KILX CWA. HRRR IS SHOWING WIDELY SCATTERED STORMS DEVELOPING OVER THE NEXT COUPLE OF HOURS...WITH THE CONVECTION BECOMING MORE WIDESPREAD AFTER SUNSET AS A WEAK LOW-LEVEL JET DEVELOPS. HAVE ADJUSTED RAIN CHANCES ACCORDINGLY...WITH LIKELY POPS ALONG/NORTH OF I-72 TAPERING DOWN TO JUST SLIGHT CHANCE ALONG/SOUTH OF I-70. && .LONG TERM...(TUESDAY THROUGH MONDAY) ISSUED AT 245 PM CDT MON MAY 4 2015 AN UPPER LEVEL RIDGE IS EXPECTED TO AMPLIFY OVER THE CENTER OF THE NATION STARTING ON TUESDAY WHICH SHOULD PUSH THE BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS NORTH OF THE FORECAST AREA...AT LEAST INTO THURSDAY. SHORTWAVE ENERGY IS THEN FORECAST TO EJECTS NORTH OUT OF THE SOUTHERN PLAINS AND BRING ABOUT A CHANCE FOR MORE SHOWERS AND THUNDERSTORMS...ESPECIALLY ACROSS OUR WEST...THURSDAY NIGHT INTO FRIDAY. A MORE POTENT 500 MB TROF IS THEN FORECAST TO SLOWLY TRACK OUT OF THE ROCKIES DURING THE WEEKEND BRINGING PERIODS OF SHOWERS AND THUNDERSTORMS TO THE FORECAST AREA. MOST MODELS TRACK THIS LOW NORTH-NORTHEAST ON SUNDAY SUGGESTING THE MORE SIGNIFICANT LIFT TO REMAIN WEST OF OUR AREA UNTIL LATE SUNDAY OR MONDAY OF NEXT WEEK WHEN THE SYSTEM WILL SWING A COLD FRONT THROUGH CENTRAL ILLINOIS. UNTIL THEN...WARM TEMPERATURES TO PREVAIL WITH THE SHOWER AND STORM CHANCES ACROSS THE FAR NORTH TOMORROW AS THE FRONT RETREATS BACK TO THE NORTH...AND THEN RAIN CHANCES RETURN LATE THU INTO FRIDAY AND HOLDS THROUGH EARLY NEXT WEEK BEFORE WE FINALLY GET A CHANGE IN AIR MASS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1258 PM CDT MON MAY 4 2015 MODELS CONTINUE TO SHOW FRONTAL BOUNDARY CURRENTLY ACROSS NORTHERN ILLINOIS DROPPING SLOWLY SOUTHWARD INTO THE AREA TONIGHT. SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG/NEAR THIS BOUNDARY AFTER 01/02Z...WITH THE LONGEST PERIOD OF RAIN EXPECTED AT THE NORTHERN TERMINALS OF KPIA AND KBMI. WILL CARRY PREDOMINANT SHOWERS AT THESE SITES THROUGHOUT THE NIGHT. BIG QUESTION WILL BE WHETHER OR NOT CEILINGS WILL LOWER INTO THE MVFR CATEGORY NORTH OF THE FRONT. NAM FORECAST SOUNDINGS CONTINUE TO SHOW VFR CEILINGS EVEN AT KPIA/KBMI WHERE WINDS BECOME E/NE LATER THIS EVENING, WHILE THE HRRR HINTS AT LOWER CEILINGS AROUND 2500FT. LATEST REGIONAL OBS SHOW A FEW MVFR CEILINGS NORTH OF THE FRONT ACROSS CENTRAL IOWA, SO DO NOT WANT TO COMPLETELY IGNORE THE POSSIBILITY. HAVE THEREFORE INCLUDED SCT025 AT BOTH KPIA AND KBMI AFTER 04Z AND WILL CONTINUE TO MONITOR LATER OBS AND MODEL RUNS TO MAKE A FINAL DETERMINATION. ALL MODELS SHOW THE BOUNDARY SHIFTING BACK NORTHWARD TUESDAY MORNING, RESULTING IN DIMINISHING RAIN CHANCES AND WINDS RETURNING TO THE S/SE. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BARNES LONG TERM...SMITH AVIATION...BARNES
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1258 PM CDT MON MAY 4 2015 .UPDATE... ISSUED AT 1045 AM CDT MON MAY 4 2015 15Z/10AM SURFACE ANALYSIS SHOWS STATIONARY FRONTAL BOUNDARY EXTENDING FROM SOUTHERN LAKE MICHIGAN TO KANSAS. WIDELY SCATTERED SHOWERS ARE CURRENTLY ONGOING NEAR AND JUST SOUTH OF THE FRONT ACROSS MUCH CENTRAL ILLINOIS...ALTHOUGH AREAL COVERAGE OF PRECIP HAS BEEN DIMINISHING OVER THE PAST COUPLE OF HOURS. 12Z NAM SUGGESTS THE GREATEST INSTABILITY AND STRONGEST LOW-LEVEL WIND SHEAR WILL OVERLAP NEAR AN AREA OF LOW PRESSURE ALONG THE BOUNDARY FROM SOUTHERN IOWA SOUTHWESTWARD INTO KANSAS LATER THIS AFTERNOON. THINK THIS WILL BE THE PRIMARY AREA WHERE WIDESPREAD CONVECTION WILL DEVELOP...WITH ONLY SCATTERED SHOWERS/STORMS FURTHER EAST ACROSS ILLINOIS WHERE INSTABILITY/SHEAR WILL BE WEAKER. HRRR SHOWS THIS TREND AS WELL...WITH CONVECTION DEVELOPING/SPREADING EASTWARD ACROSS THE NORTHERN HALF OF THE KILX CWA AFTER SUNSET. HAVE MADE SOME MINOR ADJUSTMENTS TO THE FORECAST...MAINLY TO FEATURE SCATTERED POPS ALONG/NORTH OF I-72 TODAY AND ONLY ISOLATED FURTHER SOUTH. BETTER RAIN CHANCES WILL ARRIVE TONIGHT. WITH SOME PARTIAL SUNSHINE...AFTERNOON HIGH TEMPERATURES WILL RISE INTO THE UPPER 70S AND LOWER 80S. && .SHORT TERM...(TODAY) ISSUED AT 342 AM CDT MON MAY 4 2015 OUTFLOW BOUNDARY FROM CONVECTION THAT DEVELOPED AHEAD OF A FRONTAL BOUNDARY EXTENDING THROUGH THE GREAT LAKES AND INTO THE CENTRAL PLAINS HAS MOVED INTO PORTIONS OF THE CENTRAL IL FORECAST AREA...EXTENDING FROM NEAR PEORIA TO PONTIAC. BOUNDARY CONTINUES TO TRIGGER SCATTERED THUNDERSTORMS BEHIND IT...WHILE AHEAD LIGHT SHOWERS ARE WIDELY SCATTERED ACROSS CENTRAL IL. MID-LEVEL INSTABILITY ACROSS THE REGION WILL CAUSE SHOWERS AND THUNDERSTORMS TO CONTINUE TO DEVELOP ACROSS MUCH OF CENTRAL IL MAINLY FROM I-70 NORTHWARD THROUGH MORNING. A POSSIBLE LULL IN PRECIPITATION INDICATED BY MODEL FORECASTS LATE MORNING AS CURRENT AREA OF CONVECTION SHIFTS NORTHEASTWARD AND RE-DEVELOPMENT OF CONVECTION TAKES PLACE ALONG THE APPROACHING FRONTAL BOUNDARY FOR THE AFTERNOON. SPC CONTINUES TO ADVERTISE A MARGINAL RISK FOR SEVERE STORMS CONTAINING HAIL/STRONG WIND GUSTS THIS AFTERNOON/EVENING THROUGH MUCH OF CENTRAL AND NORTHERN IL NEAR THE FRONTAL BOUNDARY WHERE AT LEAST SOME OVERLAP OF MODERATE BULK SHEAR MAY COMBINE WITH 1000-2000 J CAPE. HIGH TEMPERATURES QUITE WARM AGAIN TODAY...UPPER 70S TO LOW 80S...WITH BREEZY SW WINDS 10-15 MPH. .LONG TERM...(TONIGHT THROUGH SUNDAY) ISSUED AT 342 AM CDT MON MAY 4 2015 SOME CONVECTION SETTLING INTO THE MIDWEST THIS MORNING ALONG AND AHEAD OF THE BOUNDARY JUST TO THE NORTHWEST. SAME BOUNDARY PROVIDING THE FOCUS FOR SHOWERS TODAY WILL KEEP THE THREAT FOR SOME SHOWERS AND THUNDERSTORMS THROUGH THE OVERNIGHT IN THE NORTHERN HALF OF THE STATE. EXACT LOCATION OF THE STALLED BOUNDARY VARIES A BIT FROM MODEL TO MODEL. SMALL WAVES MOVING ALONG THE BOUNDARY WILL KEEP PRECIP CHANCES IN THE NORTHERN TIER OF THE STATE THROUGH TUESDAY. HIGH PRESSURE SLOWLY BUILDING IN WITH SOME SOUTHERLY WINDS PUSHING THE FRONT BACK TO THE NORTH AND OUT OF THE FORECAST AREA FOR TUESDAY NIGHT THROUGH WED NIGHT. PRECIP CHANCES SLOWLY EDGING BACK INTO CENTRAL ILLINOIS AS AN UPPER LEVEL WAVE PUSHES OUT OF THE SW. THE ENERGY IS PART OF A GENERAL PATTERN SHIFT TO MORE SOUTHWESTERLY FLOW WITH THE UPPER LEVEL TROF DIGGING BACK IN OVER THE SWRN CONUS. THE SFC LOW WITH THAT STORM MOVES OUT INTO THE UPPER MIDWEST AND INTO CANADA BY THE END OF THE WEEK, BUT IN SHIFTING TO MORE SOUTHWESTERLY FLOW ALOFT, OPENS THE DOOR TO A SERIES OF SHORTWAVES THAT KEEP THE FORECAST WET FOR THE END OF THE WORK WEEK AND INTO THE WEEKEND. TEMPS RATHER WARM THROUGH THE FORECAST WITH OVERCAST AND RAINY SKIES KEEPING THE OVERNIGHT LOWS UP A BIT, BUT LIKELY NOT NEARLY AS WARM AS THE TREND IN THE GUIDANCE. HAVE KNOCKED THEM DOWN A COUPLE DEGREES. SOUTHERLY FLOW AND A RELATIVELY WARM AIRMASS KEEPING THE HIGHS A BIT ABOVE NORMS. HOWEVER, WITH THE LIFTING OF THE DEEP TROF OVER THE SW INTO THE GREAT LAKES, THE WARMER AIRMASS IS SHUNTED OFF TO THE EAST AND COOLER AIR MOVES INTO THE MIDWEST AT LEAST BRIEFLY AT THE END OF THE FORECAST PD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1258 PM CDT MON MAY 4 2015 MODELS CONTINUE TO SHOW FRONTAL BOUNDARY CURRENTLY ACROSS NORTHERN ILLINOIS DROPPING SLOWLY SOUTHWARD INTO THE AREA TONIGHT. SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG/NEAR THIS BOUNDARY AFTER 01/02Z...WITH THE LONGEST PERIOD OF RAIN EXPECTED AT THE NORTHERN TERMINALS OF KPIA AND KBMI. WILL CARRY PREDOMINANT SHOWERS AT THESE SITES THROUGHOUT THE NIGHT. BIG QUESTION WILL BE WHETHER OR NOT CEILINGS WILL LOWER INTO THE MVFR CATEGORY NORTH OF THE FRONT. NAM FORECAST SOUNDINGS CONTINUE TO SHOW VFR CEILINGS EVEN AT KPIA/KBMI WHERE WINDS BECOME E/NE LATER THIS EVENING, WHILE THE HRRR HINTS AT LOWER CEILINGS AROUND 2500FT. LATEST REGIONAL OBS SHOW A FEW MVFR CEILINGS NORTH OF THE FRONT ACROSS CENTRAL IOWA, SO DO NOT WANT TO COMPLETELY IGNORE THE POSSIBILITY. HAVE THEREFORE INCLUDED SCT025 AT BOTH KPIA AND KBMI AFTER 04Z AND WILL CONTINUE TO MONITOR LATER OBS AND MODEL RUNS TO MAKE A FINAL DETERMINATION. ALL MODELS SHOW THE BOUNDARY SHIFTING BACK NORTHWARD TUESDAY MORNING, RESULTING IN DIMINISHING RAIN CHANCES AND WINDS RETURNING TO THE S/SE. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARNES SHORT TERM...ONTON LONG TERM...HJS AVIATION...BARNES
AREA FORECAST DISCUSSION
NWS GOODLAND KS
222 PM MDT MON MAY 4 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 220 PM MDT MON MAY 4 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW DEEPENING TROUGH OVER SOUTHERN CALIFORNIA WITH SW FLOW FROM THE GULF OF ALASKA AND ACROSS THE CENTRAL/HIGH PLAINS. MOIST PLUME EXTENDS FROM THE GREAT BASIN ACROSS THE OHIO RIVER VALLEY WITH ADDITIONAL MOISTURE FEEDING IN THE PLAINS FROM THE GULF OF MEXICO. AT THE SURFACE A STATIONARY FRONT EXTENDS FROM NORTHEAST KANSAS TO SOUTHEAST COLORADO AND LIES JUST SOUTHEAST OF OUR CWA...WITH BAROCLINIC ZONE EXTENDING NORTH INTO THE SE PART OF OUR CWA. THUNDERSTORMS ARE BEGINNING TO DEVELOP ALONG THIS FRONTAL ZONE TOWARDS THE SOUTHEAST PART OF OUR CWA. THIS AFTERNOON-EVENING...ALONG THIS FRONTAL ZONE ANALYSIS INDICATES ML CAPE VALUES RANGING FROM 1500 J/KG IN THE WARM SECTOR TO 500 J/KG IN OUR SE CWA. BULK SHEER IS APPROXIMATELY 30-35KT...SO DEPENDING ON POSITION OF FRONT (CURRENTLY ADVERTISED TO SLIDE NORTH INTO OUR SOUTHEAST)...THERE IS THE POTENTIAL FOR A FEW STRONGER THUNDERSTORMS...POSSIBLY SEVERE WITH LARGE HAIL/DAMAGING WINDS MAIN THREAT. IF FRONT WERE TO LIFT NORTH AS WARM FRONT WE COULD SEE BETTER SB/ML CAPE AND THE POSSIBILITY FOR A FEW MORE ORGANIZED CELLS IN THE SOUTHEAST. ANALYSIS ALSO INDICATES PWAT VALUES ALREADY IN EXCESS OF 1" OVER OUR EAST. STORM MOTIONS WILL BE ROUGHLY TANGENTIAL/PARALLEL THIS AFTERNOON BECOMING PERPENDICULAR TO FRONTAL ZONE THIS EVENING. AS THIS TRANSITION OCCURS THERE IS THE FOR BACKBUILDING OR TRAINING AS VERY MOIST/UNSTABLE AIR IN THE WARM SECTOR FEEDS NORTH. THERE COULD BE A THREAT FOR FLASH FLOODING IF THIS SCENARIO PLAYS OUT. EITHER WAY WITH VERY MOIST AIR MASS AND INCREASING ELEVATED INSTABILITY...THUNDERSTORMS COULD BE VERY EFFICIENT RAINFALL PRODUCERS. TONIGHT-TUESDAY...UPSTREAM AREAS OF MID LEVEL VORTICITY WILL ROTATE INTO THE CWA WITH INCREASING LIFT LATE THIS EVENING INTO THE OVERNIGHT. AS TROUGH CONTINUES TO DEEPEN OVER THE SW US AND MOVE EAST WE WILL CONTINUE TO SEE VERY GOOD FORCING/MOISTURE ROTATES THROUGH THE REGION. LARGE SCALE Q VECTOR FIELDS INDICATED FORCING INCREASING THROUGH THE NIGHT AND OMEGA/MOISTURE CONVERGENCE FIELDS SHOW SUPPORT FOR INCREASING COVERAGE/COMPLEX OF SHOWERS THUNDERSTORMS. ELEVATED INSTABILITY TRANSITIONS NORTHWARD AND WEAKENS...HOWEVER THERE IS ENOUGH TO KEEP THUNDER MENTION IN PLACE THROUGH TUESDAY AFTERNOON. WHILE GUIDANCE IS IN AGREEMENT ON GENERAL LARGE SCALE PATTERN THE MAIN DIFFERENCES ARE ON TIMING OF POTENTIAL PERIODS OF HEAVIER PRECIP...WITH BEST PRECIP SIGNAL AND MOISTURE PROFILES OVERLAPPING TUESDAY MORNING THROUGH TUESDAY AFTERNOON ACROSS THE WESTERN 2/3 OF THE CWA (THOUGH ECMWF MIGHT BE A LITTLE EAST). THERE WILL BE MODERATE/ELEVATED INSTABILITY IN PLACE THROUGH THE DAY TUESDAY...SO STRONG TO SEVERE THUNDERSTORMS WILL STILL BE POSSIBLE AGAIN...THOUGH SEVERE POTENTIAL MIGHT NOT BE AS GOOD AS TODAY WITH WIDESPREAD SHOWERS AND STRATUS LIMITING SURFACE BASED PARCELS AND ANY ACTIVITY LIKELY EMBEDDED WITH OTHER SHOWER CLUSTERS. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 124 PM MDT MON MAY 4 2015 MAIN TROUGH AXIS WILL LIFT NORTHEAST ACROSS THE AREA TUESDAY NIGHT WITH GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUING. AFTER MIDNIGHT...GENERAL TREND WILL BE FOR A WEST TO EAST END OF THE PRECIPITATION AS DRY SLOT WORKS IN BEHIND THE TROUGH. AFTER A LULL WEDNESDAY MORNING...WRAPAROUND PRECIPITATION WILL MOVE IN FROM COLORADO WEDNESDAY AFTERNOON AND BECOME WIDESPREAD WEDNESDAY NIGHT. A COLD FRONT WILL ALSO MOVE THROUGH WEDNESDAY NIGHT WHICH WILL PROVIDE A FOCUS FOR THUNDERSTORMS IN THE EVENING...BUT THE POST FRONTAL ENVIRONMENT HAS ONLY LIMITED ELEVATED INSTABILITY AND EXPECT ONLY ISOLATED THUNDERSTORMS THROUGH THURSDAY MORNING. HOWEVER BY THURSDAY AFTERNOON SBCAPE INCREASES ONCE AGAIN AND A COMBINATION OF MOIST LOW LEVEL UPSLOPE AND ANOTHER SHORTWAVE TROUGH IN THE SOUTHWESTERLY FLOW ALOFT WILL RESULT IN THUNDERSTORM DEVELOPMENT IN EASTERN COLORADO WHICH WILL MOVE INTO NORTHWEST KANSAS AND SOUTHWEST NEBRASKA THURSDAY EVENING. SEVERE THREAT WILL DEPEND ON HOW MUCH INSTABILITY CAN DEVELOP AFTER A CLOUDY MORNING...BUT DEEP LAYER SHEAR WOULD BE SUPPORTIVE OF ORGANIZED UPDRAFTS THROUGH EARLY EVENING BEFORE BOUNDARY LAYER DECOUPLES WITH NOCTURNAL COOLING. OVERALL PATTERN CHANGES LITTLE ON FRIDAY ALTHOUGH MODELS SHOWING ONLY MINIMAL SBCAPE AVAILABLE SO SEVERE THREAT MAY NOT BE AS GREAT. ANOTHER STRONG UPPER LOW WILL KICK OUT OF THE DESERT SOUTHWEST ON SATURDAY WITH A NEGATIVE TILT AND PROVIDE THE SYNOPTIC SCALE FORCING FOR THUNDERSTORMS. THE PATTERN SUGGESTS A SEVERE THREAT WITH MODELS SHOWING DEEP LAYER SHEAR OF OVER 50KTS AND SUFFICIENT INSTABILITY FOR SUPERCELLS. IF CURRENT TIMING TRENDS CONTINUE WOULD EXPECT TO SEE A DRY SLOT SATURDAY NIGHT FOLLOWED BY WRAPAROUND PRECIPITATION CHANCES ON SUNDAY. THE PATTERN FINALLY CHANGES BY EARLY NEXT WEEK WITH SUBTLE SHORTWAVE RIDGING IN A ZONAL FLOW WHICH WOULD TRANSLATE TO DRY CONDITIONS AND SEASONABLE TEMPERATURES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1129 AM MDT MON MAY 4 2015 SCATTERED LIGHT SHOWERS WILL CONTINUE TO IMPACT BOTH TERMINALS THROUGH MOST OF THE DAY...WITH THUNDERSTORM ACTIVITY DEVELOPING BY LATE AFTERNOON. SHOWER/THUNDERSTORM COVERAGE WILL INCREASE DURING THE EVENING WITH VERY MOIST AIR MASS ON EASTERN EDGE OF STRONG UPPER LOW BRINGING LOW STRATUS...MODERATE PRECIPITATION...AND LIGHT FOG. EXPECT VFR CONDITIONS TO TRANSITION TO IFR THROUGH THE NIGHT...WITH LIFR CIGS POSSIBLE BY 12Z. LIGHT FOG OR MODERATE TO HEAVY RAINFALL COULD REDUCING VISIBILITIES BELOW 3SM ESPECIALLY IN THE 10-18Z TIME PERIOD. THIS IS A COMPLICATED AVIATION FORECAST AND HIGHLY DEPENDENT ON LOCATION OF MORE INTENSE RAINFALL...SO I STARTED SHOWING TRENDS BASED ON CURRENT GUIDANCE...HOWEVER WASNT CONFIDENT ENOUGH TO INTRODUCE PREVAILING LIFR CONDITIONS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...024 AVIATION...DR
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1242 PM CDT MON MAY 4 2015 .AVIATION... VFR FLIGHT CATEGORIES ARE EXPECTED THROUGH THE AFTERNOON AND THE EVENING WITH CLOUDS AND CEILINGS AROUND 4-5 KFT. THEN DURING THE LATE EVENING AND EARLY MORNING HOURS MVFR CEILINGS AND VISIBILITIES WILL MOVE OVER THE AREA AND INCREASE BACK TO VFR DURING THE LATE MORNING HOURS. WINDS WILL BE SOUTH TO SOUTHEAST 8-13 KNOTS DROPPING OFF INTO THE THE EVENING AROUND 4-8 KTNOS. WINDS PICK BACK UP TO 10-15 KNOTS AFTER 06/14Z TUESDAY. /06/ && .PREV DISCUSSION... /ISSUED 1059 AM CDT MON MAY 4 2015/ DISCUSSION... TEMPERATURES ARE CLIMBING NICELY UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES THIS MORNING...ALREADY IN THE MID 70S TO NEAR 80 DEGREES IN SOME LOCATIONS AS OF 16Z. CURRENT FORECAST SEEMS TO HAVE A GOOD HANDLE ON AFTERNOON HIGHS AND HAVE ONLY MADE MINOR CHANGES TO WIND AND DEW POINT GRIDS TO BETTER MIMIC CURRENT OBSERVATIONS AND TRENDS GOING FORWARD. NO OTHER ADJUSTMENTS ARE NEEDED AT THIS TIME. UPDATED PRODUCTS HAVE ALREADY BEEN SENT. /19/ PREV DISCUSSION... /ISSUED 546 AM CDT MON MAY 4 2015/ AVIATION... VFR CONDITIONS TO PREVAIL TODAY. CURRENT IR IMAGERY SHOWING THE INTRUSION OF SOME HIGH/THIN CIRRUS FROM DEBRIS EARLIER IN THE PLAINS. ALSO EVIDENT ACROSS PORTIONS OF NE TX AND SW AR/N LA TERMINALS IS SOME CLOUD COVER IN THE 6-8KFT LEVEL. LOW LEVEL MOISTURE WILL AGAIN BE ON THE INCREASE TODAY WITH SCT CU FIELD EXPECTED TO DEVELOP IN THE 16-18Z TIMEFRAME AND ADVANCE NORTHWARD. A FEW CEILINGS WILL BE POSSIBLE AT THESE HEIGHTS THROUGHOUT THE DAY BUT SCT DECKS BEST DESCRIBE WHAT WILL MOSTLY OCCUR. CANNOT RULE OUT SOME VERY ISOLATED SHOWER ACTIVITY NEAR OUR NE TX TERMINALS TODAY AS THE HRRR IS SHOWING THIS POSSIBILITY. COVERAGE CERTAINLY WILL NOT SUPPORT THE MENTION OF THIS IN OUR 12Z TAF PACKAGE. LOOK FOR WINDS FROM THE SE IN THE 6-12KT RANGE TODAY WITH A FEW HIGHER GUSTS POSSIBLE ACROSS MAINLY OUR NE TX TERMINAL LOCATIONS. SOME INDICATIONS OF POSSIBLE MVFR CEILINGS INCREASING FROM THE SOUTH AFTER MIDNIGHT TONIGHT ACROSS OUR NE TX TERMINAL LOCATIONS. FOR NOW HAVE JUST MADE MENTION OF THIS AT THE LFK TERMINAL. 13 PREV DISCUSSION... /ISSUED 321 AM CDT MON MAY 4 2015/ DISCUSSION... UPPER RIDGING HOLDING IN PLACE ACROSS AREA...WITH SFC HIGH BEGINNING TO DRIFT EAST OF MS RIVER VALLEY. LOW LVL SE-S FLOW TO INCREASE GRADUALLY NEXT COUPLE OF DAYS...AND WILL BEGIN TO INTRODUCE LOW CHANCES FOR CONVECTION FROM THE WEST...BEGINNING TUESDAY. NAM MODEL TOO AGGRESSIVE WITH DEEP MOISTURE...AS EAST TO WEST FRONTAL BOUNDARY WILL REMAIN OVER CENTRAL PLAINS...AND DEVELOPING DRY LINE REMAINING OVER FAR WEST TX THRU THE WEEK. ALTHOUGH DECENT LOW LVL DIRECTIONAL SHEAR WILL SET UP...WILL LACK SPEED IN LOW LVL JET AND NOT EXPECTING MUCH IN SVR WX WITH THE MOSTLY DIURNAL CONVECTION THAT MAY OCCUR. AFTN HIGHS IN LOWER TO MID 80S WILL LIKELY PERSIST...YET OVERNIGHT LOWS MAY EDGE INTO MID TO UPPER 60S AS MOISTURE GRADUALLY DEEPENS. SFC LOW TO DEVELOP OVER PANHANDLES BY WEEKEND...AND AS THIS LOW BEGINS TO KICK OUT TO NE LATE IN WEEKEND...FRONTAL BOUNDARY WILL APPROACH REGION. IN THE MEANTIME...A VERY WEAK SEA BREEZE FRONT MAY BRING ISOLD SHOWERS INTO SE CORNER OF CWA THIS AFTN. VII && .PRELIMINARY POINT TEMPS/POPS... SHV 85 63 83 64 / 10 10 20 20 MLU 84 61 85 61 / 10 10 10 10 DEQ 83 60 82 62 / 10 10 20 20 TXK 84 62 82 63 / 10 10 20 20 ELD 84 60 86 62 / 10 10 10 10 TYR 84 62 80 65 / 10 10 30 30 GGG 84 62 81 65 / 10 10 30 30 LFK 85 65 81 66 / 10 10 30 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 06/99/99
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
118 PM EDT MON MAY 4 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 449 AM EDT MON MAY 4 2015 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD SHALLOW TROUGH ACROSS SRN CANADA INTO THE NORTH CENTRAL CONUS. A SHORTWAVE TROUGH LIFTING NE THROUGH NRN ONTARIO WAS DRAGGING A COLD FRONT THROUGH ERN UPPER MICHIGAN. THE PCPN ASSOCIATED WITH THE FRONT AND 700-300 MB QVECTOR CONV AHEAD OF THE MID LEVEL TROUGH HAD MOVED SOUTH AND EAST OF THE CWA. BEHIND THE FRONT...DRIER AIR WAS QUICKLY MOVING INTO UPPER MICHIGAN...PER 00Z KINL SOUNDING...WITH DEWPOINTS DROPPING INTO THE 30S OVER THE NORTH AND WEST. IR LOOP SHOWED MID AND HIGH CLOUDS LINGERING OVER MOST OF UPPER MICHIGAN WITH CLEARING ONLY OVER THE FAR WEST. TODAY...AS HIGH PRES BUILDS FROM THE NRN PLAINS INTO THE WRN GREAT LAKES...EXPECT THE CLOUDS TO DEPART EARLY LEAVING MOSTLY SUNNY SKIES WITH ONLY FEW/SCT CU DEVELOPING. MIXING TO AROUND 5K FEET INLAND WITH 850 MB TEMPS AROUND 5C WILL SUPPORT HIGHS IN THE MID TO UPPER 60S. THE WEAK NRLY WINDS OFF OF LAKE SUPERIOR WILL KEEP READINGS IN THE 50S CLOSER TO THE SHORE. WITH AFTERNOON DEWPOINTS FALLING INTO THE MID TO UPPER 20S...INLAND RH VALUES WILL FALL OFF TO 20 TO 25 PCT. TONIGHT...HIGH PRES WILL DOMINATE KEEPING CONDITIONS DRY MON NIGHT THROUGH TUE. WITH PWATS DROPPING DOWN BELOW.25 INCH AND LIGHT WINDS EXPECTED UNDER THE SFC HIGH...MIN TEMPS NEAR FREEZING ARE EXPECTED AT THE TYPICAL INLAND COLD LOCATIONS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 330 AM EDT MON MAY 4 2015 TUESDAY...SFC HIGH PRESSURE ACROSS LAKE SUPERIOR AND UPPER MI AHEAD OF MID-LEVEL RIDGING OVER THE NORTHERN PLAINS WILL RESULT IN SUNNY SKIES...THOUGH A FEW HIGH CLOUDS MAY FILTER IN THE FROM SE DURING THE AFTERNOON. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...MODELS HAVE TRENDED DOWN A LITTLE BIT ON THE QPF FOR LATE TUE NIGHT INTO WED ALONG AN 850 HPA WARM FRONT/300-310K ISENTROPIC LIFT. WITH STOUT MID-LEVEL RIDGING MOVING OVER THE UPPER MS VALLEY AND OVERALL DEEPER MOISTURE AND LOW- LEVEL MOISTURE TRANSPORT REMAINING CONFINED TO THE WESTERN CWA...KEPT ONLY LOW CHANCE POPS FOR THE WEST HALF. PRECIP CHANCES DIMINISH TO LOW-END SLIGHT CHANCE ACROSS THE WEST WED NIGHT AS THE LOW-LEVEL WAA EXITS TO THE NE AND MID-LEVEL FORCING WELL SW OF THE REGION STRUGGLES TO WORK INTO THE RIDGE. THURSDAY THROUGH FRIDAY...DEEP TROUGHING MOVING ONTO THE PACIFIC NW LATE TODAY WILL HELP KICK A SLOW-MOVING MID-LEVEL TROUGH/LOW ACROSS THE SW STATES BY MID WEEK. THIS WILL CONSOLIDATE A BROAD SFC LOW ACROSS THE WESTERN STATES ON WED. THE LOW IS PROGGED TO TRACK NNE ACROSS THE NORTHERN PLAINS BEFORE BEGINNING TO TURN EASTWARD OVER WESTERN ONTARIO. IT REMAINS TO BE SEEN HOW WELL THE MID-LEVEL TROUGH CAN ERODE THE RIDGE OVER THE UPPER MS VALLEY AND UPPER GREAT LAKES BY THURSDAY. THE ECMWF IS THE MOST PROGRESSIVE WITH THE OVERALL PATTERN...WITH THE TROUGH AND SFC COLD FRONT CLEARING THE CWA BY FRIDAY EVENING. MEANWHILE...THE CANADIAN GEM IS QUITE SLOW...SENDING THE TROUGH WELL NORTH AND WASHING OUT THE COLD FRONT ACROSS THE CWA ON SATURDAY. THE GFS FALLS BETWEEN THESE TWO SOLUTIONS...BUT LEANS TOWARD THE ECMWF. THERE SHOULD BE ENOUGH MID-LEVEL ENERGY TO CHIP AWAY AT THE RIDGE...BUT LIKELY NOT AS FAST AS IS PROGGED BY THE ECMWF. HAVE THEREFORE CHOSEN TO FOLLOW A SOLUTION CLOSE TO THAT OF THE GFS. WITH ALL THAT TAKEN INTO ACCOUNT...SCATTERED SHOWERS AND SOME THUNDERSTORMS SHOULD PUSH INTO THE WESTERN CWA THURSDAY AFTERNOON...AND GRADUALLY SPREAD EASTWARD AS FORCING FROM THE MID- LEVEL WAVE WORKS OVER THE CWA. SCATTERED SHOWERS AND THUNDERSTORMS SHOULD THEN CONTINUE THROUGH MOST OF FRIDAY BEFORE THE COLD FRONT ENDS CHANCES ACROSS THE WEST FRIDAY EVENING. SATURDAY AND SUNDAY...AFTER A LULL IN PRECIP ON SATURDAY...A LARGE PORTION OF THE MAIN WESTERN TROUGH WILL TRACK ACROSS THE PLAINS AND BRING INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS THE CWA FOR SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 117 PM EDT MON MAY 4 2015 VFR CONDITIONS WILL CONTINUE AT ALL 3 TAF SITES THIS FCST PERIOD. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 449 AM EDT MON MAY 4 2015 FOG IS EXPECTED TO LINGER THIS MORNING OVER THE E HALF OF LAKE SUPERIOR BUT WILL DISSIPATE AS HIGH PRESSURE AND DRIER AIRS BUILDS OVER THE UPPER LAKES FROM THE W-NW TODAY. EXPECT THE HIGH TO DRIFT INTO SE ONTARIO LATER TUESDAY INTO WEDNESDAY...AS ANOTHER AREA OF HIGH PRESSURE MOVES INTO NW ONTARIO...AD A LOW DEVELOPS OVER THE PLAINS. A LOW PRESSURE CENTER WILL MOVE THROUGH THE NRN PLAINS ON THURSDAY WHILE THE ONTARIO HIGH DRIFTS ACROSS HUDSON BAY INTO QUEBEC. THE LOW WILL DRAG A TROUGH ACROSS THE UPPER GREAT LAKES REGION THURSDAY NIGHT THROUGH FRIDAY. ALTHOUGH SRLY WINDS WILL INCREASE FROM THU INTO THU NIGHT...WINDS ARE EXPECTED TO REMAIN AT OR BELOW 20 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KLUBER AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1253 PM EDT MON MAY 4 2015 .AVIATION... MAINLY MID CLOUDS LEFT BEHIND THIS MORNINGS LINE OF SHOWERS AND EMBEDDED THUNDERSTORMS. A COLD FRONT WILL BE SLOWLY WORKING THROUGH SOUTHEAST MICHIGAN THIS AFTERNOON/EARLY THIS EVENING...THUS THEIR REMAINS A LOW CHANCE OF SHOWER/THUNDERSTORM ACTIVITY...BUT AREAL COVERAGE AND CONFIDENCE PRECLUDES THE MENTION IN THE TAFS. A SHORT PERIOD OF LOWER CEILINGS ARE POSSIBLE WITH THE FROPA...AS WINDS SHIFT AROUND TO THE NORTHWEST...ALLOWING DRIER AIR TO FILTER IN. TONIGHT SHOULD BE DRY...WITH FRONTAL BOUNDARY RETURNING NORTH TOMORROW AS A WARM FRONT. IT APPEARS RAIN SHOULD AT LEAST REACH THE SOUTHERN TAF SITES (DTW/DET/YIP)...BUT CONFIDENCE IS AVERAGE. //DTW THRESHOLD PROBABILITIES... * LOW FOR CEILING AOB 5000FT THIS AFTERNOON AND TONIGHT...MEDIUM TOMORROW. * LOW FOR THUNDERSTORMS THIS AFTERNOON AND EVENING AND THEN AGAIN TOMORROW. && .PREV DISCUSSION...ISSUED 1027 AM EDT MON MAY 4 2015 UPDATE... MOISTURE AXIS (850-700 MB THETA-E RIDGE) WORKING THROUGH SOUTHEAST MICHIGAN THIS MORNING...GENERATING LINE OF SHOWERS/EMBEDDED THUNDER. AMOUNT OF RECOVERY BEHIND THIS BATCH OF SHOWERS WILL BE KEY THIS AFTERNOON...AS SURFACE COLD FRONT ADVANCES SOUTH THROUGH THE CWA. STILL...SURFACE DEW PTS WILL LIKELY BE HARD PRESSED TO REACH/EXCEED 60 DEGREES...AND CAPES WILL LIKELY BUILD TO AROUND 1000 J/KG WITH TEMPS IN THE 70S. PLANNING ON CARRYING SCATTERED/CHANCE POPS FOR THE AFTERNOON HOURS WITH THE LACK OF UPPER LEVEL SUPPORT...AS HRRR ALSO SHOWING LITTLE ACTIVITY. COULD SEE A SCENARIO WHERE COOLER WATERS OF LAKE HURON PROVIDE LITTLE BOOST TO THE COLD FRONT MOVING THROUGH THE THUMB REGION...AND WOULD NOT RULE OUT THE ENHANCED CONVERGENCE ALLOWING AN ISOLATED CELL TO APPROACH SEVERE LIMITS...AS FREEZING LEVELS ARE IDEAL...AND WIND FIELDS ARE MODERATE (25 TO 30 KNOTS OF 0-5KM BULK SHEAR). BUT AGAIN...THAT IS ASSUMING WE SUFFICIENTALY RECOVER...IF CLOUDS REMAIN LOCKED IN...THEN FORGET IT. PREV DISCUSSION...ISSUED 352 AM EDT MON MAY 4 2015 SHORT TERM... TODAY AND TONIGHT AFTER AN OUTSTANDING WEEKEND OF DRY AND WARM WEATHER...AN ACTIVE PRECIPITATION PATTERN WILL GET UNDERWAY TO START THE WEEK. BEGINNING THIS MORNING...SHOWERS AND A FEW THUNDERSTORMS WILL MARK THE LEADING EDGE OF INCREASED LOW LEVEL MOISTURE ADVANCING THROUGH LOWER MICHIGAN. MORNING COVERAGE WILL BE GREATEST FROM FLINT TO THE TRI CITIES AND NORTHERN THUMB BUT ALL AREAS WILL HAVE AT LEAST A CHANCE OF SHOWERS AS THE MOISTURE SURGE PROGRESSES THROUGH THE REGION. THE COLD FRONT APPROACHING FROM THE WEST WILL THEN TAKE OVER DURING THE AFTERNOON. THAT IS WHEN THE HIGHEST CONCENTRATION OF SHOWERS AND STORMS WILL SHIFT GENERALLY SOUTH OF THE INTERSTATE 69 CORRIDOR THROUGH EARLY EVENING. AFTERNOON THUNDERSTORM POTENTIAL WILL BE STRONGLY DEPENDENT ON RECOVERY OF SURFACE BASED INSTABILITY THAT WILL BE LIMITED BY MORNING CLOUDS AND PRECIPITATION. RADAR OBSERVATIONS INDICATE SHOWERS AND A FEW THUNDERSTORMS EXPANDING IN COVERAGE OVER SW LOWER MICHIGAN SINCE MIDNIGHT. THIS IS OCCURRING ON THE LEADING EDGE OF THE LOW LEVEL MOISTURE AXIS WITH A MODESTLY INCREASING LOW LEVEL JET...BOTH OF WHICH ARE GENERATING A TYPICAL PATTERN OF NOCTURNAL ELEVATED INSTABILITY. THE 00Z MODELS HAVE A REASONABLE HANDLE ON THIS SCENARIO JUDGING BY THETA-E AND WIND FIELDS IN THE 850-700 MB LAYER. PREFER THOSE THAT ARE MORE BULLISH ON THE MAINTENANCE OF MORNING QPF OVER SE MICHIGAN NOW THAT MOISTURE ADVECTION IS PROVING ADEQUATE TO GENERATE CONVECTION. FOR NOW...PLAN TO NUDGE MORNING POPS UP INTO THE CATEGORICAL RANGE IN THE TRI CITIES AND INTO HIGH LIKELY SOUTHWARD ALONG THE U.S. 23 CORRIDOR TO ACCOUNT FOR SOUTHWARD EXPANSION ALONG THE MOISTURE GRADIENT. THERE IS GOOD MODEL AGREEMENT INDICATING THE COLD FRONT IS ON PACE TO BE THROUGH THE TRI CITIES AND NORTHERN THUMB BY EARLY AFTERNOON. EXPECT IT WILL TAKE UNTIL THEN FOR BOUNDARY LAYER TEMPERATURE RECOVERY TO OCCUR ON THE HEELS OF THE MORNING SHOWERS AND CONVECTIVE CLOUD DEBRIS. THIS SUGGESTS LEANING THE FORECAST TOWARD THE LOWER END OF THE MODEL RANGE FOR SURFACE BASED CAPE. THE NAM CONTINUES TO ADVERTISE CAPE REACHING 1500-1800 J/KG SUBJECT TO SURFACE DEWPOINT RISING INTO THE LOWER 60S AS SURFACE TEMPERATURE RECOVERS INTO THE MID TO UPPER 70S. THE RAP AND GFS ALSO INDICATE SURFACE DEWPOINT REACHING THE LOWER 60S BUT PRODUCE CAPE CLOSER TO 1000 J/KG WITH MAIN DIFFERENCE BEING SHALLOWER MID LEVEL LAPSE RATES. THIS IS GENERALLY PREFERRED CONSIDERING THE WARM LARGE SCALE UPPER AIR PATTERN...ESPECIALLY FOR THIS TIME OF YEAR. THE ONE WILD CARD TO MONITOR IS THE HINT OF MCV DEVELOPMENT OVER THE MIDWEST THAT COULD HELP A FEW STORMS OVERACHIEVE. WITH THAT IN MIND...THE SPC OUTLOOK FOR MARGINAL LOOKS REASONABLE BEFORE THE FRONT SETTLES SOUTH OF THE OHIO BORDER BY MIDNIGHT. LONG TERM...TUESDAY THROUGH SUNDAY MID LEVEL WESTERLIES TAKE HOLD TUESDAY AND TUESDAY NIGHT ALONG THE NORTHERN PERIPHERY OF SLOWLY EXPANDING SOUTHEAST CONUS UPPER RIDGING. THIS POSITIONING WILL EFFECTIVELY ANCHOR THE SURFACE REFLECTION OF THE EXITING COLD FRONTAL BOUNDARY INVOF OF THE OH/MI BORDER DURING THIS TIME. CONTINUED CONVERGENCE ACROSS THE FRONTAL SLOPE AUGMENTED BY A COMBINATION OF BOTH LOW AMPLITUDE IMPULSES AND/OR REMNANT MCV ACTIVITY AND SOME RENEWED ISENTROPIC LIFT WILL SUPPORT AT LEAST A CHANCE FOR SHOWER DEVELOPMENT. THIS PATTERN PROVIDING THE USUAL CHALLENGES IN DEFINING BOTH POSSIBLE COVERAGE AND TIMING...SOME DEPENDENCE ON HOW NOCTURNAL CONVECTION EXPECTED TO BLOSSOM OVER THE MIDWEST TONIGHT EVENTUALLY SPILLS DOWNSTREAM. GREATER POTENTIAL WILL LIE TOWARD THE SOUTH GIVEN THE FRONTAL POSITIONING AND LESS INFLUENCE FROM DRIER AIR NOSING IN FROM THE NORTH. RIBBON OF HIGHEST THETA-E WILL RESIDE ALONG AND SOUTH OF THE BOUNDARY...BUT OVERALL MOISTURE QUALITY CERTAINLY REMAINS ADEQUATE /PW HOLDING AT 1.3"/. LOW LEVEL ANTICYCLONIC FLOW FILLING ACROSS NORTHERN LOWER MI WILL SUSTAIN A MORE STABLE LOW LEVEL EASTERLY FLOW LOCALLY. THIS WILL KEEP INSTABILITY AT A MINIMUM...CONFINED ABOVE A FIRM INVERSION NOW IN PLACE UP THROUGH 900 MB. THIS EASTERLY FLOW COMBINED WITH A HIGHER DEGREE OF CLOUD COVER AND PROSPECTS FOR SHOWERS TO DISRUPT THE HEATING CYCLE WILL CAP HIGHS IN THE LOWER AND MIDDLE 60S ON TUESDAY. UPPER RIDGE AXIS WILL MOVE ACROSS SE MICHIGAN WEDNESDAY AND WEDNESDAY NIGHT. A SLOWER LOW LEVEL RESPONSE WILL LIKELY RETAIN A LONGER RESIDENCE TIME OF EAST/SE FLOW LOCALLY...LEAVING THE FRONTAL SLOPE DRAPED OVER OR JUST TO THE SOUTHWEST FOR THE BULK OF THE DAYTIME PERIOD. 00Z MODEL GUIDANCE HOLDING WITH JUST VERY LIMITED PRECIPITATION POTENTIAL OWING TO BOTH THE DEGREE OF STABILITY/UPPER RIDGE POSITIONING AND LACK OF SHORTWAVE ENERGY/REMNANT CONVECTIVE DEBRIS TO PROVIDE AN ADDITIONAL FOCUS. CERTAINLY PLAUSIBLE A FEW SHOWERS EMERGE AS WEAK ASCENT PERSISTS ALONG THE ELEVATED FRONTAL SLAB /900-700 MB/...BUT CONFIDENCE REMAINS ON THE LOWER END AND WILL MAINTAIN A LIMITED MENTION AT THIS TIME. THE UPWARD ADJUSTMENT IN HEIGHTS AND GREATER PROSPECTS FOR SOME PEAKS OF SUN WILL NUDGE HIGHS UP A CATEGORY OR TWO RELATIVE TO TUESDAY. HIGHS UPPER 60S TO LOWER 70S. A PERIOD OF DEEPER SOUTHWEST FLOW FOR THE LATTER HALF OF THE WEEK...DICTATED BY HIGH AMPLITUDE TROUGHING ACROSS THE INTERMOUNTAIN WEST AND UPPER RIDGING EDGING TOWARD THE EAST COAST. THIS WILL PROVIDE A MORE NOTEWORTHY INCREASE IN THE TEMPERATURES FOR BOTH THURSDAY AND FRIDAY. HIGHS MAKING A RUN TOWARD THE LOWER 80S BY FRIDAY. WARM/DRY PROFILE WITH NEGLIGIBLE FORCING WILL MINIMIZE CONVECTIVE CHANCES ON THURSDAY. SIMILAR ENVIRONMENT ON FRIDAY PER 00Z GFS BUT ECMWF PROVIDES A PROGRESSIVE SOLUTION RUNNING A LEAD WAVE OVER THE RIDGE AND DRAGGING THE ATTENDANT COLD FRONT INTO THE REGION BY PEAK HEATING. LOWER END CHANCE POPS REMAIN APPROPRIATE TO HIGHLIGHT THE POTENTIAL AND UNCERTAINTY FOR THE NEXT ROUND OF SHOWERS/THUNDERSTORMS DURING THIS TIME WINDOW. MARINE... POTENTIAL FOR THUNDERSTORMS ACROSS ALL MARINE AREAS THROUGH TONIGHT AS A COLD FRONT MOVES ACROSS THE REGION. SOUTHWEST WINDS TODAY WILL SHIFT TO NORTHWESTERLY BY EVENING. LIGHT EASTERLY WINDS WILL THEN DEVELOP FOR TUESDAY AND WEDNESDAY AS HIGH PRESSURE BUILDS ACROSS THE NORTHERN GREAT LAKES. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....SF UPDATE.......SF SHORT TERM...BT LONG TERM....MR MARINE.......MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
126 PM CDT Mon May 4 2015 .SHORT TERM: (Today and Tonight) Issued at 330 AM CDT Mon May 4 2015 There are 2 main areas with precipitation potential this morning. The first is from southeast/east central MO eastward into IL where low-mid level warm advection has resulted in spotty showers within the last few hours. The GFS and recent runs of the HRRR suggest this potential will persist until around mid morning. The other area is across northeast MO/west central IL extending into parts of central MO. The frontal convection has in general become less organized with one area from eastern IA into northern IL and another cluster in NW MO. Both regions have generated a pre-frontal cold pool and outflow boundary, but its the western-most area in NW MO that bears the most watching. General movement has been to the southeast and some of the hi-res WRFs want to bring this cluster along with some additional development into north-central/central MO this morning. The current cluster is within a region of moisture convergence along the northern terminus of a 40+ kts southwesterly LLJ and weak elevated CAPE. It should encounter a less favorable environment as it moves southeast this morning, primarily after 12z, however forcing may be sufficient for scattered showers and thunderstorms within the area highlighted by the hi-res guidance. Otherwise clouds should thin across the entire area during the later half of the morning and into the early afternoon and when combined with the present WAA regime and temps aloft, this should result in another warm day with well above normal highs in the 80s. There are some discrepancies in the guidance on the southward position of the front this afternoon and evening with the RAP and ECMWF showing a bit more southward position into the northern part of the CWA by 00z, while the remainder of the models keep it near or just south of the MO/IA border. I think it will ooze south into the far northern part of the CWA by late afternoon. Present indications are that heating and continued low-level moistening late morning into afternoon will result in moderate instability along the frontal zone. Good low level convergence along the boundary combined with lift associated with a migrating short wave moving across southern IA/northern MO should result in extensive convective development during the later half of the afternoon spanning from KS across northern MO/southern IA into central IL. I am still thinking that the broad and veering southwesterly LLJ will maintain numerous thunderstorms/clusters during the evening with a decided eastward motion. Although the models suggest the front will shift slightly northward overnight I am not so sure this will happen with rain cooled air maintaining its position. However increased ridging aloft both in the low-mid levels suggest that the forecast of a northward shift in the convection overnight is reasonable. The only noticeable change to the pops tonight is to expand the area of slight chances southward a bit to I-70. The GFS and ECMWF QPFs are a bit far south and well into the warm sector and I would think the majority of the convection will reside along the front and northward into the cool air. Glass .LONG TERM: (Tuesday through Sunday) Issued at 330 AM CDT Mon May 4 2015 Not much has changed in thinking from 24 hours ago with respect to the Tuesday through weekend period. The front will make a decided shift northward on Tuesday as ridging aloft continues to build from the lower TN Valley into the upper MS Valley, while across southern sections of the CWA we continue to see the models generate some light QPF. I`m still not sold on it but will maintain low pops in the slight range given the uncertainty. Tuesday still looks to be another day of above normal temps with highs in the 80s. Flow aloft becomes more south-southwest on Wednesday and a lead impulse within this flow will traverse the western CWA prompting an increased threat of showers and thunderstorms across western MO into central MO. Flow aloft becomes southwesterly by Thursday and this regime persists into the weekend ahead of a upper trof/low migrating from the western U.S. and into the central U.S.. The threat of showers and thunderstorms Thursday into the weekend gradually ramps up and spreads west to east due to the active southwest flow aloft with embedded disturbances, moist unstable warm sector, and slowly encroaching cold front. Above normal temperatures should persist through the extended period. Glass && .AVIATION: (For the 18z TAFs through 18z Tuesday Afternoon) Issued at 100 PM CDT Mon May 4 2015 The cold front that approached the area last night has stalled today and is currently aligned from nthrn IL to SE IA to NW MO and then on into KS. This bndry is not expected to make much more addtnl progress to the SE today. Pesky -SHRAs have continued to drift across cntrl MO today with an occnl lightning strike. This activity should continue to slowly weaken as it works east this aftn. Another area of remnant SHRAs across cntrl IL will continue to move away from the area. An expanding area of mainly SHRAs with isld TSMS across ern NE and SW IA will continue to dvlp and move east this aftn and into the envg. This activity should be tied to the bndry which would keep the majority of the activity N of the terminals...but I do expect KUIN to be impacted tonight and possibly sooner. KUINs CIGs/VSBYs will be tied to the strength of the convection...but it is too early to try and pin that detail down attm. The bndry begins lifting back to the north after midnight taking the threat of precip with it. The only caveat is if the convection can get organized and push an outflow bndry SE...and then the question becomes timing and how far it makes it before dssptng. Either way Tuesday should be VFR. Specifics for KSTL: VFR fcst thru the prd as the nearby bndry should remain too far to the NW of the terminal to be of any concern. Diurnal cu has dvlpd once again with plenty of convective debris clouds slowly thinning thru the aftn. Winds will continue to have a shtrly component. The only caveat to the fcst is if convection along the bndry becomes organized and pushes an outflow bndry SE tonight...then the question becomes timing and how far SE it makes it before dssptng but not confident enough in this scenario to include attm. 2% && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1232 PM CDT MON MAY 4 2015 .UPDATE... ISSUED AT 1129 AM CDT MON MAY 4 2015 MULTIPLE SHORT-TERM UPDATES HAVE BEEN POSTED TO THE FCST. A CONVECTIVELY GENERATED VORTEX /MCV/ IS LIFTING NE ACROSS THE FCST AREA AND AN 88D LOOP SUGGESTS THE CENTER IS NEAR BELOIT KS. THERE EVEN APPEARS TO BE A SFC REFLECTION/LOW IN SFC PLOTS. A COUPLE NARROW BANDS OF TSTMS HAVE DEVELOPED OVER S-CNTRL NEB ALONG AND JUST E OF HWY 281. MOST OF THE SHWR/TSTM ACTIVITY IS IN THE NW SEMI-CIRCLE OF THIS CIRCULATION. MUCAPE IS 250 J/KG OR LESS WHICH IS ENOUGH FOR LIGHTNING STRIKES AND BRIEF HEAVY DOWNPOURS...BUT LITTLE ELSE. AS CLOUD COVER THINS THIS AFTERNOON...EXPECT MODEST DESTABILIZATION AND ADDITIONAL SCT COULD SHWRS/TSTMS REDEVELOP IN NARROW ARCS/BANDS. SEVERE: THE COOL FRONT THAT MOVED THRU SUN AFTERNOON/EVE EXTENDED SW-NE ACROSS KS...FROM GCK-RSL-FRI-STJ. DESTABLIZATION WILL BE GREATEST ALONG AND S OF THIS LINE AND THIS IS WHERE TSTM INITIATION WILL OCCUR...MAINLY S AND E OF THE FCST AREA. THE NRN FRINGE OF THE INSTABILITY WILL EXIST OVER N-CNTRL KS...WITH 1000-1500 J/KG OF MUCAPE. THERE WILL BE A FRONTAL INVERSION /CINH/ IN PLACE...BUT ENOUGH HEATING COULD ALLOW FOR A FEW STORMS TO DEVELOP ON THE COOL SIDE OF THE FRONT...WHERE SHEAR WOULD BE GREATER AND ALLOW FOR BETTER STORM ORGANIATION. ONE NEGATIVE FACTOR IS POOR MID-LVL LAPSE RATES. FCST CAPE PROFILES LOOK SKINNY...BUT IT IS DIFFICULT TO KNOW THE EXACT ENVIRONMENT SINCE MODEL CONVECTIVE SCHEMES ARE KICKING IN EARLY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 514 AM CDT MON MAY 4 2015 SIMILAR TO YESTERDAY...THE BIGGEST CHALLENGE WILL BE DETERMINING CHANCES AND TIMING OF SHOWERS/THUNDERSTORMS AS WELL AS THE POTENTIAL FOR STRONG STORMS. ANOTHER CHALLENGE WILL BE DETERMINING HIGH TEMPERATURES FOR TODAY. SYNOPTICALLY...WE CONTINUE THE SPLIT FLOW SCENARIO WHILE WE ARE BETWEEN JET STREAMS. A BROAD NEGATIVELY TILTED MEAN TROUGH IN THE WESTERN UNITED STATES NUDGES A LITTLE CLOSER AS A PERTURBATION A SURFACE BOUNDARY HAS STALLED OVER THE FAR SOUTHEASTERN CWA. A MID- LEVEL PERTURBATION WILL MOVE NORTHEAST OUT OF COLORADO/KANSAS INTO OUR AREA BY MID-DAY. THIS WILL LIKELY SPARK SOME THUNDERSTORM ACTIVITY NEAR AND NORTH OF THE STALLED FRONT. INSTABILITY COULD BE AS HIGH AS 2000 J/KG. MID TO UPPER LEVEL FLOW WILL BE WEAK. BULK SHEAR WILL BE WEAK AT MAYBE 20-30 KTS. THIS WILL BE ENOUGH FOR A MINIMAL SEVERE THREAT...AT LEAST IN OUR SOUTHERN CWA...AND AN ISOLATED TORNADO CAN NOT BE RULED OUT AS LOW-LEVEL SHEAR NEAR WILL BE ENHANCED NEAR AND JUST NORTH OF THE SURFACE BOUNDARY. HIGHS TODAY WILL BE TOUGH. THERE WILL BE A VERY LARGE TEMPERATURE GRADIENT AS THE SURFACE FRONT REMAINS STATIONARY OVER THE SOUTHERN CWA. THERE SHOULD BE PLENTY OF SKY COVER AS MODELS INDICATE AN EXTENSIVE SHIELD OF STRATUS DEVELOPING. TEMPERATURES NORTH OF THE BOUNDARY PROBABLY WILL NOT MAKE IT VERY FAR BECAUSE OF THIS AND HAVE SIDED TOWARD COOLER THAN GUIDANCE NUMBERS FOR HIGHS. WE MAY HAVE A HARD TIME BREAKING 60 IN SOME PLACES. I DECIDED TO GO WITH A BLEND OF THE HI RES NMM AND THE RAP FOR HIGHS...AS THESE MODELS HAVE DONE QUITE WELL LATELY. WENT WITH THE FAIRLY DEPENDABLE SUPERBLEND FOR LOWS TONIGHT. WE COULD ALSO GET SOME DECENT GUSTS TODAY NORTH OF THE BOUNDARY AS THE SURFACE PRESSURE GRADIENT WILL BE A BIT TIGHT. I WENT WITH CONSRAW WIND GUSTS FOR TODAY...WHICH IS GREATER THAN THE STANDARD WIND GUST ALGORITHM. DETERMINING CHANCES OF PRECIPITATION WAS BASED ON ENSEMBLE DATA AS WELL AS SUPERBLEND TRENDS. CONFIDENCE HAS NOT BEEN HIGH FOR CHANCES OF PRECIPITATION AND CONTINUES TO BE LOW FOR TODAY AND TONIGHT. WITH THE AFOREMENTIONED PERTURBATION FOR TODAY AND A BIT OF A LOW-LEVEL JET TONIGHT...ALONG WITH THE BOUNDARY SHIFTING NORTH TONIGHT...WE WILL HAVE A DECENT SHOT AT PRECIPITATION AT ALMOST ANY POINT DURING THE SHORT TERM. ANY THREAT OF STRONG TO SEVERE THUNDERSTORMS SHOULD REMAIN PRIMARILY IN THE AFTERNOON AND EVENING. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 514 AM CDT MON MAY 4 2015 EXPECT UNSETTLED WEATHER THROUGH THE WEEK. THE MAIN WEATHER FEATURE WILL BE AN UPPER LEVEL LOW THAT MOVES FROM THE CENTRAL ROCKIES INTO THE CENTRAL PLAINS AND OPENS THE WAVE AS IT MOVES TO THE NORTHEAST. ANOTHER UPPER LEVEL LOW MOVES INTO THE SOUTHWEST CONUS LATER IN THE WEEK. ON TUESDAY THE UPPER LOW IS STILL IN THE ROCKIES AND A WAVE MOVES INTO THE PLAINS AHEAD OF THE UPPER LOW. THE BEST CHANCE FOR THUNDERSTORMS WILL BE IN THE WESTERN PART OF THE AREA CLOSER TO THE UPPER WAVE. BY TUESDAY NIGHT THE WAVE MOVES ONTO THE PLAINS AND STARTS TO OPEN. THE THUNDERSTORMS SHOULD BE ACROSS THE ENTIRE AREA. WEDNESDAY INTO WEDNESDAY NIGHT THE UPPER WAVE IS NEAREST TO THE FORECAST AREA. THIS LOOKS TO BE SOME OF THE BEST CHANCES FOR THUNDERSTORMS. DURING THE AFTERNOON AND EVENING HOURS...THE MUCAPE INCREASES TO OVER 1500 J/KG AND SOME OF THESE STORMS COULD BE STRONG TO SEVERE. THE INITIAL UPPER WAVE MOVES TO THE NORTH ON THURSDAY AND EVEN THOUGH THERE COULD BE SOME SHOWERS AND THUNDERSTORMS AROUND...THE CHANCES WILL BE A LITTLE LESS THAN BEFORE. BY THURSDAY NIGHT THE NEXT UPPER LOW IN THE SOUTHWEST CONUS AND THE FIRST WAVE FROM THIS WAVE STARTS TO AFFECT THE AREA THURSDAY NIGHT INTO FRIDAY. FRIDAY NIGHT INTO SATURDAY THE UPPER LOW CONTINUES TO DRIFT TO THE EAST AND UPPER LEVEL WAVES CONTINUE TO MOVE INTO THE AREA...AND AS THE UPPER LOW MOVES INTO THE PLAINS SATURDAY NIGHT INTO SUNDAY THERE CONTINUES TO BE CHANCES FOR THUNDERSTORMS. TEMPERATURES THROUGH THE PERIOD WILL BE AT LEAST SOMEWHAT VARIABLE. TUESDAY THROUGH THURSDAY WILL BE WARM. THEN A WEAK COLD FRONT MOVES THROUGH THE AREA THURSDAY AFTERNOON AND EVENING BRINGING COOLER TEMPERATURES FOR FRIDAY. SATURDAY AND SUNDAY WILL REMAIN A LITTLE COOLER BUT STILL AROUND OR EVEN ABOVE NORMAL TEMPERATURES ARE EXPECTED. && .AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z TUE AFTERNOON) ISSUED AT 1231 PM CDT MON MAY 4 2015 THIS AFTERNOON: VARIABLE CIGS BETWEEN MVFR AND VFR WITH IFR VSBYS IN SHWRS/TSTMS POSSIBLE. NE WINDS 10-15 KTS. CONFIDENCE: LOW DUE TO UNCERTAINTY ON CIGS AND OCCURRENCE/TIMING OF SHWRS/TSTMS. TONIGHT: MVFR STRATUS CIGS SHOULD INVADE AND DEGRADE TO IFR AS WARM FRONT LIFTS N. A PERIOD OF MVFR OR IFR VSBYS POSSIBLE IN SHWRS AND POSSIBLE THUNDER. THEREAFTER...MVFR VSBYS POSSIBLE IN PATCHY FOG AFTER 09Z. NE WINDS DIMINISH AND SHIFT TO SE. CONFIDENCE: LOW ON ARRIVAL TIME OF STRATUS AND CIG CHANGES. TUE THRU 18Z: IFR STRATUS/PATCHY MVFR FOG LIFTS TO MVFR BY 15Z. SE WINDS INCREASE 10-15 KTS. CONFIDENCE: LOW && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HALBLAUB SHORT TERM...HEINLEIN LONG TERM...JCB AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1129 AM CDT MON MAY 4 2015 .UPDATE... ISSUED AT 1129 AM CDT MON MAY 4 2015 MULTIPLE SHORT-TERM UPDATES HAVE BEEN POSTED TO THE FCST. A CONVECTIVELY GENERATED VORTEX /MCV/ IS LIFTING NE ACROSS THE FCST AREA AND AN 88D LOOP SUGGESTS THE CENTER IS NEAR BELOIT KS. THERE EVEN APPEARS TO BE A SFC REFLECTION/LOW IN SFC PLOTS. A COUPLE NARROW BANDS OF TSTMS HAVE DEVELOPED OVER S-CNTRL NEB ALONG AND JUST E OF HWY 281. MOST OF THE SHWR/TSTM ACTIVITY IS IN THE NW SEMI-CIRCLE OF THIS CIRCULATION. MUCAPE IS 250 J/KG OR LESS WHICH IS ENOUGH FOR LIGHTNING STRIKES AND BRIEF HEAVY DOWNPOURS...BUT LITTLE ELSE. AS CLOUD COVER THINS THIS AFTERNOON...EXPECT MODEST DESTABILIZATION AND ADDITIONAL SCT COULD SHWRS/TSTMS REDEVELOP IN NARROW ARCS/BANDS. SEVERE: THE COOL FRONT THAT MOVED THRU SUN AFTERNOON/EVE EXTENDED SW-NE ACROSS KS...FROM GCK-RSL-FRI-STJ. DESTABLIZATION WILL BE GREATEST ALONG AND S OF THIS LINE AND THIS IS WHERE TSTM INITIATION WILL OCCUR...MAINLY S AND E OF THE FCST AREA. THE NRN FRINGE OF THE INSTABILITY WILL EXIST OVER N-CNTRL KS...WITH 1000-1500 J/KG OF MUCAPE. THERE WILL BE A FRONTAL INVERSION /CINH/ IN PLACE...BUT ENOUGH HEATING COULD ALLOW FOR A FEW STORMS TO DEVELOP ON THE COOL SIDE OF THE FRONT...WHERE SHEAR WOULD BE GREATER AND ALLOW FOR BETTER STORM ORGANIATION. ONE NEGATIVE FACTOR IS POOR MID-LVL LAPSE RATES. FCST CAPE PROFILES LOOK SKINNY...BUT IT IS DIFFICULT TO KNOW THE EXACT ENVIRONMENT SINCE MODEL CONVECTIVE SCHEMES ARE KICKING IN EARLY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 514 AM CDT MON MAY 4 2015 SIMILAR TO YESTERDAY...THE BIGGEST CHALLENGE WILL BE DETERMINING CHANCES AND TIMING OF SHOWERS/THUNDERSTORMS AS WELL AS THE POTENTIAL FOR STRONG STORMS. ANOTHER CHALLENGE WILL BE DETERMINING HIGH TEMPERATURES FOR TODAY. SYNOPTICALLY...WE CONTINUE THE SPLIT FLOW SCENARIO WHILE WE ARE BETWEEN JET STREAMS. A BROAD NEGATIVELY TILTED MEAN TROUGH IN THE WESTERN UNITED STATES NUDGES A LITTLE CLOSER AS A PERTURBATION A SURFACE BOUNDARY HAS STALLED OVER THE FAR SOUTHEASTERN CWA. A MID- LEVEL PERTURBATION WILL MOVE NORTHEAST OUT OF COLORADO/KANSAS INTO OUR AREA BY MID-DAY. THIS WILL LIKELY SPARK SOME THUNDERSTORM ACTIVITY NEAR AND NORTH OF THE STALLED FRONT. INSTABILITY COULD BE AS HIGH AS 2000 J/KG. MID TO UPPER LEVEL FLOW WILL BE WEAK. BULK SHEAR WILL BE WEAK AT MAYBE 20-30 KTS. THIS WILL BE ENOUGH FOR A MINIMAL SEVERE THREAT...AT LEAST IN OUR SOUTHERN CWA...AND AN ISOLATED TORNADO CAN NOT BE RULED OUT AS LOW-LEVEL SHEAR NEAR WILL BE ENHANCED NEAR AND JUST NORTH OF THE SURFACE BOUNDARY. HIGHS TODAY WILL BE TOUGH. THERE WILL BE A VERY LARGE TEMPERATURE GRADIENT AS THE SURFACE FRONT REMAINS STATIONARY OVER THE SOUTHERN CWA. THERE SHOULD BE PLENTY OF SKY COVER AS MODELS INDICATE AN EXTENSIVE SHIELD OF STRATUS DEVELOPING. TEMPERATURES NORTH OF THE BOUNDARY PROBABLY WILL NOT MAKE IT VERY FAR BECAUSE OF THIS AND HAVE SIDED TOWARD COOLER THAN GUIDANCE NUMBERS FOR HIGHS. WE MAY HAVE A HARD TIME BREAKING 60 IN SOME PLACES. I DECIDED TO GO WITH A BLEND OF THE HI RES NMM AND THE RAP FOR HIGHS...AS THESE MODELS HAVE DONE QUITE WELL LATELY. WENT WITH THE FAIRLY DEPENDABLE SUPERBLEND FOR LOWS TONIGHT. WE COULD ALSO GET SOME DECENT GUSTS TODAY NORTH OF THE BOUNDARY AS THE SURFACE PRESSURE GRADIENT WILL BE A BIT TIGHT. I WENT WITH CONSRAW WIND GUSTS FOR TODAY...WHICH IS GREATER THAN THE STANDARD WIND GUST ALGORITHM. DETERMINING CHANCES OF PRECIPITATION WAS BASED ON ENSEMBLE DATA AS WELL AS SUPERBLEND TRENDS. CONFIDENCE HAS NOT BEEN HIGH FOR CHANCES OF PRECIPITATION AND CONTINUES TO BE LOW FOR TODAY AND TONIGHT. WITH THE AFOREMENTIONED PERTURBATION FOR TODAY AND A BIT OF A LOW-LEVEL JET TONIGHT...ALONG WITH THE BOUNDARY SHIFTING NORTH TONIGHT...WE WILL HAVE A DECENT SHOT AT PRECIPITATION AT ALMOST ANY POINT DURING THE SHORT TERM. ANY THREAT OF STRONG TO SEVERE THUNDERSTORMS SHOULD REMAIN PRIMARILY IN THE AFTERNOON AND EVENING. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 514 AM CDT MON MAY 4 2015 EXPECT UNSETTLED WEATHER THROUGH THE WEEK. THE MAIN WEATHER FEATURE WILL BE AN UPPER LEVEL LOW THAT MOVES FROM THE CENTRAL ROCKIES INTO THE CENTRAL PLAINS AND OPENS THE WAVE AS IT MOVES TO THE NORTHEAST. ANOTHER UPPER LEVEL LOW MOVES INTO THE SOUTHWEST CONUS LATER IN THE WEEK. ON TUESDAY THE UPPER LOW IS STILL IN THE ROCKIES AND A WAVE MOVES INTO THE PLAINS AHEAD OF THE UPPER LOW. THE BEST CHANCE FOR THUNDERSTORMS WILL BE IN THE WESTERN PART OF THE AREA CLOSER TO THE UPPER WAVE. BY TUESDAY NIGHT THE WAVE MOVES ONTO THE PLAINS AND STARTS TO OPEN. THE THUNDERSTORMS SHOULD BE ACROSS THE ENTIRE AREA. WEDNESDAY INTO WEDNESDAY NIGHT THE UPPER WAVE IS NEAREST TO THE FORECAST AREA. THIS LOOKS TO BE SOME OF THE BEST CHANCES FOR THUNDERSTORMS. DURING THE AFTERNOON AND EVENING HOURS...THE MUCAPE INCREASES TO OVER 1500 J/KG AND SOME OF THESE STORMS COULD BE STRONG TO SEVERE. THE INITIAL UPPER WAVE MOVES TO THE NORTH ON THURSDAY AND EVEN THOUGH THERE COULD BE SOME SHOWERS AND THUNDERSTORMS AROUND...THE CHANCES WILL BE A LITTLE LESS THAN BEFORE. BY THURSDAY NIGHT THE NEXT UPPER LOW IN THE SOUTHWEST CONUS AND THE FIRST WAVE FROM THIS WAVE STARTS TO AFFECT THE AREA THURSDAY NIGHT INTO FRIDAY. FRIDAY NIGHT INTO SATURDAY THE UPPER LOW CONTINUES TO DRIFT TO THE EAST AND UPPER LEVEL WAVES CONTINUE TO MOVE INTO THE AREA...AND AS THE UPPER LOW MOVES INTO THE PLAINS SATURDAY NIGHT INTO SUNDAY THERE CONTINUES TO BE CHANCES FOR THUNDERSTORMS. TEMPERATURES THROUGH THE PERIOD WILL BE AT LEAST SOMEWHAT VARIABLE. TUESDAY THROUGH THURSDAY WILL BE WARM. THEN A WEAK COLD FRONT MOVES THROUGH THE AREA THURSDAY AFTERNOON AND EVENING BRINGING COOLER TEMPERATURES FOR FRIDAY. SATURDAY AND SUNDAY WILL REMAIN A LITTLE COOLER BUT STILL AROUND OR EVEN ABOVE NORMAL TEMPERATURES ARE EXPECTED. && .AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z TUE MORNING) ISSUED AT 548 AM CDT MON MAY 4 2015 AS A FRONT STALLS WELL SOUTH OF THE TERMINALS...A STRATUS DECK IS EXPECTED TO CONTINUE DEVELOPING AND SOCK US IN WITH SKY COVER. CONFIDENCE IS NOT AS HIGH AS TO HOW QUICKLY THIS DECK WILL LOWER. THERE COULD BE SOME ELEVATED THUNDERSTORMS...ESPECIALLY TOWARD THIS AFTERNOON/EVENING...BUT COVERAGE IS UNCERTAIN. VISIBILITY COULD BE SIGNIFICANTLY LESS IN A THUNDERSTORM...BUT SINCE PREDICTABILITY IS SO LOW...ANYTHING SPECIFIC HAS BEEN LEFT OUT OF THIS FORECAST. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HALBLAUB SHORT TERM...HEINLEIN LONG TERM...JCB AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
323 PM EDT MON MAY 4 2015 .SYNOPSIS... HIGH PRESSURE EXTENDING INTO THE AREA WILL CONTINUE TO DRIFT FARTHER OFFSHORE INTO MID-WEEK...PROVIDING SEASONABLE MAY WEATHER. A COASTAL LOW IS EXPECTED TO FORM IN THE BAHAMAS ON WEDNESDAY...DRIFT NORTH THEN MEANDER ALONG THE SOUTHEAST COAST FROM THURSDAY INTO NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM MONDAY...FIELD OF SHALLOW CU HAS DEVELOPED IN WEST OF THE SEA BREEZE THIS AFTERNOON. THIS CLOUD COVER WILL DISSIPATE QUICKLY AFTER SUNSET AND LIGHT S-SE WINDS WILL BECOME LIGHT AND VARIABLE BEFORE LIKELY DECOUPLING. THIS WILL BE A GOOD SETUP FOR RADIATIONAL COOLING AND TEMPS SHOULD FALL INTO THE MID 50S MOST LOCATIONS. SOME PATCHY FOG WILL BE POSSIBLE IN THE FEW HOURS BEFORE SUNRISE...ESPECIALLY INLAND WHERE THE TEMP-DEWPOINT DEPRESSION WILL BE SMALLEST. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...EARLY SUMMER PATTERN WITH BERMUDA-LIKE HIGH CENTERED OFFSHORE...PROVIDING A BALMY EARLY MAY CIRCULATION OF AIR CLIMATOLOGICALLY INDICATIVE OF THE SEASON. MODERATE CUMULUS BUILD-UPS SEEMS LIKELY DURING THE AFTERNOON NEAR AND WEST OF THE THE AFTERNOON SEA-BREEZE...BUT ARID AIR ABOVE 10 THOUSAND FEET THROUGH WED AFTERNOON WILL KEEP MEASURABLE RAIN PROBABILITIES BELOW MENTIONABLE LEVELS. MAXIMUMS EITHER SIDE OF 80 DEG WARMEST OVER THE INTERIOR...AND MINIMUMS UPPER 50S TO LOW 60S EARLY WED AND 60-65 EARLY THU. A COASTAL LOW APPROACHING FROM THE SOUTH WILL BRING A SLIGHT CHANCE OF RAIN SHOWERS FAVORED ALONG THE COAST WED NIGHT INTO EARLY THURSDAY...AS LOW-LEVEL WIND DIRECTION AND WINDSPEED CONVERGENCE INCREASES OFFSHORE. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 3 PM MONDAY...ALL EYES REMAIN ON A LOW PRESSURE SYSTEM WHICH LOOKS LIKELY TO DEVELOP AND STRENGTHEN OFF THE SOUTHEAST COAST LATE THIS WEEK. NHC HAS ISSUED A SECOND SPECIAL TROPICAL WEATHER OUTLOOK TO ADDRESS THIS POTENTIAL...AND WHILE IT IS BECOMING MORE LIKELY A SYSTEM WILL DEVELOP...THERE IS STILL VERY LITTLE CONFIDENCE INTO HOW IT WILL MOVE ONCE FORMING. AN AREA OF MOISTURE ALREADY EVIDENT ACROSS THE CARIBBEAN/BAHAMAS TODAY WILL CONSOLIDATE AND LIFT SLOWLY NORTH TO OFF THE GA/SC COAST AT THE START OF THE EXTENDED. INITIALLY...THIS SYSTEM WILL FEED OF BAROCLINICITY AS AN ET-CYCLONE...BUT GUIDANCE SUGGESTS IT WILL TRANSITION TO A WARM CORE SYSTEM BY LATE WEEK AND POSSIBLY TAKE ON TROPICAL OR SUB-TROPICAL CHARACTERISTICS. THIS IS IMPORTANT BECAUSE THE ENVIRONMENT IS NOT ENTIRELY FAVORABLE FOR BAROTROPIC (WITHOUT TEMPERATURE GRADIENTS) STRENGTHENING THANKS TO WEAK DIFFLUENCE ALMOST EXCLUSIVELY ON THE EAST SIDE...AND WATER TEMPS WELL BELOW THE 80F THRESHOLD ONCE YOU GET OUTSIDE THE GULF STREAM. THIS SUGGESTS THAT A COMBINATION OF BAROTROPIC AND BAROCLINIC FEATURES WILL DETERMINE THE STRENGTH...HENCE THE LIKELY HYBRID-LOW. THE GUIDANCE STILL DIVERGES CONSIDERABLY ON THE LOW TRACK THANKS TO WEAK STEERING FLOW...BUT AS MENTIONED BY THE PREVIOUS FORECASTER...A TRACK DUE NORTH SEEMS IMPOSSIBLE WITH THE UPPER RIDGE IN THAT DIRECTION. THUS...A RETROGRADING W OR SW TRACK IS MOST PLAUSIBLE AND SEEMS TO BE SUPPORTED BY ENSEMBLES. STILL...THIS CREATES A VERY TRICKY FORECAST WITH A MEANDERING AND POSSIBLY STRENGTHENING LOW FOR SEVERAL DAYS OFF THE COAST. THE 12Z GFS BRINGS A PRETTY STRONG LOW INTO CENTRAL SC...BUT THIS IS A NEW SOLUTION FROM EVEN THE LAST RUN WHICH BROUGHT IT INTO THE GA COAST. THE ECMWF CONTINUES TO KEEP THE SYSTEM SPINNING JUST OFFSHORE INTO THE WKND. WHILE IT IS IMPOSSIBLE TO DETERMINE WITH ANY SPECIFICITY THE TRACK AT THIS TIME RANGE...WILL CONTINUE TO SHOW UNSETTLED WEATHER THU-SUN WITH THE BEST CHANCE FOR RAIN/WIND BEING LATE THURSDAY INTO SATURDAY. ALTHOUGH THE SYSTEM SHOULD BEGIN TO WEAKEN THEREAFTER...CONTINUED SCHC/LOW CHC POP IS WARRANTED RIGHT THROUGH THE END OF THE PERIOD BEFORE A TROUGH APPROACHES FOR EARLY NEXT WEEK WHICH WILL ACT TO FINALLY KICK OUT THE LOW. TEMPS THROUGH THE PERIOD SHOULD BE ABOVE CLIMO...BUT OF COURSE ANY SIGNIFICANT RAIN/CLOUDS COULD HINDER WARMING AND WILL ALSO BE DEPENDENT ON THIS LOW TRACK. ADDITIONALLY...E/NE WINDS OFF COOL SHELF WATERS WILL KEEP THE COASTAL AREAS MUCH COOLER THAN WELL INLAND...SO A LARGE TEMP GRADIENT ACROSS THE CWA IS POSSIBLE EACH AFTN THROUGH THE PERIOD. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... AS OF 18Z...THE ONLY REAL CONCERN IS THE CONVECTIVE FIELD THAT LOOKS FAIRLY HEALTHY. HRRR STILL SHOWING A FEW SHOWERS DEVELOPING THIS AFTERNOON AS DOES THE GFS. WITH COASTAL TERMINALS NOW FIRMLY IN THE SEA BREEZE SHADOW...FEEL ANY ACTIVITY WILL NOT MAKE IT INTO THE INLAND TERMINALS. INCREASED THE MVFR FOG FOR CRE AND FLO LATE TONIGHT BASED ON THE LATEST NUMERICAL GUIDANCE...OTHERWISE VFR THROUGH THE PERIOD. EXTENDED OUTLOOK...PRE-DAWN MORNING FOG IS POSSIBLE EACH DAY THAT COULD RESULT IN MVFR/IFR CONDITIONS. UNSETTLED WEATHER THURSDAY NIGHT THROUGH SATURDAY WITH A SUBTROPICAL LOW. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM MONDAY...ISOLATED SHOWERS 10-20 NM OFF THE CAPE FEAR COAST HAVE STRUGGLED TO SURVIVE AS THEY ENCROACH ON THE RELATIVELY COOL SHELF WATERS AND ENCOUNTER SOME DOWNWARD MOTION RESULTING FROM THE SEA BREEZE. IF DISSIPATION TREND CONTINUES WILL PROBABLY NOT INCLUDE ANY POP FOR THE LATE AFTERNOON. OTHERWISE...SE FLOW WILL PERSIST OVERNIGHT AROUND SURFACE HIGH PRESSURE WHICH WILL LINGER OFF THE NC COAST OVERNIGHT. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...MANAGEABLE MARINE CONDITIONS MUCH OF THE PERIOD WITH INCREASING SEA HEIGHTS MAINLY LATE WEDNESDAY AS OFFSHORE SE-E WINDS BEGIN TO RAMP UP IN RESPONSE TO A BAHAMA COASTAL LOW DRIFTING NORTH. OTHERWISE...BERMUDA HIGH LIKE WEATHER WITH 2-3 FOOT SEAS AND AN INCREASE IN WIND GUSTS NEAR SHORE IN THE AFTERNOON TO EARLY EVENING DUE TO THE SEA BREEZE CIRCULATION. NO TSTMS EXPECTED THIS PERIOD...BUT SEAS MAY INCREASE TO 4-5 FT LATE WEDNESDAY NIGHT ACCOMPANIED BY INCREASING MARINE SHOWERS. LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 3 PM MONDAY...POTENTIAL CONTINUES FOR AN EXTENDED PERIOD OF POOR MARINE CONDITIONS THANKS TO A LOW PRESSURE SYSTEM THAT IS FORECAST TO DEVELOP AND POTENTIALLY TAKE ON TROPICAL CHARACTERISTICS THU-SAT. THERE IS STILL CONSIDERABLE UNCERTAINTY INTO THE STRENGTH AND TRACK OF THIS LOW...BUT IT LOOKS LIKELY THAT A SYSTEM WILL DEVELOP AND THEN MEANDER IN THE AREA THROUGH THE PERIOD. ATTM...IT APPEARS THE BEST COURSE OF ACTION IS A BLEND OF GUIDANCE...AND THIS CREATES E/NE WINDS OF 15-20 KTS THU/FRI...BEFORE EASING SATURDAY...HOPEFULLY. THIS EXTENDED PERIOD OF E/NE FETCH COMBINED WITH SWELL GENERATION FROM THE LOW PRESSURE...WILL DRIVE SEAS UP TO 4-8 FT THU AND FRI...BEFORE FALLING ON SATURDAY. OF COURSE THIS CAN CHANGE...AND THERE IS POTENTIAL FOR MUCH HIGHER SEAS AS THE WNAWAVE IS SHOWING 16 FT JUST OUTSIDE OF THE COASTAL WATERS FRIDAY. EITHER WAY...A LONG- DURATION STRONG SMALL CRAFT ADVISORY IS BECOMING MORE LIKELY FOR MUCH OF THE PERIOD. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...8 NEAR TERM...CRM SHORT TERM...MJC LONG TERM...JDW AVIATION...SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
122 PM EDT MON MAY 4 2015 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO DRIFT SLOWLY OFFSHORE EARLY TO MID-WEEK...PROVIDING SUNSHINE AND SEASONABLE MAY TEMPERATURES. A COASTAL LOW IS EXPECTED TO FORM IN THE BAHAMAS MID-WEEK...AND MEANDER ALONG THE SOUTHEAST COAST THROUGH THE END OF THE WEEK AND INTO NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM MONDAY...THE ATMOSPHERIC COLUMN IS RELATIVELY DRY OVERALL...HOWEVER 12Z SOUNDINGS FROM MHX AND CHS DO SHOW A LAYER OR MOISTURE JUST BELOW 700 MB. THIS MOISTURE IS EVIDENT IN VISIBLE SATELLITE IMAGERY AS A LAYER OF SCATTERED CLOUDS MOVING SSW AROUND H7-H8 HIGH PRESSURE CENTERED OVER CLT. WEAK MID-LEVEL TROFFINESS WILL SLIDE ACROSS THE AREA THIS AFTERNOON WHILE MODEST LOW- LEVEL RETURN FLOW SETS UP AROUND OFFSHORE SURFACE HIGH. HRRR INDICATES SOME POTENTIAL FOR LIGHT SHOWERS INLAND BY EARLY AFTERNOON AHEAD OF THE SEA BREEZE...BUT MOISTURE WILL BE THE LIMITING FACTOR. DO NOT PLAN TO ADD POPS TO THE FORECAST AT THIS TIME BUT CAN NOT RULE OUT A FEW BRIEF...LIGHT SHOWERS ACROSS THE WESTERN 2/3 OF THE CWA. NO CHANGE NEEDED TO MAX TEMP FORECAST... WITH AN EXPECTED RANGE OF MID-UPPER 70S AT THE BEACHES TO LOW 80S INLAND. CONTINUED ON SHORE FLOW TONIGHT AROUND OFFSHORE HIGH WILL SUPPORT A SLOW RISE IN DEWPOINTS AFTER A DIURNAL DROP THIS AFTERNOON IN DEEPER MIXING. THIS WILL KEEP OVERNIGHT LOWS A FEW DEGREES HIGHER THAN LAST NIGHT...BUT STILL DOWN TO 55 TO 60 MOST PLACES WITH IDEAL RADIATIONAL COOLING CONDITIONS UNDER CLEAR SKIES AND NEAR CALM WINDS. MAY SEE SOME PATCHY SHALLOW GROUND FOG AGAIN TONIGHT AS TEMPS DROP OUT BUT COLUMN WILL BE VERY DRY ABOVE THE SURFACE. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...BERMUDA HIGH ON TUESDAY WILL RETREAT WEDNESDAY AHEAD OF DISTURBANCE EMERGING FROM THE CARIBBEAN AND THE BAHAMAS. MID LEVEL RIDGING IN PLACE ABOVE THE BERMUDA HIGH TUE WILL MAINTAIN WARM AND DRY CONDITIONS ACROSS THE AREA WITH ONLY PATCHES OF SHALLOW AFTERNOON CU. ONSHORE FLOW WILL CONTINUE KEEPING TEMPS NEAR THE COAST AROUND CLIMO WHILE INLAND AREAS WARM UP A BIT. SECOND HALF OF THE PERIOD STARTS TO GET INTERESTING AS THE SYSTEM EMERGING FROM THE BAHAMAS WILL TRY AND COALESCE INTO A WELL DEFINED LOW. THE GOING WILL INITIALLY BE SLOW AND THE LACK OF STEERING FLOW ALOFT IS LIKELY TO KEEP THE SYSTEM SOUTH OF THE AREA THROUGH THE END OF THE PERIOD. STILL A LOT OF UNCERTAINTY REGARDING THIS SYSTEM AND WHILE IT MAY LEAD TO AN INCREASE IN CLOUD COVER...ESPECIALLY ALONG THE COAST WED NIGHT...DO NOT THINK IT WOULD DIRECTLY AFFECT THE REGION BEFORE THE END OF THE PERIOD. THUS WILL MAINTAIN THE DRY FORECAST WITH HIGHS AROUND CLIMO AND LOWS A BIT ABOVE CLIMO. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 3 AM MONDAY...LONG TERM PERIOD WILL BE DOMINATED BY THE LOW EVOLVING OFF THE SOUTHEAST COAST MID TO LATE WEEK. GUIDANCE CONTINUES TO STRUGGLE WITH THIS SYSTEM...MAINLY DUE TO THE LACK OF ANY REAL STEERING FLOW ALOFT. HOWEVER SOME SOLUTIONS SEEM HARD TO BUY. FOR INSTANCE THE LOW DEEPENING AND MOVING UP THE COAST SEEMS THE LEAST LIKELY OUTCOME GIVEN THE 5H RIDGING TO THE NORTH. DO THINK THE LOW COULD GRADUALLY STRENGTHEN THROUGH THE PERIOD. ALTHOUGH THE WATER TEMPS WITHIN THE GULF STREAM ARE AROUND 80 AND SHEAR SHOULD BE WEAK TO NONEXISTENT THERE ARE SEVERAL FACTORS THAT WOULD LIMIT STRENGTHENING. A LACK OF DIFFLUENCE ALOFT EARLY IN THE PERIOD AND THE LARGE SWATH OF SEA SURFACE TEMPS OUTSIDE THE GULF STREAM IN THE 60S BEING THE BIGGEST. SO WHILE SOME DEVELOPMENT OF THIS SYSTEM IS EXPECTED A FULL BLOWN TROPICAL SYSTEM SEEMS TO BE A LONG SHOT. INSTEAD THE SYSTEM WILL PROBABLY ACQUIRE SOME TROPICAL CHARACTERISTICS BUT REMAIN QUITE WEAK AS IT WANDERS OVER THE WATERS OFF THE SOUTHEAST COAST. WORTH NOTING A LOT OF THE GFS ENSEMBLES TAKE THE WEAK LOW INTO FL OR SOUTHERN GA...SOMETHING WHICH A FAIR NUMBER OF THE MEMBERS HAVE BEEN CONSISTENTLY SHOWING OVER THE LAST FEW DAYS. LOCALLY IMPACTS THROUGH THE PERIOD WILL BE NORTHEAST FLOW...WITH SOME ENHANCEMENT LATER IN THE WEEK AND AN INCREASE IN LOW LEVEL MOISTURE. THIS SHOULD BRING ABOUT AN INCREASE IN PRECIP CHANCES...ESPECIALLY ALONG THE COAST...AS THE WEEK WEARS ON. GIVEN THE LOW CONFIDENCE PLAN TO MAKE ONLY SMALL CHANGES TO THE INHERITED FORECAST WHICH WILL NOW CARRY CHC POP THROUGH THE PERIOD WITH TEMPS NEAR TO SLIGHTLY ABOVE CLIMO. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 18Z...THE ONLY REAL CONCERN IS THE CONVECTIVE FIELD THAT LOOKS FAIRLY HEALTHY. HRRR STILL SHOWING A FEW SHOWERS DEVELOPING THIS AFTERNOON AS DOES THE GFS. WITH COASTAL TERMINALS NOW FIRMLY IN THE SEA BREEZE SHADOW...FEEL ANY ACTIVITY WILL NOT MAKE IT INTO THE INLAND TERMINALS. INCREASED THE MVFR FOG FOR CRE AND FLO LATE TONIGHT BASED ON THE LATEST NUMERICAL GUIDANCE...OTHERWISE VFR THROUGH THE PERIOD. EXTENDED OUTLOOK...PRE-DAWN MORNING FOG IS POSSIBLE EACH DAY THAT COULD RESULT IN MVFR/IFR CONDITIONS. UNSETTLED WEATHER THURSDAY NIGHT THROUGH SATURDAY WITH A SUBTROPICAL LOW. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM MONDAY...EXPECT ISOLATED SHOWERS CREEPING WESTWARD TOWARDS CAPE FEAR TO DIMINISH AS THEY BECOME INFLUENCED BY THE DOWNWARD COMPONENT OF THE SEA BREEZE CIRCULATION. OTHERWISE...ESE FLOW WILL BE THE STORY FOR THE REMAINDER OF THE DAY DUE TO SURFACE HIGH PRESSURE WELL OFF THE NC COAST. WIND SPEEDS AROUND 10 KNOTS ARE EXPECTED AS THE PRESSURE GRADIENT WILL REMAIN BENIGN THROUGH THE PERIOD. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...BERMUDA HIGH WILL MAINTAIN LIGHT EASTERLY FLOW TUE INTO WED. DURING THE SECOND HALF OF THE PERIOD THE HIGH WILL RETREAT NORTHEAST AS WEAK LOW PRESSURE EMERGES FROM THE BAHAMAS. WINDS WILL BACK TO NORTHEAST FOR WED AND WED NIGHT WITH A SLIGHT BUMP IS SPEED. CONFIDENCE WITH RESPECT TO THE AMOUNT OF STRENGTHENING THE LOW WILL UNDERGO AND ITS LOCATION IS RATHER LOW AND THUS FORECAST CONFIDENCE IS ALSO LOW. FOR NOW KEEPING WIND SPEEDS WED AND WED NIGHT CONFINED TO THE 15 TO 20 KT RANGE BUT HIGHER VALUES ARE POSSIBLE. SEAS 2 TO 3 FT TUE INTO WED SHOULD BUILD LATER WED AS NORTHEAST FLOW INCREASES AND COASTAL LOW STARTS TO BECOME A LITTLE MORE DEFINED. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3 AM MONDAY...MUCH OF THE FORECAST DEPENDS ON THE DETAILS OF THE HYBRID TROPICAL SYSTEM MEANDERING OFF THE SOUTHEAST COAST LATE THIS WEEK. WEAK STEERING FLOW ALOFT HAS SO FAR BEFUDDLED GUIDANCE AND NOT CONFIDENT CLARITY WILL DESCEND UPON THE FORECAST IN THE NEAR TERM. THAT SAID FEEL A FORECAST OF NORTHEAST FLOW IN THE 15 TO 20 KT RANGE IS A GOOD COMPROMISE AND IS IN LINE WITH PREVIOUS FORECASTS. SEAS WILL BUILD ON THE BACK OF EXTENDED NORTHEAST FLOW WITH SOME ZONES LIKELY TO EXCEED 6 FT IN PLACES ON THU AND REMAIN ABOVE 6 FT FRI. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...CRM SHORT TERM...III LONG TERM...III AVIATION...SHK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
623 PM EDT MON MAY 4 2015 .SYNOPSIS... A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS AFTERNOON AND EVENING. THE FRONT IS EXPECTED TO BECOME NEARLY STATIONARY OVER CENTRAL OHIO AND CENTRAL PENNSYLVANIA ON TUESDAY. THE FRONT WILL THEN LIFT BACK NORTH AS A WARM FRONT WEDNESDAY. THE LOCAL AREA WILL BE UNDER THE INFLUENCE OF HIGH PRESSURE OFF THE ATLANTIC COAST THROUGH THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... TWEAKED TIMING OF PRECIP AND REMOVED MENTION OF TSRA FOR THIS EVENING. BETTER CHANCE OF THUNDER OVERNIGHT. ORIGINAL DISCUSSION... COLD FRONT IS MAKING SLOW PROGRESS FROM WEST TO EAST. THE SHOWER ACTIVITY AHEAD OF THE FRONT IS ENCOUNTERING A LOT OF DRY AIR AHEAD OF THE PRECIPITATION. THIS IS HELPING TO REDUCE THE SHOWER POTENTIAL ACROSS THE AREA EVEN THOUGH TEMPERATURES EXCEEDED THE CONVECTIVE TEMPERATURE OF 74 DEGREES BY SEVERAL DEGREES. EXPECTING THE SHOWERS TO MOVE EAST ACROSS THE AREA WITH QPF AMOUNTS AROUND A TENTH OF AN INCH OR LESS THIS EVENING. THE FRONT EVENTUALLY BEGINS TO STALL JUST SOUTH OF THE LOCAL AREA BY MORNING. DUE TO THE CLOSE PROXIMITY OF THE FRONT TO THE AREA...THERE IS THE POSSIBILITY FOR SOME SHOWERS THROUGH THE NIGHT. WINDS WILL BEGIN TO DIMINISH THIS EVENING AS THE FRONT MOVES THROUGH THE AREA. COLD AIR ADVECTION ON THE NORTH SIDE OF THE COLD FRONT WILL CAUSE TEMPERATURES TO DIP BACK INTO THE 50S FOR LOWS NORTH. HOWEVER...SINCE SOUTHERN PORTIONS WILL TAKE THEIR TIME IN GETTING INTO THE COLDER AIR...LOWS ONCE AGAIN WILL BE AROUND 60 OVERNIGHT. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/... COLD FRONT BECOMES NEARLY STATIONARY JUST SOUTH OF THE FORECAST AREA ON TUESDAY. THIS WILL SET UP A NORTHEASTERLY FLOW DOWN THE SPINE OF LAKE ERIE INTO NORTHWEST OHIO. THIS WILL CAUSE COLD AIR ADVECTION OFF THE LAKE AS COLD DOME OF AIR MOVES INLAND. TEMPERATURES WILL LIKELY BE COOLER IN TOLEDO AND ALONG THE IMMEDIATE LAKE SHORE FOR HIGHS ON TUESDAY. AWAY FROM THE LAKE...AIR MASS IS NOT ALL THAT COLD SO WE SHOULD SEE TEMPERATURES REBOUNDING INTO THE LOWER AND MIDDLE 70S. LAKE BREEZE WILL LIKELY DEVELOP ALONG THE LAKE SHORE AND THIS WILL KEEP THE LAKE SHORE AREAS COOLER AS WELL. AS STATIONARY FRONT LINGERS ACROSS THE AREA...THREAT FOR SOME SHOWERS AND THUNDERSTORMS STILL POSSIBLE DURING THE DAY ON TUESDAY. SO WILL KEEP A MENTION GOING THROUGH THE DAY. FINALLY...FRONT BEGINS TO LIFT NORTH TUESDAY NIGHT INTO WEDNESDAY AND WE SHOULD SEE A REBOUND IN TEMPERATURES BACK INTO THE 70S ACROSS THE ENTIRE FORECAST AREA. ALTHOUGH...GRADIENT WILL BE WEAK AND LAKE BREEZE WILL LIKELY DEVELOP AGAIN KNOCKING DOWN TEMPERATURES ALONG THE SHORE. THE BEST SURGE OF WARM AIR TAKES PLACE ON THURSDAY AS SOUTHERLY FLOW RESUMES IN THE WARM SECTOR THANKS TO HIGH PRESSURE SITTING OFF THE ATLANTIC COAST. THIS WARM FLOW SHOULD KEEP TEMPERATURES ON THE MILD SIDE THROUGH THURSDAY NIGHT. THREATS FOR PRECIPITATION ARE MINIMIZED WEDNESDAY THROUGH THURSDAY NIGHT AS MOISTURE LIFTS NORTH OF THE AREA. && .LONG TERM /FRIDAY THROUGH MONDAY/... THE LONG TERM BEGINS IN FRIDAY WITH THE GFS AND ECMWF IN DECENT AGREEMENT SHOWING AN UPPER RIDGE ACROSS THE EASTERN GREAT LAKES INTO PA WITH A TROF MOVING EAST THROUGH CENTRAL CANADA. AT THE SURFACE...LOW PRESSURE WILL BE NEAR LAKE SUPERIOR WITH A COLD FRONT SOUTHWEST INTO THE CENTRAL/SOUTHERN PLAINS. THIS WILL BE A MILD/WARM PATTERN FOR NRN OHIO AND NWRN PA WITH SLY/SWLY FLOW OUT OF THE MISSISSIPPI VALLEY INTO THE AREA. MOISTURE ASSOCIATED WITH THIS FLOW LOOKS BEST ACROSS NORTHWEST OHIO ON FRIDAY SO WILL PUT A SLIGHT CHANCE IN THE GRIDS. MESOSCALE FORCING COULD HELP AFTERNOON/EVENING STORMS DEVELOP ALONG ANY LAKE BREEZE BUT FOR NOW WILL LEAVE OUT. NO BIG CHANGES THROUGH SATURDAY MORNING. SATURDAY AFTERNOON THE COLD FRONT WILL MOVE EAST INTO MICHIGAN. MOISTURE CONTINUE TO INCREASE ACROSS THE AREA AS THE UPPER RIDGE MOVES EAST. WOULD EXPECT MORE AFTERNOON/EVENING SHOWERS/STORMS ACROSS THE AREA AND WILL HAVE CHANCE POPS FOR ALL. MANUAL PROGS HAVE THE FRONT BECOMING MORE EAST/WEST AND STALLING JUST TO OUR NORTH SATURDAY NIGHT AS LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS. FRONT LIFTS A BIT NORTH FOR SUNDAY INTO MONDAY AS THE LOW MOVES ENE. WILL HAVE CONTINUED CHANCE POPS SATURDAY NIGHT THROUGH MONDAY FOR WHAT WILL LIKELY BE INCREASING DIURNAL ACTIVITY. AFTERNOON TEMPS IN THE 70S TO LOWER 80S. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... VFR CONDITIONS ACROSS THE AREA EARLY THIS AFTERNOON HOWEVER SHOWERS ARE MOVING INTO THE WESTERN COUNTIES AFFECTING KTOL AND SOON TO BE AFFECTING KFDY. ISOLATED MVFR WITHIN THE SHOWERS. THESE SHOWERS WILL PROGRESS EAST THROUGH THE AFTERNOON REACHING KCLE- KMFD 20-2030Z. EXPECTING A COUPLE HOURS OF SHOWERS WITH THE LINE. ALTHOUGH EMBEDDED THUNDER IS POSSIBLE LEFT OUT FOR THE TIME BEING AS CAPES ONLY MARGINALLY UNSTABLE CAPES. FOLLOWING THE HRRR AFTER THE LINE WE SHOULD GET A BREAK FOR SEVERAL HOURS FOLLOWED BY AN INCREASE OVERNIGHT AND INTO TUESDAY MORNING WITH THE NEXT UPSTREAM WAVE AND THE OVERRUNNING OF THE COLD FRONT WHICH DROP INTO THE AREA LATE. EXPECTING CONDITIONS TO DROP TO MVFR SECOND HALF OF THE NIGHT AS MOISTURE CONTINUES TO INCREASE. NON VFR FOR TUESDAY MORNING. .OUTLOOK...NON VFR POSSIBLE TUESDAY AFTERNOON/NIGHT IN SCATTERED SHOWERS AND THUNDERSTORMS. && .MARINE... MODELS SHOW A WEAK GRADIENT IN GENERAL FOR THE NEXT SEVERAL DAYS SO AM EXPECTING WINDS FROM 10 TO 15 KNOTS OR LESS THROUGH THE PERIOD. FOR TONIGHT SOUTHWEST FLOW WILL TURN NORTHEAST OVERNIGHT AS HIGH PRESSURE MOVES THROUGH THE CENTRAL LAKES AND A COLD FRONT DROPS ACROSS LAKE ERIE. EAST TO NORTHEAST FLOW WILL LAST INTO WEDNESDAY NIGHT BEFORE THE FRONT LIFTS BACK ACROSS THE LAKE AS A WARM FRONT TURNING WINDS SOUTHEAST. THURSDAY FRIDAY AND SATURDAY EXPECT SOUTH TO SOUTHWEST FLOW WITH LOW PRESSURE TO OUR WEST. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...LOMBARDY NEAR TERM...DJB/LOMBARDY SHORT TERM...LOMBARDY LONG TERM...TK AVIATION...TK MARINE...TK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
302 PM EDT MON MAY 4 2015 .SYNOPSIS... A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS AFTERNOON AND EVENING. THE FRONT IS EXPECTED TO BECOME NEARLY STATIONARY OVER CENTRAL OHIO AND CENTRAL PENNSYLVANIA ON TUESDAY. THE FRONT WILL THEN LIFT BACK NORTH AS A WARM FRONT WEDNESDAY. THE LOCAL AREA WILL BE UNDER THE INFLUENCE OF HIGH PRESSURE OFF THE ATLANTIC COAST THROUGH THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... COLD FRONT IS MAKING SLOW PROGRESS FROM WEST TO EAST. THE SHOWER ACTIVITY AHEAD OF THE FRONT IS ENCOUNTERING A LOT OF DRY AIR AHEAD OF THE PRECIPITATION. THIS IS HELPING TO REDUCE THE SHOWER POTENTIAL ACROSS THE AREA EVEN THOUGH TEMPERATURES EXCEEDED THE CONVECTIVE TEMPERATURE OF 74 DEGREES BY SEVERAL DEGREES. EXPECTING THE SHOWERS TO MOVE EAST ACROSS THE AREA WITH QPF AMOUNTS AROUND A TENTH OF AN INCH OR LESS THIS EVENING. THE FRONT EVENTUALLY BEGINS TO STALL JUST SOUTH OF THE LOCAL AREA BY MORNING. DUE TO THE CLOSE PROXIMITY OF THE FRONT TO THE AREA...THERE IS THE POSSIBILITY FOR SOME SHOWERS THROUGH THE NIGHT. WINDS WILL BEGIN TO DIMINISH THIS EVENING AS THE FRONT MOVES THROUGH THE AREA. COLD AIR ADVECTION ON THE NORTH SIDE OF THE COLD FRONT WILL CAUSE TEMPERATURES TO DIP BACK INTO THE 50S FOR LOWS NORTH. HOWEVER...SINCE SOUTHERN PORTIONS WILL TAKE THEIR TIME IN GETTING INTO THE COLDER AIR...LOWS ONCE AGAIN WILL BE AROUND 60 OVERNIGHT. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/... COLD FRONT BECOMES NEARLY STATIONARY JUST SOUTH OF THE FORECAST AREA ON TUESDAY. THIS WILL SET UP A NORTHEASTERLY FLOW DOWN THE SPINE OF LAKE ERIE INTO NORTHWEST OHIO. THIS WILL CAUSE COLD AIR ADVECTION OFF THE LAKE AS COLD DOME OF AIR MOVES INLAND. TEMPERATURES WILL LIKELY BE COOLER IN TOLEDO AND ALONG THE IMMEDIATE LAKE SHORE FOR HIGHS ON TUESDAY. AWAY FROM THE LAKE...AIR MASS IS NOT ALL THAT COLD SO WE SHOULD SEE TEMPERATURES REBOUNDING INTO THE LOWER AND MIDDLE 70S. LAKE BREEZE WILL LIKELY DEVELOP ALONG THE LAKE SHORE AND THIS WILL KEEP THE LAKE SHORE AREAS COOLER AS WELL. AS STATIONARY FRONT LINGERS ACROSS THE AREA...THREAT FOR SOME SHOWERS AND THUNDERSTORMS STILL POSSIBLE DURING THE DAY ON TUESDAY. SO WILL KEEP A MENTION GOING THROUGH THE DAY. FINALLY...FRONT BEGINS TO LIFT NORTH TUESDAY NIGHT INTO WEDNESDAY AND WE SHOULD SEE A REBOUND IN TEMPERATURES BACK INTO THE 70S ACROSS THE ENTIRE FORECAST AREA. ALTHOUGH...GRADIENT WILL BE WEAK AND LAKE BREEZE WILL LIKELY DEVELOP AGAIN KNOCKING DOWN TEMPERATURES ALONG THE SHORE. THE BEST SURGE OF WARM AIR TAKES PLACE ON THURSDAY AS SOUTHERLY FLOW RESUMES IN THE WARM SECTOR THANKS TO HIGH PRESSURE SITTING OFF THE ATLANTIC COAST. THIS WARM FLOW SHOULD KEEP TEMPERATURES ON THE MILD SIDE THROUGH THURSDAY NIGHT. THREATS FOR PRECIPITATION ARE MINIMIZED WEDNESDAY THROUGH THURSDAY NIGHT AS MOISTURE LIFTS NORTH OF THE AREA. && .LONG TERM /FRIDAY THROUGH SUNDAY/... THE LONG TERM BEGINS IN FRIDAY WITH THE GFS AND ECMWF IN DECENT AGREEMENT SHOWING AN UPPER RIDGE ACROSS THE EASTERN GREAT LAKES INTO PA WITH A TROF MOVING EAST THROUGH CENTRAL CANADA. AT THE SURFACE...LOW PRESSURE WILL BE NEAR LAKE SUPERIOR WITH A COLD FRONT SOUTHWEST INTO THE CENTRAL/SOUTHERN PLAINS. THIS WILL BE A MILD/WARM PATTERN FOR NRN OHIO AND NWRN PA WITH SLY/SWLY FLOW OUT OF THE MISSISSIPPI VALLEY INTO THE AREA. MOISTURE ASSOCIATED WITH THIS FLOW LOOKS BEST ACROSS NORTHWEST OHIO ON FRIDAY SO WILL PUT A SLIGHT CHANCE IN THE GRIDS. MESOSCALE FORCING COULD HELP AFTERNOON/EVENING STORMS DEVELOP ALONG ANY LAKE BREEZE BUT FOR NOW WILL LEAVE OUT. NO BIG CHANGES THROUGH SATURDAY MORNING. SATURDAY AFTERNOON THE COLD FRONT WILL MOVE EAST INTO MICHIGAN. MOISTURE CONTINUE TO INCREASE ACROSS THE AREA AS THE UPPER RIDGE MOVES EAST. WOULD EXPECT MORE AFTERNOON/EVENING SHOWERS/STORMS ACROSS THE AREA AND WILL HAVE CHANCE POPS FOR ALL. MANUAL PROGS HAVE THE FRONT BECOMING MORE EAST/WEST AND STALLING JUST TO OUR NORTH SATURDAY NIGHT AS LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS. FRONT LIFTS A BIT NORTH FOR SUNDAY INTO MONDAY AS THE LOW MOVES ENE. WILL HAVE CONTINUED CHANCE POPS SATURDAY NIGHT THROUGH MONDAY FOR WHAT WILL LIKELY BE INCREASING DIURNAL ACTIVITY. AFTERNOON TEMPS IN THE 70S TO LOWER 80S. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... VFR CONDITIONS ACROSS THE AREA EARLY THIS AFTERNOON HOWEVER SHOWERS ARE MOVING INTO THE WESTERN COUNTIES AFFECTING KTOL AND SOON TO BE AFFECTING KFDY. ISOLATED MVFR WITHIN THE SHOWERS. THESE SHOWERS WILL PROGRESS EAST THROUGH THE AFTERNOON REACHING KCLE- KMFD 20-2030Z. EXPECTING A COUPLE HOURS OF SHOWERS WITH THE LINE. ALTHOUGH EMBEDDED THUNDER IS POSSIBLE LEFT OUT FOR THE TIME BEING AS CAPES ONLY MARGINALLY UNSTABLE CAPES. FOLLOWING THE HRRR AFTER THE LINE WE SHOULD GET A BREAK FOR SEVERAL HOURS FOLLOWED BY AN INCREASE OVERNIGHT AND INTO TUESDAY MORNING WITH THE NEXT UPSTREAM WAVE AND THE OVERRUNNING OF THE COLD FRONT WHICH DROP INTO THE AREA LATE. EXPECTING CONDITIONS TO DROP TO MVFR SECOND HALF OF THE NIGHT AS MOISTURE CONTINUES TO INCREASE. NON VFR FOR TUESDAY MORNING. .OUTLOOK...NON VFR POSSIBLE TUESDAY AFTERNOON/NIGHT IN SCATTERED SHOWERS AND THUNDERSTORMS. && .MARINE... MODELS SHOW A WEAK GRADIENT IN GENERAL FOR THE NEXT SEVERAL DAYS SO AM EXPECTING WINDS FROM 10 TO 15 KNOTS OR LESS THROUGH THE PERIOD. FOR TONIGHT SOUTHWEST FLOW WILL TURN NORTHEAST OVERNIGHT AS HIGH PRESSURE MOVES THROUGH THE CENTRAL LAKES AND A COLD FRONT DROPS ACROSS LAKE ERIE. EAST TO NORTHEAST FLOW WILL LAST INTO WEDNESDAY NIGHT BEFORE THE FRONT LIFTS BACK ACROSS THE LAKE AS A WARM FRONT TURNING WINDS SOUTHEAST. THURSDAY FRIDAY AND SATURDAY EXPECT SOUTH TO SOUTHWEST FLOW WITH LOW PRESSURE TO OUR WEST. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...LOMBARDY NEAR TERM...LOMBARDY SHORT TERM...LOMBARDY LONG TERM...TK AVIATION...TK MARINE...TK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
129 PM EDT MON MAY 4 2015 .SYNOPSIS... LOW PRESSURE WILL TRACK NORTHEAST INTO QUEBEC TODAY WITH A TRAILING COLD FRONT SINKING SOUTH ACROSS MICHIGAN. THE FRONTAL BOUNDARY WILL APPROACH THE AREA AND STALL THROUGH WEDNESDAY...THEN LIFT BACK AS A WARM FRONT ON THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... TEMPERATURES ARE RISING WELL INTO THE 70S AT THIS TIME. BUMPED TEMPERATURES UP A COUPLE DEGREES INTO THE LOWER 80S EAST OF THE CLOUD COVER. BUMPED TEMPERATURES DOWN IN THE EXTREME WEST WHERE SHOWERS HAVE ARRIVED. OTHERWISE...NO OTHER MAJOR CHANGES TO THE FORECAST. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... WILL CONTINUE WITH LIKELY POPS AS THE FRONT SINKS SOUTH INTO NORTHERN OHIO THIS EVENING. THE PUSH OF MID-LEVEL DRY AIR GETS AS FAR SOUTH AS LAKE ERIE...WITH THE INSTABILITY AXIS WEAKENING OVERHEAD. THIS SHOULD RESULT IN A DECREASING TREND TO THUNDERSTORMS LATE TONIGHT. THE NEXT ROUND OF SHORTWAVE ENERGY WILL MOVE ALONG THE STALLED FRONTAL BOUNDARY ON TUESDAY AND SHOULD SEE SCATTERED TO NUMEROUS COVERAGE OF SHOWERS AND THUNDERSTORMS AGAIN. LOWERED HIGHS ON TUESDAY ACROSS THE NORTH AS WINDS DEVELOP OFF LAKE ERIE AND SUFFICIENT CLOUD COVER HAS A LIMITING EFFECT ON TEMPERATURES. A FEW OF THE SOUTHERN COUNTIES MAY STILL REACH THE MID 70S. THE RIDGE STARTS TO BUILD ALOFT FROM TUESDAY NIGHT INTO WEDNESDAY WHICH SHOULD BRING AN END TO CONVECTION. WILL HOLD ONTO THE LOW 20-30 PERCENT POPS ON WEDNESDAY WITH SOME UNCERTAINTY ON WHERE THE STALLED FRONTAL BOUNDARY WILL RESIDE AT THAT TIME. BY THURSDAY WE RETURN TO HAVING A DRY FORECAST AS THE CAP STRENGTHENS OVERHEAD. THE WARM FRONT LIFTS BACK EARLY THURSDAY WHICH SUPPORTS HIGHS IN THE MID 70S TO NEAR 80 FOR MUCH OF THE AREA. && .LONG TERM /FRIDAY THROUGH SUNDAY/... UPPER LEVEL RIDGE LOOKS LIKE IT WILL STILL BE IN CONTROL OF THE REGION ON FRIDAY. HOWEVER WITH AN INCREASE IN LOW LEVEL MOISTURE...STRONG HEATING AND THE POTENTIAL OF SOME CONVERGENCE ALONG A LAKE BREEZE AND OVER THE CENTRAL HIGHLANDS WE WILL NEED TO MENTION SOME THUNDER IN THE GRIDS. SINCE HEIGHTS ALOFT ARE RATHER HIGH IT WILL LIMIT THE COVERAGE OF ANY OF THE THUNDER. BY SATURDAY A COLD FRONT WILL MOVE INTO THE CENTRAL GREAT LAKES AND SHOULD BE ENOUGH TO INCREASE THUNDER CHANCES ACROSS THE WEST. A LAKE BOUNDARY MAY ALSO IGNITE A FEW STORMS ACROSS NE OHIO INTO NW PA. THERE SHOULD BE A LULL IN THUNDERSTORM ACTIVITY AFTER MIDNIGHT SATURDAY NIGHT BUT CHANCES WILL INCREASE ON SUNDAY AS THE WEAKENING COLD FRONT PASSES. CURRENT THINKING IS THAT THE COVERAGE WILL BE SCATTERED AT BEST. IT CONTINUES TO LOOK LIKE TEMPERATURES WILL REMAIN ABOVE AVERAGE WITH HIGHS GENERALLY WITHIN A COUPLE DEGREES OF 80. COOLER NEAR THE LAKESHORE. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... VFR CONDITIONS ACROSS THE AREA EARLY THIS AFTERNOON HOWEVER SHOWERS ARE MOVING INTO THE WESTERN COUNTIES AFFECTING KTOL AND SOON TO BE AFFECTING KFDY. ISOLATED MVFR WITHIN THE SHOWERS. THESE SHOWERS WILL PROGRESS EAST THROUGH THE AFTERNOON REACHING KCLE- KMFD 20-2030Z. EXPECTING A COUPLE HOURS OF SHOWERS WITH THE LINE. ALTHOUGH EMBEDDED THUNDER IS POSSIBLE LEFT OUT FOR THE TIME BEING AS CAPES ONLY MARGINALLY UNSTABLE CAPES. FOLLOWING THE HRRR AFTER THE LINE WE SHOULD GET A BREAK FOR SEVERAL HOURS FOLLOWED BY AN INCREASE OVERNIGHT AND INTO TUESDAY MORNING WITH THE NEXT UPSTREAM WAVE AND THE OVERRUNNING OF THE COLD FRONT WHICH DROP INTO THE AREA LATE. EXPECTING CONDITIONS TO DROP TO MVFR SECOND HALF OF THE NIGHT AS MOISTURE CONTINUES TO INCREASE. NON VFR FOR TUESDAY MORNING. .OUTLOOK...NON VFR POSSIBLE TUESDAY AFTERNOON/NIGHT IN SCATTERED SHOWERS AND THUNDERSTORMS. && .MARINE... SOUTHWESTERLY WINDS WILL INCREASE AHEAD OF A COLD FRONT THAT WILL MOVE ACROSS LAKE ERIE THIS EVENING. THESE SOUTHWESTERLY WINDS SHOULD BE IN THE 10 TO 20 KNOT RANGE THROUGH THE DAY WITH THE LARGER WAVES OF 2 TO 3 FEET ACROSS THE OPEN WATERS. WINDS AND WAVES WILL DECREASE TONIGHT AS THE COLD FRONT STALLS OVER NORTHERN OR CENTRAL OHIO. HIGH PRESSURE OVER SOUTHERN CANADA WILL PRODUCE NORTHEAST TO EAST WINDS THROUGH THURSDAY. MOST LOCATIONS WILL KEEP WIND SPEEDS IN THE 5 TO 10 KNOT RANGE BUT SOME LOCALLY HIGHER WINDS...MAYBE UP TO 15 KNOTS...ACROSS THE NEARSHORE WATERS WILL LIKELY OCCUR TUESDAY THROUGH THURSDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KEC NEAR TERM...LOMBARDY SHORT TERM...KEC LONG TERM...MULLEN AVIATION...TK MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1254 PM CDT MON MAY 4 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 400 AM CDT MON MAY 4 2015 CHALLENGING FORECAST LOOKS TO BEGIN WITH CHALLENGING SHORT TERM. OVERNIGHT...HAVE SEEN THE STRONG SURFACE FRONTAL BOUNDARY SETTLE INTO FAR SOUTHERN PORTIONS OF THE REGION...AS MUCH DRIER AIR HAS INVADED FROM THE NORTH BEHIND THE BOUNDARY. SEVERAL CONTRADICTING FACTORS TO THE SHORT TERM PRECIPITATION FORECAST. FIRST...VERY FEW SOLUTIONS HAVE AMPLE HANDLE ON THE DRY AIR INTRUSION AT LOWEST LEVELS...WITH DEWPOINTS INTO THE UPPER 20S AND 30S OVER ALL BUT THE EXTREME SOUTHEAST CWA. SECOND...THE DEGREE OF ELEVATED INSTABILITY ACROSS THE FAR SOUTHERN CWA IS LACKING IN SHORT TERM HIGH RESOLUTION MODELS...WHICH IS EVIDENT GIVEN RECENT UPTAKE IN SCATTERED BANDED CONVECTION FROM THE LOWER MISSOURI VALLEY EASTWARD ACROSS NORTHWEST IOWA FORCED IN BROAD JET ENTRANCE REGION. THIRD...DEALING WITH TYPICAL BATTLE OF LOWER VERSUS HIGHER RESOLUTION MODELS. LARGE SCALE SYNOPTIC TREND IS FOR LOWER LEVEL BAROCLINIC ZONE TO SETTLE FURTHER SOUTHWARD OVER LAST COUPLE OF MODEL RUNS. HOWEVER...SOME QUESTION AS TO HOW MUCH FURTHER THE MID LEVEL BOUNDARY WILL SETTLE GIVEN THE PROXIMITY OF UPPER LEVEL JET ENTRANCE REGION PASSING ACROSS THE AREA TODAY. HIGHER RESOLUTION MODELS GENERALLY MUCH MORE AGGRESSIVE WITH NORTHWARD SPREAD OF PRECIPITATION. HOWEVER...SHOULD MAKE NOTE THAT TREND IN RAP HAS BEEN TO ALLOW LESS AND LESS THREAT TO SOUTHERN CWA THROUGH THE DAY. EARLY ON THIS MORNING...SHOULD SEE A GRADUAL DECREASE IN THE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE FAR SOUTH EARLY THIS MORNING AS THE WAVE CONTINUES TO SHEAR AWAY. WILL SEE RIDGING BEGIN TO REESTABLISH PRESENCE...BUT BATTLE A SMALL WAVE WANDERING FROM KANSAS TOWARD EASTERN NEBRASKA LATER IN THE DAY. CONVECTION SHOULD BREAK OUT CLOSER TO THIS FEATURE AND THE DEEPER SYNOPTIC BOUNDARY...EXPANDING AND TRENDING TOWARD A MORE EASTWARD MOTION WITH TIME ALONG BAROCLINIC ZONE EXPANDING TOWARD THE SIOUX CITY AREA LATE DAY. GRADUALLY...THIS WAVE PULLS EASTWARD AND MAY SEE MOST EXPANSIVE COVERAGE BRUSH THROUGH THE SOUTHERN CWA DURING THE EVENING HOURS...THEN PROGRESS TOWARD A MORE SCATTERED COVERAGE AS MID LEVEL WAVE AND ISENTROPIC ASCENT PUSHES NORTHWARD WITH DEEPENING SOUTHERLY FLOW. OVERALL...WILL BE LOOKING FOR THUNDER COVERAGE TO BE SMALL FRACTION OF THE OVERALL PRECIPITATION...WITH BEST THREAT THROUGH THE SOUTHEAST HALF OF THE CWA OVERNIGHT. NO SEVERE STORMS ARE EXPECTED WITH MINIMAL ELEVATED INSTABILITY AND GENERALLY WEAK MID LEVEL FLOW. TEMPWISE...WILL SET UP FOR FAIRLY DECENT EASTERLY MIXING WITH DRY AIR...DESPITE A DECENT AMOUNT OF CLOUDINESS MOST LOCATIONS THROUGH THE DAY. HIGHS SHOULD BE MAINLY UPPER 60S TO LOWER 70S...ON THE WARM SIDE OF MIXING POTENTIAL DUE TO THE DRY AIR. INCREASING MOISTURE TONIGHT FROM SOUTH TO NORTH WILL DEFINE LOWS UNDER THICKER CLOUDS...MID 40S NORTH TO LOWER TO MID 50S SOUTH. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 400 AM CDT MON MAY 4 2015 A RATHER MESSY MEDIUM AND EXTENDED FORECAST IS IN STORE FOR THE REGION THIS WEEK AND INTO NEXT WEEKEND. THE LONG WAVE PATTERN WILL BE DOMINATED BY LONG WAVE RIDGING ACROSS THE CONUS THIS WEEK...WITH SEVERAL TROUGHS LIFTING THROUGH THE PLAINS. THE MAIN WEATHER FEATURE THROUGH WEDNESDAY/THURSDAY WILL BE A BROAD UPPER LOW CURRENTLY OVER THE SOUTHWESTERN UNITED STATES THAT IS EXPECTED TO SLIDE ALONG THE WESTERN PERIPHERY OF THE RIDGE. BY TUESDAY...THIS TROUGH WILL BEGIN TO NUDGE THE LOW-LVL BAROCLINIC ZONE NORTHWARD...WITH BROAD ISENTROPIC LIFT BRINING A CHANCE FOR SHOWERS TO THE AREA ON TUESDAY. THE PRIMARY CONCERN WILL BE JUST HOW WIDESPREAD THIS ACTIVITY WILL BE...AS SHORTWAVE ENERGY MOVING THROUGH LATER TONIGHT SLIDES EAST OF THE AREA ON TUESDAY...ONLY TO BE REPLACED BY SHORTWAVE RIDGING. AND ADDITIONAL FACTOR IS THE DEGREE OF DRY AIR REMAINING IN THE SUB-700 MB LAYER. WITH THE LIFT BROAD IN NATURE...AND MOISTURE LIMITED TO A DEGREE...QPF THROUGH TUESDAY NIGHT SHOULD BE FAIRLY LOW. THEN A STRONGER PORTION OF THE AFOREMENTIONED UPPER TROUGH WILL BEGIN TO LIFT INTO THE PLAINS ON WEDNESDAY. MODELS ALL IN GOOD AGREEMENT THAT REMNANT CONVECTION FROM TUESDAY NIGHT ON THE WESTERN PLAINS WILL LIFT INTO THE LOCAL AREA DURING THE DAY ON WEDNESDAY WITH BROAD AND STRONG ISENTROPIC LIFT ASSISTING IN THE DEVELOPMENT OF ADDITIONAL SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY THROUGH THE DAY. MOISTURE TRANSPORT RATHER IMPRESSIVE...BRINGING PWAT VALUES AROUND 1.5 INCHES INTO THE AREA. HOWEVER...A DISTINCT LACK OF INSTABILITY IS ASSOCIATED WITH THIS PRECIPITATION FOR MUCH OF WEDNESDAY...AND THIS SHOULD KEEP QPF DOWN. DEPENDING ON THE SPEED OF PRECIPITATION WEDNESDAY MORNING...WILL NEED TO WATCH FOR THE POTENTIAL OF CLOUDS SCATTERING LATER IN THE AFTERNOON. A SECONDARY ROUND OF CONVECTION WILL LIKELY DEVELOP ALONG INVERTED TROUGH OR DRYLINE ACROSS WESTERN NEBRASKA/KANSAS LATE WEDNESDAY AFTERNOON. ONCE FORMED...IT WILL LIFT NORTHEAST WITH THE SHORTWAVE WEDNESDAY NIGHT. MUCAPE VALUES COULD CLIMB AS HIGH AS 500- 1000 J/KG WEDNESDAY EVENING AND SHEAR WILL BE ON THE INCREASE...MAINLY SOUTH AND WEST OF THE JAMES RIVER. THAT SAID...FEEL THE GENERAL RISK OF SVR STORMS IS LOW...BUT COULD SEE MARGINAL OUTLOOK SLIDE A BIT FURTHER NORTH. I WOULD ANTICIPATE QUITE A BIT OF THUNDER AS THIS ACTIVITY LIFTS THROUGH THE AREA INTO THURSDAY MORNING. FEEL MOST OF THURSDAY WILL BE DRY...AS UPPER FORCING LIFTS NORTHEAST. THE UPPER TROUGH COULD LEAVE AN ELONGATED BOUNDARY ACROSS THE SOUTHERN ZONES BY THURSDAY AFTERNOON. MODELS STILL VARY SIGNIFICANTLY WITH THIS FRONT...BUT A DECENT BUILDUP OF INSTABILITY ALONG AND SOUTH OF IT COULD BE TAPPED INTO SHOULD A WEAK WAVE LIFT NORTHWARD IN THE SWLY FLOW ALOFT. SHEAR CONTINUES TO BE MARGINAL...BUT COULD SUPPORT A SEVERE STORM. FRIDAY MAY BE THE DRIEST DAY OF THE EXTENDED...AS MODELS ARE IN REASONABLE AGREEMENT FORMING A DEEP TROUGH OVER THE WESTERN THIRD OF THE CONUS. BEYOND FRIDAY...BEGINNING TO LOOK RATHER WET ACROSS MANY AREAS AS THIS UPPER TROUGH BEGINS TO LIFT INTO THE PLAINS AND EVENTUALLY GREAT LAKES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1254 PM CDT MON MAY 4 2015 VFR CONDITIONS WILL DOMINATE ACROSS THE REGION THROUGH TONIGHT...WITH A DRY EAST-NORTHEAST FLOW HOLDING PRECIP CHANCES LARGELY SOUTH OF THE AREA. EXCEPTION MAY BE A FEW LATE AFTERNOON OR EARLY EVENING SPRINKLES WORKING INTO KSUX AREA...WITH BETTER LOW LEVEL MOISTURE TRYING TO WORK INTO AREA AFTER 06Z-08Z EARLY TUESDAY MORNING. HAVE INTRODUCED MVFR CEILINGS INTO KSUX ALONG WITH MAINLY VFR VISIBILITY IN -SHRA AFTER THAT TIME. THE EAST TO NORTHEAST WINDS WILL GUST TO 20-25KT UNTIL AROUND SUNSET...THEN SHOULD DIMINISH TO AROUND 12KT OR LESS AS THEY GRADUALLY SWING AROUND TO THE SOUTHEAST THROUGH TUESDAY MORNING. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHAPMAN LONG TERM...DUX AVIATION...JH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1129 AM MDT MON MAY 4 2015 .UPDATE... ISSUED AT 1000 AM MDT MON MAY 4 2015 A CHECK OF THE I-80 WEBCAMS INDICATED THAT THE DENSE FOG WAS LIFTING BETWEEN CHEYENNE AND LARAMIE...ESPECIALLY AT THE SUMMIT. THE DENSE FOG ADVISORY WAS ALLOWED TO EXPIRE AT 10 AM...WITH AREAS OF FOG LINGERING THRU THE LATE MORNING. UPDATE ISSUED AT 459 AM MDT MON MAY 4 2015 WEBCAMS ALONG INTERSTATE 80 HAVE SHOWN VIS REALLY COMING DOWN FROM THE SUMMIT TO JUST EAST OF BUFORD. MOIST SOUTHEAST WINDS WILL CONTINUE THROUGH THE MORNING AND HRRR SHOWS LIFR CONDITIONS CONTINUING IN THE SOUTHERN LARAMIE RANGE AND TO THE EAST OF THE ALBANY-LARAMIE COUNTY LINE THROUGH 16Z. THUS...WITH THE EXPECTATION THAT THE FOG WILL BE QUITE PERSISTENT THROUGH MID MORNING...DECIDED TO ISSUE A DENSE FOG ADVISORY FOR THE SOUTHERN LARAMIE RANGE AND ADJACENT FOOTHILLS THRU 16Z. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 230 AM MDT MON MAY 4 2015 THE GFS AND NAM BOTH PROG A WEAK MID LEVEL VORT MAX MOVING INTO NORTHEAST COLORADO AND THE SOUTHERN NEBRASKA PANHANDLE THROUGH MID MORNING. RADAR IMAGERY SHOWS SOME WEAK ECHOES ACROSS PORTIONS OF NORTHERN COLORADO (GENERALLY MOVING NORTHWARD)...BUT NO LIGHTNING OR STRONGER CONVECTIVE CELLS. WHILE THESE SHOWERS COULD MOVE INTO AREAS ALONG INTERSTATE 80 THROUGH MID MORNING...ANY ACCUMULATIONS WILL BE LIGHT. WITH SFC HIGH PRESSURE ACROSS THE DAKOTAS...LOW LEVEL WINDS OVER THE PLAINS ARE TURNING TO THE EAST AND SOUTHEAST. THE HRRR HAS LIFR CONDITIONS DEVELOPING AFTER 10-11Z ALONG THE CHEYENNE RIDGE FROM THE INTERSTATE 80 SUMMIT TO CHEYENNE. WITH GOOD LOW LEVEL UPSLOPE...THESE LOWER CIGS AND VIS PERSIST THROUGH 18Z. THUS...KEPT THE MENTION OF FOG GOING THROUGH THE ENTIRE MORNING. TEMPS WILL BE AROUND 15 DEGREES COOLER TODAY FOR AREAS ALONG AND EAST OF THE LARAMIE RANGE IN THE POST FRONTAL AIR MASS. THE AIR MASS IS RATHER STABLE WITH LI VALUES GENERALLY ABOVE 0C...THUS AFTN CONVECTION WILL BE QUITE LIMITED. A BETTER CHANCE OF TSTMS WILL EXIST TO THE WEST OF THE LARAMIE RANGE. WHILE AN ISOLATED HIGHER RAINFALL AMOUNT IS POSSIBLE THROUGH MIDDAY TUESDAY...THE MODELS REALLY DO NOT SHOW MUCH QPF WITH THE INCREASED STABILITY. ON TUESDAY LOW CLOUDS WILL BE MUCH MORE WIDESPREAD AND PERSISTENT ACROSS THE PLAINS THROUGH THE MORNING OR EVEN EARLY AFTN WITH THE POTENTIAL FOR FOG ONCE AGAIN MAINLY ALONG THE CHEYENNE RIDGE. SUBTROPICAL MID LEVEL LOW OVER ARIZONA TODAY WILL PROGRESS NORTHEASTWARD INTO COLORADO ON TUESDAY. COOLING ALOFT AHEAD OF THIS FEATURE ALONG WITH INCREASING PW VALUES (UP TO 1.0 INCHES ACROSS THE PANHANDLE BY TUESDAY AFTN)...WILL PROMOTE A MORE WIDESPREAD COVERAGE OF SHOWERS AND TSTMS. HAVE THE HIGHEST POPS ON TUESDAY AFTN AND EVENING OVER THE PANHANDLE WHERE THE MODELS HAVE BEEN CONSISTENTLY SHOWING THE BEST FORCING. SPC DOES HAVE THE SOUTHERN PANHANDLE IN A MARGINAL RISK FOR SEVERE STORMS ON TUESDAY...HOWEVER WITH RATHER WEAK INSTABILITY AND SHEAR...ONLY SMALL HAIL WOULD BE A CONCERN. THE UPPER LEVEL WAVE WILL MOVE INTO WESTERN SOUTH DAKOTA BY WED WITH SFC WINDS BECOMING NORTH TO NORTHWEST OVER MUCH OF THE CWA BY THE AFTN. KEPT THE 40-50 PERCENT POPS GOING DURING THE AFTN AS RATHER HIGH PW VALUES (0.75-1.0 INCHES) ARE SHOWN ACROSS THE PLAINS ALONG WITH WEAK INSTABILITY. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 230 AM MDT MON MAY 4 2015 ACTIVE WEATHER IN THE LONG TERM CONTINUES WITH DAILY RAIN/THUNDER CHANCES ALSO THE POSSIBILITY OF A WINTER WEATHER EVENT FOR NEXT WEEKEND. FOR WEDNESDAY NIGHT...FIRST LOW LOOKS TO TRACK OFF TO THE NORTHEAST INTO CENTRAL SOUTH DAKOTA AND WE SHOULD BE SEEING SHOWERS AND THUNDERSTORMS COMING TO AN END BY LATE EVENING. ANOTHER COLD FRONT LOOKS TO MOVE INTO THE AREA THURSDAY MORNING WITH ANOTHER ROUND OF RAIN SHOWERS DEVELOPING ACROSS THE AREA THURSDAY AFTERNOON...PERSISTING INTO FRIDAY. REMARKABLY STRONG AGREEMENT BETWEEN THE GFS AND ECMWF ON THE MOVEMENT OF THE SECOND LOW THROUGH THE ROCKIES THROUGH THE WEEKEND. BOTH BRING THE LOW THROUGH SOUTHERN NEVADA FRIDAY...WITH IT EJECTING NORTHEAST INTO NORTHERN COLORADO SATURDAY NIGHT. BOTH SHOW -4 TO POSSIBLY -6C TEMPERATURES AT 700MB SATURDAY NIGHT INTO SUNDAY...WHICH WOULD TURN RAIN OVER TO SNOW FOR MANY LOCATIONS ABOVE 6000 FEET. NEED TO BE WATCHING FOR WINTER HEADLINES FOR POSSIBLE HEAVY SNOW THIS WEEKEND. WE WILL CERTAINLY BE MONITORING THIS LOW AS IT DRAWS CLOSER. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 1129 AM MDT MON MAY 4 2015 MVFR CIGS LIKELY TO CONTINUE TO AFFECT KCYS THIS AFTERNOON THEN LOWERING TO IFR/LIFR TONIGHT INTO TUESDAY MORNING. ELSEWHERE MAINLY VFR WITH SCTD SHOWERS INTO THIS EVENING...THEN LOWERING TO MORE WIDESPREAD MVFR/IFR CIGS WITH LOWERED VSBYS IN AREAS OF FOG. && .FIRE WEATHER... ISSUED AT 230 AM MDT MON MAY 4 2015 A COOL AND WET WEATHER PATTERN WILL MEAN MINIMAL FIRE WEATHER CONCERNS THROUGH THE WEEK. AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS CAN BE EXPECTED EACH DAY...WITH GOOD CHANCES FOR MEASURABLE PRECIPITATION AND WETTING RAINS. MINIMUM RELATIVE HUMIDITY VALUES SHOULD BE WELL ABOVE CRITICAL THRESHOLDS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...MJ SHORT TERM...ZF LONG TERM...GCC AVIATION...RE FIRE WEATHER...ZF