Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/21/15


AREA FORECAST DISCUSSION
NWS PUEBLO CO
603 PM MDT MON APR 20 2015 .UPDATE... ISSUED AT 553 PM MDT MON APR 20 2015 UPDATED TO ADJUST SHOWER CHANCES ACROSS THE PLAINS...GENERALLY SOUTH OF HIGHWAY 50 FOR THIS EVENING. MOST HIGH-RES MODELS HAVE AN AREA OF SHOWER ACTIVITY DROPPING ACROSS THE PLAINS AND MADE ADJUSTMENTS TO ACCOUNT FOR THIS. NO OTHER UPDATES AT THIS TIME. MOZLEY && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 318 PM MDT MON APR 20 2015 CURRENTLY... MODEST NW FLOW PREVAILS ALOFT ACROSS THE REGION. ISOLD TO SCTD SHRA AND -TSRA WERE NOTED OVER THE HIGHER TRRN AND WERE MOVING ONTO THE PLAINS. MOST UNSTABLE ATMOSPHERE WAS NOTED OVER THE SPANISH PEAKS REGION PER RADAR AND TOTAL LTG DATA. TEMPS WERE COOL AT 3 PM WITH TEMPS IN THE U50S/L60S PLAINS AND 50S VALLEYS. REST OF TODAY AND THIS EVENING.... ISOLD PRECIP ACTIVITY WILL CONTINUE OVER THE HIGHER TRRN WITH SOME OF THIS ACTIVITY MOVING ONTO THE PLAINS. ANY ACTIVITY OVER THE PLAINS WILL GENERALLY REMAIN ISOLD...WITH A BIT MORE COVERAGE EXPECTED ALONG THE CO/NM BORDER. ACTIVITY WILL REMAIN WEAK WITH BIGGEST CONCERN BEING CG ACTIVITY. TONIGHT... ANY PRECIP OVER THE REGION WILL DIE BY LATER THIS EVENING IF NOT EARLIER. HRRR AND NAM GUIDANCE DO SHOW A TSTORM OR TWO OVER THE PLAINS EARLY THIS EVENING UNDER THE MODEST NW FLOW. TEMPS WILL COO INTO THE 30-35F RANGE ACROSS THE PLAINS WITH 20S IN THE VALLEYS. TUESDAY... IT WILL BE WARMER TOMORROW WITH HIGHS EXPECTED TO REACH INTO THE LOWER 70S MOST OF THE PLAINS...AND 60S VALLEYS. I DO EXPECT THAT WE WILL SEE A PRECIP PATTERN SIMILAR TO TODAY IN THAT SHOWERS AND STORMS WILL FORM OVER THE MTNS AND MOVE ONTO THE PLAINS. ACTIVITY WILL BE A LITTLE MORE ROBUST TOMORROW AS WE SHOULD SEE A BIT MORE INSTABILITY TOMORROW...HOWEVER NO STRONG ACTIVITY IS ANTICIPATED AT THIS TIME. /HODANISH .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 318 PM MDT MON APR 20 2015 RELATIVELY ACTIVE LONGER TERM IS ANTICIPATED WITH PRIMARY METEOROLOGICAL ISSUES BEING POPS(INCLUDING THUNDERSTORMS AND MOUNTAIN SNOWS)...TEMPERATURES AND GUSTY WINDS AT TIMES. RECENT LONGER TERM COMPUTER SIMULATIONS...FORECAST MODEL SOUNDINGS...PV ANALYSIS AND ADDITIONAL METEOROLOGICAL PARAMETERS SUGGEST THAT TRANSITORY UPPER RIDGING TO SOUTHWESTERLY UPPER FLOW WILL BE IN PLACE OVER THE FORECAST DISTRICT FROM TUESDAY NIGHT INTO THURSDAY IN ADVANCE OF NEXT UPPER DISTURBANCE IMPACTING CWFA FROM LATER THURSDAY INTO FRIDAY NIGHT WITH ANOTHER UPPER DISTURBANCE IMPACTING THE FORECAST DISTRICT FROM SATURDAY INTO SATURDAY NIGHT. AT LOWER LEVELS...SURFACE HIGH CENTERED OVER SOUTH DAKOTA AT 06Z WEDNESDAY SLOWLY SHIFTS INTO THE UPPER MIDWEST BY FRIDAY NIGHT...WHILE SURFACE LOW DEVELOPS OVER SOUTHEASTERN COLORADO BY 06Z FRIDAY BEFORE SHIFTING INTO OKLAHOMA BY 06Z SATURDAY AS NORTHERLY SURFACE SURGE PUSHES ACROSS EASTERN SECTIONS FRIDAY NIGHT. THE COMBINATION OF THESE METEOROLOGICAL PARAMETERS IN COMBINATION WITH ADEQUATE ATMOSPHERIC MOISTURE WILL ALLOW FOR UNSETTLED CONDITIONS AT TIMES OVER THE CWFA DURING THE MAJORITY OF THE LONGER TERM IN COMBINATION WITH TEMPERATURES RUNNING WITHIN A CATEGORY OR SO OF MID TO LATE APRIL CLIMATOLOGICAL AVERAGES MOST LOCATIONS...ALTHOUGH SOME ADDITIONAL WARMING IS PROJECTED TO DEVELOP BY EARLY NEXT WEEK. AT THIS TIME...IT APPEARS THAT THE HIGHEST POTENTIAL OF STRONGER CONVECTIVE POTENTIAL DURING THE LONGER TERM MAY BE REALIZED WEDNESDAY AND THURSDAY(ESPECIALLY EASTERN SECTIONS) AS DEEPER ATMOSPHERIC MOISTURE INTERACTS WITH UPPER IMPULSES TO PRODUCE LOCALIZED POTENTIAL CAPES/LIS AND BULK SHEARS VALUES OF -5C/1000+ J/KG AND 40 KNOTS RESPECTIVELY BOTH DAYS. AS ALWAYS...WFO PUEBLO WILL MONITOR CLOSELY. IN ADDITION...HIGHER ELEVATION ACCUMULATING SNOW IS ANTICIPATED AT TIMES WITH GUSTY GRADIENT WINDS ALSO POSSIBLE...PRIMARILY FROM FRIDAY INTO FRIDAY NIGHT. FINALLY...AS BRIEFLY TOUCHED UPON EARLIER...WARMEST CONDITIONS DURING THE LONGER TERM SHOULD BE NOTED BY NEXT MONDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 318 PM MDT MON APR 20 2015 VFR CONDITIONS ARE ANTICIPATED DURING THE NEXT 24H AT ALL 3 TAF SITES...KPUB...KALS AND KCOS. VERY ISOLD TSRA WILL BE POSSIBLE THIS EVENING AND TOMORROW EVENING AT KCOS AND KPUB. WINDS WILL BE DIURNALLY DRIVEN AND WILL BE LIGHT. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MOZLEY
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1252 AM MDT SUN APR 19 2015 .UPDATE... ISSUED AT 1250 AM MDT SUN APR 19 2015 UPDATED TO REMOVE EXPIRED WINTER WEATHER HEADLINES. SIGNIFICANT SNOWFALL HAS ENDED IN THE NORTHERN AND CENTRAL MTS OF CO AND ONLY LIGHT ADDITIONAL ACCUMULATIONS AREA EXPECTED. UPDATE ISSUED AT 744 PM MDT SAT APR 18 2015 UPPER LOW CONTINUES TO ROTATE IN PLACE OVER THE EASTERN PLAINS THIS EVENING. WRAP AROUND MOISTURE KEEPING SNOW GOING IN THE HIGH COUNTRY...A MIXTURE ACROSS THE MESA AND PLATEAU REGION AND THUNDERSTORMS ACROSS EASTERN UTAH. STEEP LAPSE RATES DUE TO HEATING OUTSIDE OF THE THICKER CLOUD SHIELD IS AIDING THE WEAK WAVE DROPPING THROUGH EASTERN UTAH. STORMS STARTED OUT QUITE ROBUST WEST OF THE COLORADO RIVER...BUT AS THEY TRAVEL SOUTHEAST ACROSS THE INSTABILITY GRADIENT...THEY WEAKEN OVER OUR CWA. WILL LOSS OF HEATING EXPECT THE COVERAGE TO SLOWLY WANE OVER THE NEXT HOUR OR SO. WILL BE WATCHING THE AFFECT OF NIGHTFALL ON EASTERN PASSES AS MELTING HAS KEPT ROADS IN DECENT SHAPE. MAY KEEP SOME OF THE HEADLINES ALONG DIVIDE IF NECESSARY PAST MIDNIGHT. LASTLY DEW POINTS DID CREEP UP A BIT THIS AFTERNOON INTO THE 40S OVER THE WESTERN VALLEYS. WILL BE MONITORING THE THREAT OF DENSE FOG AS WELL. && .SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT) ISSUED AT 325 PM MDT SAT APR 18 2015 THE LOW PRESSURE RESPONSIBLE FOR THE MUCH NEEDED PRECIP OVER THE LAST FEW DAYS IS NOW LOCATED OVER THE FRONT PLAINS WHILE CYCLONIC FLOW CONTINUES TO PUMP IN MOISTURE FROM THE NORTH TO SOUTH. THIS FLOW STARTS IN NERN WY AND THE PLUME REACHES AS FAR SOUTH AS THE SAN JUANS. SNOW AND RAIN HAS FALLEN MUCH OF THE DAY UNDER THIS PLUME OF MOISTURE AND WILL CONTINUE TO DO SO THROUGH THIS EVENING. CURRENT WINTER HIGHLIGHTS LOOK GOOD SO NO CHANGES THERE. AN UPPER LEVEL DISTURBANCE OVER SRN CANADA IS TRAILING A TROUGH THAT IS CAUSING THE AREA OF LOW PRESSURE TO KEEP MOVING EWRD. THE REASON THIS IS HAPPENING SO SLOWLY IS THE LACK OF ANY STRONG JET FEATURES TO REALLY GET THIS SYSTEM MOVING. EVEN SO...THE CLOUD SHIELD/PLUME WILL BRING MORE PRECIP TO THE AREA AS THE ATTENDANT LOW PRESSURE MEANDERS EAST. BY MIDNIGHT...PRECIP WILL FAVOR THE NRN AND CENTRAL MTNS ALONG WITH THE FLATTOPS DUE TO THEIR FAVORABLE LOCATION SO ADDITIONAL ACCUMULATIONS STILL POSSIBLE UP THERE. THE REST OF THE CWA MAY SEE AN ODD SHOWER OR TWO BUT NOTHING TOO SIGNIFICANT. BY SUNDAY...THE CANADIAN LOW WILL BE JUST TO THE NORTH OF MINNESOTA WHILE HIGH PRESSURE BUILDS INTO THE PACNW. THIS WILL CAUSE OUR CWA TO BE SANDWICHED BETWEEN THESE TWO FEATURES. WEAK PIECES OF ENERGY WILL DROP DOWN FROM THE NW POSSIBLY CAUSING SOME PRECIP FOR THE CWA. THE GFS HIGHLIGHTING TWO DISTINCT WAVES...ONE SUNDAY EVENING AND ANOTHER MONDAY MORNING. THE NAM12 ONLY SHOWING SOME SPOTTY SHOWERS AT BEST WITH SOME CONVECTION THROWN IN. THE HRRR AND RAP SHOWING MUCH LESS IN THE WAY OF PRECIP. THIS ALL MEANS UNSETTLED WX WILL CONTINUE BUT WITH MUCH MORE DEFINITIVE BREAKS BETWEEN DISTURBANCES. FORECAST BRINGS MOSTLY BENIGN WEATHER SUNDAY WITH INCREASING CHANCES FOR PRECIP FROM MIDAFTERNOON ONWARDS...MAINLY FAVORING THE CONTINENTAL DIVIDE. TEMPS WILL WARM UP CONSIDERABLY TOMORROW THOUGH STILL REMAIN 5 TO 10 DEGREES BELOW NORMAL. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 325 PM MDT SAT APR 18 2015 UNSETTLED NW FLOW IS EXPECTED MONDAY AND TUESDAY. AN EMBEDDED WAVE SHOULD FOCUS THE BEST CHANCE OF SHOWERS OVER THE NORTHERN AND CENTRAL MOUNTAINS MONDAY AFTERNOON AND EVENING. DAYTIME INSTABILITY WILL KEEP ISOLATED TO SCATTERED SHOWERS OVER THE MTNS ON TUESDAY. TEMPORARY RIDGING DEVELOPS OVER THE AREA BY MIDWEEK AS A TROUGH FORMS ALONG THE WEST COAST...WITH AN UPPER LOW OVER SRN CA BY THU MORNING. ENOUGH RESIDUAL MOISTURE LINGERS FOR A FEW AFTERNOON SHOWERS OR THUNDERSTORMS. FLOW ALOFT BECOMES SOUTHWEST...AND THE SRN CA LIFTS ACROSS THE FOUR CORNERS/DESERT SOUTHWEST THU NIGHT AND FRI MORNING. TIMING AND TRACK A BIT DIFFERENT BETWEEN MODELS BUT STILL LOOKING LIKE A BETTER CHANCE OF PRECIPITATION WITH SOME THUNDERSTORMS LATE NEXT WEEK. BOOSTED POPS FOR THU AFTERNOON THROUGH FRI OVER THE BLENDED FORECAST GUIDANCE AS A RESULT. GFS AND ECMWF SOLUTIONS CONTINUE TO DIVERGE ON SATURDAY. ECMWF MORE AMPLIFIED AS IT DIGS A PAC NW TROUGH TO THE SRN GREAT BASIN BY SATURDAY...RESULTING IN DOWNSTREAM RIDGING AND SW FLOW OVER OUR AREA. GFS DROPS SOME ENERGY FROM THE PAC NW TROUGH DOWN THE WEST COAST BUT SENDS MORE OF IT ACROSS THE NRN ROCKIES WITH WESTERLY FLOW ACROSS UT/CO. WILL FOLLOW THE BLENDED GUIDANCE FOR SAT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1040 PM MDT SAT APR 18 2015 A HIGH LATITUDE SYSTEM DIVING INTO THE NORTHERN PLAINS WILL BE KICKING THIS STORM SYSTEM THAT HAS BEEN PARKED OVER COLORADO THE PAST SEVERAL DAYS. THIS WILL ALLOW PRECIPITATION COVERAGE TO TREND DOWNWARD OVER MOST OF WESTERN COLORADO AND EASTERN UTAH. THE HIGH DIVIDE MOUNTAINS WILL THE MOST LIKELY AREA TO KEEP COLLECTING LIGHT SNOW OVERNIGHT AND BE UNDER OBSCURATION. THE BIG CHALLENGE INTO MID MORNING SUNDAY WILL BE LOW CLOUDS AND FOG DUE TO A MOIST NEAR SURFACE LAYER FROM RECENT PRECIPITATION. THERE IS ALREADY A HINT OF THIS AT KRIL...KASE AND KMTJ LATE THIS EVENING AS CLOUD COVER ALOFT HAS THINNED. ANTICIPATE THIS WILL BECOME MORE OF A WIDESPREAD PROBLEM THROUGH THE NIGHT BRINGING IFR/LIFR TO MANY VALLEYS INCLUDING THE COLORADO TAF SITES. IMPROVEMENT SHOULD BE QUICKER SUNDAY MORNING WITH MORE SUNSHINE AVAILABLE TO BURN OFF THE LOW LEVEL MOISTURE. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ UPDATE...CC SHORT TERM...TGR LONG TERM...JAD AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1040 PM MDT SAT APR 18 2015 .UPDATE... ISSUED AT 744 PM MDT SAT APR 18 2015 UPPER LOW CONTINUES TO ROTATE IN PLACE OVER THE EASTERN PLAINS THIS EVENING. WRAP AROUND MOISTURE KEEPING SNOW GOING IN THE HIGH COUNTRY...A MIXTURE ACROSS THE MESA AND PLATEAU REGION AND THUNDERSTORMS ACROSS EASTERN UTAH. STEEP LAPSE RATES DUE TO HEATING OUTSIDE OF THE THICKER CLOUD SHIELD IS AIDING THE WEAK WAVE DROPPING THROUGH EASTERN UTAH. STORMS STARTED OUT QUITE ROBUST WEST OF THE COLORADO RIVER...BUT AS THEY TRAVEL SOUTHEAST ACROSS THE INSTABILITY GRADIENT...THEY WEAKEN OVER OUR CWA. WILL LOSS OF HEATING EXPECT THE COVERAGE TO SLOWLY WANE OVER THE NEXT HOUR OR SO. WILL BE WATCHING THE AFFECT OF NIGHTFALL ON EASTERN PASSES AS MELTING HAS KEPT ROADS IN DECENT SHAPE. MAY KEEP SOME OF THE HEADLINES ALONG DIVIDE IF NECESSARY PAST MIDNIGHT. LASTLY DEW POINTS DID CREEP UP A BIT THIS AFTERNOON INTO THE 40S OVER THE WESTERN VALLEYS. WILL BE MONITORING THE THREAT OF DENSE FOG AS WELL. && .SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT) ISSUED AT 325 PM MDT SAT APR 18 2015 THE LOW PRESSURE RESPONSIBLE FOR THE MUCH NEEDED PRECIP OVER THE LAST FEW DAYS IS NOW LOCATED OVER THE FRONT PLAINS WHILE CYCLONIC FLOW CONTINUES TO PUMP IN MOISTURE FROM THE NORTH TO SOUTH. THIS FLOW STARTS IN NERN WY AND THE PLUME REACHES AS FAR SOUTH AS THE SAN JUANS. SNOW AND RAIN HAS FALLEN MUCH OF THE DAY UNDER THIS PLUME OF MOISTURE AND WILL CONTINUE TO DO SO THROUGH THIS EVENING. CURRENT WINTER HIGHLIGHTS LOOK GOOD SO NO CHANGES THERE. AN UPPER LEVEL DISTURBANCE OVER SRN CANADA IS TRAILING A TROUGH THAT IS CAUSING THE AREA OF LOW PRESSURE TO KEEP MOVING EWRD. THE REASON THIS IS HAPPENING SO SLOWLY IS THE LACK OF ANY STRONG JET FEATURES TO REALLY GET THIS SYSTEM MOVING. EVEN SO...THE CLOUD SHIELD/PLUME WILL BRING MORE PRECIP TO THE AREA AS THE ATTENDANT LOW PRESSURE MEANDERS EAST. BY MIDNIGHT...PRECIP WILL FAVOR THE NRN AND CENTRAL MTNS ALONG WITH THE FLATTOPS DUE TO THEIR FAVORABLE LOCATION SO ADDITIONAL ACCUMULATIONS STILL POSSIBLE UP THERE. THE REST OF THE CWA MAY SEE AN ODD SHOWER OR TWO BUT NOTHING TOO SIGNIFICANT. BY SUNDAY...THE CANADIAN LOW WILL BE JUST TO THE NORTH OF MINNESOTA WHILE HIGH PRESSURE BUILDS INTO THE PACNW. THIS WILL CAUSE OUR CWA TO BE SANDWICHED BETWEEN THESE TWO FEATURES. WEAK PIECES OF ENERGY WILL DROP DOWN FROM THE NW POSSIBLY CAUSING SOME PRECIP FOR THE CWA. THE GFS HIGHLIGHTING TWO DISTINCT WAVES...ONE SUNDAY EVENING AND ANOTHER MONDAY MORNING. THE NAM12 ONLY SHOWING SOME SPOTTY SHOWERS AT BEST WITH SOME CONVECTION THROWN IN. THE HRRR AND RAP SHOWING MUCH LESS IN THE WAY OF PRECIP. THIS ALL MEANS UNSETTLED WX WILL CONTINUE BUT WITH MUCH MORE DEFINITIVE BREAKS BETWEEN DISTURBANCES. FORECAST BRINGS MOSTLY BENIGN WEATHER SUNDAY WITH INCREASING CHANCES FOR PRECIP FROM MIDAFTERNOON ONWARDS...MAINLY FAVORING THE CONTINENTAL DIVIDE. TEMPS WILL WARM UP CONSIDERABLY TOMORROW THOUGH STILL REMAIN 5 TO 10 DEGREES BELOW NORMAL. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 325 PM MDT SAT APR 18 2015 UNSETTLED NW FLOW IS EXPECTED MONDAY AND TUESDAY. AN EMBEDDED WAVE SHOULD FOCUS THE BEST CHANCE OF SHOWERS OVER THE NORTHERN AND CENTRAL MOUNTAINS MONDAY AFTERNOON AND EVENING. DAYTIME INSTABILITY WILL KEEP ISOLATED TO SCATTERED SHOWERS OVER THE MTNS ON TUESDAY. TEMPORARY RIDGING DEVELOPS OVER THE AREA BY MIDWEEK AS A TROUGH FORMS ALONG THE WEST COAST...WITH AN UPPER LOW OVER SRN CA BY THU MORNING. ENOUGH RESIDUAL MOISTURE LINGERS FOR A FEW AFTERNOON SHOWERS OR THUNDERSTORMS. FLOW ALOFT BECOMES SOUTHWEST...AND THE SRN CA LIFTS ACROSS THE FOUR CORNERS/DESERT SOUTHWEST THU NIGHT AND FRI MORNING. TIMING AND TRACK A BIT DIFFERENT BETWEEN MODELS BUT STILL LOOKING LIKE A BETTER CHANCE OF PRECIPITATION WITH SOME THUNDERSTORMS LATE NEXT WEEK. BOOSTED POPS FOR THU AFTERNOON THROUGH FRI OVER THE BLENDED FORECAST GUIDANCE AS A RESULT. GFS AND ECMWF SOLUTIONS CONTINUE TO DIVERGE ON SATURDAY. ECMWF MORE AMPLIFIED AS IT DIGS A PAC NW TROUGH TO THE SRN GREAT BASIN BY SATURDAY...RESULTING IN DOWNSTREAM RIDGING AND SW FLOW OVER OUR AREA. GFS DROPS SOME ENERGY FROM THE PAC NW TROUGH DOWN THE WEST COAST BUT SENDS MORE OF IT ACROSS THE NRN ROCKIES WITH WESTERLY FLOW ACROSS UT/CO. WILL FOLLOW THE BLENDED GUIDANCE FOR SAT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1040 PM MDT SAT APR 18 2015 A HIGH LATITUDE SYSTEM DIVING INTO THE NORTHERN PLAINS WILL BE KICKING THIS STORM SYSTEM THAT HAS BEEN PARKED OVER COLORADO THE PAST SEVERAL DAYS. THIS WILL ALLOW PRECIPITATION COVERAGE TO TREND DOWNWARD OVER MOST OF WESTERN COLORADO AND EASTERN UTAH. THE HIGH DIVIDE MOUNTAINS WILL THE MOST LIKELY AREA TO KEEP COLLECTING LIGHT SNOW OVERNIGHT AND BE UNDER OBSCURATION. THE BIG CHALLENGE INTO MID MORNING SUNDAY WILL BE LOW CLOUDS AND FOG DUE TO A MOIST NEAR SURFACE LAYER FROM RECENT PRECIPITATION. THERE IS ALREADY A HINT OF THIS AT KRIL...KASE AND KMTJ LATE THIS EVENING AS CLOUD COVER ALOFT HAS THINNED. ANTICIPATE THIS WILL BECOME MORE OF A WIDESPREAD PROBLEM THROUGH THE NIGHT BRINGING IFR/LIFR TO MANY VALLEYS INCLUDING THE COLORADO TAF SITES. IMPROVEMENT SHOULD BE QUICKER SUNDAY MORNING WITH MORE SUNSHINE AVAILABLE TO BURN OFF THE LOW LEVEL MOISTURE. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...WINTER STORM WARNING UNTIL MIDNIGHT MDT TONIGHT FOR COZ009-010- 012-017-018. WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR COZ003- 004-013. UT...NONE. && $$ UPDATE...15 SHORT TERM...TGR LONG TERM...JAD AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1039 PM EDT MON APR 20 2015 .SYNOPSIS... A WIND SWEPT SOAKING RAIN IS EXPECTED THROUGH THIS EVENING...WITH EVEN A FEW THUNDERSTORMS POSSIBLE TONIGHT. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ALONG WITH MILD TEMPS TUESDAY MORNING GIVES WAY TO A DRYING TREND DURING THE AFTERNOON. A COLD FRONT WILL BRING SCATTERED SHOWERS AND PERHAPS EVEN AN ISOLATED THUNDERSTORM OR TWO WEDNESDAY AFTERNOON AND EVENING. UNSEASONABLY COOL WEATHER FOLLOWS THURSDAY THROUGH THIS WEEKEND WITH JUST A SPOT SHOWER FROM TIME TO TIME. && .NEAR TERM /UNTIL MIDNIGHT TONIGHT/... 1030 PM UPDATE... NO MAJOR CHANGES TO ONGOING FORECAST THIS EVENING. DID TWEAK THE NEXT SEVERAL HOURS TO REFLECT THE LATEST OBSERVED TRENDS. THE MAIN CONCERN OVERNIGHT REMAINS THE POTENTIAL FOR CONVECTION. LATEST RUNS OF THE HRRR REMAIN BULLISH ON PRE-DAWN THUNDERSTORM POTENTIAL ACROSS RI AND SOUTHEAST MA...INCLUDING THE CAPE AND ISLANDS. WILL NEED TO CONTINUE TO MONITOR PROGRESS OF THUNDERSTORM CLUSTER OVER PA/NY THIS EVENING...SINCE THIS IS WHERE THE ENERGY WILL COME FROM. NOT EXPECTING SEVERE WEATHER AT THIS TIME. HEAVY RAINFALL IS NOT OUT OF THE QUESTION THOUGH. DEPENDING ON WHERE THIS HAPPENS...AND HOW FAST...WE COULD SEE SOME FLOODING ISSUES LATE TONIGHT. MAINLY EXPECTING NUISANCE FLOODING...BUT COULD BE MORE IF THE HEAVY RAINFALL OCCURS WITHIN SOME URBAN AREAS...SUCH AS FALL RIVER AND NEW BEDFORD. PREVIOUS DISCUSSION... THESE HEAVIER SHOWERS WERE BLOSSOMING ON THE NOSE OF THE LOW LEVEL JET/DRY SLOT ALLOWING FOR INCREASED INSTABILITY. GIVEN SHOWALTER INDICES DROPPING BELOW ZERO AND SOME ELEVATED CAPE...A FEW EMBEDDED THUNDERSTORMS ARE POSSIBLE THIS EVENING. WE PROBABLY WILL SEE A BIT OF A LULL IN THE ACTIVITY SOMETIME LATER THIS EVENING UNTIL THE NEXT BATCH OF ACTIVITY DEVELOPING ACROSS THE EASTERN GREAT LAKES/MID ATLANTIC TRACKS NORTHEAST. WHILE SEVERE WEATHER IS NOT EXPECTED...THIS MAY POSE A HIGHER RISK OF SCATTERED THUNDERSTORMS WITH HEAVY RAINFALL TOWARD DAYBREAK. THIS IS DISCUSSED FURTHER IN THE NEXT SECTION. FINALLY...AREAS OF FOG MAY BECOME LOCALLY DENSE. BEST CHANCE FOR THIS WILL BE LATER THIS EVENING WHEN WILL LIKELY SEE A LULL IN THE ACTIVITY AND WINDS DIMINISH A BIT. CONFIDENCE AND AREAL COVERAGE NOT HIGH ENOUGH TO ISSUE A DENSE FOG ADVISORY...BUT LATER SHIFTS WILL HAVE TO MONITOR. && .SHORT TERM /MIDNIGHT THROUGH 6 PM TUESDAY/... OVERNIGHT...THE WARM FRONT WILL MOVE NORTH OVER SOUTHERN NEW ENGLAND AND THE SOUTHERN PARTS OF THE AREA LOOK TO WARM SECTOR DURING THE EARLY MORNING HOURS. THIS WOULD INCLUDE RHODE ISLAND...SOUTHEASTERN MASSACHUSETTS...AND POSSIBLY PORTIONS OF NORTHERN CONNECTICUT. THIS WILL NOT ONLY BRING TEMPERATURES UP THROUGH THE NIGHT...BUT WILL ALSO ALLOW THE ATMOSPHERE TO FURTHER DESTABILIZE. K INDICES INCREASE AND SHOWALTER INDICES DECREASE AND ALONG WITH THE TOTAL TOTALS IN THE 50S THIS WILL RESULT IN SOME SURFACE BASED INSTABILITY ALONG WITH THE ELEVATED INSTABILITY ALREADY IN PLACE. THIS WILL PROVIDE A BETTER CHANCE OF THUNDER EARLY TUESDAY MORNING AS THE SHORTWAVE AND ATTENDANT COLD FRONT MOVE THROUGH THE REGION. EXPECT RAPID CLEARING BEHIND THE FRONT WITH TEMPERATURES SOARING INTO THE UPPER 60S TO NEAR 70 MOST LOCATIONS. WESTERLY WINDS WILL ALLOW EVEN THE COASTAL LOCATIONS TO GET IN ON THE WARM TEMPERATURES...UNLIKE SATURDAY. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... HIGHLIGHTS... * SCATTERED SHOWERS WED WITH A LOW RISK OF THUNDER/SMALL HAIL * SEASONABLY MILD TEMPERATURES WED * UNSEASONABLY COOL THU-SUN WITH A SPOT SHOWER OR TWO AT TIMES DETAILS... TUESDAY NIGHT... A SHORTWAVE WILL BE APPROACHING FROM THE WEST TUE NIGHT. MODELS DO NOT SHOW MUCH QPF AS INSTABILITY IS RATHER LIMITED. MAY SEE A FEW SPOT SHOWERS ESPECIALLY NORTH OF THE MA PIKE...BUT MUCH OF THE NIGHT SHOULD FEATURE DRY WEATHER IN A GIVEN LOCATION. LOW TEMPS WILL BOTTOM OUT IN THE 30S TO THE LOWER 40S. WEDNESDAY AND WEDNESDAY NIGHT... A FAIRLY STRONG SHORTWAVE AND ASSOCIATED COLD FRONT WILL CROSS THE REGION WED AFTERNOON AND EVENING. HIGH TEMPS SHOULD STILL REACH INTO INTO THE UPPER 50S TO MIDDLE 60S AHEAD OF THE FRONT. WE WILL SEE SCATTERED SHOWERS WITH THE FRONT GIVEN DECENT FORCING AND SOME MARGINAL INSTABILITY. MOST LIKELY TIME FRAME IS WED AFTERNOON AND EARLY EVENING. ITS QUITE COLD ALOFT AND MID LEVEL LAPSE RATES ARE VERY IMPRESSIVE AROUND 8C/KM! IF WE CAN MUSTER A FEW HUNDRED J/KG OF CAPE...MAY EVEN SEE AN EMBEDDED THUNDERSTORM OR TWO. CONFIDENCE ON THUNDER IS LOW AT THIS POINT...BUT GIVEN COLD POOL ALOFT THERE IS AT LEAST THIS RISK FOR SOME GRAUPEL/SMALL HAIL AND PERHAPS EVEN GUSTY WINDS IN THE HEAVIEST SHOWERS. THIS ACTIVITY SHOULD WIND DOWN BY WED EVENING. THURSDAY THROUGH MONDAY... ANOMALOUS CLOSED UPPER LEVEL LOW SETS UP ACROSS NORTHERN NEW ENGLAND AND INTO QUEBEC. THE RESULT WILL BE BELOW NORMAL HEIGHTS AND COOLER THAN NORMAL TEMPS IN SOUTHERN NEW ENGLAND. OVERALL...HIGH TEMPS WILL RANGE FROM THE UPPER 40S TO MIDDLE 50S MUCH OF THE TIME BUT SOME MODERATION IS POSSIBLE BY MONDAY. AS FOR PRECIP CHANCES...THE VAST MAJORITY OF THE TIME SHOULD FEATURE DRY WEATHER. HOWEVER...GIVEN COLD POOL ALOFT A FEW SPOT SHOWERS WILL BE POSSIBLE AT TIMES...ESPECIALLY IN NORTHERN SECTIONS DURING THE AFTERNOON HOURS. LOW RISK FOR EVEN A FEW WET SNOW FLAKES TO MIX IN FOR A TIME ACROSS THE HIGHER TERRAIN...BUT WOULD BE OF NO IMPACT. THERE IS ONE FLY IN THE OINTMENT. WE WILL HAVE TO WATCH A MORE SIGNIFICANT LOW PRESSURE SYSTEM SAT NIGHT/SUN. MOST OF THE MODEL GUIDANCE KEEPS THAT SYSTEM WELL TO OUR SOUTH. THE 12Z ECMWF IS A BIT CLOSER THEN THE REST OF THE GUIDANCE...BUT EVEN THAT WOULD KEEP US DRY. AGAIN...ODDS STRONGLY FAVOR KEEPING THIS SYSTEM SOUTH OR OUR REGION GIVEN ANOMALOUS CLOSED LOW SITTING JUST TO OUR NORTH. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT-TERM /THROUGH TUESDAY/... TONIGHT...IFR TO LIFR CONDITIONS CONTINUE. NUMEROUS SHOWERS WITH HEAVY RAINFALL EXPECTED. LULL FROM RAINFALL LIKELY SHORTLY AFTER MIDNIGHT...WHERE SOME LOCALLY DENSE FOG IS POSSIBLE. ANOTHER BATCH OF SHOWERS WITH A HIGHER RISK OF THUNDERSTORMS MOVES IN TOWARD DAYBREAK. E/SE-WINDS DIMINISHING. LLWS LIKELY INTO EARLY TUESDAY MORNING. TUESDAY...CONDITIONS IMPROVING TO VFR BY MIDDAY. COLD FRONT MOVES THROUGH WITH WINDS SHIFTING W/SW. KBOS TAF...MODERATE CONFIDENCE. CONCERNED ABOUT A PERIOD OF ONE HALF MILE OR LESS VISIBILITY OVERNIGHT BUT TIMING UNCERTAIN. IT MIGHT AFFECT THE MORNING PUSH. ALSO LOW RISK OF A THUNDERSTORM BETWEEN 8 AND 12Z. KBDL TAF...MODERATE CONFIDENCE. CONCERNED ABOUT A PERIOD OF ONE HALF MILE OR LESS VISIBILITY OVERNIGHT BUT TIMING UNCERTAIN. LOW RISK OF AN ISOLATED THUNDERSTORM OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY... TUE NIGHT...HIGH CONFIDENCE IN MAINLY VFR CONDITIONS DESPITE THE RISK FOR A SPOT SHOWER OR TWO. WED...MODERATE CONFIDENCE. A COLD FRONT WILL BRING A ROUND OF SCATTERED SHOWERS MAINLY WED AFTERNOON/EARLY EVENING. LOW RISK FOR EVEN A FEW RUMBLES OF THUNDER AND PERHAPS SMALL HAIL/GRAUPEL WITH THE HEAVIEST SHOWERS. THU/FRI/SAT...HIGH CONFIDENCE. MAINLY VFR DESPITE THE RISK FOR A BRIEF DIURNALLY DRIVEN SHOWER OR TWO. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY/... HIGH CONFIDENCE. GALE WARNINGS REMAIN IN PLACE FOR ALL THE WATERS OUTSIDE BOSTON HARBOR AND NARRAGANSETT BAY. CURRENT PLAN IS TO REPLACE SOME OF THE GALE WARNINGS WITH SMALL CRAFT ADVISORIES TOWARD MIDNIGHT...WHICH IS RIGHT ON SCHEDULE WITH PREVIOUS FORECAST. THIS IS FOR WIND GUSTS UP TO 35 KTS THROUGH THIS EVENING AND INTO THE NIGHT FOR THE OUTER WATERS. RAIN EXPECTED TO CONTINUE WITH STEADY RAIN COMING TO AN END LATE THIS EVENING AND TURNING MORE SHOWERY THROUGH MIDDAY TUESDAY. A FEW ISOLATED RUMBLES OF THUNDER ARE POSSIBLE THIS EVENING...WITH A BETTER CHANCE EARLY TUESDAY MORNING. VISIBILITIES MAY BE LIMITED AT TIMES. OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY... TUESDAY NIGHT AND WEDNESDAY...HIGH CONFIDENCE. MODEST WEST TO SOUTHWEST FLOW EXPECTED AHEAD OF A COLD FRONT...BUT SPEEDS SHOULD REMAIN BELOW SMALL CRAFT THRESHOLDS. A FEW SHOWERS WED AFTERNOON AND EVENING WITH A LOW RISK OF AN ISOLATED THUNDERSTORM WITH SMALL HAIL. THURSDAY THROUGH SATURDAY...HIGH CONFIDENCE. MODEST WESTERLY FLOW AS A RESULT OF CLOSED LOW PRESSURE ACROSS QUEBEC. ENOUGH COLD ADVECTION OVER THE WATERS WILL BE PRESENT TO GENERATE PERIODS OF 25 KNOT WIND GUSTS. MARGINAL SCA SEAS EXPECTED ACROSS THE OUTER-WATERS AT TIMES...BUT WITH GOOD VISIBILITY. && .TIDES/COASTAL FLOODING... EAST TO SOUTHEAST WINDS WILL INCREASE THROUGH TONIGHT. GUIDANCE CONTINUES TO TRACK STRONGEST WINDS ACROSS NEW ENGLAND EARLY THIS EVENING...BEFORE HIGH TIDE OCCURS ALONG THE SOUTH COAST /AROUND 03Z/ AND EAST COAST /ABOUT 06Z/. THIS RESULTS IN WINDS BEGINNING TO SLACKEN AS HIGH TIDE APPROACHES. ALSO SYSTEM IS FAIRLY PROGRESSIVE SO DURATION OF ONSHORE WINDS IS LIMITED. ESTOFS CONTINUES TO BE MORE ROBUST AND REALISTIC THAN ETSS WITH SURGE VALUES 1.0-1.5 FT AT THE TIME OF HIGH TIDE. SEAS ALSO BUILDING TO 10-15 FT JUST OFFSHORE. THIS SHOULD BE SUFFICIENT TO GENERATE AREAS OF MINOR COASTAL FLOODING AND SPLASH OVER. THUS WILL CONTINUE WITH A COASTAL FLOOD ADVISORY FOR THESE LOCATIONS DURING THIS EVENING AND EARLY TUE MORNING HIGH TIDES. WINDS DO NOT LOOK STRONG ENOUGH AT THE TIME OF HIGH TIDE FOR A MODERATE COASTAL FLOOD EVENT. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...COASTAL FLOOD ADVISORY UNTIL 4 AM EDT TUESDAY FOR MAZ007-015- 016-019-022-024. COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MAZ020- 021. RI...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR RIZ002- 004>007. MARINE...GALE WARNING UNTIL MIDNIGHT EDT TONIGHT FOR ANZ231>235-237-251. SMALL CRAFT ADVISORY UNTIL 4 AM EDT TUESDAY FOR ANZ230-236. GALE WARNING UNTIL 4 AM EDT TUESDAY FOR ANZ250-254>256. && $$ SYNOPSIS...FRANK/RLG NEAR TERM...BELK/FRANK SHORT TERM...RLG LONG TERM...FRANK AVIATION...BELK/FRANK/RLG MARINE...BELK/FRANK/RLG TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS ALBANY NY
1000 PM EDT MON APR 20 2015 .SYNOPSIS... .A LOW PRESSURE SYSTEM APPROACHING FROM THE WEST WITH ASSOCIATED FRONTS WILL BRING OCCASIONAL SHOWERS TO THE AREA ALONG WITH A FEW RUMBLES OF THUNDER TONIGHT. WITH A LARGE STATIONARY LOW OVER THE REGION...UNSETTLED WEATHER WILL CONTINUE THROUGH THE WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... THE WIND ADVISORY HAS BEEN CANCELED FOR THE HIGHER ELEVATIONS OF THE NORTH AND CENTRAL TACONICS...BERKSHIRES AND FOR BENNINGTON AND WESTERN WINDHAM COUNTIES. THE WINDS HAVE WEAKENED HOWEVER THEY DO REMAIN BRISK AND GUSTY IN THE WINDS HAVE WEAKENED HOWEVER THEY DO REMAIN BRISK AND GUSTY IN SOME LOCATIONS.SOME LOCATIONS. AS OF 945 PM...HAVE HAD A BIT OF A LULL IN THE PRECIPITATION THIS EVENING. HAVE SHOWERS ACTIVITY OCCURRING TO EAST AND CONVECTION TO OUR WEST IN THE VICINITY OF THE WARM FRONT. HAVE ADJUSTED POPS TO BETTER REFLECT CURRENT ACTIVITY. THE HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON CONVECTION SO HAVE USED IT AS A GUIDE TO INCREASE POPS THIS EVENING AS ANOTHER DISTURBANCE AHEAD AN OCCLUDING FRONTAL BOUNDARY INCREASES THE THREAT FOR CONVECTION. THE SYSTEM WILL OCCLUDE AS IT MOVES EASTWARD. WE ARE NOT EXPECTED TO GET INTO THE WARM SECTOR IT GETS PINCHED OFF JUST TO THE SOUTH OF OUR FORECAST AREA TONIGHT AS THE SYSTEM OCCLUDES. MODELS CONTINUE TO SHOW SOME ELEVATED INSTABILITY WITH SHOWALTER INDICES BELOW ZERO MOVING ACROSS THE REGION TONIGHT...SO HAVE KEEP MENTION OF THUNDER IN THE FORECAST. ANY THUNDERSTORMS THAT OCCUR COULD HAVE LOCALLY HEAVY DOWNPOURS...ESPECIALLY GIVEN THE STRONG THETA-E RIDGE WHICH DEVELOPS ACROSS THE REGION OVERNIGHT. TEMPERATURE TRENDS SINCE THE LAST UPDATE UNDER CLOUDY SKIES HAVE DROPPED SLOWLY WITH LOWS EXPECTED TO BE IN THE 40S. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... DURING THE DAY ON TUESDAY WE CAN EXPECT SOME LINGERING SHOWERS DURING THE DAY WITH SOME BREAKS OF SUN POSSIBLE IN THE AFTERNOON. THE UPPER LEVEL TROUGH AXIS WILL BE PASSING THROUGH THE AREA WITH AN ASSOCIATED VORT MAX. HIGH TEMPS ON TUESDAY ARE EXPECTED MAX TEMPS ARE FORECAST TO REACH THE LOWER/MID 60S IN VALLEY AREAS AND 50S ACROSS HIGHER ELEVATIONS. FOR TUESDAY NIGHT AND WEDNESDAY...A SECONDARY TROUGH IS EXPECTED TO MOVE FROM THE MIDWEST THROUGH CENTRAL NEW YORK AND CENTRAL PENNSYLVANIA BRINGING ANOTHER ROUND OF SHOWERS AND THIS WILL BE FOLLOWED BY YET ANOTHER TROUGH OF LOW PRESSURE ON WEDNESDAY. THIS IS ALL OCCURRING AT THE SURFACE WHILE ALOFT AN UPPER LEVEL CLOSED LOW SITS AND SPINS JUST NORTH OF THE UPPER GREAT LAKES SENDING PIECES OF ENERGY IN THE FORM OF VORT LOBES ACROSS OUR FA DURING MUCH OF THE PERIOD. EXPECT LOWS ON TUESDAY NIGHT ARE EXPECTED TO RANGE FROM THE UPPER 20S NORTHWEST TO AROUND 40 SOUTHEAST. SOME LIGHT SNOW ACCUMULATIONS GENERALLY UNDER AN INCH ARE POSSIBLE ACROSS THE WESTERN ADIRONDACKS. HIGHS ON WEDNESDAY ARE EXPECTED TO RANGE FROM THE UPPER 40S NORTHWEST TO AROUND 690 NORTHWEST. FOR WEDNESDAY NIGHT AND THURSDAY NOT MUCH IMPROVEMENT IS EXPECTED AS THE UPPER LEVEL TROUGH AXIS SETTLES ACROSS THE NORTHEAST US WHILE AT THE SURFACE LOW PRESSURE INTENSIFIES ACROSS THE GULF OF MAINE WITH YET ANOTHER COLD FRONT EXPECTED TO MOVE INTO THE EASTERN GREAT LAKES BY THURSDAY. THUS THERE WILL STILL BE SCATTERED SHOWERS AROUND ALTHOUGH THE PCPN SHOULD BE MAINLY ON THE LIGHT SIDE. EXPECT LOWS WEDNESDAY NIGHT TO BE IN THE UPPER 20S TO UPPER 30S WITH ONCE AGAIN A LITTLE LIGHT SNOW POSSIBLE ACROSS THE WESTERN ADIRONDACKS WITH HIGHS ON THURSDAY IN THE MID 40S TO LOWER 50S. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... BELOW NORMAL TEMPERATURES ALONG WITH SOME INTERVALS OF RAIN AND EVEN SNOW SHOWERS ARE EXPECTED THROUGH THE WEEKEND. MODEL GUIDANCE REMAINS IN GOOD AGREEMENT INDICATING A LARGE SCALE UPPER LOW WILL DOMINATE OUR WEATHER. HOWEVER THERE CONTINUES TO BE SOME DISAGREEMENT ON ITS EXACT TRACK AND WITH THE TIMING OF INDIVIDUAL SHORT WAVE ROTATING ABOUT IT. THERE IS CONSENSUS THE CENTER OF THE UPPER LOW SHOULD REMAIN TO OUR NORTH AS IT MOVES ACROSS EASTERN CANADA KEEPING OUR THE REGION IN WESTERLY FLOW. HAVE FAVORED GUIDANCE FROM THE WEATHER PREDICTION CENTER TO MAINTAIN FORECAST CONSISTENCY. THE BETTER CHANCES FOR SCATTERED SHOWERS WILL BE ACROSS THE HIGHER TERRAIN. RAIN SHOWERS ARE EXPECTED DURING THE DAY...BUT AT NIGHT IT WILL BE COLD ENOUGH FOR SNOW SHOWER ESPECIALLY ACROSS THE HIGHER ELEVATIONS. OVERALL EXPECTING HIGHS IN THE 40S AND 50S WITH LOWS IN THE 20S AND 30S. NORMALS FOR LATE APRIL... ALBANY NY: HIGHS IN THE LOWER 60S AND LOWS IN THE LOWER 40S. GLENS FALLS NY: HIGHS IN THE LOWER 60S AND LOWS IN THE UPPER 30S. POUGHKEEPSIE NY: HIGHS IN THE MID 60S AND LOWS AROUND 40. BENNINGTON VT: HIGHS IN THE LOWER 60S AND LOWS IN THE UPPER 30S. PITTSFIELD MA: HIGHS IN THE UPPER 50S AND LOWS IN THE MID 30S. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... A LOW PRESSURE SYSTEM WILL OCCLUDE AS IT MOVES ACROSS THE REGION TONIGHT. WE HAVE HAD A BIT OF A LULL IN THE PRECIPITATION THIS EVENING. HAVE SHOWERS ACTIVITY OCCURRING TO EAST AND CONVECTION TO OUR WEST IN THE VICINITY OF THE WARM FRONT. THE HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON CONVECTION SO HAVE USED IT AS A GUIDE TO INCREASE POPS THIS EVENING WITH THE BEST CHANCES AS WE APPROACH MIDNIGHT AS ANOTHER DISTURBANCE AHEAD THE OCCLUDING FRONTAL BOUNDARY WILL INCREASE THE THREAT FOR CONVECTION. WE ARE NOT EXPECTED TO GET INTO THE WARM SECTOR IT GETS PINCHED OFF JUST TO THE SOUTH OF OUR FORECAST AREA TONIGHT AS THE SYSTEM OCCLUDES. THE MODELS CONTINUE TO SHOW SOME ELEVATED INSTABILITY WITH SHOWALTER INDICES BELOW ZERO MOVING ACROSS THE REGION TONIGHT...SO THERE IS A CHANCE FOR THUNDERSTORMS HOWEVER CONFIDENCE IS TOO LOW TO INCLUDE IN THE TAFS. CONDITIONS WILL LOWER WITH WIDESPREAD MVFR-IFR DEVELOPING. A GRADUAL IMPROVEMENT WILL OCCUR WITH THE PASSAGE OF THE OCCLUDED FRONT. WITH WIDESPREAD VFR FOR THE AFTERNOON. HAVE NORTHEAST TO SOUTHEAST FLOW ACROSS AREA. RECENT OBSERVATIONS SHOWN A DIMINISHING TREND IN WIND GUSTS ACROSS THE BERKSHIRES... TACONICS AND SOUTHERN VERMONT WHERE THE FLOW HAS BEEN ENHANCED BY THE TERRAIN. WINDS WILL LIGHTEN AS THE OCCLUDED BOUNDARY MOVES THOUGH WITH A SHIFT TO SOUTHWEST TO WEST WITH ITS PASSAGE. WESTERLY WINDS WILL INCREASE TO 10 TO 15 KNOTS AND WILL BE GUSTY ESPECIALLY AT KALB AND KPSF. OUTLOOK... TUE NIGHT-WED: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. WED NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN. THU: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. THU NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. FRI: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. SAT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. && .FIRE WEATHER... THERE ARE NO FIRE WEATHER CONCERNS THIS WEEK AS WE WILL BE UNDER THE INFLUENCE OF AN UPPER LEVEL TROUGH. A WIDESPREAD SOAKING RAINFALL WILL OCCUR ACROSS THE AREA THROUGH TONIGHT...WITH RAINFALL AMTS OF 0.75-1.5 INCHES EXPECTED. THE WEATHER WILL BE COOL AND UNSETTLED FOR MUCH OF THE WEEK. && .HYDROLOGY... A WIDESPREAD SOAKING RAINFALL WILL OCCUR ACROSS THROUGH TONIGHT. EXPECTING WIDESPREAD QPF AMOUNTS OF AROUND AN INCH WITH HIGHER AMOUNTS UP TO AROUND 1.5 INCHES WHERE THE RAINFALL IS ENHANCED BY THE STRONG EAST TO SOUTHEAST FLOW...PARTICULARLY ACROSS THE CENTRAL AND SOUTHEASTERN CATSKILLS...TACONICS...BERKSHIRES INTO THE LITCHFIELD HILLS AND ACROSS SOUTHERN VERMONT. LOCALIZED HIGHER AMOUNTS OF 2 TO 3 INCHES WILL BE POSSIBLE. THERE IS STILL SOME SNOW COVER LEFT IN THE FORECAST AREA. BASED ON NATIONAL OPERATIONAL HYDROLOGIC REMOTE SENSING CENTER (NOHRSC) THIS IS ACROSS THE PORTIONS OF THE WESTERN ADIRONDACKS AND ACROSS THE HIGHER TERRAIN OF THE SOUTHERN GREEN MOUNTAINS. BASED ON CURRENT FORECASTS...ONLY THE WEST CANADA CREEK AT HINCKLEY DAM IS EXPECTED TO EXCEED ITS FLOOD STAGE BY TUESDAY EVENING. THE REST OF THE WEEK THE FORECAST WILL BE DOMINATED BY A PERSISTENT UPPER LEVEL TROUGH WHICH WILL RESULT IN COOL TEMPERATURES...BREEZY CONDITIONS AND OCCASIONAL CHANCES FOR MAINLY LIGHT PRECIPITATION. FOR DETAILS ON SPECIFIC AREA RIVER 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...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...IAA/KL/LFM/11/WASULA NEAR TERM...IAA/LFM/11/WASULA SHORT TERM...11 LONG TERM...IAA AVIATION...IAA/WASULA FIRE WEATHER...11 HYDROLOGY...IAA/KL/11
AREA FORECAST DISCUSSION
NWS ALBANY NY
947 PM EDT MON APR 20 2015 .SYNOPSIS... .A LOW PRESSURE SYSTEM APPROACHING FROM THE WEST WITH ASSOCIATED FRONTS WILL BRING OCCASIONAL SHOWERS TO THE AREA ALONG WITH A FEW RUMBLES OF THUNDER TONIGHT. WITH A LARGE STATIONARY LOW OVER THE REGION...UNSETTLED WEATHER WILL CONTINUE THROUGH THE WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... THE WIND ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT FOR THE HIGHER ELEVATIONS OF THE NORTH AND CENTRAL TACONICS...BERKSHIRES AND FOR BENNINGTON AND WESTERN WINDHAM COUNTIES. HOWEVER RECENT OBSERVATIONS SHOWN A DIMINISHING TREND IN WIND GUSTS. AS OF 945 PM...HAVE HAD A BIT OF A LULL IN THE PRECIPITATION THIS EVENING. HAVE SHOWERS ACTIVITY OCCURRING TO EAST AND CONVECTION TO OUR WEST IN THE VICINITY OF THE WARM FRONT. HAVE ADJUSTED POPS TO BETTER REFLECT CURRENT ACTIVITY. THE HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON CONVECTION SO HAVE USED IT AS A GUIDE TO INCREASE POPS THIS EVENING AS ANOTHER DISTURBANCE AHEAD AN OCCLUDING FRONTAL BOUNDARY INCREASES THE THREAT FOR CONVECTION. THE SYSTEM WILL OCCLUDE AS IT MOVES EASTWARD. WE ARE NOT EXPECTED TO GET INTO THE WARM SECTOR IT GETS PINCHED OFF JUST TO THE SOUTH OF OUR FORECAST AREA TONIGHT AS THE SYSTEM OCCLUDES. MODELS CONTINUE TO SHOW SOME ELEVATED INSTABILITY WITH SHOWALTER INDICES BELOW ZERO MOVING ACROSS THE REGION TONIGHT...SO HAVE KEEP MENTION OF THUNDER IN THE FORECAST. ANY THUNDERSTORMS THAT OCCUR COULD HAVE LOCALLY HEAVY DOWNPOURS...ESPECIALLY GIVEN THE STRONG THETA-E RIDGE WHICH DEVELOPS ACROSS THE REGION OVERNIGHT. TEMPERATURE TRENDS SINCE THE LAST UPDATE UNDER CLOUDY SKIES HAVE DROPPED SLOWLY WITH LOWS EXPECTED TO BE IN THE 40S. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... DURING THE DAY ON TUESDAY WE CAN EXPECT SOME LINGERING SHOWERS DURING THE DAY WITH SOME BREAKS OF SUN POSSIBLE IN THE AFTERNOON. THE UPPER LEVEL TROUGH AXIS WILL BE PASSING THROUGH THE AREA WITH AN ASSOCIATED VORT MAX. HIGH TEMPS ON TUESDAY ARE EXPECTED MAX TEMPS ARE FORECAST TO REACH THE LOWER/MID 60S IN VALLEY AREAS AND 50S ACROSS HIGHER ELEVATIONS. FOR TUESDAY NIGHT AND WEDNESDAY...A SECONDARY TROUGH IS EXPECTED TO MOVE FROM THE MIDWEST THROUGH CENTRAL NEW YORK AND CENTRAL PENNSYLVANIA BRINGING ANOTHER ROUND OF SHOWERS AND THIS WILL BE FOLLOWED BY YET ANOTHER TROUGH OF LOW PRESSURE ON WEDNESDAY. THIS IS ALL OCCURRING AT THE SURFACE WHILE ALOFT AN UPPER LEVEL CLOSED LOW SITS AND SPINS JUST NORTH OF THE UPPER GREAT LAKES SENDING PIECES OF ENERGY IN THE FORM OF VORT LOBES ACROSS OUR FA DURING MUCH OF THE PERIOD. EXPECT LOWS ON TUESDAY NIGHT ARE EXPECTED TO RANGE FROM THE UPPER 20S NORTHWEST TO AROUND 40 SOUTHEAST. SOME LIGHT SNOW ACCUMULATIONS GENERALLY UNDER AN INCH ARE POSSIBLE ACROSS THE WESTERN ADIRONDACKS. HIGHS ON WEDNESDAY ARE EXPECTED TO RANGE FROM THE UPPER 40S NORTHWEST TO AROUND 690 NORTHWEST. FOR WEDNESDAY NIGHT AND THURSDAY NOT MUCH IMPROVEMENT IS EXPECTED AS THE UPPER LEVEL TROUGH AXIS SETTLES ACROSS THE NORTHEAST US WHILE AT THE SURFACE LOW PRESSURE INTENSIFIES ACROSS THE GULF OF MAINE WITH YET ANOTHER COLD FRONT EXPECTED TO MOVE INTO THE EASTERN GREAT LAKES BY THURSDAY. THUS THERE WILL STILL BE SCATTERED SHOWERS AROUND ALTHOUGH THE PCPN SHOULD BE MAINLY ON THE LIGHT SIDE. EXPECT LOWS WEDNESDAY NIGHT TO BE IN THE UPPER 20S TO UPPER 30S WITH ONCE AGAIN A LITTLE LIGHT SNOW POSSIBLE ACROSS THE WESTERN ADIRONDACKS WITH HIGHS ON THURSDAY IN THE MID 40S TO LOWER 50S. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... BELOW NORMAL TEMPERATURES ALONG WITH SOME INTERVALS OF RAIN AND EVEN SNOW SHOWERS ARE EXPECTED THROUGH THE WEEKEND. MODEL GUIDANCE REMAINS IN GOOD AGREEMENT INDICATING A LARGE SCALE UPPER LOW WILL DOMINATE OUR WEATHER. HOWEVER THERE CONTINUES TO BE SOME DISAGREEMENT ON ITS EXACT TRACK AND WITH THE TIMING OF INDIVIDUAL SHORT WAVE ROTATING ABOUT IT. THERE IS CONSENSUS THE CENTER OF THE UPPER LOW SHOULD REMAIN TO OUR NORTH AS IT MOVES ACROSS EASTERN CANADA KEEPING OUR THE REGION IN WESTERLY FLOW. HAVE FAVORED GUIDANCE FROM THE WEATHER PREDICTION CENTER TO MAINTAIN FORECAST CONSISTENCY. THE BETTER CHANCES FOR SCATTERED SHOWERS WILL BE ACROSS THE HIGHER TERRAIN. RAIN SHOWERS ARE EXPECTED DURING THE DAY...BUT AT NIGHT IT WILL BE COLD ENOUGH FOR SNOW SHOWER ESPECIALLY ACROSS THE HIGHER ELEVATIONS. OVERALL EXPECTING HIGHS IN THE 40S AND 50S WITH LOWS IN THE 20S AND 30S. NORMALS FOR LATE APRIL... ALBANY NY: HIGHS IN THE LOWER 60S AND LOWS IN THE LOWER 40S. GLENS FALLS NY: HIGHS IN THE LOWER 60S AND LOWS IN THE UPPER 30S. POUGHKEEPSIE NY: HIGHS IN THE MID 60S AND LOWS AROUND 40. BENNINGTON VT: HIGHS IN THE LOWER 60S AND LOWS IN THE UPPER 30S. PITTSFIELD MA: HIGHS IN THE UPPER 50S AND LOWS IN THE MID 30S. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... A LOW PRESSURE SYSTEM WILL OCCLUDE AS IT MOVES ACROSS THE REGION TONIGHT. WE HAVE HAD A BIT OF A LULL IN THE PRECIPITATION THIS EVENING. HAVE SHOWERS ACTIVITY OCCURRING TO EAST AND CONVECTION TO OUR WEST IN THE VICINITY OF THE WARM FRONT. THE HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON CONVECTION SO HAVE USED IT AS A GUIDE TO INCREASE POPS THIS EVENING WITH THE BEST CHANCES AS WE APPROACH MIDNIGHT AS ANOTHER DISTURBANCE AHEAD THE OCCLUDING FRONTAL BOUNDARY WILL INCREASE THE THREAT FOR CONVECTION. WE ARE NOT EXPECTED TO GET INTO THE WARM SECTOR IT GETS PINCHED OFF JUST TO THE SOUTH OF OUR FORECAST AREA TONIGHT AS THE SYSTEM OCCLUDES. THE MODELS CONTINUE TO SHOW SOME ELEVATED INSTABILITY WITH SHOWALTER INDICES BELOW ZERO MOVING ACROSS THE REGION TONIGHT...SO THERE IS A CHANCE FOR THUNDERSTORMS HOWEVER CONFIDENCE IS TOO LOW TO INCLUDE IN THE TAFS. CONDITIONS WILL LOWER WITH WIDESPREAD MVFR-IFR DEVELOPING. A GRADUAL IMPROVEMENT WILL OCCUR WITH THE PASSAGE OF THE OCCLUDED FRONT. WITH WIDESPREAD VFR FOR THE AFTERNOON. HAVE NORTHEAST TO SOUTHEAST FLOW ACROSS AREA. RECENT OBSERVATIONS SHOWN A DIMINISHING TREND IN WIND GUSTS ACROSS THE BERKSHIRES... TACONICS AND SOUTHERN VERMONT WHERE THE FLOW HAS BEEN ENHANCED BY THE TERRAIN. WINDS WILL LIGHTEN AS THE OCCLUDED BOUNDARY MOVES THOUGH WITH A SHIFT TO SOUTHWEST TO WEST WITH ITS PASSAGE. WESTERLY WINDS WILL INCREASE TO 10 TO 15 KNOTS AND WILL BE GUSTY ESPECIALLY AT KALB AND KPSF. OUTLOOK... TUE NIGHT-WED: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. WED NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN. THU: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. THU NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. FRI: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. SAT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. && .FIRE WEATHER... THERE ARE NO FIRE WEATHER CONCERNS THIS WEEK AS WE WILL BE UNDER THE INFLUENCE OF AN UPPER LEVEL TROUGH. A WIDESPREAD SOAKING RAINFALL WILL OCCUR ACROSS THE AREA THROUGH TONIGHT...WITH RAINFALL AMTS OF 0.75-1.5 INCHES EXPECTED. THE WEATHER WILL BE COOL AND UNSETTLED FOR MUCH OF THE WEEK. && .HYDROLOGY... A WIDESPREAD SOAKING RAINFALL WILL OCCUR ACROSS THROUGH TONIGHT. EXPECTING WIDESPREAD QPF AMOUNTS OF AROUND AN INCH WITH HIGHER AMOUNTS UP TO AROUND 1.5 INCHES WHERE THE RAINFALL IS ENHANCED BY THE STRONG EAST TO SOUTHEAST FLOW...PARTICULARLY ACROSS THE CENTRAL AND SOUTHEASTERN CATSKILLS...TACONICS...BERKSHIRES INTO THE LITCHFIELD HILLS AND ACROSS SOUTHERN VERMONT. LOCALIZED HIGHER AMOUNTS OF 2 TO 3 INCHES WILL BE POSSIBLE. THERE IS STILL SOME SNOW COVER LEFT IN THE FORECAST AREA. BASED ON NATIONAL OPERATIONAL HYDROLOGIC REMOTE SENSING CENTER (NOHRSC) THIS IS ACROSS THE PORTIONS OF THE WESTERN ADIRONDACKS AND ACROSS THE HIGHER TERRAIN OF THE SOUTHERN GREEN MOUNTAINS. BASED ON CURRENT FORECASTS...ONLY THE WEST CANADA CREEK AT HINCKLEY DAM IS EXPECTED TO EXCEED ITS FLOOD STAGE BY TUESDAY EVENING. THE REST OF THE WEEK THE FORECAST WILL BE DOMINATED BY A PERSISTENT UPPER LEVEL TROUGH WHICH WILL RESULT IN COOL TEMPERATURES...BREEZY CONDITIONS AND OCCASIONAL CHANCES FOR MAINLY LIGHT PRECIPITATION. FOR DETAILS ON SPECIFIC AREA RIVER 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...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...IAA/KL/LFM/11/WASULA NEAR TERM...IAA/LFM/11/WASULA SHORT TERM...11 LONG TERM...IAA AVIATION...IAA/WASULA FIRE WEATHER...11 HYDROLOGY...IAA/KL/11
AREA FORECAST DISCUSSION
NWS ALBANY NY
836 PM EDT MON APR 20 2015 .SYNOPSIS... .A LOW PRESSURE SYSTEM APPROACHING FROM THE WEST WITH ASSOCIATED FRONTS WILL BRING OCCASIONAL SHOWERS TO THE AREA ALONG WITH A FEW RUMBLES OF THUNDER TONIGHT. WITH A LARGE STATIONARY LOW OVER THE REGION...UNSETTLED WEATHER WILL CONTINUE THROUGH THE WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... THE WIND ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT FOR THE HIGHER ELEVATIONS OF THE NORTH AND CENTRAL TACONICS...BERKSHIRES AND FOR BENNINGTON AND WESTERN WINDHAM COUNTIES. HOWEVER RECENT OBSERVATIONS SHOWN A DIMINISHING TREND IN WIND GUSTS. WILL LIKELY BE ABLE TO DROP THE WIND ADVISORY EARLY. HAVE HAD A BIT OF A LULL IN THE PRECIPITATION THIS EVENING. HAVE SHOWERS ACTIVITY OCCURRING TO EAST AND CONVECTION TO OUR WEST IN THE VICINITY OF THE WARM FRONT. HAVE ADJUSTED POPS TO BETTER REFLECT CURRENT ACTIVITY. THE HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON CONVECTION SO HAVE USED IT AS A GUIDE TO INCREASE POPS THIS EVENING AS ANOTHER DISTURBANCE AHEAD AN OCCLUDING FRONTAL BOUNDARY INCREASES THE THREAT FOR CONVECTION. THE SYSTEM WILL OCCLUDE AS IT MOVES EASTWARD. WE ARE NOT EXPECTED TO GET INTO THE WARM SECTOR IT GETS PINCHED OFF JUST TO THE SOUTH OF OUR FORECAST AREA TONIGHT AS THE SYSTEM OCCLUDES. MODELS CONTINUE TO SHOW SOME ELEVATED INSTABILITY WITH SHOWALTER INDICES BELOW ZERO MOVING ACROSS THE REGION TONIGHT...SO HAVE KEEP MENTION OF THUNDER IN THE FORECAST. ANY THUNDERSTORMS THAT OCCUR COULD HAVE LOCALLY HEAVY DOWNPOURS...ESPECIALLY GIVEN THE STRONG THETA-E RIDGE WHICH DEVELOPS ACROSS THE REGION OVERNIGHT. LOWS ARE EXPECTED TO BE IN THE 40S. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... DURING THE DAY ON TUESDAY WE CAN EXPECT SOME LINGERING SHOWERS DURING THE DAY WITH SOME BREAKS OF SUN POSSIBLE IN THE AFTERNOON. THE UPPER LEVEL TROUGH AXIS WILL BE PASSING THROUGH THE AREA WITH AN ASSOCIATED VORT MAX. HIGH TEMPS ON TUESDAY ARE EXPECTED MAX TEMPS ARE FORECAST TO REACH THE LOWER/MID 60S IN VALLEY AREAS AND 50S ACROSS HIGHER ELEVATIONS. FOR TUESDAY NIGHT AND WEDNESDAY...A SECONDARY TROUGH IS EXPECTED TO MOVE FROM THE MIDWEST THROUGH CENTRAL NEW YORK AND CENTRAL PENNSYLVANIA BRINGING ANOTHER ROUND OF SHOWERS AND THIS WILL BE FOLLOWED BY YET ANOTHER TROUGH OF LOW PRESSURE ON WEDNESDAY. THIS IS ALL OCCURRING AT THE SURFACE WHILE ALOFT AN UPPER LEVEL CLOSED LOW SITS AND SPINS JUST NORTH OF THE UPPER GREAT LAKES SENDING PIECES OF ENERGY IN THE FORM OF VORT LOBES ACROSS OUR FA DURING MUCH OF THE PERIOD. EXPECT LOWS ON TUESDAY NIGHT ARE EXPECTED TO RANGE FROM THE UPPER 20S NORTHWEST TO AROUND 40 SOUTHEAST. SOME LIGHT SNOW ACCUMULATIONS GENERALLY UNDER AN INCH ARE POSSIBLE ACROSS THE WESTERN ADIRONDACKS. HIGHS ON WEDNESDAY ARE EXPECTED TO RANGE FROM THE UPPER 40S NORTHWEST TO AROUND 690 NORTHWEST. FOR WEDNESDAY NIGHT AND THURSDAY NOT MUCH IMPROVEMENT IS EXPECTED AS THE UPPER LEVEL TROUGH AXIS SETTLES ACROSS THE NORTHEAST US WHILE AT THE SURFACE LOW PRESSURE INTENSIFIES ACROSS THE GULF OF MAINE WITH YET ANOTHER COLD FRONT EXPECTED TO MOVE INTO THE EASTERN GREAT LAKES BY THURSDAY. THUS THERE WILL STILL BE SCATTERED SHOWERS AROUND ALTHOUGH THE PCPN SHOULD BE MAINLY ON THE LIGHT SIDE. EXPECT LOWS WEDNESDAY NIGHT TO BE IN THE UPPER 20S TO UPPER 30S WITH ONCE AGAIN A LITTLE LIGHT SNOW POSSIBLE ACROSS THE WESTERN ADIRONDACKS WITH HIGHS ON THURSDAY IN THE MID 40S TO LOWER 50S. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... BELOW NORMAL TEMPERATURES ALONG WITH SOME INTERVALS OF RAIN AND EVEN SNOW SHOWERS ARE EXPECTED THROUGH THE WEEKEND. MODEL GUIDANCE REMAINS IN GOOD AGREEMENT INDICATING A LARGE SCALE UPPER LOW WILL DOMINATE OUR WEATHER. HOWEVER THERE CONTINUES TO BE SOME DISAGREEMENT ON ITS EXACT TRACK AND WITH THE TIMING OF INDIVIDUAL SHORT WAVE ROTATING ABOUT IT. THERE IS CONSENSUS THE CENTER OF THE UPPER LOW SHOULD REMAIN TO OUR NORTH AS IT MOVES ACROSS EASTERN CANADA KEEPING OUR THE REGION IN WESTERLY FLOW. HAVE FAVORED GUIDANCE FROM THE WEATHER PREDICTION CENTER TO MAINTAIN FORECAST CONSISTENCY. THE BETTER CHANCES FOR SCATTERED SHOWERS WILL BE ACROSS THE HIGHER TERRAIN. RAIN SHOWERS ARE EXPECTED DURING THE DAY...BUT AT NIGHT IT WILL BE COLD ENOUGH FOR SNOW SHOWER ESPECIALLY ACROSS THE HIGHER ELEVATIONS. OVERALL EXPECTING HIGHS IN THE 40S AND 50S WITH LOWS IN THE 20S AND 30S. NORMALS FOR LATE APRIL... ALBANY NY: HIGHS IN THE LOWER 60S AND LOWS IN THE LOWER 40S. GLENS FALLS NY: HIGHS IN THE LOWER 60S AND LOWS IN THE UPPER 30S. POUGHKEEPSIE NY: HIGHS IN THE MID 60S AND LOWS AROUND 40. BENNINGTON VT: HIGHS IN THE LOWER 60S AND LOWS IN THE UPPER 30S. PITTSFIELD MA: HIGHS IN THE UPPER 50S AND LOWS IN THE MID 30S. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... A LOW PRESSURE SYSTEM WILL OCCLUDE AS IT MOVES ACROSS THE REGION TONIGHT. WE HAVE HAD A BIT OF A LULL IN THE PRECIPITATION THIS EVENING. HAVE SHOWERS ACTIVITY OCCURRING TO EAST AND CONVECTION TO OUR WEST IN THE VICINITY OF THE WARM FRONT. THE HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON CONVECTION SO HAVE USED IT AS A GUIDE TO INCREASE POPS THIS EVENING WITH THE BEST CHANCES AS WE APPROACH MIDNIGHT AS ANOTHER DISTURBANCE AHEAD THE OCCLUDING FRONTAL BOUNDARY WILL INCREASE THE THREAT FOR CONVECTION. WE ARE NOT EXPECTED TO GET INTO THE WARM SECTOR IT GETS PINCHED OFF JUST TO THE SOUTH OF OUR FORECAST AREA TONIGHT AS THE SYSTEM OCCLUDES. THE MODELS CONTINUE TO SHOW SOME ELEVATED INSTABILITY WITH SHOWALTER INDICES BELOW ZERO MOVING ACROSS THE REGION TONIGHT...SO THERE IS A CHANCE FOR THUNDERSTORMS HOWEVER CONFIDENCE IS TOO LOW TO INCLUDE IN THE TAFS. CONDITIONS WILL LOWER WITH WIDESPREAD MVFR-IFR DEVELOPING. A GRADUAL IMPROVEMENT WILL OCCUR WITH THE PASSAGE OF THE OCCLUDED FRONT. WITH WIDESPREAD VFR FOR THE AFTERNOON. HAVE NORTHEAST TO SOUTHEAST FLOW ACROSS AREA. RECENT OBSERVATIONS SHOWN A DIMINISHING TREND IN WIND GUSTS ACROSS THE BERKSHIRES... TACONICS AND SOUTHERN VERMONT WHERE THE FLOW HAS BEEN ENHANCED BY THE TERRAIN. WINDS WILL LIGHTEN AS THE OCCLUDED BOUNDARY MOVES THOUGH WITH A SHIFT TO SOUTHWEST TO WEST WITH ITS PASSAGE. WESTERLY WINDS WILL INCREASE TO 10 TO 15 KNOTS AND WILL BE GUSTY ESPECIALLY AT KALB AND KPSF. OUTLOOK... TUE NIGHT-WED: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. WED NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN. THU: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. THU NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. FRI: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. SAT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. && .FIRE WEATHER... THERE ARE NO FIRE WEATHER CONCERNS THIS WEEK AS WE WILL BE UNDER THE INFLUENCE OF AN UPPER LEVEL TROUGH. A WIDESPREAD SOAKING RAINFALL WILL OCCUR ACROSS THE AREA THROUGH TONIGHT...WITH RAINFALL AMTS OF 0.75-1.5 INCHES EXPECTED. THE WEATHER WILL BE COOL AND UNSETTLED FOR MUCH OF THE WEEK. && .HYDROLOGY... A WIDESPREAD SOAKING RAINFALL WILL OCCUR ACROSS THROUGH TONIGHT. EXPECTING WIDESPREAD QPF AMOUNTS OF AROUND AN INCH WITH HIGHER AMOUNTS UP TO AROUND 1.5 INCHES WHERE THE RAINFALL IS ENHANCED BY THE STRONG EAST TO SOUTHEAST FLOW...PARTICULARLY ACROSS THE CENTRAL AND SOUTHEASTERN CATSKILLS...TACONICS...BERKSHIRES INTO THE LITCHFIELD HILLS AND ACROSS SOUTHERN VERMONT. LOCALIZED HIGHER AMOUNTS OF 2 TO 3 INCHES WILL BE POSSIBLE. THERE IS STILL SOME SNOW COVER LEFT IN THE FORECAST AREA. BASED ON NATIONAL OPERATIONAL HYDROLOGIC REMOTE SENSING CENTER (NOHRSC) THIS IS ACROSS THE PORTIONS OF THE WESTERN ADIRONDACKS AND ACROSS THE HIGHER TERRAIN OF THE SOUTHERN GREEN MOUNTAINS. BASED ON CURRENT FORECASTS...ONLY THE WEST CANADA CREEK AT HINCKLEY DAM IS EXPECTED TO EXCEED ITS FLOOD STAGE BY TUESDAY EVENING. THE REST OF THE WEEK THE FORECAST WILL BE DOMINATED BY A PERSISTENT UPPER LEVEL TROUGH WHICH WILL RESULT IN COOL TEMPERATURES...BREEZY CONDITIONS AND OCCASIONAL CHANCES FOR MAINLY LIGHT PRECIPITATION. FOR DETAILS ON SPECIFIC AREA RIVER 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...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR NYZ054-061. MA...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MAZ001-025. VT...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR VTZ013-014. && $$ SYNOPSIS...IAA/KL/LFM/11/WASULA NEAR TERM...IAA/11/WASULA SHORT TERM...11 LONG TERM...IAA AVIATION...IAA/WASULA FIRE WEATHER...11 HYDROLOGY...IAA/KL/11
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
345 PM EDT SUN APR 19 2015 .DISCUSSION... TONIGHT...SOUTHERN EDGE OF CONVECTIVE BAND MOVING INTO NE GULF AND NORTH FL HAS BEEN WEAKENING RECENTLY AND HRRR/WRF MODELS INDICATE THIS TREND WILL CONTINUE. HOWEVER SOME PRECIP/EMBEDDED STORM ACTIVITY FROM THIS BAND MAY REACH LAKE COUNTY TOWARD SUNSET. AHEAD OF THIS LINE HRRR CONTINUES TO SHOW SOME ISO/SCT STORMS FORMING ESPECIALLY NEAR THE COAST FROM BOUNDARY COLLISIONS WITH THE EAST COAST SEA BREEZE. LATEST SFC OBS SHOW THE SEA BREEZE HAS BEEN ABLE TO HOLD ON RIGHT ALONG THE COAST AT SOME LOCATIONS. HOWEVER AN INCREASING LOW LEVEL S/SW FLOW INTO LATE DAY MAY PUSH WHAT SEA BREEZE REMAINS OFFSHORE. IF SO CONVECTIVE ACTIVITY MAY BE LIMITED INTO THIS EVENING. FOR NOW WILL HOLD ONTO A CHANCE FOR STORMS INTO THE EVENING MAINLY ALONG THE COAST. IF ANY BOUNDARY COLLISIONS DO OCCUR ISO STRONG STORMS NOT OUT OF THE QUESTION. RAIN CHANCES END BY MIDNIGHT WITH ANY SHOWERS/STORMS PUSHING OFFSHORE. OVERNIGHT LOWS WILL BE IN THE UPPER 60S TO LOW 70S. MONDAY...MODELS SHOW ANOTHER MID LEVEL S/W PUSHING THROUGH THE NRN GULF AHEAD OF WEAK FRONT MOVING INTO THE SOUTHEAST STATES. THIS DISTURBANCE WILL LIKELY LEAD TO ANOTHER BAND OF CONVECTION DEVELOPING OVER THE CENTRAL/EASTERN GULF SHIFTING EASTWARD TOWARD THE FL PENINSULA IN THE EARLY MORNING HOURS. NAM AND TO A DEGREE THE WRF SHOW THIS BAND DEVELOPING FARTHER NORTH AND PUSHING ACROSS MUCH OF THE REGION INTO THE AFT WHILE THE GFS/ECMWF KEEP GREATEST RAIN CHANCES/MOISTURE SOUTH OF ORLANDO. HAVE LEANED TOWARD A BLEND FOR NOW WHICH KEEPS RAIN CHANCES FAIRLY CONSISTENT AROUND 50-60 PERCENT. SOME STRONG TO ISO SEVERE STORMS POSSIBLE IF ENOUGH HEATING CAN OCCUR OUT AHEAD OF ANY CONVECTION OVER THE GULF. MAIN THREAT WOULD BE STRONG WIND GUSTS AND HAIL. TUE...A COOL FRONT WILL SETTLE SOUTH ACROSS CENTRAL FL BRINGING SOME DRIER AIR AND TEMPERATURES MORE SEASONABLE FOR THIS TIME OF YEAR IN THE LOW TO MID 80S. HAVE LOWERED RAIN CHANCES ACROSS THE NORTH TO 20 PERCENT NORTH OF ORLANDO AND THIS MAY BE GENEROUS. MOISTURE LINGERING ACROSS THE SOUTH WILL KEEP RAIN CHANCES 40 TO 50 PERCENT FROM OKEECHOBEE TO THE TREASURE COAST. REST OF WEEK (PREVIOUS)...DEPARTURE OF STRONG UPR WIND MAXIMA WL BRING EVOLUTION TO ZONAL PATTERN WITH BROAD WEAK HIGH DOWNSTREAM ACTING TO STABILIZE AIRMASS...WITH SOME DRYING AS WELL OVER THE NORTH AT MIDWEEK. AFTERNOON BOUNDARY INTERACTION AND SUFFICIENT LL MOISTURE WL FORCE SOME SHOWERS AND SLOW MOVING STORMS WED-THU WITH AT LEAST MENTIONABLE RAIN CHCS IN THE EXTENDED FCST LACKING ANY NOTABLE PATTERN CHG AND OR DRYING OF THE AMBIENT AIRMASS. && .AVIATION... TEMPO IFR/MVFR CONDS IN ISO/SCT SHRA/TSRA MAINLY TOWARD THE COAST WILL OCCUR AHEAD OF APPROACHING BAND OF CONVECTION THAT IS WEAKENING OVER THE NE GULF. THIS BAND MAY REACH AREAS WEST OF I-4 TOWARD SUNSET...PRODUCING ADDITIONAL REDUCTIONS TO CIG/VIS MAINLY AT KLEE. CONVECTION THEN DIMINISHING/PUSHING OFFSHORE INTO LATE EVENING WITH MAINLY VFR OVERNIGHT. DEEP MOISTURE AND AN APPROACHING DISTURBANCE ALOFT WILL KEEP HIGH RAIN CHANCES IN THE FORECAST FOR TOMORROW WITH SCT-NMRS SHRA/TSRA PRODUCING TEMPO IFR/MVFR CONDS INTO THE AFT. && .MARINE... TONIGHT-MONDAY...S/SW WINDS UP TO 10-15 KNOTS WILL BECOME MORE W/SW INTO LATE MON AS A WEAK FRONTAL BOUNDARY PUSHES INTO THE SOUTHEAST STATES. SEAS WILL REMAIN AROUND 2-4 FEET. MAIN CONCERN WILL CONTINUE TO BE FOR OFFSHORE MOVING STORMS THIS EVENING AND TOMORROW AFT/EVE... PRODUCING STRONG GUSTY WINDS. TUE-THU...WEAK FRONT PROGGED TO MOVE DOWN THE FL PENINSULA TUE SO WIND FLOW WILL BE W/NW 10 KNOTS. FLOW BEHIND THE FRONT MID WEEK WILL BECOME ONSHORE AROUND 10 KNOTS. SEAS WILL REMAIN 4 FEET OR LESS. && .PRELIMINARY POINT TEMPS/POPS... DAB 69 84 68 80 / 40 40 20 20 MCO 70 87 69 83 / 20 50 20 30 MLB 71 87 70 82 / 40 60 30 30 VRB 70 87 70 83 / 40 60 30 50 LEE 70 84 68 82 / 20 50 20 20 SFB 70 85 69 83 / 30 50 20 20 ORL 71 86 69 83 / 20 50 20 30 FPR 69 87 70 83 / 40 60 30 50 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM...WEITLICH LONG TERM....KELLY
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
127 PM EDT SUN APR 19 2015 ...TORNADO WATCH TIL 8PM I-10 CORRIDOR NORTHWARD... ...POTENTIAL FOR A FEW STRONG/SEVERE STORMS AGAIN MONDAY... .NEAR TERM...THROUGH TONIGHT... WATER VAPOR SHOWING AN IMPRESSIVE SHORTWAVE THAT WILL MOVE EASTWARD TOWARD AND OVER FORECAST AREA THROUGH THIS EVENING. BAND OF SHOWERS AND EMBEDDED THUNDERSTORMS WILL ACCOMPANY WAVE THIS AFTERNOON. SUFFICIENT INSTABILITY AND DEEP-LAYER SHEAR AHEAD OF SYSTEM TO SUPPORT A FEW STRONG OR SEVERE STORMS EMBEDDED WITHIN THE LINE...MAINLY BOWING LINE SEGMENTS WITH DAMAGING WIND POTENTIAL...THOUGH AN ISOLATED TORNADO IS ALSO POSSIBLE. IN ADDITION...STARTING TO SEE CONVECTION BREAK OUT AHEAD OF SYSTEM OVER OUR WRN COUNTIES. GIVEN THE ENVIRONMENT IN PLACE...THERE IS POTENTIAL FOR A FEW DISCRETE STRONG/SEVERE CELLS TO DEVELOP THIS AFTERNOON. LATEST HRRR SUGGESTS THIS ACTIVITY COULD INTENSIFY AS IT SPREADS NORTHEAST OVER THE NEXT FEW HOURS. TORNADO WATCH IS IN EFFECT FOR AREAS FROM THE I-10 CORRIDOR NORTHWARD TIL 8PM. BAND OF SHOWERS/STORMS WILL MOVE QUICKLY NORTH AND EAST ACROSS FORECAST AREA BETWEEN 2PM AND 7PM...THEN MOVE OFFSHORE. LOW TEMPS EXPECTED TO BE 68-70 MOST LOCATIONS. SHORT TERM...MONDAY THROUGH TUESDAY NIGHT... FOR MONDAY...COLD FRONT APPROACHES FROM THE NORTHWEST. MORE WESTERLY FLOW AT LOW AND MID LEVELS BRINGS IN DRIER AIR...AND AS A RESULT THE MODELS DEVELOP CONSIDERABLY LESS PRECIP COVERAGE MONDAY AFTERNOON COMPARED TO THIS AFTERNOON. WILL MAINTAIN 30-40 POP FOR MONDAY AFTERNOON. ONCE AGAIN SPC HAS SLIGHT RISK OF SEVERE STORMS OVER OUR AREA...AND ONCE AGAIN WE SHOULD HAVE FAVORABLE COMBINATION OF MODERATE CAPE AND SUFFICIENT DEEP LAYER SHEAR. LOW-LEVEL WINDS WILL BE MORE SW AHEAD OF COLD FRONT...AND THIS WILL REDUCE HELICITY...SO PRIMARY THREAT WILL BE STRONG WINDS. WARM AGAIN MONDAY WITH HIGHS IN THE MID 80S ACROSS THE FORECAST AREA. COLD FRONT MOVES ACROSS THE AREA LATE MONDAY NIGHT...WITH SOMEWHAT COOLER DRIER CONDITIONS TUESDAY. CURRENT FORECAST HIGH TEMPS OF UPPER 70S SE GA...AROUND 80 I-10 CORRIDOR...AND LOW 80S GNV/OCF LOOKS FINE. COOLER NIGHT TUESDAY NIGHT WITH LOW TEMPS 55-60 ACROSS THE AREA...EXCEPT LOW 60S COAST. LONG TERM...WEDNESDAY THROUGH SUNDAY... GIVEN THE HIGH IMPACT THREATS THROUGH MONDAY...DID NOT MAKE SIGNIFICANT CHANGES TO THE MEDIUM RANGE GIVEN NOT MUCH SIGNIFICANT CHANGE IN LATEST MODEL GUIDANCE. STILL EXPECT WEAK SURFACE RIDGING AND ZONAL FLOW ALOFT THROUGH THE END OF THE WORKWEEK...WITH SOME INCREASE IN TEMPS AS WELL AS SLIGHT CHANCES FOR SHOWERS WITH SEA BREEZES. BETTER RAIN CHANCES MAY STILL COME OVER WEEKENDD... THOUGH SOME UNCERTAINTY AS TO TRACK OF NEXT WEEK SYSTEM AND WHERE THE MORE WIDESPREAD PRECIPITATION WILL END UP. && .AVIATION...MAIN SQUALL LINE WELL WEST OF THE LOCAL FIELDS WITH GAINESVILLE MOST LIKELY TO FEEL ITS IMPACT. EXPECT CONVECTION TO MOVE IN THERE BETWEEN 19-21 UTC WITH CEILINGS IN THE 2.5 KFT RANGE. THE COAST FIELDS FROM SAINT AUGUSTINE THROUGH THE JACKSONVILLE METRO AREA TO SAINT SIMONS ISLAND SHOULD SEE A CONVERGENCE BETWEEN THE DOMINANT SOUTHWESTERLY LOW LEVEL FLOW PATTERN AND THE DEVELOPING ATLANTIC SEA BREEZE FRONT. EXPECT STRONG TO POSSIBLY SEVERE CONVECTION TO FIRE UP ALONG THE ATLANTIC COAST WITH CEILINGS BETWEEN 2.5-5 KFT. THESE STORMS SHOULD PASS OFFSHORE THIS EVENING BY 23OO UTC AS THE WEAKENING SQUALL LINE MAKES ITS RUN AT THE COAST. && .MARINE....WINDS WILL GRADUALLY INCREASE AND VEER OUT AHEAD OF APPROACHING COLD FRONT ALTHOUGH NO HEADLINES EXPECTED THRU MONDAY. THE COLD FRONT CROSSES THE WATERS MONDAY NIGHT BRINGING A BRIEF PERIOD OF CONDITIONS APPROACHING ADVISORY CRITERIA IN THE OFFSHORE COMPONENT. SCATTERED TO NUMEROUS AFTERNOON AND EVENING SHOWERS/TSMS THRU MONDAY... WITH STRONG WINDS POSSIBLE WITH THE MORE INTENSE STORMS. HIGH PRESSURE QUICKLY BUILDS IN BEHIND THE FRONT TUE WITH WIND/SEAS DECREASING FOR REMAINDER OF WEEK. .RIP CURRENTS...MODERATE RISK THIS AFTERNOON...LOW RISK MONDAY. && .PRELIMINARY POINT TEMPS/POPS... AMG 67 85 60 77 / 30 30 20 10 SSI 69 82 65 75 / 30 30 20 10 JAX 69 85 64 79 / 30 30 20 10 SGJ 70 83 67 77 / 30 40 20 10 GNV 68 85 65 81 / 20 40 20 10 OCF 69 85 66 82 / 20 40 20 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...NONE. && $$ WOLF/SANDRIK/WALKER
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
901 AM EDT SUN APR 19 2015 ...INCREASING POTENTIAL FOR STRONG/SEVERE STORMS THIS AFTERNOON... .UPDATE... INTERESTING ENVIRONMENTAL SETUP FOR THIS AFTERNOON IN OUR AREA. INITIAL PRECIPITATION AREA EXITING TO NORTHEAST WITH INITIAL SHORTWAVE SEEN ON WATER VAPOR IMAGERY. VISIBLE IMAGERY SHOWING AREA OF CLEARING...JUST SOME HIGH CLOUDS...SOUTHWEST GA/NW AND WCTRL FL WHICH WILL SHIFT EASTWARD AHEAD OF DEVELOPING CONVECTION OVER GULF OF MEX. THUS SHOULD ALLOW SURFACE TEMPS TO RISE INTO 80-85 RANGE ACROSS FCST AREA...DESTABILIZING AIRMASS. GENERALLY FOLLOWING THE HRRR...ANTICIPATE INCREASE/UPSCALE IN CONVECTION W OF FORECAST AREA INTO NRN GULF THROUGH THE MORNING APPROACHING OUR WRN COUNTIES TOWARD 18Z...AHEAD OF A WELL-DEFINED SHORTWAVE SEEN ON WATER VAPOR. MODELS BRING SHORT WAVE OVER OUR FORECAST AREA LATE THIS AFTERNOON. MEANWHILE...MORNING SOUNDINGS SUGGEST POTENTIAL FOR EAST COAST SEA BREEZE TO MAKE SOME PROGRESS INLAND...PERHAPS TO I-95 CORRIDOR MID AFTERNOON WHILE WEST COAST SEA BREEZE MOVES EASTWARD DURING AFTERNOON. LATEST HRRR SUGGESTS TWO AREAS OF CONCERN...FIRST IS AN ORGANIZED LINE...OR LINE SEGMENTS...MOVING NORTHEAST ACROSS OUR WESTERN COUNTIES 18Z-21Z...AND EASTERN COUNTIES 21Z-00Z. PRIMARY THREAT WILL BE LOCALLY SEVERE WINDS WITH BOWING SEGMENTS GIVEN UNSTABLE AIRMASS AND DECENT LOW-LEVEL LAPSE RATES. FEEL THE BEST POTENTIAL FOR SEVERE WEATHER FROM THIS PORTION WILL BE SUWANNEE VALLEY REGION OF NE FL...AND MUCH OF SE GA. SUFFICIENT LOW-LEVEL SHEAR/HELICITY SUCH THAT ISOLATED TORNADOES WILL BE POSSIBLE. A TORNADO WATCH IS ISSUED WEST OF OUR AREA...AND WOULD ANTICIPATE EASTWARD EXPANSION THIS AFTERNOON. HRRR SUGGESTS WEAKENING OF THIS ACTIVITY AS IT MOVES EAST OVER OUR FORECAST AREA...BUT UNCERTAIN OF THIS SOLUTION GIVEN WELL DEFINED SHORT WAVE AND DIFFLUENCE IN RIGHT-REAR QUAD SUPPORTING CONVECTION. A SECOND AREA OF CONCERN IS ASSOCIATED WITH EASTWARD MOVING WEST COAST SEA BREEZE...WHICH HRRR SUGGESTS COULD INITIATE DISCRETE CELLULAR CONVECTION AFTER 18Z OVER EASTERN PORTION OF NE FL... PARTICULARLY LATER IN AFTERNOON AS IT CONVERGES WITH EAST COAST SEA BREEZE. COMBINATION OF CAPE VALUES 2000-3000 J/KG AND DEEP LAYER SHEAR VALUES NEAR 40KTS SUGGEST SOME SUPERCELL STRUCTURES POSSIBLE...WITH POTENTIAL FOR ISOLATED STRONG/SEVERE STORMS. PRIMARY THREAT HERE WOULD BE STRONG WINDS AND HAIL...BUT CANNOT RULE OUT ISOLATED TORNADO ESPECIALLY FAR EASTERN COUNTIES IF FLOW IS BACKED NEAR EAST COAST SEA BREEZE. && .AVIATION...VFR CONDITIONS THRU EARLY AFTERNOON...WITH POTENTIAL FOR MVFR CONDITIONS ASSOCIATED WITH SCATTERED TO NUMEROUS TSRA. && .MARINE...NO SIGNIFICANT CHANGES PLANNED IN NEXT CWF ISSUANCE. WINDS WILL BECOME SOUTH TODAY WITH 2-4 FT SEAS. SHOWERS/T-STORMS WILL INCREASE DURING THE AFTERNOON INTO THE EARLY EVENING HOURS. RIP CURRENTS: MODERATE RISK TODAY DUE TO LINGERING SWELL. && .PRELIMINARY POINT TEMPS/POPS... AMG 82 65 82 58 / 80 30 30 20 SSI 79 68 81 64 / 80 30 30 20 JAX 84 67 84 62 / 80 30 30 20 SGJ 82 68 82 65 / 70 30 40 20 GNV 85 67 83 64 / 70 20 40 20 OCF 86 67 83 65 / 60 20 40 20 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...NONE. && $$ WOLF/SANDRIK/WALKER
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
939 PM EDT MON APR 20 2015 .SYNOPSIS... A COLD FRONT WILL CROSS THE AREA LATE TONIGHT. DRIER HIGH PRESSURE WILL BUILD IN TUESDAY AND WEDNESDAY. A WEAK COLD FRONT WILL DROP THROUGH THE AREA THURSDAY NIGHT...THEN WILL STALL TO THE SOUTH. A STORM SYSTEM WILL AFFECT THE REGION FRIDAY NIGHT THROUGH SATURDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST SUNDAY INTO MONDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 21/01Z MESOANALYSIS PLACED THE COLD FRONT FROM THE WESTERN NORTH CAROLINA PIEDMONT INTO THE SOUTH CAROLINA UPSTATE AND EXTENDING SOUTHWEST TO NEAR COLUMBUS GEORGIA. ISOLATED STRONG TO SEVERE TSTMS CONTINUE TO FIRE ALONG AND JUST AHEAD OF THE FRONT AS INCREASING 0-6KM BULK SHEAR COUPLED WITH INTENSIFYING UPPER FORCING ASSOCIATED WITH LEFT EXIT REGION OF A 140 JET JET STREAK COMPENSATE FOR WANING SURFACE BASED INSTABILITY. THE H3R HAS SHOWN REMARKABLE RUN-TO-RUN CONSISTENCY IN REDEVELOPING ISOLATED TO PERHAPS LOW-END SCATTERED CONVECTION ACROSS EAST-CENTRAL GEORGIA AND CSRA ALONG THE FRONT AS THE CORE OF THE MOST INTENSE UPPER FORCING TRAVERSES THE AREA OVER THE NEXT 3-5 HOURS. THE 21/00Z KCHS RAOB SHOWED A STRONG CAPPING INVERSION AT 872 HPA...WHILE WEST OF THE I-95 CORRIDOR RAP SOUNDINGS DEPICTED CONSIDERABLY LESS CAPPING WITH MLCAPE HOLDING 500-700 J/KG THROUGH ABOUT 2 AM. SUSPECT THIS WILL BE ENOUGH TO SUSTAIN ANY UPSTREAM FORCED CONVECTION FOR SEVERAL MORE HOURS... BEFORE WEAKENING AS IT APPROACHES THE COAST. WILL HIGHLIGHT SLIGHT CHANCE POPS ALONG AND JUST AHEAD OF THE FRONT FOR ALL AREAS. STILL CAN NOT RULE OUT AN ISOLATED STRONG TO SEVERE TSTM GIVEN THE AMOUNT OF BULK SHEAR AND DCAPE IN PLACE WITH DAMAGING WIND GUSTS BEING THE PRIMARY HAZARD. LOWS FROM THE UPPER 50S FAR INTERIOR SOUTHEAST GEORGIA TO THE MID 60S AT THE COAST LOOK REASONABLE. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... TUESDAY AND WEDNESDAY...SURFACE HIGH PRESSURE CENTERED OVER THE GULF COAST STATES WILL EDGE EASTWARD AND EXPAND OVER THE AREA. ALOFT...FLOW WILL REMAIN NEARLY ZONAL BETWEEN A LOW SPINNING OVER EASTERN CANADIAN AND SUBTROPICAL RIDGE TO OUR SOUTH. COOLER AND MUCH DRIER AIRMASS WILL TAKE HOLD...AND WITH SUBSIDENCE NOTED IN MODEL SOUNDINGS BOTH DAYS SHOULD BE PRECIP-FREE. WEAK DOWNSLOPE FLOW WILL HELP HIGHS REACH THE UPPER 70S TUESDAY...UPPER 70S/LOW 80S ON WEDNESDAY. LOWS TUESDAY NIGHT WILL BE IN THE LOW 50S...WHILE WEDNESDAY NIGHT IS MORE MILD WITH INCREASING CLOUD COVER IN THE LOW 60S. WEDNESDAY NIGHT INTO THURSDAY...SURFACE HIGH WILL SHIFT INTO THE ATLANTIC AHEAD OF A WEAK COLD FRONT APPROACHING FROM THE NORTHWEST. THE FRONT WILL CROSS THROUGH THE FORECAST ON THURSDAY EVENING. DESPITE A PASSING SHORTWAVE...MOISTURE IS NOT OVERLY IMPRESSIVE. GIVEN THAT MODELS ARE STILL PRETTY INCONSISTENT ON QPF DURING THIS TIME FRAME WITH THE EURO NEARLY DRY/GFS THE WETTER SOLUTION...HAVE OPTED TO CAP POPS BELOW 15 PERCENT FOR NOW. HIGHS WILL BE IN THE UPPER 70S/LOW 80S. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... A BACK DOOR COLD FRONT WILL DROP THROUGH THE AREA THURSDAY NIGHT AND FRIDAY...BRIEFLY STALLING TO THE SOUTH. FRIDAY TENTATIVELY LOOKS DRY WITH HIGHS IN THE MID/UPPER 70S. INCREASING UPPER SHORTWAVE ENERGY FRIDAY NIGHT INTO SATURDAY WILL ALLOW THE FRONT TO LIFT NORTH WITH A LOW PRESSURE SYSTEM LIFTING INTO THE MID-ATLANTIC REGION. A COLD FRONT WILL PUSH THROUGH SATURDAY OR SATURDAY NIGHT WITH WEAK HIGH PRESSURE BUILDING IN SUNDAY. THERE ARE SIGNIFICANT MODEL DIFFERENCES REGARDING PRECIPITATION POTENTIAL DURING THE PERIOD. WE MAINTAINED THE HIGHEST POPS DURING THE DAY SATURDAY...DECREASING SATURDAY NIGHT. BELOW-NORMAL TEMPS EXPECTED SUNDAY AND MONDAY AS HIGH PRESSURE LINGERS TO THE NORTH. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... VFR. HIGH RESOLUTION MODELS SUGGEST A BROKEN LINE OF SHOWERS AND TSTMS COULD MOVE ACROSS THE TERMINALS 04-07Z...BUT CONFIDENCE IS QUITE LOW. WILL NOT INCLUDE A MENTION SHRA/TSRA ATTM. EXTENDED AVIATION OUTLOOK...LOW STRATUS OR FOG POSSIBLE AROUND DAYBREAK THURSDAY AND FRIDAY MORNINGS. && .MARINE... OVERNIGHT...A TIGHT PRESSURE GRADIENT BETWEEN A MESO-HIGH INDUCED BY SEVERE CONVECTION OVER FLORDIA AND THE APPROACHING COLD FRONT HAS BEEN SUPPORTING WIND GUSTS OVER 30 KT AT BOTH BUOY 41004 AND 41008 OVER THE PAST FEW HOURS. ELEVATED WINDS WILL PERSIST ACROSS THE GEORGIA NEARSHORE WATERS FOR A FEW MORE HOURS...SO EXPANDED THE SMALL CRAFT ADVISORY THERE UNTIL 2 AM. THE ADVISORY FOR THE GEORGIA OFFSHORE WATERS REMAINS IN EFFECT UNTIL 8 AM. WINDS WILL REMAIN 15-20 KT OVER THE SOUTH CAROLINA WATERS WITH 10 KT IN THE CHARLESTON HARBOR. SEAS WILL AVERAGE 2-4 FT NEARSHORE WATERS AND 4-5 FT OFFSHORE WATERS. TUESDAY THROUGH SATURDAY...CONDITIONS WILL REMAIN RATHER BENIGN OVER THE MARINE ZONES. SURFACE HIGH PRESSURE WILL EXPAND OVER THE WATERS TUESDAY BEHIND THE DEPARTING COLD FRONT...ALLOWING THE PRESSURE GRADIENT TO RELAX. THE HIGH WILL THEN SHIFT EAST INTO THE ATLANTIC WEDNESDAY INTO THURSDAY AHEAD OF A WEAK COLD FRONT APPROACHING FROM THE NORTHWEST. THE FRONT IS EXPECTED TO CROSS THROUGH THE WATERS THURSDAY NIGHT. ANOTHER STORM SYSTEM EXPECTED TO APPROACH SATURDAY. WEAK PRESSURE GRADIENT WILL KEEP WINDS AT OR BELOW 15 KTS ON AVERAGE WITH SEAS 2-4 FEET HIGHEST IN THE OUTER WATERS...WELL BELOW SMALL CRAFT ADVISORY CRITERIA. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR AMZ374. SMALL CRAFT ADVISORY UNTIL 2 AM EDT TUESDAY FOR AMZ354. && $$ ST
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
425 PM EDT SUN APR 19 2015 .SYNOPSIS... A COLD FRONT WILL APPROACH THE AREA MONDAY. THE FRONT WILL CROSS THE REGION MONDAY NIGHT AND WILL SHIFT OFFSHORE BY EARLY TUESDAY. HIGH PRESSURE WILL THEN PREVAIL TUESDAY INTO THURSDAY. A WEAK COLD FRONT WILL DROP THROUGH THE AREA THURSDAY NIGHT...THEN WILL STALL JUST SOUTH OF THE REGION LATE WEEK. A STORM SYSTEM WILL AFFECT THE REGION NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... REST OF THE AFTERNOON AND EVENING...THUNDERSTORMS ARE CURRENTLY PROGRESSING THROUGH SOUTHEAST GEORGIA AND THE TORNADO WATCH HAS BEEN EXPANDED TO INCLUDE CHARLESTON COUNTY...BERKELEY COUNTY...CHARLESTON HARBOR...AND AMZ350. THE ENVIRONMENT HAS SET UP MUCH LIKE WAS ANTICIPATED THIS MORNING. TEMPERATURES ACROSS SOUTHEAST GEORGIA HAVE WARMED INTO THE LOW 80S IN MANY AREAS WITH DEW POINTS IN THE LOW 70S. SURFACE BASED CAPE VALUES ARE IN THE 2000-2500 J/KG RANGE AND 0-3 KM SHEAR IS ON THE ORDER OF 30-35 KT. THE NEAR SURFACE FLOW IS BACKED TO MORE SOUTHEASTERLY WHICH IS ENHANCING THE STORM RELATIVE HELICITY VALUES INTO THE 200 RANGE. CURRENT RADAR TRENDS SHOW LINEAR CONVECTION JUST TO THE WEST WITH MORE DISCRETE CELLULAR DEVELOPMENT FURTHER SOUTH ACROSS THE NORTHERN EXTENT OF JAX/S FORECAST AREA. THE CONVECTIVE MODE WILL CONTINUE TO FAVOR LINEAR SEGMENTS AND WITH THE SHEAR/INSTABILITY COMBINATION EMBEDDED SUPERCELL ELEMENTS ARE EXPECTED. HI-RES MODEL RUNS SUCH AS THE HRRR CONTINUE TO SHOW AN ELEVATED MIXED LAYER SIGNATURE IN THE SOUNDINGS. DAMAGING WINDS CONTINUE TO BE THE PRIMARY THREAT...THOUGH LARGE HAIL CANNOT BE TOTALLY RULED OUT. THERE ALSO REMAINS THE THREAT OF BRIEF TORNADOES SPINNING UP WITHIN ANY QLCS SEGMENTS. TIMING IS LARGELY UNCHANGED...WITH THE CONVECTION REACHING THE SAVANNAH METRO AREA RIGHT NOW AND THEN WILL REACH THE CHARLESTON AREA AROUND 22Z-23Z. TONIGHT...THE LINE OF CONVECTION WILL PUSH EAST OF THE AREA AND OFFSHORE RIGHT AROUND MIDNIGHT. THEREAFTER...MODEL TIME HEIGHTS AND SOUNDING SHOWS NOTABLE MID/UPPER LEVEL DRYING AND THE REMAINDER OF THE NIGHT IS EXPECTED TO BE DRY. STRATUS WILL FILL IN OVERNIGHT AND OVERCAST SKIES WILL PREVAIL. ANOTHER VERY WARM NIGHT IS EXPECTED...WITH YET ANOTHER PERSISTENCE FORECAST FOR LOWS. THE FORECAST FEATURES MID TO UPPER 60S AGAIN. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... THE UPSTREAM LONGWAVE TROUGH WILL PUSH A STRONG COLD FRONT TOWARD THE REGION MONDAY. AFTER A RAIN-FREE MORNING...THE CHANCE FOR THUNDERSTORMS WILL INCREASE DURING THE AFTERNOON. DESTABILIZATION SUPPORTED BY FEATURING MLCAPES INCREASING TO 2000-3000 J/KG...FAIRLY UNIDIRECTIONAL 0-6 KM BULK SHEAR 40-50 KNOTS AND SOME DYNAMIC FORCING FOR ASCENT PROVIDED BY AN APPROACHING SHORTWAVE TROUGH ALOFT/LARGE SCALE HEIGHT FALLS PRODUCED BY THE PARENT LONGWAVE TROUGH WILL SUPPORT THE POTENTIAL FOR ANOTHER ROUND OF ORGANIZED THUNDERSTORMS PRODUCING SEVERE WEATHER. DOWNDRAFT CAPES AROUND 1500 J/KG AND DRIER AIR ALOFT WILL SUPPORT DAMAGING WIND GUSTS AND EVEN LARGE HAIL. THUNDERSTORM COVERAGE REMAINS UNCERTAIN MONDAY AFTERNOON/EVENING. WHILE ORGANIZED THUNDERSTORMS COULD PUSH INTO THE REGION FROM THE WEST...STRONG THUNDERSTORMS SOUTH OF THE REGION COULD LIMIT COVERAGE OVER THE REGION. ALSO POSSIBLE...STRONGEST THUNDERSTORMS COULD REMAIN JUST NORTH OF THE REGION. FOR NOW...CAPPED POPS AT 50 PERCENT OR LESS...HIGHEST INLAND/NORTH...BUT ADJUSTMENTS COULD YET BE REQUIRED. WILL CONTINUE TO HIGHLIGHT THE SEVERE WEATHER THREAT WITHIN THE HAZARDOUS WEATHER OUTLOOK. THE COLD FRONT WILL CROSS THE REGION MONDAY NIGHT. THE CHANCE FOR THE SHOWERS/THUNDERSTORMS WILL GRADUALLY WANE...AND THE POTENTIAL FOR SEVERE WEATHER WILL ALSO DIMINISH WITH DIURNAL STABILIZATION. MUCH DRIER HIGH PRESSURE WILL PREVAIL TUESDAY AND WEDNESDAY. HIGHS WILL AVERAGE IN THE MID TO UPPER 70S...AND LOWS IN THE 50S WILL BE COMMON TUESDAY NIGHT. GUIDANCE PULLS VARYING DEGREES OF MID/HIGH LEVEL MOISTURE INTO THE REGION WITHIN A ZONAL FLOW AHEAD OF AN APPROACHING COLD FRONT WEDNESDAY. WHILE CLOUD COVER SHOULD INCREASE...CONVECTIVE PRECIPITATION PRODUCED BY THE GFS APPEARS OVERDONE. THUS...HELD POPS BELOW 15 PERCENT WITH NO MENTION OF PRECIPITATION WEDNESDAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... A ZONAL PATTERN WILL EXIST MUCH OF THE PERIOD. A WEAK BACK DOOR COLD FRONT DROPS THROUGH THE AREA THURSDAY NIGHT. THE FRONT WILL STALL TO THE SOUTH BEFORE LIFTING BACK NORTH AS A WARM FRONT FRIDAY NIGHT AND SATURDAY. A PRONOUNCED SHORTWAVE EMBEDDED IN THE QUASI-ZONAL FLOW WILL MOVE THROUGH SATURDAY NIGHT ACCOMPANIED BY A COLD FRONT. PRECIPITATION POSSIBLE STARTING FRIDAY NIGHT AND CONTINUING INTO SATURDAY NIGHT. TEMPS WILL BE MODERATED BY INCREASING CLOUD COVER AND WEAK COLD ADVECTION. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... MVFR CEILINGS HAVE RETURNED TO BOTH TERMINALS EARLY THIS AFTERNOON AND THE MAIN FORECAST ISSUE THROUGH THE EVENING WILL BE TIMING THUNDERSTORMS INTO THE FORECAST. BASED ON CURRENT RADAR TRENDS AND HI-RES MODEL GUIDANCE...IT LOOKS LIKE THUNDER WILL REACH KSAV AND IMPACT THE TERMINAL BETWEEN 20Z-22Z. HAVE GONE WITH IFR CONDITIONS IN THUNDER WITH GUSTY WINDS TO ALMOST 40 KT BASED ON SOME UPSTREAM OBSERVATIONS. AT KCHS...THUNDER WILL ARRIVE LATER AND IT IS UNCLEAR IF IT WILL BE AS STRONG AS IT IS EXPECTED AT KSAV. HAVE GONE WITH 22Z-00Z AT KCHS WITH IFR CONDITIONS AND SLIGHTLY LESSER WIND GUSTS. ONCE THE CONVECTION MOVE EAST OF THE TERMINALS THERE WILL BE A BIT OF A LULL UNTIL IFR CEILINGS ARE PROGGED TO RETURN AFTER MIDNIGHT. BOTH SITES GET PREVAILING IFR CEILINGS THROUGH THE LATE NIGHT...SCATTERING OUT MONDAY MORNING. EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS WITHIN SCATTERED SHOWERS/TSTMS POSSIBLE AT BOTH TERMINALS MONDAY AFTERNOON AND EVENING. OTHERWISE...VFR THROUGH THE PERIOD. && .MARINE... THIS EVENING AND TONIGHT...THE MAIN FORECAST ISSUE WILL BE THE LINE OF THUNDERSTORMS EXPECTED TO MOVE THROUGH THE LOCAL WATERS THIS EVENING AND THE FIRST PART OF TONIGHT. THESE STORMS COULD BE QUITE STRONG...PRODUCING 35 KT OR GREATER WINDS GUSTS...FREQUENT LIGHTNING...AND EVEN THE POTENTIAL FOR A TORNADIC WATERSPOUT. THE STORMS WILL IMPACT THE GEORGIA AND SOUTHERN SOUTH CAROLINA WATERS THROUGH ABOUT 10 PM...AND THEN MOVE OFF THE CHARLESTON COUNTY WATERS JUST AFTER MIDNIGHT. OTHERWISE...SOUTHERLY FLOW WILL PREVAIL AND THEN TURN MORE SOUTHWESTERLY LATE. OUTSIDE OF CONVECTION WINDS WILL TOP OUT IN THE 15-20 KT RANGE AND NO SMALL CRAFT ADVISORIES ARE ANTICIPATED. AHEAD OF AN APPROACHING COLD FRONT...SMALL CRAFT ADVISORY GUSTS FROM THE SOUTHWEST ARE POSSIBLE MONDAY AND MONDAY EVENING...ESPECIALLY ACROSS NEARSHORE WATERS. HOWEVER...SINCE THIS EVENT APPEARS MARGINAL...OPTED NOT TO RAISE A SMALL CRAFT ADVISORY. IN THE WAKE OF COLD FROPA...WINDS WILL SHIFT TOWARD THE NORTHWEST. TUESDAY THROUGH FRIDAY LOOK FAIRLY QUIET OVER THE WATERS AS HIGH PRESSURE PREVAILS. && .TIDES/COASTAL FLOODING... THERE IS A CHANCE THAT THE HIGH TIDE COULD REACH OR SLIGHTLY EXCEED 7.0 FT MLLW ON CHARLESTON HARBOR THIS EVENING. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ NEAR TERM...BSH SHORT TERM...SPR LONG TERM...JRL AVIATION...BSH/SPR MARINE...BSH/SPR TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
147 PM EDT SUN APR 19 2015 .SYNOPSIS... A WARM FRONT WILL LIFT INTO THE AREA TODAY...ACCOMPANIED BY AN UPPER LEVEL DISTURBANCE. A COLD FRONT WILL APPROACH THE AREA MONDAY... MOVING OFFSHORE MONDAY NIGHT. HIGH PRESSURE WILL BUILD IN TUESDAY THROUGH THURSDAY. A WEAK COLD FRONT WILL DROP THROUGH THE AREA THURSDAY NIGHT...THEN A STORM SYSTEM WILL AFFECT THE REGION NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... EARLY THIS AFTERNOON...QUICK UPDATE TO INCLUDE TORNADO WATCH 79 WHICH IS IN EFFECT THROUGH 8 PM. NO CHANGE TO PREVIOUS FORECAST THINKING AND PREVIOUS DISCUSSION FOLLOWS BELOW. LATE THIS MORNING...THE WARM FRONT PRECIPITATION THAT HAD BLOSSOMED EARLIER THIS MORNING ACROSS SOUTHEAST GEORGIA HAS DISSIPATED PRETTY RAPIDLY AS IT LIFTS TO THE NORTHEAST. AS SUCH...THE REST OF THE MORNING WILL BE RELATIVELY QUIET AHEAD OF THE MAIN FORECAST PROBLEM WHICH IS THE LARGE AREA OF CONVECTION CURRENTLY IMPACTING MUCH OF ALABAMA/GEORGIA/FLORIDA. OVERALL...THERE WILL BE LIMITED PRECIPITATION COVERAGE OUT AHEAD OF THE APPROACHING LINE OTHER THAN SCATTERED DISCRETE SHOWERS/THUNDERSTORMS THAT SHOULD DEVELOP RIGHT AS THE LINE PUSHES INTO THE WESTERN ZONES. CURRENTLY...THE RECENT RUNS OF THE HRRR SEEMS TO HAVE AN EXCELLENT HANDLE ON THE POSITION OF THE CONVECTION AND ITS AFTERNOON PROGRESSION SEEMS QUITE REASONABLE. REGARDING TIMING...THE HRRR IS RUNNING ABOUT AN HOUR OR TWO ON THE SLOW SIDE SO WE THINK THE LINE OF STORMS WILL BEGIN IMPACTING THE WESTERN ZONES IN THE 1-2PM WINDOW. THIS WOULD PUT THE LINE INTO THE SAVANNAH METRO AREA 3-5PM AND THEN THE CHARLESTON REGION BETWEEN 6-8PM. THE POTENTIAL FOR SEVERE WEATHER APPEARS TO BE INCREASING. UPSTREAM OFFICES HAVE BEEN ISSUING A MIXTURE OF SEVERE/TORNADO WARNINGS THIS MORNING WITH A NUMBER OF WIND DAMAGE REPORTS. BASED ON ITS LOCATION RELATIVE TO THE LINE AT 12Z...THE TAE MORNING SOUNDING IS LIKELY THE BEST SAMPLING OF THE APPROACHING NEAR STORM ENVIRONMENT. AS SUCH...WE EXPECT A STRONGLY SHEARED ENVIRONMENT WITH A NICE VEERING OF THE LOW LEVEL PROFILE AND CAPE VALUES INCREASING INTO THE 1500-2000 J/KG RANGE. IN FACT...THE TAE SOUNDING HAS A DISTINCT ELEVATED MIXED LAYER THAT ACTUALLY SHOWS UP WELL WHEN LOOKING AT HRRR SOUNDINGS LATER THIS AFTERNOON. ONE OF THE MORE TROUBLING ASPECTS IS THE POTENTIAL FOR A WINDOW OF CLEARING NOTED ON VISIBLE SATELLITE IMAGERY. AS THIS CLEARING HAS MOVED ACROSS SOUTH GEORGIA TEMPERATURES HAVE RISEN INTO THE UPPER 70S AND EVEN TO 80 WITHIN JUST AN HOUR. GIVEN LOW LEVEL THICKNESS VALUES AS THEY ARE...EVEN A BRIEF PERIOD OF SUN WILL LEAD TO A RAPID WARM UP AND INCREASE THE SURFACE DESTABILIZATION POTENTIAL. SO USING THE HRRR AND ITS SOUNDINGS AS THE BEST REPRESENTATION OF THE AFTERNOON NEAR STORM ENVIRONMENT...IT APPEARS WE ARE LOOKING AT CAPE VALUES AS HIGH AS 2500 J/KG...0-3 KM SHEAR OF 30-35 KT...AND SRH VALUES BETWEEN 150-250 THANKS TO THE SOUTHEAST BACKED LOW LEVEL FLOW. SUCH AN ENVIRONMENT WILL LIKELY FAVOR A CONVECTIVE MODE OF LINEAR SEGMENTS WITH EMBEDDED SUPERCELL ELEMENTS AND EVEN THE POTENTIAL FOR A DISCRETE SUPERCELL OR TWO. DAMAGING WIND GUSTS CONTINUES TO BE THE PRIMARY SEVERE WEATHER THREAT...BUT THE SHEAR AND LOW LEVEL VEERING WILL ALSO PROVIDE A TORNADO THREAT AS WELL. MUCH WILL BE DETERMINED BY HOW MUCH SUN CAN BREAK THROUGH AND TEMPERATURES WARM. ONE OTHER POTENTIAL THING TO WATCH IS THAT THE CURRENT SOUTHEAST WINDS COULD ADVECT IN A SLIGHTLY MORE STABLE MARINE ENVIRONMENT. HOWEVER...GIVEN THAT WE ARE OUT OF THE COOLEST SHELF WATER SEASON THIS IMPACT IS EXPECTED TO BE LIMITED. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... TONIGHT...THE SHORTWAVE WILL PUSH OFF THE COAST AND ELEVATED POPS DURING THE EVENING HOURS SHOULD DECREASE BELOW 15 PERCENT AS SOMEWHAT DRIER AIR AND TEMPORARY SUBSIDENCE DEVELOP OVERNIGHT INTO EARLY MONDAY. ANOTHER IN A SERIES OF VERY MILD OVERNIGHTS WITH TEMPS ONLY FALLING TO THE MID 60S ONCE AGAIN. THE LONGWAVE TROUGH WILL PERSIST TO OUR WEST ON MONDAY WHILE A SERIES OF POTENT SHORTWAVES LIFT NORTHEAST THROUGH THE LOCAL FORECAST AREA. A 145 KT SOUTHERN STREAM JET STREAK IS PROGGED TO SLIDE ALONG THE CENTRAL GULF COAST REGION DURING THE DAY...SPREADING A REGION OF ENHANCED UPPER LEVEL DIVERGENCE INTO SC/GA IN THE AFTERNOON. MODEL TIME SECTIONS SHOW CONSIDERABLE DRYING ABOVE 850 MB EARLY IN THE PERIOD...WITH PWATS DROPPING BELOW 1.25" BY MONDAY AFTERNOON. THE MAIN COLD FRONT WILL SLOWLY MOVE EAST DURING THE DAY...CROSSING THE REGION AT SOME POINT MONDAY EVENING. GIVEN THE DRY AIR ALOFT... CONSIDERABLE BREAKS IN THE CLOUDS AND COMPRESSIONAL HEATING AHEAD OF THE FRONT SHOULD HELP PUSH TEMPS INTO THE MID/UPPER 80S. THE BIG QUESTION ON MONDAY IS HOW MUCH CONVECTIVE COVERAGE DEVELOPS. THE DEEP DRY LAYER ABOVE THE SURFACE MAY LIMIT THE INITIAL CONVECTIVE DEVELOPMENT. HOWEVER...MODELS ARE HINTING AT AN UPSTREAM CONVECTIVE CLUSTER MOVING INTO WESTERN AREAS LATER IN THE AFTERNOON. THERMODYNAMICS AND KINEMATICS ARE QUITE IMPRESSIVE ON MONDAY. 40-50 KT OF 0-6 KM BULK SHEAR...CAPES OF 1500-2000 J/KG AND DOWNDRAFT CAPES 1000 TO 1500 J/KG. A FAIRLY ROBUST SEA BREEZE IS EXPECTED TO DEVELOP IN THE AFTERNOON GIVEN SUCH WARM TEMPS INLAND AND PREVAILING SOUTHERLY FLOW. THIS MAY COME INTO PLAY LATE IN THE DAY IF UPSTREAM CONVECTION MOVES IN FROM THE WEST. GIVEN THE SOMEWHAT DRIER TREND IN THE LATEST MODELS...WE MINIMIZED POPS MONDAY MORNING WITH VALUES INCREASING TO 30-40% IN THE AFTERNOON...ESPECIALLY ACROSS INTERIOR SC/GA. AS THE ACTIVITY AHEAD OF THE FRONT MOVES THROUGH OUR AREA IT SHOULD BE GRADUALLY WEAKENING. THEN SOME ADDITIONAL ACTIVITY...LIKELY WEAKER...COULD ACCOMPANY THE ACTUAL FRONT LATER IN THE EVENING OR OVERNIGHT. WE PLAN TO MAINTAIN SEVERE WEATHER POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT WITH DRY WEATHER AND SEASONABLE TEMPERATURES TUESDAY AND WEDNESDAY. HIGHS WILL CLIMB TO NEAR 80 BOTH DAYS WITH OVERNIGHT LOWS IN THE MID 50S. && .LONG TERM /MONDAY THROUGH SUNDAY/... A ZONAL PATTERN WILL EXIST MUCH OF THE PERIOD. A WEAK BACK DOOR COLD FRONT DROPS THROUGH THE AREA THURSDAY NIGHT. THE FRONT WILL STALL TO THE SOUTH BEFORE LIFTING BACK NORTH AS A WARM FRONT FRIDAY NIGHT AND SATURDAY. A PRONOUNCED SHORTWAVE EMBEDDED IN THE QUASI-ZONAL FLOW WILL MOVE THROUGH SATURDAY NIGHT ACCOMPANIED BY A COLD FRONT. PRECIPITATION POSSIBLE STARTING FRIDAY NIGHT AND CONTINUING INTO SATURDAY NIGHT. TEMPS WILL BE MODERATED BY INCREASING CLOUD COVER AND WEAK COLD ADVECTION. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... MVFR CEILINGS HAVE RETURNED TO BOTH TERMINALS EARLY THIS AFTERNOON AND THE MAIN FORECAST ISSUE THROUGH THE EVENING WILL BE TIMING THUNDERSTORMS INTO THE FORECAST. BASED ON CURRENT RADAR TRENDS AND HI-RES MODEL GUIDANCE...IT LOOKS LIKE THUNDER WILL REACH KSAV AND IMPACT THE TERMINAL BETWEEN 20Z-22Z. HAVE GONE WITH IFR CONDITIONS IN THUNDER WITH GUSTY WINDS TO ALMOST 40 KT BASED ON SOME UPSTREAM OBSERVATIONS. AT KCHS...THUNDER WILL ARRIVE LATER AND IT IS UNCLEAR IF IT WILL BE AS STRONG AS IT IS EXPECTED AT KSAV. HAVE GONE WITH 22Z-00Z AT KCHS WITH IFR CONDITIONS AND SLIGHTLY LESSER WIND GUSTS. ONCE THE CONVECTION MOVE EAST OF THE TERMINALS THERE WILL BE A BIT OF A LULL UNTIL IFR CEILINGS ARE PROGGED TO RETURN AFTER MIDNIGHT. BOTH SITES GET PREVAILING IFR CEILINGS THROUGH THE LATE NIGHT...SCATTERING OUT MONDAY MORNING. EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS/TSTMS EXPECTED AT BOTH TERMINALS MONDAY AFTERNOON AND EVENING WITH BRIEF MVFR CEILING/VSBY RESTRICTIONS POSSIBLE. OTHERWISE VFR CONDITIONS EXPECTED. && .MARINE... A WARM FRONT WILL LIFT THROUGH THE WATERS TODAY...FOLLOWED BY INTENSIFYING SOUTH/SOUTHWEST FLOW. LIGHT AND VARIABLE WINDS EARLY THIS MORNING WILL BECOME SE PRIOR TO THE WARM FRONT WHICH WILL SHIFT FLOW SW TO S TONIGHT. WHILE SPEEDS INCREASE TONIGHT AND SEAS SLOWLY BUILD...THE AVERAGE SPEED COULD REACH ONLY 15 KT BY DAYBREAK OVER NEAR SHORE WATERS WITH SEAS 3 TO 4 FT. THE POTENTIAL EXISTS FOR THUNDERSTORMS WITH STRONG WINDS OVER THE WATERS THIS AFTERNOON EVENING. VERY HEAVY DOWNPOURS REDUCING LOCAL VSBYS BELOW 1 NM ARE ALSO POSSIBLE WITH THE STRONGEST STORMS MOVING OFFSHORE LATE IN THE DAY AND EARLY THIS EVENING. A PREVAILING SSW FLOW WILL EXIST MONDAY MORNING AS A COLD FRONT APPROACHES FROM THE WEST. THE GRADIENT WILL STRENGTHEN DURING THE AFTERNOON...ESPECIALLY ALONG THE COAST WHERE A STRONG SEA BREEZE DEVELOPS DUE TO MID/UPPER 80S TEMPS OVER LAND. THE LATEST GFS AND NAM MOS AT FOLLY BEACH SC SHOW SFC WINDS EXCEEDING 20 KT LATE MONDAY AFTERNOON WHEN THE SEA BREEZE IS STRONGEST. THIS SEEMS FAIRLY REASONABLE GIVEN THE PATTERN AND THE WARMER INLAND TEMPS EXPECTED. A SMALL CRAFT ADVISORY MAY EVENTUALLY BE REQUIRED FOR CHARLESTON HARBOR MONDAY AFTERNOON FOR WINDS/GUSTS IN THE 20-30 KT RANGE. A BRIEF PERIOD OF SMALL CRAFT ADVISORY CONDITIONS MAY DEVELOP OVER OFFSHORE WATERS MONDAY NIGHT AS THE COLD FRONT MOVES THROUGH AND WINDS GUST TO 25 KT WITH SOME 6 FT SEAS ALSO POSSIBLE. TUESDAY THROUGH FRIDAY LOOK FAIRLY QUIET OVER THE WATERS AS HIGH PRESSURE PREVAILS. && .TIDES/COASTAL FLOODING... THERE IS A CHANCE THAT THE HIGH TIDE COULD REACH OR SLIGHTLY EXCEED 7.0 FT MLLW ON CHARLESTON HARBOR THIS EVENING. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ NEAR TERM...BSH SHORT TERM...JRL LONG TERM...JRL AVIATION...BSH MARINE...JRL TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1121 AM EDT SUN APR 19 2015 .SYNOPSIS... A WARM FRONT WILL LIFT INTO THE AREA TODAY...ACCOMPANIED BY AN UPPER LEVEL DISTURBANCE. A COLD FRONT WILL APPROACH THE AREA MONDAY... MOVING OFFSHORE MONDAY NIGHT. HIGH PRESSURE WILL BUILD IN TUESDAY THROUGH THURSDAY. A WEAK COLD FRONT WILL DROP THROUGH THE AREA THURSDAY NIGHT...THEN A STORM SYSTEM WILL AFFECT THE REGION NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATE THIS MORNING...THE WARM FRONT PRECIPITATION THAT HAD BLOSSOMED EARLIER THIS MORNING ACROSS SOUTHEAST GEORGIA HAS DISSIPATED PRETTY RAPIDLY AS IT LIFTS TO THE NORTHEAST. AS SUCH...THE REST OF THE MORNING WILL BE RELATIVELY QUIET AHEAD OF THE MAIN FORECAST PROBLEM WHICH IS THE LARGE AREA OF CONVECTION CURRENTLY IMPACTING MUCH OF ALABAMA/GEORGIA/FLORIDA. OVERALL...THERE WILL BE LIMITED PRECIPITATION COVERAGE OUT AHEAD OF THE APPROACHING LINE OTHER THAN SCATTERED DISCRETE SHOWERS/THUNDERSTORMS THAT SHOULD DEVELOP RIGHT AS THE LINE PUSHES INTO THE WESTERN ZONES. CURRENTLY...THE RECENT RUNS OF THE HRRR SEEMS TO HAVE AN EXCELLENT HANDLE ON THE POSITION OF THE CONVECTION AND ITS AFTERNOON PROGRESSION SEEMS QUITE REASONABLE. REGARDING TIMING...THE HRRR IS RUNNING ABOUT AN HOUR OR TWO ON THE SLOW SIDE SO WE THINK THE LINE OF STORMS WILL BEGIN IMPACTING THE WESTERN ZONES IN THE 1-2PM WINDOW. THIS WOULD PUT THE LINE INTO THE SAVANNAH METRO AREA 3-5PM AND THEN THE CHARLESTON REGION BETWEEN 6-8PM. THE POTENTIAL FOR SEVERE WEATHER APPEARS TO BE INCREASING. UPSTREAM OFFICES HAVE BEEN ISSUING A MIXTURE OF SEVERE/TORNADO WARNINGS THIS MORNING WITH A NUMBER OF WIND DAMAGE REPORTS. BASED ON ITS LOCATION RELATIVE TO THE LINE AT 12Z...THE TAE MORNING SOUNDING IS LIKELY THE BEST SAMPLING OF THE APPROACHING NEAR STORM ENVIRONMENT. AS SUCH...WE EXPECT A STRONGLY SHEARED ENVIRONMENT WITH A NICE VEERING OF THE LOW LEVEL PROFILE AND CAPE VALUES INCREASING INTO THE 1500-2000 J/KG RANGE. IN FACT...THE TAE SOUNDING HAS A DISTINCT ELEVATED MIXED LAYER THAT ACTUALLY SHOWS UP WELL WHEN LOOKING AT HRRR SOUNDINGS LATER THIS AFTERNOON. ONE OF THE MORE TROUBLING ASPECTS IS THE POTENTIAL FOR A WINDOW OF CLEARING NOTED ON VISIBLE SATELLITE IMAGERY. AS THIS CLEARING HAS MOVED ACROSS SOUTH GEORGIA TEMPERATURES HAVE RISEN INTO THE UPPER 70S AND EVEN TO 80 WITHIN JUST AN HOUR. GIVEN LOW LEVEL THICKNESS VALUES AS THEY ARE...EVEN A BRIEF PERIOD OF SUN WILL LEAD TO A RAPID WARM UP AND INCREASE THE SURFACE DESTABILIZATION POTENTIAL. SO USING THE HRRR AND ITS SOUNDINGS AS THE BEST REPRESENTATION OF THE AFTERNOON NEAR STORM ENVIRONMENT...IT APPEARS WE ARE LOOKING AT CAPE VALUES AS HIGH AS 2500 J/KG...0-3 KM SHEAR OF 30-35 KT...AND SRH VALUES BETWEEN 150-250 THANKS TO THE SOUTHEAST BACKED LOW LEVEL FLOW. SUCH AN ENVIRONMENT WILL LIKELY FAVOR A CONVECTIVE MODE OF LINEAR SEGMENTS WITH EMBEDDED SUPERCELL ELEMENTS AND EVEN THE POTENTIAL FOR A DISCRETE SUPERCELL OR TWO. DAMAGING WIND GUSTS CONTINUES TO BE THE PRIMARY SEVERE WEATHER THREAT...BUT THE SHEAR AND LOW LEVEL VEERING WILL ALSO PROVIDE A TORNADO THREAT AS WELL. MUCH WILL BE DETERMINED BY HOW MUCH SUN CAN BREAK THROUGH AND TEMPERATURES WARM. ONE OTHER POTENTIAL THING TO WATCH IS THAT THE CURRENT SOUTHEAST WINDS COULD ADVECT IN A SLIGHTLY MORE STABLE MARINE ENVIRONMENT. HOWEVER...GIVEN THAT WE ARE OUT OF THE COOLEST SHELF WATER SEASON THIS IMPACT IS EXPECTED TO BE LIMITED. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... TONIGHT...THE SHORTWAVE WILL PUSH OFF THE COAST AND ELEVATED POPS DURING THE EVENING HOURS SHOULD DECREASE BELOW 15 PERCENT AS SOMEWHAT DRIER AIR AND TEMPORARY SUBSIDENCE DEVELOP OVERNIGHT INTO EARLY MONDAY. ANOTHER IN A SERIES OF VERY MILD OVERNIGHTS WITH TEMPS ONLY FALLING TO THE MID 60S ONCE AGAIN. THE LONGWAVE TROUGH WILL PERSIST TO OUR WEST ON MONDAY WHILE A SERIES OF POTENT SHORTWAVES LIFT NORTHEAST THROUGH THE LOCAL FORECAST AREA. A 145 KT SOUTHERN STREAM JET STREAK IS PROGGED TO SLIDE ALONG THE CENTRAL GULF COAST REGION DURING THE DAY...SPREADING A REGION OF ENHANCED UPPER LEVEL DIVERGENCE INTO SC/GA IN THE AFTERNOON. MODEL TIME SECTIONS SHOW CONSIDERABLE DRYING ABOVE 850 MB EARLY IN THE PERIOD...WITH PWATS DROPPING BELOW 1.25" BY MONDAY AFTERNOON. THE MAIN COLD FRONT WILL SLOWLY MOVE EAST DURING THE DAY...CROSSING THE REGION AT SOME POINT MONDAY EVENING. GIVEN THE DRY AIR ALOFT... CONSIDERABLE BREAKS IN THE CLOUDS AND COMPRESSIONAL HEATING AHEAD OF THE FRONT SHOULD HELP PUSH TEMPS INTO THE MID/UPPER 80S. THE BIG QUESTION ON MONDAY IS HOW MUCH CONVECTIVE COVERAGE DEVELOPS. THE DEEP DRY LAYER ABOVE THE SURFACE MAY LIMIT THE INITIAL CONVECTIVE DEVELOPMENT. HOWEVER...MODELS ARE HINTING AT AN UPSTREAM CONVECTIVE CLUSTER MOVING INTO WESTERN AREAS LATER IN THE AFTERNOON. THERMODYNAMICS AND KINEMATICS ARE QUITE IMPRESSIVE ON MONDAY. 40-50 KT OF 0-6 KM BULK SHEAR...CAPES OF 1500-2000 J/KG AND DOWNDRAFT CAPES 1000 TO 1500 J/KG. A FAIRLY ROBUST SEA BREEZE IS EXPECTED TO DEVELOP IN THE AFTERNOON GIVEN SUCH WARM TEMPS INLAND AND PREVAILING SOUTHERLY FLOW. THIS MAY COME INTO PLAY LATE IN THE DAY IF UPSTREAM CONVECTION MOVES IN FROM THE WEST. GIVEN THE SOMEWHAT DRIER TREND IN THE LATEST MODELS...WE MINIMIZED POPS MONDAY MORNING WITH VALUES INCREASING TO 30-40% IN THE AFTERNOON...ESPECIALLY ACROSS INTERIOR SC/GA. AS THE ACTIVITY AHEAD OF THE FRONT MOVES THROUGH OUR AREA IT SHOULD BE GRADUALLY WEAKENING. THEN SOME ADDITIONAL ACTIVITY...LIKELY WEAKER...COULD ACCOMPANY THE ACTUAL FRONT LATER IN THE EVENING OR OVERNIGHT. WE PLAN TO MAINTAIN SEVERE WEATHER POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT WITH DRY WEATHER AND SEASONABLE TEMPERATURES TUESDAY AND WEDNESDAY. HIGHS WILL CLIMB TO NEAR 80 BOTH DAYS WITH OVERNIGHT LOWS IN THE MID 50S. && .LONG TERM /MONDAY THROUGH SATURDAY/... A ZONAL PATTERN WILL EXIST MUCH OF THE PERIOD. A WEAK BACK DOOR COLD FRONT DROPS THROUGH THE AREA THURSDAY NIGHT. THE FRONT WILL STALL TO THE SOUTH BEFORE LIFTING BACK NORTH AS A WARM FRONT FRIDAY NIGHT AND SATURDAY. A PRONOUNCED SHORTWAVE EMBEDDED IN THE QUASI-ZONAL FLOW WILL MOVE THROUGH SATURDAY NIGHT ACCOMPANIED BY A COLD FRONT. PRECIPITATION POSSIBLE STARTING FRIDAY NIGHT AND CONTINUING INTO SATURDAY NIGHT. TEMPS WILL BE MODERATED BY INCREASING CLOUD COVER AND WEAK COLD ADVECTION. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... DEEP MOISTURE ACROSS THE TAF CORRIDOR TODAY. LAYERED CLOUDS THIS MORNING DIFFICULT TO PIN DOWN AS RECENTLY LOW STRATUS DECKS DEVELOPED IN THE WARM FRONTAL ZONE DEVELOPING ACROSS THE REGION. MODELS INDICATE THAT IFR/LIFR CIGS AND IFR VSBYS SHOULD BE CONFINED TO THE MORNING HOURS WITH MVFR TO VFR CIGS DEVELOPING IN A BIT OF A DRIER SLOT THIS AFTERNOON AHEAD OF CONVECTION THAT SHOULD SWEEP THROUGH THE TERMINALS IN THE 19Z TO 00Z TIME FRAME. TSTMS ARE POSSIBLE WITH HEAVY DOWNPOURS AND PERHAPS GUSTY AND SHIFTING WINDS. MAINLY VFR TONIGHT BUT MVFR/IFR CIGS ARE POSSIBLE LATE. EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS/TSTMS EXPECTED AT BOTH TERMINALS MONDAY AFTERNOON AND EVENING WITH BRIEF MVFR CEILING/VSBY RESTRICTIONS POSSIBLE. OTHERWISE VFR CONDITIONS EXPECTED. && .MARINE... A WARM FRONT WILL LIFT THROUGH THE WATERS TODAY...FOLLOWED BY INTENSIFYING SOUTH/SOUTHWEST FLOW. LIGHT AND VARIABLE WINDS EARLY THIS MORNING WILL BECOME SE PRIOR TO THE WARM FRONT WHICH WILL SHIFT FLOW SW TO S TONIGHT. WHILE SPEEDS INCREASE TONIGHT AND SEAS SLOWLY BUILD...THE AVERAGE SPEED COULD REACH ONLY 15 KT BY DAYBREAK OVER NEAR SHORE WATERS WITH SEAS 3 TO 4 FT. THE POTENTIAL EXISTS FOR THUNDERSTORMS WITH STRONG WINDS OVER THE WATERS THIS AFTERNOON EVENING. VERY HEAVY DOWNPOURS REDUCING LOCAL VSBYS BELOW 1 NM ARE ALSO POSSIBLE WITH THE STRONGEST STORMS MOVING OFFSHORE LATE IN THE DAY AND EARLY THIS EVENING. A PREVAILING SSW FLOW WILL EXIST MONDAY MORNING AS A COLD FRONT APPROACHES FROM THE WEST. THE GRADIENT WILL STRENGTHEN DURING THE AFTERNOON...ESPECIALLY ALONG THE COAST WHERE A STRONG SEA BREEZE DEVELOPS DUE TO MID/UPPER 80S TEMPS OVER LAND. THE LATEST GFS AND NAM MOS AT FOLLY BEACH SC SHOW SFC WINDS EXCEEDING 20 KT LATE MONDAY AFTERNOON WHEN THE SEA BREEZE IS STRONGEST. THIS SEEMS FAIRLY REASONABLE GIVEN THE PATTERN AND THE WARMER INLAND TEMPS EXPECTED. A SMALL CRAFT ADVISORY MAY EVENTUALLY BE REQUIRED FOR CHARLESTON HARBOR MONDAY AFTERNOON FOR WINDS/GUSTS IN THE 20-30 KT RANGE. A BRIEF PERIOD OF SMALL CRAFT ADVISORY CONDITIONS MAY DEVELOP OVER OFFSHORE WATERS MONDAY NIGHT AS THE COLD FRONT MOVES THROUGH AND WINDS GUST TO 25 KT WITH SOME 6 FT SEAS ALSO POSSIBLE. TUESDAY THROUGH FRIDAY LOOK FAIRLY QUIET OVER THE WATERS AS HIGH PRESSURE PREVAILS. && .TIDES/COASTAL FLOODING... THERE IS A CHANCE THAT THE HIGH TIDE COULD REACH OR SLIGHTLY EXCEED 7.0 FT MLLW ON CHARLESTON HARBOR THIS EVENING. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ NEAR TERM...BSH SHORT TERM...JRL LONG TERM...JRL AVIATION... MARINE...JRL TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
508 PM CDT SUN APR 19 2015 .SHORT TERM... 319 PM CDT THROUGH MONDAY NIGHT... AFTER ANOTHER WARM EARLY AFTERNOON ACROSS MUCH OF THE REGION RAIN IS BEGINNING TO SPREAD NORTHWARD ACROSS SOUTHERN SECTIONS OF THE CHICAGO METRO AREA AS OF THIS WRITING. THIS ACTIVITY WILL CONTINUE TO OVERSPREAD THE REGION THROUGH THE AFTERNOON AND EVENING...WITH TEMPERATURES LIKELY TO DROP BACK INTO THE UPPER 50S AND LOW 60S IN THE RAIN. THE MID-LEVEL DISTURBANCE...AND THE ASSOCIATED SURFACE SYSTEM WILL QUICKLY SHIFT NORTHWARD OVER LOWER MICHIGAN OVERNIGHT...AND IT APPEARS THAT THE RAIN WILL BECOME MORE SHOWERY AND INTERMITTENT OR POSSIBLY JUST SOME DRIZZLE LATER THIS EVENING AND INTO THE EARLY MORNING ACROSS MUCH OF THE AREA AS THIS INITIAL MID LEVEL DISTURBANCE SHIFTS NORTH OF THE AREA AND SOME DRIER MID LEVEL AIR SHIFTS OVER THE SOUTHEASTERN HALF OF MY AREA. SOME ADDITIONAL RAIN SHOWERS ARE POSSIBLE AGAIN EARLY MONDAY WITHIN A REGION OF MID LEVEL DEFORMATION AND RAP AROUND MOISTURE ASSOCIATED WITH THE DEEPENING LOWER AND MID LEVEL LOW OVER THE UPPER GREAT LAKES REGION AND SOUTHERN CANADA. CONDITIONS SHOULD DRY OUT MONDAY AFTERNOON...WITH ONLY A SMALL CHANCE OF AN ADDITIONAL SHOWER DEVELOPING AS COLDER AIR ALOFT STEEPENS THE LOWER LEVEL LAPSE RATES. THE MAIN STORY DURING THE AFTERNOON WILL BE THE WINDS. WINDS ARE EXPECTED TO INCREASE OUT OF THE WEST-NORTHWEST DURING THE DAY AS STOUT SURFACE PRESSURE GRADIENT SETS UP OVER THE REGION AS THE SURFACE LOW DEEPENS TO AROUND 985 MB ACROSS ONTARIO MONDAY AFTERNOON. MODEL SOUNDINGS SUGGEST GOOD AFTERNOON MIXING TO AROUND 850 MB SHOULD ALLOW FOR GUSTS OF AROUND 30 KT AT TIMES...ESPECIALLY DURING THE AFTERNOON. THESE WIND GUSTS SHOULD ABATE MONDAY EVENING...BUT STRONG WINDS LOOK TO DEVELOP AGAIN ON TUESDAY. SEE LONG TERM DISCUSSION FOR MORE INFO ON TUESDAY`S WINDS. KJB && .LONG TERM... 319 PM CDT TUESDAY THROUGH SUNDAY... MAIN FORECAST CONCERNS/CHALLENGES ARE WITH BELOW NORMAL TEMPS THROUGH THE FORECAST. LARGE UPPER LEVEL CENTER WILL BE CENTERED ACROSS THE REGION AT THE START OF THE PERIOD...AND REMAIN SITUATED THROUGH MUCH OF THE WORK WEEK AS IT SLOWLY MOVES EAST. SEVERAL VORT LOBES ARE ANTICIPATED TO WRAP AROUND THIS UPPER LEVEL LOW ON TUESDAY AND WITH STEEPENING LAPSE RATES...EXPECT SKY COVER TO INCREASE THROUGH THE DAY WHILE SCATTERED SHOWERS BECOME POSSIBLE...ESPECIALLY ACROSS NORTHERN ILLINOIS. AS THIS OCCURS...LIKELY DEEP MIXING WITH STRONG FLOW ALOFT WILL ALLOW FOR ANOTHER WINDY DAY. GUIDANCE IS SUGGESTING THAT ADVISORY CONDITIONS COULD BE REACHED IN THE AFTERNOON...AND WILL NEED TO CONTINUE MONITORING THIS POTENTIAL. ANY REMAINING PRECIP AND CLOUD COVER SHOULD EXIT THE AREA TUESDAY NIGHT WITH DRY CONDITIONS EXPECTED. SOME GUIDANCE DEVELOPS A SWATH OF PRECIP OVER THE CWA LATE IN THE NIGHT INTO EARLY WEDNESDAY. HOWEVER...A MORE LIKELY SCENARIO AT THIS TIME WOULD BE FOR DRY CONDITIONS AND SO HAVE LEFT OUT ANY POPS AT THIS TIME. ONGOING CAA WILL MAKE FOR CHILLY CONDITIONS TUESDAY NIGHT...WITH LOW TEMPS IN THE 30S. IF PRECIP WERE TO OCCUR DURING THIS PERIOD...THESE COLDER CONDITIONS COULD SUPPORT THE POTENTIAL FOR AT LEAST A RAIN SNOW MIX ACROSS NORTHERN ILLINOIS. EXPECT DRY CONDITIONS WITH BELOW NORMAL TEMPS THROUGH THE REST OF THE FORECAST PERIOD...WITH FORECAST HIGHS IN THE 50S. COLD NIGHT TIME LOWS IN THE 30S COULD BECOME AN ISSUE LATE IN THE WORK WEEK AS HIGH PRESSURE IS ANTICIPATED TO MOVE OVERHEAD...WITH LIGHTER WINDS AND THE COLD TEMPS POSSIBLY CREATING A SETUP FOR FROST. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * EAST TO NORTHEAST WINDS AROUND 10 KT THROUGH MID EVENING. * LIGHT TO MODERATE RAIN THROUGH MID-EVENING THEN BECOMING MORE SHOWERY. * QUICKLY LOWERING CIGS THROUGH SUNDOWN THEN GRADUALLY LOWERING THROUGH IFR CATEGORY...POSSIBLY EVEN TO LIFR BY 03Z. * GRADUALLY LOWERING VISIBILITY THROUGH THIS EVENING WITH IFR VISIBILITY LIKELY PREVAILING BY MID EVENING. * ANOTHER ROUND OF -SHRA PROBABLE EARLY MONDAY MORNING. * GUSTY WEST WINDS WITH MAX GUSTS ARND 30 KT MONDAY AFTN. MTF/JEE //DISCUSSION...UPDATED 18Z... RAIN IS SLOWLY PUSHING NORTH AND IS JUST SOUTH OF I-80 AT THIS TIME. MVFR AND LOWER CIGS ARE OVER CENTRAL AND SOUTHERN IL AND INDIANA BUT ALSO PUSHING NORTH. ADJUSTED PRECIP AND CIG TIMING BASED ON RADAR AND SATELLITE TRENDS. MVFR VSBY WILL BE TIED TO THE HEAVIER RAIN SHOWERS...AND CIGS WILL LOWER TO MVFR LATE THIS AFTN AND THEN TO IFR THIS EVENING. ALL GUIDANCE MEMBERS SHOW IFR CIGS ACROSS THE TERMINALS. WILL EITHER SEE SCATTERED SHOWERS OR A BREAK IN RAIN AFTER MIDNIGHT TONIGHT WITH ANOTHER ROUND OF RAIN PUSHING WEST TO EAST EARLY MONDAY MORNING. EAST WINDS BCM NORTHEAST ARND 10 KT LATE THIS AFTN AND BACK TO NW BY 03Z. WINDS CONTINUE TO BACK TO WEST BY EARLY MONDAY MORNING. GUSTY WINDS FOLLOW THE BAND OF RAIN SHOWERS...WITH 20G30KT EXPECTED BY MONDAY AFTERNOON. THINKING THE GUSTY WINDS AND DRIER AIR WILL HELP CIGS LIFT LATE MONDAY MORNING AND AFTN...BUT HAVE MEDIUM CONFIDENCE IN HOW QUICKLY CIGS LIFT TO VFR. JEE //ORD AND MDW CONFIDENCE...UPDATED 22Z... * MEDIUM-HIGH IN WINDS. * HIGH IN RAIN TIMING. * MEDIUM-HIGH IN IFR CIG TIMING AND MEDIUM IN VISIBILITY TIMING. * HIGH IN IFR CIG DURATION. LOW-MEDIUM IN IFR VISIBILITY DURATION. MTF/JEE //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR BECOMING VFR. TUESDAY...SLGT CHANCE PM SHRA...BUT MAINLY VFR. GUSTY WEST WINDS. WEDNESDAY...SLGT CHANCE SHRA. MAINLY VFR. WEST-NORTHWEST WINDS. THURSDAY...VFR. NORTH-NORTHEAST WINDS. FRIDAY...MAINLY VFR. CHC PM SHRA. SATURDAY...MAINLY VFR. BEACHLER && .MARINE... 324 PM CDT AS A TROUGH OF LOW PRESSURE AND SECONDARY LOW PRESSURE CENTER MOVE ACROSS THE GREAT LAKES REGION TONIGHT...WINDS WILL LIKELY BE VARIABLE AT TIMES. THIS WILL ESPECIALLY BE THE CASE OVER THE SOUTHERN HALF OF THE LAKE WHERE THE LOW PRESSURE SYSTEM IS EXPECTED TO MOVE THROUGH. IN THE NEAR TERM...EAST NORTHEAST WINDS WILL PREVAIL OVER THE LAKE WITH THE HIGHEST SPEEDS TO 30 KT OCCURRING OVER THE NORTHERN HALF AND WHILE 15 TO 25 KT WINDS ARE BEING OBSERVED OVER THE SOUTH...WITH SPEEDS EXPECTED TO SLIGHTLY DIMINISH TONIGHT. AS THIS TROUGH/LOW EXIT TO THE EAST ON MONDAY...STRONGER WESTERLY WINDS WILL DEVELOP. HIGHEST WINDS TO 30 KT WILL OCCUR ALONG THE NEARSHORE WATERS WHILE ONLY 15 TO 25 KT ARE LIKELY OVER THE OPEN WATERS. A SIMILAR SETUP IS EXPECTED ON TUESDAY BUT WITH SPEEDS SLIGHTLY HIGHER...AS TO 30 KT WILL LIKELY PREVAIL FOR BOTH LOCATIONS AND WITH EVEN GALES POSSIBLE ALONG THE NEARSHORE WATERS DURING THE DAY. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744- LMZ745...11 AM MONDAY TO 9 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
325 PM CDT SUN APR 19 2015 .SHORT TERM... 319 PM CDT THROUGH MONDAY NIGHT... AFTER ANOTHER WARM EARLY AFTERNOON ACROSS MUCH OF THE REGION RAIN IS BEGINNING TO SPREAD NORTHWARD ACROSS SOUTHERN SECTIONS OF THE CHICAGO METRO AREA AS OF THIS WRITING. THIS ACTIVITY WILL CONTINUE TO OVERSPREAD THE REGION THROUGH THE AFTERNOON AND EVENING...WITH TEMPERATURES LIKELY TO DROP BACK INTO THE UPPER 50S AND LOW 60S IN THE RAIN. THE MID-LEVEL DISTURBANCE...AND THE ASSOCIATED SURFACE SYSTEM WILL QUICKLY SHIFT NORTHWARD OVER LOWER MICHIGAN OVERNIGHT...AND IT APPEARS THAT THE RAIN WILL BECOME MORE SHOWERY AND INTERMITTENT OR POSSIBLY JUST SOME DRIZZLE LATER THIS EVENING AND INTO THE EARLY MORNING ACROSS MUCH OF THE AREA AS THIS INITIAL MID LEVEL DISTURBANCE SHIFTS NORTH OF THE AREA AND SOME DRIER MID LEVEL AIR SHIFTS OVER THE SOUTHEASTERN HALF OF MY AREA. SOME ADDITIONAL RAIN SHOWERS ARE POSSIBLE AGAIN EARLY MONDAY WITHIN A REGION OF MID LEVEL DEFORMATION AND RAP AROUND MOISTURE ASSOCIATED WITH THE DEEPENING LOWER AND MID LEVEL LOW OVER THE UPPER GREAT LAKES REGION AND SOUTHERN CANADA. CONDITIONS SHOULD DRY OUT MONDAY AFTERNOON...WITH ONLY A SMALL CHANCE OF AN ADDITIONAL SHOWER DEVELOPING AS COLDER AIR ALOFT STEEPENS THE LOWER LEVEL LAPSE RATES. THE MAIN STORY DURING THE AFTERNOON WILL BE THE WINDS. WINDS ARE EXPECTED TO INCREASE OUT OF THE WEST-NORTHWEST DURING THE DAY AS STOUT SURFACE PRESSURE GRADIENT SETS UP OVER THE REGION AS THE SURFACE LOW DEEPENS TO AROUND 985 MB ACROSS ONTARIO MONDAY AFTERNOON. MODEL SOUNDINGS SUGGEST GOOD AFTERNOON MIXING TO AROUND 850 MB SHOULD ALLOW FOR GUSTS OF AROUND 30 KT AT TIMES...ESPECIALLY DURING THE AFTERNOON. THESE WIND GUSTS SHOULD ABATE MONDAY EVENING...BUT STRONG WINDS LOOK TO DEVELOP AGAIN ON TUESDAY. SEE LONG TERM DISCUSSION FOR MORE INFO ON TUESDAY`S WINDS. KJB && .LONG TERM... 319 PM CDT TUESDAY THROUGH SUNDAY... MAIN FORECAST CONCERNS/CHALLENGES ARE WITH BELOW NORMAL TEMPS THROUGH THE FORECAST. LARGE UPPER LEVEL CENTER WILL BE CENTERED ACROSS THE REGION AT THE START OF THE PERIOD...AND REMAIN SITUATED THROUGH MUCH OF THE WORK WEEK AS IT SLOWLY MOVES EAST. SEVERAL VORT LOBES ARE ANTICIPATED TO WRAP AROUND THIS UPPER LEVEL LOW ON TUESDAY AND WITH STEEPENING LAPSE RATES...EXPECT SKY COVER TO INCREASE THROUGH THE DAY WHILE SCATTERED SHOWERS BECOME POSSIBLE...ESPECIALLY ACROSS NORTHERN ILLINOIS. AS THIS OCCURS...LIKELY DEEP MIXING WITH STRONG FLOW ALOFT WILL ALLOW FOR ANOTHER WINDY DAY. GUIDANCE IS SUGGESTING THAT ADVISORY CONDITIONS COULD BE REACHED IN THE AFTERNOON...AND WILL NEED TO CONTINUE MONITORING THIS POTENTIAL. ANY REMAINING PRECIP AND CLOUD COVER SHOULD EXIT THE AREA TUESDAY NIGHT WITH DRY CONDITIONS EXPECTED. SOME GUIDANCE DEVELOPS A SWATH OF PRECIP OVER THE CWA LATE IN THE NIGHT INTO EARLY WEDNESDAY. HOWEVER...A MORE LIKELY SCENARIO AT THIS TIME WOULD BE FOR DRY CONDITIONS AND SO HAVE LEFT OUT ANY POPS AT THIS TIME. ONGOING CAA WILL MAKE FOR CHILLY CONDITIONS TUESDAY NIGHT...WITH LOW TEMPS IN THE 30S. IF PRECIP WERE TO OCCUR DURING THIS PERIOD...THESE COLDER CONDITIONS COULD SUPPORT THE POTENTIAL FOR AT LEAST A RAIN SNOW MIX ACROSS NORTHERN ILLINOIS. EXPECT DRY CONDITIONS WITH BELOW NORMAL TEMPS THROUGH THE REST OF THE FORECAST PERIOD...WITH FORECAST HIGHS IN THE 50S. COLD NIGHT TIME LOWS IN THE 30S COULD BECOME AN ISSUE LATE IN THE WORK WEEK AS HIGH PRESSURE IS ANTICIPATED TO MOVE OVERHEAD...WITH LIGHTER WINDS AND THE COLD TEMPS POSSIBLY CREATING A SETUP FOR FROST. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * EAST WINDS ARND 10 KT BCMG NORTH LESS THAN 10 KT THIS EVENING. * RAIN MOVING IN OVER THE NEXT 1-2 HOURS WITH MVFR VSBY. COULD HAVE PERIODS OF IFR VSBY WITH HEAVIEST SHOWERS. * CIGS LOWER TO IFR LATE THIS AFTN THROUGH EARLY MONDAY MORNING. * SCATTERED SHOWERS OVERNIGHT WITH ANOTHER ROUND OF -SHRA EARLY MONDAY MORNING. * GUSTY WEST WINDS WITH MAX GUSTS ARND 30 KT MONDAY AFTN. JEE //DISCUSSION...UPDATED 18Z... RAIN IS SLOWLY PUSHING NORTH AND IS JUST SOUTH OF I-80 AT THIS TIME. MVFR AND LOWER CIGS ARE OVER CENTRAL AND SOUTHERN IL AND INDIANA BUT ALSO PUSHING NORTH. ADJUSTED PRECIP AND CIG TIMING BASED ON RADAR AND SATELLITE TRENDS. MVFR VSBY WILL BE TIED TO THE HEAVIER RAIN SHOWERS...AND CIGS WILL LOWER TO MVFR LATE THIS AFTN AND THEN TO IFR THIS EVENING. ALL GUIDANCE MEMBERS SHOW IFR CIGS ACROSS THE TERMINALS. WILL EITHER SEE SCATTERED SHOWERS OR A BREAK IN RAIN AFTER MIDNIGHT TONIGHT WITH ANOTHER ROUND OF RAIN PUSHING WEST TO EAST EARLY MONDAY MORNING. EAST WINDS BCM NORTHEAST ARND 10 KT LATE THIS AFTN AND BACK TO NW BY 03Z. WINDS CONTINUE TO BACK TO WEST BY EARLY MONDAY MORNING. GUSTY WINDS FOLLOW THE BAND OF RAIN SHOWERS...WITH 20G30KT EXPECTED BY MONDAY AFTERNOON. THINKING THE GUSTY WINDS AND DRIER AIR WILL HELP CIGS LIFT LATE MONDAY MORNING AND AFTN...BUT HAVE MEDIUM CONFIDENCE IN HOW QUICKLY CIGS LIFT TO VFR. JEE //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN RAIN SHOWERS THIS AFTERNOON AND EVENING. * HIGH CONFIDENCE IN PERIODS OF MVFR VSBY...LOW CONFIDENCE IN OCCURRENCE AND PERSISTENCE OF IFR VSBY. * HIGH CONFIDENCE IN IFR CIGS...MEDIUM CONFIDENCE TIMING AND PERSISTENCE. * HIGH CONFIDENCE IN WIND TRENDS OVERNIGHT...MEDIUM CONFIDENCE IN TIMING OF BACKING WINDS. * HIGH CONFIDENCE IN ALL OTHER FORECAST PARAMETERS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR BECOMING VFR. TUESDAY...SLGT CHANCE PM SHRA...BUT MAINLY VFR. GUSTY WEST WINDS. WEDNESDAY...SLGT CHANCE SHRA. MAINLY VFR. WEST-NORTHWEST WINDS. THURSDAY...VFR. NORTH-NORTHEAST WINDS. FRIDAY...MAINLY VFR. CHC PM SHRA. SATURDAY...MAINLY VFR. BEACHLER && .MARINE... 324 PM CDT AS A TROUGH OF LOW PRESSURE AND SECONDARY LOW PRESSURE CENTER MOVE ACROSS THE GREAT LAKES REGION TONIGHT...WINDS WILL LIKELY BE VARIABLE AT TIMES. THIS WILL ESPECIALLY BE THE CASE OVER THE SOUTHERN HALF OF THE LAKE WHERE THE LOW PRESSURE SYSTEM IS EXPECTED TO MOVE THROUGH. IN THE NEAR TERM...EAST NORTHEAST WINDS WILL PREVAIL OVER THE LAKE WITH THE HIGHEST SPEEDS TO 30 KT OCCURRING OVER THE NORTHERN HALF AND WHILE 15 TO 25 KT WINDS ARE BEING OBSERVED OVER THE SOUTH...WITH SPEEDS EXPECTED TO SLIGHTLY DIMINISH TONIGHT. AS THIS TROUGH/LOW EXIT TO THE EAST ON MONDAY...STRONGER WESTERLY WINDS WILL DEVELOP. HIGHEST WINDS TO 30 KT WILL OCCUR ALONG THE NEARSHORE WATERS WHILE ONLY 15 TO 25 KT ARE LIKELY OVER THE OPEN WATERS. A SIMILAR SETUP IS EXPECTED ON TUESDAY BUT WITH SPEEDS SLIGHTLY HIGHER...AS TO 30 KT WILL LIKELY PREVAIL FOR BOTH LOCATIONS AND WITH EVEN GALES POSSIBLE ALONG THE NEARSHORE WATERS DURING THE DAY. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
320 PM CDT SUN APR 19 2015 .SHORT TERM... 319 PM CDT THROUGH MONDAY NIGHT... AFTER ANOTHER WARM EARLY AFTERNOON ACROSS MUCH OF THE REGION RAIN IS BEGINNING TO SPREAD NORTHWARD ACROSS SOUTHERN SECTIONS OF THE CHICAGO METRO AREA AS OF THIS WRITING. THIS ACTIVITY WILL CONTINUE TO OVERSPREAD THE REGION THROUGH THE AFTERNOON AND EVENING...WITH TEMPERATURES LIKELY TO DROP BACK INTO THE UPPER 50S AND LOW 60S IN THE RAIN. THE MID-LEVEL DISTURBANCE...AND THE ASSOCIATED SURFACE SYSTEM WILL QUICKLY SHIFT NORTHWARD OVER LOWER MICHIGAN OVERNIGHT...AND IT APPEARS THAT THE RAIN WILL BECOME MORE SHOWERY AND INTERMITTENT OR POSSIBLY JUST SOME DRIZZLE LATER THIS EVENING AND INTO THE EARLY MORNING ACROSS MUCH OF THE AREA AS THIS INITIAL MID LEVEL DISTURBANCE SHIFTS NORTH OF THE AREA AND SOME DRIER MID LEVEL AIR SHIFTS OVER THE SOUTHEASTERN HALF OF MY AREA. SOME ADDITIONAL RAIN SHOWERS ARE POSSIBLE AGAIN EARLY MONDAY WITHIN A REGION OF MID LEVEL DEFORMATION AND RAP AROUND MOISTURE ASSOCIATED WITH THE DEEPENING LOWER AND MID LEVEL LOW OVER THE UPPER GREAT LAKES REGION AND SOUTHERN CANADA. CONDITIONS SHOULD DRY OUT MONDAY AFTERNOON...WITH ONLY A SMALL CHANCE OF AN ADDITIONAL SHOWER DEVELOPING AS COLDER AIR ALOFT STEEPENS THE LOWER LEVEL LAPSE RATES. THE MAIN STORY DURING THE AFTERNOON WILL BE THE WINDS. WINDS ARE EXPECTED TO INCREASE OUT OF THE WEST-NORTHWEST DURING THE DAY AS STOUT SURFACE PRESSURE GRADIENT SETS UP OVER THE REGION AS THE SURFACE LOW DEEPENS TO AROUND 985 MB ACROSS ONTARIO MONDAY AFTERNOON. MODEL SOUNDINGS SUGGEST GOOD AFTERNOON MIXING TO AROUND 850 MB SHOULD ALLOW FOR GUSTS OF AROUND 30 KT AT TIMES...ESPECIALLY DURING THE AFTERNOON. THESE WIND GUSTS SHOULD ABATE MONDAY EVENING...BUT STRONG WINDS LOOK TO DEVELOP AGAIN ON TUESDAY. SEE LONG TERM DISCUSSION FOR MORE INFO ON TUESDAY`S WINDS. KJB && .LONG TERM... 319 PM CDT TUESDAY THROUGH SUNDAY... MAIN FORECAST CONCERNS/CHALLENGES ARE WITH BELOW NORMAL TEMPS THROUGH THE FORECAST. LARGE UPPER LEVEL CENTER WILL BE CENTERED ACROSS THE REGION AT THE START OF THE PERIOD...AND REMAIN SITUATED THROUGH MUCH OF THE WORK WEEK AS IT SLOWLY MOVES EAST. SEVERAL VORT LOBES ARE ANTICIPATED TO WRAP AROUND THIS UPPER LEVEL LOW ON TUESDAY AND WITH STEEPENING LAPSE RATES...EXPECT SKY COVER TO INCREASE THROUGH THE DAY WHILE SCATTERED SHOWERS BECOME POSSIBLE...ESPECIALLY ACROSS NORTHERN ILLINOIS. AS THIS OCCURS...LIKELY DEEP MIXING WITH STRONG FLOW ALOFT WILL ALLOW FOR ANOTHER WINDY DAY. GUIDANCE IS SUGGESTING THAT ADVISORY CONDITIONS COULD BE REACHED IN THE AFTERNOON...AND WILL NEED TO CONTINUE MONITORING THIS POTENTIAL. ANY REMAINING PRECIP AND CLOUD COVER SHOULD EXIT THE AREA TUESDAY NIGHT WITH DRY CONDITIONS EXPECTED. SOME GUIDANCE DEVELOPS A SWATH OF PRECIP OVER THE CWA LATE IN THE NIGHT INTO EARLY WEDNESDAY. HOWEVER...A MORE LIKELY SCENARIO AT THIS TIME WOULD BE FOR DRY CONDITIONS AND SO HAVE LEFT OUT ANY POPS AT THIS TIME. ONGOING CAA WILL MAKE FOR CHILLY CONDITIONS TUESDAY NIGHT...WITH LOW TEMPS IN THE 30S. IF PRECIP WERE TO OCCUR DURING THIS PERIOD...THESE COLDER CONDITIONS COULD SUPPORT THE POTENTIAL FOR AT LEAST A RAIN SNOW MIX ACROSS NORTHERN ILLINOIS. EXPECT DRY CONDITIONS WITH BELOW NORMAL TEMPS THROUGH THE REST OF THE FORECAST PERIOD...WITH FORECAST HIGHS IN THE 50S. COLD NIGHT TIME LOWS IN THE 30S COULD BECOME AN ISSUE LATE IN THE WORK WEEK AS HIGH PRESSURE IS ANTICIPATED TO MOVE OVERHEAD...WITH LIGHTER WINDS AND THE COLD TEMPS POSSIBLY CREATING A SETUP FOR FROST. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * EAST WINDS ARND 10 KT BCMG NORTH LESS THAN 10 KT THIS EVENING. * RAIN MOVING IN OVER THE NEXT 1-2 HOURS WITH MVFR VSBY. COULD HAVE PERIODS OF IFR VSBY WITH HEAVIEST SHOWERS. * CIGS LOWER TO IFR LATE THIS AFTN THROUGH EARLY MONDAY MORNING. * SCATTERED SHOWERS OVERNIGHT WITH ANOTHER ROUND OF -SHRA EARLY MONDAY MORNING. * GUSTY WEST WINDS WITH MAX GUSTS ARND 30 KT MONDAY AFTN. JEE //DISCUSSION...UPDATED 18Z... RAIN IS SLOWLY PUSHING NORTH AND IS JUST SOUTH OF I-80 AT THIS TIME. MVFR AND LOWER CIGS ARE OVER CENTRAL AND SOUTHERN IL AND INDIANA BUT ALSO PUSHING NORTH. ADJUSTED PRECIP AND CIG TIMING BASED ON RADAR AND SATELLITE TRENDS. MVFR VSBY WILL BE TIED TO THE HEAVIER RAIN SHOWERS...AND CIGS WILL LOWER TO MVFR LATE THIS AFTN AND THEN TO IFR THIS EVENING. ALL GUIDANCE MEMBERS SHOW IFR CIGS ACROSS THE TERMINALS. WILL EITHER SEE SCATTERED SHOWERS OR A BREAK IN RAIN AFTER MIDNIGHT TONIGHT WITH ANOTHER ROUND OF RAIN PUSHING WEST TO EAST EARLY MONDAY MORNING. EAST WINDS BCM NORTHEAST ARND 10 KT LATE THIS AFTN AND BACK TO NW BY 03Z. WINDS CONTINUE TO BACK TO WEST BY EARLY MONDAY MORNING. GUSTY WINDS FOLLOW THE BAND OF RAIN SHOWERS...WITH 20G30KT EXPECTED BY MONDAY AFTERNOON. THINKING THE GUSTY WINDS AND DRIER AIR WILL HELP CIGS LIFT LATE MONDAY MORNING AND AFTN...BUT HAVE MEDIUM CONFIDENCE IN HOW QUICKLY CIGS LIFT TO VFR. JEE //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN RAIN SHOWERS THIS AFTERNOON AND EVENING. * HIGH CONFIDENCE IN PERIODS OF MVFR VSBY...LOW CONFIDENCE IN OCCURRENCE AND PERSISTENCE OF IFR VSBY. * HIGH CONFIDENCE IN IFR CIGS...MEDIUM CONFIDENCE TIMING AND PERSISTENCE. * HIGH CONFIDENCE IN WIND TRENDS OVERNIGHT...MEDIUM CONFIDENCE IN TIMING OF BACKING WINDS. * HIGH CONFIDENCE IN ALL OTHER FORECAST PARAMETERS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR BECOMING VFR. TUESDAY...SLGT CHANCE PM SHRA...BUT MAINLY VFR. GUSTY WEST WINDS. WEDNESDAY...SLGT CHANCE SHRA. MAINLY VFR. WEST-NORTHWEST WINDS. THURSDAY...VFR. NORTH-NORTHEAST WINDS. FRIDAY...MAINLY VFR. CHC PM SHRA. SATURDAY...MAINLY VFR. BEACHLER && .MARINE... 257 AM CDT LOW PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY LIFT NORTHEAST TOWARDS THE LOWER GREAT LAKES REGION TONIGHT/EARLY MON. GUIDANCE CONTINUES TO INDICATE THE GRADIENT WILL TIGHTEN ACROSS THE LAKE...HOWEVER THIS APPEARS TO BE MORE FOCUSED ALONG THE SOUTHERN TIP OF THE LAKE. WITH THE CONTINUED EASTERLY WINDS...IT IS POSSIBLE MARGINAL SMALL CRAFT CONDITIONS MAY DEVELOP FOR THE ILLINOIS SHORELINE LATER TODAY INTO TONIGHT. THE LOW PRESSURE WILL THEN APPROACH THE LAKE AND BRIEFLY WEAKEN THE GRADIENT EARLY MON. THEN AS THE LOW LIFTS NORTHEAST LATER IN THE DAY MON...IT WILL DEEPEN AND MERGE WITH ANOTHER LOW...WHICH WILL CREATE A TIGHT GRADIENT OVER THE LAKE AND INCREASING WEST/NORTHWEST TUE. AFTER TUE THE DOMINANT WIND DIRECTION WILL BE NORTHWEST THROUGH MID- WEEK...BEFORE RELAXING TO THE WEST. THIS WILL ALLOW HIGHER WAVES TO BE FOCUSED IN THE SOUTHERN HALF OF LAKE MICHIGAN THROUGH MID- WEEK. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
248 PM CDT SUN APR 19 2015 .UPDATE... 952 AM CDT I MADE SOME UPDATES TO THE FORECAST FOR TODAY TO RAISE TEMPERATURES AND PUSH OFF THE TIMING OF THE RAIN CHANCES. WATER VAPOR IMAGERY INDICATES OUR MID/UPPER LEVEL DISTURBANCE OF INTEREST FOR LATER TODAY NOW LIFTING NORTHWARD ACROSS WESTERN KENTUCKY. THIS FEATURE IS CURRENTLY SUPPORTING AN AREA OF NORTHWARD MOVING SHOWERS ACROSS SOUTHERN PORTIONS OF ILLINOIS AND INDIANA. THEREFORE...THIS AREA OF SHOWERS WILL GRADUALLY WORK NORTHWARD ACROSS NORTHEASTERN ILLINOIS AND NORTHWESTERN INDIANA DURING THE AFTERNOON. IT APPEARS THE THREAT FOR THUNDERSTORMS WILL BE VERY LOW WITH THIS ACTIVITY...WITH TRENDS SUGGESTING NO LIGHTNING STRIKES OVER THE PAST FEW HOURS...SO I HAVE REMOVED THE MENTION OF SUCH THIS AFTERNOON. IN ADDITION...WITH THE SLOWER ONSET OF PRECIP TODAY...IT APPEARS TEMPERATURES WILL BE ABLE TO WARM TO NEAR 70 IN MOST AREAS AWAY FROM LAKE MICHIGAN...SO I RAISED HIGH TEMPERATURES TODAY. KJB && .SHORT TERM... 340 AM CDT THROUGH MONDAY... UPPER AIR ANALYSIS EARLY THIS MORNING DEPICTS DEEP UPPER LEVEL LOW PRESSURE NOW PUSHING INTO WESTERN KANSAS. MULTIPLE VORT MAXES ARE ROTATING AROUND THE LOW. THE STRONGEST OF THESE EXIST IN TEXAS AND THROUGH THE CENTRAL PLAINS...WITH SOME SMALLER SCALE WAVES EXTENDING INTO EASTERN MO/FAR WESTERN IL WERE SOME SCATTERED THUNDERSTORMS WERE ONGOING. A NORTHERN STREAM SHORTWAVE IS ENTERING THE NORTHERN PLAINS WITH SOME SHOWERS OUT AHEAD OF IT AS WELL. AT THE SURFACE...THE COLD FRONT THAT PASSED THROUGH NORTHEAST ILLINOIS AND NW INDIANA SATURDAY HAS PUSHED INTO CENTRAL ILLINOIS...BUT HAS LIKELY COMPLETED ITS SOUTHWARD RETREAT AND HAS WASHED OUT OVER THE PAST FEW HOURS. OVER THE LOCAL AREA...MUCH DRIER NE FLOW EXISTS WITH DEWPOINTS IN THE MID TO UPPER 20S IN THE CITY TO NEAR 40 SOUTH...THOUGH DEWPOINTS ARE POOLING ALONG THE FRONT IN THE UPPER 40S JUST SOUTH OF THE LOT CWA. THE SURFACE LOW THAT IS EXPECTED TO DEVELOP FROM THE SOUTHERN STREAM SHORTWAVE IS ALSO TAKING SHAPE OVER THE SOUTHERN STATES WITH A WARM FRONTAL BOUNDARY EXTENDING FROM WESTERN ARKANSAS THROUGH THE LOWER TENNESSEE VALLEY. AN EXPANSION OF LOWER CLOUD TOPS ON IR IMAGERY ALONG AND AHEAD OF THE WARM FRONT IS OCCURRING. LOW LEVEL WARM/MOIST ADVECTION WILL CONTINUE ITS SLOW PROGRESSION NORTHWARD UNDER MODEST SOUTH/SOUTHEAST FLOW. DEEPER MOISTURE/LIFT REALLY HOLD OFF UNTIL THE AFTERNOON PERIOD ACROSS MOST OF THE AREA. A SOMEWHAT COMPLICATED EVOLUTION AS A MAIN SURFACE LOW CENTER IS FORECAST TO STRENGTHEN AS IT LIFTS NORTH THROUGH INDIANA TODAY THEN FURTHER STRENGTHEN TONIGHT INTO MONDAY WHILE SEVERAL ADDITIONAL SURFACE LOWS DEVELOP AND EVENTUALLY MERGE WITH THE MAIN LOW CENTER. THE SURFACE LOW WILL EVENTUALLY BECOME DRIVEN BY A COMBINATION OF THE SW FLOW AHEAD OF THE SOUTHERN STREAM UPPER LOW AND THE NORTHERN STREAM SHORTWAVE. OF NOTE LATER TODAY...EXPECT COVERAGE OF SHOWERS TO INITIALLY BE SLOW GIVEN THE DRIER AIR PLACE...BUT INCREASING ASCENT ALOFT...LOW LEVEL SSE ISENTROPIC ASCENT AHEAD OF THE LOW AND WRAPPING AROUND THE CLOSED CIRCULATION EXTENDING THROUGH 850 AND EVEN 700 MB COMBINED WITH MODEST LOWER LEVEL FGEN SHOULD ALLOW FOR A BLOSSOMING OF SHOWERS ACROSS THE AREA LATER THIS AFTERNOON AND EVENING. THE HIGHEST PWAT AXIS EXPANDS ACROSS INDIANA TODAY BUT SHOULD GET WRAPPED INTO NE ILLINOIS. RAP MOST UNSTABLE CAPE VALUES RELATIVELY LOW BUT DO EXPAND FROM SE TO NW THIS AFTERNOON AND THIS COUPLED WITH THE PUNCH FROM THE DRY SLOT OF THIS SYSTEM MAY ENABLE A FEW T-STORMS AS WELL...SO SOME OF THE SHOWERS WILL HAVE A MODEST KICK TO THEM IN THE MODERATE/HEAVY RAINFALL DEPARTMENT. EXPECT THAT NORTH CENTRAL ILLINOIS MAY BE UNDER A BIT OF SQUEEZE PLAY FROM THESE TWO SYSTEMS...THUS WHILE SHOWERS ARE STILL EXPECTED...HIGHER CONFIDENCE EXISTS IN COVERAGE FARTHER EAST. THIS EVENING THE FIRST MAIN SHORTWAVE WILL BE PASSING NE WHILE THE MAIN SOUTHERN STREAM ENERGY PASSES EAST THROUGH THE OHIO VALLEY...AND THE NORTHERN STREAM SHORTWAVE LAGS BEHIND BACK IN MN/IA. THERE IS ALSO THE LOSS OF DEEPER MOISTURE...THEREFORE EXPECT SHOWERS TO TAPER/END/TURN TO DRIZZLE POSSIBLY OVERNIGHT FOR A TIME. THEN MONDAY MORNING WE GET THE COUPLED UPPER LEVEL FORCING FROM THE NORTHERN STREAM LOW AND SURFACE COLD FRONT WHICH WILL LIKELY BRING ANOTHER ROUND OF SHOWERS MONDAY MORNING. SHOWERS WILL EASE MONDAY AFTERNOON. IT WILL BE QUITE BREEZY/WINDY BEHIND THE FRONT ON MONDAY IN THE COLD ADVECTION REGIME. KMD && .LONG TERM... 340 AM CDT MONDAY NIGHT THROUGH SATURDAY... THE THEME OF THE EXTENDED WILL BE THE UNSEASONABLY COOL WEATHER. A HIGH AMPLITUDE PATTERN WILL BE IN PLACE WITH STRONG UPPER LEVEL RIDGING EXTENDING WELL NORTH INTO THE CANADIAN ROCKIES AND SIMILARLY HIGH AMPLITUDE RIDGING IN THE NORTH ATLANTIC. THAT LEAVES OUR NORTHERN STREAM SHORTWAVE FROM SUNDAY/MONDAY WITH NO WHERE TO GO. THIS WILL KEEP MUCH OF THE EASTERN HALF OF THE COUNTY...INCLUDING OUR REGION...UNDER COOL NORTHWEST FLOW. THIS PATTERN ALSO FAVORED STRONGLY SHEARED OUT AND ELONGATED VORT MAXES TO PIVOT THROUGH BRINGING PERIODS OF SHOWERS. WITH PWAT VALUES QUITE LOW IN THIS AIRMASS...MUCH OF THE PERIOD WILL BE DRY AND EVEN THE SHOWERS SHOULD NOT BE VERY STRONG. BUT MORE IMPORTANTLY...SEASONAL AVERAGE HIGHS/LOWS FOR LATE APRIL ARE THE LOWER 60S (MID 60S SOUTH) AND LOWER 40S RESPECTIVELY...AND MUCH OF THIS PERIOD WILL FEATURE HIGHS IN THE 50S AND LOWS IN THE MID 30S...POSSIBLY COOLER A NIGHT OR TWO IF WINDS ARE LIGHTER. TEMPERATURE ANOMALIES ARE NOT THAT EXTREME THOUGH...SO RECORD COLD IS NOT ANTICIPATED. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * EAST WINDS ARND 10 KT BCMG NORTH LESS THAN 10 KT THIS EVENING. * RAIN MOVING IN OVER THE NEXT 1-2 HOURS WITH MVFR VSBY. COULD HAVE PERIODS OF IFR VSBY WITH HEAVIEST SHOWERS. * CIGS LOWER TO IFR LATE THIS AFTN THROUGH EARLY MONDAY MORNING. * SCATTERED SHOWERS OVERNIGHT WITH ANOTHER ROUND OF -SHRA EARLY MONDAY MORNING. * GUSTY WEST WINDS WITH MAX GUSTS ARND 30 KT MONDAY AFTN. JEE //DISCUSSION...UPDATED 18Z... RAIN IS SLOWLY PUSHING NORTH AND IS JUST SOUTH OF I-80 AT THIS TIME. MVFR AND LOWER CIGS ARE OVER CENTRAL AND SOUTHERN IL AND INDIANA BUT ALSO PUSHING NORTH. ADJUSTED PRECIP AND CIG TIMING BASED ON RADAR AND SATELLITE TRENDS. MVFR VSBY WILL BE TIED TO THE HEAVIER RAIN SHOWERS...AND CIGS WILL LOWER TO MVFR LATE THIS AFTN AND THEN TO IFR THIS EVENING. ALL GUIDANCE MEMBERS SHOW IFR CIGS ACROSS THE TERMINALS. WILL EITHER SEE SCATTERED SHOWERS OR A BREAK IN RAIN AFTER MIDNIGHT TONIGHT WITH ANOTHER ROUND OF RAIN PUSHING WEST TO EAST EARLY MONDAY MORNING. EAST WINDS BCM NORTHEAST ARND 10 KT LATE THIS AFTN AND BACK TO NW BY 03Z. WINDS CONTINUE TO BACK TO WEST BY EARLY MONDAY MORNING. GUSTY WINDS FOLLOW THE BAND OF RAIN SHOWERS...WITH 20G30KT EXPECTED BY MONDAY AFTERNOON. THINKING THE GUSTY WINDS AND DRIER AIR WILL HELP CIGS LIFT LATE MONDAY MORNING AND AFTN...BUT HAVE MEDIUM CONFIDENCE IN HOW QUICKLY CIGS LIFT TO VFR. JEE //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN RAIN SHOWERS THIS AFTERNOON AND EVENING. * HIGH CONFIDENCE IN PERIODS OF MVFR VSBY...LOW CONFIDENCE IN OCCURRENCE AND PERSISTENCE OF IFR VSBY. * HIGH CONFIDENCE IN IFR CIGS...MEDIUM CONFIDENCE TIMING AND PERSISTENCE. * HIGH CONFIDENCE IN WIND TRENDS OVERNIGHT...MEDIUM CONFIDENCE IN TIMING OF BACKING WINDS. * HIGH CONFIDENCE IN ALL OTHER FORECAST PARAMETERS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR BECOMING VFR. TUESDAY...SLGT CHANCE PM SHRA...BUT MAINLY VFR. GUSTY WEST WINDS. WEDNESDAY...SLGT CHANCE SHRA. MAINLY VFR. WEST-NORTHWEST WINDS. THURSDAY...VFR. NORTH-NORTHEAST WINDS. FRIDAY...MAINLY VFR. CHC PM SHRA. SATURDAY...MAINLY VFR. BEACHLER && .MARINE... 257 AM CDT LOW PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY LIFT NORTHEAST TOWARDS THE LOWER GREAT LAKES REGION TONIGHT/EARLY MON. GUIDANCE CONTINUES TO INDICATE THE GRADIENT WILL TIGHTEN ACROSS THE LAKE...HOWEVER THIS APPEARS TO BE MORE FOCUSED ALONG THE SOUTHERN TIP OF THE LAKE. WITH THE CONTINUED EASTERLY WINDS...IT IS POSSIBLE MARGINAL SMALL CRAFT CONDITIONS MAY DEVELOP FOR THE ILLINOIS SHORELINE LATER TODAY INTO TONIGHT. THE LOW PRESSURE WILL THEN APPROACH THE LAKE AND BRIEFLY WEAKEN THE GRADIENT EARLY MON. THEN AS THE LOW LIFTS NORTHEAST LATER IN THE DAY MON...IT WILL DEEPEN AND MERGE WITH ANOTHER LOW...WHICH WILL CREATE A TIGHT GRADIENT OVER THE LAKE AND INCREASING WEST/NORTHWEST TUE. AFTER TUE THE DOMINANT WIND DIRECTION WILL BE NORTHWEST THROUGH MID- WEEK...BEFORE RELAXING TO THE WEST. THIS WILL ALLOW HIGHER WAVES TO BE FOCUSED IN THE SOUTHERN HALF OF LAKE MICHIGAN THROUGH MID- WEEK. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1237 PM CDT SUN APR 19 2015 .UPDATE... 952 AM CDT I MADE SOME UPDATES TO THE FORECAST FOR TODAY TO RAISE TEMPERATURES AND PUSH OFF THE TIMING OF THE RAIN CHANCES. WATER VAPOR IMAGERY INDICATES OUR MID/UPPER LEVEL DISTURBANCE OF INTEREST FOR LATER TODAY NOW LIFTING NORTHWARD ACROSS WESTERN KENTUCKY. THIS FEATURE IS CURRENTLY SUPPORTING AN AREA OF NORTHWARD MOVING SHOWERS ACROSS SOUTHERN PORTIONS OF ILLINOIS AND INDIANA. THEREFORE...THIS AREA OF SHOWERS WILL GRADUALLY WORK NORTHWARD ACROSS NORTHEASTERN ILLINOIS AND NORTHWESTERN INDIANA DURING THE AFTERNOON. IT APPEARS THE THREAT FOR THUNDERSTORMS WILL BE VERY LOW WITH THIS ACTIVITY...WITH TRENDS SUGGESTING NO LIGHTNING STRIKES OVER THE PAST FEW HOURS...SO I HAVE REMOVED THE MENTION OF SUCH THIS AFTERNOON. IN ADDITION...WITH THE SLOWER ONSET OF PRECIP TODAY...IT APPEARS TEMPERATURES WILL BE ABLE TO WARM TO NEAR 70 IN MOST AREAS AWAY FROM LAKE MICHIGAN...SO I RAISED HIGH TEMPERATURES TODAY. KJB && .SHORT TERM... 340 AM CDT THROUGH MONDAY... UPPER AIR ANALYSIS EARLY THIS MORNING DEPICTS DEEP UPPER LEVEL LOW PRESSURE NOW PUSHING INTO WESTERN KANSAS. MULTIPLE VORT MAXES ARE ROTATING AROUND THE LOW. THE STRONGEST OF THESE EXIST IN TEXAS AND THROUGH THE CENTRAL PLAINS...WITH SOME SMALLER SCALE WAVES EXTENDING INTO EASTERN MO/FAR WESTERN IL WERE SOME SCATTERED THUNDERSTORMS WERE ONGOING. A NORTHERN STREAM SHORTWAVE IS ENTERING THE NORTHERN PLAINS WITH SOME SHOWERS OUT AHEAD OF IT AS WELL. AT THE SURFACE...THE COLD FRONT THAT PASSED THROUGH NORTHEAST ILLINOIS AND NW INDIANA SATURDAY HAS PUSHED INTO CENTRAL ILLINOIS...BUT HAS LIKELY COMPLETED ITS SOUTHWARD RETREAT AND HAS WASHED OUT OVER THE PAST FEW HOURS. OVER THE LOCAL AREA...MUCH DRIER NE FLOW EXISTS WITH DEWPOINTS IN THE MID TO UPPER 20S IN THE CITY TO NEAR 40 SOUTH...THOUGH DEWPOINTS ARE POOLING ALONG THE FRONT IN THE UPPER 40S JUST SOUTH OF THE LOT CWA. THE SURFACE LOW THAT IS EXPECTED TO DEVELOP FROM THE SOUTHERN STREAM SHORTWAVE IS ALSO TAKING SHAPE OVER THE SOUTHERN STATES WITH A WARM FRONTAL BOUNDARY EXTENDING FROM WESTERN ARKANSAS THROUGH THE LOWER TENNESSEE VALLEY. AN EXPANSION OF LOWER CLOUD TOPS ON IR IMAGERY ALONG AND AHEAD OF THE WARM FRONT IS OCCURRING. LOW LEVEL WARM/MOIST ADVECTION WILL CONTINUE ITS SLOW PROGRESSION NORTHWARD UNDER MODEST SOUTH/SOUTHEAST FLOW. DEEPER MOISTURE/LIFT REALLY HOLD OFF UNTIL THE AFTERNOON PERIOD ACROSS MOST OF THE AREA. A SOMEWHAT COMPLICATED EVOLUTION AS A MAIN SURFACE LOW CENTER IS FORECAST TO STRENGTHEN AS IT LIFTS NORTH THROUGH INDIANA TODAY THEN FURTHER STRENGTHEN TONIGHT INTO MONDAY WHILE SEVERAL ADDITIONAL SURFACE LOWS DEVELOP AND EVENTUALLY MERGE WITH THE MAIN LOW CENTER. THE SURFACE LOW WILL EVENTUALLY BECOME DRIVEN BY A COMBINATION OF THE SW FLOW AHEAD OF THE SOUTHERN STREAM UPPER LOW AND THE NORTHERN STREAM SHORTWAVE. OF NOTE LATER TODAY...EXPECT COVERAGE OF SHOWERS TO INITIALLY BE SLOW GIVEN THE DRIER AIR PLACE...BUT INCREASING ASCENT ALOFT...LOW LEVEL SSE ISENTROPIC ASCENT AHEAD OF THE LOW AND WRAPPING AROUND THE CLOSED CIRCULATION EXTENDING THROUGH 850 AND EVEN 700 MB COMBINED WITH MODEST LOWER LEVEL FGEN SHOULD ALLOW FOR A BLOSSOMING OF SHOWERS ACROSS THE AREA LATER THIS AFTERNOON AND EVENING. THE HIGHEST PWAT AXIS EXPANDS ACROSS INDIANA TODAY BUT SHOULD GET WRAPPED INTO NE ILLINOIS. RAP MOST UNSTABLE CAPE VALUES RELATIVELY LOW BUT DO EXPAND FROM SE TO NW THIS AFTERNOON AND THIS COUPLED WITH THE PUNCH FROM THE DRY SLOT OF THIS SYSTEM MAY ENABLE A FEW T-STORMS AS WELL...SO SOME OF THE SHOWERS WILL HAVE A MODEST KICK TO THEM IN THE MODERATE/HEAVY RAINFALL DEPARTMENT. EXPECT THAT NORTH CENTRAL ILLINOIS MAY BE UNDER A BIT OF SQUEEZE PLAY FROM THESE TWO SYSTEMS...THUS WHILE SHOWERS ARE STILL EXPECTED...HIGHER CONFIDENCE EXISTS IN COVERAGE FARTHER EAST. THIS EVENING THE FIRST MAIN SHORTWAVE WILL BE PASSING NE WHILE THE MAIN SOUTHERN STREAM ENERGY PASSES EAST THROUGH THE OHIO VALLEY...AND THE NORTHERN STREAM SHORTWAVE LAGS BEHIND BACK IN MN/IA. THERE IS ALSO THE LOSS OF DEEPER MOISTURE...THEREFORE EXPECT SHOWERS TO TAPER/END/TURN TO DRIZZLE POSSIBLY OVERNIGHT FOR A TIME. THEN MONDAY MORNING WE GET THE COUPLED UPPER LEVEL FORCING FROM THE NORTHERN STREAM LOW AND SURFACE COLD FRONT WHICH WILL LIKELY BRING ANOTHER ROUND OF SHOWERS MONDAY MORNING. SHOWERS WILL EASE MONDAY AFTERNOON. IT WILL BE QUITE BREEZY/WINDY BEHIND THE FRONT ON MONDAY IN THE COLD ADVECTION REGIME. KMD && .LONG TERM... 340 AM CDT MONDAY NIGHT THROUGH SATURDAY... THE THEME OF THE EXTENDED WILL BE THE UNSEASONABLY COOL WEATHER. A HIGH AMPLITUDE PATTERN WILL BE IN PLACE WITH STRONG UPPER LEVEL RIDGING EXTENDING WELL NORTH INTO THE CANADIAN ROCKIES AND SIMILARLY HIGH AMPLITUDE RIDGING IN THE NORTH ATLANTIC. THAT LEAVES OUR NORTHERN STREAM SHORTWAVE FROM SUNDAY/MONDAY WITH NO WHERE TO GO. THIS WILL KEEP MUCH OF THE EASTERN HALF OF THE COUNTY...INCLUDING OUR REGION...UNDER COOL NORTHWEST FLOW. THIS PATTERN ALSO FAVORED STRONGLY SHEARED OUT AND ELONGATED VORT MAXES TO PIVOT THROUGH BRINGING PERIODS OF SHOWERS. WITH PWAT VALUES QUITE LOW IN THIS AIRMASS...MUCH OF THE PERIOD WILL BE DRY AND EVEN THE SHOWERS SHOULD NOT BE VERY STRONG. BUT MORE IMPORTANTLY...SEASONAL AVERAGE HIGHS/LOWS FOR LATE APRIL ARE THE LOWER 60S (MID 60S SOUTH) AND LOWER 40S RESPECTIVELY...AND MUCH OF THIS PERIOD WILL FEATURE HIGHS IN THE 50S AND LOWS IN THE MID 30S...POSSIBLY COOLER A NIGHT OR TWO IF WINDS ARE LIGHTER. TEMPERATURE ANOMALIES ARE NOT THAT EXTREME THOUGH...SO RECORD COLD IS NOT ANTICIPATED. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * EAST WINDS 10-14 KT BCMG NORTH LESS THAN 10 KT THIS EVENING. * RAIN ARRIVES 21-22Z WITH 5SM VSBY WITH HEAVIER SHOWERS. * CIGS LOWER TO MVFR LATE THIS AFTN THEN TO IFR THIS EVENING THROUGH EARLY MONDAY MORNING. * SCATTERED SHOWERS OVERNIGHT WITH ANOTHER ROUND OF -SHRA EARLY MONDAY MORNING. * GUSTY WEST WINDS WITH MAX GUSTS ARND 30 KT MONDAY AFTN. JEE //DISCUSSION...UPDATED 18Z... RAIN IS SLOWLY PUSHING NORTH AND IS JUST SOUTH OF I-80 AT THIS TIME. MVFR AND LOWER CIGS ARE OVER CENTRAL AND SOUTHERN IL AND INDIANA BUT ALSO PUSHING NORTH. ADJUSTED PRECIP AND CIG TIMING BASED ON RADAR AND SATELLITE TRENDS. MVFR VSBY WILL BE TIED TO THE HEAVIER RAIN SHOWERS...AND CIGS WILL LOWER TO MVFR LATE THIS AFTN AND THEN TO IFR THIS EVENING. ALL GUIDANCE MEMBERS SHOW IFR CIGS ACROSS THE TERMINALS. WILL EITHER SEE SCATTERED SHOWERS OR A BREAK IN RAIN AFTER MIDNIGHT TONIGHT WITH ANOTHER ROUND OF RAIN PUSHING WEST TO EAST EARLY MONDAY MORNING. EAST WINDS BCM NORTHEAST ARND 10 KT LATE THIS AFTN AND BACK TO NW BY 03Z. WINDS CONTINUE TO BACK TO WEST BY EARLY MONDAY MORNING. GUSTY WINDS FOLLOW THE BAND OF RAIN SHOWERS...WITH 20G30KT EXPECTED BY MONDAY AFTERNOON. THINKING THE GUSTY WINDS AND DRIER AIR WILL HELP CIGS LIFT LATE MONDAY MORNING AND AFTN...BUT HAVE MEDIUM CONFIDENCE IN HOW QUICKLY CIGS LIFT TO VFR. JEE //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN RAIN SHOWERS THIS AFTERNOON AND EVENING. * HIGH CONFIDENCE IN MVFR CIGS...MEDIUM CONFIDENCE IN MVFR CIG TIMING AND OCCURRENCE AND TIMING OF IFR CIGS. * HIGH CONFIDENCE IN WIND TRENDS OVERNIGHT...MEDIUM CONFIDENCE IN TIMING OF BACKING WINDS. * MEDIUM CONFIDENCE IN HOW QUICKLY CIGS LIFT TO VFR MONDAY. * HIGH CONFIDENCE IN ALL OTHER FORECAST PARAMETERS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR BECOMING VFR. TUESDAY...SLGT CHANCE PM SHRA...BUT MAINLY VFR. GUSTY WEST WINDS. WEDNESDAY...SLGT CHANCE SHRA. MAINLY VFR. WEST-NORTHWEST WINDS. THURSDAY...VFR. NORTH-NORTHEAST WINDS. FRIDAY...MAINLY VFR. CHC PM SHRA. SATURDAY...MAINLY VFR. BEACHLER && .MARINE... 257 AM CDT LOW PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY LIFT NORTHEAST TOWARDS THE LOWER GREAT LAKES REGION TONIGHT/EARLY MON. GUIDANCE CONTINUES TO INDICATE THE GRADIENT WILL TIGHTEN ACROSS THE LAKE...HOWEVER THIS APPEARS TO BE MORE FOCUSED ALONG THE SOUTHERN TIP OF THE LAKE. WITH THE CONTINUED EASTERLY WINDS...IT IS POSSIBLE MARGINAL SMALL CRAFT CONDITIONS MAY DEVELOP FOR THE ILLINOIS SHORELINE LATER TODAY INTO TONIGHT. THE LOW PRESSURE WILL THEN APPROACH THE LAKE AND BRIEFLY WEAKEN THE GRADIENT EARLY MON. THEN AS THE LOW LIFTS NORTHEAST LATER IN THE DAY MON...IT WILL DEEPEN AND MERGE WITH ANOTHER LOW...WHICH WILL CREATE A TIGHT GRADIENT OVER THE LAKE AND INCREASING WEST/NORTHWEST TUE. AFTER TUE THE DOMINANT WIND DIRECTION WILL BE NORTHWEST THROUGH MID- WEEK...BEFORE RELAXING TO THE WEST. THIS WILL ALLOW HIGHER WAVES TO BE FOCUSED IN THE SOUTHERN HALF OF LAKE MICHIGAN THROUGH MID- WEEK. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1229 PM CDT SUN APR 19 2015 .UPDATE... ISSUED AT 1114 AM CDT SUN APR 19 2015 SFC LOW LIFTING NORTHWARD INTO THE REGION AND PUSHING PLENTY OF WAA RAIN AHEAD OF IT ACROSS THE FA. PLENTY OF PRECIP EXPECTED TODAY AND INTO TONIGHT, BUT MORE SCATTERED IN NATURE IN THE OVERNIGHT HOURS. SOME DRY AIR WORKING AROUND THE LOW AND ERODING SOME OF THE RAINFALL MAY BRING A BREAK IN THE RAINFALL BRIEFLY...BUT NOT ENOUGH TO PULL PRECIP ANYWHERE FOR LONG. HAVE MADE A FEW ADJUSTMENTS TO THE FORECAST, BUT NO MAJOR UPDATES ARE ANTICIPATED AT THIS TIME. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 328 AM CDT SUN APR 19 2015 LATEST WATER VAPOR IMAGERY CONTINUES TO SHOW CLOSED UPPER LOW OVER EASTERN COLORADO, WITH LEAD SHORT-WAVE ROTATING AROUND THIS FEATURE ACROSS ARKANSAS/LOUISIANA. AS THIS WAVE LIFTS NORTHWARD, PRECIP WILL EVENTUALLY SPREAD INTO CENTRAL ILLINOIS TODAY. 07Z/2AM RADAR MOSAIC SHOWS DRY CONDITIONS ACROSS THE ENTIRE KILX CWA: HOWEVER, SHOWERS ARE BEGINNING TO DEVELOP AND BECOME MORE WIDESPREAD FURTHER SOUTH ACROSS WESTERN KENTUCKY AND FAR SOUTHERN ILLINOIS. BASED ON RADAR TIMING TOOLS AND LATEST HRRR FORECAST, THINK SCATTERED SHOWERS WILL ARRIVE SOUTH OF I-70 OVER THE NEXT COUPLE OF HOURS, THEN WILL SPREAD NORTHWARD TOWARD THE I-74 CORRIDOR BY MIDDAY. HAVE ADJUSTED POPS TO ACCOUNT FOR THE SLOWER ARRIVAL OF PRECIP DURING THE MORNING, THEN HAVE GONE WITH CATEGORICAL POPS ACROSS THE BOARD THIS AFTERNOON. ASIDE FROM SOME SBCAPES OF AROUND 1000J/KG ACROSS THE FAR SE CWA, FORECAST SOUNDINGS REMAIN FAIRLY STABLE TODAY. AS A RESULT, AM EXPECTING MAINLY SHOWERS WITH JUST A FEW EMBEDDED THUNDERSTORMS. DUE TO CLOUD COVER AND PRECIP, HIGH TEMPERATURES WILL BE SEVERAL DEGREES COOLER THAN IN RECENT DAYS, WITH READINGS MAINLY IN THE 60S. WARMEST TEMPS OF AROUND 70 WILL BE FOCUSED ALONG/WEST OF THE ILLINOIS RIVER WHERE PRECIP WILL BE SLOWEST TO ARRIVE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 328 AM CDT SUN APR 19 2015 LEAD SHORT-WAVE WILL LIFT INTO NORTHERN ILLINOIS/INDIANA BY EARLY EVENING, LIKELY LEADING TO A TEMPORARY LULL IN THE SHOWERS. MEANWHILE, THE MAIN UPPER LOW WILL GET A SOLID PUSH EASTWARD AND WILL ARRIVE ACROSS ILLINOIS LATER TONIGHT INTO MONDAY MORNING. SHOWERS AND PERHAPS A THUNDERSTORM WILL ACCOMPANY THIS FEATURE, SO WILL CONTINUE LIKELY POPS TONIGHT THROUGH MONDAY MORNING. ONCE THE 500MB VORT MAX AND THE ASSOCIATED SURFACE COLD FRONT PASS TO THE EAST, RAIN CHANCES WILL COME TO AN END BY MONDAY AFTERNOON. THANKS TO A TIGHT PRESSURE GRADIENT BEHIND THE DEPARTING FRONT, STRONG W/NW WINDS GUSTING TO BETWEEN 25 AND 30 MPH WILL DEVELOP ON MONDAY. THE WINDS WILL SUBSIDE FOR A TIME MONDAY NIGHT, BUT WILL ONCE AGAIN INCREASE MARKEDLY DURING THE DAY TUESDAY. HIGH TEMPERATURES BOTH DAYS WILL REMAIN IN THE LOWER 60S, WHILE OVERNIGHT LOWS DIP INTO THE UPPER 30S AND LOWER 40S. 00Z APR 19 MODELS HAVE COME INTO MUCH BETTER AGREEMENT CONCERNING THE EXTENDED FORECAST, WITH CONSENSUS FEATURING A CHILLY AND LARGELY DRY WEEK AHEAD. BOTH THE GFS AND ECMWF INDICATE A WEAK COLD FRONT WILL PASS THROUGH CENTRAL ILLINOIS TUESDAY NIGHT INTO WEDNESDAY: HOWEVER, THEY DISAGREE ON HOW MUCH PRECIP IT WILL GENERATE. THE GFS IS SLIGHTLY WETTER AND FASTER WITH FROPA, WHILE THE ECMWF IS DRIER AND ABOUT 6 HOURS SLOWER WITH THE FRONT. DUE TO THE STRONG NORTHWESTERLY UPPER FLOW PATTERN IN PLACE ACROSS THE MIDWEST, THINK THE FASTER GFS IS THE WAY TO GO WITH TIMING, BUT THINK THE DRIER ECMWF IS BETTER WITH QPF AS DEEP MOISTURE WILL BE LACKING WITH THIS FEATURE. AS A RESULT, HAVE OPTED TO CARRY LOW CHANCE POPS EVERYWHERE TUESDAY NIGHT, THEN ONLY ACROSS THE SE CWA ON WEDNESDAY. ONCE THE FRONT PASSES, A COOL/CANADIAN AIRMASS WILL SETTLE INTO THE REGION FOR THE MIDDLE AND END OF THE WEEK. HIGH TEMPERATURES WILL STRUGGLE TO REACH THE 60 DEGREE MARK ON BOTH WEDNESDAY AND THURSDAY, WHILE LOWS DROP INTO THE 30S. COLDEST MORNING MAY END UP BEING FRIDAY MORNING, WHEN RIDGE OF HIGH PRESSURE IS OVERHEAD AND WINDS WILL BE LIGHTEST. WILL NEED TO KEEP AN EYE ON TEMPS, AS FROST ADVISORIES WILL BE POSSIBLE ACROSS PARTS OF CENTRAL/SOUTHEAST ILLINOIS LATER THIS WEEK. AFTER THAT, ANOTHER SYSTEM WILL APPROACH FROM THE SOUTHWEST BY THE END OF THE WEEK: HOWEVER, ITS INFLUENCE LIKELY WILL NOT BE FELT UNTIL FRIDAY NIGHT/SATURDAY AT THE EARLIEST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1226 PM CDT SUN APR 19 2015 MODELS BRINGING THE SFC LOW UP AND THROUGH THE AREA WITHIN THE TAF PD. TWO MAJOR CONCERNS...VIS DROP AND LOW CIGS ASSOCIATED WITH THE PROLONGED RAIN. HAVE KEPT THE LOWER VIS/CIGS ON THE EASTERN TERMINALS. CONCERN ON THE WEST SIDE IS THE MODEL HINT AT A SECONDARY LINE OF PRECIP SHOWING UP WITH THE 500MB TROF LATER AS THE LOW PULLS OUT TO THE EAST. GUIDANCE NOT REALLY REFLECTING THAT WELL...AND WILL BE IN CONFLICT WITH SOME OF THE DRIER AIR BEING PULLED INTO THE WEST SIDE OF THE SYSTEM. CONFIDENCE LOWER FOR PIA AND SPI THAN THE OTHER SITES. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HJS SHORT TERM...BARNES LONG TERM...BARNES AVIATION...HJS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1119 AM CDT SUN APR 19 2015 .UPDATE... ISSUED AT 1114 AM CDT SUN APR 19 2015 SFC LOW LIFTING NORTHWARD INTO THE REGION AND PUSHING PLENTY OF WAA RAIN AHEAD OF IT ACROSS THE FA. PLENTY OF PRECIP EXPECTED TODAY AND INTO TONIGHT, BUT MORE SCATTERED IN NATURE IN THE OVERNIGHT HOURS. SOME DRY AIR WORKING AROUND THE LOW AND ERODING SOME OF THE RAINFALL MAY BRING A BREAK IN THE RAINFALL BRIEFLY...BUT NOT ENOUGH TO PULL PRECIP ANYWHERE FOR LONG. HAVE MADE A FEW ADJUSTMENTS TO THE FORECAST, BUT NO MAJOR UPDATES ARE ANTICIPATED AT THIS TIME. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 328 AM CDT SUN APR 19 2015 LATEST WATER VAPOR IMAGERY CONTINUES TO SHOW CLOSED UPPER LOW OVER EASTERN COLORADO, WITH LEAD SHORT-WAVE ROTATING AROUND THIS FEATURE ACROSS ARKANSAS/LOUISIANA. AS THIS WAVE LIFTS NORTHWARD, PRECIP WILL EVENTUALLY SPREAD INTO CENTRAL ILLINOIS TODAY. 07Z/2AM RADAR MOSAIC SHOWS DRY CONDITIONS ACROSS THE ENTIRE KILX CWA: HOWEVER, SHOWERS ARE BEGINNING TO DEVELOP AND BECOME MORE WIDESPREAD FURTHER SOUTH ACROSS WESTERN KENTUCKY AND FAR SOUTHERN ILLINOIS. BASED ON RADAR TIMING TOOLS AND LATEST HRRR FORECAST, THINK SCATTERED SHOWERS WILL ARRIVE SOUTH OF I-70 OVER THE NEXT COUPLE OF HOURS, THEN WILL SPREAD NORTHWARD TOWARD THE I-74 CORRIDOR BY MIDDAY. HAVE ADJUSTED POPS TO ACCOUNT FOR THE SLOWER ARRIVAL OF PRECIP DURING THE MORNING, THEN HAVE GONE WITH CATEGORICAL POPS ACROSS THE BOARD THIS AFTERNOON. ASIDE FROM SOME SBCAPES OF AROUND 1000J/KG ACROSS THE FAR SE CWA, FORECAST SOUNDINGS REMAIN FAIRLY STABLE TODAY. AS A RESULT, AM EXPECTING MAINLY SHOWERS WITH JUST A FEW EMBEDDED THUNDERSTORMS. DUE TO CLOUD COVER AND PRECIP, HIGH TEMPERATURES WILL BE SEVERAL DEGREES COOLER THAN IN RECENT DAYS, WITH READINGS MAINLY IN THE 60S. WARMEST TEMPS OF AROUND 70 WILL BE FOCUSED ALONG/WEST OF THE ILLINOIS RIVER WHERE PRECIP WILL BE SLOWEST TO ARRIVE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 328 AM CDT SUN APR 19 2015 LEAD SHORT-WAVE WILL LIFT INTO NORTHERN ILLINOIS/INDIANA BY EARLY EVENING, LIKELY LEADING TO A TEMPORARY LULL IN THE SHOWERS. MEANWHILE, THE MAIN UPPER LOW WILL GET A SOLID PUSH EASTWARD AND WILL ARRIVE ACROSS ILLINOIS LATER TONIGHT INTO MONDAY MORNING. SHOWERS AND PERHAPS A THUNDERSTORM WILL ACCOMPANY THIS FEATURE, SO WILL CONTINUE LIKELY POPS TONIGHT THROUGH MONDAY MORNING. ONCE THE 500MB VORT MAX AND THE ASSOCIATED SURFACE COLD FRONT PASS TO THE EAST, RAIN CHANCES WILL COME TO AN END BY MONDAY AFTERNOON. THANKS TO A TIGHT PRESSURE GRADIENT BEHIND THE DEPARTING FRONT, STRONG W/NW WINDS GUSTING TO BETWEEN 25 AND 30 MPH WILL DEVELOP ON MONDAY. THE WINDS WILL SUBSIDE FOR A TIME MONDAY NIGHT, BUT WILL ONCE AGAIN INCREASE MARKEDLY DURING THE DAY TUESDAY. HIGH TEMPERATURES BOTH DAYS WILL REMAIN IN THE LOWER 60S, WHILE OVERNIGHT LOWS DIP INTO THE UPPER 30S AND LOWER 40S. 00Z APR 19 MODELS HAVE COME INTO MUCH BETTER AGREEMENT CONCERNING THE EXTENDED FORECAST, WITH CONSENSUS FEATURING A CHILLY AND LARGELY DRY WEEK AHEAD. BOTH THE GFS AND ECMWF INDICATE A WEAK COLD FRONT WILL PASS THROUGH CENTRAL ILLINOIS TUESDAY NIGHT INTO WEDNESDAY: HOWEVER, THEY DISAGREE ON HOW MUCH PRECIP IT WILL GENERATE. THE GFS IS SLIGHTLY WETTER AND FASTER WITH FROPA, WHILE THE ECMWF IS DRIER AND ABOUT 6 HOURS SLOWER WITH THE FRONT. DUE TO THE STRONG NORTHWESTERLY UPPER FLOW PATTERN IN PLACE ACROSS THE MIDWEST, THINK THE FASTER GFS IS THE WAY TO GO WITH TIMING, BUT THINK THE DRIER ECMWF IS BETTER WITH QPF AS DEEP MOISTURE WILL BE LACKING WITH THIS FEATURE. AS A RESULT, HAVE OPTED TO CARRY LOW CHANCE POPS EVERYWHERE TUESDAY NIGHT, THEN ONLY ACROSS THE SE CWA ON WEDNESDAY. ONCE THE FRONT PASSES, A COOL/CANADIAN AIRMASS WILL SETTLE INTO THE REGION FOR THE MIDDLE AND END OF THE WEEK. HIGH TEMPERATURES WILL STRUGGLE TO REACH THE 60 DEGREE MARK ON BOTH WEDNESDAY AND THURSDAY, WHILE LOWS DROP INTO THE 30S. COLDEST MORNING MAY END UP BEING FRIDAY MORNING, WHEN RIDGE OF HIGH PRESSURE IS OVERHEAD AND WINDS WILL BE LIGHTEST. WILL NEED TO KEEP AN EYE ON TEMPS, AS FROST ADVISORIES WILL BE POSSIBLE ACROSS PARTS OF CENTRAL/SOUTHEAST ILLINOIS LATER THIS WEEK. AFTER THAT, ANOTHER SYSTEM WILL APPROACH FROM THE SOUTHWEST BY THE END OF THE WEEK: HOWEVER, ITS INFLUENCE LIKELY WILL NOT BE FELT UNTIL FRIDAY NIGHT/SATURDAY AT THE EARLIEST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 542 AM CDT SUN APR 19 2015 MID AND HIGH CLOUDS WILL CONTINUE OVER THE AREA THIS MORNING, EFFECTING ALL TAF SITES UNTIL THE PCPN MOVES INTO THE SITES. WILL START ALL SITES WITH VCSH AS THE PCPN MOVES NORTHWARD AND INITIALLY SATURATES THE LOWER LEVELS, DURING THE MORNING HOURS. THEN BETWEEN 10AM AND NOON, PCPN WILL BECOME MORE DOMINATE AND STEADY. TIMING OF ONSET OF PCPN WAS TAKEN FROM A BLEND OF THE BUFKIT DATA, NAM12, HRRR, AND RADAR TRENDS. MVFR CIGS AND VIS WILL ARRIVE WITH THE RAIN AND CONTINUE THROUGH REST OF TAF VALID PERIOD. PCPN COULD LET UP SOME LATE THIS EVENING, SO HAVE ADDED ANOTHER LINE FOR VCSH AFTER THE BULK OF THE RAIN MOVES THROUGH, AND BEFORE THE NEXT BATCH ARRIVES LATE TONIGHT/EARLY TOMORROW MORNING. WINDS WILL BE EASTERLY TO START, BUT THEN BECOME SOUTHEASTERLY AS THE SYSTEM GET CLOSER TO THE SITES. WITH THE SURFACE LOW PRESSURE AREA MOVING RIGHT OVER THE TAFS, WINDS WILL BE VARIABLE, ENDING AT WEST TO SOUTHWEST LATER TONIGHT. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HJS SHORT TERM...BARNES LONG TERM...BARNES AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1110 AM CDT SUN APR 19 2015 .UPDATE... 952 AM CDT I MADE SOME UPDATES TO THE FORECAST FOR TODAY TO RAISE TEMPERATURES AND PUSH OFF THE TIMING OF THE RAIN CHANCES. WATER VAPOR IMAGERY INDICATES OUR MID/UPPER LEVEL DISTURBANCE OF INTEREST FOR LATER TODAY NOW LIFTING NORTHWARD ACROSS WESTERN KENTUCKY. THIS FEATURE IS CURRENTLY SUPPORTING AN AREA OF NORTHWARD MOVING SHOWERS ACROSS SOUTHERN PORTIONS OF ILLINOIS AND INDIANA. THEREFORE...THIS AREA OF SHOWERS WILL GRADUALLY WORK NORTHWARD ACROSS NORTHEASTERN ILLINOIS AND NORTHWESTERN INDIANA DURING THE AFTERNOON. IT APPEARS THE THREAT FOR THUNDERSTORMS WILL BE VERY LOW WITH THIS ACTIVITY...WITH TRENDS SUGGESTING NO LIGHTNING STRIKES OVER THE PAST FEW HOURS...SO I HAVE REMOVED THE MENTION OF SUCH THIS AFTERNOON. IN ADDITION...WITH THE SLOWER ONSET OF PRECIP TODAY...IT APPEARS TEMPERATURES WILL BE ABLE TO WARM TO NEAR 70 IN MOST AREAS AWAY FROM LAKE MICHIGAN...SO I RAISED HIGH TEMPERATURES TODAY. KJB && .SHORT TERM... 340 AM CDT THROUGH MONDAY... UPPER AIR ANALYSIS EARLY THIS MORNING DEPICTS DEEP UPPER LEVEL LOW PRESSURE NOW PUSHING INTO WESTERN KANSAS. MULTIPLE VORT MAXES ARE ROTATING AROUND THE LOW. THE STRONGEST OF THESE EXIST IN TEXAS AND THROUGH THE CENTRAL PLAINS...WITH SOME SMALLER SCALE WAVES EXTENDING INTO EASTERN MO/FAR WESTERN IL WERE SOME SCATTERED THUNDERSTORMS WERE ONGOING. A NORTHERN STREAM SHORTWAVE IS ENTERING THE NORTHERN PLAINS WITH SOME SHOWERS OUT AHEAD OF IT AS WELL. AT THE SURFACE...THE COLD FRONT THAT PASSED THROUGH NORTHEAST ILLINOIS AND NW INDIANA SATURDAY HAS PUSHED INTO CENTRAL ILLINOIS...BUT HAS LIKELY COMPLETED ITS SOUTHWARD RETREAT AND HAS WASHED OUT OVER THE PAST FEW HOURS. OVER THE LOCAL AREA...MUCH DRIER NE FLOW EXISTS WITH DEWPOINTS IN THE MID TO UPPER 20S IN THE CITY TO NEAR 40 SOUTH...THOUGH DEWPOINTS ARE POOLING ALONG THE FRONT IN THE UPPER 40S JUST SOUTH OF THE LOT CWA. THE SURFACE LOW THAT IS EXPECTED TO DEVELOP FROM THE SOUTHERN STREAM SHORTWAVE IS ALSO TAKING SHAPE OVER THE SOUTHERN STATES WITH A WARM FRONTAL BOUNDARY EXTENDING FROM WESTERN ARKANSAS THROUGH THE LOWER TENNESSEE VALLEY. AN EXPANSION OF LOWER CLOUD TOPS ON IR IMAGERY ALONG AND AHEAD OF THE WARM FRONT IS OCCURRING. LOW LEVEL WARM/MOIST ADVECTION WILL CONTINUE ITS SLOW PROGRESSION NORTHWARD UNDER MODEST SOUTH/SOUTHEAST FLOW. DEEPER MOISTURE/LIFT REALLY HOLD OFF UNTIL THE AFTERNOON PERIOD ACROSS MOST OF THE AREA. A SOMEWHAT COMPLICATED EVOLUTION AS A MAIN SURFACE LOW CENTER IS FORECAST TO STRENGTHEN AS IT LIFTS NORTH THROUGH INDIANA TODAY THEN FURTHER STRENGTHEN TONIGHT INTO MONDAY WHILE SEVERAL ADDITIONAL SURFACE LOWS DEVELOP AND EVENTUALLY MERGE WITH THE MAIN LOW CENTER. THE SURFACE LOW WILL EVENTUALLY BECOME DRIVEN BY A COMBINATION OF THE SW FLOW AHEAD OF THE SOUTHERN STREAM UPPER LOW AND THE NORTHERN STREAM SHORTWAVE. OF NOTE LATER TODAY...EXPECT COVERAGE OF SHOWERS TO INITIALLY BE SLOW GIVEN THE DRIER AIR PLACE...BUT INCREASING ASCENT ALOFT...LOW LEVEL SSE ISENTROPIC ASCENT AHEAD OF THE LOW AND WRAPPING AROUND THE CLOSED CIRCULATION EXTENDING THROUGH 850 AND EVEN 700 MB COMBINED WITH MODEST LOWER LEVEL FGEN SHOULD ALLOW FOR A BLOSSOMING OF SHOWERS ACROSS THE AREA LATER THIS AFTERNOON AND EVENING. THE HIGHEST PWAT AXIS EXPANDS ACROSS INDIANA TODAY BUT SHOULD GET WRAPPED INTO NE ILLINOIS. RAP MOST UNSTABLE CAPE VALUES RELATIVELY LOW BUT DO EXPAND FROM SE TO NW THIS AFTERNOON AND THIS COUPLED WITH THE PUNCH FROM THE DRY SLOT OF THIS SYSTEM MAY ENABLE A FEW T-STORMS AS WELL...SO SOME OF THE SHOWERS WILL HAVE A MODEST KICK TO THEM IN THE MODERATE/HEAVY RAINFALL DEPARTMENT. EXPECT THAT NORTH CENTRAL ILLINOIS MAY BE UNDER A BIT OF SQUEEZE PLAY FROM THESE TWO SYSTEMS...THUS WHILE SHOWERS ARE STILL EXPECTED...HIGHER CONFIDENCE EXISTS IN COVERAGE FARTHER EAST. THIS EVENING THE FIRST MAIN SHORTWAVE WILL BE PASSING NE WHILE THE MAIN SOUTHERN STREAM ENERGY PASSES EAST THROUGH THE OHIO VALLEY...AND THE NORTHERN STREAM SHORTWAVE LAGS BEHIND BACK IN MN/IA. THERE IS ALSO THE LOSS OF DEEPER MOISTURE...THEREFORE EXPECT SHOWERS TO TAPER/END/TURN TO DRIZZLE POSSIBLY OVERNIGHT FOR A TIME. THEN MONDAY MORNING WE GET THE COUPLED UPPER LEVEL FORCING FROM THE NORTHERN STREAM LOW AND SURFACE COLD FRONT WHICH WILL LIKELY BRING ANOTHER ROUND OF SHOWERS MONDAY MORNING. SHOWERS WILL EASE MONDAY AFTERNOON. IT WILL BE QUITE BREEZY/WINDY BEHIND THE FRONT ON MONDAY IN THE COLD ADVECTION REGIME. KMD && .LONG TERM... 340 AM CDT MONDAY NIGHT THROUGH SATURDAY... THE THEME OF THE EXTENDED WILL BE THE UNSEASONABLY COOL WEATHER. A HIGH AMPLITUDE PATTERN WILL BE IN PLACE WITH STRONG UPPER LEVEL RIDGING EXTENDING WELL NORTH INTO THE CANADIAN ROCKIES AND SIMILARLY HIGH AMPLITUDE RIDGING IN THE NORTH ATLANTIC. THAT LEAVES OUR NORTHERN STREAM SHORTWAVE FROM SUNDAY/MONDAY WITH NO WHERE TO GO. THIS WILL KEEP MUCH OF THE EASTERN HALF OF THE COUNTY...INCLUDING OUR REGION...UNDER COOL NORTHWEST FLOW. THIS PATTERN ALSO FAVORED STRONGLY SHEARED OUT AND ELONGATED VORT MAXES TO PIVOT THROUGH BRINGING PERIODS OF SHOWERS. WITH PWAT VALUES QUITE LOW IN THIS AIRMASS...MUCH OF THE PERIOD WILL BE DRY AND EVEN THE SHOWERS SHOULD NOT BE VERY STRONG. BUT MORE IMPORTANTLY...SEASONAL AVERAGE HIGHS/LOWS FOR LATE APRIL ARE THE LOWER 60S (MID 60S SOUTH) AND LOWER 40S RESPECTIVELY...AND MUCH OF THIS PERIOD WILL FEATURE HIGHS IN THE 50S AND LOWS IN THE MID 30S...POSSIBLY COOLER A NIGHT OR TWO IF WINDS ARE LIGHTER. TEMPERATURE ANOMALIES ARE NOT THAT EXTREME THOUGH...SO RECORD COLD IS NOT ANTICIPATED. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * EAST WINDS BETWEEN 10-15KT INTO THIS EVENING. * WEST WINDS GUSTING TO 20 KT TOMORROW. * RAIN OVERSPREADS TAF SITES LATER THIS AFTN THRU TONIGHT. MVFR VSBY UNDER HEAVIER SHOWERS. * LOW END MVFR CIGS DEVELOP...POSSIBLY IFR CONDS DEVELOP BY 3Z THRU DAYBREAK MON. * A SECOND ROUND OF RAIN ARRIVES EARLY MONDAY MORNING. JEE //DISCUSSION...UPDATED 12Z... EAST WINDS CONTINUE TO KEEP THE LOW LEVELS RELATIVELY DRY AND LACK OF LOW CLOUDS...HOWEVER MOISTURE IS CREEPING NORTH ACROSS SOUTHERN IL/IN. WINDS WILL OCCASIONALLY GUST TO 20KT THRU MIDDAY...THEN EXPECT WITH THE ABUNDANCE OF MOISTURE AND RAIN THE GUSTS MAY BECOME LESS FREQUENT WITH SUSTAINED WINDS INCREASING SLIGHTLY TO ARND 12-15KT. AS A LOW PRESSURE LIFTS NORTHEAST TOWARDS THE REGION TONIGHT...CIGS ARE EXPECTED TO LOWER TO MVFR AND LIKELY TO IFR CONDS WITH BASES ARND 800FT AGL BY 3Z. A FEW GUIDANCE MEMBERS SUGGEST CIGS MAY DIP FURTHER TO ARND 400FT AGL BY 6Z AS A BRIEF LULL IN THE PRECIP IS POISED TO LIFT OVERHEAD. AT THIS TIME WILL MENTION VCSH BY 6Z MON...WHICH MAY END UP AS DRIZZLE OR LGT RAIN. CIGS WILL REMAIN IFR THRU DAYBREAK MON...UNTIL A TIGHT GRADIENT RETURNS AND WINDS INCREASE FROM THE WEST/NORTHWEST. THIS SHUD HELP TO LIFT CIGS BACK TO MVFR AND EVENTUALLY VFR CONDS BY LATER MON. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE IN RAIN TIMING...MEDIUM-HIGH CONFIDENCE IN PRECIP COVERAGE THIS EVENING. MEDIUM CONFIDENCE IN PRECIP COVERAGE TONIGHT AND MONDAY MORNING. * MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION AFTER 18Z. * HIGH CONFIDENCE IN CIGS BCMG AT LEAST MVFR AND PSBLY IFR...MEDIUM CONFIDENCE IN TIMING. JEE //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR BECOMING VFR. TUESDAY...SLGT CHANCE PM SHRA...BUT MAINLY VFR. GUSTY WEST WINDS. WEDNESDAY...SLGT CHANCE SHRA. MAINLY VFR. WEST-NORTHWEST WINDS. THURSDAY...VFR. NORTH-NORTHEAST WINDS. FRIDAY...MAINLY VFR. CHC PM SHRA. SATURDAY...MAINLY VFR. BEACHLER && .MARINE... 257 AM CDT LOW PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY LIFT NORTHEAST TOWARDS THE LOWER GREAT LAKES REGION TONIGHT/EARLY MON. GUIDANCE CONTINUES TO INDICATE THE GRADIENT WILL TIGHTEN ACROSS THE LAKE...HOWEVER THIS APPEARS TO BE MORE FOCUSED ALONG THE SOUTHERN TIP OF THE LAKE. WITH THE CONTINUED EASTERLY WINDS...IT IS POSSIBLE MARGINAL SMALL CRAFT CONDITIONS MAY DEVELOP FOR THE ILLINOIS SHORELINE LATER TODAY INTO TONIGHT. THE LOW PRESSURE WILL THEN APPROACH THE LAKE AND BRIEFLY WEAKEN THE GRADIENT EARLY MON. THEN AS THE LOW LIFTS NORTHEAST LATER IN THE DAY MON...IT WILL DEEPEN AND MERGE WITH ANOTHER LOW...WHICH WILL CREATE A TIGHT GRADIENT OVER THE LAKE AND INCREASING WEST/NORTHWEST TUE. AFTER TUE THE DOMINANT WIND DIRECTION WILL BE NORTHWEST THROUGH MID- WEEK...BEFORE RELAXING TO THE WEST. THIS WILL ALLOW HIGHER WAVES TO BE FOCUSED IN THE SOUTHERN HALF OF LAKE MICHIGAN THROUGH MID- WEEK. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
952 AM CDT SUN APR 19 2015 .UPDATE... 952 AM CDT I MADE SOME UPDATES TO THE FORECAST FOR TODAY TO RAISE TEMPERATURES AND PUSH OFF THE TIMING OF THE RAIN CHANCES. WATER VAPOR IMAGERY INDICATES OUR MID/UPPER LEVEL DISTURBANCE OF INTEREST FOR LATER TODAY NOW LIFTING NORTHWARD ACROSS WESTERN KENTUCKY. THIS FEATURE IS CURRENTLY SUPPORTING AN AREA OF NORTHWARD MOVING SHOWERS ACROSS SOUTHERN PORTIONS OF ILLINOIS AND INDIANA. THEREFORE...THIS AREA OF SHOWERS WILL GRADUALLY WORK NORTHWARD ACROSS NORTHEASTERN ILLINOIS AND NORTHWESTERN INDIANA DURING THE AFTERNOON. IT APPEARS THE THREAT FOR THUNDERSTORMS WILL BE VERY LOW WITH THIS ACTIVITY...WITH TRENDS SUGGESTING NO LIGHTNING STRIKES OVER THE PAST FEW HOURS...SO I HAVE REMOVED THE MENTION OF SUCH THIS AFTERNOON. IN ADDITION...WITH THE SLOWER ONSET OF PRECIP TODAY...IT APPEARS TEMPERATURES WILL BE ABLE TO WARM TO NEAR 70 IN MOST AREAS AWAY FROM LAKE MICHIGAN...SO I RAISED HIGH TEMPERATURES TODAY. KJB && .SHORT TERM... 340 AM CDT THROUGH MONDAY... UPPER AIR ANALYSIS EARLY THIS MORNING DEPICTS DEEP UPPER LEVEL LOW PRESSURE NOW PUSHING INTO WESTERN KANSAS. MULTIPLE VORT MAXES ARE ROTATING AROUND THE LOW. THE STRONGEST OF THESE EXIST IN TEXAS AND THROUGH THE CENTRAL PLAINS...WITH SOME SMALLER SCALE WAVES EXTENDING INTO EASTERN MO/FAR WESTERN IL WERE SOME SCATTERED THUNDERSTORMS WERE ONGOING. A NORTHERN STREAM SHORTWAVE IS ENTERING THE NORTHERN PLAINS WITH SOME SHOWERS OUT AHEAD OF IT AS WELL. AT THE SURFACE...THE COLD FRONT THAT PASSED THROUGH NORTHEAST ILLINOIS AND NW INDIANA SATURDAY HAS PUSHED INTO CENTRAL ILLINOIS...BUT HAS LIKELY COMPLETED ITS SOUTHWARD RETREAT AND HAS WASHED OUT OVER THE PAST FEW HOURS. OVER THE LOCAL AREA...MUCH DRIER NE FLOW EXISTS WITH DEWPOINTS IN THE MID TO UPPER 20S IN THE CITY TO NEAR 40 SOUTH...THOUGH DEWPOINTS ARE POOLING ALONG THE FRONT IN THE UPPER 40S JUST SOUTH OF THE LOT CWA. THE SURFACE LOW THAT IS EXPECTED TO DEVELOP FROM THE SOUTHERN STREAM SHORTWAVE IS ALSO TAKING SHAPE OVER THE SOUTHERN STATES WITH A WARM FRONTAL BOUNDARY EXTENDING FROM WESTERN ARKANSAS THROUGH THE LOWER TENNESSEE VALLEY. AN EXPANSION OF LOWER CLOUD TOPS ON IR IMAGERY ALONG AND AHEAD OF THE WARM FRONT IS OCCURRING. LOW LEVEL WARM/MOIST ADVECTION WILL CONTINUE ITS SLOW PROGRESSION NORTHWARD UNDER MODEST SOUTH/SOUTHEAST FLOW. DEEPER MOISTURE/LIFT REALLY HOLD OFF UNTIL THE AFTERNOON PERIOD ACROSS MOST OF THE AREA. A SOMEWHAT COMPLICATED EVOLUTION AS A MAIN SURFACE LOW CENTER IS FORECAST TO STRENGTHEN AS IT LIFTS NORTH THROUGH INDIANA TODAY THEN FURTHER STRENGTHEN TONIGHT INTO MONDAY WHILE SEVERAL ADDITIONAL SURFACE LOWS DEVELOP AND EVENTUALLY MERGE WITH THE MAIN LOW CENTER. THE SURFACE LOW WILL EVENTUALLY BECOME DRIVEN BY A COMBINATION OF THE SW FLOW AHEAD OF THE SOUTHERN STREAM UPPER LOW AND THE NORTHERN STREAM SHORTWAVE. OF NOTE LATER TODAY...EXPECT COVERAGE OF SHOWERS TO INITIALLY BE SLOW GIVEN THE DRIER AIR PLACE...BUT INCREASING ASCENT ALOFT...LOW LEVEL SSE ISENTROPIC ASCENT AHEAD OF THE LOW AND WRAPPING AROUND THE CLOSED CIRCULATION EXTENDING THROUGH 850 AND EVEN 700 MB COMBINED WITH MODEST LOWER LEVEL FGEN SHOULD ALLOW FOR A BLOSSOMING OF SHOWERS ACROSS THE AREA LATER THIS AFTERNOON AND EVENING. THE HIGHEST PWAT AXIS EXPANDS ACROSS INDIANA TODAY BUT SHOULD GET WRAPPED INTO NE ILLINOIS. RAP MOST UNSTABLE CAPE VALUES RELATIVELY LOW BUT DO EXPAND FROM SE TO NW THIS AFTERNOON AND THIS COUPLED WITH THE PUNCH FROM THE DRY SLOT OF THIS SYSTEM MAY ENABLE A FEW T-STORMS AS WELL...SO SOME OF THE SHOWERS WILL HAVE A MODEST KICK TO THEM IN THE MODERATE/HEAVY RAINFALL DEPARTMENT. EXPECT THAT NORTH CENTRAL ILLINOIS MAY BE UNDER A BIT OF SQUEEZE PLAY FROM THESE TWO SYSTEMS...THUS WHILE SHOWERS ARE STILL EXPECTED...HIGHER CONFIDENCE EXISTS IN COVERAGE FARTHER EAST. THIS EVENING THE FIRST MAIN SHORTWAVE WILL BE PASSING NE WHILE THE MAIN SOUTHERN STREAM ENERGY PASSES EAST THROUGH THE OHIO VALLEY...AND THE NORTHERN STREAM SHORTWAVE LAGS BEHIND BACK IN MN/IA. THERE IS ALSO THE LOSS OF DEEPER MOISTURE...THEREFORE EXPECT SHOWERS TO TAPER/END/TURN TO DRIZZLE POSSIBLY OVERNIGHT FOR A TIME. THEN MONDAY MORNING WE GET THE COUPLED UPPER LEVEL FORCING FROM THE NORTHERN STREAM LOW AND SURFACE COLD FRONT WHICH WILL LIKELY BRING ANOTHER ROUND OF SHOWERS MONDAY MORNING. SHOWERS WILL EASE MONDAY AFTERNOON. IT WILL BE QUITE BREEZY/WINDY BEHIND THE FRONT ON MONDAY IN THE COLD ADVECTION REGIME. KMD && .LONG TERM... 340 AM CDT MONDAY NIGHT THROUGH SATURDAY... THE THEME OF THE EXTENDED WILL BE THE UNSEASONABLY COOL WEATHER. A HIGH AMPLITUDE PATTERN WILL BE IN PLACE WITH STRONG UPPER LEVEL RIDGING EXTENDING WELL NORTH INTO THE CANADIAN ROCKIES AND SIMILARLY HIGH AMPLITUDE RIDGING IN THE NORTH ATLANTIC. THAT LEAVES OUR NORTHERN STREAM SHORTWAVE FROM SUNDAY/MONDAY WITH NO WHERE TO GO. THIS WILL KEEP MUCH OF THE EASTERN HALF OF THE COUNTY...INCLUDING OUR REGION...UNDER COOL NORTHWEST FLOW. THIS PATTERN ALSO FAVORED STRONGLY SHEARED OUT AND ELONGATED VORT MAXES TO PIVOT THROUGH BRINGING PERIODS OF SHOWERS. WITH PWAT VALUES QUITE LOW IN THIS AIRMASS...MUCH OF THE PERIOD WILL BE DRY AND EVEN THE SHOWERS SHOULD NOT BE VERY STRONG. BUT MORE IMPORTANTLY...SEASONAL AVERAGE HIGHS/LOWS FOR LATE APRIL ARE THE LOWER 60S (MID 60S SOUTH) AND LOWER 40S RESPECTIVELY...AND MUCH OF THIS PERIOD WILL FEATURE HIGHS IN THE 50S AND LOWS IN THE MID 30S...POSSIBLY COOLER A NIGHT OR TWO IF WINDS ARE LIGHTER. TEMPERATURE ANOMALIES ARE NOT THAT EXTREME THOUGH...SO RECORD COLD IS NOT ANTICIPATED. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * EAST WINDS BETWEEN 7-12KT INCREASING TO 12-15KT WITH GUSTS UP TO 20KT THRU MIDDAY. * WEST WINDS GUSTING TO 20 KT TOMORROW. * RAIN OVERSPREADS TAF SITES LATER THIS AFTN THRU TONIGHT. MVFR VSBY IS PSBL UNDER HEAVIER SHOWERS. * LOW END MVFR CIGS DEVELOP...POSSIBLY IFR CONDS DEVELOP BY 3Z THRU DAYBREAK MON. JEE //DISCUSSION...UPDATED 12Z... EAST WINDS CONTINUE TO KEEP THE LOW LEVELS RELATIVELY DRY AND LACK OF LOW CLOUDS...HOWEVER MOISTURE IS CREEPING NORTH ACROSS SOUTHERN IL/IN. WINDS WILL OCCASIONALLY GUST TO 20KT THRU MIDDAY...THEN EXPECT WITH THE ABUNDANCE OF MOISTURE AND RAIN THE GUSTS MAY BECOME LESS FREQUENT WITH SUSTAINED WINDS INCREASING SLIGHTLY TO ARND 12-15KT. AS A LOW PRESSURE LIFTS NORTHEAST TOWARDS THE REGION TONIGHT...CIGS ARE EXPECTED TO LOWER TO MVFR AND LIKELY TO IFR CONDS WITH BASES ARND 800FT AGL BY 3Z. A FEW GUIDANCE MEMBERS SUGGEST CIGS MAY DIP FURTHER TO ARND 400FT AGL BY 6Z AS A BRIEF LULL IN THE PRECIP IS POISED TO LIFT OVERHEAD. AT THIS TIME WILL MENTION VCSH BY 6Z MON...WHICH MAY END UP AS DRIZZLE OR LGT RAIN. CIGS WILL REMAIN IFR THRU DAYBREAK MON...UNTIL A TIGHT GRADIENT RETURNS AND WINDS INCREASE FROM THE WEST/NORTHWEST. THIS SHUD HELP TO LIFT CIGS BACK TO MVFR AND EVENTUALLY VFR CONDS BY LATER MON. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 14Z... * MEDIUM-HIGH CONFIDENCE IN RAIN TIMING AND COVERAGE. * MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION AFTER 18Z. * HIGH CONFIDENCE IN CIGS BCMG AT LEAST MVFR AND PSBLY IFR...MEDIUM CONFIDENCE IN TIMING. JEE //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR BECOMING VFR. TUESDAY...SLGT CHANCE PM SHRA...BUT MAINLY VFR. GUSTY WEST WINDS. WEDNESDAY...SLGT CHANCE SHRA. MAINLY VFR. WEST-NORTHWEST WINDS. THURSDAY...VFR. NORTH-NORTHEAST WINDS. FRIDAY...MAINLY VFR. CHC PM SHRA. SATURDAY...MAINLY VFR. BEACHLER && .MARINE... 257 AM CDT LOW PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY LIFT NORTHEAST TOWARDS THE LOWER GREAT LAKES REGION TONIGHT/EARLY MON. GUIDANCE CONTINUES TO INDICATE THE GRADIENT WILL TIGHTEN ACROSS THE LAKE...HOWEVER THIS APPEARS TO BE MORE FOCUSED ALONG THE SOUTHERN TIP OF THE LAKE. WITH THE CONTINUED EASTERLY WINDS...IT IS POSSIBLE MARGINAL SMALL CRAFT CONDITIONS MAY DEVELOP FOR THE ILLINOIS SHORELINE LATER TODAY INTO TONIGHT. THE LOW PRESSURE WILL THEN APPROACH THE LAKE AND BRIEFLY WEAKEN THE GRADIENT EARLY MON. THEN AS THE LOW LIFTS NORTHEAST LATER IN THE DAY MON...IT WILL DEEPEN AND MERGE WITH ANOTHER LOW...WHICH WILL CREATE A TIGHT GRADIENT OVER THE LAKE AND INCREASING WEST/NORTHWEST TUE. AFTER TUE THE DOMINANT WIND DIRECTION WILL BE NORTHWEST THROUGH MID- WEEK...BEFORE RELAXING TO THE WEST. THIS WILL ALLOW HIGHER WAVES TO BE FOCUSED IN THE SOUTHERN HALF OF LAKE MICHIGAN THROUGH MID- WEEK. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
856 AM CDT SUN APR 19 2015 .SHORT TERM... 340 AM CDT THROUGH MONDAY... UPPER AIR ANALYSIS EARLY THIS MORNING DEPICTS DEEP UPPER LEVEL LOW PRESSURE NOW PUSHING INTO WESTERN KANSAS. MULTIPLE VORT MAXES ARE ROTATING AROUND THE LOW. THE STRONGEST OF THESE EXIST IN TEXAS AND THROUGH THE CENTRAL PLAINS...WITH SOME SMALLER SCALE WAVES EXTENDING INTO EASTERN MO/FAR WESTERN IL WERE SOME SCATTERED THUNDERSTORMS WERE ONGOING. A NORTHERN STREAM SHORTWAVE IS ENTERING THE NORTHERN PLAINS WITH SOME SHOWERS OUT AHEAD OF IT AS WELL. AT THE SURFACE...THE COLD FRONT THAT PASSED THROUGH NORTHEAST ILLINOIS AND NW INDIANA SATURDAY HAS PUSHED INTO CENTRAL ILLINOIS...BUT HAS LIKELY COMPLETED ITS SOUTHWARD RETREAT AND HAS WASHED OUT OVER THE PAST FEW HOURS. OVER THE LOCAL AREA...MUCH DRIER NE FLOW EXISTS WITH DEWPOINTS IN THE MID TO UPPER 20S IN THE CITY TO NEAR 40 SOUTH...THOUGH DEWPOINTS ARE POOLING ALONG THE FRONT IN THE UPPER 40S JUST SOUTH OF THE LOT CWA. THE SURFACE LOW THAT IS EXPECTED TO DEVELOP FROM THE SOUTHERN STREAM SHORTWAVE IS ALSO TAKING SHAPE OVER THE SOUTHERN STATES WITH A WARM FRONTAL BOUNDARY EXTENDING FROM WESTERN ARKANSAS THROUGH THE LOWER TENNESSEE VALLEY. AN EXPANSION OF LOWER CLOUD TOPS ON IR IMAGERY ALONG AND AHEAD OF THE WARM FRONT IS OCCURRING. LOW LEVEL WARM/MOIST ADVECTION WILL CONTINUE ITS SLOW PROGRESSION NORTHWARD UNDER MODEST SOUTH/SOUTHEAST FLOW. DEEPER MOISTURE/LIFT REALLY HOLD OFF UNTIL THE AFTERNOON PERIOD ACROSS MOST OF THE AREA. A SOMEWHAT COMPLICATED EVOLUTION AS A MAIN SURFACE LOW CENTER IS FORECAST TO STRENGTHEN AS IT LIFTS NORTH THROUGH INDIANA TODAY THEN FURTHER STRENGTHEN TONIGHT INTO MONDAY WHILE SEVERAL ADDITIONAL SURFACE LOWS DEVELOP AND EVENTUALLY MERGE WITH THE MAIN LOW CENTER. THE SURFACE LOW WILL EVENTUALLY BECOME DRIVEN BY A COMBINATION OF THE SW FLOW AHEAD OF THE SOUTHERN STREAM UPPER LOW AND THE NORTHERN STREAM SHORTWAVE. OF NOTE LATER TODAY...EXPECT COVERAGE OF SHOWERS TO INITIALLY BE SLOW GIVEN THE DRIER AIR PLACE...BUT INCREASING ASCENT ALOFT...LOW LEVEL SSE ISENTROPIC ASCENT AHEAD OF THE LOW AND WRAPPING AROUND THE CLOSED CIRCULATION EXTENDING THROUGH 850 AND EVEN 700 MB COMBINED WITH MODEST LOWER LEVEL FGEN SHOULD ALLOW FOR A BLOSSOMING OF SHOWERS ACROSS THE AREA LATER THIS AFTERNOON AND EVENING. THE HIGHEST PWAT AXIS EXPANDS ACROSS INDIANA TODAY BUT SHOULD GET WRAPPED INTO NE ILLINOIS. RAP MOST UNSTABLE CAPE VALUES RELATIVELY LOW BUT DO EXPAND FROM SE TO NW THIS AFTERNOON AND THIS COUPLED WITH THE PUNCH FROM THE DRY SLOT OF THIS SYSTEM MAY ENABLE A FEW T-STORMS AS WELL...SO SOME OF THE SHOWERS WILL HAVE A MODEST KICK TO THEM IN THE MODERATE/HEAVY RAINFALL DEPARTMENT. EXPECT THAT NORTH CENTRAL ILLINOIS MAY BE UNDER A BIT OF SQUEEZE PLAY FROM THESE TWO SYSTEMS...THUS WHILE SHOWERS ARE STILL EXPECTED...HIGHER CONFIDENCE EXISTS IN COVERAGE FARTHER EAST. THIS EVENING THE FIRST MAIN SHORTWAVE WILL BE PASSING NE WHILE THE MAIN SOUTHERN STREAM ENERGY PASSES EAST THROUGH THE OHIO VALLEY...AND THE NORTHERN STREAM SHORTWAVE LAGS BEHIND BACK IN MN/IA. THERE IS ALSO THE LOSS OF DEEPER MOISTURE...THEREFORE EXPECT SHOWERS TO TAPER/END/TURN TO DRIZZLE POSSIBLY OVERNIGHT FOR A TIME. THEN MONDAY MORNING WE GET THE COUPLED UPPER LEVEL FORCING FROM THE NORTHERN STREAM LOW AND SURFACE COLD FRONT WHICH WILL LIKELY BRING ANOTHER ROUND OF SHOWERS MONDAY MORNING. SHOWERS WILL EASE MONDAY AFTERNOON. IT WILL BE QUITE BREEZY/WINDY BEHIND THE FRONT ON MONDAY IN THE COLD ADVECTION REGIME. KMD && .LONG TERM... 340 AM CDT MONDAY NIGHT THROUGH SATURDAY... THE THEME OF THE EXTENDED WILL BE THE UNSEASONABLY COOL WEATHER. A HIGH AMPLITUDE PATTERN WILL BE IN PLACE WITH STRONG UPPER LEVEL RIDGING EXTENDING WELL NORTH INTO THE CANADIAN ROCKIES AND SIMILARLY HIGH AMPLITUDE RIDGING IN THE NORTH ATLANTIC. THAT LEAVES OUR NORTHERN STREAM SHORTWAVE FROM SUNDAY/MONDAY WITH NO WHERE TO GO. THIS WILL KEEP MUCH OF THE EASTERN HALF OF THE COUNTY...INCLUDING OUR REGION...UNDER COOL NORTHWEST FLOW. THIS PATTERN ALSO FAVORED STRONGLY SHEARED OUT AND ELONGATED VORT MAXES TO PIVOT THROUGH BRINGING PERIODS OF SHOWERS. WITH PWAT VALUES QUITE LOW IN THIS AIRMASS...MUCH OF THE PERIOD WILL BE DRY AND EVEN THE SHOWERS SHOULD NOT BE VERY STRONG. BUT MORE IMPORTANTLY...SEASONAL AVERAGE HIGHS/LOWS FOR LATE APRIL ARE THE LOWER 60S (MID 60S SOUTH) AND LOWER 40S RESPECTIVELY...AND MUCH OF THIS PERIOD WILL FEATURE HIGHS IN THE 50S AND LOWS IN THE MID 30S...POSSIBLY COOLER A NIGHT OR TWO IF WINDS ARE LIGHTER. TEMPERATURE ANOMALIES ARE NOT THAT EXTREME THOUGH...SO RECORD COLD IS NOT ANTICIPATED. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * EAST WINDS BETWEEN 7-12KT INCREASING TO 12-15KT WITH GUSTS UP TO 20KT THRU MIDDAY. * WEST WINDS GUSTING TO 20 KT TOMORROW. * RAIN OVERSPREADS TAF SITES LATER THIS AFTN THRU TONIGHT. MVFR VSBY IS PSBL UNDER HEAVIER SHOWERS. * LOW END MVFR CIGS DEVELOP...POSSIBLY IFR CONDS DEVELOP BY 3Z THRU DAYBREAK MON. JEE //DISCUSSION...UPDATED 12Z... EAST WINDS CONTINUE TO KEEP THE LOW LEVELS RELATIVELY DRY AND LACK OF LOW CLOUDS...HOWEVER MOISTURE IS CREEPING NORTH ACROSS SOUTHERN IL/IN. WINDS WILL OCCASIONALLY GUST TO 20KT THRU MIDDAY...THEN EXPECT WITH THE ABUNDANCE OF MOISTURE AND RAIN THE GUSTS MAY BECOME LESS FREQUENT WITH SUSTAINED WINDS INCREASING SLIGHTLY TO ARND 12-15KT. AS A LOW PRESSURE LIFTS NORTHEAST TOWARDS THE REGION TONIGHT...CIGS ARE EXPECTED TO LOWER TO MVFR AND LIKELY TO IFR CONDS WITH BASES ARND 800FT AGL BY 3Z. A FEW GUIDANCE MEMBERS SUGGEST CIGS MAY DIP FURTHER TO ARND 400FT AGL BY 6Z AS A BRIEF LULL IN THE PRECIP IS POISED TO LIFT OVERHEAD. AT THIS TIME WILL MENTION VCSH BY 6Z MON...WHICH MAY END UP AS DRIZZLE OR LGT RAIN. CIGS WILL REMAIN IFR THRU DAYBREAK MON...UNTIL A TIGHT GRADIENT RETURNS AND WINDS INCREASE FROM THE WEST/NORTHWEST. THIS SHUD HELP TO LIFT CIGS BACK TO MVFR AND EVENTUALLY VFR CONDS BY LATER MON. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 14Z... * MEDIUM-HIGH CONFIDENCE IN RAIN TIMING AND COVERAGE. * MEDIUM CONFIDENCE IN WIND SPEED AND DIRECTION AFTER 18Z. * HIGH CONFIDENCE IN CIGS BCMG AT LEAST MVFR AND PSBLY IFR...MEDIUM CONFIDENCE IN TIMING. JEE //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR BECOMING VFR. TUESDAY...SLGT CHANCE PM SHRA...BUT MAINLY VFR. GUSTY WEST WINDS. WEDNESDAY...SLGT CHANCE SHRA. MAINLY VFR. WEST-NORTHWEST WINDS. THURSDAY...VFR. NORTH-NORTHEAST WINDS. FRIDAY...MAINLY VFR. CHC PM SHRA. SATURDAY...MAINLY VFR. BEACHLER && .MARINE... 257 AM CDT LOW PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY LIFT NORTHEAST TOWARDS THE LOWER GREAT LAKES REGION TONIGHT/EARLY MON. GUIDANCE CONTINUES TO INDICATE THE GRADIENT WILL TIGHTEN ACROSS THE LAKE...HOWEVER THIS APPEARS TO BE MORE FOCUSED ALONG THE SOUTHERN TIP OF THE LAKE. WITH THE CONTINUED EASTERLY WINDS...IT IS POSSIBLE MARGINAL SMALL CRAFT CONDITIONS MAY DEVELOP FOR THE ILLINOIS SHORELINE LATER TODAY INTO TONIGHT. THE LOW PRESSURE WILL THEN APPROACH THE LAKE AND BRIEFLY WEAKEN THE GRADIENT EARLY MON. THEN AS THE LOW LIFTS NORTHEAST LATER IN THE DAY MON...IT WILL DEEPEN AND MERGE WITH ANOTHER LOW...WHICH WILL CREATE A TIGHT GRADIENT OVER THE LAKE AND INCREASING WEST/NORTHWEST TUE. AFTER TUE THE DOMINANT WIND DIRECTION WILL BE NORTHWEST THROUGH MID- WEEK...BEFORE RELAXING TO THE WEST. THIS WILL ALLOW HIGHER WAVES TO BE FOCUSED IN THE SOUTHERN HALF OF LAKE MICHIGAN THROUGH MID- WEEK. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
647 AM CDT SUN APR 19 2015 .SHORT TERM... 340 AM CDT THROUGH MONDAY... UPPER AIR ANALYSIS EARLY THIS MORNING DEPICTS DEEP UPPER LEVEL LOW PRESSURE NOW PUSHING INTO WESTERN KANSAS. MULTIPLE VORT MAXES ARE ROTATING AROUND THE LOW. THE STRONGEST OF THESE EXIST IN TEXAS AND THROUGH THE CENTRAL PLAINS...WITH SOME SMALLER SCALE WAVES EXTENDING INTO EASTERN MO/FAR WESTERN IL WERE SOME SCATTERED THUNDERSTORMS WERE ONGOING. A NORTHERN STREAM SHORTWAVE IS ENTERING THE NORTHERN PLAINS WITH SOME SHOWERS OUT AHEAD OF IT AS WELL. AT THE SURFACE...THE COLD FRONT THAT PASSED THROUGH NORTHEAST ILLINOIS AND NW INDIANA SATURDAY HAS PUSHED INTO CENTRAL ILLINOIS...BUT HAS LIKELY COMPLETED ITS SOUTHWARD RETREAT AND HAS WASHED OUT OVER THE PAST FEW HOURS. OVER THE LOCAL AREA...MUCH DRIER NE FLOW EXISTS WITH DEWPOINTS IN THE MID TO UPPER 20S IN THE CITY TO NEAR 40 SOUTH...THOUGH DEWPOINTS ARE POOLING ALONG THE FRONT IN THE UPPER 40S JUST SOUTH OF THE LOT CWA. THE SURFACE LOW THAT IS EXPECTED TO DEVELOP FROM THE SOUTHERN STREAM SHORTWAVE IS ALSO TAKING SHAPE OVER THE SOUTHERN STATES WITH A WARM FRONTAL BOUNDARY EXTENDING FROM WESTERN ARKANSAS THROUGH THE LOWER TENNESSEE VALLEY. AN EXPANSION OF LOWER CLOUD TOPS ON IR IMAGERY ALONG AND AHEAD OF THE WARM FRONT IS OCCURRING. LOW LEVEL WARM/MOIST ADVECTION WILL CONTINUE ITS SLOW PROGRESSION NORTHWARD UNDER MODEST SOUTH/SOUTHEAST FLOW. DEEPER MOISTURE/LIFT REALLY HOLD OFF UNTIL THE AFTERNOON PERIOD ACROSS MOST OF THE AREA. A SOMEWHAT COMPLICATED EVOLUTION AS A MAIN SURFACE LOW CENTER IS FORECAST TO STRENGTHEN AS IT LIFTS NORTH THROUGH INDIANA TODAY THEN FURTHER STRENGTHEN TONIGHT INTO MONDAY WHILE SEVERAL ADDITIONAL SURFACE LOWS DEVELOP AND EVENTUALLY MERGE WITH THE MAIN LOW CENTER. THE SURFACE LOW WILL EVENTUALLY BECOME DRIVEN BY A COMBINATION OF THE SW FLOW AHEAD OF THE SOUTHERN STREAM UPPER LOW AND THE NORTHERN STREAM SHORTWAVE. OF NOTE LATER TODAY...EXPECT COVERAGE OF SHOWERS TO INITIALLY BE SLOW GIVEN THE DRIER AIR PLACE...BUT INCREASING ASCENT ALOFT...LOW LEVEL SSE ISENTROPIC ASCENT AHEAD OF THE LOW AND WRAPPING AROUND THE CLOSED CIRCULATION EXTENDING THROUGH 850 AND EVEN 700 MB COMBINED WITH MODEST LOWER LEVEL FGEN SHOULD ALLOW FOR A BLOSSOMING OF SHOWERS ACROSS THE AREA LATER THIS AFTERNOON AND EVENING. THE HIGHEST PWAT AXIS EXPANDS ACROSS INDIANA TODAY BUT SHOULD GET WRAPPED INTO NE ILLINOIS. RAP MOST UNSTABLE CAPE VALUES RELATIVELY LOW BUT DO EXPAND FROM SE TO NW THIS AFTERNOON AND THIS COUPLED WITH THE PUNCH FROM THE DRY SLOT OF THIS SYSTEM MAY ENABLE A FEW T-STORMS AS WELL...SO SOME OF THE SHOWERS WILL HAVE A MODEST KICK TO THEM IN THE MODERATE/HEAVY RAINFALL DEPARTMENT. EXPECT THAT NORTH CENTRAL ILLINOIS MAY BE UNDER A BIT OF SQUEEZE PLAY FROM THESE TWO SYSTEMS...THUS WHILE SHOWERS ARE STILL EXPECTED...HIGHER CONFIDENCE EXISTS IN COVERAGE FARTHER EAST. THIS EVENING THE FIRST MAIN SHORTWAVE WILL BE PASSING NE WHILE THE MAIN SOUTHERN STREAM ENERGY PASSES EAST THROUGH THE OHIO VALLEY...AND THE NORTHERN STREAM SHORTWAVE LAGS BEHIND BACK IN MN/IA. THERE IS ALSO THE LOSS OF DEEPER MOISTURE...THEREFORE EXPECT SHOWERS TO TAPER/END/TURN TO DRIZZLE POSSIBLY OVERNIGHT FOR A TIME. THEN MONDAY MORNING WE GET THE COUPLED UPPER LEVEL FORCING FROM THE NORTHERN STREAM LOW AND SURFACE COLD FRONT WHICH WILL LIKELY BRING ANOTHER ROUND OF SHOWERS MONDAY MORNING. SHOWERS WILL EASE MONDAY AFTERNOON. IT WILL BE QUITE BREEZY/WINDY BEHIND THE FRONT ON MONDAY IN THE COLD ADVECTION REGIME. KMD && .LONG TERM... 340 AM CDT MONDAY NIGHT THROUGH SATURDAY... THE THEME OF THE EXTENDED WILL BE THE UNSEASONABLY COOL WEATHER. A HIGH AMPLITUDE PATTERN WILL BE IN PLACE WITH STRONG UPPER LEVEL RIDGING EXTENDING WELL NORTH INTO THE CANADIAN ROCKIES AND SIMILARLY HIGH AMPLITUDE RIDGING IN THE NORTH ATLANTIC. THAT LEAVES OUR NORTHERN STREAM SHORTWAVE FROM SUNDAY/MONDAY WITH NO WHERE TO GO. THIS WILL KEEP MUCH OF THE EASTERN HALF OF THE COUNTY...INCLUDING OUR REGION...UNDER COOL NORTHWEST FLOW. THIS PATTERN ALSO FAVORED STRONGLY SHEARED OUT AND ELONGATED VORT MAXES TO PIVOT THROUGH BRINGING PERIODS OF SHOWERS. WITH PWAT VALUES QUITE LOW IN THIS AIRMASS...MUCH OF THE PERIOD WILL BE DRY AND EVEN THE SHOWERS SHOULD NOT BE VERY STRONG. BUT MORE IMPORTANTLY...SEASONAL AVERAGE HIGHS/LOWS FOR LATE APRIL ARE THE LOWER 60S (MID 60S SOUTH) AND LOWER 40S RESPECTIVELY...AND MUCH OF THIS PERIOD WILL FEATURE HIGHS IN THE 50S AND LOWS IN THE MID 30S...POSSIBLY COOLER A NIGHT OR TWO IF WINDS ARE LIGHTER. TEMPERATURE ANOMALIES ARE NOT THAT EXTREME THOUGH...SO RECORD COLD IS NOT ANTICIPATED. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * EAST WINDS BETWEEN 7-12KT INCREASING TO 12-15KT WITH GUSTS UP TO 20KT THRU MIDDAY. * WINDS TURN NORTH LATE TONIGHT...THEN NORTHWEST EARLY MON. * RAIN OVERSPREADS TAF SITES LATER THIS AFTN THRU TONIGHT. * LOW END MVFR CIGS DEVELOP...POSSIBLY IFR CONDS DEVELOP BY 3Z THRU DAYBREAK MON. BEACHLER //DISCUSSION...UPDATED 12Z... EAST WINDS CONTINUE TO KEEP THE LOW LEVELS RELATIVELY DRY AND LACK OF LOW CLOUDS...HOWEVER MOISTURE IS CREEPING NORTH ACROSS SOUTHERN IL/IN. WINDS WILL OCCASIONALLY GUST TO 20KT THRU MIDDAY...THEN EXPECT WITH THE ABUNDANCE OF MOISTURE AND RAIN THE GUSTS MAY BECOME LESS FREQUENT WITH SUSTAINED WINDS INCREASING SLIGHTLY TO ARND 12-15KT. AS A LOW PRESSURE LIFTS NORTHEAST TOWARDS THE REGION TONIGHT...CIGS ARE EXPECTED TO LOWER TO MVFR AND LIKELY TO IFR CONDS WITH BASES ARND 800FT AGL BY 3Z. A FEW GUIDANCE MEMBERS SUGGEST CIGS MAY DIP FURTHER TO ARND 400FT AGL BY 6Z AS A BRIEF LULL IN THE PRECIP IS POISED TO LIFT OVERHEAD. AT THIS TIME WILL MENTION VCSH BY 6Z MON...WHICH MAY END UP AS DRIZZLE OR LGT RAIN. CIGS WILL REMAIN IFR THRU DAYBREAK MON...UNTIL A TIGHT GRADIENT RETURNS AND WINDS INCREASE FROM THE WEST/NORTHWEST. THIS SHUD HELP TO LIFT CIGS BACK TO MVFR AND EVENTUALLY VFR CONDS BY LATER MON. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH CONFIDENCE IN ALL ELEMENTS THROUGH 18Z...MEDIUM CONFIDENCE IN WIND DIR/SPEED AFT 18Z. * MEDIUM CONFIDENCE IN PRECIP TIMING/COVERAGE. * HIGH CONFIDENCE IN CIGS DIMINISHING TO AT LEAST MVFR CONDS AFT 21Z...AND MEDIUM CONFIDENCE IN CIGS BECOMING IFR AFT 3Z MON. BEACHLER //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR BECOMING VFR. TUESDAY...SLGT CHANCE PM SHRA...BUT MAINLY VFR. GUSTY WEST WINDS. WEDNESDAY...SLGT CHANCE SHRA. MAINLY VFR. WEST-NORTHWEST WINDS. THURSDAY...VFR. NORTH-NORTHEAST WINDS. FRIDAY...MAINLY VFR. CHC PM SHRA. SATURDAY...MAINLY VFR. BEACHLER && .MARINE... 257 AM CDT LOW PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY LIFT NORTHEAST TOWARDS THE LOWER GREAT LAKES REGION TONIGHT/EARLY MON. GUIDANCE CONTINUES TO INDICATE THE GRADIENT WILL TIGHTEN ACROSS THE LAKE...HOWEVER THIS APPEARS TO BE MORE FOCUSED ALONG THE SOUTHERN TIP OF THE LAKE. WITH THE CONTINUED EASTERLY WINDS...IT IS POSSIBLE MARGINAL SMALL CRAFT CONDITIONS MAY DEVELOP FOR THE ILLINOIS SHORELINE LATER TODAY INTO TONIGHT. THE LOW PRESSURE WILL THEN APPROACH THE LAKE AND BRIEFLY WEAKEN THE GRADIENT EARLY MON. THEN AS THE LOW LIFTS NORTHEAST LATER IN THE DAY MON...IT WILL DEEPEN AND MERGE WITH ANOTHER LOW...WHICH WILL CREATE A TIGHT GRADIENT OVER THE LAKE AND INCREASING WEST/NORTHWEST TUE. AFTER TUE THE DOMINANT WIND DIRECTION WILL BE NORTHWEST THROUGH MID- WEEK...BEFORE RELAXING TO THE WEST. THIS WILL ALLOW HIGHER WAVES TO BE FOCUSED IN THE SOUTHERN HALF OF LAKE MICHIGAN THROUGH MID- WEEK. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
642 AM CDT SUN APR 19 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 328 AM CDT SUN APR 19 2015 LATEST WATER VAPOR IMAGERY CONTINUES TO SHOW CLOSED UPPER LOW OVER EASTERN COLORADO, WITH LEAD SHORT-WAVE ROTATING AROUND THIS FEATURE ACROSS ARKANSAS/LOUISIANA. AS THIS WAVE LIFTS NORTHWARD, PRECIP WILL EVENTUALLY SPREAD INTO CENTRAL ILLINOIS TODAY. 07Z/2AM RADAR MOSAIC SHOWS DRY CONDITIONS ACROSS THE ENTIRE KILX CWA: HOWEVER, SHOWERS ARE BEGINNING TO DEVELOP AND BECOME MORE WIDESPREAD FURTHER SOUTH ACROSS WESTERN KENTUCKY AND FAR SOUTHERN ILLINOIS. BASED ON RADAR TIMING TOOLS AND LATEST HRRR FORECAST, THINK SCATTERED SHOWERS WILL ARRIVE SOUTH OF I-70 OVER THE NEXT COUPLE OF HOURS, THEN WILL SPREAD NORTHWARD TOWARD THE I-74 CORRIDOR BY MIDDAY. HAVE ADJUSTED POPS TO ACCOUNT FOR THE SLOWER ARRIVAL OF PRECIP DURING THE MORNING, THEN HAVE GONE WITH CATEGORICAL POPS ACROSS THE BOARD THIS AFTERNOON. ASIDE FROM SOME SBCAPES OF AROUND 1000J/KG ACROSS THE FAR SE CWA, FORECAST SOUNDINGS REMAIN FAIRLY STABLE TODAY. AS A RESULT, AM EXPECTING MAINLY SHOWERS WITH JUST A FEW EMBEDDED THUNDERSTORMS. DUE TO CLOUD COVER AND PRECIP, HIGH TEMPERATURES WILL BE SEVERAL DEGREES COOLER THAN IN RECENT DAYS, WITH READINGS MAINLY IN THE 60S. WARMEST TEMPS OF AROUND 70 WILL BE FOCUSED ALONG/WEST OF THE ILLINOIS RIVER WHERE PRECIP WILL BE SLOWEST TO ARRIVE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 328 AM CDT SUN APR 19 2015 LEAD SHORT-WAVE WILL LIFT INTO NORTHERN ILLINOIS/INDIANA BY EARLY EVENING, LIKELY LEADING TO A TEMPORARY LULL IN THE SHOWERS. MEANWHILE, THE MAIN UPPER LOW WILL GET A SOLID PUSH EASTWARD AND WILL ARRIVE ACROSS ILLINOIS LATER TONIGHT INTO MONDAY MORNING. SHOWERS AND PERHAPS A THUNDERSTORM WILL ACCOMPANY THIS FEATURE, SO WILL CONTINUE LIKELY POPS TONIGHT THROUGH MONDAY MORNING. ONCE THE 500MB VORT MAX AND THE ASSOCIATED SURFACE COLD FRONT PASS TO THE EAST, RAIN CHANCES WILL COME TO AN END BY MONDAY AFTERNOON. THANKS TO A TIGHT PRESSURE GRADIENT BEHIND THE DEPARTING FRONT, STRONG W/NW WINDS GUSTING TO BETWEEN 25 AND 30 MPH WILL DEVELOP ON MONDAY. THE WINDS WILL SUBSIDE FOR A TIME MONDAY NIGHT, BUT WILL ONCE AGAIN INCREASE MARKEDLY DURING THE DAY TUESDAY. HIGH TEMPERATURES BOTH DAYS WILL REMAIN IN THE LOWER 60S, WHILE OVERNIGHT LOWS DIP INTO THE UPPER 30S AND LOWER 40S. 00Z APR 19 MODELS HAVE COME INTO MUCH BETTER AGREEMENT CONCERNING THE EXTENDED FORECAST, WITH CONSENSUS FEATURING A CHILLY AND LARGELY DRY WEEK AHEAD. BOTH THE GFS AND ECMWF INDICATE A WEAK COLD FRONT WILL PASS THROUGH CENTRAL ILLINOIS TUESDAY NIGHT INTO WEDNESDAY: HOWEVER, THEY DISAGREE ON HOW MUCH PRECIP IT WILL GENERATE. THE GFS IS SLIGHTLY WETTER AND FASTER WITH FROPA, WHILE THE ECMWF IS DRIER AND ABOUT 6 HOURS SLOWER WITH THE FRONT. DUE TO THE STRONG NORTHWESTERLY UPPER FLOW PATTERN IN PLACE ACROSS THE MIDWEST, THINK THE FASTER GFS IS THE WAY TO GO WITH TIMING, BUT THINK THE DRIER ECMWF IS BETTER WITH QPF AS DEEP MOISTURE WILL BE LACKING WITH THIS FEATURE. AS A RESULT, HAVE OPTED TO CARRY LOW CHANCE POPS EVERYWHERE TUESDAY NIGHT, THEN ONLY ACROSS THE SE CWA ON WEDNESDAY. ONCE THE FRONT PASSES, A COOL/CANADIAN AIRMASS WILL SETTLE INTO THE REGION FOR THE MIDDLE AND END OF THE WEEK. HIGH TEMPERATURES WILL STRUGGLE TO REACH THE 60 DEGREE MARK ON BOTH WEDNESDAY AND THURSDAY, WHILE LOWS DROP INTO THE 30S. COLDEST MORNING MAY END UP BEING FRIDAY MORNING, WHEN RIDGE OF HIGH PRESSURE IS OVERHEAD AND WINDS WILL BE LIGHTEST. WILL NEED TO KEEP AN EYE ON TEMPS, AS FROST ADVISORIES WILL BE POSSIBLE ACROSS PARTS OF CENTRAL/SOUTHEAST ILLINOIS LATER THIS WEEK. AFTER THAT, ANOTHER SYSTEM WILL APPROACH FROM THE SOUTHWEST BY THE END OF THE WEEK: HOWEVER, ITS INFLUENCE LIKELY WILL NOT BE FELT UNTIL FRIDAY NIGHT/SATURDAY AT THE EARLIEST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 542 AM CDT SUN APR 19 2015 MID AND HIGH CLOUDS WILL CONTINUE OVER THE AREA THIS MORNING, EFFECTING ALL TAF SITES UNTIL THE PCPN MOVES INTO THE SITES. WILL START ALL SITES WITH VCSH AS THE PCPN MOVES NORTHWARD AND INITIALLY SATURATES THE LOWER LEVELS, DURING THE MORNING HOURS. THEN BETWEEN 10AM AND NOON, PCPN WILL BECOME MORE DOMINATE AND STEADY. TIMING OF ONSET OF PCPN WAS TAKEN FROM A BLEND OF THE BUFKIT DATA, NAM12, HRRR, AND RADAR TRENDS. MVFR CIGS AND VIS WILL ARRIVE WITH THE RAIN AND CONTINUE THROUGH REST OF TAF VALID PERIOD. PCPN COULD LET UP SOME LATE THIS EVENING, SO HAVE ADDED ANOTHER LINE FOR VCSH AFTER THE BULK OF THE RAIN MOVES THROUGH, AND BEFORE THE NEXT BATCH ARRIVES LATE TONIGHT/EARLY TOMORROW MORNING. WINDS WILL BE EASTERLY TO START, BUT THEN BECOME SOUTHEASTERLY AS THE SYSTEM GET CLOSER TO THE SITES. WITH THE SURFACE LOW PRESSURE AREA MOVING RIGHT OVER THE TAFS, WINDS WILL BE VARIABLE, ENDING AT WEST TO SOUTHWEST LATER TONIGHT. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BARNES LONG TERM...BARNES AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
420 AM CDT SUN APR 19 2015 .SHORT TERM... 340 AM CDT THROUGH MONDAY... UPPER AIR ANALYSIS EARLY THIS MORNING DEPICTS DEEP UPPER LEVEL LOW PRESSURE NOW PUSHING INTO WESTERN KANSAS. MULTIPLE VORT MAXES ARE ROTATING AROUND THE LOW. THE STRONGEST OF THESE EXIST IN TEXAS AND THROUGH THE CENTRAL PLAINS...WITH SOME SMALLER SCALE WAVES EXTENDING INTO EASTERN MO/FAR WESTERN IL WERE SOME SCATTERED THUNDERSTORMS WERE ONGOING. A NORTHERN STREAM SHORTWAVE IS ENTERING THE NORTHERN PLAINS WITH SOME SHOWERS OUT AHEAD OF IT AS WELL. AT THE SURFACE...THE COLD FRONT THAT PASSED THROUGH NORTHEAST ILLINOIS AND NW INDIANA SATURDAY HAS PUSHED INTO CENTRAL ILLINOIS...BUT HAS LIKELY COMPLETED ITS SOUTHWARD RETREAT AND HAS WASHED OUT OVER THE PAST FEW HOURS. OVER THE LOCAL AREA...MUCH DRIER NE FLOW EXISTS WITH DEWPOINTS IN THE MID TO UPPER 20S IN THE CITY TO NEAR 40 SOUTH...THOUGH DEWPOINTS ARE POOLING ALONG THE FRONT IN THE UPPER 40S JUST SOUTH OF THE LOT CWA. THE SURFACE LOW THAT IS EXPECTED TO DEVELOP FROM THE SOUTHERN STREAM SHORTWAVE IS ALSO TAKING SHAPE OVER THE SOUTHERN STATES WITH A WARM FRONTAL BOUNDARY EXTENDING FROM WESTERN ARKANSAS THROUGH THE LOWER TENNESSEE VALLEY. AN EXPANSION OF LOWER CLOUD TOPS ON IR IMAGERY ALONG AND AHEAD OF THE WARM FRONT IS OCCURRING. LOW LEVEL WARM/MOIST ADVECTION WILL CONTINUE ITS SLOW PROGRESSION NORTHWARD UNDER MODEST SOUTH/SOUTHEAST FLOW. DEEPER MOISTURE/LIFT REALLY HOLD OFF UNTIL THE AFTERNOON PERIOD ACROSS MOST OF THE AREA. A SOMEWHAT COMPLICATED EVOLUTION AS A MAIN SURFACE LOW CENTER IS FORECAST TO STRENGTHEN AS IT LIFTS NORTH THROUGH INDIANA TODAY THEN FURTHER STRENGTHEN TONIGHT INTO MONDAY WHILE SEVERAL ADDITIONAL SURFACE LOWS DEVELOP AND EVENTUALLY MERGE WITH THE MAIN LOW CENTER. THE SURFACE LOW WILL EVENTUALLY BECOME DRIVEN BY A COMBINATION OF THE SW FLOW AHEAD OF THE SOUTHERN STREAM UPPER LOW AND THE NORTHERN STREAM SHORTWAVE. OF NOTE LATER TODAY...EXPECT COVERAGE OF SHOWERS TO INITIALLY BE SLOW GIVEN THE DRIER AIR PLACE...BUT INCREASING ASCENT ALOFT...LOW LEVEL SSE ISENTROPIC ASCENT AHEAD OF THE LOW AND WRAPPING AROUND THE CLOSED CIRCULATION EXTENDING THROUGH 850 AND EVEN 700 MB COMBINED WITH MODEST LOWER LEVEL FGEN SHOULD ALLOW FOR A BLOSSOMING OF SHOWERS ACROSS THE AREA LATER THIS AFTERNOON AND EVENING. THE HIGHEST PWAT AXIS EXPANDS ACROSS INDIANA TODAY BUT SHOULD GET WRAPPED INTO NE ILLINOIS. RAP MOST UNSTABLE CAPE VALUES RELATIVELY LOW BUT DO EXPAND FROM SE TO NW THIS AFTERNOON AND THIS COUPLED WITH THE PUNCH FROM THE DRY SLOT OF THIS SYSTEM MAY ENABLE A FEW T-STORMS AS WELL...SO SOME OF THE SHOWERS WILL HAVE A MODEST KICK TO THEM IN THE MODERATE/HEAVY RAINFALL DEPARTMENT. EXPECT THAT NORTH CENTRAL ILLINOIS MAY BE UNDER A BIT OF SQUEEZE PLAY FROM THESE TWO SYSTEMS...THUS WHILE SHOWERS ARE STILL EXPECTED...HIGHER CONFIDENCE EXISTS IN COVERAGE FARTHER EAST. THIS EVENING THE FIRST MAIN SHORTWAVE WILL BE PASSING NE WHILE THE MAIN SOUTHERN STREAM ENERGY PASSES EAST THROUGH THE OHIO VALLEY...AND THE NORTHERN STREAM SHORTWAVE LAGS BEHIND BACK IN MN/IA. THERE IS ALSO THE LOSS OF DEEPER MOISTURE...THEREFORE EXPECT SHOWERS TO TAPER/END/TURN TO DRIZZLE POSSIBLY OVERNIGHT FOR A TIME. THEN MONDAY MORNING WE GET THE COUPLED UPPER LEVEL FORCING FROM THE NORTHERN STREAM LOW AND SURFACE COLD FRONT WHICH WILL LIKELY BRING ANOTHER ROUND OF SHOWERS MONDAY MORNING. SHOWERS WILL EASE MONDAY AFTERNOON. IT WILL BE QUITE BREEZY/WINDY BEHIND THE FRONT ON MONDAY IN THE COLD ADVECTION REGIME. KMD && .LONG TERM... 340 AM CDT MONDAY NIGHT THROUGH SATURDAY... THE THEME OF THE EXTENDED WILL BE THE UNSEASONABLY COOL WEATHER. A HIGH AMPLITUDE PATTERN WILL BE IN PLACE WITH STRONG UPPER LEVEL RIDGING EXTENDING WELL NORTH INTO THE CANADIAN ROCKIES AND SIMILARLY HIGH AMPLITUDE RIDGING IN THE NORTH ATLANTIC. THAT LEAVES OUR NORTHERN STREAM SHORTWAVE FROM SUNDAY/MONDAY WITH NO WHERE TO GO. THIS WILL KEEP MUCH OF THE EASTERN HALF OF THE COUNTY...INCLUDING OUR REGION...UNDER COOL NORTHWEST FLOW. THIS PATTERN ALSO FAVORED STRONGLY SHEARED OUT AND ELONGATED VORT MAXES TO PIVOT THROUGH BRINGING PERIODS OF SHOWERS. WITH PWAT VALUES QUITE LOW IN THIS AIRMASS...MUCH OF THE PERIOD WILL BE DRY AND EVEN THE SHOWERS SHOULD NOT BE VERY STRONG. BUT MORE IMPORTANTLY...SEASONAL AVERAGE HIGHS/LOWS FOR LATE APRIL ARE THE LOWER 60S (MID 60S SOUTH) AND LOWER 40S RESPECTIVELY...AND MUCH OF THIS PERIOD WILL FEATURE HIGHS IN THE 50S AND LOWS IN THE MID 30S...POSSIBLY COOLER A NIGHT OR TWO IF WINDS ARE LIGHTER. TEMPERATURE ANOMALIES ARE NOT THAT EXTREME THOUGH...SO RECORD COLD IS NOT ANTICIPATED. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * EAST WINDS ARND 6 TO 10 KT...OCCASIONAL GUSTS TO 17KT. * WINDS TURN NORTH LATE TONIGHT...THEN NORTHWEST EARLY MON. * RAIN OVERSPREAD TAF SITES LATE THIS AFTN THRU TONIGHT. * POSSIBLE LOW END MVFR CIGS OR PATCHY IFR CIGS DEVELOPING. BEACHLER //DISCUSSION...UPDATED 06Z... WITH THE DEPARTING HIGH PRESSURE TO THE EAST...MID-LVL MOISTURE WAS SLOWLY LIFTING NORTH ACROSS THE NORTHERN IL/NORTHWEST IN AIRFIELDS. THIS HAS ALLOWED A CIRRUS CLOUD DECK TO THICKEN...AND ADDITIONAL MOISTURE IS EXPECTED TO LIFT NORTHEAST AS A LOW PRESSURE SYSTEM NEARS THE REGION LATER TONIGHT INTO EARLY MON. GUIDANCE HAS BEEN SLOWLY TRENDING LATER WITH THE ARRIVAL OF PRECIP UNTIL AFT 18Z...AND MAY NOT BE CLOSER TO 23Z. WILL CONTINUE TO MENTION VCSH BUT PUSH IT TO 20Z...THEN EXPECT THE COVERAGE TO INCREASE IN PRECIP CLOSER TO 23Z. WITH THE STEADILY THICKEN AND LOWER CLOUDS...THE CHALLENGE IS ALSO ON WIND SPEEDS. IT IS STILL POSSIBLE GUSTS WILL NEED TO BE PUT BACK INTO THE TAF...ALTHOUGH WITH THE ABUNDANT CLOUD COVER...IT IS QUESTIONABLE HOW FREQUENT GUSTS WILL OCCUR AT THE TAF SITES. SO HAVE REMOVED THE MENTION AT THIS TIME AND JUST INCREASED THE SUSTAINED WINDS. THEN AT SOME POINT LATE THIS EVENING CIGS ARE EXPECTED TO QUICKLY DIP TO MVFR AND POSSIBLY TO IFR CONDS. PRECIP COVERAGE WILL BEGIN TO DIMINISH EARLY MON...AND MAY TREND TOWARDS PATCHY DRIZZLE WHICH MAY ALSO FURTHER LOWER CIGS AND VSBYS EARLY MON MORNING. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 09Z... * HIGH CONFIDENCE IN ALL ELEMENTS THROUGH 18Z...MEDIUM CONFIDENCE IN WIND DIR/SPEED AFT 18Z. * MEDIUM CONFIDENCE IN PRECIP TIMING/COVERAGE. * HIGH CONFIDENCE IN CIGS DIMINISHING TO AT LEAST MVFR CONDS AFT 21Z...AND MEDIUM CONFIDENCE IN CIGS BECOMING IFR AFT 3Z MON. BEACHLER //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...CHANCE OF SHRA/MVFR. GUSTY WEST-NORTHWESTERLY WINDS. TUESDAY...SLGT CHANCE PM SHRA...BUT MAINLY VFR. GUSTY WEST WINDS. WEDNESDAY...SLGT CHANCE SHRA. MAINLY VFR. WEST-NORTHWEST WINDS. THURSDAY...VFR. NORTH-NORTHEAST WINDS. FRIDAY...MAINLY VFR. CHC PM SHRA. KJB && .MARINE... 257 AM CDT LOW PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY LIFT NORTHEAST TOWARDS THE LOWER GREAT LAKES REGION TONIGHT/EARLY MON. GUIDANCE CONTINUES TO INDICATE THE GRADIENT WILL TIGHTEN ACROSS THE LAKE...HOWEVER THIS APPEARS TO BE MORE FOCUSED ALONG THE SOUTHERN TIP OF THE LAKE. WITH THE CONTINUED EASTERLY WINDS...IT IS POSSIBLE MARGINAL SMALL CRAFT CONDITIONS MAY DEVELOP FOR THE ILLINOIS SHORELINE LATER TODAY INTO TONIGHT. THE LOW PRESSURE WILL THEN APPROACH THE LAKE AND BRIEFLY WEAKEN THE GRADIENT EARLY MON. THEN AS THE LOW LIFTS NORTHEAST LATER IN THE DAY MON...IT WILL DEEPEN AND MERGE WITH ANOTHER LOW...WHICH WILL CREATE A TIGHT GRADIENT OVER THE LAKE AND INCREASING WEST/NORTHWEST TUE. AFTER TUE THE DOMINANT WIND DIRECTION WILL BE NORTHWEST THROUGH MID- WEEK...BEFORE RELAXING TO THE WEST. THIS WILL ALLOW HIGHER WAVES TO BE FOCUSED IN THE SOUTHERN HALF OF LAKE MICHIGAN THROUGH MID- WEEK. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
344 AM CDT SUN APR 19 2015 .SHORT TERM... 340 AM CDT THROUGH MONDAY... UPPER AIR ANALYSIS EARLY THIS MORNING DEPICTS DEEP UPPER LEVEL LOW PRESSURE NOW PUSHING INTO WESTERN KANSAS. MULTIPLE VORT MAXES ARE ROTATING AROUND THE LOW. THE STRONGEST OF THESE EXIST IN TEXAS AND THROUGH THE CENTRAL PLAINS...WITH SOME SMALLER SCALE WAVES EXTENDING INTO EASTERN MO/FAR WESTERN IL WERE SOME SCATTERED THUNDERSTORMS WERE ONGOING. A NORTHERN STREAM SHORTWAVE IS ENTERING THE NORTHERN PLAINS WITH SOME SHOWERS OUT AHEAD OF IT AS WELL. AT THE SURFACE...THE COLD FRONT THAT PASSED THROUGH NORTHEAST ILLINOIS AND NW INDIANA SATURDAY HAS PUSHED INTO CENTRAL ILLINOIS...BUT HAS LIKELY COMPLETED ITS SOUTHWARD RETREAT AND HAS WASHED OUT OVER THE PAST FEW HOURS. OVER THE LOCAL AREA...MUCH DRIER NE FLOW EXISTS WITH DEWPOINTS IN THE MID TO UPPER 20S IN THE CITY TO NEAR 40 SOUTH...THOUGH DEWPOINTS ARE POOLING ALONG THE FRONT IN THE UPPER 40S JUST SOUTH OF THE LOT CWA. THE SURFACE LOW THAT IS EXPECTED TO DEVELOP FROM THE SOUTHERN STREAM SHORTWAVE IS ALSO TAKING SHAPE OVER THE SOUTHERN STATES WITH A WARM FRONTAL BOUNDARY EXTENDING FROM WESTERN ARKANSAS THROUGH THE LOWER TENNESSEE VALLEY. AN EXPANSION OF LOWER CLOUD TOPS ON IR IMAGERY ALONG AND AHEAD OF THE WARM FRONT IS OCCURRING. LOW LEVEL WARM/MOIST ADVECTION WILL CONTINUE ITS SLOW PROGRESSION NORTHWARD UNDER MODEST SOUTH/SOUTHEAST FLOW. DEEPER MOISTURE/LIFT REALLY HOLD OFF UNTIL THE AFTERNOON PERIOD ACROSS MOST OF THE AREA. A SOMEWHAT COMPLICATED EVOLUTION AS A MAIN SURFACE LOW CENTER IS FORECAST TO STRENGTHEN AS IT LIFTS NORTH THROUGH INDIANA TODAY THEN FURTHER STRENGTHEN TONIGHT INTO MONDAY WHILE SEVERAL ADDITIONAL SURFACE LOWS DEVELOP AND EVENTUALLY MERGE WITH THE MAIN LOW CENTER. THE SURFACE LOW WILL EVENTUALLY BECOME DRIVEN BY A COMBINATION OF THE SW FLOW AHEAD OF THE SOUTHERN STREAM UPPER LOW AND THE NORTHERN STREAM SHORTWAVE. OF NOTE LATER TODAY...EXPECT COVERAGE OF SHOWERS TO INITIALLY BE SLOW GIVEN THE DRIER AIR PLACE...BUT INCREASING ASCENT ALOFT...LOW LEVEL SSE ISENTROPIC ASCENT AHEAD OF THE LOW AND WRAPPING AROUND THE CLOSED CIRCULATION EXTENDING THROUGH 850 AND EVEN 700 MB COMBINED WITH MODEST LOWER LEVEL FGEN SHOULD ALLOW FOR A BLOSSOMING OF SHOWERS ACROSS THE AREA LATER THIS AFTERNOON AND EVENING. THE HIGHEST PWAT AXIS EXPANDS ACROSS INDIANA TODAY BUT SHOULD GET WRAPPED INTO NE ILLINOIS. RAP MOST UNSTABLE CAPE VALUES RELATIVELY LOW BUT DO EXPAND FROM SE TO NW THIS AFTERNOON AND THIS COUPLED WITH THE PUNCH FROM THE DRY SLOT OF THIS SYSTEM MAY ENABLE A FEW T-STORMS AS WELL...SO SOME OF THE SHOWERS WILL HAVE A MODEST KICK TO THEM IN THE MODERATE/HEAVY RAINFALL DEPARTMENT. EXPECT THAT NORTH CENTRAL ILLINOIS MAY BE UNDER A BIT OF SQUEEZE PLAY FROM THESE TWO SYSTEMS...THUS WHILE SHOWERS ARE STILL EXPECTED...HIGHER CONFIDENCE EXISTS IN COVERAGE FARTHER EAST. THIS EVENING THE FIRST MAIN SHORTWAVE WILL BE PASSING NE WHILE THE MAIN SOUTHERN STREAM ENERGY PASSES EAST THROUGH THE OHIO VALLEY...AND THE NORTHERN STREAM SHORTWAVE LAGS BEHIND BACK IN MN/IA. THERE IS ALSO THE LOSS OF DEEPER MOISTURE...THEREFORE EXPECT SHOWERS TO TAPER/END/TURN TO DRIZZLE POSSIBLY OVERNIGHT FOR A TIME. THEN MONDAY MORNING WE GET THE COUPLED UPPER LEVEL FORCING FROM THE NORTHERN STREAM LOW AND SURFACE COLD FRONT WHICH WILL LIKELY BRING ANOTHER ROUND OF SHOWERS MONDAY MORNING. SHOWERS WILL EASE MONDAY AFTERNOON. IT WILL BE QUITE BREEZY/WINDY BEHIND THE FRONT ON MONDAY IN THE COLD ADVECTION REGIME. KMD && .LONG TERM... 340 AM CDT MONDAY NIGHT THROUGH SATURDAY... THE THEME OF THE EXTENDED WILL BE THE UNSEASONABLY COOL WEATHER. A HIGH AMPLITUDE PATTERN WILL BE IN PLACE WITH STRONG UPPER LEVEL RIDGING EXTENDING WELL NORTH INTO THE CANADIAN ROCKIES AND SIMILARLY HIGH AMPLITUDE RIDGING IN THE NORTH ATLANTIC. THAT LEAVES OUR NORTHERN STREAM SHORTWAVE FROM SUNDAY/MONDAY WITH NO WHERE TO GO. THIS WILL KEEP MUCH OF THE EASTERN HALF OF THE COUNTY...INCLUDING OUR REGION...UNDER COOL NORTHWEST FLOW. THIS PATTERN ALSO FAVORED STRONGLY SHEARED OUT AND ELONGATED VORT MAXES TO PIVOT THROUGH BRINGING PERIODS OF SHOWERS. WITH PWAT VALUES QUITE LOW IN THIS AIRMASS...MUCH OF THE PERIOD WILL BE DRY AND EVEN THE SHOWERS SHOULD NOT BE VERY STRONG. BUT MORE IMPORTANTLY...SEASONAL AVERAGE HIGHS/LOWS FOR LATE APRIL ARE THE LOWER 60S (MID 60S SOUTH) AND LOWER 40S RESPECTIVELY...AND MUCH OF THIS PERIOD WILL FEATURE HIGHS IN THE 50S AND LOWS IN THE MID 30S...POSSIBLY COOLER A NIGHT OR TWO IF WINDS ARE LIGHTER. TEMPERATURE ANOMALIES ARE NOT THAT EXTREME THOUGH...SO RECORD COLD IS NOT ANTICIPATED. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * EAST WINDS ARND 6 TO 10 KT...OCCASIONAL GUSTS TO 17KT. * WINDS TURN NORTH LATE TONIGHT...THEN NORTHWEST EARLY MON. * RAIN OVERSPREAD TAF SITES LATE THIS AFTN THRU TONIGHT. * POSSIBLE LOW END MVFR CIGS OR PATCHY IFR CIGS DEVELOPING. BEACHLER //DISCUSSION...UPDATED 06Z... WITH THE DEPARTING HIGH PRESSURE TO THE EAST...MID-LVL MOISTURE WAS SLOWLY LIFTING NORTH ACROSS THE NORTHERN IL/NORTHWEST IN AIRFIELDS. THIS HAS ALLOWED A CIRRUS CLOUD DECK TO THICKEN...AND ADDITIONAL MOISTURE IS EXPECTED TO LIFT NORTHEAST AS A LOW PRESSURE SYSTEM NEARS THE REGION LATER TONIGHT INTO EARLY MON. GUIDANCE HAS BEEN SLOWLY TRENDING LATER WITH THE ARRIVAL OF PRECIP UNTIL AFT 18Z...AND MAY NOT BE CLOSER TO 23Z. WILL CONTINUE TO MENTION VCSH BUT PUSH IT TO 20Z...THEN EXPECT THE COVERAGE TO INCREASE IN PRECIP CLOSER TO 23Z. WITH THE STEADILY THICKEN AND LOWER CLOUDS...THE CHALLENGE IS ALSO ON WIND SPEEDS. IT IS STILL POSSIBLE GUSTS WILL NEED TO BE PUT BACK INTO THE TAF...ALTHOUGH WITH THE ABUNDANT CLOUD COVER...IT IS QUESTIONABLE HOW FREQUENT GUSTS WILL OCCUR AT THE TAF SITES. SO HAVE REMOVED THE MENTION AT THIS TIME AND JUST INCREASED THE SUSTAINED WINDS. THEN AT SOME POINT LATE THIS EVENING CIGS ARE EXPECTED TO QUICKLY DIP TO MVFR AND POSSIBLY TO IFR CONDS. PRECIP COVERAGE WILL BEGIN TO DIMINISH EARLY MON...AND MAY TREND TOWARDS PATCHY DRIZZLE WHICH MAY ALSO FURTHER LOWER CIGS AND VSBYS EARLY MON MORNING. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE IN ALL ELEMENTS THROUGH 18Z...MEDIUM CONFIDENCE IN WIND DIR/SPEED AFT 18Z. * MEDIUM CONFIDENCE IN PRECIP TIMING/COVERAGE. * HIGH CONFIDENCE IN CIGS DIMINISHING TO AT LEAST MVFR CONDS AFT 21Z...AND MEDIUM CONFIDENCE IN CIGS BECOMING IFR AFT 3Z MON. BEACHLER //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...CHANCE OF SHRA/MVFR. GUSTY WEST-NORTHWESTERLY WINDS. TUESDAY...SLGT CHANCE PM SHRA...BUT MAINLY VFR. GUSTY WEST WINDS. WEDNESDAY...SLGT CHANCE SHRA. MAINLY VFR. WEST-NORTHWEST WINDS. THURSDAY...VFR. NORTH-NORTHEAST WINDS. FRIDAY...MAINLY VFR. CHC PM SHRA. KJB && .MARINE... 257 AM CDT LOW PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY LIFT NORTHEAST TOWARDS THE LOWER GREAT LAKES REGION TONIGHT/EARLY MON. GUIDANCE CONTINUES TO INDICATE THE GRADIENT WILL TIGHTEN ACROSS THE LAKE...HOWEVER THIS APPEARS TO BE MORE FOCUSED ALONG THE SOUTHERN TIP OF THE LAKE. WITH THE CONTINUED EASTERLY WINDS...IT IS POSSIBLE MARGINAL SMALL CRAFT CONDITIONS MAY DEVELOP FOR THE ILLINOIS SHORELINE LATER TODAY INTO TONIGHT. THE LOW PRESSURE WILL THEN APPROACH THE LAKE AND BRIEFLY WEAKEN THE GRADIENT EARLY MON. THEN AS THE LOW LIFTS NORTHEAST LATER IN THE DAY MON...IT WILL DEEPEN AND MERGE WITH ANOTHER LOW...WHICH WILL CREATE A TIGHT GRADIENT OVER THE LAKE AND INCREASING WEST/NORTHWEST TUE. AFTER TUE THE DOMINANT WIND DIRECTION WILL BE NORTHWEST THROUGH MID- WEEK...BEFORE RELAXING TO THE WEST. THIS WILL ALLOW HIGHER WAVES TO BE FOCUSED IN THE SOUTHERN HALF OF LAKE MICHIGAN THROUGH MID- WEEK. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
328 AM CDT SUN APR 19 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 328 AM CDT SUN APR 19 2015 LATEST WATER VAPOR IMAGERY CONTINUES TO SHOW CLOSED UPPER LOW OVER EASTERN COLORADO, WITH LEAD SHORT-WAVE ROTATING AROUND THIS FEATURE ACROSS ARKANSAS/LOUISIANA. AS THIS WAVE LIFTS NORTHWARD, PRECIP WILL EVENTUALLY SPREAD INTO CENTRAL ILLINOIS TODAY. 07Z/2AM RADAR MOSAIC SHOWS DRY CONDITIONS ACROSS THE ENTIRE KILX CWA: HOWEVER, SHOWERS ARE BEGINNING TO DEVELOP AND BECOME MORE WIDESPREAD FURTHER SOUTH ACROSS WESTERN KENTUCKY AND FAR SOUTHERN ILLINOIS. BASED ON RADAR TIMING TOOLS AND LATEST HRRR FORECAST, THINK SCATTERED SHOWERS WILL ARRIVE SOUTH OF I-70 OVER THE NEXT COUPLE OF HOURS, THEN WILL SPREAD NORTHWARD TOWARD THE I-74 CORRIDOR BY MIDDAY. HAVE ADJUSTED POPS TO ACCOUNT FOR THE SLOWER ARRIVAL OF PRECIP DURING THE MORNING, THEN HAVE GONE WITH CATEGORICAL POPS ACROSS THE BOARD THIS AFTERNOON. ASIDE FROM SOME SBCAPES OF AROUND 1000J/KG ACROSS THE FAR SE CWA, FORECAST SOUNDINGS REMAIN FAIRLY STABLE TODAY. AS A RESULT, AM EXPECTING MAINLY SHOWERS WITH JUST A FEW EMBEDDED THUNDERSTORMS. DUE TO CLOUD COVER AND PRECIP, HIGH TEMPERATURES WILL BE SEVERAL DEGREES COOLER THAN IN RECENT DAYS, WITH READINGS MAINLY IN THE 60S. WARMEST TEMPS OF AROUND 70 WILL BE FOCUSED ALONG/WEST OF THE ILLINOIS RIVER WHERE PRECIP WILL BE SLOWEST TO ARRIVE. && .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 328 AM CDT SUN APR 19 2015 LEAD SHORT-WAVE WILL LIFT INTO NORTHERN ILLINOIS/INDIANA BY EARLY EVENING, LIKELY LEADING TO A TEMPORARY LULL IN THE SHOWERS. MEANWHILE, THE MAIN UPPER LOW WILL GET A SOLID PUSH EASTWARD AND WILL ARRIVE ACROSS ILLINOIS LATER TONIGHT INTO MONDAY MORNING. SHOWERS AND PERHAPS A THUNDERSTORM WILL ACCOMPANY THIS FEATURE, SO WILL CONTINUE LIKELY POPS TONIGHT THROUGH MONDAY MORNING. ONCE THE 500MB VORT MAX AND THE ASSOCIATED SURFACE COLD FRONT PASS TO THE EAST, RAIN CHANCES WILL COME TO AN END BY MONDAY AFTERNOON. THANKS TO A TIGHT PRESSURE GRADIENT BEHIND THE DEPARTING FRONT, STRONG W/NW WINDS GUSTING TO BETWEEN 25 AND 30 MPH WILL DEVELOP ON MONDAY. THE WINDS WILL SUBSIDE FOR A TIME MONDAY NIGHT, BUT WILL ONCE AGAIN INCREASE MARKEDLY DURING THE DAY TUESDAY. HIGH TEMPERATURES BOTH DAYS WILL REMAIN IN THE LOWER 60S, WHILE OVERNIGHT LOWS DIP INTO THE UPPER 30S AND LOWER 40S. 00Z APR 19 MODELS HAVE COME INTO MUCH BETTER AGREEMENT CONCERNING THE EXTENDED FORECAST, WITH CONSENSUS FEATURING A CHILLY AND LARGELY DRY WEEK AHEAD. BOTH THE GFS AND ECMWF INDICATE A WEAK COLD FRONT WILL PASS THROUGH CENTRAL ILLINOIS TUESDAY NIGHT INTO WEDNESDAY: HOWEVER, THEY DISAGREE ON HOW MUCH PRECIP IT WILL GENERATE. THE GFS IS SLIGHTLY WETTER AND FASTER WITH FROPA, WHILE THE ECMWF IS DRIER AND ABOUT 6 HOURS SLOWER WITH THE FRONT. DUE TO THE STRONG NORTHWESTERLY UPPER FLOW PATTERN IN PLACE ACROSS THE MIDWEST, THINK THE FASTER GFS IS THE WAY TO GO WITH TIMING, BUT THINK THE DRIER ECMWF IS BETTER WITH QPF AS DEEP MOISTURE WILL BE LACKING WITH THIS FEATURE. AS A RESULT, HAVE OPTED TO CARRY LOW CHANCE POPS EVERYWHERE TUESDAY NIGHT, THEN ONLY ACROSS THE SE CWA ON WEDNESDAY. ONCE THE FRONT PASSES, A COOL/CANADIAN AIRMASS WILL SETTLE INTO THE REGION FOR THE MIDDLE AND END OF THE WEEK. HIGH TEMPERATURES WILL STRUGGLE TO REACH THE 60 DEGREE MARK ON BOTH WEDNESDAY AND THURSDAY, WHILE LOWS DROP INTO THE 30S. COLDEST MORNING MAY END UP BEING FRIDAY MORNING, WHEN RIDGE OF HIGH PRESSURE IS OVERHEAD AND WINDS WILL BE LIGHTEST. WILL NEED TO KEEP AN EYE ON TEMPS, AS FROST ADVISORIES WILL BE POSSIBLE ACROSS PARTS OF CENTRAL/SOUTHEAST ILLINOIS LATER THIS WEEK. AFTER THAT, ANOTHER SYSTEM WILL APPROACH FROM THE SOUTHWEST BY THE END OF THE WEEK: HOWEVER, ITS INFLUENCE LIKELY WILL NOT BE FELT UNTIL FRIDAY NIGHT/SATURDAY AT THE EARLIEST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1145 PM CDT SAT APR 18 2015 VFR CONDITIONS CONTINUE ACROSS CENTRAL IL TAF SITES THIS EVENING AS A COMPLEX PATTERN OF A LARGE SCALE CENTRAL U.S. TROUGH WITH MULTIPLE EMBEDDED DISTURBANCES DEVELOPS. MAINLY VFR CONDITIONS EXPECTED UNTIL AROUND 12Z WHEN THE FIRST EMBEDDED DISTURBANCE LIFTS NORTHEASTWARD INTO SE ILLINOIS. EXPECT INCREASING PRECIPITATION AT SOUTHERN TERMINALS KSPI-KDEC AROUND 10Z SPREADING NORTH TO KPIA-KBMI-KCMI AROUND 12Z. BY 14-16Z...PREDOMINANT RAIN WITH MVFR CIGS/VSBYS LIKELY AND INCLUDED IN TAFS. ISOLATED THUNDERSTORMS POSSIBLE AS WELL...BUT LIKELIHOOD/TIMING NOT HIGH ENOUGH FOR EXPLICIT MENTION THIS FAR OUT. BRIEFLY IMPROVING CONDITIONS LATE AFTERNOON EARLY EVENING AS FIRST DISTURBANCE MOVES OUT OF CENTRAL IL...BUT TRAILING WAVE/COLD FRONT EXPECTED TO INITIATE ADDITIONAL SHOWERS/THUNDERSTORMS TOWARD 06Z. WITH A NARROW WINDOW OF UNCERTAIN IMPROVEMENT...KEPT MVFR CIGS/VSBYS THROUGH 06Z. WINDS E-NE5-10 KTS THROUGH 15Z BECOMING VARIABLE- NNW DURING AFTERNOON AS LOW LIFTS TO THE NE OF CENTRAL IL AREA. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BARNES LONG TERM...BARNES AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
733 AM CDT SUN APR 19 2015 .UPDATE... ISSUED AT 730 AM CDT SUN APR 19 2015 SCATTERED SHOWERS CONTINUE TO DEVELOP AND MOVE GENERALLY IN A NORTHWARD DIRECTION...AND WERE MAINLY WEST OF A MACOMB IL TO MANCHESTER IA LINE. THESE SHOWERS WERE OCCURRING IN THE AXIS OF THE BETTER 850 MB MOISTURE TRANSPORT AND PRECIPITABLE WATERS OVER AN INCH. ELSEWHERE...LOW PRESSURE WAS ORGANIZING IN THE LOWER MS VALLEY AND A BROAD AREA OF PRESSURE FALLS WAS NOTED TO THE NORTH INDICATING LARGE SCALE ASCENT/WARM AIR ADVECTION WAS INCREASING. ALSO PRESSURE FALLS WERE OCCURRING IN THE UPPER MS VALLEY IN ASSOCIATION WITH THE DIGGING NORTHERN STREAM TROUGH. REGIONAL DOPPLER RADARS WERE SHOWING THE LEADING EDGE OF A RATHER LARGE AREA OF RAIN/ISOLATED THUNDERSTORMS FROM THE MO OZARKS AND SOUTHERN IL...MOVING NORTHWARD. THE HRRR MESO MODEL HAS CAPTURED THIS RAIN AREA WITH THE LEADING EDGE REACHING MACOMB BY NOON...THE QUAD CITIES BY EARLY AFTERNOON AND DUBUQUE/FREEPORT BY LATE AFTERNOON. THEREFORE...WIDESPREAD RAIN APPEARS LIKELY THIS AFTERNOON AND CONTINUING TONIGHT...WHICH THE CURRENT GRIDS DEPICT. && .SYNOPSIS... ISSUED AT 345 AM CDT SUN APR 19 2015 MODELS CONTINUE TO STRUGGLE WITH THE EASTERLY FEED OF DRY AIR INTO OUR NORTHEAST CWA AND AT SOME LOCATIONS DEWPOINTS WERE 10 DEGREES LOWER THAN ANY GUIDANCE. IN OUR WESTERN CWA GUIDANCE WAS CLOSE TO REALITY AS WINDS WERE MORE SOUTHEAST. SPC MESO ANALYSIS SHOWED DECENT 850 MB MOISTURE TRANSPORT ALONG WITH PRECIPITABLE WATERS OVER AN INCH IN OUR WESTERN CWA. AND SURE ENOUGH DOPPLER RADAR HAS SHOWN POCKETS OF SHOWERS AND ISOLATED THUNDERSTORMS ALL NIGHT. RAINFALL ESTIMATES INDICATE 1/4 TO 3/4 OF AN INCH HAS FALLEN IN SOME SPOTS IN OUR WEST SINCE LAST EVENING. 3 AM TEMPERATURES RANGED FROM 50 AT FREEPORT TO 61 AT MACOMB. ELSEWHERE...CANADIAN HIGH PRESSURE WAS CENTERED NORTHEAST OF LAKE SUPERIOR AND SOME SITES IN NW WI WERE REPORTING DEWPOINTS IN THE TEENS. UPPER LEVEL TROUGH WAS DIGGING INTO THE NORTHERN PLAINS WHILE ANOTHER TROUGH WAS PUSHING INTO THE CENTRAL/SOUTHERN PLAINS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 345 AM CDT SUN APR 19 2015 FORECAST FOCUS ON INCREASING RAIN AND TEMPERATURES. TODAY...UPPER LEVEL TROUGH APPROACHES FROM THE WEST AND THIS WILL PROVIDE LARGE SCALE ASCENT ALONG WITH BETTER MOISTURE TRANSPORT AS THE DAY PROGRESSES. THE MORE WIDESPREAD RAIN APPEARS TO DEVELOP THIS AFTERNOON WITH THE ARRIVAL OF STRONGER FORCING...AS A SHORT WAVE PUSHES ACROSS IA AHEAD OF THE MAIN TROUGH. MEANWHILE...PHASING BEGINS TO OCCUR AND MODELS LIFT A DEEPENING CYCLONE OUT OF THE LOWER MS VALLEY INTO FAR WESTERN INDIANA BY 00Z. INTERESTING THAT THE NAM/ECMWF KEEP NW IL DRY MUCH OF THE DAY AND THEY MAY BE ON TO SOMETHING WITH SUCH A DRY EASTERLY FEED INTO THAT AREA. I WILL MENTION ISOLATED THUNDERSTORMS THIS AFTERNOON AS DEEP LAYER SHEAR IS WEAK AND MUCAPE IS 500 J/KG OR LESS. WITH MORE CLOUDINESS TODAY MAXIMUM TEMPERATURES SHOULD BE COOLER THAN THAN THE PAST COUPLE OF DAYS. I AM EXPECTING HIGHS IN THE UPPER 60S TO LOWER 70S AT MOST LOCATIONS. TONIGHT...PHASING IS NEARLY COMPLETE AND A LONG WAVE TROUGH PUSHES ACROSS THE MIDWEST WITH DECENT FORCING AND GOOD MOISTURE IN PLACE. IN THE MEANTIME...THE SLOWLY DEEPENING CYCLONE LIFTS INTO NORTHERN LOWER MI BY 12Z. MODELS INDICATE WIDESPREAD RAIN OVER THE CWA MUCH OF THE NIGHT. THIS LOOKS TO BE MORE OF A STRATIFORM/DEFORMATION TYPE RAIN RATHER THAN ALL OUT CONVECTIVE/MCS TYPE SO WILL NOT MENTION THUNDER AS INSTABILITY IS VERY LIMITED...AND THE ENTIRE COLUMN IS VERY SATURATED. A COLD FRONT WILL PUSH ACROSS THE CWA DURING THE NIGHT USHERING MUCH COOLER TEMPERATURES INTO THE AREA BY MORNING. MINIMUM TEMPERATURES WILL RANGE FROM THE LOWER 40S AT INDEPENDENCE TO THE UPPER 40S AT PRINCETON AND MACOMB IN ILLINOIS. RAINFALL AMOUNTS TODAY THROUGH TONIGHT SHOULD BE 0.3 TO 0.7 INCHES OVER MUCH OF THE CWA. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 345 AM CDT SUN APR 19 2015 COOLER AND MAINLY DRY FOR MUCH OF UPCOMING WEEK WITH FROST/FREEZE POTENTIAL LATER IN THE WEEK. MUCH OF THE UPCOMING WEEK AHEAD WILL FEATURE A LARGE AND SLOW MOVING UPPER LOW FROM THE GREAT LAKES TO EASTERN CANADA DUE TO HIGHLY AMPLIFIED RIDGING OVER THE EASTERN ATLANTIC AND GREENLAND. OUR CWA WILL BE GOVERNED BY NORTHWEST FLOW ON BACKSIDE OF THE LARGE UPPER LOW WHICH WILL USHER IN REINFORCING BOUTS OF CANADIAN AIR RESULTING IN COOLER HIGHS IN THE 50S AND 60S... WITH LOWS MAINLY IN THE 30S. THE COOLER AIR WILL ALSO BE ACCOMPANIED BY WINDY CONDITIONS MONDAY AND TUESDAY WITH THE POTENTIAL TO BE NEAR WIND ADVISORY CRITERIA GIVEN JUXTAPOSITION OF TIGHT PRESSURE GRADIENT... COLD ADVECTION AND DEEP MIXING. AFTER SOME LINGERING SHOWERS POSSIBLE EARLY MONDAY AM... WILL HAVE THE POTENTIAL FOR AFTERNOON POPCORN SHOWERS ACROSS MAINLY THE NORTHERN CWA BOTH MONDAY AND TUESDAY WITH STEEP MID LEVEL LAPSE RATES... COLD AIR ALOFT... AND SKINNY CAPE NOTED ON FORECAST SOUNDINGS. WILL NEED TO WATCH FOR ENHANCED WIND GUSTS WITH ANY SHOWERS VIA EVAPORATIVE COOLING OF PCPN IN LARGE... DRY SUB-CLOUD LAYER WITH CLASSIC INVERTED V SOUNDINGS. CANADIAN SURFACE RIDGE AXIS BUILDING IN THURSDAY INTO FRIDAY WILL BRING POTENTIAL FOR FROST AND POSSIBLY FREEZING TEMPS ONE OR BOTH MORNINGS. MIN TEMPS MAY NEED LOWERING BY 3-5 DEGS SOME LOCATIONS ESPECIALLY THURSDAY AM BASED ON 850 MB TEMPS -4C TO -7C WITH MORE WIDESPREAD 20S POSSIBLE WITH ANY DURATION OF CLEAR SKIES AND LIGHT WINDS. RAIN CHANCES LOOK TO RETURN BY EITHER LATE IN THE WEEK AND/OR NEXT WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 730 AM CDT SUN APR 19 2015 VFR CONDS BECOMING MVFR/LCL IFR CONDS. SCATTERED SHOWERS IN EASTERN IA THIS MORNING WILL EXPAND IN COVERAGE AND THE RAIN WILL BE WIDESPREAD THIS AFTERNOON AND TONIGHT. ISOLATED THUNDERSTORMS ARE ALSO POSSIBLE...MAINLY THIS AFTERNOON. A COLD FRONT WILL ALSO ARRIVE TONIGHT. EAST TO SOUTHEAST WINDS LESS THAN 10 KNOTS TODAY THEN BECOMING NORTHWEST 15 TO 25 KNOTS BEHIND THE COLD FRONT TONIGHT. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...HAASE SYNOPSIS...HAASE SHORT TERM...HAASE LONG TERM...MCCLURE AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1205 AM CDT SUN APR 19 2015 .DISCUSSION... FOR THE 06Z TAF PACKAGE. && .AVIATION... AS ANTICIPATED...VISIBILITY RESTRICTIONS HAVE BEGUN TO DEVELOP ACROSS THE AREA...AND CONVECTIVE COMPLEX APPROACHING FROM THE NORTHWEST IS STARTING TO DECAY. TIMED THE REMNANTS OF THIS FEATURE INTO KBPT...KLCH...AND KAEX AS JUST A BRIEF PERIOD OF INCREASED WINDS AND LIGHT RAIN. NO EFFECTS CARRIED AT THE ACADIANA TERMINALS. EXPECT THAT THE RESULTANT MIXING WILL IMPROVE THE VISIBILITY...AT LEAST TEMPORARILY...BUT DID SHOW THE FOG RE- DEVELOPING A COUPLE HOURS LATER. VFR TO PREVAIL TOMORROW ONCE THE FOG ERODES. 13 && .PREV DISCUSSION... /ISSUED 925 PM CDT SAT APR 18 2015/ DISCUSSION... MAIN WX CONCERN IS THE MCS OVER C AND N TX...MOVING E. RADAR STILL SHOWS FAIRLY SOLID SQUALL LINE BETWEEN WHILE SOME WEAKENING IS EXPECTED TO CONTINUE...LATEST NAM12 & HRRR SUGGEST IT CONTINUING E THE NEXT SEVERAL HOURS...AFFECTING INLAND SE TX/C LA BETWEEN 06-09Z. THUS...HAVE INCREASED THE POPS AND QPF ACROSS THESE AREAS FOR THE EVENING UPDATE. FOR THE REMAINDER OF THE AREA...20% CONTINUES FOR ANY ISO SHRA/TSRA AHEAD OF THIS SYSTEM. DML PREV DISCUSSION... /ISSUED 734 PM CDT SAT APR 18 2015/ DISCUSSION... FOR THE 00Z TAF PACKAGE. AVIATION... MAINLY ISOLATED TO SCATTERED SHOWERS ACROSS PARTS OF EAST AND SOUTH CENTRAL LOUISIANA EARLY THIS EVENING. LATEST HRRR DEPICTS CONVECTIVE COMPLEX OVER CENTRAL TEXAS REACHING PERHAPS AS FAR AS JUST EAST OF THE SABINE RIVER SOMETIME AFTER MIDNIGHT BEFORE DISSIPATING. WILL CONTINUE TO MONITOR RADAR/MODEL TRENDS THROUGH THE EVENING. OTHERWISE...A MIX OF MVFR/VFR CIGS ACROSS THE AREA IS EXPECTED TO LOWER INTO MVFR/IFR AS LIGHT FOG AND/OR LOWER CIGS DEVELOP DURING THE OVERNIGHT HOURS. IMPROVEMENT TO VFR IS EXPECTED ON SUNDAY AS DRIER AIR MOVES IN FROM THE WEST. 13 PREV DISCUSSION... /ISSUED 421 PM CDT SAT APR 18 2015/ SYNOPSIS... LATEST UA ANALYSIS AND WV IMAGERY SHOWS SLOW-MOVING UPR LOW OVER ERN COLORADO...WITH MOIST SWLY FLOW CONTINUING TO STREAM OVER THE REGION. ONE IMPULSE ASSOCIATED WITH THIS SYSTEM WAS MOVING ACRS SRN TX INTO THE WRN GULF...WITH A SECOND IMPULSE CROSSING WRN TX. THESE TWO SYSTEMS WERE TRIGGERING STORMS ACRS THE NW/CNTL GULF COAST AS WELL AS ACRS WRN TX. OVER THE IMMEDIATE CWA...ACTIVITY HAS REMAINED FAIRLY SCTD...WITH A SWATH OF LT/MODT RAIN OVER THE COASTAL WATERS...AND SCT SHRA/TSRA ACRS CNTL/WRN LA. DISCUSSION... OVERNIGHT CONVECTIVE COMPLEX ALLOWED THE AIRMASS TO STABILIZE TODAY...AND ONGOING CONVECTION OVER THE GULF HAS LIMITED INFLOW. THIS COMBINATION HAS REDUCED THE POTENTIAL FOR HEAVY RAIN AND WIDESPREAD ACTIVITY TODAY AND LIKELY INTO TONIGHT. LOOKING AT A COMBINATION OF RECENT HRRR RUNS AS WELL AS RAP/NAM GUIDANCE SHOWS A DECREASING TREND DURING THE EVENING AND OVERNIGHT. ACTIVITY ALONG THE TX COAST IS EXPECTED TO TREK E/NE BUT GRADUALLY WEAKEN AS IT APPROACHES OUR COASTAL WATERS ZONES. LIKEWISE...THE STORMS ACRS WRN TX WILL MOVE EAST THIS EVENING...BUT ALSO WEAKEN AS THEY REACH THE AREA LATER TONIGHT. QPF VALUES ARE EXPECTED TO REMAIN BELOW AN INCH THROUGH SUNDAY...AND WITH THIS IN MIND...HAVE GONE AHEAD AND CANCELLED THE FLASH FLOOD WATCH. DRIER MID LVL AIR WILL BEGIN TO PUSH EAST OVER THE AREA ON SUNDAY...HELPING TO BRING A REPREIVE FROM THE RAINY PATTERN. HOWEVER...ENOUGH MOISTURE WILL LINGER TO ALLOW FOR AT LEAST A SLT CHC FOR A FEW SHOWERS OR TSTMS. BY SUNDAY NIGHT...A COOL FRONT WILL MOVE THROUGH THE REGION. ENOUGH CONVERGENCE AND LIFT ARE EXPECTED ALONG THE FRONTAL BOUNDARY TO PRODUCE A SCT BAND OF SHOWERS AND TSTMS AS IT CROSSES THE AREA. SPC DOES HAVE THE AREA OUTLINED IN A SLT RISK FOR SUNDAY/SUNDAY NIGHT AS INSTABILITY LOOKS TO INCREASE AHEAD OF THE BOUNDARY. THUS AN ISOLATED STRONG TO SEVERE STORM CANNOT BE RULED OUT ESPECIALLY ACRS THE NRN TIER OF COUNTIES AND PARISHES. DRY WEATHER FINALLY RETURNS ON MONDAY AND SHOULD CONTINUE INTO TUESDAY AS HIGH PRES BUILDS INTO THE AREA. SMALL RAIN CHCS WILL RETURN BY MIDWEEK WITH CHCS INCREASING TOWARD THE LATTER PART OF THE WEEK. ZONAL FLOW WILL PREVAIL THROUGH THE WEEK AND LIFT ASSOCIATED WITH EMBEDDED DISTURBANCES WILL KEEP AT LEAST CHC POPS OVER THE AREA THURSDAY AND FRIDAY. MARINE... LT TO MDT SWLY FLOW WILL CONTINUE THROUGH SUNDAY WITH SHOWERS AND TSTMS GRADUALLY DIMINISHING. A COOL FRONT WILL CROSS THE COASTAL WATERS LATE SUNDAY NIGHT...WITH MODT OFFSHORE FLOW DEVELOPING FOR MONDAY. EXERCISE CAUTION CONDITIONS COULD BE POSSIBLE AT TIMES MONDAY INTO TUESDAY. WINDS WILL GRADUALLY VEER ELY TUESDAY...THEN SELY BY WEDNESDAY AS SFC HIGH PRES MOVES EAST. && .PRELIMINARY POINT TEMPS/POPS... AEX 63 83 60 76 / 30 30 30 10 LCH 64 82 63 79 / 20 20 20 10 LFT 65 84 64 79 / 30 20 20 10 BPT 64 82 63 79 / 20 20 20 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS GRAY ME
1033 PM EDT MON APR 20 2015 .SYNOPSIS... LOW PRESSURE MEANDERING NORTH OF THE GREAT LAKES WILL DRIVE A COLD FRONT TOWARD THE REGION TONIGHT. THE FRONT WILL SLOWLY CROSS THE REGION ON TUESDAY. LOW PRESSURE NORTH OF THE GREAT LAKES WILL GRADUALLY WEAKEN AS IT DRIFTS SOUTHEAST INTO NEW ENGLAND WEDNESDAY THROUGH THURSDAY. LOW PRESSURE WILL CONTINUE TO WEAKEN AS IT MEANDERS NORTH OF NEW ENGLAND FRIDAY THROUGH SATURDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... UPDATE...THE HIGHEST THREAT FOR STRONG WIND GUSTS IS COMING TO AN END...SO WILL TAKE DOWN THE WIND ADVISORY. OTHERWISE NO MAJOR CHANGES TO THE FORECAST. MESOSCALE MODELS STILL FAVOR THE IDEA OF A COMPLEX OF TSTMS CROSSING THE FORECAST AREA DURING THE MORNING. SO NO CHANGES THERE EITHER. HAVE MODIFIED THE GRIDS THRU MORNING BASED ON LATEST HI-RES MODEL GUIDANCE. EXAMINING RECENT HRRR RUNS HAVE A LARGE AREA FAVORABLE FOR LIGHTNING DEVELOPMENT MOVING ACROSS THE REGION ON THE LEADING EDGE OF THE DRY SLOT NEAR MORNING. IN ADDITION...THE SPC SSEO PRODUCTS ALSO FAVOR A CLUSTER OR LINE OF TSTMS CROSSING THE FORECAST AREA NEAR 12Z. HAVE INCREASED THE PROBABILITY FOR THUNDER LATE TONIGHT AND EARLY TUE AS A RESULT. HAVE ALSO INTRODUCED SOME AREAS OF HEAVY RA TO THE GRIDS NEAR THE COASTAL FRONT AS WELL AS IN THE EAST SLOPES OF THE MTNS WHERE STRONG SELY LLJ WILL IMPINGE UPON THE TERRAIN. THIS LLJ...WHICH IS REALLY JUST GETTING UNDERWAY OVER SRN NEW ENGLAND PER KBOX 88D...WILL SLOWLY TRAVERSE THE COAST THRU ABOUT 06Z. THIS PUTS HEAVIEST PRECIP IN THE FORECAST AREA BETWEEN ABOUT 00Z AND 06Z. IN ADDITION TO THE HEAVY PRECIP...THIS LLJ MAY INDUCE SOME STRONG DOWNSLOPE WIND GUSTS NW OF THE WHITE MTNS. PREVIOUS DISCUSSION...THE FIRST BATCH OF RAIN FROM THIS MORNING WAS MOVING INTO EASTERN MAINE AS A WARM FRONT LIFTED NORTH INTO SOUTHERN CANADA. SO FAR ONLY A TENTH TO ABOUT A THIRD OF AN INCH OF RAIN HAS FALLEN TODAY WITH SOME ISOLATED HIGHER AMOUNTS. THIS MORNINGS GYX SOUNDING HAD PLENTY OF DRY AIR AND THIS INHIBITED RAINFALL FROM SPREADING FASTER FOR THE FIRST HALF OF THE DAY. STEADIER RAINS ARE NOW OVER SOUTHERN NH AND MOVING INTO WESTERN MAINE. THIS TREND WILL CONTINUE INTO THE EVENING HOURS. A SECONDARY CYCLONE WILL FORM TONIGHT OVER THE VIRGINIAS AND MOVE NE ALONG THE ATLANTIC COAST. AS IT DEEPENS IN THE GULF OF MAINE A LLJ WILL STRENGTHEN AND FEED MOISTURE RICH AIR INTO COASTAL NH AND MAINE. WARM RAIN PROCESSES AND TRAINING OF CELLS WILL SUPPORT HEAVY RAIN OVERNIGHT AND INTO TUESDAY. A FLOOD WATCH REMAINS IN EFFECT AS RAIN COMBINES WITH SNOWMELT TO BRING RIVERS AND STREAMS TO NEAR BANKFULL. WINDS WILL BE GUSTY... ESPECIALLY ALONG THE COAST... BUT WE SHOULD FALL SHORT OF WIND ADVISORY CRITERIA. COASTAL FLOODING WILL ALSO BE A CONCERN FROM PORTLAND WESTWARD AS EASTERLY FLOW INCREASES AND COINCIDES WITH THE ASTRONOMICAL HIGH TIDE. MORE INFORMATION ON THESE HAZARDS BELOW. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... MODERATE TO HEAVY RAIN CONTINUES INTO TUESDAY MORNING. MUCAPE VALUES INDICATE A SLIGHT CHANCE FOR THUNDERSTORMS BETWEEN 12-18Z TOMORROW AS THE COLD CORE OF THE UPPER LOW SWINGS BY OVERHEAD. DRIER AIR PUNCHES IN FROM THE SW MIDDAY TUESDAY. SOME LINGERING SHOWERS WILL BE POSSIBLE OVER THE MOUNTAINS IN UPSLOPE FLOW. HIGHS SHOULD WARM INTO THE UPPER 40S NORTH TO LOWER 60S SOUTH. ADDITIONAL SHOWERS WILL BE POSSIBLE TUESDAY NIGHT WITH CYCLONIC FLOW ALOFT. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... BROAD UPPER LEVEL CLOSED LOW WILL KEEP WEATHER UNSETTLED IN THE NORTHEAST THROUGH THE WEEK AND INTO THE WEEKEND AS IT GRADUALLY SHIFTS EAST. EXPECT SEVERAL LOBES OF ENERGY TO ROTATE AROUND THIS SYSTEM AND INTO THE NORTHEAST. ANY MORNING SUN ON WEDNESDAY WILL QUICKLY GIVE WAY TO CLOUDS AND SHOWERS AS THE FIRST OF THESE DISTURBANCES SWINGS INTO THE REGION. EXPECT THESE SHOWERS TO PERSIST INTO WEDNESDAY NIGHT AS A WEAK SURFACE LOW SLOWLY CROSSES THE REGION. STEADIER PRECIP WILL COME TO AN END AS LOW PRESSURE LIFTS INTO THE MARITIMES ON THURSDAY. EXPECT CLOUDY SKIES AND SCATTERED SHOWERS THURSDAY THROUGH FRIDAY WITH HIGHS IN THE 40S TO LOWER 50S. SHOWER ACTIVITY WILL DIMINISH OVER THE WEEKEND BUT SKIES WILL REMAIN MOSTLY CLOUDY WITH RAIN OR SNOW SHOWERS POSSIBLE MAINLY IN NORTHERN ZONES. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... SHORT TERM...MVFR WILL DETERIORATE TO LIFR AND IFR SHORTLY AS HEAVIER RAIN MOVES IN. RAIN MAY BE LIGHTER AT KHIE WHERE WE WILL SEE THE RAIN SHADOW EFFECT. ALSO SOME SNOW MAY MIX IN LATE IN THE NORTH. EAST WINDS MAY GUST TO 35 KTS AT TIMES. SOME IMPROVEMENT BY MID MORNING TUESDAY AS RAIN MOVES EAST. LONG TERM...AREAS OF MVFR CEILINGS WEDNESDAY THROUGH FRIDAY. && .MARINE... SHORT TERM...EASTERLY WINDS AND SEAS CONTINUE TO BUILD TONIGHT. A GALE WARNING REMAINS IN EFFECT THROUGH 2 PM TUESDAY. WINDS WILL DECREASE BUT A SCA WILL LIKELY BE NEEDED FOR WAVES THROUGH WEDNESDAY EVENING. LONG TERM...SCA`S MAY BE NEEDED THURSDAY AND FRIDAY. && .FIRE WEATHER... ONSHORE FLOW TODAY BRINGS MORE MOISTURE AND EVENTUALLY RAIN TO THE AREA. A SOAKING RAIN IS EXPECTED LATE TODAY AND TUESDAY. && .HYDROLOGY... A WIDESPREAD 1 TO 2 INCHES OF RAIN IS EXPECTED FROM THIS AFTERNOON THROUGH TUESDAY. HOWEVER...GIVEN STRONG MOISTURE INFLOW...LOCALIZED AMOUNTS OF UP TO 3 INCHES COULD OCCUR. THIS WOULD LEAD TO FLOODING PROBLEMS...ESPECIALLY IN AREAS WHERE SNOW MELT IS STILL OCCURRING. A FLOOD WATCH REMAINS IN EFFECT. && .TIDES/COASTAL FLOODING... AS EASTERLY WINDS CONTINUE TO INCREASE...SEAS WILL BUILD 10 TO 15 FT. HIGH TIDE ON APRIL 21 IS AT 1:21 AM WITH A PREDICTED HEIGHT OF 11.4 FT MLLW. HOWEVER...ONSHORE WINDS ARE EXPECTED TO RESULT IN A 1- 2 FT STORM SURGE. THE COMBINATION OF WIND, WAVES AND HIGH TIDE WILL RESULT IN OVERWASH AND POSSIBLE INUNDATION FOR THE BEACHES OF THE SOUTH COAST OF MAINE AND NEW HAMPSHIRE. FARTHER DOWNEAST THE EASTERLY WIND DIRECTION IS LESS FAVORABLE FOR ONSHORE INUNDATION. EVEN SO THE SIGNIFICANT WAVES MAY RESULT IN SOME COASTAL FLOODING AND A COASTAL FLOOD ADVISORY HAS BEEN POSTED THERE. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR MEZ007>009-012>014- 018>028. COASTAL FLOOD ADVISORY UNTIL 3 AM EDT TUESDAY FOR MEZ025>028. COASTAL FLOOD WARNING UNTIL 3 AM EDT TUESDAY FOR MEZ023-024. NH...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR NHZ002>015. COASTAL FLOOD WARNING UNTIL 3 AM EDT TUESDAY FOR NHZ014. MARINE...GALE WARNING UNTIL 2 PM EDT TUESDAY FOR ANZ150>154. && $$ NEAR TERM...LEGRO
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
717 PM EDT MON APR 20 2015 .SYNOPSIS... LOW PRESSURE MEANDERING NORTH OF THE GREAT LAKES WILL DRIVE A COLD FRONT TOWARD THE REGION TONIGHT. THE FRONT WILL SLOWLY CROSS THE REGION ON TUESDAY. LOW PRESSURE NORTH OF THE GREAT LAKES WILL GRADUALLY WEAKEN AS IT DRIFTS SOUTHEAST INTO NEW ENGLAND WEDNESDAY THROUGH THURSDAY. LOW PRESSURE WILL CONTINUE TO WEAKEN AS IT MEANDERS NORTH OF NEW ENGLAND FRIDAY THROUGH SATURDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... UPDATE...WITH LLJ EXPECTED TO PEAK IN INTENSITY OVER THE NEXT FEW HOURS AND WIND GUSTING 40 PLUS MPH ALREADY...I HAVE ISSUED A WIND ADVISORY FOR COOS AND NRN GRAFTON COUNTIES. THE STRONG DOWNSLOPE WIND GUSTS SHOULD BE CONFINED TO THE IMMEDIATE NW SLOPES OF THE HIGH TERRAIN. AFTER MIDNIGHT WINDS WILL DIMINISH AS LLJ LIFTS NEWD. HAVE MODIFIED THE GRIDS THRU MORNING BASED ON LATEST HI-RES MODEL GUIDANCE. EXAMINING RECENT HRRR RUNS HAVE A LARGE AREA FAVORABLE FOR LIGHTNING DEVELOPMENT MOVING ACROSS THE REGION ON THE LEADING EDGE OF THE DRY SLOT NEAR MORNING. IN ADDITION...THE SPC SSEO PRODUCTS ALSO FAVOR A CLUSTER OR LINE OF TSTMS CROSSING THE FORECAST AREA NEAR 12Z. HAVE INCREASED THE PROBABILITY FOR THUNDER LATE TONIGHT AND EARLY TUE AS A RESULT. HAVE ALSO INTRODUCED SOME AREAS OF HEAVY RA TO THE GRIDS NEAR THE COASTAL FRONT AS WELL AS IN THE EAST SLOPES OF THE MTNS WHERE STRONG SELY LLJ WILL IMPINGE UPON THE TERRAIN. THIS LLJ...WHICH IS REALLY JUST GETTING UNDERWAY OVER SRN NEW ENGLAND PER KBOX 88D...WILL SLOWLY TRAVERSE THE COAST THRU ABOUT 06Z. THIS PUTS HEAVIEST PRECIP IN THE FORECAST AREA BETWEEN ABOUT 00Z AND 06Z. IN ADDITION TO THE HEAVY PRECIP...THIS LLJ MAY INDUCE SOME STRONG DOWNSLOPE WIND GUSTS NW OF THE WHITE MTNS. PREVIOUS DISCUSSION...THE FIRST BATCH OF RAIN FROM THIS MORNING WAS MOVING INTO EASTERN MAINE AS A WARM FRONT LIFTED NORTH INTO SOUTHERN CANADA. SO FAR ONLY A TENTH TO ABOUT A THIRD OF AN INCH OF RAIN HAS FALLEN TODAY WITH SOME ISOLATED HIGHER AMOUNTS. THIS MORNINGS GYX SOUNDING HAD PLENTY OF DRY AIR AND THIS INHIBITED RAINFALL FROM SPREADING FASTER FOR THE FIRST HALF OF THE DAY. STEADIER RAINS ARE NOW OVER SOUTHERN NH AND MOVING INTO WESTERN MAINE. THIS TREND WILL CONTINUE INTO THE EVENING HOURS. A SECONDARY CYCLONE WILL FORM TONIGHT OVER THE VIRGINIAS AND MOVE NE ALONG THE ATLANTIC COAST. AS IT DEEPENS IN THE GULF OF MAINE A LLJ WILL STRENGTHEN AND FEED MOISTURE RICH AIR INTO COASTAL NH AND MAINE. WARM RAIN PROCESSES AND TRAINING OF CELLS WILL SUPPORT HEAVY RAIN OVERNIGHT AND INTO TUESDAY. A FLOOD WATCH REMAINS IN EFFECT AS RAIN COMBINES WITH SNOWMELT TO BRING RIVERS AND STREAMS TO NEAR BANKFULL. WINDS WILL BE GUSTY... ESPECIALLY ALONG THE COAST... BUT WE SHOULD FALL SHORT OF WIND ADVISORY CRITERIA. COASTAL FLOODING WILL ALSO BE A CONCERN FROM PORTLAND WESTWARD AS EASTERLY FLOW INCREASES AND COINCIDES WITH THE ASTRONOMICAL HIGH TIDE. MORE INFORMATION ON THESE HAZARDS BELOW. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... MODERATE TO HEAVY RAIN CONTINUES INTO TUESDAY MORNING. MUCAPE VALUES INDICATE A SLIGHT CHANCE FOR THUNDERSTORMS BETWEEN 12-18Z TOMORROW AS THE COLD CORE OF THE UPPER LOW SWINGS BY OVERHEAD. DRIER AIR PUNCHES IN FROM THE SW MIDDAY TUESDAY. SOME LINGERING SHOWERS WILL BE POSSIBLE OVER THE MOUNTAINS IN UPSLOPE FLOW. HIGHS SHOULD WARM INTO THE UPPER 40S NORTH TO LOWER 60S SOUTH. ADDITIONAL SHOWERS WILL BE POSSIBLE TUESDAY NIGHT WITH CYCLONIC FLOW ALOFT. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... BROAD UPPER LEVEL CLOSED LOW WILL KEEP WEATHER UNSETTLED IN THE NORTHEAST THROUGH THE WEEK AND INTO THE WEEKEND AS IT GRADUALLY SHIFTS EAST. EXPECT SEVERAL LOBES OF ENERGY TO ROTATE AROUND THIS SYSTEM AND INTO THE NORTHEAST. ANY MORNING SUN ON WEDNESDAY WILL QUICKLY GIVE WAY TO CLOUDS AND SHOWERS AS THE FIRST OF THESE DISTURBANCES SWINGS INTO THE REGION. EXPECT THESE SHOWERS TO PERSIST INTO WEDNESDAY NIGHT AS A WEAK SURFACE LOW SLOWLY CROSSES THE REGION. STEADIER PRECIP WILL COME TO AN END AS LOW PRESSURE LIFTS INTO THE MARITIMES ON THURSDAY. EXPECT CLOUDY SKIES AND SCATTERED SHOWERS THURSDAY THROUGH FRIDAY WITH HIGHS IN THE 40S TO LOWER 50S. SHOWER ACTIVITY WILL DIMINISH OVER THE WEEKEND BUT SKIES WILL REMAIN MOSTLY CLOUDY WITH RAIN OR SNOW SHOWERS POSSIBLE MAINLY IN NORTHERN ZONES. && .AVIATION /23Z MONDAY THROUGH SATURDAY/... SHORT TERM...MVFR WILL DETERIORATE TO LIFR AND IFR SHORTLY AS HEAVIER RAIN MOVES IN. RAIN MAY BE LIGHTER AT KHIE WHERE WE WILL SEE THE RAIN SHADOW EFFECT. ALSO SOME SNOW MAY MIX IN LATE IN THE NORTH. EAST WINDS MAY GUST TO 35 KTS AT TIMES. SOME IMPROVEMENT BY MID MORNING TUESDAY AS RAIN MOVES EAST. LONG TERM...AREAS OF MVFR CEILINGS WEDNESDAY THROUGH FRIDAY. && .MARINE... SHORT TERM...EASTERLY WINDS AND SEAS CONTINUE TO BUILD TONIGHT. A GALE WARNING REMAINS IN EFFECT THROUGH 2 PM TUESDAY. WINDS WILL DECREASE BUT A SCA WILL LIKELY BE NEEDED FOR WAVES THROUGH WEDNESDAY EVENING. LONG TERM...SCA`S MAY BE NEEDED THURSDAY AND FRIDAY. && .FIRE WEATHER... ONSHORE FLOW TODAY BRINGS MORE MOISTURE AND EVENTUALLY RAIN TO THE AREA. A SOAKING RAIN IS EXPECTED LATE TODAY AND TUESDAY. && .HYDROLOGY... A WIDESPREAD 1 TO 2 INCHES OF RAIN IS EXPECTED FROM THIS AFTERNOON THROUGH TUESDAY. HOWEVER...GIVEN STRONG MOISTURE INFLOW...LOCALIZED AMOUNTS OF UP TO 3 INCHES COULD OCCUR. THIS WOULD LEAD TO FLOODING PROBLEMS...ESPECIALLY IN AREAS WHERE SNOW MELT IS STILL OCCURRING. A FLOOD WATCH REMAINS IN EFFECT. && .TIDES/COASTAL FLOODING... AS EASTERLY WINDS CONTINUE TO INCREASE...SEAS WILL BUILD 10 TO 15 FT. HIGH TIDE ON APRIL 21 IS AT 1:21 AM WITH A PREDICTED HEIGHT OF 11.4 FT MLLW. HOWEVER...ONSHORE WINDS ARE EXPECTED TO RESULT IN A 1- 2 FT STORM SURGE. THE COMBINATION OF WIND, WAVES AND HIGH TIDE WILL RESULT IN OVERWASH AND POSSIBLE INUNDATION FOR THE BEACHES OF THE SOUTH COAST OF MAINE AND NEW HAMPSHIRE. FARTHER DOWNEAST THE EASTERLY WIND DIRECTION IS LESS FAVORABLE FOR ONSHORE INUNDATION. EVEN SO THE SIGNIFICANT WAVES MAY RESULT IN SOME COASTAL FLOODING AND A COASTAL FLOOD ADVISORY HAS BEEN POSTED THERE. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR MEZ007>009-012>014- 018>028. COASTAL FLOOD ADVISORY FROM 11 PM THIS EVENING TO 3 AM EDT TUESDAY FOR MEZ025>028. COASTAL FLOOD WARNING FROM 11 PM THIS EVENING TO 3 AM EDT TUESDAY FOR MEZ023-024. NH...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR NHZ002>015. WIND ADVISORY UNTIL 1 AM EDT TUESDAY FOR NHZ001>003. COASTAL FLOOD WARNING FROM 11 PM THIS EVENING TO 3 AM EDT TUESDAY FOR NHZ014. MARINE...GALE WARNING UNTIL 2 PM EDT TUESDAY FOR ANZ150>154. && $$ NEAR TERM...LEGRO
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
248 PM EDT SUN APR 19 2015 .SYNOPSIS... SHOWERS WILL OVERSPREAD THE REGION THIS EVENING AND CONTINUE THROUGH MONDAY. UNSEASONABLY COOL TEMPERATURES ARE EXPECTED FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH MONDAY/... DRY AIR SAMPLED BY THE 12Z UPPER AIR SOUNDING REVEALS A SUBSTANTIAL LAYER OF DRY AIR. THIS HAS KEPT THE RAIN AND CLOUDS AT BAY FOR MUCH OF THE DAY...ALLOWING FOR TEMPERATURES TO RISE QUICKLY ABOVE NORMAL. TEMPERATURE RISES HAVE BEEN AIDED...AT LEAST IN PART...BY DOWNSLOPING EASTERLY FLOW SUSTAINED AT 10-15KTS WITH GUSTS CLOSE TO 25KTS. TEMPERATURES THIS EVENING WILL DECREASE ACROSS THE SOUTH FIRST AS THE THICKER CLOUD COVER AND EVENTUAL RAIN SHOWERS MOVE IN. TIMING THE ONSET OF PRECIPITATION HAS BEEN PUSHED BACK AN HOUR OR TWO FOR MOST LOCATIONS TO ACCOUNT FOR THE DRY AIR IN PLACE. KEEPING CATEGORICAL POPS IN FOR THIS EVENING/EARLY TONIGHT...DESPITE SEVERAL OF THE LATEST HRRR RUNS CONTINUING TO SHOW CONSIDERABLE MOISTURE EROSION UPON ARRIVAL...RESULTING IN TRIMMING OF QPF GENERATION. ALL OTHER GUIDANCE INCLUDING THE VARIOUS OTHER HI-RES MODELS SHOW THE CURRENT SWATH OF RAIN ALONG THE WARM FRONT HOLDING TOGETHER THROUGH OUR AREA. TONIGHT THE DRY SLOT IN THE WARM SECTOR WILL RESULT IN A LULL IN PRECIPITATION THAT IS EXPECTED TO LAST THROUGH DAYBREAK. CLOUDS MAY DIMINISH TO THE POINT WHERE POCKETS OF CLEARING COULD AID THE MONDAY MORNING WARM-UP AS STRONG SOUTHEASTERLY FLOW VEERS SOUTHERLY. COLDER AIR ADVANCING EASTWARD ALOFT WILL RESULT IN INSTABILITY AND DRIVE THUNDERSTORM ACTIVITY ALONG AND AHEAD OF THE COLD FRONT. A SLIGHT RISK OF SEVERE THUNDERSTORMS IS INCLUDED FOR OUR AREA...WITH THE MAIN THREAT BEING DAMAGING WINDS. TAX && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... FRONT WILL BE IN OR JUST EAST OF THE RIDGES AT 00Z TUESDAY...WITH A SECONDARY COLD FRONT LAGGING BEHIND WITH THE UPPER LEVEL COLD AIR. ENOUGH MOISTURE AND STEEP ENOUGH LAPSE RATES REMAIN BEHIND THE IMMEDIATE SURFACE BOUNDARY TO KEEP SHRA/TSRA CHANCES GOING THROUGH MUCH OF THE NIGHT. DRIER AIR SHOULD ALLOW PRECIPITATION TO CEASE AREAWIDE BY 12Z. MODELS ARE IN GENERAL AGREEMENT THAT DECAYING MISSISSIPPI VALLEY SHORTWAVE GETS ABSORBED BY DEEPENING UPPER LOW...WHICH DROPS INTO THE NORTHERN GREAT LAKES BY 12Z TUESDAY. THIS LEADS TO A TROUGHING PATTERN FOR THE NORTHEAST U.S. WHICH LOOKS TO PERSIST FOR SOME TIME. CONFIDENCE IS HIGH IN THESE DETAILS. HOWEVER...TIMING OF INDIVIDUAL SHORTWAVES ROTATING AROUND BECOMES MORE PROBLEMATIC WITH TIME. MAIN VORT LOBE RESIDES IN OR NEAR OUR NORTHERN COUNTIES TUESDAY. THIS PLUS BETTER INSTABILITY LEADS TO HIGHER POPS IN THIS AREA TUESDAY AFTERNOON/EVENING. HELD OFF ON THUNDER FOR NOW WITH EQUILIBRIUM LEVELS MOSTLY BELOW 15K FEET...BUT THIS MAY HAVE TO BE REEVALUATED WITH COLD TEMPS ALOFT EXPECTED. A WEAK IMPULSE MAINLY AFFECTS THE SOUTHERN COUNTIES WITH A FEW SHRA TUESDAY NIGHT. THE NEXT...MORE ORGANIZED...FRONTAL BOUNDARY ARRIVES WEDNESDAY WITH BETTER RAIN CHANCES AREAWIDE. BEHIND THE FRONT...BOUNDARY LAYER MAY BE ABLE TO COOL SUFFICIENTLY TO ALLOW SNOWFLAKES TO MIX IN NORTH OF PIT LATE WEDNESDAY NIGHT...BUT NO ACCUMULATION IS FORESEEN. A GENERAL COOLING TREND IN TEMPERATURE WILL BE SEEN WITH VALUES SINKING BELOW NORMAL BY THE END OF THE PERIOD. CL && .LONG TERM /THURSDAY THROUGH SATURDAY/... BROAD UPPER TROUGHING WILL REMAIN OVER THE EASTERN CONUS THROUGH THE EXTENDED AND RESULT IN BELOW NORMAL TEMPERATURES EACH DAY ALONG WITH CLOUDY SKIES AND SLIGHT CHANCES FOR PRECIPITATION THROUGHOUT THE PERIOD AS SHORTWAVES TRANSITION THROUGH THE FLOW AND CAA ALOFT PERSISTS. CONFIDENCE IS HIGH IN THE GENERAL FORECAST AS MODELS HAVE BEEN FAIRLY CONSISTENT IN PROGGING THIS LONGWAVE PATTERN...REFLECTED IN LATEST RMOP AND MODTRENDS GUIDANCE. HOWEVER...CONFIDENCE IN TIMING OF ANY MORE SIGNIFICANT PERIODS OF PRECIPITATION IS RELATIVELY LOW. FORECAST MAX/MIN TEMPERATURES ARE NOT EXCEPTIONALLY COLD...BUT PERSISTENT AROUND 10 DEGREES BELOW NORMALS AS ENSEMBLE ANOMALIES ARE SHOWING TEMPS AND HEIGHTS ALOFT ONLY RANGING FROM 1-2 STANDARD DEVIATIONS BELOW NORMAL THROUGH THE PERIOD. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... HIGH CIRRUS CONTINUES TO MOVE SLOWLY ACROSS THE AREA...BUT NO RESTRICTIONS ARE ANTICIPATED UNTIL THE RAIN SHOWERS ASSOCIATED WITH THE WARM FRONT ARRIVE THIS EVENING. EXPECTING RAIN TO FALL OUT OF MOSTLY VFR CIGS INITIALLY...BUT HEADING INTO THE OVERNIGHT THE CIGS SHOULD CONTINUE THIER DESCENT TO MVFR. CEILINGS MAY BE BROKEN AS WE HEAD INTO MIDDAY MONDAY...WITH THUNDERSTORMS EXPECTED THROUGH AFTERNOON. GUSTY EAST-SOUTHEASTERLY FLOW WILL CONTINUE EVENING AND OVERNIGHT...GRADUALLY RELAXING THROUGH THE EARLY MORNING MONDAY. SURFACE FLOW WILL AGAIN INCREASE AS IT VEERS MORE SOUTHERLY MONDAY AFTERNOON. TAX .OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... RESTRICTIONS ARE POSSIBLE WITH A MID WEEK UPPER TROUGH. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
218 PM EDT SUN APR 19 2015 .SYNOPSIS... SHOWERS WILL OVERSPREAD THE REGION THIS EVENING AND CONTINUE THROUGH MONDAY. UNSEASONABLY COOL TEMPERATURES ARE EXPECTED FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH MONDAY/... DRY AIR SAMPLED BY THE 12Z UPPER AIR SOUNDING REVEALS A SUBSTANTIAL LAYER OF DRY AIR. THIS HAS KEPT THE RAIN AND CLOUDS AT BAY FOR MUCH OF THE DAY...ALLOWING FOR TEMPERATURES TO RISE QUICKLY ABOVE NORMAL. TEMPERATURE RISES HAVE BEEN AIDED...AT LEAST IN PART...BY DOWNSLOPING EASTERLY FLOW SUSTAINED AT 10-15KTS WITH GUSTS CLOSE TO 25KTS. TEMPERATURES THIS EVENING WILL DECREASE ACROSS THE SOUTH FIRST AS THE THICKER CLOUD COVER AND EVENTUAL RAIN SHOWERS MOVE IN. TIMING THE ONSET OF PRECIPITATION HAS BEEN PUSHED BACK AN HOUR OR TWO FOR MOST LOCATIONS TO ACCOUNT FOR THE DRY AIR IN PLACE. KEEPING CATEGORICAL POPS IN FOR THIS EVENING/EARLY TONIGHT...DESPITE SEVERAL OF THE LATEST HRRR RUNS CONTINUING TO SHOW CONSIDERABLE MOISTURE EROSION UPON ARRIVAL...RESULTING IN TRIMMING OF QPF GENERATION. ALL OTHER GUIDANCE INCLUDING THE VARIOUS OTHER HI-RES MODELS SHOW THE CURRENT SWATH OF RAIN ALONG THE WARM FRONT HOLDING TOGETHER THROUGH OUR AREA. TONIGHT THE DRY SLOT IN THE WARM SECTOR WILL RESULT IN A LULL IN PRECIPITATION THAT IS EXPECTED TO LAST THROUGH DAYBREAK. CLOUDS MAY DIMINISH TO THE POINT WHERE POCKETS OF CLEARING COULD AID THE MONDAY MORNING WARM-UP AS STRONG SOUTHEASTERLY FLOW VEERS SOUTHERLY. COLDER AIR ADVANCING EASTWARD ALOFT WILL RESULT IN INSTABILITY AND DRIVE THUNDERSTORM ACTIVITY ALONG AND AHEAD OF THE COLD FRONT. A SLIGHT RISK OF THUNDERSTORMS IS INCLUDED FOR OUR AREA...WITH THE MAIN THREAT BEING DAMAGING WINDS. TAX && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/... SHOWER COVERAGE WILL DECREASE OVERNIGHT AS UPPER LEVEL SUPPORT SHIFTS TO THE EAST AND A LARGE UPPER LEVEL DRY SLOT OVERSPREADS THE AREA. THE RESULTING SUBSIDENCE IS EXPECTED TO CONTINUE THROUGH MONDAY MORNING...AND MAY PROMOTE MODEST HEATING OF A RELATIVELY-MOIST BOUNDARY LAYER WITH 45-50KT OF SOUTHWEST FLOW ALOFT. A SECOND SHORTWAVE TROUGH IS PROJECTED TO MOVE QUICKLY NORTHEASTWARD AND CROSS THE REGION BY LATE DAY. LIFT IN ASSOCIATION WITH THAT DISTURBANCE WOULD AID CONVECTIVE DEVELOPMENT DURING THE AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH THIS SCENARIO. WIDESPREAD SEVERE THUNDERSTORMS ARE NOT EXPECTED OWING TO PROGNOSIS OF WEAK MID LEVEL LAPSE RATES. UNUSUALLY STRONG UPPER LOW PRESSURE IS FORECAST TO BUILD SEWD INTO THE GREAT LAKES REGION BY TUESDAY...WITH ITS ASSOCIATED COLD FRONT TO CROSS THE FORECAST AREA DURING THE MORNING. COLD ADVECTION BEHIND THE FRONTAL PASSAGE IS PROGGED TO PROVIDE INCREASED COVERAGE OF STRATOCU AND POSSIBLE LAKE ENHANCEMENT TO LIGHT PRECIPITATION...WITH THAT LIMITED TO THE NORTHERN ZONES WITH EXPECTATIONS OF WESTERLY FETCH AND DRY ADVECTION. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... BROAD UPPER TROUGHING WILL REMAIN OVER THE EASTERN CONUS THROUGH THE EXTENDED AND RESULT IN BELOW NORMAL TEMPERATURES EACH DAY ALONG WITH CLOUDY SKIES AND SLIGHT CHANCES FOR PRECIPITATION THROUGHOUT THE PERIOD AS SHORTWAVES TRANSITION THROUGH THE FLOW AND CAA ALOFT PERSISTS. CONFIDENCE IS HIGH IN THE GENERAL FORECAST AS MODELS HAVE BEEN FAIRLY CONSISTENT IN PROGGING THIS LONGWAVE PATTERN...REFLECTED IN LATEST RMOP AND MODTRENDS GUIDANCE. HOWEVER...CONFIDENCE IN TIMING OF ANY MORE SIGNIFICANT PERIODS OF PRECIPITATION IS RELATIVELY LOW. FORECAST MAX/MIN TEMPERATURES ARE NOT EXCEPTIONALLY COLD...BUT PERSISTENT AROUND 10 DEGREES BELOW NORMALS AS ENSEMBLE ANOMALIES ARE SHOWING TEMPS AND HEIGHTS ALOFT ONLY RANGING FROM 1-2 STANDARD DEVIATIONS BELOW NORMAL THROUGH THE PERIOD. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... HIGH CIRRUS CONTINUES TO MOVE SLOWLY ACROSS THE AREA...BUT NO RESTRICTIONS ARE ANTICIPATED UNTIL THE RAIN SHOWERS ASSOCIATED WITH THE WARM FRONT ARRIVE THIS EVENING. EXPECTING RAIN TO FALL OUT OF MOSTLY VFR CIGS INITIALLY...BUT HEADING INTO THE OVERNIGHT THE CIGS SHOULD CONTINUE THIER DESCENT TO MVFR. CEILINGS MAY BE BROKEN AS WE HEAD INTO MIDDAY MONDAY...WITH THUNDERSTORMS EXPECTED THROUGH AFTERNOON. GUSTY EAST-SOUTHEASTERLY FLOW WILL CONTINUE EVENING AND OVERNIGHT...GRADUALLY RELAXING THROUGH THE EARLY MORNING MONDAY. SURFACE FLOW WILL AGAIN INCREASE AS IT VEERS MORE SOUTHERLY MONDAY AFTERNOON. TAX .OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... RESTRICTIONS ARE POSSIBLE WITH A MID WEEK UPPER TROUGH. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
747 PM EDT MON APR 20 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 353 PM EDT MON APR 20 2015 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEPENING UPR TROF OVER CENTRAL NAMERICA BTWN RDGS ALONG THE E AND W COASTS...WITH 12HR H5 HGT FALLS UP TO 150M NOTED OVER NRN WI IN ADVANCE OF SHRTWV LIFTING NWD INTO THE UPR LKS TO THE E OF THE UPR TROF AXIS. IR AND WV IMAGERY SHOW A WELL DEFINED COMMA HEAD CLD OVER THE UPR GREAT LKS IN ADVANCE OF SHRTWV AND ON CYC SIDE OF ACCOMPANYING H7 LO TRACK. STEADY RA UNDER THIS COMMA HEAD HAS MIXED WITH SN OVER THE WRN CWA WHERE DYNAMIC COOLING AND SOME LLVL CAA HAVE COOLED THE COLUMN SUFFICIENTLY. FARTHER TO THE E...DRY SLOTTING ON THE ACYC SIDE OF H7 LO TRACK HAS TENDED TO DIMINISH THE PCPN COVERAGE/INTENSITY OVER THE FAR E. ANOTHER SHRTWV IS DIGGING SWD THRU FAR NW ONTARIO/MANITOBA ON THE WRN FLANK OF H5 CLOSED LO MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON POPS/PTYPE ASSOCIATED WITH SHRTWV MOVING THRU THE UPR LKS RIGHT NOW AND THEN TNGT/TMRW ACCOMPANYING PASSAGE OF NEXT SHRTWV AND WITHIN LINGERING DEEP CYC FLOW UNDER CUTOFF H5 LO PROGGED TO LINGER OVER THE UPR LKS. LATE TDAY/TNGT...AS SHRTWV E OF THE UPR TROF AXIS LIFTS TO THE N THRU THIS AFTN AND TENDS TO SHEAR OUT...MODELS SHOW AREA OF SHARP DEEP LYR QVECTOR CNVGC SUPPORTING AXIS OF COLDER CLD TOPS DIMINISHING AND GIVING WAY TO SOME DEEP LYR QVECTOR DVGC. SO AREA OF STEADY RA/SN OVER THE W SHOULD DIMINISH BY LATE AFTN WITH ARRIVAL OF THE NEGATIVE DYNAMICS/MID LVL DRYING. POPS OVER THE E WL TEND TO INCREASE LATE THIS AFTN/EARLY EVNG AS COMMA TAIL AXIS OF HIER RH SWINGS E THRU THAT AREA...BUT PCPN INTENSITY WL NOT BE AS GREAT AS OVER THE W SINCE THE SUPPORTING AXIS OF DIMINISHING DEEP LYR QVECTOR CNVGC IS FCST TO REMAIN OVER THE W. NOT OUT OF THE QUESTION THERE COULD BE A FEW INCHES OF WET SN ACCUM OVER THE HIER TERRAIN OF THE W...BUT THERE SHOULD BE LTL IF ANY SN OVER THE E HALF WITH WEAKER DYNAMIC FORCING/COOLING. LATER TNGT...THE TRAILING SHRTWV DIGGING SWD TOWARD NW MN ON THE WRN FLANK OF CLOSED H5 LO IS FCST TO DIG TO NEAR NW WI BY 12Z TUE...BRINGING SOME DPVA/MORE DEEP LYR QVECTOR CNVGC TO THE W LATER TNGT. SHARP CYC UPSLOPE WNW FLOW IN THE PRESENCE OF THE DEEPER FORCING/MSTR WL SUPPORT LIKELY POPS IN THIS AREA. THERE COULD BE A FEW INCHES OF WET SN ACCUM OVER MAINLY THE HIER TERRAIN. OVER THE CENTRAL AND E...THERE WL BE ONLY ISOLD-SCT RA AND SN SHOWERS. TUE...SHRTWV/ACCOMPANYING SFC LO PRES TROF ROTATING ARND CLOSED H5 LO SHIFTING SLOWLY TO THE E OVER LK SUP IS FCST TO WEAKEN SLOWLY... LEADING TO SLOWLY DIMINISHING DEEP LYR QVECTOR CNVGC. ALTHOUGH THESE TRENDS WL RESULT IN DIMINISHING POPS...DAYTIME HEATING/LLVL DESTABILIZATION WL ENHANCE POPS ESPECIALLY OVER THE ERN CWA IN THE AFTN...WHERE LLVL CNVGC WITHIN LO PRES TROF WL BE ENHANCED BY LK BREEZE DEVELOPMENT. OTRW...LINGERING SHARP LLVL CNVGC AND THE DAYTIME HEATING WL MAINTAIN AT LEAST CHC POPS. THE PCPN SHOULD BE MAINLY SN IN THE MRNG...BUT THIS PCPN WL MIX WITH/CHG TO RA OVER THE SE HALF IN THE AFTN WITH DAYTIME HEATING/TEMPS RISING AOA 40. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 338 PM EDT MON APR 20 2015 A LARGE UPPER LOW CENTERED OVER NORTHERN ONTARIO WILL BE INFLUENCING THE GREAT LAKES REGION THROUGH THE FIRST HALF OF THE LONG TERM PERIOD. THIS WILL LEAD TO BELOW NORMAL TEMPERATURES AND PERIODS OF SNOW BEFORE GRADUALLY SHIFTING EAST INTO THE ATLANTIC BY THE WEEKEND. AS THAT UPPER LOW SPINS BETWEEN LAKE SUPERIOR AND JAMES BAY...IT WILL ROTATE SEVERAL SHORTWAVES ACROSS THE UPPER GREAT LAKES REGION TUESDAY NIGHT THROUGH THURSDAY. THESE WAVES WILL BRING PERIODS OF SHOWERS TO THE AREA...WITH HELP FROM BOTH LAKE SUPERIOR (850MB TEMPS FALLING TO -10C TO -12C ON WEDNESDAY MORNING) AND TERRAIN ENHANCEMENT (PERSISTENT LOW LEVEL NORTHWESTERLY FLOW). WILL CONTINUE TO FOCUS THE HIGHEST POPS (LIKELY VALUES) IN THOSE AREAS FAVORED BY ALL THREE FEATURES (HIGHER TERRAIN OF THE WEST/NORTHWEST) AND ALSO EAST DOWNWIND OF LAKE SUPERIOR...AND INCLUDE CHANCE/SLIGHTS FOR THE REST OF THE CWA. WITH THE AMOUNT OF COLD AIR IN PLACE...EXPECT THE PRECIPITATION TO FALL MAINLY AS SNOW. WITH LOW LEVEL TEMPERATURES WARMING AWAY OVER THE SOUTHERN THIRD OF THE CWA...COULD SEE SOME RAIN MIXING IN THERE...BUT OTHERWISE SNOW WILL BE THE NORM. COULD SEE A COUPLE INCHES OF ACCUMULATION IN THE FAVORED LOCATIONS TUESDAY NIGHT AND UP TO AN INCH WEDNESDAY AND AGAIN WEDNESDAY NIGHT. WITH DRIER AIR STARTING TO MOVE INTO THE AREA ON THURSDAY (ASSOCIATED WITH A SURFACE RIDGE MOVING INTO THE NORTHERN PLAINS...SHOULD SEE THE COVERAGE OF THE SHOWERS DIMINISHING THROUGH THE DAY THURSDAY AND CONTINUING TO WEAKENING INTO FRIDAY. ALSO...DON/T EXPECT HIGHS TO RISE MUCH OUT OF THE LOW-MID 30S ON WED/THURS OVER THE NORTH HALF OF THE CWA...WITH SOME HIGHS AROUND 40 OVER THE SOUTH CENTRAL. WILL LIKELY BREAK THE RECORD LOW HIGH TEMPERATURE HERE AT OUR OFFICE ON WEDNESDAY (36 SET IN 1972). EXTENDED RANGE MODELS DIFFER ON HOW QUICKLY THE UPPER LOW DEPARTS THIS WEEKEND...BUT SHOULD STILL SEE ENOUGH INFLUENCE FROM THE SURFACE RIDGE MOVING INTO THE NORTHERN PLAINS TO KEEP MOST OF THE AREA DRY. WITH THE NORTHERLY FLOW OFF LAKE SUPERIOR...EXPECT TEMPERATURES TO REMAIN BELOW NORMAL BUT IN THE 40S TO AROUND 50. AS THE UPPER LOW RETROGRADES BACK OVER QUEBEC EARLY NEXT WEEK...COULD SEE THE UPPER GREAT LAKES REGION BEING AFFECTED BY THE WESTERN EDGE OF THE ENERGY ROTATING AROUND THE UPPER LOW AND LIKELY KEEPING BELOW NORMAL TEMPERATURES IN PLACE THROUGH THE END OF APRIL. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 747 PM EDT MON APR 20 2015 AREA OF DEEPER MOISTURE AND STEADIER SNOW CONTINUES TO LIFT NE ACROSS UPPER MI/LAKE SUPERIOR. BEHIND THIS DEEPER MOISTURE/STEADIER SNOW...EXPECT MVFR CONDITIONS WITH -SHSN AT TIMES TO PREVAIL AT KIWD THIS EVENING. AT KCMX...IFR CONDITIONS SHOULD IMPROVE TO MVFR IN THE NEXT HR OR TWO. AT KSAW...IT`S POSSIBLE MVFR CONDITIONS COULD IMPROVE TO VFR AT TIMES THIS EVENING. APPROACH OF ANOTHER DISTURBANCE/LOW PRES TROF LATER TONIGHT SHOULD RESULT IN DETERIORATING CONDITIONS TO IFR AT KIWD/KCMX. DOWNSLOPE WIND W TO SW WINDS AT KSAW WILL RESTRICT THE IMPACT THERE...SO MVFR CIGS SHOULD PREVAIL. AFTER THIS DISTURBANCE EXITS TO THE E...EXPECT MVFR CONDITIONS TO RETURN TO KIWD/KCMX MID TO LATE MORNING ON TUE. -SHSN WILL CONTINUE AT ALL TERMINALS TUE...AND IT`S NOT OUT OF THE QUESTION THAT IFR VIS COULD OCCUR AT TIMES...ESPECIALLY AT KIWD/KSAW AS DAYTIME HEATING/INSTABILITY AIDS -SHSN INTENSITY. WINDS WILL GENERALLY REMAIN GUSTY...PARTICULARLY AT KCMX WHERE GUSTS OF 25-30KT SHOULD BE COMMON FOR MUCH OF THE FCST PERIOD. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 353 PM EDT MON APR 20 2015 SHARP PRES GRADIENT ON THE SW FLANK OF SLOW MOVING LO PRES IN ONTARIO WILL CAUSE W TO NW WINDS UP TO 25-30 KTS INTO THU. ALTHOUGH THERE COULD BE SOME GALE FORCE GUSTS AT TIMES...WIDESPREAD GALES ARE NOT EXPECTED. THE CLOSER APPROACH OF HI PRES LATER IN THE WEEK WILL RESULT IN NW WINDS DIMINISHING TO NO MORE THAN 20 KTS ON FRI AND SAT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...SRF AVIATION...ROLFSON MARINE...KC
AREA FORECAST DISCUSSION
NWS DULUTH MN
1220 PM CDT SUN APR 19 2015 .UPDATE... ISSUED AT 945 AM CDT SUN APR 19 2015 RAIN WILL CONTINUE TO AFFECT THE FORECAST AREA THROUGH THE DAY. HOWEVER...THERE WILL BE AN HOUR OR TWO WHEN NO RAIN IS OCCURRING AND TRIED TO ACCOUNT FOR THIS IN THE FORECAST. KEPT THE MAX TEMPS THE SAME FOR NOW...BUT WILL LOOK INTO LOWERING LATER TODAY. REST OF THE FORECAST IN THE BALLPARK. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 342 AM CDT SUN APR 19 2015 THE FOCUS REMAINS ON THE RAIN TODAY AND TONIGHT. REFINED THE PCPN CHANCES BY USING A BLEND OF THE RAP13 AND HRRR MODEL RUNS THROUGH THIS MORNING SINCE THE TWO MODELS SEEM TO BE DOING PRETTY WELL CAPTURING THE LOCATION OF THE CURRENT RAIN. DID NOT MAKE ANY DRAMATIC CHANGES TO RAINFALL. OVERALL...MUCH OF THE FORECAST AREA CAN EXPECT ABOUT 0.30 TO 0.75 INCHES OF RAINFALL THROUGH TONIGHT. AT 330 AM...AN AREA OF LOW PRESSURE WAS OVER THE BORDER BETWEEN SOUTH DAKOTA AND SW MINNESOTA. A FRONTAL BOUNDARY EXTENDED NORTHWARD TO ANOTHER AREA OF LOW PRESSURE IN SOUTHERN MANITOBA. THERE WAS AN UPPER LEVEL TROUGH OVER THE NORTHERN HIGH PLAINS AND SASKATCHEWAN/MANITOBA DIGGING AND DEEPENING TOWARDS THE NORTHERN PLAINS AND ONTARIO. A LARGE AREA OF RAIN WAS LIFTING TO NNE THROUGH THE SOUTHERN TWO THIRDS OF THE FORECAST AREA. THIS RAIN WAS ASSOCIATED WITH A BAND OF MID LEVEL FRONTOGENESIS AHEAD OF THE LOW NEAR THE SD/MN BORDER. THERE WAS ADDITIONAL RAIN IN EASTERN SOUTH DAKOTA AND NW MINNESOTA MOVING TO THE EAST IN THE WAKE OF THE TROUGH BOUNDARY AND AHEAD OF THE UPPER LEVEL TO THE WEST. THE NORTHLAND HAD CLOUDY SKIES WITH TEMPERATURES IN THE UPPER 30S TO MIDDLE 40S. THE NORTHLAND HAD LIGHT EASTERLY TO SOUTHEASTERLY WINDS. THIS MORNING...THE SURFACE LOW NEAR THE SD/MN BORDER WILL LIFT NE TO THE AITKIN AREA BY THIS AFTERNOON. THE SURFACE LOW IN SOUTHERN MANITOBA WILL DIG TO THE SE. THE RAIN OVER THE FORECAST AREA EARLY THIS MORNING WILL CONTINUE LIFTING TO THE NORTH WITH THE BAND OF MID LEVEL FRONTOGENESIS. PARTS OF THE NORTHERN FORECAST COULD PICK UP TO AROUND A HALF INCH OF RAIN THROUGH THIS MORNING. THE COLD FRONT IN NORTH DAKOTA WILL BEGIN TO MOVE INTO THE WESTERN FORECAST AREA LATE THIS MORNING. THIS AFTERNOON AND EVENING...THE TWO LOWS WILL GRADUALLY MERGE INTO ONE LOW OVER NW ONTARIO. CLOUDY AND COOL WEATHER IS EXPECTED WITH HIGHS RANGING FROM THE UPPER 40S OVER THE NORTH TO THE 50S OVER THE SOUTH. MOST OF THE AFTERNOON AND EVENING RAIN WILL BE OVER THE EASTERN FORECAST AREA AHEAD OF THE EASTWARD ADVANCING COLD FRONT. A DRY SLOT WILL MOVE INTO THE WESTERN FORECAST AREA...AND THERE COULD BE PARTIAL CLEARING IN THE SW FORECAST AREA. ALSO...A PROMINENT BAND OF LOW/MID LEVEL FRONTOGENESIS WILL SET UP OVER NW WISCONSIN THIS EVENING WHICH DEVELOP AND INTENSIFY A BAND OF RAIN OVER THAT AREA. THE UPPER LEVEL TROUGH OVER THE NORTHERN PLAINS AND SOUTH CENTRAL CANADA WILL DEEPEN AND DEVELOP INTO A WELL DEFINED UPPER LEVEL OVER SOUTHERN MANITOBA THIS AFTERNOON AND CONTINUE DEEPENING AS IT APPROACHES NORTHERN MANITOBA. LATER TONIGHT AND EARLY MONDAY...THE COLD FRONT WILL FINISH MOVING THROUGH THE FORECAST AREA. THE UPPER LEVEL LOW WILL CONTINUE DEEPENING OVER NW ONTARIO. THE LOW/MID LEVEL FRONTOGENETICAL BAND IN NW WISCONSIN SHOULD EXIT TO THE EAST BY AROUND DAWN. TEMPERATURES WILL DROP INTO THE MIDDLE AND LOWER 30S TONIGHT. THE SYNOPTIC LIFT FROM THE UPPER LEVEL LOW WILL LIKELY RESULT IN LIGHT RAIN AND SNOW MOVING INTO THE NW FORECAST AREA. LITTLE OF ANY SNOW ACCUMULATION IS EXPECTED SINCE MUCH OF IT SHOULD MELT...EITHER ON IMPACT OR LATER IN THE MORNING. MONDAY...IT WILL BE MUCH COOLER DAY WITH BLUSTERY NW WINDS. SUSTAINED WINDS OF 10 TO 20 MPH WILL DEVELOP BY THE AFTERNOON...AND THERE COULD BE GUSTS UP TO 30 MPH. THE 850 HPA TEMPERATURES WILL BE ABOUT -5 TO -6 DEGREES CELSIUS. HEAVY CLOUD COVER AND THE COOL NW FLOW WILL PREVENT HIGHS FROM GETTING MUCH HIGHER THAN THE LOW TO MIDDLE 40S. THERE WILL BE INCREASING CHANCES OF COLD RAIN SHOWERS AS THE UPPER LOW DEEPENS AND MOVES TO JUST NORTH OF KOOCHICHING COUNTY. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 342 AM CDT SUN APR 19 2015 A DEEP AREA OF LOW PRESSURE WILL SETTLE SOUTHWARD INTO THE LAKE SUPERIOR REGION MONDAY NIGHT AND TUESDAY. THE CLOSED H5 LOW WILL REACH WESTERN LAKE SUPERIOR BY TUESDAY AFTERNOON. NUMEROUS SHOWERS WILL ROTATE SOUTHWARD AROUND THE UPPER LOW...GENERALLY IN THE FORM OF SNOW SHOWERS AT NIGHT AND RAIN OR SNOW SHOWERS DURING THE DAY THROUGH THE MIDDLE OF THE WEEK. DEFINITELY COULD BE SOME SLUSHY ACCUMULATION AT TIMES...ESPECIALLY IN THE NORTH. WOULD NOT BE SURPRISED TO SEE A COUPLE EPISODES OF UP TO A COUPLE INCHES... FOLLOWED BY SOME PARTIAL TO FULL MELTING DURING THE DAY. THIS MASSIVE UPPER LEVEL TROUGH WILL EVENTUALLY LOSE ITS GRIP ON THE AREA FROM THE MIDDLE TO THE END OF THE WORK WEEK. THE GEM AND TO SOME EXTENT THE ECMWF ARE THE MOST AGGRESSIVE IN PUSHING THE UPPER TROUGH EASTWARD THROUGH THE END OF THE WEEK...WITH THE GEM BRINGING UPPER LEVEL RIDGING ALREADY INTO THE CWA BY 12Z FRIDAY. THE GFS IS MUCH SLOWER AND DEEPER WITH THE UPPER LEVEL LOW. STRONGLY FAVORING THE GEM/ECMWF SOLUTION...ESPECIALLY LATE IN THE WEEK AND INTO THE WEEKEND. HIGH TEMPERATURES WILL REMAIN ON THE COOL SIDE DURING THE WEEK...REACHING BACK INTO THE LOW TO MID 50S ON THE WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1220 PM CDT SUN APR 19 2015 CONDITIONS VARIED FROM LIFR TO MVFR ACROSS THE NORTHLAND WITH PERIODS OF RAIN/FOG/DRIZZLE MOVING THROUGH THE AREA. THESE CONDITIONS WILL PERSIST THROUGH THE AFTERNOON INTO TONIGHT. THE RAIN WILL BE MOST WIDESPREAD OVER EASTERN AREAS...ESPECIALLY NORTHWEST WISCONSIN TONIGHT. SOUTHWEST AREAS INCLUDING KBRD MAY GO VFR BRIEFLY LATER THIS EVENING...BUT AS COLDER AIR MOVES BACK IN ON THE BACKSIDE OF THE LOW...LOWER CEILINGS WILL ONCE AGAIN RETURN. TEMPERATURES MAY GET COLD ENOUGH FOR SOME SNOW OVER PORTIONS OF NORTHERN MINNESOTA LATER TONIGHT. GUSTY WEST/NORTHWEST WINDS WILL ALSO DEVELOP LATER IN THE PERIOD...ESPECIALLY ON MONDAY. && .PRELIMINARY POINT TEMPS/POPS... DLH 49 34 44 29 / 90 30 30 60 INL 49 32 40 28 / 100 40 60 60 BRD 56 35 43 31 / 80 20 40 40 HYR 58 37 46 30 / 90 80 30 60 ASX 58 37 47 32 / 90 80 20 60 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ142>147. && $$ UPDATE...GSF SHORT TERM...GROCHOCINSKI LONG TERM...DAP AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS DULUTH MN
949 AM CDT SUN APR 19 2015 .UPDATE... ISSUED AT 945 AM CDT SUN APR 19 2015 RAIN WILL CONTINUE TO AFFECT THE FORECAST AREA THROUGH THE DAY. HOWEVER...THERE WILL BE AN HOUR OR TWO WHEN NO RAIN IS OCCURRING AND TRIED TO ACCOUNT FOR THIS IN THE FORECAST. KEPT THE MAX TEMPS THE SAME FOR NOW...BUT WILL LOOK INTO LOWERING LATER TODAY. REST OF THE FORECAST IN THE BALLPARK. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 342 AM CDT SUN APR 19 2015 THE FOCUS REMAINS ON THE RAIN TODAY AND TONIGHT. REFINED THE PCPN CHANCES BY USING A BLEND OF THE RAP13 AND HRRR MODEL RUNS THROUGH THIS MORNING SINCE THE TWO MODELS SEEM TO BE DOING PRETTY WELL CAPTURING THE LOCATION OF THE CURRENT RAIN. DID NOT MAKE ANY DRAMATIC CHANGES TO RAINFALL. OVERALL...MUCH OF THE FORECAST AREA CAN EXPECT ABOUT 0.30 TO 0.75 INCHES OF RAINFALL THROUGH TONIGHT. AT 330 AM...AN AREA OF LOW PRESSURE WAS OVER THE BORDER BETWEEN SOUTH DAKOTA AND SW MINNESOTA. A FRONTAL BOUNDARY EXTENDED NORTHWARD TO ANOTHER AREA OF LOW PRESSURE IN SOUTHERN MANITOBA. THERE WAS AN UPPER LEVEL TROUGH OVER THE NORTHERN HIGH PLAINS AND SASKATCHEWAN/MANITOBA DIGGING AND DEEPENING TOWARDS THE NORTHERN PLAINS AND ONTARIO. A LARGE AREA OF RAIN WAS LIFTING TO NNE THROUGH THE SOUTHERN TWO THIRDS OF THE FORECAST AREA. THIS RAIN WAS ASSOCIATED WITH A BAND OF MID LEVEL FRONTOGENESIS AHEAD OF THE LOW NEAR THE SD/MN BORDER. THERE WAS ADDITIONAL RAIN IN EASTERN SOUTH DAKOTA AND NW MINNESOTA MOVING TO THE EAST IN THE WAKE OF THE TROUGH BOUNDARY AND AHEAD OF THE UPPER LEVEL TO THE WEST. THE NORTHLAND HAD CLOUDY SKIES WITH TEMPERATURES IN THE UPPER 30S TO MIDDLE 40S. THE NORTHLAND HAD LIGHT EASTERLY TO SOUTHEASTERLY WINDS. THIS MORNING...THE SURFACE LOW NEAR THE SD/MN BORDER WILL LIFT NE TO THE AITKIN AREA BY THIS AFTERNOON. THE SURFACE LOW IN SOUTHERN MANITOBA WILL DIG TO THE SE. THE RAIN OVER THE FORECAST AREA EARLY THIS MORNING WILL CONTINUE LIFTING TO THE NORTH WITH THE BAND OF MID LEVEL FRONTOGENESIS. PARTS OF THE NORTHERN FORECAST COULD PICK UP TO AROUND A HALF INCH OF RAIN THROUGH THIS MORNING. THE COLD FRONT IN NORTH DAKOTA WILL BEGIN TO MOVE INTO THE WESTERN FORECAST AREA LATE THIS MORNING. THIS AFTERNOON AND EVENING...THE TWO LOWS WILL GRADUALLY MERGE INTO ONE LOW OVER NW ONTARIO. CLOUDY AND COOL WEATHER IS EXPECTED WITH HIGHS RANGING FROM THE UPPER 40S OVER THE NORTH TO THE 50S OVER THE SOUTH. MOST OF THE AFTERNOON AND EVENING RAIN WILL BE OVER THE EASTERN FORECAST AREA AHEAD OF THE EASTWARD ADVANCING COLD FRONT. A DRY SLOT WILL MOVE INTO THE WESTERN FORECAST AREA...AND THERE COULD BE PARTIAL CLEARING IN THE SW FORECAST AREA. ALSO...A PROMINENT BAND OF LOW/MID LEVEL FRONTOGENESIS WILL SET UP OVER NW WISCONSIN THIS EVENING WHICH DEVELOP AND INTENSIFY A BAND OF RAIN OVER THAT AREA. THE UPPER LEVEL TROUGH OVER THE NORTHERN PLAINS AND SOUTH CENTRAL CANADA WILL DEEPEN AND DEVELOP INTO A WELL DEFINED UPPER LEVEL OVER SOUTHERN MANITOBA THIS AFTERNOON AND CONTINUE DEEPENING AS IT APPROACHES NORTHERN MANITOBA. LATER TONIGHT AND EARLY MONDAY...THE COLD FRONT WILL FINISH MOVING THROUGH THE FORECAST AREA. THE UPPER LEVEL LOW WILL CONTINUE DEEPENING OVER NW ONTARIO. THE LOW/MID LEVEL FRONTOGENETICAL BAND IN NW WISCONSIN SHOULD EXIT TO THE EAST BY AROUND DAWN. TEMPERATURES WILL DROP INTO THE MIDDLE AND LOWER 30S TONIGHT. THE SYNOPTIC LIFT FROM THE UPPER LEVEL LOW WILL LIKELY RESULT IN LIGHT RAIN AND SNOW MOVING INTO THE NW FORECAST AREA. LITTLE OF ANY SNOW ACCUMULATION IS EXPECTED SINCE MUCH OF IT SHOULD MELT...EITHER ON IMPACT OR LATER IN THE MORNING. MONDAY...IT WILL BE MUCH COOLER DAY WITH BLUSTERY NW WINDS. SUSTAINED WINDS OF 10 TO 20 MPH WILL DEVELOP BY THE AFTERNOON...AND THERE COULD BE GUSTS UP TO 30 MPH. THE 850 HPA TEMPERATURES WILL BE ABOUT -5 TO -6 DEGREES CELSIUS. HEAVY CLOUD COVER AND THE COOL NW FLOW WILL PREVENT HIGHS FROM GETTING MUCH HIGHER THAN THE LOW TO MIDDLE 40S. THERE WILL BE INCREASING CHANCES OF COLD RAIN SHOWERS AS THE UPPER LOW DEEPENS AND MOVES TO JUST NORTH OF KOOCHICHING COUNTY. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 342 AM CDT SUN APR 19 2015 A DEEP AREA OF LOW PRESSURE WILL SETTLE SOUTHWARD INTO THE LAKE SUPERIOR REGION MONDAY NIGHT AND TUESDAY. THE CLOSED H5 LOW WILL REACH WESTERN LAKE SUPERIOR BY TUESDAY AFTERNOON. NUMEROUS SHOWERS WILL ROTATE SOUTHWARD AROUND THE UPPER LOW...GENERALLY IN THE FORM OF SNOW SHOWERS AT NIGHT AND RAIN OR SNOW SHOWERS DURING THE DAY THROUGH THE MIDDLE OF THE WEEK. DEFINITELY COULD BE SOME SLUSHY ACCUMULATION AT TIMES...ESPECIALLY IN THE NORTH. WOULD NOT BE SURPRISED TO SEE A COUPLE EPISODES OF UP TO A COUPLE INCHES... FOLLOWED BY SOME PARTIAL TO FULL MELTING DURING THE DAY. THIS MASSIVE UPPER LEVEL TROUGH WILL EVENTUALLY LOSE ITS GRIP ON THE AREA FROM THE MIDDLE TO THE END OF THE WORK WEEK. THE GEM AND TO SOME EXTENT THE ECMWF ARE THE MOST AGGRESSIVE IN PUSHING THE UPPER TROUGH EASTWARD THROUGH THE END OF THE WEEK...WITH THE GEM BRINGING UPPER LEVEL RIDGING ALREADY INTO THE CWA BY 12Z FRIDAY. THE GFS IS MUCH SLOWER AND DEEPER WITH THE UPPER LEVEL LOW. STRONGLY FAVORING THE GEM/ECMWF SOLUTION...ESPECIALLY LATE IN THE WEEK AND INTO THE WEEKEND. HIGH TEMPERATURES WILL REMAIN ON THE COOL SIDE DURING THE WEEK...REACHING BACK INTO THE LOW TO MID 50S ON THE WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 656 AM CDT SUN APR 19 2015 A LARGE AREA OF LOW PRESSURE WILL CONTINUE TO MOVE NORTHEAST INTO THE NORTHLAND TODAY AND TONIGHT. ABUNDANT MOISTURE THROUGH THE PLAINS WILL CONTINUE TO BRING AREAS OF LIGHT RAIN TODAY INTO TONIGHT. CLOUD HEIGHTS ARE EXPECTED TO GRADUALLY DECREASE TO MVFR OR EVEN IFR DURING THE MORNING...AND REMAIN THAT WAY THROUGH THE AFTERNOON. SOME IMPROVEMENT IN CLOUD HEIGHTS WILL BE POSSIBLE FROM THE WEST...AS SOMEWHAT DRIER AIR PUSHES EASTWARD BEHIND A COLD FRONT. && .PRELIMINARY POINT TEMPS/POPS... DLH 49 34 44 29 / 90 30 30 60 INL 49 32 40 28 / 100 40 60 60 BRD 56 35 43 31 / 80 20 40 40 HYR 58 37 46 30 / 90 80 30 60 ASX 58 37 47 32 / 80 80 20 60 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ142>147. && $$ UPDATE...GSF SHORT TERM...GROCHOCINSKI LONG TERM...DAP AVIATION...DAP
AREA FORECAST DISCUSSION
NWS DULUTH MN
701 AM CDT SUN APR 19 2015 .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 342 AM CDT SUN APR 19 2015 THE FOCUS REMAINS ON THE RAIN TODAY AND TONIGHT. REFINED THE PCPN CHANCES BY USING A BLEND OF THE RAP13 AND HRRR MODEL RUNS THROUGH THIS MORNING SINCE THE TWO MODELS SEEM TO BE DOING PRETTY WELL CAPTURING THE LOCATION OF THE CURRENT RAIN. DID NOT MAKE ANY DRAMATIC CHANGES TO RAINFALL. OVERALL...MUCH OF THE FORECAST AREA CAN EXPECT ABOUT 0.30 TO 0.75 INCHES OF RAINFALL THROUGH TONIGHT. AT 330 AM...AN AREA OF LOW PRESSURE WAS OVER THE BORDER BETWEEN SOUTH DAKOTA AND SW MINNESOTA. A FRONTAL BOUNDARY EXTENDED NORTHWARD TO ANOTHER AREA OF LOW PRESSURE IN SOUTHERN MANITOBA. THERE WAS AN UPPER LEVEL TROUGH OVER THE NORTHERN HIGH PLAINS AND SASKATCHEWAN/MANITOBA DIGGING AND DEEPENING TOWARDS THE NORTHERN PLAINS AND ONTARIO. A LARGE AREA OF RAIN WAS LIFTING TO NNE THROUGH THE SOUTHERN TWO THIRDS OF THE FORECAST AREA. THIS RAIN WAS ASSOCIATED WITH A BAND OF MID LEVEL FRONTOGENESIS AHEAD OF THE LOW NEAR THE SD/MN BORDER. THERE WAS ADDITIONAL RAIN IN EASTERN SOUTH DAKOTA AND NW MINNESOTA MOVING TO THE EAST IN THE WAKE OF THE TROUGH BOUNDARY AND AHEAD OF THE UPPER LEVEL TO THE WEST. THE NORTHLAND HAD CLOUDY SKIES WITH TEMPERATURES IN THE UPPER 30S TO MIDDLE 40S. THE NORTHLAND HAD LIGHT EASTERLY TO SOUTHEASTERLY WINDS. THIS MORNING...THE SURFACE LOW NEAR THE SD/MN BORDER WILL LIFT NE TO THE AITKIN AREA BY THIS AFTERNOON. THE SURFACE LOW IN SOUTHERN MANITOBA WILL DIG TO THE SE. THE RAIN OVER THE FORECAST AREA EARLY THIS MORNING WILL CONTINUE LIFTING TO THE NORTH WITH THE BAND OF MID LEVEL FRONTOGENESIS. PARTS OF THE NORTHERN FORECAST COULD PICK UP TO AROUND A HALF INCH OF RAIN THROUGH THIS MORNING. THE COLD FRONT IN NORTH DAKOTA WILL BEGIN TO MOVE INTO THE WESTERN FORECAST AREA LATE THIS MORNING. THIS AFTERNOON AND EVENING...THE TWO LOWS WILL GRADUALLY MERGE INTO ONE LOW OVER NW ONTARIO. CLOUDY AND COOL WEATHER IS EXPECTED WITH HIGHS RANGING FROM THE UPPER 40S OVER THE NORTH TO THE 50S OVER THE SOUTH. MOST OF THE AFTERNOON AND EVENING RAIN WILL BE OVER THE EASTERN FORECAST AREA AHEAD OF THE EASTWARD ADVANCING COLD FRONT. A DRY SLOT WILL MOVE INTO THE WESTERN FORECAST AREA...AND THERE COULD BE PARTIAL CLEARING IN THE SW FORECAST AREA. ALSO...A PROMINENT BAND OF LOW/MID LEVEL FRONTOGENESIS WILL SET UP OVER NW WISCONSIN THIS EVENING WHICH DEVELOP AND INTENSIFY A BAND OF RAIN OVER THAT AREA. THE UPPER LEVEL TROUGH OVER THE NORTHERN PLAINS AND SOUTH CENTRAL CANADA WILL DEEPEN AND DEVELOP INTO A WELL DEFINED UPPER LEVEL OVER SOUTHERN MANITOBA THIS AFTERNOON AND CONTINUE DEEPENING AS IT APPROACHES NORTHERN MANITOBA. LATER TONIGHT AND EARLY MONDAY...THE COLD FRONT WILL FINISH MOVING THROUGH THE FORECAST AREA. THE UPPER LEVEL LOW WILL CONTINUE DEEPENING OVER NW ONTARIO. THE LOW/MID LEVEL FRONTOGENETICAL BAND IN NW WISCONSIN SHOULD EXIT TO THE EAST BY AROUND DAWN. TEMPERATURES WILL DROP INTO THE MIDDLE AND LOWER 30S TONIGHT. THE SYNOPTIC LIFT FROM THE UPPER LEVEL LOW WILL LIKELY RESULT IN LIGHT RAIN AND SNOW MOVING INTO THE NW FORECAST AREA. LITTLE OF ANY SNOW ACCUMULATION IS EXPECTED SINCE MUCH OF IT SHOULD MELT...EITHER ON IMPACT OR LATER IN THE MORNING. MONDAY...IT WILL BE MUCH COOLER DAY WITH BLUSTERY NW WINDS. SUSTAINED WINDS OF 10 TO 20 MPH WILL DEVELOP BY THE AFTERNOON...AND THERE COULD BE GUSTS UP TO 30 MPH. THE 850 HPA TEMPERATURES WILL BE ABOUT -5 TO -6 DEGREES CELSIUS. HEAVY CLOUD COVER AND THE COOL NW FLOW WILL PREVENT HIGHS FROM GETTING MUCH HIGHER THAN THE LOW TO MIDDLE 40S. THERE WILL BE INCREASING CHANCES OF COLD RAIN SHOWERS AS THE UPPER LOW DEEPENS AND MOVES TO JUST NORTH OF KOOCHICHING COUNTY. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 342 AM CDT SUN APR 19 2015 A DEEP AREA OF LOW PRESSURE WILL SETTLE SOUTHWARD INTO THE LAKE SUPERIOR REGION MONDAY NIGHT AND TUESDAY. THE CLOSED H5 LOW WILL REACH WESTERN LAKE SUPERIOR BY TUESDAY AFTERNOON. NUMEROUS SHOWERS WILL ROTATE SOUTHWARD AROUND THE UPPER LOW...GENERALLY IN THE FORM OF SNOW SHOWERS AT NIGHT AND RAIN OR SNOW SHOWERS DURING THE DAY THROUGH THE MIDDLE OF THE WEEK. DEFINITELY COULD BE SOME SLUSHY ACCUMULATION AT TIMES...ESPECIALLY IN THE NORTH. WOULD NOT BE SURPRISED TO SEE A COUPLE EPISODES OF UP TO A COUPLE INCHES... FOLLOWED BY SOME PARTIAL TO FULL MELTING DURING THE DAY. THIS MASSIVE UPPER LEVEL TROUGH WILL EVENTUALLY LOSE ITS GRIP ON THE AREA FROM THE MIDDLE TO THE END OF THE WORK WEEK. THE GEM AND TO SOME EXTENT THE ECMWF ARE THE MOST AGGRESSIVE IN PUSHING THE UPPER TROUGH EASTWARD THROUGH THE END OF THE WEEK...WITH THE GEM BRINGING UPPER LEVEL RIDGING ALREADY INTO THE CWA BY 12Z FRIDAY. THE GFS IS MUCH SLOWER AND DEEPER WITH THE UPPER LEVEL LOW. STRONGLY FAVORING THE GEM/ECMWF SOLUTION...ESPECIALLY LATE IN THE WEEK AND INTO THE WEEKEND. HIGH TEMPERATURES WILL REMAIN ON THE COOL SIDE DURING THE WEEK...REACHING BACK INTO THE LOW TO MID 50S ON THE WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 656 AM CDT SUN APR 19 2015 A LARGE AREA OF LOW PRESSURE WILL CONTINUE TO MOVE NORTHEAST INTO THE NORTHLAND TODAY AND TONIGHT. ABUNDANT MOISTURE THROUGH THE PLAINS WILL CONTINUE TO BRING AREAS OF LIGHT RAIN TODAY INTO TONIGHT. CLOUD HEIGHTS ARE EXPECTED TO GRADUALLY DECREASE TO MVFR OR EVEN IFR DURING THE MORNING...AND REMAIN THAT WAY THROUGH THE AFTERNOON. SOME IMPROVEMENT IN CLOUD HEIGHTS WILL BE POSSIBLE FROM THE WEST...AS SOMEWHAT DRIER AIR PUSHES EASTWARD BEHIND A COLD FRONT. && .PRELIMINARY POINT TEMPS/POPS... DLH 49 34 44 29 / 80 30 30 60 INL 49 32 40 28 / 90 40 60 60 BRD 56 35 43 31 / 80 20 40 40 HYR 58 37 46 30 / 80 80 30 60 ASX 58 37 47 32 / 80 80 20 60 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ142>147. && $$ SHORT TERM...GROCHOCINSKI LONG TERM...DAP AVIATION...DAP
AREA FORECAST DISCUSSION
NWS DULUTH MN
342 AM CDT SUN APR 19 2015 .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 342 AM CDT SUN APR 19 2015 THE FOCUS REMAINS ON THE RAIN TODAY AND TONIGHT. REFINED THE PCPN CHANCES BY USING A BLEND OF THE RAP13 AND HRRR MODEL RUNS THROUGH THIS MORNING SINCE THE TWO MODELS SEEM TO BE DOING PRETTY WELL CAPTURING THE LOCATION OF THE CURRENT RAIN. DID NOT MAKE ANY DRAMATIC CHANGES TO RAINFALL. OVERALL...MUCH OF THE FORECAST AREA CAN EXPECT ABOUT 0.30 TO 0.75 INCHES OF RAINFALL THROUGH TONIGHT. AT 330 AM...AN AREA OF LOW PRESSURE WAS OVER THE BORDER BETWEEN SOUTH DAKOTA AND SW MINNESOTA. A FRONTAL BOUNDARY EXTENDED NORTHWARD TO ANOTHER AREA OF LOW PRESSURE IN SOUTHERN MANITOBA. THERE WAS AN UPPER LEVEL TROUGH OVER THE NORTHERN HIGH PLAINS AND SASKATCHEWAN/MANITOBA DIGGING AND DEEPENING TOWARDS THE NORTHERN PLAINS AND ONTARIO. A LARGE AREA OF RAIN WAS LIFTING TO NNE THROUGH THE SOUTHERN TWO THIRDS OF THE FORECAST AREA. THIS RAIN WAS ASSOCIATED WITH A BAND OF MID LEVEL FRONTOGENESIS AHEAD OF THE LOW NEAR THE SD/MN BORDER. THERE WAS ADDITIONAL RAIN IN EASTERN SOUTH DAKOTA AND NW MINNESOTA MOVING TO THE EAST IN THE WAKE OF THE TROUGH BOUNDARY AND AHEAD OF THE UPPER LEVEL TO THE WEST. THE NORTHLAND HAD CLOUDY SKIES WITH TEMPERATURES IN THE UPPER 30S TO MIDDLE 40S. THE NORTHLAND HAD LIGHT EASTERLY TO SOUTHEASTERLY WINDS. THIS MORNING...THE SURFACE LOW NEAR THE SD/MN BORDER WILL LIFT NE TO THE AITKIN AREA BY THIS AFTERNOON. THE SURFACE LOW IN SOUTHERN MANITOBA WILL DIG TO THE SE. THE RAIN OVER THE FORECAST AREA EARLY THIS MORNING WILL CONTINUE LIFTING TO THE NORTH WITH THE BAND OF MID LEVEL FRONTOGENESIS. PARTS OF THE NORTHERN FORECAST COULD PICK UP TO AROUND A HALF INCH OF RAIN THROUGH THIS MORNING. THE COLD FRONT IN NORTH DAKOTA WILL BEGIN TO MOVE INTO THE WESTERN FORECAST AREA LATE THIS MORNING. THIS AFTERNOON AND EVENING...THE TWO LOWS WILL GRADUALLY MERGE INTO ONE LOW OVER NW ONTARIO. CLOUDY AND COOL WEATHER IS EXPECTED WITH HIGHS RANGING FROM THE UPPER 40S OVER THE NORTH TO THE 50S OVER THE SOUTH. MOST OF THE AFTERNOON AND EVENING RAIN WILL BE OVER THE EASTERN FORECAST AREA AHEAD OF THE EASTWARD ADVANCING COLD FRONT. A DRY SLOT WILL MOVE INTO THE WESTERN FORECAST AREA...AND THERE COULD BE PARTIAL CLEARING IN THE SW FORECAST AREA. ALSO...A PROMINENT BAND OF LOW/MID LEVEL FRONTOGENESIS WILL SET UP OVER NW WISCONSIN THIS EVENING WHICH DEVELOP AND INTENSIFY A BAND OF RAIN OVER THAT AREA. THE UPPER LEVEL TROUGH OVER THE NORTHERN PLAINS AND SOUTH CENTRAL CANADA WILL DEEPEN AND DEVELOP INTO A WELL DEFINED UPPER LEVEL OVER SOUTHERN MANITOBA THIS AFTERNOON AND CONTINUE DEEPENING AS IT APPROACHES NORTHERN MANITOBA. LATER TONIGHT AND EARLY MONDAY...THE COLD FRONT WILL FINISH MOVING THROUGH THE FORECAST AREA. THE UPPER LEVEL LOW WILL CONTINUE DEEPENING OVER NW ONTARIO. THE LOW/MID LEVEL FRONTOGENETICAL BAND IN NW WISCONSIN SHOULD EXIT TO THE EAST BY AROUND DAWN. TEMPERATURES WILL DROP INTO THE MIDDLE AND LOWER 30S TONIGHT. THE SYNOPTIC LIFT FROM THE UPPER LEVEL LOW WILL LIKELY RESULT IN LIGHT RAIN AND SNOW MOVING INTO THE NW FORECAST AREA. LITTLE OF ANY SNOW ACCUMULATION IS EXPECTED SINCE MUCH OF IT SHOULD MELT...EITHER ON IMPACT OR LATER IN THE MORNING. MONDAY...IT WILL BE MUCH COOLER DAY WITH BLUSTERY NW WINDS. SUSTAINED WINDS OF 10 TO 20 MPH WILL DEVELOP BY THE AFTERNOON...AND THERE COULD BE GUSTS UP TO 30 MPH. THE 850 HPA TEMPERATURES WILL BE ABOUT -5 TO -6 DEGREES CELSIUS. HEAVY CLOUD COVER AND THE COOL NW FLOW WILL PREVENT HIGHS FROM GETTING MUCH HIGHER THAN THE LOW TO MIDDLE 40S. THERE WILL BE INCREASING CHANCES OF COLD RAIN SHOWERS AS THE UPPER LOW DEEPENS AND MOVES TO JUST NORTH OF KOOCHICHING COUNTY. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 342 AM CDT SUN APR 19 2015 A DEEP AREA OF LOW PRESSURE WILL SETTLE SOUTHWARD INTO THE LAKE SUPERIOR REGION MONDAY NIGHT AND TUESDAY. THE CLOSED H5 LOW WILL REACH WESTERN LAKE SUPERIOR BY TUESDAY AFTERNOON. NUMEROUS SHOWERS WILL ROTATE SOUTHWARD AROUND THE UPPER LOW...GENERALLY IN THE FORM OF SNOW SHOWERS AT NIGHT AND RAIN OR SNOW SHOWERS DURING THE DAY THROUGH THE MIDDLE OF THE WEEK. DEFINITELY COULD BE SOME SLUSHY ACCUMULATION AT TIMES...ESPECIALLY IN THE NORTH. WOULD NOT BE SURPRISED TO SEE A COUPLE EPISODES OF UP TO A COUPLE INCHES... FOLLOWED BY SOME PARTIAL TO FULL MELTING DURING THE DAY. THIS MASSIVE UPPER LEVEL TROUGH WILL EVENTUALLY LOSE ITS GRIP ON THE AREA FROM THE MIDDLE TO THE END OF THE WORK WEEK. THE GEM AND TO SOME EXTENT THE ECMWF ARE THE MOST AGGRESSIVE IN PUSHING THE UPPER TROUGH EASTWARD THROUGH THE END OF THE WEEK...WITH THE GEM BRINGING UPPER LEVEL RIDGING ALREADY INTO THE CWA BY 12Z FRIDAY. THE GFS IS MUCH SLOWER AND DEEPER WITH THE UPPER LEVEL LOW. STRONGLY FAVORING THE GEM/ECMWF SOLUTION...ESPECIALLY LATE IN THE WEEK AND INTO THE WEEKEND. HIGH TEMPERATURES WILL REMAIN ON THE COOL SIDE DURING THE WEEK...REACHING BACK INTO THE LOW TO MID 50S ON THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 101 AM CDT SUN APR 19 2015 AN AREA OF LOW PRESSURE WILL SPREAD GRADUALLY LOWERING CLOUDS AND RAINFALL INTO THE AREA FROM THE SOUTHWEST THROUGH 10Z...WITH CEILINGS SLOWLY LOWERING TO IFR WITH VISIBILITIES TO MVFR IN LIGHT RAIN. THIS WILL CONTINUE THROUGH APPROXIMATELY 18Z BEFORE SLOWLY DIMINISHING AGAIN FROM SOUTHWEST TO NORTHEAST. CEILINGS EXPECTED TO REMAIN MVFR-IFR UNTIL AFTER LOW PASSAGE AND WINDS TURN TO NORTHWEST...ALLOWING CEILINGS AND VISIBILITIES TO GRADUALLY RETURN TO MVFR...THEN VFR BY 02Z THIS EVENING. && .PRELIMINARY POINT TEMPS/POPS... DLH 49 36 42 30 / 90 40 60 50 INL 49 32 40 27 / 100 50 70 60 BRD 55 36 42 30 / 90 20 60 40 HYR 56 37 44 31 / 90 60 50 50 ASX 56 38 45 32 / 80 60 50 60 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY UNTIL 10 AM CDT THIS MORNING FOR LSZ142>147. && $$ SHORT TERM...GROCHOCINSKI LONG TERM...DAP AVIATION...DAP
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1239 PM CDT Sun Apr 19 2015 .UPDATE... Issued at 723 AM CDT SUN APR 19 2015 Made major adjustments to the forecast. Lowered PoPs considerably for the rest of the morning south and west of a h7 vorticity lobe that defines the back edge of showers over northern and into central MO...roughly along an arc from St. Joseph to Sedalia. Trend of the HRRR, RUC and even the NAM supports the above scenario. Convective cluster over north central OK may graze the far southern counties this afternoon so likely PoPs this area seems reasonable. So, for a good portion of today many areas will see little in the way of measurable rainfall. Still believe we`ll see a band of stratiform type rain tied to the post-frontal baroclinic zone/deformation zone that will slide ese across the CWA from late afternoon through this evening. && .SHORT TERM...(Today through Tuesday) Issued at 407 AM CDT SUN APR 19 2015 Today - Tonight: Today`s weather will be governed by the transition of an upper level closed low to an open wave. Latest water vapor satellite imagery shows the closed upper low has now shifted east into west central KS early this morning. A shortwave trough digging into the Northern High Plains will push this feature and its associated convection through the CWA today with the rain ending from west to east this evening. Scattered showers and isolated thunderstorms will accompany a couple mid level vorticity lobes as they rotate northeast across KS and MO. No severe storms are expected today as less than impressive MUCAPEs in the 400-800 J/kg range and bulk shear values around 25kts will limit the strength of the storms. Like yesterday a few cells could produce small hail during peak heating. Temperatures will again be negatively impacted by the convection and cloud cover. A more organized band of stratiform rain tied to post-frontal frontogenesis and an elongated deformation zone overspreads the region during the evening hours. Monday - Tuesday: The Northern Plains upper trough will gradually sharpen south and shift east on Monday with strong subsidence spilling southeast on the backside of the trough. Clearing skies will help offset cold air advection yielding slightly below average temperatures both days. The operational models are showing similar weak signals on Tuesday that we`ll need to start considering the chance of some shower activity. The models generate a series of weak strung out vorticity lobes stretching southeast from NE through MO. Moisture will be the main limiting factor so if any rain forms it will be light and scattered. .LONG TERM...(Wednesday through Saturday) Issued at 407 AM CDT SUN APR 19 2015 Slightly below normal temperatures will stretch through the latter half of the week as deep low pressure very slowly transitions SE across the Great Lakes, and northwest flow aloft ushers cooler temperatures into the region. At the same time a surface boundary will drift southward through Wednesday, leaving the forecast area in north to northeast surface flow and also helping to keep highs in the lower to mid 60s. A few light showers and isolated storms are possible over the southern tier of the CWA Wednesday and Wednesday night as the front heads south, then a period of drier conditions is expected on the north side of the boundary Thursday. Southerly surface flow will eventually return by the end of the work week ahead of a shortwave trough that will eject out of the desert southwest and into the Plains by Friday. Widely scattered showers and storms are possible as early as Friday afternoon, but are more likely Friday night as the upper trough passes over the CWA. Timing of this system is still a bit uncertain, and the probability of any embedded storms will depend on how quickly southerly flow and low- level moisture return to the region ahead of the shortwave trough. At this time, the southern track of the associated surface low and the environment in place ahead of the system suggests that the potential for strong storms is very low. The clouds and any rain associated with the system will keep temperatures down despite the transition to southerly flow, so have kept highs mainly in the lower 60s through the end of the work week and into the weekend. Current model trends show the wet weather clearing out by Saturday evening and a dry Sunday, but will have to watch the potential for Friday`s system to slow down and impact the coming weekend. && .AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon) Issued at 1237 PM CDT SUN APR 19 2015 Rain will stay out of the terminals for the next few hours, but by this evening rain, with some embedded thunder will move through the terminals. Expect the bulk of the rainy activity to only last a couple hours, with perhaps a few lingering hours of low ceilings and drizzle or very light rain. Expect winds to be gusty all night, but they should really pick up out of the NW by mid morning on Monday. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ UPDATE...MJ SHORT TERM...MJ LONG TERM...Laflin AVIATION...Leighton
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
727 AM CDT Sun Apr 19 2015 .UPDATE... Issued at 723 AM CDT SUN APR 19 2015 Made major adjustments to the forecast. Lowered PoPs considerably for the rest of the morning south and west of a h7 vorticity lobe that defines the back edge of showers over northern and into central MO...roughly along an arc from St. Joseph to Sedalia. Trend of the HRRR, RUC and even the NAM supports the above scenario. Convective cluster over north central OK may graze the far southern counties this afternoon so likely PoPs this area seems reasonable. So, for a good portion of today many areas will see little in the way of measurable rainfall. Still believe we`ll see a band of stratiform type rain tied to the post-frontal baroclinic zone/deformation zone that will slide ese across the CWA from late afternoon through this evening. && .SHORT TERM...(Today through Tuesday) Issued at 407 AM CDT SUN APR 19 2015 Today - Tonight: Today`s weather will be governed by the transition of an upper level closed low to an open wave. Latest water vapor satellite imagery shows the closed upper low has now shifted east into west central KS early this morning. A shortwave trough digging into the Northern High Plains will push this feature and its associated convection through the CWA today with the rain ending from west to east this evening. Scattered showers and isolated thunderstorms will accompany a couple mid level vorticity lobes as they rotate northeast across KS and MO. No severe storms are expected today as less than impressive MUCAPEs in the 400-800 J/kg range and bulk shear values around 25kts will limit the strength of the storms. Like yesterday a few cells could produce small hail during peak heating. Temperatures will again be negatively impacted by the convection and cloud cover. A more organized band of stratiform rain tied to post-frontal frontogenesis and an elongated deformation zone overspreads the region during the evening hours. Monday - Tuesday: The Northern Plains upper trough will gradually sharpen south and shift east on Monday with strong subsidence spilling southeast on the backside of the trough. Clearing skies will help offset cold air advection yielding slightly below average temperatures both days. The operational models are showing similar weak signals on Tuesday that we`ll need to start considering the chance of some shower activity. The models generate a series of weak strung out vorticity lobes stretching southeast from NE through MO. Moisture will be the main limiting factor so if any rain forms it will be light and scattered. .LONG TERM...(Wednesday through Saturday) Issued at 407 AM CDT SUN APR 19 2015 Slightly below normal temperatures will stretch through the latter half of the week as deep low pressure very slowly transitions SE across the Great Lakes, and northwest flow aloft ushers cooler temperatures into the region. At the same time a surface boundary will drift southward through Wednesday, leaving the forecast area in north to northeast surface flow and also helping to keep highs in the lower to mid 60s. A few light showers and isolated storms are possible over the southern tier of the CWA Wednesday and Wednesday night as the front heads south, then a period of drier conditions is expected on the north side of the boundary Thursday. Southerly surface flow will eventually return by the end of the work week ahead of a shortwave trough that will eject out of the desert southwest and into the Plains by Friday. Widely scattered showers and storms are possible as early as Friday afternoon, but are more likely Friday night as the upper trough passes over the CWA. Timing of this system is still a bit uncertain, and the probability of any embedded storms will depend on how quickly southerly flow and low- level moisture return to the region ahead of the shortwave trough. At this time, the southern track of the associated surface low and the environment in place ahead of the system suggests that the potential for strong storms is very low. The clouds and any rain associated with the system will keep temperatures down despite the transition to southerly flow, so have kept highs mainly in the lower 60s through the end of the work week and into the weekend. Current model trends show the wet weather clearing out by Saturday evening and a dry Sunday, but will have to watch the potential for Friday`s system to slow down and impact the coming weekend. && .AVIATION...(For the 12Z TAFS through 12Z Monday Morning) Issued at 635 AM CDT SUN APR 19 2015 Scattered showers and a few storms lifting north through northern MO may define the last of the rain till late this afternoon and evening when deformation band of stratiform type rain moves in. The onset of gusty northwest winds will likely signal when this band will move in with its MVFR ceilings. Till then think much of the day will only see spotty hit/miss type showers. Thunderstorm risk looks minimal. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ UPDATE...MJ SHORT TERM...MJ LONG TERM...Laflin AVIATION...MJ
AREA FORECAST DISCUSSION...UPDATED
NWS SPRINGFIELD MO
1201 AM CDT Sun Apr 19 2015 ...Updated Aviation Section... .UPDATE... Issued at 703 PM CDT SAT APR 18 2015 Forecast will be updated shortly to account for short term trends from satellite/radar as well as to account for expected convective trends heading into the overnight hours. Over the past few hours, we have seen clearing across western portions of the area. This clearing will likely be short lived as mid/high level clouds increase from the west from convective exhaust. That said, this area did see a soaking rain this morning and dewpoints remain relatively high compared to expected lows. As a result, will include a mention of patchy fog and keep an eye on localized dense fog potential in places where skies can remain clear for a longer period of time. In addition, PoPs have been updated for the next 12 or so hours. The western half of the area will likely see little in the way of rain chances this evening. Chances over the eastern half look to remain in the solid chance range giving on again/off again showers and isolated thunder. HRRR and other short range models continue to indicate rain chances increasing across south central Missouri and the eastern Ozarks from late this evening into the overnight hours. In addition, remnant convection from KS/OK complexes will enter from the west, with rain chances steadily increasing across extreme southeastern Kansas and western Missouri. Interestingly, the Highway 65 corridor will likely be between these two areas of activity and PoPs are lowest in this area for tonight. Taking a peak at tomorrow`s severe weather potential. There remains some question as to just how much instability we will be able to generate as decaying convection continues to spread in from the west during the morning hours. The main upper trough will not arrive until later in the day, bringing and increase in deep layer shear. However, models struggle to bring much more that 500-1000 J/kg of most unstable CAPE into the southern half of the area. By far the better chances for severe convection will be to our south and southeast. Obviously this is close enough to keep a close eye on trends and we will see what the 00z suite of models have in store for the area. && .SHORT TERM...(This Evening through Sunday Night) Issued at 315 PM CDT SAT APR 18 2015 The coverage of showers and thunderstorms continued to decrease into the afternoon. However a band of scattered showers and storms persisted along a 925-850 MB convergence axis that stretched north to south east of the Highway 65 corridor and in advance of a mid level vorticity lobe lifting northeast across the area. Expect convection through early evening to be focused along and ahead of these features across south central Missouri. This 925-850 MB convergence axis may become the focus for additional development later tonight across the eastern Ozarks as another vorticity lobe lifts northeast toward southeastern Missouri. Coverage of precipitation will remain more isolated elsewhere much of tonight. However there may be increase in convection from the west into southeastern Kansas into far southwest late tonight as convection across the Plains shifts eastward. The closed upper level low now over eastern Colorado will open up and track eastward toward Missouri on Sunday. Expect the coverage of convection to increase Sunday as synoptic scale lift increases with the aide of an increasingly diffluent upper flow and the approach of vorticity maxima. Deep layer shear will increase Sunday as the mid level flow strengthens and lapse rates steepen as temperatures aloft cool in response to the approaching upper level trough. The question is the extent of instability that will develop. The potential for ongoing convection and cloud cover may limit surface heating and resulting instability. However if sufficient instability can be realized then ingredients would be in place for at least a few severe storms. At this time the greatest potential for strong to severe storms will be across far southern Missouri or generally along and south of Interstate 44. The risk for severe weather could decrease or increase depending on the amount of destabilization. The primary risks with any severe storms that can develop would damaging winds and large hail. With some areas already receiving moderate to heavy rainfall the past couple of days...the risk for localized flooding will have to be monitored particularly across far southwestern Missouri. Showers and some thunder will linger into Sunday night as the upper level trough and associated cold front track across the area. .LONG TERM...(Monday through Saturday) Issued at 315 PM CDT SAT APR 18 2015 Much cooler weather will prevail heading into early next week as an upper level trough digs into the Great Lakes and maintains a northwesterly flow aloft across the region. This cooler weather will persist most of next week. Weather conditions could also be rather unsettled as disturbances slide southeastward around the periphery of the upper trough. This will bring intervals clouds and the possibility of showers and thunderstorms at times mid through late week. However this activity is expected to be spotty in nature. Temperatures could fall into the upper 30s Monday night. Frost is not expected at this time but this potential should be monitored. && .AVIATION...(For the 06Z TAFS through 06Z Sunday Night) Issued at 1201 AM CDT SUN APR 19 2015 Challenging forecast for area aerodromes as convection will fester around the region the rest of tonight, and regenerate Sunday afternoon. Decaying bands of showers/storms will attempt to enter from the west in the coming hours, however a lack of instability will likely result in this activity losing its punch and gradually dissipating as it moves through the JLN aerodrome. Earlier clearing at SGF/BBG is being replaced by mid/high level clouds. There is patchy ground fog around, but this may not become too widespread. Bouts of MVFR visibility are expected, with an outside chance of IFR at BBG. Main storm system will move into area Sunday afternoon/evening. Another round of showers/storms will be associated with this system, which will begin to exit to the east by the end of the TAF cycle. Winds will be light into the daylight hours of Sunday morning, becoming southwesterly during the day and shift to the northwest heading into the evening. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ UPDATE...Gagan SHORT TERM...Foster LONG TERM...Foster AVIATION...Gagan
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
833 PM MDT MON APR 20 2015 .UPDATE... NO CHANGES NEED TO THE GOING FORECAST. RADAR SHOWED WEAK ECHOES OVER NE MT...AHEAD OF THE BACK DOOR COLD FRONT THAT WAS OVER S CENTRAL SASKATCHEWAN INTO NW ND...THIS EVENING. THE ECHOES APPEARED TO BE MID CLOUD COVER BASED ON SURFACE OBSERVATIONS THAT HAD TEMPERATURE/DEWPOINT SPREADS ON THE ORDER OF 30 DEGREES. SATELLITE SHOWED THE CLOUDS OVER NE MT AS WELL AS OTHER MID LEVEL CLOUDS OVER THE FORECAST AREA. WEBCAMS SHOWED A COUPLE OF SHOWERS EARLIER IN THE EVENING...BUT THESE HAVE DISSIPATED WITH LOSS OF SOLAR INSOLATION. THE BACK DOOR FRONT WAS FORECAST TO MOVE THROUGH NE MT OVERNIGHT. NEW WRF AND LAST COUPLE OF HRRR RUNS WERE DRY OVERNIGHT. THE DRY FORECAST WAS IN GOOD SHAPE BASED ON THE ABOVE. WEAK ENERGY SPILLING OVER THE UPPER RIDGE ANCHORED OVER THE PACIFIC NW INTO W CANADA...WILL SUPPORT PARTLY CLOUDY SKIES ACROSS THE AREA OVERNIGHT. LIFT AHEAD OF THE BACK DOOR FRONT WILL SUPPORT MID CLOUDS OVER THE AREA AHEAD AS WELL. SKY GRIDS REFLECTED THIS WELL. 850 MB TEMPERATURES WILL REMAIN FAIRLY STEADY AROUND +8 DEGREES C OVERNIGHT AND FORECAST AREA WILL BE IN A PREFRONTAL ENVIRONMENT. BASED ON THE ABOVE...AND RECENT TRENDS OF LOWS VERIFYING AT OR BELOW GUIDANCE...THE FORECAST MINS LOOKED REASONABLE. RH AND WINDS WERE ALSO ON TRACK. DRY LOW-LEVELS WILL LIMIT SHOWERS WITH THE FRONT ON TUE. GOING FORECAST HAD POPS RESTRICTED TO THE HIGHER ELEVATIONS WHICH SEEMED REASONABLE. ARTHUR && .SHORT TERM...VALID FOR TUE AND WED... THE SHORT TERM IS DOMINATED BY THE RIDGE OVER THE INTERMOUNTAIN WEST SLOWLY SHIFTING TO THE EAST. THIS WILL KEEP THE AREA MAINLY IN CYCLONIC NORTHWEST FLOW. SEVERAL WEAK BANDS OF ENERGY WILL MOVE THROUGH THE AREA...MAINLY OVER THE MOUNTAINS. HAVE CONTINUED THE SLIGHT CHANCES OF PRECIP OVER THE MOUNTAINS THROUGH THE PERIOD. TOMORROW WILL SEE WARMER TEMPERATURES APPROACHING 70 DEGREES. WINDS WILL BEGIN TO SHIFT MORE EASTERLY TOMORROW AFTERNOON WHICH WILL HELP TO BRING MORE MOISTURE INTO THE AREA. WINDS WILL BE OUT OF THE EAST THROUGH MUCH OF THE DAY ON WEDNESDAY...SO EXPECTING RAIN CHANCES TO BEGIN TO INCREASE...WITH CHANCES OVER THE MOUNTAINS AND FOOTHILLS...AND A SLIGHT CHANCE OUT ONTO THE PLAINS. REIMER .LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON... THE FORECAST AREA WILL STILL BE IN A BLOCKING PATTERN THROUGH THE FORECAST PERIOD. THIS BLOCKING PATTERN INVOLVES A DEEP UPPER LOW OVER THE GREAT LAKES AREA AND A DEEPENING TROUGH OFF THE PACIFIC NORTHWEST. MONTANA AND NORTHERN WYOMING WILL BE IN BETWEEN THESE SYSTEMS AND SUBJECT TO A WEAK RIDGING PATTERN ON THURSDAY. THIS WEAK RIDGING BREAKS DOWN ON FRIDAY AS THE EASTERN TROUGH SHIFTS EAST A BIT. THIS BREAK DOWN WILL ALLOW WEAK ENERGY TO KICK OUT OF THE WESTERN TROUGH AND SLIDE ACROSS THE FORECAST AREA FRIDAY THROUGH NEXT WEEKEND. EASTERLY LOW LEVEL FLOW WILL KEEP SOME LOW LEVEL MOISTURE AVAILABLE AND WILL THUS KEEP POPS GOING. THE BEST CHANCE OF SHOWERS SHOULD BE SATURDAY AS A DEEP TROUGH AND SURFACE LOW MOVES ACROSS THE AREA. LOW LEVEL EASTERLY WINDS WILL KEEP TEMPERATURES TO SLIGHTLY ABOVE SEASONAL VALUES. TWH && .AVIATION... VFR CONDITIONS WILL BE OVER THE AREA TONIGHT THROUGH TUE EVENING. LOCALIZED MOUNTAIN OBSCURATIONS WILL OCCUR THROUGH TUE EVENING. ARTHUR && .PRELIMINARY POINT TEMP/POPS... TUE WED THU FRI SAT SUN MON ----------------------------------------------------------- BIL 038/066 040/072 042/070 041/065 043/063 040/067 042/068 01/B 10/B 12/W 22/W 33/W 32/W 21/B LVM 034/069 037/074 038/070 038/063 038/062 035/064 037/066 01/B 21/B 33/W 34/W 43/W 32/W 22/W HDN 034/067 036/073 038/072 037/066 038/066 036/070 036/071 01/B 10/B 12/W 22/W 33/W 32/W 21/B MLS 032/063 034/069 036/068 038/066 039/066 038/068 038/069 00/U 10/B 01/B 22/W 33/W 32/W 21/B 4BQ 031/064 033/069 036/068 038/064 039/064 037/068 036/070 00/B 10/B 01/B 23/W 33/W 42/W 21/B BHK 028/057 029/063 031/063 034/062 035/061 034/066 033/064 00/U 10/B 00/N 23/W 33/W 42/W 21/B SHR 028/064 035/069 037/069 037/062 038/063 036/065 036/068 01/B 10/B 13/W 33/W 34/W 32/W 21/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
129 PM CDT SUN APR 19 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 313 AM CDT SUN APR 19 2015 THE UPPER LOW WHICH PRODUCED UP TO 52 INCHES OF SNOW IN COLORADO HAS DRIFTED EAST INTO WRN KS THIS MORNING. RAIN AND THUNDERSTORMS ARE FALLING UNDER THE LOW. A DEFORMATION ZONE OF RAIN AND ISOLATED THUNDERSTORMS IS WEAKENING ACROSS NCNTL AND SWRN NEB THIS MORNING. THE MODELS DRAG THIS AREA OF RAIN SOUTH AND OUT OF THE FORECAST AREA BY 15Z-18Z. A STRONG COLD FRONT WITH SCATTERED SHOWERS WILL DROP THROUGH THE FCST AREA THIS MORNING SETTING UP A WINDY AND COOL DAY. NORTHWEST WINDS WILL INCREASE TO 20 TO 30 MPH WITH GUSTS TO 40 MPH. THESE WINDS ARE ALREADY UNDERWAY IN THE PANHANDLE. THE STRONG WINDS BEND AROUND THE BLACK HILLS PRODUCING CONVERGENCE ACROSS SHERIDAN AND CHERRY COUNTIES. THE HRRR SHOWS SPRINKLES DEVELOPING BUT GIVEN THE VERY DRY AIR MOVING IN WITH DEW POINTS FALLING INTO THE 20S BY NOON...NO MEASURABLE RAINFALL WOULD BE EXPECTED. HIGHS TODAY RISE INTO THE 50S WITH PARTLY CLOUDY SKIES. THE MODELS ARE BRINGING IN COLD AIR ALOFT FROM AN UPPER LEVEL ACROSS MANITOBA. THE RESULT IS H700MB TEMPERATURES FALL TO AROUND -10C BY 21Z. SOME SUN IS EXPECTED BUT SKIES WOULD LIKELY CLOUD UP IN THE AFTERNOON WITH THE COLD AIR ALOFT. TONIGHT...THE UPPER LOW ACROSS WRN KS WILL LIFT INTO THE UPPER MIDWEST AND BE ABSORBED THE A DISTURBANCE ACROSS WRN ONTARIO TONIGHT. THIS WILL PULL PACIFIC HIGH PRESSURE INTO THE FCST AREA. GENERALLY CLEAR SKIES ARE EXPECTED WITH LOWS IN THE 20S TO LOWER 30S. WINDS STAY UP AT 10 TO 15 MPH NEAR ONEILL WHERE THE WARMER LOWS ARE EXPECTED. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 313 AM CDT SUN APR 19 2015 MONDAY INTO MID WEEK WILL SEE THE LOW PRESSURE SYSTEMS TO THE NORTHEAST AND EAST MERGE NEAR/NORTH OF THE GREAT LAKES. MEANWHILE NORTHWEST FLOW DOMINATES THE HIGH PLAINS AND AN UPPER LEVEL TROUGH DIGS ACROSS THE PACIFIC COAST. THE LOW PRESSURE SYSTEM TO THE NORTHEAST WILL DRAW SOME COOL AND DRY CANADIAN AIR TO THE REGION. TEMPERATURES WILL BE THE MAIN FOCUS THROUGH MID WEEK AND ARE TRICKY. THE DRY AIR MOVING SOUTH WILL ALLOW FOR DEW POINTS TO FALL INTO THE TEENS AND 20S...HOWEVER WITH THE RECENT HEAVY RAIN...THOUGHT MODELS ARE A TAD TO DRY SO DID RAISE SLIGHTLY BUT COULD SEE THEM BEING HIGHER...ESPECIALLY BY WED. SKIES WILL GENERALLY BE MOSTLY CLEAR...ALTHOUGH A COUPLE WEAK CLIPPERS MAY BRING A BRIEF INCREASE OF CLOUDS. WITH MOSTLY CLEAR SKIES AND DRY AIR TEMPS TO LIKELY FALL TO OR BELOW THE FREEZING MARK FOR THE FIRST FEW DAYS OF THE WEEK...UNLESS BL MOISTURE ENDS UP BEING MORE THAN EXPECTED FROM RECENT RAIN. MEANWHILE AFTERNOON SUN WILL HELP OFFSET THE COOL CONDITIONS AND BE ABLE TO AID IN MIXING THE BL...SEASONAL HIGHS /50S AND 60S/ EXPECTED. ONE CONCERN WITH HIGHS IS THE COOL TEMPS ALOFT...WHICH MAY RESULT IN SOME AFTERNOON CLOUDS DUE TO STEEP LAPSE RATES DEVELOPING. FAIRLY DRY AIR AT THE SFC SO NOTHING EXPECTED TO REACH THE GROUND. BY THE END OF THE WEEK THE WEST COAST TROUGH WILL BECOME AN OPEN WAVE CROSSING THE DESERT SW/4 CORNERS. A TRANSITION FROM NW TO SW FLOW WILL BRING A RETURN FOR WET WEATHER. MODELS NOT IN THE BEST OF AGREEMENT ON TIMING...BUT DO PUSH THE WAVE ONTO THE SOUTHERN/CENTRAL PLAINS BY THE WEEKEND. SHOULD SEE A BRIEF WINDOW OF RETURN MOIST SOUTHEASTERLY FLOW AHEAD OF THE WAVE. THIS TRACK AND THE INCREASE OF MOISTURE WILL FAVOR A CHANCE FOR RAIN...ALBEIT BETTER FOR SOUTHERN ZONES THAN NORTHERN ZONES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 116 PM CDT SUN APR 19 2015 THE LARGE SLOW MOVING STORM SYSTEM RESPONSIBLE FOR THE WEATHER OF LATE WILL CONTINUE TO MOVE AWAY FROM THE AREA. VFR CONDITIONS WILL BE THE RULE...WITH GUSTY NORTHWEST WINDS UP TO 35 KTS THIS AFTERNOON. WINDS WILL DIMINISH TONIGHT...BUT INCREASE ONCE AGAIN MONDAY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...TAYLOR
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
620 AM CDT SUN APR 19 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 313 AM CDT SUN APR 19 2015 THE UPPER LOW WHICH PRODUCED UP TO 52 INCHES OF SNOW IN COLORADO HAS DRIFTED EAST INTO WRN KS THIS MORNING. RAIN AND THUNDERSTORMS ARE FALLING UNDER THE LOW. A DEFORMATION ZONE OF RAIN AND ISOLATED THUNDERSTORMS IS WEAKENING ACROSS NCNTL AND SWRN NEB THIS MORNING. THE MODELS DRAG THIS AREA OF RAIN SOUTH AND OUT OF THE FORECAST AREA BY 15Z-18Z. A STRONG COLD FRONT WITH SCATTERED SHOWERS WILL DROP THROUGH THE FCST AREA THIS MORNING SETTING UP A WINDY AND COOL DAY. NORTHWEST WINDS WILL INCREASE TO 20 TO 30 MPH WITH GUSTS TO 40 MPH. THESE WINDS ARE ALREADY UNDERWAY IN THE PANHANDLE. THE STRONG WINDS BEND AROUND THE BLACK HILLS PRODUCING CONVERGENCE ACROSS SHERIDAN AND CHERRY COUNTIES. THE HRRR SHOWS SPRINKLES DEVELOPING BUT GIVEN THE VERY DRY AIR MOVING IN WITH DEW POINTS FALLING INTO THE 20S BY NOON...NO MEASURABLE RAINFALL WOULD BE EXPECTED. HIGHS TODAY RISE INTO THE 50S WITH PARTLY CLOUDY SKIES. THE MODELS ARE BRINGING IN COLD AIR ALOFT FROM AN UPPER LEVEL ACROSS MANITOBA. THE RESULT IS H700MB TEMPERATURES FALL TO AROUND -10C BY 21Z. SOME SUN IS EXPECTED BUT SKIES WOULD LIKELY CLOUD UP IN THE AFTERNOON WITH THE COLD AIR ALOFT. TONIGHT...THE UPPER LOW ACROSS WRN KS WILL LIFT INTO THE UPPER MIDWEST AND BE ABSORBED THE A DISTURBANCE ACROSS WRN ONTARIO TONIGHT. THIS WILL PULL PACIFIC HIGH PRESSURE INTO THE FCST AREA. GENERALLY CLEAR SKIES ARE EXPECTED WITH LOWS IN THE 20S TO LOWER 30S. WINDS STAY UP AT 10 TO 15 MPH NEAR ONEILL WHERE THE WARMER LOWS ARE EXPECTED. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 313 AM CDT SUN APR 19 2015 MONDAY INTO MID WEEK WILL SEE THE LOW PRESSURE SYSTEMS TO THE NORTHEAST AND EAST MERGE NEAR/NORTH OF THE GREAT LAKES. MEANWHILE NORTHWEST FLOW DOMINATES THE HIGH PLAINS AND AN UPPER LEVEL TROUGH DIGS ACROSS THE PACIFIC COAST. THE LOW PRESSURE SYSTEM TO THE NORTHEAST WILL DRAW SOME COOL AND DRY CANADIAN AIR TO THE REGION. TEMPERATURES WILL BE THE MAIN FOCUS THROUGH MID WEEK AND ARE TRICKY. THE DRY AIR MOVING SOUTH WILL ALLOW FOR DEW POINTS TO FALL INTO THE TEENS AND 20S...HOWEVER WITH THE RECENT HEAVY RAIN...THOUGHT MODELS ARE A TAD TO DRY SO DID RAISE SLIGHTLY BUT COULD SEE THEM BEING HIGHER...ESPECIALLY BY WED. SKIES WILL GENERALLY BE MOSTLY CLEAR...ALTHOUGH A COUPLE WEAK CLIPPERS MAY BRING A BRIEF INCREASE OF CLOUDS. WITH MOSTLY CLEAR SKIES AND DRY AIR TEMPS TO LIKELY FALL TO OR BELOW THE FREEZING MARK FOR THE FIRST FEW DAYS OF THE WEEK...UNLESS BL MOISTURE ENDS UP BEING MORE THAN EXPECTED FROM RECENT RAIN. MEANWHILE AFTERNOON SUN WILL HELP OFFSET THE COOL CONDITIONS AND BE ABLE TO AID IN MIXING THE BL...SEASONAL HIGHS /50S AND 60S/ EXPECTED. ONE CONCERN WITH HIGHS IS THE COOL TEMPS ALOFT...WHICH MAY RESULT IN SOME AFTERNOON CLOUDS DUE TO STEEP LAPSE RATES DEVELOPING. FAIRLY DRY AIR AT THE SFC SO NOTHING EXPECTED TO REACH THE GROUND. BY THE END OF THE WEEK THE WEST COAST TROUGH WILL BECOME AN OPEN WAVE CROSSING THE DESERT SW/4 CORNERS. A TRANSITION FROM NW TO SW FLOW WILL BRING A RETURN FOR WET WEATHER. MODELS NOT IN THE BEST OF AGREEMENT ON TIMING...BUT DO PUSH THE WAVE ONTO THE SOUTHERN/CENTRAL PLAINS BY THE WEEKEND. SHOULD SEE A BRIEF WINDOW OF RETURN MOIST SOUTHEASTERLY FLOW AHEAD OF THE WAVE. THIS TRACK AND THE INCREASE OF MOISTURE WILL FAVOR A CHANCE FOR RAIN...ALBEIT BETTER FOR SOUTHERN ZONES THAN NORTHERN ZONES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 620 AM CDT SUN APR 19 2015 SATELLITE SUGGESTS THE DEFROMATION ZONE CAUSING MVFR CIGS/-RA MAY HAVE STALLED ACROSS SOUTHERN NEBRASKA. A COLD FRONT IS RACING SOUTH WHICH SHOULD DRY THIS AIR OUT ENDING THE RAIN AND LOW CIGS. THIS SUGGESTS VFR WOULD BE WIDESPREAD THROUGHOUT THE FCST AREA BY 15Z-18Z. VFR IS EXPECTED ALL AREAS THEREAFTER. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
314 AM CDT SUN APR 19 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 313 AM CDT SUN APR 19 2015 THE UPPER LOW WHICH PRODUCED UP TO 52 INCHES OF SNOW IN COLORADO HAS DRIFTED EAST INTO WRN KS THIS MORNING. RAIN AND THUNDERSTORMS ARE FALLING UNDER THE LOW. A DEFORMATION ZONE OF RAIN AND ISOLATED THUNDERSTORMS IS WEAKENING ACROSS NCNTL AND SWRN NEB THIS MORNING. THE MODELS DRAG THIS AREA OF RAIN SOUTH AND OUT OF THE FORECAST AREA BY 15Z-18Z. A STRONG COLD FRONT WITH SCATTERED SHOWERS WILL DROP THROUGH THE FCST AREA THIS MORNING SETTING UP A WINDY AND COOL DAY. NORTHWEST WINDS WILL INCREASE TO 20 TO 30 MPH WITH GUSTS TO 40 MPH. THESE WINDS ARE ALREADY UNDERWAY IN THE PANHANDLE. THE STRONG WINDS BEND AROUND THE BLACK HILLS PRODUCING CONVERGENCE ACROSS SHERIDAN AND CHERRY COUNTIES. THE HRRR SHOWS SPRINKLES DEVELOPING BUT GIVEN THE VERY DRY AIR MOVING IN WITH DEW POINTS FALLING INTO THE 20S BY NOON...NO MEASURABLE RAINFALL WOULD BE EXPECTED. HIGHS TODAY RISE INTO THE 50S WITH PARTLY CLOUDY SKIES. THE MODELS ARE BRINGING IN COLD AIR ALOFT FROM AN UPPER LEVEL ACROSS MANITOBA. THE RESULT IS H700MB TEMPERATURES FALL TO AROUND -10C BY 21Z. SOME SUN IS EXPECTED BUT SKIES WOULD LIKELY CLOUD UP IN THE AFTERNOON WITH THE COLD AIR ALOFT. TONIGHT...THE UPPER LOW ACROSS WRN KS WILL LIFT INTO THE UPPER MIDWEST AND BE ABSORBED THE A DISTURBANCE ACROSS WRN ONTARIO TONIGHT. THIS WILL PULL PACIFIC HIGH PRESSURE INTO THE FCST AREA. GENERALLY CLEAR SKIES ARE EXPECTED WITH LOWS IN THE 20S TO LOWER 30S. WINDS STAY UP AT 10 TO 15 MPH NEAR ONEILL WHERE THE WARMER LOWS ARE EXPECTED. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 313 AM CDT SUN APR 19 2015 MONDAY INTO MID WEEK WILL SEE THE LOW PRESSURE SYSTEMS TO THE NORTHEAST AND EAST MERGE NEAR/NORTH OF THE GREAT LAKES. MEANWHILE NORTHWEST FLOW DOMINATES THE HIGH PLAINS AND AN UPPER LEVEL TROUGH DIGS ACROSS THE PACIFIC COAST. THE LOW PRESSURE SYSTEM TO THE NORTHEAST WILL DRAW SOME COOL AND DRY CANADIAN AIR TO THE REGION. TEMPERATURES WILL BE THE MAIN FOCUS THROUGH MID WEEK AND ARE TRICKY. THE DRY AIR MOVING SOUTH WILL ALLOW FOR DEW POINTS TO FALL INTO THE TEENS AND 20S...HOWEVER WITH THE RECENT HEAVY RAIN...THOUGHT MODELS ARE A TAD TO DRY SO DID RAISE SLIGHTLY BUT COULD SEE THEM BEING HIGHER...ESPECIALLY BY WED. SKIES WILL GENERALLY BE MOSTLY CLEAR...ALTHOUGH A COUPLE WEAK CLIPPERS MAY BRING A BRIEF INCREASE OF CLOUDS. WITH MOSTLY CLEAR SKIES AND DRY AIR TEMPS TO LIKELY FALL TO OR BELOW THE FREEZING MARK FOR THE FIRST FEW DAYS OF THE WEEK...UNLESS BL MOISTURE ENDS UP BEING MORE THAN EXPECTED FROM RECENT RAIN. MEANWHILE AFTERNOON SUN WILL HELP OFFSET THE COOL CONDITIONS AND BE ABLE TO AID IN MIXING THE BL...SEASONAL HIGHS /50S AND 60S/ EXPECTED. ONE CONCERN WITH HIGHS IS THE COOL TEMPS ALOFT...WHICH MAY RESULT IN SOME AFTERNOON CLOUDS DUE TO STEEP LAPSE RATES DEVELOPING. FAIRLY DRY AIR AT THE SFC SO NOTHING EXPECTED TO REACH THE GROUND. BY THE END OF THE WEEK THE WEST COAST TROUGH WILL BECOME AN OPEN WAVE CROSSING THE DESERT SW/4 CORNERS. A TRANSITION FROM NW TO SW FLOW WILL BRING A RETURN FOR WET WEATHER. MODELS NOT IN THE BEST OF AGREEMENT ON TIMING...BUT DO PUSH THE WAVE ONTO THE SOUTHERN/CENTRAL PLAINS BY THE WEEKEND. SHOULD SEE A BRIEF WINDOW OF RETURN MOIST SOUTHEASTERLY FLOW AHEAD OF THE WAVE. THIS TRACK AND THE INCREASE OF MOISTURE WILL FAVOR A CHANCE FOR RAIN...ALBEIT BETTER FOR SOUTHERN ZONES THAN NORTHERN ZONES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1152 PM CDT SAT APR 18 2015 THE THUNDERSTORMS IN CENTRAL NEBRASKA ARE WEAKENING. LATER TONIGHT...AS THE UPPER LOW MAKES ITS WAY ONTO THE PLAINS... SCATTERED SHOWERS WILL COALESCE INTO WIDESPREAD RAIN AFTER 06Z SOUTH OF AN ONL-MHN-OGA LINE. THEN...AS A FRONT COME THROUGH...RAIN WILL END FROM THE NORTH IN CENTRAL NEBRASKA BY 11Z AND IN SOUTH CENTRAL AND SOUTHWEST NEBRASKA EARLY AFTERNOON. THE RAIN IS EXPECTED TO END BBW-LBF-IML AROUND 13Z. AFTER 08Z...WIND WILL SHIFT TO 340-360 AT 10-16KT AND THEN INCREASE TO 14-18G24-30KT BY 14Z && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1154 PM CDT SAT APR 18 2015 .SYNOPSIS... ISSUED AT 255 PM CDT SAT APR 18 2015 ANALYSIS OF THE 19Z MSL DATA SHOWED LOW PRESSURE CENTERED IN WESTERN KANSAS WITH A WARM FRONT ACROSS NORTHERN KANSAS...A COLD FRONT INTO THE OKLAHOMA/TEXAS PANHANDLE AND AN INVERTED TROUGH FROM SOUTHWEST TO NORTH CENTRAL NEBRASKA. IN THE UPPER LEVELS...THE WATER VAPOR IMAGERY SHOWED A CLOSED CYCLONIC CIRCULATION LOCATED IN EASTERN COLORADO. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 255 PM CDT SAT APR 18 2015 THE CENTER OF STRONG CUT OFF LOW /H500 MB TEMP -25C/ IS NEAR AKRON COLORADO THIS AFTERNOON. HIGH RES MODELS INSIST THAT CONVECTION...AIDED BY A SIGNIFICANT PV ANOMALY ROTATING NORTHEAST INTO WESTERN KANSAS AROUND THE LOW CENTER...WILL DEVELOP ONCE AGAIN ACROSS NORTHWEST KANSAS AND SOUTHWEST NEBRASKA LATE THIS AFTERNOON AND THIS EVENING. THE ACTIVITY WILL GROW UPSCALE MUCH LIKE LAST NIGHT AS IT MOVES NORTH/NORTHEAST INTO THE REST OF WESTERN...CENTRAL AND NORTH CENTRAL NEBRASKA TONIGHT. AS FAR AS SEVERE POTENTIAL...GOOD SURFACE HEATING UNDERWAY ATTM ACROSS SOUTHWEST NEBRASKA AND NORTHWEST KANSAS. EXPECTING MUCAPE ON THE ORDER OF 1500 J/KG BY LATE AFTERNOON INTO THE EVENING HOURS. ONE WEAKNESS ARE THE WIND FIELDS ARE FAIRLY LIGHT...AND NOT A A LOT OF VEERING WITH HEIGHT. NEVERTHELESS WITH THE STEEP LOW AND MID LEVEL LAPSE RATES...WILL SEE SOME VIGOROUS UPDRAFTS...AND SOME HAIL LIKELY WITH THOSE STRONGER UPDRAFTS. TORNADO POTENTIAL IS NOT ZERO...BUT AGAIN WITH THE WEAK WIND FIELDS AND LIMITED VEERING...NOT EXPECTING THAT TO BE THE PRIMARY RISK. IF A TORNADO OCCURS IT WOULD MORE THAN LIKELY BE WEAK. K INDICES ARE HIGH...AND LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. THE CLOSED H500 MB CIRCULATION IS FORECASTED TO MIGRATE INTO NORTHWEST KANSAS BY SUNDAY MORNING...AND CONTINUE EAST ACROSS KANSAS DURING THE DAY. A SMALL DEFORMATION BAND OF PRECIPITATION IS LIKELY ON THE NORTH AND WEST SIDE OF THE TRACK. THE EXACT TRACK OF THE LOW CENTER IS UNCERTAIN...AS CONVECTION LIKELY TO INFLUENCE THE MASS FIELD AND EXPECT THE FINAL TRACK COULD END UP A LITTLE FARTHER NORTH. THIS IS HINTED IN THE LATEST RUN OF THE RAP MODEL. OTHERWISE A COLD FRONT ASSOCIATED WITH A SEPARATE NORTHERN STREAM SYSTEM WILL CRASH THROUGH THE AREA...BRINGING GUSTY NORTHWEST WINDS TO THE REGION. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 255 PM CDT SAT APR 18 2015 MEDIUM RANGE...(SUNDAY NIGHT THROUGH TUESDAY) THE UPPER LEVEL LOW ACROSS COLORADO WILL LIFT OUT AND COLLIDE WITH AN UPPER LEVEL SHORT WAVE ACROSS ACROSS THE NORTHERN GREAT LAKES FORMING A VERY LARGE CLOSED UPPER LOW. UPSTREAM HEIGHTS RISE SHARPLY ACROSS NRN CANADA SUPPORTING A BROAD AREA OF HIGH PRESSURE WHICH CIRCULATE COOL AIR SOUTH THROUGH THE PLAINS AND MIDWEST. THIS KEEPS THE FORECAST AREA IN COOL NORTHWEST FLOW. DAYTIME MIXING PRODUCES PARTLY CLOUDY SKIES MONDAY AND TUESDAY PLACING A LIMIT ON HEATING. MONDAY WOULD BE A WINDY DAY WITH NORTHWEST WINDS INCREASING TO 20 TO 30 MPH IN THE AFTN WHICH WEAKEN AT SUNSET. WINDS STAY REASONABLY STRONG SUNDAY NIGHT ALSO. THE EFFECT ON TEMPERATURES WOULD BE FOR LOWS MONDAY MORNING FALLING INTO THE UPPER 20S ACROSS WESTERN NEBRASKA BUT ABOVE FREEZING EAST OF HIGHWAY 83. LOWS FALL BELOW FREEZING EVERYWHERE MONDAY NIGHT EXCEPT ALONG HIGHWAY 281. HIGHS RISE INTO THE 50S MONDAY AND LOWER 60S TUESDAY. THE FORECAST IS DRY AND THE MODELS INDICATE DEW POINTS FALL INTO TEENS AND 20S SUNDAY NIGHT THROUGH TUESDAY. THE RISK TO THE FORECAST IS THAT THE VERY DRY AIR COULD SUPPORT COLDER LOWS THAN FORECAST BUT THAT WOULD COMPETE DIRECTLY WITH THE WARM WET GROUND FROM THE HEAVY RAINFALL. EXTENDED RANGE...(TUESDAY NIGHT THROUGH SATURDAY) A RIDGE IN WESTERN NORTH AMERICA CONTINUES TO BUILD INTO THE NORTHWEST TERRITORIES AND NORTHERN ALBERTA OPENING UP A PATH FROM NUNAVUT IN EXTREME NORTHERN CANADA TO NORTH CENTRAL AND NORTHEAST NEBRASKA. AS A RESULT...TEMPERATURES ARE EXPECTED TO BE A LITTLE BELOW THE SEASONAL AVERAGES IN THE NORTHEAST NEBRASKA SANDHILLS AND THE NIOBRARA VALLEY WITH NIGHTTIME TEMPERATURES AT OR BELOW FREEZING INTO FRIDAY MORNING. EVEN IN THE WESTERN SANDHILLS...THE EASTERN PANHANDLE AND SOUTHWEST NEBRASKA WILL BE SLIGHTLY BELOW AVERAGE WITH LOWS IN THE LOW TO MID 30S. IN THE SOUTHWEST STATES...A TROUGH DIGS INTO SOUTHERN CALIFORNIA RESULTING IN SOUTHWEST FLOW ALOFT ACROSS THE CENTRAL PLAINS. A WEAK INVERTED TROUGH MOVING ACROSS THE PLAINS COULD BRING THE POSSIBILITY OF SHOWERS TO CENTRAL AND WESTERN NEBRASKA THURSDAY THROUGH SATURDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1152 PM CDT SAT APR 18 2015 THE THUNDERSTORMS IN CENTRAL NEBRASKA ARE WEAKENING. LATER TONIGHT...AS THE UPPER LOW MAKES ITS WAY ONTO THE PLAINS... SCATTERED SHOWERS WILL COALESCE INTO WIDESPREAD RAIN AFTER 06Z SOUTH OF AN ONL-MHN-OGA LINE. THEN...AS A FRONT COME THROUGH...RAIN WILL END FROM THE NORTH IN CENTRAL NEBRASKA BY 11Z AND IN SOUTH CENTRAL AND SOUTHWEST NEBRASKA EARLY AFTERNOON. THE RAIN IS EXPECTED TO END BBW-LBF-IML AROUND 13Z. AFTER 08Z...WIND WILL SHIFT TO 340-360 AT 10-16KT AND THEN INCREASE TO 14-18G24-30KT BY 14Z && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SPRINGER SHORT TERM...TAYLOR LONG TERM...CDC/SPRINGER AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1149 AM MDT SUN APR 19 2015 .AVIATION... 18Z TAF CYCLE STRONG BACKDOOR COLD FRONT HAS MOVED SOUTH ACROSS OF THE EASTERN PLAINS. N WIND GUSTS OF 30 TO 35 KT WILL CONTINUE FOR A COUPLE MORE HOURS AT RTN AND TCC BEFORE DIMINISHING. GUSTS AROUND 40 KT AT CAO AND CVN. THE BACKDOOR FRONT WILL HELP TRIGGER ISOLATED AFTERNOON AND EARLY EVE -SHRA AND -TSRA TODAY...MAINLY OVER THE SANGRE DE CRISTO MOUNTAINS AND ACROSS THE NE. MORE ISOLATED ACTIVITY POSSIBLE ALONG THE CENTRAL MOUNTAIN CHAIN AND THEIR E SLOPES. WILL CARRY VCTS AND VCSH AT LVS WITH NO MENTION AT THE OTHER TAF SITES. ISOLATED...HIGHER BASED CONVECTION POSSIBLE ACROSS THE SW MTS THIS AFTN. LATE TONIGHT THERE IS A POSSIBILITY OF SOME NEAR MVFR CIGS ACROSS THE E...INCLUDING LVS..TCC AND ROW. && .PREV DISCUSSION...913 AM MDT SUN APR 19 2015... .UPDATE... ADDED QUAY AND CURRY COUNTIES TO THE WIND ADVY FOR TODAY AND TWEAKED UP WIND SPEEDS OUT THERE. OTHERWISE NO CHANGES. && .PREV DISCUSSION...337 AM MDT SUN APR 19 2015... .SYNOPSIS... AN OVERALL UNSETTLED WEATHER PATTERN WILL CONTINUE FOR THE NORTHERN HIGH TERRAIN AND THE NORTHEAST PLAINS THROUGH ALL OF THIS WEEK. HIGH TEMPERATURES WILL SLOWLY TREND BACK TOWARD NORMAL THROUGH THE MIDDLE OF THE WEEK AHEAD OF THE NEXT STORM SYSTEM APPROACHING FROM THE WEST. DRY SOUTHWEST WINDS WILL INCREASE WEDNESDAY AND THURSDAY FOR WESTERN AND CENTRAL NEW MEXICO. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE AGAIN FOR ALL AREAS FRIDAY AS THE CORE OF AN UPPER LOW SLIDES OVERHEAD. COOLER TEMPERATURES WILL MOVE BACK INTO THE AREA BEHIND THIS SYSTEM...WHILE THE CHANCES OF PRECIPITATION CONTINUE OVER THE NORTH THROUGH NEXT WEEKEND. && .DISCUSSION... THE FINAL VESTIGES OF WRAP-AROUND PRECIP ARE IMPACTING THE FRONT RANGE OF COLORADO THIS MORNING AS EVIDENCED BY WIDESPREAD SHOWERS AND GUSTY NORTH WINDS. THIS ACTIVITY IS INDICATED BY THE 00Z/06Z NAM AND HRRR GUIDANCE TO CLIP NORTHEAST NM THIS MORNING. QPF WILL BE LIGHT WITH MOST AREAS REPORTING LESS THAN A TENTH. HIGHS AGAIN TODAY WILL BE BELOW NORMAL ALL AREAS...WITH READINGS 10-15F BELOW NORMAL FOR THE EAST. HIGH PRESSURE BUILDING DOWN THE FRONT RANGE TONIGHT BEHIND THE DEPARTING UPPER LOW WILL HELP FORCE LIGHT GAP WINDS INTO THE RIO GRANDE VALLEY LATE TONIGHT. ONE LAST UPPER VORT TRANSLATION WITHIN NW FLOW BEHIND THE DEPARTING WAVE WILL SLIDE OVER THE NORTHERN MTS AND NE PLAINS MONDAY. THIS WILL FORCE ANOTHER ROUND OF AFTERNOON SHOWERS NEAR THE HIGH TERRAIN AS FAR SOUTH AS I-40. AGAIN TEMPS WILL BE BELOW NORMAL WITH A SLIGHT TREND TOWARD NORMAL FOR THE FAR WEST. AN AMORPHOUS COMPLEX OF UPPER LEVEL LOW PRESSURE CURRENTLY TAKING SHAPE ALONG THE WEST COAST WILL BECOME THE NEXT WEATHER PLAYER FOR MID TO LATE WEEK. GUIDANCE SHOWS H5 HEIGHTS DEEPENING INTO A 562DM LOW TUESDAY OVER SOUTHERN CALIFORNIA WITH A WEAK SHORTWAVE RIDGE SLIDING OVER NM. THIS WILL TREND SHOWER AND WIND ACTIVITY DOWNWARD FOR NM. A 90-110KT 300MB JET AXIS THEN CARVES SOUTHWARD ALONG THE WEST COAST AND DEEPENS THE TROUGH INTO A TIGHTLY WOUND 550DM H5 LOW OVER SOUTHERN CALIFORNIA THROUGH THURSDAY. THIS WILL INCREASE MID LEVEL FLOW AND DEEPEN THE LEE SIDE TROUGH OVER EASTERN NM. WINDS AND TEMPS WILL INCREASE OVER THE STATE WITH SOME POSSIBLE MARGINAL FIRE WEATHER ISSUES NOTED WEDNESDAY AND/OR THURSDAY. BEYOND THURSDAY THERE IS CONSIDERABLE UNCERTAINTY REGARDING THE TRANSLATION OF LOW PRESSURE OVER NM BY FRIDAY/SATURDAY AND INTO NEXT WEEK. THE GFS AND ECMWF OPEN THE WAVE AND SLIDE DISORGANIZED PRECIP OVER THE AREA...FOLLOWED BY A SERIES OF FAST MOVING WEAKLY DEFINED SHORTWAVE TROUGHS AND RIDGES. GUYER && .FIRE WEATHER... WHILE SOME POTENTIAL STILL REMAINS...AS IT CURRENTLY LOOKS THE RISK OF A RETURN OF CRITICAL FIRE WX CONDITIONS THURSDAY AND FRIDAY HAS DIMINISHED SOMEWHAT. A BACK DOOR FRONT MOVING ACROSS THE EASTERN PLAINS THIS MORN AND INTO THE AFTN WILL BRING INCREASINGLY STRONG AND GUSTY WINDS TO THE NE PLAINS AND TO A LESSER DEGREE THE EAST CENTRAL PLAINS THIS MORN. GUSTS NEAR 45 OR 50 MPH ARE POSSIBLE NEAR CLAYTON THIS MORN. WIND SPEEDS ARE EXPECTED TO DECREASE SOMEWHAT THIS AFTN. CRITICAL FIRE WX CONDITIONS NOT EXPECTED AS HUMIDITIES TO REMAIN TOO HIGH. AFTN TEMPS WILL ONLY BE SLIGHTLY COOLER TODAY AS COMPARED TO SATURDAY BEHIND THE FRONT. AS THE FRONT BACKS UP TO THE CENTRAL MTN CHAIN...EXPECT A FEW HIGH BASED SHOWERS AND THUNDERSTORMS TO DEVELOP DUE TO UPSLOPE FLOW...MORE SO ALONG THE EAST SLOPES OF THE SANGRE DE CRISTO MTNS AND LESS SO FARTHER SOUTH. HUMIDITY RECOVERIES TONIGHT WILL BE GOOD TO EXCELLENT MOST AREAS OUTSIDE OF WEST CENTRAL AND SW NM WHERE FAIR TO GOOD RECOVERIES TO BE THE RULE. LOW TEMPS WILL BE A LITTLE ABOVE NORMAL WEST AND CENTRAL...A BIT BELOW EAST. HIGH TEMPS ON SUNDAY WILL REMAIN BELOW NORMAL ACROSS THE EAST DUE TO THE FRONTAL PASSAGE...THOUGH WILL BE INCHING UP TOWARD NORMAL ACROSS THE WEST. LATER MON...WEAK RIDGE ALOFT WILL DEVELOP ACROSS WESTERN NM...THOUGH ENOUGH RESIDUAL MOISTURE WILL BE AROUND TO TRIGGER A FEW HIGH BASED BUILDUPS AND VIRGA IN THE AFTERNOON HOURS. A FEW SPRINKLES MAY ACTUALLY REACH THE GROUND ACROSS THE NORTHERN HIGH TERRAIN...THOUGH THE BIGGER CONCERN MAY BE ERRATIC WIND GUSTS WITH ANY VIRGA ACROSS WESTERN NM. OTHERWISE TEMPS SHOULD WARM TO AROUND 5 DEGREES OF NORMAL EAST...VERY CLOSE TO NORMAL WEST. THE BACK DOOR COLD FRONT EARLIER SCHEDULED TO ARRIVE LATER MON NIGHT INTO TUE MORN HAS BEEN MARGINALIZED AND IN SOME MODELS ELIMINATED FROM THE SCENE COMPLETELY. STILL MAY BE JUST ENOUGH MOISTURE AND WEAK UPSLOPE TO CREATE A FEW SHOWERS AND THUNDERSTORMS TUE AFTN WITH AID OF AFTN HEATING. WED LOOKS TO BE BREEZY IN MANY AREAS...BUT FOR THE MOST PART THE STRONGEST WINDS STILL ARE EXPECTED TO ARRIVE THU AND FRI. BUT CRITICAL CONDITIONS HAVE SHRUNK SIGNIFICANTLY THU AND DO NOT APPEAR AT ALL FOR FRI. THIS MAY ONLY BE A TEMPORARY REDUCTION AS FCST MODELS SEEM TO BE IN TRANSITION AGAIN IN THEIR DEPICTION OF UPPER LVL LOW PRESSURE EVOLUTION OFF TO OUR WEST. THE BACK DOOR FRONT WILL BE REINFORCED ACROSS NE NM AND SOME THUNDERSTORMS MAY DEVELOP THERE THU AFTN. NO VENTILATION ISSUES ARE EXPECTED FOR THE NEXT 6 DAYS...WITH MAINLY VERY GOOD TO EXCELLENT VENT RATES EXPECTED...THOUGH FAR NORTHEAST NM MAY DROP INTO THE FAIR OR GOOD CATEGORIES MID TO LATE WEEK. SAT MAY SEE SOME EROSION OF VENTILATION RATES. 43 && .ABQ WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 4 PM MDT THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ530-534-535. && $$ 40
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
913 AM MDT SUN APR 19 2015 .UPDATE... ADDED QUAY AND CURRY COUNTIES TO THE WIND ADVY FOR TODAY AND TWEAKED UP WIND SPEEDS OUT THERE. OTHERWISE NO CHANGES. && .PREV DISCUSSION...553 AM MDT SUN APR 19 2015... .AVIATION... 12Z TAF CYCLE SIGNIFICANT BACKDOOR COLD FRONT WILL SLIDE FARTHER SOUTH ACROSS THE ERN PLAINS THIS MORN. NORTH WINDS OF 18 TO 30KT WITH GUSTS BETWEEN 35 AND 45KT CAN BE EXPECTED ACROSS THE NE QUARTER OF NM... THE STRONGEST IN THE VICINITY OF UNION COUNTY BETWEEN 14Z AND 19Z SUNDAY. THE BACKDOOR FRONT WILL HELP TRIGGER ISOLATED AFTERNOON AND EARLY EVE -SHRA AND -TSRA TODAY...MAINLY OVER THE NORTHERN MTS AND ALONG THE EAST SLOPES OF THE CENTRAL MOUNTAIN CHAIN INCLUDING KLVS...EAST SLOPES OF THE SANGRE DE CRISTOS MOST FAVORED. ISOLATED EVEN HIGHER BASED CONVECTION POSSIBLE ALSO ACROSS THE SW MTS THIS AFTN. LATE TONIGHT THERE IS A POSSIBILITY OF SOME NEAR MVFR CIGS ACROSS AREAS E AND SE FROM THE E SLOPES OF THE SANGRE DE CRISTOS. 43 && .PREV DISCUSSION...337 AM MDT SUN APR 19 2015... .SYNOPSIS... AN OVERALL UNSETTLED WEATHER PATTERN WILL CONTINUE FOR THE NORTHERN HIGH TERRAIN AND THE NORTHEAST PLAINS THROUGH ALL OF THIS WEEK. HIGH TEMPERATURES WILL SLOWLY TREND BACK TOWARD NORMAL THROUGH THE MIDDLE OF THE WEEK AHEAD OF THE NEXT STORM SYSTEM APPROACHING FROM THE WEST. DRY SOUTHWEST WINDS WILL INCREASE WEDNESDAY AND THURSDAY FOR WESTERN AND CENTRAL NEW MEXICO. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE AGAIN FOR ALL AREAS FRIDAY AS THE CORE OF AN UPPER LOW SLIDES OVERHEAD. COOLER TEMPERATURES WILL MOVE BACK INTO THE AREA BEHIND THIS SYSTEM...WHILE THE CHANCES OF PRECIPITATION CONTINUE OVER THE NORTH THROUGH NEXT WEEKEND. && .DISCUSSION... THE FINAL VESTIGES OF WRAP-AROUND PRECIP ARE IMPACTING THE FRONT RANGE OF COLORADO THIS MORNING AS EVIDENCED BY WIDESPREAD SHOWERS AND GUSTY NORTH WINDS. THIS ACTIVITY IS INDICATED BY THE 00Z/06Z NAM AND HRRR GUIDANCE TO CLIP NORTHEAST NM THIS MORNING. QPF WILL BE LIGHT WITH MOST AREAS REPORTING LESS THAN A TENTH. HIGHS AGAIN TODAY WILL BE BELOW NORMAL ALL AREAS...WITH READINGS 10-15F BELOW NORMAL FOR THE EAST. HIGH PRESSURE BUILDING DOWN THE FRONT RANGE TONIGHT BEHIND THE DEPARTING UPPER LOW WILL HELP FORCE LIGHT GAP WINDS INTO THE RIO GRANDE VALLEY LATE TONIGHT. ONE LAST UPPER VORT TRANSLATION WITHIN NW FLOW BEHIND THE DEPARTING WAVE WILL SLIDE OVER THE NORTHERN MTS AND NE PLAINS MONDAY. THIS WILL FORCE ANOTHER ROUND OF AFTERNOON SHOWERS NEAR THE HIGH TERRAIN AS FAR SOUTH AS I-40. AGAIN TEMPS WILL BE BELOW NORMAL WITH A SLIGHT TREND TOWARD NORMAL FOR THE FAR WEST. AN AMORPHOUS COMPLEX OF UPPER LEVEL LOW PRESSURE CURRENTLY TAKING SHAPE ALONG THE WEST COAST WILL BECOME THE NEXT WEATHER PLAYER FOR MID TO LATE WEEK. GUIDANCE SHOWS H5 HEIGHTS DEEPENING INTO A 562DM LOW TUESDAY OVER SOUTHERN CALIFORNIA WITH A WEAK SHORTWAVE RIDGE SLIDING OVER NM. THIS WILL TREND SHOWER AND WIND ACTIVITY DOWNWARD FOR NM. A 90-110KT 300MB JET AXIS THEN CARVES SOUTHWARD ALONG THE WEST COAST AND DEEPENS THE TROUGH INTO A TIGHTLY WOUND 550DM H5 LOW OVER SOUTHERN CALIFORNIA THROUGH THURSDAY. THIS WILL INCREASE MID LEVEL FLOW AND DEEPEN THE LEE SIDE TROUGH OVER EASTERN NM. WINDS AND TEMPS WILL INCREASE OVER THE STATE WITH SOME POSSIBLE MARGINAL FIRE WEATHER ISSUES NOTED WEDNESDAY AND/OR THURSDAY. BEYOND THURSDAY THERE IS CONSIDERABLE UNCERTAINTY REGARDING THE TRANSLATION OF LOW PRESSURE OVER NM BY FRIDAY/SATURDAY AND INTO NEXT WEEK. THE GFS AND ECMWF OPEN THE WAVE AND SLIDE DISORGANIZED PRECIP OVER THE AREA...FOLLOWED BY A SERIES OF FAST MOVING WEAKLY DEFINED SHORTWAVE TROUGHS AND RIDGES. GUYER && .FIRE WEATHER... WHILE SOME POTENTIAL STILL REMAINS...AS IT CURRENTLY LOOKS THE RISK OF A RETURN OF CRITICAL FIRE WX CONDITIONS THURSDAY AND FRIDAY HAS DIMINISHED SOMEWHAT. A BACK DOOR FRONT MOVING ACROSS THE EASTERN PLAINS THIS MORN AND INTO THE AFTN WILL BRING INCREASINGLY STRONG AND GUSTY WINDS TO THE NE PLAINS AND TO A LESSER DEGREE THE EAST CENTRAL PLAINS THIS MORN. GUSTS NEAR 45 OR 50 MPH ARE POSSIBLE NEAR CLAYTON THIS MORN. WIND SPEEDS ARE EXPECTED TO DECREASE SOMEWHAT THIS AFTN. CRITICAL FIRE WX CONDITIONS NOT EXPECTED AS HUMIDITIES TO REMAIN TOO HIGH. AFTN TEMPS WILL ONLY BE SLIGHTLY COOLER TODAY AS COMPARED TO SATURDAY BEHIND THE FRONT. AS THE FRONT BACKS UP TO THE CENTRAL MTN CHAIN...EXPECT A FEW HIGH BASED SHOWERS AND THUNDERSTORMS TO DEVELOP DUE TO UPSLOPE FLOW...MORE SO ALONG THE EAST SLOPES OF THE SANGRE DE CRISTO MTNS AND LESS SO FARTHER SOUTH. HUMIDITY RECOVERIES TONIGHT WILL BE GOOD TO EXCELLENT MOST AREAS OUTSIDE OF WEST CENTRAL AND SW NM WHERE FAIR TO GOOD RECOVERIES TO BE THE RULE. LOW TEMPS WILL BE A LITTLE ABOVE NORMAL WEST AND CENTRAL...A BIT BELOW EAST. HIGH TEMPS ON SUNDAY WILL REMAIN BELOW NORMAL ACROSS THE EAST DUE TO THE FRONTAL PASSAGE...THOUGH WILL BE INCHING UP TOWARD NORMAL ACROSS THE WEST. LATER MON...WEAK RIDGE ALOFT WILL DEVELOP ACROSS WESTERN NM...THOUGH ENOUGH RESIDUAL MOISTURE WILL BE AROUND TO TRIGGER A FEW HIGH BASED BUILDUPS AND VIRGA IN THE AFTERNOON HOURS. A FEW SPRINKLES MAY ACTUALLY REACH THE GROUND ACROSS THE NORTHERN HIGH TERRAIN...THOUGH THE BIGGER CONCERN MAY BE ERRATIC WIND GUSTS WITH ANY VIRGA ACROSS WESTERN NM. OTHERWISE TEMPS SHOULD WARM TO AROUND 5 DEGREES OF NORMAL EAST...VERY CLOSE TO NORMAL WEST. THE BACK DOOR COLD FRONT EARLIER SCHEDULED TO ARRIVE LATER MON NIGHT INTO TUE MORN HAS BEEN MARGINALIZED AND IN SOME MODELS ELIMINATED FROM THE SCENE COMPLETELY. STILL MAY BE JUST ENOUGH MOISTURE AND WEAK UPSLOPE TO CREATE A FEW SHOWERS AND THUNDERSTORMS TUE AFTN WITH AID OF AFTN HEATING. WED LOOKS TO BE BREEZY IN MANY AREAS...BUT FOR THE MOST PART THE STRONGEST WINDS STILL ARE EXPECTED TO ARRIVE THU AND FRI. BUT CRITICAL CONDITIONS HAVE SHRUNK SIGNIFICANTLY THU AND DO NOT APPEAR AT ALL FOR FRI. THIS MAY ONLY BE A TEMPORARY REDUCTION AS FCST MODELS SEEM TO BE IN TRANSITION AGAIN IN THEIR DEPICTION OF UPPER LVL LOW PRESSURE EVOLUTION OFF TO OUR WEST. THE BACK DOOR FRONT WILL BE REINFORCED ACROSS NE NM AND SOME THUNDERSTORMS MAY DEVELOP THERE THU AFTN. NO VENTILATION ISSUES ARE EXPECTED FOR THE NEXT 6 DAYS...WITH MAINLY VERY GOOD TO EXCELLENT VENT RATES EXPECTED...THOUGH FAR NORTHEAST NM MAY DROP INTO THE FAIR OR GOOD CATEGORIES MID TO LATE WEEK. SAT MAY SEE SOME EROSION OF VENTILATION RATES. 43 && .ABQ WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 4 PM MDT THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ530-534-535. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
553 AM MDT SUN APR 19 2015 .AVIATION... 12Z TAF CYCLE SIGNIFICANT BACKDOOR COLD FRONT WILL SLIDE FARTHER SOUTH ACROSS THE ERN PLAINS THIS MORN. NORTH WINDS OF 18 TO 30KT WITH GUSTS BETWEEN 35 AND 45KT CAN BE EXPECTED ACROSS THE NE QUARTER OF NM... THE STRONGEST IN THE VICINITY OF UNION COUNTY BETWEEN 14Z AND 19Z SUNDAY. THE BACKDOOR FRONT WILL HELP TRIGGER ISOLATED AFTERNOON AND EARLY EVE -SHRA AND -TSRA TODAY...MAINLY OVER THE NORTHERN MTS AND ALONG THE EAST SLOPES OF THE CENTRAL MOUNTAIN CHAIN INCLUDING KLVS...EAST SLOPES OF THE SANGRE DE CRISTOS MOST FAVORED. ISOLATED EVEN HIGHER BASED CONVECTION POSSIBLE ALSO ACROSS THE SW MTS THIS AFTN. LATE TONIGHT THERE IS A POSSIBILITY OF SOME NEAR MVFR CIGS ACROSS AREAS E AND SE FROM THE E SLOPES OF THE SANGRE DE CRISTOS. 43 && .PREV DISCUSSION...337 AM MDT SUN APR 19 2015... .SYNOPSIS... AN OVERALL UNSETTLED WEATHER PATTERN WILL CONTINUE FOR THE NORTHERN HIGH TERRAIN AND THE NORTHEAST PLAINS THROUGH ALL OF THIS WEEK. HIGH TEMPERATURES WILL SLOWLY TREND BACK TOWARD NORMAL THROUGH THE MIDDLE OF THE WEEK AHEAD OF THE NEXT STORM SYSTEM APPROACHING FROM THE WEST. DRY SOUTHWEST WINDS WILL INCREASE WEDNESDAY AND THURSDAY FOR WESTERN AND CENTRAL NEW MEXICO. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE AGAIN FOR ALL AREAS FRIDAY AS THE CORE OF AN UPPER LOW SLIDES OVERHEAD. COOLER TEMPERATURES WILL MOVE BACK INTO THE AREA BEHIND THIS SYSTEM...WHILE THE CHANCES OF PRECIPITATION CONTINUE OVER THE NORTH THROUGH NEXT WEEKEND. && .DISCUSSION... THE FINAL VESTIGES OF WRAP-AROUND PRECIP ARE IMPACTING THE FRONT RANGE OF COLORADO THIS MORNING AS EVIDENCED BY WIDESPREAD SHOWERS AND GUSTY NORTH WINDS. THIS ACTIVITY IS INDICATED BY THE 00Z/06Z NAM AND HRRR GUIDANCE TO CLIP NORTHEAST NM THIS MORNING. QPF WILL BE LIGHT WITH MOST AREAS REPORTING LESS THAN A TENTH. HIGHS AGAIN TODAY WILL BE BELOW NORMAL ALL AREAS...WITH READINGS 10-15F BELOW NORMAL FOR THE EAST. HIGH PRESSURE BUILDING DOWN THE FRONT RANGE TONIGHT BEHIND THE DEPARTING UPPER LOW WILL HELP FORCE LIGHT GAP WINDS INTO THE RIO GRANDE VALLEY LATE TONIGHT. ONE LAST UPPER VORT TRANSLATION WITHIN NW FLOW BEHIND THE DEPARTING WAVE WILL SLIDE OVER THE NORTHERN MTS AND NE PLAINS MONDAY. THIS WILL FORCE ANOTHER ROUND OF AFTERNOON SHOWERS NEAR THE HIGH TERRAIN AS FAR SOUTH AS I-40. AGAIN TEMPS WILL BE BELOW NORMAL WITH A SLIGHT TREND TOWARD NORMAL FOR THE FAR WEST. AN AMORPHOUS COMPLEX OF UPPER LEVEL LOW PRESSURE CURRENTLY TAKING SHAPE ALONG THE WEST COAST WILL BECOME THE NEXT WEATHER PLAYER FOR MID TO LATE WEEK. GUIDANCE SHOWS H5 HEIGHTS DEEPENING INTO A 562DM LOW TUESDAY OVER SOUTHERN CALIFORNIA WITH A WEAK SHORTWAVE RIDGE SLIDING OVER NM. THIS WILL TREND SHOWER AND WIND ACTIVITY DOWNWARD FOR NM. A 90-110KT 300MB JET AXIS THEN CARVES SOUTHWARD ALONG THE WEST COAST AND DEEPENS THE TROUGH INTO A TIGHTLY WOUND 550DM H5 LOW OVER SOUTHERN CALIFORNIA THROUGH THURSDAY. THIS WILL INCREASE MID LEVEL FLOW AND DEEPEN THE LEE SIDE TROUGH OVER EASTERN NM. WINDS AND TEMPS WILL INCREASE OVER THE STATE WITH SOME POSSIBLE MARGINAL FIRE WEATHER ISSUES NOTED WEDNESDAY AND/OR THURSDAY. BEYOND THURSDAY THERE IS CONSIDERABLE UNCERTAINTY REGARDING THE TRANSLATION OF LOW PRESSURE OVER NM BY FRIDAY/SATURDAY AND INTO NEXT WEEK. THE GFS AND ECMWF OPEN THE WAVE AND SLIDE DISORGANIZED PRECIP OVER THE AREA...FOLLOWED BY A SERIES OF FAST MOVING WEAKLY DEFINED SHORTWAVE TROUGHS AND RIDGES. GUYER && .FIRE WEATHER... WHILE SOME POTENTIAL STILL REMAINS...AS IT CURRENTLY LOOKS THE RISK OF A RETURN OF CRITICAL FIRE WX CONDITIONS THURSDAY AND FRIDAY HAS DIMINISHED SOMEWHAT. A BACK DOOR FRONT MOVING ACROSS THE EASTERN PLAINS THIS MORN AND INTO THE AFTN WILL BRING INCREASINGLY STRONG AND GUSTY WINDS TO THE NE PLAINS AND TO A LESSER DEGREE THE EAST CENTRAL PLAINS THIS MORN. GUSTS NEAR 45 OR 50 MPH ARE POSSIBLE NEAR CLAYTON THIS MORN. WIND SPEEDS ARE EXPECTED TO DECREASE SOMEWHAT THIS AFTN. CRITICAL FIRE WX CONDITIONS NOT EXPECTED AS HUMIDITIES TO REMAIN TOO HIGH. AFTN TEMPS WILL ONLY BE SLIGHTLY COOLER TODAY AS COMPARED TO SATURDAY BEHIND THE FRONT. AS THE FRONT BACKS UP TO THE CENTRAL MTN CHAIN...EXPECT A FEW HIGH BASED SHOWERS AND THUNDERSTORMS TO DEVELOP DUE TO UPSLOPE FLOW...MORE SO ALONG THE EAST SLOPES OF THE SANGRE DE CRISTO MTNS AND LESS SO FARTHER SOUTH. HUMIDITY RECOVERIES TONIGHT WILL BE GOOD TO EXCELLENT MOST AREAS OUTSIDE OF WEST CENTRAL AND SW NM WHERE FAIR TO GOOD RECOVERIES TO BE THE RULE. LOW TEMPS WILL BE A LITTLE ABOVE NORMAL WEST AND CENTRAL...A BIT BELOW EAST. HIGH TEMPS ON SUNDAY WILL REMAIN BELOW NORMAL ACROSS THE EAST DUE TO THE FRONTAL PASSAGE...THOUGH WILL BE INCHING UP TOWARD NORMAL ACROSS THE WEST. LATER MON...WEAK RIDGE ALOFT WILL DEVELOP ACROSS WESTERN NM...THOUGH ENOUGH RESIDUAL MOISTURE WILL BE AROUND TO TRIGGER A FEW HIGH BASED BUILDUPS AND VIRGA IN THE AFTERNOON HOURS. A FEW SPRINKLES MAY ACTUALLY REACH THE GROUND ACROSS THE NORTHERN HIGH TERRAIN...THOUGH THE BIGGER CONCERN MAY BE ERRATIC WIND GUSTS WITH ANY VIRGA ACROSS WESTERN NM. OTHERWISE TEMPS SHOULD WARM TO AROUND 5 DEGREES OF NORMAL EAST...VERY CLOSE TO NORMAL WEST. THE BACK DOOR COLD FRONT EARLIER SCHEDULED TO ARRIVE LATER MON NIGHT INTO TUE MORN HAS BEEN MARGINALIZED AND IN SOME MODELS ELIMINATED FROM THE SCENE COMPLETELY. STILL MAY BE JUST ENOUGH MOISTURE AND WEAK UPSLOPE TO CREATE A FEW SHOWERS AND THUNDERSTORMS TUE AFTN WITH AID OF AFTN HEATING. WED LOOKS TO BE BREEZY IN MANY AREAS...BUT FOR THE MOST PART THE STRONGEST WINDS STILL ARE EXPECTED TO ARRIVE THU AND FRI. BUT CRITICAL CONDITIONS HAVE SHRUNK SIGNIFICANTLY THU AND DO NOT APPEAR AT ALL FOR FRI. THIS MAY ONLY BE A TEMPORARY REDUCTION AS FCST MODELS SEEM TO BE IN TRANSITION AGAIN IN THEIR DEPICTION OF UPPER LVL LOW PRESSURE EVOLUTION OFF TO OUR WEST. THE BACK DOOR FRONT WILL BE REINFORCED ACROSS NE NM AND SOME THUNDERSTORMS MAY DEVELOP THERE THU AFTN. NO VENTILATION ISSUES ARE EXPECTED FOR THE NEXT 6 DAYS...WITH MAINLY VERY GOOD TO EXCELLENT VENT RATES EXPECTED...THOUGH FAR NORTHEAST NM MAY DROP INTO THE FAIR OR GOOD CATEGORIES MID TO LATE WEEK. SAT MAY SEE SOME EROSION OF VENTILATION RATES. 43 && .ABQ WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 4 PM MDT THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ530. && $$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
337 AM MDT SUN APR 19 2015 .SYNOPSIS... AN OVERALL UNSETTLED WEATHER PATTERN WILL CONTINUE FOR THE NORTHERN HIGH TERRAIN AND THE NORTHEAST PLAINS THROUGH ALL OF THIS WEEK. HIGH TEMPERATURES WILL SLOWLY TREND BACK TOWARD NORMAL THROUGH THE MIDDLE OF THE WEEK AHEAD OF THE NEXT STORM SYSTEM APPROACHING FROM THE WEST. DRY SOUTHWEST WINDS WILL INCREASE WEDNESDAY AND THURSDAY FOR WESTERN AND CENTRAL NEW MEXICO. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE AGAIN FOR ALL AREAS FRIDAY AS THE CORE OF AN UPPER LOW SLIDES OVERHEAD. COOLER TEMPERATURES WILL MOVE BACK INTO THE AREA BEHIND THIS SYSTEM...WHILE THE CHANCES OF PRECIPITATION CONTINUE OVER THE NORTH THROUGH NEXT WEEKEND. && .DISCUSSION... THE FINAL VESTIGES OF WRAP-AROUND PRECIP ARE IMPACTING THE FRONT RANGE OF COLORADO THIS MORNING AS EVIDENCED BY WIDESPREAD SHOWERS AND GUSTY NORTH WINDS. THIS ACTIVITY IS INDICATED BY THE 00Z/06Z NAM AND HRRR GUIDANCE TO CLIP NORTHEAST NM THIS MORNING. QPF WILL BE LIGHT WITH MOST AREAS REPORTING LESS THAN A TENTH. HIGHS AGAIN TODAY WILL BE BELOW NORMAL ALL AREAS...WITH READINGS 10-15F BELOW NORMAL FOR THE EAST. HIGH PRESSURE BUILDING DOWN THE FRONT RANGE TONIGHT BEHIND THE DEPARTING UPPER LOW WILL HELP FORCE LIGHT GAP WINDS INTO THE RIO GRANDE VALLEY LATE TONIGHT. ONE LAST UPPER VORT TRANSLATION WITHIN NW FLOW BEHIND THE DEPARTING WAVE WILL SLIDE OVER THE NORTHERN MTS AND NE PLAINS MONDAY. THIS WILL FORCE ANOTHER ROUND OF AFTERNOON SHOWERS NEAR THE HIGH TERRAIN AS FAR SOUTH AS I-40. AGAIN TEMPS WILL BE BELOW NORMAL WITH A SLIGHT TREND TOWARD NORMAL FOR THE FAR WEST. AN AMORPHOUS COMPLEX OF UPPER LEVEL LOW PRESSURE CURRENTLY TAKING SHAPE ALONG THE WEST COAST WILL BECOME THE NEXT WEATHER PLAYER FOR MID TO LATE WEEK. GUIDANCE SHOWS H5 HEIGHTS DEEPENING INTO A 562DM LOW TUESDAY OVER SOUTHERN CALIFORNIA WITH A WEAK SHORTWAVE RIDGE SLIDING OVER NM. THIS WILL TREND SHOWER AND WIND ACTIVITY DOWNWARD FOR NM. A 90-110KT 300MB JET AXIS THEN CARVES SOUTHWARD ALONG THE WEST COAST AND DEEPENS THE TROUGH INTO A TIGHTLY WOUND 550DM H5 LOW OVER SOUTHERN CALIFORNIA THROUGH THURSDAY. THIS WILL INCREASE MID LEVEL FLOW AND DEEPEN THE LEE SIDE TROUGH OVER EASTERN NM. WINDS AND TEMPS WILL INCREASE OVER THE STATE WITH SOME POSSIBLE MARGINAL FIRE WEATHER ISSUES NOTED WEDNESDAY AND/OR THURSDAY. BEYOND THURSDAY THERE IS CONSIDERABLE UNCERTAINTY REGARDING THE TRANSLATION OF LOW PRESSURE OVER NM BY FRIDAY/SATURDAY AND INTO NEXT WEEK. THE GFS AND ECMWF OPEN THE WAVE AND SLIDE DISORGANIZED PRECIP OVER THE AREA...FOLLOWED BY A SERIES OF FAST MOVING WEAKLY DEFINED SHORTWAVE TROUGHS AND RIDGES. GUYER && .FIRE WEATHER... WHILE SOME POTENTIAL STILL REMAINS...AS IT CURRENTLY LOOKS THE RISK OF A RETURN OF CRITICAL FIRE WX CONDITIONS THURSDAY AND FRIDAY HAS DIMINISHED SOMEWHAT. A BACK DOOR FRONT MOVING ACROSS THE EASTERN PLAINS THIS MORN AND INTO THE AFTN WILL BRING INCREASINGLY STRONG AND GUSTY WINDS TO THE NE PLAINS AND TO A LESSER DEGREE THE EAST CENTRAL PLAINS THIS MORN. GUSTS NEAR 45 OR 50 MPH ARE POSSIBLE NEAR CLAYTON THIS MORN. WIND SPEEDS ARE EXPECTED TO DECREASE SOMEWHAT THIS AFTN. CRITICAL FIRE WX CONDITIONS NOT EXPECTED AS HUMIDITIES TO REMAIN TOO HIGH. AFTN TEMPS WILL ONLY BE SLIGHTLY COOLER TODAY AS COMPARED TO SATURDAY BEHIND THE FRONT. AS THE FRONT BACKS UP TO THE CENTRAL MTN CHAIN...EXPECT A FEW HIGH BASED SHOWERS AND THUNDERSTORMS TO DEVELOP DUE TO UPSLOPE FLOW...MORE SO ALONG THE EAST SLOPES OF THE SANGRE DE CRISTO MTNS AND LESS SO FARTHER SOUTH. HUMIDITY RECOVERIES TONIGHT WILL BE GOOD TO EXCELLENT MOST AREAS OUTSIDE OF WEST CENTRAL AND SW NM WHERE FAIR TO GOOD RECOVERIES TO BE THE RULE. LOW TEMPS WILL BE A LITTLE ABOVE NORMAL WEST AND CENTRAL...A BIT BELOW EAST. HIGH TEMPS ON SUNDAY WILL REMAIN BELOW NORMAL ACROSS THE EAST DUE TO THE FRONTAL PASSAGE...THOUGH WILL BE INCHING UP TOWARD NORMAL ACROSS THE WEST. LATER MON...WEAK RIDGE ALOFT WILL DEVELOP ACROSS WESTERN NM...THOUGH ENOUGH RESIDUAL MOISTURE WILL BE AROUND TO TRIGGER A FEW HIGH BASED BUILDUPS AND VIRGA IN THE AFTERNOON HOURS. A FEW SPRINKLES MAY ACTUALLY REACH THE GROUND ACROSS THE NORTHERN HIGH TERRAIN...THOUGH THE BIGGER CONCERN MAY BE ERRATIC WIND GUSTS WITH ANY VIRGA ACROSS WESTERN NM. OTHERWISE TEMPS SHOULD WARM TO AROUND 5 DEGREES OF NORMAL EAST...VERY CLOSE TO NORMAL WEST. THE BACK DOOR COLD FRONT EARLIER SCHEDULED TO ARRIVE LATER MON NIGHT INTO TUE MORN HAS BEEN MARGINALIZED AND IN SOME MODELS ELIMINATED FROM THE SCENE COMPLETELY. STILL MAY BE JUST ENOUGH MOISTURE AND WEAK UPSLOPE TO CREATE A FEW SHOWERS AND THUNDERSTORMS TUE AFTN WITH AID OF AFTN HEATING. WED LOOKS TO BE BREEZY IN MANY AREAS...BUT FOR THE MOST PART THE STRONGEST WINDS STILL ARE EXPECTED TO ARRIVE THU AND FRI. BUT CRITICAL CONDITIONS HAVE SHRUNK SIGNIFICANTLY THU AND DO NOT APPEAR AT ALL FOR FRI. THIS MAY ONLY BE A TEMPORARY REDUCTION AS FCST MODELS SEEM TO BE IN TRANSITION AGAIN IN THEIR DEPICTION OF UPPER LVL LOW PRESSURE EVOLUTION OFF TO OUR WEST. THE BACK DOOR FRONT WILL BE REINFORCED ACROSS NE NM AND SOME THUNDERSTORMS MAY DEVELOP THERE THU AFTN. NO VENTILATION ISSUES ARE EXPECTED FOR THE NEXT 6 DAYS...WITH MAINLY VERY GOOD TO EXCELLENT VENT RATES EXPECTED...THOUGH FAR NORTHEAST NM MAY DROP INTO THE FAIR OR GOOD CATEGORIES MID TO LATE WEEK. SAT MAY SEE SOME EROSION OF VENTILATION RATES. 43 && .AVIATION... 06Z TAF CYCLE A POTENT BACKDOOR COLD FRONT WILL SLIDE DOWN THE ERN PLAINS OVERNIGHT INTO EARLY SUNDAY MORNING. STRONG NORTH WINDS OF 20 TO 30KT WITH GUSTS NEAR 45 KT WILL BE POSSIBLE ACROSS NE NM...ESPECIALLY BETWEEN 09Z AND 18Z SUNDAY. THE BACKDOOR FRONT WILL RESULT IN ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS SUNDAY...MAINLY OVER THE NORTHERN AND SOUTHWEST MOUNTAINS AND ALONG THE EAST SLOPES OF THE CENTRAL MOUNTAIN CHAIN INCLUDING KLVS. WITH WEST TO NORTHWEST FLOW ALOFT IN PLACE AND ELY UPSLOPE SFC FLOW...A FEW STRONG STORMS ARE POSSIBLE DURING THE LATE AFTERNOON AND EARLY EVENING FROM THE EAST SLOPES SANGRE DE CRISTOS EWD TO THE NE PLAINS. 33 && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 65 34 70 37 / 5 0 5 5 DULCE........................... 62 25 62 28 / 10 10 20 10 CUBA............................ 62 32 64 35 / 10 10 10 10 GALLUP.......................... 65 29 69 32 / 5 5 10 5 EL MORRO........................ 59 33 64 35 / 10 10 10 5 GRANTS.......................... 63 29 67 31 / 10 5 10 5 QUEMADO......................... 61 37 65 37 / 10 5 10 5 GLENWOOD........................ 74 45 76 44 / 5 5 5 5 CHAMA........................... 54 25 55 25 / 20 20 20 10 LOS ALAMOS...................... 57 40 62 41 / 20 10 20 10 PECOS........................... 57 33 60 38 / 10 10 10 10 CERRO/QUESTA.................... 54 24 55 26 / 20 30 30 20 RED RIVER....................... 45 25 46 29 / 30 50 40 30 ANGEL FIRE...................... 48 21 51 24 / 30 30 30 20 TAOS............................ 55 28 59 30 / 20 20 20 20 MORA............................ 54 29 58 34 / 20 20 20 20 ESPANOLA........................ 62 38 66 39 / 10 10 10 10 SANTA FE........................ 57 38 61 41 / 10 10 10 10 SANTA FE AIRPORT................ 63 34 66 36 / 10 10 10 10 ALBUQUERQUE FOOTHILLS........... 65 43 69 46 / 10 5 5 10 ALBUQUERQUE HEIGHTS............. 67 44 71 46 / 5 5 5 5 ALBUQUERQUE VALLEY.............. 68 39 72 41 / 5 5 5 5 ALBUQUERQUE WEST MESA........... 69 41 71 45 / 5 5 5 5 LOS LUNAS....................... 70 36 74 39 / 5 5 5 5 RIO RANCHO...................... 68 42 70 46 / 5 5 5 5 SOCORRO......................... 71 44 75 46 / 10 5 10 5 SANDIA PARK/CEDAR CREST......... 62 38 65 44 / 10 10 10 10 TIJERAS......................... 65 38 67 43 / 10 10 10 10 MORIARTY/ESTANCIA............... 61 29 66 32 / 10 10 10 10 CLINES CORNERS.................. 61 32 63 39 / 10 10 10 10 GRAN QUIVIRA.................... 63 39 66 42 / 10 10 10 10 CARRIZOZO....................... 68 44 70 46 / 10 10 5 5 RUIDOSO......................... 65 37 65 43 / 10 10 5 5 CAPULIN......................... 48 30 55 35 / 40 30 30 30 RATON........................... 54 28 58 31 / 20 40 30 30 SPRINGER........................ 55 31 64 35 / 10 50 20 30 LAS VEGAS....................... 57 29 61 37 / 10 20 20 20 CLAYTON......................... 56 33 63 40 / 20 10 20 40 ROY............................. 56 30 63 37 / 5 20 20 30 CONCHAS......................... 63 39 70 44 / 0 5 10 20 SANTA ROSA...................... 64 35 69 43 / 5 5 10 10 TUCUMCARI....................... 66 35 72 43 / 0 5 10 30 CLOVIS.......................... 65 37 68 43 / 0 5 5 20 PORTALES........................ 68 38 70 45 / 0 0 0 20 FORT SUMNER..................... 67 38 70 44 / 0 5 5 10 ROSWELL......................... 71 44 72 45 / 0 5 0 5 PICACHO......................... 68 40 69 44 / 5 10 5 5 ELK............................. 65 38 65 44 / 10 10 5 5 && .ABQ WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 4 PM MDT THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ530. && $$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
735 PM EDT MON APR 20 2015 .SYNOPSIS...A COLD FRONT WILL TRACK EAST ACROSS THE REGION TONIGHT. HIGH PRESSURE WILL BUILD IN FROM THE SOUTHWEST LATE TONIGHT THROUGH TUESDAY... THEN SHIFT OFF THE COAST TUESDAY NIGHT INTO WEDNESDAY. A COLD FRONT WILL APPROACH FROM THE NORTH WEDNESDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 735 PM MONDAY... UPDATE: MODEST PW HAS KEPT COVERAGE FROM GETTING OUT OF HAND SO FAR. WE`RE SEEING PLENTY OF HIGH REFLECTIVITIES IN THE LOWEST 15-20 KFT... HOWEVER CORES ABOVE 25 KFT HAVE BEEN FAIRLY MUTED... AND TOPS HAVE STRUGGLED TO REACH 30-35 KFT. THIS MAY BE A RESULT OF WEAK INSTABILITY ABOVE 25 KFT... NOTED IN THE LATEST RAP SOUNDINGS. NEVERTHELESS... WE`VE STILL MANAGED TO GET VIGOROUS ENOUGH CONVECTION WITH PERSISTENT CELLS POSSESSING LONG-LIVED MESOCYCLONIC CHARACTERISTICS TO GENERATE SEVERAL REPORTS OF DIME TO QUARTER SIZE HAIL. SPC MESOANALYSES STILL HAVE EFFECTIVE DEEP LAYER SHEAR IN EXCESS OF 45 KTS WITH MODEST MLCAPE NEAR 1000 J/KG... STILL INDICATIVE OF POTENTIAL FOR A FEW SEVERE CELLS. WILL RETAIN THE SEVERE THUNDERSTORM WATCH FOR MUCH OF THE PIEDMONT... AND BASED ON THE THIS FAVORABLE AIR MASS EXTENDING INTO THE NE CWA AND ON EXTRAPOLATION OF EXISTING SEVERE AND NEAR-SEVERE STORMS... HAVE ADDED AREAS TO THE WATCH... MAINLY ALONG/NORTH OF A LINE FROM LILLINGTON TO SMITHFIELD TO WILSON. COVERAGE SO FAR HAS BEEN LIMITED TO AREAS FROM RALEIGH TO THE NORTH AND WEST. THE LATEST CONVECTION ALLOWING MODELS SHOW LITTLE TO NO ACTIVITY OVER THE SE CORNER OF THE CWA. HAVE REDUCED POPS IN THE SOUTHEAST FOR THE REMAINDER OF THE NIGHT. -GIH NOW THROUGH THIS EVENING: NUMEROUS SIGNALS CONTINUE TO SUPPORT AN ENHANCED RISK OF SEVERE STORMS IN CENTRAL NC. HEATING/MIXING DISSIPATED THE WEAK CAP OVER THE REGION NEARLY 2 HOURS AGO... YIELDING EXPLOSIVE CONVECTION TO OUR SW OVER NE GA AND UPSTATE SC. SEE NO REASON WHY THIS WON`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
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
622 PM EDT SUN APR 19 2015 .SYNOPSIS... A FRONTAL SYSTEM WILL BRING SHOWERS AND A FEW THUNDERSTORMS THROUGH MONDAY. A FEW STORMS MAY BE STRONG TO SEVERE. DRY AND SEASONABLE HIGH PRESSURE WILL BUILD INTO THE AREA TUESDAY AND WEDNESDAY. WARMER TEMPERATURES ARE EXPECTED THURSDAY AHEAD OF THE NEXT COLD FRONT. MUCH COOLER TEMPERATURES ARE POSSIBLE LATE WEEK AND INTO NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 555 PM SUNDAY...TORNADO WATCH NUMBER 82 THRU 11 PM REMAINS IN EFFECT FOR THE ILM SC CWA...PLUS ROBESON COUNTY OF THE ILM NC CWA. BROKEN LINE OF STRONG TO SEVERE THUNDERSTORMS IS ON THE WESTERN DOORSTEPS OF THE ILM CWA AT THE MOMENT. POPS HAVE BEEN RE-ADJUSTED THRUOUT THIS EVENING TO TAKE INTO ACCOUNT OF THE TIMING AND PROGRESSION OF THIS LINE AS IT TRAVERSES THE ILM CWA. AT THIS POINT...THE CUMULATIVE THINKING IS THAT THE CONVECTION WILL WEAKEN TO BELOW SEVERE LIMITS BY THE TIME IT PROGRESSES ACROSS THE ILM NC COUNTIES LATER THIS EVENING AND OVERNIGHT AND THEREFORE A WATCH IS WAS NOT PLANNED AT THIS TIME. PREVIOUS........................................................ AS OF 315 PM SUNDAY...AS LIGHT STRATIFORM RAINFALL PULLS NE AWAY FROM THE REGION THIS AFTERNOON...A MORE ORGANIZED BAND OF SHOWERS AND TSTMS WILL MOVE INTO NE SC 6 PM - 7 PM...AND INTO SE NC IN THE MIDDLE AND LATE EVENING. THIS IS APT TO BRING SIGNIFICANTLY MORE RAINFALL AMOUNTS TO THE AREA TONIGHT. SATELLITE DERIVED SENSORS OF PRECIPITABLE WATERS SHOW A LARGE SWATH OF 46MM/1.81 INCH PWATS MOVING INTO THE AREA THAT WILL HELP FUEL THE CONVECTION. SEVERAL ISOLATED OR DISCREET CELLS MAY ALSO FIRE AHEAD OF THE ORGANIZED RAIN AREA AFTER THE STRATIFORM RAIN HAS CLEARED. SEVERAL RECENT NEAR TERM MODELS SHOWS THE BULK OF RAINFALL MOVING NE OF SE NC AFTER 5Z/1AM. THE ORGANIZED NATURE OF THIS FEATURE IF HELD INTACT WILL INTRODUCE A SLIGHT CHANCE OF WIND DAMAGE OR HAIL TONIGHT. MINIMUMS TONIGHT WILL NOT FALL MUCH BELOW THE MIDDLE 60S EVEN IN RAIN COOLED LOCATIONS AS DEWPOINTS REMAIN ELEVATED. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...THE CWA WILL BE IN A RATHER WARM AND BLUSTERY SOUTHWEST FLOW AT THE BEGINNING OF THE PERIOD...IN BETWEEN A DEPARTING WARM FRONT TO THE NORTHEAST AND A COLD FRONT ACROSS THE TENNESSEE VALLEY. THIS FRONT MOVES STEADILY ACROSS THE SOUTHEAST DURING THE DAY AND SHOULD BE JUST ACROSS OUR WESTERN COUNTIES BY 0000 UTC TUESDAY. SEVERE PARAMETERS STILL LOOK CONDUCIVE FOR AN EVENT WITH ADEQUATE INSTABILITY AND SHEAR. HOWEVER HIGH RESOLUTION GUIDANCE IS SHOWING A LACK OF ACTIVITY WITH THE FRONT. THE MET HAS SIX HOUR POPS IN THE SINGLE DIGITS FOR THE 18-00 UTC TIME FRAME IN LBT AND ILM. THE GFS REMAINS MORE BULLISH WITH SCATTERED ACTIVITY AHEAD OF A CONVECTIVE LINE. WILL MAINTAIN THE CHANCE POPS AND FINE TUNE FOR THE TIMING FOR LATE AFTERNOON INTO THE EVENING. SPC MAINTAINS THE SLIGHT RISK FOR THE AREA CITING THE UNCERTAINTY. BEYOND THIS HIGH PRESSURE BUILDS IN FOR A NICE TUESDAY AND PEACEFUL WEDNESDAY MORNING. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 PM SUNDAY...HIGH PRESSURE BOTH MOVES OFFSHORE AND WEAKENS CONSIDERABLY. PAIR THIS WITH ZONAL MID FLOW AND THE AFTERNOON SHOULD BE SEASONABLE AND RAIN-FREE WITH A FAIR AMOUNT OF SUNSHINE. THE APPROACH OF A COLD FRONT WILL YIELD A SMALL RISE IN POPS ON THURSDAY OR POSSIBLY EVEN WEDNESDAY NIGHT. THIS SLOW MOVING BOUNDARY MOVES THROUGH ON THURSDAY BUT WILL HAVE TO DEAL WITH MIDLEVEL DOWNSLOPING PREVENTING DEEP MOISTURE. THE FRONT STALLS SOUTH OF THE REGION POSSIBLY CLOSE ENOUGH FOR THE MAINTENANCE OF LOW END POPS. SOME DEEPER MOISTURE AND MORE MEANINGFUL RAIN CHANCES MAY MATERIALIZE OVER THE WEEKEND AS THE FRONT REMAINS TO OUR SOUTH BUT SOME WEAK MID LEVEL IMPULSES WORK TO PROVIDE LIFT ATOP SOME LOW LEVEL ISENTROPIC UPGLIDE. && .AVIATION /22Z SUNDAY THROUGH FRIDAY/... AS OF 18Z...SOME CONVECTION IS TRYING TO MOVE ONSHORE NEAR ILM...OTHERWISE THE COASTAL TERMINALS MAY NOT SEE TOO MUCH ACTION INITIALLY. MAINLY A EAST SOUTHEAST WIND THIS AFTERNOON. THIS EVENING...THE HRRR IS STAYING FAIRLY CONSISTENT IN BRINGING IN AN ORGANIZED LINE OF OF CONVECTION TO THE INLAND TERMINALS AROUND 23Z. WILL LEAN HEAVILY ON THIS MODEL THROUGH THE EVENING HOURS. AFTER THE CONVECTION MOVES THROUGH...EXPECT IFR CEILING THROUGH THE OVERNIGHT HOURS...WITH SOME LIGHT FOG. MONDAY...IMPROVING CEILINGS AS THE DAY WEARS ON WITH A GUSTY SOUTHWEST WIND. CONVECTION IS EXPECTED TO FIRE AFTER THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...A COLD FRONT WILL PUSH THROUGH THE AREA MONDAY NIGHT WITH SHOWERS POSSIBLE FOLLOWED BY MAINLY VFR CONDITIONS TUESDAY AND WEDNESDAY. POSSIBLE SHOWERS THURSDAY AND FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 555 PM SUNDAY...TOR WATCH 82 AFFECTS THE ILM SC WATERS THRU 11 PM. THE MARINE BOUNDARY LAYER OVER THE COOLER SHELF WATERS WILL ACT TO WEAKEN CONVECTION AS IT REACHES AND MOVES ACROSS ALL WATERS DURING THIS EVENING. THE STRONGER STORMS THIS EVENING THAT AFFECT THE ILM SC WATERS COULD PRODUCE SMW CRITERIA BRIEF GALE FORCE WIND GUSTS OR WATERSPOUTS. OTHERWISE...THE MAJORITY OF THE CONVECTION WILL PRODUCE MWS CRITERIA WINDS AND LIGHTNING. PREVIOUS........................................................ AS OF 315 PM SUNDAY...SEAS SLOWLY ON THE RISE IN THE MODERATE ONSHORE WIND FLOW AND 3-5 FOOT SEAS EXPECTED OVERNIGHT. SEVERAL TSTMS ARRIVING FROM THE SW TONIGHT MAY PRODUCE LOCALLY HIGHER WINDS AND SEAS...AND SEVERAL SPECIAL MARINE WARNINGS MAY BE NEEDED FOR TONIGHT WITH CLOUD TO SEA LIGHTNING POSING AN ADDITIONAL HAZARD. WINDS WILL VEER TO S AND SW OVERNIGHT WHICH WILL HELP TO LIMIT WAVE GROWTH AND A SMALL CRAFT ADVISORY IS NOT PLANNED ALTHOUGH AN EXERCISE CAUTION STATEMENT COULD BE NEEDED. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...A SOUTHWEST FLOW OF 10-15 KNOTS INITIALLY WILL INCREASE TO 15-20 BY THE END OF THE DAY MONDAY AS A FRONT MOVES CLOSER FROM THE WEST. THE FRONT FINALLY CROSSES THE WATERS EARLY TUESDAY MORNING WITH A MODEST WESTERLY FLOW OF 10-15 KNOTS IN ITS WAKE. SMOOTH SAILING FOR THE REMAINDER OF THE PERIOD WITH WINDS TEN KNOTS OR LESS FROM THE WEST NORTHWEST AND SEAS OF 2-4 FEET. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 300 PM SUNDAY...WEDNESDAY BRINGS NEARLY MINIMAL WIND AND SEAS DUE TO HIGH PRESSURE MOVING OVERHEAD. WINDS THOUGH LIGHT WILL VEER CONSIDERABLY AS THE DAY PROGRESSES UNTIL A S TO SW FLOW BECOMES PREDOMINANT LATE IN THE DAY OR AT NIGHT. MORE VEERING IS SLATED FOR THURSDAY AS A COLD FRONT APPROACHES AND VERY SLOWLY CROSSES THE WATERS. WITH THIS FRONT STALLING NEARBY TO OUR SOUTH ON FRIDAY A LIGHT NORTHERLY FLOW WILL BE MAINTAINED. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...DCH/MJC SHORT TERM...SHK LONG TERM...MBB AVIATION...MJC/SHK/DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
319 PM EDT SUN APR 19 2015 .SYNOPSIS... A FRONTAL SYSTEM WILL BRING SHOWERS AND A FEW THUNDERSTORMS THROUGH MONDAY. A FEW STORMS MAY BE STRONG TO SEVERE. DRY AND SEASONABLE HIGH PRESSURE WILL BUILD INTO THE AREA TUESDAY AND WEDNESDAY. WARMER TEMPERATURES ARE EXPECTED THURSDAY AHEAD OF THE NEXT COLD FRONT. MUCH COOLER TEMPERATURES ARE POSSIBLE LATE WEEK AND INTO NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 315 PM SUNDAY...AS LIGHT STRATIFORM RAINFALL PULLS NE AWAY FROM THE REGION THIS AFTERNOON...A MORE ORGANIZED BAND OF SHOWERS AND TSTMS WILL MOVE INTO NE SC 6 PM - 7 PM...AND INTO SE NC IN THE MIDDLE AND LATE EVENING. THIS IS APT TO BRING SIGNIFICANTLY MORE RAINFALL AMOUNTS TO THE AREA TONIGHT. SATELLITE DERIVED SENSORS OF PRECIPITABLE WATERS SHOW A LARGE SWATH OF 46MM/1.81 INCH PWATS MOVING INTO THE AREA THAT WILL HELP FUEL THE CONVECTION. SEVERAL ISOLATED OR DISCREET CELLS MAY ALSO FIRE AHEAD OF THE ORGANIZED RAIN AREA AFTER THE STRATIFORM RAIN HAS CLEARED. SEVERAL RECENT NEAR TERM MODELS SHOWS THE BULK OF RAINFALL MOVING NE OF SE NC AFTER 5Z/1AM. THE ORGANIZED NATURE OF THIS FEATURE IF HELD INTACT WILL INTRODUCE A SLIGHT CHANCE OF WIND DAMAGE OR HAIL TONIGHT. MINIMUMS TONIGHT WILL NOT FALL MUCH BELOW THE MIDDLE 60S EVEN IN RAIN COOLED LOCATIONS AS DEWPOINTS REMAIN ELEVATED. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...THE CWA WILL BE IN A RATHER WARM AND BLUSTERY SOUTHWEST FLOW AT THE BEGINNING OF THE PERIOD...IN BETWEEN A DEPARTING WARM FRONT TO THE NORTHEAST AND A COLD FRONT ACROSS THE TENNESSEE VALLEY. THIS FRONT MOVES STEADILY ACROSS THE SOUTHEAST DURING THE DAY AND SHOULD BE JUST ACROSS OUR WESTERN COUNTIES BY 0000 UTC TUESDAY. SEVERE PARAMETERS STILL LOOK CONDUCIVE FOR AN EVENT WITH ADEQUATE INSTABILITY AND SHEAR. HOWEVE HIGH RESOLUTION GUIDANCE IS SHOWING A LACK OF ACVITITY WITH THE FRONT. THE MET HAS SIX HOUR POPS IN THE SINGLE DIGITS FOR THE 18-00 UTC TIME FRAME IN LBT AND ILM. THE GFS REMAINS MORE BULLISH WITH SCATTERED ACTIVITY AHEAD OF A CONVECTIVE LINE. WILL MAINTAIN THE CHANCE POPS AND FINE TUNE FOR THE TIMING FOR LATE AFTERNOON INTO THE EVENING. SPC MAINTAINS THE SLIGHT RISK FOR THE AREA CITING THE UNCERTAINTY. BEYOND THIS HIGH PRESSURE BUILDS IN FOR A NICE TUESDAY AND PEACEFUL WEDNESDAY MORNING. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 PM SUNDAY...HIGH PRESSURE BOTH MOVES OFFSHORE AND WEAKENS CONSIDERABLY. PAIR THIS WITH ZONAL MID FLOW AND THE AFTERNOON SHOULD BE SEASONABLE AND RAIN-FREE WITH A FAIR AMOUNT OF SUNSHINE. THE APPROACH OF A COLD FRONT WILL YIELD A SMALL RISE IN POPS ON THURSDAY OR POSSIBLY EVEN WEDNESDAY NIGHT. THIS SLOW MOVING BOUNDARY MOVES THROUGH ON THURSDAY BUT WILL HAVE TO DEAL WITH MIDLEVEL DOWNSLOPING PREVENTING DEEP MOISTURE. THE FRONT STALLS SOUTH OF THE REGION POSSIBLY CLOSE ENOUGH FOR THE MAINTENANCE OF LOW END POPS. SOME DEEPER MOISTURE AND MORE MEANINGFUL RAIN CHANCES MAY MATERIALIZE OVER THE WEEKEND AS THE FRONT REMAINS TO OUR SOUTH BUT SOME WEAK MID LEVEL IMPULSES WORK TO PROVIDE LIFT ATOP SOME LOW LEVEL ISENTROPIC UPGLIDE. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... AS OF 18Z...SOME CONVECTION IS TRYING TO MOVE ONSHORE NEAR ILM...OTHERWISE THE COASTAL TERMINALS MAY NOT SEE TOO MUCH ACTION INITIALLY. MAINLY A EAST SOUTHEAST WIND THIS AFTERNOON. THIS EVENING...THE HRRR IS STAYING FAIRLY CONSISTENT IN BRINGING IN AN ORGANIZED LINE OF OF CONVECTION TO THE INLAND TERMINALS AROUND 23Z. WILL LEAN HEAVILY ON THIS MODEL THROUGH THE EVENING HOURS. AFTER THE CONVECTION MOVES THROUGH...EXPECT IFR CEILING THROUGH THE OVERNIGHT HOURS...WITH SOME LIGHT FOG. MONDAY...IMPROVING CEILINGS AS THE DAY WEARS ON WITH A GUSTY SOUTHWEST WIND. CONVECTION IS EXPECTED TO FIRE AFTER THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...A COLD FRONT WILL PUSH THROUGH THE AREA MONDAY NIGHT WITH SHOWERS POSSIBLE FOLLOWED BY MAINLY VFR CONDITIONS TUESDAY AND WEDNESDAY. POSSIBLE SHOWERS THURSDAY AND FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 315 PM SUNDAY...SEAS SLOWLY ON THE RISE IN THE MODERATE ONSHORE WIND FLOW AND 3-5 FOOT SEAS EXPECTED OVERNIGHT. SEVERAL TSTMS ARRIVING FROM THE SW TONIGHT MAY PRODUCE LOCALLY HIGHER WINDS AND SEAS...AND SEVERAL SPECIAL MARINE WARNINGS MAY BE NEEDED FOR TONIGHT WITH CLOUD TO SEA LIGHTNING POSING AN ADDITIONAL HAZARD. WINDS WILL VEER TO S AND SW OVERNIGHT WHICH WILL HELP TO LIMIT WAVE GROWTH AND A SMALL CRAFT ADVISORY IS NOT PLANNED ALTHOUGH AN EXERCISE CAUTION STATEMENT COULD BE NEEDED. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...A SOUTHWEST FLOW OF 10-15 KNOTS INITIALLY WILL INCREASE TO 15-20 BY THE END OF THE DAY MONDAY AS A FRONT MOVES CLOSER FROM THE WEST. THE FRONT FINALLY CROSSES THE WATERS EARLY TUESDAY MORNING WITH A MODEST WESTERLY FLOW OF 10-15 KNOTS IN ITS WAKE. SMOOTH SAILING FOR THE REMAINDER OF THE PERIOD WITH WINDS TEN KNOTS OR LESS FROM THE WEST NORTHWEST AND SEAS OF 2-4 FEET. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 300 PM SUNDAY...WEDNESDAY BRINGS NEARLY MINIMAL WIND AND SEAS DUE TO HIGH PRESSURE MOVING OVERHEAD. WINDS THOUGH LIGHT WILL VEER CONSIDERABLY AS THE DAY PROGRESSES UNTIL A S TO SW FLOW BECOMES PREDOMINANT LATE IN THE DAY OR AT NIGHT. MORE VEERING IS SLATED FOR THURSDAY AS A COLD FRONT APPROACHES AND VERY SLOWLY CROSSES THE WATERS. WITH THIS FRONT STALLING NEARBY TO OUR SOUTH ON FRIDAY A LIGHT NORTHERLY FLOW WILL BE MAINTAINED. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...MJC SHORT TERM...SHK LONG TERM...MBB AVIATION...DL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
201 PM EDT SUN APR 19 2015 .SYNOPSIS... HIGH PRESSURE EXTENDING OVER THE AREA FROM THE NORTH WILL SHIFT OFFSHORE TODAY. A WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA TONIGHT AS LOW PRESSURE MOVES INTO THE OHIO VALLEY. A COLD FRONT WILL MOVE THROUGH FROM THE WEST EARLY TUESDAY FOLLOWED BY HIGH PRESSURE WEDNESDAY. ANOTHER COLD FRONT WILL MOVE IN FROM THE NORTHWEST THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 110 PM SUNDAY...FORECAST PRETTY MUCH ON TRACK WITH A MODERATE TO HEAVY SHOWERS DRIFTING IN FROM THE OCEAN AND THE LEADING EDGE OF THE WIDESPREAD RAIN SHIELD IS MOVING INTO SOUTH CENTRAL NORTH CAROLINA. GENERALLY FOLLOWED THE 3KM HRRR WHICH IS DOING A GOOD JOB OF DEPICTING THE RAINFALL. NO CHANGES THROUGH THE AFTERNOON AS RAIN BECOMES WIDESPREAD AND STEADY. CONVECTIVE DEVELOPMENT POTENTIAL SEEMS LIMITED BASED ON CURRENT PARAMETERS AS BEST INSTABILITY OCCURRING MUCH FURTHER SOUTHWEST ACROSS GEORGIA...ALABAMA AND THE FLORIDA PANHANDLE. NO CHANGE TO TEMPERATURE FORECAST. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... AS OF 400 AM SUNDAY...LATEST GDNC CONTINUES TO INDICATE WET CONDITIONS TONIGHT AND INCREASED POPS TO 100% ALL ZONES. DIFFLUENT UPR FLOW AHEAD OF UPR TROF LIFTING OUT OF SRN PLAINS WILL INDUCE LARGE SCALE ASCENT ACROSS AREA ALONG WITH DEEP MSTR PLUME FROM GULFMEX. SFC WARM FRONT WILL APPROACH FROM SW AS DEVELOPING LOW PRES MOVES INTO WRN OH VLY. WDSPRD SHOWERS AND PSBLY SCT TSTMS EXPECTED TO GRADUALLY SPREAD SW TO NE ACROSS ERN NC OVERNIGHT. QPF LOWERED SLIGHTLY BASED ON HPC AND LATEST MODEL BLEND...BUT MOST AREAS STILL SEEING 1/2 TO 1 INCH. PER NEAR-TERM...MARGINAL SVR THREAT FOR SW SECTIONS WITH SOME POTENTIAL FOR ROTATING STORMS ALONG AND AHEAD OF WARM FRONT. GENERALLY A HIGH SHEAR/LOW CAPE THREAT WITH WDSPRD CLOUDS AND PCPN LIMITING INSTABILITY. MIN TEMPS MAINLY LOW-MID 60S EVEN WITH WDSPRD RAIN. && .LONG TERM /MONDAY THROUGH SATURDAY/... AS OF 350 AM SUNDAY...BY MONDAY, THE UPPER TROUGH WILL SHIFT EAST NEAR THE GREAT LAKES REGION WITH SEVERAL SHORTWAVES/ VORTICITY MAXIMA ROTATING AROUND THE BASE OF THE UPPER TROUGH. THE SURFACE LOW WILL MOVE NORTHEAST INTO SOUTHEASTERN CANADA WITH THE ATTENDANT COLD FRONT WELL NORTH OF THE REGION. THE BEST LIFT FROM THE NORTHERN STREAM LIFTS WELL NORTH OF THE AREA WHILE THE SOUTHERN STREAM JET REMAINS WELL SOUTHWEST OF EASTERN NC. THE BEST MOISTURE ALSO LIFTS WELL NORTH OF EASTERN NC WITH FORECAST SOUNDINGS INDICATING PWATS FALLING TO 1.20 INCHES MONDAY AFTERNOON. GUIDANCE IS IN GOOD AGREEMENT WITH A SHORTWAVE/VORT MAX MOVING THROUGH EASTERN NC MONDAY AFTERNOON/EVENING WHICH COULD HELP SUPPORT OR ENHANCE ONGOING CONVECTION. 500 MB TEMPS FALL FROM AROUND -11/-12 C SUNDAY TO -15/-16 C MONDAY AFTERNOON INDICATING A FAVORABLE ENVIRONMENT FOR LARGE HAIL SHOULD STORMS BECOME SEVERE. GIVEN SOUTHWESTERLY UNIDIRECTIONAL SHEAR, CAN ALSO EXPECT A FEW SHOWERS/THUNDERSTORMS ALONG THE INLAND MOVING SEA- BREEZE. AS DRY SLOTTING DEVELOPS MONDAY MORNING, CLOUD COVER WILL DIMINISH ALLOWING EXCELLENT INSOLATION. INSTABILITY WILL BE PLENTIFUL THOUGH THE ENVIRONMENT WILL A TRIGGER FOR CONVECTIVE INITIATION, AND LACK VEERING LOW LEVEL WINDS. SPC MAINTAINS A SLIGHT RISK FOR EASTERN NC THROUGH MONDAY EVENING/NIGHT. BIGGEST THREAT WILL BE LARGE HAIL AND DAMAGING WIND GUSTS, THOUGH AN ISOLATED TORNADO CANNOT BE RULED OUT. INCREASED POPS TO CHANCE INLAND MONDAY AFTERNOON. HIGHS MONDAY WILL BE IN THE LOW 80S INLAND AND MID 70S BEACHES. MONDAY NIGHT/TUESDAY...COLD FRONT MOVES OFFSHORE LATE MONDAY NIGHT AND EARLY TUESDAY MORNING WITH SLIGHTLY COOLER AND DRIER AIR MOVING IN. TUESDAY`S HIGHS SHOULD BE IN THE MID 70S...BUT WITH DEWPOINTS DOWN IN THE LOWER 50S BY AFTERNOON. TUESDAY NIGHT/WEDNESDAY...HIGH PRESSURE BUILDS OVERHEAD WITH MAINLY HIGH CLOUDS WEDNESDAY. COOL MORNING LOWS AROUND 50 REBOUND TO AFTERNOON HIGHS IN THE MID 70S. WEDNESDAY NIGHT/THURSDAY...ZONAL FLOW ALOFT CONTINUES AS A COLD FRONT CROSSES THE REGION LATE THURSDAY. GUIDANCE IN MODEST AGREEMENT FOR LIGHT SHOWERS/THUNDERSTORMS THURSDAY, THUS HAVE INTRODUCED SLIGHT CHANCE POP WITH FRONTAL PASSAGE. ANOTHER COOL MORNING THURSDAY WITH LOWS 50 TO 55...REBOUNDING INTO THE UPPER 70S THURSDAY AFTERNOON. THURSDAY NIGHT/FRIDAY...DRY WEATHER BEHIND THE FRONT WITH SUNNY COOLER WEATHER FOR FRIDAY. LOWS AGAIN IN THE 50 TO 55 DEGREE RANGE WITH HIGHS UPPER 60S FAR NORTHEAST AND LOW 70S ELSEWHERE. FRIDAY NIGHT/SATURDAY...ANOTHER SOUTHERN STREAM SYSTEM APPROACHES LATE SATURDAY. HAVE INDICATED INCREASED CLOUD COVER AND A SMALL CHANCE OF RAIN IN THE AFTERNOON. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... SHORT TERM /THROUGH 18Z MONDAY/... AS OF 140 PM SUNDAY...VFR CONDITIONS WILL PERSIST FOR ANOTHER ONE TO TWO HOURS...BEFORE CONDITIONS BEGIN TO DETERIORATE THIS AFTERNOON. SE WINDS WILL CONTINUE THROUGH THIS EVENING AT 10 TO 15 KNOTS. WIDESPREAD SHOWERS WILL SPREAD FROM THE SW TO NE THIS AFTERNOON WITH A SLIGHT CHANCE OF THUNDERSTORMS THROUGH LATE THIS EVENING. GUIDANCE AND MODEL SOUNDING ARE SHOWING WIDESPREAD IFR CONDITIONS FOR ALL TAF SITES SHORTLY AFTER 00Z. IFR CONDITIONS WILL PERSIST THROUGH THE OVERNIGHT UNDER WIDESPREAD RAIN SHOWERS. CONDITIONS WILL IMPROVE BY 12Z MONDAY AS RAIN SHOWERS TAPERS OFF TO THE EAST. EXPECTING VFR CONDITIONS TO RETURN BY 15Z MONDAY UNDER SCT CLOUDS. LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 355 AM SUNDAY...PRECIPITATION DIMINISHES MONDAY BUT SOME ISOLATED STRONG TO SEVERE TSTMS MAY BE POSSIBLE, ESPECIALLY KPGV AND KISO, MONDAY AFTERNOON AND EVENING WHICH COULD PRODUCE SUB-VFR AVIATION CONDITIONS. HIGH PRESSURE BUILDS IN ACROSS EASTERN NC TUESDAY INTO WEDNESDAY YIELDING MOSTLY VFR CONDITIONS. A WEAK FRONT WILL MOVE SOUTH INTO EASTERN NC THURSDAY BUT WITH LIMITED MOISTURE SO EXPECT MOSTLY VFR CONDITIONS THURSDAY. && .MARINE... SHORT TERM /THROUGH TONIGHT/... AS OF 115 PM SUNDAY...WINDS HAVE DROPPED A BIT FROM THIS MORNING WITH GENERALLY E/NE WIND 10 TO 15 KNOTS WITH SOME GUSTS TO AROUND 21 KNOTS AT DIAMOND SHOALS. SEAS STILL 3 TO 5 FEET WITH LONG PERIOD SWELLS OVER THE CENTRAL AND NORTHERN WATERS. WINDS BECOME SE LATER TODAY AS WARM FRONT LIFTS NORTH. WINDS INCREASE TO 15 TO 20 KNOTS BY THIS EVENING. PRES GRAD WILL TIGHTEN TONIGHT WITH WARM FRONT MOVING IN FROM SW...RESULTING IN WINDS BECOMING S-SW 20-25 KT. SEAS BUILDING TO 4-6 FT OUTER WATERS LATE TODAY AND PEAKING 6-8 FT LATE TONIGHT. LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 355 AM SUNDAY...GUSTY S/SW WINDS WILL BUILD SEAS TO 7-8 FEET MONDAY. SEAS WILL REMAIN ELEVATED INTO TUESDAY MORNING AND CURRENT SCA FOR ALL COASTAL WATERS WILL REMAIN IN EFFECT UNTIL 12Z TUESDAY. HIGH PRESSURE WILL BUILD OVER THE NC WATERS TUESDAY INTO WEDNESDAY WITH WINDS SHIFTING MORE WESTERLY, 5-15 KT. SEAS WILL DIMINISH TO 2-4 FT TUESDAY NIGHT THROUGH WEDNESDAY. A COLD FRONT WILL MOVE SOUTH INTO THE NORTHERN WATERS THURSDAY AND SHIFT SOUTH OF THE WATERS THURSDAY NIGHT. WINDS VEER NORTHWEST BEHIND THE FRONT BUT REMAIN 5-15 KT WITH SEAS 2-4 FEET. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 8 AM EDT TUESDAY FOR AMZ150-152-154-156-158. && $$ SYNOPSIS...JBM NEAR TERM...CTC SHORT TERM...JBM LONG TERM...DAG AVIATION...DAG/BM MARINE...CTC/JBM/DAG
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
148 PM EDT SUN APR 19 2015 .SYNOPSIS... A FRONTAL SYSTEM WILL BRING SHOWERS AND A FEW THUNDERSTORMS THROUGH MONDAY. A FEW STORMS MAY BE STRONG TO SEVERE. DRY AND SEASONABLE HIGH PRESSURE WILL BUILD INTO THE AREA TUESDAY AND WEDNESDAY. WARMER TEMPERATURES ARE EXPECTED THURSDAY AHEAD OF THE NEXT COLD FRONT. MUCH COOLER TEMPERATURES ARE POSSIBLE LATE WEEK AND INTO NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1244 PM SUNDAY...NO SIGNIFICANT CHANGES FOR THE EARLY AFTERNOON UPDATE...WITH POP DISTRIBUTION RANGING FROM SCATTERED TO LIKELY ACROSS THE AREA AND A SLIGHT CHANCE OF A THUNDERSTORM. EXTENSIVE CLOUD COVER WILL LIMIT SURFACE BASED BUOYANCY BUT A RAMPING UP IN PRECIPITABLE WATERS AS SEEN IN SATELLITE DATA WILL LIKELY REMOVE ANY CONVECTIVE INHIBITION AND POP-UP SHOWERS COULD OCCUR ANYWHERE NEAR SMALL OUTFLOWS...DIFFERENTIAL HEATING...AND WEAK SEA BREEZE CONVERGENCE ZONES. A BROAD AREA OF PATCHY LIGHT RAIN WILL SPREAD NE ACROSS THE AREA THROUGH THE AFTERNOON. THE PREVIOUS DISCUSSION FOLLOWS. ADJUSTMENTS WERE REQUIRED TO SCALE BACK TIMING AND COVERAGE OF PRECIPITATION TODAY...BASED ON DECLINING NATURE OF SHOWERS ASSOCIATED WITH AN APPROACHING WARM FRONTAL FEATURE. SEVERAL SHOWERS WILL MAKE A RUN TOWARD THE NORTH COAST FROM THE OCEAN...AND AREAS WEST OF I-95 APPEAR POISED TO RECEIVE A TENTH OF AN INCH THROUGH MIDDAY...OTHERWISE PROSPECTS OF SOLID RAIN MEASUREMENTS WERE DECREASED IN THE FORECAST AND THE GRIDDED PRODUCTS THROUGH EARLY AFTERNOON. SOME HOPE REMAINS FOR BREAKS IN THE CLOUD COVER TO OFFER LOW-LEVEL HEATING WHICH COULD INITIATE CONVECTION WITH WEAK SEA BREEZE CONVERGENCE. BETTER RAIN CHANCES APPEAR OVERNIGHT PER SEVERAL OF THE NEAR TERM MODELS. FORECAST FOR TODAY NOW READS SCATTERED EXCEPT FAR WESTERN ZONES LIKELY. DESPITE REDUCTION IN POPS AND TIMING...A FEW TSTMS COULD BECOME STRONG AND SPC MAINTAINS MARGINAL RISK OVER NC AND SLIGHT RISK OVER PORTIONS OF NE SC TODAY. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 AM SUNDAY...INTERESTING START TO THE WORK WEEK AS A SHORTWAVE EMBEDDED WITHIN A DEEPENING TROUGH WILL CREATE THE POTENTIAL FOR STRONG THUNDERSTORMS ON MONDAY. WARM FRONT WILL BE WELL NORTH OF THE AREA MONDAY MORNING...AND MOST OF THE HEAVY RAINFALL ANTICIPATED SUNDAY NIGHT WILL BE NORTH/OFFSHORE BY THE BEGINNING OF THE PERIOD. SOME RESIDUAL SHOWERS MAY PERSIST ON THE COAST EARLY...BUT ACTUALLY EXPECT THE MORNING HOURS TO BE DRY FOR THE MOST PART LOCALLY. THE COLUMN WILL DRY CONSIDERABLY FROM SUNDAY AS THE BEST MOISTURE DEPARTS TO THE NE...AND SOME SUBSIDENCE IS EXPECTED BEHIND AN EXITING SHORTWAVE. THIS WILL LEAVE AT LEAST PARTIAL INSOLATION...AND AS WARM/MOIST ADVECTION CONTINUES THE ATMOSPHERE WILL BECOME QUITE UNSTABLE MONDAY AFTN/EVE. FORECAST MLCAPE VALUES RISE TOWARDS 2000 J/KG...WITH THE SREF MEAN AROUND 1500 J/KG. AT THE SAME TIME...A SHORTWAVE WILL RIDE THROUGH THE DEEPENING TROUGH SO PVA COMBINED WITH HEIGHT FALLS /STEEPENING MID-LEVEL LAPSE RATES/ WILL DRIVE AN ENVIRONMENT CONDUCIVE TO STRONG CONVECTION. ADDITIONALLY...LFQ OF A SUBTROPICAL 250MB JET WILL APPROACH FROM THE SW. HOWEVER...SURFACE FORCING IS MOSTLY WEAK AND THE MID-LEVELS REMAIN QUITE DRY DURING THE MOST UNSTABLE PART OF THE DAY. THIS SUGGESTS THAT ACTIVITY WILL BE ISOLATED OR SCATTERED MONDAY AFTN/EVE...BUT ANY STORM WILL HAVE THE POTENTIAL TO BECOME STRONG AND SPC HAS THE AREA IN A SLIGHT RISK FOR MONDAY. DO NOT EXPECT WIDESPREAD STRONG/SEVERE STORMS...AND ATTM THE BEST FOCUS MAY BE ALONG THE PIEDMONT TROUGH AND WESTERN PORTIONS OF THE CWA. COLD FRONT WILL APPROACH SLOWLY FROM THE NW DRIVEN BY THE DEEPENING UPPER TROUGH...AND IS NOW SLATED FOR A CROSSING JUST BEFORE DAWN TUESDAY. THIS FRONT WILL BE ACCOMPANIED BY MORE WIDESPREAD SHOWER ACTIVITY...BUT NOT EXPECTING STRONG CONVECTION WITH ITS PASSAGE. COLD ADVECTION LAGS THE FRONT CONSIDERABLY...SO WHILE TUESDAY WILL BE DRY WITH MUCH MORE SUNSHINE AS HIGH PRESSURE BUILDS ACROSS THE REGION...TEMPS WILL NOT BE SIGNIFICANTLY COOLER THAN MONDAY. ON THE DISCUSSION OF TEMPERATURES...MONDAY WILL LIKELY BE WELL ABOVE NORMAL WITH WIDESPREAD 80S AWAY FROM THE BEACHES ON STRONG WARM ADVECTION AHEAD OF THE FRONT. A RELATIVELY WARM NIGHT EXPECTED MONDAY NIGHT AS FROPA OCCURS LATE...AND LOWS WILL DROP ONLY INTO THE LOW 60S. SLIGHTLY COOLER TUESDAY WITH HIGHS REACHING WELL INTO THE 70S TO NEAR 80...BEFORE COOL DRY HIGH PRESSURE ALLOWS FOR TEMPS TO CRASH TO AROUND 50 TUESDAY NIGHT. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 300 AM SUNDAY...MID-LEVELS EVOLVE INTO A DECIDEDLY WINTER-LIKE APPEARANCE THROUGH THE EXTENDED WITH A LARGE VORTEX CUTOFF ACROSS SOUTHEAST CANADA WHICH WILL SLOWLY DROP ACROSS NEW ENGLAND BY THE WKND. INITIALLY THIS PRODUCES BENIGN AND SEASONABLE WEATHER ACROSS THE CAROLINAS...AS THE FLOW BECOMES ZONAL BENEATH THE CUTOFF...SO SURFACE HIGH PRESSURE WILL BECOME THE DOMINANT FEATURE WED/THU. THIS HIGH WILL MOVE OFFSHORE THURSDAY AHEAD OF THE NEXT COLD FRONT...DRIVEN BY A PIECE OF VORT ENERGY ROTATING AROUND THE LARGE MID-LEVEL VORTEX. MID-LEVEL FLOW REMAINS W/NW HOWEVER...SO ALTHOUGH PRECIP CHANCES INCREASE WITH THE COLD FRONT...SIGNIFICANT SHOWER ACTIVITY IS NOT ANTICIPATED. THE BIGGER STORY COULD BE MUCH COOLER TEMPS BEHIND THIS FRONT FRI/SAT THANKS TO 1000-500MB THICKNESSES DROPPING TOWARDS -2 SD`S FROM CLIMO...AND HIGHS/LOWS BY SATURDAY COULD FALL WELL BELOW NORMAL. A LOW PRESSURE SYSTEM MAY BEGIN TO EMERGE FROM THE GULF COAST STATES AND MOVE TOWARDS THE AREA AT THE END OF THE PERIOD...AND WILL MAINTAIN INHERITED LOW-CHC POP FOR SATURDAY. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... AS OF 18Z...SOME CONVECTION IS TRYING TO MOVE ONSHORE NEAR ILM...OTHERWISE THE COASTAL TERMINALS MAY NOT SEE TOO MUCH ACTION INITIALLY. MAINLY A EAST SOUTHEAST WIND THIS AFTERNOON. THIS EVENING...THE HRRR IS STAYING FAIRLY CONSISTENT IN BRINGING IN AN ORGANIZED LINE OF OF CONVECTION TO THE INLAND TERMINALS AROUND 23Z. WILL LEAN HEAVILY ON THIS MODEL THROUGH THE EVENING HOURS. AFTER THE CONVECTION MOVES THROUGH...EXPECT IFR CEILING THROUGH THE OVERNIGHT HOURS...WITH SOME LIGHT FOG. MONDAY...IMPROVING CEILINGS AS THE DAY WEARS ON WITH A GUSTY SOUTHWEST WIND. CONVECTION IS EXPECTED TO FIRE AFTER THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...A COLD FRONT WILL PUSH THROUGH THE AREA MONDAY NIGHT WITH SHOWERS POSSIBLE FOLLOWED BY MAINLY VFR CONDITIONS TUESDAY AND WEDNESDAY. POSSIBLE SHOWERS THURSDAY AND FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1244 PM SUNDAY...LOW PRESSURE OVER THE MID-MISSISSIPPI VALLEY WILL DEEPEN TODAY. THE INCREASING SOUTHERLY WIND AHEAD OF THIS SYSTEM WILL DRAG A WARM FRONT THROUGH THE COASTAL CAROLINAS THIS AFTERNOON. GENERALLY EASTERLY WINDS THIS MORNING WILL VEER SOUTHEASTERLY THIS AFTERNOON...THEN SOUTHERLY TONIGHT. WINDS WILL INCREASE BUT NOT EXCESSIVELY SO GIVEN THE PRETTY LARGE DISTANCE FROM HERE BACK TO THE LOW...AND ALSO THE FACT THAT THE INCOMING AIRMASS WILL BE SIGNIFICANTLY WARMER THAN THE OCEAN SURFACE LEADING TO MOST OF THE WIND ENERGY RIDING UP AND OVER A COOL AND STABLE LAYER OF AIR AT THE SURFACE. WIDESPREAD SHOWERS AND EMBEDDED T-STORMS SHOULD AFFECT THE COASTAL WATERS THIS AFTERNOON AND TONIGHT. REDUCED VISIBILITY IN HEAVY RAINFALL AND ALSO OCCASIONAL LIGHTNING STRIKES WILL BE THE MOST SIGNIFICANT IMPACTS. SEAS WILL GRADUALLY BUILD DUE TO THE ONSHORE FLOW...WITH THE WORST CONDITIONS EXPECTED NORTH OF CAPE FEAR. THERE IS A 4-6 HOUR WINDOW LATE THIS EVENING INTO EARLY MONDAY MORNING WHERE A SMALL CRAFT ADVISORY MAY BE NEEDED NORTH OF CAPE FEAR DUE TO 6 FOOT SEAS...BUT GIVEN SOME REMAINING UNCERTAINTY ABOUT HOW LONG SOUTHERLY WINDS BLOW BEFORE VEERING SOUTHWESTERLY AND WEAKENING...I WILL DELAY RAISING THE ADVISORY JUST YET. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 AM SUNDAY...COLD FRONT APPROACHING FROM THE WEST WILL PINCH THE GRADIENT MONDAY...AND GUSTY SW WINDS WILL REACH 15-20 KTS WITH SLIGHTLY HIGHER GUSTS. THIS WILL PERSIST ALL OF MONDAY SINCE THE COLD FRONT IS NOT EXPECTED TO CROSS OFFSHORE UNTIL FIRST LIGHT TUESDAY...AND THUS A CHOPPY SEA STATE IS EXPECTED. WAVE HEIGHTS WILL RISE TO 4-5 FT...AND A SCEC MAY BE NEEDED MUCH OF MONDAY. WINDS WILL SHIFT QUICKLY TO THE W AND THEN NW BEHIND THE FRONT TUESDAY MORNING...AND THEN SLOWLY DECREASE IN SPEED FROM 10-15 KTS...TO AROUND 5 KTS AS HIGH PRESSURE BUILDS TOWARDS THE AREA REDUCING THE PRESSURE GRADIENT. SEAS WILL FALL INITIALLY ON THE OFFSHORE WIND TO 2-4 FT...BEFORE DROPPING FURTHER TO 1-2 FT TUESDAY NIGHT. LONG TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 300 AM SUNDAY...BROAD HIGH PRESSURE WILL SKIRT ACROSS THE WATERS AND OFFSHORE WEDNESDAY...SO LIGHT AND VARIABLE WINDS WILL GRADUALLY TRANSITION TO A SW DIRECTION WEDNESDAY NIGHT AS RETURN FLOW DEVELOPS. THIS SW FLOW WILL PERSIST MOST OF THURSDAY BUT WITH SPEEDS INCREASING TO 10-15 KTS AHEAD OF A COLD FRONT WHICH WILL CROSS THE WATERS AT THE END OF THE PERIOD. WAVE HEIGHTS OF 1-2 FT WILL BUILD SLOWLY ONCE THE WIND BECOMES PREDOMINANTLY FROM THE SW LATE WEDNESDAY...AND THEN CONTINUE TO SLOWLY RISE THURSDAY TO 3-4 FT BEFORE THE COLD FRONTAL PASSAGE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...MJC SHORT TERM...JDW LONG TERM...JDW AVIATION...DL MARINE...TRA/JDW
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
117 PM EDT SUN APR 19 2015 .SYNOPSIS... HIGH PRESSURE EXTENDING OVER THE AREA FROM THE NORTH WILL SHIFT OFFSHORE TODAY. A WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA TONIGHT AS LOW PRESSURE MOVES INTO THE OHIO VALLEY. A COLD FRONT WILL MOVE THROUGH FROM THE WEST EARLY TUESDAY FOLLOWED BY HIGH PRESSURE WEDNESDAY. ANOTHER COLD FRONT WILL MOVE IN FROM THE NORTHWEST THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 110 PM SUNDAY...FORECAST PRETTY MUCH ON TRACK WITH A MODERATE TO HEAVY SHOWERS DRIFTING IN FROM THE OCEAN AND THE LEADING EDGE OF THE WIDESPREAD RAIN SHIELD IS MOVING INTO SOUTH CENTRAL NORTH CAROLINA. GENERALLY FOLLOWED THE 3KM HRRR WHICH IS DOING A GOOD JOB OF DEPICTING THE RAINFALL. NO CHANGES THROUGH THE AFTERNOON AS RAIN BECOMES WIDESPREAD AND STEADY. CONVECTIVE DEVELOPMENT POTENTIAL SEEMS LIMITED BASED ON CURRENT PARAMETERS AS BEST INSTABILITY OCCURRING MUCH FURTHER SOUTHWEST ACROSS GEORGIA...ALABAMA AND THE FLORIDA PANHANDLE. NO CHANGE TO TEMPERATURE FORECAST. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... AS OF 400 AM SUNDAY...LATEST GDNC CONTINUES TO INDICATE WET CONDITIONS TONIGHT AND INCREASED POPS TO 100% ALL ZONES. DIFFLUENT UPR FLOW AHEAD OF UPR TROF LIFTING OUT OF SRN PLAINS WILL INDUCE LARGE SCALE ASCENT ACROSS AREA ALONG WITH DEEP MSTR PLUME FROM GULFMEX. SFC WARM FRONT WILL APPROACH FROM SW AS DEVELOPING LOW PRES MOVES INTO WRN OH VLY. WDSPRD SHOWERS AND PSBLY SCT TSTMS EXPECTED TO GRADUALLY SPREAD SW TO NE ACROSS ERN NC OVERNIGHT. QPF LOWERED SLIGHTLY BASED ON HPC AND LATEST MODEL BLEND...BUT MOST AREAS STILL SEEING 1/2 TO 1 INCH. PER NEAR-TERM...MARGINAL SVR THREAT FOR SW SECTIONS WITH SOME POTENTIAL FOR ROTATING STORMS ALONG AND AHEAD OF WARM FRONT. GENERALLY A HIGH SHEAR/LOW CAPE THREAT WITH WDSPRD CLOUDS AND PCPN LIMITING INSTABILITY. MIN TEMPS MAINLY LOW-MID 60S EVEN WITH WDSPRD RAIN. && .LONG TERM /MONDAY THROUGH SATURDAY/... AS OF 350 AM SUNDAY...BY MONDAY, THE UPPER TROUGH WILL SHIFT EAST NEAR THE GREAT LAKES REGION WITH SEVERAL SHORTWAVES/ VORTICITY MAXIMA ROTATING AROUND THE BASE OF THE UPPER TROUGH. THE SURFACE LOW WILL MOVE NORTHEAST INTO SOUTHEASTERN CANADA WITH THE ATTENDANT COLD FRONT WELL NORTH OF THE REGION. THE BEST LIFT FROM THE NORTHERN STREAM LIFTS WELL NORTH OF THE AREA WHILE THE SOUTHERN STREAM JET REMAINS WELL SOUTHWEST OF EASTERN NC. THE BEST MOISTURE ALSO LIFTS WELL NORTH OF EASTERN NC WITH FORECAST SOUNDINGS INDICATING PWATS FALLING TO 1.20 INCHES MONDAY AFTERNOON. GUIDANCE IS IN GOOD AGREEMENT WITH A SHORTWAVE/VORT MAX MOVING THROUGH EASTERN NC MONDAY AFTERNOON/EVENING WHICH COULD HELP SUPPORT OR ENHANCE ONGOING CONVECTION. 500 MB TEMPS FALL FROM AROUND -11/-12 C SUNDAY TO -15/-16 C MONDAY AFTERNOON INDICATING A FAVORABLE ENVIRONMENT FOR LARGE HAIL SHOULD STORMS BECOME SEVERE. GIVEN SOUTHWESTERLY UNIDIRECTIONAL SHEAR, CAN ALSO EXPECT A FEW SHOWERS/THUNDERSTORMS ALONG THE INLAND MOVING SEA- BREEZE. AS DRY SLOTTING DEVELOPS MONDAY MORNING, CLOUD COVER WILL DIMINISH ALLOWING EXCELLENT INSOLATION. INSTABILITY WILL BE PLENTIFUL THOUGH THE ENVIRONMENT WILL A TRIGGER FOR CONVECTIVE INITIATION, AND LACK VEERING LOW LEVEL WINDS. SPC MAINTAINS A SLIGHT RISK FOR EASTERN NC THROUGH MONDAY EVENING/NIGHT. BIGGEST THREAT WILL BE LARGE HAIL AND DAMAGING WIND GUSTS, THOUGH AN ISOLATED TORNADO CANNOT BE RULED OUT. INCREASED POPS TO CHANCE INLAND MONDAY AFTERNOON. HIGHS MONDAY WILL BE IN THE LOW 80S INLAND AND MID 70S BEACHES. MONDAY NIGHT/TUESDAY...COLD FRONT MOVES OFFSHORE LATE MONDAY NIGHT AND EARLY TUESDAY MORNING WITH SLIGHTLY COOLER AND DRIER AIR MOVING IN. TUESDAY`S HIGHS SHOULD BE IN THE MID 70S...BUT WITH DEWPOINTS DOWN IN THE LOWER 50S BY AFTERNOON. TUESDAY NIGHT/WEDNESDAY...HIGH PRESSURE BUILDS OVERHEAD WITH MAINLY HIGH CLOUDS WEDNESDAY. COOL MORNING LOWS AROUND 50 REBOUND TO AFTERNOON HIGHS IN THE MID 70S. WEDNESDAY NIGHT/THURSDAY...ZONAL FLOW ALOFT CONTINUES AS A COLD FRONT CROSSES THE REGION LATE THURSDAY. GUIDANCE IN MODEST AGREEMENT FOR LIGHT SHOWERS/THUNDERSTORMS THURSDAY, THUS HAVE INTRODUCED SLIGHT CHANCE POP WITH FRONTAL PASSAGE. ANOTHER COOL MORNING THURSDAY WITH LOWS 50 TO 55...REBOUNDING INTO THE UPPER 70S THURSDAY AFTERNOON. THURSDAY NIGHT/FRIDAY...DRY WEATHER BEHIND THE FRONT WITH SUNNY COOLER WEATHER FOR FRIDAY. LOWS AGAIN IN THE 50 TO 55 DEGREE RANGE WITH HIGHS UPPER 60S FAR NORTHEAST AND LOW 70S ELSEWHERE. FRIDAY NIGHT/SATURDAY...ANOTHER SOUTHERN STREAM SYSTEM APPROACHES LATE SATURDAY. HAVE INDICATED INCREASED CLOUD COVER AND A SMALL CHANCE OF RAIN IN THE AFTERNOON. && .AVIATION /17Z SUNDAY THROUGH THURSDAY/... SHORT TERM /THROUGH 12Z MONDAY/... AS OF 700 AM SUNDAY...LIFT STRATUS CIGS DEVELOPED ALL TAF SITES 10-11Z WITH LIFR VSBYS AS WELL AT KPGV AND KISO. CONDITIONS EXPECTED TO LIFT TO VFR BY AROUND 13Z. VFR PERSISTING INTO EARLY AFTN...THEN CONDITIONS DETERIORATING. WIDESPREAD SHOWERS/ISOLD TSTMS EXPECTED TO DEVELOP AND SPREAD SW TO NE ACROSS AREA THIS AFTN INTO EARLY EVENING...WITH WDSPRD IFR CIGS LIKELY ALL TAF SITES BY 00Z AND PERSISTING OVERNIGHT WITH VSBYS 3-5 SM IN SHRA. LIGHT WINDS THIS MORNING WILL BECOME SE 10-15 KT THIS AFTN INTO EVENING. LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 355 AM SUNDAY...PRECIPITATION DIMINISHES MONDAY BUT SOME ISOLATED STRONG TO SEVERE TSTMS MAY BE POSSIBLE, ESPECIALLY KPGV AND KISO, MONDAY AFTERNOON AND EVENING WHICH COULD PRODUCE SUB-VFR AVIATION CONDITIONS. HIGH PRESSURE BUILDS IN ACROSS EASTERN NC TUESDAY INTO WEDNESDAY YIELDING MOSTLY VFR CONDITIONS. A WEAK FRONT WILL MOVE SOUTH INTO EASTERN NC THURSDAY BUT WITH LIMITED MOISTURE SO EXPECT MOSTLY VFR CONDITIONS THURSDAY. && .MARINE... SHORT TERM /THROUGH TONIGHT/... AS OF 115 PM SUNDAY...WINDS HAVE DROPPED A BIT FROM THIS MORNING WITH GENERALLY E/NE WIND 10 TO 15 KNOTS WITH SOME GUSTS TO AROUND 21 KNOTS AT DIAMOND SHOALS. SEAS STILL 3 TO 5 FEET WITH LONG PERIOD SWELLS OVER THE CENTRAL AND NORTHERN WATERS. WINDS BECOME SE LATER TODAY AS WARM FRONT LIFTS NORTH. WINDS INCREASE TO 15 TO 20 KNOTS BY THIS EVENING. PRES GRAD WILL TIGHTEN TONIGHT WITH WARM FRONT MOVING IN FROM SW...RESULTING IN WINDS BECOMING S-SW 20-25 KT. SEAS BUILDING TO 4-6 FT OUTER WATERS LATE TODAY AND PEAKING 6-8 FT LATE TONIGHT. LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 355 AM SUNDAY...GUSTY S/SW WINDS WILL BUILD SEAS TO 7-8 FEET MONDAY. SEAS WILL REMAIN ELEVATED INTO TUESDAY MORNING AND CURRENT SCA FOR ALL COASTAL WATERS WILL REMAIN IN EFFECT UNTIL 12Z TUESDAY. HIGH PRESSURE WILL BUILD OVER THE NC WATERS TUESDAY INTO WEDNESDAY WITH WINDS SHIFTING MORE WESTERLY, 5-15 KT. SEAS WILL DIMINISH TO 2-4 FT TUESDAY NIGHT THROUGH WEDNESDAY. A COLD FRONT WILL MOVE SOUTH INTO THE NORTHERN WATERS THURSDAY AND SHIFT SOUTH OF THE WATERS THURSDAY NIGHT. WINDS VEER NORTHWEST BEHIND THE FRONT BUT REMAIN 5-15 KT WITH SEAS 2-4 FEET. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 8 AM EDT TUESDAY FOR AMZ150-152-154-156-158. && $$ SYNOPSIS...JBM NEAR TERM...CTC SHORT TERM...JBM LONG TERM...DAG AVIATION...JBM/DAG MARINE...CTC/JBM/DAG
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
930 AM EDT SUN APR 19 2015 .SYNOPSIS... HIGH PRESSURE EXTENDING OVER THE AREA FROM THE NORTH WILL SHIFT OFFSHORE TODAY. A WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA TONIGHT AS LOW PRESSURE MOVES INTO THE OHIO VALLEY. A COLD FRONT WILL MOVE THROUGH FROM THE WEST EARLY TUESDAY FOLLOWED BY HIGH PRESSURE WEDNESDAY. ANOTHER COLD FRONT WILL MOVE IN FROM THE NORTHWEST THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 925 AM SUNDAY...MADE SOME SLIGHT ADJUSTMENTS TO NEAR-TERM POPS AS LEADING EDGE OF PRECIPITATION SHIELD NOW MOVING INTO NORTHEAST SOUTH CAROLINA AND WILL LIKELY BE A FEW MORE HOURS UNTIL IT ARRIVES IN OUR CWA. THERE ARE A FEW ISOLATED SHOWERS OCCURRING INLAND DUE TO SOME WEAK ISENTROPIC LIFT. GENERALLY FOLLOWED THE 3KM HRRR WHICH IS DOING A GOOD JOB OF DEPICTING THE RAINFALL. NO CHANGES THROUGH THE AFTERNOON AS RAIN BECOMES WIDESPREAD AND STEADY. CONVECTIVE DEVELOPMENT POTENTIAL SEEMS LIMITED BASED ON CURRENT PARAMETERS AS BEST INSTABILITY OCCURRING MUCH FURTHER SOUTHWEST ACROSS GEORGIA...ALABAMA AND THE FLORIDA PANHANDLE. NO CHANGE TO TEMPERATURE FORECAST. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... AS OF 400 AM SUNDAY...LATEST GDNC CONTINUES TO INDICATE WET CONDITIONS TONIGHT AND INCREASED POPS TO 100% ALL ZONES. DIFFLUENT UPR FLOW AHEAD OF UPR TROF LIFTING OUT OF SRN PLAINS WILL INDUCE LARGE SCALE ASCENT ACROSS AREA ALONG WITH DEEP MSTR PLUME FROM GULFMEX. SFC WARM FRONT WILL APPROACH FROM SW AS DEVELOPING LOW PRES MOVES INTO WRN OH VLY. WDSPRD SHOWERS AND PSBLY SCT TSTMS EXPECTED TO GRADUALLY SPREAD SW TO NE ACROSS ERN NC OVERNIGHT. QPF LOWERED SLIGHTLY BASED ON HPC AND LATEST MODEL BLEND...BUT MOST AREAS STILL SEEING 1/2 TO 1 INCH. PER NEAR-TERM...MARGINAL SVR THREAT FOR SW SECTIONS WITH SOME POTENTIAL FOR ROTATING STORMS ALONG AND AHEAD OF WARM FRONT. GENERALLY A HIGH SHEAR/LOW CAPE THREAT WITH WDSPRD CLOUDS AND PCPN LIMITING INSTABILITY. MIN TEMPS MAINLY LOW-MID 60S EVEN WITH WDSPRD RAIN. && .LONG TERM /MONDAY THROUGH SATURDAY/... AS OF 350 AM SUNDAY...BY MONDAY, THE UPPER TROUGH WILL SHIFT EAST NEAR THE GREAT LAKES REGION WITH SEVERAL SHORTWAVES/ VORTICITY MAXIMA ROTATING AROUND THE BASE OF THE UPPER TROUGH. THE SURFACE LOW WILL MOVE NORTHEAST INTO SOUTHEASTERN CANADA WITH THE ATTENDANT COLD FRONT WELL NORTH OF THE REGION. THE BEST LIFT FROM THE NORTHERN STREAM LIFTS WELL NORTH OF THE AREA WHILE THE SOUTHERN STREAM JET REMAINS WELL SOUTHWEST OF EASTERN NC. THE BEST MOISTURE ALSO LIFTS WELL NORTH OF EASTERN NC WITH FORECAST SOUNDINGS INDICATING PWATS FALLING TO 1.20 INCHES MONDAY AFTERNOON. GUIDANCE IS IN GOOD AGREEMENT WITH A SHORTWAVE/VORT MAX MOVING THROUGH EASTERN NC MONDAY AFTERNOON/EVENING WHICH COULD HELP SUPPORT OR ENHANCE ONGOING CONVECTION. 500 MB TEMPS FALL FROM AROUND -11/-12 C SUNDAY TO -15/-16 C MONDAY AFTERNOON INDICATING A FAVORABLE ENVIRONMENT FOR LARGE HAIL SHOULD STORMS BECOME SEVERE. GIVEN SOUTHWESTERLY UNIDIRECTIONAL SHEAR, CAN ALSO EXPECT A FEW SHOWERS/THUNDERSTORMS ALONG THE INLAND MOVING SEA- BREEZE. AS DRY SLOTTING DEVELOPS MONDAY MORNING, CLOUD COVER WILL DIMINISH ALLOWING EXCELLENT INSOLATION. INSTABILITY WILL BE PLENTIFUL THOUGH THE ENVIRONMENT WILL A TRIGGER FOR CONVECTIVE INITIATION, AND LACK VEERING LOW LEVEL WINDS. SPC MAINTAINS A SLIGHT RISK FOR EASTERN NC THROUGH MONDAY EVENING/NIGHT. BIGGEST THREAT WILL BE LARGE HAIL AND DAMAGING WIND GUSTS, THOUGH AN ISOLATED TORNADO CANNOT BE RULED OUT. INCREASED POPS TO CHANCE INLAND MONDAY AFTERNOON. HIGHS MONDAY WILL BE IN THE LOW 80S INLAND AND MID 70S BEACHES. MONDAY NIGHT/TUESDAY...COLD FRONT MOVES OFFSHORE LATE MONDAY NIGHT AND EARLY TUESDAY MORNING WITH SLIGHTLY COOLER AND DRIER AIR MOVING IN. TUESDAY`S HIGHS SHOULD BE IN THE MID 70S...BUT WITH DEWPOINTS DOWN IN THE LOWER 50S BY AFTERNOON. TUESDAY NIGHT/WEDNESDAY...HIGH PRESSURE BUILDS OVERHEAD WITH MAINLY HIGH CLOUDS WEDNESDAY. COOL MORNING LOWS AROUND 50 REBOUND TO AFTERNOON HIGHS IN THE MID 70S. WEDNESDAY NIGHT/THURSDAY...ZONAL FLOW ALOFT CONTINUES AS A COLD FRONT CROSSES THE REGION LATE THURSDAY. GUIDANCE IN MODEST AGREEMENT FOR LIGHT SHOWERS/THUNDERSTORMS THURSDAY, THUS HAVE INTRODUCED SLIGHT CHANCE POP WITH FRONTAL PASSAGE. ANOTHER COOL MORNING THURSDAY WITH LOWS 50 TO 55...REBOUNDING INTO THE UPPER 70S THURSDAY AFTERNOON. THURSDAY NIGHT/FRIDAY...DRY WEATHER BEHIND THE FRONT WITH SUNNY COOLER WEATHER FOR FRIDAY. LOWS AGAIN IN THE 50 TO 55 DEGREE RANGE WITH HIGHS UPPER 60S FAR NORTHEAST AND LOW 70S ELSEWHERE. FRIDAY NIGHT/SATURDAY...ANOTHER SOUTHERN STREAM SYSTEM APPROACHES LATE SATURDAY. HAVE INDICATED INCREASED CLOUD COVER AND A SMALL CHANCE OF RAIN IN THE AFTERNOON. && .AVIATION /13Z SUNDAY THROUGH THURSDAY/... SHORT TERM /THROUGH 12Z MONDAY/... AS OF 700 AM SUNDAY...LIFT STRATUS CIGS DEVELOPED ALL TAF SITES 10-11Z WITH LIFR VSBYS AS WELL AT KPGV AND KISO. CONDITIONS EXPECTED TO LIFT TO VFR BY AROUND 13Z. VFR PERSISTING INTO EARLY AFTN...THEN CONDITIONS DETERIORATING. WIDESPREAD SHOWERS/ISOLD TSTMS EXPECTED TO DEVELOP AND SPREAD SW TO NE ACROSS AREA THIS AFTN INTO EARLY EVENING...WITH WDSPRD IFR CIGS LIKELY ALL TAF SITES BY 00Z AND PERSISTING OVERNIGHT WITH VSBYS 3-5 SM IN SHRA. LIGHT WINDS THIS MORNING WILL BECOME SE 10-15 KT THIS AFTN INTO EVENING. LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 355 AM SUNDAY...PRECIPITATION DIMINISHES MONDAY BUT SOME ISOLATED STRONG TO SEVERE TSTMS MAY BE POSSIBLE, ESPECIALLY KPGV AND KISO, MONDAY AFTERNOON AND EVENING WHICH COULD PRODUCE SUB-VFR AVIATION CONDITIONS. HIGH PRESSURE BUILDS IN ACROSS EASTERN NC TUESDAY INTO WEDNESDAY YIELDING MOSTLY VFR CONDITIONS. A WEAK FRONT WILL MOVE SOUTH INTO EASTERN NC THURSDAY BUT WITH LIMITED MOISTURE SO EXPECT MOSTLY VFR CONDITIONS THURSDAY. && .MARINE... SHORT TERM /THROUGH TONIGHT/... AS OF 930 AM SUNDAY...NO MAJOR CHANGES TO THE CURRENT FORECAST WITH LIGHT NORTHEAST WINDS INTO EARLY AFTERNOON...BECOMING E-SE AS WARM FRONT LIFTS NORTH. WINDS INCREASE TO 15 TO 20 KNOTS BY THIS EVENING. PRES GRAD WILL TIGHTEN TONIGHT WITH WARM FRONT MOVING IN FROM SW...RESULTING IN WINDS BECOMING S-SW 20-25 KT. SEAS BUILDING TO 4-6 FT OUTER WATERS LATE TODAY AND PEAKING 6-8 FT LATE TONIGHT. LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 355 AM SUNDAY...GUSTY S/SW WINDS WILL BUILD SEAS TO 7-8 FEET MONDAY. SEAS WILL REMAIN ELEVATED INTO TUESDAY MORNING AND CURRENT SCA FOR ALL COASTAL WATERS WILL REMAIN IN EFFECT UNTIL 12Z TUESDAY. HIGH PRESSURE WILL BUILD OVER THE NC WATERS TUESDAY INTO WEDNESDAY WITH WINDS SHIFTING MORE WESTERLY, 5-15 KT. SEAS WILL DIMINISH TO 2-4 FT TUESDAY NIGHT THROUGH WEDNESDAY. A COLD FRONT WILL MOVE SOUTH INTO THE NORTHERN WATERS THURSDAY AND SHIFT SOUTH OF THE WATERS THURSDAY NIGHT. WINDS VEER NORTHWEST BEHIND THE FRONT BUT REMAIN 5-15 KT WITH SEAS 2-4 FEET. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 8 AM EDT TUESDAY FOR AMZ150-152-154-156-158. && $$ SYNOPSIS...JBM NEAR TERM...CTC SHORT TERM...JBM LONG TERM...DAG AVIATION...JBM/DAG MARINE...CTC/JBM/DAG
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
121 AM EDT SUN APR 19 2015 .SYNOPSIS... AN APPROACHING FRONTAL SYSTEM WILL BRING SHOWERS AND A CHANCE OF THUNDERSTORMS TODAY THROUGH MONDAY. A FEW STORMS COULD BE STRONG TO SEVERE MONDAY. DRY AND SEASONABLE HIGH PRESSURE WILL BUILD INTO THE AREA TUESDAY AND WEDNESDAY. A WEAK COLD FRONT MAY BRING SHOWERS AND ISOLATED THUNDERSTORMS INTO LATE WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... AS OF 130 AM SUNDAY...WE`RE PROBABLY AT A CONVECTIVE MINIMUM RIGHT NOW. LATEST HRRR AND HRRRX MODELS SHOW AN INCREASE IN SHOWER ACTIVITY LATE TONIGHT...AND ESPECIALLY AROUND DAYBREAK ACROSS THE PEE DEE REGION AS THE DEVELOPING WARM FRONT AND BETTER UPPER SUPPORT ARRIVES FROM THE SOUTHWEST. A FEW DOWNWARD TWEAKS HAVE BEEN MADE TO FORECAST LOW TEMPS NEAR THE COAST. DISCUSSION FROM 1030 PM FOLLOWS... THE DIURNALLY INDUCED CONVECTION CONTINUES TO DISSIPATE ACROSS THE FA AND IS NOW BASICALLY WIDELY SCATTERED IN COVERAGE...AND IN THE FORM OF LIGHT RAIN SHOWERS. WILL DROP POPS TO ISOLATED IN COVERAGE FOR PORTIONS OF THE ILM CWA BUT ONLY FOR TEMPORARILY THIS EVENING UP TO A FEW HRS AFTER MIDNIGHT. WITH A SFC COLD FRONTAL BOUNDARY DROPPING SOUTH AND POSSIBLY BACKDOORING THE FA OVERNIGHT BEFORE TEMPORARILY STALLING...AND A FEW LEFTOVER SHALLOW MESOSCALE SFC BOUNDARIES PRESENT. WILL NOT ENTIRELY REMOVE PCPN FOR THE REMAINDER OF THE OVERNIGHT. IN FACT...DURING THE PRE-DAWN HRS OF SUNDAY THRU DAYBREAK...LOOK FOR POPS TO RAMP BACK UP ACROSS THE ILM CWA FROM SW TO NE...WITH A GOOD CHANCE OR POSSIBLY LIKELY ACROSS THE SW PORTIONS BY SUNRISE SUN. INCREASING MID-LEVEL DYNAMICS FROM A SERIES OF S/W MID-LEVEL TROUGHS...PLENTY OF AVBL MOISTURE WITH 00Z SUNDAY NEARBY SOUNDINGS AND MODEL PROGS INDICATING PWS OF 1.5 TO 1.75 INCHES...AND AS MENTIONED EARLIER...SFC BASED BOUNDARIES WILL LIE ACROSS THE FA ALLOWING FOR SFC BASED CONVERGENCE TO AID MORE ORGANIZED PCPN DEVELOPMENT TO COMPLEMENT THE MID-LEVEL SUPPORT. LATEST MIN TEMPS FORECAST OVERNIGHT LOOKING AOK AND SEE NO REASON TO FURTHER TWEAK FROM EARLIER CHANGES. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...PRIMARY HEADLINES INCLUDE POTENTIAL FOR A GOOD SOAKING OF RAIN...AND A FEW STRONG THUNDERSTORMS. MONDAY APPEARS THE MORE OPTIMUM SET-UP FOR STRONG/SEVERE STORMS WITH MORE ROBUST KINEMATIC FIELDS AND STRONGER LOW-LEVEL HEATING JUST AHEAD OF A COLD FRONT. EXTENSIVE CLOUD CANOPY SUNDAY MAY IMPEDE CONVECTION INITIATION/GROWTH. SUNDAY MEANWHILE OFFERS THE HIGHER RAIN AMOUNTS AS COLUMN MOISTURE SURGES AS A WARM FRONT LIFTS N OF THE AREA AND PRECIPITABLE WATERS SURGE TO 1.8". SEVERAL MCV PERTURBATIONS ALOFT SWEPT NE IN WAKE OF THE WARM FRONT MAY SUSTAIN SHOWER AND STORM CHANCES INTO SUNDAY NIGHT. CURRENT IR ANIMATIONS SHOW COLD TOPS INDEED FLARING ALONG THE NORTHERN GULF OF MEXICO. WPC QPF DEPICTIONS SHOW .75-1 INCH BASIN AVERAGES SUNDAY...AND WITH CONVECTIVE ELEMENTS...SOME AREAS LIKELY TO RECEIVE GREATER AMOUNTS. MONDAY LESS BASIN QPF BUT MORE POWERFUL STORMS IN THE CARDS WITH MAXIMUMS RISING WELL INTO THE 80S AND PARTIAL SUNSHINE AIDING INSOLATION AND CELL POPS. SPC PAINTS SLIGHT RISK FOR BOTH LATE SUNDAY AND MONDAY. BALMY PERIOD OVERALL AND BEST GUESS ON FRONTAL PASSAGE NOW SLATED AROUND OR AFTER DAYBREAK TUESDAY. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 3 PM SATURDAY...AN ALMOST WINTERLIKE LOOKING UPPER PATTERN FOR MOST OF THE PERIOD WITH A LARGE VORTEX IN THE VICINITY OF THE GREAT LAKES. WESTERLY FLOW AROUND THIS FEATURE WILL KEEP MUCH OF THE COLUMN DRY AND LEAD TO RAIN-FREE CONDITIONS LOCALLY. LOW LEVELS WILL BE DRY AS WELL THROUGH SOME TIME WEDNESDAY AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. SOON THEREAFTER THIS HIGH MOVES OFFSHORE AND SOME MOISTENING RETURN FLOW ENSUES. SOME GUIDANCE SHOWING THIS CALLING FOR RAIN AS SOON AS THURSDAY BUT GIVEN THE AFOREMENTIONED DOWNSLOPE FLOW STILL FEEL THAT THURSDAY NIGHT INTO FRIDAY IS THE BETTER DAY TO INTRODUCE SOME RAIN CHANCES ESPECIALLY GIVEN THE APPROACH OF A COLD FRONT. THOUGH THIS SURFACE BOUNDARY MAY LIE TO OUR SOUTH ON SATURDAY SOME LOW LEVEL BAROCLINICITY PAIRED WITH MID LEVEL VORT APPROACHING TO KEEP RAIN IN THE FORECAST. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... AS OF 06Z...A MIXTURE OF VFR/MVFR THROUGH THE EARLY OVERNIGHT HOURS DUE TO LOW CIGS AND PATCHY FOG...WITH CONDITIONS DETERIORATING TO MVFR/IFR LATE OVERNIGHT AND THROUGH INTO SUNDAY WITH AN APPROACHING FRONTAL SYSTEM. OVERALL...VFR PREVAILS ACROSS THE AREA TONIGHT WITH LIGHT AND VARIABLE WINDS AND INTERMITTENT LOW CIGS...AS WELL AS MID TO HIGH CLOUDS AS SEEN FROM LATEST SATELLITE IMAGERY. OBSERVATIONS ARE ALSO DEPICTING PATCHY FOG INLAND...JUST AT MARGINAL VFR/MVFR STATUS ATTM. WITH ISOLATED LIGHT SHOWERS SLOWLY MOVING ACROSS THE AREA...ANTICIPATE CONDITIONS TO DETERIORATE OVERNIGHT CREATING WIDESPREAD MVFR/IFR DUE TO LOW CIGS AND AREAS OF FOG. AFTER DAYBREAK...EXPECT EASTERLY WINDS AOB 12 KTS IN THE MORNING TO BECOME EAST-SOUTHEAST BY AFTERNOON WITH GUSTS UP NEAR 20 KTS POSSIBLE WITH A FRONTAL SYSTEM TO AFFECT THE AREA. A MIXTURE OF VFR/MVFR/IFR IS ANTICIPATED AS SHOWERS AND ISOLATED THUNDERSTORMS...ALONG WITH LOW CIGS AND PATCHY AREAS OF FOG MOVE THROUGHOUT THE AREA THROUGH THE END OF THE VALID TAF PERIOD. EXTENDED OUTLOOK...MVFR/IFR POSSIBLE INTO MONDAY WITH SHOWERS AND ISOLATED THUNDERSTORMS. A COLD FRONT WILL PUSH THROUGH THE AREA MONDAY NIGHT WITH SHOWERS POSSIBLE FOLLOWED BY MAINLY VFR CONDITIONS TUESDAY. POSSIBLE SHOWERS RETURNING LATER IN THE WEEK. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 130 AM SUNDAY...BASED ON OBSERVATIONS ALONG THE COAST I HAVE BACKED WIND DIRECTIONS MORE NORTHERLY. NO OTHER SIGNIFICANT CHANGES ARE NEEDED. DISCUSSION FROM 1030 PM FOLLOWS... NO CHANGES TO THE WINDS FROM THE PREVIOUS UPDATE. WINDS TO BECOME NE- E THROUGHOUT...AND INCREASE TO 10-15 KT...WITH THE HIGHER WIND SPEEDS FROM CAPE FEAR NORTHWARD. THIS A RESULT OF THE BACKDOOR FRONTS POSITIONING WITH ENOUGH TIGHTENING OF THE SFC PG AS RIDGING EXTENDS SOUTH FROM THE NE STATES SFC HIGH. SIGNIFICANT SEAS WILL RUN 2 TO 4 FT...WITH THE 4 FOOTERS PRIMARILY ACROSS THE OUTER WATERS OFF CAPE FEAR...AND NORTHWARD. DOMINANT PERIODS WILL RUN 8 TO 9 SECONDS IN RESPONSE TO THE 2 TO 3 FOOT ESE GROUND SWELL. HAVE REDUCED THE POPS FOR THIS EVENING BASED ON LATEST 88D TRENDS. SHOULD SEE POPS INCREASE DURING THE PRE-DAWN SUN HRS. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...EXERCISE CAUTION OR ADVISORY MARINE REGIME ON TAP THIS PERIOD AS A FRONTAL SYSTEM APPROACHES AND WORSENS LOCAL MARINE CONDITIONS. WAVE GROWTH HOWEVER MAY BE LIMITED SINCE SE-S WIND FLOW HAS LIMITED STAYING TIME BEFORE WINDS GO SW EARLY ON MONDAY. HAVE CAPPED SEAS AT 5 FEET SUNDAY FOR NOW WITH GUSTS TO 20 KT AHEAD OF THE COLD FRONT...SET TO CROSS THE WATERS TUESDAY MORNING. SEVERAL STRONG TSTMS ARE POSSIBLE SUNDAY THROUGH THROUGH EARLY TUESDAY AND SPECIAL MARINE WARNINGS MAY BE NEEDED AT TIMES. LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 3 PM SATURDAY...OFFSHORE/NORTHWESTERLY POST COLD FRONTAL FLOW REGIME ON TUESDAY WILL GROW LIGHTER LATE IN THE DAY AND AT NIGHT AS CENTER OF HIGH PRESSURE APPROACHES. THE CENTER OF HIGH PRESSURE MOVES OFFSHORE BY WEDNESDAY EVENING. THIS WILL BRING A PERIOD OF VERY LIGHT GRADIENT WHEREIN WINDS REMAIN UNDER 10 KNOTS AND VEER IN DIRECTION FOR AN EXTENDED TIME UNTIL FINALLY SETTLING ON SOUTHERLY BY WED EVE. SUCH LIGHT WINDS IN THE ABSENCE OF SWELL ENERGY OUGHT TO BE GOOD FOR MINIMAL SEAS OF 2 FT OR LESS. THE HIGH MOVES FURTHER OFFSHORE ON THURSDAY ALLOWING FOR A ONE CATEGORY RISE IN WINDS AND A WAVES FORECAST RISING TO JUST THE 2 TO 3 FT RANGE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...MJC NEAR TERM...DCH/TRA SHORT TERM...MJC LONG TERM...MBB AVIATION...SGL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1203 PM CDT SUN APR 19 2015 .UPDATE... ISSUED AT 1202 PM CDT SUN APR 19 2015 QUICK UPDATE TO ADD A MENTION OF ISOLATED THUNDERSTORMS THIS AFTERNOON WITH SMALL HAIL BEING REPORTED ACROSS MUCH OF WESTERN AND CENTRAL NORTH DAKOTA WITH SHALLOW CONVECTION ASSOCIATED WITH COOL TEMPERATURES ALOFT. UPDATE ISSUED AT 929 AM CDT SUN APR 19 2015 THE FORECAST FOR THE REMAINDER OF TODAY IS ON TRACK WITH THE STRATUS FIELD OVERTAKING WESTERN AND CENTRAL NORTH DAKOTA EXPECTED TO SLOWLY SCATTER WITH DIURNAL HEATING WITH RAIN SHOWER COVERAGE INCREASING THROUGH THE AFTERNOON. THIS IS IN LINE WITH THE 12-13 UTC HRRR ITERATIONS. UPDATE ISSUED AT 629 AM CDT SUN APR 19 2015 INITIAL BATCH OF WIDESPREAD RAIN CONTINUES TO PUSH OFF TO THE EAST...THOUGH SECONDARY ROUND OF SCATTERED WRAP AROUND SHOWERS ARE STARTING TO DEVELOP AND WORK INTO FAR NORTHWEST NORTH DAKOTA. HAVE ADJUSTED POPS TO ACCOUNT FOR THIS. HAVE ALSO INCREASED CLOUD COVER MAINLY OVER THE WEST AS CLOUDS CONTINUE TO STREAM IN BEHIND THE LOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 400 AM CDT SUN APR 19 2015 CONTINUED CHANCES FOR RAIN AND WINDY CONDITIONS THROUGH SUNDAY...HIGHLIGHT THE SHORT TERM. AN UPPER LEVEL TROUGH OVER THE NORTHERN PLAINS WILL CONTINUE TO PROVIDE AMPLE MOISTURE AND INSTABILITY...PROLONGING CHANCES FOR WIDESPREAD SHOWERS IN CENTRAL AND EASTERN AREAS OF THE STATE THROUGH THE DAY. ADDITIONALLY...TEMPERATURES SLIGHTLY BELOW AVERAGE AND STRONG NORTHWEST WINDS WILL ACCOMPANY THE DEEPENING TROUGH. THE CURRENT 00Z MODEL SUITE PROVIDES GOOD AGREEMENT ON THE UPPER LEVEL TROUGH DIGGING AND SLOWLY MOVING EASTWARD...PUSHING OVER MINNESOTA/EASTERN MANITOBA AND CLOSING OFF BY 12Z MONDAY. NORTH CENTRAL NORTH DAKOTA INTO THE JAMES RIVER VALLEY HAVE THE POTENTIAL FOR A FEW SNOW FLAKES EARLY MONDAY MORNING...AS COLD AIR FILTERING SOUTHWARD FROM CANADA IS EXPECTED TO DROP OVERNIGHT LOWS TO JUST BELOW FREEZING. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 400 AM CDT SUN APR 19 2015 UPPER LOW WILL WORK ALONG THE MINNESOTA/ONTARIO BORDER ON MONDAY. THIS SHOULD KEEP PRECIPITATION TO THE EAST OF OUR AREA THROUGH THE DAY...THOUGH GUSTY NORTHWEST WINDS WILL CONTINUE IN THE WAKE OF THE SYSTEM. A FAST MOVING WAVE WILL MOVE IN BEHIND THE SYSTEM LATE TUESDAY NIGHT INTO EARLY WEDNESDAY WHICH MAY BRING A LITTLE LIGHT PRECIPITATION TO CENTRAL NORTH DAKOTA...BUT WILL KEEP POPS LOW WITH LACK OF MUCH MOISTURE TO WORK WITH. QUIET AND COOL CONDITIONS ARE THEN EXPECTED WITH RIDGING TO THE WEST AND NORTHWESTERLY FLOW OVER OUR AREA. MODELS START TO DISAGREE WITH THE POSITION OF THE RIDGE AND WHETHER A FEW UPPER WAVES WILL MAKE IT THROUGH THE AREA TOWARDS THE END OF THE WEEK. THEREFORE...WILL KEEP ANY PRECIPITATION CHANCES ON THE LOW SIDE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1202 PM CDT SUN APR 19 2015 MVFR/VFR STRATUS THIS MORNING IS EXPECTED TO SLOWLY LIFT AND SCATTER INTO THE AFTERNOON WITH RAIN SHOWER COVERAGE ALSO INCREASING INTO THE AFTERNOON. ISOLATED THUNDERSTORMS WITH SMALL HAIL ARE POSSIBLE. STRONG NORTHWEST WIND GUSTS OF 30-35 KTS ARE ALSO FORECAST ACROSS WESTERN AND CENTRAL NORTH DAKOTA TODAY. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...AC LONG TERM...JJS AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
929 AM CDT SUN APR 19 2015 .UPDATE... ISSUED AT 929 AM CDT SUN APR 19 2015 THE FORECAST FOR THE REMAINDER OF TODAY IS ON TRACK WITH THE STRATUS FIELD OVERTAKING WESTERN AND CENTRAL NORTH DAKOTA EXPECTED TO SLOWLY SCATTER WITH DIURNAL HEATING WITH RAIN SHOWER COVERAGE INCREASING THROUGH THE AFTERNOON. THIS IS IN LINE WITH THE 12-13 UTC HRRR ITERATIONS. UPDATE ISSUED AT 629 AM CDT SUN APR 19 2015 INITIAL BATCH OF WIDESPREAD RAIN CONTINUES TO PUSH OFF TO THE EAST...THOUGH SECONDARY ROUND OF SCATTERED WRAP AROUND SHOWERS ARE STARTING TO DEVELOP AND WORK INTO FAR NORTHWEST NORTH DAKOTA. HAVE ADJUSTED POPS TO ACCOUNT FOR THIS. HAVE ALSO INCREASED CLOUD COVER MAINLY OVER THE WEST AS CLOUDS CONTINUE TO STREAM IN BEHIND THE LOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 400 AM CDT SUN APR 19 2015 CONTINUED CHANCES FOR RAIN AND WINDY CONDITIONS THROUGH SUNDAY...HIGHLIGHT THE SHORT TERM. AN UPPER LEVEL TROUGH OVER THE NORTHERN PLAINS WILL CONTINUE TO PROVIDE AMPLE MOISTURE AND INSTABILITY...PROLONGING CHANCES FOR WIDESPREAD SHOWERS IN CENTRAL AND EASTERN AREAS OF THE STATE THROUGH THE DAY. ADDITIONALLY...TEMPERATURES SLIGHTLY BELOW AVERAGE AND STRONG NORTHWEST WINDS WILL ACCOMPANY THE DEEPENING TROUGH. THE CURRENT 00Z MODEL SUITE PROVIDES GOOD AGREEMENT ON THE UPPER LEVEL TROUGH DIGGING AND SLOWLY MOVING EASTWARD...PUSHING OVER MINNESOTA/EASTERN MANITOBA AND CLOSING OFF BY 12Z MONDAY. NORTH CENTRAL NORTH DAKOTA INTO THE JAMES RIVER VALLEY HAVE THE POTENTIAL FOR A FEW SNOW FLAKES EARLY MONDAY MORNING...AS COLD AIR FILTERING SOUTHWARD FROM CANADA IS EXPECTED TO DROP OVERNIGHT LOWS TO JUST BELOW FREEZING. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 400 AM CDT SUN APR 19 2015 UPPER LOW WILL WORK ALONG THE MINNESOTA/ONTARIO BORDER ON MONDAY. THIS SHOULD KEEP PRECIPITATION TO THE EAST OF OUR AREA THROUGH THE DAY...THOUGH GUSTY NORTHWEST WINDS WILL CONTINUE IN THE WAKE OF THE SYSTEM. A FAST MOVING WAVE WILL MOVE IN BEHIND THE SYSTEM LATE TUESDAY NIGHT INTO EARLY WEDNESDAY WHICH MAY BRING A LITTLE LIGHT PRECIPITATION TO CENTRAL NORTH DAKOTA...BUT WILL KEEP POPS LOW WITH LACK OF MUCH MOISTURE TO WORK WITH. QUIET AND COOL CONDITIONS ARE THEN EXPECTED WITH RIDGING TO THE WEST AND NORTHWESTERLY FLOW OVER OUR AREA. MODELS START TO DISAGREE WITH THE POSITION OF THE RIDGE AND WHETHER A FEW UPPER WAVES WILL MAKE IT THROUGH THE AREA TOWARDS THE END OF THE WEEK. THEREFORE...WILL KEEP ANY PRECIPITATION CHANCES ON THE LOW SIDE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 925 AM CDT SUN APR 19 2015 MVFR/VFR STRATUS WILL CONTINUE TO SPREAD ACROSS WESTERN AND CENTRAL NORTH DAKOTA THIS MORNING. THIS DECK IS EXPECTED TO SLOWLY LIFT AND SCATTER INTO THE AFTERNOON WITH RAIN SHOWER COVERAGE ALSO INCREASING INTO THE AFTERNOON. STRONG NORTHWEST WIND GUSTS OF 30-35 KTS ARE ALSO FORECAST ACROSS WESTERN AND CENTRAL NORTH DAKOTA TODAY. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...AC LONG TERM...JJS AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1218 AM CDT SUN APR 19 2015 .UPDATE... ISSUED AT 1218 AM CDT SUN APR 19 2015 NO CHANGES MADE TO THE PREVIOUS FORECAST. UPDATE ISSUED AT 955 PM CDT SAT APR 18 2015 ALTHOUGH THE 01 UTC RAP/HRRR ARE OVERDOING THE QPF IN MOST AREAS...THEY HAVE A GOOD HANDLE ON THE AREA OF PRECIPITATION AND HAVE UTILIZED THIS BLEND FOR POPS THROUGH THE NIGHT AND INTO SUNDAY. BEST PRECIPITATION CHANCES WILL REMAIN OVER THE SOUTHEAST FORECAST AREA. EXPECT PRECIPITATION TO FILL IN OVER THE JAMES RIVER VALLEY OVER THE NEXT FEW HOURS. PRECIPITATION BAND FROM SOUTHWEST INTO NORTH CENTRAL NORTH DAKOTA WILL MOVE ACROSS CENTRAL NORTH DAKOTA AS WELL...WITH BEST PRECIPITATION CHANCES OVER BISMARCK THROUGH AROUND MIDNIGHT. PRECIPITATION IS EXPECTED TO MOVE OUT OF THE JAMES RIVER VALLEY AROUND 12-14Z...LOWERED POPS ACROSS THE AREA EARLY MORNING...THEN BUMPED THEM UP MID TO LATE MORNING INTO THE AFTERNOON AS WRAP AROUND MOISTURE MOVES INTO THE AREA ON THE BACK SIDE OF THE EXITING SYSTEM. UPDATE ISSUED AT |748 PM CDT SAT APR 18 2015 QUICK UPDATE FOR POPS BASED ON LATEST RADAR...ALSO REMOVED THUNDER OVER THE SOUTHWEST. HEAVIEST SHOWERS LOOK TO REMAIN OVER THE FAR SOUTH CENTRAL AND INTO EASTERN NORTH DAKOTA THIS EVENING. BAND MOVING EAST ACROSS THE CENTRAL FROM AROUND MINOT TO GARRISON TO HEBRON SHOULD HELP MOISTEN THE ATMOSPHERE NEAR KBIS THIS EVENING. SHOWERS IN THE FAR SOUTH CENTRAL MOVING TOWARD BISMARCK ARE NOW DISSIPATING ON THE NORTHERN FRINGE. 19 APRIL 00 UTC SOUNDING STILL SHOWS QUITE A BIT OF DRY AIR BELOW THE MID AND UPPER LEVEL MOISTURE BEGINNING AROUND 10K FEET. UPDATE ISSUED AT 638 PM CDT SAT APR 18 2015 UPPER LEVEL LOW OVER SOUTHEAST COLORADO WITH A SHORTWAVE TROUGH LIFTING NORTH THROUGH WESTERN SOUTH DAKOTA IS PUSHING SHOWERS INTO CENTRAL NORTH DAKOTA. A NORTHERN STREAM WAVE WITH MORE INSOLATION TO WORK WITH IS PRODUCING A LINE OF POST FRONTAL SHOWERS AND ISOLATED THUNDER OVER WESTERN AND NORTH CENTRAL NORTH DAKOTA. THE THUNDER IS LIMITED TO THE SOUTHWEST...AND WITH THE LOSS OF DAYTIME HEATING...DO NOT EXPECT THUNDER TO CONTINUE MUCH LONGER. WILL KEEP A MENTION THROUGH THE EARLY EVENING. EXPECT SHOWERS TO INCREASE OVER SOUTH CENTRAL INTO EASTERN NORTH DAKOTA LATER THIS EVENING AS THE SHORTWAVES LIFTING NORTH AND TRACKING EAST CONVERGE OVER CENTRAL NORTH DAKOTA...AND THEN MOVE INTO BETTER MOISTURE AND SURFACE SUPPORT AS THE SYSTEM MOVES INTO EASTERN NORTH DAKOTA LATE TONIGHT. ADJUSTED POPS/SKY COVER BASED MAINLY ON SHORT TERM CONSENSUS MODEL AND LATEST RADAR. OTHERWISE NO SIGNIFICANT CHANGES FROM THE GOING FORECAST. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 315 PM CDT SAT APR 18 2015 RAINFALL POTENTIAL THROUGH TONIGHT HIGHLIGHTS THE SHORT TERM FORECAST. AS OF 1930 UTC...A COLD FRONT WAS JUST ENTERING NORTHWEST NORTH DAKOTA AND WILL CONTINUE TO PROPAGATE THROUGH CENTRAL NORTH DAKOTA THIS EVENING. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WITH WEAK INSTABILITY HAVE DEVELOPED ALONG THIS FRONT AND WILL APPROACH THE HIGHWAY 83 CORRIDOR BY 01-02 UTC. AS CYCLOGENESIS OCCURS ACROSS EASTERN SOUTH DAKOTA THROUGH THE NIGHT AND THE NORTHERN STREAM WAVE ASSOCIATED WITH THE COLD FRONT PHASES WITH THE LOW TO THE SOUTH...RAINFALL COVERAGE WILL INCREASE ACROSS CENTRAL NORTH DAKOTA THROUGH THE EVENING AND NIGHT. THEREAFTER...A WINDY SUNDAY IS FORECAST IN THE WAKE OF THE NOW DEEPENING LOW ACROSS MINNESOTA. AT THIS TIME...WIND GUSTS APPEAR TO STAY BELOW ADVISORY CRITERIA WITH 30 TO 35 KTS TO MIX IN COLD AIR ADVECTION. SCATTERED LIGHT RAIN SHOWERS ARE ALSO EXPECTED IN WRAP AROUND MOISTURE WITH PERHAPS A FEW SNOWFLAKES MIXING IN SUNDAY MORNING AS TEMPERATURES FALL INTO THE MID 30S NORTHWEST AND NORTH CENTRAL. GIVEN GOOD AGREEMENT...WILL WEIGH HEAVILY ON THE 16-18 UTC HRRR ITERATIONS BLENDED TO THE GLOBAL 12 UTC DETERMINISTIC AND ENSEMBLE SUITE. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 315 PM CDT SAT APR 18 2015 WINDY WITH SCATTERED SHOWERS TO BEGIN THE EXTENDED...COOL AND DRY THROUGH THE REMAINDER OF THE WEEK. AS THE MAIN SURFACE LOW ENTERS NORTHERN MINNESOTA AND SOUTHERN CANADA...MOISTURE SHOULD WRAP AROUND THE BACKSIDE...PROVIDING NORTH DAKOTA WITH SOME SCATTERED LIGHT RAIN. THE HIGH RESOLUTION SHORT TERM MODELS ARE A LITTLE MORE ROBUST WITH PRECIPITATION COVERAGE THAN THE GLOBAL MODELS (ECMWF/GFS). WITH THE LOW REMAINING NEARBY AND REMAINING UNDER THE INFLUENCE OF A FAVORABLE JET STREAK...LIGHT SHOWERS HERE AND THERE AREN`T OUT OF THE QUESTION THROUGH TUESDAY. GUSTY WINDS ARE EXPECTED THOUGH THE DAY SUNDAY AND MONDAY AS THE PRESSURE GRADIENT TIGHTENS WITH THE SURFACE LOW DEEPENING AND PROPAGATING TOWARD THE GREAT LAKES. THESE GUSTY NORTHWEST WINDS WILL BE ADVECTING DRIER AIR INTO THE AREA. THIS COULD CREATE RATHER CRITICAL FIRE CONDITIONS MONDAY AS RELATIVE HUMIDITY DROPS BELOW 20 PERCENT. THROUGH THE REMAINDER OF THE WORK WEEK...UPPER LOW SLOWLY WORKS OFF TO THE EAST KEEPING NORTH/NORTHWESTERLY FLOW OVER OUR AREA. WITH THE EXCEPTION OF ISOLATED SHOWERS EARLY THIS WEEK...DRY WEATHER IS EXPECTED. TEMPERATURES WILL REMAIN A BIT BELOW AVERAGE WITH READINGS IN THE 50S FOR HIGHS AND 20S/30S FOR LOWS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1218 AM CDT SUN APR 19 2015 WIDESPREAD RAIN IS EXPECTED TO CONTINUE THROUGH 06Z MONDAY. KBIS/KJMS HAVE THE GREATEST CHANCES FOR RAIN WITH PERIODS OF MVFR CONDITIONS POSSIBLE AT EACH OF THE TAF SITES. && .FIRE WEATHER... ISSUED AT 315 PM CDT SAT APR 18 2015 CRITICAL FIRE WEATHER CONDITIONS MAY BE POSSIBLE ON MONDAY...AND THIS WILL NEED TO BE MONITORED. WHILE TEMPERATURES WILL ONLY BE IN THE 50S...MINIMUM RELATIVE HUMIDITY LEVELS OF 15 TO 20 PERCENT AND NORTHWEST WINDS OF 25 TO 35 MPH ARE POSSIBLE. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AC SHORT TERM...AYD LONG TERM...AJ AVIATION...AC FIRE WEATHER...AYD
AREA FORECAST DISCUSSION
NWS TULSA OK
1101 PM CDT MON APR 20 2015 .DISCUSSION... THE 06Z TAF DISCUSSION IS INCLUDED BELOW. && .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. NO MAJOR CHANGES TO THE 00Z FORECAST. VFR CONDITIONS WILL PREVAIL WITH INCREASING MID CLOUD CIGS TOWARD 12Z TUES MORNING. INCREASING WARM ADVECTION ABOVE THE SURFACE WILL YIELD SOME SCT SHRA AND POSSIBLY A FEW TSRA TUES MORNING. LACY && .PREV DISCUSSION... /ISSUED 732 PM CDT MON APR 20 2015/ DISCUSSION... HAVE EXPANDED THE SLIGHT CHANCE POPS FOR TONIGHT AS THE LAST FEW RUNS OF THE HRRR HAVE BEEN CONSISTENT IN SPREADING THE PRECIP ACROSS A WIDER SWATH OF EASTERN OKLAHOMA THROUGH 12Z. OTHERWISE...CURRENT FORECAST FOR TONIGHT IS ON TRACK. PREV DISCUSSION... /ISSUED 610 PM CDT MON APR 20 2015/ DISCUSSION... THE 00Z TAF DISCUSSION IS INCLUDED BELOW. AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. VFR CONDITIONS WILL PREVAIL. INCREASING WARM ADVECTION ABOVE THE SURFACE WILL PRODUCE MID CLOUD AND CHANCES FOR SHOWERS...POSSIBLY A FEW STORMS...BY TUESDAY MORNING. CIGS WILL REMAIN IN THE VFR RANGE HOWEVER. LACY PREV DISCUSSION... /ISSUED 351 PM CDT MON APR 20 2015/ DISCUSSION... CLOUDINESS WILL BE ON THE INCREASE TONIGHT AS A WEAK UPPER LEVEL IMPULSE APPROACHES THE AREA. SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL MOVE INTO THE AREA LATE TONIGHT AND CONTINUE INTO TUESDAY IN ASSOCIATION WITH THIS SYSTEM. A FRONTAL BOUNDARY WILL MOVE SOUTH INTO THE AREA LATE TUESDAY NIGHT AND WEDNESDAY AND WILL STALL NEAR THE RED RIVER. THIS BOUNDARY WILL THEN RETURN NORTH LATE IN THE WEEK AND WILL BE THE FOCUS FOR SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS. THERE WILL BE SOME SEVERE WEATHER THREAT WEDNESDAY AND THURSDAY...ESPECIALLY IF EARLY DAY CONVECTION IS NOT TOO EXTENSIVE...ALTHOUGH THE GREATER THREAT MAY BE TO OUR SOUTHWEST WHERE INSTABILITY WILL BE MAXIMIZED. FRIDAY LOOKS TO BE THE DAY OF GREATEST CONCERN IN OUR AREA AS LOW PRESSURE ALOFT LIFTS NORTHEAST FROM NEW MEXICO INTO KANSAS AND A DRYLINE BEGINS TO SURGE EAST ACROSS OKLAHOMA. A FEW SHOWERS MAY LINGER INTO SATURDAY BUT MOST OF THE WEEKEND WILL BE DRY BEFORE LOW RAIN CHANCES RETURN BY THE EARLY PART OF NEXT WEEK. STAYED CLOSE TO GUIDANCE TEMPERATURES THE NEXT COUPLE DAYS. && .PRELIMINARY POINT TEMPS/POPS... TUL 48 73 52 70 / 10 40 20 50 FSM 45 72 52 73 / 10 30 10 50 MLC 47 71 54 74 / 20 30 20 50 BVO 44 74 50 68 / 10 30 20 40 FYV 40 68 47 68 / 0 40 10 40 BYV 43 67 49 66 / 0 30 10 40 MKO 46 72 52 72 / 20 30 10 50 MIO 42 70 49 66 / 0 40 30 30 F10 45 72 54 72 / 20 30 20 50 HHW 46 72 55 75 / 10 20 20 70 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...30
AREA FORECAST DISCUSSION
NWS TULSA OK
732 PM CDT MON APR 20 2015 .DISCUSSION... HAVE EXPANDED THE SLIGHT CHANCE POPS FOR TONIGHT AS THE LAST FEW RUNS OF THE HRRR HAVE BEEN CONSISTENT IN SPREADING THE PRECIP ACROSS A WIDER SWATH OF EASTERN OKLAHOMA THROUGH 12Z. OTHERWISE...CURRENT FORECAST FOR TONIGHT IS ON TRACK. && .PREV DISCUSSION... /ISSUED 610 PM CDT MON APR 20 2015/ DISCUSSION... THE 00Z TAF DISCUSSION IS INCLUDED BELOW. AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. VFR CONDITIONS WILL PREVAIL. INCREASING WARM ADVECTION ABOVE THE SURFACE WILL PRODUCE MID CLOUD AND CHANCES FOR SHOWERS...POSSIBLY A FEW STORMS...BY TUESDAY MORNING. CIGS WILL REMAIN IN THE VFR RANGE HOWEVER. LACY PREV DISCUSSION... /ISSUED 351 PM CDT MON APR 20 2015/ DISCUSSION... CLOUDINESS WILL BE ON THE INCREASE TONIGHT AS A WEAK UPPER LEVEL IMPULSE APPROACHES THE AREA. SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL MOVE INTO THE AREA LATE TONIGHT AND CONTINUE INTO TUESDAY IN ASSOCIATION WITH THIS SYSTEM. A FRONTAL BOUNDARY WILL MOVE SOUTH INTO THE AREA LATE TUESDAY NIGHT AND WEDNESDAY AND WILL STALL NEAR THE RED RIVER. THIS BOUNDARY WILL THEN RETURN NORTH LATE IN THE WEEK AND WILL BE THE FOCUS FOR SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS. THERE WILL BE SOME SEVERE WEATHER THREAT WEDNESDAY AND THURSDAY...ESPECIALLY IF EARLY DAY CONVECTION IS NOT TOO EXTENSIVE...ALTHOUGH THE GREATER THREAT MAY BE TO OUR SOUTHWEST WHERE INSTABILITY WILL BE MAXIMIZED. FRIDAY LOOKS TO BE THE DAY OF GREATEST CONCERN IN OUR AREA AS LOW PRESSURE ALOFT LIFTS NORTHEAST FROM NEW MEXICO INTO KANSAS AND A DRYLINE BEGINS TO SURGE EAST ACROSS OKLAHOMA. A FEW SHOWERS MAY LINGER INTO SATURDAY BUT MOST OF THE WEEKEND WILL BE DRY BEFORE LOW RAIN CHANCES RETURN BY THE EARLY PART OF NEXT WEEK. STAYED CLOSE TO GUIDANCE TEMPERATURES THE NEXT COUPLE DAYS. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...10
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1148 PM EDT MON APR 20 2015 .SYNOPSIS... A COLD FRONT WILL MOVE THROUGH LATER TONIGHT AND BRING AN END TO THE STEADY SHOWERS AND THUNDERSTORMS. A LARGE UPPER LEVEL LOW WILL SET UP OVER ONTARIO AND QUEBEC FOR THE MIDDLE AND LATTER PART OF THE WEEK...USHERING IN UNSEASONABLY COOL AIR WHICH WILL LAST INTO THE WEEKEND OR LONGER. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 10 PM UPDATE...HAVE ALLOWED THE TORNADO WATCH TO EXPIRE. CONVECTION IS STILL ACTIVE OVER THE EASTERN ZONES...BUT TOPS HAVE COME DOWN WITH THE LOSS OF DAYLIGHT AND THE MAIN THREAT NOW WILL BE SMALL HAIL AND BRIEF DOWNPOURS. DID BUMP UP POPS INTO THE WEE HOURS ACCORDING TO THE LATEST RADAR TRENDS AND HRRR WHICH SHOW MORE SHOWERS GATHERING TO OUR SOUTHWEST...SLATED TO MOVE THROUGH OVER THE NEXT 3-6 HOURS. SFC COLD FRONT NOW CROSSING THE PA/OHIO BORDER AND WILL PUSH EAST ACROSS THE ENTIRE CWA BY 06Z. THE COOLER MOIST UPSLOPE FLOW BEHIND THE FRONT WILL CREATE PLENTY OF LOW STRATUS ACROSS THE WRN ALLEGHENIES...WHILE MOST OF THE CENTRAL VALLEY REGION WILL FLUCTUATE BETWEEN SCT AND BKN CONDITIONS FOR THE REST OF THE OVERNIGHT. MIN TEMPS WILL RANGE FROM THE LOWER 40S ACROSS THE LAURELS AND NW MTNS...TO THE LOWER 50S IN THE SE. WESTERLY WIND WILL INCREASE AND GUST TO THE MID AND UPPER 20KT RANGE LATE TONIGHT...SIMILAR TO WHAT WE/RE CURRENTLY SEEING ACROSS CENTRAL AND ERN OHIO. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... COLD ADVECTION AND WESTERLY UPSLOPE FLOW WILL LEAD TO SCT SHRA OVER THE NW INTO THE DAY ON TUESDAY...WITH VARIABLE AMOUNTS OF CLOUDS AND SPRINKLES W/ISOLATED SHRA ALONG AND JUST TO THE SE OF THE I-99/RT 220 CORRIDOR. MOSTLY SUNNY SKIES EXPECTED FOR THE FAR SE ZONES. MAXES TUESDAY WILL BE AROUND 50F IN THE NW AND PERHAPS THE LAURELS AS WELL. THE LOWER SUSQ WILL PROBABLY REACH THE LOWER 60S. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... THE LONG TERM PATTERN WILL BE DOMINATED BY A LARGE UPPER LEVEL LOW MOVING THROUGH THE NORTHERN GREAT LAKES...AND THROUGH SOUTHERN CANADA MIDWEEK TO THE WEEKEND. THERE IS GOOD MODEL CONSENSUS THROUGH THE MID RANGE PERIOD. AFTER THE FRONT LIFTS OUT BY TUESDAY MORNING THE UPPER LOW HANGS AROUND S CANADA/NEW ENGLAND FOR SEVERAL DAYS KEEPING FAIRLY BRISK W/NW FLOW ACROSS PA. THIS WILL BRING A STEADY STREAM OF COLDER AIR AS TEMPS SLOWLY SLIP A BIT LOWER EACH DAY WITH BELOW NORMAL READINGS FOR A SEVERAL DAY PERIOD LINGERING INTO NEXT WEEKEND. PROXIMITY OF UPPER LOW WILL ALSO KEEP MENTION OF SCT SHOWERS IN THE FORECAST. A SHORTWAVE SHOULD DROP THROUGH THE REGION WEDNESDAY AFTERNOON INTO THURSDAY MORNING. THIS COULD DROP EVEN COLDER AIR INTO THE REGION BRINGING THE POSSIBILITY OF SNOW TO THE NW TO THE CENTRAL REGIONS OF PA. THE MODELS ARE BECOMING CLOSER TO A CONSENSUS SOLUTION...HOWEVER SOLUTION IS TRENDING TOWARD THE UPPER LEVEL LOW TO BECOME QUASI-STATIONARY AND SLOWLY SPINNING OVER QUEBEC.WITH ONLY A SLIGHT CHANCE FOR PRECIPITATION NEXT WEEKEND. THE MOVEMENT OF THE LOW WILL DOMINATE THE PATTERN NEXT WEEK WITH IT POSSIBLY RETROGRADING AND SWINGING ANOTHER TROUGH THROUGH THE REGION NEXT WEEK. && .AVIATION /04Z TUESDAY THROUGH SATURDAY/... ASIDE FROM BRIEF IFR VIS IN +TSRA INVOF MDT/LNS THRU 06Z...EXPECT MVFR/VFR CONDITIONS TO PREVAIL OVERNIGHT AND INTO TUESDAY. SFC WNDS FROM 250 TO 300 DEGREES WILL BECOME GUSTY AT 25-30KTS BY TUESDAY MORNING WITH PREDOMINATELY SCT TO BKN MVFR TO VFR CIGS. OUTLOOK... WED-SAT...PERSISTENT NW FLOW PATTERN WILL FAVOR MVFR CIGS OVER THE NW AIRSPACE IN ZOB SECTOR...WITH MAINLY VFR CONDITIONS PREVAILING IN ZNY DOMAIN. ISOLD TO SCT SHOWERS WILL BE POSSIBLE ACROSS ALL OF THE AIRSPACE THROUGH THE REMAINDER OF THE WEEK. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/LAMBERT NEAR TERM...LA CORTE/LAMBERT SHORT TERM...LAMBERT/CERU LONG TERM...CERU/RXR AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1006 PM EDT MON APR 20 2015 .SYNOPSIS... A COLD FRONT WILL MOVE THROUGH LATER TONIGHT AND BRING AN END TO THE STEADY SHOWERS AND THUNDERSTORMS. A LARGE UPPER LEVEL LOW WILL SET UP OVER ONTARIO AND QUEBEC FOR THE MIDDLE AND LATTER PART OF THE WEEK...USHERING IN UNSEASONABLY COOL AIR WHICH WILL LAST INTO THE WEEKEND OR LONGER. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 10 PM UPDATE...HAVE ALLOWED THE TORNADO WATCH TO EXPIRE. CONVECTION IS STILL ACTIVE OVER THE EASTERN ZONES...BUT TOPS HAVE COME DOWN WITH THE LOSS OF DAYLIGHT AND THE MAIN THREAT NOW WILL BE SMALL HAIL AND BRIEF DOWNPOURS. DID BUMP UP POPS INTO THE WEE HOURS ACCORDING TO THE LATEST RADAR TRENDS AND HRRR WHICH SHOW MORE SHOWERS GATHERING TO OUR SOUTHWEST...SLATED TO MOVE THROUGH OVER THE NEXT 3-6 HOURS. SFC COLD FRONT NOW CROSSING THE PA/OHIO BORDER AND WILL PUSH EAST ACROSS THE ENTIRE CWA BY 06Z. THE COOLER MOIST UPSLOPE FLOW BEHIND THE FRONT WILL CREATE PLENTY OF LOW STRATUS ACROSS THE WRN ALLEGHENIES...WHILE MOST OF THE CENTRAL VALLEY REGION WILL FLUCTUATE BETWEEN SCT AND BKN CONDITIONS FOR THE REST OF THE OVERNIGHT. MIN TEMPS WILL RANGE FROM THE LOWER 40S ACROSS THE LAURELS AND NW MTNS...TO THE LOWER 50S IN THE SE. WESTERLY WIND WILL INCREASE AND GUST TO THE MID AND UPPER 20KT RANGE LATE TONIGHT...SIMILAR TO WHAT WE/RE CURRENTLY SEEING ACROSS CENTRAL AND ERN OHIO. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... COLD ADVECTION AND WESTERLY UPSLOPE FLOW WILL LEAD TO SCT SHRA OVER THE NW INTO THE DAY ON TUESDAY...WITH VARIABLE AMOUNTS OF CLOUDS AND SPRINKLES W/ISOLATED SHRA ALONG AND JUST TO THE SE OF THE I-99/RT 220 CORRIDOR. MOSTLY SUNNY SKIES EXPECTED FOR THE FAR SE ZONES. MAXES TUESDAY WILL BE AROUND 50F IN THE NW AND PERHAPS THE LAURELS AS WELL. THE LOWER SUSQ WILL PROBABLY REACH THE LOWER 60S. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... THE LONG TERM PATTERN WILL BE DOMINATED BY A LARGE UPPER LEVEL LOW MOVING THROUGH THE NORTHERN GREAT LAKES...AND THROUGH SOUTHERN CANADA MIDWEEK TO THE WEEKEND. THERE IS GOOD MODEL CONSENSUS THROUGH THE MID RANGE PERIOD. AFTER THE FRONT LIFTS OUT BY TUESDAY MORNING THE UPPER LOW HANGS AROUND S CANADA/NEW ENGLAND FOR SEVERAL DAYS KEEPING FAIRLY BRISK W/NW FLOW ACROSS PA. THIS WILL BRING A STEADY STREAM OF COLDER AIR AS TEMPS SLOWLY SLIP A BIT LOWER EACH DAY WITH BELOW NORMAL READINGS FOR A SEVERAL DAY PERIOD LINGERING INTO NEXT WEEKEND. PROXIMITY OF UPPER LOW WILL ALSO KEEP MENTION OF SCT SHOWERS IN THE FORECAST. A SHORTWAVE SHOULD DROP THROUGH THE REGION WEDNESDAY AFTERNOON INTO THURSDAY MORNING. THIS COULD DROP EVEN COLDER AIR INTO THE REGION BRINGING THE POSSIBILITY OF SNOW TO THE NW TO THE CENTRAL REGIONS OF PA. THE MODELS ARE BECOMING CLOSER TO A CONSENSUS SOLUTION...HOWEVER SOLUTION IS TRENDING TOWARD THE UPPER LEVEL LOW TO BECOME QUASI-STATIONARY AND SLOWLY SPINNING OVER QUEBEC.WITH ONLY A SLIGHT CHANCE FOR PRECIPITATION NEXT WEEKEND. THE MOVEMENT OF THE LOW WILL DOMINATE THE PATTERN NEXT WEEK WITH IT POSSIBLY RETROGRADING AND SWINGING ANOTHER TROUGH THROUGH THE REGION NEXT WEEK. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... A STRONG SFC COLD FRONT PUSHES EAST ACROSS ALL AIRFIELDS BETWEEN 02Z-07Z TUESDAY. COLDER AND MOIST WESTERLY UPSLOPE FLOW IN THE WAKE OF THE FRONT WILL QUICKLY LOWER CIGS AT KJST AND KBFD BACK DOWN INTO THE IFR OR LIFR RANGE TONIGHT AND EARLY TUESDAY WITH AREAS OF MVFR LINGERING DURING THE DAY TUESDAY. FOR THE SUSQ VALLEY AIRFIELDS...VSBYS WILL BE VFR TO BRIEF MVFR IN SHRA/TSRA TONIGHT...WHILE CIGS IN THE MVFR RANGE SHOULD BE FAIRLY WIDESPREAD ACROSS THE CENTRAL MTNS AS THE MUCH COOLER AIR PUSHES IN. BKN CIGS IMPROVE TO MAINLY VFR BY LATE MORNING TUESDAY ACROSS THIS SAME REGION. OUTLOOK... TUE-FRI...PERSISTENT NW FLOW PATTERN EACH DAY WILL FAVOR MVFR CIGS OVER THE NW AIRSPACE IN ZOB SECTOR...WITH MAINLY VFR CONDITIONS PREVAILING IN ZNY DOMAIN. SCT SHOWERS WILL BE POSSIBLE ACROSS ALL OF THE AIRSPACE THROUGH THE REMAINDER OF THE WEEK. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/LAMBERT NEAR TERM...LA CORTE/LAMBERT SHORT TERM...LAMBERT/CERU LONG TERM...CERU/RXR AVIATION...LAMBERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1221 PM EDT SUN APR 19 2015 .SYNOPSIS... A WARM FRONT AND UPPER LEVEL DISTURBANCE APPROACHING FROM THE TENNESSEE VALLEY WILL BRING A SOAKING RAIN TO THE REGION TONIGHT AND EARLY MONDAY. ADDITIONAL SHOWERS AND SCATTERED THUNDERSTORMS WILL ACCOMPANY A COLD FRONT AS IT PUSHES EAST ACROSS THE STATE MONDAY AFTERNOON AND EVENING. A LARGE UPPER LEVEL LOW WILL SET UP OVER ONTARIO AND QUEBEC FOR THE MIDDLE AND LATTER PART OF THE WEEK...USHERING IN UNSEASONABLY COOL AIR WHICH WILL LAST INTO THE WEEKEND OR LONGER. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... EARLIER...THICKER CIRROSTRATUS HAS THINNED ACROSS MUCH OF CENTRAL AND NEPA...BUT THIS WINDOW WILL BE FLEETING AS THICKENING MID AND HIGH CLOUDS STREAM IN QUICKLY FROM THE SW DURING THE MID TO LATE AFTERNOON HOURS...WITH THE ONSET OF RAIN 4-6 HOURS AFTERWARD. THE DECENT AMOUNT OF SUNSHINE HAS HELPED TO BOOST TEMPS A FEW-SVRL DEG F ABOVE FCST HOURLY VALUES DURING THE LATE MORNING...BUT NOT MUCH ABOVE ACTUAL FCST HIGHS FOR TODAY. SOME MAX TEMP TWEAKS WERE DONE TO THE GRIDDED FCST DATABASE. OVERALL...A RATHER NICE EARLY SPRING AFTERNOON...WITH A LIGHT TO MODERATE SERLY BREEZE AND HIGH TEMPS RANGING FROM AROUND 60F ACROSS THE HIGHER TERRAIN OF THE NORTH AND WEST...TO THE UPPER 60S THROUGHOUT MUCH OF THE SUSQ VALLEY. LATEST MODEL TIMING OF THE LEADING...NE EDGE OF RAIN /INCLUDING THE 12Z NAM...09Z SREF...AND LATEST 14Z HRRR RUN/ SUGGESTS THE BULK OF THE REGION WILL BE DRY FOR MUCH OF THE DAY. FAR SOUTHWESTERN AREAS WILL LIKELY SEE SHOWERS BEGIN AROUND 5 PM /21Z/...WHILE THE ONSET OF RAIN/SHOWERS MOVES TO NEAR A KBFD...TO KUNV AND KMRB LINE AROUND 01Z MONDAY...THEN ACROSS THE SUSQ VALLEY BETWEEN 03Z-05Z MONDAY. && .SHORT TERM /8 PM THIS EVENING THROUGH MONDAY NIGHT/... LITTLE TO NO CHANGE WAS NECESSARY FROM THE PREVIOUS FEW FORECAST CYCLES FOR THIS SHORT TERM PERIOD. THE MAIN CHANGE WAS TO FURTHER REFINE THE TIMING AND TO SHOW A SLIGHTLY MORE-OBVIOUS 4-6HR BREAK BETWEEN THE OVERNIGHT/MORNING RAIN AND THE STORMS IN THE AFTERNOON/EVENING. MINS WILL BE HELD UP AS THE WINDS WILL BE BREEZY. USUALLY...CENTRAL PA DOES NOT GET STRONG WIND GUSTS DURING STABLE SERLY FLOW RAIN EVENTS. SO THOUGHTS OF A WIND ADVY WERE DISCOUNTED RATHER EARLY IN THE FORECAST PROCESS TONIGHT. HOWEVER...THE STRONG LOW AND MID LEVEL FLOW WILL BUMP THE PWATS INTO THE 1-1.5 INCH RANGE TONIGHT AND MONDAY. THUS...RAIN COULD BE HEAVY AT TIMES. WITH THE ADDITIONAL TSRA MON PM...THE QPF REACHES BETWEEN 0.75 AND 1.25 INCHES OVER A LARGE PORTION OF THE AREA. BUT THE STREAM FLOWS ARE REALLY LOW AND NO THUNDER TONIGHT SHOULD TRANSLATE INTO NO FLOOD WORRIES OTHER THAN SOME PONDING OF WATER ON ROADS AND A FEW SMALL CREEKS AT BANKFULL. THINGS ARE GROWING NICELY NOW IN THE SE AND EVEN LOCALLY IN HAPPY VALLEY WHICH SHOULD TAKE UP PLENTY OF WATER COMPARED TO JUST TWO WEEKS AGO. SPC HAS PLACED ALL OF THE AREA INTO MRGL RISK AND BROUGHT THE DAY2 SLGT RISK INTO SRN PA...RIGHTFULLY SO. THE BREAK AND ASSOCIATED BREAKS IN THE CLOUDS/WARM SECTOR ON MONDAY WILL LEAD TO GOOD HEATING AND THE FRONT/FORCING COMES THROUGH AT AN OPPORTUNE TIME TO GRAB THE MAX CAPES AND MIN STABILITY. CAPES MAY BE AROUND 1500J/KG AND LI/S DROP TO -3 TO -5. WIND PROFILES ARE MAINLY MULTI-CELLULAR - BUT WITH THE WARM FRONT LIKELY CUTTING THROUGH THE AREA AT THE TIME...WILL NEED TO KEEP AN EYE OUT FOR ROTATING STORMS - ESPECIALLY IF THEY OCCUR ON OR NEAR LLVL BOUNDARIES. && .LONG TERM /TUESDAY THROUGH SUNDAY/... BEHIND THE COLD FRONT MIDWEEK...THE UPPER LOW HANGS AROUND S CANADA/NEW ENGLAND FOR SEVERAL DAYS KEEPING FAIRLY BRISK W/NW FLOW ACROSS PA. THIS WILL BRING A STEADY STREAM OF COLDER AIR AS TEMPS SLOWLY SLIP A BIT LOWER EACH DAY WITH BELOW NORMAL READINGS FOR A SEVERAL DAY PERIOD LINGERING INTO NEXT WEEKEND. PROXIMITY OF UPPER LOW WILL ALSO KEEP MENTION OF SCT SHOWERS IN THE FORECAST... MAINLY DURING THE DAYTIME HOURS. WEDNESDAY MAY HOLD A FAST-MOVING SHORT-WAVE WHICH COULD PRODUCE WHITE PRECIP - BUT DURING THE MIDDLE OF THE DAY. && .AVIATION /16Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS WILL PREVAIL MUCH OF THE DAY...BUT RAPIDLY DETERIORATE FROM SOUTHWEST TO NORTHEAST TONIGHT. EXPECT RESTRICTIONS TO REACH THE FIRST CENTRAL PENNSYLVANIA AIRFIELDS AROUND 00Z MONDAY /KJST/. TIGHTENING GRADIENT LATER TODAY AND TONIGHT AHEAD OF AN APPROACHING COLD FRONT WILL PRODUCE GUSTY WINDS...AND LOW LEVEL WIND SHEAR CONDITIONS. THESE HAVE NOW BEEN ADDED TO ALL TAFS STARTING BETWEEN 00 AND 04Z. RAIN AND WIDESPREAD IFR TO LIFR TONIGHT INTO MONDAY...BEFORE THE PRECIPITATION BECOMES MORE SHOWERY WITH THE APPROACH OF THE FRONT. THIS COLD FRONT WILL ALSO INTRODUCE THE CHANCE OF THUNDERSTORMS MONDAY TO THE ENTIRE REGION. OUTLOOK... MON...WIDESPREAD RESTRICTIONS IN RAIN EARLY...SOME IMPROVEMENT IN THE AFTERNOON...BUT TSRA POSSIBLE. TUE- THU...UNSETTLED WITH NW FLOW EACH DAY...WITH AREAS OF RESTRICTED CIGS/VSBYS IN SHRA IN THE WESTERN AND NORTHERN MOUNTAINS...SPOTTY RESTRICTIONS IN MORE SCATTERED SHRA IN CENTRAL MOUNTAINS...AND MAINLY VFR IN THE EAST AND SOUTHEAST. && .FIRE WEATHER... SFC WIND FROM THE SOUTHEAST WILL BE 10-15 KTS WITH GUSTS AROUND 20KT ACROSS THE HIGHER TERRAIN OF SOUTHERN AND WESTERN PENN THIS AFTERNOON...WHILE THE WIND STAYS A BIT LIGHTER ACROSS THE NE HALF OF THE STATE - WHERE REL HUMIDITY IS EXPECTED TO DIP TO/STAY BELOW 30 PERCENT FOR THE REST OF THE AFTERNOON. GUSTS OF 15 TO 20 MPH ARE POSSIBLE IN THE NORTHEAST BY LATE AFTERNOON. BUT THE GUSTS OVER 20MPH WILL ONLY MATCH UP WITH THE LOW RH/S FOR AN HOUR OR TWO AT THE MOST AND ONLY IN A SMALL PORTION OF THE NORTHERN MOUNTAINS. THEREFORE...PLAN IS AT THIS POINT - NOT TO ISSUE A RED FLAG WARNING. A SIGNIFICANT RAINFALL IS EXPECTED STARTING THIS EVENING AND LASTING UNTIL A COLD FRONT PUSHES THROUGH ON MONDAY AFTERNOON AND EVENING. COOLER TEMPERATURES FOR THE REST OF THE WEEK WILL LIKELY LEAD TO HIGHER RH/S AND KEEP FIRE WEATHER CONDITIONS BELOW CRITICAL. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...DANGELO/LAMBERT LONG TERM...CERU/RXR AVIATION...JUNG FIRE WEATHER...LAMBERT
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
200 PM CDT SUN APR 19 2015 .DISCUSSION...SURFACE MAP AT 18Z SHOWS A 1000 MB LOW CENTERED OVER SOUTHERN ILLINOIS, WITH A WARM FROM SITUATED TO OUR NORTH, A COLD FRONT STILL WEST OF THE MISSISSIPPI RIVER, AND A PRE-FRONTAL TROUGH JUST NOW CROSSING THE TENNESSEE RIVER THAT IS PROVIDING THE FOCUS FOR A DEVELOPING LINE OF CONVECTION. SATELLITE IMAGERY IS STARTING TO SHOW SOME BREAKS IN THE CLOUDS, ESPECIALLY WEST OF NASHVILLE. LAPS SOUNDING FOR BNA AT 18Z SHOWS WEAK INSTABILITY, WITH A LIFTED INDEX OF -3.3 AND A CAPE OF 962 J/KG. ATMOSPHERE REMAINS SUFFICIENTLY MOIST, WITH PRECIPITABLE WATER OF 1.44 INCHES AND A K-INDEX OF 34. LATEST HRRR SHOWS SCATTERED CELLS ACROSS MIDDLE TENNESSEE UNTIL A MORE ORGANIZED LINE OF CONVECTION COMES THROUGH WITH THE COLD FRONT BETWEEN 04Z AND 09Z. GIVEN THE TIMING OF THE FRONT, THE POTENTIAL FOR WIDESPREAD SEVERE STORMS APPEARS LOW, ALTHOUGH MIDDLE TENNESSEE DOES REMAIN UNDER A SLIGHT RISK OF SEVERE WEATHER TODAY AND TONIGHT, SO ISOLATED CASES OF SEVERE ACTIVITY ARE STILL POSSIBLE. AFTER A FEW LINGERING SHOWERS ON MONDAY, LOOK FOR A BRIEF RESPITE ON TUESDAY BEFORE THE NEXT COLD FRONT DROPS SOUTHWARD THROUGH MIDDLE TENNESSEE WEDNESDAY AND THURSDAY. GIVEN THAT THE UPPER FLOW ACROSS THE REGION WILL REMAIN EITHER CYCLONIC OR ZONAL, WARM ADVECTION WILL BE HARD TO COME BY, AND SO TEMPERATURES DURING THE NEXT 7 DAYS WILL REMAIN AT OR BELOW NORMAL. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 60 67 43 72 / 50 40 10 10 CLARKSVILLE 57 66 41 71 / 50 40 05 10 CROSSVILLE 58 62 42 63 / 50 60 20 10 COLUMBIA 59 68 43 73 / 60 30 10 10 LAWRENCEBURG 57 67 43 72 / 60 20 10 10 WAVERLY 57 68 42 72 / 60 30 05 10 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ROSE
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1135 PM CDT SAT APR 18 2015 .UPDATE...FOR AVIATION. && .AVIATION... 06Z TAFS...BNA/CKV/CSV...A LOW PRESSURE SYSTEM AND WARM FRONT WILL LIFT INTO MID TN OVERNIGHT BRINGING WIDESPREAD SHOWERS. LOOK FOR -SHRA WITH MVFR CIGS/VSBYS TO DEVELOP AROUND 08Z...WITH TEMPO IFR AND SOME LIFR 10Z-15Z. THE MAIN BAND OF MOISTURE WILL LIFT NORTH OF MID TN BY 18Z. ANOTHER SYSTEM WILL APPROACH SUNDAY AFTERNOON AND EVENING WITH SCATTERED TSRA...SOME POSSIBLY SEVERE. 13 && .PREV DISCUSSION... /ISSUED 1006 PM CDT SAT APR 18 2015/ UPDATE... HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO INCREASE SHWR/TSTM CHANCES FROM SW TO NE REST OF EVENING AND OVERNIGHT. TWEAKED HRLY TEMP...DEWPOINT... SKY...AND WIND SPEED/DIRECTION GRIDS ALSO. REMAINDER OF FORECAST REMAINS ON TRACK. PREV DISCUSSION... /ISSUED 530 PM CDT SAT APR 18 2015/ UPDATE... HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO REFLECT CURRENT REGIONAL SFC OBS...SATELLITE...AND MOSAIC RADAR TRENDS ALONG WITH THE LATEST IN SHORT RANGE MODEL CONSENSUS...THUS MAINTAINING ISO SHWRS/TSTMS THRU AT LEAST THE MID EVENING HRS. BULK OF SHWR/TSTMS ACTIVITY SHOULD SPREAD FROM THE SW TO THE NE ACROSS THE MID STATE AFTER MIDNIGHT. PREV DISCUSSION.../ISSUED 351 PM CDT SAT APR 18 2015/ DISCUSSION... AS AN UPPER TROUGH CENTERED OVER THE CENTRAL PLAINS MOVES EAST THIS AFTERNOON AND OVERNIGHT IT WILL INFLUENCE SHOWERS AND THUNDERSTORMS TO CONTINUE THEIR TREK NORTHWARD THROUGH MIDDLE TN. HRRR IS FORECASTING SCATTERED AFTERNOON ACTIVITY TO MOVE INTO KENTUCKY AND ANOTHER WAVE OF PRECIP TO SPREAD INTO MIDDLE TENNESSEE FROM THE SOUTH BEFORE MIDNIGHT. PWAT VALUES WILL BE AROUND 1.5 INCHES FOR SEVERAL HOURS OVERNIGHT TONIGHT. WITH THE GROUND ALREADY SATURATED FROM THIS PAST WEEK`S RAINFALL...WE COULD SEE CREEKS AND STREAMS RISE PRETTY QUICKLY DURING THE OVERNIGHT HOURS...WATCH FOR MINOR FLOODING IN LOW LYING AREAS AND PONDING OF WATER ON ROADWAYS OVERNIGHT. WHILE THERE MAY BE STORMS AROUND...NOT EXPECTING ANYTHING STRONG OR SEVERE TONIGHT. BETWEEN LATE SUNDAY MORNING AND EARLY AFTERNOON THE DEEPEST MOISTURE WILL PUSH NORTH OF OUR AREA. LINGERING CLOUD COVER...ESPECIALLY OVER THE NORTHEASTERN PORTION OF THE CWA MAY INHIBIT INSTABILITY...BUT CLOUDS SHOULD BREAK UP ENOUGH DURING THE AFTERNOON HOURS TO ALLOW FOR TEMPERATURES TO WARM INTO THE LOW 70S ALONG THE CUMBERLAND PLATEAU AND MID 70S ELSEWHERE. THIS SHOULD BE WARM ENOUGH TO INITIATE ISOLATED TO SCATTERED STORMS THROUGHOUT THE AFTERNOON. CURRENTLY SPC HAS THE MID-STATE IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS FOR SUNDAY AFTERNOON THROUGH SUNDAY NIGHT. THE MAIN THREAT WITH ANY STORMS DURING THIS TIME FRAME WILL BE DAMAGING WINDS AND HAIL. WE COULD SEE A COUPLE OF ROUNDS OF THUNDERSTORMS OVERNIGHT SUNDAY NIGHT AHEAD OF A SHORTWAVE AND ITS ASSOCIATED SURFACE LOW...WHICH STRENGTHEN OVER SOUTHERN ILLINOIS AND HEAD NORTHEAST ON MONDAY. THE FRONTAL PASSAGE ASSOCIATED WITH THE AFOREMENTIONED LOW WILL OCCUR ON MONDAY AND WILL ALLOW FOR TEMPERATURES TO COOL INTO THE 40S OVERNIGHT MONDAY NIGHT. ALL PRECIP SHOULD PUSH EAST OF THE TENNESSEE VALLEY TUESDAY NIGHT. A SURFACE HIGH MOVES IN ON TUESDAY AND GIVES US A MUCH NEEDED DRY AND RELATIVELY COOL DAY WITH HIGH TEMPERATURES IN THE MID 60S. THE NEXT CHANCE OF PRECIP ENTERS THE FORECAST WEDNESDAY EVENING AS A WEAK FRONT BRINGS A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THE AREA. COULD SEE A BREAK ON FRIDAY AS THAT MOISTURE PUSHES SOUTH...THEN ANOTHER SURFACE LOW BRINGS ADDITIONAL THUNDERSTORM CHANCES FRIDAY NIGHT. && .OHX WATCHES/WARNINGS/ADVISORIES...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1059 PM CDT MON APR 20 2015 .AVIATION... SHOWERS AND POSSIBLY A THUNDERSTORM COULD IMPACT KAMA UNTIL AROUND 07Z. OTHERWISE...VFR CEILINGS EXPECTED OVERNIGHT. LIGHT SURFACE WINDS EXPECTED TUESDAY MORNING. SOUTHERLY SURFACE WINDS EXPECTED TUESDAY AFTERNOON WITH HIGH-BASED CUMULUS. SHOWERS AND THUNDERSTORMS EXPECTED TO NOT MAKE MUCH OF AN IMPACT ON TERMINALS THROUGH 06Z WEDNESDAY...WITH BETTER PROSPECTS FOR CONVECTION JUST BEYOND THE DURATION OF THIS FORECAST. COCKRELL && .PREV DISCUSSION... /ISSUED 643 PM CDT MON APR 20 2015/ UPDATE... UPDATED GRAPHICAL FORECASTS TO INCLUDE ISOLATED THUNDER THIS EVENING. LIGHTNING STRIKES CURRENTLY BEING OBSERVED IN NORTHWEST PART OF FORECAST AREA AND IN EASTERN NEW MEXICO. WITH STRENGTH OF SHORTWAVE TROF MOVING IN FROM THE WEST AT THIS TIME...BELIEVE THAT ADDITIONAL THUNDER CAN BE EXPECTED. UPDATED TEXT PRODUCTS HAVE BEEN ISSUED. COCKRELL AVIATION... SHORTWAVE TROF WILL CAUSE SHOWERS AND ISOLATED THUNDERSTORMS TO DEVELOP THIS EVENING AND OVERNIGHT. EXPECTING VFR OVERCAST AND MAINLY SHOWERS TO IMPACT ALL TERMINALS. PRECIPITATION EXPECTED TO END BY 09Z TUESDAY WITH CONTINUED VFR CONDTIONS THEREAFTER. COCKRELL PREV DISCUSSION... /ISSUED 250 PM CDT MON APR 20 2015/ SHORT TERM... (TONIGHT) THE SURFACE HIGH WILL CONTINUE TO SLIDE EAST ALLOWING FOR SOUTHERLY FLOW TO BRING GULF MOISTURE INTO THE AREA AND BRINGING UPSLOPING WINDS. THE UPPER LEVEL RIDGE OFF TO THE WEST IS ALSO MOVING EASTWARD AND BRINGING A VORT LOBE THROUGH THE AREA. THESE TWO LIFTING MECHANISMS WILL CREATE CHANCES FOR RAIN SHOWERS OVER THE CENTRAL TO SOUTHERN TX PANHANDLE BETWEEN 6PM THROUGH 1AM. PREFERRED THE GFS MODEL OVER NAM AS IT CAPTURED QPF LOCATIONS BETTER AS IT AGREED WITH TEXAS TECH WRF AND HRRR MODELS. THUS WENT WITH MAV GUIDANCE ON WINDS AND DEW POINTS. TONIGHT SHOULD BE WARMER THAN LAST NIGHT DUE TO INCREASED CLOUD COVER AND THE SOUTHERLY FLOW CREATING LOWS IN THE UPPER 30S TO MID 40S OVERNIGHT. MB/CLK LONG TERM... (TOMORROW THROUGH SUNDAY) THERE IS A VERY LOW PROBABILITY OF RESIDUAL CONVECTION IN THE FAR EAST TOMORROW MORNING AS SUBTLE MID-LEVEL WAVE EXITS THE AREA. LATER IN THE DAY WEAK HEIGHT FALLS OCCUR JUST TO OUR WEST AS CLOSED LOW IN THE SOUTHWEST CONUS DEEPENS. ALTHOUGH SUBTLE (AND DESPITE STILL RELATIVELY WEAK MEAN WESTERLY-NORTHWESTERLY FLOW) THIS SHOULD STILL BE SUFFICIENT TO FORCE LEE SURFACE PRESSURE FALLS AND START THE NORTHWESTWARD MOVEMENT OF LOW LEVEL MOISTURE BACK INTO THE AREA. CURRENT SURFACE OBSERVATION SHOW OFF SHORE FLOW WITH RICH LOW LEVEL MOISTURE LIMITED TO COASTAL AREAS AND DEEP SOUTH TEXAS. SHORT RANGE GUIDANCE GENERALLY SHOWS THE EQUATORWARD PUSH OF THE COLD FRONT HAS STOPPED AS SURFACE FLOW VEERING IN RESPONSE TO STRENGTHENING/SOUTHEASTWARD MOVING SURFACE HIGH IN THE LOWER MISSISSIPPI VALLEY. TIMING OF RELATIVELY RICH LOW-LEVEL MOISTURE IS SOMEWHAT IN QUESTION GIVEN EVAPOTRANSPIRATIVE PARAMETRIZATION POSSIBLY EXAGGERATING QUALITY OF MOISTURE RETURN INITIALLY. AM CONCERNED THAT GOOD QUALITY MOISTURE RETURN MAY BE TOO RAPID THROUGH LATE AFTERNOON/EARLY EVENING. SOME CONVECTION COULD FORM BY LATE AFTERNOON BUT COVERAGE OF MEASURABLE PRECIPITATION SHOULD BE LIMITED NECESSITATING ONLY SLIGHT CHANCE PROBABILITIES THROUGH EARLY EVENING. 0-2KM THETA-E VALUES TREND UPWARD NOTABLY AFTER DARK AND WITH INCREASING LARGE SCALE FORCING PRECIPITATION PROBABILITIES SHOULD BE MARKEDLY HIGHER DURING THE EVENING AND OVERNIGHT PERIOD...ESPECIALLY ACROSS THE EASTERN PORTION OF THE FORECAST AREA. A COLD FRONT FORCED BY A NORTHERN STREAM WAVE WILL REACH OUR AREA BY WEDNESDAY MORNING WITH UNCERTAINTY INCREASING SOMEWHAT BY THIS TIME. THE BOUNDARY WILL PROBABLY PROGRESS SLOWLY SOUTHWARD THROUGH THE AREA BY EVENING WITH WEAK ISENTROPIC LIFT ATOP SHALLOW COOL LAYER RESULTING IN CONVECTION. HAVE DIMINISHED PROBABILITIES OVERNIGHT AS MOIST UPGLIDE OVER THE BOUNDARY WEAKENS AND MID LEVEL HEIGHTS RISE SOME. CONFIDENCE IS A LITTLE HIGHER IN THE EXTENDED GIVEN BETTER AGREEMENT OF MEDIUM RANGE DETERMINISTIC GUIDANCE AND LESS SPREAD IN THE ENSEMBLE MEMBERS. BY THURSDAY A MUCH MORE SIGNIFICANT MID-UPPER TROUGH IN THE SOUTHWEST APPROACHES CAUSING A FAIRLY DRAMATIC SURFACE RESPONSE THROUGH FRIDAY. STRENGTHENING LEE TROUGH/LOW WILL RESULT IN INCREASED LOW-LEVEL MOIST FLOW AGAIN AND WITH MIXING BY THURSDAY AFTERNOON THE DRYLINE WILL SHARPEN ACROSS THE AREA. THE BEST OPPORTUNITY FOR PRECIPITATION WITH THIS SYSTEM WILL BE THURSDAY AFTERNOON AND EVENING AHEAD OF SHARPENING DRYLINE WHICH SEEMS MOST LIKELY TO BE POSITIONED NORTH-SOUTH ACROSS THE CENTRAL PORTION OF THE PANHANDLES. GIVEN THE PROGRESSIVE NATURE OF THIS SYSTEM A PERIOD OF POST-DRYLINE DEEP MIXING MAY OCCUR FRIDAY AFTERNOON WITH CONCERNS FOR FIRE WEATHER POSSIBLY DEVELOPING THEN. BY THE WEEKEND IN THE WAKE OF THIS WAVE A QUASI-ZONAL UPPER FLOW PATTERN EVOLVES WITH SOME FAIRLY SIZABLE PERTURBATIONS SHOWING UP IN MEDIUM RANGE GUIDANCE...PARTICULARLY AROUND SUNDAY. ALTHOUGH TIMING IS UNCERTAIN AT THIS POINT IN TIME...DID MAINTAIN LOW PRECIPITATION PROBABILITIES ON SUNDAY. BRB && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 03/15
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
643 PM CDT MON APR 20 2015 .UPDATE... UPDATED GRAPHICAL FORECASTS TO INCLUDE ISOLATED THUNDER THIS EVENING. LIGHTNING STRIKES CURRENTLY BEING OBSERVED IN NORTHWEST PART OF FORECAST AREA AND IN EASTERN NEW MEXICO. WITH STRENGTH OF SHORTWAVE TROF MOVING IN FROM THE WEST AT THIS TIME...BELIEVE THAT ADDITIONAL THUNDER CAN BE EXPECTED. UPDATED TEXT PRODUCTS HAVE BEEN ISSUED. COCKRELL && .AVIATION... SHORTWAVE TROF WILL CAUSE SHOWERS AND ISOLATED THUNDERSTORMS TO DEVELOP THIS EVENING AND OVERNIGHT. EXPECTING VFR OVERCAST AND MAINLY SHOWERS TO IMPACT ALL TERMINALS. PRECIPITATION EXPECTED TO END BY 09Z TUESDAY WITH CONTINUED VFR CONDTIONS THEREAFTER. COCKRELL && .PREV DISCUSSION... /ISSUED 250 PM CDT MON APR 20 2015/ SHORT TERM... (TONIGHT) THE SURFACE HIGH WILL CONTINUE TO SLIDE EAST ALLOWING FOR SOUTHERLY FLOW TO BRING GULF MOISTURE INTO THE AREA AND BRINGING UPSLOPING WINDS. THE UPPER LEVEL RIDGE OFF TO THE WEST IS ALSO MOVING EASTWARD AND BRINGING A VORT LOBE THROUGH THE AREA. THESE TWO LIFTING MECHANISMS WILL CREATE CHANCES FOR RAIN SHOWERS OVER THE CENTRAL TO SOUTHERN TX PANHANDLE BETWEEN 6PM THROUGH 1AM. PREFERRED THE GFS MODEL OVER NAM AS IT CAPTURED QPF LOCATIONS BETTER AS IT AGREED WITH TEXAS TECH WRF AND HRRR MODELS. THUS WENT WITH MAV GUIDANCE ON WINDS AND DEW POINTS. TONIGHT SHOULD BE WARMER THAN LAST NIGHT DUE TO INCREASED CLOUD COVER AND THE SOUTHERLY FLOW CREATING LOWS IN THE UPPER 30S TO MID 40S OVERNIGHT. MB/CLK LONG TERM... (TOMORROW THROUGH SUNDAY) THERE IS A VERY LOW PROBABILITY OF RESIDUAL CONVECTION IN THE FAR EAST TOMORROW MORNING AS SUBTLE MID-LEVEL WAVE EXITS THE AREA. LATER IN THE DAY WEAK HEIGHT FALLS OCCUR JUST TO OUR WEST AS CLOSED LOW IN THE SOUTHWEST CONUS DEEPENS. ALTHOUGH SUBTLE (AND DESPITE STILL RELATIVELY WEAK MEAN WESTERLY-NORTHWESTERLY FLOW) THIS SHOULD STILL BE SUFFICIENT TO FORCE LEE SURFACE PRESSURE FALLS AND START THE NORTHWESTWARD MOVEMENT OF LOW LEVEL MOISTURE BACK INTO THE AREA. CURRENT SURFACE OBSERVATION SHOW OFF SHORE FLOW WITH RICH LOW LEVEL MOISTURE LIMITED TO COASTAL AREAS AND DEEP SOUTH TEXAS. SHORT RANGE GUIDANCE GENERALLY SHOWS THE EQUATORWARD PUSH OF THE COLD FRONT HAS STOPPED AS SURFACE FLOW VEERING IN RESPONSE TO STRENGTHENING/SOUTHEASTWARD MOVING SURFACE HIGH IN THE LOWER MISSISSIPPI VALLEY. TIMING OF RELATIVELY RICH LOW-LEVEL MOISTURE IS SOMEWHAT IN QUESTION GIVEN EVAPOTRANSPIRATIVE PARAMETRIZATION POSSIBLY EXAGGERATING QUALITY OF MOISTURE RETURN INITIALLY. AM CONCERNED THAT GOOD QUALITY MOISTURE RETURN MAY BE TOO RAPID THROUGH LATE AFTERNOON/EARLY EVENING. SOME CONVECTION COULD FORM BY LATE AFTERNOON BUT COVERAGE OF MEASURABLE PRECIPITATION SHOULD BE LIMITED NECESSITATING ONLY SLIGHT CHANCE PROBABILITIES THROUGH EARLY EVENING. 0-2KM THETA-E VALUES TREND UPWARD NOTABLY AFTER DARK AND WITH INCREASING LARGE SCALE FORCING PRECIPITATION PROBABILITIES SHOULD BE MARKEDLY HIGHER DURING THE EVENING AND OVERNIGHT PERIOD...ESPECIALLY ACROSS THE EASTERN PORTION OF THE FORECAST AREA. A COLD FRONT FORCED BY A NORTHERN STREAM WAVE WILL REACH OUR AREA BY WEDNESDAY MORNING WITH UNCERTAINTY INCREASING SOMEWHAT BY THIS TIME. THE BOUNDARY WILL PROBABLY PROGRESS SLOWLY SOUTHWARD THROUGH THE AREA BY EVENING WITH WEAK ISENTROPIC LIFT ATOP SHALLOW COOL LAYER RESULTING IN CONVECTION. HAVE DIMINISHED PROBABILITIES OVERNIGHT AS MOIST UPGLIDE OVER THE BOUNDARY WEAKENS AND MID LEVEL HEIGHTS RISE SOME. CONFIDENCE IS A LITTLE HIGHER IN THE EXTENDED GIVEN BETTER AGREEMENT OF MEDIUM RANGE DETERMINISTIC GUIDANCE AND LESS SPREAD IN THE ENSEMBLE MEMBERS. BY THURSDAY A MUCH MORE SIGNIFICANT MID-UPPER TROUGH IN THE SOUTHWEST APPROACHES CAUSING A FAIRLY DRAMATIC SURFACE RESPONSE THROUGH FRIDAY. STRENGTHENING LEE TROUGH/LOW WILL RESULT IN INCREASED LOW-LEVEL MOIST FLOW AGAIN AND WITH MIXING BY THURSDAY AFTERNOON THE DRYLINE WILL SHARPEN ACROSS THE AREA. THE BEST OPPORTUNITY FOR PRECIPITATION WITH THIS SYSTEM WILL BE THURSDAY AFTERNOON AND EVENING AHEAD OF SHARPENING DRYLINE WHICH SEEMS MOST LIKELY TO BE POSITIONED NORTH-SOUTH ACROSS THE CENTRAL PORTION OF THE PANHANDLES. GIVEN THE PROGRESSIVE NATURE OF THIS SYSTEM A PERIOD OF POST-DRYLINE DEEP MIXING MAY OCCUR FRIDAY AFTERNOON WITH CONCERNS FOR FIRE WEATHER POSSIBLY DEVELOPING THEN. BY THE WEEKEND IN THE WAKE OF THIS WAVE A QUASI-ZONAL UPPER FLOW PATTERN EVOLVES WITH SOME FAIRLY SIZABLE PERTURBATIONS SHOWING UP IN MEDIUM RANGE GUIDANCE...PARTICULARLY AROUND SUNDAY. ALTHOUGH TIMING IS UNCERTAIN AT THIS POINT IN TIME...DID MAINTAIN LOW PRECIPITATION PROBABILITIES ON SUNDAY. BRB && .PRELIMINARY POINT TEMPS/POPS... AMARILLO TX 43 76 49 73 51 / 40 20 30 20 20 BEAVER OK 43 76 48 63 48 / 30 10 30 40 20 BOISE CITY OK 39 73 45 63 47 / 30 10 30 30 20 BORGER TX 46 77 53 72 52 / 50 20 30 30 20 BOYS RANCH TX 43 78 47 74 50 / 40 20 20 20 20 CANYON TX 43 77 47 75 50 / 20 20 20 20 20 CLARENDON TX 46 76 50 74 52 / 20 20 30 30 20 DALHART TX 41 75 44 70 47 / 50 10 30 30 20 GUYMON OK 41 76 46 64 48 / 30 10 30 40 20 HEREFORD TX 43 78 43 80 49 / 20 10 20 20 20 LIPSCOMB TX 45 75 52 65 50 / 30 20 40 40 20 PAMPA TX 44 74 49 69 50 / 50 20 40 30 20 SHAMROCK TX 47 75 52 70 53 / 30 20 40 40 30 WELLINGTON TX 47 77 55 74 54 / 20 20 40 40 20 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 03/15
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1239 AM CDT SUN APR 19 2015 .DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. && .AVIATION...WIND SPEEDS ARE DECREASING AS TEMPERATURES COOL TONIGHT. CLEAR SKIES WILL OPEN UP FOR SOME AREAS OF GROUND FOG TO DEEPEN THROUGH THE NIGHT AND REFLECTED THAT IN THE TAFS. BRO/HRL WILL LIKELY CONTINUE TO GET WORSE THROUGH THE NIGHT BUT MFE MAY HOLD ON VFR MOST OF THE EVENING WITH A LARGER SFC DEWPOINT DEPRESSION. DRIER AIR JUST ABOVE THE SURFACE SHOULD ALLOW CONDITIONS TO IMPROVE PRETTY QUICKLY THROUGH MID MORNING. THERE IS A CONDITIONAL RISK FOR CONVECTION MAINLY THIS AFTERNOON. /68-JGG/ && .PREV DISCUSSION... /ISSUED 633 PM CDT SAT APR 18 2015/ DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. AVIATION...A FEW SHOWERS HAVE ATTEMPTED TO GET GOING OVER THE COASTAL COUNTIES OF DEEP SOUTH TEXAS...HOWEVER THEY HAVE LARGELY FIZZLED OUT DUE TO A MORE STABLE ATMOSPHERE AIDED BY THE FRIDAY EVENING/NIGHT CONVECTION. CURRENT SATELLITE IMAGERY DOESN/T SHOW ANY CONVECTION IN THE VICINITY OF THE AERODROMES AND THIS HAS BEEN REMOVED FROM THE PREVIOUS TAFS. SURFACE WINDS WILL LIKELY REMAIN TOO STRONG OVERNIGHT TO ALLOW FOR SIGNIFICANT FORMATION OF FOG...BUT A TEMPO HAS BEEN INCLUDED FOR LIGHT FOG DEVELOPMENT FOR NEAR SUNRISE SUNDAY MORNING. PREVIOUSLY-LOWER CEILINGS HAVE BEEN BEEN DUMPED IN FAVOR OF THE MID AND HIGH LEVEL CLOUDINESS STREAMING OVERHEAD OUT OF NEIGHBORING MEXICO. OVERALL...VFR SHOULD BE THE RULE THROUGH THE NEXT 24 HOURS. PREV DISCUSSION... /ISSUED 255 PM CDT SAT APR 18 2015/ SHORT TERM.../NOW THROUGH SUNDAY NIGHT/...A LOW PRESSURE SYSTEM CENTERED OVER EASTERN COLORADO IS MAINTAINING A BROAD AREA OF DIFFLUENT FLOW ALOFT OVER SOUTH CENTRAL TEXAS. ALSO ...A VERY ACTIVE SUB TROPICAL JET WITH SHORTWAVES WITHIN THE FLOW IS MOVING ACROSS SOUTH TX UNDERNEATH THIS LOW. THIS WILL CONTINUE TO PRODUCE NUMEROUS SHOWERS AND THUNDERSTORMS ALONG THE LOWER TEXAS GULF WATERS NORTHEAST INTO THE NORTHWEST GULF COAST. THERE IS AN AREA OF CONVECTION DEVELOPING ALONG A STATIONARY FRONT WHICH IS INTERACTING WITH PLENTY OF DEEP LAYER MOISTURE AND INSTABILITY POOLED ALONG IT. NEAR THE SURFACE DEW POINTS RANGE FROM 70 TO 75 DEGREES AND PRECIPITABLE WATER VALUES IN THE LAST KBRO 12Z SOUNDING SHOWS 1.96 INCHES AND THE LATEST RAP MODEL RUN SHOWS PWATS OF 1.5 TO 1.9 INCHES ESPECIALLY FROM HIDALGO COUNTY NORTHEAST AND EAST TOWARDS THE COAST. IN ADDITION...THE A SLIGHT BREAK IN THE CLOUDS IS ALLOWING FOR TEMPS TO WARM UP FOR THE NEXT FEW HOURS RESULTING IN INCREASE INSTABILITY ACROSS THE AREA. THIS WILL RESULT IN A CONTINUATION OF THE CONVECTION IN THE LATE AFTERNOON THROUGH THE OVERNIGHT HOURS THROUGH MIDNIGHT. THE CONVECTION WILL ALSO BE ENHANCE ALONG THE SIERRA MADRE AND MOVE NORTHEAST WHICH WILL MAKE ITS WAY INTO STARR AND HIDALGO COUNTY LATE EVENING INTO THE OVERNIGHT. THE MAIN THREAT WITH THESE STORMS WILL BE VERY HEAVY DOWNPOURS PRODUCING FLOODING...STRONG DAMAGING WINDS...HAIL AND FREQUENT CG LIGHTNING. INTO SUNDAY THE UPPER LEVEL JET WILL MAKE ITS WAY INTO SOUTH TEXAS PROVIDING SUPPORT FOR SOME CONVECTION TO DEVELOP SUNDAY AFTERNOON. EXPECT THE BEST POTENTIAL TO REMAIN ALONG THE COAST DUE TO THE INSTABILITY IN THE AREA. EXPECT A FEW OF THE STORMS TO BECOME SEVERE. THE CLOSED LOW BECOMES AN OPEN WAVE AS IT MOVES NORTHEAST INTO THE GREAT LAKES SUNDAY NIGHT PUSHING A COLD FRONT BEHIND IT ALONG THE CENTRAL PLAINS. THE CONVECTION WILL BE ENHANCE EVEN MORE OVERNIGHT SUNDAY ASSOCIATED TO THE BOUNDARY AS THE FRONT APPROACHES THE AREA. THE FRONT WILL ARRIVED BY THE END OF THE SHORT TERM OVER THE NORTHERN RANCHLANDS EARLY MONDAY MORNING. LONG TERM.../MONDAY THROUGH SATURDAY/...THE CLOSED LOW THAT HAS BEEN PLAUGING THE REGION WITH INTERMITTENT THUNDERSTORMS FOR THE LAST SEVERAL DAYS OPENS UP AND MERGES WITH A SHARP SHORTWAVE TROUGH UPPER TROUGH MOVING OUT OF CANADA. THE RESULT WILL BE A LARGE SCALE UPPER TROUGH DEVELOPING MONDAY INTO TUESDAY FROM THE NORTHERN PLAINS TO THE MIDWEST EXTENDING SOUTH INTO THE GULF SOUTH. THIS SENDS A COLD FRONT THROUGH SOUTH TEXAS SUNDAY NIGHT MOVING OFFSHORE THE LOWER TEXAS COAST AS EARLY AS SUNRISE MONDAY. MODELS ARE IN GOOD AGREEMENT AND REMAIN VERY CONSISTENT WITH THE EVOLUTION OF THE UPPER LEVEL AND SURFACE FEATURES. MODERATE TO HIGH CONFIDENCE IN THE FORECAST THROUGH TUESDAY MAINTAINS A LOWERING OF TEMPERATURES AND HIGHER CHANCES OF RAINFALL. THE COOLING OF THE LOWER ATMOSPHERE, LOWER LAPSE RATES, WEAKENING INSTABILITY WILL LIMIT THE THUNDERSTORM INTENSITY AND SEVERE WEATHER PROBABILITIES GO WAY LOW. GFS MODEL SOUNDING CONTINUE TO INDICATE THE BEST CHANCE OF THUNDER MONDAY MORNING AS THE FRONTAL BOUNDARY PASSES THROUGH BUT AS THE COOLER SURFACE AIR SETTLES IN THE INSTABILITY QUICKLY WEAKENS. ANY THUNDERSTORMS THAT LINGER INTO THE MONDAY AFTERNOON AND EVENING WILL BE ELEVATED. AS WE MOVE INTO TUESDAY AND THE REST OF THE WEEK THE FRONT INITIALLY REMAINS STATIONARY NEAR OR JUST SOUTH OF THE REGION KEEPING A MOIST EASTERLY FLOW AND POSSIBLY THE HIGHEST CHANCE OF RAIN. BOTH GFS AND ECMWF INDICATE ON AVERAGE THAT TUESDAY WILL HAVE THE BEST COVERAGE OF RAIN. THIS WILL ALSO KEEP TEMPERATURES BELOW NORMAL. AFTER TUESDAY FORECAST TRENDS DOWNWARD ON THE RAIN AND UP WITH THE TEMPERATURES. THE FRONT EVENTUALLY DISSIPATES OR MOVES BACK NORTH AS SHORTWAVE RIDGING BUILDS OVER WESTERN TEXAS WITH THE NEXT UPPER TROUGH APPROACHING THE PACIFIC COAST. GFS AND ECMWF DO LITTLE WITH THIS TROUGH AND IT LOOKS MUCH WEAKER THEN THE LAST FEW TROUGHS. SOME PERTURBATIONS DO ADVANCE THROUGH THE TROUGH AND RIDE ALONG STOUT SOUTHWESTERLY UPPER JET AND MAY SPARK SOME AFTERNOON CONVECTION OVER THE SIERRA MADRE AND THEN DRIFT INTO OUR CWA EACH AFTERNOON AND EVENING. THIS WILL BE INDICATED BY LOW GRADE POPS EACH LATE DAY AND EVENING. MARINE...NOW THROUGH SUNDAY NIGHT...THE SOUTHEAST WINDS WILL REMAIN LIGHT TO VARIABLE WITH LOW SEAS ACROSS THE GULF WATERS. THE MAIN CONCERNED THROUGH THE SHORT TERM WILL CONTINUE TO BE THE CONVECTION OVER THE GULF. THERE IS ENOUGH INSTABILITY IN THE AREA FROM A STATIONARY BOUNDARY PARALLEL TO THE COAST THAT WILL ENHANCE MORE CONVECTION INCREASING LATE THIS AFTERNOON AND CONTINUE OVERNIGHT. SUNDAY...THE POTENTIAL FOR CONVECTION WILL BEGIN TO DEVELOP IN THE AFTERNOON AND CONTINUE OVERNIGHT AS A COLD FRONT IS EXPECTED TO ARRIVED EARLY MONDAY INCREASING THE CHANCE OF RAIN EVEN MORE AND SHIFTING WINDS NORTHERLY. MONDAY THROUGH THURSDAY...COLD FRONT STILL ON TAP FOR EARLY MONDAY AS HIGH PRESSURE BUILDS DOWN THE CENTRAL PLAINS AS A MID LEVEL TROUGH DEEPENS INTO THE GULF SOUTH STATES. NORTHEAST WINDS INCREASE APPROACHING SMALL CRAFT ADVISORY CONDITIONS MONDAY AFTERNOON. SEAS TO RESPOND AND BUILD UPWARDS TO 6 FEET BY MONDAY NIGHT. MODERATE NORTHEAST TO EAST WINDS PERSIST TUESDAY AS THE FRONT BECOMES STATIONARY AND HIGH PRESSURE EXPANDS OVER THE CENTRAL GULF. A RETURN TO SOUTHEAST WINDS WEDNESDAY WITH A GRADUAL INCREASE THROUGH THE END OF THE WEEK IS EXPECTED. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MONDAY AND TUESDAY WITH DECREASING COVERAGE MID TO LATE WEEK. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 72 77 72 78 / 30 40 40 40 BROWNSVILLE 72 78 72 80 / 30 50 40 40 HARLINGEN 71 80 70 79 / 40 50 40 40 MCALLEN 72 80 71 79 / 30 50 40 40 RIO GRANDE CITY 71 80 68 78 / 30 40 50 60 SOUTH PADRE ISLAND 72 76 72 76 / 30 40 40 40 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 68/60
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1137 PM CDT SAT APR 18 2015 .DISCUSSION... SEE 06Z AVIATION DISCUSSION. && .AVIATION... A LINE OF SHRA/TSRA WILL MOVE ACROSS THE NORTHERN TAF SITES BEFORE 06Z AND A PERIOD OF LIGHT RAIN WILL LIKELY PERSIST THROUGH 08S IN THE WAKE OF THIS LINE. THINGS ARE A BIT MORE MUDDLED AS TO HOW FAR SOUTH THIS LINE OF PRECIP WILL MOVE. LATEST HRRR SHOWS AN EASTWARD PUSH TO THE NORTHERN HALF AND A SOUTHWARD PUSH TO THE WESTERN HALF OF THE LINE. THE LINE IS STILL GENERATING WIND GUSTS BETWEEN 30-40 KNOTS SO FEEL IT IS BEST TO CARRY VCTS AND TEMPO A WIND GUST GROUP AS FAR AS KHOU AND KSGR. THE COLD POOL/PRESSURE RISES LOOK STRONG ENOUGH TO SUPPORT THE HRRR SOLUTION FURTHER SOUTH. WINDS WILL LIKELY BECOME W-SW OVERNIGHT AND SW ON SUNDAY IN RESPONSE TO LOW PRESSURE MOVING EAST ALONG THE RED RIVER. THE HRRR/GFS ADVERTISE A TIGHT GRADIENT IN THE AFTN SO ADDED GUSTS TO THE NORTHERN TAF SITES CLOSER TO THE TIGHTER GRADIENT. A COLD FRONT WILL APPROACH SE TX ON SUN AFTN. NAM 12 FCST SOUNDINGS SHOW AN UNSTABLE ATMOSPHERE OVER THE NORTH. JET DYNAMICS LOOK FAVORABLE WITH SE TX LYING IN A LFQ BETWEEN 18-00Z. HAVE ADDED VCTS FOR KCXO NORTHWARD. SOUNDINGS NOT QUITE AS UNSTABLE FOR THE HOUSTON TERMINALS TOMORROW AFTN BUT THIS COULD CHANGE. ONE LAST CAVEAT...IF SKIES CLEAR TONIGHT...WOULD EXPECT FOG TO DEVELOP BUT JUST NOT SURE HOW MUCH CLEARING WILL OCCUR IN THE WAKE OF TONIGHTS STORMS. 43 && .PREV DISCUSSION... /ISSUED 857 PM CDT SAT APR 18 2015/ DISCUSSION... WATCHING A LINE OF STRONG/SEVERE STORMS HEADING TOWARD OUR WESTERN COUNTIES THIS EVENING. AT THIS TIME...SPC WAS NOT PLANNING ON ISSUING ANY WATCHES WITH THIS STORM COMPLEX. IF THE LATEST RUN OF THE HRRR IS CORRECT...EXPECT THESE STORMS TO WEAKEN AS THEY MOVE INTO AND ACROSS OUR AREA. 42 PREV DISCUSSION... /ISSUED 445 PM CDT SAT APR 18 2015/ DISCUSSION... SENT OUT AN UPDATED FORECAST PACKAGE AND RAISED POPS AREA WIDE DUE TO ONGOING/DEVELOPING CONVECTION ACROSS THE COASTAL COUNTIES AND OFF THE COAST...AND FOR DEVELOPING STORMS OUT WEST THAT THE MODELS HAVE MOVING INTO THE AREA THIS EVENING. SOME OF THE STORMS COULD HAVE THE POTENTIAL TO BECOME STRONG OR SEVERE...WITH DAMAGING WINDS... LARGE HAIL...AND LOCALLY HEAVY RAINFALL THE PRIMARY SEVERE WEATHER THREATS. 42 MARINE... AN UPPER LEVEL DISTURBANCE WILL GENERATE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE COASTAL WATERS THIS EVENING. SOME STORMS COULD BE STRONG. OTHERWISE...ONSHORE FLOW WILL PERSIST THROUGH SUNDAY. A COLD FRONT WILL PUSH OFF THE COAST SUNDAY NIGHT WITH MODERATE OFFSHORE WINDS IN ITS WAKE. WINDS WILL DIMINISH AND VEER BACK TO THE SOUTHEAST BY LATE TUESDAY NIGHT AS HIGH PRESSURE PUSHES OFF TO THE EAST. 47 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 63 85 56 75 54 / 60 20 10 10 20 HOUSTON (IAH) 64 85 61 78 57 / 50 20 20 10 10 GALVESTON (GLS) 69 81 66 77 66 / 50 20 20 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...42 AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
412 PM EDT SUN APR 19 2015 .SYNOPSIS... LOW PRESSURE OVER WESTERN KENTUCKY WITH A WARM FRONT EXTENDING EAST AND COLD FRONT TRAILING SOUTHWARD FROM THE LOW WILL LIFT NORTHEAST TONIGHT INTO MONDAY. A COLD FRONT CROSSES THE REGION ON MONDAY...THEN HIGH PRESSURE BUILDS IN FOR TUESDAY. && .NEAR TERM /THROUGH MONDAY/... AS OF 333 PM EDT SUNDAY... FLOOD WATCHES REMAIN IN EFFECT INTO TONIGHT. A WARM FRONT TO OUR SOUTH WILL LIFT NORTH THIS EVENING AND CROSS THE FORECAST AREA TONIGHT. DEEPER MOISTURE AND HIGHER PWATS WILL INCREASE IN THE WARM ADVECTION WITH THE NORTHWARD ADVANCE OF THE FRONT. THE REGIONAL RADAR IMAGE SHOWED WIDESPREAD CONVECTION ACROSS THE MID ATLANTIC REGION SOUTHWARD TO THE SOUTHEAST US. THERE ARE SOME CONCERNS OF STRONG CONVECTION ACROSS GEORGIA THIS AFTERNOON MAY TAKE SOME OF THE MOISTURE AWAY FROM OUR AREA. OUR LOCAL RNK WRFARW...HIRESW-ARW...NAM AND GFS WAIT UNTIL AFTER 00Z BEFORE BRINGING IN HEAVIER CONVECTION THIS EVENING...WHILE HRRR AND ECMWF ARE A LITTLE FASTER WITH TIMING. THE HRRR AND HIRESW-ARW LIFTS THE PRECIPITATION NORTHEAST WITH MOST OF RAIN PULLING OUT BY 06-08Z. USED A BLEND OF HRRR AND NAM FOR POPS...TAPERING POPS BACK AFTER 06Z TONIGHT INTO MONDAY MORNING. NOT EXPECTING ANY STRONG THUNDERSTORMS THIS AFTERNOON INTO TONIGHT WITH CLOUD COVER HINDERING INSTABILITIES. HOWEVER...THE LOW LEVEL JET INCREASING TO 50-60 KNOTS FROM THE SOUTHEAST WILL RESULT IN STRONG UPSLOPE AND ISENTROPIC LIFT. THE STRONG WINDS THROUGH A DEEP LAYER WILL PROVIDE LARGE HELICITY VALUES LATE THIS AFTERNOON INTO THIS EVENING. THE DAY ONE CONVECTIVE OUTLOOK (SWODY1) PLACED A MARGINAL (5 PERCENT CHANCE OF WIND) ACROSS SOUTHWEST PORTION OF CWA. PLAYED LOW TEMPERATURES CLOSE TO ADJMAV WITH READINGS FROM THE UPPER 40S IN THE NORTHWEST MOUNTAINS TO AROUND 60 DEGREES IN THE PIEDMONT. A WARM...MOIST AND UNSTABLE AIRMASS EXPECTED MONDAY. THE ATMOSPHERE WILL DESTABILIZE AHEAD OF THE APPROACHING COLD FRONT WITH SHOWERS AND THUNDERSTORMS DEVELOPING MONDAY. INITIALLY CUT BACK POPS CLOSER TO NAM FOR MONDAY MORNING...THEN INCREASED TO LIKELY BY MONDAY AFTERNOON. SPC CONTINUES OUR SLIGHT RISK FOR MONDAY ACROSS MOST OF OUR CWA. THIS IS SUPPORTED BY THE DYNAMIC ENVIRONMENT WITH HEALTHY SHEAR AND DECENT CAPES AROUND 2K. IT WILL ALSO BE QUITE BREEZY WITH EFFICIENT DOWNWARD MOMENTUM TRANSFER IN A WELL MIXED BOUNDARY LAYER. THE FRONT SHOULD BE CLEARING MONDAY NIGHT. HIGH TEMPERATURES MONDAY WILL RANGE FROM THE MID 60S IN THE MOUNTAINS TO THE LOWER 80S IN THE PIEDMONT. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... AS OF 345 PM EDT SUNDAY... TAIL END OF COLD FRONT AND ASSOCIATED CONVECTION WILL BE EXITING THE AREA JUST AFT 00Z. HOWEVER...A BROAD UPPER TROUGH...ALMOST WINTERLIKE PATTERN CONTINUES TO EVOLVE AND DEEPEN ACROSS THE GREAT LAKES WITH NUMEROUS SPOKES OF PVA/SHORT WAVES REMAINING UPSTREAM. THIS LEAVES THE REGION...ESPECIALLY THE MOUNTAINS...WITH A VERY UNSETTLED PATTERN. AT A MINIMUM...EXPECT VARIABLE CLOUDINESS. TIMING OF EMBEDDED DISTURBANCES WILL BE THE KEY TO THE TIMES FOR THE BETTER CHANCES OF SHOWERS. FOR SEVERAL DAYS...THE GFS HAS INSISTED ON A SIGNIFICANT DISTURBANCE MOVING THROUGH THE REGION WED WITH WIDESPREAD -SHRA AS A RESULT. THE OTHER MODELS REMAIN LACKLUSTER WITH THIS FEATURE...BUT DO SUGGEST AT LEAST SOME SMALL CHANCE WITHIN THIS TIME FRAME. GIVEN THE UNSETTLED NATURE OF THE PATTERN WITH UPSLOPE FLOW AND VERY DIFFICULT TO TIME UPPER DISTURBANCES...CANNOT REALLY DROP POPS AT ANY TIME. BEST FOCUS THROUGH THE PERIOD WILL REMAIN WEST OF THE BLUE RIDGE...AND ESPECIALLY ACROSS THE MOUNTAINS OF WV/FAR SW VA. IN ADDITION...ENOUGH INSTABILITY SUGGESTED WITH COLD AIR ALOFT...TO INTRODUCE ISOLD TSRA WITH THE WED DISTURBANCE AS WELL. 850MB TEMPS DROP TO NEAR 0C ACROSS THE NORTHERN PART OF THE FORECAST AREA BY WED...BUT THE BETTER COLD ADVECTION COMES IN THE EXTENDED PERIOD BEHIND THE WED DISTURBANCE. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AS OF 400 PM EDT SUNDAY... BROAD UPPER TROUGH REMAINS IN PLACE AND DOMINATES THE EXTENDED FORECAST...GRADUALLY SHIFTING FURTHER ESE LATE IN THE PERIOD. THIS KEEPS THE REGION IN AN UNSTABLE/UNSETTLED NORTHWEST FLOW WITH NUMEROUS EMBEDDED SHORT WAVES. MODELS VARY CONSIDERABLY AS TO THE TIMING AND PLACEMENT OF THESE DISTURBANCES...BUT ENOUGH AGREEMENT THAT POPS CANNOT BE DROPPED REALLY AT ANY TIME THE OVERALL TREND IS TO PUSH THE BETTER MOISTURE FURTHER SOUTH OF THE REGION AS THE WEEK PROGRESSES AND 850MB TEMPS DROP BELOW 0C IN THE NORTHERN COUNTIES. THE ENTIRE PERIOD SHOULD FEATURE BELOW NORMAL TEMPERATURES WITH LOW CHC POPS...HIGHEST ACROSS THE MOUNTAINS AND TOWARD THE SOUTHERN COUNTIES...WITH THE NORTHERN PIEDMONT THE DRIEST. ALTHOUGH TEMPERATURES WILL BE BELOW NORMAL THROUGHOUT THE PERIOD...NO REAL CLEAR CONCERN AT THIS POINT FOR FROST/FREEZE BECAUSE OF CYCLONIC FLOW AND CLOUDS. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... AS OF 142 PM EDT SUNDAY... KFCX WSR-88D SHOWED RAIN SPREADING NORTHEAST ACROSS THE FORECAST AREA THIS AFTERNOON...AS A WARM FRONT LIFTS NORTH ACROSS THE REGION. CEILINGS WILL LOWER TO MVFR AND IFR WITH RAIN. A STRONG SOUTHEAST LOW LEVEL JET WILL CONTINUE TO INCREASE THIS AFTERNOON AND TONIGHT WHICH WILL BRING WIND GUSTS AS HIGH AS 30 KTS. WITH A WEDGE OF HIGH PRESSURE IN PLACE ALONG AND EAST OF THE BLUE RIDGE...AFTER SUNSET THESE STRONG WINDS ARE NOT EXPECTED TO REACH THE SURFACE. SHORTEN THE TIME WINDOW AND KEPT LLWS IN THE KLWB AND KBCB TAFS AFTER 00Z/8PM. CEILINGS WILL LOWER TO IFR THIS EVENING INTO TONIGHT AND WILL REMAIN LOW OVERNIGHT. A COLD FRONT APPROACHES LATER MONDAY WITH SOME THUNDERSTORMS POSSIBLE AHEAD OF AND ALONG THE FRONT...ESPECIALLY EAST OF THE BLUE RIDGE. THIS IS LIKELY TO KEEP PERIODS OF MVFR AND BRIEF IFR IN STORMS UNTIL THE FRONT CLEARS THE REGION MONDAY EVENING. MEDIUM CONFIDENCE IN CEILINGS...VISIBILITIES AND WINDS DURING THE TAF PERIOD. EXTENDED AVIATION... VFR RETURNS LATER MONDAY NIGHT AND TUESDAY WITH HIGH PRESSURE BUILDING IN BEHIND THE FRONT WITH A DRIER AIRMASS. THEN THE NEXT CHANCE OF MVFR CONDITIONS AND PRECIPITATION WILL BE IN THE MOUNTAINS ON WEDNESDAY AND THURSDAY. && .HYDROLOGY... AS OF 330 PM EDT SUNDAY... HAVE EXPANDED THE FLOOD WATCH FOR THE ALLEGHANY HIGHLANDS OF VIRGINIA. A DEEP LAYER FROM THE SURFACE THROUGH MID LEVELS OF THE ATMOSPHERE OF SOUTHEAST WINDS...WILL BE INCREASING TO AROUND 50 KNOTS LATER THIS AFTERNOON AND EVENING. PRECIPITABLE WATER VALUES JUST ABOVE 1.5 INCHES WILL BE ADVECTED INTO THE FORECAST AREA. THE STRONGEST LIFT AND HIGHEST RAINFALL AMOUNTS WILL BE FROM 18Z/2PM THROUGH 06Z/2AM SO HAVE ADDED HEAVY RAIN TO THE FORECAST ALONG THE BLUE RIDGE FOR THIS TIME FRAME. TOTAL RAINFALL AMOUNTS WILL RANGE FROM 1 TO 3 INCHES THROUGH 12Z/8AM MONDAY. FLASH FLOOD GUIDANCE VALUES WERE ROUGHLY 1.5 TO 2.5 INCHES FOR 3 HOURS. SO THIS AMOUNT OF RAINFALL HAS THE POTENTIAL TO PRODUCE FLOODING ON SMALL STREAMS AND CREEKS. PROBABILISTIC GUIDANCE FOR MAINSTEM RIVERS SUGGESTS A SMALL POSSIBILITY FOR MINOR FLOODING ALONG THE DAN RIVER AND NEW RIVER. HOWEVER...THE IS HIGHLY DEPENDENT ON THE AMOUNT OF RAINFALL THROUGH MONDAY MORNING. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ018>020-022>024- 033>035. FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR VAZ009-012>017-032. NC...FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR NCZ001>003-018>020. WV...NONE. && $$ SYNOPSIS...AMS/KK NEAR TERM...KK SHORT TERM...RAB LONG TERM...RAB AVIATION...AMS/KK HYDROLOGY...KK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
334 PM EDT SUN APR 19 2015 .SYNOPSIS... LOW PRESSURE OVER WESTERN KENTUCKY WITH A WARM FRONT EXTENDING EAST AND COLD FRONT TRAILING SOUTHWARD FROM THE LOW WILL LIFT NORTHEAST TONIGHT INTO MONDAY. A COLD FRONT CROSSES THE REGION ON MONDAY...THEN HIGH PRESSURE BUILDS IN FOR TUESDAY. && .NEAR TERM /THROUGH MONDAY/... AS OF 333 PM EDT SUNDAY... FLOOD WATCHES REMAIN IN EFFECT INTO TONIGHT. A WARM FRONT TO OUR SOUTH WILL LIFT NORTH THIS EVENING AND CROSS THE FORECAST AREA TONIGHT. DEEPER MOISTURE AND HIGHER PWATS WILL INCREASE IN THE WARM ADVECTION WITH THE NORTHWARD ADVANCE OF THE FRONT. THE REGIONAL RADAR IMAGE SHOWED WIDESPREAD CONVECTION ACROSS THE MID ATLANTIC REGION SOUTHWARD TO THE SOUTHEAST US. THERE ARE SOME CONCERNS OF STRONG CONVECTION ACROSS GEORGIA THIS AFTERNOON MAY TAKE SOME OF THE MOISTURE AWAY FROM OUR AREA. OUR LOCAL RNK WRFARW...HIRESW-ARW...NAM AND GFS WAIT UNTIL AFTER 00Z BEFORE BRINGING IN HEAVIER CONVECTION THIS EVENING...WHILE HRRR AND ECMWF ARE A LITTLE FASTER WITH TIMING. THE HRRR AND HIRESW-ARW LIFTS THE PRECIPITATION NORTHEAST WITH MOST OF RAIN PULLING OUT BY 06-08Z. USED A BLEND OF HRRR AND NAM FOR POPS...TAPERING POPS BACK AFTER 06Z TONIGHT INTO MONDAY MORNING. NOT EXPECTING ANY STRONG THUNDERSTORMS THIS AFTERNOON INTO TONIGHT WITH CLOUD COVER HINDERING INSTABILITIES. HOWEVER...THE LOW LEVEL JET INCREASING TO 50-60 KNOTS FROM THE SOUTHEAST WILL RESULT IN STRONG UPSLOPE AND ISENTROPIC LIFT. THE STRONG WINDS THROUGH A DEEP LAYER WILL PROVIDE LARGE HELICITY VALUES LATE THIS AFTERNOON INTO THIS EVENING. THE DAY ONE CONVECTIVE OUTLOOK (SWODY1) PLACED A MARGINAL (5 PERCENT CHANCE OF WIND) ACROSS SOUTHWEST PORTION OF CWA. PLAYED LOW TEMPERATURES CLOSE TO ADJMAV WITH READINGS FROM THE UPPER 40S IN THE NORTHWEST MOUNTAINS TO AROUND 60 DEGREES IN THE PIEDMONT. A WARM...MOIST AND UNSTABLE AIRMASS EXPECTED MONDAY. THE ATMOSPHERE WILL DESTABILIZE AHEAD OF THE APPROACHING COLD FRONT WITH SHOWERS AND THUNDERSTORMS DEVELOPING MONDAY. INITIALLY CUT BACK POPS CLOSER TO NAM FOR MONDAY MORNING...THEN INCREASED TO LIKELY BY MONDAY AFTERNOON. SPC CONTINUES OUR SLIGHT RISK FOR MONDAY ACROSS MOST OF OUR CWA. THIS IS SUPPORTED BY THE DYNAMIC ENVIRONMENT WITH HEALTHY SHEAR AND DECENT CAPES AROUND 2K. IT WILL ALSO BE QUITE BREEZY WITH EFFICIENT DOWNWARD MOMENTUM TRANSFER IN A WELL MIXED BOUNDARY LAYER. THE FRONT SHOULD BE CLEARING MONDAY NIGHT. HIGH TEMPERATURES MONDAY WILL RANGE FROM THE MID 60S IN THE MOUNTAINS TO THE LOWER 80S IN THE PIEDMONT. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... AS OF 345 AM EDT SUNDAY... COLDER AIR WORKING IN ON NW WINDS BEHIND THE FRONT WILL COMBINE WITH LOW LEVEL MOISTURE TO GENERATE SOME UPSLOPE SHOWERS ACROSS THE FAR WESTERN SLOPES MONDAY NIGHT. A BROAD CLOSED UPPER LOW BUILDING IN OVER THE NORTHEAST US WILL THEN KEEP COOL...BREEZY...AND UNSETTLED WEATHER CONDITIONS ACROSS THE REGION THROUGH MIDWEEK. TUESDAY LOOKS TO BE THE BEST CHANCE FOR A BREAK IN THE ACTION AS ANY LINGERING SHOWERS ACROSS THE FAR WEST DISSIPATE BY EARLY MORNING. BY WEDNESDAY THE NEXT COLD FRONT WILL BE ROTATING IN FROM THE WEST WITH A CHANCE FOR SHOWERS AND MAYBE SOME THUNDER ESPECIALLY WEST OF THE BLUE RIDGE. TEMPERATURES TUESDAY AND WEDNESDAY WILL BE RUNNING AT OR SLIGHTLY BELOW NORMAL WITH UPPER 50S/LOWER 60S WEST OF THE BLUE RIDGE AND MID 60S TO AROUND 70 EAST. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AS OF 350 PM EDT SATURDAY... MODELS IN BETTER AGREEMENT TODAY ON A DEEP AND BROAD UPPER LOW CENTERED ACROSS THE EASTERN GREAT LAKES DOMINATING THE WEATHER THROUGH MOST OF THE REMAINDER OF THE WORK WEEK. THIS WILL LEAVE UNSETTLED CONDITIONS ACROSS THE MOUNTAINS...SOMEWHAT LESS SO ACROSS THE PIEDMONT. FOLLOWING THIS DISTURBANCE COMES THE BONAFIDE COLDER AIR WHICH PROMISES TO PUSH 850MB TEMPS DOWN TO 0C OR BELOW FOR MUCH OF THE REMAINDER OF THE WEEK ACROSS THE NORTHERN AREAS. THE UPPER TROUGH GRADUALLY SHIFTS MORE TOWARD THE MID-ATLANTIC LATE IN THE PERIOD...STRENGTHENING THE NORTHWEST FLOW ACROSS THE REGION...AND ALLOWING 850MB TEMPS TO BOTTOM OUT ACROSS THE NORTH AROUND -5C BY SATURDAY. THIS PATTERN WILL CONTINUE TO RESULT IN A SIGNIFICANT TEMPERATURE DIFFERENCE FROM THE WESTERN MOUNTAINS WITH CLOUDS AND VARIABLE CLOUDS/SCATTERED SHOWERS AND MORE SUNNY/DOWNSLOPE NORTHWEST FLOW ACROSS THE PIEDMONT. OVERALL...TEMPERATURES SHOULD AVERAGE BELOW NORMAL THROUGH THE PERIOD...PERHAPS MUCH BELOW IN THE WEST. MEXMOS SHOWS SEVERAL DAYS WITH HIGHS ONLY IN THE 50S/60S WEST AND LOWS IN THE UPPER 30S TO LOWER 40S. WIND AND CLOUDS SHOULD PREVENT ANY FROST/FREEZE CONCERN AT THIS POINT. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... AS OF 142 PM EDT SUNDAY... KFCX WSR-88D SHOWED RAIN SPREADING NORTHEAST ACROSS THE FORECAST AREA THIS AFTERNOON...AS A WARM FRONT LIFTS NORTH ACROSS THE REGION. CEILINGS WILL LOWER TO MVFR AND IFR WITH RAIN. A STRONG SOUTHEAST LOW LEVEL JET WILL CONTINUE TO INCREASE THIS AFTERNOON AND TONIGHT WHICH WILL BRING WIND GUSTS AS HIGH AS 30 KTS. WITH A WEDGE OF HIGH PRESSURE IN PLACE ALONG AND EAST OF THE BLUE RIDGE...AFTER SUNSET THESE STRONG WINDS ARE NOT EXPECTED TO REACH THE SURFACE. SHORTEN THE TIME WINDOW AND KEPT LLWS IN THE KLWB AND KBCB TAFS AFTER 00Z/8PM. CEILINGS WILL LOWER TO IFR THIS EVENING INTO TONIGHT AND WILL REMAIN LOW OVERNIGHT. A COLD FRONT APPROACHES LATER MONDAY WITH SOME THUNDERSTORMS POSSIBLE AHEAD OF AND ALONG THE FRONT...ESPECIALLY EAST OF THE BLUE RIDGE. THIS IS LIKELY TO KEEP PERIODS OF MVFR AND BRIEF IFR IN STORMS UNTIL THE FRONT CLEARS THE REGION MONDAY EVENING. MEDIUM CONFIDENCE IN CEILINGS...VISIBILITIES AND WINDS DURING THE TAF PERIOD. EXTENDED AVIATION... VFR RETURNS LATER MONDAY NIGHT AND TUESDAY WITH HIGH PRESSURE BUILDING IN BEHIND THE FRONT WITH A DRIER AIRMASS. THEN THE NEXT CHANCE OF MVFR CONDITIONS AND PRECIPITATION WILL BE IN THE MOUNTAINS ON WEDNESDAY AND THURSDAY. && .HYDROLOGY... AS OF 330 PM EDT SUNDAY... HAVE EXPANDED THE FLOOD WATCH FOR THE ALLEGHANY HIGHLANDS OF VIRGINIA. A DEEP LAYER FROM THE SURFACE THROUGH MID LEVELS OF THE ATMOSPHERE OF SOUTHEAST WINDS...WILL BE INCREASING TO AROUND 50 KNOTS LATER THIS AFTERNOON AND EVENING. PRECIPITABLE WATER VALUES JUST ABOVE 1.5 INCHES WILL BE ADVECTED INTO THE FORECAST AREA. THE STRONGEST LIFT AND HIGHEST RAINFALL AMOUNTS WILL BE FROM 18Z/2PM THROUGH 06Z/2AM SO HAVE ADDED HEAVY RAIN TO THE FORECAST ALONG THE BLUE RIDGE FOR THIS TIME FRAME. TOTAL RAINFALL AMOUNTS WILL RANGE FROM 1 TO 3 INCHES THROUGH 12Z/8AM MONDAY. FLASH FLOOD GUIDANCE VALUES WERE ROUGHLY 1.5 TO 2.5 INCHES FOR 3 HOURS. SO THIS AMOUNT OF RAINFALL HAS THE POTENTIAL TO PRODUCE FLOODING ON SMALL STREAMS AND CREEKS. PROBABILISTIC GUIDANCE FOR MAINSTEM RIVERS SUGGESTS A SMALL POSSIBILITY FOR MINOR FLOODING ALONG THE DAN RIVER AND NEW RIVER. HOWEVER...THE IS HIGHLY DEPENDENT ON THE AMOUNT OF RAINFALL THROUGH MONDAY MORNING. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ018>020-022>024- 033>035. FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR VAZ009-012>017-032. NC...FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR NCZ001>003-018>020. WV...NONE. && $$ SYNOPSIS...AMS/KK NEAR TERM...KK SHORT TERM...MBS LONG TERM...RAB AVIATION...AMS/KK HYDROLOGY...AMS/KK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
959 AM EDT SUN APR 19 2015 .SYNOPSIS... HIGH PRESSURE WAS OVER SOUTHEAST CANADA AND LOW PRESSURE WAS IN ARKANSAS WITH A WARM FROM EXTENDING INTO SOUTH CAROLINA. THE LOW AND WARM FRONT WILL MOVE NORTH TODAY AND TONIGHT. A COLD FRONT CROSSES THE REGION ON MONDAY THEN HIGH PRESSURE BUILDS IN FOR TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 958 AM EDT SUNDAY... FLOOD WATCHES REMAIN IN EFFECT FROM THIS AFTERNOON INTO TONIGHT. A WARM FRONT WILL LIFT NORTH TODAY AND CROSS THE FORECAST AREA TONIGHT. DEEPER MOISTURE AND HIGHER PWATS WILL INCREASE IN THE WARM ADVECTION WITH THE NORTHWARD ADVANCE OF THE FRONT. THE RNK WRF-ARW...HIRESW-ARW AND HRRR SHOWED WIDESPREAD RAIN LIFTING NORTHWARD ACROSS OUR AREA. LOW LEVEL JET INCREASING TO 50-60 KNOTS FROM THE SOUTHEAST WILL RESULT IN STRONG UPSLOPE AND ISENTROPIC LIFT. THE STRONG WINDS THROUGH A DEEP LAYER WILL PROVIDE LARGE HELICITY VALUES LATE THIS AFTERNOON INTO THIS EVENING. THE DAY ONE CONVECTIVE OUTLOOK (SWODY1) PLACED A MARGINAL (5 PERCENT CHANCE OF WIND) ACROSS SOUTHWEST PORTION OF CWA. MODIFIED TEMPERATURES...DEW POINT AND POPS FR THIS MORNING INTO THIS AFTERNOON. MORE ADJUSTMENTS AS THE DAY PROGRESSES... AS OF 430 AM EDT SUNDAY... WARM FRONT ASSOCIATED WITH A LOW IN ARKANSAS WILL MOVE NORTH TODAY AND WILL CROSS THROUGH THE FORECAST AREA TONIGHT. STRONG SYNOPTIC SCALE LIFT WILL PRODUCE WIDESPREAD RAIN ACROSS THE FORECAST AREA. LOW LEVEL JET INCREASING TO 50-60 KNOTS FROM THE SOUTHEAST WILL RESULT IN STRONG UPSLOPE AND ISENTROPIC LIFT. RAIN WILL SPREAD INTO THE AREA FROM SOUTHWEST TO NORTHEAST BEFORE 18Z/2PM. MOST LOCATIONS WILL HAVE ABOUT A 12 HOUR PERIOD OF LIGHT TO MODERATE RAIN. HAVE PRECIPITATION ENDING FROM SOUTHWEST TO NORTHEAST AFTER 06Z/2AM. TEMPERATURES STARTING THE DAY QUITE MILD. GRIDDED LAMP GUIDANCE INDICATED STEADY AND POSSIBLY SLIGHTLY FALLING TEMPERATURES TODAY. LITTLE CHANGE IN AIR MASS IS EXPECTED TONIGHT WITH TEMPERATURES AND DEW POINTS REMAINING MAINLY IN THE 50S. THE STRONG WINDS THROUGH A DEEP LAYER WILL PROVIDE LARGE HELICITY VALUES LATE THIS AFTERNOON INTO THIS EVENING. THERE IS A LOW CHANCE THERE COULD BE ENHANCED DIRECTIONAL SHEAR AS THE WARM FRONT CROSSES. FOR NOW WILL LEAVE OUT ANY THUNDER. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... AS OF 345 AM EDT SUNDAY... THE NEW WEEK STARTS OFF WITH OUR REGION IN A WARM AND MOIST AIRMASS. AS TEMPERATURES RISE WELL INTO THE 70S ON MONDAY THE ATMOSPHERE WILL DESTABILIZE AHEAD OF THE APPROACHING COLD FRONT AND THUNDERSTORMS ARE EXPECTED TO DEVELOP. THE DYNAMIC ENVIRONMENT SUPPORTS THE CHANCE FOR SOME SEVERE STORMS AND THE SPC SLIGHT RISK LOOKS TO BE ON TARGET ACROSS OUR AREA WITH THE POTENTIAL FOR SVR WEATHER INCREASING EASTWARD WHERE INSTABILITY WILL BE GREATER. IT WILL ALSO BE QUITE BREEZY WITH EFFICIENT DOWNWARD MOMENTUM TRANSFER IN A WELL MIXED BOUNDARY LAYER. THE FRONT SHOULD BE CLEARING THE EASTERN ZONES EARLY MONDAY EVENING. COLDER AIR WORKING IN ON NW WINDS BEHIND THE FRONT WILL COMBINE WITH LOW LEVEL MOISTURE TO GENERATE SOME UPSLOPE SHOWERS ACROSS THE FAR WESTERN SLOPES MONDAY NIGHT. A BROAD CLOSED UPPER LOW BUILDING IN OVER THE NORTHEAST US WILL THEN KEEP COOL...BREEZY...AND UNSETTLED WEATHER CONDITIONS ACROSS THE REGION THROUGH MIDWEEK. TUESDAY LOOKS TO BE THE BEST CHANCE FOR A BREAK IN THE ACTION AS ANY LINGERING SHOWERS ACROSS THE FAR WEST DISSIPATE BY EARLY MORNING. BY WEDNESDAY THE NEXT COLD FRONT WILL BE ROTATING IN FROM THE WEST WITH A CHANCE FOR SHOWERS AND MAYBE SOME THUNDER ESPECIALLY WEST OF THE BLUE RIDGE. TEMPERATURES TUESDAY AND WEDNESDAY WILL BE RUNNING AT OR SLIGHTLY BELOW NORMAL WITH UPPER 50S/LOWER 60S WEST OF THE BLUE RIDGE AND MID 60S TO AROUND 70 EAST. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... AS OF 350 PM EDT SATURDAY... MODELS IN BETTER AGREEMENT TODAY ON A DEEP AND BROAD UPPER LOW CENTERED ACROSS THE EASTERN GREAT LAKES DOMINATING THE WEATHER THROUGH MOST OF THE REMAINDER OF THE WORK WEEK. THIS WILL LEAVE UNSETTLED CONDITIONS ACROSS THE MOUNTAINS...SOMEWHAT LESS SO ACROSS THE PIEDMONT. FOLLOWING THIS DISTURBANCE COMES THE BONAFIDE COLDER AIR WHICH PROMISES TO PUSH 850MB TEMPS DOWN TO 0C OR BELOW FOR MUCH OF THE REMAINDER OF THE WEEK ACROSS THE NORTHERN AREAS. THE UPPER TROUGH GRADUALLY SHIFTS MORE TOWARD THE MID-ATLANTIC LATE IN THE PERIOD...STRENGTHENING THE NORTHWEST FLOW ACROSS THE REGION...AND ALLOWING 850MB TEMPS TO BOTTOM OUT ACROSS THE NORTH AROUND -5C BY SATURDAY. THIS PATTERN WILL CONTINUE TO RESULT IN A SIGNIFICANT TEMPERATURE DIFFERENCE FROM THE WESTERN MOUNTAINS WITH CLOUDS AND VARIABLE CLOUDS/SCATTERED SHOWERS AND MORE SUNNY/DOWNSLOPE NORTHWEST FLOW ACROSS THE PIEDMONT. OVERALL...TEMPERATURES SHOULD AVERAGE BELOW NORMAL THROUGH THE PERIOD...PERHAPS MUCH BELOW IN THE WEST. MEXMOS SHOWS SEVERAL DAYS WITH HIGHS ONLY IN THE 50S/60S WEST AND LOWS IN THE UPPER 30S TO LOWER 40S. WIND AND CLOUDS SHOULD PREVENT ANY FROST/FREEZE CONCERN AT THIS POINT. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... AS OF 745 AM EDT SUNDAY... RAIN HAD ADVANCED INTO SOUTHWEST VIRGINIA AND WESTERN NORTH CAROLINA THIS MORNING WITH CEILINGS LOWERING IN ADVANCE OF THE RAIN. RAIN WILL BEGIN AT KBLF AROUND THE 12Z START OF THE TAF TIME AND BY 16Z/NOON AT THE OTHER TAF SITES. A STRONG SOUTHEAST LOW LEVEL JET WILL CONTINUE TO INCREASE TODAY AND TONIGHT WHICH WILL BRING WIND GUSTS AS HIGH AS 30 KTS TODAY. WITH A WEDGE OF HIGH PRESSURE IN PLACE ALONG AND EAST OF THE BLUE RIDGE...AFTER SUNSET THESE STRONG WINDS ARE NOT EXPECTED TO REACH THE SURFACE. HAVE LLWS IN THE KDAN...KLWB AND KBCB TAFS AFTER 00Z/8PM. A STRONG UPSLOPE FLOW WILL TRANSPORT ABUNDANT MOISTURE INTO THE REGION NORTH OF A STATIONARY FRONT TODAY. CEILINGS WILL LOWER TO IFR BY THIS AFTERNOON AND WILL REMAIN LOW OVERNIGHT. EXTENDED AVIATION... A COLD FRONT APPROACHES LATER MONDAY WITH SOME STORMS POSSIBLE AHEAD OF AND ALONG THE FRONT...ESPECIALLY EAST OF THE BLUE RIDGE. THIS IS LIKELY TO KEEP PERIODS OF MVFR AND BRIEF IFR IN STORMS UNTIL THE FRONT CLEARS THE REGION MONDAY EVENING. VFR RETURNS LATER MONDAY NIGHT AND TUESDAY WITH HIGH PRESSURE BUILDING IN BEHIND THE FRONT WITH A DRIER AIRMASS. THEN THE NEXT CHANCE OF MVFR CONDITIONS AND PRECIPITATION WILL BE IN THE MOUNTAINS ON WEDNESDAY AND THURSDAY. && .HYDROLOGY... AS OF 430 AM EDT SUNDAY... HAVE EXPANDED THE FLOOD WATCH FOR MORE OF THE SOUTHERN BLUE RIDGE AND FOR THE BLUE RIDGE AND ADJACENT EASTERN COUNTIES NORTH OF OF ROANOKE. BUFKIT SOUNDINGS SHOWED A DEEP LAYER FROM THE SURFACE THROUGH MID LEVELS OF THE ATMOSPHERE WITH SOUTHEAST WINDS...THAT WILL BE INCREASING TO AROUND 50 KNOTS THIS AFTERNOON AND EVENING. PRECIPITABLE WATER VALUES JUST ABOVE 1.5 INCHES WILL BE ADVECTED INTO THE FORECAST AREA. THE STRONGEST LIFT AND HIGHEST RAINFALL AMOUNTS WILL BE FROM 18Z/2PM THROUGH 06Z/2AM SO HAVE ADDED HEAVY RAIN TO THE FORECAST ALONG THE BLUE RIDGE FOR THIS TIME FRAME. TOTAL RAINFALL AMOUNTS WILL RANGE FROM 1 TO 3 INCHES THROUGH 12Z/8AM MONDAY. FLASH FLOOD GUIDANCE VALUES WERE ROUGHLY 1.5 TO 2.5 INCHES FOR 3 HOURS. SO THIS AMOUNT OF RAINFALL HAS THE POTENTIAL TO PRODUCE FLOODING ON SMALL STREAMS AND CREEKS. PROBABILISTIC GUIDANCE FOR MAINSTEM RIVERS SUGGESTS A SMALL POSSIBILITY FOR MINOR FLOODING ALONG THE DAN RIVER AND NEW RIVER. HOWEVER...THE IS HIGHLY DEPENDENT ON THE AMOUNT OF RAINFALL THROUGH MONDAY MORNING. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...FLOOD WATCH THROUGH THIS EVENING FOR VAZ009-012>017-032. FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH LATE TONIGHT FOR VAZ022>024-033>035. NC...FLOOD WATCH THROUGH THIS EVENING FOR NCZ001>003-018>020. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS/KK SHORT TERM...MBS LONG TERM...RAB AVIATION...AMS/PC HYDROLOGY...AMS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
147 AM EDT SUN APR 19 2015 .SYNOPSIS... HIGH PRESSURE WILL DRIFT EAST TONIGHT ALLOWING CLOUDS FROM LOW PRESSURE OVER THE TENNESSEE VALLEY TO SPREAD ACROSS THE REGION OVERNIGHT. RAIN...HEAVY AT TIMES...WILL FALL SUNDAY INTO SUNDAY NIGHT BEFORE A COLD FRONT CROSSES THE REGION WITH A CHANCE OF SHOWERS AND POTENTIALLY STRONG STORMS ON MONDAY. DRY AND COOL CONDITIONS WILL PREVAIL FOR THE MIDDLE PART OF NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... AS OF 912 PM EDT SATURDAY STILL A FEW DIURNAL SHOWERS ALONG THE BLUE RIDGE BUT THEY ARE FADING FAST. WILL REMOVE POPS FOR THE REST OF THE EVENING...THEN INCREASE POPS TOWARDS SUNRISE AS LOW PRESSURE ENTERS THE TENNESSEE VALLEY. MINOR UPDATES TO OTHER GRIDS. PREVIOUS DISCUSSION... AS OF 300 PM EDT SATURDAY WEAK LOW LEVEL CONVERGENCE JUST SOUTH OF OUR FORECAST AREA HAS IGNITED A FEW SHOWERS AND ISOLATED STORMS. THE HRRR MODEL LIFTS THIS BOUNDARY SLIGHTLY NORTH. THIS COMBINED WITH A WEAK UPSLOPE FLOW MAY FIRE A FEW SHOWERS AND ISOLATED STORMS SOUTH OF HIGHWAY 58 THIS AFTERNOON AND EARLY THIS EVENING...THEREFORE KEPT A SMALL CHANCE FOR POPS IN THE FORECAST. ALL THE MODELS ARE IN GOOD AGREEMENT ON DEVELOPING A STRONG LOW LEVEL SOUTHEAST JET...TRANSPORTING MOISTURE INTO THE AREA OVERNIGHT. A FEW GUSTS OVER 30KTS WILL BE POSSIBLE IN SOUTHEAST WV/CLINCH RIVER VALLEY VA OVERNIGHT AND SUNDAY...BUT VALUES ARE BELOW GUIDANCE CRITERIA. PWATS INCREASE TO 2-3 STANDARD DEVIATIONS ABOVE AVERAGE BY SUNDAY MORNING AND THROUGH MUCH OF THE DAY SUNDAY. MEANWHILE...A LARGE AREA UVV LIFTS NORTH INTO OUR REGION TOWARD DAWN THEN EAST OVER ENTIRE AREA ON SUNDAY. THIS IS IN ADVANCE OF A NEGATIVELY TILTED UPPER TROF LIFTING THROUGH THE OHIO VALLEY SUNDAY WHICH ALSO GENERATES STRONG UPPER DIFFLUENCE. AS A RESULT...EXPECT MODERATE TO HEAVY RAIN TO FALL FOR SEVERAL HOURS...ESPECIALLY ALONG THE EAST SLOPES OF THE BLUE RIDGE. MORE INFORMATION ABOUT THE FLOODING POTENTIAL FROM THIS SYSTEM CAN BE FOUND IN THE HYDROLOGY SECTION. BOTTOM LINE...A FLOOD WATCH WILL BE POSTED FOR THE NW NC MOUNTAINS/FOOTHILLS AND SOUTHERN BLUE RIDGE OF VA. FUTURE SHIFTS MAY NEED TO EXPAND THIS NORTH AND EAST...IF HIGHER QPF TRENDS CONTINUE. CONTINUED TO GO BELOW GUIDANCE FOR HIGHS SUNDAY...WITH WEDGE IN PLACE AND WIDESPREAD CLOUDS AND PRECIPITATION. IN FACT...MANY AREAS IN THE WEDGE LIKELY SEE LITTLE...IF ANY...RECOVERY IN TEMPS. && .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... AS OF 335 PM EDT SATURDAY... HEAVIER RAINFALL ASSOCIATED WITH NORTHEASTWARD MOVING STRONGLY NEGATIVELY TILTED UPPER TROUGH AND ASSOCIATED WARM/WEDGE FRONT WILL MOVE INTO THE PIEDMONT THROUGH 06Z MON...THEN EAST OF THE CWA BETWEEN 06Z AND 12Z MON. ADDITIONAL RAINFALL OF 1/2 TO 3/4 INCH DURING THIS TIME FRAME SHOULD BE CONFINED TO THE PIEDMONT. FLOOD WATCH ENDS AT 04Z MON...WHICH SHOULD BE GOOD TIMING. MEANWHILE...A BROAD UPPER TROUGH CONTINUES TO DEEPEN ACROSS THE GREAT LAKES WITH UPPER FLOW REMAINING SOUTHWEST BEHIND THE AFOREMENTIONED UPPER TROUGH. THE NEXT UPPER SHORT WAVE WILL BE APPROACHING THE WESTERN AREAS BY DAYBREAK MONDAY WITH A STRONG COLD FRONT MOVING INTO THE WESTERN TN/OH VALLEY. SCATTERED SHOWERS SHOULD DEVELOP ONCE AGAIN ACROSS THE WESTERN MOUNTAINS IN ADVANCE OF THESE FEATURES. BY AFTERNOON...MUCH OF THE CWA...ESPECIALLY EAST OF THE BLUE RIDGE WILL BE SOLIDLY IN THE WARM SECTOR WITH TEMPERATURES ACROSS THE PIEDMONT NEAR 80 DEGREES AND DEWPOINTS NEAR 60. A 6-HOUR WINDOW OF SUBSTANTIAL CAPE IN EXCESS OF 1000 J/KG...BULK 0-6KM SHEAR OF 20-30KTS...LIS TO -6 ALONG THE VA/NC BORDER...AND SIG SVR PARMS GREATER THAN 20000 COMBINED WITH STRONG PVA AND YET ANOTHER NEGATIVELY TILTED SHORT WAVE STRONGLY SUPPORT THE SLIGHT RISK OUTLOOK FROM SPC EAST OF THE BLUE RIDGE MON AFTERNOON...WITH THE MARGINAL RISK FURTHER WEST INTO THE MOUNTAINS. MAIN CONCERNS WILL BE THUNDERSTORM WIND GUSTS AND HAIL WITH COLD AIR ALOFT ADVECTING INTO THE REGION. A FEW MORE DISCRETE CELLS COULD DEVELOP EAST OF THE FRONT ACROSS THE PIEDMONT IF MAXIMUM INSTABILITY/HEATING IS REALIZED. THE SEVERE THREAT WILL END QUICKLY FROM WEST TO EAST AFT 00Z AS THE THERMODYNAMICS WANE QUICKLY AND THE UPPER SUPPORT SHIFTS NORTHEAST OF THE REGION. RAINFALL WILL NOT BE A CONCERN WITH THIS SECOND EVENT AS ACTIVITY WILL BE BRIEF AND SCATTERED...BUT A QUICK 1/2 INCH OF RAIN MAY OCCUR IN AREAS WITH HEAVIER SHOWERS/THUNDERSTORMS. SCATTERED UPSLOPE RAIN SHOWERS COULD PERSIST ACROSS THE MOUNTAINS INTO TUESDAY...BUT NO SIGNIFICANT DYNAMICS ARE FORESEEN WITHIN THIS TIME FRAME. UNSEASONABLY WARM TEMPERATURES MONDAY WILL GIVE WAY TO MUCH COOLER CONDITIONS ACROSS THE MOUNTAINS TUESDAY WITH VARIABLE CLOUDS AND A FEW SHOWERS...BUT DOWNSLOPE PIEDMONT AREAS SHOULD STILL BE CLOSE TO 70 EVEN TUESDAY. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 350 PM EDT SATURDAY... MODELS IN BETTER AGREEMENT TODAY ON A DEEP AND BROAD UPPER LOW CENTERED ACROSS THE EASTERN GREAT LAKES DOMINATING THE WEATHER THROUGH MOST OF THE REMAINDER OF THE WORK WEEK. THIS WILL LEAVE UNSETTLED CONDITIONS ACROSS THE MOUNTAINS...SOMEWHAT LESS SO ACROSS THE PIEDMONT. THE ECMWF HAS COME INTO BETTER AGREEMENT WITH THE GFS NOW ON A DISTURBANCE ROTATING THROUGH THE BOTTOM OF THE UPPER TROUGH WEDNESDAY...BRINGING A BETTER THREAT OF SHOWERS TO THE REGION. THUS...HAVE INCREASED POPS IN ACCORDANCE WITH THE BETTER MODEL AGREEMENT AND SURROUNDING OFFICES. HAVE NOT INTRODUCED THUNDER AT THIS POINT...BUT COULD NOT TOTALLY RULE OUT SOME THUNDER BECAUSE OF RATHER COLD AIR ALOFT. FOLLOWING THIS DISTURBANCE COMES THE BONAFIDE COLDER AIR WHICH PROMISES TO PUSH 850MB TEMPS DOWN TO 0C OR BELOW FOR MUCH OF THE REMAINDER OF THE WEEK ACROSS THE NORTHERN AREAS. THE UPPER TROUGH GRADUALLY SHIFTS MORE TOWARD THE MID-ATLANTIC LATE IN THE PERIOD...STRENGTHENING THE NORTHWEST FLOW ACROSS THE REGION...AND ALLOWING 850MB TEMPS TO BOTTOM OUT ACROSS THE NORTH AROUND -5C BY SATURDAY. THIS PATTERN WILL CONTINUE TO RESULT IN A SIGNIFICANT TEMPERATURE DIFFERENCE FROM THE WESTERN MOUNTAINS WITH CLOUDS AND VARIABLE CLOUDS/SCATTERED SHOWERS AND MORE SUNNY/DOWNSLOPE NORTHWEST FLOW ACROSS THE PIEDMONT. OVERALL...TEMPERATURES SHOULD AVERAGE BELOW NORMAL THROUGH THE PERIOD...PERHAPS MUCH BELOW IN THE WEST. MEXMOS SHOWS SEVERAL DAYS WITH HIGHS ONLY IN THE 50S/60S WEST AND LOWS IN THE UPPER 30S TO LOWER 40S. WIND AND CLOUDS SHOULD PREVENT ANY FROST/FREEZE CONCERN AT THIS POINT. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... AS OF 145 AM EDT SUNDAY... MODELS CONTINUE TO BE CONSISTENT WITH CLOUDS AND THEN RAIN WILL SPREAD INTO THE AREA FROM SOUTHWEST TO NORTHEAST TONIGHT. EXPECT CEILINGS TO LOWER TO MVFR ON THE 09Z/5AM-16Z/11AM TIME RANGE. A STRONG SOUTHEAST LOW LEVEL JET WILL DEVELOP JUST AFTER MIDNIGHT WHICH MAY BRING WIND GUSTS TO 30 KTS TODAY. WITH A WEDGE OF HIGH PRESSURE IN PLACE ALONG AND EAST OF THE BLUE RIDGE...AFTER SUNSET THESE STRONG WINDS ARE NOT EXPECTED TO REACH THE SURFACE. HAVE LLWS IN THE KDAN...KLWB AND KBCB TAFS AFTER 00Z/8PM. A STRONG UPSLOPE FLOW WILL TRANSPORT ABUNDANT MOISTURE INTO THE REGION NORTH OF A STATIONARY FRONT TODAY. CEILINGS WILL LOWER TO IFR LATE THIS AFTERNOON INTO THE EVENING AND WILL REMAIN LOW OVERNIGHT. EXTENDED AVIATION... A COLD FRONT APPROACHES LATER MONDAY WITH SOME STORMS POSSIBLE AHEAD OF AND ALONG THE FRONT...ESPECIALLY EAST OF THE BLUE RIDGE. THIS IS LIKELY TO KEEP PERIODS OF MVFR AND BRIEF IFR IN STORMS UNTIL THE FRONT CLEARS THE REGION MONDAY EVENING. VFR RETURNS LATER MONDAY NIGHT AND TUESDAY WITH HIGH PRESSURE BUILDING IN BEHIND THE FRONT WITH A DRIER AIRMASS. THEN THE NEXT CHANCE OF MVFR CONDITIONS AND PRECIPITATION WILL BE IN THE MOUNTAINS ON WEDNESDAY AND THURSDAY. && .HYDROLOGY... AS OF 330 PM EDT SATURDAY... ANTECEDENT CONDITIONS ARE STILL MOIST ACROSS THE NW NC MOUNTAINS/FOOTHILLS INTO THE SOUTHERN BLUE RIDGE OF VA WITH THE PERCENT OF NORMAL PRECIP OVER THE PAST WEEK EXCEEDING OVER 150%. THIS ALSO IS SHOWN IN RIVER STAGE LEVELS ACROSS THIS REGION FROM THE USGS WITH STREAM LEVELS IN MANY LOCATIONS RUNNING GREATER THAN THE 75TH PERCENTILE. WITH 6 HOUR FLASH FLOOD GUIDANCE VALUES BELOW 3 INCHES IN THE REGION...AND FORECAST PW VALUES 2-3 STANDARD DEVIATIONS ABOVE NORMAL...EXPECT FLOODING OF CREEKS AND STREAMS. WHILE THE SREF MODEL ENSEMBLE RIVER FORECAST ONLY IS FORECASTING A SMALL CHANCE FOR RIVERS TO REACH ACTION STAGE...WOULD NOT BE SURPRISED TO SEE A FEW SITES REACH MINOR FLOODING CONSIDERING THE MODEL TRENDS OF INCREASING QPF WITH EACH RUN. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...FLOOD WATCH THROUGH THIS EVENING FOR VAZ015>017-032. NC...FLOOD WATCH THROUGH THIS EVENING FOR NCZ001>003-018>020. WV...NONE. && $$ SYNOPSIS...PH NEAR TERM...PH/RCS SHORT TERM...RAB LONG TERM...RAB AVIATION...AMS/PC HYDROLOGY...PH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1158 AM CDT SUN APR 19 2015 UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE .SHORT TERM...TODAY...TONIGHT...AND MONDAY ISSUED AT 327 AM CDT SUN APR 19 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SPLIT FLOW OVER CENTRAL NORTH AMERICA EARLY THIS MORNING. IN THE SOUTHERN STREAM...UPPER LEVEL LOW PRESSURE IS SPINNING OVER WESTERN KANSAS/EASTERN COLORADO. AHEAD OF THIS FEATURE...SHOWERS AND THUNDERSTORMS ARE OCCURRING FROM NEBRASKA TO LOUISIANA. EVEN FURTHER NORTHEAST...MID-LEVEL MOISTURE TRANSPORT AND ILL-DEFINED SHORTWAVES ARE ALSO CREATING SHOWERS AND A FEW THUNDERSTORMS FROM WESTERN WISCONSIN INTO ILLINOIS. A COUPLE SPOTTY SHOWERS POPPED UP SHORTLY AFTER MIDNIGHT OVER WOOD COUNTY TO THE DELLS...AND WILL HAVE TO CARRY AN ISOLATED MENTION EARLY THIS MORNING ACROSS THE I-39/ROUTE 51 CORRIDOR. IN THE NORTHERN STREAM...SHORTWAVE ENERGY IS PROGRESSING EAST OVER THE NORTHWEST PLAINS. AS THESE FEATURES MOVE EAST...PRECIP CHANCES AND TIMING ARE THE MAIN FORECAST CONCERNS. TODAY...LOW PRESSURE OVER THE NORTHERN PLAINS WILL HEAD EAST WHILE THE SOUTHERN STREAM LOW WILL LIFT NORTHEAST OVER THE CENTRAL MISSISSIPPI VALLEY. WEAK SHORTWAVE ACTIVITY ROTATING ON THE EASTERN PERIPHERY OF THE UPPER LOW OVER WESTERN KANSAS WILL LIFT NORTH ACROSS THE WESTERN GREAT LAKES TODAY BUT INTO A MORE STABLE AND DRIER AIRMASS. DESPITE THIS...THE HIGHER RES MODELS AND RUC DEPICT SPOTTY SHOWERS DEVELOPING OVER CENTRAL AND NORTHEAST WISCONSIN THIS MORNING WHICH BEAR SOME WEIGHT GIVEN THE SPOTTY SHOWERS POPPING UP OVER THE DELLS AT THIS HOUR. AS A RESULT...QUITE DIFFICULT TO ADD MUCH TEMPORAL RESOLUTION TO THE FORECAST THIS MORNING OTHER THAN SAYING SLIGHT CHANCE OF A SHOWER. FORCING INCREASES OVER WESTERN WISCONSIN DURING THE AFTERNOON WHEN A FGEN BAND MOVES ACROSS THAT PART OF THE STATE. THE EASTERN EDGE OF THE INDUCED RAIN BAND WILL LIKELY BE PUSHING INTO N-C WISCONSIN LATE IN THE AFTERNOON. AM THINKING EASTERN WISCONSIN WILL REMAIN MOSTLY DRY DUE TO NE FLOW. THE SLOWER ARRIVAL OF THE PRECIP WILL HELP TEMPERATURES RISE INTO THE MID 60S OVER CENTRAL WI. CLOUD COVER AND EAST WINDS WILL SUPPORT MUCH COOLER READINGS OVER EASTERN WI THOUGH. TONIGHT...THE MEDIUM RANGE MODELS TRACK THE SOUTHERN STREAM SURFACE LOW FROM CENTRAL ILLINOIS/INDIANA TO NORTHERN LOWER MICHIGAN. SOME POSSIBILITY THAT THE LOW WILL TRACK WEST OF THIS LINE IN THE MESOMODELS THOUGH. COMMA HEAD PRECIP FROM THIS LOW LOOKS TO MOVE INTO NORTHEAST WISCONSIN BY MID TO LATE EVENING. MEANWHILE...RAIN BAND ASSOCIATED WITH MID-LEVEL FGEN AHEAD OF THE NORTHERN STREAM WAVE WILL SHIFT EAST THROUGH THE NIGHT ACROSS CENTRAL AND EASTERN WISCONSIN. SEEMS LIKE A GOOD RECIPE FOR PERIODS OF RAIN ACROSS THE REGION. LOWS RANGING FROM THE UPPER 30S NORTH TO MID 40S SOUTH. MONDAY...THE FGEN RAIN BAND WILL GRADUALLY BE WEAKENING AS IT MOVES EAST ACROSS EASTERN WISCONSIN DURING THE MORNING AND EXITS DURING THE AFTERNOON. THE MID-LEVEL DRY SLOT WILL WORK OVERHEAD IN THE WAKE OF THE RAIN DURING THE AFTERNOON AND MAY SEE A FEW PEAKS OF SUNSHINE. OTHERWISE...BECOMING BREEZY WITH HIGHS IN THE MID 40S NORTH TO LOW 50S SOUTH. .LONG TERM...MONDAY NIGHT THROUGH SATURDAY ISSUED AT 327 AM CDT SUN APR 19 2015 CLOSED UPPER LOW WILL BRING UNSETTLED AND COOL CONDITIONS TO THE REGION TUESDAY INTO WEDNESDAY. THE UPPER LOW WILL GRADUALLY PULL AWAY THURSDAY AND FRIDAY...BUT CYCLONIC FLOW COULD STILL BRING A SMALL CHANCE OF PRECIPITATION THURSDAY INTO FRIDAY ACROSS THE FAR NORTH. DESPITE THE CALENDER STATING ITS LATE APRIL...SOME SNOW IS IN THE FORECAST LATE AT NIGHT INTO THE MORNING HOURS. COULD BE SOME MINOR ACCUMULATION ACROSS THE FAR NORTH TUESDAY MORNING AND AGAIN WEDNESDAY MORNING. BELOW NORMAL TEMPERATURES WILL CONTINUE INTO NEXT WEEKEND WITH DRY CONDITIONS EXPECTED ON FRIDAY. ONLY MINOR CHANGES MADE TO PRECIPITATION CHANCES AND TEMPERATURES DURING THE PERIOD. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1146 AM CDT SUN APR 19 2015 BROKEN MIDLEVEL CIGS CONTINUE THIS AFTERNOON INTO THE EVENING...THOUGH VFR CONDITIONS SHOULD PREVAIL. LOW PRESSURE THEN MOVE ACROSS THE GREAT LAKES REGION TONIGHT AND WILL RESULT IN AN AREA OF STEADY RAIN OVERNIGHT. PRECIP SHOULD BE SLOWER TO ARRIVE THAN PREVIOUSLY FORECASTED...WITH RAIN ARRIVING LATE EARLY TONIGHT THROUGH MIDNIGHT. LOW END IFR CONDITIONS ARE EXPECTED WITH THIS AREA OF RAIN...WITH LIFR CIGS POSSIBLE AS CURRENT OBS IN AREA OF INCOMING PRECIP IN IL/IN SHOW SCATTERED CIGS BELOW 500FT. LIFR CONDITIONS IN CURRENT RAIN NOT WIDESPREAD ENOUGH AND GUIDANCE WAFFLING ON HOW LOW CIGS WILL GO...SO NOT ENOUGH CONFIDENCE TO ADD IT TO THE TAFS AT THIS TIME...BUT WILL BE SOMETHING TO MONITOR. HEAVIEST RAIN AND WORST CONDITIONS WILL LIKELY BE OVER EASTERN TAF SITES. RAIN WILL TAPER OFF MONDAY MORNING IN NORTH-CENTRAL WISCONSIN WITH MVFR CIGS POSSIBLE BY THE SECOND HALF OF THE MORNING. LIGHT RAIN WILL CONTINUE FURTHER EAST WITH IFR CONDITIONS MOST LIKELY HOLDING TIGHT UNTIL LATER IN THE MORNING. WINDS WILL BACK FROM SOUTHEAST THIS AFTERNOON...TO NORTH OVERNIGHT...TO NORTHEAST MONDAY AS A COLD FRONT SWEEPS THROUGH THE STATE. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......ALLEN
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
551 AM CDT SUN APR 19 2015 UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE .SHORT TERM...TODAY...TONIGHT...AND MONDAY ISSUED AT 327 AM CDT SUN APR 19 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SPLIT FLOW OVER CENTRAL NORTH AMERICA EARLY THIS MORNING. IN THE SOUTHERN STREAM...UPPER LEVEL LOW PRESSURE IS SPINNING OVER WESTERN KANSAS/EASTERN COLORADO. AHEAD OF THIS FEATURE...SHOWERS AND THUNDERSTORMS ARE OCCURRING FROM NEBRASKA TO LOUISIANA. EVEN FURTHER NORTHEAST...MID-LEVEL MOISTURE TRANSPORT AND ILL-DEFINED SHORTWAVES ARE ALSO CREATING SHOWERS AND A FEW THUNDERSTORMS FROM WESTERN WISCONSIN INTO ILLINOIS. A COUPLE SPOTTY SHOWERS POPPED UP SHORTLY AFTER MIDNIGHT OVER WOOD COUNTY TO THE DELLS...AND WILL HAVE TO CARRY AN ISOLATED MENTION EARLY THIS MORNING ACROSS THE I-39/ROUTE 51 CORRIDOR. IN THE NORTHERN STREAM...SHORTWAVE ENERGY IS PROGRESSING EAST OVER THE NORTHWEST PLAINS. AS THESE FEATURES MOVE EAST...PRECIP CHANCES AND TIMING ARE THE MAIN FORECAST CONCERNS. TODAY...LOW PRESSURE OVER THE NORTHERN PLAINS WILL HEAD EAST WHILE THE SOUTHERN STREAM LOW WILL LIFT NORTHEAST OVER THE CENTRAL MISSISSIPPI VALLEY. WEAK SHORTWAVE ACTIVITY ROTATING ON THE EASTERN PERIPHERY OF THE UPPER LOW OVER WESTERN KANSAS WILL LIFT NORTH ACROSS THE WESTERN GREAT LAKES TODAY BUT INTO A MORE STABLE AND DRIER AIRMASS. DESPITE THIS...THE HIGHER RES MODELS AND RUC DEPICT SPOTTY SHOWERS DEVELOPING OVER CENTRAL AND NORTHEAST WISCONSIN THIS MORNING WHICH BEAR SOME WEIGHT GIVEN THE SPOTTY SHOWERS POPPING UP OVER THE DELLS AT THIS HOUR. AS A RESULT...QUITE DIFFICULT TO ADD MUCH TEMPORAL RESOLUTION TO THE FORECAST THIS MORNING OTHER THAN SAYING SLIGHT CHANCE OF A SHOWER. FORCING INCREASES OVER WESTERN WISCONSIN DURING THE AFTERNOON WHEN A FGEN BAND MOVES ACROSS THAT PART OF THE STATE. THE EASTERN EDGE OF THE INDUCED RAIN BAND WILL LIKELY BE PUSHING INTO N-C WISCONSIN LATE IN THE AFTERNOON. AM THINKING EASTERN WISCONSIN WILL REMAIN MOSTLY DRY DUE TO NE FLOW. THE SLOWER ARRIVAL OF THE PRECIP WILL HELP TEMPERATURES RISE INTO THE MID 60S OVER CENTRAL WI. CLOUD COVER AND EAST WINDS WILL SUPPORT MUCH COOLER READINGS OVER EASTERN WI THOUGH. TONIGHT...THE MEDIUM RANGE MODELS TRACK THE SOUTHERN STREAM SURFACE LOW FROM CENTRAL ILLINOIS/INDIANA TO NORTHERN LOWER MICHIGAN. SOME POSSIBILITY THAT THE LOW WILL TRACK WEST OF THIS LINE IN THE MESOMODELS THOUGH. COMMA HEAD PRECIP FROM THIS LOW LOOKS TO MOVE INTO NORTHEAST WISCONSIN BY MID TO LATE EVENING. MEANWHILE...RAIN BAND ASSOCIATED WITH MID-LEVEL FGEN AHEAD OF THE NORTHERN STREAM WAVE WILL SHIFT EAST THROUGH THE NIGHT ACROSS CENTRAL AND EASTERN WISCONSIN. SEEMS LIKE A GOOD RECIPE FOR PERIODS OF RAIN ACROSS THE REGION. LOWS RANGING FROM THE UPPER 30S NORTH TO MID 40S SOUTH. MONDAY...THE FGEN RAIN BAND WILL GRADUALLY BE WEAKENING AS IT MOVES EAST ACROSS EASTERN WISCONSIN DURING THE MORNING AND EXITS DURING THE AFTERNOON. THE MID-LEVEL DRY SLOT WILL WORK OVERHEAD IN THE WAKE OF THE RAIN DURING THE AFTERNOON AND MAY SEE A FEW PEAKS OF SUNSHINE. OTHERWISE...BECOMING BREEZY WITH HIGHS IN THE MID 40S NORTH TO LOW 50S SOUTH. .LONG TERM...MONDAY NIGHT THROUGH SATURDAY ISSUED AT 327 AM CDT SUN APR 19 2015 CLOSED UPPER LOW WILL BRING UNSETTLED AND COOL CONDITIONS TO THE REGION TUESDAY INTO WEDNESDAY. THE UPPER LOW WILL GRADUALLY PULL AWAY THURSDAY AND FRIDAY...BUT CYCLONIC FLOW COULD STILL BRING A SMALL CHANCE OF PRECIPITATION THURSDAY INTO FRIDAY ACROSS THE FAR NORTH. DESPITE THE CALENDER STATING ITS LATE APRIL...SOME SNOW IS IN THE FORECAST LATE AT NIGHT INTO THE MORNING HOURS. COULD BE SOME MINOR ACCUMULATION ACROSS THE FAR NORTH TUESDAY MORNING AND AGAIN WEDNESDAY MORNING. BELOW NORMAL TEMPERATURES WILL CONTINUE INTO NEXT WEEKEND WITH DRY CONDITIONS EXPECTED ON FRIDAY. ONLY MINOR CHANGES MADE TO PRECIPITATION CHANCES AND TEMPERATURES DURING THE PERIOD. && .AVIATION...FOR 12Z TAF ISSUANCE ISSUED AT 551 AM CDT SUN APR 19 2015 BROKEN MID-LEVEL CLOUDS THROUGH THIS AFTERNOON WITH SPOTTY SHOWERS POSSIBLE. THEN AS LOW PRESSURE MOVES ACROSS THE REGION TONIGHT...STEADY RAIN WILL MOVE ACROSS THE TAF SITES BEGINNING THIS EVENING AND CONTINUING FOR MUCH OF THE NIGHT. EXPECT CIGS AND VSBYS TO LOWER ONCE THE RAIN ARRIVES. IFR CIGS LOOK LIKELY...AND SOME THREAT OF LIFR CIGS BASED ON UPSTREAM OBS OVER THE NORTHERN PLAINS AND MOS GUIDANCE. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......MPC
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND MONDAY ISSUED AT 327 AM CDT SUN APR 19 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SPLIT FLOW OVER CENTRAL NORTH AMERICA EARLY THIS MORNING. IN THE SOUTHERN STREAM...UPPER LEVEL LOW PRESSURE IS SPINNING OVER WESTERN KANSAS/EASTERN COLORADO. AHEAD OF THIS FEATURE...SHOWERS AND THUNDERSTORMS ARE OCCURRING FROM NEBRASKA TO LOUISIANA. EVEN FURTHER NORTHEAST...MID-LEVEL MOISTURE TRANSPORT AND ILL-DEFINED SHORTWAVES ARE ALSO CREATING SHOWERS AND A FEW THUNDERSTORMS FROM WESTERN WISCONSIN INTO ILLINOIS. A COUPLE SPOTTY SHOWERS POPPED UP SHORTLY AFTER MIDNIGHT OVER WOOD COUNTY TO THE DELLS...AND WILL HAVE TO CARRY AN ISOLATED MENTION EARLY THIS MORNING ACROSS THE I-39/ROUTE 51 CORRIDOR. IN THE NORTHERN STREAM...SHORTWAVE ENERGY IS PROGRESSING EAST OVER THE NORTHWEST PLAINS. AS THESE FEATURES MOVE EAST...PRECIP CHANCES AND TIMING ARE THE MAIN FORECAST CONCERNS. TODAY...LOW PRESSURE OVER THE NORTHERN PLAINS WILL HEAD EAST WHILE THE SOUTHERN STREAM LOW WILL LIFT NORTHEAST OVER THE CENTRAL MISSISSIPPI VALLEY. WEAK SHORTWAVE ACTIVITY ROTATING ON THE EASTERN PERIPHERY OF THE UPPER LOW OVER WESTERN KANSAS WILL LIFT NORTH ACROSS THE WESTERN GREAT LAKES TODAY BUT INTO A MORE STABLE AND DRIER AIRMASS. DESPITE THIS...THE HIGHER RES MODELS AND RUC DEPICT SPOTTY SHOWERS DEVELOPING OVER CENTRAL AND NORTHEAST WISCONSIN THIS MORNING WHICH BEAR SOME WEIGHT GIVEN THE SPOTTY SHOWERS POPPING UP OVER THE DELLS AT THIS HOUR. AS A RESULT...QUITE DIFFICULT TO ADD MUCH TEMPORAL RESOLUTION TO THE FORECAST THIS MORNING OTHER THAN SAYING SLIGHT CHANCE OF A SHOWER. FORCING INCREASES OVER WESTERN WISCONSIN DURING THE AFTERNOON WHEN A FGEN BAND MOVES ACROSS THAT PART OF THE STATE. THE EASTERN EDGE OF THE INDUCED RAIN BAND WILL LIKELY BE PUSHING INTO N-C WISCONSIN LATE IN THE AFTERNOON. AM THINKING EASTERN WISCONSIN WILL REMAIN MOSTLY DRY DUE TO NE FLOW. THE SLOWER ARRIVAL OF THE PRECIP WILL HELP TEMPERATURES RISE INTO THE MID 60S OVER CENTRAL WI. CLOUD COVER AND EAST WINDS WILL SUPPORT MUCH COOLER READINGS OVER EASTERN WI THOUGH. TONIGHT...THE MEDIUM RANGE MODELS TRACK THE SOUTHERN STREAM SURFACE LOW FROM CENTRAL ILLINOIS/INDIANA TO NORTHERN LOWER MICHIGAN. SOME POSSIBILITY THAT THE LOW WILL TRACK WEST OF THIS LINE IN THE MESOMODELS THOUGH. COMMA HEAD PRECIP FROM THIS LOW LOOKS TO MOVE INTO NORTHEAST WISCONSIN BY MID TO LATE EVENING. MEANWHILE...RAIN BAND ASSOCIATED WITH MID-LEVEL FGEN AHEAD OF THE NORTHERN STREAM WAVE WILL SHIFT EAST THROUGH THE NIGHT ACROSS CENTRAL AND EASTERN WISCONSIN. SEEMS LIKE A GOOD RECIPE FOR PERIODS OF RAIN ACROSS THE REGION. LOWS RANGING FROM THE UPPER 30S NORTH TO MID 40S SOUTH. MONDAY...THE FGEN RAIN BAND WILL GRADUALLY BE WEAKENING AS IT MOVES EAST ACROSS EASTERN WISCONSIN DURING THE MORNING AND EXITS DURING THE AFTERNOON. THE MID-LEVEL DRY SLOT WILL WORK OVERHEAD IN THE WAKE OF THE RAIN DURING THE AFTERNOON AND MAY SEE A FEW PEAKS OF SUNSHINE. OTHERWISE...BECOMING BREEZY WITH HIGHS IN THE MID 40S NORTH TO LOW 50S SOUTH. .LONG TERM...MONDAY NIGHT THROUGH SATURDAY ISSUED AT 327 AM CDT SUN APR 19 2015 CLOSED UPPER LOW WILL BRING UNSETTLED AND COOL CONDITIONS TO THE REGION TUESDAY INTO WEDNESDAY. THE UPPER LOW WILL GRADUALLY PULL AWAY THURSDAY AND FRIDAY...BUT CYCLONIC FLOW COULD STILL BRING A SMALL CHANCE OF PRECIPITATION THURSDAY INTO FRIDAY ACROSS THE FAR NORTH. DESPITE THE CALENDER STATING ITS LATE APRIL...SOME SNOW IS IN THE FORECAST LATE AT NIGHT INTO THE MORNING HOURS. COULD BE SOME MINOR ACCUMULATION ACROSS THE FAR NORTH TUESDAY MORNING AND AGAIN WEDNESDAY MORNING. BELOW NORMAL TEMPERATURES WILL CONTINUE INTO NEXT WEEKEND WITH DRY CONDITIONS EXPECTED ON FRIDAY. ONLY MINOR CHANGES MADE TO PRECIPITATION CHANCES AND TEMPERATURES DURING THE PERIOD. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1014 PM CDT SAT APR 18 2015 CLOUDS WILL CONTINUE TO THICKEN AND LOWER THROUGH THE NIGHT AND EARLY SUNDAY MORNING AS LOW PRESSURE SYSTEMS APPROACH FROM THE WEST AND SOUTH. RAIN IS EXPECTED TO BEGIN LATER SUNDAY MORNING ACROSS THE WEST AND SUNDAY AFTERNOON ACROSS THE EASTERN TAF SITES. TIMING OF THE RAIN SHOWERS IS A BIT TENUOUS AS THERE REMAINS SIGNIFICANT DIFFERENCES BETWEEN THE NWP MODELS. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......KURIMSKI
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
953 PM MDT MON APR 20 2015 .UPDATE... ISSUED AT 953 PM MDT MON APR 20 2015 MAIN CONCERN OVERNIGHT IS CERTAINLY THE POTENTIAL FOR FOG DEVELOPMENT FOR AREAS WEST OF THE LARAMIE RANGE...INCLUDING I-80 BETWEEN RAWLINS AND LARAMIE. 00Z NAM IS KEEPING FOG AT BAY WITH LOW BL HUMIDITIES AND A DRIER NEAR SURFACE LAYER BASED OFF THE KLAR FORECAST SOUNDINGS. HRRR IS ALSO CONSISTENTLY SHOWING NO DEVELOPMENT OF FOG OVERNIGHT. BASED ON THIS ENSEMBLE OF GUIDANCE...AND SOME MID CLOUDS DEVELOPING AND MOVING IN FROM THE NORTHWEST WITH A FORECAST WIND DIRECTION FROM THE SOUTHWEST...AM NOT SO CONFIDENT WIDESPREAD DENSE FOG WILL DEVELOP OVERNIGHT. LINGERING SNOWPACK AND LIGHT WINDS WILL CERTAINLY AID IN DEVELOPMENT OF MORE PATCHY AREAS OF FOG ESPECIALLY LATE IN THE NIGHT IN THE LARAMIE VALLEY...WITH VISIBILITIES DROPPING TO PERHAPS ONE HALF MILE OR SO...BUT A WIDESPREAD EVENT SEEMS UNLIKELY AT THIS TIME. THE HIGHEST PROBABILITY OF FOG WILL BE FOR EASTERN AND SOUTHERN PORTIONS OF THE LARAMIE VALLEY...AND PERHAPS NORTHERN CARBON COUNTY AS WELL. WILL HOLD OF ON ISSUING A DENSE FOG ADVISORY FOR NOW DUE TO LOW CONFIDENCE...BUT WILL CLOSELY MONITOR THE SITUATION. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 250 PM MDT MON APR 20 2015 TONIGHT...LOOKS LIKE ENOUGH INSTABILITY IN THE THETA E RIDGE ACROSS OUR FAR SOUTHWEST COUNTIES FOR ISOLATED TO WIDELY SCATTERED EARLY EVENING SHOWERS OVER SOUTHERN CARBON AND ALBANY COUNTIES. DRY ELSEWHERE. BASED ON PERSISTENCE...WILL AGAIN FORECAST AREAS OF FOG OVERNIGHT AND ESPECIALLY AFTER MIDNIGHT FOR MUCH OF CARBON COUNTY AND ESPECIALLY OVER THE LARAMIE VALLEY AND THE SNOWPACK WHERE TEMPERATURE AND DEWPOINT SPREADS ARE STILL ONLY 2 DEGREES AT MID AFTERNOON. TUESDAY...NON DESCRIPT NORTHWEST FLOW ALOFT CONTINUES. LOOKS LIKE ENOUGH LOW AND MID LEVEL MOISTURE ALONG WITH DIFFERENTIAL HEATING AND UPSLOPE TO GENERATE ISOLATED TO WIDELY SCATTERED AFTERNOON SHOWERS...WITH ISOLATED THUNDERSTORMS WEST OF INTERSTATE 25. TUESDAY NIGHT...SHOWERS AND THUNDERSTORMS SHOULD END IN THE EVENING WITH THE LOSS OF DAYTIME HEATING AND LACK OF SIGNIFICANT LIFTING...THOUGH STILL ENOUGH LOW AND MID LEVEL MOISTURE FOR SCATTERED TO BROKEN CLOUD COVER...AND AREAS OF FOG ONCE AGAIN OVER THE LARAMIE VALLEY. WEDNESDAY...TRANSITORY RIDGING ALOFT MOVES OVERHEAD. STILL THOUGH...ENOUGH LOW AND MID LEVEL MOISTURE AND INSTABILITY FOR ISOLATED TO SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS WITH AN INCREASE IN THUNDERSTORM COVERAGE DUE TO INCREASED INSTABILITY. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 250 PM MDT MON APR 20 2015 SHORTWAVE RIDGE MOVES OVER THE AREA WEDNESDAY NIGHT. MOST AREAS EAST OF THE LARAMIE RANGE WILL BE DRY...THOUGH GFS DOES SHOW SOME LIGHT SHOWERS OUT OVER CARBON COUNTY INTO THURSDAY MORNING. RIDGE AXIS MOVES EAST OF THE CWFA THURSDAY WITH AN UPPER SHORTWAVE PUSHING INTO NORTHWESTERN COLORADO AND WESTERN WYOMING. BOTH THE GFS AND ECMWF PAINTING MODERATE QPF OVER THE CWFA THURSDAY AFTERNOON. LIFTED INDICES -2 TO -4C ACROSS THE CWFA WITH -5 TO -6C ACROSS THE PANHANDLE. ADDED THUNDERSTORM MENTION IN THE FORECAST FOR THURSDAY AFTERNOON/EVENING. FRIDAY COULD BE AN INTERESTING DAY THUNDERSTORM WISE AS A SURFACE LOW DEVELOPS OVER NORTHEASTERN COLORADO. UPPER LEVEL LOW ALMOST VERTICALLY STACKED OVER THE SURFACE LOW ON BOTH THE GFS AND ECMWF. GFS MOST BULLISH ON QPF...WITH AN AREA OVER HEAVY RAIN OVER THE SOUTHERN PANHANDLE. LOW SLOW TO MOVE OUT OF THE AREA WITH SHOWER ACTIVITY CONTINUING INTO SATURDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 420 PM MDT MON APR 20 2015 GUSTY WEST AND NORTHWEST WINDS DECREASING BY EARLY THIS EVENING WITH RELATIVELY LIGHT WINDS OVERNIGHT. SCATTERED TO BROKEN CLOUDS TONIGHT FROM 4000 TO 8000 FEET AGL. AREAS OF FOG...WITH VISIBILITIES AT OR BELOW ONE MILE AT LARAMIE FROM 06Z TO 15Z WITH CEILINGS BELOW 1000 FEET AGL. NORTH AND NORTHWEST WINDS 20 TO 30 KNOTS DEVELOPING AGAIN TUESDAY BY LATE MORNING AND CONTINUING IN THE AFTERNOON WITH ISOLATED TO SCATTERED SHOWERS DEVELOPING. && .FIRE WEATHER... ISSUED AT 250 PM MDT MON APR 20 2015 RECENT RAIN AND CONTINUED SNOW PACK FROM LAST WEEKS STORM WILL KEEP FIRE WEATHER CONCERNS MINIMAL THROUGH THE WEEK. GOING TO SEE INCREASED CHANCES FOR WETTING RAINS AND MOUNTAIN SNOWS LATE IN THE WEEK AS ANOTHER PACIFIC LOW PRESSURE SYSTEM TRACKS ACROSS NORTHERN COLORADO. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...RJM SHORT TERM...RUBIN LONG TERM...GCC AVIATION...RUBIN FIRE WEATHER...GCC
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1123 PM MDT SAT APR 18 2015 .UPDATE... ISSUED AT 1108 PM MDT SAT APR 18 2015 CLOUD TOPS CONTINUE TO WARM ON IR IMAGERY...AND THE BAND OF MODERATE SNOW HAS SHIFTED EAST MORE INTO CENTRAL/SOUTHERN ALBANY COUNTY AND WESTERN LARAMIE COUNTY...SO ALLOWED THE WINTER HIGHLIGHTS TO EXPIRE. UPDATE ISSUED AT 945 PM MDT SAT APR 18 2015 THE BAND OF MODERATE TO LOCALLY HEAVY SNOW CONTINUES TO SLOWLY SHIFT EAST THIS EVENING...BUT PERHAPS SLIGHTLY SLOWER THAN PREVIOUS THINKING. EARLIER ANALYSIS SUGGESTED A FEW STRONGER SNOW SHOWERS WERE PERSISTING FROM THE NORTHERN LARAMIE RANGE SOUTHWEST THROUGH THE ARLINGTON AREA AND ON UP INTO THE SNOWY RANGE AND SOUTHERNMOST AREAS OF THE SIERRA MADRE MOUNTAINS. SHORT TERM MODELS ALSO SUGGESTED THAT THE BAND WOULD MOVE SLOW TO THE EAST THIS EVENING... SO FELT IT PRUDENT TO EXTEND THE WINTER STORM WARNING AND ADVISORY FOR A FEW MORE HOURS AS SNOW WOULD CONTINUE TO IMPACT THESE LOCATIONS. ENDED THE HEADLINES AT 11PM AS IR IMAGERY IS SHOWING A RAPID WARMING OF CLOUD TOPS...AND MODELS SUGGEST THE BAND WILL HAVE WEAKENED AND SHIFTED ENOUGH TO THE EAST TO CANCEL ALL WINTER HEADLINES AT THIS TIME. ALSO...ADDED AREAS OF FOG TO THE SUMMIT THROUGH MIDNIGHT AS WEBCAMS SHOWED THE DEVELOPMENT OF FOG EARLIER...AND HRRR KEEPS THE FOG AROUND THROUGH 11PM-12AM. .UPDATE ISSUED AT 546 PM MDT SAT APR 18 2015 TORNADO WATCH HAS BEEN CANCELLED. CONDITIONS ARE NO LONGER FAVORABLE FOR TORNADO DEVELOPMENT IN THE SOUTHERN NEBRASKA PANHANDLE WITH THE BOUNDARY LAYER STABILIZING. A FEW THUNDERSTORMS AREA STILL POSSIBLE OVER THE NEXT FEW HOURS INTO SOUTHEAST WYOMING AND PANHANDLE BUT SEVERE WEATHER IS VERY UNLIKELY. A ROUGE FUNNEL CLOUD AND SMALL HAIL STILL POSSIBLE FOR THE NEXT HOUR OR SO. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 440 PM MDT SAT APR 18 2015 LOTS OF WEATHER CONCERNS OVER THE NEXT 12 HOURS. HEAVY SNOW CONTINUES IN A NARROW BAND...MAINLY ACROSS EASTERN/CENTRAL CARBON COUNTY...STRETCHING NORTHEAST INTO THE NORTHERN LARAMIE RANGE. ON EITHER SIDE OF THE HEAVY BAND...MAINLY LOOKING AT LIGHT NON ACCUMULATING SNOW OR RAIN. THIS WILL CONTINUE TO BE THE CASE UNTIL LATE THIS EVENING WHEN THE DEFORMATION AXIS BEGINS TO SHIFT EAST AS THE NORTHWEST FLOW KICKER PUSHES THE UPPER LOW INTO THE PLAINS. THE BAND WILL SHIFT EAST LATE THIS EVENING INTO THE OVERNIGHT HOURS BUT IT WILL ALSO WEAKEN SUBSTANTIAL WILL LITTLE IN THE WAY OF ADDITION MEASURABLE PRECIPITATION AFTER MIDNIGHT ANYWHERE IN THE FORECAST AREA. SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER THE PLAINS. A TORNADO WATCH IS IN EFFECT FOR MORRILL AND CHEYENNE COUNTY IN THE SOUTHERN NEBRASKA PANHANDLE UNTIL 8 PM MDT. BASED ON RADAR TRENDS AND CURRENT ATMOSPHERIC ENVIRONMENT...ANY TORNADO THREAT IS RAPIDLY DECREASING. CURRENT SHOWER ACTIVITY WILL RAPIDLY STABILIZE THE BOUNDARY LAYER. ALSO...LIMITED SHEAR IS ONLY SUPPORTIVE OFF VERY SHORT LIVED AND WEAK TORNADIC ACTIVITY. WOULD NOT BE SURPRISED TO SEE A FEW FUNNEL CLOUD REPORTS WITH DEVELOPING SHOWERS AND THUNDERSTORMS AS THE OVERALL ENVIRONMENT IS MORE SUPPORTIVE OF FUNNEL CLOUDS BUT THAT TOO WILL QUICKLY WANE OVER THE NEXT FEW HOURS. ANOTHER CONCERN FOR TONIGHT IS NORTHERN WINDS WHICH WILL RAMP UP THIS EVENING INTO THE OVERNIGHT AS A COLD FRONT MOVES ACROSS THE AREA. COULD SEE A SHORT PERIOD OF NASTY WINTER CONDITIONS...MAINLY INTO THE SOUTHERN LARAMIE RANGE AND CHEYENNE AS THE SNOW BAND SHIFTS EAST AND INTERACTS WITH STRONG GUSTY NORTHERN WINDS. NAM AND GFS BUFKIT SOUNDINGS AROUND MIDNIGHT SHOWING 45 TO 50 KT WINDS AT CHEYENNE NOT TOO FAR OFF THE SURFACE. VERY WELL COULD SEE A 3 TO 4 HOUR PERIOD WITH LOW VISIBILITIES DUE TO FALLING SNOW AND GUSTY WINDS. FORTUNATELY THIS WILL BE SHORT LIVED IF IT THIS COMBINATIONS DOES INDEED OCCUR. ALSO WINDS SPEEDS WILL APPROACH WIND ADVISORY LEVELS INTO THE NEBRASKA PANHANDLE LATER TONIGHT AND INTO SUNDAY AFTERNOON. DID NOT ISSUE ANY WIND HEADLINES GIVEN WINTER WEATHER AND CONVECTIVE HEADLINES...BUT A WIND ADVISORY MAY BE NEEDED EVENTUALLY. QUIETER WEATHER ACROSS THE AREA SUNDAY WITH THE UPPER LOW OUT OF THE PICTURE. KEPT SOME LOW POPS GOING ACROSS THE WEST DURING THE DAY SUNDAY...BUT IT IS LOOKING LESS AND LESS LIKELY FOR ANY MEASURABLE PRECIPITATION FOR MOST OF SUNDAY. MAIN CHANCES WILL BE WITH NORTHERN STREAM SHORTWAVE AND UPPER LEVEL JET ENERGY WHICH SHOULD IMPACT THE SNOWY AND SIERRA MADRES SUNDAY NIGHT. ACCUMULATIONS WILL BE MINIMAL. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 250 PM MDT SAT APR 18 2015 MEDIUM TO LONG RANGE MODELS IN FAIR AGREEMENT THROUGH THE MIDDLE OF NEXT WEEK...WITH SOME DISAGREEMENT REGARDING THE TRACK AND EVOLUTION OF A DEVELOPING LOW PRESSURE SYSTEM LIFTING NORTHEAST ACROSS THE CENTRAL AND SOUTHERN ROCKY MOUNTAINS BY THURSDAY AND FRIDAY. FOR EARLY NEXT WEEK...ALL MODELS SHOW NORTHWEST FLOW INITIALLY WITH RELATIVELY DRY CONDITIONS LASTING INTO EARLY WEDNESDAY. A WEAK SHORTWAVE TROUGH WILL PUSH ACROSS THE REGION EMBEDDED IN THE NORTHWEST FLOW...BUT OUTSIDE OF SOME MOUNTAIN/HIGH VALLEY RAIN AND SNOW SHOWERS...DO NOT EXPECT ANYTHING SIGNIFICANT WITH HIGH TEMPERATURES ABOUT 10 TO 15 DEGREES COOLER THAN SEASONAL AVERAGES. TEMPERATURES WILL FINALLY MODERATE SOME BY TUES AND ESPECIALLY INTO WED...BACK INTO THE UPPER 50S TO UPPER 60S TO THE EAST OF THE LARAMIE RANGE. A SURFACE HIGH WILL BUILD OVER THE GREAT PLAINS LATE WEDNESDAY AND ON THURSDAY...RESULTING IN WINDS VEERING INTO THE EAST AND SOUTHEAST. KEPT TSTORMS IN THE FORECAST FOR THURSDAY WEST OF THE LARAMIE RANGE...BUT KEPT SHOWERS FURTHER EAST DUE TO A PERSISTENT LLVL STRATUS DECK. MODELS STRUGGLING WITH A SHORTWAVE DISTURBANCE LIFTING NORTHEAST OUT OF ARIZONA THURSDAY NIGHT. 12Z GFS ATTEMPTS TO FORM A CLOSED LOW ACROSS THE NORTH CENTRAL PLAINS OF COLORADO BY EARLY FRIDAY...WITH PRECIP EXTENDING INTO THE I80 CORRIDOR OF SOUTHEAST WYOMING AND WESTERN NEBRASKA. THE ECMWF ON THE OTHER HAND IS MUCH FURTHER SOUTH...MAINLY SHOWING THE FEATURE ACROSS NORTHERN NEW MEXICO LIFTING NORTHEAST INTO KANSAS BY FRIDAY. KEPT A 20 TO 30 PERCENT CHANCE OF RAIN AND HIGH ELEVATION SNOW FOR FRIDAY AND EARLY SATURDAY MORNING. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) AREAS OF MVFR AND IFR CIGS WILL AFFECT MOST TERMINALS OVERNIGHT WITH SOME RAIN AND SNOW EARLY IN THE PERIOD. GUSTY SFC WINDS EXPECTED ESPECIALLY OVER THE PLAINS TONIGHT AND SUNDAY. CIGS IMPVG DURING THE DAY SUNDAY. && .FIRE WEATHER... ISSUED AT 250 PM MDT SAT APR 18 2015 SHOWERS AND THUNDERSTORMS WILL END ACROSS ACROSS THE PLAINS TONIGHT WITH SNOW ENDING OVER HIGHER ELEVATIONS OF WYOMING AS THE UPPER LEVEL DISTURBANCE SHIFTS EAST INTO THE CENTRAL PLAINS. WARMING TREND THROUGH MID WEEK BUT GENERALLY ON THE COOLER SIDE AND DRY. NEXT CHANCE FOR WIDESPREAD PRECIPITATION IS LATE NEXT WEEK...MAYBE. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...RJM SHORT TERM...SML LONG TERM...TJT AVIATION...RE FIRE WEATHER...SML
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1108 PM MDT SAT APR 18 2015 .UPDATE... ISSUED AT 1108 PM MDT SAT APR 18 2015 CLOUD TOPS CONTINUE TO WARM ON IR IMAGERY...AND THE BAND OF MODERATE SNOW HAS SHIFTED EAST MORE INTO CENTRAL/SOUTHERN ALBANY COUNTY AND WESTERN LARAMIE COUNTY...SO ALLOWED THE WINTER HIGHLIGHTS TO EXPIRE. UPDATE ISSUED AT 945 PM MDT SAT APR 18 2015 THE BAND OF MODERATE TO LOCALLY HEAVY SNOW CONTINUES TO SLOWLY SHIFT EAST THIS EVENING...BUT PERHAPS SLIGHTLY SLOWER THAN PREVIOUS THINKING. EARLIER ANALYSIS SUGGESTED A FEW STRONGER SNOW SHOWERS WERE PERSISTING FROM THE NORTHERN LARAMIE RANGE SOUTHWEST THROUGH THE ARLINGTON AREA AND ON UP INTO THE SNOWY RANGE AND SOUTHERNMOST AREAS OF THE SIERRA MADRE MOUNTAINS. SHORT TERM MODELS ALSO SUGGESTED THAT THE BAND WOULD MOVE SLOW TO THE EAST THIS EVENING... SO FELT IT PRUDENT TO EXTEND THE WINTER STORM WARNING AND ADVISORY FOR A FEW MORE HOURS AS SNOW WOULD CONTINUE TO IMPACT THESE LOCATIONS. ENDED THE HEADLINES AT 11PM AS IR IMAGERY IS SHOWING A RAPID WARMING OF CLOUD TOPS...AND MODELS SUGGEST THE BAND WILL HAVE WEAKENED AND SHIFTED ENOUGH TO THE EAST TO CANCEL ALL WINTER HEADLINES AT THIS TIME. ALSO...ADDED AREAS OF FOG TO THE SUMMIT THROUGH MIDNIGHT AS WEBCAMS SHOWED THE DEVELOPMENT OF FOG EARLIER...AND HRRR KEEPS THE FOG AROUND THROUGH 11PM-12AM. .UPDATE ISSUED AT 546 PM MDT SAT APR 18 2015 TORNADO WATCH HAS BEEN CANCELLED. CONDITIONS ARE NO LONGER FAVORABLE FOR TORNADO DEVELOPMENT IN THE SOUTHERN NEBRASKA PANHANDLE WITH THE BOUNDARY LAYER STABILIZING. A FEW THUNDERSTORMS AREA STILL POSSIBLE OVER THE NEXT FEW HOURS INTO SOUTHEAST WYOMING AND PANHANDLE BUT SEVERE WEATHER IS VERY UNLIKELY. A ROUGE FUNNEL CLOUD AND SMALL HAIL STILL POSSIBLE FOR THE NEXT HOUR OR SO. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 440 PM MDT SAT APR 18 2015 LOTS OF WEATHER CONCERNS OVER THE NEXT 12 HOURS. HEAVY SNOW CONTINUES IN A NARROW BAND...MAINLY ACROSS EASTERN/CENTRAL CARBON COUNTY...STRETCHING NORTHEAST INTO THE NORTHERN LARAMIE RANGE. ON EITHER SIDE OF THE HEAVY BAND...MAINLY LOOKING AT LIGHT NON ACCUMULATING SNOW OR RAIN. THIS WILL CONTINUE TO BE THE CASE UNTIL LATE THIS EVENING WHEN THE DEFORMATION AXIS BEGINS TO SHIFT EAST AS THE NORTHWEST FLOW KICKER PUSHES THE UPPER LOW INTO THE PLAINS. THE BAND WILL SHIFT EAST LATE THIS EVENING INTO THE OVERNIGHT HOURS BUT IT WILL ALSO WEAKEN SUBSTANTIAL WILL LITTLE IN THE WAY OF ADDITION MEASURABLE PRECIPITATION AFTER MIDNIGHT ANYWHERE IN THE FORECAST AREA. SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER THE PLAINS. A TORNADO WATCH IS IN EFFECT FOR MORRILL AND CHEYENNE COUNTY IN THE SOUTHERN NEBRASKA PANHANDLE UNTIL 8 PM MDT. BASED ON RADAR TRENDS AND CURRENT ATMOSPHERIC ENVIRONMENT...ANY TORNADO THREAT IS RAPIDLY DECREASING. CURRENT SHOWER ACTIVITY WILL RAPIDLY STABILIZE THE BOUNDARY LAYER. ALSO...LIMITED SHEAR IS ONLY SUPPORTIVE OFF VERY SHORT LIVED AND WEAK TORNADIC ACTIVITY. WOULD NOT BE SURPRISED TO SEE A FEW FUNNEL CLOUD REPORTS WITH DEVELOPING SHOWERS AND THUNDERSTORMS AS THE OVERALL ENVIRONMENT IS MORE SUPPORTIVE OF FUNNEL CLOUDS BUT THAT TOO WILL QUICKLY WANE OVER THE NEXT FEW HOURS. ANOTHER CONCERN FOR TONIGHT IS NORTHERN WINDS WHICH WILL RAMP UP THIS EVENING INTO THE OVERNIGHT AS A COLD FRONT MOVES ACROSS THE AREA. COULD SEE A SHORT PERIOD OF NASTY WINTER CONDITIONS...MAINLY INTO THE SOUTHERN LARAMIE RANGE AND CHEYENNE AS THE SNOW BAND SHIFTS EAST AND INTERACTS WITH STRONG GUSTY NORTHERN WINDS. NAM AND GFS BUFKIT SOUNDINGS AROUND MIDNIGHT SHOWING 45 TO 50 KT WINDS AT CHEYENNE NOT TOO FAR OFF THE SURFACE. VERY WELL COULD SEE A 3 TO 4 HOUR PERIOD WITH LOW VISIBILITIES DUE TO FALLING SNOW AND GUSTY WINDS. FORTUNATELY THIS WILL BE SHORT LIVED IF IT THIS COMBINATIONS DOES INDEED OCCUR. ALSO WINDS SPEEDS WILL APPROACH WIND ADVISORY LEVELS INTO THE NEBRASKA PANHANDLE LATER TONIGHT AND INTO SUNDAY AFTERNOON. DID NOT ISSUE ANY WIND HEADLINES GIVEN WINTER WEATHER AND CONVECTIVE HEADLINES...BUT A WIND ADVISORY MAY BE NEEDED EVENTUALLY. QUIETER WEATHER ACROSS THE AREA SUNDAY WITH THE UPPER LOW OUT OF THE PICTURE. KEPT SOME LOW POPS GOING ACROSS THE WEST DURING THE DAY SUNDAY...BUT IT IS LOOKING LESS AND LESS LIKELY FOR ANY MEASURABLE PRECIPITATION FOR MOST OF SUNDAY. MAIN CHANCES WILL BE WITH NORTHERN STREAM SHORTWAVE AND UPPER LEVEL JET ENERGY WHICH SHOULD IMPACT THE SNOWY AND SIERRA MADRES SUNDAY NIGHT. ACCUMULATIONS WILL BE MINIMAL. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 250 PM MDT SAT APR 18 2015 MEDIUM TO LONG RANGE MODELS IN FAIR AGREEMENT THROUGH THE MIDDLE OF NEXT WEEK...WITH SOME DISAGREEMENT REGARDING THE TRACK AND EVOLUTION OF A DEVELOPING LOW PRESSURE SYSTEM LIFTING NORTHEAST ACROSS THE CENTRAL AND SOUTHERN ROCKY MOUNTAINS BY THURSDAY AND FRIDAY. FOR EARLY NEXT WEEK...ALL MODELS SHOW NORTHWEST FLOW INITIALLY WITH RELATIVELY DRY CONDITIONS LASTING INTO EARLY WEDNESDAY. A WEAK SHORTWAVE TROUGH WILL PUSH ACROSS THE REGION EMBEDDED IN THE NORTHWEST FLOW...BUT OUTSIDE OF SOME MOUNTAIN/HIGH VALLEY RAIN AND SNOW SHOWERS...DO NOT EXPECT ANYTHING SIGNIFICANT WITH HIGH TEMPERATURES ABOUT 10 TO 15 DEGREES COOLER THAN SEASONAL AVERAGES. TEMPERATURES WILL FINALLY MODERATE SOME BY TUES AND ESPECIALLY INTO WED...BACK INTO THE UPPER 50S TO UPPER 60S TO THE EAST OF THE LARAMIE RANGE. A SURFACE HIGH WILL BUILD OVER THE GREAT PLAINS LATE WEDNESDAY AND ON THURSDAY...RESULTING IN WINDS VEERING INTO THE EAST AND SOUTHEAST. KEPT TSTORMS IN THE FORECAST FOR THURSDAY WEST OF THE LARAMIE RANGE...BUT KEPT SHOWERS FURTHER EAST DUE TO A PERSISTENT LLVL STRATUS DECK. MODELS STRUGGLING WITH A SHORTWAVE DISTURBANCE LIFTING NORTHEAST OUT OF ARIZONA THURSDAY NIGHT. 12Z GFS ATTEMPTS TO FORM A CLOSED LOW ACROSS THE NORTH CENTRAL PLAINS OF COLORADO BY EARLY FRIDAY...WITH PRECIP EXTENDING INTO THE I80 CORRIDOR OF SOUTHEAST WYOMING AND WESTERN NEBRASKA. THE ECMWF ON THE OTHER HAND IS MUCH FURTHER SOUTH...MAINLY SHOWING THE FEATURE ACROSS NORTHERN NEW MEXICO LIFTING NORTHEAST INTO KANSAS BY FRIDAY. KEPT A 20 TO 30 PERCENT CHANCE OF RAIN AND HIGH ELEVATION SNOW FOR FRIDAY AND EARLY SATURDAY MORNING. && .AVIATION...(FOR THE 00Z TAFS THROUGH SUNDAY AFTERNOON) A BAND OF SNOW AND RAIN WILL REMAIN OVER CONVERSE...CARBON...AND ALBANY COUNTIES THIS EVENING...AND THEN WILL RAPIDLY PUSH SOUTHEAST NEAR A COLD FRONT...WHICH WILL PUSH SOUTHWARD TONIGHT. SCATTERED TSTORMS HAVE DEVELOPED NEAR KSNY AND JUST EAST OF KCYS THIS AFTERNOON. THESE TSTORMS WILL GRADUALLY MOVE NORTHWEST THIS AFTERNOON AND THIS EVENING. SMALL HAIL AND BRIEF HEAVY RAINFALL IS EXPECTED. A MORE STABLE AIRMASS WILL PUSH INTO THE REGION ON SUNDAY BEHIND A WEAK COLD FRONT...RESULTING IN LOW PRECIPITATION CHANCES ACROSS MOST OF THE FORECAST AREA. HOWEVER...IT WILL BE WINDY BEHIND THIS FRONT WITH NORTH WINDS BETWEEN 20 TO 30 KNOTS EAST OF THE LARAMIE RANGE. && .FIRE WEATHER... ISSUED AT 250 PM MDT SAT APR 18 2015 SHOWERS AND THUNDERSTORMS WILL END ACROSS ACROSS THE PLAINS TONIGHT WITH SNOW ENDING OVER HIGHER ELEVATIONS OF WYOMING AS THE UPPER LEVEL DISTURBANCE SHIFTS EAST INTO THE CENTRAL PLAINS. WARMING TREND THROUGH MID WEEK BUT GENERALLY ON THE COOLER SIDE AND DRY. NEXT CHANCE FOR WIDESPREAD PRECIPITATION IS LATE NEXT WEEK...MAYBE. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...RJM SHORT TERM...SML LONG TERM...TJT AVIATION...TJT FIRE WEATHER...SML
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1148 PM MDT MON APR 20 2015 .UPDATE... ISSUED AT 1139 PM MDT MON APR 20 2015 UPDATED TO ADJUST POPS THROUGH 2 AM. AREAS SOUTH OF HIGHWAY 50 CONTINUE TO SEE ISOLATED TO SCATTERED SHOWERS WHICH SHOULD DISSIPATE OVER THE NEXT COUPLE OF HOURS. NO OTHER UPDATES AT THIS TIME. MOZLEY UPDATE ISSUED AT 553 PM MDT MON APR 20 2015 UPDATED TO ADJUST SHOWER CHANCES ACROSS THE PLAINS...GENERALLY SOUTH OF HIGHWAY 50 FOR THIS EVENING. MOST HIGH-RES MODELS HAVE AN AREA OF SHOWER ACTIVITY DROPPING ACROSS THE PLAINS AND MADE ADJUSTMENTS TO ACCOUNT FOR THIS. NO OTHER UPDATES AT THIS TIME. MOZLEY && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 318 PM MDT MON APR 20 2015 CURRENTLY... MODEST NW FLOW PREVAILS ALOFT ACROSS THE REGION. ISOLD TO SCTD SHRA AND -TSRA WERE NOTED OVER THE HIGHER TRRN AND WERE MOVING ONTO THE PLAINS. MOST UNSTABLE ATMOSPHERE WAS NOTED OVER THE SPANISH PEAKS REGION PER RADAR AND TOTAL LTG DATA. TEMPS WERE COOL AT 3 PM WITH TEMPS IN THE U50S/L60S PLAINS AND 50S VALLEYS. REST OF TODAY AND THIS EVENING.... ISOLD PRECIP ACTIVITY WILL CONTINUE OVER THE HIGHER TRRN WITH SOME OF THIS ACTIVITY MOVING ONTO THE PLAINS. ANY ACTIVITY OVER THE PLAINS WILL GENERALLY REMAIN ISOLD...WITH A BIT MORE COVERAGE EXPECTED ALONG THE CO/NM BORDER. ACTIVITY WILL REMAIN WEAK WITH BIGGEST CONCERN BEING CG ACTIVITY. TONIGHT... ANY PRECIP OVER THE REGION WILL DIE BY LATER THIS EVENING IF NOT EARLIER. HRRR AND NAM GUIDANCE DO SHOW A TSTORM OR TWO OVER THE PLAINS EARLY THIS EVENING UNDER THE MODEST NW FLOW. TEMPS WILL COO INTO THE 30-35F RANGE ACROSS THE PLAINS WITH 20S IN THE VALLEYS. TUESDAY... IT WILL BE WARMER TOMORROW WITH HIGHS EXPECTED TO REACH INTO THE LOWER 70S MOST OF THE PLAINS...AND 60S VALLEYS. I DO EXPECT THAT WE WILL SEE A PRECIP PATTERN SIMILAR TO TODAY IN THAT SHOWERS AND STORMS WILL FORM OVER THE MTNS AND MOVE ONTO THE PLAINS. ACTIVITY WILL BE A LITTLE MORE ROBUST TOMORROW AS WE SHOULD SEE A BIT MORE INSTABILITY TOMORROW...HOWEVER NO STRONG ACTIVITY IS ANTICIPATED AT THIS TIME. /HODANISH .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 318 PM MDT MON APR 20 2015 RELATIVELY ACTIVE LONGER TERM IS ANTICIPATED WITH PRIMARY METEOROLOGICAL ISSUES BEING POPS(INCLUDING THUNDERSTORMS AND MOUNTAIN SNOWS)...TEMPERATURES AND GUSTY WINDS AT TIMES. RECENT LONGER TERM COMPUTER SIMULATIONS...FORECAST MODEL SOUNDINGS...PV ANALYSIS AND ADDITIONAL METEOROLOGICAL PARAMETERS SUGGEST THAT TRANSITORY UPPER RIDGING TO SOUTHWESTERLY UPPER FLOW WILL BE IN PLACE OVER THE FORECAST DISTRICT FROM TUESDAY NIGHT INTO THURSDAY IN ADVANCE OF NEXT UPPER DISTURBANCE IMPACTING CWFA FROM LATER THURSDAY INTO FRIDAY NIGHT WITH ANOTHER UPPER DISTURBANCE IMPACTING THE FORECAST DISTRICT FROM SATURDAY INTO SATURDAY NIGHT. AT LOWER LEVELS...SURFACE HIGH CENTERED OVER SOUTH DAKOTA AT 06Z WEDNESDAY SLOWLY SHIFTS INTO THE UPPER MIDWEST BY FRIDAY NIGHT...WHILE SURFACE LOW DEVELOPS OVER SOUTHEASTERN COLORADO BY 06Z FRIDAY BEFORE SHIFTING INTO OKLAHOMA BY 06Z SATURDAY AS NORTHERLY SURFACE SURGE PUSHES ACROSS EASTERN SECTIONS FRIDAY NIGHT. THE COMBINATION OF THESE METEOROLOGICAL PARAMETERS IN COMBINATION WITH ADEQUATE ATMOSPHERIC MOISTURE WILL ALLOW FOR UNSETTLED CONDITIONS AT TIMES OVER THE CWFA DURING THE MAJORITY OF THE LONGER TERM IN COMBINATION WITH TEMPERATURES RUNNING WITHIN A CATEGORY OR SO OF MID TO LATE APRIL CLIMATOLOGICAL AVERAGES MOST LOCATIONS...ALTHOUGH SOME ADDITIONAL WARMING IS PROJECTED TO DEVELOP BY EARLY NEXT WEEK. AT THIS TIME...IT APPEARS THAT THE HIGHEST POTENTIAL OF STRONGER CONVECTIVE POTENTIAL DURING THE LONGER TERM MAY BE REALIZED WEDNESDAY AND THURSDAY(ESPECIALLY EASTERN SECTIONS) AS DEEPER ATMOSPHERIC MOISTURE INTERACTS WITH UPPER IMPULSES TO PRODUCE LOCALIZED POTENTIAL CAPES/LIS AND BULK SHEARS VALUES OF -5C/1000+ J/KG AND 40 KNOTS RESPECTIVELY BOTH DAYS. AS ALWAYS...WFO PUEBLO WILL MONITOR CLOSELY. IN ADDITION...HIGHER ELEVATION ACCUMULATING SNOW IS ANTICIPATED AT TIMES WITH GUSTY GRADIENT WINDS ALSO POSSIBLE...PRIMARILY FROM FRIDAY INTO FRIDAY NIGHT. FINALLY...AS BRIEFLY TOUCHED UPON EARLIER...WARMEST CONDITIONS DURING THE LONGER TERM SHOULD BE NOTED BY NEXT MONDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1112 PM MDT MON APR 20 2015 VFR CONDITIONS EXPECTED AT THE TAF SITES OVER THE NEXT 24 HOURS. LIGHT WINDS TONIGHT WILL INCREASE OUT OF THE SOUTH TO SOUTHWEST ON TUESDAY...WITH SPEEDS UNDER 15 KTS. SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS TUESDAY AFTERNOON...A FEW OF WHICH WILL MOVE OFF INTO THE ADJACENT TERRAIN POTENTIALLY IMPACTING KCOS AND KALS. ALTHOUGH ODDS LOOK FAIRLY LOW THAT THE TERMINALS WILL BE IMPACTED...PATTERN LOOKS SIMILAR TO WHAT OCCURRED ON MONDAY...SO WILL CARRY VCSH IN THE TAFS AFTER 20Z FOR BOTH LOCATIONS. KPUB IS LESS LIKELY BE IMPACTED BY ANY PASSING SHOWERS. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MOZLEY AVIATION...KT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1117 PM MDT MON APR 20 2015 .UPDATE... ISSUED AT 553 PM MDT MON APR 20 2015 UPDATED TO ADJUST SHOWER CHANCES ACROSS THE PLAINS...GENERALLY SOUTH OF HIGHWAY 50 FOR THIS EVENING. MOST HIGH-RES MODELS HAVE AN AREA OF SHOWER ACTIVITY DROPPING ACROSS THE PLAINS AND MADE ADJUSTMENTS TO ACCOUNT FOR THIS. NO OTHER UPDATES AT THIS TIME. MOZLEY && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 318 PM MDT MON APR 20 2015 CURRENTLY... MODEST NW FLOW PREVAILS ALOFT ACROSS THE REGION. ISOLD TO SCTD SHRA AND -TSRA WERE NOTED OVER THE HIGHER TRRN AND WERE MOVING ONTO THE PLAINS. MOST UNSTABLE ATMOSPHERE WAS NOTED OVER THE SPANISH PEAKS REGION PER RADAR AND TOTAL LTG DATA. TEMPS WERE COOL AT 3 PM WITH TEMPS IN THE U50S/L60S PLAINS AND 50S VALLEYS. REST OF TODAY AND THIS EVENING.... ISOLD PRECIP ACTIVITY WILL CONTINUE OVER THE HIGHER TRRN WITH SOME OF THIS ACTIVITY MOVING ONTO THE PLAINS. ANY ACTIVITY OVER THE PLAINS WILL GENERALLY REMAIN ISOLD...WITH A BIT MORE COVERAGE EXPECTED ALONG THE CO/NM BORDER. ACTIVITY WILL REMAIN WEAK WITH BIGGEST CONCERN BEING CG ACTIVITY. TONIGHT... ANY PRECIP OVER THE REGION WILL DIE BY LATER THIS EVENING IF NOT EARLIER. HRRR AND NAM GUIDANCE DO SHOW A TSTORM OR TWO OVER THE PLAINS EARLY THIS EVENING UNDER THE MODEST NW FLOW. TEMPS WILL COO INTO THE 30-35F RANGE ACROSS THE PLAINS WITH 20S IN THE VALLEYS. TUESDAY... IT WILL BE WARMER TOMORROW WITH HIGHS EXPECTED TO REACH INTO THE LOWER 70S MOST OF THE PLAINS...AND 60S VALLEYS. I DO EXPECT THAT WE WILL SEE A PRECIP PATTERN SIMILAR TO TODAY IN THAT SHOWERS AND STORMS WILL FORM OVER THE MTNS AND MOVE ONTO THE PLAINS. ACTIVITY WILL BE A LITTLE MORE ROBUST TOMORROW AS WE SHOULD SEE A BIT MORE INSTABILITY TOMORROW...HOWEVER NO STRONG ACTIVITY IS ANTICIPATED AT THIS TIME. /HODANISH .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 318 PM MDT MON APR 20 2015 RELATIVELY ACTIVE LONGER TERM IS ANTICIPATED WITH PRIMARY METEOROLOGICAL ISSUES BEING POPS(INCLUDING THUNDERSTORMS AND MOUNTAIN SNOWS)...TEMPERATURES AND GUSTY WINDS AT TIMES. RECENT LONGER TERM COMPUTER SIMULATIONS...FORECAST MODEL SOUNDINGS...PV ANALYSIS AND ADDITIONAL METEOROLOGICAL PARAMETERS SUGGEST THAT TRANSITORY UPPER RIDGING TO SOUTHWESTERLY UPPER FLOW WILL BE IN PLACE OVER THE FORECAST DISTRICT FROM TUESDAY NIGHT INTO THURSDAY IN ADVANCE OF NEXT UPPER DISTURBANCE IMPACTING CWFA FROM LATER THURSDAY INTO FRIDAY NIGHT WITH ANOTHER UPPER DISTURBANCE IMPACTING THE FORECAST DISTRICT FROM SATURDAY INTO SATURDAY NIGHT. AT LOWER LEVELS...SURFACE HIGH CENTERED OVER SOUTH DAKOTA AT 06Z WEDNESDAY SLOWLY SHIFTS INTO THE UPPER MIDWEST BY FRIDAY NIGHT...WHILE SURFACE LOW DEVELOPS OVER SOUTHEASTERN COLORADO BY 06Z FRIDAY BEFORE SHIFTING INTO OKLAHOMA BY 06Z SATURDAY AS NORTHERLY SURFACE SURGE PUSHES ACROSS EASTERN SECTIONS FRIDAY NIGHT. THE COMBINATION OF THESE METEOROLOGICAL PARAMETERS IN COMBINATION WITH ADEQUATE ATMOSPHERIC MOISTURE WILL ALLOW FOR UNSETTLED CONDITIONS AT TIMES OVER THE CWFA DURING THE MAJORITY OF THE LONGER TERM IN COMBINATION WITH TEMPERATURES RUNNING WITHIN A CATEGORY OR SO OF MID TO LATE APRIL CLIMATOLOGICAL AVERAGES MOST LOCATIONS...ALTHOUGH SOME ADDITIONAL WARMING IS PROJECTED TO DEVELOP BY EARLY NEXT WEEK. AT THIS TIME...IT APPEARS THAT THE HIGHEST POTENTIAL OF STRONGER CONVECTIVE POTENTIAL DURING THE LONGER TERM MAY BE REALIZED WEDNESDAY AND THURSDAY(ESPECIALLY EASTERN SECTIONS) AS DEEPER ATMOSPHERIC MOISTURE INTERACTS WITH UPPER IMPULSES TO PRODUCE LOCALIZED POTENTIAL CAPES/LIS AND BULK SHEARS VALUES OF -5C/1000+ J/KG AND 40 KNOTS RESPECTIVELY BOTH DAYS. AS ALWAYS...WFO PUEBLO WILL MONITOR CLOSELY. IN ADDITION...HIGHER ELEVATION ACCUMULATING SNOW IS ANTICIPATED AT TIMES WITH GUSTY GRADIENT WINDS ALSO POSSIBLE...PRIMARILY FROM FRIDAY INTO FRIDAY NIGHT. FINALLY...AS BRIEFLY TOUCHED UPON EARLIER...WARMEST CONDITIONS DURING THE LONGER TERM SHOULD BE NOTED BY NEXT MONDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1112 PM MDT MON APR 20 2015 VFR CONDITIONS EXPECTED AT THE TAF SITES OVER THE NEXT 24 HOURS. LIGHT WINDS TONIGHT WILL INCREASE OUT OF THE SOUTH TO SOUTHWEST ON TUESDAY...WITH SPEEDS UNDER 15 KTS. SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS TUESDAY AFTERNOON...A FEW OF WHICH WILL MOVE OFF INTO THE ADJACENT TERRAIN POTENTIALLY IMPACTING KCOS AND KALS. ALTHOUGH ODDS LOOK FAIRLY LOW THAT THE TERMINALS WILL BE IMPACTED...PATTERN LOOKS SIMILAR TO WHAT OCCURRED ON MONDAY...SO WILL CARRY VCSH IN THE TAFS AFTER 20Z FOR BOTH LOCATIONS. KPUB IS LESS LIKELY BE IMPACTED BY ANY PASSING SHOWERS. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MOZLEY AVIATION...KT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
404 AM EDT TUE APR 21 2015 .SYNOPSIS... SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ALONG WITH MILD TEMPERATURES THIS MORNING...GIVES WAY TO A DRYING TREND THIS AFTERNOON. A COLD FRONT WILL BRING SCATTERED SHOWERS...AND PERHAPS EVEN AN ISOLATED THUNDERSTORM OR TWO...WEDNESDAY AFTERNOON AND EVENING. UNSEASONABLY COOL WEATHER FOLLOWS THURSDAY THROUGH THIS WEEKEND WITH JUST A SPOT SHOWER FROM TIME TO TIME. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATEST RUNS OF THE HRRR LOOK TO HAVE A VERY GOOD HANDLE ON THE FORECAST FOR THE NEXT SEVERAL HOURS THIS MORNING. LOTS OF ELEVATED CONVECTION ACROSS THE WESTERN HALF OF SOUTHERN NEW ENGLAND ALREADY THIS MORNING. SO FAR...THE MAIN HAZARDS HAVE BEEN THE LIGHTNING AND BRIEFLY TORRENTIAL RAINFALL. THESE STORMS WERE MOVING ALONG AT 35-45 MPH...SO AM NOT OVERLY CONCERNED ABOUT SIGNIFICANT WIDESPREAD FLOODING AT THIS TIME. SOME POOR DRAINAGE AREAS COULD EXPERIENCE NUISANCE FLOODING FOR A TIME THIS MORNING. WE WILL CONTINUE TO MONITOR RAINFALL RATES THOUGH. EXPECTING RAPID CLEARING BEHIND A WARM FRONT LATER THIS MORNING WITH TEMPERATURES SOARING INTO THE UPPER 60S TO NEAR 70 MOST LOCATIONS. WESTERLY WINDS WILL ALLOW EVEN THE COASTAL LOCATIONS TO GET IN ON THE WARM TEMPERATURES...UNLIKE THIS PAST SATURDAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... A SHORTWAVE WILL BE APPROACHING FROM THE WEST...BRINGING A CHANCE FOR SOME SHOWERS TO PORTIONS OF WESTERN MA BY DAYBREAK WEDNESDAY. WITH A COLD FRONT HAVING ALREADY PASSED THROUGH OUR REGION LATE THIS AFTERNOON...MODELS DO NOT SHOW MUCH RAINFALL AS INSTABILITY IS RATHER LIMITED. MUCH OF TONIGHT SHOULD REMAIN DRY ACROSS SOUTHERN NEW ENGLAND WITH SEASONABLE MINIMUM TEMPERATURES. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... HIGHLIGHTS... * SCATTERED SHOWERS WED WITH A LOW RISK OF THUNDER/SMALL HAIL * SEASONABLY MILD TEMPERATURES WED * UNSEASONABLY COOL THU-SUN WITH A SPOT SHOWER OR TWO AT TIMES OVERVIEW... OVERALL THE 12Z GUIDANCE IS IN GOOD AGREEMENT WITHIN THE MEDIUM AND LONG RANGE. HOWEVER EXACT TIMING AND STRENGTH OF EACH SYSTEM STILL NEEDS TO BE WORKED OUT. UPPER LEVEL LOW WILL CONTINUE TO DOMINATE THE REGION THROUGH THE EXTENDED...PINWHEELING BETWEEN THE GREAT LAKES AND NEW ENGLAND. THIS SYSTEM WILL YIELD TO A MORE SHOWERY AND COOLER FORECAST FOR THE REST OF THE WEEK AND INTO THE WEEKEND. DETAILS... * WEDNESDAY AND WEDNESDAY NIGHT...MODERATE CONFIDENCE. STRONG SHORTWAVE WILL MOVE THROUGH THE FLOW ON WEDNESDAY DEVELOPING A SURFACE LOW ACROSS HUDSON RIVER VALLEY AND INTO SOUTHERN NEW ENGLAND. THIS LOW WILL BRING SCT RAIN SHOWERS AND ISOLATED THUNDER TO THE AREA BY THE AFTERNOON HOURS. APPEARS WE MAY TRY TO WARM SECTOR ALLOWING SURFACE TEMPS TO REACH INTO THE LOW TO MID 60S. THIS WILL STEEPEN THE LAPSE RATES TO AROUND 7-8 C/KM AS 500 MB TEMPS ARE -24C. MODEL GUIDANCE IS ALSO INDICATING THAT SOME SURFACE CAPE MAY DEVELOP WHICH WILL HELP IN THUNDERSTORM DEVELOPMENT. IN FACT WE COULD SEE SMALL HAIL/GRAUPEL AS FREEZING HEIGHTS WILL BE LOW THANKS TO THE COLD POOL. STILL A LOT OF DETAILS TO WORK OUT BUT SOMETHING TO WATCH IN THE COMING DAY. * THURSDAY INTO MONDAY...MODERATE CONFIDENCE. STRONG CUT OFF LOW WILL CONTINUE TO SPIN OVER THE NORTHEAST DURING THIS TIME PERIOD. NEW ENGLAND COULD SEE A SEVERAL WAVES DEVELOP AND PUSH THROUGH THE REGION. HOWEVER MAY SEE A LOT OF DIURNAL CU AND DIURNAL SHOWERS DEVELOPING RATHER THAN WIDESPREAD RAIN. THESE SHOWERS WILL BE DIURNALLY DRIVEN AS COLD POOL ALOFT WILL BE OVERHEAD STEEPENING THE LAPSE RATES. AREAS THAT HAVE THE BEST CHANCE FOR ANY PRECIP WILL BE NORTH OF THE PIKE...CLOSER TO THE LOW PRESSURE. LASTLY EXPECT TEMPS TO BE ABOUT 5-10 F BELOW AVERAGE FOR THE WEEK THANKS TO THE COOLER TEMPS ALOFT VIA THE COLD POOL. IN FACT SOME AREAS MAY NOT SEE THE 60S FOR THE REST OF THE WEEK AND INTO THE WEEKEND. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT-TERM /THROUGH TUESDAY/... THROUGH 12Z...LINE OF ELEVATED THUNDERSTORMS MOVES INTO THE CENTRAL AND EASTERN SECTIONS OF SOUTHERN NEW ENGLAND. BRIEF GUSTY WINDS AND TORRENTIAL RAINFALL ARE THE BIGGEST THREATS. TODAY...CONDITIONS IMPROVING TO VFR BY MIDDAY. COLD FRONT MOVES THROUGH WITH WINDS SHIFTING W/SW THIS AFTERNOON. TONIGHT...HIGH CONFIDENCE IN MAINLY VFR CONDITIONS DESPITE THE RISK FOR A SPOT SHOWER OR TWO. KBOS TAF...HIGH CONFIDENCE IN TRENDS. MODERATE CONFIDENCE IN TIMING. MORNING PUSH LIKELY TO BE AFFECTED. ALSO LOW RISK OF A THUNDERSTORM BETWEEN 08Z AND 12Z. KBDL TAF...HIGH CONFIDENCE IN TRENDS. MODERATE CONFIDENCE IN TIMING. RISK FOR THUNDERSTORMS HAS LIKELY MOVED EAST OF THE TERMINAL FOR THE REST OF THIS MORNING. OUTLOOK...WEDNESDAY THROUGH SATURDAY... WED...MODERATE CONFIDENCE. A COLD FRONT WILL BRING A ROUND OF SCATTERED SHOWERS MAINLY WED AFTERNOON/EARLY EVENING. LOW RISK FOR EVEN A FEW RUMBLES OF THUNDER AND PERHAPS SMALL HAIL/GRAUPEL WITH THE HEAVIEST SHOWERS. THU/FRI/SAT...HIGH CONFIDENCE. MAINLY VFR. CONDITIONS COULD LOWER TO MVFR QUICKLY IN A BRIEF DIURNALLY DRIVEN SHOWER OR TWO. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TONIGHT/... WILL LIKELY BE ABLE TO CONVERT THE REST OF THE GALE WARNINGS FOR THE OUTER SOUTHERN NEW ENGLAND WATERS TO SMALL CRAFT ADVISORIES. STILL NEED TO WATCH FOR THUNDERSTORMS THIS MORNING...SOME OF WHICH COULD PRODUCE BRIEF GUSTS UP TO 35 KT. VISIBILITY IMPROVES LATER TODAY WITH WINDS AND SEAS CONTINUING TO DIMINISH TONIGHT. VISIBILITIES MAY BE LIMITED AT TIMES. OUTLOOK...WEDNESDAY THROUGH SATURDAY... WEDNESDAY...HIGH CONFIDENCE. MODEST WEST TO SOUTHWEST FLOW EXPECTED AHEAD OF A COLD FRONT...BUT SPEEDS WILL BE NEAR SCA ESP ACROSS THE NEAR SHORE WATERS. A FEW SHOWERS WED AFTERNOON AND EVENING WITH A LOW RISK OF AN ISOLATED THUNDERSTORM WITH SMALL HAIL. THURSDAY THROUGH SATURDAY...HIGH CONFIDENCE. MODEST WESTERLY FLOW AS A RESULT OF CLOSED LOW PRESSURE ACROSS QUEBEC. ENOUGH COLD ADVECTION OVER THE WATERS WILL BE PRESENT TO GENERATE PERIODS OF 25 KNOT WIND GUSTS. MARGINAL SCA SEAS EXPECTED ACROSS THE OUTER-WATERS AT TIMES...BUT WITH GOOD VISIBILITY. && .TIDES/COASTAL FLOODING... EAST TO SOUTHEAST WINDS WILL INCREASE THROUGH TONIGHT. GUIDANCE CONTINUES TO TRACK STRONGEST WINDS ACROSS NEW ENGLAND EARLY THIS EVENING...BEFORE HIGH TIDE OCCURS ALONG THE SOUTH COAST /AROUND 03Z/ AND EAST COAST /ABOUT 06Z/. THIS RESULTS IN WINDS BEGINNING TO SLACKEN AS HIGH TIDE APPROACHES. ALSO SYSTEM IS FAIRLY PROGRESSIVE SO DURATION OF ONSHORE WINDS IS LIMITED. ESTOFS CONTINUES TO BE MORE ROBUST AND REALISTIC THAN ETSS WITH SURGE VALUES 1.0-1.5 FT AT THE TIME OF HIGH TIDE. SEAS ALSO BUILDING TO 10-15 FT JUST OFFSHORE. THIS SHOULD BE SUFFICIENT TO GENERATE AREAS OF MINOR COASTAL FLOODING AND SPLASH OVER. THUS WILL CONTINUE WITH A COASTAL FLOOD ADVISORY FOR THESE LOCATIONS DURING THIS EVENING AND EARLY TUE MORNING HIGH TIDES. WINDS DO NOT LOOK STRONG ENOUGH AT THE TIME OF HIGH TIDE FOR A MODERATE COASTAL FLOOD EVENT. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT WEDNESDAY FOR ANZ235-237- 250-254>256. SMALL CRAFT ADVISORY UNTIL NOON EDT WEDNESDAY FOR ANZ251. && $$ SYNOPSIS...BELK/DUNTEN NEAR TERM...BELK SHORT TERM...BELK LONG TERM...DUNTEN AVIATION...BELK/DUNTEN MARINE...BELK/DUNTEN TIDES/COASTAL FLOODING...STAFF
AREA FORECAST DISCUSSION
NWS TAUNTON MA
321 AM EDT TUE APR 21 2015 .SYNOPSIS... SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ALONG WITH MILD TEMPERATURES THIS MORNING...GIVES WAY TO A DRYING TREND THIS AFTERNOON. A COLD FRONT WILL BRING SCATTERED SHOWERS...AND PERHAPS EVEN AN ISOLATED THUNDERSTORM OR TWO...WEDNESDAY AFTERNOON AND EVENING. UNSEASONABLY COOL WEATHER FOLLOWS THURSDAY THROUGH THIS WEEKEND WITH JUST A SPOT SHOWER FROM TIME TO TIME. && .NEAR TERM /THROUGH TODAY/... LATEST RUNS OF THE HRRR LOOK TO HAVE A VERY GOOD HANDLE ON THE FORECAST FOR THE NEXT SEVERAL HOURS THIS MORNING. LOTS OF ELEVATED CONVECTION ACROSS THE WESTERN HALF OF SOUTHERN NEW ENGLAND ALREADY THIS MORNING. SO FAR...THE MAIN HAZARDS HAVE BEEN THE LIGHTNING AND BRIEFLY TORRENTIAL RAINFALL. THESE STORMS WERE MOVING ALONG AT 35-45 MPH...SO AM NOT OVERLY CONCERNED ABOUT SIGNIFICANT WIDESPREAD FLOODING AT THIS TIME. SOME POOR DRAINAGE AREAS COULD EXPERIENCE NUISANCE FLOODING FOR A TIME THIS MORNING. WE WILL CONTINUE TO MONITOR RAINFALL RATES THOUGH. EXPECTING RAPID CLEARING BEHIND A WARM FRONT LATER THIS MORNING WITH TEMPERATURES SOARING INTO THE UPPER 60S TO NEAR 70 MOST LOCATIONS. WESTERLY WINDS WILL ALLOW EVEN THE COASTAL LOCATIONS TO GET IN ON THE WARM TEMPERATURES...UNLIKE THIS PAST SATURDAY. && .SHORT TERM /TONIGHT/... A SHORTWAVE WILL BE APPROACHING FROM THE WEST...BRINGING A CHANCE FOR SOME SHOWERS TO PORTIONS OF WESTERN MA BY DAYBREAK WEDNESDAY. WITH A COLD FRONT HAVING ALREADY PASSED THROUGH OUR REGION LATE THIS AFTERNOON...MODELS DO NOT SHOW MUCH RAINFALL AS INSTABILITY IS RATHER LIMITED. MUCH OF TONIGHT SHOULD REMAIN DRY ACROSS SOUTHERN NEW ENGLAND WITH SEASONABLE MINIMUM TEMPERATURES. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... HIGHLIGHTS... * SCATTERED SHOWERS WED WITH A LOW RISK OF THUNDER/SMALL HAIL * SEASONABLY MILD TEMPERATURES WED * UNSEASONABLY COOL THU-SUN WITH A SPOT SHOWER OR TWO AT TIMES DETAILS... WEDNESDAY AND WEDNESDAY NIGHT... A FAIRLY STRONG SHORTWAVE AND ASSOCIATED COLD FRONT WILL CROSS THE REGION WED AFTERNOON AND EVENING. HIGH TEMPS SHOULD STILL REACH INTO INTO THE UPPER 50S TO MIDDLE 60S AHEAD OF THE FRONT. WE WILL SEE SCATTERED SHOWERS WITH THE FRONT GIVEN DECENT FORCING AND SOME MARGINAL INSTABILITY. MOST LIKELY TIME FRAME IS WED AFTERNOON AND EARLY EVENING. ITS QUITE COLD ALOFT AND MID LEVEL LAPSE RATES ARE VERY IMPRESSIVE AROUND 8C/KM! IF WE CAN MUSTER A FEW HUNDRED J/KG OF CAPE...MAY EVEN SEE AN EMBEDDED THUNDERSTORM OR TWO. CONFIDENCE ON THUNDER IS LOW AT THIS POINT...BUT GIVEN COLD POOL ALOFT THERE IS AT LEAST THIS RISK FOR SOME GRAUPEL/SMALL HAIL AND PERHAPS EVEN GUSTY WINDS IN THE HEAVIEST SHOWERS. THIS ACTIVITY SHOULD WIND DOWN BY WED EVENING. THURSDAY THROUGH MONDAY... ANOMALOUS CLOSED UPPER LEVEL LOW SETS UP ACROSS NORTHERN NEW ENGLAND AND INTO QUEBEC. THE RESULT WILL BE BELOW NORMAL HEIGHTS AND COOLER THAN NORMAL TEMPS IN SOUTHERN NEW ENGLAND. OVERALL...HIGH TEMPS WILL RANGE FROM THE UPPER 40S TO MIDDLE 50S MUCH OF THE TIME BUT SOME MODERATION IS POSSIBLE BY MONDAY. AS FOR PRECIP CHANCES...THE VAST MAJORITY OF THE TIME SHOULD FEATURE DRY WEATHER. HOWEVER...GIVEN COLD POOL ALOFT A FEW SPOT SHOWERS WILL BE POSSIBLE AT TIMES...ESPECIALLY IN NORTHERN SECTIONS DURING THE AFTERNOON HOURS. LOW RISK FOR EVEN A FEW WET SNOW FLAKES TO MIX IN FOR A TIME ACROSS THE HIGHER TERRAIN...BUT WOULD BE OF NO IMPACT. THERE IS ONE FLY IN THE OINTMENT. WE WILL HAVE TO WATCH A MORE SIGNIFICANT LOW PRESSURE SYSTEM SAT NIGHT/SUN. MOST OF THE MODEL GUIDANCE KEEPS THAT SYSTEM WELL TO OUR SOUTH. THE 12Z ECMWF IS A BIT CLOSER THEN THE REST OF THE GUIDANCE...BUT EVEN THAT WOULD KEEP US DRY. AGAIN...ODDS STRONGLY FAVOR KEEPING THIS SYSTEM SOUTH OR OUR REGION GIVEN ANOMALOUS CLOSED LOW SITTING JUST TO OUR NORTH. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT-TERM /THROUGH TUESDAY/... THROUGH 12Z...LINE OF ELEVATED THUNDERSTORMS MOVES INTO THE CENTRAL AND EASTERN SECTIONS OF SOUTHERN NEW ENGLAND. BRIEF GUSTY WINDS AND TORRENTIAL RAINFALL ARE THE BIGGEST THREATS. TODAY...CONDITIONS IMPROVING TO VFR BY MIDDAY. COLD FRONT MOVES THROUGH WITH WINDS SHIFTING W/SW THIS AFTERNOON. TONIGHT...HIGH CONFIDENCE IN MAINLY VFR CONDITIONS DESPITE THE RISK FOR A SPOT SHOWER OR TWO. KBOS TAF...HIGH CONFIDENCE IN TRENDS. MODERATE CONFIDENCE IN TIMING. MORNING PUSH LIKELY TO BE AFFECTED. ALSO LOW RISK OF A THUNDERSTORM BETWEEN 08Z AND 12Z. KBDL TAF...HIGH CONFIDENCE IN TRENDS. MODERATE CONFIDENCE IN TIMING. RISK FOR THUNDERSTORMS HAS LIKELY MOVED EAST OF THE TERMINAL FOR THE REST OF THIS MORNING. OUTLOOK...WEDNESDAY THROUGH SATURDAY... WED...MODERATE CONFIDENCE. A COLD FRONT WILL BRING A ROUND OF SCATTERED SHOWERS MAINLY WED AFTERNOON/EARLY EVENING. LOW RISK FOR EVEN A FEW RUMBLES OF THUNDER AND PERHAPS SMALL HAIL/GRAUPEL WITH THE HEAVIEST SHOWERS. THU/FRI/SAT...HIGH CONFIDENCE. MAINLY VFR DESPITE THE RISK FOR A BRIEF DIURNALLY DRIVEN SHOWER OR TWO. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TONIGHT/... WILL LIKELY BE ABLE TO CONVERT THE REST OF THE GALE WARNINGS FOR THE OUTER SOUTHERN NEW ENGLAND WATERS TO SMALL CRAFT ADVISORIES. STILL NEED TO WATCH FOR THUNDERSTORMS THIS MORNING...SOME OF WHICH COULD PRODUCE BRIEF GUSTS UP TO 35 KT. VISIBILITY IMPROVES LATER TODAY WITH WINDS AND SEAS CONTINUING TO DIMINISH TONIGHT. VISIBILITIES MAY BE LIMITED AT TIMES. OUTLOOK...WEDNESDAY THROUGH SATURDAY... WEDNESDAY...HIGH CONFIDENCE. MODEST WEST TO SOUTHWEST FLOW EXPECTED AHEAD OF A COLD FRONT...BUT SPEEDS SHOULD REMAIN BELOW SMALL CRAFT THRESHOLDS. A FEW SHOWERS WED AFTERNOON AND EVENING WITH A LOW RISK OF AN ISOLATED THUNDERSTORM WITH SMALL HAIL. THURSDAY THROUGH SATURDAY...HIGH CONFIDENCE. MODEST WESTERLY FLOW AS A RESULT OF CLOSED LOW PRESSURE ACROSS QUEBEC. ENOUGH COLD ADVECTION OVER THE WATERS WILL BE PRESENT TO GENERATE PERIODS OF 25 KNOT WIND GUSTS. MARGINAL SCA SEAS EXPECTED ACROSS THE OUTER-WATERS AT TIMES...BUT WITH GOOD VISIBILITY. && .TIDES/COASTAL FLOODING... EAST TO SOUTHEAST WINDS WILL INCREASE THROUGH TONIGHT. GUIDANCE CONTINUES TO TRACK STRONGEST WINDS ACROSS NEW ENGLAND EARLY THIS EVENING...BEFORE HIGH TIDE OCCURS ALONG THE SOUTH COAST /AROUND 03Z/ AND EAST COAST /ABOUT 06Z/. THIS RESULTS IN WINDS BEGINNING TO SLACKEN AS HIGH TIDE APPROACHES. ALSO SYSTEM IS FAIRLY PROGRESSIVE SO DURATION OF ONSHORE WINDS IS LIMITED. ESTOFS CONTINUES TO BE MORE ROBUST AND REALISTIC THAN ETSS WITH SURGE VALUES 1.0-1.5 FT AT THE TIME OF HIGH TIDE. SEAS ALSO BUILDING TO 10-15 FT JUST OFFSHORE. THIS SHOULD BE SUFFICIENT TO GENERATE AREAS OF MINOR COASTAL FLOODING AND SPLASH OVER. THUS WILL CONTINUE WITH A COASTAL FLOOD ADVISORY FOR THESE LOCATIONS DURING THIS EVENING AND EARLY TUE MORNING HIGH TIDES. WINDS DO NOT LOOK STRONG ENOUGH AT THE TIME OF HIGH TIDE FOR A MODERATE COASTAL FLOOD EVENT. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...COASTAL FLOOD ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR MAZ007-015-016-019-022-024. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR ANZ231>234. SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR ANZ230-236. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ235-237- 251. GALE WARNING UNTIL 4 AM EDT EARLY THIS MORNING FOR ANZ250- 254>256. && $$ SYNOPSIS...BELK/FRANK NEAR TERM...BELK SHORT TERM...BELK LONG TERM...FRANK AVIATION...BELK/FRANK MARINE...BELK/FRANK TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS ALBANY NY
1252 AM EDT TUE APR 21 2015 .SYNOPSIS... .A LOW PRESSURE SYSTEM APPROACHING FROM THE WEST WITH ASSOCIATED FRONTS WILL BRING OCCASIONAL SHOWERS TO THE AREA ALONG WITH A FEW RUMBLES OF THUNDER TONIGHT. WITH A LARGE STATIONARY LOW OVER THE REGION...UNSETTLED WEATHER WILL CONTINUE THROUGH THE WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1245 AM EDT...A LINE OF SHOWERS AND EMBEDDED THUNDERSTORMS HAS NOW ENTERED WESTERN PORTIONS OF THE FORECAST AREA...EXTENDING FROM THE WESTERN ADIRONDACKS SOUTH INTO THE WESTERN MOHAWK VALLEY...SCHOHARIE VALLEY...AND INTO THE EASTERN CATSKILLS. ADDITIONAL SHOWERS AND THUNDERSTORMS HAVE FORMED AHEAD OF THIS LINE ACROSS THE MID HUDSON VALLEY AND SE CATSKILLS...AND ARE TRANSLATING NORTH/NORTHEAST. WE EXPECT SHOWERS AND THUNDERSTORMS TO CONTINUE EXPANDING EAST/NORTHEAST OVER THE NEXT 2-4 HOURS. SOME THUNDERSTORMS COULD CONTAIN LOCALLY HVY DOWNPOURS...AND ISOLATED GUSTY WINDS. IN ADDITION...SOME SMALL HAIL IS POSSIBLE WITHIN THE TALLER CONVECTIVE ELEMENTS...AS WE HAD ONE SPOTTER FROM HIGHLAND NY IN ULSTER CO REPORT PEA SIZE HAIL WITH ONE CELL. THIS AREA OF SHOWERS AND THUNDERSTORMS APPEARS TO BE IN ASSOCIATION WITH THE APPROACH OF AN OCCLUDED FRONT FROM THE WEST...AND ALSO AIDED BY THE PASSAGE OF AN UPPER LEVEL JET CORE OFF THE NORTHERN MID ATLANTIC COAST...PLACING OUR REGION WITHIN ITS LEFT EXIT REGION. A POTENT VORT LOBE CURRENTLY TRANSLATING EAST/NORTHEAST THROUGH THE LOWER OH AND TN VALLEYS WILL ROUND THE EAST SIDE OF THE UPPER LEVEL TROUGH AND APPROACH TOWARD DAYBREAK. THIS SHOULD ALLOW SHOWERS TO PERSIST THROUGH DAYBREAK...WITH PERHAPS A FEW PERIODS OF STEADY...MODERATE RAIN AT TIMES. TEMPS WILL HOLD NEARLY STEADY...OR PERHAPS RISE A BIT IN SOME AREAS BEFORE FALLING SEVERAL DEGREES AGAIN CLOSER TO DAYBREAK...WITH MAINLY 40S EXPECTED FOR LOWS. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/... DURING THE DAY ON TUESDAY WE CAN EXPECT SOME LINGERING SHOWERS DURING THE DAY WITH SOME BREAKS OF SUN POSSIBLE IN THE AFTERNOON. THE UPPER LEVEL TROUGH AXIS WILL BE PASSING THROUGH THE AREA WITH AN ASSOCIATED VORT MAX. HIGH TEMPS ON TUESDAY ARE EXPECTED MAX TEMPS ARE FORECAST TO REACH THE LOWER/MID 60S IN VALLEY AREAS AND 50S ACROSS HIGHER ELEVATIONS. FOR TUESDAY NIGHT AND WEDNESDAY...A SECONDARY TROUGH IS EXPECTED TO MOVE FROM THE MIDWEST THROUGH CENTRAL NEW YORK AND CENTRAL PENNSYLVANIA BRINGING ANOTHER ROUND OF SHOWERS AND THIS WILL BE FOLLOWED BY YET ANOTHER TROUGH OF LOW PRESSURE ON WEDNESDAY. THIS IS ALL OCCURRING AT THE SURFACE WHILE ALOFT AN UPPER LEVEL CLOSED LOW SITS AND SPINS JUST NORTH OF THE UPPER GREAT LAKES SENDING PIECES OF ENERGY IN THE FORM OF VORT LOBES ACROSS OUR FA DURING MUCH OF THE PERIOD. EXPECT LOWS ON TUESDAY NIGHT ARE EXPECTED TO RANGE FROM THE UPPER 20S NORTHWEST TO AROUND 40 SOUTHEAST. SOME LIGHT SNOW ACCUMULATIONS GENERALLY UNDER AN INCH ARE POSSIBLE ACROSS THE WESTERN ADIRONDACKS. HIGHS ON WEDNESDAY ARE EXPECTED TO RANGE FROM THE UPPER 40S NORTHWEST TO AROUND 690 NORTHWEST. FOR WEDNESDAY NIGHT AND THURSDAY NOT MUCH IMPROVEMENT IS EXPECTED AS THE UPPER LEVEL TROUGH AXIS SETTLES ACROSS THE NORTHEAST US WHILE AT THE SURFACE LOW PRESSURE INTENSIFIES ACROSS THE GULF OF MAINE WITH YET ANOTHER COLD FRONT EXPECTED TO MOVE INTO THE EASTERN GREAT LAKES BY THURSDAY. THUS THERE WILL STILL BE SCATTERED SHOWERS AROUND ALTHOUGH THE PCPN SHOULD BE MAINLY ON THE LIGHT SIDE. EXPECT LOWS WEDNESDAY NIGHT TO BE IN THE UPPER 20S TO UPPER 30S WITH ONCE AGAIN A LITTLE LIGHT SNOW POSSIBLE ACROSS THE WESTERN ADIRONDACKS WITH HIGHS ON THURSDAY IN THE MID 40S TO LOWER 50S. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... BELOW NORMAL TEMPERATURES ALONG WITH SOME INTERVALS OF RAIN AND EVEN SNOW SHOWERS ARE EXPECTED THROUGH THE WEEKEND. MODEL GUIDANCE REMAINS IN GOOD AGREEMENT INDICATING A LARGE SCALE UPPER LOW WILL DOMINATE OUR WEATHER. HOWEVER THERE CONTINUES TO BE SOME DISAGREEMENT ON ITS EXACT TRACK AND WITH THE TIMING OF INDIVIDUAL SHORT WAVE ROTATING ABOUT IT. THERE IS CONSENSUS THE CENTER OF THE UPPER LOW SHOULD REMAIN TO OUR NORTH AS IT MOVES ACROSS EASTERN CANADA KEEPING OUR THE REGION IN WESTERLY FLOW. HAVE FAVORED GUIDANCE FROM THE WEATHER PREDICTION CENTER TO MAINTAIN FORECAST CONSISTENCY. THE BETTER CHANCES FOR SCATTERED SHOWERS WILL BE ACROSS THE HIGHER TERRAIN. RAIN SHOWERS ARE EXPECTED DURING THE DAY...BUT AT NIGHT IT WILL BE COLD ENOUGH FOR SNOW SHOWER ESPECIALLY ACROSS THE HIGHER ELEVATIONS. OVERALL EXPECTING HIGHS IN THE 40S AND 50S WITH LOWS IN THE 20S AND 30S. NORMALS FOR LATE APRIL... ALBANY NY: HIGHS IN THE LOWER 60S AND LOWS IN THE LOWER 40S. GLENS FALLS NY: HIGHS IN THE LOWER 60S AND LOWS IN THE UPPER 30S. POUGHKEEPSIE NY: HIGHS IN THE MID 60S AND LOWS AROUND 40. BENNINGTON VT: HIGHS IN THE LOWER 60S AND LOWS IN THE UPPER 30S. PITTSFIELD MA: HIGHS IN THE UPPER 50S AND LOWS IN THE MID 30S. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... A LOW PRESSURE SYSTEM WILL OCCLUDE AS IT MOVES ACROSS THE REGION TONIGHT. WE HAVE HAD A BIT OF A LULL IN THE PRECIPITATION THIS EVENING. HAVE SHOWERS ACTIVITY OCCURRING TO EAST AND CONVECTION TO OUR WEST IN THE VICINITY OF THE WARM FRONT. THE HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON CONVECTION SO HAVE USED IT AS A GUIDE TO INCREASE POPS THIS EVENING WITH THE BEST CHANCES AS WE APPROACH MIDNIGHT AS ANOTHER DISTURBANCE AHEAD THE OCCLUDING FRONTAL BOUNDARY WILL INCREASE THE THREAT FOR CONVECTION. WE ARE NOT EXPECTED TO GET INTO THE WARM SECTOR IT GETS PINCHED OFF JUST TO THE SOUTH OF OUR FORECAST AREA TONIGHT AS THE SYSTEM OCCLUDES. THE MODELS CONTINUE TO SHOW SOME ELEVATED INSTABILITY WITH SHOWALTER INDICES BELOW ZERO MOVING ACROSS THE REGION TONIGHT...SO THERE IS A CHANCE FOR THUNDERSTORMS HOWEVER CONFIDENCE IS TOO LOW TO INCLUDE IN THE TAFS. CONDITIONS WILL LOWER WITH WIDESPREAD MVFR-IFR DEVELOPING. A GRADUAL IMPROVEMENT WILL OCCUR WITH THE PASSAGE OF THE OCCLUDED FRONT. WITH WIDESPREAD VFR FOR THE AFTERNOON. HAVE NORTHEAST TO SOUTHEAST FLOW ACROSS AREA. RECENT OBSERVATIONS SHOWN A DIMINISHING TREND IN WIND GUSTS ACROSS THE BERKSHIRES... TACONICS AND SOUTHERN VERMONT WHERE THE FLOW HAS BEEN ENHANCED BY THE TERRAIN. WINDS WILL LIGHTEN AS THE OCCLUDED BOUNDARY MOVES THOUGH WITH A SHIFT TO SOUTHWEST TO WEST WITH ITS PASSAGE. WESTERLY WINDS WILL INCREASE TO 10 TO 15 KNOTS AND WILL BE GUSTY ESPECIALLY AT KALB AND KPSF. OUTLOOK... TUE NIGHT-WED: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. WED NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN. THU: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. THU NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. FRI: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. SAT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. && .FIRE WEATHER... THERE ARE NO FIRE WEATHER CONCERNS THIS WEEK AS WE WILL BE UNDER THE INFLUENCE OF AN UPPER LEVEL TROUGH. A WIDESPREAD SOAKING RAINFALL WILL OCCUR ACROSS THE AREA THROUGH TONIGHT...WITH RAINFALL AMTS OF 0.75-1.5 INCHES EXPECTED. THE WEATHER WILL BE COOL AND UNSETTLED FOR MUCH OF THE WEEK. && .HYDROLOGY... A WIDESPREAD SOAKING RAINFALL WILL OCCUR ACROSS THROUGH TONIGHT. EXPECTING WIDESPREAD QPF AMOUNTS OF AROUND AN INCH WITH HIGHER AMOUNTS UP TO AROUND 1.5 INCHES WHERE THE RAINFALL IS ENHANCED BY THE STRONG EAST TO SOUTHEAST FLOW...PARTICULARLY ACROSS THE CENTRAL AND SOUTHEASTERN CATSKILLS...TACONICS...BERKSHIRES INTO THE LITCHFIELD HILLS AND ACROSS SOUTHERN VERMONT. LOCALIZED HIGHER AMOUNTS OF 2 TO 3 INCHES WILL BE POSSIBLE. THERE IS STILL SOME SNOW COVER LEFT IN THE FORECAST AREA. BASED ON NATIONAL OPERATIONAL HYDROLOGIC REMOTE SENSING CENTER (NOHRSC) THIS IS ACROSS THE PORTIONS OF THE WESTERN ADIRONDACKS AND ACROSS THE HIGHER TERRAIN OF THE SOUTHERN GREEN MOUNTAINS. BASED ON CURRENT FORECASTS...ONLY THE WEST CANADA CREEK AT HINCKLEY DAM IS EXPECTED TO EXCEED ITS FLOOD STAGE BY TUESDAY EVENING. THE REST OF THE WEEK THE FORECAST WILL BE DOMINATED BY A PERSISTENT UPPER LEVEL TROUGH WHICH WILL RESULT IN COOL TEMPERATURES...BREEZY CONDITIONS AND OCCASIONAL CHANCES FOR MAINLY LIGHT PRECIPITATION. FOR DETAILS ON SPECIFIC AREA RIVER 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...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...IAA/KL/LFM/11/WASULA NEAR TERM...IAA/KL/LFM/11/WASULA SHORT TERM...11 LONG TERM...IAA AVIATION...IAA/WASULA FIRE WEATHER...11 HYDROLOGY...IAA/KL/11
AREA FORECAST DISCUSSION
NWS LINCOLN IL
323 AM CDT TUE APR 21 2015 .SHORT TERM...(TODAY) ISSUED AT 323 AM CDT TUE APR 21 2015 WINDY CONDITIONS WILL ONCE AGAIN DEVELOP ACROSS CENTRAL ILLINOIS TODAY, THANKS TO A TIGHTENING PRESSURE GRADIENT AND DEEP-LAYER MIXING. THE STRONGEST WINDS WILL BE FOCUSED ALONG/NORTH OF THE I-74 CORRIDOR, WHERE FORECAST SOUNDINGS SUGGEST SUSTAINED WINDS OF AROUND 30MPH WITH GUSTS UP TO 40MPH AT TIMES. WILL THEREFORE ISSUE A WIND ADVISORY FOR THIS AREA FROM 11AM TO 7PM. FURTHER SOUTH ACROSS THE REMAINDER OF THE KILX CWA, WINDS WILL REMAIN BELOW ADVISORY CRITERIA, MAINLY IN THE 25 TO 30MPH RANGE. SKIES WILL BE MOSTLY SUNNY THROUGH MUCH OF THE DAY, WITH AN INCREASE IN CLOUDS NOTED ACROSS THE FAR SOUTH DURING THE AFTERNOON AS A MID-LEVEL SHORT-WAVE APPROACHES FROM THE WEST. ALL MODELS ARE DEVELOPING SCATTERED SHOWERS/THUNDER IN ADVANCE OF THIS WAVE, BUT PRIMARILY KEEP THE ACTIVITY JUST SOUTH OF THE CWA. HIGHER-RES MODELS SUCH AS THE HRRR ARE SLIGHTLY FURTHER NORTH, SO HAVE OPTED TO INCLUDE SLIGHT CHANCE POPS FOR SHOWERS SOUTH OF I-70 THIS AFTERNOON. THANKS TO INCREASED SUNSHINE, HIGH TEMPERATURES WILL BE A FEW DEGREES WARMER THAN YESTERDAY, WITH READINGS CLIMBING INTO THE LOWER TO MIDDLE 60S. && .LONG TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 323 AM CDT TUE APR 21 2015 MAIN CHALLENGES IN THE EXTENDED CONTINUE TO BE FROST POTENTIAL WEDNESDAY/THURSDAY NIGHTS, AS WELL AS, TIMING OF NEXT PRECIP EVENT BY THE END OF THE WEEK. DEEP UPPER LOW CURRENTLY CENTERED OVER THE WESTERN GREAT LAKES WILL BE THE DOMINANT WEATHER FEATURE ACROSS THE MIDWEST FOR THE NEXT FEW DAYS, RESULTING IN COOL CONDITIONS THROUGH FRIDAY. AS A PIECE OF ENERGY ROTATES AROUND THE LOW, A WEAK COLD FRONT WILL DROP THROUGH ILLINOIS TONIGHT. FORECAST SOUNDINGS ARE INITIALLY QUITE DRY: HOWEVER, THE LATEST MODELS SHOW QUITE A BIT MORE TOP-DOWN MOISTENING THAN IN PREVIOUS RUNS. AS A RESULT, THINK SCATTERED LIGHT SHOWERS WILL ACCOMPANY THE FRONT TONIGHT, WITH PERHAPS A FEW SHOWERS LINGERING INTO WEDNESDAY MORNING ACROSS THE FAR SE. ONCE THE FRONT EXITS, CANADIAN HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE MIDDLE AND END OF THE WEEK. THE RIDGE AXIS IS PROGGED TO BE JUST WEST OF THE MISSISSIPPI RIVER BY 12Z THURSDAY, SO AM EXPECTING WINDS TO DIMINISH CONSIDERABLY AS THE PRESSURE GRADIENT WEAKENS. WITH CLEAR SKIES AND LIGHT WINDS, OVERNIGHT LOWS WILL DIP INTO THE LOWER TO MIDDLE 30S, LEADING TO FROST DEVELOPMENT ACROSS MUCH OF THE AREA. IF SKIES REMAIN CLEAR, ANOTHER POTENTIALLY FROSTY NIGHT WILL OCCUR THURSDAY NIGHT AS WELL. FURTHER OUT, MODELS ARE HAVING CONSIDERABLE DIFFICULTY PINNING DOWN THE END OF THE WEEK SYSTEM. SOLUTIONS HAVE BEEN FLIP-FLOPPING FROM RUN TO RUN, SO OVERALL FORECAST CONFIDENCE BEYOND THURSDAY REMAINS LOWS. THE 00Z APR 21 GFS HAS MADE A MAJOR SHIFT BACK TO A SOLUTION IT FEATURED A COUPLE OF DAYS AGO. MEANWHILE, BOTH THE ECMWF AND GEM SEEM TO BE HEADING IN THE OPPOSITE DIRECTION. GIVEN SO MUCH MODEL INCONSISTENCY, PREFER TO MAKE VERY FEW CHANGES TO THE EXTENDED. WITH CANADIAN HIGH PRESSURE INITIALLY IN PLACE ACROSS THE MIDWEST ON WEDNESDAY/THURSDAY, STILL THINK A SLOWER ARRIVAL OF THE NEXT STORM SYSTEM MAKES SENSE. AS A RESULT, HAVE KEPT FRIDAY DRY DESPITE WHAT THE ECMWF AND GEM ARE ADVERTISING. HAVE INTRODUCED POPS FRIDAY NIGHT INTO SATURDAY AS A SYSTEM OVER THE DESERT SOUTHWEST GETS KICKED EASTWARD. STILL QUITE A BIT OF UNCERTAINTY CONCERNING HOW FAR NORTH PRECIP WILL SPREAD, BUT HAVE STUCK WITH PREVIOUS THINKING OF KEEPING HIGHEST POPS FOCUSED ACROSS THE SOUTHERN HALF OF THE CWA. THIS IS IN GOOD AGREEMENT WITH THE LATEST GFS, BUT NOT THE ECMWF/GEM WHICH BOTH FOCUS PRECIP MUCH FURTHER NORTH. ONCE THE SYSTEM EXITS, A RETURN TO DRY WEATHER IS ANTICIPATED FOR SUNDAY BEFORE ANOTHER FAST-MOVING NORTHERN-STREAM WAVE POTENTIALLY BRINGS A FEW SHOWERS BACK INTO THE PICTURE BY MONDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1158 PM CDT MON APR 20 2015 WINDS UP OVERNIGHT, DRIVEN PARTIALLY BY A PRESSURE GRADIENT STILL IN PLACE IN THE WAKE OF THE EXITING LOW PRESSURE SYSTEM TO THE NORTH/NORTHEAST. WINDS REMAIN GUSTY TOMORROW, GUSTING IN EXCESS OF 30-35KTS THROUGH THE AFTERNOON WITH DAYTIME HEATING/MIXING. DIFFERING MOISTURE PROFILES PUT CU POTENTIAL AT 5KFT IN THE EAST AND HIGHER IN THE WEST...ALTHOUGH THE CU RULE IS ACTUALLY MINIMIZED IN A RIDGE THROUGH CENTRAL ILLINOIS. QUICK WAVE THROUGH THE REGION WILL BRING THREAT OF PRECIP BUT COVERAGE IS LIKELY TO BE SCATTERED AT THIS POINT AND MOSTLY NORTH AND SOUTH OF THE AREA...SO VCSH FOR BMI AND PIA IS ALL THAT IS MENTIONED IN THE TAFS FOR NOW. && .ILX WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 11 AM THIS MORNING TO 7 PM CDT THIS EVENING FOR ILZ027>031-037-038-043>046. && $$ SHORT TERM...BARNES LONG TERM...BARNES AVIATION...HJS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
556 AM EDT TUE APR 21 2015 .SYNOPSIS... ISSUED AT 356 AM EDT TUE APR 21 2015 STRONG WESTERLY WINDS ARE EXPECTED TODAY WITH GUSTS AS HIGH AS 45 MPH. THERE IS ALSO A SLIGHT CHANCE FOR A FEW AFTERNOON RAIN SHOWERS...MAINLY ALONG AND NORTH OF THE TOLL ROAD. HIGHS TODAY WILL BE IN THE MID 50S WITH LOWS TONIGHT IN THE MID 30S. COOL AND DRY CONDITIONS WILL THEN CONTINUE THROUGH THE REST OF THIS WEEK. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 356 AM EDT TUE APR 21 2015 STRONG WINDS WILL BE THE FORECAST MESSAGE OF THE DAY. STILL A DECENT HEIGHT/PRESSURE GRADIENT IN PLACE BETWEEN LARGELY BAROTROPIC LOW PRESSURE NEAR JAMES BAY AND ANTICYCLONE ACROSS THE GULF COAST. HOWEVER...THE REAL KEY FACTOR FOR GUSTY WINDS WILL BE VERY DEEP BOUNDARY LAYER MIXING. COMBINATION OF DRY AIR ADVECTION NEAR THE SURFACE...STRONG LATE APRIL SUN...AND VERY COLD CONDITIONS ALOFT WILL SET THE STAGE FOR MIXING HEIGHTS TO CLIMB TO AT LEAST 6 KFT WITH SOME MODELS (GFS AND RAP) SUGGESTING BOUNDARY LAYER DEPTHS WILL APPROACH 9 KFT. WIND SPEEDS AT THOSE LEVELS WILL BE IN THE 40-50 KT RANGE. NO DOUBT IT WILL BE WINDY BUT THE QUESTION IS WILL IT REACH ADVISORY CRITERIA (39KTS/45MPH). LACK OF GOOD ISENTROPIC DESCENT TO FORCE DOWN HIGHER MOMENTUM AIR IS CONCERNING...AS IS LACK OF ISALLOBARIC COMPONENT. ALWAYS SOME QUESTION AS TO HOW EFFICIENT TURBULENT MIXING ALONE WILL BE IN PRODUCING HIGHER GUSTS AT THE SURFACE....ESPECIALLY WHEN MIXING OVER SUCH A DEEP LAYER...AND NAM (AS WELL AS SOME OTHER HI-RES MODEL) SOUNDINGS ARE NOT QUITE AS BULLISH. THAT BEING SAID...MOST MODELS SHOW WIND SPEEDS AROUND 40 KTS AT THE TOP OF THE BOUNDARY LAYER AND SEVERAL INDICATE MIXING INTO SOME 50 KT WINDS. GIVEN THIS AND POTENTIAL FOR CONVECTIVE SHOWERS TO ENHANCE DOWNWARD MOMENTUM TRANSFER (SEE NEXT PARAGRAPH)...FEEL IT IS PRUDENT TO GO AHEAD AND PULL THE TRIGGER ON A WIND ADVISORY. EVEN IF MORE IMPRESSIVE GFS AND RAP FORECAST SOUNDINGS/WIND FIELDS DONT VERIFY...WILL STILL BE CLOSE TO ADVISORY CRITERIA. 500MB TEMPS BELOW -30C WILL SUPPORT A VERY DEEP LAYER OF STEEP LAPSE RATES DURING THE DAY TODAY. DEGREE OF MOISTURE AVAILABLE IS VERY MUCH IN QUESTION AND REMAINS A SIGNIFICANT LIMITING FACTOR FOR PRECIP DEVELOPMENT BUT SHREDS OF VORTICITY ROTATING AROUND LARGE CLOSED LOW COULD PROVIDE JUST ENOUGH MIDLEVEL CONVERGENCE/SATURATION TO WARRANT A FEW ISOLATED SPRINKLES/SHOWERS...MAINLY IN OUR NORTHERN COUNTIES. INHERITED FORECAST OF LOW CHANCE POPS ACROSS THE NORTH SEEMS REASONABLE. IF ANY SHOWERS DO MANAGE TO DEVELOP...STRONG NEGATIVE BUOYANCY DUE TO EVAPORATIONAL COOLING WITH "INVERTED V" SOUNDING COULD HELP MIX DOWN SOME HIGHER GUSTS. COULD ALSO BE SOME SMALL HAIL GIVEN COLD/DRY AIRMASS BUT VERY MARGINAL CAPE VALUES SUGGEST ANY SUBSTANTIVE UPDRAFTS WILL BE FEW AND FAR BETWEEN. SLIGHT CHANCE FOR SOME PRECIP LATE TONIGHT AS A MORE POTENT SHORTWAVE SWINGS THROUGH THE AREA. MOST MODELS KEEP LOW LEVEL FGEN RESPONSE JUST TO OUR SOUTH THOUGH AND WILL HOLD WITH A LOW CHANCE POP. DESPITE VERY COLD AIR ALOFT...TEMPS SHOULD RECOVER INTO THE MID 50S TODAY GIVEN DEEP MIXING. LOWS TONIGHT SHOULD GENERALLY HOLD IN THE MID 30S WITH STEADY WEST WINDS AND AT LEAST SOME CLOUDS KEEPING THE THREAT OF FROST LOW. && .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 356 AM EDT TUE APR 21 2015 NEG HGT ANOMALIES WILL PERSIST OVR SE CANADA THIS PD IN ASSOCN/W SLW EWD MEANDER OF DEEP CUTOFF FM THE LAKES THROUGH SE CANADA. THIS YIELDS A CONTN OF NW FLW ALOFT ACRS THE LAKES/OH VALLEY ALG W/MUCH BLO NORMAL TEMPS AND DRY WX THIS PD. HWVR POTENTIAL PITFALL EXISTS IN FRI NIGHT-SAT TIME FRAME W/BOTH HANDLING/PLACEMENT OF NWWD ORIENTED MID LVL TROUGH AXIS EXTENDING BACK INTO THE NRN PLAINS AND NEWD EJECTION OF SRN STREAM SW LOCATED OFF THE SRN CA COAST THIS MORNING. EC ELUCIDATED THIS POSSIBILITY FIRST LAST NIGHT AND NOW HAS GROWING SPRT FM GEM. THUS FELT IT PRUDENT TO PLACE SOME CONFIDENCE IN ALLBLEND GUIDANCE FOR THIS TIME PD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 556 AM EDT TUE APR 21 2015 DEEP MIXING AND TIGHT GRADIENT IN THE WAKE OF LOW PRESSURE OVER ONTARIO WILL LEAD TO STRONG WESTERLY WINDS TODAY. WIND SPEEDS AT THE TOP OF THE BOUNDARY LAYER ARE IN THE 40-50 KT RANGE SO EXPECT GUSTS UP TO AROUND 40 KTS FROM LATE MORNING THROUGH THE AFTERNOON. DRY AIR AND DEEP MIXING WILL HOWEVER KEEP CEILINGS ABOVE 5 KFT THROUGH THE PERIOD. SLIGHT CHANCE OF A SPRINKLE/SHOWER AT KSBN BUT NO IMPACT EXPECTED. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WIND ADVISORY FROM 11 AM EDT /10 AM CDT/ THIS MORNING TO 8 PM EDT /7 PM CDT/ THIS EVENING FOR INZ003>009-012>018-020- 022>027-032>034. MI...WIND ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR MIZ077>081. OH...WIND ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR OHZ001-002-004-005-015-016-024-025. LM...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR LMZ046. SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 4 PM EDT WEDNESDAY FOR LMZ046. GALE WARNING FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR LMZ046. SMALL CRAFT ADVISORY UNTIL 4 PM EDT WEDNESDAY FOR LMZ043. && $$ SYNOPSIS...AGD SHORT TERM...AGD LONG TERM...T AVIATION...AGD VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
356 AM EDT TUE APR 21 2015 .SYNOPSIS... ISSUED AT 356 AM EDT TUE APR 21 2015 STRONG WESTERLY WINDS ARE EXPECTED TODAY WITH GUSTS AS HIGH AS 45 MPH. THERE IS ALSO A SLIGHT CHANCE FOR A FEW AFTERNOON RAIN SHOWERS...MAINLY ALONG AND NORTH OF THE TOLL ROAD. HIGHS TODAY WILL BE IN THE MID 50S WITH LOWS TONIGHT IN THE MID 30S. COOL AND DRY CONDITIONS WILL THEN CONTINUE THROUGH THE REST OF THIS WEEK. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 356 AM EDT TUE APR 21 2015 STRONG WINDS WILL BE THE FORECAST MESSAGE OF THE DAY. STILL A DECENT HEIGHT/PRESSURE GRADIENT IN PLACE BETWEEN LARGELY BAROTROPIC LOW PRESSURE NEAR JAMES BAY AND ANTICYCLONE ACROSS THE GULF COAST. HOWEVER...THE REAL KEY FACTOR FOR GUSTY WINDS WILL BE VERY DEEP BOUNDARY LAYER MIXING. COMBINATION OF DRY AIR ADVECTION NEAR THE SURFACE...STRONG LATE APRIL SUN...AND VERY COLD CONDITIONS ALOFT WILL SET THE STAGE FOR MIXING HEIGHTS TO CLIMB TO AT LEAST 6 KFT WITH SOME MODELS (GFS AND RAP) SUGGESTING BOUNDARY LAYER DEPTHS WILL APPROACH 9 KFT. WIND SPEEDS AT THOSE LEVELS WILL BE IN THE 40-50 KT RANGE. NO DOUBT IT WILL BE WINDY BUT THE QUESTION IS WILL IT REACH ADVISORY CRITERIA (39KTS/45MPH). LACK OF GOOD ISENTROPIC DESCENT TO FORCE DOWN HIGHER MOMENTUM AIR IS CONCERNING...AS IS LACK OF ISALLOBARIC COMPONENT. ALWAYS SOME QUESTION AS TO HOW EFFICIENT TURBULENT MIXING ALONE WILL BE IN PRODUCING HIGHER GUSTS AT THE SURFACE....ESPECIALLY WHEN MIXING OVER SUCH A DEEP LAYER...AND NAM (AS WELL AS SOME OTHER HI-RES MODEL) SOUNDINGS ARE NOT QUITE AS BULLISH. THAT BEING SAID...MOST MODELS SHOW WIND SPEEDS AROUND 40 KTS AT THE TOP OF THE BOUNDARY LAYER AND SEVERAL INDICATE MIXING INTO SOME 50 KT WINDS. GIVEN THIS AND POTENTIAL FOR CONVECTIVE SHOWERS TO ENHANCE DOWNWARD MOMENTUM TRANSFER (SEE NEXT PARAGRAPH)...FEEL IT IS PRUDENT TO GO AHEAD AND PULL THE TRIGGER ON A WIND ADVISORY. EVEN IF MORE IMPRESSIVE GFS AND RAP FORECAST SOUNDINGS/WIND FIELDS DONT VERIFY...WILL STILL BE CLOSE TO ADVISORY CRITERIA. 500MB TEMPS BELOW -30C WILL SUPPORT A VERY DEEP LAYER OF STEEP LAPSE RATES DURING THE DAY TODAY. DEGREE OF MOISTURE AVAILABLE IS VERY MUCH IN QUESTION AND REMAINS A SIGNIFICANT LIMITING FACTOR FOR PRECIP DEVELOPMENT BUT SHREDS OF VORTICITY ROTATING AROUND LARGE CLOSED LOW COULD PROVIDE JUST ENOUGH MIDLEVEL CONVERGENCE/SATURATION TO WARRANT A FEW ISOLATED SPRINKLES/SHOWERS...MAINLY IN OUR NORTHERN COUNTIES. INHERITED FORECAST OF LOW CHANCE POPS ACROSS THE NORTH SEEMS REASONABLE. IF ANY SHOWERS DO MANAGE TO DEVELOP...STRONG NEGATIVE BUOYANCY DUE TO EVAPORATIONAL COOLING WITH "INVERTED V" SOUNDING COULD HELP MIX DOWN SOME HIGHER GUSTS. COULD ALSO BE SOME SMALL HAIL GIVEN COLD/DRY AIRMASS BUT VERY MARGINAL CAPE VALUES SUGGEST ANY SUBSTANTIVE UPDRAFTS WILL BE FEW AND FAR BETWEEN. SLIGHT CHANCE FOR SOME PRECIP LATE TONIGHT AS A MORE POTENT SHORTWAVE SWINGS THROUGH THE AREA. MOST MODELS KEEP LOW LEVEL FGEN RESPONSE JUST TO OUR SOUTH THOUGH AND WILL HOLD WITH A LOW CHANCE POP. DESPITE VERY COLD AIR ALOFT...TEMPS SHOULD RECOVER INTO THE MID 50S TODAY GIVEN DEEP MIXING. LOWS TONIGHT SHOULD GENERALLY HOLD IN THE MID 30S WITH STEADY WEST WINDS AND AT LEAST SOME CLOUDS KEEPING THE THREAT OF FROST LOW. && .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 356 AM EDT TUE APR 21 2015 NEG HGT ANOMALIES WILL PERSIST OVR SE CANADA THIS PD IN ASSOCN/W SLW EWD MEANDER OF DEEP CUTOFF FM THE LAKES THROUGH SE CANADA. THIS YIELDS A CONTN OF NW FLW ALOFT ACRS THE LAKES/OH VALLEY ALG W/MUCH BLO NORMAL TEMPS AND DRY WX THIS PD. HWVR POTENTIAL PITFALL EXISTS IN FRI NIGHT-SAT TIME FRAME W/BOTH HANDLING/PLACEMENT OF NWWD ORIENTED MID LVL TROUGH AXIS EXTENDING BACK INTO THE NRN PLAINS AND NEWD EJECTION OF SRN STREAM SW LOCATED OFF THE SRN CA COAST THIS MORNING. EC ELUCIDATED THIS POSSIBILITY FIRST LAST NIGHT AND NOW HAS GROWING SPRT FM GEM. THUS FELT IT PRUDENT TO PLACE SOME CONFIDENCE IN ALLBLEND GUIDANCE FOR THIS TIME PD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 130 AM EDT TUE APR 21 2015 LOW LEVEL DRY AIR ADVECTION IN THE WAKE OF LARGE CYCLONE OVER ONTARIO WILL ENSURE VFR CONDITIONS THROUGH THE PERIOD. MAIN IMPACT WILL BE VERY STRONG WESTERLY WINDS DURING THE DAY TODAY AS MIXING HEIGHTS CLIMB TO AROUND 7 KFT WHERE WIND SPEEDS ARE IN THE 40-45 KT RANGE. A FEW GUSTS TO AROUND 40 KTS ARE POSSIBLE DURING THE LATE MORNING AND EARLY AFTERNOON. ISOLATED SHOWERS/SPRINKLES ARE ALSO POSSIBLE AT TIMES TODAY BUT NO IMPACT ANTICIPATED. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WIND ADVISORY FROM 11 AM EDT /10 AM CDT/ THIS MORNING TO 8 PM EDT /7 PM CDT/ THIS EVENING FOR INZ003>009-012>018-020- 022>027-032>034. MI...WIND ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR MIZ077>081. OH...WIND ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR OHZ001-002-004-005-015-016-024-025. LM...SMALL CRAFT ADVISORY UNTIL 4 PM EDT WEDNESDAY FOR LMZ043-046. && $$ SYNOPSIS...AGD SHORT TERM...AGD LONG TERM...T AVIATION...AGD VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS TOPEKA KS
353 AM CDT Tue Apr 21 2015 .SHORT TERM...(Today and Tonight) Issued at 300 AM CDT TUE APR 21 2015 Deep upper low over the Great Lakes was making slow eastward progress early this morning with likely a few small scale waves rotating around it through the Northern and Central Plains. Periodic mid cloud was present over the local area via isentropic upglide from rather brisk and backed mid level winds. At least minor amounts of EPV along the moist layer allowing some showers to form aloft, with weak returns on radar showing some very light precip reaching to the lower troposphere. HRRR and RAP runs quite similar to some 4km WRF runs with light precip forming over central Kansas in the next few hours, with latest IR imagery indicating recent cloud development there. All nearby 0Z soundings measured 850mb dewpoint depressions around 12C, making measurable amounts hard to imagine in this activity. A somewhat more unstable airmass develops over the southeast quarter of Kansas this afternoon with weak surface convergence. Will maintain small storm chances with still minor isentropic lift and weak wave potential in place. The stronger wind fields aloft could lead to some storm organization along with CAPE around 500 J/kg and dry adiabatic low level lapse rates to produce a very small threat for severe wind and hail in the mid afternoon to early evening. Areas outside of storms could also see a few rather strong wind gusts with mixing depths reaching 7000-10000ft AGL though some veering remains through the column. The still dry airmass and gusty winds lead to elevated fire danger in western locations this afternoon. Cold front via a stronger wave rotating around the low arrives this evening and makes quick south progress through the state tonight. Moisture, though modest, will continue to pool ahead of this front for some storm chances through much of the night in the southern zones, with typical diurnal trends allowing severe concerns to diminish. Models are allowing the boundary layer to decouple fairly quickly behind the front, but am somewhat skeptical of this given the baroclinic zone they advertise. If winds can fall quicker than expected, fairly clear skies could present a frost concern, but even if they do the window of cold and calm conditions for formation should be rather limited. Will mention patchy frost in far north where concern is highest. .LONG TERM...(Wednesday through Monday) Issued at 300 AM CDT TUE APR 21 2015 Eastern Kansas remains on the southwest side of an upper surface high for Wednesday, keeping high temperatures around 60 for most of the area. Have kept rain chances out of the southern areas with better chances south. Dry conditions continue Wednesday night into Thursday, with lows in the upper 30s to near 40 and highs climbing toward the middle 60s Thursday. Upper pattern starts to shift Thursday night as shortwave ridge noses out of the southern plains into our area, ahead of an upper trof lifting northeast out of the four corners region. Initial sensible weather impacts should be warmer lows in the 40s near 50 Thursday night with some showers possible after midnight as low level jet makes a return over the area. Latest EC appears to be trending toward the GFS solution for this shortwave as it moves into the plains, taking a faster track and developing the warm front from the surface low out into eastern or southeast Kansas. GFS keeps the boundary south of the area and would make for cloudy cool and rainy conditions area wide for Friday and Saturday night, and with EC solutions also trending this way, have gone with forecast as such. Southern branch of the upper jet takes the shortwave trof east of the area rather quickly on Saturday, with rain ending sometime during the morning hours. Cooler high pressure once again noses into the area behind the departing low and holds temperatures in the low 60s, followed by overnight lows in the 40s. Highs on Sunday rise a bit more into the middle 60s, and have kept rain chances relegated to north and west while surface high continues over the east. Another front progged to move across the area Sunday night with northwest flow aloft returning on Monday. Current forecast is for highs near 70, but this will depend on how strong the front and wave are as to how much cooler air it does, or does not, bring southward. && .AVIATION...(For the 06Z TAFs through 06Z Tuesday Night) Issued at 1123 PM CDT MON APR 20 2015 VFR prevails through period while weak passing systems bring sct to bkn mid level clouds. Westerly winds gust near 20 kts in the afternoon while sct thunderstorms that develop should remain south of the terminals. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...65 LONG TERM...67 AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS GRAY ME
1219 AM EDT TUE APR 21 2015 .SYNOPSIS... LOW PRESSURE MEANDERING NORTH OF THE GREAT LAKES WILL DRIVE A COLD FRONT TOWARD THE REGION TONIGHT. THE FRONT WILL SLOWLY CROSS THE REGION ON TUESDAY. LOW PRESSURE NORTH OF THE GREAT LAKES WILL GRADUALLY WEAKEN AS IT DRIFTS SOUTHEAST INTO NEW ENGLAND WEDNESDAY THROUGH THURSDAY. LOW PRESSURE WILL CONTINUE TO WEAKEN AS IT MEANDERS NORTH OF NEW ENGLAND FRIDAY THROUGH SATURDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 1215 AM...MINOR ESTF UPDATE TO REFLECT CURRENT RADAR TRENDS AND TO INGEST THE 04Z MESONET INTO 1ST PERIOD GRIDS. PREV DISC... UPDATE...THE HIGHEST THREAT FOR STRONG WIND GUSTS IS COMING TO AN END...SO WILL TAKE DOWN THE WIND ADVISORY. OTHERWISE NO MAJOR CHANGES TO THE FORECAST. MESOSCALE MODELS STILL FAVOR THE IDEA OF A COMPLEX OF TSTMS CROSSING THE FORECAST AREA DURING THE MORNING. SO NO CHANGES THERE EITHER. HAVE MODIFIED THE GRIDS THRU MORNING BASED ON LATEST HI-RES MODEL GUIDANCE. EXAMINING RECENT HRRR RUNS HAVE A LARGE AREA FAVORABLE FOR LIGHTNING DEVELOPMENT MOVING ACROSS THE REGION ON THE LEADING EDGE OF THE DRY SLOT NEAR MORNING. IN ADDITION...THE SPC SSEO PRODUCTS ALSO FAVOR A CLUSTER OR LINE OF TSTMS CROSSING THE FORECAST AREA NEAR 12Z. HAVE INCREASED THE PROBABILITY FOR THUNDER LATE TONIGHT AND EARLY TUE AS A RESULT. HAVE ALSO INTRODUCED SOME AREAS OF HEAVY RA TO THE GRIDS NEAR THE COASTAL FRONT AS WELL AS IN THE EAST SLOPES OF THE MTNS WHERE STRONG SELY LLJ WILL IMPINGE UPON THE TERRAIN. THIS LLJ...WHICH IS REALLY JUST GETTING UNDERWAY OVER SRN NEW ENGLAND PER KBOX 88D...WILL SLOWLY TRAVERSE THE COAST THRU ABOUT 06Z. THIS PUTS HEAVIEST PRECIP IN THE FORECAST AREA BETWEEN ABOUT 00Z AND 06Z. IN ADDITION TO THE HEAVY PRECIP...THIS LLJ MAY INDUCE SOME STRONG DOWNSLOPE WIND GUSTS NW OF THE WHITE MTNS. PREVIOUS DISCUSSION...THE FIRST BATCH OF RAIN FROM THIS MORNING WAS MOVING INTO EASTERN MAINE AS A WARM FRONT LIFTED NORTH INTO SOUTHERN CANADA. SO FAR ONLY A TENTH TO ABOUT A THIRD OF AN INCH OF RAIN HAS FALLEN TODAY WITH SOME ISOLATED HIGHER AMOUNTS. THIS MORNINGS GYX SOUNDING HAD PLENTY OF DRY AIR AND THIS INHIBITED RAINFALL FROM SPREADING FASTER FOR THE FIRST HALF OF THE DAY. STEADIER RAINS ARE NOW OVER SOUTHERN NH AND MOVING INTO WESTERN MAINE. THIS TREND WILL CONTINUE INTO THE EVENING HOURS. A SECONDARY CYCLONE WILL FORM TONIGHT OVER THE VIRGINIAS AND MOVE NE ALONG THE ATLANTIC COAST. AS IT DEEPENS IN THE GULF OF MAINE A LLJ WILL STRENGTHEN AND FEED MOISTURE RICH AIR INTO COASTAL NH AND MAINE. WARM RAIN PROCESSES AND TRAINING OF CELLS WILL SUPPORT HEAVY RAIN OVERNIGHT AND INTO TUESDAY. A FLOOD WATCH REMAINS IN EFFECT AS RAIN COMBINES WITH SNOWMELT TO BRING RIVERS AND STREAMS TO NEAR BANKFULL. WINDS WILL BE GUSTY... ESPECIALLY ALONG THE COAST... BUT WE SHOULD FALL SHORT OF WIND ADVISORY CRITERIA. COASTAL FLOODING WILL ALSO BE A CONCERN FROM PORTLAND WESTWARD AS EASTERLY FLOW INCREASES AND COINCIDES WITH THE ASTRONOMICAL HIGH TIDE. MORE INFORMATION ON THESE HAZARDS BELOW. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 AM WEDNESDAY/... MODERATE TO HEAVY RAIN CONTINUES INTO TUESDAY MORNING. MUCAPE VALUES INDICATE A SLIGHT CHANCE FOR THUNDERSTORMS BETWEEN 12-18Z TOMORROW AS THE COLD CORE OF THE UPPER LOW SWINGS BY OVERHEAD. DRIER AIR PUNCHES IN FROM THE SW MIDDAY TUESDAY. SOME LINGERING SHOWERS WILL BE POSSIBLE OVER THE MOUNTAINS IN UPSLOPE FLOW. HIGHS SHOULD WARM INTO THE UPPER 40S NORTH TO LOWER 60S SOUTH. ADDITIONAL SHOWERS WILL BE POSSIBLE TUESDAY NIGHT WITH CYCLONIC FLOW ALOFT. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... BROAD UPPER LEVEL CLOSED LOW WILL KEEP WEATHER UNSETTLED IN THE NORTHEAST THROUGH THE WEEK AND INTO THE WEEKEND AS IT GRADUALLY SHIFTS EAST. EXPECT SEVERAL LOBES OF ENERGY TO ROTATE AROUND THIS SYSTEM AND INTO THE NORTHEAST. ANY MORNING SUN ON WEDNESDAY WILL QUICKLY GIVE WAY TO CLOUDS AND SHOWERS AS THE FIRST OF THESE DISTURBANCES SWINGS INTO THE REGION. EXPECT THESE SHOWERS TO PERSIST INTO WEDNESDAY NIGHT AS A WEAK SURFACE LOW SLOWLY CROSSES THE REGION. STEADIER PRECIP WILL COME TO AN END AS LOW PRESSURE LIFTS INTO THE MARITIMES ON THURSDAY. EXPECT CLOUDY SKIES AND SCATTERED SHOWERS THURSDAY THROUGH FRIDAY WITH HIGHS IN THE 40S TO LOWER 50S. SHOWER ACTIVITY WILL DIMINISH OVER THE WEEKEND BUT SKIES WILL REMAIN MOSTLY CLOUDY WITH RAIN OR SNOW SHOWERS POSSIBLE MAINLY IN NORTHERN ZONES. && .AVIATION /04Z TUESDAY THROUGH SATURDAY/... SHORT TERM...MVFR WILL DETERIORATE TO LIFR AND IFR SHORTLY AS HEAVIER RAIN MOVES IN. RAIN MAY BE LIGHTER AT KHIE WHERE WE WILL SEE THE RAIN SHADOW EFFECT. ALSO SOME SNOW MAY MIX IN LATE IN THE NORTH. EAST WINDS MAY GUST TO 35 KTS AT TIMES. SOME IMPROVEMENT BY MID MORNING TUESDAY AS RAIN MOVES EAST. LONG TERM...AREAS OF MVFR CEILINGS WEDNESDAY THROUGH FRIDAY. && .MARINE... SHORT TERM...EASTERLY WINDS AND SEAS CONTINUE TO BUILD TONIGHT. A GALE WARNING REMAINS IN EFFECT THROUGH 2 PM TUESDAY. WINDS WILL DECREASE BUT A SCA WILL LIKELY BE NEEDED FOR WAVES THROUGH WEDNESDAY EVENING. LONG TERM...SCA`S MAY BE NEEDED THURSDAY AND FRIDAY. && .FIRE WEATHER... ONSHORE FLOW TODAY BRINGS MORE MOISTURE AND EVENTUALLY RAIN TO THE AREA. A SOAKING RAIN IS EXPECTED LATE TODAY AND TUESDAY. && .HYDROLOGY... A WIDESPREAD 1 TO 2 INCHES OF RAIN IS EXPECTED FROM THIS AFTERNOON THROUGH TUESDAY. HOWEVER...GIVEN STRONG MOISTURE INFLOW...LOCALIZED AMOUNTS OF UP TO 3 INCHES COULD OCCUR. THIS WOULD LEAD TO FLOODING PROBLEMS...ESPECIALLY IN AREAS WHERE SNOW MELT IS STILL OCCURRING. A FLOOD WATCH REMAINS IN EFFECT. && .TIDES/COASTAL FLOODING... AS EASTERLY WINDS CONTINUE TO INCREASE...SEAS WILL BUILD 10 TO 15 FT. HIGH TIDE ON APRIL 21 IS AT 1:21 AM WITH A PREDICTED HEIGHT OF 11.4 FT MLLW. HOWEVER...ONSHORE WINDS ARE EXPECTED TO RESULT IN A 1- 2 FT STORM SURGE. THE COMBINATION OF WIND, WAVES AND HIGH TIDE WILL RESULT IN OVERWASH AND POSSIBLE INUNDATION FOR THE BEACHES OF THE SOUTH COAST OF MAINE AND NEW HAMPSHIRE. FARTHER DOWNEAST THE EASTERLY WIND DIRECTION IS LESS FAVORABLE FOR ONSHORE INUNDATION. EVEN SO THE SIGNIFICANT WAVES MAY RESULT IN SOME COASTAL FLOODING AND A COASTAL FLOOD ADVISORY HAS BEEN POSTED THERE. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR MEZ007>009-012>014- 018>028. COASTAL FLOOD ADVISORY UNTIL 3 AM EDT EARLY THIS MORNING FOR MEZ025>028. COASTAL FLOOD WARNING UNTIL 3 AM EDT EARLY THIS MORNING FOR MEZ023-024. NH...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR NHZ002>015. COASTAL FLOOD WARNING UNTIL 3 AM EDT EARLY THIS MORNING FOR NHZ014. MARINE...GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ150>154. && $$ ES
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
122 AM EDT TUE APR 21 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 353 PM EDT MON APR 20 2015 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEPENING UPR TROF OVER CENTRAL NAMERICA BTWN RDGS ALONG THE E AND W COASTS...WITH 12HR H5 HGT FALLS UP TO 150M NOTED OVER NRN WI IN ADVANCE OF SHRTWV LIFTING NWD INTO THE UPR LKS TO THE E OF THE UPR TROF AXIS. IR AND WV IMAGERY SHOW A WELL DEFINED COMMA HEAD CLD OVER THE UPR GREAT LKS IN ADVANCE OF SHRTWV AND ON CYC SIDE OF ACCOMPANYING H7 LO TRACK. STEADY RA UNDER THIS COMMA HEAD HAS MIXED WITH SN OVER THE WRN CWA WHERE DYNAMIC COOLING AND SOME LLVL CAA HAVE COOLED THE COLUMN SUFFICIENTLY. FARTHER TO THE E...DRY SLOTTING ON THE ACYC SIDE OF H7 LO TRACK HAS TENDED TO DIMINISH THE PCPN COVERAGE/INTENSITY OVER THE FAR E. ANOTHER SHRTWV IS DIGGING SWD THRU FAR NW ONTARIO/MANITOBA ON THE WRN FLANK OF H5 CLOSED LO MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON POPS/PTYPE ASSOCIATED WITH SHRTWV MOVING THRU THE UPR LKS RIGHT NOW AND THEN TNGT/TMRW ACCOMPANYING PASSAGE OF NEXT SHRTWV AND WITHIN LINGERING DEEP CYC FLOW UNDER CUTOFF H5 LO PROGGED TO LINGER OVER THE UPR LKS. LATE TDAY/TNGT...AS SHRTWV E OF THE UPR TROF AXIS LIFTS TO THE N THRU THIS AFTN AND TENDS TO SHEAR OUT...MODELS SHOW AREA OF SHARP DEEP LYR QVECTOR CNVGC SUPPORTING AXIS OF COLDER CLD TOPS DIMINISHING AND GIVING WAY TO SOME DEEP LYR QVECTOR DVGC. SO AREA OF STEADY RA/SN OVER THE W SHOULD DIMINISH BY LATE AFTN WITH ARRIVAL OF THE NEGATIVE DYNAMICS/MID LVL DRYING. POPS OVER THE E WL TEND TO INCREASE LATE THIS AFTN/EARLY EVNG AS COMMA TAIL AXIS OF HIER RH SWINGS E THRU THAT AREA...BUT PCPN INTENSITY WL NOT BE AS GREAT AS OVER THE W SINCE THE SUPPORTING AXIS OF DIMINISHING DEEP LYR QVECTOR CNVGC IS FCST TO REMAIN OVER THE W. NOT OUT OF THE QUESTION THERE COULD BE A FEW INCHES OF WET SN ACCUM OVER THE HIER TERRAIN OF THE W...BUT THERE SHOULD BE LTL IF ANY SN OVER THE E HALF WITH WEAKER DYNAMIC FORCING/COOLING. LATER TNGT...THE TRAILING SHRTWV DIGGING SWD TOWARD NW MN ON THE WRN FLANK OF CLOSED H5 LO IS FCST TO DIG TO NEAR NW WI BY 12Z TUE...BRINGING SOME DPVA/MORE DEEP LYR QVECTOR CNVGC TO THE W LATER TNGT. SHARP CYC UPSLOPE WNW FLOW IN THE PRESENCE OF THE DEEPER FORCING/MSTR WL SUPPORT LIKELY POPS IN THIS AREA. THERE COULD BE A FEW INCHES OF WET SN ACCUM OVER MAINLY THE HIER TERRAIN. OVER THE CENTRAL AND E...THERE WL BE ONLY ISOLD-SCT RA AND SN SHOWERS. TUE...SHRTWV/ACCOMPANYING SFC LO PRES TROF ROTATING ARND CLOSED H5 LO SHIFTING SLOWLY TO THE E OVER LK SUP IS FCST TO WEAKEN SLOWLY... LEADING TO SLOWLY DIMINISHING DEEP LYR QVECTOR CNVGC. ALTHOUGH THESE TRENDS WL RESULT IN DIMINISHING POPS...DAYTIME HEATING/LLVL DESTABILIZATION WL ENHANCE POPS ESPECIALLY OVER THE ERN CWA IN THE AFTN...WHERE LLVL CNVGC WITHIN LO PRES TROF WL BE ENHANCED BY LK BREEZE DEVELOPMENT. OTRW...LINGERING SHARP LLVL CNVGC AND THE DAYTIME HEATING WL MAINTAIN AT LEAST CHC POPS. THE PCPN SHOULD BE MAINLY SN IN THE MRNG...BUT THIS PCPN WL MIX WITH/CHG TO RA OVER THE SE HALF IN THE AFTN WITH DAYTIME HEATING/TEMPS RISING AOA 40. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 338 PM EDT MON APR 20 2015 A LARGE UPPER LOW CENTERED OVER NORTHERN ONTARIO WILL BE INFLUENCING THE GREAT LAKES REGION THROUGH THE FIRST HALF OF THE LONG TERM PERIOD. THIS WILL LEAD TO BELOW NORMAL TEMPERATURES AND PERIODS OF SNOW BEFORE GRADUALLY SHIFTING EAST INTO THE ATLANTIC BY THE WEEKEND. AS THAT UPPER LOW SPINS BETWEEN LAKE SUPERIOR AND JAMES BAY...IT WILL ROTATE SEVERAL SHORTWAVES ACROSS THE UPPER GREAT LAKES REGION TUESDAY NIGHT THROUGH THURSDAY. THESE WAVES WILL BRING PERIODS OF SHOWERS TO THE AREA...WITH HELP FROM BOTH LAKE SUPERIOR (850MB TEMPS FALLING TO -10C TO -12C ON WEDNESDAY MORNING) AND TERRAIN ENHANCEMENT (PERSISTENT LOW LEVEL NORTHWESTERLY FLOW). WILL CONTINUE TO FOCUS THE HIGHEST POPS (LIKELY VALUES) IN THOSE AREAS FAVORED BY ALL THREE FEATURES (HIGHER TERRAIN OF THE WEST/NORTHWEST) AND ALSO EAST DOWNWIND OF LAKE SUPERIOR...AND INCLUDE CHANCE/SLIGHTS FOR THE REST OF THE CWA. WITH THE AMOUNT OF COLD AIR IN PLACE...EXPECT THE PRECIPITATION TO FALL MAINLY AS SNOW. WITH LOW LEVEL TEMPERATURES WARMING AWAY OVER THE SOUTHERN THIRD OF THE CWA...COULD SEE SOME RAIN MIXING IN THERE...BUT OTHERWISE SNOW WILL BE THE NORM. COULD SEE A COUPLE INCHES OF ACCUMULATION IN THE FAVORED LOCATIONS TUESDAY NIGHT AND UP TO AN INCH WEDNESDAY AND AGAIN WEDNESDAY NIGHT. WITH DRIER AIR STARTING TO MOVE INTO THE AREA ON THURSDAY (ASSOCIATED WITH A SURFACE RIDGE MOVING INTO THE NORTHERN PLAINS...SHOULD SEE THE COVERAGE OF THE SHOWERS DIMINISHING THROUGH THE DAY THURSDAY AND CONTINUING TO WEAKENING INTO FRIDAY. ALSO...DON/T EXPECT HIGHS TO RISE MUCH OUT OF THE LOW-MID 30S ON WED/THURS OVER THE NORTH HALF OF THE CWA...WITH SOME HIGHS AROUND 40 OVER THE SOUTH CENTRAL. WILL LIKELY BREAK THE RECORD LOW HIGH TEMPERATURE HERE AT OUR OFFICE ON WEDNESDAY (36 SET IN 1972). EXTENDED RANGE MODELS DIFFER ON HOW QUICKLY THE UPPER LOW DEPARTS THIS WEEKEND...BUT SHOULD STILL SEE ENOUGH INFLUENCE FROM THE SURFACE RIDGE MOVING INTO THE NORTHERN PLAINS TO KEEP MOST OF THE AREA DRY. WITH THE NORTHERLY FLOW OFF LAKE SUPERIOR...EXPECT TEMPERATURES TO REMAIN BELOW NORMAL BUT IN THE 40S TO AROUND 50. AS THE UPPER LOW RETROGRADES BACK OVER QUEBEC EARLY NEXT WEEK...COULD SEE THE UPPER GREAT LAKES REGION BEING AFFECTED BY THE WESTERN EDGE OF THE ENERGY ROTATING AROUND THE UPPER LOW AND LIKELY KEEPING BELOW NORMAL TEMPERATURES IN PLACE THROUGH THE END OF APRIL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 120 AM EDT TUE APR 21 2015 APPROACH OF ANOTHER DISTURBANCE/LOW PRES TROF OVERNIGHT WILL RESULT IN DETERIORATING CONDITIONS FROM MVFR TO IFR AT KIWD/KCMX AS -SHSN INCREASE AGAIN. NOT OUT OF THE QUESTION THAT SOME BRIEF PERIODS OF LIFR COULD OCCUR. DOWNSLOPE W TO SW WINDS AT KSAW WILL RESTRICT THE IMPACT THERE...SO MVFR CIGS SHOULD PREVAIL. AFTER THE DISTURBANCE EXITS TO THE E...EXPECT MVFR CONDITIONS TO RETURN TO KIWD/KCMX MID TO LATE MORNING. -SHSN WILL CONTINUE AT ALL TERMINALS TODAY...AND IT`S CERTAINLY POSSIBLE THAT BRIEF IFR VIS COULD OCCUR AT TIMES... ESPECIALLY AT KIWD/KSAW AS DAYTIME HEATING/INSTABILITY AID -SHSN INTENSITY. WINDS WILL GENERALLY REMAIN GUSTY...PARTICULARLY AT KCMX WHERE GUSTS OF 25-30KT SHOULD BE COMMON FOR MUCH OF THE FCST PERIOD. MVFR CONDITIONS WILL CONTINUE INTO THIS EVENING AT ALL TERMINALS. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 353 PM EDT MON APR 20 2015 SHARP PRES GRADIENT ON THE SW FLANK OF SLOW MOVING LO PRES IN ONTARIO WILL CAUSE W TO NW WINDS UP TO 25-30 KTS INTO THU. ALTHOUGH THERE COULD BE SOME GALE FORCE GUSTS AT TIMES...WIDESPREAD GALES ARE NOT EXPECTED. THE CLOSER APPROACH OF HI PRES LATER IN THE WEEK WILL RESULT IN NW WINDS DIMINISHING TO NO MORE THAN 20 KTS ON FRI AND SAT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...SRF AVIATION...ROLFSON MARINE...KC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
357 AM CDT TUE APR 21 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 355 AM CDT TUE APR 21 2015 AN ARCTIC COLD FRONT ACROSS NORTH DAKOTA WILL BACK INTO THE FCST AREA THIS AFTN PRODUCING SOME CLOUDINESS. THE FRONT WILL CONTINUE TO MOVE SOUTH AND WEST TONIGHT. BY 12Z WEDNESDAY A SMALL AREA OF HIGH PRESSURE HAS SETTLED OVER NCNTL NEB WHICH SHOULD PRODUCE LOWS IN THE 20S. BY THIS TIME...THE MODELS SUGGEST ANY CLOUD COVER WOULD LIE ACROSS THE PANHANDLE AND SOUTHWEST NEB WHICH WOULD HOLD UP LOWS IN THE LOWER 30S. HIGHS TODAY RISE INTO THE 60S AHEAD OF THE FRONT WITH 50S NORTH OF THE FRONT ALONG HIGHWAY 20. THE MIDLEVEL CLOUD COVER ACROSS CNTL/SERN NEB EARLY THIS MORNING IS ASSOCIATED WITH 700MB FRONTOGENESIS. THE RAP MOVES THESE CLOUDS SOUTHEAST AND THEN DROPS A SECOND BATCH OF CLOUDS INTO NRN NEB AS EARLY AS 15Z WHICH HANG AROUND MOST OF THE DAY AND THEN MOVE SOUTH AND WEST TONIGHT. THE RADAR RETURNS ACROSS NORTH DAKOTA MOVE EAST OF THE FCST AREA IN THE NAM MODEL WHILE THE HRRR SHOWS TOO MUCH DRY AIR IN THE LOWER LEVELS FOR ANYTHING MORE THAN SPRINKLES THIS AFTN AND TONIGHT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 355 AM CDT TUE APR 21 2015 SURFACE HIGH PRESSURE QUICKLY FOLLOWS THE COLD FRONT AND WILL SLIDE SOUTHEAST OF THE AREA EARLY IN THE DAY ON WEDNESDAY WITH SOUTHERLY WINDS DEVELOPING. DESPITE SOUTHERLY WINDS...COOL AIR ALOFT...850 TEMP FROM 3C EAST TO 8C WEST...AND EVEN WITH SUN AND GOOD MIXING...HIGHS IN THE UPPER 50S AND LOWER 60S. MEANWHILE AN UPPER LEVEL LOW LIFTS TOWARDS THE DESERT SW. MODELS ALSO SHOW A WEAK SYSTEM AHEAD OF THE MAIN LOW...PUSHING ACROSS THE SOUTHERN PLAINS. A SECOND WAVE EJECTS FROM THE MAIN LOW AND ARRIVES TO THE SOUTHERN/CENTRAL PLAINS WED NIGHT INTO THURSDAY. MARGINAL LIFT INTO SW NEB MAY RESULT IN A FEW LIGHT SHOWERS INITIALLY. A BETTER CHANCE ARRIVES LATER IN THE DAY ON THURSDAY AFTER WE GET SOME HEATING. MODELS INCREASE CAPES TO A FEW 100 J/KG AND LIFTED INDEX VALUES AROUND ZERO OR SLIGHTLY NEG. GENERALLY THING ACTIVITY WILL BE SOME SHOWERS AND A FEW RUMBLES OF THUNDER HERE OR THERE. BY FRIDAY THE MAIN LOW WILL BE CROSSING THE ROCKIES. MOISTURE CONTINUES TO INCREASE AHEAD OF THE LOW AND FRIDAY LOOKS TO SEE A WAVE OR TWO OF SHOWERS TO ROTATE THROUGH THE AREA. BETTER MOISTURE LIFT ASSOCIATED CLOSER TO THE LOW...WHICH FAVORS HIGHER POPS ACROSS SW NEB. A SECOND WAVE...CLIPPER...QUICKLY FOLLOWS FOR THE WEEKEND. SHOULD SEE A BRIEF BREAK IN THE ACTIVITY BEFORE THE SECOND WAVE ARRIVES...ALTHOUGH TIMING THE BREAK IS DIFFICULT DUE TO MODEL DIFFERENCES. FORECAST DOES RETAIN LOW POPS AND EXPECT THIS TO CHANGE IN THE COMING DAYS AS THE LULL IN ACTIVITY BECOMES MORE CLEAR. AT THIS TIME MODELS ARE IN FAVOR OF THE DRY PERIOD TO OCCUR SOMETIME SATURDAY...EARLIEST IS THE GEM/GFS...WHILE LATER IS FAVORED BY THE ECMWF. THE NEXT WAVE SHOULD BE EAST OF THE AREA TO START THE WORK WEEK DRY AND MILD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1130 PM CDT MON APR 20 2015 FOR THE REMAINDER OF TONIGHT...SCATTERED TO BROKEN CIGS OF AROUND 10000 FT AGL ARE POSSIBLE THROUGH 12Z TUESDAY MORNING WITH CLEARING THEREAFTER. SCATTERED CIGS AROUND 9000 TO 10000 FT AGL ARE POSSIBLE DURING THE AFTERNOON HOURS WITH CLEARING EXPECTED TUESDAY EVENING. WINDS WILL BE LIGHT AND VARIABLE AT UNDER 10 KTS THROUGH MID MORNING...BECOMING WEST AND INCREASING TO 10 TO 20 KTS AROUND MIDDAY TUESDAY. SOME GUSTS TO 25 KTS ARE POSSIBLE DURING THE LATE AFTERNOON HOURS. WINDS WILL SHIFT TO THE NORTH AROUND 00Z WEDNESDAY AND WILL BE IN THE 10 TO 15 KT RANGE THROUGH 06Z WEDS. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...CLB
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
415 AM EDT TUE APR 21 2015 .SYNOPSIS... A STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL BRING VERY WINDY CONDITIONS TODAY...ALONG WITH A CHANCE OF SHOWERS AT TIMES THROUGH WEDNESDAY MORNING. DRIER CONDITIONS ARE EXPECTED FROM WEDNESDAY AFTERNOON THROUGH THE REST OF THE WEEK...WITH BREEZY AFTERNOONS AND COOL TEMPERATURES. ANOTHER CHANCE OF RAIN WILL ARRIVE ON SATURDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SCATTERED TO BROKEN CLOUDS IN THE 6KFT-10KFT LAYER ARE CROSSING THE ILN CWA FROM WEST TO EAST...DELINEATED VERY NICELY ON IR SATELLITE. WITHIN THESE PATCHES OF CLOUDS ARE SOME CONVECTIVE-LOOKING SHOWERS...AND ALTHOUGH NO LIGHTNING HAS BEEN OBSERVED...PEA SIZE HAIL WAS OBSERVED WITH ONE OF THE SHOWERS (THANKS TO THE FREEZING LEVELS OF AROUND 4KFT). THE PRIMARY CONCERN TODAY REMAINS THE THREAT FOR STRONG WINDS...AND AN ANALYSIS OF 00Z MODEL DATA SUPPORTED MAINTAINING THE CURRENT ORIENTATION FOR THE WIND ADVISORY (WITH A SPECIAL WEATHER STATEMENT FOR THE REST OF THE FORECAST AREA). STRONG UNIDIRECTIONAL FLOW (AT ABOUT 250 DEGREES) EXTENDS THROUGH THE ENTIRE DEPTH OF THE TROPOSPHERE...WITH VALUES STEADILY INCREASING OFF THE SURFACE. USING A RECENT RAP RUN AT KDAY ON BUFKIT AS AN EXAMPLE (AT 18Z)...WINDS INCREASE TO 40 KNOTS AT 825MB...THEN 50 KNOTS AT 700MB...AND 60 KNOTS AT 600MB. TODAY WILL BE AN EXERCISE IN MIXING...AS THE EVENTUAL DEPTH OF THE MIXED LAYER WILL LIKELY DETERMINE JUST HOW STRONG THE WINDS GET. GUSTS IN THIS FORECAST WERE GENERALLY GLEANED FROM BUFKIT MOMENTUM TRANSFER VIA RAP/GFS FORECASTS...WITH VALUES IN THE LOWER 40 KNOT RANGE IN THE NORTHERN CWA...AND LOWER 30 KNOT RANGE IN THE SOUTHERN CWA. ALTHOUGH CLEAR SKIES WILL BE IN PLACE AT THE BEGINNING OF THE DAY...WEAK ELEVATED FORCING AND A SLIGHT INCREASE IN MOISTURE AT THE TOP OF THE (RATHER HIGH) MIXED LAYER WILL RESULT IN SOME CLOUD DEVELOPMENT...AND EVENTUALLY SHOWERS IN THE SOUTHEASTERN HALF OF THE FORECAST AREA. THESE SHOWERS MAY BE VERY HIGH-BASED (PERHAPS 8000 FEET)...WITH SCATTERED COVERAGE AT MOST. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... PRECIPITATION IS EXPECTED TO MOVE INTO THE REGION (OR PERHAPS DEVELOP OVER THE FORECAST AREA) ON TUESDAY NIGHT INTO WEDNESDAY MORNING. ALTHOUGH THERE ARE SOME MODEL DIFFERENCES WITH REGARDS TO THE INTENSITY AND LAYOUT OF THE PRECIPITATION...THE OVERALL TIMING APPEARS TO FAVOR THE 06Z-15Z TIME FRAME FOR THE ILN FORECAST AREA...AHEAD OF A SHORTWAVE AND A SURFACE COLD FRONT. ALTHOUGH THIS FRONT SHOWS UP NICELY ON MSLP PLOTS...THE WIND SHIFT AND CHANGE IN AIR MASS ARE NOT ESPECIALLY NOTABLE. INSTABILITY (EVEN ELEVATED) WILL BE HARD TO COME BY...SO THOUGH THUNDER IS NOT AN IMPOSSIBILITY WITH THIS SETUP...THE CHANCE SEEMS VERY LOW. ONCE THIS FRONT PASSES...VERY SIMILAR CONDITIONS ARE EXPECTED FOR THE REST OF THE WEEK...WITH NORTHWEST FLOW AND COOL WEATHER. OHIO IS LIKELY TO REMAIN IN BETWEEN AREAS OF ENHANCED MOISTURE FROM THE NORTHERN AND SOUTHERN STREAMS...LEADING TO GENERALLY SUNNY CONDITIONS UNTIL FRIDAY NIGHT. TEMPERATURES ON THURSDAY AND FRIDAY MORNING MAY BE COOL ENOUGH FOR FROST...BUT MOISTURE AND WIND FORECASTS ARE NOT AS FAVORABLE. THUS...FROST WILL NOT BE INCLUDED IN THE GRIDS OR HWO. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... SOME DEEPER MOISTURE WILL BE PULLED UP TOWARD OUR AREA ON SATURDAY AHEAD OF SHORT WAVE ENERGY MOVING OUT OF THE ROCKIES. WHILE THE BEST FORCING/MOISTURE ASSOCIATED WITH THIS WILL REMAIN TO OUR SOUTH...SOME PCPN COULD SNEAK UP INTO AT LEAST SOUTHERN PORTIONS OF OUR FA EARLY IN THE WEEKEND. THIS MAY ALSO ALLOW FOR A SLIGHT MODIFICATION IN TEMPERATURES WITH HIGHS PUSHING INTO THE UPPER 50S TO LOWER 60S BY THE END OF THE LONG TERM PERIOD. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... LARGE SCALE UPPER LEVEL LOW CENTERED OVER THE WESTERN GREAT LAKES THIS MORNING WILL MOVE SLOWLY EAST THROUGH THE TAF PERIOD. EMBEDDED DISTURBANCES ROTATING AROUND THE LOW WILL AFFECT OUR REGION FROM TIME TO TIME. FOR EARLY THIS MORNING...THERE WILL BE A LULL IN SIGNIFICANT WEATHER ACTIVITY. MID CLOUDS CURRENTLY OVER THE REGION WILL PUSH OFF TO THE EAST...LEAVING MOSTLY CLEAR CONDITIONS BY 12Z. FOR TODAY...STRONG SURFACE LOW PRESSURE WILL REMAIN NORTH OF THE GREAT LAKES. MEANWHILE...A COLD FRONT WILL APPROACH THE REGION FROM THE WEST. THE INCREASING SURFACE PRESSURE GRADIENT COMBINED WITH DEEP MIXING WILL RESULT IN WINDY CONDITIONS FROM MID MORNING INTO EARLY EVENING. WINDS WILL VEER FROM A SOUTHWEST TO A WEST/SOUTHWEST DIRECTION WITH WIND GUSTS IN THE 30 TO 40 KNOT RANGE. MODELS CONTINUE TO INDICATE THAT SOME MOISTURE IN THE LOW TO MID LEVEL WILL DEVELOP/ADVECT NORTHEAST INTO THE REGION BY THIS AFTERNOON. THIS CLOUD LAYER COULD BECOME CONVECTIVE ENOUGH TO PRODUCE A FEW SPRINKLES OR LIGHT SHOWERS...MAINLY ALONG AND SOUTH OF THE OHIO RIVER. FOR TONIGHT...ONE OF THOSE EMBEDDED DISTURBANCES WILL DIG SOUTHEAST INTO OUR AREA. THIS FEATURE WILL TEAM UP WITH FRONTAL CONVERGENCE FROM THE ADVANCING COLD FRONT TO BRING A THREAT OF SHOWERS TO THE TAF SITES BETWEEN 06Z AND 12Z. THERE COULD BE SOME POCKETS OF MVFR VISIBILITIES ASSOCIATED WITH THE MORE ROBUST SHOWERS. OUTLOOK...GUSTY WEST TO NORTHWEST WINDS UP TO 30 KNOTS EXPECTED WEDNESDAY AFTERNOON INTO EARLY EVENING. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...WIND ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR OHZ026-034-035-042>046-051>056-060>062. KY...NONE. IN...WIND ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR INZ050. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...JGL AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS NORMAN OK
358 AM CDT TUE APR 21 2015 .DISCUSSION... THE FORECAST CHALLENGE OF THE DAY IS SEVERE WEATHER POTENTIAL THROUGH FRIDAY. THIS MORNING...ISOLATED TO SCATTERED SHOWERS FROM WEAK MID LEVEL MOISTURE CONVERGENCE/ISENTROPIC LIFT WILL CONTINUE MAINLY ACROSS SOUTHERN OKLAHOMA. CANNOT RULE OUT A RUMBLE OF THUNDER...BUT NO SEVERE WEATHER WILL OCCUR. ANY RAINFALL WILL BE LIGHT AND UNDER 0.10 INCH. THIS AFTERNOON...SKIES WILL CLEAR AND ALLOW FOR GOOD DAYTIME HEATING. THINK CAPPING WILL BE TOO STRONG FOR STORM DEVELOPMENT...EXCEPT PERHAPS NEAR A WEAK SURFACE BOUNDARY OVER SOUTHERN KANSAS ACCORDING TO THE LATEST HRRR RUN. KEPT 20 PERCENT CHANCE FOR STORMS NEAR THE KANSAS AND OKLAHOMA STATE LINE EAST OF ALVA AFTER 4 PM. IF THESE STORMS FORM...THEY COULD BE SEVERE WITH SOME LARGE HAIL UP TO GOLF BALLS AND DAMAGING WINDS UP TO 60 MPH AS STRONG 0-6 KM SHEAR AND MUCAPE AROUND 1000 J/KG SUPPORT SOME SEVERE POTENTIAL. TONIGHT...WILL MONITOR FOR ADDITIONAL STORM FORMATION...MAINLY AFTER MIDNIGHT ACROSS WESTERN OKLAHOMA ON THE NOSE OF THE LOW LEVEL JET. LATEST MODELS HAVE BEEN TRENDING SLOWER WITH STORM DEVELOPMENT. WITH INCREASING ELEVATED INSTABILITY AND STRONG 0-6 KM SHEAR...STORMS WILL BEGIN WITH LARGE HAIL UP TO GOLF BALLS AS THE MAIN HAZARD...BUT MAY TRANSITION TO SOME WIND AND HAIL AS STORMS MAY FORM INTO A CLUSTER OR LINE THEN MOVE EAST OR SOUTHEAST TOWARDS DAYBREAK...MAINLY AFFECTING WESTERN OKLAHOMA. A FEW ADDITIONAL SEVERE STORMS MAY BE NEAR A DEVELOPING COLD FRONT IN NORTHERN OKLAHOMA. WIDESPREAD SEVERE SEEMS UNLIKELY TONIGHT. WEDNESDAY...AN ACTIVE DAY OF SEVERE WEATHER MAY OCCUR... ESPECIALLY ACROSS THE SOUTHERN HALF OF OKLAHOMA AND NORTH TEXAS. A COMPLEX OF STORMS MAY OCCUR DURING THE MORNING HOURS AND MOVE EAST OR SOUTHEAST BRINGING SOME WIND AND HAIL REPORTS AS WELL AS LOCALLY HEAVY RAINFALL. REDEVELOPMENT MAY OCCUR DURING THE AFTERNOON AND EVENING NEAR THE OUTFLOW BOUNDARY WHICH MAY BE NEAR THE RED RIVER. THERE IS SOME POTENTIAL FOR SIGNFICANT SEVERE INCLUDING GIANT HAIL GREATER THAN GOLF BALLS...DAMAGING WINDS OVER 70 MPH...AND PERHAPS TORNADOES IF LOW LEVEL SHEAR IS STRONG ENOUGH...BUT CONFIDENCE OF THIS OCCURRING REMAINS LOW AS NOT SURE HOW THE CONVECTION DURING THE MORNING AFFECTS THE ENVIRONMENT DURING THE AFTERNOON AND EVENING HOURS. IT APPEARS NORTHERN OKLAHOMA MAY NOT RECEIVE MANY STORMS OR SEVERE WEATHER WHERE THE AIR WILL BE COOLER AND MORE STABLE. WEDNESDAY NIGHT INTO THURSDAY...A FEW SEVERE STORMS MAY LINGER OVER FAR SOUTHERN OKLAHOMA AND NORTH TEXAS WITH LARGE HAIL... DAMAGING WINDS...AND HEAVY RAINFALL. HOWEVER...MOST STORMS MAY BE SOUTH OF THE RED RIVER...LEAVING BEHIND COOL AND STABLE CONDITIONS ACROSS OKLAHOMA. CONFIDENCE OF SEVERE STORMS DURING THIS TIME FRAME REMAINS LOW AS NOT SURE HOW WEDNESDAY/S CONVECTION CHANGES THE AIRMASS ACROSS THE REGION. WENT BELOW MODEL GUIDANCE TEMPERATURES. FRIDAY...ANOTHER ROUND OF SEVERE THUNDERSTORMS...POSSIBLY WITH SIGNIFICANT SEVERE...MAY RETURN TO THE AREA. VERY STRONG SHEAR/WINDS WOULD SUPPORT FAST MOVING SUPERCELLS. HOWEVER... MOISTURE AND INSTABILITY REMAIN QUESTIONABLE...ESPECIALLY AS CONVECTION OVER TEXAS MAY LIMIT THE NORTHWARD PROGRESS OF RICHEST MOISTURE AND HIGHEST INSTABILITY. REGARDLESS...WILL CLOSELY MONITOR. ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS ALONG WITH WINDY AND HOT WEATHER MAY FORM BEHIND A DRYLINE. SATURDAY THROUGH MONDAY...A QUIETER WEATHER PATTERN IS FORECAST WITH NEAR AVERAGE TEMPERATURES. MBS && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 77 54 69 54 / 20 20 50 40 HOBART OK 77 54 73 54 / 10 40 70 40 WICHITA FALLS TX 78 57 76 57 / 10 20 40 40 GAGE OK 79 49 66 46 / 10 40 40 30 PONCA CITY OK 78 49 64 47 / 20 30 30 30 DURANT OK 76 57 75 60 / 30 10 60 40 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 25/17
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
442 AM CDT TUE APR 21 2015 .SHORT TERM (TODAY THROUGH WEDNESDAY)... A WEAK UPPER LEVEL DISTURBANCE MOVED OVER THE AREA OVERNIGHT AND CLEARING SKIES ARE LEFT IN ITS WAKE. THE CLEARING SHOULD BE TEMPORARY AS A MOIST LAYER AT 850 HPA SHOULD SATURATE IN MANY AREAS. THE CLOUDS WILL PROBABLY BE SCT VARIABLE TO BKN SINCE THE MOISTURE LAYER APPEARS THIN. THUS WILL GO WITH SLIGHTLY ABOVE BLENDED GUIDANCE HIGHS TODAY. RAP SOUNDINGS SUGGEST A BREAKABLE CAP SHOULD THERE BE ENOUGH MOISTURE SO WILL CONTINUE WITH ISOLATED POPS. AN UPPER LOW CURRENTLY OVER SOUTHERN CA WILL CONTINUE TO CARVE DEEPER OVER THE BAJA PENINSULA THROUGH WEDNESDAY. DEEPENING MOISTURE WILL LEAD TO INCREASED RAIN CHANCES AND A FEW STRONG STORMS AND POSSIBLE SUPERCELLS AS NOTED IN THE SPC DAY 2 OUTLOOK. && .LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)... A FAIRLY LIGHT LOW LEVEL FLOW WEDNESDAY NIGHT INTO THURSDAY MEANS THAT THERE COULD BE SOME REMNANT OUTFLOW BOUNDARIES LEFT FROM WEDNESDAY STORMS TO BRING ADDITIONAL STORM FOCUS FOR THURSDAY AS THE UPPER LOW BEGINS TO LIFT INTO THE SOUTHERN ROCKIES. HIGHEST POPS OF THE WEEK ARE THUS SAVED FOR THURSDAY NIGHT INTO FRIDAY. THE EJECTION OF THE LOW INTO A SHALLOW TROUGH LEAVES SOME COVERAGE UNCERTAINTIES THIS FAR SOUTH...SO DO NOT WANT TO OVER-ADVERTISE THE SEVERE THREAT BEYOND A NOD IN THE HWO. POPS SHOULD LOWER SATURDAY INTO SUNDAY AS FLAT RIDGING ALOFT RETURNS. MOISTURE IS SUFFICIENT FOR STORMS...BUT EXPECT A STRONGER CAPPING INVERSION. ANOTHER LOW LATITUDE UPPER DISTURBANCE IS FORECAST BY THE GFS TO BRING RAIN AND STORMS BY MIDWEEK...BUT WILL KEEP WITH THE MORE CONSERVATIVE ECMWF UNTIL THE PATTERN DIFFERENCES BETWEEN MODELS DECREASE. TEMPERATURES THROUGH THE PERIOD SHOULD CONTINUE TO BE SEASONAL. A WEAK FRONT EXPECTED SATURDAY WILL PROBABLY ADD TO DAYTIME TEMPERATURES THROUGH REDUCED CLOUDINESS. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 80 66 82 69 86 / 20 10 30 30 20 AUSTIN BERGSTROM INTL AIRPORT 79 66 81 68 85 / 20 10 30 30 20 NEW BRAUNFELS MUNI AIRPORT 79 66 82 69 87 / 20 20 30 30 20 BURNET MUNI AIRPORT 77 66 81 68 85 / 20 20 30 30 20 DEL RIO INTL AIRPORT 81 67 86 70 88 / 20 20 20 10 20 GEORGETOWN MUNI AIRPORT 79 67 82 68 86 / 20 10 30 30 20 HONDO MUNI AIRPORT 82 67 82 69 87 / 20 20 30 20 20 SAN MARCOS MUNI AIRPORT 78 66 81 68 85 / 20 20 30 30 20 LA GRANGE - FAYETTE REGIONAL 79 66 82 70 85 / 20 10 30 30 20 SAN ANTONIO INTL AIRPORT 80 68 82 71 86 / 20 20 30 20 20 STINSON MUNI AIRPORT 81 68 82 71 87 / 20 20 30 20 20 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...17 SYNOPTIC/GRIDS...18
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
410 AM EDT TUE APR 21 2015 .SYNOPSIS... A COLD FRONT WILL CONTINUE TO MOVE EAST THROUGH VIRGINIA AND WILL REACH THE COAST THIS MORNING. HIGH PRESSURE OVER THE SOUTHERN PLAINS WILL MOVE EAST TO THE COAST BY WEDNESDAY MORNING. ANOTHER FRONT WILL MOVE THROUGH THE AREA ON WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 400 AM EDT TUESDAY... LOCAL NATIONAL WEATHER SERVICE RADAR SHOWED WIDELY SCATTERED SHOWERS IN THE MOUNTAINS EARLY THIS MORNING. EVEN THOUGH UPSLOPE FLOW CONTINUES THROUGH THE DAY...HAVE ENDED THE SHOWERS AFTER THIS MORNING AND EXPECT A CLEARING SKY THIS AFTERNOON AS THE AIR MASS DRIES OUT. HRRR SUGGESTS SHOWERS MAY BE GONE AS EARLY AT 7AM. SURFACE DEW POINTS ALREADY DROPPING INTO THE 30S AND 40S BEHIND THE COLD FRONT THAT EXTENDED FROM EASTERN PENNSYLVANIA TO THE FLORIDA PANHANDLE. DRIER AIR ALOFT MAY BE SEEN ON THE WATER VAPOR LOOP ADVANCING ACROSS THE CENTRAL AND SOUTHERN APPALACHIANS. THE DOWNSLOPE WINDS WILL AIDE IN DRYING AND WARMING THE AIR EAST OF THE BLUE RIDGE. EXPECT HIGHS IN THE EAST TO BE ON THE WARMER SIDE OF GUIDANCE. BUFKIT FORECAST SOUNDINGS SHOWED DEEP MIXING WHICH WILL AIDE IN TRANSPORTING DRIER AIR DOWN TO THE SURFACE. THE DEEP MIXING AND PRESSURE RISES OF 3 TO 6 MB IN 6 HOURS WILL RESULT IN GUSTS AS HIGH AS 35 MPH. WINDS WILL DIMINISH TONIGHT AFTER SUNSET. LATER TONIGHT CLOUDS INCREASE AHEAD OF AN APPROACHING COLD FRONT. MODELS HOLD THE POTENTIAL FOR PRECIPITATION WEST OF THE FORECAST AREA UNTIL AFTER 07Z/3AM. LOW LEVEL JET FROM THE SOUTH-SOUTHWEST ALSO INCREASES TO NEARLY 45 KNOTS BY LATE TONIGHT. HAVE STRONG GUSTS...BUT STILL UNDER ADVISORY CRITERIA...AT HIGHER ELEVATIONS AFTER MIDNIGHT. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 330 AM EDT TUESDAY... THE CLOSED UPPER LOW WILL CONTINUE TO DO A SIT AND SPIN OVER THE GREAT LAKES REGION THROUGH THE SHORT TERM PERIOD....KEEPING OUR TEMPERATURES AT OR SLIGHTLY BELOW NORMAL. BY WEDNESDAY MORNING A SPOKE OF ENERGY ROTATING AROUND THE UPPER LOW WILL BE PUSHING A COLD FRONT INTO THE AREA FROM THE WEST. MOISTURE/INSTABILITY ARE LIMITED BUT LAPSE RATES ARE STEEP SO SOME SHOWERS AND THUNDERSTORMS WILL BE ABLE TO DEVELOP AHEAD OF THE FRONT. THE BIG FEATURE OF NOTE WILL BE THE SYNOPTIC WINDS. THE LOW LEVEL WIND FIELD WILL BE RAMPING UP TO 40KTS/50KTS AND MODEL SOUNDINGS SHOW A VERY WELL MIXED AND DRY BOUNDARY LAYER THAT WILL BE EFFICIENT FOR DOWNWARD MOMENTUM TRANSFER...ESPECIALLY AS COLDER AIR STARTS TO WORK IN BEHIND THE FRONT. BELIEVE THE SITUATION WILL REMAIN BELOW ADVISORY CRITERIA BUT THE RIDGES MAY SEE GUSTS AROUND 40MPH. ANY SHOWERS/STORMS WILL ALSO HAVE PLENTY OF WIND TO MIX DOWN SO EVEN UNIMPRESSIVE CONVECTIVE CLUSTERS MAY BE QUITE GUSTY. BEHIND THE FRONT WE SHOULD GET ENOUGH HIGH PRESSURE BUILDING IN FROM THE NORTHWEST TO KEEP THINGS QUIET...THOUGH BREEZY...THROUGH THE END OF THE WORKWEEK. TEMPERATURES HAVE BEEN TRENDING COLDER FOR BOTH MAX/MIN TEMPS THURSDAY AND FRIDAY...SO WILL BE SHADING GRIDS IN THAT DIRECTION. SOME OF THE HIGHER TERRAIN WEST OF THE BLUE RIDGE WILL BE FLIRTING WITH TEMPERATURES APPROACHING THE FREEZING MARK BOTH MORNINGS. HOWEVER...THE AG PROGRAM WILL NOT BE IN FULL SWING WEST OF THE RIDGE UNTIL MAY 1 SO THIS IS NOT LIKELY TO CAUSE ANY SIGNIFICANT PROBLEMS. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... AS OF 130 PM EDT MONDAY... NOT MUCH CHANGE TO THIS FORECAST. A SOUTHERN STREAM LOW ARRIVES OVER THE AR/OK BORDER BY SATURDAY MORNING WITH OVERRUNNING CLOUDS WORKING INTO THE AREA FRIDAY AHEAD OF A WARM FRONT. BY SATURDAY ENOUGH MOISTURE TO ALLOW FOR SHOWERS TO FORM BY SATURDAY MORNING WITH BEST FORCING ACROSS THE CAROLINAS. THIS SYSTEM EXITS BY SAT NIGHT WITH SUNDAY BEING A DRY AND COOL/MILD DAY WITH HIGHS IN THE 50S MOUNTAINS TO 60S EAST. HIGH PRESSURE TO ASSUME POSITION OVER THE OHIO VALLEY INTO THE SRN APPALACHIANS MONDAY TO KEEP THINGS DRY. NEXT SOUTHERN STREAM SYSTEM MAY WORK SOME SHOWERS OUR WAY BY TUESDAY. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... AS OF 145 AM EDT TUESDAY... COLD FRONT WAS EAST OF THE BLUE RIDGE EARLY THIS MORNING AND WAS CLOSE TO CROSSING THROUGH KLYH AND KDAN AT 06Z/2AM. HAVE THE FRONT PASSING THROUGH THESE STATIONS AND WINDS BECOMING WEST BY 08Z/4AM. PRESSURE RISES BEHIND THE FRONT WILL BRING WIND GUSTS OF 20 TO 30 KNOTS THROUGH MID TO LATE AFTERNOON. AFTER SUNSET WINDS WILL DIMINISH TO LESS THAN 10 KTS. CURRENTLY SOME MVFR CEILINGS IN THE MOUNTAINS AND RAPIDLY DISSIPATING SHOWERS. LOWER CONFIDENCE ABOUT HOW WIDESPREAD MVFR CEILINGS WILL BE BEFORE 12Z/8AM. VFR CONDITIONS WILL RETURN THIS AFTERNOON WITH HIGH PRESSURE BUILDING IN BEHIND THE FRONT. EXTENDED AVIATION... THEN THE NEXT CHANCE OF MVFR CONDITIONS AND PRECIPITATION WILL BE IN THE MOUNTAINS ON WEDNESDAY AND THURSDAY WITH THE PASSAGE OF A COLD FRONT. HIGH PRESSURE AT THE SURFACE BUILDS SOUTHEAST FROM THE OHIO VALLEY THURSDAY NIGHT INTO FRIDAY. OVERRUNNING CLOUDS WORK INTO THE AREA FRIDAY AHEAD OF A WARM FRONT. BY SATURDAY...ENOUGH MOISTURE TO ALLOW FOR SHOWERS WITH BEST FORCING ACROSS THE CAROLINAS. && .HYDROLOGY... AS OF 405 AM EDT TUESDAY... AFTER THE IMPRESSIVE RAINFALL SINCE SUNDAY MORNING...WHICH SAW OVER 6 INCHES AT A FEW GAGES IN ALLEGHANY COUNTY NC...RIVERS AND LARGE CREEKS IN THE NEW RIVER AND UPPER ROANOKE VALLEYS HAVE MOSTLY CRESTED AND ARE FALLING. STAGES ALONG THE MAINSTEM NEW RIVER WILL CONTINUE TO FALL. ALLISONIA AND RADFORD HAVE RECEDED BACK BELOW FLOOD STAGE. RIVER FLOOD WARNINGS CONTINUE FOR THE LOWER ROANOKE RIVER AT RANDOLPH AND AT DANVILLE AND SOUTH BOSTON ON THE DAN FOR MINOR FLOODING. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...MBS LONG TERM...WP AVIATION...AMS/JH HYDROLOGY...AMS/PC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
341 AM CDT TUE APR 21 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 341 AM CDT TUE APR 21 2015 MAIN FCST CONCERNS THIS PERIOD...STRONG WINDS THIS AFTERNOON... -SHRA/-SHSN CHANCES TODAY INTO THIS EVENING...TEMPERATURES. 06Z DATA ANALYSIS HAD A 984 MB LOW SOUTHWEST OF JAMES BAY CANADA WITH BROAD TROUGHING TO THE SOUTHWEST INTO NORTHERN MN. TIGHT PRESSURE GRADIENT AND STEEPER LOW LEVEL LAPSE RATES REMAINED ACROSS THE REGION...ESPECIALLY MN/WI WHERE WEST TO NORTHWEST WINDS OF 15 TO 20MPH GUSTING 25-35 MPH WERE QUITE COMMON. ONE SHORTWAVE OVER NORTHERN MN INTO NORTHWEST WI WITH THE MID LEVEL LOW COMBINED WITH SOME DEEPER MOISTURE AND TIGHTER 925-700MB CYCLONIC FLOW/ CONVERGENCE WERE PRODUCING SOME -SN/-SHSN OVER NORTHEAST MN INTO THE NORTHWEST 1/4 OF WI. FURTHER SOUTH...WIDELY SCT -SHRA/-SHSN NOTED OVER EAST CENTRAL MN INTO WESTERN WI. 21.00Z MODELS LOOK TO HAVE INITIALIZED WELL. SOLUTIONS QUITE SIMILAR AS THE MID LEVEL LOW OVER NORTHERN MN DROPS ACROSS THE U.P. OF MI TODAY THIS MORNING/EARLY THIS AFTERNOON...THEN LIFTS INTO EAST CENTRAL ONTARIO LATE TODAY/TONIGHT. SOLUTIONS GENERALLY FAVOR COMPROMISE OF THE EARLIER RUNS WITH DEEP...COLD CYCLONIC FLOW OVER THE UPPER MIDWEST THIS PERIOD. SOME DIFFERENCES ON LIGHT QPF PRODUCTION UNDER/SOUTH OF THE MID LEVEL LOW TODAY BUT THIS NOT UNEXPECTED. OVERALL SHORT-TERM FCST CONFIDENCE IS GOOD THIS CYCLE. IN THE SHORT TERM...TIGHT PRESSURE GRADIENT REMAINS OVER THE AREA AGAIN TODAY...WITH STEEP LOW LEVEL LAPSE RATES/MIXING TO 850MB THIS AFTERNOON. BIT MORE WIND IN THE MIXED PORTION OF COLUMN THAN SUNDAY...25-30KTS AT 925MB AND AROUND 35KTS AT 850MB. 700MB TEMPS AROUND -16C AS WELL THIS AFTERNOON WITH POTENTIAL OF MIXING TO 800MB. WILL MATCH UP WITH THE NEIGHBORS AND ISSUE A WIND ADVISORY FOR ROUGHLY THE SOUTHWEST 1/3 OF THE FCST AREA FROM 16Z-23Z TODAY. MODEL SOUNDINGS/X-SECTIONS SHOWING CONSIDERABLE MOISTURE/SATURATION IN THE 900-500MB LAYER TO ROTATE ACROSS ROUGHLY THE NORTHEAST 2/3 OF THE FCST AREA TODAY. THIS WITH THE -16C 700MB COLD POOL...A LOBE OF VORTICITY ROTATING AROUND THE UPPER LOW AND THE TIGHTER 925-700MB CYCLONIC CONVERGENCE...SETS THE STAGE FOR AT LEAST SCT -SHRA/-SHSN ACROSS THE NORTHEAST HALF OF THE FCST AREA TODAY. RAISED PRECIP CHANCES A BIT TODAY ACROSS THE NORTHEAST HALF OF THE FCST AREA... WITH 60+ PERCENT ACROSS THE FAR NORTH END. COLUMN COLD ENOUGH FOR - SHSN AS FAR SOUTH AS I-90 THRU MID MORNING. DIURNAL WARMING/ MIXING OF LOWER PORTION OF THE COLUMN LOOKS TO CHANGE BULK OF PRECIP TO - SHRA BY LATE MORNING...BUT STRONGER SHOWER CORES AND DRIER AIR BELOW 900MB FOR EVAPORATIVE COOLING MAY ALLOW SOME -SN/SLEET/SNOW PELLET SHOWERS TO OCCUR WELL INTO THE AFTERNOON. DAY CREW WILL HAVE TO MONITOR WARMING...AND OBS...AND MAY NEED TO INCLUDE THAT IN GRIDS AS THE DAY WEARS ON. SECONDARY SHORTWAVE ROTATES IN AND ACROSS THE AREA THIS EVENING...WITH A BETTER PV ADVECTION SIGNAL. RAISED -SHRA/ -SHSN CHANCES/LINGERED THEM LONGER OVER THE EAST SIDE OF THE FCST AREA THIS EVENING. 925-500MB SUBSIDENCE AND DRYING OF THE COLUMN SPREADS ACROSS THE FCST AREA LATE THIS EVENING/OVERNIGHT... WITH AND END TO THE -SHRA/-SHSN. SOME CLEARING LATER TONIGHT AS WELL. PRESSURE GRADIENT CONTINUES TO RELAX TONIGHT BUT SFC WINDS LOOKING TO REMAIN IN THE 7-14KT RANGE FOR BOUNDARY LAYER MIXING. EVEN WITH THE WINDS...LOWS LOOKING TO FALL TO NEAR/BELOW FREEZING. A BIT EARLY FOR FROST/FREEZE HEADLINES AT THIS POINT...BUT ANOTHER WEEK OF THE WARMER TEMPS OF LAST WEEK WOULD HAVE LIKELY MADE THEM NEEDED. USED A BLEND OF THE GUIDANCE HIGHS/LOWS FOR TODAY/TONIGHT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 341 AM CDT TUE APR 21 2015 MAIN FCST CONCERNS FOR WED THRU THU NIGHT...COLD TEMPERATURES. 20.12Z MODELS IN GOOD AGREEMENT WED/WED NIGHT FOR THE MID LEVEL LOW/ TROUGH AXIS TO DRIFT SLOWLY EAST...WITH THE UPPER MIDWEST UNDER A COLD NORTHWEST FLOW ALOFT. HGTS SLOWLY RISE THU/THU NIGHT AS THE LOW PULLS INTO MAINE/QUEBEC AND TROUGHING MOVES INTO THE ROCKIES BUT FLOW REMAINS OUT OF THE NORTHWEST. WITH THE TIGHTER/IMPROVING CONSENSUS...FCST CONFIDENCE IN THE WED THRU THU NIGHT PERIOD IS GOOD THIS CYCLE. THE WED THRU THU NIGHT PERIOD IS DOMINATED BY SEASONABLY COLD AND DRY CAN HIGH PRESSURE. SOME MOISTURE FROM LK SUPERIOR...STEEP LOW LEVEL LAPSE RATES AND THE COLD AIR ALOFT LOOK TO SPREAD A SMALL - SHRA/-SHSN CHANCE INTO THE FAR NORTH END OF THE FCST AREA WED... OTHERWISE WED-THU NIGHT TREND DRY AS THE SFC RIDGE AXIS SLOWLY DRIFTS EAST TOWARD/OVER THE AREA. 925MB TEMPS IN THE 0C TO -6C RANGE AT 12Z THU AND IN THE +4C TO -2C RANGE AT 12Z FRI. NAEFS SHOWING 850MB TEMPS 1 TO 2 STANDARD DEVIATIONS BELOW NORMAL ACROSS MUCH OF THE UPPER MIDWEST THRU 12Z FRI. SFC RIDGE AXIS MAY BE CLOSE ENOUGH FOR WINDS TO DECOUPLE WED NIGHT BUT THIS LOOKS MORE CERTAIN THU NIGHT WITH THE RIDGE AXIS SOMEWHERE OVER WI. BOTH NIGHT TRENDING COLD WITH LOWS NEAR OR BELOW 32F. AGAIN...A WEEK OR SO LATER IN THE SEASON/MORE ADVANCED GROWTH/DEVELOPMENT OF VEGETATION AND FROST/ FREEZE HEADLINES WOULD BE NEEDED. APPROACH OF THE HIGH PRESSURE AND SLOWLY RISING HGTS ALOFT TO BRING MORE SUNSHINE TO THE AREA WED/THU. DEEP MIXING TO 750MB INDICATED FOR WED...WITH WINDS IN THE 900-750MB PORTION OF THE COLUMN STILL IN THE 20-30KT RANGE. BREEZY AGAIN WED AFTERNOON...BUT LESS SO THAN SUNDAY AND TODAY. MORE SUNSHINE WED/THU WILL HELP HIGH TEMPS RECOVER INTO THE 50S. USED A BLEND OF THE GUIDANCE HIGHS/LOWS FOR WED THRU THU NIGHT. FOR FRIDAY THRU MONDAY...DAYS 4 TO 7... MAIN FCST CONCERNS THIS PERIOD...MAINLY RAIN CHANCES FRI/FRI NIGHT AND AGAIN LATE SUN INTO MON...TEMPERATURES. 21.00Z MEDIUM RANGE MODELS IN GENERAL AGREEMENT FOR THE PATTERN TO BE PROGRESSIVE FRI/SAT WITH RISING HGTS OVER THE EASTERN CONUS AND TROUGHING MOVING THRU THE ROCKIES INTO THE PLAINS. HOWEVER PLENTY OF SHORTWAVE DETAIL DIFFERENCES ALREADY BY FRI...WHICH WOULD IMPACT THE SENSIBLE WEATHER ACROSS THE UPPER MIDWEST. AGREEMENT FOR WEAK SHORT- WAVE RIDGING OT BUILD INTO THE REGION SAT. NEXT STRONGER TROUGHING IS INTO THE PLAINS SUNDAY...THEN APPROACHING/CROSSING THE REGION SUN NIGHT/MON. RUN-TO-RUN CONSISTENCY LEAVES QUITE A BIT TO BE DESIRED BY SUN/MON WITH TROUGHS OFF BOTH COASTS AND UNCERTAIN FLOW ACROSS THE CONUS BETWEEN THEM. FCST CONFIDENCE FOR FRI THRU MON...AS FAR AS PRECIP CHANCES IS BELOW AVERAGE. AVERAGE CONFIDENCE FOR TEMPERATURES TO RETURN TO NEAR NORMAL BY SUN/MON. TROUGHING MOVING INTO THE PLAINS FRI DEVELOPS LOW PRESSURE OVER THE CENTRAL/SOUTHERN PLAINS...BUT QUESTION IS NOW FAR NORTH INTO THE MID/UPPER MS VALLEY THE INFLUENCE OF THIS LOW GETS. ECMWF/GEM WITH MORE SHORTWAVE RIDGING AHEAD OF THIS FEATURE...AND WOULD SPREAD MOISTURE/PRECIP CHANCES INTO MN/IA/WI FRI/FRI NIGHT. GFS WITH LESS SHORTWAVE RIDGING HOLDS NORTHWEST FLOW ALOFT OVER THE REGION THRU FRI NIGHT...AND KEEPS MN/IA/WI DRY. WITH LESSER CONFIDENCE STAY WITH THE SMALL CONSENSUS MAINLY -SHRA CHANCES FRI/FRI NIGHT. RISING HGTS/ SHORTWAVE RIDGING WOULD BRING DRY HIGH PRESSURE TO THE REGION FOR SAT/SAT NIGHT. NEXT TROUGH THRU THE ROCKIES DEVELOPS LEE TROUGHING FROM MT TO TX ON SUN...WITH SOME FORM OF THIS TROUGH/LOW PUSHING INTO THE MID/UPPER MS VALLEY SUN NIGHT/MON. DEEPER SOUTHERLY FLOW AHEAD OF THIS SYSTEM WOULD BRING WARMER LOW LEVEL AIR/INCREASING MOISTURE NORTHWARD FOR SUN INTO MON. RAIN CHANCES OF 20-30 PERCENT SUN NIGHT/MON PER THE MODEL/ENSEMBLE CONSENSUS APPEAR REASONABLE. MODEL/ENSEMBLE CONSENSUS OF THE HIGHS/LOWS FOR FRI THRU MON ALSO APPEAR WELL TRENDED FOR NOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1140 PM CDT MON APR 20 2015 THE WESTERN EDGE OF THE CLOUD DECK HAS BEEN ERODING SOME THIS EVENING. HOWEVER...LOOKING UPSTREAM INTO MINNESOTA...IT LOOKS LIKE THE WESTERN EDGE HAS BEEN HOLDING FIRM AND AS THIS ROTATES DOWN ACROSS THE AREA...EXPECT THAT SKIES WILL BE REMAIN BROKEN TO OVERCAST THROUGH TUESDAY. FOR THE MOST PART THE CEILINGS HAVE REMAINED VFR...BUT STILL EXPECTING THESE TO COME DOWN TO MVFR. CURRENT MVFR CEILINGS ARE UPSTREAM OVER CENTRAL MINNESOTA AND THESE SHOULD ROTATE ACROSS THE AREA OVERNIGHT. STILL SOME RETURNS ON THE RADAR WITH THE 21.02Z HRRR CONTINUING TO SHOW SOME SCATTERED ACTIVITY THROUGH THE NIGHT...BUT CONFIDENCE THAT ANY OF THESE WILL HIT THE TAF SITES REMAIN LOW. THE 21.00Z NAM BUFKIT SOUNDINGS CONTINUE TO SHOW THE GOOD LOW LEVEL LAPSE RATES REMAINING THROUGH THE ENTIRE PERIOD TO MAINTAIN THE GUSTY WEST TO NORTHWEST WINDS. THE STRONGEST WINDS WILL COME LATE TUESDAY MORNING THROUGH THE AFTERNOON WHEN THE MIXING BECOMES THE DEEPEST ALLOWING THE GUSTS TO BE AROUND 30 KNOTS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...WIND ADVISORY FROM NOON TODAY TO 6 PM CDT THIS EVENING FOR MNZ086-087-094-095. IA...WIND ADVISORY FROM NOON TODAY TO 6 PM CDT THIS EVENING FOR IAZ008>010-018-019-029-030. && $$ SHORT TERM...RRS LONG TERM....RRS AVIATION.....04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1140 PM CDT MON APR 20 2015 .SHORT TERM...(TONIGHT THROUGH TUESDAY) ISSUED AT 235 PM CDT MON APR 20 2015 500 MB LOW/UPPER LEVEL TROUGH MEANDERS SLOWLY EASTWARD ACROSS THE UPPER MISSISSIPPI RIVER TONIGHT-TUE...THEN WOBBLES OVER SOUTHEAST CANADA FOR A FEW DAYS. BITS OF UPPER LEVEL ENERGY WILL ROTATE AROUND THE UPPER LEVEL FEATURE BUT THE DEEPER SATURATION HOLDS ACROSS NORTHERN PARTS OF MN/WI. STRONG SWATH OF 925-700 MB COLD AIR ADVECTION DRIVES SOUTHEAST TONIGHT-TUE...GREATER ACROSS IA. BUFKIT SOUNDINGS STILL SHOWING AS MUCH AS A 100 MB LAYER OF WEAK INSTABILITY TUE AFTERNOON...ASSOCIATED WITH A SATURATED LAYER. ALL IN ALL...THE MIX OF CYCLONIC UPPER LEVEL FLOW...LOW LEVEL COLD AIR ADVECTION...WEAK INSTABILITY...FAVORABLY LOW/MID LEVEL LAPSE RATES...AND SOME SATURATION FAVORS AREAS/SCATTERED SHOWERS. LOCATIONS TO THE NORTH WILL HAVE THE BEST CHANCES...SPREADING SOUTHWARD TUESDAY AFTERNOON. SOME SNOW COULD MIX IN TO THE NORTH EARLY/LATE. BUFKIT SOUNDINGS POINT TO DEEP MIXING ON TUESDAY...ESPECIALLY SOUTH OF I-90 INTO IOWA. MIXING UPWARDS OF 800 MB WITH MOMENTUM TRANSFER OF 30 TO 35 KTS. SFC PRESSURE GRADIENT TUE FAIRLY SIMILAR TO THIS AFTERNOON. EXPECTING CLOUDY/MOSTLY CLOUDY CONDITIONS FOR THE I-90 CORRIDOR NORTHWARD...LIMITING THE MIXING. WITH MORE SUN SOUTH...FULL MIXING COULD BE REALIZED. SEE SOME POTENTIAL FOR WIND ADV TUE AFTERNOON - ESPECIALLY PARTS OF NORTHEAST IA. SOMETHING TO WATCH. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 235 PM CDT MON APR 20 2015 GOOD AGREEMENT IN THE MODELS WITH PERSISTENT COOL NORTHWEST FLOW THROUGH THE REST OF THE WORK WEEK. DIFFERENCES CROP UP FOR THE WEEKEND AS THE ECMWF/GEM POINT TO SOME WEAK UPPER LEVEL RIDGE BUILDING WHILE THE GFS MAINTAINS THE TROUGH - EVEN DEEPENING IT/CARVING IT OUT MORE. WHILE ALL SOLUTIONS FAVOR KEEPING THE LOCAL AREA DRY...THERE WOULD BE IMPACTS ON TEMPS. THE GFS WOULD KEEP HIGHS IN THE LOW/MID 50S WHILE THE EC POINTS TO A RETURN TO NORMAL - AROUND 60. MODELS HAVE BEEN FAIRLY CONSISTENT WITHIN THEMSELVES...BUT STILL NOT SOLD ON THE RIDGING. WILL STICK WITH CONSENSUS SOLUTIONS FOR THE WEEKEND FOR NOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1140 PM CDT MON APR 20 2015 THE WESTERN EDGE OF THE CLOUD DECK HAS BEEN ERODING SOME THIS EVENING. HOWEVER...LOOKING UPSTREAM INTO MINNESOTA...IT LOOKS LIKE THE WESTERN EDGE HAS BEEN HOLDING FIRM AND AS THIS ROTATES DOWN ACROSS THE AREA...EXPECT THAT SKIES WILL BE REMAIN BROKEN TO OVERCAST THROUGH TUESDAY. FOR THE MOST PART THE CEILINGS HAVE REMAINED VFR...BUT STILL EXPECTING THESE TO COME DOWN TO MVFR. CURRENT MVFR CEILINGS ARE UPSTREAM OVER CENTRAL MINNESOTA AND THESE SHOULD ROTATE ACROSS THE AREA OVERNIGHT. STILL SOME RETURNS ON THE RADAR WITH THE 21.02Z HRRR CONTINUING TO SHOW SOME SCATTERED ACTIVITY THROUGH THE NIGHT...BUT CONFIDENCE THAT ANY OF THESE WILL HIT THE TAF SITES REMAIN LOW. THE 21.00Z NAM BUFKIT SOUNDINGS CONTINUE TO SHOW THE GOOD LOW LEVEL LAPSE RATES REMAINING THROUGH THE ENTIRE PERIOD TO MAINTAIN THE GUSTY WEST TO NORTHWEST WINDS. THE STRONGEST WINDS WILL COME LATE TUESDAY MORNING THROUGH THE AFTERNOON WHEN THE MIXING BECOMES THE DEEPEST ALLOWING THE GUSTS TO BE AROUND 30 KNOTS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RIECK LONG TERM....RIECK AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
347 AM MDT TUE APR 21 2015 .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 315 AM MDT TUE APR 21 2015 QUIET WEATHER THIS MORNING WITH SOME MID CLOUDS OVER SE WY KEEPING TEMPS UP A BIT AND HINDERING ANY FOG FORMATION. NWLY FLOW ALOFT WILL REMAIN OVER THE CWA THROUGH WEDS THEN TURN WESTERLY WEDS NIGHT AND THURSDAY. A WEAK FRONT WILL SETTLE DOWN THE PLAINS LATER THIS AFTERNOON INTO THIS EVENING AND LAY UP AGAINST THE MTNS BUT NO SIGNIFICANT EFFECT SEEN FROM THIS THROUGH TONIGHT. SOME WEAK INSTABILITY OVER WESTERN PARTS OF THE CWA SHOULD ALLOW FOR A FEW SHOWERS TO DEVELOP THIS AFTERNOON WITH A TSTORM OR TWO NOT OUT OF THE QUESTION. ACTIVITY WILL DECREASE THIS EVENING. AN APPROACHING SHORTWAVE ON WEDS SHOULD ALLOW FOR SOMEWHAT BETTER COVERAGE OF SHOWERS AND A FEW TSTORMS WEDS...MAINLY OVER SE WY WHERE SOME MINOR UPSLOPE COMPONENT TO THE WIND SHOULD EXIST. SIMILAR PATTERN FOR THURSDAY BUT PCPN SHOULD PROGRESS FARTHER EASTWARD OVER THE PLAINS AND THE PANHANDLE AS THE SFC FRONT SLIPS BACK EAST. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 345 AM MDT TUE APR 21 2015 MINOR DIFFERENCES ARE APPARENT WITH THE 00Z/06Z DETERMINISTIC MODEL GUIDANCE. FAIRLY BROAD UPPER TROUGH OVER THE INTERMOUNTAIN WEST WILL PROGRESS EASTWARD WITH WEAK UPPER LOW MOVING SLOWLY FROM THE FOUR CORNERS TO SOUTHEAST CO THURSDAY NIGHT AND CENTRAL GREAT PLAINS BY FRIDAY EVENING. A SURFACE TROUGH BISECTING A PAIR OF LOWS WILL LIE EAST OF THE LARAMIE RANGE. A RATHER MOIST SOUTHEASTERLY UPSLOPE FLOW WITH DEW POINTS IN THE 40S COMBINED WITH MODEST INSTABILITY /LIS -3 TO -5C/ AND WEAK UPPER LEVEL DISTURBANCE WILL PRODUCE A DECENT COVERAGE OF SHOWERS AND ISOLATED TSTORMS THURSDAY NIGHT AND FRIDAY. SHOWER COVERAGE DECREASES SLIGHTLY FRIDAY NIGHT WITH THE EXIT OF THE DISTURBANCE. SHORTWAVE TRANSITORY RIDGE ALOFT EARLY SATURDAY SLIDES EAST INTO THE PLAINS SATURDAY AFTERNOON WHEN A STRONGER DISTURBANCE MOVES ACROSS WY AND CO PRODUCING SCATTERED SHOWERS AND POSSIBLY A FEW TSTORMS. THE GFS IS MORE PROGRESSIVE WITH THIS TROUGH AND CLEARS OUT THE SHOWERS SATURDAY NIGHT WHILE THE ECMWF IS SLOWER AND KEEPS THE CWA SHOWERY THROUGH SUNDAY. AREAS ALONG AND SOUTH OF I-80 IN SOUTHEAST WY MAY SEE ISOLATED SHOWERS SUNDAY AFTERNOON WITH WEAK OROGRAPHIC FLOW. A DRIER STABLE AIR MASS WILL PREVAIL MONDAY WITH LARGE SCALE RIDGE OVER THE ROCKY MOUNTAINS. TRENDED TOWARD THE COOLER ECMWF BIAS FOR TEMPERATURES WHICH WILL AVERAGE NEAR TO SLIGHTLY ABOVE SEASONAL NORMALS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 239 AM MDT TUE APR 21 2015 DEVELOPMENT OF PATCHY DENSE FOG IN THE LARAMIE VALLEY EARLY THIS MORNING IS NOT FAVORABLE GIVEN THE LARGER TEMP/DEW POINT SPREADS AND BKN-OVC CLOUDS AROUND 8000 FT AGL. THE SREF AND HRRR PREDICT VFR CONDITIONS. THERE COULD BE SOME MIFG AROUND...BUT SHOULD HAVE LIMITED IMPACTS TO AVIATION. OTHERWISE...VFR WILL PREVAIL ACROSS THE FORECAST AREA TODAY AND TONIGHT WITH OCCASIONAL MID AND HIGH CLOUDS PASSING OVERHEAD IN NORTHWEST FLOW. IT WILL BE BREEZY WITH WEST TO NORTHWEST SURFACE WINDS SUSTAINED 12-18 KT...GUSTING UP TO 30 KT. THE WINDS WILL DIMINISH EARLY THIS EVENING WITH THE DECOUPLING OF THE LOW LEVEL BOUNDARY LAYER. && .FIRE WEATHER... ISSUED AT 315 AM MDT TUE APR 21 2015 CONCERNS EXPECTED TO REMAIN LOW FOR THE NEXT SEVERAL DAYS WITH WEATHER CONDITIONS REMAINING NON-CRITICAL OVERALL. A FEW THUNDERSTORMS WILL BE POSSIBLE MAINLY IN THE AFTERNOONS FOR THE NEXT FEW DAYS BUT DRY LIGHTNING IS NOT EXPECTED. TEMPERATURES WILL BE MILD THROUGH THE WEEK. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...RE LONG TERM...MJ AVIATION...MJ FIRE WEATHER...RE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1242 AM MDT TUE APR 21 2015 .UPDATE... ISSUED AT 953 PM MDT MON APR 20 2015 MAIN CONCERN OVERNIGHT IS CERTAINLY THE POTENTIAL FOR FOG DEVELOPMENT FOR AREAS WEST OF THE LARAMIE RANGE...INCLUDING I-80 BETWEEN RAWLINS AND LARAMIE. 00Z NAM IS KEEPING FOG AT BAY WITH LOW BL HUMIDITIES AND A DRIER NEAR SURFACE LAYER BASED OFF THE KLAR FORECAST SOUNDINGS. HRRR IS ALSO CONSISTENTLY SHOWING NO DEVELOPMENT OF FOG OVERNIGHT. BASED ON THIS ENSEMBLE OF GUIDANCE...AND SOME MID CLOUDS DEVELOPING AND MOVING IN FROM THE NORTHWEST WITH A FORECAST WIND DIRECTION FROM THE SOUTHWEST...AM NOT SO CONFIDENT WIDESPREAD DENSE FOG WILL DEVELOP OVERNIGHT. LINGERING SNOWPACK AND LIGHT WINDS WILL CERTAINLY AID IN DEVELOPMENT OF MORE PATCHY AREAS OF FOG ESPECIALLY LATE IN THE NIGHT IN THE LARAMIE VALLEY...WITH VISIBILITIES DROPPING TO PERHAPS ONE HALF MILE OR SO...BUT A WIDESPREAD EVENT SEEMS UNLIKELY AT THIS TIME. THE HIGHEST PROBABILITY OF FOG WILL BE FOR EASTERN AND SOUTHERN PORTIONS OF THE LARAMIE VALLEY...AND PERHAPS NORTHERN CARBON COUNTY AS WELL. WILL HOLD OF ON ISSUING A DENSE FOG ADVISORY FOR NOW DUE TO LOW CONFIDENCE...BUT WILL CLOSELY MONITOR THE SITUATION. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 250 PM MDT MON APR 20 2015 TONIGHT...LOOKS LIKE ENOUGH INSTABILITY IN THE THETA E RIDGE ACROSS OUR FAR SOUTHWEST COUNTIES FOR ISOLATED TO WIDELY SCATTERED EARLY EVENING SHOWERS OVER SOUTHERN CARBON AND ALBANY COUNTIES. DRY ELSEWHERE. BASED ON PERSISTENCE...WILL AGAIN FORECAST AREAS OF FOG OVERNIGHT AND ESPECIALLY AFTER MIDNIGHT FOR MUCH OF CARBON COUNTY AND ESPECIALLY OVER THE LARAMIE VALLEY AND THE SNOWPACK WHERE TEMPERATURE AND DEWPOINT SPREADS ARE STILL ONLY 2 DEGREES AT MID AFTERNOON. TUESDAY...NON DESCRIPT NORTHWEST FLOW ALOFT CONTINUES. LOOKS LIKE ENOUGH LOW AND MID LEVEL MOISTURE ALONG WITH DIFFERENTIAL HEATING AND UPSLOPE TO GENERATE ISOLATED TO WIDELY SCATTERED AFTERNOON SHOWERS...WITH ISOLATED THUNDERSTORMS WEST OF INTERSTATE 25. TUESDAY NIGHT...SHOWERS AND THUNDERSTORMS SHOULD END IN THE EVENING WITH THE LOSS OF DAYTIME HEATING AND LACK OF SIGNIFICANT LIFTING...THOUGH STILL ENOUGH LOW AND MID LEVEL MOISTURE FOR SCATTERED TO BROKEN CLOUD COVER...AND AREAS OF FOG ONCE AGAIN OVER THE LARAMIE VALLEY. WEDNESDAY...TRANSITORY RIDGING ALOFT MOVES OVERHEAD. STILL THOUGH...ENOUGH LOW AND MID LEVEL MOISTURE AND INSTABILITY FOR ISOLATED TO SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS WITH AN INCREASE IN THUNDERSTORM COVERAGE DUE TO INCREASED INSTABILITY. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 250 PM MDT MON APR 20 2015 SHORTWAVE RIDGE MOVES OVER THE AREA WEDNESDAY NIGHT. MOST AREAS EAST OF THE LARAMIE RANGE WILL BE DRY...THOUGH GFS DOES SHOW SOME LIGHT SHOWERS OUT OVER CARBON COUNTY INTO THURSDAY MORNING. RIDGE AXIS MOVES EAST OF THE CWFA THURSDAY WITH AN UPPER SHORTWAVE PUSHING INTO NORTHWESTERN COLORADO AND WESTERN WYOMING. BOTH THE GFS AND ECMWF PAINTING MODERATE QPF OVER THE CWFA THURSDAY AFTERNOON. LIFTED INDICES -2 TO -4C ACROSS THE CWFA WITH -5 TO -6C ACROSS THE PANHANDLE. ADDED THUNDERSTORM MENTION IN THE FORECAST FOR THURSDAY AFTERNOON/EVENING. FRIDAY COULD BE AN INTERESTING DAY THUNDERSTORM WISE AS A SURFACE LOW DEVELOPS OVER NORTHEASTERN COLORADO. UPPER LEVEL LOW ALMOST VERTICALLY STACKED OVER THE SURFACE LOW ON BOTH THE GFS AND ECMWF. GFS MOST BULLISH ON QPF...WITH AN AREA OVER HEAVY RAIN OVER THE SOUTHERN PANHANDLE. LOW SLOW TO MOVE OUT OF THE AREA WITH SHOWER ACTIVITY CONTINUING INTO SATURDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1238 AM MDT TUE APR 21 2015 VFR CONDITIONS WILL PREVAIL OVERNIGHT WITH SCATTERED HIGH CLOUDS OVER SOUTHEAST WY. AREAS OF IFR-LIFR CONDITIONS IN FOG WILL BE POSSIBLE ACROSS THE LARAMIE VALLEY INCLUDING KLAR BETWEEN 10Z AND 14Z TUESDAY. OTHERWISE...SCATTERED TO BROKEN MID AND HIGH CLOUDS ARE EXPECTED DURING THE DAY. IT WILL BE BREEZY TUESDAY AS WEST TO NORTHWEST WINDS GUST BETWEEN 25 AND 30 KT...EXCEPT FOR VALLEY LOCATIONS. && .FIRE WEATHER... ISSUED AT 250 PM MDT MON APR 20 2015 RECENT RAIN AND CONTINUED SNOW PACK FROM LAST WEEKS STORM WILL KEEP FIRE WEATHER CONCERNS MINIMAL THROUGH THE WEEK. GOING TO SEE INCREASED CHANCES FOR WETTING RAINS AND MOUNTAIN SNOWS LATE IN THE WEEK AS ANOTHER PACIFIC LOW PRESSURE SYSTEM TRACKS ACROSS NORTHERN COLORADO. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...RJM SHORT TERM...RUBIN LONG TERM...GCC AVIATION...MJ FIRE WEATHER...GCC
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1013 AM CDT TUE APR 21 2015 .UPDATE... ISSUED AT 1012 AM CDT TUE APR 21 2015 MAIN FORECAST CONCERN WILL BE WITH THE WINDS TODAY. ALREADY STARTING TO SEE WIND GUSTS TO AROUND 30 MPH ACROSS THE NORTHERN CWA. LATEST HRRR AND RAP DATA SUGGESTING A PERIOD OF 40-45 KNOTS FOR A FEW HOURS EARLY THIS AFTERNOON ACROSS MAINLY AREAS ALONG AND NORTH OF I-74...ALTHOUGH THEY ARE ALSO NOW SUGGESTING THIS AS FAR SOUTH AS THE I-70 CORRIDOR. HAVE NOT GONE THAT HIGH SO FAR SOUTH AS CLOUDS THERE WILL BE ON THE INCREASE AND PREVENT FULL MIXING... BUT RAISED THE WIND GUSTS A TAD OVER THE NORTH AS MOSTLY SUNNY CONDITIONS CONTINUE INTO AT LEAST MID AFTERNOON. && .SHORT TERM...(TODAY) ISSUED AT 323 AM CDT TUE APR 21 2015 WINDY CONDITIONS WILL ONCE AGAIN DEVELOP ACROSS CENTRAL ILLINOIS TODAY, THANKS TO A TIGHTENING PRESSURE GRADIENT AND DEEP-LAYER MIXING. THE STRONGEST WINDS WILL BE FOCUSED ALONG/NORTH OF THE I-74 CORRIDOR, WHERE FORECAST SOUNDINGS SUGGEST SUSTAINED WINDS OF AROUND 30MPH WITH GUSTS UP TO 40MPH AT TIMES. WILL THEREFORE ISSUE A WIND ADVISORY FOR THIS AREA FROM 11AM TO 7PM. FURTHER SOUTH ACROSS THE REMAINDER OF THE KILX CWA, WINDS WILL REMAIN BELOW ADVISORY CRITERIA, MAINLY IN THE 25 TO 30MPH RANGE. SKIES WILL BE MOSTLY SUNNY THROUGH MUCH OF THE DAY, WITH AN INCREASE IN CLOUDS NOTED ACROSS THE FAR SOUTH DURING THE AFTERNOON AS A MID-LEVEL SHORT-WAVE APPROACHES FROM THE WEST. ALL MODELS ARE DEVELOPING SCATTERED SHOWERS/THUNDER IN ADVANCE OF THIS WAVE, BUT PRIMARILY KEEP THE ACTIVITY JUST SOUTH OF THE CWA. HIGHER-RES MODELS SUCH AS THE HRRR ARE SLIGHTLY FURTHER NORTH, SO HAVE OPTED TO INCLUDE SLIGHT CHANCE POPS FOR SHOWERS SOUTH OF I-70 THIS AFTERNOON. THANKS TO INCREASED SUNSHINE, HIGH TEMPERATURES WILL BE A FEW DEGREES WARMER THAN YESTERDAY, WITH READINGS CLIMBING INTO THE LOWER TO MIDDLE 60S. .LONG TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 323 AM CDT TUE APR 21 2015 MAIN CHALLENGES IN THE EXTENDED CONTINUE TO BE FROST POTENTIAL WEDNESDAY/THURSDAY NIGHTS, AS WELL AS, TIMING OF NEXT PRECIP EVENT BY THE END OF THE WEEK. DEEP UPPER LOW CURRENTLY CENTERED OVER THE WESTERN GREAT LAKES WILL BE THE DOMINANT WEATHER FEATURE ACROSS THE MIDWEST FOR THE NEXT FEW DAYS, RESULTING IN COOL CONDITIONS THROUGH FRIDAY. AS A PIECE OF ENERGY ROTATES AROUND THE LOW, A WEAK COLD FRONT WILL DROP THROUGH ILLINOIS TONIGHT. FORECAST SOUNDINGS ARE INITIALLY QUITE DRY: HOWEVER, THE LATEST MODELS SHOW QUITE A BIT MORE TOP-DOWN MOISTENING THAN IN PREVIOUS RUNS. AS A RESULT, THINK SCATTERED LIGHT SHOWERS WILL ACCOMPANY THE FRONT TONIGHT, WITH PERHAPS A FEW SHOWERS LINGERING INTO WEDNESDAY MORNING ACROSS THE FAR SE. ONCE THE FRONT EXITS, CANADIAN HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE MIDDLE AND END OF THE WEEK. THE RIDGE AXIS IS PROGGED TO BE JUST WEST OF THE MISSISSIPPI RIVER BY 12Z THURSDAY, SO AM EXPECTING WINDS TO DIMINISH CONSIDERABLY AS THE PRESSURE GRADIENT WEAKENS. WITH CLEAR SKIES AND LIGHT WINDS, OVERNIGHT LOWS WILL DIP INTO THE LOWER TO MIDDLE 30S, LEADING TO FROST DEVELOPMENT ACROSS MUCH OF THE AREA. IF SKIES REMAIN CLEAR, ANOTHER POTENTIALLY FROSTY NIGHT WILL OCCUR THURSDAY NIGHT AS WELL. FURTHER OUT, MODELS ARE HAVING CONSIDERABLE DIFFICULTY PINNING DOWN THE END OF THE WEEK SYSTEM. SOLUTIONS HAVE BEEN FLIP-FLOPPING FROM RUN TO RUN, SO OVERALL FORECAST CONFIDENCE BEYOND THURSDAY REMAINS LOWS. THE 00Z APR 21 GFS HAS MADE A MAJOR SHIFT BACK TO A SOLUTION IT FEATURED A COUPLE OF DAYS AGO. MEANWHILE, BOTH THE ECMWF AND GEM SEEM TO BE HEADING IN THE OPPOSITE DIRECTION. GIVEN SO MUCH MODEL INCONSISTENCY, PREFER TO MAKE VERY FEW CHANGES TO THE EXTENDED. WITH CANADIAN HIGH PRESSURE INITIALLY IN PLACE ACROSS THE MIDWEST ON WEDNESDAY/THURSDAY, STILL THINK A SLOWER ARRIVAL OF THE NEXT STORM SYSTEM MAKES SENSE. AS A RESULT, HAVE KEPT FRIDAY DRY DESPITE WHAT THE ECMWF AND GEM ARE ADVERTISING. HAVE INTRODUCED POPS FRIDAY NIGHT INTO SATURDAY AS A SYSTEM OVER THE DESERT SOUTHWEST GETS KICKED EASTWARD. STILL QUITE A BIT OF UNCERTAINTY CONCERNING HOW FAR NORTH PRECIP WILL SPREAD, BUT HAVE STUCK WITH PREVIOUS THINKING OF KEEPING HIGHEST POPS FOCUSED ACROSS THE SOUTHERN HALF OF THE CWA. THIS IS IN GOOD AGREEMENT WITH THE LATEST GFS, BUT NOT THE ECMWF/GEM WHICH BOTH FOCUS PRECIP MUCH FURTHER NORTH. ONCE THE SYSTEM EXITS, A RETURN TO DRY WEATHER IS ANTICIPATED FOR SUNDAY BEFORE ANOTHER FAST-MOVING NORTHERN-STREAM WAVE POTENTIALLY BRINGS A FEW SHOWERS BACK INTO THE PICTURE BY MONDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 634 AM CDT TUE APR 21 2015 VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. CLEAR SKIES WILL GIVE WAY TO SCATTERED MID CLOUDS ADVECTING THROUGH THE AREA THIS MORNING AND INTO THIS AFTERNOON. HEIGHT OF CLOUDS WILL LOWER TO AROUND 8KFT LATER THIS EVENING JUST AHEAD OF A WEAK COLD FRONT EXPECTED TO MOVE THROUGH THE AREA TONIGHT. BELIEVE LOWER LAYERS WILL BE TOO DRY FOR PCPN AT FIRST, BUT THINKING SHOWERS WILL BE POSSIBLE IN CONJUNCTION WITH THE FRONT BEGINNING LATE IN THE EVENING AND CONTINUING INTO THE OVERNIGHT HOURS. CIGS MAY LOWER INTO MVFR RANGES WITH PCPN, BUT NOT CONFIDENT WITH THIS, SO WILL KEEP CIGS IN VFR RANGES. PCPN WILL LIKELY END BEFORE SUNRISE. WEST WINDS WILL BECOME QUITE GUSTY AGAIN TODAY AND SHOULD GET UP TO 30-35KTS DURING THE AFTERNOON. AFTER SUNSET WINDS WILL TAPER OFF BUT STILL LOOKING AT 11-13KTS DURING THE EVENING. AS THE FRONT MOVES THROUGH AROUND MIDNIGHT, WINDS WILL BECOME NORTHWESTERLY AND STILL OVER 10KTS. && .ILX WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ027>031-037-038- 043>046. && $$ UPDATE...GEELHART SHORT TERM...BARNES LONG TERM...BARNES AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS LINCOLN IL
634 AM CDT TUE APR 21 2015 .SHORT TERM...(TODAY) ISSUED AT 323 AM CDT TUE APR 21 2015 WINDY CONDITIONS WILL ONCE AGAIN DEVELOP ACROSS CENTRAL ILLINOIS TODAY, THANKS TO A TIGHTENING PRESSURE GRADIENT AND DEEP-LAYER MIXING. THE STRONGEST WINDS WILL BE FOCUSED ALONG/NORTH OF THE I-74 CORRIDOR, WHERE FORECAST SOUNDINGS SUGGEST SUSTAINED WINDS OF AROUND 30MPH WITH GUSTS UP TO 40MPH AT TIMES. WILL THEREFORE ISSUE A WIND ADVISORY FOR THIS AREA FROM 11AM TO 7PM. FURTHER SOUTH ACROSS THE REMAINDER OF THE KILX CWA, WINDS WILL REMAIN BELOW ADVISORY CRITERIA, MAINLY IN THE 25 TO 30MPH RANGE. SKIES WILL BE MOSTLY SUNNY THROUGH MUCH OF THE DAY, WITH AN INCREASE IN CLOUDS NOTED ACROSS THE FAR SOUTH DURING THE AFTERNOON AS A MID-LEVEL SHORT-WAVE APPROACHES FROM THE WEST. ALL MODELS ARE DEVELOPING SCATTERED SHOWERS/THUNDER IN ADVANCE OF THIS WAVE, BUT PRIMARILY KEEP THE ACTIVITY JUST SOUTH OF THE CWA. HIGHER-RES MODELS SUCH AS THE HRRR ARE SLIGHTLY FURTHER NORTH, SO HAVE OPTED TO INCLUDE SLIGHT CHANCE POPS FOR SHOWERS SOUTH OF I-70 THIS AFTERNOON. THANKS TO INCREASED SUNSHINE, HIGH TEMPERATURES WILL BE A FEW DEGREES WARMER THAN YESTERDAY, WITH READINGS CLIMBING INTO THE LOWER TO MIDDLE 60S. .LONG TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 323 AM CDT TUE APR 21 2015 MAIN CHALLENGES IN THE EXTENDED CONTINUE TO BE FROST POTENTIAL WEDNESDAY/THURSDAY NIGHTS, AS WELL AS, TIMING OF NEXT PRECIP EVENT BY THE END OF THE WEEK. DEEP UPPER LOW CURRENTLY CENTERED OVER THE WESTERN GREAT LAKES WILL BE THE DOMINANT WEATHER FEATURE ACROSS THE MIDWEST FOR THE NEXT FEW DAYS, RESULTING IN COOL CONDITIONS THROUGH FRIDAY. AS A PIECE OF ENERGY ROTATES AROUND THE LOW, A WEAK COLD FRONT WILL DROP THROUGH ILLINOIS TONIGHT. FORECAST SOUNDINGS ARE INITIALLY QUITE DRY: HOWEVER, THE LATEST MODELS SHOW QUITE A BIT MORE TOP-DOWN MOISTENING THAN IN PREVIOUS RUNS. AS A RESULT, THINK SCATTERED LIGHT SHOWERS WILL ACCOMPANY THE FRONT TONIGHT, WITH PERHAPS A FEW SHOWERS LINGERING INTO WEDNESDAY MORNING ACROSS THE FAR SE. ONCE THE FRONT EXITS, CANADIAN HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE MIDDLE AND END OF THE WEEK. THE RIDGE AXIS IS PROGGED TO BE JUST WEST OF THE MISSISSIPPI RIVER BY 12Z THURSDAY, SO AM EXPECTING WINDS TO DIMINISH CONSIDERABLY AS THE PRESSURE GRADIENT WEAKENS. WITH CLEAR SKIES AND LIGHT WINDS, OVERNIGHT LOWS WILL DIP INTO THE LOWER TO MIDDLE 30S, LEADING TO FROST DEVELOPMENT ACROSS MUCH OF THE AREA. IF SKIES REMAIN CLEAR, ANOTHER POTENTIALLY FROSTY NIGHT WILL OCCUR THURSDAY NIGHT AS WELL. FURTHER OUT, MODELS ARE HAVING CONSIDERABLE DIFFICULTY PINNING DOWN THE END OF THE WEEK SYSTEM. SOLUTIONS HAVE BEEN FLIP-FLOPPING FROM RUN TO RUN, SO OVERALL FORECAST CONFIDENCE BEYOND THURSDAY REMAINS LOWS. THE 00Z APR 21 GFS HAS MADE A MAJOR SHIFT BACK TO A SOLUTION IT FEATURED A COUPLE OF DAYS AGO. MEANWHILE, BOTH THE ECMWF AND GEM SEEM TO BE HEADING IN THE OPPOSITE DIRECTION. GIVEN SO MUCH MODEL INCONSISTENCY, PREFER TO MAKE VERY FEW CHANGES TO THE EXTENDED. WITH CANADIAN HIGH PRESSURE INITIALLY IN PLACE ACROSS THE MIDWEST ON WEDNESDAY/THURSDAY, STILL THINK A SLOWER ARRIVAL OF THE NEXT STORM SYSTEM MAKES SENSE. AS A RESULT, HAVE KEPT FRIDAY DRY DESPITE WHAT THE ECMWF AND GEM ARE ADVERTISING. HAVE INTRODUCED POPS FRIDAY NIGHT INTO SATURDAY AS A SYSTEM OVER THE DESERT SOUTHWEST GETS KICKED EASTWARD. STILL QUITE A BIT OF UNCERTAINTY CONCERNING HOW FAR NORTH PRECIP WILL SPREAD, BUT HAVE STUCK WITH PREVIOUS THINKING OF KEEPING HIGHEST POPS FOCUSED ACROSS THE SOUTHERN HALF OF THE CWA. THIS IS IN GOOD AGREEMENT WITH THE LATEST GFS, BUT NOT THE ECMWF/GEM WHICH BOTH FOCUS PRECIP MUCH FURTHER NORTH. ONCE THE SYSTEM EXITS, A RETURN TO DRY WEATHER IS ANTICIPATED FOR SUNDAY BEFORE ANOTHER FAST-MOVING NORTHERN-STREAM WAVE POTENTIALLY BRINGS A FEW SHOWERS BACK INTO THE PICTURE BY MONDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 634 AM CDT TUE APR 21 2015 VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. CLEAR SKIES WILL GIVE WAY TO SCATTERED MID CLOUDS ADVECTING THROUGH THE AREA THIS MORNING AND INTO THIS AFTERNOON. HEIGHT OF CLOUDS WILL LOWER TO AROUND 8KFT LATER THIS EVENING JUST AHEAD OF A WEAK COLD FRONT EXPECTED TO MOVE THROUGH THE AREA TONIGHT. BELIEVE LOWER LAYERS WILL BE TOO DRY FOR PCPN AT FIRST, BUT THINKING SHOWERS WILL BE POSSIBLE IN CONJUNCTION WITH THE FRONT BEGINNING LATE IN THE EVENING AND CONTINUING INTO THE OVERNIGHT HOURS. CIGS MAY LOWER INTO MVFR RANGES WITH PCPN, BUT NOT CONFIDENT WITH THIS, SO WILL KEEP CIGS IN VFR RANGES. PCPN WILL LIKELY END BEFORE SUNRISE. WEST WINDS WILL BECOME QUITE GUSTY AGAIN TODAY AND SHOULD GET UP TO 30-35KTS DURING THE AFTERNOON. AFTER SUNSET WINDS WILL TAPER OFF BUT STILL LOOKING AT 11-13KTS DURING THE EVENING. AS THE FRONT MOVES THROUGH AROUND MIDNIGHT, WINDS WILL BECOME NORTHWESTERLY AND STILL OVER 10KTS. && .ILX WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 11 AM THIS MORNING TO 7 PM CDT THIS EVENING FOR ILZ027>031-037-038-043>046. && $$ SHORT TERM...BARNES LONG TERM...BARNES AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
649 AM CDT Tue Apr 21 2015 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 300 AM CDT TUE APR 21 2015 Deep upper low over the Great Lakes was making slow eastward progress early this morning with likely a few small scale waves rotating around it through the Northern and Central Plains. Periodic mid cloud was present over the local area via isentropic upglide from rather brisk and backed mid level winds. At least minor amounts of EPV along the moist layer allowing some showers to form aloft, with weak returns on radar showing some very light precip reaching to the lower troposphere. HRRR and RAP runs quite similar to some 4km WRF runs with light precip forming over central Kansas in the next few hours, with latest IR imagery indicating recent cloud development there. All nearby 0Z soundings measured 850mb dewpoint depressions around 12C, making measurable amounts hard to imagine in this activity. A somewhat more unstable airmass develops over the southeast quarter of Kansas this afternoon with weak surface convergence. Will maintain small storm chances with still minor isentropic lift and weak wave potential in place. The stronger wind fields aloft could lead to some storm organization along with CAPE around 500 J/kg and dry adiabatic low level lapse rates to produce a very small threat for severe wind and hail in the mid afternoon to early evening. Areas outside of storms could also see a few rather strong wind gusts with mixing depths reaching 7000-10000ft AGL though some veering remains through the column. The still dry airmass and gusty winds lead to elevated fire danger in western locations this afternoon. Cold front via a stronger wave rotating around the low arrives this evening and makes quick south progress through the state tonight. Moisture, though modest, will continue to pool ahead of this front for some storm chances through much of the night in the southern zones, with typical diurnal trends allowing severe concerns to diminish. Models are allowing the boundary layer to decouple fairly quickly behind the front, but am somewhat skeptical of this given the baroclinic zone they advertise. If winds can fall quicker than expected, fairly clear skies could present a frost concern, but even if they do the window of cold and calm conditions for formation should be rather limited. Will mention patchy frost in far north where concern is highest. .LONG TERM...(Wednesday through Monday) Issued at 300 AM CDT TUE APR 21 2015 Eastern Kansas remains on the southwest side of an upper surface high for Wednesday, keeping high temperatures around 60 for most of the area. Have kept rain chances out of the southern areas with better chances south. Dry conditions continue Wednesday night into Thursday, with lows in the upper 30s to near 40 and highs climbing toward the middle 60s Thursday. Upper pattern starts to shift Thursday night as shortwave ridge noses out of the southern plains into our area, ahead of an upper trof lifting northeast out of the four corners region. Initial sensible weather impacts should be warmer lows in the 40s near 50 Thursday night with some showers possible after midnight as low level jet makes a return over the area. Latest EC appears to be trending toward the GFS solution for this shortwave as it moves into the plains, taking a faster track and developing the warm front from the surface low out into eastern or southeast Kansas. GFS keeps the boundary south of the area and would make for cloudy cool and rainy conditions area wide for Friday and Saturday night, and with EC solutions also trending this way, have gone with forecast as such. Southern branch of the upper jet takes the shortwave trof east of the area rather quickly on Saturday, with rain ending sometime during the morning hours. Cooler high pressure once again noses into the area behind the departing low and holds temperatures in the low 60s, followed by overnight lows in the 40s. Highs on Sunday rise a bit more into the middle 60s, and have kept rain chances relegated to north and west while surface high continues over the east. Another front progged to move across the area Sunday night with northwest flow aloft returning on Monday. Current forecast is for highs near 70, but this will depend on how strong the front and wave are as to how much cooler air it does, or does not, bring southward. && .AVIATION...(For the 12Z TAFs through 12Z Wednesday Morning) Issued at 649 AM CDT TUE APR 21 2015 VFR conditions anticipated. Periods of mid cloud should dominate with a small chance for -SHRA through much of the forecast, though still of high-based variety. Wind gusts could push beyond forecast parameters a few times in very deep mixing from 20Z-00Z but should be exception. Cold front passage brings wind shift around 04Z. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...65 LONG TERM...67 AVIATION...65
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
632 AM CDT TUE APR 21 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 355 AM CDT TUE APR 21 2015 AN ARCTIC COLD FRONT ACROSS NORTH DAKOTA WILL BACK INTO THE FCST AREA THIS AFTN PRODUCING SOME CLOUDINESS. THE FRONT WILL CONTINUE TO MOVE SOUTH AND WEST TONIGHT. BY 12Z WEDNESDAY A SMALL AREA OF HIGH PRESSURE HAS SETTLED OVER NCNTL NEB WHICH SHOULD PRODUCE LOWS IN THE 20S. BY THIS TIME...THE MODELS SUGGEST ANY CLOUD COVER WOULD LIE ACROSS THE PANHANDLE AND SOUTHWEST NEB WHICH WOULD HOLD UP LOWS IN THE LOWER 30S. HIGHS TODAY RISE INTO THE 60S AHEAD OF THE FRONT WITH 50S NORTH OF THE FRONT ALONG HIGHWAY 20. THE MIDLEVEL CLOUD COVER ACROSS CNTL/SERN NEB EARLY THIS MORNING IS ASSOCIATED WITH 700MB FRONTOGENESIS. THE RAP MOVES THESE CLOUDS SOUTHEAST AND THEN DROPS A SECOND BATCH OF CLOUDS INTO NRN NEB AS EARLY AS 15Z WHICH HANG AROUND MOST OF THE DAY AND THEN MOVE SOUTH AND WEST TONIGHT. THE RADAR RETURNS ACROSS NORTH DAKOTA MOVE EAST OF THE FCST AREA IN THE NAM MODEL WHILE THE HRRR SHOWS TOO MUCH DRY AIR IN THE LOWER LEVELS FOR ANYTHING MORE THAN SPRINKLES THIS AFTN AND TONIGHT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 355 AM CDT TUE APR 21 2015 SURFACE HIGH PRESSURE QUICKLY FOLLOWS THE COLD FRONT AND WILL SLIDE SOUTHEAST OF THE AREA EARLY IN THE DAY ON WEDNESDAY WITH SOUTHERLY WINDS DEVELOPING. DESPITE SOUTHERLY WINDS...COOL AIR ALOFT...850 TEMP FROM 3C EAST TO 8C WEST...AND EVEN WITH SUN AND GOOD MIXING...HIGHS IN THE UPPER 50S AND LOWER 60S. MEANWHILE AN UPPER LEVEL LOW LIFTS TOWARDS THE DESERT SW. MODELS ALSO SHOW A WEAK SYSTEM AHEAD OF THE MAIN LOW...PUSHING ACROSS THE SOUTHERN PLAINS. A SECOND WAVE EJECTS FROM THE MAIN LOW AND ARRIVES TO THE SOUTHERN/CENTRAL PLAINS WED NIGHT INTO THURSDAY. MARGINAL LIFT INTO SW NEB MAY RESULT IN A FEW LIGHT SHOWERS INITIALLY. A BETTER CHANCE ARRIVES LATER IN THE DAY ON THURSDAY AFTER WE GET SOME HEATING. MODELS INCREASE CAPES TO A FEW 100 J/KG AND LIFTED INDEX VALUES AROUND ZERO OR SLIGHTLY NEG. GENERALLY THING ACTIVITY WILL BE SOME SHOWERS AND A FEW RUMBLES OF THUNDER HERE OR THERE. BY FRIDAY THE MAIN LOW WILL BE CROSSING THE ROCKIES. MOISTURE CONTINUES TO INCREASE AHEAD OF THE LOW AND FRIDAY LOOKS TO SEE A WAVE OR TWO OF SHOWERS TO ROTATE THROUGH THE AREA. BETTER MOISTURE LIFT ASSOCIATED CLOSER TO THE LOW...WHICH FAVORS HIGHER POPS ACROSS SW NEB. A SECOND WAVE...CLIPPER...QUICKLY FOLLOWS FOR THE WEEKEND. SHOULD SEE A BRIEF BREAK IN THE ACTIVITY BEFORE THE SECOND WAVE ARRIVES...ALTHOUGH TIMING THE BREAK IS DIFFICULT DUE TO MODEL DIFFERENCES. FORECAST DOES RETAIN LOW POPS AND EXPECT THIS TO CHANGE IN THE COMING DAYS AS THE LULL IN ACTIVITY BECOMES MORE CLEAR. AT THIS TIME MODELS ARE IN FAVOR OF THE DRY PERIOD TO OCCUR SOMETIME SATURDAY...EARLIEST IS THE GEM/GFS...WHILE LATER IS FAVORED BY THE ECMWF. THE NEXT WAVE SHOULD BE EAST OF THE AREA TO START THE WORK WEEK DRY AND MILD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 630 AM CDT TUE APR 21 2015 THE MID LEVEL CLOUDS ACROSS SD WILL SPREAD SOUTH THROUGH THE FORECAST AREA TODAY AND EXIT SOUTH AND WEST TONIGHT. VFR IS EXPECTED ALL AREAS DURING THIS TIME. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...CDC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
955 AM EDT TUE APR 21 2015 .SYNOPSIS...HIGH PRESSURE WILL BUILD OVER NC FROM THE SOUTHWEST TODAY AND TONIGHT... THEN SHIFT EAST OFF THE COAST TUESDAY NIGHT INTO WEDNESDAY. A DRY COLD FRONT WILL APPROACH FROM THE NORTH WEDNESDAY NIGHT AND PUSH SOUTH OF THE REGION THURSDAY. && .NEAR TERM /THROUGH TODAY/... AS OF 955 AM TUESDAY... THE LATEST SURFACE ANALYSIS SHOWED THE COLD FRONT OFFSHORE WITH A WEAK SURFACE TROUGH TOWARD THE MOUNTAINS. DRY AIR WAS NOTED ON THE LATEST WATER VAPOR IMAGES...AND ALSO SHOWN ON UPPER-AIR ANALYSES AND THE KGSO 12Z SOUNDING. WINDS ALOFT WERE STRONGER THAN FORECAST BY GUIDANCE...AND THIS SHOULD TRANSLATE INTO SOME SURFACE WIND GUSTS AT LEAST AROUND 20KT BASED ON THE LATEST RAP SOUNDINGS...POSSIBLY BRIEFLY TO 25KT IN A FEW SPOTS. OUTSIDE OF FEW-TO-SCATTERED CU TOWARD THE TRIAD ON THE LATEST VISIBLE SATELLITE IMAGES...RAP SOUNDINGS SUGGEST CONSIDERABLE SUNSHINE THROUGHOUT CENTRAL NORTH CAROLINA. SURFACE DEW POINTS HAD FALLEN QUICKLY AND LEANED TOWARD THE LOWER DEW POINT OF THE RAP MODEL THIS AFTERNOON AS A RESULT... MAKING FOR SOME MINIMUM RELATIVE HUMIDITIES IN THE 20S PERCENT PARTICULARLY OVER THE NORTHWEST PIEDMONT. RECENT RAIN AND WET GROUND SHOULD KEEP FIRE WEATHER CONCERNS LOW. 1000-850MB THICKNESSES AND GOOD MIXING PROVIDE FOR EXPECTED HIGHS AS CURRENTLY FORECAST... LEANING TOWARD THE WARMER MET MOS GUIDANCE FOR HIGHS PRIMARILY 69 TO 74. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... AS OF 1240 AM TUESDAY... CLEAR AND COOL CONDITIONS EXPECTED TONIGHT. LOWS IN THE MID 40S WITH LIGHT WINDS. WEDNESDAY... THE MAIN ISSUE WILL BE THE EXPECTED GUSTY RETURN FLOW DEVELOPING LATE MORNING THROUGH THE AFTERNOON FROM THE SW. WINDS SHOULD INCREASE TO 15-20 MPH WITH GUSTS TO 30 MPH OUT AHEAD OF THE APPROACHING DRY COLD FRONT. HIGHS WILL WARM INTO THE MID TO UPPER 70S WITH PARTLY SUNNY SKIES. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... AS OF 1212 AM TUESDAY... A MOISTURE STARVED COLD FRONT IS EXPECTED TO PUSH SOUTH THROUGH CENTRAL NORTH CAROLINA WEDNESDAY NIGHT... THEN STALL WELL SOUTH OVER SOUTH CAROLINA THURSDAY INTO FRIDAY. THE MAIN MOISTURE SOURCES ARE FORECAST TO BE CUT OFF AS THIS FRONT MOVES THROUGH WEDNESDAY NIGHT. WEAK HIGH PRESSURE WILL BUILD SOUTHEAST FROM THE OHIO VALLEY INTO NORTH CAROLINA LATER THURSDAY INTO FRIDAY. SENSIBLE WEATHER WEDNESDAY NIGHT WILL FEATURE ONLY A CHANCE OF A SPRINKLE OR TWO OR A VERY LIGHT SHOWER WITH THE FRONT. LOWS GENERALLY FROM 50 NORTH INTO THE UPPER 50S SOUTH. MOSTLY SUNNY SKIES THURSDAY WILL GIVE WAY TO SOME INCREASE IN MID AND HIGH CLOUDS IN THE WEST AND SOUTH FRIDAY. HIGHS BOTH DAYS SHOULD BE AROUND 70 INTO THE LOWER 70S SOUTH. LOWS THURSDAY NIGHT GENERALLY IN THE 40S. SATURDAY THROUGH MONDAY... THE BEST CHANCE OF RAIN IS EXPECTED TO BE SATURDAY INTO SUNDAY AS THE ACTIVE SOUTHERN BRANCH JET SYSTEM TRACKS ACROSS THE LOWER MISSISSIPPI VALLEY TOWARD THE SOUTHEASTERN STATES. UNCERTAINTY WITHIN THE MODELS CONTINUE WITH THE TIMING/STRENGTH/ AND TRACK WITH THE SYSTEM. MODELS CONTINUE TO SHOW A DEEP TROUGH OVER SE CANADA AND THE EASTERN STATES AS WELL WHICH WILL ESSENTIALLY GUARANTEE BELOW NORMAL LATE APRIL TEMPERATURES THIS WEEKEND INTO NEXT WEEK. THE BIG QUESTION WILL BE HOW MUCH RAIN WILL FALL OVER THE WEEKEND WITH THE SOUTHERN BRANCH SYSTEM. WE WILL MAINTAIN CHANCE POP WITH INCREASING CONFIDENCE FOR THE WEEKEND. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... AS OF 650 AM TUESDAY... VFR CONDITIONS ARE NOW EXPECTED THROUGH THURSDAY OR FRIDAY. SUB-VFR CONDITIONS ARE EXPECTED TO DEVELOP WITH RAIN BY SATURDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BADGETT NEAR TERM...DJF SHORT TERM...BADGETT LONG TERM...BADGETT AVIATION...BADGETT
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
644 AM EDT TUE APR 21 2015 .SYNOPSIS... A STRONG LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL BRING VERY WINDY CONDITIONS TODAY...ALONG WITH A CHANCE OF SHOWERS AT TIMES THROUGH WEDNESDAY MORNING. DRIER CONDITIONS ARE EXPECTED FROM WEDNESDAY AFTERNOON THROUGH THE REST OF THE WEEK...WITH BREEZY AFTERNOONS AND COOL TEMPERATURES. ANOTHER CHANCE OF RAIN WILL ARRIVE ON SATURDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SCATTERED TO BROKEN CLOUDS IN THE 6KFT-10KFT LAYER ARE CROSSING THE ILN CWA FROM WEST TO EAST...DELINEATED VERY NICELY ON IR SATELLITE. WITHIN THESE PATCHES OF CLOUDS ARE SOME CONVECTIVE-LOOKING SHOWERS...AND ALTHOUGH NO LIGHTNING HAS BEEN OBSERVED...PEA SIZE HAIL WAS OBSERVED WITH ONE OF THE SHOWERS (THANKS TO THE FREEZING LEVELS OF AROUND 4KFT). THE PRIMARY CONCERN TODAY REMAINS THE THREAT FOR STRONG WINDS...AND AN ANALYSIS OF 00Z MODEL DATA SUPPORTED MAINTAINING THE CURRENT ORIENTATION FOR THE WIND ADVISORY (WITH A SPECIAL WEATHER STATEMENT FOR THE REST OF THE FORECAST AREA). STRONG UNIDIRECTIONAL FLOW (AT ABOUT 250 DEGREES) EXTENDS THROUGH THE ENTIRE DEPTH OF THE TROPOSPHERE...WITH VALUES STEADILY INCREASING OFF THE SURFACE. USING A RECENT RAP RUN AT KDAY ON BUFKIT AS AN EXAMPLE (AT 18Z)...WINDS INCREASE TO 40 KNOTS AT 825MB...THEN 50 KNOTS AT 700MB...AND 60 KNOTS AT 600MB. TODAY WILL BE AN EXERCISE IN MIXING...AS THE EVENTUAL DEPTH OF THE MIXED LAYER WILL LIKELY DETERMINE JUST HOW STRONG THE WINDS GET. GUSTS IN THIS FORECAST WERE GENERALLY GLEANED FROM BUFKIT MOMENTUM TRANSFER VIA RAP/GFS FORECASTS...WITH VALUES IN THE LOWER 40 KNOT RANGE IN THE NORTHERN CWA...AND LOWER 30 KNOT RANGE IN THE SOUTHERN CWA. ALTHOUGH CLEAR SKIES WILL BE IN PLACE AT THE BEGINNING OF THE DAY...WEAK ELEVATED FORCING AND A SLIGHT INCREASE IN MOISTURE AT THE TOP OF THE (RATHER HIGH) MIXED LAYER WILL RESULT IN SOME CLOUD DEVELOPMENT...AND EVENTUALLY SHOWERS IN THE SOUTHEASTERN HALF OF THE FORECAST AREA. THESE SHOWERS MAY BE VERY HIGH-BASED (PERHAPS 8000 FEET)...WITH SCATTERED COVERAGE AT MOST. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... PRECIPITATION IS EXPECTED TO MOVE INTO THE REGION (OR PERHAPS DEVELOP OVER THE FORECAST AREA) ON TUESDAY NIGHT INTO WEDNESDAY MORNING. ALTHOUGH THERE ARE SOME MODEL DIFFERENCES WITH REGARDS TO THE INTENSITY AND LAYOUT OF THE PRECIPITATION...THE OVERALL TIMING APPEARS TO FAVOR THE 06Z-15Z TIME FRAME FOR THE ILN FORECAST AREA...AHEAD OF A SHORTWAVE AND A SURFACE COLD FRONT. ALTHOUGH THIS FRONT SHOWS UP NICELY ON MSLP PLOTS...THE WIND SHIFT AND CHANGE IN AIR MASS ARE NOT ESPECIALLY NOTABLE. INSTABILITY (EVEN ELEVATED) WILL BE HARD TO COME BY...SO THOUGH THUNDER IS NOT AN IMPOSSIBILITY WITH THIS SETUP...THE CHANCE SEEMS VERY LOW. ONCE THIS FRONT PASSES...VERY SIMILAR CONDITIONS ARE EXPECTED FOR THE REST OF THE WEEK...WITH NORTHWEST FLOW AND COOL WEATHER. OHIO IS LIKELY TO REMAIN IN BETWEEN AREAS OF ENHANCED MOISTURE FROM THE NORTHERN AND SOUTHERN STREAMS...LEADING TO GENERALLY SUNNY CONDITIONS UNTIL FRIDAY NIGHT. TEMPERATURES ON THURSDAY AND FRIDAY MORNING MAY BE COOL ENOUGH FOR FROST...BUT MOISTURE AND WIND FORECASTS ARE NOT AS FAVORABLE. THUS...FROST WILL NOT BE INCLUDED IN THE GRIDS OR HWO. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... SOME DEEPER MOISTURE WILL BE PULLED UP TOWARD OUR AREA ON SATURDAY AHEAD OF SHORT WAVE ENERGY MOVING OUT OF THE ROCKIES. WHILE THE BEST FORCING/MOISTURE ASSOCIATED WITH THIS WILL REMAIN TO OUR SOUTH...SOME PCPN COULD SNEAK UP INTO AT LEAST SOUTHERN PORTIONS OF OUR FA EARLY IN THE WEEKEND. THIS MAY ALSO ALLOW FOR A SLIGHT MODIFICATION IN TEMPERATURES WITH HIGHS PUSHING INTO THE UPPER 50S TO LOWER 60S BY THE END OF THE LONG TERM PERIOD. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... LARGE SCALE UPPER LEVEL LOW CENTERED OVER THE WESTERN GREAT LAKES THIS MORNING WILL MOVE SLOWLY EAST THROUGH THE TAF PERIOD. EMBEDDED DISTURBANCES ROTATING AROUND THE LOW WILL AFFECT OUR REGION FROM TIME TO TIME. FOR TODAY...STRONG SURFACE LOW PRESSURE WILL REMAIN NORTH OF THE GREAT LAKES. MEANWHILE...A COLD FRONT WILL APPROACH THE REGION FROM THE WEST. THE INCREASING SURFACE PRESSURE GRADIENT COMBINED WITH DEEP MIXING WILL RESULT IN WINDY CONDITIONS FROM MID MORNING INTO EARLY EVENING. WINDS WILL VEER FROM A SOUTHWEST TO A WEST/SOUTHWEST DIRECTION WITH WIND GUSTS IN THE 30 TO 40 KNOT RANGE. MODELS CONTINUE TO INDICATE THAT SOME MOISTURE IN THE LOW TO MID LEVEL WILL DEVELOP/ADVECT NORTHEAST INTO THE REGION BY THIS AFTERNOON. THIS CLOUD LAYER COULD BECOME CONVECTIVE ENOUGH TO PRODUCE A FEW SPRINKLES OR LIGHT SHOWERS...MAINLY ALONG AND SOUTH OF THE OHIO RIVER. FOR TONIGHT...ONE OF THOSE EMBEDDED DISTURBANCES MENTIONED WILL DIG SOUTHEAST INTO OUR AREA. THIS FEATURE WILL TEAM UP WITH FRONTAL CONVERGENCE FROM THE ADVANCING COLD FRONT TO BRING A THREAT OF SHOWERS TO THE TAF SITES BETWEEN 06Z AND 12Z. THERE COULD BE SOME POCKETS OF MVFR VISIBILITIES ASSOCIATED WITH THE MORE ROBUST SHOWERS. OUTLOOK...GUSTY WEST TO NORTHWEST WINDS UP TO 30 KNOTS EXPECTED WEDNESDAY AFTERNOON INTO EARLY EVENING. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...WIND ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR OHZ026-034-035-042>046-051>056-060>062. KY...NONE. IN...WIND ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR INZ050. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...JGL AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS NORMAN OK
645 AM CDT TUE APR 21 2015 .DISCUSSION... AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW. && .AVIATION... THINK VFR CONDITIONS WILL MAINLY PREVAIL. ISO-SCT -SHRA WILL BE EAST OF KPNC-KOKC-KDUC BY 15Z. ISO-SCT TSRA WILL LIKELY DEVELOP OVER WESTERN OKLAHOMA AFTER 06Z...THUS ADDED VCTS AT TAF SITES IN THESE AREAS. BRIEF VARIABLE GUSTY WINDS...GS...AND MVFR OR LOWER CONDITIONS MAY BE POSSIBLE WITH TSRA. FAIRLY LIGHT SURFACE WINDS WILL SHIFT TO THE NORTH TO NORTHEAST AT MANY SITES AFTER 06Z. MVFR/IFR CONDITIONS MAY FORM SOUTH OF KWWR-KOUN AFTER 06Z. DID NOT MENTION THINKING THESE LOWER CONDITIONS WILL NOT FORM IN THESE LOCATIONS BEFORE 12Z WEDNESDAY. MBS && .PREV DISCUSSION... /ISSUED 358 AM CDT TUE APR 21 2015/ DISCUSSION... THE FORECAST CHALLENGE OF THE DAY IS SEVERE WEATHER POTENTIAL THROUGH FRIDAY. THIS MORNING...ISOLATED TO SCATTERED SHOWERS FROM WEAK MID LEVEL MOISTURE CONVERGENCE/ISENTROPIC LIFT WILL CONTINUE MAINLY ACROSS SOUTHERN OKLAHOMA. CANNOT RULE OUT A RUMBLE OF THUNDER...BUT NO SEVERE WEATHER WILL OCCUR. ANY RAINFALL WILL BE LIGHT AND UNDER 0.10 INCH. THIS AFTERNOON...SKIES WILL CLEAR AND ALLOW FOR GOOD DAYTIME HEATING. THINK CAPPING WILL BE TOO STRONG FOR STORM DEVELOPMENT...EXCEPT PERHAPS NEAR A WEAK SURFACE BOUNDARY OVER SOUTHERN KANSAS ACCORDING TO THE LATEST HRRR RUN. KEPT 20 PERCENT CHANCE FOR STORMS NEAR THE KANSAS AND OKLAHOMA STATE LINE EAST OF ALVA AFTER 4 PM. IF THESE STORMS FORM...THEY COULD BE SEVERE WITH SOME LARGE HAIL UP TO GOLF BALLS AND DAMAGING WINDS UP TO 60 MPH AS STRONG 0-6 KM SHEAR AND MUCAPE AROUND 1000 J/KG SUPPORT SOME SEVERE POTENTIAL. TONIGHT...WILL MONITOR FOR ADDITIONAL STORM FORMATION...MAINLY AFTER MIDNIGHT ACROSS WESTERN OKLAHOMA ON THE NOSE OF THE LOW LEVEL JET. LATEST MODELS HAVE BEEN TRENDING SLOWER WITH STORM DEVELOPMENT. WITH INCREASING ELEVATED INSTABILITY AND STRONG 0-6 KM SHEAR...STORMS WILL BEGIN WITH LARGE HAIL UP TO GOLF BALLS AS THE MAIN HAZARD...BUT MAY TRANSITION TO SOME WIND AND HAIL AS STORMS MAY FORM INTO A CLUSTER OR LINE THEN MOVE EAST OR SOUTHEAST TOWARDS DAYBREAK...MAINLY AFFECTING WESTERN OKLAHOMA. A FEW ADDITIONAL SEVERE STORMS MAY BE NEAR A DEVELOPING COLD FRONT IN NORTHERN OKLAHOMA. WIDESPREAD SEVERE SEEMS UNLIKELY TONIGHT. WEDNESDAY...AN ACTIVE DAY OF SEVERE WEATHER MAY OCCUR... ESPECIALLY ACROSS THE SOUTHERN HALF OF OKLAHOMA AND NORTH TEXAS. A COMPLEX OF STORMS MAY OCCUR DURING THE MORNING HOURS AND MOVE EAST OR SOUTHEAST BRINGING SOME WIND AND HAIL REPORTS AS WELL AS LOCALLY HEAVY RAINFALL. REDEVELOPMENT MAY OCCUR DURING THE AFTERNOON AND EVENING NEAR THE OUTFLOW BOUNDARY WHICH MAY BE NEAR THE RED RIVER. THERE IS SOME POTENTIAL FOR SIGNFICANT SEVERE INCLUDING GIANT HAIL GREATER THAN GOLF BALLS...DAMAGING WINDS OVER 70 MPH...AND PERHAPS TORNADOES IF LOW LEVEL SHEAR IS STRONG ENOUGH...BUT CONFIDENCE OF THIS OCCURRING REMAINS LOW AS NOT SURE HOW THE CONVECTION DURING THE MORNING AFFECTS THE ENVIRONMENT DURING THE AFTERNOON AND EVENING HOURS. IT APPEARS NORTHERN OKLAHOMA MAY NOT RECEIVE MANY STORMS OR SEVERE WEATHER WHERE THE AIR WILL BE COOLER AND MORE STABLE. WEDNESDAY NIGHT INTO THURSDAY...A FEW SEVERE STORMS MAY LINGER OVER FAR SOUTHERN OKLAHOMA AND NORTH TEXAS WITH LARGE HAIL... DAMAGING WINDS...AND HEAVY RAINFALL. HOWEVER...MOST STORMS MAY BE SOUTH OF THE RED RIVER...LEAVING BEHIND COOL AND STABLE CONDITIONS ACROSS OKLAHOMA. CONFIDENCE OF SEVERE STORMS DURING THIS TIME FRAME REMAINS LOW AS NOT SURE HOW WEDNESDAY/S CONVECTION CHANGES THE AIRMASS ACROSS THE REGION. WENT BELOW MODEL GUIDANCE TEMPERATURES. FRIDAY...ANOTHER ROUND OF SEVERE THUNDERSTORMS...POSSIBLY WITH SIGNIFICANT SEVERE...MAY RETURN TO THE AREA. VERY STRONG SHEAR/WINDS WOULD SUPPORT FAST MOVING SUPERCELLS. HOWEVER... MOISTURE AND INSTABILITY REMAIN QUESTIONABLE...ESPECIALLY AS CONVECTION OVER TEXAS MAY LIMIT THE NORTHWARD PROGRESS OF RICHEST MOISTURE AND HIGHEST INSTABILITY. REGARDLESS...WILL CLOSELY MONITOR. ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS ALONG WITH WINDY AND HOT WEATHER MAY FORM BEHIND A DRYLINE. SATURDAY THROUGH MONDAY...A QUIETER WEATHER PATTERN IS FORECAST WITH NEAR AVERAGE TEMPERATURES. MBS && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 77 54 69 54 / 20 20 50 40 HOBART OK 77 54 73 54 / 10 40 70 40 WICHITA FALLS TX 78 57 76 57 / 10 20 40 40 GAGE OK 79 49 66 46 / 10 40 40 30 PONCA CITY OK 78 49 64 47 / 20 30 30 30 DURANT OK 76 57 75 60 / 30 10 60 40 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 25/17/17
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
652 AM CDT TUE APR 21 2015 .AVIATION... /12Z TAFS/ CLEAR SKIES ARE IN PLACE AS UPPER LEVEL MOISTURE PUSHES TO THE EAST AND LIGHT WINDS FROM THE NORTHWEST AND NORTHEAST DOMINATE AT THE SURFACE. HOWEVER...THIS CONDITION IS FORECAST TO QUICKLY CHANGE THIS MORNING AS SOUTHERLY WINDS RETURN. MVFR CONDITIONS ARE EXPECTED ACROSS KSAT AND KSSF AROUND 14Z TO 16Z AS A POCKET OF LOW CLOUDS FORM ACROSS THE SAN ANTONIO METRO AREA. CLOUDS WILL INCREASE THROUGHOUT THE DAY AS GULF MOISTURE PUSHES NORTHWARD FOR THE RETURN OF MVFR CONDITIONS ACROSS AREA SITES THIS EVENING. AREA SOUNDINGS AND MOS GUIDANCE ARE SUGGESTING CIGS TO LOWER TO IFR/LIFR OVERNIGHT AS SATURATED AIR DOMINATES THE AREA. WINDS WILL BE FROM THE SOUTHEAST FOR THE MOST PARTS WITH SPEEDS OF 10 KNOTS AND GUSTING UP TO 21 KNOTS ACROSS KDRT THIS AFTERNOON. && .PREV DISCUSSION... /ISSUED 442 AM CDT TUE APR 21 2015/ SHORT TERM (TODAY THROUGH WEDNESDAY)... A WEAK UPPER LEVEL DISTURBANCE MOVED OVER THE AREA OVERNIGHT AND CLEARING SKIES ARE LEFT IN ITS WAKE. THE CLEARING SHOULD BE TEMPORARY AS A MOIST LAYER AT 850 HPA SHOULD SATURATE IN MANY AREAS. THE CLOUDS WILL PROBABLY BE SCT VARIABLE TO BKN SINCE THE MOISTURE LAYER APPEARS THIN. THUS WILL GO WITH SLIGHTLY ABOVE BLENDED GUIDANCE HIGHS TODAY. RAP SOUNDINGS SUGGEST A BREAKABLE CAP SHOULD THERE BE ENOUGH MOISTURE SO WILL CONTINUE WITH ISOLATED POPS. AN UPPER LOW CURRENTLY OVER SOUTHERN CA WILL CONTINUE TO CARVE DEEPER OVER THE BAJA PENINSULA THROUGH WEDNESDAY. DEEPENING MOISTURE WILL LEAD TO INCREASED RAIN CHANCES AND A FEW STRONG STORMS AND POSSIBLE SUPERCELLS AS NOTED IN THE SPC DAY 2 OUTLOOK. LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)... A FAIRLY LIGHT LOW LEVEL FLOW WEDNESDAY NIGHT INTO THURSDAY MEANS THAT THERE COULD BE SOME REMNANT OUTFLOW BOUNDARIES LEFT FROM WEDNESDAY STORMS TO BRING ADDITIONAL STORM FOCUS FOR THURSDAY AS THE UPPER LOW BEGINS TO LIFT INTO THE SOUTHERN ROCKIES. HIGHEST POPS OF THE WEEK ARE THUS SAVED FOR THURSDAY NIGHT INTO FRIDAY. THE EJECTION OF THE LOW INTO A SHALLOW TROUGH LEAVES SOME COVERAGE UNCERTAINTIES THIS FAR SOUTH...SO DO NOT WANT TO OVER-ADVERTISE THE SEVERE THREAT BEYOND A NOD IN THE HWO. POPS SHOULD LOWER SATURDAY INTO SUNDAY AS FLAT RIDGING ALOFT RETURNS. MOISTURE IS SUFFICIENT FOR STORMS...BUT EXPECT A STRONGER CAPPING INVERSION. ANOTHER LOW LATITUDE UPPER DISTURBANCE IS FORECAST BY THE GFS TO BRING RAIN AND STORMS BY MIDWEEK...BUT WILL KEEP WITH THE MORE CONSERVATIVE ECMWF UNTIL THE PATTERN DIFFERENCES BETWEEN MODELS DECREASE. TEMPERATURES THROUGH THE PERIOD SHOULD CONTINUE TO BE SEASONAL. A WEAK FRONT EXPECTED SATURDAY WILL PROBABLY ADD TO DAYTIME TEMPERATURES THROUGH REDUCED CLOUDINESS. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 80 66 82 69 86 / 20 10 30 30 20 AUSTIN BERGSTROM INTL AIRPORT 79 66 81 68 85 / 20 10 30 30 20 NEW BRAUNFELS MUNI AIRPORT 79 66 82 69 87 / 20 20 30 30 20 BURNET MUNI AIRPORT 77 66 81 68 85 / 20 20 30 30 20 DEL RIO INTL AIRPORT 81 67 86 70 88 / 20 20 20 10 20 GEORGETOWN MUNI AIRPORT 79 67 82 68 86 / 20 10 30 30 20 HONDO MUNI AIRPORT 82 67 82 69 87 / 20 20 30 20 20 SAN MARCOS MUNI AIRPORT 78 66 81 68 85 / 20 20 30 30 20 LA GRANGE - FAYETTE REGIONAL 79 66 82 70 85 / 20 10 30 30 20 SAN ANTONIO INTL AIRPORT 80 68 82 71 86 / 20 20 30 20 20 STINSON MUNI AIRPORT 81 68 82 71 87 / 20 20 30 20 20 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...17 SYNOPTIC/GRIDS...18
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
138 PM PDT TUE APR 21 2015 .SYNOPSIS... A COUPLE UPPER LEVEL DISTURBANCES MOVING THROUGH THE REGION TODAY THROUGH THURSDAY...IN ADDITION TO AN UNSTABLE ATMOSPHERE...WILL RESULT IN THE CHANCES FOR SHOWERS AND THUNDERSTORMS...MAINLY DURING THE AFTERNOON AND EARLY EVENING HOURS EACH DAY OVER THE MOUNTAIN AND DESERT AREAS. BEST CHANCES AND MOST WIDESPREAD SHOWER ACTIVITY EXPECTED ON THURSDAY...WHEN SCATTERED SHOWERS AND POSSIBLE THUNDERSTORMS MAY OCCUR OVER THE COAST AND VALLEY AREAS AS WELL. A THIRD DISTURBANCE MOVING THROUGH ON FRIDAY COULD BRING SOME LIGHT SHOWERS MAINLY TO AREAS OVER AND WEST OF THE MOUNTAINS. NIGHT AND MORNING STRATUS WILL PERSIST OVER THE COAST...VALLEY AND COASTAL SLOPE AREAS...WITH ONLY PARTIAL CLEARING AT BEST DURING THE DAY-TIME HOURS. DAY-TIME HIGH TEMPERATURES WILL FALL TO SEVERAL DEGREES BELOW NORMAL. ONSHORE FLOW WILL RESULT IN CONTINUED GUSTY WEST WINDS IN THE MOUNTAINS AND DESERTS. INCREASING HIGH PRESSURE ALOFT SATURDAY THROUGH MONDAY WILL BRING WARMING...DRYING CONDITIONS...AND A SHALLOW MARINE LAYER. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... VISIBLE SATELLITE INDICATES THAT MARINE LAYER STRATUS HAS NOT CLEARED OUT OF MOST COAST/VALLEY/COASTAL SLOPE AREAS THIS AFTERNOON. 12Z MIRAMAR SOUNDING SHOWS A MARINE LAYER INVERSION AT 4000 FEET. VISIBLE SATELLITE ALSO SHOWS SOME TOWERING CUMULUS/CUMULONIMBUS OVER THE RIVERSIDE AND SAN BERNARDINO COUNTY MOUNTAINS...AND THE HIGH DESERTS...WITH RADAR SHOWING SOME LIGHT SHOWERS IN THESE AREAS. RADAR WAS A LITTLE MORE ACTIVE IN THE LATE MORNING HOURS...WITH NUMEROUS LIGHTNING STRIKES OVER THE BIG BEAR LAKE AREA...AND SOME OVER THE RIVERSIDE MOUNTAINS AND COACHELLA VALLEY. THERE WAS ALSO A REPORT OF PEA SIZE HAIL IN BIG BEAR. THE SHOWERS AND THUNDERSTORMS WERE THE RESULT OF A VORTICITY MAX MOVING UP FROM THE SOUTH AROUND THE UPPER LOW CIRCULATION. HOWEVER...BARELY ANY MEASURABLE RAIN WAS REPORTED FROM THESE SHOWERS AND THUNDERSTORMS...WITH ONLY SOME 0.01 TO 0.02 INCH REPORTS. ACCORDING TO THE NAM12...THERE IS A SLIGHT INFLUX OF MID-LEVEL MOISTURE THAT OCCURS THIS AFTERNOON OVER WESTERN RIVERSIDE AND SOUTHWEST SAN BERNARDINO COUNTIES...WITH SURFACE BASED CAPE INCREASING TO 400-600 J/KG...LIFTED INDEX OF -2 TO -5 DEG C...MOVING THROUGH THESE AREAS AS THE UPPER LOW SITS OVER EXTREME SOUTHWEST CALIFORNIA. SURFACE HEATING MAY BE LIMITED OVER THE HIGH DESERTS AND SAN BERNARDINO MOUNTAINS DUE TO THE CLOUDY CONDITIONS IN THAT AREA AT THE MOMENT. THUS...THE RIVERSIDE AND SAN DIEGO COUNTY MOUNTAINS AND DESERTS MAY BE MORE FAVORED FOR AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS...AND THE 19Z HRRR DEPICTS THIS WELL. CHANCES FOR SHOWERS DIMINISH OVERNIGHT AS INSTABILITY FROM DAY-TIME SURFACE HEATING SHUTS OFF. FOR WEDNESDAY...ANOTHER...DEEPER TROUGH DEVELOPS OVER THE REGION...WITH SOME ADDITIONAL MID-LEVEL MOISTURE ADVECTION UNDER SOUTHWEST FLOW. DYNAMICS LOOK WEAKER...WITH NOT A LOT OF PVA... UPPER LEVEL DIVERGENCE OR LOW LEVEL CONVERGENCE OF WINDS INDICATED. INSTABILITY ALSO APPEARS TO BE A LITTLE LESS...WITH SURFACE BASED CAPE OF 100-500 J/KG AND LIFTED INDEX OF -1 TO -3 DEG C. HOWEVER...WITH THE DAY-TIME HEATING...SOME SHOWERS AND THUNDERSTORMS COULD DEVELOP OVER THE MOUNTAINS AND PORTIONS OF THE DESERTS DURING THE AFTERNOON AND EARLY EVENING HOURS. THE HI-RES MODELS DO SHOW MOUNTAIN AND HIGH DESERT CONVECTION BEING GENERATED GENERALLY IN THE SAME LOCATIONS AS TODAY...AND THE WEDNESDAY POPS REFLECT THAT. ON THURSDAY...THE TROUGH AXIS MOVES INLAND...BRINGING DEEPER MOISTURE THAN TUESDAY/WEDNESDAY...SLIGHTLY COLDER AIR ALOFT...AND A CONTINUED UNSTABLE ATMOSPHERE. DYNAMICS APPEAR TO BE STRONGER AS WELL...WITH BETTER PVA AND UPPER LEVEL DIVERGENCE INDICATED. HIGH- RES MODELS...PARTICULARLY THE CANSAC-WRF AND LOCAL WRF...SHOW THE MOST WIDESPREAD SHOWERS AND THUNDERSTORMS OCCURRING ON THIS DAY AS OPPOSED TO TUESDAY/WEDNESDAY. AS THE TROUGH MOVES INLAND...THE LOW- LEVEL MOIST LAYER LOOKS TO DEEPEN TO NEAR 7000-10000 FEET...WHICH...IN ADDITION TO THE DYNAMICS...COULD PRODUCE SCATTERED SHOWERS AND POSSIBLE THUNDERSTORMS OVER THE COAST AND VALLEY AREAS. FOR TODAY THROUGH THURSDAY...SNOW LEVELS LOOK TO BE AROUND 7000-8000 FEET...WITH A COUPLE INCHES OF SNOW POSSIBLE ABOVE THAT ELEVATION. OVERALL RAINFALL AMOUNTS WILL BE LIGHT...EXCEPT UNDERNEATH ANY HEAVY SHOWERS OR THUNDERSTORMS. SINCE WINDS ALOFT WILL GENERALLY BE WEAK...THE SHOWERS AND THUNDERSTORMS WILL LIKELY BE SLOW MOVING...AND SOME LOCALIZED MINOR FLOODING COULD OCCUR. AS FAR AS THE MARINE LAYER GOES...STRATUS WILL CONTINUE TO BE VERY DEEP...WITH NIGHT AND MORNING STRATUS MOVING DEEP INTO THE VALLEYS AND THE COASTAL SLOPES...AND ONLY PARTIAL CLEARING AT BEST DURING THE DAYS. ONSHORE FLOW AT THE SURFACE WILL RESULT IN GUSTY WEST WINDS IN THE MOUNTAINS AND DESERTS EACH DAY...STRONGEST ON THURSDAY WITH LOCAL GUSTS TO 55 MPH POSSIBLE THAT DAY. FINALLY...DAY-TIME HIGH TEMPERATURES WILL FALL TO 5-10 DEGREES BELOW NORMAL...AND LOCALLY 15 DEGREES BELOW NORMAL. THE TROUGH MOVES OFF TO THE EAST LATE THURSDAY NIGHT...WITH DIMINISHING SHOWER CHANCES GOING INTO FRIDAY MORNING. HOWEVER...SOME SHOWERS MAY CONTINUE TO OCCUR DURING THE DAY FRIDAY AS A NEW SHORT- WAVE TROUGH MOVES THROUGH. THESE SHOWERS ARE MOST LIKELY TO DEVELOP WITHIN THE LOW-LEVEL MOIST LAYER OVER AND WEST OF THE MOUNTAINS. A LACK OF INSTABILITY WILL LIKELY NOT RESULT IN THUNDERSTORMS ON THIS DAY. ANY PRECIP AMOUNTS WILL BE FAIRLY LIGHT. SATURDAY INTO NEXT MONDAY...HIGH PRESSURE WILL GRADUALLY DEVELOP OVER THE REGION...RESULTING IN WARMER...DRIER WEATHER. ONSHORE FLOW WILL CONTINUE FOR THE MOST PART...WITH A SHALLOW MARINE LAYER. DAY- TIME HIGHS LIKELY TO REACH ABOVE NORMAL BY MONDAY. && .AVIATION... 212000Z...COAST/VALLEYS...SCT/BKN LOW CLOUDS...WITH BASES 4000-5000 FEET MSL AND TOPS TO 6000 FEET MSL...WILL CONTINUE THROUGHOUT THE DAY AND LOCALLY OBSCURE HIGHER TERRAIN AT TIMES. STRATUS WILL QUICKLY BECOME OVC THIS EVENING FROM THE COAST TO THE COASTAL MOUNTAIN SLOPES...WITH BASES FROM 3000-4000 FT MSL AND TOPS NEAR 5000 FT MSL. LOW CLOUDS WEDNESDAY WILL SLOWLY BECOME SCT THROUGH WEDNESDAY AFTN. MTNS AND DESERTS...CLOUDS OVER MOUNTAIN CRESTS AND HIGH DESERTS THROUGH THIS EVENING. -SHRA/-TSRA CURRENTLY OVER THE HIGH DESERTS...WITH DEVELOPMENT POSSIBLE OVER THE MOUNTAIN CRESTS THROUGH THIS AFTERNOON. STORM BASES ARE NEAR 10 KFT WITH TOPS TO 25 KFT ...AND WILL BE CAPABLE OF PRODUCING GUSTY SFC WINDS AND SMALL HAIL. SHOWERS WILL END BY 02Z...WITH RESIDUAL HIGHER DEBRIS CLOUDS OVERNIGHT. ISOLATED AREAS OF BREEZY WEST WINDS THROUGH MTN PASSES...WITH GUSTS TO 40 KT...WILL BE POSSIBLE TONIGHT. && .MARINE... 130 PM...NO HAZARDOUS MARINE WEATHER IS FORECAST THROUGH SATURDAY. && .SKYWARN... SKYWARN ACTIVATION IS NOT ANTICIPATED TODAY. HOWEVER WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...HARRISON AVIATION/MARINE...JJT
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1230 PM CDT TUE APR 21 2015 .UPDATE... ISSUED AT 1012 AM CDT TUE APR 21 2015 MAIN FORECAST CONCERN WILL BE WITH THE WINDS TODAY. ALREADY STARTING TO SEE WIND GUSTS TO AROUND 30 MPH ACROSS THE NORTHERN CWA. LATEST HRRR AND RAP DATA SUGGESTING A PERIOD OF 40-45 KNOTS FOR A FEW HOURS EARLY THIS AFTERNOON ACROSS MAINLY AREAS ALONG AND NORTH OF I-74...ALTHOUGH THEY ARE ALSO NOW SUGGESTING THIS AS FAR SOUTH AS THE I-70 CORRIDOR. HAVE NOT GONE THAT HIGH SO FAR SOUTH AS CLOUDS THERE WILL BE ON THE INCREASE AND PREVENT FULL MIXING... BUT RAISED THE WIND GUSTS A TAD OVER THE NORTH AS MOSTLY SUNNY CONDITIONS CONTINUE INTO AT LEAST MID AFTERNOON. && .SHORT TERM...(TODAY) ISSUED AT 323 AM CDT TUE APR 21 2015 WINDY CONDITIONS WILL ONCE AGAIN DEVELOP ACROSS CENTRAL ILLINOIS TODAY, THANKS TO A TIGHTENING PRESSURE GRADIENT AND DEEP-LAYER MIXING. THE STRONGEST WINDS WILL BE FOCUSED ALONG/NORTH OF THE I-74 CORRIDOR, WHERE FORECAST SOUNDINGS SUGGEST SUSTAINED WINDS OF AROUND 30MPH WITH GUSTS UP TO 40MPH AT TIMES. WILL THEREFORE ISSUE A WIND ADVISORY FOR THIS AREA FROM 11AM TO 7PM. FURTHER SOUTH ACROSS THE REMAINDER OF THE KILX CWA, WINDS WILL REMAIN BELOW ADVISORY CRITERIA, MAINLY IN THE 25 TO 30MPH RANGE. SKIES WILL BE MOSTLY SUNNY THROUGH MUCH OF THE DAY, WITH AN INCREASE IN CLOUDS NOTED ACROSS THE FAR SOUTH DURING THE AFTERNOON AS A MID-LEVEL SHORT-WAVE APPROACHES FROM THE WEST. ALL MODELS ARE DEVELOPING SCATTERED SHOWERS/THUNDER IN ADVANCE OF THIS WAVE, BUT PRIMARILY KEEP THE ACTIVITY JUST SOUTH OF THE CWA. HIGHER-RES MODELS SUCH AS THE HRRR ARE SLIGHTLY FURTHER NORTH, SO HAVE OPTED TO INCLUDE SLIGHT CHANCE POPS FOR SHOWERS SOUTH OF I-70 THIS AFTERNOON. THANKS TO INCREASED SUNSHINE, HIGH TEMPERATURES WILL BE A FEW DEGREES WARMER THAN YESTERDAY, WITH READINGS CLIMBING INTO THE LOWER TO MIDDLE 60S. .LONG TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 323 AM CDT TUE APR 21 2015 MAIN CHALLENGES IN THE EXTENDED CONTINUE TO BE FROST POTENTIAL WEDNESDAY/THURSDAY NIGHTS, AS WELL AS, TIMING OF NEXT PRECIP EVENT BY THE END OF THE WEEK. DEEP UPPER LOW CURRENTLY CENTERED OVER THE WESTERN GREAT LAKES WILL BE THE DOMINANT WEATHER FEATURE ACROSS THE MIDWEST FOR THE NEXT FEW DAYS, RESULTING IN COOL CONDITIONS THROUGH FRIDAY. AS A PIECE OF ENERGY ROTATES AROUND THE LOW, A WEAK COLD FRONT WILL DROP THROUGH ILLINOIS TONIGHT. FORECAST SOUNDINGS ARE INITIALLY QUITE DRY: HOWEVER, THE LATEST MODELS SHOW QUITE A BIT MORE TOP-DOWN MOISTENING THAN IN PREVIOUS RUNS. AS A RESULT, THINK SCATTERED LIGHT SHOWERS WILL ACCOMPANY THE FRONT TONIGHT, WITH PERHAPS A FEW SHOWERS LINGERING INTO WEDNESDAY MORNING ACROSS THE FAR SE. ONCE THE FRONT EXITS, CANADIAN HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE MIDDLE AND END OF THE WEEK. THE RIDGE AXIS IS PROGGED TO BE JUST WEST OF THE MISSISSIPPI RIVER BY 12Z THURSDAY, SO AM EXPECTING WINDS TO DIMINISH CONSIDERABLY AS THE PRESSURE GRADIENT WEAKENS. WITH CLEAR SKIES AND LIGHT WINDS, OVERNIGHT LOWS WILL DIP INTO THE LOWER TO MIDDLE 30S, LEADING TO FROST DEVELOPMENT ACROSS MUCH OF THE AREA. IF SKIES REMAIN CLEAR, ANOTHER POTENTIALLY FROSTY NIGHT WILL OCCUR THURSDAY NIGHT AS WELL. FURTHER OUT, MODELS ARE HAVING CONSIDERABLE DIFFICULTY PINNING DOWN THE END OF THE WEEK SYSTEM. SOLUTIONS HAVE BEEN FLIP-FLOPPING FROM RUN TO RUN, SO OVERALL FORECAST CONFIDENCE BEYOND THURSDAY REMAINS LOWS. THE 00Z APR 21 GFS HAS MADE A MAJOR SHIFT BACK TO A SOLUTION IT FEATURED A COUPLE OF DAYS AGO. MEANWHILE, BOTH THE ECMWF AND GEM SEEM TO BE HEADING IN THE OPPOSITE DIRECTION. GIVEN SO MUCH MODEL INCONSISTENCY, PREFER TO MAKE VERY FEW CHANGES TO THE EXTENDED. WITH CANADIAN HIGH PRESSURE INITIALLY IN PLACE ACROSS THE MIDWEST ON WEDNESDAY/THURSDAY, STILL THINK A SLOWER ARRIVAL OF THE NEXT STORM SYSTEM MAKES SENSE. AS A RESULT, HAVE KEPT FRIDAY DRY DESPITE WHAT THE ECMWF AND GEM ARE ADVERTISING. HAVE INTRODUCED POPS FRIDAY NIGHT INTO SATURDAY AS A SYSTEM OVER THE DESERT SOUTHWEST GETS KICKED EASTWARD. STILL QUITE A BIT OF UNCERTAINTY CONCERNING HOW FAR NORTH PRECIP WILL SPREAD, BUT HAVE STUCK WITH PREVIOUS THINKING OF KEEPING HIGHEST POPS FOCUSED ACROSS THE SOUTHERN HALF OF THE CWA. THIS IS IN GOOD AGREEMENT WITH THE LATEST GFS, BUT NOT THE ECMWF/GEM WHICH BOTH FOCUS PRECIP MUCH FURTHER NORTH. ONCE THE SYSTEM EXITS, A RETURN TO DRY WEATHER IS ANTICIPATED FOR SUNDAY BEFORE ANOTHER FAST-MOVING NORTHERN-STREAM WAVE POTENTIALLY BRINGS A FEW SHOWERS BACK INTO THE PICTURE BY MONDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1230 PM CDT TUE APR 21 2015 STRONG WINDS GUSTING TO THE SURFACE NOW...WITH SOME GUSTS NEAR 35 KNOTS AT MIDDAY AROUND KPIA. STRONGEST WINDS EXPECTED IN THE KPIA-KCMI CORRIDOR THROUGH AFTERNOON WITH SEVERAL GUSTS 30-40 KNOTS...WITH GUSTS STARTING TO TAIL OFF TOWARD 00Z. HAVE SEEN SOME INCREASE IN DIURNAL CLOUDS AROUND 6000 FEET...AND VFR CONDITIONS EXPECTED TO PREVAIL...ALTHOUGH CEILINGS WILL THICKEN UP AFTER SUNSET. AREA OF RAIN SHOWERS WITH A FRONT WILL MOVE THROUGH CENTRAL ILLINOIS MID TO LATE EVENING...BUT A FAIR AMOUNT OF DRY AIR IS NOTED BELOW 4000 FEET ON FORECAST SOUNDINGS...SO WILL CONTINUE MENTION WITH VCSH FOR NOW. HOWEVER...CEILINGS SHOULD DROP CLOSER TO AROUND 3500-4000 FEET FOR SEVERAL HOURS...BEFORE RISING OVERNIGHT BEHIND THE FRONT. SOME GUSTY NORTHWEST WINDS EXPECTED AGAIN LATE WEDNESDAY MORNING...ALTHOUGH THESE SHOULD BE ABOUT 20 KNOTS OR LESS. && .ILX WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ027>031-037-038- 043>046. && $$ UPDATE...GEELHART SHORT TERM...BARNES LONG TERM...BARNES AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
113 PM EDT TUE APR 21 2015 .SYNOPSIS... ISSUED AT 107 PM EDT TUE APR 21 2015 STRONG WESTERLY WINDS WILL PERSIST THROUGH THE AFTERNOON WITH GUSTS AS HIGH AS 45 MPH. THERE IS ALSO A SLIGHT CHANCE FOR A FEW AFTERNOON RAIN SHOWERS...MAINLY ALONG AND NORTH OF THE TOLL ROAD. HIGHS TODAY WILL BE IN THE MID 50S WITH LOWS TONIGHT IN THE MID 30S. COOL AND DRY CONDITIONS WILL THEN CONTINUE THROUGH THE REST OF THIS WEEK. && .UPDATE... ISSUED AT 107 PM EDT TUE APR 21 2015 WIND ADVISORY GENERALLY ON TRACK WITH SEVERAL LOCATIONS SEEING EITHER SUSTAINED AND/OR GUSTS NEAR OR JUST ABOVE CRITERIA. FEW POCKETS UPSTREAM OF WIND GUSTS OVER 50 MPH WHICH MAY STILL MOVE IN MID TO LATE AFTERNOON AS A COLD FRONT SWEEPS THROUGH AND AIDS MIXING EVEN MORE. SCATTERED SHOWERS RAPIDLY DEVELOPED ACROSS FAR NE INDIANA INTO NW OHIO BUT ARE DEPARTING JUST AS FAST. ADDITIONAL SHOWERS ARE POSSIBLE ACROSS THE NE HALF OR SO OF THE AREA WITH A NUDGE SOUTHWARD IN POPS WARRANTED IN UPDATE. THE STRONGEST SHOWERS COULD PRODUCE SMALL HAIL AND LOCALLY INCREASE WIND SPEEDS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 356 AM EDT TUE APR 21 2015 STRONG WINDS WILL BE THE FORECAST MESSAGE OF THE DAY. STILL A DECENT HEIGHT/PRESSURE GRADIENT IN PLACE BETWEEN LARGELY BAROTROPIC LOW PRESSURE NEAR JAMES BAY AND ANTICYCLONE ACROSS THE GULF COAST. HOWEVER...THE REAL KEY FACTOR FOR GUSTY WINDS WILL BE VERY DEEP BOUNDARY LAYER MIXING. COMBINATION OF DRY AIR ADVECTION NEAR THE SURFACE...STRONG LATE APRIL SUN...AND VERY COLD CONDITIONS ALOFT WILL SET THE STAGE FOR MIXING HEIGHTS TO CLIMB TO AT LEAST 6 KFT WITH SOME MODELS (GFS AND RAP) SUGGESTING BOUNDARY LAYER DEPTHS WILL APPROACH 9 KFT. WIND SPEEDS AT THOSE LEVELS WILL BE IN THE 40-50 KT RANGE. NO DOUBT IT WILL BE WINDY BUT THE QUESTION IS WILL IT REACH ADVISORY CRITERIA (39KTS/45MPH). LACK OF GOOD ISENTROPIC DESCENT TO FORCE DOWN HIGHER MOMENTUM AIR IS CONCERNING...AS IS LACK OF ISALLOBARIC COMPONENT. ALWAYS SOME QUESTION AS TO HOW EFFICIENT TURBULENT MIXING ALONE WILL BE IN PRODUCING HIGHER GUSTS AT THE SURFACE....ESPECIALLY WHEN MIXING OVER SUCH A DEEP LAYER...AND NAM (AS WELL AS SOME OTHER HI-RES MODEL) SOUNDINGS ARE NOT QUITE AS BULLISH. THAT BEING SAID...MOST MODELS SHOW WIND SPEEDS AROUND 40 KTS AT THE TOP OF THE BOUNDARY LAYER AND SEVERAL INDICATE MIXING INTO SOME 50 KT WINDS. GIVEN THIS AND POTENTIAL FOR CONVECTIVE SHOWERS TO ENHANCE DOWNWARD MOMENTUM TRANSFER (SEE NEXT PARAGRAPH)...FEEL IT IS PRUDENT TO GO AHEAD AND PULL THE TRIGGER ON A WIND ADVISORY. EVEN IF MORE IMPRESSIVE GFS AND RAP FORECAST SOUNDINGS/WIND FIELDS DONT VERIFY...WILL STILL BE CLOSE TO ADVISORY CRITERIA. 500MB TEMPS BELOW -30C WILL SUPPORT A VERY DEEP LAYER OF STEEP LAPSE RATES DURING THE DAY TODAY. DEGREE OF MOISTURE AVAILABLE IS VERY MUCH IN QUESTION AND REMAINS A SIGNIFICANT LIMITING FACTOR FOR PRECIP DEVELOPMENT BUT SHREDS OF VORTICITY ROTATING AROUND LARGE CLOSED LOW COULD PROVIDE JUST ENOUGH MIDLEVEL CONVERGENCE/SATURATION TO WARRANT A FEW ISOLATED SPRINKLES/SHOWERS...MAINLY IN OUR NORTHERN COUNTIES. INHERITED FORECAST OF LOW CHANCE POPS ACROSS THE NORTH SEEMS REASONABLE. IF ANY SHOWERS DO MANAGE TO DEVELOP...STRONG NEGATIVE BUOYANCY DUE TO EVAPORATIONAL COOLING WITH "INVERTED V" SOUNDING COULD HELP MIX DOWN SOME HIGHER GUSTS. COULD ALSO BE SOME SMALL HAIL GIVEN COLD/DRY AIRMASS BUT VERY MARGINAL CAPE VALUES SUGGEST ANY SUBSTANTIVE UPDRAFTS WILL BE FEW AND FAR BETWEEN. SLIGHT CHANCE FOR SOME PRECIP LATE TONIGHT AS A MORE POTENT SHORTWAVE SWINGS THROUGH THE AREA. MOST MODELS KEEP LOW LEVEL FGEN RESPONSE JUST TO OUR SOUTH THOUGH AND WILL HOLD WITH A LOW CHANCE POP. DESPITE VERY COLD AIR ALOFT...TEMPS SHOULD RECOVER INTO THE MID 50S TODAY GIVEN DEEP MIXING. LOWS TONIGHT SHOULD GENERALLY HOLD IN THE MID 30S WITH STEADY WEST WINDS AND AT LEAST SOME CLOUDS KEEPING THE THREAT OF FROST LOW. && .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 356 AM EDT TUE APR 21 2015 NEG HGT ANOMALIES WILL PERSIST OVR SE CANADA THIS PD IN ASSOCN/W SLW EWD MEANDER OF DEEP CUTOFF FM THE LAKES THROUGH SE CANADA. THIS YIELDS A CONTN OF NW FLW ALOFT ACRS THE LAKES/OH VALLEY ALG W/MUCH BLO NORMAL TEMPS AND DRY WX THIS PD. HWVR POTENTIAL PITFALL EXISTS IN FRI NIGHT-SAT TIME FRAME W/BOTH HANDLING/PLACEMENT OF NWWD ORIENTED MID LVL TROUGH AXIS EXTENDING BACK INTO THE NRN PLAINS AND NEWD EJECTION OF SRN STREAM SW LOCATED OFF THE SRN CA COAST THIS MORNING. EC ELUCIDATED THIS POSSIBILITY FIRST LAST NIGHT AND NOW HAS GROWING SPRT FM GEM. THUS FELT IT PRUDENT TO PLACE SOME CONFIDENCE IN ALLBLEND GUIDANCE FOR THIS TIME PD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 107 PM EDT TUE APR 21 2015 DEEP MIXING OF STRONGER WINDS HAS BEEN A BIT SLOW TO MATERIALIZE AT KSBN...BUT STILL PLENTY TO CAUSE ISSUES. AT KFWA TAFS PRETTY MUCH ON TRACK. WINDS WILL SUBSIDE THIS EVENING BUT STILL REMAIN WESTERLY AND THEN PICK UP AGAIN ON WEDNESDAY. A FEW SHOWERS MAY PASS NEAR EITHER AIRPORT THROUGH LATE AFTERNOON...BUT LITTLE OVERALL IMPACT EXPECTED. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WIND ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR INZ003>009-012>018-020-022>027-032>034. MI...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MIZ077>081. OH...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ001-002-004-005- 015-016-024-025. LM...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 4 PM EDT WEDNESDAY FOR LMZ046. GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR LMZ046. SMALL CRAFT ADVISORY UNTIL 4 PM EDT WEDNESDAY FOR LMZ043. && $$ UPDATE...FISHER SYNOPSIS...AGD SHORT TERM...AGD LONG TERM...T AVIATION...FISHER VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1247 PM CDT Tue Apr 21 2015 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 300 AM CDT TUE APR 21 2015 Deep upper low over the Great Lakes was making slow eastward progress early this morning with likely a few small scale waves rotating around it through the Northern and Central Plains. Periodic mid cloud was present over the local area via isentropic upglide from rather brisk and backed mid level winds. At least minor amounts of EPV along the moist layer allowing some showers to form aloft, with weak returns on radar showing some very light precip reaching to the lower troposphere. HRRR and RAP runs quite similar to some 4km WRF runs with light precip forming over central Kansas in the next few hours, with latest IR imagery indicating recent cloud development there. All nearby 0Z soundings measured 850mb dewpoint depressions around 12C, making measurable amounts hard to imagine in this activity. A somewhat more unstable airmass develops over the southeast quarter of Kansas this afternoon with weak surface convergence. Will maintain small storm chances with still minor isentropic lift and weak wave potential in place. The stronger wind fields aloft could lead to some storm organization along with CAPE around 500 J/kg and dry adiabatic low level lapse rates to produce a very small threat for severe wind and hail in the mid afternoon to early evening. Areas outside of storms could also see a few rather strong wind gusts with mixing depths reaching 7000-10000ft AGL though some veering remains through the column. The still dry airmass and gusty winds lead to elevated fire danger in western locations this afternoon. Cold front via a stronger wave rotating around the low arrives this evening and makes quick south progress through the state tonight. Moisture, though modest, will continue to pool ahead of this front for some storm chances through much of the night in the southern zones, with typical diurnal trends allowing severe concerns to diminish. Models are allowing the boundary layer to decouple fairly quickly behind the front, but am somewhat skeptical of this given the baroclinic zone they advertise. If winds can fall quicker than expected, fairly clear skies could present a frost concern, but even if they do the window of cold and calm conditions for formation should be rather limited. Will mention patchy frost in far north where concern is highest. .LONG TERM...(Wednesday through Monday) Issued at 300 AM CDT TUE APR 21 2015 Eastern Kansas remains on the southwest side of an upper surface high for Wednesday, keeping high temperatures around 60 for most of the area. Have kept rain chances out of the southern areas with better chances south. Dry conditions continue Wednesday night into Thursday, with lows in the upper 30s to near 40 and highs climbing toward the middle 60s Thursday. Upper pattern starts to shift Thursday night as shortwave ridge noses out of the southern plains into our area, ahead of an upper trof lifting northeast out of the four corners region. Initial sensible weather impacts should be warmer lows in the 40s near 50 Thursday night with some showers possible after midnight as low level jet makes a return over the area. Latest EC appears to be trending toward the GFS solution for this shortwave as it moves into the plains, taking a faster track and developing the warm front from the surface low out into eastern or southeast Kansas. GFS keeps the boundary south of the area and would make for cloudy cool and rainy conditions area wide for Friday and Saturday night, and with EC solutions also trending this way, have gone with forecast as such. Southern branch of the upper jet takes the shortwave trof east of the area rather quickly on Saturday, with rain ending sometime during the morning hours. Cooler high pressure once again noses into the area behind the departing low and holds temperatures in the low 60s, followed by overnight lows in the 40s. Highs on Sunday rise a bit more into the middle 60s, and have kept rain chances relegated to north and west while surface high continues over the east. Another front progged to move across the area Sunday night with northwest flow aloft returning on Monday. Current forecast is for highs near 70, but this will depend on how strong the front and wave are as to how much cooler air it does, or does not, bring southward. && .AVIATION...(For the 18Z TAFs through 18Z Wednesday Afternoon) Issued at 1245 PM CDT TUE APR 21 2015 VFR conditions are expected the entire period with gusty winds throughout the afternoon. Mid-level clouds will move south over the area tonight as a frontal passage veers E winds N/NE after 04Z. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...65 LONG TERM...67 AVIATION...Heller
AREA FORECAST DISCUSSION
NWS PADUCAH KY
216 PM CDT TUE APR 21 2015 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 215 PM CDT TUE APR 21 2015 NEAR TERM ON TRACK...AS CONVECTION CONTINUES TO TAKE SHAPE OVER SOUTHERN INTO SOUTHEAST MISSOURI...LIGHTNING NOW OBSERVED WEST OF OUR CWFA. WILL CONTINUE TO MONITOR FOR THE POSSIBILITY OF SOME HAIL AND GUSTY WINDS GIVEN THE STEEP LAPSE RATES AND LOW FREEZING LEVELS...DESPITE LACK OF LOW LEVEL MOISTURE. THE CHANCES WILL CONTINUE THROUGH THE OVERNIGHT AS A BOUNDARY SETTLES SOUTH ACROSS THE REGION. WILL DIMINISH POPS FROM NW TO SE WEDNESDAY MORNING...DRY BY AFTERNOON. WILL KEEP IT DRY WEDNESDAY NIGHT THROUGH THURSDAY WITH WEAK HIGH PRESSURE ANGLING IN FROM THE UPPER MIDWEST. CHANCES OF SHOWERS MAY EXIST JUST SOUTH OF THE AREA NEAR OUR CWFA BORDER. CAN ADJUST IF NEED BE. TEMPS A BLEND OF MOS AND EXISTING NUMBERS. NAM HIGH RES AND HRRR A REASONABLE APPROACH FOR CONVECTIVE TRENDS THROUGH 06Z. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 215 PM CDT TUE APR 21 2015 THE OPERATIONAL MODELS ARE TRYING TO FALL SOMEWHAT IN LINE WITH PRIOR ENSEMBLE MEAN SOLUTIONS THROUGH SUNDAY. ALL IN ALL... CONFIDENCE CONTINUES TO INCREASE FOR THE FIRST SYSTEM FRIDAY THROUGH SATURDAY. UPPER TROF SHOULD EJECT NE INTO THE PLAINS BY 00Z SAT WITH MOISTURE QUICKLY SPREADING EAST BY FRIDAY AFTERNOON AND EVENING. S/WV RIDGE AHEAD OF THE TROF NOT STRONG ENOUGH TO WARD OFF ONCOMING SHRA/TSRA CHANCE. SO WE ARE ON THE AGGRESSIVE SIDE OF THE ENVELOPE. LIKELY POPS STILL IN PLAY FOR FRIDAY NIGHT WITH CHANCE TO LOW END LIKELY SATURDAY AS WELL...AS THE UPPER TROF WEAKENS...AND THE REMNANT ENERGY TURNS ESE ACROSS THE AREA SATURDAY...CONTINUING THE CHANCE OF CONVECTION. SURFACE BOUNDARY SHOULD STAY JUST TO OUR SOUTH...SO ESSENTIALLY ELEVATED CONVECTION. CHANCES TAIL OFF SATURDAY NIGHT WITH A DRY FORECAST IN PLACE FOR SUNDAY. FOR MONDAY THROUGH TUESDAY...THE ENSEMBLE MEAN SOLUTIONS WERE UTILIZED AND OPERATIONAL MODELS THROWN OUT. A HIGHLY COMPLEX PATTERN IS FORECAST TO EVOLVE WITH SOME KIND OF A TROUGH EAST OF THE PLAINS AND RIDGE WEST. HOWEVER THERE IS TOO MUCH VARIABILITY IN THE DETAILS TO SIDE WITH ANY OPS SOLUTION AT THIS POINT. ITS GOING TO CHANGE. WE FEE COMFORTABLE MAINTAINING LOW CHANCE POPS FOR SHOWERS GIVEN THE UNSETTLED LOOK TO THE PATTERN. TEMPS WERE A BLEND OF BASE MODEL OUTPUT AND EXISTING FORECAST NUMBERS. && .AVIATION... ISSUED AT 1225 PM CDT TUE APR 21 2015 FIRST ITEM OF CONCERN THIS FORECAST PERIOD IS THE GUSTY SOUTHWEST WINDS. THEY WILL CONTINUE GUSTING UP TO AROUND 25 MPH AT TIMES FOR THE REST OF THE AFTERNOON...WITH THE GUSTS SUBSIDING AFTER 00-02Z. ALL INDICATIONS ARE THAT CONVECTION WILL DEVELOP AFTER 18Z AND LAST THROUGH THE EVENING...WITH GREATEST PROBABILITIES OVER THE KCGI/KPAH AREAS. ACTIVITY WILL BE RATHER SCATTERED...I.E. SHOULD BE ABLE TO FLY AROUND...SO OPTED FOR JUST A VCTS. WILL UPGRADE TO A TEMPO GROUP IF STORMS BECOME MORE ORGANIZED/WIDESPREAD. GUSTY WINDS WILL BE POSSIBLE IN THE STRONGER STORMS. A FRONTAL BOUNDARY WILL BE ADVANCING FROM THE NORTH LATER TONIGHT INTO EARLY TOMORROW MORNING. THIS WILL BE FOCUS FOR MORE CONVECTION AND POSSIBLY LOWER CIGS. THE FRONT WILL ALSO BRING A WIND SHIFT AROUND TO THE WEST/NORTHWEST. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
352 PM EDT TUE APR 21 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 352 PM EDT TUE APR 21 2015 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO OVER THE UPR LKS DOWNSTREAM OF HI AMPLITUDE UPR RDG OVER WRN NAMERICA. COMBINATION OF DEEP CYC FLOW W TO NW FLOW AND INSTABILITY ENHANCED BY DAYTIME HEATING UNDER ACCOMAPANYING THERMAL TROF /12Z H5 TEMP AT GRB WAS -31C/ AND DEEP MSTR SHOWN ON THE 12Z RAOBS IS RESULTING IN SCT-NMRS SN SHOWERS THAT ARE MIXED WITH RA IN THE WARMER LOCATIONS. BUT COLDER CLD TOP TEMPS/MORE WIDESRPEAD SN SHOWERS ARE CONFINED MAINLY TO NW ONTARIO/FAR NRN MN IN AREA WHERE MODELS INDICATE DEEP QVECTOR CNVGC. MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON POPS AND POTENTIAL SN ACCUMS ASSOCIATED WITH DEEP CYC...MOIST NW FLOW ARND SLOW MOVING CLOSED LO TO THE NE OF UPR MI. CLOSED LO CENTERED OVER ERN LK SUP THIS AFTN IS FCST TO DRIFT SLOWLY TO THE NE AND TO JUST S OF JAMES BAY ON WED. ALTHOUGH ACCOMPANYING DEEP LYR QVECTOR CNVGC THAT IS SUPPORTING COLDER CLD TOPS TO THE NW IS FCST TO REMAIN TO THE N OF UPR MI...PERSISTENT MOIST...CYC NW FLOW ARND THIS FEATURE WL MAINTAIN AT LEAST CHC POPS OVER THE CWA THRU WED...WITH THE LOWER POPS GENERALLY OVER THE SCENTRAL AND THE HIER POPS OVER THE HIER TERRAIN OF THE NW WITH UPSLOPE WIND COMPONENT. BUT LOSS OF DAYTIME HEATING TNGT WL CAUSE THE CHARACTER OF THE SHOWER PATTERN TO TRANSITIONS FM ONE THAT SUPPORTS THE HIER POPS OVER THE INTERIOR THIS AFTN TO A MORE WINTRY LES LOOK TNGT. IN FACT...THE NW FLOW IS PROGGED TO ADVECT H85 TEMPS AS LO AS -13 TO -14C OVER THE KEWEENAW BY 12Z WED...TEMPS LO ENUF TO SUPPORT LES AND INCRS SN/WATER RATIOS ONCE THE EFFECT OF DAYTIME INSOLATION HAS FADED. OVER THE HIER TERRAIN OF THE W...THERE WL LIKELY BE SEVERAL INCHES OF WET SN ACCUM TNGT INTO WED MRNG EVEN IN THE ABSENCE OF SGNFT LARGER SCALE FORCING. OPTED TO ISSUE AN SPS TO ALERT THE PUBLIC TO THE POTENTIAL OF SOME SLUSHY SN ACCUMS ON ROADS LATER THIS EVNG INTO WED MRNG. DAYTIME HEATING ON WED WL BRING ABOUT A RETURN TO A MORE LAND BASED INSTABILITY SHOWER PATTERN. BUT SOMEWHAT HIER HGTS/SHARPENING MID LVL INVRN FARTHER FM THE SLOWLY DEPARTING CLOSED LO THAT RESTRICTS DESTABILIZATION WL TEND TO LIMIT COVERAGE/INTENSITY OF THE SHOWERS AS COMPARED TO TODAY. ALTHOUGH H85 TEMPS ARE FCST TO MODERATE TO -10C TO -12C...MAX TEMPS ON WED WL HOLD IN THE 30S EXPECT WHERE SOME DOWNSLOPE WARMING AIDS DIURNAL TEMP RECOVERY INTO THE LO 40S OVER THE SCENTRAL. THERE COULD BE SOME RECORD LO MAX TEMPS ON WED. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 305 PM EDT TUE APR 21 2015 THE UPPER LOW THAT IS CURRENTLY AFFECTING THE AREA WILL SHIFT EAST INTO THE CANADIAN MARITIMES SHORTLY AFTER THE START OF THE LONG TERM PERIOD. THIS WILL LEAVE THE AREA BETWEEN THAT UPPER LOW AND AN UPPER RIDGE IN THE CENTRAL/SOUTHERN PLAINS. THUS...THE AREA WILL BE UNDER NORTHWESTERLY FLOW ALOFT FOR MOST DAYS THROUGH THE UPCOMING WEEKEND. WITH A SURFACE RIDGE STRETCHING SOUTH FROM A HIGH IN NORTHERN CANADA MOVING INTO THE AREA BY FRIDAY AND FRIDAY NIGHT...EXPECT DRIER AIR TO GRADUALLY MOVE INTO THE REGION AND DIMINISH THE PRECIPITATION POTENTIAL AND LEAD TO A DRY WEEKEND (ALTHOUGH THERE ARE HINTS OF A WEAK DISTURBANCE BRINGING AN ISOLATED SHOWER TO THE FAR WESTERN U.P. LATE FRIDAY NIGHT INTO SATURDAY MORNING). WITH THE MAIN UPPER LOW SHIFTING EAST...TEMPERATURES WILL SLOWLY WARM BUT STILL STAY BELOW NORMAL FOR LATE APRIL (AIDED BY THE LIGHT NORTHERLY FLOW OFF LAKE SUPERIOR). HEADING INTO NEXT WEEK...THE UPPER LOW CURRENTLY OVER THE GULF OF ALASKA WILL MOVE INTO THE PACIFIC NORTHWEST OVER THE NEXT 24-48HRS AND THEN INTO THE CENTRAL CONUS ON MONDAY. AS THE WAVE CONTINUES EAST...IT WILL INTERACT WITH THE UPPER LOW NEAR THE CANADIAN MARITIMES AND RE-ESTABLISH THE UPPER TROUGH OVER THE EASTERN CONUS. THIS WILL KEEP BELOW NORMAL TEMPERATURES IN PLACE INTO NEXT WEEK AND POSSIBLY LEAD TO SOME SHOWERS AROUND THE GREAT LAKES REGION. OVERALL...FAIRLY COOL AND QUIET END TO APRIL WITH NO HAZARDOUS WEATHER EXPECTED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 147 PM EDT TUE APR 21 2015 EXPECT SCT -SHSN...MIXED WITH RA AT THE WARMER SAW LOCATION...THIS AFTN IN PERSISTENT CHILLY...MOIST AND GUSTY NW FLOW ARND LO PRES IN ONTARIO ALONG WITH PREDOMINANT MVFR CONDITIONS. BEST CHC FOR SOME HEAVIER SHSN/AT LEAST OCNL IFR CONDITIONS WL BE AT IWD WITH FVRBL UPSLOPE FLOW. SAW HAS THE BEST CHC FOR VFR WX WITH A DOWNSLOPE WIND COMPONENT. AS COLDER AIR ARRIVES TNGT...THE SHSN WL TEND TO INCREASE IN COVERAGE AT CMX/IWD WITH USPLOPE NW WIND COMPONENT. PREDOMINANT IFR TO OCNL MVFR VSBYS WL THE RULE AT THESE LOCATIONS INTO WED MRNG...WHEN THE SHSN WL TEND TO BECOME MORE SCT AND ALLOW FOR IMPROVING OVERALL CONDITIONS. DOWNSLOPE NATURE OF THE NW FLOW WL LIMIT THE POTENTIAL FOR LOWER VSBYS AT SAW...BUT MVFR CIGS SHOULD PREVAIL THERE WITH LINGERING LLVL MSTR. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 305 PM EDT TUE APR 21 2015 NORTHWESTERLY WINDS UP TO 30 KNOTS WILL CONTINUE OVER LAKE SUPERIOR THROUGH THURSDAY MORNING. THERE COULD BE A FEW PERIODS OF GALE FORCE GUSTS TO 35KTS LATE TONIGHT INTO WEDNESDAY...BUT THEY SHOULDN/T BE WIDESPREAD. HIGH PRESSURE WILL BEGIN TO BUILD INTO WESTERN LAKE SUPERIOR THURSDAY AFTERNOON/NIGHT AND LEAD TO GRADUALLY DIMINISHING WINDS INTO FRIDAY. LIGHT NORTHERLY WINDS UP TO 15KTS ARE EXPECTED THIS WEEKEND. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...SRF AVIATION...KC MARINE...SRF
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1236 PM CDT TUE APR 21 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 355 AM CDT TUE APR 21 2015 AN ARCTIC COLD FRONT ACROSS NORTH DAKOTA WILL BACK INTO THE FCST AREA THIS AFTN PRODUCING SOME CLOUDINESS. THE FRONT WILL CONTINUE TO MOVE SOUTH AND WEST TONIGHT. BY 12Z WEDNESDAY A SMALL AREA OF HIGH PRESSURE HAS SETTLED OVER NCNTL NEB WHICH SHOULD PRODUCE LOWS IN THE 20S. BY THIS TIME...THE MODELS SUGGEST ANY CLOUD COVER WOULD LIE ACROSS THE PANHANDLE AND SOUTHWEST NEB WHICH WOULD HOLD UP LOWS IN THE LOWER 30S. HIGHS TODAY RISE INTO THE 60S AHEAD OF THE FRONT WITH 50S NORTH OF THE FRONT ALONG HIGHWAY 20. THE MIDLEVEL CLOUD COVER ACROSS CNTL/SERN NEB EARLY THIS MORNING IS ASSOCIATED WITH 700MB FRONTOGENESIS. THE RAP MOVES THESE CLOUDS SOUTHEAST AND THEN DROPS A SECOND BATCH OF CLOUDS INTO NRN NEB AS EARLY AS 15Z WHICH HANG AROUND MOST OF THE DAY AND THEN MOVE SOUTH AND WEST TONIGHT. THE RADAR RETURNS ACROSS NORTH DAKOTA MOVE EAST OF THE FCST AREA IN THE NAM MODEL WHILE THE HRRR SHOWS TOO MUCH DRY AIR IN THE LOWER LEVELS FOR ANYTHING MORE THAN SPRINKLES THIS AFTN AND TONIGHT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 355 AM CDT TUE APR 21 2015 SURFACE HIGH PRESSURE QUICKLY FOLLOWS THE COLD FRONT AND WILL SLIDE SOUTHEAST OF THE AREA EARLY IN THE DAY ON WEDNESDAY WITH SOUTHERLY WINDS DEVELOPING. DESPITE SOUTHERLY WINDS...COOL AIR ALOFT...850 TEMP FROM 3C EAST TO 8C WEST...AND EVEN WITH SUN AND GOOD MIXING...HIGHS IN THE UPPER 50S AND LOWER 60S. MEANWHILE AN UPPER LEVEL LOW LIFTS TOWARDS THE DESERT SW. MODELS ALSO SHOW A WEAK SYSTEM AHEAD OF THE MAIN LOW...PUSHING ACROSS THE SOUTHERN PLAINS. A SECOND WAVE EJECTS FROM THE MAIN LOW AND ARRIVES TO THE SOUTHERN/CENTRAL PLAINS WED NIGHT INTO THURSDAY. MARGINAL LIFT INTO SW NEB MAY RESULT IN A FEW LIGHT SHOWERS INITIALLY. A BETTER CHANCE ARRIVES LATER IN THE DAY ON THURSDAY AFTER WE GET SOME HEATING. MODELS INCREASE CAPES TO A FEW 100 J/KG AND LIFTED INDEX VALUES AROUND ZERO OR SLIGHTLY NEG. GENERALLY THING ACTIVITY WILL BE SOME SHOWERS AND A FEW RUMBLES OF THUNDER HERE OR THERE. BY FRIDAY THE MAIN LOW WILL BE CROSSING THE ROCKIES. MOISTURE CONTINUES TO INCREASE AHEAD OF THE LOW AND FRIDAY LOOKS TO SEE A WAVE OR TWO OF SHOWERS TO ROTATE THROUGH THE AREA. BETTER MOISTURE LIFT ASSOCIATED CLOSER TO THE LOW...WHICH FAVORS HIGHER POPS ACROSS SW NEB. A SECOND WAVE...CLIPPER...QUICKLY FOLLOWS FOR THE WEEKEND. SHOULD SEE A BRIEF BREAK IN THE ACTIVITY BEFORE THE SECOND WAVE ARRIVES...ALTHOUGH TIMING THE BREAK IS DIFFICULT DUE TO MODEL DIFFERENCES. FORECAST DOES RETAIN LOW POPS AND EXPECT THIS TO CHANGE IN THE COMING DAYS AS THE LULL IN ACTIVITY BECOMES MORE CLEAR. AT THIS TIME MODELS ARE IN FAVOR OF THE DRY PERIOD TO OCCUR SOMETIME SATURDAY...EARLIEST IS THE GEM/GFS...WHILE LATER IS FAVORED BY THE ECMWF. THE NEXT WAVE SHOULD BE EAST OF THE AREA TO START THE WORK WEEK DRY AND MILD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1235 PM CDT TUE APR 21 2015 A WEAK COLD FRONT WILL SLOWLY DROP THROUGH THE AREA THIS AFTERNOON...SWITCHING WESTERLY WINDS TO THE NORTH. WITH GOOD MIXING...NORTH TO NORTHWEST WINDS WILL BE 20-25 KTS AND GUSTY. OTHERWISE...VFR CONDITIONS WILL PREVAIL THROUGH WEDNESDAY MORNING. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...UNR-SR
AREA FORECAST DISCUSSION
NWS MEDFORD OR
257 PM PDT TUE APR 21 2015 .SHORT TERM...VISIBLE SATELLITE SHOWS THE ATMOSPHERE HAS DESTABILIZED AS EXPECTED WITH NUMEROUS CUMULUS BUILDUPS OVER THE HIGHER TERRAIN AND EAST SIDE. RADAR IS ALREADY SHOWING RETURNS IN EASTERN SISKIYOU, NORTHERN KLAMATH, AND CENTRAL LAKE COUNTIES. THERE HAS EVEN BEEN A STRIKE OR TWO RECORDED IN EASTERN SISKIYOU COUNTY JUST WEST OF TENANT. AND NUMEROUS STRIKES RECORDED JUST SOUTH OF THE CWA IN LASSEN COUNTY. HI- RES, NEAR TERM MODELS LIKE THE HRRR (HIGH RESOLUTION RAPID REFRESH) SHOW MOST OF THE ACTION OVER MODOC, LAKE, AND FAR EASTERN KLAMATH COUNTIES LATER THIS AFTERNOON. STEERING WINDS ARE FAIRLY LIGHT SO THESE STORMS WILL LIKELY BE SLOW MOVERS RESULTING IN THE POTENTIAL FOR SOME HEAVIER DOWNPOURS UNDER THE CORE OF THESE STORMS. ALSO EXPECT SOME GUSTY OUTFLOW WINDS WITH THE STRONGER STORMS ALONG WITH THE POTENTIAL FOR SMALL HAIL. MODELS CONTINUE TO SHOW THE ATMOSPHERE STABILIZING WITH THE LOSS OF DIURNAL HEATING SO CONVECTION SHOULD DIMINISH BY TONIGHT. THE ATMOSPHERE WEST OF THE CASCADES IS MORE STABLE WITH WEAKER LAPSE RATES SO NOT EXPECTING ANY THUNDERSTORMS FOR THAT AREA. ASIDE FROM THE RAIN EXPECTED WITH THE CONVECTION PREVIOUSLY MENTIONED, MOST AREAS WILL REMAIN DRY WITH THE PASSAGE OF THE COLD FRONT. WINDS WILL BE QUITE BREEZY THROUGH THE AFTERNOON IN RESPONSE TO THIS COLD FRONT MOVING THROUGH THE AREA. THE UPPER LEVEL TROUGH MOVES THROUGH OVERNIGHT INTO TOMORROW AND DRIER, MORE STABLE AIR MOVES IN BEHIND IT FOR WEDNESDAY. WEAK RIDGING STARTS TO BUILD OVER THE AREA WEDNESDAY NIGHT, BUT THIS IS SHORT LIVED AS A WEAK TROUGH APPROACHES THE AREA THURSDAY MORNING. THERE IS A CHANCE FOR SOME SHOWERS THURSDAY AFTERNOON, BUT THIS LOOKS MOSTLY CONFINED FROM THE UMPQUA DIVIDE AND NORTH. AN UPPER LOW MOVES IN OVER BRITISH COLUMBIA THURSDAY EVENING AND SHORTWAVES ROTATING AROUND IT CONTINUE THE CHANCE FOR PRECIPITATION FOR MOST OF THE AREA THROUGH SATURDAY MORNING. .LONG TERM...SATURDAY THROUGH TUESDAY...THE OPERATIONAL EC AND GFS ARE IN SIMILAR AGREEMENT WITH THE OVERALL PATTERN FRIDAY INTO NEXT WEEKEND. HOWEVER THERE IS DISAGREEMENT WITH THE PLACEMENT AND STRENGTH OF THE UPPER LOW FRIDAY. THE EC IS STRONGER AND FURTHER SOUTH WITH THE UPPER LOW AND WETTER. HAVE KEPT IN A CHANCE OF SHOWERS FOR MOST OF THE FORECAST AREA...THOUGH RAIN AND MOUNTAIN SNOW AMOUNTS SHOULD BE LIGHT. THE TROUGH AXIS SHIFTS EAST FRIDAY NIGHT AND RIDGING WILL ATTEMPT TO MOVE IN FROM THE SOUTHWEST. THE GFS SHOWS MORE OF A DIRTY RIDGE SCENARIO WITH WARM FRONTAL PRECIPITATION MOVING INTO THE AREA. THE EC HAS A MORE PRONOUNCED RIDGE AND THUS SHOWS A DRY AND MILDER SOLUTION. SUSPECT THE WARM FRONTAL PRECIPITATION IS OVERDONE, BUT DID NOT WANT TO DISCOUNT IT COMPLETELY, SO WITH WITH A BLEND BETWEEN THE EC AND GFS WITH A SLIGHTLY DRIER BIAS. A DIRTY RIDGE REMAIN OVER THE AREA SUNDAY WITH THE BEST CHANCE FOR PRECIPITATION OVER THE NORTHERN PART OF THE CWA. ESPECIALLY WEST OF THE CASCADES AND NORTH OF THE UMPQUA DIVIDE. SIGNIFICANT UPPER TROUGHING THAT`S BEEN HANGING OVER THE NORTHEAST PACIFIC FINALLY REACHES THE FORECAST AREA WITH SIGNIFICANT RAIN POTENTIALLY MONDAY INTO TUESDAY. THAT SAID...THERE IS SOME UNCERTAINTY AS TO WHEN THIS TROUGHING REACHES THE AREA. ENSEMBLE MEMBERS ARE OUT OF PHASE...BUT NOT AS MUCH AS YESTERDAY WITH THE TROUGH AXIS STARTING TO DROP SOUTH. IN CONTRAST, THE OPERATIONAL EC SHOWS MORE OF A SPLIT FLOW PATTERN NEAR 150 W AND MORE RIDGING IN OUR AREA, THUS DELAYING ANY SIGNIFICANT PRECIPITATION. IN SHORT...CONFIDENCE IS LOW TO MODERATE IN THE EXTENDED PERIOD AND DID NOT MAKE ANY SIGNIFICANT CHANGES. && .AVIATION...FOR THE 21/18Z TAF CYCLE...MVFR CONDITIONS WITH TERRAIN OBSCURATIONS ARE EXPECTED FROM THE UMPQUA BASIN AND COASTAL MOUNTAINS WESTWARD INTO TONIGHT. FURTHER INLAND GUSTY NORTHWEST WINDS WILL DEVELOP THIS AFTERNOON THROUGH THIS EVENING WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS EXPECTED FROM THE OREGON CASCADES AND CALIFORNIA TRINITY ALPS EASTWARD. IT`S POSSIBLE THUNDERSTORMS COULD RESULT IN TEMPORARY MVFR CIGS WITH MOUNTAINS PARTLY OBSCURED BETWEEN 23Z AND 04Z. -PETRUCELLI && .MARINE...UPDATED 300 PM PDT TUESDAY APR 21, 2015...HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT BUT THIS WILL RESULT IN GUSTY NORTH WINDS AND STEEP TO VERY STEEP SEAS. GALES AND WARNING LEVEL SEAS ARE EXPECTED AT TIMES SOUTH OF CAPE BLANCO TONIGHT THROUGH WEDNESDAY NIGHT. THURSDAY THROUGH THE WEEKEND...A SERIES OF FRONTAL SYSTEMS IS LIKELY TO MOVE THROUGH WITH BUILDING SWELL. NORTHWEST WINDS WEDNESDAY NIGHT THROUGH FRIDAY ARE EXPECTED TO BECOME SOUTHWESTERLY THIS WEEKEND. SPILDE && .FIRE WEATHER....FIRE WEATHER...UPDATED 3 PM PDT TUESDAY, APRIL 21ST, 2015... THE ATMOSPHERE IS ALREADY STARTING TO BECOME UNSTABLE AHEAD OF A RATHER SHARP, BUT NOT STRONG, INCOMING TROUGH OF LOW PRESSURE. A FEW ISOLATED STORMS HAVE DEVELOPED IN NORTHERN CAL AND NORTHERN KLAMATH COUNTY NORTHEAST OF CHEMULT. THE LATEST HRRR REFLECTIVITY PRODUCT SHOWS MOST OF THE ACTIVITY DEVELOPING IN NORTHERN CAL, THEN MIGRATING NORTH INTO PARTS OF LAKE AND KLAMATH COUNTIES LATE THIS AFTERNOON THROUGH THIS EVENING. UNLIKE THE HIGH IMPACT LIGHTNING EVENTS THAT SOMETIMES AFFECT OUR REGION MAINLY IN THE SUMMER, FORCING WITH THE INCOMING SYSTEM IS WEAK IN THAT THERE IS NO CLEAR COLD POOL MOVING THROUGH. INSTEAD, A WEAK SURFACE FRONT IS EXPECTED TO DEVELOP ALONG AND NEAR THE CASCADES THIS AFTERNOON. THIS SHOULD GIVE RISE TO BUILD-UPS ALONG AND NEAR THE TRINITY ALPS AND CASCADE CREST THIS AFTERNOON, SHIFTING EASTWARD TO THE LEE OF THE CASCADES TOWARDS THE EVENING. CONDITIONS ARE MOST FAVORABLE FOR SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN THESE LEE AND EAST SIDE AREAS. MOST GUIDANCE FOCUSES ACTIVITY THIS EVENING IN THE WARNER MOUNTAINS OF LAKE COUNTY AND ANOTHER IN NORTHERN LAKE COUNTY THIS EVENING. WHILE FIRE DANGER DID REACH HIGH IN PORTIONS OF THE MODOC ON MONDAY, FORECAST FIRE DANGER FOR TODAY IS MODERATE. ADDITIONALLY, DEPARTURE FROM AVERAGE GREENNESS IS SPOTTY IN TERMS OF DEFICITS, SO SUSPECT THERE`S SOME GREEN-UP COMPONENT TO THE LIVE FUELS NOW. MODELS INDICATE THAT ANY STORMS THAT DO GET GOING WILL PRODUCE GUSTY OUTFLOW WINDS MAINLY IN THE 20 TO 30 MPH RANGE, BUT ALSO SOME MEASURABLE RAINFALL. THUS, DESPITE UNUSUALLY DRY CONDITIONS DUE TO THE ONGOING DROUGHT, WE HAVE DECIDED THAT THIS EVENT DOES NOT WARRANT ANY WARNINGS. INSTEAD, A HEADS-UP TYPE OF HEADLINE WILL BE MAINTAINED IN THE FORECAST. BTL/PETRUCELLI && .MFR WATCHES/WARNINGS/ADVISORIES... OR...NONE. CA...NONE. PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 AM PDT THURSDAY FOR PZZ350-356-370-376. HAZARDOUS SEAS WARNING UNTIL 5 AM PDT THURSDAY FOR PZZ356-376. GALE WARNING UNTIL 5 AM PDT THURSDAY FOR PZZ356-376. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 AM PDT THURSDAY FOR PZZ350-356-370-376. $$ MND/MAP/MAS
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
344 PM CDT TUE APR 21 2015 .SHORT TERM... SURFACE DEWPOINTS HAVE BEEN FAIRLY STAGNANT ACROSS THE FORECAST AREA TODAY AS MODEST ADVECTION BALANCES MIXING. AT 3 PM...SATELLITE IMAGERY SHOWED A DEVELOPING CUMULUS FIELD IN EASTERN NEW MEXICO WHERE THE DEWPOINTS ARE MOSTLY IN THE 30S. MORE EXTENSIVE DEVELOPMENT WAS ONGOING ACROSS THE SACRAMENTOS AND SANGRES OF NM. THE HRRR HAS BEEN FAIRLY CONSISTENT WITH BRINGING SOME OF THIS ACTIVITY EASTWARD ACROSS THE WESTERN AND CENTRAL SOUTH PLAINS LATE THIS AFTERNOON AND EVENING...ALTHOUGH IT IS ABOUT THE ONLY MODEL TO DO SO. FCST SOUNDINGS IN THESE AREAS INDICATE ANY STORMS THAT DO DEVELOP WILL BE HIGH-BASED HAVE LITTLE CAPE TO WORK WITH...SO THEY WILL ONLY BE CAPABLE OF SPOTTY RAIN AND STRONG WIND GUSTS. IF ANY STORMS CAN SURVIVE FARTHER TO THE EAST THIS EVENING AND ENCOUNTER THE DEEPER MOISTURE...IT IS NOT OUT OF THE QUESTION THAT A HAIL THREAT COULD DEVELOP...BUT THIS APPEARS UNLIKELY AT THIS TIME. TONIGHT...THE LOW LEVEL JET WILL BRING RICHER MOISTURE NWWD INTO WEST TEXAS...WITH THE SURFACE DRYLINE RETREATING THROUGH MOST IF NOT ALL OF THE CWA...PERHAPS HOLDING BACK ACROSS THE FAR SW TX PANHANDLE. NAM FCST SNDGS SHOW FOG POTENTIAL ACROSS THE SOUTHERN AND CENTRAL SOUTH PLAINS BY EARLY WED MORNING SO WE HAVE ADDED A PATCHY MENTION IN THE GRIDS....SOME AREAS OF LOW STRATUS ARE POSSIBLE AS WELL. MEANWHILE TO OUR NORTH ACROSS THE PANHANDLES...THEY WILL LIKELY SEE SOME OVERNIGHT TSTM ACTIVITY COINCIDING WITH A SWD-MOVING COLD FRONT. IT IS UNCERTAIN WHAT IMPACT STORM COLD POOLS MAY HAVE ON THE PROGRESS OF THE FRONT...WHICH TENDS TO LOWER OUR CONFIDENCE ON HOW THE FRONT/OUTFLOW BOUNDARY WILL BEHAVE ON WEDNESDAY. IN GENERAL...WE EXPECT THE BOUNDARY TO SINK SOUTH THROUGH THE FAR SRN PANHANDLE AND POSSIBLY INTO THE NORTHERN ROLLING PLAINS. BACK TO THE WEST...THE DRYLINE SHOULD FORM UP AND MOVE EAST AS A SURFACE TROUGH DEVELOPS FROM EASTERN NM INTO THE ROLLING PLAINS. ALTHOUGH WE HAVE TO STRESS A LARGE UNCERTAINTY IN THE PARTICULARS...A TRIPLE-POINT MAY DEVELOP SOMEWHERE FROM OUR CENTRAL TO SOUTHEAST COUNTIES. BACKED FLOW AND HIGH SURFACE MOISTURE WILL BE POSSIBLE ACROSS AT LEAST OUR NE ZONES. WITH A MID-LVL SHORTWAVE PASSING ACROSS THE AREA DURING THE DAY...STRONG INSTABILITY AND DEEP SHEAR IS LIKELY TO DEVELOP ALONG AND TO THE NORTH AND EAST OF THE TRIPLE-POINT. GUIDANCE GENERALLY SHOWS A STRONG CONVECTIVE SIGNAL IN THIS AREA BY LATE AFTERNOON...ALTHOUGH WITH A LOT OF SPREAD RECORDING THE AREA POTENTIALLY IMPACTED. WHERE STORMS OCCUR...SEVERE WEATHER WILL BE A STRONG POSSIBILITY...INCLUDING THE POSSIBILITY OF TORNADOES DEPENDING THE ORIENTATION/EVOLUTION ON THE BOUNDARY/S/. FARTHER WEST...WE HAVE TRIMMED POPS DOWN OUR NEAR THE STATE LINE BUT LEFT A SLIGHT CHANCE GOING ACROSS MUCH OF THE SOUTH PLAINS IN CASE THE DRYLINE IS FARTHER WEST THAN ANTICIPATED. .LONG TERM... THE PATTERN THEME THROUGH EARLY NEXT WEEK REMAINS THAT OF A PROGRESSIVE ONE AS A SERIES OF SOUTHERN STREAM TROUGHS IMPACT THE REGION. ONLY UNTIL THEREAFTER DOES THE PATTERN SHOW SIGNS OF TRENDING MORE STAGNANT IN THE FORM OF MID-CONUS LONGWAVE RIDGING. ALL DAYS CONSIDERED...WEDNESDAY EVENING LOOKS TO GRAB THE LIMELIGHT FOR SENSIBLE WEATHER AS A SEVERE CONVECTIVE EPISODE SHOULD BE WELL UNDERWAY. LOCATION OF THIS EVENT WILL BE HIGHLY DEPENDENT ON A STATIONARY FRONT CURRENTLY PROGGED TO BISECT OUR CWA FROM NW-SE BY LATE EVENING...THOUGH MODELS CONTINUE TO FAVOR OUR NERN COUNTIES. BACKGROUND FORCING APPEARS RATHER SUBDUED AND LINKED MOSTLY TO A SHORTWAVE TROUGH CRESTING SHALLOW RIDGING ALOFT AND A NORTHWARD PUSH OF STRONGER SUBTROPICAL WINDS. THIS ALONG WITH FAVORABLE DEEP SHEAR MAY SERVE TO KEEP CONVECTIVE MODES RESTRICTED TO ISOLATED OR SCATTERED SUPERCELLS. FEEL 40-50 PERCENT POPS WED EVENING ARE REPRESENTATIVE OF THIS SCENARIO FOR NOW BEFORE PRECIP EVENTUALLY MOVES DOWNSTREAM LATE WED NIGHT. BEYOND WEDNESDAY NIGHT...THE WAVERING FRONTAL BOUNDARY SHOULD LIFT NORTH AS A WARM FRONT IN ADVANCE OF A MORE ROBUST TROUGH LIFTING OUT OF THE DESERT SOUTHWEST. THIS WAVE WILL PROJECT EVEN STRONGER WINDS ATOP THE REGION PERHAPS ACCOMPANIED BY OCCASIONAL IMPULSES AND SLIGHT CHANCE POPS...ESPECIALLY OFF THE CAPROCK WHERE LL MOISTURE WILL HAVE A GREATER RESIDENCE TIME. MODEL CONSENSUS IS FOR DRY SLOTTING TO SURGE ATOP THE CAPROCK COUNTIES BY EARLY FRIDAY AND QUICKLY SWEEP EAST AS THE BASE OF THE TROUGH LIFTS TO OUR NORTH. THE TIMING AND PATH OF THIS TROUGH SUGGEST A WINDY DAY IS IN STORE YET WE REMAIN A BIT RELUCTANT TO BITE ON THE STRONG WINDS AS PROGGED BY THE GFS AT TIMES. TIME-HEIGHT X-SECTIONS SHOW NEXT TO NIL CIRRUS...SO WE MAY NEED TO RATCHET UP OUR 20-30 MPH WINDS EVEN FURTHER IN LATER FORECASTS IF THIS THEME PERSISTS. BY SATURDAY...QUIETER WEATHER UNDER TRANSIENT RIDGING WILL BE REPLACED BY ONE FINAL TROUGH AT SOME POINT ON SUNDAY AHEAD OF MODIFIED CANADIAN AIR WHICH LOOKS TO DIVE INTO THE GULF COME MONDAY. PRECIP MERIT FROM SUN-SUN NIGHT DOESN/T SHOW MUCH SUBSTANCE AMONG THE LATEST GLOBAL MODELS...SO POPS WERE SCALED BACK IN COVERAGE TO BETTER MATCH THE DRIER SUPERBLEND AND CONSENSUS ROUTES. && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 33/93
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
114 PM CDT TUE APR 21 2015 .AVIATION... /18Z TAFS/ MVFR CIGS BETWEEN DRT AND SAT/SSF/AUS SHOULD CONTINUE TO LIFT AND STAY CLEAR OF OUR TAF SITES THIS AFTERNOON. SOUTHEAST FLOW FROM THE GULF HAS RETURNED...WHICH COMBINED WITH WEAK LIFT WILL LEAD TO CIGS LOWERING TO MVFR AROUND 3-4Z AND IFR AROUND 8Z AT ALL TAF SITES. MODEL GUIDANCE SUGGESTS LIFR CIGS WITH TEMPO VLIFR CIGS ARE POSSIBLE TONIGHT AT SAT/SSF/DRT...BUT HELD OFF PREVAILING THAT FOR NOW. ISOLATED -SHRA IS POSSIBLE TONIGHT WITH A STRENGTHENING LLJ AND -TSRA IS POSSIBLE TOMORROW AFTERNOON...BUT CAPPING ALOFT WILL LIKELY KEEP COVERAGE TOO ISOLATED TO MENTION IN TAFS. LH && .PREV DISCUSSION... /ISSUED 1201 PM CDT TUE APR 21 2015/ UPDATE... INCREASING CLOUD COVER HAS KEPT TEMPERATURES DOWN SLIGHTLY FROM FORECAST. THIS TREND WILL CONTINUE AS SOUTHERLY LOWER LEVEL FLOW INCREASES MOISTURE. HAVE LOWERED HIGH TEMPERATURES A COUPLE OF DEGREES IN MANY AREAS FOR THIS AFTERNOON. ALSO...DUE TO UPPER LEVEL RIDGE BUILDING IN FROM THE SOUTH WILL SERVE TO INCREASE CONVECTIVE INHIBITION. AS A RESULT...WILL REMOVE MENTION OF THUNDER. HOWEVER...WILL MAINTAIN SHOWERS AS RADAR IS SHOWING A BAND OF SHOWERS STREAMING INTO TOWARD OUR AREA FROM THE SOUTH. PREV DISCUSSION... /ISSUED 652 AM CDT TUE APR 21 2015/ AVIATION... /12Z TAFS/ CLEAR SKIES ARE IN PLACE AS UPPER LEVEL MOISTURE PUSHES TO THE EAST AND LIGHT WINDS FROM THE NORTHWEST AND NORTHEAST DOMINATE AT THE SURFACE. HOWEVER...THIS CONDITION IS FORECAST TO QUICKLY CHANGE THIS MORNING AS SOUTHERLY WINDS RETURN. MVFR CONDITIONS ARE EXPECTED ACROSS KSAT AND KSSF AROUND 14Z TO 16Z AS A POCKET OF LOW CLOUDS FORM ACROSS THE SAN ANTONIO METRO AREA. CLOUDS WILL INCREASE THROUGHOUT THE DAY AS GULF MOISTURE PUSHES NORTHWARD FOR THE RETURN OF MVFR CONDITIONS ACROSS AREA SITES THIS EVENING. AREA SOUNDINGS AND MOS GUIDANCE ARE SUGGESTING CIGS TO LOWER TO IFR/LIFR OVERNIGHT AS SATURATED AIR DOMINATES THE AREA. WINDS WILL BE FROM THE SOUTHEAST FOR THE MOST PARTS WITH SPEEDS OF 10 KNOTS AND GUSTING UP TO 21 KNOTS ACROSS KDRT THIS AFTERNOON. PREV DISCUSSION... /ISSUED 442 AM CDT TUE APR 21 2015/ SHORT TERM (TODAY THROUGH WEDNESDAY)... A WEAK UPPER LEVEL DISTURBANCE MOVED OVER THE AREA OVERNIGHT AND CLEARING SKIES ARE LEFT IN ITS WAKE. THE CLEARING SHOULD BE TEMPORARY AS A MOIST LAYER AT 850 HPA SHOULD SATURATE IN MANY AREAS. THE CLOUDS WILL PROBABLY BE SCT VARIABLE TO BKN SINCE THE MOISTURE LAYER APPEARS THIN. THUS WILL GO WITH SLIGHTLY ABOVE BLENDED GUIDANCE HIGHS TODAY. RAP SOUNDINGS SUGGEST A BREAKABLE CAP SHOULD THERE BE ENOUGH MOISTURE SO WILL CONTINUE WITH ISOLATED POPS. AN UPPER LOW CURRENTLY OVER SOUTHERN CA WILL CONTINUE TO CARVE DEEPER OVER THE BAJA PENINSULA THROUGH WEDNESDAY. DEEPENING MOISTURE WILL LEAD TO INCREASED RAIN CHANCES AND A FEW STRONG STORMS AND POSSIBLE SUPERCELLS AS NOTED IN THE SPC DAY 2 OUTLOOK. LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)... A FAIRLY LIGHT LOW LEVEL FLOW WEDNESDAY NIGHT INTO THURSDAY MEANS THAT THERE COULD BE SOME REMNANT OUTFLOW BOUNDARIES LEFT FROM WEDNESDAY STORMS TO BRING ADDITIONAL STORM FOCUS FOR THURSDAY AS THE UPPER LOW BEGINS TO LIFT INTO THE SOUTHERN ROCKIES. HIGHEST POPS OF THE WEEK ARE THUS SAVED FOR THURSDAY NIGHT INTO FRIDAY. THE EJECTION OF THE LOW INTO A SHALLOW TROUGH LEAVES SOME COVERAGE UNCERTAINTIES THIS FAR SOUTH...SO DO NOT WANT TO OVER-ADVERTISE THE SEVERE THREAT BEYOND A NOD IN THE HWO. POPS SHOULD LOWER SATURDAY INTO SUNDAY AS FLAT RIDGING ALOFT RETURNS. MOISTURE IS SUFFICIENT FOR STORMS...BUT EXPECT A STRONGER CAPPING INVERSION. ANOTHER LOW LATITUDE UPPER DISTURBANCE IS FORECAST BY THE GFS TO BRING RAIN AND STORMS BY MIDWEEK...BUT WILL KEEP WITH THE MORE CONSERVATIVE ECMWF UNTIL THE PATTERN DIFFERENCES BETWEEN MODELS DECREASE. TEMPERATURES THROUGH THE PERIOD SHOULD CONTINUE TO BE SEASONAL. A WEAK FRONT EXPECTED SATURDAY WILL PROBABLY ADD TO DAYTIME TEMPERATURES THROUGH REDUCED CLOUDINESS. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 80 66 82 69 86 / 10 20 40 20 20 AUSTIN BERGSTROM INTL AIRPORT 79 66 81 68 85 / 10 20 40 30 20 NEW BRAUNFELS MUNI AIRPORT 79 66 82 69 87 / 10 20 40 20 20 BURNET MUNI AIRPORT 77 66 81 68 85 / 10 20 30 20 20 DEL RIO INTL AIRPORT 81 67 86 70 88 / 10 30 20 10 20 GEORGETOWN MUNI AIRPORT 79 67 82 68 86 / 10 20 40 30 20 HONDO MUNI AIRPORT 80 67 82 69 87 / 10 30 30 10 20 SAN MARCOS MUNI AIRPORT 78 66 81 68 85 / 10 20 40 20 20 LA GRANGE - FAYETTE REGIONAL 79 66 82 70 85 / 10 20 40 30 20 SAN ANTONIO INTL AIRPORT 79 68 82 71 86 / 10 20 30 20 20 STINSON MUNI AIRPORT 81 68 82 71 87 / 10 20 30 10 20 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...01 SYNOPTIC/GRIDS...04 PUBLIC SERVICE/DATA COLLECTION...12
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1201 PM CDT TUE APR 21 2015 .UPDATE... INCREASING CLOUD COVER HAS KEPT TEMPERATURES DOWN SLIGHTLY FROM FORECAST. THIS TREND WILL CONTINUE AS SOUTHERLY LOWER LEVEL FLOW INCREASES MOISTURE. HAVE LOWERED HIGH TEMPERATURES A COUPLE OF DEGREES IN MANY AREAS FOR THIS AFTERNOON. ALSO...DUE TO UPPER LEVEL RIDGE BUILDING IN FROM THE SOUTH WILL SERVE TO INCREASE CONVECTIVE INHIBITION. AS A RESULT...WILL REMOVE MENTION OF THUNDER. HOWEVER...WILL MAINTAIN SHOWERS AS RADAR IS SHOWING A BAND OF SHOWERS STREAMING INTO TOWARD OUR AREA FROM THE SOUTH. && .PREV DISCUSSION... /ISSUED 652 AM CDT TUE APR 21 2015/ AVIATION... /12Z TAFS/ CLEAR SKIES ARE IN PLACE AS UPPER LEVEL MOISTURE PUSHES TO THE EAST AND LIGHT WINDS FROM THE NORTHWEST AND NORTHEAST DOMINATE AT THE SURFACE. HOWEVER...THIS CONDITION IS FORECAST TO QUICKLY CHANGE THIS MORNING AS SOUTHERLY WINDS RETURN. MVFR CONDITIONS ARE EXPECTED ACROSS KSAT AND KSSF AROUND 14Z TO 16Z AS A POCKET OF LOW CLOUDS FORM ACROSS THE SAN ANTONIO METRO AREA. CLOUDS WILL INCREASE THROUGHOUT THE DAY AS GULF MOISTURE PUSHES NORTHWARD FOR THE RETURN OF MVFR CONDITIONS ACROSS AREA SITES THIS EVENING. AREA SOUNDINGS AND MOS GUIDANCE ARE SUGGESTING CIGS TO LOWER TO IFR/LIFR OVERNIGHT AS SATURATED AIR DOMINATES THE AREA. WINDS WILL BE FROM THE SOUTHEAST FOR THE MOST PARTS WITH SPEEDS OF 10 KNOTS AND GUSTING UP TO 21 KNOTS ACROSS KDRT THIS AFTERNOON. PREV DISCUSSION... /ISSUED 442 AM CDT TUE APR 21 2015/ SHORT TERM (TODAY THROUGH WEDNESDAY)... A WEAK UPPER LEVEL DISTURBANCE MOVED OVER THE AREA OVERNIGHT AND CLEARING SKIES ARE LEFT IN ITS WAKE. THE CLEARING SHOULD BE TEMPORARY AS A MOIST LAYER AT 850 HPA SHOULD SATURATE IN MANY AREAS. THE CLOUDS WILL PROBABLY BE SCT VARIABLE TO BKN SINCE THE MOISTURE LAYER APPEARS THIN. THUS WILL GO WITH SLIGHTLY ABOVE BLENDED GUIDANCE HIGHS TODAY. RAP SOUNDINGS SUGGEST A BREAKABLE CAP SHOULD THERE BE ENOUGH MOISTURE SO WILL CONTINUE WITH ISOLATED POPS. AN UPPER LOW CURRENTLY OVER SOUTHERN CA WILL CONTINUE TO CARVE DEEPER OVER THE BAJA PENINSULA THROUGH WEDNESDAY. DEEPENING MOISTURE WILL LEAD TO INCREASED RAIN CHANCES AND A FEW STRONG STORMS AND POSSIBLE SUPERCELLS AS NOTED IN THE SPC DAY 2 OUTLOOK. LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)... A FAIRLY LIGHT LOW LEVEL FLOW WEDNESDAY NIGHT INTO THURSDAY MEANS THAT THERE COULD BE SOME REMNANT OUTFLOW BOUNDARIES LEFT FROM WEDNESDAY STORMS TO BRING ADDITIONAL STORM FOCUS FOR THURSDAY AS THE UPPER LOW BEGINS TO LIFT INTO THE SOUTHERN ROCKIES. HIGHEST POPS OF THE WEEK ARE THUS SAVED FOR THURSDAY NIGHT INTO FRIDAY. THE EJECTION OF THE LOW INTO A SHALLOW TROUGH LEAVES SOME COVERAGE UNCERTAINTIES THIS FAR SOUTH...SO DO NOT WANT TO OVER-ADVERTISE THE SEVERE THREAT BEYOND A NOD IN THE HWO. POPS SHOULD LOWER SATURDAY INTO SUNDAY AS FLAT RIDGING ALOFT RETURNS. MOISTURE IS SUFFICIENT FOR STORMS...BUT EXPECT A STRONGER CAPPING INVERSION. ANOTHER LOW LATITUDE UPPER DISTURBANCE IS FORECAST BY THE GFS TO BRING RAIN AND STORMS BY MIDWEEK...BUT WILL KEEP WITH THE MORE CONSERVATIVE ECMWF UNTIL THE PATTERN DIFFERENCES BETWEEN MODELS DECREASE. TEMPERATURES THROUGH THE PERIOD SHOULD CONTINUE TO BE SEASONAL. A WEAK FRONT EXPECTED SATURDAY WILL PROBABLY ADD TO DAYTIME TEMPERATURES THROUGH REDUCED CLOUDINESS. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 80 66 82 69 86 / 10 10 30 30 20 AUSTIN BERGSTROM INTL AIRPORT 79 66 81 68 85 / 10 10 30 30 20 NEW BRAUNFELS MUNI AIRPORT 79 66 82 69 87 / 10 20 30 30 20 BURNET MUNI AIRPORT 77 66 81 68 85 / 10 20 30 30 20 DEL RIO INTL AIRPORT 81 67 86 70 88 / 10 20 20 10 20 GEORGETOWN MUNI AIRPORT 79 67 82 68 86 / 10 10 30 30 20 HONDO MUNI AIRPORT 80 67 82 69 87 / 10 20 30 20 20 SAN MARCOS MUNI AIRPORT 78 66 81 68 85 / 10 20 30 30 20 LA GRANGE - FAYETTE REGIONAL 79 66 82 70 85 / 10 10 30 30 20 SAN ANTONIO INTL AIRPORT 79 68 82 71 86 / 10 20 30 20 20 STINSON MUNI AIRPORT 81 68 82 71 87 / 10 20 30 20 20 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...01 SYNOPTIC/GRIDS...04 PUBLIC SERVICE/DATA COLLECTION...12
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
326 PM CDT TUE APR 21 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 326 PM CDT TUE APR 21 2015 CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED RIDGING OVER THE WESTERN U.S. INTO ALBERTA AND VERY DEEP TROUGHING OVER THE FORECAST AREA INTO THE GREAT LAKES. WITHIN THIS TROUGH WAS AN UPPER LOW OVER EASTERN LAKE SUPERIOR...A SHORTWAVE DROPPING SOUTH TOWARDS I-90 IN THE FORECAST AREA...AND ANOTHER SHORTWAVE OVER NORTHEAST MN. COOL TEMPERATURES ALOFT REFLECTED BY 500MB TEMPS OF -27 TO -33C PER 12Z RAOBS...DAYTIME HEATING...NEAR SATURATED CONDITIONS BETWEEN 700-850MB AND THE AFOREMENTIONED SHORTWAVES HELPING TO PRODUCE PLENTY OF SHOWERS ACROSS THE REGION....ESPECIALLY ALONG AND NORTH OF I-94. TEMPERATURES HAVE STRUGGLED TO RISE WITH CLOUDS...PRECIP AND 850MB TEMPS OF -3 TO -7C. READINGS HAVE ONLY CLIMBED INTO THE MID 30S TO LOW 40S. THE COLD TEMPERATURES HAVE SUPPORTED A MIX OF RAIN AND SNOW...WITH THE SNOW CONFINED MORESO TO HIGHER ELEVATIONS AND TAYLOR/CLARK COUNTIES. ON TOP OF THE COOL AIR...A TIGHT PRESSURE GRADIENT AND 925MB WINDS OF 25-35 KT HAS RESULTED IN WINDS GUSTING TO THE 925MB SPEEDS...MAKING IT FEEL FALL-LIKE. THESE WINDS ARE JUST BELOW ADVISORY CRITERIA. THE OVERALL UPPER PATTERN CHANGES LITTLE IN THE NEXT 24 HOURS WITH ONLY A SLIGHT DRIFT EASTWARD OF THE UPPER LOW AND TROUGHING. THIS SLIGHT DRIFT LOOKS TO BE ENOUGH SUCH THAT MUCH OF THE SHORTWAVE AND INSTABILITY INDUCED SHOWERS ON WEDNESDAY WILL FALL EAST OF THE FORECAST AREA. HOWEVER...PORTIONS OF TAYLOR AND ADAMS COULD GET CLIPPED IN THE AFTERNOON. GETTING BACK TO TONIGHT...GENERAL MODEL CONSENSUS SUGGESTS THE LOSS OF DAYTIME HEATING WILL ALLOW SHOWER ACTIVITY TO BECOME MORE ISOLATED THROUGH THE EVENING...EVENTUALLY ENDING BY MIDNIGHT. CLOUDS LOOK TO HOLD OVER MUCH OF THE FORECAST AREA TONIGHT...AIDED BY A SURGE OF 850MB MOISTURE CURRENTLY IN NORTHWEST ONTARIO DROPPING SOUTHWARD WITH THE SHORTWAVE IN NORTHEAST MN. SUBSIDENCE IN THE WAKE OF THIS SHORTWAVE...COMBINED WITH 925-700MB WINDS BACKING A BIT MORE WESTERLY ON WEDNESDAY...WILL HELP TO RESULT IN MORE SUNSHINE. DESPITE THE CLOUDS TONIGHT...AND A PERSISTENT BREEZE...TEMPERATURES WILL STILL FALL AS THAT SHORTWAVE IN NORTHEAST MN DRAGS COLDER AIR INTO THE FORECAST AREA. BY 12Z WED...850MB TEMPS ARE PROGGED TO DROP TO -8 TO -11C...OR ALMOST 2 STANDARD DEVIATIONS BELOW NORMAL. GUIDANCE LOWS IN THE MID 20S TO LOW 30S SEEM REASONABLE. HAVING MORE SUNSHINE ON WEDNESDAY WILL HELP PRODUCE A WARMER DAY THAN TODAY...ALBEIT STILL WELL BELOW NORMAL GIVEN 850MB TEMPS ONLY CLIMBING TO -2 TO -7C BY 00Z THU. MOST LOCATIONS SHOULD CLIMB INTO THE 40S...WITH LOW 50S LIKELY IN RIVER VALLEYS AND THE SOUTHWEST PORTION OF THE FORECAST AREA. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 326 PM CDT TUE APR 21 2015 THE UPPER FLOW PATTERN LOOKS TO BECOME MORE PROGRESSIVE THROUGH THE END OF THE WEEK IN RESPONSE TO A DEEP UPPER TROUGH APPROACHING THE PACIFIC NORTHWEST. THIS WILL HELP TO PUSH THE UPPER RIDGING AND WARMER AIR OVER THE WESTERN U.S. TOWARDS THE FORECAST AREA. 850MB TEMPS DO NOT CHANGE A WHOLE LOT WED NIGHT...BUT MORE IMPRESSIVE WARM ADVECTION COMES IN FOR THU WITH 850MB TEMPS REACHING 0 TO -2C BY 00Z FRI...AND 0 TO 4C BY 00Z SAT. LOW PRECIPITABLE WATER ON THURSDAY...AROUND 0.1 INCHES...SHOULD HELP TO TANK DEWPOINTS AND RESULTING RHS. COMBINED WITH A DRYING DAY ON WEDNESDAY AND A 10-15 MPH NORTHWEST BREEZE...FIRE WEATHER COULD BE A CONCERN. SEE FIRE WEATHER SECTION BELOW. FOR FRIDAY INTO SATURDAY...AN UPPER LOW CURRENTLY NEAR LOS ANGELES IS PROGGED TO LIFT THROUGH THE CENTRAL PLAINS AND TRACK EASTWARD ACROSS ILLINOIS. ALTHOUGH THIS TRACK IS SOUTH OF THE FORECAST AREA...MOISTURE ADVECTION SPREADS NORTHWARD AHEAD OF THE UPPER LOW TO HELP PRODUCE SOME RAIN. THE SPEED HAS SLOWED DOWN A BIT...AND AS A RESULT DELAYED THE SPREADING OF CHANCES OF RAINFALL EASTWARD ON FRIDAY. FURTHER DELAYS MAY BE NEEDED. RAIN CHANCES SPREAD ACROSS THE FORECAST AREA FRIDAY NIGHT AND THEN SHIFT TO SOUTH OF I-90 ON SATURDAY...RESULTING FROM EASTERLY FLOW DRAGGING MORE DRY AIR INTO NORTHERN SECTIONS. OVERALL APPEARS TO BE A LIGHT RAIN...WITH THE HEAVIER RAIN TO THE SOUTH TIED TO THE UPPER LOW FORCING. DRIER WEATHER LOOKS TO FOLLOW SATURDAY NIGHT AND SUNDAY AS UPPER RIDGING BUILDS BACK INTO THE FORECAST AREA FROM THE WEST. TEMPERATURES SHOULD REBOUND CLOSER TO NORMAL AS WELL WITH MORE SUN ON SUNDAY AND 850MB TEMPS IN THE 0-4C RANGE. FOR EARLY NEXT WEEK UNCERTAINTY BEGINS TO INCREASE. NOT SO MUCH ON THE UPPER PATTERN WHERE MODELS ADVERTISE TROUGHING DEVELOPING FROM THE NORTHEAST U.S. INTO THE SOUTHEAST U.S....BUT WITH PRECIPITATION CHANCES AS THIS TROUGH DEVELOPS. THE 21.12Z GFS HAS A SHORTWAVE TROUGH DROPPING THROUGH THE REGION TO BRING PRECIPITATION TO THE AREA. MEANWHILE THE 21.12Z ECMWF AND CANADIAN SUGGEST A DRY PERIOD AS HIGH PRESSURE DOMINATES AT THE SURFACE...WITH THE AFOREMENTIONED SHORTWAVE TROUGH FALLING APART. FOR NOW HAVE WENT WITH THE CONSENSUS AND HAVE 20-30 PERCENT CHANCES. HOW THIS SHORTWAVE TROUGH EVOLVES ALSO HAS AN IMPACT ON TEMPERATURES. IN THE CASE OF THE 21.12Z GFS...IT SUGGESTS 850MB TEMPS PLUNGE TO AROUND -4C BY 12Z TUE...ABOUT 8C COLDER THAN THE ECMWF. ALSO FOLLOWED CONSENSUS HERE FOR NOW WITH TEMPS JUST SHY OF NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1201 PM CDT TUE APR 21 2015 EXPECT WINDY CONDITIONS OUT OF THE NORTHWEST TO CONTINUE THROUGH THE TAF PERIOD WITH GUSTS OF 25 TO 35 KT THIS AFTERNOON. VFR SHOULD PERSIST WITH A BRIEF MVFR CEILING POSSIBLE WITH A HEAVIER SHOWER THIS AFTERNOON. SOME GUIDANCE HINTS AT MVFR CEILINGS EARLY WEDNESDAY MORNING AS BACK EDGE OF CLOUDS MOVE THROUGH. HOWEVER...WITH MIX OF VFR AND MVFR UPSTREAM ACROSS MINNESOTA KEPT CEILINGS AT VFR WITH SCATTERING OUT BY MID WEDNESDAY MORNING. && .FIRE WEATHER... ISSUED AT 326 PM CDT TUE APR 21 2015 AFTER SOME RECENT COOL/WET DAYS...CONDITIONS LOOK TO DRY OUT AGAIN WEDNESDAY AND THURSDAY. RELATIVE HUMIDITIES ARE EXPECTED TO DROP INTO THE 20S ON WEDNESDAY AND MAY EVEN DROP BELOW 20 PERCENT IN A FEW SOUTHEAST MN LOCATIONS ON THURSDAY. FIGURE MUCH OF WEDNESDAY WILL BE A DRYING DAY FOR FUELS GIVEN THE WET WEATHER...WITH A 15 TO 25 MPH NORTHWEST BREEZE AIDING IN THE DRYING. THEREFORE THURSDAY WOULD APPEAR TO BE THE MORE CONCERNING DAY...THOUGH WINDS LOOK LIGHTER IN THE 10 TO 15 MPH RANGE. NEVERTHELESS...WELL HAVE TO KEEP A CLOSE EYE ON THURSDAY AND SEE TOO WHERE ALL THE VEGETATION STANDS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...WIND ADVISORY UNTIL 6 PM CDT THIS EVENING FOR MNZ086-087-094-095. IA...WIND ADVISORY UNTIL 6 PM CDT THIS EVENING FOR IAZ008>010-018-019- 029-030. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...CC FIRE WEATHER...AJ