Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/18/15


AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
951 PM MDT FRI APR 17 2015 .UPDATE... ISSUED AT 942 PM MDT FRI APR 17 2015 ALTHOUGH ADDITIONAL SHOWERS WILL BE MOVING INTO THE URBAN CORRIDOR FROM DENVER SOUTHWARD AT THIS TIME...AND THEN INTO FRONT RANGE FOOTHILLS OVERNIGHT...THE COVERAGE DOES NOT APPEAR TO BE SUFFICIENT ENOUGH TO CONTINUE WITH THE WINTER STORM WARNING...THEREFORE IT HAS BEEN CANCELLED. THE WRAP AROUND SNOWFALL IS EXPECTED TO MOVE INTO THE MOUNTAINS BUT MOST OF THIS WILL OCCUR ON SATURDAY. HAVE ALSO CANCELLED TORNADO WATCH 69 FOR OUR NORTHEAST PLAINS. IF SOME CLEARING DOES OCCUR OVERNIGHT THEN FOG MAY AGAIN RETURN FROM AROUND DENVER EASTWARD...WILL KEEP PATCHY COVERAGE ALONG THE URBAN CORRIDOR...WITH A BIT MORE COVERAGE FURTHER EAST. UPDATE ISSUED AT 613 PM MDT FRI APR 17 2015 LATEST HRRR IS MOVING THE PCPN OVER SERN CO INTO THE PALMER DIVIDE SHORTLY THEN NORTHWEST INTO THE URBAN CORRIDOR. HAVE INCREASED THE POPS THIS EVENING. PCPN WILL BE RAIN OR A RAIN/SNOW MIX. DUE TO THE CONVECTIVE NATURE OF THIS SYSTEM...AREAS OVER THE PALMER DIVIDE AND THE CHEYENNE RIDGE COULD PICK UP AN INCH OR TWO OF SNOW. ANY SNOWFALL THAT DEVELOPS ELSEWHERE ALONG THE URBAN CORRIDOR SHOULD BE AN INCH OR LESS. TORNADO WATCH REMAINS IN EFFECT FOR MORGAN....WASHINGTON...LOGAN...SEDGWICK AND PHILLIPS COUNTIES UNTIL MIDNIGHT. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 124 PM MDT FRI APR 17 2015 UPPER LEVEL LOW CENTERED OVER SOUTH CENTRAL COLORADO WILL SLOWLY SPIN NORTHEAST ACROSS THE STATE AND END UP OVER THE NORTHEAST CORNER SATURDAY AFTERNOON. DRIER AIR HAS ROTATED NORTH ACROSS THE AREA THIS AFTERNOON AND BROUGHT THE WIDESPREAD RAIN AND SNOW TO AN END. CLEARING DUE TO THE DRIER AIR HAS ALLOWED SOME WARMING. HIRES MODELS SHOWING SCATTERED CONVECTION FILLING IN DURING THE LATE AFTERNOON AND EVENING. WILL KEEP SCATTERED TO LIKELY POPS IN THE FORECAST THIS EVENING FOR THIS. ALREADY CANCELED THE ADVISORY WHERE THE SNOW ENDED IN PARK COUNTY AND THE PALMER DIVIDE. MAY BE ABLE TO CANCEL THE WINTER STORM WARNING AS WELL. WILL HOLD OFF FOR NOW AND SEE HOW MUCH CONVECTION FORMS. OUTSIDE OF CONVECTION...ADDITIONAL SNOWFALL ONCE THE DRY AIR MOVES THROUGH SHOULD BE LIGHT. COOLED HIGH TEMPERATURES ARE FEW DEGREES FOR SATURDAY WITH COOL AIR OVER US FROM THE UPPER LEVEL LOW. NORTHWEST FLOW BEHIND THE LOW COMBINED WITH STEEP LAPSE WILL PRODUCE SNOW SHOWERS OVER THE MOUNTAINS. INCREASED POPS FOR THIS. NEW SNOWFALL FOR THE MOUNTAINS SATURDAY WILL GENERALLY BE LESS THAN 4 INCHES...THOUGH A FEW FAVORED OROGRAPHIC AREAS COULD SEE A LITTLE MORE. FOR THE FRONT RANGE...DOWNSLOPE FLOW WILL LIMIT PRECIPITATION CHANCES...THOUGH IT SHOULD BE UNSTABLE ENOUGH FOR SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. THE BEST CHANCE WILL BE OVER THE PLAINS CLOSER TO THE LOW AND AWAY FROM DOWNSLOPE. AIRMASS WILL BE WARM ENOUGH FOR RAIN SATURDAY WITH SNOW CONFINED TO THE FOOTHILLS AND MOUNTAINS. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 124 PM MDT FRI APR 17 2015 THE ACTIVE PATTERN CONTINUES THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. SATURDAY NIGHT INTO SUNDAY THE UPPER LEVEL LOW CENTER WILL MAKES ITS WAY EAST OVER THE CO AND KS BORDER. THIS WILL BRING INCREASED NORTHERLY FLOW OVER NE COLORADO WITH A TROUGH OVER THE WEST WILL HELP BRING A SURGE OF COOLER AIR THAT WILL SPREAD SNOW SHOWERS OVER THE MOUNTAINS AND FOOTHILLS. THE TROUGH WILL PUSH EAST HELPING TO DRY OUT THE PLAINS KEEPING THE REGION COOLER UNDER MOSTLY CLOUDY SKIES. TEMPERATURES FOR SUNDAY WILL CONTINUE TO BE BELOW SEASONAL NORMALS WITH HIGHS IN THE UPPER 40S TO LOWER 50S. SUNDAY NIGHT INTO MONDAY STRONG NW WILL PREVAIL WITH A NW ORIENTED JET MOVING INTO NE COLORADO. INCREASED MOISTURE IN THE MID LEVELS WITH A SURFACE TROUGH WILL HELP TO KEEP SNOW IN THE MOUNTAINS AND SCATTERED RAINSHOWERS OVER THE PLAINS THROUGH MONDAY NIGHT INTO TUESDAY MORNING. WILL KEEP A SLIGHT CHANCE WITH THIS SYSTEM WITH A CHANCE IN THE MOUNTAINS WITH DECENT ASCENT. TEMPERATURES FOR MONDAY AND TUESDAY WILL SLOWLY INCREASE TO SEASONAL NORMALS BY TUESDAY AFTERNOON AS THE UPPER LEVEL RIDING MOVES IN ALONG WITH SURFACE HIGH PRESSURE. DOWNSLOPING WINDS OFF THE FOOTHILLS WILL HELP TO WARM TEMPERATURES OVER THE PLAINS INTO WEDNESDAY WHERE MODELS HAVE HIGH TEMPERATURES REACHING INTO THE UPPER 60S AND LOWER 70S. UPPER LEVEL FLOW TURNS SOUTHWESTERLY AHEAD OF THE NEXT DISTURBANCE OVER SOUTHERN CA. THE MODELS DIVERGE AT THIS POINT WITH THE GFS BRINGING PRECIPITATION BACK INTO THE MOUNTAINS BY WEDNESDAY EVENING AND THE EC 24 HOURS BEHIND. WILL KEEP A SLIGHT CHANCE IN THE GRIDS OR THIS PERIOD BUT WILL CONTINUE TO MONITOR MODEL TRENDS. && .AVIATION...(FOR THE TAFS THROUGH 06Z SATURDAY EVENING) ISSUED AT 942 PM MDT FRI APR 17 2015 A MIX OF RAIN AND SNOW SHOWERS MOVING THROUGH DENVER AT THIS TIME...MVFR WITH THE POTENTIAL FOR IFR CIGS/VSBYS AT KAPA SHORTLY AND KBJC IN ANOTHER HOUR OR TWO. DURATION FOR THE IFR CONDITIONS SHOULD BE A LITTLE SHORTER AT KDEN. POTENTIAL FOR FOG DOES EXIST EARLY SATURDAY MORNING...12Z-15Z...SO WL KEEP THIS POSSIBILITY IN THE TAFS AS WELL. CONVECTION MAY BE PRODUCING VARIABLE WINDS FOR A TIME...BUT SHOULD SETTLE ON A LIGHT WNWLY WIND COMPONENT AFTER 06Z AND THIS SHOULD CONTINUE INTO SATURDAY. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...COOPER SHORT TERM...MEIER LONG TERM...BOWEN AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS PUEBLO CO
926 PM MDT FRI APR 17 2015 .UPDATE... ISSUED AT 919 PM MDT FRI APR 17 2015 UPDATED TO MODIFY POPS BASED ON 00Z GUIDANCE...FOCUSING HIGHEST CHANCES OVER THE PIKES PEAK REGION AND UPPER ARKANSAS AND CONTDVD NORTH OF GHWY 50. CUT BACK ON POPS TO THE SOUTH BUT WILL LEAVE ISOLD-SCT CHANCES OUT FOR THE HIGHER TERRAIN WITH THE UPPER LOW OVERHEAD. UPDATE ISSUED AT 844 PM MDT FRI APR 17 2015 MADE SOME ADJUSTMENTS TO THE WINTER HEADLINES BASED ON OBS...TRENDS AND LATEST MODEL GUIDANCE. LOOKS LIKE THE HEAVIEST AND MOST PERSISTENT PRECIP WILL BE OVER THE MTS NORTH OF HGWY 50 TONIGHT AND TOMORROW. SO...HAVE CANCELED THE ADVISORIES FOR THE SANGRES AND WETS. EXTENDED PIKES PEAK AND THE SAWATCH TIL 00Z SUN SINCE IT LOOKS LIKE PERIODS OF MODT SNOW WILL CONTINUE TOMORROW. TELLER MAY ALSO HAVE TO BE EXTENDED BUT GIVEN THE UNCERTAINTIES IN HOW THE BAND OF SNOW NORTH OF THE UPPER LOW WILL SET UP...WILL LEAVE THE ENDING TIME FOR SAT MORNING FOR NOW. HRRR HAS MOST OF THE HEAVIER QPF NORTH OF TELLER WHILE THE RAP AND NAM HAVE IT DIRECTLY OVER TELLER. SO...AMOUNTS ARE MOST UNCERTAIN OVER THE PIKES PEAK AREA BUT THE GOING ADVISORY COVERS THAT HAZARD FOR NOW. ROSE && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 256 PM MDT FRI APR 17 2015 CURRENTLY...THE UPPER LOW IS LOCATED OVER THE SW QUAD OF THE STATE THIS AFTERNOON...AND WAS WRAPPING DRY AIR UP INTO PORTIONS OF SOUTH CENTRAL AND SOUTHEAST CO EFFECTIVELY SHUTTING OFF PCPN AND EVEN CLOUD COVER FOR PORTIONS OF THE CWA. BEFORE THE DRY AIR MOVED IN...HEAVY SNOW WAS REPORTED OVER MANY OF THE AREA MTS AS WELL AS THE UPPER ARKANSAS RIVER BASIN...ALONG WITH SIGNIFICANT RAINFALL AMOUNTS ALL ALONG THE I25 CORRIDOR. CLOUD ENHANCEMENT WAS OCCURRING AS OF 3 PM OVER THE S MTS...SLOWLY SPREADING NORTH. FARTHER EAST...DRY AIR PUSHED INTO THE SE CORNER OF THE STATE AND HELPED TO PUSH THE SEVERE THREAT N AND NE. A FEW THUNDERSTORMS HAVE STRUGGLED ACROSS THE PLAINS THIS AFTN AS LOWER DEWPOINTS HAVE ROBBED LLVL ENERGY. TONIGHT AND TOMORROW...THE MAIN QUESTION IS WHERE WILL THE UPPER LOW GO. MODELS STILL INDICATE THAT IT WILL GRADUALLY MOVE NORTH INTO CENTRAL COLORADO THIS EVENING...THEN EDGE DUE EAST THROUGH TOMORROW AFTN. AFTER A BRIEF LULL...WHICH WILL MOST LIKELY HAVE CUSTOMERS SCRATCHING THEIR HEADS...ALL MODELS INCLUDING THE HI-RES OFFERINGS SHOW SHOWERS REDEVELOPING OVER THE PALMER DVD AND RAMPART RANGE...AS WELL AS THE CENTRAL MTS...N SANGRES AND WETS...THIS EVENING AND OVERNIGHT. ADDITIONAL SNOW AMOUNTS DO NOT LOOK AS SIGNIFICANT NOW AS THEY DID 12 HRS AGO...AND HANDLING OF THE HIGHLIGHTS WAS EXCEPTIONALLY TRICKY. DECIDED TO PUSH ALL ENDING TIMES OF HIGHLIGHTS TO 12Z TOMORROW MORNING...AND CONVERTED SOME OF THE ONGOING WARNINGS TO ADVISORIES. FURTHER ADJUSTMENTS TO THE POP AND HIGHLIGHT GRIDS WILL OCCUR UNDOUBTEDLY. AS FOR TEMPS...FRESH SNOW COVER FOR MUCH OF THE HIGHER TERRAIN AND HIGH VALLEYS WILL MAKE FOR A COLD NIGHT...AS WELL AS MODIFYING THE MAX TEMP TOMORROW DOWNWARD A FEW DEGREES. LOOK FOR MAX TEMPS TOMORROW IN THE 40S TO NEAR 50 F FOR THE HIGH VALLEYS...50S TO LOWER 60S FOR THE E PLAINS...WITH AREAS THAT RECEIVED EXTENSIVE SNOW COVER ON THE LOWER END. MOORE .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 256 PM MDT FRI APR 17 2015 OLD UPPER LOW OPENS UP AND PULLS AWAY TO THE EAST SAT NIGHT/SUNDAY. ANOTHER LOBE OF ENERGY ROTATING AROUND THE BACK SIDE OF THE UPPER LOW WILL SPREAD ANOTHER BAND OF SNOW SHOWERS INTO THE MTS/PALMER DIVIDE SATURDAY EVENING...AND INTO THE SOUTHEAST PLAINS SAT NIGHT/EARLY SUNDAY MORNING. OVERALL ACCUMULATIONS DO NOT LOOK LIKE THEY WILL BE THAT HEAVY...BUT A COUPLE INCHES ACROSS THE CENTRAL MTS AND PIKES PEAK REGION WILL BE POSSIBLE...WITH 1-2 ACROSS THE PALMER DIVIDE. IT WILL BE SOMEWHAT UNSTABLE...SO THERE IS ALWAYS A CHANCE FOR SOME LOCALLY HEAVY BURSTS OF SNOW...BUT THINK THESE SHOULD BE FAIRLY LOCALIZED. MEANWHILE PRECIPITATION WILL FALL AS RAIN ACROSS THE SE PLAINS EARLY BEFORE DIMINISHING BY LATE SUN MORNING. WINDS REALLY INCREASE ACROSS THE AREA FOR SUNDAY BEHIND THE SYSTEM WITH NORTH WINDS GUSTING TO 40 TO 50 MPH ACROSS THE PLAINS. FORTUNATELY MANY PLACES HAVE HAD SOME RAIN...WHICH SHOULD MINIMIZE BLOWING DUST CONCERNS SOME...AND COOLER AIR BEHIND THE SYSTEM SHOULD KEEP RELATIVE HUMIDITY VALUES FROM REACHING CRITICAL LEVELS WHICH SHOULD MITIGATE ANY FIRE WEATHER CONCERNS. NORTHWEST FLOW KEEPS UNSETTLED WEATHER OVER THE REGION FOR MONDAY AND TUESDAY WITH PRIMARILY AFTERNOON AND EVENING SNOW SHOWERS OVER THE MOUNTAINS. ANOTHER REINFORCING NORTHERLY SURGE MOVES THROUGH THE PLAINS ON MONDAY WHICH WILL ENHANCE EASTERLY UPSLOPE FLOW INTO THE SOUTHEAST MOUNTAINS. THIS WILL RESULT IN SCATTERED SNOW SHOWERS AS ANOTHER SHORTWAVE MOVES THROUGH NW FLOW ALOFT. GFS SPREADS THESE SHOWERS EASTWARD ONTO THE PLAINS DURING THE EVENING HOURS THOUGH PRECIPITATION WILL FALL MAINLY AS RAIN. WESTERN U.S UPPER RIDGE TRANSLATES EASTWARD FOR TUESDAY WITH SHOWERS STAYING MORE CONFINED TO THE MOUNTAINS. AGAIN...MAINLY LIGHT ACCUMULATIONS EXPECTED. ANOTHER TROF MOVES INTO THE WESTERN U.S FOR THE LATTER PART OF THE WEEK. UPPER RIDGE AXIS SHIFTS OVER CO FOR WEDNESDAY...THEN GRADUALLY INTO THE PLAINS THURS AND FRI AS THE UPPER TROF MOVES TOWARDS THE GREAT BASIN. LOTS OF VARIABILITY BETWEEN THE LONG RANGE MODELS ON TIMING...BUT BOTTOM LINE IS FOR INCREASING SOUTHWEST FLOW FOR THURSDAY AND FRIDAY...SPREADING A CHANCE OF SNOW SHOWERS INTO THE CONTDVD REGION BY LATE WEEK. TEMPERATURES REBOUND ACROSS THE PLAINS...THOUGH SOUTHEAST FLOW ADVECTS HIGHER DEW POINTS INTO THE PLAINS BRINGING A CHANCE FOR THUNDERSTORMS. AS SOUTHWEST FLOW ALOFT INCREASES...THIS SHOULD HELP DEVELOP A DRY LINE AND PUSH IT EASTWARD ACROSS THE PLAIN...WITH THUNDERSTORMS POSSIBLE ALONG AND TO ITS EAST THURS AFTERNOON. WILL HAVE TO WATCH THIS DEVELOPMENT AS DEEP LAYER SHEAR LOOKS FAVORABLE FOR STRONG TO SEVERE THUNDERSTORMS...IF SUFFICIENT MOISTURE CAN RETURN...BUT GIVEN THE UNCERTAINTIES IN THE EVOLUTION OF THE SYSTEM...THESE DETAILS ARE LIKELY TO EVOLVE OVER THE NEXT SEVERAL DAYS. -KT && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 256 PM MDT FRI APR 17 2015 DRY AIR HAS SPREAD IN ACROSS SOUTHERN AND EASTERN PORTIONS OF THE DISTRICT AROUND THE SOUTHERN AND EASTERN PERIPHERY OF THE UPPER LOW. THIS WILL KEEP VFR CONDITIONS AT THE TAF SITES. ISOLATED INSTABILITY SHOWERS WILL BE POSSIBLE IN THE VCNTY OF THE TAF SITES...THOUGH THESE WILL BE FAIRLY SPOTTY AND IF THEY DO IMPACT THE TERMINALS..WILL GENERALLY DO SOME BEFORE 03Z. WINDS WILL SHIFT OUT OF THE NORTH AT KCOS AND KPUB DURING THE EVENING HOURS AT AROUND 10-15 KTS...THEN BECOME LIGHT OVERNIGHT. WINDS ON SATURDAY WILL REMAIN NORTHERLY FOR ALL THREE TERMINALS AS THE UPPER LOW PULLS AWAY TO THE EAST. ANOTHER ROUND OF SHOWERS WILL BE POSSIBLE ACROSS THE MOUNTAINS. KCOS MAY SEE ANOTHER PASSING SHOWER IN THE VCNTY OF THE TERMINAL SAT AFTN...WHILE KPUB AND KALS HAVE A GREATER LIKELIHOOD OF STAYING DRY. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 AM MDT SATURDAY FOR COZ059-063- 066-081. WINTER WEATHER ADVISORY UNTIL 6 PM MDT SATURDAY FOR COZ058-060- 061. WINTER STORM WARNING UNTIL 6 PM MDT SATURDAY FOR COZ082. && $$ UPDATE...ROSE SHORT TERM...MOORE LONG TERM...KT AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
849 PM MDT FRI APR 17 2015 .UPDATE... ISSUED AT 844 PM MDT FRI APR 17 2015 MADE SOME ADJUSTMENTS TO THE WINTER HEADLINES BASED ON OBS...TRENDS AND LATEST MODEL GUIDANCE. LOOKS LIKE THE HEAVIEST AND MOST PERSISTENT PRECIP WILL BE OVER THE MTS NORTH OF HGWY 50 TONIGHT AND TOMORROW. SO...HAVE CANCELED THE ADVISORIES FOR THE SANGRES AND WETS. EXTENDED PIKES PEAK AND THE SAWATCH TIL 00Z SUN SINCE IT LOOKS LIKE PERIODS OF MODT SNOW WILL CONTINUE TOMORROW. TELLER MAY ALSO HAVE TO BE EXTENDED BUT GIVEN THE UNCERTAINTIES IN HOW THE BAND OF SNOW NORTH OF THE UPPER LOW WILL SET UP...WILL LEAVE THE ENDING TIME FOR SAT MORNING FOR NOW. HRRR HAS MOST OF THE HEAVIER QPF NORTH OF TELLER WHILE THE RAP AND NAM HAVE IT DIRECTLY OVER TELLER. SO...AMOUNTS ARE MOST UNCERTAIN OVER THE PIKES PEAK AREA BUT THE GOING ADVISORY COVERS THAT HAZARD FOR NOW. ROSE && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 256 PM MDT FRI APR 17 2015 CURRENTLY...THE UPPER LOW IS LOCATED OVER THE SW QUAD OF THE STATE THIS AFTERNOON...AND WAS WRAPPING DRY AIR UP INTO PORTIONS OF SOUTH CENTRAL AND SOUTHEAST CO EFFECTIVELY SHUTTING OFF PCPN AND EVEN CLOUD COVER FOR PORTIONS OF THE CWA. BEFORE THE DRY AIR MOVED IN...HEAVY SNOW WAS REPORTED OVER MANY OF THE AREA MTS AS WELL AS THE UPPER ARKANSAS RIVER BASIN...ALONG WITH SIGNIFICANT RAINFALL AMOUNTS ALL ALONG THE I25 CORRIDOR. CLOUD ENHANCEMENT WAS OCCURRING AS OF 3 PM OVER THE S MTS...SLOWLY SPREADING NORTH. FARTHER EAST...DRY AIR PUSHED INTO THE SE CORNER OF THE STATE AND HELPED TO PUSH THE SEVERE THREAT N AND NE. A FEW THUNDERSTORMS HAVE STRUGGLED ACROSS THE PLAINS THIS AFTN AS LOWER DEWPOINTS HAVE ROBBED LLVL ENERGY. TONIGHT AND TOMORROW...THE MAIN QUESTION IS WHERE WILL THE UPPER LOW GO. MODELS STILL INDICATE THAT IT WILL GRADUALLY MOVE NORTH INTO CENTRAL COLORADO THIS EVENING...THEN EDGE DUE EAST THROUGH TOMORROW AFTN. AFTER A BRIEF LULL...WHICH WILL MOST LIKELY HAVE CUSTOMERS SCRATCHING THEIR HEADS...ALL MODELS INCLUDING THE HI-RES OFFERINGS SHOW SHOWERS REDEVELOPING OVER THE PALMER DVD AND RAMPART RANGE...AS WELL AS THE CENTRAL MTS...N SANGRES AND WETS...THIS EVENING AND OVERNIGHT. ADDITIONAL SNOW AMOUNTS DO NOT LOOK AS SIGNIFICANT NOW AS THEY DID 12 HRS AGO...AND HANDLING OF THE HIGHLIGHTS WAS EXCEPTIONALLY TRICKY. DECIDED TO PUSH ALL ENDING TIMES OF HIGHLIGHTS TO 12Z TOMORROW MORNING...AND CONVERTED SOME OF THE ONGOING WARNINGS TO ADVISORIES. FURTHER ADJUSTMENTS TO THE POP AND HIGHLIGHT GRIDS WILL OCCUR UNDOUBTEDLY. AS FOR TEMPS...FRESH SNOW COVER FOR MUCH OF THE HIGHER TERRAIN AND HIGH VALLEYS WILL MAKE FOR A COLD NIGHT...AS WELL AS MODIFYING THE MAX TEMP TOMORROW DOWNWARD A FEW DEGREES. LOOK FOR MAX TEMPS TOMORROW IN THE 40S TO NEAR 50 F FOR THE HIGH VALLEYS...50S TO LOWER 60S FOR THE E PLAINS...WITH AREAS THAT RECEIVED EXTENSIVE SNOW COVER ON THE LOWER END. MOORE .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 256 PM MDT FRI APR 17 2015 OLD UPPER LOW OPENS UP AND PULLS AWAY TO THE EAST SAT NIGHT/SUNDAY. ANOTHER LOBE OF ENERGY ROTATING AROUND THE BACK SIDE OF THE UPPER LOW WILL SPREAD ANOTHER BAND OF SNOW SHOWERS INTO THE MTS/PALMER DIVIDE SATURDAY EVENING...AND INTO THE SOUTHEAST PLAINS SAT NIGHT/EARLY SUNDAY MORNING. OVERALL ACCUMULATIONS DO NOT LOOK LIKE THEY WILL BE THAT HEAVY...BUT A COUPLE INCHES ACROSS THE CENTRAL MTS AND PIKES PEAK REGION WILL BE POSSIBLE...WITH 1-2 ACROSS THE PALMER DIVIDE. IT WILL BE SOMEWHAT UNSTABLE...SO THERE IS ALWAYS A CHANCE FOR SOME LOCALLY HEAVY BURSTS OF SNOW...BUT THINK THESE SHOULD BE FAIRLY LOCALIZED. MEANWHILE PRECIPITATION WILL FALL AS RAIN ACROSS THE SE PLAINS EARLY BEFORE DIMINISHING BY LATE SUN MORNING. WINDS REALLY INCREASE ACROSS THE AREA FOR SUNDAY BEHIND THE SYSTEM WITH NORTH WINDS GUSTING TO 40 TO 50 MPH ACROSS THE PLAINS. FORTUNATELY MANY PLACES HAVE HAD SOME RAIN...WHICH SHOULD MINIMIZE BLOWING DUST CONCERNS SOME...AND COOLER AIR BEHIND THE SYSTEM SHOULD KEEP RELATIVE HUMIDITY VALUES FROM REACHING CRITICAL LEVELS WHICH SHOULD MITIGATE ANY FIRE WEATHER CONCERNS. NORTHWEST FLOW KEEPS UNSETTLED WEATHER OVER THE REGION FOR MONDAY AND TUESDAY WITH PRIMARILY AFTERNOON AND EVENING SNOW SHOWERS OVER THE MOUNTAINS. ANOTHER REINFORCING NORTHERLY SURGE MOVES THROUGH THE PLAINS ON MONDAY WHICH WILL ENHANCE EASTERLY UPSLOPE FLOW INTO THE SOUTHEAST MOUNTAINS. THIS WILL RESULT IN SCATTERED SNOW SHOWERS AS ANOTHER SHORTWAVE MOVES THROUGH NW FLOW ALOFT. GFS SPREADS THESE SHOWERS EASTWARD ONTO THE PLAINS DURING THE EVENING HOURS THOUGH PRECIPITATION WILL FALL MAINLY AS RAIN. WESTERN U.S UPPER RIDGE TRANSLATES EASTWARD FOR TUESDAY WITH SHOWERS STAYING MORE CONFINED TO THE MOUNTAINS. AGAIN...MAINLY LIGHT ACCUMULATIONS EXPECTED. ANOTHER TROF MOVES INTO THE WESTERN U.S FOR THE LATTER PART OF THE WEEK. UPPER RIDGE AXIS SHIFTS OVER CO FOR WEDNESDAY...THEN GRADUALLY INTO THE PLAINS THURS AND FRI AS THE UPPER TROF MOVES TOWARDS THE GREAT BASIN. LOTS OF VARIABILITY BETWEEN THE LONG RANGE MODELS ON TIMING...BUT BOTTOM LINE IS FOR INCREASING SOUTHWEST FLOW FOR THURSDAY AND FRIDAY...SPREADING A CHANCE OF SNOW SHOWERS INTO THE CONTDVD REGION BY LATE WEEK. TEMPERATURES REBOUND ACROSS THE PLAINS...THOUGH SOUTHEAST FLOW ADVECTS HIGHER DEW POINTS INTO THE PLAINS BRINGING A CHANCE FOR THUNDERSTORMS. AS SOUTHWEST FLOW ALOFT INCREASES...THIS SHOULD HELP DEVELOP A DRY LINE AND PUSH IT EASTWARD ACROSS THE PLAIN...WITH THUNDERSTORMS POSSIBLE ALONG AND TO ITS EAST THURS AFTERNOON. WILL HAVE TO WATCH THIS DEVELOPMENT AS DEEP LAYER SHEAR LOOKS FAVORABLE FOR STRONG TO SEVERE THUNDERSTORMS...IF SUFFICIENT MOISTURE CAN RETURN...BUT GIVEN THE UNCERTAINTIES IN THE EVOLUTION OF THE SYSTEM...THESE DETAILS ARE LIKELY TO EVOLVE OVER THE NEXT SEVERAL DAYS. -KT && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 256 PM MDT FRI APR 17 2015 DRY AIR HAS SPREAD IN ACROSS SOUTHERN AND EASTERN PORTIONS OF THE DISTRICT AROUND THE SOUTHERN AND EASTERN PERIPHERY OF THE UPPER LOW. THIS WILL KEEP VFR CONDITIONS AT THE TAF SITES. ISOLATED INSTABILITY SHOWERS WILL BE POSSIBLE IN THE VCNTY OF THE TAF SITES...THOUGH THESE WILL BE FAIRLY SPOTTY AND IF THEY DO IMPACT THE TERMINALS..WILL GENERALLY DO SOME BEFORE 03Z. WINDS WILL SHIFT OUT OF THE NORTH AT KCOS AND KPUB DURING THE EVENING HOURS AT AROUND 10-15 KTS...THEN BECOME LIGHT OVERNIGHT. WINDS ON SATURDAY WILL REMAIN NORTHERLY FOR ALL THREE TERMINALS AS THE UPPER LOW PULLS AWAY TO THE EAST. ANOTHER ROUND OF SHOWERS WILL BE POSSIBLE ACROSS THE MOUNTAINS. KCOS MAY SEE ANOTHER PASSING SHOWER IN THE VCNTY OF THE TERMINAL SAT AFTN...WHILE KPUB AND KALS HAVE A GREATER LIKELIHOOD OF STAYING DRY. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 AM MDT SATURDAY FOR COZ059-063- 066-081. WINTER WEATHER ADVISORY UNTIL 6 PM MDT SATURDAY FOR COZ058-060- 061. WINTER STORM WARNING UNTIL 6 PM MDT SATURDAY FOR COZ082. && $$ UPDATE...ROSE SHORT TERM...MOORE LONG TERM...KT AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
627 PM MDT FRI APR 17 2015 .UPDATE... ISSUED AT 613 PM MDT FRI APR 17 2015 LATEST HRRR IS MOVING THE PCPN OVER SERN CO INTO THE PALMER DIVIDE SHORTLY THEN NORTHWEST INTO THE URBAN CORRIDOR. HAVE INCREASED THE POPS THIS EVENING. PCPN WILL BE RAIN OR A RAIN/SNOW MIX. DUE TO THE CONVECTIVE NATURE OF THIS SYSTEM...AREAS OVER THE PALMER DIVIDE AND THE CHEYENNE RIDGE COULD PICK UP AN INCH OR TWO OF SNOW. ANY SNOWFALL THAT DEVELOPS ELSEWHERE ALONG THE URBAN CORRIDOR SHOULD BE AN INCH OR LESS. TORNADO WATCH REMAINS IN EFFECT FOR MORGAN....WASHINGTON...LOGAN...SEDGWICK AND PHILLIPS COUNTIES UNTIL MIDNIGHT. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 124 PM MDT FRI APR 17 2015 UPPER LEVEL LOW CENTERED OVER SOUTH CENTRAL COLORADO WILL SLOWLY SPIN NORTHEAST ACROSS THE STATE AND END UP OVER THE NORTHEAST CORNER SATURDAY AFTERNOON. DRIER AIR HAS ROTATED NORTH ACROSS THE AREA THIS AFTERNOON AND BROUGHT THE WIDESPREAD RAIN AND SNOW TO AN END. CLEARING DUE TO THE DRIER AIR HAS ALLOWED SOME WARMING. HIRES MODELS SHOWING SCATTERED CONVECTION FILLING IN DURING THE LATE AFTERNOON AND EVENING. WILL KEEP SCATTERED TO LIKELY POPS IN THE FORECAST THIS EVENING FOR THIS. ALREADY CANCELED THE ADVISORY WHERE THE SNOW ENDED IN PARK COUNTY AND THE PALMER DIVIDE. MAY BE ABLE TO CANCEL THE WINTER STORM WARNING AS WELL. WILL HOLD OFF FOR NOW AND SEE HOW MUCH CONVECTION FORMS. OUTSIDE OF CONVECTION...ADDITIONAL SNOWFALL ONCE THE DRY AIR MOVES THROUGH SHOULD BE LIGHT. COOLED HIGH TEMPERATURES ARE FEW DEGREES FOR SATURDAY WITH COOL AIR OVER US FROM THE UPPER LEVEL LOW. NORTHWEST FLOW BEHIND THE LOW COMBINED WITH STEEP LAPSE WILL PRODUCE SNOW SHOWERS OVER THE MOUNTAINS. INCREASED POPS FOR THIS. NEW SNOWFALL FOR THE MOUNTAINS SATURDAY WILL GENERALLY BE LESS THAN 4 INCHES...THOUGH A FEW FAVORED OROGRAPHIC AREAS COULD SEE A LITTLE MORE. FOR THE FRONT RANGE...DOWNSLOPE FLOW WILL LIMIT PRECIPITATION CHANCES...THOUGH IT SHOULD BE UNSTABLE ENOUGH FOR SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. THE BEST CHANCE WILL BE OVER THE PLAINS CLOSER TO THE LOW AND AWAY FROM DOWNSLOPE. AIRMASS WILL BE WARM ENOUGH FOR RAIN SATURDAY WITH SNOW CONFINED TO THE FOOTHILLS AND MOUNTAINS. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 124 PM MDT FRI APR 17 2015 THE ACTIVE PATTERN CONTINUES THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. SATURDAY NIGHT INTO SUNDAY THE UPPER LEVEL LOW CENTER WILL MAKES ITS WAY EAST OVER THE CO AND KS BORDER. THIS WILL BRING INCREASED NORTHERLY FLOW OVER NE COLORADO WITH A TROUGH OVER THE WEST WILL HELP BRING A SURGE OF COOLER AIR THAT WILL SPREAD SNOW SHOWERS OVER THE MOUNTAINS AND FOOTHILLS. THE TROUGH WILL PUSH EAST HELPING TO DRY OUT THE PLAINS KEEPING THE REGION COOLER UNDER MOSTLY CLOUDY SKIES. TEMPERATURES FOR SUNDAY WILL CONTINUE TO BE BELOW SEASONAL NORMALS WITH HIGHS IN THE UPPER 40S TO LOWER 50S. SUNDAY NIGHT INTO MONDAY STRONG NW WILL PREVAIL WITH A NW ORIENTED JET MOVING INTO NE COLORADO. INCREASED MOISTURE IN THE MID LEVELS WITH A SURFACE TROUGH WILL HELP TO KEEP SNOW IN THE MOUNTAINS AND SCATTERED RAINSHOWERS OVER THE PLAINS THROUGH MONDAY NIGHT INTO TUESDAY MORNING. WILL KEEP A SLIGHT CHANCE WITH THIS SYSTEM WITH A CHANCE IN THE MOUNTAINS WITH DECENT ASCENT. TEMPERATURES FOR MONDAY AND TUESDAY WILL SLOWLY INCREASE TO SEASONAL NORMALS BY TUESDAY AFTERNOON AS THE UPPER LEVEL RIDING MOVES IN ALONG WITH SURFACE HIGH PRESSURE. DOWNSLOPING WINDS OFF THE FOOTHILLS WILL HELP TO WARM TEMPERATURES OVER THE PLAINS INTO WEDNESDAY WHERE MODELS HAVE HIGH TEMPERATURES REACHING INTO THE UPPER 60S AND LOWER 70S. UPPER LEVEL FLOW TURNS SOUTHWESTERLY AHEAD OF THE NEXT DISTURBANCE OVER SOUTHERN CA. THE MODELS DIVERGE AT THIS POINT WITH THE GFS BRINGING PRECIPITATION BACK INTO THE MOUNTAINS BY WEDNESDAY EVENING AND THE EC 24 HOURS BEHIND. WILL KEEP A SLIGHT CHANCE IN THE GRIDS OR THIS PERIOD BUT WILL CONTINUE TO MONITOR MODEL TRENDS. && .AVIATION...(FOR THE TAFS THROUGH 06Z SATURDAY EVENING) ISSUED AT 613 PM MDT FRI APR 17 2015 ANOTHER AREA OF RAINSHOWERS...POSSIBLY MIXING WITH SNOW SHOWERS... APPROACHING FM THE SOUTH WILL MOVE NORTHWARD INTO THE URBAN CORRIDOR FM 02Z-06Z. PREVAILING MVFR CONDITIONS WITH THE POTENTIAL FOR IFR CIGS IF ANY HEAVY SHOWERS DEVELOP. PCPN WILL PERSIST THROUGH 10Z WITH THE POTENTIAL FOR SOME PATCHY FOG DEVELOPING TOWARDS 12Z. WINDS WILL BE OUT OF THE WEST/NORTHWEST THEN MOVE NORTHERLY AS A MID LEVEL CYCLONE MOVES IN JUST EAST OF THE AIRPORT....BACK TO WESTERLY SATURDAY MORNING. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 AM MDT SATURDAY FOR COZ033>036. && $$ UPDATE...COOPER SHORT TERM...MEIER LONG TERM...BOWEN AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS PUEBLO CO
424 PM MDT THU APR 16 2015 .UPDATE... ISSUED AT 423 PM MDT THU APR 16 2015 UPDATED THE FORECAST TO CANCEL THE RED FLAG FOR THE SAN LUIS VALLEY. SCATTERED SHOWERS ARE OVER THE VALLEY AND HUMIDITY IS NO LONGER CRITICAL. ROSE && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 356 PM MDT THU APR 16 2015 ...MODERATE TO HEAVY SNOW POSSIBLE FOR THE MOUNTAINS TONIGHT AND FRIDAY... ...CRITICAL FIRE WEATHER CONDITIONS POSSIBLE FOR THE FAR SOUTHEAST PLAINS AGAIN ON FRIDAY THOUGH THIS IS DEPENDENT ON HOW MUCH RAIN FALLS OVER THESE AREAS TONIGHT... ...MARGINAL POTENTIAL FOR SEVERE POSSIBLE FOR NORTHERN EL PASO AND KIOWA COUNTIES ON FRIDAY... STILL A HIGHLY DYNAMIC FORECAST AS MODELS HONE IN ON TRACK AND STRENGTH OF THE CLOSED LOW CURRENTLY ACROSS THE 4 CORNERS REGION. MODELS BOBBLE THE UPPER LOW SOUTHWARD A BIT THIS EVENING...THEN BACK TO THE NORTHEAST ACROSS THE CO/NM BORDER TONIGHT AS ENERGY ROTATES AROUND THE BASE OF THE UPPER LOW AND ACROSS CO. THEN IT MAKES STEADIER PROGRESS TO THE NORTHEAST INTO EAST CENTRAL CO ON FRIDAY. ALREADY SEEING ENHANCEMENT ACROSS THE SOUTHEAST MTS AND NRN NM AS THE NEXT IMPULSE APPROACHES. HRRR SEEMS TO HAVE PICKED UP ON THIS TREND FAIRLY WELL. WE SHOULD CONTINUE TO SEE SHOWERS FILL IN ACROSS THE SOUTHEAST MOUNTAINS...AND I-25 CORRIDOR...WITH SNOW LEVELS AROUND 6000-6500 FEET. SNOW LEVELS MAY ACTUALLY RISE A BIT FOR THE LOWER EASTERN SLOPES AS STRONG WAA OCCURS OVERNIGHT...WHICH COULD CAUSE A SWITCH BACK TO RAIN AT KCOS OVERNIGHT. HOWEVER...MTN AREAS SHOULD CONTINUE TO SEE SNOW AND HAVE EXPANDED ADVISORIES ACROSS MUCH OF THE MOUNTAIN AREAS. GIVEN THE CONVECTIVE POTENTIAL WITH THIS EVENINGS ROUND...CONCERNED THAT PORTIONS OF TELLER COUNTY COULD HIT WARNING CRITERIA...THOUGH DON`T THINK IT WILL BE WIDESPREAD ENOUGH ACROSS THE ZONE TO WARRANT AN UPGRADE. CENTRAL LAKE COUNTY COULD BE IN A SIMILAR BOAT...SO THESE AREAS WILL BE THE ONES TO WATCH CLOSELY. MEANWHILE...MODELS SHOW DEFORMATION BAND SNOW SPREADING WESTWARD INTO THE SOUTHWEST MOUNTAINS TONIGHT AND CONTINUING THROUGH FRIDAY. HAVE OPTED TO EXPAND ADVISORIES INTO THE LA GARITAS WHERE SNOW AMOUNTS ARE APPROACHING THE 6-12 INCH RANGE. STILL SOME QUESTION OVER THE EASTERN SAN JUANS THOUGH...COULD SEE A COUPLE INCHES FALL THERE TONIGHT...WITH ANOTHER 1-3 INCHES FALLING ON FRIDAY AS THE UPPER LOW WRAPS DEFORMATION BAND BACK TO THE SOUTHWEST ACROSS THE REGION. CONTEMPLATED AN ADVISORY FOR THIS REGION...BUT AM COMING UP SHY OF THE 6-12 INCHES NEEDED FOR A WINTER WX ADVISORY...THOUGH CERTAINLY SUBTLE CHANGES IN THE TRACK AND STRENGTH OF THE LOW COULD RESULT IN HEAVIER AMOUNTS FOR THIS REGION. STICKING TRUE TO THE GRIDS FOR NOW AND WILL LET LATER SHIFTS REASSESS. AS FOR SEVERE THUNDERSTORM POTENTIAL ACROSS THE PLAINS...APPEARS TIMING OF THE INITIAL WAVE THIS AFTERNOON WAS TOO QUICK FOR THE LOW LEVEL MOISTURE RETURN...AND NICE LINE OF THUNDERSTORMS HAS ALREADY DEVELOPED AND PUSHED EASTWARD INTO KANSAS. HOWEVER AS SURFACE WINDS HAVE VEERED MORE EASTERLY DUE TO FALLING SFC PRESSURES ACROSS NEW MEXICO...40S AND LOWER 50 DEW POINTS HAVE PULLED WESTWARD INTO THE FAR SOUTHEAST PLAINS. ACTIVITY INCREASING ACROSS NORTHERN NEW MEXICO MAY STILL HAVE A CHANCE TO INTERACT WITH THIS MOISTURE TO PRODUCE SOME ISOLATED SEVERE THUNDERSTORMS...WITH HAIL AND GUSTY WINDS THE PRIMARY STORM THREATS. OVERNIGHT...LATEST HRRR HINTS AT ANOTHER ROUND CLIPPING BY BACA COUNTY DURING THE 8Z TO 09Z TIMEFRAME...AND EVEN SOME SPOTTY THUNDERSTORMS POSSIBLE AS FAR WEST AS THE I-25 CORRIDOR. SO THOUGH MAIN THREAT FOR SEVERE THUNDERSTORMS WILL BE THIS EVENING...CAN`T RULE OUT A LOW GRADE SEVERE THREAT ACROSS THE FAR SOUTHEAST PLAINS EVEN DURING THE OVERNIGHT HOURS...THOUGH THUNDERSTORMS WILL TEND TO BE MORE ELEVATED. TOMORROW AS THE SURFACE LOW LIFTS INTO SOUTHEAST CO...COULD SEE SOME ISOLATED THUNDERSTORMS EVEN IN THE MORNING...AND LAPSE RATES WILL BE STEEP GIVEN THE MID LEVEL COOLING ASSOCIATED WITH THE SURFACE LOW. NAM12 SHOWS UP TO 1000 J/KG OF CAPE ACROSS NORTHERN PORTIONS OF THE SE PLAINS DURING THE MORNING...SO COULD HAVE ANOTHER CHANCE FOR SEVERE THUNDERSTORMS ON FRIDAY. BY AFTERNOON...DRY AIR SPREADS INTO THE SOUTHEAST PLAINS AS SURFACE LOW LIFTS NORTHWARD. THIS PUTS THE AXIS OF BEST INSTABILITY ALONG THE NORTHERN FRINGES OF THE SOUTHEAST PLAINS BY AFTERNOON...PRIMARILY NORTHEAST EL PASO AND KIOWA COUNTIES. THESE AREAS ARE OUTLOOKED FOR A MARGINAL SEVERE THREAT TOMORROW...AND THIS LOOKS ON TARGET. COULD SEE THIS MARGINAL THREAT SLIPPING SOUTHWARD A BIT TO ACCOUNT FOR ANY STRONG MORNING CONVECTION. BUT AS DRY AIR EXPANDS NORTHWARD...SO DOES THE POTENTIAL FOR CRITICAL FIRE WEATHER PARAMETERS...ESPECIALLY ACROSS LAS ANIMAS...BACA...BENT...PROWERS... AND OTERO COUNTIES. THE MITIGATING FACTOR WILL BE THE POTENTIAL FOR RAINFALL TO WET FUELS TONIGHT OVER THESE SAME ZONES. GIVEN THIS POTENTIAL...HAVE NOT GONE OUT WITH A FIRE WEATHER WATCH...BUT IF PRECIPITATION DOESN`T MATERIALIZE ACROSS A WIDESPREAD ENOUGH AREA ACROSS THESE REGION...THEN LATER SHIFTS MAY NEED TO HOIST A RED FLAG WARNING. -KT .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 356 PM MDT THU APR 16 2015 FRIDAY NIGHT THROUGH SATURDAY...MODELS HAVE SHIFTED A BIT OVER THE PST 24 HRS...BUT STILL REMAIN FAIRLY CONSISTENT WITH THE PLACEMENT AND PATH OF THE UPPER LOW. FRIDAY NIGHT THE LOW PRESSURE SYSTEM IS FORECAST TO BE CENTERED RIGHT OVER COLORADO...THEN OVER THE NEXT 24 HRS IT WILL WOBBLE A BIT BEFORE SLOWLY EXITING THE STATE VIA THE EASTERN BORDER. THIS PATTERN WOULD IMPLY THAT THE MTS...ESPECIALLY THE CONTDVD...WILL GET THE BRUNT OF SNOWFALL...MAINLY THROUGH FRIDAY NIGHT. THEREFORE...ONGOING WINTER HIGHLIGHTS RUNNING THROUGH 12Z SATURDAY LOOK REASONABLE. SNOW AMOUNTS WILL THEN TAPER OVER OVER THE DAY SATURDAY AS TEMPS BEGIN TO WARM AND THE SYSTEM WEAKENS. ISOLATED TO SCATTERED SHOWERS ARE FORECAST FOR THE REMAINDER OF THE LOWER ELEVATIONS...AND TEMPS DO NOT LOOK PARTICULARLY COLD WITH MIN TEMPS IN THE 30S TO AROUND 40 F FOR THE PLAINS...AND MAX TEMPS SATURDAY IN THE MID 50S TO LOWER 60S. SUNDAY AND MONDAY...THE UPPER SYSTEM WEAKENS AND EXITS TO THE EAST LATE SATURDAY...WITH BRISK NW FLOW ALOFT THEN SETTLING IN ACROSS THE STATE. A COUPLE OF UPPER SHORTWAVES ARE EXPECTED TO DROP DOWN ACROSS THE STATE ON BOTH DAYS...KEEPING THE THREAT OF SHOWER ACTIVITY FOR THE CWA IN PLACE. LOOK FOR SCATTERED SHOWERS OVER THE HIGHER TERRAIN...AND ISOLATED SHOWERS FOR THE PLAINS...WITH MAX TEMPS BOTH DAYS HOVERING IN THE 50S TO NEAR 60 F. TUESDAY THROUGH THURSDAY...CONFIDENCE IS FAIRLY LOW FOR WHAT HAPPENS BEYOND MONDAY...THOUGH LONG RANGE MODELS SEEM TO AGREE ON THE QUESTION MARK. A TEMPORARY RIDGE BUILDS INTO THE DESERT SW STARTING TUE...HELPING TO LOWERING PCPN CHANCES AS WELL AS BOOSTING MAX TEMPS FOR THE PLAINS BACK INTO THE 70S. TWO SEPARATE UPPER CLOSED LOW SYSTEMS APPROACH STARTING WED NIGHT...ONE OVER THE PAC NW AND THE OTHER OVER S CA...BUT THIS PATTERN WILL MOST LIKELY GO THROUGH MULTIPLE ADJUSTMENTS BEFORE THEN. MOORE && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 356 PM MDT THU APR 16 2015 CURRENTLY...VFR TO MVFR CONDITIONS FOR THE THREE MAIN TAF SITES OF KCOS...KPUB AND KALS AS WELL AS FOR MUCH OF THE LOWER ELEVATIONS. FOR ELEVATIONS ABOVE ROUGHLY 7000 FT...IFR CONDITIONS PREVAILED DUE TO EXTENSIVE LOWER CLOUD COVER AND ONGOING SNOW SHOWERS. THE UPPER LOW WILL SLOWLY MOVE FROM THE SW QUAD TO THE CENTRAL PORTIONS OF THE STATE OVER THE NEXT 24 HRS...BRINGING WAVES OF RAIN/SNOW SHOWERS TO THE LOWER ELEVATIONS AND SNOW...HEAVY AT TIMES...TO THE MTS. EXPECT MVFR CONDITIONS FOR KPUB AND KALS OVER THE NEXT 24 HRS. KCOS IS EXPECTED TO DIP INTO IFR CONDITIONS THIS EVENING...THEN BRIEFLY DROP DOWN INTO LIFR AFTER 11Z TOMORROW MORN. CONDITIONS ACROSS THE HIGHER TERRAIN AND MT PASSES WILL REMAIN IFR TO LIFR. MOORE && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 AM MDT SATURDAY FOR COZ059-062- 063-074-075. WINTER WEATHER ADVISORY UNTIL 6 PM MDT FRIDAY FOR COZ076>079. WINTER STORM WARNING UNTIL 6 AM MDT SATURDAY FOR COZ058-060-061- 072-073-080-082. WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT FRIDAY NIGHT FOR COZ066. WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT FRIDAY NIGHT FOR COZ081. WINTER WEATHER ADVISORY UNTIL 6 PM MDT FRIDAY FOR COZ084. && $$ UPDATE...ROSE SHORT TERM...KT LONG TERM...MOORE AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
357 PM MDT THU APR 16 2015 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 356 PM MDT THU APR 16 2015 ...MODERATE TO HEAVY SNOW POSSIBLE FOR THE MOUNTAINS TONIGHT AND FRIDAY... ...CRITICAL FIRE WEATHER CONDITIONS POSSIBLE FOR THE FAR SOUTHEAST PLAINS AGAIN ON FRIDAY THOUGH THIS IS DEPENDENT ON HOW MUCH RAIN FALLS OVER THESE AREAS TONIGHT... ...MARGINAL POTENTIAL FOR SEVERE POSSIBLE FOR NORTHERN EL PASO AND KIOWA COUNTIES ON FRIDAY... STILL A HIGHLY DYNAMIC FORECAST AS MODELS HONE IN ON TRACK AND STRENGTH OF THE CLOSED LOW CURRENTLY ACROSS THE 4 CORNERS REGION. MODELS BOBBLE THE UPPER LOW SOUTHWARD A BIT THIS EVENING...THEN BACK TO THE NORTHEAST ACROSS THE CO/NM BORDER TONIGHT AS ENERGY ROTATES AROUND THE BASE OF THE UPPER LOW AND ACROSS CO. THEN IT MAKES STEADIER PROGRESS TO THE NORTHEAST INTO EAST CENTRAL CO ON FRIDAY. ALREADY SEEING ENHANCEMENT ACROSS THE SOUTHEAST MTS AND NRN NM AS THE NEXT IMPULSE APPROACHES. HRRR SEEMS TO HAVE PICKED UP ON THIS TREND FAIRLY WELL. WE SHOULD CONTINUE TO SEE SHOWERS FILL IN ACROSS THE SOUTHEAST MOUNTAINS...AND I-25 CORRIDOR...WITH SNOW LEVELS AROUND 6000-6500 FEET. SNOW LEVELS MAY ACTUALLY RISE A BIT FOR THE LOWER EASTERN SLOPES AS STRONG WAA OCCURS OVERNIGHT...WHICH COULD CAUSE A SWITCH BACK TO RAIN AT KCOS OVERNIGHT. HOWEVER...MTN AREAS SHOULD CONTINUE TO SEE SNOW AND HAVE EXPANDED ADVISORIES ACROSS MUCH OF THE MOUNTAIN AREAS. GIVEN THE CONVECTIVE POTENTIAL WITH THIS EVENINGS ROUND...CONCERNED THAT PORTIONS OF TELLER COUNTY COULD HIT WARNING CRITERIA...THOUGH DON`T THINK IT WILL BE WIDESPREAD ENOUGH ACROSS THE ZONE TO WARRANT AN UPGRADE. CENTRAL LAKE COUNTY COULD BE IN A SIMILAR BOAT...SO THESE AREAS WILL BE THE ONES TO WATCH CLOSELY. MEANWHILE...MODELS SHOW DEFORMATION BAND SNOW SPREADING WESTWARD INTO THE SOUTHWEST MOUNTAINS TONIGHT AND CONTINUING THROUGH FRIDAY. HAVE OPTED TO EXPAND ADVISORIES INTO THE LA GARITAS WHERE SNOW AMOUNTS ARE APPROACHING THE 6-12 INCH RANGE. STILL SOME QUESTION OVER THE EASTERN SAN JUANS THOUGH...COULD SEE A COUPLE INCHES FALL THERE TONIGHT...WITH ANOTHER 1-3 INCHES FALLING ON FRIDAY AS THE UPPER LOW WRAPS DEFORMATION BAND BACK TO THE SOUTHWEST ACROSS THE REGION. CONTEMPLATED AN ADVISORY FOR THIS REGION...BUT AM COMING UP SHY OF THE 6-12 INCHES NEEDED FOR A WINTER WX ADVISORY...THOUGH CERTAINLY SUBTLE CHANGES IN THE TRACK AND STRENGTH OF THE LOW COULD RESULT IN HEAVIER AMOUNTS FOR THIS REGION. STICKING TRUE TO THE GRIDS FOR NOW AND WILL LET LATER SHIFTS REASSESS. AS FOR SEVERE THUNDERSTORM POTENTIAL ACROSS THE PLAINS...APPEARS TIMING OF THE INITIAL WAVE THIS AFTERNOON WAS TOO QUICK FOR THE LOW LEVEL MOISTURE RETURN...AND NICE LINE OF THUNDERSTORMS HAS ALREADY DEVELOPED AND PUSHED EASTWARD INTO KANSAS. HOWEVER AS SURFACE WINDS HAVE VEERED MORE EASTERLY DUE TO FALLING SFC PRESSURES ACROSS NEW MEXICO...40S AND LOWER 50 DEW POINTS HAVE PULLED WESTWARD INTO THE FAR SOUTHEAST PLAINS. ACTIVITY INCREASING ACROSS NORTHERN NEW MEXICO MAY STILL HAVE A CHANCE TO INTERACT WITH THIS MOISTURE TO PRODUCE SOME ISOLATED SEVERE THUNDERSTORMS...WITH HAIL AND GUSTY WINDS THE PRIMARY STORM THREATS. OVERNIGHT...LATEST HRRR HINTS AT ANOTHER ROUND CLIPPING BY BACA COUNTY DURING THE 8Z TO 09Z TIMEFRAME...AND EVEN SOME SPOTTY THUNDERSTORMS POSSIBLE AS FAR WEST AS THE I-25 CORRIDOR. SO THOUGH MAIN THREAT FOR SEVERE THUNDERSTORMS WILL BE THIS EVENING...CAN`T RULE OUT A LOW GRADE SEVERE THREAT ACROSS THE FAR SOUTHEAST PLAINS EVEN DURING THE OVERNIGHT HOURS...THOUGH THUNDERSTORMS WILL TEND TO BE MORE ELEVATED. TOMORROW AS THE SURFACE LOW LIFTS INTO SOUTHEAST CO...COULD SEE SOME ISOLATED THUNDERSTORMS EVEN IN THE MORNING...AND LAPSE RATES WILL BE STEEP GIVEN THE MID LEVEL COOLING ASSOCIATED WITH THE SURFACE LOW. NAM12 SHOWS UP TO 1000 J/KG OF CAPE ACROSS NORTHERN PORTIONS OF THE SE PLAINS DURING THE MORNING...SO COULD HAVE ANOTHER CHANCE FOR SEVERE THUNDERSTORMS ON FRIDAY. BY AFTERNOON...DRY AIR SPREADS INTO THE SOUTHEAST PLAINS AS SURFACE LOW LIFTS NORTHWARD. THIS PUTS THE AXIS OF BEST INSTABILITY ALONG THE NORTHERN FRINGES OF THE SOUTHEAST PLAINS BY AFTERNOON...PRIMARILY NORTHEAST EL PASO AND KIOWA COUNTIES. THESE AREAS ARE OUTLOOKED FOR A MARGINAL SEVERE THREAT TOMORROW...AND THIS LOOKS ON TARGET. COULD SEE THIS MARGINAL THREAT SLIPPING SOUTHWARD A BIT TO ACCOUNT FOR ANY STRONG MORNING CONVECTION. BUT AS DRY AIR EXPANDS NORTHWARD...SO DOES THE POTENTIAL FOR CRITICAL FIRE WEATHER PARAMETERS...ESPECIALLY ACROSS LAS ANIMAS...BACA...BENT...PROWERS... AND OTERO COUNTIES. THE MITIGATING FACTOR WILL BE THE POTENTIAL FOR RAINFALL TO WET FUELS TONIGHT OVER THESE SAME ZONES. GIVEN THIS POTENTIAL...HAVE NOT GONE OUT WITH A FIRE WEATHER WATCH...BUT IF PRECIPITATION DOESN`T MATERIALIZE ACROSS A WIDESPREAD ENOUGH AREA ACROSS THESE REGION...THEN LATER SHIFTS MAY NEED TO HOIST A RED FLAG WARNING. -KT .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 356 PM MDT THU APR 16 2015 FRIDAY NIGHT THROUGH SATURDAY...MODELS HAVE SHIFTED A BIT OVER THE PST 24 HRS...BUT STILL REMAIN FAIRLY CONSISTENT WITH THE PLACEMENT AND PATH OF THE UPPER LOW. FRIDAY NIGHT THE LOW PRESSURE SYSTEM IS FORECAST TO BE CENTERED RIGHT OVER COLORADO...THEN OVER THE NEXT 24 HRS IT WILL WOBBLE A BIT BEFORE SLOWLY EXITING THE STATE VIA THE EASTERN BORDER. THIS PATTERN WOULD IMPLY THAT THE MTS...ESPECIALLY THE CONTDVD...WILL GET THE BRUNT OF SNOWFALL...MAINLY THROUGH FRIDAY NIGHT. THEREFORE...ONGOING WINTER HIGHLIGHTS RUNNING THROUGH 12Z SATURDAY LOOK REASONABLE. SNOW AMOUNTS WILL THEN TAPER OVER OVER THE DAY SATURDAY AS TEMPS BEGIN TO WARM AND THE SYSTEM WEAKENS. ISOLATED TO SCATTERED SHOWERS ARE FORECAST FOR THE REMAINDER OF THE LOWER ELEVATIONS...AND TEMPS DO NOT LOOK PARTICULARLY COLD WITH MIN TEMPS IN THE 30S TO AROUND 40 F FOR THE PLAINS...AND MAX TEMPS SATURDAY IN THE MID 50S TO LOWER 60S. SUNDAY AND MONDAY...THE UPPER SYSTEM WEAKENS AND EXITS TO THE EAST LATE SATURDAY...WITH BRISK NW FLOW ALOFT THEN SETTLING IN ACROSS THE STATE. A COUPLE OF UPPER SHORTWAVES ARE EXPECTED TO DROP DOWN ACROSS THE STATE ON BOTH DAYS...KEEPING THE THREAT OF SHOWER ACTIVITY FOR THE CWA IN PLACE. LOOK FOR SCATTERED SHOWERS OVER THE HIGHER TERRAIN...AND ISOLATED SHOWERS FOR THE PLAINS...WITH MAX TEMPS BOTH DAYS HOVERING IN THE 50S TO NEAR 60 F. TUESDAY THROUGH THURSDAY...CONFIDENCE IS FAIRLY LOW FOR WHAT HAPPENS BEYOND MONDAY...THOUGH LONG RANGE MODELS SEEM TO AGREE ON THE QUESTION MARK. A TEMPORARY RIDGE BUILDS INTO THE DESERT SW STARTING TUE...HELPING TO LOWERING PCPN CHANCES AS WELL AS BOOSTING MAX TEMPS FOR THE PLAINS BACK INTO THE 70S. TWO SEPARATE UPPER CLOSED LOW SYSTEMS APPROACH STARTING WED NIGHT...ONE OVER THE PAC NW AND THE OTHER OVER S CA...BUT THIS PATTERN WILL MOST LIKELY GO THROUGH MULTIPLE ADJUSTMENTS BEFORE THEN. MOORE && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 356 PM MDT THU APR 16 2015 CURRENTLY...VFR TO MVFR CONDITIONS FOR THE THREE MAIN TAF SITES OF KCOS...KPUB AND KALS AS WELL AS FOR MUCH OF THE LOWER ELEVATIONS. FOR ELEVATIONS ABOVE ROUGHLY 7000 FT...IFR CONDITIONS PREVAILED DUE TO EXTENSIVE LOWER CLOUD COVER AND ONGOING SNOW SHOWERS. THE UPPER LOW WILL SLOWLY MOVE FROM THE SW QUAD TO THE CENTRAL PORTIONS OF THE STATE OVER THE NEXT 24 HRS...BRINGING WAVES OF RAIN/SNOW SHOWERS TO THE LOWER ELEVATIONS AND SNOW...HEAVY AT TIMES...TO THE MTS. EXPECT MVFR CONDITIONS FOR KPUB AND KALS OVER THE NEXT 24 HRS. KCOS IS EXPECTED TO DIP INTO IFR CONDITIONS THIS EVENING...THEN BRIEFLY DROP DOWN INTO LIFR AFTER 11Z TOMORROW MORN. CONDITIONS ACROSS THE HIGHER TERRAIN AND MT PASSES WILL REMAIN IFR TO LIFR. MOORE && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 AM MDT SATURDAY FOR COZ059-062- 063. WINTER WEATHER ADVISORY UNTIL 6 PM MDT FRIDAY FOR COZ076>079. WINTER STORM WARNING UNTIL 6 AM MDT SATURDAY FOR COZ058-060-061- 072-073-080-082. RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR COZ224. WINTER WEATHER ADVISORY UNTIL 6 AM MDT SATURDAY FOR COZ074-075. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT MDT FRIDAY NIGHT FOR COZ066. WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT FRIDAY NIGHT FOR COZ081. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MDT FRIDAY FOR COZ084. && $$ SHORT TERM...KT LONG TERM...MOORE AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
308 PM MDT THU APR 16 2015 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 257 PM MDT THU APR 16 2015 WATER VAPOR SATELLITE IMAGERY SHOWING THE UPPER LEVEL LOW CENTERED OVER THE FOUR CORNERS AT THIS TIME WITH A SHORT WAVE ROTATING AROUND IT OVER NORTH CENTRAL NEW MEXICO. THIS WAVE WILL ROTATE NORTH OVER EASTERN COLORADO TONIGHT BRINGING WIDESPREAD RAIN AND SNOW TO THE AREA. IN ADDITION TO THE WAVE PASSING ACROSS THE AREA...UPSLOPE WINDS WILL REMAIN STRONG AT 20 TO 40 KNOTS ALONG THE FRONT RANGE. EXPECT MODERATE TO HEAVY SNOW THROUGH THE NIGHT WITH SNOWFALL RATES 1 TO 2 INCHES PER HOUR AT TIMES IN THE FOOTHILLS AND MOUNTAINS. LAPSE RATES ARE ALSO STEEP...SO A FEW THUNDERSTORMS WILL BE POSSIBLE TONIGHT. WILL MENTION A SLIGHT CHANCE IN THE FORECAST FOR THE FRONT RANGE AND EASTERN PLAINS TONIGHT AND FRIDAY. MODELS GENERALLY SHOWING 1 TO 2 INCHES OF PRECIPITATION THROUGH FRIDAY MORNING WITH THIS SYSTEM...A LITTLE MORE OVER LARIMER COUNTY. SO 1 TO 3 FEET LOOKS ON TRACK FOR SNOWFALL AMOUNTS IN THE FOOTHILLS AND FRONT RANGE MOUNTAINS. EXPECT A RAIN/SNOW MIX THIS EVENING BETWEEN 5000 TO 6000 FEET WITH OCCASIONAL HEAVY SNOW UNDER THE STRONGEST SHOWERS. EASTERLY WINDS AROUND THE LOW WILL CONTINUE TO PUMP MOISTURE INTO THE AREA ALONG WITH WARMER AIR. THIS IS EXPECTED TO CHANGE SNOW TO RAIN ACROSS THE DENVER AREA OVERNIGHT. BY FRIDAY MORNING...EXPECT RAIN FOR MOST PLACES UNDER 6000 FEET. MAY SEE UP TO 6 INCHES OF SLUSHY SNOW PRIOR TO CHANGING TO RAIN IN THE DENVER AREA OVERNIGHT...POSSIBLY A LITTLE MORE NEAR THE FOOTHILLS AND PALMER DIVIDE. WILL ISSUE AN ADVISORY FOR PARK COUNTY AND PALMER DIVIDE WHERE AN ADDITIONAL 4 TO 8 INCHES WILL BE POSSIBLE. ON FRIDAY...THE UPPER LEVEL LOW WILL LIFT INTO COLORADO. AT THE SURFACE...A LOW WILL MOVE EAST ACROSS EASTERN COLORADO. TO THE NORTH AND EAST OF THE SURFACE LOW...SURFACE BASED CAPES CLIMB TO AROUND 2000 J/KG BASED ON THE 18Z NAM. WITH STRONG SHEAR IN PLACE...THIS WILL BE ENOUGH INSTABILITY FOR A CHANCE OF SEVERE THUNDERSTORMS...MAIN THREATS WILL BE LARGE HAIL UP TO GOLF BALL SIZE AND TORNADOS. RIGHT NOW APPEARS THE BEST CHANCE WILL BE FROM GREELEY TO LIMON AND EASTWARD...THOUGH THIS WILL DEPEND ON WHERE THE LOW TRACKS. FOR THE FOOTHILLS AND MOUNTAINS...STILL LOOKS LIKE IT WILL STAY COLD ENOUGH FOR SNOW THROUGH THE DAY. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 257 PM MDT THU APR 16 2015 THE FIRST PART OF THE LONG TERM FORECAST HINGES OF THE LOCATION AND MOVEMENT OF THE 500 MB UPPER LEVEL LOW PRESSURE SYSTEM. THE MODELS ARE IN PRETTY GOOD AGREEMENT...HOWEVER JUST A SLIGHT DEVIATION IN THE UPPER LOW TRACK WOULD AFFECT PRECIPITATION AND SNOWFALL AMOUNTS ACROSS NORTH CENTRAL AND NORTHEASTERN COLORADO. THE ECMWF HAS BEEN VERY CONSISTENT AND HAS THE 500 MB LOW CENTERED JUST WEST OF COLORADO SPRINGS AT 00Z SATURDAY. THE GFS AND NAM MODELS HAVE THE CENTER NEAR CANON CITY WHICH IS APPROXIMATELY 75 SOUTH OF THE PREVIOUS TWO RUNS. THESE MODELS THEN TRACK THE LOW TO NEAR DENVER BY 12Z SATURDAY MORNING. AS THE LOW MOVES NORTH DENVER SHOULD SEE A DECREASE IN PRECIPITATION...HOWEVER THE MOUNTAINS AND FOOTHILLS NEAR THE WYOMING BORDER COULD STILL BE UNDER THE GUN AS WRAP AROUND PRECIP WRAPS INTO THE REGION FROM THE NORTH. THE 15Z RUC JUST CAME IN AND SHOWS THE UPPER LOW TAKING A MORE SOUTHERLY TRACK ACROSS SOUTHERN COLORADO. THIS TRACK COULD PROLONG THE PRECIP EVENT BUT FOR NOW WILL GO WITH THE CONSENSUS OF THE GFS...ECMWF AND NAM. PRECIPITATION CHANCES DECREASE SATURDAY NIGHT INTO SUNDAY AS THE UPPER LOW WEAKENS AND MOVES INTO THE CENTRAL PLAINS STATES AND A NORTHWEST FLOW ALOFT DEVELOPS OVER THE STATE. UNSETTLED WEATHER WILL CONTINUE ACROSS NORTH CENTRAL AND NORTHEASTERN COLORADO THROUGH MONDAY AS RESIDUAL MOISTURE COMBINES WITH INSTABILITY DUE TO DAYTIME HEATING. A WEAK SURGE IN THE NORTHWEST FLOW COULD ENHANCE PRECIPITATION CHANCES. WARMER AND DRIER WEATHER WILL RETURN TO THE REGION ON TUESDAY AS UPPER LEVEL HIGH PRESSURE BUILDS OVER THE ROCKY MOUNTAIN REGION. && .AVIATION...(FOR THE TAFS THROUGH 00Z FRIDAY LATE AFTERNOON) ISSUED AT 257 PM MDT THU APR 16 2015 RAIN AND SNOW WILL CONTINUE THROUGH THE EVENING AND EVENTUALLY TURN TO RAIN BY FRIDAY MORNING. VISIBILITY WILL FALL TO A QUARTER MILE AT TIMES IN THE HEAVIER SNOW. CEILINGS WILL BE UNDER 1000 FEET AND ONLY OCCASIONAL BE HIGHER THAN THAT. NORTHERLY WINDS WILL PREVAIL AT SPEEDS LESS THAN 20 KNOTS. SNOW ACCUMULATION AT KDEN IS EXPECTED TO STAY BELOW 3 INCHES...WITH UP TO 6 INCHES POSSIBLE AT KAPA AND KBJC. IN ADDITION TO THE RAIN/SNOW...ISOLATED THUNDERSTORMS ARE EXPECTED TO FORM...MAINLY THIS EVENING THEN AGAIN FRIDAY AFTERNOON. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MDT FRIDAY FOR COZ037-041. WINTER STORM WARNING UNTIL 6 AM MDT SATURDAY FOR COZ033>036. && $$ SHORT TERM...MEIER LONG TERM...JK AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1137 AM MDT THU APR 16 2015 .UPDATE... ISSUED AT 1134 AM MDT THU APR 16 2015 RATHER NARROW BAND OF HEAVIER SNOW STILL PERSISTED ACROSS A PORTION OF WEST-CENTRAL CO LATE THIS MORNING AS THE FIRST IN SERIES OF DISTURBANCES ROTATED AROUND A FOUR CORNERS LOW AND NORTH INTO CO. SNOW HAS TAKEN A BREAK AT MONTROSE BUT CONTINUED AT GRAND JCT AT 11 AM. SOME AREAS IN THE GRAND VALLEY HAVE SEEN LOCALLY UP TO AN INCH OR TWO ON GRASSY AREAS PER PUBLIC REPORTS...BUT EXPECT THIS TO MELT THIS AFTERNOON AS THIS BAND MOVES OUT AND TEMPS WARM. HOWEVER...DID UPDATE TO LOWER THE HIGH TEMPS TODAY ACROSS THE CENTRAL FORECAST AREA DUE TO THIS MORNING`S CLOUDS AND PRECIP HAMPERING THE DIURNAL WARM-UP. 16Z RAP SHOWS ANOTHER WAVE ROTATING NORTH TROUGH CENTRAL CO TONIGHT. EXPECT THIS TO BRING ANOTHER ROUND OF HEAVIER PRECIP FOR AT LEAST THE CENTRAL MTNS AND NRN MTNS AS EASTERLY FLOW ALSO BRINGS MORE MOISTURE ACROSS THE DIVIDE. THE 12Z NAM AND GFS SHOW THE MAIN UPPER LOW OVER SW CO/NW NM FRI MORNING. UPDATE ISSUED AT 936 AM MDT THU APR 16 2015 GRAND JCT RADAR INDICATED AN AREA OF ENHANCED PRECIPITATION ACROSS WEST-CENTRAL CO THIS MORNING. MUCH OF THIS PRECIP WAS SNOW PER PUBLIC REPORTS AND WEBCAM IMAGES. NOT EXPECTING ANY LONG-LASTING ACCUMULATIONS IN THESE VALLEYS THOUGH PERIODS OF HEAVIER SNOW MAY TEMPORARILY WHITEN GRASSY SURFACES. HI-RESOLUTION HRRR AND RAP MODELS SHOW THIS AREA DECREASING...OR AT LEAST SLIDING NORTH AND NORTHEAST...BY LATE MORNING. EXPECT TO SEE COVERAGE INCREASE ACROSS ALL OF THE CENTRAL AND NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON AS CONVECTIVE INSTABILITY KICKS IN EVEN MORE. LET THE FREEZE WARNING EXPIRE AT 9 AM THIS MORNING. SOME AREAS WHERE SNOW IS OCCURRING MAY STILL BE IN THE UPPER 20S FOR A BIT LONGER THOUGH...LIKE DELTA/MONTROSE/PAONIA AREAS. FREEZE WATCH REMAINS FOR THE CORTEZ-YELLOWJACKET AREA EARLY FRI MORNING. UPDATE ISSUED AT 613 AM MDT THU APR 16 2015 SOCIAL MEDIA REPORTS OF HOWLING WINDS IN THE STEAMBOAT SPRINGS AREA HAVE BEEN RECEIVED EARLY THIS MORNING...PEAK GUSTS ON SENSORS IN THE AREA SHOWING 25-35 MPH SO FAR THIS MORNING. PATTERN IS SETTING UP FOR A POTENTIAL DOWNSLOPE WIND EVENT IN THIS REGION LATER THIS AFTERNOON AND TONIGHT. STRONG H7 FLOW AROUND NORTH SIDE OF THE LOW EXPECTED TO EXCEED 50 KTS AND WE HAVE SEEN THIS TYPE OF FLOW IN THE PAST GENERATE STRONG DOWNSLOPE WINDS IN THE STEAMBOAT AND ZIRKEL WILDERNESS AREAS. TRACK OF THE UPPER LOW WILL PLAY CRITICAL ROLE AND MODELS STILL A BIT OUT OF PHASE IN EXACT PATH...SO WILL CONTINUE TO MONITOR AND ADVISE LATER SHIFTS OF THIS POTENTIAL. IN THE MEANTIME...BOOSTED SPEEDS UP A FEW CATEGORIES FOR TODAY WITH GUSTS UP TO 50 MPH FOR THE HILLS AND GUST TO UP TO 45 FOR THE VALLEYS. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 416 AM MDT THU APR 16 2015 SPRING IN THE CENTRAL ROCKIES IS REARING ITS UGLY HEAD AS TEMPERATURES THIS MORNING HAVE DIPPED BELOW FREEZING IN MANY LOCATIONS WHICH HAVE ALREADY BEGUN THEIR GROWING SEASONS...WHILE OTHERS (THE EASTERN UINTAS) HAVE ALREADY SEEN A DECENT AMOUNT OF ACCUMULATING SNOW. A LARGE CLOSED LOW IS CURRENTLY OVER SOUTHEAST UTAH AND WILL SLOWLY PROGRESS SOUTH TO THE FOUR CORNERS LATER THIS MORNING. MODELS ARE IN GOOD AGREEMENT THAT SIGNIFICANT SNOW IS GOING TO FALL AT ELEVATIONS MAINLY HIGHER THAN 9000 FT STARTING THIS AFTERNOON ACROSS THE WEST CENTRAL COLORADO MOUNTAINS AND WILL CONTINUE TO FALL OVER THE EASTERN UINTAS. THOUGH WINDS WILL NOT BE FAVORABLE FOR CONSTANT SNOWFALL DURING THE ENTIRE TIME PERIOD OF THE WINTER HAZARDS...WHEN THE DIRECTION IS RIGHT COMBINED WITH LIFTING DUE TO THE PASSING CLOSED LOW...HEAVY WET SNOW WILL PILE UP QUICKLY AT THESE HIGHER LOCATIONS. HAVE KEPT A CLOSE EYE ON THE MOISTURE FIELDS OVER THE LAST FEW DAYS AND HAVE SEEN THE FORECAST MODELS INCREASE MOISTURE FROM THE SOUTH AND NOW INCREASE MOISTURE ACROSS WESTERN CO AND EASTERN UT AS IT WRAPS AROUND THE SLOWLY PROGRESSING CLOSED LOW. THE SLOW MOVEMENT AND DYNAMICS OF THE LOW SHOULD BE EFFECTIVE IN OVERCOMING THE MOUNTAIN SHADOW EFFECT. SPEC HUMIDITY VALUES ARE NOW BEING PROGGED TO REACH AND EXCEED 4 G/KG WHICH IS RATHER SIGNIFICANT WITH SUCH A COLD SYSTEM IN APRIL. SNOW LEVEL IS DEFINITELY A CHALLENGE AND AM EXPECTING NORTHERN COLORADO VALLEYS TO SEE MAINLY RAIN AND A RAIN/SNOW MIX WITH LITTLE ACCUMULATION. AN UPTICK IN ACTIVITY IS EXPECTED THIS AFTERNOON AND EVENING...BUT ALL FORECAST MODELS REALLY PICK UP COVERAGE IN ACTIVITY FRIDAY AFTERNOON. CONDITIONS NORTH OF I-70 TODAY WILL BE BREEZY AND WET MUCH OF TODAY. ELSEWHERE WILL RECEIVE SCATTERED SHOWERS WITH THE EXCEPTION OF THE CENTRAL MOUNTAINS WHICH WILL SEE DETERIORATING CONDITIONS TODAY. ADDED NORTHERN SAN JUANS TO A WINTER STORM WATCH STARTING TONIGHT AS WE ANTICIPATE FLOW CHANGING TO WEST NORTHWESTERLY. STRONG NORTHERLY FLOW FRIDAY EVENING WILL ALSO BE FAVORABLE FOR THIS AREA TO RECEIVE HEAVY SNOW IF THE LOW STAYS ON TRACK. CONFIDENCE IS MODERATE ON CURRENT SOLUTIONS EVEN A COUPLE DAYS OUT DUE TO THE LOW TRACKING SO SLOWLY ACROSS THE REGION. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 416 AM MDT THU APR 16 2015 MEANDERING LOW WILL CONTINUE TO WREAK HAVOC ON THE FORECAST AS WE START OFF THIS EXTENDED PERIOD. DEEP NORTHERLY FLOW ON THE BACK SIDE OF THE...EXPECTED TO BE EXITING LOW PRESSURE SYSTEM...MAY KEEP LOCALLY HEAVY SNOW FALLING ACROSS THE NORTHWEST SAN JUAN MOUNTAINS AND OTHER FAVORED NORTH FACING SLOPES IN WESTERN COLORADO. THIS SYSTEM LOOKS TO LINGER OVER THE AREA UNTIL MIDDAY SATURDAY...BEFORE A KICKING WAVE DROPS INTO MONTANA LATE SATURDAY AFTERNOON AND EVENING. THIS SYSTEM SHOULD KICK THE LOW OUT INTO THE PLAINS WITH SOMEWHAT MOIST NW FLOW HOLDING IN PLACE THROUGH THE REMAINDER OF THE WEEKEND. SO EXPECT UNSETTLED CONDITIONS TO CONTINUE OVER THE NORTHERN AND CENTRAL MOUNTAINS WITH ADDITIONAL LATE SEASON SNOWFALL ANTICIPATED...ESPECIALLY ABOVE THE 9K LEVEL. SLIGHT INCREASE IN HEIGHTS EXPECTED AS WE MOVE INTO THE NEW WORK WEEK...WHICH WILL MODIFY TEMPS UP A BIT. HOWEVER...ENOUGH PACIFIC MOISTURE STREAMING INTO THE REGION TO KEEP ISOLATED TO SCATTERED POPS ROLLING THROUGHOUT THE PERIOD...GENERALLY FOCUSED ON THE HIGHER TERRAIN. ANOTHER STRONG CLOSED LOW BEING ADVERTISED BY BOTH THE GFS AND ECMWF LATE NEXT WEEK PROMISES TO BRING MORE WIDESPREAD PRECIPITATION TO THE REGION AS WE CLOSE THE WEEK OUT. EXPECT TEMPS TO BE RUNNING NEAR TO SLIGHTLY BELOW NORMAL THROUGH THIS PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1054 AM MDT THU APR 16 2015 A STRONG LOW PRESSURE SYSTEM NEAR THE FOUR CORNERS AREA THIS AFTERNOON AND THIS EVENING...WILL MEANDER SLOWLY INTO SOUTH- CENTRAL COLORADO BY MIDDAY FRIDAY. EXPECT WIDESPREAD SHOWERS ACROSS THE REGION BY THIS AFTERNOON...WITH LOCALLY HEAVY SNOW EXPECTED OVER THE MOUNTAINS THROUGH SATURDAY. SNOW WILL SWITCH OVER TO RAIN IN THE LOWER VALLEYS AT TIMES THIS AFTERNOON. CIGS AND VSBY WILL DROP IN SHOWERS WITH AREAS OF MVFR AND IFR CONDS. THESE POOR CONDITIONS WILL BECOME MORE WIDESPREAD LATER TONIGHT. MOUNTAINS WILL BECOME OBSCURED... ESPECIALLY NEAR SHOWERS. GUSTY EASTERLY WINDS CAN BE EXPECTED ACROSS WESTERN COLORADO AND EASTERN UTAH THROUGH FRIDAY MORNING. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...WINTER WEATHER ADVISORY UNTIL NOON MDT SATURDAY FOR COZ004-009- 013. WINTER STORM WARNING UNTIL NOON MDT SATURDAY FOR COZ010-012. WINTER STORM WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING FOR COZ018. FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR COZ021. UT...WINTER STORM WARNING UNTIL 6 AM MDT SATURDAY FOR UTZ023. && $$ UPDATE...JAD SHORT TERM...JAM LONG TERM...JDC AVIATION...EH
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1054 AM MDT THU APR 16 2015 .UPDATE... ISSUED AT 936 AM MDT THU APR 16 2015 GRAND JCT RADAR INDICATED AN AREA OF ENHANCED PRECIPITATION ACROSS WEST-CENTRAL CO THIS MORNING. MUCH OF THIS PRECIP WAS SNOW PER PUBLIC REPORTS AND WEBCAM IMAGES. NOT EXPECTING ANY LONG-LASTING ACCUMULATIONS IN THESE VALLEYS THOUGH PERIODS OF HEAVIER SNOW MAY TEMPORARILY WHITEN GRASSY SURFACES. HI-RESOLUTION HRRR AND RAP MODELS SHOW THIS AREA DECREASING...OR AT LEAST SLIDING NORTH AND NORTHEAST...BY LATE MORNING. EXPECT TO SEE COVERAGE INCREASE ACROSS ALL OF THE CENTRAL AND NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON AS CONVECTIVE INSTABILITY KICKS IN EVEN MORE. LET THE FREEZE WARNING EXPIRE AT 9 AM THIS MORNING. SOME AREAS WHERE SNOW IS OCCURRING MAY STILL BE IN THE UPPER 20S FOR A BIT LONGER THOUGH...LIKE DELTA/MONTROSE/PAONIA AREAS. FREEZE WATCH REMAINS FOR THE CORTEZ-YELLOWJACKET AREA EARLY FRI MORNING. UPDATE ISSUED AT 613 AM MDT THU APR 16 2015 SOCIAL MEDIA REPORTS OF HOWLING WINDS IN THE STEAMBOAT SPRINGS AREA HAVE BEEN RECEIVED EARLY THIS MORNING...PEAK GUSTS ON SENSORS IN THE AREA SHOWING 25-35 MPH SO FAR THIS MORNING. PATTERN IS SETTING UP FOR A POTENTIAL DOWNSLOPE WIND EVENT IN THIS REGION LATER THIS AFTERNOON AND TONIGHT. STRONG H7 FLOW AROUND NORTH SIDE OF THE LOW EXPECTED TO EXCEED 50 KTS AND WE HAVE SEEN THIS TYPE OF FLOW IN THE PAST GENERATE STRONG DOWNSLOPE WINDS IN THE STEAMBOAT AND ZIRKEL WILDERNESS AREAS. TRACK OF THE UPPER LOW WILL PLAY CRITICAL ROLE AND MODELS STILL A BIT OUT OF PHASE IN EXACT PATH...SO WILL CONTINUE TO MONITOR AND ADVISE LATER SHIFTS OF THIS POTENTIAL. IN THE MEANTIME...BOOSTED SPEEDS UP A FEW CATEGORIES FOR TODAY WITH GUSTS UP TO 50 MPH FOR THE HILLS AND GUST TO UP TO 45 FOR THE VALLEYS. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 416 AM MDT THU APR 16 2015 SPRING IN THE CENTRAL ROCKIES IS REARING ITS UGLY HEAD AS TEMPERATURES THIS MORNING HAVE DIPPED BELOW FREEZING IN MANY LOCATIONS WHICH HAVE ALREADY BEGUN THEIR GROWING SEASONS...WHILE OTHERS (THE EASTERN UINTAS) HAVE ALREADY SEEN A DECENT AMOUNT OF ACCUMULATING SNOW. A LARGE CLOSED LOW IS CURRENTLY OVER SOUTHEAST UTAH AND WILL SLOWLY PROGRESS SOUTH TO THE FOUR CORNERS LATER THIS MORNING. MODELS ARE IN GOOD AGREEMENT THAT SIGNIFICANT SNOW IS GOING TO FALL AT ELEVATIONS MAINLY HIGHER THAN 9000 FT STARTING THIS AFTERNOON ACROSS THE WEST CENTRAL COLORADO MOUNTAINS AND WILL CONTINUE TO FALL OVER THE EASTERN UINTAS. THOUGH WINDS WILL NOT BE FAVORABLE FOR CONSTANT SNOWFALL DURING THE ENTIRE TIME PERIOD OF THE WINTER HAZARDS...WHEN THE DIRECTION IS RIGHT COMBINED WITH LIFTING DUE TO THE PASSING CLOSED LOW...HEAVY WET SNOW WILL PILE UP QUICKLY AT THESE HIGHER LOCATIONS. HAVE KEPT A CLOSE EYE ON THE MOISTURE FIELDS OVER THE LAST FEW DAYS AND HAVE SEEN THE FORECAST MODELS INCREASE MOISTURE FROM THE SOUTH AND NOW INCREASE MOISTURE ACROSS WESTERN CO AND EASTERN UT AS IT WRAPS AROUND THE SLOWLY PROGRESSING CLOSED LOW. THE SLOW MOVEMENT AND DYNAMICS OF THE LOW SHOULD BE EFFECTIVE IN OVERCOMING THE MOUNTAIN SHADOW EFFECT. SPEC HUMIDITY VALUES ARE NOW BEING PROGGED TO REACH AND EXCEED 4 G/KG WHICH IS RATHER SIGNIFICANT WITH SUCH A COLD SYSTEM IN APRIL. SNOW LEVEL IS DEFINITELY A CHALLENGE AND AM EXPECTING NORTHERN COLORADO VALLEYS TO SEE MAINLY RAIN AND A RAIN/SNOW MIX WITH LITTLE ACCUMULATION. AN UPTICK IN ACTIVITY IS EXPECTED THIS AFTERNOON AND EVENING...BUT ALL FORECAST MODELS REALLY PICK UP COVERAGE IN ACTIVITY FRIDAY AFTERNOON. CONDITIONS NORTH OF I-70 TODAY WILL BE BREEZY AND WET MUCH OF TODAY. ELSEWHERE WILL RECEIVE SCATTERED SHOWERS WITH THE EXCEPTION OF THE CENTRAL MOUNTAINS WHICH WILL SEE DETERIORATING CONDITIONS TODAY. ADDED NORTHERN SAN JUANS TO A WINTER STORM WATCH STARTING TONIGHT AS WE ANTICIPATE FLOW CHANGING TO WEST NORTHWESTERLY. STRONG NORTHERLY FLOW FRIDAY EVENING WILL ALSO BE FAVORABLE FOR THIS AREA TO RECEIVE HEAVY SNOW IF THE LOW STAYS ON TRACK. CONFIDENCE IS MODERATE ON CURRENT SOLUTIONS EVEN A COUPLE DAYS OUT DUE TO THE LOW TRACKING SO SLOWLY ACROSS THE REGION. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 416 AM MDT THU APR 16 2015 MEANDERING LOW WILL CONTINUE TO WREAK HAVOC ON THE FORECAST AS WE START OFF THIS EXTENDED PERIOD. DEEP NORTHERLY FLOW ON THE BACK SIDE OF THE...EXPECTED TO BE EXITING LOW PRESSURE SYSTEM...MAY KEEP LOCALLY HEAVY SNOW FALLING ACROSS THE NORTHWEST SAN JUAN MOUNTAINS AND OTHER FAVORED NORTH FACING SLOPES IN WESTERN COLORADO. THIS SYSTEM LOOKS TO LINGER OVER THE AREA UNTIL MIDDAY SATURDAY...BEFORE A KICKING WAVE DROPS INTO MONTANA LATE SATURDAY AFTERNOON AND EVENING. THIS SYSTEM SHOULD KICK THE LOW OUT INTO THE PLAINS WITH SOMEWHAT MOIST NW FLOW HOLDING IN PLACE THROUGH THE REMAINDER OF THE WEEKEND. SO EXPECT UNSETTLED CONDITIONS TO CONTINUE OVER THE NORTHERN AND CENTRAL MOUNTAINS WITH ADDITIONAL LATE SEASON SNOWFALL ANTICIPATED...ESPECIALLY ABOVE THE 9K LEVEL. SLIGHT INCREASE IN HEIGHTS EXPECTED AS WE MOVE INTO THE NEW WORK WEEK...WHICH WILL MODIFY TEMPS UP A BIT. HOWEVER...ENOUGH PACIFIC MOISTURE STREAMING INTO THE REGION TO KEEP ISOLATED TO SCATTERED POPS ROLLING THROUGHOUT THE PERIOD...GENERALLY FOCUSED ON THE HIGHER TERRAIN. ANOTHER STRONG CLOSED LOW BEING ADVERTISED BY BOTH THE GFS AND ECMWF LATE NEXT WEEK PROMISES TO BRING MORE WIDESPREAD PRECIPITATION TO THE REGION AS WE CLOSE THE WEEK OUT. EXPECT TEMPS TO BE RUNNING NEAR TO SLIGHTLY BELOW NORMAL THROUGH THIS PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1054 AM MDT THU APR 16 2015 A STRONG LOW PRESSURE SYSTEM NEAR THE FOUR CORNERS AREA THIS AFTERNOON AND THIS EVENING...WILL MEANDER SLOWLY INTO SOUTH- CENTRAL COLORADO BY MIDDAY FRIDAY. EXPECT WIDESPREAD SHOWERS ACROSS THE REGION BY THIS AFTERNOON...WITH LOCALLY HEAVY SNOW EXPECTED OVER THE MOUNTAINS THROUGH SATURDAY. SNOW WILL SWITCH OVER TO RAIN IN THE LOWER VALLEYS AT TIMES THIS AFTERNOON. CIGS AND VSBY WILL DROP IN SHOWERS WITH AREAS OF MVFR AND IFR CONDS. THESE POOR CONDITIONS WILL BECOME MORE WIDESPREAD LATER TONIGHT. MOUNTAINS WILL BECOME OBSCURED... ESPECIALLY NEAR SHOWERS. GUSTY EASTERLY WINDS CAN BE EXPECTED ACROSS WESTERN COLORADO AND EASTERN UTAH THROUGH FRIDAY MORNING. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...WINTER WEATHER ADVISORY UNTIL NOON MDT SATURDAY FOR COZ004-009- 013. WINTER STORM WARNING UNTIL NOON MDT SATURDAY FOR COZ010-012. WINTER STORM WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING FOR COZ018. FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR COZ021. UT...WINTER STORM WARNING UNTIL 6 AM MDT SATURDAY FOR UTZ023. && $$ UPDATE...JAD SHORT TERM...JAM LONG TERM...JDC AVIATION...EH
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
938 AM MDT THU APR 16 2015 .UPDATE... ISSUED AT 936 AM MDT THU APR 16 2015 GRAND JCT RADAR INDICATED AN AREA OF ENHANCED PRECIPITATION ACROSS WEST-CENTRAL CO THIS MORNING. MUCH OF THIS PRECIP WAS SNOW PER PUBLIC REPORTS AND WEBCAM IMAGES. NOT EXPECTING ANY LONG-LASTING ACCUMULATIONS IN THESE VALLEYS THOUGH PERIODS OF HEAVIER SNOW MAY TEMPORARILY WHITEN GRASSY SURFACES. HI-RESOLUTION HRRR AND RAP MODELS SHOW THIS AREA DECREASING...OR AT LEAST SLIDING NORTH AND NORTHEAST...BY LATE MORNING. EXPECT TO SEE COVERAGE INCREASE ACROSS ALL OF THE CENTRAL AND NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON AS CONVECTIVE INSTABILITY KICKS IN EVEN MORE. LET THE FREEZE WARNING EXPIRE AT 9 AM THIS MORNING. SOME AREAS WHERE SNOW IS OCCURRING MAY STILL BE IN THE UPPER 20S FOR A BIT LONGER THOUGH...LIKE DELTA/MONTROSE/PAONIA AREAS. FREEZE WATCH REMAINS FOR THE CORTEZ-YELLOWJACKET AREA EARLY FRI MORNING. UPDATE ISSUED AT 613 AM MDT THU APR 16 2015 SOCIAL MEDIA REPORTS OF HOWLING WINDS IN THE STEAMBOAT SPRINGS AREA HAVE BEEN RECEIVED EARLY THIS MORNING...PEAK GUSTS ON SENSORS IN THE AREA SHOWING 25-35 MPH SO FAR THIS MORNING. PATTERN IS SETTING UP FOR A POTENTIAL DOWNSLOPE WIND EVENT IN THIS REGION LATER THIS AFTERNOON AND TONIGHT. STRONG H7 FLOW AROUND NORTH SIDE OF THE LOW EXPECTED TO EXCEED 50 KTS AND WE HAVE SEEN THIS TYPE OF FLOW IN THE PAST GENERATE STRONG DOWNSLOPE WINDS IN THE STEAMBOAT AND ZIRKEL WILDERNESS AREAS. TRACK OF THE UPPER LOW WILL PLAY CRITICAL ROLE AND MODELS STILL A BIT OUT OF PHASE IN EXACT PATH...SO WILL CONTINUE TO MONITOR AND ADVISE LATER SHIFTS OF THIS POTENTIAL. IN THE MEANTIME...BOOSTED SPEEDS UP A FEW CATEGORIES FOR TODAY WITH GUSTS UP TO 50 MPH FOR THE HILLS AND GUST TO UP TO 45 FOR THE VALLEYS. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 416 AM MDT THU APR 16 2015 SPRING IN THE CENTRAL ROCKIES IS REARING ITS UGLY HEAD AS TEMPERATURES THIS MORNING HAVE DIPPED BELOW FREEZING IN MANY LOCATIONS WHICH HAVE ALREADY BEGUN THEIR GROWING SEASONS...WHILE OTHERS (THE EASTERN UINTAS) HAVE ALREADY SEEN A DECENT AMOUNT OF ACCUMULATING SNOW. A LARGE CLOSED LOW IS CURRENTLY OVER SOUTHEAST UTAH AND WILL SLOWLY PROGRESS SOUTH TO THE FOUR CORNERS LATER THIS MORNING. MODELS ARE IN GOOD AGREEMENT THAT SIGNIFICANT SNOW IS GOING TO FALL AT ELEVATIONS MAINLY HIGHER THAN 9000 FT STARTING THIS AFTERNOON ACROSS THE WEST CENTRAL COLORADO MOUNTAINS AND WILL CONTINUE TO FALL OVER THE EASTERN UINTAS. THOUGH WINDS WILL NOT BE FAVORABLE FOR CONSTANT SNOWFALL DURING THE ENTIRE TIME PERIOD OF THE WINTER HAZARDS...WHEN THE DIRECTION IS RIGHT COMBINED WITH LIFTING DUE TO THE PASSING CLOSED LOW...HEAVY WET SNOW WILL PILE UP QUICKLY AT THESE HIGHER LOCATIONS. HAVE KEPT A CLOSE EYE ON THE MOISTURE FIELDS OVER THE LAST FEW DAYS AND HAVE SEEN THE FORECAST MODELS INCREASE MOISTURE FROM THE SOUTH AND NOW INCREASE MOISTURE ACROSS WESTERN CO AND EASTERN UT AS IT WRAPS AROUND THE SLOWLY PROGRESSING CLOSED LOW. THE SLOW MOVEMENT AND DYNAMICS OF THE LOW SHOULD BE EFFECTIVE IN OVERCOMING THE MOUNTAIN SHADOW EFFECT. SPEC HUMIDITY VALUES ARE NOW BEING PROGGED TO REACH AND EXCEED 4 G/KG WHICH IS RATHER SIGNIFICANT WITH SUCH A COLD SYSTEM IN APRIL. SNOW LEVEL IS DEFINITELY A CHALLENGE AND AM EXPECTING NORTHERN COLORADO VALLEYS TO SEE MAINLY RAIN AND A RAIN/SNOW MIX WITH LITTLE ACCUMULATION. AN UPTICK IN ACTIVITY IS EXPECTED THIS AFTERNOON AND EVENING...BUT ALL FORECAST MODELS REALLY PICK UP COVERAGE IN ACTIVITY FRIDAY AFTERNOON. CONDITIONS NORTH OF I-70 TODAY WILL BE BREEZY AND WET MUCH OF TODAY. ELSEWHERE WILL RECEIVE SCATTERED SHOWERS WITH THE EXCEPTION OF THE CENTRAL MOUNTAINS WHICH WILL SEE DETERIORATING CONDITIONS TODAY. ADDED NORTHERN SAN JUANS TO A WINTER STORM WATCH STARTING TONIGHT AS WE ANTICIPATE FLOW CHANGING TO WEST NORTHWESTERLY. STRONG NORTHERLY FLOW FRIDAY EVENING WILL ALSO BE FAVORABLE FOR THIS AREA TO RECEIVE HEAVY SNOW IF THE LOW STAYS ON TRACK. CONFIDENCE IS MODERATE ON CURRENT SOLUTIONS EVEN A COUPLE DAYS OUT DUE TO THE LOW TRACKING SO SLOWLY ACROSS THE REGION. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 416 AM MDT THU APR 16 2015 MEANDERING LOW WILL CONTINUE TO WREAK HAVOC ON THE FORECAST AS WE START OFF THIS EXTENDED PERIOD. DEEP NORTHERLY FLOW ON THE BACK SIDE OF THE...EXPECTED TO BE EXITING LOW PRESSURE SYSTEM...MAY KEEP LOCALLY HEAVY SNOW FALLING ACROSS THE NORTHWEST SAN JUAN MOUNTAINS AND OTHER FAVORED NORTH FACING SLOPES IN WESTERN COLORADO. THIS SYSTEM LOOKS TO LINGER OVER THE AREA UNTIL MIDDAY SATURDAY...BEFORE A KICKING WAVE DROPS INTO MONTANA LATE SATURDAY AFTERNOON AND EVENING. THIS SYSTEM SHOULD KICK THE LOW OUT INTO THE PLAINS WITH SOMEWHAT MOIST NW FLOW HOLDING IN PLACE THROUGH THE REMAINDER OF THE WEEKEND. SO EXPECT UNSETTLED CONDITIONS TO CONTINUE OVER THE NORTHERN AND CENTRAL MOUNTAINS WITH ADDITIONAL LATE SEASON SNOWFALL ANTICIPATED...ESPECIALLY ABOVE THE 9K LEVEL. SLIGHT INCREASE IN HEIGHTS EXPECTED AS WE MOVE INTO THE NEW WORK WEEK...WHICH WILL MODIFY TEMPS UP A BIT. HOWEVER...ENOUGH PACIFIC MOISTURE STREAMING INTO THE REGION TO KEEP ISOLATED TO SCATTERED POPS ROLLING THROUGHOUT THE PERIOD...GENERALLY FOCUSED ON THE HIGHER TERRAIN. ANOTHER STRONG CLOSED LOW BEING ADVERTISED BY BOTH THE GFS AND ECMWF LATE NEXT WEEK PROMISES TO BRING MORE WIDESPREAD PRECIPITATION TO THE REGION AS WE CLOSE THE WEEK OUT. EXPECT TEMPS TO BE RUNNING NEAR TO SLIGHTLY BELOW NORMAL THROUGH THIS PERIOD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 416 AM MDT THU APR 16 2015 A STRONG LOW PRESSURE SYSTEM WILL BE DROPPING SOUTH INTO THE FOUR CORNERS AREA TODAY AND WILL MEANDER SLOWLY ENE ACROSS COLORADO FOR THE NEXT 24 HOURS. EXPECT WIDESPREAD SHOWERS TO DEVELOP ACROSS THE REGION BY THIS AFTERNOON...WITH LOCALLY HEAVY SNOW EXPECTED OVER THE MOUNTAINS THROUGH SATURDAY. CIGS WILL BE DROPPING THROUGHOUT THE REGION WITH AREAS OF MVFR AND IFR CONDS ANTICIPATED LATER TONIGHT. MOUNTAINS WILL BECOME OBSCURED...ESPECIALLY NEAR SHOWERS. GUSTY EASTERLY WINDS CAN BE EXPECTED ACROSS WESTERN COLORADO AND EASTERN UTAH THROUGH FRIDAY MORNING. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...WINTER WEATHER ADVISORY UNTIL NOON MDT SATURDAY FOR COZ004-009- 013. WINTER STORM WARNING UNTIL NOON MDT SATURDAY FOR COZ010-012. WINTER STORM WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING FOR COZ018. FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR COZ021. UT...WINTER STORM WARNING UNTIL 6 AM MDT SATURDAY FOR UTZ023. && $$ UPDATE...JAD SHORT TERM...JAM LONG TERM...JDC AVIATION...JDC
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
430 AM EDT THU APR 16 2015 .SYNOPSIS...08Z WATER VAPOR AND H4 RAP ANALYSIS SHOW TWO DISTINCT AND SEPARATE UPPER LEVEL FLOWS ACROSS NORTH AMERICA THIS MORNING. THE NORTHERN STREAM FLOW HAS SHIFTED WELL TO THE NORTH AND NOW RUNS IN A GENERALLY ZONAL CONFIGURATION TO THE NORTH OF THE US/CANADIAN BORDER. A SECOND BELT OF SOUTHERN STREAM WESTERLIES CROSSES FROM THE CENTRAL PACIFIC...OVER MEXICO...AND ACROSS THE GULF OF MEXICO INTO THE SOUTHEASTERN CONUS/FL PENINSULA. THIS SOUTHERN STREAM FLOW IS TRANSPORTING ABUNDANT MID/UPPER LEVEL MOISTURE INTO THE REGION PER WV IMAGERY. BETWEEN THESE TO BELTS OF WESTERLIES...THE FLOW BECOMES MUCH WEAKER...WITH A LARGE CUTOFF LOW NOW TRAPPED OVER THE INTER- MOUNTAIN WEST...AND DOWNSTREAM RIDING OVER THE EASTERN CONUS. THE UPPER LOW IS CURRENTLY CENTERED AND SPINNING NEAR THE 4-CORNERS REGION...AND IS NOT SHOWN TO MOVE MUCH AT ALL DURING THE NEXT 24 HOURS BY THE MAJORITY OF THE AVAILABLE GUIDANCE. WITHIN THE SOUTHERN STREAM FLOW WE SEE A SERIES OF WEAK IMPULSES RIDING ALONG THE NORTHERN GULF COAST AHEAD OF AN 80-100KT JET STREAK...EXTENDING OVER NORTHERN MEXICO TO THE WESTERN GULF OF MEXICO. SYNOPTIC LIFT ASSOCIATED WITH THESE DISTURBANCES...AND ALONG THE LEADING NOSE OF THE JET ARE FORCING PERIODIC PULSES OF CONVECTION OVER THE NORTH-CENTRAL GULF OF MEXICO. SOME OF THIS LIFT IS NOW BEGINNING TO REACH AS FAR EAST AS THE NE GOMEX WHERE HIGHER LEVEL RADAR RETURNS ARE BEGINNING TO BLOSSOM SOUTH OF APALACHICOLA. THE RAP/HRRR SEEM TO HAVE A DECENT HANDLE ON THIS ACTIVITY AND HAVE FOLLOWED THEIR ENSEMBLE SOLUTION CLOSELY FOR THE RAIN CHANCES INTO OUR NORTHERN MARINE ZONES/LEVY COUNTY THROUGH THE NEXT 4-8 HOURS. AT THE SURFACE...HIGH PRESSURE WEDGING DOWN THE EASTERN SEABOARD INTO THE SOUTHEAST CONUS HAS PUSHED A WEAK FRONTAL BOUNDARY DOWN INTO NORTH-CENTRAL FLORIDA. THE BOUNDARY IS SUBTLE...BUT CAN BE FOUND MOST EASILY BY SURFACE DEWPOINT ANALYSIS...WHERE SLIGHTLY "DRIER" AIR HAS WORKED INTO AREAS NORTH OF THE I-4 CORRIDOR. THIS QUASI-STATIONARY BOUNDARY IS LIKELY TO BE THE FOCUS (ALONG WITH EVENTUAL SEA-BREEZE INTERACTIONS) FOR NUMEROUS SHOWERS AND STORMS OVER PORTIONS OF THE REGION DURING THE SECOND HALF OF TODAY. && .SHORT TERM (TODAY THROUGH FRIDAY)... TODAY... GENERALLY SPEAK THE MAJORITY OF THE SYNOPTIC LIFT AND ASSOCIATED CONVECTION WITH THE SOUTHERN STREAM IMPULSES WILL REMAIN TO OUR NORTHWEST TODAY. HOWEVER...THE SOUTHERN STREAM WILL CONTINUE TO PROVIDE ABUNDANT COLUMN MOISTURE. THE SHOWERS AND STORMS IN OUR FORECAST AREA WILL BE RELATED TO LOWER LEVEL FOCUS ALONG A QUASI- STATIONARY FRONTAL BOUNDARY STRETCHED ACROSS NORTH-CENTRAL FLORIDA...AND ITS EVENTUAL INTERACTION WITH ANY SEA-BREEZE THAT IS ABLE TO BECOME ESTABLISHED. THE SEA-BREEZE SHOULD BE MOST DEFINED TO THE SOUTH OF THE FRONTAL BOUNDARY FROM THE TAMPA BAY AREA...AND ALONG THE SUN COAST. FOR THE MORNING HOURS...WILL BE TRACKING SHOWER ACTIVITY CROSSING THE NORTHEAST GULF OF MEXICO AHEAD OF A LEADING SOUTHERN STREAM IMPULSE. AS MENTIONED IN THE SYNOPSIS...THE LATEST RAP/HRRR SEEM TO BE HANDLING THE CURRENT CONVECTION FAIRLY WELL AND FOLLOWED THEIR SOLUTIONS THIS MORNING...BRINGING CHANCE POPS INTO LEVY COUNTY. BOTH SHOW THIS ACTIVITY JUST BARELY REACHING LEVY...BUT A SLIGHT SOUTHERN BIAS TO THE RADAR RETURNS COMPARED TO THE GUIDANCE SUGGESTS THAT THEY MAY BE INITIALLY TOO FAR NORTH. A FEW OTHER SHOWERS HAVE BEEN FORMING EARLY THIS MORNING OVER LEE COUNTY ALONG A RESIDUAL OUTFLOW BOUNDARY FROM WEDNESDAY EVENING CONVECTION. THESE SHOWERS ARE FINALLY PASSING OFF THE COAST INTO THE GULF. TOWARD MIDDAY AND INTO THE AFTERNOON HOURS...CONVECTION ALLOWING GUIDANCE AND PARAMETERIZED GUIDANCE ENSEMBLES ALL SUGGEST A RATHER ACTIVE SECOND HALF OF THE DAY IN TERMS OF SHOWERS AND STORMS. ACTUALLY AM VERY IMPRESSED WITH THE DEGREE OF AGREEMENT WITHIN THE CONVECTION ALLOWING MODELS AS TO STORM INITIATION AND EVOLUTION. APPEARS STORMS WILL BEGIN TO FIRE BY EARLY AFTERNOON ALONG THE FRONTAL BOUNDARY GENERALLY ALONG THE I-4 CORRIDOR...AND BY THAT I JUST MEAN CENTRAL FLORIDA. BY LATER IN THE AFTERNOON/EARLY EVENING...APPEARS STORMS BEGIN TO ALIGN MORE NORTH TO SOUTH PARALLEL TO THE COAST...WITH THE HEAVIEST ACTIVITY SHIFTING INTO OUR SOUTH- CENTRAL ZONES...WHERE THE FRONTAL ZONES MOST ACTIVELY INTERACTS WITH THE SUNCOAST SEA-BREEZE. THIS IS A TOUGH FORECAST ALONG THE IMMEDIATE COAST AS THE SEA-BREEZE IS NOT STRONG TODAY...BUT MAY BE JUST ENOUGH TO KEEP CONVECTION AWAY FROM THE BEACHES. FOR NOW...HAVE THE HIGHEST POPS ALONG AND INLAND FORM I-75...BUT CERTAINLY EXPECTING TO SEE SOME STORMS FURTHER WEST TO THE COAST...ESPECIALLY FROM THE TAMPA BAY AREA...UP INTO PASCO/HERNANDO COUNTIES. STORMS SHOULD EVENTUALLY EVOLVE FURTHER INLAND AND SOUTH AS THE EVENING PROGRESSES...GIVEN THE FORECAST STORM MOTION BY THE GFS/NAM/RAP. OF BIGGEST CONCERN LATER TODAY IS THIS STORM MOTION AND AVAILABLE MOISTURE. NAM/GFS BOTH SHOWING PW VALUES AROUND 2" OVER SOUTH- CENTRAL ZONES...WITH A SLOW STORM MOTION ONLY AROUND 5 KNOTS. THIS IS CONCERNING FOR HEAVY RAIN POTENTIAL...ESPECIALLY GIVEN THAT PORTIONS OF POLK/HIGHLANDS COUNTIES ALREADY RECEIVED SIGNIFICANT RAINFALL THIS WEEK. WILL NEED TO MONITOR STORMS CLOSELY FOR LOCALIZED FLOODING POTENTIAL. LOCAL HIRES GUIDANCE HAVE ALSO BEEN SHOWING FOR SEVERAL RUNS FAIRLY IMPRESSIVE UPDRAFT VELOCITIES WITH THE ACTIVITY LATER TODAY...ON THE ORDER OF 15 M/S. THESE ARE DECENT VALUES FOR SEA-BREEZE STORMS...ESPECIALLY THIS TIME OF YEAR. GIVEN THE AVAILABLE MOISTURE AND POTENTIAL FOR POTENT UPDRAFTS...PRECIP LOADING AND DOWNDRAFT WIND GUST THREAT WITH THE STRONGER STORMS WILL ALSO NEED TO BE MONITORED CLOSELY. CONVECTION IS LIKELY TO LINGER WELL INTO THE LATE EVENING HOURS OVER OUR SOUTH-CENTRAL ZONES GIVEN THE NEARBY FRONTAL FOCUS...BUT SHOULD BE ENDING EARLIER OVER THE REST OF THE FORECAST AREA. THE SECOND HALF OF THE NIGHT APPEARS MUCH QUIETER...AS WOULD BE EXPECTED WITH THE LOSS OF DIURNAL HEATING. ONE IMPULSE AFTER ANOTHER WILL BE MOVING ALONG THE NORTHERN GULF COAST...AND ANY OF THESE MAY THREATEN OUR FAR NORTHERN NATURE COAST ZONES (LEVY/CITRUS) WITH A ROUND OF SHOWER. CURRENTLY THE GUIDANCE SEEMS TO GRABBING ONTO ANOTHER ONE OF THESE ROUNDS LATE TONIGHT. THE IMPULSES ARE SO SUBTLE AND DEPENDENT ON JUST THE RIGHT DOWNSTREAM CONVECTIVE ACTIVITY...THAT FEEL GOING TO AGGRESSIVE WITH POPS AT THIS POINT IS UNNECESSARY. WILL LET THE DAYSHIFT REEVALUATE FOR THESE NORTHERN ZONES AFTER 06Z. FRIDAY... BOUNDARY BEGINS TO DECAY...WITH A WEAK GRADIENT ALLOWING FOR A MORE UNIFORM SEA-BREEZE TO DEVELOP ALONG THE FL WEST COAST. 1000-700MB FLOW FROM THE W/NW WOULD SUGGEST THIS SEABREEZE MOVE INLAND MORE QUICKLY...WITH EAST/WEST COAST SEA-BREEZE INTERACTIONS OCCURRING OVER OUR FAR INLAND ZONES OR EVEN OVER TOWARD THE I-95 CORRIDOR. WITH THIS IN MIND...OVERALL RAIN CHANCES APPEAR LOWER FOR THE I-75 CORRIDOR...ESPECIALLY THIS CORRIDOR SOUTH OF THE TAMPA BAY AREA. HIGHEST POPS 50-60% WILL THEREFORE EXIST WELL INLAND OVER SOUTHERN AREAS...AND ALSO ACROSS THE NATURE COAST IN CLOSER PROXIMITY TO ANY PASSING SYNOPTIC SUPPORT. && .LONG TERM (SATURDAY THROUGH NEXT WEDNESDAY)... THE PERIOD BEGINS WITH AN UPPER LEVEL CUT-OFF LOW NEAR THE FOUR CORNERS REGION AND RIDGING FROM THE GULF OF MEXICO TO NEAR THE GREAT LAKES. A FRONTAL BOUNDARY STRETCHES ALONG THE EASTERN GULF COAST AND THROUGH NORTHERN FL WHILE MID-ATLANTIC HIGH PRESSURE RIDGES SOUTH INTO FL WITH A WEAK GRADIENT. THROUGH THE WEEKEND THE CUT-OFF LOW TRACKS UP TO THE GREAT LAKES...WITH A SURFACE LOW FORMING AND TRAILING A COLD FRONT THAT ARCS THROUGH THE SOUTHEAST U.S. AND INTO THE GULF...AND OPENS INTO A BROAD TROUGH DOWN INTO THE GULF. THE UPPER RIDGE SLIDES OFF THE EASTERN SEABOARD WHILE THE FRONTAL BOUNDARY LIFTS NORTHWARD. A MOIST AIRMASS REMAINS IN PLACE AS THE FRONTAL BOUNDARY DEPARTS AND LOW LEVEL FLOW SHIFTS FROM EASTERLY TO SOUTHERLY...BUT WITH AFTERNOON SEAS BREEZES..AND INCREASE IN STRENGTH AS THE COLD FRONT MOVES INTO THE GULF. THIS WILL RESULT IN SHOWERS AND THUNDERSTORMS WITH THE BEST COVERAGE IN THE AFTERNOONS...IN THE CHANCE RANGE. FOR MON-WED THE UPPER LEVEL TROUGH SLOWLY SHIFTS EAST...DOMINATING THE EASTERN U.S. WHILE THE SURFACE LOW EJECTS INTO CANADA AND DRAGS THE COLD FRONT OUT OVER THE ATLANTIC...BUT WITH THE SOUTHERN END SLOWLY SAGGING SOUTHWARD ACROSS FL. SOUTHERLY AND SOUTHWESTERLY FLOW WILL INCREASE EARLY IN THE PERIOD PROVIDING ADDITIONAL MOISTURE WHICH WITH THE APPROACHING FRONT WILL RESULT IN SHOWERS AND THUNDERSTORMS..WITH CHANCE TO LIKELY POPS MON AS THE FRONT PUSHES INTO THE AREA. RAIN CHANCES BEGINS TO TREND DOWN TUE-WED AS THE FRONT SLIDES SOUTH AND WEAKENS. TEMPERATURES START OFF WELL ABOVE NORMAL BUT GRADUALLY DROP BY MID WEEK. HIGHS DECREASE TO NEAR NORMAL BUT THE OVERNIGHT LOWS WILL CONTINUE ON THE WARM SIDE. && .AVIATION... VFR CONDITIONS PREVAILING ACROSS WEST-CENTRAL AND MOST OF SOUTHWEST FLORIDA EARLY THIS MORNING. HAVE SEEN A FEW SHOWERS AROUND KFMY/KRSW WITH BRIEF MVFR CIGS...HOWEVER THIS ACTIVITY SHOULD DIMINISH BEFORE SUNRISE. AVIATION CONCERNS TODAY WILL CENTER AROUND THE DEVELOPMENT OF SCT TO NMRS SHOWERS AND THUNDERSTORMS FOR THE AFTERNOON/EVENING HOURS. THE GREATEST COVERAGE OF STORMS WILL BE INLAND FROM THE I-75 CORRIDOR AFTER 17Z...ALTHOUGH EVEN TERMINALS ALONG I-75 WILL HAVE THE POTENTIAL FOR A STORM. && .MARINE... A WEAK FRONTAL BOUNDARY WILL DIP SOUTH INTO NORTHERN FLORIDA AND THE FAR NORTHEAST GULF OF MEXICO TODAY AND REMAIN IN PLACE THROUGH FRIDAY. THIS BOUNDARY WILL THEN DECAY FRIDAY NIGHT INTO SATURDAY AS WEAK HIGH PRESSURE BUILDS SOUTH INTO THE REGION FROM THE NORTH. WINDS AND SEAS WILL REMAIN LOW THROUGH SATURDAY WITH SPEEDS GENERALLY LESS THAN 10-15 KNOTS. THE BEST POTENTIAL FOR DEFINED SEA-BREEZE DEVELOPMENT NEAR THE COAST THE NEXT TWO DAYS WILL BE TO THE SOUTH OF THE FRONTAL BOUNDARY...MAINLY SOUTH OF TARPON SPRINGS. && .FIRE WEATHER... A WEAK FRONT WILL DIP INTO NORTHERN FLORIDA TODAY AND THEN REMAIN NEARLY STATIONARY THROUGH FRIDAY. NO SIGNIFICANT FIRE WEATHER CONCERNS ARE EXPECTED THROUGH THE END OF THE WEEK. RELATIVE HUMIDITY VALUES WILL REMAIN WELL ABOVE CRITICAL LEVELS. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BECOME RATHER NUMEROUS OVER INTERIOR CENTRAL AND SOUTH-CENTRAL ZONES LATER THIS AFTERNOON AND EVENING WITH MORE SCATTERED VARIETY STORMS ELSEWHERE. SHOWERS AND STORMS SHOULD AGAIN BE MOST NUMEROUS WELL INLAND FROM THE COAST ON FRIDAY. && .PRELIMINARY POINT TEMPS/POPS... TPA 86 72 85 71 / 50 30 40 20 FMY 89 71 88 71 / 40 40 20 10 GIF 87 69 86 69 / 80 50 60 20 SRQ 83 71 83 70 / 30 20 30 20 BKV 86 67 85 66 / 60 40 50 20 SPG 86 74 84 73 / 40 20 30 20 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/AVIATION/FIRE WX...MROCZKA LONG TERM/DECISION SUPPORT SERVICES...RUDE
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1022 PM EDT FRI APR 17 2015 .SYNOPSIS... UNSETTLED AND WET WEATHER PATTERN WILL CONTINUE THROUGH THE WEEKEND INTO MONDAY. A COLD FRONT WILL MOVE ACROSS THE AREA ON MONDAY AND HIGH PRESSURE WILL BUILD OVER THE AREA TUESDAY AND WEDNESDAY BRINGING FAIR WEATHER. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... HIGH PRESSURE OVER THE MID-ATLANTIC STATES WITH WEAK LOW PRESSURE OFF THE SC COAST. AN LARGE AREA OF MAINLY LIGHT RAIN EXTENDS FROM SOUTHERN GA TO CENTRAL SC. EXPECT THE WEAK LOW LEVEL WEDGE TO REMAIN OVERNIGHT AIDED BY THE ADDITIONAL RAINFALL ANTICIPATED. MAIN ISSUE IS PRECIPITATION POTENTIAL. APPEARANCE OF SIGNIFICANT UPPER SHORT WAVE...CURRENTLY SEEN ON SATELLITE WATER VAPOR IMAGERY OVER AL. THIS FEATURE WILL TRACK SLOWLY TO THE EAST OVERNIGHT. GIVEN THE LATEST HRRR GUIDANCE...WILL KEEP LIKELY OR GREATER POPS OVER THE WESTERN AND CENTRAL COUNTIES UNTIL AROUND 06Z...WITH CHANCE POPS ELSEWHERE. AFTER 06Z...MAINLY CHANCE POPS ACROSS THE AREA. LOW CONFIDENCE ON EXTENT OF FOG DUE TO PRECIP CHANCES AND CONSIDERABLE CLOUDINESS. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/... LATEST MODEL RUNS BRING A CHANGE TO THE FORECAST. IT APPEARS THAT AN UPPER IMPULSE WILL MOVE ACROSS THE AREA TONIGHT AND THIS WILL BRING AN ENHANCED CHANCE OF SHOWERS THAT WILL LINGER INTO SATURDAY. HIGH PRESSURE WILL NOSE SOUTH OVER THE AREA WITH WHAT LOOKS LIKE A CONTINUATION OF THE WEDGE. MODELS KEEP LOW LEVEL RH HIGH SO EXPECT MOSTLY CLOUDY ON SATURDAY. WILL KEEP POPS IN THE MORNING IN THE 30 TO 50 PERCENT RANGE AND AROUND 30 PERCENT IN THE AFTERNOON INTO THE EVENING. LATEST GUIDANCE IS SIGNIFICANTLY COOLER WITH SATURDAY MAX TEMPS AND HAVE LOWERED THE FORECAST INTO LOWER TO MID 70S. MODELS ARE AND FASTER MOVING THE NEXT SYSTEM INTO THE AREA ON SATURDAY NIGHT AND CONTINUING INTO SUNDAY AS LARGE UPPER LOW OVER THE WESTERN US OPENS AND MOVES EAST. EXPECT WIDESPREAD RAIN...AND POSSIBLY SOME EMBEDDED THUNDERSTORMS FROM LATE SATURDAY NIGHT THROUGH MOST OF SUNDAY. HAVE MAX TEMPS UPPER 60S NORTH TO UPPER 70S SOUTH. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... DEEP MOISTURE AND ISENTROPIC LIFT MOVE NORTHEAST OF THE AREA ON SUNDAY NIGHT BUT APPROACHING COLD FRONT AND UPPER LEVEL WAVE WILL KEEP THE CHANCE OF RAIN THROUGH MONDAY. EXPECT POSSIBLY A LINE OF CONVECTION WITH THE COLD FRONT ON MONDAY. HIGH PRESSURE BUILDS OVER THE REGION TUESDAY AND WEDNESDAY BRINGING A REPRIEVE FROM THE UNSETTLED PATTERN. UPPER FLOW BECOMES ZONAL FOR THE SECOND HALF OF THE WEEK WHICH IS AN MORE UNCERTAIN WEATHER PATTERN. THERE ARE SOME INDICATIONS OF LOW LEVEL MOISTURE RETURNING ON THURSDAY AND FRIDAY BUT GIVEN AN UNCERTAIN ZONAL PATTERN ALONG WITH BEING SEVERAL DAYS OUT WILL KEEP THE POPS LOW FOR NOW. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... WEDGE CONDITIONS APPEAR TO HAVE WEAKENED AT LEAST TEMPORARILY AS CIGS HAVE BECOME VFR AT ALL TERMINALS AS SOME LIGHT RAIN MOVES THROUGH THE REGION ASSOCIATED WITH AN UPPER DISTURBANCE CROSSING AL/GA. MODEL GUIDANCE AND TIME HEIGHT FORECASTS AND HI RES MODEL DATA INDICATING THAT THIS PERIOD OF VFR CIGS WILL BE SHORT LIVED AND CIGS WILL FALL BACK DOWN TO IFR BY 04Z ALL TERMINALS WITH THE LOSS OF HEATING AND LIGHT RAIN FALLING. LIGHT RAIN EXPECTED TO LINGER THROUGH THE NIGHT UNTIL THE SHORTWAVE PASSES AND EXPECT CIGS TO FALL INTO LIFR DURING THE PREDAWN HOURS AFTER 08Z-09Z. VSBYS ARE MORE DIFFICULT AND HAVE LOWER CONFIDENCE IN THAT FORECAST. GRADUAL IMPROVEMENT EXPECTED ON SATURDAY WITH A BRIEF PERIOD OF DRY WEATHER EXPECTED BEFORE YET ANOTHER ROUND OF PRECIPITATION BY SUNDAY. .EXTENDED AVIATION OUTLOOK... EXPECT INCREASING RAIN CHANCES...AND ASSOCIATED RESTRICTIONS...SATURDAY NIGHT...SUNDAY INTO SUNDAY NIGHT. THUNDER AND HEAVY RAIN WILL BE POSSIBLE SUNDAY/SUN NT. SCATTERED THUNDERSTORMS POSSIBLE MONDAY AFTERNOON AND EVENING. NO IMPACTS TO AVIATION EXPECTED MONDAY NIGHT THROUGH WEDNESDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
259 PM CDT THU APR 16 2015 .UPDATE... 1113 AM CDT TEMPERATURE AND PRECIPITATION TRENDS APPEAR TO BE ON TRACK LATE THIS MORNING UNDER SIGNIFICANT CLOUD COVER WITH A FEW AREAS OF PATCHY DRIZZLE MAINLY SOUTH OF THE LAKE. LIGHT WINDS UNDER THE CLOUD DECK ARE NOT ASSISTING THE MIXING OUT OF LOW LEVEL MOISTURE...BUT RAP RH TRENDS AND RECENT SATELLITE LOOPS SUGGEST THE CLOUDS WILL BE SCATTERING OUT LATER THIS AFTERNOON WHICH WOULD ALLOW TEMPERATURES TO CLIMB RAPIDLY AS SEEN ACROSS NORTHWEST ILLINOIS AND EASTERN IOWA. FOR AREAS THAT DO NOT MANAGE TO CLEAR AS EARLY...HIGHS MAY NEED TO BE TWEAKED DOWNWARD A FEW DEGREES. LENNING && .SHORT TERM... 304 AM CDT THROUGH FRIDAY... COMPACT BUT STRONG VORT IS MOVING NORTHWARD ACROSS ILLINOIS THIS MORNING AND DRIVING AN AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS NORTHWARD ACROSS FAR EASTERN ILLINOIS AND WESTERN INDIANA EARLY THIS MORNING. THIS ACTIVITY WILL AFFECT CHICAGO AREA AND NW INDY INTO THE EARLY MORNING HOURS BEFORE MOVING OUT OF THE REGION. FAIRLY EXTENSIVE CLOUD COVER UPSTREAM AND WITH RAIN LIKELY TO FURTHER SATURATED THE COLUMN AM CONCERNED THAT CLOUD COVER COULD BE FAIRLY PREVALENT ACROSS ESPECIALLY EASTERN PORTIONS OF THE CWA INTO AT LEAST THE FIRST PART OF THE AFTERNOON WHICH SHOULD SLOW TEMPERATURE RISE AND LIKELY KEEP TEMPS FROM GETTING ABOVE GUIDANCE TODAY UNLIKE THE PAST COUPLE DAYS. IN THE WAKE OF THIS MORNING`S SHORTWAVE LOOK FOR HEIGHT RISES AS UPPER RIDGING BUILDS INTO THE REGION IN ADVANCE OF THE BIG WESTERN CUT-OFF LOW. RISING HEIGHTS AND WARMING LOW/MID LEVEL LOOK TO SET THE STAGE FOR A COUPLE OF RATHER TOASTY DAYS AWAY FROM THE LAKEFRONT. PROGGED 925MB TEMPS INTO THE MID TEENS CELSIUS SUPPORT HIGHS AROUND 80F AND HAVE BUMPED TEMPS IN THE GRIDS UPWARD TOWARD THE DIRECTION...AND GIVEN THE RECENT COOL BIAS IN GUIDANCE ITS POSSIBLE THAT THESE FORECAST GRIDS COULD END UP TOO COOL STILL WITH 80F+ ACROSS MOST OF THE CWA FRIDAY AND SATURDAY. IZZI && .LONG TERM... 304 AM CDT FRIDAY NIGHT THROUGH WEDNESDAY... GUIDANCE IS REMAINS IN RELATIVELY GOOD AGREEMENT ON THE EJECTION OF THE BIG WESTERN CLOSED LOW WITH SHOWERS AND THUNDERSTORMS IN ADVANCE OF THIS SYSTEM EXPECTED TO ARRIVE PROBABLY SUNDAY AND COULD STICK AROUND AT TIMES INTO SUNDAY NIGHT. GFS REMAINS IS ON THE FASTER END OF THE GUIDANCE ENVELOPE...BUT GIVEN THE TENDENCY FOR THESE SYSTEMS TO BE SLOWER THAN PROGGED HAVE KEPT POPS BELOW GUIDANCE SAT NIGHT MORE IN LINE WITH THE SLOWER GEM SOLUTION. THE WESTERN CUT OFF LOW IS PROGGED TO PHASE WITH AMPLIFYING NORTHERN STREAM LONG TROUGH THAT LOOKS TO STALL OUT OVER THE GREAT LAKES REGION NEXT WEEK. THIS WILL RESULT IN AN END TO THE ABOVE AVERAGE TEMPERATURES THAT HAVE DOMINATED MUCH OF THIS MONTH...BUT LOOKS TO BE A FAIRLY DRY PATTERN THROUGH THURSDAY. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * LIGHT AND VARIABLE WINDS FAVORING EAST AND NORTHEAST THROUGH THE AFTERNOON. MDB //DISCUSSION...UPDATED 18Z... MVFR LEVEL CLOUDS ARE QUICKLY ERODING LEAVING A VFR DECK OF AROUND 6000 FT. THIS DECK WILL MOVE DRIFT EAST AND PROBABLY ERODE A BIT THROUGH THE AFTERNOON WITH SOME STRATO CU DEVELOPING ON THE FRINGES...WHICH WOULD ALSO BE VFR. OTHERWISE LIGHT AND VARIABLE WINDS WILL BE THE RULE THROUGH THE AFTERNOON AND EVEN THE REST OF THE NIGHT. EXPECT THAT ORD/MDW WILL FAVOR AN EAST TO NORTHEAST DIRECTION THANKS TO LAKE INFLUENCES BUT STILL SEE QUITE A BIT OF VARIABILITY. GYY WOULD LIKELY BE NORTH TO NORTHEAST WITH VARIABILITY. MANY AREAS WILL PROBABLY EVEN GO CALM AT TIMES. THERE MAY BE SOME FOG THAT DEVELOPS TONIGHT BUT GIVEN THE DRY CONDITIONS OF THE PAST FEW DAYS AND ONLY SOME SPOTTY SHOWERS/DRIZZLE THIS MORNING THE POTENTIAL IS PRETTY LOW. MDB //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN WIND FORECAST. MDB //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...VFR. WX NIL. SOUTHEAST WINDS LESS THAN 10 KT. SATURDAY...VFR...THEN SLIGHT CHANCE SHRA/MVFR AFTER MIDNIGHT. EAST WINDS 10-15 KT. SUNDAY...LIKELY SHRA/CHANCE TSRA. MVFR POSSIBLE. EAST WINDS 10-15 KT...BECMG NORTHWEST LESS THAN 10 KT OVERNIGHT. MONDAY...CHANCE SHRA MONDAY...SLIGHT CHANCE SHRA OVERNIGHT. MVFR POSSIBLE. WEST TO NORTHWEST WINDS 10-15 KT. TUESDAY...SLIGHT CHANCE SHRA...OTRW VFR. WEST WINDS 15-20KT TUESDAY...DIMINISHING TO 5-10 KT OVERNIGHT. WEDNESDAY...SLIGHT CHANCE SHRA...OTRW VFR. WEST WINDS LESS THAN 10 KT. KREIN && .MARINE... 304 AM CDT A RELATIVELY QUIET PERIOD OF WEATHER IS EXPECTED FOR LAKE MICHIGAN FOR THE NEXT SEVERAL DAYS. HIGH PRESSURE CENTERED OVER SOUTHERN QUEBEC WILL MOVE OFF THE NEW ENGLAND COAST TODAY...AS LOW PRESSURE OVER NORTHERN ONTARIO MOVES ACROSS JAMES BAY. MEANWHILE...LOW PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY DRIFT SOUTHEAST. WITH A WEAK PRESSURE GRADIENT OVER THE LAKE...LIGHT WINDS WILL COVER THE OPEN WATERS WHILE ONSHORE FLOW AND A LAKE BREEZE DEVELOP OVER THE NEARSHORE WATERS TODAY. A SIMILARLY SETUP IS EXPECTED FOR FRIDAY...BUT THEN A DEEPENING LOW WILL PASS TO THE NORTH OF LAKE SUPERIOR FRIDAY EVENING WITH AN ASSOCIATED COLD FRONT PUSHING SOUTH DOWN LAKE MICHIGAN FRIDAY NIGHT...ALLOWING FOR STRENGTHENING NORTH TO NORTHEAST WINDS TO DEVELOP OVER THE LAKE FOLLOWING THE FROPA...BUT DO NOT EXPECT WINDS TO EXCEED 20-25 KT. HIGH PRESSURE WILL THEN BUILD SOUTHEAST ACROSS THE GREAT LAKES AND ONTARIO FRIDAY NIGHT INTO SATURDAY. && .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
1210 PM CDT THU APR 16 2015 .UPDATE... 1113 AM CDT TEMPERATURE AND PRECIPITATION TRENDS APPEAR TO BE ON TRACK LATE THIS MORNING UNDER SIGNIFICANT CLOUD COVER WITH A FEW AREAS OF PATCHY DRIZZLE MAINLY SOUTH OF THE LAKE. LIGHT WINDS UNDER THE CLOUD DECK ARE NOT ASSISTING THE MIXING OUT OF LOW LEVEL MOISTURE...BUT RAP RH TRENDS AND RECENT SATELLITE LOOPS SUGGEST THE CLOUDS WILL BE SCATTERING OUT LATER THIS AFTERNOON WHICH WOULD ALLOW TEMPERATURES TO CLIMB RAPIDLY AS SEEN ACROSS NORTHWEST ILLINOIS AND EASTERN IOWA. FOR AREAS THAT DO NOT MANAGE TO CLEAR AS EARLY...HIGHS MAY NEED TO BE TWEAKED DOWNWARD A FEW DEGREES. LENNING && .SHORT TERM... 304 AM CDT THROUGH FRIDAY... COMPACT BUT STRONG VORT IS MOVING NORTHWARD ACROSS ILLINOIS THIS MORNING AND DRIVING AN AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS NORTHWARD ACROSS FAR EASTERN ILLINOIS AND WESTERN INDIANA EARLY THIS MORNING. THIS ACTIVITY WILL AFFECT CHICAGO AREA AND NW INDY INTO THE EARLY MORNING HOURS BEFORE MOVING OUT OF THE REGION. FAIRLY EXTENSIVE CLOUD COVER UPSTREAM AND WITH RAIN LIKELY TO FURTHER SATURATED THE COLUMN AM CONCERNED THAT CLOUD COVER COULD BE FAIRLY PREVALENT ACROSS ESPECIALLY EASTERN PORTIONS OF THE CWA INTO AT LEAST THE FIRST PART OF THE AFTERNOON WHICH SHOULD SLOW TEMPERATURE RISE AND LIKELY KEEP TEMPS FROM GETTING ABOVE GUIDANCE TODAY UNLIKE THE PAST COUPLE DAYS. IN THE WAKE OF THIS MORNING`S SHORTWAVE LOOK FOR HEIGHT RISES AS UPPER RIDGING BUILDS INTO THE REGION IN ADVANCE OF THE BIG WESTERN CUT-OFF LOW. RISING HEIGHTS AND WARMING LOW/MID LEVEL LOOK TO SET THE STAGE FOR A COUPLE OF RATHER TOASTY DAYS AWAY FROM THE LAKEFRONT. PROGGED 925MB TEMPS INTO THE MID TEENS CELSIUS SUPPORT HIGHS AROUND 80F AND HAVE BUMPED TEMPS IN THE GRIDS UPWARD TOWARD THE DIRECTION...AND GIVEN THE RECENT COOL BIAS IN GUIDANCE ITS POSSIBLE THAT THESE FORECAST GRIDS COULD END UP TOO COOL STILL WITH 80F+ ACROSS MOST OF THE CWA FRIDAY AND SATURDAY. IZZI && .LONG TERM... 304 AM CDT FRIDAY NIGHT THROUGH WEDNESDAY... GUIDANCE IS REMAINS IN RELATIVELY GOOD AGREEMENT ON THE EJECTION OF THE BIG WESTERN CLOSED LOW WITH SHOWERS AND THUNDERSTORMS IN ADVANCE OF THIS SYSTEM EXPECTED TO ARRIVE PROBABLY SUNDAY AND COULD STICK AROUND AT TIMES INTO SUNDAY NIGHT. GFS REMAINS IS ON THE FASTER END OF THE GUIDANCE ENVELOPE...BUT GIVEN THE TENDENCY FOR THESE SYSTEMS TO BE SLOWER THAN PROGGED HAVE KEPT POPS BELOW GUIDANCE SAT NIGHT MORE IN LINE WITH THE SLOWER GEM SOLUTION. THE WESTERN CUT OFF LOW IS PROGGED TO PHASE WITH AMPLIFYING NORTHERN STREAM LONG TROUGH THAT LOOKS TO STALL OUT OVER THE GREAT LAKES REGION NEXT WEEK. THIS WILL RESULT IN AN END TO THE ABOVE AVERAGE TEMPERATURES THAT HAVE DOMINATED MUCH OF THIS MONTH...BUT LOOKS TO BE A FAIRLY DRY PATTERN THROUGH THURSDAY. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * LIGHT AND VARIABLE WINDS FAVORING EAST AND NORTHEAST THROUGH THE AFTERNOON. MDB //DISCUSSION...UPDATED 18Z... MVFR LEVEL CLOUDS ARE QUICKLY ERODING LEAVING A VFR DECK OF AROUND 6000 FT. THIS DECK WILL MOVE DRIFT EAST AND PROBABLY ERODE A BIT THROUGH THE AFTERNOON WITH SOME STRATO CU DEVELOPING ON THE FRINGES...WHICH WOULD ALSO BE VFR. OTHERWISE LIGHT AND VARIABLE WINDS WILL BE THE RULE THROUGH THE AFTERNOON AND EVEN THE REST OF THE NIGHT. EXPECT THAT ORD/MDW WILL FAVOR AN EAST TO NORTHEAST DIRECTION THANKS TO LAKE INFLUENCES BUT STILL SEE QUITE A BIT OF VARIABILITY. GYY WOULD LIKELY BE NORTH TO NORTHEAST WITH VARIABILITY. MANY AREAS WILL PROBABLY EVEN GO CALM AT TIMES. THERE MAY BE SOME FOG THAT DEVELOPS TONIGHT BUT GIVEN THE DRY CONDITIONS OF THE PAST FEW DAYS AND ONLY SOME SPOTTY SHOWERS/DRIZZLE THIS MORNING THE POTENTIAL IS PRETTY LOW. MDB //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN WIND FORECAST. MDB //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...VFR. WX NIL. SOUTHEAST WINDS LESS THAN 10 KT. SATURDAY...VFR...THEN SLIGHT CHANCE SHRA/MVFR AFTER MIDNIGHT. EAST WINDS 10-15 KT. SUNDAY...LIKELY SHRA/CHANCE TSRA. MVFR POSSIBLE. EAST WINDS 10-15 KT...BECMG NORTHWEST LESS THAN 10 KT OVERNIGHT. MONDAY...CHANCE SHRA MONDAY...SLIGHT CHANCE SHRA OVERNIGHT. MVFR POSSIBLE. WEST TO NORTHWEST WINDS 10-15 KT. TUESDAY...SLIGHT CHANCE SHRA...OTRW VFR. WEST WINDS 15-20KT TUESDAY...DIMINISHING TO 5-10 KT OVERNIGHT. WEDNESDAY...SLIGHT CHANCE SHRA...OTRW VFR. WEST WINDS LESS THAN 10 KT. KREIN && .MARINE... 304 AM CDT A RELATIVELY QUIET PERIOD OF WEATHER IS EXPECTED FOR LAKE MICHIGAN FOR THE NEXT SEVERAL DAYS. HIGH PRESSURE CENTERED OVER SOUTHERN QUEBEC WILL MOVE OFF THE NEW ENGLAND COAST TODAY...AS LOW PRESSURE OVER NORTHERN ONTARIO MOVES ACROSS JAMES BAY. MEANWHILE...LOW PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY DRIFT SOUTHEAST. WITH A WEAK PRESSURE GRADIENT OVER THE LAKE...LIGHT WINDS WILL COVER THE OPEN WATERS WHILE ONSHORE FLOW AND A LAKE BREEZE DEVELOP OVER THE NEARSHORE WATERS TODAY. A SIMILARLY SETUP IS EXPECTED FOR FRIDAY...BUT THEN A DEEPENING LOW WILL PASS TO THE NORTH OF LAKE SUPERIOR FRIDAY EVENING WITH AN ASSOCIATED COLD FRONT PUSHING SOUTH DOWN LAKE MICHIGAN FRIDAY NIGHT...ALLOWING FOR STRENGTHENING NORTH TO NORTHEAST WINDS TO DEVELOP OVER THE LAKE FOLLOWING THE FROPA...BUT DO NOT EXPECT WINDS TO EXCEED 20-25 KT. HIGH PRESSURE WILL THEN BUILD SOUTHEAST ACROSS THE GREAT LAKES AND ONTARIO FRIDAY NIGHT INTO SATURDAY. && .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
1126 AM CDT THU APR 16 2015 .UPDATE... 1113 AM CDT TEMPERATURE AND PRECIPITATION TRENDS APPEAR TO BE ON TRACK LATE THIS MORNING UNDER SIGNIFICANT CLOUD COVER WITH A FEW AREAS OF PATCHY DRIZZLE MAINLY SOUTH OF THE LAKE. LIGHT WINDS UNDER THE CLOUD DECK ARE NOT ASSISTING THE MIXING OUT OF LOW LEVEL MOISTURE...BUT RAP RH TRENDS AND RECENT SATELLITE LOOPS SUGGEST THE CLOUDS WILL BE SCATTERING OUT LATER THIS AFTERNOON WHICH WOULD ALLOW TEMPERATURES TO CLIMB RAPIDLY AS SEEN ACROSS NORTHWEST ILLINOIS AND EASTERN IOWA. FOR AREAS THAT DO NOT MANAGE TO CLEAR AS EARLY...HIGHS MAY NEED TO BE TWEAKED DOWNWARD A FEW DEGREES. LENNING && .SHORT TERM... 304 AM CDT THROUGH FRIDAY... COMPACT BUT STRONG VORT IS MOVING NORTHWARD ACROSS ILLINOIS THIS MORNING AND DRIVING AN AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS NORTHWARD ACROSS FAR EASTERN ILLINOIS AND WESTERN INDIANA EARLY THIS MORNING. THIS ACTIVITY WILL AFFECT CHICAGO AREA AND NW INDY INTO THE EARLY MORNING HOURS BEFORE MOVING OUT OF THE REGION. FAIRLY EXTENSIVE CLOUD COVER UPSTREAM AND WITH RAIN LIKELY TO FURTHER SATURATED THE COLUMN AM CONCERNED THAT CLOUD COVER COULD BE FAIRLY PREVALENT ACROSS ESPECIALLY EASTERN PORTIONS OF THE CWA INTO AT LEAST THE FIRST PART OF THE AFTERNOON WHICH SHOULD SLOW TEMPERATURE RISE AND LIKELY KEEP TEMPS FROM GETTING ABOVE GUIDANCE TODAY UNLIKE THE PAST COUPLE DAYS. IN THE WAKE OF THIS MORNING`S SHORTWAVE LOOK FOR HEIGHT RISES AS UPPER RIDGING BUILDS INTO THE REGION IN ADVANCE OF THE BIG WESTERN CUT-OFF LOW. RISING HEIGHTS AND WARMING LOW/MID LEVEL LOOK TO SET THE STAGE FOR A COUPLE OF RATHER TOASTY DAYS AWAY FROM THE LAKEFRONT. PROGGED 925MB TEMPS INTO THE MID TEENS CELSIUS SUPPORT HIGHS AROUND 80F AND HAVE BUMPED TEMPS IN THE GRIDS UPWARD TOWARD THE DIRECTION...AND GIVEN THE RECENT COOL BIAS IN GUIDANCE ITS POSSIBLE THAT THESE FORECAST GRIDS COULD END UP TOO COOL STILL WITH 80F+ ACROSS MOST OF THE CWA FRIDAY AND SATURDAY. IZZI && .LONG TERM... 304 AM CDT FRIDAY NIGHT THROUGH WEDNESDAY... GUIDANCE IS REMAINS IN RELATIVELY GOOD AGREEMENT ON THE EJECTION OF THE BIG WESTERN CLOSED LOW WITH SHOWERS AND THUNDERSTORMS IN ADVANCE OF THIS SYSTEM EXPECTED TO ARRIVE PROBABLY SUNDAY AND COULD STICK AROUND AT TIMES INTO SUNDAY NIGHT. GFS REMAINS IS ON THE FASTER END OF THE GUIDANCE ENVELOPE...BUT GIVEN THE TENDENCY FOR THESE SYSTEMS TO BE SLOWER THAN PROGGED HAVE KEPT POPS BELOW GUIDANCE SAT NIGHT MORE IN LINE WITH THE SLOWER GEM SOLUTION. THE WESTERN CUT OFF LOW IS PROGGED TO PHASE WITH AMPLIFYING NORTHERN STREAM LONG TROUGH THAT LOOKS TO STALL OUT OVER THE GREAT LAKES REGION NEXT WEEK. THIS WILL RESULT IN AN END TO THE ABOVE AVERAGE TEMPERATURES THAT HAVE DOMINATED MUCH OF THIS MONTH...BUT LOOKS TO BE A FAIRLY DRY PATTERN THROUGH THURSDAY. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * LIGHT NORTHEAST WINDS WHICH WILL BE VARIABLE AT TIMES. * MVFR CIGS IMPROVING TO VFR MID/LATE AFTERNOON. MDB //DISCUSSION...UPDATED 16Z... IFR HAS IMPROVED TO MVFR EXCEPT FOR AREAS SOUTH OF THE TERMINALS. AM STILL THINKING THAT ORD/MDW MAY SEE LOWERING OF CIGS TOWARDS 015 IN THE NEXT 1-2 HRS BEFORE LIFTING AND EVENTUALLY SCATTERING OCCURS. WINDS HAVE DROPPED OFF AND THE DIRECTION HAS BECOME QUITE VARIABLE ACROSS THE TERMINALS BUT EXPECT THE LAKE INFLUENCE TO PROVIDE A SOMEWHAT STEADIER EAST TO NORTHEAST DIRECTION AT ORD/MDW AND NORTH TO NORTHEAST DIRECTION AT GYY LATER THIS AFTERNOON. MAY ALSO SEE A SLIGHT BUMP IN SPEEDS AS THIS OCCURS. MDB FROM 12Z... A WEAK MID LEVEL CIRCULATION MOVING NWD ALONG THE IL/IN BORDER. SCT SHOWERS ASSOCIATED WITH THE MID LEVEL CIRCULATION HAVE MOVED INTO FAR NERN IL AND NWRN IN...MAINLY IMPACTING GYY/ORD/MDW. THE POTENTIAL FOR ANY PCPN REACHING THE GROUND AT DPA IS DIMINISHING AS THE MID LEVEL CIRCULATION SHOULD TAKE A TURN TO THE NORTHEAST LATER THIS MORNING. WITH THE ARRIVAL OF SHOWERS OVER THE EASTERN TERMINALS...FORECAST SOUNDINGS INDICATE A PERIOD OF MVFR...AND POSSIBLY IFR CIGS THROUGH LATE THIS MORNING. LIGHT WINDS BY THAT TIME SUGGEST MVFR CIGS MAY BE A LITTLE SLOW TO LIFT/SCATTER...AND POSSIBLE MAY NOT IMPROVE TO VFR UNTIL THIS AFTERNOON. THERE IS ALSO A CHANCE FOR SOME THUNDERSTORMS INVOF THE CIRCULATION CENTER...BUT IT IS UNLIKELY THAT ANY THUNDER WILL IMPACT THE TERMINALS...AND SHOULD REMAIN TO THE SOUTHEAST. WITH A WEAK GRADIENT IN PLACE...WINDS ARE EXPECTED TO BECOME NORTHEAST NEAR LAKE MICHIGAN...WHILE THE MORE INLAND SITES DPA AND RFD ARE LIKELY SEE LIGHT NORTH-NORTHWEST WINDS THIS AFTERNOON. KREIN //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE IN IN MVFR CIGS PERSISTING THROUGH EARLY AFTERNOON WITH MEDIUM CONFIDENCE IN TIMING OF SCATTERING. * HIGH CONFIDENCE IN LIGHT WIND SPEEDS AND VARIABLE WIND DIRECTION. MEDIUM-HIGH CONFIDENCE IT WILL FAVOR A NORTHEAST TO EAST DIRECTION. MDB //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...VFR. WX NIL. SOUTHEAST WINDS LESS THAN 10 KT. SATURDAY...VFR...THEN SLIGHT CHANCE SHRA/MVFR AFTER MIDNIGHT. EAST WINDS 10-15 KT. SUNDAY...LIKELY SHRA/CHANCE TSRA. MVFR POSSIBLE. EAST WINDS 10-15 KT...BECMG NORTHWEST LESS THAN 10 KT OVERNIGHT. MONDAY...CHANCE SHRA MONDAY...SLIGHT CHANCE SHRA OVERNIGHT. MVFR POSSIBLE. WEST TO NORTHWEST WINDS 10-15 KT. TUESDAY...SLIGHT CHANCE SHRA...OTRW VFR. WEST WINDS 15-20KT TUESDAY...DIMINISHING TO 5-10 KT OVERNIGHT. WEDNESDAY...SLIGHT CHANCE SHRA...OTRW VFR. WEST WINDS LESS THAN 10 KT. KREIN && .MARINE... 304 AM CDT A RELATIVELY QUIET PERIOD OF WEATHER IS EXPECTED FOR LAKE MICHIGAN FOR THE NEXT SEVERAL DAYS. HIGH PRESSURE CENTERED OVER SOUTHERN QUEBEC WILL MOVE OFF THE NEW ENGLAND COAST TODAY...AS LOW PRESSURE OVER NORTHERN ONTARIO MOVES ACROSS JAMES BAY. MEANWHILE...LOW PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY DRIFT SOUTHEAST. WITH A WEAK PRESSURE GRADIENT OVER THE LAKE...LIGHT WINDS WILL COVER THE OPEN WATERS WHILE ONSHORE FLOW AND A LAKE BREEZE DEVELOP OVER THE NEARSHORE WATERS TODAY. A SIMILARLY SETUP IS EXPECTED FOR FRIDAY...BUT THEN A DEEPENING LOW WILL PASS TO THE NORTH OF LAKE SUPERIOR FRIDAY EVENING WITH AN ASSOCIATED COLD FRONT PUSHING SOUTH DOWN LAKE MICHIGAN FRIDAY NIGHT...ALLOWING FOR STRENGTHENING NORTH TO NORTHEAST WINDS TO DEVELOP OVER THE LAKE FOLLOWING THE FROPA...BUT DO NOT EXPECT WINDS TO EXCEED 20-25 KT. HIGH PRESSURE WILL THEN BUILD SOUTHEAST ACROSS THE GREAT LAKES AND ONTARIO FRIDAY NIGHT INTO SATURDAY. && .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
1257 AM CDT THU APR 16 2015 .UPDATE... 758 PM CDT HAVE ONLY MADE SLIGHT ADJUSTMENTS TO THE REST OF TONIGHT FORECAST. A PICTURESQUE SKY OF VIRGA FROM CIRRUS/HIGH BASED ALTOCU OUT OUR WINDOW AT SUNDOWN AND SHARED WITH US BY SEVERAL OF OUR SOCIAL MEDIA FOLLOWERS. THE RAOB FROM DVN AT 00Z INDICATES A WARM ADVECTION PROFILE FROM JUST OFF THE DECK ALL THE WAY UP...WITH MOISTENING OCCURRING 15000 FT AND ABOVE ALONG WITH SOME MODEST LAPSE RATES...THOUGH VERY DRY STILL BELOW THAT. AT ILX THIS SATURATED LAYER IS DOWN TO 6000 FT WITH PRONOUNCED DRYING BELOW. WATER VAPOR IMAGERY INDICATES A COMPACT BUT MOISTURE-STARVED CIRCULATION IN SOUTHWEST ILLINOIS ADVANCING NORTHEAST...WITH SOME SHOWER ACTIVITY REACHING THE GROUND AHEAD OF IT IN THE CENTRALIA AND EFFINGHAM AREAS. TIMING THIS CORRIDOR OF FORCING WOULD MOVE IT INTO THE SOUTHERN FORECAST AREA AROUND 11 PM. RAP AND NAM FORECASTS INDICATE MOVE VEERED/SOUTHERLY PROFILES DOWN TO 900MB...WITH FORECAST MOISTURE TRANSPORT AND ADIABATIC LIFT LIKELY TO AID IN SATURATION FOR AT LEAST SCATTERED LIGHT SHOWERS ACROSS THE EASTERN FORECAST AREA. THAT IS IN LINE WITH GOING FORECAST AND FOR THE MOST PART CURRENT HIGH-RES GUIDANCE. JUST HAVE SLOWED THE START TIME OF POPS DOWN SLIGHTLY...BUT ALL IN ALL A NEGLIGIBLE CHANGE TO WORDING FOR MOST AREAS. RAINFALL AMOUNTS UNDER 0.15 OF AN INCH LOOK GOOD...WITH MOST OF NORTH CENTRAL ILLINOIS NOT SEEING MORE THAN A TRACE. GOING TEMPERATURES AND IMPROVING RELATIVE HUMIDITY VALUES LOOK ON TRACK. MTF && .SHORT TERM... 339 PM CDT THROUGH FRIDAY... BETTER AGREEMENT BETWEEN DETERMINISTIC MODELS AND THEIR ENSEMBLE COUNTERPARTS IS PROVIDING INCREASED FORECAST CONFIDENCE FOR THE REMAINDER OF THE WEEK AND INTO EARLY NEXT WEEK. THE PRIMARY UPPER LEVEL FEATURES BEING TRACKED INCLUDE A LARGE SOUTHERN STREAM LOW DIGGING INTO THE FOUR CORNERS...A DOWNSTREAM RIDGE WITH EMBEDDED SHORTWAVES...AND A CLOSED LOW PROJECTED TO DEVELOP IN A DEEPENING NORTHERN STREAM TROUGH AND MERGE LATE IN THE WEEKEND WITH THE SYSTEM THAT FINALLY WILL BE LIFTING OUT OF THE DESERT SOUTHWEST. AT LOWER LEVELS...MODELS AGREE IN LIFTING A WEAK SURFACE TROUGH ACROSS THE AREA TONIGHT AND IN TAKING A MORE DEVELOPED LOW PRESSURE SYSTEM ACROSS THE AREA SATURDAY NIGHT INTO SUNDAY IN CONJUNCTION WITH THE MERGING UPPER TROUGHS. FOR THIS EVENING AND OVERNIGHT...THE AREA OF SHOWERS AND ISOLATED TSRA STRETCHING FROM NORTHWEST IA ACROSS MO AND INTO KY IS CORRELATED WITH A GRADIENT OF ENHANCED MOISTURE FLUX DEPICTED IN THE RAP. AS THIS GRADIENT LIFTS NORTH...PRECIP CHANCES INCREASE TOWARD MIDNIGHT AND ESPECIALLY IN THE PREDAWN HOURS. FORECAST SOUNDINGS TREND TOWARD MOIST ADIABATIC AND DEEPLY SATURATED...SO PWATS INCREASE CONSIDERABLY OVERNIGHT BUT INSTABILITY IS TALL AND SKINNY. BETTER CHANCE OF TSRA WILL LIKELY REMAIN SOUTH AND EAST OF THE METRO AREA. DURING THE DAYTIME THURSDAY AND ESPECIALLY INTO THURSDAY NIGHT...HEIGHTS INCREASE ALOFT AS THE UPPER SHORTWAVES MOVE EAST OF THE AREA AND LOWER LEVELS DRY OUT. WILL CARRY LOW CHANCE POPS INTO THE THURSDAY MORNING HOURS AND EARLY AFTERNOON BUT KEEP THURSDAY NIGHT AND FRIDAY DRY. LENNING && .LONG TERM... 339 PM CDT FRIDAY NIGHT THROUGH WEDNESDAY... AFTER ANOTHER QUIET DAY ON SATURDAY...THE MERGING NORTHERN AND SOUTHERN STREAM TROUGHS AND DEVELOPMENT OF A CLOSED SURFACE LOW IN THE LEE OF THE ROCKIES WILL BRING INCREASED PRECIP CHANCES TO THE AREA FOR SATURDAY NIGHT AND SUNDAY. WITH THE CENTER OF THE SURFACE LOW PASSING SOUTH OF THE AREA ACROSS CENTRAL ILLINOIS...AM SEEING GOOD SUPPORT FOR SHOWERS SATURDAY NIGHT AND EARLY SUNDAY BUT NOT MUCH IN THE WAY OF CONVECTION UNTIL THE LOW PUSHES A WARM FRONT THROUGH THE AREA AROUND MIDDAY AND BRIEFLY MOVES THE AREA INTO THE WARM SECTOR AHEAD OF THE TRAILING COLD FRONT. THE PEAK PERIOD FOR TSRA WOULD APPEAR TO BE SUNDAY AFTERNOON AND EVENING. AFTER THE SURFACE LOW LIFTS WELL NORTH OF THE AREA SUNDAY NIGHT INTO MONDAY...CYCLONIC FLOW ALOFT AND RESIDUAL BOUNDARY LAYER MOISTURE MAY CONTINUE TO SUPPORT THE CHANCE OF SHOWERS INTO MONDAY...BUT A RIDGE OF HIGH PRESSURE WILL BEGIN TO BUILD FROM THE PLAINS INTO THE SOUTHERN GREAT LAKES BY TUESDAY...AGAIN DRYING THINGS OUT FOR AT LEAST THE FIRST HALF OF THE WEEK. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * EAST WINDS ARND 10 KT OVERNIGHT. * POTENTIAL FOR SHOWERS TONIGHT/EARLY THURSDAY MORNING. * A PERIOD OF MVFR/IFR LIKELY EARLY THURSDAY. * NORTHEAST WINDS 10 KT OR LESS THURSDAY. KREIN //DISCUSSION...UPDATED 06Z... THE EAST LOW LEVEL FLOW WAS MAINTAINING ADVECTION OF DRY LOW LEVEL AIR ACROSS MUCH OF NORTHERN ILLINOIS...WHILE SOUTH- SOUTHEAST WINDS ALOFT WERE PULLING MOISTURE NORTHWARD ALOFT OVER NORTHWESTERN INDIANA AS A WEAK MID LEVEL CIRCULATION MOVES NWD ALONG THE IL/IN BORDER. SCT SHOWERS ASSOCIATED WITH THE MID LEVEL CIRCULATION ARE SLOWLY MOVING NWD INTO NWRN IN...BUT ARE HAVING SOME TROUBLE OVERCOMING THE DRY LOW LEVEL AIR...SO IT WILL STILL TAKE SOME TIME FOR RAIN TO REACH THE SURFACE. STILL FEEL THAT THERE IS SOME POTENTIAL FOR SHRA AT THE CHICAGO AREA TERMINALS...ESPECIALLY GYY AND MDW...BUT ORD/DPA STILL HAVE SOME POTENTIAL AS WELL. WILL MAINTAIN THE VCSH AT RFD...THOUGH THE POTENTIAL FOR ANY PCPN REACHING THE GROUND THERE IS DIMINISHING AS THE MID LEVEL CIRCULATION SHOULD TAKE A TURN TO THE NORTHEAST LATE TONIGHT. WITH THE ARRIVAL OF SHOWERS OVER THE EASTERN TERMINALS...FORECAST SOUNDINGS INDICATE A PERIOD OF MVFR... AND POSSIBLY IFR CIGS EARLY THURSDAY MORNING. LIGHT WINDS BY THAT TIME SUGGEST MVFR CIGS MAY BE A LITTLE SLOW TO LIFT/SCATTER...AND MAY NOT IMPROVE TO VFR UNTIL THURSDAY AFTERNOON. WEAK GRADIENT AND LIGHT WINDS THURSDAY ARE EXPECTED TO BECOME NORTHEAST NEAR LAKE MICHIGAN...WHILE INLAND SITES DPA AND RFD ARE LIKELY SEE LIGHT NORTH-NORTHWEST WINDS. KREIN //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM CONFIDENCE IN SHRA COVERAGE/TIMING OVERNIGHT AND EARLY THURSDAY. * MEDIUM-HIGH CONFIDENCE IN PERIOD OF MVFR CIGS...MEDIUM IN IFR. * LOW-MEDIUM CONFIDENCE IN TRENDS THURSDAY. KREIN //OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z... FRIDAY...VFR. LIGHT VARIABLE WINDS BECOMING SOUTHEAST. SATURDAY...VFR. CHANCE OF SHRA WITH MVFR POSSIBLE SATURDAY NIGHT. NORTHEAST WINDS. SUNDAY...CHANCE SHRA. MVFR POSSIBLE. EAST-NORTHEAST WINDS. MONDAY...CHANCE SHRA EARLY. MVFR IMPROVING TO VFR. WEST-NORTHWEST WINDS. TUESDAY...VFR. CHANCE SHRA TUES NGT. WEST WINDS. RATZER && .MARINE... 153 PM CDT A RIDGE OF HIGH PRESSURE CENTERED JUST TO THE NORTHEAST OF THE GREAT LAKES IS ALLOWING FOR LIGHTER WINDS ACROSS THE LAKE TODAY...BUT WITH THE HIGHEST WINDS OF 10 TO 20 KT BEING OBSERVED OVER THE SOUTHERN HALF. EASTERLY WINDS OF 10 TO 20 KT WILL CONTINUE TONIGHT FOR THE SOUTH HALF AND THE NEARSHORE AS A TIGHTER PRESSURE GRADIENT REMAINS...AND WITH MORE STABLE CONDITIONS HELPING TO KEEP WIND SPEEDS DOWN. SURFACE PATTERN BEGINS TO RELAX LATER TONIGHT INTO THURSDAY MORNING WHILE SPEEDS DIMINISH AND WITH WINDS LIKELY BECOMING VARIABLE DURING THE DAY THURSDAY. THIS RELAXED PATTERN LOOKS TO PERSIST THROUGH THE END OF THE WORK WEEK...WITH GENERALLY LIGHTER SPEEDS IN PLACE. 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 DODGE CITY KS
635 PM CDT FRI APR 17 2015 ...UPDATED AVIATION DISCUSSION... .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 323 PM CDT FRI APR 17 2015 THE SHORT TERM FOCUS IS ON CONVECTION BOTH DURING THE AFTERNOON AND AGAIN LATER TONIGHT. A RELATIVELY WEAK TO MODERATE BOUYANCY/CAPE BUT HIGH SHEAR ENVIRONMENT IS SET UP FOR THIS AFTERNOON WITH A STATIONARY BOUNDARY SEPARATING A MOIST A COOLER AIRMASS ACROSS NORTHERN KANSAS AND DRYER WARMER AIR BEHIND A DRYLINE WEST OF LIBERAL. THE CONVECTIVE ALLOWING MODELS SUPPORT DISCREET THUNDERSTORM DEVELOPMENT IN THE UPSLOPE CONVERGENCE REGION WITH GENERALLY NORTHWARD RIGHT MOVING STORM MOTIONS. THIS WILL PRESENT A TORNADO RISK ACROSS OUR NORTHWEST COUNTIES ESPECIALLY THE AREA NORTHWEST OF THE GARDEN CITY TO SYRACUSE, DIGHTON AND SCOTT CITY. ADDITIONAL STORMS ARE LIKELY TO FORM FARTHER SOUTH AHEAD OF THE DRYLINE AND MOVE NORTHEAST THROUGH THE REST OF THE AREA, WITH STILL A THREAT OF HAIL AND WIND. A PERIOD OF SEVERE RISK THROUGH THE MID EVENING WILL FOLLOW AS FORCING FROM THE UPPER JET PROMOTES LIFT THROUGH THE REST OF OUR CENTRAL KANSAS COUNTIES. AS THE UPPER LOW OVERSPREADS THE AREA INTO SATURDAY MORNING, THE WARM/MOIST CONVEYOR BELT REGIONS WILL BE MOST LIKELY ACROSS THE NORTHERN AND EASTERN SECTIONS OF THE FORECAST AREA, BY CONSENSUS OF THE MODELS. HERE AN ADDITIONAL QUARTER TO LESS THAN AN INCH OF RAIN MAY OCCUR TROUGH SATURDAY MORNING. ADDITIONAL SEVERE STORMS ARE POSSIBLE SATURDAY UNDER THE UPPER COLD POOL AND VORTICITY MAXIMUM THAT BE MOVING INTO WESTERN KS. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 120 PM CDT FRI APR 17 2015 THE VERY SLOW MOVING UPPER LOW WILL CONTINUE TO PROVIDE CHANCES FOR PRECIPITATION UNTIL IT FINALLY CLEARS THE REGION...WHICH WILL NOT BE UNTIL SOMETIME SUNDAY. WE WILL BE KEEPING SOME CHANCE POPS ALONG/NORTH OF THE ARKANSAS RIVER AS THE 500-700MB DEFORMATION AXIS PIVOTS EASTWARD ACROSS WEST-CENTRAL KANSAS FROM LATE SATURDAY NIGHT THROUGH ABOUT MIDDAY SUNDAY. STRONG NORTH-NORTHWEST WINDS WILL FOLLOW ON SUNDAY AND AN OVERALL COOL, DAMP, WINDY DAY APPEARS QUITE LIKELY FOR MUCH OF THE DAY. WE WILL SEE SOME SCATTERING OUT OF CLOUDS BY LATE IN THE DAY SUNDAY FROM NORTHWEST TO SOUTHEAST, BUT IT WILL NOT LAST LONG AS ANOTHER MINOR SHORTWAVE TROUGH WILL BE SWINGING SOUTHEAST FROM THE NORTHERN ROCKIES AROUND A DEEPENING UPPER MIDWEST/GREAT LAKES LONGWAVE GYRE. THIS WILL ONLY ACT TO KEEP COOL TEMPERATURES AROUND MONDAY WITH A SLIGHT CHANCE FOR SOME LIGHT RAIN IN A WEAK NORTHWEST FLOW DEFORMATION AXIS. BY MID-WEEK, WE WILL SEE SOME WEAK RIDGING APPROACH THE HIGH PLAINS WITH WESTERN KANSAS IN THE MIDDLE OF A SPLIT-FLOW PATTERN. ACROSS THE WESTERN CONUS, THE CONTINUED AMPLIFICATION OF THE NORTHERN BRANCH WILL LEAD TO A MERGER OF NORTHERN BRANCH ENERGY WITH THE SOUTHERN BRANCH JET ACROSS THE DESERT SOUTHWEST REGION. MEANWHILE, THE AFOREMENTIONED GREAT LAKES LONGWAVE LOW WILL CONTINUE TO HAVE AN INFLUENCE WITH A COLD AIRMASS (FOR MID/LATE APRIL) LOCKED IN PLACE ACROSS THE NORTHERN PLAINS INTO THE MIDWEST REGION. A FAIRLY ROBUST LOWER TROPOSPHERIC BAROCLINIC ZONE WILL BECOME ESTABLISHED ACROSS THE CENTRAL PLAINS. THIS APPEARS TO BE A SETUP FAVORABLE FOR ORGANIZED (A) PRECIPITATION EVENT(S) AFFECTING SOUTHWEST KANSAS LATE IN THE UPCOMING WEEK. IT IS UNCLEAR HOW THIS WILL ALL UNFOLD AT DAYS 7-10 IN THE FORECAST, BUT THE LONGWAVE PATTERN CERTAINLY APPEARS FAVORABLE FOR A WETTER THAN AVERAGE 3-5 DAY PERIOD FOR MID TO LATE APRIL. THE OFFICIAL FORECAST WILL CONTINUE TO REFLECT 20-40 POPS FOR EACH PERIOD MID-LATE NEXT WEEK AS THIS WET PATTERN TAKES SHAPE ACROSS THE CENTRAL/SOUTHERN PLAINS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 633 PM CDT FRI APR 17 2015 LOW LEVEL MOISTURE INCREASES ACROSS WESTERN KANSAS OVERNIGHT AS A SOUTHEASTERLY FLOW CONTINUES. RAP AND HRR WERE BOTH IN DECENT AGREEMENT WITH MVRF CEILINGS DEVELOPING DEVELOPING TOWARDS 06Z, ESPECIALLY AT DDC. AREAS OF FOG WILL ALSO BE POSSIBLE IN THE DDC AND GCK AREA TOWARDS DAYBREAK AS CEILINGS LOWER INTO THE IFR CATEGORY AT TIMES. ON GOING CONVECTION WILL CONTINUE THROUGH EARLY TONIGHT NEAR AND NORTH OF A GCK TO DDC LINE. PRECIPITATION CHANCES ARE EXPECTED TO BRIEFLY INCREASE IN AREAL COVERAGE BETWEEN SUNSET AND 6Z SATURDAY AS AN UPPER LEVEL DISTURBANCE APPROACHES FROM THE WEST. && .PRELIMINARY POINT TEMPS/POPS... DDC 52 72 46 64 / 30 30 30 30 GCK 48 69 45 61 / 40 30 20 20 EHA 42 68 44 62 / 10 20 20 10 LBL 46 71 46 63 / 20 20 20 10 HYS 56 72 49 61 / 70 50 50 60 P28 56 75 51 66 / 80 50 60 40 && .DDC WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR KSZ084. && $$ SHORT TERM...RUSSELL LONG TERM...UMSCHEID AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS TOPEKA KS
630 PM CDT Fri Apr 17 2015 ...Update to aviation forecast discussion... .SHORT TERM...(This Evening through Saturday) Issued at 346 PM CDT FRI APR 17 2015 Upper low continues to spin over the Rockies this afternoon with an upper level jet rounding the base of the upper low and moving over New Mexico. Earlier showers and thunderstorms were moving out of the northern counties at 20Z. Some clearing was occurring across the southern and western sections of the cwa this afternoon. Latest meso analysis shows surface based CAPE around 500 to 1000 J/kg with an uncapped atmosphere. Expect scattered convection to develop in southwest Kansas along the dry line. additional scattered storms may develop in south west and south central Kansas per the latest runs of the RAP and HRRR. Models suggest additional development this evening across western and central Kansas moving northeast into north central Kansas with the increase and veering of the low level jet overnight. Models are in agreement with a lobe of energy working it`s way northeast out of Oklahoma later tonight and Saturday morning. May see a repeat of this morning with an area of showers and embedded thunderstorms moving across the area. Expect a break for a few hours in the afternoon, then chances increase again with storms developing again in the afternoon in western and central Kansas as upward vertical motion increases with the advance of the upper trough into the High Plains. Dryline looks to set up across western Kansas with the GFS the furthest east in central Kansas. Shear and instability will be favorable for some of the storms to be strong to severe with large hail and winds the main hazards in the late afternoon hours mainly west of a Herington to Washington line. .LONG TERM...(Saturday Night through Friday) Issued at 346 PM CDT FRI APR 17 2015 Short range models are relatively consistent in moving surface low and main piece of upper trough through eastern KS late Saturday night and Sunday. Ahead of this system Saturday night, increasing thunderstorm chances are expected, with some potential for severe weather, with the best chance in our forecast area over the western 2/3. Shear parameters are not very impressive and amount of sunshine and associated surface heating Sat afternoon and evening is also a little suspect so this is not a high probability thing. As the low and front move through on Sunday, some isolated thunder may continue in the east in the morning, but showers associated with cold air aloft just behind the front will continue precip chances into the afternoon hours. After that, subsidence and cold advection behind that system brings in dry conditions and cooler temperatures for Sunday night through Tuesday, with lows dipping into the upper 30s many places and highs in the low to mid 60s. Precip chances return to parts of eastern KS on Wednesday when weak low-level warm advection and a weak wave in northwest flow aloft interact. Latest ECMWF and GEM would indicate that the cool air at the surface is more entrenched in place than the GFS, thus have gone cooler than guidance for highs on Wednesday. Beyond Wednesday, considerable differences exist between 12Z GFS and ECMWF in upper flow pattern and precip chances. GFS and GFSEnsemble places us in a more favorable pattern for a couple days of precip for Thursday and Friday, while the ECMWF is slower in bringing a shortwave trough out of the southwest U.S., and would give us the better chances on Friday. Have gone with a general compromise with 25 to 40 percent POPs for those days. && .AVIATION...(For the 00Z TAFs through 00Z Saturday Evening) Issued at 625 PM CDT FRI APR 17 2015 VFR prevails through at least the first 6 hours of the forecast period. Activity forming across western and southern Kansas is expected to impact sites after 06Z. Forecast soundings denote mostly showers with a few thunderstorms. After 09Z, coverage increases across the area with rain saturating conditions to MVFR through Saturday morning. Showers exit eastward as uncertainty increases for the afternoon in timing of next round for thunderstorms. Have a VCTS mention with improvement to VFR for the time being. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...53 LONG TERM...GDP AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
121 PM CDT THU APR 16 2015 ...UPDATED SHORT TERM SECTION... .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 120 PM CDT THU APR 16 2015 IN THE SHORT TERM, A FEW (2-3) ROUNDS OF CONVECTION ARE ANTICIPATED THROUGH HE NEXT 24 TO 36 HOURS OR SO AS A LARGE UPPER LOW MOVES TOWARD THE REGION WITH FORCING FOR ASCENT, AND PERSISTENT MID LEVEL MOISTURE ADVECTION TO MAINTAIN INSTABILITY FOR A PROLONGED PERIOD. THE FIRST ROUNDS ARE EXPECTED ALREADY EARLY THIS AFTERNOON AS THE NESTED 4 KM NAM AND HRRR MODELS HAVE GENERALLY AGREED ON CONVECTIVE INITIATION BETWEEN AROUND 2 AND 4 PM, AND RAPIDLY DEVELOPING INTO A MULTICELLULAR LINE AFTER AN HOUR OR SO OF SLOWER GROWING DISCREET CELLS. THE INITIAL ROTATING STORMS GENERALLY WEST OF HIGHWAY 83 SHOULD BE CAPABLE OF PRODUCING HAIL LARGER THAN GOLFBALLS AND DAMAGING WIND BEFORE THE STORMS BECOME MORE CLUSTERED OR LINEAR, PRESENTING A SLIGHTLY SMALLER HAIL THREAT AND STILL DAMAGING WIND THREAT THROUGH THE HIGHWAY 283 AND 183 CORRIDORS INTO THE EARLY EVENING HOURS. THESE MODEL SOLUTIONS COULD BE INTERFERED WITH BY THE EXTENSIVE STRATUS ACROSS THE AREA REDUCING THE SEVERE THREAT. ANOTHER ROUND OF THUNDERSTORMS WILL PROBABLY OCCUR LATE TONIGHT INTO THE OVERNIGHT AND POSSIBLY STILL ONGOING EARLY FRIDAY MORNING, WITH A CONTINUED HAIL IF NOT AN ISOLATED WIND THREAT AS WELL, ALTHOUGH SOME BL STABILITY SHOULD HINDER THE WIND THREAT. THE DYNAMICS OF THE UPPER LOW WILL DRIVE A DRY SLOT THROUGH THE REGION OF FRIDAY, BUT NOT BEFORE LATE MORNING/EARLY AFTERNOON DESTABILIZATION CONTRIBUTES TO YET ANOTHER SEVERE EPISODE WITH AS GOOD OR BETTER CAPE AND SHEAR COMBINATIONS. TEMPERATURES WERE RAISED FOR FRIDAY MORNING, FOLLOWING THE NAM AND GFS, AS OVERNIGHT CONVECTION SHOULD LIMIT THE RADIATIONAL COOLING. ADDITIONALLY THE POPS WERE RAISED LOWERED FRIDAY MORNING AND INCREASED ALONG THE MOISTURE TRANSPORT AXIS INTO FRIDAY AFTERNOON WITH A MODEL CONSENSUS. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 1152 AM CDT THU APR 16 2015 FRIDAY NIGHT INTO SATURDAY WE WILL STILL BE DEALING WITH THE SLOW- MOVING UPPER LOW, BUT BY THIS TIME THE LOW WILL BE SEVERELY OCCLUDED WITH THE DRY INTRUSION WORKING IN FAST FROM THE SOUTHWEST. IN FACT, FRIDAY NIGHT LOOKS RATHER DRY NOW WITH THE SYNOPTIC DRY INTRUSION ACROSS MUCH OF KANSAS. WE HAVE REDUCED POPS AS A RESULT FRIDAY NIGHT. AS WE HEAD INTO SATURDAY, ANY DAYTIME HEATING WILL PROMOTE SHOWER AND ISOLATED THUNDERSTORM DEVELOPMENT AS THE CORE OF THE MID LEVEL CYCLONE WALLOWS SLOWLY EASTWARD INTO FAR WESTERN KANSAS. WE WILL MAINTAIN THE 20-40 POPS ACROSS MAINLY THE NORTHERN AND EASTERN ZONES WITH A DRY FORECAST ACROSS FAR SOUTHWEST KANSAS. WHAT IS LEFT OF THE LOW WILL FINALLY PULL AWAY SATURDAY NIGHT INTO EARLY SUNDAY WITH FAIRLY STRONG NORTH WINDS TO FOLLOW DURING THE DAY SUNDAY. WE COULD STILL SEE SOME WRAP-AROUND LIGHT PRECIPITATION IN THE WEAKENING MID LEVEL DEFORMATION AXIS, HENCE THE 20 TOP 30 POPS FOR MUCH OF THE AREA. LOOKING BEYOND THE WEEKEND, WE WILL ENTER A NORTHWEST FLOW PATTERN ON THE SOUTHWEST SIDE OF A LARGE-SCALE UPPER TROUGH ACROSS THE GREAT LAKES REGION. THE ATMOSPHERE WILL BE FAIRLY COOL EARLY NEXT WEEK AS A RESULT WITH LARGE SCALE HIGH PRESSURE AT THE SURFACE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 112 PM CDT THU APR 16 2015 SEVERE STORMS ARE EXPECTED LATER THIS AFTERNOON AND EARLY EVENING, AND WILL BE ACCOUNTED FOR IN LOCAL TERMINALS. THE CONVECTION IS MODELED BY THE CONVECTIVE ALLOWING MODELS TO GO FAIRLY MULTICELLULAR, OR A BROKEN LINE WITH BOTH HAIL AND WIND THREAT EARLY INTO THE EVENING, BUT BEGINNING AS ISOLATED TO SCATTERED AS EARLY AS 20-22 UTC. && .PRELIMINARY POINT TEMPS/POPS... DDC 54 70 49 69 / 70 60 60 50 GCK 52 68 44 69 / 60 60 60 40 EHA 51 67 42 66 / 60 30 30 30 LBL 54 70 46 69 / 60 50 40 30 HYS 53 69 49 71 / 80 70 60 50 P28 56 71 54 72 / 70 60 60 50 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...RUSSELL LONG TERM...UMSCHEID AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS JACKSON KY
616 PM EDT THU APR 16 2015 .UPDATE... ISSUED AT 615 PM EDT THU APR 16 2015 UPDATED POPS FROM FRIDAY INTO SATURDAY. LATEST MODEL RUNS SUGGEST THE TIME FRAME FROM LATE FRIDAY THROUGH SATURDAY WILL LIKELY BE DRY. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 306 PM EDT THU APR 16 2015 WITH THE LATEST RUN OF THE HRRR MODEL BEING A BIT OFF WITH ITS HANDLING OF TODAYS CONVECTION...THE NAM12 WAS MODEL OF CHOICE FOR THE SHORT TERM PORTION OF THE FORECAST. SHOWERS AND STORMS THAT HAVE BEEN MOVING ACROSS EASTERN KENTUCKY THROUGHOUT THE DAY ARE CURRENTLY AFFECTING THE NORTHEASTERN PORTION OF THE THE AREA. THIS ACTIVITY IS EXPECTED TO MOVE ON OUT OF THE AREA IN THE NEXT FEW HOURS. CURRENT RADAR INDICATES THAT ISOLATED TO SCATTERED SHOWERS AND STORMS WILL CONTINUE TO MOVE INTO THE AREA FROM THE SOUTHWEST DURING THE REMAINDER OF THE AFTERNOON AND EVENING HOURS. ONLY ISOLATED ACTIVITY...IF THAT...WILL BE LEFT OVER FOR THE OVERNIGHT HOURS. SHOWERS AND STORMS WILL BE POSSIBLE DURING THE DAY ON FRIDAY...AS A WEAK FRONTAL BOUNDARY MOVES IN FROM THE WEST. WEAK DISTURBANCES AHEAD OF THIS FRONT MAY ALSO KICK OFF SHOWERS AND STORMS...BUT WITH A LACK OF INSTABILITY AND STRONG LIFT...IT APPEARS THAT THE COVERAGE OF PRECIPITATION WILL BE SPARSE. BASED ON THE LATEST MODEL DATA...THERE SHOULD BE LULL IN THE ACTION FROM LATE FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING...AS A WEAK RIDGE OF HIGH PRESSURE BRIEFLY SETTLES OVER THE AREA. TEMPERATURES DURING THE PERIOD WILL BE WELL ABOVE NORMAL FOR THIS TIME OF YEAR...WITH HIGHS ON FRIDAY MAXING OUT IN THE 70S...AND OVERNIGHT LOWS TONIGHT AND FRIDAY NIGHT BOTTOMING OUT IN THE LOW TO MID 50S AREA WIDE. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 340 PM EDT THU APR 16 2015 MAIN CONCERN DURING THE EXTENDED PERIOD IS FOCUSED ON A CUT OFF LOW CURRENTLY OVER THE FOUR CORNERS REGION. THIS LOW IS PROGGED TO PUSH SLOWLY EWD EARLY SATURDAY BEFORE ITS ENERGY GETS INGESTED AND HELPS DEEPEN A NORTHERN STREAM TROUGH. THIS TROUGH WILL MOVE ALONG THE US/CANADIAN BORDER UNTIL THE CLOSED LOW ENERGY PHASES WITH IT AND MOVES EAST. IN ADDITION TO THE UPPER LEVEL TROUGH...A SFC LOW IS FORECASTED TO DEVELOP SATURDAY NIGHT OVER THE PLAINS AND AHEAD OF IT...A STRONG SURGE OF GULF MOISTURE RETURNS TO THE OH AND TN VALLEYS. PW VALUES UP TO 1.4 INCHES ARE EXPECTED WITH THIS NEW SURGE OF MOISTURE....WHICH ARE WELL ABOVE AVERAGE. THERE WILL BE SOME MODERATE INSTABILITY AS WELL. THIS SYSTEM SHOULD PUSH OUT OF KY BY MONDAY NIGHT. ON TUESDAY...A LOW THAT IS NOW CUT OFF IN THE NORTHERN STREAM WILL UNDULATE OVER THE GREAT LAKES REGION THROUGH THURSDAY WITH PIECES OF ENERGY WRAPPING AROUND IT. HOWEVER...THIS SHOULDN/T CAUSE ANY ISSUES FOR KENTUCKY AS THE ENERGY APPEARS TO STAY FURTHER NORTH UNTIL THURSDAY WHEN THE LOW STARTS SAGGING SOUTHEASTWARD. AT THE SFC...SATURDAY WILL BE MAINLY DRY AND WARM UNTIL LATE AFTERNOON WHEN CHANCES FOR PRECIP BEGIN INCREASING. THE BULK OF THE RAINFALL WILL FALL SUNDAY INTO MONDAY WHERE AT LEAST AN INCH OF LIQUID IS LIKELY ACROSS EASTERN KENTUCKY. THERE IS ALSO A CHANCE FOR THUNDERSTORMS DURING THIS TIME GIVEN THE MOIST AIR MASS IN PLACE AND PLENTY OF SFC/UPPER LEVEL DYNAMICS. AS THIS SYSTEM EXITS THE AREA MONDAY NIGHT...THINGS WILL DRY OUT AND EASTERN KENTUCKY WILL GET A REPRIEVE FROM PRECIPITATION TUESDAY AND WEDNESDAY. TEMPERATURES DURING THIS TIME WILL BE A BIT BELOW NORMAL IF NOT RIGHT AT SEASONABLE LEVELS. RAIN CHANCES RETURN ON THURSDAY AS THE LOW SAGS SOUTHEASTWARD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 145 PM EDT THU APR 16 2015 SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE ACROSS EASTERN KENTUCKY OVER THE NEXT SEVERAL HOURS. THE OVERALL TREND OVER THE PAST COUPLE OF HOURS HAS BEEN FOR THE ACTIVITY TO WEAKEN AND DECREASE IN COVERAGE. THAT BEING SAID...IT LOOKS THERE WILL BE A MUCH SMALLER CHANCE OF SHOWERS AND STORMS DIRECTLY AFFECTING ANY OF THE TAF SITES THAN BEFORE. WHERE RAIN DOES OCCUR...PARTICULARLY WITH THUNDERSTORMS...A TAF SITE MAY EXPERIENCE BRIEF PERIODS OF MVFR CONDITIONS DURING THE MORE INTENSE RAIN SHOWERS. THE SHOWERS AND STORMS SHOULD BE MOSTLY OUT OF THE ARE BY AROUND 2Z THIS EVENING. THERE WILL BE A CHANCE OF LINGERING SHOWERS AND STORMS OVERNIGHT...AS AN AREA OF DISTURBED WEATHER PASSES BY THE AREA. ANOTHER BATCH OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS IS ON TAP FOR TOMORROW...AS YET ANOTHER DISTURBANCE MOVES ACROSS THE OHIO AND TENNESSEE VALLEY REGIONS. THERE SHOULD BE A GOOD LULL IN THE RAIN BETWEEN ROUGHLY 2 AND 12Z...WITH A SLIGHT UPTICK IN THE ACTIVITY AT 12 OR 13Z. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HAL SHORT TERM...AR LONG TERM...JVM AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
340 PM EDT THU APR 16 2015 .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 306 PM EDT THU APR 16 2015 WITH THE LATEST RUN OF THE HRRR MODEL BEING A BIT OFF WITH ITS HANDLING OF TODAYS CONVECTION...THE NAM12 WAS MODEL OF CHOICE FOR THE SHORT TERM PORTION OF THE FORECAST. SHOWERS AND STORMS THAT HAVE BEEN MOVING ACROSS EASTERN KENTUCKY THROUGHOUT THE DAY ARE CURRENTLY AFFECTING THE NORTHEASTERN PORTION OF THE THE AREA. THIS ACTIVITY IS EXPECTED TO MOVE ON OUT OF THE AREA IN THE NEXT FEW HOURS. CURRENT RADAR INDICATES THAT ISOLATED TO SCATTERED SHOWERS AND STORMS WILL CONTINUE TO MOVE INTO THE AREA FROM THE SOUTHWEST DURING THE REMAINDER OF THE AFTERNOON AND EVENING HOURS. ONLY ISOLATED ACTIVITY...IF THAT...WILL BE LEFT OVER FOR THE OVERNIGHT HOURS. SHOWERS AND STORMS WILL BE POSSIBLE DURING THE DAY ON FRIDAY...AS A WEAK FRONTAL BOUNDARY MOVES IN FROM THE WEST. WEAK DISTURBANCES AHEAD OF THIS FRONT MAY ALSO KICK OFF SHOWERS AND STORMS...BUT WITH A LACK OF INSTABILITY AND STRONG LIFT...IT APPEARS THAT THE COVERAGE OF PRECIPITATION WILL BE SPARSE. BASED ON THE LATEST MODEL DATA...THERE SHOULD BE LULL IN THE ACTION FROM LATE FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING...AS A WEAK RIDGE OF HIGH PRESSURE BRIEFLY SETTLES OVER THE AREA. TEMPERATURES DURING THE PERIOD WILL BE WELL ABOVE NORMAL FOR THIS TIME OF YEAR...WITH HIGHS ON FRIDAY MAXING OUT IN THE 70S...AND OVERNIGHT LOWS TONIGHT AND FRIDAY NIGHT BOTTOMING OUT IN THE LOW TO MID 50S AREA WIDE. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 340 PM EDT THU APR 16 2015 MAIN CONCERN DURING THE EXTENDED PERIOD IS FOCUSED ON A CUT OFF LOW CURRENTLY OVER THE FOUR CORNERS REGION. THIS LOW IS PROGGED TO PUSH SLOWLY EWD EARLY SATURDAY BEFORE ITS ENERGY GETS INGESTED AND HELPS DEEPEN A NORTHERN STREAM TROUGH. THIS TROUGH WILL MOVE ALONG THE US/CANADIAN BORDER UNTIL THE CLOSED LOW ENERGY PHASES WITH IT AND MOVES EAST. IN ADDITION TO THE UPPER LEVEL TROUGH...A SFC LOW IS FORECASTED TO DEVELOP SATURDAY NIGHT OVER THE PLAINS AND AHEAD OF IT...A STRONG SURGE OF GULF MOISTURE RETURNS TO THE OH AND TN VALLEYS. PW VALUES UP TO 1.4 INCHES ARE EXPECTED WITH THIS NEW SURGE OF MOISTURE....WHICH ARE WELL ABOVE AVERAGE. THERE WILL BE SOME MODERATE INSTABILITY AS WELL. THIS SYSTEM SHOULD PUSH OUT OF KY BY MONDAY NIGHT. ON TUESDAY...A LOW THAT IS NOW CUT OFF IN THE NORTHERN STREAM WILL UNDULATE OVER THE GREAT LAKES REGION THROUGH THURSDAY WITH PIECES OF ENERGY WRAPPING AROUND IT. HOWEVER...THIS SHOULDN/T CAUSE ANY ISSUES FOR KENTUCKY AS THE ENERGY APPEARS TO STAY FURTHER NORTH UNTIL THURSDAY WHEN THE LOW STARTS SAGGING SOUTHEASTWARD. AT THE SFC...SATURDAY WILL BE MAINLY DRY AND WARM UNTIL LATE AFTERNOON WHEN CHANCES FOR PRECIP BEGIN INCREASING. THE BULK OF THE RAINFALL WILL FALL SUNDAY INTO MONDAY WHERE AT LEAST AN INCH OF LIQUID IS LIKELY ACROSS EASTERN KENTUCKY. THERE IS ALSO A CHANCE FOR THUNDERSTORMS DURING THIS TIME GIVEN THE MOIST AIR MASS IN PLACE AND PLENTY OF SFC/UPPER LEVEL DYNAMICS. AS THIS SYSTEM EXITS THE AREA MONDAY NIGHT...THINGS WILL DRY OUT AND EASTERN KENTUCKY WILL GET A REPRIEVE FROM PRECIPITATION TUESDAY AND WEDNESDAY. TEMPERATURES DURING THIS TIME WILL BE A BIT BELOW NORMAL IF NOT RIGHT AT SEASONABLE LEVELS. RAIN CHANCES RETURN ON THURSDAY AS THE LOW SAGS SOUTHEASTWARD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 145 PM EDT THU APR 16 2015 SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE ACROSS EASTERN KENTUCKY OVER THE NEXT SEVERAL HOURS. THE OVERALL TREND OVER THE PAST COUPLE OF HOURS HAS BEEN FOR THE ACTIVITY TO WEAKEN AND DECREASE IN COVERAGE. THAT BEING SAID...IT LOOKS THERE WILL BE A MUCH SMALLER CHANCE OF SHOWERS AND STORMS DIRECTLY AFFECTING ANY OF THE TAF SITES THAN BEFORE. WHERE RAIN DOES OCCUR...PARTICULARLY WITH THUNDERSTORMS...A TAF SITE MAY EXPERIENCE BRIEF PERIODS OF MVFR CONDITIONS DURING THE MORE INTENSE RAIN SHOWERS. THE SHOWERS AND STORMS SHOULD BE MOSTLY OUT OF THE ARE BY AROUND 2Z THIS EVENING. THERE WILL BE A CHANCE OF LINGERING SHOWERS AND STORMS OVERNIGHT...AS AN AREA OF DISTURBED WEATHER PASSES BY THE AREA. ANOTHER BATCH OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS IS ON TAP FOR TOMORROW...AS YET ANOTHER DISTURBANCE MOVES ACROSS THE OHIO AND TENNESSEE VALLEY REGIONS. THERE SHOULD BE A GOOD LULL IN THE RAIN BETWEEN ROUGHLY 2 AND 12Z...WITH A SLIGHT UPTICK IN THE ACTIVITY AT 12 OR 13Z. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...AR LONG TERM...JVM AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
306 PM EDT THU APR 16 2015 .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 306 PM EDT THU APR 16 2015 WITH THE LATEST RUN OF THE HRRR MODEL BEING A BIT OFF WITH ITS HANDLING OF TODAYS CONVECTION...THE NAM12 WAS MODEL OF CHOICE FOR THE SHORT TERM PORTION OF THE FORECAST. SHOWERS AND STORMS THAT HAVE BEEN MOVING ACROSS EASTERN KENTUCKY THROUGHOUT THE DAY ARE CURRENTLY AFFECTING THE NORTHEASTERN PORTION OF THE THE AREA. THIS ACTIVITY IS EXPECTED TO MOVE ON OUT OF THE AREA IN THE NEXT FEW HOURS. CURRENT RADAR INDICATES THAT ISOLATED TO SCATTERED SHOWERS AND STORMS WILL CONTINUE TO MOVE INTO THE AREA FROM THE SOUTHWEST DURING THE REMAINDER OF THE AFTERNOON AND EVENING HOURS. ONLY ISOLATED ACTIVITY...IF THAT...WILL BE LEFT OVER FOR THE OVERNIGHT HOURS. SHOWERS AND STORMS WILL BE POSSIBLE DURING THE DAY ON FRIDAY...AS A WEAK FRONTAL BOUNDARY MOVES IN FROM THE WEST. WEAK DISTURBANCES AHEAD OF THIS FRONT MAY ALSO KICK OFF SHOWERS AND STORMS...BUT WITH A LACK OF INSTABILITY AND STRONG LIFT...IT APPEARS THAT THE COVERAGE OF PRECIPITATION WILL BE SPARSE. BASED ON THE LATEST MODEL DATA...THERE SHOULD BE LULL IN THE ACTION FROM LATE FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING...AS A WEAK RIDGE OF HIGH PRESSURE BRIEFLY SETTLES OVER THE AREA. TEMPERATURES DURING THE PERIOD WILL BE WELL ABOVE NORMAL FOR THIS TIME OF YEAR...WITH HIGHS ON FRIDAY MAXING OUT IN THE 70S...AND OVERNIGHT LOWS TONIGHT AND FRIDAY NIGHT BOTTOMING OUT IN THE LOW TO MID 50S AREA WIDE. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 355 AM EDT THU APR 16 2015 THE UPPER LEVEL PATTERN REMAINS IN A SPLIT FLOW TO START THE EXTENDED WITH MAIN CONCERNS CENTERED AROUND A CLOSED LOW WHICH IS IN THE PROCESS OF CREEPING EAST FROM THE FOUR CORNERS REGION ON FRIDAY NIGHT. MEANWHILE...ALONG THE NORTHERN JET STREAM...A STRONG SHORTWAVE IS CURRENTLY ENTERING THE PACIFIC NORTHWEST. AS THE MENTIONED CLOSED LOW OPENS AND EJECTS TO THE EAST...THESE TWO FEATURES BEGIN TO PHASE...DEEPENING THE LONGWAVE TROUGH OVER THE CENTRAL PLAINS AS THIS FEATURE MOVES EAST. CLOSER TO EAST KENTUCKY DURING THE FRIDAY NIGHT THROUGH SATURDAY TIME FRAME...WEAK DISTURBANCES ALONG THE SOUTHERN STREAM MOVING INTO THE AREA WILL KEEP A SLIGHT CHANCE OF PRECIP FRIDAY NIGHT OVER THE AREA. BY SATURDAY NIGHT...AS THE MENTIONED DEEPENING TROUGH DEVELOPS...A STRONG SURFACE LOW PRESSURE DEVELOPS OVER THE PLAINS AND A STRONG SURGE OF MOISTURE MOVES NORTHEAST INTO THE TN AND OH VALLEYS SATURDAY NIGHT AND SUNDAY BEHIND A DEVELOPED WARM FRONT. PWATS WITH THIS LOOK TO BE NEAR 1.40 INCHES IN MOST EAST KENTUCKY LOCATIONS WITH SOME MODEST INSTABILITY THROUGH SUNDAY. CONCERNING THIS...THE GFS AND EURO HAVE HAD GOOD AGREEMENT WITH THIS FEATURE AND CONSISTENCY AS WELL. IN FACT...MOS DATA HAS BEEN ADVERTISING CAT POPS ACROSS EAST KENTUCKY. COLLABORATING WITH NEIGHBORS AND WHAT THE MODELS HAVE SHOWN...HAVE GONE ABOVE WHAT THE SUPER BLEND HAS DISPLAYED FOR EAST KENTUCKY. DESPITE THE DOWNSLOPE FOR THE BEGINNING OF THIS EVENT LATE SATURDAY NIGHT...THE SURGE IN MOISTURE WITH THIS WILL QUICKLY OVERTAKE THIS ADIABATIC PROCESS. BESIDE THE MOISTURE AVAILABLE AND POSSIBLE FLOOD SCENARIO...THE AMOUNT OF SHEAR THE MODEL SOUNDINGS ARE ADVERTISING IS CONCERNING. THE ONLY INHIBITING FACTOR HERE IS THE TIMING OF THE PRECIP AND LACK OF STRONG INSTABILITY. NEVERTHELESS...WILL GO WITH CAT POPS LATE SATURDAY NIGHT THROUGH SUNDAY AFTERNOON AND LIKELY POPS THROUGH MONDAY AS ADDITIONAL MOISTURE MOVES INTO THE AREA. THIS TIME FRAME WILL CONTINUE TO BE HIGHLIGHTED IN THE HWO FOR POSSIBLE FLOODING AND MAY NEED TO HIGHLIGHT A SEVERE POTENTIAL...THOUGH THIS ELEMENT IS STILL VAGUE DUE TO THE TIMING...LACK OF DEEP INSTABILITY...AND TIMING WITH THE BETTER UPPER LEVEL DYNAMICS ARRIVING LATE IN THE PERIOD. CONTINUED PRECIP WILL LAST INTO MONDAY AND MONDAY NIGHT AS THE SURFACE COLD FRONT BEGINS TO PUSH THROUGH. LOOKING AT MODEL SOUNDINGS MONDAY INTO MONDAY NIGHT...ANOTHER PERIOD OF UNSETTLED WEATHER LOOKS POSSIBLE. HIGH PRESSURE AND RARE QUIET WEATHER WILL ARRIVE INTO THE AREA BEHIND THE FRONT FOR THE TUESDAY AFTERNOON THROUGH WEDNESDAY PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 145 PM EDT THU APR 16 2015 SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE ACROSS EASTERN KENTUCKY OVER THE NEXT SEVERAL HOURS. THE OVERALL TREND OVER THE PAST COUPLE OF HOURS HAS BEEN FOR THE ACTIVITY TO WEAKEN AND DECREASE IN COVERAGE. THAT BEING SAID...IT LOOKS THERE WILL BE A MUCH SMALLER CHANCE OF SHOWERS AND STORMS DIRECTLY AFFECTING ANY OF THE TAF SITES THAN BEFORE. WHERE RAIN DOES OCCUR...PARTICULARLY WITH THUNDERSTORMS...A TAF SITE MAY EXPERIENCE BREIF PERIODS OF MVFR CONDITIONS DURING THE MORE INTENSE RAIN SHOWERS. THE SHOWERS AND STORMS SHOULD BE MOSTLY OUT OF THE ARE BY AROUND 2Z THIS EVENING. THERE WILL BE A CHANCE OF LINGERING SHOWERS AND STORMS OVERNIGHT...AS AN AREA OF DISTURBED WEATHER PASSES BY THE AREA. ANOTHER BATCH OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS IS ON TAP FOR TOMORROW...AS YET ANOTHER DISTURBANCE MOVES ACROSS THE OHIO AND TENNESSEE VALLEY REGIONS. THERE SHOULD BE A GOOD LULL IN THE RAIN BETWEEN ROUGHLY 2 AND 12Z...WITH A SLIGHT UPTICK IN THE ACTIVITY AT 12 OR 13Z. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...AR LONG TERM...SHALLENBERGER AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
213 AM EDT THU APR 16 2015 .UPDATE... ISSUED AT 213 AM EDT THU APR 16 2015 SHOWERS ARE BEGINNING TO MOVE INTO THE LAKE CUMBERLAND REGION IN RESPONSE TO AN APPROACHING UPPER LEVEL SHORTWAVE. SHOWER COVERAGE IS EXPECTED TO GRADUALLY INCREASE THROUGH THE MORNING AS THIS SHORTWAVE MOVES THROUGH THE AREA. NEAR TERM MODELS INDICATE TWO WAVES OF SHOWERS AND A FEW THUNDERSTORMS TODAY AND POPS WERE ADJUSTED TO ACCOUNT FOR THE MORNING PRECIP...FOLLOWED BY A BRIEF LULL AND THEN ANOTHER UPTICK IN SHOWERS AND A FEW THUNDERSTORMS IN THE AFTERNOON. WE SHOULD NOT BE ABLE TO ACHIEVE THE AMOUNT OF INSTABILITY CURRENTLY FOUND OVER WESTERN AND CENTRAL TENNESSEE TODAY...SO DO NOT ANTICIPATE THE STRONG TO OCCASIONALLY SEVERE THUNDERSTORMS FOUND THERE TO BE ABLE TO MAINTAIN THERE STRENGTH THIS FAR NORTH AND EAST. UPDATE ISSUED AT 941 PM EDT WED APR 15 2015 GENERALLY ISOLATED SHOWERS CONTINUE ACROSS THE CWA LATE THIS EVENING..WITH MORE SCATTERED ACTIVITY ACROSS THE NORTH CENTRAL PORTION OF THE STATE ALONG A WEAK BOUNDARY. HEAVIER SHOWERS AND THUNDERSTORMS REMAIN WELL TO OUR SOUTHWEST ACROSS WESTERN TN...CLOSER TO THE SURFACE LOW PRESSURE CENTER LOCATED NEAR THE SAME AREA. THIS LOW WILL CONTINUE TO SLOWLY SHIFT NE THROUGHOUT THE NIGHT...REACHING FAR WESTERN KY BY 12Z TOMORROW. THIS MAY ALLOW SOME MORE SHOWERS AND POSSIBLY EVEN AN ISOLATED THUNDERSTORM TO DEVELOP AND MOVE INTO THE CWA LATER IN THE NIGHT AND EARLY IN THE MORNING. BUT IN THE MEANTIME...IT LOOKS AS THINGS ARE STARTING TO SETTLE DOWN ACROSS THE REGION. CONTINUED CLOUD COVER...A HIGH AMOUNT OF MOISTURE...AND LIGHT WINDS...WILL HELP TO MODERATE THE TEMPERATURES OVERNIGHT. CURRENT READINGS OF UPPER 50S HAVE BEEN INCORPORATED INTO THE NEAR TERM FORECAST...WITH ONLY A 3 TO 5 DEGREE DIURNAL FALL INTO THE LOW TO MID 50S EXPECTED BY MORNING. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 340 PM EDT WED APR 15 2015 18Z SFC ANALYSIS SHOWS THAT THE INVERTED TROUGH AXIS HAS SHIFTED EAST TO ALONG THE SPINE OF THE APPALACHIANS WITH THE LOWER MISSISSIPPI VALLEY LOW/S WARM FRONT LIFTING NORTH INTO KENTUCKY. THE LIGHT PCPN AND OVERCAST CONDITIONS HAS KEPT MOST OF THE AREA ON THE COOL SIDE TODAY...ESPECIALLY OUTSIDE OF THE CUMBERLAND VALLEY. HOWEVER...THINNING CLOUDS AND A BREAK IN THE LIGHT RAIN SHOULD ALLOW FOR SOME DECENT TEMP RISES OVER THE NEXT COUPLE OF HOURS FOR ALL BUT THE FAR NORTHEAST. READINGS CURRENTLY VARY FROM THE UPPER 50S IN THE NORTHEAST TO THE UPPER 60S IN THE SOUTH WHILE DEWPOINTS RANGE FROM NEAR 60 SOUTH TO THE UPPER 40S IN THE FAR NORTH. WINDS ARE GENERALLY FROM THE EAST TO NORTHEAST AT 10 TO 15 MPH OVER THE NORTHERN HALF OF THE AREA WHILE THEY ARE A BIT LIGHTER AND MORE VARIABLE TO THE SOUTH. THE LIFTING WARM FRONT MAY REINITIATE SHOWERS LATER IN THE AFTERNOON INTO THE EVENING... PER THE LATEST HRRR AND NAM12...BUT RIGHT NOW THE RADAR SCOPE IS PRETTY CLEAN. SHOULD CONVECTION REDEVELOP...SOME THUNDER MAY EVEN BE POSSIBLE GIVEN THE RISING TEMPS/INSTABILITY...ESPECIALLY IN THE SOUTH. THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION OF THE FORECAST AS A FEW CLUSTERS OF MID LEVEL ENERGY WILL BRUSH KENTUCKY AS THEY MOVE INTO THE OHIO VALLEY TONIGHT ON THE NORTHWEST FRINGE OF A BUILDING RIDGE. THE RIDGE FLATTENS A BIT ON THURSDAY AS ADDITIONAL ENERGY PASSES THROUGH NORTHERN KENTUCKY THAT AFTERNOON/OVERNIGHT AND INTO FRIDAY MORNING. TO THE WEST...A SLOW MOVING CLOSED LOW SPINS ESSENTIALLY IN PLACE NEAR THE FOUR CORNERS REGION OF THE COUNTRY...SERVING AS A SOURCE REGION FOR ENERGY ABLE TO ESCAPE AND DRIFT EAST IN THE SOUTHERN STREAM THAT CONTINUES TO DOMINATE KENTUCKY/S WX. GIVEN THE GENERAL MODEL AGREEMENT HAVE FOLLOWED A BLEND WITH A LEAN TOWARD THE HRRR AND NAM12 FOR WEATHER SPECIFICS DUE TO THEIR HIGHER RESOLUTION... THOUGH CURRENT CONDITIONS AND TRENDS ARE ALSO OF HIGH RELEVANCE INTO THE NEAR TERM PORTION OF THE FORECAST. SENSIBLE WEATHER WILL FEATURE A POTENTIAL FOR SHOWERS INTO THE EVENING AS THE SFC FRONT LIFTS NORTHEAST THROUGH THE AREA WITH A THUNDERSTORM POSSIBLE...AS WELL. ADDITIONAL CONVECTION WILL BE POSSIBLE INTO THURSDAY MORNING WITH THE SFC LOW TO THE SOUTHWEST APPROACHING. THIS WILL LIKELY LIFT ANOTHER BOUNDARY THROUGH EASTERN KENTUCKY DURING THE DAY WITH SHOWERS AND STRAY STORMS A GOOD BET. THE PCPN CHANCES WILL DIMINISH INTO FRIDAY MORNING BUT CANNOT GO DRY ATTM GIVEN THE ENVIRONMENT. THIS REMAINS A LOW CONFIDENCE FORECAST WITH RESPECT TO SPECIFIC DETAILS BUT IN GENERAL YOU CAB BANK ON RELATIVELY WARM AND MOIST CONDITIONS CONTINUING. USED THE SHORTBLEND GUIDANCE AS A STARTING POINT FOR T/TD/WIND GRIDS THROUGH THE FIRST 18-24 HOURS OF THE FORECAST FOLLOWED BY THE SUPERBLEND. GIVEN THE HUMID CONDITIONS MADE ONLY MINOR TERRAIN BASED ADJUSTMENTS TO TEMPERATURES TONIGHT AND THURSDAY NIGHT. AS FOR POPS...ENDED UP ON THE LOW SIDE OF MOS GUIDANCE TONIGHT AND THURSDAY...BUT IN LINE FOR THURSDAY NIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 340 PM EDT WED APR 15 2015 THE EXTENDED PERIOD WILL BE DOMINATED BY A LARGE CLOSED LOW OVER THE FOUR CORNERS REGION WITH SOME SLIGHT RIDGING OVER THE EASTERN CONUS. AFTER A SHORT WAVE IMPULSE...PROVIDING A ROUND OF RAINFALL TO THE REGION...PUSHES THROUGH THE TN AND OH VALLEYS FRIDAY MORNING... FRIDAY EVENING INTO SATURDAY MORNING WILL BE MOSTLY DRY. ON SATURDAY...ANOTHER IMPULSE MOVING ALONG THE NORTHERN STREAM PUSHES EWD TOWARDS THE GREAT LAKES REGION. AT THE SAME TIME...THE CLOSED LOW EJECTS EWD AS WELL. THE ENERGY FROM THE CLOSED LOW THEN FEEDS INTO THE NORTHERN STREAM TROUGH AND HELPS DEEPEN/INTENSIFY IT. THIS SYSTEM WILL PROVIDE THE BEST CHANCE FOR A SIGNIFICANT AMOUNT OF RAINFALL FOR EASTERN KENTUCKY IN THE SATURDAY NIGHT THROUGH MONDAY MORNING TIME FRAME. THIS RAINFALL HAS THE POSSIBILITY OF BREAKING THE JKL/S ALL-TIME APRIL RAINFALL RECORD...CURRENTLY WE HAVE HAD THE SECOND WETTEST APRIL ON RECORD. IN FACT...THIS SYSTEM WILL SPREAD PRECIP FROM THE NORTHERN MISSISSIPPI VALLEY REGION ACROSS MOST OF THE EASTERN CONUS THROUGH TUESDAY. CLOSER TO HOME...TUESDAY AND WEDNESDAY LOOKS TO BE FAIRLY QUIET...COOLER...AND DRY AS THE UPPER LEVELS TRANSITION TO MORE OF A ZONAL FLOW PATTERN. GFS AND ECMWF MODELS ACTUALLY HAVE GOOD AGREEMENT WITH THE EVOLUTION OF THIS MAJOR SYSTEM. ADDITIONALLY...THERE LOOKS TO BE A STRONG SURGE OF GULF MOISTURE WITH PW VALUES REACHING 1.50 INCHES IN SOME LOCATIONS WITH SOME INSTABILITY PRESENT. THEREFORE...HAVE DECIDED TO INCLUDED SLIGHT CHANCES OF THUNDER THROUGHOUT THE EXTENDED PERIOD WITH LIKELY THUNDER DURING THE SUNDAY AFTERNOON THROUGH MONDAY MORNING TIME FRAME. PROBABLY COULD HAVE UPPED POPS TO GO CATEGORICAL ON SUNDAY/MONDAY MORNING BUT HAVE REMAINED CONSISTENT WITH NEIGHBORS FOR NOW AND KEPT LIKELY POPS IN THE GRIDS. ALL IN ALL...BASED ON THE CONTINUED WET PATTERN...THE MAIN CONCERN DURING THE EXTENDED PERIOD WILL BE HEAVY RAINFALL WITH LOCALIZED FLOODING CONCERNS...ESPECIALLY IN AREAS THAT RECEIVE SEVERAL ROUNDS OF RAINFALL AND WHERE RIVERS AND CREEKS ARE STILL RUNNING HIGH. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 213 AM EDT THU APR 16 2015 LOW LEVEL SOUTHEASTERLY FLOW HAS WORKED TO SCOUR OUT THE EARLIER LOW CLOUDS WITH MAINLY VFR CONDITIONS FOUND ACROSS EAST KENTUCKY AT THIS TIME. AN APPROACHING UPPER LEVEL DISTURBANCE WILL BRING AN INCREASE IN SHOWERS...AND MAYBE A THUNDERSTORM...THROUGH THE MORNING HOURS...WITH MVFR CONDITIONS LIKELY FOR A PERIOD OF TIME. THE MORNING SHOWERS SHOULD SHIFT TO OUR EAST DURING THE MIDDAY HOURS WITH VFR CONDITIONS EXPECTED AND JUST WIDELY SCATTERED SHOWERS LEFT BEHIND. NEAR TERM MODELS THEN INDICATE ADDITIONAL FORCING DURING THE AFTERNOON HOURS AND THIS MAY PRODUCE ANOTHER UPTICK IN SHOWER COVERAGE WITH A THUNDERSTORM OR TWO ALSO POSSIBLE. STILL UNSURE HOW WIDESPREAD THAT SECOND ROUND WILL BECOME SO JUST KEPT WITH A VCSH MENTION FROM MIDDAY ON IN THE TAFS FOR RIGHT NOW. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JMW/ABE SHORT TERM...GREIF LONG TERM...JVM AVIATION...ABE
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
832 AM CDT THU APR 16 2015 ...SOUNDING DISCUSSION... THE ATMOSPHERE CONTINUES TO REMAIN MOISTURE-LADEN WITH PRECIPITABLE WATER VALUES REMAINING WELL ABOVE NORMAL. THAT LINE WILL CONTINUE TO BE REPEATED THROUGH THE REST OF THE WEEK AND INTO THE WEEKEND. FORECAST CAPE VALUES WILL APPROACH 1500 J/KG AND LI WILL DROP TO -4 LATER TODAY. FREEZING LEVEL IS AROUND 12700 FEET...WHICH IS SIMILAR TO LAST EVENING. HOWEVER...WET BULB ZERO HEIGHT IS ABOUT 1000 FEET HIGHER THAN LAST NIGHT. THERE IS SOME DRY AIR SHOWN IN THE SOUNDING AROUND 17000 FEET THAT WOULD SUPPORT A DAMAGING WIND GUST POTENTIAL. MAIN FOCUS FOR TODAY WILL BE THREAT FOR HEAVY RAINFALL. THERE IS SOME DIRECTIONAL AND SPEED SHEAR...BUT STORM RELATIVE HELICITY VALUES ARE LOW SO TORNADO THREAT IS ALSO QUITE LOW. WINDS WERE FROM THE SOUTHEAST AT THE SURFACE AND THEN ROTATED AROUND TO THE WEST BY THE MIDLEVELS. A 29 KNOT WIND WAS OBSERVED AT 500MB AND A PEAK WIND SPEED OF 93 KNOTS WAS FOUND AT 38400 FEET/217MB. 12Z BALLOON INFO: NO ISSUES WITH THE FLIGHT THIS MORNING THAT LASTED 105 MINUTES. THE BALLOON REACHED A HEIGHT OF 21 MILES ABOVE THE GROUND AND WENT 53 MILES DOWNRANGE BURSTING EAST OF MCHENRY. ANSORGE && .PREV DISCUSSION... /ISSUED 414 AM CDT THU APR 16 2015/ SHORT TERM... LITTLE CHANGE IN THINKING FROM THE PREVIOUS FORECAST...AS THE AREA REMAINS UNDER THE INFLUENCE OF A BROAD REGION OF ENHANCED OMEGA THROUGH SATURDAY AS A SLOW MOVING UPPER LEVEL TROUGH OVER THE FOUR CORNERS DRIFTS THROUGH THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY. SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH PULSES UP INCREASED VORTICITY EJECTING OUT OF THE BASE OF THE PARENT UPPER LEVEL LOW WILL IMPACT THE REGION THROUGH THIS PERIOD...WITH THE RISK OF HEAVY RAINFALL AND LOCALLY SEVERE THUNDERSTORMS EACH DAY. HOWEVER... THE RISK OF SEVERE THUNDERSTORM DEVELOPMENT WILL BE GREATEST ON FRIDAY AND SATURDAY AS OVERALL LAPSE RATES AND SHEAR PROFILES LOOK MORE FAVORABLE ON THESE DAYS. THERE WILL BE A THREAT OF HEAVY RAINFALL THREAT EVERY DAY AS PW VALUES REMAIN ELEVATED AT AROUND 1.75 INCHES AND THE ATMOSPHERE REMAINS MOISTURE LOADED. GIVEN THIS THREAT...THE FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH FRIDAY EVENING. THE WATCH MAY NEED TO BE EXTENDED INTO SATURDAY LATER TODAY. FOR TODAY...AFTER REVIEWING THE GFSBUFR SOUNDINGS AND LOOKING AT THE LATEST HRRR OUTPUT...EXPECT TO SEE CONVECTION INITIALLY IMPACT AREAS AROUND BATON ROUGE THIS MORNING AND THEN SPREAD SOUTH AND EAST INTO NEW ORLEANS AND THE MISSISSIPPI GULF COAST DURING THE AFTERNOON AND EVENING HOURS. SOUNDING PROFILES ARE NOT AS SUPPORTIVE OF SEVERE THUNDERSTORMS TODAY...AS MID-LEVEL LAPSE RATES ARE CLOSER TO MOIST ADIABATIC AND THE WET BULB ZERO HEIGHT REMAINS AROUND 13K FEET. ADDITIONALLY...THERE IS VERY LITTLE WIND SHEAR NOTED OVER THE AREA. SPC HAS ONLY A MARGINAL RISK OF SEVERE THUNDERSTORM DEVELOPMENT TODAY GIVEN THESE WEAKER PARAMETERS. THE SOUNDING IS SUPPORTIVE OF LOCALLY HEAVY RAINFALL DEVELOPING TODAY. THERE IS LITTLE IN THE WAY OF CONVECTIVE INHIBITION...SO IT WILL NOT TAKE MUCH TO GET THUNDERSTORMS GOING. THESE THUNDERSTORMS WILL HAVE A VERY EFFICIENT RAIN PROCESS...WHICH WILL ALLOW FOR RAINFALL RATES OF UP TO 2 INCHES PER HOUR AT TIMES. THUS...SOME LOCALIZED FLOODING WILL BE THREAT TODAY. HEADING INTO TONIGHT...MUCH AS SEEN THE LAST FEW NIGHTS...THE THUNDERSTORM ACTIVITY WILL QUICKLY DIMINISH AS DAYTIME HEATING GIVES WAY. THERE WILL BE A RISK OF SOME SCATTERED SHOWERS AND B THUNDERSTORMS DEVELOPING DURING THE NIGHT...BUT OVERALL COVERAGE WILL BE MUCH LOWER THAN DURING THE PEAK HEATING HOURS. TEMPERATURES WILL ONCE AGAIN COOL BACK INTO THE MIDDLE TO UPPER 60S...AND SOME PATCHY FOG WILL DEVELOP TOWARD DAYBREAK DUE TO THE WET GROUND CONDITIONS AND A WEAK LOW LEVEL INVERSION CUTTING OFF THE BOUNDARY LAYER WINDS. FOG COVERAGE LOOKS TO BE LOW ENOUGH TO KEEP OUT OF THE OFFICIAL FORECAST FOR NOW. FRIDAY LOOKS TO BE A VERY ACTIVE DAY ACROSS THE REGION. GFSBUFR SOUNDINGS SHOW A MUCH MORE FAVORABLE ENVIRONMENT FOR SEVERE THUNDERSTORM DEVELOPMENT...ESPECIALLY FROM LATE MORNING ON. MID- LEVEL LAPSE RATES WILL INCREASE DRAMATICALLY FRIDAY AFTERNOON...SHOOTING UP TO 7 C/KM BETWEEN 700 AND 500 MB. THESE HIGH LAPSE RATES WILL ALSO BE ABOVE THE FREEZING LEVEL WHICH WILL FALL BELOW 13K FEET. ADDITIONALLY...WET BULB ZERO HEIGHTS WILL DROP TO AROUND 11K FEET. WITH STRONG LAPSE RATES IN THE HAIL GROWTH ZONE...SOME LARGE HAIL WILL ONCE AGAIN BE POSSIBLE ON FRIDAY. LOOKING AT THE WIND PROFILE...OVERALL HELICITY VALUES WILL BE FAIRLY WEAK ON FRIDAY...BUT WITH SOME DRY AIR ADVECTING INTO THE MID-LEVELS...THE THREAT OF STRAIGHT LINE WINDS AND BOWING SEGMENTS INCREASES. THERE IS ENOUGH LOW LEVEL HELICITY...THAT AN ISOLATED TORNADO COULD NOT BE RULED OUT FRIDAY AFTERNOON. OVERALL...EXPECT THE MAIN THREAT TO BE HAIL AND STRAIGHT LINE WINDS ON FRIDAY. CONDITIONS WILL ONCE AGAIN IMPROVE DURING THE EVENING HOURS ON FRIDAY AS THE VORT MAX SLIDES TO THE EAST AND THE ATMOSPHERE STABILIZES A BIT. HOWEVER...THE PARENT UPPER LEVEL TROUGH WILL BEGIN TO DIRECTLY IMPACT THE REGION ON SATURDAY AS IT MOVES THROUGH THE SOUTHERN PLAINS. SATURDAY LOOKS TO HAVE THE HIGHEST THREAT OF BOTH HEAVY RAINFALL AND SEVERE THUNDERSTORMS. PW VALUES WILL BE VERY HIGH...APPROACHING 2 INCHES...AND THE OVERALL LAPSE RATES WILL TURN MORE MOIST ADIABATIC THROUGH THE DAY. THIS WILL DECREASE THE HAIL THREAT SUBSTANTIALLY...WITH WET BULB ZERO HEIGHTS REMAINING WELL ABOVE 13K FEET. HOWEVER...VERY EFFICIENT RAINFALL PROCESSES WILL DEVELOP...RESULTING IN HOURLY RAINFALL RATE POTENTIAL OF 2 TO 3 INCHES IF A STORM STALLS OVER THE SAME AREA. FORTUNATELY...THE STORMS WILL BE FAST MOVING...SO ACTUAL RAINFALL RATES WILL BE LOWER. THESE STRONG WINDS WILL UNFORTUNATELY MEAN THAT THE RISK OF STRAIGHT LINE WINDS AND TORNADOES WILL BE HIGH ON SATURDAY. 0-3KM SHEAR WILL INCREASE TO AROUND 35 KNOTS AND STORM RELATIVE HELICITY VALUES WILL RISE TO AROUND 250 M2/S2 SATURDAY AFTERNOON. THESE VALUES ARE VERY CONDUCIVE TO ROTATING THUNDERSTORM DEVELOPMENT...AND THUS THE FORMATION OF TORNADOES. A FRONTAL BOUNDARY WILL PUSH THROUGH THE AREA SATURDAY NIGHT...WHICH WILL KEEP THE RISK OF SHOWERS AND THUNDERSTORMS IN PLACE THROUGH THE NIGHT...AND HAVE LIKELY POPS IN PLACE TO REFLECT THIS. LONG TERM... CONDITIONS WILL BEGIN TO IMPROVE ON SUNDAY...AS A COLD FRONT PUSHES OFFSHORE AND RAIN CHANCES SHOULD DECREASE THROUGH THE DAY FROM WEST TO EAST. THE PARENT UPPER LEVEL TROUGH AXIS WILL FINALLY PUSH THROUGH THE REGION SUNDAY NIGHT...WITH INCREASING NEGATIVE VORTICITY ADVECTION AND SUBSIDENCE TAKING HOLD OF THE AREA FOR MONDAY. AT MOST...THERE COULD BE SOME LINGERING SHOWERS AND CLOUDS ALONG THE IMMEDIATE COAST MONDAY MORNING...WITH CLEARING CONDITIONS EXPECTED BY MONDAY AFTERNOON. AS A MORE ZONAL FLOW REGIME TAKES HOLD ALOFT...AND SOME DRIER MID-LEVEL AIR LINGERS OVER THE AREA SKIES SHOULD REMAIN PARTLY CLOUDY AND RAIN CHANCES WILL BE LESS THAN 10 PERCENT FOR TUESDAY. TEMPERATURES WILL REMAIN NEAR NORMAL...WITH HIGHS IN THE LOWER 80S AND LOWS IN THE UPPER 50S AND LOWER 60S. UNFORTUNATELY...A WEAK IMPULSE RIDING ALONG THE ZONAL FLOW WILL SLIDE THROUGH THE AREA ON WEDNESDAY. THE SYSTEM WILL BE FAIRLY WEAK...BUT ENOUGH FORCING AND MOISTURE WILL BE IN PLACE TO SPARK OFF SOME SCATTERED SHOWERS AND THUNDERSTORMS DURING THE DAY ON WEDNESDAY. RAIN CHANCES WILL BE HIGHEST ALONG THE COAST AND OFFSHORE WHERE OVERALL MOISTURE AND FORCING IS EXPECTED TO BE GREATEST. AS THIS FEATURE PULLS TO THE EAST WEDNESDAY...SKIES SHOULD CLEAR AND RAIN CHANCES WILL DROP. HOWEVER...ANOTHER IMPULSE WILL SLIDE THROUGH ON THURSDAY...BRINGING ANOTHER CHANCE OF ISOLATED SHOWERS AND THUNDERSTORMS FOR THURSDAY. AVIATION... TAFS WILL BE DEPENDENT ONCE AGAIN ON EVENTUAL CONVECTIVE DEVELOPMENTS TODAY. CONVECTIVE BASED MODELS SUGGEST ONSET OF STORMS COULD IMPACT SOME LOCATIONS BY 14Z...PRIMARILY WESTERNMOST LOCATIONS LIKE KBTR AND KHUM...THOUGH ALL TERMINALS SHOULD SEE SOME PERIODS OF TSRA/SHRA THROUGHOUT THE DAY. DOWN BURST POTENTIAL WILL BE HIGH TODAY WITH GUST POTENTIAL 35-45 KT. EFFICIENT RAINFALL PROCESS SHOULD ALSO LOWER VSBY TO VLIFR LEVELS AT TIMES DURING HEAVY RAINFALL. OTHERWISE...VFR CONDITIONS SHOULD PREVAIL AFTER 16Z OUTSIDE CONVECTION. MARINE... AN INTERESTING WAKE LOW PHENOMENA IMPACTED THE OFFSHORE WATERS THIS MORNING...BUT THIS HAS SINCE WEAKENED. OVERALL...EXPECT TO SEE AN ONSHORE FLOW OF 10 TO 15 KNOTS REMAIN OVER THE COASTAL WATERS THROUGH FRIDAY. AS AN UPPER LEVEL LOW AND ASSOCIATED WEAK SURFACE LOW AND FRONT MOVE THROUGH OVER THE WEEKEND...WINDS WILL INCREASE INTO EXERCISE CAUTION RANGE SATURDAY AND REMAIN ELEVATED INTO SUNDAY. SEAS WILL RESPOND AND INCREASE TO 3 TO 5 FEET IN THE OFFSHORE WATERS. THE GRADIENT WILL EASE OVER THE AREA ON MONDAY...ALLOWING FOR WEAKER AND MORE VARIABLE FLOW OF 10 KNOTS OR LESS. SEAS WILL ALSO FALL BACK INTO THE 1 TO 3 FEET RANGE FOR MONDAY AND TUESDAY. DECISION SUPPORT... DSS CODE...BLUE. DEPLOYED...NONE. ACTIVATION...NONE. ACTIVITIES...MONITORING HEAVY RAINFALL/FLOODING POTENTIAL ASSESSING SEVERE WEATHER THREAT THRU WEEKEND. DECISION SUPPORT SERVICES (DSS) CODE LEGEND GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH VISIBILITY EVENT YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES RED = FULL ENGAGEMENT FOR MODERATE TONIGHT RISK SVR AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE && .PRELIMINARY POINT TEMPS/POPS... MCB 78 65 79 66 / 80 60 70 50 BTR 79 66 81 67 / 80 60 70 50 ASD 78 67 80 68 / 70 70 70 60 MSY 78 69 80 69 / 70 70 70 60 GPT 77 68 78 69 / 70 70 70 70 PQL 78 67 79 69 / 70 70 70 70 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR LAZ040-046>050- 056>070-072. GM...NONE. MS...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR MSZ077-080>082. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
414 AM CDT THU APR 16 2015 .SHORT TERM... LITTLE CHANGE IN THINKING FROM THE PREVIOUS FORECAST...AS THE AREA REMAINS UNDER THE INFLUENCE OF A BROAD REGION OF ENHANCED OMEGA THROUGH SATURDAY AS A SLOW MOVING UPPER LEVEL TROUGH OVER THE FOUR CORNERS DRIFTS THROUGH THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY. SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH PULSES UP INCREASED VORTICITY EJECTING OUT OF THE BASE OF THE PARENT UPPER LEVEL LOW WILL IMPACT THE REGION THROUGH THIS PERIOD...WITH THE RISK OF HEAVY RAINFALL AND LOCALLY SEVERE THUNDERSTORMS EACH DAY. HOWEVER... THE RISK OF SEVERE THUNDERSTORM DEVELOPMENT WILL BE GREATEST ON FRIDAY AND SATURDAY AS OVERALL LAPSE RATES AND SHEAR PROFILES LOOK MORE FAVORABLE ON THESE DAYS. THERE WILL BE A THREAT OF HEAVY RAINFALL THREAT EVERY DAY AS PW VALUES REMAIN ELEVATED AT AROUND 1.75 INCHES AND THE ATMOSPHERE REMAINS MOISTURE LOADED. GIVEN THIS THREAT...THE FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH FRIDAY EVENING. THE WATCH MAY NEED TO BE EXTENDED INTO SATURDAY LATER TODAY. FOR TODAY...AFTER REVIEWING THE GFSBUFR SOUNDINGS AND LOOKING AT THE LATEST HRRR OUTPUT...EXPECT TO SEE CONVECTION INITIALLY IMPACT AREAS AROUND BATON ROUGE THIS MORNING AND THEN SPREAD SOUTH AND EAST INTO NEW ORLEANS AND THE MISSISSIPPI GULF COAST DURING THE AFTERNOON AND EVENING HOURS. SOUNDING PROFILES ARE NOT AS SUPPORTIVE OF SEVERE THUNDERSTORMS TODAY...AS MID-LEVEL LAPSE RATES ARE CLOSER TO MOIST ADIABATIC AND THE WET BULB ZERO HEIGHT REMAINS AROUND 13K FEET. ADDITIONALLY...THERE IS VERY LITTLE WIND SHEAR NOTED OVER THE AREA. SPC HAS ONLY A MARGINAL RISK OF SEVERE THUNDERSTORM DEVELOPMENT TODAY GIVEN THESE WEAKER PARAMETERS. THE SOUNDING IS SUPPORTIVE OF LOCALLY HEAVY RAINFALL DEVELOPING TODAY. THERE IS LITTLE IN THE WAY OF CONVECTIVE INHIBITION...SO IT WILL NOT TAKE MUCH TO GET THUNDERSTORMS GOING. THESE THUNDERSTORMS WILL HAVE A VERY EFFICIENT RAIN PROCESS...WHICH WILL ALLOW FOR RAINFALL RATES OF UP TO 2 INCHES PER HOUR AT TIMES. THUS...SOME LOCALIZED FLOODING WILL BE THREAT TODAY. HEADING INTO TONIGHT...MUCH AS SEEN THE LAST FEW NIGHTS...THE THUNDERSTORM ACTIVITY WILL QUICKLY DIMINISH AS DAYTIME HEATING GIVES WAY. THERE WILL BE A RISK OF SOME SCATTERED SHOWERS AND B THUNDERSTORMS DEVELOPING DURING THE NIGHT...BUT OVERALL COVERAGE WILL BE MUCH LOWER THAN DURING THE PEAK HEATING HOURS. TEMPERATURES WILL ONCE AGAIN COOL BACK INTO THE MIDDLE TO UPPER 60S...AND SOME PATCHY FOG WILL DEVELOP TOWARD DAYBREAK DUE TO THE WET GROUND CONDITIONS AND A WEAK LOW LEVEL INVERSION CUTTING OFF THE BOUNDARY LAYER WINDS. FOG COVERAGE LOOKS TO BE LOW ENOUGH TO KEEP OUT OF THE OFFICIAL FORECAST FOR NOW. FRIDAY LOOKS TO BE A VERY ACTIVE DAY ACROSS THE REGION. GFSBUFR SOUNDINGS SHOW A MUCH MORE FAVORABLE ENVIRONMENT FOR SEVERE THUNDERSTORM DEVELOPMENT...ESPECIALLY FROM LATE MORNING ON. MID- LEVEL LAPSE RATES WILL INCREASE DRAMATICALLY FRIDAY AFTERNOON...SHOOTING UP TO 7 C/KM BETWEEN 700 AND 500 MB. THESE HIGH LAPSE RATES WILL ALSO BE ABOVE THE FREEZING LEVEL WHICH WILL FALL BELOW 13K FEET. ADDITIONALLY...WET BULB ZERO HEIGHTS WILL DROP TO AROUND 11K FEET. WITH STRONG LAPSE RATES IN THE HAIL GROWTH ZONE...SOME LARGE HAIL WILL ONCE AGAIN BE POSSIBLE ON FRIDAY. LOOKING AT THE WIND PROFILE...OVERALL HELICITY VALUES WILL BE FAIRLY WEAK ON FRIDAY...BUT WITH SOME DRY AIR ADVECTING INTO THE MID-LEVELS...THE THREAT OF STRAIGHT LINE WINDS AND BOWING SEGMENTS INCREASES. THERE IS ENOUGH LOW LEVEL HELICITY...THAT AN ISOLATED TORNADO COULD NOT BE RULED OUT FRIDAY AFTERNOON. OVERALL...EXPECT THE MAIN THREAT TO BE HAIL AND STRAIGHT LINE WINDS ON FRIDAY. CONDITIONS WILL ONCE AGAIN IMPROVE DURING THE EVENING HOURS ON FRIDAY AS THE VORT MAX SLIDES TO THE EAST AND THE ATMOSPHERE STABILIZES A BIT. HOWEVER...THE PARENT UPPER LEVEL TROUGH WILL BEGIN TO DIRECTLY IMPACT THE REGION ON SATURDAY AS IT MOVES THROUGH THE SOUTHERN PLAINS. SATURDAY LOOKS TO HAVE THE HIGHEST THREAT OF BOTH HEAVY RAINFALL AND SEVERE THUNDERSTORMS. PW VALUES WILL BE VERY HIGH...APPROACHING 2 INCHES...AND THE OVERALL LAPSE RATES WILL TURN MORE MOIST ADIABATIC THROUGH THE DAY. THIS WILL DECREASE THE HAIL THREAT SUBSTANTIALLY...WITH WET BULB ZERO HEIGHTS REMAINING WELL ABOVE 13K FEET. HOWEVER...VERY EFFICIENT RAINFALL PROCESSES WILL DEVELOP...RESULTING IN HOURLY RAINFALL RATE POTENTIAL OF 2 TO 3 INCHES IF A STORM STALLS OVER THE SAME AREA. FORTUNATELY...THE STORMS WILL BE FAST MOVING...SO ACTUAL RAINFALL RATES WILL BE LOWER. THESE STRONG WINDS WILL UNFORTUNATELY MEAN THAT THE RISK OF STRAIGHT LINE WINDS AND TORNADOES WILL BE HIGH ON SATURDAY. 0-3KM SHEAR WILL INCREASE TO AROUND 35 KNOTS AND STORM RELATIVE HELICITY VALUES WILL RISE TO AROUND 250 M2/S2 SATURDAY AFTERNOON. THESE VALUES ARE VERY CONDUCIVE TO ROTATING THUNDERSTORM DEVELOPMENT...AND THUS THE FORMATION OF TORNADOES. A FRONTAL BOUNDARY WILL PUSH THROUGH THE AREA SATURDAY NIGHT...WHICH WILL KEEP THE RISK OF SHOWERS AND THUNDERSTORMS IN PLACE THROUGH THE NIGHT...AND HAVE LIKELY POPS IN PLACE TO REFLECT THIS. .LONG TERM... CONDITIONS WILL BEGIN TO IMPROVE ON SUNDAY...AS A COLD FRONT PUSHES OFFSHORE AND RAIN CHANCES SHOULD DECREASE THROUGH THE DAY FROM WEST TO EAST. THE PARENT UPPER LEVEL TROUGH AXIS WILL FINALLY PUSH THROUGH THE REGION SUNDAY NIGHT...WITH INCREASING NEGATIVE VORTICITY ADVECTION AND SUBSIDENCE TAKING HOLD OF THE AREA FOR MONDAY. AT MOST...THERE COULD BE SOME LINGERING SHOWERS AND CLOUDS ALONG THE IMMEDIATE COAST MONDAY MORNING...WITH CLEARING CONDITIONS EXPECTED BY MONDAY AFTERNOON. AS A MORE ZONAL FLOW REGIME TAKES HOLD ALOFT...AND SOME DRIER MID-LEVEL AIR LINGERS OVER THE AREA SKIES SHOULD REMAIN PARTLY CLOUDY AND RAIN CHANCES WILL BE LESS THAN 10 PERCENT FOR TUESDAY. TEMPERATURES WILL REMAIN NEAR NORMAL...WITH HIGHS IN THE LOWER 80S AND LOWS IN THE UPPER 50S AND LOWER 60S. UNFORTUNATELY...A WEAK IMPULSE RIDING ALONG THE ZONAL FLOW WILL SLIDE THROUGH THE AREA ON WEDNESDAY. THE SYSTEM WILL BE FAIRLY WEAK...BUT ENOUGH FORCING AND MOISTURE WILL BE IN PLACE TO SPARK OFF SOME SCATTERED SHOWERS AND THUNDERSTORMS DURING THE DAY ON WEDNESDAY. RAIN CHANCES WILL BE HIGHEST ALONG THE COAST AND OFFSHORE WHERE OVERALL MOISTURE AND FORCING IS EXPECTED TO BE GREATEST. AS THIS FEATURE PULLS TO THE EAST WEDNESDAY...SKIES SHOULD CLEAR AND RAIN CHANCES WILL DROP. HOWEVER...ANOTHER IMPULSE WILL SLIDE THROUGH ON THURSDAY...BRINGING ANOTHER CHANCE OF ISOLATED SHOWERS AND THUNDERSTORMS FOR THURSDAY. && .AVIATION... TAFS WILL BE DEPENDENT ONCE AGAIN ON EVENTUAL CONVECTIVE DEVELOPMENTS TODAY. CONVECTIVE BASED MODELS SUGGEST ONSET OF STORMS COULD IMPACT SOME LOCATIONS BY 14Z...PRIMARILY WESTERNMOST LOCATIONS LIKE KBTR AND KHUM...THOUGH ALL TERMINALS SHOULD SEE SOME PERIODS OF TSRA/SHRA THROUGHOUT THE DAY. DOWN BURST POTENTIAL WILL BE HIGH TODAY WITH GUST POTENTIAL 35-45 KT. EFFICIENT RAINFALL PROCESS SHOULD ALSO LOWER VSBY TO VLIFR LEVELS AT TIMES DURING HEAVY RAINFALL. OTHERWISE...VFR CONDITIONS SHOULD PREVAIL AFTER 16Z OUTSIDE CONVECTION. && .MARINE... AN INTERESTING WAKE LOW PHENOMENA IMPACTED THE OFFSHORE WATERS THIS MORNING...BUT THIS HAS SINCE WEAKENED. OVERALL...EXPECT TO SEE AN ONSHORE FLOW OF 10 TO 15 KNOTS REMAIN OVER THE COASTAL WATERS THROUGH FRIDAY. AS AN UPPER LEVEL LOW AND ASSOCIATED WEAK SURFACE LOW AND FRONT MOVE THROUGH OVER THE WEEKEND...WINDS WILL INCREASE INTO EXERCISE CAUTION RANGE SATURDAY AND REMAIN ELEVATED INTO SUNDAY. SEAS WILL RESPOND AND INCREASE TO 3 TO 5 FEET IN THE OFFSHORE WATERS. THE GRADIENT WILL EASE OVER THE AREA ON MONDAY...ALLOWING FOR WEAKER AND MORE VARIABLE FLOW OF 10 KNOTS OR LESS. SEAS WILL ALSO FALL BACK INTO THE 1 TO 3 FEET RANGE FOR MONDAY AND TUESDAY. && .DECISION SUPPORT... DSS CODE...BLUE. DEPLOYED...NONE. ACTIVATION...NONE. ACTIVITIES...MONITORING HEAVY RAINFALL/FLOODING POTENTIAL ASSESSING SEVERE WEATHER THREAT THRU WEEKEND. DECISION SUPPORT SERVICES (DSS) CODE LEGEND GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH VISIBILITY EVENT YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES RED = FULL ENGAGEMENT FOR MODERATE TONIGHT RISK SVR AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE && .PRELIMINARY POINT TEMPS/POPS... MCB 78 65 79 66 / 80 60 70 50 BTR 79 66 81 67 / 80 60 70 50 ASD 78 67 80 68 / 70 70 70 60 MSY 78 69 80 69 / 70 70 70 60 GPT 77 68 78 69 / 70 70 70 70 PQL 78 67 79 69 / 70 70 70 70 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR LAZ040-046>050- 056>070-072. GM...NONE. MS...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR MSZ077-080>082. GM...NONE. && $$ 32
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
217 PM EDT THU APR 16 2015 .SYNOPSIS... A WEAK UPPER LEVEL DISTURBANCE AND TRAILING COLD FRONT WILL BRING SHOWERS THIS AFTERNOON INTO FRIDAY MORNING. HIGH PRESSURE WILL BRING A DRY START TO THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AREA OF SHOWERS HAS SPREAD ACROSS MUCH OF THE REGION AND WILL CONTINUE TO MOVE AND DEVELOP NORTHEAST INTO THE EVENING. UPPER LEVEL TROUGH MOVING INTO THE OHIO VALLEY THIS AFTERNOON WILL KEEP SHOWER CHANCES IN THE LIKELY CATEGORY UNTIL THIS EVENING WHEN UPPER TROUGH BEGINS TO SHEAR OUT AND A WEAK BOUNDARY APPROACHES FROM THE GREAT LAKES. SHOWERS WILL DIMINISH FROM WEST TO EAST OVERNIGHT AS DEEP MOISTURE IS TAKEN EAST OF THE RIDGES. TEMPERATURES WILL NOT MOVE MUCH FROM CURRENT READINGS WHERE RAIN HAS FALLEN. MIN TEMPS TONIGHT INTO THE 40S BUT STILL A BIT ABOVE AVERAGE. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... UPPER LEVEL SUPPORT WILL QUICKLY EXIT THE AREA...SO EXPECT THE SHOWERS TO RAP UP IN THE EAST FRIDAY MORNING. NO REAL DISCERNIBLE COLD ADVECTION IS EXPECTED...SO TEMPERATURES WILL BE ABLE TO REBOUND BACK TO...IF NOT WARMER THAN SEASONAL AVERAGES FRIDAY AFTERNOON. BROAD SURFACE HIGH AND UPPER LEVEL RIDGE WILL BUILD INTO THE OHIO VALLEY SATURDAY. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... MODELS STILL SHOWING A LARGE AND SLOW MOVING SYSTEM THAT WILL BRING AN EXTENDED PERIOD OF SHOWERS BEGINNING SUNDAY AND CONTINUING INTO EARLY TUESDAY. DRY AND SEASONABLE WEATHER WILL RETURN BEHIND THIS SYSTEM. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... SHOWERS WILL CONTINUE TO BLOSSOM WITH HELP FROM A PASSING SHORTWAVE THROUGH THIS AFTERNOON AND EVENING. A GRADUAL DETERIORATION TO MVFR AND IFR CIGS IS EXPECTED OVERNIGHT AT MOST PORTS AS THE WEAK FRONTAL BOUNDARY CROSSES. TRIED TO FOLLOW THE SREF PROBABILITIES AND BUFKIT MOISTURE PROFILES WITH TIMING OF RESTRICTIONS...AS THE NAM AND LAMP SEEM TO BE A BUT MORE PESSIMISTIC AT THIS TIME. WHILE VERY BRIEF IFR VISIBILITY MAY BE EXPECTED IN THE MORE INTENSE SHOWERS...OPTED TO NOT CARRY THIS AT ANY PARTICULAR SITE AND WILL COVER WITH TEMPOS AS NEEDED. A ESE TO WSW WIND SHIFT IS ANTICIPATED OVERNIGHT. GRADUAL IMPROVEMENT BACK TO MVFR WILL OCCUR TOMORROW. .OUTLOOK.../FRIDAY THROUGH TUESDAY/... THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH THE APPROACH OF LOW PRESSURE ON SUNDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
124 PM EDT THU APR 16 2015 .SYNOPSIS... A WEAK UPPER LEVEL DISTURBANCE AND TRAILING COLD FRONT WILL BRING SHOWERS THIS AFTERNOON INTO FRIDAY MORNING. HIGH PRESSURE WILL BRING A DRY START TO THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AREA OF SHOWERS HAS SPREAD ACROSS MUCH OF THE REGION AND WILL CONTINUE TO MOVE AND DEVELOP NORTHEAST INTO THE EVENING. UPPER LEVEL TROUGH MOVING INTO THE OHIO VALLEY THIS AFTERNOON WILL KEEP SHOWER CHANCES IN THE LIKLEY CATAGORY UNTIL THIS EVENING WHEN UPPER TROUGH BEGINS TO SHEAR OUT AND A WEAK BOUNDARY APPROACHES FROM THE GREAT ALKES. SHOWERS WILL DIMINISH FROM WEST TO EAST OVERNIGHT AS DEEP MOISTURE IS TAKEN EAST OF THE RIDGES. TEMPERATURES WILL NOT MOVE MUCH FROM CURRENT READINGS WHERE RAIN HAS FALLEN. MIN TEMPS TONIGHT INTO THE 40S BUT STILL A BIT ABOVE AVERAGE. && .SHORT TERM /FRIDAY THROUGH SATURDAY/... UPPER LEVEL SUPPORT WILL QUICKLY EXIT THE AREA...SO EXPECT THE SHOWERS TO RAP UP IN THE EAST FRIDAY MORNING. NO REAL DISCERNIBLE COLD ADVECTION IS EXPECTED...SO TEMPERATURES WILL BE ABLE TO REBOUND BACK TO...IF NOT WARMER THAN SEASONAL AVERAGES FRIDAY AFTERNOON. BROAD SURFACE HIGH AND UPPER LEVEL RIDGE WILL BUILD INTO THE OHIO VALLEY SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... MODELS STILL SHOWING A LARGE AND SLOW MOVING SYSTEM THAT WILL BRING AN EXTENDED PERIOD OF SHOWERS BEGINNING SUNDAY AND CONTINUING INTO EARLY TUESDAY. DRY AND SEASONABLE WEATHER WILL RETURN BEHIND THIS SYSTEM. && .AVIATION /17Z THURSDAY THROUGH MONDAY/... LOCAL MVFR CONDITIONS IN SCATTERED SHOWERS THIS AFTERNOON. INCREASING ESE TURNING SOUTH WINDS SHOULD PRECLUDE VISIBLITY RESTRICTIONS...HOWEVER CIGS WILL TREND AT LEAST CLOSE TO IFR BY TONIGHT AS LOW LEVELS BECOME SATURATED. .OUTLOOK.../FRIDAY THROUGH MONDAY/... THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH THE APPROACH OF LOW PRESSURE ON SUNDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1020 AM EDT THU APR 16 2015 .SYNOPSIS... A WEAK UPPER LEVEL DISTURBANCE AND TRAILING COLD FRONT WILL BRING SHOWERS THIS AFTERNOON INTO FRIDAY MORNING. HIGH PRESSURE WILL BRING A DRY START TO THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... ONLY CHANGES WERE TO MAX TEMPS AND HOURLY TEMPS. WHERE SHOWERS HAVE ARRIVED TEMPERATURES HAVE DROPPED OFF DUE TO WET BULBING...WHILE AREAS NORTH AND EAST OF KPIT I-80 REMAIN WARMER WITH SOME SUNSHINE. PREVIOUS... SHOWER CHANCES WILL INCREASE FROM WEST TO EAST AHEAD OF A SHORTWAVE TROUGH THAT REACHES THE AREA LATE THIS AFTERNOON. THINK A SLOWER APPROACH TO BEGINNING THE SHOWERS IS THE WAY TO GO AS THE MOISTURE ASSOCIATED WITH THE UPPER LEVEL WAVE WILL BE RUNNING INTO A VERY DRY ATMOSPHERE. SHOWERS WILL OVERSPREAD THE ENTIRE AREA THIS AFTERNOON AS THE WAVE MOVES THROUGH. WITH THE CLOUDS AND SHOWERS...TEMPERATURES WILL BE A BIT BELOW SEASONABLE LEVELS. SHOWERS CONTINUE OVERNIGHT AND INTO FRIDAY MORNING AS THE SURFACE BOUNDARY SLOWLY MOVES THROUGH THE REGION. && .SHORT TERM /FRIDAY THROUGH SATURDAY/... UPPER LEVEL SUPPORT WILL QUICKLY EXIT THE AREA...SO EXPECT THE SHOWERS TO RAP UP IN THE EAST FRIDAY MORNING. NO REAL DISCERNIBLE COLD ADVECTION IS EXPECTED...SO TEMPERATURES WILL BE ABLE TO REBOUND BACK TO...IF NOT WARMER THAN SEASONAL AVERAGES FRIDAY AFTERNOON. BROAD SURFACE HIGH AND UPPER LEVEL RIDGE WILL BUILD INTO THE OHIO VALLEY SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... MODELS STILL SHOWING A LARGE AND SLOW MOVING SYSTEM THAT WILL BRING AN EXTENDED PERIOD OF SHOWERS BEGINNING SUNDAY AND CONTINUING INTO EARLY TUESDAY. DRY AND SEASONABLE WEATHER WILL RETURN BEHIND THIS SYSTEM. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... VFR CONDITIONS WILL VERY SLOWLY GIVE WAY TO LOCAL MVFR CONDITIONS IN SCATTERED SHOWERS AS THEY ENCROACH ON THE REGION ESPECIALLY THIS AFTERNOON. CONFIDENCE IS LOW ON THE TIMES OF THE LOW DETERIORATION OF CIGS...HOWEVER VIRGA SHOULD GRADUALLY TURN INTO LIGHT RAIN AS HIGHER DEWPOINTS ENCROACH. INCREASING ESE TURNING SOUTH WINDS SHOULD PRECLUDE VISIBLITY RESTRICTIONS...HOWEVER CIGS WILL TREND AT LEAST CLOSE TO IFR BY TONIGHT AS DEEPER MOISTURE SLOWLY ENTERS THE REGION.FRIES .OUTLOOK.../TUESDAY NIGHT THROUGH SUNDAY/... THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH THE APPROACH OF LOW PRESSURE ON SUNDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
752 AM EDT THU APR 16 2015 .SYNOPSIS... A WEAK UPPER LEVEL DISTURBANCE AND TRAILING COLD FRONT WILL BRING SHOWERS TODAY THROUGH FRIDAY MORNING. A DRY AND COMFORTABLE START TO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... NO CHANGES NEEDED TO EARLY MORNING UPDATE PREVIOUS... SHOWER CHANCES WILL INCREASE FROM WEST TO EAST THIS MORNING AHEAD OF A SHORTWAVE TROUGH THAT REACHES THE AREA LATE THIS AFTERNOON. THINK A SLOWER APPROACH TO BEGINNING THE SHOWERS IS THE WAY TO GO AS THE MOISTURE ASSOCIATED WITH THE UPPER LEVEL WAVE WILL BE RUNNING INTO A VERY DRY ATMOSPHERE. SHOWERS WILL OVERSPREAD THE ENTIRE AREA THIS AFTERNOON AS THE WAVE MOVES THROUGH. WITH THE CLOUDS AND SHOWERS...TEMPERATURES WILL BE A BIT BELOW SEASONABLE LEVELS. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... SHOWERS CONTINUE OVERNIGHT AND INTO FRIDAY MORNING AS THE SURFACE BOUNDARY SLOWLY MOVES THROUGH THE REGION. UPPER LEVEL SUPPORT WILL QUICKLY EXIT THE AREA...SO EXPECT THE SHOWERS TO RAP UP IN THE EAST FRIDAY MORNING. NO REAL DISCERNIBLE COLD ADVECTION IS EXPECTED...SO TEMPERATURES WILL BE ABLE TO REBOUND BACK TO...IF NOT WARMER THAN SEASONAL AVERAGES FRIDAY AFTERNOON. BROAD SURFACE HIGH AND UPPER LEVEL RIDGE WILL BUILD INTO THE OHIO VALLEY SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... MODELS STILL SHOWING A LARGE AND SLOW MOVING SYSTEM THAT WILL BRING AN EXTENDED PERIOD OF SHOWERS BEGINNING SUNDAY AND CONTINUING INTO EARLY TUESDAY. DRY AND SEASONABLE WEATHER WILL RETURN BEHIND THIS SYSTEM. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... VFR CONDITIONS WILL VERY SLOWLY GIVE WAY TO LOCAL MVFR CONDITIONS IN SCATTERED SHOWERS AS THEY ENCROACH ON THE REGION ESPECIALLY THIS AFTERNOON. CONFIDENCE IS LOW ON THE TIMES OF THE LOW DETERIORATION OF CIGS...HOWEVER VIRGA SHOULD GRADUALLY TURN INTO LIGHT RAIN AS HIGHER DEWPOINTS ENCROACH. INCREASING ESE TURNING SOUTH WINDS SHOULD PRECLUDE VISIBLITY RESTRICTIONS...HOWEVER CIGS WILL TREND AT LEAST CLOSE TO IFR BY TONIGHT AS DEEPER MOISTURE SLOWLY ENTERS THE REGION.FRIES .OUTLOOK.../TUESDAY NIGHT THROUGH SUNDAY/... THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH THE APPROACH OF LOW PRESSURE ON SUNDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
620 AM EDT THU APR 16 2015 .SYNOPSIS... A WEAK UPPER LEVEL DISTURBANCE AND TRAILING COLD FRONT WILL BRING SHOWERS TODAY THROUGH FRIDAY MORNING. A DRY AND COMFORTABLE START TO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SHOWER CHANCES WILL INCREASE FROM WEST TO EAST THIS MORNING AHEAD OF A SHORTWAVE TROUGH THAT REACHES THE AREA LATE THIS AFTERNOON. STILL SEEING SOME TIMING DIFFERENCES IN MODEL SOLUTIONS AS THE MOISTURE ASSOCIATED WITH THE UPPER LEVEL WAVE WILL BE RUNNING INTO A VERY DRY ATMOSPHERE. THINK A SLOWER APPROACH TO BEGINNING THE SHOWERS IS THE WAY TO GO. SHOWERS WILL OVERSPREAD THE ENTIRE AREA THIS AFTERNOON AS THE WAVE MOVES THROUGH. WITH THE CLOUDS AND SHOWERS...TEMPERATURES WILL BE A BIT BELOW SEASONABLE LEVELS. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... SHOWERS CONTINUE OVERNIGHT AND INTO FRIDAY MORNING AS THE SURFACE BOUNDARY SLOWLY MOVES THROUGH THE REGION. UPPER LEVEL SUPPORT WILL QUICKLY EXIT THE AREA...SO EXPECT THE SHOWERS TO RAP UP IN THE EAST FRIDAY MORNING. NO REAL DISCERNIBLE COLD ADVECTION IS EXPECTED...SO TEMPERATURES WILL BE ABLE TO REBOUND BACK TO...IF NOT WARMER THAN SEASONAL AVERAGES FRIDAY AFTERNOON. BROAD SURFACE HIGH AND UPPER LEVEL RIDGE WILL BUILD INTO THE OHIO VALLEY SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... MODELS STILL SHOWING A LARGE AND SLOW MOVING SYSTEM THAT WILL BRING AN EXTENDED PERIOD OF SHOWERS BEGINNING SUNDAY AND CONTINUING INTO EARLY TUESDAY. DRY AND SEASONABLE WEATHER WILL RETURN BEHIND THIS SYSTEM. && .AVIATION /10Z THURSDAY THROUGH MONDAY/... VFR CONDITIONS WILL VERY SLOWLY GIVE WAY TO LOCAL MVFR CONDITIONS IN SCATTERED SHOWERS AS THEY ENCROACH ON THE REGION ESPECIALLY THIS AFTERNOON. CONFIDENCE IS LOW ON THE TIMES OF THE LOW DETERIORATION OF CIGS...HOWEVER VIRGA SHOULD GRADUALLY TURN INTO LIGHT RAIN AS HIGHER DEWPOINTS ENCROACH. INCREASING ESE TURNING SOUTH WINDS SHOULD PRECLUDE VISIBLITY RESTRICTIONS...HOWEVER CIGS WILL TREND AT LEAST CLOSE TO IFR BY TONIGHT AS DEEPER MOSITURE SLOWLY ENTERS THE REGION. FRIES .OUTLOOK.../TUESDAY NIGHT THROUGH SUNDAY/... THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH THE APPROACH OF LOW PRESSURE ON SUNDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
405 AM EDT THU APR 16 2015 .SYNOPSIS... A WEAK UPPER LEVEL DISTURBANCE AND TRAILING COLD FRONT WILL BRING SHOWERS TODAY THROUGH FRIDAY MORNING. A DRY AND COMFORTABLE START TO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SHOWER CHANCES WILL INCREASE FROM WEST TO EAST THIS MORNING AHEAD OF A SHORTWAVE TROUGH THAT REACHES THE AREA LATE THIS AFTERNOON. STILL SEEING SOME TIMING DIFFERENCES IN MODEL SOLUTIONS AS THE MOISTURE ASSOCIATED WITH THE UPPER LEVEL WAVE WILL BE RUNNING INTO A VERY DRY ATMOSPHERE. THINK A SLOWER APPROACH TO BEGINNING THE SHOWERS IS THE WAY TO GO. SHOWERS WILL OVERSPREAD THE ENTIRE AREA THIS AFTERNOON AS THE WAVE MOVES THROUGH. WITH THE CLOUDS AND SHOWERS...TEMPERATURES WILL BE A BIT BELOW SEASONABLE LEVELS. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... SHOWERS CONTINUE OVERNIGHT AND INTO FRIDAY MORNING AS THE SURFACE BOUNDARY SLOWLY MOVES THROUGH THE REGION. UPPER LEVEL SUPPORT WILL QUICKLY EXIT THE AREA...SO EXPECT THE SHOWERS TO RAP UP IN THE EAST FRIDAY MORNING. NO REAL DISCERNIBLE COLD ADVECTION IS EXPECTED...SO TEMPERATURES WILL BE ABLE TO REBOUND BACK TO...IF NOT WARMER THAN SEASONAL AVERAGES FRIDAY AFTERNOON. BROAD SURFACE HIGH AND UPPER LEVEL RIDGE WILL BUILD INTO THE OHIO VALLEY SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... MODELS STILL SHOWING A LARGE AND SLOW MOVING SYSTEM THAT WILL BRING AN EXTENDED PERIOD OF SHOWERS BEGINNING SUNDAY AND CONTINUING INTO EARLY TUESDAY. DRY AND SEASONABLE WEATHER WILL RETURN BEHIND THIS SYSTEM. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... VFR CONDITIONS WILL CONTINUE OVERNIGHT. TERMINALS MAY SEE MVFR CIG RESTRICTIONS BY TOMORROW EVENING WITH SCATTERED SHOWERS ACROSS THE REGION. .OUTLOOK.../TUESDAY NIGHT THROUGH SUNDAY/... THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH THE APPROACH OF LOW PRESSURE ON SUNDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
105 AM EDT THU APR 16 2015 .SYNOPSIS... A WEAK UPPER LEVEL DISTURBANCE AND TRAILING COLD FRONT WILL BRING SHOWERS TODAY THROUGH FRIDAY MORNING. A DRY AND COMFORTABLE START TO THE WEEKEND. && .NEAR TERM /THROUGH TODAY/... OVERNIGHT PERIOD IN GOOD SHAPE. JUST MADE MINOR ADJUSTMENTS TO THE ONSET OF POPS AS DAWN APPROACHES. TEMPERATURES HAVE BEEN NUDGED TOWARD THE LATEST LAMP NUMBERS. SHOWER CHANCES WILL INCREASE FROM WEST TO EAST THIS MORNING AHEAD OF A SHORTWAVE TROUGH THAT REACHES THE AREA LATE THIS AFTERNOON. STILL SEEING SOME TIMING DIFFERENCES IN MODEL SOLUTIONS AS THE MOISTURE ASSOCIATED WITH THE UPPER LEVEL WAVE WILL BE RUNNING INTO A VERY DRY ATMOSPHERE. THINK A SLOWER APPROACH TO BEGINNING SHOWERS IS THE WAY TO GO. SHOWERS WILL OVERSPREAD THE ENTIRE AREA THIS AFTERNOON AS THE WAVE MOVES THROUGH. WITH THE CLOUDS AND SHOWERS...TEMPERATURES WILL BE A BIT BELOW SEASONABLE LEVELS. && .SHORT TERM /TONIGHT THROUGH SATURDAY/... SHOWERS CONTINUE OVERNIGHT AND INTO FRIDAY MORNING AS THE SURFACE BOUNDARY SLOWLY MOVES THROUGH THE REGION. UPPER LEVEL SUPPORT WILL QUICKLY EXIT THE AREA...SO EXPECT THE SHOWERS TO RAP UP IN THE EAST FRIDAY MORNING. NO REAL DISCERNIBLE COLD ADVECTION IS EXPECTED...SO TEMPERATURES WILL BE ABLE TO REBOUND BACK TO...IF NOT WARMER THAN SEASONAL AVERAGES FRIDAY AFTERNOON. BROAD SURFACE HIGH AND UPPER LEVEL RIDGE WILL BUILD INTO THE OHIO VALLEY SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... MODELS STILL SHOWING A LARGE AND SLOW MOVING SYSTEM THAT WILL BRING AN EXTENDED PERIOD OF SHOWERS BEGINNING SUNDAY AND CONTINUING INTO EARLY TUESDAY. DRY AND SEASONABLE WEATHER WILL RETURN BEHIND THIS SYSTEM. && .AVIATION /05Z THURSDAY THROUGH MONDAY/... VFR CONDITIONS WILL CONTINUE OVERNIGHT. TERMINALS MAY SEE MVFR CIG RESTRICTIONS BY TOMORROW EVENING WITH SCATTERED SHOWERS ACROSS THE REGION. .OUTLOOK.../TUESDAY NIGHT THROUGH SUNDAY/... THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH THE APPROACH OF LOW PRESSURE ON SUNDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
128 PM EDT THU APR 16 2015 .UPDATE... ISSUED AT 657 AM EDT THU APR 16 2015 DECIDED TO PUT SPRINKLES INTO FORECAST OVER EASTERN CWA /ISQ-ERY/ MID MORNING INTO EARLY AFTN AS BAND OF SHOWERS OVER LOWER MICHIGAN CONTINUES TO LIFT NORTHWARD. EVEN THOUGH SHRA WILL BE RUNNING INTO THE DRY AIRMASS OVER AREA AS SEEN ON 00Z APX AND DTX RAOBS...THINK ENOUGH FOCUS FM SHORTWAVE AND MOISTURE TRANSPORT AT H85-H7 IS GOING TO END UP STRONG/PERSISTENT ENOUGH TO OUTWEIGH THE LOW-LEVEL DRY AIR. VARIOUS HIGH RES MODELS AND THE 06Z/07Z HRRR REFLECTIVITY OUTPUT POINT TO AT LEAST A BRIEF PERIOD OF LGT RAIN/SPRINKLES. BEEFED UP SKY COVER SOME MORE AS WELL. OTHER THAN TWEAKS FOR VERY SHORT TERM TEMP/DWPNT TRENDS...NO OTHER CHANGES WERE NEEDED TO FORECAST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 435 AM EDT THU APR 16 2015 SHORTWAVE RIDGING PERSISTS TODAY BTWN NORTHERN STREAM SHORTWAVE THAT CROSSES MANITOBA/NORTHERN ONTARIO AND CUTOFF LOW OVER FOUR CORNERS OF SW CONUS. WEAK AREAS OF VORTICITY LIFTING INTO THE RIDGE BRINGING A PUSH OF MID-LEVEL MOISTURE ADVECTION AROUND H7. DECENT AREA OF SHRA IS LIFTING NORTHWARD OVER WESTERN LOWER MICHIGAN ON NORTH EDGE OF MOISTURE TRANSPORT AT H85-H7 AND THIS COULD BRING VIRGA OR A FEW SPRINKLES TO EASTERN CWA...POSSIBLY AS FAR WEST AS KESC PER HRRR MODEL LATE MORNING INTO EARLY AFTN. ELSEWHERE WILL CERTAINLY BE MORE CLOUDS THAN LAST COUPLE DAYS AS CIRRUS AND MORE PRONOUNCED AREA OF AC/AS OVER MN SLIDES IN FOR THE AFTN. EVEN SO THOUGH...WARM START SHOULD STILL ALLOW MAX TEMPS TO REACH WELL INTO THE 60S. RH VALUES A BIT HIGHER THAN BONE DRY CONDITIONS SEEN TUE/WED WHERE RH BOTTOMED OUT AROUND 10 PCT OVER INTERIOR WEST. FOR TODAY IN THOSE AREAS... EXPECT MAINLY 18-25 PCT RANGE AT THE LOW-END. WINDS LESS THAN 10 MPH MOST AREAS WITH LOCAL LAKE BREEZES CNTRL. OVERALL APPEARS TO NOT BE AS MUCH OF ISSUE WITH FIRE WEATHER TODAY COMPARED TO TUE OR WED. NORTHERN STREAM SHORTWAVE CROSSES NORTHERN ONTARIO TONIGHT WITH TAIL OF ENHANCED CLOUD GRAZING CWA...ALONG WITH THE PASSAGE OF SFC TROUGH...MORE OF A WIND SHIFT FM SW TO NW LATE TONIGHT. SINCE 1000- 700MB LAPSE RATES ARE HIGH...OVER 7C/KM BY LATE AFTN...AND FORCING IS MOVING THROUGH WITH SUFFICIENT MOISTURE ALOFT...THINK THERE IS A CHANCE OF SPRINKLES/VIRGA THIS EVENING AS THE FORCING MOVES THROUGH...PERHAPS SIMILAR TO WHAT OCCURRED MON AFTN/EVENING. THAT SAID...WINDS IN MIXED LAYER THIS EVENING DO INCREASE BY 03Z WITH 25- 30 KTS AT TOP PARTS OF THE MIXED LAYER. SO...FEASIBLE THAT GUSTY WINDS COULD OCCUR IN THE VCNTY OF ANY WELL DEVELOPED CU OR VIRGA/SPRINKLES. ALL FORCING IS OUT OF HERE BY MIDNIGHT AND SCT-BKN CLOUDS SHOULD EXIT OVERNIGHT. SKIES WILL BE MAINLY CLEAR BY DAYBREAK ON FRIDAY. LOWS TONIGHT SHOULD REMAIN ABOVE FREEZING ALL AREAS GIVEN THE WINDS AND CLOUDS MOST OF THE NIGHT AND LACK OF COLD AIR BEHIND THE TROUGH. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 436 PM EDT WED APR 15 2015 AFTER A QUIET AND GENERALLY WARM REST OF THIS WEEK...SIGNIFICANT AMPLIFICATION OF THE FLOW IS EXPECTED THIS WEEKEND AND EARLY NEXT WEEK AS A SHARP RIDGE BUILDS THRU WRN CANADA. THIS WILL FORCE A DEEP TROF TO DEVELOP DOWNSTREAM WITH AXIS ROUGHLY OVER THE MISSISSIPPI VALLEY BY MON. TYPICAL FOR THIS TIME OF YEAR...CLOSED LOWS FREQUENTLY DEVELOP...AND THIS TROF WILL QUICKLY EVOLVE IN THAT DIRECTION AS MAJORITY OF GUIDANCE INCLUDING GFS/GEM ENSEMBLES SHOW EVOLUTION INTO A LARGE/COLD MID-LEVEL LOW OVER THE VICINITY OF THE UPPER GREAT LAKES. MAY BE DIFFICULT TO DISLODGE THE LOW NEXT WEEK ONCE IT DEVELOPS. SO...AFTER A WARM/DRY REST OF THIS WEEK...NEXT WEEK WILL BE COLD AND GENERALLY UNSETTLED WITH PERIODIC CHANCES OF SNOW AND RAIN SHOWERS. FROM A PCPN PERSPECTIVE...THE BIGGEST CHALLENGE IS HOW THE SHARP PATTERN AMPLIFICATION INTERACTS WITH WHAT IS CURRENTLY AN IMPRESSIVE LOOKING TROF CLOSING OFF OVER UT/CO. MEDIUM RANGE GUIDANCE TODAY IS IN MUCH BETTER AGREEMENT IN SHOWING THE AMPLIFICATION OF THE FLOW PICKING UP THE MID-LEVEL LOW AND FORCING THE OPENED UP SYSTEM/REMNANT ENERGY NE INTO THE GREAT LAKES REGION. RANGE OF POSSIBILITIES STILL INCLUDE A SIGNIFICANT RAIN EVENT TO A RAIN CHANGING TO ACCUMULATING SNOW EVENT TO MINIMAL PCPN IF THE SRN ENERGY DOES NOT LIFT FAR ENOUGH N AND W WITHIN THE AMPLIFYING PATTERN. OPERATIONAL MEDIUM RANGE MODELS WEAKEN THE ENERGY DRAMATICALLY AS IT LIFTS NE (WILL BE INTERESTING TO SEE IF THAT ACTUALLY HAPPENS)...SO THE LOWEST PROBABILITY OUTCOME RIGHT NOW IS ONE THAT BRINGS A SIGNIFICANT PCPN PRODUCING SYSTEM WITH A PROMINENT DEFORMATION PCPN SHIELD INTO THE UPPER LAKES EARLY NEXT WEEK. THAT SAID...THERE HAVE BEEN AND THERE STILL ARE SOME GFS/GEM ENSEMBLES THAT DO SHOW SUCH A SCENARIO...SO IT CAN`T BE RULED OUT. BEGINNING THU NIGHT...TAIL END OF SHORTWAVE TRACKING FROM HUDSON BAY INTO QUEBEC WILL PASS ACROSS THE AREA THU NIGHT. FORCING FROM THE RIGHT ENTRANCE OF AN UPPER JET STREAK AND MAIN DEEP LAYER QVECTOR CONVERGENCE...WEAK AT THAT...PASS N OF THE AREA...SUPPORTING BEST CHC OF -SHRA N OF HERE. ACROSS UPPER MI...VERY WEAK FORCING/WEAK FRONTAL BOUNDARY AND WEAK MOISTURE TRANSPORT ALL SUGGEST PROSPECT OF ANY PCPN IS VERY LIMITED AS SHORTWAVE PASSES. THUS...WILL RETAIN DRY FCST FOR THU NIGHT. IN THE MAIN FLOW TO THE N...ANOTHER SHORTWAVE IS FCST TO TRACK FROM THE CANADIAN ROCKIES THU AFTN TO NRN ONTARIO FRI. MODELS HAVE TRENDED TO MUCH BETTER AGREEMENT ON THIS WAVE WITH GEM/GFS/NAM MOVING TO THE ECMWF SCENARIO WHICH HAS BEEN FARTHER N THAN THOSE MODELS FOR SEVERAL RUNS. WITH THE TRACK OF THE SHORTWAVE JUST N OF LAKE SUPERIOR...BEST FORCING AND POTENTIAL FOR PCPN WILL PASS BY TO THE N. REMOVED SCHC POPS FROM INHERITED FCST IN FAVOR OF DRY WEATHER. EXPECT HIGH TEMPS FRI IN THE 60S AWAY FROM LAKE MODERATION. A FEW SPOTS MAY REACH 70F. INTERIOR RH SHOULD FALL TO 25-30PCT... AND WINDS MAY BE A LITTLE GUSTY TO 15-20MPH AT TIMES...KEEPING FIRE WX A CONCERN. IN THE WAKE OF THE SHORTWAVE...HIGH PRES BUILDS INTO THE AREA FOR SAT. WITH THE HIGH ENDING UP OVER LAKE SUPERIOR IN THE AFTN...IT WILL BE A MUCH COOLER DAY NEAR LAKE SUPERIOR...ESPECIALLY FROM THE KEWEENAW EASTWARD. RIGHT ALONG THE SHORE...TEMPS SHOULDN`T GET OUT OF THE 30S. IN THE INTERIOR W HALF...TEMPS SHOULD RISE TO AROUND 60F UNDER SUNNY SKIES. SUN/MON...WILL CONTINUE TO UTILIZE A CONSENSUS APPROACH OF CURRENT AND RECENT MEDIUM RANGE GUIDANCE FOR THE EVOLUTION OF THE SRN ROCKIES ENERGY INTO THE GREAT LAKES AHEAD OF THE TROF AMPLIFICATION OCCURRING INTO THE PLAINS/MISSISSIPPI VALLEY. IT APPEARS THERE MAY END UP BEING TWO SURGES OF PCPN OR SFC LOW PRES WAVES...ONE ASSOCIATED WITH LEAD ENERGY SWINGING UP FROM MEXICO AND A SECOND ASSOCIATED WITH THE MAIN REMNANT OF THE ROCKIES MID LEVEL LOW. LATEST GUIDANCE SUGGESTS RAIN WILL BEGIN SPREADING INTO UPPER MI SUN AND THEN CONTINUE INTO MON. AIR MASS SHOULD COOL ENOUGH TO ALLOW SOME SNOW TO BEGIN MIXING WITH THE RAIN OVER THE W ON MON. PTYPE WILL THEN BECOME ALL SNOW ACROSS THE FCST AREA MON NIGHT FOR WHATEVER PCPN LINGERS. TUE/WED...LARGE/COLD MID-LEVEL LOW WILL HAVE DEVELOPED AND WILL BE CENTERED IN THE VCNTY OF THE UPPER GREAT LAKES. COLD AIR ALOFT/SPRING DAYTIME HEATING AND POTENTIAL OF SHORTWAVES ROTATING THRU THE AREA WITHIN THE LARGE MID-LEVEL LOW CIRCULATION SUGGEST AT LEAST SCT SHOWERY PCPN (MOSTLY SNOW BUT SOME RAIN AS WELL DURING PEAK HEATING) BOTH DAYS WITH BEST COVERAGE IN THE AFTN INLAND FROM LAKE SUPERIOR WHERE HEATING IS BEST. HIGH TEMPS BOTH DAYS SHOULD BE IN THE MID 30S TO MID 40S...WARMEST SCNTRL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 125 PM EDT THU APR 16 2015 VFR CONDITIONS WILL CONTINUE FOR THIS FORECAST PERIOD. IT IS POSSIBLE THERE COULD BE A LIGHT SHOWER OR SPRINKLE AROUND EARLY THIS EVENING AHEAD OF THE FRONT. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 435 AM EDT THU APR 16 2015 NO WIDESPREAD GALES ARE EXPECTED THROUGH THE FORECAST PERIOD...BUT THERE WILL BE A FEW PERIODS OF STRONGER WINDS STARTING THIS WEEKEND. WINDS EXPECTED TO REMAIN AT OR BLO 20 KTS THROUGH FRIDAY NIGHT AS PRESSURE GRADIENT IS WEAK. HIGH PRESSURE MOVING ACROSS ON SATURDAY WITH LOW PRESSURE FOLLOWING OVER SCNTRL CANADA ON SUNDAY WILL RESULT IN SETUP FOR STRONGER EAST-NORTHEAST WINDS TO 30 KTS OVER WESTERN LK SUPERIOR SATURDAY AND SATURDAY NIGHT. STRONGEST WINDS WILL BE TOWARD HEAD OF LK SUPERIOR NEAR DULUTH AND SUPERIOR. BY SUNDAY...AS THE LOW PRESSURE SYSTEM APPROACHES...SOUTHEAST WINDS TO 30 KTS WILL BE POSSIBLE OVER EASTERN HALF OF LK SUPERIOR WHILE WINDS DIMINISH IN THE WEST. THE LOW CROSSES THE UPPER GREAT LAKES BY MONDAY WHILE MERGING WITH ANOTHER LOW LIFTING IN FM THE CENTRAL PLAINS. EXPECT WEST WINDS UP TO 30 KTS OVER MUCH OF THE LAKE LATER MONDAY INTO TUESDAY IN WAKE OF THIS COMBINED LOW AS IT MOVES TO THE LOWER GREAT LAKES. && .HYDROLOGY... ISSUED AT 332 PM EDT WED APR 15 2015 SEEMS THAT WITHOUT ANY SIGNIFICANT ADDITIONAL PRECIPITATION ADDED TO THE ONGOING SNOWMELT...AT LEAST FOR THE REST OF THIS WEEK...MAINLY LOOKING AT A FEW BANKFULL ISSUES ON SOME RIVERS WITH CONTINUATION OF LOW-END ADVISORIES. BELOW NORMAL TEMPERATURES ARE EXPECTED MONDAY THROUGH MUCH OF NEXT WEEK...WHICH WILL LIMIT MELTING OF ANY REMAINING SNOW PACK AND REDUCE RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SHORT TERM...JLA LONG TERM...ROLFSON AVIATION...TITUS MARINE...JLA HYDROLOGY...TITUS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1205 PM EDT THU APR 16 2015 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 310 AM EDT THU APR 16 2015 LIGHT RAIN IS LIKELY TODAY ACROSS MUCH OF SOUTHWEST LOWER MICHIGAN AS WEAK LOW PRESSURE MOVES NORTH FROM THE GULF. THE SHOWERS WILL DIMINISH TONIGHT LEADING TO A DRY FRIDAY AND SATURDAY. RAIN IS BACK IN THE PICTURE LATE IN THE WEEKEND AND EARLY NEXT WEEK AS A STRONGER LOW MOVES EAST FROM THE PLAINS ACROSS THE GREAT LAKES. TODAY WILL BE A BIT COOLER THAN WEDNESDAY; WE/LL SEE HIGHS IN THE 50S. TEMPERATURES WILL CLIMB TO AROUND 70 FRIDAY AND SATURDAY BEFORE COOLER WEATHER DEVELOPS EARLY NEXT WEEK. MUCH OF NEXT WEEK WILL SEE HIGHS ONLY AROUND 50. && .UPDATE... ISSUED AT 856 AM EDT THU APR 16 2015 I DID A QUICK UPDATE TO THE POP AND WEATHER GRIDS TO BETTER REFLECT THE CURRENT RADAR TRENDS. THAT MEANS I INCREASED THE POP TO NEAR 100 PCT OVER OUR NW CWA AND I HAVE AN AREA OF LOW POP SOUTHWEST OF GRR (IT IS REALLY THERE) THAT MOVES NORTH WITH TIME. THE ENTIRE AREA OF SHOWERS SHOULD BE MOSTLY OUT OF OUR CWA BY MID AFTERNOON AS DRIER AIR MOVES IN AT MID LEVELS. THIS IDEA IS MOSTLY BASED ON USING THE RAP MODEL LIFT IN THE DGZ WHERE THE AIR IN THAT LAYER IS SATURATED. AT 8 AM THE AREA OF BEST LIFT IS NEAR AND WEST OF US-131. BY 2 PM IT IS MOSTLY EAST OF I-75 BUT THERE IS A SMALL AREA OF STRONG LIFT JUST SOUTH OF GRR AT THAT TIME WHICH LIFTS TO NEAR LANSING BY 5 PM. THAT WILL HAVE TO BE WATCHED TO SEE OF AN AREA OF SIGNIFICANT SHOWERS DOES DEVELOP THERE. I STILL EXPECT NO THUNDERSTORM ACTIVITY TODAY. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 310 AM EDT THU APR 16 2015 FORECAST CONCERNS DEAL WITH PCPN TRENDS TODAY. OVERALL...THE FORECAST IS LARGELY ON TRACK ALTHOUGH QPF HAS BEEN TRIMMED A BIT. 00Z SOUNDING AT DTX WAS EXTREMELY DRY BELOW 450 MB AND EXPLAINS WHY WE HAVEN/T SEEN MUCH RAIN AT THE SFC DESPITE ECHOS ACROSS THE LAKE SHORE. THE SFC WAVE OF LOW PRESSURE TO THE SOUTH WILL MOVE OVER THE CWA TODAY AND WE SHOULD SEE THE LOWER LEVELS OF THE ATM MOISTEN AND RAIN TO DEVELOP. KGRR-88D SHOWS ECHO INTENSITY INCREASING A BIT AS PCPN CONTINUES TO MOVE NORTH FROM INDIANA. SHORT RANGE NWP SHOWED THE AREA OF THETA-E DECREASING WITH HEIGHT REMAINING SOUTH OF THE CWA SO WE OPTED TO GO WITH NO THUNDER IN THE GRIDS TODAY. PCPN WILL BEGIN TO MOVE EAST THIS AFTERNOON AND END EARLY IN THE EVENING. THIS WILL LEAD TO A COUPLE OF DRY DAYS FRIDAY AND SATURDAY AS HIGH PRESSURE NOSES IN FROM ONTARIO. TEMPS WILL BE HELD DOWN A BIT BY THE SHOWERS TODAY AND WE`LL GO WITH HIGHS IN THE MID TO UPPER 50S. UPPER HEIGHT RISES ASSOCIATED WITH THE RIDGE WILL RESULT IN TEMPS AROUND 10 DEGREES WARMER FRIDAY AND SATURDAY. .LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 310 AM EDT THU APR 16 2015 MODEL GUIDANCE REMAINS CONSISTENT IN SHOWING RAIN MOVING IN ON SUNDAY WITH THE BEST CHANCE FOR WET WEATHER SUNDAY AFTERNOON AND EVENING AS A SFC LOW AND UPPER TROUGH AXIS MOVES OVER LOWER MICHIGAN. THE LOW CUTS OFF AND BECOMES VERTICALLY STACKED NORTH OF LAKE SUPERIOR ON MONDAY WITH VORT ENERGY ROTATING THROUGH LOWER MICHIGAN ON TUESDAY AND WEDNESDAY. GIVEN WET BULB ZERO HEIGHTS CRASHING TO NEAR THE SFC...DO NOT BE SURPRISED TO SEE SOME SNOW ACROSS AT LEAST THE NORTHERN ZONES TUESDAY THROUGH WEDNESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY) ISSUED AT 1205 PM EDT THU APR 16 2015 A MIX OF MVFR AND VFR CONDITIONS WILL CONTINUE THIS AFTERNOON DUE TO AREAS OF LOW CLOUD COVER. LINGERING LIGHT RAIN SHOWERS AND SPRINKLES WILL GRADUALLY TAPER OFF THIS AFTERNOON. CONDITIONS SHOULD IMPROVE TO MAINLY VFR THIS EVENING BUT THE COMBINATION OF PARTIAL CLEARING AND LIGHT WINDS IN CONJUNCTION WITH LINGERING BOUNDARY LAYER MOISTURE FROM RAINFALL TODAY WILL RESULT IN POTENTIAL FOR PATCHY FOG TO DEVELOP OVERNIGHT. ANY FOG SHOULD DISSIPATE BY MID MORNING FRIDAY WITH VFR CONDITIONS TO FOLLOW FOR THE REST OF THE DAY. && .MARINE... ISSUED AT 310 AM EDT THU APR 16 2015 EAST WINDS 5 TO 15 KNOTS WILL NOT BE HAZARDOUS TO SMALL CRAFT TODAY. && .HYDROLOGY... ISSUED AT 1123 AM EDT THU APR 16 2015 THE LONE ADVISORY AT MAPLE RAPIDS CONTINUES TO SHOW IMPROVEMENT. LIGHTER PRECIPITATION TODAY SHOULD NOT HAVE MUCH OF AN AFFECT ON THE DROP THAT IS BEING EXPERIENCED. WE SHOULD SEE LEVELS DROP BELOW ADVISORY CRITERIA LATE THIS EVENING. BEYOND TWO DRY DAYS...FRIDAY AND SATURDAY...THE PATTERN GETS A BIT ACTIVE AGAIN. WE COULD SEE SOME BENEFICIAL PRECIPITATION BETWEEN SUNDAY AND TUESDAY. TOTAL AMOUNTS OVER THE NEXT 7 DAYS ARE NOT TOO HEAVY. SOME MINOR FLUCTUATIONS MAY RESULT ON AREA RIVERS EARLY NEXT WEEK...BUT AT THIS POINT I DO NOT SEE ANY REAL CAUSE FOR CONCERN THROUGH THE PERIOD. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...04 SHORT TERM...04 LONG TERM...OSTUNO AVIATION...LAURENS HYDROLOGY...JAM MARINE...04
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1123 AM EDT THU APR 16 2015 LATEST UPDATE... HYDRO .SYNOPSIS... ISSUED AT 310 AM EDT THU APR 16 2015 LIGHT RAIN IS LIKELY TODAY ACROSS MUCH OF SOUTHWEST LOWER MICHIGAN AS WEAK LOW PRESSURE MOVES NORTH FROM THE GULF. THE SHOWERS WILL DIMINISH TONIGHT LEADING TO A DRY FRIDAY AND SATURDAY. RAIN IS BACK IN THE PICTURE LATE IN THE WEEKEND AND EARLY NEXT WEEK AS A STRONGER LOW MOVES EAST FROM THE PLAINS ACROSS THE GREAT LAKES. TODAY WILL BE A BIT COOLER THAN WEDNESDAY; WE/LL SEE HIGHS IN THE 50S. TEMPERATURES WILL CLIMB TO AROUND 70 FRIDAY AND SATURDAY BEFORE COOLER WEATHER DEVELOPS EARLY NEXT WEEK. MUCH OF NEXT WEEK WILL SEE HIGHS ONLY AROUND 50. && .UPDATE... ISSUED AT 856 AM EDT THU APR 16 2015 I DID A QUICK UPDATE TO THE POP AND WEATHER GRIDS TO BETTER REFLECT THE CURRENT RADAR TRENDS. THAT MEANS I INCREASED THE POP TO NEAR 100 PCT OVER OUR NW CWA AND I HAVE AN AREA OF LOW POP SOUTHWEST OF GRR (IT IS REALLY THERE) THAT MOVES NORTH WITH TIME. THE ENTIRE AREA OF SHOWERS SHOULD BE MOSTLY OUT OF OUR CWA BY MID AFTERNOON AS DRIER AIR MOVES IN AT MID LEVELS. THIS IDEA IS MOSTLY BASED ON USING THE RAP MODEL LIFT IN THE DGZ WHERE THE AIR IN THAT LAYER IS SATURATED. AT 8 AM THE AREA OF BEST LIFT IS NEAR AND WEST OF US-131. BY 2 PM IT IS MOSTLY EAST OF I-75 BUT THERE IS A SMALL AREA OF STRONG LIFT JUST SOUTH OF GRR AT THAT TIME WHICH LIFTS TO NEAR LANSING BY 5 PM. THAT WILL HAVE TO BE WATCHED TO SEE OF AN AREA OF SIGNIFICANT SHOWERS DOES DEVELOP THERE. I STILL EXPECT NO THUNDERSTORM ACTIVITY TODAY. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 310 AM EDT THU APR 16 2015 FORECAST CONCERNS DEAL WITH PCPN TRENDS TODAY. OVERALL...THE FORECAST IS LARGELY ON TRACK ALTHOUGH QPF HAS BEEN TRIMMED A BIT. 00Z SOUNDING AT DTX WAS EXTREMELY DRY BELOW 450 MB AND EXPLAINS WHY WE HAVEN/T SEEN MUCH RAIN AT THE SFC DESPITE ECHOS ACROSS THE LAKE SHORE. THE SFC WAVE OF LOW PRESSURE TO THE SOUTH WILL MOVE OVER THE CWA TODAY AND WE SHOULD SEE THE LOWER LEVELS OF THE ATM MOISTEN AND RAIN TO DEVELOP. KGRR-88D SHOWS ECHO INTENSITY INCREASING A BIT AS PCPN CONTINUES TO MOVE NORTH FROM INDIANA. SHORT RANGE NWP SHOWED THE AREA OF THETA-E DECREASING WITH HEIGHT REMAINING SOUTH OF THE CWA SO WE OPTED TO GO WITH NO THUNDER IN THE GRIDS TODAY. PCPN WILL BEGIN TO MOVE EAST THIS AFTERNOON AND END EARLY IN THE EVENING. THIS WILL LEAD TO A COUPLE OF DRY DAYS FRIDAY AND SATURDAY AS HIGH PRESSURE NOSES IN FROM ONTARIO. TEMPS WILL BE HELD DOWN A BIT BY THE SHOWERS TODAY AND WE`LL GO WITH HIGHS IN THE MID TO UPPER 50S. UPPER HEIGHT RISES ASSOCIATED WITH THE RIDGE WILL RESULT IN TEMPS AROUND 10 DEGREES WARMER FRIDAY AND SATURDAY. .LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 310 AM EDT THU APR 16 2015 MODEL GUIDANCE REMAINS CONSISTENT IN SHOWING RAIN MOVING IN ON SUNDAY WITH THE BEST CHANCE FOR WET WEATHER SUNDAY AFTERNOON AND EVENING AS A SFC LOW AND UPPER TROUGH AXIS MOVES OVER LOWER MICHIGAN. THE LOW CUTS OFF AND BECOMES VERTICALLY STACKED NORTH OF LAKE SUPERIOR ON MONDAY WITH VORT ENERGY ROTATING THROUGH LOWER MICHIGAN ON TUESDAY AND WEDNESDAY. GIVEN WET BULB ZERO HEIGHTS CRASHING TO NEAR THE SFC...DO NOT BE SURPRISED TO SEE SOME SNOW ACROSS AT LEAST THE NORTHERN ZONES TUESDAY THROUGH WEDNESDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 736 AM EDT THU APR 16 2015 MVFR CONDITIONS WILL BECOME MORE WIDESPREAD TODAY AS SCATTERED SHOWERS CONTINUE BUT THERE SHOULD FEW IF ANY AREAS OF IFR THROUGH TONIGHT. WINDS WILL BE SOUTHEAST TODAY AOB 10 KNOTS THEN GO WEST BY THIS EVENING AND DECREASE TO ABOUT 5 KNOTS. && .MARINE... ISSUED AT 310 AM EDT THU APR 16 2015 EAST WINDS 5 TO 15 KNOTS WILL NOT BE HAZARDOUS TO SMALL CRAFT TODAY. && .HYDROLOGY... ISSUED AT 1123 AM EDT THU APR 16 2015 THE LONE ADVISORY AT MAPLE RAPIDS CONTINUES TO SHOW IMPROVEMENT. LIGHTER PRECIPITATION TODAY SHOULD NOT HAVE MUCH OF AN AFFECT ON THE DROP THAT IS BEING EXPERIENCED. WE SHOULD SEE LEVELS DROP BELOW ADVISORY CRITERIA LATE THIS EVENING. BEYOND TWO DRY DAYS...FRIDAY AND SATURDAY...THE PATTERN GETS A BIT ACTIVE AGAIN. WE COULD SEE SOME BENEFICIAL PRECIPITATION BETWEEN SUNDAY AND TUESDAY. TOTAL AMOUNTS OVER THE NEXT 7 DAYS ARE NOT TOO HEAVY. SOME MINOR FLUCTUATIONS MAY RESULT ON AREA RIVERS EARLY NEXT WEEK...BUT AT THIS POINT I DO NOT SEE ANY REAL CAUSE FOR CONCERN THROUGH THE PERIOD. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...04 SHORT TERM...04 LONG TERM...OSTUNO AVIATION...OSTUNO HYDROLOGY...JAM MARINE...04
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
856 AM EDT THU APR 16 2015 LATEST UPDATE... UPDATE .SYNOPSIS... ISSUED AT 310 AM EDT THU APR 16 2015 LIGHT RAIN IS LIKELY TODAY ACROSS MUCH OF SOUTHWEST LOWER MICHIGAN AS WEAK LOW PRESSURE MOVES NORTH FROM THE GULF. THE SHOWERS WILL DIMINISH TONIGHT LEADING TO A DRY FRIDAY AND SATURDAY. RAIN IS BACK IN THE PICTURE LATE IN THE WEEKEND AND EARLY NEXT WEEK AS A STRONGER LOW MOVES EAST FROM THE PLAINS ACROSS THE GREAT LAKES. TODAY WILL BE A BIT COOLER THAN WEDNESDAY; WE/LL SEE HIGHS IN THE 50S. TEMPERATURES WILL CLIMB TO AROUND 70 FRIDAY AND SATURDAY BEFORE COOLER WEATHER DEVELOPS EARLY NEXT WEEK. MUCH OF NEXT WEEK WILL SEE HIGHS ONLY AROUND 50. && .UPDATE... ISSUED AT 856 AM EDT THU APR 16 2015 I DID A QUICK UPDATE TO THE POP AND WEATHER GRIDS TO BETTER REFLECT THE CURRENT RADAR TRENDS. THAT MEANS I INCREASED THE POP TO NEAR 100 PCT OVER OUR NW CWA AND I HAVE AN AREA OF LOW POP SOUTHWEST OF GRR (IT IS REALLY THERE) THAT MOVES NORTH WITH TIME. THE ENTIRE AREA OF SHOWERS SHOULD BE MOSTLY OUT OF OUR CWA BY MID AFTERNOON AS DRIER AIR MOVES IN AT MID LEVELS. THIS IDEA IS MOSTLY BASED ON USING THE RAP MODEL LIFT IN THE DGZ WHERE THE AIR IN THAT LAYER IS SATURATED. AT 8 AM THE AREA OF BEST LIFT IS NEAR AND WEST OF US-131. BY 2 PM IT IS MOSTLY EAST OF I-75 BUT THERE IS A SMALL AREA OF STRONG LIFT JUST SOUTH OF GRR AT THAT TIME WHICH LIFTS TO NEAR LANSING BY 5 PM. THAT WILL HAVE TO BE WATCHED TO SEE OF AN AREA OF SIGNIFICANT SHOWERS DOES DEVELOP THERE. I STILL EXPECT NO THUNDERSTORM ACTIVITY TODAY. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 310 AM EDT THU APR 16 2015 FORECAST CONCERNS DEAL WITH PCPN TRENDS TODAY. OVERALL...THE FORECAST IS LARGELY ON TRACK ALTHOUGH QPF HAS BEEN TRIMMED A BIT. 00Z SOUNDING AT DTX WAS EXTREMELY DRY BELOW 450 MB AND EXPLAINS WHY WE HAVEN/T SEEN MUCH RAIN AT THE SFC DESPITE ECHOS ACROSS THE LAKE SHORE. THE SFC WAVE OF LOW PRESSURE TO THE SOUTH WILL MOVE OVER THE CWA TODAY AND WE SHOULD SEE THE LOWER LEVELS OF THE ATM MOISTEN AND RAIN TO DEVELOP. KGRR-88D SHOWS ECHO INTENSITY INCREASING A BIT AS PCPN CONTINUES TO MOVE NORTH FROM INDIANA. SHORT RANGE NWP SHOWED THE AREA OF THETA-E DECREASING WITH HEIGHT REMAINING SOUTH OF THE CWA SO WE OPTED TO GO WITH NO THUNDER IN THE GRIDS TODAY. PCPN WILL BEGIN TO MOVE EAST THIS AFTERNOON AND END EARLY IN THE EVENING. THIS WILL LEAD TO A COUPLE OF DRY DAYS FRIDAY AND SATURDAY AS HIGH PRESSURE NOSES IN FROM ONTARIO. TEMPS WILL BE HELD DOWN A BIT BY THE SHOWERS TODAY AND WE`LL GO WITH HIGHS IN THE MID TO UPPER 50S. UPPER HEIGHT RISES ASSOCIATED WITH THE RIDGE WILL RESULT IN TEMPS AROUND 10 DEGREES WARMER FRIDAY AND SATURDAY. .LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 310 AM EDT THU APR 16 2015 MODEL GUIDANCE REMAINS CONSISTENT IN SHOWING RAIN MOVING IN ON SUNDAY WITH THE BEST CHANCE FOR WET WEATHER SUNDAY AFTERNOON AND EVENING AS A SFC LOW AND UPPER TROUGH AXIS MOVES OVER LOWER MICHIGAN. THE LOW CUTS OFF AND BECOMES VERTICALLY STACKED NORTH OF LAKE SUPERIOR ON MONDAY WITH VORT ENERGY ROTATING THROUGH LOWER MICHIGAN ON TUESDAY AND WEDNESDAY. GIVEN WET BULB ZERO HEIGHTS CRASHING TO NEAR THE SFC...DO NOT BE SURPRISED TO SEE SOME SNOW ACROSS AT LEAST THE NORTHERN ZONES TUESDAY THROUGH WEDNESDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 736 AM EDT THU APR 16 2015 MVFR CONDITIONS WILL BECOME MORE WIDESPREAD TODAY AS SCATTERED SHOWERS CONTINUE BUT THERE SHOULD FEW IF ANY AREAS OF IFR THROUGH TONIGHT. WINDS WILL BE SOUTHEAST TODAY AOB 10 KNOTS THEN GO WEST BY THIS EVENING AND DECREASE TO ABOUT 5 KNOTS. && .MARINE... ISSUED AT 310 AM EDT THU APR 16 2015 EAST WINDS 5 TO 15 KNOTS WILL NOT BE HAZARDOUS TO SMALL CRAFT TODAY. && .HYDROLOGY... ISSUED AT 310 AM EDT THU APR 16 2015 AROUND A TENTH OF AN INCH OF RAIN IS POSSIBLE TODAY. THIS WILL HAVE A NEGLIGIBLE EFFECT ON AREA RIVERS. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...04 SHORT TERM...04 LONG TERM...OSTUNO AVIATION...OSTUNO HYDROLOGY...04 MARINE...04
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
742 AM EDT THU APR 16 2015 .UPDATE... ISSUED AT 657 AM EDT THU APR 16 2015 DECIDED TO PUT SPRINKLES INTO FORECAST OVER EASTERN CWA /ISQ-ERY/ MID MORNING INTO EARLY AFTN AS BAND OF SHOWERS OVER LOWER MICHIGAN CONTINUES TO LIFT NORTHWARD. EVEN THOUGH SHRA WILL BE RUNNING INTO THE DRY AIRMASS OVER AREA AS SEEN ON 00Z APX AND DTX RAOBS...THINK ENOUGH FOCUS FM SHORTWAVE AND MOISTURE TRANSPORT AT H85-H7 IS GOING TO END UP STRONG/PERSISTENT ENOUGH TO OUTWEIGH THE LOW-LEVEL DRY AIR. VARIOUS HIGH RES MODELS AND THE 06Z/07Z HRRR REFLECTIVITY OUTPUT POINT TO AT LEAST A BRIEF PERIOD OF LGT RAIN/SPRINKLES. BEEFED UP SKY COVER SOME MORE AS WELL. OTHER THAN TWEAKS FOR VERY SHORT TERM TEMP/DWPNT TRENDS...NO OTHER CHANGES WERE NEEDED TO FORECAST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 435 AM EDT THU APR 16 2015 SHORTWAVE RIDGING PERSISTS TODAY BTWN NORTHERN STREAM SHORTWAVE THAT CROSSES MANITOBA/NORTHERN ONTARIO AND CUTOFF LOW OVER FOUR CORNERS OF SW CONUS. WEAK AREAS OF VORTICITY LIFTING INTO THE RIDGE BRINGING A PUSH OF MID-LEVEL MOISTURE ADVECTION AROUND H7. DECENT AREA OF SHRA IS LIFTING NORTHWARD OVER WESTERN LOWER MICHIGAN ON NORTH EDGE OF MOISTURE TRANSPORT AT H85-H7 AND THIS COULD BRING VIRGA OR A FEW SPRINKLES TO EASTERN CWA...POSSIBLY AS FAR WEST AS KESC PER HRRR MODEL LATE MORNING INTO EARLY AFTN. ELSEWHERE WILL CERTAINLY BE MORE CLOUDS THAN LAST COUPLE DAYS AS CIRRUS AND MORE PRONOUNCED AREA OF AC/AS OVER MN SLIDES IN FOR THE AFTN. EVEN SO THOUGH...WARM START SHOULD STILL ALLOW MAX TEMPS TO REACH WELL INTO THE 60S. RH VALUES A BIT HIGHER THAN BONE DRY CONDITIONS SEEN TUE/WED WHERE RH BOTTOMED OUT AROUND 10 PCT OVER INTERIOR WEST. FOR TODAY IN THOSE AREAS... EXPECT MAINLY 18-25 PCT RANGE AT THE LOW-END. WINDS LESS THAN 10 MPH MOST AREAS WITH LOCAL LAKE BREEZES CNTRL. OVERALL APPEARS TO NOT BE AS MUCH OF ISSUE WITH FIRE WEATHER TODAY COMPARED TO TUE OR WED. NORTHERN STREAM SHORTWAVE CROSSES NORTHERN ONTARIO TONIGHT WITH TAIL OF ENHANCED CLOUD GRAZING CWA...ALONG WITH THE PASSAGE OF SFC TROUGH...MORE OF A WIND SHIFT FM SW TO NW LATE TONIGHT. SINCE 1000- 700MB LAPSE RATES ARE HIGH...OVER 7C/KM BY LATE AFTN...AND FORCING IS MOVING THROUGH WITH SUFFICIENT MOISTURE ALOFT...THINK THERE IS A CHANCE OF SPRINKLES/VIRGA THIS EVENING AS THE FORCING MOVES THROUGH...PERHAPS SIMILAR TO WHAT OCCURRED MON AFTN/EVENING. THAT SAID...WINDS IN MIXED LAYER THIS EVENING DO INCREASE BY 03Z WITH 25- 30 KTS AT TOP PARTS OF THE MIXED LAYER. SO...FEASIBLE THAT GUSTY WINDS COULD OCCUR IN THE VCNTY OF ANY WELL DEVELOPED CU OR VIRGA/SPRINKLES. ALL FORCING IS OUT OF HERE BY MIDNIGHT AND SCT-BKN CLOUDS SHOULD EXIT OVERNIGHT. SKIES WILL BE MAINLY CLEAR BY DAYBREAK ON FRIDAY. LOWS TONIGHT SHOULD REMAIN ABOVE FREEZING ALL AREAS GIVEN THE WINDS AND CLOUDS MOST OF THE NIGHT AND LACK OF COLD AIR BEHIND THE TROUGH. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 436 PM EDT WED APR 15 2015 AFTER A QUIET AND GENERALLY WARM REST OF THIS WEEK...SIGNIFICANT AMPLIFICATION OF THE FLOW IS EXPECTED THIS WEEKEND AND EARLY NEXT WEEK AS A SHARP RIDGE BUILDS THRU WRN CANADA. THIS WILL FORCE A DEEP TROF TO DEVELOP DOWNSTREAM WITH AXIS ROUGHLY OVER THE MISSISSIPPI VALLEY BY MON. TYPICAL FOR THIS TIME OF YEAR...CLOSED LOWS FREQUENTLY DEVELOP...AND THIS TROF WILL QUICKLY EVOLVE IN THAT DIRECTION AS MAJORITY OF GUIDANCE INCLUDING GFS/GEM ENSEMBLES SHOW EVOLUTION INTO A LARGE/COLD MID-LEVEL LOW OVER THE VICINITY OF THE UPPER GREAT LAKES. MAY BE DIFFICULT TO DISLODGE THE LOW NEXT WEEK ONCE IT DEVELOPS. SO...AFTER A WARM/DRY REST OF THIS WEEK...NEXT WEEK WILL BE COLD AND GENERALLY UNSETTLED WITH PERIODIC CHANCES OF SNOW AND RAIN SHOWERS. FROM A PCPN PERSPECTIVE...THE BIGGEST CHALLENGE IS HOW THE SHARP PATTERN AMPLIFICATION INTERACTS WITH WHAT IS CURRENTLY AN IMPRESSIVE LOOKING TROF CLOSING OFF OVER UT/CO. MEDIUM RANGE GUIDANCE TODAY IS IN MUCH BETTER AGREEMENT IN SHOWING THE AMPLIFICATION OF THE FLOW PICKING UP THE MID-LEVEL LOW AND FORCING THE OPENED UP SYSTEM/REMNANT ENERGY NE INTO THE GREAT LAKES REGION. RANGE OF POSSIBILITIES STILL INCLUDE A SIGNIFICANT RAIN EVENT TO A RAIN CHANGING TO ACCUMULATING SNOW EVENT TO MINIMAL PCPN IF THE SRN ENERGY DOES NOT LIFT FAR ENOUGH N AND W WITHIN THE AMPLIFYING PATTERN. OPERATIONAL MEDIUM RANGE MODELS WEAKEN THE ENERGY DRAMATICALLY AS IT LIFTS NE (WILL BE INTERESTING TO SEE IF THAT ACTUALLY HAPPENS)...SO THE LOWEST PROBABILITY OUTCOME RIGHT NOW IS ONE THAT BRINGS A SIGNIFICANT PCPN PRODUCING SYSTEM WITH A PROMINENT DEFORMATION PCPN SHIELD INTO THE UPPER LAKES EARLY NEXT WEEK. THAT SAID...THERE HAVE BEEN AND THERE STILL ARE SOME GFS/GEM ENSEMBLES THAT DO SHOW SUCH A SCENARIO...SO IT CAN`T BE RULED OUT. BEGINNING THU NIGHT...TAIL END OF SHORTWAVE TRACKING FROM HUDSON BAY INTO QUEBEC WILL PASS ACROSS THE AREA THU NIGHT. FORCING FROM THE RIGHT ENTRANCE OF AN UPPER JET STREAK AND MAIN DEEP LAYER QVECTOR CONVERGENCE...WEAK AT THAT...PASS N OF THE AREA...SUPPORTING BEST CHC OF -SHRA N OF HERE. ACROSS UPPER MI...VERY WEAK FORCING/WEAK FRONTAL BOUNDARY AND WEAK MOISTURE TRANSPORT ALL SUGGEST PROSPECT OF ANY PCPN IS VERY LIMITED AS SHORTWAVE PASSES. THUS...WILL RETAIN DRY FCST FOR THU NIGHT. IN THE MAIN FLOW TO THE N...ANOTHER SHORTWAVE IS FCST TO TRACK FROM THE CANADIAN ROCKIES THU AFTN TO NRN ONTARIO FRI. MODELS HAVE TRENDED TO MUCH BETTER AGREEMENT ON THIS WAVE WITH GEM/GFS/NAM MOVING TO THE ECMWF SCENARIO WHICH HAS BEEN FARTHER N THAN THOSE MODELS FOR SEVERAL RUNS. WITH THE TRACK OF THE SHORTWAVE JUST N OF LAKE SUPERIOR...BEST FORCING AND POTENTIAL FOR PCPN WILL PASS BY TO THE N. REMOVED SCHC POPS FROM INHERITED FCST IN FAVOR OF DRY WEATHER. EXPECT HIGH TEMPS FRI IN THE 60S AWAY FROM LAKE MODERATION. A FEW SPOTS MAY REACH 70F. INTERIOR RH SHOULD FALL TO 25-30PCT... AND WINDS MAY BE A LITTLE GUSTY TO 15-20MPH AT TIMES...KEEPING FIRE WX A CONCERN. IN THE WAKE OF THE SHORTWAVE...HIGH PRES BUILDS INTO THE AREA FOR SAT. WITH THE HIGH ENDING UP OVER LAKE SUPERIOR IN THE AFTN...IT WILL BE A MUCH COOLER DAY NEAR LAKE SUPERIOR...ESPECIALLY FROM THE KEWEENAW EASTWARD. RIGHT ALONG THE SHORE...TEMPS SHOULDN`T GET OUT OF THE 30S. IN THE INTERIOR W HALF...TEMPS SHOULD RISE TO AROUND 60F UNDER SUNNY SKIES. SUN/MON...WILL CONTINUE TO UTILIZE A CONSENSUS APPROACH OF CURRENT AND RECENT MEDIUM RANGE GUIDANCE FOR THE EVOLUTION OF THE SRN ROCKIES ENERGY INTO THE GREAT LAKES AHEAD OF THE TROF AMPLIFICATION OCCURRING INTO THE PLAINS/MISSISSIPPI VALLEY. IT APPEARS THERE MAY END UP BEING TWO SURGES OF PCPN OR SFC LOW PRES WAVES...ONE ASSOCIATED WITH LEAD ENERGY SWINGING UP FROM MEXICO AND A SECOND ASSOCIATED WITH THE MAIN REMNANT OF THE ROCKIES MID LEVEL LOW. LATEST GUIDANCE SUGGESTS RAIN WILL BEGIN SPREADING INTO UPPER MI SUN AND THEN CONTINUE INTO MON. AIR MASS SHOULD COOL ENOUGH TO ALLOW SOME SNOW TO BEGIN MIXING WITH THE RAIN OVER THE W ON MON. PTYPE WILL THEN BECOME ALL SNOW ACROSS THE FCST AREA MON NIGHT FOR WHATEVER PCPN LINGERS. TUE/WED...LARGE/COLD MID-LEVEL LOW WILL HAVE DEVELOPED AND WILL BE CENTERED IN THE VCNTY OF THE UPPER GREAT LAKES. COLD AIR ALOFT/SPRING DAYTIME HEATING AND POTENTIAL OF SHORTWAVES ROTATING THRU THE AREA WITHIN THE LARGE MID-LEVEL LOW CIRCULATION SUGGEST AT LEAST SCT SHOWERY PCPN (MOSTLY SNOW BUT SOME RAIN AS WELL DURING PEAK HEATING) BOTH DAYS WITH BEST COVERAGE IN THE AFTN INLAND FROM LAKE SUPERIOR WHERE HEATING IS BEST. HIGH TEMPS BOTH DAYS SHOULD BE IN THE MID 30S TO MID 40S...WARMEST SCNTRL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 742 AM EDT THU APR 16 2015 EVEN THOUGH MID TO HIGH CLOUDS WILL THICKEN THROUGH THIS EVENING AS A WEAK UPR DISTURBANCE MOVES TOWARD THE UPR LKS AND MOISTURE INCREASES ALOFT...LINGERING LLVL DRY AIR ASSOCIATED WITH A SFC HI PRES RDG WL BRING CONTINUED VFR CONDITIONS. EXPECT A SFC TROUGH TO CROSS UPR MICHIGAN TONIGHT WITH A WIND SHIFT FM SW TO NW. WINDS SHOULD STAY LIGHT THOUGH. IT IS POSSIBLE THERE COULD BE A LGT SHOWER OR SPRINKLE AROUND EARLY THIS EVENING AHEAD OF THE FRONT. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 435 AM EDT THU APR 16 2015 NO WIDESPREAD GALES ARE EXPECTED THROUGH THE FORECAST PERIOD...BUT THERE WILL BE A FEW PERIODS OF STRONGER WINDS STARTING THIS WEEKEND. WINDS EXPECTED TO REMAIN AT OR BLO 20 KTS THROUGH FRIDAY NIGHT AS PRESSURE GRADIENT IS WEAK. HIGH PRESSURE MOVING ACROSS ON SATURDAY WITH LOW PRESSURE FOLLOWING OVER SCNTRL CANADA ON SUNDAY WILL RESULT IN SETUP FOR STRONGER EAST-NORTHEAST WINDS TO 30 KTS OVER WESTERN LK SUPERIOR SATURDAY AND SATURDAY NIGHT. STRONGEST WINDS WILL BE TOWARD HEAD OF LK SUPERIOR NEAR DULUTH AND SUPERIOR. BY SUNDAY...AS THE LOW PRESSURE SYSTEM APPROACHES...SOUTHEAST WINDS TO 30 KTS WILL BE POSSIBLE OVER EASTERN HALF OF LK SUPERIOR WHILE WINDS DIMINISH IN THE WEST. THE LOW CROSSES THE UPPER GREAT LAKES BY MONDAY WHILE MERGING WITH ANOTHER LOW LIFTING IN FM THE CENTRAL PLAINS. EXPECT WEST WINDS UP TO 30 KTS OVER MUCH OF THE LAKE LATER MONDAY INTO TUESDAY IN WAKE OF THIS COMBINED LOW AS IT MOVES TO THE LOWER GREAT LAKES. && .HYDROLOGY... ISSUED AT 332 PM EDT WED APR 15 2015 SEEMS THAT WITHOUT ANY SIGNIFICANT ADDITIONAL PRECIPITATION ADDED TO THE ONGOING SNOWMELT...AT LEAST FOR THE REST OF THIS WEEK...MAINLY LOOKING AT A FEW BANKFULL ISSUES ON SOME RIVERS WITH CONTINUATION OF LOW-END ADVISORIES. BELOW NORMAL TEMPERATURES ARE EXPECTED MONDAY THROUGH MUCH OF NEXT WEEK...WHICH WILL LIMIT MELTING OF ANY REMAINING SNOW PACK AND REDUCE RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SHORT TERM...JLA LONG TERM...ROLFSON AVIATION...JLA MARINE...JLA HYDROLOGY...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
658 AM EDT THU APR 16 2015 .UPDATE... ISSUED AT 657 AM EDT THU APR 16 2015 DECIDED TO PUT SPRINKLES INTO FORECAST OVER EASTERN CWA /ISQ-ERY/ MID MORNING INTO EARLY AFTN AS BAND OF SHOWERS OVER LOWER MICHIGAN CONTINUES TO LIFT NORTHWARD. EVEN THOUGH SHRA WILL BE RUNNING INTO THE DRY AIRMASS OVER AREA AS SEEN ON 00Z APX AND DTX RAOBS...THINK ENOUGH FOCUS FM SHORTWAVE AND MOISTURE TRANSPORT AT H85-H7 IS GOING TO END UP STRONG/PERSISTENT ENOUGH TO OUTWEIGH THE LOW-LEVEL DRY AIR. VARIOUS HIGH RES MODELS AND THE 06Z/07Z HRRR REFLECTIVITY OUTPUT POINT TO AT LEAST A BRIEF PERIOD OF LGT RAIN/SPRINKLES. BEEFED UP SKY COVER SOME MORE AS WELL. OTHER THAN TWEAKS FOR VERY SHORT TERM TEMP/DWPNT TRENDS...NO OTHER CHANGES WERE NEEDED TO FORECAST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 435 AM EDT THU APR 16 2015 SHORTWAVE RIDGING PERSISTS TODAY BTWN NORTHERN STREAM SHORTWAVE THAT CROSSES MANITOBA/NORTHERN ONTARIO AND CUTOFF LOW OVER FOUR CORNERS OF SW CONUS. WEAK AREAS OF VORTICITY LIFTING INTO THE RIDGE BRINGING A PUSH OF MID-LEVEL MOISTURE ADVECTION AROUND H7. DECENT AREA OF SHRA IS LIFTING NORTHWARD OVER WESTERN LOWER MICHIGAN ON NORTH EDGE OF MOISTURE TRANSPORT AT H85-H7 AND THIS COULD BRING VIRGA OR A FEW SPRINKLES TO EASTERN CWA...POSSIBLY AS FAR WEST AS KESC PER HRRR MODEL LATE MORNING INTO EARLY AFTN. ELSEWHERE WILL CERTAINLY BE MORE CLOUDS THAN LAST COUPLE DAYS AS CIRRUS AND MORE PRONOUNCED AREA OF AC/AS OVER MN SLIDES IN FOR THE AFTN. EVEN SO THOUGH...WARM START SHOULD STILL ALLOW MAX TEMPS TO REACH WELL INTO THE 60S. RH VALUES A BIT HIGHER THAN BONE DRY CONDITIONS SEEN TUE/WED WHERE RH BOTTOMED OUT AROUND 10 PCT OVER INTERIOR WEST. FOR TODAY IN THOSE AREAS... EXPECT MAINLY 18-25 PCT RANGE AT THE LOW-END. WINDS LESS THAN 10 MPH MOST AREAS WITH LOCAL LAKE BREEZES CNTRL. OVERALL APPEARS TO NOT BE AS MUCH OF ISSUE WITH FIRE WEATHER TODAY COMPARED TO TUE OR WED. NORTHERN STREAM SHORTWAVE CROSSES NORTHERN ONTARIO TONIGHT WITH TAIL OF ENHANCED CLOUD GRAZING CWA...ALONG WITH THE PASSAGE OF SFC TROUGH...MORE OF A WIND SHIFT FM SW TO NW LATE TONIGHT. SINCE 1000- 700MB LAPSE RATES ARE HIGH...OVER 7C/KM BY LATE AFTN...AND FORCING IS MOVING THROUGH WITH SUFFICIENT MOISTURE ALOFT...THINK THERE IS A CHANCE OF SPRINKLES/VIRGA THIS EVENING AS THE FORCING MOVES THROUGH...PERHAPS SIMILAR TO WHAT OCCURRED MON AFTN/EVENING. THAT SAID...WINDS IN MIXED LAYER THIS EVENING DO INCREASE BY 03Z WITH 25- 30 KTS AT TOP PARTS OF THE MIXED LAYER. SO...FEASIBLE THAT GUSTY WINDS COULD OCCUR IN THE VCNTY OF ANY WELL DEVELOPED CU OR VIRGA/SPRINKLES. ALL FORCING IS OUT OF HERE BY MIDNIGHT AND SCT-BKN CLOUDS SHOULD EXIT OVERNIGHT. SKIES WILL BE MAINLY CLEAR BY DAYBREAK ON FRIDAY. LOWS TONIGHT SHOULD REMAIN ABOVE FREEZING ALL AREAS GIVEN THE WINDS AND CLOUDS MOST OF THE NIGHT AND LACK OF COLD AIR BEHIND THE TROUGH. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 436 PM EDT WED APR 15 2015 AFTER A QUIET AND GENERALLY WARM REST OF THIS WEEK...SIGNIFICANT AMPLIFICATION OF THE FLOW IS EXPECTED THIS WEEKEND AND EARLY NEXT WEEK AS A SHARP RIDGE BUILDS THRU WRN CANADA. THIS WILL FORCE A DEEP TROF TO DEVELOP DOWNSTREAM WITH AXIS ROUGHLY OVER THE MISSISSIPPI VALLEY BY MON. TYPICAL FOR THIS TIME OF YEAR...CLOSED LOWS FREQUENTLY DEVELOP...AND THIS TROF WILL QUICKLY EVOLVE IN THAT DIRECTION AS MAJORITY OF GUIDANCE INCLUDING GFS/GEM ENSEMBLES SHOW EVOLUTION INTO A LARGE/COLD MID-LEVEL LOW OVER THE VICINITY OF THE UPPER GREAT LAKES. MAY BE DIFFICULT TO DISLODGE THE LOW NEXT WEEK ONCE IT DEVELOPS. SO...AFTER A WARM/DRY REST OF THIS WEEK...NEXT WEEK WILL BE COLD AND GENERALLY UNSETTLED WITH PERIODIC CHANCES OF SNOW AND RAIN SHOWERS. FROM A PCPN PERSPECTIVE...THE BIGGEST CHALLENGE IS HOW THE SHARP PATTERN AMPLIFICATION INTERACTS WITH WHAT IS CURRENTLY AN IMPRESSIVE LOOKING TROF CLOSING OFF OVER UT/CO. MEDIUM RANGE GUIDANCE TODAY IS IN MUCH BETTER AGREEMENT IN SHOWING THE AMPLIFICATION OF THE FLOW PICKING UP THE MID-LEVEL LOW AND FORCING THE OPENED UP SYSTEM/REMNANT ENERGY NE INTO THE GREAT LAKES REGION. RANGE OF POSSIBILITIES STILL INCLUDE A SIGNIFICANT RAIN EVENT TO A RAIN CHANGING TO ACCUMULATING SNOW EVENT TO MINIMAL PCPN IF THE SRN ENERGY DOES NOT LIFT FAR ENOUGH N AND W WITHIN THE AMPLIFYING PATTERN. OPERATIONAL MEDIUM RANGE MODELS WEAKEN THE ENERGY DRAMATICALLY AS IT LIFTS NE (WILL BE INTERESTING TO SEE IF THAT ACTUALLY HAPPENS)...SO THE LOWEST PROBABILITY OUTCOME RIGHT NOW IS ONE THAT BRINGS A SIGNIFICANT PCPN PRODUCING SYSTEM WITH A PROMINENT DEFORMATION PCPN SHIELD INTO THE UPPER LAKES EARLY NEXT WEEK. THAT SAID...THERE HAVE BEEN AND THERE STILL ARE SOME GFS/GEM ENSEMBLES THAT DO SHOW SUCH A SCENARIO...SO IT CAN`T BE RULED OUT. BEGINNING THU NIGHT...TAIL END OF SHORTWAVE TRACKING FROM HUDSON BAY INTO QUEBEC WILL PASS ACROSS THE AREA THU NIGHT. FORCING FROM THE RIGHT ENTRANCE OF AN UPPER JET STREAK AND MAIN DEEP LAYER QVECTOR CONVERGENCE...WEAK AT THAT...PASS N OF THE AREA...SUPPORTING BEST CHC OF -SHRA N OF HERE. ACROSS UPPER MI...VERY WEAK FORCING/WEAK FRONTAL BOUNDARY AND WEAK MOISTURE TRANSPORT ALL SUGGEST PROSPECT OF ANY PCPN IS VERY LIMITED AS SHORTWAVE PASSES. THUS...WILL RETAIN DRY FCST FOR THU NIGHT. IN THE MAIN FLOW TO THE N...ANOTHER SHORTWAVE IS FCST TO TRACK FROM THE CANADIAN ROCKIES THU AFTN TO NRN ONTARIO FRI. MODELS HAVE TRENDED TO MUCH BETTER AGREEMENT ON THIS WAVE WITH GEM/GFS/NAM MOVING TO THE ECMWF SCENARIO WHICH HAS BEEN FARTHER N THAN THOSE MODELS FOR SEVERAL RUNS. WITH THE TRACK OF THE SHORTWAVE JUST N OF LAKE SUPERIOR...BEST FORCING AND POTENTIAL FOR PCPN WILL PASS BY TO THE N. REMOVED SCHC POPS FROM INHERITED FCST IN FAVOR OF DRY WEATHER. EXPECT HIGH TEMPS FRI IN THE 60S AWAY FROM LAKE MODERATION. A FEW SPOTS MAY REACH 70F. INTERIOR RH SHOULD FALL TO 25-30PCT... AND WINDS MAY BE A LITTLE GUSTY TO 15-20MPH AT TIMES...KEEPING FIRE WX A CONCERN. IN THE WAKE OF THE SHORTWAVE...HIGH PRES BUILDS INTO THE AREA FOR SAT. WITH THE HIGH ENDING UP OVER LAKE SUPERIOR IN THE AFTN...IT WILL BE A MUCH COOLER DAY NEAR LAKE SUPERIOR...ESPECIALLY FROM THE KEWEENAW EASTWARD. RIGHT ALONG THE SHORE...TEMPS SHOULDN`T GET OUT OF THE 30S. IN THE INTERIOR W HALF...TEMPS SHOULD RISE TO AROUND 60F UNDER SUNNY SKIES. SUN/MON...WILL CONTINUE TO UTILIZE A CONSENSUS APPROACH OF CURRENT AND RECENT MEDIUM RANGE GUIDANCE FOR THE EVOLUTION OF THE SRN ROCKIES ENERGY INTO THE GREAT LAKES AHEAD OF THE TROF AMPLIFICATION OCCURRING INTO THE PLAINS/MISSISSIPPI VALLEY. IT APPEARS THERE MAY END UP BEING TWO SURGES OF PCPN OR SFC LOW PRES WAVES...ONE ASSOCIATED WITH LEAD ENERGY SWINGING UP FROM MEXICO AND A SECOND ASSOCIATED WITH THE MAIN REMNANT OF THE ROCKIES MID LEVEL LOW. LATEST GUIDANCE SUGGESTS RAIN WILL BEGIN SPREADING INTO UPPER MI SUN AND THEN CONTINUE INTO MON. AIR MASS SHOULD COOL ENOUGH TO ALLOW SOME SNOW TO BEGIN MIXING WITH THE RAIN OVER THE W ON MON. PTYPE WILL THEN BECOME ALL SNOW ACROSS THE FCST AREA MON NIGHT FOR WHATEVER PCPN LINGERS. TUE/WED...LARGE/COLD MID-LEVEL LOW WILL HAVE DEVELOPED AND WILL BE CENTERED IN THE VCNTY OF THE UPPER GREAT LAKES. COLD AIR ALOFT/SPRING DAYTIME HEATING AND POTENTIAL OF SHORTWAVES ROTATING THRU THE AREA WITHIN THE LARGE MID-LEVEL LOW CIRCULATION SUGGEST AT LEAST SCT SHOWERY PCPN (MOSTLY SNOW BUT SOME RAIN AS WELL DURING PEAK HEATING) BOTH DAYS WITH BEST COVERAGE IN THE AFTN INLAND FROM LAKE SUPERIOR WHERE HEATING IS BEST. HIGH TEMPS BOTH DAYS SHOULD BE IN THE MID 30S TO MID 40S...WARMEST SCNTRL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 208 AM EDT THU APR 16 2015 ALTHOUGH THERE WL BE SOME THICKENING HI/MID CLDS LATER TODAY AS A WEAK UPR DISTURBANCE MOVES TOWARD THE UPR LKS...LINGERING LLVL DRY AIR ASSOCIATED WITH A SFC HI PRES RDG WL BRING CONTINUED VFR CONDITIONS. STRONGER S WINDS ABOVE LIGHTER GROUND LVL WINDS WITHIN A NEAR SFC STABLE LYR CAUSED BY NOCTURNAL COOLING WL ALLOW FOR SOME LLWS AT THE SITES EARLY THIS MRNG...BUT WINDS WL DIMINISH SGNFTLY BY SUNRISE... ENDING THE LLWS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 435 AM EDT THU APR 16 2015 NO WIDESPREAD GALES ARE EXPECTED THROUGH THE FORECAST PERIOD...BUT THERE WILL BE A FEW PERIODS OF STRONGER WINDS STARTING THIS WEEKEND. WINDS EXPECTED TO REMAIN AT OR BLO 20 KTS THROUGH FRIDAY NIGHT AS PRESSURE GRADIENT IS WEAK. HIGH PRESSURE MOVING ACROSS ON SATURDAY WITH LOW PRESSURE FOLLOWING OVER SCNTRL CANADA ON SUNDAY WILL RESULT IN SETUP FOR STRONGER EAST-NORTHEAST WINDS TO 30 KTS OVER WESTERN LK SUPERIOR SATURDAY AND SATURDAY NIGHT. STRONGEST WINDS WILL BE TOWARD HEAD OF LK SUPERIOR NEAR DULUTH AND SUPERIOR. BY SUNDAY...AS THE LOW PRESSURE SYSTEM APPROACHES...SOUTHEAST WINDS TO 30 KTS WILL BE POSSIBLE OVER EASTERN HALF OF LK SUPERIOR WHILE WINDS DIMINISH IN THE WEST. THE LOW CROSSES THE UPPER GREAT LAKES BY MONDAY WHILE MERGING WITH ANOTHER LOW LIFTING IN FM THE CENTRAL PLAINS. EXPECT WEST WINDS UP TO 30 KTS OVER MUCH OF THE LAKE LATER MONDAY INTO TUESDAY IN WAKE OF THIS COMBINED LOW AS IT MOVES TO THE LOWER GREAT LAKES. && .HYDROLOGY... ISSUED AT 332 PM EDT WED APR 15 2015 SEEMS THAT WITHOUT ANY SIGNIFICANT ADDITIONAL PRECIPITATION ADDED TO THE ONGOING SNOWMELT...AT LEAST FOR THE REST OF THIS WEEK...MAINLY LOOKING AT A FEW BANKFULL ISSUES ON SOME RIVERS WITH CONTINUATION OF LOW-END ADVISORIES. BELOW NORMAL TEMPERATURES ARE EXPECTED MONDAY THROUGH MUCH OF NEXT WEEK...WHICH WILL LIMIT MELTING OF ANY REMAINING SNOW PACK AND REDUCE RIVER LEVELS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SHORT TERM...JLA LONG TERM...ROLFSON AVIATION...KC MARINE...JLA HYDROLOGY...TITUS
AREA FORECAST DISCUSSION
NWS DULUTH MN
345 AM CDT THU APR 16 2015 .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 343 AM CDT THU APR 16 2015 CURRENT RADAR IMAGERY SHOWS SCATTERED ECHOS LIFTING NORTH OVER MUCH OF MN EARLY THIS MORNING IN A REGION OF MID LEVEL WARM AIR ADVECTION AHEAD OF AN APPROACHING COLD FRONT. HOWEVER...THE VERY DRY AIR IN PLACE IS LIMITING MORE THAN A FEW SPRINKLES FROM REACHING THE GROUND WITH CEILINGS REMAINING ABOVE 6 KFT. THE MORNING CONVECTION WILL DISSIPATE AFTER SUNRISE...REDEVELOPING ALONG THE FRONTAL BOUNDARY THIS AFTERNOON IN THE BORDERLAND/ARROWHEAD REGION. ANY SHOWERS THAT DEVELOP LATE TODAY WILL AGAIN HAVE TO CONTENT WITH VERY DRY LOW LEVELS...RESULTING IN PRIMARILY VIRGA AND LIMITING ANY QPF TO ONLY A FEW HUNDREDTHS AT BEST. LOCATIONS THAT DO RECEIVE A PASSING SPRINKLE/VIRGA CAN EXPECT A LOCALIZED WIND GUST TO 25 MPH THIS AFTERNOON...MAINLY IN THE MN ARROWHEAD. THE FRONT WILL REACH THE WISCONSIN ZONES THIS EVENING...BRINGING INCREASING CLOUDS AND LIGHT AND VARIABLE WINDS. THE CLOUD COVER TODAY WILL ALLOW FOR SOMEWHAT COOLER TEMPERATURES THAN THE PAST FEW DAYS...TOPPING OUT IN THE LOW TO MIDDLE 60S TODAY. HOWEVER...THIS IS STILL 10 TO 15 DEGREES ABOVE NORMAL FOR MID APRIL. TEMPERATURES CLOSER TO 70 WILL RETURN WITH SUNNY SKIES FRIDAY AS RIDGE OF HIGH PRESSURE BUILDS ACROSS THE NORTHLAND. A CORRIDOR OF VERY DRY AIR WITH RH VALUES IN TEENS TO LOW 20S IS EXPECTED TO SETTLE OVER THE NE MINN AND FAR NRN WISCONSIN THROUGH FRIDAY EVENING. WINDS WILL BE OUT OF THE WEST AROUND 5 TO 10 MPH OVER MOST AREAS FRIDAY...EXCEPT STRONGER WITH GUSTS TO 25 MPH ALONG THE INTERNATIONAL BORDER AS A COLD FRONT IN ONTARIO APPROACHES THE BORDERLAND. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 343 AM CDT THU APR 16 2015 FRIDAY NIGHT...A SUBTLE COLD FRONT WILL MOVE INTO THE NORTHLAND IN THE WAKE OF A WEAK LOW MOVING THROUGH ONTARIO INTO QUEBEC. HIGH PRESSURE WILL BUILD INTO ONTARIO AND THE LAKE SUPERIOR REGION IN THE WAKE OF THE FRONT. THE NORTHLAND CAN EXPECT A CLEAR AND COOL NIGHT WITH LIGHT WINDS. SATURDAY...THE DAY WILL BEGIN COOL AND CLEAR. EASTERLY WINDS WILL DEVELOP AS THE HIGH PRESSURE SHIFTS EAST TOWARDS QUEBEC AND THE EASTERN GREAT LAKES AND IN RESPONSE TO LOW PRESSURE BUILDING INTO THE AMERICAN AND CANADIAN PLAINS. THERE WILL BE A CUTOFF LOW OVER THE HIGH PLAINS OF COLORADO...AND A DEEPENING LOW IN CENTRAL SASKATCHEWAN MOVING TO THE SE. THERE WILL BE INCREASING CLOUD COVER OVER THE NORTHLAND SATURDAY AS THE MOISTURE FROM THE CUTOFF LOW BEGINS TO MOVE INTO THE NORTHLAND FROM THE SOUTH. THE EAST TO NE FLOW OFF OF LAKE SUPERIOR WILL KEEP AREAS NEAR LAKE SUPERIOR COOL IN THE UPPER 40S AND 50S...BUT AREAS OF THE NORTHLAND WELL INLAND SHOULD CLIMB TO THE LOWER 60S. SATURDAY NIGHT AND SUNDAY...THE LOW IN SASKATCHEWAN WILL DEEPEN AS IT MOVES SE INTO MANITOBA. THE CUTOFF LOW NEAR THE COLORADO/NEBRASKA BORDER WILL MOVE ENE TOWARDS THE UPPER MIDWEST. SURFACE LOW PRESSURE WILL DEVELOP IN THE DAKOTAS SATURDAY NIGHT AND MOVE INTO THE NORTHLAND AND MERGE WITH THE LOW IN SOUTH CENTRAL CANADA. THE LOW PRESSURE WILL BRING A SURGE OF HUMID AIR AND RAIN INTO THE NORTHLAND SATURDAY NIGHT AND SUNDAY. THE MODELS ARE IN BETTER AGREEMENT ON THE TIMING OF THIS PCPN COMPARED TO PREVIOUS RUNS...ESPECIALLY BETWEEN THE GFS AND ECMWF. THEREFORE...WAS ABLE TO INCREASE PCPN CHANCES BY ABOUT 10 TO 20 PERCENT. THE PRECIPITABLE WATER VALUES WILL INCREASE TO AROUND 1 INCH. THE NORTHLAND WILL LIKELY GET AT LEAST WIDESPREAD RAINFALL OF 0.50" TO 0.75" OF RAINFALL WITH THE PASSAGE OF THIS LOW PRESSURE. EARLY NEXT WEEK...THE LOW PRESSURE SYSTEMS WILL MERGE AND DEEPEN INTO A LARGE LOW PRESSURE SYSTEM OVER THE GREAT LAKES AND ONTARIO REGION. THE NORTHLAND CAN EXPECT A PERIOD OF COOLER AND CLOUDIER WEATHER FOR THE MONDAY THROUGH WEDNESDAY TIMEFRAME WITH CHANCES OF RAIN AND LIGHT SNOW SHOWERS. TEMPERATURES WILL BE ABOUT 10 DEGREES BELOW NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 104 AM CDT THU APR 16 2015 VFR CONDITIONS EXPECTED THROUGHOUT THE FORECAST. INCREASING AMOUNT OF MOISTURE MOVING INTO THE NORTHLAND AS HIGH PRESSURE DEPARTS TO THE EAST...AND AN UPPER LEVEL DISTURBANCE MOVES THROUGH MINNESOTA. LAST SEVERAL HRRR RUNS SHOW THE BEST CHANCE OF -RA AT KBRD. OTHER MN TERMINALS MAY SEE VCSH BETWEEN 14Z AND 20Z THIS MORNING...BUT NOT VERY CONFIDENT THAT MUCH IF ANY WILL REACH THE GROUND AS LATEST GFS AND NAM SOUNDINGS KEEP THE LOW LEVELS FAIRLY DRY. && .PRELIMINARY POINT TEMPS/POPS... DLH 62 37 67 39 / 10 10 0 0 INL 62 31 67 33 / 20 10 10 0 BRD 67 36 70 41 / 20 10 0 0 HYR 65 37 70 38 / 10 10 0 0 ASX 67 37 69 37 / 10 10 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...GRANING LONG TERM...GROCHOCINSKI AVIATION...GROCHOCINSKI/WL
AREA FORECAST DISCUSSION
NWS DULUTH MN
105 AM CDT THU APR 16 2015 .SHORT TERM...(THIS EVENING THROUGH THURSDAY AFTERNOON) ISSUED AT 326 PM CDT WED APR 15 2015 MAIN CONCERNS IN THE SHORT TERM REMAIN FOCUSED AROUND THE GUSTY SOUTH WINDS AND VERY DRY CONDITIONS ACROSS THE REGION THIS EVENING...THE POTENTIAL FOR LIGHT RAIN SHOWERS OVERNIGHT TONIGHT AND THROUGH THE DAY THURSDAY ACROSS NE MN. HIGH PRESSURE AT THE SURFACE REMAINS SITUATED OVER THE NRN GREAT LAKES WITH AN ELONGATED SFC TROUGH EXTENDING FROM NRN MANITOBA SWD INTO THE WRN DAKOTAS. THE COMBINATION OF THESE TWO FEATURES IS PRODUCING A TIGHT SFC PRESSURE GRADIENT OVER THE ERN DAKOTAS AND MOST OF MINNESOTA. GUSTY SOUTH WINDS HAVE DEVELOPED OVER THE REGION WITH SUSTAINED WINDS AROUND 10 TO 20 MPH AND GUSTS UP TO 35 MPH HAVE BEEN OBSERVED THIS AFTERNOON. AN EMBEDDED S/W IS CURRENTLY LIFTING TO THE NORTH THROUGH THE MID MS VALLEY REGION THIS AFTERNOON AND TRYING TO UNDERCUT THE SFC HIGH WITH CLOUD COVER AND LIGHT RAIN. HOWEVER...FOR THE TIME THE DRY AIR MASS IS WINNING OUT AND KEEPING MUCH OF THE AREA FREE OF PRECIPITATION. THE INFLUENCE FROM THE RIDGE TO THE EAST WILL EVENTUALLY MOVE TO THE EAST TONIGHT AS THE UPPER TROUGH LIFTS INTO MN. THIS WILL ALLOW FOR A STRONGER PUSH OF CLOUD COVER FROM THE SOUTH ALONG WITH LOW CHANCES FOR LIGHT RAIN SHOWERS...MAINLY OVER N-CENTRAL MN JUST AFTER MIDNIGHT AND THEN EVENTUALLY SHIFTING TO THE EAST INTO THE ARROWHEAD THROUGH THE DAY THURSDAY AS THE SFC TROUGH/COLD FRONT IS DRAGGED SLOWLY TO THE EAST. ONLY EXPECTING LIGHT AMOUNTS LESS THAN A TENTH OF AN INCH WITH THIS RAIN EVENT. HIGH PRESSURE WILL BUILD IN BRIEFLY BEHIND THE DEPARTING COLD FRONT LATE THUR AFTERNOON. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 326 PM CDT WED APR 15 2015 SFC RIDGING COVERS THE FORECAST AREA THURSDAY NIGHT THROUGH SATURDAY. THE GFS IS WAY OVERDONE WITH ITS HANDLING OF A SYSTEM ON SATURDAY AND WAS IGNORED. SATURDAY NIGHT FINDS RAIN ARRIVING OVER MUCH OF THE AREA AS A CLOSED UPPER LOW DEVELOPS OVER THE MANITOBA LAKES. AS THIS UPPER LOW DEEPENS WHILE MOVING SLOWLY EASTWARD...IT MERGES WITH A SOUTHERN STREAM SYSTEM ON SUNDAY. THIS PULLS MORE MOISTURE INTO THE AREA FOR THIS PHASING SYSTEM TO FEED OFF OF. ON SUNDAY NIGHT...THE UPPER LOW CONTINUES TO DEEPEN AND BEGINS TO PULL DOWN COLDER AIR FROM THE ARCTIC...MUCH LIKE A WINTER SYSTEM. HOWEVER...AT THIS TIME OF THE YEAR IT IS BECOMING MORE DIFFICULT TO HAVE A TRUE SNOW EVENT. THIS SYSTEM THEN BECOMES LOCKED IN PLACE JUST NORTH OF LAKE SUPERIOR THROUGH TUESDAY. WILL SEE RAIN DURING THE DAY AND A RAIN/SNOW MIX IN THE EVENING...WITH JUST A FEW SHORT HOURS OF ALL SNOW POSSIBLE LATE EACH NIGHT. NO SNOW ACCUMULATION IS EXPECTED. MAX AND MIN TEMPS WILL BECOME BELOW NORMAL SATURDAY NIGHT THROUGH TUESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 104 AM CDT THU APR 16 2015 VFR CONDITIONS EXPECTED THROUGHOUT THE FORECAST. INCREASING AMOUNT OF MOISTURE MOVING INTO THE NORTHLAND AS HIGH PRESSURE DEPARTS TO THE EAST...AND AN UPPER LEVEL DISTURBANCE MOVES THROUGH MINNESOTA. LAST SEVERAL HRRR RUNS SHOW THE BEST CHANCE OF -RA AT KBRD. OTHER MN TERMINALS MAY SEE VCSH BETWEEN 14Z AND 20Z THIS MORNING...BUT NOT VERY CONFIDENT THAT MUCH IF ANY WILL REACH THE GROUND AS LATEST GFS AND NAM SOUNDINGS KEEP THE LOW LEVELS FAIRLY DRY. && .PRELIMINARY POINT TEMPS/POPS... DLH 38 65 37 57 / 10 0 0 10 INL 33 64 33 61 / 0 10 0 10 BRD 36 67 35 63 / 10 0 0 10 HYR 37 67 38 63 / 10 0 0 10 ASX 37 67 37 58 / 10 0 0 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...BJT LONG TERM...GSF AVIATION...GROCHOCINSKI/WL
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1216 PM CDT THU APR 16 2015 .UPDATE... ISSUED AT 1215 PM CDT THU APR 16 2015 OBVIOUSLY A VERY TRICKY WEATHER PATTERN WE ARE IN FOR THE NEXT FEW DAYS AS FAR AS TRYING TO "PINPOINT" PRECIP CHANCES/COVERAGE MORE THAN A FEW HOURS IN ADVANCE. THE FIRST ROUND OF MODEST...MUCH- NEEDED RAINFALL OF MAINLY 0.20-0.60-INCH THAT TARGETED MAINLY THE WESTERN CWA OVERNIGHT HAS FADED AWAY/LIFTED NORTH...LEAVING IN ITS WAKE A SIZABLE AREA OF ONLY SPOTTY LIGHT SHOWERS/PATCHY DRIZZLE AND EVEN SOME LEGITIMATE MAINLY LIGHT FOG MAINLY OVER WEST- CENTRAL ZONES. GENERALLY...HERE ARE THE EXPECTATIONS FOR THE NEXT 12 HOURS OR SO: BASED ON LATEST TRENDS IN SHORT TERM MODELS SUCH AS RAP/HRRR AND 4KM WRF...THE LACK OF LARGE-SCALE FORCING AND CURRENT LIMITED INSTABILITY...THE MAJORITY OF THE CWA SHOULD MAKE IT THROUGH THE MID-LATE AFTERNOON HOURS WITH NOTHING MORE THAN A PASSING LIGHT SHOWER/SPOTTY DRIZZLE. HOWEVER...AS THE NEXT BATCH OF MODEST MID LEVEL SHORTWAVE ENERGY KICKS NORTHEAST OUT OF THE NORTHEAST PERIPHERY OF THE PARENT CLOSED LOW CENTERED WELL-SOUTHWEST NEAR THE 4-CORNERS...GRADUAL DESTABILIZATION SHOULD LEAD TO INCREASING COVERAGE OF SHOWERS/THUNDERSTORMS THROUGH THE LATE AFTERNOON AND ESPECIALLY EVENING. INITIALLY...THE GREATEST COVERAGE AND THREAT FOR STRONG STORMS/ISOLATED SEVERE WEATHER LOCALLY SHOULD TARGET THE SOUTHWEST 1/3 OF THE CWA...BUT ESPECIALLY KS ZONES. HOWEVER...THE "MAIN SHOW" FOR A GREATER RISK OF SEVERE STORMS ON THE REGIONAL SCALE SHOULD LARGELY FOCUS JUST OUTSIDE THE CWA TO THE SOUTH AND WEST WITHIN WEST-CENTRAL/SOUTHWEST KS...WHERE THE PRIMARY SPC SLIGHT/ENHANCED RISK AREAS ARE FOCUSED. WITH INSTABILITY EVEN WITHIN SOUTHERN PORTIONS OF THE LOCAL AREA (BOTH LOW-LEVEL AND ELEVATED) CURRENTLY EXPECTED TO ONLY REACH UP TO AROUND 1000 J/KG IN THE PRESENCE OF DEEP LAYER SHEAR AROUND 30-40KT...COULD EASILY SEE A MIX OF MULTICELL AND SEMI-ORGANIZED SUPERCELL STRUCTURES...WITH LOW-END SEVERE HAIL/WIND CLEARLY THE MAIN THREATS. WITH LOW-LEVEL EASTERLY FLOW...FAIRLY LOW LCL HEIGHTS AND VARIOUS MESOSCALE INTERACTIONS POSSIBLE...AT LEAST A BRIEF LATE AFTERNOON-EVENING TORNADO IS NOT COMPLETELY OUT OF THE QUESTION IN SOUTHERN ZONES...BUT AGREE WITH SPC THAT THIS PROBABILITY IS QUITE LIMITED/MAINLY 2 PERCENT AT MOST...AND THUS WILL REFRAIN FROM EVEN MENTIONING A TORNADO RISK IN THE HAZARDOUS WEATHER OUTLOOK UNLESS LATER TRENDS SUGGEST OTHERWISE. WHILE THE MAIN OPPORTUNITY FOR POSSIBLE SEVERE STORMS WILL LIKELY FOCUS DURING THE TYPICAL 4PM- MIDNIGHT TIME FRAME...AT LEAST A FEW STRONGER STORMS COULD LINGER /RE-DEVELOP WELL INTO THE NIGHT...POSSIBLY IN 1 OR MORE ROUNDS. OF COURSE...TIMING THESE INDIVIDUAL ROUNDS OF CONVECTION AND THE ASSOCIATED BREAKS IN BETWEEN WILL BE VERY DIFFICULT. ON A POSITIVE NOTE...THINK A DECENT CHUNK OF THE CWA WILL PROBABLY SEE NEW RAINFALL AMOUNTS OF 0.50-1.00" (AND LOCALLY HIGHER) BY SUNRISE FRIDAY...ESPECIALLY SOUTHERN/WESTERN ZONES. TEMP-WISE TODAY...WHILE MOSTLY CLOUDY SKIES SHOULD REMAIN IN PLACE MOST AREAS...THERE HAVE ALREADY BEEN DECENT BREAKS IN OVERCAST IN SOUTHWESTERN ZONES...WHICH HAVE THE BEST CHANCE OF POSSIBLY BREACHING 70. MEANWHILE...MOST OF THE CWA (ESPECIALLY IN NEBRASKA) IS STILL EXPECTED TO TOP OUT SOMEWHERE IN THE 60S...ALBEIT BARELY-SO IN SOME SPOTS. MORE TO COME WITH MAIN AFTERNOON DISCUSSION... && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 412 AM CDT THU APR 16 2015 RADAR SHOWS SHOWERS AND THUNDERSTORMS MOVING NORTH/NORTHEAST WITH DEVELOPMENT ON THE SOUTH END OF THE MAIN CLUSTER OF THUNDERSTORMS. SURFACE ANALYSIS SHOWS A LOW PRESSURE SYSTEM ACROSS WESTERN KANSAS WITH A COLD FRONT EXTENDING TO THE NORTH ACROSS NEBRASKA. AN UPPER LEVEL LOW IN THE IN THE FOUR CORNERS REGION WILL DRIFT TOWARD THE EAST TODAY AND TONIGHT. IN ADVANCE OF THE UPPER LOW A FEW WAVES WILL MOVE ACROSS THE AREA THROUGH TONIGHT. THE NAM AND GFS BOTH SPREAD THE PRECIPITATION ACROSS THE FORECAST AREA THROUGH THE MORNING HOURS AS THE FIRST OF THE WAVES MOVE THROUGH THE FORECAST AREA. THE RAP AND THE 4KM WRF BOTH INDICATE THIS INITIAL GROUP OF THUNDERSTORMS WILL MOVE THROUGH AND ALTHOUGH THERE MAY BE SOME ISOLATED THUNDERSTORMS AROUND...THERE COULD BE A BREAK THIS MORNING. HAVE KEPT POPS ACROSS THE AREA...BUT DID LOWER THEM A BIT THIS MORNING. THE NEXT WAVE WILL MOVE INTO THE AREA THIS AFTERNOON AND EVENING. THUNDERSTORMS SHOULD DEVELOP IN WESTERN KANSAS AND SPREAD INTO THE AREA DURING THE AFTERNOON. LATE AFTERNOON INTO THE EARLY EVENING THE MUCAPE INCREASES TO NEARLY 2500 J/KG MAINLY ACROSS KANSAS. THIS IS THE AREA WITH THE BEST CHANCE FOR SOME SEVERE WEATHER. ANOTHER UPPER LEVEL WAVE PUSHES INTO THE AREA LATE TONIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE AREA LATE TONIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 412 AM CDT THU APR 16 2015 A PAIR OF UPPER LEVEL LOWS FORECAST TO TRACK ACROSS THE SOUTHERN HALF OF THE COUNTRY WILL BRING SOME SIGNIFICANT CHANCES FOR BENEFICIAL RAINFALL TO THE REGION OVER THE NEXT WEEK OR SO. THE FIRST OF THESE LOW PRESSURE SYSTEMS IS CURRENTLY SPINNING ACROSS THE DESERT SOUTHWEST...AND ALREADY HAVING AN IMPACT ON THE LOCAL WEATHER. WITH THIS LOW CUT OFF FROM THE MAIN UPPER LEVEL FLOW ACROSS CANADA...EXPECT VERY SLOW PROGRESSION TOWARDS THE EAST TO RESULT IN MULTIPLE DAYS OF UNSETTLED WEATHER ACROSS THE REGION. WITH MOIST SOUTHERLY FLOW AHEAD OF THIS SYSTEM...DEWPOINTS HAVE SURGED INTO THE 50S ACROSS MUCH OF THE LOCAL AREA AND EXPECT THE ASSOCIATED INSTABILITY TO HELP AID IN THE FORMATION OF THUNDERSTORMS BOTH FRIDAY AND SATURDAY. THAT SAID...WITH MUCH BETTER SHEAR TO WORK WITH ON FRIDAY AFTERNOON/EVENING...THIS APPEARS TO BE THE BEST SHOT FOR MORE WIDESPREAD STRONG AND POTENTIALLY SEVERE STORMS ACROSS THE REGION...AND NOT SURPRISINGLY ROUGHLY THE SOUTHERN HALF OF THE FORECAST AREA IS NOW OUTLOOKED BY SPC. IF REALIZED...THE MAIN HAZARDS ARE LIKELY TO BE LARGE HAIL AND STRONG WIND GUSTS. WHILE STILL NOT OUT OF THE QUESTION FOR SATURDAY...ADDITIONAL STRONG TO MARGINALLY SEVERE THUNDERSTORMS WILL BE POSSIBLE DURING THE AFTERNOON AND EVENING HOURS...BUT DUE TO DIMINISHED SHEAR VALUES...THINK THE COVERAGE OF THESE STRONGER STORMS WILL BE MUCH MORE LIMITED. EVEN SO...WIDESPREAD BENEFICIAL RAINFALL IS ANTICIPATED FOR THE ENTIRE REGION BOTH DAYS...WITH STORM TOTAL PRECIPITATION AMOUNTS OVER 2 INCHES EXPECTED TO BE FAIRLY WIDESPREAD BY THE TIME THE RAINFALL ENDS AND THE RESPONSIBLE LOW PRESSURE SYSTEM TRACKS EASTWARDS SUNDAY AFTERNOON. THIS LOW PRESSURE SYSTEM WILL BE SHIFTED EASTWARD BY A FAIRLY STRONG COLD FRONT FORECAST TO DROP SOUTH ACROSS THE LOCAL AREA SUNDAY. THIS COLD FRONT WILL BRING SIGNIFICANTLY COOLER TEMPERATURES TO START THE NEW WORK WEEK WITH POTENTIALLY SOME NEAR FREEZING TEMPERATURES CURRENTLY FORECAST FOR BOTH MONDAY AND TUESDAY MORNINGS. WHILE ACTUAL FROST MAY NOT DEVELOP EITHER DAY...THESE COOLER TEMPERATURES WILL BE SOMETHING TO MONITOR AS SENSITIVE VEGETATION MAY BE IMPACTED. ADDITIONALLY...WITH STRONG NORTHWESTERLY WINDS BEHIND THIS FRONT AND DRIER AIR ADVECTING IN FROM THE NORTH...COULD EVENTUALLY SEE SOME NEAR CRITICAL FIRE WEATHER CONDITIONS REALIZED ACROSS ROUGHLY THE NORTHWESTERN HALF OF THE LOCAL AREA. BECAUSE BOTH OF THESE POTENTIAL HAZARDS ARE STILL SEVERAL DAYS OUT AND MARGINAL...OPTED NOT TO MENTION EITHER OF THESE IN THE MORNING HWO. THEREAFTER...RAINFALL CHANCES WILL INCREASE MIDWEEK AS ANOTHER UPPER LEVEL LOW MOVES INTO THE DESERT SOUTHWEST AND MOISTURE INCREASES ACROSS THE REGION. && .AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z FRIDAY) ISSUED AT 1215 PM CDT THU APR 16 2015 THIS WILL A RATHER CHALLENGING PERIOD REGARDING CEILING/VISIBILITY TRENDS AND ALSO SHOWER/THUNDERSTORM COVERAGE...AND MODIFICATIONS TO THESE ELEMENTS IN UPCOMING TAF ISSUANCES BOTH ROUTINE ISSUANCE AND AMENDMENTS ARE LIKELY. BEAR WITH US... IN GENERAL HOWEVER...AM EXPECTING CURRENT SUB-VFR CEILINGS AND PATCHY DRIZZLE RIGHT AWAY EARLY THIS AFTERNOON TO LIFT INTO LOW- END VFR AT SOME POINT THIS AFTERNOON. WHILE AN MVFR/IFR CEILING CANNOT BE RULED OUT RETURNING AT SOME POINT THIS EVENING/TONIGHT...WILL HOLD OFF ON THIS MENTION UNTIL THE LATTER HALF OF THE PERIOD FOR NOW. AS FOR SHOWER/THUNDERSTORM CHANCES...WHILE PRECIPITATION IS LIKELY ESPECIALLY TONIGHT AT THE TERMINALS...DO NOT YET HAVE THE CONFIDENCE TO ADVERTISE PREVAILING SHOWERS/THUNDERSTORMS DURING ANY GIVEN TIME FRAME...AND THUS WILL CONTINUE TO CARRY EITHER A VICINITY SHOWER (VCSH)/VICINITY THUNDERSTORM (VCTS) MENTION UNTIL SOMETHING TRULY SHOWS ITS HAND. FORTUNATELY...SURFACE WIND TRENDS SEEM REASONABLY STRAIGHTFORWARD (OUTSIDE OF ANY CONVECTIVE ENHANCEMENT/MODIFICATION OF COURSE)...WITH A GENERALLY EASTERLY DIRECTION PRIMARILY UNDER 12KT IN PLACE THE MAJORITY OF THE TIME. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...PFANNKUCH SHORT TERM...JCB LONG TERM...ROSSI AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
807 AM CDT THU APR 16 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 412 AM CDT THU APR 16 2015 RADAR SHOWS SHOWERS AND THUNDERSTORMS MOVING NORTH/NORTHEAST WITH DEVELOPMENT ON THE SOUTH END OF THE MAIN CLUSTER OF THUNDERSTORMS. SURFACE ANALYSIS SHOWS A LOW PRESSURE SYSTEM ACROSS WESTERN KANSAS WITH A COLD FRONT EXTENDING TO THE NORTH ACROSS NEBRASKA. AN UPPER LEVEL LOW IN THE IN THE FOUR CORNERS REGION WILL DRIFT TOWARD THE EAST TODAY AND TONIGHT. IN ADVANCE OF THE UPPER LOW A FEW WAVES WILL MOVE ACROSS THE AREA THROUGH TONIGHT. THE NAM AND GFS BOTH SPREAD THE PRECIPITATION ACROSS THE FORECAST AREA THROUGH THE MORNING HOURS AS THE FIRST OF THE WAVES MOVE THROUGH THE FORECAST AREA. THE RAP AND THE 4KM WRF BOTH INDICATE THIS INITIAL GROUP OF THUNDERSTORMS WILL MOVE THROUGH AND ALTHOUGH THERE MAY BE SOME ISOLATED THUNDERSTORMS AROUND...THERE COULD BE A BREAK THIS MORNING. HAVE KEPT POPS ACROSS THE AREA...BUT DID LOWER THEM A BIT THIS MORNING. THE NEXT WAVE WILL MOVE INTO THE AREA THIS AFTERNOON AND EVENING. THUNDERSTORMS SHOULD DEVELOP IN WESTERN KANSAS AND SPREAD INTO THE AREA DURING THE AFTERNOON. LATE AFTERNOON INTO THE EARLY EVENING THE MUCAPE INCREASES TO NEARLY 2500 J/KG MAINLY ACROSS KANSAS. THIS IS THE AREA WITH THE BEST CHANCE FOR SOME SEVERE WEATHER. ANOTHER UPPER LEVEL WAVE PUSHES INTO THE AREA LATE TONIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE AREA LATE TONIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 412 AM CDT THU APR 16 2015 A PAIR OF UPPER LEVEL LOWS FORECAST TO TRACK ACROSS THE SOUTHERN HALF OF THE COUNTRY WILL BRING SOME SIGNIFICANT CHANCES FOR BENEFICIAL RAINFALL TO THE REGION OVER THE NEXT WEEK OR SO. THE FIRST OF THESE LOW PRESSURE SYSTEMS IS CURRENTLY SPINNING ACROSS THE DESERT SOUTHWEST...AND ALREADY HAVING AN IMPACT ON THE LOCAL WEATHER. WITH THIS LOW CUT OFF FROM THE MAIN UPPER LEVEL FLOW ACROSS CANADA...EXPECT VERY SLOW PROGRESSION TOWARDS THE EAST TO RESULT IN MULTIPLE DAYS OF UNSETTLED WEATHER ACROSS THE REGION. WITH MOIST SOUTHERLY FLOW AHEAD OF THIS SYSTEM...DEWPOINTS HAVE SURGED INTO THE 50S ACROSS MUCH OF THE LOCAL AREA AND EXPECT THE ASSOCIATED INSTABILITY TO HELP AID IN THE FORMATION OF THUNDERSTORMS BOTH FRIDAY AND SATURDAY. THAT SAID...WITH MUCH BETTER SHEAR TO WORK WITH ON FRIDAY AFTERNOON/EVENING...THIS APPEARS TO BE THE BEST SHOT FOR MORE WIDESPREAD STRONG AND POTENTIALLY SEVERE STORMS ACROSS THE REGION...AND NOT SURPRISINGLY ROUGHLY THE SOUTHERN HALF OF THE FORECAST AREA IS NOW OUTLOOKED BY SPC. IF REALIZED...THE MAIN HAZARDS ARE LIKELY TO BE LARGE HAIL AND STRONG WIND GUSTS. WHILE STILL NOT OUT OF THE QUESTION FOR SATURDAY...ADDITIONAL STRONG TO MARGINALLY SEVERE THUNDERSTORMS WILL BE POSSIBLE DURING THE AFTERNOON AND EVENING HOURS...BUT DUE TO DIMINISHED SHEAR VALUES...THINK THE COVERAGE OF THESE STRONGER STORMS WILL BE MUCH MORE LIMITED. EVEN SO...WIDESPREAD BENEFICIAL RAINFALL IS ANTICIPATED FOR THE ENTIRE REGION BOTH DAYS...WITH STORM TOTAL PRECIPITATION AMOUNTS OVER 2 INCHES EXPECTED TO BE FAIRLY WIDESPREAD BY THE TIME THE RAINFALL ENDS AND THE RESPONSIBLE LOW PRESSURE SYSTEM TRACKS EASTWARDS SUNDAY AFTERNOON. THIS LOW PRESSURE SYSTEM WILL BE SHIFTED EASTWARD BY A FAIRLY STRONG COLD FRONT FORECAST TO DROP SOUTH ACROSS THE LOCAL AREA SUNDAY. THIS COLD FRONT WILL BRING SIGNIFICANTLY COOLER TEMPERATURES TO START THE NEW WORK WEEK WITH POTENTIALLY SOME NEAR FREEZING TEMPERATURES CURRENTLY FORECAST FOR BOTH MONDAY AND TUESDAY MORNINGS. WHILE ACTUAL FROST MAY NOT DEVELOP EITHER DAY...THESE COOLER TEMPERATURES WILL BE SOMETHING TO MONITOR AS SENSITIVE VEGETATION MAY BE IMPACTED. ADDITIONALLY...WITH STRONG NORTHWESTERLY WINDS BEHIND THIS FRONT AND DRIER AIR ADVECTING IN FROM THE NORTH...COULD EVENTUALLY SEE SOME NEAR CRITICAL FIRE WEATHER CONDITIONS REALIZED ACROSS ROUGHLY THE NORTHWESTERN HALF OF THE LOCAL AREA. BECAUSE BOTH OF THESE POTENTIAL HAZARDS ARE STILL SEVERAL DAYS OUT AND MARGINAL...OPTED NOT TO MENTION EITHER OF THESE IN THE MORNING HWO. THEREAFTER...RAINFALL CHANCES WILL INCREASE MIDWEEK AS ANOTHER UPPER LEVEL LOW MOVES INTO THE DESERT SOUTHWEST AND MOISTURE INCREASES ACROSS THE REGION. && .AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 806 AM CDT THU APR 16 2015 ...UPDATE TO 12Z TAF DISCUSSION... SINCE THE PREVIOUS DISCUSSION WAS ISSUED A FEW HOURS AGO...AVIATION CONDITIONS HAVE TAKEN A NOTABLE DOWNWARD TURN WITH PREVAILING LIFR/IFR CEILING AND IFR/MVFR VISIBILITY IN LOW STRATUS/LIGHT FOG. THERE IS LIKELY EVEN SOME OFF-AND-ON LIGHT DRIZZLE ONGOING. IN SHORT...EXPECT A GRADUAL IMPROVEMENT IN CEILING/VISIBILITY AS THE DAY WEARS ON...BUT SUB-VFR CONDITIONS MAY LAST LONGER (ESPECIALLY CEILING-WISE) THAN EARLIER THOUGHT. PRECIPITATION-WISE...THE FIRST 12-15 HOURS SHOULD MAINLY FEATURE SPOTTY LIGHT SHOWERS/DRIZZLE...WITH A BETTER CHANCE OF ORGANIZED THUNDERSTORM ACTIVITY ARRIVING THIS EVENING INTO TONIGHT. IN CLOSING...ANTICIPATE AMENDMENTS TO BE NECESSARY DURING THE PERIOD AS WE GRADUALLY GET A HANDLE ON SHORT-TERM TRENDS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...JCB LONG TERM...ROSSI AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
548 AM CDT THU APR 16 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 412 AM CDT THU APR 16 2015 RADAR SHOWS SHOWERS AND THUNDERSTORMS MOVING NORTH/NORTHEAST WITH DEVELOPMENT ON THE SOUTH END OF THE MAIN CLUSTER OF THUNDERSTORMS. SURFACE ANALYSIS SHOWS A LOW PRESSURE SYSTEM ACROSS WESTERN KANSAS WITH A COLD FRONT EXTENDING TO THE NORTH ACROSS NEBRASKA. AN UPPER LEVEL LOW IN THE IN THE FOUR CORNERS REGION WILL DRIFT TOWARD THE EAST TODAY AND TONIGHT. IN ADVANCE OF THE UPPER LOW A FEW WAVES WILL MOVE ACROSS THE AREA THROUGH TONIGHT. THE NAM AND GFS BOTH SPREAD THE PRECIPITATION ACROSS THE FORECAST AREA THROUGH THE MORNING HOURS AS THE FIRST OF THE WAVES MOVE THROUGH THE FORECAST AREA. THE RAP AND THE 4KM WRF BOTH INDICATE THIS INITIAL GROUP OF THUNDERSTORMS WILL MOVE THROUGH AND ALTHOUGH THERE MAY BE SOME ISOLATED THUNDERSTORMS AROUND...THERE COULD BE A BREAK THIS MORNING. HAVE KEPT POPS ACROSS THE AREA...BUT DID LOWER THEM A BIT THIS MORNING. THE NEXT WAVE WILL MOVE INTO THE AREA THIS AFTERNOON AND EVENING. THUNDERSTORMS SHOULD DEVELOP IN WESTERN KANSAS AND SPREAD INTO THE AREA DURING THE AFTERNOON. LATE AFTERNOON INTO THE EARLY EVENING THE MUCAPE INCREASES TO NEARLY 2500 J/KG MAINLY ACROSS KANSAS. THIS IS THE AREA WITH THE BEST CHANCE FOR SOME SEVERE WEATHER. ANOTHER UPPER LEVEL WAVE PUSHES INTO THE AREA LATE TONIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE AREA LATE TONIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 412 AM CDT THU APR 16 2015 A PAIR OF UPPER LEVEL LOWS FORECAST TO TRACK ACROSS THE SOUTHERN HALF OF THE COUNTRY WILL BRING SOME SIGNIFICANT CHANCES FOR BENEFICIAL RAINFALL TO THE REGION OVER THE NEXT WEEK OR SO. THE FIRST OF THESE LOW PRESSURE SYSTEMS IS CURRENTLY SPINNING ACROSS THE DESERT SOUTHWEST...AND ALREADY HAVING AN IMPACT ON THE LOCAL WEATHER. WITH THIS LOW CUT OFF FROM THE MAIN UPPER LEVEL FLOW ACROSS CANADA...EXPECT VERY SLOW PROGRESSION TOWARDS THE EAST TO RESULT IN MULTIPLE DAYS OF UNSETTLED WEATHER ACROSS THE REGION. WITH MOIST SOUTHERLY FLOW AHEAD OF THIS SYSTEM...DEWPOINTS HAVE SURGED INTO THE 50S ACROSS MUCH OF THE LOCAL AREA AND EXPECT THE ASSOCIATED INSTABILITY TO HELP AID IN THE FORMATION OF THUNDERSTORMS BOTH FRIDAY AND SATURDAY. THAT SAID...WITH MUCH BETTER SHEAR TO WORK WITH ON FRIDAY AFTERNOON/EVENING...THIS APPEARS TO BE THE BEST SHOT FOR MORE WIDESPREAD STRONG AND POTENTIALLY SEVERE STORMS ACROSS THE REGION...AND NOT SURPRISINGLY ROUGHLY THE SOUTHERN HALF OF THE FORECAST AREA IS NOW OUTLOOKED BY SPC. IF REALIZED...THE MAIN HAZARDS ARE LIKELY TO BE LARGE HAIL AND STRONG WIND GUSTS. WHILE STILL NOT OUT OF THE QUESTION FOR SATURDAY...ADDITIONAL STRONG TO MARGINALLY SEVERE THUNDERSTORMS WILL BE POSSIBLE DURING THE AFTERNOON AND EVENING HOURS...BUT DUE TO DIMINISHED SHEAR VALUES...THINK THE COVERAGE OF THESE STRONGER STORMS WILL BE MUCH MORE LIMITED. EVEN SO...WIDESPREAD BENEFICIAL RAINFALL IS ANTICIPATED FOR THE ENTIRE REGION BOTH DAYS...WITH STORM TOTAL PRECIPITATION AMOUNTS OVER 2 INCHES EXPECTED TO BE FAIRLY WIDESPREAD BY THE TIME THE RAINFALL ENDS AND THE RESPONSIBLE LOW PRESSURE SYSTEM TRACKS EASTWARDS SUNDAY AFTERNOON. THIS LOW PRESSURE SYSTEM WILL BE SHIFTED EASTWARD BY A FAIRLY STRONG COLD FRONT FORECAST TO DROP SOUTH ACROSS THE LOCAL AREA SUNDAY. THIS COLD FRONT WILL BRING SIGNIFICANTLY COOLER TEMPERATURES TO START THE NEW WORK WEEK WITH POTENTIALLY SOME NEAR FREEZING TEMPERATURES CURRENTLY FORECAST FOR BOTH MONDAY AND TUESDAY MORNINGS. WHILE ACTUAL FROST MAY NOT DEVELOP EITHER DAY...THESE COOLER TEMPERATURES WILL BE SOMETHING TO MONITOR AS SENSITIVE VEGETATION MAY BE IMPACTED. ADDITIONALLY...WITH STRONG NORTHWESTERLY WINDS BEHIND THIS FRONT AND DRIER AIR ADVECTING IN FROM THE NORTH...COULD EVENTUALLY SEE SOME NEAR CRITICAL FIRE WEATHER CONDITIONS REALIZED ACROSS ROUGHLY THE NORTHWESTERN HALF OF THE LOCAL AREA. BECAUSE BOTH OF THESE POTENTIAL HAZARDS ARE STILL SEVERAL DAYS OUT AND MARGINAL...OPTED NOT TO MENTION EITHER OF THESE IN THE MORNING HWO. THEREAFTER...RAINFALL CHANCES WILL INCREASE MIDWEEK AS ANOTHER UPPER LEVEL LOW MOVES INTO THE DESERT SOUTHWEST AND MOISTURE INCREASES ACROSS THE REGION. && .AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 546 AM CDT THU APR 16 2015 THUNDERSTORMS HAVE MOVED TO THE NORTH OF THE TERMINAL AREAS. THERE COULD BE A SPRINKLE OR TWO FOR A WHILE BUT THEN THERE COULD BE A BREAK. THUNDERSTORMS ARE EXPECTED TO REDEVELOP LATER THIS MORNING OR EARLY THIS AFTERNOON. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...JCB LONG TERM...ROSSI AVIATION...JCB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
415 AM CDT THU APR 16 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 412 AM CDT THU APR 16 2015 RADAR SHOWS SHOWERS AND THUNDERSTORMS MOVING NORTH/NORTHEAST WITH DEVELOPMENT ON THE SOUTH END OF THE MAIN CLUSTER OF THUNDERSTORMS. SURFACE ANALYSIS SHOWS A LOW PRESSURE SYSTEM ACROSS WESTERN KANSAS WITH A COLD FRONT EXTENDING TO THE NORTH ACROSS NEBRASKA. AN UPPER LEVEL LOW IN THE IN THE FOUR CORNERS REGION WILL DRIFT TOWARD THE EAST TODAY AND TONIGHT. IN ADVANCE OF THE UPPER LOW A FEW WAVES WILL MOVE ACROSS THE AREA THROUGH TONIGHT. THE NAM AND GFS BOTH SPREAD THE PRECIPITATION ACROSS THE FORECAST AREA THROUGH THE MORNING HOURS AS THE FIRST OF THE WAVES MOVE THROUGH THE FORECAST AREA. THE RAP AND THE 4KM WRF BOTH INDICATE THIS INITIAL GROUP OF THUNDERSTORMS WILL MOVE THROUGH AND ALTHOUGH THERE MAY BE SOME ISOLATED THUNDERSTORMS AROUND...THERE COULD BE A BREAK THIS MORNING. HAVE KEPT POPS ACROSS THE AREA...BUT DID LOWER THEM A BIT THIS MORNING. THE NEXT WAVE WILL MOVE INTO THE AREA THIS AFTERNOON AND EVENING. THUNDERSTORMS SHOULD DEVELOP IN WESTERN KANSAS AND SPREAD INTO THE AREA DURING THE AFTERNOON. LATE AFTERNOON INTO THE EARLY EVENING THE MUCAPE INCREASES TO NEARLY 2500 J/KG MAINLY ACROSS KANSAS. THIS IS THE AREA WITH THE BEST CHANCE FOR SOME SEVERE WEATHER. ANOTHER UPPER LEVEL WAVE PUSHES INTO THE AREA LATE TONIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE AREA LATE TONIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 412 AM CDT THU APR 16 2015 A PAIR OF UPPER LEVEL LOWS FORECAST TO TRACK ACROSS THE SOUTHERN HALF OF THE COUNTRY WILL BRING SOME SIGNIFICANT CHANCES FOR BENEFICIAL RAINFALL TO THE REGION OVER THE NEXT WEEK OR SO. THE FIRST OF THESE LOW PRESSURE SYSTEMS IS CURRENTLY SPINNING ACROSS THE DESERT SOUTHWEST...AND ALREADY HAVING AN IMPACT ON THE LOCAL WEATHER. WITH THIS LOW CUT OFF FROM THE MAIN UPPER LEVEL FLOW ACROSS CANADA...EXPECT VERY SLOW PROGRESSION TOWARDS THE EAST TO RESULT IN MULTIPLE DAYS OF UNSETTLED WEATHER ACROSS THE REGION. WITH MOIST SOUTHERLY FLOW AHEAD OF THIS SYSTEM...DEWPOINTS HAVE SURGED INTO THE 50S ACROSS MUCH OF THE LOCAL AREA AND EXPECT THE ASSOCIATED INSTABILITY TO HELP AID IN THE FORMATION OF THUNDERSTORMS BOTH FRIDAY AND SATURDAY. THAT SAID...WITH MUCH BETTER SHEAR TO WORK WITH ON FRIDAY AFTERNOON/EVENING...THIS APPEARS TO BE THE BEST SHOT FOR MORE WIDESPREAD STRONG AND POTENTIALLY SEVERE STORMS ACROSS THE REGION...AND NOT SURPRISINGLY ROUGHLY THE SOUTHERN HALF OF THE FORECAST AREA IS NOW OUTLOOKED BY SPC. IF REALIZED...THE MAIN HAZARDS ARE LIKELY TO BE LARGE HAIL AND STRONG WIND GUSTS. WHILE STILL NOT OUT OF THE QUESTION FOR SATURDAY...ADDITIONAL STRONG TO MARGINALLY SEVERE THUNDERSTORMS WILL BE POSSIBLE DURING THE AFTERNOON AND EVENING HOURS...BUT DUE TO DIMINISHED SHEAR VALUES...THINK THE COVERAGE OF THESE STRONGER STORMS WILL BE MUCH MORE LIMITED. EVEN SO...WIDESPREAD BENEFICIAL RAINFALL IS ANTICIPATED FOR THE ENTIRE REGION BOTH DAYS...WITH STORM TOTAL PRECIPITATION AMOUNTS OVER 2 INCHES EXPECTED TO BE FAIRLY WIDESPREAD BY THE TIME THE RAINFALL ENDS AND THE RESPONSIBLE LOW PRESSURE SYSTEM TRACKS EASTWARDS SUNDAY AFTERNOON. THIS LOW PRESSURE SYSTEM WILL BE SHIFTED EASTWARD BY A FAIRLY STRONG COLD FRONT FORECAST TO DROP SOUTH ACROSS THE LOCAL AREA SUNDAY. THIS COLD FRONT WILL BRING SIGNIFICANTLY COOLER TEMPERATURES TO START THE NEW WORK WEEK WITH POTENTIALLY SOME NEAR FREEZING TEMPERATURES CURRENTLY FORECAST FOR BOTH MONDAY AND TUESDAY MORNINGS. WHILE ACTUAL FROST MAY NOT DEVELOP EITHER DAY...THESE COOLER TEMPERATURES WILL BE SOMETHING TO MONITOR AS SENSITIVE VEGETATION MAY BE IMPACTED. ADDITIONALLY...WITH STRONG NORTHWESTERLY WINDS BEHIND THIS FRONT AND DRIER AIR ADVECTING IN FROM THE NORTH...COULD EVENTUALLY SEE SOME NEAR CRITICAL FIRE WEATHER CONDITIONS REALIZED ACROSS ROUGHLY THE NORTHWESTERN HALF OF THE LOCAL AREA. BECAUSE BOTH OF THESE POTENTIAL HAZARDS ARE STILL SEVERAL DAYS OUT AND MARGINAL...OPTED NOT TO MENTION EITHER OF THESE IN THE MORNING HWO. THEREAFTER...RAINFALL CHANCES WILL INCREASE MIDWEEK AS ANOTHER UPPER LEVEL LOW MOVES INTO THE DESERT SOUTHWEST AND MOISTURE INCREASES ACROSS THE REGION. && .AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1225 AM CDT THU APR 16 2015 THUNDERSTORMS ARE GRADUALLY MOVING IN FROM THE WEST. THUNDERSTORMS ARE EXPECTED ON AND OFF THROUGH MUCH OF THE DAY. THE SURFACE LOW TO THE SOUTHWEST WILL KEEP WINDS FROM THE EAST OR SOUTHEAST THROUGH THE PERIOD. THE LOWEST CEILINGS WILL BE BEFORE SUNRISE THIS MORNING. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...JCB LONG TERM...ROSSI AVIATION...JCB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1150 PM CDT WED APR 15 2015 .SHORT TERM...(TONIGHT) ISSUED AT 309 PM CDT WED APR 15 2015 LARGE SCALE PATTERN PER WV IMAGERY THIS AFTN SHOWING FAST ZONAL FLOW WITH SEVERAL EMBEDDED WAVES EXTENDING ACROSS SRN CANADA WITH A LARGE CLOSED OFF CIRCULATION SITUATED OVER THE GREAT BASIN. AT THE SFC...LLVL MOISTURE RETURN IS UNDERWAY WITH DEW POINTS INCREASING OVER THE LOWER/MID MS VLY REGION. RUC13 SHOWING BNDRY LYR MOISTURE ADV CONTINUING THRU TONIGHT WITH PW VALUES INCREASING TO AROUND AN INCH OVER THE CWA. TSTM DEVELOPMENT PROGGED TO OCCUR OVER CNTRL KS/S- CNTRL NEB LATER THIS EVENING WITHIN AREA OF ELEVATED INSTABILITY/NOSE OF LLVL JET...THEN EXPAND NEWD INTO THE WRN CWA SOMETIME AFT MIDNIGHT AS UPGLIDE INCREASES ALONG 300K SFC. PLAN ON ONLY MAKING MINOR TWEAKS AT THIS POINT AS GOING FCST IS IN DECENT SHAPE DEPICTING POPS INCREASING FROM WEST TO EAST DURING THE OVERNIGHT HOURS. .LONG TERM...(THURSDAY THROUGH WEDNESDAY) ISSUED AT 309 PM CDT WED APR 15 2015 MAIN FORECAST CONCERN WILL BE PROGRESSION OF WESTERN CONUS UPPER LOW AND ITS IMPACTS AS IT SLIDE ACROSS THE CENTRAL PLAINS. BY THURSDAY MORNING...THE WESTERN CONUS UPPER LOW WILL BE CENTERED ON TOP OF THE FOUR CORNERS REGION. LEE SIDE SFC LOW REFLECTION IS FORECAST TO BE FAIRLY BROAD ACROSS THE TEXAS PANHANDLE WITH AN INVERTED TROUGH EXTENDING NORTHEAST ACROSS WESTERN KS AND INTO WESTERN NEBRASKA. PRECIPITATION WILL CONTINUE TO SPREAD EAST INTO OUR WESTERN CWA...BECOMING LIKELY LATER IN THE DAY THURSDAY AS BROAD SCALE ASCENT INCREASES WITH LEAD SHORTWAVE ENERGY. THE UPPER LOW WILL SLOWLY MOVE INTO THE SOUTHERN PLAINS AND IS FORECAST TO OPEN UP THROUGH THE WEEKEND PROVIDING CONTINUED BROAD SCALE VERTICAL MOTION THROUGH SUNDAY. LOW LEVEL MOISTURE ALREADY IN PLACE ACROSS THE SOUTHERN PLAINS WILL CONTINUE TO STREAM NORTHWARD AS THE SFC LOW PRESSURE CENTER BETTER ORGANIZES ACROSS EASTERN COLORADO BY FRIDAY MORNING. PW`S WILL REMAIN ABOVE 1" THROUGH THE PERIOD. ALTHOUGH RAIN IS LIKELY AT TIMES THROUGH SUNDAY...WE WILL HAVE A FEW INTERMITTENT BREAKS BUT TOO DIFFICULT TO DETERMINE AT THIS POINT WITH SUCH SLOW PROGRESSION OF THE UPPER LOW. BEST CHANCE FOR THUNDERSTORMS LOOKS TO BE THURSDAY AND FRIDAY AFTERNOON...ESPECIALLY ACROSS THE SOUTHERN CWA. HAVE INCLUDED ISOLATED THUNDER MENTION THROUGH MUCH OF THE TIME PERIOD. BY MID DAY SUNDAY...THE UPPER TROUGH AXIS SHOULD BE EAST OF THE CWA...ALLOWING PCPN TO END FROM WEST TO EAST. THE 12Z ECMWF REALLY WRAPS THIS SYSTEM UP...WITH NORTHWESTERLY 850MB WINDS ON THE ORDER OF 65KTS SUNDAY AFTERNOON. 850MB TEMPERATURES DO APPROACH THE 0C MARK OF THE LATEST ECMWF SO WILL NEED TO WATCH THAT CAREFULLY FOR ANY CHANGE OVER IN PCPN TYPES SUNDAY. MUCH COOLER NORTHWESTERLY FLOW WILL PERSIST ACROSS THE AREA THROUGH EARLY NEXT WEEK WHICH MAY PUT TEMPERATURES INTO THE BELOW NORMAL CATEGORY. A FEW MINOR WAVES MAY MOVE THROUGH THIS FLOW PROVIDING SMALL CHANCES FOR PCPN. && .AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1146 PM CDT WED APR 15 2015 GENERALLY MVFR CIGS ARE EXPECTED OVERNIGHT AT THE TAF SITES. THE BNK-OVC DECKS SHOULD CONT THROUGH THE DAY ON THU AS WELL BUT INCREASE TO VFR /FL0040-050/ BY MID TO LATE MRNG. WE WILL CONT TO LEAVE THE TAFS DRY AT THE MOMENT AS PRECIP TIMING AND CONFIDENCE IS PRETTY LOW AT THIS POINT. IT WOULD APPEAR THAT THERE COULD BE SOME MRNG SHRA AT KLNK...AND THEN SOME ISO LATE AFTN -SHRA AT ALL SITES BUT COVERAGE IS EXPECTED TO BE LOW. OTHERWISE SOUTHEAST WINDS...GENERALLY BELOW 12 KT...WILL CONT THROUGH THU EVNG. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...DEE LONG TERM...KERN AVIATION...BOUSTEAD
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1038 PM EDT FRI APR 17 2015 .SYNOPSIS... HIGH PRESSURE WILL BRING CLEARING SKIES TONIGHT. A COLD FRONT WILL MOVE ACROSS THE REGION ON SATURDAY...HOWEVER THE FRONT IS MOISTURE STARVED SO MOST AREAS WILL REMAIN MOSTLY SUNNY AND BREEZY. A FEW SCATTERED LIGHT SHOWERS ARE POSSIBLE ACROSS THE NORTH COUNTRY WHERE A LITTLE MORE MOISTURE IS AVAILABLE. HIGH PRESSURE WILL BRING A RETURN TO DRY WEATHER FOR SUNDAY. LOW PRESSURE WILL MOVE THROUGH THE GREAT LAKES SUNDAY NIGHT AND MONDAY WITH OCCASIONAL SHOWERS AND GUSTY WINDS. UNSETTLED AND COOL WEATHER IS THEN EXPECTED MOST OF NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY/... THE 00Z BUF SOUNDINGS SHOWS A NICELY ESTABLISHED MARINE LAYER WITH A SHARP INVERSION ABOVE 700 FEET AGL. THIS INVERSION SHOULD KEEP A TIGHT CAP ON THE MARINE MOISTURE OFF THE LAKES...AND AS SOUTHWESTERLY WINDS INCREASE AGAIN LATER TONIGHT...SHOULD SUPPORT ANOTHER ROUND OF FOG FOR THE BUFFALO AND WATERTOWN AREAS AFTER MIDNIGHT. NAM/SREF/GFS BUFKIT SOUNDINGS PICK UP ON THIS INVERSION NICELY...AND SHOW SUPPORT FOR FOG DEVELOPING OVER THE LAKES AFTER MIDNIGHT AND ADVECTING INLAND. BY TOMORROW MORNING...THE APPROACHING COLD FRONT WILL GIVE THE FORCING NEEDED TO FINALLY BREAK THIS UP THIS MARINE LAYER AND SCOUR OUT ANY FOG THAT REDEVELOPS OVERNIGHT. IN FACT...THE HRRR PICKS UP NICELY ON A PERIOD OF CLEARING FOR BUFFALO THIS EVENING...BEFORE ADVECTING FOG DOWN THE LAKE AND INTO THE BUFFALO/NIAGARA FALLS AREAS ON A SOUTHWESTERLY TO SOUTH-SOUTHWESTERLY FLOW. A WEAK BUBBLE OF HIGH PRESSURE WILL BUILD INTO THE OHIO VALLEY TONIGHT WITH A RIDGE EXTENDING INTO THE LOWER LAKES. SUBSIDENCE AND DRYING ASSOCIATED WITH THIS HIGH WILL FINISH THE CLEARING PROCESS TONIGHT AND SUPPORT CLEAR SKIES OVERNIGHT. EXPECT LOWS IN THE LOWER 40S IN MOST LOCATIONS WITH MID TO UPPER 30S IN THE COOLEST SOUTHERN TIER VALLEYS AND NORTH COUNTRY. ON SATURDAY A POTENT MID LEVEL SHORTWAVE AND ASSOCIATED WEAK SURFACE LOW WILL CROSS QUEBEC AND NEW ENGLAND. A TRAILING SURFACE COLD FRONT WILL CROSS OUR REGION DURING THE LATE MORNING. DESPITE THE STRONG ASCENT WITH THE SHORTWAVE...THE FRONT WILL BE MOISTURE STARVED WITH LITTLE EVEN IN THE WAY OF CLOUD COVER FOR THE BULK OF THE AREA. THE STRONGEST FORCING AND SOMEWHAT BETTER MOISTURE WILL CLIP THE NORTH COUNTRY WHERE A FEW SPRINKLES OR LIGHT SHOWERS ARE POSSIBLE FROM MID MORNING THROUGH MID AFTERNOON ALONG WITH MORE CLOUD COVER. THE REST OF THE AREA SHOULD REMAIN MOSTLY SUNNY. NORTHWEST WINDS WILL BECOME A LITTLE GUSTY BEHIND THE COLD FRONT SATURDAY AFTERNOON...WITH GUSTS IN THE 30-35 MPH RANGE ESPECIALLY ACROSS THE HIGHER TERRAIN OF THE INTERIOR SOUTHERN TIER...FINGER LAKES...AND NORTH COUNTRY. DESPITE THE COLD FRONTAL PASSAGE...DEEP MIXING AND SUNSHINE WILL BOOST HIGHS INTO THE MID 60S IN MOST AREAS WITH UPPER 50S TO LOWER 60S NORTH COUNTRY. GRADIENT ONSHORE FLOW WILL KEEP THE LAKE ERIE AND ONTARIO SHORES COOLER. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... SATURDAY NIGHT THROUGH MOST OF SUNDAY QUIET WEATHER CONDITIONS ARE EXPECTED ACROSS THE REGION AS HIGH PRESSURE ADVANCES ACROSS SOUTHERN QUEBEC. THROUGH THE COURSE OF SUNDAY MID AND HIGH LEVEL CLOUDS WILL BE INCREASING FROM WEST TO EAST ACROSS NEW YORK STATE...THESE CLOUDS ARE IN ADVANCE OF A WARM FRONT THAT WILL BE LIFTING NORTHWARD ACROSS THE OHIO VALLEY. THIS WARM FRONT WILL BE CONNECTED TO AN AREA OF LOW PRESSURE THAT WILL LIFT NORTHWARD FROM WESTERN KENTUCKY SUNDAY TO NORTHERN MICHIGAN MONDAY MORNING. GULF MOISTURE WILL INCREASE ACROSS THE EASTERN GREAT LAKES REGION LATE SUNDAY AFTERNOON AND SUNDAY NIGHT AS THE WARM FRONT FROM THE SOUTH REACHES WESTERN NEW YORK. STRONG LOW LEVEL CONVERGENCE FROM A 65 TO 70 KNOT LLJ CENTERED NEAR 850 TO 900 HPA WILL BRING LIFT ACROSS THE WARM FRONT...SUCH THAT WIDESPREAD RAIN FALL UPON THE REGION SUNDAY NIGHT. A QUARTER TO HALF INCH OF RAINFALL IS EXPECTED SUNDAY NIGHT AND INTO MONDAY MORNING FROM THIS SYSTEM. WINDS WILL ALSO BECOME GUSTY LATER SUNDAY NIGHT ALONG THE LAKE ERIE SHORE...WHERE A SE LLJ ALOFT BRINGS SURFACE GUSTS 30 TO 40 KNOTS ALONG THE SHORELINE. AS THE WARM FRONT AND ASSOCIATED RAIN LIFTS NORTHWARD OUT OF THE REGION MONDAY...THERE IS THE POTENTIAL FOR LIMITED SUNSHINE ALONG WITH A BRIEF WINDOW OF RAINFREE CONDITIONS. WITH THE LLJ STILL OVERHEAD...ANY SUNSHINE WILL INCREASE THE MIXING HEIGHTS SUCH THAT WE COULD TAP INTO THIS LLJ...WITH WIND GUSTS MONDAY ALSO 30 TO 35 KNOTS ACROSS WESTERN AND NORTH CENTRAL NEW YORK. LATER MONDAY AFTERNOON CLOUDS WILL THICKEN FROM WEST TO EAST...AND A DECREASE IN THE GUSTY WINDS IS EXPECTED. A COLD FRONT FROM THIS CENTRAL LAKES STORM SYSTEM WILL NEAR WESTERN NEW YORK LATE MONDAY AFTERNOON. ANOTHER ROUND OF RAIN SHOWERS IS EXPECTED MONDAY AFTERNOON AND MONDAY NIGHT ALONG AND AHEAD OF THE COLD FRONT. ANOTHER RAINFALL EVENT AVERAGING AROUND A QUARTER OF AN INCH IS EXPECTED. RAINFALL VALUES MAY RANGE GREATER WITH THE COLD FRONT PASSAGE THAN THE EARLIER WARM FRONT DUE TO THE CONVECTIVE NATURE OF THE RAIN SHOWERS. MID LEVEL LAPSE RATES ARE NOT PARTICULARLY STRONG AND WITH THE OVERNIGHT PASSAGE OF THE COLD FRONT FOR NOW WILL NOT INCLUDE ANY MENTION OF THUNDER WITH THIS FORECAST PACKAGE...EVEN THROUGH THERE IS SOME SKINNY MID LEVEL CAPE. THE WARMEST DAY THIS PERIOD WILL BE MONDAY WHEN BEFORE THE COLD FRONT 850 HPA TEMPERATURES WILL SURGE TO +7 TO +10C. THESE READINGS WILL SUPPORT HIGHS IN THE 60S...WITH 70S POSSIBLE ACROSS LOWER ELEVATIONS ON A SOUTHEAST WIND. && .LONG TERM /TUESDAY THROUGH FRIDAY/... CLASSIC SPRING-TIME PATTERN THIS TIME PERIOD AS A DEVELOPING NEGATIVE NAO ALLOWS FOR A UPPER LEVEL CUT OFF LOW TO STALL OVER EASTERN CANADA AND THE NORTHEAST UNITED STATES. UNDER THIS LOW PRESSURE EXPECT CLOUDY DAYS WITH SCATTERED RAIN SHOWERS. RAIN SHOWER ACTIVITY WILL BE MOST PRONOUNCED IN THE AFTERNOON HOURS WITH DAYTIME HEATING...WITH FEW SHOWERS TO BE FOUND BY NIGHT. THERE MAY EVEN BE SOME WET SNOW MIXING IN AT NIGHT ACROSS THE REGION. DAYTIME AIR TEMPERATURES WILL AVERAGE 5 TO 10 DEGREES BELOW NORMAL. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... AFTER MIDNIGHT...MOISTURE TRAPPED UNDER A SHARP INVERSION WILL BE ENHANCED BY LAKES ERIE AND ONTARIO. SOUTHWEST TO SOUTH-SOUTHWESTERLY WINDS COULD BRING SOME AREAS OF FOG INTO THE KBUF/KIAG/KART TERMINALS...HOWEVER FORECAST CONFIDENCE IN THE INLAND EXTENT OF THIS FOG TO THE TERMINALS REMAINS LOW. OUTSIDE OF THE POTENTIAL FOR FOG...MAINLY VFR CONDITIONS WITH CLEAR SKIES AND LIGHT WINDS WILL PREVAIL ACROSS THE TAF SITES. ON SATURDAY A MOISTURE STARVED SHARP MID LEVEL DISTURBANCE AND COLD FRONT WILL CROSS THE REGION. THE STRONGEST ASCENT WILL CROSS THE NORTH COUNTRY WITH INCREASING CLOUDS AND POSSIBLY A FEW LIGHT SHOWERS FROM MID MORNING THROUGH MID AFTERNOON. CIGS AND VSBY WILL REMAIN VFR WITH THIS GIVEN THE DRY LOW LEVELS. FOR THE REST OF THE AREA JUST EXPECT A SHIFT IN WIND DIRECTION AND INCREASE IN SPEED WITH THE FRONTAL PASSAGE AND JUST A FEW SCATTERED CLOUDS. OUTLOOK... SUNDAY...VFR. SUNDAY NIGHT AND MONDAY...AREAS OF MVFR WITH OCCASIONAL SHOWERS AND GUSTY WINDS. TUESDAY AND WEDNESDAY...VFR/MVFR WITH A CHANCE OF SHOWERS. && .MARINE... RELATIVELY LIGHT WINDS WILL CONTINUE ON THE LOWER LAKES THROUGH TONIGHT AS A WEAK RIDGE OF HIGH PRESSURE BRIEFLY BUILDS ACROSS THE OHIO VALLEY. A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE AREA SATURDAY MORNING. NORTHWEST WINDS WILL INCREASE IN THE WAKE OF THE COLD FRONT AND PRODUCE CHOPPY WAVES IN THE AFTERNOON ESPECIALLY ON LAKE ONTARIO...BUT CONDITIONS ARE EXPECTED TO REMAIN JUST BELOW SMALL CRAFT ADVISORY CRITERIA. THE STRONGEST WINDS WILL BE FOUND ACROSS THE SAINT LAWRENCE VALLEY WHERE 20-25 KNOTS SUSTAINED ARE EXPECTED DURING THE AFTERNOON. WITH THIS IN MIND...WE HAVE ISSUED A SHORT LIVED SMALL CRAFT ADVISORY FOR SATURDAY AFTERNOON FOR THE SAINT LAWRENCE RIVER. LIGHTER WINDS WILL RETURN FOR SUNDAY AS HIGH PRESSURE BUILDS ACROSS QUEBEC. A FAIRLY STRONG AREA OF LOW PRESSURE WILL MOVE THROUGH THE CENTRAL LAKES LATER SUNDAY NIGHT AND MONDAY AND BRING AN INCREASE IN WINDS AND POTENTIAL SMALL CRAFT ADVISORY CONDITIONS TO THE LOWER LAKES. && .FIRE WEATHER... NEAR RED FLAG CONDITIONS ARE EXPECTED ON SATURDAY AFTERNOON. A COLD FRONT WILL MOVE ACROSS THE REGION LATE SATURDAY MORNING. BEHIND THE COLD FRONT WINDS WILL INCREASE OUT OF THE NORTHWEST WITH SUSTAINED WINDS OF 20-25 MPH AND GUSTS OF 30-35 MPH ESPECIALLY ACROSS THE NORTH COUNTRY AND THE HIGHER TERRAIN OF THE INTERIOR SOUTHERN TIER AND FINGER LAKES. RH WILL ALSO DROP DURING THE AFTERNOON FROM A COMBINATION OF DIURNAL WARMING AND DRY ADVECTION BEHIND THE COLD FRONT. THIS WILL DROP RH TO AROUND 25 PERCENT IN MANY AREAS AWAY FROM THE LAKESHORES DURING THE AFTERNOON. WIND AND RH WILL APPROACH RED FLAG CRITERIA...HOWEVER THE BULK OF THE AREA HAD A QUARTER INCH OR MORE OF RAIN LAST NIGHT. THE RECENT RAINFALL MAKES FINE FUELS WETTER...AND TAKES OUR REGION OUT OF RED FLAG CRITERIA. THE ONLY LOCATION WHICH RECEIVED LOWER RAIN AMOUNTS IS THE NORTH COUNTRY...HOWEVER SNOW ACROSS THE HIGHER TERRAIN OF THE TUG HILL AND WESTERN ADIRONDACKS HAS JUST MELTED IN THE PAST DAY OR TWO...SO FINE FUELS ACROSS MANY OF THESE AREAS ARE LIKELY STILL TOO WET TO JUSTIFY ANY FIRE WEATHER HEADLINES. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON TO 8 PM EDT SATURDAY FOR SLZ022- 024. && $$ SYNOPSIS...HITCHCOCK NEAR TERM...CHURCH/HITCHCOCK SHORT TERM...THOMAS LONG TERM...THOMAS AVIATION...CHURCH/HITCHCOCK MARINE...HITCHCOCK FIRE WEATHER...HITCHCOCK
AREA FORECAST DISCUSSION
NWS BUFFALO NY
759 PM EDT FRI APR 17 2015 .SYNOPSIS... HIGH PRESSURE WILL BRING CLEARING SKIES TONIGHT. A COLD FRONT WILL MOVE ACROSS THE REGION ON SATURDAY...HOWEVER THE FRONT IS MOISTURE STARVED SO MOST AREAS WILL REMAIN MOSTLY SUNNY AND BREEZY. A FEW SCATTERED LIGHT SHOWERS ARE POSSIBLE ACROSS THE NORTH COUNTRY WHERE A LITTLE MORE MOISTURE IS AVAILABLE. HIGH PRESSURE WILL BRING A RETURN TO DRY WEATHER FOR SUNDAY. LOW PRESSURE WILL MOVE THROUGH THE GREAT LAKES SUNDAY NIGHT AND MONDAY WITH OCCASIONAL SHOWERS AND GUSTY WINDS. UNSETTLED AND COOL WEATHER IS THEN EXPECTED MOST OF NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY/... DRIER AIR ADVECTING INTO THE REGION OUT OF SOUTHERN ONTARIO IS FINALLY ALLOWING THE STUBBORN LOW STRATUS TO ERODE IN MOST AREAS. MOIST AIR CROSSING THE COLD LAKES WILL CONTINUE TO PRODUCE SOME LOCAL LOW STRATUS AND FOG THROUGH EARLY EVENING EAST OF LAKES ERIE AND ONTARIO. VISIBLE SATELLITE SHOWS CLEARING FROM WEST TO EAST ACROSS EASTERN LAKE ERIE THIS EVENING...AND THUS SUSPECT DOWNTOWN BUFFALO WILL SEE A PERIOD OF CLEARING FOR SEVERAL HOURS THIS EVENING. HOWEVER...THE 00Z BUF SOUNDINGS SHOWS A NICELY ESTABLISHED MARINE LAYER WITH A SHARP INVERSION ABOVE 700 FEET AGL. THIS INVERSION SHOULD KEEP A TIGHT CAP ON THE MARINE MOISTURE OFF THE LAKES...AND AS SOUTHWESTERLY WINDS INCREASE AGAIN LATER TONIGHT...SHOULD SUPPORT ANOTHER ROUND OF FOG FOR THE BUFFALO AND WATERTOWN AREAS AFTER MIDNIGHT. NAM/SREF/GFS BUFKIT SOUNDINGS PICK UP ON THIS INVERSION NICELY...AND SHOW SUPPORT FOR FOG DEVELOPING OVER THE LAKES AFTER MIDNIGHT AND ADVECTING INLAND. BY TOMORROW MORNING...THE APPROACHING COLD FRONT WILL GIVE THE FORCING NEEDED TO FINALLY BREAK THIS UP THIS MARINE LAYER AND SCOUR OUT ANY FOG THAT REDEVELOPS OVERNIGHT. IN FACT...THE HRRR PICKS UP NICELY ON A PERIOD OF CLEARING FOR BUFFALO THIS EVENING...BEFORE ADVECTING FOG DOWN THE LAKE AND INTO THE BUFFALO/NIAGARA FALLS AREAS ON A SOUTHWESTERLY TO SOUTH-SOUTHWESTERLY FLOW. A WEAK BUBBLE OF HIGH PRESSURE WILL BUILD INTO THE OHIO VALLEY TONIGHT WITH A RIDGE EXTENDING INTO THE LOWER LAKES. SUBSIDENCE AND DRYING ASSOCIATED WITH THIS HIGH WILL FINISH THE CLEARING PROCESS TONIGHT AND SUPPORT CLEAR SKIES OVERNIGHT. EXPECT LOWS IN THE LOWER 40S IN MOST LOCATIONS WITH MID TO UPPER 30S IN THE COOLEST SOUTHERN TIER VALLEYS AND NORTH COUNTRY. ON SATURDAY A POTENT MID LEVEL SHORTWAVE AND ASSOCIATED WEAK SURFACE LOW WILL CROSS QUEBEC AND NEW ENGLAND. A TRAILING SURFACE COLD FRONT WILL CROSS OUR REGION DURING THE LATE MORNING. DESPITE THE STRONG ASCENT WITH THE SHORTWAVE...THE FRONT WILL BE MOISTURE STARVED WITH LITTLE EVEN IN THE WAY OF CLOUD COVER FOR THE BULK OF THE AREA. THE STRONGEST FORCING AND SOMEWHAT BETTER MOISTURE WILL CLIP THE NORTH COUNTRY WHERE A FEW SPRINKLES OR LIGHT SHOWERS ARE POSSIBLE FROM MID MORNING THROUGH MID AFTERNOON ALONG WITH MORE CLOUD COVER. THE REST OF THE AREA SHOULD REMAIN MOSTLY SUNNY. NORTHWEST WINDS WILL BECOME A LITTLE GUSTY BEHIND THE COLD FRONT SATURDAY AFTERNOON...WITH GUSTS IN THE 30-35 MPH RANGE ESPECIALLY ACROSS THE HIGHER TERRAIN OF THE INTERIOR SOUTHERN TIER...FINGER LAKES...AND NORTH COUNTRY. DESPITE THE COLD FRONTAL PASSAGE...DEEP MIXING AND SUNSHINE WILL BOOST HIGHS INTO THE MID 60S IN MOST AREAS WITH UPPER 50S TO LOWER 60S NORTH COUNTRY. GRADIENT ONSHORE FLOW WILL KEEP THE LAKE ERIE AND ONTARIO SHORES COOLER. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... SATURDAY NIGHT THROUGH MOST OF SUNDAY QUIET WEATHER CONDITIONS ARE EXPECTED ACROSS THE REGION AS HIGH PRESSURE ADVANCES ACROSS SOUTHERN QUEBEC. THROUGH THE COURSE OF SUNDAY MID AND HIGH LEVEL CLOUDS WILL BE INCREASING FROM WEST TO EAST ACROSS NEW YORK STATE...THESE CLOUDS ARE IN ADVANCE OF A WARM FRONT THAT WILL BE LIFTING NORTHWARD ACROSS THE OHIO VALLEY. THIS WARM FRONT WILL BE CONNECTED TO AN AREA OF LOW PRESSURE THAT WILL LIFT NORTHWARD FROM WESTERN KENTUCKY SUNDAY TO NORTHERN MICHIGAN MONDAY MORNING. GULF MOISTURE WILL INCREASE ACROSS THE EASTERN GREAT LAKES REGION LATE SUNDAY AFTERNOON AND SUNDAY NIGHT AS THE WARM FRONT FROM THE SOUTH REACHES WESTERN NEW YORK. STRONG LOW LEVEL CONVERGENCE FROM A 65 TO 70 KNOT LLJ CENTERED NEAR 850 TO 900 HPA WILL BRING LIFT ACROSS THE WARM FRONT...SUCH THAT WIDESPREAD RAIN FALL UPON THE REGION SUNDAY NIGHT. A QUARTER TO HALF INCH OF RAINFALL IS EXPECTED SUNDAY NIGHT AND INTO MONDAY MORNING FROM THIS SYSTEM. WINDS WILL ALSO BECOME GUSTY LATER SUNDAY NIGHT ALONG THE LAKE ERIE SHORE...WHERE A SE LLJ ALOFT BRINGS SURFACE GUSTS 30 TO 40 KNOTS ALONG THE SHORELINE. AS THE WARM FRONT AND ASSOCIATED RAIN LIFTS NORTHWARD OUT OF THE REGION MONDAY...THERE IS THE POTENTIAL FOR LIMITED SUNSHINE ALONG WITH A BRIEF WINDOW OF RAINFREE CONDITIONS. WITH THE LLJ STILL OVERHEAD...ANY SUNSHINE WILL INCREASE THE MIXING HEIGHTS SUCH THAT WE COULD TAP INTO THIS LLJ...WITH WIND GUSTS MONDAY ALSO 30 TO 35 KNOTS ACROSS WESTERN AND NORTH CENTRAL NEW YORK. LATER MONDAY AFTERNOON CLOUDS WILL THICKEN FROM WEST TO EAST...AND A DECREASE IN THE GUSTY WINDS IS EXPECTED. A COLD FRONT FROM THIS CENTRAL LAKES STORM SYSTEM WILL NEAR WESTERN NEW YORK LATE MONDAY AFTERNOON. ANOTHER ROUND OF RAIN SHOWERS IS EXPECTED MONDAY AFTERNOON AND MONDAY NIGHT ALONG AND AHEAD OF THE COLD FRONT. ANOTHER RAINFALL EVENT AVERAGING AROUND A QUARTER OF AN INCH IS EXPECTED. RAINFALL VALUES MAY RANGE GREATER WITH THE COLD FRONT PASSAGE THAN THE EARLIER WARM FRONT DUE TO THE CONVECTIVE NATURE OF THE RAIN SHOWERS. MID LEVEL LAPSE RATES ARE NOT PARTICULARLY STRONG AND WITH THE OVERNIGHT PASSAGE OF THE COLD FRONT FOR NOW WILL NOT INCLUDE ANY MENTION OF THUNDER WITH THIS FORECAST PACKAGE...EVEN THROUGH THERE IS SOME SKINNY MID LEVEL CAPE. THE WARMEST DAY THIS PERIOD WILL BE MONDAY WHEN BEFORE THE COLD FRONT 850 HPA TEMPERATURES WILL SURGE TO +7 TO +10C. THESE READINGS WILL SUPPORT HIGHS IN THE 60S...WITH 70S POSSIBLE ACROSS LOWER ELEVATIONS ON A SOUTHEAST WIND. && .LONG TERM /TUESDAY THROUGH FRIDAY/... CLASSIC SPRING-TIME PATTERN THIS TIME PERIOD AS A DEVELOPING NEGATIVE NAO ALLOWS FOR A UPPER LEVEL CUT OFF LOW TO STALL OVER EASTERN CANADA AND THE NORTHEAST UNITED STATES. UNDER THIS LOW PRESSURE EXPECT CLOUDY DAYS WITH SCATTERED RAIN SHOWERS. RAIN SHOWER ACTIVITY WILL BE MOST PRONOUNCED IN THE AFTERNOON HOURS WITH DAYTIME HEATING...WITH FEW SHOWERS TO BE FOUND BY NIGHT. THERE MAY EVEN BE SOME WET SNOW MIXING IN AT NIGHT ACROSS THE REGION. DAYTIME AIR TEMPERATURES WILL AVERAGE 5 TO 10 DEGREES BELOW NORMAL. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THIS EVENING WITH HIGH PRESSURE BUILDING. SOME FOG WILL PERSIST NEAR THE LAKE SHORES EARLY THIS EVENING...BUT SHOULD BREAK UP WITH SOME DRIER AIR MOVING IN. THEN AFTER MIDNIGHT...MOISTURE TRAPPED UNDER A SHARP INVERSION WILL BE ENHANCED BY LAKES ERIE AND ONTARIO. SOUTHWEST TO SOUTH-SOUTHWESTERLY WINDS COULD BRING SOME AREAS OF FOG INTO THE KBUF/KIAG/KART TERMINALS...HOWEVER FORECAST CONFIDENCE IN THE INLAND EXTENT OF THIS FOG TO THE TERMINALS REMAINS LOW. ON SATURDAY A MOISTURE STARVED SHARP MID LEVEL DISTURBANCE AND COLD FRONT WILL CROSS THE REGION. THE STRONGEST ASCENT WILL CROSS THE NORTH COUNTRY WITH INCREASING CLOUDS AND POSSIBLY A FEW LIGHT SHOWERS FROM MID MORNING THROUGH MID AFTERNOON. CIGS AND VSBY WILL REMAIN VFR WITH THIS GIVEN THE DRY LOW LEVELS. FOR THE REST OF THE AREA JUST EXPECT A SHIFT IN WIND DIRECTION AND INCREASE IN SPEED WITH THE FRONTAL PASSAGE AND JUST A FEW SCATTERED CLOUDS. OUTLOOK... SUNDAY...VFR. SUNDAY NIGHT AND MONDAY...AREAS OF MVFR WITH OCCASIONAL SHOWERS AND GUSTY WINDS. TUESDAY AND WEDNESDAY...VFR/MVFR WITH A CHANCE OF SHOWERS. && .MARINE... RELATIVELY LIGHT WINDS WILL CONTINUE ON THE LOWER LAKES THROUGH TONIGHT AS A WEAK RIDGE OF HIGH PRESSURE BRIEFLY BUILDS ACROSS THE OHIO VALLEY. A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE AREA SATURDAY MORNING. NORTHWEST WINDS WILL INCREASE IN THE WAKE OF THE COLD FRONT AND PRODUCE CHOPPY WAVES IN THE AFTERNOON ESPECIALLY ON LAKE ONTARIO...BUT CONDITIONS ARE EXPECTED TO REMAIN JUST BELOW SMALL CRAFT ADVISORY CRITERIA. THE STRONGEST WINDS WILL BE FOUND ACROSS THE SAINT LAWRENCE VALLEY WHERE 20-25 KNOTS SUSTAINED ARE EXPECTED DURING THE AFTERNOON. WITH THIS IN MIND...WE HAVE ISSUED A SHORT LIVED SMALL CRAFT ADVISORY FOR SATURDAY AFTERNOON FOR THE SAINT LAWRENCE RIVER. LIGHTER WINDS WILL RETURN FOR SUNDAY AS HIGH PRESSURE BUILDS ACROSS QUEBEC. A FAIRLY STRONG AREA OF LOW PRESSURE WILL MOVE THROUGH THE CENTRAL LAKES LATER SUNDAY NIGHT AND MONDAY AND BRING AN INCREASE IN WINDS AND POTENTIAL SMALL CRAFT ADVISORY CONDITIONS TO THE LOWER LAKES. && .FIRE WEATHER... NEAR RED FLAG CONDITIONS ARE EXPECTED ON SATURDAY AFTERNOON. A COLD FRONT WILL MOVE ACROSS THE REGION LATE SATURDAY MORNING. BEHIND THE COLD FRONT WINDS WILL INCREASE OUT OF THE NORTHWEST WITH SUSTAINED WINDS OF 20-25 MPH AND GUSTS OF 30-35 MPH ESPECIALLY ACROSS THE NORTH COUNTRY AND THE HIGHER TERRAIN OF THE INTERIOR SOUTHERN TIER AND FINGER LAKES. RH WILL ALSO DROP DURING THE AFTERNOON FROM A COMBINATION OF DIURNAL WARMING AND DRY ADVECTION BEHIND THE COLD FRONT. THIS WILL DROP RH TO AROUND 25 PERCENT IN MANY AREAS AWAY FROM THE LAKESHORES DURING THE AFTERNOON. WIND AND RH WILL APPROACH RED FLAG CRITERIA...HOWEVER THE BULK OF THE AREA HAD A QUARTER INCH OR MORE OF RAIN LAST NIGHT. THE RECENT RAINFALL MAKES FINE FUELS WETTER...AND TAKES OUR REGION OUT OF RED FLAG CRITERIA. THE ONLY LOCATION WHICH RECEIVED LOWER RAIN AMOUNTS IS THE NORTH COUNTRY...HOWEVER SNOW ACROSS THE HIGHER TERRAIN OF THE TUG HILL AND WESTERN ADIRONDACKS HAS JUST MELTED IN THE PAST DAY OR TWO...SO FINE FUELS ACROSS MANY OF THESE AREAS ARE LIKELY STILL TOO WET TO JUSTIFY ANY FIRE WEATHER HEADLINES. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON TO 8 PM EDT SATURDAY FOR SLZ022- 024. && $$ SYNOPSIS...HITCHCOCK NEAR TERM...CHURCH/HITCHCOCK SHORT TERM...THOMAS LONG TERM...THOMAS AVIATION...CHURCH/HITCHCOCK MARINE...HITCHCOCK FIRE WEATHER...HITCHCOCK
AREA FORECAST DISCUSSION
NWS RALEIGH NC
245 PM EDT THU APR 16 2015 .SYNOPSIS...CHILLY HIGH PRESSURE WILL EXTEND INTO THE CAROLINAS AND VIRGINIA FROM THE NORTHEAST THROUGH TONIGHT. A WEAK AREA OF LOW PRESSURE WILL DEVELOP OFF THE SOUTHEAST U.S. COAST TODAY AND DRIFT NORTHEAST AND AWAY FROM THE REGION ON FRIDAY. WEAK HIGH PRESSURE WILL EXTEND INTO THE AREA LATE FRIDAY INTO SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1100 AM THURSDAY... VERY WELL DEFINED WEDGE FRONT ASSOCIATED WITH A HYBRID COLD AIR DAMMING EVENT SHOWING UP NICELY IN OBSERVATIONS. TO THE SOUTHEAST...A COASTAL LOW IS DEVELOPING OFF THE COAST OF SC AND FURTHER ENHANCING THE WEDGE BOUNDARY. THIS WILL MAKE TEMPERATURE FORECASTS VERY TRICKY TODAY AS A VERY STRONG GRADIENT WILL BE PRESENT FROM WEST TO EAST WITH VERY COOL HIGHS IN THE WEST AND POTENTIALLY QUITE A BIT WARMER HIGHS IN THE EAST. FOR NOW HAVE MID 50S IN THE WEST AND UPPER 60S IN THE EAST BUT BY LATE IN THE AFTERNOON THIS COULD VERY WELL PAN OUT TO BE LOWER 50S IN THE WEST AND LOWER TO MID 70S IN THE EASTERN TIER OF COUNTIES. PRECIPITATION CONTINUES ACROSS THE CENTRAL PIEDMONT AND THE NORTHEASTERN COUNTIES AIDED BY ISENTROPIC LIFT AND SOME UPPER LEVEL DIVERGENCE AS WE SIT UNDER THE LEFT EXIT REGION OF A 250 MB JET. PRECIPITATION SHOULD BEGIN TO TREND DOWNWARD HOWEVER AS ISENTROPIC LIFT WEAKENS AND SOME VERY DRY MID-LEVEL AIR TO THE NORTHEAST TRIES TO WORK SOUTHWESTWARD INTO THE CWA. THIS IS VERY EVIDENT ON THE SOUNDINGS WHERE THE KMHX SOUNDING HAS A 5 DEGREE DEWPOINT DEPRESSION AT 850 MB AND THE KWAL SOUNDING HAS A 33 DEGREE DEWPOINT DEPRESSION. AS PRECIPITATION MOVES NORTHEAST...COMPOSITE RADAR SHOWS EVAPORATION OF THE PRECIPITATION...MOST LIKELY CAUSED BY THE MID LEVEL DRY AIR. AS FAR AS CONVECTIVE ALLOWING MODELS ARE CONCERNED...ONLY ONE REALLY HAS A HANDLE OF THE CURRENT MODE OF PRECIP AND THAT IS THE HRRR WHICH DEPICTS THE CURRENT PATTERN VERY WELL. GOING INTO THIS AFTERNOON THE RAIN OVER THE CENTRAL PART OF THE CWA PUSHES NORTHEAST AND CHANCES ELSEWHERE DIMINISH THROUGH THE AFTERNOON TO JUST A FEW PATCHES OF DRIZZLE OR LIGHT RAIN BY THIS EVENING. CLOUDS SHOULD REMAIN OVERNIGHT...THUS MODERATING LOWS...MAINLY LOW TO MIDDLE 50S NW TO SE. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 245 PM THURSDAY... FRIDAY SHOULD SEE THE BEGINNING OF A SLOW IMPROVEMENT IN SKY CONDITION AND TEMPS. DEVELOPING (THOUGH WEAK) NW FLOW IN THE MID- UPPER LEVELS WILL BEGIN TO SCOUR THE CAD AIR MASS FROM ALOFT. STILL...RESIDUAL LOW LEVEL MOISTURE WILL REMAIN HIGH ENOUGH TO PRODUCE EXTENSIVE CLOUDINESS IN THE MORNING WITH SOME PARTIAL BREAKS DEVELOPING IN THE AFTERNOON. THIS HEATING ALONG WITH THE PASSAGE OF A WEAK MID LEVEL TROUGH MAY PROVIDE ENOUGH LIFT TO GENERATE AN ISOLATED SHOWER OR THUNDERSTORM ACROSS CENTRAL NC. TEMPS WILL BEGIN TO RECOVER FRIDAY THOUGH IF CLOUDS STICK AROUND A LOT LONGER THAN EXPECTED...MAX TEMPS MAY END UP BEING 3-5 DEGREES COOLER THAN CURRENTLY FORECAST...ESPECIALLY ACROSS THE NORTHERN PIEDMONT. MAX TEMPS FRIDAY LOW-MID 70S. FRIDAY NIGHT... PARTIAL CLEARING MAY LEAD TO THE DEVELOPMENT OF FOGGY CONDITIONS AFTER MIDNIGHT. MIN TEMPS 55- 60. -WSS SAT/SAT NIGHT: EXPECT DRY WEATHER AND PLENTY OF SUNSHINE SAT. A WEAK BACKDOOR FRONT WILL DROP THROUGH NC IN THE MORNING... OTHERWISE WE`LL HAVE SURFACE HIGH PRESSURE OVER THE REGION AND A DRY/SUBSIDING COLUMN BENEATH MID LEVEL RIDGING. WE MAY GET WARM AND MOIST ENOUGH IN THE SOUTHEAST FOR POTENTIAL INLAND-MOVING SEA BREEZE CONVECTION... SO WILL RETAIN THE EXISTING ISOLATED MENTION FOR THE AFTERNOON. WITH THICKNESSES LIKELY NEARING 20 M ABOVE NORMAL AND GOOD MIXING EXPECTED... HIGHS IN THE UPPER 70S TO LOWER 80S APPEAR ATTAINABLE. A STRONG VORTICITY MAX AND WAVE CROSSING NRN NEW ENGLAND SAT WILL HELP PROPEL A MORE PRONOUNCED BACKDOOR FRONT SOUTHWARD TO NEAR THE VA/NC BORDER LATE SAT NIGHT... PUSHED BY COOL DENSE HIGH PRESSURE CENTERED OVER WRN QUEBEC. MODELS DIFFER REGARDING HOW FAR (IF AT ALL) THE FRONT GETS INTO NE NC... WITH THE GFS A BIT FARTHER SSW THAN THE NAM/ECMWF. GIVEN THE STRENGTH OF THE PARENT HIGH AND INTENSITY OF THE NEW ENGLAND WAVE... THINK WE`LL SEE ENOUGH PENETRATION INTO OUR CWA FOR BRIEFLY LOWER DEWPOINTS AND TEMPS INTO THE NE CWA. EXPECT LOWS IN THE UPPER 50S TO LOWER 60S EXCEPT MID 50S FAR NE. THE STRONG LOW CLOSING OFF OVER SASK/MANITOBA AND ATTENDING TROUGH THROUGH THE DAKOTAS ULTIMATELY PICK UP THE SRN STREAM LOW OVER THE CENTRAL PLAINS... CULMINATING IN DEEP MID LEVEL TROUGHING THROUGH CENTRAL NOAM BY DAWN SUNDAY. WHILE WE`RE LIKELY TO SEE INCREASING CLOUDS FROM THE SW SAT NIGHT WITH ENCROACHING DPVA ALOFT AND IMPROVING MOIST INFLOW IN THE LOWER LEVELS... ANY LIFT IS TOO WEAK AND THE COLUMN STILL TOO DRY OVERALL TO SUPPORT ANY PRECIP THROUGH DAWN SUNDAY. -GIH && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 245 PM THURSDAY... SUN-MON NIGHT: A WET AND POTENTIALLY STORMY PERIOD. MID LEVEL FLOW OVER OUR REGION BECOMES INCREASINGLY CYCLONIC AS THE SLIGHTLY POSITIVELY TILTED BUT SLOWLY DAMPENING LARGE SCALE TROUGH APPROACHES FROM THE WSW. AT THE SURFACE... THE ASSOCIATED FRONTAL SYSTEM WILL OCCLUDE OVER THE UPPER MIDWEST AND GREAT LAKES SUN/SUN NIGHT... WITH THE BACKDOOR FRONT AROUND THE NC/VA BORDER SLOWLY RETREATING BACK TO THE NNE AS A WARM FRONT... WHILE THE PRIMARY COLD FRONT EXTENDS FROM A TRIPLE POINT LOW OVER LOWER MICH DOWN THROUGH THE MID/LOWER MISS VALLEY. MECHANISMS TO FORCE ASCENT SUCH AS MID LEVEL DPVA... UPPER DIVERGENCE... AND LOWER LEVEL (850-925 MB) MASS CONVERGENCE WILL BE STRENGTHENING (ESPECIALLY OVER WRN NC/SW VA) LATE SUN... PERSISTING THROUGH SUN EVENING AND INTO THE NIGHT... AND MOISTURE WILL BE ABUNDANT WITH AN INFLUX OF PW VALUES OVER 1.5"... OR WELL OVER 200% OF NORMAL. GIVEN THIS PLENTIFUL WATER CONTENT AND GOOD LIFT... TRAINING BANDS OF MODERATE RAIN COULD BRING LOCALIZED FLOODING PROBLEMS. MODELS CONTINUE TO SLOW DOWN THE ARRIVAL OF THE MID LEVEL TROUGH AND ITS ACCOMPANYING PRECIP... 6-9 HRS SLOWER THAN YESTERDAY MORNING`S RUNS... AND WILL CONTINUE TO REFLECT THIS IN THE FORECAST. WILL RAMP UP POPS TO LIKELY WEST/SMALL CHANCE EAST SUN MORNING... THEN GO TO CATEGORICAL WEST/GOOD CHANCE EAST SUN AFTERNOON... BEFORE GOING CATEGORICAL AREAWIDE SUN EVENING/NIGHT. WHILE THE LARGE SCALE MODELS DON`T DEPICT MUCH INSTABILITY AT ALL SUNDAY WITH PRIMARILY MOIST ADIABATIC FORECAST PROFILES... I DO HAVE SOME CONCERN ABOUT POCKETS OF CONVECTION AND AN ISOLATED THREAT OF A QUICK WEAK SPIN-UP IN OUR FAR NORTHWEST LATE SUNDAY INTO SUNDAY NIGHT... ESPECIALLY NEAR A WEAK ALONG-FRONT LOW THAT THE GFS/ECMWF DEVELOP OVER SOUTH CENTRAL VA. UPPER DIVERGENCE REACHES A HEFTY MAXIMUM OVER THE SRN APPALACHIANS SUN EVENING... WITH A 40-50 KT 850 MB JETLET FROM THE SSE... AND THE RETREATING BACKDOOR FRONTAL ZONE AND AFOREMENTIONED LOW COULD PROVIDE A SOURCE FOR ENHANCED LOW LEVEL VORTICITY WITH FORECAST SOUNDINGS SHOWING A STRONGLY CURVED HODOGRAPH. WILL CONTINUE TO MONITOR. TOTAL RAINFALL IS LIKELY TO REACH AT LEAST ONE INCH IN MOST SPOTS THROUGH SUN NIGHT... AND WITH A DEEP WARM LAYER (LCL TO 0C) NEAR 3.5 KM FAVORING WARM RAIN PROCESSES... LOCALLY HIGHER TOTALS ARE POSSIBLE. WILL TAPER POPS DOWN MON MORNING WEST TO EAST AS THE MID LEVEL TROUGH AXIS AND CONVEYOR BELT OF PEAK MOISTURE PUSHES TO OUR NORTHEAST... PLACING US FULLY IN THE WARM SECTOR WITH A PUNCH OF MID LEVEL DRY AIR ARRIVING FROM THE SW. ANY HEATING AT ALL WILL PUSH UP MUCAPE TO 1500-2000 J/KG (AS THE GFS SUGGESTS) MON AFTERNOON WITH 25-30 KT WSW 850 MB WINDS AND BULK SHEAR NEAR 30-35 KTS. THE SLOWLY LOWERING DYNAMIC FORCING FOR ASCENT MAY LIMIT THE THREAT OF SEVERE STORMS... BUT STILL EXPECT AT LEAST A FEW STRONG CELLS... ESPECIALLY IF WE DO INDEED GET SOME HEATING AHEAD OF THE COLD FRONT. AFTER A DOWNWARD TREND TO RAIN WEST TO EAST IN THE MORNING... WILL REBOUND WITH SCATTERED SHOWERS AND STORMS MON AFTERNOON INTO EARLY EVENING. A FEW OF THESE COULD PRODUCE STRONG GUSTY STRAIGHT LINE WINDS GIVEN INDICATIONS OF A STRAIGHT LINE HODOGRAPH. HIGHS FROM AROUND 70 NW TO THE MID 70S SE. LOWS AROUND 60 TO THE MID 60S WITH THE FRONT LIKELY NOT COMING THROUGH UNTIL LATE. TUE-THU: FAIRLY QUIET AND DRY WITH SURFACE HIGH PRESSURE BUILDING IN FROM THE WEST. LARGE/DEEP MID LEVEL LOW PRESSURE CENTERED OVER AND NORTH OF THE NRN GREAT LAKES WILL COVER MUCH OF CENTRAL AND EASTERN NOAM... BRINGING SEASONABLY COOL TEMPS AS IT SITS AND SPINS THROUGH MID WEEK. WE COULD SEE A QUICK SHOT OF LIGHT PRECIP WITH A FRONT APPROACHING FROM THE NW WED NIGHT OR THU... HOWEVER OUR MOISTURE SOURCES WILL REMAIN UNTAPPED AND LIFT APPEARS WEAK... SO THIS SHOULD AMOUNT TO ONLY LIGHT PRECIP AT MOST... AND WILL KEEP POPS WED NIGHT/THU BELOW CLIMATOLOGY. TEMPS SHOULD HOLD NEAR OR JUST BELOW NORMAL THROUGH THE PERIOD. -GIH && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AS OF 205 PM THURSDAY... 24 HOUR TAF PERIOD: VARIABLE CONDITIONS ACROSS THE CWA RIGHT NOW AS PREDOMINANTLY IFR CEILINGS AND MVFR VISIBILITIES HAVE OVERSPREAD THE SOUTHWESTERN COUNTIES...MVFR CONDITIONS OVER THE NW PIEDMONT ARE SETTLING BACK IN AND VFR TO THE EAST. WHILE CONDITIONS WILL VARY THIS AFTERNOON BASED ON CLOUD COVER AND PLACEMENT OF PRECIPITATION THERE WILL BE AN OVERALL TREND OF IMPROVING IN THE EAST THIS AFTERNOON AND HOLDING STEADY IN THE WEST WHERE THE CAD WEDGE HAS MORE INFLUENCE. OVERNIGHT TONIGHT EXPECT CEILINGS TO GO DOWN TO AT LEAST IFR LEVELS IN MOST LOCATIONS. THIS WILL HAPPEN EARLIER IN THE WEST AND LATER IN EAST. CONVERSELY...AFTER SUNRISE FRIDAY EXPECT EASTERN SITES TO RECOVER TO VFR FASTER THAN WESTERN SITES WHICH COULD HOLD MVFR THROUGH THE END OF THE TAF PERIOD. MOSTLY NNE WINDS AT THIS TIME AT 5-10 KTS BUT AS COASTAL LOW DEVELOPS OFF OF NC...BIGGER EASTWARD COMPONENT COMING IN...CURRENTLY NOTED AT KRWI. BIGGEST THREAT TO CEILINGS OVERNIGHT WILL BE LOW CEILINGS WITH VISIBILITIES SECONDARY. RAIN SHOULD TAPER OFF AFTER SUNSET. ONCE THAT HAPPENS SHOULD BE DRY THROUGH THE END OF THE TAF PERIOD. LONG TERM: RETURN TO MAINLY VFR CONDITIONS FRIDAY AFTERNOON THROUGH SATURDAY. CHANCE FOR ADVERSE CONDITIONS WITH A COLD FRONT SUNDAY INTO MONDAY AND THEN IMPROVING CONDITIONS FOR MIDWEEK NEXT WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...ELLIS SHORT TERM...WSS/HARTFIELD LONG TERM...HARTFIELD AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
207 PM EDT THU APR 16 2015 .SYNOPSIS...CHILLY HIGH PRESSURE WILL EXTEND INTO THE CAROLINAS AND VIRGINIA FROM THE NORTHEAST THROUGH TONIGHT. A WEAK AREA OF LOW PRESSURE WILL DEVELOP OFF THE SOUTHEAST U.S. COAST TODAY AND DRIFT NORTHEAST AND AWAY FROM THE REGION ON FRIDAY. WEAK HIGH PRESSURE WILL EXTEND INTO THE AREA LATE FRIDAY INTO SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1100 AM THURSDAY... VERY WELL DEFINED WEDGE FRONT ASSOCIATED WITH A HYBRID COLD AIR DAMMING EVENT SHOWING UP NICELY IN OBSERVATIONS. TO THE SOUTHEAST...A COASTAL LOW IS DEVELOPING OFF THE COAST OF SC AND FURTHER ENHANCING THE WEDGE BOUNDARY. THIS WILL MAKE TEMPERATURE FORECASTS VERY TRICKY TODAY AS A VERY STRONG GRADIENT WILL BE PRESENT FROM WEST TO EAST WITH VERY COOL HIGHS IN THE WEST AND POTENTIALLY QUITE A BIT WARMER HIGHS IN THE EAST. FOR NOW HAVE MID 50S IN THE WEST AND UPPER 60S IN THE EAST BUT BY LATE IN THE AFTERNOON THIS COULD VERY WELL PAN OUT TO BE LOWER 50S IN THE WEST AND LOWER TO MID 70S IN THE EASTERN TIER OF COUNTIES. PRECIPITATION CONTINUES ACROSS THE CENTRAL PIEDMONT AND THE NORTHEASTERN COUNTIES AIDED BY ISENTROPIC LIFT AND SOME UPPER LEVEL DIVERGENCE AS WE SIT UNDER THE LEFT EXIT REGION OF A 250 MB JET. PRECIPITATION SHOULD BEGIN TO TREND DOWNWARD HOWEVER AS ISENTROPIC LIFT WEAKENS AND SOME VERY DRY MID-LEVEL AIR TO THE NORTHEAST TRIES TO WORK SOUTHWESTWARD INTO THE CWA. THIS IS VERY EVIDENT ON THE SOUNDINGS WHERE THE KMHX SOUNDING HAS A 5 DEGREE DEWPOINT DEPRESSION AT 850 MB AND THE KWAL SOUNDING HAS A 33 DEGREE DEWPOINT DEPRESSION. AS PRECIPITATION MOVES NORTHEAST...COMPOSITE RADAR SHOWS EVAPORATION OF THE PRECIPITATION...MOST LIKELY CAUSED BY THE MID LEVEL DRY AIR. AS FAR AS CONVECTIVE ALLOWING MODELS ARE CONCERNED...ONLY ONE REALLY HAS A HANDLE OF THE CURRENT MODE OF PRECIP AND THAT IS THE HRRR WHICH DEPICTS THE CURRENT PATTERN VERY WELL. GOING INTO THIS AFTERNOON THE RAIN OVER THE CENTRAL PART OF THE CWA PUSHES NORTHEAST AND CHANCES ELSEWHERE DIMINISH THROUGH THE AFTERNOON TO JUST A FEW PATCHES OF DRIZZLE OR LIGHT RAIN BY THIS EVENING. CLOUDS SHOULD REMAIN OVERNIGHT...THUS MODERATING LOWS...MAINLY LOW TO MIDDLE 50S NW TO SE. && .SHORT TERM /FRIDAY AND FRIDAY NIGHT/... AS OF 317 AM THURSDAY... FRIDAY SHOULD SEE THE BEGINNING OF A SLOW IMPROVEMENT IN SKY CONDITION AND TEMPS. DEVELOPING (THOUGH WEAK) NW FLOW IN THE MID- UPPER LEVELS WILL BEGIN TO SCOUR THE CAD AIR MASS FROM ALOFT. STILL...RESIDUAL LOW LEVEL MOISTURE WILL REMAIN HIGH ENOUGH TO PRODUCE EXTENSIVE CLOUDINESS IN THE MORNING WITH SOME PARTIAL BREAKS DEVELOPING IN THE AFTERNOON. THIS HEATING ALONG WITH THE PASSAGE OF A WEAK MID LEVEL TROUGH MAY PROVIDE ENOUGH LIFT TO GENERATE AN ISOLATED SHOWER OR THUNDERSTORM ACROSS CENTRAL NC. TEMPS WILL BEGIN TO RECOVER FRIDAY THOUGH IF CLOUDS STICK AROUND A LOT LONGER THAN EXPECTED...MAX TEMPS MAY END UP BEING 3-5 DEGREES COOLER THAN CURRENTLY FORECAST...ESPECIALLY ACROSS THE NORTHERN PIEDMONT. MAX TEMPS FRIDAY LOW-MID 70S. FRIDAY NIGHT..PARTIAL CLEARING MAY LEAD TO THE DEVELOPMENT OF FOGGY CONDITIONS AFTER MIDNIGHT. MIN TEMPS 55-60. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 320 AM THURSDAY... SATURDAY AND SATURDAY NIGHT: MID LEVEL S/W RIDGING WILL LARGELY KEEP CENTRAL NC DRY ON SATURDAY AND SATURDAY NIGHT. HOWEVER... WITH AND EASTERLY TO SOUTHEASTERLY SURFACE FLOW DEVELOPING LATE SATURDAY ALONG WITH DAYTIME HEATING CANT COMPLETELY RULE OUT SOME AFTERNOON SHOWERS AND STORMS ACROSS FAR EASTERN PORTIONS OF THE AREA WHERE LOW LEVEL CONVERGENCE MAY BE ENHANCED SOME ALONG PERHAPS A SEABREEZE. THUS... WILL GO WITH A SLIGHT CHANCE FOR SHOWERS AND STORMS ACROSS OUR FAR EASTERN COUNTIES FOR SATURDAY AFTERNOON. WITH SKIES NOW EXPECTED TO BE AT LEAST PARTLY SUNNY AT TIMES WILL RAISE HIGH TEMPS A DEGREE OR TWO INTO THE UPPER 70S NW TO LOWER 80S SE. THE LATEST GFS/ECMWF/NAM NOW SHOW THE ONSET OF PRECIP DELAYED A GOOD 6 TO 12 HOURS FROM PREVIOUS FORECASTS. THUS... WILL NOT INTRODUCE POPS UNTIL CLOSE TO DAYBREAK... FIRST IN THE WEST THEN SPREADING EAST THROUGH THE DAY ON SUNDAY. WITH INCREASING SOUTHERLY LOW LEVEL FLOW AND CLOUD COVER ON SATURDAY NIGHT/EARLY SUNDAY MORNING EXPECT LOW TEMPS WILL ABOVE NORMAL... GENERALLY RANGING FROM THE MID 50S IN THE FAR NE (WHERE WE MAY SEE SOME CLEARING BRIEFLY WITH THE LOSS OF HEATING AND PRIOR TO THE INCREASING OF MID AND HIGH LEVEL CLOUDS COVER) TO GENERALLY NEAR 60 ELSEWHERE. SUNDAY THROUGH MONDAY NIGHT: GOOD MOISTURE TRANSPORT IS EXPECTED ON SUNDAY INTO SUNDAY NIGHT AS CLOSED LOW INVOF THE FOUR CORNERS REGION (CURRENTLY) SHIFT EASTWARD AND OPENS WHILE COMBINING WITH A NORTHERN STREAM TROUGH TO AMPLIFY THE MID/UPPER LEVEL FLOW ACROSS THE CENTRAL AND EASTERN PART OF THE COUNTRY LATE WEEKEND INTO EARLY NEXT WEEK. THIS WILL HELP TO DRIVE A LEAD DEEP MOIST AXIS THROUGH CENTRAL NC LATE SUNDAY THROUGH EARLY MONDAY MORNING. WITH STRONG SOUTHERLY LOW LEVEL FLOW WITH THIS SYSTEM AND EXCELLENT MOISTURE TRANSPORT WE SHOULD SEE A LARGE BAND OF SHOWER/ISOLATED STORMS AND HEAVY RAIN MOVE THROUGH CENTRAL NC LATE SUNDAY INTO SUNDAY NIGHT... WITH A MAIN THREAT OF HEAVY RAIN. ALTHOUGH GIVEN THE STRONG LOW LEVEL WIND FIELDS CAN COMPLETELY RULE OUT AT LEAST A STRONG WIND GUST OR TWO. BUT GIVEN THE RATHER WEAK INSTABILITY AND POOR DIURNAL TIMING FOR THE MOST PART ANY SEVERE THREAT SHOULD REMAIN LOW. HIGHS SHOULD BE COOLER SUNDAY WITH THE INCREASE IN CLOUDS AND EVENTUALLY PRECIP LATE IN THE DAY...EXPECT HIGHS TO BE IN THE MID TO UPPER 60S NW (WHERE WE COULD SEE A BRIEF CAD AIRMASS DEVELOP) TO THE MID 70S SE/E (MAYBE EVEN A FEW UPPER 70S SE). LOWS MONDAY MORNING SHOULD BE WARM FOR THIS TIME OF YEAR... EXPECT LOWS IN THE LOWER TO MID 60S. THE MAIN SURFACE COLD FRONT SHOULD MOVE THROUGH THE REGION LATE MONDAY INTO MONDAY EVENING. WHILE THE STRONGER MID AND LOW LEVEL FLOW WILL HAVE PUSHED TO THE EAST... WE SHOULD SEE INSTABILITY INCREASE AS SOME DRIER MID LEVEL AIR WORKS INTO THE AREA FROM THE SOUTHWEST ON MONDAY MORNING/AFTERNOON. THIS SHOULD HELP TO YIELD AT LEAST SOME DESTABILIZATION AHEAD OF THE FRONT ON MONDAY RESULTING IN ISOLATED TO SCATTERED SHOWER AND STORMS MONDAY AFTERNOON/EVENING IN ADVANCE OF THE FRONT... WITH POSSIBLY A FEW STRONG TO MAYBE SEVERE STORMS (AS DEEP LAYER SHEAR WILL STILL BE AROUND 25 TO 35 KTS). BEST CHANCE OF ANY SVR AT THIS TIME (KEEP IN MIND WE ARE STILL A WAYS OUT IN TIME) WOULD BE ACROSS EASTERN PORTIONS OF THE AREA. HIGHS MONDAY ARE EXPECTED TO BE IN THE 70S TO LOWER 80S EAST/SOUTHEAST. LOWS TUESDAY MORNING RANGING FROM THE MID 50S NW TO AROUND 60 SE. TUESDAY THROUGH WEDNESDAY: DRIER WEATHER IS EXPECTED BEHIND THE FRONT ON TUESDAY AND WEDNESDAY... WITH A MUCH DRIER AIRMASS ADVECTING INTO THE REGION. HIGH TEMPS SHOULD BE NEAR NORMAL GENERALLY IN THE 70S... WITH LOWS IN THE 40S AND 50S. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AS OF 205 PM THURSDAY... 24 HOUR TAF PERIOD: VARIABLE CONDITIONS ACROSS THE CWA RIGHT NOW AS PREDOMINANTLY IFR CEILINGS AND MVFR VISIBILITIES HAVE OVERSPREAD THE SOUTHWESTERN COUNTIES...MVFR CONDITIONS OVER THE NW PIEDMONT ARE SETTLING BACK IN AND VFR TO THE EAST. WHILE CONDITIONS WILL VARY THIS AFTERNOON BASED ON CLOUD COVER AND PLACEMENT OF PRECIPITATION THERE WILL BE AN OVERALL TREND OF IMPROVING IN THE EAST THIS AFTERNOON AND HOLDING STEADY IN THE WEST WHERE THE CAD WEDGE HAS MORE INFLUENCE. OVERNIGHT TONIGHT EXPECT CEILINGS TO GO DOWN TO AT LEAST IFR LEVELS IN MOST LOCATIONS. THIS WILL HAPPEN EARLIER IN THE WEST AND LATER IN EAST. CONVERSELY...AFTER SUNRISE FRIDAY EXPECT EASTERN SITES TO RECOVER TO VFR FASTER THAN WESTERN SITES WHICH COULD HOLD MVFR THROUGH THE END OF THE TAF PERIOD. MOSTLY NNE WINDS AT THIS TIME AT 5-10 KTS BUT AS COASTAL LOW DEVELOPS OFF OF NC...BIGGER EASTWARD COMPONENT COMING IN...CURRENTLY NOTED AT KRWI. BIGGEST THREAT TO CEILINGS OVERNIGHT WILL BE LOW CEILINGS WITH VISIBILITIES SECONDARY. RAIN SHOULD TAPER OFF AFTER SUNSET. ONCE THAT HAPPENS SHOULD BE DRY THROUGH THE END OF THE TAF PERIOD. LONG TERM: RETURN TO MAINLY VFR CONDITIONS FRIDAY AFTERNOON THROUGH SATURDAY. CHANCE FOR ADVERSE CONDITIONS WITH A COLD FRONT SUNDAY INTO MONDAY AND THEN IMPROVING CONDITIONS FOR MIDWEEK NEXT WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...ELLIS SHORT TERM...WSS LONG TERM...BSD AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1104 AM EDT THU APR 16 2015 .SYNOPSIS...CHILLY HIGH PRESSURE WILL EXTEND INTO THE CAROLINAS AND VIRGINIA FROM THE NORTHEAST THROUGH TONIGHT. A WEAK AREA OF LOW PRESSURE WILL DEVELOP OFF THE SOUTHEAST U.S. COAST TODAY AND DRIFT NORTHEAST AND AWAY FROM THE REGION ON FRIDAY. WEAK HIGH PRESSURE WILL EXTEND INTO THE AREA LATE FRIDAY INTO SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1100 AM THURSDAY... VERY WELL DEFINED WEDGE FRONT ASSOCIATED WITH A HYBRID COLD AIR DAMMING EVENT SHOWING UP NICELY IN OBSERVATIONS. TO THE SOUTHEAST...A COASTAL LOW IS DEVELOPING OFF THE COAST OF SC AND FURTHER ENHANCING THE WEDGE BOUNDARY. THIS WILL MAKE TEMPERATURE FORECASTS VERY TRICKY TODAY AS A VERY STRONG GRADIENT WILL BE PRESENT FROM WEST TO EAST WITH VERY COOL HIGHS IN THE WEST AND POTENTIALLY QUITE A BIT WARMER HIGHS IN THE EAST. FOR NOW HAVE MID 50S IN THE WEST AND UPPER 60S IN THE EAST BUT BY LATE IN THE AFTERNOON THIS COULD VERY WELL PAN OUT TO BE LOWER 50S IN THE WEST AND LOWER TO MID 70S IN THE EASTERN TIER OF COUNTIES. PRECIPITATION CONTINUES ACROSS THE CENTRAL PIEDMONT AND THE NORTHEASTERN COUNTIES AIDED BY ISENTROPIC LIFT AND SOME UPPER LEVEL DIVERGENCE AS WE SIT UNDER THE LEFT EXIT REGION OF A 250 MB JET. PRECIPITATION SHOULD BEGIN TO TREND DOWNWARD HOWEVER AS ISENTROPIC LIFT WEAKENS AND SOME VERY DRY MID-LEVEL AIR TO THE NORTHEAST TRIES TO WORK SOUTHWESTWARD INTO THE CWA. THIS IS VERY EVIDENT ON THE SOUNDINGS WHERE THE KMHX SOUNDING HAS A 5 DEGREE DEWPOINT DEPRESSION AT 850 MB AND THE KWAL SOUNDING HAS A 33 DEGREE DEWPOINT DEPRESSION. AS PRECIPITATION MOVES NORTHEAST...COMPOSITE RADAR SHOWS EVAPORATION OF THE PRECIPITATION...MOST LIKELY CAUSED BY THE MID LEVEL DRY AIR. AS FAR AS CONVECTIVE ALLOWING MODELS ARE CONCERNED...ONLY ONE REALLY HAS A HANDLE OF THE CURRENT MODE OF PRECIP AND THAT IS THE HRRR WHICH DEPICTS THE CURRENT PATTERN VERY WELL. GOING INTO THIS AFTERNOON THE RAIN OVER THE CENTRAL PART OF THE CWA PUSHES NORTHEAST AND CHANCES ELSEWHERE DIMINISH THROUGH THE AFTERNOON TO JUST A FEW PATCHES OF DRIZZLE OR LIGHT RAIN BY THIS EVENING. CLOUDS SHOULD REMAIN OVERNIGHT...THUS MODERATING LOWS...MAINLY LOW TO MIDDLE 50S NW TO SE. && .SHORT TERM /FRIDAY AND FRIDAY NIGHT/... AS OF 317 AM THURSDAY... FRIDAY SHOULD SEE THE BEGINNING OF A SLOW IMPROVEMENT IN SKY CONDITION AND TEMPS. DEVELOPING (THOUGH WEAK) NW FLOW IN THE MID- UPPER LEVELS WILL BEGIN TO SCOUR THE CAD AIR MASS FROM ALOFT. STILL...RESIDUAL LOW LEVEL MOISTURE WILL REMAIN HIGH ENOUGH TO PRODUCE EXTENSIVE CLOUDINESS IN THE MORNING WITH SOME PARTIAL BREAKS DEVELOPING IN THE AFTERNOON. THIS HEATING ALONG WITH THE PASSAGE OF A WEAK MID LEVEL TROUGH MAY PROVIDE ENOUGH LIFT TO GENERATE AN ISOLATED SHOWER OR THUNDERSTORM ACROSS CENTRAL NC. TEMPS WILL BEGIN TO RECOVER FRIDAY THOUGH IF CLOUDS STICK AROUND A LOT LONGER THAN EXPECTED...MAX TEMPS MAY END UP BEING 3-5 DEGREES COOLER THAN CURRENTLY FORECAST...ESPECIALLY ACROSS THE NORTHERN PIEDMONT. MAX TEMPS FRIDAY LOW-MID 70S. FRIDAY NIGHT..PARTIAL CLEARING MAY LEAD TO THE DEVELOPMENT OF FOGGY CONDITIONS AFTER MIDNIGHT. MIN TEMPS 55-60. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 320 AM THURSDAY... SATURDAY AND SATURDAY NIGHT: MID LEVEL S/W RIDGING WILL LARGELY KEEP CENTRAL NC DRY ON SATURDAY AND SATURDAY NIGHT. HOWEVER... WITH AND EASTERLY TO SOUTHEASTERLY SURFACE FLOW DEVELOPING LATE SATURDAY ALONG WITH DAYTIME HEATING CANT COMPLETELY RULE OUT SOME AFTERNOON SHOWERS AND STORMS ACROSS FAR EASTERN PORTIONS OF THE AREA WHERE LOW LEVEL CONVERGENCE MAY BE ENHANCED SOME ALONG PERHAPS A SEABREEZE. THUS... WILL GO WITH A SLIGHT CHANCE FOR SHOWERS AND STORMS ACROSS OUR FAR EASTERN COUNTIES FOR SATURDAY AFTERNOON. WITH SKIES NOW EXPECTED TO BE AT LEAST PARTLY SUNNY AT TIMES WILL RAISE HIGH TEMPS A DEGREE OR TWO INTO THE UPPER 70S NW TO LOWER 80S SE. THE LATEST GFS/ECMWF/NAM NOW SHOW THE ONSET OF PRECIP DELAYED A GOOD 6 TO 12 HOURS FROM PREVIOUS FORECASTS. THUS... WILL NOT INTRODUCE POPS UNTIL CLOSE TO DAYBREAK... FIRST IN THE WEST THEN SPREADING EAST THROUGH THE DAY ON SUNDAY. WITH INCREASING SOUTHERLY LOW LEVEL FLOW AND CLOUD COVER ON SATURDAY NIGHT/EARLY SUNDAY MORNING EXPECT LOW TEMPS WILL ABOVE NORMAL... GENERALLY RANGING FROM THE MID 50S IN THE FAR NE (WHERE WE MAY SEE SOME CLEARING BRIEFLY WITH THE LOSS OF HEATING AND PRIOR TO THE INCREASING OF MID AND HIGH LEVEL CLOUDS COVER) TO GENERALLY NEAR 60 ELSEWHERE. SUNDAY THROUGH MONDAY NIGHT: GOOD MOISTURE TRANSPORT IS EXPECTED ON SUNDAY INTO SUNDAY NIGHT AS CLOSED LOW INVOF THE FOUR CORNERS REGION (CURRENTLY) SHIFT EASTWARD AND OPENS WHILE COMBINING WITH A NORTHERN STREAM TROUGH TO AMPLIFY THE MID/UPPER LEVEL FLOW ACROSS THE CENTRAL AND EASTERN PART OF THE COUNTRY LATE WEEKEND INTO EARLY NEXT WEEK. THIS WILL HELP TO DRIVE A LEAD DEEP MOIST AXIS THROUGH CENTRAL NC LATE SUNDAY THROUGH EARLY MONDAY MORNING. WITH STRONG SOUTHERLY LOW LEVEL FLOW WITH THIS SYSTEM AND EXCELLENT MOISTURE TRANSPORT WE SHOULD SEE A LARGE BAND OF SHOWER/ISOLATED STORMS AND HEAVY RAIN MOVE THROUGH CENTRAL NC LATE SUNDAY INTO SUNDAY NIGHT... WITH A MAIN THREAT OF HEAVY RAIN. ALTHOUGH GIVEN THE STRONG LOW LEVEL WIND FIELDS CAN COMPLETELY RULE OUT AT LEAST A STRONG WIND GUST OR TWO. BUT GIVEN THE RATHER WEAK INSTABILITY AND POOR DIURNAL TIMING FOR THE MOST PART ANY SEVERE THREAT SHOULD REMAIN LOW. HIGHS SHOULD BE COOLER SUNDAY WITH THE INCREASE IN CLOUDS AND EVENTUALLY PRECIP LATE IN THE DAY...EXPECT HIGHS TO BE IN THE MID TO UPPER 60S NW (WHERE WE COULD SEE A BRIEF CAD AIRMASS DEVELOP) TO THE MID 70S SE/E (MAYBE EVEN A FEW UPPER 70S SE). LOWS MONDAY MORNING SHOULD BE WARM FOR THIS TIME OF YEAR... EXPECT LOWS IN THE LOWER TO MID 60S. THE MAIN SURFACE COLD FRONT SHOULD MOVE THROUGH THE REGION LATE MONDAY INTO MONDAY EVENING. WHILE THE STRONGER MID AND LOW LEVEL FLOW WILL HAVE PUSHED TO THE EAST... WE SHOULD SEE INSTABILITY INCREASE AS SOME DRIER MID LEVEL AIR WORKS INTO THE AREA FROM THE SOUTHWEST ON MONDAY MORNING/AFTERNOON. THIS SHOULD HELP TO YIELD AT LEAST SOME DESTABILIZATION AHEAD OF THE FRONT ON MONDAY RESULTING IN ISOLATED TO SCATTERED SHOWER AND STORMS MONDAY AFTERNOON/EVENING IN ADVANCE OF THE FRONT... WITH POSSIBLY A FEW STRONG TO MAYBE SEVERE STORMS (AS DEEP LAYER SHEAR WILL STILL BE AROUND 25 TO 35 KTS). BEST CHANCE OF ANY SVR AT THIS TIME (KEEP IN MIND WE ARE STILL A WAYS OUT IN TIME) WOULD BE ACROSS EASTERN PORTIONS OF THE AREA. HIGHS MONDAY ARE EXPECTED TO BE IN THE 70S TO LOWER 80S EAST/SOUTHEAST. LOWS TUESDAY MORNING RANGING FROM THE MID 50S NW TO AROUND 60 SE. TUESDAY THROUGH WEDNESDAY: DRIER WEATHER IS EXPECTED BEHIND THE FRONT ON TUESDAY AND WEDNESDAY... WITH A MUCH DRIER AIRMASS ADVECTING INTO THE REGION. HIGH TEMPS SHOULD BE NEAR NORMAL GENERALLY IN THE 70S... WITH LOWS IN THE 40S AND 50S. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... AS OF 747 AM THURSDAY... AN UNSETTLED WEATHER PATTERN WILL CONTINUE ACROSS CENTRAL NC THROUGH THE REMAINDER OF THE WORK WEEK. A BRIEF RESPITE FROM THE SUB VFR CONDITIONS EXPECTED SATURDAY BEFORE A LOW PRESSURE SYSTEM AFFECTS OUR REGION SUNDAY. SFC HIGH PRESSURE WILL CONTINUE TO EXTEND ACROSS CENTRAL NC TODAY THROUGH EARLY FRIDAY...KEEPING A COOL MOIST STABLE AIR MASS IN PLACE. UPPER LEVEL DISTURBANCES TRAVERSING OVERHEAD WILL CAUSE PERIODS OF PATCHY LIGH RAIN THROUGH THIS AFTERNOON. THE FLOW ALOFT WILL BECOME MORE WESTERLY AND EVENTUALLY NWLY BY LATE FRIDAY. MEANWHILE THE SFC RIDGE WILL WEAKEN. THIS WILL LEAD TO A SLOW IMPROVEMENT IN AVIATION CONDITIONS THROUGH FRIDAY NIGHT. EXPECT LOW END VFR/MVFR CEILINGS TO PERSIST THROUGH EARLY FRIDAY. PATCHES OF LIGHT RAIN WILL OCCUR THROUGH EARLY AFTERNOON THEN DIMINISH. AFTER SUNSET...CEILINGS WILL BECOME IFR OVER MOST OF THE AREA AND REMAIN IFR UNTIL MID MORNING FRIDAY. MOST LOCATIONS SHOULD SEE VFR CONDITIONS FRIDAY AFTERNOON...PERSISTING THROUGH SATURDAY. A LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST LATE SATURDAY AND AFFECT OUR REGION SUNDAY THROUGH EARLY MONDAY. THIS SYSTEM WILL BRING A HIGH PROBABILITY OF SHOWERS AND SUB VFR CEILINGS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...ELLIS SHORT TERM...WSS LONG TERM...BSD AVIATION...WSS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
134 AM EDT THU APR 16 2015 .SYNOPSIS... LOW PRESSURE WILL DEVELOP ALONG A FRONT STALLED ALONG THE GEORGIA COAST TONIGHT...SLOWLY WEAKENING LATE THURSDAY AND FRIDAY. HIGH PRESSURE OVER NEW ENGLAND WILL SHIFT EAST AND OFFSHORE THURSDAY. A WARM FRONT WILL MOVE NORTH THROUGH THE CAROLINAS ON SUNDAY WITH A COLD FRONT TO FOLLOW MONDAY NIGHT INTO TUESDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 130 AM THURSDAY...NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS: THE WEATHER SITUATION IS UNFOLDING PRETTY MUCH AS EXPECTED. THE SOLID MASS OF RAIN HAS CLEARED THE PEE DEE COUNTIES BUT RAIN CONTINUES TO FALL ACROSS WHITEVILLE...SOUTHPORT AND WILMINGTON. THIS AREA SHOULD MOVE OFF THE COAST IN THE NEXT 2 HOURS...LEAVING MUCH WEAKER FORCING FOR THE OVERNIGHT NIGHT. LATEST HRRR AND HRRRMODELS STILL SUGGEST THE BEST POTENTIAL FOR OVERNIGHT RAIN WILL BE NORTH OF A LINE FROM FLORENCE TO DILLON...TO ELIZABETHTOWN AND BURGAW...COINCIDENT WITH THE BETTER 700 MB MOISTURE AND RESIDUAL ISENTROPIC LIFT ON THE SYNOPTIC MODELS. THERE IS ALSO SMALL POSITIVE ELEVATED INSTABILITY ON THE ORDER OF 100 J/KG WHICH COULD HELP SUPPORT SHOWERS GIVEN SUFFICIENT SYNOPTIC TRIGGERING. FEW CHANGES ARE NEEDED TO LOW TEMPERATURE FORECASTS OR WINDS. DISCUSSION FROM 730 PM FOLLOWS... A STALLED FRONT JUST SOUTH OF SAVANNAH WILL DEVELOP AN AREA OF LOW PRESSURE IN THE NEXT FEW HOURS. THIS LOW WILL NOT STRAY TOO FAR OFFSHORE OVER THE NEXT 24 HOURS...BUT WILL MAINTAIN A STEADY NORTHEAST WIND. SURFACE HIGH PRESSURE OVER SOUTHEASTERN CANADA WILL SLIDE SOUTHEAST INTO NEW ENGLAND TONIGHT. THIS HIGH WILL EXTEND A RIDGE AXIS SOUTHWARD INTO THE CAROLINAS...COMPRESSING THE PRESSURE GRADIENT UP AGAINST THE LOW DEVELOPING OFF THE GEORGIA COAST. A COMPLEX UPPER LEVEL PATTERN ACROSS THE WESTERN U.S. HAS THE JET STREAM SPLIT INTO TWO SEGMENTS. THE SOUTHERN STREAM WILL BRING SEVERAL DISTURBANCES ACROSS THE CAROLINAS OVER THE NEXT 36-48 HOURS. ONE OF THESE DISTURBANCES IS MOVING ACROSS INTERSTATE 95 NOW PRODUCING THE LARGE SWATH OF RAIN NOW SEEN ON RADAR. THIS FEATURE SHOULD WORK ITS WAY TO THE COAST AROUND MIDNIGHT...AND I HAVE RAISED FORECAST POPS TO 100 PERCENT AREA-WIDE WITH 0.2 TO 0.4 INCHES OF RAIN EXPECTED OVER THE NEXT 12 HOURS. PLENTY OF MID- LEVEL MOISTURE SHOULD HANG AROUND AFTER MIDNIGHT WITH JUST ENOUGH WEAK ISENTROPIC LIFT PLUS ELEVATED INSTABILITY TO MAINTAIN SHOWERS AFTER MIDNIGHT...ESPECIALLY NORTH OF FLORENCE AND MYRTLE BEACH. LOW-LEVEL NORTHEAST WINDS WILL DRAG COOLER AIR SOUTHWARD TONIGHT...WITH LOWS AWAY FROM THE COAST FALLING TO NEAR 50. VARYING DEGREES OF MARINE INFLUENCE WILL KEEP THE IMMEDIATE COAST WARMER WITH LOWS IN THE MID 50S POSSIBLE. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/... AS OF 300 PM WEDNESDAY...THE FORECAST HAS BECOME NO LESS COMPLICATED AND IN FACT...IN SOME RESPECTS...MODELS HAVE DIVERGED EVEN FURTHER IN THE LAST 24 HOURS. THE GFS SOLUTION LOOKS VERY DIFFERENT FROM PREVIOUS RUNS. THE NAM SOLUTION LOOKS SIMILAR TO PREVIOUS THINKING...BUT THE PROGRESSION OF OFFSHORE LOW PRESSURE IS SLOWER AND FURTHER EASTWARD THAN 24 HOURS AGO AND CERTAINLY MUCH STRONGER. THE CANADIAN IS CONSIDERABLY SLOWER AND WEAKER THAN THE NAM AS IS THE EUROPEAN...BUT BOTH DO CLOSE OFF LOW PRESSURE ALONG THE COAST OF SOUTH CAROLINA. SLOWER SEEMS REASONABLE GIVEN THE STRENGTH OF HIGH PRESSURE TO THE NORTH AND RESULTING WEDGE...THUS THE BEST WE CAN DO AT THIS POINT IS TO GO ALONG WITH PERSISTENCE...BUT SLOW PROGRESSION. WILL INCLUDE HIGHEST POPS THU ALONG THE COAST AND UP TO CATEGORICAL THU MORNING ALONG THE CAPE FEAR COAST DUE TO STRENGTH OF ISENTROPIC LIFT COUPLED WITH THE LIFT ASSOCIATED WITH LOW PRESSURE/TROUGH. WILL THEN TREND POPS LOWER THU AFTERNOON AND NIGHT FROM SW TO NE WITH A LINGERING RISK ALONG THE CAPE FEAR COAST FRI MORNING. GIVEN PROXIMITY OF COASTAL TROUGH AND ELEVATED INSTABILITY...WILL INCLUDE MENTION OF THUNDER FOR PORTIONS OF THE FORECAST AREA. THE MOISTURE PROFILES DRY OUT CONSIDERABLY AS A RIDGE OF HIGH PRESSURE ALOFT BUILDS TO THE COAST FROM THE WEST TOWARD THE END OF THE PERIOD. WILL FINALLY DROP POPS BELOW THRESHOLD FRI AFTERNOON AND NIGHT...EVEN ALONG THE SEABREEZE BOUNDARY. BELOW NORMAL HIGH TEMPS ARE EXPECTED AGAIN ON THU AS WEDGE KEEPS LOW- LEVEL MOISTURE TRAPPED BENEATH INVERSION. HIGHS WILL ONLY BE IN THE LOWER TO MID 60S. DEVELOPING SUNSHINE ON FRI SHOULD ALLOW TEMPS TO RETURN TO MORE SEASONABLE LEVELS...LOW AND MID 70S. LOWS THIS PERIOD WILL BE MAINLY IN THE 50S. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 300 PM WEDNESDAY...GUIDANCE HAS SHIFTED PRETTY DRAMATICALLY FROM JUST YESTERDAY...LEADING TO ENHANCED UNCERTAINTY DURING THE EXTENDED. LARGE CLOSED LOW ACROSS THE SOUTHWEST WILL ONLY VERY SLOWLY FILL AND EJECT TO THE NORTHEAST THROUGH THE WEEKEND...PHASING WITH A DEEPENING NORTHERN STREAM CUTOFF LOW ACROSS THE GREAT LAKES LATE MONDAY. THIS FEATURE WILL THEN AMPLIFY AND STALL ACROSS THE GREAT LAKES THROUGH THE MIDDLE OF NEXT WEEK...PRODUCING 500MB HEIGHTS OF -2 TO -3 SD`S BELOW CLIMO ACROSS THE NORTHEAST AND INTO THE MID-ATLANTIC. INITIALLY THE EXTENDED WILL BE WARM AND PLEASANT. SATURDAY IS SHAPING UP TO BE A GORGEOUS DAY LOCALLY...WITH HIGHS ABOVE CLIMO AND A LOT OF SUNSHINE. MOISTURE RETURNS SUNDAY IN A PRE-FRONTAL AIR MASS WHICH WILL CONTINUE INTO MONDAY AHEAD OF A COLD FRONT. SUNDAY AND MONDAY WILL BOTH FEATURE ABOVE CLIMO TEMPS...BUT WITH INCREASING RAIN CHANCES AHEAD OF THE COLD FRONT. ATTM THE FRONT DOES NOT LOOK TO BE STRONGLY FORCED SO WIDESPREAD CONVECTION IS NOT ANTICIPATED MONDAY EVENING WITH THE FROPA. COOLER HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT FOR TUE/WED OF NEXT WEEK WITH TEMPS RETURNING TO SEASONABLE LEVELS. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... AS OF 06Z...EXPECTING IFR CONDITIONS MUCH OF THE TAF PERIOD WITH OCCASIONAL RAIN. COULD BE A BREAK IN THE 20 TO 02Z WINDOW WITH MVFR OR VFR CONDITIONS UNTIL THE NEXT BATCH OF PRECIPITATION ARRIVES TOWARD THE END OF THE PERIOD. WITH LOW PRESSURE OFF THE COAST...GUSTY NE WINDS ARE EXPECTED THROUGH MUCH OF THE PERIOD AS WELL WITH SPEEDS IN THE 10 TO 15 KT RANGE WITH WITHS OVER 20 KT...ESPECIALLY COASTAL TERMINALS. EXTENDED OUTLOOK...PREDOMINATELY IFR CONDITIONS ARE EXPECTED INTO EARLY FRIDAY MORNING WITH THE WEDGE. IMPROVING CONDITIONS DURING THE DAY FRI. DETERIORATING CONDITIONS AGAIN SATURDAY NIGHT THROUGH SUNDAY WITH A SLOW MOVING FRONT. SLIGHT CHANCE FOR SHOWERS MONDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 130 AM THURSDAY...NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS: STRONG NE WINDS HAVE QUICKLY DEVELOPED THIS EVENING. RECENT WIND GUSTS INCLUDE 31 KNOTS AT SPRINGMAID PIER IN MYRTLE BEACH...24 KNOTS ON BALD HEAD ISLAND...AND 23 KNOTS AT WRIGHTSVILLE BEACH. SEAS OUT AT THE FRYING PAN SHOALS BUOY HAVE ALREADY REACHED 8 FEET...WITH SEAS NOW PASSING 5 FEET AT BOTH NEARSHORE BUOYS NEAR CAPE FEAR. THIS UPDATE BACKED WINDS AROUND MORE NORTHERLY NEARSHORE AND INCREASE SEA HEIGHTS SLIGHTLY...ALL BASED ON CURRENT OBSERVATIONS. DISCUSSION FROM 730 PM FOLLOWS... A FRONT STALLED JUST SOUTH OF SAVANNAH EXTENDS EAST WELL OFF THE COAST. WEAK LOW PRESSURE WILL DEVELOP ALONG THE FRONT TONIGHT...WHILE HIGH PRESSURE OVER NEW ENGLAND RIDGES SOUTHWARD DOWN THE COAST. THE CAROLINAS WILL BE CAUGHT IN BETWEEN THESE TWO SYSTEMS...WITH INCREASING EAST-NORTHEAST WINDS THE RESULT. THE 18Z GFS APPEARS TO BE THE BEST INITIALIZED OF OUR MODELS THIS EVENING...AND ITS FORECAST WINDS HAPPEN TO BE THE STRONGEST TONIGHT...INDICATING WINDS NEARSHORE INCREASING TO 20-25 KT AND 25-30 KT AWAY FROM SHORE. THIS IS SLIGHTLY HIGHER THAN THE PREVIOUS FORECAST HAD. LATEST CHECK OF BUOYS INDICATES SEAS ARE INCREASING A BIT FASTER THAN EARLIER THOUGHT. I HAVE ADDED ABOUT ONE FOOT TO THE PREVIOUS FORECAST...WITH SEAS NOW EXPECTED TO BUILD TO 6-8 FEET OUT AT 20 MILES DISTANCE FROM SHORE...WITH 4-7 FEET EXPECTED CLOSER TO SHORE. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 PM WEDNESDAY...ONGOING SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED AT THE BEGINNING OF THE PERIOD AS LOW PRESSURE MOVES UP THE SOUTHEAST COAST. THE PRESSURE GRADIENT BETWEEN DEVELOPING LOW PRESSURE AND THE STRONG HIGH TO THE NORTH WILL ALLOW A TIGHT PRESSURE GRADIENT TO PERSIST INTO THU AND THIS IS WHEN WE EXPECT THE STRONGEST WINDS AND HIGHEST SEAS...UP TO 20 TO 30 KT...HIGHEST NORTHERN WATERS AND SEAS UP TO 5 TO 8 FT THROUGHOUT. AS THE PRESSURE GRADIENT SLACKENS AND LOW PRESSURE MOVES TO OUR N...WINDS AND SEAS WILL SUBSIDE THU NIGHT AND FRI WITH THIS TREND PERSISTING INTO FRI NIGHT. ENE WINDS THU WILL BACK TO NE THU NIGHT WITH NNE TO NE WINDS THEN PERSISTING THROUGH THE END OF THE PERIOD. LONG TERM /SATURDAY THROUGH MONDAY/... AS OF 300 PM WEDNESDAY...HIGH PRESSURE WILL BUILD DOWN THE COAST AND THEN MOVE OFFSHORE SATURDAY...CREATING A WEAK PRESSURE GRADIENT AND WINDS SHIFTING FROM NE EARLY...TO E/SE LATE. WINDS SPEEDS THEN STEADILY INCREASE SUNDAY AS THE GRADIENT STARTS TO PINCH AHEAD OF AN APPROACHING COLD FRONT...BECOMING S/SW AT AROUND 15 KTS MOST OF SUNDAY...AND THEN SW AT 15-20 KTS ON MONDAY DIRECTLY AHEAD OF THE FROPA. COLD FRONT WILL CROSS THE WATERS AT THE VERY END OF THE PERIOD WITH A WIND SHIFT TO THE NW AT 10-15 KTS. ALTHOUGH A WEAK SE GROUND SWELL WILL BE PRESENT IN THE SPECTRUM DURING THE EXTENDED...MUCH OF THE WAVE AMPLITUDE WILL BE FORMED VIA WIND WAVES...AND SEAS WILL BE 2-3 FT SATURDAY...BUILDING TO 3-5 FT SUNDAY AND MONDAY AHEAD OF THE COLD FRONT. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR AMZ250-252-254- 256. && $$ SYNOPSIS...RJD NEAR TERM...REK/TRA SHORT TERM...RJD LONG TERM...JDW AVIATION...RAN MARINE...REK/RJD/TRA/JDW
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1227 AM CDT THU APR 16 2015 .UPDATE... ISSUED AT 1227 AM CDT THU APR 16 2015 MINOR CHANGES THIS UPDATE. KEPT CHANCES OF RAIN SHOWERS SOUTHWEST...BUT APPARENT FORCING ALONG THE SLOW-MOVING COLD FRONT IN CENTRAL NORTH DAKOTA IS NOT ENOUGH TO SUSTAIN SHOWERS. MINOR CHANGES IN HOURLY TEMPERATURE TRENDS. UPDATE ISSUED AT 923 PM CDT WED APR 15 2015 RADAR ECHOS ACROSS THE FAR SOUTHWEST...OTHERWISE DRY SO ONCE AGAIN SCALED BACK ON POPS FOR THIS UPDATE. OTHER EDITS MINOR. UPDATE ISSUED AT 808 PM CDT WED APR 15 2015 WILL ALLOW THE RED FLAG TO EXPIRE AS SCHEDULED WITH WINDS TAPERING OFF AND RH VALUES QUICKLY INCREASING. UPDATE ISSUED AT 720 PM CDT WED APR 15 2015 SCALED BACK ON POPS A BIT WITH A VOID OF ANY SORT OF DECENT RADAR RETURNS ACROSS NORTH DAKOTA. ALLOWED THE WIND ADVISORY TO EXPIRE AS WE ARE NOW BELOW ADVISORY CRITERIA EAST...AND WITH WINDS EXPECTED TO QUICKLY TAPER OFF FURTHER OVER THE NEXT HOUR OR SO. STRONG UPPER LEVEL LOW PRESSURE CONTINUES TO SPIN JUST WEST OF THE CENTRAL ROCKIES. ENERGY ROTATING AROUND THE LOW WILL SPIRAL NORTH ACROSS THE WESTERN DAKOTAS AND SHOULD BRING SOME LIGHT RAIN. BAND OF ENHANCED RADAR RETURNS CURRENTLY LIFTING NORTH ACROSS WESTERN SOUTH DAKOTA TOWARDS MY SOUTHWEST. WITH T/TD SPREADS 20-30F...WILL KEEP POPS BELOW LIKELY FOR NOW AND CONTINUE TO MONITOR. RED FLAG WARNING WILL BE ALLOWED TO EXPIRE AT 01Z...ROUGHLY 45-50 MINUTES FROM NOW...AS WINDS TAPER OFF AND RH VALUES INCREASE. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 251 PM CDT WED APR 15 2015 FIRE WEATHER CONCERNS HIGHLIGHT THE SHORT TERM TONIGHT BUT WILL DIMINISH TOMORROW. A COLD FRONT ACROSS WESTERN NORTH DAKOTA HAS BEEN SLOWER TO MOVE EAST THAN EARLIER FORECAST. THE RESULT HAS BEEN AN EXTENDED PERIOD OF GUSTY SOUTHERLY WINDS ACROSS CENTRAL AND EASTERN NORTH DAKOTA UP THROUGH THIS AFTERNOON. THIS HAS RESULTED AN MULTIPLE FIRES ACROSS CENTRAL NORTH DAKOTA. IMPROVING CONDITIONS WILL FINALLY ARRIVE THIS EVENING AS THE FRONTAL BOUNDARY MOVES TO CENTRAL NORTH DAKOTA THEN TO THE EAST AFTER MIDNIGHT. THIS WILL BRING AN END TO THE STRONG SOUTHERLY WINDS. CLOUDS ARE BEING DRAWN UP THROUGH EASTERN SOUTH DAKOTA WITH SOME LIMITED LOW LEVEL MOISTURE. THE HRRR DOES GENERATE SOME LIGHT PRECIP ACROSS THE EAST...BUT GENERALLY EAST OF THE JAMES RIVER VALLEY THOUGH. MEASURABLE PRECIPITATION WILL BE MOST LIKELY ACROSS THE SOUTHWEST TONIGHT. BUT KEPT THE POPS LESS THAN 40 PERCENT. ON THURSDAY...COOLER TEMPERATURES WITH HIGHS 60 TO 65. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 251 PM CDT WED APR 15 2015 A WEAK COLD FRONTAL BOUNDARY SHIFTING THROUGH NORTHERN NORTH DAKOTA LATE THURSDAY NIGHT WILL UNDERGO FRONTOLYSIS AS IT SAGS SOUTH INTO CENTRAL NORTH DAKOTA FRIDAY MORNING. SPLIT FLOW REMAINS OVER NORTH DAKOTA FRIDAY WITH THE NORTHERN STREAM JUST GRAZING FAR NORTHERN NORTH DAKOTA/TURTLE MOUNTAINS. A CLOSED LOW OVER COLORADO SLOWLY EMERGES INTO THE CENTRAL PLAINS...WITH NORTH DAKOTA CAUGHT BETWEEN THESE TWO STREAMS FRIDAY AND WILL MOSTLY REMAIN IN A LULL FRIDAY WITH BENIGN WEATHER. FOR SATURDAY AND SATURDAY NIGHT...MODEL DATA CONTINUES TO SUGGEST SOME INTERACTION WITH THE CLOSED LOW AND ITS ASSOCIATED MOISTURE SPINNING INTO SOUTHERN NORTH DAKOTA...AND A STRONG SHORTWAVE TROUGH/SURFACE COLD FRONT VIA THE NORTHERN STREAM AS IT APPROACHES WESTERN NORTH DAKOTA 00Z SUNDAY. VARYING SOLUTIONS AS TO THE TIMING AND AREAL COVERAGE OF PRECIPITATION THAT IS FORECAST TO PUSH INTO NORTH DAKOTA SATURDAY AFTERNOON INTO SATURDAY NIGHT. THE GFS REPRESENTS THE FASTEST AND MOST WIDESPREAD PRECIPITATION SOLUTIONS...WITH CHANCES OF RAIN CROSSING THE SOUTHERN BORDER BEFORE 12Z SATURDAY. THE GEM/ECMWF REPRESENT SLOWER SOLUTIONS AND ARE MORE IN LINE WITH RAIN SHOWERS MAINLY CONFINED TO THE JAMES RIVER VALLEY AND PORTIONS OF SOUTH CENTRAL NORTH DAKOTA LATE SATURDAY AFTERNOON THROUGH SUNDAY MORNING. A COLD THERMAL TROUGH/POCKET IS FORECAST TO FOLLOW SUNDAY NIGHT THROUGH MOST OF NEXT WEEK. GOOD AGREEMENT BETWEEN THE GFS AND ECMWF WITH THIS IDEA. 850MB TEMPS ARE FORECAST TO RANGE BETWEEN -2C TO -8C THROUGH THURSDAY. THIS WILL TRANSLATE TO AFTERNOON HIGH TEMPERATURES IN THE UPPER 40S TO MID 50S. CONCERNING FIRE WEATHER IN THE LONG TERM PERIOD...NOT ANTICIPATING ANY FIRE WEATHER CONCERNS FRIDAY OR SATURDAY. DESPITE A COOLING TREND SUNDAY ONWARD...STRONG WINDS AT TIMES WILL ALIGN WITH LOW RELATIVE HUMIDITIES ACROSS PORTIONS OF WESTERN AND CENTRAL NORTH DAKOTA AND WILL NEED TO MONITOR. STRONG NORTHWEST WINDS DEVELOPING BEHIND A COLD FRONT ACROSS WESTERN AND CENTRAL NORTH DAKOTA SUNDAY MAY WARRANT A WIND ADVISORY. IN ADDITION MINIMUM RELATIVE HUMIDITIES OF AROUND 25 PERCENT IN THE SOUTHWEST MAY ALSO WARRANT A FIRE WEATHER HEADLINE SUNDAY. THEN ON MONDAY THE STRONGEST WINDS AND LOWEST RELATIVE HUMIDITIES ARE ALIGNED IN SOUTH CENTRAL NORTH DAKOTA...THUS THIS REPRESENTS ANOTHER POTENTIAL FOR FIRE WEATHER HEADLINES. WEAKER WINDS ARE EXPECTED FOR TUESDAY AND WEDNESDAY WITH EVEN COOLER TEMPERATURES...WITH WIDESPREAD HIGHS IN THE 40S WEDNESDAY. NO SIGNIFICANT SYSTEMS/PRECIPITATION EVENTS SUNDAY THROUGH WEDNESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1227 AM CDT THU APR 16 2015 A COLD FRONT EXTENDED FROM NEAR BOTTINEAU/RUGBY TO NEAR KBIS TO KMBG WAS SLOWLY PROPAGATING EASTWARD ACROSS THE STATE. SOUTHERLY WINDS AT KJMS SHOULD BECOME NORTHWESTERLY AROUND 12Z. OTHERWISE NORTH TO NORTHWEST WINDS AT TAF SITES MUCH OF TODAY...BECOMING LIGHT AFT 00Z. VFR CIGS/VSBYS ARE EXPECTED THROUGHOUT THE PERIOD. && .FIRE WEATHER... ISSUED AT 808 PM CDT WED APR 15 2015 RED FLAG WARNING ALLOWED TO EXPIRE WITH COOLING TEMPERATURES AND RISING RELATIVE HUMIDITY. ON THURSDAY MINIMUM RELATIVE HUMIDITY WILL FALL INTO THE UPPER TEENS NORTHWEST. HOWEVER THE WINDS WILL BE MUCH LOWER. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JV SHORT TERM...WAA LONG TERM...KS AVIATION...JV FIRE WEATHER...NH
AREA FORECAST DISCUSSION
NWS NORMAN OK
334 PM CDT THU APR 16 2015 .DISCUSSION... THIS DISCUSSION WILL REMAIN FOCUSED ON THE SHORT TERM... THUNDERSTORM AND PRECIPITATION CHANCES FROM THIS EVENING THROUGH FRIDAY MORNING... OVERALL... GUIDANCE HAS DONE A POOR JOB IN HANDLING THE BKN/OVC LOW/MID STRATUS ACROSS THE BULK OF WRN AND CENTRAL OK AND WRN N TX. THROUGH 20Z... SOME SCATTERED CLEARING HAS FINALLY STARTED AS MORE STRATOCU/CLOUD STREETS HAVE DEVELOPED. THIS CLOUD COVER WILL CONTINUE TO PROMOTE A LACK OF INSTABILITY/BL MIXING ACROSS MOST OF WRN OK AND WRN N TX... BUT WITH THE RECENT TRANSITION TO STRATOCU... MIXING MAY FINALLY BE PICKING UP. THE EARLY AFTN CONVECTION ACROSS FAR NW OK AND INTO THE PANHANDLES APPEARED TO BE DRIVEN BY A FOCUSED REGION OF ISENTROPIC ASCENT... SUPPORTED BY A NARROW REGION OF 1500 J/KG INSTABILITY AND DIVERGENCE ALOFT GIVEN THE ORIENTATION OF THE UPPER LVL JET MAX ASSOCIATED WITH THE H500 LOW... WHICH CONTINUES TO SETTLE OVER THE FOUR CORNERS REGION. THE RECENT SEVERE CONVECTION IN THE PANHANDLES THAT DEVELOPED OVER THE PAST 1 TO 2 HOURS IS PRIMARILY FOCUSED ON THE DRYLINE/PSUEDO-FRONTAL BOUNDARY THAT DEVELOPED EARLIER. AT THE MOMENT... HOW CONVECTION WILL EVOLVE THROUGH THIS EVENING REMAINS A CHALLENGE. TRADITIONAL GUIDANCE CONTINUES TO STRUGGLE WITH HOW TO EVOLVE THE UPPER LOW AND CONVECTION. RECENT MESOSCALE GUIDANCE IS ABLE TO CATCH ON IN SPURTS... BUT IT STRUGGLES AS WELL. OVERALL... EXPECT CONVECTION ACROSS THE PANHANDLES TO CONTINUE TO TRANSITION EASTWARD... HOWEVER... RECENT OBS THROUGH 20Z SUGGEST THE DRYLINE MAY BE STARTING ITS GRADUAL RETREAT TO THE WEST. WITH THIS SAID... EXPECT THE SFC TROUGH/FRONT (IF WE CAN CALL IT THAT)... WILL CONTINUE TO LIFT E/NE INTO WRN OK THIS EVENING... WITH STORMS MOVING INTO NWRN OK AROUND 5 TO 7PM CDT. THE OVERALL EVOLUTION OF STORMS APPEAR TO HAVE BEEN CAPTURED ON THE RECENT HRRR (18Z RUN)... BUT THE TIMING MAY BE LATE... THE 12Z TTU WRF SEEMS TO HAVE A DECENT HANDLE ON TIMING... AS DOES THE WRF-NMM. NOT TO FOCUS SOLELY ON THE WRN ACTIVITY... STRONG CONVECTION HAS DEVELOPED ACROSS WEST CENTRAL TX THIS AFTN. CURRENT THOUGHTS HAVE THIS ACTIVITY LIFTING N/NE INTO WRN N TX AND THE RED RIVER VALLEY. RECENT MESOSCALE GUIDANCE SEEMS TO SUGGEST THIS ACTIVITY WILL LESSEN AFTER SUNSET AS IT REMAINS DRIVEN BY DIURNAL HEATING/INSTABILITY. AS FOR SEVERE STORMS THIS AFTN/EVENING ACROSS WRN OK/WRN N TX... STORMS THAT ARE ABLE TO MOVE IN OR DEVELOP WILL RESIDE WITHIN AN ENVIRONMENT SUPPORTIVE OF LARGE HAIL (GOLF BALLS) AND DAMAGING WINDS (60-70MPH). SEVERE POTENTIAL WILL WANE WITH ANY SCATTERED CONVECTION THAT PERSISTS INTO THE OVERNIGHT HOURS EASTWARD INTO CENTRAL OK BY FRIDAY MORNING. THE TORNADO THREAT OVER THE TX PANHANDLE WILL DIMINISH AS STORMS MOVE OFF THE DRYLINE AND INTO WRN OK... 0-1KM HELICITY DECREASES AND THE LACK OF A FOCUSING BOUNDARY DOES NOT BODE WELL FOR TORNADIC DEVELOPMENT ACROSS WRN OK AT THE MOMENT. JTK && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 59 74 59 77 / 40 50 60 30 HOBART OK 57 75 55 77 / 50 50 50 20 WICHITA FALLS TX 60 77 58 80 / 40 50 50 20 GAGE OK 54 74 51 76 / 70 50 50 20 PONCA CITY OK 58 74 58 75 / 30 60 70 50 DURANT OK 61 77 62 78 / 30 50 60 30 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1044 PM EDT FRI APR 17 2015 .SYNOPSIS... DRIER AND WARMER AIR WILL SPREAD INTO THE REGION THROUGH SATURDAY. A WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA SATURDAY NIGHT INTO SUNDAY...ACCOMPANIED BY ABUNDANT MOISTURE AND MORE RAINFALL. A COLD FRONT WILL CROSS THE AREA ON MONDAY...USHERING IN SEASONABLE TEMPERATURES AND DRY CONDITIONS. && .NEAR TERM /THROUGH SATURDAY/... AS OF 1030 PM EDT FRIDAY...WIDESPREAD SHOWERS STILL COVER THE UPSTATE AND PORTIONS OF THE MOUNTAINS...SO CONTINUING CATEGORICAL POPS FOR ANOTHER COUPLE OF HOURS UNTIL THE SHORTWAVE AXIS PUSHES THROUGH STILL LOOKS GOOD. TEMPERATURES ON TRACK FOR THE MOST PART SO ONLY MINOR TWEAKS TO HOURLY TRENDS. AS OF 730 PM EDT FRIDAY...HAVE BUMPED UP POPS ACROSS MOST OF THE AREA THIS EVENING INTO THE OVERNIGHT PERIOD TO ACCOUNT FOR FAIRLY WIDESPREAD LIGHT RAIN/SHOWERS MOVING ACROSS THE AREA...FORCED BY THE RELATIVELY STRONG SHORTWAVE MOVING ACROSS THE SOUTHEAST THIS EVENING. IF THE HRRR IS TO BE BELIEVED...THESE SHOWERS COULD LINGER OVERNIGHT AND PAST SUNRISE...AND WILL EVALUATE FURTHER FOR THE LATE EVENING UPDATE. BEST MOISTURE REMAINS ACROSS THE UPSTATE AND NORTHEAST GEORGIA BUT STILL SEEING SOME LIGHT RAIN ACROSS THE MOUNTAINS AND FOOTHILLS. STILL SEEING SOME SBCAPE VALUES HOLDING ON ACROSS THE PIEDMONT BUT THESE SHOULD BEGIN DROPPING RAPIDLY WITH SUNSET...SO HAVE PULLED BACK ON THUNDER WORDING THIS EVENING AND OVERNIGHT. OTHER GRIDS IN GOOD SHAPE FOR THE MOST PART...WITH ONLY MINOR TWEAKS TO ACCOUNT FOR HOURLY TRENDS. AS OF 430 PM EDT FRIDAY...VERY LITTLE CHANGE TO PREVIOUS THINKING FOR THE NEAR TERM. PRECIPITATION BEGINNING TO OVERSPREAD WESTERN AND SOUTHWESTERN ZONES AS EXPECTED. NEW GUIDANCE BEGINNING TO PULL BACK A LITTLE ON CONVECTIVE POTENTIAL...WITH INCREASING CLOUD COVER AND MOISTENING ATMOSPHERE WHAT LITTLE SBCAPE WAS BEGINNING TO CREEP INTO THE MESOANALYSES OVER THE PAST COUPLE OF HOURS IS ONCE AGAIN FALLING OFF. LOOKING AT HI-RES REFLECTIVITY FORECASTS...DEFINITELY STARTING TO LOOK LIKE MORE STRATIFORM RAIN OR SHOWERS WITH THE POSSIBILITY OF EMBEDDED THUNDER. HAVE LEFT WEATHER WORDING AS IS FOR NOW SINCE CURRENTLY ADVERTISED THUNDER IS CHANCE AT BEST...BUT WILL REEVALUATE MORE THOROUGHLY FOR NEXT NEAR-TERM UPDATE. ONLY MINOR TWEAKS TO TEMPS AND DEWPOINTS TO UPDATE TRENDS. AS OF 245 PM EDT FRIDAY...THE SYNOPTIC PATTERN HAS NOT CHANGED ALL THAT MUCH FROM YESTERDAY...OR DAYS PAST FOR THAT MATTER. IT STILL FEATURES ROTATING CLOSE UPPER LOW OVER THE FOUR CORNERS WHILE DEEP SOUTHWEST WAA PREVAILS ACROSS THE SOUTHEAST UNITED STATES. AT THE SURFACE...SPRINGTIME WEDGE STARTING TO ERODE AS EXPECTED THIS AFTERNOON AS WINDS HAVE VEERED SOUTHERLY ACROSS NORTHEAST GA AND THE UPSTATE...ALONG WITH A FEW LOCATIONS OVER THE NC PIEDMONT. FURTHERMORE...H5 SHORT WAVE AND ASSOCIATED VORTICITY MAXIMA CONTINUES TO SLIDE EAST ACROSS THE DEEP SOUTH WITH A BROAD AREA OF PRECIPITATION ACCOMPANYING. LATEST SPC MESO ANALYSIS NOT ALL THAT IMPRESSIVE AS INSTABILITY REMAINS NEARLY NONEXISTENT ACROSS THE FCST AREA. MODELS FAVOR IMPROVING LAPSE RATES WITH HEATING THIS AFTERNOON...HOWEVER STILL SKEPTICAL AS PRECIP SHIELD AND ASSOCIATED LOW OVERCAST SKY COVER WILL LIMIT HEATING. NEVERTHELESS...THE FCST DOES FEATURE INCREASING POPS THROUGH THE AFTERNOON/EVENING HOURS WITH CHANCES FOR THUNDER MENTIONED...AND WILL CONTINUE WITH SUCH IN THE HWO. POPS WILL LOWER AFTER MIDNIGHT AS THE PRIMARY UPPER WAVE EJECTS TO THE EAST...AND A WEAK/DRY BACK DOOR FRONT SLIDES SOUTHWARD ACROSS THE REGION. HELD ON TO TOKEN SLIGHT/CHANCE POPS THROUGH MORNING TO ACCOUNT FOR ANY RESIDUAL SHRA ALONG THE BOUNDARY. LATEST SOUNDINGS DO NOT SUGGEST AS MUCH MID DRYING AS THE PREVIOUS RUN...THEREFORE NOT ALL THAT CONFIDENT IN AREAS OF DENSE FOG OVERNIGHT. THAT SAID...WOULDNT BE SURPRISED TO SEE ISOLATED CASES OF SUCH ACROSS THE NC PIEDMONT/FOOTHILLS JUST AHEAD OF THE INTRUDING BOUNDARY WHEN WINDS ARE CALMEST AND THE PBL IS DECOUPLED. SATURDAY WILL BE HIGHLIGHTED BY DECREASING CLOUDINESS AS DOWNSLOPING FLOW PREVAILS AMONGST INCREASING HEIGHTS ALOFT AS AXIS OF SHORTWAVE RIDGE SHIFTS OVERHEAD. POPS WILL INCREASE YET AGAIN THROUGH THE DAY AS FCST SOUNDINGS INDICATE MODEST DESTABILIZATION WITH HEATING. HOWEVER EXPECTING UPPER RIDGING TO PROVIDE SOME SUBSIDENCE THEREFORE KEPT POPS AT OR BELOW CHANCE LEVELS THROUGH THE DAY. TEMPERATURES ON SATURDAY WILL DEPEND HIGHLY ON HOW SOON THE SKY COVER SCT OUT. TOOK A MIDDLE OF THE ROAD APPROACH AS IT PERTAINS TO GUIDANCE...WITH THE FCST FEATURING HIGHS 3-5 DEGREES ABOVE NORMAL. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... AS OF 200 PM FRIDAY...TWO AREAS OF CONCERN TO DEAL WITH IN THE SHORT TERM. THE FIRST WILL BE A PERIOD OF HEAVY RAIN ON SUNDAY AND THEN A RISK OF SEVERE STORMS ON MONDAY. THE UPPER RIDGE OVER THE SOUTHEAST U.S. WILL TRANSLATE EASTWARD SATURDAY NIGHT AS THE UPPER LOW THAT HAS BEEN OVER THE 4-CORNERS BEGINS TO MOVE EAST THANKS TO A DIGGING TROUGH MOVING SE OUT OF THE CANADIAN PRAIRIE. A SHORT WAVE OUT AHEAD OF THE UPPER LOW WILL MOVE NE FROM THE GULF COAST AND ACROSS THE WESTERN CAROLINAS AND NE GA ON SUNDAY. AT THE SURFACE...A WARM FRONT WILL APPROACH FROM THE SW ON SUNDAY. ALL OF THIS WILL RESULT IN ALL TYPES OF FORCING ACROSS THE REGION ON SUNDAY. PWATS WILL BE IN THE 1.5-1.7" RANGE WITH A 35-45 KT SELY 850 MB JET INTO THE BLUE RIDGE. WILL RAMP POPS UP QUICKLY TO CATEGORICAL FROM WEST TO EAST BY MIDDAY SUNDAY...THEN DECREASE RAPIDLY FROM WEST TO EAST LATE SUNDAY AS THE AXIS OF DEEP MOISTURE AND FORCING SHIFT EAST. HEAVY RAIN LOOKS TO BE A GOOD BET...BUT THE RELATIVELY QUICK MOVEMENT OF THE SYSTEM SHOULD PRECLUDE ANY SERIOUS HYDRO ISSUES. BLENDING THE MODEL CONSENSUS AND WPC QPF GUIDANCE... RESULTS IN GENERALLY 1.5"-2.0" FROM LATE SATURDAY NIGHT INTO SUNDAY NIGHT. THE HIGHEST AMOUNTS AS USUAL ARE EXPECTED TO BE NEAR THE BLUE RIDGE ESCARPMENT WHERE 2-3" OF RAIN CAN BE EXPECTED. THESE VALUES ARE UNDER THE 12 TO 24 HOUR FFG. THERE MAY BE SOME LOCALIZED FLOODING BUT WIDESPREAD FLOODING IS UNLIKELY. HOWEVER...WILL CONTINUE TO MENTION HEAVY RAIN IN THE HWO. AN IN SITU WEDGE WILL RESULT IN COOL TEMPS ON SUNDAY AND WILL THEREFORE TREND TOWARD CONSRAW GUIDANCE TEMPS. SOME DEGREE OF CLEARING SHOULD OCCUR SUNDAY NIGHT AS THE AXIS OF DEEP MOISTURE SHIFTS NE AND A DOWNSLOPE WIND COMPONENT THROUGH THE COLUMN DEVELOPS. ON MONDAY...A COLD FRONT WILL MOVE ACROSS THE REGION FROM WEST TO EAST. BOTH THE NAM AND GFS INDICATE THAT THE ATMOSPHERE WILL DESTABILIZE BY AFTERNOON WITH CAPES MOST LIKELY INCREASING TO BETWEEN 1000 AND 1500 J/KG PER GFS AND ECM. ALSO...0-6KM SHEAR INCREASES TO ABOUT 40KT. THIS MAY SUPPORT SOME ORGANIZATION TO THE CONVECTION AS THE COLD FRONT MOVES THROUGH. THE 12Z NAM MODEL REFLECTIVITY SUGGESTS THAT A BROKEN LINE OF CONVECTION WILL ACCOMPANY THE FRONT ACROSS THE AREA ON MONDAY WITH A FEW SEVERE STORMS POSSIBLE. WITH THE AREA SOLIDLY IN THE WARM SECTOR ON MONDAY...MAX TEMPS ARE EXPECTED TO BE ABOUT 5 DEGREES ABOVE CLIMO. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 245 PM FRIDAY...MONDAY NIGHT...SFC HIGH PRESSURE WILL BUILD OVER THE FORECAST AREA IN THE WAKE OF A PASSING COLD FRONT. 12Z GFS INDICATES THAT H85 TEMPERATURES WILL COOL BY 5 C FROM 0Z TO 12Z TUESDAY...A LITTLE LESS COOLING ON THE ECMWF. USING A BLEND OF GUIDANCE...I WILL FORECAST LOW TEMPERATURES FROM THE UPPER 40S WITHIN THE MTN VALLEYS TO MID 50S EAST. ON TUESDAY...BROAD HIGH PRESSURE WILL REMAIN ACROSS THE CWA. THE REGION SHOULD SEE MOSTLY SUNNY CONDITIONS WITH A LIGHT SOUTHWEST WIND. TEMPERATURES SHOULD RESPOND TO THE LATE APRIL SUN AND WEAK DOWNSLOPING...FORECAST TUES HIGHS SLIGHTLY ABOVE NORMAL. WEDNESDAY THROUGH FRIDAY...THE GFS AND ECMWF GENERALLY AGREE THAT A LARGE CLOSED MID LEVEL LOW WILL REMAIN ACROSS THE NORTHEAST AND EASTERN CANADA...AS A RIDGE LINGERS OVER THE SOUTHERN PLAINS. THE HEIGHTS ACROSS THE CWA WILL LIKELY REMAIN NW TO SE THROUGH THE PERIOD. THE MODELS ARE IN LESS AGREEMENT WITH THE PLACEMENT AND TIMING OF SFC FEATURES...PRIMARILY WEAK FRONTS AND PRESSURE CENTERS. I AM MORE CONFIDENT TIMING MID LEVEL FEATURES WITHIN THE NW FLOW ACROSS THE SOUTHERN APPALACHIANS...I WILL FAVOR THE ECMWF. OVERALL...I WILL KEEP CONDITIONS DRY ON WED...BUT MOISTURE WILL INCREASE THROUGH THE DAY. A SHORT SERIES OF MID LEVEL S/W ARE FORECAST TO RIPPLE ACROSS THE CWA THURSDAY THROUGH FRIDAY. TEMPERATURES SHOULD RANGE CLOSE TO NORMAL WITH AFTERNOON DEWPOINTS ONLY IN THE 40S. GIVEN THE TRACK OF THE MID LEVEL DISTURBANCES AND WEAK DIURNAL INSTABILITY...I WILL INDICATE ONLY SCHC POPS ACROSS THE MTNS ON THURSDAY. FORECAST SOUNDINGS SHOW GREATER INSTABILITY FRIDAY AFTERNOON...FROM THE MTNS TO THE PIEDMONT. THE COMBINATION OF THE PASSING DISTURBANCE AND INSTABILITY SHOULD SUPPORT SCT COVERAGE ACROSS THE MTNS AND ISO EAST. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... AT KCLT /03Z UPDATE/...CIGS A LITTLE SLOWER TO DROP THAN EARLIER ANTICIPATED SO HAVE DELAYED THE MVFR CIGS FOR ANOTHER HOUR OR SO...WITH -RA/-SHRA SLOWLY PUSHING EAST TOWARD THE AIRPORT UNDER THE INFLUENCE OF THE UPPER SHORTWAVE. ONCE THE DEEPER MOISTURE ARRIVES...CIGS SHOULD DROP TO MVFR. AS WINDS DECOUPLE OVERNIGHT...VSBYS SHOULD DROP TO MVFR AND POTENTIALLY LOWER EITHER BRIEFLY OR IN ISOLATED LOCATIONS...WITH CIGS DROPPING TO IFR. SLOW IMPROVING TREND ON SATURDAY WITH MVFR CIGS THROUGH THE PERIOD...THOUGH KCLT MAY BEGIN TO SEE SOME SCATTERING TOWARD THE END OF THE PERIOD. SW WINDS TO START WITH WEDGE CONTINUING TO ERODE... AND WINDS SHIFTING NNE AND NE SATURDAY IN THE WAKE OF THE UPPER WAVE AS A SURFACE HIGH PRESSURE AXIS PUSHES EAST OVER THE OHIO RIVER VALLEY. ELSEWHERE...AT KGSP/KGMU/KAND EXPECT AN OVERALL SIMILAR TREND TO KCLT BUT WITH -SHRA IN AT TAF INITIALIZATION AND CIGS DROPPING A LITTLE FASTER OVERNIGHT. KAVL/KHKY WILL SEE FEWER RESTRICTIONS BEING A LITTLE FARTHER NORTH FROM THE DEEP MOISTURE...AND IT IS POSSIBLE THAT KHKY MAY KEEP VFR CIGS THROUGH THE NIGHT THOUGH HAVE CONTINUED MVFR TREND WITH THIS ISSUANCE. MVFR VSBYS STILL LIKELY WITH SURFACE WINDS DROPPING OFF. ANY -TSRA TOO ISOLATED TO INCLUDE IN THE TAF AT THIS TIME. OUTLOOK...DRIER WEATHER IS FAVORED SATURDAY AFTERNOON. DEEPER MOISTURE WILL RETURN ALONG A WARM FRONT SAT NIGHT THROUGH SUNDAY...WITH HEAVY RAINFALL AND WIDESPREAD RESTRICTIONS LIKELY ONCE AGAIN. THUNDERSTORMS WILL THEN BE POSSIBLE THROUGH MONDAY AS A COLD FRONT REACHES THE AREA FROM THE WEST. CONFIDENCE TABLE... 02-08Z 08-14Z 14-20Z 20-00Z KCLT MED 69% MED 69% LOW 57% HIGH 100% KGSP MED 66% MED 62% LOW 51% HIGH 100% KAVL HIGH 92% HIGH 87% LOW 59% HIGH 97% KHKY HIGH 90% HIGH 98% MED 70% HIGH 100% KGMU MED 64% LOW 58% LOW 47% HIGH 100% KAND MED 61% MED 65% LOW 47% HIGH 87% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...CSH NEAR TERM...CDG/TDP SHORT TERM...LG LONG TERM...NED AVIATION...TDP
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
747 PM EDT FRI APR 17 2015 .SYNOPSIS... DRIER AND WARMER AIR WILL SPREAD INTO THE REGION THROUGH SATURDAY. A WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA SATURDAY NIGHT INTO SUNDAY...ACCOMPANIED BY ABUNDANT MOISTURE AND MORE RAINFALL. A COLD FRONT WILL CROSS THE AREA ON MONDAY...USHERING IN SEASONABLE TEMPERATURES AND DRY CONDITIONS. && .NEAR TERM /THROUGH SATURDAY/... AS OF 730 PM EDT FRIDAY...HAVE BUMPED UP POPS ACROSS MOST OF THE AREA THIS EVENING INTO THE OVERNIGHT PERIOD TO ACCOUNT FOR FAIRLY WIDESPREAD LIGHT RAIN/SHOWERS MOVING ACROSS THE AREA...FORCED BY THE RELATIVELY STRONG SHORTWAVE MOVING ACROSS THE SOUTHEAST THIS EVENING. IF THE HRRR IS TO BE BELIEVED...THESE SHOWERS COULD LINGER OVERNIGHT AND PAST SUNRISE...AND WILL EVALUATE FURTHER FOR THE LATE EVENING UPDATE. BEST MOISTURE REMAINS ACROSS THE UPSTATE AND NORTHEAST GEORGIA BUT STILL SEEING SOME LIGHT RAIN ACROSS THE MOUNTAINS AND FOOTHILLS. STILL SEEING SOME SBCAPE VALUES HOLDING ON ACROSS THE PIEDMONT BUT THESE SHOULD BEGIN DROPPING RAPIDLY WITH SUNSET...SO HAVE PULLED BACK ON THUNDER WORDING THIS EVENING AND OVERNIGHT. OTHER GRIDS IN GOOD SHAPE FOR THE MOST PART...WITH ONLY MINOR TWEAKS TO ACCOUNT FOR HOURLY TRENDS. AS OF 430 PM EDT FRIDAY...VERY LITTLE CHANGE TO PREVIOUS THINKING FOR THE NEAR TERM. PRECIPITATION BEGINNING TO OVERSPREAD WESTERN AND SOUTHWESTERN ZONES AS EXPECTED. NEW GUIDANCE BEGINNING TO PULL BACK A LITTLE ON CONVECTIVE POTENTIAL...WITH INCREASING CLOUD COVER AND MOISTENING ATMOSPHERE WHAT LITTLE SBCAPE WAS BEGINNING TO CREEP INTO THE MESOANALYSES OVER THE PAST COUPLE OF HOURS IS ONCE AGAIN FALLING OFF. LOOKING AT HI-RES REFLECTIVITY FORECASTS...DEFINITELY STARTING TO LOOK LIKE MORE STRATIFORM RAIN OR SHOWERS WITH THE POSSIBILITY OF EMBEDDED THUNDER. HAVE LEFT WEATHER WORDING AS IS FOR NOW SINCE CURRENTLY ADVERTISED THUNDER IS CHANCE AT BEST...BUT WILL REEVALUATE MORE THOROUGHLY FOR NEXT NEAR-TERM UPDATE. ONLY MINOR TWEAKS TO TEMPS AND DEWPOINTS TO UPDATE TRENDS. AS OF 245 PM EDT FRIDAY...THE SYNOPTIC PATTERN HAS NOT CHANGED ALL THAT MUCH FROM YESTERDAY...OR DAYS PAST FOR THAT MATTER. IT STILL FEATURES ROTATING CLOSE UPPER LOW OVER THE FOUR CORNERS WHILE DEEP SOUTHWEST WAA PREVAILS ACROSS THE SOUTHEAST UNITED STATES. AT THE SURFACE...SPRINGTIME WEDGE STARTING TO ERODE AS EXPECTED THIS AFTERNOON AS WINDS HAVE VEERED SOUTHERLY ACROSS NORTHEAST GA AND THE UPSTATE...ALONG WITH A FEW LOCATIONS OVER THE NC PIEDMONT. FURTHERMORE...H5 SHORT WAVE AND ASSOCIATED VORTICITY MAXIMA CONTINUES TO SLIDE EAST ACROSS THE DEEP SOUTH WITH A BROAD AREA OF PRECIPITATION ACCOMPANYING. LATEST SPC MESO ANALYSIS NOT ALL THAT IMPRESSIVE AS INSTABILITY REMAINS NEARLY NONEXISTENT ACROSS THE FCST AREA. MODELS FAVOR IMPROVING LAPSE RATES WITH HEATING THIS AFTERNOON...HOWEVER STILL SKEPTICAL AS PRECIP SHIELD AND ASSOCIATED LOW OVERCAST SKY COVER WILL LIMIT HEATING. NEVERTHELESS...THE FCST DOES FEATURE INCREASING POPS THROUGH THE AFTERNOON/EVENING HOURS WITH CHANCES FOR THUNDER MENTIONED...AND WILL CONTINUE WITH SUCH IN THE HWO. POPS WILL LOWER AFTER MIDNIGHT AS THE PRIMARY UPPER WAVE EJECTS TO THE EAST...AND A WEAK/DRY BACK DOOR FRONT SLIDES SOUTHWARD ACROSS THE REGION. HELD ON TO TOKEN SLIGHT/CHANCE POPS THROUGH MORNING TO ACCOUNT FOR ANY RESIDUAL SHRA ALONG THE BOUNDARY. LATEST SOUNDINGS DO NOT SUGGEST AS MUCH MID DRYING AS THE PREVIOUS RUN...THEREFORE NOT ALL THAT CONFIDENT IN AREAS OF DENSE FOG OVERNIGHT. THAT SAID...WOULDNT BE SURPRISED TO SEE ISOLATED CASES OF SUCH ACROSS THE NC PIEDMONT/FOOTHILLS JUST AHEAD OF THE INTRUDING BOUNDARY WHEN WINDS ARE CALMEST AND THE PBL IS DECOUPLED. SATURDAY WILL BE HIGHLIGHTED BY DECREASING CLOUDINESS AS DOWNSLOPING FLOW PREVAILS AMONGST INCREASING HEIGHTS ALOFT AS AXIS OF SHORTWAVE RIDGE SHIFTS OVERHEAD. POPS WILL INCREASE YET AGAIN THROUGH THE DAY AS FCST SOUNDINGS INDICATE MODEST DESTABILIZATION WITH HEATING. HOWEVER EXPECTING UPPER RIDGING TO PROVIDE SOME SUBSIDENCE THEREFORE KEPT POPS AT OR BELOW CHANCE LEVELS THROUGH THE DAY. TEMPERATURES ON SATURDAY WILL DEPEND HIGHLY ON HOW SOON THE SKY COVER SCT OUT. TOOK A MIDDLE OF THE ROAD APPROACH AS IT PERTAINS TO GUIDANCE...WITH THE FCST FEATURING HIGHS 3-5 DEGREES ABOVE NORMAL. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... AS OF 200 PM FRIDAY...TWO AREAS OF CONCERN TO DEAL WITH IN THE SHORT TERM. THE FIRST WILL BE A PERIOD OF HEAVY RAIN ON SUNDAY AND THEN A RISK OF SEVERE STORMS ON MONDAY. THE UPPER RIDGE OVER THE SOUTHEAST U.S. WILL TRANSLATE EASTWARD SATURDAY NIGHT AS THE UPPER LOW THAT HAS BEEN OVER THE 4-CORNERS BEGINS TO MOVE EAST THANKS TO A DIGGING TROUGH MOVING SE OUT OF THE CANADIAN PRAIRIE. A SHORT WAVE OUT AHEAD OF THE UPPER LOW WILL MOVE NE FROM THE GULF COAST AND ACROSS THE WESTERN CAROLINAS AND NE GA ON SUNDAY. AT THE SURFACE...A WARM FRONT WILL APPROACH FROM THE SW ON SUNDAY. ALL OF THIS WILL RESULT IN ALL TYPES OF FORCING ACROSS THE REGION ON SUNDAY. PWATS WILL BE IN THE 1.5-1.7" RANGE WITH A 35-45 KT SELY 850 MB JET INTO THE BLUE RIDGE. WILL RAMP POPS UP QUICKLY TO CATEGORICAL FROM WEST TO EAST BY MIDDAY SUNDAY...THEN DECREASE RAPIDLY FROM WEST TO EAST LATE SUNDAY AS THE AXIS OF DEEP MOISTURE AND FORCING SHIFT EAST. HEAVY RAIN LOOKS TO BE A GOOD BET...BUT THE RELATIVELY QUICK MOVEMENT OF THE SYSTEM SHOULD PRECLUDE ANY SERIOUS HYDRO ISSUES. BLENDING THE MODEL CONSENSUS AND WPC QPF GUIDANCE... RESULTS IN GENERALLY 1.5"-2.0" FROM LATE SATURDAY NIGHT INTO SUNDAY NIGHT. THE HIGHEST AMOUNTS AS USUAL ARE EXPECTED TO BE NEAR THE BLUE RIDGE ESCARPMENT WHERE 2-3" OF RAIN CAN BE EXPECTED. THESE VALUES ARE UNDER THE 12 TO 24 HOUR FFG. THERE MAY BE SOME LOCALIZED FLOODING BUT WIDESPREAD FLOODING IS UNLIKELY. HOWEVER...WILL CONTINUE TO MENTION HEAVY RAIN IN THE HWO. AN IN SITU WEDGE WILL RESULT IN COOL TEMPS ON SUNDAY AND WILL THEREFORE TREND TOWARD CONSRAW GUIDANCE TEMPS. SOME DEGREE OF CLEARING SHOULD OCCUR SUNDAY NIGHT AS THE AXIS OF DEEP MOISTURE SHIFTS NE AND A DOWNSLOPE WIND COMPONENT THROUGH THE COLUMN DEVELOPS. ON MONDAY...A COLD FRONT WILL MOVE ACROSS THE REGION FROM WEST TO EAST. BOTH THE NAM AND GFS INDICATE THAT THE ATMOSPHERE WILL DESTABILIZE BY AFTERNOON WITH CAPES MOST LIKELY INCREASING TO BETWEEN 1000 AND 1500 J/KG PER GFS AND ECM. ALSO...0-6KM SHEAR INCREASES TO ABOUT 40KT. THIS MAY SUPPORT SOME ORGANIZATION TO THE CONVECTION AS THE COLD FRONT MOVES THROUGH. THE 12Z NAM MODEL REFLECTIVITY SUGGESTS THAT A BROKEN LINE OF CONVECTION WILL ACCOMPANY THE FRONT ACROSS THE AREA ON MONDAY WITH A FEW SEVERE STORMS POSSIBLE. WITH THE AREA SOLIDLY IN THE WARM SECTOR ON MONDAY...MAX TEMPS ARE EXPECTED TO BE ABOUT 5 DEGREES ABOVE CLIMO. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 245 PM FRIDAY...MONDAY NIGHT...SFC HIGH PRESSURE WILL BUILD OVER THE FORECAST AREA IN THE WAKE OF A PASSING COLD FRONT. 12Z GFS INDICATES THAT H85 TEMPERATURES WILL COOL BY 5 C FROM 0Z TO 12Z TUESDAY...A LITTLE LESS COOLING ON THE ECMWF. USING A BLEND OF GUIDANCE...I WILL FORECAST LOW TEMPERATURES FROM THE UPPER 40S WITHIN THE MTN VALLEYS TO MID 50S EAST. ON TUESDAY...BROAD HIGH PRESSURE WILL REMAIN ACROSS THE CWA. THE REGION SHOULD SEE MOSTLY SUNNY CONDITIONS WITH A LIGHT SOUTHWEST WIND. TEMPERATURES SHOULD RESPOND TO THE LATE APRIL SUN AND WEAK DOWNSLOPING...FORECAST TUES HIGHS SLIGHTLY ABOVE NORMAL. WEDNESDAY THROUGH FRIDAY...THE GFS AND ECMWF GENERALLY AGREE THAT A LARGE CLOSED MID LEVEL LOW WILL REMAIN ACROSS THE NORTHEAST AND EASTERN CANADA...AS A RIDGE LINGERS OVER THE SOUTHERN PLAINS. THE HEIGHTS ACROSS THE CWA WILL LIKELY REMAIN NW TO SE THROUGH THE PERIOD. THE MODELS ARE IN LESS AGREEMENT WITH THE PLACEMENT AND TIMING OF SFC FEATURES...PRIMARILY WEAK FRONTS AND PRESSURE CENTERS. I AM MORE CONFIDENT TIMING MID LEVEL FEATURES WITHIN THE NW FLOW ACROSS THE SOUTHERN APPALACHIANS...I WILL FAVOR THE ECMWF. OVERALL...I WILL KEEP CONDITIONS DRY ON WED...BUT MOISTURE WILL INCREASE THROUGH THE DAY. A SHORT SERIES OF MID LEVEL S/W ARE FORECAST TO RIPPLE ACROSS THE CWA THURSDAY THROUGH FRIDAY. TEMPERATURES SHOULD RANGE CLOSE TO NORMAL WITH AFTERNOON DEWPOINTS ONLY IN THE 40S. GIVEN THE TRACK OF THE MID LEVEL DISTURBANCES AND WEAK DIURNAL INSTABILITY...I WILL INDICATE ONLY SCHC POPS ACROSS THE MTNS ON THURSDAY. FORECAST SOUNDINGS SHOW GREATER INSTABILITY FRIDAY AFTERNOON...FROM THE MTNS TO THE PIEDMONT. THE COMBINATION OF THE PASSING DISTURBANCE AND INSTABILITY SHOULD SUPPORT SCT COVERAGE ACROSS THE MTNS AND ISO EAST. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AT KCLT...EXPECT -SHRA TO SLOWLY SPREAD TOWARD THE AIRPORT AS ANOTHER UPPER WAVE PUSHES ACROSS THE REGION. VFR CONDITIONS STILL HANGING ON IN THE MEANTIME...BUT ONCE THE DEEPER MOISTURE ARRIVES... CIGS SHOULD DROP TO MVFR IN THE NEXT COUPLE OF HOURS. AS WINDS DECOUPLE OVERNIGHT...VSBYS SHOULD DROP TO MVFR AND POTENTIALLY LOWER EITHER BRIEFLY OR IN ISOLATED LOCATIONS...WITH CIGS DROPPING TO IFR. SLOW IMPROVING TREND ON SATURDAY WITH MVFR CIGS THROUGH THE PERIOD...THOUGH KCLT MAY BEGIN TO SEE SOME SCATTERING TOWARD THE END OF THE PERIOD. SW WINDS TO START WITH WEDGE CONTINUING TO ERODE... AND WINDS SHIFTING NNE AND NE SATURDAY IN THE WAKE OF THE UPPER WAVE AS A SURFACE HIGH PRESSURE AXIS PUSHES EAST OVER THE OHIO RIVER VALLEY. ELSEWHERE...AT KGSP/KGMU/KAND EXPECT AN OVERALL SIMILAR TREND TO KCLT BUT WITH -SHRA IN AT TAF INITIALIZATION AND CIGS DROPPING A LITTLE FASTER OVERNIGHT. KAVL/KHKY WILL SEE FEWER RESTRICTIONS BEING A LITTLE FARTHER NORTH FROM THE DEEP MOISTURE...AND IT IS POSSIBLE THAT KHKY MAY KEEP VFR CIGS THROUGH THE NIGHT THOUGH HAVE CONTINUED MVFR TREND WITH THIS ISSUANCE. MVFR VSBYS STILL LIKELY WITH SURFACE WINDS DROPPING OFF. ANY -TSRA TOO ISOLATED TO INCLUDE IN THE TAF AT THIS TIME. OUTLOOK...DRIER WEATHER IS FAVORED SATURDAY AFTERNOON. DEEPER MOISTURE WILL RETURN ALONG A WARM FRONT SAT NIGHT THROUGH SUNDAY...WITH HEAVY RAINFALL AND WIDESPREAD RESTRICTIONS LIKELY ONCE AGAIN. THUNDERSTORMS WILL THEN BE POSSIBLE THROUGH MONDAY AS A COLD FRONT REACHES THE AREA FROM THE WEST. CONFIDENCE TABLE... 23-05Z 05-11Z 11-17Z 17-18Z KCLT MED 64% MED 62% MED 64% HIGH 80% KGSP MED 71% MED 69% LOW 46% HIGH 90% KAVL HIGH 93% MED 62% MED 60% HIGH 100% KHKY LOW 57% HIGH 100% MED 64% HIGH 100% KGMU MED 78% MED 69% MED 64% HIGH 90% KAND LOW 57% MED 69% MED 78% HIGH 80% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...CSH NEAR TERM...CDG/TDP SHORT TERM...LG LONG TERM...NED AVIATION...TDP
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
626 PM CDT FRI APR 17 2015 .AVIATION... LOW STRATUS WAS BREAKING UP NEAR KCDS EARLY THIS EVENING. HOWEVER...THERE IS A CHANCE AT VLIFR CIGS AND VISBYS WILL RETURN EARLY SATURDAY MORNING WITH VERY MOIST LOW LEVEL AIR STILL IN PLACE. OTHERWISE...WINDS WILL COME AROUND TO THE WEST AT ALL TAF SITES TOMORROW AFTERNOON AND BECOME BREEZY. && .PREV DISCUSSION... /ISSUED 321 PM CDT FRI APR 17 2015/ SHORT TERM... DRYLINE AT 19Z EXTENDED FROM JUST WEST OF SILVERTON SOUTH TO WHITE RIVER LAKE AND NEAR LAKE ALAN HENRY. THIS BOUNDARY HAS BEEN FORCED WEST ALL DAY BY CONVECTIVE OUTFLOWS FARTHER EAST AND RECENT RUNS OF THE RUC HAVE THE DRYLINE ARRIVING ALONG INTERSTATE 27 BY THIS EVENING...PERHAPS MUCH SOONER. INSTABILITY-WISE...A NARROW AXIS OF SBCAPE AROUND 1000 J/KG MAY FULFILL SOME TSTORMS ALONG AND EAST OF THE DRYLINE THROUGH THE EVENING...BUT VISUAL TRENDS OF TOWERING AND MODERATE CU SUGGEST DEEPER ASCENT IS LACKING. WATER VAPOR IMAGERY INDICATE THIS AREA IS BATTLING SUBSIDENCE ALOFT DUE TO AN AXIS OF PERSISTENT DEEP CONVECTION 60-100 MILES FARTHER EAST. BECAUSE OF THIS AND LIMITED NWP SUPPORT...POPS HAVE BEEN SCALED BACK TO SLIGHT CHANCE FOR MOST AREAS OFF THE CAPROCK. AS THE FOUR CORNERS LOW BEGINS LIFTING NORTHEAST TONIGHT...LOWER TROPOSPHERIC WINDS WILL VEER MORE WESTERLY ACROSS THE WESTERN HALF OF THE CWA AND HELP TO NUDGE THE DRYLINE EASTWARD BEFORE DAYBREAK SAT. MODELS AGREE THE DRYLINE WILL MIX OUT OF OUR EASTERN ZONES BY MIDDAY AHEAD OF BREEZY SW WINDS...BUT ANY DISRUPTION TO THIS SUCH AS WE SAW TODAY WITH CONVECTIVE OUTFLOWS COULD SUPPORT A MORE WESTERLY DRYLINE LOCATION AND NECESSITATE MODIFICATIONS TO OUR DRY FORECAST FOR SATURDAY. WHEREVER THE DRYLINE ENDS UP...DEEP CONVECTION SHOULD EASILY UNFOLD BY SAT AFTN UNDER WEAK INHIBITION...STRONGER CYCLONIC FLOW AND A FAVORABLE MID-LEVEL COLD POCKET OF -20C AT 500MB. LONG TERM... COLD FRONT PROGGED TO MOVE THROUGH THE FCST AREA SUNDAY MORNING WITH ENOUGH COLD ADVECTION TO RESULT IN HIGHS MAINLY UPPER 60S AND LOWER 70S WHILE ALSO SCOURING LOW LEVEL MOISTURE OUT OF THE FCST AREA. MAY SEE SOME CONVECTION ATTEMPT TO DEVELOP ON THE HIGH TERRAIN OF NRN NM/SRN COLO AND BE DRIVEN TO THE SE ON NWLY UPPER FLOW...BUT WITH DRY LOW LEVELS WOULD EXPECT IT TO HAVE A HARD TIME GETTING THIS FAR TO THE SE. SITUATION CHANGES SOME MONDAY WHEN SOUTH AND SE WINDS BEGIN TO BRING MOISTURE BACK INTO THE AREA. LOOKS LIKE HIGH TERRAIN CONVECTION WILL HAVE A BETTER CHANCE OF MOVING THROUGH THE PANHANDLE AND INTO NRN PARTS OF THE FCST AREA. THE MIDDLE PART OF THE WEEK WILL THEN BE ONE WITH POSSIBILITY OF WEAKLY-FORCED DIURNAL DRYLINE STORMS WITH LOW LEVEL MOISTURE INCREASING WITH TIME...CONFLUENT FLOW ALOFT TRANSITIONING TO WEAK UPPER RIDGING. 20-30 PCT STORM CHANCES TUESDAY THROUGH FRIDAY LOOK FINE WITH THIS SYNOPTIC SETUP. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 40 70 40 65 / 0 0 10 0 TULIA 43 73 44 67 / 0 0 10 0 PLAINVIEW 44 73 45 68 / 0 0 0 0 LEVELLAND 43 75 46 70 / 0 0 0 0 LUBBOCK 45 76 47 71 / 0 0 0 0 DENVER CITY 44 74 47 71 / 0 0 0 0 BROWNFIELD 45 76 48 72 / 0 0 0 0 CHILDRESS 55 79 51 73 / 20 10 10 0 SPUR 53 79 50 73 / 20 0 0 0 ASPERMONT 56 81 52 77 / 20 10 10 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1012 PM EDT FRI APR 17 2015 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT AND SATURDAY BRINGING DRY AND WARM WEATHER FOR THE START OF THE WEEKEND. A COMPLEX STORM SYSTEM PASSING TO THE WEST WILL RESULT IN MORE WIDESPREAD RAIN 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 SATURDAY/... AS OF 1012 PM EDT FRIDAY... ISOLD SHOWERS HAVE DISSIPATED AND SEE NO REASON FOR ANY NEW ONES TO FIRE UP OVERNIGHT...OTHER THAN ONE OR TWO ACROSS NORTHERN NC GIVEN MUCAPE VALUES STILL AROUND 300-500 J/KG. ALSO KEEPING AN EYE ON THE NORTHERN EDGE OF AREA OF SHOWERS INTO SW NC...WHICH IS AHEAD OF A SHORT WAVE NEAR CHATTANOOGA...AS SOMETHING COULD SNEAK INTO OUR NW NC MTNS AFTER MIDNIGHT...BUT MOST GUIDANCE AGREES THIS WILL STAY JUST TO OUR SOUTH. LEFT SLIGHT CHC POP ACROSS SOUTHERN EDGE OF FCST AREA THROUGH MUCH OF THE NIGHT...BUT REMOVED MENTION EVERYWHERE ELSE. TRENDS LOOK BETTER FOR MORE CLEARING FROM WEST LATE...AND THUS POSSIBILITY OF SOME PATCHY VALLEY FOG WITH WET GROUND SO ADDED THAT AS WELL...MAINLY TO MTN VALLEYS. OVERNIGHT TEMPS LOOK ON TRACK AT THIS POINT. PREV DISC AS OF 635 PM EDT FRIDAY... UPDATE TO REFLECT CURRENT MAINLY ISOLD COVERAGE OF SHOWERS FROM FOOTHILLS INTO SOUTHSIDE VA. INCLUDED A COUPLE HOURS OF CHC POPS ACROSS SOUTHSIDE THROUGH EARLY EVENING WITH CLUSTER OF SHOWERS THERE...AND SO FAR NOT SEEING ANY SIGNS OF EVEN INTERCLOUD LIGHTNING WITH CELLS NEAR MTV AND DAN...BUT KEEPING ISOLD THUNDER IN FCST GIVEN SBCAPES OF 500-800 J/KG....AND SOME ISOL LTG IN CELLS JUST NORTHEAST OF BUCKINGHAM COUNTY. ALL THIS ACTIVITY SHOULD SLOWLY DIMINISH AS IT DRIFTS SOUTHEASTWARD INTO FAR NORTHERN NC BY 8 OR 9PM...AND RECENT HRRR RUNS SEEM TO BE DOING A BETTER JOB CAPTURING THE SPARSITY OF THE SHALLOW CONVECTION AND WEAKENING INTO THE EVENING HOURS WITH LOSS OF HEATING. SOME OF THE MORE WIDESPREAD LIGHT RAIN OVER FAR SW NC AND UPSTATE SC WILL SLIDE TO THE NORTHEAST IN ADVANCE OF WEAK SHORT WAVE HEADING EAST OUT OF TN...BUT PREVIOUS THINKING THAT IT WILL REMAIN SOUTH OF THE FCST AREA STILL LOOKS ON TRACK. WE DO KEEP A LINGERING SLIGHT CHC POP ACROSS NW NC MTNS UNTIL A LITTLE AFTER MIDNIGHT JUST IN CASE...BUT THEN DROP ALL POPS TOWARD MORNING. PREVIOUS DISCUSSION AS OF 235 PM EDT MONDAY... AT 18Z...A WEAK SURFACE TROF WAS NOTED JUST EAST OF THE BLUE RIDGE...AND WEAK CONVERGENCE ALONG THIS BOUNDARY COMBINED WITH SOME MODEST INSTABILITY (DCAPES 500-700 J/KG) SHOULD GENERATE ISOLATED SHOWERS AND STORMS ALONG THE BLUE RIDGE AS WELL AS AREAS NORTH OF I- 64 WHERE VISIBLE SATELLITE SHOWS SOME ENHANCED CUMULUS FORMING IN ADVANCE OF A FAINT UPPER LEVEL DISTURBANCE. MESOSCALE MODELS ARE OVERDONE ON THIS COVERAGE OF THIS PRECIP...BUT GENERALLY HAVE A GOOD HANDLE ON THE LOCATION OF DEVELOPMENT. ANY ISOLATED/WIDELY SCATTERED PRECIP THAT DEVELOPS SHOULD GRADUALLY DIMINISH TONIGHT...BEFORE AN UPPER LEVEL SHORTWAVE IN WEST TENNESSEE ZIPS ACROSS NRN NC LATE TONIGHT. THIS SYSTEM WILL BRING AN INCREASE IN CLOUD COVER...ESPECIALLY ACROSS THE SOUTHERN PORTION OF OUR FORECAST AREA LATE TONIGHT...AND A FEW SHOWERS MAY BE POSSIBLE. AT THE SFC...HIGH PRESSURE WILL SLOWLY NOSE SOUTH INTO THE EASTERN OHIO VALLEY BRINGING A LIGHT NORTH WIND. A SHALLOW LAYER OF MOISTURE NEAR THE SURFACE WILL REMAIN...WHICH WILL RESULT IN POCKETS OF FOG...ESPECIALLY WHERE CLOUDS ARE ABSENT TO THE NORTH. LEANED TOWARD THE WARMER GUIDANCE VALUES WITH CLOUDS. FOR SATURDAY...HEIGHTS BUILD IN ADVANCE OF A DEEP UPPER LEVEL TROF IN THE WEST AND TEMPS SHOULD AGAIN WARM WELL INTO THE 70S AND THE 80S IN THE EAST. A WEAK LOW LEVEL EAST FLOW COMBINED WITH A NOSE OF HIGHER THETA-E AIR IN NW NC INTO FAR SW VA MAY SPARK ISOLATED SHOWERS/STORMS. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... AS OF 330 PM EDT FRIDAY... FOCUS THROUGH THIS PERIOD REMAINS ON A STRONG NEGATIVELY TILTED UPPER TROUGH PROGGED TO LIFT RAPIDLY NORTHEAST ACROSS THE REGION SUNDAY INTO EARLY MONDAY. MEANWHILE...ANTECEDENT HIGH PRESSURE WILL MOVE OFF THE MID-ATLANTIC COAST INTO A NEAR CLASSIC WEDGE POSITION. STRONG PVA/ISENTROPIC LIFT INDUCED RAINFALL INTO THE WEDGE AIR MASS WILL ENHANCE/INTENSIFY THE WEDGE SUNDAY. RAINFALL/QPF WILL BE THE MAIN CONCERN AS THE WEDGE KEEPS A VERY STABLE/COOL AIR MASS IS PLACE. MOIST SOUTHEAST...UPSLOPE FLOW ALONG THE BLUE RIDGE WILL ENHANCE RAINFALL...ESPECIALLY ACROSS WATAUGA NORTHEAST TOWARD FLOYD. AS NOTED YESTERDAY...HOWEVER...THE SYSTEM WILL REMAIN HIGHLY PROGRESSIVE...LIMITING THE PERIOD OF HEAVIER RAINFALL TO 12 HOURS OR LESS. WPC HAS PARTS OF THE NC/VA SOUTHERN VA PIEDMONT OUTLOOKED FOR EXCESSIVE RAINFALL. THE MAIN CONCERN WITHIN THIS AREA WOULD BE WATAUGA THROUGH ASHE/WILKES...WITH LESS CONCERN TOWARD THE DANVILLE AREA WHERE ANTECEDENT CONDITIONS ARE RELATIVELY DRY. IN ADDITION...THE CONVECTIVE THREAT THROUGH THE HEAVIER RAIN PERIOD AS NOTED ABOVE IS MINIMAL TO NONE...WHICH SHOULD FURTHER REDUCE THE FLASH FLOOD THREAT. WILL RE-EVALUATE AGAIN TOMORROW...BUT AT THIS POINT NO NEED FOR A FLOOD/FLASH FLOOD WATCH. ONE MAY EVENTUALLY BE NEEDED FOR A SMALL AREA INCLUDING THE NW NC MOUNTAINS AND THE ADJACENT FOOTHILLS. WENT WELL BELOW GUIDANCE ON MAX TEMPS IN THE WEDGE SUNDAY...BUT AT OR ABOVE GUIDANCE ON MONDAY IN THE WARM SECTOR. MAX TEMPS MONDAY WILL BE A GOOD 20 DEGREES WARMER IN MOST AREAS THAN ON SUNDAY. MONDAY IS A DIFFERENT STORY. A SIGNIFICANT WARM SECTOR WILL SURGE NORTHWARD INTO THE REGION MONDAY AFTERNOON BEHIND THE DEPARTING UPPER TROUGH AND AN APPROACHING STRONG COLD FRONT ASSOCIATED WITH A DEEPENING BROAD UPPER TROUGH ACROSS THE GREAT LAKES. SEVERAL OF THE MODELS CONTINUE TO ADVERTISE GOOD POTENTIAL FOR STRONG THUNDERSTORMS MONDAY AFTERNOON...WITH SIGNIFICANT SVR PARAMETER NEAR 20000 ACROSS THE PIEDMONT...CAPES NEARING 2000 J/KG WITH AT LEAST 20-30KTS OF 0-2KM LOW-LEVEL SHEAR AND LIS NEAR -4C. SPC DAY 4 OUTLOOK SUGGESTS THAT DAMAGING WINDS WOULD BE THE MAIN CONCERN WITH ANY CONVECTION...MOST LIKELY LINEAR ORIENTED...THAT DEVELOPS ALONG/IN ADVANCE OF THE COLD FRONT MONDAY AFTERNOON/EVENING. THIS ACTIVITY QUICKLY MOVES EAST OF THE REGION MON AFTERNOON. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 345 PM EDT FRIDAY... A TRANSITION TO A PATTERN MORE REMINISCENT OF WINTER CONTINUES TO BE IN THE CARDS FOR THE EARLY AND MID PART OF NEXT WEEK AS A DEEP AND BROAD UPPER TROUGH BUILDS INTO THE CENTRAL/EASTERN U.S. BY TUESDAY...500MB HEIGHTS DROP INTO THE 560DM RANGE AND 850MB TEMPS PLUNGE TOWARD THE 0C MARK ACROSS THE NORTH BY MIDWEEK. ANTICYCLONIC FLOW...A SERIES OF EMBEDDED UPPER DISTURBANCES...AND COLD ADVECTION WILL KEEP VARIABLE CLOUDINESS AND POTENTIALLY UPSLOPE SHOWERS IN PLACE ACROSS THE MOUNTAINS. THE CLOUDS AND CYCLONIC FLOW WILL HOLD MAX TEMPS INTO THE 50S AND LOWER 60S ACROSS THE MOUNTAINS THROUGH MUCH OF THE LATER HALF OF NEXT WEEK...WHILE 60S TO 70S PREVAIL TO THE EAST WITH DOWNSLOPE NORTHWEST FLOW AND SIGNIFICANTLY GREATER AMOUNTS OF SUNSHINE. AT THIS POINT A DISTURBANCE ON WED APPEARS TO BE THE MOST SIGNIFICANT IN POTENTIALLY BRINGING SHOWERS EAST OF THE MOUNTAINS. HAVE NOT INTRODUCED ANY THUNDER AT THIS POINT GIVEN THE LOW-LEVEL COLD/STABLE AIR MASS. BY MID-WEEK...THE GFS/ECMWF BEGIN TO DIVERGE ON THE OVERALL PATTERN...WITH THE ECMWF KEEPING THE DEEP UPPER TROUGH IN PLACE ACROSS THE NORTHEAST AND A STRONGER NW FLOW INTO OUR REGION AS WELL...WHILE THE GFS DEPICTS THE UPPER TROUGH LIFTING FURTHER NORTH AND PLACING A ZONAL FLOW WITH A BAROCLINIC ZONE STUCK ACROSS OUR CWA. THIS RESULTS IN SIGNIFICANT DIFFERENCES BETWEEN MOISTURE/POPS ACROSS OUR CWA BETWEEN THE TWO MODELS...WITH THE GFS VERY WET AND THE ECMWF MUCH DRIER...KEEPING THE BAROCLINIC ZONE MUCH FURTHER SOUTH. HAVE JUST ADVERTISED CHC POPS FOR NOW UNTIL A BETTER HANDLE ON THIS PATTERN AND TIMING IS OBTAINED. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL THROUGH THE MID PART OF THE WEEK...GRADUALLY TRENDING CLOSER TO NORMAL BY THE END OF THE PERIOD. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... AS OF 750 PM EDT FRIDAY... ISOLD SHOWERS NOT EXPECTED TO IMPACT ANY AIRPORTS THIS EVENING...AND FOR MOST OF THE OVERNIGHT EXPECTING VFR CONDITIONS AND LIGHT TO CALM WINDS WITH HIGH PRESSURE IN CONTROL. SOME MOISTURE OFF TO SOUTH SHOULD REMAIN THERE WITH WEAK SHORT WAVE MOVING IN FROM THE WEST ACROSS TENNESSEE AND SHUNTING AN AREA OF SHOWERS EASTWARD. THIS WAVE WILL ALSO EVENTUALLY TAKE MID TO HIGH CLOUDS EAST AND WITH CLEARING THERE IS LIKELY TO BE SOME RADIATION FOG FORMING...LOWERED CONDITIONS TO IFR AT BLF...LWB...BCB...AND LYH BY 08-09Z...BUT MOST CONFIDENT IN IFR CONDITIONS AT LWB AND BCB. ANY FOG AND LOW STRATUS DISSIPATES BY 13Z OR SO...FOR WIDESPREAD VFR CONDITIONS FOR THE DAY SATURDAY...WITH LIGHT EAST TO NORTHEAST WINDS AS SFC HIGH PRESSURE REMAINS TO THE NORTH AND WEAK SFC TROUGH WILL LINGER ACROSS NORTH CAROLINA. THIS MAY RESULT IN ENOUGH WEAK CONVERGENCE AND UPSLOPE TO KICK OFF A FEW ISOLD SHWRS OR TSTORMS BY AFTERNOON...ESPECIALLY NEAR BLUE RIDGE ALONG OR SOUTH OF VA/NC BORDER...BUT VERY UNLIKELY ANY ONE SHOWER OR STORM WILL IMPACT ANY AIRPORTS. EXTENDED AVIATION... A COMPLEX STORM SYSTEM WILL BEGIN TO AFFECT THE REGION LATER IN THE WEEKEND WITH A WARM FRONT BRINGING WIDESPREAD MVFR/IFR CONDITIONS IN RAIN DURING THE DAY SUNDAY INTO SUNDAY NIGHT... FOLLOWED BY ANOTHER COLD FRONTAL PASSAGE MONDAY. THIS LIKELY TO KEEP PERIODS OF MVFR IN PLACE UNTIL THE FRONT POSSIBLY CLEARS THE REGION LATER MONDAY. VFR RETURNS LATER MONDAY NIGHT AND TUESDAY WITH HIGH PRESSURE BUILDING IN BEHIND THE FRONT WITH GOOD DRYING EXPECTED. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PH NEAR TERM...JH/PH/SK SHORT TERM...RAB LONG TERM...RAB AVIATION...JH/PH/SK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
753 PM EDT FRI APR 17 2015 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT AND SATURDAY BRINGING DRY AND WARM WEATHER FOR THE START OF THE WEEKEND. A COMPLEX STORM SYSTEM PASSING TO THE WEST WILL RESULT IN MORE WIDESPREAD RAIN 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 SATURDAY/... AS OF 635 PM EDT FRIDAY... UPDATE TO REFLECT CURRENT MAINLY ISOLD COVERAGE OF SHOWERS FROM FOOTHILLS INTO SOUTHSIDE VA. INCLUDED A COUPLE HOURS OF CHC POPS ACROSS SOUTHSIDE THROUGH EARLY EVENING WITH CLUSTER OF SHOWERS THERE...AND SO FAR NOT SEEING ANY SIGNS OF EVEN INTERCLOUD LIGHTNING WITH CELLS NEAR MTV AND DAN...BUT KEEPING ISOLD THUNDER IN FCST GIVEN SBCAPES OF 500-800 J/KG....AND SOME ISOL LTG IN CELLS JUST NORTHEAST OF BUCKINGHAM COUNTY. ALL THIS ACTIVITY SHOULD SLOWLY DIMINISH AS IT DRIFTS SOUTHEASTWARD INTO FAR NORTHERN NC BY 8 OR 9PM...AND RECENT HRRR RUNS SEEM TO BE DOING A BETTER JOB CAPTURING THE SPARSITY OF THE SHALLOW CONVECTION AND WEAKENING INTO THE EVENING HOURS WITH LOSS OF HEATING. SOME OF THE MORE WIDESPREAD LIGHT RAIN OVER FAR SW NC AND UPSTATE SC WILL SLIDE TO THE NORTHEAST IN ADVANCE OF WEAK SHORT WAVE HEADING EAST OUT OF TN...BUT PREVIOUS THINKING THAT IT WILL REMAIN SOUTH OF THE FCST AREA STILL LOOKS ON TRACK. WE DO KEEP A LINGERING SLIGHT CHC POP ACROSS NW NC MTNS UNTIL A LITTLE AFTER MIDNIGHT JUST IN CASE...BUT THEN DROP ALL POPS TOWARD MORNING. PREVIOUS DISCUSSION AS OF 235 PM EDT MONDAY... AT 18Z...A WEAK SURFACE TROF WAS NOTED JUST EAST OF THE BLUE RIDGE...AND WEAK CONVERGENCE ALONG THIS BOUNDARY COMBINED WITH SOME MODEST INSTABILITY (DCAPES 500-700 J/KG) SHOULD GENERATE ISOLATED SHOWERS AND STORMS ALONG THE BLUE RIDGE AS WELL AS AREAS NORTH OF I- 64 WHERE VISIBLE SATELLITE SHOWS SOME ENHANCED CUMULUS FORMING IN ADVANCE OF A FAINT UPPER LEVEL DISTURBANCE. MESOSCALE MODELS ARE OVERDONE ON THIS COVERAGE OF THIS PRECIP...BUT GENERALLY HAVE A GOOD HANDLE ON THE LOCATION OF DEVELOPMENT. ANY ISOLATED/WIDELY SCATTERED PRECIP THAT DEVELOPS SHOULD GRADUALLY DIMINISH TONIGHT...BEFORE AN UPPER LEVEL SHORTWAVE IN WEST TENNESSEE ZIPS ACROSS NRN NC LATE TONIGHT. THIS SYSTEM WILL BRING AN INCREASE IN CLOUD COVER...ESPECIALLY ACROSS THE SOUTHERN PORTION OF OUR FORECAST AREA LATE TONIGHT...AND A FEW SHOWERS MAY BE POSSIBLE. AT THE SFC...HIGH PRESSURE WILL SLOWLY NOSE SOUTH INTO THE EASTERN OHIO VALLEY BRINGING A LIGHT NORTH WIND. A SHALLOW LAYER OF MOISTURE NEAR THE SURFACE WILL REMAIN...WHICH WILL RESULT IN POCKETS OF FOG...ESPECIALLY WHERE CLOUDS ARE ABSENT TO THE NORTH. LEANED TOWARD THE WARMER GUIDANCE VALUES WITH CLOUDS. FOR SATURDAY...HEIGHTS BUILD IN ADVANCE OF A DEEP UPPER LEVEL TROF IN THE WEST AND TEMPS SHOULD AGAIN WARM WELL INTO THE 70S AND THE 80S IN THE EAST. A WEAK LOW LEVEL EAST FLOW COMBINED WITH A NOSE OF HIGHER THETA-E AIR IN NW NC INTO FAR SW VA MAY SPARK ISOLATED SHOWERS/STORMS. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... AS OF 330 PM EDT FRIDAY... FOCUS THROUGH THIS PERIOD REMAINS ON A STRONG NEGATIVELY TILTED UPPER TROUGH PROGGED TO LIFT RAPIDLY NORTHEAST ACROSS THE REGION SUNDAY INTO EARLY MONDAY. MEANWHILE...ANTECEDENT HIGH PRESSURE WILL MOVE OFF THE MID-ATLANTIC COAST INTO A NEAR CLASSIC WEDGE POSITION. STRONG PVA/ISENTROPIC LIFT INDUCED RAINFALL INTO THE WEDGE AIR MASS WILL ENHANCE/INTENSIFY THE WEDGE SUNDAY. RAINFALL/QPF WILL BE THE MAIN CONCERN AS THE WEDGE KEEPS A VERY STABLE/COOL AIR MASS IS PLACE. MOIST SOUTHEAST...UPSLOPE FLOW ALONG THE BLUE RIDGE WILL ENHANCE RAINFALL...ESPECIALLY ACROSS WATAUGA NORTHEAST TOWARD FLOYD. AS NOTED YESTERDAY...HOWEVER...THE SYSTEM WILL REMAIN HIGHLY PROGRESSIVE...LIMITING THE PERIOD OF HEAVIER RAINFALL TO 12 HOURS OR LESS. WPC HAS PARTS OF THE NC/VA SOUTHERN VA PIEDMONT OUTLOOKED FOR EXCESSIVE RAINFALL. THE MAIN CONCERN WITHIN THIS AREA WOULD BE WATAUGA THROUGH ASHE/WILKES...WITH LESS CONCERN TOWARD THE DANVILLE AREA WHERE ANTECEDENT CONDITIONS ARE RELATIVELY DRY. IN ADDITION...THE CONVECTIVE THREAT THROUGH THE HEAVIER RAIN PERIOD AS NOTED ABOVE IS MINIMAL TO NONE...WHICH SHOULD FURTHER REDUCE THE FLASH FLOOD THREAT. WILL RE-EVALUATE AGAIN TOMORROW...BUT AT THIS POINT NO NEED FOR A FLOOD/FLASH FLOOD WATCH. ONE MAY EVENTUALLY BE NEEDED FOR A SMALL AREA INCLUDING THE NW NC MOUNTAINS AND THE ADJACENT FOOTHILLS. WENT WELL BELOW GUIDANCE ON MAX TEMPS IN THE WEDGE SUNDAY...BUT AT OR ABOVE GUIDANCE ON MONDAY IN THE WARM SECTOR. MAX TEMPS MONDAY WILL BE A GOOD 20 DEGREES WARMER IN MOST AREAS THAN ON SUNDAY. MONDAY IS A DIFFERENT STORY. A SIGNIFICANT WARM SECTOR WILL SURGE NORTHWARD INTO THE REGION MONDAY AFTERNOON BEHIND THE DEPARTING UPPER TROUGH AND AN APPROACHING STRONG COLD FRONT ASSOCIATED WITH A DEEPENING BROAD UPPER TROUGH ACROSS THE GREAT LAKES. SEVERAL OF THE MODELS CONTINUE TO ADVERTISE GOOD POTENTIAL FOR STRONG THUNDERSTORMS MONDAY AFTERNOON...WITH SIGNIFICANT SVR PARAMETER NEAR 20000 ACROSS THE PIEDMONT...CAPES NEARING 2000 J/KG WITH AT LEAST 20-30KTS OF 0-2KM LOW-LEVEL SHEAR AND LIS NEAR -4C. SPC DAY 4 OUTLOOK SUGGESTS THAT DAMAGING WINDS WOULD BE THE MAIN CONCERN WITH ANY CONVECTION...MOST LIKELY LINEAR ORIENTED...THAT DEVELOPS ALONG/IN ADVANCE OF THE COLD FRONT MONDAY AFTERNOON/EVENING. THIS ACTIVITY QUICKLY MOVES EAST OF THE REGION MON AFTERNOON. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 345 PM EDT FRIDAY... A TRANSITION TO A PATTERN MORE REMINISCENT OF WINTER CONTINUES TO BE IN THE CARDS FOR THE EARLY AND MID PART OF NEXT WEEK AS A DEEP AND BROAD UPPER TROUGH BUILDS INTO THE CENTRAL/EASTERN U.S. BY TUESDAY...500MB HEIGHTS DROP INTO THE 560DM RANGE AND 850MB TEMPS PLUNGE TOWARD THE 0C MARK ACROSS THE NORTH BY MIDWEEK. ANTICYCLONIC FLOW...A SERIES OF EMBEDDED UPPER DISTURBANCES...AND COLD ADVECTION WILL KEEP VARIABLE CLOUDINESS AND POTENTIALLY UPSLOPE SHOWERS IN PLACE ACROSS THE MOUNTAINS. THE CLOUDS AND CYCLONIC FLOW WILL HOLD MAX TEMPS INTO THE 50S AND LOWER 60S ACROSS THE MOUNTAINS THROUGH MUCH OF THE LATER HALF OF NEXT WEEK...WHILE 60S TO 70S PREVAIL TO THE EAST WITH DOWNSLOPE NORTHWEST FLOW AND SIGNIFICANTLY GREATER AMOUNTS OF SUNSHINE. AT THIS POINT A DISTURBANCE ON WED APPEARS TO BE THE MOST SIGNIFICANT IN POTENTIALLY BRINGING SHOWERS EAST OF THE MOUNTAINS. HAVE NOT INTRODUCED ANY THUNDER AT THIS POINT GIVEN THE LOW-LEVEL COLD/STABLE AIR MASS. BY MID-WEEK...THE GFS/ECMWF BEGIN TO DIVERGE ON THE OVERALL PATTERN...WITH THE ECMWF KEEPING THE DEEP UPPER TROUGH IN PLACE ACROSS THE NORTHEAST AND A STRONGER NW FLOW INTO OUR REGION AS WELL...WHILE THE GFS DEPICTS THE UPPER TROUGH LIFTING FURTHER NORTH AND PLACING A ZONAL FLOW WITH A BAROCLINIC ZONE STUCK ACROSS OUR CWA. THIS RESULTS IN SIGNIFICANT DIFFERENCES BETWEEN MOISTURE/POPS ACROSS OUR CWA BETWEEN THE TWO MODELS...WITH THE GFS VERY WET AND THE ECMWF MUCH DRIER...KEEPING THE BAROCLINIC ZONE MUCH FURTHER SOUTH. HAVE JUST ADVERTISED CHC POPS FOR NOW UNTIL A BETTER HANDLE ON THIS PATTERN AND TIMING IS OBTAINED. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL THROUGH THE MID PART OF THE WEEK...GRADUALLY TRENDING CLOSER TO NORMAL BY THE END OF THE PERIOD. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 750 PM EDT FRIDAY... ISOLD SHOWERS NOT EXPECTED TO IMPACT ANY AIRPORTS THIS EVENING...AND FOR MOST OF THE OVERNIGHT EXPECTING VFR CONDITIONS AND LIGHT TO CALM WINDS WITH HIGH PRESSURE IN CONTROL. SOME MOISTURE OFF TO SOUTH SHOULD REMAIN THERE WITH WEAK SHORT WAVE MOVING IN FROM THE WEST ACROSS TENNESSEE AND SHUNTING AN AREA OF SHOWERS EASTWARD. THIS WAVE WILL ALSO EVENTUALLY TAKE MID TO HIGH CLOUDS EAST AND WITH CLEARING THERE IS LIKELY TO BE SOME RADIATION FOG FORMING...LOWERED CONDITIONS TO IFR AT BLF...LWB...BCB...AND LYH BY 08-09Z...BUT MOST CONFIDENT IN IFR CONDITIONS AT LWB AND BCB. ANY FOG AND LOW STRATUS DISSIPATES BY 13Z OR SO...FOR WIDESPREAD VFR CONDITIONS FOR THE DAY SATURDAY...WITH LIGHT EAST TO NORTHEAST WINDS AS SFC HIGH PRESSURE REMAINS TO THE NORTH AND WEAK SFC TROUGH WILL LINGER ACROSS NORTH CAROLINA. THIS MAY RESULT IN ENOUGH WEAK CONVERGENCE AND UPSLOPE TO KICK OFF A FEW ISOLD SHWRS OR TSTORMS BY AFTERNOON...ESPECIALLY NEAR BLUE RIDGE ALONG OR SOUTH OF VA/NC BORDER...BUT VERY UNLIKELY ANY ONE SHOWER OR STORM WILL IMPACT ANY AIRPORTS. EXTENDED AVIATION... A COMPLEX STORM SYSTEM WILL BEGIN TO AFFECT THE REGION LATER IN THE WEEKEND WITH A WARM FRONT BRINGING WIDESPREAD MVFR/IFR CONDITIONS IN RAIN DURING THE DAY SUNDAY INTO SUNDAY NIGHT... FOLLOWED BY ANOTHER COLD FRONTAL PASSAGE MONDAY. THIS LIKELY TO KEEP PERIODS OF MVFR IN PLACE UNTIL THE FRONT POSSIBLY CLEARS THE REGION LATER MONDAY. VFR RETURNS LATER MONDAY NIGHT AND TUESDAY WITH HIGH PRESSURE BUILDING IN BEHIND THE FRONT WITH GOOD DRYING EXPECTED. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PH NEAR TERM...JH/PH/SK SHORT TERM...RAB LONG TERM...RAB AVIATION...JH/PH/SK
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML

AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1250 PM CDT THU APR 16 2015 UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE .SHORT TERM...TODAY...TONIGHT...AND FRIDAY ISSUED AT 257 AM CDT THU APR 16 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE CENTERED OVER THE EAST COAST...BUT WITH A RIDGE AXIS EXTENDING WEST TO THE WESTERN GREAT LAKES. VERY DRY AIR CONTINUES TO HOLD ON ACROSS THE REGION...AND DEWPOINTS HAVE STRUGGLED TO RECOVER OVER CENTRAL AND NORTH-CENTRAL WISCONSIN OVERNIGHT. SOUTHEAST LOW LEVEL FLOW OVER THE SOUTHERN GREAT LAKES IS SLOWLY VEERING TO MORE OF A SOUTHERLY DIRECTION...BUT IS STILL TRYING TO PUSH LIGHT SHOWER ACTIVITY ACROSS SOUTH-CENTRAL LAKE MICHIGAN. THIS IS AHEAD OF A SHORTWAVE OVER THE IL/IN BORDER. THE BONE DRY AIRMASS AND VEERING FLOW IS NOT HELPING THESE SHOWERS TO MAKE A WESTWARD JAUNT...AND THE LATEST MESOMODELS KEEP THESE SHOWERS EAST OF THE MANITOWOC SHORELINE EARLY THIS MORNING. THIS SHOWER ACTIVITY ALONG WITH FIRE WEATHER CONDITIONS ARE THE MAIN FORECAST CONCERNS IN THE SHORT TERM. TODAY...THE SHORTWAVE OVER THE IL/IN BORDER WILL LIFT NE THIS MORNING AND THEN EAST THIS AFTERNOON AS RIDGING OVER THE GREAT LAKES FLATTENS. 850MB FLOW WILL CONTINUE TO VERY GRADUALLY VEER THIS MORNING WHICH COMBINED WITH THE VERY DRY AIR ACROSS THE REGION WILL GIVE THE LIGHT SHOWER ACTIVITY OVER SOUTHERN LAKE MICHIGAN A SUBTLE PUSH TO THE EAST. SO WILL KEEP THE DRY FORECAST IN TACT...BUT WILL INCREASE CLOUD COVER OVER EAST-CENTRAL WISCONSIN TODAY AS 5K-6KFT CLOUDS OVER NORTHERN ILLINOIS WILL LIKELY ARRIVE THIS MORNING. ELSEWHERE...A MID-LEVEL DECK OVER MINNESOTA AND IOWA WILL SHIFT TO THE EAST AND MOVE INTO NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON. UNTIL THESE CLOUDS ARRIVE...A POCKET OF VERY DRY AIR WILL REMAIN IN PLACE ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN. MIXING WILL NOT BE AS GOOD TODAY DUE TO LIGHTER WINDS ALOFT...BUT STILL LOWERED DEWPOINTS SINCE THINK WILL STILL BE ABLE TO TAP INTO SOME OF THE BONE DRY AIR JUST ABOVE THE INVERSION. AS A RESULT...HAVE DROPPED DEWPOINTS AND HUMIDITIES OVER CENTRAL AND NORTH-CENTRAL WISCONSIN THIS AFTERNOON. HUMIDITIES COULD FALL BETWEEN 20-25 PCT. FORTUNATELY...WINDS WILL BE MUCH LIGHTER TODAY...SO SHOULD NOT SEE A REPEAT OF THE CRITICAL FIRE WEATHER CONDITIONS. HIGHS MAINLY IN THE MID TO UPPER 60S AWAY FROM LAKE MICHIGAN. TONIGHT...A COLD FRONT WILL DECAY AS IT MOVES INTO NORTH-CENTRAL WISCONSIN LATE. MID-LEVEL CLOUDS WILL CONTINUE TO SPREAD EAST AHEAD OF THE FRONT...BUT GRADUALLY DISSIPATE IN THE PROCESS. SHOULD THEREFORE SEE A PARTLY CLOUDY TO MOSTLY CLEAR NIGHT. WITH THE THINNING CLOUDS...DO NOT THINK THERE WILL BE A DEEP ENOUGH CLOUD LAYER FOR SPRINKLES OR LIGHT SHOWERS. LOWS MAINLY IN THE LOW TO MID 40S. FRIDAY...THE FRONT WILL WASH OUT ACROSS NORTHERN WISCONSIN. MAY SEE SOME CU DEVELOP OVER CENTRAL AND EAST-CENTRAL WISCONSIN DURING THE AFTERNOON...BUT THE NORTH SHOULD SEE AN INFLUX OF DRY AIR...THAT WILL DROP HUMIDITIES NEAR 25 PCT IN THE AFTERNOON. HIGHS WILL BE WARMER THAN TODAYS READINGS...AND RAISED THEM INTO THE UPPER 60S NORTH TO MID 70S SOUTH. .LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY ISSUED AT 257 AM CDT THU APR 16 2015 DRY CONDITIONS WILL CONTINUE FRIDAY NIGHT AND SATURDAY AS CANADIAN HIGH PRESSURE BUILDS INTO THE STATE. NORTHWEST WINDS WILL TURN TO THE EAST AND NORTHEAST LATE FRIDAY NIGHT AND SATURDAY. SATURDAY AFTERNOON WILL AGAIN FEATURE VERY LOW AFTERNOON RELATIVE HUMIDITY READINGS AWAY FROM THE LAKE...WITH READINGS DROPPING INTO THE 20 TO 40 PERCENT RANGE WITH THE LOWEST READINGS NORTH AND WEST OF THE FOX VALLEY. MEANWHILE...CLOSED UPPER LOW ACROSS THE CENTRAL PLAINS IS EXPECTED TO OPEN UP AS 500MB TROUGH ACROSS SOUTHERN CANADA WILL BEGIN TO LIFT THE SOUTHERN SYSTEM NORTHEAST TOWARDS THE REGION. QUIET A SPREAD IN THE MODELS ON HOW QUICK THE RAIN WILL ARRIVE OVER THE WEEKEND. THE WRF MODELS WAS QUICKEST...ALREADY BRINGING RAIN ON SATURDAY TO PORTIONS OF THE AREA. THE GFS MODEL WAS IN THE MIDDLE OF THE ROAD SOLUTION...WHILE THE CANADIAN/ECMWF MODEL WERE THE SLOWEST SOLUTION WITH RAIN ARRIVING ON SUNDAY. TRENDED TOWARD THE SLOWER SOLUTION FOR THE MEANTIME DUE TO BETTER CONSISTENCY FROM RUN TO RUN. DID ADD A SMALL CHANCE OF RAIN ACROSS THE WEST LATE SATURDAY NIGHT...AND THEN BOOSTED RAIN CHANCES INTO THE LIKELY CATEGORY ON SUNDAY. DID RAISE RAIN CHANCES SUNDAY NIGHT AS WELL. THE 500MB SYSTEMS WILL MERGE INTO A CLOSED UPPER LOW ACROSS THE UPPER MIDWEST AND WESTERN GREAT LAKES REGION EARLY NEXT WEEK. THIS WOULD SUPPORT A COOLER AND UNSETTLED PATTERN ACROSS THE REGION ON MONDAY THROUGH WEDNESDAY. HAVE CHANCES OF SHOWERS EACH PERIOD... ALONG WITH A LITTLE SNOW LATE AT NIGHT INTO THE EARLY MORNING HOURS ON TUESDAY AND WEDNESDAY. IT IS WISCONSIN! TEMPERATURES BY EARLY NEXT WEEK WILL RUN WELL BELOW NORMAL. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1250 PM CDT THU APR 16 2015 VFR CONDITIONS SHOULD PREVAIL THROUGH AT LEAST FRIDAY MORNING. A CLOUD DECK BELOW 1KFT MOVED INTO THE SOUTHEAST PART OF THE AREA THIS MORNING BUT MOVED OVER LAKE MICHIGAN BY 17Z. RADAR SHOWED SOME ECHOES ACROSS PARTS OF CENTRAL/NORTH CENTRAL WISCONSIN DRIFTING TO THE EAST BUT THEY WERE SCATTERED...SURFACE DEW POINT DEPRESSIONS WERE IN EXCESS OF 30F...AND MOST OF THE SURFACE OBSERVATIONS IN THAT PART OF THE STATE DID NOT EVEN INDICATE ANY CLOUDS. MODEL TIME SECTIONS SHOWED A MOIST LAYER OVERNIGHT IN THE 5KFT-10KFT RANGE...WITH DECREASING RH IN THAT LAYER AROUND 12Z. THE SURFACE PRESSURE GRADIENT IS NOT EXPECTED TO BE TIGHT...SO WINDS SHOULD REMAIN LIGHT. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......MG
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
606 AM CDT THU APR 16 2015 UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE .SHORT TERM...TODAY...TONIGHT...AND FRIDAY ISSUED AT 257 AM CDT THU APR 16 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE CENTERED OVER THE EAST COAST...BUT WITH A RIDGE AXIS EXTENDING WEST TO THE WESTERN GREAT LAKES. VERY DRY AIR CONTINUES TO HOLD ON ACROSS THE REGION...AND DEWPOINTS HAVE STRUGGLED TO RECOVER OVER CENTRAL AND NORTH-CENTRAL WISCONSIN OVERNIGHT. SOUTHEAST LOW LEVEL FLOW OVER THE SOUTHERN GREAT LAKES IS SLOWLY VEERING TO MORE OF A SOUTHERLY DIRECTION...BUT IS STILL TRYING TO PUSH LIGHT SHOWER ACTIVITY ACROSS SOUTH-CENTRAL LAKE MICHIGAN. THIS IS AHEAD OF A SHORTWAVE OVER THE IL/IN BORDER. THE BONE DRY AIRMASS AND VEERING FLOW IS NOT HELPING THESE SHOWERS TO MAKE A WESTWARD JAUNT...AND THE LATEST MESOMODELS KEEP THESE SHOWERS EAST OF THE MANITOWOC SHORELINE EARLY THIS MORNING. THIS SHOWER ACTIVITY ALONG WITH FIRE WEATHER CONDITIONS ARE THE MAIN FORECAST CONCERNS IN THE SHORT TERM. TODAY...THE SHORTWAVE OVER THE IL/IN BORDER WILL LIFT NE THIS MORNING AND THEN EAST THIS AFTERNOON AS RIDGING OVER THE GREAT LAKES FLATTENS. 850MB FLOW WILL CONTINUE TO VERY GRADUALLY VEER THIS MORNING WHICH COMBINED WITH THE VERY DRY AIR ACROSS THE REGION WILL GIVE THE LIGHT SHOWER ACTIVITY OVER SOUTHERN LAKE MICHIGAN A SUBTLE PUSH TO THE EAST. SO WILL KEEP THE DRY FORECAST IN TACT...BUT WILL INCREASE CLOUD COVER OVER EAST-CENTRAL WISCONSIN TODAY AS 5K-6KFT CLOUDS OVER NORTHERN ILLINOIS WILL LIKELY ARRIVE THIS MORNING. ELSEWHERE...A MID-LEVEL DECK OVER MINNESOTA AND IOWA WILL SHIFT TO THE EAST AND MOVE INTO NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON. UNTIL THESE CLOUDS ARRIVE...A POCKET OF VERY DRY AIR WILL REMAIN IN PLACE ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN. MIXING WILL NOT BE AS GOOD TODAY DUE TO LIGHTER WINDS ALOFT...BUT STILL LOWERED DEWPOINTS SINCE THINK WILL STILL BE ABLE TO TAP INTO SOME OF THE BONE DRY AIR JUST ABOVE THE INVERSION. AS A RESULT...HAVE DROPPED DEWPOINTS AND HUMIDITIES OVER CENTRAL AND NORTH-CENTRAL WISCONSIN THIS AFTERNOON. HUMIDITIES COULD FALL BETWEEN 20-25 PCT. FORTUNATELY...WINDS WILL BE MUCH LIGHTER TODAY...SO SHOULD NOT SEE A REPEAT OF THE CRITICAL FIRE WEATHER CONDITIONS. HIGHS MAINLY IN THE MID TO UPPER 60S AWAY FROM LAKE MICHIGAN. TONIGHT...A COLD FRONT WILL DECAY AS IT MOVES INTO NORTH-CENTRAL WISCONSIN LATE. MID-LEVEL CLOUDS WILL CONTINUE TO SPREAD EAST AHEAD OF THE FRONT...BUT GRADUALLY DISSIPATE IN THE PROCESS. SHOULD THEREFORE SEE A PARTLY CLOUDY TO MOSTLY CLEAR NIGHT. WITH THE THINNING CLOUDS...DO NOT THINK THERE WILL BE A DEEP ENOUGH CLOUD LAYER FOR SPRINKLES OR LIGHT SHOWERS. LOWS MAINLY IN THE LOW TO MID 40S. FRIDAY...THE FRONT WILL WASH OUT ACROSS NORTHERN WISCONSIN. MAY SEE SOME CU DEVELOP OVER CENTRAL AND EAST-CENTRAL WISCONSIN DURING THE AFTERNOON...BUT THE NORTH SHOULD SEE AN INFLUX OF DRY AIR...THAT WILL DROP HUMIDITIES NEAR 25 PCT IN THE AFTERNOON. HIGHS WILL BE WARMER THAN TODAYS READINGS...AND RAISED THEM INTO THE UPPER 60S NORTH TO MID 70S SOUTH. .LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY ISSUED AT 257 AM CDT THU APR 16 2015 DRY CONDITIONS WILL CONTINUE FRIDAY NIGHT AND SATURDAY AS CANADIAN HIGH PRESSURE BUILDS INTO THE STATE. NORTHWEST WINDS WILL TURN TO THE EAST AND NORTHEAST LATE FRIDAY NIGHT AND SATURDAY. SATURDAY AFTERNOON WILL AGAIN FEATURE VERY LOW AFTERNOON RELATIVE HUMIDITY READINGS AWAY FROM THE LAKE...WITH READINGS DROPPING INTO THE 20 TO 40 PERCENT RANGE WITH THE LOWEST READINGS NORTH AND WEST OF THE FOX VALLEY. MEANWHILE...CLOSED UPPER LOW ACROSS THE CENTRAL PLAINS IS EXPECTED TO OPEN UP AS 500MB TROUGH ACROSS SOUTHERN CANADA WILL BEGIN TO LIFT THE SOUTHERN SYSTEM NORTHEAST TOWARDS THE REGION. QUIET A SPREAD IN THE MODELS ON HOW QUICK THE RAIN WILL ARRIVE OVER THE WEEKEND. THE WRF MODELS WAS QUICKEST...ALREADY BRINGING RAIN ON SATURDAY TO PORTIONS OF THE AREA. THE GFS MODEL WAS IN THE MIDDLE OF THE ROAD SOLUTION...WHILE THE CANADIAN/ECMWF MODEL WERE THE SLOWEST SOLUTION WITH RAIN ARRIVING ON SUNDAY. TRENDED TOWARD THE SLOWER SOLUTION FOR THE MEANTIME DUE TO BETTER CONSISTENCY FROM RUN TO RUN. DID ADD A SMALL CHANCE OF RAIN ACROSS THE WEST LATE SATURDAY NIGHT...AND THEN BOOSTED RAIN CHANCES INTO THE LIKELY CATEGORY ON SUNDAY. DID RAISE RAIN CHANCES SUNDAY NIGHT AS WELL. THE 500MB SYSTEMS WILL MERGE INTO A CLOSED UPPER LOW ACROSS THE UPPER MIDWEST AND WESTERN GREAT LAKES REGION EARLY NEXT WEEK. THIS WOULD SUPPORT A COOLER AND UNSETTLED PATTERN ACROSS THE REGION ON MONDAY THROUGH WEDNESDAY. HAVE CHANCES OF SHOWERS EACH PERIOD... ALONG WITH A LITTLE SNOW LATE AT NIGHT INTO THE EARLY MORNING HOURS ON TUESDAY AND WEDNESDAY. IT IS WISCONSIN! TEMPERATURES BY EARLY NEXT WEEK WILL RUN WELL BELOW NORMAL. && .AVIATION...FOR 12Z TAF ISSUANCE ISSUED AT 605 AM CDT THU APR 16 2015 VFR CONDITIONS EXPECTED TODAY AND TONIGHT. SCATTERED LIGHT SHOWERS OVER LAKE MICHIGAN WILL APPROACH MTW THIS MORNING...BUT GUIDANCE KEEPS THIS SHOWER ACTIVITY JUST OFFSHORE. WILL CONTINUE TO MONITOR. OTHERWISE...A BROKEN 6KFT CLOUD DECK WILL MOVE INTO EAST-CENTRAL WISCONSIN THIS MORNING BEFORE DEPARTING EARLY IN THE AFTERNOON. THEN SCT TO BKN MID CLOUDS WILL MOVE ACROSS THE REGION FROM WEST TO EAST LATE THIS AFTERNOON INTO TONIGHT. NO PRECIPITATION IS EXPECTED. && .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 FRIDAY ISSUED AT 257 AM CDT THU APR 16 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE CENTERED OVER THE EAST COAST...BUT WITH A RIDGE AXIS EXTENDING WEST TO THE WESTERN GREAT LAKES. VERY DRY AIR CONTINUES TO HOLD ON ACROSS THE REGION...AND DEWPOINTS HAVE STRUGGLED TO RECOVER OVER CENTRAL AND NORTH-CENTRAL WISCONSIN OVERNIGHT. SOUTHEAST LOW LEVEL FLOW OVER THE SOUTHERN GREAT LAKES IS SLOWLY VEERING TO MORE OF A SOUTHERLY DIRECTION...BUT IS STILL TRYING TO PUSH LIGHT SHOWER ACTIVITY ACROSS SOUTH-CENTRAL LAKE MICHIGAN. THIS IS AHEAD OF A SHORTWAVE OVER THE IL/IN BORDER. THE BONE DRY AIRMASS AND VEERING FLOW IS NOT HELPING THESE SHOWERS TO MAKE A WESTWARD JAUNT...AND THE LATEST MESOMODELS KEEP THESE SHOWERS EAST OF THE MANITOWOC SHORELINE EARLY THIS MORNING. THIS SHOWER ACTIVITY ALONG WITH FIRE WEATHER CONDITIONS ARE THE MAIN FORECAST CONCERNS IN THE SHORT TERM. TODAY...THE SHORTWAVE OVER THE IL/IN BORDER WILL LIFT NE THIS MORNING AND THEN EAST THIS AFTERNOON AS RIDGING OVER THE GREAT LAKES FLATTENS. 850MB FLOW WILL CONTINUE TO VERY GRADUALLY VEER THIS MORNING WHICH COMBINED WITH THE VERY DRY AIR ACROSS THE REGION WILL GIVE THE LIGHT SHOWER ACTIVITY OVER SOUTHERN LAKE MICHIGAN A SUBTLE PUSH TO THE EAST. SO WILL KEEP THE DRY FORECAST IN TACT...BUT WILL INCREASE CLOUD COVER OVER EAST-CENTRAL WISCONSIN TODAY AS 5K-6KFT CLOUDS OVER NORTHERN ILLINOIS WILL LIKELY ARRIVE THIS MORNING. ELSEWHERE...A MID-LEVEL DECK OVER MINNESOTA AND IOWA WILL SHIFT TO THE EAST AND MOVE INTO NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON. UNTIL THESE CLOUDS ARRIVE...A POCKET OF VERY DRY AIR WILL REMAIN IN PLACE ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN. MIXING WILL NOT BE AS GOOD TODAY DUE TO LIGHTER WINDS ALOFT...BUT STILL LOWERED DEWPOINTS SINCE THINK WILL STILL BE ABLE TO TAP INTO SOME OF THE BONE DRY AIR JUST ABOVE THE INVERSION. AS A RESULT...HAVE DROPPED DEWPOINTS AND HUMIDITIES OVER CENTRAL AND NORTH-CENTRAL WISCONSIN THIS AFTERNOON. HUMIDITIES COULD FALL BETWEEN 20-25 PCT. FORTUNATELY...WINDS WILL BE MUCH LIGHTER TODAY...SO SHOULD NOT SEE A REPEAT OF THE CRITICAL FIRE WEATHER CONDITIONS. HIGHS MAINLY IN THE MID TO UPPER 60S AWAY FROM LAKE MICHIGAN. TONIGHT...A COLD FRONT WILL DECAY AS IT MOVES INTO NORTH-CENTRAL WISCONSIN LATE. MID-LEVEL CLOUDS WILL CONTINUE TO SPREAD EAST AHEAD OF THE FRONT...BUT GRADUALLY DISSIPATE IN THE PROCESS. SHOULD THEREFORE SEE A PARTLY CLOUDY TO MOSTLY CLEAR NIGHT. WITH THE THINNING CLOUDS...DO NOT THINK THERE WILL BE A DEEP ENOUGH CLOUD LAYER FOR SPRINKLES OR LIGHT SHOWERS. LOWS MAINLY IN THE LOW TO MID 40S. FRIDAY...THE FRONT WILL WASH OUT ACROSS NORTHERN WISCONSIN. MAY SEE SOME CU DEVELOP OVER CENTRAL AND EAST-CENTRAL WISCONSIN DURING THE AFTERNOON...BUT THE NORTH SHOULD SEE AN INFLUX OF DRY AIR...THAT WILL DROP HUMIDITIES NEAR 25 PCT IN THE AFTERNOON. HIGHS WILL BE WARMER THAN TODAYS READINGS...AND RAISED THEM INTO THE UPPER 60S NORTH TO MID 70S SOUTH. .LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY ISSUED AT 257 AM CDT THU APR 16 2015 DRY CONDITIONS WILL CONTINUE FRIDAY NIGHT AND SATURDAY AS CANADIAN HIGH PRESSURE BUILDS INTO THE STATE. NORTHWEST WINDS WILL TURN TO THE EAST AND NORTHEAST LATE FRIDAY NIGHT AND SATURDAY. SATURDAY AFTERNOON WILL AGAIN FEATURE VERY LOW AFTERNOON RELATIVE HUMIDITY READINGS AWAY FROM THE LAKE...WITH READINGS DROPPING INTO THE 20 TO 40 PERCENT RANGE WITH THE LOWEST READINGS NORTH AND WEST OF THE FOX VALLEY. MEANWHILE...CLOSED UPPER LOW ACROSS THE CENTRAL PLAINS IS EXPECTED TO OPEN UP AS 500MB TROUGH ACROSS SOUTHERN CANADA WILL BEGIN TO LIFT THE SOUTHERN SYSTEM NORTHEAST TOWARDS THE REGION. QUIET A SPREAD IN THE MODELS ON HOW QUICK THE RAIN WILL ARRIVE OVER THE WEEKEND. THE WRF MODELS WAS QUICKEST...ALREADY BRINGING RAIN ON SATURDAY TO PORTIONS OF THE AREA. THE GFS MODEL WAS IN THE MIDDLE OF THE ROAD SOLUTION...WHILE THE CANADIAN/ECMWF MODEL WERE THE SLOWEST SOLUTION WITH RAIN ARRIVING ON SUNDAY. TRENDED TOWARD THE SLOWER SOLUTION FOR THE MEANTIME DUE TO BETTER CONSISTENCY FROM RUN TO RUN. DID ADD A SMALL CHANCE OF RAIN ACROSS THE WEST LATE SATURDAY NIGHT...AND THEN BOOSTED RAIN CHANCES INTO THE LIKELY CATEGORY ON SUNDAY. DID RAISE RAIN CHANCES SUNDAY NIGHT AS WELL. THE 500MB SYSTEMS WILL MERGE INTO A CLOSED UPPER LOW ACROSS THE UPPER MIDWEST AND WESTERN GREAT LAKES REGION EARLY NEXT WEEK. THIS WOULD SUPPORT A COOLER AND UNSETTLED PATTERN ACROSS THE REGION ON MONDAY THROUGH WEDNESDAY. HAVE CHANCES OF SHOWERS EACH PERIOD... ALONG WITH A LITTLE SNOW LATE AT NIGHT INTO THE EARLY MORNING HOURS ON TUESDAY AND WEDNESDAY. IT IS WISCONSIN! TEMPERATURES BY EARLY NEXT WEEK WILL RUN WELL BELOW NORMAL. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1021 PM CDT WED APR 15 2015 VFR CONDITIONS EXPECTED TONIGHT INTO THURSDAY. LIGHT EAST WIND AT THE SURFACE WILL PREVAIL TONIGHT INTO THURSDAY BEFORE TURNING VARIABLE OVER CENTRAL AND NORTH CENTRAL WISCONSIN WITH A WEAK FRONTAL BOUNDARY. A WEAK DISTURBANCE WILL SLIDE OVER SOUTHEAST WISCONSIN LATER TONIGHT INTO THURSDAY MORNING. A FEW SPRINKLES BUT MORE THAN LIKELY VIRGA MAY FALL FROM A MID LEVEL DECK OF CLOUDS OVER EAST CENTRAL WISCONSIN TOWARD THURSDAY MORNING. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
435 AM MDT THU APR 16 2015 .SHORT TERM...(TODAY THROUGH FRIDAY NIGHT) ISSUED AT 435 AM MDT THU APR 16 2015 SIGNIFICANT STORM STILL EXPECTED TO IMPACT THE HIGHER ELEVATIONS FROM LATE THIS AFTERNOON THROUGH MIDDAY FRIDAY. WATER VAPOR IMAGERY SHOWS THE CLOSED UPPER LOW SPINNING JUST WEST OF THE FOUR CORNERS REGION. WE ARE GETTING A BREAK IN THE PRECIP...HOWEVER THIS WILL LIKELY BE SHORT LIVED (ONLY THROUGH THIS MORNING) AS CLOUD TOPS ARE COOLING IN COLORADO. THE MODELS CONTINUE TO INDICATE EXCELLENT LARGE SCALE LIFT DEVELOPING IN AREAS ALONG THE COLORADO BORDER BY LATE THIS AFTN. UPWARD VERTICAL MOTION IS MAXIMIZED FROM 21Z THIS AFTN THROUGH 12Z FRI IN THE SOUTHERN HALF OF THE CWA. THIS IS DUE TO EXCELLENT UPPER LEVEL DIFFLUENCE AND ISENTROPIC LIFT. WHILE WIDESPREAD SUBSTANTIAL QPF AMOUNTS ARE VERY LIKELY...THE TRICKIER PART OF THIS FCST INVOLVED THE SNOW LEVEL AND ASSOCIATED SNOW ACCUMULATIONS. THE 00Z GUIDANCE CAME IN A BIT WARMER THAN YESTERDAY WITH RESPECT TO SFC TEMPS FROM LATE THIS AFTN THROUGH FRIDAY MORNING. WARM AIR ADVECTION IS OCCURRING AS 700MB TEMPS AT CHEYENNE RISE FROM -4C THIS MORNING TO -1C BY FRI MORNING. THE CYS SOUNDING FROM BOTH THE NAM AND GFS SHOW SFC TEMPS OF 2-3C WITH COMPLETE SATURATION THROUGH TONIGHT. THUS...DESPITE THE STRONG LLVL LIFT...THINKING IS THAT A MIX OF RAIN/SNOW OR ALL RAIN WILL OCCUR BETWEEN ELEVATIONS OF 6250-5500 FT WITH THIS EVENT. DECIDED TO CANCEL THE WINTER STORM WATCH FOR CENTRAL LARAMIE COUNTY AND EAST PLATTE COUNTY WITH THIS REASONING...AND WILL LET DAY SHIFT SEE IF THE 12Z GUIDANCE COMES IN ANY COOLER OR IF ANY DRIER AIR COULD CAUSE SOME WET-BULBING. THE PRECIP WILL START OUT AS ALL SNOW AT ELEVATIONS ABOVE 6500 FT THIS AFTN AND EARLY EVENING...WITH THE SNOW LEVEL POSSIBLY RISING TO AROUND 7500 FT BY FRI MORNING. THE WINTER STORM WATCH WAS UPGRADED TO A WARNING FROM JUST WEST OF CHEYENNE TO ARLINGTON AND ALSO FOR THE SNOWY RANGE. WHILE TRAVEL WILL BE AFFECTED ALONG INTERSTATE 80 FROM CHEYENNE TO ARLINGTON...THE BIGGEST IMPACTS WILL LIKELY BE OVER THE FROM BUFORD TO THE INTERSTATE 80 SUMMIT WHERE UP TO A FOOT OF SNOW IS FCSTED. BY FRI AFTN THE UPPER LOW WILL HAVE MOVED INTO CENTRAL COLORADO. THE MODELS SHOW VERY GOOD LIFT AND WIDESPREAD PRECIP ACROSS THE CWA THROUGH THE AFTN. DECIDED TO END THE WINTER STORM HIGHLIGHTS AT 18Z FRI AS SFC TEMPS WILL LIKELY BE ABOVE FREEZING ACROSS ALL ZONES EXPECT MAYBE THE HIGHER ELEVATIONS OF THE SNOWY RANGE. THE BAND OF PRECIP IS PROGGED TO SHIFT NORTHWARD FROM NORTHERN CARBON TO THE NORTHERN NEBRASKA PANHANDLE BY FRI EVENING. IT IS AT THIS TIME THAT DRIER AIR WILL WORK INTO THE SOUTHERN HALF OF THE CWA AND PRECIP WILL DIMINISH. WITH MOST OF THE MODELS INDICATING QPF AMOUNTS OF 1.25-2.0 INCHES FROM THIS AFTERNOON THROUGH FRIDAY NIGHT FOR AREAS ALONG AND EAST OF THE LARAMIE RANGE...CONFIDENCE IS HIGH THAT THIS SYSTEM WILL BRING WELL NEEDED MOISTURE TO THE REGION. .LONG TERM...(SATURDAY THROUGH WEDNESDAY) ISSUED AT 435 AM MDT THU APR 16 2015 A COOL AND SHOWERY PERIOD STILL EXPECTED ACROSS THE CWFA THIS WEEKEND AND EARLY NEXT WEEK AS NORTHWEST FLOW PREVAILS. REMNANTS OF THE UPPER LOW THAT WILL HAVE WOBBLED AROUND COLORADO FOR THE BETTER PART OF 3 DAYS LATE THIS WEEK...WILL CARRY LINGERING IMPACTS ACROSS THE REGION EVEN INTO SATURDAY. 00Z MEDIUM RANGE GUIDANCE ARE CONSISTENT IN PINWHEELING A FINAL VORT LOBE SOUTH TO NORTH THRU THE AREA ON SATURDAY. MODELS TARGET WRN AND NRN ZONES WITH THE BEST AXIS OF PRECIP ON SATURDAY...THOUGH COOL MID-LEVEL TEMPS WILL BE ENOUGH TO PRODUCE THE POSSIBILITY OF SHOWERS EVERYWHERE. FINALLY...THE UPPER-LOW WILL FULLY PHASE INTO THE NRN STREAM BY SUNDAY. 00Z MODELS HAVE TRENDED DEEPER/STRONGER WITH KICKER SYSTEM HOWEVER. THIS WILL RE-ENFORCE PRECIP CHANCES FOR SUNDAY. IT LOOKS SOMEWHAT DRIER MON-TUE...THOUGH STILL CANT COMPLETELY RULE OUT SOME LIGHT SHOWER ACTIVITY ESPECIALLY IN AND AROUND THE HIER TERRAIN. ANOTHER WEAK SHORTWAVE MAY BRING ADDL SHOWER CHANCES TO THE AREA WED-THU. NONE OF THESE SHOWER CHANCES WILL AMOUNT TO MUCH THO. TEMPS WILL BE THE COOLEST THIS WEEKEND WITH HIGHS ONLY REACHING THE UPPER 40S TO NR 50 IN AND AROUND THE MOUNTAINS WITH 50S TO NR 60 OUT ON THE ERN PLAINS. THESE SHOULD WARM BACK INTO THE 50S AND MID 60S MON-WED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1034 PM MDT WED APR 15 2015 LATEST HRRR GUIDANCE USED FOR THE 06Z TAFS. WIDESPREAD IFR/LIFR WITH NORTHEAST UPSLOPING FLOW. PRECIP BECOMES WIDESPREAD THURSDAY AFTERNOON...WITH A POSSIBLE HEAVY SNOW EVENT THURSDAY NIGHT INTO FRIDAY MORNING FOR SOUTHEAST WYOMING AND A WIDESPREAD MODERATE RAIN EVENT FOR THE PANHANDLE AIRPORTS. && .FIRE WEATHER... ISSUED AT 347 AM MDT THU APR 16 2015 NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. A COOL AND VERY WET PATTERN WILL BE IN PLACE THROUGH FRIDAY. WIDESPREAD RAIN ACROSS THE LOWER ELEVATIONS AND SNOW IN THE MOUNTAINS WILL OCCUR. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO NOON MDT FRIDAY FOR WYZ114>117. WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO NOON MDT FRIDAY FOR WYZ103-105-106-110-112. NE...NONE. && $$ SHORT TERM...ZF LONG TERM...CAH AVIATION...GCC FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1046 PM MDT WED APR 15 2015 .UPDATE... ISSUED AT 1034 PM MDT WED APR 15 2015 RADAR CONTINUES TO SHOW MOISTURE STREAMING NORTH OUT OF NORTHERN COLORADO THIS EVENING. WITH REPORTS OF 5-6 INCHES OF SNOW IN LARAMIE...WENT AHEAD AND EXPANDED THE ADVISORY SOUTH AS WE COULD SEE ANOTHER 1-3 INCHES OVERNIGHT. ATTENTION TURNS TO THURSDAY NIGHT AS LOW IN COLORADO SPINS OFF ANOTHER STRONGER PIECE OF ENERGY INTO THE LARAMIE RANGE. GUIDANCE SHOWING QPFS WELL OVER AN INCH BEGINNING THURSDAY AFTERNOON AND PERSISTING INTO FRIDAY MORNING. WENT AHEAD WITH A WINTER STORM WATCH FOR THE MOUNTAINS...ADJACENT FOOTHILLS AND THE SNOWY RANGE. UPDATES SENT OUT EARLIER. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 311 PM MDT WED APR 15 2015 TRICKY FORECAST THIS PERIOD WITH MAIN DIFFICULTIES BEING SNOW LEVELS AND SNOWFALL AMOUNTS...AND AT WHAT TIMES THE HEAVIER PRECIPITATION WILL OCCUR. UPPER LOW TAKING SHAPE ALONG THE UTAH/COLORADO BORDER CURRENTLY WITH AREAS OF RAIN AND SNOW ALONG AND WEST OF THE LARAMIE RANGE. SOME CONVECTIVE ACTIVITY MOVING NORTH TOWARDS THE NEB PANHANDLE FROM COLORADO AS WELL WITH A FEW LIGHTNING STRIKES NOTED IN THIS ACTIVITY. EXPECT ALL THIS ACTIVITY TO CONTINUE MOVING NORTH AHEAD OF AN IMPULSE RIDING UP THE EAST SIDE OF THE UPPER LOW THIS EVENING THEN THERE SHOULD BE SOME LULL IN THE PCPN OVER THE SOUTHERN PARTS OF THE CWA LATER THIS EVENING INTO THURSDAY BEHIND THE IMPULSE WHILE THE MAIN UPPER LOW SINKS SLOWLY SOUTHWARD TO THE 4 CORNERS AREA. WILL MAINTAIN CURRENT WINTER WX ADVY AS IS AS THAT AREA SHOULD STILL SEE MOSTLY SNOW. CONDITIONS DETERIORATE AGAIN THURSDAY NIGHT AS THE UPPER LOW DRIFTS SLOWLY ENE ACROSS COLORADO WITH NEXT SHORTWAVE LIKELY ROTATING NORTH AND ACROSS THE CWA LATER THURSDAY NIGHT INTO FRIDAY. HEAVIEST PCPN LOOKS LIKE IT WILL OCCUR THEN AND COULD GET SOME DECENT SNOWS OVER HIGHER TERRAIN. 700MB TEMPS A BIT WARM HOWEVER...ABOUT -2C...AND WARM GROUND MAY HINDER ACCUMULATIONS SOME. WILL HOLD OFF ON ADDITIONAL HILITES AT THIS TIME AND LET LATER SHIFTS LOOK AT NEWER RUNS. PCPN STILL FAIRLY WIDESPREAD ON FRIDAY INTO FRIDAY NIGHT THOUGH MORE LIKELY OVER THE NORTH AS THE IMPULSE CONTINUES TO RIDE NORTH AND NORTHWEST. SNOW LEVELS ALSO RISING AS THE UPPER LOW FILLS SOME. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 311 PM MDT WED APR 15 2015 UNSETTLED WEATHER WILL CONTINUE THROUGH THE WEEKEND AS A CLOSED LOW TRANSLATES EASTWARD INTO THE CENTRAL PLAINS. PRECIPITATION IS LIKELY TO LINGER THROUGH AT LEAST SUNDAY WITH WEAK MIDLEVEL ENERGY ROTATING WESTWARD ACROSS THE CWA. FAIRLY COOL TOO WITH GFS 700 MILLIBAR TEMPS FAILING TO CLIMB ABOVE 0 DEG C. THE MODELS ARE IN GOOD AGREEMENT W/ A KICKER SYSTEM DIVING INTO THE DAKOTAS AT 12Z SUN. THIS PUSHES THE OTHER SYSTEM TO THE EAST AND SENDS A COLD FRONT SOUTH. MEDIUM RANGE MODELS SHOW ENOUGH H7-H3 MOISTURE TO SUPPORT SHOWERS CONTINUING INTO SUN. WOULD PROBABLY BE COLD ENOUGH FOR ALL SNOW ON SUN...BUT THERMAL PROFILES WOULD SUGGEST ALL RAIN OR A RAIN/SNOW MIX FROM THE NE STATE LINE INTO THE WESTERN PANHANDLE PRIOR TO FROPA. MAINTAINED LOWER END POPS INTO EARLY NEXT WEEK WITH COOL CYCLONIC FLOW ALOFT. INSTABILITY SHOWERS CANNOT BE RULED OUT...SO IT IS HARD TO FORECAST DRY. NOTHING MAJOR THOUGH. TEMPERATURES SHOULD STAY ON THE COOL SIDE FOR MOST OF THE PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1034 PM MDT WED APR 15 2015 LATEST HRRR GUIDANCE USED FOR THE 06Z TAFS. WIDESPREAD IFR/LIFR WITH NORTHEAST UPSLOPING FLOW. PRECIP BECOMES WIDESPREAD THURSDAY AFTERNOON...WITH A POSSIBLE HEAVY SNOW EVENT THURSDAY NIGHT INTO FRIDAY MORNING FOR SOUTHEAST WYOMING AND A WIDESPREAD MODERATE RAIN EVENT FOR THE PANHANDLE AIRPORTS. && .FIRE WEATHER... ISSUED AT 311 PM MDT WED APR 15 2015 CONCERNS EXPECTED TO BE LOW THROUGH THE WEEKEND AS A COOL TO MILD AIRMASS WILL RESIDE OVER THE DISTRICTS WITH PERIODS OF RAIN OR SNOW BRINGING WETTING PRECIPITATION TO MUCH OF THE AREA. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...WINTER STORM WATCH FROM THURSDAY EVENING THROUGH FRIDAY AFTERNOON FOR WYZ103-105>107-110-114>118. WINTER WEATHER ADVISORY UNTIL 9 AM MDT THURSDAY FOR WYZ101- 103>106-109-110-115>117. NE...NONE. && $$ UPDATE...GCC SHORT TERM...RE LONG TERM...CLH AVIATION...GCC FIRE WEATHER...RE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1120 PM MDT FRI APR 17 2015 .UPDATE... ISSUED AT 919 PM MDT FRI APR 17 2015 UPDATED TO MODIFY POPS BASED ON 00Z GUIDANCE...FOCUSING HIGHEST CHANCES OVER THE PIKES PEAK REGION AND UPPER ARKANSAS AND CONTDVD NORTH OF HIGHWAY 50. CUT BACK ON POPS TO THE SOUTH BUT WILL LEAVE ISOLD-SCT CHANCES OUT FOR THE HIGHER TERRAIN WITH THE UPPER LOW OVERHEAD. UPDATE ISSUED AT 844 PM MDT FRI APR 17 2015 MADE SOME ADJUSTMENTS TO THE WINTER HEADLINES BASED ON OBS...TRENDS AND LATEST MODEL GUIDANCE. LOOKS LIKE THE HEAVIEST AND MOST PERSISTENT PRECIP WILL BE OVER THE MTS NORTH OF HGWY 50 TONIGHT AND TOMORROW. SO...HAVE CANCELED THE ADVISORIES FOR THE SANGRES AND WETS. EXTENDED PIKES PEAK AND THE SAWATCH TIL 00Z SUN SINCE IT LOOKS LIKE PERIODS OF MODERATE SNOW WILL CONTINUE TOMORROW. TELLER MAY ALSO HAVE TO BE EXTENDED BUT GIVEN THE UNCERTAINTIES IN HOW THE BAND OF SNOW NORTH OF THE UPPER LOW WILL SET UP...WILL LEAVE THE ENDING TIME FOR SAT MORNING FOR NOW. HRRR HAS MOST OF THE HEAVIER QPF NORTH OF TELLER WHILE THE RAP AND NAM HAVE IT DIRECTLY OVER TELLER. SO...AMOUNTS ARE MOST UNCERTAIN OVER THE PIKES PEAK AREA BUT THE GOING ADVISORY COVERS THAT HAZARD FOR NOW. ROSE && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 256 PM MDT FRI APR 17 2015 CURRENTLY...THE UPPER LOW IS LOCATED OVER THE SW QUAD OF THE STATE THIS AFTERNOON...AND WAS WRAPPING DRY AIR UP INTO PORTIONS OF SOUTH CENTRAL AND SOUTHEAST CO EFFECTIVELY SHUTTING OFF PCPN AND EVEN CLOUD COVER FOR PORTIONS OF THE CWA. BEFORE THE DRY AIR MOVED IN...HEAVY SNOW WAS REPORTED OVER MANY OF THE AREA MTS AS WELL AS THE UPPER ARKANSAS RIVER BASIN...ALONG WITH SIGNIFICANT RAINFALL AMOUNTS ALL ALONG THE I25 CORRIDOR. CLOUD ENHANCEMENT WAS OCCURRING AS OF 3 PM OVER THE S MTS...SLOWLY SPREADING NORTH. FARTHER EAST...DRY AIR PUSHED INTO THE SE CORNER OF THE STATE AND HELPED TO PUSH THE SEVERE THREAT N AND NE. A FEW THUNDERSTORMS HAVE STRUGGLED ACROSS THE PLAINS THIS AFTERNOON AS LOWER DEWPOINTS HAVE ROBBED LOW LEVEL ENERGY. TONIGHT AND TOMORROW...THE MAIN QUESTION IS WHERE WILL THE UPPER LOW GO. MODELS STILL INDICATE THAT IT WILL GRADUALLY MOVE NORTH INTO CENTRAL COLORADO THIS EVENING...THEN EDGE DUE EAST THROUGH TOMORROW AFTERNOON. AFTER A BRIEF LULL...WHICH WILL MOST LIKELY HAVE CUSTOMERS SCRATCHING THEIR HEADS...ALL MODELS INCLUDING THE HI-RES OFFERINGS SHOW SHOWERS REDEVELOPING OVER THE PALMER DVD AND RAMPART RANGE...AS WELL AS THE CENTRAL MTS...N SANGRES AND WETS...THIS EVENING AND OVERNIGHT. ADDITIONAL SNOW AMOUNTS DO NOT LOOK AS SIGNIFICANT NOW AS THEY DID 12 HRS AGO...AND HANDLING OF THE HIGHLIGHTS WAS EXCEPTIONALLY TRICKY. DECIDED TO PUSH ALL ENDING TIMES OF HIGHLIGHTS TO 12Z TOMORROW MORNING...AND CONVERTED SOME OF THE ONGOING WARNINGS TO ADVISORIES. FURTHER ADJUSTMENTS TO THE POP AND HIGHLIGHT GRIDS WILL OCCUR UNDOUBTEDLY. AS FOR TEMPS...FRESH SNOW COVER FOR MUCH OF THE HIGHER TERRAIN AND HIGH VALLEYS WILL MAKE FOR A COLD NIGHT...AS WELL AS MODIFYING THE MAX TEMP TOMORROW DOWNWARD A FEW DEGREES. LOOK FOR MAX TEMPS TOMORROW IN THE 40S TO NEAR 50 F FOR THE HIGH VALLEYS...50S TO LOWER 60S FOR THE E PLAINS...WITH AREAS THAT RECEIVED EXTENSIVE SNOW COVER ON THE LOWER END. MOORE .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 256 PM MDT FRI APR 17 2015 OLD UPPER LOW OPENS UP AND PULLS AWAY TO THE EAST SAT NIGHT/SUNDAY. ANOTHER LOBE OF ENERGY ROTATING AROUND THE BACK SIDE OF THE UPPER LOW WILL SPREAD ANOTHER BAND OF SNOW SHOWERS INTO THE MTS/PALMER DIVIDE SATURDAY EVENING...AND INTO THE SOUTHEAST PLAINS SAT NIGHT/EARLY SUNDAY MORNING. OVERALL ACCUMULATIONS DO NOT LOOK LIKE THEY WILL BE THAT HEAVY...BUT A COUPLE INCHES ACROSS THE CENTRAL MTS AND PIKES PEAK REGION WILL BE POSSIBLE...WITH 1-2 ACROSS THE PALMER DIVIDE. IT WILL BE SOMEWHAT UNSTABLE...SO THERE IS ALWAYS A CHANCE FOR SOME LOCALLY HEAVY BURSTS OF SNOW...BUT THINK THESE SHOULD BE FAIRLY LOCALIZED. MEANWHILE PRECIPITATION WILL FALL AS RAIN ACROSS THE SE PLAINS EARLY BEFORE DIMINISHING BY LATE SUN MORNING. WINDS REALLY INCREASE ACROSS THE AREA FOR SUNDAY BEHIND THE SYSTEM WITH NORTH WINDS GUSTING TO 40 TO 50 MPH ACROSS THE PLAINS. FORTUNATELY MANY PLACES HAVE HAD SOME RAIN...WHICH SHOULD MINIMIZE BLOWING DUST CONCERNS SOME...AND COOLER AIR BEHIND THE SYSTEM SHOULD KEEP RELATIVE HUMIDITY VALUES FROM REACHING CRITICAL LEVELS WHICH SHOULD MITIGATE ANY FIRE WEATHER CONCERNS. NORTHWEST FLOW KEEPS UNSETTLED WEATHER OVER THE REGION FOR MONDAY AND TUESDAY WITH PRIMARILY AFTERNOON AND EVENING SNOW SHOWERS OVER THE MOUNTAINS. ANOTHER REINFORCING NORTHERLY SURGE MOVES THROUGH THE PLAINS ON MONDAY WHICH WILL ENHANCE EASTERLY UPSLOPE FLOW INTO THE SOUTHEAST MOUNTAINS. THIS WILL RESULT IN SCATTERED SNOW SHOWERS AS ANOTHER SHORTWAVE MOVES THROUGH NW FLOW ALOFT. GFS SPREADS THESE SHOWERS EASTWARD ONTO THE PLAINS DURING THE EVENING HOURS THOUGH PRECIPITATION WILL FALL MAINLY AS RAIN. WESTERN U.S UPPER RIDGE TRANSLATES EASTWARD FOR TUESDAY WITH SHOWERS STAYING MORE CONFINED TO THE MOUNTAINS. AGAIN...MAINLY LIGHT ACCUMULATIONS EXPECTED. ANOTHER TROF MOVES INTO THE WESTERN U.S FOR THE LATTER PART OF THE WEEK. UPPER RIDGE AXIS SHIFTS OVER CO FOR WEDNESDAY...THEN GRADUALLY INTO THE PLAINS THURS AND FRI AS THE UPPER TROF MOVES TOWARDS THE GREAT BASIN. LOTS OF VARIABILITY BETWEEN THE LONG RANGE MODELS ON TIMING...BUT BOTTOM LINE IS FOR INCREASING SOUTHWEST FLOW FOR THURSDAY AND FRIDAY...SPREADING A CHANCE OF SNOW SHOWERS INTO THE CONTDVD REGION BY LATE WEEK. TEMPERATURES REBOUND ACROSS THE PLAINS...THOUGH SOUTHEAST FLOW ADVECTS HIGHER DEW POINTS INTO THE PLAINS BRINGING A CHANCE FOR THUNDERSTORMS. AS SOUTHWEST FLOW ALOFT INCREASES...THIS SHOULD HELP DEVELOP A DRY LINE AND PUSH IT EASTWARD ACROSS THE PLAIN...WITH THUNDERSTORMS POSSIBLE ALONG AND TO ITS EAST THURS AFTERNOON. WILL HAVE TO WATCH THIS DEVELOPMENT AS DEEP LAYER SHEAR LOOKS FAVORABLE FOR STRONG TO SEVERE THUNDERSTORMS...IF SUFFICIENT MOISTURE CAN RETURN...BUT GIVEN THE UNCERTAINTIES IN THE EVOLUTION OF THE SYSTEM...THESE DETAILS ARE LIKELY TO EVOLVE OVER THE NEXT SEVERAL DAYS. -KT && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1106 PM MDT FRI APR 17 2015 LARGE UPPER LOW PRESSURE AREA SPINNING OVER THE MOUNTAINS THIS EVENING AND DRIFTING SLOWLY EASTWARD. UPPER LOW HAS WEAKENED CONSIDERABLY FROM THIS TIME YESTERDAY. CONDITIONS ARE MOSTLY VFR ACROSS THE FLIGHT AREA EXCEPT FOR ISOLATED TO SCATTERED SNOW SHOWERS PRODUCING POCKETS OF MVFR/IFR/LIFR FLIGHT CONDITIONS...MAINLY OVER THE MOUNTAINS. UPPER LOW WILL DRIFT SLOWLY EASTWARD INTO SOUTHWEST KANSAS FROM 06Z SATURDAY TO 06Z SUNDAY. AS IT DOES SO...ISOLATED TO SCATTERED SHOWERS WILL CONTINUE OVER THE FLIGHT AREA...RESULTING IN AREAS OF MVFR/IFR FLIGHT CONDITIONS AND POCKETS OF LIFR CONDITIONS UNDER THE HEAVIER PRECIPITATION. KCOS...KPUB AND KALS TAF SITES SHOULD REMAIN GENERALLY VFR THROUGH THE NEXT 24 HOURS. HOWEVER...IT IS POSSIBLE THAT RAIN OR SNOW SHOWERS COULD BRIEFLY IMPACT ANY OF THE TERMINALS...ESPECIALLY KCOS. && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 AM MDT SATURDAY FOR COZ059-063- 066-081. WINTER WEATHER ADVISORY UNTIL 6 PM MDT SATURDAY FOR COZ058-060- 061. WINTER STORM WARNING UNTIL 6 PM MDT SATURDAY FOR COZ082. && $$ UPDATE...ROSE SHORT TERM...MOORE LONG TERM...KT AVIATION...LW
AREA FORECAST DISCUSSION
NWS TOPEKA KS
343 AM CDT Sat Apr 18 2015 .SHORT TERM...(Today and Tonight) Issued at 342 AM CDT SAT APR 18 2015 Showers and thunderstorms developing this hour across northeast Oklahoma into south central and north central Kansas, with cell movement toward the north northwest and the cluster moving more northerly. This area is forecast to move across the forecast area through the morning hours today. Struggle with the forecast continues to be timing and coverage of precipitation chances. After initial energy lifts across Eastern Kansas through early afternoon, next uncertainty will be for chances later in the afternoon. HRRR develops a cluster of showers in south central KS, but would anticipate a break between the systems with subsidence behind the main wave inhibiting convective development. Have higher chances in the morning, with lower chances middle afternoon, followed by an increase from west to east through the evening into the overnight hours as the main wave finally starts to get an easterly push, from both a northern US shortwave and an upper jet traversing the southern states. With a lull in precipitation and possibly some better sunshine out west, this would boost instability and chances for severe thunderstorms as late day storms develop along the dryline to our west and along the northward advancing warm front. Primary threat would be hail, but closer proximity to these surface features in north central Kansas could bring an isolated tornado risk there. General precipitation chances continue in the overnight hours ahead of the upper low as it continues to slowly move east. Highs for Saturday in the middle 70s west to near 70 east, with lows in the 50s. .LONG TERM...(Sunday through Friday) Issued at 342 AM CDT SAT APR 18 2015 By Sunday morning the mid/upper low will be centered over SC KS and NC OK as it progresses eastward. During this time the low will become more of an open wave as another shortwave digs into the northern plains and upper Midwest. These waves will bring a cold front through the region during the day Sunday. In the morning the better chance for showers and some thunder should be in southern KS where the front and mid level low are more coupled in the vertical. By 18Z the models are hinting at an increase of instability on the order of about 1000 j/kg ahead of the front that should stretch across eastern KS. Lapse rates are not overly impressive, and deep layer shear could reach 30 kts. Although the better shear will be further southeast over southern MO where the flow aloft is slightly stronger. Therefore kept a mention of thunderstorms for east central KS during the afternoon. A majority of the precip should clear the area around 03Z in the evening. A sharp pressure gradient behind the front will support northwest surface winds around 15 to 25 mph with gusts as up to 35 mph especially in NC KS. Cold air advection on the backside of the wave drops temps into the lower 40s and upper 30s by Monday morning. Winds do not completely decouple Sunday night so there is little concern for frost. On Monday winds remain gusty with high temps generally around 60 and partly sunny skies. Monday night will not be the classic set up for frost with a expansive high building southward, but the winds do decrease and temps are forecast to reach the mid to upper 30s. Therefore could not rule out the possibility for frost perhaps in preferred sheltered locations. NW flow aloft develops over the region as the northern stream wave deepens over the Great Lakes. The models are beginning to advertise embedded shortwaves within the NW flow, which track over the plains around mid week. This will bring small chances for either showers or thunderstorms. Late in the week a southern wave crashes the southern CA coast and tracks northeastward towards the center of the country. There are some differences on how far north the instability reaches ahead of the system, and there are additional waves in the NW flow that could interfere with the southern stream system. Confidence in any solution is low at this point. && .AVIATION...(For the 06Z TAFs through 06Z Saturday Night) Issued at 1134 PM CDT FRI APR 17 2015 Tricky forecast period as short term guidance has had difficulty in determining timing and location of precip thru 12Z. However latest models continue to show sct showers with a few embedded TSRA impacting sites after 07Z at KMHK and 08Z at KTOP/KFOE. May see brief MVFR conditions shortly after sunrise with the heavier precip before it exits eastward early afternoon. Low confidence thereafter as main system does not arrive into the area until Sunday morning so will leave mention of VCTS. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...67 LONG TERM...Sanders AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1139 PM CDT Fri Apr 17 2015 ...Update to aviation forecast discussion... .SHORT TERM...(This Evening through Saturday) Issued at 346 PM CDT FRI APR 17 2015 Upper low continues to spin over the Rockies this afternoon with an upper level jet rounding the base of the upper low and moving over New Mexico. Earlier showers and thunderstorms were moving out of the northern counties at 20Z. Some clearing was occurring across the southern and western sections of the cwa this afternoon. Latest meso analysis shows surface based CAPE around 500 to 1000 J/kg with an uncapped atmosphere. Expect scattered convection to develop in southwest Kansas along the dry line. additional scattered storms may develop in south west and south central Kansas per the latest runs of the RAP and HRRR. Models suggest additional development this evening across western and central Kansas moving northeast into north central Kansas with the increase and veering of the low level jet overnight. Models are in agreement with a lobe of energy working it`s way northeast out of Oklahoma later tonight and Saturday morning. May see a repeat of this morning with an area of showers and embedded thunderstorms moving across the area. Expect a break for a few hours in the afternoon, then chances increase again with storms developing again in the afternoon in western and central Kansas as upward vertical motion increases with the advance of the upper trough into the High Plains. Dryline looks to set up across western Kansas with the GFS the furthest east in central Kansas. Shear and instability will be favorable for some of the storms to be strong to severe with large hail and winds the main hazards in the late afternoon hours mainly west of a Herington to Washington line. .LONG TERM...(Saturday Night through Friday) Issued at 346 PM CDT FRI APR 17 2015 Short range models are relatively consistent in moving surface low and main piece of upper trough through eastern KS late Saturday night and Sunday. Ahead of this system Saturday night, increasing thunderstorm chances are expected, with some potential for severe weather, with the best chance in our forecast area over the western 2/3. Shear parameters are not very impressive and amount of sunshine and associated surface heating Sat afternoon and evening is also a little suspect so this is not a high probability thing. As the low and front move through on Sunday, some isolated thunder may continue in the east in the morning, but showers associated with cold air aloft just behind the front will continue precip chances into the afternoon hours. After that, subsidence and cold advection behind that system brings in dry conditions and cooler temperatures for Sunday night through Tuesday, with lows dipping into the upper 30s many places and highs in the low to mid 60s. Precip chances return to parts of eastern KS on Wednesday when weak low-level warm advection and a weak wave in northwest flow aloft interact. Latest ECMWF and GEM would indicate that the cool air at the surface is more entrenched in place than the GFS, thus have gone cooler than guidance for highs on Wednesday. Beyond Wednesday, considerable differences exist between 12Z GFS and ECMWF in upper flow pattern and precip chances. GFS and GFSEnsemble places us in a more favorable pattern for a couple days of precip for Thursday and Friday, while the ECMWF is slower in bringing a shortwave trough out of the southwest U.S., and would give us the better chances on Friday. Have gone with a general compromise with 25 to 40 percent POPs for those days. && .AVIATION...(For the 06Z TAFs through 06Z Saturday Night) Issued at 1134 PM CDT FRI APR 17 2015 Tricky forecast period as short term guidance has had difficulty in determining timing and location of precip thru 12Z. However latest models continue to show sct showers with a few embedded TSRA impacting sites after 07Z at KMHK and 08Z at KTOP/KFOE. May see brief MVFR conditions shortly after sunrise with the heavier precip before it exits eastward early afternoon. Low confidence thereafter as main system does not arrive into the area until Sunday morning so will leave mention of VCTS. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...53 LONG TERM...GDP AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
412 AM CDT Sat Apr 18 2015 .DISCUSSION... Issued at 411 AM CDT SAT APR 18 2015 Overview: Closed and cut-off upper low now over central CO will be the primary weather driver for the weekend. Feature will open up by Sunday and move east in response to a shortwave trough digging southeast through the Northern Rockies. Expect to see a several rounds of active convection Saturday and Sunday. Today - Sunday: While eyes have been fixated on the closed upper low now over CO/NM the real weather makers will be periodic vorticity lobes and associated layered frontogenesis that rotate northeast out from under the upper low. Little going on over the CWA early this morning as we`re lacking any discernible feature to initiate any convection. But we are finally seeing the long awaited next round of convection. Regional radars have recently lit up from OK northward through central KS albeit further west than we`ve been expecting. Favor following the HRRR reflectivity trends, which have slowed down the arrival of the KS/OK convection and latest NAM mass fields/h7 vorticity prog. Thus have pared back PoPs significantly for first part of morning and slowed the eastward expansion of precipitation. Even still this is a forecast which will need adjusting throughout the day as the convection tied to the upper low has had repeated false starts as well as expanding too fast to the east. Thickening cloud cover and rain-cooled air will affect temperatures over the western half of the CWA more so than the eastern half where precipitation will move in later in the day. Precipitable water values around two standard deviations above normal suggest potential for 1"+ rains through tonight. Weak shear and MUCAPEs under 1000J/kg favor convection remaining below severe limits. Should see a lull in the rain later tonight and first part of Sunday before the next wave of convection moves in. The upper low will have opened up by then and will accelerate eastward. Anticipate convection increasing as it moves east through the CWA in response to improving upper level dynamics and low-level convergence associated with a cold front. However, once again the 0-6km shear of 20-25kts and modest MUCAPEs favor convection being sub-severe. Monday - Tuesday: A fairly deep upper trough stretching from MN through the Mid MS Valley will influence our weather with widespread subsidence on the backside of the trough. Abundant solar insolation will help offset cold air advection but still result in below average temperatures. Wednesday - Friday: As the upper trough shifts east through the Great Lakes an upper ridge will build eastward through the Rockies and into the Central/Southern Plains. Medium range models are in agreement that a cold front will surge through the region on Wednesday. However, they disagree on whether or not convection will be generated. Moisture fields look minimal and believe any shower activity will be widely scattered. As we get into Thursday and Friday the ECMWF and GFS both lift a shortwave out of the southwestern U.S. but the GFS appears unrealistic in deepening a surface over the Central High Plains and spreading warm advection convection too far downstream. Will use a blended forecast but overall confidence low for Thursday`s PoPs but timing looks better for the PoPs on Friday. && .AVIATION...(For the 06Z TAFS through 06Z Saturday Night) Issued at 1129 PM CDT FRI APR 17 2015 VFR conditions will likely prevail at the terminals through the rest of the overnight hours as the forecast for storms looks to have slowed. Storms still look likely in the morning, but now it appears that it will be after sunrise before anything sweeps across our terminals. Thunderstorms are forecast to redevelop in the late afternoon hours. Otherwise, easterly surface wind overnight will veer to the south through the morning hours, with speeds remaining less then 10 knots. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ UPDATE...Cutter DISCUSSION...MJ AVIATION...Cutter
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
328 AM CDT SAT APR 18 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 328 AM CDT SAT APR 18 2015 SPC SUGGESTED SIGNIFICANT SEVERE WEATHER POTENTIAL THIS AFTERNOON AND EARLY THIS EVENING ACROSS PARTS OF SOUTHWEST AND NCNTL NEB. A PORTION OF THE LOW PRESSURE ACROSS SWRN KS THIS MORNING IS EXPECTED TO LIFT NORTHEAST THROUGH SCNTL AND ERN NEB THIS AFTERNOON SETTING UP A UNSTABLE WARM SECTOR FROM ROUGHLY IMPERIAL TO ONEILL. ALTHOUGH THE RAP IS FAIRLY QUIET THE NAM AND HRRR SBN MODELS SUGGEST REASONABLE POTENTIAL FOR CONVECTIVE DEVELOPMENT THIS AFTN IF SKIES PARTIALLY CLEAR ALLOWING FOR TEMPERATURES TO RISE INTO THE MID AND UPPER 60S. SATELLITE SHOWS CLEARING THIS MORNING ACROSS CNTL HIGH PLAINS OF KS/COLO AND IT IS BELIEVED THIS CLEARING WILL MOVE INTO SCNTL NEB THIS AFTN. THE STORM ACTIVITY COULD BEGIN AS EARLY AS 18Z IN THE SOUTHWEST WITH THE NAM SOLN OR AS LATE AS 21Z-00Z IN THE HRRR MODEL. SATELLITE TIMING TOOLS INDICATE THE CLEARING ACROSS KS COULD REACH SOUTHWEST NEB BY 13-15Z THIS MORNING WHICH WOULD PROVIDE A GOOD START FOR MODEST HEATING GIVEN THAT THIS CLEARING AREA WOULD TEND TO FILL IN WITH DEVELOPING CUMULUS. ONE WEAKNESS ARE THE WIND FIELDS 500MB AND BELOW WHICH ARE LIGHT PRODUCING BULK SHEAR VALUES OF 30KT OR LESS WHICH MIGHT SUPPORT MORE OF HEAVY RAIN THREAT. STILL TEMPERATURES ALOFT WILL BE VERY COLD AS THE H500MB LOW ACROSS COLO MOVES EAST TO NEAR LIMON/SPRINGFIELD. WINDS AT 300MB ARE STRONG NEAR 65KT POTENTIALLY ENHANCING UPDRAFTS AND PROVIDING VENTILATION. FREEZING LEVELS ARE NEAR 5KFT SUPPORTING A LOW TOP STORM ENVIRONMENT AND GOOD POTENTIAL FOR HAIL. THE NAM IS PRODUCING AROUND 2000 J/KG OF CAPE AT NORTH PLATTE AND BROKEN BOW WHILE THE RAP AND OTHER MODELS SHOW HALF OR LESS THAT VALUE. NORTHWEST WINDS WILL SWEEP IN FROM THE WEST IN THE WAKE OF THE DISTURBANCE TONIGHT. THIS SHOULD PRODUCE DRYING AND DECREASING RAIN CHANCES FROM MIDNIGHT ONWARD. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 328 AM CDT SAT APR 18 2015 SUNDAY WILL SEE THE STRONG LOW PRESSURE WEAKENING AS IT PUSHES EAST WHILE A TROUGH DIGS ACROSS THE CANADIAN PLAINS. SOME LINGERING SUNDAY MORNING SHOWERS ARE POSSIBLE IN THE EASTERN ZONES...HOWEVER THE BIGGER EVENTS OF THE DAY WILL BE THE CAA AND INCREASING NW WINDS. AS THE LOW PUSHES ACROSS KS...DRY AIR WILL QUICKLY FILL IN BEHIND...RESULTING IN DECREASING CLOUDS FROM WEST TO EAST IN THE MORNING. BY AFTERNOON SHOULD SEE MOSTLY SUNNY SKIES FOR ALL. THE SUN WILL COMBINE WITH THE STRONG NW WINDS /GUSTING TO 30 TO 40 MPH/ TO PROMOTE GOOD MIXING OF THE BL AND OFFSET THE CAA AND TEMPS PUSH INTO THE 50S. EARLY IN THE WEEK THE TROUGH DIGS TOWARDS THE GREAT LAKES REGION AND ABSORBS THE SOUTHERN LOW. ELONGATED SFC HIGH PRESSURE BUILDS ACROSS THE HIGH PLAINS. THE ACTIVE WEATHER IS WELL TO THE NE ALTHOUGH A FEW UPPER LEVEL DISTURBANCES WILL RIDE ALONG THE NW FLOW OVERHEAD AND BRING SOME PASSING CLOUDS AT TIMES. LIMITED MOISTURE IN THE LOWER LEVELS AND MODELS/FORECAST ARE DRY. TEMPS TO START THE WEEK WILL BE CHILLY IN THE MORNING WITH MOST AREAS NEAR OR BELOW THE FREEZING MARK. STILL A COUPLE OF WEEKS FROM TYPICAL LAST FREEZE FOR MOST OF THE AREA...SO NO HEADLINES NEEDED YET. HIGHS REBOUND NICELY WITH A WARMING TREND WITH 60S MAYBE 70 FOR WED AND THURS. EYES THEN FOCUS ON A TROUGH AS IT DIGS ACROSS THE SOUTHWEST. MODELS IN GOOD AGREEMENT DEVELOPING A CLOSED 500 MB LOW NEAR SRN CAL BY THURS. THE LOW THEN LIFTS TOWARDS THE 4 CORNERS WHILE BECOMING AN OPEN WAVE. THE WAVE WILL THEN PUSH ACROSS THE PLAINS TO END THE WEEK. THIS WILL BRING A RETURN OF THE ACTIVE WEATHER...AND WILL HAVE POPS TOWARDS THE END OF THE EXTENDED PERIOD. STILL HAVE SOME LOCATION AND TIMING ISSUES TO IRON OUT WHICH IS TYPICAL THIS FAR OUT SO POPS KEPT BELOW 50 PERCENT FOR NOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1213 AM CDT SAT APR 18 2015 THUNDERSTORMS IN SOUTHWEST NEBRASKA WILL STILL BE CAPABLE OF PRODUCING HAIL AND HEAVY RAIN THROUGH THE NIGHT INTO EARLY SATURDAY. AS FOR HAVING THUNDER AT ANY ONE POINT...THE PROBABILITY IS LOW. PROJECTING FROM THE CURRENT RADAR IMAGERY INDICATES THAT THUNDERSTORMS WILL PASS CLOSE ENOUGH TO KLBF TO BE INCLUDED IN THE TAF UNTIL ABOUT 08Z. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS NORMAN OK
419 AM CDT SAT APR 18 2015 .DISCUSSION... SEVERE THUNDERSTORM POTENTIAL THIS AFTERNOON AND EVENING IS THE MAIN CONCERN. RAIN CHANCES THIS MORNING LOOK TO BE MAINLY CONFINED TO LOCATIONS EAST OF I-35 WHERE MOST LATEST RADAR ECHOES WERE OCCURRING FROM A WEAK IMPULSE ROTATING AROUND A MID/UPPER LOW IN SOUTHERN COLORADO. NO SEVERE STORMS ARE EXPECTED WITH THIS ACTIVITY...JUST SOME LOCALIZED HEAVY RAIN. MOST OF THIS ACTIVITY MAY END BY 8 AM IF THE LATEST HRRR RUNS ARE CORRECT. MOST LOCATIONS WILL REMAIN DRY THIS MORNING. ADDED PATCHY FOG MENTION THROUGH 11 AM THIS MORNING ACROSS PARTS OF WESTERN OKLAHOMA AND WESTERN NORTH TEXAS WHERE SOME PARTIAL CLEARING...ABUNDANT LOW LEVEL MOISTURE...AND LATEST HRRR RUNS FAVOR SOME DEVELOPMENT. DOUBT IT WILL GET TOO WIDESPREAD OR DENSE. THIS AFTERNOON AND EVENING...ISOLATED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE AREA. CAPPING WILL BE RATHER WEAK. WITH MORE SUN COMPARED TO YESTERDAY...THINK CONVECTIVE TEMPERATURES WILL BE REACHED RATHER EASILY IN THE 2 TO 5 PM TIME FRAME. FIRST DEVELOPMENT MAY BE FOCUSED IN WESTERN OKLAHOMA AND WESTERN NORTH TEXAS NEAR A DEVELOPING DRYLINE. WENT NEAR GUIDANCE RAIN CHANCES. EXACTLY WHERE AND WHEN STORMS OCCUR REMAINS TRICKY TODAY AND TONIGHT. IN REGARDS TO SEVERE POTENTIAL THIS AFTERNOON AND EVENING... BELIEVE THERE WILL BE SOME SEVERE STORMS WITH LARGE HAIL AS THE MAIN CONCERN. THE AIR WILL BE MODERATELY UNSTABLE WITH MLCAPE 1500-2500 J/KG. STRONG 0-6 KM SHEAR 30-50 KT SUPPORTS SUPERCELLS AND MULTICELLS. STRONG 0-3 KM SHEAR VALUES 25-45 KT AND VERY COLD MID LEVELS WITH 500 MB TEMPERATURES AROUND -18C COULD SUPPORT VERY LARGE HAIL IN SOME CELLS AS LONG AS CONVECTION IS NOT TOO WIDESPREAD. SOME DAMAGING WINDS MAY OCCUR AS WELL IF STORMS CAN ORGANIZE INTO CLUSTERS AND LINES. TORNADO POTENTIAL APPEARS TO BE LIMITED DUE TO WEAK LOW LEVEL SHEAR...THOUGH NOTICED THE LATEST RAP13 INDICATED STRONGER LOW LEVEL WINDS POSSIBLY DEVELOPING IN SOUTHWESTERN OKLAHOMA IN THE 5 TO 9 PM TIME FRAME WHICH MAY INCREASE THIS POTENTIAL. WILL CLOSELY MONITOR. LOCALLY HEAVY RAINFALL MAY AGAIN OCCUR LATE THIS AFTERNOON AND TONIGHT...THOUGH STORM MOTIONS WILL BE FASTER WHICH MAY LIMIT THE DURATION OF HEAVY RAINFALL IN ONE GIVEN LOCATION. MOST STORMS WILL MOVE INTO EASTERN OKLAHOMA AFTER MIDNIGHT TONIGHT...ALLOWING FOR MOIST AND COOL CONDITIONS. WOULD NOT BE SURPRISED IF SOME FOG FORMED...BUT DID NOT MENTION DUE TO LOW CONFIDENCE. ON SUNDAY...A FEW SHOWERS AND STORMS MAY LINGER MAINLY OVER NORTHERN OKLAHOMA...THOUGH APPEARS THE SEVERE POTENTIAL WILL SHIFT IN FAR EASTERN OKLAHOMA AND POINTS EAST. WITH LINGERING WEAK INSTABILITY AND COLD MID/UPPER LEVELS...A FEW STORMS WITH SMALL HAIL COULD OCCUR. BREEZY CONDITIONS WILL DEVELOP. THERE IS AN OUTSIDE CHANCE WINDS COULD APPROACH ADVISORY CRITERIA WITH GUSTS OVER 40 MPH IN NORTHWEST OKLAHOMA. WENT WITH THE WARMER SIDE OF GUIDANCE TEMPERATURES THINKING SOME SUN WILL OCCUR...ESPECIALLY EARLY IN THE DAY. SUNDAY NIGHT THROUGH FRIDAY...A WET PATTERN MAY CONTINUE WITH RAIN CHANCES REMAINING IN THE FORECAST MOST DAYS. THERE ARE SOME MODEL DISCREPANCIES WITH WEATHER FEATURES...THUS FORECAST CONFIDENCE REMAINS LOW. SOME STRONG TO SEVERE STORMS MAY OCCUR TUESDAY THROUGH FRIDAY WITH NEARBY MOISTURE AND INSTABILITY. MBS && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 77 55 72 45 / 50 70 20 10 HOBART OK 79 50 72 42 / 50 20 10 0 WICHITA FALLS TX 81 53 76 46 / 50 30 10 0 GAGE OK 77 47 66 38 / 40 20 20 10 PONCA CITY OK 75 54 71 41 / 50 70 60 10 DURANT OK 76 58 76 49 / 50 60 20 10 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 25/17
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
141 AM EDT SAT APR 18 2015 .SYNOPSIS... DRIER AND WARMER AIR WILL SPREAD INTO THE REGION THROUGH SATURDAY. A WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA SATURDAY NIGHT INTO SUNDAY...ACCOMPANIED BY ABUNDANT MOISTURE AND MORE RAINFALL. A COLD FRONT WILL CROSS THE AREA ON MONDAY...USHERING IN SEASONABLE TEMPERATURES AND DRY CONDITIONS. && .NEAR TERM /THROUGH TODAY/... AS OF 140 AM...WIDESPREAD PRECIP BEGINNING TO MOVE EAST OF THE AREA. EXPECT THIS TREND TO CONTINUE WITH ONLY SPOTTY LIGHT SHRA FOR THE REST OF THE NITE. OTHERWISE...GOING FCST ON TRACK WITH CLOUDY SKIES AND MILD TEMPS. PATCHY DENSE FOG LIKELY ALONG THE UPPER SAVANNAH RIVER VALLEY AND LITTLE TENNESSEE BASIN...WITH AREAS OF DENSE FOG POSSIBLE. PATCHY DENSE FOG COULD DEVELOP ELSEWHERE AS WELL. MAIN UPDATES WERE FOR CURRENT CONDITIONS. AS OF 1030 PM EDT FRIDAY...WIDESPREAD SHOWERS STILL COVER THE UPSTATE AND PORTIONS OF THE MOUNTAINS...SO CONTINUING CATEGORICAL POPS FOR ANOTHER COUPLE OF HOURS UNTIL THE SHORTWAVE AXIS PUSHES THROUGH STILL LOOKS GOOD. TEMPERATURES ON TRACK FOR THE MOST PART SO ONLY MINOR TWEAKS TO HOURLY TRENDS. AS OF 730 PM EDT FRIDAY...HAVE BUMPED UP POPS ACROSS MOST OF THE AREA THIS EVENING INTO THE OVERNIGHT PERIOD TO ACCOUNT FOR FAIRLY WIDESPREAD LIGHT RAIN/SHOWERS MOVING ACROSS THE AREA...FORCED BY THE RELATIVELY STRONG SHORTWAVE MOVING ACROSS THE SOUTHEAST THIS EVENING. IF THE HRRR IS TO BE BELIEVED...THESE SHOWERS COULD LINGER OVERNIGHT AND PAST SUNRISE...AND WILL EVALUATE FURTHER FOR THE LATE EVENING UPDATE. BEST MOISTURE REMAINS ACROSS THE UPSTATE AND NORTHEAST GEORGIA BUT STILL SEEING SOME LIGHT RAIN ACROSS THE MOUNTAINS AND FOOTHILLS. STILL SEEING SOME SBCAPE VALUES HOLDING ON ACROSS THE PIEDMONT BUT THESE SHOULD BEGIN DROPPING RAPIDLY WITH SUNSET...SO HAVE PULLED BACK ON THUNDER WORDING THIS EVENING AND OVERNIGHT. OTHER GRIDS IN GOOD SHAPE FOR THE MOST PART...WITH ONLY MINOR TWEAKS TO ACCOUNT FOR HOURLY TRENDS. AS OF 430 PM EDT FRIDAY...VERY LITTLE CHANGE TO PREVIOUS THINKING FOR THE NEAR TERM. PRECIPITATION BEGINNING TO OVERSPREAD WESTERN AND SOUTHWESTERN ZONES AS EXPECTED. NEW GUIDANCE BEGINNING TO PULL BACK A LITTLE ON CONVECTIVE POTENTIAL...WITH INCREASING CLOUD COVER AND MOISTENING ATMOSPHERE WHAT LITTLE SBCAPE WAS BEGINNING TO CREEP INTO THE MESOANALYSES OVER THE PAST COUPLE OF HOURS IS ONCE AGAIN FALLING OFF. LOOKING AT HI-RES REFLECTIVITY FORECASTS...DEFINITELY STARTING TO LOOK LIKE MORE STRATIFORM RAIN OR SHOWERS WITH THE POSSIBILITY OF EMBEDDED THUNDER. HAVE LEFT WEATHER WORDING AS IS FOR NOW SINCE CURRENTLY ADVERTISED THUNDER IS CHANCE AT BEST...BUT WILL REEVALUATE MORE THOROUGHLY FOR NEXT NEAR-TERM UPDATE. ONLY MINOR TWEAKS TO TEMPS AND DEWPOINTS TO UPDATE TRENDS. AS OF 245 PM EDT FRIDAY...THE SYNOPTIC PATTERN HAS NOT CHANGED ALL THAT MUCH FROM YESTERDAY...OR DAYS PAST FOR THAT MATTER. IT STILL FEATURES ROTATING CLOSE UPPER LOW OVER THE FOUR CORNERS WHILE DEEP SOUTHWEST WAA PREVAILS ACROSS THE SOUTHEAST UNITED STATES. AT THE SURFACE...SPRINGTIME WEDGE STARTING TO ERODE AS EXPECTED THIS AFTERNOON AS WINDS HAVE VEERED SOUTHERLY ACROSS NORTHEAST GA AND THE UPSTATE...ALONG WITH A FEW LOCATIONS OVER THE NC PIEDMONT. FURTHERMORE...H5 SHORT WAVE AND ASSOCIATED VORTICITY MAXIMA CONTINUES TO SLIDE EAST ACROSS THE DEEP SOUTH WITH A BROAD AREA OF PRECIPITATION ACCOMPANYING. LATEST SPC MESO ANALYSIS NOT ALL THAT IMPRESSIVE AS INSTABILITY REMAINS NEARLY NONEXISTENT ACROSS THE FCST AREA. MODELS FAVOR IMPROVING LAPSE RATES WITH HEATING THIS AFTERNOON...HOWEVER STILL SKEPTICAL AS PRECIP SHIELD AND ASSOCIATED LOW OVERCAST SKY COVER WILL LIMIT HEATING. NEVERTHELESS...THE FCST DOES FEATURE INCREASING POPS THROUGH THE AFTERNOON/EVENING HOURS WITH CHANCES FOR THUNDER MENTIONED...AND WILL CONTINUE WITH SUCH IN THE HWO. POPS WILL LOWER AFTER MIDNIGHT AS THE PRIMARY UPPER WAVE EJECTS TO THE EAST...AND A WEAK/DRY BACK DOOR FRONT SLIDES SOUTHWARD ACROSS THE REGION. HELD ON TO TOKEN SLIGHT/CHANCE POPS THROUGH MORNING TO ACCOUNT FOR ANY RESIDUAL SHRA ALONG THE BOUNDARY. LATEST SOUNDINGS DO NOT SUGGEST AS MUCH MID DRYING AS THE PREVIOUS RUN...THEREFORE NOT ALL THAT CONFIDENT IN AREAS OF DENSE FOG OVERNIGHT. THAT SAID...WOULDNT BE SURPRISED TO SEE ISOLATED CASES OF SUCH ACROSS THE NC PIEDMONT/FOOTHILLS JUST AHEAD OF THE INTRUDING BOUNDARY WHEN WINDS ARE CALMEST AND THE PBL IS DECOUPLED. SATURDAY WILL BE HIGHLIGHTED BY DECREASING CLOUDINESS AS DOWNSLOPING FLOW PREVAILS AMONGST INCREASING HEIGHTS ALOFT AS AXIS OF SHORTWAVE RIDGE SHIFTS OVERHEAD. POPS WILL INCREASE YET AGAIN THROUGH THE DAY AS FCST SOUNDINGS INDICATE MODEST DESTABILIZATION WITH HEATING. HOWEVER EXPECTING UPPER RIDGING TO PROVIDE SOME SUBSIDENCE THEREFORE KEPT POPS AT OR BELOW CHANCE LEVELS THROUGH THE DAY. TEMPERATURES ON SATURDAY WILL DEPEND HIGHLY ON HOW SOON THE SKY COVER SCT OUT. TOOK A MIDDLE OF THE ROAD APPROACH AS IT PERTAINS TO GUIDANCE...WITH THE FCST FEATURING HIGHS 3-5 DEGREES ABOVE NORMAL. && .SHORT TERM /TONIGHT THROUGH MONDAY/... AS OF 200 PM FRIDAY...TWO AREAS OF CONCERN TO DEAL WITH IN THE SHORT TERM. THE FIRST WILL BE A PERIOD OF HEAVY RAIN ON SUNDAY AND THEN A RISK OF SEVERE STORMS ON MONDAY. THE UPPER RIDGE OVER THE SOUTHEAST U.S. WILL TRANSLATE EASTWARD SATURDAY NIGHT AS THE UPPER LOW THAT HAS BEEN OVER THE 4-CORNERS BEGINS TO MOVE EAST THANKS TO A DIGGING TROUGH MOVING SE OUT OF THE CANADIAN PRAIRE. A SHORT WAVE OUT AHEAD OF THE UPPER LOW WILL MOVE NE FROM THE GULF COAST AND ACROSS THE WESTERN CAROLIANS AND NE GA ON SUNDAY. AT THE SURFACE...A WARM FRONT WILL APPROACH FROM THE SW ON SUNDAY. ALL OF THIS WILL RESULT IN ALL TYPES OF FORCING ACROSS THE REGION ON SUNDAY. PWATS WILL BE IN THE 1.5-1.7" RANGE WITH A 35-45 KT SELY 850 MB JET INTO THE BLUE RIDGE. WILL RAMP POPS UP QUICKLY TO CATEGORICAL FROM WEST TO EAST BY MIDDAY SUNDAY...THEN DECREASE RAPIDLY FROM WEST TO EAST LATE SUNDAY AS THE AXIS OF DEEP MOISTURE AND FORCING SHIFT EAST. HEAVY RAIN LOOKS TO BE A GOOD BET...BUT THE RELATIVELY QUICK MOVEMENT OF THE SYSTEM SHOULD PRECLUDE ANY SERIOUS HYDRO ISSUES. BLENDING THE MODEL CONSENSUS AND WPC QPF GUIDANCE... RESULTS IN GENERALLY 1.5"-2.0" FROM LATE SATURDAY NIGHT INTO SUNDAY NIGHT. THE HIGHEST AMOUNTS AS USUAL ARE EXPECTED TO BE NEAR THE BLUE RIDGE ESCARPMENT WHERE 2-3" OF RAIN CAN BE EXPECTED. THESE VALUES ARE UNDER THE 12 TO 24 HOUR FFG. THERE MAY BE SOME LOCALIZED FLOODING BUT WIDESPREAD FLOODING IS UNLIKELY. HOWEVER...WILL CONTINUE TO MENTION HEAVY RAIN IN THE HWO. AN IN SITU WEDGE WILL RESULT IN COOL TEMPS ON SUNDAY AND WILL THEREFORE TREND TOWARD CONSRAW GUIDANCE TEMPS. SOME DEGREE OF CLEARING SHOULD OCCUR SUNDAY NIGHT AS THE AXIS OF DEEP MOISTURE SHIFTS NE AND A DOWNSLOPE WIND COMPONENT THROUGH THE COLUMN DEVLOPS. ON MONDAY...A COLD FRONT WILL MOVE ACROSS THE REGION FROM WEST TO EAST. BOTH THE NAM AND GFS INDICATE THAT THE ATMOSPHERE WILL DESTABLIZE BY AFTERNOON WITH CAPES MOST LIKELY INCREASING TO BETWEEN 1000 AND 1500 J/KG PER GFS AND ECM. ALSO...0-6KM SHEAR INCREASES TO ABOUT 40KT. THIS MAY SUPPORT SOME ORGANIZION TO THE CONVECTION AS THE COLD FRONT MOVES THROUGH. THE 12Z NAM MODEL REFLECTIVY SUGGESTS THAT A BROKEN LINE OF CONVECTION WILL ACCOMPANY THE FRONT ACROSS THE AREA ON MONDAY WITH A FEW SEVERE STORMS POSSIBLE. WITH THE AREA SOLIDLY IN THE WARM SECTOR ON MONDAY...MAX TEMPS ARE EXPECTED TO BE ABOUT 5 DEGREES ABOVE CLIMO. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 245 PM FRIDAY...MONDAY NIGHT...SFC HIGH PRESSURE WILL BUILD OVER THE FORECAST AREA IN THE WAKE OF A PASSING COLD FRONT. 12Z GFS INDICATES THAT H85 TEMPERATURES WILL COOL BY 5 C FROM 0Z TO 12Z TUESDAY...A LITTLE LESS COOLING ON THE ECMWF. USING A BLEND OF GUIDANCE...I WILL FORECAST LOW TEMPERATURES FROM THE UPPER 40S WITHIN THE MTN VALLEYS TO MID 50S EAST. ON TUESDAY...BROAD HIGH PRESSURE WILL REMAIN ACROSS THE CWA. THE REGION SHOULD SEE MOSTLY SUNNY CONDITIONS WITH A LIGHT SOUTHWEST WIND. TEMPERATURES SHOULD RESPOND TO THE LATE APRIL SUN AND WEAK DOWNSLOPING...FORECAST TUES HIGHS SLIGHTLY ABOVE NORMAL. WEDNESDAY THROUGH FRIDAY...THE GFS AND ECMWF GENERALLY AGREE THAT A LARGE CLOSED MID LEVEL LOW WILL REMAIN ACROSS THE NORTHEAST AND EASTERN CANADA...AS A RIDGE LINGERS OVER THE SOUTHERN PLAINS. THE HEIGHTS ACROSS THE CWA WILL LIKELY REMAIN NW TO SE THROUGH THE PERIOD. THE MODELS ARE IN LESS AGREEMENT WITH THE PLACEMENT AND TIMING OF SFC FEATURES...PRIMARILY WEAK FRONTS AND PRESSURE CENTERS. I AM MORE CONFIDENT TIMING MID LEVEL FEATURES WITHIN THE NW FLOW ACROSS THE SOUTHERN APPALACHIANS...I WILL FAVOR THE ECMWF. OVERALL...I WILL KEEP CONDITIONS DRY ON WED...BUT MOISTURE WILL INCREASE THROUGH THE DAY. A SHORT SERIES OF MID LEVEL S/W ARE FORECAST TO RIPPLE ACROSS THE CWA THURSDAY THROUGH FRIDAY. TEMPERATURES SHOULD RANGE CLOSE TO NORMAL WITH AFTERNOON DEWPOINTS ONLY IN THE 40S. GIVEN THE TRACK OF THE MID LEVEL DISTURBANCES AND WEAK DIURNAL INSTABILITY...I WILL INDICATE ONLY SCHC POPS ACROSS THE MTNS ON THURSDAY. FORECAST SOUNDINGS SHOW GREATER INSTABILITY FRIDAY AFTERNOON...FROM THE MTNS TO THE PIEDMONT. THE COMBINATION OF THE PASSING DISTURBANCE AND INSTABILITY SHOULD SUPPORT SCT COVERAGE ACROSS THE MTNS AND ISO EAST. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AT KCLT...CANNOT RULE OUT A BRIEF MVFR VSBY OR CIG AS SHRA MOVE ACROSS THE AIR FIELD EARLY THIS MORNING. HOWEVER...DO EXPECT CONDITIONS TO FALL TO MVFR THEN IFR TOWARD DAYBREAK AFTER THE PRECIP ENDS. EXPECT LOW VFR BY NOON OR SO AS FORCING ENDS AND LOW LEVEL MOISTURE MIXES OUT. MVFR COULD RETURN BY THE END OF THE PERIOD...BUT MORE LIKELY TOWARD THE END OF THE NEXT TAF ISSUANCE. LIGHT NORTH OR CALM WIND EARLY THIS MORNING BECOMES LIGHT NE...THEN ENE THRU THE DAY. ELSEWHERE...PRECIP WILL SOON MOVE EAST OF THE AREA AND CONDITIONS WILL FALL TO IFR BEFORE DAYBREAK. IN FACT...LIFR LIKELY...LIKE THE CURRENT CONDITIONS AT KAND. EXPECT A SLOW IMPROVEMENT TO LOW VFR THRU THE MORNING. MVFR AND PRECIP MOVE BACK IN FROM THE WEST TONIGHT. CALM WIND BECOMES NE THIS MORNING...THEN ENE TONIGHT. KAVL WILL SEE NLY WIND BECOMING SLY TODAY...REMAINING THERE TONIGHT. OUTLOOK...DEEPER MOISTURE WILL RETURN ALONG A WARM FRONT THROUGH SUNDAY...WITH HEAVY RAINFALL AND WIDESPREAD RESTRICTIONS LIKELY ONCE AGAIN. THUNDERSTORMS WILL THEN BE POSSIBLE THROUGH MONDAY AS A COLD FRONT REACHES THE AREA FROM THE WEST. CONFIDENCE TABLE... 05-11Z 11-17Z 17-23Z 23-00Z KCLT MED 66% MED 62% LOW 57% HIGH 100% KGSP MED 75% MED 62% MED 64% HIGH 100% KAVL HIGH 100% HIGH 87% LOW 59% HIGH 100% KHKY HIGH 100% HIGH 87% MED 66% HIGH 100% KGMU HIGH 91% MED 69% MED 71% HIGH 100% KAND MED 75% MED 75% LOW 52% HIGH 90% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...CSH NEAR TERM...CDG/RWH/TDP SHORT TERM...LG LONG TERM...NED AVIATION...RWH
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
420 AM CDT Sat Apr 18 2015 .SHORT TERM... (Today and Tonight) There is a threat for severe thunderstorms across the eastern half of West Central Texas today as an upper level trough associated with the upper low near the Four Corners moves across the region. The main threats will be large hail and damaging winds. SPC has placed much of the area east of the dryline in a slight risk for severe thunderstorms today. Latest radar is showing showers developing across the mountains in northern Mexico, south of Sanderson, in association with the next approaching shortwave as can be seen on water vapor satellite imagery. This could bring a round of showers and thunderstorms to West Central Texas this morning before the main upper trough moves across later this afternoon. The dryline is forecast to move east today as the RUC model progs this front from Haskell to just east of San Angelo to Sonora by early evening. This dryline should trigger scattered thunderstorms this afternoon as the following ingredients come together: dewpoints ranging from the upper 50s to the lower 60s, moderate 0-6km shear, MU CAPE Values 1500-2000 J/KG, a weak capping inversion, approaching upper trough and a right rear entrance region of the southern stream upper level jet flowing across the area. These parameters should set the stage for the development of a few supercells today, resulting in large hail and damaging winds. These storms may continue into the early evening hours before dissipating. Highest Pops were placed across the Northwest Hill Country extending north to Brownwood. Went closer to the warmer MAV MOS for temps as the dry warm air invades the western part of the region today. 26 .LONG TERM... (Sunday through Friday) Cold front will move through Sunday. Dry southwest to west winds ahead of the front will not only preclude rain chances, but also give a boost to temperatures, being downslope compression. Still, cold advection will bring cooler temperatures Sunday, with highs in the 70s. Isolated dryline thunderstorms possible mid and late week. West Central Texas will be under a broad upper ridge, so widespread showers or thunderstorms not expected. Could see a few highs approach 90s, especially Wednesday and Thursday. && .PRELIMINARY POINT TEMPS/POPS... Abilene 82 55 79 49 72 / 30 20 5 5 5 San Angelo 84 54 82 50 75 / 30 10 5 5 5 Junction 82 56 85 52 75 / 50 30 5 5 5 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 26/04
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
415 AM CDT SAT APR 18 2015 .DISCUSSION... THE UPPER LOW THAT HAS BEEN PARKED OVER THE FOUR CORNERS IS BEGINNING TO DISLODGE...AND BY THIS TIME SUNDAY MORNING IT WILL BE OVER THE HIGH PLAINS NEAR THE COLORADO/KANSAS BORDER. THIS WILL STEADILY VEER THE 700MB FLOW ACROSS WEST TEXAS TODAY...HELPING TO NUDGE THE DRYLINE FARTHER EAST THAN IN RECENT DAYS. ALTHOUGH WITHIN THE FIRST 24 HOURS OF THE LATEST GUIDANCE...OPERATIONAL SOLUTIONS VARY WIDELY ON THE LATE AFTERNOON POSITION. ALTHOUGH THE NAM IS AMONG THE FARTHEST WEST...WHICH IS UNUSUAL IN THIS SCENARIO...THE CONSENSUS AMONG THE MESOSCALE GUIDANCE IS FOR THE BOUNDARY TO REACH A VERNON-SAN ANGELO LINE NEAR PEAK HEATING. OUR FORECAST WILL FAVOR THIS POSITION. BASED ON THE MID-LEVEL FLOW... THERE SHOULD BE A BULGE NEAR THE RED RIVER. THE RAP AND TTU WRF SHOW THIS CLEARLY...ADDING TO THE CONFIDENCE IN THEIR EVOLUTION OF THE BOUNDARY TODAY. THE ATMOSPHERE ACROSS NORTH TEXAS HAS BEEN WELL WORKED OVER. THIS STABILITY...COUPLED WITH SUBSIDENCE IN THE WAKE OF A DEPARTING DISTURBANCE...SHOULD PRECLUDE MUCH ADDITIONAL PRECIPITATION THIS MORNING. WEAK LOW-LEVEL FLOW WILL RESULT IN NEGLIGIBLE MOIST ADVECTION TODAY...AND DESTABILIZATION THIS AFTERNOON WILL BE PRIMARILY GOVERNED BY SURFACE HEATING. ALTHOUGH THE I-35 CORRIDOR WILL BE SLOW TO CLEAR TODAY...WESTERN NORTH TEXAS WILL SEE SUFFICIENT SUNSHINE. EXPECT THUNDERSTORMS TO DEVELOP ALONG THE DRYLINE MID TO LATE AFTERNOON. THOUGH RELATIVELY WEAK...THE STEERING FLOW ALOFT SHOULD GUIDE THE ACTIVITY EAST THROUGH NORTH TEXAS THIS EVENING. EVEN THOUGH THE SURFACE LAYER WILL BE STEADILY STABILIZING AT THAT TIME...THE COLD POOL ASSOCIATED WITH AN ORGANIZED MCS SHOULD PROLONG THE LIFESPAN OF ITS UPDRAFTS. THIS WILL MAINTAIN A HAIL THREAT WELL INTO THE EVENING. THIS IS NOT THE TYPICAL SETUP FOR A SQUALL LINE...BUT A WELL ORGANIZED COMPLEX COULD POSE A WIND THREAT AS WELL. THE SPEED SHOULD BE SUFFICIENT TO AVOID SIGNIFICANT FLOODING CONCERNS IN MOST AREAS...BUT WHERE HEAVY RAIN HAS FALLEN RECENTLY...ADDITIONAL RAINFALL COULD REAGGRAVATE FLOODING ISSUES. AS THE UPPER LOW EJECTS THROUGH THE CENTRAL PLAINS...IT WILL SURGE A COLD FRONT THROUGH THE REGION. WITH WIDESPREAD ACTIVITY THIS EVENING...LARGE-SCALE SUBSIDENCE INVADING...AND VEERING LOW-LEVEL FLOW EARLY SUNDAY...THE ATMOSPHERE SHOULD BE UNABLE TO PRODUCE ANY FRONTAL PRECIPITATION. THE EXCEPTION WOULD BE EAST TEXAS...WHERE THE MOISTURE PROFILE WILL BE MORE FAVORABLE...AND THE FRONT WILL ARRIVE DURING THE WARM AFTERNOON HOURS. ABUNDANT APRIL SUNSHINE AND A PRONOUNCED DOWNSLOPE WIND SHOULD OFFSET ANY COLD ADVECTION BEHIND THE FRONT...AND TEMPERATURES SHOULD REACH THE 80S IN MANY AREAS SUNDAY AFTERNOON. THE COOL AIR WILL ARRIVE SUNDAY NIGHT... AND RURAL AREAS IN THE NORTHERN HALF OF THE CWA WILL LIKELY DIP INTO THE 40S MONDAY AND TUESDAY MORNING. ZONAL FLOW WILL PREVAIL MUCH OF THE UPCOMING WEEK. THE NEXT WAVE EMBEDDED IN THIS WESTERLY FLOW WILL ARRIVE AROUND TUESDAY...BUT AT THAT TIME...BOUNDARY LAYER MOISTURE MAY NOT HAVE BEEN ABLE TO SUFFICIENTLY RECOVER. ADDITIONAL RIPPLES WILL FOLLOW...MAINTAINING RAIN CHANCES. HOWEVER...POPS ARE NOTHING MORE THAN CLIMATOLOGY. EXTENDED GUIDANCE IS IN REMARKABLY GOOD AGREEMENT WITH UNSEASONABLE STRONG SHORTWAVE RIDGING AS THE NEXT UPPER LOW ENTERS THE DESERT SOUTHWEST. GFS MOS TEMPS FOR THURSDAY AND FRIDAY ARE NEAR 90 DEGREES. WITH PERFECT PROG 850MB TEMPS AROUND 20C...THIS IS NOT OUT OF THE QUESTION. A BIT CONCERNED THAT CLOUD COVER MAY PUT A DAMPER ON THE SPRING FEVER...AND FOR NOW...WILL KEEP TEMPERATURES CLOSER TO CLIMATOLOGY. 25 && .AVIATION... /ISSUED 635 PM CDT FRI APR 17 2015/ FOR THE 00Z TAFS...TRACKING THE NORTH/SOUTH ORIENTED LINE OF THUNDERSTORMS MOVING EAST TOWARDS THE DFW METROPLEX IS THE PRIMARY FORECAST CONCERN. THE LINE OF STORMS JUST WEST OF TARRANT COUNTY HAS BEEN LOSING INTENSITY FOR THE MOST PART...AND AS A RESULT HAS BEEN CONSISTENTLY SLOWLY DOWN WITH REGARDS TO ITS EASTERLY PROGRESS. THE MOST INTENSE PART OF THE LINE IS LOCATED OVER FAR SOUTHWESTERN TARRANT COUNTY...MOVING EAST NOW AT ABOUT 20 MPH. FOR THE MOST PART THIS LINE OF STORMS WILL BE CAPABLE OF PRODUCING 20 TO 30 MPH WIND GUSTS...HEAVY RAINFALL...AND FREQUENT LIGHTNING AS IT MOVES OVER AREA TAF SITES. THE MORE INTENSE LINE OF STORMS OVER FAR SOUTHERN TARRANT COUNTY WILL BE CAPABLE OF PRODUCING WIND GUSTS OF 40 TO 45 MPH AS WELL AS HEAVY RAINFALL AND FREQUENT LIGHTNING. THIS MORE INTENSE LINE OF STORMS APPEARS ON TRACK TO MOVE OVER KGKY AIRPORT...REMAINING JUST SOUTH OF KFTW...KDFW...KAFW...AND KDAL AIRPORTS. WILL LIKELY HAVE TO KEEP AMENDING THE TAFS FOR TIMING CONSIDERATIONS AS THE STORMS ROLL ACROSS THE DFW AREA. BEHIND THE MAIN LINE OF STORMS...LIGHT RAIN SHOWERS ARE EXPECTED TO PERSIST FOR A COUPLE OF HOURS BEFORE ALL PRECIPITATION ENDS ACROSS THE DFW AREA. OTHER THAN STORMS...IFR CIGS ARE EXPECTED TO BUILD OVER NORTH AND CENTRAL TEXAS FROM THE SOUTH EARLY TOMORROW MORNING. DID NOT SEE ANY REASON TO CHANGE THE TIMING OF THE ONSET OF IFR CIGS FROM THE PREVIOUS FORECAST...BUT MAY NEED TO ADJUST THE TIMING ONCE STORMS HAVE DISSIPATED...ALLOWING FOR AN EVALUATION OF WHERE OUTFLOW BOUNDARIES END UP. DID NOT HAVE ENOUGH CONFIDENCE IN THE TIMING OF STORMS ON SATURDAY TO INCLUDE THEM IN THE TAFS AT THIS TIME. STORMS MAY ONCE AGAIN THREATEN AREA TAF SITES TOMORROW AFTERNOON OR EVENING. CAVANAUGH && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 79 60 80 53 73 / 40 50 10 5 5 WACO, TX 80 60 83 53 75 / 40 50 10 5 5 PARIS, TX 75 58 77 50 70 / 50 40 20 5 0 DENTON, TX 77 57 79 49 72 / 40 50 10 5 5 MCKINNEY, TX 78 58 79 51 73 / 40 50 10 5 0 DALLAS, TX 80 62 81 54 74 / 40 50 10 5 5 TERRELL, TX 78 60 80 52 74 / 40 50 10 5 5 CORSICANA, TX 79 61 82 52 75 / 40 50 20 5 5 TEMPLE, TX 79 60 84 53 74 / 40 50 10 5 5 MINERAL WELLS, TX 81 55 79 48 74 / 40 50 10 5 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/25
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
411 AM CDT Sat Apr 18 2015 .SHORT TERM... (Today and Tonight) There is a threat for severe thunderstorms across the eastern half of West Central Texas today as an upper level trough associated with the upper low near the Four Corners moves across the region. The main threats will be large hail and damaging winds. SPC has placed much of the area east of the dryline in a slight risk for severe thunderstorms today. The dryline is forecast to move east today as the RUC model progs this front from Haskell to just east of San Angelo to Sonora by early evening. This dryline should trigger scattered thunderstorms this afternoon as the following ingredients come together: dewpoints ranging from the upper 50s to the lower 60s, moderate 0-6km shear, MU CAPE Values 1500-2000 J/KG, a weak capping inversion, and a right rear entrance region of the southern stream upper level jet flowing across the area. These parameters should set the stage for the development of a few supercells today, resulting in large hail and damaging winds. These storms may continue into the early evening hours before dissipating. Highest Pops were placed across the Northwest Hill Country extending north to Brownwood. Went closer to the warmer MAV MOS for temps as the dry warm air invades the western part of the region today. 26 .LONG TERM... (Sunday through Friday) Cold front will move through Sunday. Dry southwest to west winds ahead of the front will not only preclude rain chances, but also give a boost to temperatures, being downslope compression. Still, cold advection will bring cooler temperatures Sunday, with highs in the 70s. Isolated dryline thunderstorms possible mid and late week. West Central Texas will be under a broad upper ridge, so widespread showers or thunderstorms not expected. Could see a few highs approach 90s, especially Wednesday and Thursday. && .PRELIMINARY POINT TEMPS/POPS... Abilene 82 55 79 49 72 / 30 20 5 5 5 San Angelo 84 54 82 50 75 / 30 10 5 5 5 Junction 82 56 85 52 75 / 50 30 5 5 5 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 26/04
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
401 AM CDT SAT APR 18 2015 .SHORT TERM (TODAY THROUGH SUNDAY)... AN UPPER LEVEL STORM SYSTEM IS CENTERED ACROSS COLORADO EARLY THIS MORNING. THIS SYSTEM IS FORECAST TO MOVE TO THE NORTHEAST AND THEN EAST THROUGH THE WEEKEND AND BECOMES AN OPEN WAVE LATE SUNDAY AFTERNOON. SEVERAL SHORT WAVES ASSOCIATED WITH THE UPPER LEVEL LOW ARE ANTICIPATED TO PUSH ACROSS THE AREA FOR THE NEXT 12 TO 18 HOURS AND ENHANCE STORM DEVELOPMENT LATE THIS MORNING THROUGH THE EVENING HOURS. AT LOWER LEVELS...A PRE-FRONTAL TROUGH/DRY-LINE WILL SERVE AS THE MAIN FOCUS AS STORMS FORM IN THE MOIST AND WARM SECTOR. BY THIS AFTERNOON...DEWPOINT TEMPERATURES ARE FORECAST TO REACH THE MID TO UPPER 60S WITH AREA SOUNDINGS SUGGESTING ML CAPES OF 1500 TO 2500J/KG AND LI RANGING FROM -5 TO -10 FOR LARGE TO EXTREME INSTABILITY. THEREFORE...ANY STORM THAT DOES DEVELOP HAS THE POTENTIAL TO BECOME STRONG OR SEVERE. PER SPC DAY 1 CONVECTIVE OUTLOOK...ALL OF SOUTH CENTRAL TEXAS WITH THE EXCEPTION OF THE NORTHWEST PORTION OF VAL VERDE COUNTY...IS UNDER A SLIGHT RISK OF SEVERE THUNDERSTORMS. HIRES SOLUTIONS ARE HAVING DIFFICULTIES ON TIMING AND AREAS OF STORM DEVELOPMENT INITIALLY. THE HRRR STARTS CONVECTION ACROSS THE SOUTHERN COUNTIES AS AN MCS DEVELOPS ACROSS THE COASTAL PLAINS AND MOVE TO THE EAST. THE TEXAS TECH IS MORE AGGRESSIVE ON FORMING STORMS AHEAD OF THE DRY-LINE AS IT PUSHES TO THE EAST AND OVER THE EDWARDS PLATEAU/HILL COUNTRY AREA. THE HRRR DOES DEVELOP CONVECTION AHEAD OF THE DRY-LINE THIS AFTERNOON BUT NOWHERE NEAR TEXAS TECH MODEL. THEREFORE...THE SHORT-TERM/FIRST PERIOD CONSISTS ON A BLEND OF THE HRRR/TEXAS TECH SOLUTIONS. BY LATER THIS EVENING...MID LEVEL WESTERLY WILL TAKE OVER AS THE UPPER LEVEL LOW PUSHES TO THE EAST...MARKING THE END OF RAIN CHANCES THROUGH MONDAY. WITH A WESTERLY FLOW IN PLACE FOR SUNDAY...EXPECT A NICE WARMUP WITH HIGHS IN THE UPPER 80S AND LOWER 90S. CAN NOT RULE OUT AN ISOLATED STORMS ACROSS THE FAR EASTERN COUNTIES SUNDAY AFTERNOON AS LINGERING INSTABILITY REMAINS. A BACK DOOR COLD FRONT WILL PUSH ACROSS THE AREA SUNDAY EVENING TO COOL THE OVERNIGHT TEMPS INTO THE 50S AREAWIDE. && .LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)... A CLEAR NIGHT IS IN STORE FOR SUNDAY NIGHT WITH NORTHERLY WINDS AND COOL TEMPERATURES FOLLOWED BY A PARTLY CLOUDY DAY ON MONDAY. SOUTHERLY FLOW RETURNS TUESDAY AS WELL AS THE RAIN CHANCES FOR SOUTH CENTRAL TEXAS. SEVERAL SHORT WAVES ARE EXPECTED TO PASS BY AND TRIGGER SHOWERS AND STORMS THROUGH FRIDAY. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 81 61 89 57 76 / 40 40 - - - AUSTIN BERGSTROM INTL AIRPORT 81 60 87 55 76 / 50 40 - - - NEW BRAUNFELS MUNI AIRPORT 81 60 87 56 76 / 50 30 0 - - BURNET MUNI AIRPORT 79 57 87 53 74 / 40 40 - - - DEL RIO INTL AIRPORT 86 59 90 59 79 / 30 10 0 - 10 GEORGETOWN MUNI AIRPORT 79 59 87 54 74 / 40 40 10 - - HONDO MUNI AIRPORT 82 59 88 57 78 / 40 20 0 - - SAN MARCOS MUNI AIRPORT 81 61 86 56 75 / 50 40 0 - - LA GRANGE - FAYETTE REGIONAL 80 63 86 57 75 / 50 40 20 10 10 SAN ANTONIO INTL AIRPORT 81 61 88 58 77 / 40 30 0 - - STINSON MUNI AIRPORT 82 61 88 59 77 / 40 20 - - - && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...17 SYNOPTIC/GRIDS...29
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1147 PM CDT FRI APR 17 2015 .UPDATE... SOME MINOR CHANGES TO THE FORECAST INCLUDE INSERTING A MENTION OF FOG AND INCREASING MINIMUM TEMPERATURES FOR TONIGHT. THE DRYLINE HAS MOVED FARTHER WEST THAN MODELS FORECAST BRINGING IN MOIST AIR ON THE CAPROCK. MODELS HAVE TRENDED TOWARDS DEVELOPING FOG IN THE MOIST AIR THROUGH MID MORNING. FURTHERMORE...T/TD SPREADS OFF THE CAPROCK WERE ALREADY RUNNING BETWEEN 1-2 DEGREES. IT IS STILL NEBULOUS ON WHETHER AREAS ON THE CAPROCK WILL SEE FOG OR NOT. THE DRYLINE RECENTLY ENCOUNTERED A WESTWARD MOVING BOUNDARY WHICH HAS GREATLY SLOWED THE PROGRESSION OF THE DRYLINE. AT SOME POINT...THE DRYLINE WILL LIKELY BEGIN MOVING EAST. OVERNIGHT TEMPERATURES WERE GENERALLY RAISED ON EASTERN PORTIONS OF THE CAPROCK WHERE THIS MOISTURE HAS INVADED. && .AVIATION... VERY MOIST AIR NEAR THE SURFACE WILL LIKELY BRING FOG INTO THE KCDS TERMINAL EARLY SATURDAY MORNING. IT REMAINS UNCLEAR ON WHETHER FOG WILL MAKE IT INTO KLBB OR KPVW. A DRYLINE BOUNDARY IS CLOSE TO BOTH TERMINALS WHICH MAKES IT UNCERTAIN ON WHETHER THE LOW LEVEL MOISTURE WILL STAY IN THE VICINITY OF EITHER TERMINAL. IF MOISTURE DOES HANG ON...THEN FOG AND LOW CIGS WILL BE POSSIBLE AT KLBB AND KPVW. BREEZY WINDS WILL DEVELOP OUT OF THE SOUTHWEST DURING THE AFTERNOON AT ALL TAF SITES. && PREV DISCUSSION... /ISSUED 321 PM CDT FRI APR 17 2015/ SHORT TERM... DRYLINE AT 19Z EXTENDED FROM JUST WEST OF SILVERTON SOUTH TO WHITE RIVER LAKE AND NEAR LAKE ALAN HENRY. THIS BOUNDARY HAS BEEN FORCED WEST ALL DAY BY CONVECTIVE OUTFLOWS FARTHER EAST AND RECENT RUNS OF THE RUC HAVE THE DRYLINE ARRIVING ALONG INTERSTATE 27 BY THIS EVENING...PERHAPS MUCH SOONER. INSTABILITY-WISE...A NARROW AXIS OF SBCAPE AROUND 1000 J/KG MAY FULFILL SOME TSTORMS ALONG AND EAST OF THE DRYLINE THROUGH THE EVENING...BUT VISUAL TRENDS OF TOWERING AND MODERATE CU SUGGEST DEEPER ASCENT IS LACKING. WATER VAPOR IMAGERY INDICATE THIS AREA IS BATTLING SUBSIDENCE ALOFT DUE TO AN AXIS OF PERSISTENT DEEP CONVECTION 60-100 MILES FARTHER EAST. BECAUSE OF THIS AND LIMITED NWP SUPPORT...POPS HAVE BEEN SCALED BACK TO SLIGHT CHANCE FOR MOST AREAS OFF THE CAPROCK. AS THE FOUR CORNERS LOW BEGINS LIFTING NORTHEAST TONIGHT...LOWER TROPOSPHERIC WINDS WILL VEER MORE WESTERLY ACROSS THE WESTERN HALF OF THE CWA AND HELP TO NUDGE THE DRYLINE EASTWARD BEFORE DAYBREAK SAT. MODELS AGREE THE DRYLINE WILL MIX OUT OF OUR EASTERN ZONES BY MIDDAY AHEAD OF BREEZY SW WINDS...BUT ANY DISRUPTION TO THIS SUCH AS WE SAW TODAY WITH CONVECTIVE OUTFLOWS COULD SUPPORT A MORE WESTERLY DRYLINE LOCATION AND NECESSITATE MODIFICATIONS TO OUR DRY FORECAST FOR SATURDAY. WHEREVER THE DRYLINE ENDS UP...DEEP CONVECTION SHOULD EASILY UNFOLD BY SAT AFTN UNDER WEAK INHIBITION...STRONGER CYCLONIC FLOW AND A FAVORABLE MID-LEVEL COLD POCKET OF -20C AT 500MB. LONG TERM... COLD FRONT PROGGED TO MOVE THROUGH THE FCST AREA SUNDAY MORNING WITH ENOUGH COLD ADVECTION TO RESULT IN HIGHS MAINLY UPPER 60S AND LOWER 70S WHILE ALSO SCOURING LOW LEVEL MOISTURE OUT OF THE FCST AREA. MAY SEE SOME CONVECTION ATTEMPT TO DEVELOP ON THE HIGH TERRAIN OF NRN NM/SRN COLO AND BE DRIVEN TO THE SE ON NWLY UPPER FLOW...BUT WITH DRY LOW LEVELS WOULD EXPECT IT TO HAVE A HARD TIME GETTING THIS FAR TO THE SE. SITUATION CHANGES SOME MONDAY WHEN SOUTH AND SE WINDS BEGIN TO BRING MOISTURE BACK INTO THE AREA. LOOKS LIKE HIGH TERRAIN CONVECTION WILL HAVE A BETTER CHANCE OF MOVING THROUGH THE PANHANDLE AND INTO NRN PARTS OF THE FCST AREA. THE MIDDLE PART OF THE WEEK WILL THEN BE ONE WITH POSSIBILITY OF WEAKLY-FORCED DIURNAL DRYLINE STORMS WITH LOW LEVEL MOISTURE INCREASING WITH TIME...CONFLUENT FLOW ALOFT TRANSITIONING TO WEAK UPPER RIDGING. 20-30 PCT STORM CHANCES TUESDAY THROUGH FRIDAY LOOK FINE WITH THIS SYNOPTIC SETUP. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 40 70 40 65 / 0 0 10 0 TULIA 48 73 44 67 / 0 0 10 0 PLAINVIEW 49 73 45 68 / 0 0 0 0 LEVELLAND 45 75 46 70 / 0 0 0 0 LUBBOCK 50 76 47 71 / 0 0 0 0 DENVER CITY 44 74 47 71 / 0 0 0 0 BROWNFIELD 45 76 48 72 / 0 0 0 0 CHILDRESS 56 79 51 73 / 20 10 10 0 SPUR 54 79 50 73 / 20 0 0 0 ASPERMONT 57 81 52 77 / 20 10 10 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
154 AM EDT SAT APR 18 2015 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT AND SATURDAY BRINGING DRY AND WARM WEATHER FOR THE START OF THE WEEKEND. A COMPLEX STORM SYSTEM PASSING TO THE WEST WILL RESULT IN MORE WIDESPREAD RAIN 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 1012 PM EDT FRIDAY... ISOLD SHOWERS HAVE DISSIPATED AND SEE NO REASON FOR ANY NEW ONES TO FIRE UP OVERNIGHT...OTHER THAN ONE OR TWO ACROSS NORTHERN NC GIVEN MUCAPE VALUES STILL AROUND 300-500 J/KG. ALSO KEEPING AN EYE ON THE NORTHERN EDGE OF AREA OF SHOWERS INTO SW NC...WHICH IS AHEAD OF A SHORT WAVE NEAR CHATTANOOGA...AS SOMETHING COULD SNEAK INTO OUR NW NC MTNS AFTER MIDNIGHT...BUT MOST GUIDANCE AGREES THIS WILL STAY JUST TO OUR SOUTH. LEFT SLIGHT CHC POP ACROSS SOUTHERN EDGE OF FCST AREA THROUGH MUCH OF THE NIGHT...BUT REMOVED MENTION EVERYWHERE ELSE. TRENDS LOOK BETTER FOR MORE CLEARING FROM WEST LATE...AND THUS POSSIBILITY OF SOME PATCHY VALLEY FOG WITH WET GROUND SO ADDED THAT AS WELL...MAINLY TO MTN VALLEYS. OVERNIGHT TEMPS LOOK ON TRACK AT THIS POINT. PREV DISC AS OF 635 PM EDT FRIDAY... UPDATE TO REFLECT CURRENT MAINLY ISOLD COVERAGE OF SHOWERS FROM FOOTHILLS INTO SOUTHSIDE VA. INCLUDED A COUPLE HOURS OF CHC POPS ACROSS SOUTHSIDE THROUGH EARLY EVENING WITH CLUSTER OF SHOWERS THERE...AND SO FAR NOT SEEING ANY SIGNS OF EVEN INTERCLOUD LIGHTNING WITH CELLS NEAR MTV AND DAN...BUT KEEPING ISOLD THUNDER IN FCST GIVEN SBCAPES OF 500-800 J/KG....AND SOME ISOLD LTG IN CELLS JUST NORTHEAST OF BUCKINGHAM COUNTY. ALL THIS ACTIVITY SHOULD SLOWLY DIMINISH AS IT DRIFTS SOUTHEASTWARD INTO FAR NORTHERN NC BY 8 OR 9PM...AND RECENT HRRR RUNS SEEM TO BE DOING A BETTER JOB CAPTURING THE SPARSITY OF THE SHALLOW CONVECTION AND WEAKENING INTO THE EVENING HOURS WITH LOSS OF HEATING. SOME OF THE MORE WIDESPREAD LIGHT RAIN OVER FAR SW NC AND UPSTATE SC WILL SLIDE TO THE NORTHEAST IN ADVANCE OF WEAK SHORT WAVE HEADING EAST OUT OF TN...BUT PREVIOUS THINKING THAT IT WILL REMAIN SOUTH OF THE FCST AREA STILL LOOKS ON TRACK. WE DO KEEP A LINGERING SLIGHT CHC POP ACROSS NW NC MTNS UNTIL A LITTLE AFTER MIDNIGHT JUST IN CASE...BUT THEN DROP ALL POPS TOWARD MORNING. PREVIOUS DISCUSSION AS OF 235 PM EDT MONDAY... AT THE SFC...HIGH PRESSURE WILL SLOWLY NOSE SOUTH INTO THE EASTERN OHIO VALLEY BRINGING A LIGHT NORTH WIND. A SHALLOW LAYER OF MOISTURE NEAR THE SURFACE WILL REMAIN...WHICH WILL RESULT IN POCKETS OF FOG...ESPECIALLY WHERE CLOUDS ARE ABSENT TO THE NORTH. LEANED TOWARD THE WARMER GUIDANCE VALUES WITH CLOUDS. FOR SATURDAY...HEIGHTS BUILD IN ADVANCE OF A DEEP UPPER LEVEL TROF IN THE WEST AND TEMPS SHOULD AGAIN WARM WELL INTO THE 70S AND THE 80S IN THE EAST. A WEAK LOW LEVEL EAST FLOW COMBINED WITH A NOSE OF HIGHER THETA-E AIR IN NW NC INTO FAR SW VA MAY SPARK ISOLATED SHOWERS/STORMS. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... AS OF 330 PM EDT FRIDAY... FOCUS THROUGH THIS PERIOD REMAINS ON A STRONG NEGATIVELY TILTED UPPER TROUGH PROGGED TO LIFT RAPIDLY NORTHEAST ACROSS THE REGION SUNDAY INTO EARLY MONDAY. MEANWHILE...ANTECEDENT HIGH PRESSURE WILL MOVE OFF THE MID-ATLANTIC COAST INTO A NEAR CLASSIC WEDGE POSITION. STRONG PVA/ISENTROPIC LIFT INDUCED RAINFALL INTO THE WEDGE AIR MASS WILL ENHANCE/INTENSIFY THE WEDGE SUNDAY. RAINFALL/QPF WILL BE THE MAIN CONCERN AS THE WEDGE KEEPS A VERY STABLE/COOL AIR MASS IS PLACE. MOIST SOUTHEAST...UPSLOPE FLOW ALONG THE BLUE RIDGE WILL ENHANCE RAINFALL...ESPECIALLY ACROSS WATAUGA NORTHEAST TOWARD FLOYD. AS NOTED YESTERDAY...HOWEVER...THE SYSTEM WILL REMAIN HIGHLY PROGRESSIVE...LIMITING THE PERIOD OF HEAVIER RAINFALL TO 12 HOURS OR LESS. WPC HAS PARTS OF THE NC/VA SOUTHERN VA PIEDMONT OUTLOOKED FOR EXCESSIVE RAINFALL. THE MAIN CONCERN WITHIN THIS AREA WOULD BE WATAUGA THROUGH ASHE/WILKES...WITH LESS CONCERN TOWARD THE DANVILLE AREA WHERE ANTECEDENT CONDITIONS ARE RELATIVELY DRY. IN ADDITION...THE CONVECTIVE THREAT THROUGH THE HEAVIER RAIN PERIOD AS NOTED ABOVE IS MINIMAL TO NONE...WHICH SHOULD FURTHER REDUCE THE FLASH FLOOD THREAT. WILL RE-EVALUATE AGAIN TOMORROW...BUT AT THIS POINT NO NEED FOR A FLOOD/FLASH FLOOD WATCH. ONE MAY EVENTUALLY BE NEEDED FOR A SMALL AREA INCLUDING THE NW NC MOUNTAINS AND THE ADJACENT FOOTHILLS. WENT WELL BELOW GUIDANCE ON MAX TEMPS IN THE WEDGE SUNDAY...BUT AT OR ABOVE GUIDANCE ON MONDAY IN THE WARM SECTOR. MAX TEMPS MONDAY WILL BE A GOOD 20 DEGREES WARMER IN MOST AREAS THAN ON SUNDAY. MONDAY IS A DIFFERENT STORY. A SIGNIFICANT WARM SECTOR WILL SURGE NORTHWARD INTO THE REGION MONDAY AFTERNOON BEHIND THE DEPARTING UPPER TROUGH AND AN APPROACHING STRONG COLD FRONT ASSOCIATED WITH A DEEPENING BROAD UPPER TROUGH ACROSS THE GREAT LAKES. SEVERAL OF THE MODELS CONTINUE TO ADVERTISE GOOD POTENTIAL FOR STRONG THUNDERSTORMS MONDAY AFTERNOON...WITH SIGNIFICANT SVR PARAMETER NEAR 20000 ACROSS THE PIEDMONT...CAPES NEARING 2000 J/KG WITH AT LEAST 20-30KTS OF 0-2KM LOW-LEVEL SHEAR AND LIS NEAR -4C. SPC DAY 4 OUTLOOK SUGGESTS THAT DAMAGING WINDS WOULD BE THE MAIN CONCERN WITH ANY CONVECTION...MOST LIKELY LINEAR ORIENTED...THAT DEVELOPS ALONG/IN ADVANCE OF THE COLD FRONT MONDAY AFTERNOON/EVENING. THIS ACTIVITY QUICKLY MOVES EAST OF THE REGION MON AFTERNOON. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 345 PM EDT FRIDAY... A TRANSITION TO A PATTERN MORE REMINISCENT OF WINTER CONTINUES TO BE IN THE CARDS FOR THE EARLY AND MID PART OF NEXT WEEK AS A DEEP AND BROAD UPPER TROUGH BUILDS INTO THE CENTRAL/EASTERN U.S. BY TUESDAY...500MB HEIGHTS DROP INTO THE 560DM RANGE AND 850MB TEMPS PLUNGE TOWARD THE 0C MARK ACROSS THE NORTH BY MIDWEEK. ANTICYCLONIC FLOW...A SERIES OF EMBEDDED UPPER DISTURBANCES...AND COLD ADVECTION WILL KEEP VARIABLE CLOUDINESS AND POTENTIALLY UPSLOPE SHOWERS IN PLACE ACROSS THE MOUNTAINS. THE CLOUDS AND CYCLONIC FLOW WILL HOLD MAX TEMPS INTO THE 50S AND LOWER 60S ACROSS THE MOUNTAINS THROUGH MUCH OF THE LATER HALF OF NEXT WEEK...WHILE 60S TO 70S PREVAIL TO THE EAST WITH DOWNSLOPE NORTHWEST FLOW AND SIGNIFICANTLY GREATER AMOUNTS OF SUNSHINE. AT THIS POINT A DISTURBANCE ON WED APPEARS TO BE THE MOST SIGNIFICANT IN POTENTIALLY BRINGING SHOWERS EAST OF THE MOUNTAINS. HAVE NOT INTRODUCED ANY THUNDER AT THIS POINT GIVEN THE LOW-LEVEL COLD/STABLE AIR MASS. BY MID-WEEK...THE GFS/ECMWF BEGIN TO DIVERGE ON THE OVERALL PATTERN...WITH THE ECMWF KEEPING THE DEEP UPPER TROUGH IN PLACE ACROSS THE NORTHEAST AND A STRONGER NW FLOW INTO OUR REGION AS WELL...WHILE THE GFS DEPICTS THE UPPER TROUGH LIFTING FURTHER NORTH AND PLACING A ZONAL FLOW WITH A BAROCLINIC ZONE STUCK ACROSS OUR CWA. THIS RESULTS IN SIGNIFICANT DIFFERENCES BETWEEN MOISTURE/POPS ACROSS OUR CWA BETWEEN THE TWO MODELS...WITH THE GFS VERY WET AND THE ECMWF MUCH DRIER...KEEPING THE BAROCLINIC ZONE MUCH FURTHER SOUTH. HAVE JUST ADVERTISED CHC POPS FOR NOW UNTIL A BETTER HANDLE ON THIS PATTERN AND TIMING IS OBTAINED. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL THROUGH THE MID PART OF THE WEEK...GRADUALLY TRENDING CLOSER TO NORMAL BY THE END OF THE PERIOD. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 145 AM EDT SATURDAY... STARTING THE TAF PERIOD WITH WEAK HIGH PRESSURE AND LIGHT WINDS OVER THE MID ATLANTIC REGION. SOME FOG HAD DEVELOPED IN THE VALLEYS IN AREAS WHERE THE HIGH CLOUDS HAD CLEARED OUT. ISOLATED THUNDERSTORMS EAST OF LYNCHBURG WILL NOT IMPACT TAF SITES. LOCATIONS THAT HAVE SOME CLEARING EARLY THIS MORNING MAY HAVE FOG DEVELOPMENT...ESPECIALLY IN THE VALLEYS WEST OF THE BLUE RIDGE. HIGHEST CONFIDENCE OF FOG FORMING IS AT KBCB WERE THE DEW POINT DEPRESSION WAS ALREADY SMALL. FOG WILL BRING THE VISIBILITY DOWN TO IFR VALUES...POSSIBLY LIFR AT KLWB AFTER 10Z/6AM. ANY FOG AND LOW STRATUS DISSIPATES BY 13Z OR SO...FOR WIDESPREAD VFR CONDITIONS FOR THE DAY SATURDAY...WITH LIGHT EAST TO NORTHEAST WINDS AS SFC HIGH PRESSURE REMAINS TO THE NORTH AND WEAK SFC TROUGH WILL LINGER ACROSS NORTH CAROLINA. THIS MAY RESULT IN ENOUGH WEAK CONVERGENCE AND UPSLOPE TO KICK OFF A FEW ISOLD SHWRS OR TSTORMS BY AFTERNOON...ESPECIALLY NEAR BLUE RIDGE ALONG OR SOUTH OF VA/NC BORDER...BUT VERY UNLIKELY ANY ONE SHOWER OR STORM WILL IMPACT ANY AIRPORTS. EXTENDED AVIATION... A COMPLEX STORM SYSTEM WILL BEGIN TO AFFECT THE REGION SUNDAY WITH A WARM FRONT BRINGING WIDESPREAD MVFR/IFR CONDITIONS IN RAIN INTO SUNDAY NIGHT. THIS WILL BE FOLLOWED BY ANOTHER COLD FRONT MONDAY. THIS IS LIKELY TO KEEP PERIODS OF MVFR IN PLACE UNTIL THE FRONT POSSIBLY CLEARS THE REGION. 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. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PH NEAR TERM...JH/PH/SK SHORT TERM...RAB LONG TERM...RAB AVIATION...AMS/SK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
411 AM CDT SAT APR 18 2015 NEW INFORMATION ADDED TO UPDATE SECTION .UPDATE... ISSUED AT 407 AM CDT SAT APR 18 2015 AFTER FURTHER COORDINATION WITH ARX AND THE DNR...WILL ISSUE A RED FLAG WARNING FOR WOOD COUNTY. THE COMBO OF HUMIDITIES FALLING NEAR 20 PCT THIS AFTERNOON...MAX TEMPS IN THE 60S...WIND SPEEDS OF 10 TO 20 MPH...AND DRY FUELS WILL LEAD TO A CRITICAL FIRE WEATHER DAY THERE. THIS RED FLAG WARNING WILL TARGET THE PINE COUNTRY OF CENTRAL WISCONSIN. ADDITIONALLY...THE COLD FRONT HAS JUST PASSED OVER GREEN BAY. WINDS HAVE SHIFTED TO THE NORTH AND ARE GUSTING TO 22 KNOTS AT THE GRB AIRPORT. SOME GUSTS UP TO 25 KNOTS OVER THE BAY ARE ALSO OCCURRING. && .SHORT TERM...TODAY...TONIGHT...AND SUNDAY ISSUED AT 330 AM CDT SAT APR 18 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A FAIRLY POTENT COLD FRONT DROPPING SOUTH OVER FAR N-C WISCONSIN AND THE CENTRAL UPPER PENINSULA. NORTH WINDS BEHIND THE FRONT COMBINED WITH IMPRESSIVE PRESSURE RISES ARE CONTRIBUTING TO WIND GUSTS OVER 30 KTS OVER LAKE SUPERIOR. AS THE FRONT MOVES ACROSS NORTHERN WISCONSIN EARLY THIS MORNING...EXPECT NORTH WINDS TO STRENGTHEN AND BECOME GUSTY FOR PERIOD. ELSEWHERE...UPPER LEVEL LOW PRESSURE CONTINUES TO SPIN OVER THE CENTRAL ROCKIES AND PRODUCE SHOWERS AND THUNDERSTORMS ACROSS THE CENTRAL GREAT PLAINS. FORECAST CONCERNS INCLUDE FIRE WEATHER PARAMETERS TODAY...AND PRECIP CHANCES ON SUNDAY. TODAY...THE DRY COLD FRONT WILL DROP SOUTH ACROSS THE REST OF NORTHERN WISCONSIN EARLY THIS MORNING AND CENTRAL WISCONSIN BY MID-MORNING. BEHIND THE FRONT...THE MODELS ARE STILL DEPICTING VERY DRY AIR TO MOVE INTO NORTH-CENTRAL TO EAST-CENTRAL WISCONSIN TODAY. THOUGH NORTHEAST WINDS OFF LAKE MICHIGAN WILL HELP MODERATE THE DRY AIR OVER EASTERN WISCONSIN...MODEST WIND SPEEDS SHOULD BE ABLE TO TAP INTO THIS VERY DRY AIR JUST ABOVE THE INVERSION...AROUND 900MB. SO WAS AGGRESSIVE IN DROPPING HUMIDITIES TODAY...WHICH SHOULD FALL INTO THE TEENS OVER N-C WISCONSIN AND TO AROUND 25 PCT OVER CENTRAL WISCONSIN. EAST WINDS WILL ALSO BE APPROACHING CRITICALLY SUSTAINED SPEEDS OVER CENTRAL WISCONSIN THIS AFTERNOON. STILL WAITING FOR A FINAL DECISION FROM THE DNR CONCERNING A RED FLAG WARNING...WHICH SHOULD HAVE BY 5 AM. OTHERWISE...WILL SEE A SUNNY AND COOLER DAY. HIGHS IN THE LOW TO MID 60S AWAY FROM LAKE MICHIGAN. TONIGHT...CLOUDS WILL BE ON THE INCREASE AS THE CENTRAL ROCKIES UPPER LOW MOVES ACROSS THE CENTRAL PLAINS...WHILE A NORTHERN STREAM WAVE DIGS OVER THE NORTHERN PLAINS. AS CLOUDS THICKEN AND LOWER...WINDS BELOW 900MB WILL REMAIN OUT OF THE SOUTHEAST AND CONTINUE TO ADVECT VERY DRY AIR OVER THE REGION. THIS DRY AIR WILL HAVE TO BE OVERCOME...AND THIS MAY NOT OCCUR UNTIL LATE IN THE NIGHT OVER THE WEST. WILL MODIFY PRECIP CHANCES SLIGHTLY TO REFLECT THIS. LOWS RANGING FROM THE MID 30S NORTH TO THE MID 40S SOUTHWEST. SUNDAY...MID-LEVEL HEIGHT FALLS WILL CONTINUE TO ADVANCE INTO THE WESTERN GREAT LAKES. ONE AREA OF LOW PRESSURE WILL MOVE INTO WESTERN WISCONSIN DURING THE AFTERNOON...WHILE A SOUTHERN STREAM LOW SWINGS NE TOWARDS THE SOUTHERN TIP OF LAKE MICHIGAN. FORCING WILL IMPROVE THROUGH THE DAY AHEAD OF THESE FEATURES...THOUGH THE LEAD BAND OF LIGHT RAIN MAY DECAY DURING THE MORNING AS A RESULT OF THE DRY LOW LEVEL FLOW. THEN A SECOND ROUND OF PRECIP MAY TRY TO MOVE INTO THE AREA WITH THE APPROACHING LOW PRESSURE SYSTEMS. TEMPS ARE DIFFICULT BECAUSE OF THE PRECIP POTENTIAL...AMPLE CLOUD COVER...AND EAST WINDS. HAVE DROPPED TEMPS SOME SINCE TEMPS DO NOT TYPICALLY RISE WELL WHEN THERE IS CLOUD COVER AND EAST WINDS. PRECIP WILL ALSO LIKELY HOLD TEMPS BACK OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. SO WENT WITH HIGHS RANGING FROM THE MID 50S NORTH TO LOW 60S SOUTH. .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY ISSUED AT 330 AM CDT SAT APR 18 2015 500MB TROUGH WILL EVOLVE INTO A CLOSED UPPER LOW OVER THE WESTERN GREAT LAKES REGION EARLY NEXT WEEK...THEN MEANDER ACROSS EASTERN CANADA AND THE GREAT LAKES REGION THROUGH THE END OF NEXT WEEK. THIS WILL LEAD TO COOL AND UNSETTLED CONDITIONS...ALONG WITH A CHANCE OF SNOW LATE AT NIGHT AND EARLY MORNING HOURS. RAINFALL TOTALS STILL PROBLEMATIC SUNDAY NIGHT AS TWO SEPARATE SYSTEMS WILL BRING RAIN TO THE AREA. NORTHERN STREAM SYSTEM WILL BRING RAIN TO THE WESTERN HALF OF THE STATE...MEANWHILE A FAIRLY POTENT LOW PRESSURE SYSTEM WILL MOVE NORTHEAST INTO THE GREAT LAKES REGION SUNDAY NIGHT. STILL A LOT OF QUESTIONS ON TRACK OF SYSTEM DUE TO CLOSING UPPER LOW NORTHWEST OF THE STATE. MODEL QPF WOULD SUGGEST THAT MUCH NEEDED RAIN WOULD FALL ACROSS THE REGION. MAIN QUESTION IS WHERE AXIS OF HEAVIER RAIN WOULD FALL. MODEL RUN TO RUN CONTINUITY HAS NOT BEEN CONSISTENT...THUS LOW CONFIDENCE IN THE RAINFALL AMOUNT FORECAST. MONDAY IS NOT MUCH CLEARER AS SOME OF THE MODELS BRING DRY SLOT ACROSS THE AREA WITH A SIGNIFICANT DOWNWARD TREND IN RAINFALL AMOUNTS. THE ECMWF/CANADIAN DO NOT SHARE THIS TREND WITH THE WRF/GFS...THUS WILL KEEP SCATTERED DEPICTION/WORDING IN THE FORECAST. AS UPPER LOW CLOSES MONDAY NIGHT THROUGH WEDNESDAY...COOL CYCLONIC FLOW AND WEAK DISTURBANCES MOVING THROUGH THE MEAN FLOW WILL BRING CHANCES OF RAIN AND SNOW SHOWERS DEPENDING ON LOCATION AND TIMING OF THE DAY. AT SOME POINT...THERE COULD BE A MINOR ACCUMULATION OF SNOW ACROSS THE NORTH. SOME MODERATION IN TEMPERATURES IS EXPECTED BY THE END OF THE WEEK AS THE UPPER LOW GRADUALLY SHIFTS EAST OF THE AREA. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1100 PM CDT FRI APR 17 2015 VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. A DRY COLD FRONT WILL ARRIVE LATER TONIGHT. WINDS WILL SHIFT TO THE NORTHEAST BEHIND THE FRONT...AND BECOME GUSTY FOR A FEW HOURS TODAY...ESPECIALLY IN EASTERN WISCONSIN. WINDS WILL DIE DOWN AGAIN SATURDAY EVENING WITH THICKENING MID CLOUDS. && .GRB WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM CDT THIS EVENING FOR WIZ035. && $$ UPDATE.........MPC SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......KURIMSKI
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SUNDAY ISSUED AT 330 AM CDT SAT APR 18 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A FAIRLY POTENT COLD FRONT DROPPING SOUTH OVER FAR N-C WISCONSIN AND THE CENTRAL UPPER PENINSULA. NORTH WINDS BEHIND THE FRONT COMBINED WITH IMPRESSIVE PRESSURE RISES ARE CONTRIBUTING TO WIND GUSTS OVER 30 KTS OVER LAKE SUPERIOR. AS THE FRONT MOVES ACROSS NORTHERN WISCONSIN EARLY THIS MORNING...EXPECT NORTH WINDS TO STRENGTHEN AND BECOME GUSTY FOR PERIOD. ELSEWHERE...UPPER LEVEL LOW PRESSURE CONTINUES TO SPIN OVER THE CENTRAL ROCKIES AND PRODUCE SHOWERS AND THUNDERSTORMS ACROSS THE CENTRAL GREAT PLAINS. FORECAST CONCERNS INCLUDE FIRE WEATHER PARAMETERS TODAY...AND PRECIP CHANCES ON SUNDAY. TODAY...THE DRY COLD FRONT WILL DROP SOUTH ACROSS THE REST OF NORTHERN WISCONSIN EARLY THIS MORNING AND CENTRAL WISCONSIN BY MID-MORNING. BEHIND THE FRONT...THE MODELS ARE STILL DEPICTING VERY DRY AIR TO MOVE INTO NORTH-CENTRAL TO EAST-CENTRAL WISCONSIN TODAY. THOUGH NORTHEAST WINDS OFF LAKE MICHIGAN WILL HELP MODERATE THE DRY AIR OVER EASTERN WISCONSIN...MODEST WIND SPEEDS SHOULD BE ABLE TO TAP INTO THIS VERY DRY AIR JUST ABOVE THE INVERSION...AROUND 900MB. SO WAS AGGRESSIVE IN DROPPING HUMIDITIES TODAY...WHICH SHOULD FALL INTO THE TEENS OVER N-C WISCONSIN AND TO AROUND 25 PCT OVER CENTRAL WISCONSIN. EAST WINDS WILL ALSO BE APPROACHING CRITICALLY SUSTAINED SPEEDS OVER CENTRAL WISCONSIN THIS AFTERNOON. STILL WAITING FOR A FINAL DECISION FROM THE DNR CONCERNING A RED FLAG WARNING...WHICH SHOULD HAVE BY 5 AM. OTHERWISE...WILL SEE A SUNNY AND COOLER DAY. HIGHS IN THE LOW TO MID 60S AWAY FROM LAKE MICHIGAN. TONIGHT...CLOUDS WILL BE ON THE INCREASE AS THE CENTRAL ROCKIES UPPER LOW MOVES ACROSS THE CENTRAL PLAINS...WHILE A NORTHERN STREAM WAVE DIGS OVER THE NORTHERN PLAINS. AS CLOUDS THICKEN AND LOWER...WINDS BELOW 900MB WILL REMAIN OUT OF THE SOUTHEAST AND CONTINUE TO ADVECT VERY DRY AIR OVER THE REGION. THIS DRY AIR WILL HAVE TO BE OVERCOME...AND THIS MAY NOT OCCUR UNTIL LATE IN THE NIGHT OVER THE WEST. WILL MODIFY PRECIP CHANCES SLIGHTLY TO REFLECT THIS. LOWS RANGING FROM THE MID 30S NORTH TO THE MID 40S SOUTHWEST. SUNDAY...MID-LEVEL HEIGHT FALLS WILL CONTINUE TO ADVANCE INTO THE WESTERN GREAT LAKES. ONE AREA OF LOW PRESSURE WILL MOVE INTO WESTERN WISCONSIN DURING THE AFTERNOON...WHILE A SOUTHERN STREAM LOW SWINGS NE TOWARDS THE SOUTHERN TIP OF LAKE MICHIGAN. FORCING WILL IMPROVE THROUGH THE DAY AHEAD OF THESE FEATURES...THOUGH THE LEAD BAND OF LIGHT RAIN MAY DECAY DURING THE MORNING AS A RESULT OF THE DRY LOW LEVEL FLOW. THEN A SECOND ROUND OF PRECIP MAY TRY TO MOVE INTO THE AREA WITH THE APPROACHING LOW PRESSURE SYSTEMS. TEMPS ARE DIFFICULT BECAUSE OF THE PRECIP POTENTIAL...AMPLE CLOUD COVER...AND EAST WINDS. HAVE DROPPED TEMPS SOME SINCE TEMPS DO NOT TYPICALLY RISE WELL WHEN THERE IS CLOUD COVER AND EAST WINDS. PRECIP WILL ALSO LIKELY HOLD TEMPS BACK OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. SO WENT WITH HIGHS RANGING FROM THE MID 50S NORTH TO LOW 60S SOUTH. .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY ISSUED AT 330 AM CDT SAT APR 18 2015 500MB TROUGH WILL EVOLVE INTO A CLOSED UPPER LOW OVER THE WESTERN GREAT LAKES REGION EARLY NEXT WEEK...THEN MEANDER ACROSS EASTERN CANADA AND THE GREAT LAKES REGION THROUGH THE END OF NEXT WEEK. THIS WILL LEAD TO COOL AND UNSETTLED CONDITIONS...ALONG WITH A CHANCE OF SNOW LATE AT NIGHT AND EARLY MORNING HOURS. RAINFALL TOTALS STILL PROBLEMATIC SUNDAY NIGHT AS TWO SEPARATE SYSTEMS WILL BRING RAIN TO THE AREA. NORTHERN STREAM SYSTEM WILL BRING RAIN TO THE WESTERN HALF OF THE STATE...MEANWHILE A FAIRLY POTENT LOW PRESSURE SYSTEM WILL MOVE NORTHEAST INTO THE GREAT LAKES REGION SUNDAY NIGHT. STILL A LOT OF QUESTIONS ON TRACK OF SYSTEM DUE TO CLOSING UPPER LOW NORTHWEST OF THE STATE. MODEL QPF WOULD SUGGEST THAT MUCH NEEDED RAIN WOULD FALL ACROSS THE REGION. MAIN QUESTION IS WHERE AXIS OF HEAVIER RAIN WOULD FALL. MODEL RUN TO RUN CONTINUITY HAS NOT BEEN CONSISTENT...THUS LOW CONFIDENCE IN THE RAINFALL AMOUNT FORECAST. MONDAY IS NOT MUCH CLEARER AS SOME OF THE MODELS BRING DRY SLOT ACROSS THE AREA WITH A SIGNIFICANT DOWNWARD TREND IN RAINFALL AMOUNTS. THE ECMWF/CANADIAN DO NOT SHARE THIS TREND WITH THE WRF/GFS...THUS WILL KEEP SCATTERED DEPICTION/WORDING IN THE FORECAST. AS UPPER LOW CLOSES MONDAY NIGHT THROUGH WEDNESDAY...COOL CYCLONIC FLOW AND WEAK DISTURBANCES MOVING THROUGH THE MEAN FLOW WILL BRING CHANCES OF RAIN AND SNOW SHOWERS DEPENDING ON LOCATION AND TIMING OF THE DAY. AT SOME POINT...THERE COULD BE A MINOR ACCUMULATION OF SNOW ACROSS THE NORTH. SOME MODERATION IN TEMPERATURES IS EXPECTED BY THE END OF THE WEEK AS THE UPPER LOW GRADUALLY SHIFTS EAST OF THE AREA. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1100 PM CDT FRI APR 17 2015 VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. A DRY COLD FRONT WILL ARRIVE LATER TONIGHT. WINDS WILL SHIFT TO THE NORTHEAST BEHIND THE FRONT...AND BECOME GUSTY FOR A FEW HOURS TODAY...ESPECIALLY IN EASTERN WISCONSIN. WINDS WILL DIE DOWN AGAIN SATURDAY EVENING WITH THICKENING MID CLOUDS. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......KURIMSKI
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
512 AM MDT SAT APR 18 2015 .SHORT TERM...(TODAY THROUGH TONIGHT ) ISSUED AT 512 AM MDT SAT APR 18 2015 UPPER LOW NEAR WALSENBURG AT THIS TIME TRACKING SLOWLY EAST. DRY SLOT HAS CURLED AROUND ACROSS MOST OF EASTERN COLORADO WITH MOISTURE WRAPPING BACK FROM WYOMING INTO THE COLORADO MOUNTAINS. AT THIS TIME THE BACK PART OF THIS SYSTEM DOES NOT HAVE STRONG LIFT WITH IT...BUT THIS IS EXPECTED TO INCREASE DURING THE DAY AS EVERYTHING CONTINUES TO SPIN AROUND THE LOW CENTER MOVING SLOWLY EAST. A COMPLEX PATTERN...BUT THE GOOD NEWS IS THE MODELS HAVE PRETTY GOOD AGREEMENT ON THE BIG PICTURE. DETAILS OF JUST WHERE THE BANDING STRUCTURE AND CONVECTION ARE VARY CONSIDERABLY. LIKING THE HRRR PRESENTATION OF THE DEVELOPING BACK EDGE SNOW BAND ACROSS THE MOUNTAINS...ROUGHLY FROM LARAMIE TOWARD RIFLE THIS MORNING. HARD TO SAY IF THE NORTH CENTRAL MOUNTAINS WILL BE IN THE BEST OF THIS...OR IF IT WILL STAY FURTHER WEST WITH THE DRIER AIR CURLING BACK OVER THE FRONT RANGE. I DID INCREASE THE POPS FOR THE MOUNTAINS...HELD OFF ON INCREASING AMOUNTS TOO MUCH AS THE SNOW MAY TEND TOWARD LIGHT SHOWERS IN THE VALLEYS WITH A STEADY BACKGROUND OF LIGHT OROGRAPHIC SNOW. IF THAT BAND WOBBLES FURTHER EAST AN ADVISORY MAY BE NEEDED. MEANWHILE ON THE PLAINS THERE IS DRIER AIR ALOFT...BUT THE LOW LEVELS REMAIN MOIST AND THE COLD POOL ALOFT WILL BE OVER THIS AREA...AND THERE WILL BE SOME LIFT FROM THE TIP OF THE WARM ADVECTION NEAR THE LOW CENTER. CONVECTION SHOULD INCREASE THROUGH THE DAY. NOT AS MUCH OF A THUNDERSTORM RISK TODAY...CAPES LIKELY AROUND 300 J/KG AROUND DENVER AND 600 NEAR THE EASTERN BORDER. I WOULD SAY NEGLIGIBLE SEVERE THREAT EXCEPT FOR THE COLD TEMPERATURES...COULD BE SOME HAIL OUT EAST BUT IT SHOULD BE HARD TO GET LARGE HAIL. FOR TONIGHT THE BACK EDGE BAND WILL TRANSLATE ACROSS OUR AREA AS THE LOW MOVES EAST. THIS SHOULD BRING A BETTER CHANCE OF SHOWERS. NORTH WINDS ALSO INCREASING...WHICH COULD WARM/DRY AREAS NORTH OF DENVER BUT ENHANCE THE THREAT OF SNOW SOUTH OF DENVER. THE NORTH WIND SHOULD ALSO BRING A FEW DEGREES OF COOLING...LOWERING SNOW LEVELS BACK DOWN TO 5-6 THOUSAND FEET. HOWEVER AIR TEMPERATURES WILL STILL BE ABOVE FREEZING IN MOST AREAS...SO STILL EXPECTING LITTLE IMPACT FOR THE METRO AREA. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 512 AM MDT SAT APR 18 2015 THERE IS WEAK TO MODERATE NORTHWESTERLY JET LEVEL FLOW OVER THE CWA SUNDAY THROUGH MONDAY NIGHT. THERE IS WEAK DOWNWARD SYNOPTIC SCALE ENERGY FOR THE CWA SUNDAY...THEN BENIGN ENERGY SUNDAY NIGHT THROUGH MONDAY NIGHT. THERE IS NORTHERLY FLOW IN THE LOWER LEVELS ON SUNDAY...WITH WEAKER NORTHEASTERLIES SUNDAY NIGHT. BOUNDARY LAYER WINDS ARE NORTHWESTERLY ON MONDAY...THEN A HINT AT NORMAL DRAINAGE PATTERNS MONDAY NIGHT. FOR MOISTURE...THERE IS PLENTY FOR THE CWA SUNDAY AND SUNDAY NIGHT...THE NAM BEING THE DRIEST. THERE IS QUITE A BIT OF MOISTURE STILL AROUND BOTH MONDAY AND MONDAY NIGHT...THE GFS BEING THE WETTEST. THERE IS A BIT OF CAPE OVER THE FAR SOUTHWEST FORECAST AREA LATE DAY SUNDAY DAY. THERE IS A BIT MORE CAPE OVER ALL THE HIGH COUNTRY LATE DAY MONDAY...BUT STILL PRETTY MEAGER AMOUNTS. THE QPF FIELDS HAVE SOME MEASURABLE PRECIPITATION MOSTLY OVER THE WESTERN TWO-THIRDS OF THE CWA SUNDAY AFTERNOON INTO MONDAY EVENING. FOR POPS...20-50%S ARE GOOD SUNDAY INTO MONDAY...THE LOWER NUMBERS FOR THE PLAINS. FOR TEMPERATURES...SUNDAY`S HIGHS ARE A BIT COLDER THAN TODAY`S BEHIND THE COLD FRONT LATE TONIGHT...EARLY SUNDAY MORNING. MONDAY`S HIGHS ONLY WARM UP 1-2 C FROM SUNDAY`S. FOR THE LATER DAYS...TUESDAY THROUGH FRIDAY...THERE IS AN UPPER RIDGE TUESDAY THROUGH THURSDAY NOW ON THE MODELS. THE NEXT UPPER TROUGH LOOKS WEAKER THAN IT DID ON YESTERDAY`S 00Z RUNS AND IT COMES THROUGH THURSDAY NIGHT AND FRIDAY. && .AVIATION...(FOR THE TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 512 AM MDT SAT APR 18 2015 CONDITIONS WILL BE VARIABLE TODAY AS THERE WILL BE SCATTERED SHOWERS. FOR THE MORNING THERE WILL BE AREAS OF MVFR CEILINGS WITH A FEW PATCHES OF IFR. CEILINGS SHOULD BE HIGHER BY LATE MORNING...BUT STILL EXPECT LOCALIZED MVFR NEAR SHOWERS. THERE MAY BE LOWER CONDITIONS AGAIN THIS EVENING WHEN THERE IS A BETTER CHANCE OF SHOWERS...MAINLY MVFR BUT A SLIGHT CHANCE OF IFR CONDITIONS. WINDS WILL BE LIGHT AND MAINLY FROM THE NORTH OR NORTHWEST...BUT WITH SOME VARIABILITY. SNOW MAY MIX WITH THE RAIN TONIGHT...BUT NO RUNWAY ACCUMULATION IS EXPECTED AT THE DENVER AREA AIRPORTS. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GIMMESTAD LONG TERM...RJK AVIATION...GIMMESTAD
AREA FORECAST DISCUSSION
NWS ALBANY NY
1110 AM EDT SAT APR 18 2015 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE REGION TODAY...HOWEVER ITS ASSOCIATED MOISTURE IS RATHER LIMITED SO MAINLY ONLY AN INCREASE IN CLOUDS IS EXPECTED. IN ITS WAKE...WINDS WILL BECOME BREEZY FOR SEVERAL HOURS. HIGH PRESSURE WILL BUILD IN TONIGHT AND SUNDAY RESULTING IN FAIR AND DRY WEATHER. A SERIES OF WEATHER SYSTEMS WILL IMPACT THE REGION NEXT WEEK RESULTING IN COOL...DAMP...AND UNSETTLED CONDITIONS. A WIDESPREAD RAINFALL IS EXPECTED MONDAY AND MONDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... MORNING FOG BURNED OFF QUICKLY. A SHORT WAVE TROUGH AND ITS ASSOCIATED LOW PRESSURE SYSTEM WILL PASS JUST TO OUR NORTHEAST AND MOVE ACROSS NEW ENGLAND TODAY. MOISTURE REMAINS RATHER LIMITED WITH THIS SYSTEM. LATEST HRRR ONLY INDICATES SCATTERED CONVECTION SHOULD REMAINING MAINLY TO OUR NORTH AND EAST. THE BEST POTENTIAL FOR SOME BRIEF SHOWER WILL BE NORTH OF ALBANY AND INTO THE SOUTHERN GREENS OF VERMONT. THE MAIN ISSUE FOR THE DAY IS BREEZY WESTERLY WINDS DEVELOPING FOR THE AFTERNOON. MOMENTUM TRANSFER OF THE HIGHER MAGNITUDE WINDS SUGGEST WE TAP INTO H700 LAYER WHERE 30+KTS RESIDES...SO EXPECTING GUSTS OF 25 TO 35 MPH. AS FOR TEMPERATURES...GIVEN THE DEEP MIXING EXPECTED AND CURRENT TEMPERATURES RUNNING A COUPLE DEGREES WARMER...GUIDANCE AND DRY ADIABATIC DECENT OF THOSE PARCELS ALONG WITH FAVORED LOCATIONS FOR DOWNSLOPING WOULD YIELD TEMPERATURES AT 70F OR LOWER 70S FOR VALLEY LOCATIONS AND 50S FOR THE HIGHER TERRAIN. TONIGHT...SUBSIDENCE ALONG WITH DRIER AIR ALOFT AND SURFACE HIGH BUILDING INTO THE REGION WILL RESULT IN DIMINISHING WINDS AND ANY RESIDUAL CLOUD COVER. SO A CLEAR NIGHT EXPECTED WITH LOWS RANGING FROM THE UPPER 20S ACROSS THE DACKS TO AROUND 40F ALONG THE HUDSON RIVER FROM ALBANY AND POINT SOUTHWARD. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... GEN MODEL SUITE AGREEMENT HERE WITH SOME SPREAD TWRD THE END OF THE PERIOD...MAINLY ON QPF AMNTS. SUNDAY BEGINS WITH 500HPA RIDGE AXIS FM DELMARVA TO LK HURON...AND SFC HIGH RIDGING S FM QB. RESULT WILL BE WIDESPREAD SUBSIDENCE...LOW RH...LIGHT WINDS AND BRILLIANT SUNSHINE. SUN EVNG THE 500HPA RIDGE WILL SLIDE OFFSHORE ALONG WITH THE SFC HIGH. OVERNIGHT EVOLVING UPR GRT PLAINS 500HPA CUT OFF SHIFTS E...SHARPENING THE TROF/RIDGE AMPLITUDE AND SHORTING THE WAVELENGTH AND UVM. SFC CYCLOGEN ENSUES IN THE W OHIO VLY AND LIFTS NE INTO THE S GRTLKS MON. WMFNT TRAILS SE FM MI-VA CAPES...AND LIFTS TWRD RGN SUN NT AS SFC LOW ORGANIZES ON THE COAST. RESULT WILL BE RAPIDLY INCRG LLVL SFC WIND GRAD...INCRG LLVL JETS...AND MOISTURE INFLUX INTO RGN. SHRA WILL DEVELOP OVERNIGHT SUN AND EVOLVE INTO A WIDESPREAD RAIN INTO MON. THE 500HPA CUT OFF OVER THE GRT PLAINS MOVES LITTLE BY TUES ONLY REACHING LK SUPERIOR. WITH THE SFC LOW OVER ONTARIO...THE FRONTAL STRUCTURE HAS EVOLVED INTO AN OCCLUSION FM OTTAWA VLY TO CSTL LOW OVER S NEW ENG TUE MRNG. ONCE THE OCCLUSION CLEARS THE AREA...DRY SLOT WRAPS ACROSS REGION WITH GENERALLY IMPVG CONDS. ALTHOUGH THERE IS SOME SPREAD IN THE MODELS ON THE TIMING..ALL HAVE DONE SO BY 18UTC TUES. AS 500HPA SHORT WVS ARE IN ROTATION AROUND BASE OF CUTOFF TO OUR NW...SCT -SHRA MAY STILL OCCURRING IN STEEPENING LAPSE RATE OVER FCA. TEMPS WILL BE NR TO SLIGHTLY BLO NORMALS DURING THIS PERIOD WITH HIGHS IN THE UPPER 50S TO MID 60S SUNDAY...AND MAINLY IN THE 50S AFTERWARDS. LOWS WILL BE IN THE 30S WITH 40S TUESDAY MORNING. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... THIS PERIOD WILL BE DOMINATED BY A LARGE VERTICAL LOW PRESSURE SYSTEM CENTERED OVER ONTARIO...BUT IMPACTING MUCH OF EASTERN HALF OF CANADA AND NE USA. WHILE THE MODELS DIFFER IN TIMING AND PLACEMENT OF THE FEATURES...THE MAIN STORY WILL BE 500HPA SHORT WVS ROTATING AROUND THE LARGE CUTOFF...EACH DRAGGING A SFC FRONT/BOUNDARY THROUGH THE FCA. THESE FEATURES WILL PRODUCE VRBL CLOUDS...AND TRIGGER SCT TO AT TIMES BKN -SHRA... MAYBE SOME -SHSN AT HIR TRRN...HWVR THE ACTIVITY WILL BE DIURNALLY MODULATED AS STRONG APRIL SUN...AND STEEP LAPSE RATES WILL ENHANCE THE CONVECTIVE NATURE OF THE SYSTEM AN MAY EVEN RESULT IN SOME SMALL HAIL. AS ITS OFTEN WITH THESE EVENTS...WHEN FCA IS ON SE QUADRANT OF A MAJOR CUT OFF SYSTEM...THEY TEND TO OVER DO THE DISMAL CONDITIONS CLOUDS AND SHOWERS. FCST PERIOD WILL FEATURE BLO NORMAL TEMPS WITH HIGHS MAINLY 50S...LOWS IN THE 30S...VRBLE CLOUDS...SCT -SHRA/-SHSN. THESE WILL BE DRIVEN...DIURNALLY...WITH PASSING 500HPA SHORT WVS AND BY CDFNTS. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... APPEARS IFR CONDITIONS EVOLVED AT KGFL-KPSF OVERNIGHT WHERE DEWPOINT DEPRESSIONS QUICKLY COLLAPSED. THIS FOG SHOULD BE RATHER SHALLOW IN NATURE AND QUICKLY DISSIPATE WITH SUNRISE. DURING THE DAY...FRONTAL BOUNDARY WILL QUICKLY MOVE ACROSS THE REGION. WHILE MOISTURE REMAINS LIMITED WITH THIS SYSTEM...SOME SCT- BKN VFR CIGS ARE EXPECTED MAINLY AFFECTING KGFL-KPSF. OTHERWISE...WESTERLY WINDS WILL INCREASE WITH GUSTS OVER 20KTS...THEN WINDS SHIFTS TO THE NORTHWEST WITH EVEN SOME HIGHER GUSTS AROUND 25KTS. THE WINDS AND SKIES WILL ALL DISSIPATE THIS EVENING AS HIGH PRESSURE SETTLES ACROSS THE ENTIRE REGION WITH VFR CONDITIONS EXPECTED. OUTLOOK... SUNDAY NIGHT: HIGH OPERATIONAL IMPACT. BREEZY. LIKELY RA. MONDAY: HIGH OPERATIONAL IMPACT. BREEZY. DEFINITE RA. MONDAY NIGHT: HIGH OPERATIONAL IMPACT. DEFINITE RA. TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. WEDNESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. && .FIRE WEATHER... RED FLAG WARNING FOR ALL OF EASTERN NEW YORK...BERKSHIRES AND NORTHWEST CONNECTICUT LATER TODAY... GUSTY WINDS AND LOW RELATIVE HUMIDITIES FOR SOUTHERN VERMONT... EXTENSIVE COORDINATION OVERNIGHT ALONG WITH FORECAST METEOROLOGICAL CONDITIONS HAVE WARRANTED THE UPGRADE TO RED FLAG WARNINGS FOR EASTERN NEW YORK...BERKSHIRES AND NORTHWEST CONNECTICUT. WE WILL HIGHLIGHT THE LOW RELATIVE HUMIDITIES...SNOW COVERAGE INTO THE HIGHER TERRAIN...AND GUSTY WINDS WITH A SPECIAL WEATHER STATEMENT /SPS/ FOR SOUTHERN VERMONT. COMPACT WAVE TO THE NORTH OF THE GREAT LAKES WILL TRACK EAST- SOUTHEAST TODAY. MOISTURE ASSOCIATED WITH THIS SYSTEM REMAINS LIMITED...HOWEVER...ISOLATED SHOWERS ARE POSSIBLE MAINLY TO THE NORTH OF ALBANY AND INTO SOUTHERN VT AND PERHAPS TOUCHING NORTHERN BERKSHIRES. THEREAFTER...DEEP MIXING WITH INCREASING WINDS AND DROPPING RELATIVE HUMIDITY VALUES YIELDS A COMBINATION OF FIRE WEATHER HAZARDS TODAY. THE MAIN IMPACT POTENTIAL WILL BE DURING THE AFTERNOON HOURS. FOR SOUTHERN VERMONT...INCREASE IN CLOUD COVER ALONG WITH MARGINAL LEVELS FOR FIRE WEATHER...SNOW COVER ACROSS THE HIGHER TERRAIN AND COORDINATION WITH OFFICIALS HAVE RESULTED IN A SPECIAL WEATHER STATEMENT /SPS/. TONIGHT...WINDS WILL SUBSIDE ALONG WITH A SLOW RECOVERY OF THE RELATIVE HUMIDITY VALUES AS A SURFACE HIGH BUILDS INTO THE REGION. THIS HIGH REMAINS IN CONTROL THROUGH SUNDAY WITH LIGHT WINDS YET DRY CONDITIONS WITH MINIMUM RELATIVE HUMIDITY VALUES RANGING BETWEEN 20- 30 PERCENT. && .HYDROLOGY... NO HYDROLOGY ISSUES EXPECTED THROUGH THE MONDAY MORNING AS CONDITIONS WILL BE MAINLY DRY EXCEPT ISOLD -SHRA N TIER MIDDAY TODAY WITH A CFP. A WIDESPREAD SOAKING RAINFALL IS LIKELY LATE SUNDAY NIGHT INTO TUESDAY W/QPF ON THE ORDER OF HALF AN INCH TO AN INCH. THE NATIONAL OPERATIONAL HYDROLOGIC REMOTE SENSING CENTER (NOHRSC) INDICATES THAT THERE IS STILL A FEW INCHES OF WATER EQUIVALENT IN THE SNOW PACK ACROSS THE SRN ADIRONDACKS AND NORTHEASTERN BERKSHIRE COUNTY. PORTIONS OF THE SOUTHERN GREEN MOUNTAINS STILL HAVE 4 TO 9 INCHES OF SNOW WATER EQUIVALENT. THE GENERAL CONSENSUS IS FOR AROUND AN ONE INCH OF RAINFALL AT THIS TIME WITH THE HIGHER TOTALS SOUTH OF THE CAPITAL DISTRICT. THIS RAINFALL COMBINED WITH RISES FROM ONGOING SNOWMELT NORTH...MAY RESULT IN WITHIN BANK RISES MONDAY AND TUESDAY. 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...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR CTZ001-013. NY...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR NYZ032-033- 038>043-047>054-058>061-063>066-082>084. MA...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR MAZ001-025. VT...NONE. && $$ SYNOPSIS...IAA/SNYDER NEAR TERM...IAA/BGM/NAS/WASULA SHORT TERM...SNYDER LONG TERM...SNYDER AVIATION...BGM/NAS FIRE WEATHER...IRL/WASULA HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS WICHITA KS
1039 AM CDT SAT APR 18 2015 .SYNOPSIS... ISSUED AT 350 AM CDT SAT APR 18 2015 THE UPPER LOW HAS SHIFTED EASTWARD AND IS SPINNING OVER COLORADO. SMALL PIECES OF ENERGY WITH IT HAVE HELPED TO SPARK OFF SHOWERS AND THUNDERSTORMS OVER THE PLAINS STATES DURING THE OVERNIGHT HOURS. EXPECT CENTRAL AND EASTERN KANSAS TO SEE SHOWERS AND THUNDERSTORMS THROUGH MUCH OF THE MORNING. BILLINGS WRIGHT && .UPDATE... ISSUED AT 1037 AM CDT SAT APR 18 2015 MAIN UPPER LEVEL LOW OVER THE CO ROCKIES IS BEGINNING TO MAKE SLOW PROGRESS INTO THE PLAINS THIS MORNING. DIFFLUENT SW FLOW AHEAD OF THIS UPPER LOW HAS LED TO ANOTHER ROUND OF SHOWERS AND EMBEDDED STORMS OVER THE ERN HALF OF KS. EXPECT THE SHOWERS IN ERN KS TO GRADUALLY SHIFT TO THE E-NE OF THE AREA LATE THIS MORNING. BUT ATTENTION QUICKLY SHIFTS BACK TO THE WEST...AS THIS UPPER LOW BEGINS TO PUSH EAST INTO WRN KS. ALREADY SEEING SOME CLEARING ACROSS THE WESTERN HALF OF THE FORECAST AREA...WHICH WILL LEAD TO INCREASED SURFACE HEATING INTO THE AFTERNOON HOURS. SETUP IS A LITTLE DIFFERENT THAN YESTERDAY...AS DRYLINE IN SW KS IS ON THE MOVE TO THE EAST THIS MORNING...CURRENTLY JUST TO THE WEST OF THE KDDC. LATEST LOOK AT THE HI-RES SHORT TERM MODELS SUGGEST THAT THE INCREASED HEATING BETWEEN THE DRYLINE AND WRN SECTIONS OF THE FORECAST AREA WILL HELP DESTABILIZE THE ATMOSPHERE JUST TO THE WEST OF THE FORECAST AREA THIS AFTERNOON. THIS AREA IS ALSO WEAKLY CAPPED. SO BETTER HEATING THIS MORNING...AND NOT ALOT OF RECOVERY TIME NEEDED...MAY LEAD TO CONVECTION DEVELOPING EARLIER THAN YESTERDAY. ESPECIALLY JUST AHEAD OF THE DRYLINE AS IT PUSHES EAST OF KDDC...AND PUSHES TO JUST WEST OF KPPT. SO MAY SEE CONVECTION DEVELOP AND MOVE INTO WRN SECTIONS OF THE FORECAST AREA (WEST OF I- 135) BETWEEN 20-22Z. LATEST HRRR AND ARW SUGGEST THIS SCENARIO. AS FAR AS SEVERE WEATHER CHANCES...BULK SHEAR AROUND 40 KTS AND SBCAPE VALUES EXPECTED TO BE IN THE 2000-2500 J/KG SUGGEST A STRONG TO SEVERE CHANCE WITH A MIXED MODE WITH MULTICELL CLUSTERS AND A FEW LOW TOPPED SUPERCELLS WITH LARGE HAIL (QUARTER TO GOLFBALL) AND DAMAGING WINDS THE MAIN CONCERN. CANNOT RULE OUT A WEAK/BRIEF TORNADO OR TWO...GIVEN THE DIRECTIONAL SHEAR AND INCREASED VERTICAL STRETCHING DUE TO THE STEEP LAPSE RATES. KETCHAM && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 350 AM CDT SAT APR 18 2015 MORNING: EXPECT THE SHOWERS AND THUNDERSTORMS CURRENTLY ONGOING TO CONTINUE TO DEVELOP AND SHIFT EAST-NORTHEASTWARD DURING THE MORNING HOURS. DO NOT EXPECT THESE TO BE STRONG OR SEVERE...JUST A WELCOME DRINK OF RAIN. THIS AFTERNOON/EVENING: THINK THAT THERE MAY BE SOME CLEARING ACROSS WESTERN AREAS THIS MORNING/EARLY AFTERNOON BEFORE THUNDERSTORMS FIRE AGAIN THIS AFTERNOON ALONG AND AHEAD OF THE DRYLINE. STILL SLIGHTLY CONCERNED THAT STORMS COULD FIRE EARLIER IN THE AFTERNOON...CLOSER TO 18Z WITH THE SUPPORT FROM THE UPPER DYNAMICS OF THE UPPER LOW...HOWEVER...THE BEST SUPPORT FOR COVERAGE IS CLOSER TO 21Z TO 00Z. EXPECT THESE STORMS TO IMPACT CENTRAL AND SOUTH CENTRAL KANSAS WHERE INSTABILITY AND SHEAR PARAMETERS ARE PLENTIFUL TO SUPPORT SUPERCELLS CAPABLE OF LARGE HAIL AND DAMAGING WIND. THERE IS STILL A SMALL CHANCE FOR A TORNADO...BEST CHANCES RESIDE IN SOUTH CENTRAL KANSAS AND CLOSER TO THE OKLAHOMA BORDER WITH THE BETTER HELICITY/EHI FURTHER SOUTH IN OKLAHOMA. EXPECT STORMS TO MOVE EASTWARD DURING THE EVENING. THE SEVERE CHANCES DECREASE OVER SOUTHEAST KANSAS THOUGH AS THE PARAMETERS ARE LESS FAVORABLE THERE TO SUPPORT SEVERE STORMS. DURING THE OVERNIGHT HOURS SATURDAY INTO SUNDAY: THE UPPER LOW WILL CONTINUE TO PUSH EASTWARD AND LOBES OF VORTICITY ARE EXPECTED TO CIRCLE AROUND IT WHICH COULD SPARK MULTIPLE ROUNDS OF SHOWERS/THUNDERSTORMS OVER SOUTHERN KANSAS. THE UPPER LOW WILL TRAVERSE THE STATE SUNDAY...THUNDERSTORMS WILL BECOME SHOWERS AND THE FOCUS WILL SHIFT TO EAST AND SOUTHEAST KANSAS. A COLD FRONT ASSOCIATED WITH THE UPPER LOW WILL MOVE ACROSS THE STATE AND SHIFT WINDS TO THE NORTHWEST AND GUSTY. TEMPERATURES WILL BE COOLER ON MONDAY...IN THE 60S BUT THINGS SHOULD BE DRY AS THE UPPER LOW SLOWLY BEGINS TO SHIFT NORTHEASTWARD. BILLINGS WRIGHT .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 350 AM CDT SAT APR 18 2015 THE MAIN UPPER LOW IS SLOW TO EXIT AND A PIECE OF ENERGY ROTATING AROUND ITS BACK SIDE IT WILL IMPACT THE AREA WHILE THE CENTRAL PLAINS SITS UNDER NORTHWESTERLY UPPER LEVEL FLOW. PRECIPITATION CHANCES WILL BE POSSIBLE EARLY TUESDAY AND THROUGHOUT THE DAY...BUT THE GUIDANCE HAS DISCREPANCIES AMONGST THE LOCATION OF THE PRECIPITATION...THINK IT COULD BE SOUTH OF THE STATE LINE...HOWEVER THE GFS PUSHES IT RIGHT OVER CENTRAL KANSAS. CONFIDENCE ON THIS PERIOD AND PRECIPITATION CHANCES IS LOW. BY WEDNESDAY THROUGH FRIDAY THE UPPER LOW MOVES OFF TO THE NORTHEAST AND ANOTHER SYSTEM MOVES IN FROM THE SOUTHWEST. PRECIPITATION AND POSSIBLY THUNDERSTORM CHANCES INCREASE BY WEDNESDAY THROUGH FRIDAY ACROSS THE AREA. THIS PERIOD HAS QUITE A FEW DISCREPANCIES WITH THE VARIOUS SOLUTIONS...CONFIDENCE ON ANY SOLUTION IS LOW. TEMPERATURES WILL STAY IN THE UPPER 60S AND LOW 70S...NEAR SEASONAL NORMALS. BILLINGS WRIGHT && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 653 AM CDT SAT APR 18 2015 TOUGH AVIATION FORECAST. CONFIDENCE ONCE AGAIN NOT PARTICULARLY HIGH GIVEN CHALLENGES OF WEAKLY CAPPED/WEAK SURFACE CONVERGENCE PATTERN. STORMS WILL PERSIST FOR A FEW HOURS AT KCNU...WHILE REMAINDER OF THE AREA MORE THAN LIKELY DRY DURING THE MORNING. UPPER LOW HAS DRIFTED A BIT CLOSER...SO ONSET OF RENEWED CONVECTION MAY BE A BIT QUICKER THAN YESTERDAY...BUT STILL THINKING LATER IN THE AFTERNOON IN AT KRSL/KHUT...WITH KICT/KSLN VERY LATE AFTERNOON/EVENING AND KCNU LATER TONIGHT. -HOWERTON && .FIRE WEATHER... ISSUED AT 350 AM CDT SAT APR 18 2015 FIRE WEATHER CONCERNS REMAIN LOW WITH THE UPPER LEVEL SYSTEM IMPACTING THE AREA CAUSING MULTIPLE ROUNDS OF PRECIPITATION. THE GRASSLAND FIRE DANGER INDEX REMAINS BELOW ELEVATED CONCERN LEVELS. BILLINGS WRIGHT && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 75 54 66 39 / 50 60 70 10 HUTCHINSON 75 52 62 39 / 50 60 70 10 NEWTON 73 52 62 40 / 50 60 80 10 ELDORADO 74 54 69 41 / 40 60 80 10 WINFIELD-KWLD 74 54 70 40 / 40 60 70 10 RUSSELL 75 51 59 36 / 50 60 60 10 GREAT BEND 74 50 59 35 / 50 60 60 10 SALINA 76 52 61 38 / 50 60 70 10 MCPHERSON 74 52 60 38 / 50 60 70 10 COFFEYVILLE 73 56 70 43 / 80 60 80 20 CHANUTE 72 56 70 42 / 80 60 80 20 IOLA 71 56 69 42 / 80 60 80 20 PARSONS-KPPF 73 56 69 42 / 80 60 80 20 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
629 AM CDT Sat Apr 18 2015 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 342 AM CDT SAT APR 18 2015 Showers and thunderstorms developing this hour across northeast Oklahoma into south central and north central Kansas, with cell movement toward the north northwest and the cluster moving more northerly. This area is forecast to move across the forecast area through the morning hours today. Struggle with the forecast continues to be timing and coverage of precipitation chances. After initial energy lifts across Eastern Kansas through early afternoon, next uncertainty will be for chances later in the afternoon. HRRR develops a cluster of showers in south central KS, but would anticipate a break between the systems with subsidence behind the main wave inhibiting convective development. Have higher chances in the morning, with lower chances middle afternoon, followed by an increase from west to east through the evening into the overnight hours as the main wave finally starts to get an easterly push, from both a northern US shortwave and an upper jet traversing the southern states. With a lull in precipitation and possibly some better sunshine out west, this would boost instability and chances for severe thunderstorms as late day storms develop along the dryline to our west and along the northward advancing warm front. Primary threat would be hail, but closer proximity to these surface features in north central Kansas could bring an isolated tornado risk there. General precipitation chances continue in the overnight hours ahead of the upper low as it continues to slowly move east. Highs for Saturday in the middle 70s west to near 70 east, with lows in the 50s. .LONG TERM...(Sunday through Friday) Issued at 342 AM CDT SAT APR 18 2015 By Sunday morning the mid/upper low will be centered over SC KS and NC OK as it progresses eastward. During this time the low will become more of an open wave as another shortwave digs into the northern plains and upper Midwest. These waves will bring a cold front through the region during the day Sunday. In the morning the better chance for showers and some thunder should be in southern KS where the front and mid level low are more coupled in the vertical. By 18Z the models are hinting at an increase of instability on the order of about 1000 j/kg ahead of the front that should stretch across eastern KS. Lapse rates are not overly impressive, and deep layer shear could reach 30 kts. Although the better shear will be further southeast over southern MO where the flow aloft is slightly stronger. Therefore kept a mention of thunderstorms for east central KS during the afternoon. A majority of the precip should clear the area around 03Z in the evening. A sharp pressure gradient behind the front will support northwest surface winds around 15 to 25 mph with gusts as up to 35 mph especially in NC KS. Cold air advection on the backside of the wave drops temps into the lower 40s and upper 30s by Monday morning. Winds do not completely decouple Sunday night so there is little concern for frost. On Monday winds remain gusty with high temps generally around 60 and partly sunny skies. Monday night will not be the classic set up for frost with a expansive high building southward, but the winds do decrease and temps are forecast to reach the mid to upper 30s. Therefore could not rule out the possibility for frost perhaps in preferred sheltered locations. NW flow aloft develops over the region as the northern stream wave deepens over the Great Lakes. The models are beginning to advertise embedded shortwaves within the NW flow, which track over the plains around mid week. This will bring small chances for either showers or thunderstorms. Late in the week a southern wave crashes the southern CA coast and tracks northeastward towards the center of the country. There are some differences on how far north the instability reaches ahead of the system, and there are additional waves in the NW flow that could interfere with the southern stream system. Confidence in any solution is low at this point. && .AVIATION...(For the 12Z TAFs through 12Z Sunday Morning) Issued at 624 AM CDT SAT APR 18 2015 TAFs are generally VFR as first round of rain and isolated thunder move across the area in the morning. Another round is expected later this evening as storms develop west of the terminals and move east. Coverage in between expected to be sporadic and won`t mention more than VCTS at this time for the afternoon evening hours. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...67 LONG TERM...Sanders AVIATION...67
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1126 AM EDT SAT APR 18 2015 LATEST UPDATE... HYDRO .SYNOPSIS... ISSUED AT 328 AM EDT SAT APR 18 2015 ANOTHER SUNNY DAY IS EXPECTED TODAY WITH HIGHS AROUND 70. LOW PRESSURE WILL MOVE NORTH FROM THE GULF AREA SUNDAY BRINGING QUITE A BIT OF RAIN WITH IT. AFTER THE LOW MOVES EAST...COLDER AIR WILL MOVE OVER LOWER MICHIGAN AND REMAIN IN PLACE NEXT WEEK. HIGHS WILL ONLY REACH THE MID 40S TO MID 50S NEXT WEEK. && .UPDATE... ISSUED AT 1055 AM EDT SAT APR 18 2015 I INCREASED THE HIGH TEMPERATURE AROUND 5 DEGREES FOR THIS AFTERNOON BASED ON MORNING SOUNDING DATA. THE RAP MODEL SEEMS TO BE DOING A BETTER JOB OF SHOWING CURRENT TEMPERATURES...DEW POINTS AND WINDS SO I USED THAT TO INCREASE THE WIND SPEED...TEMPERATURES AND LOWER THE DEW POINTS. THAT ALL BEING SO... WE COULD SEE HIGHS IN THE MID TO UPPER 70S OVER THE WESTERN SECTIONS OF THE CWA THIS AFTERNOON. WE WILL BE GETTING CLOSE TO RED FLAG CONDITIONS IF THIS HAPPENS. FOR NOW I WILL LET OUR HWO AND POST OF FACEBOOK COVER THIS ISSUE. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 328 AM EDT SAT APR 18 2015 FORECAST CONCERNS DEAL WITH THE LOW APPROACHING SUNDAY. AFTER ANOTHER SUNNY AND MILD DAY TODAY CLOUDS WILL INCREASE TONIGHT AS A PHASED NORTHERN/SOUTHERN STREAM LOW APPROACHES FROM THE SOUTH. STRONG 60KT LLJ WILL DRAW UP ABUNDANT MOISTURE INTO THE SYSTEM. STRONG ISENTROPIC LIFT LATE SUNDAY MORNING WILL LEAD TO RAPID RAIN DEVELOPMENT FROM SOUTH TO NORTH. LOOK FOR THE WIND TO INCREASE AS WELL...AT LEAST UNTIL THE LOW MOVES OVERHEAD SUNDAY EVENING. SHORT RANGE MODELS HAVE BEEN CONSISTENT MOVING THE LOW DIRECTLY OVER THE CWA SO CONFIDENCE IS PRETTY HIGH WE/LL SEE RAIN. QPF AROUND 3/4 INCH LOOKS POSSIBLE AS MIXING RATIOS CLIMB TO 8G/KG BY LATE SUNDAY AFTERNOON. THERE STILL ISN/T A STRONG SIGNAL FOR THUNDER SO WE KEPT IT OUT OF THE GRIDS. HOWEVER GIVEN A SLIGHT DECREASE IN STABILITY NOTED WE CAN/T RULE IT OUT EITHER. MONDAY WILL BE MUCH COOLER AS THE LOW MOVES EAST AND WEST WINDS DEVELOP. HIGHS IN THE MID 50S ARE EXPECTED. THE UPPER LOW WILL MOVE OVER THE CWA MONDAY SO WE/LL CONTINUE TO SEE SCATTERED SHOWERS. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 328 AM EDT SAT APR 18 2015 MOST OF NEXT WEEK WILL BE COLDER THAN NORMAL WITH SCATTERED RAIN OR MIXED RAIN AND SNOW SHOWERS AS AN UPPER LOW BECOMES PARKED OVER THE NORTHERN GREAT LAKES REGION. DEEP CYCLONIC FLOW AND COLD ADVECTION WILL LEAD TO CONSIDERABLE CLOUDINESS WITH HIGHS ONLY IN THE 40S AND FREQUENTLY BREEZY CONDITIONS. THE MAIN RISK FOR SNOW SHOWERS WILL BE AT NIGHT AND DURING THE EARLY MORNING WHEN THE BOUNDARY LAYER IS COOLEST... ESPECIALLY FOR HIGHER ELEVATIONS NEAR AND NORTH OF ROUTE 10 WHERE SOME LIGHT ACCUMULATIONS EVEN APPEAR POSSIBLE. GFS/ECMWF DO NOT LOOK PARTICULARLY BULLISH WITH QPF AT ANY TIME NEXT WEEK ALTHOUGH SPOKES OF VORTICITY ROTATING AROUND THE UPPER LOW MAY LEAD TO OCCASIONAL BOUTS OF INCREASED COVERAGE OF HEAVIER SHOWERS. THINGS APPEAR TO DRY OUR THURSDAY NIGHT AND FRIDAY WHEN THE UPR LOW MOVES EAST AND SFC RIDGING ARRIVES FROM THE WEST. BY FRIDAY HIGHS COULD BE BACK UP INTO THE 50S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 745 AM EDT SAT APR 18 2015 SFC WINDS WILL INCREASE OUT OF THE NORTHEAST LATER THIS MORNING... WITH SPEEDS OF 10 TO 20 KTS BECOMING COMMON BY AFTERNOON. THE WINDS INCREASE FURTHER AFTER 20Z... WITH SOME GUSTS TO 30 KTS POSSIBLE LATE TODAY INTO TONIGHT. HIGH CONFIDENCE IN VFR CIGS/VSBYS CONTINUING TODAY AND TONIGHT. && .MARINE... ISSUED AT 328 AM EDT SAT APR 18 2015 A COLD FRONT WILL MOVE THROUGH EARLY TODAY AND TURN THE WINDS TO THE NORTHEAST. THE OFFSHORE FLOW WILL CONTINUE TONIGHT AND STRENGTHEN. A SCA MAY BE NEEDED TONIGHT. && .HYDROLOGY... ISSUED AT 1126 AM EDT SAT APR 18 2015 A GOOD SOAKING RAINFALL IS STILL ON TRACK TO AFFECT THE ENTIRE AREA BEGINNING SUNDAY. THE BULK OF THE MOISTURE WILL LIKELY FALL BETWEEN SUNDAY AFTERNOON INTO MONDAY MORNING WITH SOME GUIDANCE HINTING AT OVER AN INCH IN SPOTS. ADDITIONAL CHANCES FOR RAIN WILL SPAN THROUGH THE MIDDLE OF THE WEEK BUT ARE NOT EXPECTED TO BE QUITE AS ABUNDANT WITH MOISTURE. RIVERS WILL MAINLY RESPOND IN THE MANNER OF MINOR RISES. THIS SHOULD MOSTLY CONSIST OF WITHIN BANK RISES. I HAVE A LITTLE MORE CONFIDENCE IN THINKING MAPLE RAPIDS COULD FLIRT WITH ADVISORY CRITERIA ONCE AGAIN. THIS IS PENDING THE AMOUNT OF RAINFALL RECEIVED THROUGH EARLY MONDAY. OTHERWISE...WE ARE LOOKING PRETTY GOOD WITH THIS NOT BEING A CONVECTIVE MODE OF PRECIPITATION...NO REAL SURPRISES AT THIS POINT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...04 SHORT TERM...04 LONG TERM...MEADE AVIATION...MEADE HYDROLOGY...JAM MARINE...04
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1056 AM EDT SAT APR 18 2015 LATEST UPDATE... UPDATE .SYNOPSIS... ISSUED AT 328 AM EDT SAT APR 18 2015 ANOTHER SUNNY DAY IS EXPECTED TODAY WITH HIGHS AROUND 70. LOW PRESSURE WILL MOVE NORTH FROM THE GULF AREA SUNDAY BRINGING QUITE A BIT OF RAIN WITH IT. AFTER THE LOW MOVES EAST...COLDER AIR WILL MOVE OVER LOWER MICHIGAN AND REMAIN IN PLACE NEXT WEEK. HIGHS WILL ONLY REACH THE MID 40S TO MID 50S NEXT WEEK. && .UPDATE... ISSUED AT 1055 AM EDT SAT APR 18 2015 I INCREASED THE HIGH TEMPERATURE AROUND 5 DEGREES FOR THIS AFTERNOON BASED ON MORNING SOUNDING DATA. THE RAP MODEL SEEMS TO BE DOING A BETTER JOB OF SHOWING CURRENT TEMPERATURES...DEW POINTS AND WINDS SO I USED THAT TO INCREASE THE WIND SPEED...TEMPERATURES AND LOWER THE DEW POINTS. THAT ALL BEING SO... WE COULD SEE HIGHS IN THE MID TO UPPER 70S OVER THE WESTERN SECTIONS OF THE CWA THIS AFTERNOON. WE WILL BE GETTING CLOSE TO RED FLAG CONDITIONS IF THIS HAPPENS. FOR NOW I WILL LET OUR HWO AND POST OF FACEBOOK COVER THIS ISSUE. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 328 AM EDT SAT APR 18 2015 FORECAST CONCERNS DEAL WITH THE LOW APPROACHING SUNDAY. AFTER ANOTHER SUNNY AND MILD DAY TODAY CLOUDS WILL INCREASE TONIGHT AS A PHASED NORTHERN/SOUTHERN STREAM LOW APPROACHES FROM THE SOUTH. STRONG 60KT LLJ WILL DRAW UP ABUNDANT MOISTURE INTO THE SYSTEM. STRONG ISENTROPIC LIFT LATE SUNDAY MORNING WILL LEAD TO RAPID RAIN DEVELOPMENT FROM SOUTH TO NORTH. LOOK FOR THE WIND TO INCREASE AS WELL...AT LEAST UNTIL THE LOW MOVES OVERHEAD SUNDAY EVENING. SHORT RANGE MODELS HAVE BEEN CONSISTENT MOVING THE LOW DIRECTLY OVER THE CWA SO CONFIDENCE IS PRETTY HIGH WE/LL SEE RAIN. QPF AROUND 3/4 INCH LOOKS POSSIBLE AS MIXING RATIOS CLIMB TO 8G/KG BY LATE SUNDAY AFTERNOON. THERE STILL ISN/T A STRONG SIGNAL FOR THUNDER SO WE KEPT IT OUT OF THE GRIDS. HOWEVER GIVEN A SLIGHT DECREASE IN STABILITY NOTED WE CAN/T RULE IT OUT EITHER. MONDAY WILL BE MUCH COOLER AS THE LOW MOVES EAST AND WEST WINDS DEVELOP. HIGHS IN THE MID 50S ARE EXPECTED. THE UPPER LOW WILL MOVE OVER THE CWA MONDAY SO WE/LL CONTINUE TO SEE SCATTERED SHOWERS. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 328 AM EDT SAT APR 18 2015 MOST OF NEXT WEEK WILL BE COLDER THAN NORMAL WITH SCATTERED RAIN OR MIXED RAIN AND SNOW SHOWERS AS AN UPPER LOW BECOMES PARKED OVER THE NORTHERN GREAT LAKES REGION. DEEP CYCLONIC FLOW AND COLD ADVECTION WILL LEAD TO CONSIDERABLE CLOUDINESS WITH HIGHS ONLY IN THE 40S AND FREQUENTLY BREEZY CONDITIONS. THE MAIN RISK FOR SNOW SHOWERS WILL BE AT NIGHT AND DURING THE EARLY MORNING WHEN THE BOUNDARY LAYER IS COOLEST... ESPECIALLY FOR HIGHER ELEVATIONS NEAR AND NORTH OF ROUTE 10 WHERE SOME LIGHT ACCUMULATIONS EVEN APPEAR POSSIBLE. GFS/ECMWF DO NOT LOOK PARTICULARLY BULLISH WITH QPF AT ANY TIME NEXT WEEK ALTHOUGH SPOKES OF VORTICITY ROTATING AROUND THE UPPER LOW MAY LEAD TO OCCASIONAL BOUTS OF INCREASED COVERAGE OF HEAVIER SHOWERS. THINGS APPEAR TO DRY OUR THURSDAY NIGHT AND FRIDAY WHEN THE UPR LOW MOVES EAST AND SFC RIDGING ARRIVES FROM THE WEST. BY FRIDAY HIGHS COULD BE BACK UP INTO THE 50S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 745 AM EDT SAT APR 18 2015 SFC WINDS WILL INCREASE OUT OF THE NORTHEAST LATER THIS MORNING... WITH SPEEDS OF 10 TO 20 KTS BECOMING COMMON BY AFTERNOON. THE WINDS INCREASE FURTHER AFTER 20Z... WITH SOME GUSTS TO 30 KTS POSSIBLE LATE TODAY INTO TONIGHT. HIGH CONFIDENCE IN VFR CIGS/VSBYS CONTINUING TODAY AND TONIGHT. && .MARINE... ISSUED AT 328 AM EDT SAT APR 18 2015 A COLD FRONT WILL MOVE THROUGH EARLY TODAY AND TURN THE WINDS TO THE NORTHEAST. THE OFFSHORE FLOW WILL CONTINUE TONIGHT AND STRENGTHEN. A SCA MAY BE NEEDED TONIGHT. && .HYDROLOGY... ISSUED AT 1119 AM EDT FRI APR 17 2015 NO RIVER FLOOD ADVISORIES ARE IN EFFECT AT THIS TIME. IMPROVEMENT IS EXPECTED TO CONTINUE AS DRY CONDITIONS WILL HOLD STRONG TODAY THROUGH SATURDAY. THOUGHTS ON THE NEXT ROUND OF MOISTURE ARE CONSISTENT WITH THE PREVIOUS HYDRO UPDATE (4/16). A DECENT SOAKING RAIN IS EXPECTED TO MOVE IN SUNDAY WITH OFF/ON WET WEATHER POSSIBLE THROUGH THE MIDDLE OF NEXT WEEK. MUCH OF THE MOISTURE SHOULD FALL LATE IN THE WEEKEND AND EARLY INTO THE NEW WORK WEEK. THIS COULD RESULT IN MINOR UPTICKS FOR RIVERS. THE LACK OF CONVECTIVE ACTIVITY...OR HIGH END HEAVIER RAINFALL...KEEPS ME SOMEWHAT CONSERVATIVE ON ANY RISES THAT WOULD OTHERWISE BE MORE CONCERNING. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...04 SHORT TERM...04 LONG TERM...MEADE AVIATION...MEADE HYDROLOGY...JAM MARINE...04
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1025 AM CDT SAT APR 18 2015 .UPDATE... THINGS THIS MORNING ARE EVOLVING GENERALLY AS ANTICIPATED...ALTHOUGH QUESTION MARKS GOING INTO LATE TODAY STILL PERSIST IN SOME MEASURE OWING TO THUNDERSTORMS ANCHORED TO THE SE LA COAST. THESE STORMS WERE PREVIOUSLY SPREADING A LIGHT RAIN SHIELD INTO MY SOUTHERN ZONES...BUT THE NORTHWARD EXTENT OF THIS PRECIP HAS SHRUNK IN THE LAST FEW HOURS. ALSO...VIGOROUS STORMS JUST SOUTH OF THE COAST HAVE BEEN GRADUALLY LOSING COVERAGE SINCE DAYBREAK AND THEY SHOULD EBB QUICKLY INTO MIDDAY AS UPPER JET PULLING BACK TO THE WEST REMOVES MUCH OF THE UPPER LEVEL SUPPORT. HOWEVER...IF SAID EVOLUTION DOES NOT COME TO PASS WITH HASTE THEN MOISTURE TRANSPORT BLOCKING AND CLOUD COVER INTO SOME OF MY SOUTHERN ZONES WILL HINDER POTENTIAL FOR VIGOROUS INLAND THUNDERSTORM FORMATION AS WE GO INTO THIS AFTERNOON. BUT ASSUMING THE LATTER CAVEAT IS NOT AN ISSUE...LATEST HRRR AND DOWNSCALED NAM RUNS POINT TO WORRISOME STORMS MOVING INTO MY SOUTHERN ZONES (ESPECIALLY SOUTH CENTRAL AND SE MS) ZONES FROM MID AFTERNOON THROUGH MID EVENING. ATMOSPHERIC LAPSE RATES WILL MAINLY BE AT OR LESS THAN 6 C/KM IN THE H700-H500 LAYER BUT MLCAPE PEAKING OVER 1000 J/KG SHOULD BE SUFFICIENT GIVEN EXPECTED LOW LEVEL AND DEEP LAYER SHEAR TO PRODUCE ORGANIZED STORMS. ONCE AGAIN...A FEW TORNADOES CANNOT BE RULED OUT. THERE IS NOT ENOUGH EVIDENCE YET TO GO CHANGING THE PREVIOUS FORECAST AND SEVERE WEATHER EXPECTATIONS MUCH. HOWEVER...WE WILL BE WATCHING TRENDS CLOSELY OVER THE NEXT FEW HOURS AND WILL SEE IF VERY RECENT HRRR HINTS THAT SEVERE RISK WILL BE STRONGLY FOCUSING SOUTHEAST OF THE NATCHEZ TRACE APPEAR SOLID. IF THAT IS THE CASE WE WILL UPDATE ACCORDINGLY...BUT EVEN IF WE DO FOCUS THE SEVERE RISK EVEN MORE CONSIDERABLY IN SOUTHERN ZONES THE RISK OF LOCALIZED FLOODING PROBLEMS STILL LOOKS TO EXTEND ACROSS A MUCH LARGER PORTION OF THE FORECAST AREA. /BB/ && .AVIATION...IFR CATEGORY STRATUS PREVAILS ACROSS THE TAF SITES THIS MORNING WITH SHOWERS MOVING ACROSS HBG. EXPECT THESE CONDITIONS TO PERSIST UNTIL LATE MORNING/EARLY AFTERNOON BEFORE FINALLY MIXING OUT. SHRA WILL MOSTLY CONFINED TO LOCATIONS SOUTH OF THE HEZ-HBG CORRIDOR THIS MORNING AS A CONVECTIVE COMPLEX SLIDES EASTWARD ALONG THE COAST...BUT A NEW ROUND OF SHRA/TSRA IS EXPECTED BY MID/LATE AFTERNOON LASTING INTO THE EVENING WITH AN APPROACHING DISTURBANCE. THERE MAY BE A WINDOW OF OPPORTUNITY FOR BETTER FLYING CONDITIONS DURING THE EARLY AFTERNOON...FOLLOWED BY POOR FLYING CONDITIONS PERSISTING FROM MID/LATE AFTERNOON THROUGH THE EVENING. /EC/15/ && .PREV DISCUSSION... /ISSUED 454 AM CDT SAT APR 18 2015/ SHORT TERM...TODAY THROUGH TONIGHT...AN ACTIVE WEATHER WEEKEND IS IN STORE AS TWO ROUNDS OF SEVERE WEATHER ARE EXPECTED TO IMPACT THE ARKLAMISS. THE FIRST ROUND WILL BE INITIATED BY INCREASINGLY FAVORABLE CYCLONIC AND SHEARED FLOW DEVELOPING OVER THE LOWER MS VALLEY REGION LATER THIS AFTERNOON AND EVENING. THE CONVECTIVE SYSTEM CURRENTLY MOVING EAST ALONG THE THE LA COAST WILL DELAY TIMING OF THE MORE SIGNIFICANT THUNDERSTORM ACTIVITY UNTIL MID/LATE AFTERNOON...BUT VERY MOIST AND UNSTABLE AIR WITH PRECIPITABLE WATER VALUES > 1.75 INCHES AND ML CAPE NEAR 1000 J/KG SHOULD BE AVAILABLE FOR VIGOROUS CONVECTIVE DEVELOPMENT AT THAT TIME. WITH DEEP LAYER AND LOW LEVEL SHEAR ON THE INCREASE...STILL EXPECT ORGANIZED STORMS TO DEVELOP WITH THE MOST FAVORABLE SET-UP FOR SEVERE WEATHER AND HEAVY RAINFALL ALONG/SOUTH OF THE I-20 CORRIDOR...BUT WILL SAY THAT CONFIDENCE IS A LITTLE SHAKIER NOW ON THIS SCENARIO BASED ON RECENT HIGH RES GUIDANCE TRENDS. IF THE NEXT ROUND OF CONVECTIVE DOES NOT MATERIALIZE AS ANTICIPATED DUE TO THE MORNING CONVECTION...OR IF IT DEVELOPS FARTHER EAST...THEN IT IS POSSIBLE THAT MORE ROBUST CONVECTION WOULD IMPACT NORTHERN PORTIONS OF THE ARKLAMISS AND THIS COULD ALLOW THE SEVERE WEATHER/HEAVY RAINFALL THREAT TO SHIFT FARTHER NORTH AS WELL. STAY TUNED FOR UPDATES TO THIS FORECAST LATER THIS MORNING AS CONVECTIVE EVOLUTION HOPEFULLY BECOMES A LITTLE MORE CLEAR. /EC/ SUNDAY THROUGH SUNDAY NIGHT...MODELS FOR SUNDAY CONTINUE TO SUPPORT THE RISK FOR SEVERE STORMS ALONG WITH SOME POTENTIAL FOR A HIGHER END EVENT. WHAT IS STARTING TO BECOME MORE CLEAR IS MUCH OF THE DAY LOOKS TO BE IN A LULL FROM CONVECTION AFTER MORNING ACTIVITY DEPARTS TO THE EAST AND THE ROUND OF STORMS WILL BE MORE FOCUSED LATER BETWEEN A 5PM TO 3AM WINDOW. IN THE WAKE OF THE SAT SYSTEM...MUCH STEEPER LAPSE RATES WILL SPREAD OVER THE AREA (7.0 TO 7.5 C/KM)(29-31C VERTICAL TOTALS). ALOFT MUCH COLDER TEMPS WILL MOVE IN WITH H5 READINGS OF -15 TO - 16C. THIS WILL ALL SUPPORT SBCAPE OF 2000-3000 J/KG AS SFC HEATING REACHES AROUND 80 DEGREES. THIS WILL ALL SUPPORT VIGOROUS STORMS WITH ROBUST UPDRAFTS. CONCURRENT WITH THIS WILL BE AN OVERALL DRIER ATMOSPHERE COLUMN AS WELL WITH PWS AROUND 1.2 INCHES. THIS WILL LEND TO KEEPING STORMS MORE DISCRETE ALONG WITH AN EASTWARD DEEP LAYER (0-6KM) SHEAR VECTOR OF 40-50KTS. EXPECTATIONS ARE FOR NOT MANY (ISO/SCT) SUPERCELLS THAT WILL PACK QUITE THE PUNCH. LARGE HAIL > GOLF BALL SIZE APPEARS VERY POSSIBLE ALONG WITH DAMAGING WINDS WHICH ALSO COULD BE HIGHER END. DUE TO THIS POSSIBILITY OF SEEING SIGNIFICANT TYPE WEATHER (>2 IN HAIL)...WILL UP OUR OUTLOOK TO SIG OVER A DECENT PORTION OF THE NW. ELSEWHERE THE OUTLOOK WILL REMAIN SIMILAR AS STORMS MAY LOSE SOME POTENCY AS THEY PUSH FURTHER EAST AND GET LATER INTO THE OVERNIGHT. /CME/ LONG TERM...MONDAY THROUGH SATURDAY....MONDAY MORNING THE LARGE CLOSED LOW IS EXPECTED TO BE CENTERED OVER THE UPPER MISSISSIPPI VALLEY WITH ASSOCIATED LARGE AMPLITUDE UPPER LEVEL TROUGHING OVER THE EASTERN TWO THIRDS OF THE CONUS. MODELS AGREE THAT THE ASSOCIATED SURFACE LOW WILL BE OVER THE WESTERN GREAT LAKES REGION MONDAY MORNING BUT THERE ARE TIMING DIFFERENCES WITH THE TRAILING COLD FRONT THAT IS EXPECTED TO BE OVER SOUTHEAST MISSISSIPPI. CONSENSUS PLACES THIS COLD FRONT AND THE BULK OF THE PRECIPITATION JUST SOUTHEAST OF OUR CWA AT DAYBREAK BUT WL MAINTAIN LOW CHANCES OF LIGHT RAIN IN OUR NORTHEAST THROUGH MID MORNING AS A WEAK SHORTWAVE PASSES OVER OVERHEAD. DRY WEATHER IS EXPECTED AREAWIDE BY NOON. SLIGHTLY COOLER AND MUCH DRIER AIR WILL FILTER INTO OUR CWA MONDAY KNOCKING DEW POINTS INTO THE 40S DURING THE AFTERNOON. DRY WEATHER IS EXPECTED TO LAST OVER OUR CWA THROUGH TUESDAY AS A SURFACE HIGH MOVES EAST ACROSS OUR AREA. THIS SURFACE HIGH WILL SHIFT EAST WEDNESDAY AND THE RESULTING RETURN FLOW WILL INCREASE MOISTURE TO SUPPORT RAIN CHANCES AGAIN FROM THE WEST BY WEDNESDAY AFTERNOON. WARMER THAN NORMAL TEMPERATURES AND GREATER RAIN CHANCES ARE EXPECTED FOR THE END OF THE WEEK BUT THERE ARE SIGNIFICANT DIFFERENCES IN THE MODELS WITH SOME MAIN FEATURES. THE NORTHERN CLOSED LOW WILL MOVE SLOWLY EAST ACROSS THE GREAT LAKES REGION TUESDAY AND WEDNESDAY AND BE OVER THE NEW ENGLAND STATES BY FRIDAY. THIS LOW WILL TRY TO HELP SUPPORT ANOTHER COLD FRONT DROPPING INTO OUR CWA THURSDAY INTO FRIDAY BUT INDUCED SHORTWAVE RIDGING DOWNSTREAM OF A SECOND CLOSED LOW MOVING OVER THE DESERT SOUTHWEST THURSDAY LOOKS TO IMPEDE THE COLD FRONT INTO OUR AREA. SHORTWAVES ROUNDING THE BASE OF THE SOUTHERN CLOSED LOW LOOK TO COMBINE WITH INCREASING MOISTURE AND DAYTIME HEATING FOR A ROUND OF CONVECTION THURSDAY AND FRIDAY. BOTH GFS AND ECMWF OPEN THE CLOSED LOW AND BRING THE REMAINING SHORTWAVE TROUGH ACROSS OUR REGION SATURDAY BUT DIFFER ON THE SURFACE FEATURES WITH THE GFS DEPICTING A MUCH DEEPER LOW AND STRONGER COLD FRONT ACROSS OUR AREA. FOR NOW...GREATEST POPS THROUGH THE LONG TERM WILL BE CARRIED FRIDAY AND FRIDAY NIGHT. /22/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 75 64 81 61 / 83 66 31 39 MERIDIAN 76 65 82 64 / 73 78 37 34 VICKSBURG 73 64 81 59 / 87 53 34 46 HATTIESBURG 77 66 84 65 / 87 75 33 28 NATCHEZ 75 64 82 60 / 91 44 28 42 GREENVILLE 73 63 81 57 / 65 72 49 57 GREENWOOD 74 63 79 59 / 61 78 44 56 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ BB/15/EC/22
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
645 AM CDT Sat Apr 18 2015 .DISCUSSION... Issued at 411 AM CDT SAT APR 18 2015 Overview: Closed and cut-off upper low now over central CO will be the primary weather driver for the weekend. Feature will open up by Sunday and move east in response to a shortwave trough digging southeast through the Northern Rockies. Expect to see a several rounds of active convection Saturday and Sunday. Today - Sunday: While eyes have been fixated on the closed upper low now over CO/NM the real weather makers will be periodic vorticity lobes and associated layered frontogenesis that rotate northeast out from under the upper low. Little going on over the CWA early this morning as we`re lacking any discernible feature to initiate any convection. But we are finally seeing the long awaited next round of convection. Regional radars have recently lit up from OK northward through central KS albeit further west than we`ve been expecting. Favor following the HRRR reflectivity trends, which have slowed down the arrival of the KS/OK convection and latest NAM mass fields/h7 vorticity prog. Thus have pared back PoPs significantly for first part of morning and slowed the eastward expansion of precipitation. Even still this is a forecast which will need adjusting throughout the day as the convection tied to the upper low has had repeated false starts as well as expanding too fast to the east. Thickening cloud cover and rain-cooled air will affect temperatures over the western half of the CWA more so than the eastern half where precipitation will move in later in the day. Precipitable water values around two standard deviations above normal suggest potential for 1"+ rains through tonight. Weak shear and MUCAPEs under 1000J/kg favor convection remaining below severe limits. Should see a lull in the rain later tonight and first part of Sunday before the next wave of convection moves in. The upper low will have opened up by then and will accelerate eastward. Anticipate convection increasing as it moves east through the CWA in response to improving upper level dynamics and low-level convergence associated with a cold front. However, once again the 0-6km shear of 20-25kts and modest MUCAPEs favor convection being sub-severe. Monday - Tuesday: A fairly deep upper trough stretching from MN through the Mid MS Valley will influence our weather with widespread subsidence on the backside of the trough. Abundant solar insolation will help offset cold air advection but still result in below average temperatures. Wednesday - Friday: As the upper trough shifts east through the Great Lakes an upper ridge will build eastward through the Rockies and into the Central/Southern Plains. Medium range models are in agreement that a cold front will surge through the region on Wednesday. However, they disagree on whether or not convection will be generated. Moisture fields look minimal and believe any shower activity will be widely scattered. As we get into Thursday and Friday the ECMWF and GFS both lift a shortwave out of the southwestern U.S. but the GFS appears unrealistic in deepening a surface over the Central High Plains and spreading warm advection convection too far downstream. Will use a blended forecast but overall confidence low for Thursday`s PoPs but timing looks better for the PoPs on Friday. && .AVIATION...(For the 12Z TAFS through 12Z Sunday Morning) Issued at 641 AM CDT SAT APR 18 2015 A large area of showers and thunderstorms will evolve and lift north through eastern KS and western MO during the morning and afternoon hours. Generally VFR conditions with occasional MVFR cig/vsby restrictions with the stronger storms. Should see the rain temporarily end from west to east during the evening hours. Another band of showers and isolated storms may reach eastern KS and west central MO by the pre-dawn hours of Sunday morning with generally VFR conditions. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ DISCUSSION...MJ AVIATION...MJ
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
625 AM CDT SAT APR 18 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 328 AM CDT SAT APR 18 2015 SPC SUGGESTED SIGNIFICANT SEVERE WEATHER POTENTIAL THIS AFTERNOON AND EARLY THIS EVENING ACROSS PARTS OF SOUTHWEST AND NCNTL NEB. A PORTION OF THE LOW PRESSURE ACROSS SWRN KS THIS MORNING IS EXPECTED TO LIFT NORTHEAST THROUGH SCNTL AND ERN NEB THIS AFTERNOON SETTING UP A UNSTABLE WARM SECTOR FROM ROUGHLY IMPERIAL TO ONEILL. ALTHOUGH THE RAP IS FAIRLY QUIET THE NAM AND HRRR SBN MODELS SUGGEST REASONABLE POTENTIAL FOR CONVECTIVE DEVELOPMENT THIS AFTN IF SKIES PARTIALLY CLEAR ALLOWING FOR TEMPERATURES TO RISE INTO THE MID AND UPPER 60S. SATELLITE SHOWS CLEARING THIS MORNING ACROSS CNTL HIGH PLAINS OF KS/COLO AND IT IS BELIEVED THIS CLEARING WILL MOVE INTO SCNTL NEB THIS AFTN. THE STORM ACTIVITY COULD BEGIN AS EARLY AS 18Z IN THE SOUTHWEST WITH THE NAM SOLN OR AS LATE AS 21Z-00Z IN THE HRRR MODEL. SATELLITE TIMING TOOLS INDICATE THE CLEARING ACROSS KS COULD REACH SOUTHWEST NEB BY 13-15Z THIS MORNING WHICH WOULD PROVIDE A GOOD START FOR MODEST HEATING GIVEN THAT THIS CLEARING AREA WOULD TEND TO FILL IN WITH DEVELOPING CUMULUS. ONE WEAKNESS ARE THE WIND FIELDS 500MB AND BELOW WHICH ARE LIGHT PRODUCING BULK SHEAR VALUES OF 30KT OR LESS WHICH MIGHT SUPPORT MORE OF HEAVY RAIN THREAT. STILL TEMPERATURES ALOFT WILL BE VERY COLD AS THE H500MB LOW ACROSS COLO MOVES EAST TO NEAR LIMON/SPRINGFIELD. WINDS AT 300MB ARE STRONG NEAR 65KT POTENTIALLY ENHANCING UPDRAFTS AND PROVIDING VENTILATION. FREEZING LEVELS ARE NEAR 5KFT SUPPORTING A LOW TOP STORM ENVIRONMENT AND GOOD POTENTIAL FOR HAIL. THE NAM IS PRODUCING AROUND 2000 J/KG OF CAPE AT NORTH PLATTE AND BROKEN BOW WHILE THE RAP AND OTHER MODELS SHOW HALF OR LESS THAT VALUE. NORTHWEST WINDS WILL SWEEP IN FROM THE WEST IN THE WAKE OF THE DISTURBANCE TONIGHT. THIS SHOULD PRODUCE DRYING AND DECREASING RAIN CHANCES FROM MIDNIGHT ONWARD. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 328 AM CDT SAT APR 18 2015 SUNDAY WILL SEE THE STRONG LOW PRESSURE WEAKENING AS IT PUSHES EAST WHILE A TROUGH DIGS ACROSS THE CANADIAN PLAINS. SOME LINGERING SUNDAY MORNING SHOWERS ARE POSSIBLE IN THE EASTERN ZONES...HOWEVER THE BIGGER EVENTS OF THE DAY WILL BE THE CAA AND INCREASING NW WINDS. AS THE LOW PUSHES ACROSS KS...DRY AIR WILL QUICKLY FILL IN BEHIND...RESULTING IN DECREASING CLOUDS FROM WEST TO EAST IN THE MORNING. BY AFTERNOON SHOULD SEE MOSTLY SUNNY SKIES FOR ALL. THE SUN WILL COMBINE WITH THE STRONG NW WINDS /GUSTING TO 30 TO 40 MPH/ TO PROMOTE GOOD MIXING OF THE BL AND OFFSET THE CAA AND TEMPS PUSH INTO THE 50S. EARLY IN THE WEEK THE TROUGH DIGS TOWARDS THE GREAT LAKES REGION AND ABSORBS THE SOUTHERN LOW. ELONGATED SFC HIGH PRESSURE BUILDS ACROSS THE HIGH PLAINS. THE ACTIVE WEATHER IS WELL TO THE NE ALTHOUGH A FEW UPPER LEVEL DISTURBANCES WILL RIDE ALONG THE NW FLOW OVERHEAD AND BRING SOME PASSING CLOUDS AT TIMES. LIMITED MOISTURE IN THE LOWER LEVELS AND MODELS/FORECAST ARE DRY. TEMPS TO START THE WEEK WILL BE CHILLY IN THE MORNING WITH MOST AREAS NEAR OR BELOW THE FREEZING MARK. STILL A COUPLE OF WEEKS FROM TYPICAL LAST FREEZE FOR MOST OF THE AREA...SO NO HEADLINES NEEDED YET. HIGHS REBOUND NICELY WITH A WARMING TREND WITH 60S MAYBE 70 FOR WED AND THURS. EYES THEN FOCUS ON A TROUGH AS IT DIGS ACROSS THE SOUTHWEST. MODELS IN GOOD AGREEMENT DEVELOPING A CLOSED 500 MB LOW NEAR SRN CAL BY THURS. THE LOW THEN LIFTS TOWARDS THE 4 CORNERS WHILE BECOMING AN OPEN WAVE. THE WAVE WILL THEN PUSH ACROSS THE PLAINS TO END THE WEEK. THIS WILL BRING A RETURN OF THE ACTIVE WEATHER...AND WILL HAVE POPS TOWARDS THE END OF THE EXTENDED PERIOD. STILL HAVE SOME LOCATION AND TIMING ISSUES TO IRON OUT WHICH IS TYPICAL THIS FAR OUT SO POPS KEPT BELOW 50 PERCENT FOR NOW. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 625 AM CDT SAT APR 18 2015 MIXED FLIGHT CONDITIONS CONTINUE TODAY. VFR IS EXPECTED THIS MORNING ACROSS SWRN/SCNTL NEB AS A CLEAR SLOT MOVES IN FROM THE SOUTH. THIS AREA OF CLEARING WILL WARM UP AND DESTABLIZE THIS AFTN WITH SCATTERED SHRA/TSTM COVERAGE DEVELOPING 18Z-21Z AND CONTINUING THROUGH ABOUT 03Z THIS EVENING. STORMS WHICH DEVELOP WILL LIKELY LIFT NORTH TOWARD KVTN THIS EVENING AROUND 03Z-06Z. A COLD FRONT WILL SWEEP INTO THE FCST AREA FROM THE NORTHWEST TONIGHT BETWEEN 03Z-09Z PRODUCING MVFR CIGS AND SCATTERED SHOWERS. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...CDC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
646 AM EDT SAT APR 18 2015 .SYNOPSIS... WEAKENING LOW PRESSURE OFFSHORE AND AN APPROACHING DISTURBANCE ALOFT FROM THE WEST WILL MAINTAIN SCATTERED SHOWERS TODAY. A WARM FRONT WILL LIFT NORTH ACROSS THE AREA SUNDAY AND SUNDAY NIGHT BRINGING WIDESPREAD SHOWERS AND THUNDERSTORMS. THIS WILL BE FOLLOWED BY A COLD FRONT MONDAY NIGHT...WITH DRY AND SEASONABLE HIGH PRESSURE TO FOLLOW THROUGH THE MIDDLE OF THE UPCOMING WEEK. THIS HIGH PRESSURE WILL MOVE OFFSHORE THURSDAY BRINGING A RETURN TO ABOVE NORMAL TEMPERATURES. && .NEAR TERM /THROUGH TONIGHT/... AS OF 645 AM SATURDAY...THE ONLY TWEAKS TO THE FORECAST THIS MORNING ARE TO INCREASE POPS TO 80-100 PERCENT ALONG AND EAST OF I-95 FOR THE LARGE AREA OF RAIN AND EMBEDDED CONVECTIVE SHOWERS MOVING EAST TOWARD THE COAST. LATEST HRRR AND HRRRX MODELS SHOW THIS ACTIVITY MOVING OFF THE COAST BY 15Z-16Z (11 AM TO NOON) WITH SCATTERED SHOWERS REDEVELOPING FARTHER INLAND FOR THE AFTERNOON. DISCUSSION FROM 300 AM FOLLOWS... A VERY NEBULOUS SURFACE PRESSURE PATTERN EXISTS ACROSS THE CAROLINAS. WEAK LOW PRESSURE DEVELOPED A COUPLE DAYS AGO ALONG AN OLD STALLED FRONT NEAR SAVANNAH. THIS LOW IS NOW DISSIPATING WELL EAST OF THE SOUTH CAROLINA COAST DUE TO LACK OF BAROCLINICITY. THIS WILL LEAVE VIRTUALLY NO SURFACE FEATURES OF NOTE TODAY...LEAVING WINDS AT THE MERCY OF LOCAL EFFECTS LIKE THE AFTERNOON SEABREEZE CIRCULATION PLUS ANY SHOWER OUTFLOW BOUNDARIES. AN UPPER LEVEL DISTURBANCE IS MOVING EASTWARD ACROSS THE CAROLINAS THIS MORNING. THIS FEATURE SHOULD BRING GOOD CHANCES OF SHOWERS... ESPECIALLY TO COASTAL SOUTH CAROLINA...WITH PRECIPITATION COVERAGE EXPECTED TO DECREASE MARKEDLY IN THE FIRST FEW HOURS AFTER DAYBREAK. STRONG APRIL SUNSHINE WILL CUT THROUGH THE REMAINING CLOUD COVER AND HIGHS SHOULD STILL APPROACH 80 INLAND...WITH MID 70S NEAR THE COAST. ALTHOUGH PRECIPITATION CHANCES MAY NOT INCREASE APPRECIABLY DURING THE AFTERNOON AT THE COAST...TEMPS NEAR 80 SHOULD TRIGGER SCATTERED SHOWERS INLAND WITH COVERAGE PROBABLY AROUND 30 PERCENT. ANOTHER UPPER DISTURBANCE WILL APPROACH THE EASTERN CAROLINAS VERY LATE TONIGHT FROM THE SOUTHWEST. HIGH PRESSURE OVER SE CANADA WILL BEGIN TO BUILD DOWN THE EASTERN SEABOARD LATE TONIGHT AS WELL...WITH A BACKDOOR COLD FRONT APPROACHING THE AREA FROM THE NORTHEAST AROUND SUNRISE SUNDAY. LOWS SHOULD FALL INTO THE LOWER TO MIDDLE 60S. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY...STILL SHAPING UP TO BE A VERY WET PERIOD FOR THE SHORT TERM AHEAD OF A COLD FRONT WHICH WILL CROSS THE AREA MONDAY NIGHT. SUNDAY WILL BEGIN DRY ACROSS MOST OF THE AREA...BUT THIS WILL QUICKLY CHANGE AS A LOW PRESSURE SYSTEM BENEATH A POTENT SHORTWAVE DEVELOPS AND MOVES OUT OF THE GULF STATES AND INTO THE OHIO VLY. A WARM FRONT AHEAD OF THIS FEATURE WILL MOVE OVERHEAD THE CAROLINAS...WITH A SECONDARY AREA OF LOW PRESSURE POSSIBLY DEVELOPING OVERHEAD LATE SUNDAY NIGHT. DEEP SW FLOW WILL INTENSIFY LATE SUNDAY...WITH 850MB V-WIND COMPONENT REACHING +3 SD`S LATE SUNDAY NIGHT...SUPPORTING AN ENVIRONMENT OF POTENTIALLY RECORD-FOR- THE-DAY PRECIPITABLE WATER AS COMPARED AGAINST THE SPC SOUNDING CLIMATOLOGY. ALTHOUGH A NICE SUBTROPICAL JET WILL ARC ACROSS THE MEXICO/US BORDER SUNDAY NIGHT...THIS WILL NOT AID IN ANY LIFT SO UPPER SUPPORT LOOKS TO BE PRETTY WEAK INVOF THIS SYSTEM. HOWEVER...SURFACE CONVERGENCE NEAR THE LOW PRESSURE COMBINED WITH STRONG LOW-LEVEL MOISTURE TRANSPORT...WARM CLOUD DEPTH OF 11-12 KFT...AND ONLY WEAK INSTABILITY WHICH PROVIDES LONG PARCEL RESIDENCE TIMES WITHIN THE SATURATED COLUMN...SUGGEST PERIODS OF HEAVY RAINFALL WILL OCCUR...ESPECIALLY SUNDAY NIGHT. INSTABILITY LOOKS PRETTY LIMITED SO THUNDER WILL BE ONLY ISOLATED...BUT HEAVY SHOWERS PRODUCING WIDESPREAD 1" OF QPF OR MORE LOOKS VERY LIKELY INTO MONDAY MORNING. MUCH DRIER AIR WILL FILTER INTO THE REGION MONDAY...BUT CONTINUED DEEP SW FLOW AND THE APPROACH OF A COLD FRONT WILL STILL CREATE THE POTENTIAL FOR SCATTERED SHOWERS. BEST CHANCE WILL BE LATE MONDAY INTO MONDAY NIGHT IMMEDIATELY AHEAD OF AND ALONG THE BOUNDARY...WHICH IS PROGGED TO MOVE OFFSHORE BY THE END OF THE PERIOD. TEMPS THROUGH THE PERIOD WILL BE NORMAL-TO-ABOVE FOR MID-APRIL. MONDAY WILL BE THE WARMER DAY WITH FEWER CLOUDS ALLOWING FOR MORE INSOLATION TO WARM THE SURFACE. 850MB TEMPS BOTH DAYS WILL BE 12- 14C...BUT CLOUDS AND RAIN WILL KEEP HIGHS IN THE MID 70S SUNDAY...WARMING INTO THE LOW 80S AWAY FROM THE COAST MONDAY. LOWS SUNDAY NIGHT WILL STRUGGLE TO DROP ONLY INTO THE UPR 60S...LOW 60S BEHIND THE FRONT MONDAY NIGHT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY...COLD FRONT WILL BE OFFSHORE TUESDAY MORNING...AND A PRIMARILY QUIET WEEK LOOKS TO BE ON TAP FOR THE EXTENDED. HIGH PRESSURE WILL MOVE ACROSS THE SOUTHERN TIER OF STATES TUE-THU BEFORE PUSHING OFFSHORE LATE IN THE WEEK. THIS OCCURS IN RESPONSE TO FORCED-ZONAL FLOW SOUTH OF A LARGE CLOSED LOW WHICH WILL SIT AND SPIN ACROSS SE CANADA THROUGH MUCH OF THE WEEK. THE CAROLINAS WILL BE ON THE PERIPHERY OF THIS FEATURE...SO WHILE COOLER TEMPS WILL OCCUR TUE/WED...SEASONABLE VALUES ARE ANTICIPATED. LATE IN THE PERIOD AS THE HIGH PUSHES OFFSHORE...MOIST RETURN FLOW WILL DEVELOP AND SHOWER ACTIVITY WILL BECOME POSSIBLE ONCE AGAIN THURSDAY...AND ESPECIALLY FRIDAY. FRIDAY WILL FEATURE THE BEST CHANCES FOR PRECIP BOTH DUE TO INCREASED COLUMN MOISTURE...BUT ALSO THANKS TO A COLD FRONT WHICH WILL APPROACH FROM THE NW...DRIVEN BY A PIECE OF VORT ENERGY ROTATING AROUND THE AFOREMENTIONED LARGE UPPER LOW. TEMPS THU/FRI WILL RETURN TO ABOVE NORMAL HOWEVER. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 12Z...A RATHER LARGE BATCH OF PRECIP IS CURRENTLY PASSING THROUGH THE CWA FROM WEST TO EAST...ASSOCIATED WITH A SHORT WAVE. LOOK FOR INTERMITTENT MVFR WITH POSSIBLE BRIEF IFR PERIODS IN THE HEAVIER PRECIP. THE SHORTWAVE AND ASSOCIATED PRECIP WILL EXIT THE REGION BY LATE MORNING...HOWEVER IT IS LIKELY THAT MVFR CEILINGS WILL REMAIN FOR SOME TIME AFTER THAT. HIGH PRESSURE CENTERED TO OUR NORTH WILL GIVE US LIGHT NORTHEAST FLOW TODAY. THROUGH THE EVENING HOURS MAINLY A MID CLOUD CEILING WILL PREVAIL. EXTENDED OUTLOOK...SHOWERS ACCOMPANIED WITH ISOLATED THUNDER TO AFFECT THE FORECAST AREA LATE SUNDAY THROUGH MONDAY MORNING...RESULTING IN OCCASIONAL MVFR AND IFR CONDITIONS. SCATTERED PCPN ASSOCIATED WITH A CFP MONDAY NIGHT FOLLOWED BY MAINLY VFR CONDITIONS TUE THROUGH WED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 645 AM SATURDAY...ADJUSTED FORECAST WIND DIRECTIONS 20-30 DEGREES COUNTERCLOCKWISE FOR THE NEXT 3-4 HOURS BASED ON CURRENT OBSERVATIONS...OTHERWISE NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE FORECAST. DISCUSSION FROM 300 AM FOLLOWS... A VERY DISORGANIZED SURFACE WEATHER PATTERN EXISTS ACROSS THE AREA. WEAK LOW PRESSURE THAT DEVELOPED A COUPLE DAYS AGO ALONG AN OLD STATIONARY FRONT IS DISSIPATING OFF THE SOUTH CAROLINA COAST. MORE IMPORTANT TO OUR WEATHER WILL BE THE PASSAGE OF AN UPPER LEVEL DISTURBANCE THIS MORNING WHICH PROMISES TO BRING GOOD CHANCES FOR SHOWERS. BEHIND THIS DISTURBANCE LOOK FOR PARTIAL CLEARING AND A REDUCTION IN RAIN COVERAGE FOR THE AFTERNOON. BY LATE TONIGHT THE APPROACH OF ANOTHER DISTURBANCE FROM THE SOUTHWEST COULD BRING INCREASING SHOWER CHANCES IN AROUND DAYBREAK. VARIABLE WINDS TODAY SHOULD REMAIN 10 KNOTS OR LESS. SEAS AS HIGH AS 4 FEET IN THE 10-20 MILE OFFSHORE WATERS NEAR CAPE FEAR WILL SUBSIDE THIS AFTERNOON...WITH 2-3 FEET SEAS EXPECTED FOR ALL AREAS. VERY LATE TONIGHT HIGH PRESSURE OVER SE CANADA WILL PUSH A BACKDOOR FRONT TOWARD THE AREA...WITH INCREASING NE WINDS EXPECTED AROUND DAYBREAK SUNDAY. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY...STRENGTHENING SOUTHERLY FLOW AHEAD OF A COLD FRONT WILL PRODUCE GUSTY WINDS AND A POSSIBLE SHORT SCA SUNDAY NIGHT INTO MONDAY. BEFORE THIS TIME...WINDS WILL VEER FROM E TO S THROUGH SUNDAY AS HIGH PRESSURE MOVES OFF TO THE NE AND A WARM FRONT LIFTS ACROSS THE WATERS. AS THE WINDS VEER THEY WILL INCREASE AS WELL...BECOMING 15-20 KTS SUNDAY NIGHT INTO MONDAY...AND THESE WINDS WILL PUSH SEAS UP TO 3-6 FT...HIGHEST ACROSS THE NC WATERS. A SHORT DURATION SCA STILL LOOKS LIKELY AND IS HIGHLIGHTED IN THE HWO. WINDS WILL SLOWLY VEER THROUGH MONDAY TO THE SW AT SIMILAR SPEEDS...BEFORE THE COLD FRONT CROSSES THE WATERS AT THE END OF THE PERIOD WITH A WIND SHIFT TO THE NW. SEAS MONDAY WILL BE 3-5 FT AHEAD OF THE COLD FRONT...BEFORE FALLING AS THE WINDS TURN OFFSHORE LATE. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 300 AM SATURDAY...HIGH PRESSURE MOVING ACROSS THE SOUTHERN TIER OF THE NATION WILL DRIFT ACROSS THE WATERS DURING WEDNESDAY. AHEAD OF THIS...LIGHT NW WINDS WILL OCCUR OVER THE WATERS...BECOMING VARIABLE WEDNESDAY AS THE GRADIENT WEAKENS...AND EVENTUALLY TURNING TO THE SW LATE...BUT STILL AT SPEEDS GENERALLY 10 KTS OR LESS. A VERY BRIEF PERIOD OF 3-5 FT SEAS ARE POSSIBLE EARLY TUESDAY...LEFTOVERS FROM THE MORE STRONGLY FORCED SEAS ON MONDAY...BEFORE FALLING TO 2-3 FT AND PERSISTING THROUGH MID-WEEK. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...TRA SHORT TERM...JDW LONG TERM...JDW AVIATION...DL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
921 AM CDT SAT APR 18 2015 .UPDATE... ISSUED AT 920 AM CDT SAT APR 18 2015 WILL CONTINUE TO FAVOR THE TRENDS OF THE 10-13 UTC HRRR ITERATIONS WHICH KEEP THE BAND OF PRECIPITATION ACROSS SOUTHERN SOUTH DAKOTA AND EASTERN NEBRASKA IN ASSOCIATION WITH THE UPPER LEVEL LOW FOR THE MOST PART TO THE SOUTH OF NORTH DAKOTA UNTIL 22-24 UTC THIS EVENING GIVEN DRY EAST-SOUTHEASTERLY LOW LEVEL FLOW PRECEDING THIS SYSTEM. BETTER CHANCES FOR SHOWER ACTIVITY THIS AFTERNOON ARE ACROSS THE WEST AS A COLD FRONT ACROSS EASTERN MONTANA THIS MORNING ENTERS WESTERN NORTH DAKOTA THIS AFTERNOON. DID ADD A MENTION OF THUNDERSTORMS TO THE WEST ALONG THE FRONT WITH SOME WEAK INSTABILITY DEPICTED ON THE 06 UTC NAM/GFS BUFR SOUNDINGS. UPDATE ISSUED AT 626 AM CDT SAT APR 18 2015 A FEW WEAK RADAR ECHOS ARE TRYING TO SNEAK INTO THE SOUTH CENTRAL PART OF THE STATE...THOUGH THESE APPEAR WEAK AND DOUBTFUL MORE THAN A FEW SPRINKLES COULD BE HITTING THE GROUND. WITH THAT SAID...LATEST GUIDANCE IS STILL ON TRACK FOR SHOWERS TO BE ON THE INCREASE LATE DAY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 424 AM CDT SAT APR 18 2015 MARGINAL FIRE WEATHER CONDITIONS AND CHANCES FOR MUCH NEEDED RAIN WILL HIGHLIGHT THE SHORT TERM. AS TWO UPPER LEVEL LOWS CONVERGE OVER THE NORTHERN PLAINS THROUGH SATURDAY...MOISTURE TRANSPORT FROM THE SOUTH AND ATMOSPHERIC INSTABILITY WILL CREATE WIDESPREAD CHANCES FOR RAIN. SOUTHERN AND EASTERN AREAS OF THE STATE ARE EXPECTED TO HAVE THE GREATEST CHANCES FOR SUBSTANTIAL RAIN...CONCLUDED THROUGH GOOD AGREEMENT WITH THE CURRENT 00Z MODEL SUITE. CHANCES FOR RAIN ARE FORECAST TO INITIATE THROUGH SATURDAY AFTERNOON AND PERSIST INTO SUNDAY MORNING. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 424 AM CDT SAT APR 18 2015 ON SUNDAY...DEEPENING TROUGH CLOSES OFF OVER MANITOBA WHILE LOW OVER THE SOUTHERN PLAINS WASHES INTO THE NORTHERN SYSTEM. PRECIPITATION CHANCES WILL CONTINUE PRIMARILY OVER CENTRAL AND NORTHERN NORTH DAKOTA...THOUGH MOISTURE WRAPPING AROUND THE BACK SIDE OF THE SYSTEM WILL STILL KEEP LOWER PRECIPITATION CHANCES FURTHER SOUTH AND WEST. GUSTY WINDS EXPECTED THOUGH THE DAY IN TIGHT PRESSURE GRADIENT WITH SURFACE LOW PUSHING INTO THE MIDWEST. WINDS WILL REMAIN BREEZY OVERNIGHT WITH LOW RAIN/SNOW CHANCES LINGERING OVER CENTRAL NORTH DAKOTA. UPPER LOW PUSHES ALONG THE MINNESOTA/ONTARIO BORDER ON MONDAY. THIS WILL KEEP LOW PRECIPITATION CHANCES GOING PRIMARILY OVER THE JAMES RIVER VALLEY. WITH TIGHT PRESSURE GRADIENT ON THE BACK SIDE OF THIS SYSTEM...WILL KEEP THE STRONGER WINDS MAINLY OVER CENTRAL NORTH DAKOTA...DECREASING TOWARDS THE WEST. 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 A FEW SHOWERS POSSIBLE ON TUESDAY AS A FAST MOVING WAVE SLIDES THROUGH THE FLOW...DRY WEATHER IS EXPECTED. TEMPERATURES WILL REMAIN A BIT BELOW AVERAGE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 918 AM CDT SAT APR 18 2015 A COLD FRONT ACROSS EASTERN MONTANA THIS MORNING WILL ENTER WESTERN NORTH DAKOTA THIS AFTERNOON AND MERGE WITH A LOW DEVELOPING ACROSS EASTERN SOUTH DAKOTA TONIGHT. SCATTERED RAIN SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS WESTERN NORTH DAKOTA THIS AFTERNOON...WITH MORE WIDESPREAD RAIN SHOWERS POSSIBLE AT KMOT/KBIS/KJMS THIS EVENING AND TONIGHT. EMBEDDED MVFR CONDITIONS POSSIBLE IN RAIN. && .FIRE WEATHER... ISSUED AT 424 AM CDT SAT APR 18 2015 RELATIVE HUMIDITY VALUES ARE PROJECTED TO BE IN THE LOWER TO MID 20S THIS AFTERNOON OVER CENTRAL NORTH DAKOTA. WITH SOUTHERLY WINDS OF AROUND 10 TO 20 MPH...NEAR CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE. OVER WESTERN NORTH DAKOTA...A COLD FRONT WILL PUSH INTO THE AREA BRINGING A WIND SHIFT TO THE NORTHWEST. BEHIND THE FRONT...WINDS WILL INCREASE TO AROUND 25 MPH. RELATIVE HUMIDITY VALUES WILL BE HIGHER OVER THIS REGION...INCREASING BEHIND THE FRONT...THOUGH THIS STILL MAY BRING A PERIOD OF NEAR CRITICAL FIRE WEATHER CONDITIONS. WETTING RAINS POSSIBLE TONIGHT...ESPECIALLY OVER THE EASTERN HALF OF THE STATE. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...AC LONG TERM...JJS AVIATION...AYD FIRE WEATHER...AC/JJS
AREA FORECAST DISCUSSION
NWS NORMAN OK
646 AM CDT SAT APR 18 2015 .DISCUSSION... AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW. && .AVIATION... HAVE LOW CONFIDENCE OF VFR TO LIFR CONDITIONS IN WESTERN OKLAHOMA THROUGH 21Z AS WELL AS LOW CONFIDENCE WITH TSRA TIMING/COVERAGE AFTER 19Z. CONDITIONS WILL BOUNCE BETWEEN VFR AND LIFR WITH BR/FG ACROSS WESTERN OKLAHOMA THROUGH 21Z. THE WORST CONDITIONS MAY BE NEAR KCSM AND KHBR THROUGH 15Z. IFR CONDITIONS MAY AFFECT KSPS AND KLAW AS WELL THROUGH 15Z...BUT DID NOT MENTION THINKING THESE LOWER CONDITIONS WILL STAY WEST OF THESE SITES. HAVE HIGH CONFIDENCE ALL SITES WILL BE VFR BY 21Z. ISO-NUM TSRA WILL FORM AND AFFECT MANY TAF SITES AFTER 19Z. USED VCTS/TEMPOS AT MOST SITES EXCEPT KCSM AND KHBR WHERE CONFIDENCE OF STORMS IS TOO LOW TO MENTION. BRIEF VARIABLE GUSTY WINDS... HAIL...AND MVFR OR LOWER CONDITIONS ARE POSSIBLE WITH THE STRONGEST STORMS. MOST STORMS WILL BE EAST OF ALL TAF SITES BY 04Z. ADDITIONAL MVFR/IFR CONDITIONS MAY DEVELOP AFTER 06Z BUT DID NOT MENTION DUE TO LOW CONFIDENCE OF OCCURRENCE. MBS && .PREV DISCUSSION... /ISSUED 419 AM CDT SAT APR 18 2015/ DISCUSSION... SEVERE THUNDERSTORM POTENTIAL THIS AFTERNOON AND EVENING IS THE MAIN CONCERN. RAIN CHANCES THIS MORNING LOOK TO BE MAINLY CONFINED TO LOCATIONS EAST OF I-35 WHERE MOST LATEST RADAR ECHOES WERE OCCURRING FROM A WEAK IMPULSE ROTATING AROUND A MID/UPPER LOW IN SOUTHERN COLORADO. NO SEVERE STORMS ARE EXPECTED WITH THIS ACTIVITY...JUST SOME LOCALIZED HEAVY RAIN. MOST OF THIS ACTIVITY MAY END BY 8 AM IF THE LATEST HRRR RUNS ARE CORRECT. MOST LOCATIONS WILL REMAIN DRY THIS MORNING. ADDED PATCHY FOG MENTION THROUGH 11 AM THIS MORNING ACROSS PARTS OF WESTERN OKLAHOMA AND WESTERN NORTH TEXAS WHERE SOME PARTIAL CLEARING...ABUNDANT LOW LEVEL MOISTURE...AND LATEST HRRR RUNS FAVOR SOME DEVELOPMENT. DOUBT IT WILL GET TOO WIDESPREAD OR DENSE. THIS AFTERNOON AND EVENING...ISOLATED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE AREA. CAPPING WILL BE RATHER WEAK. WITH MORE SUN COMPARED TO YESTERDAY...THINK CONVECTIVE TEMPERATURES WILL BE REACHED RATHER EASILY IN THE 2 TO 5 PM TIME FRAME. FIRST DEVELOPMENT MAY BE FOCUSED IN WESTERN OKLAHOMA AND WESTERN NORTH TEXAS NEAR A DEVELOPING DRYLINE. WENT NEAR GUIDANCE RAIN CHANCES. EXACTLY WHERE AND WHEN STORMS OCCUR REMAINS TRICKY TODAY AND TONIGHT. IN REGARDS TO SEVERE POTENTIAL THIS AFTERNOON AND EVENING... BELIEVE THERE WILL BE SOME SEVERE STORMS WITH LARGE HAIL AS THE MAIN CONCERN. THE AIR WILL BE MODERATELY UNSTABLE WITH MLCAPE 1500-2500 J/KG. STRONG 0-6 KM SHEAR 30-50 KT SUPPORTS SUPERCELLS AND MULTICELLS. STRONG 0-3 KM SHEAR VALUES 25-45 KT AND VERY COLD MID LEVELS WITH 500 MB TEMPERATURES AROUND -18C COULD SUPPORT VERY LARGE HAIL IN SOME CELLS AS LONG AS CONVECTION IS NOT TOO WIDESPREAD. SOME DAMAGING WINDS MAY OCCUR AS WELL IF STORMS CAN ORGANIZE INTO CLUSTERS AND LINES. TORNADO POTENTIAL APPEARS TO BE LIMITED DUE TO WEAK LOW LEVEL SHEAR...THOUGH NOTICED THE LATEST RAP13 INDICATED STRONGER LOW LEVEL WINDS POSSIBLY DEVELOPING IN SOUTHWESTERN OKLAHOMA IN THE 5 TO 9 PM TIME FRAME WHICH MAY INCREASE THIS POTENTIAL. WILL CLOSELY MONITOR. LOCALLY HEAVY RAINFALL MAY AGAIN OCCUR LATE THIS AFTERNOON AND TONIGHT...THOUGH STORM MOTIONS WILL BE FASTER WHICH MAY LIMIT THE DURATION OF HEAVY RAINFALL IN ONE GIVEN LOCATION. MOST STORMS WILL MOVE INTO EASTERN OKLAHOMA AFTER MIDNIGHT TONIGHT...ALLOWING FOR MOIST AND COOL CONDITIONS. WOULD NOT BE SURPRISED IF SOME FOG FORMED...BUT DID NOT MENTION DUE TO LOW CONFIDENCE. ON SUNDAY...A FEW SHOWERS AND STORMS MAY LINGER MAINLY OVER NORTHERN OKLAHOMA...THOUGH APPEARS THE SEVERE POTENTIAL WILL SHIFT IN FAR EASTERN OKLAHOMA AND POINTS EAST. WITH LINGERING WEAK INSTABILITY AND COLD MID/UPPER LEVELS...A FEW STORMS WITH SMALL HAIL COULD OCCUR. BREEZY CONDITIONS WILL DEVELOP. THERE IS AN OUTSIDE CHANCE WINDS COULD APPROACH ADVISORY CRITERIA WITH GUSTS OVER 40 MPH IN NORTHWEST OKLAHOMA. WENT WITH THE WARMER SIDE OF GUIDANCE TEMPERATURES THINKING SOME SUN WILL OCCUR...ESPECIALLY EARLY IN THE DAY. SUNDAY NIGHT THROUGH FRIDAY...A WET PATTERN MAY CONTINUE WITH RAIN CHANCES REMAINING IN THE FORECAST MOST DAYS. THERE ARE SOME MODEL DISCREPANCIES WITH WEATHER FEATURES...THUS FORECAST CONFIDENCE REMAINS LOW. SOME STRONG TO SEVERE STORMS MAY OCCUR TUESDAY THROUGH FRIDAY WITH NEARBY MOISTURE AND INSTABILITY. MBS && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 25/17/17
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
1040 AM CDT SAT APR 18 2015 .UPDATE... ISSUED AT 1030 AM CDT SAT APR 18 2015 WITH DRY AIR IN PLACE...ERODING NORTHERN EXTENT OF SHOWER ACTIVITY...REDUCED POPS/QPF NORTH OF THE MAIN BAND OF PRECIPITATION FOR THE AFTERNOON IN LINE WITH LATEST HRRR AND RUC GUIDANCE. LATEST NAM IS IN LINE WITH CURRENT FORECAST AFTER 00Z. HRRR COLUMN MAX REF DOES LOOK LIKE A WEAK FEW CONVECTIVE CELLS FORM OVER THE CWA TODAY SO WILL LEAVE MENTION OF THUNDER IN. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 327 AM CDT SAT APR 18 2015 PRECIPITATION CHANCES OVER THE NEXT 24 HOURS...AND WINDS SUNDAY AND MONDAY WILL BE THE FORECAST CHALLENGES. A FAIRLY DRY AIR MASS REMAINS IN PLACE ACROSS MOST OF THE CWA THIS MORNING WITH DEW POINTS MAINLY IN THE UPPER 20S. HIGHER DEW POINTS ARE ADVECTING NORTHWESTWARD INTO WESTERN SOUTH DAKOTA WHERE VALUES IN THE 40S. THESE HIGHER DEW POINTS...ALONG WITH SOME SHOWERS AND THUNDERSTORMS WILL SLOWLY TRACK NORTHWARD THROUGH THE DAY AS AN UPPER LEVEL LOW PRESSURE SYSTEM MOVES ACROSS THE CENTRAL PLAINS. VARIOUS HI-RES MODELS SUGGEST SHOWERS WOULD REACH HIGHWAY 212 AROUND 18Z...AND HIGHWAY 12 BETWEEN 21-0Z THIS AFTERNOON. HAVE TRIED TO DELAY POPS IN THE NORTHERN AND FAR NORTHEASTERN PORTION OF THE CWA UNTIL AFTER 21Z. PCPN MAY NOT REACH THE SISSETON/WHEATON AREA UNTIL AFTER 0Z SUNDAY. TONIGHT THROUGH SUNDAY MORNING...MODELS SUGGEST THE LOW PRESSURE SYSTEM WILL MERGE WITH A NORTHERN STREAM TROUGH...WHICH COULD BRING BETTER CHANCES FOR SHOWERS. THE NORTHERN STREAM WILL LIKELY BRING GUSTY NORTHWESTERLY WINDS TONIGHT ALONG A SURFACE COLD FRONT. A FAIRLY DRY AIR MASS WILL FOLLOW THIS COLD FRONT WITH PCPN LIKELY ENDING FROM WEST TO EAST BY THE MID MORNING HOURS ON SUNDAY. BY SUNDAY AFTERNOON COLD AIR ADVECTION WILL DEVELOP WITH GUSTY NORTHWESTERLY WINDS AND INSTABILITY SHOWERS POSSIBLE. WINDS MAY EXCEED ADVISORY LEVELS...ESPECIALLY IN THE WESTERN HALF OF THE CWA. A TIGHT PRESSURE GRADIENT OVER THE REGION WILL PROMOTE GUSTY NORTHWESTERLY WINDS ON MONDAY AS WELL. COLD AIR ALOFT...ALONG WITH CAPE VALUES AROUND 100 J/KG COULD PRODUCE ISOLATED SHOWERS IN THE FAR EASTERN PORTION OF THE CWA MONDAY AFTERNOON. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 327 AM CDT SAT APR 18 2015 NOT MUCH CHANGE NOTED IN THE LONGER RANGE MODEL OUTPUT...COMPARED TO 24 HOURS. PRECIPITATION CHANCES ARE PRETTY MUCH DONE AND GONE MONDAY NIGHT...WITH A MAINLY DRY FORECAST THERE-AFTER /DRY AND COOL NORTHWEST FLOW ESTABLISHING OVER THE NORTHERN PLAINS ALOFT/. BY THURSDAY...THERE IS A RATHER SLIM CHANCE THAT ENERGY TRYING TO LIFT NORTH-NORTHEAST TOWARD THE NORTHERN PLAINS COULD INTRODUCE SOME DEFORMATION ZONE-FORCED LIGHT PRECIP POTENTIAL ACROSS THE SOUTHWESTERN FORECAST ZONES...PRIOR TO EXPERIENCING THE SHEARING EFFECTS OF NORTHWEST /POLAR JET/ FLOW ALOFT. SUPERBLEND CONTINUES TO PRODUCE SOME LOW PROBABILITIES FOR PRECIPITATION THURSDAY NIGHT/FRIDAY THOUGH. UNDER THIS NORTHWEST FLOW ALOFT REGIME...LOW LEVEL FLOW IS PERSISTENTLY ADVECTING COOL/DRY AIR DOWN OUT OF CANADA ON NORTHEASTERLY BOUNDARY LAYER MIXING WINDS. TEMPERATURES DURING THE EXTENDED FORECAST PERIOD SHOULD BE RUNNING NEAR NORMAL TO PERHAPS A FEW DEGREES BELOW NORMAL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 651 AM CDT SAT APR 18 2015 VFR CONDITIONS ARE EXPECTED THROUGH THE FIRST PART OF TODAY AT KPIR. HOWEVER A LOW PRESSURE SYSTEM MOVING NORTHEAST WILL SPREAD SHOWERS AND LOWER /MVFR/ CIGS INTO KPIR BY AROUND MID-DAY...LASTING WELL INTO TONIGHT BEFORE RELATIVELY LIGHT WINDS SWITCH AROUND TO THE NORTHWEST AND INCREASE TO 20 TO 30 KNOTS. VFR CONDITIONS ARE EXPECTED TO HOLD THROUGH LATE THIS AFTERNOON/EARLY THIS EVENING AT KABR/KMBG/KATY BEFORE THE SHOWERS AND LOWER /MVFR/ CIGS MOVE IN. LIKE KPIR...KMBG SHOULD SEE SIMILAR TIMING ON THE CHANGE IN WIND DIRECTION AND SPEED. HOWEVER...KABR AND KATY PROBABLY WON`T SEE THE ABRUPT SHIFT AND INCREASE IN WIND SPEEDS UNTIL LATER TONIGHT AT OR AFTER 06Z. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...CONNELLY SHORT TERM...SD LONG TERM...DORN AVIATION...DORN
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
855 AM EDT SAT APR 18 2015 .DISCUSSION...DENSE FOG IS SLOWING LIFTING ACROSS THE AREA THIS MORNING...HOWEVER...WILL EXTEND ADVISORY UNTIL 14Z (10 AM ET). MODELS...INCLUDING LATEST HRRR MODEL...SHOWS UPSLOPE FLOW INTO THE SPINE OF SOUTHERN APPALACHIANS THIS AFTERNOON. MARGINAL INSTABILITY WILL ALLOW SHOWERS AND ISOLATED THUNDERSTORMS TO DEVELOP ACROSS THE MOUNTAINS...THEN SPREADING INTO THE VALLEY. BEST COVERAGE...DUE TO BETTER INSTABILITY...WILL BE ACROSS THE CENTRAL AND SOUTHERN MOUNTAINS AND SOUTHWEST NORTH CAROLINA. HAVE INCREASE CHANCES FOR CONVECTION AREA-WIDE. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 76 62 76 61 / 40 100 90 60 KNOXVILLE MCGHEE TYSON AIRPORT, TN 78 61 76 61 / 40 100 90 60 OAK RIDGE, TN 77 62 75 60 / 30 100 90 60 TRI CITIES AIRPORT, TN 80 58 75 56 / 30 70 90 60 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR CHEROKEE- CLAY. TN...DENSE FOG ADVISORY UNTIL 10 AM EDT /9 AM CDT/ THIS MORNING FOR ANDERSON-BLEDSOE-BLOUNT SMOKY MOUNTAINS-BRADLEY-CAMPBELL- CLAIBORNE-COCKE SMOKY MOUNTAINS-EAST POLK-GRAINGER-HAMBLEN- HAMILTON-HANCOCK-HAWKINS-JEFFERSON-JOHNSON-KNOX-LOUDON- MARION-MCMINN-MEIGS-MORGAN-NW BLOUNT-NORTH SEVIER-NORTHWEST CARTER-NORTHWEST COCKE-NORTHWEST GREENE-NORTHWEST MONROE- RHEA-ROANE-SCOTT TN-SEQUATCHIE-SEVIER SMOKY MOUNTAINS- SOUTHEAST CARTER-SOUTHEAST GREENE-SOUTHEAST MONROE-SULLIVAN- UNICOI-UNION-WASHINGTON TN-WEST POLK. VA...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR LEE-RUSSELL- SCOTT-WASHINGTON-WISE. && $$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
941 AM CDT SAT APR 18 2015 .UPDATE... MORNING UPPER AIR DATA AND SHORT-TERM MODEL GUIDANCE HAS IDENTIFIED A SHORTWAVE TROUGH THAT IS PIVOTING AROUND THE UPPER LOW OVER COLORADO. THIS SHORTWAVE WILL TRACK THROUGH TEXAS THIS AFTERNOON AND EVENING. A DRY LINE IS FORECAST TO SET UP JUST WEST OF THE CWA BORDER THIS AFTERNOON AND WILL BECOME THE FOCUS FOR SCATTERED CONVECTION WHEN FORCING FROM THE SHORTWAVE TROUGH ARRIVES. CONVECTIVE INITIATION SHOULD START AFTER 3 PM JUST WEST OF THE CWA...WITH THESE STORMS MOVING/DEVELOPING GRADUALLY NORTHEASTWARD INTO AND THROUGH THE CWA DURING THE LATE AFTERNOON AND EVENING HOURS. GIVEN THE EXPECTED TIMING...HAVE LOWERED THE POPS ALONG AND EAST OF I-35 FOR THE TODAY PERIOD AS ANY RAIN/STORMS SHOULD HOLD OFF UNTIL THIS EVENING FOR THESE AREAS. THERE IS A LACK OF LOW LEVEL WIND FLOW EVIDENT IN THE MORNING DATA AND THE AIRMASS HAS BEEN FAIRLY WORKED OVER BY THE CONVECTION FROM YESTERDAY AND LAST NIGHT. HOWEVER THE APPROACH OF THE SHORTWAVE TROUGH WILL HELP TURN WINDS TO THE SOUTH BY THE AFTERNOON...THEREBY INCREASING MOISTURE/THETA-E ADVECTION AND BULK SHEAR VALUES ACROSS NORTH TEXAS. TEMPERATURES WILL ALSO WARM INTO THE UPPER 70S AND LOWER 80S OVER NORTH TEXAS TODAY...WHICH WILL YIELD GENERALLY 1000-2000 J/KG OF SURFACE BASED CAPE. THUS THE AIRMASS SHOULD BE RECHARGED JUST ENOUGH TO SUPPORT SCATTERED CONVECTION WITH A POTENTIAL FOR SEVERE WIND AND HAIL...ESPECIALLY WEST OF I-35 IN THE LATE AFTERNOON HOURS. THE SEVERE THREAT WILL DIMINISH AS THE STORMS HEAD EAST OF I-35 DUE TO THE LOSS OF HEATING AND INCREASING CINH. TR.92 && .AVIATION... /ISSUED 707 AM CDT SAT APR 18 2015/ /12Z TAFS/ PREVIOUS RAINFALL AND LIGHT WINDS HAVE MADE THE TAFS QUITE CHALLENGING THROUGH THE FIRST 3-6 HRS OF THE FORECAST. TO ADD TO THE MIX...SUBSIDENCE AND SOME PARTIAL BREAKS IN THE MULTIPLE LAYERS OF CLOUDS ARE CAUSING VSBYSO FLUCTUATE FROM P6SM TO 1/4SM IN FOG FROM THE TAF SITES AND AREAS TO THE WEST. WILL CARRY PREVAILING MVFR VSBYS W/TEMPO IFR-VLIFR VSBYS IN SHALLOW GROUND FOG THROUGH LATE MORNING. AS WARMING TEMPERATURES AND STRONGER SE WINDS ARRIVE BY MIDDAY...LOOK FOR VFR CIGS TO PREVAIL. AN UPPER LOW OVER COLORADO WILL DRIFT OVER THE HIGH PLAINS OF WESTERN KS BY TONIGHT. ANOTHER STORM CLUSTER WILL FORM OFF THE WEST TX DRYLINE LATE THIS AFTERNOON AND MIGRATE EWD TOWARD I-35 AND THE TAF SITES IN THE 23Z-04Z TIME FRAME ONCE AGAIN. HAVE BROUGHT STORMS IN AN HOUR SOONER AT AFW/FTW...BUT OTHERWISE WILL CARRY A 2-HR TEMPO GROUP FOR THE HIGHEST CONFIDENCE TIMING FOR TSRA WITH MVFR CIGS/CB. WITH THE UPPER LOW FURTHER EAST COMPARED TO THE SAME TIME LAST NIGHT...WE DO NOT EXPECT THE CONVECTIVE COMPLEX TO HANG AROUND QUITE AS LONG THROUGH 06Z LIKE FRIDAY EVENING. WE EXPECT LIGHT N/NE TO VRB SURFACE WINDS UNDER 5 KTS THROUGH MID-LATE MORNING. THE ENVIRONMENTAL FLOW SHOULD TAKES OVER WITH S/SE WINDS NEAR 10 KTS DURING AFTERNOON...BECOMING SOUTHERLY 5-10 KTS OVERNIGHT. IT/S HIGHLY POSSIBLE THAT THIS FLOW WILL BE DISTURBED BY CONVECTIVE OUTFLOW ONCE AGAIN WITH DIFFERING DIRECTIONS AND SPEEDS...BUT THAT WILL NEED TO BE ADDRESSED ON LATER TAFS WHEN CONFIDENCE IS HIGHER. MORE MVFR/IFR CONDITIONS MAY RETURN SUNDAY MORNING...BUT SHOULD OCCUR MAINLY AFTER 12Z AND BEYOND THIS TAF CYCLE. 05/ && .PREV DISCUSSION... /ISSUED 415 AM CDT SAT APR 18 2015/ THE UPPER LOW THAT HAS BEEN PARKED OVER THE FOUR CORNERS IS BEGINNING TO DISLODGE...AND BY THIS TIME SUNDAY MORNING IT WILL BE OVER THE HIGH PLAINS NEAR THE COLORADO/KANSAS BORDER. THIS WILL STEADILY VEER THE 700MB FLOW ACROSS WEST TEXAS TODAY...HELPING TO NUDGE THE DRYLINE FARTHER EAST THAN IN RECENT DAYS. ALTHOUGH WITHIN THE FIRST 24 HOURS OF THE LATEST GUIDANCE...OPERATIONAL SOLUTIONS VARY WIDELY ON THE LATE AFTERNOON POSITION. ALTHOUGH THE NAM IS AMONG THE FARTHEST WEST...WHICH IS UNUSUAL IN THIS SCENARIO...THE CONSENSUS AMONG THE MESOSCALE GUIDANCE IS FOR THE BOUNDARY TO REACH A VERNON-SAN ANGELO LINE NEAR PEAK HEATING. OUR FORECAST WILL FAVOR THIS POSITION. BASED ON THE MID-LEVEL FLOW... THERE SHOULD BE A BULGE NEAR THE RED RIVER. THE RAP AND TTU WRF SHOW THIS CLEARLY...ADDING TO THE CONFIDENCE IN THEIR EVOLUTION OF THE BOUNDARY TODAY. THE ATMOSPHERE ACROSS NORTH TEXAS HAS BEEN WELL WORKED OVER. THIS STABILITY...COUPLED WITH SUBSIDENCE IN THE WAKE OF A DEPARTING DISTURBANCE...SHOULD PRECLUDE MUCH ADDITIONAL PRECIPITATION THIS MORNING. WEAK LOW-LEVEL FLOW WILL RESULT IN NEGLIGIBLE MOIST ADVECTION TODAY...AND DESTABILIZATION THIS AFTERNOON WILL BE PRIMARILY GOVERNED BY SURFACE HEATING. ALTHOUGH THE I-35 CORRIDOR WILL BE SLOW TO CLEAR TODAY...WESTERN NORTH TEXAS WILL SEE SUFFICIENT SUNSHINE. EXPECT THUNDERSTORMS TO DEVELOP ALONG THE DRYLINE MID TO LATE AFTERNOON. THOUGH RELATIVELY WEAK...THE STEERING FLOW ALOFT SHOULD GUIDE THE ACTIVITY EAST THROUGH NORTH TEXAS THIS EVENING. EVEN THOUGH THE SURFACE LAYER WILL BE STEADILY STABILIZING AT THAT TIME...THE COLD POOL ASSOCIATED WITH AN ORGANIZED MCS SHOULD PROLONG THE LIFESPAN OF ITS UPDRAFTS. THIS WILL MAINTAIN A HAIL THREAT WELL INTO THE EVENING. THIS IS NOT THE TYPICAL SETUP FOR A SQUALL LINE...BUT A WELL ORGANIZED COMPLEX COULD POSE A WIND THREAT AS WELL. THE SPEED SHOULD BE SUFFICIENT TO AVOID SIGNIFICANT FLOODING CONCERNS IN MOST AREAS...BUT WHERE HEAVY RAIN HAS FALLEN RECENTLY...ADDITIONAL RAINFALL COULD REAGGRAVATE FLOODING ISSUES. AS THE UPPER LOW EJECTS THROUGH THE CENTRAL PLAINS...IT WILL SURGE A COLD FRONT THROUGH THE REGION. WITH WIDESPREAD ACTIVITY THIS EVENING...LARGE-SCALE SUBSIDENCE INVADING...AND VEERING LOW-LEVEL FLOW EARLY SUNDAY...THE ATMOSPHERE SHOULD BE UNABLE TO PRODUCE ANY FRONTAL PRECIPITATION. THE EXCEPTION WOULD BE EAST TEXAS...WHERE THE MOISTURE PROFILE WILL BE MORE FAVORABLE...AND THE FRONT WILL ARRIVE DURING THE WARM AFTERNOON HOURS. ABUNDANT APRIL SUNSHINE AND A PRONOUNCED DOWNSLOPE WIND SHOULD OFFSET ANY COLD ADVECTION BEHIND THE FRONT...AND TEMPERATURES SHOULD REACH THE 80S IN MANY AREAS SUNDAY AFTERNOON. THE COOL AIR WILL ARRIVE SUNDAY NIGHT... AND RURAL AREAS IN THE NORTHERN HALF OF THE CWA WILL LIKELY DIP INTO THE 40S MONDAY AND TUESDAY MORNING. ZONAL FLOW WILL PREVAIL MUCH OF THE UPCOMING WEEK. THE NEXT WAVE EMBEDDED IN THIS WESTERLY FLOW WILL ARRIVE AROUND TUESDAY...BUT AT THAT TIME...BOUNDARY LAYER MOISTURE MAY NOT HAVE BEEN ABLE TO SUFFICIENTLY RECOVER. ADDITIONAL RIPPLES WILL FOLLOW...MAINTAINING RAIN CHANCES. HOWEVER...POPS ARE NOTHING MORE THAN CLIMATOLOGY. EXTENDED GUIDANCE IS IN REMARKABLY GOOD AGREEMENT WITH UNSEASONABLE STRONG SHORTWAVE RIDGING AS THE NEXT UPPER LOW ENTERS THE DESERT SOUTHWEST. GFS MOS TEMPS FOR THURSDAY AND FRIDAY ARE NEAR 90 DEGREES. WITH PERFECT PROG 850MB TEMPS AROUND 20C...THIS IS NOT OUT OF THE QUESTION. A BIT CONCERNED THAT CLOUD COVER MAY PUT A DAMPER ON THE SPRING FEVER...AND FOR NOW...WILL KEEP TEMPERATURES CLOSER TO CLIMATOLOGY. 25 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 79 60 80 53 73 / 20 50 10 5 5 WACO, TX 80 60 83 53 75 / 20 50 10 5 5 PARIS, TX 75 58 77 50 70 / 20 40 20 5 0 DENTON, TX 77 57 79 49 72 / 30 50 10 5 5 MCKINNEY, TX 78 58 79 51 73 / 20 50 10 5 0 DALLAS, TX 80 62 81 54 74 / 20 50 10 5 5 TERRELL, TX 78 60 80 52 74 / 20 50 10 5 5 CORSICANA, TX 79 61 82 52 75 / 20 50 20 5 5 TEMPLE, TX 79 60 84 53 74 / 20 50 10 5 5 MINERAL WELLS, TX 81 55 79 48 74 / 40 50 10 5 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
707 AM CDT SAT APR 18 2015 .AVIATION... /12Z TAFS/ PREVIOUS RAINFALL AND LIGHT WINDS HAVE MADE THE TAFS QUITE CHALLENGING THROUGH THE FIRST 3-6 HRS OF THE FORECAST. TO ADD TO THE MIX...SUBSIDENCE AND SOME PARTIAL BREAKS IN THE MULTIPLE LAYERS OF CLOUDS ARE CAUSING VSBYSO FLUCTUATE FROM P6SM TO 1/4SM IN FOG FROM THE TAF SITES AND AREAS TO THE WEST. WILL CARRY PREVAILING MVFR VSBYS W/TEMPO IFR-VLIFR VSBYS IN SHALLOW GROUND FOG THROUGH LATE MORNING. AS WARMING TEMPERATURES AND STRONGER SE WINDS ARRIVE BY MIDDAY...LOOK FOR VFR CIGS TO PREVAIL. AN UPPER LOW OVER COLORADO WILL DRIFT OVER THE HIGH PLAINS OF WESTERN KS BY TONIGHT. ANOTHER STORM CLUSTER WILL FORM OFF THE WEST TX DRYLINE LATE THIS AFTERNOON AND MIGRATE EWD TOWARD I-35 AND THE TAF SITES IN THE 23Z-04Z TIME FRAME ONCE AGAIN. HAVE BROUGHT STORMS IN AN HOUR SOONER AT AFW/FTW...BUT OTHERWISE WILL CARRY A 2-HR TEMPO GROUP FOR THE HIGHEST CONFIDENCE TIMING FOR TSRA WITH MVFR CIGS/CB. WITH THE UPPER LOW FURTHER EAST COMPARED TO THE SAME TIME LAST NIGHT...WE DO NOT EXPECT THE CONVECTIVE COMPLEX TO HANG AROUND QUITE AS LONG THROUGH 06Z LIKE FRIDAY EVENING. WE EXPECT LIGHT N/NE TO VRB SURFACE WINDS UNDER 5 KTS THROUGH MID-LATE MORNING. THE ENVIRONMENTAL FLOW SHOULD TAKES OVER WITH S/SE WINDS NEAR 10 KTS DURING AFTERNOON...BECOMING SOUTHERLY 5-10 KTS OVERNIGHT. IT/S HIGHLY POSSIBLE THAT THIS FLOW WILL BE DISTURBED BY CONVECTIVE OUTFLOW ONCE AGAIN WITH DIFFERING DIRECTIONS AND SPEEDS...BUT THAT WILL NEED TO BE ADDRESSED ON LATER TAFS WHEN CONFIDENCE IS HIGHER. MORE MVFR/IFR CONDITIONS MAY RETURN SUNDAY MORNING...BUT SHOULD OCCUR MAINLY AFTER 12Z AND BEYOND THIS TAF CYCLE. 05/ && .PREV DISCUSSION... /ISSUED 415 AM CDT SAT APR 18 2015/ THE UPPER LOW THAT HAS BEEN PARKED OVER THE FOUR CORNERS IS BEGINNING TO DISLODGE...AND BY THIS TIME SUNDAY MORNING IT WILL BE OVER THE HIGH PLAINS NEAR THE COLORADO/KANSAS BORDER. THIS WILL STEADILY VEER THE 700MB FLOW ACROSS WEST TEXAS TODAY...HELPING TO NUDGE THE DRYLINE FARTHER EAST THAN IN RECENT DAYS. ALTHOUGH WITHIN THE FIRST 24 HOURS OF THE LATEST GUIDANCE...OPERATIONAL SOLUTIONS VARY WIDELY ON THE LATE AFTERNOON POSITION. ALTHOUGH THE NAM IS AMONG THE FARTHEST WEST...WHICH IS UNUSUAL IN THIS SCENARIO...THE CONSENSUS AMONG THE MESOSCALE GUIDANCE IS FOR THE BOUNDARY TO REACH A VERNON-SAN ANGELO LINE NEAR PEAK HEATING. OUR FORECAST WILL FAVOR THIS POSITION. BASED ON THE MID-LEVEL FLOW... THERE SHOULD BE A BULGE NEAR THE RED RIVER. THE RAP AND TTU WRF SHOW THIS CLEARLY...ADDING TO THE CONFIDENCE IN THEIR EVOLUTION OF THE BOUNDARY TODAY. THE ATMOSPHERE ACROSS NORTH TEXAS HAS BEEN WELL WORKED OVER. THIS STABILITY...COUPLED WITH SUBSIDENCE IN THE WAKE OF A DEPARTING DISTURBANCE...SHOULD PRECLUDE MUCH ADDITIONAL PRECIPITATION THIS MORNING. WEAK LOW-LEVEL FLOW WILL RESULT IN NEGLIGIBLE MOIST ADVECTION TODAY...AND DESTABILIZATION THIS AFTERNOON WILL BE PRIMARILY GOVERNED BY SURFACE HEATING. ALTHOUGH THE I-35 CORRIDOR WILL BE SLOW TO CLEAR TODAY...WESTERN NORTH TEXAS WILL SEE SUFFICIENT SUNSHINE. EXPECT THUNDERSTORMS TO DEVELOP ALONG THE DRYLINE MID TO LATE AFTERNOON. THOUGH RELATIVELY WEAK...THE STEERING FLOW ALOFT SHOULD GUIDE THE ACTIVITY EAST THROUGH NORTH TEXAS THIS EVENING. EVEN THOUGH THE SURFACE LAYER WILL BE STEADILY STABILIZING AT THAT TIME...THE COLD POOL ASSOCIATED WITH AN ORGANIZED MCS SHOULD PROLONG THE LIFESPAN OF ITS UPDRAFTS. THIS WILL MAINTAIN A HAIL THREAT WELL INTO THE EVENING. THIS IS NOT THE TYPICAL SETUP FOR A SQUALL LINE...BUT A WELL ORGANIZED COMPLEX COULD POSE A WIND THREAT AS WELL. THE SPEED SHOULD BE SUFFICIENT TO AVOID SIGNIFICANT FLOODING CONCERNS IN MOST AREAS...BUT WHERE HEAVY RAIN HAS FALLEN RECENTLY...ADDITIONAL RAINFALL COULD REAGGRAVATE FLOODING ISSUES. AS THE UPPER LOW EJECTS THROUGH THE CENTRAL PLAINS...IT WILL SURGE A COLD FRONT THROUGH THE REGION. WITH WIDESPREAD ACTIVITY THIS EVENING...LARGE-SCALE SUBSIDENCE INVADING...AND VEERING LOW-LEVEL FLOW EARLY SUNDAY...THE ATMOSPHERE SHOULD BE UNABLE TO PRODUCE ANY FRONTAL PRECIPITATION. THE EXCEPTION WOULD BE EAST TEXAS...WHERE THE MOISTURE PROFILE WILL BE MORE FAVORABLE...AND THE FRONT WILL ARRIVE DURING THE WARM AFTERNOON HOURS. ABUNDANT APRIL SUNSHINE AND A PRONOUNCED DOWNSLOPE WIND SHOULD OFFSET ANY COLD ADVECTION BEHIND THE FRONT...AND TEMPERATURES SHOULD REACH THE 80S IN MANY AREAS SUNDAY AFTERNOON. THE COOL AIR WILL ARRIVE SUNDAY NIGHT... AND RURAL AREAS IN THE NORTHERN HALF OF THE CWA WILL LIKELY DIP INTO THE 40S MONDAY AND TUESDAY MORNING. ZONAL FLOW WILL PREVAIL MUCH OF THE UPCOMING WEEK. THE NEXT WAVE EMBEDDED IN THIS WESTERLY FLOW WILL ARRIVE AROUND TUESDAY...BUT AT THAT TIME...BOUNDARY LAYER MOISTURE MAY NOT HAVE BEEN ABLE TO SUFFICIENTLY RECOVER. ADDITIONAL RIPPLES WILL FOLLOW...MAINTAINING RAIN CHANCES. HOWEVER...POPS ARE NOTHING MORE THAN CLIMATOLOGY. EXTENDED GUIDANCE IS IN REMARKABLY GOOD AGREEMENT WITH UNSEASONABLE STRONG SHORTWAVE RIDGING AS THE NEXT UPPER LOW ENTERS THE DESERT SOUTHWEST. GFS MOS TEMPS FOR THURSDAY AND FRIDAY ARE NEAR 90 DEGREES. WITH PERFECT PROG 850MB TEMPS AROUND 20C...THIS IS NOT OUT OF THE QUESTION. A BIT CONCERNED THAT CLOUD COVER MAY PUT A DAMPER ON THE SPRING FEVER...AND FOR NOW...WILL KEEP TEMPERATURES CLOSER TO CLIMATOLOGY. 25 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 79 60 80 53 73 / 40 50 10 5 5 WACO, TX 80 60 83 53 75 / 40 50 10 5 5 PARIS, TX 75 58 77 50 70 / 50 40 20 5 0 DENTON, TX 77 57 79 49 72 / 40 50 10 5 5 MCKINNEY, TX 78 58 79 51 73 / 40 50 10 5 0 DALLAS, TX 80 62 81 54 74 / 40 50 10 5 5 TERRELL, TX 78 60 80 52 74 / 40 50 10 5 5 CORSICANA, TX 79 61 82 52 75 / 40 50 20 5 5 TEMPLE, TX 79 60 84 53 74 / 40 50 10 5 5 MINERAL WELLS, TX 81 55 79 48 74 / 40 50 10 5 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/25
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
631 AM CDT Sat Apr 18 2015 .AVIATION... /12Z TAFS/ Two upper level disturbance will bring a round of storms to most TAF sites this morning and again this afternoon. Latest radar data is showing an area of storms moving east and northeast towards KSOA and KJCT and could reach those sites between 12Z and 15Z. Main impacts will be gusty winds, brief heavy rain, lightning and low visibilities. The IFR Cigs should gradually improve to VFR shortly after 15Z. The next round of storms may form along the dryline after 18Z at KSOA, KBBD and KJCT. A few of these may become severe and produce large hail, damaging winds and very heavy rainfall. && .PREV DISCUSSION... /ISSUED 420 AM CDT Sat Apr 18 2015/ SHORT TERM... (Today and Tonight) There is a threat for severe thunderstorms across the eastern half of West Central Texas today as an upper level trough associated with the upper low near the Four Corners moves across the region. The main threats will be large hail and damaging winds. SPC has placed much of the area east of the dryline in a slight risk for severe thunderstorms today. Latest radar is showing showers developing across the mountains in northern Mexico, south of Sanderson, in association with the next approaching shortwave as can be seen on water vapor satellite imagery. This could bring a round of showers and thunderstorms to West Central Texas this morning before the main upper trough moves across later this afternoon. The dryline is forecast to move east today as the RUC model progs this front from Haskell to just east of San Angelo to Sonora by early evening. This dryline should trigger scattered thunderstorms this afternoon as the following ingredients come together: dewpoints ranging from the upper 50s to the lower 60s, moderate 0-6km shear, MU CAPE Values 1500-2000 J/KG, a weak capping inversion, approaching upper trough and a right rear entrance region of the southern stream upper level jet flowing across the area. These parameters should set the stage for the development of a few supercells today, resulting in large hail and damaging winds. These storms may continue into the early evening hours before dissipating. Highest Pops were placed across the Northwest Hill Country extending north to Brownwood. Went closer to the warmer MAV MOS for temps as the dry warm air invades the western part of the region today. 26 LONG TERM... (Sunday through Friday) Cold front will move through Sunday. Dry southwest to west winds ahead of the front will not only preclude rain chances, but also give a boost to temperatures, being downslope compression. Still, cold advection will bring cooler temperatures Sunday, with highs in the 70s. Isolated dryline thunderstorms possible mid and late week. West Central Texas will be under a broad upper ridge, so widespread showers or thunderstorms not expected. Could see a few highs approach 90s, especially Wednesday and Thursday. && .PRELIMINARY POINT TEMPS/POPS... Abilene 82 55 79 49 72 / 30 20 5 5 5 San Angelo 84 54 82 50 75 / 30 10 5 5 5 Junction 82 56 85 52 75 / 50 30 5 5 5 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 26/99/99
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
611 AM CDT SAT APR 18 2015 .AVIATION... CEILINGS ARE IFR/MVFR AROUND THE AREA AIRPORTS THIS MORNING AND CONDITIONS SHOULD SLOWLY IMPROVE TO VFR BY EARLY AFTERNOON. CONVECTION HAS DEVELOPED WEST OF KDRT AND WILL SHOW VCTS FOR THE FIRST FEW HOURS OF THE VALID TAF PERIOD. CONFIDENCE REGARDING CONVECTION CHANCES THIS AFTERNOON IS NOT VERY HIGH. THE MOST LIKELY SCENARIO IS FOR THIS ELEVATED CONVECTION TO MOVE EAST THIS MORNING AND THE ATMOSPHERE TO REENERGIZE BY THE LATE AFTERNOON HOURS. THERE SHOULD BE A SURFACE CONVERGENCE ZONE DEVELOPING WEST OF THE I-35 TAF SITES. THE MOST LIKELY TIME THESE WOULD BE TO THE TERMINALS WOULD BE AROUND 22-03Z. WILL HANDLE THIS WITH A VCTS FOR NOW. ADDITIONAL MVFR RESTRICTIONS ARE POSSIBLE TONIGHT...BUT IFR IS NOT ANTICIPATED AS SLIGHTLY DRIER AIR MOVES INTO THE AREA. HAMPSHIRE && .PREV DISCUSSION... /ISSUED 401 AM CDT SAT APR 18 2015/ SHORT TERM (TODAY THROUGH SUNDAY)... AN UPPER LEVEL STORM SYSTEM IS CENTERED ACROSS COLORADO EARLY THIS MORNING. THIS SYSTEM IS FORECAST TO MOVE TO THE NORTHEAST AND THEN EAST THROUGH THE WEEKEND AND BECOMES AN OPEN WAVE LATE SUNDAY AFTERNOON. SEVERAL SHORT WAVES ASSOCIATED WITH THE UPPER LEVEL LOW ARE ANTICIPATED TO PUSH ACROSS THE AREA FOR THE NEXT 12 TO 18 HOURS AND ENHANCE STORM DEVELOPMENT LATE THIS MORNING THROUGH THE EVENING HOURS. AT LOWER LEVELS...A PRE-FRONTAL TROUGH/DRY-LINE WILL SERVE AS THE MAIN FOCUS AS STORMS FORM IN THE MOIST AND WARM SECTOR. BY THIS AFTERNOON...DEWPOINT TEMPERATURES ARE FORECAST TO REACH THE MID TO UPPER 60S WITH AREA SOUNDINGS SUGGESTING ML CAPES OF 1500 TO 2500J/KG AND LI RANGING FROM -5 TO -10 FOR LARGE TO EXTREME INSTABILITY. THEREFORE...ANY STORM THAT DOES DEVELOP HAS THE POTENTIAL TO BECOME STRONG OR SEVERE. PER SPC DAY 1 CONVECTIVE OUTLOOK...ALL OF SOUTH CENTRAL TEXAS WITH THE EXCEPTION OF THE NORTHWEST PORTION OF VAL VERDE COUNTY...IS UNDER A SLIGHT RISK OF SEVERE THUNDERSTORMS. HIRES SOLUTIONS ARE HAVING DIFFICULTIES ON TIMING AND AREAS OF STORM DEVELOPMENT INITIALLY. THE HRRR STARTS CONVECTION ACROSS THE SOUTHERN COUNTIES AS AN MCS DEVELOPS ACROSS THE COASTAL PLAINS AND MOVE TO THE EAST. THE TEXAS TECH IS MORE AGGRESSIVE ON FORMING STORMS AHEAD OF THE DRY-LINE AS IT PUSHES TO THE EAST AND OVER THE EDWARDS PLATEAU/HILL COUNTRY AREA. THE HRRR DOES DEVELOP CONVECTION AHEAD OF THE DRY-LINE THIS AFTERNOON BUT NOWHERE NEAR TEXAS TECH MODEL. THEREFORE...THE SHORT-TERM/FIRST PERIOD CONSISTS ON A BLEND OF THE HRRR/TEXAS TECH SOLUTIONS. BY LATER THIS EVENING...MID LEVEL WESTERLY WILL TAKE OVER AS THE UPPER LEVEL LOW PUSHES TO THE EAST...MARKING THE END OF RAIN CHANCES THROUGH MONDAY. WITH A WESTERLY FLOW IN PLACE FOR SUNDAY...EXPECT A NICE WARMUP WITH HIGHS IN THE UPPER 80S AND LOWER 90S. CAN NOT RULE OUT AN ISOLATED STORM ACROSS THE FAR EASTERN COUNTIES SUNDAY AFTERNOON AS LINGERING INSTABILITY REMAINS. A BACK DOOR COLD FRONT WILL PUSH ACROSS THE AREA SUNDAY EVENING TO COOL THE OVERNIGHT TEMPS INTO THE 50S AREAWIDE. LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)... A CLEAR NIGHT IS IN STORE FOR SUNDAY NIGHT WITH NORTHERLY WINDS AND COOL TEMPERATURES FOLLOWED BY A PARTLY CLOUDY DAY ON MONDAY. SOUTHERLY FLOW RETURNS TUESDAY AS WELL AS THE RAIN CHANCES FOR SOUTH CENTRAL TEXAS. SEVERAL SHORT WAVES ARE EXPECTED TO PASS BY AND TRIGGER SHOWERS AND STORMS THROUGH FRIDAY. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 81 61 89 57 76 / 40 40 - - - AUSTIN BERGSTROM INTL AIRPORT 81 60 87 55 76 / 50 40 - - - NEW BRAUNFELS MUNI AIRPORT 81 60 87 56 76 / 50 30 0 - - BURNET MUNI AIRPORT 79 57 87 53 74 / 40 40 - - - DEL RIO INTL AIRPORT 86 59 90 59 79 / 30 10 0 - 10 GEORGETOWN MUNI AIRPORT 79 59 87 54 74 / 40 40 10 - - HONDO MUNI AIRPORT 82 59 88 57 78 / 40 20 0 - - SAN MARCOS MUNI AIRPORT 81 61 86 56 75 / 50 40 0 - - LA GRANGE - FAYETTE REGIONAL 80 63 86 57 75 / 50 40 20 10 10 SAN ANTONIO INTL AIRPORT 81 61 88 58 77 / 40 30 0 - - STINSON MUNI AIRPORT 82 61 88 59 77 / 40 20 - - - && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...29 SYNOPTIC/GRIDS...17
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
612 AM CDT SAT APR 18 2015 UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE .UPDATE... ISSUED AT 407 AM CDT SAT APR 18 2015 AFTER FURTHER COORDINATION WITH ARX AND THE DNR...WILL ISSUE A RED FLAG WARNING FOR WOOD COUNTY. THE COMBO OF HUMIDITIES FALLING NEAR 20 PCT THIS AFTERNOON...MAX TEMPS IN THE 60S...WIND SPEEDS OF 10 TO 20 MPH...AND DRY FUELS WILL LEAD TO A CRITICAL FIRE WEATHER DAY THERE. THIS RED FLAG WARNING WILL TARGET THE PINE COUNTRY OF CENTRAL WISCONSIN. ADDITIONALLY...THE COLD FRONT HAS JUST PASSED OVER GREEN BAY. WINDS HAVE SHIFTED TO THE NORTH AND ARE GUSTING TO 22 KNOTS AT THE GRB AIRPORT. SOME GUSTS UP TO 25 KNOTS OVER THE BAY ARE ALSO OCCURRING. && .SHORT TERM...TODAY...TONIGHT...AND SUNDAY ISSUED AT 330 AM CDT SAT APR 18 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A FAIRLY POTENT COLD FRONT DROPPING SOUTH OVER FAR N-C WISCONSIN AND THE CENTRAL UPPER PENINSULA. NORTH WINDS BEHIND THE FRONT COMBINED WITH IMPRESSIVE PRESSURE RISES ARE CONTRIBUTING TO WIND GUSTS OVER 30 KTS OVER LAKE SUPERIOR. AS THE FRONT MOVES ACROSS NORTHERN WISCONSIN EARLY THIS MORNING...EXPECT NORTH WINDS TO STRENGTHEN AND BECOME GUSTY FOR PERIOD. ELSEWHERE...UPPER LEVEL LOW PRESSURE CONTINUES TO SPIN OVER THE CENTRAL ROCKIES AND PRODUCE SHOWERS AND THUNDERSTORMS ACROSS THE CENTRAL GREAT PLAINS. FORECAST CONCERNS INCLUDE FIRE WEATHER PARAMETERS TODAY...AND PRECIP CHANCES ON SUNDAY. TODAY...THE DRY COLD FRONT WILL DROP SOUTH ACROSS THE REST OF NORTHERN WISCONSIN EARLY THIS MORNING AND CENTRAL WISCONSIN BY MID-MORNING. BEHIND THE FRONT...THE MODELS ARE STILL DEPICTING VERY DRY AIR TO MOVE INTO NORTH-CENTRAL TO EAST-CENTRAL WISCONSIN TODAY. THOUGH NORTHEAST WINDS OFF LAKE MICHIGAN WILL HELP MODERATE THE DRY AIR OVER EASTERN WISCONSIN...MODEST WIND SPEEDS SHOULD BE ABLE TO TAP INTO THIS VERY DRY AIR JUST ABOVE THE INVERSION...AROUND 900MB. SO WAS AGGRESSIVE IN DROPPING HUMIDITIES TODAY...WHICH SHOULD FALL INTO THE TEENS OVER N-C WISCONSIN AND TO AROUND 25 PCT OVER CENTRAL WISCONSIN. EAST WINDS WILL ALSO BE APPROACHING CRITICALLY SUSTAINED SPEEDS OVER CENTRAL WISCONSIN THIS AFTERNOON. STILL WAITING FOR A FINAL DECISION FROM THE DNR CONCERNING A RED FLAG WARNING...WHICH SHOULD HAVE BY 5 AM. OTHERWISE...WILL SEE A SUNNY AND COOLER DAY. HIGHS IN THE LOW TO MID 60S AWAY FROM LAKE MICHIGAN. TONIGHT...CLOUDS WILL BE ON THE INCREASE AS THE CENTRAL ROCKIES UPPER LOW MOVES ACROSS THE CENTRAL PLAINS...WHILE A NORTHERN STREAM WAVE DIGS OVER THE NORTHERN PLAINS. AS CLOUDS THICKEN AND LOWER...WINDS BELOW 900MB WILL REMAIN OUT OF THE SOUTHEAST AND CONTINUE TO ADVECT VERY DRY AIR OVER THE REGION. THIS DRY AIR WILL HAVE TO BE OVERCOME...AND THIS MAY NOT OCCUR UNTIL LATE IN THE NIGHT OVER THE WEST. WILL MODIFY PRECIP CHANCES SLIGHTLY TO REFLECT THIS. LOWS RANGING FROM THE MID 30S NORTH TO THE MID 40S SOUTHWEST. SUNDAY...MID-LEVEL HEIGHT FALLS WILL CONTINUE TO ADVANCE INTO THE WESTERN GREAT LAKES. ONE AREA OF LOW PRESSURE WILL MOVE INTO WESTERN WISCONSIN DURING THE AFTERNOON...WHILE A SOUTHERN STREAM LOW SWINGS NE TOWARDS THE SOUTHERN TIP OF LAKE MICHIGAN. FORCING WILL IMPROVE THROUGH THE DAY AHEAD OF THESE FEATURES...THOUGH THE LEAD BAND OF LIGHT RAIN MAY DECAY DURING THE MORNING AS A RESULT OF THE DRY LOW LEVEL FLOW. THEN A SECOND ROUND OF PRECIP MAY TRY TO MOVE INTO THE AREA WITH THE APPROACHING LOW PRESSURE SYSTEMS. TEMPS ARE DIFFICULT BECAUSE OF THE PRECIP POTENTIAL...AMPLE CLOUD COVER...AND EAST WINDS. HAVE DROPPED TEMPS SOME SINCE TEMPS DO NOT TYPICALLY RISE WELL WHEN THERE IS CLOUD COVER AND EAST WINDS. PRECIP WILL ALSO LIKELY HOLD TEMPS BACK OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. SO WENT WITH HIGHS RANGING FROM THE MID 50S NORTH TO LOW 60S SOUTH. .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY ISSUED AT 330 AM CDT SAT APR 18 2015 500MB TROUGH WILL EVOLVE INTO A CLOSED UPPER LOW OVER THE WESTERN GREAT LAKES REGION EARLY NEXT WEEK...THEN MEANDER ACROSS EASTERN CANADA AND THE GREAT LAKES REGION THROUGH THE END OF NEXT WEEK. THIS WILL LEAD TO COOL AND UNSETTLED CONDITIONS...ALONG WITH A CHANCE OF SNOW LATE AT NIGHT AND EARLY MORNING HOURS. RAINFALL TOTALS STILL PROBLEMATIC SUNDAY NIGHT AS TWO SEPARATE SYSTEMS WILL BRING RAIN TO THE AREA. NORTHERN STREAM SYSTEM WILL BRING RAIN TO THE WESTERN HALF OF THE STATE...MEANWHILE A FAIRLY POTENT LOW PRESSURE SYSTEM WILL MOVE NORTHEAST INTO THE GREAT LAKES REGION SUNDAY NIGHT. STILL A LOT OF QUESTIONS ON TRACK OF SYSTEM DUE TO CLOSING UPPER LOW NORTHWEST OF THE STATE. MODEL QPF WOULD SUGGEST THAT MUCH NEEDED RAIN WOULD FALL ACROSS THE REGION. MAIN QUESTION IS WHERE AXIS OF HEAVIER RAIN WOULD FALL. MODEL RUN TO RUN CONTINUITY HAS NOT BEEN CONSISTENT...THUS LOW CONFIDENCE IN THE RAINFALL AMOUNT FORECAST. MONDAY IS NOT MUCH CLEARER AS SOME OF THE MODELS BRING DRY SLOT ACROSS THE AREA WITH A SIGNIFICANT DOWNWARD TREND IN RAINFALL AMOUNTS. THE ECMWF/CANADIAN DO NOT SHARE THIS TREND WITH THE WRF/GFS...THUS WILL KEEP SCATTERED DEPICTION/WORDING IN THE FORECAST. AS UPPER LOW CLOSES MONDAY NIGHT THROUGH WEDNESDAY...COOL CYCLONIC FLOW AND WEAK DISTURBANCES MOVING THROUGH THE MEAN FLOW WILL BRING CHANCES OF RAIN AND SNOW SHOWERS DEPENDING ON LOCATION AND TIMING OF THE DAY. AT SOME POINT...THERE COULD BE A MINOR ACCUMULATION OF SNOW ACROSS THE NORTH. SOME MODERATION IN TEMPERATURES IS EXPECTED BY THE END OF THE WEEK AS THE UPPER LOW GRADUALLY SHIFTS EAST OF THE AREA. && .AVIATION...FOR 12Z TAF ISSUANCE ISSUED AT 610 AM CDT SAT APR 18 2015 A COLD FRONT HAS MOVED THROUGH THE REGION...SHIFTING WINDS TO THE NORTHEAST. THESE NE WINDS WILL BE GUSTY AT TIMES TODAY OVER CENTRAL AND NORTHEAST WISCONSIN. THE GUSTINESS WILL DIMINISH THIS EVENING...BUT WILL SEE THICKENING AND LOWERING CLOUDS THROUGH THE NIGHT. RAIN WILL LIKELY HOLD OFF AT THE TAF SITES UNTIL SUNDAY MORNING. && .GRB WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM CDT THIS EVENING FOR WIZ035. && $$ UPDATE.........MPC SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
551 AM MDT SAT APR 18 2015 .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 415 AM MDT SAT APR 18 2015 TODAY...SLOW MOVING CLOSED UPPER LOW PROGGED TO MOVE FROM CENTRAL COLORADO THIS MORNING TO EAST CENTRAL COLORADO BY DINNER TIME. ALL MODELS INCLUDING THE HRRR SHOW A BAND OF PRECIPITATION SWINGING WESTWARD ACROSS OUR COUNTIES THIS MORNING AND AFTERNOON WITH DECENT UPWARD VERTICAL MOTION AND QUASIGEOSTROPHIC FORCING...THUS HAVE OPTED TO EXTEND OUR WINTER WEATHER ADVISORIES AND WINTER STORM WARNINGS THROUGH MIDDAY...WHILE DROPPING CHEYENNE FROM THE ADVISORY WITH TEMPERATURES LIKELY REMAINING ABOVE FREEZING AND THUS MINIMAL IMPACTS TO TRAVEL. TONIGHT...FINALLY...THE UPPER TROUGH OPENS UP AS A NORTHERN STREAM SHORTWAVE TROUGH ALOFT MOVES EASTWARD INTO WESTERN NORTH DAKOTA...THUS PRECIPITATION CHANCES DWINDLE AS THE NIGHT PROGRESSES. SUNDAY...BREEZY TO WINDY...AND COOL WITH BRISK NORTHWEST FLOW ALOFT AND DEEP UNIDIRECTIONAL WINDS. LOOKS LIKE ENOUGH LOW AND MID LEVEL MOISTURE FOR ISOLATED TO SCATTERED SHOWERS OVER AND NEAR OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES...WITH MOSTLY DRY CONDITIONS ELSEWHERE. SUNDAY NIGHT...MOIST OROGRAPHIC NORTHWEST FLOW ALOFT CONTINUES PRODUCING SCATTERED TO NUMEROUS SNOW SHOWERS OVER AND NEAR OUR SNOWY...SIERRA MADRE AND LARAMIE RANGES...DRY ELSEWHERE. .LONG TERM...(MONDAY THROUGH FRIDAY) ISSUED AT 415 AM MDT SAT APR 18 2015 THE EXTENDED PERIOD WILL START OUT TRANQUIL AND THEN END POTENTIALLY UNSETTLED. NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE ON MON WITH A WEAK SHORTWAVE MOVING OVERHEAD DURING THE DAY. COULD BE SOME LIGHT SNOW SHOWERS OVER THE SIERRA MADRE AND SNOWY RANGES...BUT MUCH OF THE ACTIVITY WILL BE CONFINED TO NORTHERN COLORADO. WITH 700MB TEMPS AROUND -6C...IT WILL BE ANOTHER DAY OF BELOW NORMAL TEMPS. WE FINALLY GET TEMPS TO MODERATE SOME BY TUES AND ESPECIALLY INTO WED...BACK INTO THE 50S AND 60S TO THE EAST OF THE LARAMIE RANGE. A BUILDING SFC HIGH OVER THE NORTHERN PLAINS ON THURS WILL CAUSE SOUTHEAST WINDS TO DEVELOP ACROSS THE PLAINS. WEAK INSTABILITY WILL BE PRESENT ON THURS AFTN...SO INCLUDED A SLIGHT OF TSTMS. A SHORTWAVE WILL THEN LIFT NORTHEASTWARD FROM ARIZONA INTO COLORADO ON FRI. BOTH THE GFS AND ECMWF INDICATE THE BEST CHANCE OF WIDESPREAD PRECIP COULD BE FRI AFTN INTO FRI NIGHT WITH GOOD EASTERLY UPSLOPE FLOW OVER THE PLAINS. 700MB TEMPS ARE AROUND -2C...SO COULD BE DEALING WITH ANOTHER CASE WHERE SNOW IS LARGELY CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 545 AM MDT SAT APR 18 2015 THE LARGE AREA OF LIGHT SNOW IS CURRENTLY ALONG AND JUST WEST OF THE LARAMIE RANGE AND MOVING WESTWARD. EXPECT IFR CONDITIONS AND LIGHT SNOW THROUGH MUCH OF THE MORNING TO THE WEST OF THE LARAMIE RANGE. IFR CIGS ARE EXPECTED THROUGH MID MORNING AT CYS BUT PRECIPITATION HAS ENDED. MVFR CONDITIONS WILL GENERALLY PREVAIL THROUGH 18Z OVER THE NEBRASKA PANHANDLE WITH PERIODS OF LIGHT RAIN...ESPECIALLY OVER THE NORTHERN PANHANDLE. A COLD FRONT WILL PUSH ACROSS THE PLAINS BY LATE THIS EVENING (AFTER 03Z) WITH BREEZY NORTH WINDS. && .FIRE WEATHER... ISSUED AT 402 AM MDT SAT APR 18 2015 NO FIRE WEATHER ISSUES WITH RECENT WIDESPREAD PRECIPITATION...AND PROJECTED HUMIDITIES AND WINDS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...WINTER STORM WARNING UNTIL NOON MDT TODAY FOR WYZ114>117. WINTER WEATHER ADVISORY UNTIL NOON MDT TODAY FOR WYZ103-105-106- 110-112. NE...NONE. && $$ SHORT TERM...RUBIN LONG TERM...ZF AVIATION...ZF FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION...DELAYED
NWS CHEYENNE WY
426 AM MDT SAT APR 18 2015 .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 415 AM MDT SAT APR 18 2015 TODAY...SLOW MOVING CLOSED UPPER LOW PROGGED TO MOVE FROM CENTRAL COLORADO THIS MORNING TO EAST CENTRAL COLORADO BY DINNER TIME. ALL MODELS INCLUDING THE HRRR SHOW A BAND OF PRECIPITATION SWINGING WESTWARD ACROSS OUR COUNTIES THIS MORNING AND AFTERNOON WITH DECENT UPWARD VERTICAL MOTION AND QUASIGEOSTROPHIC FORCING...THUS HAVE OPTED TO EXTEND OUR WINTER WEATHER ADVISORIES AND WINTER STORM WARNINGS THROUGH MIDDAY...WHILE DROPPING CHEYENNE FROM THE ADVISORY WITH TEMPERATURES LIKELY REMAINING ABOVE FREEZING AND THUS MINIMAL IMPACTS TO TRAVEL. TONIGHT...FINALLY...THE UPPER TROUGH OPENS UP AS A NORTHERN STREAM SHORTWAVE TROUGH ALOFT MOVES EASTWARD INTO WESTERN NORTH DAKOTA...THUS PRECIPITATION CHANCES DWINDLE AS THE NIGHT PROGRESSES. SUNDAY...BREEZY TO WINDY...AND COOL WITH BRISK NORTHWEST FLOW ALOFT AND DEEP UNIDIRECTIONAL WINDS. LOOKS LIKE ENOUGH LOW AND MID LEVEL MOISTURE FOR ISOLATED TO SCATTERED SHOWERS OVER AND NEAR OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES...WITH MOSTLY DRY CONDITIONS ELSEWHERE. SUNDAY NIGHT...MOIST OROGRAPHIC NORTHWEST FLOW ALOFT CONTINUES PRODUCING SCATTERED TO NUMEROUS SNOW SHOWERS OVER AND NEAR OUR SNOWY...SIERRA MADRE AND LARAMIE RANGES...DRY ELSEWHERE. .LONG TERM...(MONDAY THROUGH FRIDAY) ISSUED AT 415 AM MDT SAT APR 18 2015 THE EXTENDED PERIOD WILL START OUT TRANQUIL AND THEN END POTENTIALLY UNSETTLED. NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE ON MON WITH A WEAK SHORTWAVE MOVING OVERHEAD DURING THE DAY. COULD BE SOME LIGHT SNOW SHOWERS OVER THE SIERRA MADRE AND SNOWY RANGES...BUT MUCH OF THE ACTIVITY WILL BE CONFINED TO NORTHERN COLORADO. WITH 700MB TEMPS AROUND -6C...IT WILL BE ANOTHER DAY OF BELOW NORMAL TEMPS. WE FINALLY GET TEMPS TO MODERATE SOME BY TUES AND ESPECIALLY INTO WED...BACK INTO THE 50S AND 60S TO THE EAST OF THE LARAMIE RANGE. A BUILDING SFC HIGH OVER THE NORTHERN PLAINS ON THURS WILL CAUSE SOUTHEAST WINDS TO DEVELOP ACROSS THE PLAINS. WEAK INSTABILITY WILL BE PRESENT ON THURS AFTN...SO INCLUDED A SLIGHT OF TSTMS. A SHORTWAVE WILL THEN LIFT NORTHEASTWARD FROM ARIZONA INTO COLORADO ON FRI. BOTH THE GFS AND ECMWF INDICATE THE BEST CHANCE OF WIDESPREAD PRECIP COULD BE FRI AFTN INTO FRI NIGHT WITH GOOD EASTERLY UPSLOPE FLOW OVER THE PLAINS. 700MB TEMPS ARE AROUND -2C...SO COULD BE DEALING WITH ANOTHER CASE WHERE SNOW IS LARGELY CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1155 PM MDT FRI APR 17 2015 WIDESPREAD IFR/LIFR CONDITIONS THROUGH THE MORNING. A LARGE AREA OF RAIN IS CURRENTLY OVER THE PANHANDLE AND WILL MOVE TO AROUND THE LARAMIE RANGE BY 12Z. WITH COLDER TEMPS ACROSS WY...EXPECT LOWER VIS IN LIGHT SNOW. PERIODS OF SNOW WILL BE LIKELY ACROSS WY THROUGH THE EARLY AFTN. && .FIRE WEATHER... ISSUED AT 402 AM MDT SAT APR 18 2015 NO FIRE WEATHER ISSUES WITH RECENT WIDESPREAD PRECIPITATION...AND PROJECTED HUMIDITIES AND WINDS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...WINTER STORM WARNING UNTIL NOON MDT TODAY FOR WYZ114>117. WINTER WEATHER ADVISORY UNTIL NOON MDT TODAY FOR WYZ103-105-106- 110-112. NE...NONE. && $$ SHORT TERM...RUBIN LONG TERM...ZF AVIATION...ZF FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
328 PM MDT SAT APR 18 2015 .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. ECWMF 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 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1137 AM MDT SAT APR 18 2015 WIDESPREAD MVFR/IFR WILL CONTINUE FOR MUCH OF THE DAY AS LOW CLOUDS AND PRECIP STREAM DOWN FROM THE NORTHWEST. KCNY AND KVEL...AND KDRO WILL SLOWLY IMPROVE THROUGH THE DAY AS THE LOW OVER THE FRONT RANGE CONTINUES TO DRIFT EASTWARD. REMAINING TAF SITES WILL SEE THE PRECIP AND CIGS THROUGH 06Z WITH CONDITIONS SLOWLY IMPROVING AFTER THAT. OCCNL LULLS ARE POSSIBLE HOWEVER. ALL HIGHER TERRAIN WILL BE OBSCURED TODAY. NO CONCERNS WITH WINDS. && .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. && $$ SHORT TERM...TGR LONG TERM...JAD AVIATION...TGR
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
322 PM MDT SAT APR 18 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 322 PM MDT SAT APR 18 2015 UPPER LEVEL LOW HAS MADE VERY LITTLE EASTWARD PROGRESS TODAY AND IS STILL LOCATED OVER SOUTHWEST WASHINGTON COUNTY...BASED ON THE RECENT MOTION OF RADAR ECHOES. AFTERNOON HEATING AND COLD TEMPERATURES ALOFT HAVE DE-STABILIZED THE AIRMASS ENOUGH FOR EMBEDDED THUNDERSTORMS TO DEVELOP OVER THE FAR NORTHEAST PLAINS. MOUNTAIN AREAS HAVE BEEN PICKING UP SCATTERED SNOW SHOWERS...BUT NOT MUCH NEW SNOW ACCUMULATION...BASED ON WEB CAMERAS AND SNOTEL DATA. THE SHOWERS AND THUNDERSTORMS THIS EVENING SHOULD TAPER IN THE EVENING...WITH THE LOSS OF DAYTIME HEATING. ADDITIONAL SHOWERS ARE EXPECTED OVERNIGHT AS THE UPPER LOW MOVES EASTWARD AND THE RETURN FLOW ON THE BACKSIDE OF THE LOW MOVES OUT OF THE MOUNTAINS AND ACROSS THE PLAINS. THE NAM AND RAP FORECASTS HAVE RAIN OCCURRING THROUGH MOST OF THE NIGHT AND THEN A DECREASE IN SHOWER ACTIVITY BY MIDDAY SUNDAY. TEMPERATURES OVERNIGHT WILL DROP TO THE MID AND UPPER 30S ON THE PLAINS WHICH MAY BE COOL ENOUGH FOR SOME SNOW TO FALL. NO SIGNIFICANT ACCUMULATIONS ARE EXPECTED THOUGH. SUNDAY WILL BE A MIX OF MORNING SHOWERS AND THEN DECREASING CLOUDS IN THE AFTERNOON. STRONG INSOLATION SHOULD ALLOW AFTERNOON TEMPERATURES TO CLIMB INTO THE LOWER 50S. MOUNTAIN AREAS COULD SEE SCATTERED SNOW SHOWERS CONTINUE AS WE REMAIN UNDER MOIST NORTHWESTERLY FLOW. SNOW ACCUMULATIONS SHOULD BE LESS THAN 3 OR 4 INCHES. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 322 PM MDT SAT APR 18 2015 A COLD NORTHWEST FLOW ON THE BACK SIDE OF EXITING LONG WAY UPPER TROUGH DRIVES A CLIPPER TYPE DISTURBANCE SOUTHWARD OUT OF WYOMING SUNDAY NIGHT AND MONDAY MORNING ACCORDING TO DETERMINISTIC MODELS. SYSTEM APPEARS TO PACK ADJACENT COLD AIR...MOISTURE AND OROGRAPHIC LIFT TO PRODUCE ANOTHER ROUND OF LIGHT SNOW ACCUMULATION IN THE HIGHER MTN RANGES. MTN PASSES AND EXPOSED NORTHWEST SLOPES COULD SEE ANYWHERE FROM 2-5 INCHES OF ADDITIONAL SNOW ACCUMULATION BY MONDAY EVENING. WETBULB TEMP IS PROGGED TO BE LOW ENOUGH FOR A RAIN/SNOW MIX ON THE NEAR BY PLAINS SUNDAY EVENING...AND POSSIBLY ALL SNOW LATE SUNDAY NIGHT INTO MONDAY MORNING. THIS SYSTEM DOES NOT LOOK LIKE A BIG PRECIP MAKER FOR THE PLAINS AND ANY SNOW THAT FALLS AT LOWER ELEVATIONS SHOULD NOT ACCUMULATE. MODELS SHOW THIS DISTURBANCE QUICKLY MOVING OUT OF THE FCST AREA DURING THE DAY MONDAY AND WITH LOW LEVEL WINDS TURNING WESTERLY... TEMPS SHOULD MANAGE TO REACH THE 50S ON THE PLAINS WITH SUNSHINE RETURNING LATE IN THE DAY. MODELS SHOW A BREAK IN THE COOL AND WET NWLY FLOW PATTERN TUESDAY INTO WEDNESDAY WHEN A DIRTY SHORTWAVE UPPER RIDGE OVER THE GREAT BASIN WORKS ITS WAY ACROSS COLORADO. GFS AND NAM INDICATE A FAIR AMOUNT OF MID AND HIGH LEVEL MOISTURE WITH THIS RIDGE...SUFFICIENT TO WARRANT A CHANCE OF RAIN/SNOW SHOWERS IN THE HIGH COUNTRY ON TUESDAY AND AGAIN BY WEDNESDAY AFTERNOON. LATE DAY SHOWERS ON WEDNESDAY COULD BE ACCOMPANIED BY SOME THUNDER DURING THE WARMEST TIME OF THE DAY. ON THE PLAINS...DRY CONDITIONS WILL PREVAIL WITH A PREVAILING W-SWLY LOW LEVEL FLOW. AS A RESULT...TEMPS REBOUND WITH AFTN READINGS 1-5 DEG F ABOVE AVERAGE ON TUES AND 5-10 DEG ABOVE AVERAGE BY WED. LATE ON WEDNESDAY UPPER RIDGE OVER COLORADO APPEARS TO FLATTEN OUT WITH MODELS SHOWING A WEAK SHORTWAVE TROUGH ZOOMING UP FROM THE DESERT SOUTHWEST AND THEN ROUNDING THE TOP OF RIDGE. SHOULD THIS HAPPEN...CAN SEE PRECIP CHANCES ON THE RISE AGAIN ACRS THE CWA WITH RAIN/SNOW IN THE HIGH COUNTRY AND RAIN SHOWERS ON THE PLAINS. THERE/S ALSO A SLIGHT CHANCE OF T-STORMS BY EVENING. THURSDAY AND BEYOND...LARGE SCALE FLOW PATTERN OVER THE WESTERN CONUS IS PROGGED TO BECOME MORE LIVELY WITH YET ANOTHER LARGE SCALE UPPER TROUGH MAKING ITSELF FELT IN THE GREAT BASIN WEDNESDAY INTO THURSDAY AND ACROSS THE NORTH CENTRAL AND NORTHEAST THURSDAY AND FRIDAY. WITH AS MUCH MOISTURE AND COOL AIR WITH THIS SYSTEM...WILL CONTINUE LOW POPS FOR ALL AREAS RIGHT THROUGH SATURDAY. && .AVIATION...(FOR THE TAFS THROUGH 00Z SUNDAY LATE AFTERNOON) ISSUED AT 322 PM MDT SAT APR 18 2015 SHOWER ACTIVITY IS EXPECTED TO CONTINUE MOVING INTO THE DENVER AREA FROM THE NORTH THROUGH EARLY THIS EVENING. ISOLATED THUNDERSTORMS WILL BE POSSIBLE ALONG WITH BRIEF HEAVY RAIN AND GUSTY WINDS. THE THREAT OF THUNDER WILL CONTINUE THROUGH ABOUT 8 PM MDT. ADDITIONAL RAIN SHOWERS ARE EXPECTED OVERNIGHT AS THE UPPER LEVEL SYSTEM EXITS THE STATE...DRAGGING AN AREA OF MOIST AIR BEHIND IT. SHOWER ACTIVITY WILL MOVE OUT OF THE NORTH THROUGH THE OVERNIGHT HOURS AND MAY MIX WITH SNOW AT TIMES. NO SIGNIFICANT ACCUMULATIONS ARE ANTICIPATED. SHOWER ACTIVITY WILL BE TAPERING OFF TOMORROWWITH IMPROVING CONDITIONS THROUGH THE AFTERNOON. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DANKERS LONG TERM...BAKER AVIATION...DANKERS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1023 AM MDT SAT APR 18 2015 .UPDATE... ISSUED AT 1023 AM MDT SAT APR 18 2015 NOT MANY CHANGES TO THE FORECAST AT THIS TIME. THE CENTER OF THE UPPER LOW HAS MOVED OVER LINCOLN COUNTY WITH A VORTICITY CENTER HELPING TO KICK OFF SHOWERS AND A FEW THUNDERSTORMS EARLIER THIS MORNING. AS THE VORTICITY CENTER CONTINUES ROTATING OVER THE PLAINS...IT WILL COMBINE WITH SOME DAYTIME HEATING TO CONTINUE PRODUCING SHOWERY ACTIVITY THAT MAY EVENTUALLY MAKE IT BACK TO THE FOOTHILLS. ANOTHER BAND OF MOISTURE IN THE DEFORMATION REGION TO THE NORTHWEST OF THE UPPER LOW WILL CONTINUE ROTATING INTO THE NORTHERN MOUNTAINS THROUGH THE AFTERNOON. ADDITIONAL ACCUMULATING SNOWFALL SHOULD CONTINUE THROUGH MUCH OF THE DAY WITH AMOUNTS UP TO A FEW INCHES POSSIBLE. LATE MORNING FORECAST UPDATE WILL CONTAIN ONLY MINOR CHANGES...CHIEFLY ADDING THE MENTION OF ISOLATED AFTERNOON THUNDERSTORMS TO THE PLAINS THROUGH THE LATE MORNING AND AFTERNOON. && .SHORT TERM...(TODAY THROUGH TONIGHT ) ISSUED AT 512 AM MDT SAT APR 18 2015 UPPER LOW NEAR WALSENBURG AT THIS TIME TRACKING SLOWLY EAST. DRY SLOT HAS CURLED AROUND ACROSS MOST OF EASTERN COLORADO WITH MOISTURE WRAPPING BACK FROM WYOMING INTO THE COLORADO MOUNTAINS. AT THIS TIME THE BACK PART OF THIS SYSTEM DOES NOT HAVE STRONG LIFT WITH IT...BUT THIS IS EXPECTED TO INCREASE DURING THE DAY AS EVERYTHING CONTINUES TO SPIN AROUND THE LOW CENTER MOVING SLOWLY EAST. A COMPLEX PATTERN...BUT THE GOOD NEWS IS THE MODELS HAVE PRETTY GOOD AGREEMENT ON THE BIG PICTURE. DETAILS OF JUST WHERE THE BANDING STRUCTURE AND CONVECTION ARE VARY CONSIDERABLY. LIKING THE HRRR PRESENTATION OF THE DEVELOPING BACK EDGE SNOW BAND ACROSS THE MOUNTAINS...ROUGHLY FROM LARAMIE TOWARD RIFLE THIS MORNING. HARD TO SAY IF THE NORTH CENTRAL MOUNTAINS WILL BE IN THE BEST OF THIS...OR IF IT WILL STAY FURTHER WEST WITH THE DRIER AIR CURLING BACK OVER THE FRONT RANGE. I DID INCREASE THE POPS FOR THE MOUNTAINS...HELD OFF ON INCREASING AMOUNTS TOO MUCH AS THE SNOW MAY TEND TOWARD LIGHT SHOWERS IN THE VALLEYS WITH A STEADY BACKGROUND OF LIGHT OROGRAPHIC SNOW. IF THAT BAND WOBBLES FURTHER EAST AN ADVISORY MAY BE NEEDED. MEANWHILE ON THE PLAINS THERE IS DRIER AIR ALOFT...BUT THE LOW LEVELS REMAIN MOIST AND THE COLD POOL ALOFT WILL BE OVER THIS AREA...AND THERE WILL BE SOME LIFT FROM THE TIP OF THE WARM ADVECTION NEAR THE LOW CENTER. CONVECTION SHOULD INCREASE THROUGH THE DAY. NOT AS MUCH OF A THUNDERSTORM RISK TODAY...CAPES LIKELY AROUND 300 J/KG AROUND DENVER AND 600 NEAR THE EASTERN BORDER. I WOULD SAY NEGLIGIBLE SEVERE THREAT EXCEPT FOR THE COLD TEMPERATURES...COULD BE SOME HAIL OUT EAST BUT IT SHOULD BE HARD TO GET LARGE HAIL. FOR TONIGHT THE BACK EDGE BAND WILL TRANSLATE ACROSS OUR AREA AS THE LOW MOVES EAST. THIS SHOULD BRING A BETTER CHANCE OF SHOWERS. NORTH WINDS ALSO INCREASING...WHICH COULD WARM/DRY AREAS NORTH OF DENVER BUT ENHANCE THE THREAT OF SNOW SOUTH OF DENVER. THE NORTH WIND SHOULD ALSO BRING A FEW DEGREES OF COOLING...LOWERING SNOW LEVELS BACK DOWN TO 5-6 THOUSAND FEET. HOWEVER AIR TEMPERATURES WILL STILL BE ABOVE FREEZING IN MOST AREAS...SO STILL EXPECTING LITTLE IMPACT FOR THE METRO AREA. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 512 AM MDT SAT APR 18 2015 THERE IS WEAK TO MODERATE NORTHWESTERLY JET LEVEL FLOW OVER THE CWA SUNDAY THROUGH MONDAY NIGHT. THERE IS WEAK DOWNWARD SYNOPTIC SCALE ENERGY FOR THE CWA SUNDAY...THEN BENIGN ENERGY SUNDAY NIGHT THROUGH MONDAY NIGHT. THERE IS NORTHERLY FLOW IN THE LOWER LEVELS ON SUNDAY...WITH WEAKER NORTHEASTERLIES SUNDAY NIGHT. BOUNDARY LAYER WINDS ARE NORTHWESTERLY ON MONDAY...THEN A HINT AT NORMAL DRAINAGE PATTERNS MONDAY NIGHT. FOR MOISTURE...THERE IS PLENTY FOR THE CWA SUNDAY AND SUNDAY NIGHT...THE NAM BEING THE DRIEST. THERE IS QUITE A BIT OF MOISTURE STILL AROUND BOTH MONDAY AND MONDAY NIGHT...THE GFS BEING THE WETTEST. THERE IS A BIT OF CAPE OVER THE FAR SOUTHWEST FORECAST AREA LATE DAY SUNDAY DAY. THERE IS A BIT MORE CAPE OVER ALL THE HIGH COUNTRY LATE DAY MONDAY...BUT STILL PRETTY MEAGER AMOUNTS. THE QPF FIELDS HAVE SOME MEASURABLE PRECIPITATION MOSTLY OVER THE WESTERN TWO-THIRDS OF THE CWA SUNDAY AFTERNOON INTO MONDAY EVENING. FOR POPS...20-50%S ARE GOOD SUNDAY INTO MONDAY...THE LOWER NUMBERS FOR THE PLAINS. FOR TEMPERATURES...SUNDAY`S HIGHS ARE A BIT COLDER THAN TODAY`S BEHIND THE COLD FRONT LATE TONIGHT...EARLY SUNDAY MORNING. MONDAY`S HIGHS ONLY WARM UP 1-2 C FROM SUNDAY`S. FOR THE LATER DAYS...TUESDAY THROUGH FRIDAY...THERE IS AN UPPER RIDGE TUESDAY THROUGH THURSDAY NOW ON THE MODELS. THE NEXT UPPER TROUGH LOOKS WEAKER THAN IT DID ON YESTERDAY`S 00Z RUNS AND IT COMES THROUGH THURSDAY NIGHT AND FRIDAY. && .AVIATION...(FOR THE TAFS THROUGH 18Z SUNDAY MORNING) ISSUED AT 1023 AM MDT SAT APR 18 2015 THE COOL...MOIST AND SLIGHTLY UNSTABLE AIRMASS WILL REMAIN OVER NORTHEAST COLORADO THROUGH THIS AFTERNOON AND EVENING. MAY NEED TO MENTION SOME THUNDERSTORMS AT THE DENVER AREA AIRPORTS THROUGH THE AFTERNOON. WARMER DEW POINTS ARE MOVING INTO DENVER FROM THE NORTHEAST SO THE THREAT OF SNOW IS GOING DOWN FOR THE REST OF THIS AFTERNOON. STILL MAY SEE A MIX OF RAIN AND SNOW LATER TONIGHT AS SHOWERS CONTINUE AND TEMPERATURES COOL DOWN. SHOWERS COULD BE LONG LIVED THROUGH THE EVENING AS THE UPPER LOW PULLS OUT OF COLORADO AND MOISTURE ON THE NORTHWEST SIDE OF THE LOW ROTATES INTO THE DENVER AREA. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...DANKERS SHORT TERM...GIMMESTAD LONG TERM...RJK AVIATION...DANKERS
AREA FORECAST DISCUSSION
NWS ALBANY NY
157 PM EDT SAT APR 18 2015 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE REGION TODAY...HOWEVER ITS ASSOCIATED MOISTURE IS RATHER LIMITED SO MAINLY ONLY AN INCREASE IN CLOUDS IS EXPECTED. IN ITS WAKE...WINDS WILL BECOME BREEZY FOR SEVERAL HOURS. HIGH PRESSURE WILL BUILD IN TONIGHT AND SUNDAY RESULTING IN FAIR AND DRY WEATHER. A SERIES OF WEATHER SYSTEMS WILL IMPACT THE REGION NEXT WEEK RESULTING IN COOL...DAMP...AND UNSETTLED CONDITIONS. A WIDESPREAD RAINFALL IS EXPECTED MONDAY AND MONDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... MORNING FOG BURNED OFF QUICKLY. A SHORT WAVE TROUGH AND ITS ASSOCIATED LOW PRESSURE SYSTEM WILL PASS JUST TO OUR NORTHEAST AND MOVE ACROSS NEW ENGLAND TODAY. MOISTURE REMAINS RATHER LIMITED WITH THIS SYSTEM. LATEST HRRR ONLY INDICATES SCATTERED CONVECTION SHOULD REMAINING MAINLY TO OUR NORTH AND EAST. THE BEST POTENTIAL FOR SOME BRIEF SHOWER WILL BE NORTH OF ALBANY AND INTO THE SOUTHERN GREENS OF VERMONT. THE MAIN ISSUE FOR THE DAY IS BREEZY WESTERLY WINDS DEVELOPING FOR THE AFTERNOON. MOMENTUM TRANSFER OF THE HIGHER MAGNITUDE WINDS SUGGEST WE TAP INTO H700 LAYER WHERE 30+KTS RESIDES...SO EXPECTING GUSTS OF 25 TO 35 MPH. AS FOR TEMPERATURES...GIVEN THE DEEP MIXING EXPECTED AND CURRENT TEMPERATURES RUNNING A COUPLE DEGREES WARMER...GUIDANCE AND DRY ADIABATIC DECENT OF THOSE PARCELS ALONG WITH FAVORED LOCATIONS FOR DOWNSLOPING WOULD YIELD TEMPERATURES AT 70F OR LOWER 70S FOR VALLEY LOCATIONS AND 50S FOR THE HIGHER TERRAIN. TONIGHT...SUBSIDENCE ALONG WITH DRIER AIR ALOFT AND SURFACE HIGH BUILDING INTO THE REGION WILL RESULT IN DIMINISHING WINDS AND ANY RESIDUAL CLOUD COVER. SO A CLEAR NIGHT EXPECTED WITH LOWS RANGING FROM THE UPPER 20S ACROSS THE DACKS TO AROUND 40F ALONG THE HUDSON RIVER FROM ALBANY AND POINT SOUTHWARD. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... GEN MODEL SUITE AGREEMENT HERE WITH SOME SPREAD TWRD THE END OF THE PERIOD...MAINLY ON QPF AMNTS. SUNDAY BEGINS WITH 500HPA RIDGE AXIS FM DELMARVA TO LK HURON...AND SFC HIGH RIDGING S FM QB. RESULT WILL BE WIDESPREAD SUBSIDENCE...LOW RH...LIGHT WINDS AND BRILLIANT SUNSHINE. SUN EVNG THE 500HPA RIDGE WILL SLIDE OFFSHORE ALONG WITH THE SFC HIGH. OVERNIGHT EVOLVING UPR GRT PLAINS 500HPA CUT OFF SHIFTS E...SHARPENING THE TROF/RIDGE AMPLITUDE AND SHORTING THE WAVELENGTH AND UVM. SFC CYCLOGEN ENSUES IN THE W OHIO VLY AND LIFTS NE INTO THE S GRTLKS MON. WMFNT TRAILS SE FM MI-VA CAPES...AND LIFTS TWRD RGN SUN NT AS SFC LOW ORGANIZES ON THE COAST. RESULT WILL BE RAPIDLY INCRG LLVL SFC WIND GRAD...INCRG LLVL JETS...AND MOISTURE INFLUX INTO RGN. SHRA WILL DEVELOP OVERNIGHT SUN AND EVOLVE INTO A WIDESPREAD RAIN INTO MON. THE 500HPA CUT OFF OVER THE GRT PLAINS MOVES LITTLE BY TUES ONLY REACHING LK SUPERIOR. WITH THE SFC LOW OVER ONTARIO...THE FRONTAL STRUCTURE HAS EVOLVED INTO AN OCCLUSION FM OTTAWA VLY TO CSTL LOW OVER S NEW ENG TUE MRNG. ONCE THE OCCLUSION CLEARS THE AREA...DRY SLOT WRAPS ACROSS REGION WITH GENERALLY IMPVG CONDS. ALTHOUGH THERE IS SOME SPREAD IN THE MODELS ON THE TIMING..ALL HAVE DONE SO BY 18UTC TUES. AS 500HPA SHORT WVS ARE IN ROTATION AROUND BASE OF CUTOFF TO OUR NW...SCT -SHRA MAY STILL OCCURRING IN STEEPENING LAPSE RATE OVER FCA. TEMPS WILL BE NR TO SLIGHTLY BLO NORMALS DURING THIS PERIOD WITH HIGHS IN THE UPPER 50S TO MID 60S SUNDAY...AND MAINLY IN THE 50S AFTERWARDS. LOWS WILL BE IN THE 30S WITH 40S TUESDAY MORNING. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... THIS PERIOD WILL BE DOMINATED BY A LARGE VERTICAL LOW PRESSURE SYSTEM CENTERED OVER ONTARIO...BUT IMPACTING MUCH OF EASTERN HALF OF CANADA AND NE USA. WHILE THE MODELS DIFFER IN TIMING AND PLACEMENT OF THE FEATURES...THE MAIN STORY WILL BE 500HPA SHORT WVS ROTATING AROUND THE LARGE CUTOFF...EACH DRAGGING A SFC FRONT/BOUNDARY THROUGH THE FCA. THESE FEATURES WILL PRODUCE VRBL CLOUDS...AND TRIGGER SCT TO AT TIMES BKN -SHRA... MAYBE SOME -SHSN AT HIR TRRN...HWVR THE ACTIVITY WILL BE DIURNALLY MODULATED AS STRONG APRIL SUN...AND STEEP LAPSE RATES WILL ENHANCE THE CONVECTIVE NATURE OF THE SYSTEM AN MAY EVEN RESULT IN SOME SMALL HAIL. AS ITS OFTEN WITH THESE EVENTS...WHEN FCA IS ON SE QUADRANT OF A MAJOR CUT OFF SYSTEM...THEY TEND TO OVER DO THE DISMAL CONDITIONS CLOUDS AND SHOWERS. FCST PERIOD WILL FEATURE BLO NORMAL TEMPS WITH HIGHS MAINLY 50S...LOWS IN THE 30S...VRBLE CLOUDS...SCT -SHRA/-SHSN. THESE WILL BE DRIVEN...DIURNALLY...WITH PASSING 500HPA SHORT WVS AND BY CDFNTS. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... A SHORT WAVE TROUGH AND ITS ASSOCIATED LOW PRESSURE SYSTEM ARE PASSING JUST TO OUR NORTHEAST AND WILL MOVE ACROSS NEW ENGLAND THIS AFTERNOON. SHOWERS ASSOCIATED WITH THE SYSTEM ARE GRAZING THE EXTREME NORTHEAST PORTION OF THE FORECAST AREA AND ARE TO THE NORTH AND EAST KGFL. SO JUST AN INCREASE IN CLOUDS IS EXPECTED FOR THE TAFS. WITH THE PASSAGE OF THE SYSTEM`S COLD FRONT WINDS WILL SHIFT TO THE WEST-NORTHWEST AND INCREASE AND BECOME GUSTY WITH GUSTS AROUND 25 KNOTS. THE WINDS WILL WEAKEN THIS EVENING AS RIDGING BUILDS IN FROM THE NORTHWEST AND ANY LINGER CLOUDS WILL DISSIPATE WITH LOSS OF HEATING. WINDS WILL BECOME LIGHT OVERNIGHT AND SHIFT TO THE NORTHEAST TO SOUTHEAST SUNDAY MORNING AS THE RIDGE BUILDS IN FARTHER. OUTLOOK... SUNDAY NIGHT: HIGH OPERATIONAL IMPACT. BREEZY. LIKELY RA. MONDAY: HIGH OPERATIONAL IMPACT. BREEZY. DEFINITE RA. MONDAY NIGHT: HIGH OPERATIONAL IMPACT. DEFINITE RA. TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. WEDNESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. && .FIRE WEATHER... RED FLAG WARNING FOR ALL OF EASTERN NEW YORK...BERKSHIRES AND NORTHWEST CONNECTICUT LATER TODAY... GUSTY WINDS AND LOW RELATIVE HUMIDITIES FOR SOUTHERN VERMONT... EXTENSIVE COORDINATION OVERNIGHT ALONG WITH FORECAST METEOROLOGICAL CONDITIONS HAVE WARRANTED THE UPGRADE TO RED FLAG WARNINGS FOR EASTERN NEW YORK...BERKSHIRES AND NORTHWEST CONNECTICUT. WE WILL HIGHLIGHT THE LOW RELATIVE HUMIDITIES...SNOW COVERAGE INTO THE HIGHER TERRAIN...AND GUSTY WINDS WITH A SPECIAL WEATHER STATEMENT /SPS/ FOR SOUTHERN VERMONT. COMPACT WAVE TO THE NORTH OF THE GREAT LAKES WILL TRACK EAST- SOUTHEAST TODAY. MOISTURE ASSOCIATED WITH THIS SYSTEM REMAINS LIMITED...HOWEVER...ISOLATED SHOWERS ARE POSSIBLE MAINLY TO THE NORTH OF ALBANY AND INTO SOUTHERN VT AND PERHAPS TOUCHING NORTHERN BERKSHIRES. THEREAFTER...DEEP MIXING WITH INCREASING WINDS AND DROPPING RELATIVE HUMIDITY VALUES YIELDS A COMBINATION OF FIRE WEATHER HAZARDS TODAY. THE MAIN IMPACT POTENTIAL WILL BE DURING THE AFTERNOON HOURS. FOR SOUTHERN VERMONT...INCREASE IN CLOUD COVER ALONG WITH MARGINAL LEVELS FOR FIRE WEATHER...SNOW COVER ACROSS THE HIGHER TERRAIN AND COORDINATION WITH OFFICIALS HAVE RESULTED IN A SPECIAL WEATHER STATEMENT /SPS/. TONIGHT...WINDS WILL SUBSIDE ALONG WITH A SLOW RECOVERY OF THE RELATIVE HUMIDITY VALUES AS A SURFACE HIGH BUILDS INTO THE REGION. THIS HIGH REMAINS IN CONTROL THROUGH SUNDAY WITH LIGHT WINDS YET DRY CONDITIONS WITH MINIMUM RELATIVE HUMIDITY VALUES RANGING BETWEEN 20- 30 PERCENT. && .HYDROLOGY... NO HYDROLOGY ISSUES EXPECTED THROUGH THE MONDAY MORNING AS CONDITIONS WILL BE MAINLY DRY EXCEPT ISOLD -SHRA N TIER MIDDAY TODAY WITH A CFP. A WIDESPREAD SOAKING RAINFALL IS LIKELY LATE SUNDAY NIGHT INTO TUESDAY W/QPF ON THE ORDER OF HALF AN INCH TO AN INCH. THE NATIONAL OPERATIONAL HYDROLOGIC REMOTE SENSING CENTER (NOHRSC) INDICATES THAT THERE IS STILL A FEW INCHES OF WATER EQUIVALENT IN THE SNOW PACK ACROSS THE SRN ADIRONDACKS AND NORTHEASTERN BERKSHIRE COUNTY. PORTIONS OF THE SOUTHERN GREEN MOUNTAINS STILL HAVE 4 TO 9 INCHES OF SNOW WATER EQUIVALENT. THE GENERAL CONSENSUS IS FOR AROUND AN ONE INCH OF RAINFALL AT THIS TIME WITH THE HIGHER TOTALS SOUTH OF THE CAPITAL DISTRICT. THIS RAINFALL COMBINED WITH RISES FROM ONGOING SNOWMELT NORTH...MAY RESULT IN WITHIN BANK RISES MONDAY AND TUESDAY. 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...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR CTZ001-013. NY...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR NYZ032-033- 038>043-047>054-058>061-063>066-082>084. MA...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR MAZ001-025. VT...NONE. && $$ SYNOPSIS...IAA/SNYDER NEAR TERM...IAA/BGM/NAS/WASULA SHORT TERM...SNYDER LONG TERM...SNYDER AVIATION...IAA FIRE WEATHER...IRL/WASULA HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
251 PM EDT SAT APR 18 2015 .NEAR TERM...THROUGH TONIGHT... BUILDING UPPER RIDGE OVER FORECAST AREA THROUGH TONIGHT. SCATTERED SHOWERS AND ISOLATED T-STORMS POSSIBLE ALONG EXISTING BOUNDARIES...MAINLY ALONG WARM FRONT MOVING NORTHWARD OVER SRN GA AND FL SEA BREEZES. HRRR SUGGESTS THIS WITH PEAK COVERAGE TOWARD 00Z WITH DECREASE IN COVERAGE THEREAFTER. VISIBLE SATELLITE IMAGERY SHOWS DECENT LOW-LEVEL SW FLOW LIKELY TO PIN EAST COAST SEA BREEZE TO COAST...THUS HRRR PRIMARILY FOCUSING ANY DEVELOPMENT ON EASTWARD MOVING WEST-COAST SEA BREEZE. WITH LITTLE DYNAMIC SUPPORT...WILL KEEP POP VALUES BELOW 50 THROUGH TONIGHT. SHORT TERM...SUNDAY THROUGH MONDAY NIGHT... UPPER RIDGING MOVES OFFSHORE WHILE STRONG UPPER TROUGH OVER THE PLAINS SHIFTS SLOWLY EASTWARD. SURFACE LOW PRESSURE TRACKS FROM MS NORTHEAST TO IN DURING DAY SUNDAY...WITH OUR FORECAST IN WARM SECTOR. GREATER LOW-LEVEL SW FLOW WILL PIN EAST COAST SEA BREEZE TO COAST WHILE ADVANCING WEST COAST SEA BREEZE EASTWARD. THIS COMBINED WITH ACTIVITY COMING FROM NORTHEAST GULF OF MEXICO SUPPORTS HIGH POPS...PERHAPS HIGHEST WRN/NRN AREAS...GENERALLY 50-70 PCT. ACTIVITY DIMINISHES SUNDAY NIGHT AS MID-LEVEL DRY SLOT SPREADS OVER FORECAST AREA. FOR MONDAY...SYSTEM CONTINUES TRACKING NORTH AND EAST...COLD FRONT APPROACHES THE AREA FROM THE NORTHWEST. MODEL GUIDANCE INDICATES DRIER CONDITIONS ALOFT AND BETTER DYNAMICS PASSING WELL NORTH OF OUR FORECAST AREA...THUS CONSIDERABLY LESS PRECIP COVERAGE MON COMPARED TO SUN. WILL MAINTAIN 30 POP MON. DESPITE LESSER COVERAGE...MODEL GUIDNCE SUGGESTS A FEW STRONG OR SEVERE STORMS WILL BE POSSIBLE IN AN ENVIRONMENT WITH 2000 J/KG CAPE AND 150-200 0-3KM SR-HELICITY. SPC HAS A MARGINAL/SLIGHT RISK AREA OVER MOST OF OUR AREA MON. WARM SUN AND MON WITH HIGHS 80 TO 85 NORTH OF I-10 CORRIDOR...MID 80S I-10 SOUTHWARD. FRONT AND ASSOCIATED PRECIP SHIFT OFFSHORE MON NIGHT. FRONT WASHES OUT OVER THE SOUTHERN PART OF FORECAST AREA WHILE WEAK HIGH PRESSURE APPROACHES FROM THE GULF COAST STATES. LONG TERM...TUESDAY THROUGH SATURDAY... DRIER CONDITIONS WITH HIGH PRESSURE BUILDING NORTH OF THE AREA TUE. SLIGHTLY COOLER HIGH TEMPS IN UPPER 70S TO LOWER 80S. WILL CONTINUE TO CONFINE LOW POPS TO OUR SOUTHERN COUNTIES. LITTLE CHANGE WED-FRI...WITH ISOLATED SEA BREEZE SHOWERS POSSIBLE FL PENINSULA. BETTER CHANCE OF RAIN MAY COME NEXT SAT...BASED ON GFS AND ECM...AND WILL SHOW POPS INCREASING THEN. HIGH TEMPS GRADUALLY INCREASING TO MID 80S BY END OF WEEK. && .AVIATION...GENERALLY VFR CONDITIONS EXPECTED NEXT 24 HRS...EXCEPT LOCALLY LOWERER IN ISOLATED TSRA AND AREAS WHERE LATE NIGHT PATCHY FOG OCCURS. && .MARINE...SOUTH TO SOUTHWEST WINDS 10-15KTS AND 2-4FT SEAS EXPECTED THRU MONDAY AHEAD OF NEXT COLD FRONT. AFTER FRONT PASSES...WINDS WILL BECOME NORTH AND THEN NORTHEAST WITH HIGH PRESSURE BUILDING JUST NORTH OF THE AREA. THE HIGH IS EXPECTED TO BE WEAK...RESULTING IN FAIRLY WEAK WINDS AND LOW SEAS TUE/WED. BEFORE THE FRONT PASSES MON NIGHT...WINDS COULD APPROACH SMALL CRAFT ADVISORY LEVELS ACROSS THE OFFSHORE COMPONENT. .RIP CURRENTS...MODERATE RISK THROUGH SUNDAY DUE TO A LINGERING SWELL. && .PRELIMINARY POINT TEMPS/POPS... AMG 67 82 67 83 / 40 80 20 30 SSI 68 80 69 82 / 30 60 40 30 JAX 69 85 69 85 / 30 60 30 30 SGJ 69 82 69 83 / 30 50 30 30 GNV 68 85 68 85 / 20 60 20 30 OCF 68 85 69 85 / 20 50 20 40 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...NONE. && $$ WOLF/SANDRIK/GUILLET
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1249 PM CDT Sat Apr 18 2015 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 342 AM CDT SAT APR 18 2015 Showers and thunderstorms developing this hour across northeast Oklahoma into south central and north central Kansas, with cell movement toward the north northwest and the cluster moving more northerly. This area is forecast to move across the forecast area through the morning hours today. Struggle with the forecast continues to be timing and coverage of precipitation chances. After initial energy lifts across Eastern Kansas through early afternoon, next uncertainty will be for chances later in the afternoon. HRRR develops a cluster of showers in south central KS, but would anticipate a break between the systems with subsidence behind the main wave inhibiting convective development. Have higher chances in the morning, with lower chances middle afternoon, followed by an increase from west to east through the evening into the overnight hours as the main wave finally starts to get an easterly push, from both a northern US shortwave and an upper jet traversing the southern states. With a lull in precipitation and possibly some better sunshine out west, this would boost instability and chances for severe thunderstorms as late day storms develop along the dryline to our west and along the northward advancing warm front. Primary threat would be hail, but closer proximity to these surface features in north central Kansas could bring an isolated tornado risk there. General precipitation chances continue in the overnight hours ahead of the upper low as it continues to slowly move east. Highs for Saturday in the middle 70s west to near 70 east, with lows in the 50s. .LONG TERM...(Sunday through Friday) Issued at 342 AM CDT SAT APR 18 2015 By Sunday morning the mid/upper low will be centered over SC KS and NC OK as it progresses eastward. During this time the low will become more of an open wave as another shortwave digs into the northern plains and upper Midwest. These waves will bring a cold front through the region during the day Sunday. In the morning the better chance for showers and some thunder should be in southern KS where the front and mid level low are more coupled in the vertical. By 18Z the models are hinting at an increase of instability on the order of about 1000 j/kg ahead of the front that should stretch across eastern KS. Lapse rates are not overly impressive, and deep layer shear could reach 30 kts. Although the better shear will be further southeast over southern MO where the flow aloft is slightly stronger. Therefore kept a mention of thunderstorms for east central KS during the afternoon. A majority of the precip should clear the area around 03Z in the evening. A sharp pressure gradient behind the front will support northwest surface winds around 15 to 25 mph with gusts as up to 35 mph especially in NC KS. Cold air advection on the backside of the wave drops temps into the lower 40s and upper 30s by Monday morning. Winds do not completely decouple Sunday night so there is little concern for frost. On Monday winds remain gusty with high temps generally around 60 and partly sunny skies. Monday night will not be the classic set up for frost with a expansive high building southward, but the winds do decrease and temps are forecast to reach the mid to upper 30s. Therefore could not rule out the possibility for frost perhaps in preferred sheltered locations. NW flow aloft develops over the region as the northern stream wave deepens over the Great Lakes. The models are beginning to advertise embedded shortwaves within the NW flow, which track over the plains around mid week. This will bring small chances for either showers or thunderstorms. Late in the week a southern wave crashes the southern CA coast and tracks northeastward towards the center of the country. There are some differences on how far north the instability reaches ahead of the system, and there are additional waves in the NW flow that could interfere with the southern stream system. Confidence in any solution is low at this point. && .AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon) Issued at 1249 PM CDT SAT APR 18 2015 VFR conditions are expected outside of convective activity. MVFR to areas of IFR are expected near MHK through 20Z then an improvement to VFR by 21Z. SHRA will continue through 21Z at TOP and FOE with MHK having a low probability of shra through 00Z. High resolution short range models develop tsra in western and central KS then move it northeast toward MHK by 06Z, then affecting TOP and FOE after 09Z. WInds shift to the northwest in the 14Z-16Z period. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...67 LONG TERM...Sanders AVIATION...53
AREA FORECAST DISCUSSION
NWS WICHITA KS
1242 PM CDT SAT APR 18 2015 ...UPDATED FOR 18Z AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 350 AM CDT SAT APR 18 2015 THE UPPER LOW HAS SHIFTED EASTWARD AND IS SPINNING OVER COLORADO. SMALL PIECES OF ENERGY WITH IT HAVE HELPED TO SPARK OFF SHOWERS AND THUNDERSTORMS OVER THE PLAINS STATES DURING THE OVERNIGHT HOURS. EXPECT CENTRAL AND EASTERN KANSAS TO SEE SHOWERS AND THUNDERSTORMS THROUGH MUCH OF THE MORNING. BILLINGS WRIGHT && .UPDATE... ISSUED AT 1037 AM CDT SAT APR 18 2015 MAIN UPPER LEVEL LOW OVER THE CO ROCKIES IS BEGINNING TO MAKE SLOW PROGRESS INTO THE PLAINS THIS MORNING. DIFFLUENT SW FLOW AHEAD OF THIS UPPER LOW HAS LED TO ANOTHER ROUND OF SHOWERS AND EMBEDDED STORMS OVER THE ERN HALF OF KS. EXPECT THE SHOWERS IN ERN KS TO GRADUALLY SHIFT TO THE E-NE OF THE AREA LATE THIS MORNING. BUT ATTENTION QUICKLY SHIFTS BACK TO THE WEST...AS THIS UPPER LOW BEGINS TO PUSH EAST INTO WRN KS. ALREADY SEEING SOME CLEARING ACROSS THE WESTERN HALF OF THE FORECAST AREA...WHICH WILL LEAD TO INCREASED SURFACE HEATING INTO THE AFTERNOON HOURS. SETUP IS A LITTLE DIFFERENT THAN YESTERDAY...AS DRYLINE IN SW KS IS ON THE MOVE TO THE EAST THIS MORNING...CURRENTLY JUST TO THE WEST OF THE KDDC. LATEST LOOK AT THE HI-RES SHORT TERM MODELS SUGGEST THAT THE INCREASED HEATING BETWEEN THE DRYLINE AND WRN SECTIONS OF THE FORECAST AREA WILL HELP DESTABILIZE THE ATMOSPHERE JUST TO THE WEST OF THE FORECAST AREA THIS AFTERNOON. THIS AREA IS ALSO WEAKLY CAPPED. SO BETTER HEATING THIS MORNING...AND NOT ALOT OF RECOVERY TIME NEEDED...MAY LEAD TO CONVECTION DEVELOPING EARLIER THAN YESTERDAY. ESPECIALLY JUST AHEAD OF THE DRYLINE AS IT PUSHES EAST OF KDDC...AND PUSHES TO JUST WEST OF KPPT. SO MAY SEE CONVECTION DEVELOP AND MOVE INTO WRN SECTIONS OF THE FORECAST AREA (WEST OF I- 135) BETWEEN 20-22Z. LATEST HRRR AND ARW SUGGEST THIS SCENARIO. AS FAR AS SEVERE WEATHER CHANCES...BULK SHEAR AROUND 40 KTS AND SBCAPE VALUES EXPECTED TO BE IN THE 2000-2500 J/KG SUGGEST A STRONG TO SEVERE CHANCE WITH A MIXED MODE WITH MULTICELL CLUSTERS AND A FEW LOW TOPPED SUPERCELLS WITH LARGE HAIL (QUARTER TO GOLFBALL) AND DAMAGING WINDS THE MAIN CONCERN. CANNOT RULE OUT A WEAK/BRIEF TORNADO OR TWO...GIVEN THE DIRECTIONAL SHEAR AND INCREASED VERTICAL STRETCHING DUE TO THE STEEP LAPSE RATES. KETCHAM && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 350 AM CDT SAT APR 18 2015 MORNING: EXPECT THE SHOWERS AND THUNDERSTORMS CURRENTLY ONGOING TO CONTINUE TO DEVELOP AND SHIFT EAST-NORTHEASTWARD DURING THE MORNING HOURS. DO NOT EXPECT THESE TO BE STRONG OR SEVERE...JUST A WELCOME DRINK OF RAIN. THIS AFTERNOON/EVENING: THINK THAT THERE MAY BE SOME CLEARING ACROSS WESTERN AREAS THIS MORNING/EARLY AFTERNOON BEFORE THUNDERSTORMS FIRE AGAIN THIS AFTERNOON ALONG AND AHEAD OF THE DRYLINE. STILL SLIGHTLY CONCERNED THAT STORMS COULD FIRE EARLIER IN THE AFTERNOON...CLOSER TO 18Z WITH THE SUPPORT FROM THE UPPER DYNAMICS OF THE UPPER LOW...HOWEVER...THE BEST SUPPORT FOR COVERAGE IS CLOSER TO 21Z TO 00Z. EXPECT THESE STORMS TO IMPACT CENTRAL AND SOUTH CENTRAL KANSAS WHERE INSTABILITY AND SHEAR PARAMETERS ARE PLENTIFUL TO SUPPORT SUPERCELLS CAPABLE OF LARGE HAIL AND DAMAGING WIND. THERE IS STILL A SMALL CHANCE FOR A TORNADO...BEST CHANCES RESIDE IN SOUTH CENTRAL KANSAS AND CLOSER TO THE OKLAHOMA BORDER WITH THE BETTER HELICITY/EHI FURTHER SOUTH IN OKLAHOMA. EXPECT STORMS TO MOVE EASTWARD DURING THE EVENING. THE SEVERE CHANCES DECREASE OVER SOUTHEAST KANSAS THOUGH AS THE PARAMETERS ARE LESS FAVORABLE THERE TO SUPPORT SEVERE STORMS. DURING THE OVERNIGHT HOURS SATURDAY INTO SUNDAY: THE UPPER LOW WILL CONTINUE TO PUSH EASTWARD AND LOBES OF VORTICITY ARE EXPECTED TO CIRCLE AROUND IT WHICH COULD SPARK MULTIPLE ROUNDS OF SHOWERS/THUNDERSTORMS OVER SOUTHERN KANSAS. THE UPPER LOW WILL TRAVERSE THE STATE SUNDAY...THUNDERSTORMS WILL BECOME SHOWERS AND THE FOCUS WILL SHIFT TO EAST AND SOUTHEAST KANSAS. A COLD FRONT ASSOCIATED WITH THE UPPER LOW WILL MOVE ACROSS THE STATE AND SHIFT WINDS TO THE NORTHWEST AND GUSTY. TEMPERATURES WILL BE COOLER ON MONDAY...IN THE 60S BUT THINGS SHOULD BE DRY AS THE UPPER LOW SLOWLY BEGINS TO SHIFT NORTHEASTWARD. BILLINGS WRIGHT .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 350 AM CDT SAT APR 18 2015 THE MAIN UPPER LOW IS SLOW TO EXIT AND A PIECE OF ENERGY ROTATING AROUND ITS BACK SIDE IT WILL IMPACT THE AREA WHILE THE CENTRAL PLAINS SITS UNDER NORTHWESTERLY UPPER LEVEL FLOW. PRECIPITATION CHANCES WILL BE POSSIBLE EARLY TUESDAY AND THROUGHOUT THE DAY...BUT THE GUIDANCE HAS DISCREPANCIES AMONGST THE LOCATION OF THE PRECIPITATION...THINK IT COULD BE SOUTH OF THE STATE LINE...HOWEVER THE GFS PUSHES IT RIGHT OVER CENTRAL KANSAS. CONFIDENCE ON THIS PERIOD AND PRECIPITATION CHANCES IS LOW. BY WEDNESDAY THROUGH FRIDAY THE UPPER LOW MOVES OFF TO THE NORTHEAST AND ANOTHER SYSTEM MOVES IN FROM THE SOUTHWEST. PRECIPITATION AND POSSIBLY THUNDERSTORM CHANCES INCREASE BY WEDNESDAY THROUGH FRIDAY ACROSS THE AREA. THIS PERIOD HAS QUITE A FEW DISCREPANCIES WITH THE VARIOUS SOLUTIONS...CONFIDENCE ON ANY SOLUTION IS LOW. TEMPERATURES WILL STAY IN THE UPPER 60S AND LOW 70S...NEAR SEASONAL NORMALS. BILLINGS WRIGHT && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1240 PM CDT SAT APR 18 2015 A RATHER DIFFICULT AVIATION FORECAST...AS AN UPPER LEVEL SYSTEM CURRENTLY OVER ERN CO WILL LEAD TO LOTS OF LOW LEVEL MOISTURE ACROSS MOST OF THE FORECAST AREA. AS LIFT FROM THIS LOW INCREASES...EXPECT SHRA/TSRA TO DEVELOP IN THIS UNSTABLE ATMOSPHERE ACROSS MOST OF THE FORECAST AREA AFTER 22Z/SAT. SO PLAN ON GOING WITH VCTS FOR MOST LOCATIONS FOR THIS CHANCE. ALSO WILL GO WITH A TEMPO GROUP FOR MVFR VSBYS IN AND AROUND THE STRONGER STORMS NEAR THE KICT/KHUT AND KRSL TAF SITES. EXPECT THE THUNDER CHANCES TO CONTINUE WELL INTO THE EVENING HOURS...ESPECIALLY FOR AREAS NEAR THE KICT/KHUT/KSLN AND KRSL TAF SITES. KCNU WILL SEE A LATER ARRIVAL FOR THE VCTS....TO AROUND 06Z. THE DEEPER LOW LEVEL MOISTURE COULD LEAD TO SOME MVFR CIGS AS WELL. EXPECT A GRADUAL WIND SHIFT TO THE WEST FOR THE KRSL TAF BY SUN MORNING. KETCHAM && .FIRE WEATHER... ISSUED AT 350 AM CDT SAT APR 18 2015 FIRE WEATHER CONCERNS REMAIN LOW WITH THE UPPER LEVEL SYSTEM IMPACTING THE AREA CAUSING MULTIPLE ROUNDS OF PRECIPITATION. THE GRASSLAND FIRE DANGER INDEX REMAINS BELOW ELEVATED CONCERN LEVELS. BILLINGS WRIGHT && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 75 54 66 39 / 50 60 70 10 HUTCHINSON 75 52 62 39 / 50 60 70 10 NEWTON 73 52 62 40 / 50 60 80 10 ELDORADO 74 54 69 41 / 40 60 80 10 WINFIELD-KWLD 74 54 70 40 / 40 60 70 10 RUSSELL 75 51 59 36 / 50 60 60 10 GREAT BEND 74 50 59 35 / 50 60 60 10 SALINA 76 52 61 38 / 50 60 70 10 MCPHERSON 74 52 60 38 / 50 60 70 10 COFFEYVILLE 73 56 70 43 / 80 60 80 20 CHANUTE 72 56 70 42 / 80 60 80 20 IOLA 71 56 69 42 / 80 60 80 20 PARSONS-KPPF 73 56 69 42 / 80 60 80 20 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
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 / 40 20 30 10 LCH 64 82 63 79 / 30 10 20 10 LFT 65 84 64 79 / 50 20 20 10 BPT 64 82 63 79 / 30 20 20 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...NONE. && $$ PUBLIC/MARINE...24
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
308 PM CDT SAT APR 18 2015 .AVIATION... TERMINALS WILL CONTINUE TO PREVAIL WITH MVFR AND IFR FLIGHT CATEGORIES WITH WIDELY SCATTERED SHOWERS. THERE HAVE BEEN VERY FEW THUNDERSTORMS SO THOSE WILL BE OMITTED FROM THE FORECAST AND ADDED AS THEY INCREASE IN AREAL COVERAGE AND LOOK TO AFFECT FORECAST SITES WILL AMEND AS NEEDED. A SURFACE LOW OVER LOWER PARTS OF EAST TEXAS WILL LIFT TO THE NORTHEAST MOVING A WARM FRONT NORTHEAST OVER THE EASTERN SECTIONS OF THE FOUR STATE REGION. WINDS WILL BE VARIABLE WITH SOUTHEAST TO SOUTHWEST OVER THE SOUTHEAST SIDE OF THE LOW PRESSURE AREA AND NORTHEAST TO NORTHERLY AROUND THE BACK SIDE AS IT LIFTS NORTHEAST. A SERIES OF UPPER LEVEL DISTURBANCES ROUNDING THE LARGE AND BROAD BASE OF AN UPPER TROUGH OF LOW PRESSURE TO OUR WEST WILL CONTINUE TO PROVIDE PERIODS OF SHOWERS DURING THE NIGHT AND ON SUNDAY AS THEY ASSIST THE SURFACE LOW AND ITS MOVEMENT. THUNDERSTORMS WILL BE ON THE INCREASE DURING THE AFTERNOON SUNDAY AND INTO THE EVENING. /06/ && .PREV DISCUSSION... /ISSUED 1118 AM CDT SAT APR 18 2015/ DISCUSSION... MOST OF THE MODELS ARE NOT HANDLING THE ONGOING PRECIP VERY WELL DEPICTING WAY TOO MUCH COVERAGE COMPARED TO WHAT IS ACTUALLY OCCURRING. LACK OF PRECIP BACK TO THE SW ALSO LENDS LOW CONFIDENCETO THE MODELS. HRRR SEEMS TO BE PERFORMING SLIGHTLY BETTER SO HAVE TRIMMED POPS SLIGHTLY BASED ON THE MORE SCATTERED COVERAGE EXPECTED BY THE HRRR ACROSS MAINLY THE NERN HALF OF THE CWA THROUGH THE REMAINDER OF TODAY. STARTING TO SEE A FEW BREAKS IN THE CLOUDS WHICH WILL HELP TEMPS TO WARM QUICKLY. INSTABILITY WILL BE SUFFICIENT TO SUPPORT AT LEAST AN ISOLATED SEVERE THREAT IN PLACE. OTHERWISE...ONLY A FEW MINOR CHANGES WERE MADE TO DEWPOINT AND WIND GRIDS BASED ON LATEST OBS. UPDATED PRODUCTS HAVE BEEN SENT. /09/ PREV DISCUSSION... /ISSUED 652 AM CDT SAT APR 18 2015/ PREV DISCUSSION... /ISSUED 538 AM CDT SAT APR 18 2015/ DISCUSSION... MOSTLY CLOUDY WITH MID TO UPPER 60S AND VARIABLE WINDS OVER THE FOUR STATE AREA. THE KSHV 88D RADAR IS SHOWING MOST COVERAGE OF SHOWER AND ISOLATED THUNDERSTORMS OVER OUR OKLAHOMA AND TEXAS COUNTIES WITH DEPARTING COVERAGE FOR NOW OVER NORTH CENTRAL LOUISIANA AND SOME OF THE TEXAS SOUTHERN FLANK PULLING ACROSS TOLEDO BEND. OVERNIGHT...WE WERE CUT OFF FROM DECENT GULF MOISTURE BY A LARGE THUNDERSTORM COMPLEX MOVING EAST ALONG I-10. LOOKING AT THE WATER VAPOR...THE THICK BELT OF PACIFIC MOISTURE IS STILL BACK ACROSS SOUTH TEXAS...AND LIFTING THIS WAY. MEANWHILE...THE UPPER LOW IS SLOWLY EDGING OFF THE FOUR CORNERS INTO CO/NB/KN NOW THANKS TO ANOTHER DEEPENING TROUGH ON THE NW COAST. THE COLD FRONT WILL NOT ARRIVE UNTIL LATE AFTERNOON SUNDAY AND INTO THE EVENING. SO TODAY LOOKS MORE FAVORABLE FOR WIDE SPREAD COVERAGE WITH ONLY A MARGINAL RISK FOR SEVERE AND THEN ON SUNDAY WE ARE SLIGHT/ENHANCED FOR SEVERE WITH THE COLD FRONT BY MORE LIMITED WIDE SPREAD COVERAGE. OUR DEW POINTS WILL BE LOW TO MID 60S WITH SOME MORE HEATING AHEAD OF THE FRONT ARRIVING WITH SOME LIFT WHILE STILL UNDER THE UPPER DIVERGENT TROUGH TO OUR WEST. SPC IS LOOKING FOR ANOTHER MCS BY LATE SUNDAY AFTERNOON AND MOVING EAST QUICKLY INTO THE EVENING WHILE THE MODELS ARE ALL OVER THE PLACE WITH QPF. LITTLE CHANGE WITH A COOL DOWN BACK TO NORMAL FOR THE NEW WORK WEEK AND THEN ANOTHER FRONT MID TO LATE WEEK. /24/ && .PRELIMINARY POINT TEMPS/POPS... SHV 62 83 56 74 / 50 20 20 10 MLU 63 81 58 75 / 60 40 30 10 DEQ 58 79 50 72 / 40 30 10 10 TXK 59 80 53 72 / 40 30 20 10 ELD 60 81 54 73 / 50 40 30 10 TYR 61 82 53 73 / 40 20 10 0 GGG 61 82 54 73 / 40 20 10 0 LFK 64 85 57 76 / 50 20 20 0 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 06
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
220 PM CDT SAT APR 18 2015 .AVIATION... CLOUDS AND RAINS TO CONTINUE INTO THE EVENING HOURS. CEILINGS TO VARY FROM MVFR TO IFR ALSO VSBY EXPECTED TO REMAIN ABOVE 3 SM. && .PREV DISCUSSION... /ISSUED 1159 AM CDT SAT APR 18 2015/ UPDATE... OVERNIGHT CONVECTIVE COMPLEX HAS MOVED EAST OF THE REGION...ALLOWING THE AIRMASS TO STABILIZE BRIEFLY. ADDITIONAL CONVECTION IS BEGINNING TO DEVELOP ACRS SRN TX IN ASSOCIATION WITH THE NEXT IMPULSE IN THE MOIST SWLY FLOW. EXPECT SCT TO NMRS SHRA/TSRA TO DEVELOP DURING THE AFTN AS THIS IMPULSE TRAVELS OVER THE AREA. ADJUSTED POPS TODAY TO REFLECT RECENT HRRR AND RAP RUNS. ALSO ADJUSTED QPF AMOUNTS...AND THIS PRODUCED MUCH LOWER QPF ACRS SE TX. THUS...CANCELLED THE FFA ACRS OUR SE TX ZONES. KEPT FFA UP ACRS LA AND ALTHOUGH THE RISK OF WIDESPREAD HEAVY RAIN AND FLOODING IS LOWER...THERE IS STILL THE POSSIBILITY FOR SOME LOCALIZED HEAVY RAIN ACRS PORTIONS OF SW LA. REMAINDER OF FCST IS RELATIVELY UNCHANGED WITH JUST SOME MINOR EDITS TO HOURLY TEMPS...DEWPOINTS AND WINDS. 24 PREV DISCUSSION... /ISSUED 656 AM CDT SAT APR 18 2015/ AVIATION...AEX STARTING OUT IFR ON CIGS THIS MORNING. ELSEWHERE VFR CIGS WITH LGT RAIN. THERE COULD BE A FEW EMBEDDED TSTMS LATER THIS MORNING. MVFR LATE TNITE AS WE SCATTER OUT ALOFT BUT REMAIN MOIST IN THE BOUNDARY LAYER. COULD SEE SOME IFR CIGS IN SCUD ALONG WITH SOME LIGHT FOG. SWEENEY PREV DISCUSSION... /ISSUED 501 AM CDT SAT APR 18 2015/ DISCUSSION... HEAVY RAINS OVERNIGHT SO FAR HAVE BEEN CONFINED MAINLY TO SOUTHERN JEFFERSON COUNTY IN SOUTHEAST TEXAS WITH 3-4 INCHES OF RAIN MAINLY SOUTH OF URBAN AREAS...TO 2 TO 3 INCHES IN NORTHWEST CAMERON PARISH OVER THE MARSHES. OTHERWISE...1 TO 2 INCH RAINS WERE COMMON FROM OPELOUSAS...WEST TO DEQUINCY...TO ORANGE AND VILLAGE MILLS. THE NORTHERN AREAS HAVE BEEN SPARED THIS TIME AROUND. THE BIG QUESTION TODAY IS THE AMOUNT OF AVAILABLE MOISTURE AND INSTABILITY NEEDED TO CONTINUE THE FLASH FLOOD WATCH AND OF COURSE THE RISK OF SEVERE STORM DEVELOPMENT. THE ATMOSPHERE HAS BEEN WORKED OVER PRETTY WELL...AND THE CONVECTION OVER THE COASTAL WATERS FROM 40NM TO WELL BEYOND 60NM HAS DIVERTED THE DEEP GULF MOISTURE FURTHER SOUTH WAY FROM AREA. THERE IS A GOOD PLUME OF CLOUDS BLOWING OFF GULF CONVECTION SWEEPING NORTHWARD ACROSS AREA TODAY. ON THE OTHER HAND...SOUNDING FORECAST PROFILES SHOW PRECIPITABLE WATER VALUES HOLDING ABOVE 1.5 INCHES OR BETTER AT LEAST UNTIL 00Z AND THEN DROP OFF. THEREFORE...WILL NOT MENTION SEVERE THUNDERSTORMS IN THE FORECAST AS THE RISK FROM SPC IS SLIGHT. CLOUDS MAY HINDER INSTABILITY FOR MOST OF THE DAY ANYWAY. HOWEVER...CANNOT RULE OUT AN ISOLATED BRIEF SEVERE MID TO LATE AFTERNOON SOMEWHERE...BUT THAT WOULD BE ISOLATED IF ANY. THE FLASH FLOOD WATCH COULD BE LIFTED TODAY IF IT WERE NOT FOR THE SATURATED SOILS AND FILLED DITCHES. REALLY BELIEVE THAT THE FIRST HALF OF THE MORNING THERE IS LITTLE OF ANY THREAT OF HEAVY RAINS...HOWEVER IN THE AFTERNOON...COULD SEE SOME REDEVELOPMENT OF HEAVIER RAINS FROM UPSTREAM INSTABILITY...THEREFORE...WILL LEAVE FLASH FLOOD WATCH UP FOR NOW AS IT WOULD NOT BE PRUDENT TO MOVE IT JUST YET. THE UPPER LEVEL LOW SPINNING ACROSS COLORADO THIS MORNING WITH THE SOUTHERLY TROUGH EXTENDING INTO THE SOUTH CENTRAL SOUTHERN STATES...WILL CONTINUE TO MIGRATE EASTWARD OVER THE NEXT 48 HOURS. AS IT DOES...DEEP MOISTURE AND ENERGY WILL SHIFT EASTWARD DURING THIS PERIOD. THEREFORE...DO EXPECT TO SEE A BIG DROPOFF IN RAIN CHANCES ON SUNDAY BUT KEEP LOW POPS IN AS AS FRONT SWEEPS THROUGH THE AREA LATE SUNDAY NIGHT INTO MONDAY. THE FRONT WILL RETURN AS A WARM FRONT BY MIDWEEK AND THEREFORE WILL GET A BUMP UP IN POPS AS THE WARM FRONTAL BOUNDARY MOVES NORTHWARD. RAIN CHANCES ONCE AGAIN FALL BY THE END OF THE WEEK AS THE REGION WILL REMAIN BETWEEN SYSTEMS. MARINE... AM WIDESPREAD CONVECTION WILL END FROM WEST TO EAST THIS MORNING. REDEVELOPMENT COULD BEGIN LATER THIS AFTERNOON BUT PROBABLY WILL NOT BE QUITE AS BAD AS THE LAST COUPLE OF DAYS HAVE BEEN. ONSHORE FLOW WILL CONTINUE WITH PERIODIC DISRUPTION DUE TO THUNDERSTORMS AND OUTFLOWS. 06 && .PRELIMINARY POINT TEMPS/POPS... AEX 64 82 61 78 / 50 20 20 10 LCH 65 82 64 80 / 40 20 20 10 LFT 66 84 65 80 / 60 30 20 10 BPT 65 82 64 80 / 40 20 20 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR LAZ027>033- 041>045-052>055-073-074. TX...NONE. GM...NONE. && $$ AVIATION...19
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1159 AM CDT SAT APR 18 2015 .UPDATE... OVERNIGHT CONVECTIVE COMPLEX HAS MOVED EAST OF THE REGION...ALLOWING THE AIRMASS TO STABILIZE BRIEFLY. ADDITIONAL CONVECTION IS BEGINNING TO DEVELOP ACRS SRN TX IN ASSOCIATION WITH THE NEXT IMPULSE IN THE MOIST SWLY FLOW. EXPECT SCT TO NMRS SHRA/TSRA TO DEVELOP DURING THE AFTN AS THIS IMPULSE TRAVELS OVER THE AREA. ADJUSTED POPS TODAY TO REFLECT RECENT HRRR AND RAP RUNS. ALSO ADJUSTED QPF AMOUNTS...AND THIS PRODUCED MUCH LOWER QPF ACRS SE TX. THUS...CANCELLED THE FFA ACRS OUR SE TX ZONES. KEPT FFA UP ACRS LA AND ALTHOUGH THE RISK OF WIDESPREAD HEAVY RAIN AND FLOODING IS LOWER...THERE IS STILL THE POSSIBILITY FOR SOME LOCALIZED HEAVY RAIN ACRS PORTIONS OF SW LA. REMAINDER OF FCST IS RELATIVELY UNCHANGED WITH JUST SOME MINOR EDITS TO HOURLY TEMPS...DEWPOINTS AND WINDS. 24 && .PREV DISCUSSION... /ISSUED 656 AM CDT SAT APR 18 2015/ AVIATION...AEX STARTING OUT IFR ON CIGS THIS MORNING. ELSEWHERE VFR CIGS WITH LGT RAIN. THERE COULD BE A FEW EMBEDDED TSTMS LATER THIS MORNING. MVFR LATE TNITE AS WE SCATTER OUT ALOFT BUT REMAIN MOIST IN THE BOUNDARY LAYER. COULD SEE SOME IFR CIGS IN SCUD ALONG WITH SOME LIGHT FOG. SWEENEY PREV DISCUSSION... /ISSUED 501 AM CDT SAT APR 18 2015/ DISCUSSION... HEAVY RAINS OVERNIGHT SO FAR HAVE BEEN CONFINED MAINLY TO SOUTHERN JEFFERSON COUNTY IN SOUTHEAST TEXAS WITH 3-4 INCHES OF RAIN MAINLY SOUTH OF URBAN AREAS...TO 2 TO 3 INCHES IN NORTHWEST CAMERON PARISH OVER THE MARSHES. OTHERWISE...1 TO 2 INCH RAINS WERE COMMON FROM OPELOUSAS...WEST TO DEQUINCY...TO ORANGE AND VILLAGE MILLS. THE NORTHERN AREAS HAVE BEEN SPARED THIS TIME AROUND. THE BIG QUESTION TODAY IS THE AMOUNT OF AVAILABLE MOISTURE AND INSTABILITY NEEDED TO CONTINUE THE FLASH FLOOD WATCH AND OF COURSE THE RISK OF SEVERE STORM DEVELOPMENT. THE ATMOSPHERE HAS BEEN WORKED OVER PRETTY WELL...AND THE CONVECTION OVER THE COASTAL WATERS FROM 40NM TO WELL BEYOND 60NM HAS DIVERTED THE DEEP GULF MOISTURE FURTHER SOUTH WAY FROM AREA. THERE IS A GOOD PLUME OF CLOUDS BLOWING OFF GULF CONVECTION SWEEPING NORTHWARD ACROSS AREA TODAY. ON THE OTHER HAND...SOUNDING FORECAST PROFILES SHOW PRECIPITABLE WATER VALUES HOLDING ABOVE 1.5 INCHES OR BETTER AT LEAST UNTIL 00Z AND THEN DROP OFF. THEREFORE...WILL NOT MENTION SEVERE THUNDERSTORMS IN THE FORECAST AS THE RISK FROM SPC IS SLIGHT. CLOUDS MAY HINDER INSTABILITY FOR MOST OF THE DAY ANYWAY. HOWEVER...CANNOT RULE OUT AN ISOLATED BRIEF SEVERE MID TO LATE AFTERNOON SOMEWHERE...BUT THAT WOULD BE ISOLATED IF ANY. THE FLASH FLOOD WATCH COULD BE LIFTED TODAY IF IT WERE NOT FOR THE SATURATED SOILS AND FILLED DITCHES. REALLY BELIEVE THAT THE FIRST HALF OF THE MORNING THERE IS LITTLE OF ANY THREAT OF HEAVY RAINS...HOWEVER IN THE AFTERNOON...COULD SEE SOME REDEVELOPMENT OF HEAVIER RAINS FROM UPSTREAM INSTABILITY...THEREFORE...WILL LEAVE FLASH FLOOD WATCH UP FOR NOW AS IT WOULD NOT BE PRUDENT TO MOVE IT JUST YET. THE UPPER LEVEL LOW SPINNING ACROSS COLORADO THIS MORNING WITH THE SOUTHERLY TROUGH EXTENDING INTO THE SOUTH CENTRAL SOUTHERN STATES...WILL CONTINUE TO MIGRATE EASTWARD OVER THE NEXT 48 HOURS. AS IT DOES...DEEP MOISTURE AND ENERGY WILL SHIFT EASTWARD DURING THIS PERIOD. THEREFORE...DO EXPECT TO SEE A BIG DROPOFF IN RAIN CHANCES ON SUNDAY BUT KEEP LOW POPS IN AS AS FRONT SWEEPS THROUGH THE AREA LATE SUNDAY NIGHT INTO MONDAY. THE FRONT WILL RETURN AS A WARM FRONT BY MIDWEEK AND THEREFORE WILL GET A BUMP UP IN POPS AS THE WARM FRONTAL BOUNDARY MOVES NORTHWARD. RAIN CHANCES ONCE AGAIN FALL BY THE END OF THE WEEK AS THE REGION WILL REMAIN BETWEEN SYSTEMS. MARINE... AM WIDESPREAD CONVECTION WILL END FROM WEST TO EAST THIS MORNING. REDEVELOPMENT COULD BEGIN LATER THIS AFTERNOON BUT PROBABLY WILL NOT BE QUITE AS BAD AS THE LAST COUPLE OF DAYS HAVE BEEN. ONSHORE FLOW WILL CONTINUE WITH PERIODIC DISRUPTION DUE TO THUNDERSTORMS AND OUTFLOWS. 06 && .PRELIMINARY POINT TEMPS/POPS... AEX 77 64 82 61 / 80 50 20 20 LCH 77 65 82 64 / 80 40 20 20 LFT 78 66 84 65 / 90 60 30 20 BPT 78 65 82 64 / 70 40 20 20 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR LAZ027>033- 041>045-052>055-073-074. TX...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS SHREVEPORT LA
1118 AM CDT SAT APR 18 2015 .DISCUSSION... MOST OF THE MODELS ARE NOT HANDLING THE ONGOING PRECIP VERY WELL DEPICTING WAY TOO MUCH COVERAGE COMPARED TO WHAT IS ACTUALLY OCCURRING. LACK OF PRECIP BACK TO THE SW ALSO LENDS LOW CONFIDENCETO THE MODELS. HRRR SEEMS TO BE PERFORMING SLIGHTLY BETTER SO HAVE TRIMMED POPS SLIGHTLY BASED ON THE MORE SCATTERED COVERAGE EXPECTED BY THE HRRR ACROSS MAINLY THE NERN HALF OF THE CWA THROUGH THE REMAINDER OF TODAY. STARTING TO SEE A FEW BREAKS IN THE CLOUDS WHICH WILL HELP TEMPS TO WARM QUICKLY. INSTABILITY WILL BE SUFFICIENT TO SUPPORT AT LEAST AN ISOLATED SEVERE THREAT IN PLACE. OTHERWISE...ONLY A FEW MINOR CHANGES WERE MADE TO DEWPOINT AND WIND GRIDS BASED ON LATEST OBS. UPDATED PRODUCTS HAVE BEEN SENT. /09/ && .PREV DISCUSSION... /ISSUED 652 AM CDT SAT APR 18 2015/ AVIATION... SEEING QUITE A SPREAD IN CIGS THIS MORNING...WITH IFR CIGS OVER NCNTRL LA AS WELL AS PORTIONS OF DEEP E TX...WITH A MIX OF MVFR/VFR CIGS ELSEWHERE ACROSS THE REGION. A WEAK SFC WAVE HAS DEVELOPED ALONG A STATIONARY FRONT OVER EXTREME ERN TX...AND SHOULD SHIFT ENE INTO NRN LA THIS MORNING...RESULTING IN THE DEVELOPMENT OF LOW MVFR/IFR CIGS BY MIDMORNING OVER NW LA/SW AR. SCT -SHRA AND ISOLATED -TSRA CONTINUE TO DEVELOP OVER PORTIONS OF E TX/SE OK/ADJACENT SW AR THIS MORNING...WITH THIS TREND EXPECTED TO CONTINUE/SPREAD FARTHER E ACROSS NCNTRL LA/SCNTRL AR THIS MORNING BEFORE GRADUALLY DIMINISHING FROM SW TO NE THIS AFTERNOON. HAVE TEMPOED MENTION OF SHRA INTO THE N LA/SW AR TERMINALS THIS MORNING...BUT LOW CONFIDENCE PRECLUDES MENTION FOR THE AFTERNOON. WHILE CIGS WILL BE SLOW TO IMPROVE TODAY OVER N LA/SW AR NEAR THE SFC FRONTAL WAVE...SHOULD SEE CIGS IMPROVING TO VFR BY MID- AFTERNOON ACROSS E TX...SCATTERING OUT BY 00Z SUNDAY. COULD ALSO SEE THE RETURN OF IFR/MVFR CIGS LATE IN THE TAF PERIOD ACROSS E TX/N LA JUST PRIOR TO DAYBREAK SUNDAY...WITH THESE CIGS EXPECTED TO SPREAD FARTHER NNE SHORTLY THERE AFTERWARDS. VRB WINDS 6KTS OR LESS TODAY WILL BECOME LT/VRB AFTER 00Z. /15/ PREV DISCUSSION... /ISSUED 538 AM CDT SAT APR 18 2015/ DISCUSSION... MOSTLY CLOUDY WITH MID TO UPPER 60S AND VARIABLE WINDS OVER THE FOUR STATE AREA. THE KSHV 88D RADAR IS SHOWING MOST COVERAGE OF SHOWER AND ISOLATED THUNDERSTORMS OVER OUR OKLAHOMA AND TEXAS COUNTIES WITH DEPARTING COVERAGE FOR NOW OVER NORTH CENTRAL LOUISIANA AND SOME OF THE TEXAS SOUTHERN FLANK PULLING ACROSS TOLEDO BEND. OVERNIGHT...WE WERE CUT OFF FROM DECENT GULF MOISTURE BY A LARGE THUNDERSTORM COMPLEX MOVING EAST ALONG I-10. LOOKING AT THE WATER VAPOR...THE THICK BELT OF PACIFIC MOISTURE IS STILL BACK ACROSS SOUTH TEXAS...AND LIFTING THIS WAY. MEANWHILE...THE UPPER LOW IS SLOWLY EDGING OFF THE FOUR CORNERS INTO CO/NB/KN NOW THANKS TO ANOTHER DEEPENING TROUGH ON THE NW COAST. THE COLD FRONT WILL NOT ARRIVE UNTIL LATE AFTERNOON SUNDAY AND INTO THE EVENING. SO TODAY LOOKS MORE FAVORABLE FOR WIDE SPREAD COVERAGE WITH ONLY A MARGINAL RISK FOR SEVERE AND THEN ON SUNDAY WE ARE SLIGHT/ENHANCED FOR SEVERE WITH THE COLD FRONT BY MORE LIMITED WIDE SPREAD COVERAGE. OUR DEW POINTS WILL BE LOW TO MID 60S WITH SOME MORE HEATING AHEAD OF THE FRONT ARRIVING WITH SOME LIFT WHILE STILL UNDER THE UPPER DIVERGENT TROUGH TO OUR WEST. SPC IS LOOKING FOR ANOTHER MCS BY LATE SUNDAY AFTERNOON AND MOVING EAST QUICKLY INTO THE EVENING WHILE THE MODELS ARE ALL OVER THE PLACE WITH QPF. LITTLE CHANGE WITH A COOL DOWN BACK TO NORMAL FOR THE NEW WORK WEEK AND THEN ANOTHER FRONT MID TO LATE WEEK. /24/ && .PRELIMINARY POINT TEMPS/POPS... SHV 77 62 83 56 / 50 50 20 20 MLU 76 63 81 58 / 60 60 40 30 DEQ 76 58 79 50 / 40 40 30 10 TXK 75 59 80 53 / 50 40 30 20 ELD 75 60 81 54 / 50 50 40 30 TYR 78 61 82 53 / 20 40 20 10 GGG 77 61 82 54 / 30 40 20 10 LFK 78 64 85 57 / 30 50 20 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 09
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1215 PM EDT SAT APR 18 2015 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 328 AM EDT SAT APR 18 2015 ANOTHER SUNNY DAY IS EXPECTED TODAY WITH HIGHS AROUND 70. LOW PRESSURE WILL MOVE NORTH FROM THE GULF AREA SUNDAY BRINGING QUITE A BIT OF RAIN WITH IT. AFTER THE LOW MOVES EAST...COLDER AIR WILL MOVE OVER LOWER MICHIGAN AND REMAIN IN PLACE NEXT WEEK. HIGHS WILL ONLY REACH THE MID 40S TO MID 50S NEXT WEEK. && .UPDATE... ISSUED AT 1055 AM EDT SAT APR 18 2015 I INCREASED THE HIGH TEMPERATURE AROUND 5 DEGREES FOR THIS AFTERNOON BASED ON MORNING SOUNDING DATA. THE RAP MODEL SEEMS TO BE DOING A BETTER JOB OF SHOWING CURRENT TEMPERATURES...DEW POINTS AND WINDS SO I USED THAT TO INCREASE THE WIND SPEED...TEMPERATURES AND LOWER THE DEW POINTS. THAT ALL BEING SO... WE COULD SEE HIGHS IN THE MID TO UPPER 70S OVER THE WESTERN SECTIONS OF THE CWA THIS AFTERNOON. WE WILL BE GETTING CLOSE TO RED FLAG CONDITIONS IF THIS HAPPENS. FOR NOW I WILL LET OUR HWO AND POST OF FACEBOOK COVER THIS ISSUE. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 328 AM EDT SAT APR 18 2015 FORECAST CONCERNS DEAL WITH THE LOW APPROACHING SUNDAY. AFTER ANOTHER SUNNY AND MILD DAY TODAY CLOUDS WILL INCREASE TONIGHT AS A PHASED NORTHERN/SOUTHERN STREAM LOW APPROACHES FROM THE SOUTH. STRONG 60KT LLJ WILL DRAW UP ABUNDANT MOISTURE INTO THE SYSTEM. STRONG ISENTROPIC LIFT LATE SUNDAY MORNING WILL LEAD TO RAPID RAIN DEVELOPMENT FROM SOUTH TO NORTH. LOOK FOR THE WIND TO INCREASE AS WELL...AT LEAST UNTIL THE LOW MOVES OVERHEAD SUNDAY EVENING. SHORT RANGE MODELS HAVE BEEN CONSISTENT MOVING THE LOW DIRECTLY OVER THE CWA SO CONFIDENCE IS PRETTY HIGH WE/LL SEE RAIN. QPF AROUND 3/4 INCH LOOKS POSSIBLE AS MIXING RATIOS CLIMB TO 8G/KG BY LATE SUNDAY AFTERNOON. THERE STILL ISN/T A STRONG SIGNAL FOR THUNDER SO WE KEPT IT OUT OF THE GRIDS. HOWEVER GIVEN A SLIGHT DECREASE IN STABILITY NOTED WE CAN/T RULE IT OUT EITHER. MONDAY WILL BE MUCH COOLER AS THE LOW MOVES EAST AND WEST WINDS DEVELOP. HIGHS IN THE MID 50S ARE EXPECTED. THE UPPER LOW WILL MOVE OVER THE CWA MONDAY SO WE/LL CONTINUE TO SEE SCATTERED SHOWERS. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 328 AM EDT SAT APR 18 2015 MOST OF NEXT WEEK WILL BE COLDER THAN NORMAL WITH SCATTERED RAIN OR MIXED RAIN AND SNOW SHOWERS AS AN UPPER LOW BECOMES PARKED OVER THE NORTHERN GREAT LAKES REGION. DEEP CYCLONIC FLOW AND COLD ADVECTION WILL LEAD TO CONSIDERABLE CLOUDINESS WITH HIGHS ONLY IN THE 40S AND FREQUENTLY BREEZY CONDITIONS. THE MAIN RISK FOR SNOW SHOWERS WILL BE AT NIGHT AND DURING THE EARLY MORNING WHEN THE BOUNDARY LAYER IS COOLEST... ESPECIALLY FOR HIGHER ELEVATIONS NEAR AND NORTH OF ROUTE 10 WHERE SOME LIGHT ACCUMULATIONS EVEN APPEAR POSSIBLE. GFS/ECMWF DO NOT LOOK PARTICULARLY BULLISH WITH QPF AT ANY TIME NEXT WEEK ALTHOUGH SPOKES OF VORTICITY ROTATING AROUND THE UPPER LOW MAY LEAD TO OCCASIONAL BOUTS OF INCREASED COVERAGE OF HEAVIER SHOWERS. THINGS APPEAR TO DRY OUR THURSDAY NIGHT AND FRIDAY WHEN THE UPR LOW MOVES EAST AND SFC RIDGING ARRIVES FROM THE WEST. BY FRIDAY HIGHS COULD BE BACK UP INTO THE 50S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY) ISSUED AT 1215 PM EDT SAT APR 18 2015 VFR CONDITIONS WILL CONTINUE THROUGH 18Z SUNDAY. ENE WINDS WILL GUST TO AROUND 20 KTS AT TIMES THIS AFTERNOON AND BECOME EASTERLY AND GUST TO 20 TO 25 KTS SUNDAY MORNING AND AFTERNOON. SHOWERS WILL GRADUALLY MOVE IN FROM SOUTH TO NORTH AT ALL THE TERMINALS BETWEEN 18Z AND 21Z SUNDAY AFTERNOON WHEN CONDITIONS WILL DETERIORATE TO PRIMARILY MVFR WITH POCKETS OF IFR POSSIBLE IN HEAVIER SHOWERS. && .MARINE... ISSUED AT 328 AM EDT SAT APR 18 2015 A COLD FRONT WILL MOVE THROUGH EARLY TODAY AND TURN THE WINDS TO THE NORTHEAST. THE OFFSHORE FLOW WILL CONTINUE TONIGHT AND STRENGTHEN. A SCA MAY BE NEEDED TONIGHT. && .HYDROLOGY... ISSUED AT 1126 AM EDT SAT APR 18 2015 A GOOD SOAKING RAINFALL IS STILL ON TRACK TO AFFECT THE ENTIRE AREA BEGINNING SUNDAY. THE BULK OF THE MOISTURE WILL LIKELY FALL BETWEEN SUNDAY AFTERNOON INTO MONDAY MORNING WITH SOME GUIDANCE HINTING AT OVER AN INCH IN SPOTS. ADDITIONAL CHANCES FOR RAIN WILL SPAN THROUGH THE MIDDLE OF THE WEEK BUT ARE NOT EXPECTED TO BE QUITE AS ABUNDANT WITH MOISTURE. RIVERS WILL MAINLY RESPOND IN THE MANNER OF MINOR RISES. THIS SHOULD MOSTLY CONSIST OF WITHIN BANK RISES. I HAVE A LITTLE MORE CONFIDENCE IN THINKING MAPLE RAPIDS COULD FLIRT WITH ADVISORY CRITERIA ONCE AGAIN. THIS IS PENDING THE AMOUNT OF RAINFALL RECEIVED THROUGH EARLY MONDAY. OTHERWISE...WE ARE LOOKING PRETTY GOOD WITH THIS NOT BEING A CONVECTIVE MODE OF PRECIPITATION...NO REAL SURPRISES AT THIS POINT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...04 SHORT TERM...04 LONG TERM...MEADE AVIATION...LAURENS HYDROLOGY...JAM MARINE...04
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1200 PM CDT SAT APR 18 2015 .UPDATE... IN THE PAST HOUR OR TWO IT IS BECOMING INCREASINGLY APPARENT THAT DEEP CONVECTION STRETCHING FROM THE NORTH CENTRAL GULF TO THE WESTERN GULF IS REALLY GOING TO HAMPER VIGOROUS THUNDERSTORM DEVELOPMENT OVER THE LOWER MS VALLEY LATE TODAY INTO THIS EVENING. STILL NOT CONVINCED THAT MOISTURE...LIFT AND INSTABILITY INGREDIENTS WILL NOT BE ENOUGH AT LEAST ALONG AND SOUTHEAST OF THE NATCHEZ TRACE CORRIDOR TO GET A FEW SEVERE STORMS GOING EVENTUALLY WITH A HEAVY RAIN THREAT PERSISTING AS WELL. FOR THAT REASON WE HAVE DOWNPLAYED SEVERE POTENTIAL IN ALL AREAS THROUGH THE REST OF TODAY AND INTO TONIGHT IN ALL AREAS (ALTHOUGH KEEPING SOME RISK GOING IN THE SOUTHEAST HALF OF THE CWA). WE WILL WATCH TRENDS CLOSELY TO ADJUST WITH THE AFTERNOON UPDATE. /BB/ && .PREV DISCUSSION... /ISSUED 1025 AM CDT SAT APR 18 2015/ UPDATE... THINGS THIS MORNING ARE EVOLVING GENERALLY AS ANTICIPATED...ALTHOUGH QUESTION MARKS GOING INTO LATE TODAY STILL PERSIST IN SOME MEASURE OWING TO THUNDERSTORMS ANCHORED TO THE SE LA COAST. THESE STORMS WERE PREVIOUSLY SPREADING A LIGHT RAIN SHIELD INTO MY SOUTHERN ZONES...BUT THE NORTHWARD EXTENT OF THIS PRECIP HAS SHRUNK IN THE LAST FEW HOURS. ALSO...VIGOROUS STORMS JUST SOUTH OF THE COAST HAVE BEEN GRADUALLY LOSING COVERAGE SINCE DAYBREAK AND THEY SHOULD EBB QUICKLY INTO MIDDAY AS UPPER JET PULLING BACK TO THE WEST REMOVES MUCH OF THE UPPER LEVEL SUPPORT. HOWEVER...IF SAID EVOLUTION DOES NOT COME TO PASS WITH HASTE THEN MOISTURE TRANSPORT BLOCKING AND CLOUD COVER INTO SOME OF MY SOUTHERN ZONES WILL HINDER POTENTIAL FOR VIGOROUS INLAND THUNDERSTORM FORMATION AS WE GO INTO THIS AFTERNOON. BUT ASSUMING THE LATTER CAVEAT IS NOT AN ISSUE...LATEST HRRR AND DOWNSCALED NAM RUNS POINT TO WORRISOME STORMS MOVING INTO MY SOUTHERN ZONES (ESPECIALLY SOUTH CENTRAL AND SE MS) ZONES FROM MID AFTERNOON THROUGH MID EVENING. ATMOSPHERIC LAPSE RATES WILL MAINLY BE AT OR LESS THAN 6 C/KM IN THE H700-H500 LAYER BUT MLCAPE PEAKING OVER 1000 J/KG SHOULD BE SUFFICIENT GIVEN EXPECTED LOW LEVEL AND DEEP LAYER SHEAR TO PRODUCE ORGANIZED STORMS. ONCE AGAIN...A FEW TORNADOES CANNOT BE RULED OUT. THERE IS NOT ENOUGH EVIDENCE YET TO GO CHANGING THE PREVIOUS FORECAST AND SEVERE WEATHER EXPECTATIONS MUCH. HOWEVER...WE WILL BE WATCHING TRENDS CLOSELY OVER THE NEXT FEW HOURS AND WILL SEE IF VERY RECENT HRRR HINTS THAT SEVERE RISK WILL BE STRONGLY FOCUSING SOUTHEAST OF THE NATCHEZ TRACE APPEAR SOLID. IF THAT IS THE CASE WE WILL UPDATE ACCORDINGLY...BUT EVEN IF WE DO FOCUS THE SEVERE RISK EVEN MORE CONSIDERABLY IN SOUTHERN ZONES THE RISK OF LOCALIZED FLOODING PROBLEMS STILL LOOKS TO EXTEND ACROSS A MUCH LARGER PORTION OF THE FORECAST AREA. /BB/ AVIATION...IFR CATEGORY STRATUS PREVAILS ACROSS THE TAF SITES THIS MORNING WITH SHOWERS MOVING ACROSS HBG. EXPECT THESE CONDITIONS TO PERSIST UNTIL LATE MORNING/EARLY AFTERNOON BEFORE FINALLY MIXING OUT. SHRA WILL MOSTLY CONFINED TO LOCATIONS SOUTH OF THE HEZ-HBG CORRIDOR THIS MORNING AS A CONVECTIVE COMPLEX SLIDES EASTWARD ALONG THE COAST...BUT A NEW ROUND OF SHRA/TSRA IS EXPECTED BY MID/LATE AFTERNOON LASTING INTO THE EVENING WITH AN APPROACHING DISTURBANCE. THERE MAY BE A WINDOW OF OPPORTUNITY FOR BETTER FLYING CONDITIONS DURING THE EARLY AFTERNOON...FOLLOWED BY POOR FLYING CONDITIONS PERSISTING FROM MID/LATE AFTERNOON THROUGH THE EVENING. /EC/15/ PREV DISCUSSION... /ISSUED 454 AM CDT SAT APR 18 2015/ SHORT TERM...TODAY THROUGH TONIGHT...AN ACTIVE WEATHER WEEKEND IS IN STORE AS TWO ROUNDS OF SEVERE WEATHER ARE EXPECTED TO IMPACT THE ARKLAMISS. THE FIRST ROUND WILL BE INITIATED BY INCREASINGLY FAVORABLE CYCLONIC AND SHEARED FLOW DEVELOPING OVER THE LOWER MS VALLEY REGION LATER THIS AFTERNOON AND EVENING. THE CONVECTIVE SYSTEM CURRENTLY MOVING EAST ALONG THE THE LA COAST WILL DELAY TIMING OF THE MORE SIGNIFICANT THUNDERSTORM ACTIVITY UNTIL MID/LATE AFTERNOON...BUT VERY MOIST AND UNSTABLE AIR WITH PRECIPITABLE WATER VALUES > 1.75 INCHES AND ML CAPE NEAR 1000 J/KG SHOULD BE AVAILABLE FOR VIGOROUS CONVECTIVE DEVELOPMENT AT THAT TIME. WITH DEEP LAYER AND LOW LEVEL SHEAR ON THE INCREASE...STILL EXPECT ORGANIZED STORMS TO DEVELOP WITH THE MOST FAVORABLE SET-UP FOR SEVERE WEATHER AND HEAVY RAINFALL ALONG/SOUTH OF THE I-20 CORRIDOR...BUT WILL SAY THAT CONFIDENCE IS A LITTLE SHAKIER NOW ON THIS SCENARIO BASED ON RECENT HIGH RES GUIDANCE TRENDS. IF THE NEXT ROUND OF CONVECTIVE DOES NOT MATERIALIZE AS ANTICIPATED DUE TO THE MORNING CONVECTION...OR IF IT DEVELOPS FARTHER EAST...THEN IT IS POSSIBLE THAT MORE ROBUST CONVECTION WOULD IMPACT NORTHERN PORTIONS OF THE ARKLAMISS AND THIS COULD ALLOW THE SEVERE WEATHER/HEAVY RAINFALL THREAT TO SHIFT FARTHER NORTH AS WELL. STAY TUNED FOR UPDATES TO THIS FORECAST LATER THIS MORNING AS CONVECTIVE EVOLUTION HOPEFULLY BECOMES A LITTLE MORE CLEAR. /EC/ SUNDAY THROUGH SUNDAY NIGHT...MODELS FOR SUNDAY CONTINUE TO SUPPORT THE RISK FOR SEVERE STORMS ALONG WITH SOME POTENTIAL FOR A HIGHER END EVENT. WHAT IS STARTING TO BECOME MORE CLEAR IS MUCH OF THE DAY LOOKS TO BE IN A LULL FROM CONVECTION AFTER MORNING ACTIVITY DEPARTS TO THE EAST AND THE ROUND OF STORMS WILL BE MORE FOCUSED LATER BETWEEN A 5PM TO 3AM WINDOW. IN THE WAKE OF THE SAT SYSTEM...MUCH STEEPER LAPSE RATES WILL SPREAD OVER THE AREA (7.0 TO 7.5 C/KM)(29-31C VERTICAL TOTALS). ALOFT MUCH COLDER TEMPS WILL MOVE IN WITH H5 READINGS OF -15 TO - 16C. THIS WILL ALL SUPPORT SBCAPE OF 2000-3000 J/KG AS SFC HEATING REACHES AROUND 80 DEGREES. THIS WILL ALL SUPPORT VIGOROUS STORMS WITH ROBUST UPDRAFTS. CONCURRENT WITH THIS WILL BE AN OVERALL DRIER ATMOSPHERE COLUMN AS WELL WITH PWS AROUND 1.2 INCHES. THIS WILL LEND TO KEEPING STORMS MORE DISCRETE ALONG WITH AN EASTWARD DEEP LAYER (0-6KM) SHEAR VECTOR OF 40-50KTS. EXPECTATIONS ARE FOR NOT MANY (ISO/SCT) SUPERCELLS THAT WILL PACK QUITE THE PUNCH. LARGE HAIL > GOLF BALL SIZE APPEARS VERY POSSIBLE ALONG WITH DAMAGING WINDS WHICH ALSO COULD BE HIGHER END. DUE TO THIS POSSIBILITY OF SEEING SIGNIFICANT TYPE WEATHER (>2 IN HAIL)...WILL UP OUR OUTLOOK TO SIG OVER A DECENT PORTION OF THE NW. ELSEWHERE THE OUTLOOK WILL REMAIN SIMILAR AS STORMS MAY LOSE SOME POTENCY AS THEY PUSH FURTHER EAST AND GET LATER INTO THE OVERNIGHT. /CME/ LONG TERM...MONDAY THROUGH SATURDAY....MONDAY MORNING THE LARGE CLOSED LOW IS EXPECTED TO BE CENTERED OVER THE UPPER MISSISSIPPI VALLEY WITH ASSOCIATED LARGE AMPLITUDE UPPER LEVEL TROUGHING OVER THE EASTERN TWO THIRDS OF THE CONUS. MODELS AGREE THAT THE ASSOCIATED SURFACE LOW WILL BE OVER THE WESTERN GREAT LAKES REGION MONDAY MORNING BUT THERE ARE TIMING DIFFERENCES WITH THE TRAILING COLD FRONT THAT IS EXPECTED TO BE OVER SOUTHEAST MISSISSIPPI. CONSENSUS PLACES THIS COLD FRONT AND THE BULK OF THE PRECIPITATION JUST SOUTHEAST OF OUR CWA AT DAYBREAK BUT WL MAINTAIN LOW CHANCES OF LIGHT RAIN IN OUR NORTHEAST THROUGH MID MORNING AS A WEAK SHORTWAVE PASSES OVER OVERHEAD. DRY WEATHER IS EXPECTED AREAWIDE BY NOON. SLIGHTLY COOLER AND MUCH DRIER AIR WILL FILTER INTO OUR CWA MONDAY KNOCKING DEW POINTS INTO THE 40S DURING THE AFTERNOON. DRY WEATHER IS EXPECTED TO LAST OVER OUR CWA THROUGH TUESDAY AS A SURFACE HIGH MOVES EAST ACROSS OUR AREA. THIS SURFACE HIGH WILL SHIFT EAST WEDNESDAY AND THE RESULTING RETURN FLOW WILL INCREASE MOISTURE TO SUPPORT RAIN CHANCES AGAIN FROM THE WEST BY WEDNESDAY AFTERNOON. WARMER THAN NORMAL TEMPERATURES AND GREATER RAIN CHANCES ARE EXPECTED FOR THE END OF THE WEEK BUT THERE ARE SIGNIFICANT DIFFERENCES IN THE MODELS WITH SOME MAIN FEATURES. THE NORTHERN CLOSED LOW WILL MOVE SLOWLY EAST ACROSS THE GREAT LAKES REGION TUESDAY AND WEDNESDAY AND BE OVER THE NEW ENGLAND STATES BY FRIDAY. THIS LOW WILL TRY TO HELP SUPPORT ANOTHER COLD FRONT DROPPING INTO OUR CWA THURSDAY INTO FRIDAY BUT INDUCED SHORTWAVE RIDGING DOWNSTREAM OF A SECOND CLOSED LOW MOVING OVER THE DESERT SOUTHWEST THURSDAY LOOKS TO IMPEDE THE COLD FRONT INTO OUR AREA. SHORTWAVES ROUNDING THE BASE OF THE SOUTHERN CLOSED LOW LOOK TO COMBINE WITH INCREASING MOISTURE AND DAYTIME HEATING FOR A ROUND OF CONVECTION THURSDAY AND FRIDAY. BOTH GFS AND ECMWF OPEN THE CLOSED LOW AND BRING THE REMAINING SHORTWAVE TROUGH ACROSS OUR REGION SATURDAY BUT DIFFER ON THE SURFACE FEATURES WITH THE GFS DEPICTING A MUCH DEEPER LOW AND STRONGER COLD FRONT ACROSS OUR AREA. FOR NOW...GREATEST POPS THROUGH THE LONG TERM WILL BE CARRIED FRIDAY AND FRIDAY NIGHT. /22/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 75 64 81 61 / 84 66 31 39 MERIDIAN 76 65 82 64 / 71 83 37 34 VICKSBURG 73 64 81 59 / 86 49 34 46 HATTIESBURG 77 66 84 65 / 86 78 33 28 NATCHEZ 75 64 82 60 / 91 54 28 42 GREENVILLE 73 63 81 57 / 58 47 49 57 GREENWOOD 74 63 79 59 / 56 55 44 56 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ JAN
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1243 PM CDT Sat Apr 18 2015 .DISCUSSION... Issued at 411 AM CDT SAT APR 18 2015 Overview: Closed and cut-off upper low now over central CO will be the primary weather driver for the weekend. Feature will open up by Sunday and move east in response to a shortwave trough digging southeast through the Northern Rockies. Expect to see a several rounds of active convection Saturday and Sunday. Today - Sunday: While eyes have been fixated on the closed upper low now over CO/NM the real weather makers will be periodic vorticity lobes and associated layered frontogenesis that rotate northeast out from under the upper low. Little going on over the CWA early this morning as we`re lacking any discernible feature to initiate any convection. But we are finally seeing the long awaited next round of convection. Regional radars have recently lit up from OK northward through central KS albeit further west than we`ve been expecting. Favor following the HRRR reflectivity trends, which have slowed down the arrival of the KS/OK convection and latest NAM mass fields/h7 vorticity prog. Thus have pared back PoPs significantly for first part of morning and slowed the eastward expansion of precipitation. Even still this is a forecast which will need adjusting throughout the day as the convection tied to the upper low has had repeated false starts as well as expanding too fast to the east. Thickening cloud cover and rain-cooled air will affect temperatures over the western half of the CWA more so than the eastern half where precipitation will move in later in the day. Precipitable water values around two standard deviations above normal suggest potential for 1"+ rains through tonight. Weak shear and MUCAPEs under 1000J/kg favor convection remaining below severe limits. Should see a lull in the rain later tonight and first part of Sunday before the next wave of convection moves in. The upper low will have opened up by then and will accelerate eastward. Anticipate convection increasing as it moves east through the CWA in response to improving upper level dynamics and low-level convergence associated with a cold front. However, once again the 0-6km shear of 20-25kts and modest MUCAPEs favor convection being sub-severe. Monday - Tuesday: A fairly deep upper trough stretching from MN through the Mid MS Valley will influence our weather with widespread subsidence on the backside of the trough. Abundant solar insolation will help offset cold air advection but still result in below average temperatures. Wednesday - Friday: As the upper trough shifts east through the Great Lakes an upper ridge will build eastward through the Rockies and into the Central/Southern Plains. Medium range models are in agreement that a cold front will surge through the region on Wednesday. However, they disagree on whether or not convection will be generated. Moisture fields look minimal and believe any shower activity will be widely scattered. As we get into Thursday and Friday the ECMWF and GFS both lift a shortwave out of the southwestern U.S. but the GFS appears unrealistic in deepening a surface over the Central High Plains and spreading warm advection convection too far downstream. Will use a blended forecast but overall confidence low for Thursday`s PoPs but timing looks better for the PoPs on Friday. && .AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon) Issued at 1240 PM CDT SAT APR 18 2015 Light to moderate rain, with perhaps an isolated, brief pocket of heavy rain will move through the area through the next few hours. There could be a couple isolated rumbles of thunder, but overall the threat for lightning/thunder is minimal with this activity. There will likely be a lull in the rain through the evening and overnight hours, before another round picks up on Sunday morning. Expect some spotty activity prior to sunrise Sunday, with confidence rising in widespread moderate rain by the late morning to early afternoon hours. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ DISCUSSION...MJ AVIATION...Leighton
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
259 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 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1228 PM CDT SAT APR 18 2015 LARGE UPPER LEVEL LOW CONTINUES TO MOVE ONLY VERY SLOWLY ACROSS EASTERN COLORADO. EXPECT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO DEVELOP AS A RESULT THIS AFTERNOON AND TONIGHT. THE BEST CONCENTRATION OF SHOWERS AND STORMS WILL BE ACROSS CENTRAL AND SOUTHWEST NEBRASKA...INCLUDING THE KLBF TAF SITE. LATE TONIGHT A COLD FRONT WILL QUICKLY MOVE SOUTHEAST THROUGH THE AREA...THIS WILL BRING MVFR AND POSSIBLE IFR CEILINGS WITH IT FROM AROUND 07Z TO 16Z SUNDAY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SPRINGER SHORT TERM...TAYLOR MEDIUM RANGE...CDC EXTENDED RANGE...SPRINGER AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
106 PM CDT SAT APR 18 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 328 AM CDT SAT APR 18 2015 SPC SUGGESTED SIGNIFICANT SEVERE WEATHER POTENTIAL THIS AFTERNOON AND EARLY THIS EVENING ACROSS PARTS OF SOUTHWEST AND NCNTL NEB. A PORTION OF THE LOW PRESSURE ACROSS SWRN KS THIS MORNING IS EXPECTED TO LIFT NORTHEAST THROUGH SCNTL AND ERN NEB THIS AFTERNOON SETTING UP A UNSTABLE WARM SECTOR FROM ROUGHLY IMPERIAL TO ONEILL. ALTHOUGH THE RAP IS FAIRLY QUIET THE NAM AND HRRR SBN MODELS SUGGEST REASONABLE POTENTIAL FOR CONVECTIVE DEVELOPMENT THIS AFTN IF SKIES PARTIALLY CLEAR ALLOWING FOR TEMPERATURES TO RISE INTO THE MID AND UPPER 60S. SATELLITE SHOWS CLEARING THIS MORNING ACROSS CNTL HIGH PLAINS OF KS/COLO AND IT IS BELIEVED THIS CLEARING WILL MOVE INTO SCNTL NEB THIS AFTN. THE STORM ACTIVITY COULD BEGIN AS EARLY AS 18Z IN THE SOUTHWEST WITH THE NAM SOLN OR AS LATE AS 21Z-00Z IN THE HRRR MODEL. SATELLITE TIMING TOOLS INDICATE THE CLEARING ACROSS KS COULD REACH SOUTHWEST NEB BY 13-15Z THIS MORNING WHICH WOULD PROVIDE A GOOD START FOR MODEST HEATING GIVEN THAT THIS CLEARING AREA WOULD TEND TO FILL IN WITH DEVELOPING CUMULUS. ONE WEAKNESS ARE THE WIND FIELDS 500MB AND BELOW WHICH ARE LIGHT PRODUCING BULK SHEAR VALUES OF 30KT OR LESS WHICH MIGHT SUPPORT MORE OF HEAVY RAIN THREAT. STILL TEMPERATURES ALOFT WILL BE VERY COLD AS THE H500MB LOW ACROSS COLO MOVES EAST TO NEAR LIMON/SPRINGFIELD. WINDS AT 300MB ARE STRONG NEAR 65KT POTENTIALLY ENHANCING UPDRAFTS AND PROVIDING VENTILATION. FREEZING LEVELS ARE NEAR 5KFT SUPPORTING A LOW TOP STORM ENVIRONMENT AND GOOD POTENTIAL FOR HAIL. THE NAM IS PRODUCING AROUND 2000 J/KG OF CAPE AT NORTH PLATTE AND BROKEN BOW WHILE THE RAP AND OTHER MODELS SHOW HALF OR LESS THAT VALUE. NORTHWEST WINDS WILL SWEEP IN FROM THE WEST IN THE WAKE OF THE DISTURBANCE TONIGHT. THIS SHOULD PRODUCE DRYING AND DECREASING RAIN CHANCES FROM MIDNIGHT ONWARD. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 328 AM CDT SAT APR 18 2015 SUNDAY WILL SEE THE STRONG LOW PRESSURE WEAKENING AS IT PUSHES EAST WHILE A TROUGH DIGS ACROSS THE CANADIAN PLAINS. SOME LINGERING SUNDAY MORNING SHOWERS ARE POSSIBLE IN THE EASTERN ZONES...HOWEVER THE BIGGER EVENTS OF THE DAY WILL BE THE CAA AND INCREASING NW WINDS. AS THE LOW PUSHES ACROSS KS...DRY AIR WILL QUICKLY FILL IN BEHIND...RESULTING IN DECREASING CLOUDS FROM WEST TO EAST IN THE MORNING. BY AFTERNOON SHOULD SEE MOSTLY SUNNY SKIES FOR ALL. THE SUN WILL COMBINE WITH THE STRONG NW WINDS /GUSTING TO 30 TO 40 MPH/ TO PROMOTE GOOD MIXING OF THE BL AND OFFSET THE CAA AND TEMPS PUSH INTO THE 50S. EARLY IN THE WEEK THE TROUGH DIGS TOWARDS THE GREAT LAKES REGION AND ABSORBS THE SOUTHERN LOW. ELONGATED SFC HIGH PRESSURE BUILDS ACROSS THE HIGH PLAINS. THE ACTIVE WEATHER IS WELL TO THE NE ALTHOUGH A FEW UPPER LEVEL DISTURBANCES WILL RIDE ALONG THE NW FLOW OVERHEAD AND BRING SOME PASSING CLOUDS AT TIMES. LIMITED MOISTURE IN THE LOWER LEVELS AND MODELS/FORECAST ARE DRY. TEMPS TO START THE WEEK WILL BE CHILLY IN THE MORNING WITH MOST AREAS NEAR OR BELOW THE FREEZING MARK. STILL A COUPLE OF WEEKS FROM TYPICAL LAST FREEZE FOR MOST OF THE AREA...SO NO HEADLINES NEEDED YET. HIGHS REBOUND NICELY WITH A WARMING TREND WITH 60S MAYBE 70 FOR WED AND THURS. EYES THEN FOCUS ON A TROUGH AS IT DIGS ACROSS THE SOUTHWEST. MODELS IN GOOD AGREEMENT DEVELOPING A CLOSED 500 MB LOW NEAR SRN CAL BY THURS. THE LOW THEN LIFTS TOWARDS THE 4 CORNERS WHILE BECOMING AN OPEN WAVE. THE WAVE WILL THEN PUSH ACROSS THE PLAINS TO END THE WEEK. THIS WILL BRING A RETURN OF THE ACTIVE WEATHER...AND WILL HAVE POPS TOWARDS THE END OF THE EXTENDED PERIOD. STILL HAVE SOME LOCATION AND TIMING ISSUES TO IRON OUT WHICH IS TYPICAL THIS FAR OUT SO POPS KEPT BELOW 50 PERCENT FOR NOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1228 PM CDT SAT APR 18 2015 LARGE UPPER LEVEL LOW CONTINUES TO MOVE ONLY VERY SLOWLY ACROSS EASTERN COLORADO. EXPECT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO DEVELOP AS A RESULT THIS AFTERNOON AND TONIGHT. THE BEST CONCENTRATION OF SHOWERS AND STORMS WILL BE ACROSS CENTRAL AND SOUTHWEST NEBRASKA...INCLUDING THE KLBF TAF SITE. LATE TONIGHT A COLD FRONT WILL QUICKLY MOVE SOUTHEAST THROUGH THE AREA...THIS WILL BRING MVFR AND POSSIBLE IFR CEILINGS WITH IT FROM AROUND 07Z TO 16Z SUNDAY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
314 PM CDT SAT APR 18 2015 .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 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 315 PM CDT SAT APR 18 2015 A COLD FRONT ACROSS WESTERN NORTH DAKOTA THIS AFTERNOON WILL MOVE ACROSS THE CENTRAL THIS EVENING AND MERGE WITH A LOW DEVELOPING ACROSS EASTERN SOUTH DAKOTA TONIGHT. SCATTERED RAIN SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS WESTERN NORTH DAKOTA THIS AFTERNOON...WITH MORE WIDESPREAD RAIN SHOWERS POSSIBLE AT KMOT/KBIS/KJMS THIS EVENING AND TONIGHT. EMBEDDED MVFR CONDITIONS POSSIBLE IN RAIN. && .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. && $$ SHORT TERM...AYD LONG TERM...AJ AVIATION...AYD FIRE WEATHER...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1230 PM CDT SAT APR 18 2015 .UPDATE... ISSUED AT 1230 PM CDT SAT APR 18 2015 NO SIGNIFICANT CHANGES WITH THIS UPDATE AS THE 12 UTC DETERMINISTIC SUITE AND 13-16 UTC HRRR ITERATIONS MATCH WELL TO OBSERVED TRENDS THROUGH 17 UTC OF RAIN SLOWLY PROPAGATING NORTH FROM SOUTH DAKOTA IN ASSOCIATION WITH THE UPPER LEVEL LOW AND RAIN SHOWER ACTIVITY JUST BEGINNING ACROSS EASTERN MONTANA ALONG THE COLD FRONT. UPDATE ISSUED AT 920 AM CDT SAT APR 18 2015 WILL CONTINUE TO FAVOR THE TRENDS OF THE 10-13 UTC HRRR ITERATIONS WHICH KEEP THE BAND OF PRECIPITATION ACROSS SOUTHERN SOUTH DAKOTA AND EASTERN NEBRASKA IN ASSOCIATION WITH THE UPPER LEVEL LOW FOR THE MOST PART TO THE SOUTH OF NORTH DAKOTA UNTIL 22-24 UTC THIS EVENING GIVEN DRY EAST-SOUTHEASTERLY LOW LEVEL FLOW PRECEDING THIS SYSTEM. BETTER CHANCES FOR SHOWER ACTIVITY THIS AFTERNOON ARE ACROSS THE WEST AS A COLD FRONT ACROSS EASTERN MONTANA THIS MORNING ENTERS WESTERN NORTH DAKOTA THIS AFTERNOON. DID ADD A MENTION OF THUNDERSTORMS TO THE WEST ALONG THE FRONT WITH SOME WEAK INSTABILITY DEPICTED ON THE 06 UTC NAM/GFS BUFR SOUNDINGS. UPDATE ISSUED AT 626 AM CDT SAT APR 18 2015 A FEW WEAK RADAR ECHOS ARE TRYING TO SNEAK INTO THE SOUTH CENTRAL PART OF THE STATE...THOUGH THESE APPEAR WEAK AND DOUBTFUL MORE THAN A FEW SPRINKLES COULD BE HITTING THE GROUND. WITH THAT SAID...LATEST GUIDANCE IS STILL ON TRACK FOR SHOWERS TO BE ON THE INCREASE LATE DAY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 424 AM CDT SAT APR 18 2015 MARGINAL FIRE WEATHER CONDITIONS AND CHANCES FOR MUCH NEEDED RAIN WILL HIGHLIGHT THE SHORT TERM. AS TWO UPPER LEVEL LOWS CONVERGE OVER THE NORTHERN PLAINS THROUGH SATURDAY...MOISTURE TRANSPORT FROM THE SOUTH AND ATMOSPHERIC INSTABILITY WILL CREATE WIDESPREAD CHANCES FOR RAIN. SOUTHERN AND EASTERN AREAS OF THE STATE ARE EXPECTED TO HAVE THE GREATEST CHANCES FOR SUBSTANTIAL RAIN...CONCLUDED THROUGH GOOD AGREEMENT WITH THE CURRENT 00Z MODEL SUITE. CHANCES FOR RAIN ARE FORECAST TO INITIATE THROUGH SATURDAY AFTERNOON AND PERSIST INTO SUNDAY MORNING. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 424 AM CDT SAT APR 18 2015 ON SUNDAY...DEEPENING TROUGH CLOSES OFF OVER MANITOBA WHILE LOW OVER THE SOUTHERN PLAINS WASHES INTO THE NORTHERN SYSTEM. PRECIPITATION CHANCES WILL CONTINUE PRIMARILY OVER CENTRAL AND NORTHERN NORTH DAKOTA...THOUGH MOISTURE WRAPPING AROUND THE BACK SIDE OF THE SYSTEM WILL STILL KEEP LOWER PRECIPITATION CHANCES FURTHER SOUTH AND WEST. GUSTY WINDS EXPECTED THOUGH THE DAY IN TIGHT PRESSURE GRADIENT WITH SURFACE LOW PUSHING INTO THE MIDWEST. WINDS WILL REMAIN BREEZY OVERNIGHT WITH LOW RAIN/SNOW CHANCES LINGERING OVER CENTRAL NORTH DAKOTA. UPPER LOW PUSHES ALONG THE MINNESOTA/ONTARIO BORDER ON MONDAY. THIS WILL KEEP LOW PRECIPITATION CHANCES GOING PRIMARILY OVER THE JAMES RIVER VALLEY. WITH TIGHT PRESSURE GRADIENT ON THE BACK SIDE OF THIS SYSTEM...WILL KEEP THE STRONGER WINDS MAINLY OVER CENTRAL NORTH DAKOTA...DECREASING TOWARDS THE WEST. 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 A FEW SHOWERS POSSIBLE ON TUESDAY AS A FAST MOVING WAVE SLIDES THROUGH THE FLOW...DRY WEATHER IS EXPECTED. TEMPERATURES WILL REMAIN A BIT BELOW AVERAGE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1225 PM CDT SAT APR 18 2015 A COLD FRONT ACROSS EASTERN MONTANA THIS MORNING WILL ENTER WESTERN NORTH DAKOTA THIS AFTERNOON AND MERGE WITH A LOW DEVELOPING ACROSS EASTERN SOUTH DAKOTA TONIGHT. SCATTERED RAIN SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS WESTERN NORTH DAKOTA THIS AFTERNOON...WITH MORE WIDESPREAD RAIN SHOWERS POSSIBLE AT KMOT/KBIS/KJMS THIS EVENING AND TONIGHT. EMBEDDED MVFR CONDITIONS POSSIBLE IN RAIN. && .FIRE WEATHER... ISSUED AT 424 AM CDT SAT APR 18 2015 RELATIVE HUMIDITY VALUES ARE PROJECTED TO BE IN THE LOWER TO MID 20S THIS AFTERNOON OVER CENTRAL NORTH DAKOTA. WITH SOUTHERLY WINDS OF AROUND 10 TO 20 MPH...NEAR CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE. OVER WESTERN NORTH DAKOTA...A COLD FRONT WILL PUSH INTO THE AREA BRINGING A WIND SHIFT TO THE NORTHWEST. BEHIND THE FRONT...WINDS WILL INCREASE TO AROUND 25 MPH. RELATIVE HUMIDITY VALUES WILL BE HIGHER OVER THIS REGION...INCREASING BEHIND THE FRONT...THOUGH THIS STILL MAY BRING A PERIOD OF NEAR CRITICAL FIRE WEATHER CONDITIONS. WETTING RAINS POSSIBLE TONIGHT...ESPECIALLY OVER THE EASTERN HALF OF THE STATE. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...AC LONG TERM...JJS AVIATION...AYD FIRE WEATHER...AC/JJS
AREA FORECAST DISCUSSION
NWS NORMAN OK6
1150 AM CDT SAT APR 18 2015 .AVIATION... EXPECT VFR CEILINGS THROUGH THE AFTN WITH A ROUND OF TSTMS TO AFFECT MOST TAF SITES LATE THIS AFTN INTO THIS EVENING. A COLD FRONT WILL BRING A WIND SHIFT FROM NW TO SE OVERNIGHT INTO SUNDAY MORNING. SOME GUSTS TO NEAR 30KTS POSSIBLE IN NORTHWEST OK. 30 && .PREV DISCUSSION... /ISSUED 646 AM CDT SAT APR 18 2015/ .DISCUSSION... AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW. && .AVIATION... HAVE LOW CONFIDENCE OF VFR TO LIFR CONDITIONS IN WESTERN OKLAHOMA THROUGH 21Z AS WELL AS LOW CONFIDENCE WITH TSRA TIMING/COVERAGE AFTER 19Z. CONDITIONS WILL BOUNCE BETWEEN VFR AND LIFR WITH BR/FG ACROSS WESTERN OKLAHOMA THROUGH 21Z. THE WORST CONDITIONS MAY BE NEAR KCSM AND KHBR THROUGH 15Z. IFR CONDITIONS MAY AFFECT KSPS AND KLAW AS WELL THROUGH 15Z...BUT DID NOT MENTION THINKING THESE LOWER CONDITIONS WILL STAY WEST OF THESE SITES. HAVE HIGH CONFIDENCE ALL SITES WILL BE VFR BY 21Z. ISO-NUM TSRA WILL FORM AND AFFECT MANY TAF SITES AFTER 19Z. USED VCTS/TEMPOS AT MOST SITES EXCEPT KCSM AND KHBR WHERE CONFIDENCE OF STORMS IS TOO LOW TO MENTION. BRIEF VARIABLE GUSTY WINDS... HAIL...AND MVFR OR LOWER CONDITIONS ARE POSSIBLE WITH THE STRONGEST STORMS. MOST STORMS WILL BE EAST OF ALL TAF SITES BY 04Z. ADDITIONAL MVFR/IFR CONDITIONS MAY DEVELOP AFTER 06Z BUT DID NOT MENTION DUE TO LOW CONFIDENCE OF OCCURRENCE. MBS && .PREV DISCUSSION... /ISSUED 419 AM CDT SAT APR 18 2015/ DISCUSSION... SEVERE THUNDERSTORM POTENTIAL THIS AFTERNOON AND EVENING IS THE MAIN CONCERN. RAIN CHANCES THIS MORNING LOOK TO BE MAINLY CONFINED TO LOCATIONS EAST OF I-35 WHERE MOST LATEST RADAR ECHOES WERE OCCURRING FROM A WEAK IMPULSE ROTATING AROUND A MID/UPPER LOW IN SOUTHERN COLORADO. NO SEVERE STORMS ARE EXPECTED WITH THIS ACTIVITY...JUST SOME LOCALIZED HEAVY RAIN. MOST OF THIS ACTIVITY MAY END BY 8 AM IF THE LATEST HRRR RUNS ARE CORRECT. MOST LOCATIONS WILL REMAIN DRY THIS MORNING. ADDED PATCHY FOG MENTION THROUGH 11 AM THIS MORNING ACROSS PARTS OF WESTERN OKLAHOMA AND WESTERN NORTH TEXAS WHERE SOME PARTIAL CLEARING...ABUNDANT LOW LEVEL MOISTURE...AND LATEST HRRR RUNS FAVOR SOME DEVELOPMENT. DOUBT IT WILL GET TOO WIDESPREAD OR DENSE. THIS AFTERNOON AND EVENING...ISOLATED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE AREA. CAPPING WILL BE RATHER WEAK. WITH MORE SUN COMPARED TO YESTERDAY...THINK CONVECTIVE TEMPERATURES WILL BE REACHED RATHER EASILY IN THE 2 TO 5 PM TIME FRAME. FIRST DEVELOPMENT MAY BE FOCUSED IN WESTERN OKLAHOMA AND WESTERN NORTH TEXAS NEAR A DEVELOPING DRYLINE. WENT NEAR GUIDANCE RAIN CHANCES. EXACTLY WHERE AND WHEN STORMS OCCUR REMAINS TRICKY TODAY AND TONIGHT. IN REGARDS TO SEVERE POTENTIAL THIS AFTERNOON AND EVENING... BELIEVE THERE WILL BE SOME SEVERE STORMS WITH LARGE HAIL AS THE MAIN CONCERN. THE AIR WILL BE MODERATELY UNSTABLE WITH MLCAPE 1500-2500 J/KG. STRONG 0-6 KM SHEAR 30-50 KT SUPPORTS SUPERCELLS AND MULTICELLS. STRONG 0-3 KM SHEAR VALUES 25-45 KT AND VERY COLD MID LEVELS WITH 500 MB TEMPERATURES AROUND -18C COULD SUPPORT VERY LARGE HAIL IN SOME CELLS AS LONG AS CONVECTION IS NOT TOO WIDESPREAD. SOME DAMAGING WINDS MAY OCCUR AS WELL IF STORMS CAN ORGANIZE INTO CLUSTERS AND LINES. TORNADO POTENTIAL APPEARS TO BE LIMITED DUE TO WEAK LOW LEVEL SHEAR...THOUGH NOTICED THE LATEST RAP13 INDICATED STRONGER LOW LEVEL WINDS POSSIBLY DEVELOPING IN SOUTHWESTERN OKLAHOMA IN THE 5 TO 9 PM TIME FRAME WHICH MAY INCREASE THIS POTENTIAL. WILL CLOSELY MONITOR. LOCALLY HEAVY RAINFALL MAY AGAIN OCCUR LATE THIS AFTERNOON AND TONIGHT...THOUGH STORM MOTIONS WILL BE FASTER WHICH MAY LIMIT THE DURATION OF HEAVY RAINFALL IN ONE GIVEN LOCATION. MOST STORMS WILL MOVE INTO EASTERN OKLAHOMA AFTER MIDNIGHT TONIGHT...ALLOWING FOR MOIST AND COOL CONDITIONS. WOULD NOT BE SURPRISED IF SOME FOG FORMED...BUT DID NOT MENTION DUE TO LOW CONFIDENCE. ON SUNDAY...A FEW SHOWERS AND STORMS MAY LINGER MAINLY OVER NORTHERN OKLAHOMA...THOUGH APPEARS THE SEVERE POTENTIAL WILL SHIFT IN FAR EASTERN OKLAHOMA AND POINTS EAST. WITH LINGERING WEAK INSTABILITY AND COLD MID/UPPER LEVELS...A FEW STORMS WITH SMALL HAIL COULD OCCUR. BREEZY CONDITIONS WILL DEVELOP. THERE IS AN OUTSIDE CHANCE WINDS COULD APPROACH ADVISORY CRITERIA WITH GUSTS OVER 40 MPH IN NORTHWEST OKLAHOMA. WENT WITH THE WARMER SIDE OF GUIDANCE TEMPERATURES THINKING SOME SUN WILL OCCUR...ESPECIALLY EARLY IN THE DAY. SUNDAY NIGHT THROUGH FRIDAY...A WET PATTERN MAY CONTINUE WITH RAIN CHANCES REMAINING IN THE FORECAST MOST DAYS. THERE ARE SOME MODEL DISCREPANCIES WITH WEATHER FEATURES...THUS FORECAST CONFIDENCE REMAINS LOW. SOME STRONG TO SEVERE STORMS MAY OCCUR TUESDAY THROUGH FRIDAY WITH NEARBY MOISTURE AND INSTABILITY. MBS && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 25/17/17
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1243 PM CDT SAT APR 18 2015 .UPDATE... ISSUED AT 1030 AM CDT SAT APR 18 2015 WITH DRY AIR IN PLACE...ERODING NORTHERN EXTENT OF SHOWER ACTIVITY...REDUCED POPS/QPF NORTH OF THE MAIN BAND OF PRECIPITATION FOR THE AFTERNOON IN LINE WITH LATEST HRRR AND RUC GUIDANCE. LATEST NAM IS IN LINE WITH CURRENT FORECAST AFTER 00Z. HRRR COLUMN MAX REF DOES LOOK LIKE A WEAK FEW CONVECTIVE CELLS FORM OVER THE CWA TODAY SO WILL LEAVE MENTION OF THUNDER IN. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 327 AM CDT SAT APR 18 2015 PRECIPITATION CHANCES OVER THE NEXT 24 HOURS...AND WINDS SUNDAY AND MONDAY WILL BE THE FORECAST CHALLENGES. A FAIRLY DRY AIR MASS REMAINS IN PLACE ACROSS MOST OF THE CWA THIS MORNING WITH DEW POINTS MAINLY IN THE UPPER 20S. HIGHER DEW POINTS ARE ADVECTING NORTHWESTWARD INTO WESTERN SOUTH DAKOTA WHERE VALUES IN THE 40S. THESE HIGHER DEW POINTS...ALONG WITH SOME SHOWERS AND THUNDERSTORMS WILL SLOWLY TRACK NORTHWARD THROUGH THE DAY AS AN UPPER LEVEL LOW PRESSURE SYSTEM MOVES ACROSS THE CENTRAL PLAINS. VARIOUS HI-RES MODELS SUGGEST SHOWERS WOULD REACH HIGHWAY 212 AROUND 18Z...AND HIGHWAY 12 BETWEEN 21-0Z THIS AFTERNOON. HAVE TRIED TO DELAY POPS IN THE NORTHERN AND FAR NORTHEASTERN PORTION OF THE CWA UNTIL AFTER 21Z. PCPN MAY NOT REACH THE SISSETON/WHEATON AREA UNTIL AFTER 0Z SUNDAY. TONIGHT THROUGH SUNDAY MORNING...MODELS SUGGEST THE LOW PRESSURE SYSTEM WILL MERGE WITH A NORTHERN STREAM TROUGH...WHICH COULD BRING BETTER CHANCES FOR SHOWERS. THE NORTHERN STREAM WILL LIKELY BRING GUSTY NORTHWESTERLY WINDS TONIGHT ALONG A SURFACE COLD FRONT. A FAIRLY DRY AIR MASS WILL FOLLOW THIS COLD FRONT WITH PCPN LIKELY ENDING FROM WEST TO EAST BY THE MID MORNING HOURS ON SUNDAY. BY SUNDAY AFTERNOON COLD AIR ADVECTION WILL DEVELOP WITH GUSTY NORTHWESTERLY WINDS AND INSTABILITY SHOWERS POSSIBLE. WINDS MAY EXCEED ADVISORY LEVELS...ESPECIALLY IN THE WESTERN HALF OF THE CWA. A TIGHT PRESSURE GRADIENT OVER THE REGION WILL PROMOTE GUSTY NORTHWESTERLY WINDS ON MONDAY AS WELL. COLD AIR ALOFT...ALONG WITH CAPE VALUES AROUND 100 J/KG COULD PRODUCE ISOLATED SHOWERS IN THE FAR EASTERN PORTION OF THE CWA MONDAY AFTERNOON. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 327 AM CDT SAT APR 18 2015 NOT MUCH CHANGE NOTED IN THE LONGER RANGE MODEL OUTPUT...COMPARED TO 24 HOURS. PRECIPITATION CHANCES ARE PRETTY MUCH DONE AND GONE MONDAY NIGHT...WITH A MAINLY DRY FORECAST THERE-AFTER /DRY AND COOL NORTHWEST FLOW ESTABLISHING OVER THE NORTHERN PLAINS ALOFT/. BY THURSDAY...THERE IS A RATHER SLIM CHANCE THAT ENERGY TRYING TO LIFT NORTH-NORTHEAST TOWARD THE NORTHERN PLAINS COULD INTRODUCE SOME DEFORMATION ZONE-FORCED LIGHT PRECIP POTENTIAL ACROSS THE SOUTHWESTERN FORECAST ZONES...PRIOR TO EXPERIENCING THE SHEARING EFFECTS OF NORTHWEST /POLAR JET/ FLOW ALOFT. SUPERBLEND CONTINUES TO PRODUCE SOME LOW PROBABILITIES FOR PRECIPITATION THURSDAY NIGHT/FRIDAY THOUGH. UNDER THIS NORTHWEST FLOW ALOFT REGIME...LOW LEVEL FLOW IS PERSISTENTLY ADVECTING COOL/DRY AIR DOWN OUT OF CANADA ON NORTHEASTERLY BOUNDARY LAYER MIXING WINDS. TEMPERATURES DURING THE EXTENDED FORECAST PERIOD SHOULD BE RUNNING NEAR NORMAL TO PERHAPS A FEW DEGREES BELOW NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1236 PM CDT SAT APR 18 2015 A LOW PRESSURE SYSTEM WILL BRING SOME SHOWERS TO THE REGION THIS AFTERNOON AND EVENING. VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD EXCEPT PERHAPS SOME BRIEF AND TRANSIENT MVFR CIGS IN HEAVIER SHOWERS NEAR KMBG/KATY THIS EVENING. AS THE LOW EXITS SHOWERS WILL TAPER OFF BY 9Z AND NORTHWEST WINDS WILL INCREASE TO 15 TO 25 KTS WITH HIGHER GUSTS. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...CONNELLY SHORT TERM...SD LONG TERM...DORN AVIATION...WISE
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
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. && $$ 31
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
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. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 62 76 60 68 / 100 70 60 40 CLARKSVILLE 62 74 58 66 / 100 70 60 40 CROSSVILLE 61 71 59 67 / 100 80 60 60 COLUMBIA 62 75 60 67 / 100 60 60 40 LAWRENCEBURG 63 75 59 68 / 100 50 60 40 WAVERLY 62 75 59 69 / 100 60 60 30 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 11
AREA FORECAST DISCUSSION
NWS AMARILLO TX
521 PM CDT SAT APR 18 2015 .UPDATE... WEST TEXAS MESONET AND SCHOOL NET OBSERVATIONS SHOW A CONTINUED DECREASE IN SURFACE DEW POINTS AND VEERING OF SURFACE WINDS ACROSS THE FAR EASTERN PORTION OF THE TEXAS PANHANDLE. SPC RAP MESOANALYSIS HAS RESPONDED BY DEPICTING MUCH HIGHER LCL HEIGHTS THAT ARE LESS FAVORABLE FOR TORNADOES. A MORE FAVORABLE ENVIRONMENT EXISTS FURTHER EAST INTO OKLAHOMA WHERE SURFACE WINDS REMAINED BACKED AND AT LEAST SHALLOW LOW LEVEL MOISTURE /DEW POINTS IN THE MID TO UPPER 50S/ IS PRESENT. A FAIRLY POTENT VORT MAX IS MOVING ACROSS THE TEXAS PANHANDLE NOW AS SEEN ON WATER VAPOR LOOP AND THIS MAY RESULT IN AN UPTICK IN CONVECTION OVER THE NEXT COUPLE OF HOURS. HAIL AND WIND ARE STILL POSSIBLE WITH THE STRONGEST STORMS AS ENOUGH INSTABILITY REMAINS INTO EARLY EVENING. WILL CONTINUE TO MONITOR TRENDS IN THE OBSERVATIONS...ESPECIALLY LATER THIS EVENING WHEN MIXING SUBSIDES AND THE DRYLINE POSSIBLY SHIFTS WESTWARD SOME. THE BEST CHANCE OF BETTER LOW LEVEL MOISTURE RETURNING TO THE FORECAST AREA WILL BE ACROSS WHEELER AND COLLINGSWORTH COUNTIES. BRB && .PREV DISCUSSION... /ISSUED 221 PM CDT SAT APR 18 2015/ DISCUSSION... EARLY THIS AFTERNOON A DEEP CLOSED LOW WAS SITUATED OVER EASTERN COLORADO AND SLOWLY MOVING EAST. A BAND OF CLOUDS ASSOCIATED WITH A RELATIVELY POTENT VORT LOBE ROTATING AROUND THE MID-UPPER LOW WAS EVIDENT IN IR/VIS SATELLITE. SURFACE OBSERVATIONS SHOW LIGHT RAIN BENEATH THIS BAND OF CLOUDS AT CLAYTON NEW MEXICO AND PRESUMABLY FURTHER SOUTH-SOUTHWEST EAST OF TUCUMCARI INTO THE FAR WESTERN TEXAS PANHANDLE WHERE LIGHT ECHOS WERE PRESENT ON REGIONAL RADAR MOSAIC. FURTHER EAST ACROSS THE TEXAS AND OKLAHOMA PANHANDLE LOW CLOUDS HAVE DIMINISHED AND/OR SHIFTED INTO OKLAHOMA AS SURFACE WINDS CONTINUE TO VEER SLIGHTLY. SHALLOW LOW LEVEL MOISTURE SEEN ON 12Z KAMA SOUNDING REMAINS ACROSS THE EASTERN PANHANDLES EAST OF A DIFFUSE DRYLINE. THERE REMAINS SOME UNCERTAINTY ON THE POSITION OF THE DRYLINE THAT IS EXPECTED TO SHARPEN THIS AFTERNOON AS DIABATIC HEATING/MIXING COMMENCES. USING SHORT RANGE MODEL FORECAST SOUNDINGS AS GUIDANCE ON THE DEPTH OF MOISTURE OFF THE CAPROCK AND ESPECIALLY FURTHER EAST NEAR THE OKLAHOMA BORDER LEADS TO FAIRLY HIGH CONFIDENCE ON THE PREVIOUS FORECAST WHICH RELEGATES ANY SUBSTANTIAL DEEP CONVECTION TO NEAR OR JUST EAST OF THE OKLAHOMA STATE LINE LATER THIS AFTERNOON. LOW LEVEL MOISTURE IS DEEPER FROM THERE EASTWARD INTO OKLAHOMA AND THUS DRYLINE CIRCULATION THAT DEVELOPS STANDS A BETTER CHANCE AT INITIATING CONVECTION THERE THAN WAS THE CASE FURTHER WEST YESTERDAY. SO THROUGH THE LATE AFTERNOON AND EVENING THERE IS ONLY A LOW PROBABILITY OF ISOLATED-SCATTERED CONVECTION ACROSS THE EXTREME EASTERN PORTION OF THE PANHANDLES WITH BETTER CHANCES OUT OF THE FORECAST AREA ACROSS WESTERN OKLAHOMA. IF THE ABOVE ASSESSMENT IS MISPLACED SLIGHTLY EAST THAN ANY STORM THAT DOES DEVELOP ON OUR SIDE OF THE STATE LINE WOULD HAVE THE POTENTIAL TO BECOME SEVERE DUE TO MODERATE INSTABILITY AND SUFFICIENT DEEP LAYER SHEAR OF AROUND 30 KNOTS FOR STORM ORGANIZATION/PERSISTENCE. LARGE HAIL WOULD BE THE PRIMARY THREAT INTO THE EVENING GIVEN STEEP MID LEVEL LAPSE RATES OWING TO THE APPROACHING MID-UPPER LOW. WILL CONTINUE TO MONITOR TRENDS IN SURFACE OBSERVATIONS AND DRYLINE EVOLUTION THROUGHOUT THE AFTERNOON. FURTHER WEST OF THE DRYLINE...DEEP MIXING WILL OCCUR GENERALLY EAST OF THE AFOREMENTIONED BAND OF LOW-MID CLOUDS NOW ENTERING THE TEXAS PANHANDLE. CU FIELD IS INCREASING IMMEDIATELY AHEAD OF THIS. BASES SHOULD BECOME RELATIVELY HIGH AS MIXED LAYER DEEPENS THROUGH THE AFTERNOON. WITH FORCING FROM PREVIOUSLY MENTIONED VORT LOBE CONVECTION MAY BECOME DEEP ENOUGH FOR SHOWERS AND THUNDERSTORMS FOR MUCH OF THE AREA LATER THIS AFTERNOON. IF CONVECTION BECOMES DEEP ENOUGH FOR CHARGE SEPARATION AND LIGHTNING...LIMITED INSTABILITY SHOULD PRECLUDE THE THREAT OF SEVERE THUNDERSTORMS. PROGNOSTICATIONS FROM THE HI-RES CONVECTION ALLOWING GUIDANCE INCLUDING THE HRRR AND TTU WRF SEEM TO LINE UP WELL WITH THE ABOVE THINKING. AS THE MID-UPPER LOW CONTINUES TO SHIFT EAST A COLD FRONT WILL MOVE THROUGH THE AREA TONIGHT. MODEL GUIDANCE IS IN AGREEMENT IN AN EVOLUTION OF THE LOW INTO A MORE OPEN AND PROGRESSIVE WAVE THAT WILL BE EAST OF THE AREA BY TOMORROW AFTERNOON. AN AREA OF MOISTURE ON THE BACK SIDE OF THIS EVOLVING SHORTWAVE TROUGH FAVORABLY TIMED WITH PEAK HEATING SHOULD BE ENOUGH FOR EXTENSIVE CUMULUS DEVELOPMENT DURING THE AFTERNOON POSSIBLY ENOUGH FOR BROKEN SKY CONDITIONS ESPECIALLY ACROSS THE EASTERN PORTION OF THE AREA. DEPTH OF CONVECTION IN ROUGHLY THE NORTHEAST THIRD WILL NEED TO BE MONITORED AS IT MAY BECOME SUFFICIENT FOR A FEW SHOWERS GIVEN RESIDUAL COOL MID LEVEL TEMPERATURES AND RELATIVELY HIGH TQ INDEX VALUES. ADJUSTED LOW POPS ON SUNDAY AFTERNOON TO EXTEND A BIT FURTHER SOUTH AND WEST TO ACCOUNT FOR THIS. EARLY NEXT WEEK A SPLIT UPPER FLOW PATTERN WILL EXIST WITH STRONG PERIODICALLY PERTURBED WESTERLY SOUTHERN BRANCH JUST SOUTH OF US AND NORTHWESTERLY NORTHERN BRANCH ACROSS THE CENTRAL PLAINS. MEAN RIDGING WILL BE PRESENT OVER THE WESTERN STATES. GRADUALLY INCREASING 500 MB HEIGHTS AND A SLIGHTLY MORE AMPLIFIED PATTERN WILL EVOLVE THROUGH THE WEEK ESPECIALLY AS ANOTHER CLOSED LOW DEVELOPS AND DEEPENS OVER THE SOUTHWESTERN CONUS BY THURSDAY. AS THIS MOVES EAST THIS WILL PROBABLY RESULT IN ANOTHER CONVECTIVELY ACTIVE PATTERN FOR THE LATTER HALF OF THE WEEK. AS IS TYPICALLY THE CASE AT THAT TIME RANGE MODEL GUIDANCE DIFFERS IN TIMING AND AMPLITUDE BUT THE SIGNAL IS THERE FOR A SCENARIO FAVORING A NORTH/WEST SURGE OF LOW LEVEL MOISTURE AND FORCING FOR ASCENT RESULTING IN ABOVE CLIMO PRECIPITATION PROBABILITIES AND THE POSSIBILITY OF SEVERE THUNDERSTORMS BY MID AND ESPECIALLY LATE WEEK. EVEN BEFORE THEN THERE WILL BE A FEW OPPORTUNITIES FOR PRECIPITATION EARLIER IN THE WEEK AS DIFFICULT TO RESOLVE SMALL SHORTWAVE TROUGHS WITHIN MEAN WEST-NORTHWESTERLY FLOW CROSS THE AREA. CONVECTION MAY EMANATE FROM THE HIGHER TERRAIN OF COLORADO AND NEW MEXICO AND MOVE INTO THE PANHANDLES LATE MONDAY AND AGAIN LATE TUESDAY...ALTHOUGH THIS FORECAST WILL BE LESS DETERMINISTIC WITH TIMING OF HIGHER PROBABILITIES OF PRECIPITATION AND MORE BROAD BRUSH GIVEN INHERENT UNCERTAINTIES OF THIS TYPE PATTERN. BRB && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 15/17
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
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 && .PREV DISCUSSION... /ISSUED 340 PM CDT SAT APR 18 2015/ DISCUSSION... THE UPPER LOW OVER EASTERN CO WILL OPEN UP AND SHEAR OUT OVER THE PLAINS DURING THE NEXT DAY OR TWO. A COUPLE OF SHORTWAVE TROUGHS MOVING OVERHEAD WILL BRING SCATTERED THUNDERSTORMS ACROSS SE TX DURING A COUPLE OF EPISODES TONIGHT...THE FIRST DURING THE LATE AFTERNOON AND EARLY EVENING AND THE SECOND FROM LATE EVENING INTO THE OVERNIGHT PERIOD. CANNOT RULE OUT THE POSSIBILITY OF AN ISOLATED OR STRONG THUNDERSTORM. ALTHOUGH THE MAIN STORM ACTION WELL OFFSHORE OF THE COAST HAS BEEN STEALING MOST OF THE INFLOW MOISTURE...THE LATEST SATELLITE TRENDS INDICATE THAT THE STORMS NEAR MATAGORDA BAY WERE BEGINNING TO EXHIBIT COOLING CLOUD TOPS. THERE IS ALSO A SLIGHT CHANCE THAT THE STORMS OVER THE FAR SOUTHWESTERN SET OF COUNTIES MAY CONTAIN LOCALLY HEAVY RAINFALL DURING THE REMAINING AFTERNOON HOURS. THE SECOND ROUND OF STORMS WAS BEING FORECASTED BY THE HRRR AND TEXAS TECH WRF TO MOVE OVER THE NORTHWESTERN AND NORTHERN SET OF COUNTIES BETWEEN ABOUT 9 PM AND 2 AM OR SO. RAP FORECAST SOUNDING SHOW THE POTENTIAL FOR ISOLATED STRONG OR SEVERE STORMS WITH THESE AS WELL. HIGH PRESSURE SHOULD THEN BUILD OVERHEAD SUNDAY AND MONDAY AND LOWER THE RAIN CHANCES. BOTH THE GFS AND ECMWF AGREE WITH ONSHORE WINDS AND RAIN CHANCES RETURNING BY WEDNESDAY. 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 PREV DISCUSSION... /ISSUED 1248 PM CDT SAT APR 18 2015/ AVIATION... SAT IMAGERY SUGGESTS INLAND PORTIONS OF SE TX SHOULD START SEEING SOME INTERMITTENT BREAKS OF SUN. ELSEWHERE...EXPECT TO SEE IMPROVING CIG HEIGHTS IN THE NEXT COUPLE HOURS. THERE IS A SFC BOUNDARY NEAR THE COAST...SO ADDITIONAL HEATING ALONG WITH APPROACHING S/W FROM MID TX COAST SHOULD ALLOW FOR AT LEAST SOME SCT TSRA TO DEVELOP THIS AFTN - ESP SOUTH OF A COLUMBUS-LIBERTY LINE. (THIS IS ROUGHLY THE SAME LOCATIONS THAT SAW SOME SIG WX YDAY SO WILL NEED TO KEEP A CLOSE EYE ON THINGS.) AREAS FURTHER N WILL NEED TO KEEP AN EYE ON NW TX. MODELS ARE POINTING TOWARD A DEVELOPING LINE OF SHRA/TSRA OUT THERE THIS AFTN...POSSIBLY MAKING IT ESE TOWARD SE TX LATE EVNG & OVERNIGHT. WILL SEE HOW THIS ALL PLAYS OUT, BUT WENT AHEAD AND THREW THE POTENTIAL OF THIS OCCURRING IN THE 9-2AM TIMEFRAME IN THE CLL, UTS, CXO TAFS. CONSIDERABLE UNCERTAINTY IN THIS ATTM BUT FEEL IT`S ENOUGH TO BEGIN MENTIONING. 47 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 63 85 56 75 54 / 50 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 EL PASO TX/SANTA TERESA NM
251 PM MDT SAT APR 18 2015 .SYNOPSIS... WINDS WILL TAPER OFF AFTER SUNSET THIS EVENING AS TEMPERATURES COOL ACROSS THE BORDERLAND. DAYTIME CLOUDS WILL DISSOLVE LEAVING SKIES MOSTLY CLEAR OVERNIGHT. SUNDAY WILL BE GENERALLY DRY AND SUNNY AS A LOW PRESSURE SYSTEM BEGINS TO EXIT EAST. TEMPERATURES WILL WARM ABOUT 5 DEGREES AND WINDS WILL BE NOTICEABLY LIGHTER. JUST A BIT OF LINGERING MOISTURE ALOFT MAY ALLOW FOR A STRAY ELEVATED THUNDERSTORM OVER THE MOUNTAINS IN THE AFTERNOON HOURS. THE WEATHER REPEATS MONDAY. TUESDAY ONWARD STRONGER WINDS RETURN FOR EACH AFTERNOON WITH THURSDAY LOOKING THE STRONGEST FOR THE WEEK. GENERALLY DRY CONDITIONS LOOK TO HOLD FOR THE WEEK AHEAD BUT A PACIFIC LOW PRESSURE SYSTEM DOES TRACK ACROSS THE REGION THURSDAY TO BRING INCREASED CLOUDS...AND MAYBE A STRAY SHOWER OR STORM. && .DISCUSSION... LARGE UPPER-LEVEL LOW PRESSURE SYSTEM SPINS OVER E CO. IT IS S-L-O-W-L-Y DRIFTING EAST TOWARDS KS. WE SIT UNDER THE SOUTHERN PERIPHERY OF THIS SYSTEM WITH A BIT OF MID-LEVEL MOISTURE AND LARGE-SCALE WEAK FORCING ALOFT. THE RESULT THUS FAR TODAY HAS BEEN TO ROTATE A NICE CU-FIELD OVER THE NORTHERN ZONES FROM THE NW. HOWEVER STILL NO ENHANCED RADAR ECHOS OR LIGHTNING. MOST OF THE CU IS QUITE FLAT. VERY REASONABLE GIVEN THE ACTUAL 12Z SOUNDING AND THE PROG 18-00Z SOUNDINGS. SHOULD BE A SHALLOW LAYER OF MOISTURE WITH PW`S AT 1/3". MODELS DO SHOW THE ATMOSPHERE LEANING TOWARD MARGINALLY UNSTABLE WITH LI`S NEAR 0 AND CAPE LESS THAN 100 J/KG. BOTTOM LINE IS THAT STORM POTENTIAL IS THERE...BUT IT IS MARGINAL WITH ONLY ISOLATED AND WEAK STORMS. BOTH THE HRRR AND WRF MODELS SHOW LATE AFTN/EARLY EVE STORMS OVER SIERRA/OTERO COUNTIES AS DO THE GFS AND NAM. THUS SLIGHT CHANCE WORDING IN THE FORECAST FOR THOSE AREAS FOR THE EVENING HOURS TONIGHT. THREATS/IMPACT WOULD BE STRONG OUTFLOW WIND/LOW VSBY WITH DUST. FOR SUNDAY IT APPEARS WE WILL SEE VERY SIMULAR WEATHER CONDITIONS WITH REGARDS TO TODAY. WITH THE LOW EXITING AND HEIGHTS AND THICKNESSES RISING ALONG WITH LIGHTER WINDS WE SHOULD GAIN ABOUT 5-7 DEGREES ON TEMPS SUNDAY. SUNDAY`S MOISTURE PROFILE RESEMBLES TODAY`S WITH JUST A THIN LAYER OF MODERATELY MOIST AIR ALOFT. WE WILL CONTINUE TO SEE VERY MINOR (WEAK) IMPULSES ALOFT TRACK OVER IN WNW FLOW. WITH OROGRAPHICS WE COULD SEE A FEW MOUNTAIN STORMS...BUT AGAIN ISOLATED AND WEAK. THE LOWLANDS SHOULD STAY DRY. LIGHTER WINDS WILL BE THE BIGGER DEAL AS WINDS DROP BELOW THE BREEZY CATEGORY OF 15 TO 25 MPH. TUESDAY THE PATTERN BECOMES MORE SOUTHWEST ORIENTED AND THAT MEANS WIND WILL BE ON THE INCREASE AGAIN. A DEEPENING PACIFIC TROUGH TO OUR WEST AND A DEEPENING SURFACE TROUGH TO OUR EAST WILL TIGHTEN GRADIENTS AND INCREASE WINDS. TUESDAY AND WEDNESDAY WILL BE DRY... A FEW DEGREES WARMER THAN NORMAL...AND BREEZY. THURSDAY THE WEST COAST LOW PRESSURE SYSTEM ARRIVES WITH WHAT APPEARS TO BE MINIMAL MOISTURE. DESPITE APPEARING TO STRUGGLE WITH IT THE MODELS DO SPIT OUT SOME QPF AND THUS WHAT LOOKS TO BE ISOLATED SHOWERS AND THUNDERSTORMS. FOR NOW WE ARE IGNORING THE SLIGHT PCPN POTENTIAL IN FAVOR WHAT WHAT SHOULD BE A LARGER IMPACT...WIND. THURSDAY LOOKS WINDY BUT CLOUDS MAY TEMPER THE SPEEDS A BIT. FRIDAY THE PACIFIC STORM SYSTEM PASSES AND A MODERATELY WEAK PACIFIC FRONT PUSHES IN TO BRING A SMALL BIT OF COOLING AND LIGHTER WINDS. MODELS SUGGEST A SHORT WAVE RIDGE TO BUILD OVER THE AREA SATURDAY ALLOWING TEMPS TO WARM WITH DRY CONDITIONS. 14-BIRD && .AVIATION...VALID 19/00Z-20/00Z... SCT-BKN CU FIELDS WILL PERSIST INTO THE EARLY EVENING HOURS GENERALLY NORTH OF A SVC-LRU LINE...WITH BASES RUNNING BETWEEN 9-10K FEET. A FEW ISOLATED SHOWERS MAY AFFECT AREAS NORTH OF TCS. ELSEWHERE...MOSTLY CLEAR SKIES WILL PREVAIL. WEST TO NORTHWEST WINDS WILL RANGE 15-20 KNOTS WITH GUSTS 25-30 KNOTS...WITH A FEW HIGHER GUSTS POSSIBLE IN SW NEW MEXICO. WINDS WILL DIMINISH FAIRLY QUICKLY AFTER SUNSET. EXPECT SIMILAR CONDITIONS TOMORROW WITH LOWER WIND SPEEDS. A FEW ISOLATED CONVECTIVE SHOWERS OR EVEN A THUNDERSTORM WILL AFFECT THE AREA TOMORROW...FAVORING AREAS NORTH OF AN LSB-LRU LINE. 25-HARDIMAN && .FIRE WEATHER... WINDS WILL CONTINUE TO SLOWLY INCREASE OVER THEN NEXT FEW HOURS DUE TO A STRONG UPPER LOW OVER COLORADO AND AN INCREASINGLY STRONG PRESSURE GRADIENT. RH VALUES HAVE DROPPED INTO THE LOW AND MID TEENS. CURRENT RED FLAG WARNING LOOKS GOOD AND WILL CONTINUE THROUGH 8 PM. THE UPPER LOW WILL MOVE EAST INTO THE PLAINS TOMORROW...WHILE A WEAK BACKDOOR COLD FRONT STALLS OUT OVER THE AREA. A SECONDARY UPPER LEVEL DISTURBANCE AND THIS FRONT WILL BRING A SLIGHT CHANCE FOR THUNDERSTORMS TO THE HIGHER TERRAIN AREAS SUNDAY AFTERNOON AND EVENING. LIGHTER WINDS WILL PREVAIL EARLY NEXT WEEK...WITH INCREASING SOUTHWEST FLOW BEYOND WEDNESDAY. 25-HARDIMAN && .PRELIMINARY POINT TEMPS/POPS... EL PASO 52 80 54 82 55 / 0 0 0 0 0 SIERRA BLANCA 46 76 49 78 50 / 0 0 0 0 0 LAS CRUCES 45 78 48 79 48 / 0 0 0 0 0 ALAMOGORDO 45 76 49 78 49 / 0 10 10 0 0 CLOUDCROFT 34 56 36 58 39 / 10 10 10 10 0 TRUTH OR CONSEQUENCES 46 76 48 78 48 / 0 10 10 0 0 SILVER CITY 40 71 43 72 43 / 0 0 0 0 0 DEMING 42 80 44 80 45 / 0 0 0 0 0 LORDSBURG 40 79 43 80 43 / 0 0 0 0 0 WEST EL PASO METRO 52 80 55 81 55 / 0 0 0 0 0 DELL CITY 46 79 50 80 50 / 0 0 0 0 0 FORT HANCOCK 48 80 52 82 52 / 0 0 0 0 0 LOMA LINDA 48 73 50 75 52 / 0 0 0 0 0 FABENS 48 80 51 81 51 / 0 0 0 0 0 SANTA TERESA 47 80 50 80 50 / 0 0 0 0 0 WHITE SANDS HQ 50 77 53 79 53 / 0 0 0 0 0 JORNADA RANGE 40 78 44 79 44 / 0 0 0 0 0 HATCH 44 79 46 80 46 / 0 0 0 0 0 COLUMBUS 47 78 50 79 50 / 0 0 0 0 0 OROGRANDE 48 77 52 78 51 / 0 0 0 0 0 MAYHILL 39 64 39 66 43 / 10 10 10 0 0 MESCALERO 38 63 40 66 41 / 10 10 10 0 0 TIMBERON 39 64 41 66 42 / 10 10 10 0 0 WINSTON 36 69 39 72 39 / 10 10 10 0 0 HILLSBORO 42 75 44 77 45 / 0 10 10 0 0 SPACEPORT 41 78 44 79 44 / 0 0 10 0 0 LAKE ROBERTS 37 69 39 71 39 / 10 10 10 0 0 HURLEY 39 73 42 74 42 / 0 0 0 0 0 CLIFF 39 78 40 79 41 / 0 0 0 0 0 MULE CREEK 33 75 37 76 37 / 0 0 0 0 0 FAYWOOD 41 74 44 75 44 / 0 0 0 0 0 ANIMAS 44 79 47 79 47 / 0 0 0 0 0 HACHITA 42 79 45 80 45 / 0 0 0 0 0 ANTELOPE WELLS 42 78 46 79 46 / 0 0 0 0 0 CLOVERDALE 41 74 44 75 44 / 0 0 0 0 0 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR NMZ111-112. TX...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR TXZ055-056. && $$ 14/25
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
340 PM CDT SAT APR 18 2015 .DISCUSSION... THE UPPER LOW OVER EASTERN CO WILL OPEN UP AND SHEAR OUT OVER THE PLAINS DURING THE NEXT DAY OR TWO. A COUPLE OF SHORTWAVE TROUGHS MOVING OVERHEAD WILL BRING SCATTERED THUNDERSTORMS ACROSS SE TX DURING A COUPLE OF EPISODES TONIGHT...THE FIRST DURING THE LATE AFTERNOON AND EARLY EVENING AND THE SECOND FROM LATE EVENING INTO THE OVERNIGHT PERIOD. CANNOT RULE OUT THE POSSIBILITY OF AN ISOLATED OR STRONG THUNDERSTORM. ALTHOUGH THE MAIN STORM ACTION WELL OFFSHORE OF THE COAST HAS BEEN STEALING MOST OF THE INFLOW MOISTURE...THE LATEST SATELLITE TRENDS INDICATE THAT THE STORMS NEAR MATAGORDA BAY WERE BEGINNING TO EXHIBIT COOLING CLOUD TOPS. THERE IS ALSO A SLIGHT CHANCE THAT THE STORMS OVER THE FAR SOUTHWESTERN SET OF COUNTIES MAY CONTAIN LOCALLY HEAVY RAINFALL DURING THE REMAINING AFTERNOON HOURS. THE SECOND ROUND OF STORMS WAS BEING FORECASTED BY THE HRRR AND TEXAS TECH WRF TO MOVE OVER THE NORTHWESTERN AND NORTHERN SET OF COUNTIES BETWEEN ABOUT 9 PM AND 2 AM OR SO. RAP FORECAST SOUNDING SHOW THE POTENTIAL FOR ISOLATED STRONG OR SEVERE STORMS WITH THESE AS WELL. HIGH PRESSURE SHOULD THEN BUILD OVERHEAD SUNDAY AND MONDAY AND LOWER THE RAIN CHANCES. BOTH THE GFS AND ECMWF AGREE WITH ONSHORE WINDS AND RAIN CHANCES RETURNING BY WEDNESDAY. 40 && .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 && .PREV DISCUSSION... /ISSUED 1248 PM CDT SAT APR 18 2015/ AVIATION... SAT IMAGERY SUGGESTS INLAND PORTIONS OF SE TX SHOULD START SEEING SOME INTERMITTENT BREAKS OF SUN. ELSEWHERE...EXPECT TO SEE IMPROVING CIG HEIGHTS IN THE NEXT COUPLE HOURS. THERE IS A SFC BOUNDARY NEAR THE COAST...SO ADDITIONAL HEATING ALONG WITH APPROACHING S/W FROM MID TX COAST SHOULD ALLOW FOR AT LEAST SOME SCT TSRA TO DEVELOP THIS AFTN - ESP SOUTH OF A COLUMBUS-LIBERTY LINE. (THIS IS ROUGHLY THE SAME LOCATIONS THAT SAW SOME SIG WX YDAY SO WILL NEED TO KEEP A CLOSE EYE ON THINGS.) AREAS FURTHER N WILL NEED TO KEEP AN EYE ON NW TX. MODELS ARE POINTING TOWARD A DEVELOPING LINE OF SHRA/TSRA OUT THERE THIS AFTN...POSSIBLY MAKING IT ESE TOWARD SE TX LATE EVNG & OVERNIGHT. WILL SEE HOW THIS ALL PLAYS OUT, BUT WENT AHEAD AND THREW THE POTENTIAL OF THIS OCCURRING IN THE 9-2AM TIMEFRAME IN THE CLL, UTS, CXO TAFS. CONSIDERABLE UNCERTAINTY IN THIS ATTM BUT FEEL IT`S ENOUGH TO BEGIN MENTIONING. 47 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 63 85 56 75 54 / 40 20 10 10 20 HOUSTON (IAH) 64 85 61 78 57 / 30 20 20 10 10 GALVESTON (GLS) 69 81 66 77 66 / 30 20 20 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...40 AVIATION/MARINE...47
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
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 86 72 77 / 20 20 30 40 BROWNSVILLE 71 87 72 78 / 20 40 30 50 HARLINGEN 71 90 71 80 / 20 40 40 50 MCALLEN 70 92 72 80 / 20 30 30 50 RIO GRANDE CITY 68 94 71 80 / 20 20 30 40 SOUTH PADRE ISLAND 72 79 72 76 / 20 20 30 40 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 67/59
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
227 PM CDT Sat Apr 18 2015 .UPDATE... The Storm Prediction Center has just issued Severe Thunderstorm Watch number 72, and it covers all of West Central Texas. So, we just sent an update to our Zone forecast to include a watch headline for all of our counties. && .PREV DISCUSSION... /ISSUED 1249 PM CDT Sat Apr 18 2015/ AVIATION... /18Z TAFS/ Expect VFR conditions to dominate for the next 24 hours and thunderstorms this afternoon and evening. Thunderstorms will likely impact Sonora, Brady, and Junction this afternoon and evening. PREV DISCUSSION... /ISSUED 631 AM CDT Sat Apr 18 2015/ AVIATION... /12Z TAFS/ Two upper level disturbance will bring a round of storms to most TAF sites this morning and again this afternoon. Latest radar data is showing an area of storms moving east and northeast towards KSOA and KJCT and could reach those sites between 12Z and 15Z. Main impacts will be gusty winds, brief heavy rain, lightning and low visibilities. The IFR Cigs should gradually improve to VFR shortly after 15Z. The next round of storms may form along the dryline after 18Z at KSOA, KBBD and KJCT. A few of these may become severe and produce large hail, damaging winds and very heavy rainfall. PREV DISCUSSION... /ISSUED 420 AM CDT Sat Apr 18 2015/ SHORT TERM... (Today and Tonight) There is a threat for severe thunderstorms across the eastern half of West Central Texas today as an upper level trough associated with the upper low near the Four Corners moves across the region. The main threats will be large hail and damaging winds. SPC has placed much of the area east of the dryline in a slight risk for severe thunderstorms today. Latest radar is showing showers developing across the mountains in northern Mexico, south of Sanderson, in association with the next approaching shortwave as can be seen on water vapor satellite imagery. This could bring a round of showers and thunderstorms to West Central Texas this morning before the main upper trough moves across later this afternoon. The dryline is forecast to move east today as the RUC model progs this front from Haskell to just east of San Angelo to Sonora by early evening. This dryline should trigger scattered thunderstorms this afternoon as the following ingredients come together: dewpoints ranging from the upper 50s to the lower 60s, moderate 0-6km shear, MU CAPE Values 1500-2000 J/KG, a weak capping inversion, approaching upper trough and a right rear entrance region of the southern stream upper level jet flowing across the area. These parameters should set the stage for the development of a few supercells today, resulting in large hail and damaging winds. These storms may continue into the early evening hours before dissipating. Highest Pops were placed across the Northwest Hill Country extending north to Brownwood. Went closer to the warmer MAV MOS for temps as the dry warm air invades the western part of the region today. 26 LONG TERM... (Sunday through Friday) Cold front will move through Sunday. Dry southwest to west winds ahead of the front will not only preclude rain chances, but also give a boost to temperatures, being downslope compression. Still, cold advection will bring cooler temperatures Sunday, with highs in the 70s. Isolated dryline thunderstorms possible mid and late week. West Central Texas will be under a broad upper ridge, so widespread showers or thunderstorms not expected. Could see a few highs approach 90s, especially Wednesday and Thursday. && .PRELIMINARY POINT TEMPS/POPS... Abilene 54 77 46 72 51 / 20 5 5 5 5 San Angelo 54 82 48 74 53 / 10 5 5 5 10 Junction 55 85 50 74 54 / 30 5 5 5 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
223 PM CDT SAT APR 18 2015 .UPDATE... TO ISSUE SEVERE THUNDERSTORM WATCH 72. THUNDERSTORMS ARE BEGINNING TO FORM ALONG THE DRYLINE AND ARE EXPECTED TO MOVE TO THE SOUTHEAST AND INTO OUR CWA. CONDITIONS REMAIN FAVORALE FOR STORMS TO BECOME SEVERE. WE HAVE ISSUED A SEVERE THUNDERSTOMR WATCH FOR THE AREA FROM BURNET TO BANDERA TO VAL VERDE COUNTIES AND NORTHWARD. && .PREV DISCUSSION... /ISSUED 1256 PM CDT SAT APR 18 2015/ AVIATION... ISOLD SHRA/TSRA ARE POSSIBLE EARLY THIS AFTERNOON. SHRA/TSRA WILL DEVELOP ALONG THE DRYLINE THIS AFTERNOON NEAR THE EDWARDS PLATEAU AND MOVE ACROSS THE HILL COUNTRY AND I-35 CORRIDOR AREAS LATE THIS AFTERNOON INTO THIS EVENING. BEST CHANCES WILL BE AT KAUS/KSAT WHERE HAVE GONE WITH TEMPO FROM 19/00Z TO 19/04Z. KSSF SHOULD BE JUST SOUTH OF THE LINE WHILE SHRA/TSRA WILL DISSIPATE WHEN THEY DRIFT OF THE SERRANIAS DEL BURRO WITH NO IMPACT TO KDRT. AREAS OF MVFR CIGS WILL LIFT TO VFR SCT-BKN SKIES BY MID AFTERNOON. MVFR CIGS WILL REDEVELOP OVERNIGHT. DRIER AIR WILL FILTER IN FROM THE WEST ON SUNDAY WITH A RETURN TO VFR SKIES BY MIDDAY. NELY WINDS LESS THAN 7 KTS WILL TURN TO SELY THIS AFTERNOON AND THEN SLY TONIGHT AND THEN WLY ON SUNDAY. WIND GUSTS TO 50 KTS ARE POSSIBLE IN AND NEAR TSRA. PREV DISCUSSION... /ISSUED 1201 PM CDT SAT APR 18 2015/ UPDATE... CONVECTION HAS BEEN A LITTLE SLOWER TO BEGIN THIS MORNING. HAVE REDUCED POPS FOR THE NEXT COUPLE OF HOURS...ESPECIALLY ACROSS THE EASTERN HALF OF THE CWA. SPC HAS UPDATED THE DAY ONE OUTLOOK AND INCREASED OUR RISK TO ENHANCED. EXPECTING STRONG TO SEVERE STORMS TO FORM LATER THIS AFTERNOON ALONG THE DRYLINE WHICH CURRENTLY STRETCHES FROM AROUND CHILDRESS TO MIDLAND TO THE BIG BEND. THESE STORMS WILL MOVE EASTWARD AND INTO OUR NORTHERN AREA LATE THIS AFTERNOON OR EARLY EVENING. THE MAIN THREAT LOOKS TO BE LARGE HAIL AND DAMAGING WINDS. THERE IS ALSO A LESSER THREAT FOR TORNADOES. WITH ALL OF THE RAIN OVER THE PAST COUPLE OF DAYS LOCALLY HEAVY RAINFALL IN STORMS WILL RUNOFF QUICKLY AND MAY CAUSE FLASH FLOODING...BUT THIS IS NOT A WIDESPREAD THREAT. PREV DISCUSSION... /ISSUED 611 AM CDT SAT APR 18 2015/ AVIATION... CEILINGS ARE IFR/MVFR AROUND THE AREA AIRPORTS THIS MORNING AND CONDITIONS SHOULD SLOWLY IMPROVE TO VFR BY EARLY AFTERNOON. CONVECTION HAS DEVELOPED WEST OF KDRT AND WILL SHOW VCTS FOR THE FIRST FEW HOURS OF THE VALID TAF PERIOD. CONFIDENCE REGARDING CONVECTION CHANCES THIS AFTERNOON IS NOT VERY HIGH. THE MOST LIKELY SCENARIO IS FOR THIS ELEVATED CONVECTION TO MOVE EAST THIS MORNING AND THE ATMOSPHERE TO REENERGIZE BY THE LATE AFTERNOON HOURS. THERE SHOULD BE A SURFACE CONVERGENCE ZONE DEVELOPING WEST OF THE I-35 TAF SITES. THE MOST LIKELY TIME THESE WOULD BE TO THE TERMINALS WOULD BE AROUND 22-03Z. WILL HANDLE THIS WITH A VCTS FOR NOW. ADDITIONAL MVFR RESTRICTIONS ARE POSSIBLE TONIGHT...BUT IFR IS NOT ANTICIPATED AS SLIGHTLY DRIER AIR MOVES INTO THE AREA. HAMPSHIRE PREV DISCUSSION... /ISSUED 401 AM CDT SAT APR 18 2015/ SHORT TERM (TODAY THROUGH SUNDAY)... AN UPPER LEVEL STORM SYSTEM IS CENTERED ACROSS COLORADO EARLY THIS MORNING. THIS SYSTEM IS FORECAST TO MOVE TO THE NORTHEAST AND THEN EAST THROUGH THE WEEKEND AND BECOMES AN OPEN WAVE LATE SUNDAY AFTERNOON. SEVERAL SHORT WAVES ASSOCIATED WITH THE UPPER LEVEL LOW ARE ANTICIPATED TO PUSH ACROSS THE AREA FOR THE NEXT 12 TO 18 HOURS AND ENHANCE STORM DEVELOPMENT LATE THIS MORNING THROUGH THE EVENING HOURS. AT LOWER LEVELS...A PRE-FRONTAL TROUGH/DRY-LINE WILL SERVE AS THE MAIN FOCUS AS STORMS FORM IN THE MOIST AND WARM SECTOR. BY THIS AFTERNOON...DEWPOINT TEMPERATURES ARE FORECAST TO REACH THE MID TO UPPER 60S WITH AREA SOUNDINGS SUGGESTING ML CAPES OF 1500 TO 2500J/KG AND LI RANGING FROM -5 TO -10 FOR LARGE TO EXTREME INSTABILITY. THEREFORE...ANY STORM THAT DOES DEVELOP HAS THE POTENTIAL TO BECOME STRONG OR SEVERE. PER SPC DAY 1 CONVECTIVE OUTLOOK...ALL OF SOUTH CENTRAL TEXAS WITH THE EXCEPTION OF THE NORTHWEST PORTION OF VAL VERDE COUNTY...IS UNDER A SLIGHT RISK OF SEVERE THUNDERSTORMS. HIRES SOLUTIONS ARE HAVING DIFFICULTIES ON TIMING AND AREAS OF STORM DEVELOPMENT INITIALLY. THE HRRR STARTS CONVECTION ACROSS THE SOUTHERN COUNTIES AS AN MCS DEVELOPS ACROSS THE COASTAL PLAINS AND MOVE TO THE EAST. THE TEXAS TECH IS MORE AGGRESSIVE ON FORMING STORMS AHEAD OF THE DRY-LINE AS IT PUSHES TO THE EAST AND OVER THE EDWARDS PLATEAU/HILL COUNTRY AREA. THE HRRR DOES DEVELOP CONVECTION AHEAD OF THE DRY-LINE THIS AFTERNOON BUT NOWHERE NEAR TEXAS TECH MODEL. THEREFORE...THE SHORT-TERM/FIRST PERIOD CONSISTS ON A BLEND OF THE HRRR/TEXAS TECH SOLUTIONS. BY LATER THIS EVENING...MID LEVEL WESTERLY WILL TAKE OVER AS THE UPPER LEVEL LOW PUSHES TO THE EAST...MARKING THE END OF RAIN CHANCES THROUGH MONDAY. WITH A WESTERLY FLOW IN PLACE FOR SUNDAY...EXPECT A NICE WARMUP WITH HIGHS IN THE UPPER 80S AND LOWER 90S. CAN NOT RULE OUT AN ISOLATED STORM ACROSS THE FAR EASTERN COUNTIES SUNDAY AFTERNOON AS LINGERING INSTABILITY REMAINS. A BACK DOOR COLD FRONT WILL PUSH ACROSS THE AREA SUNDAY EVENING TO COOL THE OVERNIGHT TEMPS INTO THE 50S AREAWIDE. LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)... A CLEAR NIGHT IS IN STORE FOR SUNDAY NIGHT WITH NORTHERLY WINDS AND COOL TEMPERATURES FOLLOWED BY A PARTLY CLOUDY DAY ON MONDAY. SOUTHERLY FLOW RETURNS TUESDAY AS WELL AS THE RAIN CHANCES FOR SOUTH CENTRAL TEXAS. SEVERAL SHORT WAVES ARE EXPECTED TO PASS BY AND TRIGGER SHOWERS AND STORMS THROUGH FRIDAY. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 61 89 57 76 57 / 40 - - 0 20 AUSTIN BERGSTROM INTL AIRPORT 60 87 55 76 56 / 40 - - 0 20 NEW BRAUNFELS MUNI AIRPORT 60 87 56 76 56 / 30 0 10 - 20 BURNET MUNI AIRPORT 57 87 53 74 54 / 40 0 0 0 20 DEL RIO INTL AIRPORT 59 90 59 79 61 / 20 0 - 10 20 GEORGETOWN MUNI AIRPORT 59 87 54 74 54 / 40 - - 0 20 HONDO MUNI AIRPORT 59 88 57 78 58 / 20 0 - - 30 SAN MARCOS MUNI AIRPORT 61 86 56 75 56 / 40 0 10 - 20 LA GRANGE - FAYETTE REGIONAL 63 86 57 75 58 / 40 10 10 - 20 SAN ANTONIO INTL AIRPORT 61 88 58 77 59 / 30 0 - - 30 STINSON MUNI AIRPORT 61 88 59 77 59 / 20 0 10 - 30 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...04 SYNOPTIC/GRIDS...05 PUBLIC SERVICE/DATA COLLECTION...01
AREA FORECAST DISCUSSION
NWS AMARILLO TX
221 PM CDT SAT APR 18 2015 .DISCUSSION... EARLY THIS AFTERNOON A DEEP CLOSED LOW WAS SITUATED OVER EASTERN COLORADO AND SLOWLY MOVING EAST. A BAND OF CLOUDS ASSOCIATED WITH A RELATIVELY POTENT VORT LOBE ROTATING AROUND THE MID-UPPER LOW WAS EVIDENT IN IR/VIS SATELLITE. SURFACE OBSERVATIONS SHOW LIGHT RAIN BENEATH THIS BAND OF CLOUDS AT CLAYTON NEW MEXICO AND PRESUMABLY FURTHER SOUTH-SOUTHWEST EAST OF TUCUMCARI INTO THE FAR WESTERN TEXAS PANHANDLE WHERE LIGHT ECHOS WERE PRESENT ON REGIONAL RADAR MOSAIC. FURTHER EAST ACROSS THE TEXAS AND OKLAHOMA PANHANDLE LOW CLOUDS HAVE DIMINISHED AND/OR SHIFTED INTO OKLAHOMA AS SURFACE WINDS CONTINUE TO VEER SLIGHTLY. SHALLOW LOW LEVEL MOISTURE SEEN ON 12Z KAMA SOUNDING REMAINS ACROSS THE EASTERN PANHANDLES EAST OF A DIFFUSE DRYLINE. THERE REMAINS SOME UNCERTAINTY ON THE POSITION OF THE DRYLINE THAT IS EXPECTED TO SHARPEN THIS AFTERNOON AS DIABATIC HEATING/MIXING COMMENCES. USING SHORT RANGE MODEL FORECAST SOUNDINGS AS GUIDANCE ON THE DEPTH OF MOISTURE OFF THE CAPROCK AND ESPECIALLY FURTHER EAST NEAR THE OKLAHOMA BORDER LEADS TO FAIRLY HIGH CONFIDENCE ON THE PREVIOUS FORECAST WHICH RELEGATES ANY SUBSTANTIAL DEEP CONVECTION TO NEAR OR JUST EAST OF THE OKLAHOMA STATE LINE LATER THIS AFTERNOON. LOW LEVEL MOISTURE IS DEEPER FROM THERE EASTWARD INTO OKLAHOMA AND THUS DRYLINE CIRCULATION THAT DEVELOPS STANDS A BETTER CHANCE AT INITIATING CONVECTION THERE THAN WAS THE CASE FURTHER WEST YESTERDAY. SO THROUGH THE LATE AFTERNOON AND EVENING THERE IS ONLY A LOW PROBABILITY OF ISOLATED-SCATTERED CONVECTION ACROSS THE EXTREME EASTERN PORTION OF THE PANHANDLES WITH BETTER CHANCES OUT OF THE FORECAST AREA ACROSS WESTERN OKLAHOMA. IF THE ABOVE ASSESSMENT IS MISPLACED SLIGHTLY EAST THAN ANY STORM THAT DOES DEVELOP ON OUR SIDE OF THE STATE LINE WOULD HAVE THE POTENTIAL TO BECOME SEVERE DUE TO MODERATE INSTABILITY AND SUFFICIENT DEEP LAYER SHEAR OF AROUND 30 KNOTS FOR STORM ORGANIZATION/PERSISTENCE. LARGE HAIL WOULD BE THE PRIMARY THREAT INTO THE EVENING GIVEN STEEP MID LEVEL LAPSE RATES OWING TO THE APPROACHING MID-UPPER LOW. WILL CONTINUE TO MONITOR TRENDS IN SURFACE OBSERVATIONS AND DRYLINE EVOLUTION THROUGHOUT THE AFTERNOON. FURTHER WEST OF THE DRYLINE...DEEP MIXING WILL OCCUR GENERALLY EAST OF THE AFOREMENTIONED BAND OF LOW-MID CLOUDS NOW ENTERING THE TEXAS PANHANDLE. CU FIELD IS INCREASING IMMEDIATELY AHEAD OF THIS. BASES SHOULD BECOME RELATIVELY HIGH AS MIXED LAYER DEEPENS THROUGH THE AFTERNOON. WITH FORCING FROM PREVIOUSLY MENTIONED VORT LOBE CONVECTION MAY BECOME DEEP ENOUGH FOR SHOWERS AND THUNDERSTORMS FOR MUCH OF THE AREA LATER THIS AFTERNOON. IF CONVECTION BECOMES DEEP ENOUGH FOR CHARGE SEPARATION AND LIGHTNING...LIMITED INSTABILITY SHOULD PRECLUDE THE THREAT OF SEVERE THUNDERSTORMS. PROGNOSTICATIONS FROM THE HI-RES CONVECTION ALLOWING GUIDANCE INCLUDING THE HRRR AND TTU WRF SEEM TO LINE UP WELL WITH THE ABOVE THINKING. AS THE MID-UPPER LOW CONTINUES TO SHIFT EAST A COLD FRONT WILL MOVE THROUGH THE AREA TONIGHT. MODEL GUIDANCE IS IN AGREEMENT IN AN EVOLUTION OF THE LOW INTO A MORE OPEN AND PROGRESSIVE WAVE THAT WILL BE EAST OF THE AREA BY TOMORROW AFTERNOON. AN AREA OF MOISTURE ON THE BACK SIDE OF THIS EVOLVING SHORTWAVE TROUGH FAVORABLY TIMED WITH PEAK HEATING SHOULD BE ENOUGH FOR EXTENSIVE CUMULUS DEVELOPMENT DURING THE AFTERNOON POSSIBLY ENOUGH FOR BROKEN SKY CONDITIONS ESPECIALLY ACROSS THE EASTERN PORTION OF THE AREA. DEPTH OF CONVECTION IN ROUGHLY THE NORTHEAST THIRD WILL NEED TO BE MONITORED AS IT MAY BECOME SUFFICIENT FOR A FEW SHOWERS GIVEN RESIDUAL COOL MID LEVEL TEMPERATURES AND RELATIVELY HIGH TQ INDEX VALUES. ADJUSTED LOW POPS ON SUNDAY AFTERNOON TO EXTEND A BIT FURTHER SOUTH AND WEST TO ACCOUNT FOR THIS. EARLY NEXT WEEK A SPLIT UPPER FLOW PATTERN WILL EXIST WITH STRONG PERIODICALLY PERTURBED WESTERLY SOUTHERN BRANCH JUST SOUTH OF US AND NORTHWESTERLY NORTHERN BRANCH ACROSS THE CENTRAL PLAINS. MEAN RIDGING WILL BE PRESENT OVER THE WESTERN STATES. GRADUALLY INCREASING 500 MB HEIGHTS AND A SLIGHTLY MORE AMPLIFIED PATTERN WILL EVOLVE THROUGH THE WEEK ESPECIALLY AS ANOTHER CLOSED LOW DEVELOPS AND DEEPENS OVER THE SOUTHWESTERN CONUS BY THURSDAY. AS THIS MOVES EAST THIS WILL PROBABLY RESULT IN ANOTHER CONVECTIVELY ACTIVE PATTERN FOR THE LATTER HALF OF THE WEEK. AS IS TYPICALLY THE CASE AT THAT TIME RANGE MODEL GUIDANCE DIFFERS IN TIMING AND AMPLITUDE BUT THE SIGNAL IS THERE FOR A SCENARIO FAVORING A NORTH/WEST SURGE OF LOW LEVEL MOISTURE AND FORCING FOR ASCENT RESULTING IN ABOVE CLIMO PRECIPITATION PROBABILITIES AND THE POSSIBILITY OF SEVERE THUNDERSTORMS BY MID AND ESPECIALLY LATE WEEK. EVEN BEFORE THEN THERE WILL BE A FEW OPPORTUNITIES FOR PRECIPITATION EARLIER IN THE WEEK AS DIFFICULT TO RESOLVE SMALL SHORTWAVE TROUGHS WITHIN MEAN WEST-NORTHWESTERLY FLOW CROSS THE AREA. CONVECTION MAY EMANATE FROM THE HIGHER TERRAIN OF COLORADO AND NEW MEXICO AND MOVE INTO THE PANHANDLES LATE MONDAY AND AGAIN LATE TUESDAY...ALTHOUGH THIS FORECAST WILL BE LESS DETERMINISTIC WITH TIMING OF HIGHER PROBABILITIES OF PRECIPITATION AND MORE BROAD BRUSH GIVEN INHERENT UNCERTAINTIES OF THIS TYPE PATTERN. BRB && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 05/17
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1256 PM CDT SAT APR 18 2015 .AVIATION... ISOLD SHRA/TSRA ARE POSSIBLE EARLY THIS AFTERNOON. SHRA/TSRA WILL DEVELOP ALONG THE DRYLINE THIS AFTERNOON NEAR THE EDWARDS PLATEAU AND MOVE ACROSS THE HILL COUNTRY AND I-35 CORRIDOR AREAS LATE THIS AFTERNOON INTO THIS EVENING. BEST CHANCES WILL BE AT KAUS/KSAT WHERE HAVE GONE WITH TEMPO FROM 19/00Z TO 19/04Z. KSSF SHOULD BE JUST SOUTH OF THE LINE WHILE SHRA/TSRA WILL DISSIPATE WHEN THEY DRIFT OF THE SERRANIAS DEL BURRO WITH NO IMPACT TO KDRT. AREAS OF MVFR CIGS WILL LIFT TO VFR SCT-BKN SKIES BY MID AFTERNOON. MVFR CIGS WILL REDEVELOP OVERNIGHT. DRIER AIR WILL FILTER IN FROM THE WEST ON SUNDAY WITH A RETURN TO VFR SKIES BY MIDDAY. NELY WINDS LESS THAN 7 KTS WILL TURN TO SELY THIS AFTERNOON AND THEN SLY TONIGHT AND THEN WLY ON SUNDAY. WIND GUSTS TO 50 KTS ARE POSSIBLE IN AND NEAR TSRA. && .PREV DISCUSSION... /ISSUED 1201 PM CDT SAT APR 18 2015/ UPDATE... CONVECTION HAS BEEN A LITTLE SLOWER TO BEGIN THIS MORNING. HAVE REDUCED POPS FOR THE NEXT COUPLE OF HOURS...ESPECIALLY ACROSS THE EASTERN HALF OF THE CWA. SPC HAS UPDATED THE DAY ONE OUTLOOK AND INCREASED OUR RISK TO ENHANCED. EXPECTING STRONG TO SEVERE STORMS TO FORM LATER THIS AFTERNOON ALONG THE DRYLINE WHICH CURRENTLY STRETCHES FROM AROUND CHILDRESS TO MIDLAND TO THE BIG BEND. THESE STORMS WILL MOVE EASTWARD AND INTO OUR NORTHERN AREA LATE THIS AFTERNOON OR EARLY EVENING. THE MAIN THREAT LOOKS TO BE LARGE HAIL AND DAMAGING WINDS. THERE IS ALSO A LESSER THREAT FOR TORNADOES. WITH ALL OF THE RAIN OVER THE PAST COUPLE OF DAYS LOCALLY HEAVY RAINFALL IN STORMS WILL RUNOFF QUICKLY AND MAY CAUSE FLASH FLOODING...BUT THIS IS NOT A WIDESPREAD THREAT. PREV DISCUSSION... /ISSUED 611 AM CDT SAT APR 18 2015/ AVIATION... CEILINGS ARE IFR/MVFR AROUND THE AREA AIRPORTS THIS MORNING AND CONDITIONS SHOULD SLOWLY IMPROVE TO VFR BY EARLY AFTERNOON. CONVECTION HAS DEVELOPED WEST OF KDRT AND WILL SHOW VCTS FOR THE FIRST FEW HOURS OF THE VALID TAF PERIOD. CONFIDENCE REGARDING CONVECTION CHANCES THIS AFTERNOON IS NOT VERY HIGH. THE MOST LIKELY SCENARIO IS FOR THIS ELEVATED CONVECTION TO MOVE EAST THIS MORNING AND THE ATMOSPHERE TO REENERGIZE BY THE LATE AFTERNOON HOURS. THERE SHOULD BE A SURFACE CONVERGENCE ZONE DEVELOPING WEST OF THE I-35 TAF SITES. THE MOST LIKELY TIME THESE WOULD BE TO THE TERMINALS WOULD BE AROUND 22-03Z. WILL HANDLE THIS WITH A VCTS FOR NOW. ADDITIONAL MVFR RESTRICTIONS ARE POSSIBLE TONIGHT...BUT IFR IS NOT ANTICIPATED AS SLIGHTLY DRIER AIR MOVES INTO THE AREA. HAMPSHIRE PREV DISCUSSION... /ISSUED 401 AM CDT SAT APR 18 2015/ SHORT TERM (TODAY THROUGH SUNDAY)... AN UPPER LEVEL STORM SYSTEM IS CENTERED ACROSS COLORADO EARLY THIS MORNING. THIS SYSTEM IS FORECAST TO MOVE TO THE NORTHEAST AND THEN EAST THROUGH THE WEEKEND AND BECOMES AN OPEN WAVE LATE SUNDAY AFTERNOON. SEVERAL SHORT WAVES ASSOCIATED WITH THE UPPER LEVEL LOW ARE ANTICIPATED TO PUSH ACROSS THE AREA FOR THE NEXT 12 TO 18 HOURS AND ENHANCE STORM DEVELOPMENT LATE THIS MORNING THROUGH THE EVENING HOURS. AT LOWER LEVELS...A PRE-FRONTAL TROUGH/DRY-LINE WILL SERVE AS THE MAIN FOCUS AS STORMS FORM IN THE MOIST AND WARM SECTOR. BY THIS AFTERNOON...DEWPOINT TEMPERATURES ARE FORECAST TO REACH THE MID TO UPPER 60S WITH AREA SOUNDINGS SUGGESTING ML CAPES OF 1500 TO 2500J/KG AND LI RANGING FROM -5 TO -10 FOR LARGE TO EXTREME INSTABILITY. THEREFORE...ANY STORM THAT DOES DEVELOP HAS THE POTENTIAL TO BECOME STRONG OR SEVERE. PER SPC DAY 1 CONVECTIVE OUTLOOK...ALL OF SOUTH CENTRAL TEXAS WITH THE EXCEPTION OF THE NORTHWEST PORTION OF VAL VERDE COUNTY...IS UNDER A SLIGHT RISK OF SEVERE THUNDERSTORMS. HIRES SOLUTIONS ARE HAVING DIFFICULTIES ON TIMING AND AREAS OF STORM DEVELOPMENT INITIALLY. THE HRRR STARTS CONVECTION ACROSS THE SOUTHERN COUNTIES AS AN MCS DEVELOPS ACROSS THE COASTAL PLAINS AND MOVE TO THE EAST. THE TEXAS TECH IS MORE AGGRESSIVE ON FORMING STORMS AHEAD OF THE DRY-LINE AS IT PUSHES TO THE EAST AND OVER THE EDWARDS PLATEAU/HILL COUNTRY AREA. THE HRRR DOES DEVELOP CONVECTION AHEAD OF THE DRY-LINE THIS AFTERNOON BUT NOWHERE NEAR TEXAS TECH MODEL. THEREFORE...THE SHORT-TERM/FIRST PERIOD CONSISTS ON A BLEND OF THE HRRR/TEXAS TECH SOLUTIONS. BY LATER THIS EVENING...MID LEVEL WESTERLY WILL TAKE OVER AS THE UPPER LEVEL LOW PUSHES TO THE EAST...MARKING THE END OF RAIN CHANCES THROUGH MONDAY. WITH A WESTERLY FLOW IN PLACE FOR SUNDAY...EXPECT A NICE WARMUP WITH HIGHS IN THE UPPER 80S AND LOWER 90S. CAN NOT RULE OUT AN ISOLATED STORM ACROSS THE FAR EASTERN COUNTIES SUNDAY AFTERNOON AS LINGERING INSTABILITY REMAINS. A BACK DOOR COLD FRONT WILL PUSH ACROSS THE AREA SUNDAY EVENING TO COOL THE OVERNIGHT TEMPS INTO THE 50S AREAWIDE. LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)... A CLEAR NIGHT IS IN STORE FOR SUNDAY NIGHT WITH NORTHERLY WINDS AND COOL TEMPERATURES FOLLOWED BY A PARTLY CLOUDY DAY ON MONDAY. SOUTHERLY FLOW RETURNS TUESDAY AS WELL AS THE RAIN CHANCES FOR SOUTH CENTRAL TEXAS. SEVERAL SHORT WAVES ARE EXPECTED TO PASS BY AND TRIGGER SHOWERS AND STORMS THROUGH FRIDAY. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 81 61 89 57 76 / 40 40 - - - AUSTIN BERGSTROM INTL AIRPORT 81 60 87 55 76 / 50 40 - - - NEW BRAUNFELS MUNI AIRPORT 81 60 87 56 76 / 50 30 0 - - BURNET MUNI AIRPORT 79 57 87 53 74 / 40 40 - - - DEL RIO INTL AIRPORT 86 59 90 59 79 / 30 10 0 - 10 GEORGETOWN MUNI AIRPORT 79 59 87 54 74 / 40 40 10 - - HONDO MUNI AIRPORT 82 59 88 57 78 / 40 20 0 - - SAN MARCOS MUNI AIRPORT 81 61 86 56 75 / 50 40 0 - - LA GRANGE - FAYETTE REGIONAL 80 63 86 57 75 / 50 40 20 10 10 SAN ANTONIO INTL AIRPORT 81 61 88 58 77 / 40 30 0 - - STINSON MUNI AIRPORT 82 61 88 59 77 / 40 20 - - - && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...04 SYNOPTIC/GRIDS...05 PUBLIC SERVICE/DATA COLLECTION...01
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1249 PM CDT SAT APR 18 2015 .AVIATION... THE UPPER LOW NOW SPINNING OVER COLORADO WILL MOVE EAST ACROSS THE PLAINS OVER THE NEXT 24 HOURS. A SHORTWAVE TROUGH WORKING ITS WAY AROUND THE SOUTH SIDE OF THE UPPER LOW WILL MOVE ACROSS CENTRAL TEXAS THIS AFTERNOON...AIDING IN THE DEVELOPMENT OF SCATTERED SHOWERS AND THUNDERSTORMS WEST OF THE TAF LOCATIONS LATE THIS AFTERNOON. CONVECTION WILL SPREAD EAST ACROSS NORTH TEXAS THIS EVENING. TIMING WILL BE A CHALLENGE...BUT THE LATEST HI-RES GUIDANCE ONCE AGAIN PINPOINTS THE 00-04Z TIME FRAME AS THE MOST LIKELY AT ALL TAF LOCATIONS THIS EVENING. CONVECTION SHOULD MOVE EAST OF THE AREA AND WEAKEN AROUND MIDNIGHT LOCAL. A COLD FRONT WILL PUSH SOUTHEAST ACROSS NORTH TEXAS TOMORROW. SOUTH TO SOUTHWEST WINDS WILL INCREASE TO 10-15 KT AROUND SUNRISE AHEAD OF THE FRONT. WINDS WILL VEER TO THE WEST SHORTLY AFTER 18Z WHILE INCREASING TO 15-20 KT. NORTHWEST WINDS ARE EXPECTED AT ALL LOCATIONS BY 00Z SUNDAY EVENING. AT THIS TIME...IT APPEARS THAT ANY CONVECTION ASSOCIATED WITH THE FRONT WILL REMAIN EAST OF ALL TAF SITES. 30 && .UPDATE... MORNING UPPER AIR DATA AND SHORT-TERM MODEL GUIDANCE HAS IDENTIFIED A SHORTWAVE TROUGH THAT IS PIVOTING AROUND THE UPPER LOW OVER COLORADO. THIS SHORTWAVE WILL TRACK THROUGH TEXAS THIS AFTERNOON AND EVENING. A DRY LINE IS FORECAST TO SET UP JUST WEST OF THE CWA BORDER THIS AFTERNOON AND WILL BECOME THE FOCUS FOR SCATTERED CONVECTION WHEN FORCING FROM THE SHORTWAVE TROUGH ARRIVES. CONVECTIVE INITIATION SHOULD START AFTER 3 PM JUST WEST OF THE CWA...WITH THESE STORMS MOVING/DEVELOPING GRADUALLY NORTHEASTWARD INTO AND THROUGH THE CWA DURING THE LATE AFTERNOON AND EVENING HOURS. GIVEN THE EXPECTED TIMING...HAVE LOWERED THE POPS ALONG AND EAST OF I-35 FOR THE TODAY PERIOD AS ANY RAIN/STORMS SHOULD HOLD OFF UNTIL THIS EVENING FOR THESE AREAS. THERE IS A LACK OF LOW LEVEL WIND FLOW EVIDENT IN THE MORNING DATA AND THE AIRMASS HAS BEEN FAIRLY WORKED OVER BY THE CONVECTION FROM YESTERDAY AND LAST NIGHT. HOWEVER THE APPROACH OF THE SHORTWAVE TROUGH WILL HELP TURN WINDS TO THE SOUTH BY THE AFTERNOON...THEREBY INCREASING MOISTURE/THETA-E ADVECTION AND BULK SHEAR VALUES ACROSS NORTH TEXAS. TEMPERATURES WILL ALSO WARM INTO THE UPPER 70S AND LOWER 80S OVER NORTH TEXAS TODAY...WHICH WILL YIELD GENERALLY 1000-2000 J/KG OF SURFACE BASED CAPE. THUS THE AIRMASS SHOULD BE RECHARGED JUST ENOUGH TO SUPPORT SCATTERED CONVECTION WITH A POTENTIAL FOR SEVERE WIND AND HAIL...ESPECIALLY WEST OF I-35 IN THE LATE AFTERNOON HOURS. THE SEVERE THREAT WILL DIMINISH AS THE STORMS HEAD EAST OF I-35 DUE TO THE LOSS OF HEATING AND INCREASING CINH. TR.92 && .PREV DISCUSSION... /ISSUED 415 AM CDT SAT APR 18 2015/ THE UPPER LOW THAT HAS BEEN PARKED OVER THE FOUR CORNERS IS BEGINNING TO DISLODGE...AND BY THIS TIME SUNDAY MORNING IT WILL BE OVER THE HIGH PLAINS NEAR THE COLORADO/KANSAS BORDER. THIS WILL STEADILY VEER THE 700MB FLOW ACROSS WEST TEXAS TODAY...HELPING TO NUDGE THE DRYLINE FARTHER EAST THAN IN RECENT DAYS. ALTHOUGH WITHIN THE FIRST 24 HOURS OF THE LATEST GUIDANCE...OPERATIONAL SOLUTIONS VARY WIDELY ON THE LATE AFTERNOON POSITION. ALTHOUGH THE NAM IS AMONG THE FARTHEST WEST...WHICH IS UNUSUAL IN THIS SCENARIO...THE CONSENSUS AMONG THE MESOSCALE GUIDANCE IS FOR THE BOUNDARY TO REACH A VERNON-SAN ANGELO LINE NEAR PEAK HEATING. OUR FORECAST WILL FAVOR THIS POSITION. BASED ON THE MID-LEVEL FLOW... THERE SHOULD BE A BULGE NEAR THE RED RIVER. THE RAP AND TTU WRF SHOW THIS CLEARLY...ADDING TO THE CONFIDENCE IN THEIR EVOLUTION OF THE BOUNDARY TODAY. THE ATMOSPHERE ACROSS NORTH TEXAS HAS BEEN WELL WORKED OVER. THIS STABILITY...COUPLED WITH SUBSIDENCE IN THE WAKE OF A DEPARTING DISTURBANCE...SHOULD PRECLUDE MUCH ADDITIONAL PRECIPITATION THIS MORNING. WEAK LOW-LEVEL FLOW WILL RESULT IN NEGLIGIBLE MOIST ADVECTION TODAY...AND DESTABILIZATION THIS AFTERNOON WILL BE PRIMARILY GOVERNED BY SURFACE HEATING. ALTHOUGH THE I-35 CORRIDOR WILL BE SLOW TO CLEAR TODAY...WESTERN NORTH TEXAS WILL SEE SUFFICIENT SUNSHINE. EXPECT THUNDERSTORMS TO DEVELOP ALONG THE DRYLINE MID TO LATE AFTERNOON. THOUGH RELATIVELY WEAK...THE STEERING FLOW ALOFT SHOULD GUIDE THE ACTIVITY EAST THROUGH NORTH TEXAS THIS EVENING. EVEN THOUGH THE SURFACE LAYER WILL BE STEADILY STABILIZING AT THAT TIME...THE COLD POOL ASSOCIATED WITH AN ORGANIZED MCS SHOULD PROLONG THE LIFESPAN OF ITS UPDRAFTS. THIS WILL MAINTAIN A HAIL THREAT WELL INTO THE EVENING. THIS IS NOT THE TYPICAL SETUP FOR A SQUALL LINE...BUT A WELL ORGANIZED COMPLEX COULD POSE A WIND THREAT AS WELL. THE SPEED SHOULD BE SUFFICIENT TO AVOID SIGNIFICANT FLOODING CONCERNS IN MOST AREAS...BUT WHERE HEAVY RAIN HAS FALLEN RECENTLY...ADDITIONAL RAINFALL COULD REAGGRAVATE FLOODING ISSUES. AS THE UPPER LOW EJECTS THROUGH THE CENTRAL PLAINS...IT WILL SURGE A COLD FRONT THROUGH THE REGION. WITH WIDESPREAD ACTIVITY THIS EVENING...LARGE-SCALE SUBSIDENCE INVADING...AND VEERING LOW-LEVEL FLOW EARLY SUNDAY...THE ATMOSPHERE SHOULD BE UNABLE TO PRODUCE ANY FRONTAL PRECIPITATION. THE EXCEPTION WOULD BE EAST TEXAS...WHERE THE MOISTURE PROFILE WILL BE MORE FAVORABLE...AND THE FRONT WILL ARRIVE DURING THE WARM AFTERNOON HOURS. ABUNDANT APRIL SUNSHINE AND A PRONOUNCED DOWNSLOPE WIND SHOULD OFFSET ANY COLD ADVECTION BEHIND THE FRONT...AND TEMPERATURES SHOULD REACH THE 80S IN MANY AREAS SUNDAY AFTERNOON. THE COOL AIR WILL ARRIVE SUNDAY NIGHT... AND RURAL AREAS IN THE NORTHERN HALF OF THE CWA WILL LIKELY DIP INTO THE 40S MONDAY AND TUESDAY MORNING. ZONAL FLOW WILL PREVAIL MUCH OF THE UPCOMING WEEK. THE NEXT WAVE EMBEDDED IN THIS WESTERLY FLOW WILL ARRIVE AROUND TUESDAY...BUT AT THAT TIME...BOUNDARY LAYER MOISTURE MAY NOT HAVE BEEN ABLE TO SUFFICIENTLY RECOVER. ADDITIONAL RIPPLES WILL FOLLOW...MAINTAINING RAIN CHANCES. HOWEVER...POPS ARE NOTHING MORE THAN CLIMATOLOGY. EXTENDED GUIDANCE IS IN REMARKABLY GOOD AGREEMENT WITH UNSEASONABLE STRONG SHORTWAVE RIDGING AS THE NEXT UPPER LOW ENTERS THE DESERT SOUTHWEST. GFS MOS TEMPS FOR THURSDAY AND FRIDAY ARE NEAR 90 DEGREES. WITH PERFECT PROG 850MB TEMPS AROUND 20C...THIS IS NOT OUT OF THE QUESTION. A BIT CONCERNED THAT CLOUD COVER MAY PUT A DAMPER ON THE SPRING FEVER...AND FOR NOW...WILL KEEP TEMPERATURES CLOSER TO CLIMATOLOGY. 25 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 79 60 80 53 73 / 20 50 10 5 5 WACO, TX 80 60 83 53 75 / 20 50 10 5 5 PARIS, TX 75 58 77 50 70 / 20 40 20 5 0 DENTON, TX 77 57 79 49 72 / 30 50 10 5 5 MCKINNEY, TX 78 58 79 51 73 / 20 50 10 5 0 DALLAS, TX 80 62 81 54 74 / 20 50 10 5 5 TERRELL, TX 78 60 80 52 74 / 20 50 10 5 5 CORSICANA, TX 79 61 82 52 75 / 20 50 20 5 5 TEMPLE, TX 79 60 84 53 74 / 20 50 10 5 5 MINERAL WELLS, TX 81 55 79 48 74 / 40 50 10 5 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 30/92
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1248 PM CDT SAT APR 18 2015 .AVIATION... SAT IMAGERY SUGGESTS INLAND PORTIONS OF SE TX SHOULD START SEEING SOME INTERMITTENT BREAKS OF SUN. ELSEWHERE...EXPECT TO SEE IMPROVING CIG HEIGHTS IN THE NEXT COUPLE HOURS. THERE IS A SFC BOUNDARY NEAR THE COAST...SO ADDITIONAL HEATING ALONG WITH APPROACHING S/W FROM MID TX COAST SHOULD ALLOW FOR AT LEAST SOME SCT TSRA TO DEVELOP THIS AFTN - ESP SOUTH OF A COLUMBUS-LIBERTY LINE. (THIS IS ROUGHLY THE SAME LOCATIONS THAT SAW SOME SIG WX YDAY SO WILL NEED TO KEEP A CLOSE EYE ON THINGS.) AREAS FURTHER N WILL NEED TO KEEP AN EYE ON NW TX. MODELS ARE POINTING TOWARD A DEVELOPING LINE OF SHRA/TSRA OUT THERE THIS AFTN...POSSIBLY MAKING IT ESE TOWARD SE TX LATE EVNG & OVERNIGHT. WILL SEE HOW THIS ALL PLAYS OUT, BUT WENT AHEAD AND THREW THE POTENTIAL OF THIS OCCURRING IN THE 9-2AM TIMEFRAME IN THE CLL, UTS, CXO TAFS. CONSIDERABLE UNCERTAINTY IN THIS ATTM BUT FEEL IT`S ENOUGH TO BEGIN MENTIONING. 47 && .PREV DISCUSSION... /ISSUED 1145 AM CDT SAT APR 18 2015/ A STATIONARY FRONT WAS LOCATED JUST OFFSHORE ALONG THE COAST. THE AIRMASS ALONG ABOUT A TWO-TIER COUNTY WIDTH ALONG THE COAST WAS FAIRLY MOIST. NAMBUFR MODEL SOUNDINGS SHOW INCREASING INSTABILITY DURING THE AFTERNOON WITH HEATING AND AS THE FRONTAL BOUNDARY DRIFTS BACK INLAND. WATER VAPOR OVER THE PAST FEW HOURS SHOWED AN APPROACHING SHORTWAVE TROUGH MOVING TOWARD THE AREA FROM THE SOUTH. THE 06Z TEXAS TECH WRF AND 15Z HRRR BOTH FORECASTED BEST CHANCES STARTING NEAR THE COAST BASICALLY ALONG AND EAST OF THE HIGHWAY 59 CORRIDOR FROM MID AFTERNOON THROUGH MID EVENING. ANOTHER UPPER LEVEL SHORTWAVE TROUGH WILL MOVE ACROSS SE TEXAS LATE THIS EVENING FROM THE WEST. THIS MAY HELP GENERATE ADDITIONAL SCATTERED STORMS DURING THE LATE EVENING AND INTO THE OVERNIGHT PERIOD. TWEAKED RAIN CHANCES MAINLY FOR TONIGHT AND ALSO TEMPERATURES FOR TODAY. 40 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 79 62 85 56 75 / 30 40 10 0 0 HOUSTON (IAH) 80 64 84 60 78 / 50 30 20 10 0 GALVESTON (GLS) 77 69 81 67 75 / 40 30 20 20 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1201 PM CDT SAT APR 18 2015 .UPDATE... CONVECTION HAS BEEN A LITTLE SLOWER TO BEGIN THIS MORNING. HAVE REDUCED POPS FOR THE NEXT COUPLE OF HOURS...ESPECIALLY ACROSS THE EASTERN HALF OF THE CWA. SPC HAS UPDATED THE DAY ONE OUTLOOK AND INCREASED OUR RISK TO ENHANCED. EXPECTING STRONG TO SEVERE STORMS TO FORM LATER THIS AFTERNOON ALONG THE DRYLINE WHICH CURRENTLY STRETCHES FROM AROUND CHILDRESS TO MIDLAND TO THE BIG BEND. THESE STORMS WILL MOVE EASTWARD AND INTO OUR NORTHERN AREA LATE THIS AFTERNOON OR EARLY EVENING. THE MAIN THREAT LOOKS TO BE LARGE HAIL AND DAMAGING WINDS. THERE IS ALSO A LESSER THREAT FOR TORNADOES. WITH ALL OF THE RAIN OVER THE PAST COUPLE OF DAYS LOCALLY HEAVY RAINFALL IN STORMS WILL RUNOFF QUICKLY AND MAY CAUSE FLASH FLOODING...BUT THIS IS NOT A WIDESPREAD THREAT. && .PREV DISCUSSION... /ISSUED 611 AM CDT SAT APR 18 2015/ AVIATION... CEILINGS ARE IFR/MVFR AROUND THE AREA AIRPORTS THIS MORNING AND CONDITIONS SHOULD SLOWLY IMPROVE TO VFR BY EARLY AFTERNOON. CONVECTION HAS DEVELOPED WEST OF KDRT AND WILL SHOW VCTS FOR THE FIRST FEW HOURS OF THE VALID TAF PERIOD. CONFIDENCE REGARDING CONVECTION CHANCES THIS AFTERNOON IS NOT VERY HIGH. THE MOST LIKELY SCENARIO IS FOR THIS ELEVATED CONVECTION TO MOVE EAST THIS MORNING AND THE ATMOSPHERE TO REENERGIZE BY THE LATE AFTERNOON HOURS. THERE SHOULD BE A SURFACE CONVERGENCE ZONE DEVELOPING WEST OF THE I-35 TAF SITES. THE MOST LIKELY TIME THESE WOULD BE TO THE TERMINALS WOULD BE AROUND 22-03Z. WILL HANDLE THIS WITH A VCTS FOR NOW. ADDITIONAL MVFR RESTRICTIONS ARE POSSIBLE TONIGHT...BUT IFR IS NOT ANTICIPATED AS SLIGHTLY DRIER AIR MOVES INTO THE AREA. HAMPSHIRE PREV DISCUSSION... /ISSUED 401 AM CDT SAT APR 18 2015/ SHORT TERM (TODAY THROUGH SUNDAY)... AN UPPER LEVEL STORM SYSTEM IS CENTERED ACROSS COLORADO EARLY THIS MORNING. THIS SYSTEM IS FORECAST TO MOVE TO THE NORTHEAST AND THEN EAST THROUGH THE WEEKEND AND BECOMES AN OPEN WAVE LATE SUNDAY AFTERNOON. SEVERAL SHORT WAVES ASSOCIATED WITH THE UPPER LEVEL LOW ARE ANTICIPATED TO PUSH ACROSS THE AREA FOR THE NEXT 12 TO 18 HOURS AND ENHANCE STORM DEVELOPMENT LATE THIS MORNING THROUGH THE EVENING HOURS. AT LOWER LEVELS...A PRE-FRONTAL TROUGH/DRY-LINE WILL SERVE AS THE MAIN FOCUS AS STORMS FORM IN THE MOIST AND WARM SECTOR. BY THIS AFTERNOON...DEWPOINT TEMPERATURES ARE FORECAST TO REACH THE MID TO UPPER 60S WITH AREA SOUNDINGS SUGGESTING ML CAPES OF 1500 TO 2500J/KG AND LI RANGING FROM -5 TO -10 FOR LARGE TO EXTREME INSTABILITY. THEREFORE...ANY STORM THAT DOES DEVELOP HAS THE POTENTIAL TO BECOME STRONG OR SEVERE. PER SPC DAY 1 CONVECTIVE OUTLOOK...ALL OF SOUTH CENTRAL TEXAS WITH THE EXCEPTION OF THE NORTHWEST PORTION OF VAL VERDE COUNTY...IS UNDER A SLIGHT RISK OF SEVERE THUNDERSTORMS. HIRES SOLUTIONS ARE HAVING DIFFICULTIES ON TIMING AND AREAS OF STORM DEVELOPMENT INITIALLY. THE HRRR STARTS CONVECTION ACROSS THE SOUTHERN COUNTIES AS AN MCS DEVELOPS ACROSS THE COASTAL PLAINS AND MOVE TO THE EAST. THE TEXAS TECH IS MORE AGGRESSIVE ON FORMING STORMS AHEAD OF THE DRY-LINE AS IT PUSHES TO THE EAST AND OVER THE EDWARDS PLATEAU/HILL COUNTRY AREA. THE HRRR DOES DEVELOP CONVECTION AHEAD OF THE DRY-LINE THIS AFTERNOON BUT NOWHERE NEAR TEXAS TECH MODEL. THEREFORE...THE SHORT-TERM/FIRST PERIOD CONSISTS ON A BLEND OF THE HRRR/TEXAS TECH SOLUTIONS. BY LATER THIS EVENING...MID LEVEL WESTERLY WILL TAKE OVER AS THE UPPER LEVEL LOW PUSHES TO THE EAST...MARKING THE END OF RAIN CHANCES THROUGH MONDAY. WITH A WESTERLY FLOW IN PLACE FOR SUNDAY...EXPECT A NICE WARMUP WITH HIGHS IN THE UPPER 80S AND LOWER 90S. CAN NOT RULE OUT AN ISOLATED STORM ACROSS THE FAR EASTERN COUNTIES SUNDAY AFTERNOON AS LINGERING INSTABILITY REMAINS. A BACK DOOR COLD FRONT WILL PUSH ACROSS THE AREA SUNDAY EVENING TO COOL THE OVERNIGHT TEMPS INTO THE 50S AREAWIDE. LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)... A CLEAR NIGHT IS IN STORE FOR SUNDAY NIGHT WITH NORTHERLY WINDS AND COOL TEMPERATURES FOLLOWED BY A PARTLY CLOUDY DAY ON MONDAY. SOUTHERLY FLOW RETURNS TUESDAY AS WELL AS THE RAIN CHANCES FOR SOUTH CENTRAL TEXAS. SEVERAL SHORT WAVES ARE EXPECTED TO PASS BY AND TRIGGER SHOWERS AND STORMS THROUGH FRIDAY. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 81 61 89 57 76 / 40 40 - - - AUSTIN BERGSTROM INTL AIRPORT 81 60 87 55 76 / 50 40 - - - NEW BRAUNFELS MUNI AIRPORT 81 60 87 56 76 / 50 30 0 - - BURNET MUNI AIRPORT 79 57 87 53 74 / 40 40 - - - DEL RIO INTL AIRPORT 86 59 90 59 79 / 30 10 0 - 10 GEORGETOWN MUNI AIRPORT 79 59 87 54 74 / 40 40 10 - - HONDO MUNI AIRPORT 82 59 88 57 78 / 40 20 0 - - SAN MARCOS MUNI AIRPORT 81 61 86 56 75 / 50 40 0 - - LA GRANGE - FAYETTE REGIONAL 80 63 86 57 75 / 50 40 20 10 10 SAN ANTONIO INTL AIRPORT 81 61 88 58 77 / 40 30 0 - - STINSON MUNI AIRPORT 82 61 88 59 77 / 40 20 - - - && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...04 SYNOPTIC/GRIDS...05 PUBLIC SERVICE/DATA COLLECTION...01
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1145 AM CDT SAT APR 18 2015 .DISCUSSION... A STATIONARY FRONT WAS LOCATED JUST OFFSHORE ALONG THE COAST. THE AIRMASS ALONG ABOUT A TWO-TIER COUNTY WIDTH ALONG THE COAST WAS FAIRLY MOIST. NAMBUFR MODEL SOUNDINGS SHOW INCREASING INSTABILITY DURING THE AFTERNOON WITH HEATING AND AS THE FRONTAL BOUNDARY DRIFTS BACK INLAND. WATER VAPOR OVER THE PAST FEW HOURS SHOWED AN APPROACHING SHORTWAVE TROUGH MOVING TOWARD THE AREA FROM THE SOUTH. THE 06Z TEXAS TECH WRF AND 15Z HRRR BOTH FORECASTED BEST CHANCES STARTING NEAR THE COAST BASICALLY ALONG AND EAST OF THE HIGHWAY 59 CORRIDOR FROM MID AFTERNOON THROUGH MID EVENING. ANOTHER UPPER LEVEL SHORTWAVE TROUGH WILL MOVE ACROSS SE TEXAS LATE THIS EVENING FROM THE WEST. THIS MAY HELP GENERATE ADDITIONAL SCATTERED STORMS DURING THE LATE EVENING AND INTO THE OVERNIGHT PERIOD. TWEAKED RAIN CHANCES MAINLY FOR TONIGHT AND ALSO TEMPERATURES FOR TODAY. 40 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 79 62 85 56 75 / 30 40 10 0 0 HOUSTON (IAH) 80 64 84 60 78 / 50 30 20 10 0 GALVESTON (GLS) 77 69 81 67 75 / 40 30 20 20 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...40 AVIATION/MARINE...41
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
401 PM EDT SAT APR 18 2015 .SYNOPSIS... A RIDGE OF HIGH PRESSURE OVER OUR AREA TODAY WILL MOVE EAST ALLOWING A MOISTURE EASTERLY FLOW TO DEVELOP TONIGHT. A COMPLEX STORM SYSTEM PASSING TO THE WEST WILL RESULT IN MORE WIDESPREAD RAIN...HEAVY AT TIMES...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 SUNDAY/... 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 /SUNDAY NIGHT 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 /20Z SATURDAY THROUGH THURSDAY/... AS OF 120 PM EDT SATURDAY... VFR CONDITIONS WERE NOTED AT ALL THE TAF SITES EARLY THIS AFTERNOON...BUT FLYING CONDITIONS ARE FORECAST TO DETERIORATE DURING THE OVERNIGHT HOURS/EARLY MORNING SUNDAY. FOR THE REMINDER OF TODAY...WEAK CONVERGENCE AND UPSLOPE MAY GENERATE ISOLD SHWRS OR TSTORMS THIS AFTERNOON...ESPECIALLY NEAR BLUE RIDGE ALONG OR SOUTH OF VA/NC BORDER...BUT PROBABILITY IS TOO LOW TO INCLUDE IN ANY OF THE TAFS AT THIS TIME. MODELS HAVE BEEN CONSISTENT WITH CLOUDS AND THEN RAIN WILL SPREAD INTO THE AREA FROM SOUTHWEST TO NORTHEAST TONIGHT. EXPECT CEILINGS TO LOWER TO MVFR AFTER 08Z. HIGHEST CONFIDENCE IN MVFR CEILINGS IS AT KBCB AFTER 08Z/2AM. A STRONG SOUTHEAST LOW LEVEL JET WILL DEVELOP JUST AFTER MIDNIGHT WHICH MAY BRING WIND GUSTS TO 30 KTS AT KLBF EARLY SUNDAY AND CONTINUE THROUGH 18Z. WITH A WEDGE OF HIGH PRESSURE IN PLACE ALONG AND EAST OF THE BLUE RIDGE...THESE STRONG WINDS ARE NOT EXPECTED TO REACH THE SURFACE AND KBCB AND KLWB...BUT WILL CREATE POTENTIALLY HAZARDOUS LOW LEVEL WIND SHEAR CONDITIONS. KROA WILL BE NEED TO BE CAREFULLY MONITORED TO POSSIBLE INCLUSION OF LL WIND SHEAR. CIGS WILL CONTINUE TO DROP AND RAIN WILL BECOME WIDESPREAD DURING THE DAY SUNDAY...AS A STRONG UPSLOPE FLOW TRANSPORTS ABUNDANT MOISTURE INTO THE REGION NORTH OF A NEARLY STATIONARY FRONT. WIDESPREAD IFR CONDITIONS ARE FORECAST IN THE MOUNTAINS AND FOOTHILLS...WITH MVFR CIGS AT KLYH AND KDAN LIKELY DETERIORATING AFTER 18Z SUNDAY WHEN THE HEAVIEST PRECIPITATION MOVES ARRIVES. EXTENDED AVIATION... A COMPLEX STORM SYSTEM WILL BEGIN TO AFFECT THE REGION SUNDAY WITH A WARM FRONT BRINGING WIDESPREAD MVFR/IFR CONDITIONS IN RAIN INTO SUNDAY NIGHT. THIS WILL BE FOLLOWED BY ANOTHER COLD FRONT MONDAY. THIS IS LIKELY TO KEEP PERIODS OF MVFR IN PLACE UNTIL THE FRONT POSSIBLY CLEARS THE REGION. 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. .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 FROM LATE TONIGHT THROUGH SUNDAY EVENING FOR VAZ015>017-032. NC...FLOOD WATCH FROM LATE TONIGHT THROUGH SUNDAY EVENING FOR NCZ001>003-018>020. WV...NONE. && $$ SYNOPSIS...PH NEAR TERM...PH SHORT TERM...RAB LONG TERM...RAB AVIATION...AMS/PH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1128 AM CDT SAT APR 18 2015 UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE .UPDATE... ISSUED AT 407 AM CDT SAT APR 18 2015 AFTER FURTHER COORDINATION WITH ARX AND THE DNR...WILL ISSUE A RED FLAG WARNING FOR WOOD COUNTY. THE COMBO OF HUMIDITIES FALLING NEAR 20 PCT THIS AFTERNOON...MAX TEMPS IN THE 60S...WIND SPEEDS OF 10 TO 20 MPH...AND DRY FUELS WILL LEAD TO A CRITICAL FIRE WEATHER DAY THERE. THIS RED FLAG WARNING WILL TARGET THE PINE COUNTRY OF CENTRAL WISCONSIN. ADDITIONALLY...THE COLD FRONT HAS JUST PASSED OVER GREEN BAY. WINDS HAVE SHIFTED TO THE NORTH AND ARE GUSTING TO 22 KNOTS AT THE GRB AIRPORT. SOME GUSTS UP TO 25 KNOTS OVER THE BAY ARE ALSO OCCURRING. && .SHORT TERM...TODAY...TONIGHT...AND SUNDAY ISSUED AT 330 AM CDT SAT APR 18 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A FAIRLY POTENT COLD FRONT DROPPING SOUTH OVER FAR N-C WISCONSIN AND THE CENTRAL UPPER PENINSULA. NORTH WINDS BEHIND THE FRONT COMBINED WITH IMPRESSIVE PRESSURE RISES ARE CONTRIBUTING TO WIND GUSTS OVER 30 KTS OVER LAKE SUPERIOR. AS THE FRONT MOVES ACROSS NORTHERN WISCONSIN EARLY THIS MORNING...EXPECT NORTH WINDS TO STRENGTHEN AND BECOME GUSTY FOR PERIOD. ELSEWHERE...UPPER LEVEL LOW PRESSURE CONTINUES TO SPIN OVER THE CENTRAL ROCKIES AND PRODUCE SHOWERS AND THUNDERSTORMS ACROSS THE CENTRAL GREAT PLAINS. FORECAST CONCERNS INCLUDE FIRE WEATHER PARAMETERS TODAY...AND PRECIP CHANCES ON SUNDAY. TODAY...THE DRY COLD FRONT WILL DROP SOUTH ACROSS THE REST OF NORTHERN WISCONSIN EARLY THIS MORNING AND CENTRAL WISCONSIN BY MID-MORNING. BEHIND THE FRONT...THE MODELS ARE STILL DEPICTING VERY DRY AIR TO MOVE INTO NORTH-CENTRAL TO EAST-CENTRAL WISCONSIN TODAY. THOUGH NORTHEAST WINDS OFF LAKE MICHIGAN WILL HELP MODERATE THE DRY AIR OVER EASTERN WISCONSIN...MODEST WIND SPEEDS SHOULD BE ABLE TO TAP INTO THIS VERY DRY AIR JUST ABOVE THE INVERSION...AROUND 900MB. SO WAS AGGRESSIVE IN DROPPING HUMIDITIES TODAY...WHICH SHOULD FALL INTO THE TEENS OVER N-C WISCONSIN AND TO AROUND 25 PCT OVER CENTRAL WISCONSIN. EAST WINDS WILL ALSO BE APPROACHING CRITICALLY SUSTAINED SPEEDS OVER CENTRAL WISCONSIN THIS AFTERNOON. STILL WAITING FOR A FINAL DECISION FROM THE DNR CONCERNING A RED FLAG WARNING...WHICH SHOULD HAVE BY 5 AM. OTHERWISE...WILL SEE A SUNNY AND COOLER DAY. HIGHS IN THE LOW TO MID 60S AWAY FROM LAKE MICHIGAN. TONIGHT...CLOUDS WILL BE ON THE INCREASE AS THE CENTRAL ROCKIES UPPER LOW MOVES ACROSS THE CENTRAL PLAINS...WHILE A NORTHERN STREAM WAVE DIGS OVER THE NORTHERN PLAINS. AS CLOUDS THICKEN AND LOWER...WINDS BELOW 900MB WILL REMAIN OUT OF THE SOUTHEAST AND CONTINUE TO ADVECT VERY DRY AIR OVER THE REGION. THIS DRY AIR WILL HAVE TO BE OVERCOME...AND THIS MAY NOT OCCUR UNTIL LATE IN THE NIGHT OVER THE WEST. WILL MODIFY PRECIP CHANCES SLIGHTLY TO REFLECT THIS. LOWS RANGING FROM THE MID 30S NORTH TO THE MID 40S SOUTHWEST. SUNDAY...MID-LEVEL HEIGHT FALLS WILL CONTINUE TO ADVANCE INTO THE WESTERN GREAT LAKES. ONE AREA OF LOW PRESSURE WILL MOVE INTO WESTERN WISCONSIN DURING THE AFTERNOON...WHILE A SOUTHERN STREAM LOW SWINGS NE TOWARDS THE SOUTHERN TIP OF LAKE MICHIGAN. FORCING WILL IMPROVE THROUGH THE DAY AHEAD OF THESE FEATURES...THOUGH THE LEAD BAND OF LIGHT RAIN MAY DECAY DURING THE MORNING AS A RESULT OF THE DRY LOW LEVEL FLOW. THEN A SECOND ROUND OF PRECIP MAY TRY TO MOVE INTO THE AREA WITH THE APPROACHING LOW PRESSURE SYSTEMS. TEMPS ARE DIFFICULT BECAUSE OF THE PRECIP POTENTIAL...AMPLE CLOUD COVER...AND EAST WINDS. HAVE DROPPED TEMPS SOME SINCE TEMPS DO NOT TYPICALLY RISE WELL WHEN THERE IS CLOUD COVER AND EAST WINDS. PRECIP WILL ALSO LIKELY HOLD TEMPS BACK OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. SO WENT WITH HIGHS RANGING FROM THE MID 50S NORTH TO LOW 60S SOUTH. .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY ISSUED AT 330 AM CDT SAT APR 18 2015 500MB TROUGH WILL EVOLVE INTO A CLOSED UPPER LOW OVER THE WESTERN GREAT LAKES REGION EARLY NEXT WEEK...THEN MEANDER ACROSS EASTERN CANADA AND THE GREAT LAKES REGION THROUGH THE END OF NEXT WEEK. THIS WILL LEAD TO COOL AND UNSETTLED CONDITIONS...ALONG WITH A CHANCE OF SNOW LATE AT NIGHT AND EARLY MORNING HOURS. RAINFALL TOTALS STILL PROBLEMATIC SUNDAY NIGHT AS TWO SEPARATE SYSTEMS WILL BRING RAIN TO THE AREA. NORTHERN STREAM SYSTEM WILL BRING RAIN TO THE WESTERN HALF OF THE STATE...MEANWHILE A FAIRLY POTENT LOW PRESSURE SYSTEM WILL MOVE NORTHEAST INTO THE GREAT LAKES REGION SUNDAY NIGHT. STILL A LOT OF QUESTIONS ON TRACK OF SYSTEM DUE TO CLOSING UPPER LOW NORTHWEST OF THE STATE. MODEL QPF WOULD SUGGEST THAT MUCH NEEDED RAIN WOULD FALL ACROSS THE REGION. MAIN QUESTION IS WHERE AXIS OF HEAVIER RAIN WOULD FALL. MODEL RUN TO RUN CONTINUITY HAS NOT BEEN CONSISTENT...THUS LOW CONFIDENCE IN THE RAINFALL AMOUNT FORECAST. MONDAY IS NOT MUCH CLEARER AS SOME OF THE MODELS BRING DRY SLOT ACROSS THE AREA WITH A SIGNIFICANT DOWNWARD TREND IN RAINFALL AMOUNTS. THE ECMWF/CANADIAN DO NOT SHARE THIS TREND WITH THE WRF/GFS...THUS WILL KEEP SCATTERED DEPICTION/WORDING IN THE FORECAST. AS UPPER LOW CLOSES MONDAY NIGHT THROUGH WEDNESDAY...COOL CYCLONIC FLOW AND WEAK DISTURBANCES MOVING THROUGH THE MEAN FLOW WILL BRING CHANCES OF RAIN AND SNOW SHOWERS DEPENDING ON LOCATION AND TIMING OF THE DAY. AT SOME POINT...THERE COULD BE A MINOR ACCUMULATION OF SNOW ACROSS THE NORTH. SOME MODERATION IN TEMPERATURES IS EXPECTED BY THE END OF THE WEEK AS THE UPPER LOW GRADUALLY SHIFTS EAST OF THE AREA. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1102 AM CDT SAT APR 18 2015 VFR CONDITIONS EXPECTED THROUGH THIS AFTERNOON. GUSTY ENE WINDS TO CONTINUE BEFORE DIMINISHING THIS EVENING...WITH THE GUSTIEST WINDS IN EASTERN TAF SITES. DRY CONDITIONS WILL HOLD THROUGH THE NIGHT...WITH INCREASING VFR CLOUD COVER FROM SW TO NE THROUGH THE NIGHT. LLWS THROUGH ABOUT 1500FT WILL DEVELOP AFTER MIDNIGHT...AND THEN DIMINISH SUNDAY MORNING AS WINDS MIX AGAIN. VFR CIGS WILL STICK AROUND SUNDAY...WITH RAIN SHOWERS POSSIBLE IN NORTH-CENTRAL WISCONSIN AFTER DAYBREAK AS A LOW PRESSURE SYSTEM LIFTS TO THE NORTH AND WEST OF THE STATE...WITH ONLY VERY LIGHT RAIN AND PCPN EXPECTED. EASTERN TAF SITES SHOULD STAY DRY UNTIL AT LEAST MIDDAY IF NOT MOST OF SUNDAY. && .GRB WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR WIZ035. && $$ UPDATE.........MPC SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......ALLEN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
243 PM MDT SAT APR 18 2015 .UPDATE... ISSUED AT 239 PM MDT SAT APR 18 2015 TORNADO WATCH ISSUED FOR CHEYENNE COUNTY AND MORRILL COUNTY IN THE SOUTHERN NEBRASKA PANHANDLE UNTIL 8 PM. BASED ON CURRENT MESOSCALE ANALYSIS...THE MAIN THREATS ARE MARGINAL SEVERE HAIL AND FUNNEL CLOUDS THIS AFTERNOON...BUT AN ISOLATED BRIEF TORNADO IS NOT OUT OF THE QUESTION IN THE WATCH COUNTIES. MOST LIKELY THE BOUNDARY LAYER WILL STABILIZE OVER THE NEXT SEVERAL HOURS AS COLD OUTFLOW FROM SHOWERS AND THUNDERSTORMS SPREAD ACROSS THE AREA...ENDING ANY THREAT FOR TORNADOS. UPDATE ISSUED AT 1135 AM MDT SAT APR 18 2015 ADJUSTED WINTER WEATHER HEADLINES FOR THE BAND OF HEAVY SNOW WHICH IS EXPECTED TO CONTINUE OVER NORTHERN ALBANY COUNTY AND EASTERN/CENTRAL CARBON COUNTY TODAY. ADDED THE ARLINGTON ZONE TO THE WARNING BASE ON LATEST GFS AND NAM SHOWING HEAVY PRECIPITATION ACROSS THIS AREA THROUGH EARLY THIS EVENING. LATEST RADAR SHOWING THE BAND OF HEAVY TROWAL PRECIPITATION SETTING UP AT THIS TIME AND SURFACE OBS AND WEB CAMS VERIFY THE HEAVY SNOW. MODEL SURFACE TEMPERATURES AND MOS GUIDANCE MOST LIKELY TOO WARM AROUND ARLINGTON GIVEN WHAT WILL BE HEAVY PRECIPITATION. EAST AND WEST OF THIS PRECIPITATION BAND...TEMPERATURES WILL WARM AS EXPECTED. IMPACTS ON ROADS IS A BIT OF A QUESTION WITH TEMPERATURES NEAR FREEZING AND HIGH SUN ANGLE THAT MAY BE ABLE TO MELT MUCH OF THE SNOW...EVEN WITHIN THE HEAVY BAND. REGARDLESS ROADS WILL AT LEAST BE SLUSHY AT TIMES...IF NOT COMPLETELY SNOW COVERED. MOST SNOW ACCUMULATIONS WILL BE ON ELEVATED SURFACES AND OVER CURRENT SNOW COVER. WINTER WEATHER HEADLINES HAVE BEEN CANCELLED FOR THE SOUTHERN LARAMIE RANGE AND FOOTHILLS WITH THE BAND OF SNOW SETTING UP WEST OF THE THIS AREA. THERE IS THE POTENTIAL FOR SOME SNOW SHOWERS THIS AFTERNOON. AS THE TROWAL SHIFTS EAST THIS EVENING THERE WILL LIKELY BE A PERIOD OF SNOW OVER THE SOUTHERN LARAMIE RANGE BUT ACCUMULATIONS WILL BE MINIMAL...MAYBE AN INCH OR TWO OF NEW ACCUMULATIONS. UPDATE ISSUED AT 1009 AM MDT SAT APR 18 2015 ADJUSTED POPS SLIGHTLY TO REFLECT THE POSITION OF THE TROWAL THIS MORNING. THE TROWAL WHICH IS VERY DISTINGUISHABLE ON SATELLITE AND RADAR WILL MOVE SLIGHTLY WESTWARD THROUGH EARLY AFTERNOON. AT THAT POINT IT WILL STALL AND THEN SHIFT EAST INTO THIS EVENING AS A NORTHERN STREAM KICKER PUSHES THE CLOSED UPPER LOW INTO THE PLAINS. LOWERED TEMPERATURES ACROSS THE WEST TODAY AS TROWAL PRECIPITATION WILL HOLD TEMPERATURES DOWN...KEEPING MOST PRECIPITATION WEST OF THE LARAMIE RANGE AS SNOW BUT SOME PLACES WILL MIX WITH OR CHANGE TO RAIN. WILL KEEP AN EYE ON THINGS BUT MAY NEED TO LOWER TEMPERATURES IN THE WEST A BIT MORE. LARAMIE SHOULD SEE SNOW THROUGH THE DAY WITH SEVERAL MORE INCHES OF SNOWFALL. WITH TEMPERATURES NEAR FREEZING AROUND LARAMIE AND THE RELATIVELY HIGH APRIL SUN ANGLE...NOT MUCH SNOW WILL ACCUMULATE ON ROADS WAYS WITH WET TO SLUSHY ROADS EXPECTED. EAST OF THE LARAMIE RANGE THERE IS THE POTENTIAL FOR THUNDERSTORMS THIS AFTERNOON. MODELS SHOWING 500-1000 J/KG OF MOST UNSTABLE CAPE. SHEAR VALUES ARE NOT IMPRESSIVE...BUT GIVEN THE COLD NATURE OF THIS SYSTEM...IT IS LIKELY THERE WILL BE SOME SMALL HAIL TODAY AND WITH LOW FREEZING LEVELS...MARGINAL SEVERE HAIL NOT OUT OF THE QUESTION WITH ANY STRONGER UPDRAFTS. && .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 415 AM MDT SAT APR 18 2015 TODAY...SLOW MOVING CLOSED UPPER LOW PROGGED TO MOVE FROM CENTRAL COLORADO THIS MORNING TO EAST CENTRAL COLORADO BY DINNER TIME. ALL MODELS INCLUDING THE HRRR SHOW A BAND OF PRECIPITATION SWINGING WESTWARD ACROSS OUR COUNTIES THIS MORNING AND AFTERNOON WITH DECENT UPWARD VERTICAL MOTION AND QUASIGEOSTROPHIC FORCING...THUS HAVE OPTED TO EXTEND OUR WINTER WEATHER ADVISORIES AND WINTER STORM WARNINGS THROUGH MIDDAY...WHILE DROPPING CHEYENNE FROM THE ADVISORY WITH TEMPERATURES LIKELY REMAINING ABOVE FREEZING AND THUS MINIMAL IMPACTS TO TRAVEL. TONIGHT...FINALLY...THE UPPER TROUGH OPENS UP AS A NORTHERN STREAM SHORTWAVE TROUGH ALOFT MOVES EASTWARD INTO WESTERN NORTH DAKOTA...THUS PRECIPITATION CHANCES DWINDLE AS THE NIGHT PROGRESSES. SUNDAY...BREEZY TO WINDY...AND COOL WITH BRISK NORTHWEST FLOW ALOFT AND DEEP UNIDIRECTIONAL WINDS. LOOKS LIKE ENOUGH LOW AND MID LEVEL MOISTURE FOR ISOLATED TO SCATTERED SHOWERS OVER AND NEAR OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES...WITH MOSTLY DRY CONDITIONS ELSEWHERE. SUNDAY NIGHT...MOIST OROGRAPHIC NORTHWEST FLOW ALOFT CONTINUES PRODUCING SCATTERED TO NUMEROUS SNOW SHOWERS OVER AND NEAR OUR SNOWY...SIERRA MADRE AND LARAMIE RANGES...DRY ELSEWHERE. .LONG TERM...(MONDAY THROUGH FRIDAY) ISSUED AT 415 AM MDT SAT APR 18 2015N THE EXTENDED PERIOD WILL START OUT TRANQUIL AND THEN END POTENTIALLY UNSETTLED. NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE ON MON WITH A WEAK SHORTWAVE MOVING OVERHEAD DURING THE DAY. COULD BE SOME LIGHT SNOW SHOWERS OVER THE SIERRA MADRE AND SNOWY RANGES...BUT MUCH OF THE ACTIVITY WILL BE CONFINED TO NORTHERN COLORADO. WITH 700MB TEMPS AROUND -6C...IT WILL BE ANOTHER DAY OF BELOW NORMAL TEMPS. WE FINALLY GET TEMPS TO MODERATE SOME BY TUES AND ESPECIALLY INTO WED...BACK INTO THE 50S AND 60S TO THE EAST OF THE LARAMIE RANGE. A BUILDING SFC HIGH OVER THE NORTHERN PLAINS ON THURS WILL CAUSE SOUTHEAST WINDS TO DEVELOP ACROSS THE PLAINS. WEAK INSTABILITY WILL BE PRESENT ON THURS AFTN...SO INCLUDED A SLIGHT OF TSTMS. A SHORTWAVE WILL THEN LIFT NORTHEASTWARD FROM ARIZONA INTO COLORADO ON FRI. BOTH THE GFS AND ECMWF INDICATE THE BEST CHANCE OF WIDESPREAD PRECIP COULD BE FRI AFTN INTO FRI NIGHT WITH GOOD EASTERLY UPSLOPE FLOW OVER THE PLAINS. 700MB TEMPS ARE AROUND -2C...SO COULD BE DEALING WITH ANOTHER CASE WHERE SNOW IS LARGELY CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE. && .AVIATION...(FOR THE 18Z TAFS THROUGH SUNDAY MORNING) THE LARGE AREA OF LIGHT SNOW IS CURRENTLY ALONG AND JUST WEST OF THE LARAMIE RANGE AND MOVING SLIGHTLY WESTWARD. IFR CONDITIONS AND LIGHT SNOW WILL CONTINUE BETWEEN KRWL AND KLAR THIS AFTERNOON...WITH MVFR CONDITIONS EXPECTED AT KRWL...AND IFR CONDITIONS AT KLAR. IFR CONDITIONS DUE TO LOW CIGS WILL CONTINUE AT KCYS...BUT CONDITIONS SHOULD IMPROVE A BIT THROUGH THE AFTERNOON AS SHOWERS BEGIN TO DEVELOP TO THE SOUTH. A COLD FRONT WILL PUSH ACROSS THE PLAINS BY LATE THIS EVENING (AFTER 03Z) WITH BREEZY NORTH WINDS EXPECTED. && .FIRE WEATHER... ISSUED AT 402 AM MDT SAT APR 18 2015 NO FIRE WEATHER ISSUES WITH RECENT WIDESPREAD PRECIPITATION...AND PROJECTED HUMIDITIES AND WINDS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...WINTER STORM WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ110-114. WINTER WEATHER ADVISORY UNTIL 9 PM MDT THIS EVENING FOR WYZ103- 105-106-112-113-115. NE...NONE. && $$ UPDATE...SML SHORT TERM...RUBIN LONG TERM...ZF AVIATION...TJT FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1136 AM MDT SAT APR 18 2015 .UPDATE... ISSUED AT 1135 AM MDT SAT APR 18 2015 ADJUSTED WINTER WEATHER HEADLINES FOR THE BAND OF HEAVY SNOW WHICH IS EXPECTED TO CONTINUE OVER NORTHERN ALBANY COUNTY AND EASTERN/CENTRAL CARBON COUNTY TODAY. ADDED THE ARLINGTON ZONE TO THE WARNING BASE ON LATEST GFS AND NAM SHOWING HEAVY PRECIPITATION ACROSS THIS AREA THROUGH EARLY THIS EVENING. LATEST RADAR SHOWING THE BAND OF HEAVY TROWAL PRECIPITATION SETTING UP AT THIS TIME AND SURFACE OBS AND WEB CAMS VERIFY THE HEAVY SNOW. MODEL SURFACE TEMPERATURES AND MOS GUIDANCE MOST LIKELY TOO WARM AROUND ARLINGTON GIVEN WHAT WILL BE HEAVY PRECIPITATION. EAST AND WEST OF THIS PRECIPITATION BAND...TEMPERATURES WILL WARM AS EXPECTED. IMPACTS ON ROADS IS A BIT OF A QUESTION WITH TEMPERATURES NEAR FREEZING AND HIGH SUN ANGLE THAT MAY BE ABLE TO MELT MUCH OF THE SNOW...EVEN WITHIN THE HEAVY BAND. REGARDLESS ROADS WILL AT LEAST BE SLUSHY AT TIMES...IF NOT COMPLETELY SNOW COVERED. MOST SNOW ACCUMULATIONS WILL BE ON ELEVATED SURFACES AND OVER CURRENT SNOW COVER. WINTER WEATHER HEADLINES HAVE BEEN CANCELLED FOR THE SOUTHERN LARAMIE RANGE AND FOOTHILLS WITH THE BAND OF SNOW SETTING UP WEST OF THE THIS AREA. THERE IS THE POTENTIAL FOR SOME SNOW SHOWERS THIS AFTERNOON. AS THE TROWAL SHIFTS EAST THIS EVENING THERE WILL LIKELY BE A PERIOD OF SNOW OVER THE SOUTHERN LARAMIE RANGE BUT ACCUMULATIONS WILL BE MINIMAL...MAYBE AN INCH OR TWO OF NEW ACCUMULATIONS. UPDATE ISSUED AT 1009 AM MDT SAT APR 18 2015 ADJUSTED POPS SLIGHTLY TO REFLECT THE POSITION OF THE TROWAL THIS MORNING. THE TROWAL WHICH IS VERY DISTINGUISHABLE ON SATELLITE AND RADAR WILL MOVE SLIGHTLY WESTWARD THROUGH EARLY AFTERNOON. AT THAT POINT IT WILL STALL AND THEN SHIFT EAST INTO THIS EVENING AS A NORTHERN STREAM KICKER PUSHES THE CLOSED UPPER LOW INTO THE PLAINS. LOWERED TEMPERATURES ACROSS THE WEST TODAY AS TROWAL PRECIPITATION WILL HOLD TEMPERATURES DOWN...KEEPING MOST PRECIPITATION WEST OF THE LARAMIE RANGE AS SNOW BUT SOME PLACES WILL MIX WITH OR CHANGE TO RAIN. WILL KEEP AN EYE ON THINGS BUT MAY NEED TO LOWER TEMPERATURES IN THE WEST A BIT MORE. LARAMIE SHOULD SEE SNOW THROUGH THE DAY WITH SEVERAL MORE INCHES OF SNOWFALL. WITH TEMPERATURES NEAR FREEZING AROUND LARAMIE AND THE RELATIVELY HIGH APRIL SUN ANGLE...NOT MUCH SNOW WILL ACCUMULATE ON ROADS WAYS WITH WET TO SLUSHY ROADS EXPECTED. EAST OF THE LARAMIE RANGE THERE IS THE POTENTIAL FOR THUNDERSTORMS THIS AFTERNOON. MODELS SHOWING 500-1000 J/KG OF MOST UNSTABLE CAPE. SHEAR VALUES ARE NOT IMPRESSIVE...BUT GIVEN THE COLD NATURE OF THIS SYSTEM...IT IS LIKELY THERE WILL BE SOME SMALL HAIL TODAY AND WITH LOW FREEZING LEVELS...MARGINAL SEVERE HAIL NOT OUT OF THE QUESTION WITH ANY STRONGER UPDRAFTS. && .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 415 AM MDT SAT APR 18 2015 TODAY...SLOW MOVING CLOSED UPPER LOW PROGGED TO MOVE FROM CENTRAL COLORADO THIS MORNING TO EAST CENTRAL COLORADO BY DINNER TIME. ALL MODELS INCLUDING THE HRRR SHOW A BAND OF PRECIPITATION SWINGING WESTWARD ACROSS OUR COUNTIES THIS MORNING AND AFTERNOON WITH DECENT UPWARD VERTICAL MOTION AND QUASIGEOSTROPHIC FORCING...THUS HAVE OPTED TO EXTEND OUR WINTER WEATHER ADVISORIES AND WINTER STORM WARNINGS THROUGH MIDDAY...WHILE DROPPING CHEYENNE FROM THE ADVISORY WITH TEMPERATURES LIKELY REMAINING ABOVE FREEZING AND THUS MINIMAL IMPACTS TO TRAVEL. TONIGHT...FINALLY...THE UPPER TROUGH OPENS UP AS A NORTHERN STREAM SHORTWAVE TROUGH ALOFT MOVES EASTWARD INTO WESTERN NORTH DAKOTA...THUS PRECIPITATION CHANCES DWINDLE AS THE NIGHT PROGRESSES. SUNDAY...BREEZY TO WINDY...AND COOL WITH BRISK NORTHWEST FLOW ALOFT AND DEEP UNIDIRECTIONAL WINDS. LOOKS LIKE ENOUGH LOW AND MID LEVEL MOISTURE FOR ISOLATED TO SCATTERED SHOWERS OVER AND NEAR OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES...WITH MOSTLY DRY CONDITIONS ELSEWHERE. SUNDAY NIGHT...MOIST OROGRAPHIC NORTHWEST FLOW ALOFT CONTINUES PRODUCING SCATTERED TO NUMEROUS SNOW SHOWERS OVER AND NEAR OUR SNOWY...SIERRA MADRE AND LARAMIE RANGES...DRY ELSEWHERE. .LONG TERM...(MONDAY THROUGH FRIDAY) ISSUED AT 415 AM MDT SAT APR 18 2015N THE EXTENDED PERIOD WILL START OUT TRANQUIL AND THEN END POTENTIALLY UNSETTLED. NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE ON MON WITH A WEAK SHORTWAVE MOVING OVERHEAD DURING THE DAY. COULD BE SOME LIGHT SNOW SHOWERS OVER THE SIERRA MADRE AND SNOWY RANGES...BUT MUCH OF THE ACTIVITY WILL BE CONFINED TO NORTHERN COLORADO. WITH 700MB TEMPS AROUND -6C...IT WILL BE ANOTHER DAY OF BELOW NORMAL TEMPS. WE FINALLY GET TEMPS TO MODERATE SOME BY TUES AND ESPECIALLY INTO WED...BACK INTO THE 50S AND 60S TO THE EAST OF THE LARAMIE RANGE. A BUILDING SFC HIGH OVER THE NORTHERN PLAINS ON THURS WILL CAUSE SOUTHEAST WINDS TO DEVELOP ACROSS THE PLAINS. WEAK INSTABILITY WILL BE PRESENT ON THURS AFTN...SO INCLUDED A SLIGHT OF TSTMS. A SHORTWAVE WILL THEN LIFT NORTHEASTWARD FROM ARIZONA INTO COLORADO ON FRI. BOTH THE GFS AND ECMWF INDICATE THE BEST CHANCE OF WIDESPREAD PRECIP COULD BE FRI AFTN INTO FRI NIGHT WITH GOOD EASTERLY UPSLOPE FLOW OVER THE PLAINS. 700MB TEMPS ARE AROUND -2C...SO COULD BE DEALING WITH ANOTHER CASE WHERE SNOW IS LARGELY CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE. && .AVIATION...(FOR THE 18Z TAFS THROUGH SUNDAY MORNING) THE LARGE AREA OF LIGHT SNOW IS CURRENTLY ALONG AND JUST WEST OF THE LARAMIE RANGE AND MOVING SLIGHTLY WESTWARD. IFR CONDITIONS AND LIGHT SNOW WILL CONTINUE BETWEEN KRWL AND KLAR THIS AFTERNOON...WITH MVFR CONDITIONS EXPECTED AT KRWL...AND IFR CONDITIONS AT KLAR. IFR CONDITIONS DUE TO LOW CIGS WILL CONTINUE AT KCYS...BUT CONDITIONS SHOULD IMPROVE A BIT THROUGH THE AFTERNOON AS SHOWERS BEGIN TO DEVELOP TO THE SOUTH. A COLD FRONT WILL PUSH ACROSS THE PLAINS BY LATE THIS EVENING (AFTER 03Z) WITH BREEZY NORTH WINDS EXPECTED. && .FIRE WEATHER... ISSUED AT 402 AM MDT SAT APR 18 2015 NO FIRE WEATHER ISSUES WITH RECENT WIDESPREAD PRECIPITATION...AND PROJECTED HUMIDITIES AND WINDS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...WINTER STORM WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ110-114. WINTER WEATHER ADVISORY UNTIL 9 PM MDT THIS EVENING FOR WYZ103- 105-106-112-113-115. NE...NONE. && $$ UPDATE...SML SHORT TERM...RUBIN LONG TERM...ZF AVIATION...TJT FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1010 AM MDT SAT APR 18 2015 .UPDATE... ISSUED AT 1009 AM MDT SAT APR 18 2015 ADJUSTED POPS SLIGHTLY TO REFLECT THE POSITION OF THE TROWAL THIS MORNING. THE TROWAL WHICH IS VERY DISTINGUISHABLE ON SATELLITE AND RADAR WILL MOVE SLIGHTLY WESTWARD THROUGH EARLY AFTERNOON. AT THAT POINT IT WILL STALL AND THEN SHIFT EAST INTO THIS EVENING AS A NORTHERN STREAM KICKER PUSHES THE CLOSED UPPER LOW INTO THE PLAINS. LOWERED TEMPERATURES ACROSS THE WEST TODAY AS TROWAL PRECIPITATION WILL HOLD TEMPERATURES DOWN...KEEPING MOST PRECIPITATION WEST OF THE LARAMIE RANGE AS SNOW BUT SOME PLACES WILL MIX WITH OR CHANGE TO RAIN. WILL KEEP AN EYE ON THINGS BUT MAY NEED TO LOWER TEMPERATURES IN THE WEST A BIT MORE. LARAMIE SHOULD SEE SNOW THROUGH THE DAY WITH SEVERAL MORE INCHES OF SNOWFALL. WITH TEMPERATURES NEAR FREEZING AROUND LARAMIE AND THE RELATIVELY HIGH APRIL SUN ANGLE...NOT MUCH SNOW WILL ACCUMULATE ON ROADS WAYS WITH WET TO SLUSHY ROADS EXPECTED. EAST OF THE LARAMIE RANGE THERE IS THE POTENTIAL FOR THUNDERSTORMS THIS AFTERNOON. MODELS SHOWING 500-1000 J/KG OF MOST UNSTABLE CAPE. SHEAR VALUES ARE NOT IMPRESSIVE...BUT GIVEN THE COLD NATURE OF THIS SYSTEM...IT IS LIKELY THERE WILL BE SOME SMALL HAIL TODAY AND WITH LOW FREEZING LEVELS...MARGINAL SEVERE HAIL NOT OUT OF THE QUESTION WITH ANY STRONGER UPDRATS. && .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 415 AM MDT SAT APR 18 2015 TODAY...SLOW MOVING CLOSED UPPER LOW PROGGED TO MOVE FROM CENTRAL COLORADO THIS MORNING TO EAST CENTRAL COLORADO BY DINNER TIME. ALL MODELS INCLUDING THE HRRR SHOW A BAND OF PRECIPITATION SWINGING WESTWARD ACROSS OUR COUNTIES THIS MORNING AND AFTERNOON WITH DECENT UPWARD VERTICAL MOTION AND QUASIGEOSTROPHIC FORCING...THUS HAVE OPTED TO EXTEND OUR WINTER WEATHER ADVISORIES AND WINTER STORM WARNINGS THROUGH MIDDAY...WHILE DROPPING CHEYENNE FROM THE ADVISORY WITH TEMPERATURES LIKELY REMAINING ABOVE FREEZING AND THUS MINIMAL IMPACTS TO TRAVEL. TONIGHT...FINALLY...THE UPPER TROUGH OPENS UP AS A NORTHERN STREAM SHORTWAVE TROUGH ALOFT MOVES EASTWARD INTO WESTERN NORTH DAKOTA...THUS PRECIPITATION CHANCES DWINDLE AS THE NIGHT PROGRESSES. SUNDAY...BREEZY TO WINDY...AND COOL WITH BRISK NORTHWEST FLOW ALOFT AND DEEP UNIDIRECTIONAL WINDS. LOOKS LIKE ENOUGH LOW AND MID LEVEL MOISTURE FOR ISOLATED TO SCATTERED SHOWERS OVER AND NEAR OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES...WITH MOSTLY DRY CONDITIONS ELSEWHERE. SUNDAY NIGHT...MOIST OROGRAPHIC NORTHWEST FLOW ALOFT CONTINUES PRODUCING SCATTERED TO NUMEROUS SNOW SHOWERS OVER AND NEAR OUR SNOWY...SIERRA MADRE AND LARAMIE RANGES...DRY ELSEWHERE. .LONG TERM...(MONDAY THROUGH FRIDAY) ISSUED AT 415 AM MDT SAT APR 18 2015 THE EXTENDED PERIOD WILL START OUT TRANQUIL AND THEN END POTENTIALLY UNSETTLED. NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE ON MON WITH A WEAK SHORTWAVE MOVING OVERHEAD DURING THE DAY. COULD BE SOME LIGHT SNOW SHOWERS OVER THE SIERRA MADRE AND SNOWY RANGES...BUT MUCH OF THE ACTIVITY WILL BE CONFINED TO NORTHERN COLORADO. WITH 700MB TEMPS AROUND -6C...IT WILL BE ANOTHER DAY OF BELOW NORMAL TEMPS. WE FINALLY GET TEMPS TO MODERATE SOME BY TUES AND ESPECIALLY INTO WED...BACK INTO THE 50S AND 60S TO THE EAST OF THE LARAMIE RANGE. A BUILDING SFC HIGH OVER THE NORTHERN PLAINS ON THURS WILL CAUSE SOUTHEAST WINDS TO DEVELOP ACROSS THE PLAINS. WEAK INSTABILITY WILL BE PRESENT ON THURS AFTN...SO INCLUDED A SLIGHT OF TSTMS. A SHORTWAVE WILL THEN LIFT NORTHEASTWARD FROM ARIZONA INTO COLORADO ON FRI. BOTH THE GFS AND ECMWF INDICATE THE BEST CHANCE OF WIDESPREAD PRECIP COULD BE FRI AFTN INTO FRI NIGHT WITH GOOD EASTERLY UPSLOPE FLOW OVER THE PLAINS. 700MB TEMPS ARE AROUND -2C...SO COULD BE DEALING WITH ANOTHER CASE WHERE SNOW IS LARGELY CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 545 AM MDT SAT APR 18 2015 THE LARGE AREA OF LIGHT SNOW IS CURRENTLY ALONG AND JUST WEST OF THE LARAMIE RANGE AND MOVING WESTWARD. EXPECT IFR CONDITIONS AND LIGHT SNOW THROUGH MUCH OF THE MORNING TO THE WEST OF THE LARAMIE RANGE. IFR CIGS ARE EXPECTED THROUGH MID MORNING AT CYS BUT PRECIPITATION HAS ENDED. MVFR CONDITIONS WILL GENERALLY PREVAIL THROUGH 18Z OVER THE NEBRASKA PANHANDLE WITH PERIODS OF LIGHT RAIN...ESPECIALLY OVER THE NORTHERN PANHANDLE. A COLD FRONT WILL PUSH ACROSS THE PLAINS BY LATE THIS EVENING (AFTER 03Z) WITH BREEZY NORTH WINDS. && .FIRE WEATHER... ISSUED AT 402 AM MDT SAT APR 18 2015 NO FIRE WEATHER ISSUES WITH RECENT WIDESPREAD PRECIPITATION...AND PROJECTED HUMIDITIES AND WINDS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...WINTER STORM WARNING UNTIL NOON MDT TODAY FOR WYZ114>117. WINTER WEATHER ADVISORY UNTIL NOON MDT TODAY FOR WYZ103-105-106- 110-112. NE...NONE. && $$ UPDATE...SML SHORT TERM...RUBIN LONG TERM...ZF AVIATION...ZF FIRE WEATHER...RUBIN