Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/10/14


AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
445 AM PDT MON SEP 8 2014 .SYNOPSIS... MONSOONAL MOISTURE WILL REMAIN IN PLACE INTO TUESDAY WITH MAINLY AFTERNOON AND EARLY EVENING THUNDERSTORMS IN THE MOUNTAINS AND DESERTS THROUGH TUESDAY AND ALSO IN THE INLAND EMPIRE THIS AFTERNOON. DRYING WITH SEASONAL TEMPERATURES IS EXPECTED FOR WEDNESDAY INTO NEXT WEEKEND. WEAK EASTERLY MID LEVEL FLOW COULD BRING SOME MOISTURE AND AFTERNOON CLOUDS TO THE MOUNTAINS AT TIMES FROM WEDNESDAY INTO NEXT WEEKEND. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... RADAR IMAGERY SHOWS WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS DEVELOPING EARLY THIS MORNING ACROSS SOUTHERN CALIFORNIA. GENERALLY FROM THE SAN DIEGO COUNTY COASTAL WATERS ACROSS FAR NORTHERN SAN DIEGO COUNTY AND THE CENTRAL COACHELLA VALLEY NORTHWARD. THIS IS AN AREA OF DIFLUENCE AHEAD THE TROUGH OF LOW PRESSURE MOVING SOUTHWARD ALONG THE NORTHERN CALIFORNIA COAST. THE 00Z ECMWF SHOWED SOME INDICATIONS OF THIS POSSIBILITY VERSUS PREVIOUS RUNS AND THE 08Z RUN OF THE EXPERIMENTAL NCEP VERSION OF THE HRRR TAKES THE CONVECTION OVER THE NORTHERN COACHELLA VALLEY AND MOVES IT NORTHEASTWARD THIS MORNING. THE COVERAGE OF THIS ELEVATED CONVECTION IS LIMITED ENOUGH AND THE MOVEMENT TOWARD THE NORTHEAST AND EAST SUFFICIENT TO MOST LIKELY KEEP RAINFALL COVERAGE EARLY THIS MORNING LIMITED AND NOT TOO HEAVY. THE GREATEST POTENTIAL FOR LOCALLY HEAVY RAINFALL AND FLASH FLOODING EARLY THIS MORNING WILL BE OVER THE DESERTS...ESPECIALLY THE NORTHERN AND CENTRAL COACHELLA VALLEY NORTHEASTWARD. HOWEVER...WITH DAYTIME HEATING THE FOCUS IS EXPECTED TO SHIFT FARTHER INLAND FROM LATE MORNING THROUGH THE AFTERNOON AND EARLY EVENING. PRECIPITABLE WATER VALUES REMAIN NEAR 2.4 INCHES IN THE LOWER DESERTS AND 1.7 INCHES WEST OF THE MOUNTAINS. TODAY...SEA BREEZE CONVERGENCE BOUNDARIES ARE EXPECTED TO DEVELOP NEAR OR SLIGHTLY INLAND OF THE MOUNTAIN RIDGE TOPS...THEN MIGRATE INTO THE DESERTS DURING THE AFTERNOON WITH THE SEA BREEZE. THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE MOUNTAINS DURING THE LATE MORNING OR EARLY AFTERNOON...THEN MIGRATE TOWARD THE DESERTS DURING THE AFTERNOON THROUGH EARLY EVENING. THUNDERSTORMS MAY ALSO DEVELOP IN PORTIONS OF THE INLAND EMPIRE IN THE AFTERNOON ALONG THE ELSINORE CONVERGENCE ZONE. GIVEN THE HIGH MOISTURE CONTENT OF THE ATMOSPHERE AND SLOW MOVEMENT OF STORMS...THERE IS A HIGH POTENTIAL FOR HEAVY RAINFALL AND FLASH FLOODING FROM THUNDERSTORMS THIS AFTERNOON...ESPECIALLY ALONG THE EAST SLOPES OF THE MOUNTAINS AND ADJACENT DESERT AREAS. THE 06Z 4-KM VERSION OF THE NAM APPEARS TO SHOW THIS WELL. FOR LATE TONIGHT AND EARLY TUESDAY...MOISTURE FROM THE MID LEVEL REMNANTS OF FORMER HURRICANE NORBERT (NOW A POST TROPICAL LOW) WILL MOVE ACROSS NORTHERN BAJA AND FAR SOUTHERN CALIFORNIA. THE 06Z NAM DOES DEVELOP SOME PRECIPITATION LATE TONIGHT INTO EARLY TUESDAY...MAINLY IN PORTIONS OF SAN DIEGO COUNTY. WHILE DRYING WILL BE UNDERWAY ON TUESDAY...THUNDERSTORMS ARE EXPECTED DURING THE AFTERNOON OVER THE MOUNTAINS AND DESERTS...MAINLY FROM THE MOUNTAIN RIDGE TOPS INTO THE DESERTS. DECREASING MOISTURE AND A LITTLE FASTER STORM MOVEMENT SHOULD REDUCE THE POTENTIAL FOR FLASH FLOODING A LITTLE. DRIER WEATHER WITH SEASONAL TEMPERATURES WILL PREVAIL FOR WEDNESDAY INTO NEXT WEEKEND. WEAK EASTERLY MID LEVEL FLOW COULD BRING SOME MOISTURE AND AFTERNOON CLOUDS TO THE MOUNTAINS AT TIMES FROM WEDNESDAY INTO NEXT WEEKEND. && .AVIATION... 080900Z...COAST/VALLEYS...VFR CONDITIONS CONDITIONS WILL CONTINUE THROUGH THIS EVENING...WITH SCT/BKN MID AND HIGH CLOUDS. THE CLOUD DECK MAY LOWER TO BETWEEN 2000-4000 FT MSL AFT 09/0300Z. MTNS/DESERTS...VFR CONDITIONS WILL CONTINUE THROUGH THIS MORNING. HOWEVER...AFT 08/1800Z...CUMULUS WILL BEGIN TO BUILD OVER THE HIGHER TERRAIN WITH BASES AROUND 6000 FT MSL AND TOPS ABV 25000 FT MSL. ISOLATED TO SCATTERED THUNDERSTORMS WILL DEVELOP OVER THE RIDGE TOPS...EVENTUALLY PUSHING INTO THE DESERTS. THESE STORMS WILL BE CAPABLE OF PRODUCING GUSTY ERRATIC WINDS...STRONG UP/DOWNDRAFTS...REDUCED VIS FROM HEAVY RAIN AND LIGHTNING. CONDITIONS WILL IMPROVE BY THIS EVENING. && .MARINE...THERE IS NO SIGNIFICANT MARINE WEATHER EXPECTED THROUGH SATURDAY. && .BEACHES... 200 AM...ELEVATED SURF AND STRONG RIP CURRENTS WILL CONTINUE THROUGH TONIGHT DUE TO A LONG-PERIOD SOUTH SOUTHEAST SWELL. SETS TO 7 FEET WILL BE POSSIBLE...MAINLY ON SOUTHERLY FACING BEACHES. A BEACH HAZARD STATEMENT REMAINS IN EFFECT THROUGH TONIGHT. && .SKYWARN... SKYWARN ACTIVATION IS REQUESTED FOR THE LATE MORNING THROUGH EARLY EVENING TODAY FOR THE MOUNTAINS...DESERTS...AND INLAND EMPIRE. SPOTTER ACTIVATION MAY BE NEEDED AGAIN TUESDAY AFTERNOON FOR THE MOUNTAINS AND DESERTS. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR THE APPLE AND LUCERNE VALLEYS...COACHELLA VALLEY...RIVERSIDE COUNTY MOUNTAINS...SAN BERNARDINO COUNTY MOUNTAINS...SAN DIEGO COUNTY DESERTS...SAN DIEGO COUNTY MOUNTAINS. BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT FOR THE BEACHES IN THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO COUNTY COASTAL AREAS. FLASH FLOOD WATCH FROM 10 AM PDT THIS MORNING THROUGH THIS EVENING FOR THE SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE. PZ...NONE. && $$ PUBLIC...17 AVIATION/MARINE/BEACHES...JT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
341 PM MDT MON SEP 8 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 340 PM MDT MON SEP 8 2014 ...LOCALIZED FLASH FLOOD POTENTIAL ALONG THE CONTINENTAL DIVIDE TONIGHT... CONVECTION HAS BEEN SLOW TO GET GOING ACROSS THE AREA TODAY...IN PART BY CLOUD COVER OUT WEST WHICH HAS HINDERED HEATING...AND IN PART BY FALLING DEW POINTS ACROSS THE I-25 CORRIDOR AND SOUTHEAST PLAINS WHICH HAS LIMITED CAPE. LOCAL HRRR BREAKS OUT STRONGER CONVECTION ACROSS THE MOUNTAINS DURING THE LATE AFTERNOON AS WELL AS ALONG A SFC TROF AXIS ACROSS THE SOUTHEAST PLAINS. OVERALL...CAPES ARE NOT ALL THAT HIGH...SO THINK THIS CONVECTION WILL BE ON THE WEAK SIDE. HOWEVER...THERE IS SUFFICIENT MOISTURE IN THE ATMOSPHERE FOR HEAVY ENOUGH RAINFALL TO CAUSE PROBLEMS FOR BURN SCARS...PARTICULARLY OUT WEST WHERE THEY ARE STEADILY INCREASING. INTERESTINGLY...HRRR SEEMS TO BE BACKING OFF ON QPF ACROSS THE SOUTHWEST MOUNTAINS THIS AFTERNOON BUT NAM12 AND OTHER VARIOUS HIGH RES MODELS STILL SUGGEST THE THREAT IS THERE. GREATER THREAT FOR FLASH FLOODING FOR THE SOUTHWEST MOUNTAINS STILL APPEARS TO COME IN DURING THE OVERNIGHT HOURS AS THE SHORTWAVE ACROSS EAST CENTRAL AZ LIFTS SLOWING TO THE NORTHEAST INTO NRN NM OVERNIGHT. ALSO WATCHING A VERY DISCERNIBLE SHORTWAVE ACROSS WESTERN UT WHICH WILL BE MOVING ACROSS THE AREA AT THE SAME TIME THAT MONSOON MOISTURE ADVECTS INTO THE SOUTHWEST MOUNTAINS. PRECIPITABLE WATERS INCREASE TO NEAR AN INCH AT PAGOSA SPRINGS AS H7 WINDS IN THE NAM INCREASE FROM THE SOUTHWEST. THIS COMPONENT PROVIDES THE MOST FAVORABLE UPSLOPE COMPONENT INTO THE EASTERN SAN JUAN MOUNTAINS. ALL THIS SHOULD MEAN SHOWERS AND THUNDERSTORMS WILL EXPAND IN AREAL COVERAGE OVERNIGHT (AFTER 06Z) AS LIFT AND MOISTURE INCREASE WITH THE INCOMING WAVES. ALTHOUGH THE MODELS PORTRAY VARIOUS SCENARIOS AS TO WHERE THE QPF MAXIMUM WILL OCCUR...THERE ARE SUFFICIENT SIGNALS IN THE MODEL DATA TO SUGGEST A HEAVY RAINFALL POTENTIAL SIGNIFICANT ENOUGH TO WARRANT A FLASH FLOOD WATCH FOR THE EASTERN SAN JUAN MOUNTAINS WERE UPSLOPE MAY REGENERATE SHOWERS AND THUNDERSTORMS WHICH COULD TRAIN OVER THE SAME SPOTS AS THEY MOVE OFF TO THE NORTHEAST. STORM MOTIONS SHOULD BE FAST...BUT REPETITIVE RAINFALL ON THE SAME LOCATION MAY CAUSE FLASH FLOOD PROBLEMS WITH THE WEST FORK BURN SCAR BEING MOST UNDER THE GUN. REALLY CAN`T RULE OUT HEAVY RAIN ANYWHERE ACROSS WESTERN PORTIONS OF THE FORECAST AREA...BUT THREAT SEEMS HIGHEST ACROSS THE SOUTHWEST MOUNTAINS DUE TO THE UPSLOPE AND PROXIMITY TO THE BURN SCAR SO WILL LIMIT FLASH FLOOD WATCH TO THAT AREA FOR NOW. ONE WAVE OF PRECIPITATION WILL SPREAD EASTWARD ACROSS THE AREA LATE TONIGHT...WITH SCATTERED SHOWERS SPREADING INTO THE PIKES PEAK REGION TOWARDS DAWN. THIS INITIAL BATCH STILL LOOKS RATHER LIGHT AS IT MOVES EAST OF THE CONTDVD...AND QUICKLY SKIRTS OFF TO THE EAST DURING THE MORNING. THEN THE MAIN PACIFIC TROF MOVES IN DURING THE AFTERNOON. THIS SHOULD ENHANCE SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS AGAIN DURING THE AFTERNOON WHICH WILL KEEP THE THREAT FOR LOCALIZED FLASH FLOODING GOING ACROSS THE SOUTHWEST MOUNTAINS. STILL NOT STRONG ENOUGH SIGNALS TO SUGGEST FLASH FLOODING FOR THE SOUTHEAST MTS/PLAINS. LOW LEVEL WINDS ARE WESTERLY WHICH IS DOWNSLOPE...AND AS A RESULT...DEW POINTS...WHICH DO INCREASE SOME...ARE STILL ONLY IN THE 40S. THIS RESULTS IN CAPES OF ONLY A FEW HUNDRED J/KG DURING THE AFTERNOON. SHOWERS AND THUNDERSTORMS WILL MOVE OFF THE MOUNTAINS DURING THE AFTERNOON...AND WILL ALSO BECOME FOCUSED ALONG A FRONT WHICH DROPS SOUTH OF THE PALMER DIVIDE BETWEEN 21Z AND 00Z. CONVECTIVE BULLS-EYES ACROSS THE SOUTHEAST PLAINS MEANDER FROM RUN TO RUN...BUT PARAMETERS ARE NOT FAVORABLE TO PIN PRECIPITATION TO THE SOUTHEAST MOUNTAINS LONG ENOUGH TO CAUSE PROBLEMS. STORM MOTIONS WILL BE TO THE EAST AT A PRETTY GOOD CLIP. WILL KEEP MAINLY ISOLATED POPS FOR THE PLAINS DURING THE AFTERNOON...WITH POPS INCREASING INTO THE EVENING HOURS AS THE FRONT MOVES THROUGH. TEMPERATURES TONIGHT WILL BE MILD WITH INCREASING CLOUD COVER. HIGHS ON TUESDAY WILL BE COOLER OUT EAST WITH MORE WIDESPREAD PRECIPITATION. MEANWHILE...WESTERLY DOWNSLOPE WINDS WILL BATTLE CLOUD COVER AT TIMES ACROSS THE SOUTHEAST PLAINS...BUT OVERALL KEPT MAX TEMPERATURES ON THE WARM SIDE. -KT .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 340 PM MDT MON SEP 8 2014 .TUESDAY NIGHT AND WEDNESDAY...SHOWERS AND THUNDERSTORMS WILL LINGER INTO THE EVENING AS THE TROUGH PASSES THOUGH FROM THE NORTHWEST. ANY CAPE SHOULD END BY LATER IN THE EVENING AS THE COOLER MORE STABLE AIR MOVES INTO THE REGION. OVER THE MOUNTAINS...LOWER LEVEL COLD AIR WILL BE TOO SHALLOW TO PASS OVER THE EASTERN MOUNTAINS. KEPT SCATTER POPS OVER THE MOUNTAINS OVERNIGHT AND INTO WEDNESDAY MORNING AS TROUGH WILL NOT PASS THROUGH THE REGION UNTIL EARLY WEDNESDAY. ON WEDNESDAY...DRIER AIR MASS ALOFT MOVES INTO THE REGION. ON THE PLAINS...ANOTHER SURGE OF COOLER AIR MOVES INTO THE REGION BEHIND THE TROUGH. ATMOSPHERE WILL BE TOO STABLE OVER THE PLAINS DURING THE DAY. BUKFIT SOUNDINGS SUGGEST THERE MAY BE ENOUGH HEATING FOR SOME LATER AFTERNOON THUNDERSTORMS ALONG THE INTERSTATE 25 CORRIDOR AND OVER THE EASTERN MOUNTAINS. BY THE EVENING...THE COOL AIR ON THE PLAINS MAY BECOME DEEP ENOUGH TO PRODUCE SOME VERY LIGHT SHOWERS AND KEPT ISOLATED POPS IN THE GRIDS. .THURSDAY AND FRIDAY...MODELS AND ENSEMBLES AGREE ON HAVING A SHARPER TROUGH PASSING OVER THE REGION LATE THURSDAY INTO FRIDAY. EC IS SLOWER...DEEPER AND COLDER WITH THE TROUGH. EC HAS 700MB APPROACHING -4C OVER EL PASO COUNTY FRIDAY MORNING WHILE GFS IS CLOSER TO +2C. ANTICIPATE A REASONABLE CHANCE OF LIGHT RAIN THURSDAY EVENING AS THE TROUGH APPROACHES WITH THE COLD FRONTAL PASSAGE. EC SOLUTION SUGGEST A BETTER CHANCE FOR PRECIPITATION THURSDAY NIGHT. BEST CHANCES APPEAR TO BE FROM THE EASTERN MOUNTAINS AND EASTWARD ASSOCIATED WITH THE MORE MOISTURE UPSLOPE FLOW. FRIDAY HAS THE POTENTIAL TO BE A CHILLY AND CLOUDY DAY ON THE PLAINS AND EASTERN MOUNTAINS. EXTENDED PROCEDURE GAVE HIGHS IN THE 50S OVER THE PLAINS FRIDAY...WITH LOW CLOUDS LINGERING UNTIL AT LEAST MID AFTERNOON. DEPENDING ON THE SPEED OF THE SYSTEM AND THE AMOUNT OF CLOUDINESS...HIGH TEMPERATURES COULD EVEN BE COOLER. LOW LEVEL COLD AIR MASS WILL MOSTLY STAY EAST ALONG AND EAST OF THE EASTERN MOUNTAINS. WITH WARMING AND DRYING ALOFT...IT COULD BE A SUNNY AND MILD DAY OVER THE REMAINING MOUNTAINS AND HIGH VALLEYS. .SATURDAY THROUGH MONDAY...WILL HAVE TO WATCH FOR THE POTENTIAL OF SOME FROST SATURDAY MORNING...DEPENDING ON THE AMOUNT OF CLEARING. AFTERWARDS...A WARMING TREND WILL DEVELOP FOR THE WEEKEND ESPECIALLY OVER THE PLAINS AND EASTERN MOUNTAINS AS THE SURFACE HIGH MOVES EAST OF THE REGION. SOME MONSOON MOISTURE COULD MOVE INTO THE MOUNTAINS OVER THE WEEKEND...AND INCREASED POPS SLIGHTLY. OVER THE PLAINS...LOW LEVEL MOISTURE WILL RETURN ON SUNDAY AND MONDAY...AND THE INCREASED MOISTURE COULD RESULT IN A FEW AFTERNOON AND EVENING STORMS. --PGW-- && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 340 PM MDT MON SEP 8 2014 SHOWERS AND THUNDERSTORMS WILL CONTINUE TO INCREASE ACROSS THE REGION TONIGHT...PARTICULARLY ALONG THE CONTINENTAL DIVIDE WHERE WIDESPREAD MTN OBSCURATIONS WILL DEVELOP AFTER MIDNIGHT. KALS...KCOS...AND KPUB WILL CONTINUE TO SEE VFR CIGS AT TIMES WITH SHOWERS AND THUNDERSTORMS POSSIBLE LATE THIS AFTERNOON IN THE VCNTY OF THE AIRPORTS...THEN AGAIN TOWARDS TUESDAY MORNING AS A DISTURBANCE MOVES ACROSS THE REGION. SOME CLEARING WILL TAKE PLACE DURING THE LATE MORNING AND EARLY AFTERNOON BEFORE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ROLLS OFF THE MOUNTAINS DURING THE AFTERNOON. THESE TOO MAY PRODUCE VFR TO LOCAL MVFR CIGS/VIS AS THEY MOVE ACROSS THE REGION. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH TUESDAY AFTERNOON FOR COZ067-068. && $$ SHORT TERM...KT LONG TERM...PGW AVIATION...KT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1057 AM MDT MON SEP 8 2014 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 411 AM MDT MON SEP 8 2014 MODEL DATA CONTINUES TO SHOW EXCELLENT CONTINUITY REGARDING THE INTERACTION OF UPPER TROUGH ALONG THE CALIFORNIA COAST AND MOISTURE PLUME (WHICH INCLUDES THE REMAINS OF NORBERT). MOISTURE PLUME ARCS FROM THE LOWER COLORADO RIVER BASIN INTO SW UTAH... EVENTUALLY SPREADING EAST INTO WRN COLORADO AS THE DAY PROGRESSES TODAY. IN THE SHORT TERM OUTLOOK...THE HRRR SHOWS THE AREA OF PCPN OVER PARTS OF SW COLORADO (OR WRN PORTION OF THE SAN JUAN MOUNTAINS) WILL SHIFT NORTHWARD EARLY THIS MORNING AND BE POSITIONED OVER THE I70 CORRIDOR AROUND DAYBREAK. HAVE NOT SEEN THIS NORTHWARD TREND YET...BUT SEEMS REASONABLE AS ISENTROPIC UPGLIDE AND INCREASING MOISTURE FROM THE WEST ACCOUNTS FOR AN INCREASING CHANCE OF RAIN. SPECIFIC HUMIDITIES AT 700 MB IS QUITE HIGH WITH VALUES RANGING FROM 8 TO 10 G/KG. PRECIPITABLE WATER AT KGJT IS PROGGED TO BE 1.25 INCHES BY 00Z THIS EVENING (PER RAP13)... WHICH IS PLUS 3 STANDARD DEVIATIONS ABOVE NORMAL. USED THE DAY 1 EXCESSIVE RAINFALL OUTLOOK TO FINE TUNE THE FLASH FLOOD WATCH. THE ONLY AREAS OUTSIDE THE EXCESSIVE RAINFALL IS PARTS OF NE UTAH...WRN MOFFAT COUNTY AND ARCHULETA COUNTY AND THE ERN EDGE OF OUR FORECAST AREA. TONIGHT DEEP MOISTURE CONTINUES TO ADVECT IN FROM THE SW UP TO 1.3 INCHES IN SE UTAH AND EVEN UP TO 1.6 INCHES IN THE 00Z NAM12. THIS IS VERY HIGH FOR EARLY SEPTEMBER...GREATER THAN TWO STANDARD DEVIATIONS ABOVE NORMAL. THE SATURATED VERTICAL PROFILE WITH WET BULB ZERO/ICE PRODUCTION LEVEL AROUND 10KFT WILL NOT NEED DEEP CONVECTIVE CELLS TO PRODUCE HEAVY RAINFALL. SO THIS WILL MAKE THE RADAR OBSERVATIONS DIFFICULT TO CAPTURE SOME OF THE HEAVIEST SHOWERS OCCURRING IN THE FOUR CORNERS REGION. STORM MOTION WILL BE QUICK THOUGH TO THE ENE AT 20KTS INCREASING TO 30 KTS BY EARLY TUESDAY MORNING. SOME SHOWERS WILL BE MIXING THESE WINDS DOWN TO THE SURFACE. THIS IS NOT CAPTURED WELL IN MOS GUIDANCE. TUESDAY THE BROAD TROUGH WORKS THROUGH THE GREAT BASIN AND INTO THIS CWA BY LATE AFTERNOON. GRADIENT WINDS VEERS FROM SW TO W AND INCREASE TO 30 TO 50 KTS IN THE 0-6KM LAYER. THIS WEST FLOW WILL BEGIN TO ERODE MOISTURE IN THE MID LEVELS ADDING TO AFTERNOON INSTABILITY. PRECIP WATER VALUES FALL BELOW ONE INCH IN THE AFTERNOON. JET SUPPORT PASSES THROUGH WYOMING BUT POTENTIAL VORT FIELDS SHOW SOME FORCING ACROSS THE NORTH. SO CHANCES FOR STRONGER CONVECTIVE CELLS INCREASE TUESDAY AFTERNOON ESPECIALLY OVER THE NORTH. GUSTY WINDS AND SMALL HAIL ARE POSSIBLE. HEAVIER RAIN SHOWERS PERSIST IN THE SOUTH. EXPECT A COOL DAY UNDER WIDESPREAD CLOUDS AND SHOWERS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 411 AM MDT MON SEP 8 2014 TUESDAY NIGHT...WITH TROUGH PASSAGE OVERNIGHT THE FLOW VEERS TO A DRIER NW AND PRECIP WATER VALUES DROP TO AROUND 0.5 INCHES FOR ALL BUT THE SOUTHERN MOST ZONES. SHOWERS ARE EXPECTED TO ERODE FROM WEST TO EAST THROUGH THE EVENING. THERE MAY BE SOME THREAT OF LOCALIZED MORNING FOG. WEDNESDAY-WEDNESDAY NIGHT...A FEW AFTERNOON SHOWERS MAY FORM IN THE EASTERN MOUNTAINS WEDNESDAY AFTERNOON IN RESIDUAL MOISTURE. OTHERWISE PLENTY OF SUN RETURNS TO THE FORECAST AREA. TEMPERATURES REMAIN BELOW NORMAL. LIGHT WINDS AND CLEARING SKIES WEDNESDAY NIGHT SHOULD ALLOW FOR MODERATE TO STRONG SURFACE BASED INVERSIONS AND COOL OVERNIGHT LOW TEMPERATURES. THURSDAY THROUGH SUNDAY...DRY AND STABLE NORTHWEST FLOW IS EXPECTED TO PREVAIL THROUGH THIS PERIOD. RIDGE AXIS AMPLIFIES OVER THE WRN STATES WITH TIME. AFTERNOON TEMPS WILL HAVE RECOVERED FROM THE RAIN COOLED AIR MASS WITH PLENTY OF DAYTIME SUNSHINE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1055 AM MDT MON SEP 8 2014 MOISTURE CONTINUES TO STREAM INTO EASTERN UTAH AND WESTERN COLORADO THIS MORNING. LIFT HAS BEEN UNFOCUSED WITH MAINLY ISOLATED TO SCATTERED SHOWERS DRIFTING THROUGH WITH MINIMAL IMPACTS TO FORECAST TERMINALS. HEATING OF THE DAY WILL HELP BOOST CONVECTION THIS AFTERNOON AND THE SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD. OVERALL LIFT INCREASES OVERNIGHT INTO TUESDAY LEAVING NUMEROUS SHOWERS AND THUNDERSTORMS IN PLACE ACROSS THE REGION. THEREFOR TERMINAL FORECASTS WILL BE OPTIMISTIC IN THE FIRST 6 TO 12 HOURS...THEN BECOME INCREASING PESSIMISTIC WITH BETTER CHANCES OF IFR/MVFR CONDITIONS. OBSCURATION OF THE HIGHER TERRAIN WILL ALSO BECOME WIDESPREAD THIS AFTERNOON THROUGH TOMORROW EVENING BEFORE DRYING MOVES IN BEHIND THIS SYSTEM. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR COZ002>014-017>022. UT...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR UTZ022-025-027>029. && $$ SHORT TERM...PF/JOE LONG TERM...JOE/PF AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
517 AM MDT MON SEP 8 2014 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 411 AM MDT MON SEP 8 2014 MODEL DATA CONTINUES TO SHOW EXCELLENT CONTINUITY REGARDING THE INTERACTION OF UPPER TROUGH ALONG THE CALIFORNIA COAST AND MOISTURE PLUME (WHICH INCLUDES THE REMAINS OF NORBERT). MOISTURE PLUME ARCS FROM THE LOWER COLORADO RIVER BASIN INTO SW UTAH... EVENTUALLY SPREADING EAST INTO WRN COLORADO AS THE DAY PROGRESSES TODAY. IN THE SHORT TERM OUTLOOK...THE HRRR SHOWS THE AREA OF PCPN OVER PARTS OF SW COLORADO (OR WRN PORTION OF THE SAN JUAN MOUNTAINS) WILL SHIFT NORTHWARD EARLY THIS MORNING AND BE POSITIONED OVER THE I70 CORRIDOR AROUND DAYBREAK. HAVE NOT SEEN THIS NORTHWARD TREND YET...BUT SEEMS REASONABLE AS ISENTROPIC UPGLIDE AND INCREASING MOISTURE FROM THE WEST ACCOUNTS FOR AN INCREASING CHANCE OF RAIN. SPECIFIC HUMIDITIES AT 700 MB IS QUITE HIGH WITH VALUES RANGING FROM 8 TO 10 G/KG. PRECIPITABLE WATER AT KGJT IS PROGGED TO BE 1.25 INCHES BY 00Z THIS EVENING (PER RAP13)... WHICH IS PLUS 3 STANDARD DEVIATIONS ABOVE NORMAL. USED THE DAY 1 EXCESSIVE RAINFALL OUTLOOK TO FINE TUNE THE FLASH FLOOD WATCH. THE ONLY AREAS OUTSIDE THE EXCESSIVE RAINFALL IS PARTS OF NE UTAH...WRN MOFFAT COUNTY AND ARCHULETA COUNTY AND THE ERN EDGE OF OUR FORECAST AREA. TONIGHT DEEP MOISTURE CONTINUES TO ADVECT IN FROM THE SW UP TO 1.3 INCHES IN SE UTAH AND EVEN UP TO 1.6 INCHES IN THE 00Z NAM12. THIS IS VERY HIGH FOR EARLY SEPTEMBER...GREATER THAN TWO STANDARD DEVIATIONS ABOVE NORMAL. THE SATURATED VERTICAL PROFILE WITH WET BULB ZERO/ICE PRODUCTION LEVEL AROUND 10KFT WILL NOT NEED DEEP CONVECTIVE CELLS TO PRODUCE HEAVY RAINFALL. SO THIS WILL MAKE THE RADAR OBSERVATIONS DIFFICULT TO CAPTURE SOME OF THE HEAVIEST SHOWERS OCCURRING IN THE FOUR CORNERS REGION. STORM MOTION WILL BE QUICK THOUGH TO THE ENE AT 20KTS INCREASING TO 30 KTS BY EARLY TUESDAY MORNING. SOME SHOWERS WILL BE MIXING THESE WINDS DOWN TO THE SURFACE. THIS IS NOT CAPTURED WELL IN MOS GUIDANCE. TUESDAY THE BROAD TROUGH WORKS THROUGH THE GREAT BASIN AND INTO THIS CWA BY LATE AFTERNOON. GRADIENT WINDS VEERS FROM SW TO W AND INCREASE TO 30 TO 50 KTS IN THE 0-6KM LAYER. THIS WEST FLOW WILL BEGIN TO ERODE MOISTURE IN THE MID LEVELS ADDING TO AFTERNOON INSTABILITY. PRECIP WATER VALUES FALL BELOW ONE INCH IN THE AFTERNOON. JET SUPPORT PASSES THROUGH WYOMING BUT POTENTIAL VORT FIELDS SHOW SOME FORCING ACROSS THE NORTH. SO CHANCES FOR STRONGER CONVECTIVE CELLS INCREASE TUESDAY AFTERNOON ESPECIALLY OVER THE NORTH. GUSTY WINDS AND SMALL HAIL ARE POSSIBLE. HEAVIER RAIN SHOWERS PERSIST IN THE SOUTH. EXPECT A COOL DAY UNDER WIDESPREAD CLOUDS AND SHOWERS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 411 AM MDT MON SEP 8 2014 TUESDAY NIGHT...WITH TROUGH PASSAGE OVERNIGHT THE FLOW VEERS TO A DRIER NW AND PRECIP WATER VALUES DROP TO AROUND 0.5 INCHES FOR ALL BUT THE SOUTHERN MOST ZONES. SHOWERS ARE EXPECTED TO ERODE FROM WEST TO EAST THROUGH THE EVENING. THERE MAY BE SOME THREAT OF LOCALIZED MORNING FOG. WEDNESDAY-WEDNESDAY NIGHT...A FEW AFTERNOON SHOWERS MAY FORM IN THE EASTERN MOUNTAINS WEDNESDAY AFTERNOON IN RESIDUAL MOISTURE. OTHERWISE PLENTY OF SUN RETURNS TO THE FORECAST AREA. TEMPERATURES REMAIN BELOW NORMAL. LIGHT WINDS AND CLEARING SKIES WEDNESDAY NIGHT SHOULD ALLOW FOR MODERATE TO STRONG SURFACE BASED INVERSIONS AND COOL OVERNIGHT LOW TEMPERATURES. THURSDAY THROUGH SUNDAY...DRY AND STABLE NORTHWEST FLOW IS EXPECTED TO PREVAIL THROUGH THIS PERIOD. RIDGE AXIS AMPLIFIES OVER THE WRN STATES WITH TIME. AFTERNOON TEMPS WILL HAVE RECOVERED FROM THE RAIN COOLDED AIR MASS WITH PLENTY OF DAYTIME SUNSHINE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 517 AM MDT MON SEP 8 2014 DETERIORATING CONDITIONS TODAY AS SCATTERED -SHRA/-TSRA WILL EXPAND IN AREAL COVERAL TODAY AND BECOME NUMEROUS THIS AFTERNOON. FREQUEST -SHRA WITH EMBEDDED -TSRA IS EXPECTED TONIGHT WITH LOCAL 4SM +SHRA POSSIBLE. CIGS/VIS MAY LOWER TO IFR/MVFR FROM THE STRONGEST SHOWERS OR THUNDERSTORMS...ESPECIALLY AT MOUNTAIN TAF SITES. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...FLASH FLOOD WATCH FROM 9 AM MDT THIS MORNING THROUGH TUESDAY EVENING FOR COZ002>014-017>022. UT...FLASH FLOOD WATCH FROM 9 AM MDT THIS MORNING THROUGH TUESDAY EVENING FOR UTZ022-025-027>029. && $$ SHORT TERM...PF/JOE LONG TERM...JOE/PF AVIATION...PF
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
411 AM MDT MON SEP 8 2014 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 411 AM MDT MON SEP 8 2014 MODEL DATA CONTINUES TO SHOW EXCELLENT CONTINUITY REGARDING THE INTERACTION OF UPPER TROUGH ALONG THE CALIFORNIA COAST AND MOISTURE PLUME (WHICH INCLUDES THE REMAINS OF NORBERT). MOISTURE PLUME ARCS FROM THE LOWER COLORADO RIVER BASIN INTO SW UTAH... EVENTUALLY SPREADING EAST INTO WRN COLORADO AS THE DAY PROGRESSES TODAY. IN THE SHORT TERM OUTLOOK...THE HRRR SHOWS THE AREA OF PCPN OVER PARTS OF SW COLORADO (OR WRN PORTION OF THE SAN JUAN MOUNTAINS) WILL SHIFT NORTHWARD EARLY THIS MORNING AND BE POSITIONED OVER THE I70 CORRIDOR AROUND DAYBREAK. HAVE NOT SEEN THIS NORTHWARD TREND YET...BUT SEEMS REASONABLE AS ISENTROPIC UPGLIDE AND INCREASING MOISTURE FROM THE WEST ACCOUNTS FOR AN INCREASING CHANCE OF RAIN. SPECIFIC HUMIDITIES AT 700 MB IS QUITE HIGH WITH VALUES RANGING FROM 8 TO 10 G/KG. PRECIPITABLE WATER AT KGJT IS PROGGED TO BE 1.25 INCHES BY 00Z THIS EVENING (PER RAP13)... WHICH IS PLUS 3 STANDARD DEVIATIONS ABOVE NORMAL. USED THE DAY 1 EXCESSIVE RAINFALL OUTLOOK TO FINE TUNE THE FLASH FLOOD WATCH. THE ONLY AREAS OUTSIDE THE EXCESSIVE RAINFALL IS PARTS OF NE UTAH...WRN MOFFAT COUNTY AND ARCHULETA COUNTY AND THE ERN EDGE OF OUR FORECAST AREA. TONIGHT DEEP MOISTURE CONTINUES TO ADVECT IN FROM THE SW UP TO 1.3 INCHES IN SE UTAH AND EVEN UP TO 1.6 INCHES IN THE 00Z NAM12. THIS IS VERY HIGH FOR EARLY SEPTEMBER...GREATER THAN TWO STANDARD DEVIATIONS ABOVE NORMAL. THE SATURATED VERTICAL PROFILE WITH WET BULB ZERO/ICE PRODUCTION LEVEL AROUND 10KFT WILL NOT NEED DEEP CONVECTIVE CELLS TO PRODUCE HEAVY RAINFALL. SO THIS WILL MAKE THE RADAR OBSERVATIONS DIFFICULT TO CAPTURE SOME OF THE HEAVIEST SHOWERS OCCURRING IN THE FOUR CORNERS REGION. STORM MOTION WILL BE QUICK THOUGH TO THE ENE AT 20KTS INCREASING TO 30 KTS BY EARLY TUESDAY MORNING. SOME SHOWERS WILL BE MIXING THESE WINDS DOWN TO THE SURFACE. THIS IS NOT CAPTURED WELL IN MOS GUIDANCE. TUESDAY THE BROAD TROUGH WORKS THROUGH THE GREAT BASIN AND INTO THIS CWA BY LATE AFTERNOON. GRADIENT WINDS VEERS FROM SW TO W AND INCREASE TO 30 TO 50 KTS IN THE 0-6KM LAYER. THIS WEST FLOW WILL BEGIN TO ERODE MOISTURE IN THE MID LEVELS ADDING TO AFTERNOON INSTABILITY. PRECIP WATER VALUES FALL BELOW ONE INCH IN THE AFTERNOON. JET SUPPORT PASSES THROUGH WYOMING BUT POTENTIAL VORT FIELDS SHOW SOME FORCING ACROSS THE NORTH. SO CHANCES FOR STRONGER CONVECTIVE CELLS INCREASE TUESDAY AFTERNOON ESPECIALLY OVER THE NORTH. GUSTY WINDS AND SMALL HAIL ARE POSSIBLE. HEAVIER RAIN SHOWERS PERSIST IN THE SOUTH. EXPECT A COOL DAY UNDER WIDESPREAD CLOUDS AND SHOWERS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 411 AM MDT MON SEP 8 2014 TUESDAY NIGHT...WITH TROUGH PASSAGE OVERNIGHT THE FLOW VEERS TO A DRIER NW AND PRECIP WATER VALUES DROP TO AROUND 0.5 INCHES FOR ALL BUT THE SOUTHERN MOST ZONES. SHOWERS ARE EXPECTED TO ERODE FROM WEST TO EAST THROUGH THE EVENING. THERE MAY BE SOME THREAT OF LOCALIZED MORNING FOG. WEDNESDAY-WEDNESDAY NIGHT...A FEW AFTERNOON SHOWERS MAY FORM IN THE EASTERN MOUNTAINS WEDNESDAY AFTERNOON IN RESIDUAL MOISTURE. OTHERWISE PLENTY OF SUN RETURNS TO THE FORECAST AREA. TEMPERATURES REMAIN BELOW NORMAL. LIGHT WINDS AND CLEARING SKIES WEDNESDAY NIGHT SHOULD ALLOW FOR MODERATE TO STRONG SURFACE BASED INVERSIONS AND COOL OVERNIGHT LOW TEMPERATURES. THURSDAY THROUGH SUNDAY...DRY AND STABLE NORTHWEST FLOW IS EXPECTED TO PREVAIL THROUGH THIS PERIOD. RIDGE AXIS AMPLIFIES OVER THE WRN STATES WITH TIME. AFTERNOON TEMPS WILL HAVE RECOVERED FROM THE RAIN COOLDED AIR MASS WITH PLENTY OF DAYTIME SUNSHINE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 102 4 PM MDT SUN SEP 7 2014 AN AREA OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUES TO DRIFT SLOWLY EAST FROM ABAJO MOUNTAINS THROUGH MOST OF SOUTHWESTERN COLORADO. THIS AREA OF SHOWERS WILL DIMINISH AFTER MIDNIGHT. AN ISOLATED SHOWER/THUNDERSTORM WILL STILL BE POSSIBLE INTO THE MORNING HOURS ON MONDAY. AS MOISTURE INCREASES FROM THE SOUTH ON MONDAY THE THREAT OF SHOWERS AND THUNDERSTORMS WILL PUSH INTO THE SCATTERED CATEGORIES BY MONDAY AFTERNOON WITH MORE WIDESPREAD COVERAGE BY MONDAY NIGHT. AT THE ONSET...GUSTY OUTFLOW WINDS TO 45 MPH WILL BE POSSIBLE. LOCALLY HEAVY RAIN WILL RESULT IN SCT MVFR CONDITIONS WITH ISOLATED IFR WHICH WILL CONTINUE AND INCREASE IN COVERAGE BY MONDAY NIGHT. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...FLASH FLOOD WATCH FROM 9 AM MDT THIS MORNING THROUGH TUESDAY EVENING FOR COZ002>014-017>022. UT...FLASH FLOOD WATCH FROM 9 AM MDT THIS MORNING THROUGH TUESDAY EVENING FOR UTZ022-025-027>029. && $$ SHORT TERM...PF/JOE LONG TERM...JOE/PF AVIATION...MPM
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
930 PM EDT TUE SEP 9 2014 .SYNOPSIS... AN ONSHORE FLOW PRODUCED BY THE COMBINED EFFECTS OF HIGH PRESSURE EAST OF THE CANADIAN MARITIMES AND LOW PRESSURE OFF THE MID ATLANTIC COAST WILL GRADUALLY WEAKEN ON WEDNESDAY AS BOTH SYSTEMS MOVE FURTHER OFFSHORE. A COLD FRONT WILL MOVE THROUGH THE AREA THURSDAY NIGHT, THEN STALL TO OUR SOUTH WHILE HIGH PRESSURE BUILDS IN FROM THE NORTH ON FRIDAY. THE STALLED BOUNDARY COULD WORK ITS WAY BACK NORTH SATURDAY, THEN OFFSHORE LATE IN THE WEEKEND. HIGH PRESSURE IS THEN EXPECTED TO BUILD INTO THE MID-ATLANTIC REGION BY MONDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 930 PM UPDATE...NOT TOO MANY CHANGES AS THE TEMPERATURE FORECAST STILL LOOKS ON TRACK. HOWEVER, GIVEN THE RADAR TRENDS OVER THE LAST SEVERAL HOURS, DID LOWER THE PRECIP CHANCES, TO ONLY AN ISOLATED SHOWER MENTION ON THE COASTAL PLAINS. PREVIOUS NEAR TERM DISCUSSION...A LOW PRESSURE SYSTEM WILL CONTINUE TO MOVE NORTHEAST OFFSHORE TONIGHT. EXPECT A RATHER CLOUDY NIGHT ACROSS THE REGION OVERALL WHICH MAY KEEP LOW TEMPERATURES IN THE 60`S FOR MOST OF THE REGION. COOLER TEMPERATURES WILL BE OBSERVED NW OF PHL. STAYED CLOSE TO MAV/MET GUIDANCE WITH TEMPS AND DEWPOINTS. SOME ISOLATED SHOWERS ARE PRESENT ACROSS THE EASTERN PORTIONS OF THE REGION AND WILL MOVE FROM EAST TO WEST THROUGH THE REMAINDER OF THE AFTERNOON. SLIGHT CHANCE POPS IN PLACE, BASICALLY FROM PHL TO THE SE. THE RAP SHOWS THE POTENTIAL FOR SOME ADDITIONAL SCATTERED SHOWERS TO MOVE CLOSE TO THE COAST TONIGHT AND A SLIGHT TO LOW CHANCE POP HAS BEEN LEFT IN THE FORECAST TO ACCOUNT FOR THIS. LIGHT QPF UNDER 1/10TH INCH IS EXPECTED, WITH RFC FORECAST QPF GUIDANCE USED OVERNIGHT AND THE EARLY EVENING QPF FORECAST BASED MORE ON THE SREF. CONTINUED NORTHEAST WINDS TONIGHT PERHAPS A FEW GUSTS EARLY AROUND 20 MPH. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... THE LOW PRESSURE SYSTEM WILL CONTINUE MOVING OFFSHORE ON WEDNESDAY. THIS WILL ALLOW CLOUDS TO GRADUALLY CLEAR BY THE END OF THE DAY AND ANY REMAINING POPS ARE BEFORE NOON ALONG THE SHORE. WINDS WILL SHIFT AROUND TO THE SOUTHEAST AHEAD OF THE NEXT SYSTEM, GENERALLY UNDER 10 MPH. WITH THE CLOUD COVER HIGH TEMPERATURES MAY BE HELD DOWN A BIT, SO DID NOT GO THE WARMER MET GUIDANCE. FORECASTED TEMPERATURES TREND MORE TOWARD THE COOLER MAV GUIDANCE, RIGHT AROUND 80 FOR PHL AND 70`S FOR MOST. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... AS THE COASTAL LOW CONTINUES TO MOVE FURTHER OFFSHORE...WEAK HIGH PRESSURE WILL BUILD IN WEDNESDAY NIGHT AND THURSDAY AS A COLD FRONT APPROACHES FROM THE WEST. THE LATEST GFS RUN INDICATES THIS NEXT COLD FRONT MIGHT ENTER OUR FAR WESTERN ZONES LATE THURSDAY AFTERNOON...PASSING THROUGH THE REST OF THE CWA DURING THE EVENING HOURS BEFORE REACHING THE COAST AROUND MIDNIGHT. THIS LATEST RUN ALSO INDICATES THE FRONT MIGHT STALL A LITTLE FURTHER SOUTH OF OUR AREA COMPARED TO EARLIER RUNS WHICH COULD TRANSLATE INTO A MOSTLY PRECIPITATION-FREE WEEKEND AS HIGH PRESSURE MOVING THROUGH THE GREAT LAKES BUILDS OVER THE REGION. THE ECMWF IS NOT AS OPTIMISTIC AND KEEPS THE FRONT CLOSER TO OUR AREA, ALONG WITH A PROLONGED THREAT OF SHOWER ACTIVITY FOR THE WEEKEND. IN TERMS OF THE FORECAST GRIDS...AFTERNOON POPS ON THURSDAY ARE HIGHEST IN THE PA ZONES, WHERE TIMING OF FROPA WOULD COINCIDE MORE FAVORABLY WITH PEAK HEATING HOURS. THERE IS SOME DEGREE OF A THREAT FOR HEAVY RAINFALL IN THUNDERSTORMS, BUT THE THREAT OF MAY BE MORE LOCALIZED THAN WIDESPREAD. THEN POPS BECOME PROGRESSIVELY HIGHER FROM WEST TO EAST AS THE FRONT MOVES THROUGH. A BASICALLY RAIN FREE PERIOD IS EXPECTED LATER FRIDAY INTO EARLY SATURDAY, BUT SHOWERS COULD RETURN ONCE AGAIN SATURDAY AFTERNOON INTO SUNDAY DEPENDING ON WHERE THE STALLED FRONT ACTUALLY SETS UP SHOP. POPS THAT WERE ALREADY INTRODUCED INTO THE GRIDS WERE BASICALLY KEPT IN THIS FCST CYCLE UNTIL MODEL INFORMATION BECOMES MORE CERTAIN. IMPROVEMENTS ARE EXPECTED EARLY NEXT WEEK AS HIGH PRESSURE MOVES IN FROM THE NORTHWEST. IN TERMS OF TEMPERATURES...ABOVE NORMAL EXPECTED UNTIL THE FRONT MOVES THROUGH THURSDAY NIGHT...THEN NEAR TO SLIGHTLY BELOW NORMAL AFTER THAT. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. FOR THE 00Z TAFS...EXPECT MVFR CEILINGS TO MOVE IN ACROSS MUCH OF THE REGION BY 09Z. CEILINGS COULD BE VRB AT TIMES, BUT IN GENERAL SHOULD BE MVFR FOR MUCH OF THE NIGHT INTO TOMORROW MORNING AS THE PERSISTENT ON SHORE FLOW CONTINUES. FOR LOCATIONS CLOSER TO THE COAST, INCLUDING KACY AND KMIV, IFR CEILINGS ARE POSSIBLE MOSTLY BETWEEN 09 AND 15Z. THERE IS ALSO A CHANCE FOR LOWER VISIBILITIES OVERNIGHT AS THE LOW LEVELS WILL BE NEARLY SATURATED IN MANY PLACES. HOWEVER, WINDS SHOULD STAY ABOVE 5KT, AND NEAR 10KT IN MANY PLACES, THIS SHOULD INHIBIT DENSE FOG DEVELOPMENT. THUS...ONLY EXPECT VISIBILITIES TO LOWER TO THE 3 TO 5SM RANGE. CEILINGS SHOULD SLOWLY RISE, AND POSSIBLY DISSIPATE BETWEEN 15 AND 18Z TOMORROW. AS WITH THE OVERNIGHT HOURS, TERMINALS CLOSER TO THE COAST (KACY AND KMIV) SHOULD SEE THE LOWER CONDITIONS LONGER. OUTLOOK... WEDNESDAY NIGHT...VFR IN THE EVE. LOW CLOUDS AND FOG MAY DEVELOP OVERNIGHT. THURSDAY AND THURSDAY NIGHT...SHRA AND TSRA LIKELY IN THE AFTN AT RDG/ABE. THIS ACTIVITY MAY HOLD OFF FARTHER EAST UNTIL THE EVE WHEN A COLD FRONT MOVES THRU. FROPA WILL BE MARKED BY WIND SHIFT FROM S TO NW. FRIDAY AND FRIDAY NIGHT...VFR SATURDAY AND SUNDAY...CHANCE OF SHRA WITH SUB-VFR CONDITIONS POSSIBLE. && .MARINE... SEAS ARE CURRENTLY RUNNING WELL OVER FIVE FEET ON THE OCEAN WATERS. WITH THE CONTINUED ONSHORE FLOW SEAS WILL LIKELY BE OVER FIVE FEET THROUGH WEDNESDAY. AS A RESULT, THE SMALL CRAFT ADVISORY HAS BEEN EXTENDED THROUGH WEDNESDAY NIGHT ON THE OCEAN WATERS. WINDS AROUND 20 KNOTS ARE LIKELY WITH THE POTENTIAL FOR SCA CRITERIA GUSTS THROUGH TONIGHT AND INTO WEDNESDAY MORNING ON THE OCEAN WATERS. FOR DELAWARE BAY, WINDS HAVE GENERALLY BEEN AT OR UNDER 20 KNOTS AND WITH LOWER SEAS ONGOING. WE`LL ALLOW THE SCA TO EXPIRE AT 6PM ON THE BAY. OUTLOOK... WEDNESDAY NIGHT...THE PRESSURE GRADIENT GRADUALLY WEAKENS AND WINDS SHOULD DECREASE TO BELOW SCA LEVELS BY THE AFTN. HOWEVER, THE SCA MAY STILL BE NEEDED AS SEAS WILL TAKE TIME TO SUBSIDE. THE LATEST GUIDANCE SUGGESTS WAVES OF 4-5 FT FOR THIS PERIOD. THURSDAY...SOUTHERLY WINDS INCREASE AHEAD OF A FRONT BUT SHOULD REMAIN BELOW SCA LVLS. THURSDAY NIGHT AND FRIDAY MORNING...COLD FRONT MOVES THRU THE WATERS THURSDAY NIGHT. STORMS MAY PRODUCE LOCALLY GUSTY WINDS JUST AHEAD OF THE FRONT DURING THE EVE. PRESSURE SURGE IN WAKE OF FROPA MAY PRODUCE A BRIEF PERIOD OF NW WINDS GUSTING TO NEAR SCA THRESHOLD LATE THURSDAY NIGHT INTO FRIDAY MORNING. FRIDAY AFTERNOON THROUGH SUNDAY....NO MARINE HEADLINES ARE EXPECTED. && .TIDES/COASTAL FLOODING... WITH A COASTAL LOW MEANDERING JUST OFFSHORE AND ONSHORE FLOW CONTINUING, THE THREAT OF MINOR COASTAL FLOODING IS EXPECTED TO CONTINUE INTO AT LEAST WEDNESDAY MORNING`S HIGH TIDE CYCLE. MINOR TIDAL FLOODING IS ALREADY OCCURRING ON THE OCEAN FRONT NOW AND SHOULD BEGIN ON THE LOWER DELAWARE BAY SOON. GOING INTO WEDNESDAY MORNING AND MIDDAY, THE PRESSURE GRADIENT ALONG THE COAST LOOKS TO TIGHTEN SOMEWHAT, AND THE WINDS ARE FORECAST TO BECOME A LITTLE MORE NORTHEASTERLY. WE THEREFORE HAVE EXTENDED THE CURRENT COASTAL FLOOD ADVISORY THROUGH THE WEDNESDAY MORNING TO MIDDAY HIGH TIDE CYCLE. && .RIP CURRENTS... THE THREAT FOR RIP CURRENTS ON WEDNESDAY IS EXPECTED TO BE AT LEAST MODERATE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...COASTAL FLOOD ADVISORY UNTIL 2 PM EDT WEDNESDAY FOR NJZ012>014- 020-022>027. COASTAL FLOOD ADVISORY UNTIL 4 PM EDT WEDNESDAY FOR NJZ016-021. DE...COASTAL FLOOD ADVISORY UNTIL 2 PM EDT WEDNESDAY FOR DEZ003-004. COASTAL FLOOD ADVISORY UNTIL 4 PM EDT WEDNESDAY FOR DEZ001-002. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT WEDNESDAY NIGHT FOR ANZ450>455. && $$ SYNOPSIS...MIKETTA NEAR TERM...GAINES/JOHNSON/NIERENBERG SHORT TERM...GAINES/NIERENBERG LONG TERM...MIKETTA AVIATION...JOHNSON/MIKETTA MARINE...GAINES/NIERENBERG/MIKETTA TIDES/COASTAL FLOODING...KLINE/JOHNSON RIP CURRENTS...JOHNSON
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
917 AM EDT MON SEP 8 2014 .SYNOPSIS... HIGH PRESSURE OVER NEW ENGLAND WILL STRENGTHEN AS IT MOVES TO THE MARITIMES TONIGHT. MEANWHILE LOW PRESSURE WILL BE MOVING SLOWLY NORTHEAST FROM THE COASTAL CAROLINAS AND PASSING OUT TO SEA EAST OF THE MID ATLANTIC COAST WEDNESDAY NIGHT OR THURSDAY. A COLD FRONT WILL CROSS OUR AREA FROM THE NORTHWEST LATE THURSDAY OR FRIDAY. STRONG HIGH PRESSURE OVER THE PLAINS STATES FRIDAY BUILDS INTO THE NORTHEAST FOR THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... BASED ON LATEST RADAR AND HRRR GUID HAVE REMOVED POPS ACRS THE LWR DELMARVA IN THE REAL NEAR TERM AND LOWERED POPS A TAD LATER TODAY. WILL SEE HOW THINGS DEVELOP FOR THE LATE MRNG UPDATE. OTHERWISE, ADJUSTED CLOUD COVER DOWNWARD UP NORTH, WHERE STLT IMAGERY SHOWED IT WAS CLEAR. WEAK LOW PRESSURE DEVELOPING OFF THE SE US COAST TODAY AND PERSISTENT HIGH PRESSURE ACROSS ERN NEW ENGLAND AND SE CANADA WILL KEEP A ONSHORE FLOW DIRECTED ACROSS OUR AREA TODAY. HIGH/MID LEVEL CLOUDINESS ALREADY EXISTS ACROSS THE S/E HALF OF THE AREA...AND IT WILL CONTINUE TO LOWER/THICKEN TODAY. WITH REGARDS TO PCPN POTENTIAL...WE HAVE SIDED A BIT CLOSER TO THE GFS WHICH BRINGS SOME SMALL CHC FOR SHOWERS TO THE DELMARVA LATER TODAY...OVERALL OUR POPS ARE A BIT LESS THAN THE PREVIOUS FCST. THE 00Z EC HAS SOME LIGHTER SHOWERS DEVELOPING FURTHER NORTH AND EARLIER THAN THE GFS...BUT THIS DOES NOT LOOK RIGHT...SO WE WILL KEEP THE IDEAS FROM THE THE EARLIER FCST...JUST SLOWED DOWN A BIT. TEMPS...MOSTLY MAV BUT BLENDED IN WITH EARLIER FCST TOO. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... MUCH LIKE THE NEAR TERM...HIGHER PCPN CHC ESPECIALLY S/E WHERE LIKELY/LOW CATEGORICAL POPS ARE EXPECTED...NO PCPN EXPECTED N/W. WEAK LOW WILL SLIDE A BIT UP THE COAST AND KEEP THE ONSHORE FLOW ACROSS THE AREA...CLOUDS ARE EXPECTED ACROSS MOST ALL AREAS...LESS N/W. WINDS MOSTLY ERLY AROUND 10 KTS. && .LONG TERM /TUESDAY THROUGH SUNDAY/... AN AMENDED-CORRECTED SET OF ZONES WAS SENT AT 510AM TO MORE ACCURATELY ACCOUNT FOR THE GRIDDED 330 AM FORECAST EXPECTATIONS BETWEEN TUESDAY AND SATURDAY. 500 MB: A SLOW MOVING TROUGH MOVES EAST ACROSS THE MID ATLANTIC STATES TUESDAY AND WEDNESDAY. THEREAFTER...TWO STRONG SHORT WAVES MOVE THROUGH THE UPPER MIDWEST FROM LATE THURSDAY THROUGH NEXT SUNDAY. TEMPERATURES: THE FIRST WEEK OF SEPTEMBER HAS AVERAGED WELL ABOVE NORMAL...ON THE ORDER OF ABOUT 6 DEGREES. NEAR NORMAL TEMPERATURES TUESDAY SHOULD WARM TO MORE THAN 5 DEGREES ABOVE NORMAL THURSDAY THEN COOL TO SLIGHTLY BELOW NORMAL OVER THE WEEKEND. FORECAST BASIS: UNLESS OTHERWISE NOTED THE LONG TERM PERIOD OF THIS FORECAST IS GENERALLY BASED ON A 50 50 BLEND OF THE 00Z/8 NAM/GFS MOS FOR THE PERIOD TUESDAY - WEDNESDAY...THE 00Z/8 GFS MOS WEDNESDAY NIGHT AND THURSDAY...THEN THEREAFTER (THURSDAY NIGHT ONWARD) THE 0443Z/8 WPC GRIDDED GUIDANCE WHICH AT TIMES IS BLENDED 50 50 WITH THE 00Z/8 MEXMOS. ALL THIS IS EVENTUALLY CHECKED AGAINST THE 00Z/8 ECMWF TO SEE IF WE`RE IN THE BALLPARK WITH ECMWF CYCLICALLY PERSISTENT 18Z 2 METER TEMPERATURES. THE PRECIPITATION PROBABILITY GUIDANCE IS CHECKED AGAINST THE 21Z/7 SREF 3HRLY POPS FOR .01 THROUGH 12Z THURSDAY AND THEREAFTER THE 00Z/8 GEFS 6HR POPS FOR 0.05 THE DAILIES BELOW... TUESDAY INTO WEDNESDAY...IT MAY BE NASTY AT TIMES ALONG THE DE COAST AND THE S NJ COAST WITH GUSTY EAST NORTHEAST WINDS AND BANDS OF SHOWERS SWEEPING NWWD INLAND IN A TROWAL ENVIRONMENT. POTENTIAL 6 TO 8 FOOT SURF ALONG PORTIONS OF THE COAST. THERE IS STILL UNCERTAINTY AS TO HOW MUCH RAIN WILL ACCUMULATE IN OUR AREA. THERE IS A GOOD CHANCE THE REGION NORTH OF INTERSTATE 78 (NE PA AND NW NJ) RECEIVES ONLY A TRACE OF SPRINKLES OR NO RAIN AT ALL WHILE AMOUNTS SOMEWHERE IN SOUTHERN DELAWARE MIGHT BE QUITE SUBSTANTIAL. HIGH TEMPERATURES WILL BE DEPENDENT ON DURATION OF ANY RAIN DURING THE MIDDAY AND AFTN HOURS WITH WET BULBING POSSIBLY MEANING HIGHS ONLY NEAR 70. ISOLATED THUNDER MAY OCCUR IN DE AND COASTAL S NJ. LATER WEDNESDAY INTO THURSDAY...A DISTINCTLY RAINFREE PERIOD AS THE COASTAL LOW TURNS EAST OUT TO SEA AND A COLD FRONT WITH WARM AIR ADVECTION AHEAD OF IT AND THEN EVENTUALLY A SLIVER OF INSTABILITY ALONG IT ARRIVES FOR THURSDAY NIGHT. SO A VERY NICE WARMUP IS ANTICIPATED FOR THURSDAY (15-16C AT 850MB) AND THIS SHOULD BE THE WARMEST DAY OF THE WORK WEEK...MID 80S ANTICIPATED. SHOWERS AND THUNDERSTORMS MAY OCCUR VERY LATE IN THE DAY OR AT NIGHT. WHAT HAPPENS FRIDAY INTO EARLY SATURDAY IS HIGHLY UNCERTAIN AS MODELS...ESPECIALLY THE ECMWF HAVE BEEN FLIP FLOPPING. IT APPEARS THAT THERE IS A POSSIBLE STALLING OR SLOWING OF THE COLD FRONTAL PASSAGE SO THAT SHOWERS NEED TO REMAIN IN THE FORECAST. VERY LOW CONFIDENCE ON WHAT WILL OCCUR FOR THIS TIME FRAME OF THE FORECAST. THE OP EC IS AT ODDS WITH THE GEFS. LATER SATURDAY AND SUNDAY...HIGH PRESSURE IS EXPECTED TO FOLLOW THE COLD FRONTS SEAWARD PASSAGE. IT WILL BE A TYPICAL EARLY AUTUMN AIR MASS...SEASONABLY COOLER...WITH HIGHS MAINLY IN THE 70S AND LOWS MOSTLY IN THE 50S. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THERE WERE NOT MANY CHANGES IN THE 06Z TAFS...COMPARED TO THE 00Z TAFS. THE TRENDS IN THE OPERATIONAL MODELS REMAIN ABOUT THE SAME. HIGH/MID LEVEL CLOUDINESS INCREASE OVER THE AREA...FOLLOWED BY LOWER CLOUDS LATER THIS AFTERNOON AND TONIGHT...ESPECIALLY SOUTH/EAST. WE HAVE VFR CONDITIONS IN THE TERMINALS EVERYWHERE THRU 06Z TUE...WITH SOME MVFR FOR THE 30 HT PHL TAF COVERING THE 06Z-12Z TUE PERIOD. WINDS WILL INCREASE FROM THE NE/E TODAY AND REMAIN AROUND 10 KNOTS TONIGHT. CLOSER TO THE COAST WINDS WILL BE 5 TO 10 KTS HIGHER WITH SOME GUSTINESS POSSIBLE. OUTLOOK... TUESDAY...VFR CIGS OCNLLY MVFR CONDITIONS IN SCATTERED SHOWERS. BRIEF IFR CONDS POSSIBLE VCNTY KMIV AND KACY IN HEAVIER SHOWERS. EAST TO NORTHEAST GUSTS 18-28 KT. CONFIDENCE: AVERAGE WEDNESDAY...MAINLY VFR WITH ANY LINGERING SHOWERS TENDING TO END FROM WEST TO EAST. CONFIDENCE: AVERAGE. WEDNESDAY NIGHT AND THURSDAY...VFR EXCEPT FOR LATE NIGHT AND EARLY MORNING LOW CLOUDS AND FOG. THERE IS ALSO A CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS WITH MVFR AND IFR CONDITIONS POSSIBLE AT TIMES. CONFIDENCE: AVERAGE. THURSDAY NIGHT...A CHANCE OF SHOWERS AND THUNDERSTORMS WITH MVFR AND IFR CONDITIONS POSSIBLE AT TIMES. CONFIDENCE: AVERAGE. FRIDAY...MAINLY VFR BUT CONFIDENCE IS WELL BELOW AVERAGE SINCE A MVFR OR EVEN IFR CONDITION SCENARIO COULD DEVELOP IF THE PROJECTED COLD FRONTAL PASSAGE STALLS IN OUR AREA FOR 12 HOURS. && .MARINE... WE WILL CONTINUE WITH SCA FLAGS FOR THE WATERS TODAY...WE WILL DELAY THE ONSET TIME A FEW HOURS THAN EARLIER SET. WINDS/SEAS EXPECTED TO SLOWLY INCREASE TODAY AND SEAS ON THE OCEAN SHOULD BUILD TO 5 TO 7 FT BY TONIGHT. SCA CONDITIONS LOOK TO PERSIST SEVERAL PERIODS. OUTLOOK... TUESDAY...A SMALL CRAFT ADVISORY IS IN EFFECT FOR A BRISK EAST-NORTHEASTERLY FLOW AND SEAS ABOVE 5 FT. TUESDAY NIGHT AND WEDNESDAY...SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED TO CONTINUE, ESPECIALLY ON OUR OCEAN WATERS. WE DID NOT EXTEND THE ADVISORY AT THIS TIME SINCE WE FIRST WANT TO BE SURE WE REACH ADVISORY CONDITION TODAY. WEDNESDAY NIGHT...WIND SPEEDS ARE FORECAST TO FALL BELOW THE SMALL CRAFT ADVISORY CRITERION. HOWEVER, WAVES ON OUR OCEAN WATERS MAY REMAIN AROUND 5 FEET. THURSDAY THROUGH FRIDAY...NO MARINE HEADLINES ARE ANTICIPATED ALTHOUGH THERE MAY BE A SHORT WINDOW OF SMALL CRAFT ADVISORY CONDITIONS FRIDAY? && .TIDES/COASTAL FLOODING... THE ONSHORE FLOW WILL INCREASE TODAY AND REMAIN IN PLACE THE NEXT SEVERAL DAYS. TIDAL DEPARTURES WILL INCREASE...BUT THE DEGREE OF DEPARTURE REMAINS UNCERTAIN. THE HIGHER OF THE TOW TIDES THIS EVENING WILL PROBABLY BE AROUND MINOR TIDAL FLOODING LEVELS...PERHAPS A BIT OVER. WE LOOK TO FALL IN THE RANGE OF...PROBABLY NOT ENOUGH OVER FOR STATEMENTS TO BE ISSUED...SO WE WILL GO THIS ROUTE FOR NOW. STAY TUNED FOR UPDATES LATER TODAY. THE EAST-NORTHEAST FLOW IS EXPECTED TO CONTINUE DURING THE SUBSEQUENT TWO TO FOUR HIGH TIDE CYCLES FOR TUE-WED AND IT MAY CAUSE ADDITIONAL MINOR TIDAL FLOODING IN SOME AREAS. THE PHILADELPHIA AREA WILL REMAIN HIGHLIGHTED ON THE WWA POINT AND CLICK MAP BUT IT IS LEAST LIKELY TO EXCEED THE MINOR COASTAL FLOOD THRESHOLD...DUE TO THE NORTHEAST FLOW. WAVE RUNUP ALONG THE ATLANTIC SHORES MAY ADD LOCALLY TO THE INUNDATION IMPACT....ESPECIALLY TUESDAY. ADDITIONALLY...BEACH EROSION MAY OCCUR. && .RIP CURRENTS... AN INCREASING NORTHEASTERLY FLOW, COMBINED WITH THE FULL MOON AND BUILDING WAVES IN THE SURF ZONE, RESULTS IN A MODERATE RISK OF DANGEROUS RIP CURRENTS TODAY. A MODERATE TO STRONG NORTHEASTERLY FLOW CONTINUES TUESDAY AND WEDNESDAY CREATING AT LEAST A MODERATE RISK FOR THE FORMATION OF DANGEROUS RIP CURRENTS. SURF SHOULD BUILD TO AT LEAST 5 FEET THIS AFTERNOON... 6 TO POSSIBLY 8 FEET TUESDAY AND WEDNESDAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT TUESDAY FOR ANZ431-452>455. SMALL CRAFT ADVISORY UNTIL 6 PM EDT TUESDAY FOR ANZ430-450-451. && $$ SYNOPSIS...DRAG NEAR TERM...NIERENBERG/O`HARA SHORT TERM...O`HARA LONG TERM...DRAG AVIATION...DRAG/O`HARA MARINE...DRAG/O`HARA TIDES/COASTAL FLOODING... RIP CURRENTS...
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1015 PM EDT TUE SEP 9 2014 .DISCUSSION... CONVECTIVE LINE FIRED ALONG THE I-4 CORRIDOR ARND SUNSET WITH CELLS PRODUCING LCL HEAVY RAIN...RADAR ESTIMATED PRECIP BTWN 2.5"-3.0" IN CENTRAL SEMINOLE COUNTY...KSFB MEASURED 1.35" IN A LITTLE OVER AN HOUR. BULK OF THE PRECIP HAS BURNED ITSELF OUT...LINGERING LIGHT RAIN N OF I-4 WILL DISSIPATE BEFORE MIDNIGHT. EVENING RAOBS SHOW DEEP MOISTURE ACRS THE FL PENINSULA WITH PWAT VALUES RANGING FROM 2.0"-2.2". RUC ANALYSIS SHOWS INCREASING LOW LVL MOISTURE UPSTREAM WITH H100-H70 MEAN RH VALUES 80-90PCT OVER THE NRN BAHAMAS. HOWEVER...DYNAMIC SUPPORT IS LACKING WITH NO ORGANIZED H85-H50 VORT MAXES AND A CONVERGENT H30-H20 LYR. H85-H70 LAPSE RATES BTWN 6.5-7.0C/KM REMAIN STEEP ENOUGH TO KEEP THUNDER IN OVERNIGHT... BUT VALUES DROP BLO 5.0C/KM THRU THE H70-H50 LYR...LEAVING DEEP LYR INSTABILITY MODEST AT BEST. MINOR ADJUSTMENTS TO THE TIMING OF COASTAL SHRAS/TSRAS OVERNIGHT... OTHERWISE FCST IS IN GOOD SHAPE. && .AVIATION... THRU 10/14Z...E/SE SFC WINDS AOB 5KTS...PREVAILING VFR WITH BRIEF MVFR CSTL SHRAS S OF KTIX. BTWN 09/14Z-09/16Z...SFC WNDS BCMG E ARND 10KTS...SLGT CHC MVFR SHRAS/IFR TSRAS CSTL SITES. AFT 16Z...CHC MVFR SHRAS/IFR TSRAS INTERIOR SITES...SLGT CHC CSTL SITES. && .MARINE... WEAK ATLC RIDGE AXIS OVER N FL WILL GENERATE A LIGHT TO GENTLE ERLY BREEZE ACRS THE LCL ATLC OVERNIGHT. ISOLD SHRAS WILL FORM S OF THE CAPE IN THE WAKE EDDIES OF THE NRN BAHAMAS...BUT LITTLE IN THE WAY OF MID/UPR LVL SUPPORT WILL LIMIT THEIR IMPACT TO BRIEF PDS OF MODERATE TO HEAVY RAIN...MAINLY OVER THE GULF STREAM. SEAS 2-3FT WITH DOMINANT PDS ARND 5SEC. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ FORECAST/AVIATION...BRAGAW RADAR/IMPACT WX.....PENDERGRAST
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
202 AM EDT MON SEP 8 2014 .PREV DISCUSSION... /ISSUED 823 PM EDT SUN SEP 7 2014/ UPDATE... STALLED FRONTAL BOUNDARY REMAINS ACROSS CENTRAL GA THIS EVENING. A WAVE OF LOW PRESSURE WILL SLOWLY MOVE EAST ALONG THE BOUNDARY OVERNIGHT. NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE FOR THE NEXT FEW HOURS...BUT SHOULD BEGIN TO DIMINISH BY MIDNIGHT. DON`T EXPECT SHRA/TSRA TO COMPLETELY DIMINISH SO HAVE KEPT ISO/SCT POPS IN FOR THE ENTIRE OVERNIGHT PERIOD. IN LOCALES WHERE IT RAINED...LOW CLOUDS AND PATCHY FOG ARE POSSIBLE TOWARDS SUNRISE. HAVE TRIED TO ORIENT POPS ACCORDING TO RADAR TRENDS. THE 19Z RUN OF THE HRRR PEGGED THE CONVECTION PRETTY WELL...SO ALSO FOLLOWED SUIT. TEMPS LOOKED GOOD. PREV DISCUSSION... /ISSUED 735 PM EDT SUN SEP 7 2014/ PREV DISCUSSION... /ISSUED 308 PM EDT SUN SEP 7 2014/ SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... MODELS IN GOOD AGREEMENT TAKING THE SURFACE LOW OVER SOUTHEAST GA AND MOVING IT UP THE COAST. THIS WILL KEEP A NORTHEAST SURFACE FLOW OVER THE CWA THROUGH MONDAY NIGHT. CURRENT CONVECTION OVER THE CWA WILL DISSIPATE THIS EVENING. THERE COULD BE AN ISOLATED SHOWER/TSTORM JUST ABOUT ANYWHERE TONIGHT AND WILL MAINTAIN A 20 POP ACROSS MOST OF THE CWA. A LITTLE HIGHER POPS ACROSS THE EXTREME SOUTHEAST PART OF THE CWA TONIGHT DUE TO THE PROXIMITY OF THE SURFACE LOW. AS THE SURFACE LOW PULLS TO OUR NORTHEAST...SLIGHTLY DRIER AIR WILL MOVE INTO NORTH GA WITH THE DEEPEST MOISTURE SHIFTING TO PARTS OF CENTRAL GEORGIA AND THIS IS WHERE THE HIGHEST POPS WILL BE MONDAY AFTERNOON. ANY CONVECTION THAT DOES FORM WILL DIMINISH MONDAY NIGHT. 17 LONG TERM /TUESDAY THROUGH SUNDAY/... A WEAKENING FRONT ACROSS SOUTH GA AND A WEAK WEDGE PERSIST ACROSS NORTHEAST GA ON TUESDAY. FOR THE REMAINDER OF THE WEEK...UPPER LEVEL HIGH PRESSURE RETURNS ACROSS THE SOUTHEAST U.S. AND GA REMAINS IN A MOIST TROPICAL AIR MASS. THIS WOULD SUPPORT ISOLATED OR SCATTERED THUNDERSTORMS EACH DAY WITH MOSTLY A DIURNAL PATTERN. BY FRIDAY A FRONT GETS PUSHED INTO NORTH GA AS A BROAD UPPER TROUGH DEEPENS INTO THE GREAT LAKES. THE FRONT CONTINUES TO SINK SOUTH ON SATURDAY...HOWEVER THE ECMWF SEEMS A BIT SLOWER WITH THIS. OVERALL...IT LOOKS LIKE THERE WILL BE SOME DRYING ACROSS THE NORTH BY THE END OF THE PERIOD. HAVE SHOWN ONLY A SLIGHT CHANCE OF POPS ACROSS THE NORTH FOR SATURDAY...CHANCE ELSEWHERE. 41/16 && .AVIATION... 06Z UPDATE... LATE NIGHT STORMS CONTINUE TO WEAKEN AND DIMINISH ACROSS THE ATL METRO AREA. EXPECT IFR-MVFR CIGS TO DEVELOP BY 10Z AND SLOWLY IMPROVE AFTER 13Z TODAY. CONVECTION WILL ONCE AGAIN FIRE AFTER 16Z...WITH BEST CHANCES 18-22Z...AND GENERALLY SOUTH OF THE ATL- AHN LINE. FOR NOW HAVE GONE WITH THE PROB30 FOR ALL SITES...BUT ONLY THE SOUTHERN SITES MAY HAVE THE TEMPO COME THE 12Z ISSUANCE. EXPECT VRB WINDS AND LOW VFR CIGS WITH STORMS...AND PERIODS OF HEAVY RAINFALL WILL REDUCE VSBYS. WINDS WILL GENERALLY BE EASTERLY AT 8 KT OR LESS. //ATL CONFIDENCE...06Z UPDATE... HIGH CONFIDENCE ON ALL ELEMENTS EXCEPT FOR MEDIUM ON CIGS 10-14Z. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 84 66 87 67 / 30 20 20 20 ATLANTA 85 68 86 70 / 30 20 20 10 BLAIRSVILLE 81 62 83 62 / 40 20 20 20 CARTERSVILLE 87 67 88 68 / 30 20 20 10 COLUMBUS 89 71 90 71 / 60 30 30 10 GAINESVILLE 84 66 85 68 / 30 20 20 20 MACON 88 69 90 69 / 50 30 20 20 ROME 89 67 89 67 / 30 20 20 10 PEACHTREE CITY 86 66 87 67 / 40 20 20 10 VIDALIA 87 70 88 71 / 60 40 40 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM... AVIATION...
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
909 PM CDT TUE SEP 9 2014 .DISCUSSION... 900 PM CDT HEAVY RAINFALL CONTINUES TO BE THE MAIN CONCERN GOING THROUGH TONIGHT. SURFACE LOW PRESSURE REMAINS STRETCHED FROM THE TEXAS PANHANDLE TO NORTHWEST MISSOURI WITH A STATIONARY BOUNDARY FROM EXTREME SOUTHEAST NEBRASKA ACROSS NORTHERN MISSOURI AND ARCHING SOUTHWARD INTO SOUTHERN ILLINOIS. AN UPPER WAVE MOVING EAST INTO SOUTHWEST IOWA AND STRENGTHENING LOW LEVEL FLOW HAVE BEEN TRIGGERING A LARGE AMOUNT OF CONVECTION ACROSS SOUTHEAST NEBRASKA AND SOUTHERN IOWA WITH A COMPLEX TRACKING EAST ACROSS THE CENTRAL IA/MO BORDER. AN MCV APPEARS TO HAVE DEVELOPED WITH THIS CONVECTION ACROSS CENTRAL IOWA. A LARGER AREA OF LESS INTENSE RAINFALL CONTINUES TO SPREAD NORTHEAST FROM EASTWARD IOWA...WHERE COVERAGE IS GREATEST...TO MUCH OF WEST CENTRAL ILLINOIS THANKS TO AN INFLUX OF DEEPER MOISTURE. THE SURFACE LOW IS EXPECTED TO CONSOLIDATE OVER SOUTHWEST IOWA AND TRACK NORTHEAST INTO WEDNESDAY MORNING. THE STATIONARY FRONTAL BOUNDARY IS FORECAST TO LIFT NORTHWARD BUT THE AMOUNT OF CONVECTION OUT THERE NOW MAY SUPPRESS ITS MOVEMENT INTO THE OVERNIGHT. HOWEVER...THE STRENGTHENING SYNOPTIC FLOW SHOULD OVERCOME THIS AT SOME POINT. THE MCV CURRENTLY ACROSS CENTRAL IOWA IS EXPECTED TO TRACK EAST-NORTHEAST OVERNIGHT BRINGING CONTINUED CONVECTION WITH IT WHILE THE INCREASING LOW LEVEL JET CONTINUES TO PRODUCE CONVECTION CLOSER TO THE IA/MO BORDER IN PROXIMITY TO THE STALLED FRONT...LEADING TO A MORE EAST TO WEST ORIENTED BAND OF STORMS AT LEAST FOR A TIME INTO THE EARLY OVERNIGHT. THE LIGHTER SHOWERS AND EMBEDDED STORMS AHEAD OF THIS BETTER ORGANIZED ACTIVITY WILL CONTINUE TO SPREAD INTO THE CWA INTO THE OVERNIGHT WITH THE HEAVIER RAINFALL WITH THE MCV AND UPPER WAVE ARRIVING IN THE WEST LATER TONIGHT. THIS HEAVIER PRECIP WILL THEN TRACK ACROSS THE CENTRAL AND EASTERN CWA THROUGH THE MORNING. AT THIS POINT THE MAIN SEVERE POTENTIAL OVERNIGHT WOULD BE CLOSER TO THE FRONT TO THE SOUTHWEST BUT THE EVOLVING MCV COMPLEX MAY LEAD TO BETTER COLD POOL DEVELOPMENT WHICH MAY SPELL A WIND THREAT LATER TONIGHT IF AN ORGANIZED COMPLEX RESULTS. WILL CONTINUE WITH THE FLASH FLOOD WATCH AND MAKE REFINEMENTS TO POPS...THOUGH THE BIGGEST CHANGE WILL LIKELY BE TO TIMING DETAILS. IN ADDITION...THE SURFACE LOW SEEMS TO BE AIMING FOR A TRACK A BIT FURTHER SOUTH TAKING IT ACROSS CENTRAL INSTEAD OF NORTHERN LAKE MICHIGAN. THIS MAY RESULT IN SLIGHTLY STRONGER SYNOPTIC WINDS WEDNESDAY MORNING AND EARLY AFTERNOON...WITH CONVECTION BEING A POTENTIAL LIMITING FACTOR IN REACHING MAX WIND POTENTIAL. MDB && .PREV DISCUSSION... 335 PM CDT SHORT TERM...TONIGHT THROUGH FRIDAY... MAIN CONCERNS FOR THE FORECAST PERIOD REMAIN THUNDERSTORMS AND HEAVY RAINFALL ASSOCIATED WITH AN UNUSUALLY STRONG LATE SUMMER COLD FRONT AND UPPER TROUGH IMPACTING THE REGION FROM LATE TONIGHT INTO WEDNESDAY EVENING. THEN... FOLLOWING THE PASSAGE OF THIS SYSTEM... THE FOCUS WILL SHIFT TO THE TEMPERATURE FORECAST AND THE FIRST REAL TASTE OF AUTUMNAL WEATHER FOR LATER THIS WEEK. FOR THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING...CONDITIONS WILL BE THE RELATIVE CALM BEFORE THE STORM. THE SFC LOW IS BEGINNING TO DEEPEN OVER THE CNTRL PLAINS WHILE HIGH PRESSURE MOVES OFF THE EAST COAST. INCREASING SOUTHERLY FLOW IS RAMPING UP OVER THE LOWER AND MIDDLE MISSISSIPPI VALLEY...SETTING UP VERY STRONG WARM/MOIST ADVECTION POINTING INTO THE MIDWEST. THIS AFTERNOON...CONVECTIVE ACTIVITY HAS ALREADY BROKEN OUT ALONG THE NOSE OF A 50 KT LOW LEVEL JET...EXTENDING FROM WRN IOWA INTO CNTRL IL. THIS STRONG LOW LEVEL JET WILL CONTINUE TO PUMP MOISTURE INTO THE REGION WHILE MOISTURE ASSOCIATED WITH THE REMNANTS OF HURRICANE NORBERT ADVECT OVER THE REGION AT THE MID LEVELS. THE MODELS HAVE BEEN VERY CONSISTENT ON ADVERTISING A SWATH OF PWATS OF 2.0 TO 2.5 INCHES POOLING AHEAD OF THE FRONT. THE LOW LEVEL WARM ADVECTION AHEAD OF THE FRONT...CONVERGENCE ALONG THE FRONT...A STRONG MID LEVEL SHORTWAVE AND A COUPLED JET ALOFT WILL ALL COMBINE TO GENERATE STRONG AND PERSISTENT THUNDERSTORMS. THERE SHOULD BE ADEQUATE SHEAR IN THE LOW LEVELS BETWEEN SLY SFC WINDS AND 50 KT SWLY WINDS AT 925-850MB TO SUPPORT AN INITIAL CONVECTIVE MODE SUPPORTING SOME ISOLATED SUPERCELLS ALONG WITH THE GENERAL THUNDER. SPC HAS OUTLOOKED THE ENTIRE CWA WITH A SLIGHT RISK OVER SEVERE THUNDERSTORMS...WITH THE PRIMARY THREATS BEING STRONG DAMAGING WINDS AND MARGINALLY SEVERE HAIL. THE 12Z SOUNDINGS FROM ILX/DVN INDICATE THE FREEZING LEVEL AT 13KFT AND WITH PERSISTENT WARM ADVECTION AHEAD OF THE COLD FRONT...THE FREEZING LEVEL WILL LIKELY RISE SOME UNTIL THE FROPA. SO...WHILE THE ENVIRONMENT SHOULD SUPPORT SOME STRONG ROTATING UPDRAFTS SUFFICIENT FOR LARGE HAIL...THE HIGH FREEZING LEVELS SHOULD GIVE AMPLE TIME FOR SOME MELTING. AS FOR THE WIND THREAT...WITH THE STRONG LOW LEVEL JET POINTING OVER THE AREA...STRONG WINDS SHOULD BE ABLE TO MIX DOWN...PARTICULARLY IN THE WARM SECTOR AHEAD OF THE FRONT WHERE SURFACE BASED CONVECTION SHOULD BE ABLE TO FORM. SO...STRONG...DAMAGING WINDS WILL BE A CONCERN DURING THE INITIAL THUNDERSTORM DEVELOPMENT LATE THIS EVENING. HEAVY RAINFALL... THROUGH THE NIGHT...CONVECTIVE MODE WILL TRANSITION OVER TO MORE LINES OR CLUSTERS...AND EVENTUALLY CONGEALING INTO A LARGE AREA OF THUNDERSTORMS. WITH FLOW ABOVE THE BOUNDARY LEVEL TO ABOUT 700MB SWLY...AND WLY-WNWLY JET-LEVEL WINDS...CELL MOVEMENT WITHIN THE OVERALL THUNDERSTORM AREA WILL BE TO THE NORTHEAST WHILE THE LARGER SCALE PATTERN IS SLOWLY PROGRESSIVE TO THE EAST. SO...ANTICIPATE THAT THERE SHOULD BE AMPLE OPPORTUNITY FOR REPEATED DEVELOPMENT OR TRAINING OF STORMS. ALL ELEMENTS ARE COMING TOGETHER FOR A SIGNIFICANT HEAVY RAIN EVENT. STORMS WILL BE EFFICIENT RAIN PRODUCERS GIVEN THE DEEP LAYER MOISTURE AND RAINFALL RATES OF 2 TO 3 INCHES PER HOUR FROM SOME STORMS WILL NOT BE OUT OF THE QUESTION. FORTUNATELY...THE PATTERN WILL BE SLOWLY...BUT STEADILY PROGRESSIVE...SO RAINFALL WILL BE WIDESPREAD RATHER THAN CONFINED TO A SMALL AREA. LATEST THINKING IS THAT STORM TOTAL QPF SHOULD BE ARND 2.0 TO 2.5 INCHES. IN AREAS OF TRAINING OR REPEATED STORM DEVELOPMENT...LOCALIZED AREAS OF 3 TO 5 INCHES TOTAL RAINFALL WILL BE POSSIBLE. THE MOST FAVORED TIMING FOR THE STRONGEST STORMS WILL BE LATE THIS EVENING AND OVERNIGHT. THERE MAY BE A BRIEF LULL IN ACTIVITY DURG THE MORNING HOURS...HOWEVER...EXPECT ANOTHER UPTICK IN ACTIVITY DURG THE LATE MORNING/EARLY AFTERNOON AS THE COLD FRONT PUSHES THROUGH NWRN INDIANA. MAJOR CHANGE IN AIRMASS... FOLLOWING THE FRONTAL PASSAGE WEDNESDAY AFTERNOON AND EVENING...LOW WILL TURN NWLY TO NLY BEHIND THE FRONT. WEAK CYCLONIC CURVATURE AND COLD ADVECTION WILL BRING SOME INSTABILITY SHOWERS IN THE COLDER AIR BEHIND THE FRONT...THROUGH THURSDAY...A BROAD UPPER TROUGH WILL CARVE OUT OVER THE CNTRL CONUS. A SERIES OF NORTHERN STREAM SHORTWAVES WILL HELP INCREASE THE AMPLITUDE OF THE UPPER TROUGH WHILE SUPPLYING MUCH COOLER AIR TO THE REGION. BY THURSDAY MORNING...TEMPERATURES SHOULD DROP OFF INTO THE MIDDLE 40S OVER THE NWRN PORTION OF THE CWA...INCLUDING THE ROCKFORD METRO AREA. SOUTHEAST OF A LINE FROM CHICAGO TO PONTIAC...LOWS THURSDAY MORNING SHOULD REMAIN IN THE LOWER TO MIDDLE 50S. TEMPERATURES WILL NOT HAVE MUCH OPPORTUNITY FOR DIURNAL WARMING THROUGH THE DAY GIVEN THE PERSISTENT COLD ADVECTION...WITH HIGHS THURSDAY ONLY IN THE LOWER TO MIDDLE 60S. THERE IS EVEN A CHANCE THAT THE ROCKFORD AREA MAY NOT BE ABLE TO GET OUT OF THE UPPER 50S. BY FRIDAY MORNING... TEMPERATURES IN THE LOWER TO MIDDLE 40S WILL COVE THE WHOLE CWA...AWAY FROM THE URBANIZED PORTION OF THE CHICAGO METRO AREA. FOR FRIDAY...MAX TEMPS SHOULD BE EVEN LOWER THAN THURSDAY...WITH NCNTRL/NWRN IL REMAINING IN THE MIDDLE 50S WHILE NERN IL/NWRN IN SHOULD SEE TEMPS LOW OUT IN THE LOW 60S. KREIN LONG TERM...FRIDAY NIGHT THROUGH TUESDAY... THE BIG STORY IN THE EXTENDED PERIOD IS THE REINFORCING SHOT OF UNSEASONABLY COOL AIR THAT WILL BRING EARLY TO MID OCTOBER TEMPERATURES OVER THE WEEKEND. IN RESPONSE TO PERSISTENT HIGH AMPLITUDE RIDGING ALONG THE WEST COAST UP TO ALASKA...A DEEP MEAN TROUGH WILL LOCK IN OVER THE EASTERN HALF OF CANADA INTO THE NORTHERN TIER OF THE EASTERN HALF OF THE CONUS. THIS MID/UPPER PATTERN IS SIMILAR TO WHAT OCCURRED MUCH OF WINTER 2013-14 AND WILL RESULT IN BELOW NORMAL TEMPERATURES CONTINUING INTO EARLY NEXT WORK WEEK. GUIDANCE IS CONSISTENT IN BRINGING A QUICK MOVING BUT DEEP SHORT WAVE TROUGH OR CLOSED LOW ACROSS THE REGION FRIDAY NIGHT...WITH A DECENT CHANCE FOR A PERIOD OF RAIN SHOWERS. MAINTAINED CHANCE POPS IN SMART BLEND...BUT THESE MAY NEED TO BE INCREASED IF TRENDS HOLD. AIR MASS WILL BE ANOMALOUSLY COOL...DIPPING CLOSE TO 0C AT 850 MB OVER FAR NORTHERN ILLINOIS BY 12Z SATURDAY. PROGRESSION OF SYSTEM WILL BE KEY IN HOW COLD LOWS ARE BY EARLY SATURDAY...AS LESS PROGRESSIVE/TIGHTER GRADIENT INDICATED BY RECENT ECMWF RUNS WOULD INTRODUCE CLOUD COVER CONCERNS. STILL...COLD ADVECTION ALONE LIKELY SUPPORTS LOWS IN 40S EVERYWHERE BUT IMMEDIATE CITY OF CHICAGO. POTENTIAL DOES EXIST FOR LAKE EFFECT RAIN SHOWERS INTO SATURDAY MORNING FOR PORTIONS OF SHORE...MAINLY NW IN...BEFORE SUBSIDENCE ARRIVES FROM EXPANSIVE HIGH PRESSURE SPREADING IN FROM WEST. HIGH TEMPERATURES LOOK TO STRUGGLE INTO LOWER 60S SATURDAY AFTERNOON. ANOMALOUSLY COOL AIR MASS AND GOOD RADIATIONAL COOLING SETUP WITH HIGH PRESSURE OVERHEAD SATURDAY NIGHT FAVORS AREAS OUTSIDE CHICAGO DOWN INTO AT LEAST LOWER 40S...WITH UPPER 30S POSSIBLE IN TYPICAL COLD SPOTS. DID UNDERCUT SMART BLEND INITIALIZATION FOR LOWS EARLY SUNDAY...AND LOWS IN 30S IN OUTLYING AREAS COULD BE MORE WIDESPREAD THAN IN CURRENT FORECAST IF THERE ARE NO CLOUD COVER ISSUES. WITH MEAN TROUGH OVER REGION...TEMPERATURES WILL REMAIN BELOW NORMAL REMAINDER OF EXTENDED...THOUGH SLOW MODERATION THROUGH 60S IS EXPECTED SUNDAY AND MONDAY. PREVIOUS TWO RUNS OF ECMWF INDICATE ANOTHER SHORT WAVE/REINFORCING COLD FRONT MONDAY/MONDAY NIGHT. CONFIDENCE IS LOWER IN THIS PERIOD DUE TO FEATURE BEING MUCH LESS ROBUST ON GFS AND ITS ENSEMBLES. FOR NOW...GRIDS INDICATE A SLIGHT CHANCE FOR SHOWERS ON MONDAY. RC && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 00Z... * ROUND ONE OF SHOWERS WITH EMBEDDED THUNDERSTORMS POSSIBLE ROUGHLY 04-08Z THIS EVENING. * ROUND TWO OF THUNDERSTORMS...WITH POTENTIALLY TORRENTIAL RAIN AT TIMES ROUGHLY 10Z-13Z. * LOW LEVEL WIND SHEAR CONDITIONS DEVELOPING OVERNIGHT. * ROUND THREE OF THUNDERSTORMS ROUGHLY 18Z-20Z DEVELOPING VERY NEAR OR OVER TERMINALS. * INCREASINGLY GUSTY SOUTH TO SOUTHWEST WINDS VEERING TO NORTHWEST MID AFTERNOON WEDNESDAY. BMD //DISCUSSION...UPDATED 00Z... AN ACTIVE PERIOD OF WEATHER IS EXPECTED OVER THE NEXT 24 HOURS OR SO WITH POSSIBLY UP TO THREE DISTINCT ROUNDS OF THUNDER POSSIBLE AT THE TERMINALS. MOST OF THE REMAINDER OF THE EVENING SHOULD BE QUIET AT THE TERMINALS WITH MODEST SOUTHERLY FLOW IN PLACE AND VFR CONDITIONS. HOWEVER A WARM FRONT IS IN PLACE TO OUR SOUTHWEST AND WILL LIFT ACROSS THE TERMINALS LATE THIS EVENING/TONIGHT BRINGING RAIN WITH EMBEDDED THUNDERSTORMS. IT APPEARS THE BEST TIME FRAME FOR THIS WOULD BE ROUGHLY 04-08Z AFTER WHICH THERE SHOULD BE A BIT OF A LULL IN THE COVERAGE/ACTIVITY AT THE TERMINALS. THE LOW LEVEL JET WILL BECOME STRONG TO OUR WEST OVERNIGHT AND A STRONGER COMPLEX OF THUNDERSTORMS IS EXPECTED TO DEVELOP. THESE STORMS ARE EXPECTED TO PUSH ACROSS THE CHICAGO TERMINALS ROUGHLY BETWEEN 10-13Z...A COUPLE HOURS EARLIER AT RFD. AS THE LOW LEVEL JET VEERS OVER THE AREA AROUND THIS TIME...LLWS CONDITIONS ARE PROGGED TO DEVELOP OVERHEAD. DEEPENING AREA OF LOW PRESSURE WILL LIFT ACROSS IOWA TONIGHT INTO EAST CENTRAL WISCONSIN BY MIDDAY WEDNESDAY. STRONG SOUTHERLY FLOW IS EXPECTED TO DEVELOP BECOMING INCREASINGLY GUSTY THROUGH THE PERIOD. WINDS GUSTING IN EXCESS OF 30 KT ARE EXPECTED AT TIMES THROUGH THE DAY WEDNESDAY...THOUGH THERE MAY BE CONSIDERABLE VARIABILITY IN THE MAGNITUDE DUE TO WARM ADVECTION RESULTING IN MARGINAL LOW LEVEL LAPSE RATES FOR MIXING. A COLD FRONT WILL SWEEP ACROSS THE AREA EARLY TO MID AFTERNOON AND WILL BE THE FOCUS OF RENEWED AFTERNOON THUNDERSTORM DEVELOPMENT. BASED ON THE TIMING OF THE FRONT...THUNDERSTORMS WILL LIKELY DEVELOP SOUTHEAST OF RFD...BUT MAY DEVELOP OVERHEAD OF NEAR THE CHICAGO TERMINALS BEFORE SHIFTING SOUTHEAST. THERE IS ALSO A CHANCE THAT THEY COULD DEVELOP SOUTH OF THE TERMINALS DEPENDING ON HOW THINGS EVOLVE TONIGHT. MAIN POINT BEING THERE REMAINS A LOT OF UNCERTAINTY IN THIS THIRD ROUND OF THUNDERSTORMS. BMD //ORD AND MDW CONFIDENCE...UPDATED 00Z... * LOW-MEDIUM CONFIDENCE IN WIDESPREAD THUNDERSTORMS THIS EVENING (ROUND ONE). * MEDIUM-HIGH CONFIDENCE IN HEAVY RAIN/THUNDERSTORMS (ROUND TWO) EARLY WEDNESDAY MORNING. * LOW CONFIDENCE IN THUNDERSTORMS ON STATION EARLY TO MID AFTERNOON WEDNESDAY. (ROUND THREE) * MEDIUM-HIGH CONFIDENCE IN WIND DIRECTION...LOW-MEDIUM CONFIDENCE IN WIND SPEEDS. MEDIUM CONFIDENCE IN LLWS. BMD //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THURSDAY...VFR. FRIDAY...CHC SHRA. SATURDAY...VFR. SUNDAY...VFR. MONDAY...SLT CHC SHRA. BMD && .MARINE... 221 PM CDT THE MAIN FORECAST CONCERNS CONTINUE TO CENTER AROUND A SIGNIFICANT STORM SYSTEM EXPECTED TO IMPACT THE GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT. SOUTHERLY WINDS ARE EXPECTED TO INCREASE RAPIDLY LATE TONIGHT AS A STRENGTHENING AREA OF LOW PRESSURE MOVES FROM IOWA INTO SOUTHWESTERN WISCONSIN. SOUTHERLY GALES OF 35 TO 40 KT ARE EXPECTED BY EARLY MORNING ACROSS APPROXIMATELY THE SOUTHERN HALF OF THE LAKE...AND THESE STRONG WINDS WILL CONTINUE THROUGH THE AFTERNOON. THE LOW IS THEN EXPECTED TO SHIFT ACROSS THE NORTHERN PORTION OF THE LAKE BY WEDNESDAY EVENING...AND THIS SHOULD RESULT IN A SHORT PERIOD OF LIGHT AND VARIABLE WINDS NEAR ITS TRACK EARLY THURSDAY EVENING. HOWEVER...ONCE THIS LOW SHIFTS EAST OF THE LAKE BY LATER WEDNESDAY EVENING...A STRONG COLD FRONT WILL PUSH OVER THE LAKE. THIS SHOULD ALLOW FOR A PERIOD OF STRONG NORTH-NORTHWESTERLY WINDS OVER THE LAKE INTO THURSDAY. AT THIS TIME...IT APPEARS THE MAIN THREAT FOR GALES MAY SHIFT OVER THE NORTHERN HALF OF THE LAKE INTO EARLY THURSDAY MORNING...WITH NEAR GALE FORCE WINDS POSSIBLE OVER THE SOUTHERN END OF THE LAKE. WINDS WILL GRADUALLY ABATE SOME INTO THE LATER PORTION OF THE WEEK AS HIGH PRESSURE BUILDS IN ACROSS THE PLAINS AND UPPER MIDWEST. HOWEVER...THE NORTHERLY FETCH WILL LIKELY CONTINUE TO PRODUCE SOME HIGHER 4 + FOOT WAVES THROUGH AT LEAST FRIDAY. ANOTHER SYSTEM COULD IMPACT PORTIONS OF THE LAKE ON SATURDAY...POSSIBLY LEADING TO A PERIOD OF ENHANCED NORTHERLY WINDS AGAIN. HOWEVER...UNCERTAINTY IS HIGH WITH THIS SYSTEM. IF THE SYSTEM DOES PAN OUT...IT COULD RESULT IN WAVES HIGH ENOUGH TO SUPPORT A SMALL CRAFT ADVISORY INTO SATURDAY. AS FOR HEADLINES...WE HAVE ISSUED A GALE WARNING FOR THE SOUTHERN HALF OF THE LAKE...INCLUDING THE NEAR SHORES...FOR THE DAY ON WED WHEN STRONG SOUTHERLY WINDS ARE EXPECTED. DUE TO UNCERTAINTIES ON HOW STRONG THE NORTHERLY WINDS WILL BE ON OVER SOUTHERN LAKE MICHIGAN ON THE BACK SIDE OF THE SYSTEM...WE HAVE OPTED TO KEEP THE WATCH IN PLACE FOR WEDNESDAY NIGHT FOLLOWING THE SOUTHERLY GALE EVENT. HOWEVER...OVER THE NORTHERN PORTION OF THE LAKE NORTHERLY GALES APPEAR MORE LIKELY WEDNESDAY NIGHT..SO WE HAVE ISSUED THE GALE WARNING THERE FOR WEDNESDAY EVENING THROUGH EARLY THURSDAY. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022- ILZ032...1 AM WEDNESDAY TO 1 PM WEDNESDAY. BEACH HAZARDS STATEMENT...ILZ006-ILZ014...5 AM WEDNESDAY TO NOON WEDNESDAY. FLASH FLOOD WATCH...ILZ023-ILZ033-ILZ039...7 AM WEDNESDAY TO 7 PM WEDNESDAY. IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...7 AM WEDNESDAY TO 7 PM WEDNESDAY. LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740- LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 AM WEDNESDAY TO 7 PM WEDNESDAY. GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 PM WEDNESDAY TO 10 AM THURSDAY. GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...5 PM WEDNESDAY TO 10 AM THURSDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
  [top] Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 901 PM CDT Tue Sep 9 2014 .UPDATE... ISSUED AT 900 PM CDT TUE SEP 9 2014 The 35-45kt low level jet around 850mb is progressing toward IL from the SW. Moisture transport is increasing as a result, with PWAT values climbing toward 2 inches. The nearly stationary warm from angled from NW to SE in eastern Missouri will continue to provide a lifting mechanism for shower/storm development the rest of the night. A progressive MCS is forecast by the high res models to move from NW Missouri across N IL overnight, which will possibly clip our NW counties after midnight. Areas NW of the IL river will have the best chances of getting heavy rain and strong winds from that complex. We kept categorical PoPs for that area overnight, with heavy rain in the grids. The flash flood watch coverage still looks good for timing and coverage. No changes will be needed there. The severe threat for Wed afternoon still hinges greatly on the amount of sunshine that develops ahead of the cold front. Wind shear will be present, as well as plenty of moisture, so instability will be the question-mark. Forecast soundings show limited instability even during the afternoon due to a moist adiabatic profile, but areas of clearing and heating can quickly produce high CAPEs. Will keep tomorrows forecast as is, with severe potential for nearly all of our counties except western portions of Knox and Stark counties. Even update mainly for weather/PoPs. && .SHORT TERM...(Tonight) ISSUED AT 305 PM CDT TUE SEP 9 2014 Issued a flash flood watch for areas from I-55 west from this afternoon through 7 pm Wed. Issued flash flood watch for east central IL for Wed afternoon and Wed evening. MCS still affecting a part of central IL with showers and thunderstorms sw of I-74 and west of I-57. Thunderstorms with heavy rains over parts of Morgan and southern Sangamon counties. Have increased chances of showers and thunderstorms over central and western areas tonight with heaviest rains shifting into areas nw of the IL river during the night. SPC continues a slight risk of severe storms from I-55 nw into tonight with main threat damaging wind gusts where 30% risk nw of IL river. Muggy lows in the upper 60s to around 70F with south southeast winds prevailing tonight. && .LONG TERM...(Wednesday through Tuesday) ISSUED AT 305 PM CDT TUE SEP 9 2014 Showers and thunderstorms will likely be ongoing to start the day for much of the forecast area west of I-55. This convective complex will be tied fairly closely to a deepening surface low that will be lifting into the Great Lakes region during the day. East of I-55 the day will likely start out dry. Then, attention turns to the cold front trailing from the surface low. This strong front will sweep through the forecast area, mainly during the Wednesday afternoon and evening hours. Unfortunately, there are still model disagreements with the speed of the front, differences that will likely have a significant impact on our severe weather threat. The ECMWF remains the slowest, while the NAM has trended faster and is now closer to the GFS speed. However, WPC does not favor the NAM`s recent trend of a deeper surface low and associated faster frontal speed. So, will continue to favor the more consistent ECMWF (although the GFS has been fairly consistent with is quicker solution). Severe storms and heavy rainfall are still a threat until the cold front clears the area. The main severe storm threat still appears to be in the Wednesday afternoon/evening hours along/ahead of the cold front where the best pre-frontal instability (1500-2500 j/kg) and bulk shear (35-45 kts) will be co-located. However, if a faster frontal speed verifies, the instability will likely end up quite a bit lower and reduce the severe threat. Any storms until the front clears the area have the potential to be heavy rain producers, with precipitable water values apt to be in excess 2 inches. Once the strong cold front clears the area by late Wednesday night, a much cooler than normal weather pattern should linger through the end of the forecast period. Upper level troffing should remain in place, accompanied by a Canadian surface high more often than not. There are still some stronger waves expected to track through the mean trof that may produce rainfall. However, model agreement in this regard still leaves much to be desired, especially next week. At this point, the best model clustering suggests showers are possible later Friday into Friday night, and this is the only period I have left slight chances for showers in place. Temperatures to start the period should average 60s for highs and 40s for lows, climbing into the 70s and 50s respectively by the end of the period. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) ISSUED AT 649 PM CDT TUE SEP 9 2014 Bands of thunderstorms will progress eastward toward I-57 this evening, but the eastern edge should not advance much farther than that until later tonight and tomorrow. We kept a VCSH for the eastern TAFs this evening. All TAFs included a short tempo for MVFR vis in any heavier downpours this evening. Ceilings could dip below 3k FT for short periods of time as well, but prevailing cloud levels should remain VFR. Low level wind shear still looks like a good bet for later tonight for our western TAFs as the southerly LLJ increases to 45kt around 2k FT. We did not include DEC and CMI in the LLWS for now, based on the latest RAP model output. As the cold front approaches tomorrow, winds will increase out of the south-southwest, with gusts to near 30kt at times. Strong to severe storms with damaging winds will be possible at all TAF sites tomorrow afternoon ahead of the front. We did not include any tempos for those conditions yet, but left VCTS in the afternoon for now. && .ILX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH through Wednesday evening FOR ILZ027>031- 036>038-040>042-047>051. FLASH FLOOD WATCH from Wednesday afternoon through late Wednesday night FOR ILZ043>046-052>057-061. && $$ UPDATE...SHIMON SHORT TERM...07 LONG TERM...BAK AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
258 PM CDT MON SEP 8 2014 .DISCUSSION... 247 PM CDT MAIN CONCERNS FOR THE FORECAST PERIOD WILL FOCUS ON THUNDERSTORMS AND HEAVY RAINFALL ASSOCIATED WITH AN UNUSUALLY STRONG LATE SUMMER COLD FRONT AND UPPER TROUGH IMPACTING THE REGION FROM TUESDAY NIGHT INTO WEDNESDAY NIGHT. FOLLOWING THE PASSAGE OF THIS SYSTEM...THE FOCUS WILL SHIFT TO THE TEMPERATURE FORECAST AND THE FIRST REAL TASTE OF AUTUMNAL WEATHER FOR LATER THIS WEEK. FOR THE REMAINDER OF THIS AFTERNOON INTO THE EVENING...CONTINUOUS WILL REMAIN QUIET. THE ONLY ITEM OF CONCERN IS AN OLD MCS TRACKING ACROSS NRN IOWA. DO NOT ANTICIPATE THAT ANY PCPN WILL HANG TOGETHER LONG ENOUGH TO IMPACT THE CWA...BUT RATHER EXPECT INCREASING MID AND HIGH CLOUDS ENCROACHING ON THE NRN PORTIONS OF THE CWA. THE FLOW PATTERN ALOFT CONTINUES TO BE VERY LOW AMPLITUDE WITH THE FASTER WESTERLIES ACROSS THE NRN CONUS AND BROAD RIDGING OVER THE SRN CONUS. WEAK SHORTWAVES RIPPLING THROUGH THE FAST ZONAL FLOW ALOFT WILL BRING THE INITIAL CHANCES FOR PCPN LATE TONIGHT. THE ANTICIPATED TRACK OF THE ASSOCIATED SHORT WAVE WOULD BRING THE GREATEST CHANCE FOR SHOWERS AND SOME SCATTERED THUNDERSTORMS...MOSTLY AFTER MIDNIGHT WITH SOME LINGERING PCPN POSSIBLE INTO EARLY TUESDAY MORNING. THE SYSTEM OF GREATER CONCERN IS SHAPING UP FOR LATE TUESDAY NIGHT THROUGH WEDNESDAY. THE LARGE SCALE MODELS HAVE BEEN CONSISTENT IN ADVERTISING A HEAVY RAIN EVENT WITH THE POSSIBILITY OF SEVERE THUNDERSTORMS. THROUGH TUESDAY...THE UPPER LEVEL PATTERN WILL UNDERGO AN AMPLIFICATION PROCESS WITH UPPER TROUGHING DEVELOPING OVER THE WRN CONUS WITH BROAD RIDGING OVER THE CNTRL AND ERN CONUS. THE UPPER TROUGH WILL TAP SOME RESIDUAL MOISTURE FROM THE REMNANTS OF EASTERN PACIFIC HURRICANE NORBERT. ADDITIONALLY...LEE TROUGH DEVELOPMENT OVER THE CENTRAL PLAINS WILL HELP OPEN UP THE GLFMEX AND INCREASINGLY SOUTHERLY TO SOUTHWESTERLY FLOW AT THE SFC ALOFT WILL SET UP AN EXTENDED PERIOD OF WARM/MOIST ADVECTION. THE LARGER SCALE MODEL GUIDANCE HAS BEEN CONSISTENT IN ADVERTISING COPIOUS AMOUNTS OF MOISTURE POOLING ALONG AND AHEAD OF THE SFC COLD FRONT...WITH AN AREA OF PWATS IN EXCESS OF 2 INCHES MOVING OVER THE REGION AS THE COLD FRONT PUSHES EWD ACROSS THE CNTRL PLAINS AND INTO THE MIDWEST. WITH THE STRONGEST WESTERLY SHUNTING TO THE NORTH WITH THE AMPLIFYING UPPER LEVEL PATTER...THE ASSOCIATED SFC LOW WILL TAKE A NELY TRACK FROM THE CNTRL PLAINS TUESDAY INTO CENTRAL WISCONSIN BY MIDDAY WEDNESDAY...AND THEN THROUGH THE UPPER GREAT LAKES WEDNESDAY NIGHT. THE NET EFFECT OF THIS EVOLUTION WILL BE TO SLOW THE PROGRESSION OF THE SRN END OF THE FRONT...WITH EXTENSIVE TRAINING OF THUNDERSTORMS IN THE DEEPER LEVEL SWLY FLOW ALOFT. WITH THE LATEST FORECAST UPDATE...WILL CARRY AROUND 2 INCHES OF STORM TOTAL WIDESPREAD QPF WITH THE SYSTEM FROM LATE TUESDAY NIGHT INTO EARLY WEDNESDAY EVENING. HOWEVER...WITH TRAINING THUNDERSTORMS LIKELY ALONG WITH A VERY MOIST AIRMASS...THE 2 INCH AMOUNTS MAY BE A CONSERVATIVE AREAL AVERAGE AMOUNT AS LOCALIZED TRAINING AND STRONG TO POTENTIALLY SEVERE THUNDERSTORMS WILL BE VERY EFFICIENT PCPN PRODUCERS. THE PERIOD OF TIME WHICH THE HEAVIEST RAINFALL IS EXPECTED WILL BE FROM LATE MORNING THROUGH LATE AFTERNOON WEDNESDAY AS THE LEADING EDGE OF A 50KT+ LOW LEVEL JET POINTS INTO NRN IL/SERN WI AND THEN SLOWLY TRANSLATES INTO NWRN INDIANA. THE STRONG VEERING OF WINDS THROUGH THE LOWER LEVELS SHOULD BE SUFFICIENT TO SUPPORT STRONG ROTATING UPDRAFTS CONDUCIVE TO SUPERCELL DEVELOPMENT ON THE LEADING EDGE OF THE LOW LEVEL JET...BUT ACTIVITY SHOULD EVOLVE INTO MORE ORGANIZED LINES OR CLUSTERS OF STORMS. THE GREATEST SEVERE THREAT SHOULD BE STRONG...DAMAGING WINDS GIVEN THE STRONG LOW LEVEL SHEAR. WHILE THE POSSIBILITY OF LARGE HAIL IS NOT OUT OF THE QUESTION...THE FREEZING LEVEL WILL BE CLOSE TO 16KFT...SO A CONSIDERABLE AMOUNT OF MELTING COULD OCCUR BEFORE HAIL REACHES THE GROUND. THE COLD FRONT SHOULD FINALLY PUSH EAST OF THE CWA...BRINGING AN END TO ANY LINGERING PCPN OVER THE FAR SERN PORTIONS OF THE CWA BY DAYBREAK EARLY THURSDAY MORNING. AS THE SFC LOW ASSOCIATED WITH THIS SYSTEM MOVES OFF INTO THE CANADIAN MARITIME PROVINCES THURSDAY NIGHT...A BROAD UPPER TROUGH WILL DROP OUT OF CANADA...BRINGING A SIGNIFICANTLY COLDER AIRMASS ACROSS THE NRN PLAINS AND UPPER MIDWEST. THE GFS/ECMWF ARE RELATIVELY CONSISTENT ON BRINGING THE 0C 850MB ISOTHERM CLOSE TO THE WISCONSIN BORDER BY THURSDAY EVENING WHILE BROAD HIGH PRESSURE SPREADS ACROSS THE CNTRL/NRN PLAINS AND UPPER MISSISSIPPI VALLEY. THROUGH THE DAY ON FRIDAY...THE 0C 850MB TEMPS ARE EXPECTED TO REACH INTO NRN IL...WHICH IS DOWNRIGHT CHILLY FOR MID SEPTEMBER. THE TEMPERATURE CONTRAST ACROSS THE COLD FRONT WILL BE VERY NOTABLE...WITH TEMPERATURES DROPPING OFF FROM THE UPPER 70S TO LOWER 80S ON WEDNESDAY INTO THE MIDDLE 40S TO AROUND 50F THURSDAY MORNING. STRONG...PERSISTENT COLD ADVECTION THROUGH A DEEP LAYER OF THE ATMOSPHERE WILL SET UP A MUCH COOLER PERIOD BEGINNING THURSDAY AND CONTINUING THROUGH THE WEEKEND WITH HIGHS GENERALLY IN THE UPPER 50S TO LOWER 60S. IF THIS PATTERN WOULD OCCUR JUST A COUPLE WEEKS LATER...WITH A LOWER SUN ANGLE...THE AREA COULD SEE HIGHS POTENTIALLY IN THE UPPER 40S TO LOWER 50S. HOWEVER...A HIGHER SUN ANGLE AND AMPLE SUNSHINE SHOULD LIMIT THE DEGREE OF COOLING. THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK...ONLY EXPECT SLOW MODERATION TO TEMPERATURES AS A STEADY STREAM OF NRN STREAM SHORTWAVE ENERGY WILL CONTINUE TO CARVE OUT A BROAD UPPER THROUGH OVER THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES REGIONS...GIVING LITTLE OPPORTUNITY FOR ANY SIGNIFICANT WARMING. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * SOUTHERLY WINDS SPORADICALLY GUSTING TO OVER 10 KT THIS AFTERNOON. * SLIGHT CHANCE FOR SHRA TUESDAY MORNING...WITH A CHANCE FOR TSRA IN THE WESTERN TRACON AREA. //DISCUSSION...UPDATED 18Z... HIGH PRESSURE IS BEGINNING TO PULL AWAY WITH SOUTHERLY WINDS ENCOMPASSING THE AREA. THE WIND DIRECTION AT CHICAGOLAND TAF SITES HAS AND LIKELY WILL CONTINUE TO BE SOMEWHAT VARIABLE BETWEEN SOUTHWEST AND SOUTHEAST. WHILE ORD AND MDW OBSERVATIONS HAVE INDICATED A FEW GUSTS IN EXCESS OF 10 KT...BELIEVE THAT SUCH GUSTS WILL BE INFREQUENT BASED ON THE ATMOSPHERIC PROFILE THIS AFTERNOON. PER OBSERVATIONAL TRENDS...THE LAKE BREEZE LOOKS TO VERY LIKELY STAY EAST OF ORD AND MDW. THE SYNOPTIC WIND WILL LIKELY STILL OFFER ENOUGH OF A SOUTHEAST COMPONENT TO TURN THE WINDS SLIGHTLY EAST OF SOUTH FROM TIME TO TIME THIS AFTERNOON...BUT AGAIN SPEEDS SHOULD BE 6-10 KT MUCH OF THE TIME. THUNDERSTORMS OVER WESTERN IA HAD DIFFICULTLY EVOLVING EASTWARD THIS MORNING. AS AN UPPER LEVEL DISTURBANCE MOVES INTO THIS AREA AND ADVANCED EAST...IT SHOULD HELP SHOWERS AND STORMS TO DO THE SAME. AN UPTICK IN COVERAGE IS EXPECTED THIS EVE ACROSS EASTERN IA AND POSSIBLY INTO NORTHWESTERN/WESTERN IL AS THE NIGHT PROGRESSES. THE ATMOSPHERE FAVORS ANY ORGANIZED AREA OF SHOWERS AND STORMS TO MOVE SOUTHEAST. RIGHT NOW ITS DIFFICULT TO SAY IF SHOWERS WILL REMAIN WEST OF CHICAGOLAND SITES TUESDAY MORNING...HOWEVER THERE IS GREATER CONFIDENCE THAT TSRA WILL STAY WEST/SOUTHWEST THROUGH TUESDAY MORNING. A POTENTIALLY ACTIVE AND IMPACTING PERIOD TO AVIATION WEATHER AT AREA TAF SITES APPEARS TO BE SHAPING UP LATE TUESDAY NIGHT THROUGH WEDNESDAY WITH A PROBABLE PERIOD OR PERIODS OF STORMS...GUSTY SOUTHERLY WINDS...AND POTENTIALLY LOW CLOUDS WEDNESDAY MORNING. //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM THAT WINDS WILL NOT FREQUENTLY BE GREATER THAN 10 KT. * MEDIUM IN SHRA REMAINING WEST OF THE AIRFIELDS TUESDAY MORNING. HIGH THAT TSRA WILL REMAIN WEST OF THE AIRFIELDS TUESDAY MORNING. //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 18Z... TUESDAY NIGHT...CHC SHRA/TSRA INCREASING OVERNIGHT. SOUTHERLY WINDS INCREASING WITH 40 KT FLOW AROUND 1000-1500 FT. WEDNESDAY...SHRA/TSRA LIKELY ESPECIALLY IN THE MORNING. GUSTY SOUTHERLY WINDS...AT TIMES TO 25 KT AND POSSIBLY 30 KT. MAINLY VFR...BUT PATCHY IFR IN STRONGER SHRA/TSRA. THURSDAY THROUGH SUNDAY...MAINLY VFR. MTF && .MARINE... 156 PM CDT THE MAIN FORECAST CONCERNS CENTER AROUND A SIGNIFICANT STORM SYSTEM EXPECTED TO IMPACT THE GREAT LAKES WEDNESDAY THROUGH THURSDAY. SOUTHERLY WINDS ARE EXPECTED TO INCREASE RAPIDLY AROUND OR SHORTLY AFTER DAYBREAK WEDNESDAY AS A STRENGTHENING AREA OF LOW PRESSURE MOVES FROM IOWA INTO SOUTHWESTERN WISCONSIN. SOUTHERLY GALES OF 35 TO 40 KT ARE PROBABLE BY MID TO LATE MORNING...ESPECIALLY ACROSS THE SOUTHERN HALF TO 2/3RDS OF THE LAKE...AND THESE STRONG WINDS LOOK TO CONTINUE THROUGH WEDNESDAY AFTERNOON. THE LOW IS THEN EXPECTED TO SHIFT SOMEWHERE ACROSS THE NORTHERN PORTION OF THE LAKE BY WEDNESDAY EVENING. THIS COULD RESULT IN A SHORT PERIOD OF LIGHT AND VARIABLE WINDS ACROSS NORTHERN SECTIONS OF THE LAKE EARLY WEDNESDAY EVENING. HOWEVER...ONCE THIS LOW SHIFTS EAST OF THE LAKE BY LATER WEDNESDAY EVENING...A STRONG COLD FRONT WILL PUSH OVER THE LAKE...WITH A PERIOD OF NORTHWESTERLY GALES LOOKING LIKE A DECENT BET ACROSS MOST OF THE LAKE INTO EARLY THURSDAY. THE WINDS WILL GRADUALLY ABATE SOME INTO THE LATER PORTION OF THE WEEK AS HIGH PRESSURE BUILDS IN ACROSS THE PLAINS AND UPPER MIDWEST. HOWEVER...THE NORTHERLY FETCH WILL LIKELY CONTINUE TO PRODUCE SOME HIGHER 4 + FOOT WAVES THROUGH FRIDAY. AS FOR HEADLINES...WE HAVE ISSUED A GALE WATCH FOR THE SOUTHERN 2/3RDS OF THE OPEN WATERS FROM 14 UTC WED THROUGH 15 UTC THURS AND FOR THE NORTHERN PORTION OF THE LAKE FROM 03 UTC THURS THROUGH 15 UTC THURS. HOWEVER...AT THIS TIME I HAVE OPTED TO LEAVE THE ILLINOIS AND INDIANA NEAR SHORES OUT OF THE GALE WATCH DUE TO THE OFFSHORE COMPONENT OF THE FLOW AND THEIR PROXIMITY TO THE SURFACE LOW. HOWEVER...GALE FORCE GUSTS ARE CERTAINLY POSSIBLE IN THE NEAR SHORES AS WELL...AND THIS MAY NEED TO BE ADDED TO THE WATCH IN FUTURE FORECAST UPDATES. AT THE VERY LEAST...A HIGH END SMALL CRAFT ADVISORY WITH WINDS TO 30 KT WILL LIKELY BE NEEDED FOR THE NEAR SHORE WATERS FOR WEDNESDAY THROUGH THE END OF THE WEEK. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WATCH...LMZ080-LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673- LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876- LMZ878...9 AM WEDNESDAY TO 10 AM THURSDAY. GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ563...7 PM WEDNESDAY TO 10 AM THURSDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 254 PM CDT Mon Sep 8 2014 .SHORT TERM...(Tonight) ISSUED AT 253 PM CDT MON SEP 8 2014 A surface high pressure ridge across extreme eastern and southeast IL early this afternoon will gradually shift to the east this evening. This will allow a light, south return flow to develop. The 18z surface analysis indicated dew points in the lower-middle 50s in much of central IL. However, moist low level air is as close as west central MO - so it doesn`t have far to go to make a return to central IL. A prominent outflow boundary from northeast to south central IA is expected to provide the focus for MCS development tonight. The short range models are is disagreement as to the track of the MCS and its associated remnants into west central IL overnight. Prefer the RAP, and to a certain extent a blend of the NAM and GFS, solution of the eastern edge of the precipitation shield getting close to the IL Valley after Midnight and just west of I-55 around daybreak. Drier air in eastern IL should work to erode the eastern edge from progressing much further. && .LONG TERM...(Tuesday through Monday) ISSUED AT 253 PM CDT MON SEP 8 2014 Not too many changes needed to the forecast over the next several days. While minor tweaks are required for the latest model trends, the overall picture has remained the same. Relatively low precipitation chances, mainly over the western portion of the forecast area, are appropriate through Tuesday night. These PoPs are the result of diurnal convection firing along an outflow boundary from tonight`s upstream MCS Tuesday and/or from the approach of our main midweek system by late Tuesday night. Our main precipitation threat is still on track for Wednesday and Wednesday night. This will occur courtesy of a potent upper level wave, associated surface low, and strong trailing cold front. A decent severe thunderstorm threat also exists ahead of the cold front, mainly Wednesday afternoon and evening. The main concern for nailing down too many specifics is the spread that persists with respect to the speed of trailing cold front. The slower solutions, most notably the 12Z ECMWF, will offer the most time for instability to build on Wednesday before the arrival of the front and increase the severe weather threat. Most models continue to point a general 35-45kt bulk shear gradient from south to north across the forecast area ahead of the front. A middle of the road solution to instability, accounting for differences in frontal speed, should support CAPE values of 1500-2500 j/kg. Heavy rain still looks to be a threat across the entire forecast area, severe weather or not, given the precipitable water values in excess of 2 inches forecast on the warm side of this system ahead of the cold front. Once the strong cold front clears the area by late Wednesday night, a much cooler than normal weather pattern should linger through the end of the forecast period. Upper level troffing should remain in place, accompanied by a Canadian surface high more often than not. There are still some stronger waves expected to track through the mean trof that may produce some rainfall over the last few days of the forecast. However, model agreement in this regard still leaves much to be desired. At this point, the best model clustering suggests showers are possible later Friday into Friday night, and this is the only period I have left slight chances for showers in place. Temperatures through the period should average 60s for highs and 40s for lows. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) ISSUED AT 100 PM CDT MON SEP 8 2014 VFR conditions can generally be expected the next 24 hours in central and eastern IL. A surface high pressure ridge will remain over eastern IL into this evening with a southerly return flow developing in central IL. However, the biggest question will be how much return flow of low level moisture occurs, especially west of I-55. Most of the shorter range models are depicting the development of another MCS in Iowa overnight. However, they differ on where the remnants may track. The HRRR seems to be too far north with its rainfall, while the NAM and RAP keep the bulk of the thunderstorms in SE Iowa and west central IL closer to the lower level theta-e ridge. With the best low level moisture advection/moisture transport expected to be near the MS River and the forecast of Corfidi vectors to be pointing toward the southeast, will only put a mention of VCTS in the forecast for KPIA, with the possibility of a VCSH along I-55 from KBMI-KSPI Tuesday morning after daybreak. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...MILLER LONG TERM...BAK AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
157 PM CDT MON SEP 8 2014 .DISCUSSION... 350 AM CDT PRIMARY FOCUS REMAINS ON DEEP LOW PRESSURE SYSTEM WHICH WILL MOVE THROUGH THE UPPER MIDWEST TUESDAY NIGHT THROUGH WEDNESDAY...AND ASSOCIATED RAIN/THUNDER TRENDS. MUCH COOLER AIR ARRIVES LATER WEDNESDAY NIGHT IN THE WAKE OF THIS SYSTEM...WITH A REINFORCING PUSH OF COOLER AIR FRIDAY. IN THE NEAR TERM...ARE REMAINS UNDER INFLUENCE OF SURFACE HIGH PRESSURE RIDGE TODAY. A SHORT WAVE MOVING NORTH OF THE CWA MAY SPREAD A LITTLE HIGH CLOUD COVER ALONG WITH SOME CIRRUS FROM CONVECTION WELL TO OUR NORTHWEST TODAY...THOUGH GENERALLY DRY AND MILD CONDITIONS EXPECTED. LOW LEVEL MOIST ADVECTION RAMPS UP TO OUR WEST TONIGHT WITH THUNDERSTORM DEVELOPMENT ANTICIPATED ACROSS THE UPPER MISSISSIPPI VALLEY. HIGH-RES GUIDANCE FOCUSES ON NORTHEAST IOWA LATER IN THE NIGHT...WITH INDICATIONS OF MCS REMNANTS MOVING INTO NORTHWEST LATE AND CONTINUING TO PROPAGATE SOUTHEAST ACROSS NORTH CENTRAL...WEST CENTRAL AND CENTRAL ILLINOIS AS SYSTEM DECAYS TUESDAY MORNING. DRIER LOW LEVEL AIR ASSOCIATED WITH THE RETREATING HIGH TO THE EAST...AND INSTABILITY AXIS FOCUSED FARTHER TO THE WEST/SOUTHWEST BOTH SUPPORT HIGHEST POPS ACROSS FAR SOUTHWESTERN PARTS OF THE CWA LATE TONIGHT AND EARLY TUESDAY. TURNING OUR ATTENTION BACK TO THE WEST TUESDAY...CYCLOGENESIS TAKES PLACE ACROSS THE PLAINS IN RESPONSE TO AMPLIFICATION OF UPPER TROUGH ACROSS THE WESTERN CONUS. RESULTING STRENGTHENING IN SOUTHERLY RETURN FLOW AND STRONG MOISTURE ADVECTION DEVELOPS INTO THE AREA TUESDAY NIGHT...WITH ANOMALOUSLY STRONG MOISTURE TRANSPORT FOR SEPTEMBER LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING. TAPPING OF SOUTHWEST MONSOONAL MOISTURE AS WELL AS SOME REMNANTS OF MOISTURE ASSOCIATED WITH HURRICANE NORBERT BRINGS PWATS OF 2+ INCHES INTO THE AREA IN PRE-COLD FRONTAL THETA-E PLUME. THIS SUPPORTS HEAVY RAINFALL THREAT (1.5-2.0 INCH AERIAL AMOUNTS) ACROSS NORTHERN IL EARLY WEDNESDAY...SHIFTING INTO CENTRAL IL AND NORTHWEST INDIANA WEDNESDAY AFTERNOON AHEAD OF COLD FRONT WHICH MOVES THROUGH DURING THE AFTERNOON AND EVENING HOURS. IN ADDITION...THIS STRONG DYNAMIC SYSTEM ALSO PRESENTS THE THREAT OF SEVERE WEATHER PARTICULARLY MIDDAY WEDNESDAY AND WEDNESDAY AFTERNOON AS STRONG DEEP LAYER SHEAR AND WEAK-MODERATE INSTABILITY COMBINE FOR SOME DEGREE OF A DAMAGING WIND THREAT. SPC HAS NORTHWEST PART OF THE CWA IN THE DAY 2 SLIGHT RISK...THOUGH AREA WILL BE IN LESS NOCTURNALLY FAVORED TIMING OF BEST STORM THREAT TUESDAY. DAY 3 SLIGHT RISK ACROSS MOST OF THE CWA WILL BE BETTER ALIGNED WITH DIURNAL CYCLE...ESPECIALLY ACROSS THE SOUTHEAST PORTION OF THE FORECAST AREA WHERE COLD FRONT WILL BE APPROACHING DURING THE AFTERNOON. EXTENSIVE CLOUD COVER AND PRECIP EARLY WEDNESDAY WILL NO DOUBT PLAY A LARGE ROLE IN MODULATING LOCATION AND EXTENT OF SEVERE THREAT...LEAVING SOME UNCERTAINTIES AT THIS DISTANCE. FIRST REAL TASTE OF AUTUMNAL COOL AIR SPREADS IN WEDNESDAY NIGHT AND THURSDAY AS THE LOW PULLS AWAY FROM THE GREAT LAKES. HIGHS IN THE 60S AND LOWS IN THE UPPER 40S/50S CHARACTERIZE THE REMAINDER OF THE FORECAST PERIOD...WITH HIGHS PERHAPS NOT GETTING ABOVE 65 FRIDAY-SATURDAY WITH A SECONDARY PUSH OF COOLER AIR. THIS SECONDARY COLD FRONT MAY ALSO SPUR A FEW SHOWERS FRIDAY WITH MID-LEVEL SHORT WAVE PASSING ACROSS THE AREA DURING THE DAY. SURFACE HIGH PRESSURE RIDGE OVER THE WEEKEND SHOULD ALLOW RELATIVELY DRY CONDITIONS DESPITE THE COOL TEMPS...THOUGH A FEW LAKE EFFECT SHOWERS WILL BE POSSIBLE ACROSS NORTHWEST INDIANA ESPECIALLY FRIDAY NIGHT AND SATURDAY WITH INSTABILITY INDUCED BY COOL AIR OVER MILD LAKE WATERS. RATZER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * SOUTHERLY WINDS SPORADICALLY GUSTING TO OVER 10 KT THIS AFTERNOON. * SLIGHT CHANCE FOR SHRA TUESDAY MORNING...WITH A CHANCE FOR TSRA IN THE WESTERN TRACON AREA. //DISCUSSION...UPDATED 18Z... HIGH PRESSURE IS BEGINNING TO PULL AWAY WITH SOUTHERLY WINDS ENCOMPASSING THE AREA. THE WIND DIRECTION AT CHICAGOLAND TAF SITES HAS AND LIKELY WILL CONTINUE TO BE SOMEWHAT VARIABLE BETWEEN SOUTHWEST AND SOUTHEAST. WHILE ORD AND MDW OBSERVATIONS HAVE INDICATED A FEW GUSTS IN EXCESS OF 10 KT...BELIEVE THAT SUCH GUSTS WILL BE INFREQUENT BASED ON THE ATMOSPHERIC PROFILE THIS AFTERNOON. PER OBSERVATIONAL TRENDS...THE LAKE BREEZE LOOKS TO VERY LIKELY STAY EAST OF ORD AND MDW. THE SYNOPTIC WIND WILL LIKELY STILL OFFER ENOUGH OF A SOUTHEAST COMPONENT TO TURN THE WINDS SLIGHTLY EAST OF SOUTH FROM TIME TO TIME THIS AFTERNOON...BUT AGAIN SPEEDS SHOULD BE 6-10 KT MUCH OF THE TIME. THUNDERSTORMS OVER WESTERN IA HAD DIFFICULTLY EVOLVING EASTWARD THIS MORNING. AS AN UPPER LEVEL DISTURBANCE MOVES INTO THIS AREA AND ADVANCED EAST...IT SHOULD HELP SHOWERS AND STORMS TO DO THE SAME. AN UPTICK IN COVERAGE IS EXPECTED THIS EVE ACROSS EASTERN IA AND POSSIBLY INTO NORTHWESTERN/WESTERN IL AS THE NIGHT PROGRESSES. THE ATMOSPHERE FAVORS ANY ORGANIZED AREA OF SHOWERS AND STORMS TO MOVE SOUTHEAST. RIGHT NOW ITS DIFFICULT TO SAY IF SHOWERS WILL REMAIN WEST OF CHICAGOLAND SITES TUESDAY MORNING...HOWEVER THERE IS GREATER CONFIDENCE THAT TSRA WILL STAY WEST/SOUTHWEST THROUGH TUESDAY MORNING. A POTENTIALLY ACTIVE AND IMPACTING PERIOD TO AVIATION WEATHER AT AREA TAF SITES APPEARS TO BE SHAPING UP LATE TUESDAY NIGHT THROUGH WEDNESDAY WITH A PROBABLE PERIOD OR PERIODS OF STORMS...GUSTY SOUTHERLY WINDS...AND POTENTIALLY LOW CLOUDS WEDNESDAY MORNING. //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM THAT WINDS WILL NOT BECOME SOUTHEAST AND FREQUENTLY GREATER THAN 10 KT. * MEDIUM IN SHRA REMAINING WEST OF THE AIRFIELDS TUESDAY MORNING. HIGH THAT TSRA WILL REMAIN WEST OF THE AIRFIELDS TUESDAY MORNING. //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 18Z... TUESDAY NIGHT...CHC SHRA/TSRA INCREASING OVERNIGHT. SOUTHERLY WINDS INCREASING WITH 40 KT FLOW AROUND 1000-1500 FT. WEDNESDAY...SHRA/TSRA LIKELY ESPECIALLY IN THE MORNING. GUSTY SOUTHERLY WINDS...AT TIMES TO 25 KT AND POSSIBLY 30 KT. MAINLY VFR...BUT PATCHY IFR IN STRONGER SHRA/TSRA. THURSDAY THROUGH SUNDAY...MAINLY VFR. MTF && .MARINE... 156 PM CDT THE MAIN FORECAST CONCERNS CENTER AROUND A SIGNIFICANT STORM SYSTEM EXPECTED TO IMPACT THE GREAT LAKES WEDNESDAY THROUGH THURSDAY. SOUTHERLY WINDS ARE EXPECTED TO INCREASE RAPIDLY AROUND OR SHORTLY AFTER DAYBREAK WEDNESDAY AS A STRENGTHENING AREA OF LOW PRESSURE MOVES FROM IOWA INTO SOUTHWESTERN WISCONSIN. SOUTHERLY GALES OF 35 TO 40 KT ARE PROBABLE BY MID TO LATE MORNING...ESPECIALLY ACROSS THE SOUTHERN HALF TO 2/3RDS OF THE LAKE...AND THESE STRONG WINDS LOOK TO CONTINUE THROUGH WEDNESDAY AFTERNOON. THE LOW IS THEN EXPECTED TO SHIFT SOMEWHERE ACROSS THE NORTHERN PORTION OF THE LAKE BY WEDNESDAY EVENING. THIS COULD RESULT IN A SHORT PERIOD OF LIGHT AND VARIABLE WINDS ACROSS NORTHERN SECTIONS OF THE LAKE EARLY WEDNESDAY EVENING. HOWEVER...ONCE THIS LOW SHIFTS EAST OF THE LAKE BY LATER WEDNESDAY EVENING...A STRONG COLD FRONT WILL PUSH OVER THE LAKE...WITH A PERIOD OF NORTHWESTERLY GALES LOOKING LIKE A DECENT BET ACROSS MOST OF THE LAKE INTO EARLY THURSDAY. THE WINDS WILL GRADUALLY ABATE SOME INTO THE LATER PORTION OF THE WEEK AS HIGH PRESSURE BUILDS IN ACROSS THE PLAINS AND UPPER MIDWEST. HOWEVER...THE NORTHERLY FETCH WILL LIKELY CONTINUE TO PRODUCE SOME HIGHER 4 + FOOT WAVES THROUGH FRIDAY. AS FOR HEADLINES...WE HAVE ISSUED A GALE WATCH FOR THE SOUTHERN 2/3RDS OF THE OPEN WATERS FROM 14 UTC WED THROUGH 15 UTC THURS AND FOR THE NORTHERN PORTION OF THE LAKE FROM 03 UTC THURS THROUGH 15 UTC THURS. HOWEVER...AT THIS TIME I HAVE OPTED TO LEAVE THE ILLINOIS AND INDIANA NEAR SHORES OUT OF THE GALE WATCH DUE TO THE OFFSHORE COMPONENT OF THE FLOW AND THEIR PROXIMITY TO THE SURFACE LOW. HOWEVER...GALE FORCE GUSTS ARE CERTAINLY POSSIBLE IN THE NEAR SHORES AS WELL...AND THIS MAY NEED TO BE ADDED TO THE WATCH IN FUTURE FORECAST UPDATES. AT THE VERY LEAST...A HIGH END SMALL CRAFT ADVISORY WITH WINDS TO 30 KT WILL LIKELY BE NEEDED FOR THE NEAR SHORE WATERS FOR WEDNESDAY THROUGH THE END OF THE WEEK. KJB && .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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 101 PM CDT Mon Sep 8 2014 .UPDATE... ISSUED AT 1027 AM CDT MON SEP 8 2014 Only minor updates made to tweak high temperatures up a degree or two for today. Surface ridging gradually shifting through eastern Illinois late this morning will result in a weak south return flow in west central and central IL today. This should allow highs to climb around 80 degrees this afternoon. Upstream surface observations and the 12z ILX sounding indicate there is still a lot of dry air in the lower atmosphere, so any cloud cover should mainly be restricted to high clouds from the MCS in Iowa. Late tonight, some of the short range models are indicating the development of another MCS in Iowa. The remnants of this may spill over into west central IL toward daybreak...and possibly just west of the I-55 corridor Tuesday morning before dissipating. Confidence in the eastward extent of this convection is not very high since there is quite a bit of short term model discrepancy and due to the presence of low level dry air that will need to be overcome. && .SHORT TERM...(Today) ISSUED AT 309 AM CDT MON SEP 8 2014 High pressure currently extending from New England to the Southern Plains will provide another pleasant day across central Illinois today. Despite cool early morning lows in the lower to middle 50s, dry airmass will heat quite efficiently thanks to abundant sunshine. With subsidence inversion lowering slightly from yesterday, mixing will only take place up to around 900mb today. This will result in similar high temperatures to yesterday, perhaps a degree or two warmer in the upper 70s to around 80 degrees. && .LONG TERM...(Tonight through Sunday) ISSUED AT 309 AM CDT MON SEP 8 2014 Short-wave trough evident on 07z/2am water vapor imagery over eastern South Dakota will track eastward tonight, triggering a cluster of showers and thunderstorms along the nose of a 30-35kt LLJ oriented into northern Iowa. This convection will track E/SE toward Illinois, but will encounter an unfavorably dry/stable airmass east of the Mississippi River. As a result, am expecting a distinct diminishing trend as storms push into west-central Illinois late tonight into Tuesday morning. Will continue with chance PoPs across the Illinois River Valley after midnight, with dry conditions expected through the entire night further east across east-central and southeast Illinois. Diurnal weakening trend will result in complete dissipation of thunderstorm cluster Tuesday morning, although widely scattered showers/thunder could re-develop along outflow boundary during the afternoon. As such, will carry low chance PoPs along/west of I-55, with dry weather further east. Will be a warm day as well, with high temperatures ranging from around 80 degrees northwest of the Illinois River where cloud debris will hold readings down a bit, to the middle 80s along/south of I-70. Main weather story is still on target for Tuesday night through Wednesday night, as a vigorous upper-level trough digs southeastward out of the Northern Rockies and an unseasonably strong surface low develops over western Kansas on Tuesday. Models are in good agreement that the low will deepen to around 992mb as it tracks to Lake Superior by Wednesday evening. Ahead of the low, an increasing W/SW LLJ will bring copious amounts of moisture into central Illinois Tuesday night into Wednesday, with all model solutions showing precipitable water values climbing to around 2.25. Trailing cold front is expected to push into the KILX CWA on Wednesday, accompanied by widespread showers and thunderstorms. Severe weather will be possible Wednesday afternoon and evening as the front progresses through the region. Main question will be degree of destabilization, as models are indicating dew points in the lower 70s and resulting CAPE values of 1500 to 2500J/kg. If this level of instability is realized, storms will quickly organize along/ahead of the front thanks to 0-6km bulk shear values increasing to between 30 and 40kt. Primary severe weather threats will be damaging wind gusts and high rainfall rates potentially leading to localized flash flooding. Have increased PoPs to categorical across the NW CWA late Tuesday night and across the board on Wednesday. Once front sinks into the Ohio River Valley, a cooler/drier airmass will arrive on Thursday. Due to strong CAA, high temperatures will drop into the upper 60s and lower 70s. Models have come into better agreement concerning the timing of the trailing 500mb trough axis, with all solutions taking it across central Illinois on Friday. Despite dry airmass, strong upper dynamics and steep lapse rates will be enough to trigger clouds and perhaps a few light showers on Friday. After that, cool and dry weather will be the rule over the weekend, with highs mainly in the 60s and overnight lows dropping into the 40s. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) ISSUED AT 100 PM CDT MON SEP 8 2014 VFR conditions can generally be expected the next 24 hours in central and eastern IL. A surface high pressure ridge will remain over eastern IL into this evening with a southerly return flow developing in central IL. However, the biggest question will be how much return flow of low level moisture occurs, especially west of I-55. Most of the shorter range models are depicting the development of another MCS in Iowa overnight. However, they differ on where the remnants may track. The HRRR seems to be too far north with its rainfall, while the NAM and RAP keep the bulk of the thunderstorms in SE Iowa and west central IL closer to the lower level theta-e ridge. With the best low level moisture advection/moisture transport expected to be near the MS River and the forecast of Corfidi vectors to be pointing toward the southeast, will only put a mention of VCTS in the forecast for KPIA, with the possibility of a VCSH along I-55 from KBMI-KSPI Tuesday morning after daybreak. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MILLER SHORT TERM...BARNES LONG TERM...BARNES AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
920 PM CDT TUE SEP 9 2014 .UPDATE... ISSUED AT 905 PM CDT TUE SEP 9 2014 REALLY THE ONLY CONCERN TONIGHT IS HEAVY RAIN AND FLOODING AS SEVERE THREAT VERY LOW WITH SATURATED SOUNDING AND LIMITED SUB CLOUD BUOYANCY. LINEAR MCS CONTINUES SAGGING S/SE INTO LOW LEVEL MOIST AXIS AND IS INTERCEPTING MAIN LOW LEVEL JET AND MOISTURE TRANSPORT FEED. MUCH OF CONVECTION AND HEAVY RAIN CONCERNS WILL EXIST NEAR TO SOUTH OF I-80 REST OF EVE... WITH STRATIFYING PCPN SHIELD ACROSS NORTH. CONCERNS EXIST THAT THE LONGER THIS CONVECTION CONTINUES TO OUR SOUTH TONIGHT INTERRUPTING FOCUS OF LOW LEVEL JET AND MOISTURE FEED...THE MORE UNCERTAINTY EXISTS WITH HEAVY RAIN THREAT DEVELOPING ACROSS NORTHERN CWA... ALTHOUGH CANNOT BE RULED OUT IF STORMS CAN WEAKEN TO OUR SOUTH ALLOWING LOW LEVEL JET TO REFOCUS FURTHER NORTH WITH NORTHWARD LIFTING WARM FRONT. HAVE TRENDED FORECASTS TOWARD HEAVIER RAINS TONIGHT ACROSS SOUTHERN HALF OF THE CWA... BUT WILL MAINTAIN FLASH FLOOD WATCH ALL AREAS DUE TO UNCERTAINTY. && .SYNOPSIS... ISSUED AT 330 PM CDT TUE SEP 9 2014 LOW PRESSURE OVER EXTREME SOUTHEAST CO HAD A WARM FRONT EXTENDED INTO NORTHERN MO INTO SOUTHERN IL. TEMPERATURES TO THE SOUTH OF THE FRONT WERE WELL IN THE 80S TO MID 90S WITH DEWPOINTS IN THE LOWER TO MID 70S. SBCAPES OF 4000 J/KG WERE OCCURRING IN WESTERN MO. TO THE NORTH OF THE FRONT IN THE RAIN COOLED AIR READINGS WERE ONLY IN THE UPPER 60S TO UPPER 70S. THE BEST PRESSURE FALLS WERE LOCATED IN WESTERN KS. PRECIPITABLE WATERS WERE AS HIGH AS 1.9 INCHES IN NORTHERN MO. DOPPLER RADAR CONTINUED TO SHOW FESTERING SHOWERS AND A FEW THUNDERSTORMS FROM EASTERN NEB INTO SOUTHEAST IA AND CENTRAL IL WITH WARM AIR ADVECTION INTO THE AREA. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 330 PM CDT TUE SEP 9 2014 HEADLINES...NOW THAT MUCH OF THE AREA HAS SATURATED SOILS THE FLASH FLOOD WATCH WILL CONTINUE TONIGHT INTO WEDNESDAY MORNING FOR THE ENTIRE CWA. TONIGHT...ADDITIONAL RAINFALL OF 1 TO 3 INCHES APPEAR LIKELY. SOME LOCATIONS MAY RECEIVE 4 TO 6 INCHES...ESPECIALLY IN ANY TRAINING/REPEATING STORMS. THIS AMOUNT OF RAIN ON VERY SATURATED SOILS WOULD CAUSE SERIOUS FLASH FLOODING. PRECIPITABLE WATERS WILL BE AT NEAR RECORD VALUES FOR SEPTEMBER...ABOUT 2.2 INCHES. THIS IS DUE TO RICH GULF MOISTURE COMBINED WITH MOISTURE FROM THE REMNANTS OF WHAT WAS MAJOR PACIFIC HURRICANE NORBERT. RAINFALL RATES WILL BE EXTREMELY HIGH SO VERY TORRENTIAL RAINS WILL ACCOMPANY THESE STORMS. CONFIDENCE IS VERY HIGH FOR THIS FLASH FLOOD EVENT BUT IS LOWER FOR THE SEVERE THREAT. THERE IS THE POTENTIAL FOR LOCALIZED WET MICROBURSTS DUE TO THE VERY SATURATED ATMOSPHERE BUT ANY HAIL SHOULD REMAIN BELOW SEVERE LEVELS. I AM CONCERNED FOR THE POTENTIAL FOR AN ISOLATED TORNADO OR TWO ON ANY BOUNDARY AS THE DEEP LAYER SHEAR BECOMES VERY STRONG EVEN WELL AFTER DARK AS THE SURFACE LOW DEEPENS AND TRACKS TOWARDS LA CROSSE WI BY 12Z WEDNESDAY. THE HRRR MESO MODEL SUGGESTS ACTIVITY INCREASING IN OUR SOUTHERN CWA LATE THIS AFTERNOON OR TOWARDS EVENING THEN SPREADING NORTHEAST AS THE EVENING PROGRESSES...WITH WIDESPREAD STORMS THEN OCCURRING OVERNIGHT. SOME OF THE STRONGER STORMS WILL ALSO PRODUCE FREQUENT TO CONTINUOUS DANGEROUS LIGHTNING. MINIMUM TEMPERATURES WILL BE IN THE MID 60S TO LOWER 70S. WEDNESDAY...DEEPENING CYCLONE WILL TRACK INTO THE GREAT LAKES REGION SENDING A STRONG COLD FRONT INTO OUR WESTERN CWA IN THE MORNING AND OUR EASTERN CWA IN THE EARLY AFTERNOON. THE THUNDERSTORMS WILL GRADUALLY DIMINISH AND SHIFT TO THE EAST OF THE CWA WITH THE FRONT. THE SEVERE THREAT APPEARS TO BE FARTHER TO THE EAST THAN EARLIER THOUGHT AND SPC HAS THE SLIGHT RISK ONLY IN OUR FAR SOUTHEAST COUNTIES...BUT THIS WILL DEPEND ON CLOUD COVER AND AMOUNT OF INSTABILITY. MAXIMUM TEMPERATURES SHOULD RANGE FROM THE UPPER 60S AT INDEPENDENCE IA TO THE UPPER 70S IN OUR FAR EAST/SOUTHEAST COUNTIES. .LONG TERM...(WEDNESDAY NIGHT THROUGH NEXT TUESDAY) ISSUED AT 330 PM CDT TUE SEP 9 2014 WEDNESDAY NIGHT THROUGH FRIDAY...SEASONABLY STRONG RIDGE STILL ON TRACK TO DUMP DOWN THE PLAINS AND UPPER MS RVR VALLEY THIS PERIOD. EXPECT MOST POST-FRONTAL RAINS TO BE OUT OF THE CWA AT START OF THE PERIOD...WITH JUST DEEPENING LLVL NORTHERLY FLOW COOL ADVECTING AND SCORING OUT THE CLOUD COVER EVENTUALLY BY THU MORNING. EVEN IF CLOUD COVER HOLDS ON TIL DAYLIGHT...LOWS TO BE ADVECTED DOWN INTO THE 40S IN MOST OF THE CWA. INCOMING CANADIAN AIR TO WARM ONLY INTO THE 60S THU EVEN WITH SOME SUNSHINE...WITH A QUICK DROP OFF AFTER SUNSET THU EVENING INTO THE 40S BEFORE INCREASING CLOUDS AHEAD OF THE NEXT SYSTEM TOWARD FRI MORNING HALTS TEMP DROP OFF. STILL SOME PHASING ISSUES TO BE HAMMERED OUT...BUT LATEST RUN MEDIUM RANGE SOLUTIONS SUGGEST SOME TYPE OF WAVE/POSSIBLY RATHER VIGOROUS...TO ROLL ACRS THE REGION ON FRI. THIS SYSTEM WILL NOT HAVE NEAR THE MOISTURE SOURCE OR THERMODYNAMICS TO WORK WITH AS THE CURRENT SYSTEM...BUT STILL SHOULD INDUCE A RAIN SHIELD THAT WILL OVERSPREAD MOST OF THE CWA FROM WEST TO EAST AS FRI PROGRESSES. CLOUD COVER AND PRECIP TO KEEP A LID ON TEMPS WITH MOST AREAS HELD IN THE 50S OR EVEN UPPER 40S AND NORTH WINDS MAKING FOR A RAW DAY. CURRENT INDICATIONS SUGGEST MOST AREAS TO GET FROM 0.10 UP CLOSE TO HALF AN INCH BY THE TIME THE RAIN PULLS OUT FRI EVENING. MODELS STILL VARYING ON PRECIP AND CLOUD COVER EXIT TIMING LATER FRI NIGHT...BUT WILL JUST KEEP PRECIP IN THE EVENING FOR NOW. POST-WAVE SUBSIDENCE MAY MAKE FOR A LATE NIGHT CLEAR OUT...BUT SOME CHANCE FOR SUBSIDENCE INVERSION TO TRAP CLOUDS INTO SAT MORNING LIMITING FRI NIGHT/SAT MORNING COLD POTENTIAL. THE GFS CONTINUES TO BE THE COLD MODEL WITH SOME UPPER 30S IN THE NORTHWESTERN THIRD OF THE DVN CWA AND LOWER 40S ELSEWHERE. THE ECMWF MORE IN THE WAY OF LOW TO MID 40S BUT KEEPS THE CLOUD COVER AND SOME MIXING SFC WINDS GOING INTO SAT MORNING. WITH EXTENT OF INCOMING UNSEASONABLY COLD AIRMASS...FEEL WITH ANY KIND OF CLEAR OUT/PARTIAL CLEARING AND SFC WIND DROP OFF UNDER 10 MPH LATE FRI NIGHT...THE COOLER GFS WILL PREVAIL. SATURDAY AND SUNDAY...HIGHS ONLY RECOVERING INTO THE UPPER 50S TO MID 60S SAT UNDER WEAK MIXING REGIME OF CANADIAN HIGH PRESSURE... THEN HOW COLD TO GO SAT NIGHT THE CHALLENGE. IF LLVL RETURN FLOW DOES NOT MATERIALIZE IN TIME AND THE SFC RIDGE PERSISTS LONGER BEFORE EASTWARD MIGRATION...SAT NIGHT MAY BE THE COOLER OF THE TWO COLD WINDOW NIGHTS BEING WATCHED RIGHT NOW...MORE IDEAL RADIATIONAL COOLING PARAMETERS IN LINE POSSIBLY. MORE WIDESPREAD MID TO UPPER 30S POSSIBLE ESPECIALLY EAST OF THE MS RVR CLOSER TO RIDGE CENTER. WAA ON BACK SIDE OF RIDGE COMPLEX MAY GENERATE SOME ELEVATED SHOWERS INTO THE WESTERN CWA BY LAT SUNDAY NIGHT...BUT CONFIDENCE LOW ON THAT SCENARIO. MONDAY THROUGH NEXT TUESDAY...NEXT WAVE WILL LOOK TO SHEAR ACRS THE UPPER MIDWEST SOMETIME THIS PERIOD FOR THE NEXT RAIN CHANCE...WITH THE 12Z RUN ECMWF MORE PHASED AN ORGANIZED WITH THIS SYSTEM MON NIGHT INTO TUE FOR MORE SIGNIFICANT PRECIP AS OPPOSED TO THE GFS. ..12.. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 550 PM CDT TUE SEP 9 2014 CONDITIONS TO DETERIORATE TO MVFR/OCNL IFR AS SHOWERS AND STORMS BECOME WIDESPREAD LATER THIS EVE THROUGH EARLY WED AM AHEAD OF A STRONG COLD FRONT. STORMS WILL BRING PERIODS OF VERY HEAVY RAIN... AND A FEW MAY PRODUCE GUSTY WINDS AND HAIL. PCPN WILL DIMINISH IN COVERAGE AND INTENSITY BY MID TO LATE WED AM... AS THE COLD FRONT BEGINS TO MOVE INTO THE AREA. THE FRONT WILL LIKELY COME THROUGH THE TERMINALS BETWEEN 16Z-20Z BRINGING A WIND SHIFT TO THE NORTHWEST AROUND 10-15 KTS WITH GUSTS POSSIBLE. SOME LOWER CIGS INTO IFR POSSIBLE ALONG AND BEHIND THE FRONT FOR A TIME. && .HYDROLOGY... THE RIVER WATCH WILL BE ON THROUGH MID WEEK. AFTER LAST NIGHT/S AND THIS MORNINGS RAINS...ANOTHER 1-4 INCHES TONIGHT INTO WED MORNING WILL DEFINITELY PRODUCE SOME FLOODING ON AREA TRIBUTARIES...DEPENDING ON HOW WIDESPREAD THE ADDITIONAL HEAVY RAIN WILL FALL IN THE LOCAL AREA OF CONCERN. RIVER BASINS TO WATCH FOR FLOODING POTENTIAL ON SOME OF THE FCST POINTS FROM WED THROUGH FRI MORNING ARE THE SKUNK... CEDAR...IOWA...WAPSI...ENGLISH...AND DES MOINES RIVERS. THE MAQUOKETA MAY GET CLOSE. IF NOT FLOODING THEN SIGNIFICANT WITHIN BANK RISES TO OCCUR. ..12.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...FLASH FLOOD WATCH UNTIL 7 AM CDT WEDNESDAY FOR BENTON-BUCHANAN- CEDAR-CLINTON-DELAWARE-DES MOINES-DUBUQUE-HENRY IA-IOWA- JACKSON-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA- MUSCATINE-SCOTT-VAN BUREN-WASHINGTON. IL...FLASH FLOOD WATCH UNTIL 9 AM CDT WEDNESDAY FOR BUREAU-CARROLL- HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-MERCER- PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE. MO...FLASH FLOOD WATCH UNTIL 7 AM CDT WEDNESDAY FOR CLARK-SCOTLAND. && $$ UPDATE...05 SYNOPSIS...HAASE SHORT TERM...HAASE LONG TERM...12 AVIATION...05 HYDROLOGY...12
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
703 PM CDT TUE SEP 9 2014 ...UPDATED FOR AVIATION DISCUSSION... .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 204 PM CDT TUE SEP 9 2014 LATEST RAP 400MB POTENTIAL VORTICITY APPEARS TO HAVE A DECENT HANDLE WITH AN UPPER LEVEL DISTURBANCE THAT WAS CROSSING THE COLORADO ROCKIES AT 18Z. GIVEN THE 18Z VERIFICATION WILL STAY CLOSE TO THE RAP ON TIMING OF THIS UPPER LEVEL FEATURE AS IT CROSSES EASTERN COLORADO AND WESTERN KANSAS LATER THIS EVENING. GIVEN LATE DAY INSTABILITY AND LOCATION OF LOW LEVEL FORCING AHEAD OF THIS UPPER LEVEL TROUGH NEAR A SURFACE BOUNDARY THAT WILL EXTEND FROM SOUTHEAST COLORADO INTO NORTH CENTRAL KANSAS THERE WILL BE A CHANCE FOR SCATTERED THUNDERSTORMS LATE THIS AFTERNOON ACROSS NORTH CENTRAL KANSAS AND PORTIONS OF WEST KANSAS. BASED ON THE 21Z TUESDAY AND 00Z WEDNESDAY CAPE AND 0-6KM SHEAR FROM THE NAM A FEW STORMS LATE TODAY MAY BE SEVERE WITH THE AREA MORE FAVORABLE FOR HAIL GOLF BALL SIZE OR LARGER ALONG WITH WIND GUST IN EXCESS OF 60 MPH WILL BE ALONG AND NORTH OF A DIGHTON AND LARNED LINE. THUNDERSTORMS WILL THEN INCREASE IN AREAL COVERAGE EARLY TONIGHT AS THE UPPER LEVEL DISTURBANCE CROSSES THE CENTRAL HIGH PLAINS AND A SURFACE BOUNDARY MOVES ACROSS SOUTHWEST KANSAS. THE AREA THAT WILL BE MORE FAVORABLE FOR WIDESPREAD THUNDERSTORMS EARLY TONIGHT WILL BE ALONG AND NORTH OF A 700MB +10C TO +13C BAROCLINIC ZONE. GIVEN THE 12Z NAM AND 12Z GFS THIS FAVORABLE AREA WILL BE NORTHEAST OF A SYRACUSE TO DODGE CITY THE PRATT LINE. ALSO GIVEN THE HIGH PRECIPITABLE WATER VALUES PERIODS THERE WILL BE A CHANCE FOR PERIODS OF HEAVY RAIN IN THIS AREA AS WELL. BUFR SOUNDINGS INDICATING WINDS NEAR THE SURFACE BEHIND THE COLD FRONT WILL RANGE FROM 20 TO 30 KNOTS AS THE LOWER LEVELS BEGIN TO SATURATE. BY 12Z WEDNESDAY THE DEPTH OF THIS LOW LEVEL MOISTURE APPROACHES 3000FT WHICH SUPPORTS INSERTING A SLIGHT CHANCE FOR LIGHT DRIZZLE FOR SEVERAL HOURS EARLY WEDNESDAY MORNING. BY LATE MORNING THIS LOW LEVEL MOISTURE WILL BEGIN TO ERODE FROM SOUTHWEST NORTHEAST AND GIVEN SOME AFTERNOON SUNSHINE ACROSS SOUTHWEST AND SOUTH CENTRAL KANSAS THE HIGHS ARE EXPECTED TO CLIMB BACK INTO THE MID 70S BASED ON THE 00Z THURSDAY 850MB TEMPERATURES. FURTHER NORTH, NEAR THE INTERSTATE 70 CORRIDOR THE CLOUDS AND 850MB TEMPERATURES AT 00Z THURSDAY SUGGEST HIGHS ON IN THE UPPER 60S TO NEAR 70. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 313 PM CDT TUE SEP 9 2014 THE TREND WILL BE FOR COOLER AND WETTER IN THE VERY EARLY PERIOD OF THE LONG TERM FORECAST. THE PERIOD FROM WEDNESDAY INTO THE BEGINNING OF THE WEEKEND WILL THEN BE FOLLOWED BY A MODERATE REBOUND BACK TOWARD THE 80S BY THE MIDDLE OF NEXT WEEK. ALL THREE MODELS, THE ECMWF, GFS AND NAM INDICATED PRECIPITATION ALONG A STRONG FRONTOGENETIC ZONE ACROSS CENTRAL AND FAR WESTERN KANSAS INTO SOUTHEAST COLORADO FROM LATE THURSDAY NIGHT AND SPREADING EAST OVER CENTRAL KANSAS FRIDAY MORNING. SOME VARIABILITY IS EXPECTED AS THE BETTER FORCING IN THE MID LEVELS IS NOT EXPECTED TO SLIDE ALL THE WAY THROUGH THE CWA INTO OKLAHOMA, HENCE A BAND OF HIGHER RAIN AMOUNTS COULD FALL SOMEWHERE FROM THE HIGHWAY 54 CORRIDOR NORTHWARD AS THE NAM SUGGESTS. OTHER LOCATIONS SHOULD STILL GET SOME, BUT GENERALLY MUCH LIGHTER PRECIPITATION AMOUNTS OF A FEW HUNDREDTHS AS THE SECONDARY FRONTAL BOUNDARY MOVES THROUGH THE REGION IN THE FORM OF SCATTERED SHOWERS IF NOT A PERIOD OF RAIN. OF MUCH LONGER DURATION AND IMPACT WILL BE THE WIDESPREAD STRATUS THROUGH THE AREA, INHIBITING INSOLATION AND ENHANCING COLD ADVECTION. THE NUMEROUS MODELS AND BLEND SOLUTIONS STRONGLY SUPPORTS LOW 50S ACROSS MUCH OF THE AREA FOR A HIGH TEMPERATURES ON FRIDAYS. TEMPERATURES THIS COOL WILL REPRESENT ONLY A FEW DEGREES ABOVE RECORD MIN-MAXIMUM TEMPERATURES FOR SEPTEMBER 12TH AT LEAST LOCALLY AT DDC. A WARMING TEND WILL BE SLOW THROUGH THE WEEKEND PERIOD. THE MEAN LAYER WILL RETURN TO GENERALLY ZONAL PATTERN BY SUNDAY AFTER THE LARGE WAVE EXISTS. THE NEXT WAVE WILL NOT BECOME A POTENTIAL IMPACT UNTIL AROUND LATE SUNDAY OR MONDAY. THE PATTERN SUGGEST SOUTHWEST KANSAS COULD BE SPLIT AS FAR AS UPPER DYNAMIC FORCING GOES, WITH POSSIBLE MCS ACTIVITY TO THE NORTH IN THE DAKOTAS AND NEBRASKA AND SHORTWAVE ENERGY IN THE PANHANDLES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 659 PM CDT TUE SEP 9 2014 ASIDE FROM SCATTERED THUNDERSTORMS WITH BRIEF STRONG WINDS THAT COULD AFFECT THE TERMINALS THROUGH THE EVENING, VFR CONDITIONS CAN BE EXPECTED, WITH SOUTH WINDS BECOMING NORTH BETWEEN 04 AND 08Z AFTER AS THE COLD FRONT PASSES. MVFR CIGS WILL LIKELY DEVELOP TOWARD MORNING WITH DIURNAL COOLING AND COLD ADVECTION. BUT WITH DAYTIME HEATING, SKIES SHOULD BECOME PARTLY SUNNY AFTER 16Z. && .PRELIMINARY POINT TEMPS/POPS... DDC 63 73 49 65 / 40 10 0 10 GCK 62 73 49 63 / 50 20 10 10 EHA 62 75 52 69 / 20 10 10 10 LBL 64 76 51 67 / 20 10 0 10 HYS 62 68 45 62 / 70 20 0 10 P28 70 78 53 71 / 30 10 0 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BURGERT LONG TERM...RUSSELL AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS JACKSON KY
259 PM EDT MON SEP 8 2014 .UPDATE... ISSUED AT 1208 PM EDT MON SEP 8 2014 FOG HAS FINALLY LIFTED. STRATUS DECK OVER PORTIONS OF THE AREA WILL CONTINUE TO RISE AND BREAK UP FOR GENERALLY PARTLY CLOUDY AFTERNOON SKIES. STILL CAN NOT RULE OUT SOME ISOLD TO SCT CONVECTION THIS AFTERNOON...THOUGH WITH TIME THOUGHTS ARE LEANING INCREASINGLY TOWARDS MORE ISOLD COVERAGE AND MAINLY IN OUR SOUTH AND FAR EAST. UPDATE ISSUED AT 1018 AM EDT MON SEP 8 2014 FOR THIS MORNINGS UPDATE BROUGHT GRIDS IN LINE WITH HOURLY OBS. STUBBORN FOG AND LOW STRATUS IS LINGERING ACROSS THE AREA THIS MORNING...MAINLY DUE TO NORTHEAST WINDS ACROSS MUCH OF THE CWA WHICH DO TEND TO KEEP LOW STRATUS IN PLACE. HOWEVER STILL EXPECT A GRADUAL LIFTING AND EROSION OF THE FOG AND STRATUS ONCE EFFECTS OF SUN ARE ABLE TO BURN THROUGH TO THE SFC. A WEAK SOUTHEASTERN DOWN SLOPE FLOW APPEARS TO BE KEEPING THE FOG AND STRATUS AT BAY ACROSS OUR HIGHER TERRAIN IN THE SOUTHEAST. MID LEVEL SHORT WAVE CONTINUES TO ROLL UP INTO THE MID OHIO VALLEY THIS MORNING. THIS FEATURE IS FAIRLY VISIBLE IN WATER VAPOR IMAGES. WHILE CAN NOT TOTALLY RULE OUT SOME SHOWER AND THUNDERSTORM ACTIVITY THROUGH THE DAY CONFIDENCE IS WANING CONSIDERABLY. THE RAP...AND TO A LESSER EXTENT GFS FCST SOUNDINGS ARE SHOWING A WEAK CAP ACROSS MUCH OF THE AREA. THIS IS SOMEWHAT IN LINE WITH ILN/OHX MORNING SOUNDINGS THOUGH BEING GENERALLY OUTSIDE OF THE INFLUENCE OF THE SHORTWAVE THEY MAY NOT BE A GOOD REPRESENTATION OF THE PROFILE ACROSS OUR AREA. DISCOUNTED THE NAM/S SOUNDING AS IN TYPICAL FASHION IT GREATLY OVERDOES BOUNDARY LAYER MOISTURE AND CONSEQUENTLY BOUNDARY LAYER INSTABILITY AND SOUNDING PARAMETERS. THE HRRR HAS TRENDED TOWARDS A BIT LESS COVERAGE IN ACTIVITY AS WELL...AND INITIATES A BIT LATER IN THE DAY THAN PREVIOUS RUNS. DID DELAY DEVELOPMENT OF ACTIVITY UNTIL LATE MORNING/EARLY AFTERNOON BUT IN GENERAL KEPT INHERITED ISOLD AND SCT POPS FOR THE AFTERNOON TIME FRAME. UPDATE ISSUED AT 730 AM EDT MON SEP 8 2014 TWEAKED THE GRIDS A BIT EARLY THIS MORNING TO FINE TUNE THE SKY COVER AND T/TD PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 345 AM EDT MON SEP 8 2014 07Z SFC ANALYSIS SHOWS COOL AND DRY HIGH PRESSURE SPRAWLED OUT FROM THE OHIO VALLEY THROUGH THE NEW ENGLAND STATES. GENERAL LOW PRESSURE IS FOUND OVER THE DEEP SOUTH AND ALONG THE SOUTHEAST COAST. NOT FAR FROM EAST KENTUCKY IS A STALLED FRONTAL BOUNDARY LURKING JUST TO THE SOUTH. THIS HAS HELPED TO PREVENT THE DRY COMPONENT OF THE HIGH PRESSURE FROM MAKING IT THROUGH ALL OF THE STATE AS DEW POINTS ALONG THE TENNESSEE BORDER ARE IN THE LOW AND MID 60S WHILE MID AND UPPER 50S EXIST TO THE NORTH. THESE NORTHERN SPOTS ARE ALSO ENJOYING TEMPERATURES DOWN INTO THE MIDDLE AND UPPER 50S...PARTICULARLY IN THE VALLEYS WHERE MOSTLY CLEAR SKIES HAVE ALLOWED FOR DECENT RADIATIONAL COOLING BELOW THE THERMAL INVERSION. MEANWHILE...RIDGES AND LOCATIONS TO THE SOUTH WITH HIGHER DEW POINTS ARE SEEING TEMPERATURES A FEW DEGREES MORE. A COUPLE LARGE PATCHES OF LOW CLOUDS ARE AFFECTING SOUTHEAST KENTUCKY EARLY THIS MORNING HELPING TO DISRUPT THE FOG FORMATION...THOUGH THERE WILL UNDOUBTEDLY BE PATCHY FOG...LOCALLY DENSE...IN MANY VALLEY LOCATIONS GENERALLY CORRESPONDING TO THE CLEAR SPOTS. THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH ANOTHER POCKET OF ENERGY ROLLING EAST THROUGH GENERALLY FLAT FLOW TODAY...HELPING TO LOWER HEIGHTS LOCALLY AND BRING SOME EXTRA LIFT TO THE AREA. THIS MOVES THROUGH BY EVENING WITH CONTINUED RELATIVELY FAST AND NEARLY ZONAL FLOW INTO THE DAY TUESDAY. LATE IN THE SHORT TERM PORTION OF THE FORECAST HEIGHTS WILL CLIMB A NOTCH AHEAD OF A LARGE AND DEEPENING TROUGH OVER THE ROCKY MOUNTAIN AND HIGH PLAINS STATES. WITH THE MODEL SIMILARITIES HAVE GONE MAINLY WITH A BLEND OF THE HRRR AND NAM12 FOR WX SPECIFICS DURING THE FIRST 12-18 HOURS AND THEN THE 00Z ECMWF/NAM12 THROUGH TUESDAY. SENSIBLE WEATHER WILL FEATURE A CONTINUED COOL AND DRY DAY ACROSS THE FAR NORTHWEST PARTS OF THE AREA WHILE TO THE SOUTHEAST THERE WILL BE MUCH MORE CLOUD COVER ALONG WITH A THREAT FOR SHOWERS THROUGH THE MORNING. BY MIDDAY THUNDER CHANCES WILL PICK UP OWING TO BUILDING INSTABILITY AND THE NEARBY FRONT BEING ACTED UPON BY THE PASSING MID LEVEL SHORT WAVE. THE PCPN THREAT AND SOME OF THE CLOUD COVER WILL RETREAT TO THE EAST LATER TONIGHT WITH ANOTHER NIGHT OF MINOR RIDGE TO VALLEY TEMPERATURE DIFFERENCES AMIDST A NW TO SE STRIATION IN DEW POINTS. DUE TO THIS ANTICIPATE PATCHY VALLEY FOG AFTER MIDNIGHT FOR MOST LOCATIONS...PARTICULARLY ONES THAT MANAGE TO SEE ANY RAIN DURING THE DAY AND EVENING. TUESDAY WILL BE QUIET AND DRY...BUT A TAD WARMER WHILE THE DEVELOPING LOW TO THE EAST STARTS TO LIFT NORTH ALONG THE SOUTH EAST ATLANTIC SEABOARD. STARTED WITH THE CONSSHORT FOR T...TD...AND WINDS...THROUGH THE FIRST 24 HOURS FOLLOWED BY THE SUPERBLEND UNTIL 00Z WED. PER USUAL...MADE MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS TONIGHT. AS FOR POPS...ENDED UP CLOSER TO THE LOWER MAV GUIDANCE TODAY AND SIMILAR TO A BLEND OF THE RATHER LOW NUMBERS THEREAFTER THROUGH THE REMAINDER OF THE SHORT TERM FORECAST. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 310 AM EDT MON SEP 8 2014 THE MODELS REMAIN IN GOOD AGREEMENT IN THE LONG TERM...WITH A LARGE RIDGE OF HIGH PRESSURE ALOFT INFLUENCING THE WEATHER OF EASTERN KENTUCKY TO BEGIN THE PERIOD. DRY WEATHER SHOULD BE ON TAP TUESDAY NIGHT INTO EARLY WEDNESDAY AFTERNOON AS HIGH PRESSURE REMAINS IN CONTROL. HOWEVER...THIS UPPER RIDGE WILL BE DISPLACED AS DEEP AREA OF LOW PRESSURE...BOTH ALOFT AND AT THE SURFACE...COMES TOGETHER OVER THE NORTHERN PLAINS AND BEGINS TO PUSH ACROSS THE NORTHERN MISSISSIPPI VALLEY ON WEDNESDAY. THE SURFACE COLD FRONT ASSOCIATED WITH THIS POTENT SYSTEM WILL BRING UNSETTLED WEATHER TO THE AREA WEDNESDAY NIGHT AND THURSDAY. THE PRIMARY CONCERN WITH THIS WEATHER SYSTEM WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. THE MODELS HAVE THE FRONT SLOWING DOWN AND NEARLY STALLING ACROSS OUR AREA ON THURSDAY. SHOWERS AND STORMS ARE EXPECTED TO FIRE ALL ALONG THE BOUNDARY AS LARGE AMOUNTS OF WARM MOIST AIR OFF THE GULF OF MEXICO IS CARRIED NORTHWARD INTO THE BOUNDARY ON SOUTHERLY WINDS. THE BEST CHANCE FOR RAIN LOOKS TO BE FROM LATE THURSDAY MORNING THROUGH LATE THURSDAY AFTERNOON WHEN MOISTURE FLOW INTO THE FRONTAL ZONE IS AT ITS PEAK. THERE WILL ALSO BE THE POTENTIAL FOR A FEW STRONG THUNDERSTORMS ON THURSDAY AS THE FRONT MOVES THROUGH AS THERE WILL BE STRONG DYNAMICS ASSOCIATED WITH THE BOUNDARY AND ITS PARENT UPPER LEVEL SYSTEM. THUNDERSTORMS SHOULD THEN GIVE WAY TO RAIN SHOWER BEHIND THE FRONT THURSDAY NIGHT AS THE COOLER AIR MOVES IN BEHIND THE FRONT. THE FRONT IS EXPECTED TO EVENTUALLY CLEAR THE AREA LATE THURSDAY NIGHT INTO EARLY FRIDAY MORNING...AS A LARGE RIDGE OF CANADIAN HIGH PRESSURE PUSHES IT OFF TO OUR EAST. THIS AREA OF HIGH PRESSURE WILL BRING A SIGNIFICANT PATTERN CHANGE TO THE MAJORITY OF THE CONUS EAST OF THE ROCKY MOUNTAINS FROM FRIDAY ONWARD. AFTER SLIGHTLY ABOVE NORMAL TEMPERATURES TUESDAY NIGHT AND WEDNESDAY...A PERIOD OF UNSEASONABLE COOLING WILL BE OCCURRING. HIGHS ON WEDNESDAY ARE EXPECTED TO TOP OUT IN THE MID TO UPPER 80S AS SOUTHERLY WINDS BRING WARM MOIST AIR FROM THE GULF OF MEXICO INTO THE REGION. ONCE THE FRONT ARRIVES ON THURSDAY...WIDESPREAD CLOUD COVER AND PRECIPITATION WILL KEEP TEMPERATURES WELL BELOW NORMAL...WITH HIGHS ONLY CLIMBING TO AROUND 80 BY THURSDAY AFTERNOON. ONCE THE BOUNDARY HAS CLEARED THE AREA LATE THURSDAY NIGHT...AN INVASION OF COOL AN DRY CANADIAN AIR WILL BEGIN TO OCCUR. WITH WINDS SHIFTING TO THE NORTH BEHIND THE FRONT...TEMPERATURES WILL BE HARD PRESSED TO CLIMB INTO THE MID 70S ON FRIDAY. THE COOL WEATHER WILL THEN PERSIST THROUGH THE WEEKEND AS THE RIDGE OF HIGH PRESSURE BECOMES MORE FIRMLY ESTABLISHED. HIGH TEMPERATURES ON SATURDAY ARE EXPECTED TO ONLY CLIMB TO AROUND 70 WITH HIGHS ON SUNDAY ONLY WARMING INTO THE LOW 70S. OVERNIGHT LOWS IN THE 50S ARE EXPECTED AREA WIDE FRIDAY AND SATURDAY NIGHT AS THE COOL CANADIAN AIR POURS INTO THE REGION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 259 PM EDT MON SEP 8 2014 PESKY LOW STRATUS AND FOG FINALLY LIFTED BY MID DAY. STILL SEEING SOME INTERMITTENT MVFR CIGS AT A FEW PLACES BUT DAYTIME HEATING SHOULD CONTINUE TO WORK ITS MAGIC LIFTING BASES JUST A BIT MORE THROUGH THE AFTERNOON. RADAR DOES SHOW SOME SHOWER ACTIVITY KICKING OFF. BUT DEVELOPMENT HAS BEEN SLOW. HIGH RES MODELS SUGGEST THAT A CLUSTER OF STORMS MAY DEVELOP AND MOVE NORTHWARD OUT OF TN LATE THIS AFTERNOON...AFFECTING MAINLY OUR SOUTHWESTERN TERMINALS. WILL WATCH CLOSELY BUT CURRENT THINKING IS THAT ACTIVITY WILL GENERALLY LEAN TOWARDS BEING MORE ISOLD OVER THOSE AREAS AND MORE SCATTERED IN NATURE OVER OUR FAR SOUTH AND EAST. EXPECT FOG TO REDEVELOP ACROSS THE AREA AGAIN TONIGHT...BUT NOT QUITE AS WIDESPREAD AND DENSE AS THIS MORNING. WINDS WILL BE LIGHT THROUGH THE FORECAST PERIOD... GENERALLY FROM THE WEST SOUTHWEST DURING DAYLIGHT HOURS. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...RAY SHORT TERM...GREIF LONG TERM...AR AVIATION...RAY
AREA FORECAST DISCUSSION
NWS JACKSON KY
1208 PM EDT MON SEP 8 2014 .UPDATE... ISSUED AT 1208 PM EDT MON SEP 8 2014 FOG HAS FINALLY LIFTED. STRATUS DECK OVER PORTIONS OF THE AREA WILL CONTINUE TO RISE AND BREAK UP FOR GENERALLY PARTLY CLOUDY AFTERNOON SKIES. STILL CAN NOT RULE OUT SOME ISOLD TO SCT CONVECTION THIS AFTERNOON...THOUGH WITH TIME THOUGHTS ARE LEANING INCREASINGLY TOWARDS MORE ISOLD COVERAGE AND MAINLY IN OUR SOUTH AND FAR EAST. UPDATE ISSUED AT 1018 AM EDT MON SEP 8 2014 FOR THIS MORNINGS UPDATE BROUGHT GRIDS IN LINE WITH HOURLY OBS. STUBBORN FOG AND LOW STRATUS IS LINGERING ACROSS THE AREA THIS MORNING...MAINLY DUE TO NORTHEAST WINDS ACROSS MUCH OF THE CWA WHICH DO TEND TO KEEP LOW STRATUS IN PLACE. HOWEVER STILL EXPECT A GRADUAL LIFTING AND EROSION OF THE FOG AND STRATUS ONCE EFFECTS OF SUN ARE ABLE TO BURN THROUGH TO THE SFC. A WEAK SOUTHEASTERN DOWN SLOPE FLOW APPEARS TO BE KEEPING THE FOG AND STRATUS AT BAY ACROSS OUR HIGHER TERRAIN IN THE SOUTHEAST. MID LEVEL SHORT WAVE CONTINUES TO ROLL UP INTO THE MID OHIO VALLEY THIS MORNING. THIS FEATURE IS FAIRLY VISIBLE IN WATER VAPOR IMAGES. WHILE CAN NOT TOTALLY RULE OUT SOME SHOWER AND THUNDERSTORM ACTIVITY THROUGH THE DAY CONFIDENCE IS WANING CONSIDERABLY. THE RAP...AND TO A LESSER EXTENT GFS FCST SOUNDINGS ARE SHOWING A WEAK CAP ACROSS MUCH OF THE AREA. THIS IS SOMEWHAT IN LINE WITH ILN/OHX MORNING SOUNDINGS THOUGH BEING GENERALLY OUTSIDE OF THE INFLUENCE OF THE SHORTWAVE THEY MAY NOT BE A GOOD REPRESENTATION OF THE PROFILE ACROSS OUR AREA. DISCOUNTED THE NAM/S SOUNDING AS IN TYPICAL FASHION IT GREATLY OVERDOES BOUNDARY LAYER MOISTURE AND CONSEQUENTLY BOUNDARY LAYER INSTABILITY AND SOUNDING PARAMETERS. THE HRRR HAS TRENDED TOWARDS A BIT LESS COVERAGE IN ACTIVITY AS WELL...AND INITIATES A BIT LATER IN THE DAY THAN PREVIOUS RUNS. DID DELAY DEVELOPMENT OF ACTIVITY UNTIL LATE MORNING/EARLY AFTERNOON BUT IN GENERAL KEPT INHERITED ISOLD AND SCT POPS FOR THE AFTERNOON TIME FRAME. UPDATE ISSUED AT 730 AM EDT MON SEP 8 2014 TWEAKED THE GRIDS A BIT EARLY THIS MORNING TO FINE TUNE THE SKY COVER AND T/TD PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 345 AM EDT MON SEP 8 2014 07Z SFC ANALYSIS SHOWS COOL AND DRY HIGH PRESSURE SPRAWLED OUT FROM THE OHIO VALLEY THROUGH THE NEW ENGLAND STATES. GENERAL LOW PRESSURE IS FOUND OVER THE DEEP SOUTH AND ALONG THE SOUTHEAST COAST. NOT FAR FROM EAST KENTUCKY IS A STALLED FRONTAL BOUNDARY LURKING JUST TO THE SOUTH. THIS HAS HELPED TO PREVENT THE DRY COMPONENT OF THE HIGH PRESSURE FROM MAKING IT THROUGH ALL OF THE STATE AS DEWPOINTS ALONG THE TENNESSEE BORDER ARE IN THE LOW AND MID 60S WHILE MID AND UPPER 50S EXIST TO THE NORTH. THESE NORTHERN SPOTS ARE ALSO ENJOYING TEMPERATURES DOWN INTO THE MIDDLE AND UPPER 50S...PARTICULARLY IN THE VALLEYS WHERE MOSTLY CLEAR SKIES HAVE ALLOWED FOR DECENT RADIATIONAL COOLING BELOW THE THERMAL INVERSION. MEANWHILE...RIDGES AND LOCATIONS TO THE SOUTH WITH HIGHER DEWPOINTS ARE SEEING TEMPERATURES A FEW DEGREES MORE. A COUPLE LARGE PATCHES OF LOW CLOUDS ARE AFFECTING SOUTHEAST KENTUCKY EARLY THIS MORNING HELPING TO DISRUPT THE FOG FORMATION...THOUGH THERE WILL UNDOUBTEDLY BE PATCHY FOG...LOCALLY DENSE...IN MANY VALLEY LOCATIONS GENERALLY CORRESPONDING TO THE CLEAR SPOTS. THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH ANOTHER POCKET OF ENERGY ROLLING EAST THROUGH GENERALLY FLAT FLOW TODAY...HELPING TO LOWER HEIGHTS LOCALLY AND BRING SOME EXTRA LIFT TO THE AREA. THIS MOVES THROUGH BY EVENING WITH CONTINUED RELATIVELY FAST AND NEARLY ZONAL FLOW INTO THE DAY TUESDAY. LATE IN THE SHORT TERM PORTION OF THE FORECAST HEIGHTS WILL CLIMB A NOTCH AHEAD OF A LARGE AND DEEPENING TROUGH OVER THE ROCKY MOUNTAIN AND HIGH PLAINS STATES. WITH THE MODEL SIMILARITIES HAVE GONE MAINLY WITH A BLEND OF THE HRRR AND NAM12 FOR WX SPECIFICS DURING THE FIRST 12-18 HOURS AND THEN THE 00Z ECMWF/NAM12 THROUGH TUESDAY. SENSIBLE WEATHER WILL FEATURE A CONTINUED COOL AND DRY DAY ACROSS THE FAR NORTHWEST PARTS OF THE AREA WHILE TO THE SOUTHEAST THERE WILL BE MUCH MORE CLOUD COVER ALONG WITH A THREAT FOR SHOWERS THROUGH THE MORNING. BY MIDDAY THUNDER CHANCES WILL PICK UP OWING TO BUILDING INSTABILITY AND THE NEARBY FRONT BEING ACTED UPON BY THE PASSING MID LEVEL SHORT WAVE. THE PCPN THREAT AND SOME OF THE CLOUD COVER WILL RETREAT TO THE EAST LATER TONIGHT WITH ANOTHER NIGHT OF MINOR RIDGE TO VALLEY TEMPERATURE DIFFERENCES AMIDST A NW TO SE STRIATION IN DEWPOINTS. DUE TO THIS ANTICIPATE PATCHY VALLEY FOG AFTER MIDNIGHT FOR MOST LOCATIONS...PARTICULARLY ONES THAT MANAGE TO SEE ANY RAIN DURING THE DAY AND EVENING. TUESDAY WILL BE QUIET AND DRY...BUT A TAD WARMER WHILE THE DEVELOPING LOW TO THE EAST STARTS TO LIFT NORTH ALONG THE SOUTH EAST ATLANTIC SEABOARD. STARTED WITH THE CONSSHORT FOR T...TD...AND WINDS...THROUGH THE FIRST 24 HOURS FOLLOWED BY THE SUPERBLEND UNTIL 00Z WED. PER USUAL...MADE MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS TONIGHT. AS FOR POPS...ENDED UP CLOSER TO THE LOWER MAV GUIDANCE TODAY AND SIMILAR TO A BLEND OF THE RATHER LOW NUMBERS THEREAFTER THROUGH THE REMAINDER OF THE SHORT TERM FORECAST. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 310 AM EDT MON SEP 8 2014 THE MODELS REMAIN IN GOOD AGREEMENT IN THE LONG TERM...WITH A LARGE RIDGE OF HIGH PRESSURE ALOFT INFLUENCING THE WEATHER OF EASTERN KENTUCKY TO BEGIN THE PERIOD. DRY WEATHER SHOULD BE ON TAP TUESDAY NIGHT INTO EARLY WEDNESDAY AFTERNOON AS HIGH PRESSURE REMAINS IN CONTROL. HOWEVER...THIS UPPER RIDGE WILL BE DISPLACED AS DEEP AREA OF LOW PRESSURE...BOTH ALOFT AND AT THE SURFACE...COMES TOGETHER OVER THE NORTHERN PLAINS AND BEGINS TO PUSH ACROSS THE NORTHERN MISSISSIPPI VALLEY ON WEDNESDAY. THE SURFACE COLD FRONT ASSOCIATED WITH THIS POTENT SYSTEM WILL BRING UNSETTLED WEATHER TO THE AREA WEDNESDAY NIGHT AND THURSDAY. THE PRIMARY CONCERN WITH THIS WEATHER SYSTEM WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. THE MODELS HAVE THE FRONT SLOWING DOWN AND NEARLY STALLING ACROSS OUR AREA ON THURSDAY. SHOWERS AND STORMS ARE EXPECTED TO FIRE ALL ALONG THE BOUNDARY AS LARGE AMOUNTS OF WARM MOIST AIR OFF THE GULF OF MEXICO IS CARRIED NORTHWARD INTO THE BOUNDARY ON SOUTHERLY WINDS. THE BEST CHANCE FOR RAIN LOOKS TO BE FROM LATE THURSDAY MORNING THROUGH LATE THURSDAY AFTERNOON WHEN MOISTURE FLOW INTO THE FRONTAL ZONE IS AT ITS PEAK. THERE WILL ALSO BE THE POTENTIAL FOR A FEW STRONG THUNDERSTORMS ON THURSDAY AS THE FRONT MOVES THROUGH AS THERE WILL BE STRONG DYNAMICS ASSOCIATED WITH THE BOUNDARY AND ITS PARENT UPPER LEVEL SYSTEM. THUNDERSTORMS SHOULD THEN GIVE WAY TO RAIN SHOWER BEHIND THE FRONT THURSDAY NIGHT AS THE COOLER AIR MOVES IN BEHIND THE FRONT. THE FRONT IS EXPECTED TO EVENTUALLY CLEAR THE AREA LATE THURSDAY NIGHT INTO EARLY FRIDAY MORNING...AS A LARGE RIDGE OF CANADIAN HIGH PRESSURE PUSHES IT OFF TO OUR EAST. THIS AREA OF HIGH PRESSURE WILL BRING A SIGNIFICANT PATTERN CHANGE TO THE MAJORITY OF THE CONUS EAST OF THE ROCKY MOUNTAINS FROM FRIDAY ONWARD. AFTER SLIGHTLY ABOVE NORMAL TEMPERATURES TUESDAY NIGHT AND WEDNESDAY...A PERIOD OF UNSEASONABLE COOLING WILL BE OCCURRING. HIGHS ON WEDNESDAY ARE EXPECTED TO TOP OUT IN THE MID TO UPPER 80S AS SOUTHERLY WINDS BRING WARM MOIST AIR FROM THE GULF OF MEXICO INTO THE REGION. ONCE THE FRONT ARRIVES ON THURSDAY...WIDESPREAD CLOUD COVER AND PRECIPITATION WILL KEEP TEMPERATURES WELL BELOW NORMAL...WITH HIGHS ONLY CLIMBING TO AROUND 80 BY THURSDAY AFTERNOON. ONCE THE BOUNDARY HAS CLEARED THE AREA LATE THURSDAY NIGHT...AN INVASION OF COOL AN DRY CANADIAN AIR WILL BEGIN TO OCCUR. WITH WINDS SHIFTING TO THE NORTH BEHIND THE FRONT...TEMPERATURES WILL BE HARD PRESSED TO CLIMB INTO THE MID 70S ON FRIDAY. THE COOL WEATHER WILL THEN PERSIST THROUGH THE WEEKEND AS THE RIDGE OF HIGH PRESSURE BECOMES MORE FIRMLY ESTABLISHED. HIGH TEMPERATURES ON SATURDAY ARE EXPECTED TO ONLY CLIMB TO AROUND 70 WITH HIGHS ON SUNDAY ONLY WARMING INTO THE LOW 70S. OVERNIGHT LOWS IN THE 50S ARE EXPECTED AREA WIDE FRIDAY AND SATURDAY NIGHT AS THE COOL CANADIAN AIR POURS INTO THE REGION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 750 AM EDT MON SEP 8 2014 A LOW CLOUD DECK REMAINS IN PLACE OVER MUCH OF EAST KENTUCKY WITH STILL SOME WESTWARD EXPANSION NOTED IN THE SATELLITE TRENDS. THESE CLOUDS ARE GENERALLY IN THE MVFR RANGE FOR CIGS...BUT THERE ARE AREAS OF MUCH LOWER CIGS DOWN TO LIFR IN THE SOUTH ALONG WITH LOW VIS FROM FOG. ISOLATED TO SCATTERED RAIN SHOWERS ARE EXPECTED TO REDEVELOP... MAINLY EAST OF JKL...BY MID MORNING AND PERSISTING INTO THE AFTERNOON. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT AS WELL THROUGH THE EARLY EVENING HOURS. HAVE A VCTS FOR THIS IN THE ALL THE TAFS EXCEPT SYM. WINDS THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE ACROSS THE FORECAST AREA. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...RAY SHORT TERM...GREIF LONG TERM...AR AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS JACKSON KY
1018 AM EDT MON SEP 8 2014 .UPDATE... ISSUED AT 1018 AM EDT MON SEP 8 2014 FOR THIS MORNINGS UPDATE BROUGHT GRIDS IN LINE WITH HOURLY OBS. STUBBORN FOG AND LOW STRATUS IS LINGERING ACROSS THE AREA THIS MORNING...MAINLY DUE TO NORTHEAST WINDS ACROSS MUCH OF THE CWA WHICH DO TEND TO KEEP LOW STRATUS IN PLACE. HOWEVER STILL EXPECT A GRADUAL LIFTING AND EROSION OF THE FOG AND STRATUS ONCE EFFECTS OF SUN ARE ABLE TO BURN THROUGH TO THE SFC. A WEAK SOUTHEASTERN DOWN SLOPE FLOW APPEARS TO BE KEEPING THE FOG AND STRATUS AT BAY ACROSS OUR HIGHER TERRAIN IN THE SOUTHEAST. MID LEVEL SHORT WAVE CONTINUES TO ROLL UP INTO THE MID OHIO VALLEY THIS MORNING. THIS FEATURE IS FAIRLY VISIBLE IN WATER VAPOR IMAGES. WHILE CAN NOT TOTALLY RULE OUT SOME SHOWER AND THUNDERSTORM ACTIVITY THROUGH THE DAY CONFIDENCE IS WANING CONSIDERABLY. THE RAP...AND TO A LESSER EXTENT GFS FCST SOUNDINGS ARE SHOWING A WEAK CAP ACROSS MUCH OF THE AREA. THIS IS SOMEWHAT IN LINE WITH ILN/OHX MORNING SOUNDINGS THOUGH BEING GENERALLY OUTSIDE OF THE INFLUENCE OF THE SHORTWAVE THEY MAY NOT BE A GOOD REPRESENTATION OF THE PROFILE ACROSS OUR AREA. DISCOUNTED THE NAM/S SOUNDING AS IN TYPICAL FASHION IT GREATLY OVERDOES BOUNDARY LAYER MOISTURE AND CONSEQUENTLY BOUNDARY LAYER INSTABILITY AND SOUNDING PARAMETERS. THE HRRR HAS TRENDED TOWARDS A BIT LESS COVERAGE IN ACTIVITY AS WELL...AND INITIATES A BIT LATER IN THE DAY THAN PREVIOUS RUNS. DID DELAY DEVELOPMENT OF ACTIVITY UNTIL LATE MORNING/EARLY AFTERNOON BUT IN GENERAL KEPT INHERITED ISOLD AND SCT POPS FOR THE AFTERNOON TIME FRAME. UPDATE ISSUED AT 730 AM EDT MON SEP 8 2014 TWEAKED THE GRIDS A BIT EARLY THIS MORNING TO FINE TUNE THE SKY COVER AND T/TD PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 345 AM EDT MON SEP 8 2014 07Z SFC ANALYSIS SHOWS COOL AND DRY HIGH PRESSURE SPRAWLED OUT FROM THE OHIO VALLEY THROUGH THE NEW ENGLAND STATES. GENERAL LOW PRESSURE IS FOUND OVER THE DEEP SOUTH AND ALONG THE SOUTHEAST COAST. NOT FAR FROM EAST KENTUCKY IS A STALLED FRONTAL BOUNDARY LURKING JUST TO THE SOUTH. THIS HAS HELPED TO PREVENT THE DRY COMPONENT OF THE HIGH PRESSURE FROM MAKING IT THROUGH ALL OF THE STATE AS DEWPOINTS ALONG THE TENNESSEE BORDER ARE IN THE LOW AND MID 60S WHILE MID AND UPPER 50S EXIST TO THE NORTH. THESE NORTHERN SPOTS ARE ALSO ENJOYING TEMPERATURES DOWN INTO THE MIDDLE AND UPPER 50S...PARTICULARLY IN THE VALLEYS WHERE MOSTLY CLEAR SKIES HAVE ALLOWED FOR DECENT RADIATIONAL COOLING BELOW THE THERMAL INVERSION. MEANWHILE...RIDGES AND LOCATIONS TO THE SOUTH WITH HIGHER DEWPOINTS ARE SEEING TEMPERATURES A FEW DEGREES MORE. A COUPLE LARGE PATCHES OF LOW CLOUDS ARE AFFECTING SOUTHEAST KENTUCKY EARLY THIS MORNING HELPING TO DISRUPT THE FOG FORMATION...THOUGH THERE WILL UNDOUBTEDLY BE PATCHY FOG...LOCALLY DENSE...IN MANY VALLEY LOCATIONS GENERALLY CORRESPONDING TO THE CLEAR SPOTS. THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH ANOTHER POCKET OF ENERGY ROLLING EAST THROUGH GENERALLY FLAT FLOW TODAY...HELPING TO LOWER HEIGHTS LOCALLY AND BRING SOME EXTRA LIFT TO THE AREA. THIS MOVES THROUGH BY EVENING WITH CONTINUED RELATIVELY FAST AND NEARLY ZONAL FLOW INTO THE DAY TUESDAY. LATE IN THE SHORT TERM PORTION OF THE FORECAST HEIGHTS WILL CLIMB A NOTCH AHEAD OF A LARGE AND DEEPENING TROUGH OVER THE ROCKY MOUNTAIN AND HIGH PLAINS STATES. WITH THE MODEL SIMILARITIES HAVE GONE MAINLY WITH A BLEND OF THE HRRR AND NAM12 FOR WX SPECIFICS DURING THE FIRST 12-18 HOURS AND THEN THE 00Z ECMWF/NAM12 THROUGH TUESDAY. SENSIBLE WEATHER WILL FEATURE A CONTINUED COOL AND DRY DAY ACROSS THE FAR NORTHWEST PARTS OF THE AREA WHILE TO THE SOUTHEAST THERE WILL BE MUCH MORE CLOUD COVER ALONG WITH A THREAT FOR SHOWERS THROUGH THE MORNING. BY MIDDAY THUNDER CHANCES WILL PICK UP OWING TO BUILDING INSTABILITY AND THE NEARBY FRONT BEING ACTED UPON BY THE PASSING MID LEVEL SHORT WAVE. THE PCPN THREAT AND SOME OF THE CLOUD COVER WILL RETREAT TO THE EAST LATER TONIGHT WITH ANOTHER NIGHT OF MINOR RIDGE TO VALLEY TEMPERATURE DIFFERENCES AMIDST A NW TO SE STRIATION IN DEWPOINTS. DUE TO THIS ANTICIPATE PATCHY VALLEY FOG AFTER MIDNIGHT FOR MOST LOCATIONS...PARTICULARLY ONES THAT MANAGE TO SEE ANY RAIN DURING THE DAY AND EVENING. TUESDAY WILL BE QUIET AND DRY...BUT A TAD WARMER WHILE THE DEVELOPING LOW TO THE EAST STARTS TO LIFT NORTH ALONG THE SOUTH EAST ATLANTIC SEABOARD. STARTED WITH THE CONSSHORT FOR T...TD...AND WINDS...THROUGH THE FIRST 24 HOURS FOLLOWED BY THE SUPERBLEND UNTIL 00Z WED. PER USUAL...MADE MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS TONIGHT. AS FOR POPS...ENDED UP CLOSER TO THE LOWER MAV GUIDANCE TODAY AND SIMILAR TO A BLEND OF THE RATHER LOW NUMBERS THEREAFTER THROUGH THE REMAINDER OF THE SHORT TERM FORECAST. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 310 AM EDT MON SEP 8 2014 THE MODELS REMAIN IN GOOD AGREEMENT IN THE LONG TERM...WITH A LARGE RIDGE OF HIGH PRESSURE ALOFT INFLUENCING THE WEATHER OF EASTERN KENTUCKY TO BEGIN THE PERIOD. DRY WEATHER SHOULD BE ON TAP TUESDAY NIGHT INTO EARLY WEDNESDAY AFTERNOON AS HIGH PRESSURE REMAINS IN CONTROL. HOWEVER...THIS UPPER RIDGE WILL BE DISPLACED AS DEEP AREA OF LOW PRESSURE...BOTH ALOFT AND AT THE SURFACE...COMES TOGETHER OVER THE NORTHERN PLAINS AND BEGINS TO PUSH ACROSS THE NORTHERN MISSISSIPPI VALLEY ON WEDNESDAY. THE SURFACE COLD FRONT ASSOCIATED WITH THIS POTENT SYSTEM WILL BRING UNSETTLED WEATHER TO THE AREA WEDNESDAY NIGHT AND THURSDAY. THE PRIMARY CONCERN WITH THIS WEATHER SYSTEM WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. THE MODELS HAVE THE FRONT SLOWING DOWN AND NEARLY STALLING ACROSS OUR AREA ON THURSDAY. SHOWERS AND STORMS ARE EXPECTED TO FIRE ALL ALONG THE BOUNDARY AS LARGE AMOUNTS OF WARM MOIST AIR OFF THE GULF OF MEXICO IS CARRIED NORTHWARD INTO THE BOUNDARY ON SOUTHERLY WINDS. THE BEST CHANCE FOR RAIN LOOKS TO BE FROM LATE THURSDAY MORNING THROUGH LATE THURSDAY AFTERNOON WHEN MOISTURE FLOW INTO THE FRONTAL ZONE IS AT ITS PEAK. THERE WILL ALSO BE THE POTENTIAL FOR A FEW STRONG THUNDERSTORMS ON THURSDAY AS THE FRONT MOVES THROUGH AS THERE WILL BE STRONG DYNAMICS ASSOCIATED WITH THE BOUNDARY AND ITS PARENT UPPER LEVEL SYSTEM. THUNDERSTORMS SHOULD THEN GIVE WAY TO RAIN SHOWER BEHIND THE FRONT THURSDAY NIGHT AS THE COOLER AIR MOVES IN BEHIND THE FRONT. THE FRONT IS EXPECTED TO EVENTUALLY CLEAR THE AREA LATE THURSDAY NIGHT INTO EARLY FRIDAY MORNING...AS A LARGE RIDGE OF CANADIAN HIGH PRESSURE PUSHES IT OFF TO OUR EAST. THIS AREA OF HIGH PRESSURE WILL BRING A SIGNIFICANT PATTERN CHANGE TO THE MAJORITY OF THE CONUS EAST OF THE ROCKY MOUNTAINS FROM FRIDAY ONWARD. AFTER SLIGHTLY ABOVE NORMAL TEMPERATURES TUESDAY NIGHT AND WEDNESDAY...A PERIOD OF UNSEASONABLE COOLING WILL BE OCCURRING. HIGHS ON WEDNESDAY ARE EXPECTED TO TOP OUT IN THE MID TO UPPER 80S AS SOUTHERLY WINDS BRING WARM MOIST AIR FROM THE GULF OF MEXICO INTO THE REGION. ONCE THE FRONT ARRIVES ON THURSDAY...WIDESPREAD CLOUD COVER AND PRECIPITATION WILL KEEP TEMPERATURES WELL BELOW NORMAL...WITH HIGHS ONLY CLIMBING TO AROUND 80 BY THURSDAY AFTERNOON. ONCE THE BOUNDARY HAS CLEARED THE AREA LATE THURSDAY NIGHT...AN INVASION OF COOL AN DRY CANADIAN AIR WILL BEGIN TO OCCUR. WITH WINDS SHIFTING TO THE NORTH BEHIND THE FRONT...TEMPERATURES WILL BE HARD PRESSED TO CLIMB INTO THE MID 70S ON FRIDAY. THE COOL WEATHER WILL THEN PERSIST THROUGH THE WEEKEND AS THE RIDGE OF HIGH PRESSURE BECOMES MORE FIRMLY ESTABLISHED. HIGH TEMPERATURES ON SATURDAY ARE EXPECTED TO ONLY CLIMB TO AROUND 70 WITH HIGHS ON SUNDAY ONLY WARMING INTO THE LOW 70S. OVERNIGHT LOWS IN THE 50S ARE EXPECTED AREA WIDE FRIDAY AND SATURDAY NIGHT AS THE COOL CANADIAN AIR POURS INTO THE REGION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 750 AM EDT MON SEP 8 2014 A LOW CLOUD DECK REMAINS IN PLACE OVER MUCH OF EAST KENTUCKY WITH STILL SOME WESTWARD EXPANSION NOTED IN THE SATELLITE TRENDS. THESE CLOUDS ARE GENERALLY IN THE MVFR RANGE FOR CIGS...BUT THERE ARE AREAS OF MUCH LOWER CIGS DOWN TO LIFR IN THE SOUTH ALONG WITH LOW VIS FROM FOG. ISOLATED TO SCATTERED RAIN SHOWERS ARE EXPECTED TO REDEVELOP... MAINLY EAST OF JKL...BY MID MORNING AND PERSISTING INTO THE AFTERNOON. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT AS WELL THROUGH THE EARLY EVENING HOURS. HAVE A VCTS FOR THIS IN THE ALL THE TAFS EXCEPT SYM. WINDS THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE ACROSS THE FORECAST AREA. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...RAY SHORT TERM...GREIF LONG TERM...AR AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
750 AM EDT MON SEP 8 2014 .UPDATE... ISSUED AT 730 AM EDT MON SEP 8 2014 TWEAKED THE GRIDS A BIT EARLY THIS MORNING TO FINE TUNE THE SKY COVER AND T/TD PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 345 AM EDT MON SEP 8 2014 07Z SFC ANALYSIS SHOWS COOL AND DRY HIGH PRESSURE SPRAWLED OUT FROM THE OHIO VALLEY THROUGH THE NEW ENGLAND STATES. GENERAL LOW PRESSURE IS FOUND OVER THE DEEP SOUTH AND ALONG THE SOUTHEAST COAST. NOT FAR FROM EAST KENTUCKY IS A STALLED FRONTAL BOUNDARY LURKING JUST TO THE SOUTH. THIS HAS HELPED TO PREVENT THE DRY COMPONENT OF THE HIGH PRESSURE FROM MAKING IT THROUGH ALL OF THE STATE AS DEWPOINTS ALONG THE TENNESSEE BORDER ARE IN THE LOW AND MID 60S WHILE MID AND UPPER 50S EXIST TO THE NORTH. THESE NORTHERN SPOTS ARE ALSO ENJOYING TEMPERATURES DOWN INTO THE MIDDLE AND UPPER 50S...PARTICULARLY IN THE VALLEYS WHERE MOSTLY CLEAR SKIES HAVE ALLOWED FOR DECENT RADIATIONAL COOLING BELOW THE THERMAL INVERSION. MEANWHILE...RIDGES AND LOCATIONS TO THE SOUTH WITH HIGHER DEWPOINTS ARE SEEING TEMPERATURES A FEW DEGREES MORE. A COUPLE LARGE PATCHES OF LOW CLOUDS ARE AFFECTING SOUTHEAST KENTUCKY EARLY THIS MORNING HELPING TO DISRUPT THE FOG FORMATION...THOUGH THERE WILL UNDOUBTEDLY BE PATCHY FOG...LOCALLY DENSE...IN MANY VALLEY LOCATIONS GENERALLY CORRESPONDING TO THE CLEAR SPOTS. THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH ANOTHER POCKET OF ENERGY ROLLING EAST THROUGH GENERALLY FLAT FLOW TODAY...HELPING TO LOWER HEIGHTS LOCALLY AND BRING SOME EXTRA LIFT TO THE AREA. THIS MOVES THROUGH BY EVENING WITH CONTINUED RELATIVELY FAST AND NEARLY ZONAL FLOW INTO THE DAY TUESDAY. LATE IN THE SHORT TERM PORTION OF THE FORECAST HEIGHTS WILL CLIMB A NOTCH AHEAD OF A LARGE AND DEEPENING TROUGH OVER THE ROCKY MOUNTAIN AND HIGH PLAINS STATES. WITH THE MODEL SIMILARITIES HAVE GONE MAINLY WITH A BLEND OF THE HRRR AND NAM12 FOR WX SPECIFICS DURING THE FIRST 12-18 HOURS AND THEN THE 00Z ECMWF/NAM12 THROUGH TUESDAY. SENSIBLE WEATHER WILL FEATURE A CONTINUED COOL AND DRY DAY ACROSS THE FAR NORTHWEST PARTS OF THE AREA WHILE TO THE SOUTHEAST THERE WILL BE MUCH MORE CLOUD COVER ALONG WITH A THREAT FOR SHOWERS THROUGH THE MORNING. BY MIDDAY THUNDER CHANCES WILL PICK UP OWING TO BUILDING INSTABILITY AND THE NEARBY FRONT BEING ACTED UPON BY THE PASSING MID LEVEL SHORT WAVE. THE PCPN THREAT AND SOME OF THE CLOUD COVER WILL RETREAT TO THE EAST LATER TONIGHT WITH ANOTHER NIGHT OF MINOR RIDGE TO VALLEY TEMPERATURE DIFFERENCES AMIDST A NW TO SE STRIATION IN DEWPOINTS. DUE TO THIS ANTICIPATE PATCHY VALLEY FOG AFTER MIDNIGHT FOR MOST LOCATIONS...PARTICULARLY ONES THAT MANAGE TO SEE ANY RAIN DURING THE DAY AND EVENING. TUESDAY WILL BE QUIET AND DRY...BUT A TAD WARMER WHILE THE DEVELOPING LOW TO THE EAST STARTS TO LIFT NORTH ALONG THE SOUTH EAST ATLANTIC SEABOARD. STARTED WITH THE CONSSHORT FOR T...TD...AND WINDS...THROUGH THE FIRST 24 HOURS FOLLOWED BY THE SUPERBLEND UNTIL 00Z WED. PER USUAL...MADE MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS TONIGHT. AS FOR POPS...ENDED UP CLOSER TO THE LOWER MAV GUIDANCE TODAY AND SIMILAR TO A BLEND OF THE RATHER LOW NUMBERS THEREAFTER THROUGH THE REMAINDER OF THE SHORT TERM FORECAST. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 310 AM EDT MON SEP 8 2014 THE MODELS REMAIN IN GOOD AGREEMENT IN THE LONG TERM...WITH A LARGE RIDGE OF HIGH PRESSURE ALOFT INFLUENCING THE WEATHER OF EASTERN KENTUCKY TO BEGIN THE PERIOD. DRY WEATHER SHOULD BE ON TAP TUESDAY NIGHT INTO EARLY WEDNESDAY AFTERNOON AS HIGH PRESSURE REMAINS IN CONTROL. HOWEVER...THIS UPPER RIDGE WILL BE DISPLACED AS DEEP AREA OF LOW PRESSURE...BOTH ALOFT AND AT THE SURFACE...COMES TOGETHER OVER THE NORTHERN PLAINS AND BEGINS TO PUSH ACROSS THE NORTHERN MISSISSIPPI VALLEY ON WEDNESDAY. THE SURFACE COLD FRONT ASSOCIATED WITH THIS POTENT SYSTEM WILL BRING UNSETTLED WEATHER TO THE AREA WEDNESDAY NIGHT AND THURSDAY. THE PRIMARY CONCERN WITH THIS WEATHER SYSTEM WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. THE MODELS HAVE THE FRONT SLOWING DOWN AND NEARLY STALLING ACROSS OUR AREA ON THURSDAY. SHOWERS AND STORMS ARE EXPECTED TO FIRE ALL ALONG THE BOUNDARY AS LARGE AMOUNTS OF WARM MOIST AIR OFF THE GULF OF MEXICO IS CARRIED NORTHWARD INTO THE BOUNDARY ON SOUTHERLY WINDS. THE BEST CHANCE FOR RAIN LOOKS TO BE FROM LATE THURSDAY MORNING THROUGH LATE THURSDAY AFTERNOON WHEN MOISTURE FLOW INTO THE FRONTAL ZONE IS AT ITS PEAK. THERE WILL ALSO BE THE POTENTIAL FOR A FEW STRONG THUNDERSTORMS ON THURSDAY AS THE FRONT MOVES THROUGH AS THERE WILL BE STRONG DYNAMICS ASSOCIATED WITH THE BOUNDARY AND ITS PARENT UPPER LEVEL SYSTEM. THUNDERSTORMS SHOULD THEN GIVE WAY TO RAIN SHOWER BEHIND THE FRONT THURSDAY NIGHT AS THE COOLER AIR MOVES IN BEHIND THE FRONT. THE FRONT IS EXPECTED TO EVENTUALLY CLEAR THE AREA LATE THURSDAY NIGHT INTO EARLY FRIDAY MORNING...AS A LARGE RIDGE OF CANADIAN HIGH PRESSURE PUSHES IT OFF TO OUR EAST. THIS AREA OF HIGH PRESSURE WILL BRING A SIGNIFICANT PATTERN CHANGE TO THE MAJORITY OF THE CONUS EAST OF THE ROCKY MOUNTAINS FROM FRIDAY ONWARD. AFTER SLIGHTLY ABOVE NORMAL TEMPERATURES TUESDAY NIGHT AND WEDNESDAY...A PERIOD OF UNSEASONABLE COOLING WILL BE OCCURRING. HIGHS ON WEDNESDAY ARE EXPECTED TO TOP OUT IN THE MID TO UPPER 80S AS SOUTHERLY WINDS BRING WARM MOIST AIR FROM THE GULF OF MEXICO INTO THE REGION. ONCE THE FRONT ARRIVES ON THURSDAY...WIDESPREAD CLOUD COVER AND PRECIPITATION WILL KEEP TEMPERATURES WELL BELOW NORMAL...WITH HIGHS ONLY CLIMBING TO AROUND 80 BY THURSDAY AFTERNOON. ONCE THE BOUNDARY HAS CLEARED THE AREA LATE THURSDAY NIGHT...AN INVASION OF COOL AN DRY CANADIAN AIR WILL BEGIN TO OCCUR. WITH WINDS SHIFTING TO THE NORTH BEHIND THE FRONT...TEMPERATURES WILL BE HARD PRESSED TO CLIMB INTO THE MID 70S ON FRIDAY. THE COOL WEATHER WILL THEN PERSIST THROUGH THE WEEKEND AS THE RIDGE OF HIGH PRESSURE BECOMES MORE FIRMLY ESTABLISHED. HIGH TEMPERATURES ON SATURDAY ARE EXPECTED TO ONLY CLIMB TO AROUND 70 WITH HIGHS ON SUNDAY ONLY WARMING INTO THE LOW 70S. OVERNIGHT LOWS IN THE 50S ARE EXPECTED AREA WIDE FRIDAY AND SATURDAY NIGHT AS THE COOL CANADIAN AIR POURS INTO THE REGION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 750 AM EDT MON SEP 8 2014 A LOW CLOUD DECK REMAINS IN PLACE OVER MUCH OF EAST KENTUCKY WITH STILL SOME WESTWARD EXPANSION NOTED IN THE SATELLITE TRENDS. THESE CLOUDS ARE GENERALLY IN THE MVFR RANGE FOR CIGS...BUT THERE ARE AREAS OF MUCH LOWER CIGS DOWN TO LIFR IN THE SOUTH ALONG WITH LOW VIS FROM FOG. ISOLATED TO SCATTERED RAIN SHOWERS ARE EXPECTED TO REDEVELOP... MAINLY EAST OF JKL...BY MID MORNING AND PERSISTING INTO THE AFTERNOON. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT AS WELL THROUGH THE EARLY EVENING HOURS. HAVE A VCTS FOR THIS IN THE ALL THE TAFS EXCEPT SYM. WINDS THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE ACROSS THE FORECAST AREA. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...GREIF LONG TERM...AR AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
345 AM EDT MON SEP 8 2014 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 345 AM EDT MON SEP 8 2014 07Z SFC ANALYSIS SHOWS COOL AND DRY HIGH PRESSURE SPRAWLED OUT FROM THE OHIO VALLEY THROUGH THE NEW ENGLAND STATES. GENERAL LOW PRESSURE IS FOUND OVER THE DEEP SOUTH AND ALONG THE SOUTHEAST COAST. NOT FAR FROM EAST KENTUCKY IS A STALLED FRONTAL BOUNDARY LURKING JUST TO THE SOUTH. THIS HAS HELPED TO PREVENT THE DRY COMPONENT OF THE HIGH PRESSURE FROM MAKING IT THROUGH ALL OF THE STATE AS DEWPOINTS ALONG THE TENNESSEE BORDER ARE IN THE LOW AND MID 60S WHILE MID AND UPPER 50S EXIST TO THE NORTH. THESE NORTHERN SPOTS ARE ALSO ENJOYING TEMPERATURES DOWN INTO THE MIDDLE AND UPPER 50S...PARTICULARLY IN THE VALLEYS WHERE MOSTLY CLEAR SKIES HAVE ALLOWED FOR DECENT RADIATIONAL COOLING BELOW THE THERMAL INVERSION. MEANWHILE...RIDGES AND LOCATIONS TO THE SOUTH WITH HIGHER DEWPOINTS ARE SEEING TEMPERATURES A FEW DEGREES MORE. A COUPLE LARGE PATCHES OF LOW CLOUDS ARE AFFECTING SOUTHEAST KENTUCKY EARLY THIS MORNING HELPING TO DISRUPT THE FOG FORMATION...THOUGH THERE WILL UNDOUBTEDLY BE PATCHY FOG...LOCALLY DENSE...IN MANY VALLEY LOCATIONS GENERALLY CORRESPONDING TO THE CLEAR SPOTS. THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH ANOTHER POCKET OF ENERGY ROLLING EAST THROUGH GENERALLY FLAT FLOW TODAY...HELPING TO LOWER HEIGHTS LOCALLY AND BRING SOME EXTRA LIFT TO THE AREA. THIS MOVES THROUGH BY EVENING WITH CONTINUED RELATIVELY FAST AND NEARLY ZONAL FLOW INTO THE DAY TUESDAY. LATE IN THE SHORT TERM PORTION OF THE FORECAST HEIGHTS WILL CLIMB A NOTCH AHEAD OF A LARGE AND DEEPENING TROUGH OVER THE ROCKY MOUNTAIN AND HIGH PLAINS STATES. WITH THE MODEL SIMILARITIES HAVE GONE MAINLY WITH A BLEND OF THE HRRR AND NAM12 FOR WX SPECIFICS DURING THE FIRST 12-18 HOURS AND THEN THE 00Z ECMWF/NAM12 THROUGH TUESDAY. SENSIBLE WEATHER WILL FEATURE A CONTINUED COOL AND DRY DAY ACROSS THE FAR NORTHWEST PARTS OF THE AREA WHILE TO THE SOUTHEAST THERE WILL BE MUCH MORE CLOUD COVER ALONG WITH A THREAT FOR SHOWERS THROUGH THE MORNING. BY MIDDAY THUNDER CHANCES WILL PICK UP OWING TO BUILDING INSTABILITY AND THE NEARBY FRONT BEING ACTED UPON BY THE PASSING MID LEVEL SHORT WAVE. THE PCPN THREAT AND SOME OF THE CLOUD COVER WILL RETREAT TO THE EAST LATER TONIGHT WITH ANOTHER NIGHT OF MINOR RIDGE TO VALLEY TEMPERATURE DIFFERENCES AMIDST A NW TO SE STRIATION IN DEWPOINTS. DUE TO THIS ANTICIPATE PATCHY VALLEY FOG AFTER MIDNIGHT FOR MOST LOCATIONS...PARTICULARLY ONES THAT MANAGE TO SEE ANY RAIN DURING THE DAY AND EVENING. TUESDAY WILL BE QUIET AND DRY...BUT A TAD WARMER WHILE THE DEVELOPING LOW TO THE EAST STARTS TO LIFT NORTH ALONG THE SOUTH EAST ATLANTIC SEABOARD. STARTED WITH THE CONSSHORT FOR T...TD...AND WINDS...THROUGH THE FIRST 24 HOURS FOLLOWED BY THE SUPERBLEND UNTIL 00Z WED. PER USUAL...MADE MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS TONIGHT. AS FOR POPS...ENDED UP CLOSER TO THE LOWER MAV GUIDANCE TODAY AND SIMILAR TO A BLEND OF THE RATHER LOW NUMBERS THEREAFTER THROUGH THE REMAINDER OF THE SHORT TERM FORECAST. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 310 AM EDT MON SEP 8 2014 THE MODELS REMAIN IN GOOD AGREEMENT IN THE LONG TERM...WITH A LARGE RIDGE OF HIGH PRESSURE ALOFT INFLUENCING THE WEATHER OF EASTERN KENTUCKY TO BEGIN THE PERIOD. DRY WEATHER SHOULD BE ON TAP TUESDAY NIGHT INTO EARLY WEDNESDAY AFTERNOON AS HIGH PRESSURE REMAINS IN CONTROL. HOWEVER...THIS UPPER RIDGE WILL BE DISPLACED AS DEEP AREA OF LOW PRESSURE...BOTH ALOFT AND AT THE SURFACE...COMES TOGETHER OVER THE NORTHERN PLAINS AND BEGINS TO PUSH ACROSS THE NORTHERN MISSISSIPPI VALLEY ON WEDNESDAY. THE SURFACE COLD FRONT ASSOCIATED WITH THIS POTENT SYSTEM WILL BRING UNSETTLED WEATHER TO THE AREA WEDNESDAY NIGHT AND THURSDAY. THE PRIMARY CONCERN WITH THIS WEATHER SYSTEM WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. THE MODELS HAVE THE FRONT SLOWING DOWN AND NEARLY STALLING ACROSS OUR AREA ON THURSDAY. SHOWERS AND STORMS ARE EXPECTED TO FIRE ALL ALONG THE BOUNDARY AS LARGE AMOUNTS OF WARM MOIST AIR OFF THE GULF OF MEXICO IS CARRIED NORTHWARD INTO THE BOUNDARY ON SOUTHERLY WINDS. THE BEST CHANCE FOR RAIN LOOKS TO BE FROM LATE THURSDAY MORNING THROUGH LATE THURSDAY AFTERNOON WHEN MOISTURE FLOW INTO THE FRONTAL ZONE IS AT ITS PEAK. THERE WILL ALSO BE THE POTENTIAL FOR A FEW STRONG THUNDERSTORMS ON THURSDAY AS THE FRONT MOVES THROUGH AS THERE WILL BE STRONG DYNAMICS ASSOCIATED WITH THE BOUNDARY AND ITS PARENT UPPER LEVEL SYSTEM. THUNDERSTORMS SHOULD THEN GIVE WAY TO RAIN SHOWER BEHIND THE FRONT THURSDAY NIGHT AS THE COOLER AIR MOVES IN BEHIND THE FRONT. THE FRONT IS EXPECTED TO EVENTUALLY CLEAR THE AREA LATE THURSDAY NIGHT INTO EARLY FRIDAY MORNING...AS A LARGE RIDGE OF CANADIAN HIGH PRESSURE PUSHES IT OFF TO OUR EAST. THIS AREA OF HIGH PRESSURE WILL BRING A SIGNIFICANT PATTERN CHANGE TO THE MAJORITY OF THE CONUS EAST OF THE ROCKY MOUNTAINS FROM FRIDAY ONWARD. AFTER SLIGHTLY ABOVE NORMAL TEMPERATURES TUESDAY NIGHT AND WEDNESDAY...A PERIOD OF UNSEASONABLE COOLING WILL BE OCCURRING. HIGHS ON WEDNESDAY ARE EXPECTED TO TOP OUT IN THE MID TO UPPER 80S AS SOUTHERLY WINDS BRING WARM MOIST AIR FROM THE GULF OF MEXICO INTO THE REGION. ONCE THE FRONT ARRIVES ON THURSDAY...WIDESPREAD CLOUD COVER AND PRECIPITATION WILL KEEP TEMPERATURES WELL BELOW NORMAL...WITH HIGHS ONLY CLIMBING TO AROUND 80 BY THURSDAY AFTERNOON. ONCE THE BOUNDARY HAS CLEARED THE AREA LATE THURSDAY NIGHT...AN INVASION OF COOL AN DRY CANADIAN AIR WILL BEGIN TO OCCUR. WITH WINDS SHIFTING TO THE NORTH BEHIND THE FRONT...TEMPERATURES WILL BE HARD PRESSED TO CLIMB INTO THE MID 70S ON FRIDAY. THE COOL WEATHER WILL THEN PERSIST THROUGH THE WEEKEND AS THE RIDGE OF HIGH PRESSURE BECOMES MORE FIRMLY ESTABLISHED. HIGH TEMPERATURES ON SATURDAY ARE EXPECTED TO ONLY CLIMB TO AROUND 70 WITH HIGHS ON SUNDAY ONLY WARMING INTO THE LOW 70S. OVERNIGHT LOWS IN THE 50S ARE EXPECTED AREA WIDE FRIDAY AND SATURDAY NIGHT AS THE COOL CANADIAN AIR POURS INTO THE REGION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 230 AM EDT MON SEP 8 2014 A LOW CLOUD DECK IS HOLDING ON OVER FAR SOUTHEAST KENTUCKY WITH SOME WESTWARD PUSH NOTED IN THE SATELLITE TRENDS. THESE CLOUDS ARE GENERALLY IN THE MVFR RANGE FOR CIGS. HOWEVER...THEY ARE HELPING TO KEEP THE FOG AT BAY FOR MANY OF THE SITES IN THE EAST THOUGH IT CANNOT BE COMPLETELY RULED OUT...ESPECIALLY IF THERE ARE ANY BREAKS. WILL CONTINUE THE FORECAST FOR LOWERING CIGS AND POORER AVIATION CONDITIONS THROUGH DAWN. ISOLATED TO SCATTERED RAIN SHOWERS ARE EXPECTED TO REDEVELOP...MAINLY EAST OF JKL...TOWARD MORNING PERSISTING INTO THE DAY. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT MONDAY AFTERNOON AND INTO THE EARLY EVENING HOURS...AS WELL. HAVE ADDED A VCTS FOR THIS IN THE ALL THE TAFS EXCEPT SYM. WINDS THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE ACROSS THE FORECAST AREA. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GREIF LONG TERM...AR AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1148 PM EDT TUE SEP 9 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 344 PM EDT TUE SEP 9 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A SPLIT FLOW PATTERN WITH A DEVELOPING MID/UPPER LEVEL TROUGH OVER THE WRN CONUS. THE TAIL OF AN ELONGATED SHORTWAVE TROUGH MOVING THROUGH NRN ONTARIO WAS DRAGGING A COLD FRONT SLOWLY SOUTH INTO WRN LAKE SUPERIOR. A VIGOROUS SRN STREAM SHRTWV MOVING IN THE CNTRL PLAINS WILL SUPPORT DEVELOPMENT OF A SFC LOW THAT WILL MOVE INTO THE WRN LAKES WED. EVEN WITH LAKE BREEZE ONSHORE WINDS INTO WRN UPPER MI...LOW LEVEL CONV HAS NOT BEEN STRONG ENOUGH TO OVERCOME CAPPING WITH 800-750 MB TEMPS NEAR 12C...PER RUC. OTHERWISE...ABUNDANT CU PREVAILED ACROSS THE WEST HALF OF UPPER MI WHILE MORE STABLE AIR OFF OF LAKE MI HAS KEPT SKIES MOSTLY CLEAR OVER THE EAST. THE POTENTIAL REMAINS FOR SOME SHRA/TSRA THIS EVENING AS THE FRONTAL BOUNDARY MOVES THROUGH WRN UPPER MI. HOWEVER...COVERAGE SHOULD LIMITED WITH ONLY LOWER END CHANCE POPS GIVEN THE STRENGTH OF THE CAPPING. AS THE PLAINS SHRTWV MOVES TOWARD THE AREA AND THE SFC LOW DEEPENS...300-310 ISENTROPIC ASCENT ALONG WITH 800-600 MB FGEN WILL STRENGTHEN AND SUPPORT AN EXPANDING AREA OF MODERATE TO HEAVY RAIN FROM NW/N WI INTO WRN UPPER MI BY LATE EVENING AND INTO CNTRL UPPER MI LATE TONIGHT. STRONG MID/UPPER LEVEL DYNAMICS WITH A COUPLED UPPER LEVEL JET STRUCTURE AND STRONG QVECTOR CONV WILL SUPPORT A LARGE AREA OF RAIN ACROSS THE CWA WED. SOME MODEL UNCERTAINTY REMAINS AS THE NAM REMAINS MUCH DEEPER AND FARTHER TO THE NW THAN MODELS CONSENSUS AND THE GFS FASTER AND ALONG THE SOUTHERN ENVELOPE OF MODEL SPREAD. FAVORED THE MORE CONSISTENT ECMWF AND REGIONAL GEM WITH THE LOW PATH TO NEAR GRB BY 18Z AND THE STRAITS BY 00Z/THU. VERY STRONG 850 MB MOISTURE INFLOW...UPPER LEVEL AND 800-600 MB FGEN EVEN WITHOUT TSRA WILL BRING THE POTENTIAL FOR A PERIOD OF HEAVY RAIN...ESPECIALLY BTWN 09Z-18Z. UNCERTAINTY REMAINS ON THE IMPACT OF UPSTREAM CONVECTION OVER IA INTO SRN WI ON THE EVOLUTION OF THE 850-700 MB FRONTAL BOUNDARY AND MOISTURE INFLOW TO THE NORTH. HOWEVER...THE POTENTIAL REMAINS FOR QPF IN THE 1.5 INCH TO 2.0 INCH RANGE...WITH LOCALLY HIGHER AMOUNTS AOA 3 INCHES. SO THE FLOOD WATCH WILL REMAINS IN EFFECT. NE WINDS VEERING TO THE NNE WILL ALSO INCREASE WITH GUSTS LIKELY IN INTO THE 40-50 KNOT RANGE BY TO LATE AFTERNOON OVER THE KEWEENAW...ESPECIALLY FOR LOCATIONS FAVORED BY NNE FLOW SUCH AS COPPER HARBOR. AN ADVISORY WILL LIKELY BE NEEDED. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 305 PM EDT TUE SEP 9 2014 SOME DISCREPANCIES BETWEEN MODELS AT 00Z THU. TWO EXTREMES WITH THE LOW LOCATION/STRENGTH ARE THE 12Z/09 GFS WITH A 997MB SFC LOW NEAR CENTRAL LAKE HURON AND THE 12Z/09 NAM WITH A 984MB SFC LOW NEAR MUNISING. HARD TO JUMP ON BOARD WITH EITHER OF THESE TWO EXTREMES GIVEN WARM SEASON PROCESSES THAT WILL OCCUR IN THE WARM SECTOR OF THE LOW...BUT THINK A MIDDLE OF THE GROUND APPROACH IS MORE REASONABLE. REGARDLESS...STRONG NLY WINDS WILL BE ONGOING ACROSS THE CWA AT 00Z THU...AND IF THE FARTHER N/STRONGER SOLUTION IS CORRECT...THE WINDS WOULD BE VERY STRONG. THE HIGH EXTREME OF THE NAM EVEN HAS 925MB WINDS UP TO 70KTS /POSSIBLY RESULTING IN SFC GUSTS OF 55-70KTS/ BETWEEN 00Z AND 06Z THU...WHICH CAN NOT BE RULED OUT...BUT MORE MODERATE WINDS ARE EXPECTED. BY 06Z...EVEN THE NAM HAS THE LOW E OF LAKE SUPERIOR...WITH OTHER MODELS FARTHER SE. BY 12Z THU...925MB WINDS ARE EXPECTED TO BE BELOW 30KTS...WITH THE PRESSURE GRADIENT RELAXING FASTER DURING THE DAY THU. MOST OF THE PRECIP WED NIGHT INTO THU WILL BE DUE TO WRAP AROUND MOISTURE AND UPSLOPE FLOW AND SHOULD GRADUALLY DIMINISH INTO THU EVENING. THU LOOKS TO BE COLDEST DAY IN A WHILE AREA WIDE AS CLOUDY CONDITIONS PERSIST BEHIND THE SYSTEM AND 850MB TEMPS WILL BE -2C TO 1C...RESULTING IN HIGH TEMPS FROM THE UPPER 40S INTERIOR W TO THE LOW 50S ELSEWHERE...AND THE CONTINUED BREEZY WINDS WILL ONLY MAKE IT FEEL COOLER. GIVEN THE COLD TEMPS...THINK BELOW FREEZING MIN TEMPS THU NIGHT LOOK FAIRLY LIKELY OVER THE INTERIOR W...WITH A MORE CONDITIONAL CHANCE FRI NIGHT DEPENDING ON THE CLOUD COVER. NOT SURE ABOUT PRECIP CHANCES FRI INTO FRI INTO SAT AS MODELS POINT TO AN UPPER LEVEL DISTURBANCE MOVING INTO THE REGION OVER SFC HIGH PRESSURE. ONLY LOW END POPS WILL REMAIN IN THE FORECAST AS THE ECMWF IS THE ONLY MODEL SHOWING SIGNIFICANT PRECIP ACROSS THE CWA...THE OTHER MODELS HAVE A WEAKER WAVE AND LESS MOISTURE. 850MB TEMPS REMAIN MOSTLY THE SAME THROUGH SAT AT AROUND 0C...BUT CLOUD COVER SHOULD BE LOWER EACH FRI AND ESPECIALLY SAT...SO HIGHS WILL WARM INTO THE MID TO UPPER 50S BE SAT. POSSIBILITY OF ANOTHER WAVE ON SUN AND MAYBE YET ANOTHER ON MON AS A RIDGE BUILDS ACROSS THE WRN CONUS AND A TROUGH ACROSS THE ERN CONUS. EVEN LOWER CONFIDENCE ON PRECIP WITH THESE FEATURES AS MOISTURE WILL BE LIMITED AS THE TRACK/STRENGTH OF THE ENERGY IS UNCERTAIN. TEMPS DO LOOK TO INCREASE BUT WILL REMAIN BELOW NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1148 PM EDT TUE SEP 9 2014 NNE WIND SHIFT BEHIND A COLD FRONT MOVED BROUGHT LIFR CLOUDS INTO IWD/CMX LAST EVENING. A FEW SHRA/TSRA HAVE ALSO POPPED UP ALONG FRONTAL BOUNDARY MAINLY AT IWD. AS A STRONGER DISTURBANCE MOVES NEWD AND THE MOIST LYR DEEPENS...WIDESPREAD RAIN WILL DEVELOP FROM SW TO NE AND KEEPING CONDITIONS LIFR AT IWD/CMX INTO MUCH OF WED. SINCE THE FROPA WL OCCUR LATER AT SAW...THE TRANSITION TO MVFR WILL NOT OCCUR UNTIL AROUND 08Z. BY LATE TONIGHT INTO WED MORNING LIFR CONDITIONS WILL PREVAIL AT SAW AS WELL WITH MODERATE TO OCNLY HEAVY RAIN AND GUSTY NE-N WINDS DEVELOPING BY LATE MORNING/AFTERNOON. NE-N WIND WILL GUST OVER 30 KT AT KCMX AND POSSIBLY AOA 25 KTS AT KSAW AND IWD BY LATE MORNING/MIDDAY WED. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 344 PM EDT TUE SEP 9 2014 THE TROUGH STRETCHED ACROSS W LAKE SUPERIOR WILL DRIFT ACROSS LAKE SUPERIOR THIS EVENING AS LOW PRESSURE APPROACHES FROM THE CENTRAL PLAINS. THE LOW WILL BE OVER E IOWA BY DAYBREAK WEDNESDAY...AND CONTINUE TO PUSH TO NRN LOWER MI BY WED EVENING...BEFORE EXITING INTO QUEBEC ON THURSDAY. NORTHEAST GALES TO AROUND 40KTS WILL BE POSSIBLE WEDNESDAY MORNING OVER W LAKE SUPERIOR...BEFORE SLOWLY EXPANDING TO CENTRAL LAKE SUPERIOR WEDNESDAY EVENING THROUGH THE OVERNIGHT HOURS AS WINDS BACK TO THE NORTH. LARGE HIGH PRESSURE OVER S ALBERTA AND SASKATCHEWAN THURSDAY WILL SINK ACROSS THE N AND CENTRAL PLAINS...WHILE BUILDING A RIDGE ACROSS LAKE SUPERIOR THURSDAY NIGHT THROUGH SATURDAY WITH WINDS GUSTING TO AROUND 20KTS OR LESS. && .HYDROLOGY... ISSUED AT 344 PM EDT TUE SEP 9 2014 RAINFALL TOTALS FROM TONIGHT THROUGH WEDNESDAY NIGHT ACROSS UPPER MI RANGE FROM JUST OVER 1.5 TO LOCALLY 3 INCHES. UNCERTAINTY REMAINS WHERE THE HEAVIER BANDS OF RAIN WILL DEVELOP. HIGHER TOTALS INTO WED NIGHT ARE EXPECTED FOR LOCATIONS IN N CNTRL UPPER MI WHERE STRONG UPSLOPE FLOW WILL BOOST RAINFALL AMOUNTS. THE FLOOD WATCH REMAINS POSTED FOR MUCH OF W AND CENTRAL UPPER MI. EXPECT THE TRADITIONAL URBAN/SMALL STREAM FLOODING TO BE A SIGNIFICANT POSSIBILITY IN THE TYPICAL POOR DRAINAGE AREAS OF ESC IF A PERIOD OF HEAVIER DOWNPOURS DEVELOP WITH RAINFALL RATES CLOSE TO AN 0.5-1.0 INCH PER HOUR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... FLOOD WATCH THROUGH WEDNESDAY EVENING FOR MIZ001>006-009>013-084. LAKE SUPERIOR... GALE WARNING FROM 8 PM WEDNESDAY TO 8 AM EDT THURSDAY FOR LSZ251- 267. GALE WARNING FROM 2 PM WEDNESDAY TO 5 AM EDT THURSDAY FOR LSZ246>250-265-266. GALE WARNING FROM 5 AM WEDNESDAY TO 4 AM EDT THURSDAY FOR LSZ243>245-264. GALE WARNING UNTIL 2 AM EDT /1 AM CDT/ THURSDAY FOR LSZ240>242- 263. GALE WARNING UNTIL 11 PM EDT /10 PM CDT/ WEDNESDAY FOR LSZ162. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...TITUS AVIATION...VOSS MARINE...JLB HYDROLOGY...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
912 PM EDT TUE SEP 9 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 344 PM EDT TUE SEP 9 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A SPLIT FLOW PATTERN WITH A DEVELOPING MID/UPPER LEVEL TROUGH OVER THE WRN CONUS. THE TAIL OF AN ELONGATED SHORTWAVE TROUGH MOVING THROUGH NRN ONTARIO WAS DRAGGING A COLD FRONT SLOWLY SOUTH INTO WRN LAKE SUPERIOR. A VIGOROUS SRN STREAM SHRTWV MOVING IN THE CNTRL PLAINS WILL SUPPORT DEVELOPMENT OF A SFC LOW THAT WILL MOVE INTO THE WRN LAKES WED. EVEN WITH LAKE BREEZE ONSHORE WINDS INTO WRN UPPER MI...LOW LEVEL CONV HAS NOT BEEN STRONG ENOUGH TO OVERCOME CAPPING WITH 800-750 MB TEMPS NEAR 12C...PER RUC. OTHERWISE...ABUNDANT CU PREVAILED ACROSS THE WEST HALF OF UPPER MI WHILE MORE STABLE AIR OFF OF LAKE MI HAS KEPT SKIES MOSTLY CLEAR OVER THE EAST. THE POTENTIAL REMAINS FOR SOME SHRA/TSRA THIS EVENING AS THE FRONTAL BOUNDARY MOVES THROUGH WRN UPPER MI. HOWEVER...COVERAGE SHOULD LIMITED WITH ONLY LOWER END CHANCE POPS GIVEN THE STRENGTH OF THE CAPPING. AS THE PLAINS SHRTWV MOVES TOWARD THE AREA AND THE SFC LOW DEEPENS...300-310 ISENTROPIC ASCENT ALONG WITH 800-600 MB FGEN WILL STRENGTHEN AND SUPPORT AN EXPANDING AREA OF MODERATE TO HEAVY RAIN FROM NW/N WI INTO WRN UPPER MI BY LATE EVENING AND INTO CNTRL UPPER MI LATE TONIGHT. STRONG MID/UPPER LEVEL DYNAMICS WITH A COUPLED UPPER LEVEL JET STRUCTURE AND STRONG QVECTOR CONV WILL SUPPORT A LARGE AREA OF RAIN ACROSS THE CWA WED. SOME MODEL UNCERTAINTY REMAINS AS THE NAM REMAINS MUCH DEEPER AND FARTHER TO THE NW THAN MODELS CONSENSUS AND THE GFS FASTER AND ALONG THE SOUTHERN ENVELOPE OF MODEL SPREAD. FAVORED THE MORE CONSISTENT ECMWF AND REGIONAL GEM WITH THE LOW PATH TO NEAR GRB BY 18Z AND THE STRAITS BY 00Z/THU. VERY STRONG 850 MB MOISTURE INFLOW...UPPER LEVEL AND 800-600 MB FGEN EVEN WITHOUT TSRA WILL BRING THE POTENTIAL FOR A PERIOD OF HEAVY RAIN...ESPECIALLY BTWN 09Z-18Z. UNCERTAINTY REMAINS ON THE IMPACT OF UPSTREAM CONVECTION OVER IA INTO SRN WI ON THE EVOLUTION OF THE 850-700 MB FRONTAL BOUNDARY AND MOISTURE INFLOW TO THE NORTH. HOWEVER...THE POTENTIAL REMAINS FOR QPF IN THE 1.5 INCH TO 2.0 INCH RANGE...WITH LOCALLY HIGHER AMOUNTS AOA 3 INCHES. SO THE FLOOD WATCH WILL REMAINS IN EFFECT. NE WINDS VEERING TO THE NNE WILL ALSO INCREASE WITH GUSTS LIKELY IN INTO THE 40-50 KNOT RANGE BY TO LATE AFTERNOON OVER THE KEWEENAW...ESPECIALLY FOR LOCATIONS FAVORED BY NNE FLOW SUCH AS COPPER HARBOR. AN ADVISORY WILL LIKELY BE NEEDED. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 305 PM EDT TUE SEP 9 2014 SOME DISCREPANCIES BETWEEN MODELS AT 00Z THU. TWO EXTREMES WITH THE LOW LOCATION/STRENGTH ARE THE 12Z/09 GFS WITH A 997MB SFC LOW NEAR CENTRAL LAKE HURON AND THE 12Z/09 NAM WITH A 984MB SFC LOW NEAR MUNISING. HARD TO JUMP ON BOARD WITH EITHER OF THESE TWO EXTREMES GIVEN WARM SEASON PROCESSES THAT WILL OCCUR IN THE WARM SECTOR OF THE LOW...BUT THINK A MIDDLE OF THE GROUND APPROACH IS MORE REASONABLE. REGARDLESS...STRONG NLY WINDS WILL BE ONGOING ACROSS THE CWA AT 00Z THU...AND IF THE FARTHER N/STRONGER SOLUTION IS CORRECT...THE WINDS WOULD BE VERY STRONG. THE HIGH EXTREME OF THE NAM EVEN HAS 925MB WINDS UP TO 70KTS /POSSIBLY RESULTING IN SFC GUSTS OF 55-70KTS/ BETWEEN 00Z AND 06Z THU...WHICH CAN NOT BE RULED OUT...BUT MORE MODERATE WINDS ARE EXPECTED. BY 06Z...EVEN THE NAM HAS THE LOW E OF LAKE SUPERIOR...WITH OTHER MODELS FARTHER SE. BY 12Z THU...925MB WINDS ARE EXPECTED TO BE BELOW 30KTS...WITH THE PRESSURE GRADIENT RELAXING FASTER DURING THE DAY THU. MOST OF THE PRECIP WED NIGHT INTO THU WILL BE DUE TO WRAP AROUND MOISTURE AND UPSLOPE FLOW AND SHOULD GRADUALLY DIMINISH INTO THU EVENING. THU LOOKS TO BE COLDEST DAY IN A WHILE AREA WIDE AS CLOUDY CONDITIONS PERSIST BEHIND THE SYSTEM AND 850MB TEMPS WILL BE -2C TO 1C...RESULTING IN HIGH TEMPS FROM THE UPPER 40S INTERIOR W TO THE LOW 50S ELSEWHERE...AND THE CONTINUED BREEZY WINDS WILL ONLY MAKE IT FEEL COOLER. GIVEN THE COLD TEMPS...THINK BELOW FREEZING MIN TEMPS THU NIGHT LOOK FAIRLY LIKELY OVER THE INTERIOR W...WITH A MORE CONDITIONAL CHANCE FRI NIGHT DEPENDING ON THE CLOUD COVER. NOT SURE ABOUT PRECIP CHANCES FRI INTO FRI INTO SAT AS MODELS POINT TO AN UPPER LEVEL DISTURBANCE MOVING INTO THE REGION OVER SFC HIGH PRESSURE. ONLY LOW END POPS WILL REMAIN IN THE FORECAST AS THE ECMWF IS THE ONLY MODEL SHOWING SIGNIFICANT PRECIP ACROSS THE CWA...THE OTHER MODELS HAVE A WEAKER WAVE AND LESS MOISTURE. 850MB TEMPS REMAIN MOSTLY THE SAME THROUGH SAT AT AROUND 0C...BUT CLOUD COVER SHOULD BE LOWER EACH FRI AND ESPECIALLY SAT...SO HIGHS WILL WARM INTO THE MID TO UPPER 50S BE SAT. POSSIBILITY OF ANOTHER WAVE ON SUN AND MAYBE YET ANOTHER ON MON AS A RIDGE BUILDS ACROSS THE WRN CONUS AND A TROUGH ACROSS THE ERN CONUS. EVEN LOWER CONFIDENCE ON PRECIP WITH THESE FEATURES AS MOISTURE WILL BE LIMITED AS THE TRACK/STRENGTH OF THE ENERGY IS UNCERTAIN. TEMPS DO LOOK TO INCREASE BUT WILL REMAIN BELOW NORMAL. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 904 PM EDT TUE SEP 9 2014 A COLD FRONT MOVED THROUGH IWD/CMX EARLY THIS EVENING WITH A WIND SHIFT TO THE NNE BEHIND THE FRONTAL PASSAGE. THE ARRIVAL OF SOME SHALLOW COOL AIR OFF LAKE SUPERIOR SHOULD BRING SOME MVFR CLDS INTO THOSE LOCATIONS THIS EVENING WITH SOME ISOLD SHRA/TSRA AT KIWD. AS A STRONGER DISTURBANCE MOVES NEWD AND THE MOIST LYR DEEPENS...RAIN WILL DEVELOP FROM SW TO NE AND CAUSE CONDITIONS AT IWD/CMX TO DROP TO IFR BY OVERNIGHT. SINCE THE FROPA WL OCCUR LATER AT SAW...THE TRANSITION TO MVFR WILL NOT OCCUR UNTIL AFT 06Z. BY LATE TONIGHT INTO WED MORNING LIFR CONDITIONS WILL PREVAIL AT THE TAF SITES WITH MODERATE TO OCNLY HEAVY RAIN AND GUSTY NE-N WINDS DEVELOPING BY LATE MORNING/AFTERNOON. NE-N WIND WILL GUST OVER 30 KT AT KCMX AND POSSIBLY AOA 25 KTS AT KSAW BY AFTERNOON. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 344 PM EDT TUE SEP 9 2014 THE TROUGH STRETCHED ACROSS W LAKE SUPERIOR WILL DRIFT ACROSS LAKE SUPERIOR THIS EVENING AS LOW PRESSURE APPROACHES FROM THE CENTRAL PLAINS. THE LOW WILL BE OVER E IOWA BY DAYBREAK WEDNESDAY...AND CONTINUE TO PUSH TO NRN LOWER MI BY WED EVENING...BEFORE EXITING INTO QUEBEC ON THURSDAY. NORTHEAST GALES TO AROUND 40KTS WILL BE POSSIBLE WEDNESDAY MORNING OVER W LAKE SUPERIOR...BEFORE SLOWLY EXPANDING TO CENTRAL LAKE SUPERIOR WEDNESDAY EVENING THROUGH THE OVERNIGHT HOURS AS WINDS BACK TO THE NORTH. LARGE HIGH PRESSURE OVER S ALBERTA AND SASKATCHEWAN THURSDAY WILL SINK ACROSS THE N AND CENTRAL PLAINS...WHILE BUILDING A RIDGE ACROSS LAKE SUPERIOR THURSDAY NIGHT THROUGH SATURDAY WITH WINDS GUSTING TO AROUND 20KTS OR LESS. && .HYDROLOGY... ISSUED AT 344 PM EDT TUE SEP 9 2014 RAINFALL TOTALS FROM TONIGHT THROUGH WEDNESDAY NIGHT ACROSS UPPER MI RANGE FROM JUST OVER 1.5 TO LOCALLY 3 INCHES. UNCERTAINTY REMAINS WHERE THE HEAVIER BANDS OF RAIN WILL DEVELOP. HIGHER TOTALS INTO WED NIGHT ARE EXPECTED FOR LOCATIONS IN N CNTRL UPPER MI WHERE STRONG UPSLOPE FLOW WILL BOOST RAINFALL AMOUNTS. THE FLOOD WATCH REMAINS POSTED FOR MUCH OF W AND CENTRAL UPPER MI. EXPECT THE TRADITIONAL URBAN/SMALL STREAM FLOODING TO BE A SIGNIFICANT POSSIBILITY IN THE TYPICAL POOR DRAINAGE AREAS OF ESC IF A PERIOD OF HEAVIER DOWNPOURS DEVELOP WITH RAINFALL RATES CLOSE TO AN 0.5-1.0 INCH PER HOUR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... FLOOD WATCH FROM 2 AM EDT /1 AM CDT/ WEDNESDAY THROUGH WEDNESDAY EVENING FOR MIZ001>006-009>013-084. LAKE SUPERIOR... GALE WARNING FROM 8 PM WEDNESDAY TO 8 AM EDT THURSDAY FOR LSZ251- 267. GALE WARNING FROM 2 PM WEDNESDAY TO 5 AM EDT THURSDAY FOR LSZ246>250-265-266. GALE WARNING FROM 8 AM WEDNESDAY TO 4 AM EDT THURSDAY FOR LSZ243>245-264. GALE WARNING FROM 5 AM EDT /4 AM CDT/ WEDNESDAY TO 2 AM EDT /1 AM CDT/ THURSDAY FOR LSZ240>242-263. GALE WARNING FROM 5 AM EDT /4 AM CDT/ TO 11 PM EDT /10 PM CDT/ WEDNESDAY FOR LSZ162. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...TITUS AVIATION...VOSS MARINE...JLB HYDROLOGY...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
434 PM EDT MON SEP 8 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 402 PM EDT MON SEP 8 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS AND SRN CANADA. A SHORTWAVE TROUGH OVER WI AND ASSOCIATED 700-300 MB QVECTOR CONV SUPPORTED SOME VERY LIGHT RAIN SHOWERS OR SPINKLES OVER NRN WI INTO FAR WRN UPPER MI. WITH THE FORCING MAINLY IN THE 500-300 MB LAYER AND RELATIVELY DRY LOW LEVELS JUST MID LEVEL CLOUDS/CIGS WERE REPORTED WITH MOST STATIONS NOT EVEN REPORTING ANY MEASURABLE AMOUNTS. OTHERWISE...PARLTY CLOUDY SKIES WITH GUSTY SOUTH WINDS OF 15 TO 25 MPH PREVAILED OVER THE REST OF THE CWA. TONIGHT...EXPECT THE -SHRA/SPRINKLES OVER SW UPPER MI TO SLOWLY SLIDE TO THE EAST THIS EVENING AS THE SHRTWV DEPARTS. THE LEFTOVER MID CLOUDS SHOULD ALSO THIN OUT OVERNIGHT AS QVECTOR DIV SPREADS INTO THE AREA. HOWEVER...WITH INCREASING SW FLOW 925-700 MB THETA-E ADVECTION ADDITIONAL CLOUDS MAY SPREAD INTO THE WEST HALF LATE. THE SRLY FLOW WILL KEEP MIN READINGS IN THE MID 50S INLAND TO AROUND 60 IN DOWNSLOPE LOCATIONS NEAR LAKE SUPERIOR. TUESDAY...THE MODELS SUGGEST THAT A FRONTAL BOUNDARY WILL SLOWLY DROP THROUGH WRN LAKE SUPERIOR AND AIDED BY THE LAKE BREEZE INTO THE NW CWA BY AFTERNOON. THE COMBINATION OF THE APPROACHING FRONTAL BOUNDARY...MLCAPE VALUES INTO THE 1K-2K RANGE...RELATIVELY WEAK CAPPING AND THE POTENTIAL A WEAK SHORTWAVE BRUSHING THE AREA MAY PRODUCE SOME ISOLD/SCT SHRA/TSRA BY MID TO LATE AFTERNOON OVER THE WEST HALF. SINCE THE STRONGEST FORCING IS EXPECTED TO REMAIN NW OF THE CWA...ONLY LOWER END CHANCE POPS WERE INCLUDED. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 431 PM EDT MON SEP 8 2014 THE MAIN ISSUES THIS FORECAST PERIOD WILL BE THE FLOODING POTENTIAL TUESDAY NIGHT THROUGH WEDNESDAY MORNING...GALES ON LAKE SUPERIOR WEDNESDAY INTO WEDNESDAY NIGHT AND COLDER THAN NORMAL TEMPERATURES MOVING IN THURSDAY NIGHT THROUGH SATURDAY. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...LOW PRESSURE WILL INTENSIFY OVER THE CENTRAL PLAINS AS IT LIFTS NORTHEASTWARD TO WESTERN IOWA LATE TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING AT OR AROUND 1000MB. AT THE SAME TIME...AN UPPER LEVEL 500MB TROUGH AXIS SLIDES ACROSS THE ROCKIES INTO THE PLAINS STATES. MODELS ARE IN FAIRLY GOOD AGREEMENT...HOWEVER...THE 12Z NAM IS A BIT OF AN OUTLIER...TAKING THE LOW FARTHER NORTH AND WEST THAN THE OTHER MODELS. SHOWERS AND THUNDERSTORMS WILL DEVELOP AHEAD OF THE LOW PRESSURE SYSTEM ON INCREASED MOISTURE UPGLIDE AS SHOWN ON THE 300K ISOSURFACE ALONG WITH INCREASING MOISTURE SHOWN BY PLOTTING 1000-500 RH. THE BEST CHANCE OF CONVECTION WOULD BE TUESDAY EVENING WITH INSTABILITY LINGERING ON THE WARM SIDE OF THE LOW. THE LOW WILL CONTINUE NORTHEASTWARD TO JUST SOUTH OF JAMES BAY WHILE FURTHER STRENGTHENING TO AROUND 990MB AS THE UPPER LEVEL TROUGH SLIDES INTO THE UPPER MISSISSIPPI VALLEY. AT THIS POINT...THE HEAVY RAINFALL POTENTIAL WOULD BE GREATEST LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING...AS DEEP LAYER MOISTURE WOULD BE IN PLACE AT THE SAME TIME ISENTROPIC UPGLIDE IS MAXIMIZED AND DEEP LAYER FORCING IS MAXIMIZED AS A FAIRLY STRONG 700MB FGEN BAND WRAPS THROUGH THE AREA. ADDITIONALLY...THE AREA WILL LIE IN THE LEFT EXIT REGION OF A JET MAX TO THE SOUTH AND PARTIALLY IN THE INFLUENCE OF A RIGHT ENTRANCE REGION OF A JET MAX TO THE NORTH. ALSO IN SUPPORT OF HEAVY RAINFALL TUESDAY NIGHT THROUGH WEDNESDAY MORNING WILL BE PWAT VALUES CONTINUING TO BE PROGGED AT 1.5 TO 2 INCHES ON STRONG SOUTHERLY MOISTURE TRANSPORT INTO THE REGION. RAINFALL WILL CONTINUE THROUGH WEDNESDAY NIGHT...HOWEVER...OVERALL INTENSITY IS EXPECTED TO DECREASE AS THE AFOREMENTIONED HEAVY RAINFALL FEATURES SHIFT OUT OF THE AREA AND MAINLY WRAP AROUND PRECIP LINGERS OVER GENERALLY THE WESTERN U.P. AS A DRY SLOT IS PROGGED TO WEDGE INTO THE CENTRAL AND EASTERN AREAS...ALLOWING FOR MAINLY DRIZZLE. HEAVY RAINFALL POTENTIAL INCLUDING AREAL FLOOD WATCH...WITH THE DEEP MOISTURE AND LIFT EXPECTED ACROSS THE AREA...RAINFALL TOTALS WILL LIKELY EXCEED 2 INCHES WITH UP TO 3 INCHES POSSIBLE ACROSS PORTIONS OF THE CENTRAL AND WESTERN UPPER PENINSULA. MOST OF THE RAINFALL IS EXPECTED TO OCCUR IN A 12 HOUR PERIOD...BETWEEN 06Z/10 AND 18Z/10. THIS HEAVY RAINFALL WILL OCCUR ON VERY SATURATED SOILS WHICH WILL ALLOW RUNOFF TO BEGIN QUICKLY. MANY AREAS OF THE CENTRAL AND WESTERN PORTIONS OF THE U.P. ARE RUNNING AROUND 2 TO 4 INCHES ABOVE THE 2 WEEK NORMAL DUE TO RECENT HEAVY RAINFALL. SEVERAL RIVERS WITHIN THE FLOOD WATCH ARE RUNNING HIGHER THAN NORMAL WITH ANY ADDITIONAL WIDESPREAD RAINFALL EXPECTED TO INCREASE THESE LEVEL...SOME OF WHICH MAY APPROACH FLOOD STAGE...BASED ON HEAVIER RAINFALL GUIDANCE. OUTSIDE OF THE RAINFALL POTENTIAL...STRONG WINDS WILL ALSO BE AN ISSUE. AS THE LOW PUSHES INTO THE REGION...A FAIRLY STRONG AREA OF HIGH PRESSURE WILL BUILD ACROSS MUCH OF WESTERN CANADA. THE PRESSURE GRADIENT WILL TIGHTEN BETWEEN THE TWO SYSTEMS LATE TUESDAY NIGHT AND ESPECIALLY DURING THE DAY WEDNESDAY. THE PERIOD OF STRONGEST WINDS ARE EXPECTED TO PUSH THROUGH THE AREA LATE WEDNESDAY MORNING THROUGH LATE WEDNESDAY NIGHT. WINDS OVER MUCH OF THE LAND AREAS AWAY FROM THE SHORE WILL BE SUSTAINED AROUND 15 TO 25 MPH. OVER THE LAKE...THE KEWEENAW PENINSULA AND AREAS NEAR THE SHORE WILL SEE WINDS SUSTAINED CLOSER TO 35 TO 40 MPH WITH GUSTS REACHING AROUND 45 TO EVEN 50 MPH. THIS IS SUPPORTED WITH CAA ACROSS THE LAKE ON THE BACK SIDE OF THE LOW WITH RELATIVELY WARM LAKE SURFACE TEMPERATURES ALLOWING STRONGER WINDS TO MIX DOWN TO THE LAKE SURFACE. SOUNDINGS SUPPORT WINDS MIXING DOWN FROM AROUND 925-900MB...WHERE WINDS ARE PROGGED TO BE RIGHT AROUND 45 TO 50 MPH. CONFIDENCE IN HIGH WINDS IS FAIRLY HIGH OVER THE LAKE...WITH A BIT LOWER CONFIDENCE IN THE WIND DIRECTION. HAVE DECIDED TO GO WITH A GALE WATCH BEGINNING WEDNESDAY MORNING INTO LATE WEDNESDAY NIGHT. THURSDAY THROUGH FRIDAY NIGHT...THE LOW PRESSURE SYSTEM NEAR JAMES BAY WILL CONTINUE TO SLOWLY LIFT NORTHEAST...PUSHING INTO QUEBEC BY THURSDAY AFTERNOON. AT THE SAME TIME...STRONG HIGH PRESSURE WILL BUILD ACROSS MUCH OF THE UPPER MISSISSIPPI VALLEY. THE PRESSURE GRADIENT MAY LINGER THROUGH THURSDAY MORNING OVER EASTERN LAKE SUPERIOR KEEPING GALE FORCE GUSTS IN THE FORECAST...HOWEVER...AS THE LOW SLIPS AWAY AND THE HIGH BUILDS IN...WINDS WILL DIMINISH DURING THE AFTERNOON HOURS THURSDAY. UPPER LEVEL TROUGHING WILL LINGER THROUGH FRIDAY NIGHT ACROSS THE AREA WITH A COUPLE SHORTWAVES PUSHING THROUGH. THE COOLER AIR ALOFT ASSOCIATED WITH THE TROUGH WILL ALLOW FOR CONTINUED CLOUD COVER ALONG WITH LIGHT RAIN SHOWERS. BY LATE FRIDAY NIGHT THE HIGH PRESSURE CENTER MOVES OVERHEAD ALONG WITH SLIGHT RIDGING ALOFT AND DRIER AIR...ALLOWING THE PRECIP TO END AND SKIES TO CLEAR. TEMPERATURES COULD BE QUITE COOL FRIDAY NIGHT WITH CALM CONDITIONS...CLEARING SKIES AND PWAT VALUES AROUND 30 TO 40 PERCENT OF NORMAL. KEPT THE IDEA OF SEEING BELOW FREEZING TEMPERATURES ACROSS INLAND AREAS OF THE U.P. SATURDAY THROUGH MONDAY...HIGH PRESSURE IS EXPECTED TO LINGER THROUGH SATURDAY...KEEPING CONDITIONS DRY AND SKIES MAINLY CLEAR. TEMPERATURES WILL BEGIN TO MODERATE SUNDAY INTO MONDAY ON RETURN SOUTHERLY FLOW ON THE WEST SIDE OF THE HIGH. THE GFS/EC HAVE ANOTHER SYSTEM PUSHING INTO THE AREA DURING THE SUNDAY NIGHT INTO MONDAY TIME PERIOD...HOWEVER...THERE IS QUITE A BIT OF UNCERTAINTY IN THE TRACK OF THE SYSTEM AND THE OVERALL STRENGTH AND TIMING OF THE UPPER LEVEL TROUGH. LEANED HEAVILY ON A CONSENSUS OF THE MODELS DURING THIS TIME PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 130 PM EDT MON SEP 8 2014 EXPECT VFR CONDITIONS THROUGH MOST OF THIS FCST PERIOD WITH STRONG SSW FLOW TAPPING RELATIVELY DRY AIR SHOWN ON THE 00Z MPX RAOB. DAYTIME HEATING/MIXING WILL ALLOW FOR GUSTY WINDS TO 20-25 KT THIS AFTERNOON BEFORE DECOUPLING THIS EVENING MIGHT ALLOW FOR SOME MARGINAL LLWS BEFORE THE LLJ WEAKENS AFTER 06Z. LOW LEVEL MOISTURE WILL INCREASE FROM THE SW TUE MORNING WITH MVFR CIGS LIKELY AT IWD AND CMX AND POSSIBLY AT SAW. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 402 PM EDT MON SEP 8 2014 SRLY WINDS TO 20 KNOTS WILL CONTINUE TONIGHT BETWEEN HIGH PRES OVER NEW ENGLAND AND A TROUGH FROM NW ONTARIO INTO THE NRN PLAINS. LOOK FOR THE TROUGH TO PUSH INTO LAKE SUPERIOR ON TUESDAY...WHILE A STRONGER LOW ORGANIZES ACROSS THE CENTRAL PLAINS. EXPECT THE DEEPENING LOW TO SHIFT NE ACROSS WI ON WEDNESDAY...AND ACROSS E UPPER MI AND N LOWER MI LATE WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING...BEFORE CONTINUING NE INTO QUEBEC ON THURSDAY. A PERIOD OF N GALES IS EXPECTED FROM WED MORNING THROUGH WED NIGHT. WINDS WILL DIMINISH THU AS HIGH PRES BUILDS FROM THE PLAINS INTO THE WRN LAKES. && .HYDROLOGY... ISSUED AT 431 PM EDT MON SEP 8 2014 HEAVY RAINFALL POTENTIAL INCLUDING AREAL FLOOD WATCH...WITH THE DEEP MOISTURE AND LIFT EXPECTED ACROSS THE AREA...RAINFALL TOTALS WILL LIKELY EXCEED 2 INCHES WITH UP TO 3 INCHES POSSIBLE ACROSS PORTIONS OF THE CENTRAL AND WESTERN UPPER PENINSULA. MOST OF THE RAINFALL IS EXPECTED TO OCCUR IN A 12 HOUR PERIOD...BETWEEN 06Z/10 AND 18Z/10. THIS HEAVY RAINFALL WILL OCCUR ON VERY SATURATED SOILS WHICH WILL ALLOW RUNOFF TO BEGIN QUICKLY. MANY AREAS OF THE CENTRAL AND WESTERN PORTIONS OF THE U.P. ARE RUNNING AROUND 2 TO 4 INCHES ABOVE THE 2 WEEK NORMAL DUE TO RECENT HEAVY RAINFALL. SEVERAL RIVERS WITHIN THE FLOOD WATCH ARE RUNNING SLIGHTLY HIGHER THAN NORMAL WITH ANY ADDITIONAL WIDESPREAD RAINFALL EXPECTED TO INCREASE THESE LEVEL...SOME OF WHICH MAY APPROACH FLOOD STAGE...BASED ON HEAVIER RAINFALL GUIDANCE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... FLOOD WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY EVENING FOR MIZ001>006-009>013-084. LAKE SUPERIOR... GALE WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR LSZ243>245-264>267. GALE WATCH FROM WEDNESDAY MORNING THROUGH LATE WEDNESDAY NIGHT FOR LSZ162-240>242-263. GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR LSZ248>251. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KEC AVIATION...JLB MARINE...JLB HYDROLOGY...KEC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
404 PM EDT MON SEP 8 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 402 PM EDT MON SEP 8 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS AND SRN CANADA. A SHORTWAVE TROUGH OVER WI AND ASSOCIATED 700-300 MB QVECTOR CONV SUPPORTED SOME VERY LIGHT RAIN SHOWERS OR SPINKLES OVER NRN WI INTO FAR WRN UPPER MI. WITH THE FORCING MAINLY IN THE 500-300 MB LAYER AND RELATIVELY DRY LOW LEVELS JUST MID LEVEL CLOUDS/CIGS WERE REPORTED WITH MOST STATIONS NOT EVEN REPORTING ANY MEASURABLE AMOUNTS. OTHERWISE...PARLTY CLOUDY SKIES WITH GUSTY SOUTH WINDS OF 15 TO 25 MPH PREVAILED OVER THE REST OF THE CWA. TONIGHT...EXPECT THE -SHRA/SPRINKLES OVER SW UPPER MI TO SLOWLY SLIDE TO THE EAST THIS EVENING AS THE SHRTWV DEPARTS. THE LEFTOVER MID CLOUDS SHOULD ALSO THIN OUT OVERNIGHT AS QVECTOR DIV SPREADS INTO THE AREA. HOWEVER...WITH INCREASING SW FLOW 925-700 MB THETA-E ADVECTION ADDITIONAL CLOUDS MAY SPREAD INTO THE WEST HALF LATE. THE SRLY FLOW WILL KEEP MIN READINGS IN THE MID 50S INLAND TO AROUND 60 IN DOWNSLOPE LOCATIONS NEAR LAKE SUPERIOR. TUESDAY...THE MODELS SUGGEST THAT A FRONTAL BOUNDARY WILL SLOWLY DROP THROUGH WRN LAKE SUPERIOR AND AIDED BY THE LAKE BREEZE INTO THE NW CWA BY AFTERNOON. THE COMBINATION OF THE APPROACHING FRONTAL BOUNDARY...MLCAPE VALUES INTO THE 1K-2K RANGE...RELATIVELY WEAK CAPPING AND THE POTENTIAL A WEAK SHORTWAVE BRUSHING THE AREA MAY PRODUCE SOME ISOLD/SCT SHRA/TSRA BY MID TO LATE AFTERNOON OVER THE WEST HALF. SINCE THE STRONGEST FORCING IS EXPECTED TO REMAIN NW OF THE CWA...ONLY LOWER END CHANCE POPS WERE INCLUDED. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 441 AM EDT MON SEP 8 2014 THE MAIN THREATS THIS PERIOD WILL BE THE HEAVY RAIN TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...STRONG NORTHERLY WINDS LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT ALONG LAKE SUPERIOR...AND A PROLONGED PERIOD OF COOL WEATHER STARTING THURSDAY WITH NEAR OR BELOW FREEZING TEMPERATURES ANTICIPATED LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING /COOLEST INLAND FROM THE GREAT LAKES/. TUESDAY... THE LAST DAY OF ABOVE NORMAL TEMPERATURES...OR EVEN NEAR NORMAL TEMPERATURES FOR THE NEXT WEEK WILL BE TUESDAY. FAVORABLE S WINDS OVER THE E HALF OF UPPER MI SHOULD ALLOW AREAS NEAR LAKE SUPERIOR TO RISE INTO THE MID TO UPPER 70S...WITH LOW 70S COMMON ELSEWHERE. LOOK FOR A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS OVER THE W HALF OF THE CWA AS THE SFC TROUGH CONNECTING LOWS OVER CENTRAL PLAINS AND HUDSON BAY SHIFTS ACROSS THE CWA. BROAD W TO SW FLOW ALOFT WILL KEEP SWINGING DISTURBANCES ACROSS THE AREA AT 500MB. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT... MODELS ARE COMING INTO BETTER AGREEMENT FOR THE TRACK OF THE SFC LOW EJECTING NE OUT OF THE CENTRAL PLAINS TUESDAY NIGHT. LOOK FOR THE SFC LOW TO BE SET UP ACROSS S MN AND IA AT 06Z TO SHIFT OVER S CENTRAL UPPER MI/NE WI/N LAKE MI BY MID AFTERNOON. THIS WILL BRING WIDESPREAD RAIN TO THE REGION. WITH PW VALUES RISING TO 1.5-2IN HEAVY RAIN IS A CONCERN. CURRENTLY HAVE 1.5 TO JUST OVER 2IN OF RAIN FCST FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. KEPT THE SMALL CHANCE OF THUNDERSTORMS ALONG LAKE MI WEDNESDAY. WITH THE TRACK OF THE SFC LOW...AND STRONG HIGH PRESSURE SET UP OVER CENTRAL AND S ALBERTA/SASKATCHEWAN...STRONG N WINDS OF 40-45MPH WILL BE POSSIBLE LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...WITH THE STRONGEST WINDS MOSTLY LIKELY ACROSS THE KEWEENAW PENINSULA. A WIND ADVISORY MAY BE NEEDED FOR THE KEWEENAW PENINSULA. AS PREVIOUSLY NOTED...EVEN IF WINDS DON/T QUITE REACH ADVISORY CRITERIA...TREES COULD BE MORE SUSCEPTIBLE TO FALLING DUE TO THE SATURATED GROUND AND PLENTY OF LEAVES ON THE TREES. WEDNESDAY NIGHT THROUGH SUNDAY... THE SFC LOW WILL SHIFT OVER ONTARIO AND QUEBEC WEDNESDAY NIGHT...WITH THE SFC TROUGH LINGERING ACROSS UPPER MI INTO THURSDAY. NW FLOW WILL BRING IN PLENTY OF COLD AIR BEHIND THE LOW...WITH TEMPERATURES REMAINING WELL BELOW NORMAL THROUGH AT LEAST THE UPCOMING WEEKEND. 850MB TEMPS OF -1C BY 18Z THURSDAY WILL RESULT IN LAKE EFFECT RAIN WHICH WILL LINGER THROUGH FRIDAY AS A SECOND WAVE AND TROUGH AXIS MORE ACROSS THE CWA THURSDAY NIGHT-FRIDAY. HAVE ADDED THE POTENTIAL FOR NEAR OR BELOW FREEZING TEMPS INLAND FROM THE GREAT LAKES...AND PRIMARILY OVER THE W HALF OF UPPER MI LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING AS THE LARGE AREA OF HIGH PRESSURE TO THE W BUILDS OVERHEAD WITH DECREASING CLOUDS. WINDS WILL BECOME MORE W OR OUT OF THE S ON SATURDAY...EFFECTIVELY ENDING OUR LAKE EFFECT CLOUDS OR SHOWERS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 130 PM EDT MON SEP 8 2014 EXPECT VFR CONDITIONS THROUGH MOST OF THIS FCST PERIOD WITH STRONG SSW FLOW TAPPING RELATIVELY DRY AIR SHOWN ON THE 00Z MPX RAOB. DAYTIME HEATING/MIXING WILL ALLOW FOR GUSTY WINDS TO 20-25 KT THIS AFTERNOON BEFORE DECOUPLING THIS EVENING MIGHT ALLOW FOR SOME MARGINAL LLWS BEFORE THE LLJ WEAKENS AFTER 06Z. LOW LEVEL MOISTURE WILL INCREASE FROM THE SW TUE MORNING WITH MVFR CIGS LIKELY AT IWD AND CMX AND POSSIBLY AT SAW. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 402 PM EDT MON SEP 8 2014 SRLY WINDS TO 20 KNOTS WILL CONTINUE TONIGHT BETWEEN HIGH PRES OVER NEW ENGLAND AND A TROUGH FROM NW ONTARIO INTO THE NRN PLAINS. LOOK FOR THE TROUGH TO PUSH INTO LAKE SUPERIOR ON TUESDAY...WHILE A STRONGER LOW ORGANIZES ACROSS THE CENTRAL PLAINS. EXPECT THE DEEPENING LOW TO SHIFT NE ACROSS WI ON WEDNESDAY...AND ACROSS E UPPER MI AND N LOWER MI LATE WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING...BEFORE CONTINUING NE INTO QUEBEC ON THURSDAY. A PERIOD OF N GALES IS EXPECTED FROM WED MORNING THROUGH WED NIGHT. WINDS WILL DIMINISH THU AS HIGH PRES BUILDS FROM THE PLAINS INTO THE WRN LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... FLOOD WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY EVENING FOR MIZ001>006-009>013-084. LAKE SUPERIOR... GALE WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR LSZ243>245-264>267. GALE WATCH FROM WEDNESDAY MORNING THROUGH LATE WEDNESDAY NIGHT FOR LSZ162-240>242-263. GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR LSZ248>251. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
131 PM EDT MON SEP 8 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 332 AM EDT MON SEP 8 2014 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT ZONAL FLOW ALF ALONG THE CNDN BORDER. A SHRTWV RDG EMBEDDED IN THIS W-E FLOW IS MOVING THRU THE UPR LKS EARLY THIS MRNG...SUPPORTING SFC HI PRES OVER THE SE GREAT LKS. ACYC SW FLOW ARND THIS HI AND DRY AIRMASS SHOWN ON LOCAL 00Z RAOBS...ESPECIALLY AT MPX WHERE THE 00Z PWAT IS 0.48 INCH OR 60 PCT OF NORMAL...ARE RESULTING IN MOCLR CONDITIONS ACRS UPR MI. BUT HI CLDS ARE APRCHG WRN UPR MI IN ADVANCE OF A SHRTWV MOVING E THRU THE NRN PLAINS IN THE SRN BRANCH FLOW. ANOTHER SHRTWV WITHIN THE STRONGER NRN BRANCH IS PUSHING EWD THRU SRN SASKATCHEWAN. MAIN FCST CONCERNS IN THE SHORT TERM WL BE WHETHER AND IF THEN HOW QUICKLY SHOWERS SPREAD INTO UPR MI IN ADVANCE OF UPSTREAM SHRTWVS. TODAY...SRN BRANCH DISTURBANCE IN THE NRN PLAINS EARLY THIS MRNG IS PROGGED TO MOVE E AND INTO NRN WI BY 00Z TUE. ALTHOUGH UPR MI WL BE ON THE FAVORED CYC SIDE OF THE TRACK OF THIS DISTURBANCE... PERSISTENT SW FLOW ARND SFC HI PRES MOVING INTO NEW ENGLAND WL ADVECT DRIER AIR FM THE SW AND THE DIRECTION OF MPX. SO ALTHOUGH PVA/H5-3 QVECTOR CNVGC AHEAD OF THE SHRTWV IS FCST TO IMPACT MAINLY THE S HALF OF UPR MI...MODELS INDICATE AN ABSENCE OF ANY SGNFT H85-5 QVECTOR CNVGC. THIS SETUP SUGGESTS THE MAIN IMPACT WL BE THE HI CLDS SPILLING E FM MN. SO EVEN THOUGH SOME MODELS GENERATE PCPN NEAR THE WI BORDER AFTER 18Z...OPTED TO MAINTAIN GOING DRY FCST. FCST H85 TEMPS RANGING FM ABOUT 11C OVER THE E TO 13C OVER THE W AND MIXING TO H8-85 AS OBSVD UPSTREAM YDAY SUPPORTS HI TEMPS IN THE MID/UPR 70S. SSW FLOW OFF LK MI WL BRING COOLER WX TO THE ERN CWA. THE DAYTIME HEATING/MIXING AND H925 WINDS IN THE 20-30KT RANGE WL RESULT IN GUSTY WINDS BY LATE MRNG. GIVEN THE FVRBL CONDITIONS FOR GUSTY WINDS...BUMPED UP FCST GUSTS A COUPLE OF KTS ABV WIND GUST PROCEDURE OUTPUT. TNGT...UPR MI IS FCST TO BE DOMINATED BY DEEP LYR QVECTOR DVGC BTWN DEPARTING SRN BRANCH SHRTWV THRU NRN LOWER MI AND NRN BRANCH DISTURBANCE CROSSING NW ONTARIO. SO ALTHOUGH THE PERSISTENT SW FLOW BTWN THE HI PRES MOVING INTO THE CNDN MARITIMES AND AN APRCHG COLD FNT ATTENDANT TO THE NRN BRANCH SHRTWV WL BRING A RETURN OF HIER H85 THETA E INTO THE UPR LKS...LINGERING MID LVL DRY AIR BEST SHOWN BY THE 00Z GFS FCST SDNGS WARRANTS KEEPING THE GOING DRY FCST. STEADY SW WIND AND INCRSG LLVL MSTR THAT MAY RESULT IN SOME SC ESPECIALLY OVER THE W HALF CLOSER TO THE HIER H85 THETA E WL RESULT IN WELL ABV NORMAL MIN TEMPS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 441 AM EDT MON SEP 8 2014 THE MAIN THREATS THIS PERIOD WILL BE THE HEAVY RAIN TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...STRONG NORTHERLY WINDS LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT ALONG LAKE SUPERIOR...AND A PROLONGED PERIOD OF COOL WEATHER STARTING THURSDAY WITH NEAR OR BELOW FREEZING TEMPERATURES ANTICIPATED LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING /COOLEST INLAND FROM THE GREAT LAKES/. TUESDAY... THE LAST DAY OF ABOVE NORMAL TEMPERATURES...OR EVEN NEAR NORMAL TEMPERATURES FOR THE NEXT WEEK WILL BE TUESDAY. FAVORABLE S WINDS OVER THE E HALF OF UPPER MI SHOULD ALLOW AREAS NEAR LAKE SUPERIOR TO RISE INTO THE MID TO UPPER 70S...WITH LOW 70S COMMON ELSEWHERE. LOOK FOR A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS OVER THE W HALF OF THE CWA AS THE SFC TROUGH CONNECTING LOWS OVER CENTRAL PLAINS AND HUDSON BAY SHIFTS ACROSS THE CWA. BROAD W TO SW FLOW ALOFT WILL KEEP SWINGING DISTURBANCES ACROSS THE AREA AT 500MB. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT... MODELS ARE COMING INTO BETTER AGREEMENT FOR THE TRACK OF THE SFC LOW EJECTING NE OUT OF THE CENTRAL PLAINS TUESDAY NIGHT. LOOK FOR THE SFC LOW TO BE SET UP ACROSS S MN AND IA AT 06Z TO SHIFT OVER S CENTRAL UPPER MI/NE WI/N LAKE MI BY MID AFTERNOON. THIS WILL BRING WIDESPREAD RAIN TO THE REGION. WITH PW VALUES RISING TO 1.5-2IN HEAVY RAIN IS A CONCERN. CURRENTLY HAVE 1.5 TO JUST OVER 2IN OF RAIN FCST FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. KEPT THE SMALL CHANCE OF THUNDERSTORMS ALONG LAKE MI WEDNESDAY. WITH THE TRACK OF THE SFC LOW...AND STRONG HIGH PRESSURE SET UP OVER CENTRAL AND S ALBERTA/SASKATCHEWAN...STRONG N WINDS OF 40-45MPH WILL BE POSSIBLE LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...WITH THE STRONGEST WINDS MOSTLY LIKELY ACROSS THE KEWEENAW PENINSULA. A WIND ADVISORY MAY BE NEEDED FOR THE KEWEENAW PENINSULA. AS PREVIOUSLY NOTED...EVEN IF WINDS DON/T QUITE REACH ADVISORY CRITERIA...TREES COULD BE MORE SUSCEPTIBLE TO FALLING DUE TO THE SATURATED GROUND AND PLENTY OF LEAVES ON THE TREES. WEDNESDAY NIGHT THROUGH SUNDAY... THE SFC LOW WILL SHIFT OVER ONTARIO AND QUEBEC WEDNESDAY NIGHT...WITH THE SFC TROUGH LINGERING ACROSS UPPER MI INTO THURSDAY. NW FLOW WILL BRING IN PLENTY OF COLD AIR BEHIND THE LOW...WITH TEMPERATURES REMAINING WELL BELOW NORMAL THROUGH AT LEAST THE UPCOMING WEEKEND. 850MB TEMPS OF -1C BY 18Z THURSDAY WILL RESULT IN LAKE EFFECT RAIN WHICH WILL LINGER THROUGH FRIDAY AS A SECOND WAVE AND TROUGH AXIS MORE ACROSS THE CWA THURSDAY NIGHT-FRIDAY. HAVE ADDED THE POTENTIAL FOR NEAR OR BELOW FREEZING TEMPS INLAND FROM THE GREAT LAKES...AND PRIMARILY OVER THE W HALF OF UPPER MI LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING AS THE LARGE AREA OF HIGH PRESSURE TO THE W BUILDS OVERHEAD WITH DECREASING CLOUDS. WINDS WILL BECOME MORE W OR OUT OF THE S ON SATURDAY...EFFECTIVELY ENDING OUR LAKE EFFECT CLOUDS OR SHOWERS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 130 PM EDT MON SEP 8 2014 EXPECT VFR CONDITIONS THROUGH MOST OF THIS FCST PERIOD WITH STRONG SSW FLOW TAPPING RELATIVELY DRY AIR SHOWN ON THE 00Z MPX RAOB. DAYTIME HEATING/MIXING WILL ALLOW FOR GUSTY WINDS TO 20-25 KT THIS AFTERNOON BEFORE DECOUPLING THIS EVENING MIGHT ALLOW FOR SOME MARGINAL LLWS BEFORE THE LLJ WEAKENS AFTER 06Z. LOW LEVEL MOISTURE WILL INCREASE FROM THE SW TUE MORNING WITH MVFR CIGS LIKELY AT IWD AND CMX AND POSSIBLY AT SAW. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 332 AM EDT MON SEP 8 2014 FOG MAY CONTINUE TO BE A CONCERN INITIALLY OVER PORTIONS OF W AND CENTRAL LAKE SUPERIOR. LAKE SUPERIOR WILL INITIALLY BE STUCK BETWEEN EXITING HIGH PRESSURE OVER THE NEW ENGLAND STATES...AND A NEARING TROUGH STRETCHING FROM NORTH DAKOTA THROUGH NORTHERN ONTARIO. LOOK FOR THE TROUGH TO PUSH INTO LAKE SUPERIOR ON TUESDAY...WHILE A STRONGER LOW ORGANIZES ACROSS THE CENTRAL PLAINS. EXPECT THE DEEPENING LOW TO SHIFT NE ACROSS WI ON WEDNESDAY...AND ACROSS E UPPER MI AND N LOWER MI LATE WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING...BEFORE CONTINUING NE INTO QUEBEC ON THURSDAY. A PERIOD OF N GALES WILL BE POSSIBLE LATE TUESDAY NIGHT INTO EARLY THURSDAY. IN LARGE HIGH PRESSURE OVER S ALBERTA AND SASKATCHEWAN THURSDAY IS EXPECTED TO DIVE ACROSS THE N AND CENTRAL PLAINS...WHILE BUILDING A RIDGE ACROSS LAKE SUPERIOR ON THURSDAY NIGHT AND FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...JLB MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
730 AM EDT MON SEP 8 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 332 AM EDT MON SEP 8 2014 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT ZONAL FLOW ALF ALONG THE CNDN BORDER. A SHRTWV RDG EMBEDDED IN THIS W-E FLOW IS MOVING THRU THE UPR LKS EARLY THIS MRNG...SUPPORTING SFC HI PRES OVER THE SE GREAT LKS. ACYC SW FLOW ARND THIS HI AND DRY AIRMASS SHOWN ON LOCAL 00Z RAOBS...ESPECIALLY AT MPX WHERE THE 00Z PWAT IS 0.48 INCH OR 60 PCT OF NORMAL...ARE RESULTING IN MOCLR CONDITIONS ACRS UPR MI. BUT HI CLDS ARE APRCHG WRN UPR MI IN ADVANCE OF A SHRTWV MOVING E THRU THE NRN PLAINS IN THE SRN BRANCH FLOW. ANOTHER SHRTWV WITHIN THE STRONGER NRN BRANCH IS PUSHING EWD THRU SRN SASKATCHEWAN. MAIN FCST CONCERNS IN THE SHORT TERM WL BE WHETHER AND IF THEN HOW QUICKLY SHOWERS SPREAD INTO UPR MI IN ADVANCE OF UPSTREAM SHRTWVS. TODAY...SRN BRANCH DISTURBANCE IN THE NRN PLAINS EARLY THIS MRNG IS PROGGED TO MOVE E AND INTO NRN WI BY 00Z TUE. ALTHOUGH UPR MI WL BE ON THE FAVORED CYC SIDE OF THE TRACK OF THIS DISTURBANCE... PERSISTENT SW FLOW ARND SFC HI PRES MOVING INTO NEW ENGLAND WL ADVECT DRIER AIR FM THE SW AND THE DIRECTION OF MPX. SO ALTHOUGH PVA/H5-3 QVECTOR CNVGC AHEAD OF THE SHRTWV IS FCST TO IMPACT MAINLY THE S HALF OF UPR MI...MODELS INDICATE AN ABSENCE OF ANY SGNFT H85-5 QVECTOR CNVGC. THIS SETUP SUGGESTS THE MAIN IMPACT WL BE THE HI CLDS SPILLING E FM MN. SO EVEN THOUGH SOME MODELS GENERATE PCPN NEAR THE WI BORDER AFTER 18Z...OPTED TO MAINTAIN GOING DRY FCST. FCST H85 TEMPS RANGING FM ABOUT 11C OVER THE E TO 13C OVER THE W AND MIXING TO H8-85 AS OBSVD UPSTREAM YDAY SUPPORTS HI TEMPS IN THE MID/UPR 70S. SSW FLOW OFF LK MI WL BRING COOLER WX TO THE ERN CWA. THE DAYTIME HEATING/MIXING AND H925 WINDS IN THE 20-30KT RANGE WL RESULT IN GUSTY WINDS BY LATE MRNG. GIVEN THE FVRBL CONDITIONS FOR GUSTY WINDS...BUMPED UP FCST GUSTS A COUPLE OF KTS ABV WIND GUST PROCEDURE OUTPUT. TNGT...UPR MI IS FCST TO BE DOMINATED BY DEEP LYR QVECTOR DVGC BTWN DEPARTING SRN BRANCH SHRTWV THRU NRN LOWER MI AND NRN BRANCH DISTURBANCE CROSSING NW ONTARIO. SO ALTHOUGH THE PERSISTENT SW FLOW BTWN THE HI PRES MOVING INTO THE CNDN MARITIMES AND AN APRCHG COLD FNT ATTENDANT TO THE NRN BRANCH SHRTWV WL BRING A RETURN OF HIER H85 THETA E INTO THE UPR LKS...LINGERING MID LVL DRY AIR BEST SHOWN BY THE 00Z GFS FCST SDNGS WARRANTS KEEPING THE GOING DRY FCST. STEADY SW WIND AND INCRSG LLVL MSTR THAT MAY RESULT IN SOME SC ESPECIALLY OVER THE W HALF CLOSER TO THE HIER H85 THETA E WL RESULT IN WELL ABV NORMAL MIN TEMPS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 441 AM EDT MON SEP 8 2014 THE MAIN THREATS THIS PERIOD WILL BE THE HEAVY RAIN TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...STRONG NORTHERLY WINDS LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT ALONG LAKE SUPERIOR...AND A PROLONGED PERIOD OF COOL WEATHER STARTING THURSDAY WITH NEAR OR BELOW FREEZING TEMPERATURES ANTICIPATED LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING /COOLEST INLAND FROM THE GREAT LAKES/. TUESDAY... THE LAST DAY OF ABOVE NORMAL TEMPERATURES...OR EVEN NEAR NORMAL TEMPERATURES FOR THE NEXT WEEK WILL BE TUESDAY. FAVORABLE S WINDS OVER THE E HALF OF UPPER MI SHOULD ALLOW AREAS NEAR LAKE SUPERIOR TO RISE INTO THE MID TO UPPER 70S...WITH LOW 70S COMMON ELSEWHERE. LOOK FOR A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS OVER THE W HALF OF THE CWA AS THE SFC TROUGH CONNECTING LOWS OVER CENTRAL PLAINS AND HUDSON BAY SHIFTS ACROSS THE CWA. BROAD W TO SW FLOW ALOFT WILL KEEP SWINGING DISTURBANCES ACROSS THE AREA AT 500MB. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT... MODELS ARE COMING INTO BETTER AGREEMENT FOR THE TRACK OF THE SFC LOW EJECTING NE OUT OF THE CENTRAL PLAINS TUESDAY NIGHT. LOOK FOR THE SFC LOW TO BE SET UP ACROSS S MN AND IA AT 06Z TO SHIFT OVER S CENTRAL UPPER MI/NE WI/N LAKE MI BY MID AFTERNOON. THIS WILL BRING WIDESPREAD RAIN TO THE REGION. WITH PW VALUES RISING TO 1.5-2IN HEAVY RAIN IS A CONCERN. CURRENTLY HAVE 1.5 TO JUST OVER 2IN OF RAIN FCST FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. KEPT THE SMALL CHANCE OF THUNDERSTORMS ALONG LAKE MI WEDNESDAY. WITH THE TRACK OF THE SFC LOW...AND STRONG HIGH PRESSURE SET UP OVER CENTRAL AND S ALBERTA/SASKATCHEWAN...STRONG N WINDS OF 40-45MPH WILL BE POSSIBLE LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...WITH THE STRONGEST WINDS MOSTLY LIKELY ACROSS THE KEWEENAW PENINSULA. A WIND ADVISORY MAY BE NEEDED FOR THE KEWEENAW PENINSULA. AS PREVIOUSLY NOTED...EVEN IF WINDS DON/T QUITE REACH ADVISORY CRITERIA...TREES COULD BE MORE SUSCEPTIBLE TO FALLING DUE TO THE SATURATED GROUND AND PLENTY OF LEAVES ON THE TREES. WEDNESDAY NIGHT THROUGH SUNDAY... THE SFC LOW WILL SHIFT OVER ONTARIO AND QUEBEC WEDNESDAY NIGHT...WITH THE SFC TROUGH LINGERING ACROSS UPPER MI INTO THURSDAY. NW FLOW WILL BRING IN PLENTY OF COLD AIR BEHIND THE LOW...WITH TEMPERATURES REMAINING WELL BELOW NORMAL THROUGH AT LEAST THE UPCOMING WEEKEND. 850MB TEMPS OF -1C BY 18Z THURSDAY WILL RESULT IN LAKE EFFECT RAIN WHICH WILL LINGER THROUGH FRIDAY AS A SECOND WAVE AND TROUGH AXIS MORE ACROSS THE CWA THURSDAY NIGHT-FRIDAY. HAVE ADDED THE POTENTIAL FOR NEAR OR BELOW FREEZING TEMPS INLAND FROM THE GREAT LAKES...AND PRIMARILY OVER THE W HALF OF UPPER MI LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING AS THE LARGE AREA OF HIGH PRESSURE TO THE W BUILDS OVERHEAD WITH DECREASING CLOUDS. WINDS WILL BECOME MORE W OR OUT OF THE S ON SATURDAY...EFFECTIVELY ENDING OUR LAKE EFFECT CLOUDS OR SHOWERS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 729 AM EDT MON SEP 8 2014 EXPECT VFR CONDITIONS THIS FCST PERIOD WITH STRONG SSW FLOW TAPPING RELATIVELY DRY AIR SHOWN ON THE 00Z MPX RAOB. DAYTIME HEATING/MIXING WL ALLOW FOR GUSTY WINDS TO 20-25 KT THIS AFTN BEFORE DECOUPLING THIS EVNG CAUSES SOME MARGINAL LLWS BEFORE THE LLJ WEAKENS AFTER 06Z. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 332 AM EDT MON SEP 8 2014 FOG MAY CONTINUE TO BE A CONCERN INITIALLY OVER PORTIONS OF W AND CENTRAL LAKE SUPERIOR. LAKE SUPERIOR WILL INITIALLY BE STUCK BETWEEN EXITING HIGH PRESSURE OVER THE NEW ENGLAND STATES...AND A NEARING TROUGH STRETCHING FROM NORTH DAKOTA THROUGH NORTHERN ONTARIO. LOOK FOR THE TROUGH TO PUSH INTO LAKE SUPERIOR ON TUESDAY...WHILE A STRONGER LOW ORGANIZES ACROSS THE CENTRAL PLAINS. EXPECT THE DEEPENING LOW TO SHIFT NE ACROSS WI ON WEDNESDAY...AND ACROSS E UPPER MI AND N LOWER MI LATE WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING...BEFORE CONTINUING NE INTO QUEBEC ON THURSDAY. A PERIOD OF N GALES WILL BE POSSIBLE LATE TUESDAY NIGHT INTO EARLY THURSDAY. IN LARGE HIGH PRESSURE OVER S ALBERTA AND SASKATCHEWAN THURSDAY IS EXPECTED TO DIVE ACROSS THE N AND CENTRAL PLAINS...WHILE BUILDING A RIDGE ACROSS LAKE SUPERIOR ON THURSDAY NIGHT AND FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...KC MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
443 AM EDT MON SEP 8 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 332 AM EDT MON SEP 8 2014 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT ZONAL FLOW ALF ALONG THE CNDN BORDER. A SHRTWV RDG EMBEDDED IN THIS W-E FLOW IS MOVING THRU THE UPR LKS EARLY THIS MRNG...SUPPORTING SFC HI PRES OVER THE SE GREAT LKS. ACYC SW FLOW ARND THIS HI AND DRY AIRMASS SHOWN ON LOCAL 00Z RAOBS...ESPECIALLY AT MPX WHERE THE 00Z PWAT IS 0.48 INCH OR 60 PCT OF NORMAL...ARE RESULTING IN MOCLR CONDITIONS ACRS UPR MI. BUT HI CLDS ARE APRCHG WRN UPR MI IN ADVANCE OF A SHRTWV MOVING E THRU THE NRN PLAINS IN THE SRN BRANCH FLOW. ANOTHER SHRTWV WITHIN THE STRONGER NRN BRANCH IS PUSHING EWD THRU SRN SASKATCHEWAN. MAIN FCST CONCERNS IN THE SHORT TERM WL BE WHETHER AND IF THEN HOW QUICKLY SHOWERS SPREAD INTO UPR MI IN ADVANCE OF UPSTREAM SHRTWVS. TODAY...SRN BRANCH DISTURBANCE IN THE NRN PLAINS EARLY THIS MRNG IS PROGGED TO MOVE E AND INTO NRN WI BY 00Z TUE. ALTHOUGH UPR MI WL BE ON THE FAVORED CYC SIDE OF THE TRACK OF THIS DISTURBANCE... PERSISTENT SW FLOW ARND SFC HI PRES MOVING INTO NEW ENGLAND WL ADVECT DRIER AIR FM THE SW AND THE DIRECTION OF MPX. SO ALTHOUGH PVA/H5-3 QVECTOR CNVGC AHEAD OF THE SHRTWV IS FCST TO IMPACT MAINLY THE S HALF OF UPR MI...MODELS INDICATE AN ABSENCE OF ANY SGNFT H85-5 QVECTOR CNVGC. THIS SETUP SUGGESTS THE MAIN IMPACT WL BE THE HI CLDS SPILLING E FM MN. SO EVEN THOUGH SOME MODELS GENERATE PCPN NEAR THE WI BORDER AFTER 18Z...OPTED TO MAINTAIN GOING DRY FCST. FCST H85 TEMPS RANGING FM ABOUT 11C OVER THE E TO 13C OVER THE W AND MIXING TO H8-85 AS OBSVD UPSTREAM YDAY SUPPORTS HI TEMPS IN THE MID/UPR 70S. SSW FLOW OFF LK MI WL BRING COOLER WX TO THE ERN CWA. THE DAYTIME HEATING/MIXING AND H925 WINDS IN THE 20-30KT RANGE WL RESULT IN GUSTY WINDS BY LATE MRNG. GIVEN THE FVRBL CONDITIONS FOR GUSTY WINDS...BUMPED UP FCST GUSTS A COUPLE OF KTS ABV WIND GUST PROCEDURE OUTPUT. TNGT...UPR MI IS FCST TO BE DOMINATED BY DEEP LYR QVECTOR DVGC BTWN DEPARTING SRN BRANCH SHRTWV THRU NRN LOWER MI AND NRN BRANCH DISTURBANCE CROSSING NW ONTARIO. SO ALTHOUGH THE PERSISTENT SW FLOW BTWN THE HI PRES MOVING INTO THE CNDN MARITIMES AND AN APRCHG COLD FNT ATTENDANT TO THE NRN BRANCH SHRTWV WL BRING A RETURN OF HIER H85 THETA E INTO THE UPR LKS...LINGERING MID LVL DRY AIR BEST SHOWN BY THE 00Z GFS FCST SDNGS WARRANTS KEEPING THE GOING DRY FCST. STEADY SW WIND AND INCRSG LLVL MSTR THAT MAY RESULT IN SOME SC ESPECIALLY OVER THE W HALF CLOSER TO THE HIER H85 THETA E WL RESULT IN WELL ABV NORMAL MIN TEMPS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 441 AM EDT MON SEP 8 2014 THE MAIN THREATS THIS PERIOD WILL BE THE HEAVY RAIN TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...STRONG NORTHERLY WINDS LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT ALONG LAKE SUPERIOR...AND A PROLONGED PERIOD OF COOL WEATHER STARTING THURSDAY WITH NEAR OR BELOW FREEZING TEMPERATURES ANTICIPATED LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING /COOLEST INLAND FROM THE GREAT LAKES/. TUESDAY... THE LAST DAY OF ABOVE NORMAL TEMPERATURES...OR EVEN NEAR NORMAL TEMPERATURES FOR THE NEXT WEEK WILL BE TUESDAY. FAVORABLE S WINDS OVER THE E HALF OF UPPER MI SHOULD ALLOW AREAS NEAR LAKE SUPERIOR TO RISE INTO THE MID TO UPPER 70S...WITH LOW 70S COMMON ELSEWHERE. LOOK FOR A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS OVER THE W HALF OF THE CWA AS THE SFC TROUGH CONNECTING LOWS OVER CENTRAL PLAINS AND HUDSON BAY SHIFTS ACROSS THE CWA. BROAD W TO SW FLOW ALOFT WILL KEEP SWINGING DISTURBANCES ACROSS THE AREA AT 500MB. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT... MODELS ARE COMING INTO BETTER AGREEMENT FOR THE TRACK OF THE SFC LOW EJECTING NE OUT OF THE CENTRAL PLAINS TUESDAY NIGHT. LOOK FOR THE SFC LOW TO BE SET UP ACROSS S MN AND IA AT 06Z TO SHIFT OVER S CENTRAL UPPER MI/NE WI/N LAKE MI BY MID AFTERNOON. THIS WILL BRING WIDESPREAD RAIN TO THE REGION. WITH PW VALUES RISING TO 1.5-2IN HEAVY RAIN IS A CONCERN. CURRENTLY HAVE 1.5 TO JUST OVER 2IN OF RAIN FCST FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. KEPT THE SMALL CHANCE OF THUNDERSTORMS ALONG LAKE MI WEDNESDAY. WITH THE TRACK OF THE SFC LOW...AND STRONG HIGH PRESSURE SET UP OVER CENTRAL AND S ALBERTA/SASKATCHEWAN...STRONG N WINDS OF 40-45MPH WILL BE POSSIBLE LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...WITH THE STRONGEST WINDS MOSTLY LIKELY ACROSS THE KEWEENAW PENINSULA. A WIND ADVISORY MAY BE NEEDED FOR THE KEWEENAW PENINSULA. AS PREVIOUSLY NOTED...EVEN IF WINDS DON/T QUITE REACH ADVISORY CRITERIA...TREES COULD BE MORE SUSCEPTIBLE TO FALLING DUE TO THE SATURATED GROUND AND PLENTY OF LEAVES ON THE TREES. WEDNESDAY NIGHT THROUGH SUNDAY... THE SFC LOW WILL SHIFT OVER ONTARIO AND QUEBEC WEDNESDAY NIGHT...WITH THE SFC TROUGH LINGERING ACROSS UPPER MI INTO THURSDAY. NW FLOW WILL BRING IN PLENTY OF COLD AIR BEHIND THE LOW...WITH TEMPERATURES REMAINING WELL BELOW NORMAL THROUGH AT LEAST THE UPCOMING WEEKEND. 850MB TEMPS OF -1C BY 18Z THURSDAY WILL RESULT IN LAKE EFFECT RAIN WHICH WILL LINGER THROUGH FRIDAY AS A SECOND WAVE AND TROUGH AXIS MORE ACROSS THE CWA THURSDAY NIGHT-FRIDAY. HAVE ADDED THE POTENTIAL FOR NEAR OR BELOW FREEZING TEMPS INLAND FROM THE GREAT LAKES...AND PRIMARILY OVER THE W HALF OF UPPER MI LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING AS THE LARGE AREA OF HIGH PRESSURE TO THE W BUILDS OVERHEAD WITH DECREASING CLOUDS. WINDS WILL BECOME MORE W OR OUT OF THE S ON SATURDAY...EFFECTIVELY ENDING OUR LAKE EFFECT CLOUDS OR SHOWERS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 123 AM EDT MON SEP 8 2014 EXPECT VFR CONDITIONS THIS FCST PERIOD. DAYTIME HEATING/MIXING WL ALLOW FOR GUSTY WINDS TO 15-20 KT MON AFTN AND WINDS WILL STAY UP THROUGH MON EVENING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 332 AM EDT MON SEP 8 2014 FOG MAY CONTINUE TO BE A CONCERN INITIALLY OVER PORTIONS OF W AND CENTRAL LAKE SUPERIOR. LAKE SUPERIOR WILL INITIALLY BE STUCK BETWEEN EXITING HIGH PRESSURE OVER THE NEW ENGLAND STATES...AND A NEARING TROUGH STRETCHING FROM NORTH DAKOTA THROUGH NORTHERN ONTARIO. LOOK FOR THE TROUGH TO PUSH INTO LAKE SUPERIOR ON TUESDAY...WHILE A STRONGER LOW ORGANIZES ACROSS THE CENTRAL PLAINS. EXPECT THE DEEPENING LOW TO SHIFT NE ACROSS WI ON WEDNESDAY...AND ACROSS E UPPER MI AND N LOWER MI LATE WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING...BEFORE CONTINUING NE INTO QUEBEC ON THURSDAY. A PERIOD OF N GALES WILL BE POSSIBLE LATE TUESDAY NIGHT INTO EARLY THURSDAY. IN LARGE HIGH PRESSURE OVER S ALBERTA AND SASKATCHEWAN THURSDAY IS EXPECTED TO DIVE ACROSS THE N AND CENTRAL PLAINS...WHILE BUILDING A RIDGE ACROSS LAKE SUPERIOR ON THURSDAY NIGHT AND FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...07 MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
333 AM EDT MON SEP 8 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 332 AM EDT MON SEP 8 2014 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT ZONAL FLOW ALF ALONG THE CNDN BORDER. A SHRTWV RDG EMBEDDED IN THIS W-E FLOW IS MOVING THRU THE UPR LKS EARLY THIS MRNG...SUPPORTING SFC HI PRES OVER THE SE GREAT LKS. ACYC SW FLOW ARND THIS HI AND DRY AIRMASS SHOWN ON LOCAL 00Z RAOBS...ESPECIALLY AT MPX WHERE THE 00Z PWAT IS 0.48 INCH OR 60 PCT OF NORMAL...ARE RESULTING IN MOCLR CONDITIONS ACRS UPR MI. BUT HI CLDS ARE APRCHG WRN UPR MI IN ADVANCE OF A SHRTWV MOVING E THRU THE NRN PLAINS IN THE SRN BRANCH FLOW. ANOTHER SHRTWV WITHIN THE STRONGER NRN BRANCH IS PUSHING EWD THRU SRN SASKATCHEWAN. MAIN FCST CONCERNS IN THE SHORT TERM WL BE WHETHER AND IF THEN HOW QUICKLY SHOWERS SPREAD INTO UPR MI IN ADVANCE OF UPSTREAM SHRTWVS. TODAY...SRN BRANCH DISTURBANCE IN THE NRN PLAINS EARLY THIS MRNG IS PROGGED TO MOVE E AND INTO NRN WI BY 00Z TUE. ALTHOUGH UPR MI WL BE ON THE FAVORED CYC SIDE OF THE TRACK OF THIS DISTURBANCE... PERSISTENT SW FLOW ARND SFC HI PRES MOVING INTO NEW ENGLAND WL ADVECT DRIER AIR FM THE SW AND THE DIRECTION OF MPX. SO ALTHOUGH PVA/H5-3 QVECTOR CNVGC AHEAD OF THE SHRTWV IS FCST TO IMPACT MAINLY THE S HALF OF UPR MI...MODELS INDICATE AN ABSENCE OF ANY SGNFT H85-5 QVECTOR CNVGC. THIS SETUP SUGGESTS THE MAIN IMPACT WL BE THE HI CLDS SPILLING E FM MN. SO EVEN THOUGH SOME MODELS GENERATE PCPN NEAR THE WI BORDER AFTER 18Z...OPTED TO MAINTAIN GOING DRY FCST. FCST H85 TEMPS RANGING FM ABOUT 11C OVER THE E TO 13C OVER THE W AND MIXING TO H8-85 AS OBSVD UPSTREAM YDAY SUPPORTS HI TEMPS IN THE MID/UPR 70S. SSW FLOW OFF LK MI WL BRING COOLER WX TO THE ERN CWA. THE DAYTIME HEATING/MIXING AND H925 WINDS IN THE 20-30KT RANGE WL RESULT IN GUSTY WINDS BY LATE MRNG. GIVEN THE FVRBL CONDITIONS FOR GUSTY WINDS...BUMPED UP FCST GUSTS A COUPLE OF KTS ABV WIND GUST PROCEDURE OUTPUT. TNGT...UPR MI IS FCST TO BE DOMINATED BY DEEP LYR QVECTOR DVGC BTWN DEPARTING SRN BRANCH SHRTWV THRU NRN LOWER MI AND NRN BRANCH DISTURBANCE CROSSING NW ONTARIO. SO ALTHOUGH THE PERSISTENT SW FLOW BTWN THE HI PRES MOVING INTO THE CNDN MARITIMES AND AN APRCHG COLD FNT ATTENDANT TO THE NRN BRANCH SHRTWV WL BRING A RETURN OF HIER H85 THETA E INTO THE UPR LKS...LINGERING MID LVL DRY AIR BEST SHOWN BY THE 00Z GFS FCST SDNGS WARRANTS KEEPING THE GOING DRY FCST. STEADY SW WIND AND INCRSG LLVL MSTR THAT MAY RESULT IN SOME SC ESPECIALLY OVER THE W HALF CLOSER TO THE HIER H85 THETA E WL RESULT IN WELL ABV NORMAL MIN TEMPS. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 330 PM EDT SUN SEP 7 2014 MONDAY NIGHT INTO TUESDAY WILL BE THE TRANSITION PERIOD FROM THE DRY AND RELATIVELY WARM HIGH PRESSURE DEPARTING THE AREA TO THE MUCH COOLER AND WET PERIOD IN STORE FOR THE SECOND HALF OF THE WORK WEEK. THE START OF THIS TRANSITION WILL BE A COLD FRONT EXTENDING SOUTHWEST FROM A LOW NEAR HUDSON BAY. THIS FRONT WILL SLOWLY SHIFT TO THE EAST OUT OF MINNESOTA ON MONDAY NIGHT AND INTO WESTERN LAKE SUPERIOR AND THE WESTERN U.P. TUESDAY. EXPECT ISOLATED/SCATTERED SHOWERS TO OCCUR ALONG THIS FRONT AS IT SLOWLY MOVES EAST ACROSS THE U.P. LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT. DID CONTINUE TO INCLUDE A SLIGHT CHANCE OF THUNDER ON THE EAST SIDE OF THE FRONT/TROUGH DUE TO THE INSTABILITY INCREASING UNDER THE SOUTHERLY FLOW DURING THE AFTERNOON BEFORE DIMINISHING IN THE EVENING. THIS SLOW MOVING TROUGH WILL BE THE FOCUS FOR THE TRACK OF THE STRONG LOW PRESSURE SYSTEM THAT WILL BE DEVELOPING IN THE CENTRAL PLAINS ON TUESDAY AND THEN QUICKLY LIFTING NORTHEAST THROUGH THE UPPER GREAT LAKES REGION WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT. STILL SOME DIFFERENCES IN THE LOW TRACK BETWEEN THE OPERATIONAL MEMBERS AND ITS LOCATION AT 00Z THURSDAY...BUT THE 00Z ECMWF OR 12Z GEM RUNS SEEM TO BE A GOOD COMPROMISE WITH THE OTHER MODELS AND ENSEMBLE MEMBERS. THIS CONSENSUS TRACKS A LOW-MID 990MB LOW FROM SOUTHEAST MINNESOTA AT 12Z WEDNESDAY TO NORTHERN LAKE MICHIGAN BY 00Z THURSDAY AND INTO QUEBEC ON THURSDAY. 06Z GFS AND 00Z ECMWF ENSEMBLE MEMBERS SUPPORT THAT IDEA AND AWAY FROM THE FASTER AND FARTHER EAST SOLUTION SEEN ON THE 12Z GFS. WITH THAT IDEA IN MIND...EXPECT A TRANSITION FROM THE LIGHTER PRECIP ASSOCIATED WITH THE SURFACE TROUGH OVER WESTERN/CENTRAL U.P. ON TUESDAY NIGHT TO WIDESPREAD RAIN LIFTING NORTHEAST ACROSS THE AREA ON WEDNESDAY. WILL CONTINUE TO SHOW INCREASING POPS DURING THAT PERIOD AS THE ISENTROPIC ASCENT PUSHES THROUGH THE AREA AND DECIDED UP THE WEDNESDAY POPS TO DEFINITE VALUES ACROSS THE CWA. DID ADD A SMALL POCKET OF THUNDER ALONG THE LAKE MICHIGAN BORDER WEDNESDAY WHERE THE SURFACE LOW WILL TRACK AND POCKET OF ELEVATED INSTABILITY WOULD BE LOCATED. AS THE LOW LIFTS NORTHEAST ON WEDNESDAY NIGHT...EXPECT THE RAIN TO LINGER THE LONGEST OVER THE WEST AND ESPECIALLY THE KEWEENAW PENINSULA WHICH WILL BE JUST TO THE WEST/NORTHWEST OF THE 850/700MB LOW TRACK. WITH THE INITIAL SURGE OF PRECIPITATION ASSOCIATED WITH THIS LOW...HAVE RAINFALL AMOUNTS OVER AN 1.25 INCH ACROSS THE ENTIRE AREA THROUGH WEDNESDAY NIGHT AND THE HIGHEST AMOUNTS OVER NORTHWEST UPPER MICHIGAN (AMOUNTS OF 1.5-2IN). IN ADDITION TO THE RAIN...WINDS WILL BE ON THE INCREASE FROM WEST TO EAST WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT WITH SOLID NORTHERLY GALES OVER LAKE SUPERIOR. EXPECT THE STRONG WINDS TO AFFECT THE SHORELINE AREAS WEDNESDAY NIGHT (GUSTS TO 35KTS) BEFORE GRADUALLY DECREASING THURSDAY THROUGH FRIDAY. HAVE WINDS RIGHT AROUND WIND ADVISORY CRITERIA OVER NORTHERN PORTIONS OF THE KEWEENAW PENINSULA AND EVEN IF THEY DON/T REACH CRITERIA...THERE COULD BE DECENT IMPACTS WITH A SATURATED GROUND AND LEAVES ON THE TREES HELPING TO CAUSE SOME TREES TO FALL DOWN. THE NORTHWEST FLOW BEHIND THE LOW WILL USHER IN COLD AIR ALOFT (850 TEMPS OF -1C BY 18Z THURSDAY) AND LEAD TO LAKE EFFECT RAIN UNDER NORTHWEST FLOW UNTIL THE SECOND WAVE AND TROUGH AXIS MOVES THROUGH THURSDAY NIGHT INTO FRIDAY. THIS WILL BRING ANOTHER AREA OF WIDESPREAD LIGHT RAIN SHOWERS TO THE AREA. BEHIND THAT SECOND WAVE...EXPECT DRYING CONDITIONS AS AN UPPER/SURFACE RIDGE MOVE INTO THE AREA THROUGH SUNDAY MORNING. DEPENDING ON HOW QUICKLY SKIES CLEAR ON FRIDAY NIGHT...COULD SEE LOWS NEARING FREEZING. THINK BEST CHANCE WOULD BE OVER THE INTERIOR WEST AS IS TRADITIONALLY THE CASE WITH BACKING LOW LEVEL WINDS. THURSDAY THROUGH SATURDAY WILL BE A COOL STRETCH AND EXPECT HIGHS TO BE IN THE 50S EACH DAY. OVER THE WEST ON THURSDAY/FRIDAY...COULD SEE SOME LOCATIONS STRUGGLING TO RISE OUT OF THE UPPER 40S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 123 AM EDT MON SEP 8 2014 EXPECT VFR CONDITIONS THIS FCST PERIOD. DAYTIME HEATING/MIXING WL ALLOW FOR GUSTY WINDS TO 15-20 KT MON AFTN AND WINDS WILL STAY UP THROUGH MON EVENING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 332 AM EDT MON SEP 8 2014 FOG MAY CONTINUE TO BE A CONCERN INITIALLY OVER PORTIONS OF W AND CENTRAL LAKE SUPERIOR. LAKE SUPERIOR WILL INITIALLY BE STUCK BETWEEN EXITING HIGH PRESSURE OVER THE NEW ENGLAND STATES...AND A NEARING TROUGH STRETCHING FROM NORTH DAKOTA THROUGH NORTHERN ONTARIO. LOOK FOR THE TROUGH TO PUSH INTO LAKE SUPERIOR ON TUESDAY...WHILE A STRONGER LOW ORGANIZES ACROSS THE CENTRAL PLAINS. EXPECT THE DEEPENING LOW TO SHIFT NE ACROSS WI ON WEDNESDAY...AND ACROSS E UPPER MI AND N LOWER MI LATE WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING...BEFORE CONTINUING NE INTO QUEBEC ON THURSDAY. A PERIOD OF N GALES WILL BE POSSIBLE LATE TUESDAY NIGHT INTO EARLY THURSDAY. IN LARGE HIGH PRESSURE OVER S ALBERTA AND SASKATCHEWAN THURSDAY IS EXPECTED TO DIVE ACROSS THE N AND CENTRAL PLAINS...WHILE BUILDING A RIDGE ACROSS LAKE SUPERIOR ON THURSDAY NIGHT AND FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...SRF AVIATION...07 MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
125 AM EDT MON SEP 8 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 358 PM EDT SUN SEP 7 2014 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER THE UPR LAKES BTWN A BROAD UPR RDG OVER WRN NAMERICA AND A TROF OVER THE NE STATES. SHRTWV EMBEDDED IN THIS WNW FLOW WHICH WAS RESPONSIBLE FOR CLOUD COVER AND ISOLD SHRA OVER ERN LAKE SUPERIOR HAS NOW MOVED EAST OF LAKE SUPERIOR WITH CLOUD COVER GENERALLY ERODING. ANOTHER SHORTWAVE MOVING EAST THROUGH SOUTH DAKOTA HAS GENERATED SOME WAA CLOUDS OVER ERN SD BUT NO PCPN AT THIS TIME AS AIR MASS VERY DRY AS NOTED ON 12Z ABR SNDG. MAIN FCST CONCERNS WILL FOCUS MAINLY ON TEMPS AND CLOUDS AS AIRMASS LOOKS TO BE TOO DRY FOR PCPN OVER THE NEXT 24 HRS. TNGT...TIGHTENING PRES GRADIENT BTWN HI PRES RETREATING TOWARD NEW ENGLAND AND LO PRES TAKING SHAPE SW OF LK WINNIPEG WILL ALLOW FOR AN INCREASE IN SSW WIND ACROSS THE AREA TONIGHT. ALTHOUGH THE AIRMASS WL BE DRY AND SKIES MOSTLY CLR WITH PWATS AROUND 0.75 INCH...THE STEADY WIND WL TEND TO LIMIT THE DIURNAL TEMP DROP...ESPECIALLY IN THE DOWNSLOPE AREAS NEAR LK SUP OVER NW UPR MI. EXPECT THE LOWEST MIN TEMPS (MID TO UPPER 40S) OVER THE INTERIOR ALONG THE WI BDR AND E WHERE THE PRES GRADIENT WL BE A BIT WEAKER/WINDS LIGHTER. CONVERSELY MIN TEMPS FOR DOWNSLOPING AREAS ALONG LAKE SUPERIOR WILL STAY UP IN THE MID TO UPPER 50S. WAA WILL CONTINUE ON MONDAY WITH INCREASING S WINDS AS UPPER MI REMAINS STUCK BETWEEN A LARGE AREA OF HIGH PRESSURE EXITING THE NEW ENGLAND STATES...AND AN ELONGATED LOW PRES TROUGH SET UP FROM THE CENTRAL PLAINS THROUGH ONTARIO AND HUDSON BAY. 850MB TEMPS WILL AVERAGE 11-12C BY THE END OF THE DAY SHOULD YIELD HIGH TEMPS IN THE MID TO UPPER 70S ACROSS THE AREA DESPITE SOME INCREASE IN WAA CLOUDS AHEAD OF APPROACHING PLAINS SHORTWAVE. SOUTH GUSTS NEAR 20KTS WILL BE COMMON IN THE AFTERNOON. GIVEN DRY AIRMASS IN PLACE HAVE ELECTED TO KEEP FCST DRY FOR NOW DESPITE SOME WEAK FORCING AHEAD OF PLAINS SHORTWAVE. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 330 PM EDT SUN SEP 7 2014 MONDAY NIGHT INTO TUESDAY WILL BE THE TRANSITION PERIOD FROM THE DRY AND RELATIVELY WARM HIGH PRESSURE DEPARTING THE AREA TO THE MUCH COOLER AND WET PERIOD IN STORE FOR THE SECOND HALF OF THE WORK WEEK. THE START OF THIS TRANSITION WILL BE A COLD FRONT EXTENDING SOUTHWEST FROM A LOW NEAR HUDSON BAY. THIS FRONT WILL SLOWLY SHIFT TO THE EAST OUT OF MINNESOTA ON MONDAY NIGHT AND INTO WESTERN LAKE SUPERIOR AND THE WESTERN U.P. TUESDAY. EXPECT ISOLATED/SCATTERED SHOWERS TO OCCUR ALONG THIS FRONT AS IT SLOWLY MOVES EAST ACROSS THE U.P. LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT. DID CONTINUE TO INCLUDE A SLIGHT CHANCE OF THUNDER ON THE EAST SIDE OF THE FRONT/TROUGH DUE TO THE INSTABILITY INCREASING UNDER THE SOUTHERLY FLOW DURING THE AFTERNOON BEFORE DIMINISHING IN THE EVENING. THIS SLOW MOVING TROUGH WILL BE THE FOCUS FOR THE TRACK OF THE STRONG LOW PRESSURE SYSTEM THAT WILL BE DEVELOPING IN THE CENTRAL PLAINS ON TUESDAY AND THEN QUICKLY LIFTING NORTHEAST THROUGH THE UPPER GREAT LAKES REGION WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT. STILL SOME DIFFERENCES IN THE LOW TRACK BETWEEN THE OPERATIONAL MEMBERS AND ITS LOCATION AT 00Z THURSDAY...BUT THE 00Z ECMWF OR 12Z GEM RUNS SEEM TO BE A GOOD COMPROMISE WITH THE OTHER MODELS AND ENSEMBLE MEMBERS. THIS CONSENSUS TRACKS A LOW-MID 990MB LOW FROM SOUTHEAST MINNESOTA AT 12Z WEDNESDAY TO NORTHERN LAKE MICHIGAN BY 00Z THURSDAY AND INTO QUEBEC ON THURSDAY. 06Z GFS AND 00Z ECMWF ENSEMBLE MEMBERS SUPPORT THAT IDEA AND AWAY FROM THE FASTER AND FARTHER EAST SOLUTION SEEN ON THE 12Z GFS. WITH THAT IDEA IN MIND...EXPECT A TRANSITION FROM THE LIGHTER PRECIP ASSOCIATED WITH THE SURFACE TROUGH OVER WESTERN/CENTRAL U.P. ON TUESDAY NIGHT TO WIDESPREAD RAIN LIFTING NORTHEAST ACROSS THE AREA ON WEDNESDAY. WILL CONTINUE TO SHOW INCREASING POPS DURING THAT PERIOD AS THE ISENTROPIC ASCENT PUSHES THROUGH THE AREA AND DECIDED UP THE WEDNESDAY POPS TO DEFINITE VALUES ACROSS THE CWA. DID ADD A SMALL POCKET OF THUNDER ALONG THE LAKE MICHIGAN BORDER WEDNESDAY WHERE THE SURFACE LOW WILL TRACK AND POCKET OF ELEVATED INSTABILITY WOULD BE LOCATED. AS THE LOW LIFTS NORTHEAST ON WEDNESDAY NIGHT...EXPECT THE RAIN TO LINGER THE LONGEST OVER THE WEST AND ESPECIALLY THE KEWEENAW PENINSULA WHICH WILL BE JUST TO THE WEST/NORTHWEST OF THE 850/700MB LOW TRACK. WITH THE INITIAL SURGE OF PRECIPITATION ASSOCIATED WITH THIS LOW...HAVE RAINFALL AMOUNTS OVER AN 1.25 INCH ACROSS THE ENTIRE AREA THROUGH WEDNESDAY NIGHT AND THE HIGHEST AMOUNTS OVER NORTHWEST UPPER MICHIGAN (AMOUNTS OF 1.5-2IN). IN ADDITION TO THE RAIN...WINDS WILL BE ON THE INCREASE FROM WEST TO EAST WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT WITH SOLID NORTHERLY GALES OVER LAKE SUPERIOR. EXPECT THE STRONG WINDS TO AFFECT THE SHORELINE AREAS WEDNESDAY NIGHT (GUSTS TO 35KTS) BEFORE GRADUALLY DECREASING THURSDAY THROUGH FRIDAY. HAVE WINDS RIGHT AROUND WIND ADVISORY CRITERIA OVER NORTHERN PORTIONS OF THE KEWEENAW PENINSULA AND EVEN IF THEY DON/T REACH CRITERIA...THERE COULD BE DECENT IMPACTS WITH A SATURATED GROUND AND LEAVES ON THE TREES HELPING TO CAUSE SOME TREES TO FALL DOWN. THE NORTHWEST FLOW BEHIND THE LOW WILL USHER IN COLD AIR ALOFT (850 TEMPS OF -1C BY 18Z THURSDAY) AND LEAD TO LAKE EFFECT RAIN UNDER NORTHWEST FLOW UNTIL THE SECOND WAVE AND TROUGH AXIS MOVES THROUGH THURSDAY NIGHT INTO FRIDAY. THIS WILL BRING ANOTHER AREA OF WIDESPREAD LIGHT RAIN SHOWERS TO THE AREA. BEHIND THAT SECOND WAVE...EXPECT DRYING CONDITIONS AS AN UPPER/SURFACE RIDGE MOVE INTO THE AREA THROUGH SUNDAY MORNING. DEPENDING ON HOW QUICKLY SKIES CLEAR ON FRIDAY NIGHT...COULD SEE LOWS NEARING FREEZING. THINK BEST CHANCE WOULD BE OVER THE INTERIOR WEST AS IS TRADITIONALLY THE CASE WITH BACKING LOW LEVEL WINDS. THURSDAY THROUGH SATURDAY WILL BE A COOL STRETCH AND EXPECT HIGHS TO BE IN THE 50S EACH DAY. OVER THE WEST ON THURSDAY/FRIDAY...COULD SEE SOME LOCATIONS STRUGGLING TO RISE OUT OF THE UPPER 40S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 123 AM EDT MON SEP 8 2014 EXPECT VFR CONDITIONS THIS FCST PERIOD. DAYTIME HEATING/MIXING WL ALLOW FOR GUSTY WINDS TO 15-20 KT MON AFTN AND WINDS WILL STAY UP THROUGH MON EVENING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 358 PM EDT SUN SEP 7 2014 LARGE HIGH PRESSURE STRETCHING FROM THE CENTRAL PLAINS THROUGH THE LOWER GREAT LAKES WILL EXIT TO THE NEW ENGLAND STATES TONIGHT. MEANWHILE...A LOW PRES TROUGH WILL DEVELOP FROM HUDSON BAY THROUGH WRN ONTARIO INTO THE NRN PLAINS. LOW PRES DEVELOPING OVER THE CENTRAL PLAINS BY TUE WILL MOVE NE ACROSS THE UPPER GREAT LAKES LATE WEDNESDAY AND WEDNESDAY NIGHT...BEFORE EXITING INTO QUEBEC ON THURSDAY. A PERIOD OF N GALES WILL BE POSSIBLE LATE TUE NIGHT INTO EARLY THURSDAY. INCLUDED AREAS OF FOG OVER NCNTRL LAKE SUPERIOR WHERE PATCH OF FOG HAS RESIDED MUCH OF THE AFTERNOON. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...SRF AVIATION...07 MARINE...VOSS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
343 PM CDT MON SEP 8 2014 .SHORT TERM...(TONIGHT THROUGH THURSDAY) ISSUED AT 333 PM CDT MON SEP 8 2014 MAIN FORECAST CHALLENGE FOR THE SHORT TERM IS SEVERE POTENTIAL TUESDAY/TUESDAY EVENING...WITH TEMPERATURES BECOMING THE MAIN ISSUE IN THE LONGER TERM. SCATTERED SHOWERS/THUNDERSTORMS CONTINUE ACROSS PORTIONS OF OUR NORTHEASTERN CWA AHEAD OF A VERY SUBTLE SHORTWAVE TROUGH MOVING THROUGH THE WESTERLIES. THIS ACTIVITY SHOULD CONTINUE TO SHIFT EAST WITH THE SHORTWAVE ENERGY THROUGH THE EVENING AND OVERNIGHT HOURS. MOSTLY SUNNY CONDITIONS ACROSS THE REMAINDER OF THE CWA HAVE ALLOWED A DIURNALLY DRIVEN CU FIELD TO DEVELOP. BOTH THE LATEST HRRR AND THE RAP INDICATE SOME CONVECTIVE ACTIVITY DEVELOPING OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA AFTER 00Z ALONG THE THETA-E AXIS AND HAVE INCLUDED SOME LOW POPS TO ACCOUNT FOR THIS THIS EVENING. MAIN WEATHER CONCERN COMES ALONG WITH THE SHORTWAVE TROUGH CURRENTLY ON THE NORTHERN CALIFORNIA COAST. THIS FEATURE WILL DEAMPLIFY AS IT SLIDES EAST TOWARD COLORADO OVER THE NEXT 24 HOURS. AHEAD OF THIS...A LEE CYCLONE WILL DEEPEN AND MOVE INTO SOUTHWESTERN KANSAS BY 00Z WED. A WARM FRONT WILL EXTEND E/NE ACROSS KANSAS AND SHOULD DRIFT INTO OUR SOUTHERN CWA BY MID AFTERNOON. ANY STORMS THAT DEVELOP WITH THE INCREASING SFC CONVERGENCE NEAR THE FRONT SHOULD QUICKLY GO SEVERE AND ROTATE WITH INCREASINGLY STRONG SHEAR PROFILES. AREA CONTINUES TO BE OUTLOOKED IN A SLIGHT RISK IN THE SWODY2. SOME UNCERTAINTY CONTINUES IN REGARDS TO ANY LATE MORNING/EARLY AFTERNOON CONVECTIVE CHANCES AHEAD OF A WEAK LEAD SHORTWAVE EJECTING OUT AHEAD OF THE MAIN TROUGH. WILL CONTINUE SOME SMALLER POPS FOR THIS...BUT MAIN SEVERE POTENTIAL WILL BE LATE AFTERNOON/EARLY EVENING. THUNDERSTORMS WILL CONTINUE TO BE WIDESPREAD AHEAD OF THE APPROACHING SFC LOW AS IT SLIDES NORTHEAST OVER THE CWA BY 06Z/WED. SOUTHWESTERLY 45-55KT LLVL JET THROUGH THE EVENING HOURS SHOULD SUSTAIN THUNDERSTORMS AFTER DARK WHEN HEAVY RAIN RATHER THAN SEVERE STORMS WILL BE A THREAT. PW`S THROUGH THE EVENING DO APPROACH 2.50" DURING THIS TIME. BY 12Z/WED THE SFC LOW WILL BE CENTERED ACROSS NORTHERN IOWA WITH SOME LINGERING ACTIVITY THROUGH WED MORNING BEHIND THE LOW. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 333 PM CDT MON SEP 8 2014 A DEEPENING UPPER TROUGH OVER WESTERN CANADA WILL DROP SOUTHEAST INTO THE CENTRAL PLAINS LATER THIS WEEK BRINGING MUCH COLDER AIR INTO THE REGION. IN FACT...WE MAY BE APPROACHING RECORD COLD HIGHS...ESPECIALLY THURSDAY WHEN WE HAVE HIGHS FORECAST IN THE MID TO UPPER 50S. COLD RAIN IS LOOKING MORE LIKELY ON THURSDAY NIGHT/FRIDAY MORNING AHEAD OF A SHARPENING UPPER TROUGH. IF TIMING REMAINS SIMILAR TO WHAT MODELS ARE INDICATING...THE RAIN SHOULD BE OUT OF THE AREA BY FRIDAY AFTERNOON. THE FORECAST FOR THE WEEKEND LOOKS DRY WITH SOME SLIGHT MODERATION IN TEMPERATURES. && .AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1217 PM CDT MON SEP 8 2014 GENERALLY VFR CONDITIONS ARE EXPECTED ACROSS EASTERN NEBRASKA TAF SITES THROUGH 18Z TUESDAY. SCATTERED SHOWERS IN NORTHEAST NEBRASKA COULD AFFECT KOFK FOR A FEW HOURS THIS AFTERNOON. THEN THERE IS A SMALL CHANCE THUNDERSTORMS COULD DEVELOP BY 00Z THIS EVENING...BUT MOST OF THAT ACTIVITY IS EXPECTED TO FIRE SOUTHEAST OF KOMA AND KLNK. AN INCREASE OF MID LEVEL CLOUDS IS EXPECTED LATE TONIGHT AND TUESDAY AHEAD OF A STORM SYSTEM MOVING INTO THE PLAINS. WIDESPREAD THUNDERSTORMS ARE FORECAST AFTER THE END OF THIS TAF CYCLE. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...KERN LONG TERM...KERN AVIATION...DERGAN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1227 PM CDT MON SEP 8 2014 .UPDATE... ISSUED AT 1217 PM CDT MON SEP 8 2014 PESKY SHOWERS CONTINUE ACROSS NORTHEAST NEBRASKA TIED TO A WEAK WAVE IN MID LEVEL FLOW. PLENTY OF SUNSHINE OUTSIDE OF THESE SHOWERS WAS ALLOWING INSTABILITY TO INCREASE ACROSS THE AREA EARLY THIS AFTERNOON. WHILE SOME CAPPING WAS STILL IN PLACE...CONTINUED EROSION COULD LEAD TO CONVECTIVE DEVELOPMENT IN PARTS OF EASTERN NEBRASKA AND WESTERN IOWA LATE TODAY OR THIS EVENING. OUTFLOW FROM EARLIER CONVECTION COULD PROVIDE A FOCUS FOR STORMS IN WEST CENTRAL IOWA LATER TODAY...EXPANDING INTO SOUTHEAST NEBRASKA THIS EVENING. WILL CONTINUE WITH OUR MENTION OF SLIGHT CHANCE FOR STORMS TODAY IN THOSE AREAS. ANOTHER POTENTIAL BOUNDARY OF CONCERN IS A WARM FRONT EXTENDING FROM NORTHEAST NEBRASKA TO NEAR NEBRASKA CITY...WITH GUSTY SOUTH WINDS ON THE WARM SIDE OF THIS BOUNDARY AND SOUTHEAST WINDS ON THE COOLER SIDE. WILL CONTINUE TO MONITOR THESE AREAS FOR INCREASED POTENTIAL FOR STORMS TODAY AND THIS EVENING. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 255 AM CDT MON SEP 8 2014 HOW FAR SOUTH INTO THE FA WILL MORNING CONVECTION MAKE IT AND THEN HOW QUICKLY WILL CONVECTION DEVELOP ON TUESDAY MAIN FORECAST FOCUS IN THE SHORT TERM...ALTHOUGH SEVERE WEATHER AND HEAVY RAIN REMAIN IN THE PICTURE FOR LATE TUESDAY. A MERGING THUNDERSTORM CLUSTER WAS WORKING TOWARD NERN NEBR AS OF 8Z BUT ALSO MOVING INTO MLCAPE VALUE AREAS THAT WERE LESS THAN 500 J/KG PER SPC MESO PAGE. THUS WOULD SUSPECT SOME WEAKENING ON SE EDGE THIS MORNING WHICH WAS HINTED AT BY 05Z HRRR AND RAP WHICH KEPT MOST OF THE PRECIP IN FAR NE ZONES OR EVEN NE OF THERE...AS DID 00Z ECMWF. HOWEVER...THAT SAID CONVECTION WAS MAINTAINING ITS STRENGTH ENOUGH TO DISCOUNT SHORT TERM MODELS TO SOME DEGREE AND TO INCREASE POPS IN NERN ZONES THIS MORNING AND KEEP MENTION OF THEM PER PREV FORECAST IN THE AFTN ALONG E OF MO RIVER. DON/T KNOW IF IT WILL HOLD TOGETHER AND ROLL DOWN MO RIVER TO OMAHA...BUT CAN/T RULE THAT OUT ATTM. ALSO SOME HINT BY NAM AND 4KM WRF THAT SOME NEW DEVELOPMENT COULD OCCUR ON SW SIDE THIS MORNING AND THUS LEFT IN SMALL POPS FARTHER SW THAN RAP/HRRR WOULD SUGGEST. STILL COUNTING ON DEBRIS BEING MINIMAL ENOUGH THIS AFTN TO ALLOW MAX TEMPS TO REACH 80 OR BETTER ALL BUT PERHAPS FAR NERN ZONES. ALTHOUGH SOME SMALL POPS WERE MAINTAINED TONIGHT...STILL APPEARED THAT MAIN CONVECTIVE AREAS WOULD EITHER BE TO OUR EAST ON NOSE OF H85 THETAE RIDGE/JET OR TO OUR WEST AS UPPER TROUGH AND MID LEVEL MOISTURE APPROACH. THIS MOISTURE...WITH H7 DWPTS FORECAST AT 8-10 DEG C PER NAM/GFS...COULD ALLOW CONVECTION TO START OR INCREASE FAIRLY EARLY TUESDAY AFTN AND LEAD TO LOCALLY HEAVY RAIN BY EVENING AS PWATS WILL BE HIGH AND TRAINING OF CELLS PROBABLE. HOWEVER...A LOT COULD/WILL DEPEND ON INITIAL DEVELOPMENT AND RESULTANT OUTFLOW OR DIFFERENTIAL HEATING AREAS AND WILL REFRAIN FROM BLANKET HEAVY RAIN MENTION JUST YET. WITH GENERAL MODEL CONSENSUS THAT SRN ZONES WOULD BE LAST TO GET WIDESPREAD CONVECTIVE OVERTURNING...MAX TEMPS IN MID/UPPER 80S ARE POSSIBLE THERE. ALTHOUGH TEMPS SHOULD BE COOLER FARTHER NORTH...REFRAINED FROM LOWERING JUST YET AS MORE OF THE WIDESPREAD CONVECTION MAY HOLD OFF TILL AFTN. POTENTIAL FOR SVR WEATHER ALSO CONTINUES ESPECIALLY WITH NAM FORECAST HODOGRAPHS FAVORABLY CURVED AHEAD OF PREFRONTAL TROUGH/COLD FRONT FM OMAHA SWD. LIKE WHERE HEAVIER RAIN EVENTUALLY SETS UP...SEVERE WEATHER...MAINLY ANY TORNADO POTENTIAL...TOO WILL BE INFLUENCED BY EARLIER DAY CONVECTION BUT MENTION OF BOTH SVR+HEAVY RAIN WILL CONTINUE IN THE HWO. STRONGER CONVECTION COULD LINGER WELL INTO TUESDAY EVENING AND EVEN EARLY OVERNIGHT HOURS AS LOW LEVEL JET DOESN/T SHIFT SE OF THE AREA TIL AFTER 06Z PER MODELS...ALTHOUGH STRONGEST AND HEAVY RAIN THREAT BY MID EVENING SHOULD SHIFT MOSTLY TO SRN AND ERN ZONES. ALTHOUGH H85 COOLING WILL LAG DUE TO UPPER FLOW...LOWER LEVEL COOL/DRY ADVECTION WAS FAIRLY DECENT AND WITH PLENTY OF LOW CLOUDS LIKELY ON WEDNESDAY...ANY HEATING/RECOVERY WILL BE LIMITED. GENERALLY TRIMMED BACK BOTH LOWS AND HIGHS. ALTHOUGH A GENERAL TROUGHING CONTINUED ALOFT...FORCING WAS WEAK PER QG FORECAST FM GFS AND NAM BY AFTN. SO ALTHOUGH SMALL POPS WERE LEFT IN FOR THE MORNING WITH A DRY AFTN...MUCH OF ANY PRECIP SHOULD BE PRETTY LIGHT OR POSSIBLY JUST DRIZZLE. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 255 AM CDT MON SEP 8 2014 EXTENDED BEGINS QUITE COOL AS H85 TEMPS LOWER INTO LOW SINGLE DIGITS THU AND EVEN DROP BELOW ZERO THU NIGHT AS REINFORCING UPPER SHORTWAVE SENDS EVEN COLDER AIR ACROSS THE FA. THIS WAVE COULD ALSO SPREAD LIGHT SHOWERS ACROSS THE AREA THU MAKING IT EVEN LESS LIKELY TO MIX TO H85. THIS IN TURN COULD BRING EVEN COLDER MAX TEMPS TO THE REGION THAN THIS FORECAST WILL CONTAIN...WHICH WERE ALREADY NEAR OR BELOW COLDEST MAX TEMPS ON RECORD FOR SEPT 11 OF 58 IN LINCOLN...56 IN OMAHA AND 55 AT NORFOLK. IF SKIES CLEAR QUICKLY ENOUGH THURSDAY LOWS COULD BE A CATEGORY COOLER THAN THE GENERALLY 40-45 GOING BY FRIDAY MORNING AND WITH SURFACE STILL IN VICINITY SAT MORNING MORE 30S COULD BE NEEDED IN FUTURE FORECASTS THAT DAY AS WELL. OTHERWISE 00Z ECMWF INDICATED TEMPERATURES SHOULD MODERATE NEXT WEEKEND ALONG WITH PRECIP HOLDING OFF TILL NEXT WAVE SUN NIGHT. GFS WAS A LITTLE COOLER AND SUGGESTIVE OF LIGHT PRECIP SAT AS UPPER TROUGH TO BEGIN WEEKEND WAS A TOUCH MORE AMPLIFIED. FORECAST FOR NEXT SATURDAY AND SUNDAY WAS KEPT DRY FOR NOW. && .AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1217 PM CDT MON SEP 8 2014 GENERALLY VFR CONDITIONS ARE EXPECTED ACROSS EASTERN NEBRASKA TAF SITES THROUGH 18Z TUESDAY. SCATTERED SHOWERS IN NORTHEAST NEBRASKA COULD AFFECT KOFK FOR A FEW HOURS THIS AFTERNOON. THEN THERE IS A SMALL CHANCE THUNDERSTORMS COULD DEVELOP BY 00Z THIS EVENING...BUT MOST OF THAT ACTIVITY IS EXPECTED TO FIRE SOUTHEAST OF KOMA AND KLNK. AN INCREASE OF MID LEVEL CLOUDS IS EXPECTED LATE TONIGHT AND TUESDAY AHEAD OF A STORM SYSTEM MOVING INTO THE PLAINS. WIDESPREAD THUNDERSTORMS ARE FORECAST AFTER THE END OF THIS TAF CYCLE. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ UPDATE...DERGAN SHORT TERM...CHERMOK LONG TERM...CHERMOK AVIATION...DERGAN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
701 AM CDT MON SEP 8 2014 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 255 AM CDT MON SEP 8 2014 HOW FAR SOUTH INTO THE FA WILL MORNING CONVECTION MAKE IT AND THEN HOW QUICKLY WILL CONVECTION DEVELOP ON TUESDAY MAIN FORECAST FOCUS IN THE SHORT TERM...ALTHOUGH SEVERE WEATHER AND HEAVY RAIN REMAIN IN THE PICTURE FOR LATE TUESDAY. A MERGING THUNDERSTORM CLUSTER WAS WORKING TOWARD NERN NEBR AS OF 8Z BUT ALSO MOVING INTO MLCAPE VALUE AREAS THAT WERE LESS THAN 500 J/KG PER SPC MESO PAGE. THUS WOULD SUSPECT SOME WEAKENING ON SE EDGE THIS MORNING WHICH WAS HINTED AT BY 05Z HRRR AND RAP WHICH KEPT MOST OF THE PRECIP IN FAR NE ZONES OR EVEN NE OF THERE...AS DID 00Z ECMWF. HOWEVER...THAT SAID CONVECTION WAS MAINTAINING ITS STRENGTH ENOUGH TO DISCOUNT SHORT TERM MODELS TO SOME DEGREE AND TO INCREASE POPS IN NERN ZONES THIS MORNING AND KEEP MENTION OF THEM PER PREV FORECAST IN THE AFTN ALONG E OF MO RIVER. DON/T KNOW IF IT WILL HOLD TOGETHER AND ROLL DOWN MO RIVER TO OMAHA...BUT CAN/T RULE THAT OUT ATTM. ALSO SOME HINT BY NAM AND 4KM WRF THAT SOME NEW DEVELOPMENT COULD OCCUR ON SW SIDE THIS MORNING AND THUS LEFT IN SMALL POPS FARTHER SW THAN RAP/HRRR WOULD SUGGEST. STILL COUNTING ON DEBRIS BEING MINIMAL ENOUGH THIS AFTN TO ALLOW MAX TEMPS TO REACH 80 OR BETTER ALL BUT PERHAPS FAR NERN ZONES. ALTHOUGH SOME SMALL POPS WERE MAINTAINED TONIGHT...STILL APPEARED THAT MAIN CONVECTIVE AREAS WOULD EITHER BE TO OUR EAST ON NOSE OF H85 THETAE RIDGE/JET OR TO OUR WEST AS UPPER TROUGH AND MID LEVEL MOISTURE APPROACH. THIS MOISTURE...WITH H7 DWPTS FORECAST AT 8-10 DEG C PER NAM/GFS...COULD ALLOW CONVECTION TO START OR INCREASE FAIRLY EARLY TUESDAY AFTN AND LEAD TO LOCALLY HEAVY RAIN BY EVENING AS PWATS WILL BE HIGH AND TRAINING OF CELLS PROBABLE. HOWEVER...A LOT COULD/WILL DEPEND ON INITIAL DEVELOPMENT AND RESULTANT OUTFLOW OR DIFFERENTIAL HEATING AREAS AND WILL REFRAIN FROM BLANKET HEAVY RAIN MENTION JUST YET. WITH GENERAL MODEL CONSENSUS THAT SRN ZONES WOULD BE LAST TO GET WIDESPREAD CONVECTIVE OVERTURNING...MAX TEMPS IN MID/UPPER 80S ARE POSSIBLE THERE. ALTHOUGH TEMPS SHOULD BE COOLER FARTHER NORTH...REFRAINED FROM LOWERING JUST YET AS MORE OF THE WIDESPREAD CONVECTION MAY HOLD OFF TILL AFTN. POTENTIAL FOR SVR WEATHER ALSO CONTINUES ESPECIALLY WITH NAM FORECAST HODOGRAPHS FAVORABLY CURVED AHEAD OF PREFRONTAL TROUGH/COLD FRONT FM OMAHA SWD. LIKE WHERE HEAVIER RAIN EVENTUALLY SETS UP...SEVERE WEATHER...MAINLY ANY TORNADO POTENTIAL...TOO WILL BE INFLUENCED BY EARLIER DAY CONVECTION BUT MENTION OF BOTH SVR+HEAVY RAIN WILL CONTINUE IN THE HWO. STRONGER CONVECTION COULD LINGER WELL INTO TUESDAY EVENING AND EVEN EARLY OVERNIGHT HOURS AS LOW LEVEL JET DOESN/T SHIFT SE OF THE AREA TIL AFTER 06Z PER MODELS...ALTHOUGH STRONGEST AND HEAVY RAIN THREAT BY MID EVENING SHOULD SHIFT MOSTLY TO SRN AND ERN ZONES. ALTHOUGH H85 COOLING WILL LAG DUE TO UPPER FLOW...LOWER LEVEL COOL/DRY ADVECTION WAS FAIRLY DECENT AND WITH PLENTY OF LOW CLOUDS LIKELY ON WEDNESDAY...ANY HEATING/RECOVERY WILL BE LIMITED. GENERALLY TRIMMED BACK BOTH LOWS AND HIGHS. ALTHOUGH A GENERAL TROUGHING CONTINUED ALOFT...FORCING WAS WEAK PER QG FORECAST FM GFS AND NAM BY AFTN. SO ALTHOUGH SMALL POPS WERE LEFT IN FOR THE MORNING WITH A DRY AFTN...MUCH OF ANY PRECIP SHOULD BE PRETTY LIGHT OR POSSIBLY JUST DRIZZLE. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 255 AM CDT MON SEP 8 2014 EXTENDED BEGINS QUITE COOL AS H85 TEMPS LOWER INTO LOW SINGLE DIGITS THU AND EVEN DROP BELOW ZERO THU NIGHT AS REINFORCING UPPER SHORTWAVE SENDS EVEN COLDER AIR ACROSS THE FA. THIS WAVE COULD ALSO SPREAD LIGHT SHOWERS ACROSS THE AREA THU MAKING IT EVEN LESS LIKELY TO MIX TO H85. THIS IN TURN COULD BRING EVEN COLDER MAX TEMPS TO THE REGION THAN THIS FORECAST WILL CONTAIN...WHICH WERE ALREADY NEAR OR BELOW COLDEST MAX TEMPS ON RECORD FOR SEPT 11 OF 58 IN LINCOLN...56 IN OMAHA AND 55 AT NORFOLK. IF SKIES CLEAR QUICKLY ENOUGH THURSDAY LOWS COULD BE A CATEGORY COOLER THAN THE GENERALLY 40-45 GOING BY FRIDAY MORNING AND WITH SURFACE STILL IN VICINITY SAT MORNING MORE 30S COULD BE NEEDED IN FUTURE FORECASTS THAT DAY AS WELL. OTHERWISE 00Z ECMWF INDICATED TEMPERATURES SHOULD MODERATE NEXT WEEKEND ALONG WITH PRECIP HOLDING OFF TILL NEXT WAVE SUN NIGHT. GFS WAS A LITTLE COOLER AND SUGGESTIVE OF LIGHT PRECIP SAT AS UPPER TROUGH TO BEGIN WEEKEND WAS A TOUCH MORE AMPLIFIED. FORECAST FOR NEXT SATURDAY AND SUNDAY WAS KEPT DRY FOR NOW. && .AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 655 AM CDT MON SEP 8 2014 PRIMARY AREA OF CONVECTION IS EXPECTED TO REMAIN NORTH AND EAST OF TAF SITES THROUGH 18Z. MID LEVEL VFR CIGS LIKELY DURING THIS TIME AT BOTH KOFK AND KOMA. VFR CONDITIONS SHOULD PREVAIL THROUGH THE PERIOD. SOME CHANCE OF MORE STORMS MOVING IN FROM THE SOUTH AFTER 06Z ESPECIALLY AT KLNK AS NEXT POCKET OF INSTABILITY LIFTS NORTH WITH THE WARM FRONT. NO MENTION AT THIS TIME DUE TO UNCERTAINTY SO LATE IN THE PERIOD. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...CHERMOK LONG TERM...CHERMOK AVIATION...FOBERT
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
304 AM CDT MON SEP 8 2014 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 255 AM CDT MON SEP 8 2014 HOW FAR SOUTH INTO THE FA WILL MORNING CONVECTION MAKE IT AND THEN HOW QUICKLY WILL CONVECTION DEVELOP ON TUESDAY MAIN FORECAST FOCUS IN THE SHORT TERM...ALTHOUGH SEVERE WEATHER AND HEAVY RAIN REMAIN IN THE PICTURE FOR LATE TUESDAY. A MERGING THUNDERSTORM CLUSTER WAS WORKING TOWARD NERN NEBR AS OF 8Z BUT ALSO MOVING INTO MLCAPE VALUE AREAS THAT WERE LESS THAN 500 J/KG PER SPC MESO PAGE. THUS WOULD SUSPECT SOME WEAKENING ON SE EDGE THIS MORNING WHICH WAS HINTED AT BY 05Z HRRR AND RAP WHICH KEPT MOST OF THE PRECIP IN FAR NE ZONES OR EVEN NE OF THERE...AS DID 00Z ECMWF. HOWEVER...THAT SAID CONVECTION WAS MAINTAINING ITS STRENGTH ENOUGH TO DISCOUNT SHORT TERM MODELS TO SOME DEGREE AND TO INCREASE POPS IN NERN ZONES THIS MORNING AND KEEP MENTION OF THEM PER PREV FORECAST IN THE AFTN ALONG E OF MO RIVER. DON/T KNOW IF IT WILL HOLD TOGETHER AND ROLL DOWN MO RIVER TO OMAHA...BUT CAN/T RULE THAT OUT ATTM. ALSO SOME HINT BY NAM AND 4KM WRF THAT SOME NEW DEVELOPMENT COULD OCCUR ON SW SIDE THIS MORNING AND THUS LEFT IN SMALL POPS FARTHER SW THAN RAP/HRRR WOULD SUGGEST. STILL COUNTING ON DEBRIS BEING MINIMAL ENOUGH THIS AFTN TO ALLOW MAX TEMPS TO REACH 80 OR BETTER ALL BUT PERHAPS FAR NERN ZONES. ALTHOUGH SOME SMALL POPS WERE MAINTAINED TONIGHT...STILL APPEARED THAT MAIN CONVECTIVE AREAS WOULD EITHER BE TO OUR EAST ON NOSE OF H85 THETAE RIDGE/JET OR TO OUR WEST AS UPPER TROUGH AND MID LEVEL MOISTURE APPROACH. THIS MOISTURE...WITH H7 DWPTS FORECAST AT 8-10 DEG C PER NAM/GFS...COULD ALLOW CONVECTION TO START OR INCREASE FAIRLY EARLY TUESDAY AFTN AND LEAD TO LOCALLY HEAVY RAIN BY EVENING AS PWATS WILL BE HIGH AND TRAINING OF CELLS PROBABLE. HOWEVER...A LOT COULD/WILL DEPEND ON INITIAL DEVELOPMENT AND RESULTANT OUTFLOW OR DIFFERENTIAL HEATING AREAS AND WILL REFRAIN FROM BLANKET HEAVY RAIN MENTION JUST YET. WITH GENERAL MODEL CONSENSUS THAT SRN ZONES WOULD BE LAST TO GET WIDESPREAD CONVECTIVE OVERTURNING...MAX TEMPS IN MID/UPPER 80S ARE POSSIBLE THERE. ALTHOUGH TEMPS SHOULD BE COOLER FARTHER NORTH...REFRAINED FROM LOWERING JUST YET AS MORE OF THE WIDESPREAD CONVECTION MAY HOLD OFF TILL AFTN. POTENTIAL FOR SVR WEATHER ALSO CONTINUES ESPECIALLY WITH NAM FORECAST HODOGRAPHS FAVORABLY CURVED AHEAD OF PREFRONTAL TROUGH/COLD FRONT FM OMAHA SWD. LIKE WHERE HEAVIER RAIN EVENTUALLY SETS UP...SEVERE WEATHER...MAINLY ANY TORNADO POTENTIAL...TOO WILL BE INFLUENCED BY EARLIER DAY CONVECTION BUT MENTION OF BOTH SVR+HEAVY RAIN WILL CONTINUE IN THE HWO. STRONGER CONVECTION COULD LINGER WELL INTO TUESDAY EVENING AND EVEN EARLY OVERNIGHT HOURS AS LOW LEVEL JET DOESN/T SHIFT SE OF THE AREA TIL AFTER 06Z PER MODELS...ALTHOUGH STRONGEST AND HEAVY RAIN THREAT BY MID EVENING SHOULD SHIFT MOSTLY TO SRN AND ERN ZONES. ALTHOUGH H85 COOLING WILL LAG DUE TO UPPER FLOW...LOWER LEVEL COOL/DRY ADVECTION WAS FAIRLY DECENT AND WITH PLENTY OF LOW CLOUDS LIKELY ON WEDNESDAY...ANY HEATING/RECOVERY WILL BE LIMITED. GENERALLY TRIMMED BACK BOTH LOWS AND HIGHS. ALTHOUGH A GENERAL TROUGHING CONTINUED ALOFT...FORCING WAS WEAK PER QG FORECAST FM GFS AND NAM BY AFTN. SO ALTHOUGH SMALL POPS WERE LEFT IN FOR THE MORNING WITH A DRY AFTN...MUCH OF ANY PRECIP SHOULD BE PRETTY LIGHT OR POSSIBLY JUST DRIZZLE. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 255 AM CDT MON SEP 8 2014 EXTENDED BEGINS QUITE COOL AS H85 TEMPS LOWER INTO LOW SINGLE DIGITS THU AND EVEN DROP BELOW ZERO THU NIGHT AS REINFORCING UPPER SHORTWAVE SENDS EVEN COLDER AIR ACROSS THE FA. THIS WAVE COULD ALSO SPREAD LIGHT SHOWERS ACROSS THE AREA THU MAKING IT EVEN LESS LIKELY TO MIX TO H85. THIS IN TURN COULD BRING EVEN COLDER MAX TEMPS TO THE REGION THAN THIS FORECAST WILL CONTAIN...WHICH WERE ALREADY NEAR OR BELOW COLDEST MAX TEMPS ON RECORD FOR SEPT 11 OF 58 IN LINCOLN...56 IN OMAHA AND 55 AT NORFOLK. IF SKIES CLEAR QUICKLY ENOUGH THURSDAY LOWS COULD BE A CATEGORY COOLER THAN THE GENERALLY 40-45 GOING BY FRIDAY MORNING AND WITH SURFACE STILL IN VICINITY SAT MORNING MORE 30S COULD BE NEEDED IN FUTURE FORECASTS THAT DAY AS WELL. OTHERWISE 00Z ECMWF INDICATED TEMPERATURES SHOULD MODERATE NEXT WEEKEND ALONG WITH PRECIP HOLDING OFF TILL NEXT WAVE SUN NIGHT. GFS WAS A LITTLE COOLER AND SUGGESTIVE OF LIGHT PRECIP SAT AS UPPER TROUGH TO BEGIN WEEKEND WAS A TOUCH MORE AMPLIFIED. FORECAST FOR NEXT SATURDAY AND SUNDAY WAS KEPT DRY FOR NOW. && .AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1145 PM CDT SUN SEP 7 2014 VFR CONDS ARE STILL EXPECTED THROUGH THE PERIOD. THERE REMAINS AN ISO CHC OF A SHRA/TSRA LATE TONIGHT AND INTO MON MRNG AT MAINLY KOFK/KOMA BUT THREAT IS TO LOW TO INCLUDE IN THE TAFS ATTM. OTHERWISE SOUTH WINDS ARE STILL EXPECTED TO INCREASE ON MON WITH GUSTS AT ALL 3 SITES. WINDS WILL DIMINISH BY MON EVENING. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...CHERMOK LONG TERM...CHERMOK AVIATION...BOUSTEAD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
325 PM EDT MON SEP 8 2014 .SYNOPSIS... WET WEATHER WILL CONTINUE OVERNIGHT AS LOW PRESSURE DRAGS MORE TROPICAL MOISTURE UP ALONG A STALLED FRONT. DRIER AIR WILL FINALLY ARRIVE ON TUESDAY AS LOW PRESSURE MOVES FURTHER UP THE MID-ATLANTIC COAST. WARMER TEMPERATURES AND DRY WEATHER ARE EXPECTED WEDNESDAY AND THURSDAY. A STRONG COLD FRONT WILL ARRIVE LATE WEEK. THE FRONT WILL MOVE INTO THE REGION BY THE WEEKEND BEFORE DRIFTING SOUTH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... AS OF 3 PM MONDAY...WEAK LOW PRESSURE IS VERY SLOWLY MOVING NORTHEASTWARD ALONG A FRONT STALLED NEAR INTERSTATE 95. THE LOW APPEARS TO BE LOCATED NEAR DILLON AND SHOULD MOVE TOWARD FAYETTEVILLE OVER THE NEXT 3 HOURS. WHILE THIS WILL REMOVE THE STRONGEST LOW-LEVEL CONVERGENCE AND FOCUS FOR SHOWERS...WE STILL HAVE A DEEP SOUTHERLY FLOW OF MOISTURE TO DEAL WITH. PRECIPITABLE WATER VALUES REMAIN 2.2 INCHES INLAND TO 2.4 INCHES ALONG THE COAST. GIVEN COOL SURFACE TEMPERATURES THE BULK OF OUR INSTABILITY IS ELEVATED...500 J/KG INLAND TO NEAR 1000 J/KG AT THE COAST. MODERATE TO HEAVY RAIN WILL CONTINUE ACROSS INTERIOR SE NORTH CAROLINA AND NEARBY PORTIONS OF INTERIOR NE SOUTH CAROLINA FOR THE NEXT FEW HOURS. THE FOCUS FOR HEAVY RAIN AFTER DARK WILL PROBABLY SHIFT OFFSHORE SOUTH OF OAK ISLAND...ADVECTING BACK ONSHORE IN THE DEEP SOUTHERLY FLOW. FOR THIS REASON WE WILL MAINTAIN THE FLOOD WATCH FROM LUMBERTON AND DILLON EASTWARD TOWARD SOUTHPORT AND WILMINGTON. SOILS ARE SATURATED OVER MOST OF THE WATCH AREA AND ANY SUSTAINED HEAVY RAINFALL WILL CREATE A FLOODING RISK. WE HAVE RECEIVED SEVERAL PUBLIC REPORTS VIA FACEBOOK AND PHONE OF 5+ INCHES OF RAIN MEASURED ACROSS NORTHEASTERN NEW HANOVER COUNTY SO FAR IN THIS EVENT. MODELS HAVE COME INTO BETTER AGREEMENT WITH HOW THE EVENT ENDS TONIGHT...ALTHOUGH THE LAST SEVERAL HRRR RUNS ARE MUCH FASTER WITH CLEARING THE BACK EDGE OF THE PRECIP OFF THE COAST THAN ANY OF THE SYNOPTIC GUIDANCE. (GFS, NAM, ECMWF) BY 8 PM I WOULD EXPECT MOST OF THE RAIN TO HAVE ENDED WEST OF I-95 EXCEPT NEAR LUMBERTON...AND BY MIDNIGHT THE BACK EDGE OF PRECIP WILL PROBABLY BE THROUGH MYRTLE BEACH AND WHITEVILLE. IT MAY TAKE UNTIL SUNRISE FOR RAIN TO END IN WILMINGTON HOWEVER AS THE EASTWARD PROGRESSION OF THE MID-LEVEL TROUGH BECOMES QUITE SLOW. LOWS SHOULD RANGE FROM THE UPPER 60S INLAND TO THE LOWER 70S NEAR THE COAST. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...LOW PRESSURE WILL BE DEPARTING NORTHEAST TUE MORNING WITH MID LEVEL DRY AIR MOVING IN FROM THE WEST-NORTHWEST. THIS SHOULD BRING ABOUT A FAIRLY QUICK END TO ANY LINGER PRECIP TUE MORNING FOR INLAND SITES. ALONG THE COAST MEASURABLE PRECIP MAY HANG ON INTO EARLY AFTERNOON WITH LOW LEVEL MOISTURE TRAPPED UNDER MID LEVEL SUBSIDENCE IN THE WAKE OF THE LOW AND ASSOCIATED WITH THE SLOWLY EXPANDING SOUTHERN CONUS 5H RIDGE. CLOUD COVER WILL ALSO LINGER ACROSS THE AREA TUE. GRADUAL CLEARING WILL OCCUR FROM WEST TO EAST IN THE AFTERNOON BUT THE NC COAST IS LIKELY TO REMAIN CLOUDY THROUGH SUNSET. TEMPERATURES WILL BE A MIXED BAG WITH INLAND AREAS RUNNING WARMER DUE TO BREAKS OF SUN LATER IN THE DAY AND SUBTLE HEIGHT INCREASES. ALONG THE COAST HIGHS WILL BE NEAR TO SLIGHTLY BELOW CLIMO. CLEARING LATE TUE NIGHT COULD ALLOW FOR A PERIOD OF LOW STRATUS OR FOG JUST BEFORE DAYBREAK. LATE CLOUD/FOG WILL HELP KEEP LOWS NEAR CLIMO TUE NIGHT. MODIFIED HIGH PRESSURE WILL BUILD IN FROM THE WEST ON WED AS MID LEVEL RIDGE OVER THE SOUTH CONTINUES TO EXPAND EAST. FORECAST SOUNDINGS SHOW DEEP DRY AIR BUILDING IN...WHICH SHOULD PRODUCE PARTLY TO MOSTLY SUNNY SKIES. DEEP DRY AIR ALONG WITH WESTERLY FLOW ALOFT AND LOW LEVEL NORTHEAST FLOW WILL PREVENT DEVELOPMENT OF ANY MEANINGFUL CONVECTION WED AND PRECIP CHANCES WILL BE NEAR ZERO. AFOREMENTIONED NORTHEAST FLOW IN THE BOUNDARY LAYER WILL KEEP HIGHS ALONG THE COAST A LITTLE COOLER...THOUGH STILL ABOVE CLIMO. TEMPS WED AFTERNOON WILL RANGE FROM LOW 90S INLAND SC TO MID 80S ALONG THE NC COAST. WEAK WARM ADVECTION DEVELOPS WED NIGHT AS SURFACE RIDGE AXIS SHIFTS OFFSHORE. SOME MOISTURE RETURN ALONG WITH LIGHT BOUNDARY LAYER FLOW MAY ALLOW DEVELOPMENT OF FOG LATE IN THE PERIOD. LIGHT RETURN FLOW AND POTENTIAL FOG WILL KEEP LOWS A LITTLE ABOVE CLIMO. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 3 PM MONDAY...WEAK HIGH PRESSURE WILL REMAIN OVER THE AREA EARLY THURS AS RIDGE HOLDS ON ALOFT...BUT BY LATE THURS INTO FRIDAY A COLD FRONT WILL MOVE INTO THE CAROLINAS. SHOULD REMAIN DRY FOR THURS AT LEAST OVER MOST OF AREA BUT BY THURS NIGHT INTO FRI...EXPECT INCREASED SHOWER AND THUNDERSTORM ACTIVITY AS FRONT MOVES THROUGH THE CAROLINAS. PCP WATER VALUES AS LOW AS 1.4 INCHES THURS MORNING WILL RAMP UP GREATER THAN 2 INCHES JUST AHEAD AND ALONG COLD FRONT AS IT MOVES SOUTH THROUGH FRI. LOOKS LIKE FRONT WILL GET HUNG UP OVER THE COAST THROUGH AT LEAST SATURDAY AS SHORTWAVE LIFTS OFF TO THE NORTHEAST LEAVING A BROAD TROUGH OF LOW PRESSURE IN THE MID TO UPPER LEVELS. THIS MAINTAINS A SW FLOW ALOFT RUNNING PARALLEL TO THE FRONT AND MAY KEEP FRONT HUNG UP OVER OR NEARBY AREA THROUGH MUCH OF THE WEEKEND. A MORE VIGOROUS SHORTWAVE MAY REACH FAR ENOUGH SOUTH TO GIVE FRONT A PUSH OFF SHORE BY THE LATTER HALF OF THE WEEKEND. OVERALL EXPECT CLOUDS AND PCP IN FORECAST FOR MUCH OF FRI AND SATURDAY WITH SOME CLEARING BY LATE SUNDAY INTO MONDAY AS HIGH PRESSURE BUILDS DOWN FROM THE NORTH. NOT A HIGH CONFIDENCE FORECAST IN TERMS OF HOW FAR SOUTH THE FRONT WILL INITIALLY MAKE IT BEFORE STALLING. TOUGH WIND FORECAST WITH SOUTHERLY WINDS AHEAD OF FRONT THURS INTO FRI BUT MAY SEE WINDS BECOME VARIABLE OR NORTH AS FRONT REACHES INTO AREA OVER THE WEEKEND. EXPECT TEMPS UP AROUND 90 OR SO ON THURS...BUT BY FRI INTO SATURDAY CLOUDS AND SHWRS WILL AFFECT THE TEMPS AND THEN SOME COOLER AIR WILL BEGIN TO MOVE IN BEHIND FRONT LATER ON SATURDAY INTO SUNDAY...KEEPING TEMPS IN THE LOWER 80S OVER THE WEEKEND INTO EARLY NEXT WEEK. WILL SEE SOME READINGS IN THE 70S FOR HIGHS INLAND WITH COMBINATION OF COOLER AIR MOVING IN FROM THE N-NW AND CLOUDS AND PCP OVER THE AREA LATE OVER THE WEEKEND. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... AS OF 18Z...AT KFLO/KLBT IFR/TEMPO LIFR WILL CONTINUE AT LEAST INTO THE EARLY EVENING HOURS. GRADUAL IMPROVEMENT IN VSBYS EXPECTED THIS AFTERNOON AS RA ENDS FROM W-E AND WINDS BECOME N. AT THE COASTAL TERMINALS VFR/TEMPO MVFR EXPECTED WITH PREDOMINATE SHRA. ISOLATED TSRA POSSIBLE BUT WILL NOT INCLUDE IN TAFS ATTM. DUE TO QUICK MOVEMENT OF ISOLATED HEAVIER SHRA BRIEF PERIODS OF IFR POSSIBLE AT COASTAL TERMINALS. AT THE COASTAL TERMINALS WINDS WILL BE S-SW AND GUSTY...EXCEPT LIGHT SE AT KILM. PRECIPITATION ENDS COASTAL TERMINALS THIS EVENING. IFR WILL IMPROVE TO MVFR KFLO/KLBT OVERNIGHT AS WEAK HIGH PRESSURE/SUBSIDENCE BUILDS IN. SOME IFR POSSIBLE COASTAL TERMINALS OVERNIGHT. SUB-VFR CONDITIONS IMPROVE TO VFR MID MORNING AT KFLO/KLBT AND COASTAL TERMINALS LATE IN THE TAF VALID PERIOD AS WINDS BECOME WESTERLY. EXTENDED OUTLOOK...CHANCE OF SHOWERS EARLY TUESDAY. OTHERWISE VFR WILL DEVELOP TUESDAY AND PERSIST THROUGH THURSDAY. SHOWERS/TSTMS RETURN ON FRIDAY AS ANOTHER COLD FRONT APPROACHES THE TERMINALS. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM MONDAY...LOW PRESSURE IS MOVING NORTHEAST ALONG A NEARLY STATIONARY FRONT NEAR INTERSTATE 95 AND SHOULD PUSH INTO NORTHEASTERN NORTH CAROLINA LATE TONIGHT. THIS WILL DRAG THE FRONT DOWN TOWARD THE COAST WITH WINDS VEERING MORE WESTERLY LATE ALONG THE SOUTH CAROLINA COAST. ALTHOUGH RAINFALL INTENSITY HAS REALLY DIMINISHED THIS AFTERNOON...ADDITIONAL WAVES OF SHOWERS AND THUNDERSTORMS WILL PROBABLY DEVELOP LATER THIS EVENING AND AFFECT THE AREA OVERNIGHT...MOST NUMEROUS IN THE CAPE FEAR WATERS TOWARD AND AFTER MIDNIGHT. SOUTH WINDS AHEAD OF THE INLAND LOW INCREASED TO AROUND 20 KNOTS ALONG THE SOUTH CAROLINA COAST EARLIER TODAY WITH 25 KNOT GUSTS. WIND SPEEDS ALONG THE SOUTH CAROLINA COAST HAVE PEAKED AND SHOULD DIMINISH GRADUALLY THROUGH THE NIGHT. ALONG THE NC COAST THE STRONGEST SOUTH WINDS WILL BEGIN TO RAMP UP SHORTLY BUT WILL PROBABLY ONLY EXCEED 15 KNOTS FOR A FEW HOURS AROUND MIDNIGHT. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...EXITING LOW PRESSURE WILL SLOWLY PUSH THE STALLED FRONT OFF THE COAST DURING TUE. SOUTHWEST FLOW AT THE START OF THE PERIOD WILL GRADUALLY VEER TO WEST-NORTHWEST LATER TUE AND TUE NIGHT. GRADIENT REMAINS WEAK AND THE LACK OF ANY COLD PUSH WILL KEEP WIND SPEEDS 10 KT OR LESS BOTH PRE AND POST FRONT. ELONGATED SURFACE HIGH BUILDS IN FROM THE WEST WED WITH WINDS VEERING TO NORTHERLY DURING THE DAY. LATE IN THE DAY SURFACE RIDGE AXIS MOVES OVERHEAD WITH NORTHERLY FLOW UNDER 10 KT BECOMING LIGHT AND HIGHLY VARIABLE. WEAK RETURN FLOW DEVELOPS LATE IN THE PERIOD AS THE SURFACE HIGH SHIFTS EAST OF THE WATERS. SEAS 3 TO 4 FT WILL CARRY OVER FROM THE PREVIOUS FORECAST PERIOD BUT WILL QUICKLY DROP TO 2 TO 3 FT TUE DUE TO THE COMBINATION OF LIGHT WINDS AND OFFSHORE FLOW. FURTHER REDUCTION IN SEAS IS ANTICIPATED ON WED. LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 300 PM MONDAY...SOUTHERLY WINDS WILL INCREASE THROUGH THURS BETWEEN BERMUDA HIGH AND COLD FRONT MAKING ITS WAY INTO THE CAROLINAS....BUT OVERALL EXPECT WINDS TO REMAIN BELOW 15 KTS. MUCH UNCERTAINTY EXISTS AS TO HOW FAR THE FRONT WILL REACH BEFORE STALLING AND THEREFORE WILL MAINTAIN SOUTHERLY WINDS THROUGH EARLY SATURDAY. BY LATE SATURDAY INTO SUNDAY WINDS SHOULD COME AROUND TO THE NE TO N AS FRONT GETS A PUSH SOUTHWARD. WILL SHOW A NORTHERLY SURGE UP TO 15 KTS BY SUN MORNING BUT THIS IS ALL DEPENDENT ON HOW FAR SOUTH THE COLD FRONT MAKES IT AND HOW MUCH COLD AIR BLEEDS SOUTH INTO THE WATERS. SEAS OF 2 TO 3 FT MAY INCREASE UP TO 3 TO 4 FT IN INCREASED SOUTHERLY FLOW BY SATURDAY AND MAY SEE A BIT MORE OF AN INCREASE BY SUNDAY IN COOLER NORTHERLY FLOW BEHIND FRONT. && .TIDES/COASTAL FLOODING... AS OF 3 PM MONDAY...A LARGE POSITIVE TIDAL ANOMALY ON THE LOWER CAPE FEAR RIVER AROUND +0.75 FEET SHOULD ALLOW THE RIVER TO FLOOD AT HIGH TIDE THIS EVENING AND AGAIN TUESDAY MORNING. THE REASONS FOR THIS ARE ASTRONOMICAL (FULL MOON)...METEOROLOGICAL (RECENT HEAVY RAIN AND STEADY SOUTH WINDS)...AND NON-METEOROLOGICAL (DEEP DREDGING IN THE RIVER CHANNEL.) THE COASTAL FLOOD ADVISORY FOR THE LOWER CAPE FEAR RIVER WILL EXTEND ACROSS THE NEXT TWO HIGH TIDES...10 PM THIS EVENING AND 1030 AM TUESDAY MORNING. THE TIDAL ANOMALY MEASURED AT THE MYRTLE BEACH AND WRIGHTSVILLE BEACH GAUGES APPEARS TO BE DECREASING AS WINDS VEER MORE SOUTH-SOUTHWESTERLY AND WIND STRESS FORCING (EKMAN SPIRAL) PUSHES LESS WATER UP AGAINST THE SHORELINE. ASSUMING TIDAL ANOMALIES REMAIN +0.3 FEET OR LESS WE SHOULD REMAIN BELOW COASTAL FLOODING CRITERIA. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR SCZ024. NC...FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR NCZ087. FLOOD WATCH THROUGH TUESDAY MORNING FOR NCZ096-099-105>110. COASTAL FLOOD ADVISORY FROM 8 PM THIS EVENING TO NOON EDT TUESDAY FOR NCZ107. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...III LONG TERM...RGZ AVIATION...MRR TIDES/COASTAL FLOODING...TRA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1246 PM EDT MON SEP 8 2014 .SYNOPSIS... WET WEATHER IS EXPECTED TODAY AS LOW PRESSURE DRAGS TROPICAL MOISTURE UP ALONG A FRONT THAT HAS STALLED OVER THE EASTERN CAROLINAS. DRIER AIR BUILDING IN TUESDAY WILL ALLOW FOR A WARMING TREND WEDNESDAY AND THURSDAY. A FAIRLY ROBUST COLD FRONT MAY ARRIVE FRIDAY NIGHT OR SATURDAY. THE COLD FRONT WILL MOVE OFF THE COAST SATURDAY NIGHT WITH HIGH PRESSURE BUILDING IN FROM THE NORTH FOR SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 100 PM MONDAY...RECENT MESOANALYSIS SHOWED 1016 MB LOW PRESSURE JUST SOUTHWEST OF FLORENCE. THE LOW IS FIRMLY ATTACHED TO THE FRONT AND SHOULD SLOWLY MOVE NORTHEASTWARD ALONG THE BOUNDARY THROUGH THE AFTERNOON AND EVENING HOURS. PRECIPITATION IS DRYING UP BEHIND THE LOW AND THE LAST SEVERAL HRRR RUNS SHOW THIS MAY ACTUALLY BE THE BACK EDGE OF THE EVENT. I HAVE UPDATED POP GRIDS THROUGH TONIGHT TO LOWER POPS ACROSS MUCH OF INTERIOR SOUTH CAROLINA PLUS ROBESON COUNTY NC OVERNIGHT. ALONG THE COAST THE MOISTURE CONVEYOR CONTINUES AND SHOULD RESULT IN MULTIPLE WAVES OF SHOWERS AND THUNDERSTORMS CONTINUING. PREVIOUS DISCUSSION FROM 1000 AM FOLLOWS... AFTER COLLABORATION WITH SURROUNDING NWS OFFICES AND THE NESDIS SATELLITE PRECIPITATION BRANCH WE HAVE ISSUED A FLOOD WATCH FOR ALL OF SOUTHEASTERN NORTH CAROLINA PLUS MARLBORO...DARLINGTON AND DILLON COUNTIES IN SOUTH CAROLINA. THIS DELINEATION WAS CHOSEN BASED ON GAUGE-MEASURED AND RADAR-OBSERVED RAINFALL OVER THE PAST 24 HOURS PLUS FORECAST RAINFALL AMOUNTS OF 1-2 INCHES WITH ISOLATED 4-5 INCH AMOUNTS IN THE NEXT 12-24 HOURS. THE REGIONS AT HIGHEST RISK FOR FLOODING ARE JUST NORTH OF FLORENCE FOR THE NEXT 4-8 HOURS AS SLOW-MOVING SHOWERS PIVOT AROUND THE NORTH SIDE OF THE LOW...AND THEN TONIGHT ACROSS COASTAL NEW HANOVER AND PENDER COUNTIES AS HEAVY RAIN SHOULD PUSH ONSHORE AHEAD OF THE APPROACHING LOW. THESE ARE ALSO THE TWO REGIONS THAT ALREADY HAVE PICKED UP 3-4 INCHES OF RAIN AND REALISTICALLY COULD NOT HANDLE MORE THAN ANOTHER 1.0 TO 1.5 INCHES OF RAIN IN AN HOUR WITHOUT CAUSING FLOODING. A STALLED FRONT LOCATED ROUGHLY FROM CLINTON TO FAYETTEVILLE... LAURINBURG...DARLINGTON AND SUMTER HAS ACTUALLY BACKED UP TO THE NORTH A LITTLE EARLY THIS MORNING. THIS IS PROBABLY DUE TO SOUTHERLY WINDS EAST OF SURFACE LOW BETWEEN SUMTER AND ORANGEBURG. THIS LOW SHOULD SLOWLY ADVANCE ITS WAY NORTHEASTWARD TODAY AND TONIGHT. BROAD LOW-LEVEL CONVERGENCE NEAR THIS LOW COUPLED WITH MORE FOCUSED CONVERGENCE ALONG THE FRONT...PLUS FRICTIONAL CONVERGENCE OF ONSHORE WINDS ALONG THE COAST SHOULD KEEP PLENTY OF SHOWERS AND THUNDERSTORMS FIRING THROUGHOUT THE DAY. IN THE UPPER LEVELS A SERIES OF WEAK UPPER DISTURBANCES MOVING ACROSS THE CENTRAL APPALACHIANS AND VIRGINIA WILL HELP ACCELERATE THE JET STREAM FLOW ACROSS THE COASTAL MID-ATLANTIC STATES...PLACING THE EASTERN CAROLINAS WITHIN THE FAVORABLE RIGHT-ENTRANCE REGION OF THIS JET MAX. THE SUBSEQUENT UPPER DIVERGENCE WILL HELP ENHANCE OUR OVERALL SYNOPTIC LIFT ACROSS THE AREA. THE AIRMASS IS ALREADY CONDITIONALLY UNSTABLE WITH ELEVATED CAPE RANGING FROM 500 J/KG INLAND TO NEARLY 2000 J/KG ON THE COAST. THERE WON`T BE A LOT OF DAYTIME HEATING TODAY GIVEN THICK CLOUDS AND PRECIP...BUT ASSUMING WE CAN PUSH SURFACE TEMPS TO 80 THIS INSTABILITY WILL BECOME SURFACE-BASED. HIGHS SHOULD RANGE FROM THE UPPER 70S WEST OF I-95...TO 80-83 ELSEWHERE. IF A LITTLE SUN COULD PEEK THROUGH ACROSS COASTAL SOUTH CAROLINA SOME MID 80S COULD BE REALIZED BEFORE SHOWERS DEVELOP AND KNOCK TEMPS BACK DOWN. PRECIPITATION SHOULD GRADUALLY END OVERNIGHT BEHIND THE SURFACE LOW AS IT CRAWLS NORTHEASTWARD ALONG THE FRONT. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...FRONTAL LOW WILL BE CROSSING THE REGION ON TUESDAY. THERE IS STILL SOME MINOR TIMING DIFFERENCES BU THE SLIGHTLY QUICKER WRF SEEMS TO FIT BEST WITH PREVIOUS THINKING. AFTER WHAT SHOULD STILL BE A RATHER WET START RAIN CHANCES AND MOREOVER RAINFALL AMOUNTS WILL BE ON THE WANE BY AFTERNOON AS MID LEVEL DRYING IN ZONAL FLOW INCREASINGLY OFFSETS THE LINGERING LL FRONTAL MOISTURE. AS THIS DRYING TREND CONTINUES DOWN INTO THE LOWER LEVELS TUESDAY NIGHT INTO WEDNESDAY TI WILL NOT ONLY LEAD TO A FURTHER DECREASE IN RAIN CHANCES (TO NEAR ZERO) BUT ALSO TAKE ON THE FORM OF DECREASING CLOUD COVER. TEMPS TUESDAY WILL HAVE A COASTAL VS INLAND RANGE AS THE LATTER MAY SEE SOME BREAKS OF SUN THAT ADD A FEW DEGREES OF WARMTH. ON WEDNESDAY A WEAK SFC GRADIENT PAIRED WITH SOME SUBTLE HEIGHT RISES ALOFT SHOULD YIELD SEASONABLE TO SLIGHTLY WARM TEMPERATURES. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY...WARM WEATHER EXPECTED THURSDAY AND FRIDAY WITH A GRADUAL INCREASE IN RAIN CHANCES STARTING THURSDAY NIGHT AS A COLD FRONT APPROACHES. THE GFS HAS MADE A CONSIDERABLE SHIFT TOWARDS QUICKER TIMING WITH THIS BOUNDARY THAT COULD IMPLY THAT FRIDAY IS IN FACT NOT THAT MILD ANYMORE. POSSIBLE...BUT TOO NEW AN IDEA TO LATCH ONTO AT THIS POINT. INTERESTINGLY THE 00Z ECMWF IS SLOWER THAN NOT ONLY PREV MODEL BUT PREV THINKING. BEST GUESS IS THAT HIGHEST POPS SHOULD COME FRIDAY NIGHT. TEMPERATURES WILL ALSO BE HIGHLY MODULATED BY THE TIMING OF FROPA AS IT MAY BE PACKING SOME CONSIDERABLY COOLER AIR. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 18Z...AT KFLO/KLBT IFR/TEMPO LIFR WILL CONTINUE AT LEAST INTO THE EARLY EVENING HOURS. GRADUAL IMPROVEMENT IN VSBYS EXPECTED THIS AFTERNOON AS RA ENDS FROM W-E AND WINDS BECOME N. AT THE COASTAL TERMINALS VFR/TEMPO MVFR EXPECTED WITH PREDOMINATE SHRA. ISOLATED TSRA POSSIBLE BUT WILL NOT INCLUDE IN TAFS ATTM. DUE TO QUICK MOVEMENT OF ISOLATED HEAVIER SHRA BRIEF PERIODS OF IFR POSSIBLE AT COASTAL TERMINALS. AT THE COASTAL TERMINALS WINDS WILL BE S-SW AND GUSTY...EXCEPT LIGHT SE AT KILM. PRECIPITATION ENDS COASTAL TERMINALS THIS EVENING. IFR WILL IMPROVE TO MVFR KFLO/KLBT OVERNIGHT AS WEAK HIGH PRESSURE/SUBSIDENCE BUILDS IN. SOME IFR POSSIBLE COASTAL TERMINALS OVERNIGHT. SUB-VFR CONDITIONS IMPROVE TO VFR MID MORNING AT KFLO/KLBT AND COASTAL TERMINALS LATE IN THE TAF VALID PERIOD AS WINDS BECOME WESTERLY. EXTENDED OUTLOOK...CHANCE OF SHOWERS EARLY TUESDAY. OTHERWISE VFR WILL DEVELOP TUESDAY AND PERSIST THROUGH THURSDAY. SHOWERS/TSTMS RETURN ON FRIDAY AS ANOTHER COLD FRONT APPROACHES THE TERMINALS. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 100 PM MONDAY...QUITE A BELT OF STRONG SOUTHERLY WINDS HAS DEVELOPED ALONG THE SOUTH CAROLINA COAST IN THE PAST FEW HOURS. MESOANALYSIS SHOWS THIS IS A TIGHTENING OF THE PRESSURE GRADIENT OUT AHEAD OF THE LOW WHICH IS NOW CENTERED JUST SOUTHWEST OF FLORENCE SC. SOUTH WINDS 15-20 KNOTS WITH 25 KNOT GUSTS SHOULD CONTINUE THROUGH THE AFTERNOON...SPREADING NORTHWARD WITH TIME TO INCLUDE THE BRUNSWICK COUNTY COASTLINE AS FAR EAST AS CAPE FEAR...THEN SPREADING NORTH AND EAST OF CAPE FEAR THIS EVENING. FORTUNATELY INLAND AIR TEMPERATURES ARE NO WARMER THAN OFFSHORE SO THERE IS NO SEABREEZE COMPONENT TO ADD TO WIND SPEEDS. WAVES OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO WHIP NORTHWARD ACROSS THE AREA INTO THE EVENING. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...THE START OF THE PERIOD WILL BE THE MOST ACTIVE AS LOW PRESSURE MOVES UP FRONTAL BOUNDARY JUST INLAND FROM THE COAST. THIS WILL TIGHTEN THE GRADIENT TO THE POINT WHERE WINDS SHOULD BE IN THE 15 TO 20 KT RANGE MOST AREAS...ALTHOUGH WIND SPEEDS MAY ALREADY BE FALLING OVER SOUTHERN ZONES. SOME 5 FT SEAS MAY BE AFFECTING WATERS ALONG FRYING PAN SHOALS BUT ENOUGH OF A NEARSHORE/OFFSHORE GRADIENT EXPECTED TO PRECLUDE CAUTIONARY HEADLINES. THE EXIT OF THE WAVE WILL LEAD TO FAIRLY RAPID DECREASE IN WINDS AND SEAS LATE TUESDAY INTO TUESDAY NIGHT FROM SOUTH TO NORTH. AS WIND SPEEDS DECREASE THERE WILL ALSO BE VEERING IN DIRECTION AND THE EXITING WAVE PUSHES THE FRONT OFFSHORE. A LIGHT NORTHERLY WIND IS THUS EXPECTED ON WEDNESDAY AT LEAST TO START THE DAY. A TURN TO A MORE ONSHORE DIRECTION WILL AT FIRST BE LOCALIZED AS THE SEA BREEZE KICKS IN BUT THEN SHOULD OCCUR GENTLY AREA-WIDE AS THE SYNOPTIC SCALE FLOW TURNS TO WEAKLY SOUTHERLY. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 300 AM MONDAY...JUST A GENTLE SW FLOW DEVELOPING ON THURSDAY AS THE NORMAL WEST ATLANTIC HIGH PRESSURE HAS TROUBLE GETTING ESTABLISHED INTO THE SOUTHEAST AND MID ATLANTIC BY SOME LINGER TROUGHINESS. THIS FLOW REGIME WILL STRENGTHEN ON FRIDAY AS A FAIRLY STRONG COLD FRONT APPROACHES. MODELS HAVE DIVERGED OVERNIGHT WITH THE TIMING OF THIS FRONT SO THE DEGREE OF STRENGTHENING HAS COME INTO QUESTION. && .TIDES/COASTAL FLOODING... AS OF 600 AM MONDAY...THE LOWER CAPE FEAR RIVER IS EXPECTED TO EXCEED MINOR COASTAL FLOOD THRESHOLDS DURING HIGH TIDE THIS MORNING AND A COASTAL FLOOD ADVISORY HAS BEEN ISSUED. THE EVENING HIGH TIDE WILL BE THE HIGHER OF THE TWO HIGH TIDES AND WE EXPECT WATER LEVELS WILL BE EVEN HIGHER LATE THIS EVENING. HIGH TIDE IN DOWNTOWN WILMINGTON IS AT 930 AM AND 10 PM. THE RISK FOR MINOR COASTAL FLOODING ALONG PORTIONS OF THE LOWER CAPE FEAR RIVER DURING HIGH TIDE WILL CONTINUE FOR MUCH OF THE WEEK. THE FULL MOON IS TODAY. THE LATE NIGHT TIDE WILL BE HIGHEST. THE FULL MOON MAY EXACERBATE ANY FLOOD ISSUES ALONG THE COAST THIS MORNING AND AGAIN THIS EVE. HIGH TIDE AT THE BEACHES IS AROUND 7 AM AND 730 PM. HOWEVER...WE DO NOT EXPECT MINOR COASTAL FLOOD THRESHOLDS TO BE REACHED AT THE BEACHES. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...FLOOD WATCH THROUGH THIS EVENING FOR SCZ017-023-024. NC...FLOOD WATCH THROUGH THIS EVENING FOR NCZ087. FLOOD WATCH THROUGH TUESDAY MORNING FOR NCZ096-099-105>110. COASTAL FLOOD ADVISORY UNTIL 11 AM EDT THIS MORNING FOR NCZ107. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...MBB LONG TERM...MBB AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
604 AM EDT MON SEP 8 2014 .SYNOPSIS... WET WEATHER IS EXPECTED TODAY AS LOW PRESSURE DRAGS TROPICAL MOISTURE UP ALONG A FRONT THAT HAS STALLED OVER THE EASTERN CAROLINAS. DRIER AIR BUILDING IN TUESDAY WILL ALLOW FOR A WARMING TREND WEDNESDAY AND THURSDAY. A FAIRLY ROBUST COLD FRONT MAY ARRIVE FRIDAY NIGHT OR SATURDAY. THE COLD FRONT WILL MOVE OFF THE COAST SATURDAY NIGHT WITH HIGH PRESSURE BUILDING IN FROM THE NORTH FOR SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 600 AM MONDAY...MAIN CONCERN AGAIN IS THE POTENTIAL FOR EXCESSIVE RAINFALL THROUGH TONIGHT. WEAK LOW PRESSURE WILL SLOWLY MOVE UP ALONG A STALLED FRONT ACROSS THE EASTERN CAROLINAS. ALTHOUGH TIMING DIFFERENCES REMAIN...LOW PRESSURE SHOULD BE MOVING NORTH OF THE FORECAST AREA TUE MORNING. A FRONT LIES FROM ABOUT ILM TO HYW TO CKI THIS MORNING AND IS EXPECTED TO MOVE LITTLE AND MAY EVEN RETROGRADE SLIGHTLY AS WEAK LOW PRESSURE MOVES UP ALONG THE BOUNDARY. PRECIPITABLE WATER VALUES REMAIN NEAR THE 99TH PERCENTILE AND UP TO 2.4 INCHES. TROPICAL MOISTURE WILL CONTINUE TO STREAM NORTHWARD ALONG AND AHEAD OF THE FRONT AND WILL BE LIFTED UP AND OVER THE FRONT WITH GOOD OVERRUNNING BACK ACROSS EVEN OUR MOST INLAND COUNTIES. THUS...WE ARE EXPECTING AVERAGE RAINFALL AMOUNTS ACROSS THE FORECAST AREA OF 1 TO 3 INCHES. HOWEVER...THE POTENTIAL IS THERE FOR TWICE THESE VALUES WHERE CONVECTION REPEATEDLY MOVES ACROSS THE SAME GENERAL AREA. FLOOD GUIDANCE HAS COME DOWN SLIGHTLY SINCE SUNDAY OWING TO THE GOOD RAINFALL AMOUNTS WHICH FELL ACROSS MOST OF THE AREA. THE HEAVIEST RAINFALL SHOULD OCCUR TODAY INTO THIS EVE...BUT MAY LINGER FOR MUCH OF THE NIGHT ALONG THE COAST... ESPECIALLY THE CAPE FEAR AREA. WILL SHOW POPS DIMINISHING IN THE WAKE OF LOW PRESSURE. THE FLOOD THREAT WHILE REAL...LOOKS TO STILL BE RATHER LOCALIZED AND THE CONSENSUS AMONG ALL NEARBY NWS OFFICES AND THE NATIONAL CENTER IS TO FORGO A FLOOD WATCH AT THIS TIME. HOWEVER...WE DO EXPECT SEVERAL FLOOD ADVISORIES WILL BE ISSUED THROUGH TONIGHT WITH THE FLOOD RISK GREATEST IN URBANIZED AREAS WHERE DRAINAGE IS POOR. THICK CLOUDS AND PRECIPITATION WILL GREATLY REDUCE THE DIURNAL RANGE AND WE ARE ONLY EXPECTING HIGHS TO REACH THE LOWER 80S WITH SOME OF OUR NORTHERN MOST COMMUNITIES PERHAPS FALLING JUST SHORT OF 80 DEGREES. TONIGHT...LOWS WILL BE IN THE UPPER 60S TO LOWER 70S...COOLEST ALONG AND WEST OF INTERSTATE 95. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... AS OF 300 AM MONDAY...FRONTAL LOW WILL BE CROSSING THE REGION ON TUESDAY. THERE IS STILL SOME MINOR TIMING DIFFERENCES BU THE SLIGHTLY QUICKER WRF SEEMS TO FIT BEST WITH PREVIOUS THINKING. AFTER WHAT SHOULD STILL BE A RATHER WET START RAIN CHANCES AND MOREOVER RAINFALL AMOUNTS WILL BE ON THE WANE BY AFTERNOON AS MID LEVEL DRYING IN ZONAL FLOW INCREASINGLY OFFSETS THE LINGERING LL FRONTAL MOISTURE. AS THIS DRYING TREND CONTINUES DOWN INTO THE LOWER LEVELS TUESDAY NIGHT INTO WEDNESDAY TI WILL NOT ONLY LEAD TO A FURTHER DECREASE IN RAIN CHANCES (TO NEAR ZERO) BUT ALSO TAKE ON THE FORM OF DECREASING CLOUD COVER. TEMPS TUESDAY WILL HAVE A COASTAL VS INLAND RANGE AS THE LATTER MAY SEE SOME BREAKS OF SUN THAT ADD A FEW DEGREES OF WARMTH. ON WEDNESDAY A WEAK SFC GRADIENT PAIRED WITH SOME SUBTLE HEIGHT RISES ALOFT SHOULD YIELD SEASONABLE TO SLIGHTLY WARM TEMPERATURES. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY...WARM WEATHER EXPECTED THURSDAY AND FRIDAY WITH A GRADUAL INCREASE IN RAIN CHANCES STARTING THURSDAY NIGHT AS A COLD FRONT APPROACHES. THE GFS HAS MADE A CONSIDERABLE SHIFT TOWARDS QUICKER TIMING WITH THIS BOUNDARY THAT COULD IMPLY THAT FRIDAY IS IN FACT NOT THAT MILD ANYMORE. POSSIBLE...BUT TOO NEW AN IDEA TO LATCH ONTO AT THIS POINT. INTERESTINGLY THE 00Z ECMWF IS SLOWER THAN NOT ONLY PREV MODEL BUT PREV THINKING. BEST GUESS IS THAT HIGHEST POPS SHOULD COME FRIDAY NIGHT. TEMPERATURES WILL ALSO BE HIGHLY MODULATED BY THE TIMING OF FROPA AS IT MAY BE PACKING SOME CONSIDERABLY COOLER AIR. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...UNSETTLED WEATHER WILL PERSIST THROUGH THE PERIOD AS A SURFACE LOW SLOWLY MOVES UP THE COAST AND MERGES WITH A STALLING COLD FRONT OVER THE EASTERN CAROLINAS. THE LATEST HRRR RUNS DEPICT SHRA/TSRA INCREASING IN COVERAGE THIS MORNING. THE HEAVIEST ACTIVITY IS EXPECTED ALONG THE COAST...WHERE DOWNPOURS COULD BRIEFLY REDUCE VSBYS TO MVFR/IFR LEVELS. POST-FRONTAL IFR CIGS ARE ALREADY SPREADING OVER OUR INLAND ZONES...SO THE STRATUS AT KLBT/KFLO WILL LIKELY PERSIST THROUGH THE MORNING HOURS. EXPECT MAINLY MVFR CIGS AT THE COASTAL TERMS...THOUGH PERSISTENT RAINFALL COULD LOWER CIGS BELOW 1KFT AT TIMES. EXPECT MORE WIDESPREAD SHOWERS/ISO TSTMS DURING THE DAY AS THE LOW MOVES UP THE COAST. MVFR CONDITIONS ARE EXPECTED TO PREVAIL DURING THE AFTN WITH BRIEF AND LOCALIZED AREAS OF IFR. THERE IS STILL SOME UNCERTAINTY REGARDING THE SPEED AND TRACK OF THE LOW...WHICH MAKES FOR A LOWER CONFIDENCE WIND FORECAST. IT LOOKS LIKE THE COAST WILL SEE SOUTHEAST WINDS 10 KT WITH HIGHER GUSTS POSSIBLE IF THE LOW DEEPENS. MEANWHILE THE INLAND TERMS WILL KEEP NORTHEAST WINDS AOB 10 KT FOR MUCH OF THE DAY. PCPN WILL TAPER OFF FROM SW TO NE AS THE LOW CONTINUES MOVING NORTHWARD...WITH WINDS SHIFTING TO THE NORTH ON THE BACKSIDE OF THE LOW NEAR THE END OF THE PERIOD. EXTENDED OUTLOOK...CHANCE OF SHOWERS EARLY TUESDAY. OTHERWISE VFR WILL PREVAIL THROUGH THURSDAY. SHOWERS/TSTMS RETURN ON FRIDAY AS ANOTHER COLD FRONT APPROACHES OUR CWA. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 600 AM MONDAY...A SMALL CRAFT SHOULD EXERCISE CAUTION HAS BEEN ISSUED FOR TODAY FOR ALL WATERS EXCEPT THOSE NORTH OF THE MOUTH OF THE CAPE FEAR RIVER. WE DO EXPECT THAT HIGHER WINDS AND SEAS WILL SPREAD INTO THE NORTHERNMOST WATERS TONIGHT. MARINERS SHOULD EXPECT WIDESPREAD HEAVY RAIN AND POOR VISIBILITIES ACROSS THE WATERS IN TROPICAL DOWNPOURS INTO TONIGHT. LOW PRESSURE WILL MOVE UP ALONG A STALLED FRONT JUST WEST OF THE WATERS. THIS WILL TIGHTEN THE PRESSURE GRADIENT...RESULTING IN BUILDING SEAS AND INCREASING WINDS. WINDS ARE EXPECTED TO PEAK AROUND 20 KT WITH WIND SPEEDS INCREASING ACROSS THE SOUTHERN WATERS THIS MORNING AND THE NORTHERN WATERS THIS AFTERNOON AND TONIGHT. GUSTS TO AROUND 25 KT WILL BE POSSIBLE. THE DIRECTION SHOULD HOLD SOUTH TODAY...AND THEN VEER AS LOW PRESSURE MOVES NORTH OF OUR LATITUDE. SW TO W WINDS SHOULD GRADUALLY DEVELOP ACROSS THE WATERS OVERNIGHT AND TUE MORNING. AS THE DIRECTION VEERS...WIND SPEEDS WILL DIMINISH. IN RESPONSE TO THE INCREASING WINDS...SEAS WILL BUILD TO 4 TO 5 FT. IT IS POSSIBLE FOR A BRIEF PERIOD OF 6 FT SEAS. SEAS WILL BE HIGHEST ACROSS THE SOUTHERN WATERS TODAY AND THE NORTHERN WATERS TONIGHT. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...THE START OF THE PERIOD WILL BE THE MOST ACTIVE AS LOW PRESSURE MOVES UP FRONTAL BOUNDARY JUST INLAND FROM THE COAST. THIS WILL TIGHTEN THE GRADIENT TO THE POINT WHERE WINDS SHOULD BE IN THE 15 TO 20 KT RANGE MOST AREAS...ALTHOUGH WIND SPEEDS MAY ALREADY BE FALLING OVER SOUTHERN ZONES. SOME 5 FT SEAS MAY BE AFFECTING WATERS ALONG FRYING PAN SHOALS BUT ENOUGH OF A NEARSHORE/OFFSHORE GRADIENT EXPECTED TO PRECLUDE CAUTIONARY HEADLINES. THE EXIT OF THE WAVE WILL LEAD TO FAIRLY RAPID DECREASE IN WINDS AND SEAS LATE TUESDAY INTO TUESDAY NIGHT FROM SOUTH TO NORTH. AS WIND SPEEDS DECREASE THERE WILL ALSO BE VEERING IN DIRECTION AND THE EXITING WAVE PUSHES THE FRONT OFFSHORE. A LIGHT NORTHERLY WIND IS THUS EXPECTED ON WEDNESDAY AT LEAST TO START THE DAY. A TURN TO A MORE ONSHORE DIRECTION WILL AT FIRST BE LOCALIZED AS THE SEA BREEZE KICKS IN BUT THEN SHOULD OCCUR GENTLY AREA-WIDE AS THE SYNOPTIC SCALE FLOW TURNS TO WEAKLY SOUTHERLY. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 300 AM MONDAY...JUST A GENTLE SW FLOW DEVELOPING ON THURSDAY AS THE NORMAL WEST ATLANTIC HIGH PRESSURE HAS TROUBLE GETTING ESTABLISHED INTO THE SOUTHEAST AND MID ATLANTIC BY SOME LINGER TROUGINESS. THIS FLOW REGIME WILL STRENGTHEN ON FRIDAY AS A FAIRLY STRONG COLD FRONT APPROACHES. MODELS HAVE DIVERGED OVERNIGHT WITH THE TIMING OF THIS FRONT SO THE DEGREE OF STRENGTHENING HAS COME INTO QUESTION. && .TIDES/COASTAL FLOODING... AS OF 600 AM MONDAY...THE LOWER CAPE FEAR RIVER IS EXPECTED TO EXCEED MINOR COASTAL FLOOD THRESHOLDS DURING HIGH TIDE THIS MORNING AND A COASTAL FLOOD ADVISORY HAS BEEN ISSUED. THE EVENING HIGH TIDE WILL BE THE HIGHER OF THE TWO HIGH TIDES AND WE EXPECT WATER LEVELS WILL BE EVEN HIGHER LATE THIS EVENING. HIGH TIDE IN DOWNTOWN WILMINGTON IS AT 930 AM AND 10 PM. THE RISK FOR MINOR COASTAL FLOODING ALONG PORTIONS OF THE LOWER CAPE FEAR RIVER DURING HIGH TIDE WILL CONTINUE FOR MUCH OF THE WEEK. THE FULL MOON IS TODAY. THE LATE NIGHT TIDE WILL BE HIGHEST. THE FULL MOON MAY EXACERBATE ANY FLOOD ISSUES ALONG THE COAST THIS MORNING AND AGAIN THIS EVE. HIGH TIDE AT THE BEACHES IS AROUND 7 AM AND 730 PM. HOWEVER...WE DO NOT EXPECT MINOR COASTAL FLOOD THRESHOLDS TO BE REACHED AT THE BEACHES. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...COASTAL FLOOD ADVISORY UNTIL 11 AM EDT THIS MORNING FOR NCZ107. MARINE...NONE. && $$ NEAR TERM...RJD SHORT TERM...MBB LONG TERM...MBB AVIATION...RJD/BJR TIDES/COASTAL FLOODING...RJD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
341 AM EDT MON SEP 8 2014 .SYNOPSIS... WET WEATHER IS EXPECTED TODAY AS LOW PRESSURE DRAGS TROPICAL MOISTURE UP ALONG A FRONT THAT HAS STALLED OVER THE EASTERN CAROLINAS. DRIER AIR BUILDING IN TUESDAY WILL ALLOW FOR A WARMING TREND WEDNESDAY AND THURSDAY. A FAIRLY ROBUST COLD FRONT MAY ARRIVE FRIDAY NIGHT OR SATURDAY. THE COLD FRONT WILL MOVE OFF THE COAST SATURDAY NIGHT WITH HIGH PRESSURE BUILDING IN FROM THE NORTH FOR SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM MONDAY...MAIN CONCERN AGAIN IS THE POTENTIAL FOR EXCESSIVE RAINFALL THROUGH TONIGHT. WEAK LOW PRESSURE WILL SLOWLY MOVE UP ALONG A STALLED FRONT ACROSS THE EASTERN CAROLINAS. ALTHOUGH TIMING DIFFERENCES REMAIN...LOW PRESSURE SHOULD BE MOVING NORTH OF THE FORECAST AREA TUE MORNING. A FRONT LIES FROM ABOUT ILM TO HYW TO CKI THIS MORNING AND IS EXPECTED TO MOVE LITTLE AND MAY EVEN RETROGRADE SLIGHTLY AS WEAK LOW PRESSURE MOVES UP ALONG THE BOUNDARY. PRECIPITABLE WATER VALUES REMAIN NEAR THE 99TH PERCENTILE AND UP TO 2.4 INCHES. TROPICAL MOISTURE WILL CONTINUE TO STREAM NORTHWARD ALONG AND AHEAD OF THE FRONT AND WILL BE LIFTED UP AND OVER THE FRONT WITH GOOD OVERRUNNING BACK ACROSS EVEN OUR MOST INLAND COUNTIES. THUS...WE ARE EXPECTING AVERAGE RAINFALL AMOUNTS ACROSS THE FORECAST AREA OF 1 TO 3 INCHES. HOWEVER...THE POTENTIAL IS THERE FOR TWICE THESE VALUES WHERE CONVECTION REPEATEDLY MOVES ACROSS THE SAME GENERAL AREA. FLOOD GUIDANCE HAS COME DOWN SLIGHTLY SINCE SUNDAY OWING TO THE GOOD RAINFALL AMOUNTS WHICH FELL ACROSS MOST OF THE AREA. THE HEAVIEST RAINFALL SHOULD OCCUR TODAY INTO THIS EVE...BUT MAY LINGER FOR MUCH OF THE NIGHT ALONG THE COAST... ESPECIALLY THE CAPE FEAR AREA. WILL SHOW POPS DIMINISHING IN THE WAKE OF LOW PRESSURE. THE FLOOD THREAT WHILE REAL...LOOKS TO STILL BE RATHER LOCALIZED AND THE CONSENSUS AMONG ALL NEARBY NWS OFFICES AND THE NATIONAL CENTER IS TO FORGO A FLOOD WATCH AT THIS TIME. HOWEVER...WE DO EXPECT SEVERAL FLOOD ADVISORIES WILL BE ISSUED THROUGH TONIGHT WITH THE FLOOD RISK GREATEST IN URBANIZED AREAS WHERE DRAINAGE IS POOR. THE FULL MOON MAY EXACERBATE ANY FLOOD ISSUES ALONG THE COAST THIS MORNING AND AGAIN THIS EVE. HIGH TIDE AT THE BEACHES IS AROUND 7 AM AND 730 PM. HOWEVER...WE DO NOT EXPECT MINOR COASTAL FLOOD THRESHOLDS TO BE REACHED AT THE BEACHES. HOWEVER...THE LOWER CAPE FEAR RIVER WILL BE MORE PROBLEMATIC. ALTHOUGH WE SHOULD STAY JUST BELOW CRITERIA THIS MORNING...WE WILL LIKELY AGAIN EXCEED THRESHOLDS THIS EVE. HIGH TIDE IN DOWNTOWN WILMINGTON IS AT 930 AM AND 10 PM. THICK CLOUDS AND PRECIPITATION WILL GREATLY REDUCE THE DIURNAL RANGE AND WE ARE ONLY EXPECTING HIGHS TO REACH THE LOWER 80S WITH SOME OF OUR NORTHERN MOST COMMUNITIES PERHAPS FALLING JUST SHORT OF 80 DEGREES. TONIGHT...LOWS WILL BE IN THE UPPER 60S TO LOWER 70S...COOLEST ALONG AND WEST OF INTERSTATE 95. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...FRONTAL LOW WILL BE CROSSING THE REGION ON TUESDAY. THERE IS STILL SOME MINOR TIMING DIFFERENCES BU THE SLIGHTLY QUICKER WRF SEEMS TO FIT BEST WITH PREVIOUS THINKING. AFTER WHAT SHOULD STILL BE A RATHER WET START RAIN CHANCES AND MOREOVER RAINFALL AMOUNTS WILL BE ON THE WANE BY AFTERNOON AS MID LEVEL DRYING IN ZONAL FLOW INCREASINGLY OFFSETS THE LINGERING LL FRONTAL MOISTURE. AS THIS DRYING TREND CONTINUES DOWN INTO THE LOWER LEVELS TUESDAY NIGHT INTO WEDNESDAY TI WILL NOT ONLY LEAD TO A FURTHER DECREASE IN RAIN CHANCES (TO NEAR ZERO) BUT ALSO TAKE ON THE FORM OF DECREASING CLOUD COVER. TEMPS TUESDAY WILL HAVE A COASTAL VS INLAND RANGE AS THE LATTER MAY SEE SOME BREAKS OF SUN THAT ADD A FEW DEGREES OF WARMTH. ON WEDNESDAY A WEAK SFC GRADIENT PAIRED WITH SOME SUBTLE HEIGHT RISES ALOFT SHOULD YIELD SEASONABLE TO SLIGHTLY WARM TEMPERATURES. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY...WARM WEATHER EXPECTED THURSDAY AND FRIDAY WITH A GRADUAL INCREASE IN RAIN CHANCES STARTING THURSDAY NIGHT AS A COLD FRONT APPROACHES. THE GFS HAS MADE A CONSIDERABLE SHIFT TOWARDS QUICKER TIMING WITH THIS BOUNDARY THAT COULD IMPLY THAT FRIDAY IS IN FACT NOT THAT MILD ANYMORE. POSSIBLE...BUT TOO NEW AN IDEA TO LATCH ONTO AT THIS POINT. INTERESTINGLY THE 00Z ECMWF IS SLOWER THAN NOT ONLY PREV MODEL BUT PREV THINKING. BEST GUESS IS THAT HIGHEST POPS SHOULD COME FRIDAY NIGHT. TEMPERATURES WILL ALSO BE HIGHLY MODULATED BY THE TIMING OF FROPA AS IT MAY BE PACKING SOME CONSIDERABLY COOLER AIR. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...UNSETTLED WEATHER WILL PERSIST THROUGH THE PERIOD AS A SURFACE LOW SLOWLY MOVES UP THE COAST AND MERGES WITH A STALLING COLD FRONT OVER THE EASTERN CAROLINAS. THE LATEST HRRR RUNS DEPICT SHRA/TSRA INCREASING IN COVERAGE THIS MORNING. THE HEAVIEST ACTIVITY IS EXPECTED ALONG THE COAST...WHERE DOWNPOURS COULD BRIEFLY REDUCE VSBYS TO MVFR/IFR LEVELS. POST-FRONTAL IFR CIGS ARE ALREADY SPREADING OVER OUR INLAND ZONES...SO THE STRATUS AT KLBT/KFLO WILL LIKELY PERSIST THROUGH THE MORNING HOURS. EXPECT MAINLY MVFR CIGS AT THE COASTAL TERMS...THOUGH PERSISTENT RAINFALL COULD LOWER CIGS BELOW 1KFT AT TIMES. EXPECT MORE WIDESPREAD SHOWERS/ISO TSTMS DURING THE DAY AS THE LOW MOVES UP THE COAST. MVFR CONDITIONS ARE EXPECTED TO PREVAIL DURING THE AFTN WITH BRIEF AND LOCALIZED AREAS OF IFR. THERE IS STILL SOME UNCERTAINTY REGARDING THE SPEED AND TRACK OF THE LOW...WHICH MAKES FOR A LOWER CONFIDENCE WIND FORECAST. IT LOOKS LIKE THE COAST WILL SEE SOUTHEAST WINDS 10 KT WITH HIGHER GUSTS POSSIBLE IF THE LOW DEEPENS. MEANWHILE THE INLAND TERMS WILL KEEP NORTHEAST WINDS AOB 10 KT FOR MUCH OF THE DAY. PCPN WILL TAPER OFF FROM SW TO NE AS THE LOW CONTINUES MOVING NORTHWARD...WITH WINDS SHIFTING TO THE NORTH ON THE BACKSIDE OF THE LOW NEAR THE END OF THE PERIOD. EXTENDED OUTLOOK...CHANCE OF SHOWERS EARLY TUESDAY. OTHERWISE VFR WILL PREVAIL THROUGH THURSDAY. SHOWERS/TSTMS RETURN ON FRIDAY AS ANOTHER COLD FRONT APPROACHES OUR CWA. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM MONDAY...A SMALL CRAFT SHOULD EXERCISE CAUTION HAS BEEN ISSUED FOR TODAY FOR ALL WATERS EXCEPT THOSE NORTH OF THE MOUTH OF THE CAPE FEAR RIVER. WE DO EXPECT THAT HIGHER WINDS AND SEAS WILL SPREAD INTO THE NORTHERNMOST WATERS TONIGHT. MARINERS SHOULD EXPECT WIDESPREAD HEAVY RAIN AND POOR VISIBILITIES ACROSS THE WATERS IN TROPICAL DOWNPOURS INTO TONIGHT. LOW PRESSURE WILL MOVE UP ALONG A STALLED FRONT JUST WEST OF THE WATERS. THIS WILL TIGHTEN THE PRESSURE GRADIENT...RESULTING IN BUILDING SEAS AND INCREASING WINDS. WINDS ARE EXPECTED TO PEAK AROUND 20 KT WITH WIND SPEEDS INCREASING ACROSS THE SOUTHERN WATERS THIS MORNING AND THE NORTHERN WATERS THIS AFTERNOON AND TONIGHT. GUSTS TO AROUND 25 KT WILL BE POSSIBLE. THE DIRECTION SHOULD HOLD SOUTH TODAY...AND THEN VEER AS LOW PRESSURE MOVES NORTH OF OUR LATITUDE. SW TO W WINDS SHOULD GRADUALLY DEVELOP ACROSS THE WATERS OVERNIGHT AND TUE MORNING. AS THE DIRECTION VEERS...WIND SPEEDS WILL DIMINISH. IN RESPONSE TO THE INCREASING WINDS...SEAS WILL BUILD TO 4 TO 5 FT. IT IS POSSIBLE FOR A BRIEF PERIOD OF 6 FT SEAS. SEAS WILL BE HIGHEST ACROSS THE SOUTHERN WATERS TODAY AND THE NORTHERN WATERS TONIGHT. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...THE START OF THE PERIOD WILL BE THE MOST ACTIVE AS LOW PRESSURE MOVES UP FRONTAL BOUNDARY JUST INLAND FROM THE COAST. THIS WILL TIGHTEN THE GRADIENT TO THE POINT WHERE WINDS SHOULD BE IN THE 15 TO 20 KT RANGE MOST AREAS...ALTHOUGH WIND SPEEDS MAY ALREADY BE FALLING OVER SOUTHERN ZONES. SOME 5 FT SEAS MAY BE AFFECTING WATERS ALONG FRYING PAN SHOALS BUT ENOUGH OF A NEARSHORE/OFFSHORE GRADIENT EXPECTED TO PRECLUDE CAUTIONARY HEADLINES. THE EXIT OF THE WAVE WILL LEAD TO FAIRLY RAPID DECREASE IN WINDS AND SEAS LATE TUESDAY INTO TUESDAY NIGHT FROM SOUTH TO NORTH. AS WIND SPEEDS DECREASE THERE WILL ALSO BE VEERING IN DIRECTION AND THE EXITING WAVE PUSHES THE FRONT OFFSHORE. A LIGHT NORTHERLY WIND IS THUS EXPECTED ON WEDNESDAY AT LEAST TO START THE DAY. A TURN TO A MORE ONSHORE DIRECTION WILL AT FIRST BE LOCALIZED AS THE SEA BREEZE KICKS IN BUT THEN SHOULD OCCUR GENTLY AREA-WIDE AS THE SYNOPTIC SCALE FLOW TURNS TO WEAKLY SOUTHERLY. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 300 AM MONDAY...JUST A GENTLE SW FLOW DEVELOPING ON THURSDAY AS THE NORMAL WEST ATLANTIC HIGH PRESSURE HAS TROUBLE GETTING ESTABLISHED INTO THE SOUTHEAST AND MID ATLANTIC BY SOME LINGER TROUGINESS. THIS FLOW REGIME WILL STRENGTHEN ON FRIDAY AS A FAIRLY STRONG COLD FRONT APPROACHES. MODELS HAVE DIVERGED OVERNIGHT WITH THE TIMING OF THIS FRONT SO THE DEGREE OF STRENGTHENING HAS COME INTO QUESTION. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...RJD SHORT TERM...MBB LONG TERM...MBB AVIATION...BJR/RJD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
330 AM EDT MON SEP 8 2014 .SYNOPSIS... WET WEATHER IS EXPECTED TODAY AS LOW PRESSURE DRAGS TROPICAL MOISTURE UP ALONG A FRONT THAT HAS STALLED OVER THE EASTERN CAROLINAS. DRIER AIR BUILDING IN TUESDAY WILL ALLOW FOR A WARMING TREND WEDNESDAY AND THURSDAY. A FAIRLY ROBUST COLD FRONT MAY ARRIVE FRIDAY NIGHT OR SATURDAY. THE COLD FRONT WILL MOVE OFF THE COAST SATURDAY NIGHT WITH HIGH PRESSURE BUILDING IN FROM THE NORTH FOR SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM MONDAY...MAIN CONCERN AGAIN IS THE POTENTIAL FOR EXCESSIVE RAINFALL THROUGH TONIGHT. WEAK LOW PRESSURE WILL SLOWLY MOVE UP ALONG A STALLED FRONT ACROSS THE EASTERN CAROLINAS. ALTHOUGH TIMING DIFFERENCES REMAIN...LOW PRESSURE SHOULD BE MOVING NORTH OF THE FORECAST AREA TUE MORNING. A FRONT LIES FROM ABOUT ILM TO HYW TO CKI THIS MORNING AND IS EXPECTED TO MOVE LITTLE AND MAY EVEN RETROGRADE SLIGHTLY AS WEAK LOW PRESSURE MOVES UP ALONG THE BOUNDARY. PRECIPITABLE WATER VALUES REMAIN NEAR THE 99TH PERCENTILE AND UP TO 2.4 INCHES. TROPICAL MOISTURE WILL CONTINUE TO STREAM NORTHWARD ALONG AND AHEAD OF THE FRONT AND WILL BE LIFTED UP AND OVER THE FRONT WITH GOOD OVERRUNNING BACK ACROSS EVEN OUR MOST INLAND COUNTIES. THUS...WE ARE EXPECTING AVERAGE RAINFALL AMOUNTS ACROSS THE FORECAST AREA OF 1 TO 3 INCHES. HOWEVER...THE POTENTIAL IS THERE FOR TWICE THESE VALUES WHERE CONVECTION REPEATEDLY MOVES ACROSS THE SAME GENERAL AREA. FLOOD GUIDANCE HAS COME DOWN SLIGHTLY SINCE SUNDAY OWING TO THE GOOD RAINFALL AMOUNTS WHICH FELL ACROSS MOST OF THE AREA. THE HEAVIEST RAINFALL SHOULD OCCUR TODAY INTO THIS EVE...BUT MAY LINGER FOR MUCH OF THE NIGHT ALONG THE COAST... ESPECIALLY THE CAPE FEAR AREA. WILL SHOW POPS DIMINISHING IN THE WAKE OF LOW PRESSURE. THE FLOOD THREAT WHILE REAL...LOOKS TO STILL BE RATHER LOCALIZED AND THE CONSENSUS AMONG ALL NEARBY NWS OFFICES AND THE NATIONAL CENTER IS TO FORGO A FLOOD WATCH AT THIS TIME. HOWEVER...WE DO EXPECT SEVERAL FLOOD ADVISORIES WILL BE ISSUED THROUGH TONIGHT WITH THE FLOOD RISK GREATEST IN URBANIZED AREAS WHERE DRAINAGE IS POOR. THE FULL MOON MAY EXACERBATE ANY FLOOD ISSUES ALONG THE COAST THIS MORNING AND AGAIN THIS EVE. HIGH TIDE AT THE BEACHES IS AROUND 7 AM AND 730 PM. HOWEVER...WE DO NOT EXPECT MINOR COASTAL FLOOD THRESHOLDS TO BE REACHED AT THE BEACHES. HOWEVER...THE LOWER CAPE FEAR RIVER WILL BE MORE PROBLEMATIC. ALTHOUGH WE SHOULD STAY JUST BELOW CRITERIA THIS MORNING...WE WILL LIKELY AGAIN EXCEED THRESHOLDS THIS EVE. HIGH TIDE IN DOWNTOWN WILMINGTON IS AT 930 AM AND 10 PM. THICK CLOUDS AND PRECIPITATION WILL GREATLY REDUCE THE DIURNAL RANGE AND WE ARE ONLY EXPECTING HIGHS TO REACH THE LOWER 80S WITH SOME OF OUR NORTHERN MOST COMMUNITIES PERHAPS FALLING JUST SHORT OF 80 DEGREES. TONIGHT...LOWS WILL BE IN THE UPPER 60S TO LOWER 70S...COOLEST ALONG AND WEST OF INTERSTATE 95. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 3 AM MONDAY...FRONTAL LOW WILL BE CROSSING THE REGION ON TUESDAY. THERE IS STILL SOME MINOR TIMING DIFFERENCES BU THE SLIGHTLY QUICKER WRF SEEMS TO FIT BEST WITH PREVIOUS THINKING. AFTER WHAT SHOULD STILL BE A RATHER WET START RAIN CHANCES AND MOREOVER RAINFALL AMOUNTS WILL BE ON THE WANE BY AFTERNOON AS MID LEVEL DRYING IN ZONAL FLOW INCREASINGLY OFFSETS THE LINGERING LL FRONTAL MOISTURE. AS THIS DRYING TREND CONTINUES DOWN INTO THE LOWER LEVELS TUESDAY NIGHT INTO WEDNESDAY TI WILL NOT ONLY LEAD TO A FURTHER DECREASE IN RAIN CHANCES (TO NEAR ZERO) BUT ALSO TAKE ON THE FORM OF DECREASING CLOUD COVER. TEMPS TUESDAY WILL HAVE A COASTAL VS INLAND RANGE AS THE LATTER MAY SEE SOME BREAKS OF SUN THAT ADD A FEW DEGREES OF WARMTH. ON WEDNESDAY A WEAK SFC GRADIENT PAIRED WITH SOME SUBTLE HEIGHT RISES ALOFT SHOULD YIELD SEASONABLE TO SLIGHTLY WARM TEMPERATURES. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 3 AM MONDAY...WARM WEATHER EXPECTED THURSDAY AND FRIDAY WITH A GRADUAL INCREASE IN RAIN CHANCES STARTING THURSDAY NIGHT AS A COLD FRONT APPROACHES. THE GFS HAS MADE A CONSIDERABLE SHIFT TOWARDS QUICKER TIMING WITH THIS BOUNDARY THAT COULD IMPLY THAT FRIDAY IS IN FACT NOT THAT MILD ANYMORE. POSSIBLE...BUT TOO NEW AN IDEA TO LATCH ONTO AT THIS POINT. INTERESTINGLY THE 00Z ECMWF IS SLOWER THAN NOT ONLY PREV MODEL BUT PREV THINKING. BEST GUESS IS THAT HIGHEST POPS SHOULD COME FRIDAY NIGHT. TEMPERATURES WILL ALSO BE HIGHLY MODULATED BY THE TIMING OF FROPA AS IT MAY BE PACKING SOME CONSIDERABLY COOLER AIR. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...UNSETTLED WEATHER WILL PERSIST THROUGH THE PERIOD AS A SURFACE LOW SLOWLY MOVES UP THE COAST AND MERGES WITH A STALLING COLD FRONT OVER THE EASTERN CAROLINAS. THE LATEST HRRR RUNS DEPICT SHRA/TSRA INCREASING IN COVERAGE THIS MORNING. THE HEAVIEST ACTIVITY IS EXPECTED ALONG THE COAST...WHERE DOWNPOURS COULD BRIEFLY REDUCE VSBYS TO MVFR/IFR LEVELS. POST-FRONTAL IFR CIGS ARE ALREADY SPREADING OVER OUR INLAND ZONES...SO THE STRATUS AT KLBT/KFLO WILL LIKELY PERSIST THROUGH THE MORNING HOURS. EXPECT MAINLY MVFR CIGS AT THE COASTAL TERMS...THOUGH PERSISTENT RAINFALL COULD LOWER CIGS BELOW 1KFT AT TIMES. EXPECT MORE WIDESPREAD SHOWERS/ISO TSTMS DURING THE DAY AS THE LOW MOVES UP THE COAST. MVFR CONDITIONS ARE EXPECTED TO PREVAIL DURING THE AFTN WITH BRIEF AND LOCALIZED AREAS OF IFR. THERE IS STILL SOME UNCERTAINTY REGARDING THE SPEED AND TRACK OF THE LOW...WHICH MAKES FOR A LOWER CONFIDENCE WIND FORECAST. IT LOOKS LIKE THE COAST WILL SEE SOUTHEAST WINDS 10 KT WITH HIGHER GUSTS POSSIBLE IF THE LOW DEEPENS. MEANWHILE THE INLAND TERMS WILL KEEP NORTHEAST WINDS AOB 10 KT FOR MUCH OF THE DAY. PCPN WILL TAPER OFF FROM SW TO NE AS THE LOW CONTINUES MOVING NORTHWARD...WITH WINDS SHIFTING TO THE NORTH ON THE BACKSIDE OF THE LOW NEAR THE END OF THE PERIOD. EXTENDED OUTLOOK...CHANCE OF SHOWERS EARLY TUESDAY. OTHERWISE VFR WILL PREVAIL THROUGH THURSDAY. SHOWERS/TSTMS RETURN ON FRIDAY AS ANOTHER COLD FRONT APPROACHES OUR CWA. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1100 PM SUNDAY...UPDATED WINDS DUE TO THE POSITIONING OF THE FRONTAL BOUNDARY JUST INLAND FROM THE COAST. LATEST OBS AND HRRR TRENDS INDICATE ESE-SSE DIRECTIONS ACROSS THE ILM WATERS DUE TO THE MEANDERING OF THIS FRONT. PORTIONS OF IT MAY COME WITHIN 15 MILES OR LESS FROM THE IMMEDIATE COAST AT TIMES BUT MODELS REMAIN ADAMANT IN KEEPING IT INLAND. SIGNIFICANT SEAS REMAIN 2 TO 4 FT WITH WIND WAVES DOMINATING THE SEAS SPECTRUM...IE. DOMINANT PERIODS AROUND 5 SECONDS. SHORT TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 3 AM MONDAY...THE START OF THE PERIOD WILL BE THE MOST ACTIVE AS LOW PRESSURE MOVES UP FRONTAL BOUNDARY JUST INLAND FROM THE COAST. THIS WILL TIGHTEN THE GRADIENT TO THE POINT WHERE WINDS SHOULD BE IN THE 15 TO 20 KT RANGE MOST AREAS...ALTHOUGH WIND SPEEDS MAY ALREADY BE FALLING OVER SOUTHERN ZONES. SOME 5 FT SEAS MAY BE AFFECTING WATERS ALONG FRYING PAN SHOALS BUT ENOUGH OF A NEARSHORE/OFFSHORE GRADIENT EXPECTED TO PRECLUDE CAUTIONARY HEADLINES. THE EXIT OF THE WAVE WILL LEAD TO FAIRLY RAPID DECREASE IN WINDS AND SEAS LATE TUESDAY INTO TUESDAY NIGHT FROM SOUTH TO NORTH. AS WIND SPEEDS DECREASE THERE WILL ALSO BE VEERING IN DIRECTION AND THE EXITING WAVE PUSHES THE FRONT OFFSHORE. A LIGHT NORTHERLY WIND IS THUS EXPECTED ON WEDNESDAY AT LEAST TO START THE DAY. A TURN TO A MORE ONSHORE DIRECTION WILL AT FIRST BE LOCALIZED AS THE SEA BREEZE KICKS IN BUT THEN SHOULD OCCUR GENTLY AREA-WIDE AS THE SYNOPTIC SCALE FLOW TURNS TO WEAKLY SOUTHERLY. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3 AM MONDAY...JUST A GENTLE SW FLOW DEVELOPING ON THURSDAY AS THE NORMAL WEST ATLANTIC HIGH PRESSURE HAS TROUBLE GETTING ESTABLISHED INTO THE SOUTHEAST AND MID ATLANTIC BY SOME LINGER TROUGINESS. THIS FLOW REGIME WILL STRENGTHEN ON FRIDAY AS A FAIRLY STRONG COLD FRONT APPROACHES. MODELS HAVE DIVERGED OVERNIGHT WITH THE TIMING OF THIS FRONT SO THE DEGREE OF STRENGTHENING HAS COME INTO QUESTION. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...DCH/TRA SHORT TERM...MBB LONG TERM...MBB AVIATION...BJR/RJD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
138 AM EDT MON SEP 8 2014 .SYNOPSIS... WET WEATHER IS EXPECTED THROUGH MONDAY AS LOW PRESSURE DRAGS TROPICAL MOISTURE UP ALONG A FRONT THAT HAS STALLED OVER THE EASTERN CAROLINAS. DRIER AIR BUILDING IN TUESDAY WILL ALLOW FOR A WARMING TREND WEDNESDAY AND THURSDAY. A FAIRLY ROBUST COLD FRONT MAY ARRIVE FRIDAY NIGHT OR SATURDAY. THE COLD FRONT WILL MOVE OFF THE COAST SATURDAY NIGHT WITH HIGH PRESSURE BUILDING IN FROM THE NORTH FOR SUNDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 1100 PM SUNDAY...COASTAL FLOOD ADVISORY FOR ALONG THE CAPE FEAR RIVER FROM WILMINGTON TO FORT FISHER HAS EXPIRED. THE GAGE READING PEAKED AT 5.84 FT MLLW AT THIS EVENINGS HIGH TIDE AROUND 945 PM. THE READING 5.5 FT MLLW IS THE THRESHOLD USED FOR MINOR COASTAL FLOODING TO COMMENCE. THE COLD FRONT HAS BASICALLY STALLED AND IS ORIENTED NE-SW ACROSS THE EASTERN CAROLINAS...ROUGHLY 15 TO 40 MILES INLAND FROM THE IMMEDIATE COAST. THIS BOUNDARY WILL WILL PROVIDE A SOURCE OF LIFT FOR CONVECTION OVERNIGHT. THE SFC LOW AND ASSOCIATED DYNAMICS OVER COASTAL GA-SC IS MAKING SOME PROGRESS NE-WARD AND SHOULD FURTHER INCREASE ITS FORWARD SPEED BY DAYBREAK MONDAY AS IT ATTACHES TO THE STALLED BOUNDARY. WITH PWS ABOVE 2 INCHES ACROSS THE MAJORITY OF THE ILM CWA...WEAK INSTABILITY...FORCING FROM THE SFC BOUNDARY AND DYNAMICS ALOFT ASSOCIATED WITH THE SFC LOW...AND FRICTIONAL CONVERGENCE FROM ONSHORE FLOW...POPS WILL REACH CATEGORICAL FOR MUCH OF THE ILM CWA DURING THE PRE-DAWN MONDAY HRS. HIGHEST QPF ALONG THE IMMEDIATE COAST...TRAILING LOWER AS ONE PROGRESSES INLAND. HWO WILL MENTION ISOLATED FLOODING FROM THE HEAVY RAINFALL...MAINLY FROM THE I-95 CORRIDOR EAST TO THE COAST. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...WEAK LOW PRESSURE OVER THE GA/SC COAST MON MORNING WILL TRACK NORTHEAST ALONG A FRONT STALLED ACROSS THE AREA DURING THE DAY. LOW LEVEL CONVERGENCE AHEAD AND EAST OF THIS LOW WILL HAVE PLENTY OF DEEP TROPICAL MOISTURE TO TAP INTO. PRECIPITABLE WATER VALUES LATER MON TOP OUT AROUND 2.35 INCHES WHICH IS RIGHT AROUND THE 99TH PERCENTILE FOR THIS TIME OF YEAR. WIDESPREAD HEAVY RAIN IS EXPECTED ACROSS MUCH OF THE FORECAST AREA WITH ADDITIONAL ENHANCEMENT AHEAD AND EAST OF THE LOW THANKS TO LIFT. EAST OF THE LOWS TRACK SIGNIFICANT RAINFALL POTENTIAL WILL EXIST WITH RAINFALL RATES OF 2.5 INCHES PER HOUR AND HIGHER POSSIBLE. DEEP SOUTHWEST FLOW SHOULD KEEP STORM MOTION CLOSE TO 15 KT SO SLOW MOVING STORMS WILL NOT BE A CONCERN BUT TRAINING COULD LEAD TO EXCESSIVE LOCALIZED RAINFALL. GIVEN THE SO FAR SPOTTY NATURE OF CONVECTION THIS AFTERNOON...LACK OF SIGNIFICANT RAINFALL IN THE LAST WEEK OR SO...AND STORM MOTIONS GREATER THAN 10 KT DO NOT FEEL A NEED TO RAISE AN AREA WIDE FLOOD WATCH AT THIS POINT IN TIME. THE LOW SHOULD TRACK JUST INLAND OF THE COAST MON INTO MON NIGHT PLACING COASTAL COUNTIES IN THE AREA FAVORED FOR HEAVIEST RAIN. AREAS WEST OF THE LOW WILL STILL HAVE POTENTIAL FOR PERIODS OF HEAVY RAIN BUT COVERAGE WILL BE A LITTLE LESS GIVEN THE SLIGHTLY LESS FAVORABLE CONDITIONS...LIMITED CONVERGENCE AND WEAKER UPWARD MOTION. THE SURFACE LOW WILL START TO STRENGTHEN TUE AS IT LIFTS NORTHEAST. THIS WILL HELP PUSH THE COLD FRONT OFF THE COAST AND USHER IN DRIER AIR ALOFT. MID LEVEL RIDGE OVER THE SOUTHERN CONUS STARTS TO EXPAND EAST AS THE PERIOD ENDS. LOW LEVEL MOISTURE TENDS TO LINGER BEHIND FRONTS IN THESE SETUPS AND TUE MAY END UP ON THE CLOUDY SIDE...ESPECIALLY ALONG THE NC COAST...WITH MOISTURE TRAPPED UNDER THE BUILDING MID LEVEL RIDGE. TEMPERATURES WILL RANGE FROM NEAR TO BELOW CLIMO. HIGHS WEST OF THE LOW WILL END UP BELOW CLIMO MON BUT NEAR TO SLIGHTLY ABOVE CLIMO TUE. ALONG THE COAST THE OPPOSITE WILL BE TRUE WITH HIGHS AROUND CLIMO MON BUT NEAR TO SLIGHTLY BELOW CLIMO TUE OWING TO LINGERING LOW CLOUD AND NORTHERLY FLOW. LOWS WILL REMAIN ABOVE CLIMO BOTH NIGHTS WITH CLOUD COVER IN PLACE MON NIGHT AND MIXING/LINGERING CLOUDS TUE NIGHT. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 PM SUNDAY...WEAK HIGH PRESSURE WILL REMAIN AT THE SURFACE WHILE RIDGE IN THE MID TO UPPER LEVELS EASES BACK UP INTO THE CAROLINAS THROUGH MID WEEK WITH PLENTY OF DRY AIR AND SUBSIDENCE ALOFT. MAY INCLUDE A VERY LOW END CHC OF SHWRS BY EARLY THURS BUT OVERALL EXPECT PLENTY OF SUNSHINE WITH SOME LOCALIZED CU DEVELOPMENT AND POSSIBLY A STRAY SHWR. BY LATE THURS INTO FRI CHC OF PCP WILL INCREASE AS RIDGE ALOFT GETS SUPPRESSED FARTHER SOUTH AS A SHORTWAVE BEGINS TO DIG DOWN AS IT RIDES ACROSS THE GREAT LAKES. THIS SHORTWAVE WILL PUSH A COLD FRONT INTO THE CAROLINAS BY FRI INTO SATURDAY WITH MORE WIDESPREAD SHWR AND TSTMS EXPECTED HEADING INTO THE WEEKEND. AS THE SHORTWAVE LIFTS NORTHEAST A BROAD TROUGH WILL REMAIN OVER THE EASTERN CONUS. THEREFORE THE FRONT MAY BE SLOWER TO MOVE OFF THE COAST...BUT LATEST GFS DOES SHOW SOME DRYING BY SAT NIGHT INTO SUNDAY WITH DEWPOINT TEMPS DROPPING INTO THE 60S. PCP WATER VALUES WILL BE BELOW 1.5 INCHES ON WED BUT WILL BE UP TO 2 INCHES OR GREATER BY THURS EVENING AND WILL NOT COME BACK DOWN UNTIL SUNDAY. THE FORECAST SHOULD START OUT DRY AND END DRIER...BUT LOOKING LIKE A WET FIRST HALF OF THE WEEKEND. TEMPS WILL WARM UP AGAIN THROUGH MID WEEK IN GREATER SUNSHINE AND SLIGHT RISE IN H5 HEIGHTS AND LOW LEVEL THICKNESSES FROM WED THROUGH FRI. EXPECT TEMPS BACK UP AROUND 90 OR SO BY THURS AND FRI. BY SATURDAY CLOUDS AND SHWRS WILL AFFECT THE TEMPS AND THEN SOME COOLER AIR WILL BEGIN TO MOVE IN BEHIND FRONT LATER ON SATURDAY INTO SUNDAY...KEEPING TEMPS IN THE LOWER 80S BOTH OVER THE WEEKEND. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...UNSETTLED WEATHER WILL PERSIST THROUGH THE PERIOD AS A SURFACE LOW SLOWLY MOVES UP THE COAST AND MERGES WITH A STALLING COLD FRONT OVER THE EASTERN CAROLINAS. THE LATEST HRRR RUNS DEPICT SHRA/TSRA INCREASING IN COVERAGE THIS MORNING. THE HEAVIEST ACTIVITY IS EXPECTED ALONG THE COAST...WHERE DOWNPOURS COULD BRIEFLY REDUCE VSBYS TO MVFR/IFR LEVELS. POST-FRONTAL IFR CIGS ARE ALREADY SPREADING OVER OUR INLAND ZONES...SO THE STRATUS AT KLBT/KFLO WILL LIKELY PERSIST THROUGH THE MORNING HOURS. EXPECT MAINLY MVFR CIGS AT THE COASTAL TERMS...THOUGH PERSISTENT RAINFALL COULD LOWER CIGS BELOW 1KFT AT TIMES. EXPECT MORE WIDESPREAD SHOWERS/ISO TSTMS DURING THE DAY AS THE LOW MOVES UP THE COAST. MVFR CONDITIONS ARE EXPECTED TO PREVAIL DURING THE AFTN WITH BRIEF AND LOCALIZED AREAS OF IFR. THERE IS STILL SOME UNCERTAINTY REGARDING THE SPEED AND TRACK OF THE LOW...WHICH MAKES FOR A LOWER CONFIDENCE WIND FORECAST. IT LOOKS LIKE THE COAST WILL SEE SOUTHEAST WINDS 10 KT WITH HIGHER GUSTS POSSIBLE IF THE LOW DEEPENS. MEANWHILE THE INLAND TERMS WILL KEEP NORTHEAST WINDS AOB 10 KT FOR MUCH OF THE DAY. PCPN WILL TAPER OFF FROM SW TO NE AS THE LOW CONTINUES MOVING NORTHWARD...WITH WINDS SHIFTING TO THE NORTH ON THE BACKSIDE OF THE LOW NEAR THE END OF THE PERIOD. EXTENDED OUTLOOK...CHANCE OF SHOWERS EARLY TUESDAY. OTHERWISE VFR WILL PREVAIL THROUGH THURSDAY. SHOWERS/TSTMS RETURN ON FRIDAY AS ANOTHER COLD FRONT APPROACHES OUR CWA. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1100 PM SUNDAY...UPDATED WINDS DUE TO THE POSITIONING OF THE FRONTAL BOUNDARY JUST INLAND FROM THE COAST. LATEST OBS AND HRRR TRENDS INDICATE ESE-SSE DIRECTIONS ACROSS THE ILM WATERS DUE TO THE MEANDERING OF THIS FRONT. PORTIONS OF IT MAY COME WITHIN 15 MILES OR LESS FROM THE IMMEDIATE COAST AT TIMES BUT MODELS REMAIN ADAMANT IN KEEPING IT INLAND. SIGNIFICANT SEAS REMAIN 2 TO 4 FT WITH WIND WAVES DOMINATING THE SEAS SPECTRUM...IE. DOMINANT PERIODS AROUND 5 SECONDS. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...WEAK LOW PRESSURE MOVING NORTHEAST ALONG A FRONT STALLED JUST WEST OF THE WATERS WILL BRING ABOUT AN INCREASE IN SOUTHERLY FLOW MON. SOLID 20 KT IS LIKELY AND CANNOT RULE OUT A BRIEF PERIOD WHERE SPEEDS WILL APPROACH 25 KT...IF THE LOW IS A BIT STRONGER OR FASTER MOVING THAN CURRENTLY FORECAST. INCREASE IN WINDS WILL BUILD SEAS TO 3 TO 5 FT MON AND MON NIGHT. ALTHOUGH THERE IS POTENTIAL FOR A BRIEF PERIOD OF 6 FT...ESPECIALLY IF STRONGER SOLUTION WERE TO VERIFY...WILL KEEP SEAS CAPPED AT 5 FT FOR NOW GIVEN AMOUNT OF UNCERTAINTY. SURFACE LOW MOVES OFF TO THE NORTHEAST TUE PUSHING THE FRONT EAST OF THE WATERS AND SETTING UP OFFSHORE FLOW. EXITING LOW IS SLOW TO STRENGTHEN AND THE GRADIENT BEHIND THE BOUNDARY IS NOT VERY WELL DEFINED. OFFSHORE WINDS WILL BE AROUND 10 KT ON TUE BEFORE BACKING TO WEST-SOUTHWEST AND DROPPING BELOW 10 KT TUE NIGHT. OFFSHORE COMPONENT TO WINDS WILL KEEP SEAS 2 FT OR LESS DURING THE SECOND HALF OF THE PERIOD. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 300 PM SUNDAY...WEAK HIGH PRESSURE OVER THE WATERS WILL MAINTAIN LIGHT AND VARIABLE WINDS COMING AROUND TO THE SOUTH BY THURS BUT REMAINING 10 KTS OR LESS. BY LATE THURS INTO FRI THE S-SW WINDS WILL INCREASE UP TO 15 KTS KICKING SEAS UP A BIT. OVERALL EXPECT SEAS 3 FT OR LESS THROUGH MOST OF THE PERIOD. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...DCH/TRA SHORT TERM...III LONG TERM...RGZ AVIATION...BJR/RJD
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1236 AM EDT MON SEP 8 2014 .SYNOPSIS... A COLD FRONT WILL STALL JUST OFF THE EASTERN NORTH CAROLINA COAST TONIGHT. SLOW MOVING LOW PRESSURE WILL LIFT NORTHEAST ALONG THE STALLED FRONT MONDAY AND MONDAY NIGHT. THE LOW WILL FINALLY LIFT NORTHEAST OF THE REGION TUESDAY WITH THE TRAILING COLD FRONT GRADUALLY DISSIPATING AS IT DRIFTS OFF THE COAST. OFFSHORE HIGH PRESSURE WILL DOMINATE WEDNESDAY AND THURSDAY WITH ANOTHER COLD FRONT APPROACHING FROM THE WEST LATE IN THE WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1235 AM MONDAY...BASED ON SURFACE OBSERVATIONS IT NOW APPEARS THAT THE SURFACE FRONT HAS DRIFTED SOUTH INTO THE CAPE FEAR REGION. EASTERLY POST FRONTAL FLOW NOW IS OCCURRING ACROSS ALL OF EASTERN NC LATE TONIGHT WITH ONLY SPOTTY LIGHT SHOWERS OCCURRING. JUST TO THE NORTH OF THE BOUNDARY THUNDERSTORMS HAVE ERUPTED OVER ONSLOW COUNTY WITH ADDITIONAL CONVECTION DEVELOPING IN THE CAPE FEAR REGION AND LIFTING NORTH. THE 3 KM HRRR MODEL TAKES THIS PRECIPITATION NORTH ACROSS EASTERN NC LATE TONIGHT. THUS WILL HAVE POPS INCREASING TO LIKELY ALL AREAS AFTER 06Z AS THE MODEL DEVELOP A SLOW MOVING FRONTAL WAVE TO THE SOUTHWEST AND MOVE THIS FEATURE TOWARD EASTERN NC ON MONDAY. NO CHANGES NEEDED TO THE TEMPERATURE FORECAST. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 AM TUESDAY/... MODEL TRENDS AND CONCENSUS SUGGEST THE BEST CHANCES FOR HEAVIER PRECIPITATION WILL PUSH WESTWARD ALONG A DEVELOPING WEDGE FRONT ON MONDAY. WILL CONTINUE CATEGORICAL POPS INLAND AND TAPER BACK SLIGHTLY TO HIGH LIKELY POPS NEAR THE COAST. THERE WILL BE A CONTINUED THREAT FOR HEAVY RAIN AND LOCALIZED FLOODING JUST ABOUT ANYWHERE IN THE FORECAST AREA AND MAY EVENTUALLY NEED TO ISSUE FLOOD ADVISORIES OR WARNINGS IF HEAVIER/STEADIER RAIN FOCUSES IN ONE PARTICULAR AREA. HIGHS IN THE UPPER 70S TO LOWER 80S WITH MAINLY CLOUDY SKIES AND WIDESPREAD PRECIPITATION. && .LONG TERM /TUESDAY THROUGH MONDAY/... AS OF 4 PM SUN...AN UNSETTLED/WET PERIOD EXPECTED TO CONTINUE THROUGH TUE. THE COLD FRONT WILL REMAIN STALLED ACROSS THE AREA MON NIGHT...WITH AN AREA OF LOW PRESSURE MOVING ALONG THE BOUNDARY TUES INTO TUES NIGHT. THE STALLED BOUNDARY WILL BE A FOCUS FOR OCCASIONAL HEAVIER PRECIPITATION WITH GOOD UPPER LEVEL DIVERGENCE WITH THE REGION LOCATED IN THE RIGHT ENTRANCE OF THE UPPER JET AND PIECES OF SHORT WAVE ENERGY PUSHING THRU THE LOW AMPLITUDE MID LEVEL TROF OVER THE EASTERN STATES. MODEL PREFERENCES CONTINUE TO SIDE WITH A GFE/ECMWF BLEND AS THE NAM CONTINUES TO SHOW A DEEPER AND FASTER BIAS WITH THE SFC LOW TRACKING ACROSS THE AREA AND AS SUCH HAVE INCREASED POPS MON NIGHT INTO TUES WITH A SLOWER DEPARTURE OF THE LOW. FLOODING CONCERNS MAY CONTINUE INTO EARLY TUES WITH ADDITIONAL RAINFALL AMOUNTS IN THE 1-2 INCH RANGE POSSIBLE...WITH LOCALIZED HIGHER AMOUNTS POSSIBLE GIVEN THE HIGH PWATS OF 2 TO 2.25 INCHES. HIGHS WILL BE HELD DOWN BY CLOUDS AND PRECIP WITH MAX TEMPS UPPER 70S TO LOWER 80S TUE. THE LOW IS PROGGED TO LIFT NE OF THE REGION TUES NIGHT WITH THE FRONT FINALLY MOVING OFFSHORE WED...ALLOWING RIDGING/DEEP LAYER DRYING TO BUILD INTO THE AREA MIDWEEK. ONLY ISOLATED SEA BREEZE TYPE DIURNAL CONVECTION EXPECTED WED/THU AS SHORT WAVE RIDGE SUPPRESSES MOST CONVECTION. RISING THICKNESS WILL RESULT IN HIGH TEMPS MODERATING TO AT OR SLIGHTLY ABOVE NORMAL WED/THU...GENERALLY HIGHS IN THE LOWER TO UPPER 80S. ANOTHER COLD FRONT WILL MOVE INTO THE REGION LATE IN THE WEEK BUT THE USUAL TIMING ISSUES CONTINUE REGARDING THE APPROACH AND EVENTUAL PASSAGE OF THE FRONT. THERE IS ALMOST A 24 HR DIFFERENCE BETWEEN THE 12Z GFS AND 12Z ECMWF IN REGARD TO THE TIMING OF THE FRONT PUSHING SOUTH OF THE AREA LEADING TO BELOW AVERAGE CONFIDENCE IN THE FORECAST DETAILS LATE IN THE WEEK. PRECIP COULD BEGIN AS EARLY AS LATE THURS NIGHT WITH BEST CHANCES FRIDAY AFTERNOON THROUGH SAT...THEN TAPER OFF FROM N TO S SUNDAY. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... SHORT TERM /THROUGH MONDAY NIGHT/... AS OF 1235 AM MONDAY...SUB VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD IN WIDESPREAD PRECIPITATION...HEAVY AT TIMES WITH ASSOCIATED LOW CEILINGS AND VISIBILITIES. CONDITIONS WILL TEND TO BE VARIABLE BUT THINK IFR CEILINGS WILL PREVAIL INTO MONDAY MORNING THEN COULD LIFT TO MVFR BEFORE DROPPING AGAIN LATE MONDAY/MONDAY NIGHT AS SLOW MOVING LOW PRESSURE MOVES INTO THE AREA. LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 4 PM SUN...WIDESPREAD SHOWERS/THUNDERSTORMS WILL BRING PERIODS OF MVFR AND OCCASIONAL IFR CONDITIONS DURING AN UNSETTLED WEATHER PERIOD INTO TUE NIGHT AS A SFC FRONT STALLS OVER AND LOW PRES LIFTS ACROSS REGION. THERE IS A POTENTIAL FOR RADIATION FOG TUE NIGHT IF SKIES SUFFICIENTLY CLEAR AS LIGHT WINDS WILL PRODUCE A DECENT FOG SETUP ESPECIALLY WITH A SATURATED GROUND. GRADUAL DRYING IS EXPECTED WED AND THURS AS HIGH PRES BUILDS INTO THE AREA WITH PRED VFR CONDITIONS AND ONLY ISOL DIURNALLY DRIVEN CONVECTION...HOWEVER THERE IS A CHANCE OF MVFR CIGS LINGERING INTO WED WITH WRAP-AROUND MOISTURE ACROSS THE AREA BEHIND THE DEPARTING LOW. && .MARINE... SHORT TERM /TONIGHT/... AS OF 1235 AM MONDAY...FRONT IS NOW SOUTH OF THE WATERS WITH ALL OF THE NEAR-SHORE BUOYS NOW REPORTING N/NNE WINDS. SPEEDS ARE 15 KNOTS OR LESS AND GENERALLY 5 TO 10 KNOTS OVER ALL BUT THE FAR NORTHERN SECTIONS. PER LATEST 3 KM HRRR...WINDS SHOULD REMAIN NE/E THROUGH THE NIGHT WITH SEAS AT 2 TO 4 FEET. THE PRESSURE GRADIENT WILL TIGHTEN SOUTH OF THE FRONT AS LOW PRESSURE RIDES NE ALONG THE BNDRY MONDAY AND MAY REACH 15-20 KT MONDAY AFTERNOON OVER SOUTHERN AND CENTRAL WATERS. SEAS BUILD 3-5 FT IN RESPONSE TO THE WIND INCREASE. LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 4 PM SUN...A FRONTAL BOUNDARY WILL REMAIN STALLED ACROSS EASTERN NC WITH AREA OF LOW PRESSURE SLOWLY LIFTING ALONG THE FRONT MON NIGHT INTO WED. BELOW NORMAL CONFIDENCE IN THE MARINE FORECAST AS MODELS NOT IN BEST AGREEMENT WITH TIMING AND STRENGTH OF THE LOW. PREFERRED MODELS ARE A BLEND OF THE GFS/ECMWF WHICH IS SLOWER AND WEAKER WITH THE LOW AND THE FORECAST GENERALLY FOLLOWS THIS TREND WITH WINDS AROUND 10-20 KT. IF THE NAM ENDS UP VERIFYING WINDS COULD BE SIGNIFICANTLY STRONGER...AND CURRENTLY SHOWS WINDS AS HIGH AS 20-30 KT AHEAD OF THE LOW MON NIGHT. USED A BLEND OF THE NWPS AND WAVEWATCH III WITH SEAS PRIMARILY AROUND 3-5 FT...HOWEVER IF THE NAM VERIFIES HIGHER SEAS WILL BE LIKELY. THE LOW TRACKS OFF THE NC COAST WED WITH WINDS BECOMING LIGHT NW AS PRESSURE GRADIENT BECOMES WEAK ALONG THE COAST. WINDS GENERALLY LESS THAN 10KT WILL CONTINUE WED NIGHT INTO EARLY THU...BECOMING S/SW AGAIN 10-15KT BY LATE THU AFTERNOON AHEAD OF ANOTHER COLD FRONT. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SYNOPSIS...BTC NEAR TERM...CTC/JME SHORT TERM...BTC LONG TERM...BTC/SK AVIATION...JME/SK MARINE...CTC/BTC/JME/SK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1216 PM CDT MON SEP 8 2014 .UPDATE... ISSUED AT 1216 PM CDT MON SEP 8 2014 UPDATED THE FORECAST TO SCALE BACK THE SOUTHERN EXTENT OF THE CLOUD COVER FOR EARLY THIS AFTERNOON. THE FRONT`S SOUTHERN PROGRESSION HAS SLOWED DUE TO AFTERNOON HEATING SOUTH. HOWEVER...THE LATEST MESOSCALE MODELS PROG THE FRONT TO ACCELERATE SOUTHWARD DURING THE LATE AFTERNOON/EARLY EVENING HOURS WITH THE LOSS OF DAYTIME HEATING. THE REMAINING FORECAST ELEMENTS ARE IN GOOD SHAPE. THE UPDATED PRODUCTS HAVE BEEN SENT. UPDATE ISSUED AT 911 AM CDT MON SEP 8 2014 A COLD FRONT CONTINUES TO PROGRESS THROUGH NORTHWEST NORTH DAKOTA FASTER THAN PREVIOUSLY ANTICIPATED. FURTHERMORE...TRAILING STRATUS IS QUITE A BIT MORE WIDESPREAD UPSTREAM IN CANADA. AS A RESULT...UPDATED THE SKY GRIDS TO INCREASE CLOUD COVER NORTH BASED ON THE CURRENT OBS AND 06Z NAM 1000MB-850MB LAYER RH TRENDS. THE REMAINING WEATHER ELEMENTS ARE IN GOOD SHAPE. THE UPDATED PRODUCTS HAVE BEEN SENT. UPDATE ISSUED AT 634 AM CDT MON SEP 8 2014 GIVEN SATELLITE AND SURFACE OBSERVATION TRENDS THROUGH 11 UTC...THE COLD FRONT IS ARRIVING A BIT EARLIER INTO FAR NORTHEAST MONTANA AND NORTHWEST NORTH DAKOTA THAN PREVIOUSLY FORECAST. THE 10 UTC RAP AND 06 UTC NAM HAVE CAPTURED THIS WELL...AND HAVE BLENDED THE PREVIOUS FORECAST TO THEIR SOLUTIONS. THE RESULT...IS HIGHS ONLY IN THE UPPER 50S ACROSS THE FAR NORTHWEST UNDER LOW LEVEL STRATUS...AND UPPER 80S FOCUSED CLOSER TO THE SOUTH DAKOTA BORDER. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 343 AM CDT MON SEP 8 2014 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE THE ONSET OF A MAJOR PATTERN CHANGE LATER TODAY INTO TONIGHT. CURRENTLY...ARCTIC COLD FRONT...MODIFIED/WARMED AS IT HAS MOVED SOUTH ACROSS CENTRAL CANADA...CONTINUES TO PUSH SLOWLY SOUTHWARD ACROSS THE CENTRAL CANADIAN PRAIRIE PROVINCES AHEAD OF/IN RESPONSE TO A STRONG EMBEDDED IMPULSE ROTATING AROUND A DEEP AREA OF UPPER LEVEL LOW PRESSURE BUILDING ACROSS THE NORTHERN HUDSON BAY REGION. AHEAD OF THE FRONT...WAA SPREADING EAST ACROSS THE NORTHERN PLAINS ALONG TO SOUTH OF A SFC TROUGH. THE MODIFIED ARCTIC COLD FRONT WILL CONTINUE TO PUSH SOUTH REACHING THE INTERNATIONAL BORDER 12-15Z...AND THROUGH WEST AND CENTRAL NORTH DAKOTA LATER THIS EVENING. WILL INITIALLY SEE AN INCREASE IF LOW TO MID LEVEL CLOUDS ACROSS THE NORTH...ALONG WITH A WIND SHIFT FROM SOUTHERLY TO NORTHERLY. WILL KEEP THE FORECAST DRY THROUGH THE AFTERNOON WHEN MOISTURE IS MORE LIMITED. THE TIMING/PLACEMENT OF THE FRONT WILL CREATE A LARGE SPREAD IN DAYTIME HIGH TEMPERATURES TODAY...WITH MID/UPPER 60S NORTH AND MID/UPPER 80S SOUTH. DEEP LAYER MOISTURE WILL FILTER SOUTHWARD AFTER 00Z BEHIND THE FROPA...ALONG WITH A MODERATE NORTHEASTERLY UPSLOPE LOW LEVEL FLOW COMPONENT DEVELOPING NORTH TO SOUTH WITH LOW PRESSURE BUILDING ACROSS SOUTH DAKOTA. WILL MAINTAIN SLIGHT CHANCES FOR SHOWERS AS COVERAGE APPEARS TO BE LIMITED. STRATUS DEVELOPMENT LOOKING LIKELY SO KEPT SKY COVER ELEVATED. REMOVED THUNDER WITH LITTLE INSTABILITY ADVERTISED BY MODELS. DESPITE THE 0C ISOTHERM ENTERING MY NORTH LATE TONIGHT...CLOUD COVER SHOULD KEEP TEMPERATURES WELL ABOVE FROST/FREEZING THRESHOLDS FOR TONIGHT/TUESDAY MORNING. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 343 AM CDT MON SEP 8 2014 MUCH COOLER WEATHER AND FROST POTENTIAL CONTINUE TO HIGHLIGHT THE EXTENDED FORECAST. THE 00 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN GOOD AGREEMENT ON COOL HIGH PRESSURE BUILDING ACROSS NORTH DAKOTA TUESDAY THROUGH THURSDAY...WITH THE POTENTIAL COMMENCEMENT OF RETURN FLOW ACROSS THE NORTHERN PLAINS AND THE BEGINNING OF A WARMING TREND THIS WEEKEND AS THE HIGH WEAKENS AND DEPARTS IN THE GREAT LAKES. FROST IS POSSIBLE ACROSS WESTERN NORTH DAKOTA TUESDAY NIGHT...AND AREA WIDE WEDNESDAY AND THURSDAY NIGHTS WITH LOWS IN THE 30S. DEPENDING ON CLOUD COVER...SOME LOCATIONS MAY DROP BELOW FREEZING THURSDAY NIGHT. IN REGARDS TO PRECIPITATION...ANY SIGNIFICANT PRECIPITATION IS EXPECTED TO REMAIN TO OUR SOUTH AND EAST AS A COLORADO LOW PROPAGATES INTO THE MISSISSIPPI VALLEY TUESDAY INTO WEDNESDAY. SCATTERED RAIN SHOWERS ARE EXPECTED ON TUESDAY... WITH PERHAPS A RELATIVELY DRY WEDNESDAY WITH SOME SUBSIDENCE BEHIND THE TUESDAY SHORTWAVE. THE DISTURBANCE THAT HAD THE BEST POTENTIAL TO POSSIBLY YIELD SOME SNOW ACROSS NORTH DAKOTA THURSDAY IS NOW FORECAST TO MISS ALL BUT PERHAPS THE VERY FAR SOUTHWEST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1216 PM CDT MON SEP 8 2014 A STRONG COLD FRONT WILL CONTINUE TO SLOWLY PUSH SOUTH THIS AFTERNOON THROUGH EARLY EVENING. IFR STRATUS ASSOCIATED WITH THE FRONT MAY IMPACT KISN AND KMOT THIS EARLY AFTERNOON. MVFR TO NEAR IFR STRATUS IS FORECAST TO OVERSPREAD ALL OF WESTERN AND CENTRAL NORTH DAKOTA THIS EVENING AND CONTINUE THROUGH THE REMAINDER OF THE TAF PERIOD. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TM SHORT TERM...NH LONG TERM...AYD AVIATION...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
911 AM CDT MON SEP 8 2014 .UPDATE... ISSUED AT 911 AM CDT MON SEP 8 2014 A COLD FRONT CONTINUES TO PROGRESS THROUGH NORTHWEST NORTH DAKOTA FASTER THAN PREVIOUSLY ANTICIPATED. FURTHERMORE...TRAILING STRATUS IS QUITE A BIT MORE WIDESPREAD UPSTREAM IN CANADA. AS A RESULT...UPDATED THE SKY GRIDS TO INCREASE CLOUD COVER NORTH BASED ON THE CURRENT OBS AND 06Z NAM 1000MB-850MB LAYER RH TRENDS. THE REMAINING WEATHER ELEMENTS ARE IN GOOD SHAPE. THE UPDATED PRODUCTS HAVE BEEN SENT. UPDATE ISSUED AT 634 AM CDT MON SEP 8 2014 GIVEN SATELLITE AND SURFACE OBSERVATION TRENDS THROUGH 11 UTC...THE COLD FRONT IS ARRIVING A BIT EARLIER INTO FAR NORTHEAST MONTANA AND NORTHWEST NORTH DAKOTA THAN PREVIOUSLY FORECAST. THE 10 UTC RAP AND 06 UTC NAM HAVE CAPTURED THIS WELL...AND HAVE BLENDED THE PREVIOUS FORECAST TO THEIR SOLUTIONS. THE RESULT...IS HIGHS ONLY IN THE UPPER 50S ACROSS THE FAR NORTHWEST UNDER LOW LEVEL STRATUS...AND UPPER 80S FOCUSED CLOSER TO THE SOUTH DAKOTA BORDER. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 343 AM CDT MON SEP 8 2014 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE THE ONSET OF A MAJOR PATTERN CHANGE LATER TODAY INTO TONIGHT. CURRENTLY...ARCTIC COLD FRONT...MODIFIED/WARMED AS IT HAS MOVED SOUTH ACROSS CENTRAL CANADA...CONTINUES TO PUSH SLOWLY SOUTHWARD ACROSS THE CENTRAL CANADIAN PRAIRIE PROVINCES AHEAD OF/IN RESPONSE TO A STRONG EMBEDDED IMPULSE ROTATING AROUND A DEEP AREA OF UPPER LEVEL LOW PRESSURE BUILDING ACROSS THE NORTHERN HUDSON BAY REGION. AHEAD OF THE FRONT...WAA SPREADING EAST ACROSS THE NORTHERN PLAINS ALONG TO SOUTH OF A SFC TROUGH. THE MODIFIED ARCTIC COLD FRONT WILL CONTINUE TO PUSH SOUTH REACHING THE INTERNATIONAL BORDER 12-15Z...AND THROUGH WEST AND CENTRAL NORTH DAKOTA LATER THIS EVENING. WILL INITIALLY SEE AN INCREASE IF LOW TO MID LEVEL CLOUDS ACROSS THE NORTH...ALONG WITH A WIND SHIFT FROM SOUTHERLY TO NORTHERLY. WILL KEEP THE FORECAST DRY THROUGH THE AFTERNOON WHEN MOISTURE IS MORE LIMITED. THE TIMING/PLACEMENT OF THE FRONT WILL CREATE A LARGE SPREAD IN DAYTIME HIGH TEMPERATURES TODAY...WITH MID/UPPER 60S NORTH AND MID/UPPER 80S SOUTH. DEEP LAYER MOISTURE WILL FILTER SOUTHWARD AFTER 00Z BEHIND THE FROPA...ALONG WITH A MODERATE NORTHEASTERLY UPSLOPE LOW LEVEL FLOW COMPONENT DEVELOPING NORTH TO SOUTH WITH LOW PRESSURE BUILDING ACROSS SOUTH DAKOTA. WILL MAINTAIN SLIGHT CHANCES FOR SHOWERS AS COVERAGE APPEARS TO BE LIMITED. STRATUS DEVELOPMENT LOOKING LIKELY SO KEPT SKY COVER ELEVATED. REMOVED THUNDER WITH LITTLE INSTABILITY ADVERTISED BY MODELS. DESPITE THE 0C ISOTHERM ENTERING MY NORTH LATE TONIGHT...CLOUD COVER SHOULD KEEP TEMPERATURES WELL ABOVE FROST/FREEZING THRESHOLDS FOR TONIGHT/TUESDAY MORNING. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 343 AM CDT MON SEP 8 2014 MUCH COOLER WEATHER AND FROST POTENTIAL CONTINUE TO HIGHLIGHT THE EXTENDED FORECAST. THE 00 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN GOOD AGREEMENT ON COOL HIGH PRESSURE BUILDING ACROSS NORTH DAKOTA TUESDAY THROUGH THURSDAY...WITH THE POTENTIAL COMMENCEMENT OF RETURN FLOW ACROSS THE NORTHERN PLAINS AND THE BEGINNING OF A WARMING TREND THIS WEEKEND AS THE HIGH WEAKENS AND DEPARTS IN THE GREAT LAKES. FROST IS POSSIBLE ACROSS WESTERN NORTH DAKOTA TUESDAY NIGHT...AND AREA WIDE WEDNESDAY AND THURSDAY NIGHTS WITH LOWS IN THE 30S. DEPENDING ON CLOUD COVER...SOME LOCATIONS MAY DROP BELOW FREEZING THURSDAY NIGHT. IN REGARDS TO PRECIPITATION...ANY SIGNIFICANT PRECIPITATION IS EXPECTED TO REMAIN TO OUR SOUTH AND EAST AS A COLORADO LOW PROPAGATES INTO THE MISSISSIPPI VALLEY TUESDAY INTO WEDNESDAY. SCATTERED RAIN SHOWERS ARE EXPECTED ON TUESDAY... WITH PERHAPS A RELATIVELY DRY WEDNESDAY WITH SOME SUBSIDENCE BEHIND THE TUESDAY SHORTWAVE. THE DISTURBANCE THAT HAD THE BEST POTENTIAL TO POSSIBLY YIELD SOME SNOW ACROSS NORTH DAKOTA THURSDAY IS NOW FORECAST TO MISS ALL BUT PERHAPS THE VERY FAR SOUTHWEST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 634 AM CDT MON SEP 8 2014 A STRONG COLD FRONT IS BEGINNING TO ARRIVE INTO FAR NORTHWEST NORTH DAKOTA AS OF 1130 UTC...MOVING SOUTHEAST THROUGH THE DAY. IFR STRATUS ASSOCIATED WITH THE FRONT MAY IMPACT KISN AND KMOT THIS MORNING INTO THE EARLY AFTERNOON. MVFR TO NEAR IFR STRATUS IS FORECAST TO OVERSPREAD ALL OF WESTERN AND CENTRAL NORTH DAKOTA THIS EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TM SHORT TERM...NH LONG TERM...AYD AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
635 AM CDT MON SEP 8 2014 .UPDATE... ISSUED AT 634 AM CDT MON SEP 8 2014 GIVEN SATELLITE AND SURFACE OBSERVATION TRENDS THROUGH 11 UTC...THE COLD FRONT IS ARRIVING A BIT EARLIER INTO FAR NORTHEAST MONTANA AND NORTHWEST NORTH DAKOTA THAN PREVIOUSLY FORECAST. THE 10 UTC RAP AND 06 UTC NAM HAVE CAPTURED THIS WELL...AND HAVE BLENDED THE PREVIOUS FORECAST TO THEIR SOLUTIONS. THE RESULT...IS HIGHS ONLY IN THE UPPER 50S ACROSS THE FAR NORTHWEST UNDER LOW LEVEL STRATUS...AND UPPER 80S FOCUSED CLOSER TO THE SOUTH DAKOTA BORDER. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 343 AM CDT MON SEP 8 2014 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE THE ONSET OF A MAJOR PATTERN CHANGE LATER TODAY INTO TONIGHT. CURRENTLY...ARCTIC COLD FRONT...MODIFIED/WARMED AS IT HAS MOVED SOUTH ACROSS CENTRAL CANADA...CONTINUES TO PUSH SLOWLY SOUTHWARD ACROSS THE CENTRAL CANADIAN PRAIRIE PROVINCES AHEAD OF/IN RESPONSE TO A STRONG EMBEDDED IMPULSE ROTATING AROUND A DEEP AREA OF UPPER LEVEL LOW PRESSURE BUILDING ACROSS THE NORTHERN HUDSON BAY REGION. AHEAD OF THE FRONT...WAA SPREADING EAST ACROSS THE NORTHERN PLAINS ALONG TO SOUTH OF A SFC TROUGH. THE MODIFIED ARCTIC COLD FRONT WILL CONTINUE TO PUSH SOUTH REACHING THE INTERNATIONAL BORDER 12-15Z...AND THROUGH WEST AND CENTRAL NORTH DAKOTA LATER THIS EVENING. WILL INITIALLY SEE AN INCREASE IF LOW TO MID LEVEL CLOUDS ACROSS THE NORTH...ALONG WITH A WIND SHIFT FROM SOUTHERLY TO NORTHERLY. WILL KEEP THE FORECAST DRY THROUGH THE AFTERNOON WHEN MOISTURE IS MORE LIMITED. THE TIMING/PLACEMENT OF THE FRONT WILL CREATE A LARGE SPREAD IN DAYTIME HIGH TEMPERATURES TODAY...WITH MID/UPPER 60S NORTH AND MID/UPPER 80S SOUTH. DEEP LAYER MOISTURE WILL FILTER SOUTHWARD AFTER 00Z BEHIND THE FROPA...ALONG WITH A MODERATE NORTHEASTERLY UPSLOPE LOW LEVEL FLOW COMPONENT DEVELOPING NORTH TO SOUTH WITH LOW PRESSURE BUILDING ACROSS SOUTH DAKOTA. WILL MAINTAIN SLIGHT CHANCES FOR SHOWERS AS COVERAGE APPEARS TO BE LIMITED. STRATUS DEVELOPMENT LOOKING LIKELY SO KEPT SKY COVER ELEVATED. REMOVED THUNDER WITH LITTLE INSTABILITY ADVERTISED BY MODELS. DESPITE THE 0C ISOTHERM ENTERING MY NORTH LATE TONIGHT...CLOUD COVER SHOULD KEEP TEMPERATURES WELL ABOVE FROST/FREEZING THRESHOLDS FOR TONIGHT/TUESDAY MORNING. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 343 AM CDT MON SEP 8 2014 MUCH COOLER WEATHER AND FROST POTENTIAL CONTINUE TO HIGHLIGHT THE EXTENDED FORECAST. THE 00 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN GOOD AGREEMENT ON COOL HIGH PRESSURE BUILDING ACROSS NORTH DAKOTA TUESDAY THROUGH THURSDAY...WITH THE POTENTIAL COMMENCEMENT OF RETURN FLOW ACROSS THE NORTHERN PLAINS AND THE BEGINNING OF A WARMING TREND THIS WEEKEND AS THE HIGH WEAKENS AND DEPARTS IN THE GREAT LAKES. FROST IS POSSIBLE ACROSS WESTERN NORTH DAKOTA TUESDAY NIGHT...AND AREA WIDE WEDNESDAY AND THURSDAY NIGHTS WITH LOWS IN THE 30S. DEPENDING ON CLOUD COVER...SOME LOCATIONS MAY DROP BELOW FREEZING THURSDAY NIGHT. IN REGARDS TO PRECIPITATION...ANY SIGNIFICANT PRECIPITATION IS EXPECTED TO REMAIN TO OUR SOUTH AND EAST AS A COLORADO LOW PROPAGATES INTO THE MISSISSIPPI VALLEY TUESDAY INTO WEDNESDAY. SCATTERED RAIN SHOWERS ARE EXPECTED ON TUESDAY... WITH PERHAPS A RELATIVELY DRY WEDNESDAY WITH SOME SUBSIDENCE BEHIND THE TUESDAY SHORTWAVE. THE DISTURBANCE THAT HAD THE BEST POTENTIAL TO POSSIBLY YIELD SOME SNOW ACROSS NORTH DAKOTA THURSDAY IS NOW FORECAST TO MISS ALL BUT PERHAPS THE VERY FAR SOUTHWEST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 634 AM CDT MON SEP 8 2014 A STRONG COLD FRONT IS BEGINNING TO ARRIVE INTO FAR NORTHWEST NORTH DAKOTA AS OF 1130 UTC...MOVING SOUTHEAST THROUGH THE DAY. IFR STRATUS ASSOCIATED WITH THE FRONT MAY IMPACT KISN AND KMOT THIS MORNING INTO THE EARLY AFTERNOON. MVFR TO NEAR IFR STRATUS IS FORECAST TO OVERSPREAD ALL OF WESTERN AND CENTRAL NORTH DAKOTA THIS EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD SHORT TERM...NH LONG TERM...AYD AVIATION...AYD
AREA FORECAST DISCUSSION
NWS MEDFORD OR
224 PM PDT MON SEP 8 2014 .DISCUSSION...AS FAR AS THE GENERAL FORECAST GOES, THE PERIOD OF QUIET AND UNEVENTFUL WEATHER WILL CONTINUE THROUGH AT LEAST THE NEXT WEEK. MODELS ARE IN FAIRLY GOOD AGREEMENT CONCERNING THE OVERALL PATTERN, WITH THE USUAL AND EXPECTED DIVERSION OF SOLUTIONS LATER IN THE TERM. HAVE KEPT THE FORECAST TRENDED TOWARDS A GENERAL MODEL BLEND. THE UPPER LOW CURRENTLY OVEN NORTHERN CALIFORNIA WILL WORK ITS WAY EAST THROUGH TONIGHT AS A WEAK DRY COLD FRONT PUSHES IN FROM THE NORTHWEST THIS EVENING. ALTHOUGH INSTABILITY IS WEAK, LAPSE RATES ARE PRETTY STEEP IN SOME AREAS, AND MOISTURE WILL BE INCREASED IN THE MID LEVELS. HIGH RESOLUTION NAM AND HRRR RUNS HAVE ALSO PRODUCED VARYING AMOUNTS OF REFLECTIVITY OVER THE AREA. WITH ALL THIS IN MIND, HAVE KEPT THE SLIGHT CHANCE OF THUNDER THAT WAS INTRODUCED DURING THIS MORNING`S UPDATE, BUT CONFIDENCE REMAINS LOW. AS MENTIONED ABOVE, THE WEAK FRONT WILL MOVE THROUGH THE AREA THIS AFTERNOON AND EVENING, WITH TEMPERATURES COMING DOWN CLOSER TO SEASONAL NORMS TUESDAY AND POSSIBLY WEDNESDAY. THE FRONT WILL ALSO BRING GUSTY, BUT NOT STRONG, WINDS TO AREAS EAST OF THE CASCADES. ONSHORE FLOW BEHIND THE FRONT WILL KEEP LOW CLOUDS AT THE COAST LONGER DURING THE DAY WITH A GOOD CHANCE OF SEEING STRATUS SPREADING INTO THE ROSEBURG AREA TONIGHT AND TUESDAY MORNING. BOTH THE NAM12 AND TO A CERTAIN EXTENT THE GFS BRING SOME MOISTURE SOUTH OF THE UMPQUA DIVIDE EARLY TUESDAY MORNING. CONFIDENCE IS NOT VERY HIGH THAT WE WILL SEE CLOUDS IN MEDFORD. STEERING WINDS ARE EXPECTED TO TURN BACK TO THE NORTHWEST THIS AFTERNOON AND STAY NW THROUGH TUESDAY. THIS SHOULD PUSH THE SMOKE BACK INTO SISKIYOU COUNTY BUT COULD PRESENT PROBLEMS FOR YREKA AND MOUNT SHASTA AREA. EXPECT WARMING TREND TO RETURN AGAIN ON THURSDAY AND STAY WITH US THROUGH NEXT WEEKEND...AS A MIDLEVEL RIDGE BUILDS IN OVERHEAD AND THE THERMAL TROUGH RETURNS AND EXTENDS NORTHWARD WEST OF THE CASCADES. TEMPERATURES WILL REMAIN NEAR NORMAL VALUES ON THE EAST SIDE, AND THIS DIFFERENCE IN TEMPERATURE AND PRESSURE WILL LIKELY RESULT IN SOME STRONGER EAST WINDS WEDNESDAY NIGHT INTO THURSDAY. THIS WILL LEAD TO ANOTHER ROUND OF INCREASED FIRE CONCERNS INTO THE WEEKEND. MODEL SOLUTIONS ARE SHOWING A POSSIBLE LARGER TROUGH ENTERING THE AREA FROM THE NORTHEAST PACIFIC EARLY NEXT WEEK, BUT CONFIDENCE IS LOW, ESPECIALLY GIVEN THE BLOCKY LOOKING PATTERN PRODUCED UPSTREAM BY THE HEMISPHERICAL MODELS DURING THE SAME PERIOD. GIVEN THE UNCERTAINTY, THE FORECAST REMAINS DRY THROUGH THE TERM. -BPN && .AVIATION...BASED ON THE 08/18Z TAF CYCLE...CURRENT VISIBLE IMAGE SHOWS THE MARINE STRATUS GRADUALLY PEELING BACK TOWARDS THE COAST. BASED ON THE SATELLITE TREND, VFR CONDITIONS COULD DEVELOP FOR A COUPLE OF HOURS AT KOTH AFTER 22Z. UNTIL THEN IFR/LIFR CONDITIONS WILL PERSIST WITH GUSTY NORTHERLY WINDS INTO EARLY EVENING. IFR/LIFT CIGS WILL RETURN THIS EVENING AND CONTINUES INTO TUESDAY MORNING. ELSEWHERE VFR CONDITIONS WILL CONTINUE FOR THE NEXT 18 HOURS, EXCEPT FOR OCCASIONAL REDUCTION IN VIS DUE TO AREAS OF SMOKE IN WESTERN SISKIYOU COUNTY. MODELS SUGGEST MARINE STRATUS WILL PUSH INTO THE UMPQUA BASIN TOWARDS DAY BREAK TUESDAY WITH WIDESPREAD MVFR CIGS AND PARTIAL MTN OBSCURATIONS. IT`S POSSIBLE SOME OF THE MARINE STRATUS COULD. SPILL OVER THE UMPQUA DIVIDE, BUT SHOULD NOT EFFECT KMFR. -PETRUCELLI && .MARINE...UPDATED 220 PM PDT MON 8 SEP 2014...HIGH PRESSURE WILL CONTINUE TO BUILD OFFSHORE THIS AFTERNOON AND A THERMAL TROUGH WILL REDEVELOP ALONG THE COAST. THIS WILL RESULT IN THE RETURN OF NORTH WINDS AND WIND WAVE DOMINATED SEAS THROUGH THE UPCOMING WEEK. NORTH WINDS ARE LIKELY TO BE STRONGEST TUESDAY THROUGH WEDNESDAY WITH GALES POSSIBLE SOUTH OF CAPE BLANCO. -WRIGHT && .FIRE WEATHER...LATEST VISIBLE IMAGE SHOWS SOME CUMULUS BUILD UPS AROUND THE SHASTA TRINITY NORTHEAST THROUGH MEDICINE BOW PEAK AND SOUTHEAST MODOC COUNTY. SOME ARE DEVELOPING OVER THE CASCADES AND HIGHER TERRAIN ON THE EAST SIDE. THE MODELS HINT AT VERY WEAK INSTABILITY LATE THIS AFTERNOON INTO THIS EVENING. THE MODELS SHOW SOME INSTABILITY IN THE AFOREMENTIONED AREAS, BUT IT`S MARGINAL AT BEST. MODELS SOUNDINGS SHOW A WEAK CAP, SO IT`S POSSIBLE THAT THERE MAY NOT BE A LOT OF VERTICAL DEVELOPMENT. IF ANY ISOLATED STORMS WERE TO DEVELOP, IT WOULD MOST LIKELY BE BETWEEN 4-8 PM PDT. THE MAIN CONCERN WILL BE GUSTY WEST TO NORTHWEST WINDS ON THE MID SLOPES AND RIDGES LATE THIS AFTERNOON AND EVENING AS A DRY COLD FRONT MOVES THROUGH. AN UPPER TROUGH WILL MOVE NORTH OF THE AREA TUESDAY AND THE MODELS ARE SUGGESTING WEST TO NORTHWEST WINDS TUESDAY AFTERNOON AND EVENING COULD BE HIGHER. THE GOOD NEWS IS THAT RELATIVE HUMIDITIES WILL BE HIGHER, SO WERE NOT EXPECTING RED FLAG CONDITIONS TO BE MET. THEREFORE WE`LL CONTINUE TO HEADLINE IT IN THE FORECAST. A STRONGER SHORTWAVE WILL SWING THROUGH IDAHO AND WESTERN MONTANA WITH STRONG HIGH PRESSURE BUILDING SOUTH INTO EASTERN WASHINGTON AND NORTHEAST OREGON BY THURSDAY MORNING. A THERMAL TROUGH WILL DEVELOP ALONG THE OREGON COAST AND THE PATTERN DEVELOPING IS FAVORABLE TO MODERATE TO STRONG OFFSHORE FLOW ALONG THE CASCADES AND POSSIBLY WESTERN SISKIYOU COUNTY. ALSO THE MODEL SOUNDINGS SHOW A SUBSIDENCE INVERSION WHICH COULD RESULT IN MODERATE TO POOR RECOVERIES WEDNESDAY NIGHT. THE COMBINATION OF MODERATE TO POOR RECOVERIES AND WIND COULD WARRANT RED FLAG CONDITIONS, BUT THERE`S STILL TIME TO EVALUATE THIS. FOR NOW WE`LL HEADLINE FOR THIS POTENTIAL JUST TO RAISE AWARENESS TO THE USERS. -PETRUCELLI && .MFR WATCHES/WARNINGS/ADVISORIES... OR... CA...NONE. PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT WEDNESDAY FOR PZZ356-376. HAZARDOUS SEAS WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR PZZ356-376. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT WEDNESDAY FOR PZZ350-356-370-376. SMALL CRAFT ADVISORY FOR WINDS FROM 5 PM TUESDAY TO 11 PM PDT WEDNESDAY FOR PZZ350-370. GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR PZZ376. $$ BPN/MAP/TRW
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1231 PM CDT MON SEP 8 2014 .AVIATION 18Z DISCUSSION... LOW CLOUDINESS TO PERSIST FOR A FEW MORE HOURS BUT WILL BEGIN TO BREAK UP TOWARD AND BEYOND 00Z. LOW LEVEL MOISTURE WILL STILL REMAIN...HOWEVER...AND FOG FORMATION CAN BE EXPECTED OVERNIGHT. SOME SCT TO BKN LOW LEVEL CIGS CAN AGAIN BE EXPECTED AROUND 12Z TOMORROW...MAINLY ACROSS THE PLATEAU AREA. && .PREV DISCUSSION... /ISSUED 935 AM CDT MON SEP 8 2014/ DISCUSSION... LOW CLOUDINESS HANGING ON ACROSS MUCH OF THE MID STATE THIS MORNING. THE CLEARING LINE EXTENDS FROM JUST EAST OF CKV SOUTHWEST THROUGH LOBELVILLE. THE LATEST 12Z SOUNDING PAIRED WITH THE NAM THINKING INDICATES THAT THESE CLOUDS ARE GOING TO BE RATHER TOUGH TO DISLODGE. THEREFORE...FOR THE UPDATE...WILL GO AHEAD AND LOWER TEMPS A GOOD 3-5 DEGREES OR SO...MAINLY FOR THE EASTERN HALF OF THE AREA. WILL ADJUST SKY GRIDS ACCORDINGLY. OTW...WILL KEEP A SLIGHT CHANCE OF SHOWERS AND TSTMS GOING ACROSS THE PLATEAU. LATEST HRRR DOES SHOW SOME CONVECTIVE DEVELOPMENT THIS AFTERNOON. WILL REMOVE THE MORNING 12Z-18Z PART OF THE SLIGHT CHANCE WEATHER GRID. UPDATE OUT SHORTLY. PREV DISCUSSION... /ISSUED 653 AM CDT MON SEP 8 2014/ UPDATE...FOR 12Z AVIATION FORECASTS. AVIATION...BAND OF LOW CLOUDS THAT COVERED THE SOUTHEASTERN TWO- THIRDS OF MIDDLE TN EARLY THIS MORNING, WILL SLOWLY BREAK FROM THE WEST. MVFR CIGS ARE EXPECTED TO HOLD AT BNA THROUGH 18Z, WITH CSV HOLDING ON TO IFR CONDITIONS THROUGH 15Z, THEN MVFR THROUGH AT LEAST 20Z. MEANWHILE, CKV SHOULD CONTINUE TO ENJOY VFR CONDITIONS. FOR TONIGHT...EXPECT CKV AND BNA TO EXPERIENCE VFR CONDITIONS, WHILE CSV WILL PROBABLY STILL BE PESTERED BY PERIODS OF LOW CLOUDS AND FOG, ESPECIALLY DURING THE LATTER PART OF THE NIGHT. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 21
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
935 AM CDT MON SEP 8 2014 .DISCUSSION... LOW CLOUDINESS HANGING ON ACROSS MUCH OF THE MID STATE THIS MORNING. THE CLEARING LINE EXTENDS FROM JUST EAST OF CKV SOUTHWEST THROUGH LOBELVILLE. THE LATEST 12Z SOUNDING PAIRED WITH THE NAM THINKING INDICATES THAT THESE CLOUDS ARE GOING TO BE RATHER TOUGH TO DISLODGE. THEREFORE...FOR THE UPDATE...WILL GO AHEAD AND LOWER TEMPS A GOOD 3-5 DEGREES OR SO...MAINLY FOR THE EASTERN HALF OF THE AREA. WILL ADJUST SKY GRIDS ACCORDINGLY. OTW...WILL KEEP A SLIGHT CHANCE OF SHOWERS AND TSTMS GOING ACROSS THE PLATEAU. LATEST HRRR DOES SHOW SOME CONVECTIVE DEVELOPMENT THIS AFTERNOON. WILL REMOVE THE MORNING 12Z-18Z PART OF THE SLIGHT CHANCE WEATHER GRID. UPDATE OUT SHORTLY. && .PREV DISCUSSION... /ISSUED 653 AM CDT MON SEP 8 2014/ UPDATE...FOR 12Z AVIATION FORECASTS. AVIATION...BAND OF LOW CLOUDS THAT COVERED THE SOUTHEASTERN TWO- THIRDS OF MIDDLE TN EARLY THIS MORNING, WILL SLOWLY BREAK FROM THE WEST. MVFR CIGS ARE EXPECTED TO HOLD AT BNA THROUGH 18Z, WITH CSV HOLDING ON TO IFR CONDITIONS THROUGH 15Z, THEN MVFR THROUGH AT LEAST 20Z. MEANWHILE, CKV SHOULD CONTINUE TO ENJOY VFR CONDITIONS. FOR TONIGHT...EXPECT CKV AND BNA TO EXPERIENCE VFR CONDITIONS, WHILE CSV WILL PROBABLY STILL BE PESTERED BY PERIODS OF LOW CLOUDS AND FOG, ESPECIALLY DURING THE LATTER PART OF THE NIGHT. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 86 65 90 70 / 10 05 0 05 CLARKSVILLE 85 61 88 68 / 05 05 0 05 CROSSVILLE 79 64 83 68 / 30 10 20 05 COLUMBIA 85 66 90 67 / 10 05 0 05 LAWRENCEBURG 85 66 89 68 / 10 05 05 05 WAVERLY 85 63 88 69 / 05 05 0 05 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 21
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1140 PM CDT SUN SEP 7 2014 .AVIATION... /06Z TAFS/ Patchy stratus with MVFR ceilings possible daybreak into into mid morning. Otherwise light winds and mid level clouds will prevail overnight with south winds increasing to 5-10 KTS mid morning. With light winds and evening rainfall near KSOA and KJCT, there is the potential for patchy fog, mainly MVFR, near sunrise. However, mid level clouds and morning stratus may limit widespread formation. && .PREV DISCUSSION... /ISSUED 635 PM CDT SUN SEP 7 2014/ AVIATION... /00Z TAFS/ Thunderstorm outflow boundary will move through KSJT around 0030Z, temporarily shifting winds to the south with gusts to 20 KTS. Thunderstorms will be in the vicinity until 2Z. With low levels of the atmosphere remaining moist, stratus expected with MVFR CIGS late tonight, beginning at climatologically favorable times and scattering out mid to late Monday morning. PREV DISCUSSION... /ISSUED 313 PM CDT SUN SEP 7 2014/ SHORT TERM... (Tonight and tomorrow) The quasi-stationary front is currently analyzed very near the southern border of the CWA, roughly along a line from Sheffield, to Rock Springs, to San Antonio. Skies cleared by midday across the I-10 corridor, allowing temperatures to warm into the mid 80s. MLCAPE values around 1000-1500 J/kg are present from Ozona to Junction per the RAP Mesoanalysis, but CINH is no longer a concern in this area. Scattered showers and thunderstorms have developed in the vicinity of this boundary and will move to the northwest during the afternoon and evening hours. Rain chances tonight will primarily be limited to locations south of a Sterling City to Brownwood line. The primary concern will be locally heavy rainfall given the slow storm motions and precipitable water values around 1.75". This could result in minor flooding, mainly in urban areas. Low temperatures tonight should be in the upper 60s. On Monday, we`ll maintain a moist airmass across West Central TX. Precipitable water values are progged to remain at or above 1.60", but the surface boundary is progged to wash out as southerly flow resumes across the region. The loss of a low-level forcing mechanism will limit rain chances. However, with temperatures warming into the lower 90s, we should still see diurnal isolated convection across the area. The best rain chances will be over the northwest Hill Country, but isolated showers and thunderstorms will be included for much of the area east of a Sonora, to San Angelo, to Sweetwater line. Johnson LONG TERM... (Tomorrow night through Sunday) A cold front will bring a chance of showers and thunderstorms and cooler temperatures for the latter part of the work week... Above normal temperatures are forecast on Tuesday, with highs ranging from the lower to mid 90s across the Interstate 10 corridor, to the mid to upper 90s across the Big Country. Overnight lows will be int he mid 70s. In the meantime, an upper level trough will move into the Northern Rockies, and then eventually into the Northern Plains, sending a cold front into the northern Big Country Wednesday evening. Ahead of the cold front, compressional heating will result in unseasonably hot temperatures on Wednesday. Highs will generally be in the mid to upper 90s. Models continue to have timing differences with regard to the aforementioned cold front. Both the ECMWF and the GFS bring a front into the Big Country Wednesdays night, then eventually slowly move it through much of the rest of West Central Texas during the day Thursday. Showers and thunderstorms are forecast to develop along the front, with the best chance across the Big Country initially, then better chances spreading south into much of the rest of the area Thursday into Thursday night. High temperatures on Thursday will be dependent on the timing of the front and any associated rainfall. For now, the forecast reflects highs in the mid 80s across the Big Country to the lower 90s across the Interstate 10 corridor. Beyond Thursday, the GFS pushes the front through the area, while the ECMWF dissipates the boundary, with a stronger cold front moving through during the day on Friday. For now, the forecast was geared toward the faster GFS solution, with PoPs decreasing from north to south Friday. If the ECMWF solution were to verify, higher PoPs would linger into Friday/Friday night. Highs on Friday were trended down, given the expected cloud cover and cold air advection. Highs will range from the lower 70s in the Big Country to near 80 along the Interstate 10 corridor. These temperatures may eventually need to be trended down a bit. A slow warm up is forecast into next weekend. Daniels && .PRELIMINARY POINT TEMPS/POPS... Abilene 66 91 71 96 75 / 10 10 5 5 5 San Angelo 67 92 71 96 75 / 20 10 5 5 5 Junction 68 90 71 95 74 / 20 20 10 5 5 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99/04
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1000 PM CDT TUE SEP 9 2014 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .UPDATE... ISSUED AT 1000 PM CDT TUE SEP 9 2014 WILL CONTINUE FLOOD WATCH AS SYSTEM STILL APPEARS IT WILL COME TOGETHER ACROSS THE STATE...THOUGH THERE COULD BE TWO AREAS OF MAXIMUM RAIN WITH ONE ACROSS THE NORTH AND ANOTHER SOUTH. SUBSTANTIAL LIFT...STRONG LOW-LEVEL JET...AND HIGH PRECIPITABLE WATER VALUES SHOULD RESULT IN WIDESPREAD 1+ INCH VALUES. HEAVIEST RAIN SHOULD FALL BETWEEN ABOUT 09Z AND 15Z. && .SHORT TERM...TONIGHT AND WEDNESDAY ISSUED AT 245 PM CDT TUE SEP 9 2014 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG COLD FRONT MOVING SOUTHEAST ACROSS NORTHERN MINNESOTA AND SOUTH DAKOTA...WHILE LOW PRESSURE IS EMERGING INTO WESTERN KANSAS. AN ISOLATED THUNDERSTORM DROPPED A QUARTER OF AN INCH OF RAIN OVER WAUSAU EARLIER THIS MORNING WITHIN A MODEST MOISTURE AXIS BUT DIMINISHED BY MIDDAY. OTHERWISE...NO OTHER CONVECTION HAS DEVELOPED SO FAR TODAY. THUNDERSTORM ACTIVITY CONTINUES TO EXPAND OVER NEBRASKA AND IOWA IN AN AREA OF MOISTURE CONVERGENCE AT 850MB. AS LOW PRESSURE MOVES EAST AND THE LLJ MATURES THIS EVENING...THIS AREA WILL DRAW ATTENTION FOR THE POTENTIAL OF SEVERE WEATHER AND HEAVY RAIN DOWNSTREAM OVER CENTRAL AND NORTHEAST WISCONSIN LATER TONIGHT. ANOTHER AREA OF RAIN CONTINUES TO DEVELOP OVER THE EASTERN DAKOTAS. AS THESE SYSTEMS MOVE EAST...SEVERE WEATHER AND HEAVY RAIN POTENTIAL ARE THE MAIN FORECAST CONCERNS. TONIGHT...FOLLOWED THE ECMWF AND SREF FOR THE DETAILS OF THIS FORECAST...WHICH IS PREFERRED BY HPC AND SUPPORTED BY THE ENSEMBLE MEANS. THESE MODELS SHOW THAT THE STRONG COLD FRONT OVER THE NORTHERN PLAINS WILL SAG SOUTH INTO NORTH-CENTRAL WISCONSIN THIS EVENING AS LOW PRESSURE TRACKS NORTHEAST ACROSS THE CENTRAL PLAINS. AHEAD OF THIS LOW...MID-LEVEL FLOW WILL BE BACKING WHILE INCREASING AT THE SAME TIME...LEADING TO INCREASING ISENTROPIC ASCENT IN THE PRESENCE OF MID-LEVEL LAPSE RATES BETWEEN 6-7 C/KM THROUGH THE EVENING. WEAK SHORTWAVE ENERGY AND UPPER DIVERGENCE WILL ALSO BE APPROACHING BY LATE IN THE EVENING. THIS ALL POINTS TO INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS FROM WEST TO EAST THROUGH THE EVENING. PRECIP MAY BE MORE OF THE SCATTERED VARIETY DURING THE EVENING...BUT THE MAIN SHOW LOOKS TO ARRIVE AFTER MIDNIGHT FROM THE SOUTHWEST. AS THE LOW MOVES TOWARDS FAR NORTHEAST IOWA OR SOUTHWEST WISCONSIN...THE NOSE OF THE LLJ WILL IMPINGE ON CENTRAL AND NORTHEAST WISCONSIN. OUTSTANDING MOISTURE TRANSPORT WILL ADVECT IN PWATS GREATER THAN 2 INCHES WHILE STRONG MID-LEVEL FGEN WILL BE FOCUSED ON THE NOSE OF THE LLJ. ELEVATED INSTABILITY WILL PEAK DURING THE EVENING HOURS...SO SOME POTENTIAL FOR SEVERE CONVECTION WITH DAMAGING WIND GUSTS TO REACH CENTRAL WISCONSIN ALONG THE LEADING EDGE OF ANY THUNDERSTORMS MOVING NORTHEAST OUT OF IOWA. BUT INSTABILITY RAPIDLY WANES AFTER MIDNIGHT...LEAVING HEAVY RAINFALL AS THE MAIN HAZARD. ALTHOUGH THERE REMAINS SOME UNCERTAINTY WITH THE TRACK OF THE SURFACE LOW...THE HEAVIEST RAINFALL SHOULD FALL ON THE NOSE OF THE LLJ WHICH IS PROJECTED TO PUSH ACROSS CENTRAL AND NORTHEAST WISCONSIN OVERNIGHT INTO WEDNESDAY MORNING. 1.5 TO 2.5 INCHES OF RAIN WITH LOCALLY HIGHER AMOUNTS ARE POSSIBLE OVER CENTRAL WISCONSIN BY MORNING. WEDNESDAY...LOW PRESSURE WILL TRACK TOWARDS THE COAST LINE OF EAST-CENTRAL OR NORTHEAST WISCONSIN BY 18Z WED. THE HEAVIEST OF RAIN WILL BE ONGOING ON THE NOSE OF THE LLJ OVER NORTHEAST WISCONSIN. LOOKING FOR THE SAME MAGNITUDE OF AMOUNTS IN THIS REGION COMPARED TO CENTRAL WISCONSIN...1.5 TO 2.5 INCHES WITH LOCALLY HIGHER AMOUNTS. THE HEAVY RAIN WILL PULL OUT WEDNESDAY AFTERNOON AS NORTHWEST WINDS BEHIND THE SYSTEM DRAWS IN MUCH COLDER AIR INTO NORTH-CENTRAL WISCONSIN. A WIDE RANGE OF HIGH TEMPERATURES WILL BE PRESENT TOMORROW...RANGING FROM THE MIDDLE 50S NORTH TO THE LOWER 70S SOUTHEAST. .LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY ISSUED AT 245 PM CDT TUE SEP 9 2014 COOLER TEMPERATURE TRENDS AND PCPN CHANCES WILL BE THE FOCUS DURING THIS PERIOD. REMAINING SHOWERS FROM THE STRONG WEDNESDAY SYSTEM WILL DEPART TO THE NORTHEAST BUT SMALL SHOWER CHANCES WILL LINGER INTO THURSDAY OVER THE NORTH DUE TO CAA INSTABILITY OVER LAKE SUPERIOR. BLUSTERY NORTH WINDS WILL BRING A FEEL OF FALL TO THE AREA. HIGH PRESSURE WILL REMAIN SETTLED OVER THE NORTHERN PLAINS THURSDAY NIGHT WITH SUBTLE CAA CONTINUING. SOME POTENTIAL OF FROST FRIDAY MORNING OVER THE NORTH BUT WILL DEPEND ON DIMINISHING WINDS AND CLOUDS. CLOUDS MAY ALREADY BE ON THE INCREASE WITH THE APPROACH OF A DEEP MID LEVEL TROUGH OR CLOSED UPPER LOW SYSTEM. THIS SYSTEM WILL BRING A CHANCE OF SHOWERS TO THE AREA WHICH WILL LINGER INTO SATURDAY MORNING. COOL HIGH PRESSURE WILL THEN BUILD INTO THE THE GREAT LAKES REGION FOR THE WEEKEND TO PROVIDE MORE CHANCES OF FROST...AND POSSIBLE HEADLINES. AGAIN WINDS MAY BE AN ISSUE SINCE THE CENTER OF THE HIGH SLIDES INTO CENTRAL ILLINOIS SATURDAY NIGHT. RETURN FLOW WILL BEGIN TO BRING MODERATING WARMER TEMPS INTO THE AREA SUNDAY FOLLOWED WITH ANOTHER CHANCE OF SHOWERS WITH A POSSIBLE FRONTAL SYSTEM FOR EARLY NEXT WEEK. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1000 PM CDT TUE SEP 9 2014 EXPECT CONDITIONS TO CONTINUE TO DETERIORATE OVERNIGHT AS LOW PRESSURE MOVES INTO THE STATE. ALREADY LOCAL IFR CIGS AND VSBYS IN FOG ALONG LAKE MICHIGAN. LARGE AREA OF SHOWERS AND THUNDERSTORMS MOVING NORTHEAST AHEAD OF LOW. LIFR CONDITIONS ARE LIKELY AT RHI AND AUW/CWA AND POSSIBLY GRB/ATW/MTW OVERNIGHT THROUGH WEDNESDAY MORNING. IMPROVING CONDITIONS SHOULD OCCUR WEDNESDAY AFTERNOON. && .HYDROLOGY... ISSUED AT 245 PM CDT TUE SEP 9 2014 WHILE A SOAKING RAIN OF 1.00 TO 1.50 IS EXPECTED FOR ALL LOCATIONS TONIGHT INTO WEDNESDAY...VERY CHALLENGING FORECAST WITH DETERMINING THE AXIS OF HEAVIER RAINFALL DUE TO THE TRACK OF THE SURFACE LOW. ECMWF TRACKS PLACES THE MAX OF 2-3 INCHES OVER CENTRAL TO NORTHEAST WISCONSIN...NAM MUCH FURTHER NORTH WHILE THE GEM AND MAV FOCUS OVER THE SOUTH HALF OF THE STATE INCLUDING BRUSHING PARTS OF EAST CENTRAL WISCONSIN. TO COMPLICATE THE SITUATION...RADAR TRENDS OVER THE CENTRAL PLAINS SHOWING SOME SPLIT IN THE RAIN REGIONS. THE SOUTHERN REGION OF HEAVY RAINFALL OVER SOUTHWEST IOWA IS THE PRIMARY REGION OF CONCERN AND WILL BE THE FOCUS OF LATER NIGHT HEADLINES. REGARDLESS...THE FLOOD WATCH WILL CONTINUE FOR THE ENTIRE AREA STARTING LATE THIS EVENING. && .GRB WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH THROUGH WEDNESDAY EVENING FOR WIZ005-010>013-018>022- 030-031-035>040-045-048>050-073-074. && $$ UPDATE.........JKL SHORT TERM.....MPC LONG TERM......TDH AVIATION.......JKL HYDROLOGY......TDH
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
945 PM CDT TUE SEP 9 2014 .UPDATE... WILL BE HOLDING ON TO FLASH FLOOD WATCH AS RAP FORECAST SOUNDINGS AROUND 4 AM SHOW EXTREMELY STRONG OMEGA THAT CROSSES THE CWA BETWEEN 08Z AND 15Z...PW/S IN THE 2 TO 2.2 INCH RANGE AND WARM CLOUD DEPTH OF 13K FT WITH A LOW-LEVEL JET AROUND 50 KTS NOSING INTO THE SW CORNER OF WI AROUND 06Z AHEAD OF RAPIDLY DEEPENING SYSTEM THAT ACCELERATES INTO WESTERN WI BY 12Z WED. SOME CONCERN ABOUT QPF AMOUNTS GIVEN INITIAL...MAINLY STRATIFORM PCPN MOVING INTO CWA NOW...BUT CANT IGNORE THE ROBUST LIFT AND MOISTURE MOVING IN AHEAD OF STRENGTHENING SYSTEM. WPC HAS QPF BULLSEYE SOUTH INTO NRN IL...WITH A LESSER SECONDARY DEFORMATION ZONE MAXIMA OVER THE ERN U.P./NRN LK MICHIGAN...WHILE LATEST NAM CLIPS FAR SRN WI WITH A 2 INCH MAX...AND A HIGHER DEFORMATION ZONE MAX THAT JUST MISSES TO THE NW. WILL ADJUST QPF A BIT BUT BASICALLY LEAVE AMOUNTS INTACT WITH THE POTENTIAL FOR HEAVY RAIN AFTER 06Z...AND PROBABLY CLOSER TO 09Z...THROUGH 12Z-15Z OVER THE CWA. && .AVIATION/06Z TAFS/... WHILE THERE MAY BE A FEW SPOTTY MVFR CIGS/VSBYS WITH STRATIFORM PCPN CROSSING CWA NOW...EXPECT VFR CONDITIONS TO NOT PERMANENTLY LOWER TO MVFR UNTIL SHOWERS AND STORMS MOVE IN AFTER 06Z AT KMSN AND AFTER 09Z AT EASTERN TAF SITES. WINDS AROUND 3K FT WILL JUMP TO AROUND 50 KTS BUT ENOUGH GRADIENT BELOW AS DEEP LOW CROSS SW TO NE ACROSS STATE FOR SURFACE WINDS TO BE STRONG ENOUGH TO NOT NEED LLWS IN TAFS. STRONG COLD ADVECTION BEHIND LOW WILL BRING IFR CIGS IN SPITE OF GUSTY WEST TO NORTHWEST WINDS THAT WILL SLOWLY LOWER AFTER 00Z AS LOW PULLS AWAY. .MARINE...SMALL CRAFT ADVISORY TIMES LOOK GOOD AND WILL BE KEPT. MARINE DENSE FOG FOR NRN ZONES MAY BE DROPPED EARLY IF INCREASING WINDS BREAK UP THE FOG...BUT EVEN WITH THE STRONGER WINDS...THE HIGHER DEW POINT AIR MOVING OVER THE COOLER WATERS OFF OF SHEBOYGAN AND PT WASHINGTON MAY KEEP ADVECTION FOG DENSE ENOUGH FOR HEADLINE TO CONTINUE TO EXPIRATION. && .PREV DISCUSSION... /ISSUED 220 PM CDT TUE SEP 9 2014/ TONIGHT AND WEDNESDAY - CONFIDENCE...MEDIUM LOW PRESSURE WILL CONTINUE TO INTENSIFY AS IT APPROACHES WI TONIGHT. IMPRESSIVELY STRONG 850 LLJ AVERAGING 55 TO 65 KNOTS WILL TAKE AIM ON SRN WI LATER TONIGHT. SOUTHWEST UPPER JET WILL ENHANCE UPPER DIVERGENCE. PRECIPITABLE WATER VALUES EXCEED 2 INCHES WITH BUFKIT SOUNDINGS SHOWING A MOIST COLUMN THROUGH AN APPRECIABLE DEPTH. STORM MOTIONS WILL BE ON THE HIGH SIDE BUT EXPECTING VERY EFFICIENT RAINFALL RATES ON THE ORDER OF 1-2 IN/HOUR AT TIMES. THERE ARE STILL SOME MODEL DIFFERENCES ON PLACEMENT OF FEATURES. THE MOST DIRECT BULLSEYE FOR SRN WI IS THE GFS WITH THE ECMWF KEYING ON THE NRN CWA. MEANWHILE THE GEM IS SKEWED FURTHER SOUTH INTO NRN IL WITH THE HEAVIER AXIS INTO SE WI. MEANWHILE THE NAM HAS HEAVIEST PRECIP WITH DEF ZONE PRECIP IN NW WI WITH A CONVECTIVE BAND INTO SRN WI. SO THIS ALL POINTS TO THE WATCH WE HAVE. IT IS JUST A WATCH AND THERE IS STILL SOME MODEL UNCERTAINTY ON EXACTLY HOW THIS WILL PLAY OUT. BUT GIVEN THE POTENTIAL LAID OUT BY THE MODELS FROM A PURELY QPF STANDPOINT THE WATCH IS CERTAINLY MERITED. THIS WILL IMPACT THE MORNING RUSH HOUR AS WELL. STILL CONCERN FOR SOME HEFTY WINDS WITH ANY STORM CELL AS THE STRONGER WINDS ALOFT GET TAPPED INTO AND BROUGHT DOWN TO THE SURFACE VIA DOWNWARD MOMENTUM TRANSFER/WET MICROBURST IDEA. EXPECTING THINGS TO WIND DOWN QUITE RAPIDLY LATE MORNING INTO EARLY AFTERNOON. LLJ WILL SHIFT EAST AND NW WINDS AND LLVL CAA WILL BEGIN IN THE WAKE OF THE FRONT. 2 METER TEMP PROGS SHOW RAPID DROPOFF IN SFC TEMPS DURG THE AFTN THOUGH MOS LESS PRONOUNCED ON THE COOL DOWN. EXPECT SOME POST-FRONTAL DROPOFF THOUGH. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...FORECAST CONFIDENCE IS HIGH. STRONG COLD/DRY AIR ADVECTION ARRIVES BY WEDNESDAY EVENING AND CONTINUES THROUGH THURSDAY. BRISK NORTHWEST WINDS WILL GRADUALLY DIMINISH AS THE GRADIENT RELAXES FOLLOWING THE RAPID DEPARTURE OF THE LOW. SKIES WILL GENERALLY REMAIN ON THE CLOUDIER SIDE WITH A NOISY FAST MID LEVEL FLOW KEEPING AT LEAST SOME MID AND HIGH LEVEL CLOUDS STREAMING IN HERE. THE CU RULE DOES SUPPORT DIURNAL CU ON THURSDAY. AN APPROACHING STRONG MID LEVEL SHORT WAVE WILL REALLY THICKEN UP THE CLOUDS BY LATE THURSDAY NIGHT. FRIDAY AND FRIDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM. A STRONG SHORT WAVE WILL TRACK ACROSS WISCONSIN FRIDAY INTO FRIDAY EVENING. THE ECMWF ACTUALLY CLOSES OFF A FEW H5 HEIGHT CONTOURS AS IT PUSHES ACROSS THE GREAT LAKES. THE GFS AND THE CANADIAN HAVE MORE OF AN OPEN TROF. AT THE SFC THE PATTERN REMAINS BENIGN WITH MOSTLY HIGH PRESSURE IN PLACE. THE ECMWF TRIES TO BRING AN INVERTED TROF UP ACROSS LAKE MICHIGAN/LOWER MICHIGAN...BUT IT IS THE STRONGEST OF THE MODELS WITH THIS SYSTEM. DESPITE THE QUIET LOWER LEVELS...THERE IS IMPRESSIVE MID LEVEL FRONTOGENESIS AND ENOUGH MOISTURE TO SUPPORT SOME SHOWERS FRIDAY INTO FRIDAY EVENING. SATURDAY AND SUNDAY...FORECAST CONFIDENCE IS HIGH. HIGH PRESSURE AND VERY CHILLY AIR WILL BE IN PLACE THIS WEEKEND. AT LEAST WE SHOULD SEE SOME SUNSHINE. LOOK FOR A SLIGHT MODERATION IN TEMPS BETWEEN SATURDAY AND SUNDAY. LOWS BOTH SATURDAY AND SUNDAY WILL BE DOWN IN THE 40S WITH SOME UPPER 30S POSSIBLE IN A FEW SPOTS. MONDAY...FORECAST CONFIDENCE IS MEDIUM. THE FAST ZONAL MID LEVEL FLOW WILL BRING ANOTHER SHORTWAVE IN HERE FOR MONDAY...POSSIBLY KICKING OFF A FEW SHOWERS. PRETTY MINOR STUFF AT THIS POINT. AVIATION/00Z TAFS/...LOW PRESSURE WILL CONTINUE TO STRENGTHEN AS IT RIDES NORTHEAST INTO LATER TONIGHT INTO WEDNESDAY MORNING. VERY HEAVY RAINFALL RATES WILL ALLOW FOR IFR CIGS/VSBYS AS RA/TSRA MOVE ACROSS...WITH THE MAIN WINDOW BETWEEN 06Z-16Z...WEST TO EAST ACROSS SRN WI. GUSTY SOUTH THEN SOUTHWEST WINDS WILL DEVELOP LATER THIS EVENING AHEAD OF THE LOW AND THEN SHIFT NORTHWEST AND BECOME GUSTY AFTER THE LOW MOVES EAST BY WEDNESDAY AFTERNOON. SOME POTENTIAL FOR LLWS IN THE 10-14Z TIME FRAME DUE TO PROXIMITY OF STRONGER WINDS ASSOCIATED WITH THE SOUTHERLY LOW LEVEL WIND MAX. MARINE...WINDS/WAVES WILL REACH SMALL CRAFT ADVISORY CONDITIONS LATE TONIGHT AND APPROACH GALE WARNING CRITERIA ON WEDNESDAY AND WEDNESDAY EVENING AS AN UNUSUALLY STRONG EARLY SEASON LOW INTENSIFIES OVER WISCONSIN WEDNESDAY. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH FROM 1 AM CDT WEDNESDAY THROUGH WEDNESDAY AFTERNOON FOR WIZ046-047-051-052-056>060-062>072. LM...SMALL CRAFT ADVISORY FROM 4 AM WEDNESDAY TO NOON CDT THURSDAY FOR LMZ643>646. DENSE FOG ADVISORY UNTIL 7 AM CDT WEDNESDAY FOR LMZ643-644. && $$ UPDATE...REM TONIGHT/WEDNESDAY AND AVIATION/MARINE...COLLAR WEDNESDAY NIGHT THROUGH TUESDAY...DAVIS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
704 PM CDT TUE SEP 9 2014 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND WEDNESDAY ISSUED AT 245 PM CDT TUE SEP 9 2014 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG COLD FRONT MOVING SOUTHEAST ACROSS NORTHERN MINNESOTA AND SOUTH DAKOTA...WHILE LOW PRESSURE IS EMERGING INTO WESTERN KANSAS. AN ISOLATED THUNDERSTORM DROPPED A QUARTER OF AN INCH OF RAIN OVER WAUSAU EARLIER THIS MORNING WITHIN A MODEST MOISTURE AXIS BUT DIMINISHED BY MIDDAY. OTHERWISE...NO OTHER CONVECTION HAS DEVELOPED SO FAR TODAY. THUNDERSTORM ACTIVITY CONTINUES TO EXPAND OVER NEBRASKA AND IOWA IN AN AREA OF MOISTURE CONVERGENCE AT 850MB. AS LOW PRESSURE MOVES EAST AND THE LLJ MATURES THIS EVENING...THIS AREA WILL DRAW ATTENTION FOR THE POTENTIAL OF SEVERE WEATHER AND HEAVY RAIN DOWNSTREAM OVER CENTRAL AND NORTHEAST WISCONSIN LATER TONIGHT. ANOTHER AREA OF RAIN CONTINUES TO DEVELOP OVER THE EASTERN DAKOTAS. AS THESE SYSTEMS MOVE EAST...SEVERE WEATHER AND HEAVY RAIN POTENTIAL ARE THE MAIN FORECAST CONCERNS. TONIGHT...FOLLOWED THE ECMWF AND SREF FOR THE DETAILS OF THIS FORECAST...WHICH IS PREFERRED BY HPC AND SUPPORTED BY THE ENSEMBLE MEANS. THESE MODELS SHOW THAT THE STRONG COLD FRONT OVER THE NORTHERN PLAINS WILL SAG SOUTH INTO NORTH-CENTRAL WISCONSIN THIS EVENING AS LOW PRESSURE TRACKS NORTHEAST ACROSS THE CENTRAL PLAINS. AHEAD OF THIS LOW...MID-LEVEL FLOW WILL BE BACKING WHILE INCREASING AT THE SAME TIME...LEADING TO INCREASING ISENTROPIC ASCENT IN THE PRESENCE OF MID-LEVEL LAPSE RATES BETWEEN 6-7 C/KM THROUGH THE EVENING. WEAK SHORTWAVE ENERGY AND UPPER DIVERGENCE WILL ALSO BE APPROACHING BY LATE IN THE EVENING. THIS ALL POINTS TO INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS FROM WEST TO EAST THROUGH THE EVENING. PRECIP MAY BE MORE OF THE SCATTERED VARIETY DURING THE EVENING...BUT THE MAIN SHOW LOOKS TO ARRIVE AFTER MIDNIGHT FROM THE SOUTHWEST. AS THE LOW MOVES TOWARDS FAR NORTHEAST IOWA OR SOUTHWEST WISCONSIN...THE NOSE OF THE LLJ WILL IMPINGE ON CENTRAL AND NORTHEAST WISCONSIN. OUTSTANDING MOISTURE TRANSPORT WILL ADVECT IN PWATS GREATER THAN 2 INCHES WHILE STRONG MID-LEVEL FGEN WILL BE FOCUSED ON THE NOSE OF THE LLJ. ELEVATED INSTABILITY WILL PEAK DURING THE EVENING HOURS...SO SOME POTENTIAL FOR SEVERE CONVECTION WITH DAMAGING WIND GUSTS TO REACH CENTRAL WISCONSIN ALONG THE LEADING EDGE OF ANY THUNDERSTORMS MOVING NORTHEAST OUT OF IOWA. BUT INSTABILITY RAPIDLY WANES AFTER MIDNIGHT...LEAVING HEAVY RAINFALL AS THE MAIN HAZARD. ALTHOUGH THERE REMAINS SOME UNCERTAINTY WITH THE TRACK OF THE SURFACE LOW...THE HEAVIEST RAINFALL SHOULD FALL ON THE NOSE OF THE LLJ WHICH IS PROJECTED TO PUSH ACROSS CENTRAL AND NORTHEAST WISCONSIN OVERNIGHT INTO WEDNESDAY MORNING. 1.5 TO 2.5 INCHES OF RAIN WITH LOCALLY HIGHER AMOUNTS ARE POSSIBLE OVER CENTRAL WISCONSIN BY MORNING. WEDNESDAY...LOW PRESSURE WILL TRACK TOWARDS THE COAST LINE OF EAST-CENTRAL OR NORTHEAST WISCONSIN BY 18Z WED. THE HEAVIEST OF RAIN WILL BE ONGOING ON THE NOSE OF THE LLJ OVER NORTHEAST WISCONSIN. LOOKING FOR THE SAME MAGNITUDE OF AMOUNTS IN THIS REGION COMPARED TO CENTRAL WISCONSIN...1.5 TO 2.5 INCHES WITH LOCALLY HIGHER AMOUNTS. THE HEAVY RAIN WILL PULL OUT WEDNESDAY AFTERNOON AS NORTHWEST WINDS BEHIND THE SYSTEM DRAWS IN MUCH COLDER AIR INTO NORTH-CENTRAL WISCONSIN. A WIDE RANGE OF HIGH TEMPERATURES WILL BE PRESENT TOMORROW...RANGING FROM THE MIDDLE 50S NORTH TO THE LOWER 70S SOUTHEAST. .LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY ISSUED AT 245 PM CDT TUE SEP 9 2014 COOLER TEMPERATURE TRENDS AND PCPN CHANCES WILL BE THE FOCUS DURING THIS PERIOD. REMAINING SHOWERS FROM THE STRONG WEDNESDAY SYSTEM WILL DEPART TO THE NORTHEAST BUT SMALL SHOWER CHANCES WILL LINGER INTO THURSDAY OVER THE NORTH DUE TO CAA INSTABILITY OVER LAKE SUPERIOR. BLUSTERY NORTH WINDS WILL BRING A FEEL OF FALL TO THE AREA. HIGH PRESSURE WILL REMAIN SETTLED OVER THE NORTHERN PLAINS THURSDAY NIGHT WITH SUBTLE CAA CONTINUING. SOME POTENTIAL OF FROST FRIDAY MORNING OVER THE NORTH BUT WILL DEPEND ON DIMINISHING WINDS AND CLOUDS. CLOUDS MAY ALREADY BE ON THE INCREASE WITH THE APPROACH OF A DEEP MID LEVEL TROUGH OR CLOSED UPPER LOW SYSTEM. THIS SYSTEM WILL BRING A CHANCE OF SHOWERS TO THE AREA WHICH WILL LINGER INTO SATURDAY MORNING. COOL HIGH PRESSURE WILL THEN BUILD INTO THE THE GREAT LAKES REGION FOR THE WEEKEND TO PROVIDE MORE CHANCES OF FROST...AND POSSIBLE HEADLINES. AGAIN WINDS MAY BE AN ISSUE SINCE THE CENTER OF THE HIGH SLIDES INTO CENTRAL ILLINOIS SATURDAY NIGHT. RETURN FLOW WILL BEGIN TO BRING MODERATING WARMER TEMPS INTO THE AREA SUNDAY FOLLOWED WITH ANOTHER CHANCE OF SHOWERS WITH A POSSIBLE FRONTAL SYSTEM FOR EARLY NEXT WEEK. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 701 PM CDT TUE SEP 9 2014 AS A STRONG COLD FRONT DROPS SOUTHWARD INTO NORTHERN WISCONSIN TONIGHT...LOW PRESSURE WILL BE LIFTING NORTHEAST ACROSS SOUTHWEST TO EAST-CENTRAL WISCONSIN WEDNESDAY MORNING. AHEAD OF THIS FRONT AND SURFACE LOW...EXPECT CONDITIONS TO DETERIORATE THROUGH THE NIGHT...STARTING OUT IN NORTH-CENTRAL AND CENTRAL WISCONSIN THIS EVENING...AND THEN REACHING NORTHEAST WISCONSIN OVERNIGHT. BEFORE RAIN MOVES IN...HOWEVER...LOCAL IFR CIGS AND VSBYS IN FOG ALONG LAKE MICHIGAN. A LARGE AREA OF SHOWERS AND THUNDERSTORMS SHOULD SURGE NORTHEAST AHEAD OF LOW OVERNIGHT INTO EARLY WEDNESDAY MORNING WHICH COULD PRODUCE STRONG GUSTY WINDS...IN ADDITION WIDESPREAD HEAVY RAIN. LIFR CONDITIONS ARE LIKELY AT RHI AND AUW/CWA AND POSSIBLY GRB/ATW/MTW OVERNIGHT THROUGH WEDNESDAY MORNING. IMPROVING CONDITIONS SHOULD OCCUR WEDNESDAY AFTERNOON. && .HYDROLOGY... ISSUED AT 245 PM CDT TUE SEP 9 2014 WHILE A SOAKING RAIN OF 1.00 TO 1.50 IS EXPECTED FOR ALL LOCATIONS TONIGHT INTO WEDNESDAY...VERY CHALLENGING FORECAST WITH DETERMINING THE AXIS OF HEAVIER RAINFALL DUE TO THE TRACK OF THE SURFACE LOW. ECMWF TRACKS PLACES THE MAX OF 2-3 INCHES OVER CENTRAL TO NORTHEAST WISCONSIN...NAM MUCH FURTHER NORTH WHILE THE GEM AND MAV FOCUS OVER THE SOUTH HALF OF THE STATE INCLUDING BRUSHING PARTS OF EAST CENTRAL WISCONSIN. TO COMPLICATE THE SITUATION...RADAR TRENDS OVER THE CENTRAL PLAINS SHOWING SOME SPLIT IN THE RAIN REGIONS. THE SOUTHERN REGION OF HEAVY RAINFALL OVER SOUTHWEST IOWA IS THE PRIMARY REGION OF CONCERN AND WILL BE THE FOCUS OF LATER NIGHT HEADLINES. REGARDLESS...THE FLOOD WATCH WILL CONTINUE FOR THE ENTIRE AREA STARTING LATE THIS EVENING. && .GRB WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH THROUGH WEDNESDAY EVENING FOR WIZ005-010>013-018>022- 030-031-035>040-045-048>050-073-074. && $$ SHORT TERM.....MPC LONG TERM......TDH AVIATION.......JKL HYDROLOGY......TDH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND TUESDAY ISSUED AT 251 PM CDT MON SEP 8 2014 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SHORTWAVE TROUGH MOVING EAST NORTHEAST OVER NORTHWEST WISCONSIN EARLY THIS AFTERNOON. IN THE DEFORMATION ZONE OF THIS SHORTWAVE...AN AREA OF LIGHT RAIN IS MOVING NORTHEAST FROM AMERY TO PHILLIPS. DRY AIR HAS IMPEDED ITS PROGRESS SO FAR TODAY...BUT SHOULD SEE ENOUGH FORCING FOR LIGHT RAIN TO MAKE ITS WAY ACROSS NORTH-CENTRAL WISCONSIN THIS AFTERNOON DESPITE HIGH CLOUD BASES. MOSTLY CLEAR CONDITIONS EXIST BEHIND THIS SHORTWAVE OVER THE DAKOTAS. THEN THERE IS A STRONG COLD FRONT MOVING SLOWLY SOUTHEAST ACROSS SOUTH-CENTRAL CANADA. TIMING OF PRECIP CHANCES TONIGHT AND THE POTENTIAL FOR THUNDERSTORMS ON TUESDAY ARE THE MAIN FORECAST CONCERNS. TONIGHT...THE SHORTWAVE WILL MOVE ACROSS THE FORECAST AREA DURING THE EVENING. LIGHT RAIN IN THE DEFORMATION ZONE WILL MOVE NORTHEAST ACROSS N-C WISCONSIN EARLY THIS EVENING AND INTO THE UPPER PENINSULA BY MID-EVENING. DESPITE DECENT MID-LEVEL LAPSE RATES...THE SHORTWAVE WILL OUTRUN THE MOISTURE AXIS BELOW 700MB...AND AM COUNTING ON THE DRY AIR BELOW THIS LEVEL TO KEEP DRY CONDITIONS IN PLACE ELSEWHERE. BEHIND THE SHORTWAVE...MID-LEVELS DRY OUT AS SUBSIDENCE ARRIVES...BUT MODELS ALSO PROJECT AN INCREASE OF LOW LEVEL MOISTURE FROM THE CENTRAL PLAINS. BASED ON SATELLITE IMAGERY...THIS LOOKS OVERDONE AND PROGGED SOUNDINGS CONTINUE TO LOOK DRY ABOVE 850MB OVERNIGHT. WILL BACK OFF ON THE CLOUD COVER AS WELL AS PRECIP CHANCES. LOWS MAINLY IN THE 50S. TUESDAY...AS LOW PRESSURE EMERGES INTO THE CENTRAL PLAINS...A SHALLOW COLD FRONT WILL DROP SOUTHEAST INTO NORTH-CENTRAL WISCONSIN AND THE WESTERN UPPER PENINSULA DURING THE AFTERNOON. AHEAD OF THE FRONT...WEAK THETAE ADVECTION WILL BE ONGOING DURING THE MORNING...BUT PROGGED SOUNDINGS CONTINUE TO LOOK DRY ABOVE 850MB. WILL MOST LIKELY NEED TO WAIT FOR DAYTIME DESTABILIZATION TO TAKE PLACE FOR THE CHANCE OF SHOWERS AND THUNDERSTORMS TO OCCUR...STARTING EARLY AFTERNOON. BY MID-AFTERNOON...LOW LEVEL MOISTURE AXIS AND FORCING ALONG THE FRONT SHOULD IMPROVE THUNDERSTORM CHANCES. ML CAPES AHEAD OF THE BOUNDARY REACH UP TO 1200 J/KG WITH 0-6KM BULK SHEARS OF 20-25 KTS. CANNOT FIND MUCH OF A CAP BY 21Z...SO THINKING ISOLATED TO LOW END SCT SHOWERS AND STORMS WILL BE POSSIBLE. COULD SEE AN ISOLATED PULSE SEVERE THREAT DEVELOP IF INSTABILITY REACHES ITS POTENTIAL. HIGHS IN THE MIDDLE TO UPPER 70S. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY ISSUED AT 251 PM CDT MON SEP 8 2014 PRIMARY FOCUS DURING THIS PERIOD IS THE STRONG STORM SYSTEM TO IMPACT THE REGION THROUGH MID WEEK. STRONG CONVERGENCE WITH A DEEPENING SURFACE LOW AND H850 LOW TRACKING OVER THE STATE LATE TUESDAY INTO WEDNESDAY COMBINED WITH PWATS CLIMBING TO A VERY MOIST 1.50 TO 2.00 INCHES WILL LIKELY PRODUCE A SWATH OF HEAVY RAIN STARTING TUESDAY EVENING AND CONTINUE INTO WEDNESDAY AFTERNOON BEFORE GRADUALLY DIMINISHING FROM SOUTHWEST TO NORTHEAST. JUST ABOUT ALL MAIN STEM RIVERS ARE RUNNING HIGH AND ANTICIPATED AMOUNTS WOULD LIKELY RAISE LEVELS TO FLOOD STAGE. THE POTENTIAL OF A WIDESPREAD 1.50 TO AS HIGH AS 3.00 INCHES CONTINUES TO INCREASE. LOCALLY HIGHER RAINFALL AMOUNTS DUE TO STORMS COULD INCREASE THE IMPACTS OF THE FLOODING ALONG THE RIVERS AS WELL AS FOR URBAN AREAS. EVEN THOUGH THERE IS A FLASH FLOOD POTENTIAL...WILL GO WITH THE FLOOD WATCH VARIETY FOR NOW DUE TO THE HIGHER POTENTIAL OF THE RIVER FLOODING. MUCH COOLER TEMPERATURES WITH A SHOT OF BLUSTERY FALL WINDS WILL POUR INTO THE AREA FOR THE REST OF THE WEEK. MINOR PRECIP CHANCES WILL CONTINUE FOR THE REMAINDER OF THE WEEK AS A TROUGH OF LOW PRESSURE SETTLES OVER THE AREA. COOLER DRIER AIR REMAINS OVER THE WEEKEND WITH THE LIKELY CHANCE OF THE FIRST FROST OR FREEZE HEADLINE OF THE SEASON FOR THE NORTHERN PORTION OF THE FORECAST AREA. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1208 PM CDT MON SEP 8 2014 A WEAK DISTURBANCE WILL MOVE ACROSS THE REGION THIS AFTERNOON AND EVENING AND GENERATE LIGHT SHOWERS AND SPRINKLES...MAINLY OVER NORTHWEST WISCONSIN. PLENTY OF DRY AIR CURRENTLY RESIDES ACROSS THE REGION...BUT A FEW SHOWERS COULD SURVIVE THE TRIP INTO NORTH-CENTRAL WISCONSIN THIS AFTERNOON. CONFIDENCE IS TOO LOW TO INCLUDE IN THE RHI TAF...AND FLIGHT CATEGORIES SHOULD REMAIN IN THE VFR RANGE REGARDLESS. ONCE THIS DISTURBANCE EXITS LATE IN THE EVENING...MODELS DEPICT LOW LEVEL MOISTURE SURGING NORTHEAST THAT COULD CREATE BKN MVFR CLOUDS LATE TONIGHT OVER NORTH-CENTRAL WISCONSIN. THE MODELS APPEAR TO BE OVERDOING THE MOISTURE...HOWEVER...AND CONFIDENCE IS LOW AGAIN THAT WE WILL SEE MVFR CIGS DEVELOP. LEFT A SCT MENTION TO INDICATE THAT THERE MAY BE LOW CIGS AROUND LATE TONIGHT. IF CLOUDS DO NOT FORM...VFR CONDITIONS WILL PREVAIL FOR THE DURATION OF THE FORECAST. && .MARINE... ISSUED AT 251 PM CDT MON SEP 8 2014 GUSTY SOUTHEAST/SOUTH WINDS MAY DEVELOP WEDNESDAY ACROSS PORTIONS OF THE MARINE AREA DEPENDING ON TRACK OF THE LOW PRESSURE SYSTEM. ONCE THE SYSTEM MOVES EAST OF THE AREA... GALE FORCE GUSTS ARE POSSIBLE WEDNESDAY NIGHT INTO THURSDAY. WINDS AND WAVES WILL GRADUALLY SUBSIDE THURSDAY AFTERNOON AND EVENING. && .HYDROLOGY... ISSUED AT 251 PM CDT MON SEP 8 2014 WILL ISSUE A FLOOD WATCH FOR TUESDAY NIGHT INTO WEDNESDAY IN ANTICIPATION FOR A WIDESPREAD 1.50 TO NEARLY 3 INCH AMOUNTS IN A 24 HOUR PERIOD. THE WATCH WILL ALSO INCLUDE THE AREA WHICH RECEIVED HEAVY RAIN LAST WEEK AND WHERE RIVER LEVELS AND STREAMS REMAIN QUITE HIGH. SHOULD NOTE THAT EVEN THOUGH THE HEAVY RAIN WILL NOT REACH THE AREA UNTIL LATER TUESDAY EVENING...MINOR FLOODING MAY ACTUALLY START TUESDAY DUE TO HYDRO OPERATIONS RELEASING WATER EARLY IN ADVANCE OF THE HEAVY RAIN. EVEN THOUGH THE HEAVY RAINFALL WILL BE ENDING WEDNESDAY AFTERNOON...RUNOFF EFFECTS INTO AREA RIVES WILL BE ON THE INCREASE WEDNESDAY EVENING INTO THURSDAY AND IF THE SCENARIO PANS OUT...WARNINGS WILL PROBABLY BE GOING INTO AFFECT. && .GRB WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY EVENING FOR WIZ005-010>013-018>022-030-031-035>040-073-074. && $$ SHORT TERM.....MPC LONG TERM......TDH AVIATION.......MPC MARINE.........TDH HYDROLOGY......TDH
AREA FORECAST DISCUSSION
NWS TAUNTON MA
401 AM EDT WED SEP 10 2014 .SYNOPSIS... WEAK LOW PRESSURE PASSING SE OF NEW ENGLAND MAY BRING A FEW SHOWERS TO THE ISLANDS TODAY...OTHERWISE DRY WEATHER WILL PREVAIL TODAY. A COLD FRONT WILL SWING ACROSS THE REGION LATE THURSDAY AND EARLY FRIDAY...THEN STALL JUST OFFSHORE. A DISTURBANCE MOVING ALONG THIS FRONT SATURDAY MAY COME CLOSE ENOUGH TO RESULT IN SHOWERS. HIGH PRESSURE RETURNS WITH DRY AND COOLER WEATHER SUNDAY INTO TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 320 AM UPDATE... MAIN BATCH OF SHOWERS REMAINS SE OF NANTUCKET AND EXPECT MOST OF IT TO REMAIN OFFSHORE TODAY. MODELS SEEM TO BE STRUGGLING WITH HOW CLOSE THESE SHOWERS GET TO SE NEW ENGLAND...BUT HRRR LOOKS REASONABLE IN GRAZING NANTUCKET THROUGH MID MORNING. DRY AIR AT MID LEVELS PER 00Z CHATHAM SOUNDING WILL PREVENT MUCH OF THIS FROM REACHING GROUND...IN FACT WE MAY JUST END UP WITH FEW SPRINKLES ON ISLANDS AND OUTER CAPE. LOW CLOUDS AND PATCHY FOG WILL PREVAIL ELSEWHERE THROUGH DAYBREAK DUE TO LIGHT ONSHORE FLOW...BUT WILL BREAK AFTER SUNRISE AND GIVE WAY TO PARTLY TO MOSTLY SUNNY SKIES. CONTINUED ONSHORE FLOW WILL KEEP HIGHS NEAR AVERAGE FOR MOST PART...MAINLY IN 70S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... EXPECT A RETURN OF LOW CLOUDS/FOG TONIGHT WHICH SHOULD BE MORE WIDESPREAD AS LOWER LEVELS MOISTEN WITH E/SE FLOW. MAY SEE AREAS OF DENSE FOG ALONG IMMEDIATE COAST. OTHERWISE SURFACE RIDGE KEEPS US DRY ASIDE FROM SPOTTY DRIZZLE. COLD FRONT APPROACHES NEW ENGLAND THU BUT SHOULD REMAIN TO OUR W. FLOW TURNS MORE S/SW IN ADVANCE OF FRONT WHICH WILL HELP SCOUR OUT LOW CLOUDS/FOG IN THE MORNING...EXCEPT AROUND S COAST...CAPE COD AND ISLANDS WHERE IT MAY PERSIST INTO AFTERNOON. INSTABILITY LOOKS MARGINAL AND MID LEVEL LAPSE RATES ARE WEAK... BUT ENOUGH TO INCLUDE MENTION OF THUNDER AHEAD OF FRONT. BETTER CHANCES ACROSS INTERIOR WHERE S FLOW OFF OCEAN IS LESS OF STABILIZING FACTOR. MODELS CONTINUE TO SHOW PLENTY OF MOISTURE AVAILABLE WITH PRECIPITABLE WATER VALUES NEAR 2 INCHES /+2 TO +3 STANDARD DEVIATION/...SO LOCALLY HEAVY RAINFALL CAN BE EXPECTED. HIGHS SHOULD REACH 70S AND LOWER 80S...AND IT WILL FEEL MORE SUMMERLIKE AS DEWPOINTS CLIMB WELL INTO 60S. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HIGHLIGHTS... * SCATTERED SHOWERS/ISOLATED T-STORMS THU PM INTO EARLY FRI * SLIGHT CHANGE FOR SHOWERS SAT PM/SUN * A TASTE OF AUTUMN TEMPERATURES NEXT WEEK OVERVIEW... LATEST MODEL AND ENSEMBLE GUIDANCE OVERALL SEEMS TO OFFER FAIRLY REASONABLE LARGER SCALE PATTERN EVOLUTION CONTINUITY. AN AMPLIFYING ERN PAC TROUGH AND WEST COAST RIDGE DRIFTING INTO WRN NOAM WILL SUPPORT MEAN MID-UPPER LEVEL TROUGHING OVER THE ERN HALF OF NOAM. THIS PATTERN...MORE TYPICAL OF THE COLD SEASON THAN LATE SUMMER OR EARLY FALL...SHOULD YIELD BELOW TO MUCH BELOW NORMAL TEMPS OVER MOST OF THE ERN 2/3 OF THE CONUS. HOWEVER...DETERMINISTIC MODEL RUNS FEATURE TOO MUCH INCONSISTENCY. SEVERAL RIPPLES WILL MOVE THROUGH THE FLOW THROUGH THE PERIOD WITH THE FIRST ONE BRINGING A COLD FRONT ON THURSDAY NIGHT/FRI MORNING. ANOTHER SHORTWAVE WILL PASS SAT/SAT NIGHT. THIS ONE CAUSES MORE UNCERTAINTY AS THE GFS IS HAVING CONVECTIVE FEEDBACK AND IS CREATING A 1-2 INCH BULLS-EYE OVER THE REGION...IN RETROSPECT THE EC IS PRODUCING VERY LIGHT QPF. LASTLY ANOTHER WAVE WILL MOVE TROUGH THE FLOW MONDAY NIGHT/TUESDAY. OVERALL HAVE MODERATE CONFIDENCE IN THE FORECAST AS THERE IS TO MUCH SPREAD BETWEEN THE DETERMINISTIC AND ENSEMBLE FORECASTS ESP IN SPECIFIC DETAILS IN THE FORECAST. DETAILS... THURSDAY NIGHT INTO FRIDAY... THE FOCUS IS ON A STRONG COLD FRONT THAT WILL PUSH ACROSS THE REGION THURSDAY NIGHT INTO FRIDAY MORNING. BOTH DETERMINISTIC AND ENSEMBLES KEEP THE INSTABILITY VALUES VERY LOW BUT BECAUSE OF THE STRENGTH OF THIS FRONT HAVE KEPT ISO MENTIONING OF THUNDER FOR THURSDAY. TIMED THE THUNDER POTENTIAL WITH THE BETTER K-VALUES AND LI. PRECIPITABLE WATERS INCREASE CONSIDERABLY...CLOSE TO 2-3 INCHES...WITH A STRENGTHENING SOUTHERLY FLOW. SOME OF THESE STORMS MAY PRODUCE HEAVY RAIN...WITH AN ISOLD FLASH FLOOD THREAT PRIMARILY IN URBANIZED AREAS. THEREFORE ALSO INCLUDED HEAVY RAIN WORDING FOR ANY THUNDERSTORM POTENTIAL. HIGH PRESSURE WILL QUICKLY SWING INTO THE AREA BY FRIDAY ALLOWING FOR THE DAY TO DRY OUT AND TEMPS TO REACH NEAR NORMAL. SATURDAY TO SATURDAY NIGHT... HIGH PRESSURE WILL BEGIN TO LIFT NORTHWARD ALLOWING FOR EASTERLY FLOW ON SATURDAY. BY THE LATE AFTERNOON/EVENING HOURS A COLD FRONT WILL PASS THROUGH REGION BRINGING ANOTHER CHANCE OF THUNDERSTORMS. AS MENTIONED BEFORE...THERE IS SIGNIFICANT DIFFERENCE BETWEEN THE DETERMINISTIC GUIDANCE WITH THE GFS PRODUCING A 1-2 INCH BULLS-EYE. WHILE THE EC IS DEVELOPING LIGHT QPF. APPEARS THE GFS IS RECEIVING CONVECTIVE FEEDBACK BUT BECAUSE BOTH ARE TRENDING TO MOVE PRECIP...HAVE INCREASED THE POTENTIAL TO CHANCE POP. SUNDAY INTO NEXT WEEKEND... A MODIFIED CANADIAN HIGH WILL THEN BUILD IN THROUGH EARLY NEXT WEEK BEFORE ANOTHER FRONTAL SYSTEM POSSIBLY IMPACTS THE AREA AROUND TUES OF NEXT WEEK. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. MODERATE CONFIDENCE THROUGH THU. AREAS OF MVFR/IFR CIGS/VSBYS THROUGH 12Z WITH BRIEF SHOWER/ SPRINKLE POSSIBLE NEAR NANTUCKET AND VINEYARD. CONDITIONS IMPROVE TO VFR AFTER 12Z FROM W TO E BUT MVFR CIGS MAY LINGER INTO EARLY AFTERNOON NEAR S COAST...CAPE COD AND ISLANDS. CIGS/VSBYS LOWER AGAIN TONIGHT DUE TO PERSISTENT ONSHORE FLOW... THIS TIME TO IFR/LIFR ACROSS MUCH OF REGION. CONDITIONS SLOWLY IMPROVE TO VFR AGAIN THU MORNING...LAST ACROSS CAPE COD AND ISLANDS THU AFTERNOON...BUT SCATTERED SHOWERS/THUNDERSTORMS POSSIBLE ACROSS INTERIOR AFTER 18Z. MAY REACH BOS/PVD BY 22Z. KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS BUT LOWER CONFIDENCE ON EXACT TIMING. KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS BUT LOWER CONFIDENCE ON EXACT TIMING. OUTLOOK...FRIDAY THROUGH SUNDAY...MODERATE CONFIDENCE. FRIDAY...A PERIOD OF MVFR/IFR CONDITIONS POSSIBLE EARLY FRIDAY IN SCATTERED SHOWERS/ISOLATED THUNDERSTORMS AS A COLD FRONT SWEEPS THROUGH. OTHERWISE...VFR CONDITIONS EXPECTED FOR A GOOD PORTION OF THIS PERIOD. SATURDAY...LOW CONFIDENCE. MAINLY VFR. ONSHORE FLOW COULD ALSO RESULT IN IFR STRATUS AND FOG ACROSS PORTIONS OF THE EAST COAST...PARTICULARLY CAPE COD AND THE ISLANDS. SUNDAY...MODERATE CONFIDENCE. MAINLY VFR. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH THU. SCA REMAINS POSTED FOR OUTER WATERS MAINLY DUE TO 5-6 FT SEAS TODAY THROUGH THU. E/NE WINDS GRADUALLY SUBSIDE TODAY AS LOW PRESSURE PASSES WELL SE OF NEW ENGLAND...THEN S/SW WINDS DEVELOP THU AS COLD FRONT APPROACHES FROM GREAT LAKES. MAIN CONCERN IS PATCHY DENSE FOG TONIGHT INTO THU...ESPECIALLY ON S COASTAL WATERS. OUTLOOK...FRIDAY THROUGH SUNDAY...MODERATE CONFIDENCE. FRIDAY...MODERATE CONFIDENCE. A ROUND OF SCATTERED SHOWERS AND PERHAPS ISOLATED THUNDERSTORMS ARE EXPECTED EARLY FRIDAY MORNING AS A COLD FRONT PASSES THROUGH. WINDS WILL MAY REACH ABOVE 25 KT BEHIND THIS FRONT ALLOWING FOR SEAS TO APPROACH 5 FT AT TIMES ACROSS THE OUTER COASTAL WATERS. SMALL CRAFT ADVISORIES MAY BE NEEDED. SATURDAY...LOW CONFIDENCE. TIGHTENING PRESSURE GRADIENT AND APPROACHING COLD FRONT WILL HELP KEEP SEAS AND WINDS UP ON SATURDAY. SMALL CRAFT ADV MAY BE NEEDED. SUNDAY...STRONG COLD FRONT WILL PASS OVER THE WATERS IN THE MORNING. COLD AIR ALOFT WILL INCREASE SEAS AND WIND GUSTS ON SUNDAY LEADING TO THE POTENTIAL OF A SMALL CRAFT ADV. && .TIDES/COASTAL FLOODING... LAST HIGH TIDE JUST BEFORE MIDNIGHT PRODUCED 0.2 FT SURGE ALONG E MA COAST. SUBSEQUENT HIGH TIDES TODAY INTO THU ARE A BIT LOWER AND SURGE WILL BE MINIMAL...THEREFORE NO IMPACT IS EXPECTED. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ250- 254>256. && $$ SYNOPSIS...DUNTEN/JWD NEAR TERM...JWD SHORT TERM...JWD LONG TERM...DUNTEN AVIATION...DUNTEN/JWD MARINE...DUNTEN/JWD TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
321 AM EDT WED SEP 10 2014 .SYNOPSIS... WEAK LOW PRESSURE PASSING SE OF NEW ENGLAND MAY BRING A FEW SHOWERS TO THE ISLANDS TODAY...OTHERWISE DRY WEATHER WILL PREVAIL TODAY. A COLD FRONT WILL SWING ACROSS THE REGION LATE THURSDAY AND EARLY FRIDAY...THEN STALL JUST OFFSHORE. A DISTURBANCE MOVING ALONG THIS FRONT SATURDAY MAY COME CLOSE ENOUGH TO RESULT IN SHOWERS. HIGH PRESSURE RETURNS WITH DRY AND COOLER WEATHER SUNDAY INTO TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 320 AM UPDATE... MAIN BATCH OF SHOWERS REMAINS SE OF NANTUCKET AND EXPECT MOST OF IT TO REMAIN OFFSHORE TODAY. MODELS SEEM TO BE STRUGGLING WITH HOW CLOSE THESE SHOWERS GET TO SE NEW ENGLAND...BUT HRRR LOOKS REASONABLE IN GRAZING NANTUCKET THROUGH MID MORNING. DRY AIR AT MID LEVELS PER 00Z CHATHAM SOUNDING WILL PREVENT MUCH OF THIS FROM REACHING GROUND...IN FACT WE MAY JUST END UP WITH FEW SPRINKLES ON ISLANDS AND OUTER CAPE. LOW CLOUDS AND PATCHY FOG WILL PREVAIL ELSEWHERE THROUGH DAYBREAK DUE TO LIGHT ONSHORE FLOW...BUT WILL BREAK AFTER SUNRISE AND GIVE WAY TO PARTLY TO MOSTLY SUNNY SKIES. CONTINUED ONSHORE FLOW WILL KEEP HIGHS NEAR AVERAGE FOR MOST PART...MAINLY IN 70S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... EXPECT A RETURN OF LOW CLOUDS/FOG TONIGHT WHICH SHOULD BE MORE WIDESPREAD AS LOWER LEVELS MOISTEN WITH E/SE FLOW. MAY SEE AREAS OF DENSE FOG ALONG IMMEDIATE COAST. OTHERWISE SURFACE RIDGE KEEPS US DRY ASIDE FROM SPOTTY DRIZZLE. COLD FRONT APPROACHES NEW ENGLAND THU BUT SHOULD REMAIN TO OUR W. FLOW TURNS MORE S/SW IN ADVANCE OF FRONT WHICH WILL HELP SCOUR OUT LOW CLOUDS/FOG IN THE MORNING...EXCEPT AROUND S COAST...CAPE COD AND ISLANDS WHERE IT MAY PERSIST INTO AFTERNOON. INSTABILITY LOOKS MARGINAL AND MID LEVEL LAPSE RATES ARE WEAK... BUT ENOUGH TO INCLUDE MENTION OF THUNDER AHEAD OF FRONT. BETTER CHANCES ACROSS INTERIOR WHERE S FLOW OFF OCEAN IS LESS OF STABILIZING FACTOR. MODELS CONTINUE TO SHOW PLENTY OF MOISTURE AVAILABLE WITH PRECIPITABLE WATER VALUES NEAR 2 INCHES /+2 TO +3 STANDARD DEVIATION/...SO LOCALLY HEAVY RAINFALL CAN BE EXPECTED. HIGHS SHOULD REACH 70S AND LOWER 80S...AND IT WILL FEEL MORE SUMMERLIKE AS DEWPOINTS CLIMB WELL INTO 60S. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HIGHLIGHTS... * SCATTERED SHOWERS/ISOLATED T-STORMS THU PM INTO EARLY FRI * SLIGHT CHANGE FOR SHOWERS SAT PM/SUN * A TASTE OF AUTUMN TEMPERATURES NEXT WEEK OVERVIEW... BUILDING UPPER RIDGE OVER THE NE PACIFIC AND WESTERN CANADA...AS WELL AS MORE MODEST RIDGING OVER THE MARITIMES...WILL SUPPORT DEEP TROUGHING OVER THE CENTRAL CONUS LATE THIS WEEK. THIS DEEP TROUGH WILL PUSH A FRONT THROUGH OUR REGION BY LATE THU INTO FRI. OVERALL THE LONGWAVE PREDICTABILITY REMAINS BETTER THAN AVERAGE DESPITE THIS AMPLIFIED PATTERN. HOWEVER...DETERMINISTIC MODELS STILL FEATURE TOO MUCH INCONSISTENCY FROM RUN TO RUN TO BE CERTAIN OF THE DETAILS. THOUGH THE INITIAL TROUGH LIFTS THROUGH THE GREAT LAKES AND NORTHEAST INTO SOUTHEAST CANADA THIS WEEKEND...ENSEMBLES STILL SUPPORT THE POSSIBILITY OF A MORE PERSISTENT LONGWAVE RIDGE/TROUGH PATTERN....WITH SOUTHERN NEW ENGLAND CONTENDING MORE WITH A MID LEVEL TROUGH. THE MAIN QUESTION REMAINS HOW WAVY AND CLOSE TO THE COAST A COLD FRONT WILL REMAIN FRIDAY INTO SATURDAY. THIS WILL ULTIMATELY DETERMINE THE AMOUNT/LOCATION OF ADDITIONAL/OVERRUNNING PRECIPITATION. ENSEMBLE MEANS SUGGEST THE MAIN AXIS TO REMAIN JUST OFFSHORE...BUT A CLOSER POSITION IN SOME OF THE INDIVIDUAL MEMBERS SEEMS MORE CONSISTENT WITH SUCH AN AMPLIFIED PATTERN ALOFT. CONTINUE TO BE ON THE OPTIMISTIC SIDE AND KEPT A PORTION OF THIS WEEKEND DRY FOR NOW...MAINLY SUNDAY. OVERALL HAVE MODERATE CONFIDENCE IN THE FORECAST AS THERE IS TOO MUCH SPREAD BETWEEN THE DETERMINISTIC AND ENSEMBLE FORECASTS. DETAILS... THURSDAY INTO FRIDAY... FOCUS IS ON A STRONG COLD FRONT THAT WILL PUSH ACROSS THE REGION SOMETIME THURSDAY INTO FRIDAY. BOTH DETERMINISTIC AND ENSEMBLES KEEP INSTABILITY VERY LOW. THERE IS DECENT SHEAR IN THE LOWER LEVELS THOUGH. BECAUSE OF THE STRENGTH OF THIS FRONT AND THE SHEAR...KEPT A MENTION OF ISOLATED TO SCATTERED THUNDERSTORMS IN THE FORECAST. THERE COULD BE SOME HEAVY RAIN WITH THIS FRONT...BUT THE BEST DYNAMICS AND CONDITIONS WILL BE TO THE WEST OF OUR REGION. THIS FRONT WILL MAINLY PUSH THROUGH OVERNIGHT THURSDAY...THEN MOVE FARTHER OFFSHORE FRIDAY MORNING. ALTHOUGH THERE IS STILL SOME UNCERTAINTY ON TIMING AND HOW FAR OFFSHORE THIS FRONT WILL GO. THIS WEEKEND... ONCE AGAIN THIS FORECAST IS DEPENDENT ON HOW FAR OFFSHORE THE FRONT WILL GET TOO. 09/12Z GUIDANCE KEEPS THE FRONT FAR ENOUGH OFFSHORE...ALLOWING FOR A PORTION OF THIS WEEKEND TO BE DRY. HOWEVER MOST OF THE 09/12Z GUIDANCE ALSO SWINGS A WEAK COLD FRONT THROUGH THE GREAT LAKES INTO SOUTHERN NEW ENGLAND LATE SATURDAY INTO SATURDAY NIGHT. THIS COULD POTENTIALLY PRODUCE SOME LIGHT RAINFALL DURING THIS TIME. ONE THING TO WATCH IS THE CONTINUOUS EASTERLY FLOW OFF THE WATERS. THIS MAY KEEP FOG/LOW CLOUDS ACROSS THE EASTERN HALF OF THE REGION. THIS FORECAST IS STILL SEVERAL DAYS OUT...SO WILL CONTINUE TO FINE TUNE IT AS THIS WEEK PROGRESSES. EARLY NEXT WEEK... HIGH PRESSURE ARRIVES WITH A FALL-LIKE AIRMASS. 09/12Z GFS IS MUCH MORE AGGRESSIVE THAN THE ECMWF IN SWINGING A MID LEVEL SHORTWAVE THROUGH OUR REGION SOMETIME MONDAY INTO TUESDAY. BASED ON THE PATTERN THOUGH...AM THINKING MOSTLY DRY WEATHER WITH JUST AN INCREASE IN CLOUDS AT THIS TIME. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. MODERATE CONFIDENCE THROUGH THU. AREAS OF MVFR/IFR CIGS/VSBYS THROUGH 12Z WITH BRIEF SHOWER/ SPRINKLE POSSIBLE NEAR NANTUCKET AND VINEYARD. CONDITIONS IMPROVE TO VFR AFTER 12Z FROM W TO E BUT MVFR CIGS MAY LINGER INTO EARLY AFTERNOON NEAR S COAST...CAPE COD AND ISLANDS. CIGS/VSBYS LOWER AGAIN TONIGHT DUE TO PERSISTENT ONSHORE FLOW... THIS TIME TO IFR/LIFR ACROSS MUCH OF REGION. CONDITIONS SLOWLY IMPROVE TO VFR AGAIN THU MORNING...LAST ACROSS CAPE COD AND ISLANDS THU AFTERNOON...BUT SCATTERED SHOWERS/THUNDERSTORMS POSSIBLE ACROSS INTERIOR AFTER 18Z. MAY REACH BOS/PVD BY 22Z. KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS BUT LOWER CONFIDENCE ON EXACT TIMING. KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS BUT LOWER CONFIDENCE ON EXACT TIMING. OUTLOOK...FRIDAY THROUGH SUNDAY...MODERATE CONFIDENCE. FRIDAY...A PERIOD OF MVFR/IFR CONDITIONS POSSIBLE EARLY FRIDAY IN SCATTERED SHOWERS/ISOLATED THUNDERSTORMS AS A COLD FRONT SWEEPS THROUGH. THERE MAY ALSO BE SOME LOWER CLOUDS AND FOG PATCHES AT TIMES. OTHERWISE...VFR CONDITIONS EXPECTED FOR A GOOD PORTION OF THIS PERIOD. SATURDAY...LOW CONFIDENCE. MAINLY VFR. ONSHORE FLOW COULD ALSO RESULT IN IFR STRATUS AND FOG ACROSS PORTIONS OF THE EAST COAST...PARTICULARLY CAPE COD AND THE ISLANDS. SUNDAY...MODERATE CONFIDENCE. MAINLY VFR. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH THU. SCA REMAINS POSTED FOR OUTER WATERS MAINLY DUE TO 5-6 FT SEAS TODAY THROUGH THU. E/NE WINDS GRADUALLY SUBSIDE TODAY AS LOW PRESSURE PASSES WELL SE OF NEW ENGLAND...THEN S/SW WINDS DEVELOP THU AS COLD FRONT APPROACHES FROM GREAT LAKES. MAIN CONCERN IS PATCHY DENSE FOG TONIGHT INTO THU...ESPECIALLY ON S COASTAL WATERS. OUTLOOK...FRIDAY THROUGH SUNDAY...MODERATE CONFIDENCE. FRIDAY...MODERATE CONFIDENCE. WINDS WILL MAY REACH ABOVE 25 KT BEHIND COLD FRONT. A ROUND OF SCATTERED SHOWERS AND PERHAPS ISOLATED THUNDERSTORMS ARE EXPECTED THURSDAY NIGHT INTO EARLY FRIDAY. SEAS COULD APPROACH 5 FT AT TIMES ACROSS THE OUTER COASTAL WATERS. SMALL CRAFT ADVISORIES MAY BE NEEDED. SATURDAY...LOW CONFIDENCE. SEAS SHOULD SUBSIDE BELOW 5 FT AND EASTERLY WINDS SHOULD DIMINISH BELOW 20 KTS. SUNDAY...RELATIVELY TRANQUIL WINDS AND SEAS EXPECTED. OUTLOOK...THURSDAY THROUGH SUNDAY...MODERATE CONFIDENCE. THURSDAY AND FRIDAY...MODERATE CONFIDENCE. EASTERLY FLOW SWITCHES TO THE SOUTHWEST AHEAD OF AN APPROACHING COLD FRONT. WINDS WILL MAY REACH ABOVE 25 KT ON THE BACKSIDE OF THIS FRONT. A ROUND OF SCATTERED SHOWERS AND PERHAPS ISOLATED THUNDERSTORMS ARE EXPECTED LATE THURSDAY INTO EARLY FRIDAY. SEAS COULD APPROACH 5 FT AT TIMES ACROSS THE OUTER COASTAL WATERS. SMALL CRAFT ADVISORIES MAY BE NEEDED. SATURDAY...LOW CONFIDENCE. SEAS SHOULD SUBSIDE BELOW 5 FT AND EASTERLY WINDS SHOULD DIMINISH BELOW 20 KTS. SUNDAY...RELATIVELY TRANQUIL WINDS AND SEAS EXPECTED. && .TIDES/COASTAL FLOODING... LAST HIGH TIDE JUST BEFORE MIDNIGHT PRODUCED 0.2 FT SURGE ALONG E MA COAST. SUBSEQUENT HIGH TIDES TODAY INTO THU ARE A BIT LOWER AND SURGE WILL BE MINIMAL...THEREFORE NO IMPACT IS EXPECTED. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ250- 254>256. && $$ SYNOPSIS...DUNTEN/JWD NEAR TERM...JWD SHORT TERM...WTB LONG TERM...BELK AVIATION...JWD MARINE...JWD TIDES/COASTAL FLOODING...JWD
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
317 AM CDT WED SEP 10 2014 .DISCUSSION... 316 AM CDT SHORT TERM FORECAST...TODAY THROUGH THURSDAY NIGHT... CONCERNS IN THE SHORT TERM CONTINUE TO FOCUS ON HEAVY RAINFALL AND SEVERE THUNDERSTORM POTENTIAL THROUGH TODAY. AN ELONGATED AREA OF SURFACE LOW PRESSURE STRETCHED FROM THE OKLAHOMA PANHANDLE INTO CENTRAL IOWA EARLY THIS MORNING...WITH STRONG SURFACE PRESSURE FALLS OF NEARLY 4 MB PER 3 HRS DEVELOPING FROM EASTERN IA INTO SOUTHWEST WI AND NORTHWEST IL. THIS IS WHERE SURFACE LOW WILL CONTINUE TO ORGANIZE AND DEEPEN THIS MORNING IN RESPONSE TO A STRONG SHORT WAVE TROUGH AND STRENGTHENING UPPER JET STREAK LIFTING NORTHEAST FROM THE PLAINS. THE LOW WILL CONTINUE TO LIFT EAST-NORTHEAST ACROSS WI AND LAKE MICHIGAN THROUGH THIS AFTERNOON...TRAILING A SHARP COLD FRONT ACROSS THE FORECAST AREA FROM MIDDAY THROUGH EARLY EVENING. THE AFOREMENTIONED SHORT WAVE OVER THE UPPER MISSISSIPPI VALLEY WILL CONTINUE EAST-NORTHEAST ACROSS WI/NRN IL EARLY THIS MORNING... WITH THE BEST HEIGHT FALLS AND DIFFERENTIAL VORTICITY ADVECTION FROM NOW THROUGH 15Z OR SO. IN ADDITION...STRENGTHENING OF AN UPPER JET STREAK OVER THE NORTHERN LAKES IS EXPECTED TO PRODUCE A COUPLED EXIT/ENTRANCE DIVERGENCE REGION OVER THE AREA DURING THE SAME PERIOD. LOW LEVEL JET WHICH WAS FOCUSED ALONG THE IA/MO BORDER EARLIER IN THE NIGHT HAS INCREASED TO 50-60 KT FROM THE SOUTHWEST PER KEAX VAD WIND PROFILE...AND WILL LIKELY INCREASE MOISTURE TRANSPORT AND THETA-E ADVECTION OVER THE AREA IN THE 09-15Z PERIOD. EXPECTATION IS THUS THAT THE AREA OF ELEVATED CONVECTION/HEAVY STRATIFORM PRECIP OVER IA/WESTERN IL AND NRN MO WILL CONTINUE TO LIFT NORTHEAST ACROSS WRN/NRN IL THROUGH 12Z WITHIN THE STRONGEST AXIS OF MOISTURE TRANSPORT...BEFORE SHIFTING ACROSS THE CENTRAL AND SOUTHEASTERN PARTS OF THE CWA AND ACROSS LAKE MICHIGAN BY MID/LATE MORNING AS SHORT WAVE AND STRONGER FORCING LIFT NORTHEAST AND THE SURFACE LOW DEVELOPS INTO NORTHEAST WI OR NORTHERN LAKE MICHIGAN BY EARLY AFTERNOON. UPSTREAM RAINFALL RATES HAVE GENERALLY BEEN OBSERVED IN THE 0.50-0.75 INCH PER HOUR RANGE IN THE MODERATE TO HEAVY STRATIFORM PRECIP. SYNOPTIC AND MESOSCALE MODELS ARE IN GENERALLY DECENT AGREEMENT WITH QPF AMOUNTS AND PLACEMENT THOUGH TODAY...AND HAVE USED A BLEND OF SUCH GUIDANCE WHICH YIELDS AERIAL AMOUNTS OF 1.50-1.90 INCHES THROUGH LATE WEDNESDAY. THE NORTHWEST HALF OF THE CWA SHOULD SEE HEAVIEST AMOUNTS THIS MORNING...WITH THE SOUTHEAST SEEING MORE OF THEIR RAINFALL THIS AFTERNOON AND VERY EARLY THIS EVENING AHEAD OF THE COLD FRONT. THESE RAINFALL AMOUNTS AND RATES ARE NOT LIKELY TO PRODUCE FLASH FLOODING FOR THE MOST PART...THOUGH AREAS THAT SEE SOME OF THE HEAVIER ELEMENTS TRACK OVERHEAD FOR A WHILE COULD EXPERIENCE SOME PONDING OF WATER OR MINOR FLOODING IN TYPICAL LOW SPOTS. HOWEVER...WITH THE FLASH FLOOD WATCH ALREADY IN PLACE IT WOULD SEEM PREMATURE TO CANCEL THE HEADLINE...ESPECIALLY WITH THE HEAVIER RAIN JUST ARRIVING EARLY THIS MORNING. WITH RESPECT TO THE THREAT OF SEVERE WEATHER...THE LARGE CLUSTER OF RAIN/EMBEDDED THUNDERSTORMS AND CLOUD COVER ACROSS THE AREA THIS MORNING WILL LIKELY IMPACT SURFACE TEMPERATURES AND DEVELOPMENT OF BOUNDARY LAYER ROOTED INSTABILITY THIS AFTERNOON AS THE COLD FRONT MOVES THROUGH. HOWEVER...THE STRONG DYNAMICS OF THIS EARLY AUTUMN STORM AND INCREASING DEEP LAYER BULK SHEAR VALUES WITH THE APPROACHING UPPER JET STREAK THIS AFTERNOON (0-6 KM VALUES 50-60 KTS!) DOES STILL WARRANT SOME RISK OF SEVERE STORMS WITH DAMAGING WINDS ALONG/SOUTHEAST OF THE COLD FRONT THIS AFTERNOON. SPC HAS MOVED THE SLIGHT RISK A LITTLE FARTHER SOUTHEAST OF A PONTIAC TO GARY LINE...AND THIS SEEMS PRUDENT WITH THE POTENTIAL FOR STRONGER INSTABILITY AND OUTFLOW/DIFFERENTIAL HEATING BOUNDARIES TO BE FARTHER SOUTH AFTER THIS MORNINGS LARGE MCS. OUTSIDE OF THE WIND THREAT WITH ANY THUNDERSTORMS TODAY...SOUTH AND SOUTHWEST WINDS WILL INCREASE WITH THE DEEPENING OF THE LOW PRESSURE SYSTEM TO OUR NORTH...WITH GUSTS OF 35-40 MPH EXPECTED. IF ANY SIGNIFICANT DISSIPATION OF CLOUDS AND DESTABILIZATION OCCURS...40-50 KT WINDS JUST ABOVE THE BOUNDARY LAYER COULD BE TAPPED AND RESULT IN HIGHER WIND GUSTS AHEAD OF THE COLD FRONT. EXTENSIVE DEBRIS CLOUD COVER AND PRECIP LEND LOW CONFIDENCE TO THAT OCCURRING HOWEVER. WITH CONSIDERABLE CLOUD COVER EXPECTED MUCH OF THE DAY HAVE TRIMMED HIGH TEMPS BACK TO THE MID-UPPER 70S. OTHERWISE...COLD FRONT CLEARS THE SOUTHEAST CORNER OF THE CWA EARLY THIS EVENING WITH RAIN ENDING FROM THE WEST/NORTHWEST DURING THE AFTERNOON AND EVENING HOURS. MUCH COOLER AIR ARRIVES OVERNIGHT WITH TEMPS DIPPING INTO THE 40S ACROSS FAR NORTHERN/NORTH CENTRAL IL. HIGHS GENERALLY 60-65 EXPECTED THURSDAY...WITH PERHAPS A FEW UPPER 50S ALONG THE FAR NORTH SHORE AREAS. RATZER EXTENDED FORECAST...FRIDAY THROUGH TUESDAY... FRIDAY... UPPER WAVE CURRENTLY OVER BRITISH COLUMBIA IS PROGGED TO DIG ACROSS THE UPPER MIDWEST FRIDAY ALONG WITH MUCH COOLER TEMPERATURES ALOFT WHICH CONTINUES TO SAG SOUTH BEHIND THE STRONG COLD FRONT THAT WILL COME THROUGH LATER TODAY. H85 TEMPS ARE PROGGED TO FALL INTO THE LOW SINGLE DIGITS FRIDAY WHICH WHEN COMBINED WITH DIURNAL HEATING WILL RESULT IN STEEP LOW LEVEL LAPSE RATES. INCREASING ASCENT AHEAD OF THE UPPER WAVE WILL OVERSPREAD THE AREA WITH CHANCES FOR PRECIP INCREASING FROM WEST TO EAST DURING THE AFTERNOON HOURS. WARMER TEMPERATURES IN THE MID LEVEL SHOULD CAP DEEP VERTICAL GROWTH SO MAINLY LIGHT OCCASIONALLY MODERATE SHOWERS WOULD BE EXPECTED. THERE MAY BE SOME LAKE ENHANCEMENT THOUGH AS DEEPER LAKE INDUCED INSTABILITY DEVELOPS OVER LAKE MICHIGAN WHICH STEERING FLOW WILL DRIVE TOWARDS THE ILLINOIS SHORES. AFTERNOON HIGHS ON FRIDAY ARE EXPECTED TO BE IN THE UPPER 50S OVER NORTH CENTRAL ILLINOIS TO LOWER 60S ACROSS EAST CENTRAL ILLINOIS AND NORTHWEST INDIANA...AND AROUND 60 BETWEEN INCLUDING THE CHICAGO METRO. WITH THE DEPARTURE OF THE UPPER WAVE FRIDAY NIGHT AND SURFACE HIGH STARTING TO BUILD INTO THE WESTERN COUNTIES...CLEARING SKIES AND DECREASING WINDS COULD SET THE STAGE FOR STRONG RADIATIONAL COOLING FRIDAY NIGHT...RESULTING IN LOW 40S WEST OF THE FOX RIVER VALLEY BY SATURDAY MORNING. SATURDAY THROUGH TUESDAY... MOST OF THIS PERIOD SHOULD BE DRY UNDER THE INFLUENCE OF SURFACE HIGH PRESSURE...WITH THE EXCEPTION OF MONDAY WHEN ANOTHER UPPER LEVEL DISTURBANCE IS PROGGED TO DIG ACROSS THE REGION FROM CANADA BRINGING ADDITIONAL CHANCES FOR SHOWERS. TEMPERATURES WILL REMAIN WELL BELOW NORMAL THROUGH THE PERIOD WITH HIGHS IN THE 60S...BUT WILL UNDERGO A GRADUAL WARMING TREND PUSHING THE 70 MARK AGAIN BY TUESDAY. DEUBELBEISS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * RAIN OVERSPREADING THE REGION TONIGHT WITH VERY LOW CHANCES FOR EMBEDDED THUNDERSTORM. * THUNDERSTORMS INCREASING IN INTENSITY AND COVERAGE IN THE PREDAWN HOURS WEDNESDAY AS A LOW LEVEL JET DEVELOPS...ALSO RESULTING IN LOW LEVEL WIND SHEAR. * VERY GUSTY S/SSW WINDS DEVELOPING EARLY WEDNESDAY MORNING AND PERSISTING INTO THE AFTERNOON. * ADDITIONAL CHANCE FOR THUNDERSTORMS EARLY TO MID AFTERNOON AHEAD OF A COLD FRONT WHICH WILL SHIFT WINDS TO THE NORTHWEST. BMD //DISCUSSION...UPDATED 06Z... EXPANSIVE AREA OF STRATIFORM RAIN IS OVERSPREADING NORTHERN ILLINOIS CURRENTLY. STEADY RAIN IS EXPECTED THROUGH MUCH OF THE OVERNIGHT HOURS AND WHILE CANNOT RULE OUT AN ISOLATED STROKE OF THUNDER HERE OR THERE...THE INSTABILITY IS RATHER WEAK AND LIGHTNING ACTIVITY IS VERY MINIMAL AWAY FROM THE LOW LEVEL JET CURRENTLY FOCUSED OVER NRN MO. THE LOW LEVEL JET IS PROGGED TO SPREAD OVER NORTHERN ILLINOIS LATE TONIGHT INTO THE PREDAWN HOURS WEDNESDAY MORNING AND SHOULD ALLOW THUNDERSTORM ACTIVITY TO INCREASE AS 60KT LOW LEVEL WINDS TRANSPORT VERY MOIST AIR INTO THE REGION ALONG WITH SOME INSTABILITY. THE MOST FAVORABLE TIMING FOR THESE THUNDERSTORMS REMAINS IN THE MORNING...PRIMARILY BETWEEN 10-15Z FOR THE CHICAGO TERMINALS AND AN HOUR OR TWO EARLIER AT RFD. LLWS CONDITIONS ARE ALSO EXPECTED AS THE LOW LEVEL JET MOVES OVERHEAD. PRECIP SHOULD WANE IN THE LATE MORNING HOURS AS THE FORCING FROM THE LOW LEVEL JET MOVES AWAY. MEANWHILE...LOW PRESSURE CURRENTLY CENTERED OVER THE MID MISSOURI VALLEY WILL LIFT INTO EAST CENTRAL WISCONSIN BY LATE MORNING WITH A TRAILING COLD FRONT PUSHING ACROSS THE TERMINALS MID TO LATE AFTERNOON. ADDITIONAL THUNDERSTORMS ARE POSSIBLE IMMEDIATELY AHEAD AND ALONG THE COLD FRONT AS WE START TO DESTABILIZE AGAIN DIURNALLY. GUIDANCE REMAINS CONSISTENT THAT THE BULK OF THE ACTIVITY WILL FORM SOUTHEAST OF RFD...THOUGH COULD FORM VERY NEAR OR OVER THE CHICAGO TERMINALS. WILL MAINTAIN TEMPO FOR TSRA DURING THE AFTERNOON. WINDS TURN NORTHWESTERLY BEHIND THE FRONT WITH MUCH COOLER AIR PUSHING INTO THE REGION. SOME MODELS SUGGEST THAT THIS COULD RESULT IN A POST FRONTAL MVFR STRATUS TOMORROW EVENING. BMD //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE IN RAIN TONIGHT BUT LOW CONFIDENCE IN TSRA OVERNIGHT. * MEDIUM CONFIDENCE IN TSRA STARTING IN THE PREDAWN HOURS AND GOING THROUGH MID MORNING. * LOW CONFIDENCE IN ADDITIONAL TSRA AHEAD OF THE COLD FRONT. * MEDIUM-HIGH CONFIDENCE IN WIND DIRECTION...LOW-MEDIUM CONFIDENCE IN WIND GUST MAGNITUDE. BMD //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THURSDAY...VFR. FRIDAY...CHC SHRA. SATURDAY...VFR. SUNDAY...VFR. MONDAY...SLT CHC SHRA. BMD && .MARINE... 239 AM CDT WINDS ARE EXPECTED TO RAMP UP QUICKLY LATER THIS MORNING AS SIGNIFICANT EARLY AUTUMN STORM SYSTEM SPREADS OVER THE LAKE LATER THIS MORNING. LOW PRESSURE CURRENTLY OVER IOWA WILL CONTINUE TO THE NORTHEAST AND STRENGTHEN THROUGH THE MORNING. EXPECT SOUTH WINDS TO INCREASE TO 40 KT OVER THE SOUTHERN HALF OF THE LAKE TOWARD DAYBREAK. DO NOT BE CAUGHT OFF GUARD GIVEN THE LIGHTER WINDS CURRENTLY...AS WINDS WILL INCREASE VERY RAPIDLY AS THIS SYSTEM APPROACHES AND WAVES WILL RESPOND ACCORDINGLY. LATER THIS MORNING INTO THE EARLY AFTERNOON WINDS WILL ABATE SOME...THEN AS THE LOW CONTINUES NORTH AND EAST THROUGH LAKE HURON AND INTO QUEBEC...A VERY STRONG PRESSURE GRADIENT ON THE BACK SIDE OF THE LOW COMBINED WITH A SOUTHWARD MOVING COLD FRONT WILL BRING A PERIOD OF GALE FORCE WINDS ALONG THE NORTHERN HALF OF THE LAKE. CONFIDENCE STILL REMAINS LOW WITH REGARDS TO GALES DEVELOPING ON THE SOUTHERN HALF OF THE LAKE IN THE NORTHWEST WINDS BEHIND THE LOW...BUT IF THE LOW TRACKS A BIT FARTHER SOUTH...GALES STILL REMAIN POSSIBLE. WHILE WE FEEL THAT WINDS TO 30 KT ARE MORE LIKELY ON THE SOUTH HALF...FEEL IT IS PRUDENT TO HANG ONTO THE WATCH LATER THIS EVENING AND WILL OUTLINE THE DETAILS IN THE MARINE WEATHER WARNING PRODUCT. REGARDLESS...WAVES WILL BUILD QUICKLY AS WELL THIS MORNING IN RESPONSE TO THE STRONG WINDS...THEN BUILD AND REMAIN HIGH THROUGH THE LATTER HALF OF THE WEEK AS NORTH FLOW REMAINS IN PLACE. KMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022- ILZ032 UNTIL 1 PM WEDNESDAY. BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL NOON WEDNESDAY. FLASH FLOOD WATCH...ILZ023-ILZ033-ILZ039...7 AM WEDNESDAY TO 7 PM WEDNESDAY. IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...7 AM WEDNESDAY TO 7 PM WEDNESDAY. LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740- LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 AM WEDNESDAY TO 7 PM WEDNESDAY. GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 PM WEDNESDAY TO 10 AM THURSDAY. GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...5 PM WEDNESDAY TO 10 AM THURSDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
  [top] Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 256 AM CDT Wed Sep 10 2014 .SHORT TERM...(Today) ISSUED AT 256 AM CDT WED SEP 10 2014 Heavy rainfall event is commencing across west-central Illinois early this morning, with 07z/2am radar imagery showing rain across the western half of the KILX CWA. Further west, very heavy rain and flash flooding is occurring across northern Missouri, where several convective systems have trained over the same locations. Latest IR satellite imagery shows first system dissipating west of Quincy, while another flare up of convection is developing further west along the Iowa/Missouri border. This activity is being fed by a 60-65kt 850mb jet streak as seen on the KEAX VWP and is tracking E/SE along a stationary frontal boundary extending from southern Iowa into eastern Missouri. As low pressure currently over southwest Iowa deepens and lifts into Wisconsin later this morning, this heavier precip area will gradually shift into west-central Illinois. With precipitable water values exceeding 2 inches, high rainfall rates of greater than 1 inch per hour will be possible. Several locations along/west of I-55 already picked up between 1 and 3 inches of rain yesterday, so any additional rainfall could potentially lead to flash flooding. As a result, current Flash Flood Watch for much of central Illinois along and north of a Shelbyville to Paris line will remain in effect today. Severe weather threat remains uncertain, as widespread showers and thunderstorms this morning will stabilize a good portion of the area. Best bet for adequate destabilization this afternoon will be along southern/eastern periphery of rain area. Based on current radar trends and 00z model output, think this will mainly be focused across the S/SE CWA. Latest convective outlook from SPC is trending in that direction as well, with the slight risk area being shifted further southeast than previously forecast. South of the precip area where afternoon high temperatures will reach the lower to middle 80s, CAPE values will likely reach the 1500 to 2000J/kg range across southern Illinois into central/southern Indiana. Outflow boundary from morning convection interacting with this unstable airmass and strong low-level wind shear will likely produce a line of strong to severe thunderstorms somewhere along/south of a Shelbyville to Paris line by mid to late afternoon. Main severe threat will be damaging wind gusts as the storms sink southeastward into the evening hours. && .LONG TERM...(Tonight through Tuesday) ISSUED AT 256 AM CDT WED SEP 10 2014 Low pressure will continue to track northeastward into the Great Lakes tonight, dragging a strong cold front through central Illinois. Boundary is progged to be along a Chicago to Saint Louis line early this evening, then along the Ohio River by Thursday morning. Based on this timing, will carry categorical PoPs across the E/SE CWA this evening, tapering down to just chance after midnight. Further northwest, will mention chance of showers this evening, followed by dry weather after midnight. Once front passes, much cooler conditions will be noted on Thursday. Despite a good deal of sunshine, strong CAA pushing 850mb temps to between 10 and 14c will result in highs only reaching the middle to upper 60s. Even cooler weather will be on tap for Friday, as 850mb temps drop further and clouds increase in advance of a lingering 500mb trough axis. Models continue to show this feature passing Friday night, accompanied by scattered showers. Latest ECMWF is quite bullish with its QPF Friday night, while the GFS is much drier. Think the precip will be mainly diurnal in nature, so am not ready to raise PoPs significantly for Friday night. Will bring low chance PoPs across the western half of the CWA Friday afternoon, then will only go with slight chance PoPs Friday night as daytime instability fades. Once this feature passes, strong Canadian high pressure will dominate the weather this weekend. Resulting high temperatures on Saturday and Sunday will only be in the 60s, while overnight lows dip into the 40s. Next northern stream short-wave will swing through the region early next week, although timing discrepancies exist among the models. GFS is slightly faster with the feature, bringing it across central Illinois on Monday, while the ECMWF delays in until Monday night. Due to timing differences and very limited moisture supply, have opted to keep the forecast dry through Tuesday at this time. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 1153 PM CDT TUE SEP 9 2014 Showers and a few thunderstorms with light to moderate rain will progress eastward across central IL the remainder of the night. Steady rains will eventually reach the Indiana border before sunrise, including CMI and DEC. PIA will have the better chances of flooding type rains by morning, as a 45kt low level jet focuses into WC IL after midnight and moisture pooling increases just north of the warm front. SPI will be close to the line of storms and heavy rains approaching from N MO, but it appears there should be a slight northward drift to keep them just north of SPI. Will need to watch that closely for due eastward progression, for lower vis and cigs in heavy rains. At this point, we only tempo`d heavy rains in PIA between 08z-12z. Most areas should remain VFR, with short periods of MVFR vis or ceilings in mod/hvy rain. The NAM keeps indicating LIFR ceilings across the board, but GFS and EC, and to some extent the RAP soundings do not support that scenario. Low level wind shear still looks like a good bet for later tonight for our western TAFs as the southerly LLJ increases to 45kt around 2k FT. We did not include DEC and CMI in the LLWS for now, based on the latest RAP model output. As the cold front approaches tomorrow, winds will increase out of the south-southwest, with gusts to near 30kt at times. There appears to be decreasing support for strong to severe storms tomorrow unless we see a significant period of sunshine later morning and early afternoon ahead of the front. We left just a VCTS in the afternoon for now. && .ILX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH through this evening FOR ILZ027>031-036>038- 040>042-047>051. FLASH FLOOD WATCH from 1 PM CDT this afternoon through late tonight FOR ILZ043>046-052>057-061. && $$ SHORT TERM...BARNES LONG TERM...BARNES AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1219 AM CDT WED SEP 10 2014 .DISCUSSION... 1100 PM CDT FAIRLY STRATIFORM PRECIP WITH SOME EMBEDDED CONVECTION CONTINUES TO GRADUALLY MAKE EASTWARD PROGRESS INTO CENTRAL AND NORTH-CENTRAL ILLINOIS IN RESPONSE TO AN UPPER WAVE MOVING EAST-NORTHEAST INTO WESTERN ILLINOIS AND HAS NOT REALLY INTENSIFIED IN THE LAST FEW HOURS. THE BETTER CONVECTION CONTINUES ALONG A STATIONARY SURFACE BOUNDARY ACROSS NORTHERN MISSOURI WHERE AN INCREASING LOW LEVEL JET IS DEVELOPING. THE SURFACE LOW CONTINUES TO BE ELONGATED FROM SOUTHWEST IOWA INTO THE TEXAS PANHANDLE. RAIN AND SOME EMBEDDED THUNDER WILL CONTINUE TO WORK INTO THE WESTERN CWA OVER THE NEXT FEW HOURS WITH THUNDER BECOMING MORE PREVALENT AS THE RAIN SPREADS EASTWARD OVERNIGHT. RAIN HAS GENERALLY BEEN LIGHT TO MODERATE IN INTENSITY TO THE WEST AND THIS WILL LIKELY BE THE CASE AS IT MOVES INTO THE CWA OVER THE NEXT SEVERAL HOURS. HAVE SLOWED THE EASTWARD PROGRESS IN THE GRIDS OVERNIGHT. THE SURFACE LOW WILL CONSOLIDATE WITH PRESSURE FALLS SUGGESTING THIS WILL OCCUR INTO SOUTHWEST AND CENTRAL IOWA. CONVECTION WILL LIKELY CONTINUE TO EXPAND TO THE EAST AND SOUTHEAST OF THE SURFACE LOW BUT ONGOING CONVECTION OVER NORTHERN MISSOURI MAY LIMIT THE FEED OF MOISTURE AND THEREFORE THE INTENSITY OF THE RAINFALL WHICH WILL THEN TRACK INTO THE CWA IN THE MORNING. WITH THE LOW PASSING NEAR OR NORTHWEST OF THE CWA DURING THE MORNING THE THREAT FOR MORE INTENSE CONVECTION/RAINFALL WILL BE DURING THE MORNING ACROSS MUCH OF THE AREA. THE NOW STATIONARY BOUNDARY IS EXPECTED TO MARCH NORTHWARD BUT IT IS NOT CERTAIN HOW QUICKLY THIS WILL OCCUR AND WILL LIKELY HAVE A ROLE IN CONVECTIVE EVOLUTION THROUGH MIDDAY OR SO. GIVEN THAT THERE IS STILL PLENTY OF EVOLUTION THAT NEEDS TO OCCUR WITH THE SURFACE LOW AND THE SHIFTING OF THE LOW LEVEL JET INTO THE WESTERN CWA WILL CONTINUE WITH THE FLASH FLOOD WATCH THOUGH THE THREAT THROUGH MUCH OF THE OVERNIGHT APPEARS TO BE WANING. A RESURGENCE IN INTENSITY REMAINS POSSIBLE FOR EAST AND SOUTHEAST AREAS WEDNESDAY AFTERNOON AS THE COLD FRONT PASSES SO WILL MAINTAIN THE HEADLINE THERE AS WELL. MDB //PREV DISCUSSION... 335 PM CDT SHORT TERM...TONIGHT THROUGH FRIDAY... MAIN CONCERNS FOR THE FORECAST PERIOD REMAIN THUNDERSTORMS AND HEAVY RAINFALL ASSOCIATED WITH AN UNUSUALLY STRONG LATE SUMMER COLD FRONT AND UPPER TROUGH IMPACTING THE REGION FROM LATE TONIGHT INTO WEDNESDAY EVENING. THEN... FOLLOWING THE PASSAGE OF THIS SYSTEM... THE FOCUS WILL SHIFT TO THE TEMPERATURE FORECAST AND THE FIRST REAL TASTE OF AUTUMNAL WEATHER FOR LATER THIS WEEK. FOR THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING...CONDITIONS WILL BE THE RELATIVE CALM BEFORE THE STORM. THE SFC LOW IS BEGINNING TO DEEPEN OVER THE CNTRL PLAINS WHILE HIGH PRESSURE MOVES OFF THE EAST COAST. INCREASING SOUTHERLY FLOW IS RAMPING UP OVER THE LOWER AND MIDDLE MISSISSIPPI VALLEY...SETTING UP VERY STRONG WARM/MOIST ADVECTION POINTING INTO THE MIDWEST. THIS AFTERNOON...CONVECTIVE ACTIVITY HAS ALREADY BROKEN OUT ALONG THE NOSE OF A 50 KT LOW LEVEL JET...EXTENDING FROM WRN IOWA INTO CNTRL IL. THIS STRONG LOW LEVEL JET WILL CONTINUE TO PUMP MOISTURE INTO THE REGION WHILE MOISTURE ASSOCIATED WITH THE REMNANTS OF HURRICANE NORBERT ADVECT OVER THE REGION AT THE MID LEVELS. THE MODELS HAVE BEEN VERY CONSISTENT ON ADVERTISING A SWATH OF PWATS OF 2.0 TO 2.5 INCHES POOLING AHEAD OF THE FRONT. THE LOW LEVEL WARM ADVECTION AHEAD OF THE FRONT...CONVERGENCE ALONG THE FRONT...A STRONG MID LEVEL SHORTWAVE AND A COUPLED JET ALOFT WILL ALL COMBINE TO GENERATE STRONG AND PERSISTENT THUNDERSTORMS. THERE SHOULD BE ADEQUATE SHEAR IN THE LOW LEVELS BETWEEN SLY SFC WINDS AND 50 KT SWLY WINDS AT 925-850MB TO SUPPORT AN INITIAL CONVECTIVE MODE SUPPORTING SOME ISOLATED SUPERCELLS ALONG WITH THE GENERAL THUNDER. SPC HAS OUTLOOKED THE ENTIRE CWA WITH A SLIGHT RISK OVER SEVERE THUNDERSTORMS...WITH THE PRIMARY THREATS BEING STRONG DAMAGING WINDS AND MARGINALLY SEVERE HAIL. THE 12Z SOUNDINGS FROM ILX/DVN INDICATE THE FREEZING LEVEL AT 13KFT AND WITH PERSISTENT WARM ADVECTION AHEAD OF THE COLD FRONT...THE FREEZING LEVEL WILL LIKELY RISE SOME UNTIL THE FROPA. SO...WHILE THE ENVIRONMENT SHOULD SUPPORT SOME STRONG ROTATING UPDRAFTS SUFFICIENT FOR LARGE HAIL...THE HIGH FREEZING LEVELS SHOULD GIVE AMPLE TIME FOR SOME MELTING. AS FOR THE WIND THREAT...WITH THE STRONG LOW LEVEL JET POINTING OVER THE AREA...STRONG WINDS SHOULD BE ABLE TO MIX DOWN...PARTICULARLY IN THE WARM SECTOR AHEAD OF THE FRONT WHERE SURFACE BASED CONVECTION SHOULD BE ABLE TO FORM. SO...STRONG...DAMAGING WINDS WILL BE A CONCERN DURING THE INITIAL THUNDERSTORM DEVELOPMENT LATE THIS EVENING. HEAVY RAINFALL... THROUGH THE NIGHT...CONVECTIVE MODE WILL TRANSITION OVER TO MORE LINES OR CLUSTERS...AND EVENTUALLY CONGEALING INTO A LARGE AREA OF THUNDERSTORMS. WITH FLOW ABOVE THE BOUNDARY LEVEL TO ABOUT 700MB SWLY...AND WLY-WNWLY JET-LEVEL WINDS...CELL MOVEMENT WITHIN THE OVERALL THUNDERSTORM AREA WILL BE TO THE NORTHEAST WHILE THE LARGER SCALE PATTERN IS SLOWLY PROGRESSIVE TO THE EAST. SO...ANTICIPATE THAT THERE SHOULD BE AMPLE OPPORTUNITY FOR REPEATED DEVELOPMENT OR TRAINING OF STORMS. ALL ELEMENTS ARE COMING TOGETHER FOR A SIGNIFICANT HEAVY RAIN EVENT. STORMS WILL BE EFFICIENT RAIN PRODUCERS GIVEN THE DEEP LAYER MOISTURE AND RAINFALL RATES OF 2 TO 3 INCHES PER HOUR FROM SOME STORMS WILL NOT BE OUT OF THE QUESTION. FORTUNATELY...THE PATTERN WILL BE SLOWLY...BUT STEADILY PROGRESSIVE...SO RAINFALL WILL BE WIDESPREAD RATHER THAN CONFINED TO A SMALL AREA. LATEST THINKING IS THAT STORM TOTAL QPF SHOULD BE ARND 2.0 TO 2.5 INCHES. IN AREAS OF TRAINING OR REPEATED STORM DEVELOPMENT...LOCALIZED AREAS OF 3 TO 5 INCHES TOTAL RAINFALL WILL BE POSSIBLE. THE MOST FAVORED TIMING FOR THE STRONGEST STORMS WILL BE LATE THIS EVENING AND OVERNIGHT. THERE MAY BE A BRIEF LULL IN ACTIVITY DURG THE MORNING HOURS...HOWEVER...EXPECT ANOTHER UPTICK IN ACTIVITY DURG THE LATE MORNING/EARLY AFTERNOON AS THE COLD FRONT PUSHES THROUGH NWRN INDIANA. MAJOR CHANGE IN AIRMASS... FOLLOWING THE FRONTAL PASSAGE WEDNESDAY AFTERNOON AND EVENING...LOW WILL TURN NWLY TO NLY BEHIND THE FRONT. WEAK CYCLONIC CURVATURE AND COLD ADVECTION WILL BRING SOME INSTABILITY SHOWERS IN THE COLDER AIR BEHIND THE FRONT...THROUGH THURSDAY...A BROAD UPPER TROUGH WILL CARVE OUT OVER THE CNTRL CONUS. A SERIES OF NORTHERN STREAM SHORTWAVES WILL HELP INCREASE THE AMPLITUDE OF THE UPPER TROUGH WHILE SUPPLYING MUCH COOLER AIR TO THE REGION. BY THURSDAY MORNING...TEMPERATURES SHOULD DROP OFF INTO THE MIDDLE 40S OVER THE NWRN PORTION OF THE CWA...INCLUDING THE ROCKFORD METRO AREA. SOUTHEAST OF A LINE FROM CHICAGO TO PONTIAC...LOWS THURSDAY MORNING SHOULD REMAIN IN THE LOWER TO MIDDLE 50S. TEMPERATURES WILL NOT HAVE MUCH OPPORTUNITY FOR DIURNAL WARMING THROUGH THE DAY GIVEN THE PERSISTENT COLD ADVECTION...WITH HIGHS THURSDAY ONLY IN THE LOWER TO MIDDLE 60S. THERE IS EVEN A CHANCE THAT THE ROCKFORD AREA MAY NOT BE ABLE TO GET OUT OF THE UPPER 50S. BY FRIDAY MORNING... TEMPERATURES IN THE LOWER TO MIDDLE 40S WILL COVE THE WHOLE CWA...AWAY FROM THE URBANIZED PORTION OF THE CHICAGO METRO AREA. FOR FRIDAY...MAX TEMPS SHOULD BE EVEN LOWER THAN THURSDAY...WITH NCNTRL/NWRN IL REMAINING IN THE MIDDLE 50S WHILE NERN IL/NWRN IN SHOULD SEE TEMPS LOW OUT IN THE LOW 60S. KREIN LONG TERM...FRIDAY NIGHT THROUGH TUESDAY... THE BIG STORY IN THE EXTENDED PERIOD IS THE REINFORCING SHOT OF UNSEASONABLY COOL AIR THAT WILL BRING EARLY TO MID OCTOBER TEMPERATURES OVER THE WEEKEND. IN RESPONSE TO PERSISTENT HIGH AMPLITUDE RIDGING ALONG THE WEST COAST UP TO ALASKA...A DEEP MEAN TROUGH WILL LOCK IN OVER THE EASTERN HALF OF CANADA INTO THE NORTHERN TIER OF THE EASTERN HALF OF THE CONUS. THIS MID/UPPER PATTERN IS SIMILAR TO WHAT OCCURRED MUCH OF WINTER 2013-14 AND WILL RESULT IN BELOW NORMAL TEMPERATURES CONTINUING INTO EARLY NEXT WORK WEEK. GUIDANCE IS CONSISTENT IN BRINGING A QUICK MOVING BUT DEEP SHORT WAVE TROUGH OR CLOSED LOW ACROSS THE REGION FRIDAY NIGHT...WITH A DECENT CHANCE FOR A PERIOD OF RAIN SHOWERS. MAINTAINED CHANCE POPS IN SMART BLEND...BUT THESE MAY NEED TO BE INCREASED IF TRENDS HOLD. AIR MASS WILL BE ANOMALOUSLY COOL...DIPPING CLOSE TO 0C AT 850 MB OVER FAR NORTHERN ILLINOIS BY 12Z SATURDAY. PROGRESSION OF SYSTEM WILL BE KEY IN HOW COLD LOWS ARE BY EARLY SATURDAY...AS LESS PROGRESSIVE/TIGHTER GRADIENT INDICATED BY RECENT ECMWF RUNS WOULD INTRODUCE CLOUD COVER CONCERNS. STILL...COLD ADVECTION ALONE LIKELY SUPPORTS LOWS IN 40S EVERYWHERE BUT IMMEDIATE CITY OF CHICAGO. POTENTIAL DOES EXIST FOR LAKE EFFECT RAIN SHOWERS INTO SATURDAY MORNING FOR PORTIONS OF SHORE...MAINLY NW IN...BEFORE SUBSIDENCE ARRIVES FROM EXPANSIVE HIGH PRESSURE SPREADING IN FROM WEST. HIGH TEMPERATURES LOOK TO STRUGGLE INTO LOWER 60S SATURDAY AFTERNOON. ANOMALOUSLY COOL AIR MASS AND GOOD RADIATIONAL COOLING SETUP WITH HIGH PRESSURE OVERHEAD SATURDAY NIGHT FAVORS AREAS OUTSIDE CHICAGO DOWN INTO AT LEAST LOWER 40S...WITH UPPER 30S POSSIBLE IN TYPICAL COLD SPOTS. DID UNDERCUT SMART BLEND INITIALIZATION FOR LOWS EARLY SUNDAY...AND LOWS IN 30S IN OUTLYING AREAS COULD BE MORE WIDESPREAD THAN IN CURRENT FORECAST IF THERE ARE NO CLOUD COVER ISSUES. WITH MEAN TROUGH OVER REGION...TEMPERATURES WILL REMAIN BELOW NORMAL REMAINDER OF EXTENDED...THOUGH SLOW MODERATION THROUGH 60S IS EXPECTED SUNDAY AND MONDAY. PREVIOUS TWO RUNS OF ECMWF INDICATE ANOTHER SHORT WAVE/REINFORCING COLD FRONT MONDAY/MONDAY NIGHT. CONFIDENCE IS LOWER IN THIS PERIOD DUE TO FEATURE BEING MUCH LESS ROBUST ON GFS AND ITS ENSEMBLES. FOR NOW...GRIDS INDICATE A SLIGHT CHANCE FOR SHOWERS ON MONDAY. RC && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * RAIN OVERSPREADING THE REGION TONIGHT WITH VERY LOW CHANCES FOR EMBEDDED THUNDERSTORM. * THUNDERSTORMS INCREASING IN INTENSITY AND COVERAGE IN THE PREDAWN HOURS WEDNESDAY AS A LOW LEVEL JET DEVELOPS...ALSO RESULTING IN LOW LEVEL WIND SHEAR. * VERY GUSTY S/SSW WINDS DEVELOPING EARLY WEDNESDAY MORNING AND PERSISTING INTO THE AFTERNOON. * ADDITIONAL CHANCE FOR THUNDERSTORMS EARLY TO MID AFTERNOON AHEAD OF A COLD FRONT WHICH WILL SHIFT WINDS TO THE NORTHWEST. BMD //DISCUSSION...UPDATED 06Z... EXPANSIVE AREA OF STRATIFORM RAIN IS OVERSPREADING NORTHERN ILLINOIS CURRENTLY. STEADY RAIN IS EXPECTED THROUGH MUCH OF THE OVERNIGHT HOURS AND WHILE CANNOT RULE OUT AN ISOLATED STROKE OF THUNDER HERE OR THERE...THE INSTABILITY IS RATHER WEAK AND LIGHTNING ACTIVITY IS VERY MINIMAL AWAY FROM THE LOW LEVEL JET CURRENTLY FOCUSED OVER NRN MO. THE LOW LEVEL JET IS PROGGED TO SPREAD OVER NORTHERN ILLINOIS LATE TONIGHT INTO THE PREDAWN HOURS WEDNESDAY MORNING AND SHOULD ALLOW THUNDERSTORM ACTIVITY TO INCREASE AS 60KT LOW LEVEL WINDS TRANSPORT VERY MOIST AIR INTO THE REGION ALONG WITH SOME INSTABILITY. THE MOST FAVORABLE TIMING FOR THESE THUNDERSTORMS REMAINS IN THE MORNING...PRIMARILY BETWEEN 10-15Z FOR THE CHICAGO TERMINALS AND AN HOUR OR TWO EARLIER AT RFD. LLWS CONDITIONS ARE ALSO EXPECTED AS THE LOW LEVEL JET MOVES OVERHEAD. PRECIP SHOULD WANE IN THE LATE MORNING HOURS AS THE FORCING FROM THE LOW LEVEL JET MOVES AWAY. MEANWHILE...LOW PRESSURE CURRENTLY CENTERED OVER THE MID MISSOURI VALLEY WILL LIFT INTO EAST CENTRAL WISCONSIN BY LATE MORNING WITH A TRAILING COLD FRONT PUSHING ACROSS THE TERMINALS MID TO LATE AFTERNOON. ADDITIONAL THUNDERSTORMS ARE POSSIBLE IMMEDIATELY AHEAD AND ALONG THE COLD FRONT AS WE START TO DESTABILIZE AGAIN DIURNALLY. GUIDANCE REMAINS CONSISTENT THAT THE BULK OF THE ACTIVITY WILL FORM SOUTHEAST OF RFD...THOUGH COULD FORM VERY NEAR OR OVER THE CHICAGO TERMINALS. WILL MAINTAIN TEMPO FOR TSRA DURING THE AFTERNOON. WINDS TURN NORTHWESTERLY BEHIND THE FRONT WITH MUCH COOLER AIR PUSHING INTO THE REGION. SOME MODELS SUGGEST THAT THIS COULD RESULT IN A POST FRONTAL MVFR STRATUS TOMORROW EVENING. BMD //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE IN RAIN TONIGHT BUT LOW CONFIDENCE IN TSRA OVERNIGHT. * MEDIUM CONFIDENCE IN TSRA STARTING IN THE PREDAWN HOURS AND GOING THROUGH MID MORNING. * LOW CONFIDENCE IN ADDITIONAL TSRA AHEAD OF THE COLD FRONT. * MEDIUM-HIGH CONFIDENCE IN WIND DIRECTION...LOW-MEDIUM CONFIDENCE IN WIND GUST MAGNITUDE. BMD //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THURSDAY...VFR. FRIDAY...CHC SHRA. SATURDAY...VFR. SUNDAY...VFR. MONDAY...SLT CHC SHRA. BMD && .MARINE... 221 PM CDT THE MAIN FORECAST CONCERNS CONTINUE TO CENTER AROUND A SIGNIFICANT STORM SYSTEM EXPECTED TO IMPACT THE GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT. SOUTHERLY WINDS ARE EXPECTED TO INCREASE RAPIDLY LATE TONIGHT AS A STRENGTHENING AREA OF LOW PRESSURE MOVES FROM IOWA INTO SOUTHWESTERN WISCONSIN. SOUTHERLY GALES OF 35 TO 40 KT ARE EXPECTED BY EARLY MORNING ACROSS APPROXIMATELY THE SOUTHERN HALF OF THE LAKE...AND THESE STRONG WINDS WILL CONTINUE THROUGH THE AFTERNOON. THE LOW IS THEN EXPECTED TO SHIFT ACROSS THE NORTHERN PORTION OF THE LAKE BY WEDNESDAY EVENING...AND THIS SHOULD RESULT IN A SHORT PERIOD OF LIGHT AND VARIABLE WINDS NEAR ITS TRACK EARLY THURSDAY EVENING. HOWEVER...ONCE THIS LOW SHIFTS EAST OF THE LAKE BY LATER WEDNESDAY EVENING...A STRONG COLD FRONT WILL PUSH OVER THE LAKE. THIS SHOULD ALLOW FOR A PERIOD OF STRONG NORTH-NORTHWESTERLY WINDS OVER THE LAKE INTO THURSDAY. AT THIS TIME...IT APPEARS THE MAIN THREAT FOR GALES MAY SHIFT OVER THE NORTHERN HALF OF THE LAKE INTO EARLY THURSDAY MORNING...WITH NEAR GALE FORCE WINDS POSSIBLE OVER THE SOUTHERN END OF THE LAKE. WINDS WILL GRADUALLY ABATE SOME INTO THE LATER PORTION OF THE WEEK AS HIGH PRESSURE BUILDS IN ACROSS THE PLAINS AND UPPER MIDWEST. HOWEVER...THE NORTHERLY FETCH WILL LIKELY CONTINUE TO PRODUCE SOME HIGHER 4 + FOOT WAVES THROUGH AT LEAST FRIDAY. ANOTHER SYSTEM COULD IMPACT PORTIONS OF THE LAKE ON SATURDAY...POSSIBLY LEADING TO A PERIOD OF ENHANCED NORTHERLY WINDS AGAIN. HOWEVER...UNCERTAINTY IS HIGH WITH THIS SYSTEM. IF THE SYSTEM DOES PAN OUT...IT COULD RESULT IN WAVES HIGH ENOUGH TO SUPPORT A SMALL CRAFT ADVISORY INTO SATURDAY. AS FOR HEADLINES...WE HAVE ISSUED A GALE WARNING FOR THE SOUTHERN HALF OF THE LAKE...INCLUDING THE NEAR SHORES...FOR THE DAY ON WED WHEN STRONG SOUTHERLY WINDS ARE EXPECTED. DUE TO UNCERTAINTIES ON HOW STRONG THE NORTHERLY WINDS WILL BE ON OVER SOUTHERN LAKE MICHIGAN ON THE BACK SIDE OF THE SYSTEM...WE HAVE OPTED TO KEEP THE WATCH IN PLACE FOR WEDNESDAY NIGHT FOLLOWING THE SOUTHERLY GALE EVENT. HOWEVER...OVER THE NORTHERN PORTION OF THE LAKE NORTHERLY GALES APPEAR MORE LIKELY WEDNESDAY NIGHT..SO WE HAVE ISSUED THE GALE WARNING THERE FOR WEDNESDAY EVENING THROUGH EARLY THURSDAY. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022- ILZ032 UNTIL 1 PM WEDNESDAY. BEACH HAZARDS STATEMENT...ILZ006-ILZ014...5 AM WEDNESDAY TO NOON WEDNESDAY. FLASH FLOOD WATCH...ILZ023-ILZ033-ILZ039...7 AM WEDNESDAY TO 7 PM WEDNESDAY. IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...7 AM WEDNESDAY TO 7 PM WEDNESDAY. LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740- LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 AM WEDNESDAY TO 7 PM WEDNESDAY. GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 PM WEDNESDAY TO 10 AM THURSDAY. GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...5 PM WEDNESDAY TO 10 AM THURSDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 1153 PM CDT Tue Sep 9 2014 .UPDATE... ISSUED AT 900 PM CDT TUE SEP 9 2014 The 35-45kt low level jet around 850mb is progressing toward IL from the SW. Moisture transport is increasing as a result, with PWAT values climbing toward 2 inches. The nearly stationary warm from angled from NW to SE in eastern Missouri will continue to provide a lifting mechanism for shower/storm development the rest of the night. A progressive MCS is forecast by the high res models to move from NW Missouri across N IL overnight, which will possibly clip our NW counties after midnight. Areas NW of the IL river will have the best chances of getting heavy rain and strong winds from that complex. We kept categorical PoPs for that area overnight, with heavy rain in the grids. The flash flood watch coverage still looks good for timing and coverage. No changes will be needed there. The severe threat for Wed afternoon still hinges greatly on the amount of sunshine that develops ahead of the cold front. Wind shear will be present, as well as plenty of moisture, so instability will be the question-mark. Forecast soundings show limited instability even during the afternoon due to a moist adiabatic profile, but areas of clearing and heating can quickly produce high CAPEs. Will keep tomorrows forecast as is, with severe potential for nearly all of our counties except western portions of Knox and Stark counties. Even update mainly for weather/PoPs. && .SHORT TERM...(Tonight) ISSUED AT 305 PM CDT TUE SEP 9 2014 Issued a flash flood watch for areas from I-55 west from this afternoon through 7 pm Wed. Issued flash flood watch for east central IL for Wed afternoon and Wed evening. MCS still affecting a part of central IL with showers and thunderstorms sw of I-74 and west of I-57. Thunderstorms with heavy rains over parts of Morgan and southern Sangamon counties. Have increased chances of showers and thunderstorms over central and western areas tonight with heaviest rains shifting into areas nw of the IL river during the night. SPC continues a slight risk of severe storms from I-55 nw into tonight with main threat damaging wind gusts where 30% risk nw of IL river. Muggy lows in the upper 60s to around 70F with south southeast winds prevailing tonight. && .LONG TERM...(Wednesday through Tuesday) ISSUED AT 305 PM CDT TUE SEP 9 2014 Showers and thunderstorms will likely be ongoing to start the day for much of the forecast area west of I-55. This convective complex will be tied fairly closely to a deepening surface low that will be lifting into the Great Lakes region during the day. East of I-55 the day will likely start out dry. Then, attention turns to the cold front trailing from the surface low. This strong front will sweep through the forecast area, mainly during the Wednesday afternoon and evening hours. Unfortunately, there are still model disagreements with the speed of the front, differences that will likely have a significant impact on our severe weather threat. The ECMWF remains the slowest, while the NAM has trended faster and is now closer to the GFS speed. However, WPC does not favor the NAM`s recent trend of a deeper surface low and associated faster frontal speed. So, will continue to favor the more consistent ECMWF (although the GFS has been fairly consistent with is quicker solution). Severe storms and heavy rainfall are still a threat until the cold front clears the area. The main severe storm threat still appears to be in the Wednesday afternoon/evening hours along/ahead of the cold front where the best pre-frontal instability (1500-2500 j/kg) and bulk shear (35-45 kts) will be co-located. However, if a faster frontal speed verifies, the instability will likely end up quite a bit lower and reduce the severe threat. Any storms until the front clears the area have the potential to be heavy rain producers, with precipitable water values apt to be in excess 2 inches. Once the strong cold front clears the area by late Wednesday night, a much cooler than normal weather pattern should linger through the end of the forecast period. Upper level troffing should remain in place, accompanied by a Canadian surface high more often than not. There are still some stronger waves expected to track through the mean trof that may produce rainfall. However, model agreement in this regard still leaves much to be desired, especially next week. At this point, the best model clustering suggests showers are possible later Friday into Friday night, and this is the only period I have left slight chances for showers in place. Temperatures to start the period should average 60s for highs and 40s for lows, climbing into the 70s and 50s respectively by the end of the period. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 1153 PM CDT TUE SEP 9 2014 Showers and a few thunderstorms with light to moderate rain will progress eastward across central IL the remainder of the night. Steady rains will eventually reach the Indiana border before sunrise, including CMI and DEC. PIA will have the better chances of flooding type rains by morning, as a 45kt low level jet focuses into WC IL after midnight and moisture pooling increases just north of the warm front. SPI will be close to the line of storms and heavy rains approaching from N MO, but it appears there should be a slight northward drift to keep them just north of SPI. Will need to watch that closely for due eastward progression, for lower vis and cigs in heavy rains. At this point, we only tempo`d heavy rains in PIA between 08z-12z. Most areas should remain VFR, with short periods of MVFR vis or ceilings in mod/hvy rain. The NAM keeps indicating LIFR ceilings across the board, but GFS and EC, and to some extent the RAP soundings do not support that scenario. Low level wind shear still looks like a good bet for later tonight for our western TAFs as the southerly LLJ increases to 45kt around 2k FT. We did not include DEC and CMI in the LLWS for now, based on the latest RAP model output. As the cold front approaches tomorrow, winds will increase out of the south-southwest, with gusts to near 30kt at times. There appears to be decreasing support for strong to severe storms tomorrow unless we see a significant period of sunshine later morning and early afternoon ahead of the front. We left just a VCTS in the afternoon for now. && .ILX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH through Wednesday evening FOR ILZ027>031- 036>038-040>042-047>051. FLASH FLOOD WATCH from Wednesday afternoon through late Wednesday night FOR ILZ043>046-052>057-061. && $$ UPDATE...SHIMON SHORT TERM...07 LONG TERM...BAK AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1149 PM CDT TUE SEP 9 2014 .UPDATE... ISSUED AT 905 PM CDT TUE SEP 9 2014 REALLY THE ONLY CONCERN TONIGHT IS HEAVY RAIN AND FLOODING AS SEVERE THREAT VERY LOW WITH SATURATED SOUNDING AND LIMITED SUB CLOUD BUOYANCY. LINEAR MCS CONTINUES SAGGING S/SE INTO LOW LEVEL MOIST AXIS AND IS INTERCEPTING MAIN LOW LEVEL JET AND MOISTURE TRANSPORT FEED. MUCH OF CONVECTION AND HEAVY RAIN CONCERNS WILL EXIST NEAR TO SOUTH OF I-80 REST OF EVE... WITH STRATIFYING PCPN SHIELD ACROSS NORTH. CONCERNS EXIST THAT THE LONGER THIS CONVECTION CONTINUES TO OUR SOUTH TONIGHT INTERRUPTING FOCUS OF LOW LEVEL JET AND MOISTURE FEED...THE MORE UNCERTAINTY EXISTS WITH HEAVY RAIN THREAT DEVELOPING ACROSS NORTHERN CWA... ALTHOUGH CANNOT BE RULED OUT IF STORMS CAN WEAKEN TO OUR SOUTH ALLOWING LOW LEVEL JET TO REFOCUS FURTHER NORTH WITH NORTHWARD LIFTING WARM FRONT. HAVE TRENDED FORECASTS TOWARD HEAVIER RAINS TONIGHT ACROSS SOUTHERN HALF OF THE CWA... BUT WILL MAINTAIN FLASH FLOOD WATCH ALL AREAS DUE TO UNCERTAINTY. && .SYNOPSIS... ISSUED AT 330 PM CDT TUE SEP 9 2014 LOW PRESSURE OVER EXTREME SOUTHEAST CO HAD A WARM FRONT EXTENDED INTO NORTHERN MO INTO SOUTHERN IL. TEMPERATURES TO THE SOUTH OF THE FRONT WERE WELL IN THE 80S TO MID 90S WITH DEWPOINTS IN THE LOWER TO MID 70S. SBCAPES OF 4000 J/KG WERE OCCURRING IN WESTERN MO. TO THE NORTH OF THE FRONT IN THE RAIN COOLED AIR READINGS WERE ONLY IN THE UPPER 60S TO UPPER 70S. THE BEST PRESSURE FALLS WERE LOCATED IN WESTERN KS. PRECIPITABLE WATERS WERE AS HIGH AS 1.9 INCHES IN NORTHERN MO. DOPPLER RADAR CONTINUED TO SHOW FESTERING SHOWERS AND A FEW THUNDERSTORMS FROM EASTERN NEB INTO SOUTHEAST IA AND CENTRAL IL WITH WARM AIR ADVECTION INTO THE AREA. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 330 PM CDT TUE SEP 9 2014 HEADLINES...NOW THAT MUCH OF THE AREA HAS SATURATED SOILS THE FLASH FLOOD WATCH WILL CONTINUE TONIGHT INTO WEDNESDAY MORNING FOR THE ENTIRE CWA. TONIGHT...ADDITIONAL RAINFALL OF 1 TO 3 INCHES APPEAR LIKELY. SOME LOCATIONS MAY RECEIVE 4 TO 6 INCHES...ESPECIALLY IN ANY TRAINING/REPEATING STORMS. THIS AMOUNT OF RAIN ON VERY SATURATED SOILS WOULD CAUSE SERIOUS FLASH FLOODING. PRECIPITABLE WATERS WILL BE AT NEAR RECORD VALUES FOR SEPTEMBER...ABOUT 2.2 INCHES. THIS IS DUE TO RICH GULF MOISTURE COMBINED WITH MOISTURE FROM THE REMNANTS OF WHAT WAS MAJOR PACIFIC HURRICANE NORBERT. RAINFALL RATES WILL BE EXTREMELY HIGH SO VERY TORRENTIAL RAINS WILL ACCOMPANY THESE STORMS. CONFIDENCE IS VERY HIGH FOR THIS FLASH FLOOD EVENT BUT IS LOWER FOR THE SEVERE THREAT. THERE IS THE POTENTIAL FOR LOCALIZED WET MICROBURSTS DUE TO THE VERY SATURATED ATMOSPHERE BUT ANY HAIL SHOULD REMAIN BELOW SEVERE LEVELS. I AM CONCERNED FOR THE POTENTIAL FOR AN ISOLATED TORNADO OR TWO ON ANY BOUNDARY AS THE DEEP LAYER SHEAR BECOMES VERY STRONG EVEN WELL AFTER DARK AS THE SURFACE LOW DEEPENS AND TRACKS TOWARDS LA CROSSE WI BY 12Z WEDNESDAY. THE HRRR MESO MODEL SUGGESTS ACTIVITY INCREASING IN OUR SOUTHERN CWA LATE THIS AFTERNOON OR TOWARDS EVENING THEN SPREADING NORTHEAST AS THE EVENING PROGRESSES...WITH WIDESPREAD STORMS THEN OCCURRING OVERNIGHT. SOME OF THE STRONGER STORMS WILL ALSO PRODUCE FREQUENT TO CONTINUOUS DANGEROUS LIGHTNING. MINIMUM TEMPERATURES WILL BE IN THE MID 60S TO LOWER 70S. WEDNESDAY...DEEPENING CYCLONE WILL TRACK INTO THE GREAT LAKES REGION SENDING A STRONG COLD FRONT INTO OUR WESTERN CWA IN THE MORNING AND OUR EASTERN CWA IN THE EARLY AFTERNOON. THE THUNDERSTORMS WILL GRADUALLY DIMINISH AND SHIFT TO THE EAST OF THE CWA WITH THE FRONT. THE SEVERE THREAT APPEARS TO BE FARTHER TO THE EAST THAN EARLIER THOUGHT AND SPC HAS THE SLIGHT RISK ONLY IN OUR FAR SOUTHEAST COUNTIES...BUT THIS WILL DEPEND ON CLOUD COVER AND AMOUNT OF INSTABILITY. MAXIMUM TEMPERATURES SHOULD RANGE FROM THE UPPER 60S AT INDEPENDENCE IA TO THE UPPER 70S IN OUR FAR EAST/SOUTHEAST COUNTIES. .LONG TERM...(WEDNESDAY NIGHT THROUGH NEXT TUESDAY) ISSUED AT 330 PM CDT TUE SEP 9 2014 WEDNESDAY NIGHT THROUGH FRIDAY...SEASONABLY STRONG RIDGE STILL ON TRACK TO DUMP DOWN THE PLAINS AND UPPER MS RVR VALLEY THIS PERIOD. EXPECT MOST POST-FRONTAL RAINS TO BE OUT OF THE CWA AT START OF THE PERIOD...WITH JUST DEEPENING LLVL NORTHERLY FLOW COOL ADVECTING AND SCORING OUT THE CLOUD COVER EVENTUALLY BY THU MORNING. EVEN IF CLOUD COVER HOLDS ON TIL DAYLIGHT...LOWS TO BE ADVECTED DOWN INTO THE 40S IN MOST OF THE CWA. INCOMING CANADIAN AIR TO WARM ONLY INTO THE 60S THU EVEN WITH SOME SUNSHINE...WITH A QUICK DROP OFF AFTER SUNSET THU EVENING INTO THE 40S BEFORE INCREASING CLOUDS AHEAD OF THE NEXT SYSTEM TOWARD FRI MORNING HALTS TEMP DROP OFF. STILL SOME PHASING ISSUES TO BE HAMMERED OUT...BUT LATEST RUN MEDIUM RANGE SOLUTIONS SUGGEST SOME TYPE OF WAVE/POSSIBLY RATHER VIGOROUS...TO ROLL ACRS THE REGION ON FRI. THIS SYSTEM WILL NOT HAVE NEAR THE MOISTURE SOURCE OR THERMODYNAMICS TO WORK WITH AS THE CURRENT SYSTEM...BUT STILL SHOULD INDUCE A RAIN SHIELD THAT WILL OVERSPREAD MOST OF THE CWA FROM WEST TO EAST AS FRI PROGRESSES. CLOUD COVER AND PRECIP TO KEEP A LID ON TEMPS WITH MOST AREAS HELD IN THE 50S OR EVEN UPPER 40S AND NORTH WINDS MAKING FOR A RAW DAY. CURRENT INDICATIONS SUGGEST MOST AREAS TO GET FROM 0.10 UP CLOSE TO HALF AN INCH BY THE TIME THE RAIN PULLS OUT FRI EVENING. MODELS STILL VARYING ON PRECIP AND CLOUD COVER EXIT TIMING LATER FRI NIGHT...BUT WILL JUST KEEP PRECIP IN THE EVENING FOR NOW. POST-WAVE SUBSIDENCE MAY MAKE FOR A LATE NIGHT CLEAR OUT...BUT SOME CHANCE FOR SUBSIDENCE INVERSION TO TRAP CLOUDS INTO SAT MORNING LIMITING FRI NIGHT/SAT MORNING COLD POTENTIAL. THE GFS CONTINUES TO BE THE COLD MODEL WITH SOME UPPER 30S IN THE NORTHWESTERN THIRD OF THE DVN CWA AND LOWER 40S ELSEWHERE. THE ECMWF MORE IN THE WAY OF LOW TO MID 40S BUT KEEPS THE CLOUD COVER AND SOME MIXING SFC WINDS GOING INTO SAT MORNING. WITH EXTENT OF INCOMING UNSEASONABLY COLD AIRMASS...FEEL WITH ANY KIND OF CLEAR OUT/PARTIAL CLEARING AND SFC WIND DROP OFF UNDER 10 MPH LATE FRI NIGHT...THE COOLER GFS WILL PREVAIL. SATURDAY AND SUNDAY...HIGHS ONLY RECOVERING INTO THE UPPER 50S TO MID 60S SAT UNDER WEAK MIXING REGIME OF CANADIAN HIGH PRESSURE... THEN HOW COLD TO GO SAT NIGHT THE CHALLENGE. IF LLVL RETURN FLOW DOES NOT MATERIALIZE IN TIME AND THE SFC RIDGE PERSISTS LONGER BEFORE EASTWARD MIGRATION...SAT NIGHT MAY BE THE COOLER OF THE TWO COLD WINDOW NIGHTS BEING WATCHED RIGHT NOW...MORE IDEAL RADIATIONAL COOLING PARAMETERS IN LINE POSSIBLY. MORE WIDESPREAD MID TO UPPER 30S POSSIBLE ESPECIALLY EAST OF THE MS RVR CLOSER TO RIDGE CENTER. WAA ON BACK SIDE OF RIDGE COMPLEX MAY GENERATE SOME ELEVATED SHOWERS INTO THE WESTERN CWA BY LAT SUNDAY NIGHT...BUT CONFIDENCE LOW ON THAT SCENARIO. MONDAY THROUGH NEXT TUESDAY...NEXT WAVE WILL LOOK TO SHEAR ACRS THE UPPER MIDWEST SOMETIME THIS PERIOD FOR THE NEXT RAIN CHANCE...WITH THE 12Z RUN ECMWF MORE PHASED AN ORGANIZED WITH THIS SYSTEM MON NIGHT INTO TUE FOR MORE SIGNIFICANT PRECIP AS OPPOSED TO THE GFS. ..12.. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1142 PM CDT TUE SEP 9 2014 CONDITIONS TO CONTINUE DETERIORATING TO WIDESPREAD MVFR WITH AREAS OF IFR IN LOW CLOUDS OVERNIGHT WITH OCCASIONAL RAIN... AND SOME STORMS MAINLY SOUTH OF I-80. WINDS OVERNIGHT WILL BE FROM THE EAST AND SOUTHEAST AROUND 10 KTS AND GUSTY. STRONG COLD FRONT WILL PASS THROUGH THE TERMINALS FROM MID AM THROUGH EARLY PM ON WED WITH SHIFT TO GUSTY NORTHWEST WINDS. PCPN TO DIMINISH WITH FRONTAL PASSAGE WITH LINGERING MVFR TO AREAS OF IFR CIGS LIKELY LIFTING TO VFR AND SCATTERING OUT LATE PM AND EVE WITH INCOMING SUBSIDENCE. && .HYDROLOGY... THE RIVER WATCH WILL BE ON THROUGH MID WEEK. AFTER LAST NIGHT/S AND THIS MORNINGS RAINS...ANOTHER 1-4 INCHES TONIGHT INTO WED MORNING WILL DEFINITELY PRODUCE SOME FLOODING ON AREA TRIBUTARIES...DEPENDING ON HOW WIDESPREAD THE ADDITIONAL HEAVY RAIN WILL FALL IN THE LOCAL AREA OF CONCERN. RIVER BASINS TO WATCH FOR FLOODING POTENTIAL ON SOME OF THE FCST POINTS FROM WED THROUGH FRI MORNING ARE THE SKUNK... CEDAR...IOWA...WAPSI...ENGLISH...AND DES MOINES RIVERS. THE MAQUOKETA MAY GET CLOSE. IF NOT FLOODING THEN SIGNIFICANT WITHIN BANK RISES TO OCCUR. ..12.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...FLASH FLOOD WATCH UNTIL 7 AM CDT WEDNESDAY FOR BENTON-BUCHANAN- CEDAR-CLINTON-DELAWARE-DES MOINES-DUBUQUE-HENRY IA-IOWA- JACKSON-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA- MUSCATINE-SCOTT-VAN BUREN-WASHINGTON. IL...FLASH FLOOD WATCH UNTIL 9 AM CDT WEDNESDAY FOR BUREAU-CARROLL- HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-MERCER- PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE. MO...FLASH FLOOD WATCH UNTIL 7 AM CDT WEDNESDAY FOR CLARK-SCOTLAND. && $$ UPDATE...05 SYNOPSIS...HAASE SHORT TERM...HAASE LONG TERM...12 AVIATION...05 HYDROLOGY...12
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
215 AM CDT WED SEP 10 2014 ...UPDATE TO LONG TERM... .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 204 PM CDT TUE SEP 9 2014 LATEST RAP 400MB POTENTIAL VORTICITY APPEARS TO HAVE A DECENT HANDLE WITH AN UPPER LEVEL DISTURBANCE THAT WAS CROSSING THE COLORADO ROCKIES AT 18Z. GIVEN THE 18Z VERIFICATION WILL STAY CLOSE TO THE RAP ON TIMING OF THIS UPPER LEVEL FEATURE AS IT CROSSES EASTERN COLORADO AND WESTERN KANSAS LATER THIS EVENING. GIVEN LATE DAY INSTABILITY AND LOCATION OF LOW LEVEL FORCING AHEAD OF THIS UPPER LEVEL TROUGH NEAR A SURFACE BOUNDARY THAT WILL EXTEND FROM SOUTHEAST COLORADO INTO NORTH CENTRAL KANSAS THERE WILL BE A CHANCE FOR SCATTERED THUNDERSTORMS LATE THIS AFTERNOON ACROSS NORTH CENTRAL KANSAS AND PORTIONS OF WEST KANSAS. BASED ON THE 21Z TUESDAY AND 00Z WEDNESDAY CAPE AND 0-6KM SHEAR FROM THE NAM A FEW STORMS LATE TODAY MAY BE SEVERE WITH THE AREA MORE FAVORABLE FOR HAIL GOLF BALL SIZE OR LARGER ALONG WITH WIND GUST IN EXCESS OF 60 MPH WILL BE ALONG AND NORTH OF A DIGHTON AND LARNED LINE. THUNDERSTORMS WILL THEN INCREASE IN AREAL COVERAGE EARLY TONIGHT AS THE UPPER LEVEL DISTURBANCE CROSSES THE CENTRAL HIGH PLAINS AND A SURFACE BOUNDARY MOVES ACROSS SOUTHWEST KANSAS. THE AREA THAT WILL BE MORE FAVORABLE FOR WIDESPREAD THUNDERSTORMS EARLY TONIGHT WILL BE ALONG AND NORTH OF A 700MB +10C TO +13C BAROCLINIC ZONE. GIVEN THE 12Z NAM AND 12Z GFS THIS FAVORABLE AREA WILL BE NORTHEAST OF A SYRACUSE TO DODGE CITY THE PRATT LINE. ALSO GIVEN THE HIGH PRECIPITABLE WATER VALUES PERIODS THERE WILL BE A CHANCE FOR PERIODS OF HEAVY RAIN IN THIS AREA AS WELL. BUFR SOUNDINGS INDICATING WINDS NEAR THE SURFACE BEHIND THE COLD FRONT WILL RANGE FROM 20 TO 30 KNOTS AS THE LOWER LEVELS BEGIN TO SATURATE. BY 12Z WEDNESDAY THE DEPTH OF THIS LOW LEVEL MOISTURE APPROACHES 3000FT WHICH SUPPORTS INSERTING A SLIGHT CHANCE FOR LIGHT DRIZZLE FOR SEVERAL HOURS EARLY WEDNESDAY MORNING. BY LATE MORNING THIS LOW LEVEL MOISTURE WILL BEGIN TO ERODE FROM SOUTHWEST NORTHEAST AND GIVEN SOME AFTERNOON SUNSHINE ACROSS SOUTHWEST AND SOUTH CENTRAL KANSAS THE HIGHS ARE EXPECTED TO CLIMB BACK INTO THE MID 70S BASED ON THE 00Z THURSDAY 850MB TEMPERATURES. FURTHER NORTH, NEAR THE INTERSTATE 70 CORRIDOR THE CLOUDS AND 850MB TEMPERATURES AT 00Z THURSDAY SUGGEST HIGHS ON IN THE UPPER 60S TO NEAR 70. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 215 AM CDT WED SEP 10 2014 ON THURSDAY, SFC CYCLOGENESIS WILL INCREASE ACROSS SOUTHEASTERN COLORADO. THERE WILL BE A FAIRLY TIGHT TEMPERATURE GRADIENT AHEAD OF AN APPROACHING COLD FRONT. CALLING FOR MID 60S ALONG THE INTERSTATE 70 CORRIDOR TO MID 70S NEAR THE OKLAHOMA BORDER. NO PRECIPITATION IS EXPECTED UNTIL LATE EVENING. A STRONG FRONT IS FORECAST TO MOVE ACROSS WESTERN KANSAS AROUND 06Z AND TOTALLY CLEARING THE FORECAST AREA BY 12Z FRIDAY. THIS FRONT HAS CONSIDERABLE COLD AIR ADVECTION BEHIND IT WITH THE 850-HPA 0C ISOTHERM FLIRTING WITH THE NORTHERN COUNTIES. THE WESTERN COUNTIES (GCK AND WEST) STAND TO SEE THE MOST PRECIPITATION OF HALF OF AN INCH TO 1 INCH. FARTHER EAST, LESS AMOUNTS ARE FORECAST AND EXPECTED. TEMPERATURES WILL STRUGGLE TO GET OUT OF THE 50S AND CONSIDERABLE CLOUD COVER IS EXPECTED THROUGH THE MAJORITY OF THE DAY. IT WILL FEEL VERY FALL-LIKE FRIDAY. SURFACE HIGH PRESSURE WILL RIDGE OVER THE AREA SATURDAY MORNING WITH THE COLDEST TEMPERATURES FORECAST OF THE SEASON SO FAR. FORECAST UPPER 30S ALONG AND NORTH OF HIGHWAY 96. THERE COULD BE SOME PATCHY FROST TOO. GOOD NEWS IF YOU ARE A FAN OF WARM TEMPERATURES. THE COOL SPELL WON`T LAST LONG AND LOW LEVEL WARM AIR ADVECTION WILL BEGIN SATURDAY WITH 70S RETURNING TO THE AREA. RELATIVELY TRANQUIL WEATHER WILL CONTINUE THROUGH THE REST OF THE PERIOD. A FRONT MAY SPARK A FEW SHOWERS AND/OR STORMS MONDAY AND TUESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1222 AM CDT WED SEP 10 2014 A COLD FRONT WILL CONTINUE TO SLIP SOUTH ACROSS WESTERN KANSAS THROUGH THE EARLY MORNING HOURS. MVFR TO IFR STRATUS CURRENTLY OVER SOUTHERN NEBRASKA IS EXPECTED TO CONTINUE BUILDING SOUTH THROUGH THE EARLY MORNING HOURS AND SHOULD MOVE INTO THE TAF SITES BY AROUND 10-12Z. THE STRATUS SHOULD LAST THROUGH MUCH OF THE MORNING BEFORE LIFTING AT GARDEN CITY AND DODGE CITY BY EARLY AFTERNOON. THE HAYS AREA MAY SEE AT LEAST MVFR CEILINGS THROUGH THE PERIOD. VFR CONDITIONS ARE EXPECTED THROUGH THE REMAINDER OF THE FORECAST PERIOD AT GARDEN CITY AND DODGE CITY ALTHOUGH THERE IS SOME POTENTIAL FOR LOW CEILINGS TO REDEVELOP AT THOSE SITES BY THE END OF THE FORECAST PERIOD. && .PRELIMINARY POINT TEMPS/POPS... DDC 73 51 70 45 / 20 0 10 70 GCK 73 50 72 42 / 20 0 20 80 EHA 75 53 75 46 / 10 0 20 80 LBL 76 53 74 48 / 10 0 10 70 HYS 68 49 63 42 / 20 0 20 70 P28 78 55 74 51 / 10 0 10 60 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BURGERT LONG TERM...SUGDEN AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1222 AM CDT WED SEP 10 2014 ...UPDATED AVIATION DISCUSSION... .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 204 PM CDT TUE SEP 9 2014 LATEST RAP 400MB POTENTIAL VORTICITY APPEARS TO HAVE A DECENT HANDLE WITH AN UPPER LEVEL DISTURBANCE THAT WAS CROSSING THE COLORADO ROCKIES AT 18Z. GIVEN THE 18Z VERIFICATION WILL STAY CLOSE TO THE RAP ON TIMING OF THIS UPPER LEVEL FEATURE AS IT CROSSES EASTERN COLORADO AND WESTERN KANSAS LATER THIS EVENING. GIVEN LATE DAY INSTABILITY AND LOCATION OF LOW LEVEL FORCING AHEAD OF THIS UPPER LEVEL TROUGH NEAR A SURFACE BOUNDARY THAT WILL EXTEND FROM SOUTHEAST COLORADO INTO NORTH CENTRAL KANSAS THERE WILL BE A CHANCE FOR SCATTERED THUNDERSTORMS LATE THIS AFTERNOON ACROSS NORTH CENTRAL KANSAS AND PORTIONS OF WEST KANSAS. BASED ON THE 21Z TUESDAY AND 00Z WEDNESDAY CAPE AND 0-6KM SHEAR FROM THE NAM A FEW STORMS LATE TODAY MAY BE SEVERE WITH THE AREA MORE FAVORABLE FOR HAIL GOLF BALL SIZE OR LARGER ALONG WITH WIND GUST IN EXCESS OF 60 MPH WILL BE ALONG AND NORTH OF A DIGHTON AND LARNED LINE. THUNDERSTORMS WILL THEN INCREASE IN AREAL COVERAGE EARLY TONIGHT AS THE UPPER LEVEL DISTURBANCE CROSSES THE CENTRAL HIGH PLAINS AND A SURFACE BOUNDARY MOVES ACROSS SOUTHWEST KANSAS. THE AREA THAT WILL BE MORE FAVORABLE FOR WIDESPREAD THUNDERSTORMS EARLY TONIGHT WILL BE ALONG AND NORTH OF A 700MB +10C TO +13C BAROCLINIC ZONE. GIVEN THE 12Z NAM AND 12Z GFS THIS FAVORABLE AREA WILL BE NORTHEAST OF A SYRACUSE TO DODGE CITY THE PRATT LINE. ALSO GIVEN THE HIGH PRECIPITABLE WATER VALUES PERIODS THERE WILL BE A CHANCE FOR PERIODS OF HEAVY RAIN IN THIS AREA AS WELL. BUFR SOUNDINGS INDICATING WINDS NEAR THE SURFACE BEHIND THE COLD FRONT WILL RANGE FROM 20 TO 30 KNOTS AS THE LOWER LEVELS BEGIN TO SATURATE. BY 12Z WEDNESDAY THE DEPTH OF THIS LOW LEVEL MOISTURE APPROACHES 3000FT WHICH SUPPORTS INSERTING A SLIGHT CHANCE FOR LIGHT DRIZZLE FOR SEVERAL HOURS EARLY WEDNESDAY MORNING. BY LATE MORNING THIS LOW LEVEL MOISTURE WILL BEGIN TO ERODE FROM SOUTHWEST NORTHEAST AND GIVEN SOME AFTERNOON SUNSHINE ACROSS SOUTHWEST AND SOUTH CENTRAL KANSAS THE HIGHS ARE EXPECTED TO CLIMB BACK INTO THE MID 70S BASED ON THE 00Z THURSDAY 850MB TEMPERATURES. FURTHER NORTH, NEAR THE INTERSTATE 70 CORRIDOR THE CLOUDS AND 850MB TEMPERATURES AT 00Z THURSDAY SUGGEST HIGHS ON IN THE UPPER 60S TO NEAR 70. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 313 PM CDT TUE SEP 9 2014 THE TREND WILL BE FOR COOLER AND WETTER IN THE VERY EARLY PERIOD OF THE LONG TERM FORECAST. THE PERIOD FROM WEDNESDAY INTO THE BEGINNING OF THE WEEKEND WILL THEN BE FOLLOWED BY A MODERATE REBOUND BACK TOWARD THE 80S BY THE MIDDLE OF NEXT WEEK. ALL THREE MODELS, THE ECMWF, GFS AND NAM INDICATED PRECIPITATION ALONG A STRONG FRONTOGENETIC ZONE ACROSS CENTRAL AND FAR WESTERN KANSAS INTO SOUTHEAST COLORADO FROM LATE THURSDAY NIGHT AND SPREADING EAST OVER CENTRAL KANSAS FRIDAY MORNING. SOME VARIABILITY IS EXPECTED AS THE BETTER FORCING IN THE MID LEVELS IS NOT EXPECTED TO SLIDE ALL THE WAY THROUGH THE CWA INTO OKLAHOMA, HENCE A BAND OF HIGHER RAIN AMOUNTS COULD FALL SOMEWHERE FROM THE HIGHWAY 54 CORRIDOR NORTHWARD AS THE NAM SUGGESTS. OTHER LOCATIONS SHOULD STILL GET SOME, BUT GENERALLY MUCH LIGHTER PRECIPITATION AMOUNTS OF A FEW HUNDREDTHS AS THE SECONDARY FRONTAL BOUNDARY MOVES THROUGH THE REGION IN THE FORM OF SCATTERED SHOWERS IF NOT A PERIOD OF RAIN. OF MUCH LONGER DURATION AND IMPACT WILL BE THE WIDESPREAD STRATUS THROUGH THE AREA, INHIBITING INSOLATION AND ENHANCING COLD ADVECTION. THE NUMEROUS MODELS AND BLEND SOLUTIONS STRONGLY SUPPORTS LOW 50S ACROSS MUCH OF THE AREA FOR A HIGH TEMPERATURES ON FRIDAY. TEMPERATURES THIS COOL WILL REPRESENT ONLY A FEW DEGREES ABOVE RECORD MIN-MAXIMUM TEMPERATURES FOR SEPTEMBER 12TH AT LEAST LOCALLY AT DDC. A WARMING TEND WILL BE SLOW THROUGH THE WEEKEND PERIOD. THE MEAN LAYER WILL RETURN TO GENERALLY ZONAL PATTERN BY SUNDAY AFTER THE LARGE WAVE EXISTS. THE NEXT WAVE WILL NOT BECOME A POTENTIAL IMPACT UNTIL AROUND LATE SUNDAY OR MONDAY. THE PATTERN SUGGEST SOUTHWEST KANSAS COULD BE SPLIT AS FAR AS UPPER DYNAMIC FORCING GOES, WITH POSSIBLE MCS ACTIVITY TO THE NORTH IN THE DAKOTA`S AND NEBRASKA AND SHORTWAVE ENERGY IN THE PANHANDLES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1222 AM CDT WED SEP 10 2014 A COLD FRONT WILL CONTINUE TO SLIP SOUTH ACROSS WESTERN KANSAS THROUGH THE EARLY MORNING HOURS. MVFR TO IFR STRATUS CURRENTLY OVER SOUTHERN NEBRASKA IS EXPECTED TO CONTINUE BUILDING SOUTH THROUGH THE EARLY MORNING HOURS AND SHOULD MOVE INTO THE TAF SITES BY AROUND 10-12Z. THE STRATUS SHOULD LAST THROUGH MUCH OF THE MORNING BEFORE LIFTING AT GARDEN CITY AND DODGE CITY BY EARLY AFTERNOON. THE HAYS AREA MAY SEE AT LEAST MVFR CEILINGS THROUGH THE PERIOD. VFR CONDITIONS ARE EXPECTED THROUGH THE REMAINDER OF THE FORECAST PERIOD AT GARDEN CITY AND DODGE CITY ALTHOUGH THERE IS SOME POTENTIAL FOR LOW CEILINGS TO REDEVELOP AT THOSE SITES BY THE END OF THE FORECAST PERIOD. && .PRELIMINARY POINT TEMPS/POPS... DDC 49 65 45 53 / 0 10 60 60 GCK 49 63 43 52 / 10 10 80 70 EHA 52 69 44 54 / 10 10 80 70 LBL 51 67 47 55 / 0 10 80 70 HYS 45 62 43 53 / 0 10 50 60 P28 53 71 54 59 / 0 10 40 70 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BURGERT LONG TERM...RUSSELL AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
602 AM EDT WED SEP 10 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 533 AM EDT WED SEP 10 2014 LIGHT TO AT TIME HEAVY RAIN CONTINUES TO FALL OVER THE W THIRD OF UPPER MI THIS MORNING...ASSOCIATED WITH THE SFC TROUGH THAT PUSHED OVERHEAD EARLY THIS MORNING THE 500MB SHORTWAVE CROSSING WI...AND THE DEEPENING SFC LOW RIDING UP ALONG THE TROUGH NEARING FROM IA. THE LATEST SATELLITE AND RUC ANALYSIS SHOWS THIS INITIAL N SWATH OF MOISTURE EJECTING NE ACROSS THE CWA...WITH THE EFFECTS OF THE SW TO NE 100KT 250MB JET NEARING FROM THE PLAINS. THE SECONDARY AREA OF CLOUDS WILL BE IMPACTING THE E HALF OF THE CWA LATER THIS MORNING AND INTO THE AFTERNOON HOURS. EXACT RAINFALL TOTALS REMAIN TRICKY AS THERE ARE 2 AREAS OF THOUGHT. THE LATEST 06Z NAM PAINTS AN ADDITIONAL 1-2IN OVER CENTRAL AND E UPPER MI LATE THIS MORNING THROUGH EARLY THIS AFTERNOON. HOWEVER...THE 00Z GFS IS PUSHING MUCH OF THE MOISTURE JUST TO OUR E. HAVE GONE WITH A MIDDLE OF THE ROAD SOLUTION FOR THE MOMENT...KNOWING THAT CONVECTION TO THE SOUTH COULD STILL HURT THE INFLOW OF MOISTURE UP OUR WAY. STILL...ADDITIONAL SHOWERS CROSSING THE CWA THIS AFTERNOON WITH BE FACED WITH STIFF N ONSHORE FLOW...RESULTING IN A SLOWER N PROGRESSION AND OVERALL UPSLOPE ENHANCEMENT. SEE THE HYDROLOGY SECTION FOR MORE DETAILS ABOUT PRECIPITATION FOR THE REST OF TODAY. RAIN/RAIN SHOWERS WILL CONTINUE THROUGH TONIGHT...MAINLY ACROSS THOSE UPSLOPE AREAS OF CENTRAL UPPER MI. ADDITIONAL RAINFALL MAY ADD UP TO 0.25IN OR MORE ACROSS THE HURON MOUNTAINS. FCST MODELS ARE CONTINUING TO GO WITH THE SFC LOW TRACKING ACROSS N LOWER MI LATE THIS AFTERNOON...BEFORE EXITING INTO S ONTARIO AND W QUEBEC LATE THIS EVENING. TEMPERATURES WILL REMAIN TRICKY...AS THEY FALL W AND STILL RISE A COUPLE OF DEGREES AFTER SUNRISE E. KEPT THE WIND FCST VERY SIMILAR TO THE LAST COUPLE OF DAYS...WITH N-NNW GUSTS NEARING 35KTS FROM AROUND 18Z TODAY TO 08Z TONIGHT. AN SPS MAY BE NEEDED FOR THE W HALF AND HIGHER TERRAIN OF THE KEWEENAW PENINSULA...OR LOW END WIND ADVISORY TO HIGHLIGHT THE STRONG WINDS ON TOP OF SATURATED SOILS THAT MAY MORE EASILY UPROOT TREES THANKS TO THE ABUNDANT LEAVES. AS FOR THE OVERNIGHT HOURS...EXPECT SLOWLY DIMINISHING WINDS LATE AND COLD AIR TO FILTER IN WITH 850MB TEMPS OF -2 TO +4C BY DAYBREAK THURSDAY. DEPENDING ON HOW FAST RAIN CAN GET OUT OF THE INTERIOR AREAS ALONG THE WI BORDER...MID 30S LOWS WILL NOT BE OUT OF THE QUESTION. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 359 AM EDT WED SEP 10 2014 MAIN FCST CONCERNS IN THE LONG TERM FOCUS ON HOW QUICKLY ON THU CLDS AND SHOWERS ASSOCIATED WITH THE WED LO PRES WL EXIT THE CWA...TEMPS AND THE POTENTIAL FOR FROST ON THU NGT AND THEN ON POPS ACCOMPANYING THE PASSAGE OF ANOTHER DISTURBANCE THRU THE LOWER LKS ON FRI INTO SAT. SINCE AN UPR TROF WL DOMINATE ERN NAMERICA THRU NEXT WEEK... EXPECT BLO NORMAL TEMPS TO PREVAIL DURING THE EXTENDED PERIOD. THU...AS DEPARTING LO PRES OVER FAR SW QUEBEC AT 12Z THU SHIFTS TO THE ENE...STEADY N LLVL FLOW IS PROGGED TO WEAKEN AND BECOME MORE ACYC UNDER GENERAL DEEP LYR QVECTOR DVGC LEFT IN THE WAKE OF THE EXITING SHRTWV AND RDG AXIS EXPANDING TO THE E OF SFC HI CENTER IN THE NRN PLAINS. EXPECT PLENTY OF CLDS IN THE MRNG WITH SHOWERS MAINLY NEAR LK SUP ASSOCIATED WITH CHILLY LINGERING CYC FLOW OVER THE RELATIVELY WARM LK SUP WATERS. BUT WITH INCRSG SUBSIDENCE/ACYC FLOW IN THE PRESENCE OF DAYTIME HEATING...EXPECT THE SHOWERS TO DIMINISH AND THE CLD PATTERN TO SHIFT TO MORE INLAND SC COVERAGE UNDER THE H85 THERMAL TROF AND SUBSIDENCE INVRN SINKING TOWARD H85-9. H85 TEMPS IN THE ZERO TO -2C RANGE WL SUPPORT WELL BLO NORMAL HI TEMPS MAINLY IN THE UPR 40S/50S...COOLEST OVER THE HIER TERRAIN OF THE NW HALF. THU NGT...UNDER BLDG HI PRES WITH LOSS OF DAYTIME HEATING...EXPECT LINGERING SC TO DSPT IN THE EVNG AND GIVE WAY TO AT LEAST A PERIOD OF MOCLR SKIES AND LGT WINDS. WITH PWAT UNDER 0.5 INCH...TEMPS SHOULD FALL OFF STEADILY. THE ONE LIMITING FACTOR WL BE HOW QUICKLY HI CLDS IN ADVANCE OF SHRTWV MOVING THRU THE NRN PLAINS WL INVADE THE UPR LKS. SUSPECT THE COLD SPOTS OVER THE INTERIOR WL SEE TEMPS FALLING AOB 32...BUT WL HOLD OFF ON ANY KIND OF FREEZE WATCH/FROST HEADLINE GIVEN ACTIVE SHORT TERM...MARGINALLY LO ENUF FCST TEMPS AND COVERAGE OF THOSE REALLY LO TEMPS UNDER SOME INCRSG HI CLDS. FRI THRU SAT...ALTHOUGH THERE IS GOOD MODEL AGREEMENT ON THE TIMING AND TRACK OF A FAIRLY VIGOROUS SHRTWV THAT IS FCST TO MOVE E FM THE NRN ROCKIES ON THU AFTN THRU THE NCENTRAL PLAINS AND ACROSS THE LOWER LKS FRI NGT/SAT...THERE ARE SOME FAIRLY LARGE DIFFERENCES IN THE MSLP FIELDS AND QPF. THE 09/12Z ECWMF CONTINUES TO BE THE MODEL THAT SHOWS THE MORE IMPRESSIVE PRES FALL. WITH A DEEPER SFC REFLECTION...THE ECMWF ALSO SHOWS MORE EXPANSIVE MID LVL MSTR/PCPN EXTENDING INTO ALL OF UPR MI DURING FRI NGT/SAT MRNG. GIVEN THE POSITIVE TILT TO THE SHRTWV....EXPANSIVE HI PRES THAT IS FCST TO EXTEND FM THE NRN PLAINS INTO THE UPR LKS IN ADVANCE OF THIS SHRTWV AND DRY/STABLE NATURE OF THE ANTECEDENT AIRMASS /PWAT AOB 0.5 INCH WITH STRONG SUBSIDENCE INVRN BTWN H8-7/...SUSPECT THE NON-ECMWF MODELS SHOWING LESS SFC RESPONSE ARE ON THE RIGHT TRACK. HAVE THUS CHOSEN TO MAINTAIN ONLY LO CHC POPS...HIEST OVER THE SRN CWA CLOSER TO THE SHRTWV TRACK/AREA OF SHARPER DEEP LYR QVECTOR CNVGC. THICKER CLDS/THESE POPS WL ARRIVE ON FRI AFTN AS THE DISTURBANCE SLIDES INTO THE UPR MS RIVER VALLEY. ONCE THE SHRTWV PUSHES TO THE E ON SAT MRNG...TRAILING SHRTWV RDG/DRIER AIRMASS WL BRING A RETURN TO DRY WX/CLRG. WITH H85 TEMPS IN THE ZERO TO -2C RANGE DURING THIS TIME...THE WX WL BE UNSEASONABLY COOL. IF SKIES CLR FAST ENUF LATE FRI NGT...NOT OUT OF THE QUESTION THERE COULD BE SOME FROST OVER THE INTERIOR W ARND SUNRISE ON SAT. EXTENDED...AFTER A DRY PERIOD ASSOCIATED WITH SFC HI PRES PASSING THRU THE LOWER LKS ON SAT NGT...ANOTHER CNDN SHRTWV DIGGING THRU THE MEAN UPR TROF CENTERED OVER HUDSON BAY AND INTO THE NCENTRAL CONUS WL BRING A CHC OF MORE SHOWERS FOR SUN THRU MON. THIS DISTURBANCE WL BE MSTR DEPRIVED...SO NO HEAVY RA IS LIKELY. HI PRES MOVING E UNDER THE RISING HGTS IN THE WAKE OF THIS DISTURBANCE SHOULD BRING A RETURN OF DRY WX FOR TUE. WITH THE MEAN TROF IN PLACE...TEMPS ACRS UPR MI WL AVG BLO NORMAL DURING THIS TIME. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 603 AM EDT WED SEP 10 2014 OFF AND ON RAIN AND BR/FG HAVE BEEN THE TREND OVERNIGHT. ONCE THE RAIN HAS ENDED IFR TO VLIFR CEILINGS HAVE DEVELOPED. INCREASING WINDS THIS MORNING SHOULD HELP LIMITED THE BR. HOWEVER...LOW CEILINGS WILL STILL BE POSSIBLE WITH ANY MODERATE RAIN THAT DEVELOPS. LOOKING AT UPSTREAM CONDITIONS...LIFR CEILINGS WILL LIKELY DOMINATE THE DAY AT IWD AND CMX. STEADIER RAIN WILL MOVE INTO SAW OVER THE NEXT FEW HOURS. LOOK FOR STRONG WINDS DEVELOPING W TO E THIS MORNING...WITH GUSTS OVER 30KTS POSSIBLE AT CMX FROM 19Z THIS AFTERNOON TO 04Z THURSDAY. IWD MAY BE LIMITED TO GUSTS AROUND 20KTS...WHILE THE N WINDS GUST BETWEEN 25 AND 30KTS FROM 21Z TO 09Z THURSDAY AT SAW AND KEEP LAKE EFFECT/ENHANCED RAIN SHOWERS GOING THROUGH 12Z THURSDAY. DRIER AIR WILL SLOWLY WORK IN FROM THE W...WITH ONLY A CHANCE OF SHOWERS AT CMX AND IWD BY DAYBREAK THURSDAY. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 359 AM EDT WED SEP 10 2014 AS A DEEP LO PRES MOVES NE THRU THE UPPER MIDWEST AND ACROSS NORTHERN LOWER MI THIS EVENING ON ITS WAY INTO SE CANADA TONIGHT...THE NE GALES AFFECTING WESTERN LAKE SUPERIOR WILL SPREAD E OVER THE REST OF THE LAKE. EXPECT NNE GALES AS HI AS 40-45 KTS TODAY INTO TONIGHT BEFORE THE LO PRES SHIFTS FAR ENOUGH TO THE E AND THE GALES DIMINISH W TO E TONIGHT. AS HI PRES BUILDS TOWARD LAKE SUPERIOR FROM THE PLAINS ON THU...LINGERING N WINDS UP TO 25-30 KTS IN THE MORNING WILL DIMINISH W-E TO UNDER 15-20 KTS BY THE EVENING. RELATIVELY LIGHT WINDS UNDER 20 KTS WILL THEN DOMINATE THRU THE WEEKEND UNDER A RELATIVELY WEAK PRES GRADIENT. && .HYDROLOGY... ISSUED AT 426 AM EDT WED SEP 10 2014 RAINFALL OVER THE W THIRD OF UPPER MI HAS BEEN CONVECTIVELY ENHANCED...WITH RAINFALL RATES BRIEFLY RISING TO NEAR 6IN PER HOUR. WITH THE QUICK MOVEMENT TO THE N JUST OVER 20KTS THAT AMOUNT WAS NOT REALIZED. RADAR ESTIMATES THROUGH 08Z HAVE THE HIGHEST AMOUNTS OVER NW GOGEBIC AND ALONG THE E ONTONAGON/W HOUGHTON COUNTIES...WITH 1.5 TO 2.25IN. SOME LOCAL RIVERS CONTINUE TO RESPOND TO THE RAINFALL A FEW DAYS AGO...AND ARE RISING AT AN INCREASED RATE DO TO THE CURRENT RAIN. SPECIFICALLY THIS INCLUDES THE SOUTH BRANCH OF THE ONTONAGON RIVER AT EWEN /WHICH GIVEN THE TREND WILL SEE A SLOW RISE FOR THE NEXT SEVERAL DAYS/. THE MIDDLE BRANCH OF THE ONTONAGON RIVER AT PAULDING IS ALSO SLOWLY ON THE RISE. OTHERWISE AN AVERAGED 0.5IN HAS FALLEN W OF A LINE FROM IRON RIVER TO BARAGA. LITTLE RAIN HAS FALLEN E OF THIS LINE...WHICH WILL CHANGE OVER THE NEXT COUPLE OF HRS AS ADDITIONAL SHOWERS NEAR FROM WI. THUNDERSTORMS ARE MINIMAL OVER WI...AND PRECIP IS SLOWER THAN ORIGINALLY ANTICIPATED. HAVE BACKED OFF ON THE STORM TOTAL PRECIP OVER THE E THIRD OF THE FCST AREA AS A RESULT. EXPECT THE TRADITIONAL URBAN/SMALL STREAM FLOODING TO BE A SIGNIFICANT POSSIBILITY IN THE TYPICAL POOR DRAINAGE AREAS OF ESC IF A PERIOD OF HEAVIER DOWNPOURS DEVELOP WITH RAINFALL RATES CLOSE TO AN 0.5-1.0 INCH PER HOUR. N CNTRL UPPER MI WILL STILL LIKELY SEE SOME UPSLOPE LAKE ENHANCEMENT TODAY-TONIGHT. THE FLOOD WATCH REMAINS POSTED FOR MUCH OF W AND CENTRAL UPPER MI FOR TODAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... FLOOD WATCH THROUGH THIS EVENING FOR MIZ001>006-009>013-084. LAKE SUPERIOR... GALE WARNING FROM 8 PM THIS EVENING TO 8 AM EDT THURSDAY FOR LSZ251-267. GALE WARNING FROM 2 PM THIS AFTERNOON TO 5 AM EDT THURSDAY FOR LSZ246>250-265-266. GALE WARNING UNTIL 4 AM EDT THURSDAY FOR LSZ243>245-264. GALE WARNING UNTIL 2 AM EDT /1 AM CDT/ THURSDAY FOR LSZ240>242- 263. GALE WARNING UNTIL 11 PM EDT /10 PM CDT/ THIS EVENING FOR LSZ162. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KF LONG TERM...KC AVIATION...KF MARINE...KC HYDROLOGY...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
534 AM EDT WED SEP 10 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 533 AM EDT WED SEP 10 2014 LIGHT TO AT TIME HEAVY RAIN CONTINUES TO FALL OVER THE W THIRD OF UPPER MI THIS MORNING...ASSOCIATED WITH THE SFC TROUGH THAT PUSHED OVERHEAD EARLY THIS MORNING THE 500MB SHORTWAVE CROSSING WI...AND THE DEEPENING SFC LOW RIDING UP ALONG THE TROUGH NEARING FROM IA. THE LATEST SATELLITE AND RUC ANALYSIS SHOWS THIS INITIAL N SWATH OF MOISTURE EJECTING NE ACROSS THE CWA...WITH THE EFFECTS OF THE SW TO NE 100KT 250MB JET NEARING FROM THE PLAINS. THE SECONDARY AREA OF CLOUDS WILL BE IMPACTING THE E HALF OF THE CWA LATER THIS MORNING AND INTO THE AFTERNOON HOURS. EXACT RAINFALL TOTALS REMAIN TRICKY AS THERE ARE 2 AREAS OF THOUGHT. THE LATEST 06Z NAM PAINTS AN ADDITIONAL 1-2IN OVER CENTRAL AND E UPPER MI LATE THIS MORNING THROUGH EARLY THIS AFTERNOON. HOWEVER...THE 00Z GFS IS PUSHING MUCH OF THE MOISTURE JUST TO OUR E. HAVE GONE WITH A MIDDLE OF THE ROAD SOLUTION FOR THE MOMENT...KNOWING THAT CONVECTION TO THE SOUTH COULD STILL HURT THE INFLOW OF MOISTURE UP OUR WAY. STILL...ADDITIONAL SHOWERS CROSSING THE CWA THIS AFTERNOON WITH BE FACED WITH STIFF N ONSHORE FLOW...RESULTING IN A SLOWER N PROGRESSION AND OVERALL UPSLOPE ENHANCEMENT. SEE THE HYDROLOGY SECTION FOR MORE DETAILS ABOUT PRECIPITATION FOR THE REST OF TODAY. RAIN/RAIN SHOWERS WILL CONTINUE THROUGH TONIGHT...MAINLY ACROSS THOSE UPSLOPE AREAS OF CENTRAL UPPER MI. ADDITIONAL RAINFALL MAY ADD UP TO 0.25IN OR MORE ACROSS THE HURON MOUNTAINS. FCST MODELS ARE CONTINUING TO GO WITH THE SFC LOW TRACKING ACROSS N LOWER MI LATE THIS AFTERNOON...BEFORE EXITING INTO S ONTARIO AND W QUEBEC LATE THIS EVENING. TEMPERATURES WILL REMAIN TRICKY...AS THEY FALL W AND STILL RISE A COUPLE OF DEGREES AFTER SUNRISE E. KEPT THE WIND FCST VERY SIMILAR TO THE LAST COUPLE OF DAYS...WITH N-NNW GUSTS NEARING 35KTS FROM AROUND 18Z TODAY TO 08Z TONIGHT. AN SPS MAY BE NEEDED FOR THE W HALF AND HIGHER TERRAIN OF THE KEWEENAW PENINSULA...OR LOW END WIND ADVISORY TO HIGHLIGHT THE STRONG WINDS ON TOP OF SATURATED SOILS THAT MAY MORE EASILY UPROOT TREES THANKS TO THE ABUNDANT LEAVES. AS FOR THE OVERNIGHT HOURS...EXPECT SLOWLY DIMINISHING WINDS LATE AND COLD AIR TO FILTER IN WITH 850MB TEMPS OF -2 TO +4C BY DAYBREAK THURSDAY. DEPENDING ON HOW FAST RAIN CAN GET OUT OF THE INTERIOR AREAS ALONG THE WI BORDER...MID 30S LOWS WILL NOT BE OUT OF THE QUESTION. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 359 AM EDT WED SEP 10 2014 MAIN FCST CONCERNS IN THE LONG TERM FOCUS ON HOW QUICKLY ON THU CLDS AND SHOWERS ASSOCIATED WITH THE WED LO PRES WL EXIT THE CWA...TEMPS AND THE POTENTIAL FOR FROST ON THU NGT AND THEN ON POPS ACCOMPANYING THE PASSAGE OF ANOTHER DISTURBANCE THRU THE LOWER LKS ON FRI INTO SAT. SINCE AN UPR TROF WL DOMINATE ERN NAMERICA THRU NEXT WEEK... EXPECT BLO NORMAL TEMPS TO PREVAIL DURING THE EXTENDED PERIOD. THU...AS DEPARTING LO PRES OVER FAR SW QUEBEC AT 12Z THU SHIFTS TO THE ENE...STEADY N LLVL FLOW IS PROGGED TO WEAKEN AND BECOME MORE ACYC UNDER GENERAL DEEP LYR QVECTOR DVGC LEFT IN THE WAKE OF THE EXITING SHRTWV AND RDG AXIS EXPANDING TO THE E OF SFC HI CENTER IN THE NRN PLAINS. EXPECT PLENTY OF CLDS IN THE MRNG WITH SHOWERS MAINLY NEAR LK SUP ASSOCIATED WITH CHILLY LINGERING CYC FLOW OVER THE RELATIVELY WARM LK SUP WATERS. BUT WITH INCRSG SUBSIDENCE/ACYC FLOW IN THE PRESENCE OF DAYTIME HEATING...EXPECT THE SHOWERS TO DIMINISH AND THE CLD PATTERN TO SHIFT TO MORE INLAND SC COVERAGE UNDER THE H85 THERMAL TROF AND SUBSIDENCE INVRN SINKING TOWARD H85-9. H85 TEMPS IN THE ZERO TO -2C RANGE WL SUPPORT WELL BLO NORMAL HI TEMPS MAINLY IN THE UPR 40S/50S...COOLEST OVER THE HIER TERRAIN OF THE NW HALF. THU NGT...UNDER BLDG HI PRES WITH LOSS OF DAYTIME HEATING...EXPECT LINGERING SC TO DSPT IN THE EVNG AND GIVE WAY TO AT LEAST A PERIOD OF MOCLR SKIES AND LGT WINDS. WITH PWAT UNDER 0.5 INCH...TEMPS SHOULD FALL OFF STEADILY. THE ONE LIMITING FACTOR WL BE HOW QUICKLY HI CLDS IN ADVANCE OF SHRTWV MOVING THRU THE NRN PLAINS WL INVADE THE UPR LKS. SUSPECT THE COLD SPOTS OVER THE INTERIOR WL SEE TEMPS FALLING AOB 32...BUT WL HOLD OFF ON ANY KIND OF FREEZE WATCH/FROST HEADLINE GIVEN ACTIVE SHORT TERM...MARGINALLY LO ENUF FCST TEMPS AND COVERAGE OF THOSE REALLY LO TEMPS UNDER SOME INCRSG HI CLDS. FRI THRU SAT...ALTHOUGH THERE IS GOOD MODEL AGREEMENT ON THE TIMING AND TRACK OF A FAIRLY VIGOROUS SHRTWV THAT IS FCST TO MOVE E FM THE NRN ROCKIES ON THU AFTN THRU THE NCENTRAL PLAINS AND ACROSS THE LOWER LKS FRI NGT/SAT...THERE ARE SOME FAIRLY LARGE DIFFERENCES IN THE MSLP FIELDS AND QPF. THE 09/12Z ECWMF CONTINUES TO BE THE MODEL THAT SHOWS THE MORE IMPRESSIVE PRES FALL. WITH A DEEPER SFC REFLECTION...THE ECMWF ALSO SHOWS MORE EXPANSIVE MID LVL MSTR/PCPN EXTENDING INTO ALL OF UPR MI DURING FRI NGT/SAT MRNG. GIVEN THE POSITIVE TILT TO THE SHRTWV....EXPANSIVE HI PRES THAT IS FCST TO EXTEND FM THE NRN PLAINS INTO THE UPR LKS IN ADVANCE OF THIS SHRTWV AND DRY/STABLE NATURE OF THE ANTECEDENT AIRMASS /PWAT AOB 0.5 INCH WITH STRONG SUBSIDENCE INVRN BTWN H8-7/...SUSPECT THE NON-ECMWF MODELS SHOWING LESS SFC RESPONSE ARE ON THE RIGHT TRACK. HAVE THUS CHOSEN TO MAINTAIN ONLY LO CHC POPS...HIEST OVER THE SRN CWA CLOSER TO THE SHRTWV TRACK/AREA OF SHARPER DEEP LYR QVECTOR CNVGC. THICKER CLDS/THESE POPS WL ARRIVE ON FRI AFTN AS THE DISTURBANCE SLIDES INTO THE UPR MS RIVER VALLEY. ONCE THE SHRTWV PUSHES TO THE E ON SAT MRNG...TRAILING SHRTWV RDG/DRIER AIRMASS WL BRING A RETURN TO DRY WX/CLRG. WITH H85 TEMPS IN THE ZERO TO -2C RANGE DURING THIS TIME...THE WX WL BE UNSEASONABLY COOL. IF SKIES CLR FAST ENUF LATE FRI NGT...NOT OUT OF THE QUESTION THERE COULD BE SOME FROST OVER THE INTERIOR W ARND SUNRISE ON SAT. EXTENDED...AFTER A DRY PERIOD ASSOCIATED WITH SFC HI PRES PASSING THRU THE LOWER LKS ON SAT NGT...ANOTHER CNDN SHRTWV DIGGING THRU THE MEAN UPR TROF CENTERED OVER HUDSON BAY AND INTO THE NCENTRAL CONUS WL BRING A CHC OF MORE SHOWERS FOR SUN THRU MON. THIS DISTURBANCE WL BE MSTR DEPRIVED...SO NO HEAVY RA IS LIKELY. HI PRES MOVING E UNDER THE RISING HGTS IN THE WAKE OF THIS DISTURBANCE SHOULD BRING A RETURN OF DRY WX FOR TUE. WITH THE MEAN TROF IN PLACE...TEMPS ACRS UPR MI WL AVG BLO NORMAL DURING THIS TIME. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1148 PM EDT TUE SEP 9 2014 NNE WIND SHIFT BEHIND A COLD FRONT MOVED BROUGHT LIFR CLOUDS INTO IWD/CMX LAST EVENING. A FEW SHRA/TSRA HAVE ALSO POPPED UP ALONG FRONTAL BOUNDARY MAINLY AT IWD. AS A STRONGER DISTURBANCE MOVES NEWD AND THE MOIST LYR DEEPENS...WIDESPREAD RAIN WILL DEVELOP FROM SW TO NE AND KEEPING CONDITIONS LIFR AT IWD/CMX INTO MUCH OF WED. SINCE THE FROPA WL OCCUR LATER AT SAW...THE TRANSITION TO MVFR WILL NOT OCCUR UNTIL AROUND 08Z. BY LATE TONIGHT INTO WED MORNING LIFR CONDITIONS WILL PREVAIL AT SAW AS WELL WITH MODERATE TO OCNLY HEAVY RAIN AND GUSTY NE-N WINDS DEVELOPING BY LATE MORNING/AFTERNOON. NE-N WIND WILL GUST OVER 30 KT AT KCMX AND POSSIBLY AOA 25 KTS AT KSAW AND IWD BY LATE MORNING/MIDDAY WED. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 359 AM EDT WED SEP 10 2014 AS A DEEP LO PRES MOVES NE THRU THE UPPER MIDWEST AND ACROSS NORTHERN LOWER MI THIS EVENING ON ITS WAY INTO SE CANADA TONIGHT...THE NE GALES AFFECTING WESTERN LAKE SUPERIOR WILL SPREAD E OVER THE REST OF THE LAKE. EXPECT NNE GALES AS HI AS 40-45 KTS TODAY INTO TONIGHT BEFORE THE LO PRES SHIFTS FAR ENOUGH TO THE E AND THE GALES DIMINISH W TO E TONIGHT. AS HI PRES BUILDS TOWARD LAKE SUPERIOR FROM THE PLAINS ON THU...LINGERING N WINDS UP TO 25-30 KTS IN THE MORNING WILL DIMINISH W-E TO UNDER 15-20 KTS BY THE EVENING. RELATIVELY LIGHT WINDS UNDER 20 KTS WILL THEN DOMINATE THRU THE WEEKEND UNDER A RELATIVELY WEAK PRES GRADIENT. && .HYDROLOGY... ISSUED AT 426 AM EDT WED SEP 10 2014 RAINFALL OVER THE W THIRD OF UPPER MI HAS BEEN CONVECTIVELY ENHANCED...WITH RAINFALL RATES BRIEFLY RISING TO NEAR 6IN PER HOUR. WITH THE QUICK MOVEMENT TO THE N JUST OVER 20KTS THAT AMOUNT WAS NOT REALIZED. RADAR ESTIMATES THROUGH 08Z HAVE THE HIGHEST AMOUNTS OVER NW GOGEBIC AND ALONG THE E ONTONAGON/W HOUGHTON COUNTIES...WITH 1.5 TO 2.25IN. SOME LOCAL RIVERS CONTINUE TO RESPOND TO THE RAINFALL A FEW DAYS AGO...AND ARE RISING AT AN INCREASED RATE DO TO THE CURRENT RAIN. SPECIFICALLY THIS INCLUDES THE SOUTH BRANCH OF THE ONTONAGON RIVER AT EWEN /WHICH GIVEN THE TREND WILL SEE A SLOW RISE FOR THE NEXT SEVERAL DAYS/. THE MIDDLE BRANCH OF THE ONTONAGON RIVER AT PAULDING IS ALSO SLOWLY ON THE RISE. OTHERWISE AN AVERAGED 0.5IN HAS FALLEN W OF A LINE FROM IRON RIVER TO BARAGA. LITTLE RAIN HAS FALLEN E OF THIS LINE...WHICH WILL CHANGE OVER THE NEXT COUPLE OF HRS AS ADDITIONAL SHOWERS NEAR FROM WI. THUNDERSTORMS ARE MINIMAL OVER WI...AND PRECIP IS SLOWER THAN ORIGINALLY ANTICIPATED. HAVE BACKED OFF ON THE STORM TOTAL PRECIP OVER THE E THIRD OF THE FCST AREA AS A RESULT. EXPECT THE TRADITIONAL URBAN/SMALL STREAM FLOODING TO BE A SIGNIFICANT POSSIBILITY IN THE TYPICAL POOR DRAINAGE AREAS OF ESC IF A PERIOD OF HEAVIER DOWNPOURS DEVELOP WITH RAINFALL RATES CLOSE TO AN 0.5-1.0 INCH PER HOUR. N CNTRL UPPER MI WILL STILL LIKELY SEE SOME UPSLOPE LAKE ENHANCEMENT TODAY-TONIGHT. THE FLOOD WATCH REMAINS POSTED FOR MUCH OF W AND CENTRAL UPPER MI FOR TODAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... FLOOD WATCH THROUGH THIS EVENING FOR MIZ001>006-009>013-084. LAKE SUPERIOR... GALE WARNING FROM 8 PM THIS EVENING TO 8 AM EDT THURSDAY FOR LSZ251-267. GALE WARNING FROM 2 PM THIS AFTERNOON TO 5 AM EDT THURSDAY FOR LSZ246>250-265-266. GALE WARNING UNTIL 4 AM EDT THURSDAY FOR LSZ243>245-264. GALE WARNING UNTIL 2 AM EDT /1 AM CDT/ THURSDAY FOR LSZ240>242- 263. GALE WARNING UNTIL 11 PM EDT /10 PM CDT/ THIS EVENING FOR LSZ162. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KF LONG TERM...KC AVIATION...VOSS MARINE...KC HYDROLOGY...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
426 AM EDT WED SEP 10 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 344 PM EDT TUE SEP 9 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A SPLIT FLOW PATTERN WITH A DEVELOPING MID/UPPER LEVEL TROUGH OVER THE WRN CONUS. THE TAIL OF AN ELONGATED SHORTWAVE TROUGH MOVING THROUGH NRN ONTARIO WAS DRAGGING A COLD FRONT SLOWLY SOUTH INTO WRN LAKE SUPERIOR. A VIGOROUS SRN STREAM SHRTWV MOVING IN THE CNTRL PLAINS WILL SUPPORT DEVELOPMENT OF A SFC LOW THAT WILL MOVE INTO THE WRN LAKES WED. EVEN WITH LAKE BREEZE ONSHORE WINDS INTO WRN UPPER MI...LOW LEVEL CONV HAS NOT BEEN STRONG ENOUGH TO OVERCOME CAPPING WITH 800-750 MB TEMPS NEAR 12C...PER RUC. OTHERWISE...ABUNDANT CU PREVAILED ACROSS THE WEST HALF OF UPPER MI WHILE MORE STABLE AIR OFF OF LAKE MI HAS KEPT SKIES MOSTLY CLEAR OVER THE EAST. THE POTENTIAL REMAINS FOR SOME SHRA/TSRA THIS EVENING AS THE FRONTAL BOUNDARY MOVES THROUGH WRN UPPER MI. HOWEVER...COVERAGE SHOULD LIMITED WITH ONLY LOWER END CHANCE POPS GIVEN THE STRENGTH OF THE CAPPING. AS THE PLAINS SHRTWV MOVES TOWARD THE AREA AND THE SFC LOW DEEPENS...300-310 ISENTROPIC ASCENT ALONG WITH 800-600 MB FGEN WILL STRENGTHEN AND SUPPORT AN EXPANDING AREA OF MODERATE TO HEAVY RAIN FROM NW/N WI INTO WRN UPPER MI BY LATE EVENING AND INTO CNTRL UPPER MI LATE TONIGHT. STRONG MID/UPPER LEVEL DYNAMICS WITH A COUPLED UPPER LEVEL JET STRUCTURE AND STRONG QVECTOR CONV WILL SUPPORT A LARGE AREA OF RAIN ACROSS THE CWA WED. SOME MODEL UNCERTAINTY REMAINS AS THE NAM REMAINS MUCH DEEPER AND FARTHER TO THE NW THAN MODELS CONSENSUS AND THE GFS FASTER AND ALONG THE SOUTHERN ENVELOPE OF MODEL SPREAD. FAVORED THE MORE CONSISTENT ECMWF AND REGIONAL GEM WITH THE LOW PATH TO NEAR GRB BY 18Z AND THE STRAITS BY 00Z/THU. VERY STRONG 850 MB MOISTURE INFLOW...UPPER LEVEL AND 800-600 MB FGEN EVEN WITHOUT TSRA WILL BRING THE POTENTIAL FOR A PERIOD OF HEAVY RAIN...ESPECIALLY BTWN 09Z-18Z. UNCERTAINTY REMAINS ON THE IMPACT OF UPSTREAM CONVECTION OVER IA INTO SRN WI ON THE EVOLUTION OF THE 850-700 MB FRONTAL BOUNDARY AND MOISTURE INFLOW TO THE NORTH. HOWEVER...THE POTENTIAL REMAINS FOR QPF IN THE 1.5 INCH TO 2.0 INCH RANGE...WITH LOCALLY HIGHER AMOUNTS AOA 3 INCHES. SO THE FLOOD WATCH WILL REMAINS IN EFFECT. NE WINDS VEERING TO THE NNE WILL ALSO INCREASE WITH GUSTS LIKELY IN INTO THE 40-50 KNOT RANGE BY TO LATE AFTERNOON OVER THE KEWEENAW...ESPECIALLY FOR LOCATIONS FAVORED BY NNE FLOW SUCH AS COPPER HARBOR. AN ADVISORY WILL LIKELY BE NEEDED. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 359 AM EDT WED SEP 10 2014 MAIN FCST CONCERNS IN THE LONG TERM FOCUS ON HOW QUICKLY ON THU CLDS AND SHOWERS ASSOCIATED WITH THE WED LO PRES WL EXIT THE CWA...TEMPS AND THE POTENTIAL FOR FROST ON THU NGT AND THEN ON POPS ACCOMPANYING THE PASSAGE OF ANOTHER DISTURBANCE THRU THE LOWER LKS ON FRI INTO SAT. SINCE AN UPR TROF WL DOMINATE ERN NAMERICA THRU NEXT WEEK... EXPECT BLO NORMAL TEMPS TO PREVAIL DURING THE EXTENDED PERIOD. THU...AS DEPARTING LO PRES OVER FAR SW QUEBEC AT 12Z THU SHIFTS TO THE ENE...STEADY N LLVL FLOW IS PROGGED TO WEAKEN AND BECOME MORE ACYC UNDER GENERAL DEEP LYR QVECTOR DVGC LEFT IN THE WAKE OF THE EXITING SHRTWV AND RDG AXIS EXPANDING TO THE E OF SFC HI CENTER IN THE NRN PLAINS. EXPECT PLENTY OF CLDS IN THE MRNG WITH SHOWERS MAINLY NEAR LK SUP ASSOCIATED WITH CHILLY LINGERING CYC FLOW OVER THE RELATIVELY WARM LK SUP WATERS. BUT WITH INCRSG SUBSIDENCE/ACYC FLOW IN THE PRESENCE OF DAYTIME HEATING...EXPECT THE SHOWERS TO DIMINISH AND THE CLD PATTERN TO SHIFT TO MORE INLAND SC COVERAGE UNDER THE H85 THERMAL TROF AND SUBSIDENCE INVRN SINKING TOWARD H85-9. H85 TEMPS IN THE ZERO TO -2C RANGE WL SUPPORT WELL BLO NORMAL HI TEMPS MAINLY IN THE UPR 40S/50S...COOLEST OVER THE HIER TERRAIN OF THE NW HALF. THU NGT...UNDER BLDG HI PRES WITH LOSS OF DAYTIME HEATING...EXPECT LINGERING SC TO DSPT IN THE EVNG AND GIVE WAY TO AT LEAST A PERIOD OF MOCLR SKIES AND LGT WINDS. WITH PWAT UNDER 0.5 INCH...TEMPS SHOULD FALL OFF STEADILY. THE ONE LIMITING FACTOR WL BE HOW QUICKLY HI CLDS IN ADVANCE OF SHRTWV MOVING THRU THE NRN PLAINS WL INVADE THE UPR LKS. SUSPECT THE COLD SPOTS OVER THE INTERIOR WL SEE TEMPS FALLING AOB 32...BUT WL HOLD OFF ON ANY KIND OF FREEZE WATCH/FROST HEADLINE GIVEN ACTIVE SHORT TERM...MARGINALLY LO ENUF FCST TEMPS AND COVERAGE OF THOSE REALLY LO TEMPS UNDER SOME INCRSG HI CLDS. FRI THRU SAT...ALTHOUGH THERE IS GOOD MODEL AGREEMENT ON THE TIMING AND TRACK OF A FAIRLY VIGOROUS SHRTWV THAT IS FCST TO MOVE E FM THE NRN ROCKIES ON THU AFTN THRU THE NCENTRAL PLAINS AND ACROSS THE LOWER LKS FRI NGT/SAT...THERE ARE SOME FAIRLY LARGE DIFFERENCES IN THE MSLP FIELDS AND QPF. THE 09/12Z ECWMF CONTINUES TO BE THE MODEL THAT SHOWS THE MORE IMPRESSIVE PRES FALL. WITH A DEEPER SFC REFLECTION...THE ECMWF ALSO SHOWS MORE EXPANSIVE MID LVL MSTR/PCPN EXTENDING INTO ALL OF UPR MI DURING FRI NGT/SAT MRNG. GIVEN THE POSITIVE TILT TO THE SHRTWV....EXPANSIVE HI PRES THAT IS FCST TO EXTEND FM THE NRN PLAINS INTO THE UPR LKS IN ADVANCE OF THIS SHRTWV AND DRY/STABLE NATURE OF THE ANTECEDENT AIRMASS /PWAT AOB 0.5 INCH WITH STRONG SUBSIDENCE INVRN BTWN H8-7/...SUSPECT THE NON-ECMWF MODELS SHOWING LESS SFC RESPONSE ARE ON THE RIGHT TRACK. HAVE THUS CHOSEN TO MAINTAIN ONLY LO CHC POPS...HIEST OVER THE SRN CWA CLOSER TO THE SHRTWV TRACK/AREA OF SHARPER DEEP LYR QVECTOR CNVGC. THICKER CLDS/THESE POPS WL ARRIVE ON FRI AFTN AS THE DISTURBANCE SLIDES INTO THE UPR MS RIVER VALLEY. ONCE THE SHRTWV PUSHES TO THE E ON SAT MRNG...TRAILING SHRTWV RDG/DRIER AIRMASS WL BRING A RETURN TO DRY WX/CLRG. WITH H85 TEMPS IN THE ZERO TO -2C RANGE DURING THIS TIME...THE WX WL BE UNSEASONABLY COOL. IF SKIES CLR FAST ENUF LATE FRI NGT...NOT OUT OF THE QUESTION THERE COULD BE SOME FROST OVER THE INTERIOR W ARND SUNRISE ON SAT. EXTENDED...AFTER A DRY PERIOD ASSOCIATED WITH SFC HI PRES PASSING THRU THE LOWER LKS ON SAT NGT...ANOTHER CNDN SHRTWV DIGGING THRU THE MEAN UPR TROF CENTERED OVER HUDSON BAY AND INTO THE NCENTRAL CONUS WL BRING A CHC OF MORE SHOWERS FOR SUN THRU MON. THIS DISTURBANCE WL BE MSTR DEPRIVED...SO NO HEAVY RA IS LIKELY. HI PRES MOVING E UNDER THE RISING HGTS IN THE WAKE OF THIS DISTURBANCE SHOULD BRING A RETURN OF DRY WX FOR TUE. WITH THE MEAN TROF IN PLACE...TEMPS ACRS UPR MI WL AVG BLO NORMAL DURING THIS TIME. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1148 PM EDT TUE SEP 9 2014 NNE WIND SHIFT BEHIND A COLD FRONT MOVED BROUGHT LIFR CLOUDS INTO IWD/CMX LAST EVENING. A FEW SHRA/TSRA HAVE ALSO POPPED UP ALONG FRONTAL BOUNDARY MAINLY AT IWD. AS A STRONGER DISTURBANCE MOVES NEWD AND THE MOIST LYR DEEPENS...WIDESPREAD RAIN WILL DEVELOP FROM SW TO NE AND KEEPING CONDITIONS LIFR AT IWD/CMX INTO MUCH OF WED. SINCE THE FROPA WL OCCUR LATER AT SAW...THE TRANSITION TO MVFR WILL NOT OCCUR UNTIL AROUND 08Z. BY LATE TONIGHT INTO WED MORNING LIFR CONDITIONS WILL PREVAIL AT SAW AS WELL WITH MODERATE TO OCNLY HEAVY RAIN AND GUSTY NE-N WINDS DEVELOPING BY LATE MORNING/AFTERNOON. NE-N WIND WILL GUST OVER 30 KT AT KCMX AND POSSIBLY AOA 25 KTS AT KSAW AND IWD BY LATE MORNING/MIDDAY WED. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 359 AM EDT WED SEP 10 2014 AS A DEEP LO PRES MOVES NE THRU THE UPPER MIDWEST AND ACROSS NORTHERN LOWER MI THIS EVENING ON ITS WAY INTO SE CANADA TONIGHT...THE NE GALES AFFECTING WESTERN LAKE SUPERIOR WILL SPREAD E OVER THE REST OF THE LAKE. EXPECT NNE GALES AS HI AS 40-45 KTS TODAY INTO TONIGHT BEFORE THE LO PRES SHIFTS FAR ENOUGH TO THE E AND THE GALES DIMINISH W TO E TONIGHT. AS HI PRES BUILDS TOWARD LAKE SUPERIOR FROM THE PLAINS ON THU...LINGERING N WINDS UP TO 25-30 KTS IN THE MORNING WILL DIMINISH W-E TO UNDER 15-20 KTS BY THE EVENING. RELATIVELY LIGHT WINDS UNDER 20 KTS WILL THEN DOMINATE THRU THE WEEKEND UNDER A RELATIVELY WEAK PRES GRADIENT. && .HYDROLOGY... ISSUED AT 426 AM EDT WED SEP 10 2014 RAINFALL OVER THE W THIRD OF UPPER MI HAS BEEN CONVECTIVELY ENHANCED...WITH RAINFALL RATES BRIEFLY RISING TO NEAR 6IN PER HOUR. WITH THE QUICK MOVEMENT TO THE N JUST OVER 20KTS THAT AMOUNT WAS NOT REALIZED. RADAR ESTIMATES THROUGH 08Z HAVE THE HIGHEST AMOUNTS OVER NW GOGEBIC AND ALONG THE E ONTONAGON/W HOUGHTON COUNTIES...WITH 1.5 TO 2.25IN. SOME LOCAL RIVERS CONTINUE TO RESPOND TO THE RAINFALL A FEW DAYS AGO...AND ARE RISING AT AN INCREASED RATE DO TO THE CURRENT RAIN. SPECIFICALLY THIS INCLUDES THE SOUTH BRANCH OF THE ONTONAGON RIVER AT EWEN /WHICH GIVEN THE TREND WILL SEE A SLOW RISE FOR THE NEXT SEVERAL DAYS/. THE MIDDLE BRANCH OF THE ONTONAGON RIVER AT PAULDING IS ALSO SLOWLY ON THE RISE. OTHERWISE AN AVERAGED 0.5IN HAS FALLEN W OF A LINE FROM IRON RIVER TO BARAGA. LITTLE RAIN HAS FALLEN E OF THIS LINE...WHICH WILL CHANGE OVER THE NEXT COUPLE OF HRS AS ADDITIONAL SHOWERS NEAR FROM WI. THUNDERSTORMS ARE MINIMAL OVER WI...AND PRECIP IS SLOWER THAN ORIGINALLY ANTICIPATED. HAVE BACKED OFF ON THE STORM TOTAL PRECIP OVER THE E THIRD OF THE FCST AREA AS A RESULT. EXPECT THE TRADITIONAL URBAN/SMALL STREAM FLOODING TO BE A SIGNIFICANT POSSIBILITY IN THE TYPICAL POOR DRAINAGE AREAS OF ESC IF A PERIOD OF HEAVIER DOWNPOURS DEVELOP WITH RAINFALL RATES CLOSE TO AN 0.5-1.0 INCH PER HOUR. N CNTRL UPPER MI WILL STILL LIKELY SEE SOME UPSLOPE LAKE ENHANCEMENT TODAY-TONIGHT. THE FLOOD WATCH REMAINS POSTED FOR MUCH OF W AND CENTRAL UPPER MI FOR TODAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... FLOOD WATCH THROUGH THIS EVENING FOR MIZ001>006-009>013-084. LAKE SUPERIOR... GALE WARNING FROM 8 PM THIS EVENING TO 8 AM EDT THURSDAY FOR LSZ251-267. GALE WARNING FROM 2 PM THIS AFTERNOON TO 5 AM EDT THURSDAY FOR LSZ246>250-265-266. GALE WARNING UNTIL 4 AM EDT THURSDAY FOR LSZ243>245-264. GALE WARNING UNTIL 2 AM EDT /1 AM CDT/ THURSDAY FOR LSZ240>242- 263. GALE WARNING UNTIL 11 PM EDT /10 PM CDT/ THIS EVENING FOR LSZ162. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KC AVIATION...VOSS MARINE...KC HYDROLOGY...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
405 AM EDT WED SEP 10 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 344 PM EDT TUE SEP 9 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A SPLIT FLOW PATTERN WITH A DEVELOPING MID/UPPER LEVEL TROUGH OVER THE WRN CONUS. THE TAIL OF AN ELONGATED SHORTWAVE TROUGH MOVING THROUGH NRN ONTARIO WAS DRAGGING A COLD FRONT SLOWLY SOUTH INTO WRN LAKE SUPERIOR. A VIGOROUS SRN STREAM SHRTWV MOVING IN THE CNTRL PLAINS WILL SUPPORT DEVELOPMENT OF A SFC LOW THAT WILL MOVE INTO THE WRN LAKES WED. EVEN WITH LAKE BREEZE ONSHORE WINDS INTO WRN UPPER MI...LOW LEVEL CONV HAS NOT BEEN STRONG ENOUGH TO OVERCOME CAPPING WITH 800-750 MB TEMPS NEAR 12C...PER RUC. OTHERWISE...ABUNDANT CU PREVAILED ACROSS THE WEST HALF OF UPPER MI WHILE MORE STABLE AIR OFF OF LAKE MI HAS KEPT SKIES MOSTLY CLEAR OVER THE EAST. THE POTENTIAL REMAINS FOR SOME SHRA/TSRA THIS EVENING AS THE FRONTAL BOUNDARY MOVES THROUGH WRN UPPER MI. HOWEVER...COVERAGE SHOULD LIMITED WITH ONLY LOWER END CHANCE POPS GIVEN THE STRENGTH OF THE CAPPING. AS THE PLAINS SHRTWV MOVES TOWARD THE AREA AND THE SFC LOW DEEPENS...300-310 ISENTROPIC ASCENT ALONG WITH 800-600 MB FGEN WILL STRENGTHEN AND SUPPORT AN EXPANDING AREA OF MODERATE TO HEAVY RAIN FROM NW/N WI INTO WRN UPPER MI BY LATE EVENING AND INTO CNTRL UPPER MI LATE TONIGHT. STRONG MID/UPPER LEVEL DYNAMICS WITH A COUPLED UPPER LEVEL JET STRUCTURE AND STRONG QVECTOR CONV WILL SUPPORT A LARGE AREA OF RAIN ACROSS THE CWA WED. SOME MODEL UNCERTAINTY REMAINS AS THE NAM REMAINS MUCH DEEPER AND FARTHER TO THE NW THAN MODELS CONSENSUS AND THE GFS FASTER AND ALONG THE SOUTHERN ENVELOPE OF MODEL SPREAD. FAVORED THE MORE CONSISTENT ECMWF AND REGIONAL GEM WITH THE LOW PATH TO NEAR GRB BY 18Z AND THE STRAITS BY 00Z/THU. VERY STRONG 850 MB MOISTURE INFLOW...UPPER LEVEL AND 800-600 MB FGEN EVEN WITHOUT TSRA WILL BRING THE POTENTIAL FOR A PERIOD OF HEAVY RAIN...ESPECIALLY BTWN 09Z-18Z. UNCERTAINTY REMAINS ON THE IMPACT OF UPSTREAM CONVECTION OVER IA INTO SRN WI ON THE EVOLUTION OF THE 850-700 MB FRONTAL BOUNDARY AND MOISTURE INFLOW TO THE NORTH. HOWEVER...THE POTENTIAL REMAINS FOR QPF IN THE 1.5 INCH TO 2.0 INCH RANGE...WITH LOCALLY HIGHER AMOUNTS AOA 3 INCHES. SO THE FLOOD WATCH WILL REMAINS IN EFFECT. NE WINDS VEERING TO THE NNE WILL ALSO INCREASE WITH GUSTS LIKELY IN INTO THE 40-50 KNOT RANGE BY TO LATE AFTERNOON OVER THE KEWEENAW...ESPECIALLY FOR LOCATIONS FAVORED BY NNE FLOW SUCH AS COPPER HARBOR. AN ADVISORY WILL LIKELY BE NEEDED. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 359 AM EDT WED SEP 10 2014 MAIN FCST CONCERNS IN THE LONG TERM FOCUS ON HOW QUICKLY ON THU CLDS AND SHOWERS ASSOCIATED WITH THE WED LO PRES WL EXIT THE CWA...TEMPS AND THE POTENTIAL FOR FROST ON THU NGT AND THEN ON POPS ACCOMPANYING THE PASSAGE OF ANOTHER DISTURBANCE THRU THE LOWER LKS ON FRI INTO SAT. SINCE AN UPR TROF WL DOMINATE ERN NAMERICA THRU NEXT WEEK... EXPECT BLO NORMAL TEMPS TO PREVAIL DURING THE EXTENDED PERIOD. THU...AS DEPARTING LO PRES OVER FAR SW QUEBEC AT 12Z THU SHIFTS TO THE ENE...STEADY N LLVL FLOW IS PROGGED TO WEAKEN AND BECOME MORE ACYC UNDER GENERAL DEEP LYR QVECTOR DVGC LEFT IN THE WAKE OF THE EXITING SHRTWV AND RDG AXIS EXPANDING TO THE E OF SFC HI CENTER IN THE NRN PLAINS. EXPECT PLENTY OF CLDS IN THE MRNG WITH SHOWERS MAINLY NEAR LK SUP ASSOCIATED WITH CHILLY LINGERING CYC FLOW OVER THE RELATIVELY WARM LK SUP WATERS. BUT WITH INCRSG SUBSIDENCE/ACYC FLOW IN THE PRESENCE OF DAYTIME HEATING...EXPECT THE SHOWERS TO DIMINISH AND THE CLD PATTERN TO SHIFT TO MORE INLAND SC COVERAGE UNDER THE H85 THERMAL TROF AND SUBSIDENCE INVRN SINKING TOWARD H85-9. H85 TEMPS IN THE ZERO TO -2C RANGE WL SUPPORT WELL BLO NORMAL HI TEMPS MAINLY IN THE UPR 40S/50S...COOLEST OVER THE HIER TERRAIN OF THE NW HALF. THU NGT...UNDER BLDG HI PRES WITH LOSS OF DAYTIME HEATING...EXPECT LINGERING SC TO DSPT IN THE EVNG AND GIVE WAY TO AT LEAST A PERIOD OF MOCLR SKIES AND LGT WINDS. WITH PWAT UNDER 0.5 INCH...TEMPS SHOULD FALL OFF STEADILY. THE ONE LIMITING FACTOR WL BE HOW QUICKLY HI CLDS IN ADVANCE OF SHRTWV MOVING THRU THE NRN PLAINS WL INVADE THE UPR LKS. SUSPECT THE COLD SPOTS OVER THE INTERIOR WL SEE TEMPS FALLING AOB 32...BUT WL HOLD OFF ON ANY KIND OF FREEZE WATCH/FROST HEADLINE GIVEN ACTIVE SHORT TERM...MARGINALLY LO ENUF FCST TEMPS AND COVERAGE OF THOSE REALLY LO TEMPS UNDER SOME INCRSG HI CLDS. FRI THRU SAT...ALTHOUGH THERE IS GOOD MODEL AGREEMENT ON THE TIMING AND TRACK OF A FAIRLY VIGOROUS SHRTWV THAT IS FCST TO MOVE E FM THE NRN ROCKIES ON THU AFTN THRU THE NCENTRAL PLAINS AND ACROSS THE LOWER LKS FRI NGT/SAT...THERE ARE SOME FAIRLY LARGE DIFFERENCES IN THE MSLP FIELDS AND QPF. THE 09/12Z ECWMF CONTINUES TO BE THE MODEL THAT SHOWS THE MORE IMPRESSIVE PRES FALL. WITH A DEEPER SFC REFLECTION...THE ECMWF ALSO SHOWS MORE EXPANSIVE MID LVL MSTR/PCPN EXTENDING INTO ALL OF UPR MI DURING FRI NGT/SAT MRNG. GIVEN THE POSITIVE TILT TO THE SHRTWV....EXPANSIVE HI PRES THAT IS FCST TO EXTEND FM THE NRN PLAINS INTO THE UPR LKS IN ADVANCE OF THIS SHRTWV AND DRY/STABLE NATURE OF THE ANTECEDENT AIRMASS /PWAT AOB 0.5 INCH WITH STRONG SUBSIDENCE INVRN BTWN H8-7/...SUSPECT THE NON-ECMWF MODELS SHOWING LESS SFC RESPONSE ARE ON THE RIGHT TRACK. HAVE THUS CHOSEN TO MAINTAIN ONLY LO CHC POPS...HIEST OVER THE SRN CWA CLOSER TO THE SHRTWV TRACK/AREA OF SHARPER DEEP LYR QVECTOR CNVGC. THICKER CLDS/THESE POPS WL ARRIVE ON FRI AFTN AS THE DISTURBANCE SLIDES INTO THE UPR MS RIVER VALLEY. ONCE THE SHRTWV PUSHES TO THE E ON SAT MRNG...TRAILING SHRTWV RDG/DRIER AIRMASS WL BRING A RETURN TO DRY WX/CLRG. WITH H85 TEMPS IN THE ZERO TO -2C RANGE DURING THIS TIME...THE WX WL BE UNSEASONABLY COOL. IF SKIES CLR FAST ENUF LATE FRI NGT...NOT OUT OF THE QUESTION THERE COULD BE SOME FROST OVER THE INTERIOR W ARND SUNRISE ON SAT. EXTENDED...AFTER A DRY PERIOD ASSOCIATED WITH SFC HI PRES PASSING THRU THE LOWER LKS ON SAT NGT...ANOTHER CNDN SHRTWV DIGGING THRU THE MEAN UPR TROF CENTERED OVER HUDSON BAY AND INTO THE NCENTRAL CONUS WL BRING A CHC OF MORE SHOWERS FOR SUN THRU MON. THIS DISTURBANCE WL BE MSTR DEPRIVED...SO NO HEAVY RA IS LIKELY. HI PRES MOVING E UNDER THE RISING HGTS IN THE WAKE OF THIS DISTURBANCE SHOULD BRING A RETURN OF DRY WX FOR TUE. WITH THE MEAN TROF IN PLACE...TEMPS ACRS UPR MI WL AVG BLO NORMAL DURING THIS TIME. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1148 PM EDT TUE SEP 9 2014 NNE WIND SHIFT BEHIND A COLD FRONT MOVED BROUGHT LIFR CLOUDS INTO IWD/CMX LAST EVENING. A FEW SHRA/TSRA HAVE ALSO POPPED UP ALONG FRONTAL BOUNDARY MAINLY AT IWD. AS A STRONGER DISTURBANCE MOVES NEWD AND THE MOIST LYR DEEPENS...WIDESPREAD RAIN WILL DEVELOP FROM SW TO NE AND KEEPING CONDITIONS LIFR AT IWD/CMX INTO MUCH OF WED. SINCE THE FROPA WL OCCUR LATER AT SAW...THE TRANSITION TO MVFR WILL NOT OCCUR UNTIL AROUND 08Z. BY LATE TONIGHT INTO WED MORNING LIFR CONDITIONS WILL PREVAIL AT SAW AS WELL WITH MODERATE TO OCNLY HEAVY RAIN AND GUSTY NE-N WINDS DEVELOPING BY LATE MORNING/AFTERNOON. NE-N WIND WILL GUST OVER 30 KT AT KCMX AND POSSIBLY AOA 25 KTS AT KSAW AND IWD BY LATE MORNING/MIDDAY WED. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 359 AM EDT WED SEP 10 2014AS A DEEP LO PRES MOVES NE THRU THE UPPER MIDWEST AND ACROSS NORTHERN LOWER MI THIS EVENING ON ITS WAY INTO SE CANADA TONIGHT...THE NE GALES AFFECTING WESTERN LAKE SUPERIOR WILL SPREAD E OVER THE REST OF THE LAKE. EXPECT NNE GALES AS HI AS 40-45 KTS TODAY INTO TONIGHT BEFORE THE LO PRES SHIFTS FAR ENOUGH TO THE E AND THE GALES DIMINISH W TO E TONIGHT. AS HI PRES BUILDS TOWARD LAKE SUPERIOR FROM THE PLAINS ON THU...LINGERING N WINDS UP TO 25-30 KTS IN THE MORNING WILL DIMINISH W-E TO UNDER 15-20 KTS BY THE EVENING. RELATIVELY LIGHT WINDS UNDER 20 KTS WILL THEN DOMINATE THRU THE WEEKEND UNDER A RELATIVELY WEAK PRES GRADIENT. && .HYDROLOGY... ISSUED AT 344 PM EDT TUE SEP 9 2014 RAINFALL TOTALS FROM TONIGHT THROUGH WEDNESDAY NIGHT ACROSS UPPER MI RANGE FROM JUST OVER 1.5 TO LOCALLY 3 INCHES. UNCERTAINTY REMAINS WHERE THE HEAVIER BANDS OF RAIN WILL DEVELOP. HIGHER TOTALS INTO WED NIGHT ARE EXPECTED FOR LOCATIONS IN N CNTRL UPPER MI WHERE STRONG UPSLOPE FLOW WILL BOOST RAINFALL AMOUNTS. THE FLOOD WATCH REMAINS POSTED FOR MUCH OF W AND CENTRAL UPPER MI. EXPECT THE TRADITIONAL URBAN/SMALL STREAM FLOODING TO BE A SIGNIFICANT POSSIBILITY IN THE TYPICAL POOR DRAINAGE AREAS OF ESC IF A PERIOD OF HEAVIER DOWNPOURS DEVELOP WITH RAINFALL RATES CLOSE TO AN 0.5-1.0 INCH PER HOUR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... FLOOD WATCH THROUGH THIS EVENING FOR MIZ001>006-009>013-084. LAKE SUPERIOR... GALE WARNING FROM 8 PM THIS EVENING TO 8 AM EDT THURSDAY FOR LSZ251-267. GALE WARNING FROM 2 PM THIS AFTERNOON TO 5 AM EDT THURSDAY FOR LSZ246>250-265-266. GALE WARNING UNTIL 4 AM EDT THURSDAY FOR LSZ243>245-264. GALE WARNING UNTIL 2 AM EDT /1 AM CDT/ THURSDAY FOR LSZ240>242- 263. GALE WARNING UNTIL 11 PM EDT /10 PM CDT/ THIS EVENING FOR LSZ162. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KC AVIATION...VOSS MARINE...KC HYDROLOGY...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
326 AM CDT WED SEP 10 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 327 AM CDT WED SEP 10 2014 MODERATE TO HEAVY RAIN CONTINUES OVER MUCH OF EAST CENTRAL MN AND WEST CENTRAL WISCONSIN. ALTHOUGH THE GREATER MOISTURE TRANSPORT HAS EXITED TO THE SOUTHEAST OF THE AREA...FAIRLY STRONG MID LEVEL FRONTOGENESIS REMAINS OVER TWO SPECIFIC AREAS OF THE CWA. ONE OVER EAST CENTRAL MN AND NORTHWEST WISCONSIN AND THE OTHER DEVELOPING TO THE SOUTHEAST...MOVING NOW INTO WEST CENTRAL WISCONSIN. THE RUC AND NAM SHOW THIS GRADUALLY WEAKENING AND LIFTING OFF TO THE EAST DURING THE MORNING. THIS SHOULD TAKE THE RAIN WITH IT. THE THREAT OF PONDING WATER REMAINS MAINLY ACROSS WEST CENTRAL WISCONSIN INTO THE MORNING. COLLABORATION WITH SURROUNDING OFFICES DID YIELD THE CONTINUATION OF THE FLOOD WATCH INTO WEST CENTRAL WISCONSIN. TODAYS HIGH TEMPERATURES WILL LIKELY OCCUR THIS MORNING AS WELL. THEY MAY CONTINUE TO DROP OFF THROUGH MID MORNING OR SO BEFORE LEVELING OFF INTO THE AFTERNOON. STRONG NORTH WINDS RE EXPECTED TO DEVELOP EAST AS LOW LEVEL CAA SPREADS OVER THE REGION. CLOUDS ARE EXPECTED TO HANG TOUGH OVER MUCH OF THE AREA INTO THE NIGHT. THERE IS SOME INDICATION THAT IN THE WAKE OF THE TROUGH...SUBSIDENCE COULD BE STRONG ENOUGH TO ERODE THE LOWER CLOUD COVER. WINDS WILL SLOWLY DIMINISH AS THE LOW CONTINUE TO LIFT EAST/NORTHEAST INTO THE NIGHT. IT SHOULD COOL RAPIDLY IF BREAKS DO DEVELOP INTO THE NORTH CENTRAL CWA DURING THE NIGHT. SOME UPPER 30S POSSIBLE WHERE THIS OCCURS. READINGS IN THE LOWER 40S SHOULD REMAIN ELSEWHERE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 327 AM CDT WED SEP 10 2014 THE LONG TERM FORECAST WILL FEATURE THE PASSAGE OF A SHORTWAVE TROUGH AT THE BEGINNING OF THE PERIOD...FOLLOWED BY BRIEF SEMI- ZONAL FLOW OVER THE WEEKEND...AND THEN A PATTERN TRANSITION TO WESTERN RIDGING AND EASTERN TROUGHING THROUGH THE FIRST HALF OF NEXT WEEK. ON THURSDAY...A BROAD SURFACE HIGH BECOMES ESTABLISHED ACROSS THE NATION/S MIDSECTION...WHILE A WEAK SHORTWAVE SLIDES EAST/SOUTHEAST ACROSS THE AREA FROM THE NORTHERN/CANADIAN ROCKIES. WHILE THE BETTER FORCING AND MORE PLENTIFUL MOISTURE WILL LIE SOUTH OF THE FORECAST AREA...COULD SEE A FEW SHOWERS SNEAK INTO SOUTHERN MN AND WEST CENTRAL WI LATE THURSDAY NIGHT AND FRIDAY. TEMPERATURES WILL BE COOL...WITH HIGHS IN THE 50S ON THURSDAY AND FRIDAY...AND LOWS DIPPING INTO THE MID TO UPPER 30S. DEPENDING ON HOW THE CLEARING GOES AND WINDS...COULD POSSIBLY SEE SOME FROST ON SATURDAY MORNING. SATURDAY LOOKS TO HAVE THE HIGHEST POTENTIAL TO BE AN ENTIRELY DRY DAY...AS SURFACE HIGH PRESSURE PREVAILS AND IN THE ABSENCE OF ANY MID/UPPER DISTURBANCES. SUNDAY BRINGS THE ARRIVAL OF WEAK SHORTWAVE ENERGY IN THE BASE OF THE MANITOBA/ONTARIO TROUGH. MOISTURE AND FORCING ARE THE MOST ROBUST NORTH AND EAST OF THE FORECAST AREA...BUT SUFFICIENT TO WARRANT 20 POPS LOCALLY. ON MONDAY...THINGS START TO DRY OUT WITH THE PATTERN EVOLUTION TO WESTERN RIDGING. OVERALL...SHOULD BE DRY WITH SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH MID-WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1037 PM CDT TUE SEP 9 2014 CONDITIONS TO CONTINUE DETERIORATING THRU THE OVERNIGHT HOURS AS A STORM SYSTEM MOVING NE FROM THE CENTRAL PLAINS INTO THE GREAT LAKES WILL SPREAD RAIN ACROSS THE ENTIRE REGION BY THE EARLY MORNING HOURS. CONDITIONS WILL LIKELY HIT IFR AT ALL TERMINALS...WITH LIFR CERTAINLY POSSIBLE...FOR BOTH CEILINGS AND VSBY. CONDITIONS WILL REMAIN DEGRADED THRU THE OVERNIGHT HOURS WITH RAINFALL GRADUALLY ENDING FROM W TO E BY LATE MORNING. CEILINGS WILL SLOWLY LIFT DURG THE DAY WED AND MAY REACH VFR LEVELS BY WED EVE. WINDS WILL REMAIN BREEZY/GUSTY OVERNIGHT AS THEY SWING FROM E-SE TO NE-N...THEN SETTLING ON N FOR MUCH OF THE DAY WED BEFORE SPEEDS DIMINISH WED EVE. HAVE KEPT TSTM MENTION AT A MINIMAL...IF AT ALL...DUE TO LOW CONFIDENCE IN PINPOINTING LOCATION/TIMING. KMSP...MVFR CONDS TO START THE 10/06Z TAFS WITH CONDS CONTINUING TO DEGRADE THRU THE EARLY MRNG HOURS. CIGS LIKELY TO HIT IFR LEVELS SHORTLY AFTER MIDNIGHT AND ARE EXPECTED TO REMAIN BELOW 1000 FT THRU LATE WED MRNG. RAIN WILL BE HEAVIEST OVERNIGHT BUT LOOKS TO BECOME LIGHT BY THE MORNING PUSH...EVENTUALLY ENDING BY MIDDAY. THAT SAID...CEILINGS LOOK TO REMAIN BELOW 1700 FT FOR MUCH IF NOT THE ENTIRE DAY WED. /OUTLOOK FOR KMSP/ WED...MVFR THEN VFR LATE. WINDS NNW AT 20G25KTS. THU...VFR. WINDS NW AT 10G15KTS. FRI...VFR. WINDS NW AT 10G15KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR WIZ015-016- 023>028. && $$ SHORT TERM...DWE LONG TERM...LS AVIATION...JPC
AREA FORECAST DISCUSSION
NWS BILLINGS MT
255 AM MDT WED SEP 10 2014 .SHORT TERM...VALID FOR TDY AND THU... MAIN FORECAST ISSUE REVOLVES AROUND POTENTIAL EARLY SEASON SNOW EVENT TONIGHT AND THURSDAY. DYNAMIC UPPER LOW DROPPING ALONG THE SPINE OF THE CANADIAN ROCKIES...WITH AN IMPRESSIVE 120KT H3 NWLY JET ANALYZED IN CENTRAL BRITISH COLUMBIA. CLOUD TOPS IN STRONGLY DIFFLUENT REGION OF THIS LOW HAVE BEEN COOLING RAPIDLY TONIGHT WITH TOPS TO -45C AT 08Z. LATEST OBS TO OUR NORTH SHOW SNOW ALONG THE EASTERN SLOPES OF THE CANADIAN ROCKIES FROM CALGARY TO EDSON. LATEST MODELS AND EVEN THE 07Z RAP SHOW THE JET NOSING TOWARD SOUTH CENTRAL MT BY THIS EVENING...LEAVING US IN A FAVORABLE POSITION FOR UPPER DIVERGENCE. ALL MODELS HAVE BEEN CONSISTENTLY SHOWING STRONG Q-VECTOR CONVERGENCE OVER OUR CWA TONIGHT THRU MUCH OF THURSDAY. ASCENT WILL NOT BE AN ISSUE WITH THIS SYSTEM...BUT AREA OF FRONTOGENESIS AND UPSLOPE FLOW WILL DICTATE WHERE THE HEAVIEST PCPN WILL BE. CONFIDENCE CONTINUES TO INCREASE FOR AN UPSLOPE EVENT MATERIALIZING BY THIS EVENING AND LASTING THROUGH MUCH OF THURSDAY. LATEST OBSERVATIONS TO OUR NORTH HELP TO GIVE CREDENCE TO THIS SCENARIO. IT ALSO SHOULD BE NOTED THAT MID LEVEL LAPSE RATES ON THE ORDER OF 6-7 C/KM OVER OUR WEST SUGGEST A CONVECTIVE COMPONENT OF THE PCPN TONIGHT THROUGH THURSDAY. PCPN CHANCES WILL BE INCREASING TODAY WITH ISENTROPIC ASCENT AND DIFFLUENCE ALOFT AND LATEST REGIONAL RADAR SHOWS SHOWERS SPREADING IN FROM THE NORTH. AREAS OF FOG/DRIZZLE ALSO EXIST PER THE LOW LEVEL SATURATED LAYER WITH UPSLOPE WINDS. TEMPS ACROSS OUR CWA WILL SUPPORT A CHILLY RAIN WITH THE EXCEPTION OF THE HIGH COUNTRY. BY 00Z...SECONDARY PUSH OF COLD ADVECTION WILL KICK IN SO EXPECT SNOW LEVELS TO FALL SIGNIFICANTLY BY THIS EVENING. HAVE ISSUED A WINTER WX ADVISORY FOR OUR NW PARTS...SPECIFICALLY FROM THE EAST SIDE OF THE CRAZY MTNS THROUGH JUDITH GAP...PER A PERIOD OF DEEP EAST FLOW AS THE UPPER TROF MOVES IN AND AN EXPECTED TRANSITION TO SNOW BY THIS EVENING. WOULD EXPECT THE BEARTOOTH AND RED LODGE FOOTHILLS TO SEE UPSLOPE SNOWFALL BEGINNING SOMETIME THIS EVENING ALSO. HAVE ISSUED A WINTER STORM WARNING FOR THE FOOTHILLS AND ALSO THE NORTH/EAST SLOPES OF THE BEARTOOTH...ABSAROKA AND CRAZY MTNS. FOR ALL OF THESE HIGHLIGHTS THE SNOW AMTS WILL VARY PER ELEVATION BUT THE BIGGEST IMPACT WILL BE THE POTENTIAL FOR DOWNED TREES AND POWER LINES. ANYONE PLANNING TRIPS TO THE HIGH COUNTRY WILL ALSO BE IMPACTED INCLUDING BEARTOOTH PASS. MODELS CONTINUE TO SUGGEST BETWEEN A HALF INCH AND INCH OF PCPN DURING TIME OF PEAK ASCENT...SO SEVERAL INCHES OF SNOWFALL COULD OCCUR IN THESE UPSLOPE AREAS. TURNING TO THE BIG HORNS AND SHERIDAN COUNTY...THOUGH THE MTNS WILL SEE A HEAVY SNOWFALL...TRANSITION TO SNOW WILL BE A BIT LATER FOR THE CITY OF SHERIDAN...PERHAPS LATE EVENING OR INTO THE OVERNIGHT HOURS. POTENTIAL STILL EXISTS FOR AN INCH OF WATER AND HEAVY SNOWFALL ON THE EASTERN ASPECTS OF THE BIG HORNS. GIVEN SOME UNCERTAINTY IN SFC TEMPS IN SHERIDAN WILL LET THE WATCH CONTINUE AND HAVE THE DAY SHIFT MAKE THE FINAL CALL ON SPECIFIC HIGHLIGHTS. OTHER LOCATIONS WHICH MAY BE IMPACTED INCLUDE THE HIGHER HILLS ACROSS OUR SOUTHEAST FROM SOUTHERN BIG HORN TO POWDER RIVER COUNTIES...SUCH PLACES AS THE WOLF MTNS AND LAME DEER DIVIDE. WOULD EXPECT SOME SLUSHY ACCUMULATION IN THESE AREAS TOO ESPECIALLY IF FRONTOGENESIS LINGERS A BIT NORTH OF THE FOOTHILLS AS SOME MODELS SUGGEST. SYSTEM WILL WIND DOWN THURSDAY AFTERNOON AND EVENING. TEMPS TODAY AND WEDNESDAY WILL MAX OUT ONLY IN THE 40S...WITH SOME RECORD COLD HIGH TEMPS BEING CHALLENGED. COLDEST NIGHT WILL BE THURSDAY NIGHT AS 1035MB SFC HIGH BUILDS IN AND ALLOWS FOR CLEARING AND STRONG RADIATIONAL COOLING. SOME RECORD LOWS ARE POSSIBLE THURSDAY NIGHT...AND SHERIDAN MAY SEE A LOW TEMP NEAR 20 DEGREES...A REMARKABLE NUMBER FOR SEPTEMBER 12TH. JKL .LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE... ONCE THE STORM SYSTEM EXITS THE AREA LATE THURSDAY...NORTHWESTERLY FLOW WILL REMAIN OVER THE AREA INTO THE WEEKEND. LATEST MODEL RUNS CONTINUE TO TREND DRIER WITH THE FORECAST FOR THE WEEKEND AS CLIPPER TYPE DISTURBANCES IN THE NORTHWEST STAY MAINLY NORTH OF THE AREA. THIS LEAVES A DRIER DOWNSLOPE REGIME IN PLACE FOR SOUTHERN MONTANA. TEMPERATURES WILL REMAIN BELOW AVERAGE THROUGH THE WEEKEND. BY EARLY NEXT WEEK FLOW ALOFT TURNS WESTERLY ALLOWING STRONGER DOWNSLOPE WARMING AND DRYING...WITH TEMPERATURES RESPONDING INTO THE 70S AND MAYBE EVEN LOWER 80S BY NEXT WEDNESDAY. WILL KEEP AN EYE ON CLIPPER SYSTEM PROGRESSION FOR ANY SIGNS OF A SOUTHWARD SHIFT THAT COULD BRING A PERIOD OF SHOWERS TO THE AREA THIS WEEKEND...BUT OVERALL LOOKS LIKE A VERY PLEASANT WEEKEND AHEAD AT THIS TIME. CHAMBERS && .AVIATION... IFR OR LOWER CONDITIONS WILL BE WIDESPREAD THIS MORNING...WITH OCCASIONAL MVFR CONDITIONS WHERE SHOWER ACTIVITY DISTURBS THE NEAR SURFACE STRATUS AND FOG. WARMING MID DAY SHOULD ALLOW CEILINGS AND VISIBILITY TO IMPROVE A BIT WITH MVFR CONDITIONS PREVAILING DURING THE AFTERNOON...THOUGH POCKETS OF IFR WILL PERSIST. IFR OR LOWER CONDITIONS WILL QUICKLY RE-DEVELOP EARLY THIS EVENING AS PRECIPITATION INCREASES WITH ARRIVAL OF MAIN STORM SYSTEM. MOUNTAIN TOPS WILL SEE PERIODIC CLEARING ESPECIALLY THIS AFTERNOON BUT PASSES WILL BE OBSCURED TODAY. CHAMBERS && .PRELIMINARY POINT TEMP/POPS... TDY THU FRI SAT SUN MON TUE ------------------------------------------------------- BIL 045 032/044 029/060 038/061 042/065 045/072 048/077 7/R 98/O 10/U 01/U 11/U 10/U 11/U LVM 047 030/044 024/060 032/062 034/069 040/074 044/081 6/R 97/O 10/U 01/U 11/U 10/U 01/U HDN 047 034/046 028/061 037/064 041/068 044/073 046/077 7/R 98/O 20/U 01/U 11/U 11/U 11/U MLS 047 034/049 031/061 038/063 041/066 044/070 047/077 8/R 64/O 20/U 01/U 11/U 11/U 01/U 4BQ 047 033/045 028/058 037/063 040/065 044/071 047/076 8/R 78/O 21/U 01/U 11/U 10/U 11/U BHK 046 033/047 029/055 035/064 038/065 041/070 044/074 6/R 44/O 21/U 01/U 11/U 11/U 01/U SHR 049 032/040 022/057 032/063 036/067 041/073 044/079 6/R ++/O 31/U 01/U 11/U 11/U 11/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WINTER WEATHER ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO NOON MDT THURSDAY FOR ZONES 28-41-63. WINTER STORM WARNING IN EFFECT FROM 6 PM THIS EVENING TO 3 PM MDT THURSDAY FOR ZONES 56-66-67. WINTER STORM WARNING IN EFFECT FROM NOON TODAY TO 3 PM MDT THURSDAY FOR ZONE 68. WY...WINTER STORM WATCH IN EFFECT FROM THIS EVENING THROUGH THURSDAY MORNING FOR ZONES 98-99. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS TAUNTON MA
659 AM EDT WED SEP 10 2014 .SYNOPSIS... WEAK LOW PRESSURE PASSING SE OF NEW ENGLAND MAY BRING A FEW SHOWERS TO THE ISLANDS TODAY...OTHERWISE DRY WEATHER WILL PREVAIL. A COLD FRONT WILL SWING ACROSS THE REGION LATE THURSDAY AND EARLY FRIDAY...THEN STALL JUST OFFSHORE. A DISTURBANCE MOVING ALONG THIS FRONT SATURDAY MAY COME CLOSE ENOUGH TO RESULT IN SHOWERS. HIGH PRESSURE RETURNS WITH DRY AND COOLER WEATHER SUNDAY INTO TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 700 AM UPDATE... OVERALL TREND IN THE FORECAST REMAINS ON TRACK. HAVE MADE MINOR UPDATES TO ACCOUNT FOR CURRENT CONDITIONS. A FEW SPRINKLES MAY REACH ACK THIS MORNING. OTHERWISE EAST/NORTHEAST FLOW HAS ALLOWED FOR LOW STRATUS AND PATCHY FOG...ESP ALONG THE NORTH SHORE WHERE WIND SPEEDS ARE LESS. ANTICIPATE BOTH CLOUDS AND FOG TO LIFT DURING THE MORNING HOURS. PREVIOUS DISCUSSION.... MAIN BATCH OF SHOWERS REMAINS SE OF NANTUCKET AND EXPECT MOST OF IT TO REMAIN OFFSHORE TODAY. MODELS SEEM TO BE STRUGGLING WITH HOW CLOSE THESE SHOWERS GET TO SE NEW ENGLAND...BUT HRRR LOOKS REASONABLE IN GRAZING NANTUCKET THROUGH MID MORNING. DRY AIR AT MID LEVELS PER 00Z CHATHAM SOUNDING WILL PREVENT MUCH OF THIS FROM REACHING GROUND...IN FACT WE MAY JUST END UP WITH FEW SPRINKLES ON ISLANDS AND OUTER CAPE. LOW CLOUDS AND PATCHY FOG WILL PREVAIL ELSEWHERE THROUGH DAYBREAK DUE TO LIGHT ONSHORE FLOW...BUT WILL BREAK AFTER SUNRISE AND GIVE WAY TO PARTLY TO MOSTLY SUNNY SKIES. CONTINUED ONSHORE FLOW WILL KEEP HIGHS NEAR AVERAGE FOR MOST PART...MAINLY IN 70S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... EXPECT A RETURN OF LOW CLOUDS/FOG TONIGHT WHICH SHOULD BE MORE WIDESPREAD AS LOWER LEVELS MOISTEN WITH E/SE FLOW. MAY SEE AREAS OF DENSE FOG ALONG IMMEDIATE COAST. OTHERWISE SURFACE RIDGE KEEPS US DRY ASIDE FROM SPOTTY DRIZZLE. COLD FRONT APPROACHES NEW ENGLAND THU BUT SHOULD REMAIN TO OUR W. FLOW TURNS MORE S/SW IN ADVANCE OF FRONT WHICH WILL HELP SCOUR OUT LOW CLOUDS/FOG IN THE MORNING...EXCEPT AROUND S COAST...CAPE COD AND ISLANDS WHERE IT MAY PERSIST INTO AFTERNOON. INSTABILITY LOOKS MARGINAL AND MID LEVEL LAPSE RATES ARE WEAK... BUT ENOUGH TO INCLUDE MENTION OF THUNDER AHEAD OF FRONT. BETTER CHANCES ACROSS INTERIOR WHERE S FLOW OFF OCEAN IS LESS OF STABILIZING FACTOR. MODELS CONTINUE TO SHOW PLENTY OF MOISTURE AVAILABLE WITH PRECIPITABLE WATER VALUES NEAR 2 INCHES /+2 TO +3 STANDARD DEVIATION/...SO LOCALLY HEAVY RAINFALL CAN BE EXPECTED. HIGHS SHOULD REACH 70S AND LOWER 80S...AND IT WILL FEEL MORE SUMMERLIKE AS DEWPOINTS CLIMB WELL INTO 60S. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HIGHLIGHTS... * SCATTERED SHOWERS/ISOLATED T-STORMS THU PM INTO EARLY FRI * SLIGHT CHANGE FOR SHOWERS SAT PM/SUN * A TASTE OF AUTUMN TEMPERATURES NEXT WEEK OVERVIEW... LATEST MODEL AND ENSEMBLE GUIDANCE OVERALL SEEMS TO OFFER FAIRLY REASONABLE LARGER SCALE PATTERN EVOLUTION CONTINUITY. AN AMPLIFYING ERN PAC TROUGH AND WEST COAST RIDGE DRIFTING INTO WRN NOAM WILL SUPPORT MEAN MID-UPPER LEVEL TROUGHING OVER THE ERN HALF OF NOAM. THIS PATTERN...MORE TYPICAL OF THE COLD SEASON THAN LATE SUMMER OR EARLY FALL...SHOULD YIELD BELOW TO MUCH BELOW NORMAL TEMPS OVER MOST OF THE ERN 2/3 OF THE CONUS. HOWEVER...DETERMINISTIC MODEL RUNS FEATURE TOO MUCH INCONSISTENCY. SEVERAL RIPPLES WILL MOVE THROUGH THE FLOW THROUGH THE PERIOD WITH THE FIRST ONE BRINGING A COLD FRONT ON THURSDAY NIGHT/FRI MORNING. ANOTHER SHORTWAVE WILL PASS SAT/SAT NIGHT. THIS ONE CAUSES MORE UNCERTAINTY AS THE GFS IS HAVING CONVECTIVE FEEDBACK AND IS CREATING A 1-2 INCH BULLS-EYE OVER THE REGION...IN RETROSPECT THE EC IS PRODUCING VERY LIGHT QPF. LASTLY ANOTHER WAVE WILL MOVE TROUGH THE FLOW MONDAY NIGHT/TUESDAY. OVERALL HAVE MODERATE CONFIDENCE IN THE FORECAST AS THERE IS TO MUCH SPREAD BETWEEN THE DETERMINISTIC AND ENSEMBLE FORECASTS ESP IN SPECIFIC DETAILS IN THE FORECAST. DETAILS... THURSDAY NIGHT INTO FRIDAY... THE FOCUS IS ON A STRONG COLD FRONT THAT WILL PUSH ACROSS THE REGION THURSDAY NIGHT INTO FRIDAY MORNING. BOTH DETERMINISTIC AND ENSEMBLES KEEP THE INSTABILITY VALUES VERY LOW BUT BECAUSE OF THE STRENGTH OF THIS FRONT HAVE KEPT ISO MENTIONING OF THUNDER FOR THURSDAY. TIMED THE THUNDER POTENTIAL WITH THE BETTER K-VALUES AND LI. PRECIPITABLE WATERS INCREASE CONSIDERABLY...CLOSE TO 2-3 INCHES...WITH A STRENGTHENING SOUTHERLY FLOW. SOME OF THESE STORMS MAY PRODUCE HEAVY RAIN...WITH AN ISOLD FLASH FLOOD THREAT PRIMARILY IN URBANIZED AREAS. THEREFORE ALSO INCLUDED HEAVY RAIN WORDING FOR ANY THUNDERSTORM POTENTIAL. HIGH PRESSURE WILL QUICKLY SWING INTO THE AREA BY FRIDAY ALLOWING FOR THE DAY TO DRY OUT AND TEMPS TO REACH NEAR NORMAL. SATURDAY TO SATURDAY NIGHT... HIGH PRESSURE WILL BEGIN TO LIFT NORTHWARD ALLOWING FOR EASTERLY FLOW ON SATURDAY. BY THE LATE AFTERNOON/EVENING HOURS A COLD FRONT WILL PASS THROUGH REGION BRINGING ANOTHER CHANCE OF THUNDERSTORMS. AS MENTIONED BEFORE...THERE IS SIGNIFICANT DIFFERENCE BETWEEN THE DETERMINISTIC GUIDANCE WITH THE GFS PRODUCING A 1-2 INCH BULLS-EYE. WHILE THE EC IS DEVELOPING LIGHT QPF. APPEARS THE GFS IS RECEIVING CONVECTIVE FEEDBACK BUT BECAUSE BOTH ARE TRENDING TO MOVE PRECIP...HAVE INCREASED THE POTENTIAL TO CHANCE POP. SUNDAY INTO NEXT WEEKEND... A MODIFIED CANADIAN HIGH WILL THEN BUILD IN THROUGH EARLY NEXT WEEK BEFORE ANOTHER FRONTAL SYSTEM POSSIBLY IMPACTS THE AREA AROUND TUES OF NEXT WEEK. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. MODERATE CONFIDENCE THROUGH THU. AREAS OF MVFR/IFR CIGS/VSBYS THROUGH 12Z WITH BRIEF SHOWER/ SPRINKLE POSSIBLE NEAR NANTUCKET AND VINEYARD. CONDITIONS IMPROVE TO VFR AFTER 12Z FROM W TO E BUT MVFR CIGS MAY LINGER INTO EARLY AFTERNOON. CIGS/VSBYS LOWER AGAIN TONIGHT DUE TO PERSISTENT ONSHORE FLOW... THIS TIME TO IFR/LIFR ACROSS MUCH OF REGION. CONDITIONS SLOWLY IMPROVE TO VFR AGAIN THU MORNING...LAST ACROSS CAPE COD AND ISLANDS THU AFTERNOON...BUT SCATTERED SHOWERS/THUNDERSTORMS POSSIBLE ACROSS INTERIOR AFTER 18Z. MAY REACH BOS/PVD BY 22Z. KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS BUT LOWER CONFIDENCE ON EXACT TIMING. KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS BUT LOWER CONFIDENCE ON EXACT TIMING. OUTLOOK...FRIDAY THROUGH SUNDAY...MODERATE CONFIDENCE. FRIDAY...A PERIOD OF MVFR/IFR CONDITIONS POSSIBLE EARLY FRIDAY IN SCATTERED SHOWERS/ISOLATED THUNDERSTORMS AS A COLD FRONT SWEEPS THROUGH. OTHERWISE...VFR CONDITIONS EXPECTED FOR A GOOD PORTION OF THIS PERIOD. SATURDAY...LOW CONFIDENCE. MAINLY VFR. ONSHORE FLOW COULD ALSO RESULT IN IFR STRATUS AND FOG ACROSS PORTIONS OF THE EAST COAST...PARTICULARLY CAPE COD AND THE ISLANDS. SUNDAY...MODERATE CONFIDENCE. MAINLY VFR. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH THU. SCA REMAINS POSTED FOR OUTER WATERS MAINLY DUE TO 5-6 FT SEAS TODAY THROUGH THU. E/NE WINDS GRADUALLY SUBSIDE TODAY AS LOW PRESSURE PASSES WELL SE OF NEW ENGLAND...THEN S/SW WINDS DEVELOP THU AS COLD FRONT APPROACHES FROM GREAT LAKES. MAIN CONCERN IS PATCHY DENSE FOG TONIGHT INTO THU...ESPECIALLY ON S COASTAL WATERS. OUTLOOK...FRIDAY THROUGH SUNDAY...MODERATE CONFIDENCE. FRIDAY...MODERATE CONFIDENCE. A ROUND OF SCATTERED SHOWERS AND PERHAPS ISOLATED THUNDERSTORMS ARE EXPECTED EARLY FRIDAY MORNING AS A COLD FRONT PASSES THROUGH. WINDS WILL MAY REACH ABOVE 25 KT BEHIND THIS FRONT ALLOWING FOR SEAS TO APPROACH 5 FT AT TIMES ACROSS THE OUTER COASTAL WATERS. SMALL CRAFT ADVISORIES MAY BE NEEDED. SATURDAY...LOW CONFIDENCE. TIGHTENING PRESSURE GRADIENT AND APPROACHING COLD FRONT WILL HELP KEEP SEAS AND WINDS UP ON SATURDAY. SMALL CRAFT ADV MAY BE NEEDED. SUNDAY...STRONG COLD FRONT WILL PASS OVER THE WATERS IN THE MORNING. COLD AIR ALOFT WILL INCREASE SEAS AND WIND GUSTS ON SUNDAY LEADING TO THE POTENTIAL OF A SMALL CRAFT ADV. && .TIDES/COASTAL FLOODING... LAST HIGH TIDE JUST BEFORE MIDNIGHT PRODUCED 0.2 FT SURGE ALONG E MA COAST. SUBSEQUENT HIGH TIDES TODAY INTO THU ARE A BIT LOWER AND SURGE WILL BE MINIMAL...THEREFORE NO IMPACT IS EXPECTED. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ250- 254>256. && $$ SYNOPSIS...DUNTEN/JWD NEAR TERM...DUNTEN/JWD SHORT TERM...JWD LONG TERM...DUNTEN AVIATION...DUNTEN/JWD MARINE...DUNTEN/JWD TIDES/COASTAL FLOODING...JWD
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
1005 AM EDT WED SEP 10 2014 .UPDATE...EARLY MORNING RADAR TRENDS SHOW THE CLUSTER OF SHOWERS AND A FEW STORMS HAVE DECREASED IN COVERAGE AND INTENSITY OVER THE SE GA COASTAL WATERS AND THE SE GA COASTAL COUNTIES. STILL A FEW MODERATE SHOWERS NEAR THE BRUNSWICK AREA THAT ARE LIFTING SLOWLY NWD. SATELLITE AND SFC DATA AND HRRR MODEL SHOW THE TAIL END OF A FRONTAL BOUNDARY ACROSS THE WRN ATLC THAT EXTENDS WWD TO ABOUT THE COASTAL SE GA AND TO PERHAPS AROUND WAYCROSS AND THEN DIFFUSE THEREAFTER INLAND S GA. PATCHY TO AREA OF FOG HAVE DISSIPATED AFTER SOME VSBY DROPPED TO 1/4 MILE BRIEFLY OVER PORTIONS OF SE GA. FOR REST OF TODAY...A FEW TWEAKS TO THE FORECAST TO BUMP UP TEMPS A BIT MORE AND ADJUST POPS. THERE MAY BE SOME ENHANCED PRECIP POTENTIAL OVER THE NEXT FEW HOURS OVER EXTREME NE FL JUST S OF THE WEAK FRONTAL BOUNDARY...BUT NO MORE THAN 40% CHANCE FOR NOW FOR NASSAU AND DUVAL COUNTIES. JUST NOW SEEING A FEW SHOWERS POP UP ABOUT 20-30 MILES E OF FERNANDINA BEACH. OTHERWISE...WITH MID LEVEL HIGH PRES OFFSHORE THE E COAST SEA BREEZE WILL HAVE NO PROBLEMS MOVING INLAND THIS AFTERNOON WITH BEST COVERAGE OF SEA BREEZE-INFLUENCED SHOWERS AND A FEW STORMS OVER INLAND NE FL WHERE 30-40% SHOULD BE MORE THAN ADEQUATE TO COVER THE PRECIP POTENTIAL. ONLY 20-30% ADVERTISED FOR SE GA ATTM REST OF TODAY. MODIFIED MODEL SOUNDINGS PRODUCE SBCAPE OF ABOUT 2000-2500 J/KG WITH POTENTIAL DOWNBURST GUST TO 35 KNOTS (40 MPH)...WHICH WILL BE MOST LIKELY OVER INLAND NE FL AFTER 2 PM TODAY. && .AVIATION...PREVAILING VFR WITH SCT-LCL BROKEN CUMULUS 2500-3500 FT AND MID LEVEL CLOUDINESS AT TIMES. A FEW SHOWERS POSSIBLE VICINITY OF NE FL COASTAL TAFS AS DAYTIME HEATING COMMENCES. HAVE VCTS FOR GNV LATER THIS AFTERNOON. NO TEMPO GROUPS NEEDED ATTM. WEAK AND VARIABLE WINDS NEXT FEW HOURS THEN BECOME ELY TO SE THIS AFTERNOON. && .MARINE...LIGHT WINDS WILL BECOMING SE TO E AROUND 10 KT AND SEAS OF 2-3 FT. RIP CURRENTS: LOW RISK OF RIP CURRENTS TODAY AND THURSDAY. && .PRELIMINARY POINT TEMPS/POPS... AMG 90 71 93 73 / 20 20 20 10 SSI 85 76 86 75 / 30 10 10 10 JAX 88 74 90 73 / 30 10 20 10 SGJ 86 75 87 74 / 20 10 20 10 GNV 90 72 90 71 / 30 30 40 20 OCF 90 73 90 72 / 30 30 30 30 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...NONE. && $$ SHASHY/GUILLET
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
814 AM EDT WED SEP 10 2014 .SYNOPSIS... A PRESSURE RIDGE EXTENDING THROUGH THE FORECAST AREA TODAY WILL BE OFF THE COAST THURSDAY. A COLD FRONT WILL MOVE INTO THE FORECAST AREA FRIDAY AND STALL. && .NEAR TERM /THROUGH TONIGHT/... THE PRESSURE RIDGE EXTENDING INTO THE FORECAST AREA WILL SHIFT OFF THE COAST THIS AFTERNOON AND TONIGHT. THERE WILL BE WEAK CONVERGENCE ASSOCIATED WITH THE REMNANTS OF THE FRONT. THERE WERE A FEW SHOWERS JUST SOUTH OF THE FORECAST AREA EARLY THIS MORNING. SOME OF THE HIGH-RESOLUTION MODELS DISPLAY ISOLATED SHOWERS IN MAINLY THE SOUTH PART OF THE FORECAST AREA THIS AFTERNOON AND TONIGHT. HOWEVER...THE 08Z HRRR MAINTAINED DRY CONDITIONS THROUGH TODAY. UPPER-RIDGING OVER THE AREA SHOULD HELP KEEP MOISTURE SHALLOW WITH MID-LEVEL CAPPING. WE KEPT POPS LESS THAN 20 PERCENT. NOCTURNAL COOLING WITH SUFFICIENT LOW-LEVEL MOISTURE AND DRY AIR ALOFT SHOULD HELP SUPPORT AREAS OF FOG LATE TONIGHT. THE TEMPERATURE GUIDANCE WAS CLOSE. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... HIGH PRESSURE WILL PUSH INTO THE ATLANTIC BASIN THURSDAY AS THE NEXT COLD FRONT TRACKS TOWARD THE AREA. THE COLD FRONT WILL CROSS THE OHIO AND TN VALLEYS THURSDAY THEN MOVE INTO THE UPSTATE THURSDAY NIGHT. THIS WILL PRODUCE INCREASING CLOUDS AND WITH SOUTHERLY WINDS PUSHING MOISTURE BACK INTO THE AREA. PWAT VALUES WILL INCREASE...WITH VALUES BETWEEN 1.5 AND 2.00 INCHES. ALTHOUGH THE MODELS INDICATE A POTENTIAL FOR SHOWERS AND THUNDERSTORMS THURSDAY AFTERNOON KEPT SLIGHT CHANCE POPS AS DRY AIR ALOFT WILL REMAIN ALONG WITH A MID-LEVEL CAP. POPS WILL INCREASE SLOWLY THURSDAY NIGHT AS THE FRONT MOVES CLOSER TO THE FORECAST AREA WITH THE BEST CHANCE ACROSS THE NORTHWESTERN SECTION. TEMPERATURES THURSDAY WILL BE IN THE LOWER 90S GIVEN SLIGHT WARM ADVECTION AHEAD OF THE COLD FRONT. SHOULD SEE OVERNIGHT LOWS IN THE LOWER 70S. && .LONG TERM /FRIDAY THROUGH TUESDAY/... MODELS CONTINUE IN GOOD AGREEMENT THROUGH THE LONG TERM. THE COLD FRONT WILL SLOW AS IT MOVES IN THE FORECAST AREA FRIDAY AND STALL ACROSS THE AREA FRIDAY NIGHT THROUGH TUESDAY. WITH HIGH PRESSURE BUILDING INTO THE SOUTHERN GREAT LAKES REGION SATURDAY COOLER AND DRIER AIR WILL BEGIN MOVING SOUTHWARD THROUGH THE EASTERN US AND BEGIN FILTERING INTO THE FORECAST AREA LATE IN THE WEEKEND. WITH THE FRONT ACROSS THE REGION CHANCES OF SHOWERS AND THUNDERSTORMS WILL CONTINUE WITH THE HIGHEST POPS CURRENTLY EXPECTED FRIDAY THROUGH SATURDAY...WITH SOME UNCERTAINTY IN POPS FOR MONDAY AND TUESDAY. TEMPERATURES THROUGH THE LONG TERM WILL BE NEAR NORMAL THROUGH FRIDAY NIGHT WITH BELOW NORMAL READINGS EXPECTED FOR SATURDAY AND BELOW NORMAL FOR SUNDAY THROUGH TUESDAY. && .AVIATION /11Z WEDNESDAY THROUGH SUNDAY/... EXPECT MAINLY VFR CONDITIONS THROUGH THE EVENING WITH GENERALLY HIGH PRESSURE RIDGING INTO THE AREA. WEAK CONVERGENCE AND MOISTURE ASSOCIATED WITH THE REMNANTS OF A FRONT COULD POSSIBLY HELP SUPPORT SHOWERS THIS AFTERNOON AND TONIGHT BUT THE CHANCE IS VERY LOW BECAUSE OF UPPER- LEVEL RIDGING WITH SHALLOW MOISTURE AND MID-LEVEL CAPPING. NOCTURNAL COOLING WITH SUFFICIENT LOW-LEVEL MOISTURE AND DRY AIR ALOFT SHOULD HELP SUPPORT AREAS OF FOG LATE TONIGHT AND EARLY THURSDAY MORNING. .EXTENDED AVIATION OUTLOOK...A FRONTAL SYSTEM WILL MOVE INTO THE AREA THURSDAY NIGHT AND FRIDAY. THE FRONT WILL THEN STALL. WIDESPREAD MVFR OR IFR CONDITIONS WILL LIKELY BE ASSOCIATED WITH THIS FEATURE THURSDAY NIGHT THROUGH SUNDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1150 AM EDT WED SEP 10 2014 .UPDATE... ISSUED AT 1149 AM EDT WED SEP 10 2014 GENERALLY MINOR TWEAKS TO THE GOING FORECAST...LARGELY WITH PINNING DOWN THE LOCATIONS OF THE HEAVIEST PRECIPITATION AND THEN WINDS FOR THIS AFTERNOON AND TONIGHT BEHIND THE LOW. AS FOR THE RAIN...ESSENTIALLY SEEING TWO AREAS OF PRECIPITATION...ONE OVER THE EAST ALIGNED WITH THE BROAD 850-500MB WARM AIR ADVECTION LIFTING TO THE NORTHEAST AHEAD OF THE LOW CENTERED OVER SOUTH CENTRAL WISCONSIN. EXPECT THAT AREA TO CONTINUE PUSHING TO THE NORTHEAST THROUGH THE DAY AND LARGELY DEPARTING BY LATE AFTERNOON. THE SECOND AREA IS FARTHEST TO THE WEST AND TIED TO THE 850-700MB FGEN AREA TO THE NORTHWEST OF THE MID LEVEL LOW. OBSERVER REPORTS INDICATE THIS AREA OF RAIN PRODUCING AROUND 0.5-0.75IN EVERY THREE HOURS AND THAT MATCHES DUAL POL INSTANTANEOUS PRECIP RATES. ALTHOUGH THIS AREA HAS BEEN PIVOTING AND SLOW TO MOVE THIS MORNING...IT IS EXPECTED TO SHIFT MORE TO THE EAST-NORTHEAST THIS AFTERNOON AS THE LOW QUICKLY MOVES NORTHEAST THROUGH NORTHERN LAKE MICHIGAN. STILL HAVE THE FLOOD WATCH IN PLACE AND THAT SEEMS REASONABLE OVER THE WEST (WITH THE ADDED PRECIP FROM OVERNIGHT PUSHING TOTALS OVER 2 INCHES IN SOME LOCATIONS). FROM MARQUETTE/DICKINSON COUNTY EAST...THINK THE POTENTIAL FOR FLOODING IS PRETTY LIMITED BUT WILL LEAVE WATCH IN PLACE AT THIS TIME. FINALLY FOR WINDS...MAIN ADJUSTMENTS WERE FOR AREAS OVER THE EAST AND NEAR LAKE MICHIGAN. EXPECT THE COMBINATION OF STRONG COLD AIR ADVECTION BEHIND THE LOW AND QUICK PRESSURE RISE TO LEAD TO GALES AND HAVE ISSUED A GALE WARNING FOR OUR LAKE MICHIGAN ZONES. DO HAVE A LITTLE CONCERN THAT GUSTS WILL BE NEAR 40-45MPH BRIEFLY LATE THIS AFTERNOON INTO THE EVENING NEAR THE LAKE SUPERIOR SHORELINE AND POTENTIALLY AT TIMES ELSEWHERE INLAND. THE OTHER AREA WAS OVER THE KEWEENAW PENINSULA...ALTHOUGH THE FORECAST WAS IN DECENT SHAPE...LATEST OBS AT KP59 INDICATE WINDS GUSTING TO NEAR WIND ADVISORY CRITERIA. WITH THE CENTRAL LAKE SUPERIOR BUOY GUSTING ABOVE 40KTS AND OTHER SITES NEAR WIND ADVISORY CRITERIA...WILL ISSUE A WIND ADVISORY FOR KEWEENAW AND NORTHERN HOUGHTON COUNTIES THROUGH THE EVENING HOURS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 533 AM EDT WED SEP 10 2014 LIGHT TO AT TIME HEAVY RAIN CONTINUES TO FALL OVER THE W THIRD OF UPPER MI THIS MORNING...ASSOCIATED WITH THE SFC TROUGH THAT PUSHED OVERHEAD EARLY THIS MORNING THE 500MB SHORTWAVE CROSSING WI...AND THE DEEPENING SFC LOW RIDING UP ALONG THE TROUGH NEARING FROM IA. THE LATEST SATELLITE AND RUC ANALYSIS SHOWS THIS INITIAL N SWATH OF MOISTURE EJECTING NE ACROSS THE CWA...WITH THE EFFECTS OF THE SW TO NE 100KT 250MB JET NEARING FROM THE PLAINS. THE SECONDARY AREA OF CLOUDS WILL BE IMPACTING THE E HALF OF THE CWA LATER THIS MORNING AND INTO THE AFTERNOON HOURS. EXACT RAINFALL TOTALS REMAIN TRICKY AS THERE ARE 2 AREAS OF THOUGHT. THE LATEST 06Z NAM PAINTS AN ADDITIONAL 1-2IN OVER CENTRAL AND E UPPER MI LATE THIS MORNING THROUGH EARLY THIS AFTERNOON. HOWEVER...THE 00Z GFS IS PUSHING MUCH OF THE MOISTURE JUST TO OUR E. HAVE GONE WITH A MIDDLE OF THE ROAD SOLUTION FOR THE MOMENT...KNOWING THAT CONVECTION TO THE SOUTH COULD STILL HURT THE INFLOW OF MOISTURE UP OUR WAY. STILL...ADDITIONAL SHOWERS CROSSING THE CWA THIS AFTERNOON WITH BE FACED WITH STIFF N ONSHORE FLOW...RESULTING IN A SLOWER N PROGRESSION AND OVERALL UPSLOPE ENHANCEMENT. SEE THE HYDROLOGY SECTION FOR MORE DETAILS ABOUT PRECIPITATION FOR THE REST OF TODAY. RAIN/RAIN SHOWERS WILL CONTINUE THROUGH TONIGHT...MAINLY ACROSS THOSE UPSLOPE AREAS OF CENTRAL UPPER MI. ADDITIONAL RAINFALL MAY ADD UP TO 0.25IN OR MORE ACROSS THE HURON MOUNTAINS. FCST MODELS ARE CONTINUING TO GO WITH THE SFC LOW TRACKING ACROSS N LOWER MI LATE THIS AFTERNOON...BEFORE EXITING INTO S ONTARIO AND W QUEBEC LATE THIS EVENING. TEMPERATURES WILL REMAIN TRICKY...AS THEY FALL W AND STILL RISE A COUPLE OF DEGREES AFTER SUNRISE E. KEPT THE WIND FCST VERY SIMILAR TO THE LAST COUPLE OF DAYS...WITH N-NNW GUSTS NEARING 35KTS FROM AROUND 18Z TODAY TO 08Z TONIGHT. AN SPS MAY BE NEEDED FOR THE W HALF AND HIGHER TERRAIN OF THE KEWEENAW PENINSULA...OR LOW END WIND ADVISORY TO HIGHLIGHT THE STRONG WINDS ON TOP OF SATURATED SOILS THAT MAY MORE EASILY UPROOT TREES THANKS TO THE ABUNDANT LEAVES. AS FOR THE OVERNIGHT HOURS...EXPECT SLOWLY DIMINISHING WINDS LATE AND COLD AIR TO FILTER IN WITH 850MB TEMPS OF -2 TO +4C BY DAYBREAK THURSDAY. DEPENDING ON HOW FAST RAIN CAN GET OUT OF THE INTERIOR AREAS ALONG THE WI BORDER...MID 30S LOWS WILL NOT BE OUT OF THE QUESTION. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 359 AM EDT WED SEP 10 2014 MAIN FCST CONCERNS IN THE LONG TERM FOCUS ON HOW QUICKLY ON THU CLDS AND SHOWERS ASSOCIATED WITH THE WED LO PRES WL EXIT THE CWA...TEMPS AND THE POTENTIAL FOR FROST ON THU NGT AND THEN ON POPS ACCOMPANYING THE PASSAGE OF ANOTHER DISTURBANCE THRU THE LOWER LKS ON FRI INTO SAT. SINCE AN UPR TROF WL DOMINATE ERN NAMERICA THRU NEXT WEEK... EXPECT BLO NORMAL TEMPS TO PREVAIL DURING THE EXTENDED PERIOD. THU...AS DEPARTING LO PRES OVER FAR SW QUEBEC AT 12Z THU SHIFTS TO THE ENE...STEADY N LLVL FLOW IS PROGGED TO WEAKEN AND BECOME MORE ACYC UNDER GENERAL DEEP LYR QVECTOR DVGC LEFT IN THE WAKE OF THE EXITING SHRTWV AND RDG AXIS EXPANDING TO THE E OF SFC HI CENTER IN THE NRN PLAINS. EXPECT PLENTY OF CLDS IN THE MRNG WITH SHOWERS MAINLY NEAR LK SUP ASSOCIATED WITH CHILLY LINGERING CYC FLOW OVER THE RELATIVELY WARM LK SUP WATERS. BUT WITH INCRSG SUBSIDENCE/ACYC FLOW IN THE PRESENCE OF DAYTIME HEATING...EXPECT THE SHOWERS TO DIMINISH AND THE CLD PATTERN TO SHIFT TO MORE INLAND SC COVERAGE UNDER THE H85 THERMAL TROF AND SUBSIDENCE INVRN SINKING TOWARD H85-9. H85 TEMPS IN THE ZERO TO -2C RANGE WL SUPPORT WELL BLO NORMAL HI TEMPS MAINLY IN THE UPR 40S/50S...COOLEST OVER THE HIER TERRAIN OF THE NW HALF. THU NGT...UNDER BLDG HI PRES WITH LOSS OF DAYTIME HEATING...EXPECT LINGERING SC TO DSPT IN THE EVNG AND GIVE WAY TO AT LEAST A PERIOD OF MOCLR SKIES AND LGT WINDS. WITH PWAT UNDER 0.5 INCH...TEMPS SHOULD FALL OFF STEADILY. THE ONE LIMITING FACTOR WL BE HOW QUICKLY HI CLDS IN ADVANCE OF SHRTWV MOVING THRU THE NRN PLAINS WL INVADE THE UPR LKS. SUSPECT THE COLD SPOTS OVER THE INTERIOR WL SEE TEMPS FALLING AOB 32...BUT WL HOLD OFF ON ANY KIND OF FREEZE WATCH/FROST HEADLINE GIVEN ACTIVE SHORT TERM...MARGINALLY LO ENUF FCST TEMPS AND COVERAGE OF THOSE REALLY LO TEMPS UNDER SOME INCRSG HI CLDS. FRI THRU SAT...ALTHOUGH THERE IS GOOD MODEL AGREEMENT ON THE TIMING AND TRACK OF A FAIRLY VIGOROUS SHRTWV THAT IS FCST TO MOVE E FM THE NRN ROCKIES ON THU AFTN THRU THE NCENTRAL PLAINS AND ACROSS THE LOWER LKS FRI NGT/SAT...THERE ARE SOME FAIRLY LARGE DIFFERENCES IN THE MSLP FIELDS AND QPF. THE 09/12Z ECWMF CONTINUES TO BE THE MODEL THAT SHOWS THE MORE IMPRESSIVE PRES FALL. WITH A DEEPER SFC REFLECTION...THE ECMWF ALSO SHOWS MORE EXPANSIVE MID LVL MSTR/PCPN EXTENDING INTO ALL OF UPR MI DURING FRI NGT/SAT MRNG. GIVEN THE POSITIVE TILT TO THE SHRTWV....EXPANSIVE HI PRES THAT IS FCST TO EXTEND FM THE NRN PLAINS INTO THE UPR LKS IN ADVANCE OF THIS SHRTWV AND DRY/STABLE NATURE OF THE ANTECEDENT AIRMASS /PWAT AOB 0.5 INCH WITH STRONG SUBSIDENCE INVRN BTWN H8-7/...SUSPECT THE NON-ECMWF MODELS SHOWING LESS SFC RESPONSE ARE ON THE RIGHT TRACK. HAVE THUS CHOSEN TO MAINTAIN ONLY LO CHC POPS...HIEST OVER THE SRN CWA CLOSER TO THE SHRTWV TRACK/AREA OF SHARPER DEEP LYR QVECTOR CNVGC. THICKER CLDS/THESE POPS WL ARRIVE ON FRI AFTN AS THE DISTURBANCE SLIDES INTO THE UPR MS RIVER VALLEY. ONCE THE SHRTWV PUSHES TO THE E ON SAT MRNG...TRAILING SHRTWV RDG/DRIER AIRMASS WL BRING A RETURN TO DRY WX/CLRG. WITH H85 TEMPS IN THE ZERO TO -2C RANGE DURING THIS TIME...THE WX WL BE UNSEASONABLY COOL. IF SKIES CLR FAST ENUF LATE FRI NGT...NOT OUT OF THE QUESTION THERE COULD BE SOME FROST OVER THE INTERIOR W ARND SUNRISE ON SAT. EXTENDED...AFTER A DRY PERIOD ASSOCIATED WITH SFC HI PRES PASSING THRU THE LOWER LKS ON SAT NGT...ANOTHER CNDN SHRTWV DIGGING THRU THE MEAN UPR TROF CENTERED OVER HUDSON BAY AND INTO THE NCENTRAL CONUS WL BRING A CHC OF MORE SHOWERS FOR SUN THRU MON. THIS DISTURBANCE WL BE MSTR DEPRIVED...SO NO HEAVY RA IS LIKELY. HI PRES MOVING E UNDER THE RISING HGTS IN THE WAKE OF THIS DISTURBANCE SHOULD BRING A RETURN OF DRY WX FOR TUE. WITH THE MEAN TROF IN PLACE...TEMPS ACRS UPR MI WL AVG BLO NORMAL DURING THIS TIME. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 603 AM EDT WED SEP 10 2014 OFF AND ON RAIN AND BR/FG HAVE BEEN THE TREND OVERNIGHT. ONCE THE RAIN HAS ENDED IFR TO VLIFR CEILINGS HAVE DEVELOPED. INCREASING WINDS THIS MORNING SHOULD HELP LIMITED THE BR. HOWEVER...LOW CEILINGS WILL STILL BE POSSIBLE WITH ANY MODERATE RAIN THAT DEVELOPS. LOOKING AT UPSTREAM CONDITIONS...LIFR CEILINGS WILL LIKELY DOMINATE THE DAY AT IWD AND CMX. STEADIER RAIN WILL MOVE INTO SAW OVER THE NEXT FEW HOURS. LOOK FOR STRONG WINDS DEVELOPING W TO E THIS MORNING...WITH GUSTS OVER 30KTS POSSIBLE AT CMX FROM 19Z THIS AFTERNOON TO 04Z THURSDAY. IWD MAY BE LIMITED TO GUSTS AROUND 20KTS...WHILE THE N WINDS GUST BETWEEN 25 AND 30KTS FROM 21Z TO 09Z THURSDAY AT SAW AND KEEP LAKE EFFECT/ENHANCED RAIN SHOWERS GOING THROUGH 12Z THURSDAY. DRIER AIR WILL SLOWLY WORK IN FROM THE W...WITH ONLY A CHANCE OF SHOWERS AT CMX AND IWD BY DAYBREAK THURSDAY. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 359 AM EDT WED SEP 10 2014 AS A DEEP LO PRES MOVES NE THRU THE UPPER MIDWEST AND ACROSS NORTHERN LOWER MI THIS EVENING ON ITS WAY INTO SE CANADA TONIGHT...THE NE GALES AFFECTING WESTERN LAKE SUPERIOR WILL SPREAD E OVER THE REST OF THE LAKE. EXPECT NNE GALES AS HI AS 40-45 KTS TODAY INTO TONIGHT BEFORE THE LO PRES SHIFTS FAR ENOUGH TO THE E AND THE GALES DIMINISH W TO E TONIGHT. AS HI PRES BUILDS TOWARD LAKE SUPERIOR FROM THE PLAINS ON THU...LINGERING N WINDS UP TO 25-30 KTS IN THE MORNING WILL DIMINISH W-E TO UNDER 15-20 KTS BY THE EVENING. RELATIVELY LIGHT WINDS UNDER 20 KTS WILL THEN DOMINATE THRU THE WEEKEND UNDER A RELATIVELY WEAK PRES GRADIENT. && .HYDROLOGY... ISSUED AT 426 AM EDT WED SEP 10 2014 RAINFALL OVER THE W THIRD OF UPPER MI HAS BEEN CONVECTIVELY ENHANCED...WITH RAINFALL RATES BRIEFLY RISING TO NEAR 6IN PER HOUR. WITH THE QUICK MOVEMENT TO THE N JUST OVER 20KTS THAT AMOUNT WAS NOT REALIZED. RADAR ESTIMATES THROUGH 08Z HAVE THE HIGHEST AMOUNTS OVER NW GOGEBIC AND ALONG THE E ONTONAGON/W HOUGHTON COUNTIES...WITH 1.5 TO 2.25IN. SOME LOCAL RIVERS CONTINUE TO RESPOND TO THE RAINFALL A FEW DAYS AGO...AND ARE RISING AT AN INCREASED RATE DO TO THE CURRENT RAIN. SPECIFICALLY THIS INCLUDES THE SOUTH BRANCH OF THE ONTONAGON RIVER AT EWEN /WHICH GIVEN THE TREND WILL SEE A SLOW RISE FOR THE NEXT SEVERAL DAYS/. THE MIDDLE BRANCH OF THE ONTONAGON RIVER AT PAULDING IS ALSO SLOWLY ON THE RISE. OTHERWISE AN AVERAGED 0.5IN HAS FALLEN W OF A LINE FROM IRON RIVER TO BARAGA. LITTLE RAIN HAS FALLEN E OF THIS LINE...WHICH WILL CHANGE OVER THE NEXT COUPLE OF HRS AS ADDITIONAL SHOWERS NEAR FROM WI. THUNDERSTORMS ARE MINIMAL OVER WI...AND PRECIP IS SLOWER THAN ORIGINALLY ANTICIPATED. HAVE BACKED OFF ON THE STORM TOTAL PRECIP OVER THE E THIRD OF THE FCST AREA AS A RESULT. EXPECT THE TRADITIONAL URBAN/SMALL STREAM FLOODING TO BE A SIGNIFICANT POSSIBILITY IN THE TYPICAL POOR DRAINAGE AREAS OF ESC IF A PERIOD OF HEAVIER DOWNPOURS DEVELOP WITH RAINFALL RATES CLOSE TO AN 0.5-1.0 INCH PER HOUR. N CNTRL UPPER MI WILL STILL LIKELY SEE SOME UPSLOPE LAKE ENHANCEMENT TODAY-TONIGHT. THE FLOOD WATCH REMAINS POSTED FOR MUCH OF W AND CENTRAL UPPER MI FOR TODAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... FLOOD WATCH UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR MIZ001>006-009>013-084. LAKE SUPERIOR... GALE WARNING FROM 8 PM THIS EVENING TO 8 AM EDT THURSDAY FOR LSZ251-267. GALE WARNING UNTIL 5 AM EDT THURSDAY FOR LSZ246>250-265-266. GALE WARNING UNTIL 4 AM EDT THURSDAY FOR LSZ243>245-264. GALE WARNING UNTIL 2 AM EDT /1 AM CDT/ THURSDAY FOR LSZ240>242- 263. GALE WARNING UNTIL 11 PM EDT /10 PM CDT/ THIS EVENING FOR LSZ162. LAKE MICHIGAN... GALE WARNING UNTIL 8 AM EDT THURSDAY FOR LMZ221-248-250. && $$ UPDATE...SRF SHORT TERM...KF LONG TERM...KC AVIATION...KF MARINE...KC HYDROLOGY...KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
543 AM CDT WED SEP 10 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 327 AM CDT WED SEP 10 2014 MODERATE TO HEAVY RAIN CONTINUES OVER MUCH OF EAST CENTRAL MN AND WEST CENTRAL WISCONSIN. ALTHOUGH THE GREATER MOISTURE TRANSPORT HAS EXITED TO THE SOUTHEAST OF THE AREA...FAIRLY STRONG MID LEVEL FRONTOGENESIS REMAINS OVER TWO SPECIFIC AREAS OF THE CWA. ONE OVER EAST CENTRAL MN AND NORTHWEST WISCONSIN AND THE OTHER DEVELOPING TO THE SOUTHEAST...MOVING NOW INTO WEST CENTRAL WISCONSIN. THE RUC AND NAM SHOW THIS GRADUALLY WEAKENING AND LIFTING OFF TO THE EAST DURING THE MORNING. THIS SHOULD TAKE THE RAIN WITH IT. THE THREAT OF PONDING WATER REMAINS MAINLY ACROSS WEST CENTRAL WISCONSIN INTO THE MORNING. COLLABORATION WITH SURROUNDING OFFICES DID YIELD THE CONTINUATION OF THE FLOOD WATCH INTO WEST CENTRAL WISCONSIN. TODAYS HIGH TEMPERATURES WILL LIKELY OCCUR THIS MORNING AS WELL. THEY MAY CONTINUE TO DROP OFF THROUGH MID MORNING OR SO BEFORE LEVELING OFF INTO THE AFTERNOON. STRONG NORTH WINDS RE EXPECTED TO DEVELOP EAST AS LOW LEVEL CAA SPREADS OVER THE REGION. CLOUDS ARE EXPECTED TO HANG TOUGH OVER MUCH OF THE AREA INTO THE NIGHT. THERE IS SOME INDICATION THAT IN THE WAKE OF THE TROUGH...SUBSIDENCE COULD BE STRONG ENOUGH TO ERODE THE LOWER CLOUD COVER. WINDS WILL SLOWLY DIMINISH AS THE LOW CONTINUE TO LIFT EAST/NORTHEAST INTO THE NIGHT. IT SHOULD COOL RAPIDLY IF BREAKS DO DEVELOP INTO THE NORTH CENTRAL CWA DURING THE NIGHT. SOME UPPER 30S POSSIBLE WHERE THIS OCCURS. READINGS IN THE LOWER 40S SHOULD REMAIN ELSEWHERE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 327 AM CDT WED SEP 10 2014 THE LONG TERM FORECAST WILL FEATURE THE PASSAGE OF A SHORTWAVE TROUGH AT THE BEGINNING OF THE PERIOD...FOLLOWED BY BRIEF SEMI- ZONAL FLOW OVER THE WEEKEND...AND THEN A PATTERN TRANSITION TO WESTERN RIDGING AND EASTERN TROUGHING THROUGH THE FIRST HALF OF NEXT WEEK. ON THURSDAY...A BROAD SURFACE HIGH BECOMES ESTABLISHED ACROSS THE NATION/S MIDSECTION...WHILE A WEAK SHORTWAVE SLIDES EAST/SOUTHEAST ACROSS THE AREA FROM THE NORTHERN/CANADIAN ROCKIES. WHILE THE BETTER FORCING AND MORE PLENTIFUL MOISTURE WILL LIE SOUTH OF THE FORECAST AREA...COULD SEE A FEW SHOWERS SNEAK INTO SOUTHERN MN AND WEST CENTRAL WI LATE THURSDAY NIGHT AND FRIDAY. TEMPERATURES WILL BE COOL...WITH HIGHS IN THE 50S ON THURSDAY AND FRIDAY...AND LOWS DIPPING INTO THE MID TO UPPER 30S. DEPENDING ON HOW THE CLEARING GOES AND WINDS...COULD POSSIBLY SEE SOME FROST ON SATURDAY MORNING. SATURDAY LOOKS TO HAVE THE HIGHEST POTENTIAL TO BE AN ENTIRELY DRY DAY...AS SURFACE HIGH PRESSURE PREVAILS AND IN THE ABSENCE OF ANY MID/UPPER DISTURBANCES. SUNDAY BRINGS THE ARRIVAL OF WEAK SHORTWAVE ENERGY IN THE BASE OF THE MANITOBA/ONTARIO TROUGH. MOISTURE AND FORCING ARE THE MOST ROBUST NORTH AND EAST OF THE FORECAST AREA...BUT SUFFICIENT TO WARRANT 20 POPS LOCALLY. ON MONDAY...THINGS START TO DRY OUT WITH THE PATTERN EVOLUTION TO WESTERN RIDGING. OVERALL...SHOULD BE DRY WITH SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH MID-WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 534 AM CDT WED SEP 10 2014 IFR/LIFR CONDITIONS ACROSS MOST TAF SITES THIS MORNING GRADUALLY IMPROVING TO MVFR CIGS BY LATE AFTERNOON/EVENING. INTENSITY OF RAIN SHIELD DIMINISHING AS SURFACE LOW/FORCING MOVES EAST. WILL END RAIN FROM WEST TO EAST DURING THE MORNING IN MN AND LATEST IN WESTERN WI SITES. NORTH WINDS TO REMAIN STRONG MOST AREAS DURING THE DAY...DIMINISHING THIS EVENING. WILL TREND TO VFR INTO THE EVENING WITH THE EXCEPTION OF THE WISCONSIN SITES. KMSP...IFR IMPROVING TO MVFR THIS AFTERNOON/22Z. WILL KEEP CIGS BELOW 1700 FT FOR NOW. LIGHT RAIN TO END BY LATE MORNING. WILL TREND CIGS TO VFR THIS EVENING WITH DIMINISHING WINDS. /OUTLOOK FOR KMSP/ WED NITE...MVFR EARLY THEN VFR. WINDS N AT 5 TO 10KTS. THU...VFR. WINDS NW AT 10G15KTS. FRI...VFR. WINDS NW AT 10G15KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR WIZ015-016- 023>028. && $$ SHORT TERM...DWE LONG TERM...LS AVIATION...DWE
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
930 AM MDT WED SEP 10 2014 .UPDATE... OVERALL FORECAST IN GOOD SHAPE...BUT HAVE ADDED SOME DETAIL FOR THE AFTERNOON. MESOSCALE MODELS IN GOOD AGREEMENT THAT WESTERN AND CENTRAL ZONES WILL SEE A BREAK IN PRECIPITATION THIS AFTERNOON BEFORE NEXT STRONG WAVE DROPS SOUTH INTO OUR REGION LATE TODAY AND TONIGHT. BROKE UP AFTERNOON TO REFLECT THIS BY LOWERING POPS TO JUST CHANCE VARIETY BEFORE TRENDING TO MUCH HIGHER POPS BY EVENING. ALREADY SOME SNOW AT JUDITH GAP...SO ATMOSPHERE A LITTLE AHEAD OF MODELS FOR SUPPORTING SNOW. MAIN FORECAST ISSUES FOR THE AFTERNOON PACKAGE INVOLVE WHETHER TO ADD HIGHLIGHTS FOR PARK COUNTY/PARADISE VALLEY...BIG HORN COUNTY/SOUTHERN ROSEBUD...AND HOW TO HANDLE SHERIDAN COUNTY WHERE CONCERN IS OVER HOW SOON/IF THEY CHANGE OVER TO SNOW RIGHT IN SHERIDAN. BT && .SHORT TERM...VALID FOR TDY AND THU... MAIN FORECAST ISSUE REVOLVES AROUND POTENTIAL SNOW EVENT TONIGHT INTO THURSDAY. DYNAMIC UPPER LOW DROPPING ALONG THE SPINE OF THE CANADIAN ROCKIES...WITH AN IMPRESSIVE 120KT H3 NWLY JET ANALYZED IN CENTRAL BRITISH COLUMBIA. CLOUD TOPS IN STRONGLY DIFFLUENT REGION OF THIS LOW HAVE BEEN COOLING RAPIDLY TONIGHT WITH TOPS TO -45C AT 08Z. LATEST OBS TO OUR NORTH SHOW SNOW ALONG THE EASTERN SLOPES OF THE CANADIAN ROCKIES FROM CALGARY TO EDSON. LATEST MODELS AND EVEN THE 07Z RAP SHOW THE JET NOSING TOWARD SOUTH CENTRAL MT BY THIS EVENING...LEAVING US IN A FAVORABLE POSITION FOR UPPER DIVERGENCE. ALL MODELS HAVE BEEN CONSISTENTLY SHOWING STRONG Q-VECTOR CONVERGENCE OVER OUR CWA TONIGHT THRU MUCH OF THURSDAY. ASCENT WILL NOT BE AN ISSUE WITH THIS SYSTEM...BUT AREA OF FRONTOGENESIS AND UPSLOPE FLOW WILL DICTATE WHERE THE HEAVIEST PCPN WILL BE. CONFIDENCE CONTINUES TO INCREASE FOR AN UPSLOPE EVENT MATERIALIZING BY THIS EVENING AND LASTING THROUGH MUCH OF THURSDAY. LATEST OBSERVATIONS TO OUR NORTH HELP TO GIVE CREDENCE TO THIS SCENARIO. IT ALSO SHOULD BE NOTED THAT MID LEVEL LAPSE RATES ON THE ORDER OF 6-7 C/KM OVER OUR WEST SUGGEST A CONVECTIVE COMPONENT OF THE PCPN TONIGHT THROUGH THURSDAY. PCPN CHANCES WILL BE INCREASING TODAY WITH ISENTROPIC ASCENT AND DIFFLUENCE ALOFT AND LATEST REGIONAL RADAR SHOWS SHOWERS SPREADING IN FROM THE NORTH. AREAS OF FOG/DRIZZLE ALSO EXIST PER THE LOW LEVEL SATURATED LAYER WITH UPSLOPE WINDS. TEMPS ACROSS OUR CWA WILL SUPPORT A CHILLY RAIN WITH THE EXCEPTION OF THE HIGH COUNTRY. BY 00Z...SECONDARY PUSH OF COLD ADVECTION WILL KICK IN SO EXPECT SNOW LEVELS TO FALL SIGNIFICANTLY BY THIS EVENING. HAVE ISSUED A WINTER WX ADVISORY FOR OUR NW PARTS...SPECIFICALLY FROM THE EAST SIDE OF THE CRAZY MTNS THROUGH JUDITH GAP...PER A PERIOD OF DEEP EAST FLOW AS THE UPPER TROF MOVES IN AND AN EXPECTED TRANSITION TO SNOW BY THIS EVENING. WOULD EXPECT THE BEARTOOTH AND RED LODGE FOOTHILLS TO SEE UPSLOPE SNOWFALL BEGINNING SOMETIME THIS EVENING ALSO. HAVE ISSUED A WINTER STORM WARNING FOR THE FOOTHILLS AND ALSO THE NORTH/EAST SLOPES OF THE BEARTOOTH...ABSAROKA AND CRAZY MTNS. FOR ALL OF THESE HIGHLIGHTS THE SNOW AMTS WILL VARY PER ELEVATION BUT THE BIGGEST IMPACT WILL BE THE POTENTIAL FOR DOWNED TREES AND POWER LINES. ANYONE PLANNING TRIPS TO THE HIGH COUNTRY WILL ALSO BE IMPACTED INCLUDING BEARTOOTH PASS. MODELS CONTINUE TO SUGGEST BETWEEN A HALF INCH AND INCH OF PCPN DURING TIME OF PEAK ASCENT...SO SEVERAL INCHES OF SNOWFALL COULD OCCUR IN THESE UPSLOPE AREAS. TURNING TO THE BIG HORNS AND SHERIDAN COUNTY...THOUGH THE MTNS WILL SEE A HEAVY SNOWFALL...TRANSITION TO SNOW WILL BE A BIT LATER FOR THE CITY OF SHERIDAN...PERHAPS LATE EVENING OR INTO THE OVERNIGHT HOURS. POTENTIAL STILL EXISTS FOR AN INCH OF WATER AND HEAVY SNOWFALL ON THE EASTERN ASPECTS OF THE BIG HORNS. GIVEN SOME UNCERTAINTY IN SFC TEMPS IN SHERIDAN WILL LET THE WATCH CONTINUE AND HAVE THE DAY SHIFT MAKE THE FINAL CALL ON SPECIFIC HIGHLIGHTS. OTHER LOCATIONS WHICH MAY BE IMPACTED INCLUDE THE HIGHER HILLS ACROSS OUR SOUTHEAST FROM SOUTHERN BIG HORN TO POWDER RIVER COUNTIES...SUCH PLACES AS THE WOLF MTNS AND LAME DEER DIVIDE. WOULD EXPECT SOME SLUSHY ACCUMULATION IN THESE AREAS TOO ESPECIALLY IF FRONTOGENESIS LINGERS A BIT NORTH OF THE FOOTHILLS AS SOME MODELS SUGGEST. SYSTEM WILL WIND DOWN THURSDAY AFTERNOON AND EVENING. TEMPS TODAY AND THURSDAY WILL MAX OUT ONLY IN THE 40S...WITH SOME RECORD COLD HIGH TEMPS BEING CHALLENGED. COLDEST NIGHT WILL BE THURSDAY NIGHT AS 1035MB SFC HIGH BUILDS IN AND ALLOWS FOR CLEARING AND STRONG RADIATIONAL COOLING. SOME RECORD LOWS ARE POSSIBLE THURSDAY NIGHT...AND SHERIDAN MAY SEE A LOW TEMP NEAR 20 DEGREES...A REMARKABLE NUMBER FOR SEPTEMBER 12TH. JKL .LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE... ONCE THE STORM SYSTEM EXITS THE AREA LATE THURSDAY...NORTHWESTERLY FLOW WILL REMAIN OVER THE AREA INTO THE WEEKEND. LATEST MODEL RUNS CONTINUE TO TREND DRIER WITH THE FORECAST FOR THE WEEKEND AS CLIPPER TYPE DISTURBANCES IN THE NORTHWEST STAY MAINLY NORTH OF THE AREA. THIS LEAVES A DRIER DOWNSLOPE REGIME IN PLACE FOR SOUTHERN MONTANA. TEMPERATURES WILL REMAIN BELOW AVERAGE THROUGH THE WEEKEND. BY EARLY NEXT WEEK FLOW ALOFT TURNS WESTERLY ALLOWING STRONGER DOWNSLOPE WARMING AND DRYING...WITH TEMPERATURES RESPONDING INTO THE 70S AND MAYBE EVEN LOWER 80S BY NEXT WEDNESDAY. WILL KEEP AN EYE ON CLIPPER SYSTEM PROGRESSION FOR ANY SIGNS OF A SOUTHWARD SHIFT THAT COULD BRING A PERIOD OF SHOWERS TO THE AREA THIS WEEKEND...BUT OVERALL LOOKS LIKE A VERY PLEASANT WEEKEND AHEAD AT THIS TIME. CHAMBERS && .AVIATION... IFR OR LOWER CONDITIONS WILL BE WIDESPREAD THIS MORNING...WITH OCCASIONAL MVFR CONDITIONS WHERE SHOWER ACTIVITY DISTURBS THE NEAR SURFACE STRATUS AND FOG. WARMING MID DAY SHOULD ALLOW CEILINGS AND VISIBILITY TO IMPROVE A BIT WITH MVFR CONDITIONS PREVAILING DURING THE AFTERNOON...THOUGH POCKETS OF IFR WILL PERSIST. IFR OR LOWER CONDITIONS WILL QUICKLY RE-DEVELOP EARLY THIS EVENING AS PRECIPITATION INCREASES WITH ARRIVAL OF MAIN STORM SYSTEM. MOUNTAIN TOPS WILL SEE PERIODIC CLEARING ESPECIALLY THIS AFTERNOON BUT PASSES WILL BE OBSCURED TODAY. CHAMBERS && .PRELIMINARY POINT TEMP/POPS... TDY THU FRI SAT SUN MON TUE ------------------------------------------------------- BIL 045 032/044 029/060 038/061 042/065 045/072 048/077 9/R 98/O 10/U 01/U 11/U 10/U 11/U LVM 047 030/044 024/060 032/062 034/069 040/074 044/081 6/R 97/O 10/U 01/U 11/U 10/U 01/U HDN 047 034/046 028/061 037/064 041/068 044/073 046/077 9/R 98/O 20/U 01/U 11/U 11/U 11/U MLS 047 034/049 031/061 038/063 041/066 044/070 047/077 9/R 64/O 20/U 01/U 11/U 11/U 01/U 4BQ 047 033/045 028/058 037/063 040/065 044/071 047/076 8/R 78/O 21/U 01/U 11/U 10/U 11/U BHK 046 033/047 029/055 035/064 038/065 041/070 044/074 7/R 44/O 21/U 01/U 11/U 11/U 01/U SHR 049 032/040 022/057 032/063 036/067 041/073 044/079 6/R ++/O 31/U 01/U 11/U 11/U 11/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WINTER WEATHER ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO NOON MDT THURSDAY FOR ZONES 28-41-63. WINTER STORM WARNING IN EFFECT FROM 6 PM THIS EVENING TO 3 PM MDT THURSDAY FOR ZONES 56-66-67. WINTER STORM WARNING IN EFFECT UNTIL 3 PM MDT THURSDAY FOR ZONE 68. WY...WINTER STORM WATCH IN EFFECT FROM 6 PM MDT THIS EVENING THROUGH THURSDAY MORNING FOR ZONES 98-99. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1137 AM EDT WED SEP 10 2014 .SYNOPSIS... LOW PRESSURE OVER IOWA WILL MOVE ACROSS LAKE HURON PULLING A STRONG COLD FRONT ACROSS THE AREA WEDNESDAY NIGHT. A WAVE OF LOW PRESSURE WILL MOVE UP THE OHIO VALLEY FRIDAY NIGHT INTO SATURDAY THEN HIGH PRESSURE OVER THE NORTHERN PLAINS WILL MOVE EAST THROUGH THE REGION SUNDAY AND MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATE...MADE MORE ADJUSTMENTS TO POPS AND WX BASED ON CURRENT RADAR TRENDS AND HRRR PROGS. ORIGINAL...THE QUESTION TODAY IS HOW FAR OUT AHEAD OF THE APPROACHING COLD FRONT WILL THE TSRA OCCUR. THE LATEST MODEL RUNS HAVE QPF RAPIDLY SPREADING ESE ACROSS THE CWA BETWEEN 18Z AND 00Z. WILL INCREASE POPS MORE FOR TODAY. THE THREAT FOR SEVERE STORMS STILL LOOKS GOOD BASED ON INSTABILITY AND FAIRLY GOOD WIND SHEAR. PW`S RISE BACK TO AROUND 2 INCHES SO LOCALLY HEAVY RAIN CAN BE EXPECTED. PATCHY MORNING FOG IN THE SOUTH WILL DISSIPATE THROUGH 10 AM. TODAY WILL BE THE LAST RELATIVELY WARM DAY FOR A WHILE...POSSIBLY THE REST OF THE SEASON BASED ON UPPER TROUGHING THAT IS GOING TO SET UP OVER THE LAKES FOR AT LEAST THE NEXT 10 DAYS. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... A FINAL BAND OF TSRA WITH THE STRONG COLD FRONT SHOULD PROGRESS ACROSS THE CWA BETWEEN 06Z AND 12Z SO AFTER 12Z THU ONLY THE SE HALF OF THE CWA SHOULD STILL HAVE A THREAT FOR RAIN WITH THE STRONGER CONVECTION THEN EXITING THE CWA. DRIER AIR MOVES IN BEHIND THE FRONT ALONG WITH THE LEADING PART OF A MUCH COOLER AIRMASS. MARGINAL LAKE EFFECT CONDITIONS START TO DEVELOP BY THE END OF THU NIGHT SO A FEW SHRA COULD BREAK OUT OVER THE SNOWBELT AND NEARBY AREAS. A SHARP S/W IS PROGGED TO MOVE EAST ACROSS THE LAKES FRI NIGHT INTO SAT AND INDUCE A SURFACE WAVE THAT MOVES UP THE OH VALLEY. MOISTURE POOLS BACK OVER THE AREA WITH WIDESPREAD SHRA DEVELOPING FRI NIGHT AND CONTINUING INTO SAT BEFORE SHIFTING INTO MAINLY THE EAST SAT AFTERNOON. HIGH PRESSURE IS SHOWN TO BE QUICKLY SPREADING OVER THE AREA BY SAT NIGHT BUT LAKE EFFECT CONDITIONS ARE POSSIBLE BASED ON TEMP DIFFERENCES. DUE TO WIND ISSUES AND SUBSIDENCE FROM THE HIGH WILL KEEP ONLY A SLIGHT CHANCE GOING SAT NIGHT IN THE NE. TEMPS WILL TREND COOLER FOR FRI AND SAT WITH HIGHS BOTH DAYS MOSTLY 60 TO 65 DEGREES. SOME SPOTS ON SAT MAY NOT EVEN GET TO 60 DEGREES IN THE INLAND EAST IF CLOUD COVER AND SHRA PERSIST. THE INCREASING CLOUDS FRI NIGHT SHOULD HOLD UP LOWS IN A 45 TO 50 RANGE BUT BY SAT NIGHT THE DECREASED CLOUDS AND LIGHT WINDS WILL ALLOW FOR LOWS IN THE LOW TO MID 40S. && .LONG TERM /SUNDAY THROUGH TUESDAY/... COOL HIGH PRESSURE WILL BE IN CONTROL OF THE REGION ON SUNDAY BUT IT WILL BE SHIFTING OFF TO THE EAST AS ANOTHER UPPER LEVEL TROUGH DIGS INTO THE GREAT LAKES REGION. AS THIS TROUGH MOVES OVERHEAD IT WILL BRING AN INCREASING CHANCE OF SHOWERS. THE BETTER CHANCES OF THE SHOWERS WILL BE MONDAY NIGHT INTO TUESDAY. THE SHOWERS MAY LINGER DOWNWIND OF LAKE ERIE INTO TUESDAY EVENING. THE NEXT AREA OF HIGH PRESSURE WILL THEN DRY THINGS OUT TUESDAY NIGHT INTO WEDNESDAY. IT WILL BE COOL THROUGH THE LONG TERM WITH TEMPERATURES BELOW SEASONAL AVERAGES. HIGHS AT MOST LOCATIONS WILL REMAIN IN THE 60S. HOWEVER BY TUESDAY AND WEDNESDAY THE WESTERN COUNTY WARNING AREA WILL BE NEAR TO SLIGHTLY ABOVE 70. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... SOME PATCHY MVFR FOG ACROSS THE EASTERN HALF OF THE REGION WILL BURN OFF QUICKLY. GUSTY SOUTHERLY WINDS WILL DEVELOP BY MID TO LATE MORNING AS A COLD FRONT MOVES TOWARD THE REGION. WIND GUSTS MAY REACH 30 TO 35 KNOTS NEAR THE LAKESHORE FROM CLEVELAND AND POINTS WEST FOR THE AFTERNOON AND EVENING. THE MAIN CONCERN WILL BE THE STRENGTH OF THE THUNDERSTORMS THAT DEVELOP THIS AFTERNOON/EVENING. HAVE MOVED UP THE TIMING OF THUNDERSTORMS TODAY WITH CURRENT RADAR TRENDS ALREADY SHOWING SHOWERS AND THUNDERSTORMS INTO CENTRAL INDIANA. THE FASTER TIMING COULD END UP BEING A GOOD THING SINCE THICKER CLOUD COVER WILL DECREASE THE INSTABILITY. THESE SHOWERS AND THUNDERSTORMS WILL THEN SLOWLY TRACK ACROSS THE REGION THROUGH THE OVERNIGHT. OUTLOOK...NON VFR POSSIBLE WEDNESDAY NIGHT INTO THURSDAY IN SHOWERS AND THUNDERSTORMS. LOWER CEILINGS MAY LINGER OVER NE OHIO AND NW PA INTO FRIDAY AND SATURDAY. && .MARINE... LOW PRESSURE WILL MOVE INTO THE CENTRAL GREAT LAKES TODAY WITH INCREASING SOUTH TO SOUTHWEST WINDS EXPECTED INTO THIS EVENING. WINDS WILL INCREASE THE EARLIEST ACROSS THE WESTERN BASIN WITH SOUTHERLY WINDS IN THE 15 TO 25 KNOT RANGE. WINDS WILL BE OFFSHORE SO WAVES SHOULD NOT BUILD ALL THAT MUCH. SINCE WINDS ARE EXPECTED TO BE IN THE 15 TO 25 KNOT RANGE WE HOISTED THE SMALL CRAFT ADVISORY FOR THIS AFTERNOON. WINDS WILL EVENTUALLY SHIFT AROUND TO THE WEST AND NORTHWEST IN THE WAKE OF THE COLD FRONT TONIGHT. THE FRONT SHOULD BE EAST OF THE LAKE BY 12Z THURSDAY. THE REMAINDER OF THE LAKE WILL NEED TO HAVE A SMALL CRAFT ADVISORY AT SOME POINT THIS EVENING INTO THE OVERNIGHT. LATER SHIFTS WILL ISSUE IT WHEN IT IS NEEDED. THE COLD ADVECTION IN THE WAKE OF THE FRONT WILL KEEP LARGER WAVES (4-6 FEET) GOING INTO AT LEAST THURSDAY AFTERNOON/EVENING. AS HIGH PRESSURE RIDGES OVER THE REGION WINDS WILL BECOME NORTHEAST BY FRIDAY MORNING. THIS WILL SET UP A LONG FETCH INTO THE WESTERN HALF OF THE LAKE. IF THE PRESSURE GRADIENT CAN REMAIN TIGHT ENOUGH WE MAY NEED SMALL CRAFT ADVISORIES AGAIN FRIDAY INTO SATURDAY. MORE DETAILS TO COME ON THIS SCENARIO THE NEXT COUPLE DAYS. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE FRONT AND TRACK ACROSS MUCH OF THE LAKE. A FEW OF THESE THUNDERSTORMS WILL BECOME STRONG ENOUGH TO WARRANT THE ISSUANCE OF SPECIAL MARINE WARNINGS FOR THIS EVENING AND POSSIBLY INTO THE OVERNIGHT. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EDT THURSDAY FOR LEZ142>145. && $$ SYNOPSIS...ADAMS NEAR TERM...ADAMS/TK SHORT TERM...ADAMS LONG TERM...MULLEN AVIATION...MULLEN MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
948 AM EDT WED SEP 10 2014 .SYNOPSIS... LOW PRESSURE OVER IOWA WILL MOVE ACROSS LAKE HURON PULLING A STRONG COLD FRONT ACROSS THE AREA WEDNESDAY NIGHT. A WAVE OF LOW PRESSURE WILL MOVE UP THE OHIO VALLEY FRIDAY NIGHT INTO SATURDAY THEN HIGH PRESSURE OVER THE NORTHERN PLAINS WILL MOVE EAST THROUGH THE REGION SUNDAY AND MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATE...MADE SOME ADJUSTMENTS TO POPS AND WX BASED ON CURRENT RADAR TRENDS AND HRRR PROGS. ORIGINAL...THE QUESTION TODAY IS HOW FAR OUT AHEAD OF THE APPROACHING COLD FRONT WILL THE TSRA OCCUR. THE LATEST MODEL RUNS HAVE QPF RAPIDLY SPREADING ESE ACROSS THE CWA BETWEEN 18Z AND 00Z. WILL INCREASE POPS MORE FOR TODAY. THE THREAT FOR SEVERE STORMS STILL LOOKS GOOD BASED ON INSTABILITY AND FAIRLY GOOD WIND SHEAR. PW`S RISE BACK TO AROUND 2 INCHES SO LOCALLY HEAVY RAIN CAN BE EXPECTED. PATCHY MORNING FOG IN THE SOUTH WILL DISSIPATE THROUGH 10 AM. TODAY WILL BE THE LAST RELATIVELY WARM DAY FOR A WHILE...POSSIBLY THE REST OF THE SEASON BASED ON UPPER TROUGHING THAT IS GOING TO SET UP OVER THE LAKES FOR AT LEAST THE NEXT 10 DAYS. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... A FINAL BAND OF TSRA WITH THE STRONG COLD FRONT SHOULD PROGRESS ACROSS THE CWA BETWEEN 06Z AND 12Z SO AFTER 12Z THU ONLY THE SE HALF OF THE CWA SHOULD STILL HAVE A THREAT FOR RAIN WITH THE STRONGER CONVECTION THEN EXITING THE CWA. DRIER AIR MOVES IN BEHIND THE FRONT ALONG WITH THE LEADING PART OF A MUCH COOLER AIRMASS. MARGINAL LAKE EFFECT CONDITIONS START TO DEVELOP BY THE END OF THU NIGHT SO A FEW SHRA COULD BREAK OUT OVER THE SNOWBELT AND NEARBY AREAS. A SHARP S/W IS PROGGED TO MOVE EAST ACROSS THE LAKES FRI NIGHT INTO SAT AND INDUCE A SURFACE WAVE THAT MOVES UP THE OH VALLEY. MOISTURE POOLS BACK OVER THE AREA WITH WIDESPREAD SHRA DEVELOPING FRI NIGHT AND CONTINUING INTO SAT BEFORE SHIFTING INTO MAINLY THE EAST SAT AFTERNOON. HIGH PRESSURE IS SHOWN TO BE QUICKLY SPREADING OVER THE AREA BY SAT NIGHT BUT LAKE EFFECT CONDITIONS ARE POSSIBLE BASED ON TEMP DIFFERENCES. DUE TO WIND ISSUES AND SUBSIDENCE FROM THE HIGH WILL KEEP ONLY A SLIGHT CHANCE GOING SAT NIGHT IN THE NE. TEMPS WILL TREND COOLER FOR FRI AND SAT WITH HIGHS BOTH DAYS MOSTLY 60 TO 65 DEGREES. SOME SPOTS ON SAT MAY NOT EVEN GET TO 60 DEGREES IN THE INLAND EAST IF CLOUD COVER AND SHRA PERSIST. THE INCREASING CLOUDS FRI NIGHT SHOULD HOLD UP LOWS IN A 45 TO 50 RANGE BUT BY SAT NIGHT THE DECREASED CLOUDS AND LIGHT WINDS WILL ALLOW FOR LOWS IN THE LOW TO MID 40S. && .LONG TERM /SUNDAY THROUGH TUESDAY/... COOL HIGH PRESSURE WILL BE IN CONTROL OF THE REGION ON SUNDAY BUT IT WILL BE SHIFTING OFF TO THE EAST AS ANOTHER UPPER LEVEL TROUGH DIGS INTO THE GREAT LAKES REGION. AS THIS TROUGH MOVES OVERHEAD IT WILL BRING AN INCREASING CHANCE OF SHOWERS. THE BETTER CHANCES OF THE SHOWERS WILL BE MONDAY NIGHT INTO TUESDAY. THE SHOWERS MAY LINGER DOWNWIND OF LAKE ERIE INTO TUESDAY EVENING. THE NEXT AREA OF HIGH PRESSURE WILL THEN DRY THINGS OUT TUESDAY NIGHT INTO WEDNESDAY. IT WILL BE COOL THROUGH THE LONG TERM WITH TEMPERATURES BELOW SEASONAL AVERAGES. HIGHS AT MOST LOCATIONS WILL REMAIN IN THE 60S. HOWEVER BY TUESDAY AND WEDNESDAY THE WESTERN COUNTY WARNING AREA WILL BE NEAR TO SLIGHTLY ABOVE 70. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... SOME PATCHY MVFR FOG ACROSS THE EASTERN HALF OF THE REGION WILL BURN OFF QUICKLY. GUSTY SOUTHERLY WINDS WILL DEVELOP BY MID TO LATE MORNING AS A COLD FRONT MOVES TOWARD THE REGION. WIND GUSTS MAY REACH 30 TO 35 KNOTS NEAR THE LAKESHORE FROM CLEVELAND AND POINTS WEST FOR THE AFTERNOON AND EVENING. THE MAIN CONCERN WILL BE THE STRENGTH OF THE THUNDERSTORMS THAT DEVELOP THIS AFTERNOON/EVENING. HAVE MOVED UP THE TIMING OF THUNDERSTORMS TODAY WITH CURRENT RADAR TRENDS ALREADY SHOWING SHOWERS AND THUNDERSTORMS INTO CENTRAL INDIANA. THE FASTER TIMING COULD END UP BEING A GOOD THING SINCE THICKER CLOUD COVER WILL DECREASE THE INSTABILITY. THESE SHOWERS AND THUNDERSTORMS WILL THEN SLOWLY TRACK ACROSS THE REGION THROUGH THE OVERNIGHT. OUTLOOK...NON VFR POSSIBLE WEDNESDAY NIGHT INTO THURSDAY IN SHOWERS AND THUNDERSTORMS. LOWER CEILINGS MAY LINGER OVER NE OHIO AND NW PA INTO FRIDAY AND SATURDAY. && .MARINE... LOW PRESSURE WILL MOVE INTO THE CENTRAL GREAT LAKES TODAY WITH INCREASING SOUTH TO SOUTHWEST WINDS EXPECTED INTO THIS EVENING. WINDS WILL INCREASE THE EARLIEST ACROSS THE WESTERN BASIN WITH SOUTHERLY WINDS IN THE 15 TO 25 KNOT RANGE. WINDS WILL BE OFFSHORE SO WAVES SHOULD NOT BUILD ALL THAT MUCH. SINCE WINDS ARE EXPECTED TO BE IN THE 15 TO 25 KNOT RANGE WE HOISTED THE SMALL CRAFT ADVISORY FOR THIS AFTERNOON. WINDS WILL EVENTUALLY SHIFT AROUND TO THE WEST AND NORTHWEST IN THE WAKE OF THE COLD FRONT TONIGHT. THE FRONT SHOULD BE EAST OF THE LAKE BY 12Z THURSDAY. THE REMAINDER OF THE LAKE WILL NEED TO HAVE A SMALL CRAFT ADVISORY AT SOME POINT THIS EVENING INTO THE OVERNIGHT. LATER SHIFTS WILL ISSUE IT WHEN IT IS NEEDED. THE COLD ADVECTION IN THE WAKE OF THE FRONT WILL KEEP LARGER WAVES (4-6 FEET) GOING INTO AT LEAST THURSDAY AFTERNOON/EVENING. AS HIGH PRESSURE RIDGES OVER THE REGION WINDS WILL BECOME NORTHEAST BY FRIDAY MORNING. THIS WILL SET UP A LONG FETCH INTO THE WESTERN HALF OF THE LAKE. IF THE PRESSURE GRADIENT CAN REMAIN TIGHT ENOUGH WE MAY NEED SMALL CRAFT ADVISORIES AGAIN FRIDAY INTO SATURDAY. MORE DETAILS TO COME ON THIS SCENARIO THE NEXT COUPLE DAYS. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE FRONT AND TRACK ACROSS MUCH OF THE LAKE. A FEW OF THESE THUNDERSTORMS WILL BECOME STRONG ENOUGH TO WARRANT THE ISSUANCE OF SPECIAL MARINE WARNINGS FOR THIS EVENING AND POSSIBLY INTO THE OVERNIGHT. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EDT THURSDAY FOR LEZ142>145. && $$ SYNOPSIS...ADAMS NEAR TERM...ADAMS/TK SHORT TERM...ADAMS LONG TERM...MULLEN AVIATION...MULLEN MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1122 AM EDT WED SEP 10 2014 .SYNOPSIS... LOW PRESSURE OVER THE MIDDLE PART OF THE COUNTRY WILL STRENGTHEN AS IT MOVES INTO THE GREAT LAKES TODAY. THE TRAILING COLD FRONT WILL MOVE EAST INTO THE OHIO AND TENNESSEE VALLEYS TONIGHT AND THURSDAY...THEN CROSS THE MOUNTAINS THURSDAY NIGHT. THE FRONT IS EXPECTED TO STALL OVER THE CAROLINAS FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1113 AM EDT WEDNESDAY... UPDATING TO LOWER TEMPS A BIT AND HOLD CLOUDS LONGER ESPCLY ALONG THE BLUE RIDGE WHERE LOW CLOUDS REMAIN PERSISTENT WITH EVEN SOME SPOTTY -RA MIXED IN GIVEN THE WEAK LOW LEVEL VEERING PROFILE OFF MORNING RAOBS. ALSO WITH SO MUCH LINGERING MOISTURE STUCK BENEATH MULTIPLE INVERSIONS ALOFT OFF 12Z SOUNDINGS APPEARS WILL BE TOUGH TO GET A QUICK EROSION OF THE CANOPY WITHOUT IT FILLING BACK IN ESPCLY EARLY ON. EXPECT ONCE THE FLOW TURNS MORE SOUTH/SW LATER ON AND MIXING INCREASES WILL SEE SOME DRIER AIR ALOFT MIX DOWN BUT MAY BE LATE BEFORE THE EASTERN SLOPES OF THE BLUE RIDGE SEE A LOT OF SUN. TEMPS LIKELY TO JUMP WHERE DO GET SOME SUSTAINED BREAKS BUT FOR NOW BASED ON LATEST TRENDS AND LAV MOS...THINK HIGHS MAY REMAIN IN THE 70S EXCEPT FOR THE FAR EAST/SE AND WESTERN PERIMETER COUNTIES. ISOLATED WESTERN POPS THIS AFTERNOON STILL APPEAR OK WITH THE BRIEF SHOTGUN PATTERN SUGGESTED BY THE LATEST HRRR BUT THIS BASED ON SOME INSTABILITY PER HEATING WHICH MAY ONLY OCCUR ALONG THE I-77 CORRIDOR AT THIS POINT. PREVIOUS UPDATE AS OF 925 AM EDT WEDNESDAY... ADDED SLIGHT CHANCE POPS ALONG THE BLUE RIDGE UP TO ROANOKE AS SURFACE OBS AND WEATHER SPOTTERS HAVE CONFIRMED SOME LIGHT DRIZZLE THIS MORNING. TWEAKED THE SKY GRIDS OUT WEST WHERE THERE HAS BEEN SOME CLEARING. ALSO ADJUSTED THE NEAR TERM TEMPS. ALL OTHER FORECAST DETAILS FROM THE PREVIOUS DISCUSSION REMAIN ON TRACK. PREVIOUS DISCUSSION AS OF 430 AM EDT WEDNESDAY... STARTING OFF WITH LOTS OF CLOUD COVER THIS MORNING...COURTESY OF LINGERING MOISTURE BANKED UP AGAINST THE EAST SIDE OF THE MOUNTAINS. THE EASTERLY WIND WHICH HAS BEEN KEEPING THE CLOUDS PINNED ACROSS THE AREA WILL WEAKEN TODAY AS FLOW BEGINS TO TREND MORE SOUTHERLY PER APPROACH OF FRONTAL SYSTEM OVER THE MIDDLE PART OF THE COUNTRY. AS OF 4AM...CYCLOGENESIS WAS TAKING PLACE OVER THE MIDDLE PART OF THE COUNTRY WITH LOW PRESSURE DEVELOPING NEAR TOPEKA KANSAS. THIS AREA OF LOW PRESSURE IS FORECAST TO STRENGTHEN TODAY PER STRONG DYNAMICS ALOFT ASSOCIATED WITH A SHORT WAVE TROUGH EXITING THE ROCKIES. THE DEEPENING LOW...10 MB PRESSURE FALL OVER THE NXT 12 HOURS...IS PROGGED TO MOVE NORTHEAST INTO THE GREAT LAKES...THE TRAILING COLD FRONT SLICING SOUTH THROUGH MISSOURI-TEXAS. AHEAD OF THE FRONT...WINDS WILL BE SOUTHWESTERLY THROUGH THE TENNESSEE AND OHIO VALLEYS...WARM AIR ADVECTION TAKING PLACE UPSTREAM OF OUR FORECAST AREA...AND EVENTUALLY INCLUDING OUR FORECAST AREA LATER TODAY AND TONIGHT. AS WARM AIR ADVECTION INCREASES FROM THE SOUTHWEST LATER TODAY...EXPECT CLOUD COVER CURRENTLY OVER OUR FORECAST AREA TO MIX OUT WITH INCREASING AMOUNTS OF SUN. SUNNY BREAKS WILL LIKELY BEGIN IN THE WESTERN PART OF THE CWA FIRST...THEN SPREAD EAST. MORE SUN MEANS WARMER TEMPERATURES...MODEL MOS SUGGESTING WE TEST 80 TODAY WITH A TEMPERATURE RANGE OF 76 TO 83. MILD TEMPERATURES ARE LIKELY TONIGHT...SOUTHWEST WINDS CONTINUING TO PROMOTE WARM AIR ADVECTION...LOWS IN THE 60S. NOT MUCH THREAT FOR PRECIP TODAY OR TONIGHT. MODEL SOUNDINGS INDICATE CAPE VALUES POTENTIALLY REACHING 500 J/KG IN THE MOUNTAINS TODAY. THIS MAY SUPPORT AN ISOLATED SHOWER OR TWO...BUT NOT MUCH MORE THAN THAT. BETTER CHANCE FOR PRECIP WILL COME WITH THE FRONTAL PASSAGE LATER THURSDAY. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... AS OF 400 AM EDT WEDNESDAY... LOOK FOR THURSDAY TO BE THE WARMEST DAY OF THE WEEK AS DEEP SOUTHWESTERLY FLOW BECOMES ESTABLISHED AHEAD OF A STRONG COLD FRONT APPROACHING FROM THE GREAT LAKES REGION. THE SOUTHWESTERLY WINDS WILL DRAW VERY WARM GULF MOISTURE NORTHWARD ALONG THE APPALACHIAN CHAIN...WHICH WILL HELP AFTERNOON HIGHS CLIMB INTO THE UPPER 70S/LOW 80S ACROSS THE MOUNTAINS...WHILE THE PIEDMONT WILL REACH INTO THE MID 80S TO AROUND 90 IN THE SOUTHSIDE. RAIN CHANCES WILL INCREASE DRASTICALLY DURING THE AFTERNOON AS THE FRONT CROSSES THE OHIO RIVER...WITH SHOWERS AND THUNDERSTORMS BECOMING WIDESPREAD ACROSS MOST OF THE AREA BY SUNSET. STORM PREDICTION CENTER HAS MUCH OF OUR FORECAST REGION UNDER A SLIGHT CHANCE FOR SEVERE THUNDERSTORMS...SO WILL BE ON THE LOOKOUT FOR A FEW STORMS PACKING GUSTY WINDS DURING THE EVENING...MAINLY NORTH OF HIGHWAY 460...AS THE STRONGER DOWNDRAFTS TRY TO PULL THE 25KT-30KT 850MB WINDS DOWN TO THE SURFACE. BELIEVE THERE WILL ALSO BE A CHANCE FOR LOCALLY HEAVY RAIN ACROSS THE MOUNTAINS AS GULF MOISTURE POOLING AHEAD OF THE FRONT PUSHES PRECIPITABLE WATER IN THE BALLPARK OF 2 INCHES. THE COLD FRONT WILL CONTINUE ITS SOUTHWARD PUSH THURSDAY NIGHT... BEFORE STALLING ACROSS CENTRAL NORTH CAROLINA JUST SOUTH OF OUR AREA ON FRIDAY AS IT RUNS INTO UPPER LEVEL RIDGING ACROSS THE SOUTHEAST STATES. MODELS ARE COMING INTO BETTER AGREEMENT THAT...DESPITE THE FRONTAL PASSAGE...DEWPOINTS DO NOT DROP OFF ALL THAT MUCH FOR OUR AREA. AS SUCH...EXPECT THAT THERE WILL BE ENOUGH LOW LEVEL MOISTURE LEFT OVER TO SUPPORT SCATTERED SHOWER ACTIVITY ACROSS THE MOUNTAINS AND THE PIEDMONT SOUTH OF HIGHWAY 460 THROUGH THE AFTERNOON AND EVENING. DRIER HIGH PRESSURE WILL BE WEDGING SOUTHWARD ACROSS THE PIEDMONT FURTHER NORTH. HIGHS FOR FRIDAY WILL BE COOLER...MAINLY IN THE 70S MOST LOCATIONS. SHOWER ACTIVITY WILL INCREASE AGAIN ON SATURDAY AS A WAVE OF LOW PRESSURE DEVELOPS ALONG THE FRONT. SURFACE HIGH PRESSURE BANKED AGAINST THE EASTERN FACE OF THE APPALACHIANS WILL PROVIDE ENOUGH STABILITY TO LIMIT RAINFALL TO SHOWER ACTIVITY FOR MOST OF THE AREA...ALTHOUGH AN ISOLATED THUNDERSTORM MAY DEVELOP ACROSS THE MOUNTAIN EMPIRE...AN AREA REMOVED FROM THE INFLUENCE OF THE HIGH. AT ANY RATE...THE WAVE WILL SHIFT RAPIDLY TO THE NORTH ON SATURDAY... DRAGGING A SECONDARY COLD FRONT ACROSS OUR AREA DURING THE EVENING. CANADIAN HIGH PRESSURE BUILDING IN BEHIND THE COLD FRONT WILL BE THE COOLEST AIR WE HAVE SEEN IN SEVERAL MONTHS...A DEFINITE SIGNAL THAT AUTUMN IS NOT TOO FAR INTO THE FUTURE. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 100 PM EDT TUESDAY... FORECAST REMAINS RATHER LOW CONFIDENCE FOR SUNDAY INTO TUESDAY GIVEN WEST/SW FLOW ALOFT BETWEEN AN UPPER TROUGH TO THE NW AND THE RESIDUAL AXIS OF DEEPER MOISTURE ALONG THE COAST. LATEST GUIDANCE STILL RATHER MIXED ON DEGREE OF MOISTURE GETTING PULLED BACK INLAND/NORTH AHEAD OF THE MAIN TROUGH AS APPEARS SOME SORT OF LEFTOVER DEFORMATION AXIS MAY LINGER WITH THE COASTAL LOW. THUS KEPT SOME LOW POPS IN SOUTH/EAST ESPCLY SUNDAY/SUNDAY NIGHT THEN DECREASING MONDAY FOR NOW. APPEARS DRIER AIR WITH THE STRONGER SURFACE HIGH BUILDING IN FROM THE NW WILL FINALLY OCCUR BY TUESDAY BUT EVEN THEN CLOUDS/SHOWERS MAY LINGER/RETURN WITH YET ANOTHER WAVE PASSING. TEMPS TO COOL BELOW NORMAL THROUGH THE PERIOD WITH MAINLY 60S MOUNTAINS AND LOW 70S EAST FOR HIGHS...AND 50S WEST 60S PIEDMONT FOR LOWS PENDING CLOUD COVER WHICH COULD MAKE HIGHS EVEN COOLER. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... AS OF 800 AM EDT WEDNESDAY... STUBBORN LOW LEVEL CLOUDS WILL LIKELY REMAIN THROUGH THE MORNING...MVFR CONDITIONS PERSISTING THROUGH NOON BEFORE LIFTING INTO THE VFR CATEGORY FOR THE AFTERNOON. WINDS TODAY ARE EXPECTED TO BECOME SOUTHERLY...PROMOTING THE BREAK UP OF THE EXISTING CLOUD COVER WHICH HAS BEEN BANKED UP AGAINST THE EAST SIDE OF THE APPALACHIANS THE LAST SEVERAL DAYS. A STRONG LOW PRESSURE SYSTEM WILL MOVE INTO THE GREAT LAKES TODAY IMPACTING AVIATION ROUTES THROUGH DTX-ORD-MSP. A TRAILING COLD FRONT WILL CROSS STL THIS AFTERNOON...THEN MOVE EAST INTO THE OHIO AND TN VALLEYS TONIGHT. SCATTERED TO NUMEROUS SHOWERS/STORMS WILL BE FOUND ALONG THE FRONT...WITH SEVERE STORMS POSSIBLE FROM DTX- STL. THIS UNSETTLED WEATHER ACTIVITY IS NOT EXPECTED TO REACH THE MID ATLANTIC REGION UNTIL LATER THURSDAY. UNTIL THEN...FROM THIS AFTERNOON THROUGH MID DAY THURSDAY...MAINLY VFR CONDITIONS WILL EXIST. CAN`T RULE OUT A BRIEF PERIOD OF FOG LATE TONIGHT AND EARLY THURSDAY...BUT IT SHOULD BE PATCHY AND CONFINED MAINLY TO THE RIVER VALLEYS. EXTENDED DISCUSSION... COLD FRONT WILL BRING THREAT OF SHOWERS AND STORMS TO THE AREA LATE THURSDAY AND THURSDAY NIGHT. FROPA IS EXPECTED THURSDAY NIGHT. THIS FRONTAL PASSAGE WILL NOT BE A CLEAN SWEEP OF AIRMASSES...THE MAJORITY OF THE MODELS INDICATING THE FRONT WILL STALL OVER THE CAROLINAS FRIDAY...FOLLOWED BY DEVELOPMENT OF LOW PRESSURE ALONG THE FRONT FRIDAY NIGHT...TRACKING NORTHEAST THROUGH THE REGION SATURDAY. CONFIDENCE IS BEGINNING TO INCREASE THAT AN EXTENDED PERIOD OF MVFR...POSSIBLY IFR...WILL EXIST FRIDAY NIGHT INTO SATURDAY. LOW CONFIDENCE FORECAST FOR SUNDAY. HALF THE MODELS BLOW THE SYSTEM OFF THE COAST CLEARING US FROM THE WEST SUNDAY. OTHER MODEL SOLUTIONS HANG ON TO THE LOWER LEVEL CLOUDINESS PER DEVELOPMENT OF LOW LEVEL EASTERLY WINDS OFF THE ATLANTIC...SIMILAR TO WHAT TRANSPIRED THE FIRST HALF OF THIS WEEK. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PM NEAR TERM...CF/JH/PM SHORT TERM...NF LONG TERM...JH AVIATION...PM
AREA FORECAST DISCUSSION
NWS TUCSON AZ
920 AM MST WED SEP 10 2014 .SYNOPSIS...MAINLY DRY CONDITIONS WILL OCCUR THROUGH THURSDAY. EXPECT ISOLATED TO SCATTERED AFTERNOON AND EVENING THUNDERSTORMS TO RETURN BY THIS WEEKEND AS MOISTURE INCREASES ACROSS THE AREA. A WARMING TREND WILL PREVAIL THROUGH FRIDAY FOLLOWED BY MODEST COOLING EARLY THIS WEEKEND. && .DISCUSSION...A NARROW BAND OF CLOUDINESS EXTENDED FROM THE WHITE MOUNTAINS SWWD INTO WRN PIMA COUNTY AT THIS TIME. A FEW SHOWERS PRODUCING MOSTLY SPRINKLES CONTINUED ACROSS FAR WRN PIMA COUNTY. OTHERWISE...SUNNY SKIES OR MOSTLY SUNNY SKIES PREVAILED ACROSS SE AZ. DEWPOINTS AT LOWER ELEVATIONS VALID 16Z WERE GENERALLY IN THE MID-UPPER 50S F. THESE TEMPS WERE ABOUT 5-10 DEGS F LOWER VERSUS 24 HOURS AGO. SURFACE TEMPS VALID 16Z WERE NEARLY IDENTICAL TO THIS TIME TUE. BLENDED TOTAL PRECIP WATER IMAGERY VALID 1357Z DEPICTED VALUES RANGING FROM AROUND THREE QUARTERS OF AN INCH ACROSS THE WHITE MOUNTAINS TO 1.20 INCHES ACROSS WRN PIMA COUNTY. THE BEST CHANCE FOR MEASURABLE PRECIP INTO THIS EVENING WILL BE ACROSS THE WHITE MOUNTAINS AS PER THE 10/12Z NAM/GFS...THE 10/12Z UNIV OF AZ WRF-NAM...AND THE 10/14Z RUC HRRR. HAVE OPTED TO REDUCE POPS ACROSS THE WHITE MOUNTAINS...BUT HAVE MAINTAINED A SLIGHT CHANCE OF SHOWERS THERE INTO THIS EVENING. HAVE ALSO MAINTAINED A SLIGHT CHANCE OF SHOWERS ACROSS FAR WRN PIMA COUNTY INTO THIS AFTERNOON. DRY CONDITIONS WILL PREVAIL ELSEWHERE THRU TONIGHT. HIGH TEMPS THIS AFTERNOON ARE FORECAST TO BE JUST A COUPLE OF DEGS OR SO WARMER VERSUS TUE. PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL. && .AVIATION...VALID THRU 11/18Z. ISOLATED -SHRA ACROSS FAR WRN PIMA COUNTY WEST OF KTUS AND ACROSS THE WHITE MOUNTAINS NE OF KSAD INTO THIS EVENING. OTHERWISE...EXPECT A FEW TO OCCASIONALLY BKN CLOUDS AT 8-12K FT AGL AND SURFACE WIND TO BE LESS THAN 10 KTS INTO THURSDAY MORNING. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...THERE IS A SLIGHT CHANCE OF AFTERNOON SHOWERS MAINLY ACROSS THE WHITE MOUNTAINS THROUGH THURSDAY. ISOLATED TO SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL THEN RETURN STARTING FRIDAY AND CONTINUE INTO EARLY NEXT WEEK AS MOISTURE INCREASES ACROSS THE AREA. OTHERWISE...20-FOOT WINDS WILL GENERALLY BE LIGHT AND TERRAIN DRIVEN...EXCEPT FOR STRONG GUSTY OUTFLOWS ASSOCIATED WITH THUNDERSTORMS. && .PREV DISCUSSION...MINIMAL SHOWERS AND THUNDERSTORMS EXPECTED AGAIN ON THURSDAY AND AGAIN MOSTLY FOR THE MOUNTAINS AND AREAS ALONG THE NEW MEXICO BORDER. BY FRIDAY HIGH PRESSURE OVER THE CENTRAL GULF COAST AND EXTENDING WEST ALONG THE SOUTHERN TIER OF STATES WILL RESULT IN A SOUTHEAST FETCH ON THE SOUTHERN FLANK OF THE RIDGE...WHICH WILL HELP TO USHER IN ADDITIONAL MOISTURE FOR A INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS. EVEN SO...ONLY LOOKING AT ISOLATED SHOWERS AND THUNDERSTORMS FOR CENTRAL ZONES...SUCH AS TUCSON...WITH SCATTERED ACTIVITY FOR AREAS SOUTH AND EAST OF TUCSON. THIS SET UP WILL GENERALLY CONTINUE THROUGH THE WEEKEND THROUGH EARLY NEXT WEEK. ANOTHER TROPICAL SYSTEM IS PROGGED TO REACH THE SOUTHERN TIP OF THE BAJA PENINSULA BY LATE SUNDAY/EARLY MONDAY...BUT IT IS TOO EARLY TO HANG OUR HATS ON ONE PARTICULAR SOLUTION...OR TO TRY AND COMPARE THIS NEXT SYSTEM WITH WHAT OCCURRED WITH NORBERT. THEREFORE...STAY TUNED FOR CONTINUOUSLY UPDATED AND REVISED FORECASTS BETWEEN NOW AND EARLY NEXT WEEK. HIGH TEMPERATURES WILL GENERALLY RANGE FROM 1 TO 3 DEGS BELOW NORMAL TODAY...THEN 1 TO 3 DEGS ABOVE NORMAL FOR THURSDAY AND FRIDAY. THEREAFTER...HIGHS HOVERING NEAR NORMAL. LOWS WILL BE NEAR TO SLIGHTLY ABOVE NORMAL THURSDAY MORNING...THEN 4 TO 6 DEGS ABOVE NORMAL EACH MORNING THEREAFTER. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON FRANCIS PREVIOUS DISCUSSION...MOLLERE
AREA FORECAST DISCUSSION
NWS PADUCAH KY
323 PM CDT Wed Sep 10 2014 .SHORT TERM...(Tonight through Friday night) Issued at 323 PM CDT WED SEP 10 2014 The showers are still trying to dissipate over southern Illinois, and now a tiny heavy shower has develop near KSAR in the last scan or two. The latest HRRR indicates that there may be some heavier convective elements with this pesky band of showers, as it moves eastward toward the EVV Tri State late this afternoon. Widespread cloud cover has stunted surface-based instability today, and this may help keep the severe weather threat in check as we move into this evening. Model soundings from southern Illinois and southwest Indiana reveal very weak lapse rates, and overall instability. There is decent low-level shear, possibly enough to support a few rotating updrafts. The low-level shear will weaken through the evening, and there is little shear above 3 km. Cannot rule out a stray severe thunderstorm, especially if it can display supercellular characteristics. Damaging winds still appear to be the primary concern, but large hail and a brief tornado cannot be ruled out. Precipitable water values are well above 2 inches, and this could lead to some torrential rainfall. Generally followed HPC QPF through Thursday, and this yields 1.5-2" over much of the area, with the possible exception of the far southeast corner of the forecast area. 1-hour and 3-hour Flash flood Guidance is well over 2", so will not be issuing a Flash Flood Watch at this time. Some nuisance flooding in low-lying and poorly draining areas is possible, but major problems are not expected. The heaviest rains will be waning over the southern half of the area toward sunrise. Still not sure when/where convective initiation will occur, but the latest HRRR runs have been consistent and developing scattered convection across northern portions of southeast Missouri into southern Illinois by 00Z. Convection currently developing along the cold front from west central Illinois into central Missouri is moving east and should not pose any immediate concern for our region, but figure that the convection will fill in between it and our scattered convection through the evening. Will keep some decent PoPs in the southeast Thursday morning, but it should be drying out over most areas in the afternoon. Thursday night and Friday morning should be dry, but as the next rather sharp upper-level storm system rotates eastward out of the central/northern Plains, would not be surprised to see some showers develop, as moisture is drawn back northward over the shallow Canadian airmass. This would primarily be in the south Friday afternoon, and then throughout the area Friday night. Still don`t think there will be much precipitation, but a slight chance of showers seems reasonable for both periods. As for temperatures, stayed close to the consensus of all guidance for lows tonight with the frontal passage. With clouds, precipitation and cool advection, went under guidance in the southeast Thursday. Went near consensus for lows Thursday night, and then went below guidance Friday and near or just above it Friday night. .LONG TERM...(Saturday through Wednesday) Issued at 323 PM CDT WED SEP 10 2014 Surface high pressure will build into the area on Saturday, providing much drier air and lowering temperatures. The center of the high will pass over the Great Lakes region and then move into the New England states. Our region should remain dry through the weekend though as weak high pressure continues to stay situated over us. Models try and bring a front into the area on Monday. The front weakens substantially as it arrives Monday into Monday night, so chances for precipitation appear minimal at this time but cloud cover should increase. Most of the upper level dynamics and moisture look to be to the north of our area. However, we will have to watch Monday night, as a few of the GFS ensemble members and the 12Z Euro are hinting that this front could produce some light precipitation, especially in our northwestern counties. Even the operational GFS indicates lower level moisture increasing by Monday night. For Tuesday, models differ on the degree of dry air filtering into the area, in association with the area of high pressure that moves toward us. The 12Z GFS is much more robust in scouring out the moisture while the 00Z ECMWF seems to keep plenty of moisture lingering until Wednesday. The 12Z run of the ECMWF is a bit more pronounced with drying us out now but still not as much as the GFS. Nevertheless, it looks like we`ll be dry on Tuesday. On Wednesday, the GFS starts to bring better moisture back into the area from the west and even hints at possible precipitation chances out in SEMO as well. However, the 12Z run was the only run that was this quick in bringing precipitation back in and even the 12Z ECMWF was dry. Temperatures will be coolest on Saturday and remain in the 70s for the majority of the extended period. There might be a few places that reach in the lower 80s by next week. Lows will generally be in the 50s but some upper 40s might be attainable on Saturday night especially in the north. && .AVIATION... Issued at 1248 PM CDT WED SEP 10 2014 MVFR ceilings should lift to VFR levels in the next hour or two at KEVV and KOWB. The band of showers that has been slowly moving toward the area this morning, is weakening as expected, and should have no impact on the terminals this afternoon. South southwest winds will gust well over 20kts at times this afternoon at all sites. Extensive cloud cover playing havoc with the destabilization process, so the timing and location of convective initiation is questionable. Given the forcing expected tonight, will keep general onset from previous forecast. There could be several hours of TS at all sites this evening into the early morning hours. The cold front will pass the terminals late tonight, and IFR or LIFR ceilings are a good bet behind the front. MVFR showers are also likely through at least sunrise behind the front. Not sure how much the ceilings will be able to lift/break up by 18Z Thursday. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...LAKE WIND ADVISORY until 6 PM CDT this evening FOR ILZ075>078- 080>094. MO...LAKE WIND ADVISORY until 6 PM CDT this evening FOR MOZ076-086- 087-100-107>112-114. IN...LAKE WIND ADVISORY until 6 PM CDT this evening FOR INZ081-082- 085>088. KY...LAKE WIND ADVISORY until 6 PM CDT this evening FOR KYZ001>022. && $$ SHORT TERM...DRS LONG TERM...CW AVIATION...DRS
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
308 PM CDT WED SEP 10 2014 .SHORT TERM... RATHER MOIST AIR MASS IN PLACE ON STEADY-STATE ONSHORE FLOW AROUND PERIPHERY OF BERMUDA RIDGE. MID LEVELS HAVE WARMED TO LIMIT THE DEPTH OF CONVECTIVE COVERAGE THROUGH AT LEAST 89F CONVECTIVE TEMPERATURES...OVERCOMING 500 MB WARM LAYER AROUND 91F SURFACE TEMPERATURE. RESULT WILL BE SHORT-LIVED SLOW-MOVING BUT EFFICIENT SHOWERS AND BRIEF THUNDERSTORMS FORMING MAINLY ON OUTFLOW INTERSECTIONS THAT ARE PROMINENTLY DISPLAYED ON RADAR PRESENTATION. THIS CONVECTION SHOULD DISSIPATE SHORTLY AFTER SUNSET. MEANWHILE...EASTERLY WAVE CURRENTLY TRAVERSING THE NORTHEAST GULF UNDER THE RIDGE WILL SERVE AS A FOCUS FOR DEEPER LOW LEVEL MOISTURE THURSDAY AND FRIDAY. THIS IS CONSISTENT WITH THE WRF AND HRRR MODEL RUNS FOR THURSDAY AFTERNOON AS WELL AS THE OTHER LONGER RANGE MODELS. WILL INDICATE HIGHER RAIN CHANCES CLOSER TO THE COAST AND TAPER DOWNWARD FARTHER INLAND THURSDAY. WITH FRONTAL ZONE SETTLING INTO THE AREA FRIDAY...WILL BE DIFFICULT TO DISTINGUISH FAVORED AREAS FOR FOCUSED RAINFALL DUE TO VARIOUS CAUSES/PROCESSES...SO WILL SIMPLY GO 50 PERCENT ENTIRE AREA. IF DEEPER GULF MOISTURE ALIGNS IN CONVERGENT BANDS...THEN SOME LOCATIONS MAY UNDERGO SOME SHORT DURATION OF TRAINING WHICH MAY ACCUMULATE MORE RAINFALL...MOSTLY LIKELY CLOSER TO THE COAST THOUGH FRONTAL ZONE MAY COMPLICATE MATTERS. .LONG TERM... MODELS ALL AGREE IN STALLING THE FRONT ALONG OR CLOSE TO THE GULF COAST SATURDAY AS UPPER SUPPORT SHUNTS EASTWARD. THIS DIFFERS FROM MAN-MACHINE MIX THAT CONTINUES TO INDICATE A DEEPER FRONTAL ADVANCE WELL INTO THE GULF BEFORE STALLING. ASSOCIATED CONVECTION AND OUTFLOWS MAY INDUCE THE SURFACE FRONT SOUTHWARD BUT THE AIR MASS WOULD BE GREATLY MODIFIED AND RUNNING MOSTLY ON RAIN COOLED DENSITY. IN COORDINATION WITH SURROUNDING OFFICES...WE WILL BE INDICATING WARMER THAN GUIDANCE TEMPERATURES FOR MORNING LOWS SUNDAY AND MONDAY IN DEFERENCE TO NATIONAL GUIDANCE...PARTICULARLY IF TROPICAL WAVE INFLUENCES BECOME INVOLVED THIS FAR SOUTH. WHILE ON THE SUBJECT...THE NHC HAS HIGHLIGHTED A YELLOW OUTLOOK AREA FROM THE BAHAMAS WESTWARD ACROSS THE NORTH GULF. THIS IS A TROPICAL WAVE THAT SHOULD REMAIN OPEN WHILE TRAVERSING UNDER THE UPPER RIDGE. SEVERAL MODELS INDICATE SUCH A SCENARIO...ONLY THE CANADIAN RUN SHOWS A CLOSED LOW STRUCTURE THAT DOES NOT LOOK ATTAINABLE GIVEN CURRENT PATTERN IN PLACE. NONETHELESS...THIS FEATURE SHOULD SERVE TO BRING GREATER FOCUS FOR RAINFALL POTENTIAL OVER THE WEEKEND...PARTICULARLY AS IT INTERACTS WITH ANY STATIONARY FRONTAL FOCUS. RAINFALL POTENTIAL CAN BECOME PRONOUNCED AND OF CONSIDERABLY LONG DURATION WHEREVER THE FRONT AND WAVE INTERSECT. THE KEY IS WHETER IT WILL BE OFF THE COAST OR JUST INLAND ENOUGH TO PRESENT A FLOOD THREAT FOR SOME COASTAL COMMUNITIES. THIS WILL HAVE TO BE CLOSELY MONITORED OVER THE NEXT FEW DAYS. && .AVIATION... VFR CONDITIONS TO PREVAIL THROUGH AT LEAST 09Z. SOME PATCHY RADIATIONAL FOG MAY DEVELOP AT KMCB TOWARDS DAYBREAK THURSDAY THAT MAY BRING BRIEF IFR CIGS/VSBY BUT MOST OTHER LOCATIONS SHOULD REMAIN VFR OVERNIGHT. CONVECTION REMAINS ISOLATED IN COVEARAGE THIS AFTERNOON AND SHORT-LIVED. GUST POTENTIAL IS AROUND 20 KT RANGE REMAINDER OF THIS AFTERNOON AND PROJECTED 25-30 KT RANGE THURSDAY. && .MARINE... BERMUDA RIDGE FLOW PATTERN SHOULD MAINTAIN RELATIVELY LIGHT WINDS AND LOW SEAS FOR THURSDAY AND FRIDAY. A COLD FRONT MOVING FROM THE NORTH IS LIKELY TO STALL BEFORE REACHING THE COAST LATE FRIDAY OR EARLY SATURDAY. MEANWHILE...AN EASTERLY WAVE WILL BE TRAVERSING THE NORTH GULF FRIDAY AND SATURDAY AND SHOULD INTERACT WITH THE FRONTAL ZONE TO POTENTIALLY PRODUCE GREATER COVERAGE OF TROPICAL SHOWERS AND THUNDERSTORMS IN THE NEAR COASTAL WATERS AND SOUNDS THIS WEEKEND. SEAS SHOULD REMAIN LESS THAN 2 FEET THROUGH MONDAY EVENING. && .DECISION SUPPORT... DSS CODE...GREEN. DEPLOYED...NONE. ACTIVATION...NONE. ACTIVITIES...SLURRY SUPPORT. 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 TO HIGH RISK SVR AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE. && .PRELIMINARY POINT TEMPS/POPS... MCB 72 90 72 89 / 10 30 20 50 BTR 73 91 73 90 / 10 30 20 50 ASD 74 90 73 90 / 10 30 20 50 MSY 77 90 77 90 / 10 40 20 50 GPT 76 89 75 90 / 20 40 20 50 PQL 73 90 72 89 / 20 40 20 50 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...NONE. GM...NONE. MS...NONE. GM...NONE. && $$ 24/RR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
153 PM EDT WED SEP 10 2014 .UPDATE... ISSUED AT 1149 AM EDT WED SEP 10 2014 GENERALLY MINOR TWEAKS TO THE GOING FORECAST...LARGELY WITH PINNING DOWN THE LOCATIONS OF THE HEAVIEST PRECIPITATION AND THEN WINDS FOR THIS AFTERNOON AND TONIGHT BEHIND THE LOW. AS FOR THE RAIN...ESSENTIALLY SEEING TWO AREAS OF PRECIPITATION...ONE OVER THE EAST ALIGNED WITH THE BROAD 850-500MB WARM AIR ADVECTION LIFTING TO THE NORTHEAST AHEAD OF THE LOW CENTERED OVER SOUTH CENTRAL WISCONSIN. EXPECT THAT AREA TO CONTINUE PUSHING TO THE NORTHEAST THROUGH THE DAY AND LARGELY DEPARTING BY LATE AFTERNOON. THE SECOND AREA IS FARTHEST TO THE WEST AND TIED TO THE 850-700MB FGEN AREA TO THE NORTHWEST OF THE MID LEVEL LOW. OBSERVER REPORTS INDICATE THIS AREA OF RAIN PRODUCING AROUND 0.5-0.75IN EVERY THREE HOURS AND THAT MATCHES DUAL POL INSTANTANEOUS PRECIP RATES. ALTHOUGH THIS AREA HAS BEEN PIVOTING AND SLOW TO MOVE THIS MORNING...IT IS EXPECTED TO SHIFT MORE TO THE EAST-NORTHEAST THIS AFTERNOON AS THE LOW QUICKLY MOVES NORTHEAST THROUGH NORTHERN LAKE MICHIGAN. STILL HAVE THE FLOOD WATCH IN PLACE AND THAT SEEMS REASONABLE OVER THE WEST (WITH THE ADDED PRECIP FROM OVERNIGHT PUSHING TOTALS OVER 2 INCHES IN SOME LOCATIONS). FROM MARQUETTE/DICKINSON COUNTY EAST...THINK THE POTENTIAL FOR FLOODING IS PRETTY LIMITED BUT WILL LEAVE WATCH IN PLACE AT THIS TIME. FINALLY FOR WINDS...MAIN ADJUSTMENTS WERE FOR AREAS OVER THE EAST AND NEAR LAKE MICHIGAN. EXPECT THE COMBINATION OF STRONG COLD AIR ADVECTION BEHIND THE LOW AND QUICK PRESSURE RISE TO LEAD TO GALES AND HAVE ISSUED A GALE WARNING FOR OUR LAKE MICHIGAN ZONES. DO HAVE A LITTLE CONCERN THAT GUSTS WILL BE NEAR 40-45MPH BRIEFLY LATE THIS AFTERNOON INTO THE EVENING NEAR THE LAKE SUPERIOR SHORELINE AND POTENTIALLY AT TIMES ELSEWHERE INLAND. THE OTHER AREA WAS OVER THE KEWEENAW PENINSULA...ALTHOUGH THE FORECAST WAS IN DECENT SHAPE...LATEST OBS AT KP59 INDICATE WINDS GUSTING TO NEAR WIND ADVISORY CRITERIA. WITH THE CENTRAL LAKE SUPERIOR BUOY GUSTING ABOVE 40KTS AND OTHER SITES NEAR WIND ADVISORY CRITERIA...WILL ISSUE A WIND ADVISORY FOR KEWEENAW AND NORTHERN HOUGHTON COUNTIES THROUGH THE EVENING HOURS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 533 AM EDT WED SEP 10 2014 LIGHT TO AT TIME HEAVY RAIN CONTINUES TO FALL OVER THE W THIRD OF UPPER MI THIS MORNING...ASSOCIATED WITH THE SFC TROUGH THAT PUSHED OVERHEAD EARLY THIS MORNING THE 500MB SHORTWAVE CROSSING WI...AND THE DEEPENING SFC LOW RIDING UP ALONG THE TROUGH NEARING FROM IA. THE LATEST SATELLITE AND RUC ANALYSIS SHOWS THIS INITIAL N SWATH OF MOISTURE EJECTING NE ACROSS THE CWA...WITH THE EFFECTS OF THE SW TO NE 100KT 250MB JET NEARING FROM THE PLAINS. THE SECONDARY AREA OF CLOUDS WILL BE IMPACTING THE E HALF OF THE CWA LATER THIS MORNING AND INTO THE AFTERNOON HOURS. EXACT RAINFALL TOTALS REMAIN TRICKY AS THERE ARE 2 AREAS OF THOUGHT. THE LATEST 06Z NAM PAINTS AN ADDITIONAL 1-2IN OVER CENTRAL AND E UPPER MI LATE THIS MORNING THROUGH EARLY THIS AFTERNOON. HOWEVER...THE 00Z GFS IS PUSHING MUCH OF THE MOISTURE JUST TO OUR E. HAVE GONE WITH A MIDDLE OF THE ROAD SOLUTION FOR THE MOMENT...KNOWING THAT CONVECTION TO THE SOUTH COULD STILL HURT THE INFLOW OF MOISTURE UP OUR WAY. STILL...ADDITIONAL SHOWERS CROSSING THE CWA THIS AFTERNOON WITH BE FACED WITH STIFF N ONSHORE FLOW...RESULTING IN A SLOWER N PROGRESSION AND OVERALL UPSLOPE ENHANCEMENT. SEE THE HYDROLOGY SECTION FOR MORE DETAILS ABOUT PRECIPITATION FOR THE REST OF TODAY. RAIN/RAIN SHOWERS WILL CONTINUE THROUGH TONIGHT...MAINLY ACROSS THOSE UPSLOPE AREAS OF CENTRAL UPPER MI. ADDITIONAL RAINFALL MAY ADD UP TO 0.25IN OR MORE ACROSS THE HURON MOUNTAINS. FCST MODELS ARE CONTINUING TO GO WITH THE SFC LOW TRACKING ACROSS N LOWER MI LATE THIS AFTERNOON...BEFORE EXITING INTO S ONTARIO AND W QUEBEC LATE THIS EVENING. TEMPERATURES WILL REMAIN TRICKY...AS THEY FALL W AND STILL RISE A COUPLE OF DEGREES AFTER SUNRISE E. KEPT THE WIND FCST VERY SIMILAR TO THE LAST COUPLE OF DAYS...WITH N-NNW GUSTS NEARING 35KTS FROM AROUND 18Z TODAY TO 08Z TONIGHT. AN SPS MAY BE NEEDED FOR THE W HALF AND HIGHER TERRAIN OF THE KEWEENAW PENINSULA...OR LOW END WIND ADVISORY TO HIGHLIGHT THE STRONG WINDS ON TOP OF SATURATED SOILS THAT MAY MORE EASILY UPROOT TREES THANKS TO THE ABUNDANT LEAVES. AS FOR THE OVERNIGHT HOURS...EXPECT SLOWLY DIMINISHING WINDS LATE AND COLD AIR TO FILTER IN WITH 850MB TEMPS OF -2 TO +4C BY DAYBREAK THURSDAY. DEPENDING ON HOW FAST RAIN CAN GET OUT OF THE INTERIOR AREAS ALONG THE WI BORDER...MID 30S LOWS WILL NOT BE OUT OF THE QUESTION. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 359 AM EDT WED SEP 10 2014 MAIN FCST CONCERNS IN THE LONG TERM FOCUS ON HOW QUICKLY ON THU CLDS AND SHOWERS ASSOCIATED WITH THE WED LO PRES WL EXIT THE CWA...TEMPS AND THE POTENTIAL FOR FROST ON THU NGT AND THEN ON POPS ACCOMPANYING THE PASSAGE OF ANOTHER DISTURBANCE THRU THE LOWER LKS ON FRI INTO SAT. SINCE AN UPR TROF WL DOMINATE ERN NAMERICA THRU NEXT WEEK... EXPECT BLO NORMAL TEMPS TO PREVAIL DURING THE EXTENDED PERIOD. THU...AS DEPARTING LO PRES OVER FAR SW QUEBEC AT 12Z THU SHIFTS TO THE ENE...STEADY N LLVL FLOW IS PROGGED TO WEAKEN AND BECOME MORE ACYC UNDER GENERAL DEEP LYR QVECTOR DVGC LEFT IN THE WAKE OF THE EXITING SHRTWV AND RDG AXIS EXPANDING TO THE E OF SFC HI CENTER IN THE NRN PLAINS. EXPECT PLENTY OF CLDS IN THE MRNG WITH SHOWERS MAINLY NEAR LK SUP ASSOCIATED WITH CHILLY LINGERING CYC FLOW OVER THE RELATIVELY WARM LK SUP WATERS. BUT WITH INCRSG SUBSIDENCE/ACYC FLOW IN THE PRESENCE OF DAYTIME HEATING...EXPECT THE SHOWERS TO DIMINISH AND THE CLD PATTERN TO SHIFT TO MORE INLAND SC COVERAGE UNDER THE H85 THERMAL TROF AND SUBSIDENCE INVRN SINKING TOWARD H85-9. H85 TEMPS IN THE ZERO TO -2C RANGE WL SUPPORT WELL BLO NORMAL HI TEMPS MAINLY IN THE UPR 40S/50S...COOLEST OVER THE HIER TERRAIN OF THE NW HALF. THU NGT...UNDER BLDG HI PRES WITH LOSS OF DAYTIME HEATING...EXPECT LINGERING SC TO DSPT IN THE EVNG AND GIVE WAY TO AT LEAST A PERIOD OF MOCLR SKIES AND LGT WINDS. WITH PWAT UNDER 0.5 INCH...TEMPS SHOULD FALL OFF STEADILY. THE ONE LIMITING FACTOR WL BE HOW QUICKLY HI CLDS IN ADVANCE OF SHRTWV MOVING THRU THE NRN PLAINS WL INVADE THE UPR LKS. SUSPECT THE COLD SPOTS OVER THE INTERIOR WL SEE TEMPS FALLING AOB 32...BUT WL HOLD OFF ON ANY KIND OF FREEZE WATCH/FROST HEADLINE GIVEN ACTIVE SHORT TERM...MARGINALLY LO ENUF FCST TEMPS AND COVERAGE OF THOSE REALLY LO TEMPS UNDER SOME INCRSG HI CLDS. FRI THRU SAT...ALTHOUGH THERE IS GOOD MODEL AGREEMENT ON THE TIMING AND TRACK OF A FAIRLY VIGOROUS SHRTWV THAT IS FCST TO MOVE E FM THE NRN ROCKIES ON THU AFTN THRU THE NCENTRAL PLAINS AND ACROSS THE LOWER LKS FRI NGT/SAT...THERE ARE SOME FAIRLY LARGE DIFFERENCES IN THE MSLP FIELDS AND QPF. THE 09/12Z ECWMF CONTINUES TO BE THE MODEL THAT SHOWS THE MORE IMPRESSIVE PRES FALL. WITH A DEEPER SFC REFLECTION...THE ECMWF ALSO SHOWS MORE EXPANSIVE MID LVL MSTR/PCPN EXTENDING INTO ALL OF UPR MI DURING FRI NGT/SAT MRNG. GIVEN THE POSITIVE TILT TO THE SHRTWV....EXPANSIVE HI PRES THAT IS FCST TO EXTEND FM THE NRN PLAINS INTO THE UPR LKS IN ADVANCE OF THIS SHRTWV AND DRY/STABLE NATURE OF THE ANTECEDENT AIRMASS /PWAT AOB 0.5 INCH WITH STRONG SUBSIDENCE INVRN BTWN H8-7/...SUSPECT THE NON-ECMWF MODELS SHOWING LESS SFC RESPONSE ARE ON THE RIGHT TRACK. HAVE THUS CHOSEN TO MAINTAIN ONLY LO CHC POPS...HIEST OVER THE SRN CWA CLOSER TO THE SHRTWV TRACK/AREA OF SHARPER DEEP LYR QVECTOR CNVGC. THICKER CLDS/THESE POPS WL ARRIVE ON FRI AFTN AS THE DISTURBANCE SLIDES INTO THE UPR MS RIVER VALLEY. ONCE THE SHRTWV PUSHES TO THE E ON SAT MRNG...TRAILING SHRTWV RDG/DRIER AIRMASS WL BRING A RETURN TO DRY WX/CLRG. WITH H85 TEMPS IN THE ZERO TO -2C RANGE DURING THIS TIME...THE WX WL BE UNSEASONABLY COOL. IF SKIES CLR FAST ENUF LATE FRI NGT...NOT OUT OF THE QUESTION THERE COULD BE SOME FROST OVER THE INTERIOR W ARND SUNRISE ON SAT. EXTENDED...AFTER A DRY PERIOD ASSOCIATED WITH SFC HI PRES PASSING THRU THE LOWER LKS ON SAT NGT...ANOTHER CNDN SHRTWV DIGGING THRU THE MEAN UPR TROF CENTERED OVER HUDSON BAY AND INTO THE NCENTRAL CONUS WL BRING A CHC OF MORE SHOWERS FOR SUN THRU MON. THIS DISTURBANCE WL BE MSTR DEPRIVED...SO NO HEAVY RA IS LIKELY. HI PRES MOVING E UNDER THE RISING HGTS IN THE WAKE OF THIS DISTURBANCE SHOULD BRING A RETURN OF DRY WX FOR TUE. WITH THE MEAN TROF IN PLACE...TEMPS ACRS UPR MI WL AVG BLO NORMAL DURING THIS TIME. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 152 PM EDT WED SEP 10 2014 A STRONG LOW PRESSURE SYSTEM MOVING NORTHEAST FROM SOUTH CENTRAL WISCONSIN THROUGH NORTHERN LOWER MICHIGAN AND THEN INTO QUEBEC WILL BRING GUSTY NORTH-NORTHEAST WINDS THROUGH TONIGHT. MODERATE RAIN WILL CONTINUE OVER THE NEXT FEW HOURS BEFORE TRANSITIONING TO LAKE EFFECT RAIN AT ALL THREE SITES FOR TONIGHT. THE ABUNDANT MOISTURE WITH THIS SYSTEM WILL PRODUCE IFR CEILINGS THIS AFTERNOON WHICH WILL GRADUALLY RISE TO MVFR TONIGHT INTO THURSDAY MORNING AS THE LOW MOVES AWAY. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 359 AM EDT WED SEP 10 2014 AS A DEEP LO PRES MOVES NE THRU THE UPPER MIDWEST AND ACROSS NORTHERN LOWER MI THIS EVENING ON ITS WAY INTO SE CANADA TONIGHT...THE NE GALES AFFECTING WESTERN LAKE SUPERIOR WILL SPREAD E OVER THE REST OF THE LAKE. EXPECT NNE GALES AS HI AS 40-45 KTS TODAY INTO TONIGHT BEFORE THE LO PRES SHIFTS FAR ENOUGH TO THE E AND THE GALES DIMINISH W TO E TONIGHT. AS HI PRES BUILDS TOWARD LAKE SUPERIOR FROM THE PLAINS ON THU...LINGERING N WINDS UP TO 25-30 KTS IN THE MORNING WILL DIMINISH W-E TO UNDER 15-20 KTS BY THE EVENING. RELATIVELY LIGHT WINDS UNDER 20 KTS WILL THEN DOMINATE THRU THE WEEKEND UNDER A RELATIVELY WEAK PRES GRADIENT. && .HYDROLOGY... ISSUED AT 426 AM EDT WED SEP 10 2014 RAINFALL OVER THE W THIRD OF UPPER MI HAS BEEN CONVECTIVELY ENHANCED...WITH RAINFALL RATES BRIEFLY RISING TO NEAR 6IN PER HOUR. WITH THE QUICK MOVEMENT TO THE N JUST OVER 20KTS THAT AMOUNT WAS NOT REALIZED. RADAR ESTIMATES THROUGH 08Z HAVE THE HIGHEST AMOUNTS OVER NW GOGEBIC AND ALONG THE E ONTONAGON/W HOUGHTON COUNTIES...WITH 1.5 TO 2.25IN. SOME LOCAL RIVERS CONTINUE TO RESPOND TO THE RAINFALL A FEW DAYS AGO...AND ARE RISING AT AN INCREASED RATE DO TO THE CURRENT RAIN. SPECIFICALLY THIS INCLUDES THE SOUTH BRANCH OF THE ONTONAGON RIVER AT EWEN /WHICH GIVEN THE TREND WILL SEE A SLOW RISE FOR THE NEXT SEVERAL DAYS/. THE MIDDLE BRANCH OF THE ONTONAGON RIVER AT PAULDING IS ALSO SLOWLY ON THE RISE. OTHERWISE AN AVERAGED 0.5IN HAS FALLEN W OF A LINE FROM IRON RIVER TO BARAGA. LITTLE RAIN HAS FALLEN E OF THIS LINE...WHICH WILL CHANGE OVER THE NEXT COUPLE OF HRS AS ADDITIONAL SHOWERS NEAR FROM WI. THUNDERSTORMS ARE MINIMAL OVER WI...AND PRECIP IS SLOWER THAN ORIGINALLY ANTICIPATED. HAVE BACKED OFF ON THE STORM TOTAL PRECIP OVER THE E THIRD OF THE FCST AREA AS A RESULT. EXPECT THE TRADITIONAL URBAN/SMALL STREAM FLOODING TO BE A SIGNIFICANT POSSIBILITY IN THE TYPICAL POOR DRAINAGE AREAS OF ESC IF A PERIOD OF HEAVIER DOWNPOURS DEVELOP WITH RAINFALL RATES CLOSE TO AN 0.5-1.0 INCH PER HOUR. N CNTRL UPPER MI WILL STILL LIKELY SEE SOME UPSLOPE LAKE ENHANCEMENT TODAY-TONIGHT. THE FLOOD WATCH REMAINS POSTED FOR MUCH OF W AND CENTRAL UPPER MI FOR TODAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... FLOOD WATCH UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR MIZ001>006-009>013-084. WIND ADVISORY UNTIL 2 AM EDT THURSDAY FOR MIZ001-003. LAKE SUPERIOR... GALE WARNING FROM 8 PM THIS EVENING TO 8 AM EDT THURSDAY FOR LSZ251-267. GALE WARNING UNTIL 5 AM EDT THURSDAY FOR LSZ246>250-265-266. GALE WARNING UNTIL 4 AM EDT THURSDAY FOR LSZ243>245-264. GALE WARNING UNTIL 2 AM EDT /1 AM CDT/ THURSDAY FOR LSZ240>242- 263. GALE WARNING UNTIL 11 PM EDT /10 PM CDT/ THIS EVENING FOR LSZ162. LAKE MICHIGAN... GALE WARNING UNTIL 8 AM EDT THURSDAY FOR LMZ221-248-250. && $$ UPDATE...SRF SHORT TERM...KF LONG TERM...KC AVIATION...SRF MARINE...KC HYDROLOGY...KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
111 PM CDT WED SEP 10 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 327 AM CDT WED SEP 10 2014 MODERATE TO HEAVY RAIN CONTINUES OVER MUCH OF EAST CENTRAL MN AND WEST CENTRAL WISCONSIN. ALTHOUGH THE GREATER MOISTURE TRANSPORT HAS EXITED TO THE SOUTHEAST OF THE AREA...FAIRLY STRONG MID LEVEL FRONTOGENESIS REMAINS OVER TWO SPECIFIC AREAS OF THE CWA. ONE OVER EAST CENTRAL MN AND NORTHWEST WISCONSIN AND THE OTHER DEVELOPING TO THE SOUTHEAST...MOVING NOW INTO WEST CENTRAL WISCONSIN. THE RUC AND NAM SHOW THIS GRADUALLY WEAKENING AND LIFTING OFF TO THE EAST DURING THE MORNING. THIS SHOULD TAKE THE RAIN WITH IT. THE THREAT OF PONDING WATER REMAINS MAINLY ACROSS WEST CENTRAL WISCONSIN INTO THE MORNING. COLLABORATION WITH SURROUNDING OFFICES DID YIELD THE CONTINUATION OF THE FLOOD WATCH INTO WEST CENTRAL WISCONSIN. TODAYS HIGH TEMPERATURES WILL LIKELY OCCUR THIS MORNING AS WELL. THEY MAY CONTINUE TO DROP OFF THROUGH MID MORNING OR SO BEFORE LEVELING OFF INTO THE AFTERNOON. STRONG NORTH WINDS RE EXPECTED TO DEVELOP EAST AS LOW LEVEL CAA SPREADS OVER THE REGION. CLOUDS ARE EXPECTED TO HANG TOUGH OVER MUCH OF THE AREA INTO THE NIGHT. THERE IS SOME INDICATION THAT IN THE WAKE OF THE TROUGH...SUBSIDENCE COULD BE STRONG ENOUGH TO ERODE THE LOWER CLOUD COVER. WINDS WILL SLOWLY DIMINISH AS THE LOW CONTINUE TO LIFT EAST/NORTHEAST INTO THE NIGHT. IT SHOULD COOL RAPIDLY IF BREAKS DO DEVELOP INTO THE NORTH CENTRAL CWA DURING THE NIGHT. SOME UPPER 30S POSSIBLE WHERE THIS OCCURS. READINGS IN THE LOWER 40S SHOULD REMAIN ELSEWHERE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 327 AM CDT WED SEP 10 2014 THE LONG TERM FORECAST WILL FEATURE THE PASSAGE OF A SHORTWAVE TROUGH AT THE BEGINNING OF THE PERIOD...FOLLOWED BY BRIEF SEMI- ZONAL FLOW OVER THE WEEKEND...AND THEN A PATTERN TRANSITION TO WESTERN RIDGING AND EASTERN TROUGHING THROUGH THE FIRST HALF OF NEXT WEEK. ON THURSDAY...A BROAD SURFACE HIGH BECOMES ESTABLISHED ACROSS THE NATION/S MIDSECTION...WHILE A WEAK SHORTWAVE SLIDES EAST/SOUTHEAST ACROSS THE AREA FROM THE NORTHERN/CANADIAN ROCKIES. WHILE THE BETTER FORCING AND MORE PLENTIFUL MOISTURE WILL LIE SOUTH OF THE FORECAST AREA...COULD SEE A FEW SHOWERS SNEAK INTO SOUTHERN MN AND WEST CENTRAL WI LATE THURSDAY NIGHT AND FRIDAY. TEMPERATURES WILL BE COOL...WITH HIGHS IN THE 50S ON THURSDAY AND FRIDAY...AND LOWS DIPPING INTO THE MID TO UPPER 30S. DEPENDING ON HOW THE CLEARING GOES AND WINDS...COULD POSSIBLY SEE SOME FROST ON SATURDAY MORNING. SATURDAY LOOKS TO HAVE THE HIGHEST POTENTIAL TO BE AN ENTIRELY DRY DAY...AS SURFACE HIGH PRESSURE PREVAILS AND IN THE ABSENCE OF ANY MID/UPPER DISTURBANCES. SUNDAY BRINGS THE ARRIVAL OF WEAK SHORTWAVE ENERGY IN THE BASE OF THE MANITOBA/ONTARIO TROUGH. MOISTURE AND FORCING ARE THE MOST ROBUST NORTH AND EAST OF THE FORECAST AREA...BUT SUFFICIENT TO WARRANT 20 POPS LOCALLY. ON MONDAY...THINGS START TO DRY OUT WITH THE PATTERN EVOLUTION TO WESTERN RIDGING. OVERALL...SHOULD BE DRY WITH SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH MID-WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 111 PM CDT WED SEP 10 2014 LOW MVFR CEILINGS WILL IMPROVE TO VFR FROM NW TO SE DURING THE LATE AFTERNOON AND EVENING HOURS AS A LOW PRESSURE SYSTEM NEAR KGRB CONTINUES TO MOVE NORTHEAST. MAIN CHANGE FROM THE PREVIOUS SET WAS TO DELAY THE IMPROVEMENT TO VFR BY A FEW HOURS. THE ONE AREA THAT MAY STILL END UP BEING TOO QUICK WITH THE IMPROVEMENT IS KEAU WHERE THE LOW LEVEL CYCLONIC FLOW PERSISTS THROUGH THE NIGHT. VFR DAY ON THURSDAY AND THERE MAY BE SOME SPRINKLES OR LIGHT RAIN OVER WEST CENTRAL AND SOUTHWEST MN AS A WEATHER DISTURBANCE DROPS SOUTHWARD THROUGH THE NORTHERN AND CENTRAL PLAINS. NORTH WINDS THIS AFTERNOON FROM 15 TO 20 KNOTS WITH GUSTS TO 25 KNOTS...WILL DIMINISH TO 10 KNOTS OR LESS TONIGHT. NORTH WINDS 10 TO 15 KNOTS ON THURSDAY. KMSP...MVFR CEILINGS FORECAST TO PERSIST INTO EARLY THIS EVENING WHICH IS A FEW HOURS LATER THAN THE PREVIOUS TAF. VFR THEREAFTER WITH CEILINGS AOA 050. NORTH WINDS GUSTING UP TO 30 KNOTS EARLY THIS AFTERNOON THEN DIMINISHING QUICKLY THIS EVENING. /OUTLOOK FOR KMSP/ FRI...VFR. WINDS NW AT 5-10 KNOTS. SAT...VFR. WINDS SW 5-10 KNOTS. SUN...VFR. WINDS SW 10 KNOTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...DWE LONG TERM...LS AVIATION...RAH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
437 PM CDT WED SEP 10 2014 .UPDATE... ISSUED AT 437 PM CDT WED SEP 10 2014 QUICK UPDATE TO EXPAND AN ISOLATED MENTION OF RAIN SHOWERS THROUGH SOUTH CENTRAL NORTH DAKOTA THIS EVENING. LATEST BISMARCK AND BOWMAN RADARS SHOWING AN AREA OF LIGHT RAIN SHOWERS MOVING EAST OUT OF THE SOUTHWEST. A MID LEVEL CIRCULATION LOCATED IN THE WEST WILL SLIDE EAST EARLY THIS EVENING...AND CONCUR WITH HIGHER RESOLUTION MODELS OF THE RAP AND HRRR...THIS PRECIPITATION WEAKENS BUT ALSO EXPANDS INTO SOUTH CENTRAL NORTH DAKOTA INCLUDING THE SOUTHERN JAMES RIVER VALLEY BETWEEN 00Z AND 03Z. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 255 PM CDT WED SEP 10 2014 THE MAJOR FORECAST CHALLENGE WILL BE THE FROST POTENTIAL TONIGHT. THE LATEST SHORT RANGE MODEL GUIDANCE CONTINUES TO PROG BOUNDARY LAYER MOISTURE TO ERODE TO THE SOUTHWEST AS DRIER AIR GETS USHERED IN FROM THE NORTHEAST. FURTHERMORE...BOUNDARY LAYER WINDS ARE FORECAST TO WEAKEN TO AROUND 10 KNOTS TONIGHT AS HIGH PRESSURE SETTLES INTO MONTANA. HOWEVER...THE LATEST GUIDANCE CONTINUES TO PROG MID-LEVEL MOISTURE/CLOUDS (USING 850MB-500MB LAYER RH FIELDS) TO STREAM OVER MOST OF WESTERN AND CENTRAL NORTH DAKOTA TONIGHT AHEAD OF A SHORTWAVE ROTATING INTO MONTANA. THIS WOULD LIKELY INHIBIT COOLING TEMPERATURES. BALANCING WHERE THE CLEARING SKIES ARE FORECAST...WINDS WEAKENING OVERNIGHT...AND BOUNDARY LAYER TEMPERATURES...THINK THE TURTLE MOUNTAIN AREA WILL HAVE THE BEST CHANCE OF SEEING A FROST BETWEEN 09Z-14Z THURSDAY MORNING. AS A RESULT...ISSUED A FROST ADVISORY FOR BOTTINEAU...ROLETTE...AND PIERCE COUNTIES FOR SAID TIME PERIOD. TO THE SOUTHWEST...THERE WILL BE A CHANCE FOR A RAIN/SNOW MIX AFTER MIDNIGHT. HOWEVER...ACCUMULATIONS SHOULD BE LIGHT. FOR THURSDAY...DEEP MOISTURE AND ASSOCIATED PRECIP CHANCES WILL CONTINUE TO PUSH SOUTH OF THE STATE AS HIGH PRESSURE BUILDS INTO THE REGION. WELL BELOW NORMAL HIGHS ARE EXPECTED ONCE AGAIN WITH READINGS RANGING FROM THE MID 40S SOUTHWEST TO THE MID 50S EAST. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 255 PM CDT WED SEP 10 2014 FOCUS IN THE LONG TERM WILL BE ON THE POTENTIAL FOR WIDESPREAD FROST AND A FREEZE FRIDAY MORNING. MODEL GUIDANCE CONTINUES TO SHOW LOWS IN THE UPPER 20S ACROSS THE WEST AND LOWER 30S ELSEWHERE. WITH A LARGE SURFACE HIGH OVER THE NORTHERN PLAINS WINDS WILL BE LIGHT. THE BIGGEST QUESTION WILL BE HOW FAST CLOUDS CLEAR OUT. DEEP MOISTURE ACROSS THE STATE WILL BEGIN TO CLEAR OUT QUICKLY AROUND 18 UTC THURSDAY...HOWEVER THE 12 UTC MODEL GUIDANCE SHOWS A THIN LAYER OF LOW TO MID LEVEL MOISTURE HANGING AROUND THROUGH 06 UTC FRIDAY. REGARDLESS AT LEAST PATCHY FROST SEEMS LIKELY ACROSS CENTRAL AND WESTERN NORTH DAKOTA. WIDESPREAD FROST IS LOOKING THE MOST LIKELY ACROSS THE NORTHWEST AS CLOUD COVER WILL CLEAR FROM NORTH TO SOUTH. THE NORTH WILL ALSO HAVE THE BEST OPPORTUNITY FOR A FREEZE AS LOWS WILL MOSTLY BE BELOW FREEZING...ESPECIALLY NORTHWEST. AS FOR THE SOUTH HAVE LIMITED THE WORDING FOR FROST AT AREAS FOR NOW AS CLOUD COVER MAY STICK AROUND LONG ENOUGH TO PREVENT WIDESPREAD FROST DEVELOPMENT. FOR THE SAME REASON THERE IS LESS OF A CHANCE OF A FREEZE ACROSS THE SOUTH. TEMPERATURES WILL ALSO DROP LOW ENOUGH ON SATURDAY MORNING ACROSS THE SOUTH...ESPECIALLY FOR THE SOUTHWEST...FOR SOME PATCHY FROST. FOR THE REMAINDER OF THE LONG TERM THE 12 UTC MODEL GUIDANCE CONTINUES TO SHOW A MEAN TROUGH OVER THE U.S. THE 12 UTC GFS AND ECMWF SHOW ANOTHER SHORT WAVE RIDING DOWN THE LEE OF THE CANADIAN ROCKIES INTO THE NORTHERN PLAINS LATE SATURDAY INTO SUNDAY. MODELS ARE NOT SHOWING MUCH PRECIPITATION WITH THIS SYSTEM AND THE REMAINDER OF THE LONG TERM IS ALSO LOOKING MOSTLY DRY AND WARMER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1157 AM CDT WED SEP 10 2014 VFR CIGS WILL PREVAIL OVER KISN-KMOT-KBIS-KJMS THROUGH THE TAF PERIOD. OTHERWISE...MVFR CONDITIONS ARE EXPECTED OVER KDIK THROUGH THE LATE EVENING HOURS. MVFR CIGS SHOULD IMPROVE TO VFR OVER SOUTHWESTERN NORTH DAKOTA TONIGHT. SEE INDIVIDUAL KDIK TAF FOR DETAILS. && .BIS WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY FROM 4 AM TO 9 AM CDT THURSDAY FOR NDZ004-005-013. && $$ UPDATE...KS SHORT TERM...TM LONG TERM...MM AVIATION...TM
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
128 PM EDT WED SEP 10 2014 .SYNOPSIS... LOW PRESSURE OVER IOWA WILL MOVE ACROSS LAKE HURON PULLING A STRONG COLD FRONT ACROSS THE AREA WEDNESDAY NIGHT. A WAVE OF LOW PRESSURE WILL MOVE UP THE OHIO VALLEY FRIDAY NIGHT INTO SATURDAY THEN HIGH PRESSURE OVER THE NORTHERN PLAINS WILL MOVE EAST THROUGH THE REGION SUNDAY AND MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATE...MADE MORE ADJUSTMENTS TO POPS AND WX BASED ON CURRENT RADAR TRENDS AND HRRR PROGS. ORIGINAL...THE QUESTION TODAY IS HOW FAR OUT AHEAD OF THE APPROACHING COLD FRONT WILL THE TSRA OCCUR. THE LATEST MODEL RUNS HAVE QPF RAPIDLY SPREADING ESE ACROSS THE CWA BETWEEN 18Z AND 00Z. WILL INCREASE POPS MORE FOR TODAY. THE THREAT FOR SEVERE STORMS STILL LOOKS GOOD BASED ON INSTABILITY AND FAIRLY GOOD WIND SHEAR. PW`S RISE BACK TO AROUND 2 INCHES SO LOCALLY HEAVY RAIN CAN BE EXPECTED. PATCHY MORNING FOG IN THE SOUTH WILL DISSIPATE THROUGH 10 AM. TODAY WILL BE THE LAST RELATIVELY WARM DAY FOR A WHILE...POSSIBLY THE REST OF THE SEASON BASED ON UPPER TROUGHING THAT IS GOING TO SET UP OVER THE LAKES FOR AT LEAST THE NEXT 10 DAYS. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... A FINAL BAND OF TSRA WITH THE STRONG COLD FRONT SHOULD PROGRESS ACROSS THE CWA BETWEEN 06Z AND 12Z SO AFTER 12Z THU ONLY THE SE HALF OF THE CWA SHOULD STILL HAVE A THREAT FOR RAIN WITH THE STRONGER CONVECTION THEN EXITING THE CWA. DRIER AIR MOVES IN BEHIND THE FRONT ALONG WITH THE LEADING PART OF A MUCH COOLER AIRMASS. MARGINAL LAKE EFFECT CONDITIONS START TO DEVELOP BY THE END OF THU NIGHT SO A FEW SHRA COULD BREAK OUT OVER THE SNOWBELT AND NEARBY AREAS. A SHARP S/W IS PROGGED TO MOVE EAST ACROSS THE LAKES FRI NIGHT INTO SAT AND INDUCE A SURFACE WAVE THAT MOVES UP THE OH VALLEY. MOISTURE POOLS BACK OVER THE AREA WITH WIDESPREAD SHRA DEVELOPING FRI NIGHT AND CONTINUING INTO SAT BEFORE SHIFTING INTO MAINLY THE EAST SAT AFTERNOON. HIGH PRESSURE IS SHOWN TO BE QUICKLY SPREADING OVER THE AREA BY SAT NIGHT BUT LAKE EFFECT CONDITIONS ARE POSSIBLE BASED ON TEMP DIFFERENCES. DUE TO WIND ISSUES AND SUBSIDENCE FROM THE HIGH WILL KEEP ONLY A SLIGHT CHANCE GOING SAT NIGHT IN THE NE. TEMPS WILL TREND COOLER FOR FRI AND SAT WITH HIGHS BOTH DAYS MOSTLY 60 TO 65 DEGREES. SOME SPOTS ON SAT MAY NOT EVEN GET TO 60 DEGREES IN THE INLAND EAST IF CLOUD COVER AND SHRA PERSIST. THE INCREASING CLOUDS FRI NIGHT SHOULD HOLD UP LOWS IN A 45 TO 50 RANGE BUT BY SAT NIGHT THE DECREASED CLOUDS AND LIGHT WINDS WILL ALLOW FOR LOWS IN THE LOW TO MID 40S. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... COOL HIGH PRESSURE WILL BE IN CONTROL OF THE REGION ON SUNDAY BUT IT WILL BE SHIFTING OFF TO THE EAST AS ANOTHER UPPER LEVEL TROUGH DIGS INTO THE GREAT LAKES REGION. AS THIS TROUGH MOVES OVERHEAD IT WILL BRING AN INCREASING CHANCE OF SHOWERS. THE BETTER CHANCES OF THE SHOWERS WILL BE MONDAY NIGHT INTO TUESDAY. THE SHOWERS MAY LINGER DOWNWIND OF LAKE ERIE INTO TUESDAY EVENING. THE NEXT AREA OF HIGH PRESSURE WILL THEN DRY THINGS OUT TUESDAY NIGHT INTO WEDNESDAY. IT WILL BE COOL THROUGH THE LONG TERM WITH TEMPERATURES BELOW SEASONAL AVERAGES. HIGHS AT MOST LOCATIONS WILL REMAIN IN THE 60S. HOWEVER BY TUESDAY AND WEDNESDAY THE WESTERN COUNTY WARNING AREA WILL BE NEAR TO SLIGHTLY ABOVE 70. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... SHOWERS WITH A FEW EMBEDDED TSRA MOVING THROUGH THIS EVENING ASSOCIATED WITH WARM FRONT LIFTING ACROSS FORECAST AREA. QUESTION REMAINS HOW STRONG THE TSRA WILL BE. SPC HAS MOST OF THE AERA IN SLIGHT RISK FOR SEVERE FOR THIS EVENING. WITH A 50 KT JET AT 2K FT MOVING INTO NW OH EXPECT TSRA TO INCREASE IN COVERAGE...HOWEVER THAT SAID NOT SURE HOW WIDESPREAD TSRA WILL BECOME AS RAINSHOWERS HAVE BEEN STABILIZING ATMOSPHERE. WILL LEAVE IN A FEW HOURS OF TEMPO TSRA FOR NOW IN THE TAFS. EXPECT IFR CIGS TO DEVELOP OVERNIGHT AS A COLD FRONT MOVES ACROSS THE FORECAST AREA TONIGHT. OUTLOOK...NON VFR POSSIBLE THURSDAY IN SHOWERS AND THUNDERSTORMS. LOWER CEILINGS MAY LINGER OVER NE OHIO AND NW PA INTO FRIDAY AND SATURDAY. && .MARINE... LOW PRESSURE WILL MOVE INTO THE CENTRAL GREAT LAKES TODAY WITH INCREASING SOUTH TO SOUTHWEST WINDS EXPECTED INTO THIS EVENING. WINDS WILL INCREASE THE EARLIEST ACROSS THE WESTERN BASIN WITH SOUTHERLY WINDS IN THE 15 TO 25 KNOT RANGE. WINDS WILL BE OFFSHORE SO WAVES SHOULD NOT BUILD ALL THAT MUCH. SINCE WINDS ARE EXPECTED TO BE IN THE 15 TO 25 KNOT RANGE WE HOISTED THE SMALL CRAFT ADVISORY FOR THIS AFTERNOON. WINDS WILL EVENTUALLY SHIFT AROUND TO THE WEST AND NORTHWEST IN THE WAKE OF THE COLD FRONT TONIGHT. THE FRONT SHOULD BE EAST OF THE LAKE BY 12Z THURSDAY. THE REMAINDER OF THE LAKE WILL NEED TO HAVE A SMALL CRAFT ADVISORY AT SOME POINT THIS EVENING INTO THE OVERNIGHT. LATER SHIFTS WILL ISSUE IT WHEN IT IS NEEDED. THE COLD ADVECTION IN THE WAKE OF THE FRONT WILL KEEP LARGER WAVES (4-6 FEET) GOING INTO AT LEAST THURSDAY AFTERNOON/EVENING. AS HIGH PRESSURE RIDGES OVER THE REGION WINDS WILL BECOME NORTHEAST BY FRIDAY MORNING. THIS WILL SET UP A LONG FETCH INTO THE WESTERN HALF OF THE LAKE. IF THE PRESSURE GRADIENT CAN REMAIN TIGHT ENOUGH WE MAY NEED SMALL CRAFT ADVISORIES AGAIN FRIDAY INTO SATURDAY. MORE DETAILS TO COME ON THIS SCENARIO THE NEXT COUPLE DAYS. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE FRONT AND TRACK ACROSS MUCH OF THE LAKE. A FEW OF THESE THUNDERSTORMS WILL BECOME STRONG ENOUGH TO WARRANT THE ISSUANCE OF SPECIAL MARINE WARNINGS FOR THIS EVENING AND POSSIBLY INTO THE OVERNIGHT. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EDT THURSDAY FOR LEZ142>145. && $$ SYNOPSIS...ADAMS NEAR TERM...ADAMS/TK SHORT TERM...ADAMS LONG TERM...MULLEN AVIATION...DJB MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS NORMAN OK
559 PM CDT WED SEP 10 2014 .AVIATION... 0Z TAFS... VFR/MVFR CEILINGS EXPECTED FOR THIS TAF PERIOD. SHOWERS/STORMS WILL BE POSSIBLE ACROSS THE SOUTHERN HALF OF THE AREA THROUGHOUT THE PERIOD BUT MOST LIKELY SITES TO RECEIVE RAIN WILL BE OVER THE NEXT FEW HOURS IN CENTRAL OK W/STRONGEST STORMS REMAINING SOUTH AND EAST OF THE TAF SITES. && .PREV DISCUSSION... /ISSUED 356 PM CDT WED SEP 10 2014/ DISCUSSION... THE INITIAL COLD FRONT IS CURRENTLY MOVING THROUGH SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS. HRRR SUGGESTS THUNDERSTORMS MAY STILL DEVELOP AHEAD OF THE FRONT IN FAR SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS LATE AFTERNOON INTO THE EVENING. THERE WILL ALSO BE POST-FRONTAL PRECIPITATION...SO KEPT POPS BEHIND THE FRONT TONIGHT. MOST AREAS SHOULD BE DRY DURING THE DAY TOMORROW. ONLY A CHANCE ACROSS SOUTHERN OK AND WESTERN NORTH TX. A SECONDARY...STRONGER COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA ON FRIDAY. AHEAD OF THE SECONDARY FRONT...ISENTROPIC ASCENT WILL BE PRESENT NEAR THE 305K SFC THURSDAY NIGHT INTO FRIDAY MORNING. THE GREATEST ISENTROPIC ASCENT AND ELEVATED INSTABILITY APPEARS TO BE ACROSS SOUTHERN OKLAHOMA...ESPECIALLY EAST OF I-35. EXPECT SHOWERS AND THUNDERSTORMS DURING THIS PERIOD IN SOUTHERN OKLAHOMA. THE ASCENT AND ASSOCIATED PRECIPITATION SHOULD WEAKEN BY MID-MORNING. THE AIR MASS BEHIND THIS FRONT IS FAIRLY COLD AND IS ORIGINATING FROM A 1040 MB SFC HIGH IN WESTERN CANADA. THE FRONT APPEARS TO BE A TYPICAL SHALLOW COLD FRONT WHERE A THERMAL TROUGH/PRESSURE RIDGE DEVELOPS ACROSS THE HIGH PLAINS. LEANED TOWARD THE NAM12 BECAUSE IT SEEMS TO HAVE A MORE REALISTIC REPRESENTATION OF SURFACE FEATURES ON FRIDAY. BEHIND THE COLD FRONT...WIDESPREAD LOW CLOUDS AND LIGHT PRECIPITATION/DRIZZLE WILL RESULT IN STEADY OR FALLING TEMPERATURES DURING THE DAY FRIDAY. AREAS NORTH AND WEST WILL STAY IN THE 50S ALL DAY. EVEN CENTRAL OKLAHOMA MAY SEE TEMPERATURES FALL INTO THE 50S IN THE AFTERNOON. ASCENT SEEMS TO BE VERY WEAK BEHIND THE FRONT...SO EXPECT VERY LIGHT PRECIPITATION TOTALS. MAYBE SLIGHTLY HIGHER TOTALS IN NORTHWEST OK. LOW-LEVEL DRY AIR WILL FLOW IN FROM THE NORTH FRIDAY NIGHT. SKIES MAY CLEAR OUT ACROSS THE NORTHERN CWA. EXPECT SATURDAY MORNING WILL BE THE COLDEST MORNING IN THE NEXT WEEK. 40S WILL BE LIKELY NORTH OF I-40. IT WOULD NOT BE SURPRISING TO SEE A COUPLE UPPER 30S NEAR THE KANSAS BORDER IF SKIES CAN COMPLETELY CLEAR. SOUTH OF I-40...STRONGER WINDS AND CLOUD COVER MAY KEEP TEMPERATURES FROM BOTTOMING OUT. LOW TO MID 50S WILL BE POSSIBLE THERE. SATURDAY...MOSTLY SUNNY SKIES ARE EXPECTED ACROSS THE NORTHERN TWO THIRDS OF THE CWA. LOW-LEVEL RH FIELDS SUGGEST MORE WIDESPREAD CLOUDS MAY STICK AROUND ACROSS FAR SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS. HIGH TEMPERATURES WILL BE 10 TO 15 DEGREES BELOW AVERAGE SATURDAY AFTERNOON. AS A LEE TROUGH DEVELOPS...RETURN SOUTHERLY FLOW WILL RESULT IN A MODERATING TREND ON SUNDAY. HIGHS WILL BE SEASONABLE IN THE LOW TO MID 80S. A COLD FRONT WILL APPROACH NORTHERN OKLAHOMA LATE MONDAY INTO TUESDAY. THERE IS SOME UNCERTAINTY ON HOW FAR SOUTH THE FRONT WILL GO. NEVERTHELESS...THE FRONT AND NORTHWEST FLOW ALOFT SUGGEST AT LEAST LOW POPS ARE NEEDED LATE MONDAY THROUGH WEDNESDAY. MAHALE && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 62 76 61 65 / 20 10 30 40 HOBART OK 60 76 59 67 / 20 10 30 50 WICHITA FALLS TX 65 80 64 72 / 40 30 50 50 GAGE OK 53 73 51 58 / 0 10 30 50 PONCA CITY OK 57 75 55 63 / 0 10 20 40 DURANT OK 68 80 68 72 / 60 40 60 50 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 30/25/25
AREA FORECAST DISCUSSION
NWS NORMAN OK
356 PM CDT WED SEP 10 2014 .DISCUSSION... THE INITIAL COLD FRONT IS CURRENTLY MOVING THROUGH SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS. HRRR SUGGESTS THUNDERSTORMS MAY STILL DEVELOP AHEAD OF THE FRONT IN FAR SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS LATE AFTERNOON INTO THE EVENING. THERE WILL ALSO BE POST-FRONTAL PRECIPITATION...SO KEPT POPS BEHIND THE FRONT TONIGHT. MOST AREAS SHOULD BE DRY DURING THE DAY TOMORROW. ONLY A CHANCE ACROSS SOUTHERN OK AND WESTERN NORTH TX. A SECONDARY...STRONGER COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA ON FRIDAY. AHEAD OF THE SECONDARY FRONT...ISENTROPIC ASCENT WILL BE PRESENT NEAR THE 305K SFC THURSDAY NIGHT INTO FRIDAY MORNING. THE GREATEST ISENTROPIC ASCENT AND ELEVATED INSTABILITY APPEARS TO BE ACROSS SOUTHERN OKLAHOMA...ESPECIALLY EAST OF I-35. EXPECT SHOWERS AND THUNDERSTORMS DURING THIS PERIOD IN SOUTHERN OKLAHOMA. THE ASCENT AND ASSOCIATED PRECIPITATION SHOULD WEAKEN BY MID-MORNING. THE AIR MASS BEHIND THIS FRONT IS FAIRLY COLD AND IS ORIGINATING FROM A 1040 MB SFC HIGH IN WESTERN CANADA. THE FRONT APPEARS TO BE A TYPICAL SHALLOW COLD FRONT WHERE A THERMAL TROUGH/PRESSURE RIDGE DEVELOPS ACROSS THE HIGH PLAINS. LEANED TOWARD THE NAM12 BECAUSE IT SEEMS TO HAVE A MORE REALISTIC REPRESENTATION OF SURFACE FEATURES ON FRIDAY. BEHIND THE COLD FRONT...WIDESPREAD LOW CLOUDS AND LIGHT PRECIPITATION/DRIZZLE WILL RESULT IN STEADY OR FALLING TEMPERATURES DURING THE DAY FRIDAY. AREAS NORTH AND WEST WILL STAY IN THE 50S ALL DAY. EVEN CENTRAL OKLAHOMA MAY SEE TEMPERATURES FALL INTO THE 50S IN THE AFTERNOON. ASCENT SEEMS TO BE VERY WEAK BEHIND THE FRONT...SO EXPECT VERY LIGHT PRECIPITATION TOTALS. MAYBE SLIGHTLY HIGHER TOTALS IN NORTHWEST OK. LOW-LEVEL DRY AIR WILL FLOW IN FROM THE NORTH FRIDAY NIGHT. SKIES MAY CLEAR OUT ACROSS THE NORTHERN CWA. EXPECT SATURDAY MORNING WILL BE THE COLDEST MORNING IN THE NEXT WEEK. 40S WILL BE LIKELY NORTH OF I-40. IT WOULD NOT BE SURPRISING TO SEE A COUPLE UPPER 30S NEAR THE KANSAS BORDER IF SKIES CAN COMPLETELY CLEAR. SOUTH OF I-40...STRONGER WINDS AND CLOUD COVER MAY KEEP TEMPERATURES FROM BOTTOMING OUT. LOW TO MID 50S WILL BE POSSIBLE THERE. SATURDAY...MOSTLY SUNNY SKIES ARE EXPECTED ACROSS THE NORTHERN TWO THIRDS OF THE CWA. LOW-LEVEL RH FIELDS SUGGEST MORE WIDESPREAD CLOUDS MAY STICK AROUND ACROSS FAR SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS. HIGH TEMPERATURES WILL BE 10 TO 15 DEGREES BELOW AVERAGE SATURDAY AFTERNOON. AS A LEE TROUGH DEVELOPS...RETURN SOUTHERLY FLOW WILL RESULT IN A MODERATING TREND ON SUNDAY. HIGHS WILL BE SEASONABLE IN THE LOW TO MID 80S. A COLD FRONT WILL APPROACH NORTHERN OKLAHOMA LATE MONDAY INTO TUESDAY. THERE IS SOME UNCERTAINTY ON HOW FAR SOUTH THE FRONT WILL GO. NEVERTHELESS...THE FRONT AND NORTHWEST FLOW ALOFT SUGGEST AT LEAST LOW POPS ARE NEEDED LATE MONDAY THROUGH WEDNESDAY. MAHALE && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 62 76 61 65 / 20 10 30 40 HOBART OK 60 76 59 67 / 20 10 30 50 WICHITA FALLS TX 65 80 64 72 / 40 30 50 50 GAGE OK 53 73 51 58 / 0 10 30 50 PONCA CITY OK 57 75 55 63 / 0 10 20 40 DURANT OK 68 80 68 72 / 60 40 60 50 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 04/10
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
443 PM EDT WED SEP 10 2014 .SYNOPSIS... HIGH PRESSURE WEDGED ALONG AND EAST OF THE CENTRAL APPALACHIANS WILL SHIFT EAST TONIGHT. A STRONG COLD FRONT TRAILING A DEEP CYCLONE LIFTING THROUGH THE GREAT LAKES WILL MOVE ACROSS THE REGION ON THURSDAY. COOLER AND DRY WEATHER WILL FOLLOW BEHIND THE COLD FRONT ON FRIDAY. A SECONDARY FRONTAL SYSTEM WILL MOVE THROUGH THE AREA ON SATURDAY BEFORE HIGH PRESSURE RETURNS FAIR WEATHER ON SUNDAY. THE OVERALL PATTERN FAVORS BELOW NORMAL TEMPERATURES FROM SATURDAY INTO NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... EARLY EVENING VISIBLE STLT LOOP SHOWS BREAKING STRATUS ACROSS MUCH OF CENTRAL PA...WHILE CIRRUS IS ALEADY OVERSPREADING THE NW MTNS IN ADVANCE OF LL JET/WAA OVR THE GRT LKS. AN INTENSE SFC CYCLONE WILL TRACK NEWD ACRS THE GREAT LAKES THIS EVE AND CROSS THE ONT/QUE BORDER BTWN 06-12Z THU. THE TRAILING COLD FRONT SHOULD REACH A BUF-CMH LINE BY DAYBREAK THU WITH A STG 40-50KT SSWLY LLJ PROGGED AHEAD OF THE FRONT. THE LLJ WILL DRAW VERY HIGH MSTR CONTENT AIR INTO CENTRAL PA AHEAD OF THE FRONT WITH PWS AROUND 2 INCHES OR + 2 TO +3 SD ABOVE THE MEAN. THIS WILL RESULT IN VERY HIGH MSTR FLUX ANOMALIES AND SUPPORT CATG POPS OVER NWRN SXNS. IT WILL BE A WARM AND HUMID OVERNIGHT WITH TEMPS HOLDING IN THE MID TO UPPER 60S. IT WILL BE BREEZY OVER THE WRN HIGH TERRAIN AND ALLEGHENY RIDGES WITH GUSTS UP TO 30 MPH. FOLLOWED THE LATEST HRRR FOR PCPN TIMING INTO TONIGHT. THE STG WAA AND LLJ SUPPORTS A QUICKER EWD PROGRESSION OF LEADING EDGE LGT PCPN THRU THE UPPER OH VLY AND INTO WRN PA BTWN 00-06Z. CVRG OF SHOWER ACTIVITY AND SHALLOW/LOW-TOPPED CONVECTION SHOULD BE GREATEST OVER THE WRN 1/3 OF THE AREA OVERNIGHT AND INTO EARLY THU MORNING AHEAD OF THE COLD FRONT WITH LIMITED TS/LTG. HIGHEST QPF AMTS /0.25-0.50 INCH/ ARE ALSO FOCUSED OVER THIS AREA. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... COLD FRONT TRAILING DEEP SFC LOW MOVG THRU QUE WILL BE FOCUS FOR SHOWERS/TSTMS ON THU. THE MAIN CHANGE TO THE D2 FCST WAS FROM SPC WHICH LOWERED THE RISK FOR SEVERE STORMS BY CUTTING OUT THE SLGT RISK IN SCTNRL/SERN PA AND SHIFTING THE SEE TEXT/5% SVR PROBS SWD INTO LWX CWA. THIS MAKES SENSE GIVEN EARLY MORNING CLOUDS/RAIN RESULTING IN WEAK DIABATIC HEATING/INSTABILITY AND BEST FORCING/SHEAR BEING DISPLACED WELL TO THE NORTH. UPDATED HWO WILL BE ISSUED TO REFLECT THE LOWER SEVERE WX RISK...HOWEVER LCL GUSTY WINDS WILL REMAIN PSBL IN ANY STRONGER ORGANIZED TSTM CELLS/CLUSTERS. THE FRONT WILL EXIT THE SERN PRTNS OF THE CWA THU NGT WITH RAINS ENDING FROM NW TO SE. VERY HIGH PWS WOULD SUPPORT SOME EFFICIENT HEAVY DOWNPOURS BUT STORMS SHOULD BE MOVG SO HYDRO/FF CONCERNS ARE LOW ATTM. COOLER TEMPS THU NGT AS NLY WINDS BRING DRIER AIR INTO THE AREA BEHIND THE FIRST "FALL" FROPA. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... NOT A LOT OF CHANGE. MODELS STILL SHOW NORTHERN BRANCH OF JET MOVING THINGS ALONG. THUS DID EDGE TEMPS AND DEWPOINTS DOWN A LITTLE FOR FRIDAY. FRIDAY STILL LOOKS DRY. FOR SAT...STILL A CHC OF SHOWERS...GIVEN RATHER STRONG VORT MAX IN NORTHERN BRANCH. MID SHIFT HAD BROUGHT POPS UP SOME. I DID A LITTLE MORE. MOISTURE LIMITED...BUT DYNAMICS MAY TRIGGER AN ISOLATED THUNDERSTORM. LEFT SUNDAY INTO WED DRY. SOME HINTS OF A WEAK TROUGH OVER THE LAKES EARLY NEXT WEEK...BUT LEFT FCST DRY FOR NOW. && .AVIATION /21Z WEDNESDAY THROUGH MONDAY/... LOW CIGS HAVE BEEN RATHER PERSISTENT OVER THE CENTRAL 2/3RDS OF THE AIRSPACE AND GUID WAS TOO OPTIMISTIC ON AFTN IMPROVEMENT. LATEST OBS TRENDS SHOW CIGS SLOWLY LIFTING AOA LOW MVFR THRESHOLDS...WHILE CLOUDS CONTINUE TO ERODE ON THE WRN FLANKS OF THE LOW CLOUD DECK - WEST OF THE ALLEGHENY FRONT. UPSTREAM CUMULUS HAVE DEVELOPED IN THE PRE FRONTAL WARM SECTOR WERE THE SUN IS OUT...QUICKLY BECOMING OVERTOPPED BY THICKENING MID TO HIGH CLOUDS RACING EWD IN ASSOC WITH OH VLY CONVECTION. MAIN CHANGES FOR THE 18Z SCHEDULED TAFS WAS TO INCREASE TOA FOR SHRA INTO THE WRN AIRSPACE/ZOB SECTOR BASED ON COSPA/HRRR DATA. A VERY STRONG SOUTHERLY FLOW/LLJ AHEAD OF THE MAIN COLD FRONT WILL RESULT IN LLWS OVER WRN TERMINALS AFT 00Z...WHICH MAY NEED TO BE EXPANDED INTO THE CENTRAL SITES. TOUGH CALL FOR CIG TRENDS OVER CNTRL/ERN SXNS OVERNIGHT AS GUID WANTS TO LOWER CIGS DOWN TO IFR. FOR NOW WILL PLAY THINGS MORE OPTIMISTICALLY WITH INCR SLY GRADIENT FLOW SUGGESTIVE OF MORE MVFR TO LOW END VFR CIGS. FINALLY..THE LATEST DATA SHOWS MORE CLOUDS/PCPN SPREADING INTO THE AIRSPACE THRU EARLY TOMORROW. THIS SHOULD LIMIT HEATING AND ULTIMATELY THE RISK FOR STG TO SVR STORM DEVELOPMENT. LATER TAFS WILL NEED TO REFINE TIMING AND EXTENT OF PCPN CVRG. OUTLOOK... THU...SCT TO NMRS SHRA/TSTMS. COLD FROPA/WIND SHFT FM 180-270. AM LOW CIGS PSBL BCMG VFR. FRI...LOW CIGS PSBL EARLY OVR WRN 1/3...BCMG VFR. SAT...VFR/MVFR CIGS WITH SCT SHOWERS/TSTMS. SUN...PATCHY AM FOG...OTHERWISE VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...FITZGERALD/STEINBUGL SHORT TERM...STEINBUGL LONG TERM...MARTIN AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
356 PM EDT WED SEP 10 2014 .SYNOPSIS... HIGH PRESSURE WEDGED ALONG AND EAST OF THE CENTRAL APPALACHIANS WILL SHIFT EAST TONIGHT. A STRONG COLD FRONT TRAILING A DEEP CYCLONE LIFTING THROUGH THE GREAT LAKES WILL MOVE ACROSS THE REGION ON THURSDAY. COOLER AND DRY WEATHER WILL FOLLOW BEHIND THE COLD FRONT ON FRIDAY. A SECONDARY FRONTAL SYSTEM WILL MOVE THROUGH THE AREA ON SATURDAY BEFORE HIGH PRESSURE RETURNS FAIR WEATHER ON SUNDAY. THE OVERALL PATTERN FAVORS BELOW NORMAL TEMPERATURES FROM SATURDAY INTO NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 15-18Z VISIBLE STLT LOOP SHOWS PEAKS OF SUN ALONG THE ALLEGHENY FRONT INTO THE SCNTRL MTNS..WHILE MUCH OF THE INTERIOR CWA REMAINS M/CLOUDY FROM UNV TO SEG NWD TO THE NY BORDER. THE LATEST TRENDS SUGGEST BINOVC DEVELOPING LOCALLY THRU 20Z. AN INTENSE SFC CYCLONE WILL TRACK NEWD ACRS THE GREAT LAKES THIS EVE AND CROSS THE ONT/QUE BORDER BTWN 06-12Z THU. THE TRAILING COLD FRONT SHOULD REACH A BUF-CMH LINE BY DAYBREAK THU WITH A STG 40-50KT SSWLY LLJ PROGGED AHEAD OF THE FRONT. THE LLJ WILL DRAW VERY HIGH MSTR CONTENT AIR INTO CENTRAL PA AHEAD OF THE FRONT WITH PWS AROUND 2 INCHES OR + 2 TO +3 SD ABOVE THE MEAN. THIS WILL RESULT IN VERY HIGH MSTR FLUX ANOMALIES AND SUPPORT CATG POPS OVER NWRN SXNS. IT WILL BE A WARM AND HUMID OVERNIGHT WITH TEMPS HOLDING IN THE MID TO UPPER 60S. IT WILL BE BREEZY OVER THE WRN HIGH TERRAIN AND ALLEGHENY RIDGES WITH GUSTS UP TO 30 MPH. FOLLOWED THE LATEST HRRR FOR PCPN TIMING INTO TONIGHT. THE STG WAA AND LLJ SUPPORTS A QUICKER EWD PROGRESSION OF LEADING EDGE LGT PCPN THRU THE UPPER OH VLY AND INTO WRN PA BTWN 00-06Z. CVRG OF SHOWER ACTIVITY AND SHALLOW/LOW-TOPPED CONVECTION SHOULD GREATEST OVER THE WRN 1/3 OF THE AREA OVERNIGHT AND INTO EARLY THU MORNING AHEAD OF THE COLD FRONT WITH LIMITED TS/LTG. HIGHEST QPF AMTS /0.25-0.50 INCH/ ARE ALSO FOCUSED OVER THIS AREA. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... COLD FRONT TRAILING DEEP SFC LOW MOVG THRU QUE WILL BE FOCUS FOR SHOWERS/TSTMS ON THU. THE MAIN CHANGE TO THE D2 FCST WAS FROM SPC WHICH LOWERED THE RISK FOR SEVERE STORMS BY CUTTING OUT THE SLGT RISK IN SCTNRL/SERN PA AND SHIFTING THE SEE TEXT/5% SVR PROBS SWD INTO LWX CWA. THIS MAKES SENSE GIVEN EARLY MORNING CLOUDS/RAIN RESULTING IN WEAK DIABATIC HEATING/INSTABILITY AND BEST FORCING/SHEAR BEING DISPLACED WELL TO THE NORTH. UPDATED HWO WILL BE ISSUED TO REFLECT THE LOWER SEVERE WX RISK...HOWEVER LCL GUSTY WINDS WILL REMAIN PSBL IN ANY STRONGER ORGANIZED TSTM CELLS/CLUSTERS. THE FRONT WILL EXIT THE SERN PRTNS OF THE CWA THU NGT WITH RAINS ENDING FROM NW TO SE. VERY HIGH PWS WOULD SUPPORT SOME EFFICIENT HEAVY DOWNPOURS BUT STORMS SHOULD BE MOVG SO HYDRO/FF CONCERNS ARE LOW ATTM. COOLER TEMPS THU NGT AS NLY WINDS BRING DRIER AIR INTO THE AREA BEHIND THE FIRST "FALL" FROPA. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... NOT A LOT OF CHANGE. MODELS STILL SHOW NORTHERN BRANCH OF JET MOVING THINGS ALONG. THUS DID EDGE TEMPS AND DEWPOINTS DOWN A LITTLE FOR FRIDAY. FRIDAY STILL LOOKS DRY. FOR SAT...STILL A CHC OF SHOWERS...GIVEN RATHER STRONG VORT MAX IN NORTHERN BRANCH. MID SHIFT HAD BROUGHT POPS UP SOME. I DID A LITTLE MORE. MOISTURE LIMITED...BUT DYNAMICS MAY TRIGGER AN ISOLATED THUNDERSTORM. LEFT SUNDAY INTO WED DRY. SOME HINTS OF A WEAK TROUGH OVER THE LAKES EARLY NEXT WEEK...BUT LEFT FCST DRY FOR NOW. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... LOW CIGS HAVE BEEN RATHER PERSISTENT OVER THE CENTRAL 2/3RDS OF THE AIRSPACE AND GUID WAS TOO OPTIMISTIC ON AFTN IMPROVEMENT. LATEST OBS TRENDS SHOW CIGS SLOWLY LIFTING AOA LOW MVFR THRESHOLDS...WHILE CLOUDS CONTINUE TO ERODE ON THE WRN FLANKS OF THE LOW CLOUD DECK - WEST OF THE ALLEGHENY FRONT. UPSTREAM CUMULUS HAVE DEVELOPED IN THE PRE FRONTAL WARM SECTOR WERE THE SUN IS OUT...QUICKLY BECOMING OVERTOPPED BY THICKENING MID TO HIGH CLOUDS RACING EWD IN ASSOC WITH OH VLY CONVECTION. MAIN CHANGES FOR THE 18Z SCHEDULED TAFS WAS TO INCREASE TOA FOR SHRA INTO THE WRN AIRSPACE/ZOB SECTOR BASED ON COSPA/HRRR DATA. A VERY STRONG SOUTHERLY FLOW/LLJ AHEAD OF THE MAIN COLD FRONT WILL RESULT IN LLWS OVER WRN TERMINALS AFT 00Z...WHICH MAY NEED TO BE EXPANDED INTO THE CENTRAL SITES. TOUGH CALL FOR CIG TRENDS OVER CNTRL/ERN SXNS OVERNIGHT AS GUID WANTS TO LOWER CIGS DOWN TO IFR. FOR NOW WILL PLAY THINGS MORE OPTIMISTICALLY WITH INCR SLY GRADIENT FLOW SUGGESTIVE OF MORE MVFR TO LOW END VFR CIGS. FINALLY..THE LATEST DATA SHOWS MORE CLOUDS/PCPN SPREADING INTO THE AIRSPACE THRU EARLY TOMORROW. THIS SHOULD LIMIT HEATING AND ULTIMATELY THE RISK FOR STG TO SVR STORM DEVELOPMENT. LATER TAFS WILL NEED TO REFINE TIMING AND EXTENT OF PCPN CVRG. OUTLOOK... THU...SCT TO NMRS SHRA/TSTMS. COLD FROPA/WIND SHFT FM 180-270. AM LOW CIGS PSBL BCMG VFR. FRI...LOW CIGS PSBL EARLY OVR WRN 1/3...BCMG VFR. SAT...VFR/MVFR CIGS WITH SCT SHOWERS/TSTMS. SUN...PATCHY AM FOG...OTHERWISE VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...MARTIN AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
258 PM EDT WED SEP 10 2014 .SYNOPSIS... HIGH PRESSURE WEDGED ALONG AND EAST OF THE CENTRAL APPALACHIANS WILL SHIFT EAST TONIGHT. A STRONG COLD FRONT TRAILING A DEEP CYCLONE LIFTING THROUGH THE GREAT LAKES WILL MOVE ACROSS THE REGION ON THURSDAY. COOLER AND DRY WEATHER WILL FOLLOW BEHIND THE COLD FRONT ON FRIDAY. A SECONDARY FRONTAL SYSTEM WILL MOVE THROUGH THE AREA ON SATURDAY BEFORE HIGH PRESSURE RETURNS FAIR WEATHER ON SUNDAY. THE OVERALL PATTERN FAVORS BELOW NORMAL TEMPERATURES FROM SATURDAY INTO NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... 15-18Z VISIBLE STLT LOOP SHOWS PEAKS OF SUN ALONG THE ALLEGHENY FRONT INTO THE SCNTRL MTNS..WHILE MUCH OF THE INTERIOR CWA REMAINS M/CLOUDY FROM UNV TO SEG NWD TO THE NY BORDER. THE LATEST TRENDS SUGGEST BINOVC DEVELOPING LOCALLY THRU 20Z. AN INTENSE SFC CYCLONE WILL TRACK NEWD ACRS THE GREAT LAKES THIS EVE AND CROSS THE ONT/QUE BORDER BTWN 06-12Z THU. THE TRAILING COLD FRONT SHOULD REACH A BUF-CMH LINE BY DAYBREAK THU WITH A STG 40-50KT SSWLY LLJ PROGGED AHEAD OF THE FRONT. THE LLJ WILL DRAW VERY HIGH MSTR CONTENT AIR INTO CENTRAL PA AHEAD OF THE FRONT WITH PWS AROUND 2 INCHES OR + 2 TO +3 SD ABOVE THE MEAN. THIS WILL RESULT IN VERY HIGH MSTR FLUX ANOMALIES AND SUPPORT CATG POPS OVER NWRN SXNS. IT WILL BE A WARM AND HUMID OVERNIGHT WITH TEMPS HOLDING IN THE MID TO UPPER 60S. IT WILL BE BREEZY OVER THE WRN HIGH TERRAIN AND ALLEGHENY RIDGES WITH GUSTS UP TO 30 MPH. FOLLOWED THE LATEST HRRR FOR PCPN TIMING INTO TONIGHT. THE STG WAA AND LLJ SUPPORTS A QUICKER EWD PROGRESSION OF LEADING EDGE LGT PCPN THRU THE UPPER OH VLY AND INTO WRN PA BTWN 00-06Z. CVRG OF SHOWER ACTIVITY AND SHALLOW/LOW-TOPPED CONVECTION SHOULD GREATEST OVER THE WRN 1/3 OF THE AREA OVERNIGHT AND INTO EARLY THU MORNING AHEAD OF THE COLD FRONT WITH LIMITED TS/LTG. HIGHEST QPF AMTS /0.25-0.50 INCH/ ARE ALSO FOCUSED OVER THIS AREA. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... COLD FRONT TRAILING DEEP SFC LOW MOVG THRU QUE WILL BE FOCUS FOR SHOWERS/TSTMS ON THU. THE MAIN CHANGE TO THE D2 FCST WAS FROM SPC WHICH LOWERED THE RISK FOR SEVERE STORMS BY CUTTING OUT THE SLGT RISK IN SCTNRL/SERN PA AND SHIFTING THE SEE TEXT/5% SVR PROBS SWD INTO LWX CWA. THIS MAKES SENSE GIVEN EARLY MORNING CLOUDS/RAIN RESULTING IN WEAK DIABATIC HEATING/INSTABILITY AND BEST FORCING/SHEAR BEING DISPLACED WELL TO THE NORTH. UPDATED HWO WILL BE ISSUED TO REFLECT THE LOWER SEVERE WX RISK...HOWEVER LCL GUSTY WINDS WILL REMAIN PSBL IN ANY STRONGER ORGANIZED TSTM CELLS/CLUSTERS. THE FRONT WILL EXIT THE SERN PRTNS OF THE CWA THU NGT WITH RAINS ENDING FROM NW TO SE. VERY HIGH PWS WOULD SUPPORT SOME EFFICIENT HEAVY DOWNPOURS BUT STORMS SHOULD BE MOVG SO HYDRO/FF CONCERNS ARE LOW ATTM. COOLER TEMPS THU NGT AS NLY WINDS BRING DRIER AIR INTO THE AREA BEHIND THE FIRST "FALL" FROPA. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... FRIDAY STILL LOOKS DRY. DID UP MAX TEMPS SOME. FOR SAT...STILL A CHC OF SHOWERS...GIVEN RATHER STRONG VORT MAX IN NORTHERN BRANCH. TOOK OUT THUNDER. WENT WITH A DRY FCST AFT 04Z SUNDAY...AS HEIGHTS COME BACK UP TO 570 NEAR THE LOWER LAKES...TOO WARM FOR ANYTHING OFF THE LAKES...EVEN WITH W TO NW FLOW. SOME HINTS OF A WEAK TROUGH OVER THE LAKES EARLY NEXT WEEK...BUT LEFT FCST DRY FOR NOW. && .AVIATION /18Z WEDNESDAY THROUGH SUNDAY/... LOW CIGS HAVE BEEN RATHER PERSISTENT OVER THE CENTRAL 2/3RDS OF THE AIRSPACE AND GUID WAS TOO OPTIMISTIC ON AFTN IMPROVEMENT. LATEST OBS TRENDS SHOW CIGS SLOWLY LIFTING AOA LOW MVFR THRESHOLDS...WHILE CLOUDS CONTINUE TO ERODE ON THE WRN FLANKS OF THE LOW CLOUD DECK - WEST OF THE ALLEGHENY FRONT. UPSTREAM CUMULUS HAVE DEVELOPED IN THE PRE FRONTAL WARM SECTOR WERE THE SUN IS OUT...QUICKLY BECOMING OVERTOPPED BY THICKENING MID TO HIGH CLOUDS RACING EWD IN ASSOC WITH OH VLY CONVECTION. MAIN CHANGES FOR THE 18Z SCHEDULED TAFS WAS TO INCREASE TOA FOR SHRA INTO THE WRN AIRSPACE/ZOB SECTOR BASED ON COSPA/HRRR DATA. A VERY STRONG SOUTHERLY FLOW/LLJ AHEAD OF THE MAIN COLD FRONT WILL RESULT IN LLWS OVER WRN TERMINALS AFT 00Z...WHICH MAY NEED TO BE EXPANDED INTO THE CENTRAL SITES. TOUGH CALL FOR CIG TRENDS OVER CNTRL/ERN SXNS OVERNIGHT AS GUID WANTS TO LOWER CIGS DOWN TO IFR. FOR NOW WILL PLAY THINGS MORE OPTIMISTICALLY WITH INCR SLY GRADIENT FLOW SUGGESTIVE OF MORE MVFR TO LOW END VFR CIGS. FINALLY..THE LATEST DATA SHOWS MORE CLOUDS/PCPN SPREADING INTO THE AIRSPACE THRU EARLY TOMORROW. THIS SHOULD LIMIT HEATING AND ULTIMATELY THE RISK FOR STG TO SVR STORM DEVELOPMENT. LATER TAFS WILL NEED TO REFINE TIMING AND EXTENT OF PCPN CVRG. OUTLOOK... THU...SCT TO NMRS SHRA/TSTMS. COLD FROPA/WIND SHFT FM 180-270. AM LOW CIGS PSBL BCMG VFR. FRI...LOW CIGS PSBL EARLY OVR WRN 1/3...BCMG VFR. SAT...VFR/MVFR CIGS WITH SCT SHOWERS/TSTMS. SUN...PATCHY AM FOG...OTHERWISE VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...LAMBERT/MARTIN AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
305 PM CDT WED SEP 10 2014 .SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT CLOUDY AND COLD IS THE STORY ACROSS THE REGION THIS AFTERNOON. IN FACT...SOME LOCATIONS WILL LIKELY SET RECORDS FOR THE COLDEST HIGH TEMPERATURE EVER RECORDED ON THIS DATE. CWA IS CURRENTLY DRY BUT WATCHING THE BEGINNINGS OF THE NEXT SYSTEM MOVING ACROSS NORTHWEST SD. TREND FOR TONIGHT WILL BE FOR PRECIP TO MAINLY AFFECT WESTERN AND CENTRAL SD...AND MAY EVEN GET COLD ENOUGH LATE TONIGHT AND EARLY THURSDAY MORNING TO ALLOW FOR A RAIN/SNOW MIX ACROSS THE FAR NORTHWEST CWA. TARGET AREA FOR ACCUMULATING SNOW THOUGH STILL REMAINS OVER FAR WESTERN SD AND THE BLACK HILLS. WILL HAVE TO WATCH CLOUD COVER TRENDS OVERNIGHT ACROSS THE NORTHERN/NORTHEAST CWA AS CIGS HAVE THINNED AND HAVE EVEN REVEALED SOME HOLES. RAP MODEL 925-850MB RH SHOWS THIS DRIER AREA NICELY...AND BRINGS IN OVER THE NORTHERN COUNTIES LATER TONIGHT. IF ANY BREAKS OR THINNING OCCUR...TEMPS COULD FALL PRETTY NICELY. BUT OVERALL...THE ABUNDANCE OF MID AND HIGH CLOUDS WITH THE NEXT APPROACHING WAVE...AND THE OVERALL WINDS STAYING UP A TOUCH SHOULD PREVENT THE BOTTOM FROM FALLING OUT ON TEMPS. ATTENTION THEN TURNS TO THURSDAY NIGHT AND FRIDAY MORNING AND THE POTENTIAL FOR FROST. MODELS CONTINUE TO SHIFT PRECIP AND CLOUDS A BIT FURTHER SOUTH AND EAST DURING THIS TIME...A BIT QUICKER THAN PREVIOUS RUNS...AND THE PREVIOUSLY SLOWER EC IS NOW COMING AROUND TO THE FASTER SOLUTIONS OTHER MODELS HAVE BEEN SHOWING. THIS MEANS A BETTER POTENTIAL FOR FROST CONDITIONS AND TEMPS IN THE LOW TO MID 30S OVER A GOOD PORTION OF THE CWA. INSERTED FROST INTO THE GRIDS ALONG AND WEST OF THE JAMES VALLEY AND COULD VERY WELL BE HEADING TOWARDS A FROST ADVISORY AT SOME POINT. IT WILL ALL DEPEND ON HOW MUCH CLOUD COVER LINGERS OVER THE AREA...THE CLEARER THE SKIES THE BETTER THE TEMPS WILL FALL. FOR FRIDAY NIGHT AND SATURDAY...MODELS SEEM TO BE NUDGING THE HIGH CENTER TO THE EAST A TAD QUICKER. WHAT THIS MEANS IS THAT A SLIGHTLY STRONGER GRADIENT SETS UP FRIDAY NIGHT WITH SOUTH WINDS PICKING UP. WHETHER OR NOT THESE WINDS ARE STRONG ENOUGH ALONG AND EAST OF THE JAMES VALLEY TO PREVENT TEMPS FROM REACHING THE LOW TO MID 30S IS DOUBTFUL. WEST OF THERE...PROBABLY YES. CANNOT RULE OUT FROST FRIDAY NIGHT/SATURDAY MORNING EITHER...BUT BEST POTENTIAL HERE WILL BE ACROSS THE EASTERN CWA. .LONG TERM...SATURDAY THROUGH WEDNESDAY NOT MUCH CHANGE IN THE EXTENDED FROM 24 HOURS AGO. 12Z MODEL SOLUTIONS POINT TO A BIT OF WARMING ON SATURDAY OUT AHEAD OF AN APPROACHING COLD FRONT. ANOTHER SURFACE HIGH PRESSURE SYSTEM BUILDS DOWN FOR SUNDAY AND MONDAY...BUT THEN SHIFTS SOUTH AND EAST OF THE AREA...ALLOWING FOR RETURN FLOW WARMING WINDS TUESDAY AND WEDNESDAY. PRECIPITATION CHANCES REALLY ARE FEW AND FAR BETWEEN IN THE OUT PERIODS...WITH THE "BEST" CHANCES FOR A FEW RAIN SHOWERS SHOWING UP SUNDAY AFTERNOON/EVENING BEHIND THIS COLD FROPA. && .AVIATION... 18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS CONDITIONS ARE IMPROVING ACROSS THE REGION. KMBG HAS BEGUN BOUNCING IN AND OUT OF VFR/MVFR...AND KATY IS SLOWLY TRENDING TOWARD AN MVFR CIG. KPIR/KABR REMAIN MVFR AS WELL...BUT SATELLITE TRENDS AND SHORT RANGE RAPID REFRESH MODEL OUTPUT ALL POINT TO VFR RETURNING TO THE REGION AS THE PREVAILING CONDITION BY 00Z THIS EVENING AT KABR/KPIR AND KMBG...WITH KATY FOLLOWING BY 06Z. THE RAPID REFRESH MODEL IS ALSO TAKING PRECIP CHANCES SOUTH LATER THIS EVENING...WITH THE BULK OF ANY PRECIP CHANCES WITH THIS NEXT LITTLE WAVE OF LOW PRESSURE RE-ALIGNING TOWARD THE KPIR AREA LATER AT OR AFTER MIDNIGHT. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ SHORT TERM...TMT LONG TERM...DORN AVIATION...DORN WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
115 PM CDT WED SEP 10 2014 .UPDATE... DECIDED TO PULL THE TRIGGER ON LOWERING THE MAX T GRID ACROSS THE BOARD FOR THIS AFTERNOON. HOURLY FORECAST WAS TRENDING ABOUT 2-4 DEGREES BELOW REALITY AND WITH THE SKIES MOSTLY CLOUD COVERED AND SHOULD REMAIN THAT WAY...DONT THINK WE WILL HIT THE PREVIOUSLY ADVERTISED HIGHS. ALSO RAISED POPS IN THE WEST DUE TO THE ISOLATED SHOWERS POPPING UP WEST OF I65. WITH IT BEING ONLY 18Z AND A BIT MORE CONVECTIVE POTENTIAL IS EXPECTED WITH A VERY MOIST ATMOSPHERE...THINK THIS IS PROBABLY A SAFE BET. && .PREV DISCUSSION... /ISSUED 1204 PM CDT WED SEP 10 2014/ AVIATION UPDATE...FOR 18Z TAF PACKAGE... MVFR CONDITIONS CONTINUE TO PERSIST FOR KCKV AND KBNA. SHOULD SEE A BRIEF IMPROVEMENT BUT PROBABLY NOT UNTIL AFTER DARK. AN APPROACHING COLD FRONT WILL CONTINUE TO INCREASE CLOUD COVERAGE ALTHOUGH A CEILINGS SHOULD RISE TO VFR HEIGHTS BRIEFLY BEFORE THE RAIN ARRIVES. INCLUDED -SHRA MENTION BEGINNING JUST BEFORE MIDNIGHT FOR KCKV. ACTIVITY SHOULD PROGRESS EASTWARD SLOWLY AND IMPACT KBNA BY JUST BEFORE DAWN. LEFT RAIN OUT OF KCSV FOR NOW BUT DID MENTION MVFR BR POSSIBILITIES IN THE EARLY MORNING THERE. PREV DISCUSSION... /ISSUED 1141 AM CDT WED SEP 10 2014/ UPDATE... WITH THE APPROACHING COLD FRONT BRINGING A BROKEN DECK OF HIGH CLOUDS FOR MUCH OF THE WESTERN HALF OF THE CWA...AND BOUNDARY LAYER CONVECTIVE CU BEGINNING TO FORM AS WELL...OPTED TO INCREASE THE SKY GRIDS TO MOSTLY CLOUDY WORDING THROUGH THE EVENING. VIS SATELLITE IS SHOWING AN AREA OF CONFLUENCE IN NORTHERN MS AND WESTERN TN. THIS IS JUST AHEAD OF THE CURRENT ACTIVITY APPROACHING THE MO BOOTHEEL WHICH MAY PROVIDE ENOUGH BOUNDARY LAYER CONVERGENCE TO PRODUCE ISOLATED SHOWER AND STORM DEVELOPMENT OVER THE NEXT COUPLE HOURS. HRRR SEEMS TO AGREE BUT IS A BIT EARLY ON THE DEVELOPMENT. SOME OF THOSE SHOWERS MAY IMPACT OUR CWA WEST OF THE I65 CORRIDOR MAINLY. WE CURRENTLY HAVE SLIGHT CHANCE POPS IN THE GRIDS FOR THE AFTERNOON AND WITH THE EXPECTED ISOLATED NATURE OF THE DEVELOPMENT...DONT SEE A REASON TO INCREASE TO CHC POPS JUST YET. MAY NEED ANOTHER UPDATE IF THINGS ARE A BIT MORE SUBSTANTIAL. ALSO KEEPING AN EYE ON THE MAX T AS CLOUDS CONTINUE TO LIMIT WARMING...WE ARE ABOUT 2-3 DEGREES BELOW THE FORECAST HOURLY TEMPS ACROSS THE BOARD SO IF THAT PERSISTS...MAY NEED TO LOWER THE MAX T GRID AS WELL. WILL REEVALUATE AT 18Z. PREV DISCUSSION... /ISSUED 625 AM CDT WED SEP 10 2014/ AVIATION...BNA/CKV/CSV...LOW CLOUDS AT CSV SHOULD GIVE WAY BY 15Z OR SO. LOOK FOR WINDS TO INCREASE THIS MORNING AHEAD OF A SLOW- MOVING COLD FRONT. VFR CIGS WILL COVER MIDDLE TENNESSEE MOST OF TODAY AND TONIGHT WITH SHRA AND POSSIBLE TSRA MOVING INTO NW MIDDLE TENNESSEE OVERNIGHT. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ TB12
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1204 PM CDT WED SEP 10 2014 .AVIATION UPDATE...FOR 18Z TAF PACKAGE... MVFR CONDITIONS CONTINUE TO PERSIST FOR KCKV AND KBNA. SHOULD SEE A BRIEF IMPROVEMENT BUT PROBABLY NOT UNTIL AFTER DARK. AN APPROACHING COLD FRONT WILL CONTINUE TO INCREASE CLOUD COVERAGE ALTHOUGH A CEILINGS SHOULD RISE TO VFR HEIGHTS BRIEFLY BEFORE THE RAIN ARRIVES. INCLUDED -SHRA MENTION BEGINNING JUST BEFORE MIDNIGHT FOR KCKV. ACTIVITY SHOULD PROGRESS EASTWARD SLOWLY AND IMPACT KBNA BY JUST BEFORE DAWN. LEFT RAIN OUT OF KCSV FOR NOW BUT DID MENTION MVFR BR POSSIBILITIES IN THE EARLY MORNING THERE. && .PREV DISCUSSION... /ISSUED 1141 AM CDT WED SEP 10 2014/ UPDATE... WITH THE APPROACHING COLD FRONT BRINGING A BROKEN DECK OF HIGH CLOUDS FOR MUCH OF THE WESTERN HALF OF THE CWA...AND BOUNDARY LAYER CONVECTIVE CU BEGINNING TO FORM AS WELL...OPTED TO INCREASE THE SKY GRIDS TO MOSTLY CLOUDY WORDING THROUGH THE EVENING. VIS SATELLITE IS SHOWING AN AREA OF CONFLUENCE IN NORTHERN MS AND WESTERN TN. THIS IS JUST AHEAD OF THE CURRENT ACTIVITY APPROACHING THE MO BOOTHEEL WHICH MAY PROVIDE ENOUGH BOUNDARY LAYER CONVERGENCE TO PRODUCE ISOLATED SHOWER AND STORM DEVELOPMENT OVER THE NEXT COUPLE HOURS. HRRR SEEMS TO AGREE BUT IS A BIT EARLY ON THE DEVELOPMENT. SOME OF THOSE SHOWERS MAY IMPACT OUR CWA WEST OF THE I65 CORRIDOR MAINLY. WE CURRENTLY HAVE SLIGHT CHANCE POPS IN THE GRIDS FOR THE AFTERNOON AND WITH THE EXPECTED ISOLATED NATURE OF THE DEVELOPMENT...DONT SEE A REASON TO INCREASE TO CHC POPS JUST YET. MAY NEED ANOTHER UPDATE IF THINGS ARE A BIT MORE SUBSTANTIAL. ALSO KEEPING AN EYE ON THE MAX T AS CLOUDS CONTINUE TO LIMIT WARMING...WE ARE ABOUT 2-3 DEGREES BELOW THE FORECAST HOURLY TEMPS ACROSS THE BOARD SO IF THAT PERSISTS...MAY NEED TO LOWER THE MAX T GRID AS WELL. WILL REEVALUATE AT 18Z. PREV DISCUSSION... /ISSUED 625 AM CDT WED SEP 10 2014/ AVIATION...BNA/CKV/CSV...LOW CLOUDS AT CSV SHOULD GIVE WAY BY 15Z OR SO. LOOK FOR WINDS TO INCREASE THIS MORNING AHEAD OF A SLOW- MOVING COLD FRONT. VFR CIGS WILL COVER MIDDLE TENNESSEE MOST OF TODAY AND TONIGHT WITH SHRA AND POSSIBLE TSRA MOVING INTO NW MIDDLE TENNESSEE OVERNIGHT. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ TB12
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1141 AM CDT WED SEP 10 2014 .UPDATE... WITH THE APPROACHING COLD FRONT BRINGING A BROKEN DECK OF HIGH CLOUDS FOR MUCH OF THE WESTERN HALF OF THE CWA...AND BOUNDARY LAYER CONVECTIVE CU BEGINNING TO FORM AS WELL...OPTED TO INCREASE THE SKY GRIDS TO MOSTLY CLOUDY WORDING THROUGH THE EVENING. VIS SATELLITE IS SHOWING AN AREA OF CONFLUENCE IN NORTHERN MS AND WESTERN TN. THIS IS JUST AHEAD OF THE CURRENT ACTIVITY APPROACHING THE MO BOOTHEEL WHICH MAY PROVIDE ENOUGH BOUNDARY LAYER CONVERGENCE TO PRODUCE ISOLATED SHOWER AND STORM DEVELOPMENT OVER THE NEXT COUPLE HOURS. HRRR SEEMS TO AGREE BUT IS A BIT EARLY ON THE DEVELOPMENT. SOME OF THOSE SHOWERS MAY IMPACT OUR CWA WEST OF THE I65 CORRIDOR MAINLY. WE CURRENTLY HAVE SLIGHT CHANCE POPS IN THE GRIDS FOR THE AFTERNOON AND WITH THE EXPECTED ISOLATED NATURE OF THE DEVELOPMENT...DONT SEE A REASON TO INCREASE TO CHC POPS JUST YET. MAY NEED ANOTHER UPDATE IF THINGS ARE A BIT MORE SUBSTANTIAL. ALSO KEEPING AN EYE ON THE MAX T AS CLOUDS CONTINUE TO LIMIT WARMING...WE ARE ABOUT 2-3 DEGREES BELOW THE FORECAST HOURLY TEMPS ACROSS THE BOARD SO IF THAT PERSISTS...MAY NEED TO LOWER THE MAX T GRID AS WELL. WILL REEVALUATE AT 18Z. && .PREV DISCUSSION... /ISSUED 625 AM CDT WED SEP 10 2014/ AVIATION...BNA/CKV/CSV...LOW CLOUDS AT CSV SHOULD GIVE WAY BY 15Z OR SO. LOOK FOR WINDS TO INCREASE THIS MORNING AHEAD OF A SLOW- MOVING COLD FRONT. VFR CIGS WILL COVER MIDDLE TENNESSEE MOST OF TODAY AND TONIGHT WITH SHRA AND POSSIBLE TSRA MOVING INTO NW MIDDLE TENNESSEE OVERNIGHT. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ TB12
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
113 PM EDT WED SEP 10 2014 .SYNOPSIS... LOW PRESSURE PASSING WELL TO THE NORTH WILL DRAG A TRAILING COLD FRONT TOWARD THE REGION TONIGHT...REACHING THE WESTERN SLOPES OF THE APPALACHIANS BY LATER THURSDAY. THE FRONT IS EXPECTED TO STALL OVER THE CAROLINAS FRIDAY AND THEN MEANDER JUST SOUTH OF THE AREA OVER THE WEEKEND. WEAK LOW PRESSURE RIDING ALONG THE BOUNDARY MAY KEEP PERIODS OF SHOWERS GOING INTO EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1113 AM EDT WEDNESDAY... UPDATING TO LOWER TEMPS A BIT AND HOLD CLOUDS LONGER ESPCLY ALONG THE BLUE RIDGE WHERE LOW CLOUDS REMAIN PERSISTENT WITH EVEN SOME SPOTTY -RA MIXED IN GIVEN THE WEAK LOW LEVEL VEERING PROFILE OFF MORNING RAOBS. ALSO WITH SO MUCH LINGERING MOISTURE STUCK BENEATH MULTIPLE INVERSIONS ALOFT OFF 12Z SOUNDINGS APPEARS WILL BE TOUGH TO GET A QUICK EROSION OF THE CANOPY WITHOUT IT FILLING BACK IN ESPCLY EARLY ON. EXPECT ONCE THE FLOW TURNS MORE SOUTH/SW LATER ON AND MIXING INCREASES WILL SEE SOME DRIER AIR ALOFT MIX DOWN BUT MAY BE LATE BEFORE THE EASTERN SLOPES OF THE BLUE RIDGE SEE A LOT OF SUN. TEMPS LIKELY TO JUMP WHERE DO GET SOME SUSTAINED BREAKS BUT FOR NOW BASED ON LATEST TRENDS AND LAV MOS...THINK HIGHS MAY REMAIN IN THE 70S EXCEPT FOR THE FAR EAST/SE AND WESTERN PERIMETER COUNTIES. ISOLATED WESTERN POPS THIS AFTERNOON STILL APPEAR OK WITH THE BRIEF SHOTGUN PATTERN SUGGESTED BY THE LATEST HRRR BUT THIS BASED ON SOME INSTABILITY PER HEATING WHICH MAY ONLY OCCUR ALONG THE I-77 CORRIDOR AT THIS POINT. PREVIOUS UPDATE AS OF 925 AM EDT WEDNESDAY... ADDED SLIGHT CHANCE POPS ALONG THE BLUE RIDGE UP TO ROANOKE AS SURFACE OBS AND WEATHER SPOTTERS HAVE CONFIRMED SOME LIGHT DRIZZLE THIS MORNING. TWEAKED THE SKY GRIDS OUT WEST WHERE THERE HAS BEEN SOME CLEARING. ALSO ADJUSTED THE NEAR TERM TEMPS. ALL OTHER FORECAST DETAILS FROM THE PREVIOUS DISCUSSION REMAIN ON TRACK. PREVIOUS DISCUSSION AS OF 430 AM EDT WEDNESDAY... STARTING OFF WITH LOTS OF CLOUD COVER THIS MORNING...COURTESY OF LINGERING MOISTURE BANKED UP AGAINST THE EAST SIDE OF THE MOUNTAINS. THE EASTERLY WIND WHICH HAS BEEN KEEPING THE CLOUDS PINNED ACROSS THE AREA WILL WEAKEN TODAY AS FLOW BEGINS TO TREND MORE SOUTHERLY PER APPROACH OF FRONTAL SYSTEM OVER THE MIDDLE PART OF THE COUNTRY. AS OF 4AM...CYCLOGENESIS WAS TAKING PLACE OVER THE MIDDLE PART OF THE COUNTRY WITH LOW PRESSURE DEVELOPING NEAR TOPEKA KANSAS. THIS AREA OF LOW PRESSURE IS FORECAST TO STRENGTHEN TODAY PER STRONG DYNAMICS ALOFT ASSOCIATED WITH A SHORT WAVE TROUGH EXITING THE ROCKIES. THE DEEPENING LOW...10 MB PRESSURE FALL OVER THE NXT 12 HOURS...IS PROGGED TO MOVE NORTHEAST INTO THE GREAT LAKES...THE TRAILING COLD FRONT SLICING SOUTH THROUGH MISSOURI-TEXAS. AHEAD OF THE FRONT...WINDS WILL BE SOUTHWESTERLY THROUGH THE TENNESSEE AND OHIO VALLEYS...WARM AIR ADVECTION TAKING PLACE UPSTREAM OF OUR FORECAST AREA...AND EVENTUALLY INCLUDING OUR FORECAST AREA LATER TODAY AND TONIGHT. AS WARM AIR ADVECTION INCREASES FROM THE SOUTHWEST LATER TODAY...EXPECT CLOUD COVER CURRENTLY OVER OUR FORECAST AREA TO MIX OUT WITH INCREASING AMOUNTS OF SUN. SUNNY BREAKS WILL LIKELY BEGIN IN THE WESTERN PART OF THE CWA FIRST...THEN SPREAD EAST. MORE SUN MEANS WARMER TEMPERATURES...MODEL MOS SUGGESTING WE TEST 80 TODAY WITH A TEMPERATURE RANGE OF 76 TO 83. MILD TEMPERATURES ARE LIKELY TONIGHT...SOUTHWEST WINDS CONTINUING TO PROMOTE WARM AIR ADVECTION...LOWS IN THE 60S. NOT MUCH THREAT FOR PRECIP TODAY OR TONIGHT. MODEL SOUNDINGS INDICATE CAPE VALUES POTENTIALLY REACHING 500 J/KG IN THE MOUNTAINS TODAY. THIS MAY SUPPORT AN ISOLATED SHOWER OR TWO...BUT NOT MUCH MORE THAN THAT. BETTER CHANCE FOR PRECIP WILL COME WITH THE FRONTAL PASSAGE LATER THURSDAY. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... AS OF 400 AM EDT WEDNESDAY... LOOK FOR THURSDAY TO BE THE WARMEST DAY OF THE WEEK AS DEEP SOUTHWESTERLY FLOW BECOMES ESTABLISHED AHEAD OF A STRONG COLD FRONT APPROACHING FROM THE GREAT LAKES REGION. THE SOUTHWESTERLY WINDS WILL DRAW VERY WARM GULF MOISTURE NORTHWARD ALONG THE APPALACHIAN CHAIN...WHICH WILL HELP AFTERNOON HIGHS CLIMB INTO THE UPPER 70S/LOW 80S ACROSS THE MOUNTAINS...WHILE THE PIEDMONT WILL REACH INTO THE MID 80S TO AROUND 90 IN THE SOUTHSIDE. RAIN CHANCES WILL INCREASE DRASTICALLY DURING THE AFTERNOON AS THE FRONT CROSSES THE OHIO RIVER...WITH SHOWERS AND THUNDERSTORMS BECOMING WIDESPREAD ACROSS MOST OF THE AREA BY SUNSET. STORM PREDICTION CENTER HAS MUCH OF OUR FORECAST REGION UNDER A SLIGHT CHANCE FOR SEVERE THUNDERSTORMS...SO WILL BE ON THE LOOKOUT FOR A FEW STORMS PACKING GUSTY WINDS DURING THE EVENING...MAINLY NORTH OF HIGHWAY 460...AS THE STRONGER DOWNDRAFTS TRY TO PULL THE 25KT-30KT 850MB WINDS DOWN TO THE SURFACE. BELIEVE THERE WILL ALSO BE A CHANCE FOR LOCALLY HEAVY RAIN ACROSS THE MOUNTAINS AS GULF MOISTURE POOLING AHEAD OF THE FRONT PUSHES PRECIPITABLE WATER IN THE BALLPARK OF 2 INCHES. THE COLD FRONT WILL CONTINUE ITS SOUTHWARD PUSH THURSDAY NIGHT... BEFORE STALLING ACROSS CENTRAL NORTH CAROLINA JUST SOUTH OF OUR AREA ON FRIDAY AS IT RUNS INTO UPPER LEVEL RIDGING ACROSS THE SOUTHEAST STATES. MODELS ARE COMING INTO BETTER AGREEMENT THAT...DESPITE THE FRONTAL PASSAGE...DEWPOINTS DO NOT DROP OFF ALL THAT MUCH FOR OUR AREA. AS SUCH...EXPECT THAT THERE WILL BE ENOUGH LOW LEVEL MOISTURE LEFT OVER TO SUPPORT SCATTERED SHOWER ACTIVITY ACROSS THE MOUNTAINS AND THE PIEDMONT SOUTH OF HIGHWAY 460 THROUGH THE AFTERNOON AND EVENING. DRIER HIGH PRESSURE WILL BE WEDGING SOUTHWARD ACROSS THE PIEDMONT FURTHER NORTH. HIGHS FOR FRIDAY WILL BE COOLER...MAINLY IN THE 70S MOST LOCATIONS. SHOWER ACTIVITY WILL INCREASE AGAIN ON SATURDAY AS A WAVE OF LOW PRESSURE DEVELOPS ALONG THE FRONT. SURFACE HIGH PRESSURE BANKED AGAINST THE EASTERN FACE OF THE APPALACHIANS WILL PROVIDE ENOUGH STABILITY TO LIMIT RAINFALL TO SHOWER ACTIVITY FOR MOST OF THE AREA...ALTHOUGH AN ISOLATED THUNDERSTORM MAY DEVELOP ACROSS THE MOUNTAIN EMPIRE...AN AREA REMOVED FROM THE INFLUENCE OF THE HIGH. AT ANY RATE...THE WAVE WILL SHIFT RAPIDLY TO THE NORTH ON SATURDAY... DRAGGING A SECONDARY COLD FRONT ACROSS OUR AREA DURING THE EVENING. CANADIAN HIGH PRESSURE BUILDING IN BEHIND THE COLD FRONT WILL BE THE COOLEST AIR WE HAVE SEEN IN SEVERAL MONTHS...A DEFINITE SIGNAL THAT AUTUMN IS NOT TOO FAR INTO THE FUTURE. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 100 PM EDT TUESDAY... FORECAST REMAINS RATHER LOW CONFIDENCE FOR SUNDAY INTO TUESDAY GIVEN WEST/SW FLOW ALOFT BETWEEN AN UPPER TROUGH TO THE NW AND THE RESIDUAL AXIS OF DEEPER MOISTURE ALONG THE COAST. LATEST GUIDANCE STILL RATHER MIXED ON DEGREE OF MOISTURE GETTING PULLED BACK INLAND/NORTH AHEAD OF THE MAIN TROUGH AS APPEARS SOME SORT OF LEFTOVER DEFORMATION AXIS MAY LINGER WITH THE COASTAL LOW. THUS KEPT SOME LOW POPS IN SOUTH/EAST ESPCLY SUNDAY/SUNDAY NIGHT THEN DECREASING MONDAY FOR NOW. APPEARS DRIER AIR WITH THE STRONGER SURFACE HIGH BUILDING IN FROM THE NW WILL FINALLY OCCUR BY TUESDAY BUT EVEN THEN CLOUDS/SHOWERS MAY LINGER/RETURN WITH YET ANOTHER WAVE PASSING. TEMPS TO COOL BELOW NORMAL THROUGH THE PERIOD WITH MAINLY 60S MOUNTAINS AND LOW 70S EAST FOR HIGHS...AND 50S WEST 60S PIEDMONT FOR LOWS PENDING CLOUD COVER WHICH COULD MAKE HIGHS EVEN COOLER. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 1255 PM EDT WEDNESDAY... STUBBORN LOW LEVEL CLOUDS REMAIN SLOW TO ERODE EARLY THIS AFTERNOON WITH MOSTLY MVFR CIGS IN PLACE. STILL EXPECTING A GRADUAL IMPROVEMENT TO VFR BASES AS WELL AS A REDUCTION IN CLOUD COVER THROUGH THE REST OF THE AFTERNOON/EVENING AS WINDS BECOME MORE SOUTHERLY. HOWEVER MAY STILL TAKE UNTIL LATE IN THE DAY FOR LOWER CIGS AT KBCB/KROA TO LIFT INTO VFR RANGE. A STRONG LOW PRESSURE SYSTEM PASSING WELL TO THE NORTH WILL PROPEL A TRAILING COLD FRONT TOWARD THE AREA LATE TONIGHT INTO THURSDAY. PRE-FRONTAL SHOWERS/STORMS AHEAD OF THE FRONT MAY APPROACH THE FAR NORTHWESTERN LOCATIONS EARLY THURSDAY WITH INCREASING COVERAGE FROM NW TO SE DURING THE DAY. AS DEEPER MOISTURE RETURNS LATER TONIGHT...LIKELY TO SEE SOME LOW CLOUDS RETURN WEST WHILE LIGHT WINDS MAY PROMOTE RETURN OF THE RESIDUAL WEDGE AND LOW CLOUDS BLUE RIDGE LATE TONIGHT. WONT GO QUITE AS PESSIMISTIC AS MOST GUIDANCE GIVEN WEAK SOUTHERLY FLOW BUT INCLUDING SOME MVFR CIGS FROM THE BLUE RIDGE EAST ALONG WITH BRIEF DENSE FOG THAT MAY BRING PERIODS OF MVFR/IFR BY DAYBREAK THURSDAY. ANY LOW CLOUDS/FOG SHOULD FINALLY MIX OUT WITH INCREASING SW FLOW THURSDAY MORNING OVER THE EAST...WHILE CIGS LOWER OVER THE WEST WITH LEFTOVER EARLIER SHRA PERHAPS REACHING KLWB/KBLF LATE MORNING/EARLY AFTERNOON THURSDAY. HOWEVER APPEARS BEST SHOT AT SEEING BANDS/CLUSTERS OF CONVECTION WONT OCCUR UNTIL MID/LATE AFTERNOON THURSDAY AND BEYOND THE TIME OF THE VALID TAF PERIOD. WEST/SW WINDS SHOULD TURN A BIT GUSTY AS WELL AHEAD OF THE FRONT THURSDAY AFTERNOON WITH 10-20 KTS LIKELY AND STRONGER CLOSER TO ANY STORMS. EXTENDED DISCUSSION... FROPA IS EXPECTED THURSDAY NIGHT. THIS FRONTAL PASSAGE WILL NOT BE A CLEAN SWEEP OF AIRMASSES...THE MAJORITY OF THE MODELS INDICATING THE FRONT WILL STALL OVER THE CAROLINAS FRIDAY...FOLLOWED BY DEVELOPMENT OF LOW PRESSURE ALONG THE FRONT FRIDAY NIGHT...TRACKING NORTHEAST THROUGH THE REGION SATURDAY. STILL APPEARS THAT AN EXTENDED PERIOD OF MVFR...POSSIBLY IFR...WILL EXIST FRIDAY NIGHT INTO SATURDAY. LOW CONFIDENCE FORECAST FOR SUNDAY WITH MODELS SHOWING LOW LEVEL MOISTURE LINGERING ALONG WITH SPOTTY SHOWERS AS COMPLEX LOW PRESSURE DEVELOPS OVER THE REGION SO APPEARS OVERALL MVRF TO PERSIST INTO SUNDAY NIGHT AT THIS POINT. LOW CLOUDS MAY ERODE ON MONDAY BUT WITH LEFTOVER MOISTURE EXPECTING POTENTIAL FOR MVFR AT TIMES IN SPOTTY SHOWERS MONDAY AFTERNOON. OTRW SLOW IMPROVEMENT TO VFR FOR EARLY NEXT WEEK. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH NEAR TERM...CF/JH/PM SHORT TERM...NF LONG TERM...JH AVIATION...JH/PM
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND THURSDAY ISSUED AT 242 PM CDT WED SEP 10 2014 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG LOW PRESSURE SYSTEM TRACKING NORTHEAST TOWARDS MANITOWOC WHILE A POTENT COLD FRONT IS DROPPING SOUTHEAST FROM THE BAY OF GREEN BAY TO JUST WEST OF OSHKOSH. MOST OF THE HEAVIER RAINFALL HAS EXITED THE REGION TO THE NORTHEAST EXCEPT FOR FAR WESTERN ONEIDA AND VILAS COUNTIES. AREAS OF DRIZZLE OR VERY LIGHT RAIN WILL GRADUALLY DIMINISH THROUGH THE REST OF THE AFTERNOON AS THE CYCLONE EXITS THE REGION. OBSERVATIONS INDICATE A WIDESPREAD 1.5 TO 2.5 INCHES OF RAIN OVER NORTH-CENTRAL WISCONSIN FOR A STORM TOTAL. AREA RIVERS SEEM TO BE HOLDING UP WELL AND HAVE RECEIVED NO REPORTS OF FLOODING SO FAR. WILL LET THE FLOOD WATCH EXPIRE WITH THIS FORECAST ISSUANCE. GUSTY NORTHWEST WINDS ARE USHERING IN THE FIRST TASTE OF FALL BEHIND THE COLD FRONT. TEMPERATURES ARE FALLING INTO THE 40S AND 50S BEHIND THE FRONT...WHILE READINGS REMAIN IN THE 60S AND 70S AHEAD OF THE FRONT. TIMING THE END OF THE PRECIP...TEMPS...AND MARINE HEADLINES ARE THE MAIN FORECAST CONCERNS. TONIGHT...LOW PRESSURE WILL CONTINUE TO MOVE TO THE NORTHEAST INTO EASTERN ONTARIO AND WESTERN QUEBEC WHILE THE STRONG COLD FRONT MOVES EAST ACROSS THE LOWER PENINSULA OF MICHIGAN. BEHIND THE FRONT...GUSTY NORTHWEST WINDS WILL USHER IN A MIGHTY CHILLY AIRMASS FOR THIS TIME OF THE YEAR. WITH LOW INVERSION HEIGHTS OF AROUND 875MB...THE AIRMASS WILL BE PLENTY COLD ENOUGH TO SUPPORT LAKE EFFECT RAIN SHOWERS OFF LAKE SUPERIOR...WHICH WILL LIKELY JUST IMPACT VILAS COUNTY AS WIND TRAJECTORIES ARE TOO NORTHERLY FOR A DIRECT HIT. PLENTY OF LOW STRATUS UPSTREAM BENEATH THIS INVERSION...AND WITH MOISTURE FLUXES OFF LAKE SUPERIOR COMBINED WITH THERMAL TROUGHING...HAVE A TOUGH TIME SEEING ANY SORT OF CLEARING TAKING PLACE. PERHAPS A FEW HOLES IN THE OVERCAST IN THE DOWNSLOPING AREAS OF NORTHEAST WISCONSIN. LOWS FALLING INTO THE UPPER 30S NORTH TO UPPER 40S SOUTHEAST. THURSDAY...850MB TEMPERATURES CONTINUE TO FALL AS CANADIAN HIGH PRESSURE BUILDS TOWARDS THE REGION. THE INVERSION WILL REMAIN STOUT ABOVE STEEP LOW LEVEL LAPSE RATES. AS A RESULT...CLOUDY CONDITIONS IN THE MORNING WILL BE SLOW TO BREAK UP...ESPECIALLY WITH MID-LEVEL CLOUDS ARRIVING IN THE AFTERNOON. SO EXPECT SKY CONDITIONS TO REMAIN AT LEAST PARTLY SUNNY OR MOSTLY CLOUDY THROUGH THE DAY. HIGHS RANGING FROM THE UPPER 40S NORTH TO MIDDLE 50S SOUTH. .LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY ISSUED AT 242 PM CDT WED SEP 10 2014 LARGE SURFACE HIGH SHOULD COVER THE NORTHERN AND CENTRAL PLAINS ALL THE WAY EAST TO THE GREAT LAKES AND NORTHERN OHIO VALLEY THURSDAY NIGHT THROUGH FRIDAY EVENING. WHILE THIS WOULD NORMALLY RESULT IN A DRY FORECAST AND CLEAR SKIES THERE IS A SHARP UPPER LEVEL TROUGH THAT WILL BE MOVING ACROSS WISCONSIN FRIDAY AND FRIDAY EVENING THAT SHOULD BE STRONG ENOUGH TO PRODUCE SOME LIGHT RAIN DESPITE SURFACE HIGH PRESSURE AND DRY AIR IN THE LOW LEVELS. THE CLOUDS AND LIGHT RAIN SHOULD KEEP HIGH TEMPERATURES LOWER THAN MOS GUIDANCE FRIDAY SO WENT ABOUT 3 DEGREES LOWER IN MOST PLACES. LOW TEMPERATURES SATURDAY MORNING WILL DEPEND ON HOW QUICKLY THE UPPER SYSTEM EXITS FRIDAY NIGHT AND HOW QUICKLY SKIES CLEAR. THE ECMWF IS SLOWER THAN THE GFS AND ITS SOLUTION WOULD KEEP CLOUDS ALL NIGHT AND HOLD TEMPERATES UP. WE ARE SIDING WITH THE QUICKER GFS AND THUS WENT LOWER THAN GUIDANCE FOR LOWS FRIDAY NIGHT. NICE WEATHER EXPECTED SATURDAY THROUGH SUNDAY WITH A SLIGHT CHANCE OF SHOWERS SUNDAY EVENING AS THE NEXT UPPER TROUGH APPROACHES. THAT SYSTEM SHOULD BRING SHOWERS SUNDAY NIGHT AND MONDAY. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1149 AM CDT WED SEP 10 2014 A STRONG SURFACE LOW IS PROJECTED TO TRACK NORTHEAST THIS AFTERNOON INTO NORTHERN LOWER MICHIGAN AND INTO SOUTHEAST ONTARIO/ SOUTHWEST QUEBEC TONIGHT. RAIN AND DRIZZLE WILL CONTINUE INTO MIDDLE AFTERNOON...BUT THEN DIMINISH FROM SOUTHWEST TO NORTHEAST ACROSS THE REGION. CIGS AND VSBYS WILL MAINLY BE IN THE MVFR/IFR RANGE FOR AS LONG AS THE RAIN/DRIZZLE CONTINUES. ONCE THE PRECIP EXITS...VSBYS WILL IMPROVE TO P6SM BUT CIGS WILL REMAIN BETWEEN 1K-2K FEET. VERY SLOW IMPROVEMENT IS EXPECTED ON WEDNESDAY WITH SOME BREAKING UP OF THE CLOUD MASS DURING THE AFTERNOON. WINDS WILL SHIFT AROUND TO THE NORTHWEST THIS AFTERNOON AND REMAIN GUSTY THROUGH THURSDAY MORNING. && .MARINE... ISSUED AT 242 PM CDT WED SEP 10 2014 NORTHWEST WINDS WILL RAPIDLY STRENGTHEN LATE THIS AFTERNOON INTO EARLY THIS EVENING BEHIND A DEPARTING LOW PRESSURE SYSTEM. WITH INCREASING INSTABILITY OVER THE CENTRAL BAY OF GREEN BAY...MIXING WILL SUPPORT 40 TO 45 KT WINDS AT 925 AND 900MB TO REACH THE SURFACE. THIS WIND DIRECTION IS ALSO FAVORABLE FOR HIGHER END GUSTS THROUGH DEATHS DOOR. ISSUE A GALE WARNING FOR THE CENTRAL BAY AND LAKE MICHIGAN SHORELINE THROUGH 18Z...THOUGH GALES WILL LIKELY ONLY BE POSSIBLE THROUGH SUNRISE ON THURSDAY. && .HYDROLOGY... ISSUED AT 242 PM CDT WED SEP 10 2014 NORTH-CENTRAL WISCONSIN PICKED UP THE MOST RAINFALL FOR THIS EVENT...WITH SCATTERED LOCATIONS REACHING ABOVE 2 INCHES. NO REPORTS OF FLOODING SO FAR TODAY. AREA RIVERS ARE RISING BUT ALSO REPORTING NO SIGNIFICANT PROBLEMS. WILL CANCEL THE FLOOD WATCH WITH THIS ISSUANCE. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......RDM AVIATION.......MPC MARINE.........MPC HYDROLOGY......MPC