Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/25/15


...PREVIOUS EXTENDED FORECAST DISCUSSION...

SAT-TUE... MID LVL SHORTWAVE OVER THE ROCKIES WILL COMBINE WITH THE SHORTWAVE OVER THE NE GOMEX TO COLLAPSE WEAK MID LVL RIDGING ALONG AND W OF THE MS RIVER VALLEY AS THE SFC RIDGE SLOWLY CREEPS INTO THE NW ATLC. THE INVERTED TROF OVER THE ERN GOMEX/CAROLINA COAST WILL SLOWLY LIFT UP ERN SEABOARD BUT WILL REMAIN TRAPPED BENEATH THE RIDGE IN A TEXTBOOK REX-BLOCKING PATTERN. DEEP LYR MOISTURE WILL REMAIN ACRS THE FL PENINSULA INTO EARLY NEXT WEEK...MODEL SOUNDING INDICATE PWAT VALUES HOLDING BTWN 1.8"-2.2" THRU THE REMAINDER OF THE FCST. THE GFS CONTINUES TO LOOK PARTICULARLY WET INTO EARLY NEXT WEEK AS AS SEVERAL MID LEVEL VORT IMPULSES EJECT FROM THE WESTERN CARIB/SE GOMEX...ECMWF MAINTAINS A WEAKER AND LESS ORGANIZED VORT FIELD. CURIOUSLY THOUGH...POPS ON THE THE ECMWF NUMERICAL GUIDANCE CAME IN A LITTLE BIT HIGHER THAN THE GFS. BOTH MODELS CONTINUE TO SHOW A SFC LOW DVLPG IN THE VCNTY OF THE YUCATAN PENINSULA ON SUN...LIFTING NORTH INTO THE N CENTRAL GOMEX INTO TUE. GFS IS MUCH MORE BULLISH ON ITS POTENTIAL THAN THE EURO MODEL...BUT NEVERTHELESS WILL BE AN AREA TO WATCH. && .AVIATION...AS SCT SHRA`S/ISOLD TSRA`S SPREAD INLAND THIS AFTN EXPECT TEMPO MVFR CIGS/VSBYS. NERLY WINDS REMAIN GUSTY ALONG THE VOLUSIA COAST AND ARE LIGHTER SOUTHWARD WHERE THE PGRAD IS WEAKER. OVERALL ACTIVITY WILL BE ON A DOWNWARD TREND THIS EVENING...BUT MAY STILL HAVE ISOLD-SCT SHRA ACTIVITY CONTINUING OVER VOLUSIA COUNTY AND ALONG THE TREASURE COAST AND OKEECHOBEE COUNTY. SOME PATCHY FOG/LOW STRATUS AGAIN POSSIBLE LATE OVERNIGHT/EARLY THU MORNING...ESP ACROSS THE I-4 CORRIDOR. && .MARINE...AFTERNOON-TONIGHT...STUBBORN FRONTAL BOUNDARY OVER THE CENTRAL PENINSULA WITH WEAK AREA OF CIRCULATION OFF OF THE VOLUSIA COAST PROVIDING OCNL SHRA/ISOLD TSRA OVER THE NORTHERN COASTAL WATERS...AS WELL AS GUSTY NERLY WINDS WITH SEAS BUILDING UP TO 6 FT WELL OFFSHORE THE VOLUSIA COAST. SEAS MAINLY 2-4 FT NEAR SHORE AND 3- 5 FT ELSEWHERE OFFSHORE SOUTHWARD FROM THE CAPE. WIND SPEEDS EXPECTED TO DECREASE TONIGHT TO 10 KTS OR LESS AREAWIDE. ...PREVIOUS EXTENDED MARINE DISCUSSION... THU-SUN...WEAK INVERTED TROF EXTENDING FROM THE ERN GOMEX UP THE CAROLINA COAST IS TRAPPED BLO A LARGE CONTINENTAL RIDGE AXIS BLANKETING MOST OF THE CONUS E OF THE MS RIVER VALLEY. PRESENCE OF THE TROF WILL KEEP THE LCL PGRAD DISRUPTED...RESULTING IN A LIGHT TO GENTLE ERLY BREEZE THRU THE UPCOMING WEEKEND. WIND DIRECTION WILL VARY BTWN E/NE NORTH OF SEBASTIAN INLET TO E/SE SOUTH OF THE INLET AS THE AMPLITUDE OF THE TROF OSCILLATES BTWN HI AND LOW...BUT LARGELY AOB 10KTS. PERSISTENT ERLY SWELL WILL CONTINUE TO ENHANCE WAVE HEIGHTS...BUT WILL GRADUALLY DAMPEN OUT INTO THE WEEKEND. COMBINED SEAS 3-4FT NEARSHORE AND 4-5FT OFFSHORE THRU FRI...UP TO 6FT IN THE GULF STREAM. SEAS DIMINISHING TO 3-4FT AREAWIDE BY DAYBREAK SAT...CONTG THRU THE WEEKEND. && .HYDROLOGY...THE ST. JOHNS RIVER AT ASTOR /ASTF1/ HAS REACHED ACTION STAGE LATE WED AFTERNOON AND A HYDROLOGIC STATEMENT /RVSMLB/ HAS BEEN SENT. RIVER LEVEL RISE PARTLY DUE TO NORTHERLY WIND COMPONENT IMPEDING DOWNSTREAM FLOW. RIVER LEVELS EXPECTED TO REMAIN NEAR OR NOT TOO FAR AWAY FROM THE 2.5 FT ACTION STAGE FOR THE NEXT FEW DAYS. && .PRELIMINARY POINT TEMPS/POPS... DAB 73 87 71 85 / 30 50 40 60 MCO 73 88 73 88 / 20 60 30 60 MLB 73 87 72 86 / 10 50 30 60 VRB 74 87 71 85 / 20 60 30 60 LEE 72 88 73 87 / 20 60 30 60 SFB 73 89 73 87 / 20 60 30 60 ORL 74 88 74 88 / 20 60 30 60 FPR 72 86 72 85 / 30 60 30 60 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ IMPACT WX....CRISTALDI HYDROLOGY....GLITTO FORECASTS....WIMMER
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
707 PM EDT WED SEP 23 2015 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH TONIGHT AS WEAK LOW PRESSURE MEANDERS OFFSHORE. HIGH PRESSURE WILL THEN PREVAIL INLAND WHILE A COASTAL TROUGH PERSISTS INTO EARLY NEXT WEEK JUST OFFSHORE. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 23/21Z SURFACE...RADAR AND SURFACE ANALYSIS PLACED DUAL LOW PRESSURE CENTERS OFF THE SOUTHEAST U.S. COAST WITH A WELL-DEFINED HIGH PRESSURE WEDGE ANCHORED ACROSS INLAND AREAS. THE FIRST LOW...ESTIMATED AT 1012 HPA...WAS POSITIONED ABOUT 115 MILES SOUTHEAST OF CAPE HATTERAS WITH A SECOND LOW...ESTIMATED AT 1010 HPA...MEANDERING 90 MILES NORTHEAST OF CAPE CANAVERAL. THE HIGH PRESSURE WEDGE WILL MOVE LITTLE OVERNIGHT WHILE THE BROAD SURFACE TROUGH WITH EMBEDDED LOWS RETROGRADE SLIGHTLY WEST AND SOUTHWEST. THE LATEST HIGH RESOLUTION GUIDANCE HAS SLOWED THE ONSET OF ISENTROPIC ASSENT UNTIL AFTER SUNRISE THURSDAY...WHICH SEEMS REASONABLE GIVEN THE LACK OF CONVECTION SO FAR OVER THE COASTAL WATERS. WITH THE RAP AND H3R BOTH SHOWING A SIMILAR SIGNAL WITH SUPPORT FROM THE LATEST SREF MEAN...HAVE LOWERED POPS QUITE A BIT WITH THE EARLY EVENING UPDATE. THE UPDATED POP FORECAST SHOWS POPS MAXING OUT 20-30 PERCENT ACROSS THE COASTAL COUNTIES WITH NON- MENTIONABLE POPS INLAND THROUGH SUNRISE. DO EXPECT A QUICK EXPANSION OF RAIN AFTER SUNRISE THURSDAY...ESPECIALLY ACROSS SOUTHEAST SOUTH CAROLINA. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... THURSDAY AND THURSDAY NIGHT...A WEAK UPPER LEVEL LOW NEAR THE SOUTHERN GEORGIA/ALABAMA LINE THURSDAY AND THURSDAY NIGHT COMBINED WITH A WEAK AREA OF SURFACE LOW PRESSURE MOVING INLAND NEAR THE GEORGIA/FLORIDA COAST WILL RESULT IN COPIOUS AMOUNTS OF MOISTURE WITH PRECIPITABLE WATER VALUES AROUND OR OVER TWO INCHES MOVING INTO THE AREA FROM THE SOUTH AND SOUTHEAST. LOW LEVEL SPEED CONVERGENCE ALONG THE COAST...AN INLAND WEDGE OF HIGH PRESSURE...THE PROXIMITY OF THE COASTAL TROUGH AND WEAK UPPER LEVEL DISTURBANCES MOVING THROUGH WILL LIKELY RESULT IN SEVERAL ROUNDS OF SHOWERS WITH A FEW THUNDERSTORMS...ESPECIALLY CLOSER TO THE COAST. MODELS HAVE TRENDED HIGHER WITH RAIN CHANCES...SO RAISED POPS FOR ALL AREAS...BUT STILL MAINTAINED A DECENT GRADIENT FROM 70 TO 80 PERCENT NORTH TO 30 TO 40 PERCENT SOUTHWEST. DUE TO THE HIGH MOISTURE CONTENT OF THE AIR...THERE COULD BE SOME AREAS OF HEAVY RAINFALL...ESPECIALLY IN THE NORTH. CLOUDS AND PRECIPITATION WILL KEEP HIGHS ONLY IN THE MID TO UPPER 70S. ANY AREAS WHERE RAIN PERSISTS FOR MUCH OF THE DAY...HIGHS COULD BE HELD DOWN INTO THE LOWER 70S. FRIDAY THROUGH SATURDAY...THE COASTAL TROUGH WILL WEAKEN AND FLATTEN OUT AND SOMEWHAT DRIER AIR WILL TRY TO WORK INTO THE AREA...ESPECIALLY BY SATURDAY AS THE WEAK UPPER LEVEL LOW LIFTS NORTHWESTWARD AWAY FROM THE AREA. MODELS ARE IN DISAGREEMENT ABOUT WHEN THE WEDGE OF INLAND HIGH PRESSURE WILL BREAK DOWN. THE 12Z NAM SHOWS IT BEGINNING TO BREAK DOWN ON FRIDAY...THE 12Z GFS ON SATURDAY AND THE 12Z ECMWF AND CANADIAN SHOW IT PERSISTING THROUGH SATURDAY. DUE TO THE FACT THAT THE BIAS OF THE MODELS IS TO BREAK DOWN THE WEDGE TOO SOON...GENERALLY FOLLOWED THE ECMWF AND CANADIAN MODELS WHICH KEEPS HIGHS ON FRIDAY AND SATURDAY ACROSS MUCH OF THE AREA IN THE MID TO UPPER 70S. IF THE WEDGE BREAKS DOWN SOONER...HIGHS COULD BE WELL INTO THE 80S....ESPECIALLY BY SATURDAY. THE THREAT FOR PRECIPITATION WILL RANGE FROM LIKELY NORTH TO CHANCE SOUTHWEST ON FRIDAY AND THEN WILL DECREASE WITH CHANCE POPS BY SATURDAY FOR ALL AREAS...AGAIN HIGHEST NORTH TO LOWEST SOUTHWEST. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... THROUGH THE LONG TERM PERIOD...THE PATTERN ALOFT WILL BECOME QUITE NEBULOUS AS THE PRIMARY BELT OF WESTERLIES REMAINS WELL TO THE NORTH UP ACROSS CANADA. THE LATE WEEK UPPER LOW WILL DISSIPATE AND SHIFT NORTHWARD AND THE MAIN PATTERN WILL FEATURE A MODEST RIDGE BECOMING CENTERED NEAR THE BAHAMAS. WEAKER HIGH PRESSURE WILL BE THE PRIMARY FEATURE AT THE SURFACE AND WILL PERSIST ACROSS INLAND AREAS THROUGH LATTER PART OF THE WEEKEND AND INTO EARLY NEXT WEEK. OVERALL...IT LOOKS LIKE A PERIOD OF LOWERING POPS THANKS TO THE ABSENCE OF ANY FORCING FOR ASCENT. TEMPERATURES SHOULD DISPLAY A MODEST WARMING TREND...BEING SLIGHTLY BELOW NORMAL FOR LATE SEPTEMBER. && .AVIATION /23Z WEDNESDAY THROUGH MONDAY/... KCHS...VFR FOR MUCH OF THE NIGHT WITH DETERIORATING CONDITIONS FROM 09Z ON. EXPECT MVFR CIGS TO DEVELOP A FEW HOURS BEFORE SUNRISE THEN CONTINUE TO SLOWLY LOWER THROUGH THE DAY. THERE ARE INDICATIONS THAT IFR CIGS COULD DEVELOP BY MID-MORNING...BUT SUSPECT THIS WILL BE OFFSET SOMEWHAT BY RAIN MOVING IN FROM OFF THE ATLANTIC AS A TROUGH OF LOW PRESSURE MEANDERS CLOSER TO THE COAST. VSBYS WILL DROP AS WELL AS LIGHT RAIN OVERSPREAD THE AREA...BUT WILL LIMIT VSBYS TO MVFR FOR NOW FROM 18Z ON. THERE WILL LIKELY BE POCKETS OF LOWER VSBYS...BUT CONFIDENCE IS NOT HIGH ENOUGH TO JUSTIFY A MENTION THIS FAR OUT. KSAV...VFR FOR MUCH OF THE NIGHT...ALTHOUGH CIGS WILL BEGIN TO LOWER TO MVFR BY SUNRISE. CIGS ARE EXPECTED TO HOLD IN THE MVFR AREA FOR MUCH OF THE DAY AS A TROUGH OF LOW PRESSURE DRAWS CLOSER TO THE COAST. THERE ARE SIGNS THAT SOME LIGHT RAIN COULD PASS OVER THE TERMINAL BY MID-MORNING BEFORE CLEARNING OUT...BUT CONFIDENCE IS ONLY MODEST AT BEST THIS FAR OUT. WILL NOT INTRODUCE PREVAILING -RA JUST YET. EXTENDED AVIATION...HIGH CHANCES FOR AN EXTENDED PERIOD OF WIDESPREAD FLIGHT RESTRICTIONS THURSDAY NIGHT THROUGH AT LEAST FRIDAY NIGHT. CONDITIONS SHOULD THEN BEGIN TO GRADUALLY IMPROVE OVER THE WEEKEND. && .MARINE... TONIGHT...FAIRLY TIGHT GRADIENT PERSISTS TONIGHT WITH NE WINDS 20-25 KT WITH GUSTS NEAR 30 KT OVER THE ATLANTIC WATERS. HARBOR WINDS WILL REMAIN 15 KT OR SO OVERNIGHT. MAINTAINED SMALL CRAFT ADVISORY ALL WATERS EXCEPT THE HARBOR THROUGH TONIGHT. SEAS WILL AVERAGE 4-6 FT NEARSHORE WATERS AND 7-9 FT OFFSHORE WATERS. THURSDAY THROUGH SUNDAY...STRONG HIGH PRESSURE WILL PERSIST INLAND AS A COASTAL TROUGH GRADUALLY WEAKEN AS IT PUSHES CLOSE TO THE COAST...RESULTING IN THE PRESSURE GRADIENT GRADUALLY WEAKENING ACROSS THE LOCAL WATERS. ELEVATED SEAS FROM A LONG FETCH OF NORTHEASTERLY WINDS AT THE START OF THE PERIOD WILL GRADUALLY DIMINISH AND SMALL CRAFT ADVISORIES WILL GRADUALLY BE DROPPED ON THURSDAY FOLLOWED BY MORE TRANQUIL CONDITIONS THURSDAY NIGHT THROUGH SUNDAY. && .TIDES/COASTAL FLOODING... ELEVATED TIDES WILL LINGER INTO THE WEEKEND WITH POTENTIAL FOR SHALLOW COASTAL FLOODING AROUND THE LATE DAY HIGH TIDE CYCLE. ADDITIONAL COASTAL FLOOD ADVISORIES ARE LIKELY. RIP CURRENTS...AN ENHANCED RISK FOR RIP CURRENTS POSSIBLE FRIDAY THROUGH SUNDAY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THURSDAY FOR AMZ350-352- 354. SMALL CRAFT ADVISORY UNTIL 5 PM EDT THURSDAY FOR AMZ374. && $$ ST
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
554 PM EDT WED SEP 23 2015 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH TONIGHT AS WEAK LOW PRESSURE MEANDERS OFFSHORE. HIGH PRESSURE WILL THEN PREVAIL INLAND WHILE A COASTAL TROUGH PERSISTS INTO EARLY NEXT WEEK JUST OFFSHORE. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 23/21Z SURFACE...RADAR AND SURFACE ANALYSIS PLACED DUAL LOW PRESSURE CENTERS OFF THE SOUTHEAST U.S. COAST WITH A WELL-DEFINED HIGH PRESSURE WEDGE ANCHORED ACROSS INLAND AREAS. THE FIRST LOW...ESTIMATED AT 1012 HPA...WAS POSITIONED ABOUT 115 MILES SOUTHEAST OF CAPE HATTERAS WITH A SECOND LOW...ESTIMATED AT 1010 HPA...MEANDERING 90 MILES NORTHEAST OF CAPE CANAVERAL. THE HIGH PRESSURE WEDGE WILL MOVE LITTLE OVERNIGHT WHILE THE BROAD SURFACE TROUGH WITH EMBEDDED LOWS RETROGRADE SLIGHTLY WEST AND SOUTHWEST. THE LATEST HIGH RESOLUTION GUIDANCE HAS SLOWED THE ONSET OF ISENTROPIC ASSENT UNTIL AFTER SUNRISE THURSDAY...WHICH SEEMS REASONABLE GIVEN THE LACK OF CONVECTION SO FAR OVER THE COASTAL WATERS. WITH THE RAP AND H3R BOTH SHOWING A SIMILAR SIGNAL WITH SUPPORT FROM THE LATEST SREF MEAN...HAVE LOWERED POPS QUITE A BIT WITH THE EARLY EVENING UPDATE. THE UPDATED POP FORECAST SHOWS POPS MAXING OUT 20-30 PERCENT ACROSS THE COASTAL COUNTIES WITH NON- MENTIONABLE POPS INLAND THROUGH SUNRISE. DO EXPECT A QUICK EXPANSION OF RAIN AFTER SUNRISE THURSDAY...ESPECIALLY ACROSS SOUTHEAST SOUTH CAROLINA. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... THURSDAY AND THURSDAY NIGHT...A WEAK UPPER LEVEL LOW NEAR THE SOUTHERN GEORGIA/ALABAMA LINE THURSDAY AND THURSDAY NIGHT COMBINED WITH A WEAK AREA OF SURFACE LOW PRESSURE MOVING INLAND NEAR THE GEORGIA/FLORIDA COAST WILL RESULT IN COPIOUS AMOUNTS OF MOISTURE WITH PRECIPITABLE WATER VALUES AROUND OR OVER TWO INCHES MOVING INTO THE AREA FROM THE SOUTH AND SOUTHEAST. LOW LEVEL SPEED CONVERGENCE ALONG THE COAST...AN INLAND WEDGE OF HIGH PRESSURE...THE PROXIMITY OF THE COASTAL TROUGH AND WEAK UPPER LEVEL DISTURBANCES MOVING THROUGH WILL LIKELY RESULT IN SEVERAL ROUNDS OF SHOWERS WITH A FEW THUNDERSTORMS...ESPECIALLY CLOSER TO THE COAST. MODELS HAVE TRENDED HIGHER WITH RAIN CHANCES...SO RAISED POPS FOR ALL AREAS...BUT STILL MAINTAINED A DECENT GRADIENT FROM 70 TO 80 PERCENT NORTH TO 30 TO 40 PERCENT SOUTHWEST. DUE TO THE HIGH MOISTURE CONTENT OF THE AIR...THERE COULD BE SOME AREAS OF HEAVY RAINFALL...ESPECIALLY IN THE NORTH. CLOUDS AND PRECIPITATION WILL KEEP HIGHS ONLY IN THE MID TO UPPER 70S. ANY AREAS WHERE RAIN PERSISTS FOR MUCH OF THE DAY...HIGHS COULD BE HELD DOWN INTO THE LOWER 70S. FRIDAY THROUGH SATURDAY...THE COASTAL TROUGH WILL WEAKEN AND FLATTEN OUT AND SOMEWHAT DRIER AIR WILL TRY TO WORK INTO THE AREA...ESPECIALLY BY SATURDAY AS THE WEAK UPPER LEVEL LOW LIFTS NORTHWESTWARD AWAY FROM THE AREA. MODELS ARE IN DISAGREEMENT ABOUT WHEN THE WEDGE OF INLAND HIGH PRESSURE WILL BREAK DOWN. THE 12Z NAM SHOWS IT BEGINNING TO BREAK DOWN ON FRIDAY...THE 12Z GFS ON SATURDAY AND THE 12Z ECMWF AND CANADIAN SHOW IT PERSISTING THROUGH SATURDAY. DUE TO THE FACT THAT THE BIAS OF THE MODELS IS TO BREAK DOWN THE WEDGE TOO SOON...GENERALLY FOLLOWED THE ECMWF AND CANADIAN MODELS WHICH KEEPS HIGHS ON FRIDAY AND SATURDAY ACROSS MUCH OF THE AREA IN THE MID TO UPPER 70S. IF THE WEDGE BREAKS DOWN SOONER...HIGHS COULD BE WELL INTO THE 80S....ESPECIALLY BY SATURDAY. THE THREAT FOR PRECIPITATION WILL RANGE FROM LIKELY NORTH TO CHANCE SOUTHWEST ON FRIDAY AND THEN WILL DECREASE WITH CHANCE POPS BY SATURDAY FOR ALL AREAS...AGAIN HIGHEST NORTH TO LOWEST SOUTHWEST. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... THROUGH THE LONG TERM PERIOD...THE PATTERN ALOFT WILL BECOME QUITE NEBULOUS AS THE PRIMARY BELT OF WESTERLIES REMAINS WELL TO THE NORTH UP ACROSS CANADA. THE LATE WEEK UPPER LOW WILL DISSIPATE AND SHIFT NORTHWARD AND THE MAIN PATTERN WILL FEATURE A MODEST RIDGE BECOMING CENTERED NEAR THE BAHAMAS. WEAKER HIGH PRESSURE WILL BE THE PRIMARY FEATURE AT THE SURFACE AND WILL PERSIST ACROSS INLAND AREAS THROUGH LATTER PART OF THE WEEKEND AND INTO EARLY NEXT WEEK. OVERALL...IT LOOKS LIKE A PERIOD OF LOWERING POPS THANKS TO THE ABSENCE OF ANY FORCING FOR ASCENT. TEMPERATURES SHOULD DISPLAY A MODEST WARMING TREND...BEING SLIGHTLY BELOW NORMAL FOR LATE SEPTEMBER. && .AVIATION /22Z WEDNESDAY THROUGH MONDAY/... CEILINGS HAVE BEEN TEETERING ON MVFR TODAY. MVFR CEILINGS EXPECTED TO RETURN TO KCHS THIS EVENING AND PERSIST INTO THU MORNING. RAIN WILL OVERSPREAD THE TERMINAL LATE TONIGHT AND REMAIN INTO THURSDAY. FLIGHT RESTRICTIONS ARE TRICKIER AT KSAV THIS EVENING WHERE WE THINK VFR WILL PREVAIL INTO THE OVERNIGHT HOURS BEFORE DROPPING TO MVFR. SOME RAIN IS POSSIBLE LATE TONIGHT INTO THURSDAY. CANNOT RULE OUT SOME IFR CEILINGS AT EITHER SITE LATE TONIGHT AND THU MORNING THOUGH THE FAIRLY STRONG LOW-LEVEL WINDS SHOULD PRECLUDE A GREATER IFR RISK. EXTENDED AVIATION...HIGH CHANCES FOR AN EXTENDED PERIOD OF WIDESPREAD FLIGHT RESTRICTIONS THURSDAY NIGHT THROUGH AT LEAST FRIDAY NIGHT. CONDITIONS SHOULD THEN BEGIN TO GRADUALLY IMPROVE OVER THE WEEKEND. && .MARINE... TONIGHT...FAIRLY TIGHT GRADIENT PERSISTS TONIGHT WITH NE WINDS 20-25 KT WITH GUSTS NEAR 30 KT OVER THE ATLANTIC WATERS. HARBOR WINDS WILL REMAIN 15 KT OR SO OVERNIGHT. MAINTAINED SMALL CRAFT ADVISORY ALL WATERS EXCEPT THE HARBOR THROUGH TONIGHT. SEAS WILL AVERAGE 4-6 FT NEARSHORE WATERS AND 7-9 FT OFFSHORE WATERS. THURSDAY THROUGH SUNDAY...STRONG HIGH PRESSURE WILL PERSIST INLAND AS A COASTAL TROUGH GRADUALLY WEAKEN AS IT PUSHES CLOSE TO THE COAST...RESULTING IN THE PRESSURE GRADIENT GRADUALLY WEAKENING ACROSS THE LOCAL WATERS. ELEVATED SEAS FROM A LONG FETCH OF NORTHEASTERLY WINDS AT THE START OF THE PERIOD WILL GRADUALLY DIMINISH AND SMALL CRAFT ADVISORIES WILL GRADUALLY BE DROPPED ON THURSDAY FOLLOWED BY MORE TRANQUIL CONDITIONS THURSDAY NIGHT THROUGH SUNDAY. && .TIDES/COASTAL FLOODING... ELEVATED TIDES WILL LINGER INTO THE WEEKEND WITH POTENTIAL FOR SHALLOW COASTAL FLOODING AROUND THE LATE DAY HIGH TIDE CYCLE. ADDITIONAL COASTAL FLOOD ADVISORIES ARE LIKELY. RIP CURRENTS...AN ENHANCED RISK FOR RIP CURRENTS POSSIBLE FRIDAY THROUGH SUNDAY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THURSDAY FOR AMZ350-352- 354. SMALL CRAFT ADVISORY UNTIL 5 PM EDT THURSDAY FOR AMZ374. && $$ ST
AREA FORECAST DISCUSSION
NWS DES MOINES IA
435 AM CDT WED SEP 23 2015 .SHORT TERM /TODAY/... ISSUED AT 401 AM CDT WED SEP 23 2015 OBVIOUS CONCERN TODAY WILL BE PRECIP TRENDS. CURRENT SITUATION HAS SRN END OF SIOUXLAND MCS SEEMINGLY ANCHORED IN PLACE WITH LOW LEVEL MOISTURE TRANSPORT BALANCING MEAN WIND. THIS RESULTS IN NEGLIGIBLE CORFIDI VECTORS AND SLOW CELL MOVEMENT. HOWEVER MORE WIDESPREAD AND ELEVATED WARM/THETA-E ADVECTION IS ALSO PUSHING NORTHWARD AND RESULTING IN EXPANSION ACROSS SD...BUT NOT FARTHER INTO NW IA AS OF YET. FEEL THIS WILL HAPPEN SOON HOWEVER SO HAVE POPS TO LIKELY DURING THE MORNING. LOOKING FARTHER UPSTREAM MOISTURE AND FAIRLY DEEP FORCING ASSOCIATED WITH TD REMNANTS BUILDS INTO WRN IA BY AFTERNOON. ALTHOUGH CLIMATOLOGICAL PERCENTILE EXTREMES ARE FARTHER WEST OF FORECAST AREA...STILL FEEL WARM CLOUD DEPTHS OVER 3.5KM AND PWATS PUSHING 1.75 WITHIN A ZONE OF STEADY MOISTURE TRANSPORT ARE MORE THAN SUFFICIENT FOR EFFICIENT RAINS. CONCERN IS THAT LEFT OVER CONVERGENCE FROM SIOUXLAND MCS WILL INTERACT WITH THIS APPROACHING FORCING AND MOISTURE TO PRODUCE HEAVY RAINS. HI RES HOPWRF AND NCAR ENSEMBLE NEIGHBORHOOD PROBABILITIES OF A FEW INCHES OF RAIN ARE QUITE HIGH INTO IA LATER TODAY SO HAVE ADDED HEAVY RAIN WORDING. THIS MAKES SENSE CONSIDERING THE ENVIRONMENT WITH MOISTURE TRANSPORT AND FAIRLY WEAK MEAN WIND PARALLEL THROUGH THE DAY. OUR NW COUNTIES ARE NOT TOPOGRAPHICALLY FAVORABLE FOR FLASH FLOODING AND HAVE DECENT TILING...BUT THREE HOUR FLASH FLOOD GUIDANCE VALUES ARE GENERALLY IN THE 2.5 TO 2.75 INCH RANGE. A FLASH FLOOD WATCH MAY NEED TO BE CONSIDERED IF CONFIDENCE IN THE EASTERN EXTENT OF HEAVY RAIN INCREASES. TEMP CONFIDENCE IS NOT THE GREATEST DUE TO PRECIP POTENTIAL. THERE MAY BE QUITE A GRADIENT NW-SE. KEPT NW IA IN THE MID 70S WITH SERN SECTIONS JUST A TAD BELOW PERSISTENCE. .LONG TERM /TONIGHT THROUGH TUESDAY/... ISSUED AT 401 AM CDT WED SEP 23 2015 THURSDAY INTO EARLY FRIDAY WILL BE THE HIGHLIGHT OF WHAT SHOULD BE A QUIET LONG TERM FCST PERIOD. PRECIP...AS HIGHLIGHTED IN THE SHORT TERM DISCUSSION...WILL LIKELY BE ONGOING IN OUR W/NW TO START THIS LONG TERM PERIOD. MODELS BEGINNING TO SHOW CONSISTENCY WITH HANDLING EVOLUTION OF THIS SYSTEM. GFS ON AN ISLAND OF ITS OWN WITH TRANSPORTING MOISTURE EAST AND NORTH INTO EASTERN IOWA SO HAVE LEANED AWAY FROM IT. EURO...UKMET...AND THE NAM HAVE BEEN STRONGLY ADVOCATING A MORE SOUTHERLY TRACK FOR THE SFC LOW. WITH THE GULF CLOSED...THIS SYSTEM IS LOSES ITS MOISTURE REINFORCEMENT AND GRADUALLY WEAKENS AFTER 12Z THU. PWAT VALUES WILL BE GRADUALLY DECREASING THROUGHOUT THURSDAY...BUT AFTER STARTING OFF ALMOST IN THE +2 TO +3 STD DEV RANGE EARLY ON...THERE WILL STILL BE ENOUGH MOISTURE PRESENT TO KICK OUT AT LEAST A QUARTER TO HALF AN INCH OF RAIN IN OUR WEST AS PRECIP EFFICIENCY SHOULD REMAIN DECENT. CAPE VALUES ALSO EFFECTIVELY DECREASE THROUGHOUT THURSDAY...SUGGESTING WEAKENING OF THIS SYSTEM. BULK SHEAR VALUES REMAIN UNDER 30 KTS...WHICH...WHEN COUPLED WITH DWINDLING INSTABILITY...NULLIFY SVR WX CHANCES FOR THURSDAY. FOR FRIDAY INTO THE WEEKEND...AN UPPER LEVEL RIDGE WILL MOVE ACROSS THE SOUTHWESTERN CONUS TOWARDS THE MIDWEST. SFC HIGH PRESSURE WILL BE LOCATED OVER THE GREAT LAKES AND WILL SERVE AS A PRECIP SHIELD FOR OUR CWA AS SUBSIDENCE SHOULD BE IN PLACE FOR A FEW DAYS. 850MB TEMPERATURES NEAR 15C LOOK TO BE AROUND 1 STD DEV ABOVE NORMAL AND SHOULD TRANSLATE TO DAYTIME HIGHS IN THE MID 70S TO LOW 80S. PERSISTENCE WILL PROVIDE A GOOD FCST STARTING POINT. BEYOND THIS WEEKEND...EURO AND GFS ACTUALLY COME INTO AGREEMENT WITH BRINGING A COLD FRONT THROUGH THE REGION SOMETIME LATE MONDAY INTO TUESDAY. THE GFS IS SIGNALING PWATS IN THE 1.5 INCH RANGE SO THIS APPEARS TO BE OUR NEXT BEST PRECIP CHANCE AFTER EARLY FRIDAY. BEHIND THE BOUNDARY...MUCH COOLER AIR BE ADVECTED INTO IOWA AS A SIZABLE AREA OF HIGH PRESSURE IS PROGGD TO SLIDE ACROSS THE NORTHERN GREAT PLAINS. 850MB TEMPS MAY REACH DOWN INTO THE SINGLE DIGITS...WHICH WOULD PUT LOWS IN THE UPPER 30S TO MID 40S AND HIGHS IN THE 60S. && .AVIATION...23/06Z ISSUED AT 1142 PM CDT TUE SEP 22 2015 MAIN CONCERN WILL BE PROGRESSION OF CONVECTION OVER NEBRASKA OVERNIGHT. WARM FRONT OVER NEBRASKA IS INITIATION AREA AND MOST OF THE CONVECTION WILL DROP SOUTHEAST OVERNIGHT. HIGH RES HRRR AND 00Z NAM BOTH SUGGEST THAT CONVECTION WILL GENERALLY HOLD OFF UNTIL 13-15Z OVER THE WEST AND SLOWLY BUILD NORTH WITH TIME. CIGS TO MAINLY REMAIN VFR. PATCHY BR WILL BE POSSIBLE BETWEEN 11-14Z. FOR MOST OF THE PERIOD CONVECTION WILL REMAIN WEST OF I35. SOUTHEAST WINDS INCREASE TO NEAR 12KTS WITH POTENTIAL FOR GUSTS 15-17KTS AFT 18Z. /REV && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...SMALL LONG TERM...KOTENBERG AVIATION...REV
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1142 PM CDT TUE SEP 22 2015 .SHORT TERM /TONIGHT/... ISSUED AT 349 PM CDT TUE SEP 22 2015 THIS AFTERNOON AND EVENING`S FORECAST PROVED RATHER CHALLENGING GIVEN THE ONGOING ELEVATED LINE OF CONVECTION THAT...AGAINST THE ODDS...MAINTAINED ITSELF ALONG A NARROW RIBBON OF WEAK 850 MB WAA FROM EASTERN NEBRASKA AND INTO WESTERN IOWA. NO OPERATIONAL CAMS HAVE RESOLVED THIS CONVECTION THROUGHOUT THE DAY (UP UNTIL THE 19Z RUN OF THE HRRR)...SO THIS EVENING`S FORECAST IS BASED HEAVILY ON PERSISTENCE AND THE MEAN CORFIDI VECTORS. GIVEN THE 1500 J/KG OF MUCAPE AND EFFECTIVE SHEAR OF 30 KTS OR MORE...SEE NO REASON FOR WHY THESE STORMS WILL DISSIPATE BEFORE THIS EVENING. THE TRAJECTORY FORECAST TAKES THE STORMS ON A MORE SOUTHERLY COURSE AS THE AFTERNOON PROGRESSES ONWARD...CLIPPING THE WESTERN SIDE OF THE DES MOINES METRO BY 22 TO 23Z. HAVE TAPERED OFF STORMS AFTER 00Z SOUTH AND WEST OF DES MOINES...BUT GIVEN THE LONGEVITY OF THIS EVENT...POP TRENDS WILL NEED TO BE MONITORED CLOSELY AND ADJUSTED AS NEEDED THIS EVENING. ADDITIONAL CELLS ARE IGNITING ALONG AND AHEAD OF A STRONGER PUSH OF 700-500 MB TROPICAL MOISTURE ACROSS EASTERN NEBRASKA...AGAIN POORLY RESOLVED BY THE CAMS. HAVE LEFT SLIGHT CHANCE POPS IN THE WEST THIS EVENING TO ACCOUNT FOR THESE STORMS POSSIBLY BLEEDING INTO THE SOUTHWEST CWA. BACK TO THE SYNOPTIC FORECAST...A STATIONARY BOUNDARY OVER NORTHWEST IOWA SHOULD BEGIN TO LIFT NORTHWARD AS A SURFACE LOW DEVELOPS OVER THE FRONT RANGE IN RESPONSE TO A BROAD 500MB CLOSED LOW WORKING NORTHEASTWARD ACROSS THE FOUR CORNERS REGION. MORE WIDESPREAD THUNDERSTORMS ARE ANTICIPATED TO DEVELOP OVER CENTRAL NEBRASKA AND SOUTH DAKOTA THIS EVENING IN RESPONSE TO FALLING HEIGHTS AND BETTER KINEMATIC FORCING CLOSER TO THE UPPER LOW. THESE STORMS SHOULD BE ENTERING WESTERN IOWA TOWARDS THE END OF THE PERIOD WEDNESDAY MORNING. .LONG TERM /WEDNESDAY THROUGH TUESDAY/... ISSUED AT 349 PM CDT TUE SEP 22 2015 MAIN CONCERN IN THE LONG TERM WILL CENTER AROUND THE WEDNESDAY THROUGH THURSDAY TIMEFRAME. MOISTURE FROM A DECAYING TROPICAL DEPRESSION CONTINUES TO STREAM ACROSS THE PLAINS INTO THE UPPER MIDWEST ALONG WITH WHAT APPEARS TO BE A SHEARED OUT SHORTWAVE PUSHING INTO THE PLAINS. AT THE SURFACE THERE IS GENERAL AGREEMENT AT A SURFACE LOW DEVELOPING OVER THE PLAINS WITH A FRONTAL EXTENDING ACROSS WESTERN/NORTHWESTERN IOWA. AFTER SEEING HOW TODAY EVOLVED I BELIEVE THESE AREAS WILL BE MOST PRONE TO SEE MODERATE TO HEAVY RAINFALL AND SOME STRONGER STORMS...ESPECIALLY WEDNESDAY INTO WEDNESDAY EVENING. THE BEST INSTABILITY WILL OCCUR OVERNIGHT TONIGHT INTO WEDNESDAY MORNING BUT WEDNESDAY EVENING THROUGH THURSDAY THERE IS STRONG QG FORCING ACROSS THE WESTERN HALF OF OUR FORECAST AREA AND THIS IS TIED TO SOME THETA-E ADVECTION AS WELL. PREVIOUS FORECASTS HAD THE AREA OF CONCERN DEPICTED WELL BUT I HAD TO INCREASE THE THUNDERSTORM POTENTIAL FROM THE ISOLATED WORDING WE HAD...ESPECIALLY FOR WEDNESDAY AND THE POTENTIAL FOR SOME MODERATE TO HEAVY RAINFALL WILL ALSO EXIST. I DO NOT THINK THE SEVERE POTENTIAL IS MUCH TO WORRY ABOUT GIVEN THE LACK OF SHEAR AND THE WANING INSTABILITY WITH TIME. BY FRIDAY MODELS BUILD RIDGING ACROSS THE PLAINS AND INTO IOWA AND THEY SUGGEST A WEAK WAVE COMING ACROSS THE PLAINS BUT DIVING TO THE SOUTH/SOUTHEAST BEFORE AFFECTING IOWA. WE HAD DRY GRIDS GOING AND I KEPT THAT GOING. THE WEEKEND CONTINUES TO BE DRY AND MILD. BEYOND SUNDAY THE MODELS ARE ALL OVER THE PLACE. NOW THE GFS DEVELOPS A DEEP TROUGH INTO THE REGION BY TUESDAY NIGHT WHILE THE EURO BUILDS A BIG RIDGE INTO THE PLAINS AND UPPER MIDWEST. PREVIOUS RUNS HAD THE MODELS WITH REVERSED SOLUTIONS. I KEPT WITH PERSISTENCE FOR NOW UNTIL THE MODELS RESOLVE THEIR ISSUES. && .AVIATION...23/06Z ISSUED AT 1142 PM CDT TUE SEP 22 2015 MAIN CONCERN WILL BE PROGRESSION OF CONVECTION OVER NEBRASKA OVERNIGHT. WARM FRONT OVER NEBRASKA IS INITIATION AREA AND MOST OF THE CONVECTION WILL DROP SOUTHEAST OVERNIGHT. HIGH RES HRRR AND 00Z NAM BOTH SUGGEST THAT CONVECTION WILL GENERALLY HOLD OFF UNTIL 13-15Z OVER THE WEST AND SLOWLY BUILD NORTH WITH TIME. CIGS TO MAINLY REMAIN VFR. PATCHY BR WILL BE POSSIBLE BETWEEN 11-14Z. FOR MOST OF THE PERIOD CONVECTION WILL REMAIN WEST OF I35. SOUTHEAST WINDS INCREASE TO NEAR 12KTS WITH POTENTIAL FOR GUSTS 15-17KTS AFT 18Z. /REV && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...SKOW LONG TERM...FAB AVIATION...REV
AREA FORECAST DISCUSSION
NWS GOODLAND KS
226 PM MDT WED SEP 23 2015 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 226 PM MDT WED SEP 23 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS CLOSED UPPER LOW MOVING INTO NORTHCENTRAL NEBRASKA...WITH TROUGH AXIS EXTENDING SOUTH ACROSS OUR CWA INTO SOUTHEAST COLORADO. STRONG PV HEIGHT ANOMALY IS OVER OUR CWA ASSOCIATED WITH SW QUADRANT OF CLOSED LOW. CONVERGENCE ALONG SURFACE TROUGH AXIS CURRENTLY SOUTH OF I-70 AND MID LEVEL ROTATION ALONG SOUTHERN EDGE OF TROUGH HAS AIDED IN THUNDERSTORM INITIATION ALONG AXIS OF STEEP LAPSE RATES/MODERATE CAPE. THIS AFTERNOON-TONIGHT...THUNDERSTORM ACTIVITY WILL CONTINUE TO BE POSSIBLE ALONG SURFACE TROUGH THIS ACTIVITY...POSSIBLY DEVELOPING INTO NW KANSAS. HI RES GUIDANCE SHOWS THIS ACTIVITY REMAINING ROUGHLY ALONG AND SOUTH OF I-70 ALONG TROUGH AXIS. TREND SHOULD BE FOR THIS ACTIVITY TO TRANSITION TO THE SOUTH AS TROUGH AXIS SLIDES SOUTH AND LOW LEVEL STABILIZE OVER OUR CWA. SHOWERS/ISOLATED THUNDERSTORMS IN THE EASTERN CWA MAY CONTINUE TO LINGER THOUGH THE NIGHT AS MOISTURE/MID LEVEL ENERGY CONTINUES TO ROTATE AROUND THE MID LEVEL CLOSED LOW IN NEBRASKA. CAPE AXIS OF ROUGHLY 2000 J/KG WILL SUPPORT SOME STRONGER UPDRAFTS WITH MARGINAL HAIL/WIND THREAT. SHEAR IS UNIMPRESSIVE WITH EFFECTIVE SHEER BELOW 20KT...SO SEVERE THREAT IS LIMITED THIS AFTERNOON AND EVENING. OTHER CONCERN FOR TONIGHT WILL BE POTENTIAL FOR FOG DEVELOPMENT AS SURFACE HIGH PRESSURE BUILDS IN TO THE WESTERN PART OF OUR CWA AND SURFACE LOW SHIFTS EAST. WINDS WILL DECREASE BETWEEN THESE FEATURES AND WITH CLEARING SKIES COMBINE WITH ABUNDANT LOW LEVEL MOISTURE TO FOR FOG DEVELOPMENT ACROSS AT LEAST THE WESTERN PARTS OF OUR CWA. CONFIDENCE IN A DENSE FOG EVENT IS LOWERED BY SHIFT IN WINDS TO THE NW AROUND 12Z...WHICH COULD BRING DRIER AIR AND BETTER BL MIXING. IN ANY CASE WITH SIGNAL DEPICTED BY SREF PROBABILITIES AND NAM/RAP CONFIDENCE WAS HIGH ENOUGH TO ADD PATCHY/AREAS MENTION TO MOST OF CWA. THURSDAY...AS CLOSED LOW MEANDERS EASTWARD AND MEAN TROUGH AXIS SHIFTS SOUTHEAST SUBSIDENCE AND A DEEP DRY MID LEVEL AIR MASS WILL OVERSPREAD OUR CWA. BY LATE THURSDAY AFTERNOON A LOBE OF VORTICITY MAY ROTATE AROUND BACK EDGE OF CLOSED LOW INTO OUR CWA. CONSIDERING THE DRY NATURE OF THE AIR MASS...CONFIDENCE IN MEASURABLE PRECIP WAS TOO LOW TO INCLUDE MENTION THURSDAY AFTERNOON DESPITE SOME FORCING ALOFT AND STEEP LAPSE RATES. THERE IS A SPLIT BETWEEN GUIDANCE REGARDING TEMPS AS SOME GUIDANCE SHOWS REINFORCING CAA BEHIND UPPER LOW OVERSPREADING OUR CWA...WHILE OTHER GUIDANCE SUPPORTS WAA AND HIGH PRESSURE BEGINNING TO BREAK DOWN FROM THE WEST. I BUMPED UP TEMPS IN THE WEST (EASTERN COLORADO) TO THE MID 80S...WITH HIGHS ELSEWHERE GENERALLY IN THE UPPER 70S/NEAR 80F. THIS ISN`T FAR FROM MOST CONSENSUS SOLUTIONS. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 205 PM MDT WED SEP 23 2015 FORECAST PROBLEMS WILL BE LINGERING CHANCES OF PRECIPITATION INTO FRIDAY...STRATUS/FOG THURSDAY NIGHT/FRIDAY...AND HOW MUCH DO TEMPERATURES RECOVER. SATELLITE IS SHOWING AN AMPLIFIED PATTERN OVER THE PACIFIC WHICH THEN TRANSLATES TO A DEVELOPING TROUGH OVER THE WESTERN PORTION OF THE COUNTRY THEN A RIDGE BEING PUSHED INTO THE EASTERN PORTION OF THE COUNTRY. AT JET LEVEL...THE GFS/CANADIAN/NAM STARTED OUT BEST. AT MID LEVELS...THE GFS/UKMET/ECMWF WERE DOING A LITTLE BETTER THAN THE CANADIAN/NAM. THE SREF WAS DOING A LITTLE BETTER THAN THE ECMWF ON THE SURFACE WIND AND PRESSURE FIELD. THE GFS/SREF/CANADIAN WERE DOING THE BEST ON THE LOW LEVEL THERMAL FIELD. THURSDAY NIGHT...MODELS VERY SIMILAR TO 24 HOURS AGO. 70H LOW MOVES TOWARD THE WEST THROUGH THE NIGHT AND IS JUST TO THE EAST/NORTHEAST OF THE AREA. THE ECMWF IS FURTHER NORTH THAN IT WAS PREVIOUSLY. NEGATIVE THETA-E LAPSE RATES ARE IN PLACE WITH NOT A LOT BUT ADEQUATE MID LEVEL MOISTURE. AT THE SAME TIME AS THE LOW MOVES CLOSER...A SHORTWAVE AND MID LEVEL FRONTOGENESIS ROTATES THROUGH THE EASTERN THIRD OF THE AREA. MODELS ARE STILL PRODUCING SOME VERY LIGHT QPF. THINK THERE WILL BE SOME RAINFALL BUT WITH VERY LIGHT AMOUNTS. MODELS HAVE ALSO BEEN CONSISTENT FROM YESTERDAY IN BRINGING/INCREASING LOWER LEVEL MOISTURE ACROSS THE ENTIRE AREA IN THE LAST HALF OF THE NIGHT. SO HAVE INCREASED CLOUD COVER AND INTRODUCED FOG. IT IS POSSIBLE THAT COVERAGE COULD BE GREATER WITH DENSE FOG INDICATED. FRIDAY/FRIDAY NIGHT...EVEN THOUGH 70H LOW WEAKENS...IT CONTINUES TO DROP SOUTH AND WEST INTO THE FORECAST AREA THROUGH THE DAY. AGAIN MODELS NOT SHOWING A LOT OF MOISTURE. HOWEVER MODELS...ESPECIALLY THE ECMWF...IS INDICATING A RATHER STRONG SHORTWAVE TROUGH ROTATING THROUGH THE AREA. ONCE AGAIN THERE WILL BE NEGATIVE THETA-E LAPSE RATES IN PLACE ALONG WITH SOME CAPE AROUND. TQ INDEX ALSO INDICATES INSTABILITY SHOWERS/THUNDERSTORMS POSSIBLE. LIGHT QPF SHOWN BY OUTPUT AS WELL AS WPC WHICH MATCHES THE ABOVE REASONING. IT IS POSSIBLE THAT IT COULD END UP BEING SPRINKLES BUT BELIEVE THERE WILL BE SOME KIND OF SHOWER ACTIVITY AROUND THROUGH THE AFTERNOON. SO PUT IN A SLIGHT CHANCE OF PRECIPITATION FOR THE AFTERNOON. MODELS SHOW THE STRATUS AND FOG BURNING OFF BY LATE MORNING. AM A LITTLE BIT CONCERNED WITH THAT SINCE THE WIND FIELD WILL REMAIN LIGHT AND SHIFT TO A MORE EASTERLY DIRECTION AS THE DAY PROGRESSES. WILL END FOG BY MID MORNING BUT STRATUS MAY HOLD ON LONGER. BECAUSE OF THE CLOUD COVER AND UNFAVORABLE WINDS LOWERED THE HIGH TEMPERATURES A LITTLE. AIR MASS LOOKS LIKE IT STABILIZES RAPIDLY LATE IN THE AFTERNOON WITH THE MAIN LIFT HAVING ALREADY MOVED THROUGH THE AREA. SO FOR NOW WILL LEAVE THE NIGHTTIME PERIOD DRY WITH HIGH SILENT POPS. IT IS POSSIBLE THAT SOMETHING COULD BE ONGOING AT THE BEGINNING BUT IT SHOULD END QUICKLY. RETURN FLOW BEGINS DURING THE NIGHT WITH A LITTLE MORE WIND EXPECTED WITH THE EAST SEEING THE LEAST AMOUNT. MODELS NOT AS HIGH WITH THE LOW LEVEL MOISTURE SO WILL LEAVE OUT ANY MENTION OF FOG FOR NOW. SATURDAY...RIDGE BUILDS INTO THE AREA WITH INCREASING SOUTHERLY WINDS AND WARM AIR ADVECTION. THINK SOME OF THE GUIDANCE IS TOO WARM DUE TO A LACK OF DOWNSLOPE COMPONENT TO THE WIND AND THAT THE FLOW ALOFT WILL STILL BE OUT OF THE NORTH. ADJUSTED THE MAX TEMPERATURES DOWN SLIGHTLY...ESPECIALLY FOR THE CENTRAL AND EASTERN PORTIONS. SATURDAY NIGHT THROUGH WEDNESDAY...MODELS STILL SHOWING A LOT OF DISAGREEMENT IN HOW TO HANDLE THE EASTERN PACIFIC TROUGH AND WESTERN/CENTRAL RIDGE. THE ECMWF AND CANADIAN ARE STILL THE FURTHEST WEST AND MORE CUTOFF WITH THE GFS STILL PUSHING THE TROUGH FURTHER TO THE EAST WHILE RETAINING THE CUTOFF. ALTHOUGH THE GFS IS SLOWER TODAY THAN YESTERDAY. CONSIDERING THE FLOW PATTERN...CONSISTENT ECMWF/CANADIAN AND THE SLOWER GFS...THE MORE AMPLIFIED AND SLOWER SOLUTION LOOKS THE BEST. THE WPC MANUAL PROGS ECHO THIS AS WELL. SAYING THAT IT LOOKS LIKE DRY AND WARMER WEATHER WILL BE THE PREVAILING CONDITIONS FOR THIS PERIOD AND LEFT WHAT THE CRH_INIT GAVE ME. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1131 AM MDT WED SEP 23 2015 MVFR CIGS SHOULD LIFT EARLY IN THE TAF PERIOD...WITH SATELLITE ALREADY SHOWING CLEARING SW OF KGLD AS DRIER AIR ADVECTS INTO THE REGION. OBS INDICATE SIMILAR TRENDS AT KMCK...THOUGH 2500 KFT CIGS MAY LINGER A LITTLE LONGER INTO THE AFTERNOON DUE TO PROXIMITY OF BETTER MOISTURE AXIS. MAIN UPPER LEVEL SYSTEM HAS SHIFTED NORTH...AND BETTER SHOWER COVERAGE HAS MOVED EAST. I STILL EXPECT SHOWERS TO BE POSSIBLE AT BOTH KGLD AND KMCK...HOWEVER BEST CHANCES ARE STILL AT KMCK THROUGH THIS EVENING WITH MAIN UPPER LOW JUST TO THE NORTH-NORTHEAST. STRATUS/FOG SHOULD REDEVELOP AFTER 09-10Z AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION FROM THE WEST...WITH CONDITIONS IMPROVING AFTER 15Z. BEST BL MOISTURE APPEARS TO BE ALONG KS/CO BORDER AND CONFIDENCE IS HIGHER IN IFR CIGS/VIS AT KGLD. I COULD SEE LIFR CONDITIONS DEVELOP AT BOTH TERMINALS...HOWEVER THERE COULD BE JUST ENOUGH MIXING AROUND 12Z WITH SHIFT IN BL FLOW TO THE NW TO LOWER CONFIDENCE IN DENSE FOG/LOWER CIGS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...BULLER AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
221 AM MDT WED SEP 23 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 211 PM MDT TUE SEP 22 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS A SERIES OF H7/H5 UPPER TROUGHS PROPAGATING THROUGH A MEAN SW FLOW ACROSS THE CENTRAL ROCKIES. THE NEAREST UPPER LOW IS NOW MOVING INTO THE SOUTHERN PART OF OUR CWA WITH PLUME OF RICH MID LEVEL MOISTURE SPREADING NORTH OUT OF SW KANSAS. PWATS AS INDICATED BY RAP ANALYSIS ARE NEARING 1.4-1.5 SOUTH OF OUR CWA. STEEP LOW AND MID LEVEL LAPSE RATES HAVE LED TO ISOLATED SHOWER/THUNDERSTORM DEVELOPMENT IN PROXIMITY TO STALLED FRONTAL ZONE ALONG I-70 IN COLORADO. THIS STALLED COLD FRONT EXTENDS NORTH INTO SW AND CENTRAL NEBRASKA WHERE HIGHER CINH HAS LIMITED CONVECTIVE INITIATION. THIS AFTERNOON-TONIGHT...ISOLATED TO SCATTERED THUNDERSTORM ACTIVITY WILL CONTINUE TO BE POSSIBLE AHEAD OF MAIN AREA OF LARGE SCALE FORCING (SOUTH OF TROUGH AXIS. AS THIS UPPER TROUGH SHIFTS NORTH SHOWERS AND THUNDERSTORM SHOULD SPREAD NORTH ALONG/EAST OF CO/KS STATE LINE. A SECOND UPPER LOW/STRONG LOBE OF VORTICITY WILL ROTATE THROUGH THE REGION TONIGHT AND GUIDANCE IS SHOWING A PARTICULARLY STRONG PRECIP SIGNAL WITH THIS SECONDARY UPPER LOW AROUND 06-09Z. BEST INSTABILITY QUICKLY DROPS OFF AFTER 00Z...HOWEVER STEEP MID LEVEL LAPSE RATES AND WEAK CAPE WILL AT LEAST SUPPORT A THREAT FOR EMBEDDED CONVECTION OVERNIGHT. ANOMALOUSLY HIGH PWATS...DEEP MOISTURE ADVECTION...AND CONTINUOUS SOUTH TO NORTH BUILDING/TRAINING OF SHOWERS/THUNDERSTORMS WILL SUPPORT POSSIBLE HEAVY RAIN WITH MANY LOCATIONS RECEIVING ONE HALF TO ONE INCH...POSSIBLY HIGHER. WEDNESDAY...UPPER LOW SHIFTS NORTHEAST AND SLOWS DOWN OVER CENTRAL NEBRASKA...ALLOWING FOR MOIST/WEAKLY UNSTABLE AIR MASS TO LINGER EAST OF STALLED FRONTAL ZONE. COLD POOL ALOFT WILL SUPPORT POSSIBLE SHOWER/THUNDERSTORM REDEVELOPMENT IN THE AFTERNOON...SO WHILE BEST LARGE SCALE FORCING IS NORTHEAST BY MIDDAY WE WILL CONTINUE TO SEE CHANCES THROUGH THE DAY...PARTICULARLY IN THE EAST. GUIDANCE IS SHOWING THE POTENTIAL FOR DRIER AIR TO ADVECT IN FROM THE WEST...SO LOCATIONS IN EASTERN COLORADO AND FAR WESTERN KANSAS MAY REMAIN DRY WEDNESDAY AFTERNOON. I SHOWED A DECREASING TREND IN COVERAGE FROM THE WEST TO THE EAST. HIGH TEMPS ARE TRICKY AS CLEARING/WAA IN THE WEST COULD SUPPORT MID TO UPPER 80S FOR HIGHS...WHILE PERSISTENT CLOUD COVER/SHOWERS EAST OF FRONTAL ZONE/SURFACE TROUGH WOULD HOLD HIGHS DOWN IN THE 70S. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 220 AM MDT WED SEP 23 2015 AN UPPER LEVEL RIDGE WILL BE THE DOMINATE WEATHER FEATURE FOR THE COMING WEEKEND AND FOR THE START OF NEXT WEEK. THE MAIN JET ENERGY AND LIFT WILL REMAIN WELL TO THE NORTH OF THE CENTRAL PLAINS...SO DRY WEATHER AND WARM CONDITIONS IN THE MID TO UPPER 80S ARE EXPECTED. THE NEXT CHANCE FOR SOME PRECIPITATION WOULD BE TUESDAY AS THE GFS DEPICTS A TROUGH EXTENDING INTO THE MIDWESTERN STATES THAT COULD PROVIDE THE NECESSARY LIFT...HOWEVER THE ECMWF INDICATES AN INCREASING AMPLITUDE RIDGE OVER THE HIGH PLAINS REGION. THE LATEST ECMWF RUN IS CONSISTENT FROM PREVIOUS RUNS WHEREAS THE GFS IS COMING MORE IN ALIGNMENT WITH THE ECMWF THAN FROM PREVIOUS RUNS. THAT BEING SAID...THE ECMWF AT THIS CURRENT TIME APPEARS TO BE THE MORE TRUSTWORTHY FORECAST TO USE. THEREFORE...TENDED TO GO MORE WITH THE ECMWF SOLUTION AND LOWERED CONSENSUS POPS SLIGHTLY IN THE TUESDAY TIME FRAME. HIGH TEMPERATURES SHOULD RETURN TO MORE SEASONABLE VALUES IN THE MID TO UPPER 70S AS COOLER AIR FROM THE NORTH IS BROUGHT INTO THE CENTRAL PLAINS FROM THE TROUGH MOVING ACROSS THE UPPER MIDWEST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1051 PM MDT TUE SEP 22 2015 SHOWERS WILL CONTINUE TO MOVE ACROSS THE TAF SITES OVERNIGHT WITH DECREASING COVERAGE AT KGLD AS DISTURBANCE MOVES OUT OF THE AREA AROUND 09Z. BOUNDARY LAYER RH INCREASES TOWARD 12Z PRODUCING STRATUS ACROSS THE AREA. SOME FOG WILL BE POSSIBLE AT THE SITES, ESPECIALLY AT KMCK. THE STRATUS SHOULD BREAK UP BY LATE MORNING WITH MORE SHOWERS POSSIBLE IN THE AFTERNOON AND EVENING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...MK AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1056 PM MDT TUE SEP 22 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 211 PM MDT TUE SEP 22 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS A SERIES OF H7/H5 UPPER TROUGHS PROPAGATING THROUGH A MEAN SW FLOW ACROSS THE CENTRAL ROCKIES. THE NEAREST UPPER LOW IS NOW MOVING INTO THE SOUTHERN PART OF OUR CWA WITH PLUME OF RICH MID LEVEL MOISTURE SPREADING NORTH OUT OF SW KANSAS. PWATS AS INDICATED BY RAP ANALYSIS ARE NEARING 1.4-1.5 SOUTH OF OUR CWA. STEEP LOW AND MID LEVEL LAPSE RATES HAVE LED TO ISOLATED SHOWER/THUNDERSTORM DEVELOPMENT IN PROXIMITY TO STALLED FRONTAL ZONE ALONG I-70 IN COLORADO. THIS STALLED COLD FRONT EXTENDS NORTH INTO SW AND CENTRAL NEBRASKA WHERE HIGHER CINH HAS LIMITED CONVECTIVE INITIATION. THIS AFTERNOON-TONIGHT...ISOLATED TO SCATTERED THUNDERSTORM ACTIVITY WILL CONTINUE TO BE POSSIBLE AHEAD OF MAIN AREA OF LARGE SCALE FORCING (SOUTH OF TROUGH AXIS. AS THIS UPPER TROUGH SHIFTS NORTH SHOWERS AND THUNDERSTORM SHOULD SPREAD NORTH ALONG/EAST OF CO/KS STATE LINE. A SECOND UPPER LOW/STRONG LOBE OF VORTICITY WILL ROTATE THROUGH THE REGION TONIGHT AND GUIDANCE IS SHOWING A PARTICULARLY STRONG PRECIP SIGNAL WITH THIS SECONDARY UPPER LOW AROUND 06-09Z. BEST INSTABILITY QUICKLY DROPS OFF AFTER 00Z...HOWEVER STEEP MID LEVEL LAPSE RATES AND WEAK CAPE WILL AT LEAST SUPPORT A THREAT FOR EMBEDDED CONVECTION OVERNIGHT. ANOMALOUSLY HIGH PWATS...DEEP MOISTURE ADVECTION...AND CONTINUOUS SOUTH TO NORTH BUILDING/TRAINING OF SHOWERS/THUNDERSTORMS WILL SUPPORT POSSIBLE HEAVY RAIN WITH MANY LOCATIONS RECEIVING ONE HALF TO ONE INCH...POSSIBLY HIGHER. WEDNESDAY...UPPER LOW SHIFTS NORTHEAST AND SLOWS DOWN OVER CENTRAL NEBRASKA...ALLOWING FOR MOIST/WEAKLY UNSTABLE AIR MASS TO LINGER EAST OF STALLED FRONTAL ZONE. COLD POOL ALOFT WILL SUPPORT POSSIBLE SHOWER/THUNDERSTORM REDEVELOPMENT IN THE AFTERNOON...SO WHILE BEST LARGE SCALE FORCING IS NORTHEAST BY MIDDAY WE WILL CONTINUE TO SEE CHANCES THROUGH THE DAY...PARTICULARLY IN THE EAST. GUIDANCE IS SHOWING THE POTENTIAL FOR DRIER AIR TO ADVECT IN FROM THE WEST...SO LOCATIONS IN EASTERN COLORADO AND FAR WESTERN KANSAS MAY REMAIN DRY WEDNESDAY AFTERNOON. I SHOWED A DECREASING TREND IN COVERAGE FROM THE WEST TO THE EAST. HIGH TEMPS ARE TRICKY AS CLEARING/WAA IN THE WEST COULD SUPPORT MID TO UPPER 80S FOR HIGHS...WHILE PERSISTENT CLOUD COVER/SHOWERS EAST OF FRONTAL ZONE/SURFACE TROUGH WOULD HOLD HIGHS DOWN IN THE 70S. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 300 PM MDT TUE SEP 22 2015 MAIN FORECAST PROBLEM WILL BE CHANCES OF PRECIPITATION THROUGH FRIDAY. SATELLITE IS SHOWING AN AMPLIFIED PATTERN OVER THE PACIFIC WHICH THEN TRANSLATES TO A DEVELOPING TROUGH OVER THE WESTERN PORTION OF THE COUNTRY THEN RIDGE OVER THE CENTRAL PORTION WITH ANOTHER TROUGH OVER THE EASTERN PORTION. AT JET LEVEL...THE GFS/CANADIAN/ECMWF WERE STARTING OUT A LITTLE BETTER THAN THE NAM. AT MID LEVELS...THE GFS/CANADIAN WERE DOING A LITTLE BETTER THAN THE UKMET/ECMWF. THE SREF WAS DOING THE BEST ON THE SURFACE PATTERN. THE NAM/CANADIAN WAS DOING A LITTLE BETTER THAN THE GFS/SREF ON THE LOW LEVEL THERMAL FIELD. WEDNESDAY NIGHT...JET IS EAST AND SOUTH OF THE AREA. SLOW MOVING UPPER TROUGH WITH THE CLOSED OFF PORTION OVER CENTRAL NEBRASKA. THE TROUGH MOVES THROUGH VERY SLOWLY WITH THE TROUGH LINE NEAR THE EASTERN END OF THE FORECAST AREA. A COUPLE DIFFERENT SHORTWAVES ROTATE THROUGH...MAINLY ACROSS THE EAST...THROUGH THE NIGHT. SO KEPT THE HIGHEST POPS IN THE EASTERN END. THURSDAY/THURSDAY NIGHT...BEHAVIOR OF THE UPPER LOW BECOMES PROBLEMATIC DURING THIS TIME. EASTWARD PROGRESSION STOPS DURING THE DAY WITH IT SLOWLY SINKING SOUTH. AGAIN DIFFERENT SHORTWAVE TROUGHS ROTATE AROUND THE SYSTEM AND THROUGH THE AREA...MAINLY IN THE EAST...WITH THE UPPER SYSTEM CENTERED OVER SOUTHEAST NEBRASKA. VERY HARD TO TIME THESE OUT WITH DIFFERENT MODELS SHOWING DIFFERENT SCENARIOS. COLDER AIR ALOFT WITH THETA-E LAPSE RATES VERY LOW AND THE TQ INDEX SUPPORTIVE OF INSTABILITY SHOWERS. SO IT SHOULD NOT TAKE TOO MUCH TO GET SHOWERS GOING. SO AT THIS TIME KEPT SLIGHT CHANCE TO CHANCE POPS IN THE EASTERN PORTION. FRONT MOVES THROUGH IN THE MORNING. AM THINKING MAY NOT HAVE A LOT OF SUNSHINE DUE TO THE COLD POOL ALOFT. 850 MB TEMPERATURES SUPPORTIVE OF COOLER TEMPERATURES AND THAT ALONG WITH THE CLOUD COVER LOWERED THE TEMPERATURES. HOWEVER SOME GUIDANCE IS COOLER THAN WHAT I HAVE IN THERE. UPPER LOW THEN STARTS BACKING UP TOWARD THE WEST THROUGH THE NIGHT. THIS PUTS THE AREA IN THE NORTHWEST QUADRANT WITH THE POTENTIAL FOR WRAP AROUND TO OCCUR. FRONTOGENESIS AND NEGATIVE THETA-E LAPSE RATES SHOULD MAKE IT EASY FOR WHATEVER LIFT THERE IS TO START THE PRECIPITATION. MODELS DO SHOW LIGHT QPF CONTINUING. FRIDAY...UPPER LOW CONTINUES TO MOVE TOWARD THE WEST AND A LITTLE TO THE SOUTH THROUGH THE DAY. RATHER STRONG SHORTWAVE/FRONTOGENESIS ROTATING AROUND THE NORTH AND WEST SIDES OF THE SYSTEM. AGAIN COLD POOL REMAINS ON TOP OF US WITH THE NEGATIVE THETA-E LAPSE RATES IN PLACE AND THE TQ INDEX SUPPORT OF INSTABILITY SHOWERS. PROBLEM IS THE MODELS ARE NOT SHOWING A LOT OF MOISTURE. HOWEVER AM NOT SURE THAT THE MODELS ARE TOTALLY CATCHING HIS UNUSUAL SCENARIO. SO KEPT A SLIGHT CHANCE THROUGH THE DAY. WITH THE UPPER LOW SINKING ON TOP OF US...MORE COLD AIR MOVING INTO THE AREA AND THE CLOUD COVER...COOLED THE TEMPERATURES A LITTLE BIT FROM WHERE THEY WERE. FRIDAY NIGHT THROUGH TUESDAY...AFTER ABOUT A DAY INTO THIS PERIOD THE MODELS...DETERMINISTIC/ENSEMBLES...START DIVERGING SIGNIFICANTLY. IN FACT BY THE END OF THE PERIOD THE ECMWF AND GFS ARE COMPLETELY OUT OF PHASE. SO CONFIDENCE IN THE OUTCOME OF THIS IS LOW. CONSIDERING THE CURRENT FLOW PATTERN WOULD BELIEVE THAT THE AMPLIFIED PATTERN SHOULD CONTINUE. SAYING THAT THE GFS IS THE BIG OUTLIER. THE ECMWF AND TO A LESSER DEGREE THE CANADIAN ARE MORE AMPLIFIED WITH THE CANADIAN ACTUALLY IN THE MIDDLE OF THE SOLUTION FIELD. SAYING ALL THAT...THE WPC MANUAL PROGS TAKE THAT INTO ACCOUNT AND SIDE IN THAT DIRECTION. SO HAVE LITTLE CONFIDENCE IN MAKING ANY SIGNIFICANT CHANGES TO WHAT THE INIT...WHICH IS DRY THROUGH THE PERIOD...GAVE. SO MADE NO CHANGES OVERALL TO WHAT I WAS GIVEN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1051 PM MDT TUE SEP 22 2015 SHOWERS WILL CONTINUE TO MOVE ACROSS THE TAF SITES OVERNIGHT WITH DECREASING COVERAGE AT KGLD AS DISTURBANCE MOVES OUT OF THE AREA AROUND 09Z. BOUNDARY LAYER RH INCREASES TOWARD 12Z PRODUCING STRATUS ACROSS THE AREA. SOME FOG WILL BE POSSIBLE AT THE SITES, ESPECIALLY AT KMCK. THE STRATUS SHOULD BREAK UP BY LATE MORNING WITH MORE SHOWERS POSSIBLE IN THE AFTERNOON AND EVENING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...BULLER AVIATION...FS
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1127 PM EDT THU SEP 24 2015 .UPDATE... ISSUED AT 1125 PM EDT THU SEP 24 2015 HOURLY TEMPERATURE AND DEWPOINT GRIDS HAVE BEEN UPDATED...BUT NO OTHER CHANGES WERE NEEDED ATTM. SHOWERS HAVE MEASURED AS FAR WEST AS THE INTERSTATE 81 CORRIDOR IN TN NEAR KTRI. GUIDANCE CONTINUES TO INDICATE THAT A BAND OF SHOWERS WILL SPREAD INTO THE AREA TOWARD DAWN. UPDATE ISSUED AT 850 PM EDT THU SEP 24 2015 A BROAD MID AND UPPER LEVEL LOW PRESSURE SYSTEM CONTINUES TO SPIN ACROSS THE SOUTHEASTERN CONUS. THIS IS BRINGING ATLANTIC MOISTURE WEST AND NORTHWEST ACROSS THE SOUTHEASTERN STATES AND INTO THE APPALACHIANS. RADAR RETURNS ARE GRADUALLY SPREADING ACROSS THE BLUE RIDGE AND INTO THE SMOKY MOUNTAINS AND NE TN MOUNTAINS. MOST OF THE MEASURABLE RAIN SO FAR HAS BEEN EAST OF THE BLUE RIDGE IN NC. MEANWHILE...A SFC AREA OF LOW PRESSURE WAS OFF THE SOUTHEAST US COAST WHILE AN AREA OF HIGH PRESSURE WAS CENTERED WELL NORTH OF THE AREA LEADING TO EASTERLY FLOW AT HIGHER ELEVATIONS NEAR THE VA BORDER AND NORTHEASTERLY FLOW IN MOST LOCATIONS. RECENT CONSSHORT AND HRRR GUIDANCE POINTS TOWARD A BIT SLOWER ARRIVAL OF SHOWERS INTO EASTERN KY AND RADAR TRENDS SUPPORT THIS. THE LEADING EDGE OF THE SHOWERS WILL LIKELY NOT BE MUCH MORE THAN SPRINKLES AS THE LOW LEVEL FLOW IS ACROSS THE APPALACHIANS AND HAS A DOWNSLOPE COMPONENT. HOWEVER...MOISTURE WILL INCREASE SUFFICIENTLY FOR SHOWERS WITH MEASURABLE RAIN TO SPREAD ACROSS SOUTHEAST KY TOWARD DAWN. HOURLY POPS HAVE BEEN ADJUSTED ACCORDINGLY WITH HOURLY DEWPOINTS AND TEMPERATURES FRESHENED UP BASED ON RECENT OBSERVATIONS. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 340 PM EDT THU SEP 24 2015 18Z SFC ANALYSIS SHOWS HIGH PRESSURE TO THE NORTH AND EAST OF KENTUCKY WHILE LOW PRESSURE IS FOUND OFF THE SOUTHEAST COAST. THIS LOW HAS BEEN RESPONSIBLE FOR SOME VERY LIMITED MID AND HIGH LEVEL CLOUDS SPREADING INTO KENTUCKY FROM THE SOUTHEAST. EXCEPT FOR PERHAPS THE FAR EAST...AMPLE SUNSHINE DOMINATED EAST KENTUCKY TODAY HELPING TO SEND TEMPERATURES UP INTO THE LOWER 80S FOR MOST PLACES. DEWPOINTS FELL INTO THE LOWER 50S DUE TO SOME DRY AIR MIX DOWN THIS AFTERNOON. WINDS...MEANWHILE...HAVE BEEN FROM THE NORTHEAST AT 5 TO 10 KTS TODAY. THE MODELS ARE IN GOOD AGREEMENT ALOFT...AS THEY HAVE BEEN FOR MUCH OF THIS WEEK IN THE SHORT TERM. THEY ALL DEPICT AN UPPER LOW...IN THE MIDST OF GENERAL HIGH HEIGHTS THROUGH MUCH OF THE NATION...SLOWLY DEVELOPING OVER THE SOUTHEAST. THIS LOW WILL CLOSE OFF AND DRIFT NORTHWEST WITH TIME...REACHING THE MID TENNESSEE VALLEY BY 12Z SATURDAY. PLENTY OF ENERGY WILL SPIN THROUGH THE HEART OF THIS LOW AS IT IMPACT OUR AREA LATER TONIGHT AND THROUGH THE REST OF THE PERIOD. THE ECMWF IS A BIT STRONGER WITH THIS LOW THAN THE OTHER MODELS WITH THE NAM12 IN THE MIDDLE OF THE CONSENSUS. GIVEN THE GENERAL MODEL AGREEMENT HAVE FAVORED THE HIGHER RESOLUTION NAM12 AND HRRR FOR WEATHER DETAILS. SENSIBLE WEATHER WILL FEATURE A DRY AND MOSTLY CLEAR EVENING ACROSS EAST KENTUCKY. CLOUDS WILL MOVE IN FROM THE EAST AND THICKEN DURING THE NIGHT WITH SHOWERS POTENTIALLY ARRIVING BEFORE DAWN IN THE FAR EAST. THIS AREA OF PRECIPITATION WILL THEN BUILD QUICKLY WEST THROUGH FRIDAY MORNING WITH MUCH OF THE CWA COVERED BY MIDDAY. THE EXCEPTION COULD BE FAR NORTHERN PARTS OF EAST KENTUCKY. SEVERAL ROUNDS OF SHOWERS ARE EXPECTED THROUGH THE AREA INTO SATURDAY WITH A DRIFT TO THE NORTH ANTICIPATED FOR THE DEEPER MOISTURE LATE IN THE PERIOD. POCKETS OF HEAVIER PCPN WILL BE POSSIBLE...BUT IN GENERAL BETWEEN A QUARTER AND A HALF OF AN INCH OF RAIN CAN BE EXPECTED FROM LATE TONIGHT THROUGH SATURDAY MORNING. TEMPERATURES WILL BE MORE UNIFORM WITH THE RAIN FRIDAY AND FRIDAY NIGHT...THOUGH THIS EVENING WE WILL STILL LIKELY SEE A RIDGE TO VALLEY SPLIT DEVELOP BEFORE THE THICKER AND LOWER CLOUDS MOVE IN FROM THE SOUTHEAST. AGAIN USED THE SHORTBLEND INITIALLY FOR TEMPERATURES AND DEWPOINTS...INTO THE FIRST PART OF THE DAY FRIDAY WITH THE SUPERBLEND USED FROM THAT POINT THROUGH THE REST OF THE PERIOD. DID MAKE SOME MINOR...TERRAIN BASED...ADJUSTMENTS TO THE TEMPERATURES THIS EVENING. AS FOR POPS...ENDED UP SIMILAR TO A BLEND OF THE MAV AND MET MOS THROUGH THE PERIOD. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 343 PM EDT THU SEP 24 2015 UPPER LEVEL LOW THAT HAS BEEN SPINNING NEAR THE FAR SOUTHEAST WILL SLOWLY RETROGRADE NORTHWEST THROUGH THE PERIOD. BEFORE EVENTUALLY BECOMING DEFUSE BY EARLY NEXT WEEK. HOWEVER MODELS BECOME MUCH MORE DIVERGENT THROUGH THE NEXT WEEK ESPECIALLY IN RELATION TO THE SURFACE. AT THE SURFACE THE PERIOD BEGINS WITH HIGH PRESSURE PARKED ACROSS NEW ENGLAND...MEAN WHILE A SURFACE TROUGH MOVES ACROSS THE REGION. BETTER CHANCES OF PRECIP WILL BE EARLY ON SAT WITH CHANCES WAINING THROUGH THE DAY. NOW STUCK CLOSER TO BLEND OVERALL THROUGH THE LONG TERM PERIOD FOR CONSISTENCY...BUT MAY BE A BIT OVERDONE WITH GFS SEEMING TO BE MORE EXAGGERATE PRECIP THROUGH THE PERIOD COMPARED WITH ECMWF/CANADIAN. PERHAPS THE BETTER DAY FOR PRECIP CHANCES WOULD BE AS WE MOVE INTO WED WITH SOME TROUGHING AND LOWER HEIGHTS. THEN TRENDING DRIER OVERALL AS WE MOVE INTO THURS. HAVE STUCK WITH RAIN SHOWERS AT THIS POINT GIVEN THE TIME OF YEAR AND MODEL SOUNDINGS SHOWING MEAGER INSTABILITY SIGNALS...HOWEVER BETTER CHANCES IF ANY OF THUNDER WOULD BE MID WEEK. OVERALL TEMPS THROUGH THE PERIOD WILL REMAIN NEARER NORMAL. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 825 PM EDT THU SEP 24 2015 HIGH PRESSURE OFF TO OUR NORTH WILL KEEP VFR CONDITIONS THROUGH AT LEAST THE 6Z TO 12Z PERIOD...EVEN ACROSS THE FAR SOUTHEAST PART OF THE CWA. HOWEVER...THE FIRST SIGNS OF AN UPPER LEVEL BEGINNING TO AFFECT THE REGION CAN BE SEEN IN THE HIGH CLOUDS AND IN SOME CASES MID LEVEL CLOUDS OVERHEAD. BETWEEN 8Z AND 18Z...INCREASING MOISTURE AND SHOWERS WILL LEAD TO GRADUAL SATURATION FROM THE TOP DOWN AND MVFR DEVELOPING FIRST NEAR THE VA BORDER AND THEN SPREADING GRADUALLY NORTH AND WEST. THE LOW LEVELS ACROSS THE SOUTHEASTERN PART OF THE CWA SHOULD FURTHER SATURATE FOR SOME CIGS BELOW 2KFT PRIOR TO THE END OF THE PERIOD. WINDS WILL GENERALLY REMAIN LIGHT AND VARIABLE THROUGH THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...DJ AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
859 PM EDT THU SEP 24 2015 .UPDATE... ISSUED AT 850 PM EDT THU SEP 24 2015 A BROAD MID AND UPPER LEVEL LOW PRESSURE SYSTEM CONTINUES TO SPIN ACROSS THE SOUTHEASTERN CONUS. THIS IS BRINGING ATLANTIC MOISTURE WEST AND NORTHWEST ACROSS THE SOUTHEASTERN STATES AND INTO THE APPALACHIANS. RADAR RETURNS ARE GRADUALLY SPREADING ACROSS THE BLUE RIDGE AND INTO THE SMOKY MOUNTAINS AND NE TN MOUNTAINS. MOST OF THE MEASURABLE RAIN SO FAR HAS BEEN EAST OF THE BLUE RIDGE IN NC. MEANWHILE...A SFC AREA OF LOW PRESSURE WAS OFF THE SOUTHEAST US COAST WHILE AN AREA OF HIGH PRESSURE WAS CENTERED WELL NORTH OF THE AREA LEADING TO EASTERLY FLOW AT HIGHER ELEVATIONS NEAR THE VA BORDER AND NORTHEASTERLY FLOW IN MOST LOCATIONS. RECENT CONSSHORT AND HRRR GUIDANCE POINTS TOWARD A BIT SLOWER ARRIVAL OF SHOWERS INTO EASTERN KY AND RADAR TRENDS SUPPORT THIS. THE LEADING EDGE OF THE SHOWERS WILL LIKELY NOT BE MUCH MORE THAN SPRINKLES AS THE LOW LEVEL FLOW IS ACROSS THE APPALACHIANS AND HAS A DOWNSLOPE COMPONENT. HOWEVER...MOISTURE WILL INCREASE SUFFICIENTLY FOR SHOWERS WITH MEASURABLE RAIN TO SPREAD ACROSS SOUTHEAST KY TOWARD DAWN. HOURLY POPS HAVE BEEN ADJUSTED ACCORDINGLY WITH HOURLY DEWPOINTS AND TEMPERATURES FRESHENED UP BASED ON RECENT OBSERVATIONS. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 340 PM EDT THU SEP 24 2015 18Z SFC ANALYSIS SHOWS HIGH PRESSURE TO THE NORTH AND EAST OF KENTUCKY WHILE LOW PRESSURE IS FOUND OFF THE SOUTHEAST COAST. THIS LOW HAS BEEN RESPONSIBLE FOR SOME VERY LIMITED MID AND HIGH LEVEL CLOUDS SPREADING INTO KENTUCKY FROM THE SOUTHEAST. EXCEPT FOR PERHAPS THE FAR EAST...AMPLE SUNSHINE DOMINATED EAST KENTUCKY TODAY HELPING TO SEND TEMPERATURES UP INTO THE LOWER 80S FOR MOST PLACES. DEWPOINTS FELL INTO THE LOWER 50S DUE TO SOME DRY AIR MIX DOWN THIS AFTERNOON. WINDS...MEANWHILE...HAVE BEEN FROM THE NORTHEAST AT 5 TO 10 KTS TODAY. THE MODELS ARE IN GOOD AGREEMENT ALOFT...AS THEY HAVE BEEN FOR MUCH OF THIS WEEK IN THE SHORT TERM. THEY ALL DEPICT AN UPPER LOW...IN THE MIDST OF GENERAL HIGH HEIGHTS THROUGH MUCH OF THE NATION...SLOWLY DEVELOPING OVER THE SOUTHEAST. THIS LOW WILL CLOSE OFF AND DRIFT NORTHWEST WITH TIME...REACHING THE MID TENNESSEE VALLEY BY 12Z SATURDAY. PLENTY OF ENERGY WILL SPIN THROUGH THE HEART OF THIS LOW AS IT IMPACT OUR AREA LATER TONIGHT AND THROUGH THE REST OF THE PERIOD. THE ECMWF IS A BIT STRONGER WITH THIS LOW THAN THE OTHER MODELS WITH THE NAM12 IN THE MIDDLE OF THE CONSENSUS. GIVEN THE GENERAL MODEL AGREEMENT HAVE FAVORED THE HIGHER RESOLUTION NAM12 AND HRRR FOR WEATHER DETAILS. SENSIBLE WEATHER WILL FEATURE A DRY AND MOSTLY CLEAR EVENING ACROSS EAST KENTUCKY. CLOUDS WILL MOVE IN FROM THE EAST AND THICKEN DURING THE NIGHT WITH SHOWERS POTENTIALLY ARRIVING BEFORE DAWN IN THE FAR EAST. THIS AREA OF PRECIPITATION WILL THEN BUILD QUICKLY WEST THROUGH FRIDAY MORNING WITH MUCH OF THE CWA COVERED BY MIDDAY. THE EXCEPTION COULD BE FAR NORTHERN PARTS OF EAST KENTUCKY. SEVERAL ROUNDS OF SHOWERS ARE EXPECTED THROUGH THE AREA INTO SATURDAY WITH A DRIFT TO THE NORTH ANTICIPATED FOR THE DEEPER MOISTURE LATE IN THE PERIOD. POCKETS OF HEAVIER PCPN WILL BE POSSIBLE...BUT IN GENERAL BETWEEN A QUARTER AND A HALF OF AN INCH OF RAIN CAN BE EXPECTED FROM LATE TONIGHT THROUGH SATURDAY MORNING. TEMPERATURES WILL BE MORE UNIFORM WITH THE RAIN FRIDAY AND FRIDAY NIGHT...THOUGH THIS EVENING WE WILL STILL LIKELY SEE A RIDGE TO VALLEY SPLIT DEVELOP BEFORE THE THICKER AND LOWER CLOUDS MOVE IN FROM THE SOUTHEAST. AGAIN USED THE SHORTBLEND INITIALLY FOR TEMPERATURES AND DEWPOINTS...INTO THE FIRST PART OF THE DAY FRIDAY WITH THE SUPERBLEND USED FROM THAT POINT THROUGH THE REST OF THE PERIOD. DID MAKE SOME MINOR...TERRAIN BASED...ADJUSTMENTS TO THE TEMPERATURES THIS EVENING. AS FOR POPS...ENDED UP SIMILAR TO A BLEND OF THE MAV AND MET MOS THROUGH THE PERIOD. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 343 PM EDT THU SEP 24 2015 UPPER LEVEL LOW THAT HAS BEEN SPINNING NEAR THE FAR SOUTHEAST WILL SLOWLY RETROGRADE NORTHWEST THROUGH THE PERIOD. BEFORE EVENTUALLY BECOMING DEFUSE BY EARLY NEXT WEEK. HOWEVER MODELS BECOME MUCH MORE DIVERGENT THROUGH THE NEXT WEEK ESPECIALLY IN RELATION TO THE SURFACE. AT THE SURFACE THE PERIOD BEGINS WITH HIGH PRESSURE PARKED ACROSS NEW ENGLAND...MEAN WHILE A SURFACE TROUGH MOVES ACROSS THE REGION. BETTER CHANCES OF PRECIP WILL BE EARLY ON SAT WITH CHANCES WAINING THROUGH THE DAY. NOW STUCK CLOSER TO BLEND OVERALL THROUGH THE LONG TERM PERIOD FOR CONSISTENCY...BUT MAY BE A BIT OVERDONE WITH GFS SEEMING TO BE MORE EXAGGERATE PRECIP THROUGH THE PERIOD COMPARED WITH ECMWF/CANADIAN. PERHAPS THE BETTER DAY FOR PRECIP CHANCES WOULD BE AS WE MOVE INTO WED WITH SOME TROUGHING AND LOWER HEIGHTS. THEN TRENDING DRIER OVERALL AS WE MOVE INTO THURS. HAVE STUCK WITH RAIN SHOWERS AT THIS POINT GIVEN THE TIME OF YEAR AND MODEL SOUNDINGS SHOWING MEAGER INSTABILITY SIGNALS...HOWEVER BETTER CHANCES IF ANY OF THUNDER WOULD BE MID WEEK. OVERALL TEMPS THROUGH THE PERIOD WILL REMAIN NEARER NORMAL. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 825 PM EDT THU SEP 24 2015 HIGH PRESSURE OFF TO OUR NORTH WILL KEEP VFR CONDITIONS THROUGH AT LEAST THE 6Z TO 12Z PERIOD...EVEN ACROSS THE FAR SOUTHEAST PART OF THE CWA. HOWEVER...THE FIRST SIGNS OF AN UPPER LEVEL BEGINNING TO AFFECT THE REGION CAN BE SEEN IN THE HIGH CLOUDS AND IN SOME CASES MID LEVEL CLOUDS OVERHEAD. BETWEEN 8Z AND 18Z...INCREASING MOISTURE AND SHOWERS WILL LEAD TO GRADUAL SATURATION FROM THE TOP DOWN AND MVFR DEVELOPING FIRST NEAR THE VA BORDER AND THEN SPREADING GRADUALLY NORTH AND WEST. THE LOW LEVELS ACROSS THE SOUTHEASTERN PART OF THE CWA SHOULD FURTHER SATURATE FOR SOME CIGS BELOW 2KFT PRIOR TO THE END OF THE PERIOD. WINDS WILL GENERALLY REMAIN LIGHT AND VARIABLE THROUGH THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...DJ AVIATION...JP
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
120 PM EDT WED SEP 23 2015 ...Updated Aviation Discussion... ...Forecast Update... Issued at 820 AM EDT Wed Sep 23 2015 Another mostly clear start to the day. Rivers look clean and any morning fog has cleared out. Will remove morning wording for the fog in a zone update. Otherwise, bumped temperature forecast up a little. Readings were a couple degrees above what we had forecasted yesterday, so basically went with a persistence forecast from yesterday, calling for readings within a degree of yesterday`s highs. .SHORT TERM (Now through Thursday)... Issued at 250 AM EDT Wed Sep 23 2015 The main forecast challenge early this morning is fog development. While the 0Z NAM and CIRA-SIMWRF-FOG indicate some patchy dense fog may form closer to sunrise over portions of east central KY, the 5Z HRRR does not. Since the HRRR seems to have the better handle on fog in the region (south central IL) and dewpt depressions are still quite large (4-6 degrees) in some spots with no fog development noted yet in our area, will pull back on the fog mention to patchy and continue to monitor. Other than that, sfc high pressure and weak ridging aloft will remain in control of the region providing for mostly clear skies and pleasant temps. Highs today should range from 79-84. Tonight`s lows will vary through the 50s. Thurs looks to be slightly warmer than today with highs ranging from 80-86. .LONG TERM (Thursday night through Tuesday)... Issued at 302 AM EDT Wed Sep 23 2015 The main forecast concern in the long term is precipitation chances this weekend. Friday into Sunday the synoptic pattern will feature a weak upper level low retrograding westward from the NC coast. 23.00z guidance is in reasonable agreement showing higher moisture with this feature arriving late Friday with mid/high clouds on the increase east of I- 65. An east-west cross section through the area shows that the deeper moisture with some lift is expected mainly across south- central KY. The weak upper lift combined with a more moist air mass characterized by PWATS approaching 1.5 inches may spark isolated to scattered showers late Friday night into Saturday across south- central KY. The increased cloud cover is likely to keep Saturday morning readings in the low 60s and highs in the upper 70s to near 80. A stray, pop-up shower can`t be ruled out further north along the Ohio River and into southern Indiana Saturday and Sunday, but expected coverage and chances are rather low at this time. Upper ridging begins to build across the region early next week as a northern Plains trough takes shape. This will pull warmer air northward into region Monday into Tuesday where highs could push the mid 80s in places with mild mornings in the 60s. There is reasonable consensus between the forecast models at this time showing a frontal passage mid-week bringing a chance of showers or storms and then cooler Canadian air in its wake around the first of October. && .AVIATION (18Z TAF Update)... Issued at 120 PM EDT Wed Sep 23 2015 High pressure and weak upper level ridging will remain in control of the region. This should keep the terminals VFR this period, with the exception of brief light fog at KBWG again Thursday morning. Otherwise, expect a steady NE wind and a few cu around 3-5K feet this afternoon and starting up again late Thursday morning. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........RJS Short Term.....AMS Long Term......ZBT Aviation.......RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
822 AM EDT WED SEP 23 2015 ...Forecast Update... Issued at 820 AM EDT Wed Sep 23 2015 Another mostly clear start to the day. Rivers look clean and any morning fog has cleared out. Will remove morning wording for the fog in a zone update. Otherwise, bumped temperature forecast up a little. Readings were a couple degrees above what we had forecasted yesterday, so basically went with a persistence forecast from yesterday, calling for readings within a degree of yesterday`s highs. .SHORT TERM (Now through Thursday)... Issued at 250 AM EDT Wed Sep 23 2015 The main forecast challenge early this morning is fog development. While the 0Z NAM and CIRA-SIMWRF-FOG indicate some patchy dense fog may form closer to sunrise over portions of east central KY, the 5Z HRRR does not. Since the HRRR seems to have the better handle on fog in the region (south central IL) and dewpt depressions are still quite large (4-6 degrees) in some spots with no fog development noted yet in our area, will pull back on the fog mention to patchy and continue to monitor. Other than that, sfc high pressure and weak ridging aloft will remain in control of the region providing for mostly clear skies and pleasant temps. Highs today should range from 79-84. Tonight`s lows will vary through the 50s. Thurs looks to be slightly warmer than today with highs ranging from 80-86. .LONG TERM (Thursday night through Tuesday)... Issued at 302 AM EDT Wed Sep 23 2015 The main forecast concern in the long term is precipitation chances this weekend. Friday into Sunday the synoptic pattern will feature a weak upper level low retrograding westward from the NC coast. 23.00z guidance is in reasonable agreement showing higher moisture with this feature arriving late Friday with mid/high clouds on the increase east of I- 65. An east-west cross section through the area shows that the deeper moisture with some lift is expected mainly across south- central KY. The weak upper lift combined with a more moist air mass characterized by PWATS approaching 1.5 inches may spark isolated to scattered showers late Friday night into Saturday across south- central KY. The increased cloud cover is likely to keep Saturday morning readings in the low 60s and highs in the upper 70s to near 80. A stray, pop-up shower can`t be ruled out further north along the Ohio River and into southern Indiana Saturday and Sunday, but expected coverage and chances are rather low at this time. Upper ridging begins to build across the region early next week as a northern Plains trough takes shape. This will pull warmer air northward into region Monday into Tuesday where highs could push the mid 80s in places with mild mornings in the 60s. There is reasonable consensus between the forecast models at this time showing a frontal passage mid-week bringing a chance of showers or storms and then cooler Canadian air in its wake around the first of October. && .AVIATION (12Z TAF Update)... Issued at 645 AM EDT Wed Sep 23 2015 High pressure and weak upper level ridging will remain in control of the region. This should keep the terminals VFR this period, with the exception of brief light fog at KBWG this morning. Otherwise, expect a steady NE wind and a few cu around 3-4K feet this afternoon. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........RJS Short Term.....AMS Long Term......ZBT Aviation.......AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
640 AM EDT WED SEP 23 2015 ...Updated Aviation Discussion... .SHORT TERM (Now through Thursday)... Issued at 250 AM EDT Wed Sep 23 2015 The main forecast challenge early this morning is fog development. While the 0Z NAM and CIRA-SIMWRF-FOG indicate some patchy dense fog may form closer to sunrise over portions of east central KY, the 5Z HRRR does not. Since the HRRR seems to have the better handle on fog in the region (south central IL) and dewpt depressions are still quite large (4-6 degrees) in some spots with no fog development noted yet in our area, will pull back on the fog mention to patchy and continue to monitor. Other than that, sfc high pressure and weak ridging aloft will remain in control of the region providing for mostly clear skies and pleasant temps. Highs today should range from 79-84. Tonight`s lows will vary through the 50s. Thurs looks to be slightly warmer than today with highs ranging from 80-86. .LONG TERM (Thursday night through Tuesday)... Issued at 302 AM EDT Wed Sep 23 2015 The main forecast concern in the long term is precipitation chances this weekend. Friday into Sunday the synoptic pattern will feature a weak upper level low retrograding westward from the NC coast. 23.00z guidance is in reasonable agreement showing higher moisture with this feature arriving late Friday with mid/high clouds on the increase east of I- 65. An east-west cross section through the area shows that the deeper moisture with some lift is expected mainly across south- central KY. The weak upper lift combined with a more moist air mass characterized by PWATS approaching 1.5 inches may spark isolated to scattered showers late Friday night into Saturday across south- central KY. The increased cloud cover is likely to keep Saturday morning readings in the low 60s and highs in the upper 70s to near 80. A stray, pop-up shower can`t be ruled out further north along the Ohio River and into southern Indiana Saturday and Sunday, but expected coverage and chances are rather low at this time. Upper ridging begins to build across the region early next week as a northern Plains trough takes shape. This will pull warmer air northward into region Monday into Tuesday where highs could push the mid 80s in places with mild mornings in the 60s. There is reasonable consensus between the forecast models at this time showing a frontal passage mid-week bringing a chance of showers or storms and then cooler Canadian air in its wake around the first of October. && .AVIATION (12Z TAF Update)... Issued at 639 AM EDT Wed Sep 23 2015 High pressure and weak upper level ridging will remain in control of the region. This should keep the terminals VFR this period, with the exception of brief light fog at KBWG this morning. Otherwise, expect a steady NE wind and a few cu around 3-4K feet this afternoon. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Short Term........AMS Long Term.........ZBT Aviation..........AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
303 AM EDT WED SEP 23 2015 .SHORT TERM (Now through Thursday)... Issued at 250 AM EDT Wed Sep 23 2015 The main forecast challenge early this morning is fog development. While the 0Z NAM and CIRA-SIMWRF-FOG indicate some patchy dense fog may form closer to sunrise over portions of east central KY, the 5Z HRRR does not. Since the HRRR seems to have the better handle on fog in the region (south central IL) and dewpt depressions are still quite large (4-6 degrees) in some spots with no fog development noted yet in our area, will pull back on the fog mention to patchy and continue to monitor. Other than that, sfc high pressure and weak ridging aloft will remain in control of the region providing for mostly clear skies and pleasant temps. Highs today should range from 79-84. Tonight`s lows will vary through the 50s. Thurs looks to be slightly warmer than today with highs ranging from 80-86. .LONG TERM (Thursday night through Tuesday)... Issued at 302 AM EDT Wed Sep 23 2015 The main forecast concern in the long term is precipitation chances this weekend. Friday into Sunday the synoptic pattern will feature a weak upper level low retrograding westward from the NC coast. 23.00z guidance is in reasonable agreement showing higher moisture with this feature arriving late Friday with mid/high clouds on the increase east of I- 65. An east-west cross section through the area shows that the deeper moisture with some lift is expected mainly across south- central KY. The weak upper lift combined with a more moist air mass characterized by PWATS approaching 1.5 inches may spark isolated to scattered showers late Friday night into Saturday across south- central KY. The increased cloud cover is likely to keep Saturday morning readings in the low 60s and highs in the upper 70s to near 80. A stray, pop-up shower can`t be ruled out further north along the Ohio River and into southern Indiana Saturday and Sunday, but expected coverage and chances are rather low at this time. Upper ridging begins to build across the region early next week as a northern Plains trough takes shape. This will pull warmer air northward into region Monday into Tuesday where highs could push the mid 80s in places with mild mornings in the 60s. There is reasonable consensus between the forecast models at this time showing a frontal passage mid-week bringing a chance of showers or storms and then cooler Canadian air in its wake around the first of October. && .AVIATION (06Z TAF Update)... Issued at 110 AM EDT Wed Sep 23 2015 High pressure will remain in control of the region with upper level ridging moving in from the west. This should keep the terminals VFR this period, with the exception of brief light fog at KBWG and perhaps KLEX around daybreak this morning. Otherwise, expect a steady NE wind and a few cu around 3-4K feet this afternoon. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Short Term........AMS Long Term.........ZBT Aviation..........AMS
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
217 AM EDT WED SEP 23 2015 .UPDATE... ISSUED AT 217 AM EDT WED SEP 23 2015 FRESHENED UP THE HOURLY TEMPERATURES AND DEW POINTS BASED ON THE LATEST TRENDS IN OBSERVATIONS...OTHERWISE THE FORECAST REMAINS ON TRACK. UPDATE ISSUED AT 1100 PM EDT TUE SEP 22 2015 HIGH PRESSURE CONTINUES TO DOMINATE THE WEATHER ACROSS THE REGION. A FEW LOCATIONS ACROSS EAST CENTRAL KY AND THE BLUEGRASS REGION AS WELL AS VALLEYS IN THE BIG SANDY REGION WERE RUNNING A BIT COOLER THAN THE PREVIOUS FORECAST. OVERNIGHT LOWS WERE ADJUSTED DOWN A DEGREE OR TWO IN SOME LOCATIONS IN THE NW PART OF THE CWA...WHILE THE HOURLY TEMPERATURE AND DEWPOINT GRIDS WERE FINE TUNED AS WELL. UPDATE ISSUED AT 815 PM EDT TUE SEP 22 2015 HOURLY TEMPERATURE AND DEWPOINT GRIDS HAVE BEEN FRESHENED UP BASED ON RECENT OBSERVATIONS. OTHERWISE...NO CHANGES WERE NEEDED AT THIS TIME AS HIGH PRESSURE REMAINS IN CONTROL. SOME PATCHY DENSE VALLEY FOG IS AGAIN ANTICIPATED LATE TONIGHT. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 340 PM EDT TUE SEP 22 2015 18Z SFC ANALYSIS SHOWS HIGH PRESSURE IN PLACE OVER THE OHIO VALLEY AND NORTHEAST. THERE IS A WEAK LEE SIDE LOW NEAR THE SPINE OF THE APPALACHIANS AND THIS HAS BEEN ENOUGH IN THE PAST COUPLE OF DAYS TO GENERATE SOME LIGHT SHOWERS ON THE OTHER SIDE OF OUR BORDER. NOTHING HAS POPPED UP ON RADAR SO FAR...THOUGH...AND THE CU FIELD IS RATHER SPARSE. AMPLE SUNSHINE BETWEEN THE CU ALLOWED TEMPERATURES TO PEAK IN THE MID TO UPPER 70S THROUGH THE AREA THIS AFTERNOON WITH A FEW 80 DEGREE REPORTS NOTED. DEWPOINTS... MEANWHILE...ARE IN THE MID TO UPPER 50S WITH A FEW LOW 60S SEEN IN THE EAST. WINDS HAVE GENERALLY BEEN OUT OF THE NORTHEAST AT 5 TO 10 KT THIS AFTERNOON. THE MODELS ARE IN GOOD AGREEMENT ALOFT AS THEY ALL DEPICT A BENIGN PATTERN CONSISTING OF FAST FLOW NORTH OF THE U.S. CANADIAN BORDER AND GENERALLY HIGH HEIGHTS THROUGH THE OHIO VALLEY. THERE WILL BE A SMATTERING OF ENERGY EAST OF KENTUCKY ASSOCIATED WITH A WEAKENING UPPER LEVEL LOW OVER THE SOUTHEAST PARTS OF THE NATION. EVEN A SHORTWAVE TROUGH COMING OUT OF THE NORTHERN PLAINS LATER WEDNESDAY WILL WEAKEN AND SLOW WITH ITS APPROACH TOWARD THE MISSISSIPPI RIVER. AS SUCH...PERSISTENCE WILL CONTINUE TO WIN THE DAY. GIVEN THE MODEL AGREEMENT AND LACK OF ANY SIGNIFICANT FEATURES WILL FAVOR THE HIGHER RESOLUTION HRRR AND NAM12 MODELS FOR WX SPECIFICS IN A REGIME OF PERSISTENCE. SENSIBLE WEATHER WILL FEATURE MORE OF THE SAME IN THIS STAGNANT PATTERN. TEMPERATURES OVERNIGHT WILL FALL TO VALUES JUST ABOVE LAST NIGHT/S LOWS. EXPECT FOG TO DEVELOP THROUGH THE NIGHT WITH LOCALLY DENSE PATCHES TOWARD DAWN...ESPECIALLY NEAR RIVERS AND LAKES. THIS FOG WILL BURN OFF BY 14Z WITH ANOTHER PARTLY TO MOSTLY SUNNY DAY AS TEMPERATURES CLIMB A COUPLE OF DEGREES HIGHER THAN TODAY. A SIMILAR PATTERN CAN BE ANTICIPATED ON WEDNESDAY NIGHT WITH READINGS AGAIN A NOTCH MILDER BUT WITH SIMILAR AMOUNTS OF LATE NIGHT FOG. FOR TEMPERATURES AND DEWPOINTS...USED THE SHORTBLEND MODEL GUIDANCE AS A STARTING POINT THROUGH THE BULK OF THE NIGHT BEFORE FAVORING THE SUPERBLEND FOR THE REST OF THE SHORT TERM PORTION OF THE FORECAST. DID MAKE SOME SIGNIFICANT ADJUSTMENTS TO THE NIGHT TIME TEMPERATURES TO BETTER CAPTURE THE EFFECTS OF AN INVERSION ON OUR TERRAIN. AS FOR POPS...KEPT THEM IN THE SINGLE DIGITS THROUGH THURSDAY MORNING...SIMILAR TO MOS. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 325 PM EDT TUE SEP 22 2015 THE EXTENDED PORTION OF THE FORECAST BEGINS ON THURSDAY WITH A PERSISTENT BROAD UPPER LEVEL RIDGE IN PLACE OVER THE ENTIRE CONUS. TO BEGIN THE EXTENDED...THE UPPER LEVEL FLOW REMAINS TO THE NORTH ALONG THE CANADIAN BORDER AS WELL. THE AREA IN QUESTION WILL CONTINUE TO BE THE SOUTHEASTERN CONUS WITH A COUPLE TROPICAL LOWS MEANDERING NORTHERLY OUT OF THE GULF OF MEXICO AND SOUTHEAST ATLANTIC COAST BY THE WEEKEND AND INTO THE START OF NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 217 AM EDT WED SEP 23 2015 HIGH PRESSURE OFF TO OUR NORTHEAST WILL PROVIDE FOR MAINLY VFR CONDITIONS THROUGH THE PERIOD. THE ONLY EXCEPTION WILL BE SOME MVFR OR WORSE FOG THROUGH 13Z. IFR OR WORSE FOG LOOKS TO BE MORE RESTRICTED TO THE DEEPER RIVER VALLEYS...AND HAVE ONLY MENTIONED TEMPORARY MVFR CONDITIONS AT MOST OF THE TAF SITES BETWEEN 08 AND 12Z. ONCE THE FOG BURNS OFF...SOME CUMULUS IN THE 3-5K FEET AGL RANGE WILL BE SEEN DURING THE AFTERNOON HOURS. WINDS WILL BE OUT OF THE NORTHEAST AT AROUND 5 KTS OR LESS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEOGERIAN SHORT TERM...GREIF LONG TERM...SHALLENBERGER AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
949 AM EDT WED SEP 23 2015 .SYNOPSIS... HIGH PRESSURE BUILDS TO THE NORTH THROUGH FRIDAY...AS LOW PRESSURE WEAKENS AND RETROGRADES FROM OFF THE CAROLINA COAST INTO THE SOUTHEASTERN UNITED STATES. THE LOW THEN APPROACHES THE MID-ATLANTIC FROM THE SOUTH OVER THE WEEKEND...LIKELY STAYING OFF THE COAST AS IT MOVES NORTHEAST. && .NEAR TERM /THROUGH TONIGHT/... VISIBLE SATELLITE IMAGERY AT 1330Z SHOWS LOW CLOUDS LINGERING IN MANY VALLEYS ALONG AND WEST OF THE BLUE RIDGE. HAVE UPDATED THE SKY COVER GRIDS TO DEPICT THIS...AND LOOKING AT LATEST RAP UPDATES EXPECT IT TO DISSIPATE BY NOON TIME. NE WINDS SHOULD BE GUSTING CLOSE TO 15-20KTS IN MANY LOCATIONS ALONG AND EAST OF I-95 WITH THE PEAK HEATING LATE THIS MORNING AND THROUGH MID AFTERNOON. REMAINDER OF FORECAST IS RIGHT ON TRACK WITH NO CHANGES. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... SIMILAR SYNOPTIC SETUP THURSDAY INTO THUR NIGHT WITH THE HIGH CONTINUING TO STRENGTHEN AND CONTROLLING THE AREA. THIS WILL KEEP DRY CONDITIONS AND PERSIST NE FLOW IN PLACE. TEMPS SIMILAR TO WED BOTH THURS AND THURS NIGHT. 00Z MODEL SUITE BEGINS TO DIFFER ON SOLUTIONS LATE THURS NIGHT AND ON THRU FRI WITH THE NORTHWARD PROGRESSION OF THE PCPN. THINKING IT WILL TAKE TILL LATE THURS NIGHT...AND MORE SO AFTR DAYBREAK...TO SATURATE THE VERTICAL COLUMN ENOUGH TO GENERATE RAIN. INCRSG ELY FLOW SHOULD PROVIDE ENOUGH MOISTURE ADVECTION TO AID IN THIS. MULTIPLE WEAK SHORTWAVES MOVE THRU THE REGION...TRIGGERING SHOWERS BY FRI AFTN AND THRU FRI NIGHT. NOTING THE ELY FLOW RESULTING IN TERRAIN CIRCULATIONS...THINKING THE HIGHER CHC FOR PCPN WILL BE WEST OF THE BLUE RIDGE DURING THIS PERIOD. HAVE CAPPED POPS AT CHC FOR NOW TO ACCOUNT FOR THE UNCERTAINTY OF THE TIMING AND LOCATIONS. A RETURN TO THE ELY FLOW...OVERCAST SKIES...AND LIGHT PCPN MEANS LOWER TEMPS. HIGHS CURRENTLY FORECASTED IN THE 70S...WITH SPOTS TO THE WEST ONLY IN THE 60S. && .LONG TERM /SATURDAY THROUGH TUESDAY/... WHILE MODEL UNCERTAINTY REMAINS MODERATELY HIGH...UNSETTLED WEATHER APPEARS POSSIBLE OVER THE WEEKEND AND MAYBE EVEN INTO EARLY NEXT WEEK...AS MID-ATLANTIC RESIDES IN COOL SECTOR WITH EASTERLY FLOW BETWEEN SFC HP CENTERED OVER NE STATES/CANADA AND SFC LP OVER SE STATES. LATEST MODEL GUIDANCE OFFERS MIXED SIGNAL FOR UPCOMING WEEKEND...WITH 00Z GFS/GEFS/ECMWF OFFERING MANY DIFFERENT SOLUTIONS. GFS FAMILY MORE BULLISH WITH RESPECT TO QPF OVER THE AREA...AS MOST MEMBERS STRENGTHEN SFC LOW SOONER AND TRACK IT CLOSER TO THE COAST...ALLOWING FOR SHOWERS...SOME MODERATE...OVER A LARGER AREA. 00Z ECMWF IS SLOWER TO DEVELOP LOW AND ONCE IT DOES KEEPS MAIN IMPACTS TO OUR EAST...LEAVING US WITH ONLY AN OROGRAPHIC QPF SIGNAL. EVEN WITHOUT PRECIP...IT LOOKS TO BE RATHER CLOUDY OVER MUCH OF THE AREA...AS EASTERLY FLOW ADVECTS LOW-LEVEL MARINE LAYER INTO THE REGION...WHICH WILL KEEP HIGHS IN U60S/L70S EACH DAY. NEARLY ALL GUIDANCE HAS IMPROVING CONDITIONS BY LATE MONDAY INTO TUESDAY...AS HIGH PRESSURE RETURNS AND A WARMING TREND ENSUES. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... GENERALLY VFR CONDITIONS AT THE TAF SITES. VFR CONDITIONS THEN THRU THE REMAINDER OF THE TAF PERIOD. NW FLOW PERSISTS...10-15 KTS. VFR THURS THRU THE FIRST HALF OF THURS NIGHT WITH CONTINUING NE FLOW 5-10 KTS. WINDS BECOME ELY SECOND HALF OF THURS NIGHT...WITH SUB-VFR CIGS RESULTING. TIMING STILL UNCERTAIN OF THE LOWER CIG DEVELOPMENT. EXPECT THE MVFR CIGS THRU FRI MORNING...WITH CONDITIONS POSSIBLY IMPRVG LATE IN THE DAY. ANY IMPROVEMENT WILL BE SHORT LIVED WITH CIGS DROPPING FRI NIGHT BACK TO MVFR OR POSSIBLY IFR. POTENTIAL FOR SUB-VFR SATURDAY AND SUNDAY...WITH EASTERLY WINDS TRANSPORTING MARINE LAYER WESTWARD AND RAIN SHOWERS POSSIBLE. && .MARINE... SCA FOR TODAY FOR MOST OF CHESAPEAKE AND LOWEST TIDAL POTOMAC WITH WINDS INCREASING. THE SCA REMAINS IN EFFECT THRU TONIGHT FOR THE MID CHESAPEAKE BAY AND LOWER TIDAL POTOMAC ZONES...THOUGH COULD SEE AS WE ARE SEEING TONIGHT PERIODS OF SUB- SCA CONDITIONS. THE SCA CONTINUES THURS NIGHT AND MOST LIKELY WILL NEED TO BE EXTENDED INTO FRIDAY. LIGHT RAIN PSBL ON ALL THE WATERS FRIDAY AS WELL. SMALL CRAFT ADVISORY PROBABLE SATURDAY THROUGH LATE IN THE DAY SUNDAY...AS LOW APPROACHES AND EASTERLY FLOW REMAINS STRONG. WINDS REMAIN ELEVATED...BUT SUB-SCA...SUNDAY NIGHT INTO MONDAY...ALTHOUGH TRACK/STRENGTH OF THE LOW COULD LEAD TO WINDS REMAINING NEAR SCA THROUGH MONDAY. && .TIDES/COASTAL FLOODING... A COASTAL FLOOD ADVISORY HAS BEEN ISSUED FOR ST MARYS...CALVERT AND ANNE ARUNDEL...ST MARYS FOR THIS MORNINGS AND TONIGHTS HIGH TIDE...AND THE OTHER TWO FOR TONIGHTS HIGH TIDE CYCLE. ANOMALIES HAVE DIMINISHED EARLY THIS MORNING WITH WEAKENING IN THE NE FLOW. HOWEVER...THIS WILL BE SHORT LIVED...WITH INCRSG NE FLOW TODAY INTO TONIGHT AIDING IN PUSHING ANOMALIES BACK UP TO BETWEEN HALF A FOOT TO A FOOT IN SOME SPOTS. ASTRONOMICAL TIDES ARE ON THE RISE AS WELL. WITH LITTLE CHANGE EXPECTED IN THE WINDS THRU THURS NIGHT...AND COMBINING WITH THE INCRSG ASTRONOMICAL TIDE...MINOR FLOOD LVLS MAY BE REACHED DURING THE HIGH TIDE CYCLE AT SITES ALONG THE WESTERN CHESAPEAKE BAY...MAINLY BALTIMORE AND TO THE SOUTH...AND THE SOUTHERN PORTIONS OF THE TIDAL POTOMAC THRU THE HIGH TIDE CYCLE THURSDAY NIGHT. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 2 AM EDT THURSDAY FOR MDZ018. COASTAL FLOOD ADVISORY FROM MIDNIGHT TONIGHT TO 5 AM EDT THURSDAY FOR MDZ014. COASTAL FLOOD ADVISORY UNTIL 2 AM EDT THURSDAY FOR MDZ017. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ531- 538>542. COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 2 AM EDT THURSDAY FOR ANZ542. SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR ANZ533-534-537- 543. SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ532. && $$ SYNOPSIS...SEARS NEAR TERM...LEE SHORT TERM...SEARS LONG TERM...MSE AVIATION...SEARS/MSE/LEE MARINE...SEARS/MSE/LEE TIDES/COASTAL FLOODING...LWX
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
133 AM EDT WED SEP 23 2015 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 319 PM EDT TUE SEP 22 2015 DRY AND MOSTLY CLEAR WEATHER IS EXPECTED INTO EARLY NEXT WEEK. HIGH TEMPERATURES WILL BE IN THE MID TO UPPER 70S...WHICH IS 5 TO 10 DEGREES ABOVE NORMAL FOR THE END OF SEPTEMBER. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 319 PM EDT TUE SEP 22 2015 MAIN CONCERN IS CLOUDINESS TONIGHT POSSIBLE EXTENDING SOUTH INTO OUR NORTHERN FORECAST AREA. WE EXPECT PRECIPITATION TO REMAIN WELL NORTH OF THE AREA BASED ON A CONSENSUS OF CONVECTION ALLOWING MODELS. CONFIDENCE IS HIGH THAT THE REST OF THE PERIOD WILL REMAIN DRY. AT 1 PM...A FRONT EXTENDED FROM EASTERN LAKE SUPERIOR ACROSS WISCONSIN...NORTHERN IOWA...AND NEBRASKA. THIS BOUNDARY WILL PIVOT CLOCKWISE AND SPREAD ASSOCIATED CLOUDINESS SOUTH INTO NORTHERN LOWER MICHIGAN. THIS CLOUDINESS MAY PERSIST A GOOD PART OF WEDNESDAY OVER NORTHERN LOWER WITH LESS IMPACT OVER SOUTHWEST LOWER. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT WILL BE DOMINATED BY SURFACE HIGH PRESSURE CENTERED TO THE NORTHEAST AND LOCAL WINDS FROM THE EAST...WHICH IS TYPICALLY A DRY PATTERN. THERE IS EXCELLENT CONSENSUS AMONG THE MODELS WITH THIS...SO FORECAST CERTAINTY IS GOOD. .LONG TERM...(FRIDAY THROUGH TUESDAY) ISSUED AT 319 PM EDT TUE SEP 22 2015 HAVE MAINTAINED THE DRY FORECAST THROUGH THE LONG TERM PERIOD OF FRIDAY THROUGH TUESDAY. THE ECMWF AND GFS ARE PRETTY SIMILAR INTO SUNDAY...WHICH IS WHEN DIFFERENCES BEGIN TO SHOW UP. DRY WEATHER WITH 500MB RIDGING LOOKS TO BE A SOLID FORECAST THROUGH SUNDAY. ON SUNDAY...THE GFS MAINTAINS THE RIDGING...WHILE THE ECMWF DRIVES A TROUGH INTO THE NORTHERN PLAINS. ON MONDAY...THE ECMWF SWINGS THE TROUGH INTO THE GREAT LAKES WHERE AS THE GFS CONTINUES THE RIDGING. BIG DIFFERENCES ARE IN PLAY BY TUESDAY...WHERE THE OPERATIONAL ECMWF HAS A TROUGH IN THE GREAT LAKES AND A RIDGE IN THE PLAINS. THE GFS ON TUESDAY IS THE OPPOSITE. BASED ON THE POOR CONTINUITY DECIDED TO CONTINUE THE DRY FORECAST EARLY NEXT WEEK AND WAIT FOR MORE OF A CONSENSUS BEFORE FLIPPING THE FORECAST COOLER AND WETTER FOR MONDAY INTO TUESDAY. DRY AND FAIR WEATHER WILL BE THE THEME OF THE LONG TERM...WITH HIGH CONFIDENCE THROUGH SUNDAY. HIGHS ARE FORECAST TO BE IN THE 70S EACH DAY. AGAIN...CONFIDENCE SLIDES A BIT EARLY NEXT WEEK GIVEN THE MODEL VARIABILITY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 130 AM EDT WED SEP 23 2015 IT/S POSSIBLE THAT WE COULD SEE PATCHY MVFR FOG BETWEEN 09-13Z BUT CONFIDENCE WAS LOW ENOUGH TO KEEP OUT OF THE TAFS...BUT SOMETHING TO KEEP AN EYE ON. OTHERWISE SOME HIGH CLOUDS ARE EXPECTED THROUGH THE PERIOD. && .MARINE... ISSUED AT 319 PM EDT TUE SEP 22 2015 LUDINGTON BUOY HAS BEEN SLIGHTLY OVER-PERFORMING AROUND 3 FEET THE LAST SEVERAL HOURS. BIG SABLE POINT AND LUDINGTON SITES HAVE BEEN REPORTING GUSTS OF 15 TO 20 KT FROM THE SOUTH WHICH MAY BE AIDING THE WAVE GROWTH. ADDITIONALLY...RECENT HRRR RUNS SUGGEST A CORRIDOR OF STRONGER SOUTHERLY WINDS HAVE BEEN OCCURRING JUST OFFSHORE. EXPECT WINDS TO RELAX THIS EVENING AND SHIFT TO THE SOUTHEAST WITH A LAND BREEZE...WHICH SHOULD ALLOW WAVES TO DIMINISH. AFTER THIS...THERE ARE NO CONCERNS. && .HYDROLOGY... ISSUED AT 319 PM EDT TUE SEP 22 2015 NO PRECIPITATION IS FORECAST THROUGH THROUGH THIS WEEK. RIVER LEVELS ARE EXPECTED TO HOLD STEADY OR FALL SLOWLY THROUGH THE WEEK. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...TJT SHORT TERM...TJT LONG TERM...DUKE AVIATION...04 HYDROLOGY...TJT MARINE...TJT
AREA FORECAST DISCUSSION
NWS DULUTH MN
359 PM CDT WED SEP 23 2015 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 357 PM CDT WED SEP 23 2015 RAIN CONTINUES INTO THE NIGHT WITH DREARY CONDITIONS PERSISTING INTO TOMORROW. TEMPERATURES HAVE BEEN COOL TODAY ESPECIALLY ALONG THE LAKE SUPERIOR COASTLINE WHERE WINDS HAVE BEEN STRONG OFF THE LAKE...GUSTING TO 25 TO 35 MPH AT TIMES. WARMER TOMORROW...BUT SKIES REMAIN MOSTLY CLOUDY. FORECAST WORKED OUT FAIRLY WELL TODAY WITH THE AXIS OF HEAVIEST PRECIP ABOUT WHERE WE WERE EXPECTING IT. THE FIRST ROUND OF STORMS TAPERED OFF FASTER THAN ANTICIPATED THIS AFTERNOON...BUT ADDITIONAL DEVELOPMENT IS ALREADY ONGOING AND ANOTHER WAVE OF WIDESPREAD RAINFALL IS EXPECTED LATE TONIGHT. WHILE FLASH FLOOD THREAT IS FAIRLY LOW DUE TO STORM MOTION...SOME URBAN AND SMALL STREAM FLOODING IS POSSIBLE WITH ANY STORM TONIGHT DUE TO THE EXTREMELY MOIST NATURE OF THE ATMOSPHERE. PRECIPITABLE WATER VALUES OF 1.0 TO 1.4 ALREADY EXIST ACROSS THE AREA PER RAP/MESOANALYSIS AND EVEN HIGHER PWATS ARE ABOUT TO BE ADVECTED INTO NORTHWEST WISCONSIN THIS EVENING AS THE UPPER LOW/SHORTWAVE OVER THE MID MISSOURI VALLEY GRADUALLY DRIFTS EASTWARD. CURRENT RAP INDICATES PWATS WILL RISE TO 1.4 TO 1.6 INCHES OR HIGHER FROM THE TWIN PORTS AND INTERSTATE 35 CORRIDOR EAST ACROSS PARTS OF NORTHWEST WISCONSIN. THE SOUTH SHORE OF WISCONSIN IS ESPECIALLY PRIMED FOR POTENTIAL FLOODING AFTER HEAVY RAINFALL THIS AFTERNOON BROUGHT AROUND TWO INCHES TO MUCH OF NORTHERN DOUGLAS AND BAYFIELD COUNTIES. WHILE MOST OF THIS RAINFALL SIMPLY RUNS OFF INTO LAKE SUPERIOR...SATURATED GROUNDS COULD LEAD TO MINOR FLOODING TONIGHT. WINDS WILL GRADUALLY WEAKEN TONIGHT...BUT REMAIN GUSTY AT TIMES ALONG THE LAKE SUPERIOR SHORELINE. SOME PATCHY FOG POSSIBLY ESPECIALLY IN THE BRAINERD LAKES TO LEECH LAKE AREA WHERE LIGHTER WINDS ARE EXPECTED. FOR THURSDAY THINGS WILL WIND DOWN AS THE UPPER LOW/SHORTWAVE DISSIPATES AND A RIDGE BUILDS OVER THE FOUR CORNERS REGION INTO THE CENTRAL/NORTHERN PLAINS. THE WEAK WARM FRONT CURRENTLY ACROSS NORTHWEST WISCONSIN WILL GRADUALLY DRIFT SOUTHWARD AND DISSIPATE...THOUGH LOW LEVEL MOISTURE IS EXPECTED TO REMAIN IN PLACE THROUGH THE DAY RESULTING IN MOSTLY CLOUDY SKIES. A WEAK SHORTWAVE TROUGH WILL MOVE ACROSS SOUTHERN MANITOBA INTO NORTHWEST ONTARIO WHICH COULD RESULT IN A FEW SHOWERS IN NORTHEAST MINNESOTA...AND WITH THE MOISTURE ALREADY IN PLACE IT MAY NOT TAKE MUCH LIFT TO GET RAIN/DRIZZLE GOING. TEMPS A LITTLE WARMER DUE TO WARM AIR ADVECTION TAKING PLACE THROUGH THE DAY...HIGHS IN THE UPPER 50S TO LOW 60S ACROSS THE MN ARROWHEAD TO MID 60S TO NEAR 70 ELSEWHERE. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 357 PM CDT WED SEP 23 2015 WEAK UPPER RIDGING BUILDING IN THURSDAY NIGHT INTO FRIDAY WILL BRING MAINLY DRY CONDITIONS FOR MOST AREAS OF THE NORTHLAND. THERE MAY BE SOME SHOWERS THAT LINGER OVER FAR NORTHERN MINNESOTA INTO FRIDAY MORNING. CLOUDS WILL BE SLOW TO DISSIPATE FRIDAY AND WE INCREASED THEM AND THEY MAY HAVE TO BE INCREASED FURTHER AS SOME OF THE MODELS ARE SHOWING LOW LEVEL MOISTURE SLOW TO DEPART. HIGHS SHOULD BE FROM THE UPPER SIXTIES TO LOWER SEVENTIES. THE NORTHLAND WILL BE BETWEEN DEPARTING HIGH PRESSURE TO THE EAST AND A COLD FRONT WELL WEST ON SATURDAY. THIS WILL CREATE A WARM SOUTHERLY FLOW WITH HIGHS IN THE MID TO UPPER SEVENTIES. THE UPPER FLOW WILL BECOME INCREASINGLY MORE WESTERLY THROUGH THE WEEKEND INTO EARLY NEXT WEEK PUSHING THE COLD FRONT THROUGH THE REGION AND SENDING SEVERAL SHORTWAVES THROUGH AS WELL. WE HAVE CHANCES FOR SHOWERS/STORMS SUNDAY INTO TUESDAY. TEMPERATURES SUNDAY WILL STILL BE IN THE SEVENTIES THEN FALL INTO THE SIXTIES TUESDAY AND WEDNESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY) ISSUED AT 105 PM CDT WED SEP 23 2015 IFR CIGS HAVE SPREAD IN TO MOST OF THE AREA...AND RAP CPD/S INDICATE EXPANDING LOW LEVEL MOISTURE AS DO THE MODEL SOUNDINGS OFF THE NAM AND RAP...WITH THE LOWEST CEILINGS POSSIBLE EARLY TOMORROW MORNING. MUCH OF THE WESTERN AND NORTHERN PORTION OF THE FA LOOK TO SEE MORE SCATTERED SHOWER DEVELOPMENT THROUGH THE PERIOD...BUT CLOQUET...DULUTH...HIBBING LOOK TO SEE MORE WIDESPREAD RAINFALL TONIGHT. THUNDER REMAINS POSSIBLE THIS AFTERNOON...BUT AS WE PROGRESS THROUGH THE NIGHT...THE CHANCE FOR THUNDER QUICKLY DIMINISHES. REMAINED CONSISTENT WITH LATEST GUIDANCE AND PREVIOUS TAFS THAT IFR CIGS/VIS WILL IMPACT THE AREA THROUGH TOMORROW MORNING. && .PRELIMINARY POINT TEMPS/POPS... DLH 51 62 53 69 / 70 70 10 10 INL 48 63 51 71 / 40 30 20 20 BRD 55 68 54 74 / 50 50 10 10 HYR 55 70 51 74 / 60 70 10 10 ASX 53 67 51 70 / 70 60 10 10 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...BEACH HAZARDS STATEMENT UNTIL 9 PM CDT THIS EVENING FOR WIZ001. MN...BEACH HAZARDS STATEMENT UNTIL 9 PM CDT THIS EVENING FOR MNZ037. LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THURSDAY FOR LSZ121-140>148. && $$ SHORT TERM...JJM LONG TERM...MELDE AVIATION...SPD
AREA FORECAST DISCUSSION
NWS DULUTH MN
110 PM CDT WED SEP 23 2015 .SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON) ISSUED AT 334 AM CDT WED SEP 23 2015 MAIN CONCERNS IN THE SHORT TERM ARE FOCUSED AROUND THE INCOMING SHOWERS AND STORMS TODAY AND THURSDAY WITH PERSISTENT RAIN LEADING TO THE POTENTIAL FOR LOCALIZED FLOODING IN SOME AREAS. ALSO FOCUSED ON THE GUSTY E/NE WINDS OFF LAKE SUPERIOR TODAY AND TONIGHT KEEPING CONDITIONS MUCH COOLER AND MORE AUTUMN-LIKE AROUND THE TWIN PORTS. THE RAIN IS EXPECTED TO DEVELOP AND SPREAD SW TO NE ACROSS THE NORTHLAND TODAY WITH THUNDERSTORMS EMBEDDED WITHIN THE PRECIP SHEILD. THE LARGE-SCALE FORCING WITH THIS SYSTEM WILL BE FAIRLY WEAK AS THE JET STREAM REMAINS NORTH OF THE INTERNATIONAL BORDER. THE COMBINATION OF SLOW STORM MOTION AND A LARGE PUSH OF DEEP LAYER MOISTURE FROM THE GULF OF MEXICO...PWATS AROUND 1.5 INCHES...ACROSS THE UPPER MIDWEST WILL ALLOW FOR A LONG- DURATION HEAVY RAINFALL EVENT TODAY AND TOMORROW. SCATTERED THUNDERSTORMS WITHIN THE SYSTEM WILL ALSO CONTRIBUTE TO THE THREAT FOR LOCALIZED FLOODING. HOWEVER...SINCE CONVECTIVE PARAMETERS WILL BE WEAK TO VERY MARGINAL AND THE RAINFALL IS EXPECTED OVER A RELATIVELY LONG PERIOD OF TIME AND SURFACE/GROUND CONDITIONS ARE STILL ON THE DRIER END OF THE SPECTRUM AND CAPABLE OF ABSORBING MOST OF THE RAIN EFFICIENTLY ENOUGH TO KEEP UP WITH THE PRECIP...NOT EXPECTING WIDESPREAD FLOODING CONCERNS. THE REGULAR NASCENCE FLOODING CAN BE EXPECTED IN THE USUAL LOCATIONS. THE BULK OF THIS RAIN WILL FORM ALONG A NEWD EXTENSION OF AN INVERTED TROUGH FROM THE SRN PLAINS THROUGH SD/NEB/MINNESOTA. AS THIS SYSTEM APPROACHES...HIGH PRESSURE WILL BUILD OVER S/ERN ONTARIO AND ACT TO CREATE A LOCALIZED PRESSURE GRADIENT ACROSS WRN LAKE SUPERIOR. THIS GRADIENT WILL ALLOW FOR A STRONG E/NE WIND TO DEVELOP THIS MORNING AND INTO THE AFTERNOON...AND LAST THROUGH TONIGHT. THIS WIND WILL KEEP CONDITIONS MUCH COOLER AROUND THE TWIN PORTS AND THE NORTH SHORE TODAY. HIGHS WILL ONLY TOP OUT IN THE 50S...WITH 60S FURTHER INLAND. TEMPERATURES WILL REMAIN NEARLY STATIONARY TONIGHT AS CLOUD COVER PERSISTS WITH THE WIDESPREAD RAIN AND SCATTERED STORMS POSSIBLE. THE SYSTEM BEGINS TO FALL APART THROUGH THE DAY TOMORROW AS THE UPPER TROUGH ARRIVES AND STARTS TO KICK THE ENTIRE SYSTEM EWD. MORNING RAIN WILL BREAK UP INTO SCATTERED SHOWERS IN THE AFTERNOON ON THURSDAY WITH TEMPERATURES REBOUNDING BACK INTO THE 60S AND LOWER 70S. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 334 AM CDT WED SEP 23 2015 THE SHORTWAVE THAT WILL HAVE BROUGHT ALL THE RAIN TO THE NORTHLAND THROUGH THURSDAY WILL GRADUALLY MOVE OUT OF THE REGION THURSDAY NIGHT AND FRIDAY. STRONG UPPER LEVEL RIDGING WILL PREVAIL ACROSS THE AREA THROUGH THE END OF THE WEEK AND INTO SATURDAY...WITH A PATTERN MORE REMINISCENT OF SUMMER. HEIGHTS WILL LATER SUNDAY AND MONDAY...AS AN UPPER LEVEL SHORTWAVE AND A COLD FRONT DROP ACROSS THE NORTHLAND. THERE IS SOME DIFFERENCE IN THE MAGNITUDE OF THE TROUGH AND THE COLD FRONT...WITH THE ECMWF INDICATING A STRONGER COLD FRONTAL PASSAGE LATER SUNDAY AND SUNDAY NIGHT. THE GFS INDICATES A LESS AMPLIFIED UPPER LEVEL TROUGH DURING THAT TIME FRAME...BUT CATCHES UP BY MONDAY AND TUESDAY TO SOME EXTENT. OVERALL THE TREND WILL BE FOR AN UNSEASONABLY WARM AND DRY WEEKEND...FOLLOWED BY SOMEWHAT OF A COOL DOWN EARLY NEXT WEEK. LOOKING AHEAD BEYOND THAT...THE GFS AND ECMWF BOTH INDICATE A MASSIVE RIDGE DEVELOPING IN THE WEST AND CENTRAL DURING THE LATTER PART OF THE WORK WEEK. HIGHS FROM FRIDAY INTO MONDAY ARE EXPECTED TO BE IN THE 70S FOR THE MOST PART. TEMPERATURES WILL THEN COOL INTO THE 60S FOR DAYTIME HIGHS ON TUESDAY AND WEDNESDAY OF NEXT WEEK. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE 40S AND 50S. FRIDAY AND SATURDAY SHOULD BE DRY AND WARM...WITH SHOWERS AND THUNDERSTORMS POSSIBLE SUNDAY INTO THE FIRST PART OF THE WORK WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY) ISSUED AT 105 PM CDT WED SEP 23 2015 IFR CIGS HAVE SPREAD IN TO MOST OF THE AREA...AND RAP CPD/S INDICATE EXPANDING LOW LEVEL MOISTURE AS DO THE MODEL SOUNDINGS OFF THE NAM AND RAP...WITH THE LOWEST CEILINGS POSSIBLE EARLY TOMORROW MORNING. MUCH OF THE WESTERN AND NORTHERN PORTION OF THE FA LOOK TO SEE MORE SCATTERED SHOWER DEVELOPMENT THROUGH THE PERIOD...BUT CLOQUET...DULUTH...HIBBING LOOK TO SEE MORE WIDESPREAD RAINFALL TONIGHT. THUNDER REMAINS POSSIBLE THIS AFTERNOON...BUT AS WE PROGRESS THROUGH THE NIGHT...THE CHANCE FOR THUNDER QUICKLY DIMINISHES. REMAINED CONSISTENT WITH LATEST GUIDANCE AND PREVIOUS TAFS THAT IFR CIGS/VIS WILL IMPACT THE AREA THROUGH TOMORROW MORNING. && .PRELIMINARY POINT TEMPS/POPS... DLH 55 52 64 53 / 80 80 70 10 INL 59 49 63 51 / 30 60 40 20 BRD 61 55 71 54 / 80 70 50 10 HYR 66 57 70 52 / 60 70 50 10 ASX 61 56 68 51 / 70 70 50 10 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THURSDAY FOR LSZ121-140>148. && $$ SHORT TERM...TENTINGER LONG TERM...DAP AVIATION...SPD
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1133 PM CDT TUE SEP 22 2015 .UPDATE: Issued at 936 PM CDT Tue Sep 22 2015 Area of showers and thunderstorms currently over western Iowa and northwest Missouri will stay west of the area tonight as latest runs of the RAP and HRRR are showing forcing and instability will remain nearly stationary overnight. Otherwise going forecast looks good and have made only minor changes for debris cloudiness coming off the convection to our west. Overnight lows still look reasonable. Britt && .SHORT TERM: (Through Late Tonight) Issued at 213 PM CDT Tue Sep 22 2015 Look for quiet weather tonight with occasional clouds and overnight lows in the mid 50s to around 60. Kanofsky .LONG TERM: (Wednesday through Next Tuesday) Issued at 213 PM CDT Tue Sep 22 2015 Quiet fall weather conditions are expected through at least the end of the week and possibly through the weekend. Expect temperatures to be around 5-8 degrees above average during each forecast period with highs in the low to mid 80s and lows in the upper 50s to lower 60s. There are no strong signals for widespread rainfall over the next 5 days. A series of vort maxes was noted across the southwestern CONUS on early afternoon water vapor imagery. These features will lift into the central plains tonight and tomorrow, then linger in place or perhaps even retrograde through the end of the week due to weak steering flow aloft near the axis of a building upper ridge. These features are currently forecast to remain west of the CWA with little effect other than increased mid/high cloudiness at times, although iso-sct SH/TS would be possible if these features progress farther east than currently expected. Forecast uncertainty increases by late this weekend into early next week. There is poor run-to-run continuity between recent GFS runs regarding a low pressure system moving through either Canada (06z run) or the northwestern quadrant of the CONUS (12z run) which then acts to break down the upper ridge. There is also poor agreement between the GFS and ECMWF due to differences in each model`s handling of a developing ridge over the western CONUS and how that ridge affects the approaching low pressure system. This low pressure system and its associated cold front could bring a chance of rain showers to the area during the early or middle part of next week, but confidence is too low to raise PoPs attm due to the aforementioned model disagreements. Kanofsky && .AVIATION: (For the 06z TAFs through 06z Wednesday Night) Issued at 1129 PM CDT Tue Sep 22 2015 Surface ridge extends from MI southwest into eastern MO. E-sely surface winds will continue through the period, light late tonight then only increasing to around 7 kts late Wednesday morning and afternoon. Mainly just some high level cloudiness through the forecast period. There may be a brief period of light fog in SUS and possibly also CPS late tonight/early Wednesday morning. Specifics for KSTL: Just some high level cloudiness through the forecast period. Light e-sely surface wind late tonight will increase to around 7 kts Wednesday afternoon, then become light again Wednesday night. GKS && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
842 PM MDT THU SEP 24 2015 .UPDATE... ANOTHER QUIET NIGHT IN STORE ACROSS THE FORECAST AREA. HIGH PRESSURE RIDGING WILL CONTINUE WITH ITS AXIS SLOWLY SHIFTING EAST OVER EASTERN MONTANA TONIGHT. CURRENT FORECAST REMAINS IN GOOD SHAPE BUT I DID MAKE A COUPLE OF ADJUSTMENTS. SATELLITE IS CURRENTLY SHOWING QUITE A BIT OF MID AND HIGH LEVEL CLOUDS MOVING ACROSS THE SOUTHWEST PORTIONS OF THE STATE AND INTO OUR WESTERN AND CENTRAL LOCATIONS. THESE CLOUDS WILL CONTINUE TO STREAM ACROSS THE FORECAST AREA TONIGHT RESULTING IN PARTLY CLOUDY SKIES. AS A RESULT...I ADJUSTED A MOSTLY CLEAR FORECAST TO PARTLY CLOUDY. THE OTHER UPDATE TO THE FORECAST WAS TO ADD PATCHY FOG ONCE AGAIN TO THE EASTERN HALF OF FALLON AND CARTER COUNTIES AFTER MIDNIGHT INTO MID MORNING FRIDAY. TEMP/DEW POINT SPREADS ARE NOT AS SMALL AS LAST NIGHT BUT STILL FAIRLY CLOSE PLUS THE HRRR ONCE AGAIN IS SHOWING SOME FOG OR LOW STRATUS NEAR THE DAKOTA BORDERS. UPDATED FORECAST HAS BEEN SENT. HOOLEY && .SHORT TERM...VALID FOR FRI AND SAT... SUMMER LIKE RIDGE OVER THE AREA BEGINNING TO BREAK DOWN BUT A COUPLE OF HOT DAYS AHEAD AS MIXING INCREASES ACROSS THE REGION. CLEAR CONDITIONS OVERNIGHT WITH LOW LEVEL JET DEVELOPMENT OVER SOUTHEAST MONTANA WHICH IS EXPECTED TO KEEP FOG FROM REDEVELOPING OVER CUSTER AND FALLON COUNTIES. FRIDAY WEAK DISTURBANCE WORKING INTO WESTERN MONTANA WILL CAUSE THE RIDGE AXIS TO SHIFT EASTWARD ACROSS THE STATE WHICH BRINGS A DECREASE IN STABILITY AND PROMOTES DEEPER MIXING. DEVELOPING LOW PRESSURE OVER NORTH CENTRAL MONTANA AND INCREASING MID LEVEL FLOW WILL SUPPORT DOWNSLOPE ACROSS THE AREA AND SHOULD SEE RECORD HIGH TEMPERATURES AND POSSIBLY RECORD WARMTH FOR SO LATE IN THE SEASON. FIRE CONCERNS FOR THE WESTERN ZONES AREA ELEVATED DUE TO THE GUSTY WINDS MIXING IN THE AFTERNOON COMBINING WITH HUMIDITY IN THE TEENS. MAINTAINED THE THREAT FOR AN ISOLATED THUNDERSTORM BUT NOT AS CONFIDENT THE SET UP SUPPORTS IT BUT WILL GIVE LATE SHIFTS A CHANCE TO EVALUATE 700MB THETA E PROGS TO SEE WHERE CONVECTION THIS AFTERNOON DEVELOPS AND WHERE IT WOULD PROJECT TO TOMORROW. MILD NIGHT FRIDAY NIGHT WITH HEIGHTS FALLING SATURDAY BUT A WARMER START AND AN APPROACHING COLD FRONT SHOULD ALLOW TEMPERATURES TO APPROACH 90 AGAIN. LIMITING FACTOR IS LOCATION OF THE FRONT WHICH COMES IN PIECES AND THE FIRST PIECE TRIES TO SWITCH TO AN EASTERLY SURFACE WIND FOR THE CENTRAL ZONES BY EARLY AFTERNOON. STILL COULD SEE AN EARLY MAX TEMPERATURE AIDED BY COMPRESSIONAL WARMING AND A FEW MEMBERS OF THE SREF GUIDANCE ACTUALLY HAVE A MAX TEMPERATURE WARMER THAN SATURDAY. OTHER ITEM ON SATURDAY IS ANOTHER CHANCE FOR ISOLATED THUNDERSTORMS BUT AT THIS POINT STILL LOOKS LIKE STORMS WILL BE OVER THE HIGHER TERRAIN. FRONTAL PASSAGE IS FAIRLY GENTLE SATURDAY NIGHT SO DO NOT SEE A BUNCH OF POST FRONTAL WINDS AND IT LOOKS TO BE A DRY PASSAGE AT THIS TIME. BORSUM .LONG TERM...VALID FOR SUN...MON...TUE...WED...THU... MODEL AGREEMENT THROUGH THE EXTENDED HAS IMPROVED WITH THE 12Z RUNS. EXTENDED LOOKS MOSTLY DRY...ASIDE FOR MONDAY EVENING INTO TUESDAY MORNING...AND WITH ABOVE AVERAGE TEMPERATURES IN THE MID TO UPPER 70S ON THE WARMER DAYS AND NEAR 70 ON MONDAY AND TUESDAY. LONG TERM BEGINS WITH A SMALL DISTURBANCE MOVING EAST NEAR AND JUST NORTH OF THE FORECAST AREA. AS THIS DISTURBANCE WILL BE ON A WEAKENING TREND DO NOT MUCH IN TERMS OF PRECIPITATION AND TEMPERATURES WILL STILL BE FAIRLY WARM ON SUNDAY AFTERNOON. IT SHOULD...HOWEVER...HELP DRAG A WEAK COOL FRONT THROUGH THE FORECAST AREA SUNDAY NIGHT. THERE IS WEAK AGREEMENT IN RAIN CHANCES...SO LEFT SLIGHT CHANCE POPS FOR SUNDAY AFTERNOON. UNFORTUNATELY IT APPEARS SOME UPPER LEVEL CLOUDS ASSOCIATED WITH THIS DISTURBANCE COULD PREVENT GOOD VIEWING CONDITIONS FOR SUNDAYS LUNAR ECLIPSE...THOUGH WILL HAVE TO SEE HOW CONDITIONS DEVELOP CLOSER TO THE EVENT. AFTER THE COOL FRONT PUSHES THROUGH...ANOTHER RIDGE AXIS WILL DEVELOP TO OUR WEST ON MONDAY AFTERNOON. SOME MOISTURE AND VERY WEAK ENERGY WILL ROTATE THROUGH THIS RIDGE AXIS LATE MONDAY INTO TUESDAY WHICH SHOULD KEEP CONDITIONS NEAR SEASONABLE LEVELS ON MONDAY AND TUESDAY AFTERNOONS. SIMILAR TO SUNDAYS COOL FRONT... MODELS ARE NOT IN GOOD AGREEMENT WITH PRECIPITATION AMOUNTS SO FOR NOW JUST MENTIONED 20 TO 30 PERCENT CHANCES FOR RAIN THROUGH THESE DAYS LASTLY...WEDNESDAY AND THURSDAY APPEAR TO BRING A RETURN OF ABOVE NORMAL TEMPERATURES TO THE AREA. HOWEVER...UNCERTAINTY IS GREATEST IN THESE TWO DAYS AS THE GLOBAL GUIDANCE HANDLE AN UPPER LEVEL DISTURBANCE DIFFERENTLY. FOR THIS UPDATE WENT WITH OUR NORMAL MODEL BLENDS UNTIL MORE MODEL AGREEMENT SHOWS UP IN THE EXTENDED. DOBBS && .AVIATION... VFR CONDITIONS EXPECT OVER THE NEXT 24 HOURS. SOME LOW CIGS OR FOG ARE POSSIBLE IN EASTERN CARTER AND FALLON COUNTIES TONIGHT... ALONG WITH LOW- LEVEL WIND SHEAR AROUND MILES CITY. WINDS AROUND LIVINGSTON WILL INCREASE DURING THE AFTERNOON TOMORROW. REIMER && .PRELIMINARY POINT TEMP/POPS... FRI SAT SUN MON TUE WED THU ----------------------------------------------------------- BIL 055/091 059/088 055/078 053/072 049/071 050/076 053/074 00/U 00/B 12/W 22/W 22/W 22/W 22/W LVM 050/090 053/087 048/079 048/073 046/068 046/073 046/071 01/N 10/B 02/W 22/W 22/W 22/W 22/W HDN 051/093 053/090 052/081 051/074 048/073 047/078 049/075 00/U 00/B 11/B 22/W 22/W 22/W 22/W MLS 057/092 057/090 055/079 053/072 048/070 049/077 051/075 00/U 00/B 11/B 33/W 22/W 22/W 22/W 4BQ 055/090 056/092 055/081 053/075 049/073 049/078 052/077 00/U 00/B 01/B 32/W 22/W 22/W 21/B BHK 054/085 054/089 054/077 051/070 046/067 048/074 050/075 00/N 00/B 11/B 33/W 22/W 22/W 11/B SHR 050/091 052/091 053/081 051/076 047/073 047/079 048/077 00/U 00/B 01/B 22/W 22/W 22/W 22/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...FIRE WEATHER WATCH IN EFFECT FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING FOR ZONES 28-40-41-63>68. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
856 PM CDT THU SEP 24 2015 .UPDATE... ISSUED AT 855 PM CDT THU SEP 24 2015 UPDATED PRODUCTS A FEW TIMES TO INCREASE RAIN AMOUNTS. THINK THERE COULD BE SOME POCKETS OF UP TO TWO INCHES OF RAIN OVERNIGHT... MAINLY IN WESTERN IOWA. RECENT RAP MODEL OUTPUT SUGGESTS THAT POTENTIAL. CLOSED MID TROPOSPHERIC LOW SHOULD DROP SLOWLY SOUTHWARD THROUGH EASTERN NEBRASKA OVERNIGHT. THIS MAY FOCUS HEAVIEST AND LONGEST DURATION RAIN OVER WESTERN IOWA AND EXTREME EASTERN NEBRASKA NEAR THE MISSOURI RIVER. 00Z COAX SOUNDING WAS QUITE MOIST...WITH 1.74 PRECIPITABLE WATER AND DEEP WARM CLOUD DEPTH. SHOWERS AND SOME ISOLD THUNDERSTORMS HAVE BEEN EFFICIENT RAIN PRODUCERS SO FAR AND THIS MAY CONTINUE OVERNIGHT. ALREADY ISSUED ONE FLOOD ADVISORY PRODUCT. && .SHORT TERM...(TONIGHT THROUGH SUNDAY) ISSUED AT 318 PM CDT THU YEP 24 2015 VERTICALLY STACKED LOW CONTINUES TO SPIN ACROSS NORTHEAST NEBRASKA AT MID AFTERNOON...WITH NUMEROUS SHOWERS NOTED ACROSS THE NORTHERN HALF OF THE FORECAST AREA. INSTABILITY HAS REMAINED ON THE LOW SIDE TODAY...ALTHOUGH SAC HAS INDICATED ABOUT 500 J/KG OF ACROSS SOUTHEAST NEBRASKA. THE LOW WILL RESULT IN NUMEROUS SHOWERS THROUGH THE EVENING HOURS...AND COULD NOT RULE OUT AN ISOLATED RUMBLE OF THUNDER ACROSS SOUTHEAST NEBRASKA. THE LOW GRADUALLY BEGINS TO FILL OVERNIGHT AND DRIFT SOUTH...WITH SPOTTY SHOWERS LINGERING YET THROUGH FRIDAY AS THE LOW FINALLY BEGINS TO OPEN AND SHIFT SOUTHWEST OF THE REGION BY FRIDAY AFTERNOON/NIGHT. ONCE THE RAIN FINALLY ENDS...SHOULD SEE CLEARING SKIES FRIDAY NIGHT...WHICH COULD RESULT IN AREAS OF FOG EARLY SATURDAY MORNING. SOUTHEASTERLY SURFACE FLOW AS THE UPPER RIDGE BUILDS ALOFT WILL PREVAIL THROUGH THE REMAINDER OF THE WEEKEND WITH WARMING TEMPS BACK ABOVE NORMAL AND MOSTLY SUNNY SKIES. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 318 PM CDT THU YEP 24 2015 UPPER RIDGE REMAINS IN PLACE EARLY IN THE PERIOD WHICH SHOULD RESULT IN ANOTHER WARM AND MILD DAY MONDAY. THE NEXT WAVE MOVING ALONG THE US/CANADIAN BORDER SHOULD HELP PUSH A COOL FRONT INTO THE AREA MONDAY NIGHT INTO TUESDAY...WHICH BRINGS A SMALL CHANCE OF THUNDERSTORMS FOR THE NORTHERN HALF OF THE FORECAST AREA. BEYOND THEN...CONFIDENCE IS LOW IN THE DETAILS AS MODELS DIVERGE ON THE SOLUTIONS. ECMWF REMAINS DRY...BUT GFS INDICATES ANOTHER WEAK WAVE MOVING ONTO THE PLAINS WEDNESDAY NIGHT THROUGH THURSDAY. && .AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 615 PM CDT THU SEP 24 2015 THERE COULD BE SOME ISOLD TSRA AROUND THIS EVENING BUT CHANCES SEEM LOW ENOUGH TO JUST MENTION SHRA. CONDITIONS ARE QUITE VARIABLE IN REGARDS TO CIGS...IFR AT KOFK BUT VFR AT KOMA AND KLNK FOR NOW. EXPECT CONDITIONS TO DETERIORATE AT KLNK AND KOMA THIS EVENING WITH MVFR OR IFR CONDITIONS OVERNIGHT. SOME FOG POSSIBLE TOO. IT APPEARS CLOUDS WILL BREAK UP WITH MAINLY VFR CONDITIONS BY MID TO LATE MORNING FRIDAY. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ UPDATE...MILLER SHORT TERM...DEWALD LONG TERM...DEWALD AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
647 PM CDT THU SEP 24 2015 .SYNOPSIS... ISSUED AT 329 PM CDT THU SEP 24 2015 H5 ANALYSIS THIS MORNING HAD A POSITIVE TILTED RIDGE EXTENDING FROM SOUTHERN CALIFORNIA INTO THE NORTHERN ROCKIES. DOWNSTREAM OF THE RIDGE...A CLOSED LOW WAS NOTED OVER NERN NEBRASKA THIS MORNING...WITH A SECONDARY LOW OVER THE TEXAS PANHANDLE. BASED ON CURRENT SATELLITE IMAGERY...THE NORTHERN MOST UPPER LEVEL LOW WAS JUST WEST OF NORFOLK NEBRASKA. LIGHT RAIN SHOWERS IN ASSOCIATION WITH THE LOW...HAVE TRACKED FROM NORTH TO SOUTH ALONG HIGHWAY 281 FROM SPENCER TO BARTLETT THIS MORNING...AND HAVE SINCE DISSIPATED IN COVERAGE THIS AFTN. FURTHER WEST OF THE LOW....A BROAD SHIELD OF CLOUDINESS EXTENDED WEST TO THE NEBRASKA PANHANDLE WITH A MIXTURE OF LOW TO MID CLOUDS PRESENT. OVER THE PAST 1 TO 2 HRS...THE WESTERN EDGE OF THIS CLOUD COVER HAS BEGUN TO BURN OFF WITH CLEARING NOTED OVER PORTIONS OF THE EASTERN NEBRASKA PANHANDLE AND SWRN NEBRASKA. AT THE SURFACE...LOW PRESSURE WAS NOTED OVER NORFOLK NEBRASKA WITH A SURFACE TROUGH EXTENDING SSW INTO CENTRAL AND SWRN KS. WEST OF THE TROUGH NORTHWESTERLY WINDS WERE PRESENT FROM WEST OF THE LOW TO THE PANHANDLE. ACROSS THE PANHANDLE...WINDS WERE LIGHTER FROM THE NORTH OR WEST. TEMPERATURES AS OF 3 PM CDT...RANGED FROM 65 AT AINSWORTH TO 77 AT IMPERIAL. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 329 PM CDT THU SEP 24 2015 MAIN FORECAST CONCERNS OVER THE SHORT TERM...THROUGH FRIDAY AFTERNOON...ARE PRECIPITATION AND FOG. STRONG LOW PRESSURE CENTER CONTINUES TO SIT OVER CENTRAL AND EASTERN NEBRASKA...AND MAY RETROGRADE A LITTLE ON FRIDAY. FOR THE REMAINDER OF THURSDAY AFTERNOON AND EVENING...KEPT ISO/SCT POPS ACROSS NORTH CENTRAL NEBRASKA AS BANDS OF WEAK RAIN ROTATE SOUTH/SOUTHEAST ALONG THE BACKSIDE OF THE SURFACE LOW. LOWERED QPF AS MOST OF THE PRECIPITATION WAS BEING RECORDED AS DRIZZLE BY 20Z. THE TRICKY PART IS HOW FAR WEST THE THICK STRATUS WILL STRETCH THIS EVENING. THE PANHANDLE HAS STAYED CLEAR FOR MOST OF THE DAY AND BREAKS IN THE COVER HAVE COME AND GONE ALONG THE HIGHWAY 83 CORRIDOR. OVERNIGHT INTO FRIDAY MORNING...THINKING THE STRATUS WILL BEGIN TO EXPAND WESTWARD BY 25/06Z AS THE SURFACE LOW TREKS SOUTHWEST. NAM FORECAST SOUNDINGS SHOW A 5KFT SATURATED LAYER NEAR THE SURFACE IN THE EASTERN PORTIONS OF THE FORECAST AREA...ABOUT 2KFT THICK FROM KLBF TO KVTN...AND RELATIVELY SHALLOW IN THE PANHANDLE. THE NAM ALSO INDICATES SOME LIFT AND SATURATION AT THE 300K SURFACE IN THE EASTERN HALF OF THE FORECAST AREA...SO INTRODUCED DRIZZLE BEGINNING 09Z FRIDAY. FARTHER WEST...THE RUC AND GFS WERE AGREEING WITH SATURATION IN THE NEAR SURFACE LAYER. MENTIONED PATCHY FOG FOR THE ENTIRE FORECAST AREA...BUT THINKING THE WESTERN HALF WILL LIKELY EXPERIENCE MORE FOG WHILE EASTERN HALF HAS MORE DRIZZLE AND STRATUS. FOG WILL LIKELY BE MORE WIDESPREAD ALONG THE EDGE OF THE STRATUS...SO UPGRADED TO AREAS OF FOG BETWEEN THE PANHANDLE AND HIGHWAY 83. SURFACE WIND PROFILES WILL ALSO BE MORE FAVORABLE TOWARD FOG FARTHER WEST...AS SPEEDS STAY NEAR 10 MPH WHERE DRIZZLE IS MENTIONED. SOME FOG MAY BE LOCALLY DENSE...BUT AM NOT CONFIDENT ON COVERAGE DUE TO WIND. FRIDAY AFTERNOON...CONTINUED PATCHY DRIZZLE FOR THE EASTERN HALF OF THE FORECAST AREA AS SURFACE WINDS TURN EAST AND ADVECT IN MOIST AIR. FORECAST SOUNDINGS KEEP THE LOW LEVELS NEARLY SATURATED...SO ANY BIT OF LIFT COULD RESULT IN SOME LIGHT PRECIPITATION. TEMPERATURE WISE...LOWERED MIN TEMPS TONIGHT ACROSS THE PANHANDLE FOR MOSTLY CLEAR CONDITIONS AND LIGHT NORTH WINDS. LATEST GUIDANCE HAS LOWER TO MID 40S IN THE WESTERN SANDHILLS...BUT GENERALLY DID NOT GO THAT LOW. BUMPED UP A DEGREE ACROSS NORTH CENTRAL NEBRASKA DUE TO PERSISTENT STRATUS AND HIGHER DEW POINTS. CLOUD COVER WILL LIKELY LEAD TO A LARGE GRADIENT IN MAX TEMPS ACROSS THE FORECAST AREA FRIDAY. THE EASTERN PANHANDLE WILL LIKELY REMAIN UNDER FAIR SKIES...ALLOWING TEMPERATURES TO REACH THE UPPER 70S AND LOWER 80S. UNDER THE STRATUS IN THE EAST...LIMITED HIGHS TO THE LOWER 70S. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 329 PM CDT THU SEP 24 2015 FRIDAY NIGHT THROUGH SUNDAY...THE MAIN FORECAST CHALLENGES IN THE MID RANGE IS FOG POTENTIAL FRIDAY NIGHT...THEN TEMPERATURES. FOR FRIDAY EVENING...THE UPPER LEVEL LOW AND SURFACE LOW WILL DRIFT TO THE SOUTH SOUTHWEST INTO NORTHERN KANSAS. A WEAK SHORTWAVE WILL ROTATE ON THE NORTHWESTERN PERIPHERY OF THE LOW LATE FRIDAY AFTERNOON AND FRIDAY EVENING. ENOUGH WEAK FORCING IS PRESENT TO FACILITATE LOW POPS IN THESE AREAS FRIDAY EVENING. HOWEVER...THE MOIST LAYER IS FAIRLY SHALLOW FRIDAY EVENING AND FRIDAY NIGHT...SO THINKING HERE IS MORE OF A DRIZZLE SETUP FRIDAY EVENING...PARTICULARLY WITH DRYING ALOFT AND WEAK LIFT NOTED IN THE SATURATED LOW LAYER. AFTER LATE EVENING...THE THREAT FOR FOG WILL INCREASE OVERNIGHT AS LIGHT EASTERLY WINDS PERSIST ALONG WITH A VERY MOIST BOUNDARY LAYER. ATTM...THE MAIN AREA OF CONCERN FOR FOG IS WEST OF HIGHWAY 183. EAST OF THIS ROUTE...BUFKIT SOUNDINGS ARE MORE INDICATIVE OF STRATUS AS THE BOUNDARY LAYER IS SOMEWHAT DRIER. ON SATURDAY...THE REMNANTS OF THE LOW WILL FILL IN OVER SRN KS AS A POSITIVELY TILTED RIDGE BUILDS INTO NORTHERN NEBRASKA. SRLY WINDS WILL INCREASE IN THE AFTERNOON...PARTICULARLY IN THE WEST AS SURFACE LOW PRESSURE DEEPENS OVER NERN WYOMING. INCREASED SRLY WINDS...WILL ALLOW CLOUDINESS TO DISPERSE BY MIDDAY SAT ALLOWING HIGHS TO REACH THE UPPER 70S AND LOWER 80S. FOR SATURDAY NIGHT...LOW LEVEL MOISTURE WILL REMAIN PREVALENT ACROSS WESTERN AND NORTH CENTRAL NEBRASKA WITH OVERNIGHT DEW POINTS IN THE MID AND UPPER 50S. EVEN WITH DECENT BL MOISTURE PRESENT SAT NIGHT...AM NOT TOO CONCERNED ABOUT FOG ATTM WITH SRLY WINDS OF 10 TO 15 MPH EXPECTED OVERNIGHT. THE COMBINATION OF WIND AND LOW LEVEL MOISTURE...WILL LEAD TO A MILD NIGHT WITH LOWS IN THE 50S TO AROUND 60. ON SUNDAY...LOW PRESSURE WILL DROP SOUTHEAST INTO THE WESTERN PANHANDLE. SOUTHWESTERLY WINDS WILL INCREASE FURTHER ON SUNDAY AS MUCH WARMER H85 AIR PUSHES INTO THE PANHANDLE AND WESTERN HALF OF THE CWA. INCREASED HIGHS INTO THE UPPER 80S IN THE WEST...AND WOULDN/T BE SURPRISED IF WE SEE A 90+ TEMP IN THE EASTERN PANHANDLE OR FAR SW SUNDAY AFTERNOON GIVEN THE FCST H85 TEMPS OF 25 TO 29C. SUNDAY NIGHT THROUGH THURSDAY...MAINLY DRY CONDS WILL CONTINUE INTO MONDAY WITH HIGHS MAINLY IN THE 80S TO LOWER 90S. A PACIFIC COOL FRONT WILL PUSH INTO THE FORECAST AREA ON MONDAY NIGHT...STALLING OVER SRN NEBRASKA ON TUESDAY. MID LEVEL FRONTOGENESIS WILL INCREASE OVER CENTRAL AND NORTHERN NEBRASKA TUESDAY/TUESDAY NIGHT WITH THE THREAT FOR SHOWERS/TSRAS CONTINUED. BEYOND TUESDAY NIGHT...THE ECMWF AND GFS DIVERGE SIGNIFICANTLY IN THEIR SOLUTIONS. THE ECMWF BUILDS A RIDGE INTO THE CENTRAL CONUS WEDS/THURSDAY...WHICH WOULD LEAD TO DRY AND VERY WARM TEMPERATURES. THE 12Z GFS THIS MORNING HAS A LESS AMPLIFIED SOLUTION ACROSS THE CENTRAL CONUS WITH FAVORABLE JET DYNAMICS FOR PRECIPITATION WEDS THROUGH THURSDAY. INHERITED FCST HAD A MENTION OF PRECIPITATION WEDS-THUS. GIVEN THE MODEL DIFFERENCES...WILL LEAVE IN MENTION OF PCPN TO MAINTAIN A CONSISTENT FORECAST. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 647 PM CDT THU SEP 24 2015 DEPARTING AREA OF LOW PRESSURE WILL HELP TO SPREAD STRATUS AND FOG INTO THE KLBF AND KVTN TERMINALS DURING THE LATE EVENING AND EARLY MORNING HOURS. SOME UNCERTAINTIES EXIST WITH RESPECT TO HOW FAR VISIBILITIES WILL FALL WITHIN THE VICINITY OF THE KLBF AND KVTN TERMINALS TOMORROW MORNING...AS A SUBSTANTIAL LAYER OF STRATUS CLOUDS MAY INHIBIT MAXIMUM RADIATIONAL COOLING NEEDED FOR LOWER VISIBILITIES. WITH THIS BEING SAID...IFR CONDITIONS ARE STILL ANTICIPATED AFTER 06Z AND 08Z AT THE KVTN AND KLBF TERMINALS RESPECTIVELY FROM THE AFOREMENTIONED STRATUS DECK. ANOTHER FACTOR THAT IS WORKING AGAINST SUB IFR VISIBILITIES WILL BE MARGINAL WIND SPEEDS WHICH WILL AIDE IN BOUNDARY LAYER MIXING...AS WELL AS THE NORTHERLY WINDS WHICH ARE GENERALLY DRIER IN NATURE. MVFR CONDITIONS ARE EXPECTED TO RETURN TO THE KVTN AND KLBF TERMINALS NEAR 16Z...AS THE STRATUS DECK BEGINS TO LIFT. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CLB SHORT TERM...DS LONG TERM...CLB AVIATION...MOLDAN
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1045 PM EDT THU SEP 24 2015 .SYNOPSIS... A LOW PRESSURE SYSTEM MOVING SLOWLY ONSHORE INTO COASTAL GEORGIA AND SOUTH CAROLINA TONIGHT...AND HIGH PRESSURE ANCHORED WELL TO THE NORTH...WILL BRING INCREASINGLY WET CONDITIONS AND SLIGHTLY BELOW NORMAL DAYTIME TEMPERATURES FOR THE NEXT FEW DAYS. THE LOW WILL LIFT NORTH LATE IN THE WEEKEND BRINGING A GRADUAL DRYING TREND SUNDAY INTO MONDAY...BUT LOW PRESSURE RISING OUT OF THE GULF OF MEXICO COULD BRING MORE RAIN IN THE UPCOMING WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... AS OF 1030 PM THURSDAY...SYNOPTICALLY LITTLE HAS CHANGED OVER THE PAST FEW HOURS...HOWEVER ON THE MESOSCALE SIDE THERE HAS BEEN A RADICAL RECONFIGURATION OF PRECIPITATION ECHOES OBSERVED ON RADAR. A HUGE DRY SLOT HAS OPENED UP FROM MYRTLE BEACH SOUTHWARD FOR HUNDREDS OF MILES OVER THE OCEAN. THE 00Z RUN OF THE HRRR (NCEP OPERATIONAL RUN...NOT THE EXPERIMENTAL VERSION) SHOWS THIS QUITE WELL AND IS THE BASIS FOR THIS UPDATE. POPS WILL REMAIN HIGH...70-100 PERCENT...BUT RAINFALL AMOUNT FORECASTS HAVE BEEN TRIMMED BACK TO ACCOUNT FOR SPOTTIER SHOWERS OVER THE NEXT 4-6 HOURS. ONCE WE GET TO 5-6 AM A MORE SUSTAINED PERIOD OF SHOWERS MAY DEVELOP ACROSS THE CAPE FEAR REGION. DISCUSSION FROM 730 PM FOLLOWS... LOW PRESSURE IS CENTERED ABOUT 70 MILES EAST OF SAVANNAH ALONG A NEARLY STATIONARY FRONT LINING THE WESTERN WALL OF THE GULF STREAM. CLOSER TO CAPE FEAR THIS FRONT IS VERY NEAR THE LOCATION OF THE FRYING PAN SHOALS BUOY WHERE WIND DIRECTIONS HAVE OSCILLATED FROM SE TO NE OVER THE PAST FEW HOURS. ALTHOUGH THE LOW IS CENTERED OFFSHORE AT THE SURFACE...IT TILTS WESTWARD WITH HEIGHT AND AT 500 MB IS CENTERED OVER CENTRAL GEORGIA. DEEP SOUTH- SOUTHEASTERLY FLOW THROUGHOUT THE 850-500 MB LAYER IS BRINGING PRECIPITABLE WATER VALUES AROUND 2 INCHES UP TO THE CAROLINA COAST. FOR LATE SEPTEMBER THIS EXCEEDS THE 90TH PERCENTILE. AS THE UPPER LEVEL SYSTEM AND SURFACE LOW BOTH MOVE A LITTLE WESTWARD OVERNIGHT THE DEEP FLOW OF MOISTURE OFFSHORE SHOULD BECOME ORIENTED DIRECTLY ACROSS NE SOUTH CAROLINA AND SE NORTH CAROLINA. AS WINDS BECOME PERPENDICULAR TO THE FRONT...ISENTROPIC LIFT BECOMES IMPRESSIVE ALMOST REGARDLESS OF WHICH THETA LEVEL YOU LOOK AT GIVEN THE GREAT DEPTH OF MOISTURE. FORECAST POPS HAVE BEEN INCREASED TO A SOLID 100 PERCENT. IN TERMS OF PRECIP AMOUNTS...THROUGH 8 AM FRIDAY AREAL AVERAGE FORECASTS RANGE FROM ABOUT 0.60 INCHES ALONG THE SANTEE RIVER NEAR GEORGETOWN TO 1.50 INCHES ACROSS THE CAPE FEAR COAST. THERE WILL UNDOUBTEDLY BE CONVECTIVE ENHANCEMENT IN SPOTS WITH LOCALIZED 2-3 INCH TOTALS NOT OUT OF THE QUESTION. RAINFALL DEPARTURES OVER THE PAST THREE WEEKS ARE QUITE LARGE AND WE CAN PROBABLY TAKE 2-3 INCHES OF RAIN WITHOUT PROBLEM OUTSIDE OF TYPICAL URBAN/POOR DRAINAGE PROBLEM AREAS. ENOUGH MOISTURE HAS ADVECTED AROUND THE NORTH SIDE OF THE LOW THAT EVAPORATIONAL COOLING POTENTIAL IS DIMINISHING RAPIDLY. DEWPOINTS ARE NOW IN THE MID 60S EVEN IN DARLINGTON AND BENNETTSVILLE...WITH 70S AT THE NC COAST. AS THE RAIN BEGINS IN EARNEST ACROSS THE INTERIOR PEE DEE REGION OVER THE NEXT FEW HOURS LOOK FOR TEMPERATURES TO SETTLE INTO THE MID-UPPER 60S. IN FACT LOWS SHOULD REACH THE UPPER 60S MOST AREAS...AROUND 70 ON THE COAST. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... AS OF 3 PM THURSDAY...CHIEF WEATHER CAPTION THIS PERIOD...`RAIN`. DEEP TROPOSPHERIC ONSHORE WIND TRAJECTORIES ALREADY UNDERWAY AND POINTING LANDWARD UP THROUGH 30 THOUSAND FEET PER THE LATEST KLTX VAD WIND PROFILE DATA. THE MOST RECENT SATELLITE-DERIVED BLENDED PRECIPITABLE-WATER TRENDS SHOW VALUES OF 53MM-57MM/2.08-2.24 INCHES POISED JUST OFF THE BEACHES AND BLEEDING INTO THE SAVANNAH RIVER VALLEY SOUTH OF THE AREA. SURFACE CONVERGENCE AXIS OFFSHORE WHICH IS DEPICTED WELL IN AN EARLIER 1433Z ASCAT POLAR-ORBITER SWEEP EXTENDING SOUTH TO NORTH FROM OFFSHORE JAX FL TO E OF CAPE LOOKOUT...WILL GRADUALLY SHIFT TOWARD LAND INTO FRIDAY. THIS WILL AID IN CONVECTIVE INITIATION WHILE UPPER WINDS GUIDE CELLS AND DEBRIS RAINS ONSHORE. NO FLOOD WATCH IS PLANNED AT THIS TIME SINCE IT APPEARS BREAKS IN SIGNIFICANT RAIN-RATES WILL TRANSPIRE BETWEEN THE APPRECIABLE RAIN EPISODES...THE EPISODES NAMELY TONIGHT...AND AGAIN DURING THE DAY FRIDAY. SEVERAL IMPULSES WILL SUSTAIN RAIN CHANCES LATE FRIDAY AND SATURDAY BUT IT LOOKS LIKE LOCALLY...THE LOW-LEVEL CONVERGENCE WILL NOT BE AS STRONG AS TONIGHT AND FRIDAY...WHICH COULD STEM THE POTENTIAL ONSLAUGHT OF DEEP CONVECTIVE RAINS. MINIMUMS THIS PERIOD NEAR NORMAL MIDDLE 60S TO LOW 70S CLOSER TO THE SEA...WHEREAS MAXIMUMS WILL RUN 4-6 DEGREES F BELOW NORMAL IN THE MIDDLE AND UPPER 70S. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 3 PM THURSDAY...THE LONG TERM STILL LOOKS CONSIDERABLY CLOUDY AND UNSETTLED ALTHOUGH A WASHOUT IS NOT FORECAST. A VERY SLOW MOVING AND WEAK ATLANTIC SURFACE LOW SHOULD BE CENTERED NEAR CAPE LOOKOUT AT THE START OF THE PERIOD WITH ANY SIGNIFICANT RAINFALL N AND E OF THE CENTER. STRONG HIGH PRESSURE ACROSS NEW ENGLAND WILL WEDGE SOUTHWARD ACROSS THE CAROLINAS AT THE BEGINNING OF THE PERIOD. THE WEDGE IS EXPECTED TO BREAK DOWN WITH HIGH PRESSURE BECOMING CENTERED ACROSS THE CAROLINAS TUE AND WED. A 500 MB LOW WILL BE CUT OFF ACROSS THE SOUTHERN PLAINS WITH WEAK RIDGING DEVELOPING ACROSS THE CAROLINAS...AN EXTENSION OF THE WESTERN ATLANTIC RIDGE SUN THROUGH TUE. SURFACE LOW PRESSURE WILL BE MOVING N THROUGH THE GULF OF MEXICO AND MAY BE NEAR THE NORTHERN GULF COAST TUE-THU. A FRONTAL BOUNDARY WILL BE POSITIONED ACROSS THE OFFSHORE WATERS OF THE SOUTHEAST STATES. DEEP MOISTURE ASSOCIATED WITH GULF OF MEXICO SYSTEM SHOULD BE STREAMING NORTH MID AND LATE WEEK ALTHOUGH TOO EARLY TO SAY HOW WIDESPREAD THE RAINFALL WILL BE ACROSS THE EASTERN CAROLINAS. WILL SHOW LOWEST POPS EARLY IN THE WEEK AND THEN TREND SOMEWHAT HIGHER AS ISENTROPIC UPGLIDE SHOULD BEGIN TO INCREASE. FORECAST CONFIDENCE IS LOWER THAN NORMAL AND DEPENDENT ON EVOLUTION OF LOW PRESSURE IN GULF OF MEXICO. MOST OF THE PERIOD WILL BE DOMINATED BY A COOL NORTHERLY FLOW AND THIS ALONG WITH CONSIDERABLE CLOUD COVER WILL TEND TO SHRINK THE DIURNAL RANGE. HIGHS WILL GENERALLY BE BELOW NORMAL AND LOWS WILL BE ABOVE NORMAL FOR LATE SEPTEMBER. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... AS OF 00Z...WIDESPREAD PRECIP IS ONGOING. A NEARLY STATIONARY FRONTAL BOUNDARY IS STRADDLING THE COAST...WITH NORTHEAST WINDS INLAND AND EASTERLY WINDS AND HEAVIER CONVECTION OFFSHORE. LOOK FOR NEAR IFR OR IFR CONDITIONS THROUGH MOST OF THE FORECAST PERIOD. SOME BRIEF BOUTS OF HEAVY PRECIP ARE POSSIBLE AT ALL TERMINALS THROUGH THE OVERNIGHT HOURS...HOWEVER EXPECT PREDOMINATELY LIGHT TO MODERATE RAIN UNTIL THE WINDS SHIFT TO THE EAST...PROBABLY NOT UNTIL AFTER DAYBREAK ON FRIDAY. THIS WILL BE THE BEST TIME FOR THE HEAVIER CONVECTION. EXTENDED OUTLOOK...INTERMITTENT IFR CONDITIONS ARE POSSIBLE THROUGH SATURDAY. IMPROVING CONDITIONS SUNDAY AND MONDAY WITH DETERIORATING CONDITIONS AGAIN LATE TUESDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM THURSDAY...AFTER CHATTING WITH NWS METEOROLOGISTS IN MOREHEAD CITY AND CHARLESTON WE HAVE AGREED TO EXPAND THE SMALL CRAFT ADVISORY TO INCLUDE ALL OF THE SOUTH CAROLINA COAST...AND EXTEND IT IN TIME UNTIL 4 AM FRIDAY MORNING. WIND GUSTS AT MYRTLE BEACH HAVE RECENTLY INCREASED TO 27 KNOTS AT SPRINGMAID PIER. THIS SURGE OF STRONGER WINDS WILL LIKELY PERSIST FOR ANOTHER 3-4 HOURS BEFORE DIMINISHING. GUSTS CONTINUE TO REACH 25 KNOTS AT WRIGHTSVILLE BEACH WITH WINDS NEARLY 30 KNOTS OUT AT THE BUOY 25 MILES OFFSHORE. AS WE SAW LAST NIGHT...THE CONFIGURATION OF THE PRESSURE GRADIENT IS SUPPORTING STRONGER WINDS UP AGAINST THE COAST RATHER THAN FARTHER OFFSHORE. DISCUSSION FROM 730 PM FOLLOWS... LOW PRESSURE IS CENTERED ABOUT 70 MILES EAST OF SAVANNAH ALONG A NEARLY STATIONARY FRONT LINING THE WESTERN WALL OF THE GULF STREAM. CLOSER TO CAPE FEAR THIS FRONT IS VERY NEAR THE LOCATION OF THE FRYING PAN SHOALS BUOY WHERE WIND DIRECTIONS HAVE OSCILLATED FROM SE TO NE OVER THE PAST FEW HOURS. BETWEEN THE FRONT AND THE COAST THE PRESSURE GRADIENT HAS BECOME PINCHED TIGHTLY AND WIND GUSTS ARE IN THE APPROACHING 30 KT BETWEEN CAPE FEAR AND CAPE LOOKOUT. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE SE NORTH CAROLINA COASTAL WATERS UNTIL MIDNIGHT. RECENTLY OBSERVED WIND GUSTS INCLUDE 27 KNOTS AT WRIGHTSVILLE BEACH...28 KNOTS AT THE NEARSHORE WRIGHTSVILLE BEACH CORMP BUOY. FOR THE SC COASTAL WATERS THE PRESSURE GRADIENT IS WEAKER AND WINDS ARE MORE IN THE 15-20 KT RANGE...HOWEVER IT REMAINS TO BE SEEN WHAT WIND SPEEDS WILL DO AS THE OFFSHORE FRONT APPROACHES OVERNIGHT. SEAS ARE CURRENTLY AS HIGH AS 5.2 FEET AT THE HARBOR BUOY SOUTH OF SOUTHPORT...AND ARE STILL 6.6 FEET AT FRYING PAN. THESE WAVE HEIGHTS SHOULD PEAK IN THE NEXT COUPLE OF HOURS WITH WAVES DIMINISHING BELOW 6 FEET BY MIDNIGHT. SHORT TERM/ FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 PM THURSDAY...ALTHOUGH NOT IDEAL AND MODERATELY BUMPY AT TIMES...NO ADVISORIES ARE PLANNED FRIDAY AND SATURDAY. SEAS ARE EXPECTED TO HOLD IN A 3-5 FOOT RANGE AND WINDS AROUND 15 KT. AN EXERCISE CAUTION STATEMENT MAY BE NEEDED SATURDAY AFTERNOON AND NIGHT AS SLIGHT STRENGTHENING OF HIGH PRESSURE TO THE NORTH INCREASES NE WINDS IN THE 15-20 KT RANGE. ISOLATED TSTMS CAN BE EXPECTED ON THE WATERS BOTH DAYS AND MARINERS SHOULD CHECK RADAR TRENDS BEFORE HEADING OUT. DOMINANT WAVE PERIODS WILL BE MIXED BETWEEN LONGER PERIOD ESE WAVES 2-3 FEET EVERY 10-11 SECONDS AND E WAVES 2-3 FEET EVERY 7-8 SECONDS...BOTH THESE WAVE GROUPS TO CO- MINGLE WITH A MODERATE NE CHOP. LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 3 PM THURSDAY...A MUCH MORE RELAXED PRESSURE GRADIENT...AS COMPARED TO RECENT DAYS...SHOULD BE IN PLACE SUNDAY AS WEAK LOW PRESSURE WILL BE MOVING PROGRESSIVELY N OF THE WATERS. THE WEDGE WILL BUILD STRONGLY SOUTH-SOUTHWEST WITH ITS ASSOCIATED TIGHTER PRESSURE GRADIENT REMAINING LARGELY W OF THE WATERS. HIGHEST WIND SPEEDS...UP TO 10 TO 15 KT SUN...SHOULD BE 10 KT OR LESS FOR THE REMAINDER OF THE FORECAST PERIOD. A NE OR ENE WIND DIRECTION WILL DOMINATE. SEAS WILL BE MAINLY 2 TO 3 FT ALTHOUGH SPOTTY 4 FT SEAS ACROSS THE OUTERMOST NORTHERN WATERS ARE POSSIBLE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT FRIDAY FOR AMZ250-252-254- 256. && $$ SYNOPSIS... NEAR TERM...TRA SHORT TERM...MJC LONG TERM...RJD AVIATION...DL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
631 PM EDT WED SEP 23 2015 .SYNOPSIS... BROAD HIGH PRESSURE WILL EXTEND OVER THE AREA FROM THE NORTH THROUGH THE WEEKEND. LOW PRESSURE OFFSHORE TO THE SOUTHEAST WILL MOVE SOUTHWEST THROUGH THURSDAY...AND THEN WEST FRIDAY. LOW PRESSURE WILL MOVE NORTHEAST OVER THE AREA THIS WEEKEND AND AWAY FROM THE AREA EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... AS OF 630 PM WEDNESDAY...NO REAL CHANGE TO THE WEATHER PATTERN THAT HAS GRIPPED THE REGION THIS WEEK. HIGH PRESSURE RIDGING SOUTH INTO THE CAROLINAS IS PRODUCING A DAMMING/WEDGE SURFACE PATTERN WHILE A WEAK/BROAD AREA OF LOW PRESSURE OFFSHORE IS SLOWLY RETROGRESSING TOWARD THE SOUTHEAST COAST. AS BEEN THE THE CASE THE PAST SEVERAL DAYS THE MOST DIFFICULT PORTION OF THE FORECAST CONCERNS DETERMINING THE LOCATION, TIMING, AND AMOUNTS OF PRECIPITATION. THE MODELS HAVE BEEN TOO AGGRESSIVE THE PAST 3 DAYS IN FORECASTING PRECIPITATION ACROSS EASTERN NC. THUS WILL DECREASE POPS FOR THE EVENING HOURS TO 20-30% AS RADAR INDICATES WHAT LITTLE PRECIPITATION THERE IS WAS LOCATED MAINLY OFFSHORE. WILL MAINTAIN CURRENT 30-50% POPS AFTER MIDNIGHT AND CONTINUE TO MONITOR PRECIPITATION TRENDS BUT THESE MAY BE OVERDONE AND MAY NEED TO BE DECREASED WITH THE 10 PM UPDATE. L0W TEMPERATURES OVERNIGHT WILL RANGE FROM THE MID 60S FAR WEST TO LOWER 70S COAST WITH OVERCAST SKIES AND GUSTY NORTHEAST WINDS. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... AS OF 315 PM WEDNESDAY...GOOD AGREEMENT AMONGST THE GFS/NAM12 AND ECMWF REGARDING HIGH LIKELIHOOD OF PRECIPITATION TOMORROW AS SURFACE LOW AS SURFACE LOW MOVES WEST AND MID/UPPER LEVEL LOW SLOWLY PULLS NORTHEAST FROM THE CENTRAL GULF COAST. GOOD MOISTURE FLUX AND ISENTROPIC LIFT SHOULD LEAD TO WIDESPREAD LIGHT TO MODERATE RAIN ACROSS THE REGION...PRIMARILY IN THE AFTERNOON HOURS THURSDAY. CLOUD COVER AND PRECIPITATION WILL HOLD MAXIMUM TEMPERATURES GENERALLY IN THE MID/UPPER 70S. RAINFALL AMOUNTS SHOULD AVERAGE ONE QUARTER TO ONE HALF INCH. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... AS OF 230 PM WED...A COMPLEX FORECAST CONTINUES ACROSS EASTERN NC BRINGING WET AND BREEZY TO WINDY CONDITIONS THROUGH MUCH OF THE WEEKEND. THURSDAY NIGHT...MDLS SHOW OFFSHORE CSTL TRF BECOMING LESS DEFINED AND SHIFTING TOWARD THE COAST. PLENTY OF MOISTURE WILL CONT TO STREAM ACRS THE REGION WITH PRECIP WTR VALUES NEAR 2 INCHES. WILL HAVE LIKELY POPS ALL AREAS AS MDLS SHOW GOOD QPF OVER THE REGION WITH INCREASED UPPER LEVEL DIFFLUENCE. CLOUDS AND PRECIP WILL KEEP TEMPS MILD WITH LOWS IN THE MID TO UPPER 60S INLAND AND LOWER 70S BEACHES. FRIDAY THROUGH SUNDAY...NUMEROUS SHOWER...SOME HEAVY EXPECTED INTO SUNDAY AS DEEP MOISTURE PERSISTS OVER THE REGION WITH SFC TRF IN THE AREA AND WEAK DIFL ALOFT. CONT LIKELY POPS THRU SAT NIGHT AND SEVERAL INCHES OF RAINFALL WILL BE POSS IN SPOTS ESPCLY COAST. SOME DIFF IN MDLS CONT LATER IN WEEKEND WITH GFS QUICKER TO LIFT SFC LOW AND DEEPER MOISTURE N OF THE REGION SUNDAY. FOR NOW CONT PREV FCST WITH CHC POPS SUNDAY GIVEN UNCERTAINTY. WIDESPREAD CLOUDS AND PRECIP WILL KEEP TEMPS STEADY THRU SUNDAY WITH MILD LOWS IN 60S TO LOWER 70S WITH HIGHS MOSTLY IN THE 75 TO 80 DGR RANGE. MONDAY THRU WED...LOW PRES PROGGED TO MOVE NE OF THE AREA EARLY NEXT WEEK WITH A DRYING TREND AS THE DEEP MOISTURE LIFTS NORTH OF THE AREA AND HIGH PRES BUILDS IN FROM THE WEST. TEMPS WARM SLIGHTLY WITH GREATER INSOLATION EXPECTED AND EXPECT HIGHS IN THE LOWER 80S. && .AVIATION /22Z WEDNESDAY THROUGH MONDAY/... SHORT TERM /THROUGH 00Z THURSDAY/... AS OF 630 PM WEDNESDAY...EXPECTING VARIABILITY AT THE INLAND (ISO/PGV) TAF SITES THIS EVENING FROM MVFR TO VFR CEILINGS WHILE MVFR CEILINGS PERSIST AT OAJ AND EWN. LATER TONIGHT THE MODELS INDICATE THAT THE LOW LEVEL FLOW WILL VEER FROM NORTHEAST TO EAST AND MOISTEN THE LOW LEVELS. MOIST OF THE NUMERICAL AVIATION GUIDANCE IS INDICATING IFR CEILINGS DEVELOPING LATE TONIGHT (AFTER 06Z) WHILE THE NARRE AND HRRR GUIDANCE ARE AT ODDS WITH THIS. DUE TO THIS UNCERTAINTY WILL MAINTAIN A MVFR CEILING FORECAST AND CONTINUE TO MONITOR. ON THURSDAY WE ARE EXPECTING MORE WIDESPREAD SHOWER ACTIVITY AND EXPECT A CONTINUATION OF MVFR CEILINGS. LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AS OF 230 PM WED...POOR FLYING THRU MUCH OF THE WEEKEND. DEEP MOISTURE OVER THE AREA WITH LEAD TO BOUTS OF SHRA WITH PROLONGED PDS PERIODS OF SUB VFR CONDITIONS LIKELY...WITH SOME IFR EXPECTED. MOISTURE BEGINS TO DIMINISH LATER SUN AND ESPCLY MON WITH LESS SHRA AND PROB MORE VFR. && .MARINE... SHORT TERM /THROUGH THU/... AS OF 630 PM WEDNESDAY...GUSTY N/NE WINDS AND ROUGH SEAS WILL PERSIST THROUGH THURSDAY WITH LOW PRESSURE OFFSHORE AND STRONG HIGH PRESSURE LOCKED OVER THE NORTHEAST. THE LOW SHOULD SLOWLY START TO DRIFT TOWARD THE SOUTHEAST COAST LATE TONIGHT DECREASING THE GRADIENT AND WINDS SHOULD DIMINISH A BIT INTO THURSDAY...BUT PER LOCAL SWAN/NWPS...SEAS SHOULD REMAIN ELEVATED. CURRENTLY...WINDS ARE GUSTING TO AROUND 30 KNOTS WITH SEAS 6 TO 10 FEET. AS WITH THE WINDS...SEAS WILL SUSBIDE A BIT ON THURSDAY BUT SHOULD STILL REMAIN IN THE 6 TO 8 FOOT RANGE AT MOST LOCATIONS. LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AS OF 230 PM WED...HIGH CONFIDENCE IN POOR BOATING CONDITIONS FOR MUCH OF THE LONG TERM AS PERSISTENT MODERATE TO OCNLY STRONG NE/E WINDS AND ROUGH SEAS WILL DOMINATE. THE TWO MAIN FEATURES ARE PERSISTENT HIGH PRESSURE THAT WILL BE ANCHORED TO THE NORTH AND AN ELONGATED AREA OF LOW PRESSURE OFF THE SE COAST THAT WILL PRODUCE A TIGHT PRESSURE GRADIENT. THE LOW WILL MOVE ONSHORE TO THE SOUTH OF ENC ON THURSDAY INTO FRIDAY, WITH WINDS 15-25KT WITH SEAS 4-8 FT HIGHEST NORTH. MODELS ARE STILL NOT IN THE BEST AGREEMENT WITH THE NEXT SYSTEM THIS WEEKEND. GFS QUICKLY LIFTS LOW OVER AND N OF REGION SUNDAY WHILE ECMWF KEEPS IT TO THE S THRU SUNDAY WHICH LEADS TO LONGER PERIOD OF STRONGER ONSHORE WINDS. CONT PREV FCST WITH MODERATE ONSHORE FLOW CONT INTO SUNDAY. SEAS EXPECTED TO BUILD TO 8 TO 11 FT CNTRL AND N AND 4 TO 6 FEET S THRU THE WEEKEND. MDLS DIFFER A BIT WITH WIND DIR EARLY NEXT WEEK BUT AGREE ON DIMINISHING WINDS...MAINLY FROM A NRLY DIR. AS WINDS DIMINISH SEAS WILL SUBSIDE TO 4 TO 6 FT N AND 3 TO 5 FT S LATER MON. && .TIDES/COASTAL FLOODING... AS OF 325 PM WEDNESDAY...THE HIGH SURF ADVISORY HAS BEEN EXTENDED THROUGH THURSDAY AFTERNOON. PERSISTENT NORTHEAST WINDS WILL CONTINUE TO PRODUCE 6 TO 9 FOOT SURF ALONG WITH A HIGH THREAT OF RIP CURRENTS AND POSSIBLE BEACH EROSION. UNCERTAINTY CONTINUES THIS WEEKEND...BUT ROUGH SEAS AND STRONG NE WINDS ARE POSSIBLE...ESPECIALLY SATURDAY. IN ADDITION TO THE OCEANSIDE IMPACTS, SOUNDSIDE LOCATIONS VULNERABLE TO STRONG NE WINDS COULD SEE MINOR WATER LEVEL RISES, WHICH WOULD BE EXACERBATED BY THE HIGH ASTRONOMICAL TIDES THIS WEEKEND INTO EARLY NEXT WEEK. STAY TUNED TO LATER FORECASTS AS HOPEFULLY CONFIDENCE INCREASES. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...HIGH SURF ADVISORY UNTIL 6 PM EDT THURSDAY FOR NCZ103. MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT THURSDAY FOR AMZ130-131- 135. SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR AMZ150-152-154. SMALL CRAFT ADVISORY UNTIL 8 PM EDT THURSDAY FOR AMZ156-158. && $$ SYNOPSIS...CTC NEAR TERM...JME/CTC SHORT TERM...CTC LONG TERM...RF AVIATION...RF/JME MARINE...RF/JME/CTC TIDES/COASTAL FLOODING...CTC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
320 AM EDT WED SEP 23 2015 .SYNOPSIS... HIGH PRESSURE WELL TO THE NORTH WILL KEEP WINDS OUT OF THE NORTHEAST. THIS AIRMASS WILL BECOME INCREASINGLY OVERRUN BY ATLANTIC TROPICAL MOISTURE AS THE WEEK PROGRESSES FOLLOWED BY A GRADUAL ABATING TREND LATER IN THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1030 PM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST THIS EVENING. A SOLID LOW OVERCAST HAS DEVELOPED ACROSS MOST OF EASTERN NORTH CAROLINA. THIS SHOULD MAINTAIN CLOUDY SKIES THROUGH SUNRISE EAST OF I-95...WITH CLOUDINESS INCREASING OVER THE NEXT COUPLE HOURS WEST OF I-95. THE LAST SEVERAL HRRR RUNS SHOW SHOWERS/SPRINKLES DEVELOPING INLAND BETWEEN 06-08Z...2-4 AM WEDNESDAY...POTENTIALLY MAKING IT AS FAR WEST AS DARLINGTON AND BENNETTSVILLE. WHILE I`M NOT SHOWING PRECIPITATION THAT FAR INLAND A SMALL POP WILL BE MAINTAINED NEAR THE COAST FOR MEASURABLE PRECIP LATE...WITH NON-MEASURABLE SCATTERED SPRINKLES ELSEWHERE. DISCUSSION FROM 730 PM FOLLOWS... LOW PRESSURE OFF THE CAROLINA COAST HAS MULTIPLE CENTERS AS OBSERVED ON VISIBLE SATELLITE IMAGERY EARLIER IN THE AFTERNOON. MOST OF THE SYNOPTIC MODELS AVERAGE OUT THOSE SWIRLS TO A COMMON CENTER NEAR 32.0N AND 75.3W. WEST OF THE LOW THE PRESSURE GRADIENT IS QUITE INTENSE AS HIGH PRESSURE OVER THE NORTHERN TIER OF STATES IS PUNCHING SOUTH THROUGH THE SOUTHERN APPALACHIANS. THIS GRADIENT SHOULD ACTUALLY INTENSIFY A BIT FURTHER OVERNIGHT... MAINTAINING A HEALTHY NORTH TO NORTHEAST BREEZE THROUGH THE NIGHT. WIND GUSTS AT THE BEACHES COULD EASILY REACH 30 MPH. ATLANTIC MOISTURE BROUGHT ONSHORE BY THE NORTHEAST WINDS EXTENDS UP THROUGH ABOUT 9000 FEET WITH A DRY SUBSIDENCE INVERSION ALOFT. EVEN AS MOISTURE ADVECTS ONSHORE TONIGHT THIS SUBSIDENCE INVERSION SHOULD KEEP MOISTURE LIMITED IN THE VERTICAL EXTENT WHICH WILL PRECLUDE ANY POTENTIAL FOR THUNDERSTORMS OR EVEN DEEP SHOWERS. AWAY FROM THE COAST I IMAGINE ANY PRECIPITATION WILL LIKELY TAKE THE FORM OF SPRINKLES WITH LITTLE POTENTIAL FOR MEASURABLE TOTALS. ISENTROPIC ANALYSIS ACTUALLY SHOWS DOWNGLIDE THROUGH THE 295K-300K LAYER WHICH WILL FURTHER LIMIT POTENTIAL FOR SIGNIFICANT RAINFALL...AT LEAST THROUGH TONIGHT. WITH CLOUDS AND A STEADY BREEZE EXPECTED TO CONTINUE OVERNIGHT NO SIGNIFICANT CHANGES HAVE BEEN MADE TO LOW TEMPERATURES...STILL ANTICIPATED TO REACH THE UPPER 60S TO NEAR 70. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY... MID LEVEL LOW REMAINS NEARLY STATIONARY ON THURSDAY JUST NORTH OF FLORIDA BIG BEND. SPRAWLING HIGH PRESSURE NORTH OF NEW YORK STATE BRINGS A NORTHEASTERLY FLOW INTO THE CAROLINAS. EASTERLY FLOW JUST ATOP THIS SURFACE LAYER WILL CAUSE INCREASING OVERRUNNING OF ATLANTIC MOISTURE AND RISING RAIN CHANCES. THIS WILL BE ESPECIALLY TRUE AS THE DAY WEARS ON AND A HEALTHY VORT MAX ROTATES ASHORE AROUND THE FLORIDA LOW. THE MID LEVEL LOW WEAKENS AND RETROGRADES ON FRIDAY BUT MANY OF THE AFOREMENTIONED RAIN-MAKING PLAYERS REMAIN IN PLACE I.E. MAINLY THE LOW LEVEL FLOW OVERRUNNING THE NORTHEASTERLY SURFACE WEDGE. LOOKING AT THE RH FIELDS OF THE MODELS IT SEEMS THAT FRIDAY WILL OFFER A LONGER FETCH OF MOISTURE OUT OF THE BAHAMAS WHEN COMPARED TO TUESDAY. FRIDAY APPEARS TO OFFER UP NOT ONLY HIGHER POPS OVERALL BUT ALSO WHEN THE RAIN MAY BECOME HEAVY AT TIMES, LASTING INTO FRIDAY NIGHT. OVERRUNNING RAINS DO NOT SUFFER A DIURNAL CYCLE LIKE CONVECTION OFTEN DOES. IN FACT A STRONGER AND/OR DEEPER NOCTURNAL SURFACE LAYER CAN BOLSTER THE EFFECTS OF ISENTROPIC UPGLIDE. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 3 AM WEDNESDAY... MUCH OF THE ACTION MAY BE SHIFTING TO OUR NORTH OVER THE WEEKEND. MODELS NOW SHOWING LOW DEVELOP OFFSHORE AND MOVE NORTHWARD AND PUSHING THE EASTERLY FLOW ALONG WITH IT. RAIN WILL LIKELY LAST INTO SATURDAY ALBEIT WITH LOWER QPF PROSPECTS AND THIS TREND WILL CONTINUE INTO SUNDAY AS LITTLE ONSHORE FLOW REMAINS ATOP THE STALWART SURFACE WEDGE. IN FACT WITH LITTLE TO SCOUR OUT THE LOW LEVEL MOISTURE THE REMAINDER OF THE FORECAST MAY REMAIN A BIT MORE CLOUDY THAN TYPICAL LATE SEPTEMBER WEATHER AND JUST A TAD ON THE COOL SIDE. SIMILARLY IT WILL BE HARD TO PROMISE A RAIN-FREE DAY THOUGH MOST OF WHAT FALLS MAY NOT BE IN THE FORM OF MEASURABLE RAINFALL AS OPPOSED TO TRACE AMOUNT SPRINKLES. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 05Z...NOT MUCH CHANGE NEEDED BASED ON THE PREVIOUS 00Z TAF ISSUANCE FORECAST. THUS PERSISTENCE WILL BE THE WORD HERE. MAIN WEATHER CONCERNS FOR THIS FORECAST PERIOD WILL CONCENTRATE ON THE BORDERLINE WINDY CHARACTERISTIC OF THE WINDSPEEDS... ESPECIALLY ALONG THE CAROLINA COASTS. AND THE OTHER FLY IN THE OINTMENT ARE THE LOW MVFR/IFR CEILINGS. MODELS TAKE A WEAK...TO MODEST AT BEST...AREA OF LOW PRESSURE OFF THE SE COAST AND DRIFT IT BACK OR RETROGRADE IT TO THE SOUTHWEST DURING THE NEXT FEW DAYS. WITH STRONG HIGH PRESSURE CENTERED OVER THE NE STATES...AND RIDGING EXTENDING SOUTH ALONG THE SPINE OF THE APPALACHIANS. THE 2 FEATURES COMBINED WILL RESULT IN A TIGHTENED SFC PRESSURE GRADIENT ACROSS THE FORECAST AREA RESULTING IN 360-030 WIND DIRECTIONS AT 10 TO 20 KT SPEEDS...WITH HIER GUSTS IN EXCESS OF 25 KT AT TIMES. THE HIER END OF THE RANGE OF WIND SPEEDS AND GUSTS WILL PRIMARILY OCCUR ACROSS THE COASTAL TERMINALS. AS THE LOW DRIFTS CLOSER TO THE CAROLINA COASTS...LOW CLOUDS WILL BECOME MORE DOMINANT AND PERSIST THROUGHOUT THE TAF ISSUANCE PERIOD RESULTING IN MVFR AND PERHAPS IFR CEILINGS. PATCHY LIGHT RAIN OR DRIZZLE WILL ALSO BECOME THE FAVORABLE PCPN TYPE. EXTENDED OUTLOOK...INCREASING CHANCES OF MVFR/IFR CEILINGS AND REDUCED VSBY THURSDAY DUE TO INCREASING CHANCES OF SHOWERS/ISOLATED THUNDERSTORMS. MAINLY VFR FRIDAY INTO SATURDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST WITH THIS LATE EVENING UPDATE. SEAS ARE CURRENTLY 8 FEET AT THE FRYING PAN SHOALS BUOY BUT SHOULD NOT BUILD SIGNIFICANTLY HIGHER. DISCUSSION FROM 730 PM FOLLOWS... WINDS OVER THE PAST FEW HOURS HAVE BEEN RUNNING TOWARD THE UPPER END OF THE MODEL GUIDANCE ENVELOPE. GUSTS WITHIN THE PAST FEW HOURS HAVE REACHED 31 KNOTS AT THE OFFSHORE WRIGHTSVILLE BEACH BUOY...29 KNOTS AT THE FRYING PAN SHOALS BUOY...25 KNOTS AT THE SUNSET BEACH BUOY...AND 24 KNOTS AT WRIGHTSVILLE BEACH. MODEL CONSENSUS IS WINDS SHOULD INCREASE BY ANOTHER 3-5 KNOTS OVERNIGHT...GIVING VERY SOLID SMALL CRAFT ADVISORY CONDITIONS ALL THE WAY UP TO THE BEACHES. BASED ON RECENTLY OBSERVED WAVE HEIGHTS AND AN 18Z RUN OF THE LOCAL SWAN MODEL...OUR FORECAST SEAS HAVE BEEN INCREASED BY ABOUT A FOOT...WITH 8-FOOTERS NOW EXPECTED IN THE 10-20 MILES ZONE EAST OF CAPE FEAR. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY... THE WEDGE OF HIGH PRESSURE IN PLACE WILL BE THE DOMINANT WIND MAKER THROUGH THE PERIOD. THIS WILL KEEP THE FLOW OUT OF THE NORTHEAST. WITH WHATEVER IS LEFT OF THE OFFSHORE LOW SUNKEN TO OUR SOUTH AND/OR DISSIPATED THE GRADIENT MAY NOT BE ALL THAT PINCHED AND THUS MODERATE AT WORST. THIS LIKELY KEEPS WIND AND SEAS BELOW ADVISORY LEVELS. THE SURFACE RIDGE WELL TO OUR NORTH WEAKENS SLIGHTLY ON FRIDAY PERHAPS KNOCKING A FEW KNOTS OFF THE WIND SPEED. FRIDAY AND FRIDAY NIGHT MAY SEE SOME HEAVY RAIN ACROSS THE AREA MAKING FOR LIMITED VISIBILITY. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 3 AM WEDNESDAY... NORTHEASTERLY WINDS WILL REMAIN IN PLACE AS THE PATTERN OVERALL IS VERY NON-PROGRESSIVE. THIS KEEPS THE HIGH WELL TO OUR NORTH WITH ONLY SOME SENSE OF EASTWARD DRIFT. A WEAK COASTAL TROUGH MAY DEVELOP AND LEND SOME COMPLICATION TO THE WIND FORECAST AS ITS PRESENCE MAY VEER US TO MORE EASTERLY AND BRING LOWER SPEEDS THAN CURRENTLY FORECAST. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR AMZ250-252- 254-256. && $$ SYNOPSIS... NEAR TERM...TRA SHORT TERM...MBB LONG TERM...MBB AVIATION...DCH/MAC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
126 AM EDT WED SEP 23 2015 .SYNOPSIS... STRONG HIGH PRESSURE TO THE NORTH WILL CONTINUE TO EXTEND INTO THE CAROLINAS THIS WEEK INTO THE UPCOMING WEEKEND. LOW PRESSURE OFFSHORE OF THE CAROLINAS WILL BEGIN DRIFT BACK TOWARD THE COAST...BREEZY AND WET WEATHER DEVELOPING LATER THIS WEEK INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1030 PM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST THIS EVENING. A SOLID LOW OVERCAST HAS DEVELOPED ACROSS MOST OF EASTERN NORTH CAROLINA. THIS SHOULD MAINTAIN CLOUDY SKIES THROUGH SUNRISE EAST OF I-95...WITH CLOUDINESS INCREASING OVER THE NEXT COUPLE HOURS WEST OF I-95. THE LAST SEVERAL HRRR RUNS SHOW SHOWERS/SPRINKLES DEVELOPING INLAND BETWEEN 06-08Z...2-4 AM WEDNESDAY...POTENTIALLY MAKING IT AS FAR WEST AS DARLINGTON AND BENNETTSVILLE. WHILE I`M NOT SHOWING PRECIPITATION THAT FAR INLAND A SMALL POP WILL BE MAINTAINED NEAR THE COAST FOR MEASURABLE PRECIP LATE...WITH NON-MEASURABLE SCATTERED SPRINKLES ELSEWHERE. DISCUSSION FROM 730 PM FOLLOWS... LOW PRESSURE OFF THE CAROLINA COAST HAS MULTIPLE CENTERS AS OBSERVED ON VISIBLE SATELLITE IMAGERY EARLIER IN THE AFTERNOON. MOST OF THE SYNOPTIC MODELS AVERAGE OUT THOSE SWIRLS TO A COMMON CENTER NEAR 32.0N AND 75.3W. WEST OF THE LOW THE PRESSURE GRADIENT IS QUITE INTENSE AS HIGH PRESSURE OVER THE NORTHERN TIER OF STATES IS PUNCHING SOUTH THROUGH THE SOUTHERN APPALACHIANS. THIS GRADIENT SHOULD ACTUALLY INTENSIFY A BIT FURTHER OVERNIGHT... MAINTAINING A HEALTHY NORTH TO NORTHEAST BREEZE THROUGH THE NIGHT. WIND GUSTS AT THE BEACHES COULD EASILY REACH 30 MPH. ATLANTIC MOISTURE BROUGHT ONSHORE BY THE NORTHEAST WINDS EXTENDS UP THROUGH ABOUT 9000 FEET WITH A DRY SUBSIDENCE INVERSION ALOFT. EVEN AS MOISTURE ADVECTS ONSHORE TONIGHT THIS SUBSIDENCE INVERSION SHOULD KEEP MOISTURE LIMITED IN THE VERTICAL EXTENT WHICH WILL PRECLUDE ANY POTENTIAL FOR THUNDERSTORMS OR EVEN DEEP SHOWERS. AWAY FROM THE COAST I IMAGINE ANY PRECIPITATION WILL LIKELY TAKE THE FORM OF SPRINKLES WITH LITTLE POTENTIAL FOR MEASURABLE TOTALS. ISENTROPIC ANALYSIS ACTUALLY SHOWS DOWNGLIDE THROUGH THE 295K-300K LAYER WHICH WILL FURTHER LIMIT POTENTIAL FOR SIGNIFICANT RAINFALL...AT LEAST THROUGH TONIGHT. WITH CLOUDS AND A STEADY BREEZE EXPECTED TO CONTINUE OVERNIGHT NO SIGNIFICANT CHANGES HAVE BEEN MADE TO LOW TEMPERATURES...STILL ANTICIPATED TO REACH THE UPPER 60S TO NEAR 70. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...PRIMARY WEATHER HEADLINE THIS PERIOD TO KICK OFF AUTUMN IS MOUNTING CHANCES OF APPRECIABLE RAINFALL ACCOMPANIED BY MAXIMUM TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL WITH CONSIDERABLE CLOUDS. SURFACE HIGH PRESSURE WILL STRENGTHEN NORTH OF THE GREAT LAKES THIS PERIOD...PRESSING A DAMMING WEDGE SOUTHWARD INTO THE CAROLINAS. CONCURRENTLY A WESTERN ATLANTIC SURFACE LOW WILL RETROGRADE AND FILL MOVING WSW ONTO THE CAROLINA COAST THURSDAY INTO FRIDAY. THE DEEP ONSHORE FLOW AND LOW-LEVEL ISENTROPIC OMEGA SHOULD HELP SPUR GOOD CHANCES OF STRATIFORM RAIN THU AFTN/NIGHT. SEVERAL MODERATE LOBES OF H7-H5 VORTICITY ARE FORECAST TO ROTATE ONSHORE THURSDAY WHICH COULD SPAWN ISOLATED EMBEDDED CONVECTION. PRECIPITABLE WATERS WILL BECOME ELEVATED BY THURSDAY WITH DEEP E-SE WIND FLOW SURFACE TO 400 MB. IT APPEARS INTO THURSDAY NIGHT THE THREAT OF LOCALIZED EXCESSIVE RAINFALL MAY COME INTO PLAY OVERNIGHT INTO EARLY FRIDAY. STRONG HIGH PRESSURE TO THE NORTH AND ANTICIPATED CLOUD COVER SHOULD KEEP MAXIMUMS IN THE UPPER 70S TO LOWER 80S THIS PERIOD AND MINIMUMS MIDDLE 60S INLAND AND AROUND 70 CLOSE TO THE COAST. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 3 PM TUESDAY...INCREASING CONFIDENCE IN A HEAVY RAINFALL EVENT THIS WKND AS AN AREA OF DISTURBED TROPICAL/SUBTROPICAL WEATHER RETROGRADES BACK TOWARDS THE COAST. THIS OCCURS IN RESPONSE TO AN UPPER LOW WHICH IS WEAKENING AND DRIFTING WELL WEST AS IT GETS TRAPPED WITHIN A COL NEAR A LARGE UPPER RIDGE. THE ECMWF LATCHED ONTO THE HEAVY RAIN IDEA YESTERDAY...AND NOW THE GFS AND CANADIAN ARE FOLLOWING SUIT. THIS IS LIKELY DUE TO THE WEAKER AND FURTHER WEST MOTION OF THE UPPER LOW...WHICH IS ALLOWING THE `FLOOD GATES` TO OPEN TO THE DEEP TROPICAL MOISTURE OFFSHORE. 850MB U-WIND ANOMALIES REACH -4 SD`S (!) DUE TO THE EASTERLY WIND (NEGATIVE SINCE WIND IS A VECTOR...THIS CAN STILL BE CONSIDERED A POSITIVE SIGNAL) WHICH FLOODS MOISTURE RIGHT INTO THE CAROLINAS WHERE PWATS CLIMB TO OVER 2 INCHES...AND WEAK UPPER DIFFLUENCE DEVELOPS AS A JET ENTRANCE REGION BLOSSOMS TO OUR NORTH. ADDITIONALLY...THE PRESSURE GRADIENT TIGHTENS WHICH DRIVES INCREASING WINDS...AND FORCES STRONGER ISENTROPIC LIFT AT 310 AND 315 K ATOP THE INLAND WEDGE. ALL THIS SUGGESTS PERIODS OF HEAVY RAINFALL ARE POSSIBLE FRI..SAT...AND SUN...BEFORE A BACK DOOR FRONT SINKS SOUTH AND THE UPPER LOW WEAKENS...CAUSING DRYING LOCALLY. WPC QPF PAINTS 3-5" ACROSS THE EASTERN NC COAST...WITH SOMEWHAT LESSER AMOUNTS SW. SEE NO REASON TO MOVE AWAY FROM THESE FORECAST VALUES FOR NOW BUT THERE IS STILL PLENTY OF TIME TO REFINE THE FORECAST. EARLY NEXT WEEK MAY STILL BE UNSETTLED BUT OVERALL WILL BE MUCH DRIER. TEMPS FRI-SUN WILL FEATURE LOW DIURNAL RANGES WITH HIGHS SLIGHTLY BELOW CLIMO AND LOWS JUST ABOVE. MORE SEASONABLE TEMPERATURES ARE EXPECTED EARLY NEXT WEEK. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 05Z...NOT MUCH CHANGE NEEDED BASED ON THE PREVIOUS 00Z TAF ISSUANCE FORECAST. THUS PERSISTENCE WILL BE THE WORD HERE. MAIN WEATHER CONCERNS FOR THIS FORECAST PERIOD WILL CONCENTRATE ON THE BORDERLINE WINDY CHARACTERISTIC OF THE WINDSPEEDS... ESPECIALLY ALONG THE CAROLINA COASTS. AND THE OTHER FLY IN THE OINTMENT ARE THE LOW MVFR/IFR CEILINGS. MODELS TAKE A WEAK...TO MODEST AT BEST...AREA OF LOW PRESSURE OFF THE SE COAST AND DRIFT IT BACK OR RETROGRADE IT TO THE SOUTHWEST DURING THE NEXT FEW DAYS. WITH STRONG HIGH PRESSURE CENTERED OVER THE NE STATES...AND RIDGING EXTENDING SOUTH ALONG THE SPINE OF THE APPALACHIANS. THE 2 FEATURES COMBINED WILL RESULT IN A TIGHTENED SFC PRESSURE GRADIENT ACROSS THE FORECAST AREA RESULTING IN 360-030 WIND DIRECTIONS AT 10 TO 20 KT SPEEDS...WITH HIER GUSTS IN EXCESS OF 25 KT AT TIMES. THE HIER END OF THE RANGE OF WIND SPEEDS AND GUSTS WILL PRIMARILY OCCUR ACROSS THE COASTAL TERMINALS. AS THE LOW DRIFTS CLOSER TO THE CAROLINA COASTS...LOW CLOUDS WILL BECOME MORE DOMINANT AND PERSIST THROUGHOUT THE TAF ISSUANCE PERIOD RESULTING IN MVFR AND PERHAPS IFR CEILINGS. PATCHY LIGHT RAIN OR DRIZZLE WILL ALSO BECOME THE FAVORABLE PCPN TYPE. EXTENDED OUTLOOK...INCREASING CHANCES OF MVFR/IFR CEILINGS AND REDUCED VSBY THURSDAY DUE TO INCREASING CHANCES OF SHOWERS/ISOLATED THUNDERSTORMS. MAINLY VFR FRIDAY INTO SATURDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST WITH THIS LATE EVENING UPDATE. SEAS ARE CURRENTLY 8 FEET AT THE FRYING PAN SHOALS BUOY BUT SHOULD NOT BUILD SIGNIFICANTLY HIGHER. DISCUSSION FROM 730 PM FOLLOWS... WINDS OVER THE PAST FEW HOURS HAVE BEEN RUNNING TOWARD THE UPPER END OF THE MODEL GUIDANCE ENVELOPE. GUSTS WITHIN THE PAST FEW HOURS HAVE REACHED 31 KNOTS AT THE OFFSHORE WRIGHTSVILLE BEACH BUOY...29 KNOTS AT THE FRYING PAN SHOALS BUOY...25 KNOTS AT THE SUNSET BEACH BUOY...AND 24 KNOTS AT WRIGHTSVILLE BEACH. MODEL CONSENSUS IS WINDS SHOULD INCREASE BY ANOTHER 3-5 KNOTS OVERNIGHT...GIVING VERY SOLID SMALL CRAFT ADVISORY CONDITIONS ALL THE WAY UP TO THE BEACHES. BASED ON RECENTLY OBSERVED WAVE HEIGHTS AND AN 18Z RUN OF THE LOCAL SWAN MODEL...OUR FORECAST SEAS HAVE BEEN INCREASED BY ABOUT A FOOT...WITH 8-FOOTERS NOW EXPECTED IN THE 10-20 MILES ZONE EAST OF CAPE FEAR. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM TUESDAY...DIFFICULT MARINE CONDITIONS THIS PERIOD AS MODERATE AND STRONG NE WINDS PREVAIL. STRENGTHENING HIGH PRESSURE EXTENDING SOUTH INTO THE CAROLINAS WILL INTERACT WITH AN OFFSHORE LOW DRIFTING BACK TOWARD THE CAROLINA COAST. NHC HAS 10 PERCENT CHANCE OF THE SYSTEM DEVELOPING INTO A TROPICAL ENTITY. CURRENT SMALL CRAFT ADVISORIES THROUGH 6AM THU MAY NEED TO EVENTUALLY BE EXTENDED BEYOND THIS FOR SEAS TO RECOVER. STRONGEST WINDS 20-30 KT TO PREVAIL WED THROUGH EARLY THU. MAXIMUM SEA HEIGHTS 5-7 FEET WED AFTERNOON AND EVENING. ISOLATED TSTMS CAN BE EXPECTED AND MARINERS SHOULD GET RADAR UPDATES BEFORE VENTURING OUT. LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 3 PM TUESDAY...POOR MARINE CONDITIONS MUCH OF THE EXTENDED AS PERSISTENT NE FLOW CONTINUES AND INTENSIFIES...ESPECIALLY ON SATURDAY. TROUGH OF LOW PRESSURE OFFSHORE WILL BACK UP TO THE COAST THIS WKND...AT THE SAME TIME HIGH PRESSURE BEGINS TO WEDGE DOWN THE COAST. THIS WILL CAUSE A TIGHTENING OF THE GRADIENT ACROSS THE WATERS...WITH NE WINDS AROUND 10-15 KTS FRIDAY RISING TO 15-20 KTS SATURDAY...BEFORE SLOWLY EASING DURING SUNDAY. THIS WILL DRIVE AN AMPLIFYING NE WIND WAVE...ESPECIALLY SATURDAY INTO SUNDAY...WHEN WAVE HEIGHTS WILL REACH 4-5 FT AND THEN ONLY VERY SLOWLY DROP OFF ON SUNDAY. SEAS FRIDAY WILL RISE SLOWLY FROM 2-4 FT EARLY TO 3-5 FT LATE. CAUTIONARY STATEMENTS WILL LIKELY BECOME NECESSARY SATURDAY...AND IT IS NOT OUT OF THE QUESTION THAT ADVISORY HEADLINES MAY INSTEAD BE NEEDED THIS WKND. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR AMZ250-252- 254-256. && $$ SYNOPSIS... NEAR TERM...TRA SHORT TERM...MJC LONG TERM...JDW AVIATION...DCH/MAC MARINE...
AREA FORECAST DISCUSSION
NWS BISMARCK ND
949 PM CDT THU SEP 24 2015 .UPDATE... ISSUED AT 941 PM CDT THU SEP 24 2015 LATEST HRRR IS NOT AS AGGRESSIVE IN SPREADING LOW STRATUS INTO WESTERN NORTH DAKOTA. IT DOES BRING SOME LOW STRATUS INTO THE SOUTHWEST AROUND 08-10 UTC THEN DISSIPATES. THINK THE INCREASING SOUTHERLY FLOW AND INCREASING HIGH CLOUDS IS ATTRIBUTING TO THE DISSIPATING STRATUS HERE. STRATUS/FOG DOES EXPAND ACROSS CENTRAL NORTH DAKOTA AFTER MIDNIGHT TO INCLUDE JAMESTOWN BISMARCK AND POSSIBLY MINOT...WITH MAX COVERAGE AROUND 13 UTC. WILL UPDATE CLOUD COVER USING THE LATEST HRRR AS GUIDANCE. OTHERWISE NO SIGNIFICANT UPDATES NEEDED. UPDATE ISSUED AT 621 PM CDT THU SEP 24 2015 LATEST SURFACE ANALYSIS SHOWS SURFACE LOW PRESSURE OVER NORTHEAST NEBRASKA WITH A SURFACE RIDGE EXTENDING EAST TO WEST ALONG THE INTERNATIONAL BORDER. THIS WILL KEEP A SOUTH TO SOUTHEAST OVER THE FORECAST AREA TONIGHT. WITH ABUNDANT LOW LEVEL MOISTURE OVER THE AREA EXPECT AREAS OF FOG TO DEVELOP ONCE AGAIN TONIGHT. A LIMITING FACTOR MAY BE A SHORTWAVE TRACKING THROUGH WESTERN CANADA...OVER THE UPPER LEVEL RIDGE. THIS WILL BRING INCREASING LOW LEVEL SOUTHERLY FLOW TO ESPECIALLY WESTERN NORTH DAKOTA LATE TONIGHT. THERE MAY BE ENOUGH TURBULENCE IN THE LOWER LEVELS TO INHIBIT WIDESPREAD FOG DEVELOPMENT IN THE WEST. FOR NOW WILL KEEP WITH THE GOING FORECAST OF AREAS OF FOG ACROSS WESTERN AND CENTRAL NORTH DAKOTA. WILL HIT LOWER CIGS/VISIBILITIES AT KBIS AND KJMS IN THE TAF FORECAST. ONLY MINOR ADJUSTMENTS TO SKY COVER WITH THE EARLY EVENING UPDATE AND POPULATED LATEST SENSIBLE WEATHER ELEMENTS. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 250 PM CDT THU SEP 24 2015 CURRENT SURFACE ANALYSIS PLACES LOW OVER NORTHEAST NEBRASKA INTO SOUTHEAST SOUTH DAKOTA BRINGING LIGHT SOUTH/SOUTHEASTERLY LOW LEVEL FLOW OVER OUR AREA. UPPER LEVEL ANALYSIS PLACES LOW SLOWLY SLIDING FROM THE CENTRAL PLAINS INTO THE UPPER MIDWEST WITH RIDGE OVER THE WESTERN DAKOTAS/EASTERN MONTANA. LOW CLOUDS CONTINUE TO LINGER OVER PORTIONS OF THE AREA WITH MOIST LOW LEVEL FLOW...OTHERWISE QUIET CONDITIONS CONTINUE. FOR TONIGHT...EXPECT AREAS OF FOG TO RE-DEVELOP OVER THE AREA BY LATE THIS EVENING WITH AMPLE LOW LEVEL MOISTURE IN PLACE. OTHERWISE...A QUIET NIGHT IS EXPECTED AS UPPER RIDGE REMAINS OVER THE AREA. ON FRIDAY...FOG WILL LINGER INTO THE EARLY MORNING HOURS BEFORE DISSIPATING. OTHERWISE...A QUIET DAY IS EXPECTED WITH TEMPERATURES PUSHING ABOVE AVERAGE WITH UPPER RIDGE IN PLACE. SOUTHERLY WINDS WILL INCREASE BY MID DAY INTO THE AFTERNOON AS SURFACE LOW FORMS AND STARTS TO DEEPEN ON THE LEE SIDE OF THE ROCKIES. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 317 PM CDT THU SEP 24 2015 DRY AND WARM THROUGH SATURDAY AS OUR FLOW ALOFT REMAINS WEAK AND SOUTHWESTERLY. JET STREAM MIGRATES SOUTHWARD LATER THIS COMING WEEKEND INTO EARLY NEXT WEEK AND WILL STEER EMBEDDED MID LEVEL WAVES THROUGH THE LOCAL REGION...GIVING US A CHANCE FOR SHOWERS SAT NIGHT THROUGH TUESDAY. COOLER TEMPERATURES AS WELL...BUT STILL SEASONAL. MODELS THEN PORTRAY A STRONG SURFACE HIGH MOVING THROUGH THE REGION MID-WEEK AND SHOULD RESULT IN MAINLY DRY CONDITIONS AND PLEASANT TEMPERATURES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 941 PM CDT THU SEP 24 2015 AREAS OF FOG WILL RE-DEVELOP TONIGHT BRINGING IFR/LIFR CIGS AND VIS ACROSS CENTRAL NORTH DAKOTA...AND POSSIBLY PORTIONS OF THE WEST. WITH AN INCREASING SOUTHERLY FLOW FROM WEST TO EAST...THINK CONDITIONS IMPROVE FIRST IN THE WEST AND OVER HIGHER TERRAIN. CONDITIONS SHOULD IMPROVE OVER THE CENTRAL BY MID-MORNING FRIDAY. VFR CONDITIONS EXPECTED THEREAFTER. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TWH SHORT TERM...JJS LONG TERM...NH AVIATION...TWH
AREA FORECAST DISCUSSION
NWS PORTLAND OR
900 PM PDT THU SEP 24 2015 .SYNOPSIS...A FRONT EXTENDING FROM THE NORTH WASHINGTON COAST AND SOUTHWEST OVER THE OREGON COASTAL WATERS THIS EVENING WILL SLOWLY PUSH EAST TO SOUTHEAST TONIGHT AND FRIDAY. MOST RAINFALL WILL OCCUR OVERNIGHT THROUGH FRIDAY MORNING...PRIMARILY OVER SW WASHINGTON AND THE NORTH OREGON COAST. ANY REMAINING MOISTURE WILL DECREASE FRIDAY NIGHT AND SATURDAY. THE ASSOCIATED TRAILING UPPER TROUGH WILL SPLIT AS IT APPROACHES THE COAST THIS WEEKEND...LEAVING THE REGION WITH DRY WEATHER AND NEAR NORMAL TEMPS. DURING THE EARLY TO MIDDLE PART OF THE NEXT WEEK AN UPPER LOW OFF THE CA COAST IS EXPECTED TO WANDER N BRINGING THE NEXT CHANCE FOR SHOWERS. && .SHORT TERM...MINIMAL CHANGES TO THE FORECAST THIS EVENING. WATER VAPOR IMAGERY SHOWED AN UPPER TROUGH AXIS FROM ABOUT 52N 139W TO 40N 142W THIS EVENING. BAROCLINIC BOUNDARY EXTENDING FROM VANCOUVER ISLAND TO A DEVELOPING WAVE AT 41N 136W. THIS WAVE SHOWING DEFINITE SIGNS OF DEEPENING WITH A WELL-DEFINED INFLECTION POINT WITH ANOTHER CIRCULATION ROUNDING THE TROUGH BASE. WOULD TEND TO BELIEVE THIS WAVE WOULD SLOW UP THE EASTWARD PROGRESSION. THE 00Z NAM BRUSHES THE FAR N OREGON WITH SOME MINIMAL QPF AROUND 06Z...WITH VERY LITTLE MOVEMENT INLAND BY 12Z. CURRENT 06Z-12Z POP GRID MAY BE OVERDONE BUT WILL LET MID SHIFT MAKE FINAL EDITS. THE 02Z HRRR SEEMS A BIT MORE OPTIMISTIC BY SHOWING SOME FORECAST 30-35 DBZ REFLECTIVITY RETURNS OVER THE N OREGON COAST RANGE AND INTO THE SW WA WILLAPA HILLS AT 09Z. BELIEVE THIS MAY BE A LITTLE TOO FAST BASED ON CURRENT SATELLITE TRENDS. BAROCLINIC ZONE FALLS APART FRI AFTERNOON. THE ECMWF CONTINUES TO BE MORE MOIST... MAINTAINING THE BAROCLINIC ZONE THROUGH FRI MORNING THEN WEAKENING IT IN THE AFTERNOON. THE EC TIME HEIGHT CROSS SECTIONS SUGGEST MOISTURE MAY BE A LIMITING FACTOR BY FRI AFTERNOON AND EVENING. DID NOT CHANGE POPS FRI AND FRI NIGHT...BUT HAVE A FEELING THE INTERIOR VALLEYS WILL NOT SEE ANYTHING FRI AFTERNOON. THE REMNANT UPPER TROUGH EVENTUALLY DRIFTS SOUTHEAST OVER THE WEEKEND. MODELS SHOW THE TROUGH SPLITTING AS IT APPROACHES THE AREA. 18Z GFS RUN SEEMS A BIT ODD DEVELOPING A CLOSED LOW OFF THE S WA AND N OREGON COAST SAT NIGHT...THEN SWINGING IT INLAND SUN. THE 12Z ECMWF AND LATEST NAM DO NOT SHOW THIS TREND. IN ANY EVENT...THE WEEKEND LOOKS DRY WITH MAX TEMPERATURES AT OR JUST SLIGHTLY BELOW NORMAL. WEISHAAR .LONG TERM....SUNDAY NIGHT THROUGH THURSDAY...MODELS CONTINUE TO SHOW A SLITTING TROUGH PATTERN OVER THE REGION WITH A CUT OFF LOW OFF NORTHERN CALIFORNIA THROUGH EARLY NEXT WEEK. WEAK UPPER LEVEL RIDGING LOOKS TO BRIEFLY NOSE INTO THE REGION LATE SUNDAY AND MONDAY WHICH WILL LIKELY BRING DRIER AND WARMER WEATHER. THE CUT OFF LOW LOOKS TO BEGIN SLOWLY MOVING INTO THE REGION MONDAY WHICH SHOULD BRING SOME CONVECTIVE SHOWERS LATE MONDAY AND TUESDAY. MODELS DIVERGE SIGNIFICANTLY ON WEDNESDAY...BUT IT APPEARS WE WILL LIKELY CONTINUE TO SEE SOME CONVECTIVE SHOWERS AHEAD OF AN APPROACHING FRONT LATE NEXT WEEK. TEMPERATURES THROUGHOUT THE EXTENDED REMAIN NEAR SEASONAL NORMALS. /64 && .AVIATION...SLOW MOVING COLD FRONT WILL CONTINUE TO DRIFT ONSHORE OVERNIGHT TONIGHT...THOUGH MAY STALL A BIT OVER THE COMING HOURS AS LOW PRESSURE DEVELOPS ALONG THE FRONT WELL OFF THE SOUTHERN OREGON COAST. NONETHELESS...MVFR CIGS AND -RA HAVE SPREAD DOWN THE WA COAST TO KHQM...AND ARE EXPECTED TO MOVE INTO KAST BY 06Z. VFR CONDITIONS WILL LIKELY HOLD ON FOR A FEW MORE HOURS AT KONP... BUT LIGHT ONSHORE FLOW AND LOW-LEVEL MOISTURE SHOULD RESULT IN LOW MVFR OR IFR CIGS/VSBYS THERE BY 11Z. A SHIFT TO NORTHERLY WINDS IS EXPECTED BY FRI MORNING BEHIND THE FRONT...AND COULD GUST UP TO 20 KT ALONG THE COAST BY MIDDAY FRI. INLAND AREAS WILL REMAIN VFR THROUGH THE NIGHT WITH BKN HIGH CLOUDS...WITH CIGS LOWERING BUT REMAINING VFR THROUGH FRI MORNING. ISOLD -SHRA POSSIBLE FRI FOR THE INLAND TERMINALS AS THE REMNANTS OF THE FRONT MOVE INLAND...BUT MOST OF THE PRECIPITATION IS EXPECTED TO REMAIN ALONG AND WEST OF THE COAST RANGE AND CIGS/VSBYS SHOULD REMAIN VFR. KPDX AND APPROACHES...VFR AND LIGHT WINDS WILL PREVAIL TONIGHT... WITH HIGH CLOUDS GRADUALLY LOWERING FRI MORNING BUT LIKELY TO REMAIN ABOVE 4000 FT. A FEW -SHRA ARE POSSIBLE FRI...WITH INCREASING N WINDS LIKELY IN THE AFTERNOON. WEAGLE && .MARINE...A VERY SLOW MOVING COLD FRONT WILL CONTINUE TO DRIFT ONSHORE ALONG THE PAC NW COAST TONIGHT...BRINGING A SHIFT FROM LIGHT-MODERATE S WINDS TO INCREASING N WINDS BY FRI MORNING. SEAS GENERALLY REMAIN 4-6 FT WITH SOMEWHAT OF A MIX BETWEEN W-NW AND SW SWELLS. HIGH PRESSURE WILL RETURN TO THE NE PACIFIC THIS WEEKEND AS THERMAL LOW PRESSURE BUILDS OVER NORTHERN CALIFORNIA INTO SOUTHERN OREGON...THOUGH LINGERING UPPER LEVEL TROUGHINESS OFFSHORE MAY TEMPER THE N WINDS A BIT FROM WHAT THEY WOULD OTHERWISE BE IN THIS TYPE OF SURFACE PATTERN. NONETHELESS...EXPECT BREEZY NORTHERLY WINDS OVER THE COASTAL WATERS...LIKELY REACHING LOWER END ADVISORY CRITERIA AT TIMES ESPECIALLY OVER THE CENTRAL OREGON WATERS SOUTH OF NEWPORT. SEAS WILL REMAIN AROUND 6 TO 8 FEET BUT WILL BECOME INCREASINGLY DOMINATED BY WIND WAVE AND SOMEWHAT CHOPPY IN RESPONSE TO THE INCREASING WINDS. ROUGH BAR ADVISORY REMAINS IN PLACE FOR THE COLUMBIA BAR...AS EBB CURRENTS ARE STRENGTHENING AS WE APPROACH THE NEXT FULL MOON. WITH OPPOSING SWELL STILL RATHER SMALL AND SPLIT INTO TWO DIRECTIONS... THIS WILL BE A VERY MARGINAL EVENT WITH MAX SEAS ON THE BAR PROBABLY AROUND 8 FT WITH A FEW BREAKERS HERE AND THERE. WEAGLE && .PQR WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. PZ...SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 1 AM TO 5 AM PDT FRIDAY. && $$ INTERACT WITH US VIA SOCIAL MEDIA WWW.FACEBOOK.COM/NWSPORTLAND WWW.TWITTER.COM/NWSPORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1008 PM EDT THU SEP 24 2015 .SYNOPSIS... AN AREA OF LOW PRESSURE NEAR THE ATLANTIC COASTLINE WILL FEED MOISTURE-RICH AIR INTO THE REGION THROUGH MOST OF THE WEEKEND... RESULTING IN A LENGTHY STRETCH OF WIDESPREAD LIGHT TO MODERATE RAINFALL. DRIER CONDITIONS WILL PREVAIL HEADING INTO LATE SUNDAY AND EARLY NEXT WEEK. && .NEAR TERM /THROUGH FRIDAY/... AS OF 10 PM...RAINFALL CONTINUES ACROSS ALL COUNTIES IN THE CWA. SINCE 9 PM...RADAR RAINFALL ESTIMATES AND AUTOMATED RAIN GAUGES INDICATED THAT RAINFALL RATES IN THE HEAVIEST SHOWERS RANGED NEAR ONE HALF OF AN INCH PER HOUR...WITH COMMON VALUES AROUND 0.3 INCHES. ONE HOUR FFG REMAINS SLIGHTLY ABOVE 3 IN / HR FOR MOST AREAS. MODEL QPF WITHIN RIVER MODELING INDICATE THAT THE LARGER RIVERS APPEAR IN LITTLE THREAT OF FLOODING THROUGH FRI AM. AT 2Z...TCLT VWP INDICATED THAT WINDS AROUND 5 KFT HAVE INCREASED TO 40 KTS. IR SATELLITE AND RADAR INDICATED A SIGNIFICANT CLUSTER OF MODERATE TO HEAVY RAIN DEVELOPING OVER THE MIDLANDS...TRACKING TOWARD THE UPPER SAVANNAH RIVER VALLEY. THE UPSLOPE FLOW...DEEP ISENTROPIC LIFT...AND EXPANDING Q-VECTOR CONVERGENCE WILL INCREASE RAINFALL RATES TONIGHT. FOR THE UPDATE...I WILL INCREASE POPS TO TRIPLE DIGITS AND CLICK QPF A LITTLE HIGHER. NEARLY STEADY TEMPERATURES WILL REMAIN TONIGHT. AS OF 8 PM...VERY IMPRESSIVE STREAM OF WATER VAPOR...FROM SOUTH OF CUBA NORTH ACROSS THE WESTERN CAROLINAS. BLENDED TOTAL PW PRODUCT INDICATES A PLUME OF GREATER THAN 2 INCHES BUILDING WEST ACROSS THE COASTAL PLAIN. NAM AND RAP INDICATES THAT LLVL WINDS WILL INCREASE FROM THE EAST...STRENGTHENING TO AROUND 30 KTS. THE LLVL FLOW WILL CREATE WIDESPREAD LIFT OVER A SFC RIDGE AND ALONG THE EAST FACING SLOPES. IN ADDITION...GFS40 SHOWS A FIELD OF Q-VECTOR CONVERGENCE DEVELOPING ACROSS THE CWA...ON THE NE SIDE OF A CLOSED MID LEVEL LOW. THERE IS NO QUESTION THAT RAINFALL WILL INCREASE ACROSS THE CWA DURING THE OVERNIGHT HOURS. I WILL UPDATE TO INCREASE POPS TO 100 PERCENT...OR VERY CLOSE TO IT. TEMPERATURES MAY REMAIN NEARLY STEADY THROUGH THE REST OF TONIGHT. AS OF 530 PM...LATEST SATELLITE LOOP SHOWS A BAND OF DEEP CONVECTION OFF THE CENTRAL SC SHORE...DRIFTING NORTHWARD. A BAND OF COLDER CLOUD TOPS HAS PIVOTED BACK TOWARD THE COAST...RESULTING IN WARMING CLOUD TEMPERATURES ACROSS THE MIDLANDS OF SC AND CENTRAL GA. BASED ON THE SATELLITE TRENDS...THE CURRENT BAND OF LIGHT RAINFALL MAY SLIDE TOWARD THE WEST...FOLLOWED BY CLUSTERS OF LIGHT RAIN HEADED INTO THIS EVENING. THE ENVIRONMENT BECOMES MORE DYNAMIC LATER THIS EVENING AND OVERNIGHT. NAM AND RAP FORECAST SOUNDINGS INDICATE A DEEP LAYER OF EAST LLVL FLOW ACROSS THE WESTERN CAROLINAS. PWS WILL INCREASE TO NEARLY 2 INCHES WITH THE WARM CLOUD LAYER DEEPENING TO AROUND 13 KFT. IN ADDITION...GFS40S SHOWS A FIELD OF Q-VECTOR CONVERGENCE DEVELOPING ACROSS THE CWA... ON THE NE SIDE OF A CLOSED MID LEVEL LOW. I WILL UPDATE THE FORECAST TO ADJUST POP TIMING AND INCREASE QPF ACROSS THE UPSLOPE AREAS. AT 230 PM EDT THURSDAY...AN UPPER LOW OVER THE SE AND AND ASSOCIATED SURFACE LOW OVER OFF THE GA COAST WILL CONTINUE TO SEND MOISTURE INLAND TOWARD THE BLUE RIDGE TONIGHT AND FRIDAY. THE COMBINATION OF DIFFLUENT FLOW ALOFT...INCREASING EASTERLY LOW LEVEL UPSLOPE FLOW...INCREASING EASTERLY ISENTROPIC UPGLIDE OVER A SURFACE RIDGE...AND MOISTURE WELL ABOVE NORMAL...WILL FAVOR THE DEVELOPMENT OF HEAVY PRECIPITATION ALONG THE EAST FACING BLUE RIDGE. ALTHOUGH MUCH OF THE AREA IS CURRENTLY IN DROUGHT...LOCALIZED FLOODING COULD OCCUR IN SMALLER STREAM BASIN AND HILLY TERRAIN. A FLASH FLOOD WATCH WILL BE NOT ISSUED OUR BLUE RIDGE AREA...AS IT APPEARS PRECIPITANT WILL GRADUALLY SPREAD NE FROM THE UPPER SAVANNAH RIVER VALLEY TO THE NC MOUNTAINS. TEMPERATURES WILL RUN BELOW NORMAL IN COOL NE SURFACE FLOW...ESPECIALLY MAXIMUMS UNDER CLOUD COVER. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... AS OF 255 PM THURSDAY...ALTHOUGH GUIDANCE CONTINUES TO SHOW WIDESPREAD RAIN AT THE START OF THE PERIOD THEN GRADUALLY DIMINISHING IN COVERAGE BY THE END OF THE PERIOD...THEY HAVE BACKED OFF ON AMOUNT OF QPF. MANY OF THE TRADITIONAL PARAMETERS NEEDED FOR FLOODING TYPE RAINFALL ARE NOT THERE. OPS MDLS SHOW PW VALUES ARE UP TO 190 PERCENT OF NORMAL...BUT THE ENSEMBLE GUIDANCE SHOWS 1 TO MAYBE 1.5 STANDARD DEVIATIONS ABOVE NORMAL. WHILE THERE IS SOME UPPER DIVERGENCE ASSOCIATED WITH THE UPPER JET MAX...1 STD DEVIATION ABOVE NORMAL...THIS DISSIPATES ON SAT AS THE JET MOVES OUT OF THE AREA. THE MAIN FORCING WILL COME FROM STRONG UPSLOPE FLOW WITH THE ENSEMBLE GUIDANCE SHOWING H85 ELY FLOW UP TO 4 STD DEVIATIONS ABOVE NORMAL. THERE WILL ALSO BE STRONG ISENTROPIC LIFT IN THE VERY MOIST LOW LEVELS. THE ENSEMBLE GUIDANCE CONTINUES TO SHOW A NORTHWARD SHIFT IN THE BEST H85 FLOW THRU THE PERIOD...ALTHOUGH THE SREF DOES KEEP IT OVER OUR PORTION OF THE BLUE RIDGE LONGER THAN THE GEFS. GIVEN THESE FACTORS...WPC HAS DROPPED THE QPF FCST ACROSS THE AREA. HAVE FOLLOWED THESE TRENDS AS WELL. THAT SAID...THIS STILL PUTS 1 TO 3 INCHES OF RAIN ACROSS AND NEAR THE NRN BLUE RIDGE...SO WILL HAVE TO KEEP AN EYE ON THE RAINFALL AMOUNTS. CANNOT RULE OUT FLOODING... BUT IT APPEARS TO NOT BE WIDESPREAD AND WARRANT A WATCH AT THIS TIME. HIGHEST POPS WILL BE ALONG AND NEAR THE BLUE RIDGE THRU THE PERIOD...WITH LOWER POP ACROSS THE SWRN CWFA. WITH A WEDGE PATTERN IN PLACE AND CONTINUED RAINFALL...EXPECT BREEZY AND COOL CONDITIONS EACH DAY. HIGHS WILL BE NEARLY 10 DEGREES BELOW NORMAL ON SAT THEN RISE A COUPLE OF DEGREES SUN. LOWS WILL BE ABOUT 5 DEGREES ABOVE NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AS OF 230PM THURSDAY...THE EXTENDED PERIOD BEGINS ON SUNDAY NIGHT WITH THE WEEKEND RAINFALL EVENT ON THE WANE AND DRIER CONDITIONS BUILDING IN ACROSS THE FORECAST AREA. WHILE FLOW ALOFT WILL BE SOUTHERLY THANKS TO A CUT-OFF 500MB LOW OVER SOUTH TEXAS AND AN ANTICYCLONE OVER THE WESTERN SARGASSO SEA...SURFACE HIGH PRESSURE AND A LACK OF NOTABLE SHORTWAVES IN THE FLOW ALOFT SHOULD KEEP THE AREA MOSTLY DRY THROUGH MIDDAY TUESDAY. THEREAFTER...THERE IS GENERAL AGREEMENT THAT A LONGWAVE TROUGH WILL MOVE ACROSS THE NORTHERN HALF OF THE U.S. AND CANADA AND AN ASSOCIATED SURFACE LOW PRESSURE SYSTEM AND ATTENDANT COLD FRONT WILL APPROACH OUR AREA ON WEDNESDAY. BOTH THE GFS AND THE ECMWF ARE NOT EXCITED ABOUT NOTABLE RAINFALL AS A RESULT OF THE FRONTAL PASSAGE...HOWEVER...THE GFS CONTINUES TO BE BULLISH ON A MODEST BUT WELL-DEFINED SURFACE LOW MOVING NORTHWARD OVER THE CENTRAL GULF AND APPROACHING THE LOUISIANA COAST BY TUESDAY AFTERNOON. THE ECMWF WEAKENS THE LOW TO AN OPEN TROUGH OVER THE NORTHERN GULF. BOTH MODELS DO NOT BRING THE FEATURE INLAND...HOWEVER THE GFS KEEPS THE SOUTHERN APPALACHIANS IN A MOISTURE-RICH ENVIRONMENT WITH A TROPICAL CONNECTION TO THE CARIBBEAN AND EJECTS ROUNDS OR BANDS OF CONVECTIVE PRECIP NORTH FROM THE GULF LOW ACROSS THE DEEP SOUTH AND INTO OUR AREA BEGINNING TUESDAY EVENING AND LASTING THROUGH WEDNESDAY. THE ECMWF PERSISTS WITH WEAK NORTHEASTERLY FLOW ACROSS MUCH OF THE SOUTHEAST HEADING INTO THURSDAY. AT THIS TIME THE FORECAST MAINTAINS SLIGHT CHANCE TO CHANCE POPS DURING THE MID-WEEK PERIOD GIVEN THE DECENT MOISTURE THAT REMAINS IN PLACE FOLLOWING THE EVENT ENDING ON SUNDAY...THE ANTICIPATED FRONTAL PASSAGE...AND THE PERSISTENCE OF BOTH MODELS OVER THE PAST FEW RUNS OF SUGGESTING SOME ACTIVITY IN THE GULF MOVING TOWARDS THE COAST. NEVERTHELESS...BOTH THE ECMWF AND GFS AGREE THAT A STRONG 1028MB SURFACE HIGH BUILDS IN ACROSS THE NORTHEAST U.S. ON THE CONFLUENT SIDE OF THE UPPER-LEVEL LONGWAVE TROUGH AND WEDGES DOWN ACROSS MUCH OF THE SOUTHEAST U.S.... SIGNIFICANTLY DRYING US OUT THROUGH THE END OF THE PERIOD ON FRIDAY MORNING. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... AT KCLT AND ELSEWHERE...VERY IMPRESSIVE STREAM OF WATER VAPOR...FROM SOUTH OF CUBA NORTH ACROSS THE WESTERN CAROLINAS. BLENDED TOTAL PW PRODUCT INDICATES A PLUME OF GREATER THAN 2 INCHES BUILDING WEST ACROSS THE COASTAL PLAIN. NAM AND RAP INDICATES THAT LLVL WINDS WILL INCREASE FROM THE EAST...STRENGTHENING TO AROUND 30 KTS. THE LLVL FLOW WILL CREATE WIDESPREAD LIFT OVER A SFC RIDGE AND ALONG THE EAST FACING SLOPES. THERE IS NO QUESTION THAT RAINFALL WILL INCREASE ACROSS THE CWA DURING THE OVERNIGHT HOURS. IN ADDITION...FORECAST SOUNDINGS CONTINUE TO INDICATE LOWERING CLOUD BASES TONIGHT. I WILL TIME RESTRICTIVE CEILINGS DEVELOPING THIS EVENING...REACHING IFR DURING THE PREDAWN HOURS. HEAVIER RAINFALL RATES SHOULD KEEP VIS IN THE LVFR TO MVFR RANGE THROUGH MOST OF THE 0Z TAF PERIOD. WINDS WILL REMAIN FROM THE NE...LIKELY GUSTY LATE TONIGHT THROUGH THE DAYLIGHT HOURS FRIDAY. OUTLOOK...DEEP MOISTURE AND WIDESPREAD LIFT WILL LIKELY RESULT IN RESTRICTIVE CEILINGS AND VISIBILITY PERIODICALLY THRU SATURDAY. IN ADDITION...RAINFALL WILL BE MODERATE TO HEAVY AT TIMES THROUGH SATURDAY. CONFIDENCE TABLE... 02-08Z 08-14Z 14-20Z 20-00Z KCLT HIGH 83% HIGH 100% HIGH 95% HIGH 97% KGSP MED 78% MED 72% HIGH 93% HIGH 91% KAVL MED 77% MED 79% MED 70% HIGH 95% KHKY HIGH 93% HIGH 100% HIGH 100% HIGH 95% KGMU HIGH 84% HIGH 91% HIGH 87% HIGH 100% KAND MED 73% MED 69% HIGH 83% HIGH 95% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...JMP NEAR TERM...NED SHORT TERM...RWH LONG TERM...JMP AVIATION...NED
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
811 PM EDT THU SEP 24 2015 .SYNOPSIS... AN AREA OF LOW PRESSURE NEAR THE ATLANTIC COASTLINE WILL FEED MOISTURE-RICH AIR INTO THE REGION THROUGH MOST OF THE WEEKEND... RESULTING IN A LENGTHY STRETCH OF WIDESPREAD LIGHT TO MODERATE RAINFALL. DRIER CONDITIONS WILL PREVAIL HEADING INTO LATE SUNDAY AND EARLY NEXT WEEK. && .NEAR TERM /THROUGH FRIDAY/... AS OF 8 PM...VERY IMPRESSIVE STREAM OF WATER VAPOR...FROM SOUTH OF CUBA NORTH ACROSS THE WESTERN CAROLINAS. BLENDED TOTAL PW PRODUCT INDICATES A PLUME OF GREATER THAN 2 INCHES BUILDING WEST ACROSS THE COASTAL PLAIN. NAM AND RAP INDICATES THAT LLVL WINDS WILL INCREASE FROM THE EAST...STRENGTHENING TO AROUND 30 KTS. THE LLVL FLOW WILL CREATE WIDESPREAD LIFT OVER A SFC RIDGE AND ALONG THE EAST FACING SLOPES. IN ADDITION...GFS40 SHOWS A FIELD OF Q-VECTOR CONVERGENCE DEVELOPING ACROSS THE CWA...ON THE NE SIDE OF A CLOSED MID LEVEL LOW. THERE IS NO QUESTION THAT RAINFALL WILL INCREASE ACROSS THE CWA DURING THE OVERNIGHT HOURS. I WILL UPDATE TO INCREASE POPS TO 100 PERCENT...OR VERY CLOSE TO IT. TEMPERATURES MAY REMAIN NEARLY STEADY THROUGH THE REST OF TONIGHT. AS OF 530 PM...LATEST SATELLITE LOOP SHOWS A BAND OF DEEP CONVECTION OFF THE CENTRAL SC SHORE...DRIFTING NORTHWARD. A BAND OF COLDER CLOUD TOPS HAS PIVOTED BACK TOWARD THE COAST...RESULTING IN WARMING CLOUD TEMPERATURES ACROSS THE MIDLANDS OF SC AND CENTRAL GA. BASED ON THE SATELLITE TRENDS...THE CURRENT BAND OF LIGHT RAINFALL MAY SLIDE TOWARD THE WEST...FOLLOWED BY CLUSTERS OF LIGHT RAIN HEADED INTO THIS EVENING. THE ENVIRONMENT BECOMES MORE DYNAMIC LATER THIS EVENING AND OVERNIGHT. NAM AND RAP FORECAST SOUNDINGS INDICATE A DEEP LAYER OF EAST LLVL FLOW ACROSS THE WESTERN CAROLINAS. PWS WILL INCREASE TO NEARLY 2 INCHES WITH THE WARM CLOUD LAYER DEEPENING TO AROUND 13 KFT. IN ADDITION...GFS40S SHOWS A FIELD OF Q-VECTOR CONVERGENCE DEVELOPING ACROSS THE CWA... ON THE NE SIDE OF A CLOSED MID LEVEL LOW. I WILL UPDATE THE FORECAST TO ADJUST POP TIMING AND INCREASE QPF ACROSS THE UPSLOPE AREAS. AT 230 PM EDT THURSDAY...AN UPPER LOW OVER THE SE AND AND ASSOCIATED SURFACE LOW OVER OFF THE GA COAST WILL CONTINUE TO SEND MOISTURE INLAND TOWARD THE BLUE RIDGE TONIGHT AND FRIDAY. THE COMBINATION OF DIFFLUENT FLOW ALOFT...INCREASING EASTERLY LOW LEVEL UPSLOPE FLOW...INCREASING EASTERLY ISENTROPIC UPGLIDE OVER A SURFACE RIDGE...AND MOISTURE WELL ABOVE NORMAL...WILL FAVOR THE DEVELOPMENT OF HEAVY PRECIPITATION ALONG THE EAST FACING BLUE RIDGE. ALTHOUGH MUCH OF THE AREA IS CURRENTLY IN DROUGHT...LOCALIZED FLOODING COULD OCCUR IN SMALLER STREAM BASIN AND HILLY TERRAIN. A FLASH FLOOD WATCH WILL BE NOT ISSUED OUR BLUE RIDGE AREA...AS IT APPEARS PRECIPITANT WILL GRADUALLY SPREAD NE FROM THE UPPER SAVANNAH RIVER VALLEY TO THE NC MOUNTAINS. TEMPERATURES WILL RUN BELOW NORMAL IN COOL NE SURFACE FLOW...ESPECIALLY MAXIMUMS UNDER CLOUD COVER. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... AS OF 255 PM THURSDAY...ALTHOUGH GUIDANCE CONTINUES TO SHOW WIDESPREAD RAIN AT THE START OF THE PERIOD THEN GRADUALLY DIMINISHING IN COVERAGE BY THE END OF THE PERIOD...THEY HAVE BACKED OFF ON AMOUNT OF QPF. MANY OF THE TRADITIONAL PARAMETERS NEEDED FOR FLOODING TYPE RAINFALL ARE NOT THERE. OPS MDLS SHOW PW VALUES ARE UP TO 190 PERCENT OF NORMAL...BUT THE ENSEMBLE GUIDANCE SHOWS 1 TO MAYBE 1.5 STANDARD DEVIATIONS ABOVE NORMAL. WHILE THERE IS SOME UPPER DIVERGENCE ASSOCIATED WITH THE UPPER JET MAX...1 STD DEVIATION ABOVE NORMAL...THIS DISSIPATES ON SAT AS THE JET MOVES OUT OF THE AREA. THE MAIN FORCING WILL COME FROM STRONG UPSLOPE FLOW WITH THE ENSEMBLE GUIDANCE SHOWING H85 ELY FLOW UP TO 4 STD DEVIATIONS ABOVE NORMAL. THERE WILL ALSO BE STRONG ISENTROPIC LIFT IN THE VERY MOIST LOW LEVELS. THE ENSEMBLE GUIDANCE CONTINUES TO SHOW A NORTHWARD SHIFT IN THE BEST H85 FLOW THRU THE PERIOD...ALTHOUGH THE SREF DOES KEEP IT OVER OUR PORTION OF THE BLUE RIDGE LONGER THAN THE GEFS. GIVEN THESE FACTORS...WPC HAS DROPPED THE QPF FCST ACROSS THE AREA. HAVE FOLLOWED THESE TRENDS AS WELL. THAT SAID...THIS STILL PUTS 1 TO 3 INCHES OF RAIN ACROSS AND NEAR THE NRN BLUE RIDGE...SO WILL HAVE TO KEEP AN EYE ON THE RAINFALL AMOUNTS. CANNOT RULE OUT FLOODING... BUT IT APPEARS TO NOT BE WIDESPREAD AND WARRANT A WATCH AT THIS TIME. HIGHEST POPS WILL BE ALONG AND NEAR THE BLUE RIDGE THRU THE PERIOD...WITH LOWER POP ACROSS THE SWRN CWFA. WITH A WEDGE PATTERN IN PLACE AND CONTINUED RAINFALL...EXPECT BREEZY AND COOL CONDITIONS EACH DAY. HIGHS WILL BE NEARLY 10 DEGREES BELOW NORMAL ON SAT THEN RISE A COUPLE OF DEGREES SUN. LOWS WILL BE ABOUT 5 DEGREES ABOVE NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AS OF 230PM THURSDAY...THE EXTENDED PERIOD BEGINS ON SUNDAY NIGHT WITH THE WEEKEND RAINFALL EVENT ON THE WANE AND DRIER CONDITIONS BUILDING IN ACROSS THE FORECAST AREA. WHILE FLOW ALOFT WILL BE SOUTHERLY THANKS TO A CUT-OFF 500MB LOW OVER SOUTH TEXAS AND AN ANTICYCLONE OVER THE WESTERN SARGASSO SEA...SURFACE HIGH PRESSURE AND A LACK OF NOTABLE SHORTWAVES IN THE FLOW ALOFT SHOULD KEEP THE AREA MOSTLY DRY THROUGH MIDDAY TUESDAY. THEREAFTER...THERE IS GENERAL AGREEMENT THAT A LONGWAVE TROUGH WILL MOVE ACROSS THE NORTHERN HALF OF THE U.S. AND CANADA AND AN ASSOCIATED SURFACE LOW PRESSURE SYSTEM AND ATTENDANT COLD FRONT WILL APPROACH OUR AREA ON WEDNESDAY. BOTH THE GFS AND THE ECMWF ARE NOT EXCITED ABOUT NOTABLE RAINFALL AS A RESULT OF THE FRONTAL PASSAGE...HOWEVER...THE GFS CONTINUES TO BE BULLISH ON A MODEST BUT WELL-DEFINED SURFACE LOW MOVING NORTHWARD OVER THE CENTRAL GULF AND APPROACHING THE LOUISIANA COAST BY TUESDAY AFTERNOON. THE ECMWF WEAKENS THE LOW TO AN OPEN TROUGH OVER THE NORTHERN GULF. BOTH MODELS DO NOT BRING THE FEATURE INLAND...HOWEVER THE GFS KEEPS THE SOUTHERN APPALACHIANS IN A MOISTURE-RICH ENVIRONMENT WITH A TROPICAL CONNECTION TO THE CARIBBEAN AND EJECTS ROUNDS OR BANDS OF CONVECTIVE PRECIP NORTH FROM THE GULF LOW ACROSS THE DEEP SOUTH AND INTO OUR AREA BEGINNING TUESDAY EVENING AND LASTING THROUGH WEDNESDAY. THE ECMWF PERSISTS WITH WEAK NORTHEASTERLY FLOW ACROSS MUCH OF THE SOUTHEAST HEADING INTO THURSDAY. AT THIS TIME THE FORECAST MAINTAINS SLIGHT CHANCE TO CHANCE POPS DURING THE MID-WEEK PERIOD GIVEN THE DECENT MOISTURE THAT REMAINS IN PLACE FOLLOWING THE EVENT ENDING ON SUNDAY...THE ANTICIPATED FRONTAL PASSAGE...AND THE PERSISTENCE OF BOTH MODELS OVER THE PAST FEW RUNS OF SUGGESTING SOME ACTIVITY IN THE GULF MOVING TOWARDS THE COAST. NEVERTHELESS...BOTH THE ECMWF AND GFS AGREE THAT A STRONG 1028MB SURFACE HIGH BUILDS IN ACROSS THE NORTHEAST U.S. ON THE CONFLUENT SIDE OF THE UPPER-LEVEL LONGWAVE TROUGH AND WEDGES DOWN ACROSS MUCH OF THE SOUTHEAST U.S.... SIGNIFICANTLY DRYING US OUT THROUGH THE END OF THE PERIOD ON FRIDAY MORNING. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... AT KCLT AND ELSEWHERE...VERY IMPRESSIVE STREAM OF WATER VAPOR...FROM SOUTH OF CUBA NORTH ACROSS THE WESTERN CAROLINAS. BLENDED TOTAL PW PRODUCT INDICATES A PLUME OF GREATER THAN 2 INCHES BUILDING WEST ACROSS THE COASTAL PLAIN. NAM AND RAP INDICATES THAT LLVL WINDS WILL INCREASE FROM THE EAST...STRENGTHENING TO AROUND 30 KTS. THE LLVL FLOW WILL CREATE WIDESPREAD LIFT OVER A SFC RIDGE AND ALONG THE EAST FACING SLOPES. THERE IS NO QUESTION THAT RAINFALL WILL INCREASE ACROSS THE CWA DURING THE OVERNIGHT HOURS. IN ADDITION...FORECAST SOUNDINGS CONTINUE TO INDICATE LOWERING CLOUD BASES TONIGHT. I WILL TIME RESTRICTIVE CEILINGS DEVELOPING THIS EVENING...REACHING IFR DURING THE PREDAWN HOURS. HEAVIER RAINFALL RATES SHOULD KEEP VIS IN THE LVFR TO MVFR RANGE THROUGH MOST OF THE 0Z TAF PERIOD. WINDS WILL REMAIN FROM THE NE...LIKELY GUSTY LATE TONIGHT THROUGH THE DAYLIGHT HOURS FRIDAY. OUTLOOK...DEEP MOISTURE AND WIDESPREAD LIFT WILL LIKELY RESULT IN RESTRICTIVE CEILINGS AND VISIBILITY PERIODICALLY THRU SATURDAY. IN ADDITION...RAINFALL WILL BE MODERATE TO HEAVY AT TIMES THROUGH SATURDAY. CONFIDENCE TABLE... 00-06Z 06-12Z 12-18Z 18-00Z KCLT HIGH 87% HIGH 97% HIGH 95% HIGH 98% KGSP HIGH 91% MED 79% HIGH 89% HIGH 94% KAVL HIGH 87% HIGH 82% MED 69% HIGH 89% KHKY HIGH 95% HIGH 99% HIGH 91% HIGH 97% KGMU HIGH 91% HIGH 94% HIGH 80% HIGH 100% KAND HIGH 91% HIGH 82% HIGH 88% HIGH 95% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...JMP NEAR TERM...NED SHORT TERM...RWH LONG TERM...JMP AVIATION...NED
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
718 PM CDT THU SEP 24 2015 .UPDATE... LATEST REGIONAL RADAR MOSAIC SHOWS LARGE AREA OF LIGHT RAIN CONTINUE TO SPREAD WESTWARD ACROSS THE APPALACHIANS INTO NORTHWEST GEORGIA AND EASTERN TENNESSEE. LATEST HRRR TIMES THIS LIGHT RAIN TO REACH THE PLATEAU COUNTIES AROUND 09Z OR SO...THEN SPREADING ACROSS MUCH OF THE REST OF THE CWA DURING THE DAY ON FRIDAY. CURRENT FORECAST HAS THIS ALL HANDLED AND NO CHANGES WERE MADE. AFTER ANOTHER MILD NIGHT TONIGHT...HIGHS TOMORROW WILL BE MUCH COOLER THAN SEEN RECENTLY DUE TO CLOUD COVER AND PRECIP...ESPECIALLY ON THE PLATEAU WHICH WILL LIKELY NOT MAKE IT OUT OF THE 60S. SHAMBURGER && .PREV DISCUSSION... /ISSUED 648 PM CDT THU SEP 24 2015/ UPDATE... FOR 00Z AVIATION. DISCUSSION... EASTERLY WAVE CURRENTLY LOCATED ACROSS NORTHERN FLORIDA THIS AFTERNOON. MOISTURE FETCH IS PRIMARILY ON THE EASTERN SIDE OF THE WAVE...AND THIS IS INDICATIVE OF THE LATEST RADAR TRENDS. SHOWER ACTIVITY COVERS MUCH OF SC INTO PORTIONS OF GA. THIS FEATURE IS EXPECTED TO TRACK NORTH NORTHWESTWARD OVER THE NEXT 24 TO 48 HOURS. MODELS ARE IN AGREEMENT WITH SPREADING THE DEEPER MOISTURE BACK UP ACROSS THE MIDDLE TN AREA...BEGINNING LATE TONIGHT AND CONTINUING INTO FRIDAY AND FRI NT. THE FEATURE IS EXPECTED TO WEAKEN BY SAT NT...AT WHICH TIME...THE DEEP MOISTURE SURGE WILL CUT OFF TO SOME DEGREE. AS FAR AS PRECIP PROBABILITIES GO...THE DEEP MOISTURE OVERRIDE CONCEPT APPEARS TO BE IN PLACE ACROSS OUR PLATEAU AREA FOR TOMORROW. WILL THEREFORE...TREND TOWARD GOING ABOVE GUIDANCE FOR POPS. WILL INSERT 70-80 POPS PLATEAU...AND TREND DOWNWARD AS YOU MOVE WEST. PRECIP AMOUNTS LOOK AS THOUGH THEY WILL BE ON THE LIGHT SIDE...PARTICULARLY WEST OF THE PLAT. CONVECTIVE PARAMETERS SHOW THAT LTG WILL BE HARD PRESSED TO DEVELOP. THE WIDESPREAD COVERAGE WILL TREND MORE TOWARD SCATTERED COVG AS WE MOVE INTO FRI NT AND SAT. FOR THE NEAR TERM TEMPS...LOW DIURNAL RANGES CAN BE EXPECTED GIVEN THE INCREASE IN CLOUDS AND MOISTURE. WILL DIFFER ONLY SLIGHTLY FROM THE MAV`S ADVICE. IN THE EXT FCST...WEAK TROUGHING IN THE UPPER LEVELS WILL REMAIN CAMPED OUT TO OUR NW. MODELS ELUDE TOWARD A TROPICAL WAVE DEVELOPING OVER THE GULF AND MOVING NORTHWARD. THE ASSOCIATED DEEP MOISTURE WILL ATTEMPT TO MAKE A RUN AT OUR AREA BY MID WEEK. THE SYSTEM...HOWEVER...WILL WEAKEN MARKEDLY AS IT MOVES OVER THE DEEP SOUTH. THIS WILL ACT TO CUT DOWN ON THE CONFIDENCE OF A TOPICAL INFUSION OF DEEPER MOISTURE THIS FAR NORTH. FOR THE FCST...WILL KEEP ONLY LOW TO MODERATELY HIGH POPS IN THE FCST. FOR THE EXT TEMPS...GIVEN THE TREND TOWARD A MORE TROPICAL TYPE OF PATTERN...LOOKS AS THOUGH HIGH TEMPS WILL BE NEAR SEASONAL LEVELS WHILE LOW TEMPS WILL RUN A GOOD 10 DEGREES OR SO ABOVE NORMAL. AVIATION... 00Z TAF DISCUSSION. VFR CONDITIONS SHOULD PERSIST FOR THE REMAINDER OF THE EVENING BEFORE LOWER CIGS AND RAIN CHANCES MOVE IN FROM THE EAST. KCSV WILL LIKELY BE IMPACTED FIRST AS THE UPPER LOW SLIDES EAST...AND KBNA AND KCKV SHOULD REMAIN VFR THROUGH THE OVERNIGHT AND MORNING HOURS. CIGS LOOK TO LOWER TO MVFR AROUND 10Z AT KCSV...AND AT KBNA AROUND 18Z. ISOLATED RAIN SHOWERS MAY BEGIN AFTER 06Z AT KCSV AS WELL. FOR NOW JUST HAVE MVFR VIS AFTER 10Z AT KCSV...AND MAY FALL TO IFR VIS BY MID MORNING. BARNWELL && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 63 75 62 75 / 20 50 50 50 CLARKSVILLE 62 79 61 74 / 0 20 40 50 CROSSVILLE 61 67 60 71 / 60 80 60 50 COLUMBIA 61 76 61 75 / 20 40 50 50 LAWRENCEBURG 62 76 62 75 / 20 40 40 50 WAVERLY 61 79 61 73 / 10 20 40 50 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 55
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
946 PM EDT THU SEP 24 2015 .SYNOPSIS... AN AREA OF LOW PRESSURE DEVELOPING ALONG THE SOUTHEAST ATLANTIC COAST WILL PUSH DEEP TROPICAL MOISTURE INTO THE APPALACHIANS AND CENTRAL MID ATLANTIC REGION. THIS WILL SPREAD RAINFALL ACROSS THE AREA FROM SOUTH TO NORTH OVERNIGHT...AND MARK THE BEGINNING OF WIDESPREAD RAINFALL THAT WILL PERSIST INTO THE WEEKEND. HIGH TEMPERATURES WILL REMAIN WELL BELOW NORMAL THROUGH SUNDAY WITH READINGS GENERALLY IN THE 60S...ALONG WITH A CHILLY NORTHEAST BREEZE. && .NEAR TERM /THROUGH FRIDAY/... AS OF 935 PM EDT THURSDAY... COVERAGE OF SHOWERS INCREASING OVER CENTRAL AND WESTERN NC...WITH POCKETS OF MODERATE RAIN. THE LATEST HRRR SHOWS THIS AREA OF PRECIP WELL...AND STARTS TO PROGRESS IT NWD INTO THE VIRGINIAS BETWEEN 10 PM AND 3 AM. THE FORECAST FOLLOWS THIS SCENARIO WHICH IS SOMEWHAT CLOSE TO THE EARLIER FORECAST. STILL LOOKS LIKE A GENEROUS QUARTER TO HALF INCH BY MORNING FROM THE NC/VA BORDER SWD...WITH LITTLE TO NO MEASURABLE OVER THE ALLEGHANYS. PWATS HAVE RISEN FROM .7 TO .89 HERE AT RNK PER SOUNDING FROM 8 AM TODAY TIL 8 PM...WHILE GSO HAS GONE FROM 0.74 TO 1.52 DURING THIS TIME. SITUATION WET FOR MORNING COMMUTE SO TRAVELER SHOULD WATCH FOR PONDING ON THE ROADS...MAINLY ACROSS INTERSTATE 81 SOUTHWEST OF CHRISTIANSBURG/BLACKSBURG...I-77 SOUTH OF WYTHEVILLE ALONG HIGHWAY 58 IN VIRGINIA...AND POINTS SOUTH. TEMPERATURES OVERNIGHT WITH MORE CLOUDS WILL DROP SOME ESPECIALLY ONCE RAIN HITS AND WET BULBS TO THE MID TO UPPER 50S. PREVIOUS AFTERNOON DISCUSSION... THE TROPICAL PLUME OF MOISTURE IS EVIDENT ON WV LOOPS THIS EVENING FROM THE SC/NC COAST NW INTO WRN NC. A GOOD AMOUNT OF RAIN IS ON THE WAY FOR THE APPALACHIANS AND CENTRAL MID ATLANTIC REGION. THE OVERALL SCENARIO ADVERTISED OVER THE PAST FEW DAYS IS STARTING TO UNFOLD AS DEVELOPING LOW PRESSURE ALONG THE SOUTHEAST ATLANTIC COAST IS THROWING DEEP TROPICAL MOISTURE IN OUR DIRECTION...CLEARLY EVIDENT IN WATER VAPOR IMAGERY. THIS WILL LEAD TO STEADILY THICKENING CLOUDS WITH PRECIPITATION SPREADING INTO THE REGION FROM THE SOUTH OVERNIGHT...MARKING THE START OF A PERIOD OF RAIN THAT WILL LAST INTO THE WEEKEND. WHILE THERE WILL LIKELY BE ENHANCEMENT OF PRECIPITATION ALONG THE BLUE RIDGE...WATER LEVELS ARE STILL RUNNING LOW FROM OUR RECENT DRY SPELL AND PRECIPITATION RATES DO NOT APPEAR THAT THEY WILL BE HIGH ENOUGH TO CAUSE A FLASH FLOOD CONCERN AT THIS TIME. WITH THIS IN MIND...THE AREA SEEMS WELL SITUATED TO ABSORB A LONG DURATION HEAVY RAINFALL EVENT WITHOUT CAUSING SIGNIFICANT PROBLEMS SO NO FLOOD/FLASH FLOOD WATCHES WILL BE ISSUED WITH THIS PACKAGE. AS ALWAYS...THE NEED FOR ANY FLASH/FLOOD WATCHES WILL CONTINUALLY BE MONITORED AND MAY BE ISSUED AT A LATER TIME IF CONDITIONS WARRANT. EXPECT THAT THE CLOUDS AND RAIN WILL KEEP TEMPERATURES QUITE COOL FOR TOMORROW AND WILL GO ON THE COOL SIDE OF GUIDANCE WITH MID/UPPER 60S EAST OF THE RIDGE AND LOW/MID 60S EAST. THE TIGHTENING PRESSURE GRADIENT BETWEEN THE WEDGE OF HIGH PRESSURE ALONG THE COASTAL PLAIN AND THE DEVELOPING LOW WILL MAKE FOR A STIFF NORTHEAST BREEZE OVERNIGHT AND THROUGH TOMORROW. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... AS OF 305 PM EDT THURSDAY... CLOSED UPPER LOW DRIFTS NORTH THROUGH THE TENNESSEE VALLEY THEN WEAKENS FRIDAY NIGHT AND SATURDAY. MODELS STILL ADVERTISING STRING EARLY FLOW OF ATLANTIC MOISTURE INTO THE REGION WITH 850 MB WINDS FROM THE EAST AT SPEEDS AS HIGH AS 45 KNOTS FRIDAY NIGHT INTO SUNDAY MORNING. MODELS SHOW A WELL DEFINED IN-SITU WEDGE WITH LITTLE TO NO INSTABILITY...EVEN ELEVATED ABOVE THE INVERSION. DEPTH OF WEDGE IS FORECAST TO BE 3000 TO 8000 FEET DEEP ACCORDING TO THE BUFKIT FROM THE GFS AND NAM. MUCH OF THE DEEP EASTERLY FLOW WILL OVERRUN THE COLD AIR IN THE WEDGE...WELL ABOVE ANY HEIGHTS THAT WOULD ADD TO UPSLOPE ENHANCEMENT. SO AXIS OF MAXIMUM PRECIPITATION MAY BE IN THE PIEDMONT...ON THE EASTERN EDGE OF THE COLD AIR DOME. BUT THERE WILL STILL BE A SECONDARY MAXIMUM ON THE EAST SLOPES OF THE BLUE RIDGE. WEDGE...CLOUDS AND PRECIPITATION WILL RESULT IN ONLY A SMALL RISE IN TEMPERATURES DURING THE DAY. HAVE LOWERED MAXIMUM TEMPERATURES FOR SATURDAY AND SUNDAY CLOSE TO ECMWF VALUES. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AS OF 305 PM EDT THURSDAY... SPREAD IN MODEL SOLUTIONS GROWS LARGER IN THIS TIME RANGE...ESPECIALLY FROM TUESDAY NIGHT THROUGH THURSDAY. SUNDAY NIGHT THROUGH TUESDAY MODELS SHOW A CLOSED UPPER LOW OVER TEXAS WITH RIDGING OVER THE WESTERN ATLANTIC. COASTAL SURFACE TROFFIING AND WEDGE OF HIGH PRESSURE OVER THE FORECAST AREA PERSISTS INTO MONDAY SO WILL MAINTAIN PROBABILITY OF PRECIPITATION DUE TO THE CONTINUED INFLOW OF MOISTURE OFF THE ATLANTIC. APPEARS BEST FORCING WILL BE CONFINED TO THE CLOSED LOW AND GULF COAST REGION AND MUCH FARTHER NORTH ALONG A COLD FRONT. ECMWF SHOWING DECENT 500 MB HEIGHT FALLS OVER NEW ENGLAND AND THE MID ATLANTIC REGION ON TUESDAY AND WEDNESDAY...WITH TROFFING CONTINUING TO DEVELOP OVER THE EASTERN UNITED STATES THROUGH THURSDAY. A WEAKENING COLD FRONT MOVES SOUTH ACROSS THE MID ATLANTIC REGION ON WEDNESDAY AND WEDNESDAY NIGHT FOLLOWED BY HIGH PRESSURE AND COOLER AIR ON THURSDAY. WPC WAS FAVORING A BLEND OF THE GFS/ECMWF. NOT MUCH MOISTURE LEFT ALONG THE FRONT BY WEDNESDAY SO WILL HAVE DAY 5 TO DAY 7 OF THE FORECAST DRY. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... AS OF 800 PM EDT THURSDAY... CURRENTLY VFR AT ALL TAF LOCATIONS. VIS SAT CONFIRMS HIGH CIRRUS STARTING TO OVERSPREAD THE REGION THIS EVENING. SCATTERED RAIN SHOWERS HAVE MOVED INTO THE NW NC MOUNTAINS WITH THE BULK OF THE PRECIP TO OUR SOUTH. RAIN AND LOWER CEILINGS WILL SLOWLY MOVE INTO THE AREA OVERNIGHT. PRECIP MENTIONED IN THE TAFS FIRST AT DANVILLE SHORTLY AFTER MIDNIGHT AND THEN REMAINING LOCATIONS BETWEEN 06-12Z AND LEWISBURG BY 14Z. EXPECT CEILINGS TO DROP TO MVFR AND EVENTUALLY IFR DURING THE DAY ON FRIDAY. LOW LEVEL WINDS WILL REMAIN OUT OF THE NORTHEAST...AND GUST 15-25KTS AT TIMES. EXTENDED AVIATION DISCUSSION... LOW PRESSURE WILL LINGER ALONG THE SOUTHEAST ATLANTIC COAST THIS WEEKEND. FORECAST MODELS AGREE THAT PERIODS OF RAIN WILL PERSIST THIS WEEKEND BUT DISAGREE SOMEWHAT ON INTENSITY. REGARDLESS OF THE AMOUNT OF RAIN...A STRONG EASTERLY FLOW WILL CONTINUE THROUGH SUNDAY AND SUB VFR CEILINGS/VISBYS SHOULD BE EXPECTED. THE WEDGE SHOULD WEAKEN ON MONDAY BRINGING IN DRIER AIR AND RETURN CONDITIONS TO VFR. HOWEVER ANOTHER STORM SYSTEM LOOKS TO ARRIVE MID WEEK BRINGING ANOTHER ROUND OF PRECIP AND SUB VFR CEILINGS/VISBYS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...MBS NEAR TERM...MBS/WP SHORT TERM...AMS LONG TERM...AMS AVIATION...CF/MBS
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1039 AM CDT WED SEP 23 2015 .UPDATE... NO CHANGE TO CURRENT FORECAST. && .AVIATION/18Z TAFS/... SOME MODELS ARE INDICATING FOG TONIGHT IN THE EAST COMING OFF THE LAKE...HOWEVER THINKING IT IS NOT LIKELY SINCE THE ATMOSPHERE LOOKS TO DRY. BROKEN MID LEVEL CLOUDS ARE EXPECTED TO CONTINUE OVER SOUTHWEST AND SOUTH-CENTRAL WI BUT WILL THEY WILL BE LIMITED TO SCATTERED OVER SOUTHEAST WI DUE TO DRY SOUTHEAST FLOW. && .MARINE... SOME MODELS ARE INDICATING FOG TONIGHT AND THURSDAY MORNING...HOWEVER THINKING IT IS NOT LIKELY SINCE ATMOSPHERE LOOKS TO DRY. MODIS IMAGERY SHOWING WATER TEMPS IN THE LOW 50S NEAR THE SHORE TO MID 50S NEAR THE OPEN WATER WHICH IS WITHIN 5 DEGREES OF FORECAST DEW POINTS...NOT SUPPORTIVE OF FOG DEVELOPMENT. IN ADDITION NORTHEAST WINDS ARE EXPECTED TO BE AROUND 5 KNOTS. && .PREV DISCUSSION... /ISSUED 321 AM CDT WED SEP 23 2015/ TODAY AND TONIGHT...FORECAST CONFIDENCE...HIGH. BOUNDARY LAYER WINDS OF 5 TO 10 KNOTS AND SLIGHTLY HIGHER LOW LEVEL MOISTURE WILL RESULT IN PATCHY EARLY MORNING FOG...ESPECIALLY IN LOW AREAS AND RIVER VALLEYS. OTRW...WEAK CONVERGENCE ALONG TRANSITIONING BOUNDARY/REMNANTS OF FRONT/ CONTRIBUTING TO SCT-BKN STRATOCU/ALTOCU OVER CENTRAL WI. THESE MID CLOUDS BRUSHING FAR NORTHWEST CORNER OF CWA. SC MAY EXPAND NEXT SEVERAL HOURS...BUT GENERAL DECREASING TREND OF 925-850RH EXPECTED TODAY FROM BOTH HRRR AND RAP. ENUF LINGERING LOW LEVEL RH TO ALLOW CU DEVELOPMENT LATER THIS MRNG...ESPECIALLY IN NORTH AND WEST. OTHER CONCERN IS UPSTREAM CIRRUS BLOWOFF FROM PLAINS CONVECTION. LIKELY THAT FIRST BATCH OF CIRRUS KNOCKING ON DOOR OF WEST CENTRAL WI WL LIKELY AFFECT PARTS OF SRN WI THIS MRNG BEFORE COMPLETELY THINNING. MORE UPSTREAM CONVECTION OVER WRN IA/MN EXPECTED LATER TODAY WHICH WILL GENERATE ANOTHER SWATH OF CIRRUS LIKELY TO AFFECT PARTS OF SRN WI LATE TODAY INTO THIS EVENING. POTENTIAL CLOUDS AND MORE SOUTHEAST SFC WIND FLOW WL KEEP TEMPS CLOSE TO OR SLIGHTLY BELOW LEVELS REACHED ON TUE. INCREASING SUBSIDENCE AND SOUTHEAST LOW LEVEL FLOW WL RESULT IN SLIGHTLY DRIER AIR ADVANCING INTO SRN WI FOR TONIGHT. HENCE HELD BACK ON FOG MENTION TONIGHT DESPITE MOST MESO MODELS SHOWING DENSE FOG DEVELOPING OVER ERN CWA AFT MIDNIGHT. BOUNDARY LAYER WINDS SLIGHTLY STRONGER TONIGHT...AND AIR MASS CONTINUES TO DRY WITH EACH WARM...MILD DRY DAY. ONE FLY IN OINTMENT IS LIGHT NORTHEAST FLOW POSSIBLY BRINGING IN MOISTER MARINE LAYER. THEREFORE CONFIDENCE LOWER ON FOG THREAT IN ERN CWA LATER TNGT. THURSDAY - CONFIDENCE...MEDIUM 500 MILLIBAR FLOW REGIME SHOWS A RATHER CHAOTIC VORT REGIME WITHIN THE OVERALL WEAK MID LEVEL FLOW...BUT ALL IN ALL THE DRY LOW LEVEL E-SE FLOW WITH SFC/850 ANTICYCLONE WILL MAINTAIN THE DRY LOOK. BUFKIT SOUNDINGS ARE ALSO SHOWING A VRY DRY AIRMASS. THE GFS SHOWS MORE MOISTURE AOA 15K FEET. NAM EVEN DRIER. FRIDAY THROUGH SUNDAY - CONFIDENCE...HIGH QUIET AND MILD PATTERN PERSISTS. SURFACE HIGH SHIFTS FURTHER AWAY SETTING UP MORE OF A SOUTHERLY RETURN FLOW. WARMEST DAY LIKELY TO BE SUNDAY AS 925 TEMPS GET CLOSE TO 20C. SUNDAY NIGHT THROUGH TUESDAY - CONFIDENCE...LOW THE 00Z ECMWF HAS COME IN SLOWER THAN THE PRIOR RUN...AND KEEPS SRN WI DRY FOR SUNDAY NIGHT. THE 00Z GEM LOOKS A LOT LIKE THE ECMWF WITH RESPECT TO FRONTAL SPEED BUT THE 00Z GFS IS STILL ABOUT A DAY BEHIND THE GEM/ECMWF SOLUTIONS. THE GFS SHOWS 925 TEMPS ON MONDAY/MONDAY EVENING INTO THE LOW/MID 20S CELSIUS WHILE THE ECMWF IS ALREADY SHOWING CAA THIS PERIOD. SO STILL SOME BIG DIFFERENCES TO GET RESOLVED WITH RESPECT TO FROPA TIMING...BUT SUPERBLEND CONTINUES TO SUPPORT THE SLOWER SOLUTION AND THE ECMWF IS INDEED TRENDING SLOWER BUT STILL A WIDE GAP REMAINS. GFS SOUNDINGS SHOW LITTLE IN THE WAY OF CAPE SO HAVE OPTED TO LEAVE OUT THUNDER MENTION AT THIS TIME. AVIATION/12Z TAFS/...SOME LIGHT FOG MAY AFFECT TAF SITES EARLY THIS MORNING. OTHERWISE...MAINLY A VFR PERIOD EXPECTED WITH MORE SE WINDS. SOME CONCERN OVER THREAT OF MORE SIGNIFICANT FOG IN ERN AREAS LATER TONIGHT AS DESCRIBED ABOVE. MARINE...PATCHY FOG IS POSSIBLE IN NORTHERN ZONE /LMZ643/ DUE TO COOLER LAKE WATER LOCATED IN THIS AREA AS SHOWN BY MODIS IMAGERY FROM AROUND 16Z/TUE. LIGHT AND VARIABLE SFC WNDS WL BECOME MORE E TO NE AND MAY ALLOW THE PATCHY FOG TO DEVELOP FOR A TIME THIS MORNING AND POSSIBLY AGAIN TONIGHT OVER MORE OF THE NEARSHORE AREA. MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. $$ TODAY/TONIGHT AND AVIATION/MARINE...MBK && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...MARQUARDT TODAY/TONIGHT AND AVIATION/MARINE...MBK THURSDAY THROUGH TUESDAY...COLLAR
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1038 AM CDT WED SEP 23 2015 .UPDATE... NO CHANGE TO CURRENT FORECAST. && .AVIATION/18Z TAFS/... SOME MODELS ARE INDICATING FOG TONIGHT IN THE EAST COMING OFF THE LAKE...HOWEVER THINKING IT IS NOT LIKELY SINCE THE ATMOSPHERE LOOKS TO DRY. BROKEN MID LEVEL CLOUDS ARE EXPECTED TO CONTINUE OVER SOUTHWEST AND SOUTH-CENTRAL WI BUT WILL THEY WILL BE LIMITED TO SCATTERED OVER SOUTHEAST WI DUE TO DRY SOUTHEAST FLOW. && .MARINE... SOME MODELS ARE INDICATING FOG TONIGHT AND THURSDAY MORNING...HOWEVER THINKING IT IS NOT LIKELY SINCE ATMOSPHERE LOOKS TO DRY. MODIS IMAGERY SHOWING WATER TEMPS IN THE LOW 50S NEAR THE SHORE TO MID 50S NEAR THE OPEN WATER WHICH IS WITHIN 5 DEGREES OF FORECAST DEW POINTS...NOT SUPPORTIVE OF FOG DEVELOPMENT. IN ADDITION NORTHEAST WINDS ARE EXPECTED TO BE AROUND 5 KNOTS. && .PREV DISCUSSION... /ISSUED / TODAY AND TONIGHT...FORECAST CONFIDENCE...HIGH. BOUNDARY LAYER WINDS OF 5 TO 10 KNOTS AND SLIGHTLY HIGHER LOW LEVEL MOISTURE WILL RESULT IN PATCHY EARLY MORNING FOG...ESPECIALLY IN LOW AREAS AND RIVER VALLEYS. OTRW...WEAK CONVERGENCE ALONG TRANSITIONING BOUNDARY/REMNANTS OF FRONT/ CONTRIBUTING TO SCT-BKN STRATOCU/ALTOCU OVER CENTRAL WI. THESE MID CLOUDS BRUSHING FAR NORTHWEST CORNER OF CWA. SC MAY EXPAND NEXT SEVERAL HOURS...BUT GENERAL DECREASING TREND OF 925-850RH EXPECTED TODAY FROM BOTH HRRR AND RAP. ENUF LINGERING LOW LEVEL RH TO ALLOW CU DEVELOPMENT LATER THIS MRNG...ESPECIALLY IN NORTH AND WEST. OTHER CONCERN IS UPSTREAM CIRRUS BLOWOFF FROM PLAINS CONVECTION. LIKELY THAT FIRST BATCH OF CIRRUS KNOCKING ON DOOR OF WEST CENTRAL WI WL LIKELY AFFECT PARTS OF SRN WI THIS MRNG BEFORE COMPLETELY THINNING. MORE UPSTREAM CONVECTION OVER WRN IA/MN EXPECTED LATER TODAY WHICH WILL GENERATE ANOTHER SWATH OF CIRRUS LIKELY TO AFFECT PARTS OF SRN WI LATE TODAY INTO THIS EVENING. POTENTIAL CLOUDS AND MORE SOUTHEAST SFC WIND FLOW WL KEEP TEMPS CLOSE TO OR SLIGHTLY BELOW LEVELS REACHED ON TUE. INCREASING SUBSIDENCE AND SOUTHEAST LOW LEVEL FLOW WL RESULT IN SLIGHTLY DRIER AIR ADVANCING INTO SRN WI FOR TONIGHT. HENCE HELD BACK ON FOG MENTION TONIGHT DESPITE MOST MESO MODELS SHOWING DENSE FOG DEVELOPING OVER ERN CWA AFT MIDNIGHT. BOUNDARY LAYER WINDS SLIGHTLY STRONGER TONIGHT...AND AIR MASS CONTINUES TO DRY WITH EACH WARM...MILD DRY DAY. ONE FLY IN OINTMENT IS LIGHT NORTHEAST FLOW POSSIBLY BRINGING IN MOISTER MARINE LAYER. THEREFORE CONFIDENCE LOWER ON FOG THREAT IN ERN CWA LATER TNGT. THURSDAY - CONFIDENCE...MEDIUM 500 MILLIBAR FLOW REGIME SHOWS A RATHER CHAOTIC VORT REGIME WITHIN THE OVERALL WEAK MID LEVEL FLOW...BUT ALL IN ALL THE DRY LOW LEVEL E-SE FLOW WITH SFC/850 ANTICYCLONE WILL MAINTAIN THE DRY LOOK. BUFKIT SOUNDINGS ARE ALSO SHOWING A VRY DRY AIRMASS. THE GFS SHOWS MORE MOISTURE AOA 15K FEET. NAM EVEN DRIER. FRIDAY THROUGH SUNDAY - CONFIDENCE...HIGH QUIET AND MILD PATTERN PERSISTS. SURFACE HIGH SHIFTS FURTHER AWAY SETTING UP MORE OF A SOUTHERLY RETURN FLOW. WARMEST DAY LIKELY TO BE SUNDAY AS 925 TEMPS GET CLOSE TO 20C. SUNDAY NIGHT THROUGH TUESDAY - CONFIDENCE...LOW THE 00Z ECMWF HAS COME IN SLOWER THAN THE PRIOR RUN...AND KEEPS SRN WI DRY FOR SUNDAY NIGHT. THE 00Z GEM LOOKS A LOT LIKE THE ECMWF WITH RESPECT TO FRONTAL SPEED BUT THE 00Z GFS IS STILL ABOUT A DAY BEHIND THE GEM/ECMWF SOLUTIONS. THE GFS SHOWS 925 TEMPS ON MONDAY/MONDAY EVENING INTO THE LOW/MID 20S CELSIUS WHILE THE ECMWF IS ALREADY SHOWING CAA THIS PERIOD. SO STILL SOME BIG DIFFERENCES TO GET RESOLVED WITH RESPECT TO FROPA TIMING...BUT SUPERBLEND CONTINUES TO SUPPORT THE SLOWER SOLUTION AND THE ECMWF IS INDEED TRENDING SLOWER BUT STILL A WIDE GAP REMAINS. GFS SOUNDINGS SHOW LITTLE IN THE WAY OF CAPE SO HAVE OPTED TO LEAVE OUT THUNDER MENTION AT THIS TIME. AVIATION/12Z TAFS/...SOME LIGHT FOG MAY AFFECT TAF SITES EARLY THIS MORNING. OTHERWISE...MAINLY A VFR PERIOD EXPECTED WITH MORE SE WINDS. SOME CONCERN OVER THREAT OF MORE SIGNIFICANT FOG IN ERN AREAS LATER TONIGHT AS DESCRIBED ABOVE. MARINE...PATCHY FOG IS POSSIBLE IN NORTHERN ZONE /LMZ643/ DUE TO COOLER LAKE WATER LOCATED IN THIS AREA AS SHOWN BY MODIS IMAGERY FROM AROUND 16Z/TUE. LIGHT AND VARIABLE SFC WNDS WL BECOME MORE E TO NE AND MAY ALLOW THE PATCHY FOG TO DEVELOP FOR A TIME THIS MORNING AND POSSIBLY AGAIN TONIGHT OVER MORE OF THE NEARSHORE AREA. MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. $$ TODAY/TONIGHT AND AVIATION/MARINE...MBK && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...MARQUARDT TODAY/TONIGHT AND AVIATION/MARINE...MBK THURSDAY THROUGH TUESDAY...COLLAR
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
321 AM CDT WED SEP 23 2015 .TODAY AND TONIGHT...FORECAST CONFIDENCE...HIGH. BOUNDARY LAYER WINDS OF 5 TO 10 KNOTS AND SLIGHTLY HIGHER LOW LEVEL MOISTURE WILL RESULT IN PATCHY EARLY MORNING FOG...ESPECIALLY IN LOW AREAS AND RIVER VALLEYS. OTRW...WEAK CONVERGENCE ALONG TRANSITIONING BOUNDARY/REMNANTS OF FRONT/ CONTRIBUTING TO SCT-BKN STRATOCU/ALTOCU OVER CENTRAL WI. THESE MID CLOUDS BRUSHING FAR NORTHWEST CORNER OF CWA. SC MAY EXPAND NEXT SEVERAL HOURS...BUT GENERAL DECREASING TREND OF 925-850RH EXPECTED TODAY FROM BOTH HRRR AND RAP. ENUF LINGERING LOW LEVEL RH TO ALLOW CU DEVELOPMENT LATER THIS MRNG...ESPECIALLY IN NORTH AND WEST. OTHER CONCERN IS UPSTREAM CIRRUS BLOWOFF FROM PLAINS CONVECTION. LIKELY THAT FIRST BATCH OF CIRRUS KNOCKING ON DOOR OF WEST CENTRAL WI WL LIKELY AFFECT PARTS OF SRN WI THIS MRNG BEFORE COMPLETELY THINNING. MORE UPSTREAM CONVECTION OVER WRN IA/MN EXPECTED LATER TODAY WHICH WILL GENERATE ANOTHER SWATH OF CIRRUS LIKELY TO AFFECT PARTS OF SRN WI LATE TODAY INTO THIS EVENING. POTENTIAL CLOUDS AND MORE SOUTHEAST SFC WIND FLOW WL KEEP TEMPS CLOSE TO OR SLIGHTLY BELOW LEVELS REACHED ON TUE. INCREASING SUBSIDENCE AND SOUTHEAST LOW LEVEL FLOW WL RESULT IN SLIGHTLY DRIER AIR ADVANCING INTO SRN WI FOR TONIGHT. HENCE HELD BACK ON FOG MENTION TONIGHT DESPITE MOST MESO MODELS SHOWING DENSE FOG DEVELOPING OVER ERN CWA AFT MIDNIGHT. BOUNDARY LAYER WINDS SLIGHTLY STRONGER TONIGHT...AND AIR MASS CONTINUES TO DRY WITH EACH WARM...MILD DRY DAY. ONE FLY IN OINTMENT IS LIGHT NORTHEAST FLOW POSSIBLY BRINGING IN MOISTER MARINE LAYER. THEREFORE CONFIDENCE LOWER ON FOG THREAT IN ERN CWA LATER TNGT. .THURSDAY - CONFIDENCE...MEDIUM 500 MILLIBAR FLOW REGIME SHOWS A RATHER CHAOTIC VORT REGIME WITHIN THE OVERALL WEAK MID LEVEL FLOW...BUT ALL IN ALL THE DRY LOW LEVEL E-SE FLOW WITH SFC/850 ANTICYCLONE WILL MAINTAIN THE DRY LOOK. BUFKIT SOUNDINGS ARE ALSO SHOWING A VRY DRY AIRMASS. THE GFS SHOWS MORE MOISTURE AOA 15K FEET. NAM EVEN DRIER. .FRIDAY THROUGH SUNDAY - CONFIDENCE...HIGH QUIET AND MILD PATTERN PERSISTS. SURFACE HIGH SHIFTS FURTHER AWAY SETTING UP MORE OF A SOUTHERLY RETURN FLOW. WARMEST DAY LIKELY TO BE SUNDAY AS 925 TEMPS GET CLOSE TO 20C. .SUNDAY NIGHT THROUGH TUESDAY - CONFIDENCE...LOW THE 00Z ECMWF HAS COME IN SLOWER THAN THE PRIOR RUN...AND KEEPS SRN WI DRY FOR SUNDAY NIGHT. THE 00Z GEM LOOKS A LOT LIKE THE ECMWF WITH RESPECT TO FRONTAL SPEED BUT THE 00Z GFS IS STILL ABOUT A DAY BEHIND THE GEM/ECMWF SOLUTIONS. THE GFS SHOWS 925 TEMPS ON MONDAY/MONDAY EVENING INTO THE LOW/MID 20S CELSIUS WHILE THE ECMWF IS ALREADY SHOWING CAA THIS PERIOD. SO STILL SOME BIG DIFFERENCES TO GET RESOLVED WITH RESPECT TO FROPA TIMING...BUT SUPERBLEND CONTINUES TO SUPPORT THE SLOWER SOLUTION AND THE ECMWF IS INDEED TRENDING SLOWER BUT STILL A WIDE GAP REMAINS. GFS SOUNDINGS SHOW LITTLE IN THE WAY OF CAPE SO HAVE OPTED TO LEAVE OUT THUNDER MENTION AT THIS TIME. && .AVIATION/12Z TAFS/...SOME LIGHT FOG MAY AFFECT TAF SITES EARLY THIS MORNING. OTHERWISE...MAINLY A VFR PERIOD EXPECTED WITH MORE SE WINDS. SOME CONCERN OVER THREAT OF MORE SIGNIFICANT FOG IN ERN AREAS LATER TONIGHT AS DESCRIBED ABOVE. && .MARINE...PATCHY FOG IS POSSIBLE IN NORTHERN ZONE /LMZ643/ DUE TO COOLER LAKE WATER LOCATED IN THIS AREA AS SHOWN BY MODIS IMAGERY FROM AROUND 16Z/TUE. LIGHT AND VARIABLE SFC WNDS WL BECOME MORE E TO NE AND MAY ALLOW THE PATCHY FOG TO DEVELOP FOR A TIME THIS MORNING AND POSSIBLY AGAIN TONIGHT OVER MORE OF THE NEARSHORE AREA. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ TODAY/TONIGHT AND AVIATION/MARINE...MBK THURSDAY THROUGH TUESDAY...COLLAR
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
913 PM MDT THU SEP 24 2015 .UPDATE... ISSUED AT 910 PM MDT THU SEP 24 2015 LATEST 11-3.9U SATELLITE IMAGERY SHOWING A WIDE BAND OF LOW CLOUDS INCHING WESTWARD FROM WESTERN NEBRASKA TOWARDS THE PANHANDLE. LATEST HRRR GUIDANCE SHOWING FOG COULD BE WIDESPREAD ACROSS THE PANHANDLE AFTER MIDNIGHT. WENT AHEAD AND EXPANDED FOG TO COVER MUCH OF THE PANHANDLE TO THE WYOMING STATE LINE. UPDATES HAVE BEEN SENT. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 200 PM MDT THU SEP 24 2015 DRY AND WARM WEATHER WILL HOLD OVER THE CWA THROUGH SATURDAY COMPLEMENTS OF AN UPPER RIDGE THAT WILL BE OVER THE CWA THROUGH MOST OF THE PERIOD. THE RIDGE WILL WEAKEN SOME LATER SATURDAY AS SHORTWAVE ENERGY MOVES ACROSS SOUTHERN CANADA BUT THATS ABOUT THE ONLY WEATHER FEATURE OF NOTE OVERALL. SOME MAINLY VALLEY FOG WILL BE POSSIBLE AGAIN LATER TONIGHT INTO FRIDAY MORNING OVER THE NEB PANHANDLE AS WEAK EASTERLY FLOW MAY ADVECT IN SUFFICIENT MOISTURE UNDER CLEAR SKIES. TEMPERATURES WILL REMAIN ABOVE SEASONAL NORMS BOTH DAYS. .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 200 PM MDT THU SEP 24 2015 12Z MEDIUM RANGE MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE RIDGE AXIS FROM THE UPPER MIDWEST TO DESERT SOUTHWEST SLOWLY DRIFTING SOUTH AS SHORTWAVE ENERGY TRACKS EAST FROM THE PACIFIC NORTHWEST ACROSS THE NORTHERN TIER OF THE CONUS THROUGH MONDAY. THE GFS SHOWS A VORT LOBE EXTENDING FROM IA WESTWARD ACROSS SOUTHERN WY MONDAY NIGHT THROUGH TUESDAY...PULLING A PACIFIC FRONT ACROSS THE CWA. THE ECMWF MAINTAINS A WEAK RIDGE ALOFT WITH A WEAKER SHORTWAVE FURTHER NORTH. BOTH MODELS PRODUCE WIDELY SCATTERED CONVECTION...MAINLY IN THE VICINITY OF THE MOUNTAINS AND NORTHEAST CWA. IT WILL BE BREEZY EACH AFTERNOON WEST OF THE LARAMIE RANGE...WITH LIGHTER WINDS ELSEWHERE. IT WILL BE QUITE WARM SUNDAY AND MONDAY WITH HIGHS IN THE 70S AND 80S...COOL 5 TO 10 DEGREES TUESDAY...FOLLOWED BY SLIGHT WARMING WEDNESDAY AND THURSDAY. LOWS WILL RANGE FROM THE 40S TO LOW 50S. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 431 PM MDT THU SEP 24 2015 IFR/LIFR CONDITIONS EXPECTED TO RETURN TONIGHT FOR SEVERAL NEBRASKA PANHANDLE AIRPORTS. HRRR GUIDANCE USED HEAVILY IN THE 00Z TAFS AS IT DID EXTREMELY WELL LAST NIGHT. LOWERING CONDITIONS EXPECTED TO BEGIN AT KAIA AROUND 04Z...THEN KCDR AND KSNY RIGHT AROUND 06Z. EXPECTED TO LAST THROUGH MID MORNING. VFR CONDITIONS EXPECTED ACROSS SOUTHEAST WYOMING. && .FIRE WEATHER... ISSUED AT 200 PM MDT THU SEP 24 2015 DRY AND WARM CONDITIONS ARE EXPECTED TO CONTINUE INTO EARLY NEXT WEEK. SOME ELEVATED CONCERNS IN THE AFTERNOONS OVER WESTERN SECTIONS WHERE WINDS SHOULD COME UP A BIT BUT NOT LOOKING TOO STRONG AT THIS TIME. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...GCC SHORT TERM...RE LONG TERM...MAJ AVIATION...GCC FIRE WEATHER...RE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
440 PM MDT WED SEP 23 2015 .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 230 PM MDT WED SEP 23 2015 AFTERNOON WATER VAPOR LOOP DEPICTED TWO UPPER LEVEL LOWS...ONE STALLED OVER THE NORTHEAST GULF COAST AND THE OTHER MOVING NORTHEAST INTO THE SOUTHERN DAKOTAS. THE LATTER SYSTEM WAS PRODUCING A LARGE AREA OF CONVECTIVE PRECIPITATION FROM THE UPPER MIDWEST TO THE SOUTHERN HIGH PLAINS. A PRONOUNCED UPPER RIDGE EXTENDED FROM WY INTO THE SOUTHERN GREAT BASIN. WRAPAROUND LOW CLOUDS EXITED THE WESTERN NE PANHANDLE. MODERATE CU FORMED OVER THE HIGHER TERRAIN OF SOUTHEAST WY. TEMPERATURES WARMED INTO THE 70S TO AROUND 80 THIS AFTERNOON. NORTHWESTERLY WINDS WERE BREEZY ALONG AND WEST OF THE LARAMIE RANGE. THE 12Z NUMERICAL MODELS ARE IN GOOD AGREEMENT PROGGING THE UPPER RIDGE TO EXPAND INTO THE NORTH AND CENTRAL GREAT PLAINS THROUGH THE END OF THE WEEK. A RIDGE OF HIGH PRESSURE AT THE SURFACE WILL ALSO DOMINATE THE FRONT RANGE AND HIGH PLAINS DURING THE SHORT TERM WITH DRY CONDITIONS AND ABOVE NORMAL TEMPERATURES. THE NAM...SREF AND HRRR INDICATE SOME LOW LEVEL MOISTURE IN THE BOUNDARY LAYER TONIGHT AND EARLY THURSDAY MORNING...SO HAVE INCLUDED PATCHY FOG EAST OF THE LARAMIE RANGE. THE PRESSURE GRADIENT WILL BE RELATIVELY WEAK WITH WINDS GENERALLY 8 TO 15 KT DURING THE DAY AND 4 TO 7 KT AT NIGHT. .LONG TERM...(SATURDAY THROUGH WEDNESDAY) ISSUED AT 230 PM MDT WED SEP 23 2015 WARM WEATHER EXPECTED ACROSS THE CWA THROUGH THE PERIOD IN A RATHER STAGNANT PATTERN. AN UPPER RIDGE EXTENDING NORTHEAST OVER THE AREA SATURDAY WILL GET SUPPRESSED SOUTHWARD A BIT SUNDAY AS SHORTWAVE ENERGY MOVES ACROSS SOUTHERN CANADA BUT WILL STILL BE THE MAIN WEATHER INFLUENCE FOR THE CWA. A WEAK COOL FRONT MAY SAG SOUTH ACROSS THE PLAINS SUNDAY NIGHT OR MONDAY BUT THE BULK OF COOLER AIR BEHIND IT APPEARS IT WILL REMAIN OVER THE NORTHERN PLAINS. A BIT OF UPSLOPE PCPN POSSIBLE BEHIND THE FRONT AS WELL MONDAY...OTHERWISE DRY WEATHER WILL CONTINUE. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 436 PM MDT WED SEP 23 2015 NORTHEAST LOW LEVEL WINDS AND MOIST LOW LEVEL ATMOSPHERE WILL GIVE US ANOTHER CHANCE AT LOW CLOUDS AND FOG TONIGHT...MAINLY ACROSS THE NEBRASKA PANHANDLE. BEST LOCATIONS LOOK TO BE KAIA AND KCDR WHERE LATEST HRRR GUIDANCE HAS THE LOW CLOUDS COMING IN AROUND 05Z AT KAIA AND SHORTLY THEREAFTER AT KCDR. DO NOT THINK KCYS WILL GO DOWN AS HARD AS THIS MORNING...BUT WILL HAVE TO MONITOR WESTWARD PROGRESSION OF LOW LEVEL MOISTURE THIS EVENING. && .FIRE WEATHER... ISSUED AT 200 PM MDT WED SEP 23 2015 NEAR CRITICAL FIRE WEATHER CONDITIONS WILL CONTINUE FOR AREAS WEST OF THE LARAMIE RANGE THIS AFTERNOON WITH WARM TEMPERATURES...BREEZY WEST TO NORTHWEST WINDS AND LOW HUMIDITIES. WARM TEMPERATURES AND LOW HUMIDITIES WILL SPREAD ACROSS MUCH OF SOUTHEAST WYOMING BOTH THURSDAY AND FRIDAY...HOWEVER WIND SPEEDS WILL REMAIN BELOW CRITICAL THRESHOLDS. ACROSS WESTERN NEBRASKA...MINIMUM HUMIDITIES WILL RANGE FROM 25 TO 35 PERCENT THURSDAY AND FRIDAY. HUMIDITY RECOVERIES WILL RANGE FROM POOR TO FAIR WEST OF THE LARAMIE RANGE...TO GOOD TO EXCELLENT TO THE EAST. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...MAJ LONG TERM...RE AVIATION...GCC FIRE WEATHER...MAJ
AREA FORECAST DISCUSSION
NWS DES MOINES IA
417 AM CDT FRI SEP 25 2015 .SHORT TERM /TODAY/... ISSUED AT 411 AM CDT FRI SEP 25 2015 THE TROPICAL STORM REMNANTS ARE SHIFTING SOUTH THIS MORNING WITH UPPER RIDGING TO THE WEST AND AND UPPER LOW TO THE SOUTHEAST. A FEW SHOWERS STILL REMAIN AS OF 3 AM OVER FAR WESTERN IOWA AND MAY HAVE VERY LIGHT PRECIPITATION CLIPPING THE DENISON TO ATLANTIC AREAS THROUGH 7 AM. DRIER AIR WILL SHIFT IN FROM THE EAST. THIS DRIER AIR WILL GENERALLY BE BELOW 600 MB OR 15 KFT. ABOVE THIS LAYER THERE IS EASTERLY FLOW FROM THE ATLANTIC MAKING ITS WAY TO THE MIDWEST AND THIS WILL KEEP MID LEVEL CLOUDS AROUND THROUGH MUCH OF THE DAY THOUGH SOME BREAKS ARE EXPECTED. HI RESOLUTION GUIDANCE IS TRYING TO SUGGEST LIGHT PRECIPITATION OVER THE FAR NORTHEAST AHEAD OF THE BIGGEST PUSH OF DRY AIR THIS AFTERNOON. GIVEN THE WEAK FORCING AND A INCREASINGLY DEEP DRY LAYER...THE POTENTIAL FOR MEASURABLE PRECIPITATION IS VERY LOW THOUGH POSSIBLE A FEW SPRINKLES COULD OCCUR. THERMAL PROFILES ARE SLIGHTLY COOLER THAN ON THURSDAY AND THIS WILL YIELD TEMPERATURES NEAR TO A BIT BELOW THURSDAYS HIGHS OVER THE SOUTHEAST HALF. READINGS WILL BE WARMER OVER THE NORTHWEST COMPARED TO THURSDAY WITH A LEAST A FEW PERIODS OF SUN EXPECTED. .LONG TERM /TONIGHT THROUGH THURSDAY/... ISSUED AT 411 AM CDT FRI SEP 25 2015 A QUIET WEEKEND WITH ABOVE NORMAL TEMPERATURES IS ON TAP FOR CENTRAL IOWA. THE NEXT BEST CHANCE FOR RAIN WILL BE TOWARDS THE MIDDLE OF NEXT WEEK. THIS WEEKEND... WITH THE EXCEPTION OF THE NAM...00Z FRI MODELS INITIALIZING WELL WITH BAND OF MID/UPPER LEVEL CLOUDS EXTENDING FROM IOWA INTO EASTERN SOUTH DAKOTA. THE NAM SEEMS TO BE UNDER-DOING CLOUD COVER. THESE CLOUDS WILL FOLLOW THE UPPER LOW DESCRIBED IN THE SHORT TERM DISCUSSION. AS THIS LOW CONTINUES TO SLOWLY PROPAGATE SOUTHWARD...CLOUDS WILL LIKELY BLANKET THE DMX CWA THROUGH 12Z SAT WHICH WILL HINDER DENSE FOG CHANCES. THUS...HAVE HELD FOG COVERAGE TO PATCHY...NOTING THAT FOG COVERAGE MAY NEED TO BE TRIMMED IN FRIDAY UPDATE. SUNSHINE EXPECTED SUNDAY AS SUBSIDENCE/DRY AIR ALOFT WINDS OUT. THERMAL PROFILE A DEGREE OR TWO COOLER ON SUNDAY THAN SATURDAY. BUT WITH THE INCREASED SUNSHINE...ENDED UP LEANING PERSISTENCE FROM SAT PLUS A DEGREE OR TWO. MONDAY... MODEL RUN-TO-RUN CONSISTENCY GOOD ENOUGH TO YIELD AT LEAST MDT CONFIDENCE IN FEATURING A BOUNDARY TO IMPACT IOWA. MODELS CONVERGING ON SOLN OF PLACING THIS BOUNDARY NEAR IA/MN/SD BORDER AT 12Z MON. AT 12Z MON...BOUNDARY APPEARS TO BE VERY MOISTURE-STARVED AS GULF CLOSED AND NO MOISTURE TRANSPORT MECHANISMS PRESENT. 700MB QG FRONTOGENETICAL FORCING BECOMES NON-EXISTENT. THUS HAVE LEFT POPS OUT AS THIS BOUNDARY PROPAGATES SOUTHEASTWARD THROUGH IOWA. TUESDAY INTO THURSDAY... THE AFOREMENTIONED BOUNDARY LOOKS TO LINGER ACROSS OUR CWA. WORTH NOTING THAT THE GULF DOES OPEN BACK UP SLIGHTLY DURING THIS TIME. ADDITIONALLY...MODELS DIALED IN ON PLACING A WELL-PRONOUNCED UPPER HIGH CENTERED SOMEWHERE NEAR BAJA CALIFORNIA. THIS HIGH IS PLACED IN SUCH A LOCATION THAT UPPER LEVEL MOISTURE WOULD BE TRANSPORTED UP FROM THE SW CONUS INTO IA...A FEATURE THAT HAS BEEN PRESENT IN SEVERAL SIGNIFICANT RAIN EVENTS THIS SUMMER...INCLUDING THE ONE FROM THE PAST FEW DAYS. WITH THE SLIGHT OPENING OF THE GULF...THE 00Z FRI GFS IS KICKING OUT PWATS IN THE 1.5 INCH RANGE...WHICH IS APPROACHING THE +1 TO +2 STD DEV RANGE. GOOD NEWS IS BEST MOISTURE TRANSPORT AND 25-30KT LLJ LOOKS TO BE CONFINEDTO KS/NE. THUS...LIKELIHOOD OF HEAVY RAIN EVENT APPEARS TO BE LOW. SUBSEQUENT MODEL RUNS WILL HAVE TO BE WATCHED CLOSELY...IF THIS SYNOPTIC SETUP SHIFTS EASTWARD INTO IA...THERE COULD BE SIGNIFICANT RAIN IN THE DMX CWA. AS FCST CONFIDENCE INCREASES...POPS WILL LIKELY END UP BEING INCREASED FOR THIS TIME PERIOD. && .AVIATION...25/06Z ISSUED AT 1141 PM CDT THU SEP 24 2015 OLD LOW CONTINUES TO TRANSLATE BACK TO THE SOUTHWEST OVERNIGHT TAKING LAST LOBE OF SHOWERS OVER NORTHERN IA INTO SOUTHERN MN AND SHRA OVER WESTERN IA SOUTH OF THE AREA AS THE ENTIRE SYSTEM WEAKENS. HRRR REDEVELOPS SOME -SHRA NEAR KMCW BETWEEN 12-17Z BUT FOR NOW HAVE LOW CONFIDENCE ON REDEVELOPMENT. OTHERWISE VFR CIGS EXPECTED WITH LIGHT ENE WINDS ACROSS THE REGION AS CLOUDS EVENTUALLY THIN BY 00Z SAT./REV && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DONAVON LONG TERM...KOTENBERG AVIATION...REV
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1141 PM CDT THU SEP 24 2015 .SHORT TERM /TONIGHT/... ISSUED AT 329 PM CDT THU SEP 24 2015 LOW PRESSURE ACROSS EASTERN NEBRASKA WILL CONTINUE TO INFLUENCE PRECIPITATION TRENDS THROUGH THE OVERNIGHT. MODELS SEEM TO HAVE A FAIR HANDLE ON TRACK OF LOW...ACCURATELY DEPICTING SHIFT NORTH TODAY BEFORE THE CURRENT SOUTHERN PUSH. AS LOW PULLS SOUTH...DRY AIR IS EXPECTED TO WORK IN AT LOW AND MID LEVELS WHICH WILL HELP TO KEEP PRECIPITATION TRENDS LIMITED TO THE EARLY PERIOD IN THE WEST. HAVE KEPT THUNDER MENTION ONLY THROUGH THE AFTERNOON GIVEN DECREASING INSTABILITY IN THE EVENING AND CURRENT LACK OF CONVECTION ACROSS THE REGION...WITH ANY ADDITIONAL RAINFALL EXPECTED TO BE GENERALLY SCATTERED. TEMPERATURES WARMED A BIT ABOVE GOING TODAY IN THE EAST WITH BREAKS IN CLOUDS. THEREFORE...WITH CLOUDS EXPECTED TO LINGER THROUGH THE OVERNIGHT...HAVE BUMPED OVERNIGHT LOWS A FEW DEGREES. .LONG TERM /FRIDAY THROUGH THURSDAY/... ISSUED AT 329 PM CDT THU SEP 24 2015 NOT MUCH CHANGE TO THE LONG TERM FORECAST. THE UPPER LOW WILL STILL BE MIGRATING SOUTH DUE TO THE FLOW OF THE BUILDING RIDGE TO THE WEST AND WILL SLIP SW IA. THERE MAY BE SOME LIGHT SHOWERS TO CONTEND WITH EARLY FRIDAY BUT OVERALL...FRIDAY WILL BE A MOSTLY CLOUDY AND DRY DAY. THE WEEKEND STILL LOOKS VERY NICE WITH A DRY AND WARM FORECAST CONTINUING INTO MONDAY. THE COLD FRONT SLATED FOR TUESDAY TIME FRAME HAS BETTER AGREEMENT BETWEEN THE MODELS NOW THOUGHT DIFFERENCES STILL REMAIN AS TO HOW FAR THE FRONT WILL GET ON TUESDAY. INSTABILITY AND SHEAR DO NOT LOOK OVERLY IMPRESSIVE SO WE MAY SEE MORE OF A SHOWERS WITH ISOLATED THUNDER SCENARIO AND BOTH MODELS ARE HINTING AT A MORE SPOTTY AND LIGHT QPF. FOR WEDNESDAY THE MODELS STILL DIVERGE WITH THE GFS DRY AND THE EURO STILL HINTING AT A SUBTLE SHORTWAVE DROPPING ACROSS THE NORTH AND EAST. I KEPT WITH PERSISTENCE SLIGHT CHANCE POPS AT THIS POINT BUT PULLED POPS OUT OF THE EAST ON THURSDAY WITH EVEN GREATER MODEL DISCREPANCY ON TIMING AND STRENGTH OF THE NEXT SHORTWAVE. && .AVIATION...25/06Z ISSUED AT 1141 PM CDT THU SEP 24 2015 OLD LOW CONTINUES TO TRANSLATE BACK TO THE SOUTHWEST OVERNIGHT TAKING LAST LOBE OF SHOWERS OVER NORTHERN IA INTO SOUTHERN MN AND SHRA OVER WESTERN IA SOUTH OF THE AREA AS THE ENTIRE SYSTEM WEAKENS. HRRR REDEVELOPS SOME -SHRA NEAR KMCW BETWEEN 12-17Z BUT FOR NOW HAVE LOW CONFIDENCE ON REDEVELOPMENT. OTHERWISE VFR CIGS EXPECTED WITH LIGHT ENE WINDS ACROSS THE REGION AS CLOUDS EVENTUALLY THIN BY 00Z SAT./REV && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...AWB LONG TERM...FAB AVIATION...REV
AREA FORECAST DISCUSSION
NWS JACKSON KY
136 AM EDT FRI SEP 25 2015 .UPDATE... ISSUED AT 136 AM EDT FRI SEP 25 2015 A FEW SHOWERS/SPRINKLES HAVE JUST MOVED INTO HARLAN COUNTY. STILL SOME PRETTY DRY AIR IN THE LOW LEVELS...AS DEWPOINTS REMAIN IN THE UPPER 40S IN SEVERAL AREAS. 00Z NAM/RAP BUFR SOUNDINGS DO NOT SHOW A REAL SATURATION OF THE LOW LEVELS FOR SEVERAL MORE HOURS. WITH THIS IN MIND...OPTED TO SLOW DOWN THE ADVANCEMENT OF THE BETTER POPS TO THE NORTHWEST. STILL A SOLID AREA OF PRECIPITATION BACK TO THE SOUTHEAST...AND EVENTUALLY THIS WILL WEAR DOWN THE DRY AIR IN THE LOW LEVELS...BUT IT MAY BE A SLOW PROCESS. REGARDLESS...RAINFALL TOTALS WILL REMAIN VERY LIGHT THROUGH THE MORNING HOURS. SOUNDINGS REALLY SATURATE THIS AFTERNOON ACROSS MOST OF EASTERN KENTUCKY...SO WILL GO CATEGORICAL AFTER DAYBREAK FOR ALL OF EASTERN KENTUCKY WITH THE RAIN CHANCES. BEST OMEGA REMAIN IN THE WARM PART OF THE CLOUD...SO EXPECT SHOWERS TO TAKE ON MORE OF A DRIZZLE...BUT SHOULD BE ENOUGH TO MEASURE EVERYWHERE THIS AFTERNOON. UPDATE ISSUED AT 1125 PM EDT THU SEP 24 2015 HOURLY TEMPERATURE AND DEWPOINT GRIDS HAVE BEEN UPDATED...BUT NO OTHER CHANGES WERE NEEDED ATTM. SHOWERS HAVE MEASURED AS FAR WEST AS THE INTERSTATE 81 CORRIDOR IN TN NEAR KTRI. GUIDANCE CONTINUES TO INDICATE THAT A BAND OF SHOWERS WILL SPREAD INTO THE AREA TOWARD DAWN. UPDATE ISSUED AT 850 PM EDT THU SEP 24 2015 A BROAD MID AND UPPER LEVEL LOW PRESSURE SYSTEM CONTINUES TO SPIN ACROSS THE SOUTHEASTERN CONUS. THIS IS BRINGING ATLANTIC MOISTURE WEST AND NORTHWEST ACROSS THE SOUTHEASTERN STATES AND INTO THE APPALACHIANS. RADAR RETURNS ARE GRADUALLY SPREADING ACROSS THE BLUE RIDGE AND INTO THE SMOKY MOUNTAINS AND NE TN MOUNTAINS. MOST OF THE MEASURABLE RAIN SO FAR HAS BEEN EAST OF THE BLUE RIDGE IN NC. MEANWHILE...A SFC AREA OF LOW PRESSURE WAS OFF THE SOUTHEAST US COAST WHILE AN AREA OF HIGH PRESSURE WAS CENTERED WELL NORTH OF THE AREA LEADING TO EASTERLY FLOW AT HIGHER ELEVATIONS NEAR THE VA BORDER AND NORTHEASTERLY FLOW IN MOST LOCATIONS. RECENT CONSSHORT AND HRRR GUIDANCE POINTS TOWARD A BIT SLOWER ARRIVAL OF SHOWERS INTO EASTERN KY AND RADAR TRENDS SUPPORT THIS. THE LEADING EDGE OF THE SHOWERS WILL LIKELY NOT BE MUCH MORE THAN SPRINKLES AS THE LOW LEVEL FLOW IS ACROSS THE APPALACHIANS AND HAS A DOWNSLOPE COMPONENT. HOWEVER...MOISTURE WILL INCREASE SUFFICIENTLY FOR SHOWERS WITH MEASURABLE RAIN TO SPREAD ACROSS SOUTHEAST KY TOWARD DAWN. HOURLY POPS HAVE BEEN ADJUSTED ACCORDINGLY WITH HOURLY DEWPOINTS AND TEMPERATURES FRESHENED UP BASED ON RECENT OBSERVATIONS. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 340 PM EDT THU SEP 24 2015 18Z SFC ANALYSIS SHOWS HIGH PRESSURE TO THE NORTH AND EAST OF KENTUCKY WHILE LOW PRESSURE IS FOUND OFF THE SOUTHEAST COAST. THIS LOW HAS BEEN RESPONSIBLE FOR SOME VERY LIMITED MID AND HIGH LEVEL CLOUDS SPREADING INTO KENTUCKY FROM THE SOUTHEAST. EXCEPT FOR PERHAPS THE FAR EAST...AMPLE SUNSHINE DOMINATED EAST KENTUCKY TODAY HELPING TO SEND TEMPERATURES UP INTO THE LOWER 80S FOR MOST PLACES. DEWPOINTS FELL INTO THE LOWER 50S DUE TO SOME DRY AIR MIX DOWN THIS AFTERNOON. WINDS...MEANWHILE...HAVE BEEN FROM THE NORTHEAST AT 5 TO 10 KTS TODAY. THE MODELS ARE IN GOOD AGREEMENT ALOFT...AS THEY HAVE BEEN FOR MUCH OF THIS WEEK IN THE SHORT TERM. THEY ALL DEPICT AN UPPER LOW...IN THE MIDST OF GENERAL HIGH HEIGHTS THROUGH MUCH OF THE NATION...SLOWLY DEVELOPING OVER THE SOUTHEAST. THIS LOW WILL CLOSE OFF AND DRIFT NORTHWEST WITH TIME...REACHING THE MID TENNESSEE VALLEY BY 12Z SATURDAY. PLENTY OF ENERGY WILL SPIN THROUGH THE HEART OF THIS LOW AS IT IMPACT OUR AREA LATER TONIGHT AND THROUGH THE REST OF THE PERIOD. THE ECMWF IS A BIT STRONGER WITH THIS LOW THAN THE OTHER MODELS WITH THE NAM12 IN THE MIDDLE OF THE CONSENSUS. GIVEN THE GENERAL MODEL AGREEMENT HAVE FAVORED THE HIGHER RESOLUTION NAM12 AND HRRR FOR WEATHER DETAILS. SENSIBLE WEATHER WILL FEATURE A DRY AND MOSTLY CLEAR EVENING ACROSS EAST KENTUCKY. CLOUDS WILL MOVE IN FROM THE EAST AND THICKEN DURING THE NIGHT WITH SHOWERS POTENTIALLY ARRIVING BEFORE DAWN IN THE FAR EAST. THIS AREA OF PRECIPITATION WILL THEN BUILD QUICKLY WEST THROUGH FRIDAY MORNING WITH MUCH OF THE CWA COVERED BY MIDDAY. THE EXCEPTION COULD BE FAR NORTHERN PARTS OF EAST KENTUCKY. SEVERAL ROUNDS OF SHOWERS ARE EXPECTED THROUGH THE AREA INTO SATURDAY WITH A DRIFT TO THE NORTH ANTICIPATED FOR THE DEEPER MOISTURE LATE IN THE PERIOD. POCKETS OF HEAVIER PCPN WILL BE POSSIBLE...BUT IN GENERAL BETWEEN A QUARTER AND A HALF OF AN INCH OF RAIN CAN BE EXPECTED FROM LATE TONIGHT THROUGH SATURDAY MORNING. TEMPERATURES WILL BE MORE UNIFORM WITH THE RAIN FRIDAY AND FRIDAY NIGHT...THOUGH THIS EVENING WE WILL STILL LIKELY SEE A RIDGE TO VALLEY SPLIT DEVELOP BEFORE THE THICKER AND LOWER CLOUDS MOVE IN FROM THE SOUTHEAST. AGAIN USED THE SHORTBLEND INITIALLY FOR TEMPERATURES AND DEWPOINTS...INTO THE FIRST PART OF THE DAY FRIDAY WITH THE SUPERBLEND USED FROM THAT POINT THROUGH THE REST OF THE PERIOD. DID MAKE SOME MINOR...TERRAIN BASED...ADJUSTMENTS TO THE TEMPERATURES THIS EVENING. AS FOR POPS...ENDED UP SIMILAR TO A BLEND OF THE MAV AND MET MOS THROUGH THE PERIOD. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 343 PM EDT THU SEP 24 2015 UPPER LEVEL LOW THAT HAS BEEN SPINNING NEAR THE FAR SOUTHEAST WILL SLOWLY RETROGRADE NORTHWEST THROUGH THE PERIOD. BEFORE EVENTUALLY BECOMING DEFUSE BY EARLY NEXT WEEK. HOWEVER MODELS BECOME MUCH MORE DIVERGENT THROUGH THE NEXT WEEK ESPECIALLY IN RELATION TO THE SURFACE. AT THE SURFACE THE PERIOD BEGINS WITH HIGH PRESSURE PARKED ACROSS NEW ENGLAND...MEAN WHILE A SURFACE TROUGH MOVES ACROSS THE REGION. BETTER CHANCES OF PRECIP WILL BE EARLY ON SAT WITH CHANCES WAINING THROUGH THE DAY. NOW STUCK CLOSER TO BLEND OVERALL THROUGH THE LONG TERM PERIOD FOR CONSISTENCY...BUT MAY BE A BIT OVERDONE WITH GFS SEEMING TO BE MORE EXAGGERATE PRECIP THROUGH THE PERIOD COMPARED WITH ECMWF/CANADIAN. PERHAPS THE BETTER DAY FOR PRECIP CHANCES WOULD BE AS WE MOVE INTO WED WITH SOME TROUGHING AND LOWER HEIGHTS. THEN TRENDING DRIER OVERALL AS WE MOVE INTO THURS. HAVE STUCK WITH RAIN SHOWERS AT THIS POINT GIVEN THE TIME OF YEAR AND MODEL SOUNDINGS SHOWING MEAGER INSTABILITY SIGNALS...HOWEVER BETTER CHANCES IF ANY OF THUNDER WOULD BE MID WEEK. OVERALL TEMPS THROUGH THE PERIOD WILL REMAIN NEARER NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 136 AM EDT FRI SEP 25 2015 MOISTURE CONTINUES TO STREAM INTO EASTERN KENTUCKY...CROSSING THE APPALACHIANS FROM THE ATLANTIC. THE LOWER LEVELS ARE LIKELY GOING TO TAKE SOME TIME TO SATURATE...AND HAVE SLOWED DOWN THE ONSET OF MVFR/IFR CEILINGS THIS AFTERNOON...UNTIL THIS EVENING. WE SHOULD SEE SOME FAIRLY LOW CIGS THIS EVENING DURING THE PERIOD OF BEST RAIN CHANCES. LIGHT RAIN WILL LIKELY BE SEEN THROUGH MUCH OF THE PERIOD...STARTING AROUND DAYBREAK. THE RAIN MAY HOLD OFF UNTIL THE AFTERNOON FARTHER NORTH TOWARDS KSYM. CIGS MAY IMPROVE LATE TONIGHT...AS SOUTHEAST FLOW STRENGTHENS HELPING TO DISSIPATE THE LOW LEVEL CLOUDS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KAS SHORT TERM...GREIF LONG TERM...DJ AVIATION...KAS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1209 AM CDT FRI SEP 25 2015 .SYNOPSIS... ISSUED AT 329 PM CDT THU SEP 24 2015 H5 ANALYSIS THIS MORNING HAD A POSITIVE TILTED RIDGE EXTENDING FROM SOUTHERN CALIFORNIA INTO THE NORTHERN ROCKIES. DOWNSTREAM OF THE RIDGE...A CLOSED LOW WAS NOTED OVER NERN NEBRASKA THIS MORNING...WITH A SECONDARY LOW OVER THE TEXAS PANHANDLE. BASED ON CURRENT SATELLITE IMAGERY...THE NORTHERN MOST UPPER LEVEL LOW WAS JUST WEST OF NORFOLK NEBRASKA. LIGHT RAIN SHOWERS IN ASSOCIATION WITH THE LOW...HAVE TRACKED FROM NORTH TO SOUTH ALONG HIGHWAY 281 FROM SPENCER TO BARTLETT THIS MORNING...AND HAVE SINCE DISSIPATED IN COVERAGE THIS AFTN. FURTHER WEST OF THE LOW....A BROAD SHIELD OF CLOUDINESS EXTENDED WEST TO THE NEBRASKA PANHANDLE WITH A MIXTURE OF LOW TO MID CLOUDS PRESENT. OVER THE PAST 1 TO 2 HRS...THE WESTERN EDGE OF THIS CLOUD COVER HAS BEGUN TO BURN OFF WITH CLEARING NOTED OVER PORTIONS OF THE EASTERN NEBRASKA PANHANDLE AND SWRN NEBRASKA. AT THE SURFACE...LOW PRESSURE WAS NOTED OVER NORFOLK NEBRASKA WITH A SURFACE TROUGH EXTENDING SSW INTO CENTRAL AND SWRN KS. WEST OF THE TROUGH NORTHWESTERLY WINDS WERE PRESENT FROM WEST OF THE LOW TO THE PANHANDLE. ACROSS THE PANHANDLE...WINDS WERE LIGHTER FROM THE NORTH OR WEST. TEMPERATURES AS OF 3 PM CDT...RANGED FROM 65 AT AINSWORTH TO 77 AT IMPERIAL. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 329 PM CDT THU SEP 24 2015 MAIN FORECAST CONCERNS OVER THE SHORT TERM...THROUGH FRIDAY AFTERNOON...ARE PRECIPITATION AND FOG. STRONG LOW PRESSURE CENTER CONTINUES TO SIT OVER CENTRAL AND EASTERN NEBRASKA...AND MAY RETROGRADE A LITTLE ON FRIDAY. FOR THE REMAINDER OF THURSDAY AFTERNOON AND EVENING...KEPT ISO/SCT POPS ACROSS NORTH CENTRAL NEBRASKA AS BANDS OF WEAK RAIN ROTATE SOUTH/SOUTHEAST ALONG THE BACKSIDE OF THE SURFACE LOW. LOWERED QPF AS MOST OF THE PRECIPITATION WAS BEING RECORDED AS DRIZZLE BY 20Z. THE TRICKY PART IS HOW FAR WEST THE THICK STRATUS WILL STRETCH THIS EVENING. THE PANHANDLE HAS STAYED CLEAR FOR MOST OF THE DAY AND BREAKS IN THE COVER HAVE COME AND GONE ALONG THE HIGHWAY 83 CORRIDOR. OVERNIGHT INTO FRIDAY MORNING...THINKING THE STRATUS WILL BEGIN TO EXPAND WESTWARD BY 25/06Z AS THE SURFACE LOW TREKS SOUTHWEST. NAM FORECAST SOUNDINGS SHOW A 5KFT SATURATED LAYER NEAR THE SURFACE IN THE EASTERN PORTIONS OF THE FORECAST AREA...ABOUT 2KFT THICK FROM KLBF TO KVTN...AND RELATIVELY SHALLOW IN THE PANHANDLE. THE NAM ALSO INDICATES SOME LIFT AND SATURATION AT THE 300K SURFACE IN THE EASTERN HALF OF THE FORECAST AREA...SO INTRODUCED DRIZZLE BEGINNING 09Z FRIDAY. FARTHER WEST...THE RUC AND GFS WERE AGREEING WITH SATURATION IN THE NEAR SURFACE LAYER. MENTIONED PATCHY FOG FOR THE ENTIRE FORECAST AREA...BUT THINKING THE WESTERN HALF WILL LIKELY EXPERIENCE MORE FOG WHILE EASTERN HALF HAS MORE DRIZZLE AND STRATUS. FOG WILL LIKELY BE MORE WIDESPREAD ALONG THE EDGE OF THE STRATUS...SO UPGRADED TO AREAS OF FOG BETWEEN THE PANHANDLE AND HIGHWAY 83. SURFACE WIND PROFILES WILL ALSO BE MORE FAVORABLE TOWARD FOG FARTHER WEST...AS SPEEDS STAY NEAR 10 MPH WHERE DRIZZLE IS MENTIONED. SOME FOG MAY BE LOCALLY DENSE...BUT AM NOT CONFIDENT ON COVERAGE DUE TO WIND. FRIDAY AFTERNOON...CONTINUED PATCHY DRIZZLE FOR THE EASTERN HALF OF THE FORECAST AREA AS SURFACE WINDS TURN EAST AND ADVECT IN MOIST AIR. FORECAST SOUNDINGS KEEP THE LOW LEVELS NEARLY SATURATED...SO ANY BIT OF LIFT COULD RESULT IN SOME LIGHT PRECIPITATION. TEMPERATURE WISE...LOWERED MIN TEMPS TONIGHT ACROSS THE PANHANDLE FOR MOSTLY CLEAR CONDITIONS AND LIGHT NORTH WINDS. LATEST GUIDANCE HAS LOWER TO MID 40S IN THE WESTERN SANDHILLS...BUT GENERALLY DID NOT GO THAT LOW. BUMPED UP A DEGREE ACROSS NORTH CENTRAL NEBRASKA DUE TO PERSISTENT STRATUS AND HIGHER DEW POINTS. CLOUD COVER WILL LIKELY LEAD TO A LARGE GRADIENT IN MAX TEMPS ACROSS THE FORECAST AREA FRIDAY. THE EASTERN PANHANDLE WILL LIKELY REMAIN UNDER FAIR SKIES...ALLOWING TEMPERATURES TO REACH THE UPPER 70S AND LOWER 80S. UNDER THE STRATUS IN THE EAST...LIMITED HIGHS TO THE LOWER 70S. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 329 PM CDT THU SEP 24 2015 FRIDAY NIGHT THROUGH SUNDAY...THE MAIN FORECAST CHALLENGES IN THE MID RANGE IS FOG POTENTIAL FRIDAY NIGHT...THEN TEMPERATURES. FOR FRIDAY EVENING...THE UPPER LEVEL LOW AND SURFACE LOW WILL DRIFT TO THE SOUTH SOUTHWEST INTO NORTHERN KANSAS. A WEAK SHORTWAVE WILL ROTATE ON THE NORTHWESTERN PERIPHERY OF THE LOW LATE FRIDAY AFTERNOON AND FRIDAY EVENING. ENOUGH WEAK FORCING IS PRESENT TO FACILITATE LOW POPS IN THESE AREAS FRIDAY EVENING. HOWEVER...THE MOIST LAYER IS FAIRLY SHALLOW FRIDAY EVENING AND FRIDAY NIGHT...SO THINKING HERE IS MORE OF A DRIZZLE SETUP FRIDAY EVENING...PARTICULARLY WITH DRYING ALOFT AND WEAK LIFT NOTED IN THE SATURATED LOW LAYER. AFTER LATE EVENING...THE THREAT FOR FOG WILL INCREASE OVERNIGHT AS LIGHT EASTERLY WINDS PERSIST ALONG WITH A VERY MOIST BOUNDARY LAYER. ATTM...THE MAIN AREA OF CONCERN FOR FOG IS WEST OF HIGHWAY 183. EAST OF THIS ROUTE...BUFKIT SOUNDINGS ARE MORE INDICATIVE OF STRATUS AS THE BOUNDARY LAYER IS SOMEWHAT DRIER. ON SATURDAY...THE REMNANTS OF THE LOW WILL FILL IN OVER SRN KS AS A POSITIVELY TILTED RIDGE BUILDS INTO NORTHERN NEBRASKA. SRLY WINDS WILL INCREASE IN THE AFTERNOON...PARTICULARLY IN THE WEST AS SURFACE LOW PRESSURE DEEPENS OVER NERN WYOMING. INCREASED SRLY WINDS...WILL ALLOW CLOUDINESS TO DISPERSE BY MIDDAY SAT ALLOWING HIGHS TO REACH THE UPPER 70S AND LOWER 80S. FOR SATURDAY NIGHT...LOW LEVEL MOISTURE WILL REMAIN PREVALENT ACROSS WESTERN AND NORTH CENTRAL NEBRASKA WITH OVERNIGHT DEW POINTS IN THE MID AND UPPER 50S. EVEN WITH DECENT BL MOISTURE PRESENT SAT NIGHT...AM NOT TOO CONCERNED ABOUT FOG ATTM WITH SRLY WINDS OF 10 TO 15 MPH EXPECTED OVERNIGHT. THE COMBINATION OF WIND AND LOW LEVEL MOISTURE...WILL LEAD TO A MILD NIGHT WITH LOWS IN THE 50S TO AROUND 60. ON SUNDAY...LOW PRESSURE WILL DROP SOUTHEAST INTO THE WESTERN PANHANDLE. SOUTHWESTERLY WINDS WILL INCREASE FURTHER ON SUNDAY AS MUCH WARMER H85 AIR PUSHES INTO THE PANHANDLE AND WESTERN HALF OF THE CWA. INCREASED HIGHS INTO THE UPPER 80S IN THE WEST...AND WOULDN/T BE SURPRISED IF WE SEE A 90+ TEMP IN THE EASTERN PANHANDLE OR FAR SW SUNDAY AFTERNOON GIVEN THE FCST H85 TEMPS OF 25 TO 29C. SUNDAY NIGHT THROUGH THURSDAY...MAINLY DRY CONDS WILL CONTINUE INTO MONDAY WITH HIGHS MAINLY IN THE 80S TO LOWER 90S. A PACIFIC COOL FRONT WILL PUSH INTO THE FORECAST AREA ON MONDAY NIGHT...STALLING OVER SRN NEBRASKA ON TUESDAY. MID LEVEL FRONTOGENESIS WILL INCREASE OVER CENTRAL AND NORTHERN NEBRASKA TUESDAY/TUESDAY NIGHT WITH THE THREAT FOR SHOWERS/TSRAS CONTINUED. BEYOND TUESDAY NIGHT...THE ECMWF AND GFS DIVERGE SIGNIFICANTLY IN THEIR SOLUTIONS. THE ECMWF BUILDS A RIDGE INTO THE CENTRAL CONUS WEDS/THURSDAY...WHICH WOULD LEAD TO DRY AND VERY WARM TEMPERATURES. THE 12Z GFS THIS MORNING HAS A LESS AMPLIFIED SOLUTION ACROSS THE CENTRAL CONUS WITH FAVORABLE JET DYNAMICS FOR PRECIPITATION WEDS THROUGH THURSDAY. INHERITED FCST HAD A MENTION OF PRECIPITATION WEDS-THUS. GIVEN THE MODEL DIFFERENCES...WILL LEAVE IN MENTION OF PCPN TO MAINTAIN A CONSISTENT FORECAST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1209 AM CDT FRI SEP 25 2015 STRATUS CONTINUES TO ROTATE SOUTHWARD THROUGH MUCH OF WESTERN AND NORTH CENTRAL NEBRASKA ON THE BACKSIDE OF A STORM SYSTEM. THE ATMOSPHERE WILL CONTINUE TO MOISTEN THE REST OF TONIGHT...AND EXPECT MVFR CEILINGS TO BECOME WIDESPREAD IFR BY SUNRISE. SOME DRYING IS EXPECTED IN THE LOWER ATMOSPHERE FRIDAY MORNING INTO THE AFTERNOON HOURS...AND EXPECT CEILINGS TO GRADUALLY LIFT AND IMPROVE THROUGH THE DAY FRIDAY. EXPECTING MOST AREAS TO BE VFR BY THE MIDDLE OF THE AFTERNOON FRIDAY. SOME PATCHY LIGHT DRIZZLE IS ALSO POSSIBLE THOUGH MID MORNING FRIDAY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CLB SHORT TERM...DS LONG TERM...CLB AVIATION...ROBERG
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1145 PM CDT THU SEP 24 2015 .UPDATE... ISSUED AT 855 PM CDT THU SEP 24 2015 UPDATED PRODUCTS A FEW TIMES TO INCREASE RAIN AMOUNTS. THINK THERE COULD BE SOME POCKETS OF UP TO TWO INCHES OF RAIN OVERNIGHT... MAINLY IN WESTERN IOWA. RECENT RAP MODEL OUTPUT SUGGESTS THAT POTENTIAL. CLOSED MID TROPOSPHERIC LOW SHOULD DROP SLOWLY SOUTHWARD THROUGH EASTERN NEBRASKA OVERNIGHT. THIS MAY FOCUS HEAVIEST AND LONGEST DURATION RAIN OVER WESTERN IOWA AND EXTREME EASTERN NEBRASKA NEAR THE MISSOURI RIVER. 00Z COAX SOUNDING WAS QUITE MOIST...WITH 1.74 PRECIPITABLE WATER AND DEEP WARM CLOUD DEPTH. SHOWERS AND SOME ISOLD THUNDERSTORMS HAVE BEEN EFFICIENT RAIN PRODUCERS SO FAR AND THIS MAY CONTINUE OVERNIGHT. ALREADY ISSUED ONE FLOOD ADVISORY PRODUCT. && .SHORT TERM...(TONIGHT THROUGH SUNDAY) ISSUED AT 318 PM CDT THU YEP 24 2015 VERTICALLY STACKED LOW CONTINUES TO SPIN ACROSS NORTHEAST NEBRASKA AT MID AFTERNOON...WITH NUMEROUS SHOWERS NOTED ACROSS THE NORTHERN HALF OF THE FORECAST AREA. INSTABILITY HAS REMAINED ON THE LOW SIDE TODAY...ALTHOUGH SAC HAS INDICATED ABOUT 500 J/KG OF ACROSS SOUTHEAST NEBRASKA. THE LOW WILL RESULT IN NUMEROUS SHOWERS THROUGH THE EVENING HOURS...AND COULD NOT RULE OUT AN ISOLATED RUMBLE OF THUNDER ACROSS SOUTHEAST NEBRASKA. THE LOW GRADUALLY BEGINS TO FILL OVERNIGHT AND DRIFT SOUTH...WITH SPOTTY SHOWERS LINGERING YET THROUGH FRIDAY AS THE LOW FINALLY BEGINS TO OPEN AND SHIFT SOUTHWEST OF THE REGION BY FRIDAY AFTERNOON/NIGHT. ONCE THE RAIN FINALLY ENDS...SHOULD SEE CLEARING SKIES FRIDAY NIGHT...WHICH COULD RESULT IN AREAS OF FOG EARLY SATURDAY MORNING. SOUTHEASTERLY SURFACE FLOW AS THE UPPER RIDGE BUILDS ALOFT WILL PREVAIL THROUGH THE REMAINDER OF THE WEEKEND WITH WARMING TEMPS BACK ABOVE NORMAL AND MOSTLY SUNNY SKIES. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 318 PM CDT THU YEP 24 2015 UPPER RIDGE REMAINS IN PLACE EARLY IN THE PERIOD WHICH SHOULD RESULT IN ANOTHER WARM AND MILD DAY MONDAY. THE NEXT WAVE MOVING ALONG THE US/CANADIAN BORDER SHOULD HELP PUSH A COOL FRONT INTO THE AREA MONDAY NIGHT INTO TUESDAY...WHICH BRINGS A SMALL CHANCE OF THUNDERSTORMS FOR THE NORTHERN HALF OF THE FORECAST AREA. BEYOND THEN...CONFIDENCE IS LOW IN THE DETAILS AS MODELS DIVERGE ON THE SOLUTIONS. ECMWF REMAINS DRY...BUT GFS INDICATES ANOTHER WEAK WAVE MOVING ONTO THE PLAINS WEDNESDAY NIGHT THROUGH THURSDAY. && .AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1145 PM CDT THU SEP 24 2015 IFR CEILINGS CONTINUE UNDER THE MID LEVEL LOW DROPPING SOUTH ACROSS EASTERN NEBRASKA...MAINLY AT KOFK. CONDITIONS SHOULD IMPROVE TOWARD MID MORNING FRIDAY THERE. FOR KOMA AND KLNK... PERIODS OF MVFR OR POSSIBLY EVEN IFR CONDITIONS ARE POSSIBLE INTO FRIDAY MORNING. PCPN COVERAGE SHOULD SLOWLY DECREASE. LOOK FOR VFR CONDITIONS BY FRIDAY AFTERNOON. FOG COULD DVLP FRIDAY EVENING...BUT LATER TAFS WILL ADDRESS THAT. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ UPDATE...MILLER SHORT TERM...DEWALD LONG TERM...DEWALD AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
131 AM EDT FRI SEP 25 2015 .SYNOPSIS... A LOW PRESSURE SYSTEM MOVING SLOWLY ONSHORE INTO COASTAL GEORGIA AND SOUTH CAROLINA TONIGHT...AND HIGH PRESSURE ANCHORED WELL TO THE NORTH...WILL BRING INCREASINGLY WET CONDITIONS AND SLIGHTLY BELOW NORMAL DAYTIME TEMPERATURES FOR THE NEXT FEW DAYS. THE LOW WILL LIFT NORTH LATE IN THE WEEKEND BRINGING A GRADUAL DRYING TREND SUNDAY INTO MONDAY...BUT LOW PRESSURE RISING OUT OF THE GULF OF MEXICO COULD BRING MORE RAIN IN THE UPCOMING WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 130 AM FRIDAY...RAIN IS ONGOING OVER THE CAPE FEAR REGION BUT MOST OF THE REST OF THE FORECAST AREA IS SEEING A LULL IN THE ACTIVITY AS A DRY SLOT MOVES IN. KEEPING CATEGORICAL POPS IN THE FORECAST THOUGH AS ALL INDICATIONS ARE THAT RAIN WILL RESUME LATER THIS MORNING. PREVIOUS DISCUSSION FOLLOWS: SYNOPTICALLY LITTLE HAS CHANGED OVER THE PAST FEW HOURS...HOWEVER ON THE MESOSCALE SIDE THERE HAS BEEN A RADICAL RECONFIGURATION OF PRECIPITATION ECHOES OBSERVED ON RADAR. A HUGE DRY SLOT HAS OPENED UP FROM MYRTLE BEACH SOUTHWARD FOR HUNDREDS OF MILES OVER THE OCEAN. THE 00Z RUN OF THE HRRR (NCEP OPERATIONAL RUN...NOT THE EXPERIMENTAL VERSION) SHOWS THIS QUITE WELL AND IS THE BASIS FOR THIS UPDATE. POPS WILL REMAIN HIGH...70-100 PERCENT...BUT RAINFALL AMOUNT FORECASTS HAVE BEEN TRIMMED BACK TO ACCOUNT FOR SPOTTIER SHOWERS OVER THE NEXT 4-6 HOURS. ONCE WE GET TO 5-6 AM A MORE SUSTAINED PERIOD OF SHOWERS MAY DEVELOP ACROSS THE CAPE FEAR REGION. DISCUSSION FROM 730 PM FOLLOWS... LOW PRESSURE IS CENTERED ABOUT 70 MILES EAST OF SAVANNAH ALONG A NEARLY STATIONARY FRONT LINING THE WESTERN WALL OF THE GULF STREAM. CLOSER TO CAPE FEAR THIS FRONT IS VERY NEAR THE LOCATION OF THE FRYING PAN SHOALS BUOY WHERE WIND DIRECTIONS HAVE OSCILLATED FROM SE TO NE OVER THE PAST FEW HOURS. ALTHOUGH THE LOW IS CENTERED OFFSHORE AT THE SURFACE...IT TILTS WESTWARD WITH HEIGHT AND AT 500 MB IS CENTERED OVER CENTRAL GEORGIA. DEEP SOUTH- SOUTHEASTERLY FLOW THROUGHOUT THE 850-500 MB LAYER IS BRINGING PRECIPITABLE WATER VALUES AROUND 2 INCHES UP TO THE CAROLINA COAST. FOR LATE SEPTEMBER THIS EXCEEDS THE 90TH PERCENTILE. AS THE UPPER LEVEL SYSTEM AND SURFACE LOW BOTH MOVE A LITTLE WESTWARD OVERNIGHT THE DEEP FLOW OF MOISTURE OFFSHORE SHOULD BECOME ORIENTED DIRECTLY ACROSS NE SOUTH CAROLINA AND SE NORTH CAROLINA. AS WINDS BECOME PERPENDICULAR TO THE FRONT...ISENTROPIC LIFT BECOMES IMPRESSIVE ALMOST REGARDLESS OF WHICH THETA LEVEL YOU LOOK AT GIVEN THE GREAT DEPTH OF MOISTURE. FORECAST POPS HAVE BEEN INCREASED TO A SOLID 100 PERCENT. IN TERMS OF PRECIP AMOUNTS...THROUGH 8 AM FRIDAY AREAL AVERAGE FORECASTS RANGE FROM ABOUT 0.60 INCHES ALONG THE SANTEE RIVER NEAR GEORGETOWN TO 1.50 INCHES ACROSS THE CAPE FEAR COAST. THERE WILL UNDOUBTEDLY BE CONVECTIVE ENHANCEMENT IN SPOTS WITH LOCALIZED 2-3 INCH TOTALS NOT OUT OF THE QUESTION. RAINFALL DEPARTURES OVER THE PAST THREE WEEKS ARE QUITE LARGE AND WE CAN PROBABLY TAKE 2-3 INCHES OF RAIN WITHOUT PROBLEM OUTSIDE OF TYPICAL URBAN/POOR DRAINAGE PROBLEM AREAS. ENOUGH MOISTURE HAS ADVECTED AROUND THE NORTH SIDE OF THE LOW THAT EVAPORATIONAL COOLING POTENTIAL IS DIMINISHING RAPIDLY. DEWPOINTS ARE NOW IN THE MID 60S EVEN IN DARLINGTON AND BENNETTSVILLE...WITH 70S AT THE NC COAST. AS THE RAIN BEGINS IN EARNEST ACROSS THE INTERIOR PEE DEE REGION OVER THE NEXT FEW HOURS LOOK FOR TEMPERATURES TO SETTLE INTO THE MID-UPPER 60S. IN FACT LOWS SHOULD REACH THE UPPER 60S MOST AREAS...AROUND 70 ON THE COAST. && .SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/... AS OF 3 PM THURSDAY...CHIEF WEATHER CAPTION THIS PERIOD...`RAIN`. DEEP TROPOSPHERIC ONSHORE WIND TRAJECTORIES ALREADY UNDERWAY AND POINTING LANDWARD UP THROUGH 30 THOUSAND FEET PER THE LATEST KLTX VAD WIND PROFILE DATA. THE MOST RECENT SATELLITE-DERIVED BLENDED PRECIPITABLE-WATER TRENDS SHOW VALUES OF 53MM-57MM/2.08-2.24 INCHES POISED JUST OFF THE BEACHES AND BLEEDING INTO THE SAVANNAH RIVER VALLEY SOUTH OF THE AREA. SURFACE CONVERGENCE AXIS OFFSHORE WHICH IS DEPICTED WELL IN AN EARLIER 1433Z ASCAT POLAR-ORBITER SWEEP EXTENDING SOUTH TO NORTH FROM OFFSHORE JAX FL TO E OF CAPE LOOKOUT...WILL GRADUALLY SHIFT TOWARD LAND INTO FRIDAY. THIS WILL AID IN CONVECTIVE INITIATION WHILE UPPER WINDS GUIDE CELLS AND DEBRIS RAINS ONSHORE. NO FLOOD WATCH IS PLANNED AT THIS TIME SINCE IT APPEARS BREAKS IN SIGNIFICANT RAIN-RATES WILL TRANSPIRE BETWEEN THE APPRECIABLE RAIN EPISODES...THE EPISODES NAMELY TONIGHT...AND AGAIN DURING THE DAY FRIDAY. SEVERAL IMPULSES WILL SUSTAIN RAIN CHANCES LATE FRIDAY AND SATURDAY BUT IT LOOKS LIKE LOCALLY...THE LOW-LEVEL CONVERGENCE WILL NOT BE AS STRONG AS TONIGHT AND FRIDAY...WHICH COULD STEM THE POTENTIAL ONSLAUGHT OF DEEP CONVECTIVE RAINS. MINIMUMS THIS PERIOD NEAR NORMAL MIDDLE 60S TO LOW 70S CLOSER TO THE SEA...WHEREAS MAXIMUMS WILL RUN 4-6 DEGREES F BELOW NORMAL IN THE MIDDLE AND UPPER 70S. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 3 PM THURSDAY...THE LONG TERM STILL LOOKS CONSIDERABLY CLOUDY AND UNSETTLED ALTHOUGH A WASHOUT IS NOT FORECAST. A VERY SLOW MOVING AND WEAK ATLANTIC SURFACE LOW SHOULD BE CENTERED NEAR CAPE LOOKOUT AT THE START OF THE PERIOD WITH ANY SIGNIFICANT RAINFALL N AND E OF THE CENTER. STRONG HIGH PRESSURE ACROSS NEW ENGLAND WILL WEDGE SOUTHWARD ACROSS THE CAROLINAS AT THE BEGINNING OF THE PERIOD. THE WEDGE IS EXPECTED TO BREAK DOWN WITH HIGH PRESSURE BECOMING CENTERED ACROSS THE CAROLINAS TUE AND WED. A 500 MB LOW WILL BE CUT OFF ACROSS THE SOUTHERN PLAINS WITH WEAK RIDGING DEVELOPING ACROSS THE CAROLINAS...AN EXTENSION OF THE WESTERN ATLANTIC RIDGE SUN THROUGH TUE. SURFACE LOW PRESSURE WILL BE MOVING N THROUGH THE GULF OF MEXICO AND MAY BE NEAR THE NORTHERN GULF COAST TUE-THU. A FRONTAL BOUNDARY WILL BE POSITIONED ACROSS THE OFFSHORE WATERS OF THE SOUTHEAST STATES. DEEP MOISTURE ASSOCIATED WITH GULF OF MEXICO SYSTEM SHOULD BE STREAMING NORTH MID AND LATE WEEK ALTHOUGH TOO EARLY TO SAY HOW WIDESPREAD THE RAINFALL WILL BE ACROSS THE EASTERN CAROLINAS. WILL SHOW LOWEST POPS EARLY IN THE WEEK AND THEN TREND SOMEWHAT HIGHER AS ISENTROPIC UPGLIDE SHOULD BEGIN TO INCREASE. FORECAST CONFIDENCE IS LOWER THAN NORMAL AND DEPENDENT ON EVOLUTION OF LOW PRESSURE IN GULF OF MEXICO. MOST OF THE PERIOD WILL BE DOMINATED BY A COOL NORTHERLY FLOW AND THIS ALONG WITH CONSIDERABLE CLOUD COVER WILL TEND TO SHRINK THE DIURNAL RANGE. HIGHS WILL GENERALLY BE BELOW NORMAL AND LOWS WILL BE ABOVE NORMAL FOR LATE SEPTEMBER. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 06Z...THE MAIN BAND OF HEAVIER PRECIP HAS WAVED TO THE NORTH BUT EXPECT SOME RAIN WITH EMBEDDED CONVECTION TO REFORM OVERNIGHT. LOOK FOR NEAR IFR CONDITIONS THROUGH MOST OF THE FORECAST PERIOD. SOME BRIEF BOUTS OF HEAVY PRECIP ARE POSSIBLE AT ALL TERMINALS THROUGH THE OVERNIGHT HOURS...HOWEVER EXPECT PREDOMINATELY LIGHT TO MODERATE RAIN UNTIL THE WINDS SHIFT TO THE EAST...PROBABLY NOT UNTIL AFTER DAYBREAK ON FRIDAY. THIS WILL BE THE BEST TIME FOR THE HEAVIER CONVECTION. WE PROBABLY WILL NOT SEE MUCH SOLAR INSOLATION...HOWEVER IF THE SUN DOES COME OUT THIS WILL ENHANCE CONVECTION AS IT WILL NOT TAKE MUCH. EXTENDED OUTLOOK...INTERMITTENT IFR CONDITIONS ARE POSSIBLE THROUGH SATURDAY. IMPROVING CONDITIONS SUNDAY AND MONDAY WITH DETERIORATING CONDITIONS AGAIN LATE TUESDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 130 AM FRIDAY...OBS SHOW SMALL CRAFT ADVISORY MARGINAL AT BEST AND AM KEEPING IT IN EFFECT THROUGH 4 AM ONLY FOR SOME WIND GUSTS OF AROUND 25 KTS. EXPECT WE WILL CANCEL ADVISORY...OR LET IT EXPIRE ON TIME AT 4 AM. PREVIOUS DISCUSSION FOLLOWS: AFTER CHATTING WITH NWS METEOROLOGISTS IN MOREHEAD CITY AND CHARLESTON WE HAVE AGREED TO EXPAND THE SMALL CRAFT ADVISORY TO INCLUDE ALL OF THE SOUTH CAROLINA COAST...AND EXTEND IT IN TIME UNTIL 4 AM FRIDAY MORNING. WIND GUSTS AT MYRTLE BEACH HAVE RECENTLY INCREASED TO 27 KNOTS AT SPRINGMAID PIER. THIS SURGE OF STRONGER WINDS WILL LIKELY PERSIST FOR ANOTHER 3-4 HOURS BEFORE DIMINISHING. GUSTS CONTINUE TO REACH 25 KNOTS AT WRIGHTSVILLE BEACH WITH WINDS NEARLY 30 KNOTS OUT AT THE BUOY 25 MILES OFFSHORE. AS WE SAW LAST NIGHT...THE CONFIGURATION OF THE PRESSURE GRADIENT IS SUPPORTING STRONGER WINDS UP AGAINST THE COAST RATHER THAN FARTHER OFFSHORE. DISCUSSION FROM 730 PM FOLLOWS... LOW PRESSURE IS CENTERED ABOUT 70 MILES EAST OF SAVANNAH ALONG A NEARLY STATIONARY FRONT LINING THE WESTERN WALL OF THE GULF STREAM. CLOSER TO CAPE FEAR THIS FRONT IS VERY NEAR THE LOCATION OF THE FRYING PAN SHOALS BUOY WHERE WIND DIRECTIONS HAVE OSCILLATED FROM SE TO NE OVER THE PAST FEW HOURS. BETWEEN THE FRONT AND THE COAST THE PRESSURE GRADIENT HAS BECOME PINCHED TIGHTLY AND WIND GUSTS ARE IN THE APPROACHING 30 KT BETWEEN CAPE FEAR AND CAPE LOOKOUT. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE SE NORTH CAROLINA COASTAL WATERS UNTIL MIDNIGHT. RECENTLY OBSERVED WIND GUSTS INCLUDE 27 KNOTS AT WRIGHTSVILLE BEACH...28 KNOTS AT THE NEARSHORE WRIGHTSVILLE BEACH CORMP BUOY. FOR THE SC COASTAL WATERS THE PRESSURE GRADIENT IS WEAKER AND WINDS ARE MORE IN THE 15-20 KT RANGE...HOWEVER IT REMAINS TO BE SEEN WHAT WIND SPEEDS WILL DO AS THE OFFSHORE FRONT APPROACHES OVERNIGHT. SEAS ARE CURRENTLY AS HIGH AS 5.2 FEET AT THE HARBOR BUOY SOUTH OF SOUTHPORT...AND ARE STILL 6.6 FEET AT FRYING PAN. THESE WAVE HEIGHTS SHOULD PEAK IN THE NEXT COUPLE OF HOURS WITH WAVES DIMINISHING BELOW 6 FEET BY MIDNIGHT. SHORT TERM/ FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 PM THURSDAY...ALTHOUGH NOT IDEAL AND MODERATELY BUMPY AT TIMES...NO ADVISORIES ARE PLANNED FRIDAY AND SATURDAY. SEAS ARE EXPECTED TO HOLD IN A 3-5 FOOT RANGE AND WINDS AROUND 15 KT. AN EXERCISE CAUTION STATEMENT MAY BE NEEDED SATURDAY AFTERNOON AND NIGHT AS SLIGHT STRENGTHENING OF HIGH PRESSURE TO THE NORTH INCREASES NE WINDS IN THE 15-20 KT RANGE. ISOLATED TSTMS CAN BE EXPECTED ON THE WATERS BOTH DAYS AND MARINERS SHOULD CHECK RADAR TRENDS BEFORE HEADING OUT. DOMINANT WAVE PERIODS WILL BE MIXED BETWEEN LONGER PERIOD ESE WAVES 2-3 FEET EVERY 10-11 SECONDS AND E WAVES 2-3 FEET EVERY 7-8 SECONDS...BOTH THESE WAVE GROUPS TO CO- MINGLE WITH A MODERATE NE CHOP. LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 3 PM THURSDAY...A MUCH MORE RELAXED PRESSURE GRADIENT...AS COMPARED TO RECENT DAYS...SHOULD BE IN PLACE SUNDAY AS WEAK LOW PRESSURE WILL BE MOVING PROGRESSIVELY N OF THE WATERS. THE WEDGE WILL BUILD STRONGLY SOUTH-SOUTHWEST WITH ITS ASSOCIATED TIGHTER PRESSURE GRADIENT REMAINING LARGELY W OF THE WATERS. HIGHEST WIND SPEEDS...UP TO 10 TO 15 KT SUN...SHOULD BE 10 KT OR LESS FOR THE REMAINDER OF THE FORECAST PERIOD. A NE OR ENE WIND DIRECTION WILL DOMINATE. SEAS WILL BE MAINLY 2 TO 3 FT ALTHOUGH SPOTTY 4 FT SEAS ACROSS THE OUTERMOST NORTHERN WATERS ARE POSSIBLE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR AMZ250-252-254-256. && $$ SYNOPSIS...MJC NEAR TERM...REK/TRA SHORT TERM...MJC LONG TERM...RJD AVIATION...DL MARINE...MJC/REK/RJD/TRA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
254 AM CDT FRI SEP 25 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 243 AM CDT FRI SEP 25 2015 CURRENTLY...HIGH PRESSURE WAS CENTERED OVER HUDSON BAY...WITH A TROUGH OF LOW PRESSURE ALONG THE LEE OF THE ROCKIES. ANOTHER SURFACE LOW WAS OVER EASTERN NEBRASKA. LOW LEVEL MOISTURE MAINLY ASSOCIATED WITH THE LOW OVER NEBRASKA HAD SPREAD NORTHWARD INTO THE NORTHERN PLAINS. LOW CLOUDS AND FOG WAS COMMON FROM WISCONSIN AND MINNESOTA INTO THE EASTERN DAKOTAS AND SOUTHERN MANITOBA. THE LATEST ITERATIONS OF THE SHORT TERM HRRR MODEL CONTINUE TO INDICATE LOW CLOUDS AND FOG EXPANDING ACROSS CENTRAL AND EASTERN NORTH DAKOTA...MAINLY EAST OF THE MISSOURI RIVER IN SOUTH CENTRAL NORTH DAKOTA AND EAST OF MINOT/BOTTINEAU IN THE NORTH CENTRAL. ROLLA AND JAMESTOWN STATIONS HAVE REPORTED 1/4 MILE VISIBILITY...AND EXPECT THOSE CONDITIONS TO EXPAND WESTWARD. THUS WILL ISSUE A DENSE FOG ADVISORY ALONG AND EAST OF A LINE FROM BOTTINEAU TO BISMARCK TO THE LINTON AND STRASBURG AREAS. THIS INCLUDES THE TURTLE MOUNTAINS AND THE JAMES RIVER VALLEY. THE HRRR INDICATES THAT VISIBILITIES SHOULD IMPROVE QUICKLY AROUND 10AM-11AM...SO WILL HAVE THE ADVISORY IN EFFECT UNTIL 11 AM CDT. SOUTHERLY WINDS SHOULD INCREASE DURING THE LATE MORNING AND HELP MIX THE SURFACE WITH THE BOUNDARY LAYER. EXPECT IMPROVING CONDITIONS THIS AFTERNOON WITH PARTLY TO MOSTLY SUNNY SKIES AND HIGHS IN THE MID-UPPER 70S CENTRAL TO LOWER 80S WEST. SOUTHERLY WINDS REMAIN TONIGHT AHEAD OF AN APPROACHING SURFACE TROUGH...AND MODELS HINT AT RETURN OF LOW CLOUDS AND POSSIBLE FOG TO THE AREA. FOR NOW HAVE INCREASED THE FORECAST SKY COVER A BIT...AND WILL SEE HOW THE NEXT SET OF MODELS HANDLES THE LOW LEVEL MOISTURE FIELD. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 243 AM CDT FRI SEP 25 2015 A WARM UP INTO SATURDAY FOLLOWED BY A COOLING TREND EARLY NEXT WEEK HIGHLIGHTS THE EXTENDED FORECAST. THE 24/12 UTC NAEFS PERCENTILES DEPICT 850MB TEMPERATURES IN THE 99TH TO NEAR MAXIMUM PERCENTILES ACROSS SOUTHEAST MONTANA INTO SOUTHWEST NORTH DAKOTA SATURDAY AFTERNOON AHEAD OF A STRONG COLD FRONT FORECAST TO OVERTAKE THE AREA SATURDAY NIGHT INTO SUNDAY. THUS...INCREASED HIGHS INTO THE LOWER 90S WEST OF THE MISSOURI RIVER FOR SATURDAY...WHICH IS ABOVE THE 00 UTC GUIDANCE CONSENSUS. THEREAFTER...TEMPERATURES DECLINE AS THE SATURDAY UPPER LEVEL RIDGE BREAKS DOWN AND COOL HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE REGION MONDAY INTO TUESDAY. WIDESPREAD HIGHS IN THE 60S...AND POSSIBLY THE 50S ARE EXPECTED. MORNING FROST WILL BE POSSIBLE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1245 AM CDT FRI SEP 25 2015 AT MIDNIGHT CDT...FOG WAS RE-DEVELOPING OVER MUCH OF EASTERN NORTH DAKOTA AS WELL AS ACROSS THE FAR NORTHERN PART OF THE STATE. VSBY AT KJMS WAS VARYING FROM 1/2SM TO 2SM. ROLLA WAS VARYING FROM 1/4SM TO 3SM WITH OVC002. FOG SHOULD CONTINUE TO DEVELOP AND EXPAND INTO CENTRAL NORTH DAKOTA...BRINGING IFR/LIFR CIGS AND VSBYS ACROSS CENTRAL NORTH DAKOTA...AND POSSIBLY PORTIONS OF THE WEST. WITH AN INCREASING SOUTHERLY FLOW FROM WEST TO EAST...THINK CONDITIONS IMPROVE FIRST IN THE WEST AND OVER HIGHER TERRAIN. CONDITIONS SHOULD IMPROVE OVER THE CENTRAL BY MID-MORNING FRIDAY. VFR CONDITIONS EXPECTED LATE MORNING THROUGH THE EARLY EVENING. THERE IS A HINT OF RETURNING FOG/LOW CLOUDS AFTER SUNSET FRIDAY EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 11 AM CDT THIS MORNING FOR NDZ004-005- 012-013-022-023-025-035>037-046>048-050-051. && $$ SHORT TERM...JV LONG TERM...AYD AVIATION...JV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1244 AM CDT FRI SEP 25 2015 .UPDATE... ISSUED AT 1245 AM CDT FRI SEP 25 2015 MAIN CONCERN THIS UPDATE IS DEVELOPMENT AND SPREAD OF FOG...AND HOW DENSE IT WILL BECOME WITH TIME OVERNIGHT. LATEST HRRR INDICATES LARGEST AREA OF FOG OVER THE SOUTHEAST QUARTER OF THE STATE BY AROUND 2 AM...AND ENCOMPASSING MUCH OF CENTRAL AND EASTERN NORTH DAKOTA BEFORE SUNRISE. THE LATEST HRRR RUN INDICATES THE VISIBILITIES WOULD BE VERY LOW - 1/4 MILE OR LESS - WHICH WOULD RESULT IN A DENSE FOG ADVISORY. THINKING A DENSE FOG ADVISORY WILL BE NEEDED SOON...AND WILL BE COORDINATING WITH SURROUNDING OFFICES. FOR NOW WILL ISSUE A STATEMENT FOR THE TURTLE MOUNTAINS THROUGH THE JAMES VALLEY REGARDING AREAS OF FOG WITH PATCHY DENSE FOG. OTHERWISE TEMPERATURES AND WIND FORECAST APPEARS TO BE IN GOOD SHAPE. UPDATE ISSUED AT 941 PM CDT THU SEP 24 2015 LATEST HRRR IS NOT AS AGGRESSIVE IN SPREADING LOW STRATUS INTO WESTERN NORTH DAKOTA. IT DOES BRING SOME LOW STRATUS INTO THE SOUTHWEST AROUND 08-10 UTC THEN DISSIPATES. THINK THE INCREASING SOUTHERLY FLOW AND INCREASING HIGH CLOUDS IS ATTRIBUTING TO THE DISSIPATING STRATUS HERE. STRATUS/FOG DOES EXPAND ACROSS CENTRAL NORTH DAKOTA AFTER MIDNIGHT TO INCLUDE JAMESTOWN BISMARCK AND POSSIBLY MINOT...WITH MAX COVERAGE AROUND 13 UTC. WILL UPDATE CLOUD COVER USING THE LATEST HRRR AS GUIDANCE. OTHERWISE NO SIGNIFICANT UPDATES NEEDED. UPDATE ISSUED AT 621 PM CDT THU SEP 24 2015 LATEST SURFACE ANALYSIS SHOWS SURFACE LOW PRESSURE OVER NORTHEAST NEBRASKA WITH A SURFACE RIDGE EXTENDING EAST TO WEST ALONG THE INTERNATIONAL BORDER. THIS WILL KEEP A SOUTH TO SOUTHEAST OVER THE FORECAST AREA TONIGHT. WITH ABUNDANT LOW LEVEL MOISTURE OVER THE AREA EXPECT AREAS OF FOG TO DEVELOP ONCE AGAIN TONIGHT. A LIMITING FACTOR MAY BE A SHORTWAVE TRACKING THROUGH WESTERN CANADA...OVER THE UPPER LEVEL RIDGE. THIS WILL BRING INCREASING LOW LEVEL SOUTHERLY FLOW TO ESPECIALLY WESTERN NORTH DAKOTA LATE TONIGHT. THERE MAY BE ENOUGH TURBULENCE IN THE LOWER LEVELS TO INHIBIT WIDESPREAD FOG DEVELOPMENT IN THE WEST. FOR NOW WILL KEEP WITH THE GOING FORECAST OF AREAS OF FOG ACROSS WESTERN AND CENTRAL NORTH DAKOTA. WILL HIT LOWER CIGS/VISIBILITIES AT KBIS AND KJMS IN THE TAF FORECAST. ONLY MINOR ADJUSTMENTS TO SKY COVER WITH THE EARLY EVENING UPDATE AND POPULATED LATEST SENSIBLE WEATHER ELEMENTS. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 250 PM CDT THU SEP 24 2015 CURRENT SURFACE ANALYSIS PLACES LOW OVER NORTHEAST NEBRASKA INTO SOUTHEAST SOUTH DAKOTA BRINGING LIGHT SOUTH/SOUTHEASTERLY LOW LEVEL FLOW OVER OUR AREA. UPPER LEVEL ANALYSIS PLACES LOW SLOWLY SLIDING FROM THE CENTRAL PLAINS INTO THE UPPER MIDWEST WITH RIDGE OVER THE WESTERN DAKOTAS/EASTERN MONTANA. LOW CLOUDS CONTINUE TO LINGER OVER PORTIONS OF THE AREA WITH MOIST LOW LEVEL FLOW...OTHERWISE QUIET CONDITIONS CONTINUE. FOR TONIGHT...EXPECT AREAS OF FOG TO RE-DEVELOP OVER THE AREA BY LATE THIS EVENING WITH AMPLE LOW LEVEL MOISTURE IN PLACE. OTHERWISE...A QUIET NIGHT IS EXPECTED AS UPPER RIDGE REMAINS OVER THE AREA. ON FRIDAY...FOG WILL LINGER INTO THE EARLY MORNING HOURS BEFORE DISSIPATING. OTHERWISE...A QUIET DAY IS EXPECTED WITH TEMPERATURES PUSHING ABOVE AVERAGE WITH UPPER RIDGE IN PLACE. SOUTHERLY WINDS WILL INCREASE BY MID DAY INTO THE AFTERNOON AS SURFACE LOW FORMS AND STARTS TO DEEPEN ON THE LEE SIDE OF THE ROCKIES. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 317 PM CDT THU SEP 24 2015 DRY AND WARM THROUGH SATURDAY AS OUR FLOW ALOFT REMAINS WEAK AND SOUTHWESTERLY. JET STREAM MIGRATES SOUTHWARD LATER THIS COMING WEEKEND INTO EARLY NEXT WEEK AND WILL STEER EMBEDDED MID LEVEL WAVES THROUGH THE LOCAL REGION...GIVING US A CHANCE FOR SHOWERS SAT NIGHT THROUGH TUESDAY. COOLER TEMPERATURES AS WELL...BUT STILL SEASONAL. MODELS THEN PORTRAY A STRONG SURFACE HIGH MOVING THROUGH THE REGION MID-WEEK AND SHOULD RESULT IN MAINLY DRY CONDITIONS AND PLEASANT TEMPERATURES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1245 AM CDT FRI SEP 25 2015 AT MIDNIGHT CDT...FOG WAS RE-DEVELOPING OVER MUCH OF EASTERN NORTH DAKOTA AS WELL AS ACROSS THE FAR NORTHERN PART OF THE STATE. VSBY AT KJMS WAS VARYING FROM 1/2SM TO 2SM. ROLLA WAS VARYING FROM 1/4SM TO 3SM WITH OVC002. FOG SHOULD CONTINUE TO DEVELOP AND EXPAND INTO CENTRAL NORTH DAKOTA...BRINGING IFR/LIFR CIGS AND VSBYS ACROSS CENTRAL NORTH DAKOTA...AND POSSIBLY PORTIONS OF THE WEST. WITH AN INCREASING SOUTHERLY FLOW FROM WEST TO EAST...THINK CONDITIONS IMPROVE FIRST IN THE WEST AND OVER HIGHER TERRAIN. CONDITIONS SHOULD IMPROVE OVER THE CENTRAL BY MID-MORNING FRIDAY. VFR CONDITIONS EXPECTED LATE MORNING THROUGH THE EARLY EVENING. THERE IS A HINT OF RETURNING FOG/LOW CLOUDS AFTER SUNSET FRIDAY EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JV SHORT TERM...JJS LONG TERM...NH AVIATION...JV
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
342 AM EDT FRI SEP 25 2015 .SYNOPSIS... AN AREA OF LOW PRESSURE NEAR THE ATLANTIC COASTLINE WILL FEED MOISTURE-RICH AIR INTO THE REGION THROUGH MOST OF THE WEEKEND... RESULTING IN A LENGTHY STRETCH OF WIDESPREAD LIGHT TO MODERATE RAINFALL. DRIER CONDITIONS WILL PREVAIL HEADING INTO LATE SUNDAY AND EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... VERY GOOD MOISTURE FLUX ALIGNED IN DEEP ATL PWAT PLUME CONTINUES ACROSS THE FA THIS MORNING. HEAVIER RAINFALL RATES HAVE BEEN MAINTAINED SOUTH WITH THE UPSLOPE REGIONS REMAINING IN A RELATIVE MIN WITHIN NE/LY FLOW BELOW 4 KFT. EXPECT THIS TREND TO CONTINUE OVER THE NEXT FEW HRS AND HAVE ADJ QPF GRIDS TO FAVOR WRN UPSTATE AND NE GA ALONG WITH FAR SW BR THROUGH 12Z. THE SFC LOW WILL MOVE INLAND ACROSS THE SC LOW COUNTRY AND SE/RN GA TODAY THEN STALL OUT WHILE BECOMING LESS DEFINED. MEANWHILE...A NE/RN SFC RIDGE WILL CONTINUE TO BUILD IN TO SOME DEGREE. THE 12 KM NAM IS LESS AMPLIFIED WITH THE RIDGING THAN THE 20 KM GFS AND THIS WILL MAKE A BIG DIFFERENCE AS TO THE AMOUNT OF ISENT LIFT AND 300 K SAT PRES DEFS. WITH LESS LLVL FORCING AND THE RAP MODEL SHOWING RELATIVE DRYING ALOFT THROUGHOUT THE DAY...A CASE CAN BE MADE FOR A RELATIVELY LOW QPF RESPONSE OVER THE UPSTATE AND SRN NE GA. ALTHOUGH ISOL NAM CONVEC SOUTH WOULD ADD LOCALIZED HIGH AMOUNTS OF QPF OVER AREAS WITH THE BEST 24-PRECIP. THE GFS IS SOMEWHAT SIMILAR WITH THIS IDEA YET WITH NO GOOD CONVEC POTENTIAL AND A LITTLE MORE NON/MTN STRATIFORM QPF RESPONSE. IN ANY CASE...THE BEST AREA FOR PRECIP ACCUMS THROUGH THE PERIOD WILL BE ALONG THE BR WHERE AN INCH TO AN INCH AND A QUARTER COULD FALL THROUGH 12Z SAT AS LLVL FLOW BTW 3-5 KFT VEERS. THE NON/MTNS WILL GENERALLY SEE AROUND A HALF INCH DURING THIS TIME. HOWEVER...CONVEC WILL BE THE WILDCARD SOUTH IF ENUF MLVL DRYING OCCURS AS STATED ABOVE. THUS...LOCALIZED FLOODING CONCERNS ARE A LITTLE UNCERTAIN...BUT IF HYDRO BECOMES AN ISSUE...IT WILL BE ACROSS THE SRN ZONES AND/OR THE ERN FACING BR LATE TODAY. MAXES WILL BE HELD ABOUT 10-12 DEGREES BELOW NORMAL MOST LOCALES WITH MINS A COUPLE DEGREES ABOVE NORMAL. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 315 AM FRIDAY...MODELS STILL DISAGREE WITH HOW THE ONGOING RAIN EVENT WILL UNWIND ON SATURDAY AND SATURDAY NIGHT...ALTHO THERE IS GENERAL AGREEMENT IN SHIFTING THE DEEPER MOISTURE AND BETTER FORCING TO THE N BY SATURDAY AFTERNOON. EVEN THE NAM...WHICH WAS A HOLDOUT...NOW HAS THE BEST Q-CONVERGENCE AND UPPER DIVERGENCE ACROSS VA/WV BY 18Z SATURDAY. THE DEEP MOISTURE PLUME SHOULD ALSO BE DIRECTED UP ACROSS THE DELMARVA/TIDEWATER REGION BY THAT TIME AS WELL. THAT SUGGESTS WE SHOULD NOT HAVE MUCH OF A HEAVY PRECIP THREAT MUCH BEYOND 12Z SATURDAY...WHICH IS GOOD. THE PROBLEM IS MAINLY WITH LOW LEVEL MOISTURE AND FORCING... AND THE NAM STILL HAS MUCH MORE ISENTROPIC LIFT OVER THE NC PIEDMONT/FOOTHILLS AND A MORE EASTERLY FLOW AT 850MB DIRECTED AT THE NC MTNS. THUS...NO SURPRISE THAT THE NAM HOLDS ONTO PRECIP PRODUCTION ACROSS THOSE AREAS RIGHT THRU SUNDAY NIGHT. MEANWHILE...THE GFS OPENS UP MORE OF A HOLE ACROSS UPSTATE SC AND GRADUALLY ELIMINATES PRECIP FROM THERE TO THE POINT WHERE IT HAS MINIMAL PRECIP ACROSS THE MTNS FROM SATURDAY NIGHT ONWARD...AND IS BASICALLY DRY ELSEWHERE. THE ECMWF STILL OFFERS A DECENT COMPROMISE. THUS...WILL RAMP DOWN THE POP SATURDAY...AND THEN HOLD ONTO THE LIKELY NEAR THE NC BLUE RIDGE SATURDAY NIGHT WHERE THE LLVL FORCING WOULD BE BEST. POP WILL BE KEPT AT CHC ACROSS THE REST OF THE AREA. ON SUNDAY...THE CHANCE POP GETS PARED BACK TO THE MTNS WHERE ANY REMAINING LIFT WOULD BE THE BEST. THE REST OF THE FCST HAS TOKEN CHC/SLIGHT CHC POP UNTIL WE GET BETTER MODEL CONSENSUS. TEMPS WILL BE SEASONALLY COOL AS WE DEAL WITH THE REMNANTS OF THE COLD AIR DAMMING WEDGE. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 340 AM FRIDAY...HAVE TABLED THE MEDIUM RANGE FOR NOW DUE TO ONGOING FLOOD CONCERNS. NO CHANGES WERE MADE AT THIS TIME. REMAINDER OF PREVIOUS DISCUSSION... THE EXTENDED PERIOD BEGINS WITH THE WEEKEND RAINFALL EVENT ON THE WANE AND DRIER CONDITIONS BUILDING IN ACROSS THE FORECAST AREA. WHILE FLOW ALOFT WILL BE SOUTHERLY THANKS TO A CUT-OFF 500MB LOW OVER SOUTH TEXAS AND AN ANTICYCLONE OVER THE WESTERN SARGASSO SEA...SURFACE HIGH PRESSURE AND A LACK OF NOTABLE SHORTWAVES IN THE FLOW ALOFT SHOULD KEEP THE AREA MOSTLY DRY THROUGH MIDDAY TUESDAY. THEREAFTER...THERE IS GENERAL AGREEMENT THAT A LONGWAVE TROUGH WILL MOVE ACROSS THE NORTHERN HALF OF THE U.S. AND CANADA AND AN ASSOCIATED SURFACE LOW PRESSURE SYSTEM AND ATTENDANT COLD FRONT WILL APPROACH OUR AREA ON WEDNESDAY. BOTH THE GFS AND THE ECMWF ARE NOT EXCITED ABOUT NOTABLE RAINFALL AS A RESULT OF THE FRONTAL PASSAGE...HOWEVER...THE GFS CONTINUES TO BE BULLISH ON A MODEST BUT WELL-DEFINED SURFACE LOW MOVING NORTHWARD OVER THE CENTRAL GULF AND APPROACHING THE LOUISIANA COAST BY TUESDAY AFTERNOON. THE ECMWF WEAKENS THE LOW TO AN OPEN TROUGH OVER THE NORTHERN GULF. BOTH MODELS DO NOT BRING THE FEATURE INLAND...HOWEVER THE GFS KEEPS THE SOUTHERN APPALACHIANS IN A MOISTURE-RICH ENVIRONMENT WITH A TROPICAL CONNECTION TO THE CARIBBEAN AND EJECTS ROUNDS OR BANDS OF CONVECTIVE PRECIP NORTH FROM THE GULF LOW ACROSS THE DEEP SOUTH AND INTO OUR AREA BEGINNING TUESDAY EVENING AND LASTING THROUGH WEDNESDAY. THE ECMWF PERSISTS WITH WEAK NORTHEASTERLY FLOW ACROSS MUCH OF THE SOUTHEAST HEADING INTO THURSDAY. AT THIS TIME THE FORECAST MAINTAINS SLIGHT CHANCE TO CHANCE POPS DURING THE MID-WEEK PERIOD GIVEN THE DECENT MOISTURE THAT REMAINS IN PLACE FOLLOWING THE EVENT ENDING ON SUNDAY...THE ANTICIPATED FRONTAL PASSAGE...AND THE PERSISTENCE OF BOTH MODELS OVER THE PAST FEW RUNS OF SUGGESTING SOME ACTIVITY IN THE GULF MOVING TOWARDS THE COAST. NEVERTHELESS...BOTH THE ECMWF AND GFS AGREE THAT A STRONG 1028MB SURFACE HIGH BUILDS IN ACROSS THE NORTHEAST U.S. ON THE CONFLUENT SIDE OF THE UPPER-LEVEL LONGWAVE TROUGH AND WEDGES DOWN ACROSS MUCH OF THE SOUTHEAST U.S.... SIGNIFICANTLY DRYING US OUT THROUGH THE END OF THE PERIOD ON FRIDAY MORNING. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... 0205 AM UPDATE...ADDED A WS GROUP TO KCLT THROUGH DAYBREAK. TCLT VAD PROFILE SHOWING NE/LY LLVL JET DROPPING DOWN PERIODICALLY TO ARND 2 KFT. AT KCLT AND ELSEWHERE...VERY GOOD MOISTURE FLUX CONTINUING OFF THE ATL ASSOCIATED WITH A DEEP PW PLUME HAS MAINTAINED STEADY STATE FLIGHT CONDS. RAP SOUNDINGS SHOW SAT PROFILES THROUGH THE PERIOD WITH LITTLE WAVERING IN CIGS OUTSIDE OF LIMITED NOCTURNAL LIFTING. GENERALLY...MFVR CIGS WILL BE MAINTAINED OVERNIGHT WITH POSSIBLE DIPS INTO IFR ARND AND THROUGH DAYBREAK ESP IN ISOL SHRA. THEN A LIFT INTO LOW VFR PROBABLE LATE MORNING. WINDS REMAIN NE/LY NON/MTNS WITH MODERATE GUSTS THROUGH THE OVERNIGHT AS P/GRAD LOOSENS. KAVL AND MTN VICINITY AIRPORTS WILL EXPERIENCE WS ISSUES LATE PERIOD AS LLVL JET SWINGS AROUND SFC TROF. A DECREASE IN CIG HEIGHTS TO MFVR/IFR IS ANTICIPATED AGAIN LATTER PERIOD ALL SITES. OUTLOOK...DEEP MOISTURE AND WIDESPREAD LIFT WILL LIKELY RESULT IN RESTRICTIVE CEILINGS AND VISIBILITY PERIODICALLY THRU SATURDAY. IN ADDITION...RAINFALL WILL BE MODERATE TO HEAVY AT TIMES THROUGH SATURDAY. CONFIDENCE TABLE... 07-13Z 13-19Z 19-01Z 01-06Z KCLT HIGH 100% HIGH 92% HIGH 100% HIGH 96% KGSP MED 66% HIGH 100% HIGH 100% HIGH 95% KAVL HIGH 91% HIGH 91% HIGH 91% HIGH 94% KHKY HIGH 81% HIGH 100% HIGH 100% HIGH 100% KGMU MED 66% HIGH 100% HIGH 100% HIGH 95% KAND HIGH 98% HIGH 100% HIGH 98% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO/JMP NEAR TERM...SBK SHORT TERM...PM LONG TERM...JMP/PM AVIATION...SBK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
211 AM EDT FRI SEP 25 2015 .SYNOPSIS... AN AREA OF LOW PRESSURE NEAR THE ATLANTIC COASTLINE WILL FEED MOISTURE-RICH AIR INTO THE REGION THROUGH MOST OF THE WEEKEND... RESULTING IN A LENGTHY STRETCH OF WIDESPREAD LIGHT TO MODERATE RAINFALL. DRIER CONDITIONS WILL PREVAIL HEADING INTO LATE SUNDAY AND EARLY NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... AS OF 130 AM...PRECIP REMAINS LIGHT TO MODERATE MOST LOCALES THIS MORNING...WITH SIGFNT RATES OCCURRING ACROSS THE FAR SRN ZONES...MAINLY OVER GREENWOOD/ABBEVILLE COUNTIES. RADAR PRECIP ESTIMATES ARE BIASED ON THE LOW END AND WITH GOOD AMOUNTS OF PREVIOUS RAIN ACROSS THOSE AREAS WILL ISSUE A FFW THROUGH 0830Z. NEARLY STEADY STATE T/TDS REQUIRED LITTLE GRID ADJS. AS OF 10 PM...RAINFALL CONTINUES ACROSS ALL COUNTIES IN THE CWA. SINCE 9 PM...RADAR RAINFALL ESTIMATES AND AUTOMATED RAIN GAUGES INDICATED THAT RAINFALL RATES IN THE HEAVIEST SHOWERS RANGED NEAR ONE HALF OF AN INCH PER HOUR...WITH COMMON VALUES AROUND 0.3 INCHES. ONE HOUR FFG REMAINS SLIGHTLY ABOVE 3 IN / HR FOR MOST AREAS. MODEL QPF WITHIN RIVER MODELING INDICATE THAT THE LARGER RIVERS APPEAR IN LITTLE THREAT OF FLOODING THROUGH FRI AM. AT 2Z...TCLT VWP INDICATED THAT WINDS AROUND 5 KFT HAVE INCREASED TO 40 KTS. IR SATELLITE AND RADAR INDICATED A SIGNIFICANT CLUSTER OF MODERATE TO HEAVY RAIN DEVELOPING OVER THE MIDLANDS...TRACKING TOWARD THE UPPER SAVANNAH RIVER VALLEY. THE UPSLOPE FLOW...DEEP ISENTROPIC LIFT...AND EXPANDING Q-VECTOR CONVERGENCE WILL INCREASE RAINFALL RATES TONIGHT. FOR THE UPDATE...I WILL INCREASE POPS TO TRIPLE DIGITS AND CLICK QPF A LITTLE HIGHER. NEARLY STEADY TEMPERATURES WILL REMAIN TONIGHT. AS OF 8 PM...VERY IMPRESSIVE STREAM OF WATER VAPOR...FROM SOUTH OF CUBA NORTH ACROSS THE WESTERN CAROLINAS. BLENDED TOTAL PW PRODUCT INDICATES A PLUME OF GREATER THAN 2 INCHES BUILDING WEST ACROSS THE COASTAL PLAIN. NAM AND RAP INDICATES THAT LLVL WINDS WILL INCREASE FROM THE EAST...STRENGTHENING TO AROUND 30 KTS. THE LLVL FLOW WILL CREATE WIDESPREAD LIFT OVER A SFC RIDGE AND ALONG THE EAST FACING SLOPES. IN ADDITION...GFS40 SHOWS A FIELD OF Q-VECTOR CONVERGENCE DEVELOPING ACROSS THE CWA...ON THE NE SIDE OF A CLOSED MID LEVEL LOW. THERE IS NO QUESTION THAT RAINFALL WILL INCREASE ACROSS THE CWA DURING THE OVERNIGHT HOURS. I WILL UPDATE TO INCREASE POPS TO 100 PERCENT...OR VERY CLOSE TO IT. TEMPERATURES MAY REMAIN NEARLY STEADY THROUGH THE REST OF TONIGHT. AS OF 530 PM...LATEST SATELLITE LOOP SHOWS A BAND OF DEEP CONVECTION OFF THE CENTRAL SC SHORE...DRIFTING NORTHWARD. A BAND OF COLDER CLOUD TOPS HAS PIVOTED BACK TOWARD THE COAST...RESULTING IN WARMING CLOUD TEMPERATURES ACROSS THE MIDLANDS OF SC AND CENTRAL GA. BASED ON THE SATELLITE TRENDS...THE CURRENT BAND OF LIGHT RAINFALL MAY SLIDE TOWARD THE WEST...FOLLOWED BY CLUSTERS OF LIGHT RAIN HEADED INTO THIS EVENING. THE ENVIRONMENT BECOMES MORE DYNAMIC LATER THIS EVENING AND OVERNIGHT. NAM AND RAP FORECAST SOUNDINGS INDICATE A DEEP LAYER OF EAST LLVL FLOW ACROSS THE WESTERN CAROLINAS. PWS WILL INCREASE TO NEARLY 2 INCHES WITH THE WARM CLOUD LAYER DEEPENING TO AROUND 13 KFT. IN ADDITION...GFS40S SHOWS A FIELD OF Q-VECTOR CONVERGENCE DEVELOPING ACROSS THE CWA... ON THE NE SIDE OF A CLOSED MID LEVEL LOW. I WILL UPDATE THE FORECAST TO ADJUST POP TIMING AND INCREASE QPF ACROSS THE UPSLOPE AREAS. AT 230 PM EDT THURSDAY...AN UPPER LOW OVER THE SE AND AND ASSOCIATED SURFACE LOW OVER OFF THE GA COAST WILL CONTINUE TO SEND MOISTURE INLAND TOWARD THE BLUE RIDGE TONIGHT AND FRIDAY. THE COMBINATION OF DIFFLUENT FLOW ALOFT...INCREASING EASTERLY LOW LEVEL UPSLOPE FLOW...INCREASING EASTERLY ISENTROPIC UPGLIDE OVER A SURFACE RIDGE...AND MOISTURE WELL ABOVE NORMAL...WILL FAVOR THE DEVELOPMENT OF HEAVY PRECIPITATION ALONG THE EAST FACING BLUE RIDGE. ALTHOUGH MUCH OF THE AREA IS CURRENTLY IN DROUGHT...LOCALIZED FLOODING COULD OCCUR IN SMALLER STREAM BASIN AND HILLY TERRAIN. A FLASH FLOOD WATCH WILL BE NOT ISSUED OUR BLUE RIDGE AREA...AS IT APPEARS PRECIPITANT WILL GRADUALLY SPREAD NE FROM THE UPPER SAVANNAH RIVER VALLEY TO THE NC MOUNTAINS. TEMPERATURES WILL RUN BELOW NORMAL IN COOL NE SURFACE FLOW...ESPECIALLY MAXIMUMS UNDER CLOUD COVER. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... AS OF 255 PM THURSDAY...ALTHOUGH GUIDANCE CONTINUES TO SHOW WIDESPREAD RAIN AT THE START OF THE PERIOD THEN GRADUALLY DIMINISHING IN COVERAGE BY THE END OF THE PERIOD...THEY HAVE BACKED OFF ON AMOUNT OF QPF. MANY OF THE TRADITIONAL PARAMETERS NEEDED FOR FLOODING TYPE RAINFALL ARE NOT THERE. OPS MDLS SHOW PW VALUES ARE UP TO 190 PERCENT OF NORMAL...BUT THE ENSEMBLE GUIDANCE SHOWS 1 TO MAYBE 1.5 STANDARD DEVIATIONS ABOVE NORMAL. WHILE THERE IS SOME UPPER DIVERGENCE ASSOCIATED WITH THE UPPER JET MAX...1 STD DEVIATION ABOVE NORMAL...THIS DISSIPATES ON SAT AS THE JET MOVES OUT OF THE AREA. THE MAIN FORCING WILL COME FROM STRONG UPSLOPE FLOW WITH THE ENSEMBLE GUIDANCE SHOWING H85 ELY FLOW UP TO 4 STD DEVIATIONS ABOVE NORMAL. THERE WILL ALSO BE STRONG ISENTROPIC LIFT IN THE VERY MOIST LOW LEVELS. THE ENSEMBLE GUIDANCE CONTINUES TO SHOW A NORTHWARD SHIFT IN THE BEST H85 FLOW THRU THE PERIOD...ALTHOUGH THE SREF DOES KEEP IT OVER OUR PORTION OF THE BLUE RIDGE LONGER THAN THE GEFS. GIVEN THESE FACTORS...WPC HAS DROPPED THE QPF FCST ACROSS THE AREA. HAVE FOLLOWED THESE TRENDS AS WELL. THAT SAID...THIS STILL PUTS 1 TO 3 INCHES OF RAIN ACROSS AND NEAR THE NRN BLUE RIDGE...SO WILL HAVE TO KEEP AN EYE ON THE RAINFALL AMOUNTS. CANNOT RULE OUT FLOODING... BUT IT APPEARS TO NOT BE WIDESPREAD AND WARRANT A WATCH AT THIS TIME. HIGHEST POPS WILL BE ALONG AND NEAR THE BLUE RIDGE THRU THE PERIOD...WITH LOWER POP ACROSS THE SWRN CWFA. WITH A WEDGE PATTERN IN PLACE AND CONTINUED RAINFALL...EXPECT BREEZY AND COOL CONDITIONS EACH DAY. HIGHS WILL BE NEARLY 10 DEGREES BELOW NORMAL ON SAT THEN RISE A COUPLE OF DEGREES SUN. LOWS WILL BE ABOUT 5 DEGREES ABOVE NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AS OF 230PM THURSDAY...THE EXTENDED PERIOD BEGINS ON SUNDAY NIGHT WITH THE WEEKEND RAINFALL EVENT ON THE WANE AND DRIER CONDITIONS BUILDING IN ACROSS THE FORECAST AREA. WHILE FLOW ALOFT WILL BE SOUTHERLY THANKS TO A CUT-OFF 500MB LOW OVER SOUTH TEXAS AND AN ANTICYCLONE OVER THE WESTERN SARGASSO SEA...SURFACE HIGH PRESSURE AND A LACK OF NOTABLE SHORTWAVES IN THE FLOW ALOFT SHOULD KEEP THE AREA MOSTLY DRY THROUGH MIDDAY TUESDAY. THEREAFTER...THERE IS GENERAL AGREEMENT THAT A LONGWAVE TROUGH WILL MOVE ACROSS THE NORTHERN HALF OF THE U.S. AND CANADA AND AN ASSOCIATED SURFACE LOW PRESSURE SYSTEM AND ATTENDANT COLD FRONT WILL APPROACH OUR AREA ON WEDNESDAY. BOTH THE GFS AND THE ECMWF ARE NOT EXCITED ABOUT NOTABLE RAINFALL AS A RESULT OF THE FRONTAL PASSAGE...HOWEVER...THE GFS CONTINUES TO BE BULLISH ON A MODEST BUT WELL-DEFINED SURFACE LOW MOVING NORTHWARD OVER THE CENTRAL GULF AND APPROACHING THE LOUISIANA COAST BY TUESDAY AFTERNOON. THE ECMWF WEAKENS THE LOW TO AN OPEN TROUGH OVER THE NORTHERN GULF. BOTH MODELS DO NOT BRING THE FEATURE INLAND...HOWEVER THE GFS KEEPS THE SOUTHERN APPALACHIANS IN A MOISTURE-RICH ENVIRONMENT WITH A TROPICAL CONNECTION TO THE CARIBBEAN AND EJECTS ROUNDS OR BANDS OF CONVECTIVE PRECIP NORTH FROM THE GULF LOW ACROSS THE DEEP SOUTH AND INTO OUR AREA BEGINNING TUESDAY EVENING AND LASTING THROUGH WEDNESDAY. THE ECMWF PERSISTS WITH WEAK NORTHEASTERLY FLOW ACROSS MUCH OF THE SOUTHEAST HEADING INTO THURSDAY. AT THIS TIME THE FORECAST MAINTAINS SLIGHT CHANCE TO CHANCE POPS DURING THE MID-WEEK PERIOD GIVEN THE DECENT MOISTURE THAT REMAINS IN PLACE FOLLOWING THE EVENT ENDING ON SUNDAY...THE ANTICIPATED FRONTAL PASSAGE...AND THE PERSISTENCE OF BOTH MODELS OVER THE PAST FEW RUNS OF SUGGESTING SOME ACTIVITY IN THE GULF MOVING TOWARDS THE COAST. NEVERTHELESS...BOTH THE ECMWF AND GFS AGREE THAT A STRONG 1028MB SURFACE HIGH BUILDS IN ACROSS THE NORTHEAST U.S. ON THE CONFLUENT SIDE OF THE UPPER-LEVEL LONGWAVE TROUGH AND WEDGES DOWN ACROSS MUCH OF THE SOUTHEAST U.S.... SIGNIFICANTLY DRYING US OUT THROUGH THE END OF THE PERIOD ON FRIDAY MORNING. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... 0205 AM UPDATE...ADDED A WS GROUP TO KCLT THROUGH DAYBREAK. TCLT VAD PROFILE SHOWING NE/LY LLVL JET DROPPING DOWN PERIODICALLY TO ARND 2 KFT. AT KCLT AND ELSEWHERE...VERY GOOD MOISTURE FLUX CONTINUING OFF THE ATL ASSOCIATED WITH A DEEP PW PLUME HAS MAINTAINED STEADY STATE FLIGHT CONDS. RAP SOUNDINGS SHOW SAT PROFILES THROUGH THE PERIOD WITH LITTLE WAVERING IN CIGS OUTSIDE OF LIMITED NOCTURNAL LIFTING. GENERALLY...MFVR CIGS WILL BE MAINTAINED OVERNIGHT WITH POSSIBLE DIPS INTO IFR ARND AND THROUGH DAYBREAK ESP IN ISOL SHRA. THEN A LIFT INTO LOW VFR PROBABLE LATE MORNING. WINDS REMAIN NE/LY NON/MTNS WITH MODERATE GUSTS THROUGH THE OVERNIGHT AS P/GRAD LOOSENS. KAVL AND MTN VICINITY AIRPORTS WILL EXPERIENCE WS ISSUES LATE PERIOD AS LLVL JET SWINGS AROUND SFC TROF. A DECREASE IN CIG HEIGHTS TO MFVR/IFR IS ANTICIPATED AGAIN LATTER PERIOD ALL SITES. OUTLOOK...DEEP MOISTURE AND WIDESPREAD LIFT WILL LIKELY RESULT IN RESTRICTIVE CEILINGS AND VISIBILITY PERIODICALLY THRU SATURDAY. IN ADDITION...RAINFALL WILL BE MODERATE TO HEAVY AT TIMES THROUGH SATURDAY. CONFIDENCE TABLE... 06-12Z 12-18Z 18-24Z 00-06Z KCLT HIGH 100% HIGH 93% HIGH 100% HIGH 97% KGSP MED 65% HIGH 100% HIGH 100% HIGH 95% KAVL HIGH 80% HIGH 91% HIGH 96% HIGH 94% KHKY HIGH 84% HIGH 100% HIGH 100% HIGH 100% KGMU MED 64% HIGH 100% HIGH 100% HIGH 95% KAND HIGH 97% HIGH 100% HIGH 98% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...JMP NEAR TERM...NED/SBK SHORT TERM...RWH LONG TERM...JMP AVIATION...SBK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
138 AM EDT FRI SEP 25 2015 .SYNOPSIS... AN AREA OF LOW PRESSURE NEAR THE ATLANTIC COASTLINE WILL FEED MOISTURE-RICH AIR INTO THE REGION THROUGH MOST OF THE WEEKEND... RESULTING IN A LENGTHY STRETCH OF WIDESPREAD LIGHT TO MODERATE RAINFALL. DRIER CONDITIONS WILL PREVAIL HEADING INTO LATE SUNDAY AND EARLY NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... AS OF 130 AM...PRECIP REMAINS LIGHT TO MODERATE MOST LOCALES THIS MORNING...WITH SIGFNT RATES OCCURRING ACROSS THE FAR SRN ZONES...MAINLY OVER GREENWOOD/ABBEVILLE COUNTIES. RADAR PRECIP ESTIMATES ARE BIASED ON THE LOW END AND WITH GOOD AMOUNTS OF PREVIOUS RAIN ACROSS THOSE AREAS WILL ISSUE A FFW THROUGH 0830Z. NEARLY STEADY STATE T/TDS REQUIRED LITTLE GRID ADJS. AS OF 10 PM...RAINFALL CONTINUES ACROSS ALL COUNTIES IN THE CWA. SINCE 9 PM...RADAR RAINFALL ESTIMATES AND AUTOMATED RAIN GAUGES INDICATED THAT RAINFALL RATES IN THE HEAVIEST SHOWERS RANGED NEAR ONE HALF OF AN INCH PER HOUR...WITH COMMON VALUES AROUND 0.3 INCHES. ONE HOUR FFG REMAINS SLIGHTLY ABOVE 3 IN / HR FOR MOST AREAS. MODEL QPF WITHIN RIVER MODELING INDICATE THAT THE LARGER RIVERS APPEAR IN LITTLE THREAT OF FLOODING THROUGH FRI AM. AT 2Z...TCLT VWP INDICATED THAT WINDS AROUND 5 KFT HAVE INCREASED TO 40 KTS. IR SATELLITE AND RADAR INDICATED A SIGNIFICANT CLUSTER OF MODERATE TO HEAVY RAIN DEVELOPING OVER THE MIDLANDS...TRACKING TOWARD THE UPPER SAVANNAH RIVER VALLEY. THE UPSLOPE FLOW...DEEP ISENTROPIC LIFT...AND EXPANDING Q-VECTOR CONVERGENCE WILL INCREASE RAINFALL RATES TONIGHT. FOR THE UPDATE...I WILL INCREASE POPS TO TRIPLE DIGITS AND CLICK QPF A LITTLE HIGHER. NEARLY STEADY TEMPERATURES WILL REMAIN TONIGHT. AS OF 8 PM...VERY IMPRESSIVE STREAM OF WATER VAPOR...FROM SOUTH OF CUBA NORTH ACROSS THE WESTERN CAROLINAS. BLENDED TOTAL PW PRODUCT INDICATES A PLUME OF GREATER THAN 2 INCHES BUILDING WEST ACROSS THE COASTAL PLAIN. NAM AND RAP INDICATES THAT LLVL WINDS WILL INCREASE FROM THE EAST...STRENGTHENING TO AROUND 30 KTS. THE LLVL FLOW WILL CREATE WIDESPREAD LIFT OVER A SFC RIDGE AND ALONG THE EAST FACING SLOPES. IN ADDITION...GFS40 SHOWS A FIELD OF Q-VECTOR CONVERGENCE DEVELOPING ACROSS THE CWA...ON THE NE SIDE OF A CLOSED MID LEVEL LOW. THERE IS NO QUESTION THAT RAINFALL WILL INCREASE ACROSS THE CWA DURING THE OVERNIGHT HOURS. I WILL UPDATE TO INCREASE POPS TO 100 PERCENT...OR VERY CLOSE TO IT. TEMPERATURES MAY REMAIN NEARLY STEADY THROUGH THE REST OF TONIGHT. AS OF 530 PM...LATEST SATELLITE LOOP SHOWS A BAND OF DEEP CONVECTION OFF THE CENTRAL SC SHORE...DRIFTING NORTHWARD. A BAND OF COLDER CLOUD TOPS HAS PIVOTED BACK TOWARD THE COAST...RESULTING IN WARMING CLOUD TEMPERATURES ACROSS THE MIDLANDS OF SC AND CENTRAL GA. BASED ON THE SATELLITE TRENDS...THE CURRENT BAND OF LIGHT RAINFALL MAY SLIDE TOWARD THE WEST...FOLLOWED BY CLUSTERS OF LIGHT RAIN HEADED INTO THIS EVENING. THE ENVIRONMENT BECOMES MORE DYNAMIC LATER THIS EVENING AND OVERNIGHT. NAM AND RAP FORECAST SOUNDINGS INDICATE A DEEP LAYER OF EAST LLVL FLOW ACROSS THE WESTERN CAROLINAS. PWS WILL INCREASE TO NEARLY 2 INCHES WITH THE WARM CLOUD LAYER DEEPENING TO AROUND 13 KFT. IN ADDITION...GFS40S SHOWS A FIELD OF Q-VECTOR CONVERGENCE DEVELOPING ACROSS THE CWA... ON THE NE SIDE OF A CLOSED MID LEVEL LOW. I WILL UPDATE THE FORECAST TO ADJUST POP TIMING AND INCREASE QPF ACROSS THE UPSLOPE AREAS. AT 230 PM EDT THURSDAY...AN UPPER LOW OVER THE SE AND AND ASSOCIATED SURFACE LOW OVER OFF THE GA COAST WILL CONTINUE TO SEND MOISTURE INLAND TOWARD THE BLUE RIDGE TONIGHT AND FRIDAY. THE COMBINATION OF DIFFLUENT FLOW ALOFT...INCREASING EASTERLY LOW LEVEL UPSLOPE FLOW...INCREASING EASTERLY ISENTROPIC UPGLIDE OVER A SURFACE RIDGE...AND MOISTURE WELL ABOVE NORMAL...WILL FAVOR THE DEVELOPMENT OF HEAVY PRECIPITATION ALONG THE EAST FACING BLUE RIDGE. ALTHOUGH MUCH OF THE AREA IS CURRENTLY IN DROUGHT...LOCALIZED FLOODING COULD OCCUR IN SMALLER STREAM BASIN AND HILLY TERRAIN. A FLASH FLOOD WATCH WILL BE NOT ISSUED OUR BLUE RIDGE AREA...AS IT APPEARS PRECIPITANT WILL GRADUALLY SPREAD NE FROM THE UPPER SAVANNAH RIVER VALLEY TO THE NC MOUNTAINS. TEMPERATURES WILL RUN BELOW NORMAL IN COOL NE SURFACE FLOW...ESPECIALLY MAXIMUMS UNDER CLOUD COVER. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... AS OF 255 PM THURSDAY...ALTHOUGH GUIDANCE CONTINUES TO SHOW WIDESPREAD RAIN AT THE START OF THE PERIOD THEN GRADUALLY DIMINISHING IN COVERAGE BY THE END OF THE PERIOD...THEY HAVE BACKED OFF ON AMOUNT OF QPF. MANY OF THE TRADITIONAL PARAMETERS NEEDED FOR FLOODING TYPE RAINFALL ARE NOT THERE. OPS MDLS SHOW PW VALUES ARE UP TO 190 PERCENT OF NORMAL...BUT THE ENSEMBLE GUIDANCE SHOWS 1 TO MAYBE 1.5 STANDARD DEVIATIONS ABOVE NORMAL. WHILE THERE IS SOME UPPER DIVERGENCE ASSOCIATED WITH THE UPPER JET MAX...1 STD DEVIATION ABOVE NORMAL...THIS DISSIPATES ON SAT AS THE JET MOVES OUT OF THE AREA. THE MAIN FORCING WILL COME FROM STRONG UPSLOPE FLOW WITH THE ENSEMBLE GUIDANCE SHOWING H85 ELY FLOW UP TO 4 STD DEVIATIONS ABOVE NORMAL. THERE WILL ALSO BE STRONG ISENTROPIC LIFT IN THE VERY MOIST LOW LEVELS. THE ENSEMBLE GUIDANCE CONTINUES TO SHOW A NORTHWARD SHIFT IN THE BEST H85 FLOW THRU THE PERIOD...ALTHOUGH THE SREF DOES KEEP IT OVER OUR PORTION OF THE BLUE RIDGE LONGER THAN THE GEFS. GIVEN THESE FACTORS...WPC HAS DROPPED THE QPF FCST ACROSS THE AREA. HAVE FOLLOWED THESE TRENDS AS WELL. THAT SAID...THIS STILL PUTS 1 TO 3 INCHES OF RAIN ACROSS AND NEAR THE NRN BLUE RIDGE...SO WILL HAVE TO KEEP AN EYE ON THE RAINFALL AMOUNTS. CANNOT RULE OUT FLOODING... BUT IT APPEARS TO NOT BE WIDESPREAD AND WARRANT A WATCH AT THIS TIME. HIGHEST POPS WILL BE ALONG AND NEAR THE BLUE RIDGE THRU THE PERIOD...WITH LOWER POP ACROSS THE SWRN CWFA. WITH A WEDGE PATTERN IN PLACE AND CONTINUED RAINFALL...EXPECT BREEZY AND COOL CONDITIONS EACH DAY. HIGHS WILL BE NEARLY 10 DEGREES BELOW NORMAL ON SAT THEN RISE A COUPLE OF DEGREES SUN. LOWS WILL BE ABOUT 5 DEGREES ABOVE NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AS OF 230PM THURSDAY...THE EXTENDED PERIOD BEGINS ON SUNDAY NIGHT WITH THE WEEKEND RAINFALL EVENT ON THE WANE AND DRIER CONDITIONS BUILDING IN ACROSS THE FORECAST AREA. WHILE FLOW ALOFT WILL BE SOUTHERLY THANKS TO A CUT-OFF 500MB LOW OVER SOUTH TEXAS AND AN ANTICYCLONE OVER THE WESTERN SARGASSO SEA...SURFACE HIGH PRESSURE AND A LACK OF NOTABLE SHORTWAVES IN THE FLOW ALOFT SHOULD KEEP THE AREA MOSTLY DRY THROUGH MIDDAY TUESDAY. THEREAFTER...THERE IS GENERAL AGREEMENT THAT A LONGWAVE TROUGH WILL MOVE ACROSS THE NORTHERN HALF OF THE U.S. AND CANADA AND AN ASSOCIATED SURFACE LOW PRESSURE SYSTEM AND ATTENDANT COLD FRONT WILL APPROACH OUR AREA ON WEDNESDAY. BOTH THE GFS AND THE ECMWF ARE NOT EXCITED ABOUT NOTABLE RAINFALL AS A RESULT OF THE FRONTAL PASSAGE...HOWEVER...THE GFS CONTINUES TO BE BULLISH ON A MODEST BUT WELL-DEFINED SURFACE LOW MOVING NORTHWARD OVER THE CENTRAL GULF AND APPROACHING THE LOUISIANA COAST BY TUESDAY AFTERNOON. THE ECMWF WEAKENS THE LOW TO AN OPEN TROUGH OVER THE NORTHERN GULF. BOTH MODELS DO NOT BRING THE FEATURE INLAND...HOWEVER THE GFS KEEPS THE SOUTHERN APPALACHIANS IN A MOISTURE-RICH ENVIRONMENT WITH A TROPICAL CONNECTION TO THE CARIBBEAN AND EJECTS ROUNDS OR BANDS OF CONVECTIVE PRECIP NORTH FROM THE GULF LOW ACROSS THE DEEP SOUTH AND INTO OUR AREA BEGINNING TUESDAY EVENING AND LASTING THROUGH WEDNESDAY. THE ECMWF PERSISTS WITH WEAK NORTHEASTERLY FLOW ACROSS MUCH OF THE SOUTHEAST HEADING INTO THURSDAY. AT THIS TIME THE FORECAST MAINTAINS SLIGHT CHANCE TO CHANCE POPS DURING THE MID-WEEK PERIOD GIVEN THE DECENT MOISTURE THAT REMAINS IN PLACE FOLLOWING THE EVENT ENDING ON SUNDAY...THE ANTICIPATED FRONTAL PASSAGE...AND THE PERSISTENCE OF BOTH MODELS OVER THE PAST FEW RUNS OF SUGGESTING SOME ACTIVITY IN THE GULF MOVING TOWARDS THE COAST. NEVERTHELESS...BOTH THE ECMWF AND GFS AGREE THAT A STRONG 1028MB SURFACE HIGH BUILDS IN ACROSS THE NORTHEAST U.S. ON THE CONFLUENT SIDE OF THE UPPER-LEVEL LONGWAVE TROUGH AND WEDGES DOWN ACROSS MUCH OF THE SOUTHEAST U.S.... SIGNIFICANTLY DRYING US OUT THROUGH THE END OF THE PERIOD ON FRIDAY MORNING. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AT KCLT AND ELSEWHERE...VERY GOOD MOISTURE FLUX CONTINUING OFF THE ATL ASSOCIATED WITH A DEEP PW PLUME HAS MAINTAINED STEADY STATE FLIGHT CONDS. RAP SOUNDINGS SHOW SAT PROFILES THROUGH THE PERIOD WITH LITTLE WAVERING IN CIGS OUTSIDE OF LIMITED NOCTURNAL LIFTING. GENERALLY...MFVR CIGS WILL BE MAINTAINED OVERNIGHT WITH POSSIBLE DIPS INTO IFR ARND AND THROUGH DAYBREAK ESP IN ISOL SHRA. THEN A LIFT INTO LOW VFR PROBABLE LATE MORNING. WINDS REMAIN NE/LY NON/MTNS WITH MODERATE GUSTS THROUGH THE OVERNIGHT AS P/GRAD LOOSENS. KAVL AND MTN VICINITY AIRPORTS WILL EXPERIENCE WS ISSUES LATE PERIOD AS LLVL JET SWINGS AROUND SFC TROF. A DECREASE IN CIG HEIGHTS TO MFVR/IFR IS ANTICIPATED AGAIN LATTER PERIOD ALL SITES. OUTLOOK...DEEP MOISTURE AND WIDESPREAD LIFT WILL LIKELY RESULT IN RESTRICTIVE CEILINGS AND VISIBILITY PERIODICALLY THRU SATURDAY. IN ADDITION...RAINFALL WILL BE MODERATE TO HEAVY AT TIMES THROUGH SATURDAY. CONFIDENCE TABLE... 05-11Z 11-17Z 17-23Z 23-00Z KCLT HIGH 93% HIGH 100% HIGH 100% HIGH 91% KGSP MED 78% MED 61% MED 78% MED 66% KAVL LOW 57% LOW 38% LOW 39% HIGH 91% KHKY LOW 57% HIGH 83% HIGH 100% HIGH 91% KGMU HIGH 85% HIGH 83% HIGH 100% HIGH 100% KAND HIGH 85% MED 72% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...JMP NEAR TERM...NED/SBK SHORT TERM...RWH LONG TERM...JMP AVIATION...SBK
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1146 PM CDT THU SEP 24 2015 .UPDATE... FOR 06Z AVIATION. .DISCUSSION... LATEST REGIONAL RADAR MOSAIC SHOWS LARGE AREA OF LIGHT RAIN CONTINUE TO SPREAD WESTWARD ACROSS THE APPALACHIANS INTO NORTHWEST GEORGIA AND EASTERN TENNESSEE. LATEST HRRR TIMES THIS LIGHT RAIN TO REACH THE PLATEAU COUNTIES AROUND 09Z OR SO...THEN SPREADING ACROSS MUCH OF THE REST OF THE CWA DURING THE DAY ON FRIDAY. CURRENT FORECAST HAS THIS ALL HANDLED AND NO CHANGES WERE MADE. AFTER ANOTHER MILD NIGHT TONIGHT...HIGHS TOMORROW WILL BE MUCH COOLER THAN SEEN RECENTLY DUE TO CLOUD COVER AND PRECIP...ESPECIALLY ON THE PLATEAU WHICH WILL LIKELY NOT MAKE IT OUT OF THE 60S. SHAMBURGER .AVIATION... 06Z TAF DISCUSSION. VFR LOOKS TO HOLD A BIT LONGER THIS EVENING FOR ALL TAF SITES BEFORE DROPPING CIGS TO IMPACT KCSV LATER THIS MORNING. MVFR CIGS SHOULD BE AT KCSV BY 12Z OR SO...THEN IFR CIGS BY THE AFTERNOON. MODELS ALSO HINTING AT LIFR CIGS BY MID TO LATE AFTERNOON AT KCSV. HAVE KBNA AND KCKV WITH MVFR CIGS BY THE AFTERNOON. RAIN CHANCES WILL MOVE IN WITH THE LOWER CIGS...AND MAY LOWER VIS TO MVFR AND EVEN IFR FOR THIS TAF PERIOD. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
105 AM EDT FRI SEP 25 2015 .SYNOPSIS... A COMPLEX AREA OF LOW PRESSURE ACROSS THE SOUTHEAST STATES WILL CONTINUE TO PUSH DEEP TROPICAL MOISTURE INTO THE APPALACHIANS AND MID ATLANTIC REGION INTO THE WEEKEND. THIS COMBINED WITH A STRONG WEDGE OF HIGH PRESSURE ALONG THE APPALACHIANS WILL LEAD TO WIDESPREAD RAINFALL UNDER GUSTY NORTHEAST WINDS AND COOL TEMPERATURES. WEAK HIGH PRESSURE SHOULD BUILD IN BRINGING SOMEWHAT DRIER AND WARMER WEATHER FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... AS OF 935 PM EDT THURSDAY... COVERAGE OF SHOWERS INCREASING OVER CENTRAL AND WESTERN NC...WITH POCKETS OF MODERATE RAIN. THE LATEST HRRR SHOWS THIS AREA OF PRECIP WELL...AND STARTS TO PROGRESS IT NWD INTO THE VIRGINIAS BETWEEN 10 PM AND 3 AM. THE FORECAST FOLLOWS THIS SCENARIO WHICH IS SOMEWHAT CLOSE TO THE EARLIER FORECAST. STILL LOOKS LIKE A GENEROUS QUARTER TO HALF INCH BY MORNING FROM THE NC/VA BORDER SWD...WITH LITTLE TO NO MEASURABLE OVER THE ALLEGHANYS. PWATS HAVE RISEN FROM .7 TO .89 HERE AT RNK PER SOUNDING FROM 8 AM TODAY TIL 8 PM...WHILE GSO HAS GONE FROM 0.74 TO 1.52 DURING THIS TIME. SITUATION WET FOR MORNING COMMUTE SO TRAVELER SHOULD WATCH FOR PONDING ON THE ROADS...MAINLY ACROSS INTERSTATE 81 SOUTHWEST OF CHRISTIANSBURG/BLACKSBURG...I-77 SOUTH OF WYTHEVILLE ALONG HIGHWAY 58 IN VIRGINIA...AND POINTS SOUTH. TEMPERATURES OVERNIGHT WITH MORE CLOUDS WILL DROP SOME ESPECIALLY ONCE RAIN HITS AND WET BULBS TO THE MID TO UPPER 50S. PREVIOUS AFTERNOON DISCUSSION... THE TROPICAL PLUME OF MOISTURE IS EVIDENT ON WV LOOPS THIS EVENING FROM THE SC/NC COAST NW INTO WRN NC. A GOOD AMOUNT OF RAIN IS ON THE WAY FOR THE APPALACHIANS AND CENTRAL MID ATLANTIC REGION. THE OVERALL SCENARIO ADVERTISED OVER THE PAST FEW DAYS IS STARTING TO UNFOLD AS DEVELOPING LOW PRESSURE ALONG THE SOUTHEAST ATLANTIC COAST IS THROWING DEEP TROPICAL MOISTURE IN OUR DIRECTION...CLEARLY EVIDENT IN WATER VAPOR IMAGERY. THIS WILL LEAD TO STEADILY THICKENING CLOUDS WITH PRECIPITATION SPREADING INTO THE REGION FROM THE SOUTH OVERNIGHT...MARKING THE START OF A PERIOD OF RAIN THAT WILL LAST INTO THE WEEKEND. WHILE THERE WILL LIKELY BE ENHANCEMENT OF PRECIPITATION ALONG THE BLUE RIDGE...WATER LEVELS ARE STILL RUNNING LOW FROM OUR RECENT DRY SPELL AND PRECIPITATION RATES DO NOT APPEAR THAT THEY WILL BE HIGH ENOUGH TO CAUSE A FLASH FLOOD CONCERN AT THIS TIME. WITH THIS IN MIND...THE AREA SEEMS WELL SITUATED TO ABSORB A LONG DURATION HEAVY RAINFALL EVENT WITHOUT CAUSING SIGNIFICANT PROBLEMS SO NO FLOOD/FLASH FLOOD WATCHES WILL BE ISSUED WITH THIS PACKAGE. AS ALWAYS...THE NEED FOR ANY FLASH/FLOOD WATCHES WILL CONTINUALLY BE MONITORED AND MAY BE ISSUED AT A LATER TIME IF CONDITIONS WARRANT. EXPECT THAT THE CLOUDS AND RAIN WILL KEEP TEMPERATURES QUITE COOL FOR TOMORROW AND WILL GO ON THE COOL SIDE OF GUIDANCE WITH MID/UPPER 60S EAST OF THE RIDGE AND LOW/MID 60S EAST. THE TIGHTENING PRESSURE GRADIENT BETWEEN THE WEDGE OF HIGH PRESSURE ALONG THE COASTAL PLAIN AND THE DEVELOPING LOW WILL MAKE FOR A STIFF NORTHEAST BREEZE OVERNIGHT AND THROUGH TOMORROW. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... AS OF 305 PM EDT THURSDAY... CLOSED UPPER LOW DRIFTS NORTH THROUGH THE TENNESSEE VALLEY THEN WEAKENS FRIDAY NIGHT AND SATURDAY. MODELS STILL ADVERTISING STRING EARLY FLOW OF ATLANTIC MOISTURE INTO THE REGION WITH 850 MB WINDS FROM THE EAST AT SPEEDS AS HIGH AS 45 KNOTS FRIDAY NIGHT INTO SUNDAY MORNING. MODELS SHOW A WELL DEFINED IN-SITU WEDGE WITH LITTLE TO NO INSTABILITY...EVEN ELEVATED ABOVE THE INVERSION. DEPTH OF WEDGE IS FORECAST TO BE 3000 TO 8000 FEET DEEP ACCORDING TO THE BUFKIT FROM THE GFS AND NAM. MUCH OF THE DEEP EASTERLY FLOW WILL OVERRUN THE COLD AIR IN THE WEDGE...WELL ABOVE ANY HEIGHTS THAT WOULD ADD TO UPSLOPE ENHANCEMENT. SO AXIS OF MAXIMUM PRECIPITATION MAY BE IN THE PIEDMONT...ON THE EASTERN EDGE OF THE COLD AIR DOME. BUT THERE WILL STILL BE A SECONDARY MAXIMUM ON THE EAST SLOPES OF THE BLUE RIDGE. WEDGE...CLOUDS AND PRECIPITATION WILL RESULT IN ONLY A SMALL RISE IN TEMPERATURES DURING THE DAY. HAVE LOWERED MAXIMUM TEMPERATURES FOR SATURDAY AND SUNDAY CLOSE TO ECMWF VALUES. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AS OF 305 PM EDT THURSDAY... SPREAD IN MODEL SOLUTIONS GROWS LARGER IN THIS TIME RANGE...ESPECIALLY FROM TUESDAY NIGHT THROUGH THURSDAY. SUNDAY NIGHT THROUGH TUESDAY MODELS SHOW A CLOSED UPPER LOW OVER TEXAS WITH RIDGING OVER THE WESTERN ATLANTIC. COASTAL SURFACE TROFFIING AND WEDGE OF HIGH PRESSURE OVER THE FORECAST AREA PERSISTS INTO MONDAY SO WILL MAINTAIN PROBABILITY OF PRECIPITATION DUE TO THE CONTINUED INFLOW OF MOISTURE OFF THE ATLANTIC. APPEARS BEST FORCING WILL BE CONFINED TO THE CLOSED LOW AND GULF COAST REGION AND MUCH FARTHER NORTH ALONG A COLD FRONT. ECMWF SHOWING DECENT 500 MB HEIGHT FALLS OVER NEW ENGLAND AND THE MID ATLANTIC REGION ON TUESDAY AND WEDNESDAY...WITH TROFFING CONTINUING TO DEVELOP OVER THE EASTERN UNITED STATES THROUGH THURSDAY. A WEAKENING COLD FRONT MOVES SOUTH ACROSS THE MID ATLANTIC REGION ON WEDNESDAY AND WEDNESDAY NIGHT FOLLOWED BY HIGH PRESSURE AND COOLER AIR ON THURSDAY. WPC WAS FAVORING A BLEND OF THE GFS/ECMWF. NOT MUCH MOISTURE LEFT ALONG THE FRONT BY WEDNESDAY SO WILL HAVE DAY 5 TO DAY 7 OF THE FORECAST DRY. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 100 AM EDT FRIDAY... FLYING CONDITIONS WILL CONTINUE TO DETERIORATE OVERNIGHT AS DEEP MOISTURE ALONG WITH A BAND OF LIGHT TO MODERATE RAIN SHIFTS SLOWLY NORTH THROUGH DAYBREAK. THIS SHOULD HELP LOWER CIGS INITIALLY INTO MVFR LEVELS ALONG THE KBLF-KBCB-KDAN CORRIDOR OVERNIGHT AND POINTS TO THE NORTH AND EAST EARLY FRIDAY. PRECIP MENTIONED IN THE TAFS FIRST AT DANVILLE SHORTLY AFTER MIDNIGHT AND THEN REMAINING LOCATIONS BETWEEN 06-12Z AND LEWISBURG BY 14Z. EXPECT CEILINGS TO FINALLY DROP THROUGH MVFR EARLY FRIDAY AS THINGS SATURATE FURTHER AND EVENTUALLY IFR DURING THE DAY ON FRIDAY. KBLF MAY TREND IN AND OUT OF LIFR AS WELL AS KLWB GIVEN DOWNSLOPE FLOW...OTHERWISE APPEARS LOW IFR CIGS IN ORDER ALONG WITH MOUNTAIN OBSCURATIONS FRIDAY INTO FRIDAY NIGHT. LOW LEVEL WINDS WILL REMAIN OUT OF THE NORTHEAST...AND GUST 15-30 KTS AT TIMES FROM LATER TONIGHT THROUGH FRIDAY NIGHT. EXTENDED AVIATION DISCUSSION... LOW PRESSURE WILL LINGER ALONG THE SOUTHEAST ATLANTIC COAST THIS WEEKEND. FORECAST MODELS AGREE THAT PERIODS OF RAIN WILL PERSIST THIS WEEKEND BUT DISAGREE SOMEWHAT ON INTENSITY. REGARDLESS OF THE AMOUNT OF RAIN...A STRONG EASTERLY FLOW WILL CONTINUE THROUGH SUNDAY AND SUB VFR CEILINGS/VSBYS SHOULD BE EXPECTED. THE WEDGE SHOULD WEAKEN ON MONDAY BRINGING IN DRIER AIR AND RETURN CONDITIONS TO VFR. HOWEVER ANOTHER STORM SYSTEM LOOKS TO ARRIVE MID WEEK BRINGING ANOTHER ROUND OF PRECIP AND SUB VFR CEILINGS/VSBYS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/MBS NEAR TERM...MBS/WP SHORT TERM...AMS LONG TERM...AMS AVIATION...CF/JH/MBS
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
403 AM MDT FRI SEP 25 2015 .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 345 AM MDT FRI SEP 25 2015 A QUIET WEATHER PERIOD WILL CONTINUE OVER THE NEXT SEVERAL DAYS WITH UPPER-LEVEL RIDGING IN PLACE. A MOIST LOW-LEVEL AIR MASS REMAINS IN PLACE WITH WIDESPREAD SURFACE DEW POINTS IN THE 40S/50S. LIGHT WINDS AND CLEAR SKIES HAVE ONCE AGAIN ALLOWED PATCHY FOG TO DEVELOP ACROSS THE NE PANHANDLE AND PLATTE RIVER VALLEY EXTENDING INTO SOUTHEASTERN WY. STRONG SUBSIDENCE SUGGESTS SUNNY SKIES WILL PREVAIL BEYOND ABOUT 15Z WHEN THE HRRR HINTS AT FOG STARTING TO ERODE. WE COULD VERY WELL SEE THIS AGAIN TONIGHT AS THE NAM SHOWS A RATHER ROBUST INCREASE IN BOUNDARY LAYER MOISTURE AFTER 03Z SAT VIA MOIST SOUTHEASTERLY LOW- LEVEL FLOW. INHIBITING FACTOR FOR FOG WOULD BE STRONGER WINDS OWING TO A HIGHER SURFACE PRESSURE GRADIENT THAN WE ARE SEEING ATTM...BUT NAM/GFS BUFKIT SOUNDINGS BOTH OFFER ENOUGH SUPPORT TO ADD PATCHY FOG TO THE GRIDS. IT STILL LOOKS VERY WARM THIS WEEKEND WITH H7 TEMPS IN THE +13 TO +15 DEG C RANGE ACROSS MOST OF THE CWA ON SAT/SUN. EXPECT TO SEE WIDESPREAD HIGHS IN THE 85-95 DEG F RANGE...WHICH MAY BE NEAR RECORD AT SOME SITES. AREAS ALONG AND WEST OF THE LARAMIE RANGE WILL SEE AFTERNOON HUMIDITIES BELOW 15 PERCENT EACH AFTERNOON...BUT MID- LEVEL FLOW IS NOT PARTICULARLY STRONG WITH A RIDGE AXIS PARKED OVER THE CENTRAL ROCKIES. STRONG MIXING WILL ALMOST UNDOUBTEDLY YIELD A FEW GUSTS AROUND 20-25 MPH...BUT OPTED NOT TO ISSUE ANY FIRE WEATHER HIGHLIGHTS AS ANY POTENTIAL FOR RED FLAG CONDITIONS WILL BE MARGINAL AT BEST. .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 345 AM MDT FRI SEP 25 2015 MONDAY WILL LIKELY BE THE WARMEST DAY OF THE EXTENDED PERIOD WITH STRONG RIDGING ALOFT AND 700MB TEMPS AROUND 12C. A WEAK COLD FRONT WILL MOVE ACROSS THE PLAINS ON MON NIGHT WITH WINDS BECOME EASTERLY BY TUES. THE GFS CONTINUES TO BE MORE BULLISH WITH QPF ON TUES AND TUES NIGHT AS UPPER LEVEL DISTURBANCES INTERACT WITH THE LLVL UPSLOPE. THE ECMWF SHOWS LOW STRATUS TO THE EAST OF THE LARAMIE RANGE WITH DRIZZLE/LIGHT RAIN SHOWERS...HOWEVER DEEP LAYER UPWARD MOTION IS LACKING. HAVE 20 PERCENT POPS FROM TUES INTO TUES NIGHT WITH THE MODEL UNCERTAINTY STILL HIGH. THERE WILL BE A COOLDOWN FOR TUES BEHIND THE FRONT. THE ECMWF SHOWS QUICKLY RISING HEIGHTS/TEMPS BY WED WHEREAS THE GFS HAS THE UPPER TROUGH AXIS MOVING OVERHEAD. WINDS THROUGHOUT THE LONG TERM WILL BE QUITE LIGHT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1148 PM MDT THU SEP 24 2015 IFR CONDITIONS WILL BE POSSIBLE ACROSS THE NEBRASKA PANHANDLE THROUGH MID MORNING AS LIGHT WINDS AND A VERY MOIST AIRMASS ARE CONDUCIVE FOR AREAS OF LIFR VIS AND FOG. VFR CONDITIONS WILL PREVAIL OVER SOUTHEAST WY. WINDS WILL BE LIGHT THROUGH THE TAF PERIOD. && .FIRE WEATHER... ISSUED AT 345 AM MDT FRI SEP 25 2015 WARM AND DRY WEATHER WILL CONTINUE THROUGH THE WEEKEND. AREAS ALONG AND WEST OF THE LARAMIE RANGE WILL LIKELY SEE MINIMUM HUMIDITIES AT OR BELOW 15 PERCENT EACH AFTERNOON THROUGH SUN. ELEVATED CONDITIONS ARE LIKELY OVER THE WEEKEND AS WIND GUSTS COULD APPROACH 20-25 MPH AT TIMES. NO FIRE WEATHER HIGHLIGHTS ARE EXPECTED AT THIS TIME AS WINDS ARE EXPECTED TO REMAIN JUST BELOW CRITICAL THRESHOLDS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...CLH LONG TERM...ZF AVIATION...ZF FIRE WEATHER...CLH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1202 AM MDT FRI SEP 25 2015 .UPDATE... ISSUED AT 910 PM MDT THU SEP 24 2015 LATEST 11-3.9U SATELLITE IMAGERY SHOWING A WIDE BAND OF LOW CLOUDS INCHING WESTWARD FROM WESTERN NEBRASKA TOWARDS THE PANHANDLE. LATEST HRRR GUIDANCE SHOWING FOG COULD BE WIDESPREAD ACROSS THE PANHANDLE AFTER MIDNIGHT. WENT AHEAD AND EXPANDED FOG TO COVER MUCH OF THE PANHANDLE TO THE WYOMING STATE LINE. UPDATES HAVE BEEN SENT. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 200 PM MDT THU SEP 24 2015 DRY AND WARM WEATHER WILL HOLD OVER THE CWA THROUGH SATURDAY COMPLEMENTS OF AN UPPER RIDGE THAT WILL BE OVER THE CWA THROUGH MOST OF THE PERIOD. THE RIDGE WILL WEAKEN SOME LATER SATURDAY AS SHORTWAVE ENERGY MOVES ACROSS SOUTHERN CANADA BUT THATS ABOUT THE ONLY WEATHER FEATURE OF NOTE OVERALL. SOME MAINLY VALLEY FOG WILL BE POSSIBLE AGAIN LATER TONIGHT INTO FRIDAY MORNING OVER THE NEB PANHANDLE AS WEAK EASTERLY FLOW MAY ADVECT IN SUFFICIENT MOISTURE UNDER CLEAR SKIES. TEMPERATURES WILL REMAIN ABOVE SEASONAL NORMS BOTH DAYS. .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 200 PM MDT THU SEP 24 2015 12Z MEDIUM RANGE MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE RIDGE AXIS FROM THE UPPER MIDWEST TO DESERT SOUTHWEST SLOWLY DRIFTING SOUTH AS SHORTWAVE ENERGY TRACKS EAST FROM THE PACIFIC NORTHWEST ACROSS THE NORTHERN TIER OF THE CONUS THROUGH MONDAY. THE GFS SHOWS A VORT LOBE EXTENDING FROM IA WESTWARD ACROSS SOUTHERN WY MONDAY NIGHT THROUGH TUESDAY...PULLING A PACIFIC FRONT ACROSS THE CWA. THE ECMWF MAINTAINS A WEAK RIDGE ALOFT WITH A WEAKER SHORTWAVE FURTHER NORTH. BOTH MODELS PRODUCE WIDELY SCATTERED CONVECTION...MAINLY IN THE VICINITY OF THE MOUNTAINS AND NORTHEAST CWA. IT WILL BE BREEZY EACH AFTERNOON WEST OF THE LARAMIE RANGE...WITH LIGHTER WINDS ELSEWHERE. IT WILL BE QUITE WARM SUNDAY AND MONDAY WITH HIGHS IN THE 70S AND 80S...COOL 5 TO 10 DEGREES TUESDAY...FOLLOWED BY SLIGHT WARMING WEDNESDAY AND THURSDAY. LOWS WILL RANGE FROM THE 40S TO LOW 50S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1148 PM MDT THU SEP 24 2015 IFR CONDITIONS WILL BE POSSIBLE ACROSS THE NEBRASKA PANHANDLE THROUGH MID MORNING AS LIGHT WINDS AND A VERY MOIST AIRMASS ARE CONDUCIVE FOR AREAS OF LIFR VIS AND FOG. VFR CONDITIONS WILL PREVAIL OVER SOUTHEAST WY. WINDS WILL BE LIGHT THROUGH THE TAF PERIOD. && .FIRE WEATHER... ISSUED AT 200 PM MDT THU SEP 24 2015 DRY AND WARM CONDITIONS ARE EXPECTED TO CONTINUE INTO EARLY NEXT WEEK. SOME ELEVATED CONCERNS IN THE AFTERNOONS OVER WESTERN SECTIONS WHERE WINDS SHOULD COME UP A BIT BUT NOT LOOKING TOO STRONG AT THIS TIME. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...GCC SHORT TERM...RE LONG TERM...MAJ AVIATION...ZF FIRE WEATHER...RE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1100 AM CDT FRI SEP 25 2015 .UPDATE... ISSUED AT 1100 AM CDT FRI SEP 25 2015 THIS UPDATE TO EXPIRE THE DENSE FOG ADVISORY. UPDATE ISSUED AT 848 AM CDT FRI SEP 25 2015 WEBCAMS AND SURFACE OBSERVATIONS SHOW DENSE FOG CONTINUES IN MORTON COUNTY INCLUDING MANDAN...AND THE AREA EAST OF THE MISSOURI RIVER THROUGH THE JAMES RIVER VALLEY AND NORTH TO BOTTINEAU COUNTY. WILL KEEP THE ADVISORY GOING THROUGH 16Z. OTHERWISE USED SAT DATA TO MANUALLY ADJUST SKY CONDITION. STRATUS/FOG KEEPING HOURLY TEMPS COOL ACROSS THE JAMES RIVER VALLEY THIS MORNING. SHOULD SLOWLY CATCH UP WITH HIGH FORECAST AS CLOUDS DISSIPATE. UPDATE ISSUED AT 628 AM CDT FRI SEP 25 2015 BASED ON WEBCAMS AND SATELLITE THROUGH 1115 UTC...EXPANDED THE DENSE FOG ADVISORY INTO SIOUX...GRANT...MORTON...OLIVER AND MCLEAN COUNTIES THROUGH 16 UTC THIS MORNING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 243 AM CDT FRI SEP 25 2015 CURRENTLY...HIGH PRESSURE WAS CENTERED OVER HUDSON BAY...WITH A TROUGH OF LOW PRESSURE ALONG THE LEE OF THE ROCKIES. ANOTHER SURFACE LOW WAS OVER EASTERN NEBRASKA. LOW LEVEL MOISTURE MAINLY ASSOCIATED WITH THE LOW OVER NEBRASKA HAD SPREAD NORTHWARD INTO THE NORTHERN PLAINS. LOW CLOUDS AND FOG WAS COMMON FROM WISCONSIN AND MINNESOTA INTO THE EASTERN DAKOTAS AND SOUTHERN MANITOBA. THE LATEST ITERATIONS OF THE SHORT TERM HRRR MODEL CONTINUE TO INDICATE LOW CLOUDS AND FOG EXPANDING ACROSS CENTRAL AND EASTERN NORTH DAKOTA...MAINLY EAST OF THE MISSOURI RIVER IN SOUTH CENTRAL NORTH DAKOTA AND EAST OF MINOT/BOTTINEAU IN THE NORTH CENTRAL. ROLLA AND JAMESTOWN STATIONS HAVE REPORTED 1/4 MILE VISIBILITY...AND EXPECT THOSE CONDITIONS TO EXPAND WESTWARD. THUS WILL ISSUE A DENSE FOG ADVISORY ALONG AND EAST OF A LINE FROM BOTTINEAU TO BISMARCK TO THE LINTON AND STRASBURG AREAS. THIS INCLUDES THE TURTLE MOUNTAINS AND THE JAMES RIVER VALLEY. THE HRRR INDICATES THAT VISIBILITIES SHOULD IMPROVE QUICKLY AROUND 10AM-11AM...SO WILL HAVE THE ADVISORY IN EFFECT UNTIL 11 AM CDT. SOUTHERLY WINDS SHOULD INCREASE DURING THE LATE MORNING AND HELP MIX THE SURFACE WITH THE BOUNDARY LAYER. EXPECT IMPROVING CONDITIONS THIS AFTERNOON WITH PARTLY TO MOSTLY SUNNY SKIES AND HIGHS IN THE MID-UPPER 70S CENTRAL TO LOWER 80S WEST. SOUTHERLY WINDS REMAIN TONIGHT AHEAD OF AN APPROACHING SURFACE TROUGH...AND MODELS HINT AT RETURN OF LOW CLOUDS AND POSSIBLE FOG TO THE AREA. FOR NOW HAVE INCREASED THE FORECAST SKY COVER A BIT...AND WILL SEE HOW THE NEXT SET OF MODELS HANDLES THE LOW LEVEL MOISTURE FIELD. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 243 AM CDT FRI SEP 25 2015 A WARM UP INTO SATURDAY FOLLOWED BY A COOLING TREND EARLY NEXT WEEK HIGHLIGHTS THE EXTENDED FORECAST. THE 24/12 UTC NAEFS PERCENTILES DEPICT 850MB TEMPERATURES IN THE 99TH TO NEAR MAXIMUM PERCENTILES ACROSS SOUTHEAST MONTANA INTO SOUTHWEST NORTH DAKOTA SATURDAY AFTERNOON AHEAD OF A STRONG COLD FRONT FORECAST TO OVERTAKE THE AREA SATURDAY NIGHT INTO SUNDAY. THUS...INCREASED HIGHS INTO THE LOWER 90S WEST OF THE MISSOURI RIVER FOR SATURDAY...WHICH IS ABOVE THE 00 UTC GUIDANCE CONSENSUS. THEREAFTER...TEMPERATURES DECLINE AS THE SATURDAY UPPER LEVEL RIDGE BREAKS DOWN AND COOL HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE REGION MONDAY INTO TUESDAY. WIDESPREAD HIGHS IN THE 60S...AND POSSIBLY THE 50S ARE EXPECTED. MORNING FROST WILL BE POSSIBLE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 628 AM CDT FRI SEP 25 2015 AT 6 AM CDT...FOG HAD EXPANDED OVER MUCH OF CENTRAL NORTH DAKOTA. DENSE FOG WITH VISIBILITY 1/4SM OR LESS EXPECTED TO CONTINUE AT KJMS AND KBIS UNTIL AROUND 15Z-16Z. KMOT/KDIK/KISN HAVE FOG IN TEMPO GROUPS UNTIL AROUND 15Z-16Z. BECOMING VFR ALL TAF SITES AFT 16Z WITH INCREASING SOUTH WINDS. THERE IS THE POTENTIAL RETURNING FOG/LOW CLOUDS AFTER SUNSET FRIDAY EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...JV LONG TERM...AYD AVIATION...JV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
853 AM CDT FRI SEP 25 2015 .UPDATE... ISSUED AT 848 AM CDT FRI SEP 25 2015 WEBCAMS AND SURFACE OBSERVATIONS SHOW DENSE FOG CONTINUES IN MORTON COUNTY INCLUDING MANDAN...AND THE AREA EAST OF THE MISSOURI RIVER THROUGH THE JAMES RIVER VALLEY AND NORTH TO BOTTINEAU COUNTY. WILL KEEP THE ADVISORY GOING THROUGH 16Z. OTHERWISE USED SAT DATA TO MANUALLY ADJUST SKY CONDITION. STRATUS/FOG KEEPING HOURLY TEMPS COOL ACROSS THE JAMES RIVER VALLEY THIS MORNING. SHOULD SLOWLY CATCH UP WITH HIGH FORECAST AS CLOUDS DISSIPATE. UPDATE ISSUED AT 628 AM CDT FRI SEP 25 2015 BASED ON WEBCAMS AND SATELLITE THROUGH 1115 UTC...EXPANDED THE DENSE FOG ADVISORY INTO SIOUX...GRANT...MORTON...OLIVER AND MCLEAN COUNTIES THROUGH 16 UTC THIS MORNING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 243 AM CDT FRI SEP 25 2015 CURRENTLY...HIGH PRESSURE WAS CENTERED OVER HUDSON BAY...WITH A TROUGH OF LOW PRESSURE ALONG THE LEE OF THE ROCKIES. ANOTHER SURFACE LOW WAS OVER EASTERN NEBRASKA. LOW LEVEL MOISTURE MAINLY ASSOCIATED WITH THE LOW OVER NEBRASKA HAD SPREAD NORTHWARD INTO THE NORTHERN PLAINS. LOW CLOUDS AND FOG WAS COMMON FROM WISCONSIN AND MINNESOTA INTO THE EASTERN DAKOTAS AND SOUTHERN MANITOBA. THE LATEST ITERATIONS OF THE SHORT TERM HRRR MODEL CONTINUE TO INDICATE LOW CLOUDS AND FOG EXPANDING ACROSS CENTRAL AND EASTERN NORTH DAKOTA...MAINLY EAST OF THE MISSOURI RIVER IN SOUTH CENTRAL NORTH DAKOTA AND EAST OF MINOT/BOTTINEAU IN THE NORTH CENTRAL. ROLLA AND JAMESTOWN STATIONS HAVE REPORTED 1/4 MILE VISIBILITY...AND EXPECT THOSE CONDITIONS TO EXPAND WESTWARD. THUS WILL ISSUE A DENSE FOG ADVISORY ALONG AND EAST OF A LINE FROM BOTTINEAU TO BISMARCK TO THE LINTON AND STRASBURG AREAS. THIS INCLUDES THE TURTLE MOUNTAINS AND THE JAMES RIVER VALLEY. THE HRRR INDICATES THAT VISIBILITIES SHOULD IMPROVE QUICKLY AROUND 10AM-11AM...SO WILL HAVE THE ADVISORY IN EFFECT UNTIL 11 AM CDT. SOUTHERLY WINDS SHOULD INCREASE DURING THE LATE MORNING AND HELP MIX THE SURFACE WITH THE BOUNDARY LAYER. EXPECT IMPROVING CONDITIONS THIS AFTERNOON WITH PARTLY TO MOSTLY SUNNY SKIES AND HIGHS IN THE MID-UPPER 70S CENTRAL TO LOWER 80S WEST. SOUTHERLY WINDS REMAIN TONIGHT AHEAD OF AN APPROACHING SURFACE TROUGH...AND MODELS HINT AT RETURN OF LOW CLOUDS AND POSSIBLE FOG TO THE AREA. FOR NOW HAVE INCREASED THE FORECAST SKY COVER A BIT...AND WILL SEE HOW THE NEXT SET OF MODELS HANDLES THE LOW LEVEL MOISTURE FIELD. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 243 AM CDT FRI SEP 25 2015 A WARM UP INTO SATURDAY FOLLOWED BY A COOLING TREND EARLY NEXT WEEK HIGHLIGHTS THE EXTENDED FORECAST. THE 24/12 UTC NAEFS PERCENTILES DEPICT 850MB TEMPERATURES IN THE 99TH TO NEAR MAXIMUM PERCENTILES ACROSS SOUTHEAST MONTANA INTO SOUTHWEST NORTH DAKOTA SATURDAY AFTERNOON AHEAD OF A STRONG COLD FRONT FORECAST TO OVERTAKE THE AREA SATURDAY NIGHT INTO SUNDAY. THUS...INCREASED HIGHS INTO THE LOWER 90S WEST OF THE MISSOURI RIVER FOR SATURDAY...WHICH IS ABOVE THE 00 UTC GUIDANCE CONSENSUS. THEREAFTER...TEMPERATURES DECLINE AS THE SATURDAY UPPER LEVEL RIDGE BREAKS DOWN AND COOL HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE REGION MONDAY INTO TUESDAY. WIDESPREAD HIGHS IN THE 60S...AND POSSIBLY THE 50S ARE EXPECTED. MORNING FROST WILL BE POSSIBLE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 628 AM CDT FRI SEP 25 2015 AT 6 AM CDT...FOG HAD EXPANDED OVER MUCH OF CENTRAL NORTH DAKOTA. DENSE FOG WITH VISIBILITY 1/4SM OR LESS EXPECTED TO CONTINUE AT KJMS AND KBIS UNTIL AROUND 15Z-16Z. KMOT/KDIK/KISN HAVE FOG IN TEMPO GROUPS UNTIL AROUND 15Z-16Z. BECOMING VFR ALL TAF SITES AFT 16Z WITH INCREASING SOUTH WINDS. THERE IS THE POTENTIAL RETURNING FOG/LOW CLOUDS AFTER SUNSET FRIDAY EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 11 AM CDT /10 AM MDT/ THIS MORNING FOR NDZ004-005-012-013-020>023-025-034>037-042-045>048-050-051. && $$ UPDATE...WAA SHORT TERM...JV LONG TERM...AYD AVIATION...JV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
631 AM CDT FRI SEP 25 2015 .UPDATE... ISSUED AT 628 AM CDT FRI SEP 25 2015 BASED ON WEBCAMS AND SATELLITE THROUGH 1115 UTC...EXPANDED THE DENSE FOG ADVISORY INTO SIOUX...GRANT...MORTON...OLIVER AND MCLEAN COUNTIES THROUGH 16 UTC THIS MORNING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 243 AM CDT FRI SEP 25 2015 CURRENTLY...HIGH PRESSURE WAS CENTERED OVER HUDSON BAY...WITH A TROUGH OF LOW PRESSURE ALONG THE LEE OF THE ROCKIES. ANOTHER SURFACE LOW WAS OVER EASTERN NEBRASKA. LOW LEVEL MOISTURE MAINLY ASSOCIATED WITH THE LOW OVER NEBRASKA HAD SPREAD NORTHWARD INTO THE NORTHERN PLAINS. LOW CLOUDS AND FOG WAS COMMON FROM WISCONSIN AND MINNESOTA INTO THE EASTERN DAKOTAS AND SOUTHERN MANITOBA. THE LATEST ITERATIONS OF THE SHORT TERM HRRR MODEL CONTINUE TO INDICATE LOW CLOUDS AND FOG EXPANDING ACROSS CENTRAL AND EASTERN NORTH DAKOTA...MAINLY EAST OF THE MISSOURI RIVER IN SOUTH CENTRAL NORTH DAKOTA AND EAST OF MINOT/BOTTINEAU IN THE NORTH CENTRAL. ROLLA AND JAMESTOWN STATIONS HAVE REPORTED 1/4 MILE VISIBILITY...AND EXPECT THOSE CONDITIONS TO EXPAND WESTWARD. THUS WILL ISSUE A DENSE FOG ADVISORY ALONG AND EAST OF A LINE FROM BOTTINEAU TO BISMARCK TO THE LINTON AND STRASBURG AREAS. THIS INCLUDES THE TURTLE MOUNTAINS AND THE JAMES RIVER VALLEY. THE HRRR INDICATES THAT VISIBILITIES SHOULD IMPROVE QUICKLY AROUND 10AM-11AM...SO WILL HAVE THE ADVISORY IN EFFECT UNTIL 11 AM CDT. SOUTHERLY WINDS SHOULD INCREASE DURING THE LATE MORNING AND HELP MIX THE SURFACE WITH THE BOUNDARY LAYER. EXPECT IMPROVING CONDITIONS THIS AFTERNOON WITH PARTLY TO MOSTLY SUNNY SKIES AND HIGHS IN THE MID-UPPER 70S CENTRAL TO LOWER 80S WEST. SOUTHERLY WINDS REMAIN TONIGHT AHEAD OF AN APPROACHING SURFACE TROUGH...AND MODELS HINT AT RETURN OF LOW CLOUDS AND POSSIBLE FOG TO THE AREA. FOR NOW HAVE INCREASED THE FORECAST SKY COVER A BIT...AND WILL SEE HOW THE NEXT SET OF MODELS HANDLES THE LOW LEVEL MOISTURE FIELD. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 243 AM CDT FRI SEP 25 2015 A WARM UP INTO SATURDAY FOLLOWED BY A COOLING TREND EARLY NEXT WEEK HIGHLIGHTS THE EXTENDED FORECAST. THE 24/12 UTC NAEFS PERCENTILES DEPICT 850MB TEMPERATURES IN THE 99TH TO NEAR MAXIMUM PERCENTILES ACROSS SOUTHEAST MONTANA INTO SOUTHWEST NORTH DAKOTA SATURDAY AFTERNOON AHEAD OF A STRONG COLD FRONT FORECAST TO OVERTAKE THE AREA SATURDAY NIGHT INTO SUNDAY. THUS...INCREASED HIGHS INTO THE LOWER 90S WEST OF THE MISSOURI RIVER FOR SATURDAY...WHICH IS ABOVE THE 00 UTC GUIDANCE CONSENSUS. THEREAFTER...TEMPERATURES DECLINE AS THE SATURDAY UPPER LEVEL RIDGE BREAKS DOWN AND COOL HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE REGION MONDAY INTO TUESDAY. WIDESPREAD HIGHS IN THE 60S...AND POSSIBLY THE 50S ARE EXPECTED. MORNING FROST WILL BE POSSIBLE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 628 AM CDT FRI SEP 25 2015 AT 6 AM CDT...FOG HAD EXPANDED OVER MUCH OF CENTRAL NORTH DAKOTA. DENSE FOG WITH VISIBILITY 1/4SM OR LESS EXPECTED TO CONTINUE AT KJMS AND KBIS UNTIL AROUND 15Z-16Z. KMOT/KDIK/KISN HAVE FOG IN TEMPO GROUPS UNTIL AROUND 15Z-16Z. BECOMING VFR ALL TAF SITES AFT 16Z WITH INCREASING SOUTH WINDS. THERE IS THE POTENTIAL RETURNING FOG/LOW CLOUDS AFTER SUNSET FRIDAY EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 11 AM CDT /10 AM MDT/ THIS MORNING FOR NDZ004-005-012-013-020>023-025-034>037-042-045>048-050-051. && $$ UPDATE...AYD SHORT TERM...JV LONG TERM...AYD AVIATION...JV
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1046 AM EDT FRI SEP 25 2015 .SYNOPSIS... AN AREA OF LOW PRESSURE NEAR THE ATLANTIC COASTLINE WILL FEED MOISTURE-RICH AIR INTO THE REGION THROUGH MOST OF THE WEEKEND... RESULTING IN A LENGTHY STRETCH OF WIDESPREAD LIGHT TO MODERATE RAINFALL. DRIER CONDITIONS WILL PREVAIL HEADING INTO LATE SUNDAY AND EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 AM...STILL EXPECT WIDESPREAD RAIN AND DRIZZLE THRU THE DAY AS ISENTROPIC UPGLIDE AND ELY UPSLOPE LOW LEVEL FLOW CONTINUE ACROSS THE AREA. AN AREA OF HEAVIER RAINFALL OUTSIDE OF THE MTNS WILL MOVE NORTHWARD ACROSS THE CWFA TODAY...WHILE OFF AN ON HEAVIER RAINFALL CONTINUES ACROSS THE BLUE RIDGE AND MTNS. THAT SAID... PRECIP RATES DO NOT LOOK TO BE HIGH ENUF FOR WIDESPREAD FLOODING... BUT ISOLATED AREAS ARE POSSIBLE...ESPECIALLY IF ANY OF THE ELEVATED INSTABILITY COULD BE TAPPED INCREASING RATES. BREEZY NELY WINDS AND LOW CLOUDS...ALONG WITH THE RAIN AND DRIZZLE...WILL KEEP HIGHS BELOW NORMAL TODAY...WHICH HAS ALREADY BEEN ACCOUNTED FOR. 0630 AM UPDATE...NO MAJOR CHANGES NEEDED TO THE FCST. PRECIP SHIELD REMAINS FAIRLY WIDESPREAD. SOME CONVEC STREETS NOTED OVER THE MIDLANDS WITH DRY AIR ALOFT MIXING DOWN. THIS WILL LOWER POP POTENTIAL ACROSS THE SRN ZONES WITH SOME FILL-IN POSSIBLE AS MLVL Q/CONVG CROSSES OVERHEAD. THUS...WILL LEAVE POP GRADIENT AS IS IN THE GRIDS. RAINFALL REACHING THE ESCARPMENT IS NOT ENTIRELY ANCHORED AS LLVL FLOW REMAINS NE/LY BELOW 4 KFT. UPSLOPE ENHANCEMENT WILL BECOME MORE FAVORABLE THROUGH MID DAY. VERY GOOD MOISTURE FLUX ALIGNED IN DEEP ATL PWAT PLUME CONTINUES ACROSS THE FA THIS MORNING. HEAVIER RAINFALL RATES HAVE BEEN MAINTAINED SOUTH WITH THE UPSLOPE REGIONS REMAINING IN A RELATIVE MIN WITHIN NE/LY FLOW BELOW 4 KFT. EXPECT THIS TREND TO CONTINUE OVER THE NEXT FEW HRS AND HAVE ADJ QPF GRIDS TO FAVOR WRN UPSTATE AND NE GA ALONG WITH FAR SW BR THROUGH 12Z. THE SFC LOW WILL MOVE INLAND ACROSS THE SC LOW COUNTRY AND SE/RN GA TODAY THEN STALL OUT WHILE BECOMING LESS DEFINED. MEANWHILE...A NE/RN SFC RIDGE WILL CONTINUE TO BUILD IN TO SOME DEGREE. THE 12 KM NAM IS LESS AMPLIFIED WITH THE RIDGING THAN THE 20 KM GFS AND THIS WILL MAKE A BIG DIFFERENCE AS TO THE AMOUNT OF ISENT LIFT AND 300 K SAT PRES DEFS. WITH LESS LLVL FORCING AND THE RAP MODEL SHOWING RELATIVE DRYING ALOFT THROUGHOUT THE DAY...A CASE CAN BE MADE FOR A RELATIVELY LOW QPF RESPONSE OVER THE UPSTATE AND SRN NE GA. ALTHOUGH ISOL NAM CONVEC SOUTH WOULD ADD LOCALIZED HIGH AMOUNTS OF QPF OVER AREAS WITH THE BEST 24-PRECIP. THE GFS IS SOMEWHAT SIMILAR WITH THIS IDEA YET WITH NO GOOD CONVEC POTENTIAL AND A LITTLE MORE NON/MTN STRATIFORM QPF RESPONSE. IN ANY CASE...THE BEST AREA FOR PRECIP ACCUMS THROUGH THE PERIOD WILL BE ALONG THE BR WHERE AN INCH TO AN INCH AND A QUARTER COULD FALL THROUGH 12Z SAT AS LLVL FLOW BTW 3-5 KFT VEERS. THE NON/MTNS WILL GENERALLY SEE AROUND A HALF INCH DURING THIS TIME. HOWEVER...CONVEC WILL BE THE WILDCARD SOUTH IF ENUF MLVL DRYING OCCURS AS STATED ABOVE. THUS...LOCALIZED FLOODING CONCERNS ARE A LITTLE UNCERTAIN...BUT IF HYDRO BECOMES AN ISSUE...IT WILL BE ACROSS THE SRN ZONES AND/OR THE ERN FACING BR LATE TODAY. MAXES WILL BE HELD ABOUT 10-12 DEGREES BELOW NORMAL MOST LOCALES WITH MINS A COUPLE DEGREES ABOVE NORMAL. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 315 AM FRIDAY...MODELS STILL DISAGREE WITH HOW THE ONGOING RAIN EVENT WILL UNWIND ON SATURDAY AND SATURDAY NIGHT...ALTHO THERE IS GENERAL AGREEMENT IN SHIFTING THE DEEPER MOISTURE AND BETTER FORCING TO THE N BY SATURDAY AFTERNOON. EVEN THE NAM...WHICH WAS A HOLDOUT...NOW HAS THE BEST Q-CONVERGENCE AND UPPER DIVERGENCE ACROSS VA/WV BY 18Z SATURDAY. THE DEEP MOISTURE PLUME SHOULD ALSO BE DIRECTED UP ACROSS THE DELMARVA/TIDEWATER REGION BY THAT TIME AS WELL. THAT SUGGESTS WE SHOULD NOT HAVE MUCH OF A HEAVY PRECIP THREAT MUCH BEYOND 12Z SATURDAY...WHICH IS GOOD. THE PROBLEM IS MAINLY WITH LOW LEVEL MOISTURE AND FORCING... AND THE NAM STILL HAS MUCH MORE ISENTROPIC LIFT OVER THE NC PIEDMONT/FOOTHILLS AND A MORE EASTERLY FLOW AT 850MB DIRECTED AT THE NC MTNS. THUS...NO SURPRISE THAT THE NAM HOLDS ONTO PRECIP PRODUCTION ACROSS THOSE AREAS RIGHT THRU SUNDAY NIGHT. MEANWHILE...THE GFS OPENS UP MORE OF A HOLE ACROSS UPSTATE SC AND GRADUALLY ELIMINATES PRECIP FROM THERE TO THE POINT WHERE IT HAS MINIMAL PRECIP ACROSS THE MTNS FROM SATURDAY NIGHT ONWARD...AND IS BASICALLY DRY ELSEWHERE. THE ECMWF STILL OFFERS A DECENT COMPROMISE. THUS...WILL RAMP DOWN THE POP SATURDAY...AND THEN HOLD ONTO THE LIKELY NEAR THE NC BLUE RIDGE SATURDAY NIGHT WHERE THE LLVL FORCING WOULD BE BEST. POP WILL BE KEPT AT CHC ACROSS THE REST OF THE AREA. ON SUNDAY...THE CHANCE POP GETS PARED BACK TO THE MTNS WHERE ANY REMAINING LIFT WOULD BE THE BEST. THE REST OF THE FCST HAS TOKEN CHC/SLIGHT CHC POP UNTIL WE GET BETTER MODEL CONSENSUS. TEMPS WILL BE SEASONALLY COOL AS WE DEAL WITH THE REMNANTS OF THE COLD AIR DAMMING WEDGE. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 340 AM FRIDAY...HAVE TABLED THE MEDIUM RANGE FOR NOW DUE TO ONGOING FLOOD CONCERNS. NO CHANGES WERE MADE AT THIS TIME. REMAINDER OF PREVIOUS DISCUSSION... THE EXTENDED PERIOD BEGINS WITH THE WEEKEND RAINFALL EVENT ON THE WANE AND DRIER CONDITIONS BUILDING IN ACROSS THE FORECAST AREA. WHILE FLOW ALOFT WILL BE SOUTHERLY THANKS TO A CUT-OFF 500MB LOW OVER SOUTH TEXAS AND AN ANTICYCLONE OVER THE WESTERN SARGASSO SEA...SURFACE HIGH PRESSURE AND A LACK OF NOTABLE SHORTWAVES IN THE FLOW ALOFT SHOULD KEEP THE AREA MOSTLY DRY THROUGH MIDDAY TUESDAY. THEREAFTER...THERE IS GENERAL AGREEMENT THAT A LONGWAVE TROUGH WILL MOVE ACROSS THE NORTHERN HALF OF THE U.S. AND CANADA AND AN ASSOCIATED SURFACE LOW PRESSURE SYSTEM AND ATTENDANT COLD FRONT WILL APPROACH OUR AREA ON WEDNESDAY. BOTH THE GFS AND THE ECMWF ARE NOT EXCITED ABOUT NOTABLE RAINFALL AS A RESULT OF THE FRONTAL PASSAGE...HOWEVER...THE GFS CONTINUES TO BE BULLISH ON A MODEST BUT WELL-DEFINED SURFACE LOW MOVING NORTHWARD OVER THE CENTRAL GULF AND APPROACHING THE LOUISIANA COAST BY TUESDAY AFTERNOON. THE ECMWF WEAKENS THE LOW TO AN OPEN TROUGH OVER THE NORTHERN GULF. BOTH MODELS DO NOT BRING THE FEATURE INLAND...HOWEVER THE GFS KEEPS THE SOUTHERN APPALACHIANS IN A MOISTURE-RICH ENVIRONMENT WITH A TROPICAL CONNECTION TO THE CARIBBEAN AND EJECTS ROUNDS OR BANDS OF CONVECTIVE PRECIP NORTH FROM THE GULF LOW ACROSS THE DEEP SOUTH AND INTO OUR AREA BEGINNING TUESDAY EVENING AND LASTING THROUGH WEDNESDAY. THE ECMWF PERSISTS WITH WEAK NORTHEASTERLY FLOW ACROSS MUCH OF THE SOUTHEAST HEADING INTO THURSDAY. AT THIS TIME THE FORECAST MAINTAINS SLIGHT CHANCE TO CHANCE POPS DURING THE MID-WEEK PERIOD GIVEN THE DECENT MOISTURE THAT REMAINS IN PLACE FOLLOWING THE EVENT ENDING ON SUNDAY...THE ANTICIPATED FRONTAL PASSAGE...AND THE PERSISTENCE OF BOTH MODELS OVER THE PAST FEW RUNS OF SUGGESTING SOME ACTIVITY IN THE GULF MOVING TOWARDS THE COAST. NEVERTHELESS...BOTH THE ECMWF AND GFS AGREE THAT A STRONG 1028MB SURFACE HIGH BUILDS IN ACROSS THE NORTHEAST U.S. ON THE CONFLUENT SIDE OF THE UPPER-LEVEL LONGWAVE TROUGH AND WEDGES DOWN ACROSS MUCH OF THE SOUTHEAST U.S.... SIGNIFICANTLY DRYING US OUT THROUGH THE END OF THE PERIOD ON FRIDAY MORNING. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... AT KCLT AND ELSEWHERE...MAIN CHANGE TO FCST HAS BEEN TO GO MUCH MORE PESSIMISTIC THRU THE DAY WITH MVFR VSBY IN -RADZ AND IFR CIGS. GUSTY NELY WINDS WILL CONTINUE THRU MOST OF THE PERIOD AS WELL. VERY GOOD MOISTURE FLUX CONTINUING OFF THE ATL ASSOCIATED WITH A DEEP PW PLUME HAS MAINTAINED STEADY STATE FLIGHT CONDS THIS MORNING. RAP SOUNDINGS SHOW SAT PROFILES THROUGH THE PERIOD WITH LITTLE WAVERING IN CIGS OUTSIDE OF LIMITED NOCTURNAL LIFTING. WINDS REMAIN NE/LY NON/MTNS WITH LOW/END TO MODERATE GUSTS THROUGH THE MORNING AND A POSSIBLE RETURN THIS EVENING AT KCLT. KAVL AND MTN VICINITY AIRPORTS SHOULD EXPERIENCE LLWS ISSUES LATE PERIOD AS LLVL JET SWINGS AROUND SFC TROF. A DECREASE IN CIG HEIGHTS TO MFVR/IFR IS ANTICIPATED AGAIN LATE PERIOD ALL SITES. OUTLOOK...DEEP MOISTURE AND WIDESPREAD LIFT WILL LIKELY RESULT IN RESTRICTIVE CEILINGS AND VISIBILITY PERIODICALLY THRU SATURDAY. IN ADDITION...RAINFALL WILL BE MODERATE TO HEAVY AT TIMES THROUGH SATURDAY. CONFIDENCE TABLE... 14-20Z 20-02Z 02-08Z 08-12Z KCLT MED 61% MED 66% MED 79% HIGH 91% KGSP MED 66% MED 66% MED 70% HIGH 100% KAVL MED 70% MED 73% LOW 54% HIGH 87% KHKY HIGH 83% MED 74% HIGH 81% HIGH 91% KGMU MED 70% MED 66% HIGH 83% MED 75% KAND HIGH 83% MED 61% HIGH 83% HIGH 87% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO/JMP NEAR TERM...RWH/SBK SHORT TERM...PM LONG TERM...JMP/PM AVIATION...RWH/SBK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
631 AM EDT FRI SEP 25 2015 .SYNOPSIS... AN AREA OF LOW PRESSURE NEAR THE ATLANTIC COASTLINE WILL FEED MOISTURE-RICH AIR INTO THE REGION THROUGH MOST OF THE WEEKEND... RESULTING IN A LENGTHY STRETCH OF WIDESPREAD LIGHT TO MODERATE RAINFALL. DRIER CONDITIONS WILL PREVAIL HEADING INTO LATE SUNDAY AND EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... 0630 AM UPDATE...NO MAJOR CHANGES NEEDED TO THE FCST. PRECIP SHIELD REMAINS FAIRLY WIDESPREAD. SOME CONVEC STREETS NOTED OVER THE MIDLANDS WITH DRY AIR ALOFT MIXING DOWN. THIS WILL LOWER POP POTENTIAL ACROSS THE SRN ZONES WITH SOME FILL-IN POSSIBLE AS MLVL Q/CONVG CROSSES OVERHEAD. THUS...WILL LEAVE POP GRADIENT AS IS IN THE GRIDS. RAINFALL REACHING THE ESCARPMENT IS NOT ENTIRELY ANCHORED AS LLVL FLOW REMAINS NE/LY BELOW 4 KFT. UPSLOPE ENHANCEMENT WILL BECOME MORE FAVORABLE THROUGH MID DAY. VERY GOOD MOISTURE FLUX ALIGNED IN DEEP ATL PWAT PLUME CONTINUES ACROSS THE FA THIS MORNING. HEAVIER RAINFALL RATES HAVE BEEN MAINTAINED SOUTH WITH THE UPSLOPE REGIONS REMAINING IN A RELATIVE MIN WITHIN NE/LY FLOW BELOW 4 KFT. EXPECT THIS TREND TO CONTINUE OVER THE NEXT FEW HRS AND HAVE ADJ QPF GRIDS TO FAVOR WRN UPSTATE AND NE GA ALONG WITH FAR SW BR THROUGH 12Z. THE SFC LOW WILL MOVE INLAND ACROSS THE SC LOW COUNTRY AND SE/RN GA TODAY THEN STALL OUT WHILE BECOMING LESS DEFINED. MEANWHILE...A NE/RN SFC RIDGE WILL CONTINUE TO BUILD IN TO SOME DEGREE. THE 12 KM NAM IS LESS AMPLIFIED WITH THE RIDGING THAN THE 20 KM GFS AND THIS WILL MAKE A BIG DIFFERENCE AS TO THE AMOUNT OF ISENT LIFT AND 300 K SAT PRES DEFS. WITH LESS LLVL FORCING AND THE RAP MODEL SHOWING RELATIVE DRYING ALOFT THROUGHOUT THE DAY...A CASE CAN BE MADE FOR A RELATIVELY LOW QPF RESPONSE OVER THE UPSTATE AND SRN NE GA. ALTHOUGH ISOL NAM CONVEC SOUTH WOULD ADD LOCALIZED HIGH AMOUNTS OF QPF OVER AREAS WITH THE BEST 24-PRECIP. THE GFS IS SOMEWHAT SIMILAR WITH THIS IDEA YET WITH NO GOOD CONVEC POTENTIAL AND A LITTLE MORE NON/MTN STRATIFORM QPF RESPONSE. IN ANY CASE...THE BEST AREA FOR PRECIP ACCUMS THROUGH THE PERIOD WILL BE ALONG THE BR WHERE AN INCH TO AN INCH AND A QUARTER COULD FALL THROUGH 12Z SAT AS LLVL FLOW BTW 3-5 KFT VEERS. THE NON/MTNS WILL GENERALLY SEE AROUND A HALF INCH DURING THIS TIME. HOWEVER...CONVEC WILL BE THE WILDCARD SOUTH IF ENUF MLVL DRYING OCCURS AS STATED ABOVE. THUS...LOCALIZED FLOODING CONCERNS ARE A LITTLE UNCERTAIN...BUT IF HYDRO BECOMES AN ISSUE...IT WILL BE ACROSS THE SRN ZONES AND/OR THE ERN FACING BR LATE TODAY. MAXES WILL BE HELD ABOUT 10-12 DEGREES BELOW NORMAL MOST LOCALES WITH MINS A COUPLE DEGREES ABOVE NORMAL. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 315 AM FRIDAY...MODELS STILL DISAGREE WITH HOW THE ONGOING RAIN EVENT WILL UNWIND ON SATURDAY AND SATURDAY NIGHT...ALTHO THERE IS GENERAL AGREEMENT IN SHIFTING THE DEEPER MOISTURE AND BETTER FORCING TO THE N BY SATURDAY AFTERNOON. EVEN THE NAM...WHICH WAS A HOLDOUT...NOW HAS THE BEST Q-CONVERGENCE AND UPPER DIVERGENCE ACROSS VA/WV BY 18Z SATURDAY. THE DEEP MOISTURE PLUME SHOULD ALSO BE DIRECTED UP ACROSS THE DELMARVA/TIDEWATER REGION BY THAT TIME AS WELL. THAT SUGGESTS WE SHOULD NOT HAVE MUCH OF A HEAVY PRECIP THREAT MUCH BEYOND 12Z SATURDAY...WHICH IS GOOD. THE PROBLEM IS MAINLY WITH LOW LEVEL MOISTURE AND FORCING... AND THE NAM STILL HAS MUCH MORE ISENTROPIC LIFT OVER THE NC PIEDMONT/FOOTHILLS AND A MORE EASTERLY FLOW AT 850MB DIRECTED AT THE NC MTNS. THUS...NO SURPRISE THAT THE NAM HOLDS ONTO PRECIP PRODUCTION ACROSS THOSE AREAS RIGHT THRU SUNDAY NIGHT. MEANWHILE...THE GFS OPENS UP MORE OF A HOLE ACROSS UPSTATE SC AND GRADUALLY ELIMINATES PRECIP FROM THERE TO THE POINT WHERE IT HAS MINIMAL PRECIP ACROSS THE MTNS FROM SATURDAY NIGHT ONWARD...AND IS BASICALLY DRY ELSEWHERE. THE ECMWF STILL OFFERS A DECENT COMPROMISE. THUS...WILL RAMP DOWN THE POP SATURDAY...AND THEN HOLD ONTO THE LIKELY NEAR THE NC BLUE RIDGE SATURDAY NIGHT WHERE THE LLVL FORCING WOULD BE BEST. POP WILL BE KEPT AT CHC ACROSS THE REST OF THE AREA. ON SUNDAY...THE CHANCE POP GETS PARED BACK TO THE MTNS WHERE ANY REMAINING LIFT WOULD BE THE BEST. THE REST OF THE FCST HAS TOKEN CHC/SLIGHT CHC POP UNTIL WE GET BETTER MODEL CONSENSUS. TEMPS WILL BE SEASONALLY COOL AS WE DEAL WITH THE REMNANTS OF THE COLD AIR DAMMING WEDGE. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 340 AM FRIDAY...HAVE TABLED THE MEDIUM RANGE FOR NOW DUE TO ONGOING FLOOD CONCERNS. NO CHANGES WERE MADE AT THIS TIME. REMAINDER OF PREVIOUS DISCUSSION... THE EXTENDED PERIOD BEGINS WITH THE WEEKEND RAINFALL EVENT ON THE WANE AND DRIER CONDITIONS BUILDING IN ACROSS THE FORECAST AREA. WHILE FLOW ALOFT WILL BE SOUTHERLY THANKS TO A CUT-OFF 500MB LOW OVER SOUTH TEXAS AND AN ANTICYCLONE OVER THE WESTERN SARGASSO SEA...SURFACE HIGH PRESSURE AND A LACK OF NOTABLE SHORTWAVES IN THE FLOW ALOFT SHOULD KEEP THE AREA MOSTLY DRY THROUGH MIDDAY TUESDAY. THEREAFTER...THERE IS GENERAL AGREEMENT THAT A LONGWAVE TROUGH WILL MOVE ACROSS THE NORTHERN HALF OF THE U.S. AND CANADA AND AN ASSOCIATED SURFACE LOW PRESSURE SYSTEM AND ATTENDANT COLD FRONT WILL APPROACH OUR AREA ON WEDNESDAY. BOTH THE GFS AND THE ECMWF ARE NOT EXCITED ABOUT NOTABLE RAINFALL AS A RESULT OF THE FRONTAL PASSAGE...HOWEVER...THE GFS CONTINUES TO BE BULLISH ON A MODEST BUT WELL-DEFINED SURFACE LOW MOVING NORTHWARD OVER THE CENTRAL GULF AND APPROACHING THE LOUISIANA COAST BY TUESDAY AFTERNOON. THE ECMWF WEAKENS THE LOW TO AN OPEN TROUGH OVER THE NORTHERN GULF. BOTH MODELS DO NOT BRING THE FEATURE INLAND...HOWEVER THE GFS KEEPS THE SOUTHERN APPALACHIANS IN A MOISTURE-RICH ENVIRONMENT WITH A TROPICAL CONNECTION TO THE CARIBBEAN AND EJECTS ROUNDS OR BANDS OF CONVECTIVE PRECIP NORTH FROM THE GULF LOW ACROSS THE DEEP SOUTH AND INTO OUR AREA BEGINNING TUESDAY EVENING AND LASTING THROUGH WEDNESDAY. THE ECMWF PERSISTS WITH WEAK NORTHEASTERLY FLOW ACROSS MUCH OF THE SOUTHEAST HEADING INTO THURSDAY. AT THIS TIME THE FORECAST MAINTAINS SLIGHT CHANCE TO CHANCE POPS DURING THE MID-WEEK PERIOD GIVEN THE DECENT MOISTURE THAT REMAINS IN PLACE FOLLOWING THE EVENT ENDING ON SUNDAY...THE ANTICIPATED FRONTAL PASSAGE...AND THE PERSISTENCE OF BOTH MODELS OVER THE PAST FEW RUNS OF SUGGESTING SOME ACTIVITY IN THE GULF MOVING TOWARDS THE COAST. NEVERTHELESS...BOTH THE ECMWF AND GFS AGREE THAT A STRONG 1028MB SURFACE HIGH BUILDS IN ACROSS THE NORTHEAST U.S. ON THE CONFLUENT SIDE OF THE UPPER-LEVEL LONGWAVE TROUGH AND WEDGES DOWN ACROSS MUCH OF THE SOUTHEAST U.S.... SIGNIFICANTLY DRYING US OUT THROUGH THE END OF THE PERIOD ON FRIDAY MORNING. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... AT KCLT AND ELSEWHERE...VERY GOOD MOISTURE FLUX CONTINUING OFF THE ATL ASSOCIATED WITH A DEEP PW PLUME HAS MAINTAINED STEADY STATE FLIGHT CONDS THIS MORNING. RAP SOUNDINGS SHOW SAT PROFILES THROUGH THE PERIOD WITH LITTLE WAVERING IN CIGS OUTSIDE OF LIMITED NOCTURNAL LIFTING. GENERALLY...A TRANSITION FROM IFR TO MVFR CIGS IN ISOL LOWERING VSBYS WITH SHRA. WINDS REMAIN NE/LY NON/MTNS WITH LOW/END TO MODERATE GUSTS THROUGH THE MORNING AND A POSSIBLE RETURN THIS EVENING AT KCLT. KAVL AND MTN VICINITY AIRPORTS SHOULD EXPERIENCE LLWS ISSUES LATE PERIOD AS LLVL JET SWINGS AROUND SFC TROF. A DECREASE IN CIG HEIGHTS TO MFVR/IFR IS ANTICIPATED AGAIN LATE PERIOD ALL SITES. OUTLOOK...DEEP MOISTURE AND WIDESPREAD LIFT WILL LIKELY RESULT IN RESTRICTIVE CEILINGS AND VISIBILITY PERIODICALLY THRU SATURDAY. IN ADDITION...RAINFALL WILL BE MODERATE TO HEAVY AT TIMES THROUGH SATURDAY. CONFIDENCE TABLE... 10-16Z 16-22Z 22-04Z 04-06Z KCLT HIGH 100% HIGH 92% HIGH 100% HIGH 100% KGSP HIGH 83% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 95% HIGH 91% HIGH 97% HIGH 84% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 83% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 100% HIGH 91% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO/JMP NEAR TERM...SBK SHORT TERM...PM LONG TERM...JMP/PM AVIATION...SBK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
549 AM MDT FRI SEP 25 2015 .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 345 AM MDT FRI SEP 25 2015 A QUIET WEATHER PERIOD WILL CONTINUE OVER THE NEXT SEVERAL DAYS WITH UPPER-LEVEL RIDGING IN PLACE. A MOIST LOW-LEVEL AIR MASS REMAINS IN PLACE WITH WIDESPREAD SURFACE DEW POINTS IN THE 40S/50S. LIGHT WINDS AND CLEAR SKIES HAVE ONCE AGAIN ALLOWED PATCHY FOG TO DEVELOP ACROSS THE NE PANHANDLE AND PLATTE RIVER VALLEY EXTENDING INTO SOUTHEASTERN WY. STRONG SUBSIDENCE SUGGESTS SUNNY SKIES WILL PREVAIL BEYOND ABOUT 15Z WHEN THE HRRR HINTS AT FOG STARTING TO ERODE. WE COULD VERY WELL SEE THIS AGAIN TONIGHT AS THE NAM SHOWS A RATHER ROBUST INCREASE IN BOUNDARY LAYER MOISTURE AFTER 03Z SAT VIA MOIST SOUTHEASTERLY LOW- LEVEL FLOW. INHIBITING FACTOR FOR FOG WOULD BE STRONGER WINDS OWING TO A HIGHER SURFACE PRESSURE GRADIENT THAN WE ARE SEEING ATTM...BUT NAM/GFS BUFKIT SOUNDINGS BOTH OFFER ENOUGH SUPPORT TO ADD PATCHY FOG TO THE GRIDS. IT STILL LOOKS VERY WARM THIS WEEKEND WITH H7 TEMPS IN THE +13 TO +15 DEG C RANGE ACROSS MOST OF THE CWA ON SAT/SUN. EXPECT TO SEE WIDESPREAD HIGHS IN THE 85-95 DEG F RANGE...WHICH MAY BE NEAR RECORD AT SOME SITES. AREAS ALONG AND WEST OF THE LARAMIE RANGE WILL SEE AFTERNOON HUMIDITIES BELOW 15 PERCENT EACH AFTERNOON...BUT MID- LEVEL FLOW IS NOT PARTICULARLY STRONG WITH A RIDGE AXIS PARKED OVER THE CENTRAL ROCKIES. STRONG MIXING WILL ALMOST UNDOUBTEDLY YIELD A FEW GUSTS AROUND 20-25 MPH...BUT OPTED NOT TO ISSUE ANY FIRE WEATHER HIGHLIGHTS AS ANY POTENTIAL FOR RED FLAG CONDITIONS WILL BE MARGINAL AT BEST. .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 345 AM MDT FRI SEP 25 2015 MONDAY WILL LIKELY BE THE WARMEST DAY OF THE EXTENDED PERIOD WITH STRONG RIDGING ALOFT AND 700MB TEMPS AROUND 12C. A WEAK COLD FRONT WILL MOVE ACROSS THE PLAINS ON MON NIGHT WITH WINDS BECOME EASTERLY BY TUES. THE GFS CONTINUES TO BE MORE BULLISH WITH QPF ON TUES AND TUES NIGHT AS UPPER LEVEL DISTURBANCES INTERACT WITH THE LLVL UPSLOPE. THE ECMWF SHOWS LOW STRATUS TO THE EAST OF THE LARAMIE RANGE WITH DRIZZLE/LIGHT RAIN SHOWERS...HOWEVER DEEP LAYER UPWARD MOTION IS LACKING. HAVE 20 PERCENT POPS FROM TUES INTO TUES NIGHT WITH THE MODEL UNCERTAINTY STILL HIGH. THERE WILL BE A COOLDOWN FOR TUES BEHIND THE FRONT. THE ECMWF SHOWS QUICKLY RISING HEIGHTS/TEMPS BY WED WHEREAS THE GFS HAS THE UPPER TROUGH AXIS MOVING OVERHEAD. WINDS THROUGHOUT THE LONG TERM WILL BE QUITE LIGHT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 546 AM MDT FRI SEP 25 2015 IFR CONDITIONS AND AREAS OF FOG WILL CONTINUE TO AFFECT THE NEBRASKA PANHANDLE SITES THROUGH 15-16Z. VIS IN FOG COULD BE REDUCED TO A QUARTER MILE AT TIMES. VFR CONDITIONS WILL PREVAIL ACROSS SOUTHEAST WY. WINDS WILL BE LIGHT THROUGH THE DAY. && .FIRE WEATHER... ISSUED AT 345 AM MDT FRI SEP 25 2015 WARM AND DRY WEATHER WILL CONTINUE THROUGH THE WEEKEND. AREAS ALONG AND WEST OF THE LARAMIE RANGE WILL LIKELY SEE MINIMUM HUMIDITIES AT OR BELOW 15 PERCENT EACH AFTERNOON THROUGH SUN. ELEVATED CONDITIONS ARE LIKELY OVER THE WEEKEND AS WIND GUSTS COULD APPROACH 20-25 MPH AT TIMES. NO FIRE WEATHER HIGHLIGHTS ARE EXPECTED AT THIS TIME AS WINDS ARE EXPECTED TO REMAIN JUST BELOW CRITICAL THRESHOLDS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...CLH LONG TERM...ZF AVIATION...ZF FIRE WEATHER...CLH
AREA FORECAST DISCUSSION
NWS MIAMI FL
346 PM EDT FRI SEP 25 2015 .SHORT TERM (TONIGHT-MON NIGHT)... COASTAL FLOOD STATEMENT CONTINUES THROUGH MONDAY NIGHT, NOW FOR WEST AND EAST COASTS. ANY RAINFALL THIS WEEKEND, EVEN MORE SO AROUND HIGH TIDE, WILL EXACERBATE THE SITUATION. LESS HIGH CLOUDS TODAY, HAS ALLOWED FOR BETTER THUNDERSTORM DEVELOPMENT THIS AFTERNOON. THE EAST COAST SEA BREEZE HAS ALREADY PROGRESSED INLAND, SUCH THAT MOST ACTIVITY MAY BE OVER THE INTERIOR OR FAR WESTERN SUBURBS. WITH WEAK WIND PROFILE STILL IN PLACE, AND SHOWERS CURRENTLY DRIFTING TO THE NORTHEAST, HRRR SHOWS THE POSSIBILITY OF A FEW STORMS MOVING BACK TOWARDS THE METRO AND BEACHES INTO EARLY EVENING. THIS PROCESS MAY HAPPEN A LITTLE EARLIER THOUGH THROUGH PALM BEACH COUNTY, WITH MORE WESTERLY COMPONENT IN THE MEAN WIND/STORM MOTION THERE. HEAVY RAINFALL AGAIN APPEARS TO BE THE MAIN THREAT CONSIDERING MOVEMENT. MITIGATING FACTOR FOR ANY STRONGER STORMS TODAY WILL BE A NOTABLE MIDLEVEL INVERSION FROM THIS MORNING`S RAOB. MODEL SOUNDING FORECASTED AFTERNOON CAPE ISN`T VERY IMPRESSIVE. TONIGHT-SATURDAY...AS PERSISTENT SURFACE TROUGH OVER CENTRAL FL CONTINUES TO WASH OUT, EASTERLY COMPONENT WILL BECOME SOMEWHAT DEEPER, ALTHOUGH SPEEDS WILL REMAIN RATHER LIGHT. SHOWERS AND A FEW STORMS WILL REMAIN POSSIBLE LATE NIGHT AND THROUGH THE MORNING HOURS. WITH SIMILAR PROGRESSION OF THE SEA BREEZE EXPECTED SATURDAY, MOST STORMS ARE EXPECTED TO BE INTERIOR AND OFF THE COAST INTO THE AFTERNOON HOURS. PERHAPS A SMALLER CHC OF ACTIVITY BLEEDING BACK TOWARDS THE EAST COAST THAN TODAY. INSTABILITY IS NOTHING TO GET EXCITED ABOUT WITH SIMILAR H7-H5 LAPSE RATES AND H5 TEMPS TO TODAY. IF MIDLEVEL INVERSION FROM THIS MORNING`S SOUNDING REMAINS, THAT COULD RESTRICT ACTIVITY AGAIN. PWATS THOUGH REMAIN ABOVE 2" AND DEEP MOISTURE REMAINS. SUNDAY-MONDAY... EASTERLY FLOW TRIES TO BECOME A LITTLE DEEPER AND STRONGER, ALTHOUGH LARGE SURFACE HIGH MOVING OFF THE MID ATLANTIC COAST IS HAVING PROBLEMS EXERTING INFLUENCE, WITH WEAK LOW PRESSURE/SURFACE TROUGH STUCK ALONG THE CAROLINA COAST SUNDAY. H5 TEMP PERHAPS WARMS ABOVE -6C. FOCUS FOR AFTERNOON STORMS WILL CONTINUE TO BE INTERIOR, WITH COVERAGE INCREASING OVER THE WEST COAST ALSO. OPERATIONAL GFS CONTINUES TO BE THE MOST AGGRESSIVE WITH AREA OF LOW PRESSURE MOVING INTO THE WESTERN OR CENTRAL GULF OF MEXICO SUNDAY AND MONDAY. THE ECMWF IS A LITTLE FARTHER EAST THAN PREVIOUS RUNS, BUT CONTINUES WEAKER. NHC CONTINUES TO INDICATE A NOT PARTICULARLY FAVORABLE ENVIRONMENT FOR ANY DEVELOPMENT IN THEIR 5 DAY OUTLOOK AS THE AREA OF LOW PRESSURE POSSIBLY CONTINUES ON A NORTHERLY TRACK THROUGH THE GULF OF MEXICO AFTER IT CROSSES THE YUCATAN PENINSULA. AS THIS OCCURS, WINDS WILL VEER THROUGH THE COLUMN, BECOMING MORE SSE AT THE SURFACE AND SSW ALOFT. THUS, STORMS MAY BECOME MORE FAVORABLE ALONG THE EAST COAST WITH THE CHANGE IN WIND DIRECTION. HOWEVER, WITH AN H5 RIDGE STRETCHING FURTHER ACROSS THE WESTERN ATLANTIC THAN THIS WEEKEND, H5 TEMPS CONTINUE TO WARM WITH RATHER UNFAVORABLE MIDLEVEL LAPSE RATES. MODEL/BLENDED POPS MAY BE DRIVEN BY THE DEEP MOIST SOUTHERLY FLOW EVOLVING AT ALL LEVELS, THAN TYPICAL AFTERNOON THUNDERSTORMS. .LONG TERM (TUE-FRI)... WE WILL STILL NEED TO WATCH MOVEMENT OF LOW PRESSURE AND HOW FAR EAST DEEP TROPICAL MOISTURE AND HEAVY RAINFALL SPREADS TOWARDS OUR GULF COAST REGION, ALTHOUGH CURRENT GUIDANCE POSSIBLY HAS THE LOW STAYING WELL NORTH AND WEST OF SOUTH FLORIDA. CLOSED MID AND UPPER LEVEL LOW OVER TX/LA EARLY NEXT WEEK, OPENS UP AS A TROUGH MOVES TOWARDS THE EASTERN SEABOARD TOWARDS THE MIDDLE AND END OF NEXT WEEK. ECMWF/GFS DIFFER ON THE DEPTH AND STRENGTH OF THIS TROUGH. THE GFS ACTUALLY HAS A GOOD CHUNK OF MIDLEVEL DRY AIR ARRIVING INTO WEDNESDAY, ASSOCIATED WITH STRONGER RIDGING AND SUBSIDENCE OVER SOUTH FLORIDA. THIS MAY MITIGATE A WIND FIELD WHICH MAY BECOME MORE FAVORABLE FOR STORMS FOCUSED THROUGH THE INTERIOR AND EAST COAST PER THE DEEPER ECMWF LATE NEXT WEEK. && .MARINE... AN EASTERLY WIND FLOW WILL CONTINUE...PREVAILING AT 5-10 KT THEN INCREASING JUST A TAD EARLY NEXT WEEK. SEAS WILL PREVAIL AT 4 FT OR LESS WITH A SMALL NORTH SWELL ATLANTIC WATERS. SURFACE WINDS MAY VEER SOMEWHAT INTO EARLY NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 75 89 77 89 / 30 40 20 40 FORT LAUDERDALE 76 88 78 89 / 30 30 30 30 MIAMI 77 90 78 90 / 30 50 40 40 NAPLES 75 90 76 90 / 20 40 40 50 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ SHORT TERM...21/KM LONG TERM....21/KM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
147 PM MDT FRI SEP 25 2015 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 1245 PM MDT FRI SEP 25 2015 AN UPPER LEVEL LOW PRESSURE AREA CURRENTLY SPINNING OVER NORTHEAST KANSAS IS FORECAST MOVE SOUTHWEST TONIGHT REACHING WEST CENTRAL OKLAHOMA BY MORNING. DURING THE AFTERNOON HOURS THE LOW CONTINUES SOUTH-SOUTHWEST WITH A SHARP UPPER RIDGE AXIS JUST WEST OF THE AREA. MAIN WEATHER CONCERNS TONIGHT THROUGH MID MORNING SATURDAY WILL BE INCREASING BOUNDARY LAYER MOISTURE RESULTING IN WIDESPREAD LOW CLOUDS AND FOG. HAVE FOLLOWED THE HRRR REGARDING PLACEMENT AND LOWEST VISIBILITIES OF FOG WHICH FAVOR THE WESTERN 2/3 OF THE AREA. CURRENTLY HAVE VISIBILITIES DOWN TO 1/2 MILE IN THIS AREA. IF THE MODEL GUIDANCE IS RIGHT DENSE FOG WITH VISIBILITIES 1/4 MILE OR LESS WILL DEVELOP. WILL LET EVENING SHIFT GET ANOTHER LOOK AT 18Z AND 00Z MODEL DATA IN HOPES OF FINE TUNING AREAS UNDER THE GUN FOR DENSE FOG AND POSSIBLY ISSUE AN ADVISORY. LOW TEMPERATURES TONIGHT GENERALLY IN THE UPPER 40S TO MID 50S. HIGHS ON SATURDAY GENERALLY IN THE MID 70S TO LOW 80S. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 136 PM MDT FRI SEP 25 2015 UPPER RIDGE CENTERED OVER THE FOUR CORNERS WILL HOLD FIRM THROUGH MOST OF THE UPCOMING WEEK...WITH THE NEXT SHORTWAVE TROUGH CROSSING THE CENTRAL ROCKIES ON FRIDAY BRINGING WITH IT A CHANCE FOR THUNDERSTORMS. UNTIL THEN...DRY CONDITIONS AND ABOVE NORMAL TEMPERATURES ARE EXPECTED. LOW CLOUDS AND AREAS OF FOG WILL ALSO PERSIST IN THE OVERNIGHT HOURS SATURDAY NIGHT/SUNDAY MORNING AND POSSIBLY AGAIN SUNDAY NIGHT/MONDAY MORNING WITH PLENTIFUL LOW LEVEL MOISTURE. THERE WILL BE A WEAK COLD FRONT ATTEMPTING TO SLIP SOUTHWARD INTO THE AREA MONDAY AFTERNOON AND EVENING WITH INCREASING CLOUDS. HOWEVER...UPPER SUPPORT WILL BE DISPLACED FAR TO THE NORTH RULING OUT MOST IF NOT ALL PRECIPITATION CHANCES BUT REINFORCING MOIST LOW LEVELS WITH A POST FRONTAL UPSLOPE FLOW THROUGH TUESDAY. FOR THE LATE WEEK SYSTEM...INSTABILITY CURRENTLY LOOKS RATHER MEAGER BUT DEEP LAYER SHEAR WILL BE EXCELLENT ON FRIDAY...ON THE ORDER OF 50KTS...SO A SEVERE THREAT CANNOT BE RULED OUT JUST YET. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1130 AM MDT FRI SEP 25 2015 KGLD...MVFR CIGS EXPECTED FROM TAF ISSUANCE THROUGH APPROXIMATELY 23Z BEFORE IMPROVING TO VFR...COULD BE A FEW HOURS SOONER. WINDS GENERALLY FROM THE NORTH TO NORTHEAST AROUND 11KTS. AFTER 05Z STRATUS WITH VLIFR CIGS AND VISIBILITY IN IFR/VLIFR CATEGORY EXPECTED TO MOVE IN FROM THE EAST/NORTHEAST AND CONTINUE THROUGH NEARLY THE REST OF THE TAF PERIOD. SOME DRIZZLE ALSO POSSIBLE. VIS MAY RISE TO MVFR CATEGORY BY 15Z THEN VFR AFTER 17Z BUT CIGS WILL KEEP TERMINAL IN THE IFR/VLIFR CATEGORY. KMCK...MVFR CIGS EXPECTED FROM TAF ISSUANCE THROUGH ROUGHLY 02Z BEFORE STRATUS/FOG MOVE IN FROM THE EAST/NORTHEAST BRINGING IFR/VLIFR CONDITIONS THROUGH 17Z. AFTER 17Z VIS EXPECTED TO BE VFR BUT CIGS MAY ONLY RISE TO MVFR CATEGORY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...99 LONG TERM...024 AVIATION...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1245 PM MDT FRI SEP 25 2015 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 1245 PM MDT FRI SEP 25 2015 AN UPPER LEVEL LOW PRESSURE AREA CURRENTLY SPINNING OVER NORTHEAST KANSAS IS FORECAST MOVE SOUTHWEST TONIGHT REACHING WEST CENTRAL OKLAHOMA BY MORNING. DURING THE AFTERNOON HOURS THE LOW CONTINUES SOUTH-SOUTHWEST WITH A SHARP UPPER RIDGE AXIS JUST WEST OF THE AREA. MAIN WEATHER CONCERNS TONIGHT THROUGH MID MORNING SATURDAY WILL BE INCREASING BOUNDARY LAYER MOISTURE RESULTING IN WIDESPREAD LOW CLOUDS AND FOG. HAVE FOLLOWED THE HRRR REGARDING PLACEMENT AND LOWEST VISIBILITIES OF FOG WHICH FAVOR THE WESTERN 2/3 OF THE AREA. CURRENTLY HAVE VISIBILITIES DOWN TO 1/2 MILE IN THIS AREA. IF THE MODEL GUIDANCE IS RIGHT DENSE FOG WITH VISIBILITIES 1/4 MILE OR LESS WILL DEVELOP. WILL LET EVENING SHIFT GET ANOTHER LOOK AT 18Z AND 00Z MODEL DATA IN HOPES OF FINE TUNING AREAS UNDER THE GUN FOR DENSE FOG AND POSSIBLY ISSUE AN ADVISORY. LOW TEMPERATURES TONIGHT GENERALLY IN THE UPPER 40S TO MID 50S. HIGHS ON SATURDAY GENERALLY IN THE MID 70S TO LOW 80S. .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 206 AM MDT FRI SEP 25 2015 MODEL FORECASTS ARE IN GOOD AGREEMENT TO THE UPPER FLOW PATTERN STARTING ON MONDAY WITH A RIDGE LOCATED OVER THE SOUTH CENTRAL PLAINS AND A TROUGH POSITIONED OFF THE COAST OF CALIFORNIA. THIS UPPER LEVEL RIDGE WILL CONTINUE TO INFLUENCE THE TRI STATE AREA THROUGH TUESDAY...SO EXPECTING DRY CONDITIONS AND SEASONABLY WARM TEMPERATURES IN THE MID TO UPPER 80S ACROSS THE FORECAST AREA. MODEL SOLUTIONS BEGIN TO DIVERGE TUESDAY NIGHT INTO WEDNESDAY...WHICH HAS BEEN A CONSISTENT TREND OF INCONSISTENCY OVER THE PAST FEW DAYS. THE GFS AND DGEX MODELS DEPICT A TROUGH SWEEPING ACROSS THE CENTRAL AND NORTHERN HIGH PLAINS DURING THIS PERIOD...WHICH TRANSLATES TO CHANCES FOR PRECIPITATION TO BE GENERATED AT THE SURFACE. HOWEVER...THE ECMWF AND THE CANADIAN MODELS SHOW A SHORTWAVE RIDGE BECOMING MORE AMPLIFIED OVER THE FORECAST AREA...WHICH WOULD RESULT IN WARMER TEMPERATURES AND DRY WEATHER. OF THE PAST RUNS...THE ECMWF APPEARS TO BE THE MOST CONSISTENT WITH LATCHING ONTO THE SHORTWAVE RIDGE PATTERN AMPLIFYING IN THIS TIME PERIOD. BECAUSE OF THE CONSISTENCY OF THE ECMWF...THE DECISION WAS MADE TO REMOVE THE CONSENSUS POPS AND HEDGE MORE TOWARDS THE DRY ECMWF FORECAST FOR TUESDAY NIGHT THROUGH WEDNESDAY. BY THURSDAY...MODEL SOLUTIONS ARE VERY DIFFERENT IN REGARDS TO WAVE POSITIONS AND STRENGTH. AS A RESULT...CONSENSUS BLENDS ARE FAIRLY UNRELIABLE WITH THE LACK OF CONFIDENCE IN THE SOLUTIONS. AT THIS POINT ONLY BASED ON PAST CONSISTENCY...THE DECISION WAS MADE TO FOLLOW THE ECMWF AND GO WITH THE DRY FORECAST FOR THE REST OF THE PERIOD. CONSENSUS HIGH TEMPERATURES MAY BE TOO LOW CONSIDERING THAT A FORECAST RIDGE IN PLACE BY THE ECMWF MAY BRING WARMER TEMPERATURES IN THE MID TO UPPER 80S LATER IN THE FORECAST PERIOD...HOWEVER DECIDED TO LEAVE THE TEMPERATURE FORECAST AS IS DUE TO THE VALUES OF BETWEEN 5 AND 10 DEGREES ABOVE CLIMATOLOGY VALUES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1130 AM MDT FRI SEP 25 2015 KGLD...MVFR CIGS EXPECTED FROM TAF ISSUANCE THROUGH APPROXIMATELY 23Z BEFORE IMPROVING TO VFR...COULD BE A FEW HOURS SOONER. WINDS GENERALLY FROM THE NORTH TO NORTHEAST AROUND 11KTS. AFTER 05Z STRATUS WITH VLIFR CIGS AND VISIBILITY IN IFR/VLIFR CATEGORY EXPECTED TO MOVE IN FROM THE EAST/NORTHEAST AND CONTINUE THROUGH NEARLY THE REST OF THE TAF PERIOD. SOME DRIZZLE ALSO POSSIBLE. VIS MAY RISE TO MVFR CATEGORY BY 15Z THEN VFR AFTER 17Z BUT CIGS WILL KEEP TERMINAL IN THE IFR/VLIFR CATEGORY. KMCK...MVFR CIGS EXPECTED FROM TAF ISSUANCE THROUGH ROUGHLY 02Z BEFORE STRATUS/FOG MOVE IN FROM THE EAST/NORTHEAST BRINGING IFR/VLIFR CONDITIONS THROUGH 17Z. AFTER 17Z VIS EXPECTED TO BE VFR BUT CIGS MAY ONLY RISE TO MVFR CATEGORY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...99 LONG TERM...MK AVIATION...99
AREA FORECAST DISCUSSION
NWS JACKSON KY
349 PM EDT FRI SEP 25 2015 .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 349 PM EDT FRI SEP 25 2015 18Z SFC ANALYSIS SHOWS LOW PRESSURE SPREADING NORTH INTO KENTUCKY BENEATH A DEVELOPING UPPER LOW. THIS IS SUPPORTING WAVES OF LIGHT TO MODERATE SHOWERS WORKING EAST TO WEST THROUGH EASTERN KENTUCKY. SO FAR...THE MORE SUBSTANTIAL RAIN HAS BEEN HELD UP OVER MUCH OF THE AREA DUE TO INITIAL DRY AIR AND DOWNSLOPING ON EAST TO NORTHEAST WINDS COMING OFF THE HIGHER TERRAIN. THE CLOUDS AND RAIN HAVE KEPT TEMPERATURES CAPPED THIS DAY WITH READINGS CURRENTLY IN THE LOW TO MID 60S THROUGHOUT EAST KENTUCKY. THE INCREASING SHOWERS HAVE HELPED TO SATURATE MUCH OF THE AREA WITH LOW 60S ACROSS SOUTHEAST PARTS OF THE CWA WHILE MID AND LOW 50S ARE NOTED TO THE NORTHWEST. WINDS...MEANWHILE...ARE GENERALLY FROM THE EAST AT 5 TO 10 KTS WITH OCCASIONAL GUSTS TO 15 KTS. THE MODELS REMAIN IN PRETTY GOOD AGREEMENT ALOFT AS THEY ALL DEPICT A CLOSED LOW FORMING OVER THE TENNESSEE VALLEY...AMID A REGION OF HIGH HEIGHTS...INTO SATURDAY MORNING. THIS UPPER LOW WILL THEN DRIFT NORTH INTO KENTUCKY THROUGH SUNDAY MORNING WHILE AMPLE AMOUNTS OF ENERGY SWIRLS AROUND ITS CENTER. THIS LOW WILL COMMENCE FILLING FOR THE LATTER PART OF THE SHORT TERM PERIOD... LESSENING ITS IMPACT ON SENSIBLE WEATHER FOR THE JKL CWA. GIVEN THE SIMILARITIES AMONG THE MODELS HAVE AGAIN FAVORED THE HIGHER RESOLUTION ONES LIKE THE RAP13 AND HRRR FOR WEATHER SPECIFICS... ALONG WITH THE NAM12 FROM LATER SATURDAY INTO SUNDAY MORNING. SENSIBLE WEATHER WILL FEATURE WAVES OF LIGHT TO MODERATE SHOWERS PUSHING ACROSS EAST KENTUCKY THROUGH THE NIGHT. THESE WILL STILL BE SOMEWHAT LIMITED BY DOWNSLOPING...BUT EVEN SO THERE WILL BE PLACES THAT MAKE OUT A BIT BETTER WITH UP TO THREE QUARTERS OF AN INCH POSSIBLE...LIKE PARTS OF HARLAN COUNTY. OTHERWISE...MOST PLACES WILL FALL IN THE QUARTER TO HALF INCH RANGE THROUGH SATURDAY MORNING. THE SHOWERS WILL LIKELY SLACKEN THROUGH THE DAY SATURDAY AS THE SFC LOW STARTS TO FALL APART AND THE UPPER SUPPORT WANES. THERE WILL STILL BE A THREAT OF LIGHT SHOWERS THROUGH THE NIGHT AND INTO SUNDAY MORNING...THOUGH...BUT QPF WILL LIKELY BE ALMOST NEGLIGIBLE...RUNNING AT A TENTH OF AN INCH OR LESS FOR MOST PLACES. GIVEN THE SATURATION THROUGH SUNDAY MORNING EXPECT FAIRLY UNIFORM TEMPERATURES AND A NARROW DIURNAL RANGE FOR THE BULK OF THE WEEKEND. USED THE SHORTBLEND INITIALLY FOR TEMPERATURES AND DEWPOINTS ONCE AGAIN...INTO THE FIRST PART OF THE DAY SATURDAY WITH THE SUPERBLEND TO FOLLOW THROUGH THE SUNDAY MORNING. DID MAKE SOME POINT BASED ADJUSTMENTS TO HIGHS AND LOWS THROUGH SATURDAY NIGHT. AS FOR POPS...ENDED UP SIMILAR TO A BLEND OF THE WETTER MAV AND DRIER MET MOS THROUGH THE PERIOD. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 350 PM EDT FRI SEP 25 2015 UPPER LEVEL LOW THAT RETROGRADES EAST THIS WEEKEND WILL EVENTUALLY BECOME MORE DIFFUSE AS WE MOVE INTO SUNDAY. AFTER THIS WEAK HEIGHT RISES OCCURS AHEAD OF MID WEEK TROUGHING. THE MODELS CONTINUE TO DIVERGE AS WE MOVE THROUGH THE LONG TERM PERIOD IN RELATION TO HEIGHTS AND OVERALL PATTERN. THE ECMWF WANTS TO ESTABLISH A DEEPER TROUGH...WHILE THE GFS REMAINS MUCH FLATTER WITH THE PATTERN. THIS OF COURSE WILL INTRODUCE ADDITIONAL COMPLICATIONS TO THE SURFACE. HOWEVER WOULD SEEM LIKE SURFACE FEATURES WILL LACKING THROUGH THE PERIOD...THEREFORE THE WEAKER WAVES WILL BE THE BEST SUPPORT. RIGHT NOW WILL LEAN TOWARD THE BLEND JUST GIVEN THAT CONFIDENCE REMAINS LOWER THROUGH THE LONG TERM PERIOD. BEST CHANCES OF RAIN LOOK TO BE TUESDAY THROUGH WEDNESDAY TIME FRAME WITH UPPER SHORTWAVE AND ENERVATED FRONT WEDNESDAY. TEMPERATURES THROUGH THE PERIOD WILL BE NEAR NORMAL...HOWEVER DEPENDING ON THE DEPTH OF THE TROUGHING TOWARD LATE NEXT WEEK COULD BRING TEMPS TO BELOW NORMAL VALUES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 210 PM EDT FRI SEP 25 2015 MOISTURE CONTINUES TO STREAM INTO EASTERN KENTUCKY...CROSSING THE APPALACHIANS FROM THE ATLANTIC. THE LOWER LEVELS ARE STARTING TO SATURATE MORE EFFECTIVELY. AS A RESULT...MVFR/IFR CEILINGS WILL START TO BUILD DOWN THROUGH LATE AFTERNOON HOURS. STILL SOME QUESTION AS TO HOW LOW CIGS GET WITH THE RAIN THIS EVENING...WILL GO WITH LOWER VALUES...THOUGH...SIMILAR TO GUIDANCE ONCE INSOLATION IS NO LONGER AN ASSET. LIGHT...TO OCCASIONALLY MODERATE...RAIN SHOWERS WILL LIKELY BE SEEN THROUGHOUT THE BULK OF THE AVIATION PERIOD. DO NOT EXPECT CIGS TO IMPROVE MUCH UNTIL DAWN SATURDAY WITH SUNRISE AND SOME RESULTANT STRONGER EAST TO SOUTHEAST...DOWNSLOPE...FLOW. IN GENERAL...WINDS WILL BE FROM THE NORTHEAST TO EAST AT 5 TO 10 KTS FOR MUCH OF THE PERIOD...WITH OCCASIONAL GUSTS UP TO 15 KTS POSSIBLE AT SITES LIKE SYM AND SJS THIS AFTERNOON AND INTO THE FIRST PART OF THE EVENING. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GREIF LONG TERM...DJ AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
345 PM EDT FRI SEP 25 2015 .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 345 PM EDT FRI SEP 25 2015 18Z SFC ANALYSIS SHOWS LOW PRESSURE SPREADING NORTH INTO KENTUCKY BENEATH A DEVELOPING UPPER LOW. THIS IS SUPPORTING WAVES OF LIGHT TO MODERATE SHOWERS WORKING EAST TO WEST THROUGH EASTERN KENTUCKY. SO FAR...THE MORE SUBSTANTIAL RAIN HAS BEEN HELD UP OVER MUCH OF THE AREA DUE TO INITIAL DRY AIR AND DOWNSLOPING ON EAST TO NORTHEAST WINDS COMING OFF THE HIGHER TERRAIN. THE CLOUDS AND RAIN HAVE KEPT TEMPERATURES CAPPED THIS DAY WITH READINGS CURRENTLY IN THE LOW TO MID 60S THROUGHOUT EAST KENTUCKY. THE INCREASING SHOWERS HAVE HELPED TO SATURATE MUCH OF THE AREA WITH LOW 60S ACROSS SOUTHEAST PARTS OF THE CWA WHILE MID AND LOW 50S ARE NOTED TO THE NORTHWEST. WINDS...MEANWHILE...ARE GENERALLY FROM THE EAST AT 5 TO 10 KTS WITH OCCASIONAL GUSTS TO 15 KTS. THE MODELS REMAIN IN PRETTY GOOD AGREEMENT ALOFT AS THEY ALL DEPICT A CLOSED LOW FORMING OVER THE TENNESSEE VALLEY...AMID A REGION OF HIGH HEIGHTS...INTO SATURDAY MORNING. THIS UPPER LOW WILL THEN DRIFT NORTH INTO KENTUCKY THROUGH SUNDAY MORNING WHILE AMPLE AMOUNTS OF ENERGY SWIRLS AROUND ITS CENTER. THIS LOW WILL COMMENCE FILLING FOR THE LATTER PART OF THE SHORT TERM PERIOD... LESSENING ITS IMPACT ON SENSIBLE WEATHER FOR THE JKL CWA. GIVEN THE SIMILARITIES AMONG THE MODELS HAVE AGAIN FAVORED THE HIGHER RESOLUTION ONES LIKE THE RAP13 AND HRRR FOR WEATHER SPECIFICS... ALONG WITH THE NAM12 FROM LATER SATURDAY INTO SUNDAY MORNING. SENSIBLE WEATHER WILL FEATURE WAVES OF LIGHT TO MODERATE SHOWERS PUSHING ACROSS EAST KENTUCKY THROUGH THE NIGHT. THESE WILL STILL BE SOMEWHAT LIMITED BY DOWNSLOPING...BUT EVEN SO THERE WILL BE PLACES THAT MAKE OUT A BIT BETTER WITH UP TO THREE QUARTERS OF AN INCH POSSIBLE...LIKE PARTS OF HARLAN COUNTY. OTHERWISE...MOST PLACES WILL FALL IN THE QUARTER TO HALF INCH RANGE THROUGH SATURDAY MORNING. THE SHOWERS WILL LIKELY SLACKEN THROUGH THE DAY SATURDAY AS THE SFC LOW STARTS TO FALL APART AND THE UPPER SUPPORT WANES. THERE WILL STILL BE A THREAT OF LIGHT SHOWERS THROUGH THE NIGHT AND INTO SUNDAY MORNING...THOUGH...BUT QPF WILL LIKELY BE ALMOST NEGLIGIBLE...RUNNING AT A TENTH OF AN INCH OR LESS FOR MOST PLACES. GIVEN THE SATURATION THROUGH SUNDAY MORNING EXPECT FAIRLY UNIFORM TEMPERATURES AND A NARROW DIURNAL RANGE FOR THE BULK OF THE WEEKEND. USED THE SHORTBLEND INITIALLY FOR TEMPERATURES AND DEWPOINTS ONCE AGAIN...INTO THE FIRST PART OF THE DAY SATURDAY WITH THE SUPERBLEND TO FOLLOW THROUGH THE SUNDAY MORNING. DID MAKE SOME POINT BASED ADJUSTMENTS TO HIGHS AND LOWS THROUGH SATURDAY NIGHT. AS FOR POPS...ENDED UP SIMILAR TO A BLEND OF THE WETTER MAV AND DRIER MET MOS THROUGH THE PERIOD. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 425 AM EDT FRI SEP 25 2015 THE EXTENDED PORTION OF THE FORECAST BEGINS ON SATURDAY NIGHT WITH THE BROAD UPPER LEVEL RIDGE STILL OVER MUCH OF THE EASTERN TWO- THIRDS OF THE CONUS. THE JET AND MAIN FLOW REMAIN DISPLACED TO THE NORTH ALONG THE THE CANADIAN BORDER. MEANWHILE...OVER THE SOUTHEAST A CLOSED TROPICAL LOW WILL SLOWLY TRACK WEST THROUGH THE TN VALLEY AND THEN NORTH THROUGH THE OH VALLEY BEFORE FINALLY GETTING CAUGHT UP IN THE FLOW AND SWEPT OFF TO THE EAST THROUGH THE GREAT LAKES ON MONDAY. DURING THE TUESDAY THROUGH THURSDAY TIME FRAME...THE UPPER LEVEL PATTERN BEGINS TO SHIFT AS A BROAD LONGWAVE TROUGH BEGINS TO DESCEND ON THE EASTERN CONUS. THE TROUGH PUSHES THROUGH THE OH VALLEY BY THE WEDNESDAY TO THURSDAY TIME FRAME AS THE PATTERN SHIFTS TO A STRONG RIDGE OVER THE WEST AND DEEPENING TROUGH OVER THE EAST. CLOSER TO THE SURFACE...SATURDAY NIGHT THROUGH SUNDAY WILL FEATURE THE MEANDERING TROPICAL LOW DRIFTING THROUGH THE OHIO VALLEY. INSTABILITY THOUGH WILL BE AT A MINIMUM AS SHOWERS ARE EXPECTED THROUGH MONDAY. THIS FLOW FROM THE SOUTHEAST WILL CONTINUE AS A FRONT WILL PUSH IN FROM THE NORTHWEST ON WEDNESDAY. THIS WILL BE THE BEST INSTABILITY MOVING THROUGH BUT KEPT IN MOSTLY SHOWERS FOR NOW. OVERALL...THE SUPERBLEND RESULTS AND TREND POINT TO SOME SLIGHT TO LOW CHANCE POPS THROUGH THE EXTENDED WITH LITTLE CHANCE OF ANY THUNDER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 210 PM EDT FRI SEP 25 2015 MOISTURE CONTINUES TO STREAM INTO EASTERN KENTUCKY...CROSSING THE APPALACHIANS FROM THE ATLANTIC. THE LOWER LEVELS ARE STARTING TO SATURATE MORE EFFECTIVELY. AS A RESULT...MVFR/IFR CEILINGS WILL START TO BUILD DOWN THROUGH LATE AFTERNOON HOURS. STILL SOME QUESTION AS TO HOW LOW CIGS GET WITH THE RAIN THIS EVENING...WILL GO WITH LOWER VALUES...THOUGH...SIMILAR TO GUIDANCE ONCE INSOLATION IS NO LONGER AN ASSET. LIGHT...TO OCCASIONALLY MODERATE...RAIN SHOWERS WILL LIKELY BE SEEN THROUGHOUT THE BULK OF THE AVIATION PERIOD. DO NOT EXPECT CIGS TO IMPROVE MUCH UNTIL DAWN SATURDAY WITH SUNRISE AND SOME RESULTANT STRONGER EAST TO SOUTHEAST...DOWNSLOPE...FLOW. IN GENERAL...WINDS WILL BE FROM THE NORTHEAST TO EAST AT 5 TO 10 KTS FOR MUCH OF THE PERIOD...WITH OCCASIONAL GUSTS UP TO 15 KTS POSSIBLE AT SITES LIKE SYM AND SJS THIS AFTERNOON AND INTO THE FIRST PART OF THE EVENING. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GREIF LONG TERM...SHALLENBERGER AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
420 PM CDT FRI SEP 25 2015 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 419 PM CDT FRI SEP 25 2015 THE CLOUD COVER ACROSS CENTRAL MINNESOTA IS THE LAST BIT OF MID LEVEL CLOUDINESS TO DISSIPATE...WITH THE REST OF THE FORECAST AREA ALREADY HAVING DISSIPATED. WITH CONTINUED DRYING EXPECTED AND THE LOW TO OUR SOUTHWEST FILLING AND SINKING SOUTH...WHILE THE SURFACE HIGH EXPANDS EASTWARD INTO THE UPPER MIDWEST...SKIES ARE EXPECTED TO CLEAR THROUGH THE NEXT SEVERAL HOURS. THE CONCERN THEN BECOMES THE CHANCE FOR FOG EARLY TOMORROW MORNING. THE MOST SUSCEPTIBLE LOCATION IN OUR AREA FOR FOG LOOKS TO BE NEAR THE MILLE LACS LAKE AREA THROUGH ST CLOUD. THE HRRR AND HOPWRF AGREE THAT FOG THAT WILL ENGULF LAKE SUPERIOR TONIGHT WILL TRY AND EXPAND SOUTHWEST THROUGH THIS AREA. BEING LATE SEPTEMBER...IT TAKES A BIT MORE TIME TO BURN OFF THE FOG AS WE SAW THIS MORNING...BUT IT SHOULD BURN OFF A LITTLE MORE QUICKLY TOMORROW. THE PRESSURE GRADIENT WILL BEGIN TIGHTENING ESPECIALLY ACROSS WESTERN MN DURING THE AFTERNOON AS LOW PRESSURE STARTS PUSHING EAST THROUGH MONTANA. WITH A MIXING HEIGHT NEAR 850MB...HIGH TEMPS TOMORROW AFTERNOON UNDER PLENTIFUL SUNSHINE ABOUT 10 DEGREES ABOVE NORMAL...IN THE MID TO UPPER 70S. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 419 PM CDT FRI SEP 25 2015 BIG STORY FOR THE LONG TERM IS THE HEAT WAVE /FOR LATE SEPTEMBER STANDARDS/ THAT WILL CONTINUE THROUGH MONDAY BEFORE COOLER AIR ARRIVES TO END SEPTEMBER. CHANCES FOR LIGHT RAIN ARE BEGINNING TO LOOK BETTER MONDAY AFTERNOON THROUGH TUESDAY MORNING...WHILE RAINFALL CHANCES THE REST OF THE WEEK ARE STARTING TO LOOK A LITTLE MORE QUESTIONABLE. THE HEAT WILL BE ON RIGHT OUT THE GATE FOR SUNDAY AND MONDAY AS WE SIT OUT AHEAD OF A COLD FRONT. OUR WARMEST DAY LOOKS TO BE SUNDAY...THOUGH THE H85 THERMAL RIDGE WILL BE COMING THROUGH THE MPX AREA MONDAY NIGHT. STILL...MIX-DOWN HIGHS TO H85 WITH A SUPER ADIABATIC SFC LAYER CORRECTION OFF THE ECMWF YIELDED HIGHS BETWEEN 81 AND 84 ACROSS THE AREA. THIS IS A BIT HIGHER THAN WHAT MOST OF THE GUIDANCE SHOWS...SO MIXED THESE MIX DOWN TEMPS INTO THE COOLER CONSENSUS GRIDS TO GET HIGHS IN THE UPPER 70S/LOWER 80S ACROSS THE AREA. MONDAY WILL HAVE THE COLD FRONT MOVING ACROSS THE AREA AND WE WILL LIKELY SEE QUITE THE GRADIENT IN HIGHS MONDAY...WITH CLOUD COVER/SHOWERS DURING THE AFTERNOON LIKELY KEEPING CENTRAL MN IN THE 60S...WHILE PLACES FROM FAIRMONT TO EAU CLAIRE ON SOUTH WILL HAVE A CHANCE AT TOPPING OUT AT 80 ONE MORE TIME DUE TO THE LATER ARRIVAL OF THE FRONT AND ITS ASSOCIATED CLOUD COVER. AS FOR THE FRONT...PRECIP CHANCES WILL START INCREASING MONDAY AFTERNOON AND WILL LIKELY SEE RAIN SPREAD ACROSS MUCH OF THE AREA MONDAY NIGHT IS THE RIGHT ENTRANCE OF A JET STREAK MOVES ACROSS THE REGION. PRECIP WITH THIS FRONT LOOKS TO BE ALL POST FRONTAL WITHIN A ZONE OF FGEN...SO REMOVED THUNDER MENTION. AMOUNTS DO NOT LOOK ALL THAT GREAT...WITH AMOUNTS MAINLY UNDER A QUARTER OF AN INCH. BEHIND THIS FRONT WE WILL GET OUR FIRST HEALTHY CANADIAN HIGH SINCE THE 11TH OF SEPTEMBER. DEWPOINTS WILL LIKELY FALL BACK INTO THE 30S/40S TUESDAY INTO WEDNESDAY WHILE H85 TEMPS FALLING BACK TO AROUND +4C WILL KEEP HIGHS TUE/WED AROUND WHERE OUR LOWS WERE THIS MORNING /UPPER 50S TO MID 60S/. THESE COOLER TEMPS TO END SEPTEMBER WILL ENSURE THAT THE SEPTEMBER OF 1897 STAYS ATOP THE LIST OF WARMEST SEPTEMBERS OF ALL TIME IN THE TWIN CITIES...THOUGH THIS SEPTEMBER WILL STILL SAFELY STAY IN THE TOP 5 WARMEST SEPTEMBERS ON RECORD. AFTER TUESDAY...MODEL SPREAD INCREASES DRAMATICALLY FOR THE REST OF THE PERIOD. THE PROBLEM COMES WITH THE DEGREE WITH WHICH HOW FAR NORTH THE MAIN POLAR WRLIES RETREAT INTO CANADA. THE ECMWF TAKES THE WESTERLIES CLEAR UP INTO THE CANADIAN ARCTIC...WHICH RESULTS IN NUMEROUS HIGHS AND LOWS CLOSING OR EVEN COMPLETING CUTTING OFF ACROSS THE MID LATITUDES. THE GFS WANTS TO KEEP A LITTLE MORE FLOW FATHER SOUTH...RESULTING IN A SLIGHTLY LESS CHAOTIC PATTERN BY THE END OF THE WEEK THAN WHAT YOU SEE WITH THE ECMWF. AT ANY RATE...NOT MUCH CONFIDENCE IN THE FORECAST BEYOND WEDNESDAY...ESPECIALLY WITH RESPECT TO PRECIP CHANCES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1254 PM CDT FRI SEP 25 2015 LEFT OVER CLOUDINESS CONTINUES TO ERODE AS THE MAIN LOW FILLS IN NEAR NEBRASKA AND SAGS SOUTHWARD. MEANWHILE...HIGH PRESSURE NORTH OF THE GREAT LAKES WILL CONTINUE TO EXPAND SOUTH AND EAST...WITH AN WEST TO EAST ORIENTED AXIS MOVES OVERHEAD TONIGHT. MAIN CONCERN FOR THIS PERIOD IS POSSIBLE FOG TOMORROW MORNING. INDICATED SOME FOG AT ALL TAF SITES...MAINLY EXPECT MVFR OR VFR VIS...BUT WILL SEE IF DEW POINTS REMAIN ELEVATED THIS AFTERNOON OR NOT. IF THEY DO...HIGHER CROSSOVER TEMPS COULD MEAN IFR OR LIFR POTENTIAL FOG FOR SOME SPOTS...MAINLY EASTERN MN AND WESTERN WI. KMSP...LOOK FOR FOG EARLY TOMORROW...AGAIN MOST LIKELY MVFR OR VFR. OTHERWISE THE FORECAST IS VFR WITH EAST WINDS TURNING SOUTH TOMORROW AND INCREASING DURING THE AFTERNOON. /OUTLOOK FOR KMSP/ SUN...VFR. S WIND 10-15 KT. MON...VFR...POSSIBLE MVFR WITH SHRA LATE. WIND SW BCMG NW 5-10 KT. TUE...VFR. N WIND 5-10KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...SPD LONG TERM...MPG AVIATION...SPD
AREA FORECAST DISCUSSION
NWS DULUTH MN
318 PM CDT FRI SEP 25 2015 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 303 PM CDT FRI SEP 25 2015 WEAK HIGH PRESSURE HAS LED TO A DRY DAY ACROSS THE NORTHLAND...BUT PLENTY OF CLOUDS REMAINED OVER EXTREME NORTHERN WISCONSIN INTO MUCH OF NORTHEAST MINNESOTA. THE FLOW HAS BEEN WEAK AS SEEN WITH KDLH VWP ONLY SHOWING WINDS OF LESS THAN 10 KT AT 925MB/850MB. THERE WILL LIKELY BE SOME ADDITIONAL CLEARING OVER NORTHERN WISCONSIN INTO PARTS OF NORTHERN MINNESOTA...BUT THE RAP SUGGESTS LOWER CLOUDS WILL EXPAND AGAIN OVERNIGHT AS THE INVERSION STRENGTHENS. FOG WILL AGAIN BE POSSIBLE...ESPECIALLY ADJACENT TO LAKE SUPERIOR WHERE AN ONSHORE FLOW WILL CONTINUE. WE ISSUED A DENSE FOG ADVISORY FOR THE NORTH SHORE DOWN INTO THE TWIN PORTS REGION LATER THIS EVENING THROUGH SATURDAY MORNING. FOG MAY BE DENSE ELSEWHERE...ESPECIALLY IN AREAS THAT HAVE CLEARED OUT. LATER SHIFTS MAY NEED TO EXPAND THE ADVISORY. AS THE WEAK HIGH DEPARTS...THE GRADIENT WILL TIGHTEN AS A COLD FRONT/LOW PRESSURE SYSTEM MOVE INTO THE NORTHERN PLAINS. WE EXPECT THE CLOUDS/FOG TO SCOUR OUT MOST AREAS SATURDAY DUE TO STRONGER WINDS AND BETTER MIXING. THE NORTH SHORE WILL BE LAST TO SEE THE CLOUDS/FOG LIFT. SOUTHERLY WINDS WILL KEEP TEMPERATURES IN THE SIXTIES ALONG THE NORTH SHORE...BUT THE REST OF THE NORTHLAND WILL SEE HIGHS FROM 70 TO 76. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 303 PM CDT FRI SEP 25 2015 THE FOCUS IN THE LONG TERM IS ON PCPN ASSOCIATED WITH A COLD FRONT EXPECTED TO MOVE THROUGH THE NORTHLAND LATE SUNDAY AND MONDAY. THE LATEST GFS/GEM/ECMWF APPEAR TO BE IN GOOD AGREEMENT WITH THE TIMING OF THE FRONT AND PCPN...AND GENERALLY FASTER THAN THEIR EARLIER RUNS. THEREFORE...WAS CONFIDENT ENOUGH TO SPEED UP THE TIMING OF THE SHOWERS. STILL HAVE LOW CHANCES OF SHOWERS FOR TUESDAY NIGHT INTO THURSDAY...BUT MIGHT BE ABLE TO CUT BACK ON THIS WITH SUBSEQUENT FORECASTS SINCE THE MODELS ARE TRENDING TOWARDS HIGH PRESSURE AND A DRIER FORECAST FOR THIS THE MIDDLE OF THE WEEK. SUNDAY...THERE WILL BE SUNNY SKIES AND WARM SOUTHERLY FLOW ACROSS THE NORTHLAND AS A COLD FRONT IN CANADA APPROACHES THE NW FORECAST AREA. THE GFS BUFR AND NAM12 MODEL SOUNDINGS ARE IN GOOD AGREEMENT...HAVING 25 TO 30 KNOTS OF WIND SPEED IN THE MIXING LAYER IN BOTH MODELS. THEREFORE...CONFIDENT ENOUGH TO INCREASE THE WIND SPEEDS FOR THE AFTERNOON. WIDESPREAD WIND GUSTS OF 20 TO 25 MPH ARE LIKELY...AND MIGHT NEED TO INCREASE THIS TO NEARLY 30 MPH WITH SUBSEQUENT FORECASTS. IT WILL BE THE WARMEST DAY OF THE PERIOD...AND PROBABLY OF NEXT WEEK...WITH HIGHS REACHING THE MIDDLE 70S. LATE SUNDAY INTO MONDAY NIGHT...A COLD FRONT WILL PASS THROUGH THE NORTHLAND...GENERALLY FROM NW TO SE...DURING THIS TIME. THE FRONT WILL BEGIN TO BRING A SUBSTANTIAL DROP IN TEMPERATURE...WHICH WILL NOT BE FULLY REALIZED UNTIL TUESDAY. LIGHT RAIN IS POSSIBLE ALONG AND IN THE WAKE OF THE FRONT...ESPECIALLY ACROSS THE SOUTHERN FORECAST AREA LATE MONDAY AFTERNOON AND INTO MONDAY NIGHT. THE PREVIOUS FORECAST HAD THUNDER...BUT THE GFS AND SREF INDICATE LITTLE IF NO MOST UNSTABLE CAPE...SO FELT COMFORTABLE REMOVING THUNDER FROM THE FORECAST. TUESDAY...HIGH PRESSURE WILL SETTLE OVER THE NORTHLAND...RESULTING IN SUNNY SKIES...BUT TEMPERATURES WILL BE MUCH COOLER THAN JUST A COUPLE DAYS BEFORE. HIGHS WILL LIKELY BE IN THE 50S. THIS LATEST FORECAST HAS MIDDLE 50S OVER THE NORTH TO NEAR 60 OVER THE SOUTH...BUT MIGHT NEED TO LOWER THIS SEVERAL DEGREES. TUESDAY NIGHT...CLEAR SKIES AND VERY LIGHT WINDS WITH THE PASSING HIGH PRESSURE WILL PROMOTE STRONG RADIATIONAL COOLING. THE MODELS ARE TRENDING COLDER...AND MIGHT NEED TO LOWER THE FORECAST MUCH MORE THAN WE CURRENTLY HAVE IN THE FORECAST. NORTHERN MINNESOTA COULD FACE THE THREAT OF FROST. WEDNESDAY AND THURSDAY...THE HIGH PRESSURE WILL SHIFT EAST OF THE NORTHLAND AND LIGHT SOUTHERLY RETURN FLOW WILL DEVELOP ACROSS THE REGION. THIS WILL BRING A SLIGHT WARMING TREND INTO THURSDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1234 PM CDT FRI SEP 25 2015 THERE IS VERY CHALLENGING AND PERSISTENT FOG AND LIFR/IFR CLOUD COVER ACROSS NE MINNESOTA AND NW WISCONSIN AND THAT IS LINGERING INTO THE AFTERNOON...ESPECIALLY AT KDLH. HIGH PRESSURE WAS CENTERED NEAR JAMES BAY IN CANADA AS OF EARLY THIS AFTERNOON. THIS WAS RESULTING IN LIGHT EAST TO ESE FLOW ACROSS THE NORTHLAND. THIS FLOW CREATED FOG AND WIDESPREAD OVC LOW CLOUD COVER LAST NIGHT AND WHICH IS SLOWLY LIFTING AND ERODING THIS AFTERNOON. IT IS THE MOST PERSISTENT AT KDLH BECAUSE OF THE ADDED MOISTURE FROM LAKE SUPERIOR AND THE EFFECT OF THE TERRAIN OF THE FLOW LIFTING UP THE HILL. MORE INLAND AREAS ARE BEGINNING TO LIFT AND SCATTER WITH A TRANSITION TO MVFR/VFR. THIS TREND WILL CONTINUE THROUGH THE REST OF THE AFTERNOON. CONFIDENCE IS SIGNIFICANTLY LOWER FOR KDLH THAN OTHER TERMINALS. MAY NEED TO KEEP DELAYING THE IMPROVEMENT FORECAST FOR KDLH. BECOMING MORE AND MORE SKEPTICAL OF SIGNIFICANT IMPROVEMENT AT KDLH TODAY...BUT THE RAP13 AND HRRR STILL SUGGEST IMPROVEMENT BACK TO IFR/MVFR BY THE MIDDLE OR LATE AFTERNOON. HOWEVER...THAT IMPROVEMENT WILL BE SHORT LIVED. WHILE THE FOG AND LOW CLOUD COVER MAY BE LIMITED TO LAKE SUPERIOR AND THE HILLSIDE OF THE DULUTH LATE THIS AFTERNOON....SUNSET WILL LIKELY RESULT IN THE FOG AND LIFR/IFR CLOUD COVER SPREADING BACK INLAND TO MUCH OF THE NORTHLAND THIS EVENING AND OVERNIGHT. THE FOG AND LOW CLOUD COVER SHOULD LIFT MORE QUICKLY SATURDAY MORNING. IT WILL STILL TAKE THE LONGEST TO LIFT FROM DULUTH BECAUSE OF THE WIND FLOW FROM LAKE SUPERIOR. HAVE KDLH RETURNING TO VFR BY 15Z...BUT IT IS POSSIBLE IT COULD TAKE AS LONG AS 17Z. && .PRELIMINARY POINT TEMPS/POPS... DLH 52 71 56 74 / 0 0 0 0 INL 52 74 58 75 / 0 0 0 40 BRD 54 76 59 77 / 0 0 0 0 HYR 51 75 56 76 / 0 0 0 0 ASX 51 75 56 76 / 0 0 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...DENSE FOG ADVISORY FROM 10 PM THIS EVENING TO 10 AM CDT SATURDAY FOR WIZ001. MN...DENSE FOG ADVISORY FROM 10 PM THIS EVENING TO 10 AM CDT SATURDAY FOR MNZ020-021-037. LS...NONE. && $$ SHORT TERM...MELDE LONG TERM...GROCHOCINSKI AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS DULUTH MN
1250 PM CDT FRI SEP 25 2015 .UPDATE... ISSUED AT 1245 PM CDT FRI SEP 25 2015 FOG HAS LIFTED FOR MOST AREAS...BUT DENSE FOG REMAINED IN SPOTS AROUND THE TWIN PORTS. KDYT HAS RECENTLY REPORTED 1SM IN FOG...KSUW HAS RISEN TO 3/4SM AND KCOQ TO 1 1/2SM. WE THINK THERE WILL BE CONTINUED SLOW IMPROVEMENT...BUT THERE WILL LIKELY REMAIN AREAS OF FOG THROUGH THE AFTERNOON DUE TO THE MOIST EASTERLY UPSLOPE FLOW. THE LOWEST VSBYS WILL OCCUR MAINLY ALONG THE HIGHER TERRAIN AND OVER THE HILL IN DULUTH/PROCTOR. WE WILL LET THE DENSE FOG ADVISORY EXPIRE BUT MAY NEED TO ISSUE ANOTHER ONE THIS AFTERNOON FROM THE NORTH SHORE DOWN INTO THE TWIN PORTS AND POSSIBLE ALONG PORTIONS OF THE SOUTH SHORE FOR TONIGHT INTO SATURDAY MORNING. UPDATE ISSUED AT 1234 PM CDT FRI SEP 25 2015 UPDATED FOR THE NEW 18Z AVIATION DISCUSSION BELOW. UPDATE ISSUED AT 1048 AM CDT FRI SEP 25 2015 THE FOG HAS BEEN PERSISTENT THIS MORNING...ESPECIALLY AT THE HEAD OF LAKE SUPERIOR WHERE VISIBILITIES REMAIN AT OR BELOW A QUARTER MILE AS OF 1045 AM. WE WILL EXTEND THE DENSE FOG ADVISORY FOR A COUPLE MORE HOURS FOR THE TWIN PORTS REGION. MORE FOG IS EXPECTED TONIGHT. UPDATE ISSUED AT 840 AM CDT FRI SEP 25 2015 THE DENSE FOG ADVISORY HAS BEEN EXTENDED BOTH IN AREA AND TIME. WE ADDED COASTAL LAKE COUNTY TO THE ADVISORY AND EXTENDED IT TO 11 AM. A MOIST ONSHORE FLOW SHOULD KEEP DENSE FOG AROUND LONGER THAN AREAS FURTHER INLAND. WE EXPECT THE DENSE FOG IN THE BRAINERD LAKES...AITKIN...HINCKLEY AREAS TO LIFT SOME IN THE NEXT HOUR SO DID NOT EXTEND THE ADVISORY TO THOSE LOCATIONS. && .SHORT TERM...(TODAY THROUGH SATURDAY AFTERNOON) ISSUED AT 341 AM CDT FRI SEP 25 2015 MAIN CONCERNS IN THE SHORT TERM ARE FOCUSED AROUND THE AREAS OF FOG THIS MORNING...LOCALLY DENSE AROUND THE TWIN PORTS...AND THE PERSISTENT EAST WINDS OFF LAKE SUPERIOR KEEPING THE CLOUDS AROUND THROUGH MOST OF THE DAY AND TEMPERATURES ON THE COOL SIDE. A DENSE FOG ADVISORY REMAINS IN EFFECT UNTIL 9 AM THIS MORNING. WEAK RIDGE OF HIGH PRESSURE ALOFT WILL CONTINUE ACROSS THE UPPER MIDWEST AND WRN GREAT LAKES AREA TODAY AS A LINGERING SFC LOW OVER WRN IA SLIDES TO THE SOUTH AND HIGH PRESSURE AT THE SURFACE BEGINS TO BUILD ACROSS THE NORTHLAND. QUIET WEATHER CONDITIONS WILL PERSIST TODAY WITH MORNING FOG LIFTING IN THE LATE MORNING AND AFTERNOON...BUT WITH SKIES REMAINING MOSTLY CLOUDY THROUGH THE DAY. THE SFC HIGH OVER HUDSON BAY AND AN EXTENSION OF THIS RIDGE INTO MN/WI WILL KEEP THE E/NE WINDS GOING THROUGH THE NEXT 24 HOURS. THE NEXT TROUGH WILL SLIDE INTO THE NRN ROCKIES ON SATURDAY AND ENHANCE A PRESSURE GRADIENT ACROSS NRN MN. THIS GRADIENT WILL INDUCE A STIFF SOUTH WIND OVER NE MN SAT AFTERNOON. HOWEVER...WITH THE SFC RIDGE OVER THE WRN GREAT LAKES EAST WINDS WILL CONTINUE ACROSS WRN LAKE SUPERIOR. TEMPERATURES TODAY WILL WARM INTO THE MID 70S INLAND AWAY FROM LS. HOWEVER WITH THE LIGHT EAST WINDS OVER THE LAKE...TEMPERATURES AROUND THE PERIPHERY OF SUPERIOR WILL REMAIN IN THE 60S. WINDS WILL BECOME NEAR CALM TONIGHT AND AS CLOUD COVER DIMINISHES...TEMPERATURES MAY FALL INTO THE MID/UPPER 40S AND LOWER 50S. THE IMPACT FROM LAKE WINDS ON SATURDAY WILL BE LESS AS TEMPERATURES WARM INTO THE 70S ACROSS MUCH OF THE NORTHLAND. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 341 AM CDT FRI SEP 25 2015 THE WARM WEATHER WILL CONTINUE SATURDAY NIGHT AND SUNDAY...AS STRONG WAA CONTINUES IN THE WARM SECTOR AHEAD OF A LOW PRESSURE SYSTEM AND STRONG COLD FRONT. THE FRONT IS EXPECTED TO REACH THE INTERNATIONAL FALLS AREA BY 00Z MONDAY. SOME PRE FRONTAL SHOWERS WILL BE POSSIBLE ACROSS THE NORTHERN PORTION OF THE CWA...BUT WILL PROBABLY ONLY REACH THE FAR NORTH ON SUNDAY AFTERNOON. THE CHANCE OF SHOWERS WILL THEN PROGRESS SOUTHWARD ACROSS THE NORTHLAND SUNDAY NIGHT AND MONDAY. THE GFS IS INDICATING THE MOST QPF WITH THE EVENT...ALTHOUGH COVERAGE WILL PROBABLY STILL BE IN THE CHANCE/SCATTERED CATEGORY. MUCH COOLER WEATHER IS EXPECTED TO SETTLE INTO THE NORTHLAND BY MID WEEK...AS UPPER LEVEL HEIGHTS FALL AND HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES. THE GFS IS TRYING TO BRING A GOOD DEAL OF QPF TO THE UPPER MIDWEST ON WEDNESDAY NIGHT AND THURSDAY...BUT THE ECMWF IS MUCH DIFFERENT DURING THIS TIME FRAME. THE ECMWF SHOWS BUILDING HEIGHTS AND DRY WEATHER FOR THURSDAY...WHILE THE GFS HAS A WELL PRONOUNCED SHORTWAVE TROUGH EMBEDDED IN GENERAL NW FLOW. AS A RESULT...CONFIDENCE IN ANY PARTICULAR SOLUTION IS FAIRLY LOW DURING THE MID TO LATTER PART OF THE WORK WEEK. HIGHS WILL RANGE FROM THE 70S ON SUNDAY...TO THE 50S AND 60S FOR THE REMAINDER OF THE LONG TERM. LOWS WILL RANGE FROM THE 30S TO 40S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1234 PM CDT FRI SEP 25 2015 THERE IS VERY CHALLENGING AND PERSISTENT FOG AND LIFR/IFR CLOUD COVER ACROSS NE MINNESOTA AND NW WISCONSIN AND THAT IS LINGERING INTO THE AFTERNOON...ESPECIALLY AT KDLH. HIGH PRESSURE WAS CENTERED NEAR JAMES BAY IN CANADA AS OF EARLY THIS AFTERNOON. THIS WAS RESULTING IN LIGHT EAST TO ESE FLOW ACROSS THE NORTHLAND. THIS FLOW CREATED FOG AND WIDESPREAD OVC LOW CLOUD COVER LAST NIGHT AND WHICH IS SLOWLY LIFTING AND ERODING THIS AFTERNOON. IT IS THE MOST PERSISTENT AT KDLH BECAUSE OF THE ADDED MOISTURE FROM LAKE SUPERIOR AND THE EFFECT OF THE TERRAIN OF THE FLOW LIFTING UP THE HILL. MORE INLAND AREAS ARE BEGINNING TO LIFT AND SCATTER WITH A TRANSITION TO MVFR/VFR. THIS TREND WILL CONTINUE THROUGH THE REST OF THE AFTERNOON. CONFIDENCE IS SIGNIFICANTLY LOWER FOR KDLH THAN OTHER TERMINALS. MAY NEED TO KEEP DELAYING THE IMPROVEMENT FORECAST FOR KDLH. BECOMING MORE AND MORE SKEPTICAL OF SIGNIFICANT IMPROVEMENT AT KDLH TODAY...BUT THE RAP13 AND HRRR STILL SUGGEST IMPROVEMENT BACK TO IFR/MVFR BY THE MIDDLE OR LATE AFTERNOON. HOWEVER...THAT IMPROVEMENT WILL BE SHORT LIVED. WHILE THE FOG AND LOW CLOUD COVER MAY BE LIMITED TO LAKE SUPERIOR AND THE HILLSIDE OF THE DULUTH LATE THIS AFTERNOON....SUNSET WILL LIKELY RESULT IN THE FOG AND LIFR/IFR CLOUD COVER SPREADING BACK INLAND TO MUCH OF THE NORTHLAND THIS EVENING AND OVERNIGHT. THE FOG AND LOW CLOUD COVER SHOULD LIFT MORE QUICKLY SATURDAY MORNING. IT WILL STILL TAKE THE LONGEST TO LIFT FROM DULUTH BECAUSE OF THE WIND FLOW FROM LAKE SUPERIOR. HAVE KDLH RETURNING TO VFR BY 15Z...BUT IT IS POSSIBLE IT COULD TAKE AS LONG AS 17Z. && .PRELIMINARY POINT TEMPS/POPS... DLH 63 51 73 55 / 10 0 0 0 INL 69 52 74 57 / 10 0 0 10 BRD 74 53 76 57 / 0 0 0 0 HYR 74 51 75 55 / 10 0 0 0 ASX 67 51 77 54 / 0 0 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...DENSE FOG ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR WIZ001. MN...DENSE FOG ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR MNZ037. LS...NONE. && $$ UPDATE...MELDE SHORT TERM...TENTINGER LONG TERM...DAP AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1234 PM CDT FRI SEP 25 2015 .UPDATE... ISSUED AT 1234 PM CDT FRI SEP 25 2015 UPDATED FOR THE NEW 18Z AVIATION DISCUSSION BELOW. UPDATE ISSUED AT 1048 AM CDT FRI SEP 25 2015 THE FOG HAS BEEN PERSISTENT THIS MORNING...ESPECIALLY AT THE HEAD OF LAKE SUPERIOR WHERE VISIBILITIES REMAIN AT OR BELOW A QUARTER MILE AS OF 1045 AM. WE WILL EXTEND THE DENSE FOG ADVISORY FOR A COUPLE MORE HOURS FOR THE TWIN PORTS REGION. MORE FOG IS EXPECTED TONIGHT. UPDATE ISSUED AT 840 AM CDT FRI SEP 25 2015 THE DENSE FOG ADVISORY HAS BEEN EXTENDED BOTH IN AREA AND TIME. WE ADDED COASTAL LAKE COUNTY TO THE ADVISORY AND EXTENDED IT TO 11 AM. A MOIST ONSHORE FLOW SHOULD KEEP DENSE FOG AROUND LONGER THAN AREAS FURTHER INLAND. WE EXPECT THE DENSE FOG IN THE BRAINERD LAKES...AITKIN...HINCKLEY AREAS TO LIFT SOME IN THE NEXT HOUR SO DID NOT EXTEND THE ADVISORY TO THOSE LOCATIONS. && .SHORT TERM...(TODAY THROUGH SATURDAY AFTERNOON) ISSUED AT 341 AM CDT FRI SEP 25 2015 MAIN CONCERNS IN THE SHORT TERM ARE FOCUSED AROUND THE AREAS OF FOG THIS MORNING...LOCALLY DENSE AROUND THE TWIN PORTS...AND THE PERSISTENT EAST WINDS OFF LAKE SUPERIOR KEEPING THE CLOUDS AROUND THROUGH MOST OF THE DAY AND TEMPERATURES ON THE COOL SIDE. A DENSE FOG ADVISORY REMAINS IN EFFECT UNTIL 9 AM THIS MORNING. WEAK RIDGE OF HIGH PRESSURE ALOFT WILL CONTINUE ACROSS THE UPPER MIDWEST AND WRN GREAT LAKES AREA TODAY AS A LINGERING SFC LOW OVER WRN IA SLIDES TO THE SOUTH AND HIGH PRESSURE AT THE SURFACE BEGINS TO BUILD ACROSS THE NORTHLAND. QUIET WEATHER CONDITIONS WILL PERSIST TODAY WITH MORNING FOG LIFTING IN THE LATE MORNING AND AFTERNOON...BUT WITH SKIES REMAINING MOSTLY CLOUDY THROUGH THE DAY. THE SFC HIGH OVER HUDSON BAY AND AN EXTENSION OF THIS RIDGE INTO MN/WI WILL KEEP THE E/NE WINDS GOING THROUGH THE NEXT 24 HOURS. THE NEXT TROUGH WILL SLIDE INTO THE NRN ROCKIES ON SATURDAY AND ENHANCE A PRESSURE GRADIENT ACROSS NRN MN. THIS GRADIENT WILL INDUCE A STIFF SOUTH WIND OVER NE MN SAT AFTERNOON. HOWEVER...WITH THE SFC RIDGE OVER THE WRN GREAT LAKES EAST WINDS WILL CONTINUE ACROSS WRN LAKE SUPERIOR. TEMPERATURES TODAY WILL WARM INTO THE MID 70S INLAND AWAY FROM LS. HOWEVER WITH THE LIGHT EAST WINDS OVER THE LAKE...TEMPERATURES AROUND THE PERIPHERY OF SUPERIOR WILL REMAIN IN THE 60S. WINDS WILL BECOME NEAR CALM TONIGHT AND AS CLOUD COVER DIMINISHES...TEMPERATURES MAY FALL INTO THE MID/UPPER 40S AND LOWER 50S. THE IMPACT FROM LAKE WINDS ON SATURDAY WILL BE LESS AS TEMPERATURES WARM INTO THE 70S ACROSS MUCH OF THE NORTHLAND. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 341 AM CDT FRI SEP 25 2015 THE WARM WEATHER WILL CONTINUE SATURDAY NIGHT AND SUNDAY...AS STRONG WAA CONTINUES IN THE WARM SECTOR AHEAD OF A LOW PRESSURE SYSTEM AND STRONG COLD FRONT. THE FRONT IS EXPECTED TO REACH THE INTERNATIONAL FALLS AREA BY 00Z MONDAY. SOME PRE FRONTAL SHOWERS WILL BE POSSIBLE ACROSS THE NORTHERN PORTION OF THE CWA...BUT WILL PROBABLY ONLY REACH THE FAR NORTH ON SUNDAY AFTERNOON. THE CHANCE OF SHOWERS WILL THEN PROGRESS SOUTHWARD ACROSS THE NORTHLAND SUNDAY NIGHT AND MONDAY. THE GFS IS INDICATING THE MOST QPF WITH THE EVENT...ALTHOUGH COVERAGE WILL PROBABLY STILL BE IN THE CHANCE/SCATTERED CATEGORY. MUCH COOLER WEATHER IS EXPECTED TO SETTLE INTO THE NORTHLAND BY MID WEEK...AS UPPER LEVEL HEIGHTS FALL AND HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES. THE GFS IS TRYING TO BRING A GOOD DEAL OF QPF TO THE UPPER MIDWEST ON WEDNESDAY NIGHT AND THURSDAY...BUT THE ECMWF IS MUCH DIFFERENT DURING THIS TIME FRAME. THE ECMWF SHOWS BUILDING HEIGHTS AND DRY WEATHER FOR THURSDAY...WHILE THE GFS HAS A WELL PRONOUNCED SHORTWAVE TROUGH EMBEDDED IN GENERAL NW FLOW. AS A RESULT...CONFIDENCE IN ANY PARTICULAR SOLUTION IS FAIRLY LOW DURING THE MID TO LATTER PART OF THE WORK WEEK. HIGHS WILL RANGE FROM THE 70S ON SUNDAY...TO THE 50S AND 60S FOR THE REMAINDER OF THE LONG TERM. LOWS WILL RANGE FROM THE 30S TO 40S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1234 PM CDT FRI SEP 25 2015 THERE IS VERY CHALLENGING AND PERSISTENT FOG AND LIFR/IFR CLOUD COVER ACROSS NE MINNESOTA AND NW WISCONSIN AND THAT IS LINGERING INTO THE AFTERNOON...ESPECIALLY AT KDLH. HIGH PRESSURE WAS CENTERED NEAR JAMES BAY IN CANADA AS OF EARLY THIS AFTERNOON. THIS WAS RESULTING IN LIGHT EAST TO ESE FLOW ACROSS THE NORTHLAND. THIS FLOW CREATED FOG AND WIDESPREAD OVC LOW CLOUD COVER LAST NIGHT AND WHICH IS SLOWLY LIFTING AND ERODING THIS AFTERNOON. IT IS THE MOST PERSISTENT AT KDLH BECAUSE OF THE ADDED MOISTURE FROM LAKE SUPERIOR AND THE EFFECT OF THE TERRAIN OF THE FLOW LIFTING UP THE HILL. MORE INLAND AREAS ARE BEGINNING TO LIFT AND SCATTER WITH A TRANSITION TO MVFR/VFR. THIS TREND WILL CONTINUE THROUGH THE REST OF THE AFTERNOON. CONFIDENCE IS SIGNIFICANTLY LOWER FOR KDLH THAN OTHER TERMINALS. MAY NEED TO KEEP DELAYING THE IMPROVEMENT FORECAST FOR KDLH. BECOMING MORE AND MORE SKEPTICAL OF SIGNIFICANT IMPROVEMENT AT KDLH TODAY...BUT THE RAP13 AND HRRR STILL SUGGEST IMPROVEMENT BACK TO IFR/MVFR BY THE MIDDLE OR LATE AFTERNOON. HOWEVER...THAT IMPROVEMENT WILL BE SHORT LIVED. WHILE THE FOG AND LOW CLOUD COVER MAY BE LIMITED TO LAKE SUPERIOR AND THE HILLSIDE OF THE DULUTH LATE THIS AFTERNOON....SUNSET WILL LIKELY RESULT IN THE FOG AND LIFR/IFR CLOUD COVER SPREADING BACK INLAND TO MUCH OF THE NORTHLAND THIS EVENING AND OVERNIGHT. THE FOG AND LOW CLOUD COVER SHOULD LIFT MORE QUICKLY SATURDAY MORNING. IT WILL STILL TAKE THE LONGEST TO LIFT FROM DULUTH BECAUSE OF THE WIND FLOW FROM LAKE SUPERIOR. HAVE KDLH RETURNING TO VFR BY 15Z...BUT IT IS POSSIBLE IT COULD TAKE AS LONG AS 17Z. && .PRELIMINARY POINT TEMPS/POPS... DLH 63 51 73 55 / 10 0 0 0 INL 69 52 74 57 / 10 0 0 10 BRD 74 53 76 57 / 0 0 0 0 HYR 74 51 75 55 / 10 0 0 0 ASX 67 51 77 54 / 0 0 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...DENSE FOG ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR WIZ001. MN...DENSE FOG ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR MNZ037. LS...NONE. && $$ UPDATE...GROCHOCINSKI SHORT TERM...TENTINGER LONG TERM...DAP AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
231 PM CDT FRI SEP 25 2015 .SHORT TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 230 PM CDT FRI SEP 25 2015 UPPER SYSTEM THAT HAS BEEN RESPONSIBLE FOR DRENCHING RAINS THE PAST FEW DAYS WAS LOCATED OVER NORTHEAST KANSAS AT 19Z. THE SYSTEM WILL CONTINUE TO DRIFT SLOWLY SOUTH TONIGHT BEFORE DISSIPATING OVER THE SOUTHERN PLAINS BY SATURDAY MORNING. CLEARING SKIES ARE EXPECTED TO DEVELOP ACROSS EASTERN NEBRASKA AS THE SYSTEM MOVES OFF AND WEAKENS. LATEST RAP INDICATES LIMITED POTENTIAL FOR FOG SO HAVE REMOVED MENTION FROM FORECAST. GENERAL RIDGING THEN COVERS THE REGION FOR THE WEEKEND WITH FAIR SKIES AND WARM TEMPERATURES EXPECTED ACROSS THE FORECAST AREA. MODELS SIMILAR IN MOVING A COLD FRONT INTO THE REGION ON MONDAY STRETCHING FROM NORTHWEST IOWA INTO SOUTHWEST NEBRASKA BY MONDAY EVENING. LOOKS DRY FOR NOW AHEAD OF THE FRONT ON MONDAY WITH MODELS SHOWING POST FRONTAL SHOWERS FOR MONDAY NIGHT. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 230 PM CDT FRI SEP 25 2015 PERIODS OF SHOWERS AND THUNDERSTORMS LIKELY MONDAY NIGHT THROUGH TUESDAY AS THE FRONT PUSHES SOUTH. BEYOND THIS TIME THE FORECAST BECOMES LESS CONFIDENT AS GFS AND EURO SHOWING LARGE DIFFERENCES IN SOLUTIONS. EURO BUILDS A RIDGE ACROSS THE CENTRAL PLAINS INTO SOUTHERN CANADA WHILE GFS MAINTAINS A MORE ZONAL FLOW OVER THE MIDDLE OF THE COUNTRY. SMALL POPS COVER MOST OF THE EXTENDED PERIOD AFTER TUESDAY BASED ON MODEL BLENDS. && .AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1221 PM CDT FRI SEP 25 2015 SFC OBS THE LAST SEVERAL HOURS ARE SHOWING CONDITIONS ARE GRADUALLY IMPROVING OVER ERN NEB IN RESPONSE TO UPPER LVL DISTURBANCE/PCPN ACTIVITY SHIFTING WEST. EXPECT MVFR CIGS AT KOFK/KLNK TO GIVE WAY TO VFR IN THE NEXT COUPLE HOURS. KOMA HAS ALREADY IMPROVED TO VFR. OTHERWISE...NO SIGNIFICANT AVN ISSUES ANTICIPATED THE REST OF THE FCST PD. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...FOBERT LONG TERM...FOBERT AVIATION...DEE
AREA FORECAST DISCUSSION
NWS RALEIGH NC
330 PM EDT FRI SEP 25 2015 .SYNOPSIS...DEEP ATLANTIC MOISTURE PUMPING INTO THE REGION... BETWEEN STRONG CANADIAN HIGH PRESSURE TO OUR NORTH AND A LOW PRESSURE TROUGH NEAR THE SOUTHEAST COAST... WILL PRODUCE WET AND UNSETTLED CONDITIONS THROUGH SATURDAY. GRADUAL DRYING WILL TAKE PLACE SUNDAY AS THE HIGH PRESSURE AREA MOVES OUT OVER THE ATLANTIC. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 PM FRIDAY... BEST CHANCE OF RAIN THROUGH TONIGHT WILL REMAIN ALONG AND NORTH OF THE I40 CORRIDOR. THE UPPER LEVEL JET STREAK NOW EXTENDING FROM UPSTATE SC INTO SWRN NC WILL TRACK SLOWLY NORTHWARD AND WEAKEN THROUGH TONIGHT... AS THE MID LEVEL LOW TRACKS FROM NW GA NORTHWESTWARD INTO CENTRAL TN WITH LOWERING DPVA OVER CENTRAL NC. ASSOCIATED POTENT UPPER DIVERGENCE WILL SLOWLY DECREASE FROM SW TO NE BUT REMAIN ENHANCED OVER THE FAR NE CWA. WITH A STEADY INFLUX OF DEEP ATLANTIC MOISTURE INTO THIS AREA IN PARTICULAR (INCLUDING A STOUT 925-850 MB JETLET FROM THE ESE) PERSISTING INTO THE NIGHT AND PW VALUES REMAINING WELL ABOVE NORMAL... WILL RETAIN CATEGORICAL POPS IN THE NE CWA... ROUGHLY ALONG AND NORTH/NE OF A LINE FROM INT TO RDU TO GSB. WILL HAVE SLIGHTLY LOWER POPS TO THE SW OF HERE... WITH CONTINUED 295K-305K MOIST ISENTROPIC UPGLIDE AND HIGH MOISTURE INFLUX BUT WANING UPPER LEVEL SUPPORT. THE NSSL-WRF / HRRR / 3KM NAMRR ALL SUPPORT THIS TREND... BOOSTING CONFIDENCE. ADDITIONAL RAINFALL IN THE NE CWA COULD APPROACH AN INCH... BUT IN GENERAL THE WIDESPREAD RAINFALL AMOUNTS WILL BE LIGHT THROUGH TONIGHT... ALBEIT WITH ISOLATED HIGHER TOTALS MAINLY OVER THE NRN CWA. PRECIP SHOULD TREND TO MORE DRIZZLE THAN LIGHT RAIN OVER THE WRN/SRN CWA AS THE AIR DRIES OUT ABOVE -10C... NOTED BY THE RELATIVE DRY SLOT IN WATER VAPOR IMAGERY NOW OVER SC AND WRN NC. THICK CLOUD COVER WILL CONTINUE TO LIMIT THE DIURNAL TEMP RANGE... AND EXPECT LOWS TONIGHT TO BE JUST A CATEGORY OR TWO LOWER THAN CURRENT VALUES... FROM AROUND 60 TO THE UPPER 60S NW TO SE. -GIH && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... AS OF 325 PM FRIDAY... THE MID LEVEL LOW WILL TRACK FROM CENTRAL TN INTO WRN KY WHILE FILLING AND BECOMING ABSORBED INTO THE BROADER TROUGH EXTENDING FROM THE GREAT LAKES TO A DEVELOPING LOW OVER TX AND NE MEXICO. THIS WILL RESULT IN A TREND FROM A WEAK CYCLONIC MID LEVEL FLOW FROM THE S AND SE TO A MORE ANTICYCLONIC WEAK FLOW FROM THE WSW... WITH DPVA AND UPPER DIVERGENCE BOTH WEAKENING AND SHIFTING NORTH THROUGH SAT NIGHT. MODELS STILL DEPICT ABOVE NORMAL PW... FROM 1.5" NW TO OVER 2.0" EAST OF I95... AND MOIST UPGLIDE CONTINUES BUT TO A BIT LESSER DEGREE (DEPENDING ON THE MODEL)... SO THE THREAT OF PATCHY RAIN SHOULD PERSIST. OVERALL AMOUNTS AND SNAPSHOT COVERAGE SHOULD BE LOWER THAN TODAY HOWEVER... MEANING THAT WHILE MOST PLACES SHOULD SEE MEASURABLE RAIN... IT WON`T BE AS STEADY OR WITH QUITE THE INTENSITY AS WE`VE GOT TODAY. THE EXCEPTION MAY BE OVER COASTAL NC NEAR THE PERSISTENT INVERTED TROUGH... AND WELL TO OUR NW OVER THE SW VA MOUNTAINS WHERE TERRAIN UPLIFT WILL COME INTO PLAY... BUT OTHERWISE CENTRAL NC SHOULD SEE IMPROVING CONDITIONS IN TERMS OF RAINFALL. WILL HAVE CATEGORICAL POPS NE TO LIKELY SW TO START THE DAY... FOLLOWED BY A DOWNWARD TREND TO LIKELY NE AND GOOD CHANCE SW OF LIGHT RAIN AND DRIZZLE LATE SAT INTO SAT NIGHT. ALL INDICATIONS ARE THAT WE`LL STILL HAVE ABUNDANT LOW LEVEL MOISTURE IN PLACE... RESISTENT TO MIXING IN THE VERTICAL (LACK OF BOTH CONVECTION AND SUBSIDENCE) AND HORIZONTALLY (DUE TO THE IN SITU STABLE POOL BEING LOCKED IN OVER THE PIEDMONT/FOOTHILLS BY TERRAIN... THE COASTAL TROUGH... AND LIGHT SURFACE WINDS TO INHIBIT STIRRING). AS SUCH... MOSTLY CLOUDY SKIES WILL REMAIN THE RULE SAT AND SAT NIGHT WITH ONLY A LUCKY FEW (PROBABLY IN THE SE CWA) HAVING A CHANCE FOR SOME SUNSHINE). EXPECT HIGHS MINIMALLY HIGHER THAN TODAY... FROM THE MID 60S TO THE MID 70S NW TO SE. LOWS SAT NIGHT 60-68 WITH WIDESPREAD STRATUS AND LIGHT FOG. -GIH && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 320 PM FRIDAY... IT DOES NOT APPEAR THAT THAT THERE WILL BE A TREMENDOUS AMOUNT OF IMPROVEMENT IN THE SENSIBLE WEATHER ON SUNDAY WITH A SLIGHT IMPROVEMENT FINALLY ARRIVING ON MONDAY. WHILE THE CLOSED LOW ALOFT SHIFTS WEST AND HEIGHTS RISE SLIGHTLY OVER OUR REGION...THE AIRMASS OVER CENTRAL NC REMAINS MOIST THROUGH MONDAY WITH PW VALUES STILL AT OR ABOVE 1.75 INCHES WHICH SHOULD MAINTAIN CONSIDERABLE CLOUDINESS. WIDESPREAD PRECIPITATION SHOULD BE DIMINISHING WITH TIME AND SHIFTING NORTH AS THE BEST FORCING FOR ASCENT CONTINUES TO LIFT INTO THE MID ATLANTIC. WILL HOLD ONTO CHANCE POPS IN AN ARC FROM THE SOUTHERN COASTAL PLAIN NORTHWEST INTO THE VA BORDER COUNTIES WITH SLIGHT CHANCE POPS TO THE SOUTHWEST. HIGHS SUNDAY MAY BE A COUPLE OF DEGREES WARMER THAN SATURDAY BUT HAVE UNDERCUT GUIDANCE SEVERAL DEGREES...ESPECIALLY IN THE TRIAD WHERE A WEDGE AIRMASS REMAINS ESTABLISHED. SUNDAYS HIGHS WILL RANGE IN THE UPPER 60S TO UPPER 70S. HIGHS WILL MODERATE SOME ON MONDAY...ESPECIALLY IN THE NORTHWEST AND NORTHERN PIEDMONT WITH HIGHS IN THE MID 70S NORTHWEST TO LOWER 80S SOUTHEAST. MORNING LOWS ON MONDAY AND TUESDAY MORNING WILL RANGE IN THE 60S. A PERIOD OF SHORT WAVE RIDGING ALOFT ALONG WITH CENTRAL NC BEING LOCATED IN BETWEEN A DEPARTING COASTAL STORM SYSTEM AND A LOW PRESSURE AREA OVER THE GULF OF MEXICO SHOULD LEAD TO A PERIOD OF GENERALLY FAIR WEATHER FOR LATE MONDAY INTO LATE TUESDAY. WE SHOULD SEE SOME BREAKS IN THE OVERCAST WITH JUST A SLIGHT CHANCE OF A SHOWER. THIS SHOULD BE THE DRIEST PERIOD OF THE NEXT 7 DAYS. HIGHS IN THE MID 70S TO AROUND 80 LOOK GOOD. THE WESTERLIES BEGIN TO DROP SOUTH ON WEDNESDAY AND INTO THE LATE WEEK AS THE TROUGH AXIS EXTENDING FROM THE WESTERN GREAT LAKES TO THE WESTERN GULF OF MEXICO BEGINS SHIFTING EAST. THIS SHOULD RESULT IN ANOTHER PERIOD OF UNSETTLED WEATHER LATE WEDNESDAY INTO LATE THURSDAY. HPC GUIDANCE POPS HAVE TRENDED UP NOTABLY AND WE WILL FOLLOW THAT TREND WITH CHANCE POPS AND SLIGHTLY COOLER TEMPERATURES. FRIDAYS FORECAST APPEARS RATHER UNCERTAIN WITH THE NEW OPERATIONAL ECMWF DEVELOPING A SIGNIFICANT COASTAL LOW NEAR THE CAROLINA COAST THE SLOWLY MOVES NORTH ON FRIDAY. THE GFS AND THE GEFS ENSEMBLE MEMBERS DON`T SUPPORT THAT SOLUTION. WILL NEED TO WAIT AND SEE. - BLAES && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... AS OF 1255 PM FRIDAY... HIGH CONFIDENCE IN POOR (IFR CIGS AND MVFR TO OCNLY IFR VSBYS) DOMINATING THROUGH THE ENTIRE 24 HR TAF VALID PERIOD AT ALL FORECAST LOCATIONS. STRONG SURFACE HIGH PRESSURE CENTERED TO OUR NORTH OVER SE CANADA WILL DRIFT ACROSS THE ST LAWRENCE VALLEY TO NEW ENGLAND THROUGH SAT... WHILE A LOW PRESSURE TROUGH HOLDS NEAR THE SOUTHEAST AND CAROLINA COAST. THIS WILL CONTINUE TO GENERATE A DEEP ONSHORE- DIRECTED ATLANTIC-SOURCE FLOW WITH THICK LOW-BASED CLOUDS AND PERIODS OF MVFR TO IFR VSBYS MAINLY WITHIN RAIN BANDS. SUB-VFR CIGS ARE EXPECTED TO HOLD AREAWIDE THROUGH SAT AFTERNOON... ALTHOUGH THE RISK FOR IFR VSBYS WILL BE HIGHEST AT INT/GSO/RDU/RWI REST OF TODAY INTO THIS EVENING... AND WILL BE HIGHEST AT FAY LATE TONIGHT INTO SAT MORNING. PERIODIC LOW LEVEL WIND SHEAR IS POSSIBLE AT ALL SITES (SLIGHTLY HIGHER RISK AT FAY/RWI/RDU COMPARED TO INT/GSO) 00Z-14Z WITH LOW LEVEL JETTING AT 1500-2000 FT AGL FROM THE ENE AT AROUND 35- 40 KTS THIS EVENING LASTING THROUGH AT LEAST SUNRISE SAT. LOOKING BEYOND 18Z SAT: RAIN CHANCES AND COVERAGE -- AND THUS THE CHANCE FOR SUB-VFR VSBYS -- WILL CONTINUE TO SLOWLY DIMINISH FROM SOUTH TO NORTH THROUGH SAT NIGHT/SUN... BUT COVERAGE WILL REMAIN HIGHEST AT RDU/RWI WITH SLIGHTLY LOWER COVERAGE AT INT/GSO/FAY. THE CHANCE FOR SUB-VFR CIGS HOWEVER WILL REMAIN HIGH THROUGH AT LEAST SUN MORNING WITH HIGH PROBABILITIES OF MVFR TO IFR CIGS AT ALL SITES. IMPROVEMENT TO MAINLY MVFR AND POTENTIALLY TO LOW-END VFR IS EXPECTED BY SUN AFTERNOON. BUT IFR CIGS/VSBYS WITH SHALLOW STRATUS AND FOG SHOULD RETURN SUN NIGHT INTO MON MORNING. RAIN CHANCES WILL BE IN A RELATIVE LULL FROM LATE SUN THROUGH MON NIGHT. RAIN CHANCES MAY RETURN TUE INTO WED WITH SW FLOW ALOFT AHEAD OF A SURFACE COLD FRONT APPROACHING FROM THE NORTH... ALTHOUGH CONFIDENCE IN THIS IS LOWER THAN USUAL DUE TO MODEL DIFFERENCES... SO STAY TUNED. -GIH && .HYDROLOGY... AS OF 330 PM FRIDAY... WE`RE STILL GETTING RAINFALL REPORTS IN... BUT BY RADAR ESTIMATION... WE`VE HAD ANYWHERE FROM A QUARTER INCH TO AN INCH AND A HALF ACROSS CENTRAL NC... ENOUGH TO CAUSE SOME TRAFFIC SNARLS AND CONSIDERABLE PONDING OF WATER ON ROADS... BUT NO NOTABLE RIVER OR CREEK FLOODING. ADDITIONAL AMOUNTS COULD APPROACH AN INCH... MAINLY IN THE NRN CWA... BUT OVERALL ANY ADDITIONAL RAIN IS UNLIKELY TO CAUSE FLOODING CONCERNS. THE WET ROADS AND PONDING OF WATER HOWEVER WILL REMAIN A TRAVEL ISSUE THROUGH TONIGHT. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...HARTFIELD LONG TERM...BLAES AVIATION...HARTFIELD HYDROLOGY...HARTFIELD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1240 PM CDT FRI SEP 25 2015 .UPDATE... ISSUED AT 1233 PM CDT FRI SEP 25 2015 SATELLITE LOOPS SHOW THE STRATUS IS RAPIDLY BURNING OFF. SHOULD SEE MOSTLY SUNNY SKIES THIS AFTERNOON. TONIGHT GFS/NAM DEPICTS SOME SCATTERED SHOWERS ACROSS NORTHEAST MONTANA INTO SOUTHEAST SASK. WITH FLOW ALOFT SOUTHWEST TO NORTHEAST THE SHOWERS MOVE NORTHEAST AND REMAIN ALONG THE PERIPHERY OF THE STATE BOUNDARY. CURRENT FORECAST LOOKS GOOD. UPDATE ISSUED AT 1100 AM CDT FRI SEP 25 2015 THIS UPDATE TO EXPIRE THE DENSE FOG ADVISORY. UPDATE ISSUED AT 848 AM CDT FRI SEP 25 2015 WEBCAMS AND SURFACE OBSERVATIONS SHOW DENSE FOG CONTINUES IN MORTON COUNTY INCLUDING MANDAN...AND THE AREA EAST OF THE MISSOURI RIVER THROUGH THE JAMES RIVER VALLEY AND NORTH TO BOTTINEAU COUNTY. WILL KEEP THE ADVISORY GOING THROUGH 16Z. OTHERWISE USED SAT DATA TO MANUALLY ADJUST SKY CONDITION. STRATUS/FOG KEEPING HOURLY TEMPS COOL ACROSS THE JAMES RIVER VALLEY THIS MORNING. SHOULD SLOWLY CATCH UP WITH HIGH FORECAST AS CLOUDS DISSIPATE. UPDATE ISSUED AT 628 AM CDT FRI SEP 25 2015 BASED ON WEBCAMS AND SATELLITE THROUGH 1115 UTC...EXPANDED THE DENSE FOG ADVISORY INTO SIOUX...GRANT...MORTON...OLIVER AND MCLEAN COUNTIES THROUGH 16 UTC THIS MORNING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 243 AM CDT FRI SEP 25 2015 CURRENTLY...HIGH PRESSURE WAS CENTERED OVER HUDSON BAY...WITH A TROUGH OF LOW PRESSURE ALONG THE LEE OF THE ROCKIES. ANOTHER SURFACE LOW WAS OVER EASTERN NEBRASKA. LOW LEVEL MOISTURE MAINLY ASSOCIATED WITH THE LOW OVER NEBRASKA HAD SPREAD NORTHWARD INTO THE NORTHERN PLAINS. LOW CLOUDS AND FOG WAS COMMON FROM WISCONSIN AND MINNESOTA INTO THE EASTERN DAKOTAS AND SOUTHERN MANITOBA. THE LATEST ITERATIONS OF THE SHORT TERM HRRR MODEL CONTINUE TO INDICATE LOW CLOUDS AND FOG EXPANDING ACROSS CENTRAL AND EASTERN NORTH DAKOTA...MAINLY EAST OF THE MISSOURI RIVER IN SOUTH CENTRAL NORTH DAKOTA AND EAST OF MINOT/BOTTINEAU IN THE NORTH CENTRAL. ROLLA AND JAMESTOWN STATIONS HAVE REPORTED 1/4 MILE VISIBILITY...AND EXPECT THOSE CONDITIONS TO EXPAND WESTWARD. THUS WILL ISSUE A DENSE FOG ADVISORY ALONG AND EAST OF A LINE FROM BOTTINEAU TO BISMARCK TO THE LINTON AND STRASBURG AREAS. THIS INCLUDES THE TURTLE MOUNTAINS AND THE JAMES RIVER VALLEY. THE HRRR INDICATES THAT VISIBILITIES SHOULD IMPROVE QUICKLY AROUND 10AM-11AM...SO WILL HAVE THE ADVISORY IN EFFECT UNTIL 11 AM CDT. SOUTHERLY WINDS SHOULD INCREASE DURING THE LATE MORNING AND HELP MIX THE SURFACE WITH THE BOUNDARY LAYER. EXPECT IMPROVING CONDITIONS THIS AFTERNOON WITH PARTLY TO MOSTLY SUNNY SKIES AND HIGHS IN THE MID-UPPER 70S CENTRAL TO LOWER 80S WEST. SOUTHERLY WINDS REMAIN TONIGHT AHEAD OF AN APPROACHING SURFACE TROUGH...AND MODELS HINT AT RETURN OF LOW CLOUDS AND POSSIBLE FOG TO THE AREA. FOR NOW HAVE INCREASED THE FORECAST SKY COVER A BIT...AND WILL SEE HOW THE NEXT SET OF MODELS HANDLES THE LOW LEVEL MOISTURE FIELD. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 243 AM CDT FRI SEP 25 2015 A WARM UP INTO SATURDAY FOLLOWED BY A COOLING TREND EARLY NEXT WEEK HIGHLIGHTS THE EXTENDED FORECAST. THE 24/12 UTC NAEFS PERCENTILES DEPICT 850MB TEMPERATURES IN THE 99TH TO NEAR MAXIMUM PERCENTILES ACROSS SOUTHEAST MONTANA INTO SOUTHWEST NORTH DAKOTA SATURDAY AFTERNOON AHEAD OF A STRONG COLD FRONT FORECAST TO OVERTAKE THE AREA SATURDAY NIGHT INTO SUNDAY. THUS...INCREASED HIGHS INTO THE LOWER 90S WEST OF THE MISSOURI RIVER FOR SATURDAY...WHICH IS ABOVE THE 00 UTC GUIDANCE CONSENSUS. THEREAFTER...TEMPERATURES DECLINE AS THE SATURDAY UPPER LEVEL RIDGE BREAKS DOWN AND COOL HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE REGION MONDAY INTO TUESDAY. WIDESPREAD HIGHS IN THE 60S...AND POSSIBLY THE 50S ARE EXPECTED. MORNING FROST WILL BE POSSIBLE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1233 PM CDT FRI SEP 25 2015 TROUGH OF LOW PRESSURE ACROSS EASTERN MONTANA WILL MAINTAIN A DRY SOUTHERLY FLOW OF AIR ACROSS THE NORTHERN PLAINS. VFR AT ALL TAF SITES. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...JV LONG TERM...AYD AVIATION...WAA
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
142 PM EDT FRI SEP 25 2015 .SYNOPSIS... A WEAK AREA OF LOW PRESSURE OVER THE GULFSTREAM WILL SLOWLY MOVE NORTHEAST WHILE AN UPPER-LEVEL LOW JUST TO OUR WEST SLOWLY DISSIPATES THROUGH SATURDAY...RESULTING IN A DIMINISHING THREAT FOR MODERATE TO HEAVY RAINFALL. HOWEVER...CLOUDS AND LIGHT RAIN SHOWERS WILL PERSIST THROUGH SUNDAY BEFORE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS IS POSSIBLE TUESDAY THROUGH THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 140 PM...WIDESPREAD RAIN AND DRIZZLE WILL CONTINUE THRU THE DAY ALONG WITH CLOUDS AND GUSTY NELY WIND. CURRENT FCST HAS THIS IN PLACE...SO UPDATES MAINLY FOR CURRENT CONDITIONS. AS OF 1045 AM...STILL EXPECT WIDESPREAD RAIN AND DRIZZLE THRU THE DAY AS ISENTROPIC UPGLIDE AND ELY UPSLOPE LOW LEVEL FLOW CONTINUE ACROSS THE AREA. AN AREA OF HEAVIER RAINFALL OUTSIDE OF THE MTNS WILL MOVE NORTHWARD ACROSS THE CWFA TODAY...WHILE OFF AN ON HEAVIER RAINFALL CONTINUES ACROSS THE BLUE RIDGE AND MTNS. THAT SAID... PRECIP RATES DO NOT LOOK TO BE HIGH ENUF FOR WIDESPREAD FLOODING... BUT ISOLATED AREAS ARE POSSIBLE...ESPECIALLY IF ANY OF THE ELEVATED INSTABILITY COULD BE TAPPED INCREASING RATES. BREEZY NELY WINDS AND LOW CLOUDS...ALONG WITH THE RAIN AND DRIZZLE...WILL KEEP HIGHS BELOW NORMAL TODAY...WHICH HAS ALREADY BEEN ACCOUNTED FOR. 0630 AM UPDATE...NO MAJOR CHANGES NEEDED TO THE FCST. PRECIP SHIELD REMAINS FAIRLY WIDESPREAD. SOME CONVEC STREETS NOTED OVER THE MIDLANDS WITH DRY AIR ALOFT MIXING DOWN. THIS WILL LOWER POP POTENTIAL ACROSS THE SRN ZONES WITH SOME FILL-IN POSSIBLE AS MLVL Q/CONVG CROSSES OVERHEAD. THUS...WILL LEAVE POP GRADIENT AS IS IN THE GRIDS. RAINFALL REACHING THE ESCARPMENT IS NOT ENTIRELY ANCHORED AS LLVL FLOW REMAINS NE/LY BELOW 4 KFT. UPSLOPE ENHANCEMENT WILL BECOME MORE FAVORABLE THROUGH MID DAY. VERY GOOD MOISTURE FLUX ALIGNED IN DEEP ATL PWAT PLUME CONTINUES ACROSS THE FA THIS MORNING. HEAVIER RAINFALL RATES HAVE BEEN MAINTAINED SOUTH WITH THE UPSLOPE REGIONS REMAINING IN A RELATIVE MIN WITHIN NE/LY FLOW BELOW 4 KFT. EXPECT THIS TREND TO CONTINUE OVER THE NEXT FEW HRS AND HAVE ADJ QPF GRIDS TO FAVOR WRN UPSTATE AND NE GA ALONG WITH FAR SW BR THROUGH 12Z. THE SFC LOW WILL MOVE INLAND ACROSS THE SC LOW COUNTRY AND SE/RN GA TODAY THEN STALL OUT WHILE BECOMING LESS DEFINED. MEANWHILE...A NE/RN SFC RIDGE WILL CONTINUE TO BUILD IN TO SOME DEGREE. THE 12 KM NAM IS LESS AMPLIFIED WITH THE RIDGING THAN THE 20 KM GFS AND THIS WILL MAKE A BIG DIFFERENCE AS TO THE AMOUNT OF ISENT LIFT AND 300 K SAT PRES DEFS. WITH LESS LLVL FORCING AND THE RAP MODEL SHOWING RELATIVE DRYING ALOFT THROUGHOUT THE DAY...A CASE CAN BE MADE FOR A RELATIVELY LOW QPF RESPONSE OVER THE UPSTATE AND SRN NE GA. ALTHOUGH ISOL NAM CONVEC SOUTH WOULD ADD LOCALIZED HIGH AMOUNTS OF QPF OVER AREAS WITH THE BEST 24-PRECIP. THE GFS IS SOMEWHAT SIMILAR WITH THIS IDEA YET WITH NO GOOD CONVEC POTENTIAL AND A LITTLE MORE NON/MTN STRATIFORM QPF RESPONSE. IN ANY CASE...THE BEST AREA FOR PRECIP ACCUMS THROUGH THE PERIOD WILL BE ALONG THE BR WHERE AN INCH TO AN INCH AND A QUARTER COULD FALL THROUGH 12Z SAT AS LLVL FLOW BTW 3-5 KFT VEERS. THE NON/MTNS WILL GENERALLY SEE AROUND A HALF INCH DURING THIS TIME. HOWEVER...CONVEC WILL BE THE WILDCARD SOUTH IF ENUF MLVL DRYING OCCURS AS STATED ABOVE. THUS...LOCALIZED FLOODING CONCERNS ARE A LITTLE UNCERTAIN...BUT IF HYDRO BECOMES AN ISSUE...IT WILL BE ACROSS THE SRN ZONES AND/OR THE ERN FACING BR LATE TODAY. MAXES WILL BE HELD ABOUT 10-12 DEGREES BELOW NORMAL MOST LOCALES WITH MINS A COUPLE DEGREES ABOVE NORMAL. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 315 AM FRIDAY...MODELS STILL DISAGREE WITH HOW THE ONGOING RAIN EVENT WILL UNWIND ON SATURDAY AND SATURDAY NIGHT...ALTHO THERE IS GENERAL AGREEMENT IN SHIFTING THE DEEPER MOISTURE AND BETTER FORCING TO THE N BY SATURDAY AFTERNOON. EVEN THE NAM...WHICH WAS A HOLDOUT...NOW HAS THE BEST Q-CONVERGENCE AND UPPER DIVERGENCE ACROSS VA/WV BY 18Z SATURDAY. THE DEEP MOISTURE PLUME SHOULD ALSO BE DIRECTED UP ACROSS THE DELMARVA/TIDEWATER REGION BY THAT TIME AS WELL. THAT SUGGESTS WE SHOULD NOT HAVE MUCH OF A HEAVY PRECIP THREAT MUCH BEYOND 12Z SATURDAY...WHICH IS GOOD. THE PROBLEM IS MAINLY WITH LOW LEVEL MOISTURE AND FORCING... AND THE NAM STILL HAS MUCH MORE ISENTROPIC LIFT OVER THE NC PIEDMONT/FOOTHILLS AND A MORE EASTERLY FLOW AT 850MB DIRECTED AT THE NC MTNS. THUS...NO SURPRISE THAT THE NAM HOLDS ONTO PRECIP PRODUCTION ACROSS THOSE AREAS RIGHT THRU SUNDAY NIGHT. MEANWHILE...THE GFS OPENS UP MORE OF A HOLE ACROSS UPSTATE SC AND GRADUALLY ELIMINATES PRECIP FROM THERE TO THE POINT WHERE IT HAS MINIMAL PRECIP ACROSS THE MTNS FROM SATURDAY NIGHT ONWARD...AND IS BASICALLY DRY ELSEWHERE. THE ECMWF STILL OFFERS A DECENT COMPROMISE. THUS...WILL RAMP DOWN THE POP SATURDAY...AND THEN HOLD ONTO THE LIKELY NEAR THE NC BLUE RIDGE SATURDAY NIGHT WHERE THE LLVL FORCING WOULD BE BEST. POP WILL BE KEPT AT CHC ACROSS THE REST OF THE AREA. ON SUNDAY...THE CHANCE POP GETS PARED BACK TO THE MTNS WHERE ANY REMAINING LIFT WOULD BE THE BEST. THE REST OF THE FCST HAS TOKEN CHC/SLIGHT CHC POP UNTIL WE GET BETTER MODEL CONSENSUS. TEMPS WILL BE SEASONALLY COOL AS WE DEAL WITH THE REMNANTS OF THE COLD AIR DAMMING WEDGE. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 340 AM FRIDAY...HAVE TABLED THE MEDIUM RANGE FOR NOW DUE TO ONGOING FLOOD CONCERNS. NO CHANGES WERE MADE AT THIS TIME. REMAINDER OF PREVIOUS DISCUSSION... THE EXTENDED PERIOD BEGINS WITH THE WEEKEND RAINFALL EVENT ON THE WANE AND DRIER CONDITIONS BUILDING IN ACROSS THE FORECAST AREA. WHILE FLOW ALOFT WILL BE SOUTHERLY THANKS TO A CUT-OFF 500MB LOW OVER SOUTH TEXAS AND AN ANTICYCLONE OVER THE WESTERN SARGASSO SEA...SURFACE HIGH PRESSURE AND A LACK OF NOTABLE SHORTWAVES IN THE FLOW ALOFT SHOULD KEEP THE AREA MOSTLY DRY THROUGH MIDDAY TUESDAY. THEREAFTER...THERE IS GENERAL AGREEMENT THAT A LONGWAVE TROUGH WILL MOVE ACROSS THE NORTHERN HALF OF THE U.S. AND CANADA AND AN ASSOCIATED SURFACE LOW PRESSURE SYSTEM AND ATTENDANT COLD FRONT WILL APPROACH OUR AREA ON WEDNESDAY. BOTH THE GFS AND THE ECMWF ARE NOT EXCITED ABOUT NOTABLE RAINFALL AS A RESULT OF THE FRONTAL PASSAGE...HOWEVER...THE GFS CONTINUES TO BE BULLISH ON A MODEST BUT WELL-DEFINED SURFACE LOW MOVING NORTHWARD OVER THE CENTRAL GULF AND APPROACHING THE LOUISIANA COAST BY TUESDAY AFTERNOON. THE ECMWF WEAKENS THE LOW TO AN OPEN TROUGH OVER THE NORTHERN GULF. BOTH MODELS DO NOT BRING THE FEATURE INLAND...HOWEVER THE GFS KEEPS THE SOUTHERN APPALACHIANS IN A MOISTURE-RICH ENVIRONMENT WITH A TROPICAL CONNECTION TO THE CARIBBEAN AND EJECTS ROUNDS OR BANDS OF CONVECTIVE PRECIP NORTH FROM THE GULF LOW ACROSS THE DEEP SOUTH AND INTO OUR AREA BEGINNING TUESDAY EVENING AND LASTING THROUGH WEDNESDAY. THE ECMWF PERSISTS WITH WEAK NORTHEASTERLY FLOW ACROSS MUCH OF THE SOUTHEAST HEADING INTO THURSDAY. AT THIS TIME THE FORECAST MAINTAINS SLIGHT CHANCE TO CHANCE POPS DURING THE MID-WEEK PERIOD GIVEN THE DECENT MOISTURE THAT REMAINS IN PLACE FOLLOWING THE EVENT ENDING ON SUNDAY...THE ANTICIPATED FRONTAL PASSAGE...AND THE PERSISTENCE OF BOTH MODELS OVER THE PAST FEW RUNS OF SUGGESTING SOME ACTIVITY IN THE GULF MOVING TOWARDS THE COAST. NEVERTHELESS...BOTH THE ECMWF AND GFS AGREE THAT A STRONG 1028MB SURFACE HIGH BUILDS IN ACROSS THE NORTHEAST U.S. ON THE CONFLUENT SIDE OF THE UPPER-LEVEL LONGWAVE TROUGH AND WEDGES DOWN ACROSS MUCH OF THE SOUTHEAST U.S.... SIGNIFICANTLY DRYING US OUT THROUGH THE END OF THE PERIOD ON FRIDAY MORNING. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... AT KCLT AND ELSEWHERE...HIGH PRESSURE NOSED INTO THE AREA FROM THE NE WILL KEEP PERIODICALLY GUSTY NELY WINDS ACROSS THE AREA THRU THE PERIOD. KAVL THE EXCEPTION WHERE SELY WIND WILL PREVAIL DURING DAYLIGHT AND NLY WIND AT NITE. ELY LOW LEVEL FLOW AND DEEP MOISTURE MEANS IFR CIGS AND PERIODS OF LIGHT RAIN AND DRIZZLE WILL CONTINUE THRU THE PERIOD AS WELL. VSBY WILL BE VARIABLE...BUT SHUD BE MVFR FOR MOST OF THE PERIOD...WITH IFR POSSIBLE DURING ANY HEAVIER SHRA AND TOWARD DAYBREAK. VSBY SHUD IMPROVE BY NOON SAT...BUT IFR CIGS WILL CONTINUE. OUTLOOK...DEEP MOISTURE AND WIDESPREAD LIFT WILL LIKELY RESULT IN RESTRICTIVE CEILINGS AND PERIODICAL VISIBILITY RESTRICTIONS THRU THE DAY SATURDAY AND POSSIBLY THRU EARLY NEXT WEEK. CONFIDENCE TABLE... 17-23Z 23-05Z 05-11Z 11-12Z KCLT MED 71% HIGH 100% MED 66% HIGH 83% KGSP HIGH 100% HIGH 100% HIGH 89% HIGH 100% KAVL HIGH 100% HIGH 100% MED 66% HIGH 100% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 83% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 83% KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO/JMP NEAR TERM...RWH/SBK SHORT TERM...PM LONG TERM...JMP/PM AVIATION...RWH/SBK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
300 PM MDT FRI SEP 25 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 300 PM MDT FRI SEP 25 2015 UPPER LOW OVER THE NE/KS BORDER AREA EXPECTED TO DRIFT SLOWLY SOUTH OVERNIGHT. SOME LOW LEVEL MOISTURE AROUND THIS EVENING MAY SLIP BACK WESTWARD OVERNIGHT AND ALLOW FOR FOG TO REFORM YET AGAIN OVER THE LOWER AREAS OF THE PANHANDLE LATER TONIGHT BEFORE DISSIPATING SATURDAY MORNING. OTHERWISE WARM AND DRY WEATHER TO PERSIST OVER THE CWA SATURDAY THROUGH SUNDAY UNDER A SLOWLY WEAKENING UPPER RIDGE. A MODEST COOL FRONT MAY SLIP INTO CENTRAL WYOMING DURING THE DAY SUNDAY AS SHORT WAVE ENERGY MOVES ACROSS SOUTHERN CANADA WITH THE FRONT SAGGING ACROSS THE CWA SUNDAY NIGHT. NOT OUT OF THE QUESTION FOR A FEW SHOWERS OVER THE FAR NORTH PARTS OF THE CWA LATER SUNDAY BUT WILL NOT MENTION AT THIS TIME. TEMPS REMAINING QUITE WARM SATURDAY AND SUNDAY WITH A FEW RECORD HIGHS POSSIBLY BEING ATTAINED. .LONG TERM...(MONDAY THROUGH FRIDAY) ISSUED AT 300 PM MDT FRI SEP 25 2015 12Z MEDIUM MODELS ARE IN REASONABLE AGREEMENT TO START THE WORK WEEK WITH A UPPER RIDGE CENTERED OVER THE SOUTHWEST CONUS AND ACTIVE NORTHERN STREAM UPPER TROUGH OVER SOUTHERN CANADA. THE GFS AND ECMWF PUSH A SURFACE RIDGE SOUTHWARD INTO THE NORTH CENTRAL PLAINS...WITH THE LEADING EDGE OF THE COOLER AIRMASS MOVING SOUTH THROUGH SOUTHEAST WY AND NE PANHANDLE MONDAY AFTERNOON. HIGH TEMPERATURES MONDAY WILL BE WARMEST AHEAD OF THE FRONT WITH LOW TO MID 80S OVER SOUTHEAST WY PLAINS AND SOUTHERN NE PANHANDLE... AND 70S BEHIND THE FRONT. A SHORTWAVE COMBINED WITH LOW LEVEL UPSLOPE AND MOISTURE CONVERGENCE WILL PRODUCE ISOLATED TO SCATTERED SHOWER COVERAGE MONDAY NIGHT AND TUESDAY. THERE MAY BE ENOUGH CAPE FOR A FEW TSTORMS AS WELL. THE GFS LOOKS OVERDONE WITH ITS QPF AND SIDED WITH THE ECMWF. IT WILL BE COOLER TUESDAY WITH ISOLATED SHOWERS FAR NORTHEAST CWA AND SOUTHEAST WY MOUNTAINS. HIGHS TUESDAY WILL BE IN MID 60S TO MID 70S. MODEL DIFFERENCES APPEAR MID WEEK WITH THE ECMWF BUILDING THE UPPER RIDGE NORTH ALONG THE CONTINENTAL DIVIDE...WHILE THE GFS KEEPS THE RIDGE SUPPRESSED TO THE SOUTH AS A SERIES OF SHORTWAVES TRACK NORTHEAST FROM THE PACIFIC NORTHWEST INTO THE NORTHERN PLAINS. FAVORED THE DRIER AND WARMER WEST-NORTHWEST PATTERN WEDNESDAY WITH HIGH TEMPERATURES IN THE MID 70S TO LOWER 80S. THE FLOW ALOFT BACKS TO SOUTHWEST IN ADVANCE OF A DIGGING UPPER TROUGH TO THE WEST THURSDAY...WHICH WILL ADVECT SOME PACIFIC MOISTURE INTO SOUTHEAST WY THURSDAY AFTERNOON. KEPT SLIGHT CHANCE POPS FOR THE MOUNTAINS AND SOUTHEAST WY PLAINS AS WELL AS OVER EAST CENTRAL WY AND NORTHERN NE PANHANDLE INTO THURSDAY NIGHT. HIGHS THURSDAY WILL BE A FEW DEGREES COOLER WITH INCREASED CLOUD COVER. A PACIFIC FRONT WILL PUSH THROUGH THE CWA BY FRIDAY MORNING WITH A DRIER AND SLIGHTLY COOLER AIRMASS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1139 AM MDT FRI SEP 25 2015 IFR CEILINGS ARE ERODING FROM TOR TO BFF AND SOUTH TO SNY AT MIDDAY. EXPECT VFR/SKC ALL TERMINALS AFTER 19Z. WINDS WILL BE VARIABLE 10 KT OR LESS...EXCEPT WEST OF THE LARAMIE RANGE WHERE THEY WILL BE SOUTHWESTERLY 10 TO 15 KT. IDEAL CONDITIONS EXIST FOR LOW CEILINGS AND VISIBILITIES LATER THIS EVENING AND OVERNIGHT FOR WESTERN NE AND FAR SOUTHEAST WY PLAINS. TIMING OF IFR TO LIFR CONDITIONS BASED ON THE LATEST SREF AND HRRR MODELS. && .FIRE WEATHER... ISSUED AT 300 PM MDT FRI SEP 25 2015 CONCERNS EXPECTED TO REMAIN GENERALLY ON THE LOW SIDE INTO EARLY NEXT WEEK. THERE MAY BE SOME ELEVATED FIRE WEATHER CONDITIONS FOR SHORT PERIODS OF TIME SATURDAY AND SUNDAY AFTERNOON OVER FAR WESTERN AND NORTHWESTERN AREAS DUE TO SOME BREEZINESS...BUT WINDS LOOK LIKE THEY WILL REMAIN BELOW CRITICAL THRESHOLDS OVERALL. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...RE LONG TERM...MAJ AVIATION...MAJ FIRE WEATHER...RE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1146 AM MDT FRI SEP 25 2015 .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 345 AM MDT FRI SEP 25 2015 A QUIET WEATHER PERIOD WILL CONTINUE OVER THE NEXT SEVERAL DAYS WITH UPPER-LEVEL RIDGING IN PLACE. A MOIST LOW-LEVEL AIR MASS REMAINS IN PLACE WITH WIDESPREAD SURFACE DEW POINTS IN THE 40S/50S. LIGHT WINDS AND CLEAR SKIES HAVE ONCE AGAIN ALLOWED PATCHY FOG TO DEVELOP ACROSS THE NE PANHANDLE AND PLATTE RIVER VALLEY EXTENDING INTO SOUTHEASTERN WY. STRONG SUBSIDENCE SUGGESTS SUNNY SKIES WILL PREVAIL BEYOND ABOUT 15Z WHEN THE HRRR HINTS AT FOG STARTING TO ERODE. WE COULD VERY WELL SEE THIS AGAIN TONIGHT AS THE NAM SHOWS A RATHER ROBUST INCREASE IN BOUNDARY LAYER MOISTURE AFTER 03Z SAT VIA MOIST SOUTHEASTERLY LOW- LEVEL FLOW. INHIBITING FACTOR FOR FOG WOULD BE STRONGER WINDS OWING TO A HIGHER SURFACE PRESSURE GRADIENT THAN WE ARE SEEING ATTM...BUT NAM/GFS BUFKIT SOUNDINGS BOTH OFFER ENOUGH SUPPORT TO ADD PATCHY FOG TO THE GRIDS. IT STILL LOOKS VERY WARM THIS WEEKEND WITH H7 TEMPS IN THE +13 TO +15 DEG C RANGE ACROSS MOST OF THE CWA ON SAT/SUN. EXPECT TO SEE WIDESPREAD HIGHS IN THE 85-95 DEG F RANGE...WHICH MAY BE NEAR RECORD AT SOME SITES. AREAS ALONG AND WEST OF THE LARAMIE RANGE WILL SEE AFTERNOON HUMIDITIES BELOW 15 PERCENT EACH AFTERNOON...BUT MID- LEVEL FLOW IS NOT PARTICULARLY STRONG WITH A RIDGE AXIS PARKED OVER THE CENTRAL ROCKIES. STRONG MIXING WILL ALMOST UNDOUBTEDLY YIELD A FEW GUSTS AROUND 20-25 MPH...BUT OPTED NOT TO ISSUE ANY FIRE WEATHER HIGHLIGHTS AS ANY POTENTIAL FOR RED FLAG CONDITIONS WILL BE MARGINAL AT BEST. .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 345 AM MDT FRI SEP 25 2015 MONDAY WILL LIKELY BE THE WARMEST DAY OF THE EXTENDED PERIOD WITH STRONG RIDGING ALOFT AND 700MB TEMPS AROUND 12C. A WEAK COLD FRONT WILL MOVE ACROSS THE PLAINS ON MON NIGHT WITH WINDS BECOME EASTERLY BY TUESDAY. THE GFS CONTINUES TO BE MORE BULLISH WITH QPF ON TUESDAY AND TUESDAY NIGHT AS UPPER LEVEL DISTURBANCES INTERACT WITH THE LOW LEVEL UPSLOPE. THE ECMWF SHOWS LOW STRATUS TO THE EAST OF THE LARAMIE RANGE WITH DRIZZLE/LIGHT RAIN SHOWERS...HOWEVER DEEP LAYER UPWARD MOTION IS LACKING. HAVE 20 PERCENT POPS FROM TUESDAY INTO TUESDAY NIGHT WITH THE MODEL UNCERTAINTY STILL HIGH. THERE WILL BE A COOL DOWN FOR TUESDAY BEHIND THE FRONT. THE ECMWF SHOWS QUICKLY RISING HEIGHTS/TEMPS BY WED WHEREAS THE GFS HAS THE UPPER TROUGH AXIS MOVING OVERHEAD. WINDS THROUGHOUT THE LONG TERM WILL BE QUITE LIGHT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1139 AM MDT FRI SEP 25 2015 IFR CEILINGS ARE ERODING FROM TOR TO BFF AND SOUTH TO SNY AT MIDDAY. EXPECT VFR/SKC ALL TERMINALS AFTER 19Z. WINDS WILL BE VARIABLE 10 KT OR LESS...EXCEPT WEST OF THE LARAMIE RANGE WHERE THEY WILL BE SOUTHWESTERLY 10 TO 15 KT. IDEAL CONDITIONS EXIST FOR LOW CEILINGS AND VISIBILITIES LATER THIS EVENING AND OVERNIGHT FOR WESTERN NE AND FAR SOUTHEAST WY PLAINS. TIMING OF IFR TO LIFR CONDITIONS BASED ON THE LATEST SREF AND HRRR MODELS. && .FIRE WEATHER... ISSUED AT 345 AM MDT FRI SEP 25 2015 WARM AND DRY WEATHER WILL CONTINUE THROUGH THE WEEKEND. AREAS ALONG AND WEST OF THE LARAMIE RANGE WILL LIKELY SEE MINIMUM HUMIDITIES AT OR BELOW 15 PERCENT EACH AFTERNOON THROUGH SUN. ELEVATED CONDITIONS ARE LIKELY OVER THE WEEKEND AS WIND GUSTS COULD APPROACH 20-25 MPH AT TIMES. NO FIRE WEATHER HIGHLIGHTS ARE EXPECTED AT THIS TIME AS WINDS ARE EXPECTED TO REMAIN JUST BELOW CRITICAL THRESHOLDS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...CLH LONG TERM...ZAF AVIATION...MAJ FIRE WEATHER...CLH