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