Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/10/15
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
210 PM MST TUE SEP 8 2015
&&
.SYNOPSIS...
ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED AGAIN
TONIGHT...FAVORING SOUTHWEST ARIZONA AND SOUTHWEST CA. CLOUDS AND
HUMIDITY WILL INCREASE FROM WEDNESDAY INTO THURSDAY...RESULTING IN
AN INCREASE IN RAIN POTENTIAL DURING THIS PERIOD. TEMPERATURES WILL
BE LOWER AS WELL. HIGH PRESSURE AND DRIER AIR MOVING INTO THE
REGION WILL THEN REDUCE RAINFALL CHANCES AND ALLOW TEMPERATURES TO
RECOVER TO ABOVE-NORMAL VALUES FROM FRIDAY ONWARD INTO THE UPCOMING
WEEKEND. INCREASED RAINFALL CHANCES AND COOLER TEMPERATURES ARE THEN
POSSIBLE EARLY NEXT WEEK AS LOW PRESSURE MOVES INTO THE REGIONS FROM
THE WEST.
&&
.DISCUSSION...
.TONIGHT THROUGH THURSDAY... HURRICANE LINDA...WHICH IS CURRENTLY
FORECAST BY THE NHC TO CONTINUE TO MOVE NORTHWESTWARD WELL OFF THE
BAJA WEST COAST AND SLOWLY WEAKEN OVER THE NEXT FEW DAYS...IS
EXPECTED TO PLAY AN INCREASINGLY IMPORTANT RULE IN OUR WEATHER OVER
THE NEXT SEVERAL DAYS. CURRENT MODEL SUITES CONTINUE TO FORECAST A
DEEP MOISTURE SURGE WILL MOVE NORTHWARD UP THE GULF OF CALIFORNIA
TONIGHT AND WEDNESDAY...BETWEEN LINDA AND STRONG HIGH PRESSURE
RIDGING OVER NORTHWEST MAINLAND MEXICO...THEN INTO SE CA/SOUTHERN AZ
ON WEDNESDAY NIGHT AND THURSDAY. VERY HIGH PWATS...BETWEEN 2.00 AND
2.25 INCHES ARE EXPECTED TO SURGE NORTHWARD INTO THE REGION. AHEAD
OF THE MOISTURE SURGE...TONIGHT IS EXPECTED TO BE FAIRLY
QUIET...WITH THE LATEST HRRR HIGH-RES MODEL RUN SHOWING ISOLATED
THUNDERSTORM DEVELOPMENT OVER SE CA AND SW THIS AFTERNOON AND
EVENING. HIGH PRESSURE RIDGING IS EXPECTED TO KEEP SOUTH-CENTRAL
ARIZONA MAINLY THUNDERSTORM-FREE THIS AFTERNOON...WITH PERHAPS ONE
OR TWO STORMS DEVELOPING THIS EVENING IF OUTFLOWS FROM STORMS TO THE
WEST MANAGE TO MAKE THEIR WAY INTO THE REGION.
TOMORROW AND TOMORROW NIGHT SHOULD SEE AS INCREASE IN CONVECTIVE
ACTIVITY AS THE MAIN MOISTURE SURGE ARRIVES. HOWEVER...IT APPEARS
THAT THE CONVECTIVE ACTIVITY MAY BE MOSTLY WIDESPREAD SHOWER
ACTIVITY...WITH JUST SOME ISOLATED THUNDERSTORMS...SINCE THE MID AND
UPPER LEVELS OF THE ATMOSPHERE ARE EXPECTED TO REMAIN QUITE WARM
(500MB TEMPS IN THE -5-6C RANGE)...AND THERE WILL BE CONSIDERABLE
CLOUDINESS MOVING INTO THE REGION...WHICH WILL GREATLY INHIBIT
DAYTIME HEATING. THE LATEST GFS FORECAST SOUNDING FOR PHOENIX ALSO
IS SHOWING A CAPPING INVERSION BETWEEN 700 AND 850MB TOMORROW
AFTERNOON. IT APPEARS THE BEST CHANCE FOR MEASURABLE RAINFALL WILL
BE TOMORROW NIGHT...WHEN THE MOISTURE IS DEEPEST AND A WEAK
SHORTWAVE MOVES NORTHWARD INTO THE REGION. IF ANY THUNDERSTORMS DO
FORM...THE VERY MOIST ENVIRONMENT WILL ALLOW THEM TO BE VERY
EFFICIENT RAINFALL PRODUCERS...WITH LOCALIZED FLOODING POSSIBLE.
THURSDAY WILL LIKELY SEE A GRADUAL REDUCTION IN SHOWER/THUNDERSTORM
ACTIVITY AS THE SHORTWAVE WEAKENS...AVAILABLE MOISTURE LEVELS
DECREASE...AND HIGH PRESSURE ALOFT BEGINS TO SHIFT BACK OVER THE
REGION. HIGH TEMPERATURES TOMORROW AND THURSDAY WILL LIKELY BE KEPT
BELOW NORMAL BY ALL THE CLOUDS AND SHOWERS...WITH MANY LOWER DESERT
HIGHS REMAINING IN THE 90S...BUT WITH DEWPOINTS WELL UP IN THE 60S
AND 70S MAKING IT FEEL QUITE MUGGY.
.FRIDAY THROUGH SUNDAY... MAINLY DRY CONDITIONS AND SOMEWHAT WARMER
TEMPERATURES ARE EXPECTED OVER SOUTH-CENTRAL ARIZONA DURING THIS
TIME PERIOD...AS HIGH PRESSURE ALOFT...AND SOMEWHAT DRIER AIR MOVES
INTO THE REGION. SW AZ AND SE CA WILL LIKELY SEE ISOLATED CONVECTIVE
ACTIVITY EACH DAY...AS LIGHT SOUTHERLY FLOW AHEAD OF AN UPPER
LOW...WHICH IS EXPECTED TO ABSORB THE REMAINS OF LINDA...KEEPS
MOISTURE LEVELS ELEVATED OVER THAT REGION. TEMPERATURES WILL LIKELY
REBOUND INTO THE 105-108F RANGE AT MOST LOWER DESERT LOCATIONS BY
SATURDAY AND SUNDAY...WHICH IS A BIT ABOVE NORMAL FOR THIS TIME OF
YEAR.
.MONDAY AND TUESDAY... AN INCREASE IN RAINFALL CHANCES...AND
SOMEWHAT COOLER TEMPERATURES IS POSSIBLE DURING THIS PERIOD AS THE
1ST STRONG UPPER LOW OF THE FALL SEASON APPROACHES THE PAC NW
COAST..AND BEGINS TO KICK THE AFOMENTIONED SOUTHERN CA UPPER LOW
INLAND INTO THE DESERT SOUTHWEST. ALTHOUGH MOST OF THE GFS ENSEMBLE
MEMBERS DO SHOW THE UPPER LOW MOVING INLAND INTO OUR REGION...THERE
IS STILL QUITE A BIT OF SPREAD CONCERNING THE TIMING OF THIS EVENT.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
LIGHT SHOWERS AND THICKER CLOUD COVER HAS REMAINED SOUTH OF THE
PHOENIX AREA THUS FAR BUT SOME INCREASED MID CLOUDS ARE STARTING TO
CREEP INTO THE REGION AS OF 17Z. WILL MAINTAIN SOME DEGREE OF BKN
CIGS AT ALL SITES THROUGH THE AFTERNOON/EVENING HOURS BUT IT APPEARS
STORM CHANCES ARE MINIMAL AND TOO LOW TO MENTION OUTRIGHT IN ANY OF
THE TAFS. THINKING THAT THERE WILL BE A BIG PUSH OF MOISTURE AND
CLOUD COVER INTO THE REGION LATE TONIGHT. QUITE A FEW MODELS
INDICATING WIDESPREAD 5-6KFT CIGS ACROSS THE REGION AFTER 07Z AND I
LOWERED CEILINGS A BIT FROM THE INHERITED FORECAST. RAIN CHANCES
STILL LOOK LOW LATE TONIGHT...THUS THE PRIMARY IMPACTS WILL BE
CONFINED TO LOWER CIGS.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SKIES REMAIN MOSTLY CLEAR THIS MORNING AND THAT COULD ALLOW FOR STORM
DEVELOPMENT LATER THIS AFTERNOON. MOST LIKELY LOCATION TO SEE STORMS
WOULD BE BLH AND I RETAINED THE MENTION OF VCTS LATE THIS
AFTERNOON/EVENING. STORMS SHOULD DISSIPATE BEFORE THEY REACH IPL.
AFTER THIS EVENING...EXPECT WIDESPREAD BKN-OVC CIGS TO PREVAIL
THROUGH AT LEAST LATE MORNING WEDNESDAY AS INCREASED MOISTURE MOVES
INTO THE AREA.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
MOISTURE WILL GRADUALLY DIMINISH THROUGH THE WEEKEND INTO NEXT WEEK
BUT THERE WILL REMAIN AT LEAST A SLIGHT CHANCE OF MOUNTAIN SHOWERS
AND THUNDERSTORMS THROUGH NEXT WEEK. HUMIDITIES WILL FALL INTO THE
15-25 PERCENT RANGE EACH AFTERNOON WITH GOOD OVERNIGHT RECOVERIES
EXPECTED. WINDS WILL FAVOR THEIR TYPICAL DIURNAL UPSLOPE/DOWNVALLEY
PATTERNS.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT ACCORDING TO STANDARD PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA
AVIATION...LEINS
FIRE WEATHER...LEINS
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
1021 AM MST TUE SEP 8 2015
.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS...
&&
.SYNOPSIS...
ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED AGAIN
TODAY...FAVORING SOUTHWEST ARIZONA. CLOUDS AND HUMIDITY WILL INCREASE
TUESDAY NIGHT AND WEDNESDAY ALONG WITH A MODEST INCREASE IN RAIN
POTENTIAL LINGERING THROUGH THURSDAY. TEMPERATURES WILL BE LOWER AS
WELL. BY THE END OF THE WEEK TEMPERATURES WILL BE INCREASING AS DRIER
AIR MOVES INTO THE REGION. STORM CHANCES LIMITED TO THE HIGHER
TERRAIN FRIDAY THROUGH MONDAY.
&&
.DISCUSSION... A RATHER WARM...AND MUGGY MORNING (FOR EARLY SEPT)
ACROSS OUR CWA TODAY AS SOUTHWESTERLY FLOW ALOFT PULLS CONSIDERABLE
MID-LEVEL MOISTURE INLAND FROM THE TROPICAL EASTERN PACIFIC. THE
COMBINATION OF THIS MID-LEVEL MOISTURE ALONG WITH A WEAK SHORTWAVE
THAT IS MOVING WESTWARD ACROSS NORTHERN AZ IS TRIGGERING ISOLATED-
SCATTERED SHOWER/THUNDERSTORM ACTIVITY ACROSS SOUTHWEST MARICOPA
COUNTY...WITH ANOTHER AREA OF CONVECTION ACROSS SE PINAL
COUNTY...WHICH IS UNDERNEATH THE PLUME OF DEEPEST MOISTURE WHICH CAN
BE SEEN ON THE LATEST IR SATELLITE IMAGERY. GIVEN THESE LATEST
TRENDS...AND THE CURRENT HRRR HIGH-RES MODEL FORECAST...HAVE DECIDED
TO RAISE POPS A BIT ACROSS SOUTHERN MARICOPA AND NE PINAL COUNTIES
THROUGH THE REST OF THE MORNING HOURS. IT STILL LOOKS LIKE WE WILL
HAVE A BIT OF A BREAK IN THE SHOWER ACTIVITY EARLY THIS AFTERNOON
BEFORE MORE SHOWERS/TSTORMS DEVELOP...MAINLY OVER SW AZ/SE CA LATER
THIS AFTERNOON AND THIS EVENING. AS FAR AS TEMPERATURE/DEWPOINT TRENDS
ARE CONCERNED...OUR HOURLY GRIDS SEEM TO BE HOLDING UP WELL...AND NO
FURTHER UPDATES ARE PLANNED.
&&
.PREVIOUS DISCUSSION... TODAY THROUGH THURSDAY...STRONG
SOUTHWESTERLY FLOW ALOFT CONTINUES OVER THE FORECAST AREA AS WE ARE
SITUATED BETWEEN A HIGH CENTERED OVER FAR NORTHERN MEXICO AND A
TROUGH OFF THE BAJA COAST. THE OTHER SIGNIFICANT FLOW FEATURE OF
INTEREST IS HURRICANE LINDA WHICH WAS CENTERED ABOUT 300 MILES
SOUTHWEST OF THE SOUTHERN TIP OF BAJA EARLY THIS MORNING. CLOSER TO
HOME A BAND OF CLOUDS WAS COVERING MUCH OF THE SOUTHEAST HALF OF
ARIZONA WITH SOME EMBEDDED VERY LIGHT SHOWERS IN A NARROW CORRIDOR
OVER PORTIONS OF MARICOPA...PINAL...AND GILA COUNTIES. THE
CLOUDINESS IS LIKELY BEING AIDED BY THE RIGHT ENTRANCE REGION OF THE
JET INTERACTING WITH RESIDENT MOISTURE ALONG WITH A LITTLE BIT OF
HIGH LEVEL MOISTURE FROM LINDA. MODELS ARE IN GOOD AGREEMENT FOR
TODAY IN SHOWING A WESTWARD SHIFT OF THE HIGH AND A NORTHWARD
DISPLACEMENT OF THE JET. THEY ALSO DO NOT SHOW MUCH OF ANY INCREASE
IN LOWER LEVEL MOISTURE. THUS THEY GENERALLY SHOW A DOWNTREND IN
CAPE FOR TODAY COMPARED TO MONDAY. ONE EXCEPTION IS SOUTHEAST
CALIFORNIA WHERE CAPE EXPANDS FURTHER INTO THE LOWER DESERTS THERE.
THIS ADDS UP TO SLIGHT CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS
THE LOWER ELEVATIONS OF OUR FORECAST AREA...MARGINALLY BETTER OVER
THE HIGHER TERRAIN. TUESDAY NIGHT THROUGH THURSDAY THE FORECAST IS
QUITE CHALLENGING. IN GENERAL...THE MODELS SHOW A GULF SURGE LEADING
TO A SIGNIFICANT INCREASE IN LOWER LEVEL MOISTURE. THEY ALSO SHOW A
SIGNIFICANT INCREASE IN MID AND HIGH LEVEL CLOUDINESS...EMANATING
FROM LINDA. HOWEVER THERE ARE SOME NOTABLE DIFFERENCES IN THE TIMING
AND MAGNITUDE OF THE MOISTURE INCREASE AS WELL AS TIMING AND TRACK
OF ONE OR MORE PERTURBATIONS MOVING NORTHWARD ACROSS THE MEXICO
BORDER. THE NAM IS FASTER WITH THE MOISTURE INCREASE THAN THE GFS
AND ECMWF. IT IS ALSO FASTER WITH THE ARRIVAL OF A SHORT WAVE FROM
BAJA AND TRACKS IT FURTHER EAST FOR MORE IMPACT ON EASTERN PORTIONS
OF OUR AREA. DESPITE ALL OF THAT THE NAM MODEL RUN QPF IS
MODEST...BETTER OVER SOUTHEAST ARIZONA. IN FACT ALL OF THE MODELS
SHOW MODEST QPF INCLUDING THE GFS WHICH TENDS TO BE
OVERDONE...THOUGH IT HAS A COUPLE OF LOCALIZED HIGH TERRAIN
BULLSEYES. THE MAIN REASONS FOR THE UNDERWHELMING MODEL PRECIP
FORECAST IS LACK OF CAPE DUE TO POOR LAPSE RATES AS WELL AS LACK OF
DYNAMICAL FORCING. THUS OUR POPS REMAIN MODEST. THERE COULD BE
SHOWERS AT ANY TIME AND IF ANY OF THEM MANAGE TO HAVE SOME STRENGTH
THEY WILL BE ABLE TO PRODUCE A LOT OF PRECIP IN A VERY LOCALIZED
AREA. AS FOR TEMPERATURES...ANTICIPATE SLIGHTLY WARMER CONDITIONS
TODAY. COOLER CONDITIONS WEDNESDAY WITH MORE CLOUDINESS AND
HUMIDITY...MOST NOTICEABLY OVER SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...AND SLIGHTLY WARMER THURSDAY AS CLOUDS START TO TREND
DOWN. MEANWHILE...LINDA WILL REMAIN OFFSHORE AND WEAKEN AS IT MOVES
NORTHWESTWARD.
FRIDAY THROUGH MONDAY...
THE FLOW BECOMES MORE AMPLIFIED LATE IN THE WEEK. WITH A RIDGE AXIS
OVER THE INTERIOR WEST. WITH A NORTHERLY COMPONENT TO THE FLOW...A
DRYING TREND IS EXPECTED. ECMWF IS SLOWER WITH THE DRYING THAN THE
GFS BUT IT TENDS TO BE OVERLY GENEROUS WITH MOISTURE. ONLY SLIGHT
CHANCE POPS ARE LEFT OVER THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA
FRIDAY AND SATURDAY. EARLY NEXT WEEK...WEST COAST TROUGHING
REDEVELOPS AND THE RIDGE SHIFTS EASTWARD A BIT SUCH LEADING TO A
SOUTHERLY COMPONENT TO THE FLOW. INTRODUCED SOME SLIGHT CHANCE POPS
SUNDAY AND MONDAY OVER FAVORED HIGHER TERRAIN AREAS AS EVEN THE GFS
SHOWS MORE MOISTURE AVAILABLE.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
LIGHT SHOWERS AND THICKER CLOUD COVER HAS REMAINED SOUTH OF THE
PHOENIX AREA THUS FAR BUT SOME INCREASED MID CLOUDS ARE STARTING TO
CREEP INTO THE REGION AS OF 17Z. WILL MAINTAIN SOME DEGREE OF BKN
CIGS AT ALL SITES THROUGH THE AFTERNOON/EVENING HOURS BUT IT APPEARS
STORM CHANCES ARE MINIMAL AND TOO LOW TO MENTION OUTRIGHT IN ANY OF
THE TAFS. THINKING THAT THERE WILL BE A BIG PUSH OF MOISTURE AND
CLOUD COVER INTO THE REGION LATE TONIGHT. QUITE A FEW MODELS
INDICATING WIDESPREAD 5-6KFT CIGS ACROSS THE REGION AFTER 07Z AND I
LOWERED CEILINGS A BIT FROM THE INHERITED FORECAST. RAIN CHANCES
STILL LOOK LOW LATE TONIGHT...THUS THE PRIMARY IMPACTS WILL BE
CONFINED TO LOWER CIGS.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SKIES REMAIN MOSTLY CLEAR THIS MORNING AND THAT COULD ALLOW FOR STORM
DEVELOPMENT LATER THIS AFTERNOON. MOST LIKELY LOCATION TO SEE STORMS
WOULD BE BLH AND I RETAINED THE MENTION OF VCTS LATE THIS
AFTERNOON/EVENING. STORMS SHOULD DISSIPATE BEFORE THEY REACH IPL.
AFTER THIS EVENING...EXPECT WIDESPREAD BKN-OVC CIGS TO PREVAIL
THROUGH AT LEAST LATE MORNING WEDNESDAY AS INCREASED MOISTURE MOVES
INTO THE AREA.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
MOISTURE WILL GRADUALLY DIMINISH THROUGH THE WEEKEND INTO NEXT WEEK
BUT THERE WILL REMAIN AT LEAST A SLIGHT CHANCE OF MOUNTAIN SHOWERS
AND THUNDERSTORMS THROUGH NEXT WEEK. HUMIDITIES WILL FALL INTO THE
15-25 PERCENT RANGE EACH AFTERNOON WITH GOOD OVERNIGHT RECOVERIES
EXPECTED. WINDS WILL FAVOR THEIR TYPICAL DIURNAL UPSLOPE/DOWNVALLEY
PATTERNS.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT ACCORDING TO STANDARD PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/AJ
AVIATION...LEINS
FIRE WEATHER...LEINS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
850 AM MST TUE SEP 8 2015
.SYNOPSIS...
ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED AGAIN
TODAY...FAVORING SOUTHWEST ARIZONA. CLOUDS AND HUMIDITY WILL INCREASE
TUESDAY NIGHT AND WEDNESDAY ALONG WITH A MODEST INCREASE IN RAIN
POTENTIAL LINGERING THROUGH THURSDAY. TEMPERATURES WILL BE LOWER AS
WELL. BY THE END OF THE WEEK TEMPERATURES WILL BE INCREASING AS DRIER
AIR MOVES INTO THE REGION. STORM CHANCES LIMITED TO THE HIGHER
TERRAIN FRIDAY THROUGH MONDAY.
&&
.DISCUSSION... A RATHER WARM...AND MUGGY MORNING (FOR EARLY SEPT)
ACROSS OUR CWA TODAY AS SOUTHWESTERLY FLOW ALOFT PULLS CONSIDERABLE
MID-LEVEL MOISTURE INLAND FROM THE TROPICAL EASTERN PACIFIC. THE
COMBINATION OF THIS MID-LEVEL MOISTURE ALONG WITH A WEAK SHORTWAVE
THAT IS MOVING WESTWARD ACROSS NORTHERN AZ IS TRIGGERING ISOLATED-
SCATTERED SHOWER/THUNDERSTORM ACTIVITY ACROSS SOUTHWEST MARICOPA
COUNTY...WITH ANOTHER AREA OF CONVECTION ACROSS SE PINAL
COUNTY...WHICH IS UNDERNEATH THE PLUME OF DEEPEST MOISTURE WHICH CAN
BE SEEN ON THE LATEST IR SATELLITE IMAGERY. GIVEN THESE LATEST
TRENDS...AND THE CURRENT HRRR HIGH-RES MODEL FORECAST...HAVE DECIDED
TO RAISE POPS A BIT ACROSS SOUTHERN MARICOPA AND NE PINAL COUNTIES
THROUGH THE REST OF THE MORNING HOURS. IT STILL LOOKS LIKE WE WILL
HAVE A BIT OF A BREAK IN THE SHOWER ACTIVITY EARLY THIS AFTERNOON
BEFORE MORE SHOWERS/TSTORMS DEVELOP...MAINLY OVER SW AZ/SE CA LATER
THIS AFTERNOON AND THIS EVENING. AS FAR AS TEMPERATURE/DEWPOINT TRENDS
ARE CONCERNED...OUR HOURLY GRIDS SEEM TO BE HOLDING UP WELL...AND NO
FURTHER UPDATES ARE PLANNED.
&&
.PREVIOUS DISCUSSION... TODAY THROUGH THURSDAY...STRONG
SOUTHWESTERLY FLOW ALOFT CONTINUES OVER THE FORECAST AREA AS WE ARE
SITUATED BETWEEN A HIGH CENTERED OVER FAR NORTHERN MEXICO AND A
TROUGH OFF THE BAJA COAST. THE OTHER SIGNIFICANT FLOW FEATURE OF
INTEREST IS HURRICANE LINDA WHICH WAS CENTERED ABOUT 300 MILES
SOUTHWEST OF THE SOUTHERN TIP OF BAJA EARLY THIS MORNING. CLOSER TO
HOME A BAND OF CLOUDS WAS COVERING MUCH OF THE SOUTHEAST HALF OF
ARIZONA WITH SOME EMBEDDED VERY LIGHT SHOWERS IN A NARROW CORRIDOR
OVER PORTIONS OF MARICOPA...PINAL...AND GILA COUNTIES. THE
CLOUDINESS IS LIKELY BEING AIDED BY THE RIGHT ENTRANCE REGION OF THE
JET INTERACTING WITH RESIDENT MOISTURE ALONG WITH A LITTLE BIT OF
HIGH LEVEL MOISTURE FROM LINDA. MODELS ARE IN GOOD AGREEMENT FOR
TODAY IN SHOWING A WESTWARD SHIFT OF THE HIGH AND A NORTHWARD
DISPLACEMENT OF THE JET. THEY ALSO DO NOT SHOW MUCH OF ANY INCREASE
IN LOWER LEVEL MOISTURE. THUS THEY GENERALLY SHOW A DOWNTREND IN
CAPE FOR TODAY COMPARED TO MONDAY. ONE EXCEPTION IS SOUTHEAST
CALIFORNIA WHERE CAPE EXPANDS FURTHER INTO THE LOWER DESERTS THERE.
THIS ADDS UP TO SLIGHT CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS
THE LOWER ELEVATIONS OF OUR FORECAST AREA...MARGINALLY BETTER OVER
THE HIGHER TERRAIN. TUESDAY NIGHT THROUGH THURSDAY THE FORECAST IS
QUITE CHALLENGING. IN GENERAL...THE MODELS SHOW A GULF SURGE LEADING
TO A SIGNIFICANT INCREASE IN LOWER LEVEL MOISTURE. THEY ALSO SHOW A
SIGNIFICANT INCREASE IN MID AND HIGH LEVEL CLOUDINESS...EMANATING
FROM LINDA. HOWEVER THERE ARE SOME NOTABLE DIFFERENCES IN THE TIMING
AND MAGNITUDE OF THE MOISTURE INCREASE AS WELL AS TIMING AND TRACK
OF ONE OR MORE PERTURBATIONS MOVING NORTHWARD ACROSS THE MEXICO
BORDER. THE NAM IS FASTER WITH THE MOISTURE INCREASE THAN THE GFS
AND ECMWF. IT IS ALSO FASTER WITH THE ARRIVAL OF A SHORT WAVE FROM
BAJA AND TRACKS IT FURTHER EAST FOR MORE IMPACT ON EASTERN PORTIONS
OF OUR AREA. DESPITE ALL OF THAT THE NAM MODEL RUN QPF IS
MODEST...BETTER OVER SOUTHEAST ARIZONA. IN FACT ALL OF THE MODELS
SHOW MODEST QPF INCLUDING THE GFS WHICH TENDS TO BE
OVERDONE...THOUGH IT HAS A COUPLE OF LOCALIZED HIGH TERRAIN
BULLSEYES. THE MAIN REASONS FOR THE UNDERWHELMING MODEL PRECIP
FORECAST IS LACK OF CAPE DUE TO POOR LAPSE RATES AS WELL AS LACK OF
DYNAMICAL FORCING. THUS OUR POPS REMAIN MODEST. THERE COULD BE
SHOWERS AT ANY TIME AND IF ANY OF THEM MANAGE TO HAVE SOME STRENGTH
THEY WILL BE ABLE TO PRODUCE A LOT OF PRECIP IN A VERY LOCALIZED
AREA. AS FOR TEMPERATURES...ANTICIPATE SLIGHTLY WARMER CONDITIONS
TODAY. COOLER CONDITIONS WEDNESDAY WITH MORE CLOUDINESS AND
HUMIDITY...MOST NOTICEABLY OVER SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...AND SLIGHTLY WARMER THURSDAY AS CLOUDS START TO TREND
DOWN. MEANWHILE...LINDA WILL REMAIN OFFSHORE AND WEAKEN AS IT MOVES
NORTHWESTWARD.
FRIDAY THROUGH MONDAY...
THE FLOW BECOMES MORE AMPLIFIED LATE IN THE WEEK. WITH A RIDGE AXIS
OVER THE INTERIOR WEST. WITH A NORTHERLY COMPONENT TO THE FLOW...A
DRYING TREND IS EXPECTED. ECMWF IS SLOWER WITH THE DRYING THAN THE
GFS BUT IT TENDS TO BE OVERLY GENEROUS WITH MOISTURE. ONLY SLIGHT
CHANCE POPS ARE LEFT OVER THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA
FRIDAY AND SATURDAY. EARLY NEXT WEEK...WEST COAST TROUGHING
REDEVELOPS AND THE RIDGE SHIFTS EASTWARD A BIT SUCH LEADING TO A
SOUTHERLY COMPONENT TO THE FLOW. INTRODUCED SOME SLIGHT CHANCE POPS
SUNDAY AND MONDAY OVER FAVORED HIGHER TERRAIN AREAS AS EVEN THE GFS
SHOWS MORE MOISTURE AVAILABLE.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
BKN-OVC MID/HIGH LEVEL CIGS WILL PREVAIL OVER TERMINAL SITES MUCH OF
THE DAY...WITH VIRGA COMMON THIS MORNING. A STRAY SHOWER/SPRINKLE
MAY BE POSSIBLE THIS MORNING...THOUGH IMPACTS WOULD BE LITTLE TO
NONE. CHANCES FOR ANY STORMS DIRECTLY IMPACTING AN AIRFIELD THIS
AFTERNOON OR EVENING ARE TOO REMOTE TO INCLUDE...AND CONFIDENCE IS
MODERATE THAT TSRA WILL REMAIN WELL REMOVED FROM AERODROMES THROUGH
THE 03Z-04Z EVENING PUSH.
SFC WINDS MAY STAY LIGHT AND VARIABLE THIS MORNING...THOUGH SHOULD
EVENTUALLY FAVOR AN EASTERLY COMPONENT BEFORE SWITCHING TO WESTERLY
EARLY AFTERNOON. CONFIDENCE DECLINES SUBSTANTIALLY LATE THIS EVENING
AND OVERNIGHT...AS A SURGE OF VERY MOIST AIR LIKELY MOVES INTO CNTRL
ARIZONA. VERY LOW CONFIDENCE PRECLUDES A MORE DEFINITE MENTION IN
THIS TAF PACKAGE...HOWEVER SHRA AND CIGS AOB 6K FT COULD BE POSSIBLE
AROUND OR JUST PRIOR TO 12Z WEDNESDAY.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
MOSTLY CLEAR SKIES IN THE MORNING WILL GIVE WAY TO SCT-BKN
CONDITIONS IN THE AFTERNOON. TSRA MAY MORE DIRECTLY IMPACT SERN
CALIFORNIA TERMINALS TUESDAY AFTERNOON VERSUS PREVIOUS DAYS WITH
SOMEWHAT BETTER CONFIDENCE AT KBLH. AFTERNOON STORMS OVER THE
BAJA SPINE AGAIN COULD SURVIVE INTO THE LOWER DESERTS OF IMPERIAL
COUNTY...BUT CONFIDENCE ON ACTIVITY REACHING KIPL IS NOT HIGH ENOUGH
TO EVEN INCLUDE A VICINITY MENTION.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
SLIGHT SHOWER AND THUNDERSTORM CHANCES THURSDAY WILL TAPER OFF TO
NEARLY NEGLIGIBLE CHANCES BY THE WEEKEND. INCREASED HUMIDITY
LEVELS THURSDAY...WITH MINIMUM AFTERNOON READINGS ONLY RANGING
BETWEEN 20 AND 35 PERCENT WILL LOWER INTO A 10 TO 25 PERCENT RANGE
OVER THE WEEKEND. OVERNIGHT RECOVERY WILL BE GOOD TO EXCELLENT. WITH
THE DRYING TREND...HIGH TEMPERATURES WILL CLIMB INTO THE WEEKEND
REACHING A 105 TO 110 DEGREE RANGE AT LOWER ELEVATIONS. WINDS WILL
FAVOR A WEST TO SOUTHWEST DIRECTION IN THE AFTERNOON...WITH THE
TYPICAL LIGHT DRAINAGE COMPONENT OVERNIGHT.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT ACCORDING TO STANDARD PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/AJ
AVIATION...NOLTE
FIRE WEATHER...BRECKENRIDGE
AREA FORECAST DISCUSSION
NWS TUCSON AZ
240 AM MST TUE SEP 8 2015
.SYNOPSIS...SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS TODAY THROUGH WEDNESDAY. A DRYING TREND WILL LIKELY
BEGIN THURSDAY...WITH SHOWERS AND THUNDERSTORMS CONFINED TO MAINLY
NEAR THE EASTERN MOUNTAINS THIS WEEKEND. NEAR NORMAL HIGH
TEMPERATURES WILL OCCUR EXCEPT FOR SOME COOLING WEDNESDAY AND
THURSDAY.
&&
.DISCUSSION...SW FLOW ALOFT OVER THE AREA THIS AM WITH SCATTERED
MAINLY MID TO HIGH LEVEL CLOUDS. RADAR HAS BEEN DETECTING SOME LIGHT
SHOWERS/SPRINKLES W AND NW OF TUCSON...WHICH MOST LIKELY IS NOT
MAKING IT TO THE GROUND. LATEST HRRR RUNS KEEP ISOLATED LIGHT
SHOWERS/SPRINKLES ACROSS ERN PINAL/NRN GRAHAM THIS MORNING.
LAST NIGHTS UPPER AIR PLOTS PLACED THE UPPER HIGH OVER TEXAS BIG
BEND WITH AXIS EXTENDING WEST ACROSS NRN SONORA/BAJA. WATER VAPOR
SHOWED A WEAK UPPER LEVEL TROF OVER NW AZ WHICH IS PROGGED TO MOVE E
TODAY. PRECIPITABLE WATER REMAINS RATHER HIGH ACROSS THE AREA FOR
EARLY SEPTEMBER WITH VALUES MOSTLY IN THE 1.25"-1.70" RANGE HIGHEST
OUT WEST. PW VALUES THROUGHOUT THE GULF OF CA RANGED FROM 2" IN THE
NORTH TO 2.50" AT THE MOUTH AS SELY WINDS ARE STARTING TO INCREASE
THANKS TO HRCN LINDA. SO THE GLFCA IS ALREADY FLOODED WITH MOISTURE.
FOR TODAY...AS THE UPPER HIGH OVER THE TEXAS BIG BEND MOVES INTO NRN
CHIHUAHUA...THE ORIENTATION OF THE ASSOCIATED RIDGE AXIS LIFTING NE
INTO SRN CA FROM NRN BAJA. THE NAM IS SUGGESTING THAT A PIECE OF
ENERGY ON THE NE FLANK OF HRCN LINDA MAY PUSH N ACROSS SONORA MX
TODAY PROVIDING THE UPPER LEVEL SUPPORT FOR POSSIBLE MCS JUST S OF
THE INTNL BORDER. GFS/EC ALONG WITH UOFA WRF RUNS OF NAM/GFS NOT HOT
ON THIS IDEA. SO FOR NOW WILL GO WITH A LOW GRADE MONSOON FORECAST
WITH EMPHASIS ON THE BORDER LOCALS...ESPECIALLY SANTA CRUZ COUNTY.
HOWEVER CONFIDENCE IS LOW ESPECIALLY LATER THIS AFTERNOON INTO THIS
EVENING.
WEDNESDAY...HIGHER PW VALUES FROM THE GULF OF CALIFORNIA IS PUSHED
INTO THE LOWER DESERTS WITH 2+" VALUES OVER WRN PIMA COUNTY. THE BIG
QUESTION FOR WEDNESDAY WILL BE AMOUNT OF SUN THE AREA WILL GET.
RIGHT NOW LOOKS LIKE A LOT OF CLOUDS BEING AROUND WITH SCATTERED
SHOWERS AND ISOLATED EMBEDDED BOOMERS WITH THE BEST CHANCES FOR
STORMS BEING WEST AND SOUTH OF TUCSON.
MAIN THREAT FOR STORMS LATER TODAY AND WEDNESDAY WILL BE LOCALIZED
HEAVY RAINERS ALONG WITH FLASH FLOODING CONCERNS.
THURSDAY...BATTLE GROUND DAY AS NORTHERLY FLOW STARTS TO PUSH INTO
THE NRN AREAS WHILE IT REMAINS VERY MOIST ACROSS SOUTHERN SECTIONS.
AT THIS TIME WILL RIDE THE INHERITED SLIGHT CHANCE TO LOW END CHANCE
TYPE POPS.
FRIDAY INTO SUNDAY...DRIER NORTHERLY FLOW OVER THE AREAS WILL BRING
ABOUT A MARKED DECREASE IN THUNDERSTORM ACTIVITY...MAINLY ACROSS THE
ERN MOUNTAINS.
EARLY NEXT WEEK...MAY SEE A SLIGHT UPTICK IN STORM COVERAGE AS FLOW
ALOFT BECOME A BIT MORE SOUTHERLY.
HIGH TEMPERATURES FOR THE MAJORITY OF THIS FORECAST PACKAGE WILL BE
NEAR NORMAL...WITH THE EXCEPTION BEING WEDNESDAY AND THURSDAY.
&&
.AVIATION...VALID THRU 09/12Z.
FEW-SCT CLOUDS AT 12-16K FT AGL AND SCT-BKN CLOUDS AOA 20K FT AGL
THRU 08/21Z. AFT 08/21Z...SCT-BKN CLOUDS AT 8-12K FT AGL AND BKN-OVC
CLOUDS AOA 15K FT AGL. SLIGHT CHANCE -SHRA/-TSRA THRU 08/21Z...THEN
SCT SHRA/TSRA. BRIEF MVFR CONDITIONS AND WIND GUSTS OF 30-40 KTS
WILL OCCUR WITH THE STRONGER TSRA. OTHERWISE...SURFACE WIND LESS
THAN 10 KTS THRU THE FORECAST PERIOD. PARTIAL CLEARING LATE TONIGHT
AND DURING THE OVERNIGHT HOURS. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.
&&
.FIRE WEATHER...THERE WILL BE A CHANCE OF MAINLY AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS THROUGH THURSDAY. BY LATE THIS
WEEK AND OVER THE UPCOMING WEEKEND...MUCH LESS SHOWER/THUNDERSTORM
ACTIVITY IS EXPECTED...WITH ANY CONVECTION CONFINED TO THE HIGHER
TERRAIN ALONG THE NEW MEXICO BORDER. STRONG...GUSTY AND ERRATIC
WINDS WILL OCCUR WITH THE STRONGER THUNDERSTORMS. OTHERWISE... 20-
FOOT WINDS WILL BE MAINLY TERRAIN DRIVEN AND LESS THAN 15 MPH.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
955 AM PDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE ALOFT WILL BRING HOT DAYTIME WEATHER THROUGH THURSDAY...
FOLLOWED BY SLOW COOLING SPREADING INLAND FROM THE COAST THROUGH
EARLY NEXT WEEK ALONG WITH SLOW DRYING. TROPICAL MOISTURE WILL
BRING A CHANCE OF AFTERNOON AND EARLY EVENING THUNDERSTORMS TO THE
MOUNTAINS...DESERTS...AND PORTIONS OF THE INLAND EMPIRE INTO FRIDAY
WITH CHANCES GREATEST TODAY THROUGH THURSDAY. AN INCREASED FLASH
FLOOD THREAT WILL ACCOMPANY THESE THUNDERSTORMS.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
A MOIST AND UNSTABLE ATMOSPHERE REMAINS IN PLACE THIS MORNING...WITH
THE 12Z MIRAMAR SOUNDING SHOWING 1.77 INCHES OF PRECIPITABLE WATER
AND 1058 J/KG OF MOST UNSTABLE CAPE...WITH SOUTH TO SOUTHEAST FLOW
IN THE LOW LEVELS AND SOUTHWEST FLOW ALOFT. WITH THIS ATMOSPHERIC
SET-UP...AND THE AMPLE SUNSHINE THAT THE REGION WILL EXPERIENCE THIS
MORNING...THUNDERSTORMS SHOULD ERUPT OVER THE MOUNTAINS AND DESERTS
THIS AFTERNOON INTO EARLY EVENING. THE 15Z HRRR SHOWS THE FIRST
THUNDERSTORMS POPPING OFF OVER THE MOUNTAINS BY 1 PM.
WATER VAPOR SATELLITE SHOWS HURRICANE LINDA SOUTHWEST OF SOUTHERN
BAJA...WITH SOME WISPS OF CLOUDS ASSOCIATED WITH LINDA MOVING OVER
SAN DIEGO COUNTY THIS MORNING. A RIDGE ALOFT IS CURRENTLY BUILDING
OVER THE REGION...AND WILL CONTINUE TO BUILD THROUGH AT LEAST
THURSDAY. THE RIDGE...IN ADDITION TO SOME INCREASING MOISTURE AT THE
SURFACE...WILL MAKE FOR HOT AND MUGGY DAYS FOR MOST AREAS. SURFACE
DEW POINTS ARE ALREADY IN THE MID 60S IN WESTERN SAN DIEGO COUNTY
AND ORANGE COUNTY. MORNING TEMPERATURES ARE ALREADY SEVERAL DEGREES
HIGHER THAN 24 HOURS AGO. WITH THE MORNING UPDATE...HIGH
TEMPERATURES FOR THE SAN DIEGO COUNTY VALLEYS AND COAST WERE
INCREASED BY 5 DEGREES TO BE MORE IN-LINE WITH WHAT THE ECMWF...NAM
AND GFS MOS WERE INDICATING. THUS...THE HEAT ADVISORY FOR THOSE
AREAS WAS CHANGED TO START TODAY. THE HEAT ADVISORIES FOR THE INLAND
EMPIRE...SANTA ANA MOUNTAINS/FOOTHILLS AND INLAND ORANGE COUNTY
REMAIN THE SAME.
OVER THE NEXT FEW DAYS...LINDA WILL WEAKEN AND MOVE NORTHWEST...WITH
LOW-TO-MID LEVEL WINDS BECOMING MORE EAST TO SOUTHEAST...AND
CONTINUALLY HIGHER MOISTURE ADVECTING INTO THE REGION. THE EASTERLY
FLOW COULD RESULT IN GREATER CHANCES FOR THE VALLEYS TO GET
THUNDERSTORMS...PARTICULARLY THURSDAY WHEN THE WRF INDICATES 700-500
MB WIND OF 15-20 KT OUT OF THE EAST. THE INLAND EMPIRE MAY HAVE A
DIFFICULT TIME GETTING THUNDERSTORMS TODAY...AS THE WRF DOES NOT
SHOW MUCH OF A CONVERGENCE BOUNDARY SETTING UP NEAR ELSINORE.
HOWEVER...THE WRF DOES SHOW A BETTER CONVERGENCE BOUNDARY SETTING UP
IN THAT AREA ON WEDNESDAY...SO THAT WOULD INDICATE A BETTER CHANCE
FOR THUNDERSTORMS FOR THE INLAND EMPIRE FOR THAT DAY.
BY TOMORROW...MODELS INDICATE PRECIPITABLE WATER INCREASING TO 1.9
INCHES...AND POSSIBLY NEAR 2 INCHES ON THURSDAY. THE THUNDERSTORMS
WILL BRING AN INCREASED FLASH FLOOD THREAT. SEE THE HYDROLOGY
SECTION BELOW FOR MORE DETAILS ON THE FLOODING POTENTIAL. BY
FRIDAY...THE GFS KEEPS THE REMNANT CIRCULATION FROM LINDA CLOSER TO
THE COAST THAN THE OTHER MODELS...AND SO PRECIPITABLE WATER DOES NOT
DECREASE MUCH...WHILE THE NAM12 AND SREF HAVE THE LINDA CIRCULATION
FARTHER TO THE SOUTHWEST...WITH PRECIPITABLE WATER DECREASING TO 1.5-
1.7 INCHES. THE GFS CONTINUES TO KEEP A FAIR AMOUNT OF MOISTURE IN
THE AREA SATURDAY...AND POSSIBLY ENOUGH SUNDAY AS WELL FOR SOME
THUNDERSTORMS OF THE MOUNTAINS AND POSSIBLY DESERTS. MAY NEED TO ADD
THUNDERSTORMS TO THE FORECAST FOR SATURDAY AND SUNDAY.
MEANWHILE...NIGHT AND MORNING MARINE LAYER STRATUS SHOULD REMAIN
ABSENT FOR A WHILE...DUE TO THE RIDGE AND INTERFERENCE FROM ALL OF
THE MID AND UPPER LEVEL MOISTURE.
GRADUAL COOLING LOOKS TO TAKE PLACE FRIDAY THROUGH EARLY NEXT WEEK
AS THE RIDGE ALOFT SLOWLY WEAKENS AND A TROUGH EVENTUALLY MOVES IN
ALONG THE WEST COAST EARLY NEXT WEEK.
&&
.HYDROLOGY...
FLASH FLOOD WATCH GOES INTO EFFECT AT NOON TODAY AND CONTINUES
THROUGH THURSDAY FOR THE MOUNTAINS...DESERTS AND PORTIONS OF THE
INLAND EMPIRE...AS THE ATMOSPHERE WILL REMAIN MOIST AND UNSTABLE
THROUGH THAT TIME. THIS WILL CREATE THE CHANCES FOR THUNDERSTORMS
PRODUCING HEAVY RAIN. THE WINDS ALOFT WILL BE LIGHT AS
WELL...RESULTING IN SLOW MOVING STORMS WHICH WILL INCREASE THE
THREAT OF FLASH FLOODING FURTHER. RAIN RATES OF 1 TO 2 INCHES PER
HOUR WILL BE POSSIBLE UNDERNEATH THE HEAVIER STORMS. THE FLASH FLOOD
THREAT STARTS TO DIMINISH FRIDAY INTO THE WEEKEND AS MOISTURE SLOWLY
DECREASES.
&&
.AVIATION...
081530Z...COASTAL...NO VIS RESTRICTIONS WILL OCCUR THROUGH WED
MORNING WITH OCCASIONAL CLOUDS ONLY ABOVE 10000 FEET MSL.
VALLEYS/MOUNTAINS/DESERTS...THUNDERSTORMS WILL DEVELOP THIS
AFTERNOON WITH TIMING 20Z TO 02Z...MOST NUMEROUS OVER THE
MOUNTAINS...BUT ISOLATED THUNDERSTORMS COULD OCCUR IN THE DESERTS
AND VALLEY FOOTHILLS. BASES WILL BE 9000 FT MSL WITH TOPS TO 45000
FT MSL POSSIBLE...WITH STRONG UP/DOWNDRAFTS AND LOCAL SURFACE GUSTS
OVER 40 KT. THERE IS A CHANCE KPSP AND KTRM COULD HAVE VCNTY
THUNDERSTORMS. THUNDERSTORMS COULD DEVELOP IN THE SAME AREAS WED
AFTERNOON. OUTSIDE OF THUNDERSTORMS...NO VIS RESTRICTIONS WILL
OCCUR...AND MOST CLOUDS WILL BE ABOVE 8000 FEET MSL.
&&
.MARINE...
830 AM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH SATURDAY.
&&
.BEACHES...
830 AM...THE LONG-PERIOD SOUTHWEST SWELL WILL GRADUALLY LOWER TODAY
BUT CONTINUE TO PRODUCE ELEVATED SURF AND STRONG RIP AND LONGSHORE
CURRENTS...MAINLY IN ORANGE COUNTY TODAY. THE BEACH HAZARDS
STATEMENT IS IN EFFECT FOR ORANGE COUNTY BEACHES THROUGH 8 PM THIS
EVENING...SEE LAXCFWSGX FOR DETAILS. FOR MORE SURF DETAILS SEE
LAXSRFSGX. A NEW SOUTH SOUTHEAST SWELL COMING FROM HURRICANE LINDA
WILL ARRIVE THURSDAY AND WILL BRING SOME 5-7 FOOT SURF...LOCALLY
HIGHER...IN NORTHERN ORANGE COUNTY THU/FRI.
&&
.SKYWARN...
SKYWARN ACTIVATION IS REQUESTED FOR THE MOUNTAINS...DESERTS...AND
PORTIONS OF THE INLAND EMPIRE FOR TODAY FROM NOON THROUGH 7 PM
THIS EVENING. ACTIVATION MAY BE NEEDED FOR SIMILAR AREAS AND TIMES
FOR WEDNESDAY AND THURSDAY AS WELL.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH FROM NOON PDT TODAY THROUGH THURSDAY EVENING
FOR COACHELLA VALLEY-RIVERSIDE COUNTY MOUNTAINS-SAN
BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO AND RIVERSIDE
COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY DESERTS-
SAN DIEGO COUNTY MOUNTAINS-SAN GORGONIO PASS NEAR BANNING AND
APPLE AND LUCERNE VALLEYS.
HEAT ADVISORY FROM NOON TODAY TO 6 PM PDT WEDNESDAY FOR SAN DIEGO
COUNTY COASTAL AREAS-SAN DIEGO COUNTY VALLEYS.
HEAT ADVISORY FROM NOON TODAY TO 6 PM PDT THURSDAY FOR ORANGE
COUNTY INLAND AREAS-SAN BERNARDINO AND RIVERSIDE COUNTY
VALLEYS-THE INLAND EMPIRE-SANTA ANA MOUNTAINS AND FOOTHILLS.
BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR ORANGE COUNTY
COASTAL AREAS.
PZ...NONE.
&&
$$
PUBLIC/HYDROLOGY...HARRISON
AVIATION/MARINE/BEACHES...MAXWELL
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
533 PM MDT WED SEP 9 2015
.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 215 PM MDT WED SEP 9 2015
DRY WEST NORTHWEST FLOW PREVAILS AND KEEPS MOISTURE SOUTH OF OUR
SOUTHERN BORDER. THERE IS REMOTE CHANCE THAT A BRIEF SHOWER/STORM
FORMS OVER THE ERN SAN JUAN MOUNTAINS. WATER VAPOR SHOWS
PRONOUNCED DRY LAYER ACROSS THE SOUTH...AND COULD BE ONE REASON
WHY THE HRRR MODEL SHOWS NO SHOWERS/STORMS ACROSS THE SRN
MOUNTAINS AND FOOTHILLS.
STABLE CONDITIONS CONTINUE THURSDAY KEEPING CONDITIONS DRY AND
WINDS UPSLOPE/DOWNSLOPE INDUCED. VERTICAL PROFILES INDICATE WINDS
BELOW 600 MB WILL BE VERY LIGHT - LESS THAN 15 KTS AND NEAR NON-
EXISTENT AT THE SURFACE ON THURSDAY...WITH THE EXCEPTION OF THE
SOUTHWEST COLORADO VALLEYS WHERE WINDS ALOFT AT 300 MB ARE STILL
40 KTS THROUGH THURSDAY EVENING SO SOME HIGHER GUSTS (TO 20 MPH
OR SO) MAY MIX DOWN TO THE SURFACE. TEMPERATURES WILL REMAIN
ABOVE NORMAL.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 215 PM MDT WED SEP 9 2015
VERY LITTLE CHANGE IN THE MID RANGE FORECAST PERIOD AS HIGH
PRESSURE PERSISTS. ALONG THE WEST COAST...A TROUGH DEVELOPS ON
SATURDAY AND WHAT HAPPENS WITH THIS SYSTEM IS OUR NEXT FORECAST
CHALLENGE. THE 12Z GFS INDICATES A SMALL CLOSED LOW DEVELOPING IN
SOUTHERN UTAH AND PROPAGATING INTO WESTERN COLORADO ON MONDAY
WHILE THE EC BRINGS AN OPEN WAVE TROUGH INTO THE FOUR CORNERS.
BOTH SOLUTIONS BRING PRECIPITATION TO THE REGION...SO CONFIDENCE
IS GOOD ON AN INCREASE IN MOISTURE AND THE POSSIBILITY OF RAIN
EARLY NEXT WEEK. TUESDAY LOOKS QUITE BREEZY AND WET WITH EITHER
MODEL SOLUTION AS A COLD 700 MB LOW PRESSURE SYSTEM BARRELS DOWN
INTO THE NORTHERN ROCKIES ON TUESDAY INTERACTING WITH THE MUCH
WARMER AIR IN PLACE TO THE SOUTH. THERE HAVE BEEN PRETTY MAJOR
FLUCTUATIONS RUN TO RUN IN THE FORECAST MODELS FOR EARLY NEXT
WEEK AS THE PATTERN TRANSITIONS...SO DETAILS WILL HAVE TO BE
IRONED OUT AS A SOLUTION BECOMES MORE CONSISTENT. THE GENERAL
PATTERN DOES LOOK WETTER AND COOLER NEXT WEEK WITH AN AUTUMN-LIKE
LOOK TO THE PATTERN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 523 PM MDT WED SEP 9 2015
HIGH PRESSURE OVER THE GREAT BASIN WILL BRING DRY AND CLEAR
CONDITIONS TO THE REGION FOR THE NEXT 24 HOURS. EXPECT VFR FLIGHT
CONDITIONS AT ALL SITES WITH LIGHT WINDS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...PF/JAM
LONG TERM...JAM
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1013 PM EDT WED SEP 9 2015
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MOVE INTO THE REGION TONIGHT BEFORE
STALLING NEAR THE SOUTH COAST THURSDAY. LOW PRESSURE WILL TRACK
SOUTH OF NEW ENGLAND THURSDAY INTO FRIDAY BRINGING WIDESPREAD
SHOWERS AND SOME THUNDERSTORMS...ALONG WITH HEAVY RAINFALL AT
TIMES. AS AN AREA OF LOW PRESSURE DEPARTS ON FRIDAY...A LULL IN
THE WEATHER WILL FOLLOW PRIOR TO AN ANOMALOUS WEATHER SYSTEM FOR
THE WEEKEND WHICH WILL LIKELY BRING THE AREA SOME RAIN FOR SUNDAY.
AS THE SYSTEM EXITS...MILDER WEATHER WILL FOLLOW WITH ABOVE-
AVERAGE TEMPERATURES BENEATH HIGH PRESSURE INTO NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
1012 PM UPDATE...
LINE OF SHOWERS AND THUNDERSTORMS PROGRESSING S/E ALONG AND AHEAD
OF WHAT APPEARS TO BE A PRE-FRONTAL TROUGH. APPEARS A COLD FRONT
IS STILL SITUATED WELL TO THE WEST BASED ON THE SURFACE DEWPOINTS.
LATEST MESOANALYSIS SHOWING A DECENT AMOUNT OF ENERGY TO WORK
WITH THIS EVENING...BUT NOT MUCH SHEAR OR INSTABILITY TO TRULY
HARNESS IT. RADAR TRENDS HAS BEEN FOR A SIGNIFICANT WEAKENING
TREND AS THE LINE OF SHOWERS MOVES EAST. EXPECTING THIS TREND TO
CONTINUE INTO THE VERY EARLY MORNING HOURS. THAT DOES NOT MEAN WE
WILL COMPLETELY RULE OUT A STRAY THUNDERSTORM...OR TWO.
TWEAKED POPS FOR THE NEXT SEVERAL HOURS. LATEST RUNS OF THE HRRR
SEEM TO HAVE A GOOD HANDLE ON THE LOCATION...BUT WERE A BIT SLOW
ON THE TIMING. SPED UP THE HRRR FOR A BASIS OF POPS FOR THIS
UPDATE. OTHERWISE...TWEAKS TEMPERATURES AND WINDS TO REFLECT THE
LATEST OBSERVED TRENDS.
A MILD NIGHT WITH INCREASING LOW CLOUDS AND THE POTENTIAL FOR
FOG...ESPECIALLY ACROSS THE S/SE-COAST. IN OTHER WORDS...CLOSE TO
A REPEAT OF LAST NIGHT. WILL HAVE TO MONITOR THE CONVECTIVE
POTENTIAL LATE TONIGHT...ESPECIALLY TOWARD THE SOUTH COAST. LOWS
AROUND 70 SHOULD WORK FOR MOST LOCATIONS.
&&
.SHORT TERM /THURSDAY NIGHT/...
*** LOCALLY HEAVY RAINFALL LIKELY THURSDAY INTO THURSDAY NIGHT ***
INSTABILITY AXIS DEVELOPS ACROSS THE COASTAL PLAIN IN THE MORNING
WITHIN THE THETA-E RIDGE AND WILL LIKELY SEE A GENERATION OF
SHOWERS AND TSTMS ACROSS E CT...RI AND SE MA THU MORNING ALONG THE
FRONTAL BOUNDARY. GIVEN PWATS INCREASING OVER 2 INCHES...LOCALLY
HEAVY RAINFALL IS POSSIBLE.
THE FRONT IS EXPECTED TO STALL NEAR THE SOUTH COAST AS LOW PRES
DEVELOPS OVER THE MID ATLC COAST...THEN LIFTING NE AND TRACKING
SOUTH OF NEW ENGLAND THU NIGHT. CLASSIC COLD SEASON SCENARIO WITH
LOW LEVEL FRONTOGENESIS AND CONVERGENCE DEVELOPING ON THE NW
PERIPHERY OF SFC LOW AND MID LEVEL CENTER WITHIN RIGHT ENTRANCE
REGION OF THE UPPER JET. THE BEST LOW LEVEL FORCING BECOMES
ALIGNED ACROSS W NEW ENG SO WE EXPECT FOCUS FOR HEAVIER RAINFALL
TO SHIFT TO THE WEST ACROSS W MA AND N CT DURING THU AFTERNOON
INTO THU NIGHT...EVENTUALLY REACHING THE COAST LATE THU NIGHT INTO
EARLY FRI. SFC INSTABILITY IS LIMITED IN THE WEST ON THE COOL
SIDE OF THE BOUNDARY BUT THERE IS ENOUGH ELEVATED INSTABILITY FOR
A FEW TSTMS. ANOMALOUS PWATS SUGGEST LOCALLY HEAVY RAINFALL WILL
BE THE PRIMARY THREAT WITH AREAS OF URBAN AND POOR DRAINAGE
FLOODING POSSIBLE. RAINFALL AMOUNTS OF 1 TO 2 INCHES WITH LOCALLY
HIGHER AMOUNTS POSSIBLE WITH AXIS OF HEAVIEST RAINFALL LIKELY
ACROSS WESTERN NEW ENGLAND. LESSER RAINFALL AMOUNTS EXPECTED IN
SE NEW ENG.
MUCH COOLER THU WITH MAX TEMPS MOSTLY IN THE 70S...BUT MAY REACH
80 ACROSS PORTIONS OF RI AND E MA. STILL QUITE HUMID IN E NEW ENG
WITH DEWPOINTS NEAR 70.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
HIGHLIGHTS...
* SHOWERS DISSIPATING THROUGH THE DAY FRIDAY
* A LULL IN THE WEATHER AROUND SATURDAY
* RETURN OF WET-WEATHER AND POSSIBLE THUNDERSTORMS FOR SUNDAY
* LOOKING DRY WITH ABOVE- AVERAGE TEMPERATURES INTO NEXT WEEK
DISCUSSION...
AN ANOMALOUS WEEKEND SETUP INTO EARLY NEXT WEEK THAT WARRANTS AN
ENSEMBLE FORECAST APPROACH. GOOD AGREEMENT ON A DEEP TROUGH PATTERN
EVOLVING INTO A QUASI CUT-OFF CLOSED LOW OVER THE OHIO RIVER VALLEY
REGION OVER THE WEEKEND...DEAMPLIFYING AS AN OPEN-WAVE OVER THE NE
EARLY NEXT WEEK. THEREAFTER ENSEMBLE MEANS CONTINUE TO ADVERTISE
RIDGING ACROSS THE REGION WITH PREFERRED TROUGHING TO THE W AND A
MAINTAINED AREA OF LOW PRESSURE OVER THE N ATLANTIC. APPEARANCES
WOULD LEAD TO BELIEVE THAT SUMMER IS NOT OVER QUITE YET AS THE 8-14
DAY FORECASTS FROM THE CLIMATE PREDICTION CENTER HAVE INCREASED
ABOVE-AVERAGE TEMPERATURE PROBABILITY. NORMALS FOR MID-SEPTEMBER ARE
AROUND THE LOW- TO MID-70S FOR HIGHS WITH LOW- TO MID-50S FOR LOWS.
FRIDAY INTO SATURDAY...
SOME INITIAL SHOWERS AND CLOUDY CONDITIONS TO START ON FRIDAY SHOULD
BREAK W TO E AS DRIER AIR MOVES IN AND SUBSIDENCE PROCEEDS BENEATH
RIDGING AHEAD OF THE CLOSED-LOW OVER THE OHIO RIVER VALLEY EXPECT A
LULL IN THE WEATHER-ACTIVITY FRIDAY INTO SATURDAY...THOUGH UNCERTAIN
AS TO WHEN IT WILL RE-EMERGE SATURDAY INTO SUNDAY. IT DOES APPEAR
BASED ON ENSEMBLE MEANS THAT THE RIDGE LIFTS NE SATURDAY-SUNDAY AS
THE CLOSED LOW IS RECAPTURED BY THE MARITIME FLOW DEAMPLIFYING AS
AN OPEN-WAVE MONDAY-TUESDAY. PROGRESS OF AN ACCOMPANYING WARM-
FRONTAL BOUNDARY ALONG WHICH THERE IS AN INCREASING UPSLOPE
MAGNITUDE OF HIGHER THETA-E AIR BENEATH GROWING DIFFLUENCE ALOFT
WARRANTS CHANCE POPS OVER THE MAJORITY OF THE AREA BEGINNING
SATURDAY NIGHT. WILL GO AHEAD WITH SOME ELEVATED THUNDER CHANCES
BUT KEEP THEM ISOLATED AS INSTABILITY APPEARS MARGINAL IN A
MODERATELY SHEARED ENVIRONMENT.
SUNDAY INTO MONDAY...
LIKELY RAIN WITH EMBEDDED THUNDER AND HEAVIER SHOWERS AS AN ENHANCED
H925-85 FLOW WRAPS CYCLONICALLY AROUND THE DEAMPLIFYING CLOSED-LOW
NE OF THE REGION. A QUASI-TROWALING SETUP COLLOCATED WITH STRONG
CONVERGENT ISENTROPIC-UPSLOPE SIGNATURES BENEATH DIFFLUENCE
ALOFT...THE POTENTIAL FLY-IN-THE-OINTMENT COULD BE THE
POSSIBILITY OF THE GREATER ENHANCED FORCING REMAINING W OF THE
REGION ASSOCIATED WITH THE DEAMPLIFYING CLOSED-LOW OVER THE E
GREAT LAKES AND/OR THE MODEL CONSENSUS OF NEW ENGLAND BEING
BENEATH THE RIGHT-EXIT REGION OF THE UPPER-LEVEL JET...YIELDING A
LESS FAVORABLE AREA OF LIFT.
ASIDE...THE APPARENT LOW-MID LEVEL LIFT AND CONVERGENCE OF THETA-E
YIELDS THE LIKELIHOOD OF RAIN. BUT THE QUICKLY-FOLLOWING PUNCH OF
DRIER AIR WRAPPING INTO THE OCCLUDING SYSTEM MAKES THE WET-WEATHER
PERIOD BRIEF. MOST OF THE ACTIVITY MAY RESIDE ON SUNDAY WITH DRY
WEATHER PREVAILING SUNDAY NIGHT.
ONLY A RENEWED CHANCE MAY EMERGE ON MONDAY ASSOCIATED WITH THE COMMA-
HEAD TROWAL OF THE LOW WHERE H85-5 TEMPERATURES DROP CONSIDERABLY.
H5 TEMPERATURES NEAR -20C. FOCUS ALONG A COLD FRONT AS POSSIBLY THE
BOUNDARY-LAYER DESTABILIZES AHEAD SUBSEQUENT OF THE PUNCH OF DRY AIR
COULD RESULT IN SOME LOW-TOPPED ACTIVITY. SOME SPATIAL VARIABILITY
WITH RESPECT TO ATMOSPHERIC FEATURES THUS ONLY WILLING TO GO WITH
CHANCE POPS MAINLY OUT TO THE W. WILL GO WITH AT OR BELOW-AVERAGE
TEMPERATURES FOR THE PERIOD.
PRESENTLY NOT SEEING MUCH IN THE WAY OF IMPACTS WITH RESPECT TO THE
WET-WEATHER. HIGHER THETA-E VALUES LOOK TO REMAIN OFFSHORE WITHIN
THE ANTICYCLONIC BRANCH OF THE WARM-CONVEYOR BELT...ALSO GREATER
INSTABILITY.
TUESDAY AND BEYOND...
DRY WEATHER AS RIDGING PROCEEDS PER AN ENSEMBLE-WEIGHTED FORECAST.
WILL LEAN TOWARDS AN ABOVE-AVERAGE TEMPERATURE FORECAST IN AGREEMENT
WITH THE CLIMATE PREDICTION CENTER. CONTINUED STRONG SIGNALS OF SW-
FLOW PREVAILING ALOFT ADVECTING NE ACROSS THE REGION A WARM-HUMID
AIRMASS.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY NIGHT/...
TONIGHT...MODERATE CONFIDENCE.
LOW-END VFR WITH MIX OF MVFR-IFR ASSOC WITH STRATUS MORE TOWARDS
THE S/SE-COAST. MONITORING LINE OF SHRA/TSRA SWEEPING S/E WHICH
SHOULD DISSIPATE E THOUGH REFOCUS S ALONG THE COAST LATE TONIGHT.
FOCUS FROM ORH-HYA AND POINTS SW TOWARDS MORNING. SW FLOW BACKING
W/NW WITH STORM-LINE PASSAGE. LINE WILL HANG ALONG S-COAST BY
MORNING.
THURSDAY...MODERATE CONFIDENCE.
IFR CONDITIONS ALONG THE S COAST IMPROVING TO MVFR/VFR. OTHERWISE...
VFR GRADUALLY LOWERING TO MVFR AS SHRA AND SCT TSRA DEVELOP. FOCUS
FOR SHRA/TSRA WILL INITIALLY BE ACROSS E CT/RI AND SE MA IN THE
MORNING...THEN GRADUALLY SHIFTING INTO W NEW ENGLAND IN THE AFTERNOON.
LOCALLY +RA POSSIBLE.
THURSDAY NIGHT...MODERATE CONFIDENCE.
CONDITIONS LOWERING TO IFR IN SHOWERS/TSTMS AND PATCHY FOG. LOCALLY
+RA POSSIBLE.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. LINE OF SHRA/TSRA THRU
THE TERMINAL AROUND 1Z.
OUTLOOK /FRIDAY THROUGH MONDAY/...
FRIDAY...MODERATE CONFIDENCE.
MVFR-IFR MIX ALONG WITH -SHRA LIFTS E ALLOWING CONDITIONS TO IMPROVE
THROUGH THE DAY. N-WINDS WITH THE POSSIBILITY OF 20 KT GUSTS ACROSS
THE E-COAST.
SATURDAY...MODERATE CONFIDENCE.
VFR. WINDS VEERING E/SE. DRY FORECAST.
SUNDAY...MODERATE CONFIDENCE.
MVFR-IFR MIX WITH E/SE-ONSHORE FLOW. RAIN LIKELY ACROSS THE REGION.
MAY ALSO CONTEND WITH SOME LLWS IMPACTS.
MONDAY...MODERATE CONFIDENCE.
IMPROVING TO VFR BEGINNING SUNDAY NIGHT. W/SW-WINDS WITH GUSTS UP TO
20 KTS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY NIGHT/...HIGH CONFIDENCE.
TONIGHT...VSBYS LOWERING IN PATCHY FOG TONIGHT S COASTAL WATERS.
WINDS LESSENING OUT OF THE SW. GUSTY WINDS DIMINISH ACROSS THE
EASTERN MA COASTAL WATERS THIS EVENING. WILL LIKELY BE ABLE TO
DROP THE SMALL CRAFT ADVISORY IN A FEW HOURS.
THU...WINDS BECOME NE LESS THAN 20 KT ACROSS E MA COASTAL WATERS
AS FRONT MOVES THROUGH BUT REMAINING S/SE OVER SOUTHERN WATERS.
VSBYS REDUCED IN SHOWERS AND POSSIBLE TSTMS AND FOG...ESPECIALLY
IN THE MORNING.
THU NIGHT...MAINLY E/NE WINDS BELOW SCA...BUT THERE IS LOW PROB
OF GUSTY NE WINDS DEVELOPING LATE ACROSS NE MA COASTAL WATERS.
VSBYS REDUCED AT TIMES IN SHOWERS/POSSIBLE TSTMS AND FOG.
OUTLOOK /FRIDAY THROUGH MONDAY/...
FRIDAY...MODERATE CONFIDENCE.
LOW PRESSURE LIFTING E. SHOWERS LINGER ACROSS THE WATER ALONG WITH
THE POSSIBILITY OF FOG. N-WINDS PREVAILING BACKING OUT OF THE NW.
INITIALLY COULD SEE GUSTS UP TO 25 KTS ACROSS THE E-WATERS LENDING
TO SEAS IN EXCESS OF 5-FEET. SMALL-CRAFT ADV MAY BE WARRANTED.
SATURDAY...MODERATE CONFIDENCE.
A LULL IN THE WEATHER. WINDS BECOME LIGHT WHILE VEERING E/SE. SHOULD
SEE SEAS SUBSIDE FOR THE PERIOD BELOW 5-FEET.
SUNDAY...MODERATE CONFIDENCE.
DEEPER AREA OF LOW PRESSURE TO THE W. WILL SEE AN ACCOMPANYING WARM
FRONT LIFT N ACROSS THE WATERS BRINGING WITH IT THE CHANCE OF RAIN
ALONG WITH INCREASING E/SE-ONSHORE WINDS. GUSTS UP TO 20 KTS
POSSIBLE. WAVE HEIGHTS BUILDING IN EXCESS OF 5-FEET PLAUSIBLE.
MONDAY...MODERATE CONFIDENCE.
THOUGH IMPROVING SUNDAY NIGHT...WINDS BACK OUT OF THE W/SW AND
REMAIN ROBUST WITH A STRONG AREA OF LOW PRESSURE SITUATED WELL TO
THE W ACROSS THE INTERIOR. ANOTHER DAY OF GUSTS UP TO 20 KTS WHILE
SEAS REMAIN AT OR IN EXCESS OF 5-FEET ON THE WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT THURSDAY FOR ANZ250.
&&
$$
SYNOPSIS...KJC/SIPPRELL
NEAR TERM...BELK/KJC/SIPPRELL
SHORT TERM...KJC
LONG TERM...SIPPRELL
AVIATION...BELK/KJC/SIPPRELL
MARINE...BELK/KJC/SIPPRELL
AREA FORECAST DISCUSSION
NWS ALBANY NY
128 PM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE NEAR THE MID ATLANTIC REGION WILL CONTINUE
TO PROVIDE UNSEASONABLY HOT WEATHER UNTIL TOMORROW. A WEAK
DISTURBANCE THIS AFTERNOON WILL BRING ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS FROM THE CAPITAL DISTRICT NORTH AND WEST. A COLD
FRONT WILL SLOWLY APPROACH FROM THE GREAT LAKES REGION AND MIDWEST
WEDNESDAY INTO THURSDAY WITH A GREATER THREAT OF SHOWERS AND
THUNDERSTORMS INCLUDING SOME LOCALLY HEAVY RAINFALL FOR EASTERN NEW
YORK AND WESTERN NEW ENGLAND THAT MAY CONTINUE UNTIL FRIDAY MORNING.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 128 PM EDT...A WEAK SFC WAVE CONTINUES TO MOVE ALONG A COLD
FRONT NEAR THE NY/CANADIAN BODER THAT EXTENDS EASTWARD INTO MAINE.
A WEAK SFC TROUGH OR WINDSHIFT BOUNDARY WITH THE WEAK DISTURBANCE
MOVING ALONG THE FRONT WILL FOCUS SOME ISOLD-SCT
SHOWERS/THUNDERSTORMS MAINLY FROM THE CAPITAL REGION...SCHOHARIE
VALLEY...AND NRN BERKSHIRES NORTHWARD THIS AFTERNOON.
THE POPS WERE INCREASED TO HIGH CHC VALUES ACROSS THE LAKE GEORGE
REGION INTO THE SRN DACKS...WHERE WE SEE SHOWERS/THUNDERSTORMS
CONTINUE TO POPS UP ON THE REGIONAL/LOCAL RADARS. THE CONVECTIVE
TEMP ON THE 12Z KALY SOUNDING WAS 90F SO EXPECT SOME ISOLD
SHOWER/THUNDERSTORM ACTIVITY A LITTLE FURTHER SOUTH...AS SEEN ON
THE KENX RADAR WITH SOME SHOWERS NEAR EXTREME SRN HERKIMER AND ERN
SCH COUNTY. THE LATEST SPC MESOANALYSIS FROM THE RAPID REFRESH INDICATES
SOME SBCAPE VALUES OF 1000-1500 J/KG OVER PARTS OF THE ALY FCST
AREA...THOUGH THE DEEP SHEAR IS VERY WEAK WITH 20 KTS GRAZING THE
NRN TIER /SRN DACK AND LAKE GEORGE REGION/. ACTIVITY FURTHER SOUTH
IS NOT LIKELY DUE TO THE MID LEVEL CAP AT 675-625 HPA ON THE KALY
SOUNDING. THE ISOLD/SCT SHRAS/TSRAS SHOULD DIMINISH LATE THIS PM
WITH THE DIURNAL HEATING DIMINISHING. THE LATEST HRRR COLUMNAR REF
PRODUCT SUPPORTS THIS TREND.
HUMIDITY LEVELS WILL BE UNCOMFORTABLE THIS AFTERNOON WITH SFC
DEWPTS IN THE M60S TO L70S. HIGHS IN THE U80S TO L90S LOOK ON
TRACK IN MANY OF THE VALLEY AREAS /A FEW M90S NEAR KPOU/...AND
U70S TO M80S OVER THE MTNS. APPARENT TEMPS ARE GENERALLY IN THE
LOWER TO M90S WITH A FEW U90S IN THE MID HUDSON VALLEY.
THE COLD FRONT WILL RETREAT NORTHWARD AS A WARM FRONT TONIGHT. AS
A RESULT EXPECT WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
THE NORTHERN THIRD OF THE FA TO DIMINISH OVERNIGHT. ANOTHER WARM
AND MUGGY NIGHT IS EXPECTED. LOWS TONIGHT WILL BE IN THE 60S TO
AROUND 70F.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
FOR WEDNESDAY AND WEDNESDAY NIGHT EXPECT AN INCREASING CHANCE OF
SHOWERS AND THUNDERSTORMS AS THE COLD FRONT MOVES FROM THE CENTRAL GREAT
LAKES WEDNESDAY MORNING INTO NORTHERN NEW YORK AND NORTHERN NEW
ENGLAND LATE WEDNESDAY. THE FRONTAL BOUNDARY WILL STALL ACROSS
EASTERN NEW YORK AND NORTHERN NEW ENGLAND WEDNESDAY NIGHT AS
SEVERAL WAVES OF LOW PRESSURE TRACK NORTHEAST ALONG THE BOUNDARY. PWATS
DURING THIS TIME INCREASE TO 1.75 TO 2+ INCHES...ML MUCAPES
INCREASE TO 500 TO 1000 J/KG WITH DEWPOINTS REMAINING MAINLY IN
THE 60S. AT THIS TIME NOT EXPECTING THE THUNDERSTORMS TO BE
SEVERE. HOWEVER AS WE GET INTO WEDNESDAY AND WEDNESDAY NIGHT HEAVY
DOWNPOURS WILL BE POSSIBLE WITH ANY THUNDERSTORMS ESPECIALLY GIVEN
THE HIGH PWAT VALUES. HIGHS ON WEDNESDAY ARE EXPECTED TO BE IN THE
80S WITH LOWS WEDNESDAY NIGHT IN 60S.
THURSDAY AND THURSDAY NIGHT LOOK WET AS THE SECOND WAVE OF LOW
PRESSURE TRACKS NORTHEAST ALONG THE STALLED FRONTAL BOUNDARY AND A
SECONDARY TROUGH OF LOW PRESSURE MOVES INTO NORTHERN NEW YORK.
PWATS REMAIN BETWEEN 1.5 AND 2 INCHES ON THURSDAY AND GRADUALLY
LOWER THURSDAY NIGHT. THINKING AT THIS TIME IS THAT THE HEAVIEST
RAINFALL WILL BE ACROSS THE SOUTHEASTERN TWO THIRDS OF THE FA ON
THURSDAY AND ACROSS THE SOUTHEASTERN THIRD OF THE FA THURSDAY
NIGHT. TOTAL RAINFALL AMOUNTS COULD EASILY REACH SEVERAL INCHES IN
SOME SPOTS. EXPECT HIGHS ON THURSDAY TO BE IN THE 70S TO LOWER 80S
WITH LOWS THURSDAY NIGHT IN THE MID 50S TO MID 60S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
A PATTERN CHANGE WILL BE UNDERWAY DURING THIS TIME PERIOD...AS THE
RECENT EASTERN NOAM RIDGE PUSHES FURTHER EAST OFF THE COAST...WHILE
AN UPPER LEVEL TROUGH DEVELOPS ACROSS THE NORTHERN PLAINS/UPPER
GREAT LAKES REGION. MODELS CONTINUE TO EXHIBIT SOME UNCERTAINTY AS
TO HOW THIS PATTERN CHANGE UNFOLDS...WITH THE 00Z/08 GFS AND GEFS
REMAINING SLIGHTLY MORE PROGRESSIVE WITH THE EVOLVING
PATTERN...WHILE THE 00Z/08 ECMWF IS SLOWER AND MORE AMPLIFIED. THIS
DIFFERENCE IS MOST NOTABLE FOR NEXT WEEKEND...AS THE GFS WOULD IMPLY
A QUICKER PASSAGE OF THE UPPER LEVEL TROUGH...ALONG WITH SCATTERED
RAIN SHOWERS FOR SAT...WHILE THE ECMWF WOULD IMPLY ENERGY HOLDING
BACK AND POTENTIALLY CARVING OUT A CLOSED MID LEVEL LOW CENTER WHICH
COULD BRING SHOWERS OR EVEN A WIDESPREAD STEADY RAINFALL FOR NEXT
SAT NT AND SUNDAY...ALONG WITH MUCH BELOW NORMAL TEMPS. TRENDS
OVERALL DO SEEM TO BE TOWARD A MORE PESSIMISTIC FORECAST...SO HAVE
INCREASED THE CHANCES FOR SHOWERS FROM SAT AFTERNOON INTO SUNDAY
ACROSS THE REGION.
HERE ARE SOME SPECIFICS...
FRI-SAT...SHOWERS MAY BE SLOW TO EXIT FRI MORNING...ESP FOR AREAS E
OF THE HUDSON RIVER...AS THE MID/UPPER LEVEL FLOW REMAINS SOMEWHAT
SOUTHWEST WITH THE RIDGE PERSISTING OFF THE EAST COAST...AND ALSO
THE PROXIMITY OF THE RIGHT ENTRANCE REGION TO AN UPPER LEVEL JET MAX
TRANSLATING ACROSS SOUTHEAST CANADA. IN FACT...THE LATEST 00Z/08
ECMWF SUGGESTS A WAVE DEVELOPS LONG THE DEPARTING FRONTAL
ZONE...ALLOWING FOR SHOWERS TO LINGER WELL INTO FRI MORNING FOR
AREAS NEAR AND EAST OF THE HUDSON RIVER. WILL THEREFORE KEEP CHC
POPS FOR MOST AREAS NEAR AND ESP E OF THE HUDSON RIVER IN THE
MORNING WITH SLIGHT CHC FURTHER N AND W...THEN DECREASE FROM W TO E
IN THE AFTERNOON. WILL THEN KEEP CONDITIONS MAINLY DRY FOR FRI
NT/SAT AM...WITH INCREASING CHANCES FOR SHOWERS SATURDAY AFTERNOON
FROM W TO E. AS FOR TEMPS...A COOLING TREND WILL BE UNDERWAY...WITH
MAX TEMPS GENERALLY IN THE LOWER/MID 70S FOR VALLEYS...AND 60S
ACROSS HIGHER TERRAIN. HOWEVER...EVEN COOLER MAX TEMPS COULD OCCUR
SHOULD CLOUDS/SHOWERS PERSIST LONGER THAN CURRENTLY EXPECTED FOR
FRI. FRI NT/SAT AM MINS SHOULD FALL INTO THE 50S FOR MOST
AREAS...WITH SOME 40S POSSIBLE ACROSS HIGHER ELEVATIONS WITHIN THE
SOUTHERN ADIRONDACKS.
SAT NT-SUN...MODELS CONTINUE TO TREND WETTER FOR THIS PERIOD...WITH
THE 00Z/08 ECMWF MOST AGGRESSIVE WITH A POSSIBLE STEADY RAINFALL AND
VERY COOL TEMPS. WILL KEEP CHC POPS FOR ALL AREAS DURING THIS
PERIOD. FOR TEMPS...EXPECT MAXES TO REACH 70-75 IN VALLEYS AND 60S
ACROSS HIGHER ELEVATIONS. HOWEVER...SHOULD A WIDESPREAD STEADY RAIN
OCCUR...MOST AREAS WOULD LIKELY REMAIN IN THE 60S ON SUNDAY...WITH
EVEN SOME UPPER 50S POSSIBLE IN HIGHER ELEVATIONS. SUN AM MINS
SHOULD MAINLY BE IN THE 50S.
SUN NT-MON...SOME SHOWERS MAY LINGER INTO SUN NT/MON AM...ESP ACROSS
WESTERN NEW ENGLAND...THEN TRENDING DRIER BY LATE MON. SUN NT/MON AM
MINS SHOULD MAINLY FALL INTO THE 50S...ALTHOUGH SOME 40S COULD OCCUR
IN HIGHER TERRAIN. MON MAX TEMPS SHOULD REACH THE LOWER/MID 70S IN
VALLEYS...AND 60S ACROSS HIGHER ELEVATIONS.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL REMAIN OFF THE MID ATLANTIC COAST INTO THIS
EVENING. A WEAK COLD FRONT WILL APPROACH FROM THE NORTH THIS
AFTERNOON AND EVENING...BEFORE RETREATING BACK NORTHWARD TONIGHT.
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS ASSOCIATED WITH AN
APPROACHING WEAK COLD FRONT ARE AROUND KGFL THIS AFTERNOON...BETWEEN
ROUGHLY 18Z-22Z/TUE. A VCSH HAS BEEN INDICATED IN THE KGFL TAF FOR
THIS POSSIBILITY. AT KALB...CAN NOT COMPLETELY RULE OUT ISOLATED
SHOWERS/THUNDERSTORMS BETWEEN 18Z-22Z/TUE...SO ADDED VCSH.
ELSEWHERE...GENERALLY DRY CONDITIONS ARE EXPECTED THROUGH THIS
EVENING.
FOR TONIGHT...SOME PATCHY FOG AND/OR LOW CLOUDS MAY DEVELOP AT
KPSF...AND PERHAPS KGFL AFTER 05Z/WED. THE BEST CHANCE FOR IFR
CONDITIONS WILL BE KPSF...WHICH HAS BEEN INCLUDED IN CURRENT TAFS.
PATCHY LOW CLOUDS COULD DEVELOP AT KPOU TOWARD 12Z/WED WITH MVFR
CIGS. AFTER 13Z...ANY FOG AND/OR LOW CLOUDS SHOULD BURN OFF AND VFR
CONDITIONS SHOULD PREVAIL.
LIGHT SOUTHWEST TO WEST WINDS AROUND 5-10 KT THIS AFTERNOON. THERE
COULD BE SOME SLIGHTLY STRONGER GUSTS UP TO 15 KT THIS AFTERNOON.
WINDS WILL THEN BECOME LIGHT/VARIABLE TOWARD AND AFTER
SUNSET...ALTHOUGH A SOUTH WIND MAY PERSIST AND/OR REDEVELOP AT KALB
OVERNIGHT AT 5-10 KT. SOUTH TO SOUTHWEST WINDS AT LESS THAN 10 KT
DEVELOPING WEDNESDAY MORNING.
OUTLOOK...
WEDNESDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
THURSDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
FRIDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
FRIDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
&&
.FIRE WEATHER...
HIGH PRESSURE NEAR THE MID ATLANTIC REGION WILL CONTINUE TO
PROVIDE UNSEASONABLY HOT WEATHER UNTIL WEDNESDAY. A WEAK
DISTURBANCE TODAY WILL BRING ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS FROM THE CAPITAL DISTRICT NORTH AND WEST. A COLD
FRONT WILL SLOWLY APPROACH FROM THE GREAT LAKES REGION AND MIDWEST
WEDNESDAY INTO THURSDAY WITH A GREATER THREAT OF SHOWERS AND
THUNDERSTORMS INCLUDING SOME LOCALLY HEAVY RAINFALL FOR EASTERN
NEW YORK AND WESTERN NEW ENGLAND.
RELATIVE HUMIDITIES WILL DROP TO 35 TO 65 PERCENT THIS
AFTERNOON...RECOVER TO 70 TO 100 PERCENT TONIGHT...AND DROP TO 35
TO 60 PERCENT ON WEDNESDAY.
WINDS TODAY WILL BE SOUTHWEST TO WEST AT 5 TO 10 MPH...LIGHT AND
VARIABLE TONIGHT...AND SOUTH TO SOUTHWEST AT 5 TO 10 MPH ON
WEDNESDAY.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH WEDNESDAY. THE
END OF THE WEEK LOOKS VERY WET AND EXCESSIVE RAINFALL IS POSSIBLE
SO THE THREAT OF FLOODING WILL BE INCREASING.
A HOT AND HUMID AIR MASS WILL BE OVER THE REGION INTO THE MID
WEEK. SOME ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE MAINLY FROM THE GREATER CAPITAL DISTRICT NORTH AND WEST
THROUGH WEDNESDAY.
A MORE WIDESPREAD CHANCE OF SHOWERS AND THUNDERSTORMS WILL OCCUR
AHEAD OF A COLD FRONT WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. THE
COLD FRONT IS EXPECTED TO SLOWLY MOVE ACROSS THE REGION THURSDAY
NIGHT. GUIDANCE INDICATES PWATS SHOULD RISE TO 1.5 TO 2 INCHES
AHEAD OF THE BOUNDARY...SO HEAVY DOWNPOURS ARE TO BE EXPECTED WITH
SOME THUNDERSTORMS. SOME POOR DRAINAGE FLOODING...AND PONDING OF
WATER ON ROADWAYS WILL BE POSSIBLE AND HEAVY RAINFALL MAY LINGER
INTO FRIDAY AS A WAVE OF LOW PRESSURE DEVELOPS ALONG THE FRONT AND
TRACKS NORTHEASTWARD. SEVERAL INCHES OF RAIN TOTAL ARE POSSIBLE IN
SOME SPOTS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.CLIMATE...
RECORD HIGH TEMPERATURES WERE BROKEN AT POUGHKEEPSIE AND GLENS FALLS
MONDAY SEPTEMBER 7TH.
POUGHKEEPSIE: HIGH 95 DEGREES BREAKING THE OLD RECORD OF 90 DEGREES
SET IN 2001. NOTE...RECORDS FOR POUGHKEEPSIE DATE BACK TO
1949...HOWEVER DATA IS MISSING FROM JANUARY 1993 THROUGH JULY
2000.
GLENS FALLS: HIGH 92 DEGREES BREAKING THE OLD RECORD OF 89 DEGREES
SET IN 2007. NOTE...RECORDS FOR GLENS FALLS DATE BACK TO 1949.
AT ALBANY THE HIGH WAS 92 DEGREES. THIS FALLS SHORT OF THE RECORD
FOR SEPTEMBER 7TH OF 96 DEGREES SET BACK IN 1945. NOTE...RECORDS
FOR ALBANY DATE BACK TO 1874.
RECORD HIGH TEMPERATURES...
SEPTEMBER 8TH...
ALBANY: 93 DEGREES 1945
GLENS FALLS: 90 DEGREES 1959
POUGHKEEPSIE: 92 DEGREES 2007
SEPTEMBER 9TH...
ALBANY: 94 DEGREES 1959
GLENS FALLS: 92 DEGREES 1959
POUGHKEEPSIE: 91 DEGREES 1989
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...11/WASULA
NEAR TERM...11/WASULA
SHORT TERM...11
LONG TERM...KL
AVIATION...KL
FIRE WEATHER...11
HYDROLOGY...11/WASULA
CLIMATE...IAA
AREA FORECAST DISCUSSION
NWS MIAMI FL
146 PM EDT TUE SEP 8 2015
.AVIATION...
CONVECTION HAS BEEN VERY SLOW TO GET GOING AND THUS FAR HAS BEEN
WELL INLAND FROM THE TERMINALS AS THE EAST COAST SEA BREEZE HAS
PUSHED INLAND AIDED FROM EARLIER OUTFLOW BOUNDARIES. HOWEVER,
SOUTH-SOUTHWEST STEERING FLOW COULD EASILY MOVE CELLS BACK CLOSER
TO THE EAST COAST AND THE HRRR HINTS AT THIS AFT 19-20Z SO A
LITTLE HESITANT TO REMOVE FROM THE FORECAST. MOST ACTIVITY WILL
MORE LIKELY BE INLAND LATER THIS AFTERNOON. SURFACE WIND WILL ONCE
AGAIN BECOME L/V AFT 00Z WITH VFR CONDITIONS EXPECTED OVERNIGHT.
KOB
&&
.PREV DISCUSSION... /ISSUED 1019 AM EDT TUE SEP 8 2015/
UPDATE...
MID LEVEL TROUGH CONTINUES TO DRIFT NORTHWEST ACROSS THE NORTHEAST
GULF OF MEXICO WITH ATLANTIC RIDGE BUILDING BACK TO THE WEST OVER
SOUTH FLORIDA. THIS HAS RESULTED IN A CONTINUATION OF DEEP
SOUTHERLY MOIST AIR BUT WITH SLIGHT WARMING ALOFT. THEREFORE,
ACTIVITY WILL NOT BE AS ROBUST AS YESTERDAY BUT COULD STILL GET
TORRENTIAL DOWNPOURS ESPECIALLY WHEREVER CONVERGENT BOUNDARIES MAY
SET UP. SO WILL LEAVE MENTION OF FLOODING POTENTIAL IN THE HWO BUT
WILL REMOVE STRONG WIND GUSTS DUE TO A LACK OF ANY DISCERNIBLE DRY
LAYERS OBSERVED FROM THE 12Z MFL SOUNDING.
KOB
PREV DISCUSSION... /ISSUED 736 AM EDT TUE SEP 8 2015/
AVIATION...
A DEEP SOUTHERLY FLOW OF TROPICAL AIR WILL INFLUENCE SOUTH FLORIDA
THROUGH THE FORECAST PERIOD WITH SEA BREEZES DEVELOPING ALONG BOTH
COASTS. THUNDERSTORMS WILL NOT BE QUITE AS ACTIVE AS YESTERDAY
WITH SOME WARMING ALOFT AND WILL MOSTLY MOVE INLAND AWAY FROM THE
TERMINALS. THUS, HAVE KEPT VCTS IN FOR ALL TAF SITES FOR THE LATE
MORNING AND EARLY AFTERNOON.
KOB
PREV DISCUSSION... /ISSUED 306 AM EDT TUE SEP 8 2015/
LATE SUMMER TIME WEATHER PATTERN CONTINUES ACROSS SOUTH FLORIDA
THIS WEEK...
SHORT TERM...
LOW PRESSURE OVER THE NORTHEAST GULF OF MEXICO WILL CONTINUE TO
MOVE NORTHWARD TODAY AND DISSIPATE OVER THE SOUTHEASTERN UNITED
STATES TONIGHT ALLOWING FOR HIGH PRESSURE TO BUILD INTO THE
FLORIDA PENINSULA FROM THE WESTERN ATLANTIC WATERS. THIS WILL
ALLOW FOR THE WIND FLOW OVER SOUTH FLORIDA TO BE SOUTH/SOUTHEAST
AND ALLOW FOR THE SEA BREEZES TO DEVELOP AND PUSH INLAND TODAY.
THEREFORE...THE BEST COVERAGE OF SHOWERS AND THUNDERSTORMS TODAY
WILL BE OVER THE INTERIOR AREAS OF SOUTH FLORIDA.
THE HIGH WILL REMAIN OVER THE WESTERN ATLANTIC WATERS EXTENDING
INTO CENTRAL FLORIDA FOR THE MIDDLE TO END OF THIS WEEK.
THIS WILL KEEP SOUTH FLORIDA IN A EAST TO SOUTHEAST WIND FLOW
FOCUSING THE SHOWERS AND THUNDERSTORM ACTIVITY OVER THE INTERIOR
AND WEST COAST METRO AREAS EACH DAY. THEREFORE...THE HIGHEST POPS
WILL BE OVER THE INTERIOR AND WEST COAST METRO AREAS EACH DAY THIS
WEEK.
LONG TERM...
THE LONG RANGE MODELS ARE SHOWING A COLD FRONT TO MOVE SOUTHWARD
INTO THE SOUTHEAST UNITED STATES THIS WEEKEND AND STALL OUT.
THIS WILL PUSH THE HIGH SOUTHWARD INTO SOUTH FLORIDA THIS WEEKEND
ALLOWING FOR THE WIND FLOW TO BECOME MORE SOUTHERLY ALONG WITH
MORE DEEPER TROPICAL MOISTURE WORKING INTO THE AREA FROM THE
SOUTH. THEREFORE...THE HIGHEST POPS WILL SHIFT TO THE NORTHERN
AREAS OF SOUTH FLORIDA THIS WEEKEND BUT ALL OF SOUTH FLORIDA
SHOULD SEE SCATTERED COVERAGE IN POPS.
MARINE...
THE WINDS WILL BE SOUTH TO SOUTHEAST TODAY BEFORE SWINGING MORE
TO THE SOUTHEAST DIRECTION TONIGHT THROUGH REST OF THE WEEK.
THE WIND SPEEDS WILL BE LESS THAN 10 KNOTS TODAY THROUGH REST OF
THE WEEK. THIS WILL KEEP THE SEAS AT 2 FEET OR LESS IN BOTH THE
ATLANTIC AND GULF WATERS OF SOUTH FLORIDA THROUGH THE WEEK.
THEREFORE...BOATING CONDITIONS SHOULD BE GOOD ACROSS SOUTH FLORIDA
WATERS OUTSIDE OF ANY SHOWERS OR THUNDERSTORMS.
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1155 PM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 944 PM CDT MON SEP 7 2015
AT THE PRESENT TIME I DID NOT MAKE LARGE SCALE CHANGES TO THE
GOING FORECAST HOWEVER...THE LATEST HRRR IS SUGGESTING THAT THE
HEAVY RAINFALL WOULD BE FOCUSED MORE ACROSS NORTHERN IOWA. ONGOING
STORMS ACROSS NEBRASKA/KANSAS HAS BEEN FIZZLING AS THEY CROSS INTO
IOWA. IT APPEARS THESE STORMS HAVE FIRED ALONG AN INSTABILITY AXIS
WHERE MOISTURE TRANSPORT AS BEEN PRETTY GOOD. AS A LOW LEVEL JET
DEVELOPS I STILL EXPECT STORMS TO EVENTUALLY WORK ACROSS SOUTHERN
IOWA OVERNIGHT AND GIVEN THE HEAVY RAINFALL WE RECEIVED LAST NIGHT
IT WON`T TAKE MUCH TO PRODUCE FLASH FLOODING. HOWEVER...A SURFACE WARM
FRONT IS SITUATED ACROSS NORTHERN IOWA AND THERE IS AN APPROACHING
SHORTWAVE COMING ACROSS CEN NEB/SOUTH DAKOTA WHICH SHOULD BE
MOVING INTO NORTHERN IOWA OVERNIGHT. CONVECTION HAS BEEN RATHER
ROBUST IN THIS AREA THIS EVENING. MOISTURE TRANSPORT HAS INCREASED
INTO THIS AREA AND ONCE A SW LOW LEVEL JET GETS GOING CONVECTION
SHOULD INCREASE IN THIS AREA AND OVERSPREAD NORTHERN IOWA. THE
HRRR HAS LATCHED ONTO THIS IDEA AND IT CERTAINLY APPEARS
REASONABLE TO ME. I HAVE INCREASED POPS AND QPF FOR NOW BUT WOULD
NOT BE SURPRISED TO SEE THE HEAVY RAIN AREA SHIFTED FURTHER NORTH.
WILL BE WATCHING THE EVOLUTION OF THIS WITH TIME BUT FOR NOW I`M
BECOMING INCREASINGLY CONCERNED ABOUT NORTHERN IOWA.
&&
.SHORT TERM /TONIGHT/...
ISSUED AT 327 PM CDT MON SEP 7 2015
HEAVY RAIN REMAINS THE CONCERN OF THE OVERNIGHT FORECAST.
OVERNIGHT CONVECTION HAS LAID OUT AN OUTFLOW BOUNDARY OVER
NORTHERN MISSOURI WHICH IS TIED BACK INTO THE LOW OVER KANSAS.
THE SYNOPTIC BOUNDARY IS STILL OVER IOWA...STRETCHING FROM NEAR
PRAIRIE DU CHIEN BACK WEST TO NEAR DENISON. H850 FRONT IS ALSO
SITUATED OVER IOWA NOW. THE MODELS ARE HAVING DIFFICULTY WITH THE
EVOLUTION OF THE CONVECTION TONIGHT...BUT AN OVERALL CONSENSUS IS
FOR THE CENTRAL AND SOUTH TO RECEIVE THE BALANCE OF THE FORCING
AND THUS...RAINFALL. THE NAM WAS FARTHER SOUTH WITH THE MAIN QPF
AXIS TONIGHT...WHILE THE GFS LOOKS VERY SIMILAR TO LAST NIGHTS
FARTHER NORTH PLACEMENT OVER IOWA...THIS TIME RIGHT OVER THE I80
CORRIDOR. THE OTHER MESO MODELS SHOW A VARIETY OF SOLUTIONS...WITH
THE HIRES ARW HAVING A FOCUS FOR TWO AREAS OF HEAVY RAINFALL...ONE
NEARER THE IA/MO BORDER AND ONE ALONG THE I80 CORRIDOR. THE LATEST
HRRR RUN IS SHOWING TWO MAXIMA AS WELL...WITH A LESS ORGANIZED
CLUSTERING THAN THE OTHER MODELS MENTIONED. A NUMBER OF FACTORS
ARE POINTING TOWARD TWO MAXIMA...ONE THE H850 BOUNDARY IS ALREADY
BECOMING ACTIVE OVER CENTRAL NEBRASKA AND THERE IS ALSO SOME
DEVELOPMENT ALONG THE TRIPLE POINT IN SOUTHEAST NEBRASKA NEARER
THE SFC LOW...COOL FRONT...AND OUTFLOW BOUNDARY INTERSECTION. THE
SOUTHERN CLUSTER WILL FOLLOW THE BOUNDARY UNTIL IT IS LIFTED NORTH
THIS EVENING...WHILE THE NORTHERN AREA WILL CONTINUE TO FILL IN
THROUGH THE EVENING HOURS. AS THE LOW LEVEL JET KICKS IN BETWEEN
02-03Z THIS EVENING...THE COVERAGE AND INTENSITY OF THE CONVECTION
SHOULD INCREASE. NOTHING MUCH HAS CHANGED WITH REGARD TO THE
AVAILABLE MOISTURE...STILL RUNNING ABOUT 2.30 INCH PWATS AT 06Z
OVER THE SOUTH THIRD WITH WARM CLOUD DEPTHS PUSHING 13.8 KFT AT
OVERNIGHT. THE SCENARIO IS PRETTY MUCH THE SAME FOR EFFICIENT
RAINFALL PROCESSES TONIGHT...SO HAVE GENERALLY GONE ABOUT 1 TO 2
INCHES ACROSS THE SOUTH WITH THE EXPECTATION THAT THERE MAY BE
SOME TOTALS IN THE 4 TO 5 INCH RANGE BY MORNING. AS THE LOW
PUNCHES NORTH THIS EVENING...LOWS WILL REMAIN WARM SOUTH/SOUTHEAST
WITH SLIGHTLY COOLER NORTHWEST. SHOWERS WILL HOLD ON IN THE
SOUTHEAST. WITH LIGHT WINDS IN THE MORNING...PATCHY TO AREAS OF
FOG MAY ALSO DEVELOP.
.LONG TERM /TUESDAY THROUGH MONDAY/...
ISSUED AT 327 PM CDT MON SEP 7 2015
THE LONG TERM FORECAST GROWS GENERALLY MORE AUTUMNAL AS A SERIES
OF NORTHERN STREAM MID/UPPER LEVEL TROUGHS ROUNDING BROAD CYCLONIC
FLOW KEEP THE MORE SUMMERLIKE WEATHER BENEATH A LARGE RIDGE
SHUNTED OFF TO OUR SOUTH AND WEST. THE FIRST OF THESE TROUGHS WILL
MOVE OVERHEAD ON TUESDAY...POSSIBLY GENERATING SOME ELEVATED
SHOWERS AND THUNDERSTORMS MAINLY ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA. HOWEVER...THE SURFACE FRONT SHOULD BE BLOWN THROUGH
INTO MISSOURI BY TONIGHTS CONVECTION AND ANY SEVERE WEATHER OR
HEAVY RAIN THREAT WILL BE SOMEWHAT DIMINISHED TOMORROW. THIS
INITIAL TROUGH WILL ALSO FINALLY SCOUR OUT OUR WARM AND JUICY
AIRMASS OUT OF IOWA...WITH A COOL AREA OF HIGH PRESSURE BRINGING
DRY AND PLEASANT WEATHER BY WEDNESDAY.
THE SECOND...SUBSTANTIALLY STRONGER MID/UPPER LEVEL TROUGH WILL
DEEPEN AS IT MOVES OVER MINNESOTA AND WISCONSIN AROUND THURSDAY
NIGHT AND FRIDAY. THIS WILL PUSH A MORE PRONOUNCED REINFORCING
COLD FRONT ACROSS IOWA DURING THIS TIME FRAME...BRINGING
CONSIDERABLY COOLER WEATHER FROM FRIDAY INTO SATURDAY. THE PASSAGE
OF THE FRONT WILL LIKELY GENERATE ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS AROUND THURSDAY NIGHT...BUT TIMING DIFFERENCES
AMONG THE MODELS PROHIBIT GOING HIGHER THAN 20 OR 30 POPS AT THIS
TIME. WHILE THE FORCING AND WIND FIELDS ASSOCIATED WITH THE
PASSAGE OF THIS SYSTEM MAY BE ROBUST...INSTABILITY SHOULD BE
LIMITED MITIGATING ANY SEVERE WEATHER THREAT. THE ALTERNATING
PATTERN OF TROUGHS AND RIDGES WILL CONTINUE FROM THE WEEKEND INTO
NEXT WEEK WITH SUNSHINE AND RECOVERING TEMPERATURES ON SUNDAY
FOLLOWED BY ANOTHER COLD FRONT ON MONDAY OR MONDAY NIGHT...AND
POSSIBLY ANOTHER AROUND WEDNESDAY OR THURSDAY OF NEXT WEEK THOUGH
THAT IS BEYOND THE SEVEN DAY FORECAST PERIOD.
OUTSIDE OF SOME LINGERING POTENTIAL FOR STRONG STORMS OR HEAVY
RAIN ON TUESDAY...WHICH SHOULD BE AN ISOLATED THREAT...AND THE
LOW POSSIBILITY OF PERHAPS A COUPLE OF BRIEFLY STRONG STORMS WITH
THE FRONT AROUND THURSDAY NIGHT...THERE IS LITTLE IN THE WAY OF
HAZARDOUS OR HEADLINE INDUCING WEATHER DURING THE NEXT SEVEN DAYS.
OVERALL IT WILL BE COOLER...DRY...AND STARTING TO FEEL LIKE FALL
ACROSS IOWA.
&&
.AVIATION...08/06Z
ISSUED AT 1155 PM CDT MON SEP 7 2015
COMPLICATED FORECAST WITH A STALLED BOUNDARY ACROSS CENTRAL IOWA AND
AN APPROACHING SHORTWAVE WITH AN INCREASING LOW LEVEL JET. MAIN
AREA OF CONVECTION WILL BE STORMS BLOSSOMING ACROSS NEBRASKA PUSHING
INTO TAF LOCATIONS LATE TONIGHT...08Z-12Z. A SECOND AREA OF
CONVECTION OVER FSD AREA WILL MOVE ACROSS NORTHERN IOWA. ALTHOUGH
HEAVY RAIN IS POSSIBLE ANYWHERE ACROSS IOWA THE BETTER POTENTIAL
WILL REMAIN ACROSS THE SOUTHERN IOWA. MVFR WITH LCL IFR CONDITIONS
WILL PERSIST THROUGH 12Z-15Z WITH SLOW IMPROVEMENT NW TO SE. SFC
FLOW WILL BE EAST TO SOUTHEAST THEN BECOME NORTHERLY.
&&
.HYDROLOGY...
ISSUED AT 327 PM CDT MON SEP 7 2015
EVEN WITH THE RESPITE IN RAIN TODAY...WE STILL REMAIN PRIMED FOR
ADDITIONAL RISES IN RIVERS OVER THE NEXT SEVERAL DAYS.
LAST NIGHTS EXTREME RAINS WERE FAIRLY LOCALIZED IN THE RACCOON RIVER
BASIN AND WITH ADDITIONAL RAINFALL TONIGHT...SOME LOCATIONS MAY
REACH MODERATE CATEGORY ACROSS CENTRAL IOWA. CONFIDENCE ON TONIGHTS
RAINFALL IS SOMEWHAT LIMITED DUE TO LAST NIGHTS CONVECTION AND THE
EXPECTED RECOVERY OF STORMS LATER TONIGHT FARTHER WEST IN NEBRASKA.
IF THE STORMS FOLLOW A SIMILAR EVOLUTION TO LAST NIGHT...THE RACCOON
RIVER WOULD BE FURTHER AFFECTED...ALONG WITH SOME IMPACTS FOR
STREAMS AND CREEKS OVER CENTRAL AND SOUTHERN IOWA...LEADING TO
LOCALIZED FLASH FLOODING OVERNIGHT AND ADDITIONAL RISES TO MAIN STEM
RIVERS AND POSSIBLE RIVER FLOOD WARNINGS IN THE NEXT FEW DAYS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 7 AM CDT TUESDAY FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BOONE-CARROLL-CASS-CLARKE-CRAWFORD-DALLAS-
DAVIS-DECATUR-GREENE-GUTHRIE-JASPER-LUCAS-MADISON-MAHASKA-MARION-
MARSHALL-MONROE-POLK-POWESHIEK-RINGGOLD-STORY-TAMA-TAYLOR-UNION-
WAPELLO-WARREN-WAYNE.
&&
$$
UPDATE...FAB
SHORT TERM...REV
LONG TERM...LEE
AVIATION...FAB
HYDROLOGY...REV
AREA FORECAST DISCUSSION
NWS GOODLAND KS
354 PM MDT TUE SEP 8 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 222 PM MDT TUE SEP 8 2015
WV IMAGERY AND RAP H5 ANALYSIS SHOWS NW FLOW ACROSS CENTRAL ROCKIES
AND OVER OUR CWA ON WESTERN EXTENT OF LARGE SCALE TROUGH. AXIS OF
SUBSIDENCE IS CURRENTLY IN PLACE AS A SHORTWAVE TROUGH IS MOVING
ACROSS CENTRAL KANSAS. AT THE SURFACE HIGH PRESSURE IS BUILDING INTO
OUR CWA FROM THE NORTHERN PLAINS WITH A COLD FRONT THAT MOVED
THROUGH OUR CWA EARLY THIS MORNING EXTENDING FROM NORTHEAST KANSAS
THROUGH SOUTH CENTRAL KANSAS.
TONIGHT...DRY CONDITIONS SHOULD PERSIST THROUGH THE OVERNIGHT PERIOD
WITH SUBSIDENCE PERSISTING THROUGH MOST OF THE NIGHT...AND DEEP DRY
AIR MASS IN PLACE. EARLY IN THE EVENING STEEP LAPSE RATES LEE TROUGH
REBUILDS ALONG KS/CO BORDER OVERNIGHT WITH SOUTHERLY FLOW BRINING
HIGH BL MOISTURE IN PLACE. TREND IN GUIDANCE HAS BEEN TO TO SHOW
BETTER MIXING AND BL RH STAYING UP LIMITING FOG POTENTIAL. NAM AND
RAP DO STILL SHOW SOME REDUCED VISIBILITIES AND I FELT COMFORTABLE
KEEPING MENTION IN FORECAST FOR NOW.
WEDNESDAY...A QUICK MOVING/WEAK SHORTWAVE TROUGH WILL ROTATE THROUGH
NW FLOW JUST NORTH OF OUR CWA. DRY LAYER IN PLACE LOWERS OVERALL
CONFIDENCE IN COVERAGE...HOWEVER GUIDANCE IS SHOWING INITIATION
EITHER UPSTREAM OR ALONG SURFACE TROUGH AND TRACKING EAST ACROSS THE
NORTHERN HALF OF OUR CWA. IF A CELL WERE TO DEVELOP ML CAPE VALUES
AROUND 2000 J/KG AND EFFECTIVE SHEAR VALUES AROUND 35KT COULD
SUPPORT A LIMITED SEVERE THREAT. IM JUST NOT SURE IF ANYTHING WILL
EVEN DEVELOP CONSIDERING THE DRY AIR MASS IN PLACE. I KEPT SLIGHT
CHANCE POPS IN THE AFTERNOON...COVERING POTENTIAL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 255 PM MDT TUE SEP 8 2015
SEVERAL SHORT WAVE TROUGHS MOVE ACROSS THE CENTRAL HIGH PLAINS
REGION WEDNESDAY NIGHT...THURSDAY NIGHT...AND FRIDAY EVENING. THE
UPPER PATTERN BECOMES MORE AMPLIFIED AS THE SHORT WAVE TROUGHS
DIVE INTO THE BASE OF THE MAIN UPPER TROUGH POSITIONED OVER THE
MISSISSIPPI VALLEY REGION AS THE UPPER RIDGE AMPLIFIES OVER THE
WESTERN UNITED STATES THURSDAY THROUGH FRIDAY NIGHT AND
TRANSITIONS EASTWARD OVER THE ROCKIES AND HIGH PLAINS SATURDAY
NIGHT.
WITH A SURFACE TROUGH/FRONTAL BOUNDARY REMAINING IN THE VICINITY
OF THE FORECAST AREA THESE SHORT WAVE TROUGHS TRANSITIONING THE
REGION WILL HELP ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOP EACH DAY FROM LATE WEDNESDAY THROUGH EARLY FRIDAY. BY LATE
FRIDAY THE FRONTAL BOUNDARY HAS PUSHED SOUTH OF THE REGION AND
SURFACE HIGH PRESSURE MOVES INTO THE AREA. TEMPERATURES WILL WARM
THROUGH THURSDAY AHEAD OF THE FRONT WITH HIGH TEMPERATURES ONLY
EXPECTED TO REACH IN TO THE 70S ON FRIDAY. TEMPERATURES WILL
REBOUND QUICKLY THROUGH THE WEEKEND AND INTO NEXT WEEK AS
SOUTHERLY NEAR SURFACE FLOW RETURNS AND THE REGION REMAINS UNDER
WEAK RIDGING THROUGH THE WEEKEND AS THE UPPER PATTERN UNDERGOES A
TRANSITION TO A RIDGE OVER THE EASTERN HALF OF THE UNITED STATES
WHILE THE NEXT SIGNIFICANT LONG WAVE TROUGH DEEPENS OVER THE
WESTERN UNITES STATES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1122 AM MDT TUE SEP 8 2015
MVFR CIGS AROUND 1500 FT ARE STILL LIKELY TO ADVECT ACROSS THE
KMCK DURING THE EARLY PART OF THE TAF PERIOD WITH VIS SATELLITE
AND UPSTREAM OBS SHOWING THIS STRATUS FIELD MOVING SE WITH LOWEST
OBS BELOW 1000 FT. SHORT RANGE GUIDANCE INDICATES THIS SHOULD
CONTINUE TO DISSIPATE WITH DAYTIME HEATING...SO I WAS NOT
CONFIDENT ENOUGH TO CARRY MENTION OF MORE THAN TEMPO MVFR. VFR
WILL PREVAIL AT KGLD THROUGH THE FIRST 12 HR OF THE TAF PERIOD.
AFTER 06Z TONIGHT SOUTHERLY FLOW WILL BRING INCREASING
MOISTURE ONCE AGAIN TO THE REGION AND THE POSSIBILITY FOR
FOG/STRATUS. STRONGEST SIGNAL IN GUIDANCE IS IN SW NEBRASKA AND
SOUTH OF INTERSTATE 70...HOWEVER BOTH TERMINALS WILL LIKELY SEE A
PERIOD OF AT LEAST MVFR CONDITIONS AROUND SUNRISE. CONFIDENCE IS
TOO LOW TO INCLUDE LOWER CONDITIONS DUE TO A LACK OF
CONSENSUS/CONSISTENCY IN LOCATION OF BEST MOISTURE/LOWEST MIXING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
222 PM MDT TUE SEP 8 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 222 PM MDT TUE SEP 8 2015
WV IMAGERY AND RAP H5 ANALYSIS SHOWS NW FLOW ACROSS CENTRAL ROCKIES
AND OVER OUR CWA ON WESTERN EXTENT OF LARGE SCALE TROUGH. AXIS OF
SUBSIDENCE IS CURRENTLY IN PLACE AS A SHORTWAVE TROUGH IS MOVING
ACROSS CENTRAL KANSAS. AT THE SURFACE HIGH PRESSURE IS BUILDING INTO
OUR CWA FROM THE NORTHERN PLAINS WITH A COLD FRONT THAT MOVED
THROUGH OUR CWA EARLY THIS MORNING EXTENDING FROM NORTHEAST KANSAS
THROUGH SOUTH CENTRAL KANSAS.
TONIGHT...DRY CONDITIONS SHOULD PERSIST THROUGH THE OVERNIGHT PERIOD
WITH SUBSIDENCE PERSISTING THROUGH MOST OF THE NIGHT...AND DEEP DRY
AIR MASS IN PLACE. EARLY IN THE EVENING STEEP LAPSE RATES LEE TROUGH
REBUILDS ALONG KS/CO BORDER OVERNIGHT WITH SOUTHERLY FLOW BRINING
HIGH BL MOISTURE IN PLACE. TREND IN GUIDANCE HAS BEEN TO TO SHOW
BETTER MIXING AND BL RH STAYING UP LIMITING FOG POTENTIAL. NAM AND
RAP DO STILL SHOW SOME REDUCED VISIBILITIES AND I FELT COMFORTABLE
KEEPING MENTION IN FORECAST FOR NOW.
WEDNESDAY...A QUICK MOVING/WEAK SHORTWAVE TROUGH WILL ROTATE THROUGH
NW FLOW JUST NORTH OF OUR CWA. DRY LAYER IN PLACE LOWERS OVERALL
CONFIDENCE IN COVERAGE...HOWEVER GUIDANCE IS SHOWING INITIATION
EITHER UPSTREAM OR ALONG SURFACE TROUGH AND TRACKING EAST ACROSS THE
NORTHERN HALF OF OUR CWA. IF A CELL WERE TO DEVELOP ML CAPE VALUES
AROUND 2000 J/KG AND EFFECTIVE SHEAR VALUES AROUND 35KT COULD
SUPPORT A LIMITED SEVERE THREAT. IM JUST NOT SURE IF ANYTHING WILL
EVEN DEVELOP CONSIDERING THE DRY AIR MASS IN PLACE. I KEPT SLIGHT
CHANCE POPS IN THE AFTERNOON...COVERING POTENTIAL.
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 219 AM MDT TUE SEP 8 2015
BOTH THE GFS AND EUROPEAN HAVE A SIMILAR
UPPER LEVEL FLOW PATTERN WITH A TROUGH SITTING OVER THE EASTERN
PORTIONS OF THE US AND A RIDGE SITTING OVER THE WESTERN US. THIS
PATTERN STAYS CONSISTENT AND SIMILAR IN BOTH MODELS FRIDAY 12Z
THROUGH SATURDAY 18Z. AFTER THIS TIME THE GFS STARTS TO WEAKEN AND
BREAK UP THE EASTERN TROUGH...THIS CAUSES A CUT OFF LOW TO MOVE INTO
THE SOUTHEASTERN STATES. THE EUROPEAN SHOWS THIS TROUGH TO BE MUCH
STRONGER AND IT HOLDS STEADY AS IT CONTINUES TO MOVE EAST.
FOR SUNDAY INTO MONDAY THE GFS IS SHOWING A ZONAL FLOW PATTERN OVER
THE FAR NORTHERN STATES INTO CANADA WITH A CUT OFF LOW BREAKING OFF
AND MOVING INTO THE NORTHWESTERN STATES. THIS IS NOT THE SAME UPPER
LEVEL FLOW IN THE EUROPEAN. SINCE THE TROUGH IS MUCH STRONGER...THE
RIDGE IN THE WEST IS SHOWING TO BE A LITTLE STRONGER THAN IN THE
GFS. SO THE CUT OFF LOW IN THE NORTHWEST DOES NOT SHOW UP IN THE
EUROPEAN. THIS WILL BE SOMETHING TO KEEP AN EYE ON.
IN GENERAL...BOTH THE GFS AND EUROPEAN KEEP THE RIDGE IN THE WEST
STRONG...WHICH WILL START TO IMPACT THE REGION THIS WEEKEND. THIS
WILL CAUSE DRIER CONDITIONS AND TEMPERATURES WILL INCREASE SLIGHTLY
AS WE PROGRESS INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1122 AM MDT TUE SEP 8 2015
MVFR CIGS AROUND 1500 FT ARE STILL LIKELY TO ADVECT ACROSS THE
KMCK DURING THE EARLY PART OF THE TAF PERIOD WITH VIS SATELLITE
AND UPSTREAM OBS SHOWING THIS STRATUS FIELD MOVING SE WITH LOWEST
OBS BELOW 1000 FT. SHORT RANGE GUIDANCE INDICATES THIS SHOULD
CONTINUE TO DISSIPATE WITH DAYTIME HEATING...SO I WAS NOT
CONFIDENT ENOUGH TO CARRY MENTION OF MORE THAN TEMPO MVFR. VFR
WILL PREVAIL AT KGLD THROUGH THE FIRST 12 HR OF THE TAF PERIOD.
AFTER 06Z TONIGHT SOUTHERLY FLOW WILL BRING INCREASING
MOISTURE ONCE AGAIN TO THE REGION AND THE POSSIBILITY FOR
FOG/STRATUS. STRONGEST SIGNAL IN GUIDANCE IS IN SW NEBRASKA AND
SOUTH OF INTERSTATE 70...HOWEVER BOTH TERMINALS WILL LIKELY SEE A
PERIOD OF AT LEAST MVFR CONDITIONS AROUND SUNRISE. CONFIDENCE IS
TOO LOW TO INCLUDE LOWER CONDITIONS DUE TO A LACK OF
CONSENSUS/CONSISTENCY IN LOCATION OF BEST MOISTURE/LOWEST MIXING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...CLT
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1134 PM MDT MON SEP 7 2015
.UPDATE...
ISSUED AT 526 PM MDT MON SEP 7 2015
WITH MAIN AREA OF THUNDERSTORMS AHEAD OF FRONTAL ZONE TO THE SOUTH
OF THE AREA AND ATTEMPTS AT CONVECTION FADING ACROSS EXTREME
SOUTHWEST CWA HAVE REFINED POPS AND WX TO MORE CLOSELY FOLLOW
DEVELOPING LINE OF CONVECTION ACROSS NORTHEAST COLORADO ALONG
ROBUST COLD POOL. STARTING TO SEE SIGNIFICANT WIND GUSTS TO AROUND
45 MPH WITH THIS FEATURE AND THINK THAT WILL CONTINUE FOR NEXT 2
HOURS. WITH STRONGER CAP ACROSS THE EASTERN CWA NOT SURE HOW FAR
LINE WILL MAKE IT...SO HAVE BEEN SOMEWHAT PESSIMISTIC ABOUT
CHANCES ACROSS EASTERN HALF OF AREA.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 143 PM MDT MON SEP 7 2015
EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS SW
FLOW IN PLACE ACROSS CENTRAL ROCKIES OVER OUR CWA...AND INTO THE
NORTHERN PLAINS. THIS IS AHEAD OF LARGE UPPER LOW CENTERED OVER
CENTRAL CANADA WITH BROAD TROUGHING EXTENDING SOUTH ACROSS THE
PACIFIC NORTHWEST. CHECKING DYNAMIC TROPOPAUSE...EMBEDDED WEAK
SHORTWAVE TROUGH THAT ROTATED THROUGH REGION THIS MORNING IS NOW
OVER NORTHCENTRAL KS WITH A STRONGER PV HEIGHT ANOMALY ENTERING
CENTRAL COLORADO. SUBSIDENCE BEHIND THE INITIAL FEATURE IS STILL
TRANSITIONING ACROSS MOSTLY OF OUR CWA. AT THE SURFACE A STALLED
FRONT IS JUST SOUTH OF INTERSTATE 70 WITH SURFACE LOW EXTENDING
FROM SOUTHERN COLORADO ACROSS SW KS AND INTO NW KANSAS.
THIS AFTERNOON-TUESDAY...FORCING IS EXPECTED TO INCREASE THIS
EVENING WITH NEXT SHORTWAVE TROUGH MOVING OUT OF THE CENTRAL ROCKIES
AND INTERACTING WITH STALLED FRONTAL ZONE OVER OUR CWA. THERE IS
THE POSSIBILITY FOR OVERRUNNING/BACKBUILDING ALONG ELEVATED FRONTAL
ZONE/STRENGTHENING H7 TROUGH AXIS AS THIS FEATURE MOVES ACROSS THE
REGION. EAST/NORTHEAST FLOW WILL CONTINUE TO ADVECTS BOUNTIFUL
MOISTURE OVER OUR CWA...WITH MODERATE INSTABILITY CONTINUING
THROUGH THE EVENING. CONFIDENCE IS LOWER REGARDING COVERAGE...WITH
FAIRLY LARGE SPREAD IN GUIDANCE SINCE OVERNIGHT AND SUBSIDENCE
INITIALLY IN PLACE OVER OUR CWA. CURRENT ARW/NMM DEPICTS ACTIVITY
INITIATING WEST OF OUR CWA...OR OVER OUR WESTERN CWA AROUND 00Z AND
TRACKING ALONG/NORTH OF FRONT THIS EVENING/OVERNIGHT BEFORE SLOWLY
TRANSITIONING EAST. HRRR/RAP BOTH SUPPORT A SIMILAR LOCATION AND
TIMING...HOWEVER SHOW MUCH LESS IN THE WAY OF COVERAGE. I FELT
COMFORTABLE ADJUSTING THE TIMING TO FAVOR THIS EVENING FOR BEST
COVERAGE AND KEPT MENTION LIMITED TO CHANCE FOR NOW. GUIDANCE SHOWS
BAROCLINIC ZONE LINGERING THROUGH EARLY AFTERNOON TUESDAY ACROSS OUR
SOUTHEAST WITH ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT POSSIBLE.
I SHOWED GRADUAL TRANSITION TO THE EAST/SOUTHEAST IN LINE WITH
MODEL CONSENSUS.
REGARDING SEVERE THREAT...HIGH LOW LEVEL MIXING RATIOS HAVE AIDED IN
MODERATE INSTABILITY BUILDING ACROSS OUR CWA WITH ML CAPE 1500-2500
J/KG DEPICTED ON RAP ANALYSIS. DEEP UNIDIRECTIONAL FLOW HAS LED TO
HIGH SHEAR IN MID TO UPPER LEVELS WITH EFFECTIVE SHEER VALUES
ALREADY IN EXCESS OF 50KT OVER OUR CWA. BEST LOW LEVEL SHEAR IS
OVER NORTH CENTRAL KS/NEAR HILL CITY ASSOCIATED WITH VEERING NEAR
WHERE CLOSED SURFACE LOW MAY BE DEVELOPING BASED ON WIND/PRESSURE
FIELD. SEVERE THREAT SHOULD PREDOMINANTLY BE CONFINED TO LARGE
HAIL/DAMAGING WINDS...HOWEVER LOCATIONS IN THE FAR EASTERN PART OF
OUR CWA COULD SEE FAVORABLE CONDITIONS FOR SUPERCELL DEVELOPMENT
AND TORNADO RISK. WINDOW FOR THIS SHOULD BE CONFINED TO THIS
AFTERNOON/EARLY EVENING WITH FRONT TRANSITIONING BACK TO THE
SOUTHEAST THIS EVENING.
RAP/HRRR/NAM/SREF CONTINUE TO SHOW STRATUS/FOG REDEVELOPING ACROSS
NEBRASKA AND ADVECTING/SPREADING SOUTHWEST ACROSS OUR CWA. LOWEST
VIS COULD APPROACH DENSE FOG ADVISORY CRITERIA...THOUGH IT DOES
APPEAR TO BE FAIRLY TRANSIENT REGARDING LOWEST VISIBILITIES. FOR NOW
I KEPT AREAS OF FOG MENTION...AND WILL ALLOW SUBSEQUENT SHIFTS TO
MONITOR NEED FOR NEW DENSE FOG ADVISORY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 230 PM MDT MON SEP 7 2015
THE WESTERLY FLOW ALOFT ACROSS THE CENTRAL HIGH PLAINS TURNS NORTHWESTERLY
BY THURSDAY AND MORE NORTHERLY BY FRIDAY AND SATURDAY AS THE HIGH
PRESSURE AREA ALOFT OVER NORTHERN MEXICO RETROGRADES AND MERGES
WITH THE HIGH IN THE EASTERN PACIFIC TO FORM A RIDGE OVER THE
WESTERN UNITED STATES WHILE SHORT WAVES EMBEDDED IN THE UPPER
FLOW MOVE THROUGH THE CENTRAL HIGH PLAINS AND INTO THE BASE OF THE
TROUGH DEEPENING IN THE MISSISSIPPI VALLEY REGION. EXPECT ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS FROM WEDNESDAY NIGHT
THROUGH FRIDAY NIGHT AS A RESULT OF THESE DISTURBANCES MOVING
ACROSS THE REGION WITH THE SURFACE FRONTAL BOUNDARY REMAINING
STALLED IN THE VICINITY OF THE FORECAST AREA THROUGH THE END OF
THE WEEK. EXPECT DAYTIME HIGHS MAINLY IN THE 80S WITH LOWS MAINLY
IN THE 50S THROUGH THIS PERIOD.
SOMEWHAT COOLER TEMPERATURES ARE EXPECTED ON FRIDAY AND SATURDAY
WITH DRY CONDITIONS SATURDAY AND SUNDAY IN THE WAKE OF THE
STRONGER SHORT WAVE TROUGH ALOFT AND THE HIGH PRESSURE AREA TO
FOLLOW A COLD FRONT ACROSS THE REGION. SURFACE HIGH PRESSURE MOVES
OUT OF THE FORECAST ARE ON SUNDAY WITH THE LEE TROUGH DEVELOPING
AND TEMPERATURES WARMING AGAIN WITH SOUTHWEST SURFACE FLOW AND THE
WEAKENING RIDGE ALOFT OVER SOUTHWEST U.S. EXTENDING INTO THE
CENTRAL HIGH PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1130 PM MDT MON SEP 7 2015
ELEVATED THUNDERSTORMS STARTING TO DEVELOP IN RESPONSE TO NEARBY
UPPER LEVEL TROUGH...EXPECT SPOTTY COVERAGE NEAR TAF SITES AND
OVERALL AVIATION IMPACT TO BE LIMITED. OTHER CONCERN WILL BE
POTENTIAL FOR MORNING STRATUS...PRIMARILY AT MCK. LATEST MODELS
HAVE BACKED OFF OF COVERAGE AND CURRENT LIGHT VARIABLE WIND FIELD
NOT REALLY SHOWING A STRONG SIGN OF ADVECTION. HOWEVER...SAT FOG
PRODUCT SHOWING AN INCREASING AREA OF LOW CLOUDS AND THINK
REASONABLY HIGH THREAT FOR PERIOD OF IFR CIGS AT MCK. HAVE
DELAYED TIMING TILL CLOSER TO 12Z...BUT IF CIRRUS SHIELD WERE TO
THIN COULD SEE A QUICKER ONSET DUE TO STRONGER COOLING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1220 AM CDT TUE SEP 8 2015
.UPDATE...
ISSUED AT 636 PM CDT MON SEP 7 2015
The environment across the forecast area continues to evolve this
evening, and have adjusted the severe thunderstorm watch
accordingly. First off, northeast Kansas appears to have
stabilized substantially, and while there is a westerly advection
component of the more unstable central KS air, limited daytime
heating should keep the severe potential quite low in northeast
KS. Should note that ample shear remains in place, so any elevated
storms that can recognized this shear would pose a short lived
severe threat.
Central and east central KS remain quite unstable, with perhaps
the greatest instability into east central Kansas where Emporia
has a temperature of 88 with a dewpoint of 73 at last hour, likely
resulting in surface based CAPE well over 2000 J/Kg. Meanwhile,
effective shear at or greater than 40 kts has overspread the area.
This has fueled recent supercell development in Marion county and
could sustain the severe threat across the rest of east central KS
as well...although again the instability decreases into far
eastern KS. An outflow boundary near/just north of Emporia may
serve as a focus for severe storm development with very large
hail, damaging winds, and a small but non-zero threat for
tornadoes. Severe threat should wane after 9 PM.
&&
...Update to aviation forecast discussion...
.SHORT TERM...(THIS EVENING THROUGH Tuesday)
ISSUED AT 402 PM CDT MON SEP 7 2015
Showers and isolated storms continued off and on through the
afternoon hours in a zone of 1000-900mb convergence, weak isentropic
lift and the presence of a weak wave. Although the bulk of the
precipitation has moved east into missouri expect isolated to
scattered showers to continue across east central Kansas into the
early evening hours. Further north near the Nebraska border where
few clouds have allowed temperatures to warm into the lower to mid
90s. Latest mesoanalysis shows about 40 to 50kts of effective
shear, 1500-3000 J/kg of CAPE and no cap in place. Isolated
thunderstorms have developed just to the northwest of the forecast
area and were moving northeast across southern Nebraska at 1930Z.
Latest runs of the HRRR and the RAP suggest further development
across north central Kansas into the evening hours, with
additional development from central Kansas across northeast Kansas
through the evening hours. Storms that can develop across the
northern counties may be severe with hail, strong winds and an
isolated tornado possible. Another round of storms is expected
overnight into Tuesday morning as the upper level trough
progresses eastward across the Northern and Central Plains. Good
moisture transport is expected into northeast Kansas overnight
with precipitable water around 2 inches which will increase the
potential for locally heavy rainfall. The front is expected to
move slowly southeast across the forecast area on Tuesday then
moving out of east central Kansas Tuesday evening. Showers and
thunderstorms will likely be ongoing in the morning hours and then
continue along the boundary in the afternoon.
Clouds south of I-70 have kept temperatures in check in the upper
70s to upper 80s. Will likely still see some fluctuations in
temperatures through the late afternoon where the sun can come out.
Tonight, lows should cool into the low to mid 70s with highs on
Tuesday only in the low to mid 80s.
.LONG TERM...(Tuesday NIGHT THROUGH Monday)
ISSUED AT 402 PM CDT MON SEP 7 2015
Cold front and associated showers and thunderstorms should be
moving to the southeast out of east central KS Tuesday evening.
Then surface high pressure builds in with pleasant temperatures
and lower humidities for Wednesday and Wednesday night.
Northwest flow aloft then sets up through the end of the week
with the first in a series of disturbances possibly affecting
north central KS by late Thursday afternoon. That system moves
through Thursday night through Friday with a good chance of
thunderstorms during this time.
Subsidence behind the trough and associated surface high pressure
builds in for Saturday, and an upper ridge builds eastward for
Sunday and Monday, keeping the weekend into Monday dry.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Tuesday NIGHT)
ISSUED AT 1219 AM CDT TUE SEP 8 2015
Will keep vcts through the overnight hours as showers/storms still
popping up occasionally. Added a tempo for best timing of storms
to form along the front as it moves through the terminals late
morning. May have mvfr cigs behind the boundary but at this time
is advertised to clear out rather fast with the wind shift.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...53
LONG TERM...GDP
AVIATION...67
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
957 PM EDT WED SEP 9 2015
...FORECAST UPDATE...
ISSUED AT 955 PM EDT WED SEP 9 2015
SURFACE COLD FRONT AT 01Z WAS DRAPED ROUGHLY E-W OR NE-SW ACROSS
CENTRAL KY, ALTHOUGH EXACT POSITION A BIT DIFFICULT TO TELL, LIKELY
NEAR AN AXIS OF NEAR CALM WIND FROM LEX TO BWG. THERE ALSO APPEARED
TO BE A WEAK AREA OF LOW PRESSURE ROUGHLY NEAR THE SW KY/NW TN
BORDER ALONG THE BOUNDARY. AHEAD OF THIS LOW, RADAR SHOWED AN AREA
OF RAIN AND EMBEDDED STORMS OVER CENTRAL KY, ESPECIALLY BUTLER,
GRAYSON, AND EDMONSON COUNTIES AT 0145Z. IN FACT, RADAR LOOP
SUGGESTS A BROAD CIRCULATION ASSOCIATED WITH THE AREA OF RAIN.
EXPECT THE RAIN AND EMBEDDED CONVECTION TO PUSH ENE LATE THIS
EVENING INTO THE OVERNIGHT PERIOD WITH THE MESOSCALE SHORTWAVE
PROVIDING FORCING FOR LIFT. OCCASIONAL HEAVY RAIN MAY CONTINUE
ASSOCIATED WITH THIS FEATURE.
ELSEWHERE, WITH A BROAD SW-NE-ORIENTED MID-UPPER LEVEL MOISTURE
PLUME OVER THE OH AND TN VALLEYS AS SHOWN IN WATER VAPOR IMAGERY,
AND WITH THE WEAK SURFACE BOUNDARY/LOW IN THE VICINITY, SCATTERED
SHOWERS ARE EXPECTED OVER MUCH OF THE REMAINDER OF CENTRAL KY
OVERNIGHT, WITH THE BEST COVERAGE OVER SOUTHERN/EASTERN COUNTIES.
THERE SHOULD BE LITTLE PRECIP OVER MOST OF SOUTH-CENTRAL IN.
LATEST DATA SUGGESTS FOG MAY NOT BE AS MUCH OF A PROBLEM TOWARD
MORNING AS EARLIER EXPECTED, BUT STILL AREAS OF FOG AND LOWER CLOUDS
ARE EXPECTED AND RETAINED IN THE FORECAST. NO SIGNIFICANT CHANGES TO
TEMPS NEEDED OVERNIGHT FROM ONGOING FORECAST.
.SHORT TERM (NOW THROUGH THURSDAY NIGHT)...
ISSUED AT 245 PM EDT WED SEP 9 2015
AS OF MID AFTERNOON...WATER VAPOR IMAGERY AND 500 MB HEIGHTS SHOWED
A SHORTWAVE TROUGH EXTENDING FROM THE GREAT LAKES DOWN ALONG THE
MISSISSIPPI RIVER...JUST WEST OF CENTRAL KENTUCKY. AT THE
SURFACE...THE ENVIORNMENT IS CHARACTERIZED BY WARM AND MOIST AIR
WITH DEWPOINTS IN THE LOW 70S. A COLD FRONT LIED ALONG THE OHIO
RIVER...SLOWLY MOVING EAST THROUGH THE AREA.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY IN THE WARM
SECTOR WILL CONTINUE THROUGH THE LATE AFTERNOON HOURS. THESE STORMS
WILL BE CAPABLE OF PROUDCING BRIEF BUT VERY HEAVY RAINFALL GIVEN THE
HIGH PWATS IN THE AREA. SOME GUSTY WINDS ARE POSSIBLE AS WELL.
HI-RES MODELS SUCH AS THE HRRR AND 12Z SPC WRF ARE IN GOOD AGREEMENT
SHOWING THE HIGHEST CHANCES NOW THROUGH EARLY EVENING...THEN A
DECREASE IN COVERAGE AS THE UPPER SHORTWAVE TROUGH KICKS THE FRONT
EAST THROUGH THE AREA. A SECONDARY LOW PRESSURE AND TROUGH NEAR
MEMPHIS WILL TRACK THROUGH CENTRAL TN TO SOUTHEAST KY OVERNIGHT...
KEEPING SOME SHOWERS AND STORMS IN THE FORECAST MAINLY OVERNIGHT
FOR THE SOUTHERN FORECAST AREA. AREAS NORTH OF THE KY PARKWAYS
INTO SOUTHERN INDIANA WILL PROBABLY SEE THE END OF THE RAIN FROM
THIS SYSTEM THIS EVENING OR EARLY OVERNIGHT.
LOW CLOUDS AND/OR FOG IS A CONCERN OVERNIGHT INTO THE THURSDAY
MORNING COMMUTE AS THE BOUNDARY LAYER WILL REMAIN VERY MOIST WITH
LIGHT WINDS. SREF PROBABIALITIES FOR LOW CLOUDS /500 FT OR LESS/ AND
FOG ARE BETWEEN 40 AND 60 PERCENT. WILL HAVE TO WATCH FOR LOCALLY
DENSE POCKETS OF FOG...ESPECIALLY IF THERE IS ANY CLEARING OR BREAKS
IN THE CLOUDS TOWARD SUNRISE.
IMPROVING CONDITIONS CAN BE EXPECTED DURING THE DAY THURSDAY. SOME
LINGERING SHOWERS AND MAYBE A THUNDERSTORM WILL BE POSSIBLE ALONG
AND SOUTHEAST OF A LEXINGTON TO BOWLNG GREEN LINE DURING THE MORNING
BUT THIS SHOULD QUICKLY MOVE EAST BY NOON. NORTHWEST WINDS WILL PICK
UP...HELPING TO SCATTER OUT OR LIFT SOME OF THE CLOUDS IN THE
AREA. LOOK FOR HIGHS RIGHT AROUND NORMAL IN THE LOW 80S.
.LONG TERM (FRIDAY THROUGH WEDNESDAY)...
ISSUED AT 305 PM EDT WED SEP 9 2015
THE LONG TERM PERIOD WILL START OUT WITH A COLD FRONT PASSAGE ON
FRIDAY BRINGING SHOWERS/STORMS TO THE AREA FRI/FRI NIGHT. ALTHOUGH
THE OVERALL FORCING NEAR THE FRONT AND WIND SHEAR LOOK RELATIVELY
WEAK, THERE MAY BE ENOUGH SFC INSTABILITY TO PRODUCE A FEW STRONG
CELLS DURING THE AFTERNOON HOURS FRIDAY. OVERALL THOUGH, DON`T SEE
A BIG THREAT FOR ORGANIZED STRONG TO SEVERE CONVECTION FOR FRIDAY.
THE BIGGER STORY WITH THIS FRONT WILL BE THE STRONG UPPER LOW AND
MUCH COOLER AIRMASS FOLLOWING IT. WITH THESE FEATURES IN PLACE FOR
THE WEEKEND, LOOK FOR TEMPS TO BE 6 TO 12 DEGREES BELOW NORMAL.
SATURDAY WE`LL HAVE PLENTY OF LOW CLOUDS AND LINGERING SHOWERS
LIMITING HIGHS TO THE MID TO UPPER 60S. SOME MODEL DATA SUGGESTS
PERHAPS WE COULD SEE AN ISLD RUMBLE OF THUNDER WITH THIN, SHALLOW
INSTABILITY PRESENT IN THE SOUNDINGS. SHOWER ACTIVITY SHOULD
CONTINUE INTO SAT NIGHT BEFORE GRADUALLY ENDING FROM WEST TO EAST
SUN MORNING. HIGHS ON SUNDAY WILL BE SIMILAR TO SAT IN THE MID TO
UPPER 60S. LOW TEMPERATURES THIS WEEKEND WILL RANGE FROM THE MID
40S TO LOWER 50S WITH THE COOLEST NIGHT BEING SUN NIGHT INTO MONDAY
MORNING WHEN SKIES WILL BECOME CLEAR WITH THE HIGH PRESSURE CENTER
OVER THE REGION.
WE`LL REMAIN DRY MON-WED WITH RETURN FLOW BRINGING WARMER TEMPS BACK
INTO THE REGION. HIGHS ON MONDAY WILL WARM BACK INTO THE LOWER 70S
WITH UPPER 70S/LOWER 80S EXPECTED BY TUES/WED UNDER MOSTLY SUNNY
SKIES.
&&
.AVIATION (00Z TAF UPDATE)...
ISSUED AT 730 PM EDT WED SEP 9 2015
SURFACE FRONT LIES ACROSS CENTRAL KY AT 23Z WITH SHOWERS AND
SCATTERED THUNDERSTORMS ALONG AND SOUTH OF IT, AND SCATTERED LIGHT
SHOWERS TO ITS NORTH. FOR THE NEXT FEW HOURS, BWG WILL BE AFFECTED
MOST WITH SHOWERS AND A FEW HEAVY RAIN PRODUCING STORMS REDUCING
VSBYS INTO MVFR CATEGORY, WITH SOME SHOWERS CONTINUING THEREAFTER.
SHOWERS WILL BE MORE SCATTERED AT LEX AND SDF. MVFR CEILINGS AT LEX
AT 23Z MAY SCATTER OUT FOR A TIME THIS EVENING WITH VFR CONTINUING
AT SDF.
OVERNIGHT...CLOUDS AND SCATTERED TO NUMEROUS SHOWERS WILL CONTINUE
NEAR THE MEANDERING FRONT. CEILINGS AND VSBYS SHOULD LOWER OVERNIGHT
INTO AT LEAST MVFR AND POSSIBLY IFR CATEGORY BEGINNING BEFORE
DAYBREAK (ROUGHLY 08-10Z), ESPECIALLY AT LEX AND BWG. CONDITIONS ARE
EXPECTED TO IMPROVE QUICKLY AFTER 13 OR 14Z WITH LOW CLOUDS
SCATTERING OUT AND VSBYS BECOMING P6SM BY LATE MORNING.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.........TWF
SHORT TERM.....ZBT
LONG TERM......AMS
AVIATION.......TWF
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
738 PM EDT WED SEP 9 2015
...UPDATED AVIATION DISCUSSION...
.SHORT TERM (NOW THROUGH THURSDAY NIGHT)...
ISSUED AT 245 PM EDT WED SEP 9 2015
AS OF MID AFTERNOON...WATER VAPOR IMAGERY AND 500 MB HEIGHTS SHOWED
A SHORTWAVE TROUGH EXTENDING FROM THE GREAT LAKES DOWN ALONG THE
MISSISSIPPI RIVER...JUST WEST OF CENTRAL KENTUCKY. AT THE SURFACE...
THE ENVIORNMENT IS CHARACTERIZED BY WARM AND MOIST AIR WITH
DEWPOINTS IN THE LOW 70S. A COLD FRONT LIED ALONG THE OHIO
RIVER...SLOWLY MOVING EAST THROUGH THE AREA.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY IN THE WARM
SECTOR WILL CONTINUE THROUGH THE LATE AFTERNOON HOURS. THESE STORMS
WILL BE CAPABLE OF PROUDCING BRIEF BUT VERY HEAVY RAINFALL GIVEN THE
HIGH PWATS IN THE AREA. SOME GUSTY WINDS ARE POSSIBLE AS WELL.
HI-RES MODELS SUCH AS THE HRRR AND 12Z SPC WRF ARE IN GOOD AGREEMENT
SHOWING THE HIGHEST CHANCES NOW THROUGH EARLY EVENING...THEN A
DECREASE IN COVERAGE AS THE UPPER SHORTWAVE TROUGH KICKS THE FRONT
EAST THROUGH THE AREA. A SECONDARY LOW PRESSURE AND TROUGH NEAR
MEMPHIS WILL TRACK THROUGH CENTRAL TN TO SOUTHEAST KY OVERNIGHT...
KEEPING SOME SHOWERS AND STORMS IN THE FORECAST MAINLY OVERNIGHT
FOR THE SOUTHERN FORECAST AREA. AREAS NORTH OF THE KY PARKWAYS
INTO SOUTHERN INDIANA WILL PROBABLY SEE THE END OF THE RAIN FROM
THIS SYSTEM THIS EVENING OR EARLY OVERNIGHT.
LOW CLOUDS AND/OR FOG IS A CONCERN OVERNIGHT INTO THE THURSDAY
MORNING COMMUTE AS THE BOUNDARY LAYER WILL REMAIN VERY MOIST WITH
LIGHT WINDS. SREF PROBABIALITIES FOR LOW CLOUDS /500 FT OR LESS/ AND
FOG ARE BETWEEN 40 AND 60 PERCENT. WILL HAVE TO WATCH FOR LOCALLY
DENSE POCKETS OF FOG...ESPECIALLY IF THERE IS ANY CLEARING OR BREAKS
IN THE CLOUDS TOWARD SUNRISE.
IMPROVING CONDITIONS CAN BE EXPECTED DURING THE DAY THURSDAY. SOME
LINGERING SHOWERS AND MAYBE A THUNDERSTORM WILL BE POSSIBLE ALONG
AND SOUTHEAST OF A LEXINGTON TO BOWLNG GREEN LINE DURING THE MORNING
BUT THIS SHOULD QUICKLY MOVE EAST BY NOON. NORTHWEST WINDS WILL PICK
UP...HELPING TO SCATTER OUT OR LIFT SOME OF THE CLOUDS IN THE
AREA. LOOK FOR HIGHS RIGHT AROUND NORMAL IN THE LOW 80S.
.LONG TERM (FRIDAY THROUGH WEDNESDAY)...
ISSUED AT 305 PM EDT WED SEP 9 2015
THE LONG TERM PERIOD WILL START OUT WITH A COLD FRONT PASSAGE ON
FRIDAY BRINGING SHOWERS/STORMS TO THE AREA FRI/FRI NIGHT. ALTHOUGH
THE OVERALL FORCING NEAR THE FRONT AND WIND SHEAR LOOK RELATIVELY
WEAK, THERE MAY BE ENOUGH SFC INSTABILITY TO PRODUCE A FEW STRONG
CELLS DURING THE AFTERNOON HOURS FRIDAY. OVERALL THOUGH, DON`T SEE
A BIG THREAT FOR ORGANIZED STRONG TO SEVERE CONVECTION FOR FRIDAY.
THE BIGGER STORY WITH THIS FRONT WILL BE THE STRONG UPPER LOW AND
MUCH COOLER AIRMASS FOLLOWING IT. WITH THESE FEATURES IN PLACE FOR
THE WEEKEND, LOOK FOR TEMPS TO BE 6 TO 12 DEGREES BELOW NORMAL.
SATURDAY WE`LL HAVE PLENTY OF LOW CLOUDS AND LINGERING SHOWERS
LIMITING HIGHS TO THE MID TO UPPER 60S. SOME MODEL DATA SUGGESTS
PERHAPS WE COULD SEE AN ISLD RUMBLE OF THUNDER WITH THIN, SHALLOW
INSTABILITY PRESENT IN THE SOUNDINGS. SHOWER ACTIVITY SHOULD
CONTINUE INTO SAT NIGHT BEFORE GRADUALLY ENDING FROM WEST TO EAST
SUN MORNING. HIGHS ON SUNDAY WILL BE SIMILAR TO SAT IN THE MID TO
UPPER 60S. LOW TEMPERATURES THIS WEEKEND WILL RANGE FROM THE MID
40S TO LOWER 50S WITH THE COOLEST NIGHT BEING SUN NIGHT INTO MONDAY
MORNING WHEN SKIES WILL BECOME CLEAR WITH THE HIGH PRESSURE CENTER
OVER THE REGION.
WE`LL REMAIN DRY MON-WED WITH RETURN FLOW BRINGING WARMER TEMPS BACK
INTO THE REGION. HIGHS ON MONDAY WILL WARM BACK INTO THE LOWER 70S
WITH UPPER 70S/LOWER 80S EXPECTED BY TUES/WED UNDER MOSTLY SUNNY
SKIES.
&&
.AVIATION (00Z TAF UPDATE)...
ISSUED AT 730 PM EDT WED SEP 9 2015
SURFACE FRONT LIES ACROSS CENTRAL KY AT 23Z WITH SHOWERS AND
SCATTERED THUNDERSTORMS ALONG AND SOUTH OF IT, AND SCATTERED LIGHT
SHOWERS TO ITS NORTH. FOR THE NEXT FEW HOURS, BWG WILL BE AFFECTED
MOST WITH SHOWERS AND A FEW HEAVY RAIN PRODUCING STORMS REDUCING
VSBYS INTO MVFR CATEGORY, WITH SOME SHOWERS CONTINUING THEREAFTER.
SHOWERS WILL BE MORE SCATTERED AT LEX AND SDF. MVFR CEILINGS AT LEX
AT 23Z MAY SCATTER OUT FOR A TIME THIS EVENING WITH VFR CONTINUING
AT SDF.
OVERNIGHT...CLOUDS AND SCATTERED TO NUMEROUS SHOWERS WILL CONTINUE
NEAR THE MEANDERING FRONT. CEILINGS AND VSBYS SHOULD LOWER OVERNIGHT
INTO AT LEAST MVFR AND POSSIBLY IFR CATEGORY BEGINNING BEFORE
DAYBREAK (ROUGHLY 08-10Z), ESPECIALLY AT LEX AND BWG. CONDITIONS ARE
EXPECTED TO IMPROVE QUICKLY AFTER 13 OR 14Z WITH LOW CLOUDS
SCATTERING OUT AND VSBYS BECOMING P6SM BY LATE MORNING.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
SHORT TERM........ZBT
LONG TERM.........AMS
AVIATION..........TWF
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
237 PM EDT TUE SEP 8 2015
.SYNOPSIS...
RAIN WILL BE LIKELY AS A COLD FRONT APPROACHES ON WEDNESDAY AND
SLOWLY MOVES THROUGH THE AREA ON THURSDAY. THIS WILL BRING TO AN
END OUR PERIOD OF MUCH ABOVE NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
CUMULUS HAS BEEN DEVELOPING RATHER READILY JUST TO THE NORTH AND
WEST OF THE FORECAST AREA WHERE BOUNDARY LAYER MOISTURE IS
DECIDEDLY HIGHER. THIS IS EVIDENCED BY DEWPOINTS ACROSS WESTERN
AND NORTHERN OHIO NOW RUNNING UP TOWARD AND EVEN ABOVE 70F IN SOME
CASES. AS YOU MOVE EASTWARD TOWARD THE OHIO RIVER AND IN WESTERN
PENNSYLVANIA...LOWER TO MID 60 DEWPOINTS ARE MORE COMMON. A
DISTRIBUTION SIMILAR TO THIS HAS BEEN INDICATED BY THE
HRRR...HOWEVER THE NORMAL OVERLY AGGRESSIVE DRY AIR ENTRAINMENT OF
THE HRRR IS ALSO NOTED...SO WHILE THE DISTRIBUTION OF DEWPOINT
VALUES IS REPRESENTATIVE...THE VALUES FAIL TO BE ACCURATE. THE
LOWERING OF BOUNDARY LAYER MOISTURE OVER PENNSYLVANIA HAS MANAGED
TO ALLOW FOR SLOWER CUMULUS GROWTH...AND THE DRY AIR ALOFT SHOULD
PRECLUDE SHOWER DEVELOPMENT...EVEN WITH AMPLE INSOLATION THROUGH
THE EVENING. THAT SAID...VERY WARM CONDITIONS WILL REMAIN OVER THE
FORECAST AREA WITH WARM ADVECTION CONTINUING INTO TONIGHT AS 850
MB TEMPERATURES RUN UP TOWARD +19C TODAY WITH AT LEAST MODEST
MIXING.
GLOBAL MODEL AND ENSEMBLE SOLUTIONS CONTINUE TO BE FAIRLY SLOW
WITH THE LARGE SCALE EVOLUTION OF THE NEXT SYSTEM THAT WILL IMPACT
THE AREA BEGINNING ON WEDNESDAY. LAYER RH PLOTS REVEAL MUCH OF THE
NIGHT SHOULD REMAIN RATHER CLEAR AFTER WE DECOUPLE THIS EVENING.
THIS WILL AGAIN ALLOW FOR A BIT OF RIVER VALLEY FOG...HOWEVER ITS
EXPANSION AWAY FROM RIVERS SEEMS RATHER UNLIKELY...SO IT WAS NOT
CARRIED IN THE GRIDS. ADDITIONALLY...WITH LITTLE CHANGE IN THE
OVERALL PATTERN FOR TONIGHT RELATIVE TO RECENT NIGHTS...LOW
TEMPERATURES NEAR PERSISTENCE SEEM REASONABLE.
FINALLY ON WEDNESDAY LAYER RH VALUES START TO KICK UPWARD...AS THE
MID-LEVEL FRONTAL BOUNDARY STARTS TO TRUCK EASTWARD OUT OF THE
CENTRAL GREAT LAKES AND TOWARD THE UPPER OHIO VALLEY. INSTABILITY
AHEAD OF THE FRONT IS NOT OVERLY IMPRESSIVE AS NO MODEL EVEN
ECLIPSES 1000 J/KG OF CAPE AND SHEAR IS LIKEWISE MEAGER...SO WHILE
SOME THUNDER DEVELOPMENT IS LIKELY...ORGANIZED SEVERE WEATHER IS
NOT. THAT SAID...DIFFERENTIAL PVA ALONG SAID FRONT OUT AHEAD OF
THE RIGHT ENTRANCE REGION OF THE UPPER JET SHOULD GIVE ENOUGH OF A
SYNOPTIC SCALE KICK TO ALLOW FOR THOSE <1000 J/KG TO BE REALIZED.
AS A RESULT...POPS WERE CONTINUED AS LIKELY THROUGH THE AFTERNOON
HOURS. HOWEVER...BEFORE PRECIPITATION ENVELOPS THE
AREA...TEMPERATURES SHOULD GET A NICE KICK NORTHWARD WITH ANOTHER
DAY OF SOLIDLY ABOVE NORMAL TEMPERATURES BEFORE THE FRONTAL
ARRIVAL. FRIES
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
THE WEAKENING FRONTAL BOUNDARY WILL LOSE ITS FORWARD PROGRESS AS
IT REACHES THE FORECAST AREA OVERNIGHT WEDNESDAY AND EARLY
THURSDAY. THIS WILL ALLOW A SHORTWAVE TO RIDE NORTHWARD ALONG THE
FRONT THURSDAY MORNING...WITH HINTS TO THIS DEVELOPMENT ON ALL OF
THE LATEST MODEL GUIDANCE. THUS...FORECAST WAS UPDATED TO CARRY
LIKELY POPS THROUGH THE FIRST HALF OF THURSDAY BEFORE THE WAVE AND
BOUNDARY PUSH EASTWARD. CONSIDERING THE OVERNIGHT TIMING FOR THE
FRONT...WILL MENTION THE CHANCE FOR THUNDER...BUT INSTABILITY IS
RATHER NEGLIGIBLE. TEMPERATURES SHOULD BEGIN TO FALL BACK TOWARD
SEASONAL VALUES ONCE THIS FRONT HAS PASSED...BUT THE NOTICEABLY
COOLER AIR WILL NOT MAKE IT UNTIL THE SECONDARY FRONT AND
DEEPENING UPPER TROUGH APPROACHES FOR THE WEEKEND.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
BROAD UPPER LEVEL TROUGHING IS FORECAST TO DEVELOP OVER THE EASTERN
CONUS FOR THE LONG TERM PERIOD...LEADING TO COOLER TEMPERATURES AND
LOW PRECIP CHANCES. EXTENDED GRIDS WERE CONSTRUCTED CLOSE TO WPC
GUIDANCE.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
VFR CONDITIONS ARE LIKELY TO CONTINUE THROUGH THE AFTERNOON AND
INTO THE MAJORITY OF THE OVERNIGHT WITH LIGHT SOUTHWESTERLY WINDS
BECOMING CALM. CLOUDS WILL INCREASE FROM W-E ON WEDNESDAY MORNING
IN ADVANCE OF THE NEXT SYSTEM TO CROSS THE AREA. SHOWERS AND
THUNDERSTORMS WILL BECOMING LIKELY BY AFTERNOON...LIKELY CAUSING
LOCAL RESTRICTIONS JUST AFTER THE END OF THE TAF VALID PERIOD.
FRIES
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
RESTRICTIONS WILL BECOME LIKELY WITH THE APPROACH OF A COLD FRONT
ON WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
139 PM EDT TUE SEP 8 2015
.SYNOPSIS...
RAIN WILL BE LIKELY AS A COLD FRONT APPROACHES ON WEDNESDAY AND
SLOWLY MOVES THROUGH THE AREA ON THURSDAY. THIS WILL BRING TO AN
END OUR PERIOD OF MUCH ABOVE NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
CUMULUS HAS BEEN DEVELOPING RATHER READILY JUST TO THE NORTH AND
WEST OF THE FORECAST AREA WHERE BOUNDARY LAYER MOISTURE IS
DECIDEDLY HIGHER. THIS IS EVIDENCED BY DEWPOINTS ACROSS WESTERN
AND NORTHERN OHIO NOW RUNNING UP TOWARD AND EVEN ABOVE 70F IN SOME
CASES. AS YOU MOVE EASTWARD TOWARD THE OHIO RIVER AND IN WESTERN
PENNSYLVANIA...LOWER TO MID 60 DEWPOINTS ARE MORE COMMON. A
DISTRIBUTION SIMILAR TO THIS HAS BEEN INDICATED BY THE
HRRR...HOWEVER THE NORMAL OVERLY AGGRESSIVE DRY AIR ENTRAINMENT OF
THE HRRR IS ALSO NOTED...SO WHILE THE DISTRIBUTION OF DEWPOINT
VALUES IS REPRESENTATIVE...THE VALUES FAIL TO BE ACCURATE. THE
LOWERING OF BOUNDARY LAYER MOISTURE OVER PENNSYLVANIA HAS MANAGED
TO ALLOW FOR SLOWER CUMULUS GROWTH...AND THE DRY AIR ALOFT SHOULD
PRECLUDE SHOWER DEVELOPMENT...EVEN WITH AMPLE INSOLATION THROUGH
THE EVENING. THAT SAID...VERY WARM CONDITIONS WILL REMAIN OVER THE
FORECAST AREA WITH WARM ADVECTION CONTINUING INTO TONIGHT AS 850
MB TEMPERATURES RUN UP TOWARD +19C TODAY WITH AT LEAST MODEST
MIXING.
GLOBAL MODEL AND ENSEMBLE SOLUTIONS CONTINUE TO BE FAIRLY SLOW
WITH THE LARGE SCALE EVOLUTION OF THE NEXT SYSTEM THAT WILL IMPACT
THE AREA BEGINNING ON WEDNESDAY. LAYER RH PLOTS REVEAL MUCH OF THE
NIGHT SHOULD REMAIN RATHER CLEAR AFTER WE DECOUPLE THIS EVENING.
THIS WILL AGAIN ALLOW FOR A BIT OF RIVER VALLEY FOG...HOWEVER ITS
EXPANSION AWAY FROM RIVERS SEEMS RATHER UNLIKELY...SO IT WAS NOT
CARRIED IN THE GRIDS. ADDITIONALLY...WITH LITTLE CHANGE IN THE
OVERALL PATTERN FOR TONIGHT RELATIVE TO RECENT NIGHTS...LOW
TEMPERATURES NEAR PERSISTENCE SEEM REASONABLE.
FINALLY ON WEDNESDAY LAYER RH VALUES START TO KICK UPWARD...AS THE
MID-LEVEL FRONTAL BOUNDARY STARTS TO TRUCK EASTWARD OUT OF THE
CENTRAL GREAT LAKES AND TOWARD THE UPPER OHIO VALLEY. INSTABILITY
AHEAD OF THE FRONT IS NOT OVERLY IMPRESSIVE AS NO MODEL EVEN
ECLIPSES 1000 J/KG OF CAPE AND SHEAR IS LIKEWISE MEAGER...SO WHILE
SOME THUNDER DEVELOPMENT IS LIKELY...ORGANIZED SEVERE WEATHER IS
NOT. THAT SAID...DIFFERENTIAL PVA ALONG SAID FRONT OUT AHEAD OF
THE RIGHT ENTRANCE REGION OF THE UPPER JET SHOULD GIVE ENOUGH OF A
SYNOPTIC SCALE KICK TO ALLOW FOR THOSE <1000 J/KG TO BE REALIZED.
AS A RESULT...POPS WERE CONTINUED AS LIKELY THROUGH THE AFTERNOON
HOURS. HOWEVER...BEFORE PRECIPITATION ENVELOPS THE
AREA...TEMPERATURES SHOULD GET A NICE KICK NORTHWARD WITH ANOTHER
DAY OF SOLIDLY ABOVE NORMAL TEMPERATURES BEFORE THE FRONTAL
ARRIVAL. FRIES
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
A WEAKENING WIND FIELD IN THE WAKE OF AN EXITING JET
STREAK...WHICH IS PROGGED TO TAIL OFF ACROSS THE WESTERN GREAT
LAKES...SHOULD...ALONG WITH POTENTIAL SHORTWAVE PROGRESSION ALONG
THE FRONT...LIMIT DECISIVE PASSAGE UNTIL THURSDAY.
NEVERTHELESS...WITH WEAKENING UPPER SUPPORT AND FADING
INSTABILITY...HAVE TAPERED POPS DOWNWARD ON WEDNESDAY NIGHT...AND
CONTINUED THE TREND THROUGH THURSDAY AS PER A SPLIT OF GFS AND NAM
DEPICTIONS OF FRONTAL AND MID LEVEL TROUGH PROGRESS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
BROAD UPPER LEVEL TROUGHING IS FORECAST TO DEVELOP OVER THE EASTERN
CONUS FOR THE LONG TERM PERIOD...LEADING TO COOLER TEMPERATURES AND
LOW PRECIP CHANCES. EXTENDED GRIDS WERE CONSTRUCTED CLOSE TO WPC
GUIDANCE.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
VFR CONDITIONS ARE LIKELY TO CONTINUE THROUGH THE AFTERNOON AND
INTO THE MAJORITY OF THE OVERNIGHT WITH LIGHT SOUTHWESTERLY WINDS
BECOMING CALM. CLOUDS WILL INCREASE FROM W-E ON WEDNESDAY MORNING
IN ADVANCE OF THE NEXT SYSTEM TO CROSS THE AREA. SHOWERS AND
THUNDERSTORMS WILL BECOMING LIKELY BY AFTERNOON...LIKELY CAUSING
LOCAL RESTRICTIONS JUST AFTER THE END OF THE TAF VALID PERIOD.
FRIES
OUTLOOK...WEDNESDAY THROUGH SATURDAY... RESTRICTIONS
WILL BECOME LIKELY WITH THE APPROACH OF A COLD FRONT ON WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
418 PM EDT TUE SEP 8 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 417 PM EDT TUE SEP 8 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A MID/UPPER LEVEL LOW
SPINNING OVER MANITOBA. ONE SHORTWAVE IS LIFTING NE ACROSS NRN
ONTARIO TO THE N OF LAKE OF THE WOODS. TAIL END OF THAT WAVE IS
GENERATING SHRA/TSRA N OF THE MN/ONTARIO BORDER. CLOSER TO HOME...
SHORTWAVE THAT LIFTED ACROSS WI TOWARD ERN UPPER MI BROUGHT
WIDESPREAD SHRA/ISOLD TSTMS ACROSS ALL BUT FAR WRN UPPER MI TODAY.
THAT ACTIVITY IS MOVING OUT QUICKLY NOW. TO THE W...IT APPEARS THAT
THERE ARE 2 BOUNDARIES THAT STILL NEED TO BE WATCHED FOR NEW
CONVECTIVE DEVELOPMENT. THE FIRST IS LAKE BREEZE BOUNDARY RUNNING
FROM THE E SIDE OF THE KEWEENAW TO CNTRL GOGEBIC COUNTY...AND THE
OTHER IS THE COLD FRONT MOVING ACROSS THE WRN PART OF LAKE SUPERIOR.
MOSTLY FOLLOWED RECENT RADAR TRENDS TO MOVE LINGERING WIDESPREAD
SHRA OUT OF THE ERN FCST AREA OVER THE NEXT FEW HRS. HELD LOW POPS
BACK TO THE W AHEAD OF THE TWO AFOREMENTIONED BOUNDARIES. LATEST SPC
MESOANALYSIS HAS MLCAPES UP TO AROUND 250J/KG OR SO AND SBCAPE TO
AROUND 500J/KG AHEAD OF THE BOUNDARIES. WITH CU BUILDING UP PER VIS
SATELLITE IMAGERY...CAN`T RULE OUT ISOLD/SCT SHRA DEVELOPMENT...
PERHAPS A TSTM. WHATEVER HAPPENS...PCPN RISK WILL BE DONE BY LATE
EVENING AS COLD FRONT SWEEPS ACROSS THE AREA. MUCH DRIER AIR MASS
SURGING INTO THE AREA WILL FINALLY BRING AN END TO THE UNSEASONABLY
LONG STRETCH OF HIGH DWPTS FOR THIS TIME OF YEAR. UPSTREAM IN NRN
MN...SFC DWPTS HAVE FALLEN THRU THE 40S WITH EVEN SOME 30S SHOWING
UP. EXPECT CLEARING SKIES FROM THE W TONIGHT. IF THERE IS ANY FOG ON
LAKE SUPERIOR...IT WILL AFFECT THE ERN SHORELINE AREAS BEFORE BEING
SWEPT CLEAR BY THE MUCH DRIER AIR MASS. IT WILL BE THE COOLEST NIGHT
IN WELL OVER A WEEK. MIN TEMPS SHOULD FALL INTO THE MID 40S OVER THE
INTERIOR W HALF AND MOSTLY LOW/MID 50S ELSEWHERE.
DRY AIR MASS WILL SET UP A NICE WED UNDER PLENTY OF SUNSHINE. DWPTS
WILL BE LOW...MOSTLY IN THE 40S...WITH HIGH TEMPS IN THE UPPER 60S
TO MID 70S...WARMEST IN THE AREAS THAT SEE DOWNSLOPING UNDER A
WESTERLY WIND. SPEAKING OF WHICH...WINDS SHOULD BE GUSTY INTO THE 20
TO 30 MPH RANGE...ESPECIALLY OVER THE NW FCST AREA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 414 PM EDT TUE SEP 8 2015
THE UPPER TROUGH THAT IS CURRENTLY MOVING EAST ACROSS SOUTH CENTRAL
CANADA AND THE UPPER MISSISSIPPI VALLEY WILL MOVE INTO THE UPPER
GREAT LAKES OVER THE NEXT 12 HOURS AND THEN AMPLIFY OVER THE REGION
HEADING INTO THE END OF THE WORK WEEK AS A WAVE CURRENTLY MOVING
INTO BRITISH COLUMBIA ROTATES THROUGH. THIS SETUP WILL LEAD TO
GENERALLY BELOW NORMAL TEMPERATURES INTO THE START OF THE WEEKEND
WITH PERIODS OF SHOWERS.
AFTER A DRY START TO THE LONG TERM PERIOD ON WEDNESDAY EVENING
(DUE TO AN EXISTING HIGH PRESSURE RIDGE)...A WEAK SURFACE TROUGH
WILL MOVE EAST ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO THE
GREAT LAKES REGION LATER WEDNESDAY NIGHT AND THURSDAY. THIS WILL BE
IN RESPONSE TO THE SHORTWAVE CURRENTLY MOVING INTO BRITISH COLUMBIA
THAT WILL BE ROUNDING THE BASE OF THE UPPER TROUGH. SHOWERS ARE
EXPECTED TO DEVELOP IN SOUTHERN MINNESOTA AND WESTERN WISCONSIN
ON WEDNESDAY NIGHT AND THEN SPREADING EAST-NORTHEAST INTO PORTIONS
OF UPPER MICHIGAN. MODELS ARE DIFFERING ON THE NORTHWEST EXTENT OF
THE SHOWERS...LARGELY DUE TO THE TRACK OF THE SHORTWAVE WITH HALF
TRACKING IT ACROSS NORTHERN WISCONSIN (PUSHING PRECIP FARTHER NORTH)
AND THE OTHER HALF TRACK IT MORE ACROSS SOUTHERN WISCONSIN (AND HAS
PRECIP ONLY BRUSHING THE SOUTHERN THIRD OF THE AREA) ON THURSDAY.
DID SEE A SOUTHEAST TREND WITH THE 12Z ECMWF...WHICH IS MORE IN LINE
WITH THE 12Z GFS/GEM...SO WHILE CONFIDENCE IS LOW...FELT IT WAS
REASONABLE TO TREND THE CHANCE POPS FARTHER TO THE SOUTHEAST AND
MORE OVER THE SOUTH CENTRAL AND ALONG THE LAKE MICHIGAN SHORELINE.
THOSE SHOWERS WILL DEPART ON THURSDAY NIGHT AS THE SHORTWAVE AND
SURFACE TROUGH DEPARTS. THIS WILL ALLOW MUCH COLDER AIR TO SURGE
SOUTH ACROSS THE AREA THURSDAY NIGHT INTO FRIDAY...WITH 850MB TEMPS
FALLING TO 1-2C. SINCE LAKE SUPERIOR TEMPERATURES ARE IN THE 12-18C
RANGE...EXPECT SOME POTENTIAL OF LAKE EFFECT/ENHANCED RAIN FOR
THURSDAY NIGHT INTO FRIDAY. MODELS SHOWING DECENT MOISTURE BELOW
THE INVERSION AROUND 750MB...SO HAVE CHANCE POPS FOR THE FAVORED
NORTHERLY WIND LOCATIONS NEAR LAKE SUPERIOR DURING THAT TIME.
WILL LIKELY NEED TO TREND POPS UP FURTHER IF THE LATEST MODEL
TRENDS CONTINUE. IN ADDITION...THAT COLD AIR AND DECENT CLOUD COVER
FOR MUCH OF THE DAY ON FRIDAY WILL KEEP HIGHS IN THE 50S.
A SURFACE HIGH OFF TO THE WEST IN THE DAKOTAS WILL TRY TO PUSH A
SURFACE RIDGE INTO THE AREA ON FRIDAY...BUT IT WILL LIKELY REALLY
ARRIVE ON SATURDAY AS THE UPPER TROUGH BEGINS TO SHIFT EAST. DRIER
AIR ASSOCIATED WITH THE HIGH WILL LEAD TO DECREASING CLOUDS FROM
WEST TO EAST ON FRIDAY AFTERNOON...WITH CLEAR SKIES REMAINING IN
PLACE THROUGH MUCH OF THE WEEKEND. SATURDAY WILL REMAIN BELOW
NORMAL FOR HIGHS...BUT WITH THE UPPER RIDGE AXIS SHIFTING EAST FROM
THE DAKOTAS AND INTO THE UPPER GREAT LAKES REGION FOR SUNDAY AND
MONDAY...EXPECT HIGHS TO RISE BACK UP TO NORMAL OR EVEN SLIGHTLY
ABOVE NORMAL VALUES. WILL NEED TO WATCH THE EVOLUTION OF THE UPPER
TROUGH JUST TO THE EAST-SOUTHEAST OF THE AREA FOR SUNDAY/MONDAY
TIME FRAME...AS THERE ARE SOME HINTS OF IT ROTATING BACK NORTHWEST
AS THE UPPER RIDGE REMAINS FARTHER WEST. THAT WOULD LEAD TO COOLER
AND BETTER OPPORTUNITIES FOR RAIN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 150 PM EDT TUE SEP 8 2015
MUCH DRIER AIR WILL SWEEP INTO THE AREA BEHIND A DEPARTING
DISTURBANCE AND PASSING COLD FRONT. AT KIWD...VFR CONDITIONS WILL BE
THE RULE THROUGH THE FCST PERIOD. AT KCMX/KSAW...ANY LINGERING
IFR/LIFR CONDITIONS WILL CLEAR OUT IN THE NEXT HOUR OR TWO WITH VFR
CONDITIONS TO PREVAIL THEREAFTER. SHRA WILL ALSO END AT KSAW IN THE
NEXT FEW HRS. A PERIOD OF GUSTY WINDS UP TO 25KT WILL OCCUR BEHIND
FROPA AT KCMX THIS EVENING. GUSTY WINDS OF 18-25KT...STRONGEST AT
KCMX...ARE EXPECTED AT ALL TERMINALS BY LATE WED MORNING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 PM EDT TUE SEP 8 2015
FIRST UP...IF THERE IS ANY FOG ON LAKE SUPERIOR...IT WILL BE SWEPT
OFF THE ERN PORTION OF THE LAKE TONIGHT AS STRENGTHENING W WINDS
BEHIND A PASSING COLD FRONT USHER IN A MUCH DRIER AIR MASS TONIGHT.
INCOMING PRES RISES WILL HELP BOOST W WIND GUSTS TO 25-30KT FOR A
TIME AFTER FRONTAL PASSAGE. DURING WED...W WINDS OF 15-25KT WILL
GENERALLY BE THE RULE...BUT OVER CNTRL LAKE SUPERIOR AND IN
PARTICULAR AROUND THE TIP OF THE KEWEENAW PENINSULA...WINDS OF 20-
30KT ARE EXPECTED. LIGHTER WINDS OF 10-20KT ARE EXPECTED FOR WED
NIGHT/THU. ARRIVAL OF A COLDER AIR MASS AHEAD OF APPROACHING SFC
HIGH PRES WILL LEAD TO A PERIOD OF STRONGER WINDS OF 15-30KT AGAIN
THU NIGHT INTO AT LEAST FRI MORNING...STRONGEST OVER THE E HALF.
WINDS WILL SLOWLY DIMINISH W TO E FRI AFTN THRU SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
157 PM EDT TUE SEP 8 2015
.UPDATE...
SPC ANALYSIS SUPPORTS MODEL IDEA OF ML CAPE BUILDING TO AROUND
1500 J/KG THIS AFTERNOON. A FEW SHOWERS HAVE JUST STARTED TO POP
UP OVER SOUTHEAST MICHIGAN...IN ADDITION TO THE LINE OF
SHOWERS/TSTORMS THAT STRETCHES FROM CENTRAL LAKE MICHIGAN DOWN
THROUGH CHICAGO. LINE SHOULD BE MAINTAINED AND POTENTIALLY
STRENGTHEN AS IT WORKS INTO THE WARM UNSTABLE AIRMASS. BIGGEST
THREAT ASIDE FROM HEAVY RAINFALL WOULD BE WIND GUSTS TO 50 MPH
GIVEN STRONGER CORE OF WINDS ALOFT AND SOME DRIER AIR BELOW 4000
FEET.
&&
.AVIATION...
POCKET OF SUNSHINE WILL ALLOW SCT-BKN CUMULUS DECK TO FILL IN 18-
19Z...WITH CEILINGS LOOKING TO SETTLE IN THE 3500-5000 FT RANGE. THE
SUN HAS ALSO ALLOWED INSTABILITY TO BUILD...AND LINE OF
THUNDERSTORMS STRETCHING FROM CENTRAL LAKE MICHIGAN TO CHICAGO
SHOULD BE ABLE TO MAINTAIN ITSELF AS IT WORKS EAST DURING THE LATE
AFTERNOON AND EVENING. A 2-HR TEMPO WINDOW HAS BEEN ADDED INTO TAFS
TO HANDLE THIS LINE MOVING ACROSS THE TERMINALS...WITH PRELIMINARY
TIMING BETWEEN 20Z AND 02Z. AN AREA OF RAIN WITH EMBEDDED THUNDER
AND MVFR CEILINGS/VIS SHOULD THEN DROP DOWN INTO THE AREA FROM
NORTHERN MICHIGAN THIS EVENING AND OVERNIGHT AS WEAK LOW PRESSURE
TRACKS THROUGH THE REGION.
FOR DTW...LINE OF STORMS NEAR CHICAGO WILL PROGRESS WESTWARD THIS
AFTERNOON AND EVENING...POTENTIALLY STRENGTHENING. CURRENT TIMING
PER LINEAR EXTRAPOLATION WOULD BE AROUND 00Z...HOWEVER THE LINE
COULD SLOW AS IT BECOMES ORIENTATED TOWARDS FLOW OR EVEN SPEED UP IF
IT STRENGTHENS. HAVE INCLUDED A TEMPO GROUP BETWEEN 00Z AND 02Z TO
COVER...BUT ADJUSTMENTS COULD BE NECESSARY. AREA OF RAIN OVER
NORTHERN MICHIGAN IS EXPECTED TO DROP INTO THE AREA AROUND
04Z...DROPPING CEILINGS/VIS TO MVFR. A PERIOD OF IFR VISIBILITIES
COULD OCCUR BETWEEN WHEN THE RAIN ENDS AND WHEN A WEAK COLD FRONT
WORKS THROUGH WEDNESDAY MORNING.
//DTW THRESHOLD PROBABILITIES...
* MEDIUM FOR THUNDERSTORMS IN THE DTW AIRSPACE BEFORE 02Z. LOW
AFTER 02Z.
* MEDIUM FOR CIGS AOB 5KFT THIS AFTERNOON. HIGH OVERNIGHT AND EARLY
WEDNESDAY.
&&
.PREV DISCUSSION...ISSUED 340 AM EDT TUE SEP 8 2015
SHORT TERM...TODAY AND TONIGHT
ABSENT FORCING, THE RESERVOIR OF SIGNIFICANT MOISTURE ABOVE 700MB ON
LAST NIGHT`S 00Z DTX SOUNDING REMAINED QUIET THROUGH ABOUT 06Z.
HOWEVER, WARM ADVECTION WITHIN STRENGTHENING SWLY FLOW BEGAN TO
IGNITE CONVECTION ROUGHLY ALONG A CHICAGO TO PORT HURON LINE BY 07Z.
CONDITIONS WILL REMAIN FAVORABLE FOR EXPANSION OF THIS ACTIVITY
THROUGH THE MORNING AS FLOW CONTINUES TO INCREASE AND DAYTIME
HEATING ADDS A FEW HUNDRED J/KG CAPE TO THE PROFILE. THROUGH 18Z,
CONVECTION IS EXPECTED TO BE CONFINED MAINLY NORTH OF M59 ALONG WITH
THE BETTER FORCING. PWATS AROUND 2", LOW DENSITY CAPE, AND AN
INCREASINGLY DEEP WARM CLOUD LAYER WILL SUPPORT A HEAVY RAIN THREAT
FOR ANY AREAS THAT RECEIVE RAIN THROUGH TONIGHT. LOCALIZED FLOODING
IS NOT OUT OF THE QUESTION GIVEN SLOWER STORM MOTION AND THE
POTENTIAL FOR SOME AREAS ACROSS THE NORTHWEST TO SEE MULTIPLE ROUNDS
OF RAINFALL.
A SECOND AND STRONGER LLJ SURGE WILL ARRIVE BY AFTERNOON IN ADVANCE
OF THE SHORTWAVE NOTED OVER NORTHWEST MISSOURI AT 07Z THIS MORNING.
DYNAMIC FORCING WILL BE STOUT, BUT WILL ONLY OCCUR OVER A RELATIVELY
SMALL SPATIAL FOOTPRINT, MOST OF WHICH WILL BE OVER WESTERN AND
NORTHERN LOWER. HOWEVER, 06Z RAP INDICATES THAT THE CORE OF THE
ASSOCIATED 35-40KT LLJ WILL ALIGN ALONG A MUSKEGON TO WEST BRANCH
LINE 21-00Z WHICH WILL PUT THE SAGINAW VALLEY IN LINE TO RECEIVE A
NOTEWORTHY BOOST IN FORCING DUE TO DIFFERENTIAL WARM ADVECTION LATE
IN THE PEAK HEATING PERIOD. THUS, EVEN IF THE STRONGER DYNAMIC
FORCING DOES MANAGE TO MISS THE CWA...AND AT THIS TIME IT`S PROGGED
TO JUST GRAZE THE SAGINAW VALLEY AREA...NORTHWESTERN AREAS SHOULD
STILL SEE SOME EASTWARD EXPANSION OF CONVECTION DURING THE MID TO
LATE AFTERNOON DUE TO THE STRENGTHENING LLJ.
THE BULK OF THE RAIN SHIELD WILL EVENTUALLY PEEL NORTH ALONG WITH
THE DEPARTING WAVE, BUT LARGER SCALE FORCING EMBEDDED WITHIN THE
RIGHT ENTRANCE OF A 130KT UPPER JET OVER LAKE SUPERIOR WILL SUPPORT
A WAVE OF SHOWERS SLOWLY TRAVERSING THE REMAINDER OF THE AREA
ROUGHLY 00Z-12Z WED. THESE, TOO, WILL CARRY THE SAME THREAT FOR
HEAVY RAIN, THOUGH A DIMINISHED THREAT FOR FLOODING WILL EXIST DUE
TO INCREASINGLY PROGRESSIVE LARGER SCALE FORCING.
LONG TERM...
A STRONG WAVE ENTERING THE BASE OF THE MID/UPPER LEVEL TROUGH
CENTERED OVER WESTERN ONTARIO WILL PROVIDE THE NEEDED BOOST TO
USHER THE LINGERING FRONTAL BOUNDARY OFF TO THE EAST WEDNESDAY.
TIMING IS STILL NOT IRONED OUT EXACTLY AS THE INCOMING WESTERLY
JET MAX TURNS MORE NORTHEASTERLY ONCE IT PHASES WITH THE EXISTING
JET ALIGNED WITH THE FRONT. SO EXPECT THE FRONT TO BECOME MORE
PROGRESSIVE AS THE PARENT SYSTEM GAINS SPEED...BUT WITH THE SE
RIDGE STILL REACHING UP INTO THE EASTERN GREAT LAKES WE CAN EXPECT
SHOWERS TO LINGER OVER THE EASTERN COUNTIES INTO THE AFTERNOON
HOURS WEDNESDAY. THE FRONT WILL PUSH THE ENHANCED RIBBON OF
MOISTURE...NEAR 2 INCH PWATS...OFF TO THE EAST BY MIDDAY WEDNESDAY
BUT RESIDUAL MOISTURE POOL BETWEEN 1- 1.5 INCHES WILL STILL LINGER
THROUGH THE AFTERNOON UNTIL A SECONDARY TROUGH DROPS THROUGH LOWER
MI. THE NAM IS VERY BULLISH ON GENERATING SHOWERS WITH THIS
SECONDARY TROUGH IN PART DUE TO ELEVATED LL LAPSE RATES IN THE
WAKE OF THE FRONT. THERE IS SOME SIGNAL IN THE EURO/GFS BUT WITH
THE STRENGTH OF THE FRONTAL CIRCULATION...EXPECT A GOOD DEAL OF
SUBSIDENCE IN ITS WAKE COMBINED WITH THE BUILDING RIDGE. IN
ADDITION...THE NAM HAS BEEN DEVELOPING A SFC LOW ALONG THE FRONT
PASSING JUST TO OUR SOUTH THROUGH TOLEDO WEDNESDAY
AFTERNOON/EVENING. THIS WOULD RESULT IN ADDITIONAL DEFORMATION
FORCING LINGERING OVER SE MI AFTER 00Z THURSDAY. BUT AGAIN...NO
OTHER MODEL HAS ANYTHING NEARLY AS ORGANIZED AT THIS TIME.
SOMETHING TO WATCH BUT IN THE MEANTIME...FORECAST WILL FEATURE
CHANCE POPS DECREASING THROUGH THE DAY FROM NORTHWEST TO
SOUTHEAST.
WITH THE FRONT TO OUR SOUTH...PRECIP AND OVERCAST SKIES...HIGH
TEMPERATURES WILL TAKE A NOTABLE DIVE WEDNESDAY TOPPING OUT IN THE
UPPER 70S. THE SECONDARY TROUGH LATE WEDNESDAY WILL BRING ABOUT
COOLER WEATHER WITH NORTHERLY FLOW DROPPING HIGHS INTO THE MID 70S
FOR THURSDAY. TEMPS WILL TAKE A FURTHER NOSE DIVE INTO THE WEEKEND
AS YET ANOTHER FRONT SWEEPS THROUGH THE REGION ON FRIDAY BRINGING
THE NEXT CHANCE OF PRECIP WITH IT. MID MI MAY SEE SOME PRECIP
THURSDAY/THURSDAY NIGHT AS IT DRAPES SW TO NE THROUGH NORTHERN
LOWER...BUT MOST OF SE MI WILL REMAIN DRY TIL FRIDAY. MODELS DIVERGE
QUITE A BIT FOR THE WEEKEND IN THE HANDLING OF THIS NEXT UPPER
TROUGH...BUT CONSENSUS IS TROUGHING WILL HOLD OVER THE REGION WITH
ADDITIONAL SHOTS OF COOLER AIR WITH EACH FRONT. 850MB COLD POOL WILL
SET UP OVER THE GREAT LAKES WITH TEMPS POTENTIALLY DOWN INTO THE MID
SINGLE DIGITS AS HIGH PRESSURE SETTLES OVER THE REGION FROM CANADA.
MARINE...
A COLD FRONT DRAPED ACROSS THE CENTRAL GREAT LAKES IS RESULTING IN
WEAK FLOW WITHIN THE TROUGH OF LOW PRESSURE. THE EXCEPTION WOULD BE
LAKE ERIE AND LAKE ST CLAIR WHOM WILL CONTINUE TO RESIDE IN THE
SOUTHWESTERLY FLOW IN ADVANCE OF THE FRONT THROUGH THIS EVENING. THE
FRONT WILL BRING ABOUT A NOTABLE WIND SHIFT TONIGHT OVER LAKE HURON
TO NORTHWESTERLY...WHILE A TIGHTENED GRADIENT PROVIDES A BOOST TO
WIND SPEEDS WHICH WILL RANGE BETWEEN 20 AND 25 KNOTS POST COLD
FRONT. THIS FLOW WILL CONTINUE THROUGH WEDNESDAY AND WEDNESDAY NIGHT
AS A SECONDARY FRONT THEN DROPS THROUGH THE REGION. HIGH PRESSURE
WILL ALLOW WINDS TO RELAX ON THURSDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......HLO
AVIATION.....HLO
SHORT TERM...JVC
LONG TERM....DRK
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
119 PM EDT TUE SEP 8 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 329 AM EDT TUE SEP 8 2015
PERIODS OF SHOWERS AND THUNDERSTORMS WILL PREVAIL TODAY INTO THIS
EVENING BEFORE A SLOW MOVING COLD FRONT PUSHES THEM SOUTH OF THE
AREA BY MID MORNING WEDNESDAY. AREAS OF LOCALIZED HEAVY RAINFALL
ARE POSSIBLE. IT WILL CONTINUE TO BE VERY HUMID TODAY BUT NOT
QUIET AS WARM AS THE PAST FEW DAY. COOLER AND SIGNIFICANTLY DRIER
AIR WILL FOLLOW THE COLD FRONT FOR WEDNESDAY AND SUNSHINE SHOULD
PREVAIL IN MOST AREAS BY MID AFTERNOON. A SECONDARY COLD FRONT
WILL COME THROUGH THE AREA ON FRIDAY WITH SCATTERED SHOWERS. THIS
COMING WEEKEND SHOULD BE MOSTLY CLEAR WITH MUCH COOLER
TEMPERATURES...HIGHS MAY ONLY REACH THE MID 60S ON SATURDAY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
OUR PRIMARY ISSUE CONTINUES TO BE THE THREAT FOR HEAVY RAINFALL.
PRECIPITABLE WATER CONTINUES TO RUN BETWEEN 1.8 AND 2.0 INCHES
OVER MOST OF THE CWA TODAY. THIS IS AROUND 3 TIMES NORMAL AND IS
APPROACHING ALL TIME RECORD VALUES FOR THIS TIME OF YEAR. ADD TO
THAT A FRONTAL BOUNDARY SLOWLY MOVING THROUGH THE AREA...AIDED BY
THE ENTRANCE REGION OF THE POLAR JET AND A SHORTWAVE FROM IOWA...
AND THERE IS LITTLE QUESTION SOME OF THE STORMS WILL PRODUCE
HEAVY RAINFALL. CORFIDI VECTORS WILL BE BELOW 10 MILE PER HOUR
THIS MORNING AND RISE TO AROUND 15 MPH THIS AFTERNOON. THAT TOO
WILL AID IN THE LOCALLY HEAVY RAINFALL. I STILL BELIEVE SOME
ISOLATED RAINFALL AMOUNTS MAY BE CLOSE TO 5 INCHES FROM THIS
EVENT.
WE HAVE THE REMAINS OF YESTERDAYS OUTFLOW BOUNDARY STALLED
BETWEEN I-94 AND I-96 EARLY THIS MORNING. AS THE SHORTWAVE FROM
IOWA MOVES CLOSER TO THIS AREA WILL BE THE FOCUS FOR CONVECTION
THIS MORNING. WHICH SUGGESTS THE STORMS WILL MOSTLY BE SOUTH OF
I-96 AT FIRST BUT THEN LIFT NORTHWARD WITH TIME. BY LATE MORNING
INTO EARLY AFTERNOON I WOULD EXPECT MOST OF THE CONVECTION TO BE
NORTH OF I-96. THEN AS THE PRIMARY COLD FRONT AND SHORTWAVE MOVE
INTO THE AREA.. THE RAP MODEL SHOWS A 30 - 35 KNOT LOW LEVEL JET
MOVING INTO THE AREA BY MID AFTERNOON. THE CORE OF THE SPEED MAX
WILL BE JUST NORTH OF I-96 AND BE EAST OF MKG BY 4 PM AND BE NORTH
OF LANSING BY 8 PM. THIS SUGGEST TO ME THE STRONGEST CONVECTION
WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING.
THERE IS A MARGINAL RISK FOR SEVERE STORMS (SPC) TODAY... WITH THE
NARROW CAPE... AND NUMEROUS HEAVY SHOWERS AROUND... AND ONLY
MARGINAL DEEP LAYER SHEAR... I WOULD IMAGINE ANY SEVERE WEATHER
WOULD BE VERY ISOLATED TODAY.
ONCE THE COLD FRONT COMES THROUGH MOST OF THE CONVECTION WILL EXIT
WITH IT THIS EVENING. HIGH PRESSURE FOLLOWS FOR WEDNESDAY INTO
THURSDAY. CLEARING SKIES FROM NORTHWEST TO SOUTHEAST WEDNESDAY
AFTERNOON. I WOULD EXPECT MOSTLY CLEAR SKIES WEDNESDAY NIGHT INTO
THURSDAY AS THE HIGH MOVES OVERHEAD.
BOTTOM LINE IS WET TODAY...DRY WEDNESDAY AFTERNOON INTO THURSDAY
EVENING.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
A NICE COOL DOWN IS EXPECTED BY THE END OF THE WEEK AS A DEEP UPPER
TROUGH DEVELOPS OVER THE GREAT LAKES. WE/LL SEE TEMPERATURES IN THE
60S FRIDAY THROUGH SUNDAY ALONG WITH SOME SHOWERS FRIDAY AND
SATURDAY. MODEL CONCERNS ARE SIMILAR TO YESTERDAY AS THE ECMWF
DEEPENS THE LOW AND THEN CUTS IT OFF OVER MICHIGAN SUNDAY WHILE THE
GFS KEEPS THE SYSTEM AN OPEN WAVE AND THEN SCOOTS IT EASTWARD BY
SUNDAY. THE GFS WOULD LEAD TO WARMER TEMPS AND LESS PCPN THAN THE
SLOWER COOLER ECMWF. WE/RE LEANING TOWARD THE GFS SOLUTION AS IT
ALSO LINES UP NICELY WITH THE LATEST FIM. THUS ANY SHOWERS SHOULD
END BY LATE SATURDAY LEADING TO DRY WX SUNDAY AND MONDAY AND WARMER
TEMPS AS RIDGING BUILDS INTO SW LWR MI.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 115 PM EDT TUE SEP 8 2015
THE LINE OF THUNDERSTORMS APPROACHING KMKG WILL LIKELY CROSS THE
TAF SITES THROUGH THE AFTERNOON. THEREFORE I INCLUDED A BRIEF
PERIOD OF IFR AND GUSTY WINDS FOR EACH TAF SITE. AFTER THAT...IT
APPEARS LESS OF A RISK OF THUNDER.
FOG/STRATUS COULD BE AN ISSUE TONIGHT AS THE WIND DIMINISH AND THE
LOW LEVELS BECOME MORE HUMID. AS A RESULT I DID PUT MVFR/IFR CONDITIONS
IN THE FORECASTS.
&&
.MARINE...
ISSUED AT 1224 PM EDT TUE SEP 8 2015
NEARSHORE BOUYS FROM GRAND HAVEN TO LUDINGTON SHOWING WAVES OF 2
TO 4 FEET. LOOKS LIKE THE WAVES ARE ASSOCIATED WITH AN AREA OF
ENHANCED SOUTH WINDS OF 15 TO 20 KTS AHEAD OF THE APPROACHING COLD
FRONT AND THUNDERSTORM ACTIVITY. LARGEST WAVES OF 4FT SHOULD
CONTINUE TO SPREAD NORTHWARD TOWARDS LUDINGTON WHILE WAVES SHOULD
BEGIN TO SUBSIDE SOUTH OF MUSKEGON.
STILL EXPECTING VISIBILITY BELOW 1 MILE IN SHOWERS AND
THUNDERSTORMS THIS AFTERNOON AND CONTINUING INTO THIS EVENING
SOUTH OF MUSKEGON. FIRST BATCH WILL MOVE ONSHORE BY 6PM WITH A
SECOND AREA OF SHOWERS AND FOG OVER SOUTH HALF OF THE LAKE
OVERNIGHT.
POSSIBLY SCA FOR WED WITH GUSTY WEST WINDS BEHIND COLD FRONT.
LOOKING FOR OCCASIONAL GUSTS TO 25 KTS AND BUILDING SEAS OF 3 TO 5
FEET THROUGH THE AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 1207 AM EDT TUE SEP 8 2015
A FLOOD ADVISORY IS ONGOING FOR HOLT ON THE SYCAMORE CREEK. THE
STAGE CONTINUES TO RISE...BUT THE RATE OF RISE IS NOT QUITE AS
STEEP AS IT WAS EARLIER THIS MORNING. CURRENT CRESTS THAT ARE
FORECAST WILL BE HIGHLY DEPENDENT ON TONIGHTS RAINFALL AMOUNTS.
A COMPLEX OF SHOWERS AND THUNDERSTORMS THAT DEVELOPED OVER THE
UPPER MIDWEST LATE LAST NIGHT CONTINUE TO PROGRESS NORTHEAST
THROUGH THE NORTHERN GREAT LAKES. A LINE OF SHOWERS AND
THUNDERSTORMS CURRENTLY EXTENDS FROM CENTRAL LAKE MICHIGAN AND
SOUTHWEST INTO ILLINOIS. THIS LINE CONTINUES TO EXPAND AS IT
PRESSES EASTWARD. FOR SOME LOCATIONS...THIS WILL BE THE SECOND
ROUND OF RAINFALL TODAY. HEAVY RAIN OF ONE TO TWO INCHES IS
POSSIBLE...ESPECIALLY IN OR NEAR THUNDERSTORMS.
ANOTHER WAVE OF PRECIPITATION MAY DEVELOP FURTHER SOUTH AND WEST
OVERNIGHT...ACROSS THE SOUTHERN HALF OF LOWER MICHIGAN...WHICH
COULD BRING ADDITIONAL PERIODS OF HEAVY RAIN. OVERALL RAINFALL
TOTALS COULD EXCEED TWO INCHES IN LOCATIONS AFFECTED BY REPEATED
EVENTS. LOCALIZED FLOODING TO URBAN AREAS AND PONDING OF ROADWAYS
COULD OCCUR DURING AND CLOSELY FOLLOWING HEAVY RAINFALL. AREAS
STREAMS AND RIVERS MAY RISE DUE TO QUICK RUNOFF AS MANY LOCATIONS
ALREADY HAVE SATURATED SOILS.
DRY WEATHER IS ANTICIPATED TO RETURN BY MID MORNING WEDNESDAY.
THIS SHOULD ALLOW RIVERS TIME TO STABILIZE WEDNESDAY INTO
THURSDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...MJS
HYDROLOGY...JAM
MARINE...COBB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
100 PM EDT TUE SEP 8 2015
.UPDATE...
ISSUED AT 959 AM EDT TUE SEP 8 2015
SHOWERS AND EMBEDDED THUNDERSTORMS ARE STEADILY EXPANDING IN AREAL
COVERAGE ACROSS THE SRN HALF OF OUR CWA LATE THIS MORNING AS DEEP
MOISTURE SURGES NORTH INTO NORTHERN MICHIGAN AHEAD OF A LARGE AREA
OF WIDESPREAD CONVECTION. LATEST DAY 1 OUTLOOK HAS EXPANDED THE
MARGINAL AREA INTO MUCH OF NRN LWR MICHIGAN...ANTICIPATING SOME
DIURNAL DESTABILIZATION THIS AFTERNOON COMBINED WITH SOME INCREASE
IN WIND SPEEDS WELL ALOFT AT THE ANVIL LEVEL. LATEST RAP13 IS
RATHER AGGRESSIVE IN BOOSTING MUCAPES THIS
AFTERNOON...APPROACHING 1700 JOULES IN OUR SE CWA. MEANWHILE...THE
LATEST HRRR SEEMS TO BE UNIMPRESSED WITH THE PROSPECT OF DIURNAL
DESTABILIZATION... SUGGESTING CAPES WILL ONLY REACH TO 250-500
JOULES. LATEST NAM12 LIES SOMEWHERE IN BETWEEN. TEND TO SIDE WITH
THE HRRR GIVEN AMPLE CLOUDS AND PRECIP ACROSS OUR ENTIRE
CWA...INCLUDING OUR SE CWA WHERE THE OTHER TWO MODELS SHOW
GREATEST DESTABILIZATION.
STILL EXPECT SVR CHANCES ARE MINIMAL...BUT WILL CERTAINLY MAINTAIN
CHANCES OF THUNDER ACROSS OUR ENTIRE CWA THRU TODAY AND INTO
EARLY EVENING. WILL ALSO KEEP CATEGORICAL POPS FOR MUCH OF NRN LWR
MICHIGAN...AND WILL KEEP A CLOSE EYE ON ERN UPR MICHIGAN WHERE WE
MAY NEED TO INCREASE POPS FROM LIKELY TO CATEGORICAL AS THIS EVENT
PLAYS OUT TODAY.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 431 AM EDT TUE SEP 8 2015
...WET DAY AHEAD BUT LAST DAY OF HUMIDITY...
HIGH IMPACT WEATHER POTENTIAL: LOCALLY HEAVY DOWNPOURS POSSIBLE
TODAY.
PATTERN SYNOPSIS/FORECAST: MIDNIGHT SURFACE/COMPOSITE ANALYSIS SHOWS
A COLD FRONT DRAPED ACROSS NORTHEAST/CENTRAL LOWER MICHIGAN AND
EXTENDING BACK ACROSS SOUTHERN LAKE MICHIGAN AND ALONG THE
WISCONSIN/ILLINOIS BORDER INTO SOUTHERN IOWA. SMALL BUBBLE OF HIGH
PRESSURE (1017MB) WAS CENTERED OVER THE MINNESOTA ARROWHEAD. SOUPY
AIR MASS LINGERS OVER THE UPPER LAKES AND POINTS SOUTH AND
SOUTHWEST...GOES PRECIPITABLE WATER ANALYSIS SHOWS AN ARC OF 40-50MM
VALUES FROM THE LOWER LAKES/SOUTHERN LOWER MICHIGAN BACK TO THE MID
MISSISSIPPI VALLEY AND THE EASTERN PLAINS. 00Z APX SOUNDING DOES
SHOW SOME ELEVATED INSTABILITY (ON THE ORDER OF 1200J/KG MUCAPE)...A
FEW SPOTTY SHOWERS HAVE BEEN POPPING UP SOUTH OF M-32 LIKELY
ASSOCIATED WITH WEAK ISENTROPIC ASCENT AS OVERALL WIND FLOW IS LIGHT
BELOW 700MB...WITH A ROUGE SHOWER OVER LUCE COUNTY. MORE WIDESPREAD
RAINFALL HAS BEEN CONGEALING OVER THE MIDWEST.
DIFFUSE FRONT LYING ACROSS LOWER MICHIGAN WILL LIKELY BE MOSTLY
STATIONARY TODAY...BUT WITH PLENTY OF MOISTURE AROUND. STRONGER
SHORT WAVE TROUGH OVER THE ROCKIES WILL PUSH INTO THE UPPER
MIDWEST/UPPER LAKES TONIGHT...WHICH IN TURN WILL ALLOW A SECONDARY
COLD FRONT TO SLICE ACROSS MICHIGAN OVERNIGHT AND FINALLY KNOCK DOWN
THIS PERSISTENTLY HUMID AIR MASS.
PRIMARY FORECAST CONCERNS: DETAILS REGARDING RAINFALL OVER NEXT 24
HOURS.
TODAY...LOOKS LIKE TODAY SHOULD BE RELATIVELY STRAIGHTFORWARD...AS
COMBINATION OF WHAT IS CURRENTLY POPPING OVER LOWER MICHIGAN...AND
ARRIVAL LATER THIS MORNING OF UPSTREAM PRECIPITATION EXPECTED TO
RESULT IN PERIODS OF RAIN...ALONG WITH SOME EMBEDDED THUNDER. AS
HAS BEEN THE CASE RECENTLY...PRECIPITATION SHOULD BE PRETTY
EFFICIENT GIVEN DEEP LAYER MOISTURE (PRECIPITABLE WATER 1.50-2.00
INCHES EXPECTED AND A FAIRLY DEEP WARM LAYER). GENERAL RAINFALL
AMOUNTS OF 0.50-1.00 INCH EXPECTED ACROSS NORTHERN LOWER MICHIGAN...
WITH HIGHER AMOUNTS POSSIBLE DEPENDING ON EVOLUTION OF PRECIPITATION
THOUGH THAT IS SOMEWHAT UNCERTAIN GIVEN RATHER WEAK FOCUSING
MECHANISMS.
TONIGHT...COUPLE ROUNDS OF PRECIPITATION POSSIBLE FOR TONIGHT. LAST
OF THE DAYTIME PRECIPITATION WILL BE PUSHING INTO LAKE HURON DURING
THE MID-LATE EVENING HOURS...AND GIVEN LIGHT FLOW WILL PROBABLY BE
FOLLOWED BY FOG/STRATUS DEVELOPMENT. APPROACH OF SECONDARY COLD
FRONT AND ASSOCIATED SHORT WAVE TROUGH...AS WELL AS RIGHT ENTRANCE
JET FORCING MAY RESULT IN SCATTERED ADDITIONAL DEVELOPMENT AS THIS
FRONT PASSES.
&&
.SHORT TERM...(WEDNESDAY THROUGH THURSDAY NIGHT)
ISSUED AT 431 AM EDT TUE SEP 8 2015
HIGH IMPACT WEATHER: NONE
(9/9)WEDNESDAY...MODELS HAVE COME TOGETHER AND NOW HAVE THE RAIN OUT
OF THE AREA. THE SFC HIGH PRESSURE BUILDS INTO THE LOWER MICHIGAN
AND HOLDS THROUGH THE DAY AND MOST OF THE NIGHT. A SFC TROUGH BEGINS
TO DEVELOP IN RESPONSE TO THE 500 MB SHORTWAVE TROUGH JUST UPSTREAM
IN MINNESOTA, AND ALONG THE THERMAL GRADIENT RUNNING THROUGH LAKE
SUPERIOR, BETWEEN 06Z AND 12Z WHICH BEGINS TO PRODUCE RAIN TO THE
WEST, IN WISCONSIN. AT THIS POINT, IT LOOKS LIKE THE RAIN SHOULD
STAY WEST, AS THE NAM/ECMWF CONTINUE TO KEEP THE SHORTWAVE TROUGH TO
FARTHER WEST THAN THE GFS.
(9/10)THURSDAY...THE SFC RIDGE BREAKS DOWN AS THE 500 MB SHORTWAVE
PUSHES, THE COLD FRONT THROUGH THE REGION. INSTABILITY IS PRETTY
SMALL, AND SINCE WE ALREADY HAVE RAIN SHOWERS WITH A SLIGHT CHANCE
OF THUNDER, WILL KEEP THAT AT THIS POINT, BUT GETTING THE FEELING
WITH THE COOLER SFC TEMPERATURES (IN THE LOWER 70S WEDNESDAY AND
THURSDAY) THAT THERE WON`T BE REALLY ENOUGH INSTABILITY FOR THUNDER.
THEN OVERNIGHT, THE RAIN SHOWERS, OR MAYBE IT WILL JUST BE AN AREA
OF RAIN, SET UPS WAS THE SHORTWAVE AND TROUGH MOVES INTO THE REGION.
AS THE SHORTWAVE PROGRESSIVELY MOVES IN, COLDER 850 MB AIR CONTINUES
INTO THE REGION AS WELL SO THAT WE WILL PROBABLY SET UP LAKE EFFECT
RAIN, ALTHOUGH WITH THE 1000-850 MB LAYER WIND OUT OF THE NORTH-
NORTHEAST, WE`LL STAY OUT OF IT INITIALLY UNTIL FRIDAY.
&&
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 431 AM EDT TUE SEP 8 2015
EXTENDED (FRIDAY THROUGH MONDAY)...THE MODELS ARE BEGINNING TO COME
TOGETHER ON THE EVOLUTION OF THE DIGGING 500 MB SHORTWAVE TROUGH
OVER THE GREAT LAKES. THE ECMWF ISN`T AS DEEP OR CUT OFF AND THE GFS
IS A LITTLE DEEPER. THE ECMWF DOES PUSH THE RAIN THROUGH FASTER AS
WELL AS THE CUT OFF SO THAT THE TIMING THE END OF THE RAIN ON FRIDAY
IS PRETTY CLOSE AND THAT THE COOL DRY WEATHER WILL CONTINUE ON
SATURDAY. SUNDAY, TOO, LOOKS DRY, AND THEN A COLD FRONT PUSHES INTO
THE REGION ON THE GFS SUNDAY NIGHT INTO MONDAY, WHILE THE ECMWF IS
DRY UNTIL MONDAY NIGHT. ONE OTHER CONCERN IS FOR FRIDAY...THERE IS A
LOW END THREAT FOR WATERSPOUTS WITH AN UPPER LOW, DELTA TS OF 16C
AND CLOUD DEPTHS OF 5000-10000 FEET.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 100 PM EDT TUE SEP 8 2015
WIDESPREAD RAIN WITH EMBEDDED THUNDERSTORMS WILL CONTINUE TO
IMPACT ALL NRN LWR MICHIGAN TAF SITES THIS AFTERNOON AND INTO
EARLY EVENING AS A VIGOROUS WAVE SLIDES THRU THE AREA AHEAD OF AN
APPROACHING COLD FRONT. OVERALL CONDITIONS WILL REMAIN IFR...WITH
SOME BRIEF MOMENTS OF MVFR CONDITIONS. ALL PRECIP SHOULD END BY
AROUND 00Z THIS EVENING. ANY AMOUNT OF CLEARING AFTER THE PRECIP
ENDS WILL VERY TEMPORARY AS AREAS OF FOG AND STRATUS REDEVELOP
LATER THIS EVENING AND OVERNIGHT THANKS TO AMPLE LOW LEVEL
MOISTURE LINGERING BEHIND THE FRONT. CONDITIONS SHOULD RETURN TO
VFR WEDNESDAY MORNING AS MUCH DRIER LOW LEVEL AIR PUSHES INTO THE
REGION AND DIURNAL MIXING LENDS A HAND AS WELL.
&&
.MARINE...
ISSUED AT 431 AM EDT TUE SEP 8 2015
TODAY/TONIGHT...LIGHT WINDS TODAY AND TONIGHT...ONLY MARINE ISSUE
WILL BE POOR VISIBILITY IN FOG.
OUTLOOK...WINDS WILL PICK UP FROM THE NORTHWEST WEDNESDAY BEHIND A
COLD FRONT CROSSING THE UPPER LAKES TUESDAY NIGHT. WINDS WILL BE
GUSTY WITHIN NORTHERN LAKE HURON ZONES WITH COASTAL CONVERGENCE...
MAY BE CLOSE TO SMALL CRAFT CRITERIA.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...MLR
NEAR TERM...JPB
SHORT TERM...JSL
LONG TERM...JSL
AVIATION...MLR
MARINE...JPB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1232 PM EDT TUE SEP 8 2015
LATEST UPDATE...
MARINE
.SYNOPSIS...
ISSUED AT 329 AM EDT TUE SEP 8 2015
PERIODS OF SHOWERS AND THUNDERSTORMS WILL PREVAIL TODAY INTO THIS
EVENING BEFORE A SLOW MOVING COLD FRONT PUSHES THEM SOUTH OF THE
AREA BY MID MORNING WEDNESDAY. AREAS OF LOCALIZED HEAVY RAINFALL
ARE POSSIBLE. IT WILL CONTINUE TO BE VERY HUMID TODAY BUT NOT
QUIET AS WARM AS THE PAST FEW DAY. COOLER AND SIGNIFICANTLY DRIER
AIR WILL FOLLOW THE COLD FRONT FOR WEDNESDAY AND SUNSHINE SHOULD
PREVAIL IN MOST AREAS BY MID AFTERNOON. A SECONDARY COLD FRONT
WILL COME THROUGH THE AREA ON FRIDAY WITH SCATTERED SHOWERS. THIS
COMING WEEKEND SHOULD BE MOSTLY CLEAR WITH MUCH COOLER
TEMPERATURES...HIGHS MAY ONLY REACH THE MID 60S ON SATURDAY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
OUR PRIMARY ISSUE CONTINUES TO BE THE THREAT FOR HEAVY RAINFALL.
PRECIPITABLE WATER CONTINUES TO RUN BETWEEN 1.8 AND 2.0 INCHES
OVER MOST OF THE CWA TODAY. THIS IS AROUND 3 TIMES NORMAL AND IS
APPROACHING ALL TIME RECORD VALUES FOR THIS TIME OF YEAR. ADD TO
THAT A FRONTAL BOUNDARY SLOWLY MOVING THROUGH THE AREA...AIDED BY
THE ENTRANCE REGION OF THE POLAR JET AND A SHORTWAVE FROM IOWA...
AND THERE IS LITTLE QUESTION SOME OF THE STORMS WILL PRODUCE
HEAVY RAINFALL. CORFIDI VECTORS WILL BE BELOW 10 MILE PER HOUR
THIS MORNING AND RISE TO AROUND 15 MPH THIS AFTERNOON. THAT TOO
WILL AID IN THE LOCALLY HEAVY RAINFALL. I STILL BELIEVE SOME
ISOLATED RAINFALL AMOUNTS MAY BE CLOSE TO 5 INCHES FROM THIS
EVENT.
WE HAVE THE REMAINS OF YESTERDAYS OUTFLOW BOUNDARY STALLED
BETWEEN I-94 AND I-96 EARLY THIS MORNING. AS THE SHORTWAVE FROM
IOWA MOVES CLOSER TO THIS AREA WILL BE THE FOCUS FOR CONVECTION
THIS MORNING. WHICH SUGGESTS THE STORMS WILL MOSTLY BE SOUTH OF
I-96 AT FIRST BUT THEN LIFT NORTHWARD WITH TIME. BY LATE MORNING
INTO EARLY AFTERNOON I WOULD EXPECT MOST OF THE CONVECTION TO BE
NORTH OF I-96. THEN AS THE PRIMARY COLD FRONT AND SHORTWAVE MOVE
INTO THE AREA.. THE RAP MODEL SHOWS A 30 - 35 KNOT LOW LEVEL JET
MOVING INTO THE AREA BY MID AFTERNOON. THE CORE OF THE SPEED MAX
WILL BE JUST NORTH OF I-96 AND BE EAST OF MKG BY 4 PM AND BE NORTH
OF LANSING BY 8 PM. THIS SUGGEST TO ME THE STRONGEST CONVECTION
WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING.
THERE IS A MARGINAL RISK FOR SEVERE STORMS (SPC) TODAY... WITH THE
NARROW CAPE... AND NUMEROUS HEAVY SHOWERS AROUND... AND ONLY
MARGINAL DEEP LAYER SHEAR... I WOULD IMAGINE ANY SEVERE WEATHER
WOULD BE VERY ISOLATED TODAY.
ONCE THE COLD FRONT COMES THROUGH MOST OF THE CONVECTION WILL EXIT
WITH IT THIS EVENING. HIGH PRESSURE FOLLOWS FOR WEDNESDAY INTO
THURSDAY. CLEARING SKIES FROM NORTHWEST TO SOUTHEAST WEDNESDAY
AFTERNOON. I WOULD EXPECT MOSTLY CLEAR SKIES WEDNESDAY NIGHT INTO
THURSDAY AS THE HIGH MOVES OVERHEAD.
BOTTOM LINE IS WET TODAY...DRY WEDNESDAY AFTERNOON INTO THURSDAY
EVENING.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
A NICE COOL DOWN IS EXPECTED BY THE END OF THE WEEK AS A DEEP UPPER
TROUGH DEVELOPS OVER THE GREAT LAKES. WE/LL SEE TEMPERATURES IN THE
60S FRIDAY THROUGH SUNDAY ALONG WITH SOME SHOWERS FRIDAY AND
SATURDAY. MODEL CONCERNS ARE SIMILAR TO YESTERDAY AS THE ECMWF
DEEPENS THE LOW AND THEN CUTS IT OFF OVER MICHIGAN SUNDAY WHILE THE
GFS KEEPS THE SYSTEM AN OPEN WAVE AND THEN SCOOTS IT EASTWARD BY
SUNDAY. THE GFS WOULD LEAD TO WARMER TEMPS AND LESS PCPN THAN THE
SLOWER COOLER ECMWF. WE/RE LEANING TOWARD THE GFS SOLUTION AS IT
ALSO LINES UP NICELY WITH THE LATEST FIM. THUS ANY SHOWERS SHOULD
END BY LATE SATURDAY LEADING TO DRY WX SUNDAY AND MONDAY AND WARMER
TEMPS AS RIDGING BUILDS INTO SW LWR MI.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 745 AM EDT TUE SEP 8 2015
CURRENTLY MOSTLY VFR CONDITIONS PREVAIL AT OUR TAF SITES. THERE
IS A BAND OF CONVECTION (WEST TO EAST) LIFTING NORTHWARD HEAD OF
THE SHORTWAVE COMING OUT OF IOWA. THIS BAND OF CONVECTION SHOULD
BE NORTH OF THE TAF STIES BY 16Z OR SO. THEN THE CONVECTION WITH
THE COLD FRONT WILL CROSS THE TAF SITES BETWEEN 22Z AND 03Z FROM
WEST TO EAST. SHOWERS WILL THEN PREVAIL FOR FEW HOURS ONCE THE
COLD FRONT IS THROUGH. ONCE THE SHOWERS END EXPECT A FEW HOURS OF
MVFR CIGS.
&&
.MARINE...
ISSUED AT 1224 PM EDT TUE SEP 8 2015
NEARSHORE BOUYS FROM GRAND HAVEN TO LUDINGTON SHOWING WAVES OF 2
TO 4 FEET. LOOKS LIKE THE WAVES ARE ASSOCIATED WITH AN AREA OF
ENHANCED SOUTH WINDS OF 15 TO 20 KTS AHEAD OF THE APPROACHING COLD
FRONT AND THUNDERSTORM ACTIVITY. LARGEST WAVES OF 4FT SHOULD
CONTINUE TO SPREAD NORTHWARD TOWARDS LUDINGTON WHILE WAVES SHOULD
BEGIN TO SUBSIDE SOUTH OF MUSKEGON.
STILL EXPECTING VISIBILITY BELOW 1 MILE IN SHOWERS AND
THUNDERSTORMS THIS AFTERNOON AND CONTINUING INTO THIS EVENING
SOUTH OF MUSKEGON. FIRST BATCH WILL MOVE ONSHORE BY 6PM WITH A
SECOND AREA OF SHOWERS AND FOG OVER SOUTH HALF OF THE LAKE
OVERNIGHT.
POSSIBLY SCA FOR WED WITH GUSTY WEST WINDS BEHIND COLD FRONT.
LOOKING FOR OCCASIONAL GUSTS TO 25 KTS AND BUILDING SEAS OF 3 TO 5
FEET THROUGH THE AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 1207 AM EDT TUE SEP 8 2015
A FLOOD ADVISORY IS ONGOING FOR HOLT ON THE SYCAMORE CREEK. THE
STAGE CONTINUES TO RISE...BUT THE RATE OF RISE IS NOT QUITE AS
STEEP AS IT WAS EARLIER THIS MORNING. CURRENT CRESTS THAT ARE
FORECAST WILL BE HIGHLY DEPENDENT ON TONIGHTS RAINFALL AMOUNTS.
A COMPLEX OF SHOWERS AND THUNDERSTORMS THAT DEVELOPED OVER THE
UPPER MIDWEST LATE LAST NIGHT CONTINUE TO PROGRESS NORTHEAST
THROUGH THE NORTHERN GREAT LAKES. A LINE OF SHOWERS AND
THUNDERSTORMS CURRENTLY EXTENDS FROM CENTRAL LAKE MICHIGAN AND
SOUTHWEST INTO ILLINOIS. THIS LINE CONTINUES TO EXPAND AS IT
PRESSES EASTWARD. FOR SOME LOCATIONS...THIS WILL BE THE SECOND
ROUND OF RAINFALL TODAY. HEAVY RAIN OF ONE TO TWO INCHES IS
POSSIBLE...ESPECIALLY IN OR NEAR THUNDERSTORMS.
ANOTHER WAVE OF PRECIPITATION MAY DEVELOP FURTHER SOUTH AND WEST
OVERNIGHT...ACROSS THE SOUTHERN HALF OF LOWER MICHIGAN...WHICH
COULD BRING ADDITIONAL PERIODS OF HEAVY RAIN. OVERALL RAINFALL
TOTALS COULD EXCEED TWO INCHES IN LOCATIONS AFFECTED BY REPEATED
EVENTS. LOCALIZED FLOODING TO URBAN AREAS AND PONDING OF ROADWAYS
COULD OCCUR DURING AND CLOSELY FOLLOWING HEAVY RAINFALL. AREAS
STREAMS AND RIVERS MAY RISE DUE TO QUICK RUNOFF AS MANY LOCATIONS
ALREADY HAVE SATURATED SOILS.
DRY WEATHER IS ANTICIPATED TO RETURN BY MID MORNING WEDNESDAY.
THIS SHOULD ALLOW RIVERS TIME TO STABILIZE WEDNESDAY INTO
THURSDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...WDM
HYDROLOGY...JAM
MARINE...COBB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1207 PM EDT TUE SEP 8 2015
LATEST UPDATE...
HYDRO
.SYNOPSIS...
ISSUED AT 329 AM EDT TUE SEP 8 2015
PERIODS OF SHOWERS AND THUNDERSTORMS WILL PREVAIL TODAY INTO THIS
EVENING BEFORE A SLOW MOVING COLD FRONT PUSHES THEM SOUTH OF THE
AREA BY MID MORNING WEDNESDAY. AREAS OF LOCALIZED HEAVY RAINFALL
ARE POSSIBLE. IT WILL CONTINUE TO BE VERY HUMID TODAY BUT NOT
QUIET AS WARM AS THE PAST FEW DAY. COOLER AND SIGNIFICANTLY DRIER
AIR WILL FOLLOW THE COLD FRONT FOR WEDNESDAY AND SUNSHINE SHOULD
PREVAIL IN MOST AREAS BY MID AFTERNOON. A SECONDARY COLD FRONT
WILL COME THROUGH THE AREA ON FRIDAY WITH SCATTERED SHOWERS. THIS
COMING WEEKEND SHOULD BE MOSTLY CLEAR WITH MUCH COOLER
TEMPERATURES...HIGHS MAY ONLY REACH THE MID 60S ON SATURDAY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
OUR PRIMARY ISSUE CONTINUES TO BE THE THREAT FOR HEAVY RAINFALL.
PRECIPITABLE WATER CONTINUES TO RUN BETWEEN 1.8 AND 2.0 INCHES
OVER MOST OF THE CWA TODAY. THIS IS AROUND 3 TIMES NORMAL AND IS
APPROACHING ALL TIME RECORD VALUES FOR THIS TIME OF YEAR. ADD TO
THAT A FRONTAL BOUNDARY SLOWLY MOVING THROUGH THE AREA...AIDED BY
THE ENTRANCE REGION OF THE POLAR JET AND A SHORTWAVE FROM IOWA...
AND THERE IS LITTLE QUESTION SOME OF THE STORMS WILL PRODUCE
HEAVY RAINFALL. CORFIDI VECTORS WILL BE BELOW 10 MILE PER HOUR
THIS MORNING AND RISE TO AROUND 15 MPH THIS AFTERNOON. THAT TOO
WILL AID IN THE LOCALLY HEAVY RAINFALL. I STILL BELIEVE SOME
ISOLATED RAINFALL AMOUNTS MAY BE CLOSE TO 5 INCHES FROM THIS
EVENT.
WE HAVE THE REMAINS OF YESTERDAYS OUTFLOW BOUNDARY STALLED
BETWEEN I-94 AND I-96 EARLY THIS MORNING. AS THE SHORTWAVE FROM
IOWA MOVES CLOSER TO THIS AREA WILL BE THE FOCUS FOR CONVECTION
THIS MORNING. WHICH SUGGESTS THE STORMS WILL MOSTLY BE SOUTH OF
I-96 AT FIRST BUT THEN LIFT NORTHWARD WITH TIME. BY LATE MORNING
INTO EARLY AFTERNOON I WOULD EXPECT MOST OF THE CONVECTION TO BE
NORTH OF I-96. THEN AS THE PRIMARY COLD FRONT AND SHORTWAVE MOVE
INTO THE AREA.. THE RAP MODEL SHOWS A 30 - 35 KNOT LOW LEVEL JET
MOVING INTO THE AREA BY MID AFTERNOON. THE CORE OF THE SPEED MAX
WILL BE JUST NORTH OF I-96 AND BE EAST OF MKG BY 4 PM AND BE NORTH
OF LANSING BY 8 PM. THIS SUGGEST TO ME THE STRONGEST CONVECTION
WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING.
THERE IS A MARGINAL RISK FOR SEVERE STORMS (SPC) TODAY... WITH THE
NARROW CAPE... AND NUMEROUS HEAVY SHOWERS AROUND... AND ONLY
MARGINAL DEEP LAYER SHEAR... I WOULD IMAGINE ANY SEVERE WEATHER
WOULD BE VERY ISOLATED TODAY.
ONCE THE COLD FRONT COMES THROUGH MOST OF THE CONVECTION WILL EXIT
WITH IT THIS EVENING. HIGH PRESSURE FOLLOWS FOR WEDNESDAY INTO
THURSDAY. CLEARING SKIES FROM NORTHWEST TO SOUTHEAST WEDNESDAY
AFTERNOON. I WOULD EXPECT MOSTLY CLEAR SKIES WEDNESDAY NIGHT INTO
THURSDAY AS THE HIGH MOVES OVERHEAD.
BOTTOM LINE IS WET TODAY...DRY WEDNESDAY AFTERNOON INTO THURSDAY
EVENING.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
A NICE COOL DOWN IS EXPECTED BY THE END OF THE WEEK AS A DEEP UPPER
TROUGH DEVELOPS OVER THE GREAT LAKES. WE/LL SEE TEMPERATURES IN THE
60S FRIDAY THROUGH SUNDAY ALONG WITH SOME SHOWERS FRIDAY AND
SATURDAY. MODEL CONCERNS ARE SIMILAR TO YESTERDAY AS THE ECMWF
DEEPENS THE LOW AND THEN CUTS IT OFF OVER MICHIGAN SUNDAY WHILE THE
GFS KEEPS THE SYSTEM AN OPEN WAVE AND THEN SCOOTS IT EASTWARD BY
SUNDAY. THE GFS WOULD LEAD TO WARMER TEMPS AND LESS PCPN THAN THE
SLOWER COOLER ECMWF. WE/RE LEANING TOWARD THE GFS SOLUTION AS IT
ALSO LINES UP NICELY WITH THE LATEST FIM. THUS ANY SHOWERS SHOULD
END BY LATE SATURDAY LEADING TO DRY WX SUNDAY AND MONDAY AND WARMER
TEMPS AS RIDGING BUILDS INTO SW LWR MI.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 745 AM EDT TUE SEP 8 2015
CURRENTLY MOSTLY VFR CONDITIONS PREVAIL AT OUR TAF SITES. THERE
IS A BAND OF CONVECTION (WEST TO EAST) LIFTING NORTHWARD HEAD OF
THE SHORTWAVE COMING OUT OF IOWA. THIS BAND OF CONVECTION SHOULD
BE NORTH OF THE TAF STIES BY 16Z OR SO. THEN THE CONVECTION WITH
THE COLD FRONT WILL CROSS THE TAF SITES BETWEEN 22Z AND 03Z FROM
WEST TO EAST. SHOWERS WILL THEN PREVAIL FOR FEW HOURS ONCE THE
COLD FRONT IS THROUGH. ONCE THE SHOWERS END EXPECT A FEW HOURS OF
MVFR CIGS.
&&
.MARINE...
ISSUED AT 329 AM EDT TUE SEP 8 2015
WINDS AND WAVES SHOULD REMAIN BELOW SMALL CRAFT CRITERIA THROUGH
THURSDAY. EVEN SO THERE MAY BE GUSTY WINDS IN SOME OF THE
THUNDERSTORMS TODAY. VISIBILITIES MAY BE REDUCED TO BELOW A HALF
MILE IN SOME OF THE HEAVY THUNDERSTORMS TODAY.
&&
.HYDROLOGY...
ISSUED AT 1207 AM EDT TUE SEP 8 2015
A FLOOD ADVISORY IS ONGOING FOR HOLT ON THE SYCAMORE CREEK. THE
STAGE CONTINUES TO RISE...BUT THE RATE OF RISE IS NOT QUITE AS
STEEP AS IT WAS EARLIER THIS MORNING. CURRENT CRESTS THAT ARE
FORECAST WILL BE HIGHLY DEPENDENT ON TONIGHTS RAINFALL AMOUNTS.
A COMPLEX OF SHOWERS AND THUNDERSTORMS THAT DEVELOPED OVER THE
UPPER MIDWEST LATE LAST NIGHT CONTINUE TO PROGRESS NORTHEAST
THROUGH THE NORTHERN GREAT LAKES. A LINE OF SHOWERS AND
THUNDERSTORMS CURRENTLY EXTENDS FROM CENTRAL LAKE MICHIGAN AND
SOUTHWEST INTO ILLINOIS. THIS LINE CONTINUES TO EXPAND AS IT
PRESSES EASTWARD. FOR SOME LOCATIONS...THIS WILL BE THE SECOND
ROUND OF RAINFALL TODAY. HEAVY RAIN OF ONE TO TWO INCHES IS
POSSIBLE...ESPECIALLY IN OR NEAR THUNDERSTORMS.
ANOTHER WAVE OF PRECIPITATION MAY DEVELOP FURTHER SOUTH AND WEST
OVERNIGHT...ACROSS THE SOUTHERN HALF OF LOWER MICHIGAN...WHICH
COULD BRING ADDITIONAL PERIODS OF HEAVY RAIN. OVERALL RAINFALL
TOTALS COULD EXCEED TWO INCHES IN LOCATIONS AFFECTED BY REPEATED
EVENTS. LOCALIZED FLOODING TO URBAN AREAS AND PONDING OF ROADWAYS
COULD OCCUR DURING AND CLOSELY FOLLOWING HEAVY RAINFALL. AREAS
STREAMS AND RIVERS MAY RISE DUE TO QUICK RUNOFF AS MANY LOCATIONS
ALREADY HAVE SATURATED SOILS.
DRY WEATHER IS ANTICIPATED TO RETURN BY MID MORNING WEDNESDAY.
THIS SHOULD ALLOW RIVERS TIME TO STABILIZE WEDNESDAY INTO
THURSDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...WDM
HYDROLOGY...JAM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1138 AM EDT TUE SEP 8 2015
LATEST UPDATE...
MESOSCALE DISCUSSION
.MESOSCALE DISCUSSION...
ISSUED AT 1137 AM EDT TUE SEP 8 2015
15Z SURFACE ANALYSIS INDICATED A WARM FRONT AND ASSOCIATED
PRECIPITATION LIFTING NORTH INTO NORTHERN LOWER MICHIGAN. SURFACE
LOW WAS LOCATED OVER SOUTHEAST WISCONSIN. SHOWERS AND THUNDERSTORMS
EXTENDED FROM THE LOW INTO NORTHWEST ILLINOIS ALONG A PREFRONTAL
TROUGH. THIS PRECIPITATION IS TIMED TO MOVE ACROSS SOUTHWEST LOWER
MICHIGAN IN THE 2-3 PM TIMEFRAME.
THE 12Z DTX SOUNDING INDICATED PRECIPITABLE WATER AT 1.93" WHICH IS
NEAR RECORD LEVELS FOR THIS TIME OF YEAR. VISIBLE SATELLITE SUGGESTS
A COUPLE HOUR WINDOW OF CLEARING/DESTABILIZATION NEAR THE I-94
CORRIDOR...WHERE POTENTIAL FOR DAMAGING WINDS WILL BE ELEVATED.
HOWEVER...OVERALL INSTABILITY SHOULD REMAIN MARGINAL...FURTHER
CONTRIBUTING TO AN ENVIRONMENT WITH HIGH PRECIPITATION EFFICIENCIES.
WE ARE LEANING TOWARDS RECENT ESRL EXPERIMENTAL HRRR RUNS THAT
DEPICT AN ADDITIONAL ROUND OF PRECIPITATION SPREADING ACROSS MOST OF
SOUTHERN LOWER MICHIGAN BEHIND THE MENTIONED FIRST WAVE. THIS WOULD
CONTINUE THE PRECIPITATION THREAT WELL INTO EVENING. FIM/GFS/ECMWF
MODELS AGREE ON A STRENGTHENING JET ALOFT BEHIND THE INITIAL WAVE OF
PRECIPITATION...SO FRONTOGENESIS AND ASSOCIATED UPWARD VERTICAL
MOTION ALOFT LOOK PROBABLE AND SUPPORT THE IDEA OF A SECOND BATCH OF
RAIN.
&&
.SYNOPSIS...
ISSUED AT 329 AM EDT TUE SEP 8 2015
PERIODS OF SHOWERS AND THUNDERSTORMS WILL PREVAIL TODAY INTO THIS
EVENING BEFORE A SLOW MOVING COLD FRONT PUSHES THEM SOUTH OF THE
AREA BY MID MORNING WEDNESDAY. AREAS OF LOCALIZED HEAVY RAINFALL
ARE POSSIBLE. IT WILL CONTINUE TO BE VERY HUMID TODAY BUT NOT
QUIET AS WARM AS THE PAST FEW DAY. COOLER AND SIGNIFICANTLY DRIER
AIR WILL FOLLOW THE COLD FRONT FOR WEDNESDAY AND SUNSHINE SHOULD
PREVAIL IN MOST AREAS BY MID AFTERNOON. A SECONDARY COLD FRONT
WILL COME THROUGH THE AREA ON FRIDAY WITH SCATTERED SHOWERS. THIS
COMING WEEKEND SHOULD BE MOSTLY CLEAR WITH MUCH COOLER
TEMPERATURES...HIGHS MAY ONLY REACH THE MID 60S ON SATURDAY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
OUR PRIMARY ISSUE CONTINUES TO BE THE THREAT FOR HEAVY RAINFALL.
PRECIPITABLE WATER CONTINUES TO RUN BETWEEN 1.8 AND 2.0 INCHES
OVER MOST OF THE CWA TODAY. THIS IS AROUND 3 TIMES NORMAL AND IS
APPROACHING ALL TIME RECORD VALUES FOR THIS TIME OF YEAR. ADD TO
THAT A FRONTAL BOUNDARY SLOWLY MOVING THROUGH THE AREA...AIDED BY
THE ENTRANCE REGION OF THE POLAR JET AND A SHORTWAVE FROM IOWA...
AND THERE IS LITTLE QUESTION SOME OF THE STORMS WILL PRODUCE
HEAVY RAINFALL. CORFIDI VECTORS WILL BE BELOW 10 MILE PER HOUR
THIS MORNING AND RISE TO AROUND 15 MPH THIS AFTERNOON. THAT TOO
WILL AID IN THE LOCALLY HEAVY RAINFALL. I STILL BELIEVE SOME
ISOLATED RAINFALL AMOUNTS MAY BE CLOSE TO 5 INCHES FROM THIS
EVENT.
WE HAVE THE REMAINS OF YESTERDAYS OUTFLOW BOUNDARY STALLED
BETWEEN I-94 AND I-96 EARLY THIS MORNING. AS THE SHORTWAVE FROM
IOWA MOVES CLOSER TO THIS AREA WILL BE THE FOCUS FOR CONVECTION
THIS MORNING. WHICH SUGGESTS THE STORMS WILL MOSTLY BE SOUTH OF
I-96 AT FIRST BUT THEN LIFT NORTHWARD WITH TIME. BY LATE MORNING
INTO EARLY AFTERNOON I WOULD EXPECT MOST OF THE CONVECTION TO BE
NORTH OF I-96. THEN AS THE PRIMARY COLD FRONT AND SHORTWAVE MOVE
INTO THE AREA.. THE RAP MODEL SHOWS A 30 - 35 KNOT LOW LEVEL JET
MOVING INTO THE AREA BY MID AFTERNOON. THE CORE OF THE SPEED MAX
WILL BE JUST NORTH OF I-96 AND BE EAST OF MKG BY 4 PM AND BE NORTH
OF LANSING BY 8 PM. THIS SUGGEST TO ME THE STRONGEST CONVECTION
WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING.
THERE IS A MARGINAL RISK FOR SEVERE STORMS (SPC) TODAY... WITH THE
NARROW CAPE... AND NUMEROUS HEAVY SHOWERS AROUND... AND ONLY
MARGINAL DEEP LAYER SHEAR... I WOULD IMAGINE ANY SEVERE WEATHER
WOULD BE VERY ISOLATED TODAY.
ONCE THE COLD FRONT COMES THROUGH MOST OF THE CONVECTION WILL EXIT
WITH IT THIS EVENING. HIGH PRESSURE FOLLOWS FOR WEDNESDAY INTO
THURSDAY. CLEARING SKIES FROM NORTHWEST TO SOUTHEAST WEDNESDAY
AFTERNOON. I WOULD EXPECT MOSTLY CLEAR SKIES WEDNESDAY NIGHT INTO
THURSDAY AS THE HIGH MOVES OVERHEAD.
BOTTOM LINE IS WET TODAY...DRY WEDNESDAY AFTERNOON INTO THURSDAY
EVENING.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
A NICE COOL DOWN IS EXPECTED BY THE END OF THE WEEK AS A DEEP UPPER
TROUGH DEVELOPS OVER THE GREAT LAKES. WE/LL SEE TEMPERATURES IN THE
60S FRIDAY THROUGH SUNDAY ALONG WITH SOME SHOWERS FRIDAY AND
SATURDAY. MODEL CONCERNS ARE SIMILAR TO YESTERDAY AS THE ECMWF
DEEPENS THE LOW AND THEN CUTS IT OFF OVER MICHIGAN SUNDAY WHILE THE
GFS KEEPS THE SYSTEM AN OPEN WAVE AND THEN SCOOTS IT EASTWARD BY
SUNDAY. THE GFS WOULD LEAD TO WARMER TEMPS AND LESS PCPN THAN THE
SLOWER COOLER ECMWF. WE/RE LEANING TOWARD THE GFS SOLUTION AS IT
ALSO LINES UP NICELY WITH THE LATEST FIM. THUS ANY SHOWERS SHOULD
END BY LATE SATURDAY LEADING TO DRY WX SUNDAY AND MONDAY AND WARMER
TEMPS AS RIDGING BUILDS INTO SW LWR MI.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 745 AM EDT TUE SEP 8 2015
CURRENTLY MOSTLY VFR CONDITIONS PREVAIL AT OUR TAF SITES. THERE
IS A BAND OF CONVECTION (WEST TO EAST) LIFTING NORTHWARD HEAD OF
THE SHORTWAVE COMING OUT OF IOWA. THIS BAND OF CONVECTION SHOULD
BE NORTH OF THE TAF STIES BY 16Z OR SO. THEN THE CONVECTION WITH
THE COLD FRONT WILL CROSS THE TAF SITES BETWEEN 22Z AND 03Z FROM
WEST TO EAST. SHOWERS WILL THEN PREVAIL FOR FEW HOURS ONCE THE
COLD FRONT IS THROUGH. ONCE THE SHOWERS END EXPECT A FEW HOURS OF
MVFR CIGS.
&&
.MARINE...
ISSUED AT 329 AM EDT TUE SEP 8 2015
WINDS AND WAVES SHOULD REMAIN BELOW SMALL CRAFT CRITERIA THROUGH
THURSDAY. EVEN SO THERE MAY BE GUSTY WINDS IN SOME OF THE
THUNDERSTORMS TODAY. VISIBILITIES MAY BE REDUCED TO BELOW A HALF
MILE IN SOME OF THE HEAVY THUNDERSTORMS TODAY.
&&
.HYDROLOGY...
ISSUED AT 1142 AM EDT MON SEP 7 2015
WE MAY RUN THE RISK FOR MINOR FLOODING BETWEEN LATE TONIGHT
THROUGH EARLY WEDNESDAY AS HEAVY RAIN IS POISED TO MARCH ACROSS
THE FORECAST AREA.
A SLOW MOVING FRONTAL BOUNDARY WILL BECOME NEARLY STATIONARY LATE
TONIGHT AND DURING THE DAY TUESDAY. FORECAST PRECIPITABLE WATER
VALUES OF AROUND 2.0 INCHES REMAINS UNCHANGED SINCE PRIOR
FORECASTS. TIMING SEEMS TO BE THE MOST CONSISTENT WITH THIS EVENT.
WHILE RAINFALL WILL BE POSSIBLE FROM TONIGHT THROUGH EARLY WEDNESDAY
AFTERNOON...THE HEAVIEST RAIN IS EXPECTED BETWEEN TUESDAY EVENING
AND WEDNESDAY MORNING.
THE ENTIRE FORECAST AREA CAN COUNT ON ABOUT AND INCH OF
PRECIPITATION...WHILE THE HEAVIEST SWATH LANDS NEAR AND NORTH OF
GRAND RAPIDS. 1-3 SEEMS REALISTIC ALONG AND NORTH OF I-96. THE
CATCH HERE IS THAT THE SOUTHERN HALF OF THE FORECAST AREA...SOUTH
OF I-96 REMAINS ENTRENCHED IN THE WARM SECTOR AND COULD EXPERIENCE
HIGHER INSTANTANEOUS RAINFALL RATES. THIS MEANS THAT HEAVY RAINFALL
THAT DEVELOPS IN SOUTHERN SECTIONS OF THE FORECAST AREA...MAY
RESULT IN LOCALIZED HIGHER TOTALS...4-5 INCHES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
MESOSCALE...TJT
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...WDM
HYDROLOGY...JAM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GAYLORD MI
959 AM EDT TUE SEP 8 2015
.UPDATE...
ISSUED AT 959 AM EDT TUE SEP 8 2015
SHOWERS AND EMBEDDED THUNDERSTORMS ARE STEADILY EXPANDING IN AREAL
COVERAGE ACROSS THE SRN HALF OF OUR CWA LATE THIS MORNING AS DEEP
MOISTURE SURGES NORTH INTO NORTHERN MICHIGAN AHEAD OF A LARGE AREA
OF WIDESPREAD CONVECTION. LATEST DAY 1 OUTLOOK HAS EXPANDED THE
MARGINAL AREA INTO MUCH OF NRN LWR MICHIGAN...ANTICIPATING SOME
DIURNAL DESTABILIZATION THIS AFTERNOON COMBINED WITH SOME INCREASE
IN WIND SPEEDS WELL ALOFT AT THE ANVIL LEVEL. LATEST RAP13 IS
RATHER AGGRESSIVE IN BOOSTING MUCAPES THIS
AFTERNOON...APPROACHING 1700 JOULES IN OUR SE CWA. MEANWHILE...THE
LATEST HRRR SEEMS TO BE UNIMPRESSED WITH THE PROSPECT OF DIURNAL
DESTABILIZATION... SUGGESTING CAPES WILL ONLY REACH TO 250-500
JOULES. LATEST NAM12 LIES SOMEWHERE IN BETWEEN. TEND TO SIDE WITH
THE HRRR GIVEN AMPLE CLOUDS AND PRECIP ACROSS OUR ENTIRE
CWA...INCLUDING OUR SE CWA WHERE THE OTHER TWO MODELS SHOW
GREATEST DESTABILIZATION.
STILL EXPECT SVR CHANCES ARE MINIMAL...BUT WILL CERTAINLY MAINTAIN
CHANCES OF THUNDER ACROSS OUR ENTIRE CWA THRU TODAY AND INTO
EARLY EVENING. WILL ALSO KEEP CATEGORICAL POPS FOR MUCH OF NRN LWR
MICHIGAN...AND WILL KEEP A CLOSE EYE ON ERN UPR MICHIGAN WHERE WE
MAY NEED TO INCREASE POPS FROM LIKELY TO CATEGORICAL AS THIS EVENT
PLAYS OUT TODAY.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 431 AM EDT TUE SEP 8 2015
...WET DAY AHEAD BUT LAST DAY OF HUMIDITY...
HIGH IMPACT WEATHER POTENTIAL: LOCALLY HEAVY DOWNPOURS POSSIBLE
TODAY.
PATTERN SYNOPSIS/FORECAST: MIDNIGHT SURFACE/COMPOSITE ANALYSIS SHOWS
A COLD FRONT DRAPED ACROSS NORTHEAST/CENTRAL LOWER MICHIGAN AND
EXTENDING BACK ACROSS SOUTHERN LAKE MICHIGAN AND ALONG THE
WISCONSIN/ILLINOIS BORDER INTO SOUTHERN IOWA. SMALL BUBBLE OF HIGH
PRESSURE (1017MB) WAS CENTERED OVER THE MINNESOTA ARROWHEAD. SOUPY
AIR MASS LINGERS OVER THE UPPER LAKES AND POINTS SOUTH AND
SOUTHWEST...GOES PRECIPITABLE WATER ANALYSIS SHOWS AN ARC OF 40-50MM
VALUES FROM THE LOWER LAKES/SOUTHERN LOWER MICHIGAN BACK TO THE MID
MISSISSIPPI VALLEY AND THE EASTERN PLAINS. 00Z APX SOUNDING DOES
SHOW SOME ELEVATED INSTABILITY (ON THE ORDER OF 1200J/KG MUCAPE)...A
FEW SPOTTY SHOWERS HAVE BEEN POPPING UP SOUTH OF M-32 LIKELY
ASSOCIATED WITH WEAK ISENTROPIC ASCENT AS OVERALL WIND FLOW IS LIGHT
BELOW 700MB...WITH A ROUGE SHOWER OVER LUCE COUNTY. MORE WIDESPREAD
RAINFALL HAS BEEN CONGEALING OVER THE MIDWEST.
DIFFUSE FRONT LYING ACROSS LOWER MICHIGAN WILL LIKELY BE MOSTLY
STATIONARY TODAY...BUT WITH PLENTY OF MOISTURE AROUND. STRONGER
SHORT WAVE TROUGH OVER THE ROCKIES WILL PUSH INTO THE UPPER
MIDWEST/UPPER LAKES TONIGHT...WHICH IN TURN WILL ALLOW A SECONDARY
COLD FRONT TO SLICE ACROSS MICHIGAN OVERNIGHT AND FINALLY KNOCK DOWN
THIS PERSISTENTLY HUMID AIR MASS.
PRIMARY FORECAST CONCERNS: DETAILS REGARDING RAINFALL OVER NEXT 24
HOURS.
TODAY...LOOKS LIKE TODAY SHOULD BE RELATIVELY STRAIGHTFORWARD...AS
COMBINATION OF WHAT IS CURRENTLY POPPING OVER LOWER MICHIGAN...AND
ARRIVAL LATER THIS MORNING OF UPSTREAM PRECIPITATION EXPECTED TO
RESULT IN PERIODS OF RAIN...ALONG WITH SOME EMBEDDED THUNDER. AS
HAS BEEN THE CASE RECENTLY...PRECIPITATION SHOULD BE PRETTY
EFFICIENT GIVEN DEEP LAYER MOISTURE (PRECIPITABLE WATER 1.50-2.00
INCHES EXPECTED AND A FAIRLY DEEP WARM LAYER). GENERAL RAINFALL
AMOUNTS OF 0.50-1.00 INCH EXPECTED ACROSS NORTHERN LOWER MICHIGAN...
WITH HIGHER AMOUNTS POSSIBLE DEPENDING ON EVOLUTION OF PRECIPITATION
THOUGH THAT IS SOMEWHAT UNCERTAIN GIVEN RATHER WEAK FOCUSING
MECHANISMS.
TONIGHT...COUPLE ROUNDS OF PRECIPITATION POSSIBLE FOR TONIGHT. LAST
OF THE DAYTIME PRECIPITATION WILL BE PUSHING INTO LAKE HURON DURING
THE MID-LATE EVENING HOURS...AND GIVEN LIGHT FLOW WILL PROBABLY BE
FOLLOWED BY FOG/STRATUS DEVELOPMENT. APPROACH OF SECONDARY COLD
FRONT AND ASSOCIATED SHORT WAVE TROUGH...AS WELL AS RIGHT ENTRANCE
JET FORCING MAY RESULT IN SCATTERED ADDITIONAL DEVELOPMENT AS THIS
FRONT PASSES.
&&
.SHORT TERM...(WEDNESDAY THROUGH THURSDAY NIGHT)
ISSUED AT 431 AM EDT TUE SEP 8 2015
HIGH IMPACT WEATHER: NONE
(9/9)WEDNESDAY...MODELS HAVE COME TOGETHER AND NOW HAVE THE RAIN OUT
OF THE AREA. THE SFC HIGH PRESSURE BUILDS INTO THE LOWER MICHIGAN
AND HOLDS THROUGH THE DAY AND MOST OF THE NIGHT. A SFC TROUGH BEGINS
TO DEVELOP IN RESPONSE TO THE 500 MB SHORTWAVE TROUGH JUST UPSTREAM
IN MINNESOTA, AND ALONG THE THERMAL GRADIENT RUNNING THROUGH LAKE
SUPERIOR, BETWEEN 06Z AND 12Z WHICH BEGINS TO PRODUCE RAIN TO THE
WEST, IN WISCONSIN. AT THIS POINT, IT LOOKS LIKE THE RAIN SHOULD
STAY WEST, AS THE NAM/ECMWF CONTINUE TO KEEP THE SHORTWAVE TROUGH TO
FARTHER WEST THAN THE GFS.
(9/10)THURSDAY...THE SFC RIDGE BREAKS DOWN AS THE 500 MB SHORTWAVE
PUSHES, THE COLD FRONT THROUGH THE REGION. INSTABILITY IS PRETTY
SMALL, AND SINCE WE ALREADY HAVE RAIN SHOWERS WITH A SLIGHT CHANCE
OF THUNDER, WILL KEEP THAT AT THIS POINT, BUT GETTING THE FEELING
WITH THE COOLER SFC TEMPERATURES (IN THE LOWER 70S WEDNESDAY AND
THURSDAY) THAT THERE WON`T BE REALLY ENOUGH INSTABILITY FOR THUNDER.
THEN OVERNIGHT, THE RAIN SHOWERS, OR MAYBE IT WILL JUST BE AN AREA
OF RAIN, SET UPS WAS THE SHORTWAVE AND TROUGH MOVES INTO THE REGION.
AS THE SHORTWAVE PROGRESSIVELY MOVES IN, COLDER 850 MB AIR CONTINUES
INTO THE REGION AS WELL SO THAT WE WILL PROBABLY SET UP LAKE EFFECT
RAIN, ALTHOUGH WITH THE 1000-850 MB LAYER WIND OUT OF THE NORTH-
NORTHEAST, WE`LL STAY OUT OF IT INITIALLY UNTIL FRIDAY.
&&
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 431 AM EDT TUE SEP 8 2015
EXTENDED (FRIDAY THROUGH MONDAY)...THE MODELS ARE BEGINNING TO COME
TOGETHER ON THE EVOLUTION OF THE DIGGING 500 MB SHORTWAVE TROUGH
OVER THE GREAT LAKES. THE ECMWF ISN`T AS DEEP OR CUT OFF AND THE GFS
IS A LITTLE DEEPER. THE ECMWF DOES PUSH THE RAIN THROUGH FASTER AS
WELL AS THE CUT OFF SO THAT THE TIMING THE END OF THE RAIN ON FRIDAY
IS PRETTY CLOSE AND THAT THE COOL DRY WEATHER WILL CONTINUE ON
SATURDAY. SUNDAY, TOO, LOOKS DRY, AND THEN A COLD FRONT PUSHES INTO
THE REGION ON THE GFS SUNDAY NIGHT INTO MONDAY, WHILE THE ECMWF IS
DRY UNTIL MONDAY NIGHT. ONE OTHER CONCERN IS FOR FRIDAY...THERE IS A
LOW END THREAT FOR WATERSPOUTS WITH AN UPPER LOW, DELTA TS OF 16C
AND CLOUD DEPTHS OF 5000-10000 FEET.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 703 AM EDT TUE SEP 8 2015
ANTICIPATED IFR CONDITIONS TO DEVELOP ALL TERMINALS BY MID-LATE
MORNING...FOG/STRATUS WILL BE AN ISSUE AGAIN TONIGHT PRIOR TO
FRONTAL PASSAGE.
&&
.MARINE...
ISSUED AT 431 AM EDT TUE SEP 8 2015
TODAY/TONIGHT...LIGHT WINDS TODAY AND TONIGHT...ONLY MARINE ISSUE
WILL BE POOR VISIBILITY IN FOG.
OUTLOOK...WINDS WILL PICK UP FROM THE NORTHWEST WEDNESDAY BEHIND A
COLD FRONT CROSSING THE UPPER LAKES TUESDAY NIGHT. WINDS WILL BE
GUSTY WITHIN NORTHERN LAKE HURON ZONES WITH COASTAL CONVERGENCE...
MAY BE CLOSE TO SMALL CRAFT CRITERIA.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...MLR
NEAR TERM...JPB
SHORT TERM...JSL
LONG TERM...JSL
MARINE...JPB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
745 AM EDT TUE SEP 8 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 329 AM EDT TUE SEP 8 2015
PERIODS OF SHOWERS AND THUNDERSTORMS WILL PREVAIL TODAY INTO THIS
EVENING BEFORE A SLOW MOVING COLD FRONT PUSHES THEM SOUTH OF THE
AREA BY MID MORNING WEDNESDAY. AREAS OF LOCALIZED HEAVY RAINFALL
ARE POSSIBLE. IT WILL CONTINUE TO BE VERY HUMID TODAY BUT NOT
QUIET AS WARM AS THE PAST FEW DAY. COOLER AND SIGNIFICANTLY DRIER
AIR WILL FOLLOW THE COLD FRONT FOR WEDNESDAY AND SUNSHINE SHOULD
PREVAIL IN MOST AREAS BY MID AFTERNOON. A SECONDARY COLD FRONT
WILL COME THROUGH THE AREA ON FRIDAY WITH SCATTERED SHOWERS. THIS
COMING WEEKEND SHOULD BE MOSTLY CLEAR WITH MUCH COOLER
TEMPERATURES...HIGHS MAY ONLY REACH THE MID 60S ON SATURDAY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
OUR PRIMARY ISSUE CONTINUES TO BE THE THREAT FOR HEAVY RAINFALL.
PRECIPITABLE WATER CONTINUES TO RUN BETWEEN 1.8 AND 2.0 INCHES
OVER MOST OF THE CWA TODAY. THIS IS AROUND 3 TIMES NORMAL AND IS
APPROACHING ALL TIME RECORD VALUES FOR THIS TIME OF YEAR. ADD TO
THAT A FRONTAL BOUNDARY SLOWLY MOVING THROUGH THE AREA...AIDED BY
THE ENTRANCE REGION OF THE POLAR JET AND A SHORTWAVE FROM IOWA...
AND THERE IS LITTLE QUESTION SOME OF THE STORMS WILL PRODUCE
HEAVY RAINFALL. CORFIDI VECTORS WILL BE BELOW 10 MILE PER HOUR
THIS MORNING AND RISE TO AROUND 15 MPH THIS AFTERNOON. THAT TOO
WILL AID IN THE LOCALLY HEAVY RAINFALL. I STILL BELIEVE SOME
ISOLATED RAINFALL AMOUNTS MAY BE CLOSE TO 5 INCHES FROM THIS
EVENT.
WE HAVE THE REMAINS OF YESTERDAYS OUTFLOW BOUNDARY STALLED
BETWEEN I-94 AND I-96 EARLY THIS MORNING. AS THE SHORTWAVE FROM
IOWA MOVES CLOSER TO THIS AREA WILL BE THE FOCUS FOR CONVECTION
THIS MORNING. WHICH SUGGESTS THE STORMS WILL MOSTLY BE SOUTH OF
I-96 AT FIRST BUT THEN LIFT NORTHWARD WITH TIME. BY LATE MORNING
INTO EARLY AFTERNOON I WOULD EXPECT MOST OF THE CONVECTION TO BE
NORTH OF I-96. THEN AS THE PRIMARY COLD FRONT AND SHORTWAVE MOVE
INTO THE AREA.. THE RAP MODEL SHOWS A 30 - 35 KNOT LOW LEVEL JET
MOVING INTO THE AREA BY MID AFTERNOON. THE CORE OF THE SPEED MAX
WILL BE JUST NORTH OF I-96 AND BE EAST OF MKG BY 4 PM AND BE NORTH
OF LANSING BY 8 PM. THIS SUGGEST TO ME THE STRONGEST CONVECTION
WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING.
THERE IS A MARGINAL RISK FOR SEVERE STORMS (SPC) TODAY... WITH THE
NARROW CAPE... AND NUMEROUS HEAVY SHOWERS AROUND... AND ONLY
MARGINAL DEEP LAYER SHEAR... I WOULD IMAGINE ANY SEVERE WEATHER
WOULD BE VERY ISOLATED TODAY.
ONCE THE COLD FRONT COMES THROUGH MOST OF THE CONVECTION WILL EXIT
WITH IT THIS EVENING. HIGH PRESSURE FOLLOWS FOR WEDNESDAY INTO
THURSDAY. CLEARING SKIES FROM NORTHWEST TO SOUTHEAST WEDNESDAY
AFTERNOON. I WOULD EXPECT MOSTLY CLEAR SKIES WEDNESDAY NIGHT INTO
THURSDAY AS THE HIGH MOVES OVERHEAD.
BOTTOM LINE IS WET TODAY...DRY WEDNESDAY AFTERNOON INTO THURSDAY
EVENING.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
A NICE COOL DOWN IS EXPECTED BY THE END OF THE WEEK AS A DEEP UPPER
TROUGH DEVELOPS OVER THE GREAT LAKES. WE/LL SEE TEMPERATURES IN THE
60S FRIDAY THROUGH SUNDAY ALONG WITH SOME SHOWERS FRIDAY AND
SATURDAY. MODEL CONCERNS ARE SIMILAR TO YESTERDAY AS THE ECMWF
DEEPENS THE LOW AND THEN CUTS IT OFF OVER MICHIGAN SUNDAY WHILE THE
GFS KEEPS THE SYSTEM AN OPEN WAVE AND THEN SCOOTS IT EASTWARD BY
SUNDAY. THE GFS WOULD LEAD TO WARMER TEMPS AND LESS PCPN THAN THE
SLOWER COOLER ECMWF. WE/RE LEANING TOWARD THE GFS SOLUTION AS IT
ALSO LINES UP NICELY WITH THE LATEST FIM. THUS ANY SHOWERS SHOULD
END BY LATE SATURDAY LEADING TO DRY WX SUNDAY AND MONDAY AND WARMER
TEMPS AS RIDGING BUILDS INTO SW LWR MI.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 745 AM EDT TUE SEP 8 2015
CURRENTLY MOSTLY VFR CONDITIONS PREVAIL AT OUR TAF SITES. THERE
IS A BAND OF CONVECTION (WEST TO EAST) LIFTING NORTHWARD HEAD OF
THE SHORTWAVE COMING OUT OF IOWA. THIS BAND OF CONVECTION SHOULD
BE NORTH OF THE TAF STIES BY 16Z OR SO. THEN THE CONVECTION WITH
THE COLD FRONT WILL CROSS THE TAF SITES BETWEEN 22Z AND 03Z FROM
WEST TO EAST. SHOWERS WILL THEN PREVAIL FOR FEW HOURS ONCE THE
COLD FRONT IS THROUGH. ONCE THE SHOWERS END EXPECT A FEW HOURS OF
MVFR CIGS.
&&
.MARINE...
ISSUED AT 329 AM EDT TUE SEP 8 2015
WINDS AND WAVES SHOULD REMAIN BELOW SMALL CRAFT CRITERIA THROUGH
THURSDAY. EVEN SO THERE MAY BE GUSTY WINDS IN SOME OF THE
THUNDERSTORMS TODAY. VISIBILITIES MAY BE REDUCED TO BELOW A HALF
MILE IN SOME OF THE HEAVY THUNDERSTORMS TODAY.
&&
.HYDROLOGY...
ISSUED AT 1142 AM EDT MON SEP 7 2015
WE MAY RUN THE RISK FOR MINOR FLOODING BETWEEN LATE TONIGHT
THROUGH EARLY WEDNESDAY AS HEAVY RAIN IS POISED TO MARCH ACROSS
THE FORECAST AREA.
A SLOW MOVING FRONTAL BOUNDARY WILL BECOME NEARLY STATIONARY LATE
TONIGHT AND DURING THE DAY TUESDAY. FORECAST PRECIPITABLE WATER
VALUES OF AROUND 2.0 INCHES REMAINS UNCHANGED SINCE PRIOR
FORECASTS. TIMING SEEMS TO BE THE MOST CONSISTENT WITH THIS EVENT.
WHILE RAINFALL WILL BE POSSIBLE FROM TONIGHT THROUGH EARLY WEDNESDAY
AFTERNOON...THE HEAVIEST RAIN IS EXPECTED BETWEEN TUESDAY EVENING
AND WEDNESDAY MORNING.
THE ENTIRE FORECAST AREA CAN COUNT ON ABOUT AND INCH OF
PRECIPITATION...WHILE THE HEAVIEST SWATH LANDS NEAR AND NORTH OF
GRAND RAPIDS. 1-3 SEEMS REALISTIC ALONG AND NORTH OF I-96. THE
CATCH HERE IS THAT THE SOUTHERN HALF OF THE FORECAST AREA...SOUTH
OF I-96 REMAINS ENTRENCHED IN THE WARM SECTOR AND COULD EXPERIENCE
HIGHER INSTANTANEOUS RAINFALL RATES. THIS MEANS THAT HEAVY RAINFALL
THAT DEVELOPS IN SOUTHERN SECTIONS OF THE FORECAST AREA...MAY
RESULT IN LOCALIZED HIGHER TOTALS...4-5 INCHES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...WDM
HYDROLOGY...JAM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
731 AM EDT TUE SEP 8 2015
.AVIATION...
SHOWERS WITH EMBEDDED THUNDER WILL PERSIST TO SOME DEGREE FOR
KFNT/KMBS THROUGH MUCH OF THE MORNING AND EARLY AFTN WITH A SLIGHT
INCREASE IN COVERAGE POSSIBLE WITH THE INTRODUCTION OF DIURNAL
HEATING. DETROIT AREA SITES ARE EXPECTED TO REMAIN LARGELY
DRY...THOUGH AN ISOLATED TSTORM CANNOT BE RULED OUT...UNTIL FROPA
LATE TONIGHT. SUFFICIENT DRY AIR NEAR THE SURFACE WILL SUSTAIN VFR
CONDITIONS AWAY FROM SHOWER ACTIVITY. IN AND NEAR SHOWERS...UPSTREAM
OBS HAVE SUGGESTED A HIGH PROBABILITY OF MVFR.
FOR DTW...CEILING DEVELOPMENT AROUND 5KFT WILL BE POSSIBLE FOR
MIXING UP TO 6KFT DURING THE AFTERNOON. A PARTIAL COVERAGE OF
SHOWERS...PERHAPS A TSTORM...WILL BE POSSIBLE DURING PEAK HEATING
BUT ATTM CONFIDENCE IN BOTH OCCURRENCE AND COVERAGE ARE TOO LOW TO
WARRANT A MENTION IN THE TAFS. SHOWERS WILL MOVE THROUGH LATE
TONIGHT BRINGING LOW MVFR TO IFR.
//DTW THRESHOLD PROBABILITIES...
* LOW FOR TSTORMS IMPACTING KDTW AIRSPACE
* MEDIUM FOR CIGS AOB 5KFT.
&&
.PREV DISCUSSION...ISSUED 340 AM EDT TUE SEP 8 2015
SHORT TERM...TODAY AND TONIGHT
ABSENT FORCING, THE RESERVOIR OF SIGNIFICANT MOISTURE ABOVE 700MB ON
LAST NIGHT`S 00Z DTX SOUNDING REMAINED QUIET THROUGH ABOUT 06Z.
HOWEVER, WARM ADVECTION WITHIN STRENGTHENING SWLY FLOW BEGAN TO
IGNITE CONVECTION ROUGHLY ALONG A CHICAGO TO PORT HURON LINE BY 07Z.
CONDITIONS WILL REMAIN FAVORABLE FOR EXPANSION OF THIS ACTIVITY
THROUGH THE MORNING AS FLOW CONTINUES TO INCREASE AND DAYTIME
HEATING ADDS A FEW HUNDRED J/KG CAPE TO THE PROFILE. THROUGH 18Z,
CONVECTION IS EXPECTED TO BE CONFINED MAINLY NORTH OF M59 ALONG WITH
THE BETTER FORCING. PWATS AROUND 2", LOW DENSITY CAPE, AND AN
INCREASINGLY DEEP WARM CLOUD LAYER WILL SUPPORT A HEAVY RAIN THREAT
FOR ANY AREAS THAT RECEIVE RAIN THROUGH TONIGHT. LOCALIZED FLOODING
IS NOT OUT OF THE QUESTION GIVEN SLOWER STORM MOTION AND THE
POTENTIAL FOR SOME AREAS ACROSS THE NORTHWEST TO SEE MULTIPLE ROUNDS
OF RAINFALL.
A SECOND AND STRONGER LLJ SURGE WILL ARRIVE BY AFTERNOON IN ADVANCE
OF THE SHORTWAVE NOTED OVER NORTHWEST MISSOURI AT 07Z THIS MORNING.
DYNAMIC FORCING WILL BE STOUT, BUT WILL ONLY OCCUR OVER A RELATIVELY
SMALL SPATIAL FOOTPRINT, MOST OF WHICH WILL BE OVER WESTERN AND
NORTHERN LOWER. HOWEVER, 06Z RAP INDICATES THAT THE CORE OF THE
ASSOCIATED 35-40KT LLJ WILL ALIGN ALONG A MUSKEGON TO WEST BRANCH
LINE 21-00Z WHICH WILL PUT THE SAGINAW VALLEY IN LINE TO RECEIVE A
NOTEWORTHY BOOST IN FORCING DUE TO DIFFERENTIAL WARM ADVECTION LATE
IN THE PEAK HEATING PERIOD. THUS, EVEN IF THE STRONGER DYNAMIC
FORCING DOES MANAGE TO MISS THE CWA...AND AT THIS TIME IT`S PROGGED
TO JUST GRAZE THE SAGINAW VALLEY AREA...NORTHWESTERN AREAS SHOULD
STILL SEE SOME EASTWARD EXPANSION OF CONVECTION DURING THE MID TO
LATE AFTERNOON DUE TO THE STRENGTHENING LLJ.
THE BULK OF THE RAIN SHIELD WILL EVENTUALLY PEEL NORTH ALONG WITH
THE DEPARTING WAVE, BUT LARGER SCALE FORCING EMBEDDED WITHIN THE
RIGHT ENTRANCE OF A 130KT UPPER JET OVER LAKE SUPERIOR WILL SUPPORT
A WAVE OF SHOWERS SLOWLY TRAVERSING THE REMAINDER OF THE AREA
ROUGHLY 00Z-12Z WED. THESE, TOO, WILL CARRY THE SAME THREAT FOR
HEAVY RAIN, THOUGH A DIMINISHED THREAT FOR FLOODING WILL EXIST DUE
TO INCREASINGLY PROGRESSIVE LARGER SCALE FORCING.
LONG TERM...
A STRONG WAVE ENTERING THE BASE OF THE MID/UPPER LEVEL TROUGH
CENTERED OVER WESTERN ONTARIO WILL PROVIDE THE NEEDED BOOST TO
USHER THE LINGERING FRONTAL BOUNDARY OFF TO THE EAST WEDNESDAY.
TIMING IS STILL NOT IRONED OUT EXACTLY AS THE INCOMING WESTERLY
JET MAX TURNS MORE NORTHEASTERLY ONCE IT PHASES WITH THE EXISTING
JET ALIGNED WITH THE FRONT. SO EXPECT THE FRONT TO BECOME MORE
PROGRESSIVE AS THE PARENT SYSTEM GAINS SPEED...BUT WITH THE SE
RIDGE STILL REACHING UP INTO THE EASTERN GREAT LAKES WE CAN EXPECT
SHOWERS TO LINGER OVER THE EASTERN COUNTIES INTO THE AFTERNOON
HOURS WEDNESDAY. THE FRONT WILL PUSH THE ENHANCED RIBBON OF
MOISTURE...NEAR 2 INCH PWATS...OFF TO THE EAST BY MIDDAY WEDNESDAY
BUT RESIDUAL MOISTURE POOL BETWEEN 1- 1.5 INCHES WILL STILL LINGER
THROUGH THE AFTERNOON UNTIL A SECONDARY TROUGH DROPS THROUGH LOWER
MI. THE NAM IS VERY BULLISH ON GENERATING SHOWERS WITH THIS
SECONDARY TROUGH IN PART DUE TO ELEVATED LL LAPSE RATES IN THE
WAKE OF THE FRONT. THERE IS SOME SIGNAL IN THE EURO/GFS BUT WITH
THE STRENGTH OF THE FRONTAL CIRCULATION...EXPECT A GOOD DEAL OF
SUBSIDENCE IN ITS WAKE COMBINED WITH THE BUILDING RIDGE. IN
ADDITION...THE NAM HAS BEEN DEVELOPING A SFC LOW ALONG THE FRONT
PASSING JUST TO OUR SOUTH THROUGH TOLEDO WEDNESDAY
AFTERNOON/EVENING. THIS WOULD RESULT IN ADDITIONAL DEFORMATION
FORCING LINGERING OVER SE MI AFTER 00Z THURSDAY. BUT AGAIN...NO
OTHER MODEL HAS ANYTHING NEARLY AS ORGANIZED AT THIS TIME.
SOMETHING TO WATCH BUT IN THE MEANTIME...FORECAST WILL FEATURE
CHANCE POPS DECREASING THROUGH THE DAY FROM NORTHWEST TO
SOUTHEAST.
WITH THE FRONT TO OUR SOUTH...PRECIP AND OVERCAST SKIES...HIGH
TEMPERATURES WILL TAKE A NOTABLE DIVE WEDNESDAY TOPPING OUT IN THE
UPPER 70S. THE SECONDARY TROUGH LATE WEDNESDAY WILL BRING ABOUT
COOLER WEATHER WITH NORTHERLY FLOW DROPPING HIGHS INTO THE MID 70S
FOR THURSDAY. TEMPS WILL TAKE A FURTHER NOSE DIVE INTO THE WEEKEND
AS YET ANOTHER FRONT SWEEPS THROUGH THE REGION ON FRIDAY BRINGING
THE NEXT CHANCE OF PRECIP WITH IT. MID MI MAY SEE SOME PRECIP
THURSDAY/THURSDAY NIGHT AS IT DRAPES SW TO NE THROUGH NORTHERN
LOWER...BUT MOST OF SE MI WILL REMAIN DRY TIL FRIDAY. MODELS DIVERGE
QUITE A BIT FOR THE WEEKEND IN THE HANDLING OF THIS NEXT UPPER
TROUGH...BUT CONSENSUS IS TROUGHING WILL HOLD OVER THE REGION WITH
ADDITIONAL SHOTS OF COOLER AIR WITH EACH FRONT. 850MB COLD POOL WILL
SET UP OVER THE GREAT LAKES WITH TEMPS POTENTIALLY DOWN INTO THE MID
SINGLE DIGITS AS HIGH PRESSURE SETTLES OVER THE REGION FROM CANADA.
MARINE...
A COLD FRONT DRAPED ACROSS THE CENTRAL GREAT LAKES IS RESULTING IN
WEAK FLOW WITHIN THE TROUGH OF LOW PRESSURE. THE EXCEPTION WOULD BE
LAKE ERIE AND LAKE ST CLAIR WHOM WILL CONTINUE TO RESIDE IN THE
SOUTHWESTERLY FLOW IN ADVANCE OF THE FRONT THROUGH THIS EVENING. THE
FRONT WILL BRING ABOUT A NOTABLE WIND SHIFT TONIGHT OVER LAKE HURON
TO NORTHWESTERLY...WHILE A TIGHTENED GRADIENT PROVIDES A BOOST TO
WIND SPEEDS WHICH WILL RANGE BETWEEN 20 AND 25 KNOTS POST COLD
FRONT. THIS FLOW WILL CONTINUE THROUGH WEDNESDAY AND WEDNESDAY NIGHT
AS A SECONDARY FRONT THEN DROPS THROUGH THE REGION. HIGH PRESSURE
WILL ALLOW WINDS TO RELAX ON THURSDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....JVC
SHORT TERM...JVC
LONG TERM....DRK
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
340 AM EDT TUE SEP 8 2015
.SHORT TERM...TODAY AND TONIGHT
ABSENT FORCING, THE RESERVOIR OF SIGNIFICANT MOISTURE ABOVE 700MB ON
LAST NIGHT`S 00Z DTX SOUNDING REMAINED QUIET THROUGH ABOUT 06Z.
HOWEVER, WARM ADVECTION WITHIN STRENGTHENING SWLY FLOW BEGAN TO
IGNITE CONVECTION ROUGHLY ALONG A CHICAGO TO PORT HURON LINE BY 07Z.
CONDITIONS WILL REMAIN FAVORABLE FOR EXPANSION OF THIS ACTIVITY
THROUGH THE MORNING AS FLOW CONTINUES TO INCREASE AND DAYTIME
HEATING ADDS A FEW HUNDRED J/KG CAPE TO THE PROFILE. THROUGH 18Z,
CONVECTION IS EXPECTED TO BE CONFINED MAINLY NORTH OF M59 ALONG WITH
THE BETTER FORCING. PWATS AROUND 2", LOW DENSITY CAPE, AND AN
INCREASINGLY DEEP WARM CLOUD LAYER WILL SUPPORT A HEAVY RAIN THREAT
FOR ANY AREAS THAT RECEIVE RAIN THROUGH TONIGHT. LOCALIZED FLOODING
IS NOT OUT OF THE QUESTION GIVEN SLOWER STORM MOTION AND THE
POTENTIAL FOR SOME AREAS ACROSS THE NORTHWEST TO SEE MULTIPLE ROUNDS
OF RAINFALL.
A SECOND AND STRONGER LLJ SURGE WILL ARRIVE BY AFTERNOON IN ADVANCE
OF THE SHORTWAVE NOTED OVER NORTHWEST MISSOURI AT 07Z THIS MORNING.
DYNAMIC FORCING WILL BE STOUT, BUT WILL ONLY OCCUR OVER A RELATIVELY
SMALL SPATIAL FOOTPRINT, MOST OF WHICH WILL BE OVER WESTERN AND
NORTHERN LOWER. HOWEVER, 06Z RAP INDICATES THAT THE CORE OF THE
ASSOCIATED 35-40KT LLJ WILL ALIGN ALONG A MUSKEGON TO WEST BRANCH
LINE 21-00Z WHICH WILL PUT THE SAGINAW VALLEY IN LINE TO RECEIVE A
NOTEWORTHY BOOST IN FORCING DUE TO DIFFERENTIAL WARM ADVECTION LATE
IN THE PEAK HEATING PERIOD. THUS, EVEN IF THE STRONGER DYNAMIC
FORCING DOES MANAGE TO MISS THE CWA...AND AT THIS TIME IT`S PROGGED
TO JUST GRAZE THE SAGINAW VALLEY AREA...NORTHWESTERN AREAS SHOULD
STILL SEE SOME EASTWARD EXPANSION OF CONVECTION DURING THE MID TO
LATE AFTERNOON DUE TO THE STRENGTHENING LLJ.
THE BULK OF THE RAIN SHIELD WILL EVENTUALLY PEEL NORTH ALONG WITH
THE DEPARTING WAVE, BUT LARGER SCALE FORCING EMBEDDED WITHIN THE
RIGHT ENTRANCE OF A 130KT UPPER JET OVER LAKE SUPERIOR WILL SUPPORT
A WAVE OF SHOWERS SLOWLY TRAVERSING THE REMAINDER OF THE AREA
ROUGHLY 00Z-12Z WED. THESE, TOO, WILL CARRY THE SAME THREAT FOR
HEAVY RAIN, THOUGH A DIMINISHED THREAT FOR FLOODING WILL EXIST DUE
TO INCREASINGLY PROGRESSIVE LARGER SCALE FORCING.
&&
.LONG TERM...
A STRONG WAVE ENTERING THE BASE OF THE MID/UPPER LEVEL TROUGH
CENTERED OVER WESTERN ONTARIO WILL PROVIDE THE NEEDED BOOST TO
USHER THE LINGERING FRONTAL BOUNDARY OFF TO THE EAST WEDNESDAY.
TIMING IS STILL NOT IRONED OUT EXACTLY AS THE INCOMING WESTERLY
JET MAX TURNS MORE NORTHEASTERLY ONCE IT PHASES WITH THE EXISTING
JET ALIGNED WITH THE FRONT. SO EXPECT THE FRONT TO BECOME MORE
PROGRESSIVE AS THE PARENT SYSTEM GAINS SPEED...BUT WITH THE SE
RIDGE STILL REACHING UP INTO THE EASTERN GREAT LAKES WE CAN EXPECT
SHOWERS TO LINGER OVER THE EASTERN COUNTIES INTO THE AFTERNOON
HOURS WEDNESDAY. THE FRONT WILL PUSH THE ENHANCED RIBBON OF
MOISTURE...NEAR 2 INCH PWATS...OFF TO THE EAST BY MIDDAY WEDNESDAY
BUT RESIDUAL MOISTURE POOL BETWEEN 1- 1.5 INCHES WILL STILL LINGER
THROUGH THE AFTERNOON UNTIL A SECONDARY TROUGH DROPS THROUGH LOWER
MI. THE NAM IS VERY BULLISH ON GENERATING SHOWERS WITH THIS
SECONDARY TROUGH IN PART DUE TO ELEVATED LL LAPSE RATES IN THE
WAKE OF THE FRONT. THERE IS SOME SIGNAL IN THE EURO/GFS BUT WITH
THE STRENGTH OF THE FRONTAL CIRCULATION...EXPECT A GOOD DEAL OF
SUBSIDENCE IN ITS WAKE COMBINED WITH THE BUILDING RIDGE. IN
ADDITION...THE NAM HAS BEEN DEVELOPING A SFC LOW ALONG THE FRONT
PASSING JUST TO OUR SOUTH THROUGH TOLEDO WEDNESDAY
AFTERNOON/EVENING. THIS WOULD RESULT IN ADDITIONAL DEFORMATION
FORCING LINGERING OVER SE MI AFTER 00Z THURSDAY. BUT AGAIN...NO
OTHER MODEL HAS ANYTHING NEARLY AS ORGANIZED AT THIS TIME.
SOMETHING TO WATCH BUT IN THE MEANTIME...FORECAST WILL FEATURE
CHANCE POPS DECREASING THROUGH THE DAY FROM NORTHWEST TO
SOUTHEAST.
WITH THE FRONT TO OUR SOUTH...PRECIP AND OVERCAST SKIES...HIGH
TEMPERATURES WILL TAKE A NOTABLE DIVE WEDNESDAY TOPPING OUT IN THE
UPPER 70S. THE SECONDARY TROUGH LATE WEDNESDAY WILL BRING ABOUT
COOLER WEATHER WITH NORTHERLY FLOW DROPPING HIGHS INTO THE MID 70S
FOR THURSDAY. TEMPS WILL TAKE A FURTHER NOSE DIVE INTO THE WEEKEND
AS YET ANOTHER FRONT SWEEPS THROUGH THE REGION ON FRIDAY BRINGING
THE NEXT CHANCE OF PRECIP WITH IT. MID MI MAY SEE SOME PRECIP
THURSDAY/THURSDAY NIGHT AS IT DRAPES SW TO NE THROUGH NORTHERN
LOWER...BUT MOST OF SE MI WILL REMAIN DRY TIL FRIDAY. MODELS DIVERGE
QUITE A BIT FOR THE WEEKEND IN THE HANDLING OF THIS NEXT UPPER
TROUGH...BUT CONSENSUS IS TROUGHING WILL HOLD OVER THE REGION WITH
ADDITIONAL SHOTS OF COOLER AIR WITH EACH FRONT. 850MB COLD POOL WILL
SET UP OVER THE GREAT LAKES WITH TEMPS POTENTIALLY DOWN INTO THE MID
SINGLE DIGITS AS HIGH PRESSURE SETTLES OVER THE REGION FROM CANADA.
&&
.MARINE...
A COLD FRONT DRAPED ACROSS THE CENTRAL GREAT LAKES IS RESULTING IN
WEAK FLOW WITHIN THE TROUGH OF LOW PRESSURE. THE EXCEPTION WOULD BE
LAKE ERIE AND LAKE ST CLAIR WHOM WILL CONTINUE TO RESIDE IN THE
SOUTHWESTERLY FLOW IN ADVANCE OF THE FRONT THROUGH THIS EVENING. THE
FRONT WILL BRING ABOUT A NOTABLE WIND SHIFT TONIGHT OVER LAKE HURON
TO NORTHWESTERLY...WHILE A TIGHTENED GRADIENT PROVIDES A BOOST TO
WIND SPEEDS WHICH WILL RANGE BETWEEN 20 AND 25 KNOTS POST COLD
FRONT. THIS FLOW WILL CONTINUE THROUGH WEDNESDAY AND WEDNESDAY NIGHT
AS A SECONDARY FRONT THEN DROPS THROUGH THE REGION. HIGH PRESSURE
WILL ALLOW WINDS TO RELAX ON THURSDAY.
&&
.AVIATION...ISSUED 1121 PM EDT MON SEP 7 2015
THE COLD FRONT HAS BASICALLY STALLED ACROSS NORTHERN LOWER AND
CENTRAL WI. THE FORECAST WILL START AS LOWER MI WILL BE IN A WINDOW
OF VERY LITTLE SHOWER ACTIVITY BEFORE THE NEXT WAVE AND JET ENERGY
STARTS TO KICK OFF SHOWERS AGAIN. DEW POINTS STILL AROUND 70 AND
JUST ENOUGH BREAKS AND THIN SPOTS TO HAVE MVFR FOG DEVELOP AGAIN.
COULD BECOME IFR WERE IT RAINED DURING THE EVENING. CEILINGS
OVERNIGHT SHOULD BE AOA 5000 FT.
THE NEXT WAVE STARTS BRING SHOWERS AND STORMS BACK TO MBS AROUND
DAYBREAK...THEN IN THE LATE MORNING TO EARLY AFTERNOON FOR FNT AND
PTK...BUT NOT UNTIL THE MID TO LATE AFTERNOON FOR THE DETROIT TAFS.
WITH THIS NEXT SURGE OF MOISTURE...EXPECT NUMEROUS
SHOWERS...EMBEDDED THUNDERSTORMS...MVFR CIGS AND VISIBILITIES WITH
SOME POTENTIAL FOR IFR VISIBILITIES WITH THE HEAVIEST OF THE RAIN.
FOR DTW...ENOUGH LOW LEVEL MOISTURE TO KEEP THE MVFR FOG FOR THE
EARLY PART OF THE TAF. NEXT THREAT OF RAIN WILL HOLD OFF UNTIL LATER
IN THE DAY ON TUESDAY. IN THE MEANTIME...SOME MOISTURE AROUND THE
5000 FT LEVEL WILL KEEP SCT TO BKN CLOUD COVER FOR MOST OF THE TAF
FORECAST.
FOR DTW...
//DTW THRESHOLD PROBABILITIES...
* LOW CONFIDENCE IN THUNDERSTORMS TUESDAY AFTERNOON.
* LOW CONFIDENCE IN CEILINGS AOB 5000 FEET.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...JVC
LONG TERM....DRK
MARINE.......DRK
AVIATION.....99
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
329 AM EDT TUE SEP 8 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/MARINE
.SYNOPSIS...
ISSUED AT 329 AM EDT TUE SEP 8 2015
PERIODS OF SHOWERS AND THUNDERSTORMS WILL PREVAIL TODAY INTO THIS
EVENING BEFORE A SLOW MOVING COLD FRONT PUSHES THEM SOUTH OF THE
AREA BY MID MORNING WEDNESDAY. AREAS OF LOCALIZED HEAVY RAINFALL
ARE POSSIBLE. IT WILL CONTINUE TO BE VERY HUMID TODAY BUT NOT
QUIET AS WARM AS THE PAST FEW DAY. COOLER AND SIGNIFICANTLY DRIER
AIR WILL FOLLOW THE COLD FRONT FOR WEDNESDAY AND SUNSHINE SHOULD
PREVAIL IN MOST AREAS BY MID AFTERNOON. A SECONDARY COLD FRONT
WILL COME THROUGH THE AREA ON FRIDAY WITH SCATTERED SHOWERS. THIS
COMING WEEKEND SHOULD BE MOSTLY CLEAR WITH MUCH COOLER
TEMPERATURES...HIGHS MAY ONLY REACH THE MID 60S ON SATURDAY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
OUR PRIMARY ISSUE CONTINUES TO BE THE THREAT FOR HEAVY RAINFALL.
PRECIPITABLE WATER CONTINUES TO RUN BETWEEN 1.8 AND 2.0 INCHES
OVER MOST OF THE CWA TODAY. THIS IS AROUND 3 TIMES NORMAL AND IS
APPROACHING ALL TIME RECORD VALUES FOR THIS TIME OF YEAR. ADD TO
THAT A FRONTAL BOUNDARY SLOWLY MOVING THROUGH THE AREA...AIDED BY
THE ENTRANCE REGION OF THE POLAR JET AND A SHORTWAVE FROM IOWA...
AND THERE IS LITTLE QUESTION SOME OF THE STORMS WILL PRODUCE
HEAVY RAINFALL. CORFIDI VECTORS WILL BE BELOW 10 MILE PER HOUR
THIS MORNING AND RISE TO AROUND 15 MPH THIS AFTERNOON. THAT TOO
WILL AID IN THE LOCALLY HEAVY RAINFALL. I STILL BELIEVE SOME
ISOLATED RAINFALL AMOUNTS MAY BE CLOSE TO 5 INCHES FROM THIS
EVENT.
WE HAVE THE REMAINS OF YESTERDAYS OUTFLOW BOUNDARY STALLED
BETWEEN I-94 AND I-96 EARLY THIS MORNING. AS THE SHORTWAVE FROM
IOWA MOVES CLOSER TO THIS AREA WILL BE THE FOCUS FOR CONVECTION
THIS MORNING. WHICH SUGGESTS THE STORMS WILL MOSTLY BE SOUTH OF
I-96 AT FIRST BUT THEN LIFT NORTHWARD WITH TIME. BY LATE MORNING
INTO EARLY AFTERNOON I WOULD EXPECT MOST OF THE CONVECTION TO BE
NORTH OF I-96. THEN AS THE PRIMARY COLD FRONT AND SHORTWAVE MOVE
INTO THE AREA.. THE RAP MODEL SHOWS A 30 - 35 KNOT LOW LEVEL JET
MOVING INTO THE AREA BY MID AFTERNOON. THE CORE OF THE SPEED MAX
WILL BE JUST NORTH OF I-96 AND BE EAST OF MKG BY 4 PM AND BE NORTH
OF LANSING BY 8 PM. THIS SUGGEST TO ME THE STRONGEST CONVECTION
WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING.
THERE IS A MARGINAL RISK FOR SEVERE STORMS (SPC) TODAY... WITH THE
NARROW CAPE... AND NUMEROUS HEAVY SHOWERS AROUND... AND ONLY
MARGINAL DEEP LAYER SHEAR... I WOULD IMAGINE ANY SEVERE WEATHER
WOULD BE VERY ISOLATED TODAY.
ONCE THE COLD FRONT COMES THROUGH MOST OF THE CONVECTION WILL EXIT
WITH IT THIS EVENING. HIGH PRESSURE FOLLOWS FOR WEDNESDAY INTO
THURSDAY. CLEARING SKIES FROM NORTHWEST TO SOUTHEAST WEDNESDAY
AFTERNOON. I WOULD EXPECT MOSTLY CLEAR SKIES WEDNESDAY NIGHT INTO
THURSDAY AS THE HIGH MOVES OVERHEAD.
BOTTOM LINE IS WET TODAY...DRY WEDNESDAY AFTERNOON INTO THURSDAY
EVENING.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
A NICE COOL DOWN IS EXPECTED BY THE END OF THE WEEK AS A DEEP UPPER
TROUGH DEVELOPS OVER THE GREAT LAKES. WE/LL SEE TEMPERATURES IN THE
60S FRIDAY THROUGH SUNDAY ALONG WITH SOME SHOWERS FRIDAY AND
SATURDAY. MODEL CONCERNS ARE SIMILAR TO YESTERDAY AS THE ECMWF
DEEPENS THE LOW AND THEN CUTS IT OFF OVER MICHIGAN SUNDAY WHILE THE
GFS KEEPS THE SYSTEM AN OPEN WAVE AND THEN SCOOTS IT EASTWARD BY
SUNDAY. THE GFS WOULD LEAD TO WARMER TEMPS AND LESS PCPN THAN THE
SLOWER COOLER ECMWF. WE/RE LEANING TOWARD THE GFS SOLUTION AS IT
ALSO LINES UP NICELY WITH THE LATEST FIM. THUS ANY SHOWERS SHOULD
END BY LATE SATURDAY LEADING TO DRY WX SUNDAY AND MONDAY AND WARMER
TEMPS AS RIDGING BUILDS INTO SW LWR MI.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 148 AM EDT TUE SEP 8 2015
SHOWERS ARE BEGINNING TO MOVE ACROSS SOUTHERN LOWER MICHIGAN
TOWARD THE SOUTHERN TAF SITES. NOT SEEING LIGHTNING YET IN IT BUT
THAT WILL LIKELY COME BY MID TO LATE MORNING AND THE AFTERNOON AS
A COLD FRONT SAGS ACROSS SW LWR MI. THE POTENTIAL EXIST LATER
TODAY FOR VSBYS TO FALL BELOW WHAT IS IN THE TAF IF A TSRA
DEVELOPS AT THE AIRPORT.
&&
.MARINE...
ISSUED AT 329 AM EDT TUE SEP 8 2015
WINDS AND WAVES SHOULD REMAIN BELOW SMALL CRAFT CRITERIA THROUGH
THURSDAY. EVEN SO THERE MAY BE GUSTY WINDS IN SOME OF THE
THUNDERSTORMS TODAY. VISIBILITIES MAY BE REDUCED TO BELOW A HALF
MILE IN SOME OF THE HEAVY THUNDERSTORMS TODAY.
&&
.HYDROLOGY...
ISSUED AT 1142 AM EDT MON SEP 7 2015
WE MAY RUN THE RISK FOR MINOR FLOODING BETWEEN LATE TONIGHT
THROUGH EARLY WEDNESDAY AS HEAVY RAIN IS POISED TO MARCH ACROSS
THE FORECAST AREA.
A SLOW MOVING FRONTAL BOUNDARY WILL BECOME NEARLY STATIONARY LATE
TONIGHT AND DURING THE DAY TUESDAY. FORECAST PRECIPITABLE WATER
VALUES OF AROUND 2.0 INCHES REMAINS UNCHANGED SINCE PRIOR
FORECASTS. TIMING SEEMS TO BE THE MOST CONSISTENT WITH THIS EVENT.
WHILE RAINFALL WILL BE POSSIBLE FROM TONIGHT THROUGH EARLY WEDNESDAY
AFTERNOON...THE HEAVIEST RAIN IS EXPECTED BETWEEN TUESDAY EVENING
AND WEDNESDAY MORNING.
THE ENTIRE FORECAST AREA CAN COUNT ON ABOUT AND INCH OF
PRECIPITATION...WHILE THE HEAVIEST SWATH LANDS NEAR AND NORTH OF
GRAND RAPIDS. 1-3 SEEMS REALISTIC ALONG AND NORTH OF I-96. THE
CATCH HERE IS THAT THE SOUTHERN HALF OF THE FORECAST AREA...SOUTH
OF I-96 REMAINS ENTRENCHED IN THE WARM SECTOR AND COULD EXPERIENCE
HIGHER INSTANTANEOUS RAINFALL RATES. THIS MEANS THAT HEAVY RAINFALL
THAT DEVELOPS IN SOUTHERN SECTIONS OF THE FORECAST AREA...MAY
RESULT IN LOCALIZED HIGHER TOTALS...4-5 INCHES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...04
HYDROLOGY...JAM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS DULUTH MN
1250 PM CDT TUE SEP 8 2015
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 331 AM CDT TUE SEP 8 2015
AT 330 AM...SKIES WERE PARTLY TO MOSTLY CLOUDY ACROSS THE
NORTHLAND. THERE WERE A FEW LIGHT RAIN SHOWERS OR SPRINKLES ACROSS
NW WI...WITH A LARGE AREA OF SHOWERS AND THUNDERSTORMS SOUTH AND
WEST OF THE CWA. TEMPERATURES RANGED FROM NEAR 50 ACROSS THE NORTH
TO THE LOWER 60S IN PORTIONS OF NW WI. WINDS WERE GENERALLY LIGHT.
THE MAIN FOCUS FOR TODAY WILL BE THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS...ESPECIALLY ACROSS NW WI. THE RAP SEEMS TO HAVE THE
BEST HANDLE ON THE CURRENT TRENDS ACROSS THE UPPER MIDWEST. HAVE
INCREASED POPS ACROSS NW WI THIS MORNING AND WILL HAVE TO KEEP A
CLOSE EYE ON THE CONVECTION STREAMING NORTHEAST FROM SOUTHERN MN.
MAY NEED TO INCREASE POPS EVEN FURTHER DEPENDING ON THE EVOLUTION
OF THE COMPLEX TO OUR SOUTH AS A SHORTWAVE LIFTS TO THE NORTH AND
EAST DURING THE MORNING. THE CHANCE OF PRECIPITATION WILL
GENERALLY INCREASE OVERNIGHT AND EARLY TODAY...AND THEN DECREASE
FROM LATE MORNING THROUGH THIS AFTERNOON. SKIES SHOULD BECOME
PARTLY TO MOSTLY SUNNY ACROSS THE AREA. HIGHS WILL BE IN THE 70S.
WITH CLEAR TO PARTLY CLOUDY SKIES AND HIGH PRESSURE SETTING IN
TONIGHT...WE SHOULD SEE OVERNIGHT LOWS LARGELY IN THE 40S.
WEST TO NORTHWEST FLOW ON WEDNESDAY WILL BRING A COUPLE AREAS OF
POSSIBLE PRECIPITATION AS THE DAY WEARS ON. THE FIRST WILL BE
ACROSS THE NORTH...AS A COLD FRONT DROPS SOUTHWARD ACROSS THE
INTERNATIONAL BORDER. ANOTHER WILL BE FURTHER SOUTH FROM EAST
CENTRAL MN INTO NORTHERN WISCONSIN...AS SHOWERS AND POSSIBLY EVEN
SOME THUNDERSTORMS DEVELOP IN THE AFTERNOON. THE COLD FRONT SHOULD
BE GENERALLY ACROSS THAT AREA BY LATE IN THE DAY. TEMPS WILL BE A
BIT COOLER ON WEDNESDAY...RANGING FROM THE MID 60S NORTH TO THE
LOWER TO MIDDLE 70S SOUTH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 331 AM CDT TUE SEP 8 2015
THE UPPER PATTERN WILL FEATURE AN UPPER LOW OVER HUDSON BAY EARLY IN
THE PERIOD WITH A TROUGH EXTENDING SOUTH INTO THE NORTHLAND. THE LOW
WILL MOVE EAST THROUGH THE PERIOD WITH NORTHWEST FLOW DEVELOPING.
FINALLY LATE IN THE WEEKEND/EARLY NEXT WEEK THE FLOW WILL BECOME
MORE ZONAL.
SEVERAL SHORTWAVES WILL MOVE THROUGH THE REGION BRINGING A CHANCE
FOR SHOWERS AND PERHAPS A THUNDERSTORM WEDNESDAY NIGHT THROUGH
FRIDAY AND AGAIN MONDAY/TUESDAY. AT THIS TIME...THESE SYSTEMS DO NOT
LOOK PARTICULARLY STRONG WITH THE EXCEPTION OF WEDNESDAY
NIGHT/THURSDAY. THE ECMWF IS SHOWING HIGHER RAINFALL OVER OUR
SOUTHERN ZONES WHICH IS NOT OUT OF THE QUESTION AS THERE SHOULD BE
SOME FGEN FORCING AS THE UPPER WAVE MOVES THROUGH. WE INCREASED POPS
OVER SOUTHERN AREAS A BIT...AND MAY HAVE TO INCREASE QUITE A BIT IF
BETTER AGREEMENT OCCURS AMONG THE MODELS.
TEMPERATURES WILL BE A FEW DEGREES COOLER THAN NORMAL
THURSDAY/FRIDAY/SATURDAY...THEN MODERATE BRIEFLY SUNDAY BEFORE
FALLING BELOW NORMAL AGAIN BY TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1226 PM CDT TUE SEP 8 2015
HIGH PRESSURE BUILDING IN FROM THE WEST WITH MUCH DRIER AIR WILL
ALLOW FOR GENERALLY VFR CONDITIONS THROUGH THE NEXT 24 HRS. A MID
LEVEL BAND OF CUMULUS WILL DEVELOP AND PASS THROUGH THIS
AFTERNOON AND EVENING...BUT WILL DISSIPATE THROUGH THE OVERNIGHT
AND LEAVE MOSTLY CLEAR SKIES THROUGH THE NIGHT. THE AIR MASS
SHOULD BE DRY ENOUGH AND WINDS WILL REMAIN VARIABLE AROUND 5
KTS...WHICH WILL KEEP WIDESPREAD FOG FROM FORMING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 74 49 71 50 / 10 0 20 20
INL 69 43 66 40 / 10 10 20 20
BRD 74 48 73 49 / 10 0 20 30
HYR 77 44 73 49 / 60 0 30 30
ASX 79 48 75 49 / 30 0 20 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM...MELDE
AVIATION...TENTINGER
AREA FORECAST DISCUSSION
NWS DULUTH MN
647 AM CDT TUE SEP 8 2015
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 331 AM CDT TUE SEP 8 2015
AT 330 AM...SKIES WERE PARTLY TO MOSTLY CLOUDY ACROSS THE
NORTHLAND. THERE WERE A FEW LIGHT RAIN SHOWERS OR SPRINKLES ACROSS
NW WI...WITH A LARGE AREA OF SHOWERS AND THUNDERSTORMS SOUTH AND
WEST OF THE CWA. TEMPERATURES RANGED FROM NEAR 50 ACROSS THE NORTH
TO THE LOWER 60S IN PORTIONS OF NW WI. WINDS WERE GENERALLY LIGHT.
THE MAIN FOCUS FOR TODAY WILL BE THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS...ESPECIALLY ACROSS NW WI. THE RAP SEEMS TO HAVE THE
BEST HANDLE ON THE CURRENT TRENDS ACROSS THE UPPER MIDWEST. HAVE
INCREASED POPS ACROSS NW WI THIS MORNING AND WILL HAVE TO KEEP A
CLOSE EYE ON THE CONVECTION STREAMING NORTHEAST FROM SOUTHERN MN.
MAY NEED TO INCREASE POPS EVEN FURTHER DEPENDING ON THE EVOLUTION
OF THE COMPLEX TO OUR SOUTH AS A SHORTWAVE LIFTS TO THE NORTH AND
EAST DURING THE MORNING. THE CHANCE OF PRECIPITATION WILL
GENERALLY INCREASE OVERNIGHT AND EARLY TODAY...AND THEN DECREASE
FROM LATE MORNING THROUGH THIS AFTERNOON. SKIES SHOULD BECOME
PARTLY TO MOSTLY SUNNY ACROSS THE AREA. HIGHS WILL BE IN THE 70S.
WITH CLEAR TO PARTLY CLOUDY SKIES AND HIGH PRESSURE SETTING IN
TONIGHT...WE SHOULD SEE OVERNIGHT LOWS LARGELY IN THE 40S.
WEST TO NORTHWEST FLOW ON WEDNESDAY WILL BRING A COUPLE AREAS OF
POSSIBLE PRECIPITATION AS THE DAY WEARS ON. THE FIRST WILL BE
ACROSS THE NORTH...AS A COLD FRONT DROPS SOUTHWARD ACROSS THE
INTERNATIONAL BORDER. ANOTHER WILL BE FURTHER SOUTH FROM EAST
CENTRAL MN INTO NORTHERN WISCONSIN...AS SHOWERS AND POSSIBLY EVEN
SOME THUNDERSTORMS DEVELOP IN THE AFTERNOON. THE COLD FRONT SHOULD
BE GENERALLY ACROSS THAT AREA BY LATE IN THE DAY. TEMPS WILL BE A
BIT COOLER ON WEDNESDAY...RANGING FROM THE MID 60S NORTH TO THE
LOWER TO MIDDLE 70S SOUTH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 331 AM CDT TUE SEP 8 2015
THE UPPER PATTERN WILL FEATURE AN UPPER LOW OVER HUDSON BAY EARLY IN
THE PERIOD WITH A TROUGH EXTENDING SOUTH INTO THE NORTHLAND. THE LOW
WILL MOVE EAST THROUGH THE PERIOD WITH NORTHWEST FLOW DEVELOPING.
FINALLY LATE IN THE WEEKEND/EARLY NEXT WEEK THE FLOW WILL BECOME
MORE ZONAL.
SEVERAL SHORTWAVES WILL MOVE THROUGH THE REGION BRINGING A CHANCE
FOR SHOWERS AND PERHAPS A THUNDERSTORM WEDNESDAY NIGHT THROUGH
FRIDAY AND AGAIN MONDAY/TUESDAY. AT THIS TIME...THESE SYSTEMS DO NOT
LOOK PARTICULARLY STRONG WITH THE EXCEPTION OF WEDNESDAY
NIGHT/THURSDAY. THE ECMWF IS SHOWING HIGHER RAINFALL OVER OUR
SOUTHERN ZONES WHICH IS NOT OUT OF THE QUESTION AS THERE SHOULD BE
SOME FGEN FORCING AS THE UPPER WAVE MOVES THROUGH. WE INCREASED POPS
OVER SOUTHERN AREAS A BIT...AND MAY HAVE TO INCREASE QUITE A BIT IF
BETTER AGREEMENT OCCURS AMONG THE MODELS.
TEMPERATURES WILL BE A FEW DEGREES COOLER THAN NORMAL
THURSDAY/FRIDAY/SATURDAY...THEN MODERATE BRIEFLY SUNDAY BEFORE
FALLING BELOW NORMAL AGAIN BY TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 638 AM CDT TUE SEP 8 2015
VFR CONDITIONS COVERED MUCH OF THE NORTHLAND...WITH SOME PATCHY
FOG PRODUCING IFR CONDITIONS. THE FOG WILL LIFT BETWEEN 8 AM AND
9 AM. LIGHT RAIN WAS FALLING OVER PORTIONS OF NORTHWEST WISCONSIN
WITH A FEW SPOTTY SHOWERS OVER PINE COUNTY. THE RAIN SHOULD BE
DIMINISHING THIS MORNING LEADING TO VFR CONDITIONS THROUGH THE
REST OF THE PERIOD.
GUSTY WEST/NORTHWEST WINDS WILL DEVELOP MOST AREAS LATE THIS
MORNING/EARLY AFTERNOON...THEN SUBSIDE EARLY THIS EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 74 49 71 50 / 10 0 20 20
INL 69 43 66 40 / 10 10 20 20
BRD 74 48 73 49 / 10 0 20 30
HYR 77 44 73 49 / 20 0 30 30
ASX 79 48 75 49 / 10 0 20 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM...MELDE
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS DULUTH MN
331 AM CDT TUE SEP 8 2015
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 331 AM CDT TUE SEP 8 2015
AT 330 AM...SKIES WERE PARTLY TO MOSTLY CLOUDY ACROSS THE
NORTHLAND. THERE WERE A FEW LIGHT RAIN SHOWERS OR SPRINKLES ACROSS
NW WI...WITH A LARGE AREA OF SHOWERS AND THUNDERSTORMS SOUTH AND
WEST OF THE CWA. TEMPERATURES RANGED FROM NEAR 50 ACROSS THE NORTH
TO THE LOWER 60S IN PORTIONS OF NW WI. WINDS WERE GENERALLY LIGHT.
THE MAIN FOCUS FOR TODAY WILL BE THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS...ESPECIALLY ACROSS NW WI. THE RAP SEEMS TO HAVE THE
BEST HANDLE ON THE CURRENT TRENDS ACROSS THE UPPER MIDWEST. HAVE
INCREASED POPS ACROSS NW WI THIS MORNING AND WILL HAVE TO KEEP A
CLOSE EYE ON THE CONVECTION STREAMING NORTHEAST FROM SOUTHERN MN.
MAY NEED TO INCREASE POPS EVEN FURTHER DEPENDING ON THE EVOLUTION
OF THE COMPLEX TO OUR SOUTH AS A SHORTWAVE LIFTS TO THE NORTH AND
EAST DURING THE MORNING. THE CHANCE OF PRECIPITATION WILL
GENERALLY INCREASE OVERNIGHT AND EARLY TODAY...AND THEN DECREASE
FROM LATE MORNING THROUGH THIS AFTERNOON. SKIES SHOULD BECOME
PARTLY TO MOSTLY SUNNY ACROSS THE AREA. HIGHS WILL BE IN THE 70S.
WITH CLEAR TO PARTLY CLOUDY SKIES AND HIGH PRESSURE SETTING IN
TONIGHT...WE SHOULD SEE OVERNIGHT LOWS LARGELY IN THE 40S.
WEST TO NORTHWEST FLOW ON WEDNESDAY WILL BRING A COUPLE AREAS OF
POSSIBLE PRECIPITATION AS THE DAY WEARS ON. THE FIRST WILL BE
ACROSS THE NORTH...AS A COLD FRONT DROPS SOUTHWARD ACROSS THE
INTERNATIONAL BORDER. ANOTHER WILL BE FURTHER SOUTH FROM EAST
CENTRAL MN INTO NORTHERN WISCONSIN...AS SHOWERS AND POSSIBLY EVEN
SOME THUNDERSTORMS DEVELOP IN THE AFTERNOON. THE COLD FRONT SHOULD
BE GENERALLY ACROSS THAT AREA BY LATE IN THE DAY. TEMPS WILL BE A
BIT COOLER ON WEDNESDAY...RANGING FROM THE MID 60S NORTH TO THE
LOWER TO MIDDLE 70S SOUTH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 331 AM CDT TUE SEP 8 2015
THE UPPER PATTERN WILL FEATURE AN UPPER LOW OVER HUDSON BAY EARLY IN
THE PERIOD WITH A TROUGH EXTENDING SOUTH INTO THE NORTHLAND. THE LOW
WILL MOVE EAST THROUGH THE PERIOD WITH NORTHWEST FLOW DEVELOPING.
FINALLY LATE IN THE WEEKEND/EARLY NEXT WEEK THE FLOW WILL BECOME
MORE ZONAL.
SEVERAL SHORTWAVES WILL MOVE THROUGH THE REGION BRINGING A CHANCE
FOR SHOWERS AND PERHAPS A THUNDERSTORM WEDNESDAY NIGHT THROUGH
FRIDAY AND AGAIN MONDAY/TUESDAY. AT THIS TIME...THESE SYSTEMS DO NOT
LOOK PARTICULARLY STRONG WITH THE EXCEPTION OF WEDNESDAY
NIGHT/THURSDAY. THE ECMWF IS SHOWING HIGHER RAINFALL OVER OUR
SOUTHERN ZONES WHICH IS NOT OUT OF THE QUESTION AS THERE SHOULD BE
SOME FGEN FORCING AS THE UPPER WAVE MOVES THROUGH. WE INCREASED POPS
OVER SOUTHERN AREAS A BIT...AND MAY HAVE TO INCREASE QUITE A BIT IF
BETTER AGREEMENT OCCURS AMONG THE MODELS.
TEMPERATURES WILL BE A FEW DEGREES COOLER THAN NORMAL
THURSDAY/FRIDAY/SATURDAY...THEN MODERATE BRIEFLY SUNDAY BEFORE
FALLING BELOW NORMAL AGAIN BY TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1148 PM CDT MON SEP 7 2015
UPPER LEVEL SHORT WAVES WILL PASS OVER THE TERMINALS THROUGH MID
MORNING. THESE SHORT WAVES WILL GENERATE CLOUD COVER AND A FEW
SHOWERS AFTER 15Z ALONG WITH GUSTY WINDS. VFR THROUGH THE
FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 74 49 71 50 / 10 0 20 20
INL 69 43 66 40 / 10 10 20 20
BRD 74 48 73 49 / 10 0 20 30
HYR 77 44 73 49 / 20 0 30 30
ASX 79 48 75 49 / 10 0 20 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM...MELDE
AVIATION...GSF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1001 AM CDT TUE SEP 8 2015
.UPDATE...DECIDED TO BRIDGE POPS ACROSS THE NULL AREA OVER THE CENTRAL
SECTIONS OF THE CWA FOR THIS AFTERNOON. DESPITE COLD CORE LOW OVER
THE NORTH CENTRAL GULF PULLING AWAY TO THE SW...DEEPER TROPICAL
MOISTURE FILLING IN FROM AL SHOULD BE SUFFICIENT FOR HEATING TO
SPECKLE IN SOME ISOLATED CONVECTION BY LATE AFTERNOON. THE HRRR HAS
A SCENARIO SIMILAR TO THIS AS WELL. TEMPS AND THE REST OF THE
FORECAST APPEARS ON TRACK./26/
&&
.AVIATION...VFR CONDITIONS WILL PREVAIL THROUGH WEDNESDAY. AFTN/EVNG
SHRA/TSRA COVERAGE WILL BE SPARSE AND IT IS VERY UNLIKELY THAT A TAF
SITE WILL BE IMPACTED. THERE WILL BE THE TYPICAL PATCHY AREAS OF
MVFR CATEGORY FOG DURING THE 09-14Z TIME FRAME...PARTICULARLY IN THE
HBG AREA. /EC/
&&
.PREV DISCUSSION... /ISSUED 436 AM CDT TUE SEP 8 2015/
SHORT TERM...TODAY THOUGH WEDNESDAY NIGHT...THE UPPER LOW IS
CURRENTLY SITUATED DIRECTLY SOUTH OF THE CWA ALONG THE GULF COAST
THIS MORNING WITH A SMALL SURFACE LOW PRODUCING CONVECTION JUST TO
THE EAST OF THAT OFF THE COAST OF THE FLORIDA PANHANDLE. THERE IS
QUITE THE MID LAYER SHEAR AXIS VISIBLE WHEN LOOKING AT THE VAD WINDS
THIS MORNING. A 60-70 KT JET APPEARS TO BE OVER THE CWA THIS MORNING
VIA OTHER UPPER AIR ANALYSIS. THE CONVERGENT LEFT ENTRANCE REGION OF
THIS FEATURE WILL BE THE FOCUS OF ANY AFTERNOON CONVECTION TODAY. THE
MAJORITY OF MODELS SHOW THIS CONVECTION REMAINING EAST OF OUR AREA.
THEREFORE POPS ARE RELATIVELY LOW TODAY EXCEPT FOR ALONG THE MS/AL
BORDER WHICH MAY SEE AN ISOLATED SHOWER/STORM THIS AFTERNOON. HIGH
TEMPERATURES WILL BE ABOVE NORMAL AGAIN AND VERY SIMILAR TO
YESTERDAY.
ON WEDNESDAY, AN UPPER TROUGH WILL BEGIN MAKING ITS WAY EAST. THE
ASSOCIATED FRONT WILL APPROACH THE AREA BUT DO NOT REALLY EXPECT IT
TO ENTER THE CWA UNTIL WEDNESDAY NIGHT/THURSDAY MORNING. WEDNESDAY
POPS WILL CONTINUE TO VARY BASED ON THE TIMING OF THIS FRONT. AS OF
NOW, AFTERNOON CONVECTION IS STILL EXPECTED OUT AHEAD OF THE FRONT
AND WILL BE FOCUSED MOSTLY EAST OF I-55. THE POTENTIAL FOR HAZARDOUS
WEATHER APPEARS TO PRETTY LOW FOR THIS TIMEFRAME FOR NOW. /10/
LONG TERM...THURSDAY THROUGH MONDAY...A COOLER AND WETTER START TO
THE LONG TERM PERIOD IS EXPECTED THURSDAY AS UPPER LEVEL TROUGHING
LINGERS OVER OUR REGION. THIS TROUGH WILL COMBINE WITH A MOIST AIR
MASS WITH A PWAT AROUND 2 INCHES AND DAYTIME HEATING TO RESULT IN
NUMEROUS STORMS. THE CLOUD COVER AND ASSOCIATED RAIN DEVELOPMENT
WILL HELP HOLD AFTERNOON HIGHS IN THE MID TO UPPER 80S OVER MOST OF
OUR AREA. NORMAL AFTERNOON HIGHS RUN IN THE UPPER 80S. MODELS AGREE
THAT ANOTHER MORE POTENT SHORTWAVE WILL BEGIN DEEPENING A BROAD
TROUGH OVER THE EASTERN CONUS FRIDAY INTO SATURDAY. THE GFS REMAINS
WEAKER WITH THE SHORTWAVE AND UPPER LEVEL TROUGH THAN THE CANADIAN
AND ECMWF WHICH CLOSE A LOW OFF OVER THE GREAT LAKES REGION BY
SATURDAY MORNING. DECENT RAIN CHANCES ARE EXPECTED FRIDAY AS THE
DEEPENING UPPER LEVEL TROUGH IS EXPECTED TO SUPPORT A COLD FRONT
THAT IS EXPECTED TO DROP INTO OUR CWA FRIDAY BUT SIDING WITH THE
ECMWF/CANADIAN...A DRIER WEEKEND LOOKS TO BE ON TAP. THE COLD FRONT
IS EXPECTED TO CLEAR OUR CWA SATURDAY AFTERNOON. A >1020MB SURFACE
HIGH WILL DROP OVER THE CENTRAL PLAINS AND HELP USHER IN A COOLER
AND DRIER AIR MASS INTO OUR CWA. DEW POINTS WILL DROP INTO THE 50S
WITH PWATS KNOCKED DOWN TO AROUND ONE INCH. UPPER LEVEL TROUGHING
WILL CONTINUE OVER OUR REGION THROUGH MONDAY BUT THE SURFACE HIGH
WILL REMAIN CENTERED NORTH OF OUR CWA AS IT TRACKS ACROSS THE
TENNESSEE AND OHIO VALLEYS BY MONDAY. THIS WILL KEEP THE GULF
CLOSED LIMITING CONVECTIVE POTENTIAL OVER OUR CWA. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 95 71 92 71 / 17 10 27 26
MERIDIAN 90 69 92 70 / 21 13 28 20
VICKSBURG 94 70 93 71 / 17 6 29 34
HATTIESBURG 92 71 92 71 / 25 16 27 17
NATCHEZ 93 71 92 71 / 21 9 23 28
GREENVILLE 95 72 91 72 / 9 9 37 47
GREENWOOD 94 71 92 71 / 13 7 33 43
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
26/EC
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
902 AM MDT TUE SEP 8 2015
.UPDATE...
A FEW CLOUDS WILL MOVE ACROSS THE FORECAST AREA TODAY.
OTHERWISE...SKIES WILL BE MOSTLY SUNNY WITH TEMPERATURES WARMING
CLOSE TO NORMAL FOR THIS TIME OF YEAR. PREVIOUS DISCUSSION AND
CURRENT FORECAST LOOKS TO BE IN GOOD SHAPE. THEREFORE...NO UPDATES
ARE PLANNED FOR TODAY. HOOLEY
&&
.SHORT TERM...VALID FOR TDY AND WED...
DRY AND SEASONABLY WARM WEATHER IS EXPECTED TODAY AND WEDNESDAY
WITH JUST A BIT OF AN AFTERNOON BREEZE IN MOST LOCATIONS.
AS OF 0830 UTC...LIGHT RAIN SHOWERS IN SOUTHEASTERN MT ASSOCIATED
WITH MODEST MID-LEVEL FRONTOGENESIS AND A PASSING SHORTWAVE TROUGH
ARE SHOWING SIGNS OF DECAY. TIME-LAGGED HRRR SIMULATIONS FROM BOTH
THE OPERATIONAL AND EXPERIMENTAL VERSION OF THE MODEL SUGGEST THAT
THESE SHOWERS WILL BE COMPLETELY GONE BY ABOUT 12 UTC AND THE REST
OF THE 00 UTC GUIDANCE AGREES...SO WE HAVE STARTED THE DAY WITH A
DRY FORECAST EVERYWHERE AFTER SUNRISE.
FOR TODAY...DRY NORTHWEST FLOW WILL PREVAIL ALOFT AND LOOKS DEVOID
OF ADDITIONAL SHORTWAVE TROUGHS OF ANY SIGNIFICANCE...SO WE EXPECT
A QUIET DAY. FORECAST SOUNDINGS SUPPORT MIXING TO ABOUT 650-MB IN
MOST AREAS AND WITH A BIT OF WARMING ALOFT HIGHS WILL TAKE A STEP
UPWARD FROM YESTERDAY...WITH FORECAST VALUES WELL INTO THE 70S F.
HUMIDITIES WILL FALL TO BETWEEN 15 AND 20 PERCENT IN SOUTH CENTRAL
MT AND PERHAPS NORTH CENTRAL WY THIS AFTERNOON...AND THERMAL GUSTS
TO 30 MPH ARE LIKELY IN THE LIVINGSTON AND BIG TIMBER AREAS DURING
PEAK HEATING WHEN THE BOUNDARY LAYER IS DEEPEST. THAT WILL PRODUCE
ELEVATED FIRE DANGER IN THAT AREA FOR A FEW HOURS THIS AFTERNOON.
TONIGHT...LOWS WILL BE IN THE 40S TO AROUND 50 F AS DRY NORTHWEST
FLOW CONTINUES ALOFT.
WEDNESDAY...THE 00 UTC GUIDANCE SHOWS A WEAK SURFACE LOW DROPPING
INTO ND DURING THE DAY...PLACING SOUTHERN MT AND NORTHERN WY IN
THE WARM SECTOR OF THAT FEATURE AHEAD OF A SOUTHWARD-MOVING COOL
FRONT. THIS SCENARIO WILL LIKELY ENHANCE THE EFFICIENCY OF LOW-
LEVEL TURBULENT MIXING...SO WE HAVE LEANED TOWARD THE WARMER SIDE
OF THE 00 UTC MODEL GUIDANCE FOR FORECAST HIGHS AROUND 80 F OVER
MOST OF THE AREA. WE LEFT A DRY FORECAST IN PLACE WEDNESDAY NIGHT
EVEN AS THE COOL FRONT SETTLES ACROSS THE AREA GIVEN THE LACK OF
APPRECIABLE FORCING ALOFT IN MOST 00 UTC MODEL SOLUTIONS. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
AN UPPER RIDGE GRADUALLY BUILDS INTO THE NORTHERN ROCKIES THROUGH
THE END OF THE WEEK UNDER WEAKENING NORTHWEST FLOW ALOFT. THIS
WILL KEEP THE FORECAST DRY AND PROMOTE WARMER TEMPERATURES INTO
THE EARLY PART OF THE WEEKEND. IN FACT...TEMPERATURES LOOK TO
APPROACH 90 DEGREES ON SATURDAY. MODELS LOWER HEIGHTS SOME SUNDAY
INTO MONDAY AS A COLD FRONT MOVES THROUGH. THIS FRONT IS PROGGED
WEAKER THAN THE LAST SEVERAL MODEL RUNS. GUIDANCE NOW ONLY LOWERS
HIGHS TO THE MID 70S ON MONDAY...WHICH ARE CLIMATE AVERAGES. HAVE
INCLUDED CHANCE POPS STARTING SUNDAY NIGHT WITH THE COLD FRONT AND
LINGERING THEM INTO EARLY NEXT WEEK WITH LOWERING HEIGHTS AND WEAK
ENERGY STREAMING IN FROM THE WEST.
IT SHOULD BE NOTED THAT BEYOND MONDAY...MODELS DIVERGE FOR THE
WEATHER PATTERN INTO THE MIDDLE OF NEXT WEEK. THE GFS WAS MORE
AGGRESSIVE ON A TROUGH SLIDING INTO MONTANA FROM THE NORTHWEST
PROVIDING A DECENT COOL DOWN. THE ECMWF WEAKENS THE TROUGH
TREMENDOUSLY OVER BRITISH COLUMBIA AND ACTUALLY DEVELOPS SOUTHWEST
FLOW OVER THE GREAT BASIN...FOR A MUCH WARMER REGIME. THE ECMWF
HAS NOT BEEN CONSISTENT OF LATE BEYOND 180 HOURS AND GREATLY
HESITATE FOLLOWING IT. THAT BEING SAID...THE GFS HAS BACKED OFF
QUITE A BIT ON THE DEPTH OF THE TROUGH FOR TUESDAY AS WELL.
INDICATIONS SEEM TO BE POINTING AWAY FROM A STRONG COOL DOWN NEXT
WEEK. WILL CONTINUE TO MONITOR. TWH
&&
.AVIATION...
VFR CONDITIONS ANTICIPATED TODAY. WEST TO NORTHWEST WINDS WILL
INCREASE THIS AFTERNOON AS THE DAY HEATS UP. SOME GUSTS TO 25 KTS
CAN BE EXPECTED AT KLVM WITH GUSTS NEAR 20 AND 15 KTS NEAR KBIL
AND KMLS...RESPECTIVELY. KSHR SHOULD REMAIN IN WEAK FLOW THROUGH
THE DAY. MROWELL
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 076 051/080 050/078 050/081 052/087 056/084 050/075
0/B 00/B 10/U 11/U 00/U 01/U 22/W
LVM 076 045/081 046/080 045/082 048/086 049/083 048/077
1/N 00/B 10/U 00/U 00/U 11/U 23/W
HDN 078 048/082 049/079 048/082 050/088 053/085 049/079
1/B 00/B 11/B 11/U 00/U 01/U 22/W
MLS 075 051/079 050/076 049/079 052/086 055/084 049/075
1/B 00/B 11/B 11/U 00/U 00/U 22/W
4BQ 074 050/079 051/076 049/079 051/085 054/086 052/077
1/B 00/B 11/B 00/B 00/U 00/U 22/W
BHK 073 048/077 047/072 045/076 048/082 051/082 049/072
1/B 00/B 11/B 11/B 00/U 00/U 22/W
SHR 077 044/081 046/079 045/083 046/085 049/085 048/080
1/U 00/B 11/B 11/U 00/U 01/U 22/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
246 AM MDT TUE SEP 8 2015
.SHORT TERM...VALID FOR TDY AND WED...
DRY AND SEASONABLY WARM WEATHER IS EXPECTED TODAY AND WEDNESDAY
WITH JUST A BIT OF AN AFTERNOON BREEZE IN MOST LOCATIONS.
AS OF 0830 UTC...LIGHT RAIN SHOWERS IN SOUTHEASTERN MT ASSOCIATED
WITH MODEST MID-LEVEL FRONTOGENESIS AND A PASSING SHORTWAVE TROUGH
ARE SHOWING SIGNS OF DECAY. TIME-LAGGED HRRR SIMULATIONS FROM BOTH
THE OPERATIONAL AND EXPERIMENTAL VERSION OF THE MODEL SUGGEST THAT
THESE SHOWERS WILL BE COMPLETELY GONE BY ABOUT 12 UTC AND THE REST
OF THE 00 UTC GUIDANCE AGREES...SO WE HAVE STARTED THE DAY WITH A
DRY FORECAST EVERYWHERE AFTER SUNRISE.
FOR TODAY...DRY NORTHWEST FLOW WILL PREVAIL ALOFT AND LOOKS DEVOID
OF ADDITIONAL SHORTWAVE TROUGHS OF ANY SIGNIFICANCE...SO WE EXPECT
A QUIET DAY. FORECAST SOUNDINGS SUPPORT MIXING TO ABOUT 650-MB IN
MOST AREAS AND WITH A BIT OF WARMING ALOFT HIGHS WILL TAKE A STEP
UPWARD FROM YESTERDAY...WITH FORECAST VALUES WELL INTO THE 70S F.
HUMIDITIES WILL FALL TO BETWEEN 15 AND 20 PERCENT IN SOUTH CENTRAL
MT AND PERHAPS NORTH CENTRAL WY THIS AFTERNOON...AND THERMAL GUSTS
TO 30 MPH ARE LIKELY IN THE LIVINGSTON AND BIG TIMBER AREAS DURING
PEAK HEATING WHEN THE BOUNDARY LAYER IS DEEPEST. THAT WILL PRODUCE
ELEVATED FIRE DANGER IN THAT AREA FOR A FEW HOURS THIS AFTERNOON.
TONIGHT...LOWS WILL BE IN THE 40S TO AROUND 50 F AS DRY NORTHWEST
FLOW CONTINUES ALOFT.
WEDNESDAY...THE 00 UTC GUIDANCE SHOWS A WEAK SURFACE LOW DROPPING
INTO ND DURING THE DAY...PLACING SOUTHERN MT AND NORTHERN WY IN
THE WARM SECTOR OF THAT FEATURE AHEAD OF A SOUTHWARD-MOVING COOL
FRONT. THIS SCENARIO WILL LIKELY ENHANCE THE EFFICIENCY OF LOW-
LEVEL TURBULENT MIXING...SO WE HAVE LEANED TOWARD THE WARMER SIDE
OF THE 00 UTC MODEL GUIDANCE FOR FORECAST HIGHS AROUND 80 F OVER
MOST OF THE AREA. WE LEFT A DRY FORECAST IN PLACE WEDNESDAY NIGHT
EVEN AS THE COOL FRONT SETTLES ACROSS THE AREA GIVEN THE LACK OF
APPRECIABLE FORCING ALOFT IN MOST 00 UTC MODEL SOLUTIONS. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
AN UPPER RIDGE GRADUALLY BUILDS INTO THE NORTHERN ROCKIES THROUGH
THE END OF THE WEEK UNDER WEAKENING NORTHWEST FLOW ALOFT. THIS
WILL KEEP THE FORECAST DRY AND PROMOTE WARMER TEMPERATURES INTO
THE EARLY PART OF THE WEEKEND. IN FACT...TEMPERATURES LOOK TO
APPROACH 90 DEGREES ON SATURDAY. MODELS LOWER HEIGHTS SOME SUNDAY
INTO MONDAY AS A COLD FRONT MOVES THROUGH. THIS FRONT IS PROGGED
WEAKER THAN THE LAST SEVERAL MODEL RUNS. GUIDANCE NOW ONLY LOWERS
HIGHS TO THE MID 70S ON MONDAY...WHICH ARE CLIMATE AVERAGES. HAVE
INCLUDED CHANCE POPS STARTING SUNDAY NIGHT WITH THE COLD FRONT AND
LINGERING THEM INTO EARLY NEXT WEEK WITH LOWERING HEIGHTS AND WEAK
ENERGY STREAMING IN FROM THE WEST.
IT SHOULD BE NOTED THAT BEYOND MONDAY...MODELS DIVERGE FOR THE
WEATHER PATTERN INTO THE MIDDLE OF NEXT WEEK. THE GFS WAS MORE
AGGRESSIVE ON A TROUGH SLIDING INTO MONTANA FROM THE NORTHWEST
PROVIDING A DECENT COOL DOWN. THE ECMWF WEAKENS THE TROUGH
TREMENDOUSLY OVER BRITISH COLUMBIA AND ACTUALLY DEVELOPS SOUTHWEST
FLOW OVER THE GREAT BASIN...FOR A MUCH WARMER REGIME. THE ECMWF
HAS NOT BEEN CONSISTENT OF LATE BEYOND 180 HOURS AND GREATLY
HESITATE FOLLOWING IT. THAT BEING SAID...THE GFS HAS BACKED OFF
QUITE A BIT ON THE DEPTH OF THE TROUGH FOR TUESDAY AS WELL.
INDICATIONS SEEM TO BE POINTING AWAY FROM A STRONG COOL DOWN NEXT
WEEK. WILL CONTINUE TO MONITOR. TWH
&&
.AVIATION...
CLOUDS WILL DECREASE FROM KBIL EASTWARD THIS MORNING AS A
DISTURBANCE EXISTS THE AREA. VFR FLYING WEATHER IS ANTICIPATED
TODAY. WEST TO NORTHWEST WINDS WILL INCREASE THIS AFTERNOON AS THE
DAY HEATS UP. SOME GUSTS TO 25 KTS CAN BE EXPECTED AT KLVM WITH
GUSTS NEAR 20KTS AT KMLS AND KBIL. TWH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 076 051/080 050/078 050/081 052/087 056/084 050/075
0/B 00/B 10/U 11/U 00/U 01/U 22/W
LVM 076 045/081 046/080 045/082 048/086 049/083 048/077
1/N 00/B 10/U 00/U 00/U 11/U 23/W
HDN 078 048/082 049/079 048/082 050/088 053/085 049/079
1/B 00/B 11/B 11/U 00/U 01/U 22/W
MLS 075 051/079 050/076 049/079 052/086 055/084 049/075
1/B 00/B 11/B 11/U 00/U 00/U 22/W
4BQ 074 050/079 051/076 049/079 051/085 054/086 052/077
1/B 00/B 11/B 00/B 00/U 00/U 22/W
BHK 073 048/077 047/072 045/076 048/082 051/082 049/072
1/B 00/B 11/B 11/B 00/U 00/U 22/W
SHR 077 044/081 046/079 045/083 046/085 049/085 048/080
1/U 00/B 11/B 11/U 00/U 01/U 22/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
644 PM CDT WED SEP 9 2015
.SYNOPSIS...
ISSUED AT 302 PM CDT WED SEP 9 2015
AS OF WEDNESDAY AFTERNOON THE UPPER AIR SYNOPTIC PATTERN OVER THE
CONTINUED TO BE HIGHLIGHTED BY A BROAD TROUGH ASSOCIATED WITH A LOW
SLOWLY MOVING TOWARD HUDSON BAY. THIS HAS THE NORTHERN AND CENTRAL
PLAINS IN RELATIVELY FAST NORTHWEST FLOW ALOFT. COOLER AIR IN THE
MID TO UPPER LEVEL OF THIS FLOW FOSTERED AN ENVIRONMENT
CHARACTERIZED BY STEEP LAPSE RATES AND ELEVATED INSTABILITY...WHICH
HAS AIDED IN THE FORMATION AND PERSISTENCE OF ISOLATED TO SCATTERED
THUNDERSTORM ACTIVITY IN CENTRAL NEBRASKA LATE IN THE MORNING AND
EARLY THIS AFTERNOON. AT THE SURFACE...A WEAK FRONT WAS SLOWLY
MOVING EAST ACROSS THE CWA. AS OF 20Z THE FRONT EXTENDED FROM JUST
EAST OF IMPERIAL AND NORTH PLATTE...NORTHEASTWARD TO NEAR AINSWORTH.
DRY WESTERLY WINDS BEHIND THE FRONT HAD DEWPOINTS DROPPING INTO THE
30S AND 40S ACROSS THE PANHANDLE AND WESTERN SANDHILLS. AHEAD OF
THE FRONT WINDS WERE SOUTHERLY AND DEWPOINTS REMAINED IN THE UPPER
50S AND 60S...WITH A CU FIELD DEVELOPING AS THE BOUNDARY LAYER
BECOMES MORE UNSTABLE. TEMPERATURES WERE GENERALLY IN THE MID 80S.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 302 PM CDT WED SEP 9 2015
THUNDERSTORMS IN CENTRAL AND NORTH CENTRAL NEBRASKA SHOULD CONTINUE
TO SLOWLY PUSH EAST THROUGH THE REMAINDER AFTERNOON. CONVECTIVE
ACTIVITY HAS ACCELERATED OVER CENTRAL ROCK AND HOLT COUNTY. SOME
LOCATIONS ARE RECEIVING HEAVY RAINFALL DUE TO TRAINING
STORMS...HOWEVER LATEST FFG IN THIS AREA IS QUITE HIGH. ADDITIONAL
SURFACE BASED SHOWERS AND THUNDERSTORM DEVELOPMENT HAS BEGUN IN FAR
SOUTHWEST NEBRASKA AND NORTHWEST KANSAS ALONG AN EASTWARD
PROGRESSING FRONT. HRRR HAS FAVORED AREAS JUST EAST OF A NORTH
PLATTE TO THEDFORD MUCH OF THE DAY...AND THIS MATCHES UP WELL WITH
THE DEVELOPING CU FIELD ON SATELLITE SO THE FORECAST LOOKS ON TRACK.
UPPER LEVEL FORCING IS TOUGH TO DISCERN SO THE SPATIAL EXTENT OF THE
NEW CONVECTION IS NOT EXPECTED TO BE EXPANSIVE. MLCAPE VALUES 1500
J/KG AND 35-40 KTS DEEP LAYER SHEAR WILL SUPPORT A FEW STRONG TO
SEVERE STORMS...HOWEVER WIDESPREAD SEVERE WEATHER IS NOT EXPECTED.
THUNDERSTORMS PUSH EAST THIS EVENING AND BEGIN TO WANE AFTER DARK
WITH THE LOSS OF HEATING AND INSTABILITY.
WEAK SHORTWAVE TROUGH DIVES SOUTHEAST THROUGH THE AREA OVERNIGHT.
WINDS BECOME EASTERLY AS THE FRONT SLOWLY PUSHES JUST SOUTHEAST OF
THE CWA AND A LEE SIDE SURFACE LOW DEEPENS IN NORTHEAST COLORADO.
THIS WILL ALLOW LOW LEVEL MOISTURE TO CREEP BACK WESTWARD...WITH
ANOTHER ROUND OF FOG/STRATUS POSSIBLE FOR SOUTHWEST INTO CENTRAL
NEBRASKA. DID NOT INCLUDE PATCHY FOG IN THE FORECAST AT THIS TIME
SINCE MODEL GUIDANCE HAS BEEN SOMEWHAT INCONSISTENT WITH COVERAGE
AND SEVERITY OF VISIBILITY RESTRICTIONS. THE MOST FAVORABLE AREAS
FOR LOCALLY DENSE FOG FORMATION WILL LIKELY BE WHERE PRECIPITATION
FALLS LATER THIS EVENING.
AN AREA OF SURFACE HIGH PRESSURE BEGINS TO DROP OUT OF ALBERTA AND
INTO THE NORTHERN PLAINS ON THURSDAY. THIS WILL PUSH TEMPERATURES
DOWN A FEW DEGREES WITH HIGHS RANGING FROM THE LOW 70S TO LOW 80S
ACROSS THE CWA. MODELS ADVERTISE LIGHT QPF LATE IN THE AFTERNOON AS
A MID-LEVEL JET STREAK NOSES INTO THE CENTRAL PLAINS...BUT DID NOT
ADD ANY MENTION OF POPS TO THE SHORT TERM FORECAST JUST YET AS THE
BETTER CHANCES LOOK TO BE AFTER 00Z FRIDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 302 PM CDT WED SEP 9 2015
THE NAM REMAINS IN AGREEMENT WITH CURRENT FORECAST WITH A
DISTURBANCE DROPPING SOUTHEAST FROM SWRN SD INTO WRN NEBR
OVERNIGHT. THE GFS IS FASTER WITH THIS DISTURBANCE AND REMAINS
MOSTLY DRY. THEREFORE KEPT POPS LIMITED TO 20 PERCENT WEST OF A
LINE FROM GORDON THROUGH BROKEN BOW.
KEPT VERY NEAR PREVIOUS HIGHS FRIDAY AS EASTERLY WINDS BECOME
SOUTHEAST BY AFTERNOON AND WEAK WAA WILL NOT KICK IN UNTIL
AFTERNOON. THERE COULD ALSO BE A FEW SHOWERS AND CLOUDINESS
LINGERING AS WELL.
ON SATURDAY...A RETURN SOUTHERLY WIND RETURNS WITH HIGHS WARMING
TO NEAR 80 ACROSS THE WEST WHILE THE EAST REMAINS IN THE LOWER TO
MID 70S.
FOR SUNDAY THROUGH TUESDAY...ABOVE NORMAL TEMPERATURES. ZONAL FLOW
ALOFT ACROSS THE CENTRAL PLAINS SUNDAY WILL PERSIST INTO MONDAY AS
AN UPPER TROUGH DIGS INTO THE PACIFIC NORTHWEST. THIS WILL KEEP A
THERMAL RIDGE ACROSS THE REGION WITH HIGHS RANGING IN THE 80S. ON
TUESDAY...THE UPPER TROUGH WILL ADVANCE ACROSS MONTANA THROUGH
COLORADO WITH STRONG HEATING TO OCCUR IN ADVANCE ACROSS THE
CENTRAL PLAINS. FORECAST HIGH ARE 85 TO 90...ALTHOUGH THE
POTENTIAL IS THERE FOR HIGHS TO EXCEED 90 IN SOME AREAS OF WRN
NEBR. A COLD FRONT TUESDAY NIGHT TO COOL BACK HIGHS TO NEAR 75
NORTH AND NEAR 80 SOUTH. THE 12Z ECMWF HOWEVER IS MUCH WEAKER WITH
THE POST FRONTAL COOLDOWN AND SUGGESTS 80S STILL POSSIBLE. MAINLY
DRY THROUGH THE EXTENDED PERIODS...EXCEPT A SLIGHT CHANCE ERN
PNHDL TUESDAY AFTN...AND MOST AREAS TUESDAY NIGHT. LOOKS DRY
BEHIND THE FRONT FOR WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 644 PM CDT WED SEP 9 2015
FOR THE KLBF TERMINAL...EXPECT SCATTERED TO BROKEN HIGH CLOUDS AON
20000 FT AGL OVER THE NEXT 24 HRS. FOR THE KVTN
TERMINAL...SCATTERED TO BROKEN CLOUDS AROUND 20000 FT AGL ARE
EXPECTED THROUGH LATE MORNING THURSDAY. BROKEN CIGS AROUND 10000
FT AGL ARE EXPECTED TO FORM THURSDAY AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MARTIN
SHORT TERM...MARTIN
LONG TERM...ROBERG
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
935 AM PDT TUE SEP 8 2015
.SYNOPSIS...HIGH PRESSURE ALOFT WILL BUILD NORTHWEST AND BECOME
CENTERED OVER THE MOJAVE DESERT THROUGH SATURDAY. THIS WILL RESULT
IN ABOVE NORMAL TEMPERATURES. MOIST AND UNSTABLE AIR WILL RESULT IN
THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS TODAY THROUGH THURSDAY
MAINLY IN THE AFTERNOON AND EVENING HOURS SOUTH OF INTERSTATE 40.
AFTER MAINLY DRY CONDITIONS ON FRIDAY AND SATURDAY AN AREA OF LOW
PRESSURE APPROACHING NORTHERN CALIFORNIA MAY SPARK OFF AN ISOLATED
SHOWER OR THUNDERSTORM ON SUNDAY IN THE HIGHER ELEVATIONS OF THE
MOJAVE DESERT.
&&
.UPDATE...CURRENT MESOANALYSIS INDICATED FAIRLY UNSTABLE AIR ACROSS
SOUTHEAST SAN BERNARDINO AND SOUTHERN MOHAVE COUNTIES AN ALSO NOSING
UP INTO NORTHERN MOHAVE COUNTY. THE LATEST NAM12 AND HRRR INDICATE
MOISTURE AND INSTABILITY PERSISTING ACROSS NORTHERN MOHAVE COUNTY
THIS AFTERNOON WHERE WE WERE NOT FORECASTING ANY THUNDERSTORMS. I
UPDATED TO INCREASE POPS AND MENTION THUNDERSTORMS IN THAT AREA FOR
THIS AFTERNOON AND EVENING. OTHERWISE THE FORECAST LOOKS GOOD AND NO
OTHER UPDATES ARE PLANNED. -HARRISON-
&&
.PREV DISCUSSION...
308 AM PDT TUE SEP 8 2015
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT.
FOR THE THIRD MORNING IN A ROW, A FEW SHOWERS AND THUNDERSTORMS HAVE
POPPED UP IN AN AREA OF MID-LEVEL CONVERGENCE BETWEEN THE WASHED OUT
MID/UPPER LEVEL TROUGH AXIS OVER SOUTHERN NEVADA AND THE EXIT REGION
OF A 250 MB JET STREAK LOCATED OVER ARIZONA AND SOUTHEAST
CALIFORNIA. THIS ACTIVITY WAS OVER THE PLATEAU REGION OF MOHAVE
COUNTY AS WELL AS IN THE JEAN/PRIMM/GOODSPRINGS AREA. THIS SHOULD
DIMINISH IN THE NEXT FEW HOURS.
HIGH PRESSURE ALOFT LOCATED NEAR EL PASO WILL BEGIN TO EXPAND
NORTHWEST TOWARD OUR AREA TODAY. THIS WILL RESULT IN ABOVE NORMAL
TEMPERATURES WITH READINGS JUMPING UP ANOTHER DEGREE OR TWO TODAY
FROM WHAT WAS OBSERVED ON LABOR DAY. THE EAST TO SOUTHEAST FLOW IN
THE MID-LEVELS AROUND THE HIGH WILL HELP TO SLOSH MOISTURE BACK TO
THE WEST TODAY. THE HRRR, ARW, NMM, WRF, GFS AND ECMWF ALL SHOW
SIMILAR TRENDS WITH THIS THOUGH VARY WIDELY WITH QPF DEVELOPMENT.
PWATS ACROSS THE MOJAVE DESERT WILL MAINLY BE BETWEEN 0.75 INCH AND
1.00 INCH. HOWEVER, A WARM LAYER ALOFT WILL KEEP MOST OF THE AREA
CAPPED AND THUS STABLE WITH THE RESULT JUST BEING CUMULUS. ALONG AND
SOUTH OF I-40 THE CAP MAY BE ABLE TO BREAK AND ALLOW FOR SHOWERS AND
THUNDERSTORMS TO GET GOING ESPECIALLY ONCE THE CONVECTIVE
TEMPERATURE OF 104 IS REACHED. THE 700 MB FLOW TODAY IS VARIABLE
ACROSS THE AREA SO STORMS WILL BE SLOWER MOVING COMPARED TO RECENT
DAYS. ONE AREA TO WATCH WILL BE IN SOUTHERN CLARK AND NORTHEAST SAN
BERNARDINO COUNTY WHERE THE STEERING FLOW IS WESTERLY AND WE MAY SEE
ACTIVITY MAKE A RUN TOWARD THE COLORADO RIVER VALLEY. THE HRRR AND
WRF ARE BOTH QUITE ACTIVE IN THIS AREA THIS AFTERNOON AS WELL AS IN
THE MORONGO BASIN. AS A RESULT, I INCREASED POPS ACROSS THE SOUTHERN
TIER OF THE AREA TODAY. THE MAIN THREATS WILL BE FLASH FLOODING WITH
ANY STRONGER OR SLOWER MOVING STORMS AS WELL AS GUSTY AND ERRATIC
WINDS AND BLOWING DUST.
THE ROUGH FIRE NEAR HUME LAKE, CA GREW IN SIZE YESTERDAY AND
VISIBILITY IN BISHOP WAS ALREADY BACK DOWN TO 6 MILES. THE WINDS
ALOFT ARE WEAKER IN THIS AREA BUT IF THE FIRE CRANKS UP AGAIN TODAY
WITH THE HEATING OF THE DAY, WE MAY AGAIN SEE EXTENSIVE SMOKE AND
HAZE INTO NORTHERN INYO COUNTY. THIS MAY STAY LOFTED DURING THE DAY
AS SURFACE WINDS PICK UP IN THE AFTERNOON BUT AS WINDS DROP OFF AT
NIGHT, THE SMOKE SHOULD SETTLE BACK DOWN AND DROP VISIBILITY ONCE
AGAIN.
THE AFOREMENTIONED HIGH IS SLATED TO BUILD NORTHWEST INTO THE MOJAVE
DESERT AND BECOME CENTERED OVERHEAD BY THURSDAY. THIS WILL TRAP
WHATEVER MOISTURE IS IN PLACE UNDERNEATH. FOR AREAS NORTH OF I-40,
WE SHOULD REMAIN CAPPED AND AT BEST SEE A FEW CUMULUS POP UP.
HOWEVER, ACROSS THE SOUTHERN TIER OF THE AREA, THE CAP WILL NOT BE
AS STRONG, AND SHOWERS AND THUNDERSTORMS WILL HAVE BETTER CHANCE TO
DEVELOP FROM THE MORONGO BASIN EAST TO WIKIEUP AND PERHAPS AS FAR
NORTH AS LUDLOW, THE MOJAVE NATIONAL PRESERVE, SEARCHLIGHT AND
KINGMAN. PWATS ARE SHOWN TO INCREASE TO NEAR 1.50 INCH BY WEDNESDAY
AND THURSDAY NEAR VIDAL JUNCTION AND LAKE HAVASU AS ADDITIONAL
MOISTURE GETS PUSHED NORTH FROM WHAT MAY BE A SURGE TRIGGERED BY
PACIFIC HURRICANE LINDA. THIS WILL INCREASE THE FLASH FLOOD THREAT
WITH STORMS AS THEY WILL HAVE A GREATER UNLOAD FACTOR. TEMPS WILL
TREND UP FURTHER IN AREAS FREE OF STORMS, HOWEVER, WHERE CLOUDS ARE
GREATER AND STORMS ARE AROUND TEMPS WILL ACTUALLY DROP A FEW
DEGREES. SMOKE ISSUES IN INYO COUNTY FROM THE ROUGH FIRE WILL NOT GO
AWAY EITHER AS THE WINDS ALOFT REMAIN WEAK AND MAY FAVOR MORE OF A
WESTERLY DIRECTION AGAIN BY THURSDAY.
.LONG TERM...FRIDAY THROUGH TUESDAY.
THE OVERALL PATTERN IS LOOKING SOMEWHAT INTERESTING THIS WEEKEND
INTO EARLY NEXT WEEK. FRIDAY STARTS OFF WITH A STRONG RIDGE CENTERED
ALMOST DIRECTLY OVER THE FORECAST AREA WHICH WILL PROVIDE HIGH TEMPS
OF 105-110 DEGREES OVER MUCH OF THE MOJAVE DESERT REGION.
MEANWHILE...REMNANT MOISTURE FROM LINDA IS FORECAST TO BE PULLED UP
ALONG THE CALIFORNIA COAST ON THE WEST SIDE OF THE RIDGE. THE LATEST
GFS AND ECMWF SOLUTIONS ARE IN GOOD AGREEMENT WITH NUDGING THE RIDGE
TO THE SOUTHEAST OVER ARIZONA SATURDAY INTO SUNDAY BY A WEAK LOW
PRESSURE SYSTEM MOVING INTO THE NORTHERN/CENTRAL CALIFORNIA COAST.
THIS LOW ALSO DIRECTS MOISTURE INLAND ACROSS SOUTHERN CALIFORNIA AND
THE MOJAVE DESERT REGION SUNDAY INTO MONDAY. SLIGHT CHANCE POPS
WHERE INTRODUCED TO THE HIGHER TERRAIN SUNDAY AS MOISTURE BEGINS TO
MOVE INTO THE FORECAST AREA.
THE LOW IS FORECAST TO CLOSE OFF AND CIRCULATE ALONG THE CENTRAL
CALIFORNIA COAST MONDAY WHICH WOULD LEAD TO DIFFLUENT FLOW COMBINING
WITH MODERATE MOISTURE AND INSTABILITY OVER SOUTHERN NEVADA AND
NORTHWEST ARIZONA FOR AT LEAST A SLIGHT CHANCE OF THUNDERSTORMS BY
MONDAY AFTERNOON. TEMPERATURES WILL ALSO TREND DOWNWARD SUNDAY
ONWARD WITH MORE CLOUD COVER AND THE INFLUENCE OF THE COASTAL LOW.
THE GFS AND ECMWF SOLUTIONS DIVERGE WITH RESPECT TO WHAT HAPPENS
WITH THE COASTAL LOW AFTER MONDAY AND CONFIDENCE IS LOW IN ANY
DETAILS AFTER THAT.
&&
.AVIATION...FOR MCCARRAN...WINDS WILL AGAIN FAVOR TYPICAL DIURNAL
TRENDS THROUGH TONIGHT. BETWEEN 15Z TODAY AND 00Z WEDNESDAY WINDS
WILL FAVOR AN EASTERLY COMPONENT INITIALLY FROM THE NORTHEAST THEN
MORE FROM THE SOUTHEAST AT 4-8 KTS WHICH MAY CAUSE CONFIGURATION
ISSUES. BY 04Z WEDNESDAY WINDS SHOULD MORE FIRMLY STAY OUT OF THE
SOUTH. FEW-SCT CLOUDS AOA 10K FEET.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WINDS WILL MAINLY FAVOR TYPICAL DIURNAL DIRECTIONS
THROUGH TONIGHT. ISOLATED SHRA/TSRA ARE POSSIBLE TODAY MAINLY AFTER
18Z ALONG AND SOUTH OF A LINE FROM ROUGHLY KNXP-KIFP-KIGM. GUSTY AND
ERRATIC WINDS ARE POSSIBLE IN AND NEAR ANY SHRA/TSRA. SCT-BKN CLOUDS
AOA 7K-12K FEET AS WELL ALONG AND SOUTH OF A LINE FROM KDAG-KHND-
KIGM. AREAS OF FU AND HZ ARE POSSIBLE IN AROUND KBIH REDUCING VSBY
AND CREATING LOCAL MOUNTAIN OBSCURATIONS.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...STACHELSKI
LONG TERM...ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
308 AM PDT TUE SEP 8 2015
.SYNOPSIS...HIGH PRESSURE ALOFT WILL BUILD NORTHWEST AND BECOME
CENTERED OVER THE MOJAVE DESERT THROUGH SATURDAY. THIS WILL RESULT
IN ABOVE NORMAL TEMPERATURES. MOIST AND UNSTABLE AIR WILL RESULT IN
THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS TODAY THROUGH THURSDAY
MAINLY IN THE AFTERNOON AND EVENING HOURS SOUTH OF INTERSTATE 40.
AFTER MAINLY DRY CONDITIONS ON FRIDAY AND SATURDAY AN AREA OF LOW
PRESSURE APPROACHING NORTHERN CALIFORNIA MAY SPARK OFF AN ISOLATED
SHOWER OR THUNDERSTORM ON SUNDAY IN THE HIGHER ELEVATIONS OF THE
MOJAVE DESERT.
&&
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT.
FOR THE THIRD MORNING IN A ROW, A FEW SHOWERS AND THUNDERSTORMS HAVE
POPPED UP IN AN AREA OF MID-LEVEL CONVERGENCE BETWEEN THE WASHED OUT
MID/UPPER LEVEL TROUGH AXIS OVER SOUTHERN NEVADA AND THE EXIT REGION
OF A 250 MB JET STREAK LOCATED OVER ARIZONA AND SOUTHEAST
CALIFORNIA. THIS ACTIVITY WAS OVER THE PLATEAU REGION OF MOHAVE
COUNTY AS WELL AS IN THE JEAN/PRIMM/GOODSPRINGS AREA. THIS SHOULD
DIMINISH IN THE NEXT FEW HOURS.
HIGH PRESSURE ALOFT LOCATED NEAR EL PASO WILL BEGIN TO EXPAND
NORTHWEST TOWARD OUR AREA TODAY. THIS WILL RESULT IN ABOVE NORMAL
TEMPERATURES WITH READINGS JUMPING UP ANOTHER DEGREE OR TWO TODAY
FROM WHAT WAS OBSERVED ON LABOR DAY. THE EAST TO SOUTHEAST FLOW IN
THE MID-LEVELS AROUND THE HIGH WILL HELP TO SLOSH MOISTURE BACK TO
THE WEST TODAY. THE HRRR, ARW, NMM, WRF, GFS AND ECMWF ALL SHOW
SIMILAR TRENDS WITH THIS THOUGH VARY WIDELY WITH QPF DEVELOPMENT.
PWATS ACROSS THE MOJAVE DESERT WILL MAINLY BE BETWEEN 0.75 INCH AND
1.00 INCH. HOWEVER, A WARM LAYER ALOFT WILL KEEP MOST OF THE AREA
CAPPED AND THUS STABLE WITH THE RESULT JUST BEING CUMULUS. ALONG AND
SOUTH OF I-40 THE CAP MAY BE ABLE TO BREAK AND ALLOW FOR SHOWERS AND
THUNDERSTORMS TO GET GOING ESPECIALLY ONCE THE CONVECTIVE
TEMPERATURE OF 104 IS REACHED. THE 700 MB FLOW TODAY IS VARIABLE
ACROSS THE AREA SO STORMS WILL BE SLOWER MOVING COMPARED TO RECENT
DAYS. ONE AREA TO WATCH WILL BE IN SOUTHERN CLARK AND NORTHEAST SAN
BERNARDINO COUNTY WHERE THE STEERING FLOW IS WESTERLY AND WE MAY SEE
ACTIVITY MAKE A RUN TOWARD THE COLORADO RIVER VALLEY. THE HRRR AND
WRF ARE BOTH QUITE ACTIVE IN THIS AREA THIS AFTERNOON AS WELL AS IN
THE MORONGO BASIN. AS A RESULT, I INCREASED POPS ACROSS THE SOUTHERN
TIER OF THE AREA TODAY. THE MAIN THREATS WILL BE FLASH FLOODING WITH
ANY STRONGER OR SLOWER MOVING STORMS AS WELL AS GUSTY AND ERRATIC
WINDS AND BLOWING DUST.
THE ROUGH FIRE NEAR HUME LAKE, CA GREW IN SIZE YESTERDAY AND
VISIBILITY IN BISHOP WAS ALREADY BACK DOWN TO 6 MILES. THE WINDS
ALOFT ARE WEAKER IN THIS AREA BUT IF THE FIRE CRANKS UP AGAIN TODAY
WITH THE HEATING OF THE DAY, WE MAY AGAIN SEE EXTENSIVE SMOKE AND
HAZE INTO NORTHERN INYO COUNTY. THIS MAY STAY LOFTED DURING THE DAY
AS SURFACE WINDS PICK UP IN THE AFTERNOON BUT AS WINDS DROP OFF AT
NIGHT, THE SMOKE SHOULD SETTLE BACK DOWN AND DROP VISIBILITY ONCE
AGAIN.
THE AFOREMENTIONED HIGH IS SLATED TO BUILD NORTHWEST INTO THE MOJAVE
DESERT AND BECOME CENTERED OVERHEAD BY THURSDAY. THIS WILL TRAP
WHATEVER MOISTURE IS IN PLACE UNDERNEATH. FOR AREAS NORTH OF I-40,
WE SHOULD REMAIN CAPPED AND AT BEST SEE A FEW CUMULUS POP UP.
HOWEVER, ACROSS THE SOUTHERN TIER OF THE AREA, THE CAP WILL NOT BE
AS STRONG, AND SHOWERS AND THUNDERSTORMS WILL HAVE BETTER CHANCE TO
DEVELOP FROM THE MORONGO BASIN EAST TO WIKIEUP AND PERHAPS AS FAR
NORTH AS LUDLOW, THE MOJAVE NATIONAL PRESERVE, SEARCHLIGHT AND
KINGMAN. PWATS ARE SHOWN TO INCREASE TO NEAR 1.50 INCH BY WEDNESDAY
AND THURSDAY NEAR VIDAL JUNCTION AND LAKE HAVASU AS ADDITIONAL
MOISTURE GETS PUSHED NORTH FROM WHAT MAY BE A SURGE TRIGGERED BY
PACIFIC HURRICANE LINDA. THIS WILL INCREASE THE FLASH FLOOD THREAT
WITH STORMS AS THEY WILL HAVE A GREATER UNLOAD FACTOR. TEMPS WILL
TREND UP FURTHER IN AREAS FREE OF STORMS, HOWEVER, WHERE CLOUDS ARE
GREATER AND STORMS ARE AROUND TEMPS WILL ACTUALLY DROP A FEW
DEGREES. SMOKE ISSUES IN INYO COUNTY FROM THE ROUGH FIRE WILL NOT GO
AWAY EITHER AS THE WINDS ALOFT REMAIN WEAK AND MAY FAVOR MORE OF A
WESTERLY DIRECTION AGAIN BY THURSDAY.
.LONG TERM...FRIDAY THROUGH TUESDAY.
THE OVERALL PATTERN IS LOOKING SOMEWHAT INTERESTING THIS WEEKEND
INTO EARLY NEXT WEEK. FRIDAY STARTS OFF WITH A STRONG RIDGE CENTERED
ALMOST DIRECTLY OVER THE FORECAST AREA WHICH WILL PROVIDE HIGH TEMPS
OF 105-110 DEGREES OVER MUCH OF THE MOJAVE DESERT REGION.
MEANWHILE...REMNANT MOISTURE FROM LINDA IS FORECAST TO BE PULLED UP
ALONG THE CALIFORNIA COAST ON THE WEST SIDE OF THE RIDGE. THE LATEST
GFS AND ECMWF SOLUTIONS ARE IN GOOD AGREEMENT WITH NUDGING THE RIDGE
TO THE SOUTHEAST OVER ARIZONA SATURDAY INTO SUNDAY BY A WEAK LOW
PRESSURE SYSTEM MOVING INTO THE NORTHERN/CENTRAL CALIFORNIA COAST.
THIS LOW ALSO DIRECTS MOISTURE INLAND ACROSS SOUTHERN CALIFORNIA AND
THE MOJAVE DESERT REGION SUNDAY INTO MONDAY. SLIGHT CHANCE POPS
WHERE INTRODUCED TO THE HIGHER TERRAIN SUNDAY AS MOISTURE BEGINS TO
MOVE INTO THE FORECAST AREA.
THE LOW IS FORECAST TO CLOSE OFF AND CIRCULATE ALONG THE CENTRAL
CALIFORNIA COAST MONDAY WHICH WOULD LEAD TO DIFFLUENT FLOW COMBINING
WITH MODERATE MOISTURE AND INSTABILITY OVER SOUTHERN NEVADA AND
NORTHWEST ARIZONA FOR AT LEAST A SLIGHT CHANCE OF THUNDERSTORMS BY
MONDAY AFTERNOON. TEMPERATURES WILL ALSO TREND DOWNWARD SUNDAY
ONWARD WITH MORE CLOUD COVER AND THE INFLUENCE OF THE COASTAL LOW.
THE GFS AND ECMWF SOLUTIONS DIVERGE WITH RESPECT TO WHAT HAPPENS
WITH THE COASTAL LOW AFTER MONDAY AND CONFIDENCE IS LOW IN ANY
DETAILS AFTER THAT.
&&
.AVIATION...FOR MCCARRAN...WINDS WILL AGAIN FAVOR TYPICAL DIURNAL
TRENDS THROUGH TONIGHT. BETWEEN 15Z TODAY AND 00Z WEDNESDAY WINDS
WILL FAVOR AN EASTERLY COMPONENT INITIALLY FROM THE NORTHEAST THEN
MORE FROM THE SOUTHEAST AT 4-8 KTS WHICH MAY CAUSE CONFIGURATION
ISSUES. BY 04Z WEDNESDAY WINDS SHOULD MORE FIRMLY STAY OUT OF THE
SOUTH. FEW-SCT CLOUDS AOA 10K FEET.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WINDS WILL MAINLY FAVOR TYPICAL DIURNAL DIRECTIONS
THROUGH TONIGHT. ISOLATED SHRA/TSRA ARE POSSIBLE TODAY MAINLY AFTER
18Z ALONG AND SOUTH OF A LINE FROM ROUGHLY KNXP-KIFP-KIGM. GUSTY AND
ERRATIC WINDS ARE POSSIBLE IN AND NEAR ANY SHRA/TSRA. SCT-BKN CLOUDS
AOA 7K-12K FEET AS WELL ALONG AND SOUTH OF A LINE FROM KDAG-KHND-
KIGM. AREAS OF FU AND HZ ARE POSSIBLE IN AROUND KBIH REDUCING VSBY
AND CREATING LOCAL MOUNTAIN OBSCURATIONS.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...STACHELSKI
LONG TERM...ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
553 PM MDT WED SEP 9 2015
.AVIATION...
00Z TAF CYCLE
-SHRA/-TS FAVORING THE CENTRAL MT CHAIN AND ADJACENT EASTERN
HIGHLANDS AND PLAINS...AS WELL AS NEW MEXICOS SOUTHERN HIGH
TERRAIN THIS EVENING. MOST OF THE ACTIVITY WILL DRIFT TO THE
SE AT 10 TO 15 MPH. THREAT FOR CONVECTION AND BRIEF HEAVY RAIN
AT KTCC AND KROW WILL CONTINUE FOR THE NEXT COUPLE OF HOURS WITH
MVFR TO BRIEF IFR CIGS AND VSBYS. OTHERWISE VFR CONDITIONS AT THE
REMAINING TAF SITES TONIGHT. LOW CLOUDS AND FOG NOT LIKELY TO
OCCUR TONIGHT AT KLVS...KTCC AND KROW. CROP OF SHOWERS AND STORMS
THURSDAY PM WILL BE LESS INTENSE AND COVERAGE WILL BE LESS.
&&
.PREV DISCUSSION...310 PM MDT WED SEP 9 2015...
.SYNOPSIS...
SCATTERED THUNDERSTORMS OVER CENTRAL NEW MEXICO WILL TAPER OFF THIS
EVENING. THE COVERAGE OF STORMS WILL FOCUS OVER SOUTHWEST NEW MEXICO
ON THURSDAY. DRIER AIR SETTLING INTO NORTHERN NEW MEXICO TONIGHT AND
THURSDAY NIGHT WILL ALLOW LOW TEMPERATURES TO SETTLE INTO THE 30S
AND 40S. A BACK DOOR COLD FRONT WILL SHIFT DOWN THE EASTERN PLAINS
ON FRIDAY ALLOWING FOR ANOTHER UPTICK IN STORMS. HIGH TEMPERATURES
WILL FALL BELOW NORMAL WITH MANY AREAS STAYING IN THE 70S. ISOLATED
STORMS ARE EXPECTED OVER THE WEEKEND BEFORE THE NEXT INCREASE IN
COVERAGE DEVELOPS MONDAY AND TUESDAY.
&&
.DISCUSSION...
THE COMBINATION OF A 40-50KT 300MB JET CORE AND MOIST UNSTABLE
UPSLOPE FLOW ALONG THE EAST SLOPES OF THE CENTRAL MT CHAIN TODAY
HAS LED TO A FEW STRONG TO LOCALLY SEVERE STORMS. SPC SSEO PICKED
UP ON THE COVERAGE AREA VERY WELL. HRRR AND LOCAL WRF SHOW THIS
ACTIVITY TAPERING OFF DURING THE EVENING WHILE DRYING TAKES PLACE
FROM NORTH TO SOUTH. SFC DEWPOINTS FROM THE NAM12 SHOW UPPER 20S/
LOW 30S TONIGHT ACROSS THE NW HALF OF THE STATE...WHICH COMBINED
WITH RADIATIONAL COOLING WILL LEAD TO CHILLY TEMPS. ANGEL FIRE IS
EXPECTED TO HIT FREEZING FOR THE 1ST TIME SINCE AUGUST 5TH.
THE AXIS FOR MOIST INSTABILITY WILL SHIFT FARTHER SOUTH THURSDAY
INTO SW NM WHILE DRY AIR ALOFT CONTINUES PRESSING S/SE OVER NORTHERN
NM. A FEW STORMS ARE STILL LIKELY AS WEAKLY FAVORABLE UPPER LEVEL
JET DYNAMICS DRIFT SOUTH OUT OF COLORADO. AT THE SURFACE THE FIRST
SIGNS OF A BACK DOOR FRONT WILL FLIRT WITH THE FAR NE PLAINS THUS
PROVIDING YET ANOTHER FORCING MECHANISM WITHIN COLFAX AND UNION
COUNTIES. THIS FRONT WILL SURGE INTO EASTERN NM AND THRU GAPS IN
THE CENTRAL MT CHAIN FRIDAY. MEANWHILE A 590DM H5 HIGH CENTER
WILL BECOME POSITIONED OVERHEAD AND FOCUS MORE TERRAIN DOMINATED
STORM COVERAGE FRIDAY THROUGH THE WEEKEND.
EXTENDED MODEL GUIDANCE IS GOING TO HAVE A DIFFICULT TIME WITH
THE REMNANTS OF HURRICANE LINDA NEXT WEEK AS SEVERAL DISORGANIZED
UPPER LEVEL VORT FEATURES TAKE SHAPE ALONG THE WEST COAST. FOR NOW
IT APPEARS MONDAY/TUESDAY COULD FEATURE AN UPTICK IN STORM
COVERAGE AS A PORTION OF THE 700-500MB MOISTURE AXIS CROSSES NM.
GUYER
&&
.FIRE WEATHER...
A NEW CENTROID OF HIGH PRESSURE HAS TAKEN SHAPE OVER THE GREAT
BASIN. THIS WILL FUNNEL DRIER AIR OVER NM FROM THE NORTHWEST WITH
MINIMUM HUMIDITIES FALLING A FEW TO 14 DEGREES ACROSS THE FORECAST
AREA THURSDAY. SINCE LOW LEVEL FLOW WILL ALSO TAKE ON MORE OF A
SOUTHWESTERLY COMPONENT ON THURSDAY...THERE WILL BE A DOWNTICK IN
SHOWER AND THUNDERSTORM COVERAGE WITH MAINLY ISOLATED ACTIVITY
FAVORING LOCATIONS ALONG AND EAST OF THE CONTINENTAL DIVIDE.
A STRONGER BACK DOOR COLD FRONT FRIDAY WILL BRING WITH IT MORE
MOISTURE WITH AN UPTICK IN SHOWER AND THUNDERSTORM ACTIVITY ALONG
AND EAST OF THE CENTRAL MOUNTAIN CHAIN DURING THE AFTERNOON...THEN
AS FAR WEST AS THE CONTINENTAL DIVIDE DURING THE EVENING. THIS FRONT
IS FORECAST TO PRODUCE A MODERATELY GUSTY EAST CANYON WIND IN THE
MIDDLE AND LOWER RIO GRANDE VALLEY FRIDAY AND FRIDAY NIGHT. ANOTHER
CROP OF THUNDERSTORMS IS EXPECTED ALONG AND EAST OF THE CONTINENTAL
DIVIDE ON SATURDAY AS MOISTURE RECYCLES...BUT THERE WILL BE A
DOWNTICK IN COVERAGE.
THE UPPER HIGH IS FORECAST TO MIGRATE SOUTHEASTWARD TO AROUND THE NM
BOOT HEEL ON SUNDAY...THEN TO THE SE OF NM ON MONDAY AS AN UPPER
LEVEL TROUGH DEEPENS INTO A LOW PRESSURE SYSTEM ON THE WEST COAST
AND EJECTS SOME OF ITS SHORTWAVE ENERGY INLAND ACROSS THE CENTRAL
ROCKIES. THERE ARE SIGNIFICANT DISAGREEMENTS BETWEEN MODELS ON THE
TRACK AND TIMING OF THIS LOW AND THE SHORTWAVES...BUT THE GFS AND
ECMWF DO AGREE FAIRLY WELL ON A TAP OF SUBTROPICAL MOISTURE IN
STRENGTHENING SW FLOW ALOFT REACHING SW AREAS SUNDAY AND MUCH OF
CENTRAL AND WESTERN NM MONDAY.
A ROLLER COASTER OF TEMPERATURES IS EXPECTED THROUGH THE WEEKEND.
HIGH TEMPERATURES WILL WARM A FEW TO 5 DEGREES THURSDAY...THEN FALL
WITH THE BACK DOOR COLD FRONT FRIDAY. FALLING TEMPERATURES WILL
CONTINUE IN THE WEST THROUGH SATURDAY...WHILE EASTERN READINGS BEGIN
TO REBOUND. HIGH TEMPS SHOULD THEN WARM SUNDAY AS THE CENTER OF HIGH
PRESSURE DRAWS NEAR...THEN BEGIN TO FALL IN THE WEST AGAIN MONDAY AS
BETTER MOISTURE ARRIVES. MINIMUM HUMIDITIES SHOULD FALL A FEW TO 22
PERCENT ON SUNDAY BEFORE BEGINNING TO REBOUND IN THE WEST ON MONDAY.
HIGH HAINES VALUES IN THE 5 TO 6 RANGE ARE EXPECTED OVER NORTHWEST
AND NORTH CENTRAL AREAS THURSDAY...THEN OVER NW AND WEST CENTRAL
AREAS FRIDAY. EXTREME VALUES SHOULD ABATE EAST OF THE CONTINENTAL
DIVIDE WITH THE ARRIVAL OF BETTER MOISTURE ON FRIDAY NIGHT AND
SATURDAY...ONLY TO OVERSPREAD MOST LOCATIONS ALONG AND NORTH OF
INTERSTATE 40 ON SUNDAY. NORTHEAST AREAS MAY CONTINUE TO BE
AFFLICTED WITH HIGH HAINES ON MONDAY.
POCKETS OF POOR VENTILATION WILL IMPACT WEST CENTRAL AREAS
WEDNESDAY...THEN NORTH CENTRAL...CENTRAL AND SOUTHWEST AREAS
THURSDAY. POCKETS OF POOR VENTILATION MAY LINGER INTO FRIDAY WEST
OF THE CONTINENTAL DIVIDE AND OVER THE SANGRE DE CRISTOS...BUT
VENTILATION LOOKS TO IMPROVE MOST PLACES SATURDAY AND ESPECIALLY
SUNDAY. RATES SHOULD THEN STAY GOOD TO EXCELLENT MONDAY. 44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1131 PM MDT MON SEP 7 2015
.AVIATION...
06Z TAF CYCLE
SCT SHOWERS WILL CONTINUE TO WEAKEN AND DIMINISH THROUGH THE
OVERNIGHT HOURS. VFR CONDITIONS SHOULD PREVAIL. TUESDAYS CROP
OF SHOWERS AND STORMS WILL BE LESS IN COVERAGE THAN TODAY...WITH
ISOL TO SCT CONVECTION FAVORING THE SOUTH AND EAST. CHJ
&&
.PREV DISCUSSION...302 PM MDT MON SEP 7 2015...
.SYNOPSIS...
STORMS WILL CONTINUE THIS EVENING LARGELY FOR AREAS SOUTH OF
INTERSTATE 40 WHERE SPOTTY LOCATIONS MAY SEE A HALF INCH OR MORE
OF RAIN. A BACK DOOR COLD FRONT WILL SLIDE DOWN THE PLAINS
TUESDAY AND TUESDAY NIGHT BEFORE PUSHING THROUGH THE GAPS OF THE
CENTRAL MOUNTAIN CHAIN WEDNESDAY MORNING. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE BEHIND THE FRONT ACROSS THE PLAINS.
TEMPERATURES WILL COOL IN THE WAKE OF THE FRONT...BUT WILL STILL
BE RIGHT AROUND NORMAL VALUES FOR EARLY SEPTEMBER WEDNESDAY
AFTERNOON. MID LEVEL DRY AIR WILL CONTINUE TO PUSH INTO THE STATE
ON THURSDAY AND FRIDAY...BUT ANOTHER BACK DOOR FRONT WILL BE
LURKING AS WELL.
&&
.DISCUSSION...
MOST OF THE RATHER WELL-BEHAVED STORMS TODAY HAVE STAYED SOUTH OF
I-40 AS EXPECTED. HRRR SUGGESTS THAT THE ABQ METRO AREA MAY SEE
SOME ACTION SHORTLY AFTER 00Z...BUT MOST OF THE ACTIVITY SHOULD
END BY MIDNIGHT ACROSS ALL AREAS.
STILL LOOKING FOR A BACK DOOR COLD FRONT TO MOVE INTO AT LEAST NE
NM ON TUESDAY BEFORE SLIDING SOUTH AND WEST TUESDAY NIGHT. THE
FRONT CONTINUES TO LOOK STRONGER WITH EACH MODEL RUN...AND A
BREEZY EAST CANYON WIND NOW LOOKS MORE LIKELY EARLY WEDNESDAY
MORNING FOR THE RIO GRANDE VALLEY. THE BIGGEST QUESTION CONTINUES
TO BE HOW MUCH PRECIPITATION WILL ACCOMPANY THE FRONT. GFS
CONTINUES TO BE VERY BULLISH BREAKING OUT STORMS ACROSS MUCH OF
EASTERN NM IN MOIST UPSLOPE FLOW TUESDAY NIGHT. OTHER MODELS ARE
LESS ENTHUSED. IT CERTAINLY SEEMS POSSIBLE SINCE MODELS ARE NOT
SHOWING AS MUCH DRYING AT MID LEVELS AS THEY WERE
YESTERDAY...EXCEPT FOR IN THE FAR NW. GIVING A NOD TO THE GFS
ENSEMBLE MEMBERS...WHICH ARE MUCH LIKE THEIR OPERATIONAL
COUNTERPART... BUMPED UP POPS A BIT MORE ACROSS THE EAST.
MOST MODELS NOW SHOWING CONVECTION ALONG THE CENTRAL MTN CHAIN ON
WEDNESDAY AFTERNOON WITH CONTINUED MOIST UPSLOPE FLOW. STORMS
SHOULD BE MORE ROBUST SOUTH OF I-40 WHERE MID LEVEL DRYING IS NOT
AS PREVALENT. HIGH TEMPERATURES ON WEDNESDAY SHOULD DROP AT LEAST
3 TO 8 DEGREES FROM TUESDAYS READINGS...THOUGH THIS WILL MEAN
TEMPS WILL ACTUALLY BE RIGHT AROUND NORMAL.
THE MID LEVEL DRY AIR NUDGES IN FARTHER ON THURSDAY...AND
CONVECTIVE COVERAGE SHOULD WANE A BIT. AREAS SOUTH OF HWY 60
SHOULD HAVE THE BEST STORM CHANCES. THEREAFTER...CONFIDENCE
REMAINS VERY LOW AS MODELS CONTINUE TO YO-YO THE NEXT BACK DOOR
FRONT AROUND. THE ECMWF IS BACK ON SCHEDULE FOR THE FRONT TO
ARRIVE ON FRIDAY...WHILE THE GFS IS AROUND 12 HOURS LATER AND ALSO
MUCH STRONGER. THIS WILL OBVIOUSLY HAVE SERIOUS IMPLICATION ON
POPS AND TEMPS...SO GENERALLY WENT FOR A MIDDLE OF THE ROAD
FORECAST FOR NOW.
34
&&
.FIRE WEATHER...
HIGH PRESSURE ALOFT IS FORECAST TO BUILD INTO THE GREAT BASIN THIS
WEEK...EVENTUALLY CUTTING OFF THE FLOW OF MOISTURE FROM THE
SOUTH...WHILE SHUNTING HURRICANE LINDA WEST OF BAJA CA/SOCAL. THIS
SHOULD LEAD TO A DRYING TREND FOR WESTERN NEW MEXICO. LOW LEVEL
MOISTURE WILL SLOSH BACK AND FORTH OVER CENTRAL AND EASTERN NEW
MEXICO THIS WEEK...DEPENDING ON TIMING OF 2 BOUNDARIES...ONE
EXPECTED TUESDAY/TUESDAY NIGHT AND A SECOND...WHICH THE GFS IS NOW
PORTRAYING AS STRONGER THAN IT HAS IN SEVERAL RUNS...ON
FRIDAY/FRIDAY NIGHT.
SO FAR THIS AFTERNOON...MOST OF THE CONVECTION HAS BEEN RELEGATED TO
AREAS ALONG AND SOUTH OF INTERSTATE 40...AS THE HRRR SUGGESTED.
WETTING RAIN FOOTPRINTS TO BE FAIRLY SMALL AS CELLS TRACK TO THE
EAST/NORTHEAST...AND ACTIVITY IS INDICATED TO DIMINISH BY MID
EVENING.
TUESDAY/WEDNESDAY ARE TRANSITION DAYS IN WHICH THE UPPER AIR PATTERN
SHIFTS FROM WEST TO NORTHWEST/NORTH WINDS ALOFT...IMPORTING
CONSIDERABLY DRIER AIR AT THE MID LEVELS. THE SURFACE BOUNDARY FOR
TUESDAY/TUESDAY NIGHT APPEARS A BIT MORE VIGOROUS AND MAY PUSH SOME
LOW LEVEL MOISTURE INTO THE RGV...WHICH MIXES OUT TO SOME EXTENT
WEDNESDAY...WHEN BEST CHANCES FOR WETTING RAIN WILL BECOME FOCUSED
ALONG THE CENTRAL MT CHAIN AND SOUTH OF I-40. PRECIPITATION CHANCES
TAPER DOWN THURSDAY INTO FRIDAY...BUT ANOTHER BOUNDARY COULD
REPLENISH LOW LEVEL MOISTURE INTO THE CENTRAL/EAST BY SATURDAY.
TOWARDS THE END OF THIS WEEK...AND INTO NEXT WEEK...FORECAST
VARIABLES CONTINUE TO BE QUITE VARIABLE WITH RUN TO RUN MODEL FLIP
FLOPPING. THE 12Z GFS DEVELOPS A VIGOROUS SHORT WAVE/CLOSED LOW ON
THE EASTERN PERIPHERY OF THE UPPER RIDGE OVER ERN NM/CHIHUAHUA THIS
WEEKEND THEN EJECTS IT NEWD EARLY NEXT WEEK. THE ECMWF HAS OTHER
IDEAS...MAINLY A 590 PLUS HIGH CENTER OVER NM. IN FACT...THE DEEP
UPPER TROF DEPICTED 24 HRS AGO BY BOTH NEAR 240 HRS HAS VANISHED.
KEEPING THE LOW CONFIDENCE IN MIND...HIGH HAINES WILL BE FOUND OVER
PORTIONS OF CENTRAL AND WRN NM MID TO LATE THIS WEEK. POOR OVERNIGHT
RECOVERIES WILL PLAGUE PORTIONS OF THE NW DURING THIS TIME...AND MIN
RH VALUES MAY FALL BELOW 15 PERCENT. HIGHS WILL BE CLOSE TO AVERAGE
FOR THE SEASON THROUGH THE UPCOMING WEEKEND. OVERNIGHT LOWS MAY FALL
TO NEAR FREEZING AT SOME OF THE NRN MT HIGHER TERRAIN OBS SITES MID
TO LATE WEEK. VENT RATES FORECAST TO BE GOOD TO EXCELLENT
TUESDAY...THEN DECREASE WEDNESDAY WITH AREAS OF FAIR TO POOR
FORECAST ALONG AND SOUTH OF I-40. WIDESPREAD FAIR TO POOR RATES
ANTICIPATED FRIDAY CENTRAL AND EAST.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
231 PM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC COAST WILL CONTINUE TO BRING
MIDSUMMERLIKE CONDITIONS TO THE REGION THROUGH THE FIRST HALF OF
WEDNESDAY...BEFORE A COLD FRONT CROSSES OUR REGION BETWEEN LATER
WEDNESDAY AND WEDNESDAY NIGHT. THIS FRONT WILL BE ACCOMPANIED BY
NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES THROUGH...AND WILL
BE FOLLOWED BY PROGRESSIVELY COOLER WEATHER DURING THE REMAINDER
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
DURING THE COURSE OF TODAY...THE WEAK COLD FRONT WILL BRIEFLY STALL
OUT ALONG OR SLIGHTLY NORTH OF OUR NORTHERN PERIPHERY THIS
MORNING... BEFORE LIFTING BACK NORTH THIS AFTERNOON AS A WARM FRONT
IN RESPONSE TO THE DEVELOPMENT OF BROAD LOW PRESSURE OVER THE UPPER
GREAT LAKES. ALONG AND NEAR THIS BOUNDARY...THERE WILL BE A
CONTINUED RISK OF SHOWERS AND THUNDERSTORMS THROUGH THE DAY...WITH
THIS RISK LYING ROUGHLY FROM THE NYS THRUWAY CORRIDOR NORTHWARD
THROUGH LATE THIS MORNING...THEN DIMINISHING FROM SOUTHWEST TO
NORTHEAST LATE THIS MORNING AND THIS AFTERNOON AS THE FRONT BEGINS
LIFTING BACK NORTH.
IN ADDITION TO ANY FRONTAL CONVECTION...THE COMBINATION OF DIURNAL
HEATING OF OUR VERY WARM AND HUMID AIRMASS AND REDEVELOPING LAKE
BREEZE BOUNDARIES MAY ALSO LEAD TO THE DEVELOPMENT OF A SECOND
REGION OF ISOLATED TO SCATTERED CONVECTION ACROSS AREAS SOUTH OF
LAKE ONTARIO THIS AFTERNOON...WITH THIS PRIMARILY FOCUSED FROM
INTERIOR PORTIONS OF THE SOUTHERN TIER AND GENESEE VALLEY EASTWARD
ACROSS THE FINGER LAKES.
WITH ALL OF THE ABOVE IN MIND...HAVE CONTINUED TO DEPICT A GENERAL
SOUTHWEST-NORTHEAST GRADIENT IN PRECIPITATION PROBABILITIES FOR
TODAY...WITH THESE RANGING FROM HIGH CHANCE TO LOW LIKELY FROM
LAKE ONTARIO EASTWARD ACROSS THE SAINT LAWRENCE VALLEY AND NORTH
COUNTRY...TO BELOW SLIGHT CHANCE IN AN EXPECTED REGION OF LAKE
SHADOWING IMMEDIATELY EAST OF LAKE ERIE.
OUTSIDE OF THE AFOREMENTIONED CONVECTION...DRY WEATHER AND
MIDSUMMERLIKE WARMTH AND HUMIDITY SHOULD AGAIN PREVAIL ACROSS OUR
REGION TODAY. SURFACE DEWPOINTS WILL RANGE FROM THE LOWER 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO NEAR 70 ALONG
THE STALLED/RETREATING FRONTAL BOUNDARY...WHILE 850 MB TEMPS OF
+16C TO +19C WILL SUPPORT HIGH TEMPERATURES RANGING FROM THE LOWER
80S ACROSS THE NORTH COUNTRY TO THE MID AND UPPER 80S ACROSS MOST
OF THE REST OF THE REGION...ALONG WITH SOME 90 DEGREE READINGS
ACROSS THE NORMAL WARM SPOTS OF THE GENESEE VALLEY/FINGER LAKES.
TONIGHT...THE WARM FRONT WILL FINISH LIFTING OFF TO OUR NORTH EARLY
IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE LOSS
OF DAYTIME HEATING...ANY LINGERING CONVECTION ACROSS THE FINGER LAKES
AND NORTH COUNTRY WILL COME TO AN END THIS EVENING...LEAVING BEHIND
LARGELY DRY WEATHER FOR THE BALANCE OF THE NIGHTTIME HOURS AS OUR
REGION WILL BE FIRMLY ENTRENCHED WITHIN THE WARM SECTOR OF LOW
PRESSURE LIFTING BY WELL TO OUR NORTHWEST. THUS...WE CAN EXPECT YET
ANOTHER UNSEASONABLY WARM NIGHT ACROSS OUR REGION...WITH OVERNIGHT
LOWS AGAIN RANGING FROM THE MID 60S ACROSS INTERIOR PORTIONS OF THE
SOUTHERN TIER TO THE LOWER 70S ACROSS THE LAKE PLAINS...OR LEVELS
THAT WILL BE NOT THAT FAR OFF FROM NORMAL HIGH TEMPERATURES FOR
EARLY SEPTEMBER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TEMPERATURES WILL RETURN TO NEAR NORMAL LEVELS ACROSS THE LOWER
GREAT LAKES DURING THIS PERIOD...AS THE UPPER LEVEL FLOW ACROSS
NORTH AMERICA WILL FEATURE AN AMPLIFYING TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS WILL BE SIGNIFICANT CHANGE FROM THE
FIRST WEEK OF SEPTEMBER WHEN A PERSISTENT SUB-TROPICAL RIDGE
DOMINATED THE EASTERN HALF OF THE COUNTRY. WHILE THE RIDGE WAS NOT
OVERLY IMPRESSIVE `ON PAPER`...ITS STAYING POWER FOR THIS TIME OF
YEAR ALLOWED FOR ANOMALOUSLY WARM AIR AND PLENTY OF GULF HUMIDITY
TO CREATE THE WARMEST STRETCH OF WEATHER OUR REGION EXPERIENCED
ALL SUMMER. WITH THE PASSING OF THE LAST SUMMER HOLIDAY...MOTHER
NATURE WILL ALSO TURN THE PAGE...ALBEIT IT SLOWLY.
AS IS SO OFTEN IS THE CASE...A STRONG LATITUDINAL H25 JET
CROSSING THE NORTHERN PACIFIC WILL PLOW ACROSS THE CANADIAN
ROCKIES AND ESTABLISH A BROAD DOWNSTREAM TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS TROUGH WILL FLATTEN THE PERTINACIOUS
SUB TROPICAL RIDGE...AND IN TIME WILL DIRECT PROGRESSIVELY COOLER
CANADIAN AIR SOUTHWARDS ACROSS THE LOWER 48. THIS COOLING WILL
INITIALLY ONLY TAKE OUR TEMPERATURES BACK TOWARDS NORMAL...BUT AS
WE HEAD IN TO THE WEEKEND...WE COULD EXPERIENCE A DAY OR TWO OF
FALL LIKE CONDITIONS.
AN INVERTED SFC TROUGH EXTENDING FROM THE UPPER GREAT LAKES TO
THE CENTRAL PLAINS LATE TUESDAY NIGHT WILL GRADUALLY EVOLVE INTO A
LEGITIMATE...ALBEIT WAVY...COLD FRONT ON WEDNESDAY AS IT WILL PUSH
SOUTHEAST ACROSS THE LOWER GREAT LAKES. THE OVERALL SYNOPTIC
FORCING WITH THE SLOW MOVING FRONTAL BOUNDARY IS NOT BEING
ADVERTISED AS BEING ALL THAT IMPRESSIVE...BUT IT WILL BE ENOUGH IN
COMBINATION WITH THE MID SUMMER LIKE THERMODYNAMIC ENVIRONMENT TO
PRODUCE INCREASINGLY NUMEROUS SHOWERS AND POTENTIALLY STRONG
THUNDERSTORMS.
ADDRESSING THE FORMER FIRST...AS EARLIER MENTIONED THE FRONTAL
BOUNDARY WILL STILL BE TAKING SHAPE DURING THE DAY WEDNESDAY AS IT
WILL BE PUSHING INTO OUR FORECAST AREA. TRUE FRONTOGENETIC FORCING
FROM THE FRONT WILL THUS BE GENERALLY WEAK...ALTHOUGH HGT FALLS
AND A 120KT H25 JET OVER NORTHERN QUEBEC WILL ADD SOME LARGE SCALE
SYNOPTIC LIFT BY PLACING OUR FORECAST AREA UNDER RR QUAD OF THE
JET ENTRANCE REGION. THERMODYNAMICALLY...OUR WARM HUMID AIRMASS
WILL ALREADY BE UNSTABLE. SBCAPES WILL ALREADY BE IN THE HUNDREDS
AS WE OPEN THE DAY...AND DIMINISHING MORNING SUNSHINE WILL ONLY
ADD TO THIS INSTABILITY...PARTICULARLY OVER PARTS OF THE SRN TIER
AND FINGER LAKES REGIONS WHERE MUCAPES COULD APPROACH 2000 J/KG.
MEANWHILE A SWATH OF TROPICAL MOISTURE TO THE TUNE OF 2 INCH PWAT
VALUES WILL STREAM ACROSS OUR REGION ALONG AND AHEAD OF THE SFC
BOUNDARY...SO THIS IN COMBINATION WITH THE SYNOPTIC FORCING AND
INSTABILITY COULD RESULT IN TORRENTIAL DOWNPOURS WITH SOME OF THE
CONVECTION. FORTUNATELY...THE REGION IS PARCHED FROM A GENERAL
LACK OF RAINFALL FROM THE PAST MONTH OR SO...AND GUIDANCE IS
SUGGESTING THAT CORFIDI VECTORS WILL LENGTHEN AS THE FRONT
APPROACHES. THIS WILL LESSEN THE RISK FOR WIDESPREAD HYDRO RELATED
PROBLEMS...BUT LOCAL ISSUES WILL STILL HAVE TO BE ADDRESSED GIVEN
THE SUB TROPICAL ENVIRONMENT. THE MENTION OF TORRENTIAL DOWNPOURS
HAS ALREADY BEEN ADDED TO THE HWO PRODUCT AND TO THE GRIDDED DATA
BASE...SO WILL CONTINUE.
ALONG WITH THE THREAT FOR LOCALLY HEAVY CONVECTIVE RAINS...THERE
WILL BE AN ISOLATED RISK FOR STRONG THUNDERSTORMS. THIS POTENTIAL
WILL BE ATTENUATED BY UNIMPRESSIVE MID LEVEL LAPSE RATES UNDER 6
DEG C/KM...BUT GIVEN BULK SHEAR VALUES OF 35 TO 40 KNOTS AND THE
UNCERTAINTY AS TO HOW MUCH SUNSHINE PARTS OF THE REGION RECEIVE...
WE WILL CONTINUE TO HIGHLIGHT THE CHANCE FOR GUSTY CONVECTIVE
WINDS.
CONSIDERING ALL OF THE ABOVE...WEDNESDAY SHOULD START OFF DRY
ACROSS OUR FORECAST AREA...BUT AS THE FRONT NEARS DURING THE
MIDDAY...CONVECTION WILL BEGIN TO BREAK OUT. THIS MAY BE HASTENED
ACROSS PARTS OF THE SRN TIER AND FINGER LAKES REGION WHERE A LAKE
BREEZE BOUNDARY COULD FOCUS AN INITIAL ROUND OF STORMS...THEN AS
THE FRONT SLOWLY CROSSES THE LOWER GREAT LAKES IN THE AFTERNOON
AND EVENING...THE GENERAL CONDITIONS WILL FURTHER DETERIORATE.
WILL MAINTAIN LIKELY POPS REGIONWIDE FOR THE LATE AFTERNOON...
BUT THE VAST MAJORITY OF THE DAY SHOULD BE RAIN FREE. OTHERWISE
WEDNESDAY WILL BE WARM AND HUMID WITH MAX TEMPS RANGING FROM THE
LOWER 80S OVER THE FAR WEST TO THE MID AND POSSIBLY UPPER 80S
ACROSS PARTS OF THE FINGER LAKES.
DURING THE COURSE OF WEDNESDAY NIGHT...THE FRONTAL BOUNDARY WILL
LAZILY CROSS OUR FORECAST AREA AS UPSTREAM SFC WAVES WILL RETARD
ITS FORWARD PROGRESS. THIS IS THE TIME PERIOD WHERE THE AXIS OF
THE DEEPEST MOISTURE WILL CROSS OUR FORECAST AREA. WHILE DIURNALLY
ENHANCED INSTABILITY WILL BE WANING...THE PASSAGE OF ANY WAVES
ALONG THE FRONTAL BOUNDARY COULD SYNOPTICALLY ENHANCE ANY SHOWERS
INTO A 2 TO THREE HOUR PERIOD OF STEADIER RAIN. THIS POTENTIAL
WILL BE GREATEST OVER THE SRN TIER AND FINGER LAKES REGION.
AGAIN...WE WILL BE FORTUNATE IN THAT WE HAVE VERY DRY ANTECEDENT
CONDITIONS.
ON THURSDAY...WEAK HIGH PRESSURE OVER LOWER MICHIGAN WILL
GRADUALLY BUILD ACROSS OUR FORECAST AREA WHILE THE FLEXUOUS
FRONTAL BOUNDARY WILL MAKE ITS WAY TO THE EAST COAST. SHOWERS...
THAT WILL BE MOST LIKELY EAST OF LINE FROM ROCHESTER TO
JAMESTOWN...WILL TAPER OFF FROM WEST TO EAST IN THE PROCESS.
SUNSHINE SHOULD RETURN IN FORCE TO THE NIAGARA FRONTIER AND PARTS
OF THE SRN TIER BY THE AFTERNOON...BUT THE IMPROVEMENT WILL TAKE
LONGER FURTHER EAST. IT WILL START TO FEEL MUCH MORE COMFORTABLE
AS WELL...AS THE FRESH AIRMASS WILL START TO SETTLE OVER THE
REGION WITH DEW POINTS OVER THE WESTERN COUNTIES STEADIER FALLING
THROUGH THE 50S. AFTER NEARLY TWO WEEKS OF AFTERNOON TEMPERATURES
IN THE 80S...MAX TEMPS ON THURSDAY SHOULD FINALLY RETURN TO THE
70S.
THE GRADUAL CLEARING PROCESS WILL CONTINUE THURSDAY NIGHT AS THE
LEADING EDGE OF HIGH PRESSURE WILL WORK ACROSS OUR FORECAST AREA.
ANY LEFTOVER SHOWERS OVER EASTERN SECTIONS SHOULD END DURING THE
EVENING WITH MUCH MORE COMFORTABLE SLEEPING CONDITIONS GAINING A
FOOTHOLD OVER THE ENTIRE FORECAST AREA. OVERNIGHT LOWS WILL
GENERALLY BE IN THE 50S...WITH THE RADIATIONAL COOLING PROBABLY
LEADING TO SOME VALLEY FOG ACROSS PARTS OF THE SRN TIER AND FINGER
LAKES REGIONS.
WHILE PLEASANT WEATHER IS EXPECTED ACROSS OUR REGION ON FRIDAY...
A MID LEVEL DISTURBANCE DIGGING INTO THE GREAT LAKES LONGWAVE
TROUGH WILL ENCOURAGE SOME `BAGGINESS` IN THE SFC PRESSURE FIELD
ACROSS THE UPPER OHIO VALLEY. THIS WILL BE THE BEGINNINGS OF WHAT
COULD POTENTIALLY BE A CLOSED LOW FOR OUR REGION DURING THE
UPCOMING WEEKEND. MORE ON THIS LOW CONFIDENCE EVENT IN THE LONG
TERM SECTION BELOW. GENERALLY PARTLY SUNNY SKIES CAN BE EXPECTED
ON FRIDAY WITH AFTERNOON TEMPERATURES IN THE 70S BEING ACCOMPANIED
BY COMFORTABLY LOW HUMIDITY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
ONCE AGAIN...THE MEDIUM RANGE GUIDANCE PACKAGES ARE VASTLY
DIFFERENT IN THEIR SOLUTIONS OVER THE LOWER GREAT LAKES IN THE
DAYS 5-7 PERIOD. BOTH THE GFS AND ECMWF OPERATIONAL MODELS ARE
STUBBORNLY HOLDING ONTO THE SAME SCENARIOS THAT THEY HAVE BEEN
PREACHING FOR THE PAST COUPLE DAYS... WITH THE LATTER DEPICTING
THE DEVELOPMENT OF A STACKED STORM SYSTEM OVER SOUTHERN ONTARIO
AND THE LOWER GREAT LAKES. NEEDLESS TO SAY...THIS WOULD BE A VERY
UNSETTLED SOLUTION FOR OUR FORECAST AREA WITH FAIRLY WIDESPREAD
FREQUENT SHOWERS.
BECAUSE OF THE DISPARITY WITHIN THE GUIDANCE PACKAGES...HAVE NO
CHOICE BUT TO KEEP THE LOW/SLGT CHC BROADBRUSH POPS THAT ARE IN
CONTINUITY IN PLACE THROUGH AT LEAST THE WEEKEND.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
OUTSIDE OF SOME ISOLATED/SCATTERED SHOWERS AND THUNDERSTORMS OVER
THE HIGHER TERRAIN INLAND FROM THE LAKES... MAINLY VFR CONDITIONS
WILL PREVAIL ACROSS THE AREA LATE THIS AFTERNOON THROUGH TONIGHT.
A COLD FRONT WILL APPROACH THE AREA ON WEDNESDAY BRINGING SCATTERED
SHOWERS AND THUNDERSTORMS ACROSS THE NIAGARA FRONTIER AND SAINT
LAWRENCE RIVER VALLEY. CONVECTION WILL BECOME MORE NUMEROUS INLAND
FROM THE LAKES AND TOWARD CENTRAL NEW YORK AS THE FRONT PROGRESSES
EASTWARD TOWARD WEDNESDAY MIDDAY/AFTERNOON. OUTSIDE OF TEMPORARY
VIS/CIG REDUCTIONS IN STORMS... MAINLY VFR CONDITIONS WILL PREVAIL.
OUTLOOK...
THURSDAY...SCATTERED TO NUMEROUS SHOWERS TAPERING OFF WITH CONDITIONS
IMPROVING TO VFR.
FRIDAY...MAINLY VFR...EXCEPT IN POSSIBLE MORNING SOUTHERN TIER
VALLEY FOG.
SATURDAY AND SUNDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC COASTLINE WILL SLOWLY
DRIFT OFFSHORE THROUGH MIDWEEK. A STALLED OUT COLD FRONT DRAPED FROM
THE SAINT LAWRENCE VALLEY SOUTHWESTWARD ACROSS LAKE ONTARIO WILL LIFT
BACK NORTH OF THE REGION AS A WARM FRONT THIS AFTERNOON AND EVENING
IN RESPONSE TO DEVELOPING LOW PRESSURE ACROSS THE UPPER GREAT LAKES...
THEN THIS LATTER FEATURE WILL SLOWLY EASE ITS TRAILING COLD FRONT
ACROSS THE AREA WEDNESDAY AFTERNOON AND NIGHT.
THE INITIAL FRONTAL BOUNDARY WILL CONTINUE TO TRIGGER SCATTERED
SHOWERS AND THUNDERSTORMS AS IT LINGERS NEAR THE LOWER GREAT LAKES
THIS MORNING...WITH THESE THEN GRADUALLY DIMINISHING FROM SOUTHWEST
TO NORTHEAST THIS AFTERNOON AND EVENING AS THE BOUNDARY LIFTS AWAY
FROM OUR REGION. FOLLOWING ITS DEPARTURE...GENERALLY DRY CONDITIONS
ARE EXPECTED FOR THE BALANCE OF TONIGHT...BEFORE THE TRAILING COLD
FRONT BRINGS MORE NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES
THROUGH THE REGION WEDNESDAY AFTERNOON AND NIGHT.
WHILE ANY OF THE SHOWERS/STORMS COULD PRODUCE LOCALLY HIGHER WINDS AND
WAVES OVER THE NEXT COUPLE OF DAYS...IN GENERAL LIGHT TO MODEST WINDS
WILL PREVAIL ACROSS THE LOWER LAKES REGION THROUGH WEDNESDAY NIGHT...
ALONG WITH WAVES OF UNDER 3 FEET.
FOLLOWING THE PASSAGE OF THE FRONT...HIGH PRESSURE IS EXPECTED TO
BUILD ACROSS THE REGION THURSDAY AND FRIDAY WHILE BRINGING A RETURN
TO MORE SETTLED CONDITIONS...ALONG WITH CONTINUED LIGHT TO MODEST
WINDS AND MINIMAL WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...CHURCH/JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...CHURCH
MARINE...JJR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1000 AM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC COAST WILL CONTINUE TO BRING
MIDSUMMERLIKE CONDITIONS TO THE REGION THROUGH THE FIRST HALF OF
WEDNESDAY...BEFORE A COLD FRONT CROSSES OUR REGION BETWEEN LATER
WEDNESDAY AND WEDNESDAY NIGHT. THIS FRONT WILL BE ACCOMPANIED BY
NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES THROUGH...AND WILL
BE FOLLOWED BY PROGRESSIVELY COOLER WEATHER DURING THE REMAINDER
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
DURING THE COURSE OF TODAY...THE WEAK COLD FRONT WILL BRIEFLY STALL
OUT ALONG OR SLIGHTLY NORTH OF OUR NORTHERN PERIPHERY THIS
MORNING... BEFORE LIFTING BACK NORTH THIS AFTERNOON AS A WARM FRONT
IN RESPONSE TO THE DEVELOPMENT OF BROAD LOW PRESSURE OVER THE UPPER
GREAT LAKES. ALONG AND NEAR THIS BOUNDARY...THERE WILL BE A
CONTINUED RISK OF SHOWERS AND THUNDERSTORMS THROUGH THE DAY...WITH
THIS RISK LYING ROUGHLY FROM THE NYS THRUWAY CORRIDOR NORTHWARD
THROUGH LATE THIS MORNING...THEN DIMINISHING FROM SOUTHWEST TO
NORTHEAST LATE THIS MORNING AND THIS AFTERNOON AS THE FRONT BEGINS
LIFTING BACK NORTH.
IN ADDITION TO ANY FRONTAL CONVECTION...THE COMBINATION OF DIURNAL
HEATING OF OUR VERY WARM AND HUMID AIRMASS AND REDEVELOPING LAKE
BREEZE BOUNDARIES MAY ALSO LEAD TO THE DEVELOPMENT OF A SECOND
REGION OF ISOLATED TO SCATTERED CONVECTION ACROSS AREAS SOUTH OF
LAKE ONTARIO THIS AFTERNOON...WITH THIS PRIMARILY FOCUSED FROM
INTERIOR PORTIONS OF THE SOUTHERN TIER AND GENESEE VALLEY EASTWARD
ACROSS THE FINGER LAKES.
WITH ALL OF THE ABOVE IN MIND...HAVE CONTINUED TO DEPICT A GENERAL
SOUTHWEST-NORTHEAST GRADIENT IN PRECIPITATION PROBABILITIES FOR
TODAY...WITH THESE RANGING FROM HIGH CHANCE TO LOW LIKELY FROM
LAKE ONTARIO EASTWARD ACROSS THE SAINT LAWRENCE VALLEY AND NORTH
COUNTRY...TO BELOW SLIGHT CHANCE IN AN EXPECTED REGION OF LAKE
SHADOWING IMMEDIATELY EAST OF LAKE ERIE.
OUTSIDE OF THE AFOREMENTIONED CONVECTION...DRY WEATHER AND
MIDSUMMERLIKE WARMTH AND HUMIDITY SHOULD AGAIN PREVAIL ACROSS OUR
REGION TODAY. SURFACE DEWPOINTS WILL RANGE FROM THE LOWER 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO NEAR 70 ALONG
THE STALLED/RETREATING FRONTAL BOUNDARY...WHILE 850 MB TEMPS OF
+16C TO +19C WILL SUPPORT HIGH TEMPERATURES RANGING FROM THE LOWER
80S ACROSS THE NORTH COUNTRY TO THE MID AND UPPER 80S ACROSS MOST
OF THE REST OF THE REGION...ALONG WITH SOME 90 DEGREE READINGS
ACROSS THE NORMAL WARM SPOTS OF THE GENESEE VALLEY/FINGER LAKES.
TONIGHT...THE WARM FRONT WILL FINISH LIFTING OFF TO OUR NORTH EARLY
IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE LOSS
OF DAYTIME HEATING...ANY LINGERING CONVECTION ACROSS THE FINGER LAKES
AND NORTH COUNTRY WILL COME TO AN END THIS EVENING...LEAVING BEHIND
LARGELY DRY WEATHER FOR THE BALANCE OF THE NIGHTTIME HOURS AS OUR
REGION WILL BE FIRMLY ENTRENCHED WITHIN THE WARM SECTOR OF LOW
PRESSURE LIFTING BY WELL TO OUR NORTHWEST. THUS...WE CAN EXPECT YET
ANOTHER UNSEASONABLY WARM NIGHT ACROSS OUR REGION...WITH OVERNIGHT
LOWS AGAIN RANGING FROM THE MID 60S ACROSS INTERIOR PORTIONS OF THE
SOUTHERN TIER TO THE LOWER 70S ACROSS THE LAKE PLAINS...OR LEVELS
THAT WILL BE NOT THAT FAR OFF FROM NORMAL HIGH TEMPERATURES FOR
EARLY SEPTEMBER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TEMPERATURES WILL RETURN TO NEAR NORMAL LEVELS ACROSS THE LOWER
GREAT LAKES DURING THIS PERIOD...AS THE UPPER LEVEL FLOW ACROSS
NORTH AMERICA WILL FEATURE AN AMPLIFYING TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS WILL BE SIGNIFICANT CHANGE FROM THE
FIRST WEEK OF SEPTEMBER WHEN A PERSISTENT SUB-TROPICAL RIDGE
DOMINATED THE EASTERN HALF OF THE COUNTRY. WHILE THE RIDGE WAS NOT
OVERLY IMPRESSIVE `ON PAPER`...ITS STAYING POWER FOR THIS TIME OF
YEAR ALLOWED FOR ANOMALOUSLY WARM AIR AND PLENTY OF GULF HUMIDITY
TO CREATE THE WARMEST STRETCH OF WEATHER OUR REGION EXPERIENCED
ALL SUMMER. WITH THE PASSING OF THE LAST SUMMER HOLIDAY...MOTHER
NATURE WILL ALSO TURN THE PAGE...ALBEIT IT SLOWLY.
AS IS SO OFTEN IS THE CASE...A STRONG LATITUDINAL H25 JET
CROSSING THE NORTHERN PACIFIC WILL PLOW ACROSS THE CANADIAN
ROCKIES AND ESTABLISH A BROAD DOWNSTREAM TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS TROUGH WILL FLATTEN THE PERTINACIOUS
SUB TROPICAL RIDGE...AND IN TIME WILL DIRECT PROGRESSIVELY COOLER
CANADIAN AIR SOUTHWARDS ACROSS THE LOWER 48. THIS COOLING WILL
INITIALLY ONLY TAKE OUR TEMPERATURES BACK TOWARDS NORMAL...BUT AS
WE HEAD IN TO THE WEEKEND...WE COULD EXPERIENCE A DAY OR TWO OF
FALL LIKE CONDITIONS.
AN INVERTED SFC TROUGH EXTENDING FROM THE UPPER GREAT LAKES TO
THE CENTRAL PLAINS LATE TUESDAY NIGHT WILL GRADUALLY EVOLVE INTO A
LEGITIMATE...ALBEIT WAVY...COLD FRONT ON WEDNESDAY AS IT WILL PUSH
SOUTHEAST ACROSS THE LOWER GREAT LAKES. THE OVERALL SYNOPTIC
FORCING WITH THE SLOW MOVING FRONTAL BOUNDARY IS NOT BEING
ADVERTISED AS BEING ALL THAT IMPRESSIVE...BUT IT WILL BE ENOUGH IN
COMBINATION WITH THE MID SUMMER LIKE THERMODYNAMIC ENVIRONMENT TO
PRODUCE INCREASINGLY NUMEROUS SHOWERS AND POTENTIALLY STRONG
THUNDERSTORMS.
ADDRESSING THE FORMER FIRST...AS EARLIER MENTIONED THE FRONTAL
BOUNDARY WILL STILL BE TAKING SHAPE DURING THE DAY WEDNESDAY AS IT
WILL BE PUSHING INTO OUR FORECAST AREA. TRUE FRONTOGENETIC FORCING
FROM THE FRONT WILL THUS BE GENERALLY WEAK...ALTHOUGH HGT FALLS
AND A 120KT H25 JET OVER NORTHERN QUEBEC WILL ADD SOME LARGE SCALE
SYNOPTIC LIFT BY PLACING OUR FORECAST AREA UNDER RR QUAD OF THE
JET ENTRANCE REGION. THERMODYNAMICALLY...OUR WARM HUMID AIRMASS
WILL ALREADY BE UNSTABLE. SBCAPES WILL ALREADY BE IN THE HUNDREDS
AS WE OPEN THE DAY...AND DIMINISHING MORNING SUNSHINE WILL ONLY
ADD TO THIS INSTABILITY...PARTICULARLY OVER PARTS OF THE SRN TIER
AND FINGER LAKES REGIONS WHERE MUCAPES COULD APPROACH 2000 J/KG.
MEANWHILE A SWATH OF TROPICAL MOISTURE TO THE TUNE OF 2 INCH PWAT
VALUES WILL STREAM ACROSS OUR REGION ALONG AND AHEAD OF THE SFC
BOUNDARY...SO THIS IN COMBINATION WITH THE SYNOPTIC FORCING AND
INSTABILITY COULD RESULT IN TORRENTIAL DOWNPOURS WITH SOME OF THE
CONVECTION. FORTUNATELY...THE REGION IS PARCHED FROM A GENERAL
LACK OF RAINFALL FROM THE PAST MONTH OR SO...AND GUIDANCE IS
SUGGESTING THAT CORFIDI VECTORS WILL LENGTHEN AS THE FRONT
APPROACHES. THIS WILL LESSEN THE RISK FOR WIDESPREAD HYDRO RELATED
PROBLEMS...BUT LOCAL ISSUES WILL STILL HAVE TO BE ADDRESSED GIVEN
THE SUB TROPICAL ENVIRONMENT. THE MENTION OF TORRENTIAL DOWNPOURS
HAS ALREADY BEEN ADDED TO THE HWO PRODUCT AND TO THE GRIDDED DATA
BASE...SO WILL CONTINUE.
ALONG WITH THE THREAT FOR LOCALLY HEAVY CONVECTIVE RAINS...THERE
WILL BE AN ISOLATED RISK FOR STRONG THUNDERSTORMS. THIS POTENTIAL
WILL BE ATTENUATED BY UNIMPRESSIVE MID LEVEL LAPSE RATES UNDER 6
DEG C/KM...BUT GIVEN BULK SHEAR VALUES OF 35 TO 40 KNOTS AND THE
UNCERTAINTY AS TO HOW MUCH SUNSHINE PARTS OF THE REGION RECEIVE...
WE WILL CONTINUE TO HIGHLIGHT THE CHANCE FOR GUSTY CONVECTIVE
WINDS.
CONSIDERING ALL OF THE ABOVE...WEDNESDAY SHOULD START OFF DRY
ACROSS OUR FORECAST AREA...BUT AS THE FRONT NEARS DURING THE
MIDDAY...CONVECTION WILL BEGIN TO BREAK OUT. THIS MAY BE HASTENED
ACROSS PARTS OF THE SRN TIER AND FINGER LAKES REGION WHERE A LAKE
BREEZE BOUNDARY COULD FOCUS AN INITIAL ROUND OF STORMS...THEN AS
THE FRONT SLOWLY CROSSES THE LOWER GREAT LAKES IN THE AFTERNOON
AND EVENING...THE GENERAL CONDITIONS WILL FURTHER DETERIORATE.
WILL MAINTAIN LIKELY POPS REGIONWIDE FOR THE LATE AFTERNOON...
BUT THE VAST MAJORITY OF THE DAY SHOULD BE RAIN FREE. OTHERWISE
WEDNESDAY WILL BE WARM AND HUMID WITH MAX TEMPS RANGING FROM THE
LOWER 80S OVER THE FAR WEST TO THE MID AND POSSIBLY UPPER 80S
ACROSS PARTS OF THE FINGER LAKES.
DURING THE COURSE OF WEDNESDAY NIGHT...THE FRONTAL BOUNDARY WILL
LAZILY CROSS OUR FORECAST AREA AS UPSTREAM SFC WAVES WILL RETARD
ITS FORWARD PROGRESS. THIS IS THE TIME PERIOD WHERE THE AXIS OF
THE DEEPEST MOISTURE WILL CROSS OUR FORECAST AREA. WHILE DIURNALLY
ENHANCED INSTABILITY WILL BE WANING...THE PASSAGE OF ANY WAVES
ALONG THE FRONTAL BOUNDARY COULD SYNOPTICALLY ENHANCE ANY SHOWERS
INTO A 2 TO THREE HOUR PERIOD OF STEADIER RAIN. THIS POTENTIAL
WILL BE GREATEST OVER THE SRN TIER AND FINGER LAKES REGION.
AGAIN...WE WILL BE FORTUNATE IN THAT WE HAVE VERY DRY ANTECEDENT
CONDITIONS.
ON THURSDAY...WEAK HIGH PRESSURE OVER LOWER MICHIGAN WILL
GRADUALLY BUILD ACROSS OUR FORECAST AREA WHILE THE FLEXUOUS
FRONTAL BOUNDARY WILL MAKE ITS WAY TO THE EAST COAST. SHOWERS...
THAT WILL BE MOST LIKELY EAST OF LINE FROM ROCHESTER TO
JAMESTOWN...WILL TAPER OFF FROM WEST TO EAST IN THE PROCESS.
SUNSHINE SHOULD RETURN IN FORCE TO THE NIAGARA FRONTIER AND PARTS
OF THE SRN TIER BY THE AFTERNOON...BUT THE IMPROVEMENT WILL TAKE
LONGER FURTHER EAST. IT WILL START TO FEEL MUCH MORE COMFORTABLE
AS WELL...AS THE FRESH AIRMASS WILL START TO SETTLE OVER THE
REGION WITH DEW POINTS OVER THE WESTERN COUNTIES STEADIER FALLING
THROUGH THE 50S. AFTER NEARLY TWO WEEKS OF AFTERNOON TEMPERATURES
IN THE 80S...MAX TEMPS ON THURSDAY SHOULD FINALLY RETURN TO THE
70S.
THE GRADUAL CLEARING PROCESS WILL CONTINUE THURSDAY NIGHT AS THE
LEADING EDGE OF HIGH PRESSURE WILL WORK ACROSS OUR FORECAST AREA.
ANY LEFTOVER SHOWERS OVER EASTERN SECTIONS SHOULD END DURING THE
EVENING WITH MUCH MORE COMFORTABLE SLEEPING CONDITIONS GAINING A
FOOTHOLD OVER THE ENTIRE FORECAST AREA. OVERNIGHT LOWS WILL
GENERALLY BE IN THE 50S...WITH THE RADIATIONAL COOLING PROBABLY
LEADING TO SOME VALLEY FOG ACROSS PARTS OF THE SRN TIER AND FINGER
LAKES REGIONS.
WHILE PLEASANT WEATHER IS EXPECTED ACROSS OUR REGION ON FRIDAY...
A MID LEVEL DISTURBANCE DIGGING INTO THE GREAT LAKES LONGWAVE
TROUGH WILL ENCOURAGE SOME `BAGGINESS` IN THE SFC PRESSURE FIELD
ACROSS THE UPPER OHIO VALLEY. THIS WILL BE THE BEGINNINGS OF WHAT
COULD POTENTIALLY BE A CLOSED LOW FOR OUR REGION DURING THE
UPCOMING WEEKEND. MORE ON THIS LOW CONFIDENCE EVENT IN THE LONG
TERM SECTION BELOW. GENERALLY PARTLY SUNNY SKIES CAN BE EXPECTED
ON FRIDAY WITH AFTERNOON TEMPERATURES IN THE 70S BEING ACCOMPANIED
BY COMFORTABLY LOW HUMIDITY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
ONCE AGAIN...THE MEDIUM RANGE GUIDANCE PACKAGES ARE VASTLY
DIFFERENT IN THEIR SOLUTIONS OVER THE LOWER GREAT LAKES IN THE
DAYS 5-7 PERIOD. BOTH THE GFS AND ECMWF OPERATIONAL MODELS ARE
STUBBORNLY HOLDING ONTO THE SAME SCENARIOS THAT THEY HAVE BEEN
PREACHING FOR THE PAST COUPLE DAYS... WITH THE LATTER DEPICTING
THE DEVELOPMENT OF A STACKED STORM SYSTEM OVER SOUTHERN ONTARIO
AND THE LOWER GREAT LAKES. NEEDLESS TO SAY...THIS WOULD BE A VERY
UNSETTLED SOLUTION FOR OUR FORECAST AREA WITH FAIRLY WIDESPREAD
FREQUENT SHOWERS.
BECAUSE OF THE DISPARITY WITHIN THE GUIDANCE PACKAGES...HAVE NO
CHOICE BUT TO KEEP THE LOW/SLGT CHC BROADBRUSH POPS THAT ARE IN
CONTINUITY IN PLACE THROUGH AT LEAST THE WEEKEND.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
A WEAK COLD FRONT WILL BRIEFLY STALL OUT ALONG OR SLIGHTLY NORTH
OF OUR NORTHERN PERIPHERY THIS MORNING...BEFORE LIFTING BACK
NORTH THIS AFTERNOON AS A WARM FRONT IN RESPONSE TO THE DEVELOPMENT
OF BROAD LOW PRESSURE OVER THE UPPER GREAT LAKES. THERE WILL BE
A CONTINUED RISK OF SHOWERS/THUNDERSTORMS AND ATTENDANT RESTRICTIONS
ALONG AND NEAR THIS BOUNDARY THROUGH THE DAY...AND ALSO ALONG AND
INLAND FROM A DEVELOPING LAKE ERIE LAKE BREEZE BOUNDARY DURING THE
AFTERNOON. OUTSIDE OF ANY SUCH CONVECTION AND ANY EARLY MORNING
MVFR SOUTHERN TIER VALLEY FOG... VFR CONDITIONS SHOULD OTHERWISE
PREVAIL.
TONIGHT...THE FRONTAL BOUNDARY WILL FINISH LIFTING OFF TO OUR NORTH
EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE LOSS
OF DAYTIME HEATING...ANY LINGERING CONVECTION/ATTENDANT RESTRICTIONS
ACROSS THE FINGER LAKES AND NORTH COUNTRY WILL COME TO AN END THIS
EVENING...LEAVING BEHIND LARGELY DRY/VFR CONDITIONS FOR THE BALANCE
OF THE NIGHTTIME HOURS.
OUTLOOK...
WEDNESDAY...MAINLY VFR INITIALLY...THEN SHOWERS AND THUNDERSTORMS
WITH ATTENDANT REDUCTIONS TO IFR/MVFR BECOMING LIKELY FOR WEDNESDAY
AFTERNOON AND EVENING.
THURSDAY...SCATTERED TO NUMEROUS SHOWERS TAPERING OFF WITH CONDITIONS
IMPROVING TO VFR.
FRIDAY...MAINLY VFR...EXCEPT IN POSSIBLE MORNING SOUTHERN TIER
VALLEY FOG.
SATURDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC COASTLINE WILL SLOWLY
DRIFT OFFSHORE THROUGH MIDWEEK. A STALLED OUT COLD FRONT DRAPED FROM
THE SAINT LAWRENCE VALLEY SOUTHWESTWARD ACROSS LAKE ONTARIO WILL LIFT
BACK NORTH OF THE REGION AS A WARM FRONT THIS AFTERNOON AND EVENING
IN RESPONSE TO DEVELOPING LOW PRESSURE ACROSS THE UPPER GREAT LAKES...
THEN THIS LATTER FEATURE WILL SLOWLY EASE ITS TRAILING COLD FRONT
ACROSS THE AREA WEDNESDAY AFTERNOON AND NIGHT.
THE INITIAL FRONTAL BOUNDARY WILL CONTINUE TO TRIGGER SCATTERED
SHOWERS AND THUNDERSTORMS AS IT LINGERS NEAR THE LOWER GREAT LAKES
THIS MORNING...WITH THESE THEN GRADUALLY DIMINISHING FROM SOUTHWEST
TO NORTHEAST THIS AFTERNOON AND EVENING AS THE BOUNDARY LIFTS AWAY
FROM OUR REGION. FOLLOWING ITS DEPARTURE...GENERALLY DRY CONDITIONS
ARE EXPECTED FOR THE BALANCE OF TONIGHT...BEFORE THE TRAILING COLD
FRONT BRINGS MORE NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES
THROUGH THE REGION WEDNESDAY AFTERNOON AND NIGHT.
WHILE ANY OF THE SHOWERS/STORMS COULD PRODUCE LOCALLY HIGHER WINDS AND
WAVES OVER THE NEXT COUPLE OF DAYS...IN GENERAL LIGHT TO MODEST WINDS
WILL PREVAIL ACROSS THE LOWER LAKES REGION THROUGH WEDNESDAY NIGHT...
ALONG WITH WAVES OF UNDER 3 FEET.
FOLLOWING THE PASSAGE OF THE FRONT...HIGH PRESSURE IS EXPECTED TO
BUILD ACROSS THE REGION THURSDAY AND FRIDAY WHILE BRINGING A RETURN
TO MORE SETTLED CONDITIONS...ALONG WITH CONTINUED LIGHT TO MODEST
WINDS AND MINIMAL WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...CHURCH/JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...JJR
MARINE...JJR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
732 AM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC COAST WILL CONTINUE TO BRING
MIDSUMMERLIKE CONDITIONS TO THE REGION THROUGH THE FIRST HALF OF
WEDNESDAY...BEFORE A COLD FRONT CROSSES OUR REGION BETWEEN LATER
WEDNESDAY AND WEDNESDAY NIGHT. THIS FRONT WILL BE ACCOMPANIED BY
NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES THROUGH...AND WILL
BE FOLLOWED BY PROGRESSIVELY COOLER WEATHER DURING THE REMAINDER
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1130Z...REGIONAL SURFACE OBSERVATIONS SUGGEST THAT THE WEAK
COLD FRONTAL BOUNDARY EXTENDS FROM THE SAINT LAWRENCE VALLEY
ACROSS NORTHERN LAKE ONTARIO TO THE GREATER TORONTO AREA...AND
THEN ON ACROSS SOUTHWESTERN ONTARIO. ALONG AND NEAR THIS BOUNDARY...
REGIONAL RADARS DEPICT AN ELONGATED SWATH OF SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS...WITH THE MOST NUMEROUS ACTIVITY NOW
WORKING INTO THE GOLDEN HORSESHOE REGION OF ONTARIO.
DURING THE COURSE OF TODAY...THE WEAK COLD FRONT WILL BRIEFLY STALL
OUT ALONG OR SLIGHTLY NORTH OF OUR NORTHERN PERIPHERY THIS MORNING...
BEFORE LIFTING BACK NORTH THIS AFTERNOON AS A WARM FRONT IN RESPONSE
TO THE DEVELOPMENT OF BROAD LOW PRESSURE OVER THE UPPER GREAT LAKES.
ALONG AND NEAR THIS BOUNDARY...THERE WILL BE A CONTINUED RISK OF
SHOWERS AND THUNDERSTORMS THROUGH THE DAY...WITH THIS RISK LYING
ROUGHLY FROM THE NYS THRUWAY CORRIDOR NORTHWARD THROUGH LATE THIS
MORNING...THEN DIMINISHING FROM SOUTHWEST TO NORTHEAST LATE THIS
MORNING AND THIS AFTERNOON AS THE FRONT BEGINS LIFTING BACK NORTH.
IN ADDITION TO ANY FRONTAL CONVECTION...THE COMBINATION OF DIURNAL
HEATING OF OUR VERY WARM AND HUMID AIRMASS AND REDEVELOPING LAKE
BREEZE BOUNDARIES MAY ALSO LEAD TO THE DEVELOPMENT OF A SECOND
REGION OF ISOLATED TO SCATTERED CONVECTION ACROSS AREAS SOUTH OF
LAKE ONTARIO THIS AFTERNOON...WITH THIS PRIMARILY FOCUSED FROM
INTERIOR PORTIONS OF THE SOUTHERN TIER AND GENESEE VALLEY EASTWARD
ACROSS THE FINGER LAKES.
WITH ALL OF THE ABOVE IN MIND...HAVE CONTINUED TO DEPICT A GENERAL
SOUTHWEST-NORTHEAST GRADIENT IN PRECIPITATION PROBABILITIES FOR
TODAY...WITH THESE RANGING FROM HIGH CHANCE TO LOW LIKELY FROM
LAKE ONTARIO EASTWARD ACROSS THE SAINT LAWRENCE VALLEY AND NORTH
COUNTRY...TO BELOW SLIGHT CHANCE IN AN EXPECTED REGION OF LAKE
SHADOWING IMMEDIATELY EAST OF LAKE ERIE.
OUTSIDE OF THE AFOREMENTIONED CONVECTION...DRY WEATHER AND
MIDSUMMERLIKE WARMTH AND HUMIDITY SHOULD AGAIN PREVAIL ACROSS OUR
REGION TODAY. SURFACE DEWPOINTS WILL RANGE FROM THE LOWER 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO NEAR 70 ALONG
THE STALLED/RETREATING FRONTAL BOUNDARY...WHILE 850 MB TEMPS OF
+16C TO +19C WILL SUPPORT HIGH TEMPERATURES RANGING FROM THE LOWER
80S ACROSS THE NORTH COUNTRY TO THE MID AND UPPER 80S ACROSS MOST
OF THE REST OF THE REGION...ALONG WITH SOME 90 DEGREE READINGS
ACROSS THE NORMAL WARM SPOTS OF THE GENESEE VALLEY/FINGER LAKES.
TONIGHT...THE WARM FRONT WILL FINISH LIFTING OFF TO OUR NORTH EARLY
IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE LOSS
OF DAYTIME HEATING...ANY LINGERING CONVECTION ACROSS THE FINGER LAKES
AND NORTH COUNTRY WILL COME TO AN END THIS EVENING...LEAVING BEHIND
LARGELY DRY WEATHER FOR THE BALANCE OF THE NIGHTTIME HOURS AS OUR
REGION WILL BE FIRMLY ENTRENCHED WITHIN THE WARM SECTOR OF LOW
PRESSURE LIFTING BY WELL TO OUR NORTHWEST. THUS...WE CAN EXPECT YET
ANOTHER UNSEASONABLY WARM NIGHT ACROSS OUR REGION...WITH OVERNIGHT
LOWS AGAIN RANGING FROM THE MID 60S ACROSS INTERIOR PORTIONS OF THE
SOUTHERN TIER TO THE LOWER 70S ACROSS THE LAKE PLAINS...OR LEVELS
THAT WILL BE NOT THAT FAR OFF FROM NORMAL HIGH TEMPERATURES FOR
EARLY SEPTEMBER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TEMPERATURES WILL RETURN TO NEAR NORMAL LEVELS ACROSS THE LOWER
GREAT LAKES DURING THIS PERIOD...AS THE UPPER LEVEL FLOW ACROSS
NORTH AMERICA WILL FEATURE AN AMPLIFYING TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS WILL BE SIGNIFICANT CHANGE FROM THE
FIRST WEEK OF SEPTEMBER WHEN A PERSISTENT SUB-TROPICAL RIDGE
DOMINATED THE EASTERN HALF OF THE COUNTRY. WHILE THE RIDGE WAS NOT
OVERLY IMPRESSIVE `ON PAPER`...ITS STAYING POWER FOR THIS TIME OF
YEAR ALLOWED FOR ANOMALOUSLY WARM AIR AND PLENTY OF GULF HUMIDITY
TO CREATE THE WARMEST STRETCH OF WEATHER OUR REGION EXPERIENCED
ALL SUMMER. WITH THE PASSING OF THE LAST SUMMER HOLIDAY...MOTHER
NATURE WILL ALSO TURN THE PAGE...ALBEIT IT SLOWLY.
AS IS SO OFTEN IS THE CASE...A STRONG LATITUDINAL H25 JET
CROSSING THE NORTHERN PACIFIC WILL PLOW ACROSS THE CANADIAN
ROCKIES AND ESTABLISH A BROAD DOWNSTREAM TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS TROUGH WILL FLATTEN THE PERTINACIOUS
SUB TROPICAL RIDGE...AND IN TIME WILL DIRECT PROGRESSIVELY COOLER
CANADIAN AIR SOUTHWARDS ACROSS THE LOWER 48. THIS COOLING WILL
INITIALLY ONLY TAKE OUR TEMPERATURES BACK TOWARDS NORMAL...BUT AS
WE HEAD IN TO THE WEEKEND...WE COULD EXPERIENCE A DAY OR TWO OF
FALL LIKE CONDITIONS.
AN INVERTED SFC TROUGH EXTENDING FROM THE UPPER GREAT LAKES TO
THE CENTRAL PLAINS LATE TUESDAY NIGHT WILL GRADUALLY EVOLVE INTO A
LEGITIMATE...ALBEIT WAVY...COLD FRONT ON WEDNESDAY AS IT WILL PUSH
SOUTHEAST ACROSS THE LOWER GREAT LAKES. THE OVERALL SYNOPTIC
FORCING WITH THE SLOW MOVING FRONTAL BOUNDARY IS NOT BEING
ADVERTISED AS BEING ALL THAT IMPRESSIVE...BUT IT WILL BE ENOUGH IN
COMBINATION WITH THE MID SUMMER LIKE THERMODYNAMIC ENVIRONMENT TO
PRODUCE INCREASINGLY NUMEROUS SHOWERS AND POTENTIALLY STRONG
THUNDERSTORMS.
ADDRESSING THE FORMER FIRST...AS EARLIER MENTIONED THE FRONTAL
BOUNDARY WILL STILL BE TAKING SHAPE DURING THE DAY WEDNESDAY AS IT
WILL BE PUSHING INTO OUR FORECAST AREA. TRUE FRONTOGENETIC FORCING
FROM THE FRONT WILL THUS BE GENERALLY WEAK...ALTHOUGH HGT FALLS
AND A 120KT H25 JET OVER NORTHERN QUEBEC WILL ADD SOME LARGE SCALE
SYNOPTIC LIFT BY PLACING OUR FORECAST AREA UNDER RR QUAD OF THE
JET ENTRANCE REGION. THERMODYNAMICALLY...OUR WARM HUMID AIRMASS
WILL ALREADY BE UNSTABLE. SBCAPES WILL ALREADY BE IN THE HUNDREDS
AS WE OPEN THE DAY...AND DIMINISHING MORNING SUNSHINE WILL ONLY
ADD TO THIS INSTABILITY...PARTICULARLY OVER PARTS OF THE SRN TIER
AND FINGER LAKES REGIONS WHERE MUCAPES COULD APPROACH 2000 J/KG.
MEANWHILE A SWATH OF TROPICAL MOISTURE TO THE TUNE OF 2 INCH PWAT
VALUES WILL STREAM ACROSS OUR REGION ALONG AND AHEAD OF THE SFC
BOUNDARY...SO THIS IN COMBINATION WITH THE SYNOPTIC FORCING AND
INSTABILITY COULD RESULT IN TORRENTIAL DOWNPOURS WITH SOME OF THE
CONVECTION. FORTUNATELY...THE REGION IS PARCHED FROM A GENERAL
LACK OF RAINFALL FROM THE PAST MONTH OR SO...AND GUIDANCE IS
SUGGESTING THAT CORFIDI VECTORS WILL LENGTHEN AS THE FRONT
APPROACHES. THIS WILL LESSEN THE RISK FOR WIDESPREAD HYDRO RELATED
PROBLEMS...BUT LOCAL ISSUES WILL STILL HAVE TO BE ADDRESSED GIVEN
THE SUB TROPICAL ENVIRONMENT. THE MENTION OF TORRENTIAL DOWNPOURS
HAS ALREADY BEEN ADDED TO THE HWO PRODUCT AND TO THE GRIDDED DATA
BASE...SO WILL CONTINUE.
ALONG WITH THE THREAT FOR LOCALLY HEAVY CONVECTIVE RAINS...THERE
WILL BE AN ISOLATED RISK FOR STRONG THUNDERSTORMS. THIS POTENTIAL
WILL BE ATTENUATED BY UNIMPRESSIVE MID LEVEL LAPSE RATES UNDER 6
DEG C/KM...BUT GIVEN BULK SHEAR VALUES OF 35 TO 40 KNOTS AND THE
UNCERTAINTY AS TO HOW MUCH SUNSHINE PARTS OF THE REGION RECEIVE...
WE WILL CONTINUE TO HIGHLIGHT THE CHANCE FOR GUSTY CONVECTIVE
WINDS.
CONSIDERING ALL OF THE ABOVE...WEDNESDAY SHOULD START OFF DRY
ACROSS OUR FORECAST AREA...BUT AS THE FRONT NEARS DURING THE
MIDDAY...CONVECTION WILL BEGIN TO BREAK OUT. THIS MAY BE HASTENED
ACROSS PARTS OF THE SRN TIER AND FINGER LAKES REGION WHERE A LAKE
BREEZE BOUNDARY COULD FOCUS AN INITIAL ROUND OF STORMS...THEN AS
THE FRONT SLOWLY CROSSES THE LOWER GREAT LAKES IN THE AFTERNOON
AND EVENING...THE GENERAL CONDITIONS WILL FURTHER DETERIORATE.
WILL MAINTAIN LIKELY POPS REGIONWIDE FOR THE LATE AFTERNOON...
BUT THE VAST MAJORITY OF THE DAY SHOULD BE RAIN FREE. OTHERWISE
WEDNESDAY WILL BE WARM AND HUMID WITH MAX TEMPS RANGING FROM THE
LOWER 80S OVER THE FAR WEST TO THE MID AND POSSIBLY UPPER 80S
ACROSS PARTS OF THE FINGER LAKES.
DURING THE COURSE OF WEDNESDAY NIGHT...THE FRONTAL BOUNDARY WILL
LAZILY CROSS OUR FORECAST AREA AS UPSTREAM SFC WAVES WILL RETARD
ITS FORWARD PROGRESS. THIS IS THE TIME PERIOD WHERE THE AXIS OF
THE DEEPEST MOISTURE WILL CROSS OUR FORECAST AREA. WHILE DIURNALLY
ENHANCED INSTABILITY WILL BE WANING...THE PASSAGE OF ANY WAVES
ALONG THE FRONTAL BOUNDARY COULD SYNOPTICALLY ENHANCE ANY SHOWERS
INTO A 2 TO THREE HOUR PERIOD OF STEADIER RAIN. THIS POTENTIAL
WILL BE GREATEST OVER THE SRN TIER AND FINGER LAKES REGION.
AGAIN...WE WILL BE FORTUNATE IN THAT WE HAVE VERY DRY ANTECEDENT
CONDITIONS.
ON THURSDAY...WEAK HIGH PRESSURE OVER LOWER MICHIGAN WILL
GRADUALLY BUILD ACROSS OUR FORECAST AREA WHILE THE FLEXUOUS
FRONTAL BOUNDARY WILL MAKE ITS WAY TO THE EAST COAST. SHOWERS...
THAT WILL BE MOST LIKELY EAST OF LINE FROM ROCHESTER TO
JAMESTOWN...WILL TAPER OFF FROM WEST TO EAST IN THE PROCESS.
SUNSHINE SHOULD RETURN IN FORCE TO THE NIAGARA FRONTIER AND PARTS
OF THE SRN TIER BY THE AFTERNOON...BUT THE IMPROVEMENT WILL TAKE
LONGER FURTHER EAST. IT WILL START TO FEEL MUCH MORE COMFORTABLE
AS WELL...AS THE FRESH AIRMASS WILL START TO SETTLE OVER THE
REGION WITH DEW POINTS OVER THE WESTERN COUNTIES STEADIER FALLING
THROUGH THE 50S. AFTER NEARLY TWO WEEKS OF AFTERNOON TEMPERATURES
IN THE 80S...MAX TEMPS ON THURSDAY SHOULD FINALLY RETURN TO THE
70S.
THE GRADUAL CLEARING PROCESS WILL CONTINUE THURSDAY NIGHT AS THE
LEADING EDGE OF HIGH PRESSURE WILL WORK ACROSS OUR FORECAST AREA.
ANY LEFTOVER SHOWERS OVER EASTERN SECTIONS SHOULD END DURING THE
EVENING WITH MUCH MORE COMFORTABLE SLEEPING CONDITIONS GAINING A
FOOTHOLD OVER THE ENTIRE FORECAST AREA. OVERNIGHT LOWS WILL
GENERALLY BE IN THE 50S...WITH THE RADIATIONAL COOLING PROBABLY
LEADING TO SOME VALLEY FOG ACROSS PARTS OF THE SRN TIER AND FINGER
LAKES REGIONS.
WHILE PLEASANT WEATHER IS EXPECTED ACROSS OUR REGION ON FRIDAY...
A MID LEVEL DISTURBANCE DIGGING INTO THE GREAT LAKES LONGWAVE
TROUGH WILL ENCOURAGE SOME `BAGGINESS` IN THE SFC PRESSURE FIELD
ACROSS THE UPPER OHIO VALLEY. THIS WILL BE THE BEGINNINGS OF WHAT
COULD POTENTIALLY BE A CLOSED LOW FOR OUR REGION DURING THE
UPCOMING WEEKEND. MORE ON THIS LOW CONFIDENCE EVENT IN THE LONG
TERM SECTION BELOW. GENERALLY PARTLY SUNNY SKIES CAN BE EXPECTED
ON FRIDAY WITH AFTERNOON TEMPERATURES IN THE 70S BEING ACCOMPANIED
BY COMFORTABLY LOW HUMIDITY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
ONCE AGAIN...THE MEDIUM RANGE GUIDANCE PACKAGES ARE VASTLY
DIFFERENT IN THEIR SOLUTIONS OVER THE LOWER GREAT LAKES IN THE
DAYS 5-7 PERIOD. BOTH THE GFS AND ECMWF OPERATIONAL MODELS ARE
STUBBORNLY HOLDING ONTO THE SAME SCENARIOS THAT THEY HAVE BEEN
PREACHING FOR THE PAST COUPLE DAYS... WITH THE LATTER DEPICTING
THE DEVELOPMENT OF A STACKED STORM SYSTEM OVER SOUTHERN ONTARIO
AND THE LOWER GREAT LAKES. NEEDLESS TO SAY...THIS WOULD BE A VERY
UNSETTLED SOLUTION FOR OUR FORECAST AREA WITH FAIRLY WIDESPREAD
FREQUENT SHOWERS.
BECAUSE OF THE DISPARITY WITHIN THE GUIDANCE PACKAGES...HAVE NO
CHOICE BUT TO KEEP THE LOW/SLGT CHC BROADBRUSH POPS THAT ARE IN
CONTINUITY IN PLACE THROUGH AT LEAST THE WEEKEND.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
A WEAK COLD FRONT WILL BRIEFLY STALL OUT ALONG OR SLIGHTLY NORTH
OF OUR NORTHERN PERIPHERY THIS MORNING...BEFORE LIFTING BACK
NORTH THIS AFTERNOON AS A WARM FRONT IN RESPONSE TO THE DEVELOPMENT
OF BROAD LOW PRESSURE OVER THE UPPER GREAT LAKES. THERE WILL BE
A CONTINUED RISK OF SHOWERS/THUNDERSTORMS AND ATTENDANT RESTRICTIONS
ALONG AND NEAR THIS BOUNDARY THROUGH THE DAY...AND ALSO ALONG AND
INLAND FROM A DEVELOPING LAKE ERIE LAKE BREEZE BOUNDARY DURING THE
AFTERNOON. OUTSIDE OF ANY SUCH CONVECTION AND ANY EARLY MORNING
MVFR SOUTHERN TIER VALLEY FOG... VFR CONDITIONS SHOULD OTHERWISE
PREVAIL.
TONIGHT...THE FRONTAL BOUNDARY WILL FINISH LIFTING OFF TO OUR NORTH
EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE LOSS
OF DAYTIME HEATING...ANY LINGERING CONVECTION/ATTENDANT RESTRICTIONS
ACROSS THE FINGER LAKES AND NORTH COUNTRY WILL COME TO AN END THIS
EVENING...LEAVING BEHIND LARGELY DRY/VFR CONDITIONS FOR THE BALANCE
OF THE NIGHTTIME HOURS.
OUTLOOK...
WEDNESDAY...MAINLY VFR INITIALLY...THEN SHOWERS AND THUNDERSTORMS
WITH ATTENDANT REDUCTIONS TO IFR/MVFR BECOMING LIKELY FOR WEDNESDAY
AFTERNOON AND EVENING.
THURSDAY...SCATTERED TO NUMEROUS SHOWERS TAPERING OFF WITH CONDITIONS
IMPROVING TO VFR.
FRIDAY...MAINLY VFR...EXCEPT IN POSSIBLE MORNING SOUTHERN TIER
VALLEY FOG.
SATURDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC COASTLINE WILL SLOWLY
DRIFT OFFSHORE THROUGH MIDWEEK. A STALLED OUT COLD FRONT DRAPED FROM
THE SAINT LAWRENCE VALLEY SOUTHWESTWARD ACROSS LAKE ONTARIO WILL LIFT
BACK NORTH OF THE REGION AS A WARM FRONT THIS AFTERNOON AND EVENING
IN RESPONSE TO DEVELOPING LOW PRESSURE ACROSS THE UPPER GREAT LAKES...
THEN THIS LATTER FEATURE WILL SLOWLY EASE ITS TRAILING COLD FRONT
ACROSS THE AREA WEDNESDAY AFTERNOON AND NIGHT.
THE INITIAL FRONTAL BOUNDARY WILL CONTINUE TO TRIGGER SCATTERED
SHOWERS AND THUNDERSTORMS AS IT LINGERS NEAR THE LOWER GREAT LAKES
THIS MORNING...WITH THESE THEN GRADUALLY DIMINISHING FROM SOUTHWEST
TO NORTHEAST THIS AFTERNOON AND EVENING AS THE BOUNDARY LIFTS AWAY
FROM OUR REGION. FOLLOWING ITS DEPARTURE...GENERALLY DRY CONDITIONS
ARE EXPECTED FOR THE BALANCE OF TONIGHT...BEFORE THE TRAILING COLD
FRONT BRINGS MORE NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES
THROUGH THE REGION WEDNESDAY AFTERNOON AND NIGHT.
WHILE ANY OF THE SHOWERS/STORMS COULD PRODUCE LOCALLY HIGHER WINDS AND
WAVES OVER THE NEXT COUPLE OF DAYS...IN GENERAL LIGHT TO MODEST WINDS
WILL PREVAIL ACROSS THE LOWER LAKES REGION THROUGH WEDNESDAY NIGHT...
ALONG WITH WAVES OF UNDER 3 FEET.
FOLLOWING THE PASSAGE OF THE FRONT...HIGH PRESSURE IS EXPECTED TO
BUILD ACROSS THE REGION THURSDAY AND FRIDAY WHILE BRINGING A RETURN
TO MORE SETTLED CONDITIONS...ALONG WITH CONTINUED LIGHT TO MODEST
WINDS AND MINIMAL WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...JJR
MARINE...JJR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
542 AM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC COAST WILL CONTINUE TO BRING
MIDSUMMERLIKE CONDITIONS TO THE REGION THROUGH THE FIRST HALF OF
WEDNESDAY...BEFORE A COLD FRONT CROSSES OUR REGION BETWEEN LATER
WEDNESDAY AND WEDNESDAY NIGHT. THIS FRONT WILL BE ACCOMPANIED BY
NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES THROUGH...AND WILL
BE FOLLOWED BY PROGRESSIVELY COOLER WEATHER DURING THE REMAINDER
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 08Z...REGIONAL SURFACE OBSERVATIONS SUGGEST THAT THE WEAK
COLD FRONTAL BOUNDARY EXTENDS FROM THE SAINT LAWRENCE VALLEY
ACROSS NORTHERN LAKE ONTARIO TO THE GREATER TORONTO AREA...AND
THEN ON ACROSS SOUTHWESTERN ONTARIO. ALONG AND NEAR THIS
BOUNDARY...REGIONAL RADARS CONTINUE TO DEPICT AN ELONGATED SWATH
OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS.
DURING THE COURSE OF TODAY...THE WEAK COLD FRONT WILL BRIEFLY
STALL OUT ALONG OR SLIGHTLY NORTH OF OUR NORTHERN PERIPHERY THIS
MORNING... BEFORE LIFTING BACK NORTH THIS AFTERNOON AS A WARM
FRONT IN RESPONSE TO THE DEVELOPMENT OF BROAD LOW PRESSURE OVER
THE UPPER GREAT LAKES. ALONG AND NEAR THIS BOUNDARY...THERE WILL
BE A CONTINUED RISK OF SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
THE DAY...WITH THIS RISK LYING ROUGHLY FROM THE NYS THRUWAY
CORRIDOR NORTHWARD THROUGH LATE THIS MORNING...THEN DIMINISHING
FROM SOUTHWEST TO NORTHEAST LATE THIS MORNING AND THIS AFTERNOON
AS THE FRONT BEGINS LIFTING BACK NORTH.
IN ADDITION TO ANY FRONTAL CONVECTION...THE COMBINATION OF
DIURNAL HEATING OF OUR VERY WARM AND HUMID AIRMASS AND
REDEVELOPING LAKE BREEZE BOUNDARIES MAY ALSO LEAD TO THE
DEVELOPMENT OF A SECOND REGION OF ISOLATED TO SCATTERED CONVECTION
ACROSS AREAS SOUTH OF LAKE ONTARIO THIS AFTERNOON...WITH THIS
PRIMARILY FOCUSED FROM INTERIOR PORTIONS OF THE SOUTHERN TIER AND
GENESEE VALLEY EASTWARD ACROSS THE FINGER LAKES.
WITH ALL OF THE ABOVE IN MIND...HAVE CONTINUED TO DEPICT A
GENERAL SOUTHWEST-NORTHEAST GRADIENT IN PRECIPITATION
PROBABILITIES FOR TODAY...WITH THESE RANGING FROM HIGH CHANCE
ACROSS THE SAINT LAWRENCE VALLEY AND NORTH COUNTRY...TO BELOW
SLIGHT CHANCE IN AN EXPECTED REGION OF LAKE SHADOWING IMMEDIATELY
EAST OF LAKE ERIE.
OUTSIDE OF THE AFOREMENTIONED CONVECTION...DRY WEATHER AND
MIDSUMMERLIKE WARMTH AND HUMIDITY SHOULD AGAIN PREVAIL ACROSS OUR
REGION TODAY. SURFACE DEWPOINTS WILL RANGE FROM THE LOWER 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO NEAR 70 ALONG THE
STALLED/RETREATING FRONTAL BOUNDARY...WHILE 850 MB TEMPS OF +16C
TO +19C WILL SUPPORT HIGH TEMPERATURES RANGING FROM THE LOWER 80S
ACROSS THE NORTH COUNTRY TO THE MID AND UPPER 80S ACROSS MOST OF
THE REST OF THE REGION...ALONG WITH SOME 90 DEGREE READINGS ACROSS
THE NORMAL WARM SPOTS OF THE GENESEE VALLEY/FINGER LAKES.
TONIGHT...THE WARM FRONT WILL FINISH LIFTING OFF TO OUR NORTH
EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE
LOSS OF DAYTIME HEATING...ANY LINGERING CONVECTION ACROSS THE
FINGER LAKES AND NORTH COUNTRY WILL COME TO AN END THIS
EVENING...LEAVING BEHIND LARGELY DRY WEATHER FOR THE BALANCE OF
THE NIGHTTIME HOURS AS OUR REGION WILL BE FIRMLY ENTRENCHED WITHIN
THE WARM SECTOR OF LOW PRESSURE LIFTING BY WELL TO OUR NORTHWEST.
THUS...WE CAN EXPECT YET ANOTHER UNSEASONABLY WARM NIGHT ACROSS
OUR REGION...WITH OVERNIGHT LOWS AGAIN RANGING FROM THE MID 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO THE LOWER 70S
ACROSS THE LAKE PLAINS...OR LEVELS THAT WILL BE NOT THAT FAR OFF
FROM NORMAL HIGH TEMPERATURES FOR EARLY SEPTEMBER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TEMPERATURES WILL RETURN TO NEAR NORMAL LEVELS ACROSS THE LOWER
GREAT LAKES DURING THIS PERIOD...AS THE UPPER LEVEL FLOW ACROSS
NORTH AMERICA WILL FEATURE AN AMPLIFYING TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS WILL BE SIGNIFICANT CHANGE FROM THE
FIRST WEEK OF SEPTEMBER WHEN A PERSISTENT SUB-TROPICAL RIDGE
DOMINATED THE EASTERN HALF OF THE COUNTRY. WHILE THE RIDGE WAS NOT
OVERLY IMPRESSIVE `ON PAPER`...ITS STAYING POWER FOR THIS TIME OF
YEAR ALLOWED FOR ANOMALOUSLY WARM AIR AND PLENTY OF GULF HUMIDITY
TO CREATE THE WARMEST STRETCH OF WEATHER OUR REGION EXPERIENCED
ALL SUMMER. WITH THE PASSING OF THE LAST SUMMER HOLIDAY...MOTHER
NATURE WILL ALSO TURN THE PAGE...ALBEIT IT SLOWLY.
AS IS SO OFTEN IS THE CASE...A STRONG LATITUDINAL H25 JET
CROSSING THE NORTHERN PACIFIC WILL PLOW ACROSS THE CANADIAN
ROCKIES AND ESTABLISH A BROAD DOWNSTREAM TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS TROUGH WILL FLATTEN THE PERTINACIOUS
SUB TROPICAL RIDGE...AND IN TIME WILL DIRECT PROGRESSIVELY COOLER
CANADIAN AIR SOUTHWARDS ACROSS THE LOWER 48. THIS COOLING WILL
INITIALLY ONLY TAKE OUR TEMPERATURES BACK TOWARDS NORMAL...BUT AS
WE HEAD IN TO THE WEEKEND...WE COULD EXPERIENCE A DAY OR TWO OF
FALL LIKE CONDITIONS.
AN INVERTED SFC TROUGH EXTENDING FROM THE UPPER GREAT LAKES TO
THE CENTRAL PLAINS LATE TUESDAY NIGHT WILL GRADUALLY EVOLVE INTO A
LEGITIMATE...ALBEIT WAVY...COLD FRONT ON WEDNESDAY AS IT WILL PUSH
SOUTHEAST ACROSS THE LOWER GREAT LAKES. THE OVERALL SYNOPTIC
FORCING WITH THE SLOW MOVING FRONTAL BOUNDARY IS NOT BEING
ADVERTISED AS BEING ALL THAT IMPRESSIVE...BUT IT WILL BE ENOUGH IN
COMBINATION WITH THE MID SUMMER LIKE THERMODYNAMIC ENVIRONMENT TO
PRODUCE INCREASINGLY NUMEROUS SHOWERS AND POTENTIALLY STRONG
THUNDERSTORMS.
ADDRESSING THE FORMER FIRST...AS EARLIER MENTIONED THE FRONTAL
BOUNDARY WILL STILL BE TAKING SHAPE DURING THE DAY WEDNESDAY AS IT
WILL BE PUSHING INTO OUR FORECAST AREA. TRUE FRONTOGENETIC FORCING
FROM THE FRONT WILL THUS BE GENERALLY WEAK...ALTHOUGH HGT FALLS
AND A 120KT H25 JET OVER NORTHERN QUEBEC WILL ADD SOME LARGE SCALE
SYNOPTIC LIFT BY PLACING OUR FORECAST AREA UNDER RR QUAD OF THE
JET ENTRANCE REGION. THERMODYNAMICALLY...OUR WARM HUMID AIRMASS
WILL ALREADY BE UNSTABLE. SBCAPES WILL ALREADY BE IN THE HUNDREDS
AS WE OPEN THE DAY...AND DIMINISHING MORNING SUNSHINE WILL ONLY
ADD TO THIS INSTABILITY...PARTICULARLY OVER PARTS OF THE SRN TIER
AND FINGER LAKES REGIONS WHERE MUCAPES COULD APPROACH 2000 J/KG.
MEANWHILE A SWATH OF TROPICAL MOISTURE TO THE TUNE OF 2 INCH PWAT
VALUES WILL STREAM ACROSS OUR REGION ALONG AND AHEAD OF THE SFC
BOUNDARY...SO THIS IN COMBINATION WITH THE SYNOPTIC FORCING AND
INSTABILITY COULD RESULT IN TORRENTIAL DOWNPOURS WITH SOME OF THE
CONVECTION. FORTUNATELY...THE REGION IS PARCHED FROM A GENERAL
LACK OF RAINFALL FROM THE PAST MONTH OR SO...AND GUIDANCE IS
SUGGESTING THAT CORFIDI VECTORS WILL LENGTHEN AS THE FRONT
APPROACHES. THIS WILL LESSEN THE RISK FOR WIDESPREAD HYDRO RELATED
PROBLEMS...BUT LOCAL ISSUES WILL STILL HAVE TO BE ADDRESSED GIVEN
THE SUB TROPICAL ENVIRONMENT. THE MENTION OF TORRENTIAL DOWNPOURS
HAS ALREADY BEEN ADDED TO THE HWO PRODUCT AND TO THE GRIDDED DATA
BASE...SO WILL CONTINUE.
ALONG WITH THE THREAT FOR LOCALLY HEAVY CONVECTIVE RAINS...THERE
WILL BE AN ISOLATED RISK FOR STRONG THUNDERSTORMS. THIS POTENTIAL
WILL BE ATTENUATED BY UNIMPRESSIVE MID LEVEL LAPSE RATES UNDER 6
DEG C/KM...BUT GIVEN BULK SHEAR VALUES OF 35 TO 40 KNOTS AND THE
UNCERTAINTY AS TO HOW MUCH SUNSHINE PARTS OF THE REGION RECEIVE...
WE WILL CONTINUE TO HIGHLIGHT THE CHANCE FOR GUSTY CONVECTIVE
WINDS.
CONSIDERING ALL OF THE ABOVE...WEDNESDAY SHOULD START OFF DRY
ACROSS OUR FORECAST AREA...BUT AS THE FRONT NEARS DURING THE
MIDDAY...CONVECTION WILL BEGIN TO BREAK OUT. THIS MAY BE HASTENED
ACROSS PARTS OF THE SRN TIER AND FINGER LAKES REGION WHERE A LAKE
BREEZE BOUNDARY COULD FOCUS AN INITIAL ROUND OF STORMS...THEN AS
THE FRONT SLOWLY CROSSES THE LOWER GREAT LAKES IN THE AFTERNOON
AND EVENING...THE GENERAL CONDITIONS WILL FURTHER DETERIORATE.
WILL MAINTAIN LIKELY POPS REGIONWIDE FOR THE LATE AFTERNOON...
BUT THE VAST MAJORITY OF THE DAY SHOULD BE RAIN FREE. OTHERWISE
WEDNESDAY WILL BE WARM AND HUMID WITH MAX TEMPS RANGING FROM THE
LOWER 80S OVER THE FAR WEST TO THE MID AND POSSIBLY UPPER 80S
ACROSS PARTS OF THE FINGER LAKES.
DURING THE COURSE OF WEDNESDAY NIGHT...THE FRONTAL BOUNDARY WILL
LAZILY CROSS OUR FORECAST AREA AS UPSTREAM SFC WAVES WILL RETARD
ITS FORWARD PROGRESS. THIS IS THE TIME PERIOD WHERE THE AXIS OF
THE DEEPEST MOISTURE WILL CROSS OUR FORECAST AREA. WHILE DIURNALLY
ENHANCED INSTABILITY WILL BE WANING...THE PASSAGE OF ANY WAVES
ALONG THE FRONTAL BOUNDARY COULD SYNOPTICALLY ENHANCE ANY SHOWERS
INTO A 2 TO THREE HOUR PERIOD OF STEADIER RAIN. THIS POTENTIAL
WILL BE GREATEST OVER THE SRN TIER AND FINGER LAKES REGION.
AGAIN...WE WILL BE FORTUNATE IN THAT WE HAVE VERY DRY ANTECEDENT
CONDITIONS.
ON THURSDAY...WEAK HIGH PRESSURE OVER LOWER MICHIGAN WILL
GRADUALLY BUILD ACROSS OUR FORECAST AREA WHILE THE FLEXUOUS
FRONTAL BOUNDARY WILL MAKE ITS WAY TO THE EAST COAST. SHOWERS...
THAT WILL BE MOST LIKELY EAST OF LINE FROM ROCHESTER TO
JAMESTOWN...WILL TAPER OFF FROM WEST TO EAST IN THE PROCESS.
SUNSHINE SHOULD RETURN IN FORCE TO THE NIAGARA FRONTIER AND PARTS
OF THE SRN TIER BY THE AFTERNOON...BUT THE IMPROVEMENT WILL TAKE
LONGER FURTHER EAST. IT WILL START TO FEEL MUCH MORE COMFORTABLE
AS WELL...AS THE FRESH AIRMASS WILL START TO SETTLE OVER THE
REGION WITH DEW POINTS OVER THE WESTERN COUNTIES STEADIER FALLING
THROUGH THE 50S. AFTER NEARLY TWO WEEKS OF AFTERNOON TEMPERATURES
IN THE 80S...MAX TEMPS ON THURSDAY SHOULD FINALLY RETURN TO THE
70S.
THE GRADUAL CLEARING PROCESS WILL CONTINUE THURSDAY NIGHT AS THE
LEADING EDGE OF HIGH PRESSURE WILL WORK ACROSS OUR FORECAST AREA.
ANY LEFTOVER SHOWERS OVER EASTERN SECTIONS SHOULD END DURING THE
EVENING WITH MUCH MORE COMFORTABLE SLEEPING CONDITIONS GAINING A
FOOTHOLD OVER THE ENTIRE FORECAST AREA. OVERNIGHT LOWS WILL
GENERALLY BE IN THE 50S...WITH THE RADIATIONAL COOLING PROBABLY
LEADING TO SOME VALLEY FOG ACROSS PARTS OF THE SRN TIER AND FINGER
LAKES REGIONS.
WHILE PLEASANT WEATHER IS EXPECTED ACROSS OUR REGION ON FRIDAY...
A MID LEVEL DISTURBANCE DIGGING INTO THE GREAT LAKES LONGWAVE
TROUGH WILL ENCOURAGE SOME `BAGGINESS` IN THE SFC PRESSURE FIELD
ACROSS THE UPPER OHIO VALLEY. THIS WILL BE THE BEGINNINGS OF WHAT
COULD POTENTIALLY BE A CLOSED LOW FOR OUR REGION DURING THE
UPCOMING WEEKEND. MORE ON THIS LOW CONFIDENCE EVENT IN THE LONG
TERM SECTION BELOW. GENERALLY PARTLY SUNNY SKIES CAN BE EXPECTED
ON FRIDAY WITH AFTERNOON TEMPERATURES IN THE 70S BEING ACCOMPANIED
BY COMFORTABLY LOW HUMIDITY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
ONCE AGAIN...THE MEDIUM RANGE GUIDANCE PACKAGES ARE VASTLY
DIFFERENT IN THEIR SOLUTIONS OVER THE LOWER GREAT LAKES IN THE
DAYS 5-7 PERIOD. BOTH THE GFS AND ECMWF OPERATIONAL MODELS ARE
STUBBORNLY HOLDING ONTO THE SAME SCENARIOS THAT THEY HAVE BEEN
PREACHING FOR THE PAST COUPLE DAYS... WITH THE LATTER DEPICTING
THE DEVELOPMENT OF A STACKED STORM SYSTEM OVER SOUTHERN ONTARIO
AND THE LOWER GREAT LAKES. NEEDLESS TO SAY...THIS WOULD BE A VERY
UNSETTLED SOLUTION FOR OUR FORECAST AREA WITH FAIRLY WIDESPREAD
FREQUENT SHOWERS.
BECAUSE OF THE DISPARITY WITHIN THE GUIDANCE PACKAGES...HAVE NO
CHOICE BUT TO KEEP THE LOW/SLGT CHC BROADBRUSH POPS THAT ARE IN
CONTINUITY IN PLACE THROUGH AT LEAST THE WEEKEND.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
A WEAK COLD FRONT WILL BRIEFLY STALL OUT ALONG OR SLIGHTLY NORTH
OF OUR NORTHERN PERIPHERY THIS MORNING...BEFORE LIFTING BACK NORTH
THIS AFTERNOON AS A WARM FRONT IN RESPONSE TO THE DEVELOPMENT OF
BROAD LOW PRESSURE OVER THE UPPER GREAT LAKES. THERE WILL BE A
CONTINUED RISK OF SCATTERED SHOWERS/THUNDERSTORMS AND ATTENDANT
BRIEF LOCALIZED RESTRICTIONS ALONG AND NEAR THIS BOUNDARY THROUGH
THE DAY...AND ALSO ALONG AND INLAND FROM A DEVELOPING LAKE ERIE
LAKE BREEZE BOUNDARY DURING THE AFTERNOON. OUTSIDE OF ANY SUCH
CONVECTION AND ANY EARLY MORNING SOUTHERN TIER VALLEY FOG...VFR
CONDITIONS SHOULD OTHERWISE PREVAIL.
TONIGHT...THE FRONTAL BOUNDARY WILL FINISH LIFTING OFF TO OUR
NORTH EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND
THE LOSS OF DAYTIME HEATING...ANY LINGERING CONVECTION/ATTENDANT
RESTRICTIONS ACROSS THE FINGER LAKES AND NORTH COUNTRY WILL COME
TO AN END THIS EVENING...LEAVING BEHIND LARGELY DRY/VFR CONDITIONS
FOR THE BALANCE OF THE NIGHTTIME HOURS.
OUTLOOK...
WEDNESDAY...MAINLY VFR INITIALLY...THEN SHOWERS AND THUNDERSTORMS
WITH ATTENDANT REDUCTIONS TO IFR/MVFR BECOMING LIKELY FOR WEDNESDAY
AFTERNOON AND EVENING.
THURSDAY...SCATTERED TO NUMEROUS SHOWERS TAPERING OFF WITH CONDITIONS
IMPROVING TO VFR.
FRIDAY...MAINLY VFR...EXCEPT IN POSSIBLE MORNING SOUTHERN TIER
VALLEY FOG.
SATURDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC COASTLINE WILL SLOWLY
DRIFT OFFSHORE THROUGH MIDWEEK. A STALLED OUT COLD FRONT DRAPED FROM
THE SAINT LAWRENCE VALLEY SOUTHWESTWARD ACROSS LAKE ONTARIO WILL LIFT
BACK NORTH OF THE REGION AS A WARM FRONT THIS AFTERNOON AND EVENING
IN RESPONSE TO DEVELOPING LOW PRESSURE ACROSS THE UPPER GREAT LAKES...
THEN THIS LATTER FEATURE WILL SLOWLY EASE ITS TRAILING COLD FRONT
ACROSS THE AREA WEDNESDAY AFTERNOON AND NIGHT.
THE INITIAL FRONTAL BOUNDARY WILL CONTINUE TO TRIGGER SCATTERED
SHOWERS AND THUNDERSTORMS AS IT LINGERS NEAR THE LOWER GREAT LAKES
THIS MORNING...WITH THESE THEN GRADUALLY DIMINISHING FROM SOUTHWEST
TO NORTHEAST THIS AFTERNOON AND EVENING AS THE BOUNDARY LIFTS AWAY
FROM OUR REGION. FOLLOWING ITS DEPARTURE...GENERALLY DRY CONDITIONS
ARE EXPECTED FOR THE BALANCE OF TONIGHT...BEFORE THE TRAILING COLD
FRONT BRINGS MORE NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES
THROUGH THE REGION WEDNESDAY AFTERNOON AND NIGHT.
WHILE ANY OF THE SHOWERS/STORMS COULD PRODUCE LOCALLY HIGHER WINDS AND
WAVES OVER THE NEXT COUPLE OF DAYS...IN GENERAL LIGHT TO MODEST WINDS
WILL PREVAIL ACROSS THE LOWER LAKES REGION THROUGH WEDNESDAY NIGHT...
ALONG WITH WAVES OF UNDER 3 FEET.
FOLLOWING THE PASSAGE OF THE FRONT...HIGH PRESSURE IS EXPECTED TO
BUILD ACROSS THE REGION THURSDAY AND FRIDAY WHILE BRINGING A RETURN
TO MORE SETTLED CONDITIONS...ALONG WITH CONTINUED LIGHT TO MODEST
WINDS AND MINIMAL WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...JJR
MARINE...JJR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
504 AM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC COAST WILL CONTINUE TO BRING
MIDSUMMERLIKE CONDITIONS TO THE REGION THROUGH THE FIRST HALF OF
WEDNESDAY...BEFORE A COLD FRONT CROSSES OUR REGION BETWEEN LATER
WEDNESDAY AND WEDNESDAY NIGHT. THIS FRONT WILL BE ACCOMPANIED BY
NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES THROUGH...AND WILL
BE FOLLOWED BY PROGRESSIVELY COOLER WEATHER DURING THE REMAINDER
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 08Z...REGIONAL SURFACE OBSERVATIONS SUGGEST THAT THE WEAK
COLD FRONTAL BOUNDARY EXTENDS FROM THE SAINT LAWRENCE VALLEY
ACROSS NORTHERN LAKE ONTARIO TO THE GREATER TORONTO AREA...AND
THEN ON ACROSS SOUTHWESTERN ONTARIO. ALONG AND NEAR THIS
BOUNDARY...REGIONAL RADARS CONTINUE TO DEPICT AN ELONGATED SWATH
OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS.
DURING THE COURSE OF TODAY...THE WEAK COLD FRONT WILL BRIEFLY
STALL OUT ALONG OR SLIGHTLY NORTH OF OUR NORTHERN PERIPHERY THIS
MORNING... BEFORE LIFTING BACK NORTH THIS AFTERNOON AS A WARM
FRONT IN RESPONSE TO THE DEVELOPMENT OF BROAD LOW PRESSURE OVER
THE UPPER GREAT LAKES. ALONG AND NEAR THIS BOUNDARY...THERE WILL
BE A CONTINUED RISK OF SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
THE DAY...WITH THIS RISK LYING ROUGHLY FROM THE NYS THRUWAY
CORRIDOR NORTHWARD THROUGH LATE THIS MORNING...THEN DIMINISHING
FROM SOUTHWEST TO NORTHEAST LATE THIS MORNING AND THIS AFTERNOON
AS THE FRONT BEGINS LIFTING BACK NORTH.
IN ADDITION TO ANY FRONTAL CONVECTION...THE COMBINATION OF
DIURNAL HEATING OF OUR VERY WARM AND HUMID AIRMASS AND
REDEVELOPING LAKE BREEZE BOUNDARIES MAY ALSO LEAD TO THE
DEVELOPMENT OF A SECOND REGION OF ISOLATED TO SCATTERED CONVECTION
ACROSS AREAS SOUTH OF LAKE ONTARIO THIS AFTERNOON...WITH THIS
PRIMARILY FOCUSED FROM INTERIOR PORTIONS OF THE SOUTHERN TIER AND
GENESEE VALLEY EASTWARD ACROSS THE FINGER LAKES.
WITH ALL OF THE ABOVE IN MIND...HAVE CONTINUED TO DEPICT A
GENERAL SOUTHWEST-NORTHEAST GRADIENT IN PRECIPITATION
PROBABILITIES FOR TODAY...WITH THESE RANGING FROM HIGH CHANCE
ACROSS THE SAINT LAWRENCE VALLEY AND NORTH COUNTRY...TO BELOW
SLIGHT CHANCE IN AN EXPECTED REGION OF LAKE SHADOWING IMMEDIATELY
EAST OF LAKE ERIE.
OUTSIDE OF THE AFOREMENTIONED CONVECTION...DRY WEATHER AND
MIDSUMMERLIKE WARMTH AND HUMIDITY SHOULD AGAIN PREVAIL ACROSS OUR
REGION TODAY. SURFACE DEWPOINTS WILL RANGE FROM THE LOWER 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO NEAR 70 ALONG THE
STALLED/RETREATING FRONTAL BOUNDARY...WHILE 850 MB TEMPS OF +16C
TO +19C WILL SUPPORT HIGH TEMPERATURES RANGING FROM THE LOWER 80S
ACROSS THE NORTH COUNTRY TO THE MID AND UPPER 80S ACROSS MOST OF
THE REST OF THE REGION...ALONG WITH SOME 90 DEGREE READINGS ACROSS
THE NORMAL WARM SPOTS OF THE GENESEE VALLEY/FINGER LAKES.
TONIGHT...THE WARM FRONT WILL FINISH LIFTING OFF TO OUR NORTH
EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE
LOSS OF DAYTIME HEATING...ANY LINGERING CONVECTION ACROSS THE
FINGER LAKES AND NORTH COUNTRY WILL COME TO AN END THIS
EVENING...LEAVING BEHIND LARGELY DRY WEATHER FOR THE BALANCE OF
THE NIGHTTIME HOURS AS OUR REGION WILL BE FIRMLY ENTRENCHED WITHIN
THE WARM SECTOR OF LOW PRESSURE LIFTING BY WELL TO OUR NORTHWEST.
THUS...WE CAN EXPECT YET ANOTHER UNSEASONABLY WARM NIGHT ACROSS
OUR REGION...WITH OVERNIGHT LOWS AGAIN RANGING FROM THE MID 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO THE LOWER 70S
ACROSS THE LAKE PLAINS...OR LEVELS THAT WILL BE NOT THAT FAR OFF
FROM NORMAL HIGH TEMPERATURES FOR EARLY SEPTEMBER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TEMPERATURES WILL RETURN TO NEAR NORMAL LEVELS ACROSS THE LOWER
GREAT LAKES DURING THIS PERIOD...AS THE UPPER LEVEL FLOW ACROSS
NORTH AMERICA WILL FEATURE AN AMPLIFYING TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS WILL BE SIGNIFICANT CHANGE FROM THE
FIRST WEEK OF SEPTEMBER WHEN A PERSISTENT SUB-TROPICAL RIDGE
DOMINATED THE EASTERN HALF OF THE COUNTRY. WHILE THE RIDGE WAS NOT
OVERLY IMPRESSIVE `ON PAPER`...ITS STAYING POWER FOR THIS TIME OF
YEAR ALLOWED FOR ANOMALOUSLY WARM AIR AND PLENTY OF GULF HUMIDITY
TO CREATE THE WARMEST STRETCH OF WEATHER OUR REGION EXPERIENCED
ALL SUMMER. WITH THE PASSING OF THE LAST SUMMER HOLIDAY...MOTHER
NATURE WILL ALSO TURN THE PAGE...ALBEIT IT SLOWLY.
AS IS SO OFTEN IS THE CASE...A STRONG LATITUDINAL H25 JET
CROSSING THE NORTHERN PACIFIC WILL PLOW ACROSS THE CANADIAN
ROCKIES AND ESTABLISH A BROAD DOWNSTREAM TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS TROUGH WILL FLATTEN THE PERTINACIOUS
SUB TROPICAL RIDGE...AND IN TIME WILL DIRECT PROGRESSIVELY COOLER
CANADIAN AIR SOUTHWARDS ACROSS THE LOWER 48. THIS COOLING WILL
INITIALLY ONLY TAKE OUR TEMPERATURES BACK TOWARDS NORMAL...BUT AS
WE HEAD IN TO THE WEEKEND...WE COULD EXPERIENCE A DAY OR TWO OF
FALL LIKE CONDITIONS.
AN INVERTED SFC TROUGH EXTENDING FROM THE UPPER GREAT LAKES TO
THE CENTRAL PLAINS LATE TUESDAY NIGHT WILL GRADUALLY EVOLVE INTO A
LEGITIMATE...ALBEIT WAVY...COLD FRONT ON WEDNESDAY AS IT WILL PUSH
SOUTHEAST ACROSS THE LOWER GREAT LAKES. THE OVERALL SYNOPTIC
FORCING WITH THE SLOW MOVING FRONTAL BOUNDARY IS NOT BEING
ADVERTISED AS BEING ALL THAT IMPRESSIVE...BUT IT WILL BE ENOUGH IN
COMBINATION WITH THE MID SUMMER LIKE THERMODYNAMIC ENVIRONMENT TO
PRODUCE INCREASINGLY NUMEROUS SHOWERS AND POTENTIALLY STRONG
THUNDERSTORMS.
ADDRESSING THE FORMER FIRST...AS EARLIER MENTIONED THE FRONTAL
BOUNDARY WILL STILL BE TAKING SHAPE DURING THE DAY WEDNESDAY AS IT
WILL BE PUSHING INTO OUR FORECAST AREA. TRUE FRONTOGENETIC FORCING
FROM THE FRONT WILL THUS BE GENERALLY WEAK...ALTHOUGH HGT FALLS
AND A 120KT H25 JET OVER NORTHERN QUEBEC WILL ADD SOME LARGE SCALE
SYNOPTIC LIFT BY PLACING OUR FORECAST AREA UNDER RR QUAD OF THE
JET ENTRANCE REGION. THERMODYNAMICALLY...OUR WARM HUMID AIRMASS
WILL ALREADY BE UNSTABLE. SBCAPES WILL ALREADY BE IN THE HUNDREDS
AS WE OPEN THE DAY...AND DIMINISHING MORNING SUNSHINE WILL ONLY
ADD TO THIS INSTABILITY...PARTICULARLY OVER PARTS OF THE SRN TIER
AND FINGER LAKES REGIONS WHERE MUCAPES COULD APPROACH 2000 J/KG.
MEANWHILE A SWATH OF TROPICAL MOISTURE TO THE TUNE OF 2 INCH PWAT
VALUES WILL STREAM ACROSS OUR REGION ALONG AND AHEAD OF THE SFC
BOUNDARY...SO THIS IN COMBINATION WITH THE SYNOPTIC FORCING AND
INSTABILITY COULD RESULT IN TORRENTIAL DOWNPOURS WITH SOME OF THE
CONVECTION. FORTUNATELY...THE REGION IS PARCHED FROM A GENERAL
LACK OF RAINFALL FROM THE PAST MONTH OR SO...AND GUIDANCE IS
SUGGESTING THAT CORFIDI VECTORS WILL LENGTHEN AS THE FRONT
APPROACHES. THIS WILL LESSEN THE RISK FOR WIDESPREAD HYDRO RELATED
PROBLEMS...BUT LOCAL ISSUES WILL STILL HAVE TO BE ADDRESSED GIVEN
THE SUB TROPICAL ENVIRONMENT. THE MENTION OF TORRENTIAL DOWNPOURS
HAS ALREADY BEEN ADDED TO THE HWO PRODUCT AND TO THE GRIDDED DATA
BASE...SO WILL CONTINUE.
ALONG WITH THE THREAT FOR LOCALLY HEAVY CONVECTIVE RAINS...THERE
WILL BE AN ISOLATED RISK FOR STRONG THUNDERSTORMS. THIS POTENTIAL
WILL BE ATTENUATED BY UNIMPRESSIVE MID LEVEL LAPSE RATES UNDER 6
DEG C/KM...BUT GIVEN BULK SHEAR VALUES OF 35 TO 40 KNOTS AND THE
UNCERTAINTY AS TO HOW MUCH SUNSHINE PARTS OF THE REGION RECEIVE...
WE WILL CONTINUE TO HIGHLIGHT THE CHANCE FOR GUSTY CONVECTIVE
WINDS.
CONSIDERING ALL OF THE ABOVE...WEDNESDAY SHOULD START OFF DRY
ACROSS OUR FORECAST AREA...BUT AS THE FRONT NEARS DURING THE
MIDDAY...CONVECTION WILL BEGIN TO BREAK OUT. THIS MAY BE HASTENED
ACROSS PARTS OF THE SRN TIER AND FINGER LAKES REGION WHERE A LAKE
BREEZE BOUNDARY COULD FOCUS AN INITIAL ROUND OF STORMS...THEN AS
THE FRONT SLOWLY CROSSES THE LOWER GREAT LAKES IN THE AFTERNOON
AND EVENING...THE GENERAL CONDITIONS WILL FURTHER DETERIORATE.
WILL MAINTAIN LIKELY POPS REGIONWIDE FOR THE LATE AFTERNOON.
OTHERWISE...WEDNESDAY WILL BE WARM AND HUMID WITH MAX TEMPS
RANGING FROM THE LOWER 80S OVER THE FAR WEST TO THE MID AND
POSSIBLY UPPER 80S ACROSS PARTS OF THE FINGER LAKES.
DURING THE COURSE OF WEDNESDAY NIGHT...THE FRONTAL BOUNDARY WILL
LAZILY CROSS OUR FORECAST AREA AS UPSTREAM SFC WAVES WILL RETARD
ITS FORWARD PROGRESS. THIS IS THE TIME PERIOD WHERE THE AXIS OF
THE DEEPEST MOISTURE WILL CROSS OUR FORECAST AREA. WHILE DIURNALLY
ENHANCED INSTABILITY WILL BE WANING...THE PASSAGE OF ANY WAVES
ALONG THE FRONTAL BOUNDARY COULD SYNOPTICALLY ENHANCE ANY SHOWERS
INTO A 2 TO THREE HOUR PERIOD OF STEADIER RAIN. THIS POTENTIAL
WILL BE GREATEST OVER THE SRN TIER AND FINGER LAKES REGION.
AGAIN...WE WILL BE FORTUNATE IN THAT WE HAVE VERY DRY ANTECEDENT
CONDITIONS.
ON THURSDAY...WEAK HIGH PRESSURE OVER LOWER MICHIGAN WILL
GRADUALLY BUILD ACROSS OUR FORECAST AREA WHILE THE FLEXUOUS
FRONTAL BOUNDARY WILL MAKE ITS WAY TO THE EAST COAST. SHOWERS...
THAT WILL BE MOST LIKELY EAST OF LINE FROM ROCHESTER TO
JAMESTOWN...WILL TAPER OFF FROM WEST TO EAST IN THE PROCESS.
SUNSHINE SHOULD RETURN IN FORCE TO THE NIAGARA FRONTIER AND PARTS
OF THE SRN TIER BY THE AFTERNOON...BUT THE IMPROVEMENT WILL TAKE
LONGER FURTHER EAST. IT WILL START TO FEEL MUCH MORE COMFORTABLE
AS WELL...AS THE FRESH AIRMASS WILL START TO SETTLE OVER THE
REGION WITH DEW POINTS OVER THE WESTERN COUNTIES STEADIER FALLING
THROUGH THE 50S. AFTER NEARLY TWO WEEKS OF AFTERNOON TEMPERATURES
IN THE 80S...MAX TEMPS ON THURSDAY SHOULD FINALLY RETURN TO THE
70S.
THE GRADUAL CLEARING PROCESS WILL CONTINUE THURSDAY NIGHT AS THE
LEADING EDGE OF HIGH PRESSURE WILL WORK ACROSS OUR FORECAST AREA.
ANY LEFTOVER SHOWERS OVER EASTERN SECTIONS SHOULD END DURING THE
EVENING WITH MUCH MORE COMFORTABLE SLEEPING CONDITIONS GAINING A
FOOTHOLD OVER THE ENTIRE FORECAST AREA. OVERNIGHT LOWS WILL
GENERALLY BE IN THE 50S...WITH THE RADIATIONAL COOLING PROBABLY
LEADING TO SOME VALLEY FOG ACROSS PARTS OF THE SRN TIER AND FINGER
LAKES REGIONS.
WHILE PLEASANT WEATHER IS EXPECTED ACROSS OUR REGION ON FRIDAY...
A MID LEVEL DISTURBANCE DIGGING INTO THE GREAT LAKES LONGWAVE
TROUGH WILL ENCOURAGE SOME `BAGGINESS` IN THE SFC PRESSURE FIELD
ACROSS THE UPPER OHIO VALLEY. THIS WILL BE THE BEGINNINGS OF WHAT
COULD POTENTIALLY BE A CLOSED LOW FOR OUR REGION DURING THE
UPCOMING WEEKEND. MORE ON THIS LOW CONFIDENCE EVENT IN THE LONG
TERM SECTION BELOW. GENERALLY PARTLY SUNNY SKIES CAN BE EXPECTED
ON FRIDAY WITH AFTERNOON TEMPERATURES IN THE 70S BEING ACCOMPANIED
BY COMFORTABLY LOW HUMIDITY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
ONCE AGAIN...THE MEDIUM RANGE GUIDANCE PACKAGES ARE VASTLY
DIFFERENT IN THEIR SOLUTIONS OVER THE LOWER GREAT LAKES IN THE
DAYS 5-7 PERIOD. BOTH THE GFS AND ECMWF OPERATIONAL MODELS ARE
STUBBORNLY HOLDING ONTO THE SAME SCENARIOS THAT THEY HAVE BEEN
PREACHING FOR THE PAST COUPLE DAYS... WITH THE LATTER DEPICTING
THE DEVELOPMENT OF A STACKED STORM SYSTEM OVER SOUTHERN ONTARIO
AND THE LOWER GREAT LAKES. NEEDLESS TO SAY...THIS WOULD BE A VERY
UNSETTLED SOLUTION FOR OUR FORECAST AREA WITH FAIRLY WIDESPREAD
FREQUENT SHOWERS.
BECAUSE OF THE DISPARITY WITHIN THE GUIDANCE PACKAGES...HAVE NO
CHOICE BUT TO KEEP THE LOW/SLGT CHC BROADBRUSH POPS THAT ARE IN
CONTINUITY IN PLACE THROUGH AT LEAST THE WEEKEND.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
A WEAK COLD FRONT WILL BRIEFLY STALL OUT ALONG OR SLIGHTLY NORTH
OF OUR NORTHERN PERIPHERY THIS MORNING...BEFORE LIFTING BACK NORTH
THIS AFTERNOON AS A WARM FRONT IN RESPONSE TO THE DEVELOPMENT OF
BROAD LOW PRESSURE OVER THE UPPER GREAT LAKES. THERE WILL BE A
CONTINUED RISK OF SCATTERED SHOWERS/THUNDERSTORMS AND ATTENDANT
BRIEF LOCALIZED RESTRICTIONS ALONG AND NEAR THIS BOUNDARY THROUGH
THE DAY...AND ALSO ALONG AND INLAND FROM A DEVELOPING LAKE ERIE
LAKE BREEZE BOUNDARY DURING THE AFTERNOON. OUTSIDE OF ANY SUCH
CONVECTION AND ANY EARLY MORNING SOUTHERN TIER VALLEY FOG...VFR
CONDITIONS SHOULD OTHERWISE PREVAIL.
TONIGHT...THE FRONTAL BOUNDARY WILL FINISH LIFTING OFF TO OUR
NORTH EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND
THE LOSS OF DAYTIME HEATING...ANY LINGERING CONVECTION/ATTENDANT
RESTRICTIONS ACROSS THE FINGER LAKES AND NORTH COUNTRY WILL COME
TO AN END THIS EVENING...LEAVING BEHIND LARGELY DRY/VFR CONDITIONS
FOR THE BALANCE OF THE NIGHTTIME HOURS.
OUTLOOK...
WEDNESDAY...MAINLY VFR INITIALLY...THEN SHOWERS AND THUNDERSTORMS
WITH ATTENDANT REDUCTIONS TO IFR/MVFR BECOMING LIKELY FOR WEDNESDAY
AFTERNOON AND EVENING.
THURSDAY...SCATTERED TO NUMEROUS SHOWERS TAPERING OFF WITH CONDITIONS
IMPROVING TO VFR.
FRIDAY...MAINLY VFR...EXCEPT IN POSSIBLE MORNING SOUTHERN TIER
VALLEY FOG.
SATURDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC COASTLINE WILL SLOWLY
DRIFT OFFSHORE THROUGH MIDWEEK. A STALLED OUT COLD FRONT DRAPED FROM
THE SAINT LAWRENCE VALLEY SOUTHWESTWARD ACROSS LAKE ONTARIO WILL LIFT
BACK NORTH OF THE REGION AS A WARM FRONT THIS AFTERNOON AND EVENING
IN RESPONSE TO DEVELOPING LOW PRESSURE ACROSS THE UPPER GREAT LAKES...
THEN THIS LATTER FEATURE WILL SLOWLY EASE ITS TRAILING COLD FRONT
ACROSS THE AREA WEDNESDAY AFTERNOON AND NIGHT.
THE INITIAL FRONTAL BOUNDARY WILL CONTINUE TO TRIGGER SCATTERED
SHOWERS AND THUNDERSTORMS AS IT LINGERS NEAR THE LOWER GREAT LAKES
THIS MORNING...WITH THESE THEN GRADUALLY DIMINISHING FROM SOUTHWEST
TO NORTHEAST THIS AFTERNOON AND EVENING AS THE BOUNDARY LIFTS AWAY
FROM OUR REGION. FOLLOWING ITS DEPARTURE...GENERALLY DRY CONDITIONS
ARE EXPECTED FOR THE BALANCE OF TONIGHT...BEFORE THE TRAILING COLD
FRONT BRINGS MORE NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES
THROUGH THE REGION WEDNESDAY AFTERNOON AND NIGHT.
WHILE ANY OF THE SHOWERS/STORMS COULD PRODUCE LOCALLY HIGHER WINDS AND
WAVES OVER THE NEXT COUPLE OF DAYS...IN GENERAL LIGHT TO MODEST WINDS
WILL PREVAIL ACROSS THE LOWER LAKES REGION THROUGH WEDNESDAY NIGHT...
ALONG WITH WAVES OF UNDER 3 FEET.
FOLLOWING THE PASSAGE OF THE FRONT...HIGH PRESSURE IS EXPECTED TO
BUILD ACROSS THE REGION THURSDAY AND FRIDAY WHILE BRINGING A RETURN
TO MORE SETTLED CONDITIONS...ALONG WITH CONTINUED LIGHT TO MODEST
WINDS AND MINIMAL WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...JJR
MARINE...JJR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
414 AM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC COAST WILL CONTINUE TO BRING
MIDSUMMERLIKE CONDITIONS TO THE REGION THROUGH THE FIRST HALF OF
WEDNESDAY...BEFORE A COLD FRONT CROSSES OUR REGION BETWEEN LATER
WEDNESDAY AND WEDNESDAY NIGHT. THIS FRONT WILL BE ACCOMPANIED BY
NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES THROUGH...AND WILL
BE FOLLOWED BY PROGRESSIVELY COOLER WEATHER DURING THE REMAINDER
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 08Z...REGIONAL SURFACE OBSERVATIONS SUGGEST THAT THE WEAK
COLD FRONTAL BOUNDARY EXTENDS FROM THE SAINT LAWRENCE VALLEY
ACROSS NORTHERN LAKE ONTARIO TO THE GREATER TORONTO AREA...AND
THEN ON ACROSS SOUTHWESTERN ONTARIO. ALONG AND NEAR THIS
BOUNDARY...REGIONAL RADARS CONTINUE TO DEPICT AN ELONGATED SWATH
OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS.
DURING THE COURSE OF TODAY...THE WEAK COLD FRONT WILL BRIEFLY
STALL OUT ALONG OR SLIGHTLY NORTH OF OUR NORTHERN PERIPHERY THIS
MORNING... BEFORE LIFTING BACK NORTH THIS AFTERNOON AS A WARM
FRONT IN RESPONSE TO THE DEVELOPMENT OF BROAD LOW PRESSURE OVER
THE UPPER GREAT LAKES. ALONG AND NEAR THIS BOUNDARY...THERE WILL
BE A CONTINUED RISK OF SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
THE DAY...WITH THIS RISK LYING ROUGHLY FROM THE NYS THRUWAY
CORRIDOR NORTHWARD THROUGH LATE THIS MORNING...THEN DIMINISHING
FROM SOUTHWEST TO NORTHEAST LATE THIS MORNING AND THIS AFTERNOON
AS THE FRONT BEGINS LIFTING BACK NORTH.
IN ADDITION TO ANY FRONTAL CONVECTION...THE COMBINATION OF
DIURNAL HEATING OF OUR VERY WARM AND HUMID AIRMASS AND
REDEVELOPING LAKE BREEZE BOUNDARIES MAY ALSO LEAD TO THE
DEVELOPMENT OF A SECOND REGION OF ISOLATED TO SCATTERED CONVECTION
ACROSS AREAS SOUTH OF LAKE ONTARIO THIS AFTERNOON...WITH THIS
PRIMARILY FOCUSED FROM INTERIOR PORTIONS OF THE SOUTHERN TIER AND
GENESEE VALLEY EASTWARD ACROSS THE FINGER LAKES.
WITH ALL OF THE ABOVE IN MIND...HAVE CONTINUED TO DEPICT A
GENERAL SOUTHWEST-NORTHEAST GRADIENT IN PRECIPITATION
PROBABILITIES FOR TODAY...WITH THESE RANGING FROM HIGH CHANCE
ACROSS THE SAINT LAWRENCE VALLEY AND NORTH COUNTRY...TO BELOW
SLIGHT CHANCE IN AN EXPECTED REGION OF LAKE SHADOWING IMMEDIATELY
EAST OF LAKE ERIE.
OUTSIDE OF THE AFOREMENTIONED CONVECTION...DRY WEATHER AND
MIDSUMMERLIKE WARMTH AND HUMIDITY SHOULD AGAIN PREVAIL ACROSS OUR
REGION TODAY. SURFACE DEWPOINTS WILL RANGE FROM THE LOWER 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO NEAR 70 ALONG THE
STALLED/RETREATING FRONTAL BOUNDARY...WHILE 850 MB TEMPS OF +16C
TO +19C WILL SUPPORT HIGH TEMPERATURES RANGING FROM THE LOWER 80S
ACROSS THE NORTH COUNTRY TO THE MID AND UPPER 80S ACROSS MOST OF
THE REST OF THE REGION...ALONG WITH SOME 90 DEGREE READINGS ACROSS
THE NORMAL WARM SPOTS OF THE GENESEE VALLEY/FINGER LAKES.
TONIGHT...THE WARM FRONT WILL FINISH LIFTING OFF TO OUR NORTH
EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE
LOSS OF DAYTIME HEATING...ANY LINGERING CONVECTION ACROSS THE
FINGER LAKES AND NORTH COUNTRY WILL COME TO AN END THIS
EVENING...LEAVING BEHIND LARGELY DRY WEATHER FOR THE BALANCE OF
THE NIGHTTIME HOURS AS OUR REGION WILL BE FIRMLY ENTRENCHED WITHIN
THE WARM SECTOR OF LOW PRESSURE LIFTING BY WELL TO OUR NORTHWEST.
THUS...WE CAN EXPECT YET ANOTHER UNSEASONABLY WARM NIGHT ACROSS
OUR REGION...WITH OVERNIGHT LOWS AGAIN RANGING FROM THE MID 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO THE LOWER 70S
ACROSS THE LAKE PLAINS...OR LEVELS THAT WILL BE NOT THAT FAR OFF
FROM NORMAL HIGH TEMPERATURES FOR EARLY SEPTEMBER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TEMPERATURES WILL RETURN TO NEAR NORMAL LEVELS ACROSS THE LOWER
GREAT LAKES DURING THIS PERIOD...AS THE UPPER LEVEL FLOW ACROSS
NORTH AMERICA WILL FEATURE AN AMPLIFYING TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS WILL BE SIGNIFICANT CHANGE FROM THE
FIRST WEEK OF SEPTEMBER WHEN A PERSISTENT SUB-TROPICAL RIDGE
DOMINATED THE EASTERN HALF OF THE COUNTRY. WHILE THE RIDGE WAS NOT
OVERLY IMPRESSIVE `ON PAPER`...ITS STAYING POWER FOR THIS TIME OF
YEAR ALLOWED FOR ANOMALOUSLY WARM AIR AND PLENTY OF GULF HUMIDITY
TO CREATE THE WARMEST STRETCH OF WEATHER OUR REGION EXPERIENCED
ALL SUMMER. WITH THE PASSING OF THE LAST SUMMER HOLIDAY...MOTHER
NATURE WILL ALSO TURN THE PAGE...ALBEIT IT SLOWLY.
AS IS SO OFTEN IS THE CASE...A STRONG LATITUDINAL H25 JET
CROSSING THE NORTHERN PACIFIC WILL PLOW ACROSS THE CANADIAN
ROCKIES AND ESTABLISH A BROAD DOWNSTREAM TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS TROUGH WILL FLATTEN THE PERTINACIOUS
SUB TROPICAL RIDGE...AND IN TIME WILL DIRECT PROGRESSIVELY COOLER
CANADIAN AIR SOUTHWARDS ACROSS THE LOWER 48. THIS COOLING WILL
INITIALLY ONLY TAKE OUR TEMPERATURES BACK TOWARDS NORMAL...BUT AS
WE HEAD IN TO THE WEEKEND...WE COULD EXPERIENCE A DAY OR TWO OF
FALL LIKE CONDITIONS.
AN INVERTED SFC TROUGH EXTENDING FROM THE UPPER GREAT LAKES TO
THE CENTRAL PLAINS LATE TUESDAY NIGHT WILL GRADUALLY EVOLVE INTO A
LEGITIMATE...ALBEIT WAVY...COLD FRONT ON WEDNESDAY AS IT WILL PUSH
SOUTHEAST ACROSS THE LOWER GREAT LAKES. THE OVERALL SYNOPTIC
FORCING WITH THE SLOW MOVING FRONTAL BOUNDARY IS NOT BEING
ADVERTISED AS BEING ALL THAT IMPRESSIVE...BUT IT WILL BE ENOUGH IN
COMBINATION WITH THE MID SUMMER LIKE THERMODYNAMIC ENVIRONMENT TO
PRODUCE INCREASINGLY NUMEROUS SHOWERS AND POTENTIALLY STRONG
THUNDERSTORMS.
ADDRESSING THE FORMER FIRST...AS EARLIER MENTIONED THE FRONTAL
BOUNDARY WILL STILL BE TAKING SHAPE DURING THE DAY WEDNESDAY AS IT
WILL BE PUSHING INTO OUR FORECAST AREA. TRUE FRONTOGENETIC FORCING
FROM THE FRONT WILL THUS BE GENERALLY WEAK...ALTHOUGH HGT FALLS
AND A 120KT H25 JET OVER NORTHERN QUEBEC WILL ADD SOME LARGE SCALE
SYNOPTIC LIFT BY PLACING OUR FORECAST AREA UNDER RR QUAD OF THE
JET ENTRANCE REGION. THERMODYNAMICALLY...OUR WARM HUMID AIRMASS
WILL ALREADY BE UNSTABLE. SBCAPES WILL ALREADY BE IN THE HUNDREDS
AS WE OPEN THE DAY...AND DIMINISHING MORNING SUNSHINE WILL ONLY
ADD TO THIS INSTABILITY...PARTICULARLY OVER PARTS OF THE SRN TIER
AND FINGER LAKES REGIONS WHERE MUCAPES COULD APPROACH 2000 J/KG.
MEANWHILE A SWATH OF TROPICAL MOISTURE TO THE TUNE OF 2 INCH PWAT
VALUES WILL STREAM ACROSS OUR REGION ALONG AND AHEAD OF THE SFC
BOUNDARY...SO THIS IN COMBINATION WITH THE SYNOPTIC FORCING AND
INSTABILITY COULD RESULT IN TORRENTIAL DOWNPOURS WITH SOME OF THE
CONVECTION. FORTUNATELY...THE REGION IS PARCHES FROM A GENERAL
LACK OF RAINFALL FROM THE PAST MONTH OR SO...AND GUIDANCE IS
SUGGESTING THAT CORFIDI VECTORS WILL LENGTHEN AS THE FRONT
APPROACHES. THIS WILL LESSEN THE RISK FOR WIDESPREAD HYDRO RELATED
PROBLEMS...BUT LOCAL ISSUES WILL STILL HAVE TO BE ADDRESSED GIVEN
THE SUB TROPICAL ENVIRONMENT. THE MENTION OF TORRENTIAL DOWNPOURS
HAS ALREADY BEEN ADDED TO THE HWO PRODUCE AND TO THE GRIDDED DATA
BASE...SO WILL CONTINUE.
ALONG WITH THE THREAT FOR LOCALLY HEAVY CONVECTIVE RAINS...THERE
WILL BE AN ISOLATED RISK FOR STRONG THUNDERSTORMS. THIS POTENTIAL
WILL BE ATTENUATED BY UNIMPRESSIVE MID LEVEL LAPSE RATES UNDER 6
DEG C/KM...BUT GIVEN BULK SHEAR VALUES OF 35 TO 40 KNOTS AND THE
UNCERTAINTY AS TO HOW MUCH SUNSHINE PARTS OF THE REGION RECEIVE...
WE WILL CONTINUE TO HIGHLIGHT THE CHANCE FOR GUSTY CONVECTIVE
WINDS.
CONSIDERING ALL OF THE ABOVE...WEDNESDAY SHOULD START OFF DRY
ACROSS OUR FORECAST AREA...BUT AS THE FRONT NEARS DURING THE
MIDDAY... CONVECTION WILL BEGIN TO BREAK OUT. THIS MAY BE HASTENED
ACROSS PARTS OF THE SRN TIER AND FINGER LAKES REGION WHERE A LAKE
BREEZE BOUNDARY COULD FOCUS AN INITIAL ROUND OF STORMS...THEN AS
THE FRONT SLOWLY CROSSES THE LOWER GREAT LAKES IN THE AFTERNOON
AND EVENING... THE GENERAL CONDITIONS WILL FURTHER DETERIORATE.
WILL MAINTAIN LIKELY POPS REGIONWIDE FOR THE LATE AFTERNOON.
OTHERWISE...WEDNESDAY WILL BE WARM AND HUMID WITH MAX TEMPS
RANGING FROM THE LOWER 80S OVER THE FAR WEST TO THE MID AND
POSSIBLY UPPER 80S ACROSS PARTS OF THE FINGER LAKES.
DURING THE COURSE OF WEDNESDAY NIGHT...THE FRONTAL BOUNDARY WILL
LAZILY CROSS OUR FORECAST AREA AS UPSTREAM SFC WAVES WILL RETARD
ITS FORWARD PROGRESS. THIS IS THE TIME PERIOD WHERE THE AXIS OF
THE DEEPEST MOISTURE WILL CROSS OUR FORECAST AREA. WHILE DIURNALLY
ENHANCED INSTABILITY WILL BE WANING...THE PASSAGE OF ANY WAVES
ALONG THE FRONTAL BOUNDARY COULD SYNOPTICALLY ENHANCE ANY SHOWERS
INTO A 2 TO THREE HOUR PERIOD OF STEADIER RAIN. THIS POTENTIAL
WILL BE GREATEST OVER THE SRN TIER AND FINGER LAKES REGION.
AGAIN...WE WILL BE FORTUNATE IN THAT WE HAVE VERY DRY ANTECEDENT
CONDITIONS.
ON THURSDAY...WEAK HIGH PRESSURE OVER LOWER MICHIGAN WILL
GRADUALLY BUILD ACROSS OUR FORECAST AREA WHILE THE FLEXUOUS
FRONTAL BOUNDARY WILL MAKE ITS WAY TO THE EAST COAST. SHOWERS...
THAT WILL BE MOST LIKELY EAST OF LINE FROM ROCHESTER TO
JAMESTOWN...WILL TAPER OFF FROM WEST TO EAST IN THE PROCESS.
SUNSHINE SHOULD RETURN IN FORCE TO THE NIAGARA FRONTIER AND PARTS
OF THE SRN TIER BY THE AFTERNOON... BUT THE IMPROVEMENT WILL TAKE
LONGER FURTHER EAST. IT WILL START TO FEEL MUCH MORE COMFORTABLE
AS WELL...AS THE FRESH AIRMASS WILL START TO SETTLE OVER THE
REGION WITH DEW POINTS OVER THE WESTERN COUNTIES STEADIER FALLING
THROUGH THE 50S. AFTER NEARLY TWO WEEKS OF AFTERNOON TEMPERATURES
IN THE 80S...MAX TEMPS ON THURSDAY SHOULD FINALLY RETURN TO THE
70S.
THE GRADUAL CLEARING PROCESS WILL CONTINUE THURSDAY NIGHT AS THE
LEADING EDGE OF HIGH PRESSURE WILL WORK ACROSS OUR FORECAST AREA.
ANY LEFTOVER SHOWERS OVER EASTERN SECTIONS SHOULD END DURING THE
EVENING WITH MUCH MORE COMFORTABLE SLEEPING CONDITIONS GAINING A
FOOTHOLD OVER THE ENTIRE FORECAST AREA. OVERNIGHT LOWS WILL
GENERALLY BE IN THE 50S...WITH THE RADIATIONAL COOLING PROBABLY
LEADING TO SOME VALLEY FOG ACROSS PARTS OF THE SRN TIER AND FINGER
LAKES REGIONS.
WHILE PLEASANT WEATHER IS EXPECTED ACROSS OUR REGION ON FRIDAY...
A MID LEVEL DISTURBANCE DIGGING INTO THE GREAT LAKES LONGWAVE
TROUGH WILL ENCOURAGE SOME `BAGGINESS` IN THE SFC PRESSURE FIELD
ACROSS THE UPPER OHIO VALLEY. THIS WILL BE THE BEGINNINGS OF WHAT
COULD POTENTIALLY BE A CLOSED LOW FOR OUR REGION DURING THE
UPCOMING WEEKEND. MORE ON THIS LOW CONFIDENCE EVENT IN THE LONG
TERM SECTION BELOW. GENERALLY PARTLY SUNNY SKIES CAN BE EXPECTED
ON FRIDAY WITH AFTERNOON TEMPERATURES IN THE 70S BEING ACCOMPANIED
BY COMFORTABLY LOW HUMIDITY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
ONCE AGAIN...THE MEDIUM RANGE GUIDANCE PACKAGES ARE VASTLY
DIFFERENT IN THEIR SOLUTIONS OVER THE LOWER GREAT LAKES IN THE
DAYS 5-7 PERIOD. BOTH THE GFS AND ECMWF OPERATIONAL MODELS ARE
STUBBORNLY HOLDING ONTO THE SAME SCENARIOS THAT THEY HAVE BEEN
PREACHING FOR THE PAST COUPLE DAYS... WITH THE LATTER DEPICTING
THE DEVELOPMENT OF A STACKED STORM SYSTEM OVER SOUTHERN ONTARIO
AND THE LOWER GREAT LAKES. NEEDLESS TO SAY...THIS WOULD BE A VERY
UNSETTLED SOLUTION FOR OUR FORECAST AREA WITH FAIRLY WIDESPREAD
FREQUENT SHOWERS.
BECAUSE OF THE DISPARITY WITHIN THE GUIDANCE PACKAGES...HAVE NO
CHOICE BUT TO KEEP THE LOW/SLGT CHC BROADBRUSH POPS THAT ARE IN
CONTINUITY IN PLACE THROUGH AT LEAST THE WEEKEND.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
A WEAK COLD FRONT WILL BRIEFLY STALL OUT ALONG OR SLIGHTLY NORTH
OF OUR NORTHERN PERIPHERY THIS MORNING...BEFORE LIFTING BACK NORTH
THIS AFTERNOON AS A WARM FRONT IN RESPONSE TO THE DEVELOPMENT OF
BROAD LOW PRESSURE OVER THE UPPER GREAT LAKES. THERE WILL BE A
CONTINUED RISK OF SCATTERED SHOWERS/THUNDERSTORMS AND ATTENDANT
BRIEF LOCALIZED RESTRICTIONS ALONG AND NEAR THIS BOUNDARY THROUGH
THE DAY...AND ALSO ALONG AND INLAND FROM A DEVELOPING LAKE ERIE
LAKE BREEZE BOUNDARY DURING THE AFTERNOON. OUTSIDE OF ANY SUCH
CONVECTION AND ANY EARLY MORNING SOUTHERN TIER VALLEY FOG...VFR
CONDITIONS SHOULD OTHERWISE PREVAIL.
TONIGHT...THE FRONTAL BOUNDARY WILL FINISH LIFTING OFF TO OUR
NORTH EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND
THE LOSS OF DAYTIME HEATING...ANY LINGERING CONVECTION/ATTENDANT
RESTRICTIONS ACROSS THE FINGER LAKES AND NORTH COUNTRY WILL COME
TO AN END THIS EVENING...LEAVING BEHIND LARGELY DRY/VFR CONDITIONS
FOR THE BALANCE OF THE NIGHTTIME HOURS.
OUTLOOK...
WEDNESDAY...MAINLY VFR INITIALLY...THEN SHOWERS AND THUNDERSTORMS
WITH ATTENDANT REDUCTIONS TO IFR/MVFR BECOMING LIKELY FOR WEDNESDAY
AFTERNOON AND EVENING.
THURSDAY...SCATTERED TO NUMEROUS SHOWERS TAPERING OFF WITH CONDITIONS
IMPROVING TO VFR.
FRIDAY...MAINLY VFR...EXCEPT IN POSSIBLE MORNING SOUTHERN TIER
VALLEY FOG.
SATURDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC COASTLINE WILL SLOWLY
DRIFT OFFSHORE THROUGH MIDWEEK. A STALLED OUT COLD FRONT DRAPED FROM
THE SAINT LAWRENCE VALLEY SOUTHWESTWARD ACROSS LAKE ONTARIO WILL LIFT
BACK NORTH OF THE REGION AS A WARM FRONT THIS AFTERNOON AND EVENING
IN RESPONSE TO DEVELOPING LOW PRESSURE ACROSS THE UPPER GREAT LAKES...
THEN THIS LATTER FEATURE WILL SLOWLY EASE ITS TRAILING COLD FRONT
ACROSS THE AREA WEDNESDAY AFTERNOON AND NIGHT.
THE INITIAL FRONTAL BOUNDARY WILL CONTINUE TO TRIGGER SCATTERED
SHOWERS AND THUNDERSTORMS AS IT LINGERS NEAR THE LOWER GREAT LAKES
THIS MORNING...WITH THESE THEN GRADUALLY DIMINISHING FROM SOUTHWEST
TO NORTHEAST THIS AFTERNOON AND EVENING AS THE BOUNDARY LIFTS AWAY
FROM OUR REGION. FOLLOWING ITS DEPARTURE...GENERALLY DRY CONDITIONS
ARE EXPECTED FOR THE BALANCE OF TONIGHT...BEFORE THE TRAILING COLD
FRONT BRINGS MORE NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES
THROUGH THE REGION WEDNESDAY AFTERNOON AND NIGHT.
WHILE ANY OF THE SHOWERS/STORMS COULD PRODUCE LOCALLY HIGHER WINDS AND
WAVES OVER THE NEXT COUPLE OF DAYS...IN GENERAL LIGHT TO MODEST WINDS
WILL PREVAIL ACROSS THE LOWER LAKES REGION THROUGH WEDNESDAY NIGHT...
ALONG WITH WAVES OF UNDER 3 FEET.
FOLLOWING THE PASSAGE OF THE FRONT...HIGH PRESSURE IS EXPECTED TO
BUILD ACROSS THE REGION THURSDAY AND FRIDAY WHILE BRINGING A RETURN
TO MORE SETTLED CONDITIONS...ALONG WITH CONTINUED LIGHT TO MODEST
WINDS AND MINIMAL WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...JJR
MARINE...JJR
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
950 PM EDT WED SEP 9 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE OFFSHORE THROUGH FRIDAY AS WEAK LOW
PRESSURE DEVELOPS TO THE WEST. LOW PRESSURE WILL PASS NORTH OF THE
REGION SUNDAY PUSHING A COLD FRONT THROUGH THE AREA SUNDAY NIGHT.
HIGH PRESSURE WILL BUILD IN FROM THE WEST EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 950 PM WEDNESDAY...A FEW SHOWERS HAVE REDEVELOPED WEST AND
NORTH OF THE RALEIGH AREA AND THE NEWER RUNS OF THE 3KM HRRR MODEL
NOW SHOW A BETTER COVERAGE OF SCATTERED SHOWERS MOVING INTO OUR
SOUTHERN COUNTIES OVERNIGHT. AS A RESULT...HAVE OPTED TO PUT LOW
POPS BACK INTO THE FORECAST WITH CHC COASTAL PLAINS AND SLIGHT
CHANCE TO THE EAST. ANOTHER WARM MUGGY NIGHT UPCOMING WITH LOWS IN
THE LOW/MID 70S AREA-WIDE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
AS OF 340 PM WED...A DEEP LAYER SOUTHWESTERLY FLOW WILL DEVELOP
AHEAD OF UPPER TROF MOVING ACROSS THE APPALACHIANS. GOOD/HIGH
CHANCE POPS WILL BE FORECAST AS MOISTURE CONVERGENCE INCREASES
OVER EASTERN NC BY AFTERNOON. BULK OF UPPER LEVEL SUPPORT WILL
REMAIN NORTH OF THE REGION SO SEVERE THREAT WILL BE MINIMAL BUT A
CONTINUED THREAT FOR HEAVY DOWNPOURS GIVEN VERY HIGH PRECIPITABLE
WATER. CONDITIONS WILL CONTINUE TO BE VERY MUGGY AND ABOVE CLIMO
WITH HIGHS AROUND 90 INLAND/MID TO UPPER 80S COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
AS OF 315 PM WED...BETTER CHANCE OF PRECIP LATE WEEK AND THIS
WEEKEND, FOLLOWED BY A STRONG FRONTAL PASSAGE AND COOLER/DRIER
CONDITIONS BY EARLY NEXT WEEK.
THURSDAY NIGHT THROUGH FRIDAY...UPPER TROUGH WILL GRADUALLY DEEPEN
AND APPROACH FROM THE WEST...AS SFC LOW ALONG A WEAK FRONTAL
BOUNDARY TO THE NORTH STRENGTHENS AND LIFTS OFF THE MID-ATLANTIC
COAST. MAINTAINED HIGH CHANCE POPS THURSDAY NIGHT THROUGH FRIDAY
FOR INLAND ZONES WITH DEEP SW FLOW...PWAT VALUES NEAR 2 INCHES
AND SHORTWAVE ENERGY ROTATING AROUND STRONGER SHORTWAVE TO THE
NORTHWEST. MUGGY CONDITIONS WILL CONTINUE WITH HIGHS IN THE
MID/UPPER 80S...A FEW DEGREES ABOVE CLIMO.
THIS WEEKEND...A STRONG FRONTAL SYSTEM WILL IMPACT THE REGION
THIS WEEKEND WITH MODELS IN FAIRLY GOOD AGREEMENT. ENC WILL
REMAIN IN THE WARM SECTOR WITH GOOD CHANCES OF WIDESPREAD SHOWERS
AND STORMS SATURDAY AS STRONG UPPER TROUGH DEEPENS TO THE WEST.
MODELS CONTINUE TO SHOW A STRONG SHORTWAVE MOVING THROUGH DURING
PEAK HEATING SAT AFTERNOON. THOUGH CLOUDS/PRECIP MAY INHIBIT
MAXIMUM INSOLATION THEREBY LIMITING INSTABILITY SOMEWHAT.
CONTINUED LIKELY POPS FOR INLAND SECTIONS SATURDAY, TRANSLATING TO
LIKELIES ALONG THE COAST SATURDAY NIGHT AS BEST CONVERGENCE AND
MOISTURE SHIFTS OFFSHORE. INCREASING MID AND UPPER SW FLOW, ALONG
WITH SHORTWAVE IN MEAN SW FLOW COULD BRING A THREAT FOR SEVERE
THUNDERSTORMS AS DEEP LAYER SHEAR INCREASES. THE LIMITING FACTOR
FOR SEVERE THREAT WILL BE AMOUNT OF INSTABILITY. MODELS CONTINUE
TO DIFFER FOR SUNDAY...WITH THE GFS MUCH QUICKER PUSHING THE COLD
FRONT THROUGH...AND ASSOCIATED UPPER LEVEL LOW THROUGH THE MID-
ATLANTIC AND NE STATES. WHILE THE ECMWF IS SLOWER NOT MOVING THE
FRONT THROUGH UNTIL LATE SUN/SUN NIGHT. CONTINUED TO LOWER POPS
SUN NIGHT AND MON.
MONDAY THROUGH WEDNESDAY...SURFACE HIGH PRESSURE WILL BUILD OVER
THE AREA...RESULTING IN COOLER AND MUCH DRIER CONDITIONS. LOW
LEVEL THICKNESS VALUES SUPPORT HIGHS IN THE UPPER 70S/LOW 80S AND
LOWS IN THE UPPER 50S/LOW 60S INLAND AND MID 60S/70 DEGREES ALONG
THE COAST. DEWPOINTS WILL DROP INTO THE 50S BRINGING THE FIRST
EARLY SIGNS OF FALL TO THE REGION UNDER MOSTLY SUNNY SKIES.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
SHORT TERM /THROUGH 00Z FRIDAY/...
AS OF 705 PM WEDNESDAY...PRECIPITATION HAS ENDED ACROSS THE CWA
THIS EVENING AND SOME CLEARING TAKING PLACE FROM SOUTH TO NORTH.
MOST OF THE NUMERICAL GUIDANCE FAVORING MORE OF A STRATUS VERSUS
FOG REGIME TONIGHT. DECENT CONFIDENCE IN AT LEAST MVFR CEILINGS
AND VSBYS FOR A FEW HOURS TOWARD MORNING...BEFORE VFR CONDITIONS
RETURN THROUGH MIDDAY THURSDAY.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 315 PM WED..PERIODS OF SUB-VFR WILL BE POSSIBLE THU
NIGHT THROUGH THE WEEKEND...WITH BETTER CHANCES FOR WIDESPREAD
SHOWERS/TSTMS FRI AND SAT AHEAD OF A STRONG COLD FRONT. PRED VFR
CONDITIONS SHOULD RETURN BY LATE SUNDAY AS COLD FRONT PUSHES
THROUGH THE TERMINALS.
&&
.MARINE...
SHORT TERM /THROUGH THURSDAY/...
AS OF 950 PM WEDNESDAY...LATEST HIGH-RESOLUTION MODELS AND SURFACE
OBSERVATIONS SHOWING A BIT OF AN INCREASE IN WINDS OVER THE
PAMLICO SOUND AND HAVE UPPED THAT AREA TO 15 TO 20 KNOTS
OVERNIGHT. MOST OTHER AREAS SHOULD BE IN THE 10-15 KNOT RANGE AS
SOUTHERLY WINDS CONTINUE. SEAS SHOULD REMAIN IN THE 2-3 FOOT
RANGE OVERNIGHT PER LATEST NWPS. WITH AN INCREASED GRADIENT ON
THURSDAY...WINDS INCREASE TO 10-20 KT THURSDAY AFTERNOON WITH THE
HIGHEST VALUES ON THE OUTER PORTIONS OF THE COASTAL WATERS. SEAS
WILL BUILD TO 3-5 FT THURSDAY AFTERNOON.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 315 PM WED...BRIEF WINDOW OF MARGINAL SCA CONDITIONS
POSSIBLE FOR THE CENTRAL WATERS THU NIGHT AS GRADIENT TIGHTENS
WITH SFC LOW STRENGTHENING TO THE NORTH. WILL CONTINUE TO CAP AT
5FT FOR NOW. VARIABLE WINDS...THOUGH PRED SW 10-15KT CONTINUE FRI
WITH SEAS 2-4FT. PRESSURE GRADIENT INCREASES AGAIN SATURDAY AS
COLD FRONT APPROACHES FROM THE WEST. SW WINDS INCREASING TO
15-25KT WITH SEAS BUILDING TO 4-6FT THEN LINGERING INTO SUNDAY.
PERIOD OF SCA CONDITIONS LIKELY TO DEVELOP...MAINLY SOUTH OF
OREGON INLET. STILL SOME UNCERTAINTY ON WHEN COLD FRONT WILL PUSH
THROUGH THE WATERS...WITH THE GFS FASTER THAN THE ECMWF...BUT WILL
CONTINUE TO SHOW FRONTAL PASSAGE SUN NIGHT INTO EARLY MON MORNING.
CONDITIONS WILL BE IMPROVING QUICKLY MON AS SFC HIGH BUILDS IN
FROM THE WEST.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BTC
NEAR TERM...CTC
SHORT TERM...BTC
LONG TERM...CQD/DAG
AVIATION...CTC/CQD
MARINE...CTC/CQD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
940 PM EDT WED SEP 9 2015
.SYNOPSIS...A SURFACE TROUGH WILL REMAIN OVER CENTRAL NORTH CAROLINA
THROUGH TONIGHT. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
THURSDAY AFTERNOON...BEFORE STALLING ACROSS THE AREA FRIDAY. A
STRONGER COLD FRONT AND UPPER LEVEL LOW WILL APPROACH FROM THE
NORTHWEST FRIDAY NIGHT AND SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 940 PM WEDNESDAY...
A WEAK PERTURBATION EVIDENT AT 700-500 MB IS NOW TRACKING ENE
THROUGH THE WRN CWA... BRINGING SCATTERED SHOWERS AND ISOLATED
BRIEFLY STRONG (BUT SUB-SEVERE) STORMS. THIS CONVECTION IS ALSO
BEING SUPPORTED BY WEAK LINGERING POST-SUNSET ELEVATED INSTABILITY.
DEEP MOIST FLOW PERSISTS WITH GULF AND ATLANTIC SOURCES...
CONTRIBUTING TO PW VALUES WELL ABOVE NORMAL... AROUND 2.0 INCHES.
THE LATEST HRRR AND HI-RES NMM CONTINUE TO TRACK THIS WAVE AND
ASSOCIATED CONVECTION NORTHEAST THROUGH THE CWA THROUGH ABOUT 08Z...
AND THE FORECAST UPDATE WILL REFLECT THIS TIMING AND PLACEMENT...
WITH CHANCE POPS (HIGHEST IN THE CENTRAL AND NE CWA... ALONG THE
SURFACE TROUGH) INTO THE EARLY OVERNIGHT HOURS BEFORE TAPERING
DOWNWARD AND DEPARTING. A SECOND WAVE NOW PUSHING THROUGH SE TN AND
INTO NW GA IS ALSO ON TRACK TO MOVE INTO THE WRN CWA LATE TONIGHT...
AND WHILE IT`S UNCLEAR IF THERE WILL BE ENOUGH ELEVATED INSTABILITY
TO SUSTAIN THIS ACTIVITY WITHIN A MARGINAL DEEP-LAYER SHEAR
ENVIRONMENT... WILL NEED TO LEAVE IN A MENTION OF AT LEAST ISOLATED
STORMS THROUGH THE NIGHT. OTHERWISE... EXPECT MOSTLY CLOUDY SKIES
WITH PLENTY OF CONVECTIVE DEBRIS CLOUDS AS WELL AS PATCHY STRATUS
LATE. LOWS OF 70-75. -GIH
ON THURSDAY...FOG/STRATUS WILL BURN OFF QUICKLY AFTER 10 AM AS
DAYTIME HEATING INCREASES...AND EXPECT LOW CLOUDS TO BECOME
SCATTERED BY LATE MORNING. HOWEVER...RAIN CHANCES WILL INCREASE
DURING EARLY AFTERNOON AS COLD FRONT APPROACHES FROM THE NORTHWEST.
BELIEVE THE MAIN CONCERN WILL BE LOCALLY HEAVY RAINFALL DUE TO DEEP
MOISTURE POOLING AHEAD OF THE FRONT...PUSHING PRECIPITABLE WATER
VALUES IN THE 1.8 TO 2 INCH RANGE FOR MUCH OF THE AREA.
OTHERWISE...LIGHT UPPER LEVEL WINDS AND ONLY MODEST INSTABILITY
SHOULD SUPPORT SCATTERED STORMS...MOST OF WHICH WILL REMAIN BELOW
SEVERE CRITERIA. AFTERNOON HIGH TEMPERATURES WILL RANGE FROM THE
MID/UPPER 80S NORTH TO THE LOW 90S SOUTH.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 330 PM WEDNESDAY...
SOMEWHAT UNSETTLED PATTERN INTO FRIDAY WITH WEAK SURFACE BOUNDARY
OVER EASTERN NORTH CAROLINA WITH WEAK UPPER LEVEL WAVE TRACKING
FROM THE WEST THURSDAY NIGHT INTO FRIDAY MORNING. MODEL
DISCREPANCIES IN TIMING AND STRENGTH OF THIS WAVE EXIST. WHILE
THERE WILL BE SOME TENDENCY FOR DECREASE IN SHWR/TSTM ACTIVITY
THURS NIGHT INTO FRIDAY WITH SURFACE BOUNDARY SHIFTING EAST...IT
REMAINS IN THE AREA AND WASHES OUT TO SOME DEGREE LATE FRIDAY AS
DEEPER UPPER TROUGH DIGS TO THE WEST. UPPER WAVE MAY HELP KEEP
SOME ACTIVITY GOING OVERNIGHT AND 12Z NAM WITH SLOWER TIMING WANTS
TO DEVELOP QUITE A BIT OF PRECIP DURING THE DAY FRIDAY ACROSS
SOUTHERN HALF OF FCST AREA WITH CIRCULATION EVIDENT AT THE
SURFACE. THINK THIS IS OVERDONE AND LEANING TOWARD FASTER AND
DRIER SOLUTIONS FROM 12Z GFS AND ECMWF. BEST CHANCES FOR LINGERING
PRECIP THURS NIGHT AND SOME CONVECTIVE DEVELOPMENT LATER FRIDAY
WILL BE ACROSS SOUTHERN AND EASTERN AREAS...CLOSER TO DECAYING
SURFACE BOUNDARY...BUT NOT GOING HIGHER THAN LOW CHC POPS AT THIS
TIME.
SOME TYPICAL NOCTURNAL DECREASE IN SHOWER ACTIVITY AGAIN ON FRIDAY
NIGHT BUT A FEW MODELS...MOST NOTABLY CANADIAN STILL INDICATE AN
UPPER WAVE AHEAD OF DIGGING TROUGH AND KEEPING SOMETHING GOING...SO
WILL NOT ELIMINATE POPS FRI NIGHT EITHER. THEN BEST CHANCES FOR
MORE WIDESPREAD SHWR/TSTM ACTIVITY WILL BE SATURDAY WITH DIGGING
TROUGH MOVING INTO WESTERN APPALACHIANS AND APPROACHING LOW-LEVEL
BAROCLINIC ZONE WITH INCREASING SW FLOW. LOOKS LIKE THIS NEW FRONTAL
BOUNDARY WILL BE PUSHING THROUGH CENTRAL NC LATE IN THE DAY SATURDAY
AND TIMED FAIRLY WELL WITH MAX HEATING...AND GIVEN SOME UPPER LEVEL
SUPPORT AND AT LEAST MARGINAL SHEAR...STILL LOOKS LIKE A CHANCE FOR
SOME STRONG TO SEVERE STORMS FOR LATE SATURDAY. LIMITED INSTABILITY
WITH LOTS OF CLOUD COVER MAY KEEP A MORE WIDESPREAD SEVERE EVENT
FROM OCCURRING...BUT WORTH KEEPING A CLOSE EYE ON.
HAVE HIGH CHC TO LOW LIKELY POPS SATURDAY...AND NOT GOING HIGHER
ONLY BECAUSE TIMING COULD SHIFT SLOWER INTO THE EVENING SINCE
DIGGING TROUGHS ARE SOMETIMES NOT HANDLED WELL BY MODELS. TRENDS
THOUGH HAVE ACTUALLY BEEN TO SPEED THIS UP A BIT AND FOR NOW HAVE
POPS QUICKLY LOWERING FOR SATURDAY EVENING. THIS MAY ALL NEED TO BE
ADJUSTED.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 PM WEDNESDAY...
DEEP UPPER TROUGH STILL APPEARS TO BE PROGRESSIVE ENOUGH SUCH
THAT SURFACE FRONT LIKELY TO BE EAST OF RAH FCST AREA BY SUNDAY
MORNING...ALONG WITH DEEPER CONVECTION AND HIGHER CHANCES FOR
PRECIP. 12Z GFS ESPECIALLY FAST WITH THIS. HOWEVER AS THE UPPER
TROUGH LIFTS NORTHEAST...COOLER TEMPS ALOFT WILL RESULT IN MID
LEVEL LAPSE RATES THAT COULD SUPPORT VERY SHALLOW CONVECTIVE
SHOWERS... VERY UNLIKELY TO BE ANY THUNDER...MAINLY FOR THE
NORTHERN AND EASTERN PORTIONS OF THE AREA. IF MORE PROGRESSIVE
TRENDS CONTINUE MAY EVENTUALLY DROP PRECIP CHANCES ALTOGETHER FOR
SUNDAY. MAIN STORY SUNDAY WILL BE MUCH COOLER AIR MASS AND WITH AN
ABUNDANCE OF CLOUDS HIGH TEMPS SHOULD BE AT LEAST 5F BELOW NORMAL.
70S FOR MOST LOCATIONS.
FOR THE EARLY PART OF NEXT WEEK THE UPPER TROUGH LIFTS WELL
NORTHEAST OVER NEW ENGLAND AND IS REPLACED BY A SHALLOW UPPER RIDGE
WITH AN ASSOCIATED LARGE AREA OF SURFACE HIGH PRESSURE. THIS WILL
KEEP DEEPER MOISTURE WELL TO THE SOUTH OF THE AREA WITH LOWER
HUMIDITIES AND COOL OVERNIGHTS BUT SLOWLY RECOVERING MAX TEMPS BACK
INTO THE LOWER 80S BY MID WEEK.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 835 PM WEDNESDAY...
24 HOUR TAF PERIOD: AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE
REGION TONIGHT. THIS WILL CONTINUE THE THREAT FOR SCATTERED SHOWERS
AND STORMS... MAINLY AT KRDU/KFAY/KRWI. FOR NOW WILL JUST COVER THE
THREAT WITH TEMPO GROUPS FOR SHOWERS...SUB-VFR CONDITIONS AND GUSTY
WINDS. OTHERWISE... WE MAY SEE SOME LOW STRATUS DEVELOP LATE
TONIGHT/NEAR DAYBREAK (HIGHEST PROBABILITIES ACROSS THE EASTERN TAF
SITES)... WITH ANY SUB-VFR CONDITIONS GENERALLY LIFTING BY MID TO
LATE THURSDAY MORNING.
A WEAK FRONT OR TROUGH WILL APPROACH THURSDAY... HELPING TO
INCREASE CHANCES FOR SHOWERS AND STORMS FOR THURSDAY AFTERNOON AND
EVENING. THUS... HAVE ADDED A PROB30 GROUP FOR THIS TIME FRAME. ANY
SHOWERS AND STORMS THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCED
GUSTY WINDS... SUB VFR CONDITION... HEAVY RAIN AND DANGEROUS CLOUD
TO GROUND LIGHTNING.
LONG TERM: SHOWERS AND THUNDERSTORMS...AS WELL AS SCATTERED MVFR/
IFR CONDITIONS...WILL REMAIN IN THE FORECAST INTO THE WEEKEND AS
THE COLD FRONT STALL ACROSS THE FORECAST AREA THURSDAY EVENING. A
STRONGER COLD FRONT WILL MOVE ACROSS THE AREA SATURDAY NIGHT...WITH
HIGH PRESSURE RETURNING DRIER AIR AND IMPROVED FLYING CONDITIONS FOR
NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/RNK
SHORT TERM...RNK
LONG TERM...RNK
AVIATION...RAH/RNK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
728 PM EDT WED SEP 9 2015
.SYNOPSIS...
CLOUDS AND RAIN CHANCES REMAIN THROUGH LATE IN THE WEEK WITH THE
SLOW APPROACH OF A COLD FRONT. THIS FRONT MAY STALL IN THE AREA
UNTIL EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM WEDNESDAY...ISOLATED SHOWERS AND THUNDERSTORMS CONTINUE
GENERALLY IN THE REGION THE HRRR HAD INDICATED BUT NOT THE COVERAGE
IT WAS ADVERTISING. THE CONVECTION IS GENERALLY EAST OF A LINE FROM
LUMBERTON TO MYRTLE BEACH TO GEORGETOWN.
OVERNIGHT IT IS VERY HARD TO DETECT A SIGNIFICANT SHORTWAVE AS WE
HAD LAST NIGHT. THE MODELS ARE SHOWING THE SURFACE LOW PRESSURE AREA
DEPICTED BY THE MODELS WEAKENING AS IT DRIFTS NORTHWARD. THUS WILL
PROVIDE LITTLE FORCING SO HAVE KEPT ONLY ISOLATED CONVECTION FOR THE
OVERNIGHT PERIOD. FOR LOW TEMPERATURES ARE EXPECTED TO FALL INTO THE
LOWER TO MIDDLE 70S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...A WARM AND MOIST AIRMASS WILL REMAIN IN
PLACE OVER THE EASTERN CAROLINAS IN ADVANCE OF A SLOW-MOVING COLD
FRONT...WHICH WILL BE POSITIONED TO THE NW OVER THE APPALACHIANS
BY THE END OF THE SHORT TERM. THIS FRONT WILL BE PRECEDED BY A
PRE-FRONTAL TROUGH...WHILE AT THE MID LEVELS AN H/5 TROUGH DEEPENS
OVER EASTERN CONUS. AMPLE MOISTURE AND A SERIES OF UPPER
DISTURBANCES ROUNDING THE BASE OF THE H/5 TROUGH MEANS CHANCE POPS
WILL REMAIN IN PLAY FOR BOTH THURSDAY AND FRIDAY. BEST CHANCES FOR
CONVECTION WILL ACTUALLY BE ON FRIDAY...WHEN GUIDANCE SUGGESTS WE
WILL HAVE THE DEEPEST MOISTURE AND WHEN THE PREFRONTAL TROUGH
IMPINGES UPON THE CWA.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 3 PM WEDNESDAY...LOOKS LIKE UNSETTLED WEATHER WILL EXIST
THROUGH MUCH OF THE WEEKEND AS LINGERING FRONT/LOW PRESSURE TROUGH
REMAINS OVER INLAND CAROLINAS THROUGH SATURDAY INTO EARLY SUNDAY.
WINDS WILL BASICALLY STAY SW THROUGH THE COLUMN SAT THROUGH SUNDAY
MORNING WITH DEEP LAYER MOISTURE AND MINOR PERTURBATIONS RIDING
AROUND THE DEEP LONG WAVE MID TO UPPER LEVEL DIGGING DOWN FROM THE
GREAT LAKES TO THE GULF COAST. MAY SEE A DRY PUNCH THROUGH SATURDAY
WITH A DROP IN PCP WATER VALUES DOWN TO LESS THAN 1.5
INCHES...MAINLY INLAND EARLIER IN THE DAY. PCP WATER VALUES UP NEAR
2 INCHES ALONG THE CAPE FEAR COAST WILL SEE SOME DRYING OUT BUT
OVERALL EXPECT A MOIST AND UNSTABLE AIR MASS WITH INCREASED
POTENTIAL FOR SHWRS AND TSTMS THROUGH SATURDAY INTO EARLY SUNDAY
BEFORE NEXT COLD FRONT MOVES IN. ECMWF REMAINS SLIGHTLY DRIER AS
POSITION OF UPPER TROUGH FARTHER EAST THROUGH SATURDAY BUT WILL HAVE
TO SEE WHAT NEW MODEL RUN BRINGS.
THIS MID TO UPPER TROUGH WILL PUSH A COLD FRONT EAST THROUGH THE
CAROLINAS ON SUNDAY WITH PLENTY OF DRY AIR BEHIND IT. THIS RUSH OF
DRY AND RELATIVELY COOLER AIR SHOULD MAKE ITS WAY IN THROUGH SUN
AFTN AS PCP WATER VALUES DROP TO LESS THAN AN INCH WITH AN
ADDITIONAL DROP DOWN TO LESS THAN A HALF INCH BY MON INTO TUES. 850
TEMPS SHOW A DROP FROM NEAR 17C SAT EVENING TO 11C BY MON MORNING.
THEREFORE EXPECT TEMPS DOWN BELOW NORMAL...CLOSER TO 80 FOR HIGHS
AND DEWPOINT TEMPS DOWN BELOW 50 IN SPOTS INLAND AND MID 50S MOST
PLACES MON INTO TUES. THIS VERY DRY AIR IN PLACE WILL CREATE LARGER
DIURNAL RANGES WITH LOW TEMPS TO DROP INTO THE 50S AND 60S ALONG THE
COAST SUN NIGHT AND MON NIGHT.
OVERALL EXPECT UNSETTLED WEATHER WITH PLENTY OF CLOUDS AND INCREASED
POTENTIAL FOR SHWRS/TSTMS IN A MORE HUMID AIR MASS AHEAD OF COLD
FRONT THROUGH EARLY SUNDAY. THEN MUCH LESS HUMID WEATHER WITH COOLER
NIGHT AND WARMER EVE THROUGH TUES AS DRY HIGH PRESSURE DOMINATES OUR
WEATHER. BY LATE NEXT WED WINDS WILL COME AROUND BECOMING MORE ON
SHORE WITH A SLIGHT INCREASE IN MOISTURE BUT ANY PCP SHOULD HOLD OFF
UNTIL WED NIGHT OR THURS.
&&
.AVIATION /00Z WEDNESDAY THROUGH MONDAY/...
AS OF 00Z...CONVECTION AT AREA TERMINALS APPEARS TO BE DONE FOR THE
NIGHT...THOUGH THERE IS AN OUTSIDE CHANCE INLAND TERMINALS COULD BE
AFFECTED BY A DECAYING CELL AROUND MIDNIGHT. CONFIDENCE IN THIS IS
LOW HOWEVER AND INLAND TAFS ONLY CONTAIN DEBRIS CLOUDS FOR NOW.
LATE TONIGHT MVFR/IFR CIGS ARE POSSIBLE AT ALL TERMINALS WITH WORST
CONDITIONS ANTICIPATED INLAND. THERE SHOULD BE ENOUGH WIND TO
PRECLUDE SIGNIFICANT FOG BUT MVFR VSBYS A POSSIBILITY. AFTER
SUNRISE...CONTINUED HOT AND HUMID WITH MAINLY AFTERNOON CONVECTION
POSSIBLE. SOUTHWEST GRADIENT WILL BE STRONGER THAN TODAY AND COULD
BECOME GUSTY IN THE AFTERNOON.
EXTENDED OUTLOOK...POSSIBLE NUMEROUS STORMS FRIDAY AND SATURDAY.
STORMS ENDING SUNDAY MORNING WITH COOLER CONDITIONS INTO MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM WEDNESDAY...SOUTH TO SOUTH-SOUTHWEST WINDS OF 10 TO 15
KTS WITH SEAS OF 2 TO 3 FEET ARE CURRENTLY OCCURRING OVER THE
COASTAL WATERS. AS HIGH PRESSURE WEAKENS SLOWLY OVERNIGHT AND THE
INFLUENCE OF A COLD FRONT WEST OF THE CAROLINAS WILL CAUSE THE WINDS
TO BECOME MORE SOUTHWESTERLY OVERNIGHT. WINDS SPEEDS ARE FORECAST TO
RUN AROUND 15 KNOT. SEAS WILL RUN AROUND 3 FEET WITH A FEW 4 FOOTS
IN THE SOUTHEAST PORTIONS OF THE LITTLE RIVER TO CAPE FEAR MARINE
ZONE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...WINDS WILL REMAIN SOUTHWESTERLY THROUGH THE
PERIOD AS A COLD FRONT SLOWLY ADVANCES UPON THE WATERS. THE FRONT
WILL NOT MAKE IT TO THE WATERS DURING THE NEAR TERM...BUT WE WILL
LIKELY SEE A GRADUAL TIGHTENING OF THE GRADIENT...WHICH WILL
INCREASE WINDS FROM A GENERAL 10 TO 15 KT RANGE TO AROUND 15 KTS
OR SO BY FRIDAY NIGHT. SEAS WILL LIKEWISE INCREASE...WITH 3 TO 4
FT SEAS DEVELOPING FRIDAY/FRIDAY NIGHT.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 PM WEDNESDAY...DECENT SW FLOW THROUGH MUCH OF THE WEEKEND
AS TROUGH OF LOW PRESSURE REMAINS JUST INLAND OF COAST. DECENT
GRADIENT THROUGH SAT MORNING WITH SW WINDS UP TO 15 KTS WILL
DIMINISH THROUGH LATE SATURDAY INTO SUNDAY AS WINDS BEGIN TO VEER
AROUND AS COLD FRONT APPROACHES FROM THE WEST. LATEST WNA SHOWS WIND
SHIFT TO W-NW BY LATE SUNDAY AS COLD FRONT CROSSES THE WATERS.
PERSISTENT SW WINDS WILL PUSH SEAS UP TO 3 TO 5 FT THROUGH SAT AND
THEN DIMINISHING WITH OFF SHORE FLOW THROUGH LATE SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...REK
NEAR TERM...DRH
SHORT TERM...REK/MBB
LONG TERM...RGZ
AVIATION...RAN
MARINE...REK/RGZ/DRH
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
709 PM EDT WED SEP 9 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE OFFSHORE THROUGH FRIDAY AS WEAK LOW
PRESSURE DEVELOPS TO THE WEST. LOW PRESSURE WILL PASS NORTH OF THE
REGION SUNDAY PUSHING A COLD FRONT THROUGH THE AREA SUNDAY NIGHT.
HIGH PRESSURE WILL BUILD IN FROM THE WEST EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 705 PM WEDNESDAY...PRECIPITATION HAS DISSIPATED OVER ALL
LAND AREAS OF OUR CWA AS MID-LEVEL SHORTWAVE EXITS THE REGION.
WILL DROP POPS COMPLETELY ALONG THE COAST BUT WILL KEEP A SLIGHT
CHANCE INLAND AS LATEST HRRR AND NAM12 DO SHOW SOME REDEVELOPMENT
TOWARD MORNING. ANOTHER WARM MUGGY NIGHT UPCOMING WITH LOWS IN THE
LOW/MID 70S AREA-WIDE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
AS OF 340 PM WED...A DEEP LAYER SOUTHWESTERLY FLOW WILL DEVELOP
AHEAD OF UPPER TROF MOVING ACROSS THE APPALACHIANS. GOOD/HIGH
CHANCE POPS WILL BE FORECAST AS MOISTURE CONVERGENCE INCREASES
OVER EASTERN NC BY AFTERNOON. BULK OF UPPER LEVEL SUPPORT WILL
REMAIN NORTH OF THE REGION SO SEVERE THREAT WILL BE MINIMAL BUT A
CONTINUED THREAT FOR HEAVY DOWNPOURS GIVEN VERY HIGH PRECIPITABLE
WATER. CONDITIONS WILL CONTINUE TO BE VERY MUGGY AND ABOVE CLIMO
WITH HIGHS AROUND 90 INLAND/MID TO UPPER 80S COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
AS OF 315 PM WED...BETTER CHANCE OF PRECIP LATE WEEK AND THIS
WEEKEND, FOLLOWED BY A STRONG FRONTAL PASSAGE AND COOLER/DRIER
CONDITIONS BY EARLY NEXT WEEK.
THURSDAY NIGHT THROUGH FRIDAY...UPPER TROUGH WILL GRADUALLY DEEPEN
AND APPROACH FROM THE WEST...AS SFC LOW ALONG A WEAK FRONTAL
BOUNDARY TO THE NORTH STRENGTHENS AND LIFTS OFF THE MID-ATLANTIC
COAST. MAINTAINED HIGH CHANCE POPS THURSDAY NIGHT THROUGH FRIDAY
FOR INLAND ZONES WITH DEEP SW FLOW...PWAT VALUES NEAR 2 INCHES
AND SHORTWAVE ENERGY ROTATING AROUND STRONGER SHORTWAVE TO THE
NORTHWEST. MUGGY CONDITIONS WILL CONTINUE WITH HIGHS IN THE
MID/UPPER 80S...A FEW DEGREES ABOVE CLIMO.
THIS WEEKEND...A STRONG FRONTAL SYSTEM WILL IMPACT THE REGION
THIS WEEKEND WITH MODELS IN FAIRLY GOOD AGREEMENT. ENC WILL
REMAIN IN THE WARM SECTOR WITH GOOD CHANCES OF WIDESPREAD SHOWERS
AND STORMS SATURDAY AS STRONG UPPER TROUGH DEEPENS TO THE WEST.
MODELS CONTINUE TO SHOW A STRONG SHORTWAVE MOVING THROUGH DURING
PEAK HEATING SAT AFTERNOON. THOUGH CLOUDS/PRECIP MAY INHIBIT
MAXIMUM INSOLATION THEREBY LIMITING INSTABILITY SOMEWHAT.
CONTINUED LIKELY POPS FOR INLAND SECTIONS SATURDAY, TRANSLATING TO
LIKELIES ALONG THE COAST SATURDAY NIGHT AS BEST CONVERGENCE AND
MOISTURE SHIFTS OFFSHORE. INCREASING MID AND UPPER SW FLOW, ALONG
WITH SHORTWAVE IN MEAN SW FLOW COULD BRING A THREAT FOR SEVERE
THUNDERSTORMS AS DEEP LAYER SHEAR INCREASES. THE LIMITING FACTOR
FOR SEVERE THREAT WILL BE AMOUNT OF INSTABILITY. MODELS CONTINUE
TO DIFFER FOR SUNDAY...WITH THE GFS MUCH QUICKER PUSHING THE COLD
FRONT THROUGH...AND ASSOCIATED UPPER LEVEL LOW THROUGH THE MID-
ATLANTIC AND NE STATES. WHILE THE ECMWF IS SLOWER NOT MOVING THE
FRONT THROUGH UNTIL LATE SUN/SUN NIGHT. CONTINUED TO LOWER POPS
SUN NIGHT AND MON.
MONDAY THROUGH WEDNESDAY...SURFACE HIGH PRESSURE WILL BUILD OVER
THE AREA...RESULTING IN COOLER AND MUCH DRIER CONDITIONS. LOW
LEVEL THICKNESS VALUES SUPPORT HIGHS IN THE UPPER 70S/LOW 80S AND
LOWS IN THE UPPER 50S/LOW 60S INLAND AND MID 60S/70 DEGREES ALONG
THE COAST. DEWPOINTS WILL DROP INTO THE 50S BRINGING THE FIRST
EARLY SIGNS OF FALL TO THE REGION UNDER MOSTLY SUNNY SKIES.
&&
.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
SHORT TERM /THROUGH 00Z FRIDAY/...
AS OF 705 PM WEDNESDAY...PRECIPITATION HAS ENDED ACROSS THE CWA
THIS EVENING AND SOME CLEARING TAKING PLACE FROM SOUTH TO NORTH.
MOST OF THE NUMERICAL GUIDANCE FAVORING MORE OF A STRATUS VERSUS
FOG REGIME TONIGHT. DECENT CONFIDENCE IN AT LEAST MVFR CEILINGS
AND VSBYS FOR A FEW HOURS TOWARD MORNING...BEFORE VFR CONDITIONS
RETURN THROUGH MIDDAY THURSDAY.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 315 PM WED..PERIODS OF SUB-VFR WILL BE POSSIBLE THU
NIGHT THROUGH THE WEEKEND...WITH BETTER CHANCES FOR WIDESPREAD
SHOWERS/TSTMS FRI AND SAT AHEAD OF A STRONG COLD FRONT. PRED VFR
CONDITIONS SHOULD RETURN BY LATE SUNDAY AS COLD FRONT PUSHES
THROUGH THE TERMINALS.
&&
.MARINE...
SHORT TERM /THROUGH THURSDAY/...
AS OF 705 PM THURSDAY...MINIMAL CHANGES MADE TO CURRENT
FORECAST...MAINLY TO TWEAK WIND DIRECTIONS TO MORE SOUTHERLY
VERSUS SOUTHWEST. HRRR/RUC INDICATE A BIT OF AN INCREASE IN WINDS
LATE TONIGHT...BUT WILL CAP AT 15 KNOTS FOR NOW. SEAS SHOULD
REMAIN IN THE 2-3 FOOT RANGE OVERNIGHT PER LATEST NWPS. WITH AN
INCREASED GRADIENT ON THURSDAY...WINDS INCREASE TO 10-20 KT
THURSDAY AFTERNOON WITH THE HIGHEST VALUES ON THE OUTER PORTIONS
OF THE COASTAL WATERS. SEAS WILL BUILD TO 3-5 FT THURSDAY
AFTERNOON.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 315 PM WED...BRIEF WINDOW OF MARGINAL SCA CONDITIONS
POSSIBLE FOR THE CENTRAL WATERS THU NIGHT AS GRADIENT TIGHTENS
WITH SFC LOW STRENGTHENING TO THE NORTH. WILL CONTINUE TO CAP AT
5FT FOR NOW. VARIABLE WINDS...THOUGH PRED SW 10-15KT CONTINUE FRI
WITH SEAS 2-4FT. PRESSURE GRADIENT INCREASES AGAIN SATURDAY AS
COLD FRONT APPROACHES FROM THE WEST. SW WINDS INCREASING TO
15-25KT WITH SEAS BUILDING TO 4-6FT THEN LINGERING INTO SUNDAY.
PERIOD OF SCA CONDITIONS LIKELY TO DEVELOP...MAINLY SOUTH OF
OREGON INLET. STILL SOME UNCERTAINTY ON WHEN COLD FRONT WILL PUSH
THROUGH THE WATERS...WITH THE GFS FASTER THAN THE ECMWF...BUT WILL
CONTINUE TO SHOW FRONTAL PASSAGE SUN NIGHT INTO EARLY MON MORNING.
CONDITIONS WILL BE IMPROVING QUICKLY MON AS SFC HIGH BUILDS IN
FROM THE WEST.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BTC
NEAR TERM...CTC
SHORT TERM...BTC
LONG TERM...CQD/DAG
AVIATION...CTC/CQD
MARINE...BTC/CTC/CQD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
817 PM CDT WED SEP 9 2015
.UPDATE...
ISSUED AT 816 PM CDT WED SEP 9 2015
UPDATED THE POPS WITH THE HRRR MODEL WHICH SEEMED TO DEPICT SOME
OF THE RETURNS THE RADAR SHOWS. SO WENT WITH SLIGHT CHANCE OF
SHOWERS SOUTHWEST INTO THE SOUTH CENTRAL THIS EVENING.
UPDATE ISSUED AT 628 PM CDT WED SEP 9 2015
COLD FRONT WITH NO SIGNIFICANT WEATHER HAS MOVED THROUGH THE
STATE. SKIES WILL CLEAR ACROSS THE NORTH TONIGHT WHILE MORE CLOUDS
REMAIN ACROSS THE SOUTH. COOLEST TEMPERATURES OVERNIGHT ARE
FORECAST WHERE CLOUDS WILL BE CLEAR IN THE NORTH. THIS IS WHERE
THE FROST ADVISORY HAS BEEN ISSUED FOR TONIGHT. CURRENT FORECAST
TRENDING WELL WITH NO MAJOR CHANGES.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 305 PM CDT WED SEP 9 2015
FROST TONIGHT NORTH CENTRAL HIGHLIGHTS THE SHORT TERM FORECAST.
ISSUED A FROST ADVISORY FOR NORTH CENTRAL NORTH DAKOTA AND THE
TURTLE MOUNTAINS AREA FOR TONIGHT INTO THURSDAY MORNING AS COOL
SURFACE HIGH PRESSURE BUILDS IN. IT APPEARS THAT THESE
AFOREMENTIONED AREAS WILL REMAIN CLEAR THROUGH THE
NIGHT...REMAINING IN BETWEEN THE WRAP AROUND STRATUS FIELD IN
SOUTHERN CANADA AND THE MID LEVEL DECKS FORECAST TO REMAIN ACROSS
THE WEST AND SOUTH CENTRAL. THUS...DID UNDERCUT THE 12 UTC
GUIDANCE CONSENSUS FOR THESE AREAS WITH FORECAST LOWS IN THE MID
30S...IN LINE WITH WHAT OCCURRED ACROSS CANADA THIS MORNING IN A
SIMILAR SETUP. GIVEN CLOUD COVER...FORECAST LOWS IN THE 40S ARE
EXPECTED ELSEWHERE. HOWEVER...THIS WILL HAVE TO BE MONITORED. A
COOL THURSDAY IS FORECAST WITH HIGH PRESSURE REMAINING OVER THE
AREA WITH HIGHS IN THE 60S FOR ALL OF WESTERN AND CENTRAL NORTH
DAKOTA.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED SEP 9 2015
QUIET AND COOL INTO THE BEGINNING OF NEXT WEEK...THEN CHANCES OF
SHOWERS AND THUNDERSTORMS RETURN TO THE FORECAST.
THURSDAY NIGHT A COOL SURFACE HIGH SETTLES OVER THE EASTERN DAKOTAS
WITH CLEAR TO PARTLY CLOUDY SKIES AND LIGHT WINDS. EXPECT
RADIATIONAL COOLING WITH DEWPOINTS IN THE 30S TO ALLOW TEMPERATURES
TO DIP INTO THE MID 30S. AS A RESULT...PATCHY FROST IS FORECAST OVER
PARTS OF WESTERN AND CENTRAL NORTH DAKOTA LATE THURSDAY NIGHT INTO
EARLY FRIDAY MORNING.
THE WEST COAST RIDGE AMPLIFIES THROUGH THE NORTHERN ROCKIES WITH
MEAN RIDGING THROUGH NORTH DAKOTA BY THE END OF THE DAY FRIDAY. THIS
SPELLS A WARMING TREND THROUGH THE WEEKEND AFTER A COOL MORNING ON
FRIDAY.
BY MONDAY NIGHT THE REGION COMES UNDER SOUTHWEST MID LEVEL FLOW AND
INCREASED MOISTURE AND INSTABILITY...AS A PACIFIC NORTHWEST LONG
WAVE TROUGH DEEPENS AND BY MID WEEK CUTS OFF OVER THE SOUTHERN
CANADIAN PRAIRIE PROVINCES. THE BASE OF THE TROUGH LIFTS NORTHEAST
INTO THE DAKOTAS TUESDAY NIGHT INTO WEDNESDAY. THUS HAVE CHANCES FOR
THUNDERSTORMS MONDAY NIGHT THROUGH TUESDAY NIGHT AHEAD OF THE
SYSTEM...AND RAIN SHOWERS WEDNESDAY BEHIND THE SYSTEM.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 628 PM CDT WED SEP 9 2015
SURFACE HIGH PRESSURE ACROSS SOUTHERN CANADA WILL MOVE SOUTH INTO
THE NORTHERN PLAINS TONIGHT AND THURSDAY. VFR EXPECTED THROUGH THE
00Z TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 4 AM TO 9 AM CDT THURSDAY FOR NDZ002>005-
011>013.
&&
$$
UPDATE...WAA
SHORT TERM...AYD
LONG TERM...JV
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1235 AM CDT TUE SEP 8 2015
.UPDATE...
ISSUED AT 1235 AM CDT TUE SEP 8 2015
HIGH RES MODELS INDICATE THERE WILL BE A CHANCE FOR SOME LIGHT
SHOWERS NORTHWEST INTO NORTH CENTRAL EARLY THIS MORNING AS AN
UPPER LEVEL TROUGH MOVES EAST ACROSS FAR SOUTH CENTRAL CANADA.
ANOTHER SLIGHT CHANCE FOR SHOWERS FAR SOUTHWEST WHERE AN EMBEDDED
WAVE IS DEPICTED TO TRACK NEAR. OVERALL INSIGNIFICANT BUT OPTED TO
ADD/MAINTAIN IN THE FORECAST. TEMPERATURES ONCE AGAIN DROPPING TO
BELOW GUIDANCE...SO TWEAKED BASED ON LATEST OBSERVATIONS.
OPTED TO ALSO THROW IN PATCHY FOG ACROSS MY SOUTHEAST QUARTER
WHERE LAST FEW HRRR RUNS INDICATE SOME DEVELOPMENT. NOT OUT OF THE
QUESTION WITH T/TD SPREADS IN THIS AREA AT OR NEAR ZERO ALREADY.
UPDATE ISSUED AT 918 PM CDT MON SEP 7 2015
ONE STRONG THUNDERSTORM REMAINS OVER FAR SOUTHWEST DICKEY IN THE
APEX OF AN AXIS OF INSTABILITY EXTENDING INTO SOUTH DAKOTA.
LATEST MESO-ANALYSIS INDICATES THE STORM MAY NOW BE MOVING AHEAD
OF THE GREATEST INSTABILITY...ALTHOUGH SHEAR REMAINS ABUNDANT.
HAVE EXTENDED THUNDERSTORM CHANCES THROUGH 04Z ACROSS SOUTHERN
DICKEY COUNTY.
SHOWERS HAVE ALL BUT DISSIPATED ACROSS THE NORTHWEST AND NORTH
CENTRAL. COULD STILL SEE A SPRINKLE OR TWO THIS EVENING BUT NOT
ENOUGH COVERAGE TO KEEP A MENTION OF MEASURABLE PRECIPITATION.
UPDATE ISSUED AT 701 PM CDT MON SEP 7 2015
QUICK UPDATE TO ADD A MENTION OF THUNDER FOR A FEW HOURS THIS
EVENING OVER THE FAR SOUTH CENTRAL FROM AROUND STRASBURG ACROSS
MCINTOSH AND INTO DICKEY COUNTY. AXIS OF INSTABILITY OVER CENTRAL
SOUTH DAKOTA IS EXTENDING INTO THE FAR SOUTH CENTRAL WITH GOOD
BULK SHEAR OVER THE AREA. THIS SHOULD BE A SHORT LIVED EVENT
ENCOMPASSING THIS SMALL AREA.
UPDATE ISSUED AT 632 PM CDT MON SEP 7 2015
AFTERNOON SHOWERS HAVE EXITED EASTERN PORTIONS OF CENTRAL NORTH
DAKOTA. A FEW SHOWERS WERE LOCATED OVER NORTHEAST MONTANA INTO FAR
NORTHWEST NORTH DAKOTA ASSOCIATED WITH A SHORTWAVE ROTATING
AROUND THE BASE OF THE UPPER LEVEL LOW OVER MANITOBA. MOST LIKELY
NOTHING MORE THAN A SPRINKLE OR BRIEF SHOWER EXPECTED HERE BUT DID
KEEP SOME SLIGHT CHANCE POPS OVER THE NORTHWEST EARLY THIS
EVENING. ALSO BUMPED UP SKY COVER A BIT OVER THE NORTHWEST.
OTHERWISE NO SIGNIFICANT UPDATES TO THE GOING FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 256 PM CDT MON SEP 7 2015
RAIN SHOWERS ENDING BY EARLY THIS EVENING CENTRAL HIGHLIGHT THE
SHORT TERM FORECAST.
WILL CONTINUE TO RELY ON A TIME LAGGED ENSEMBLE OF THE HRRR FOR
POPS THE REMAINDER OF THE AFTERNOON...NAMELY ITS 16-18 UTC
ITERATIONS...WHICH HAS DONE WELL THROUGHOUT THE DAY. DID MAINTAIN
A SLIGHT CHANCE OF THUNDER WITH A FEW...SPORADIC LIGHTNING
STRIKES OBSERVED. EXPECT PRECIPITATION CHANCES...FOCUSED PRIMARILY
ACROSS NORTH CENTRAL NORTH DAKOTA AND THE UPPER JAMES RIVER VALLEY
THE REST OF THE DAY...TO RAPIDLY DECREASE BY 22-23 UTC AS FORCING
FROM TWO SHORTWAVES SOUTH OF THE UPPER LOW NEAR LAKE WINNIPEG
SHIFTS EAST.
FOR TUESDAY...A QUIET...DRY...ALBEIT SLIGHTLY BELOW NORMAL
TEMPERATURE-WISE DAY IS FORECAST SOUTH OF THE NOW FILLING
AFOREMENTIONED LOW. GIVEN GOOD AGREEMENT...UTILIZED A BLEND OF THE
12 UTC GUIDANCE SUITES FOR ALL FIELDS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 256 PM CDT MON SEP 7 2015
NORTHWEST FLOW ALOFT THROUGH FRIDAY WITH FLOW ROTATING AROUND THE
HUDSON BAY LOW AND RIDGE OVER THE EASTERN PACIFIC AND WEST COAST.
SHORTWAVE ENERGY MOVING THROUGH THIS FLOW APPROACHES NORTHERN NORTH
DAKOTA LATE TUESDAY NIGHT/WEDNESDAY MORNING...WITH AN ATTENDANT WEAK
SURFACE LOW AND COLD FRONT. MORE SHORTWAVE ENERGY IMPULSES MOVE
SOUTHEAST ACROSS THE STATE WEDNESDAY AFTERNOON WITH A COLD FRONT
MOVING SOUTH ACROSS THE STATE. THIS WILL RESULT IN SLIGHT CHANCES OF
SHOWERS...MAINLY NORTHWEST AND CENTRAL...ON WEDNESDAY. SEASONABLE
TEMPERATURES WEDNESDAY WITH HIGHS FROM THE UPPER 60S NORTH TO UPPER
70S SOUTH.
ANOTHER SERIES OF SHORTWAVES MOVES ACROSS THE STATE WEDNESDAY NIGHT
WITH A SECONDARY PUSH OF COLD AIR IN THE FORM OF A BACKDOOR COLD
FRONT MOVING SOUTHWEST ACROSS THE STATE. SLIGHT CHANCES OF SHOWERS
WILL REMAIN IN THE FORECAST NORTHWEST AND CENTRAL WEDNESDAY
NIGHT...WITH MAINLY DRY BUT COOL CONDITIONS EXPECTED THURSDAY. LOOK
FOR HIGHS IN THE 60S TO LOWER 70S.
THE UPPER LEVEL WESTERN RIDGE BUILDS BACK INTO THE REGION FOR THE
WEEKEND...WITH DRY CONDITIONS AND SLIGHTLY ABOVE AVERAGE
TEMPERATURES. HIGHS IN THE 70S TO LOWER 80S.
THE MODELS BRING AN UPPER LEVEL SHORTWAVE MOVING THROUGH THE
FLOW...FLATTENING THE RIDGE...BRINGING A CHANCE OF SHOWERS AND
COOLER WEATHER FOR MONDAY WITH HIGHS MAINLY IN THE 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1235 AM CDT TUE SEP 8 2015
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD WITH MID TO
UPPER LEVEL CLOUDS STREAMING EAST ACROSS THE REGION. AN ISOLATED
SHOWER POSSIBLE NORTHWEST EARLY THIS MORNING BUT TOO SCARCE TO
MENTION IN KISN OR KMOT TAF. PATCHY FOG MAY BE POSSIBLE AT
KBIS/KJMS TONIGHT. HOWEVER...GIVEN HIGH UNCERTAINTY...LEFT THIS
ALSO OUT OF THE TAFS FOR NOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...AYD
LONG TERM...JV
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
748 PM EDT WED SEP 9 2015
.SYNOPSIS...
A COLD FRONT OVER NORTHERN OHIO WILL CONTINUE TO MOVE SOUTHEAST
AWAY FROM THE LOCAL AREA TONIGHT. THE FRONT IS EXPECTED TO
EVENTUALLY STALL NEAR THE OHIO RIVER ON THURSDAY MORNING. WEAK
HIGH PRESSURE WILL BUILD OVER THE REGION TOMORROW AND TOMORROW
NIGHT. ANOTHER COLD FRONT WILL FOLLOW ON FRIDAY WITH A POTENT
UPPER AIR DISTURBANCE EXPECTED TO IMPACT THE LOCAL AREA OVER THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
SHOWERS HAVE DIMINISHED ACROSS MOST OF THE AREA EXCEPT A FEW
SPRINKLES THAT MOVED INTO SOUTHERN HANCOCK COUNTY. MOST AREAS WILL
BE DRY FOR THE REMAINDER OF THE NIGHT BUT LEFT A LOW 20-30 POP IN
ACROSS THE SOUTHERN COUNTIES AS SOME SHORTWAVE ENERGY CONTINUES TO
STREAM NORTHEAST. LOW LEVEL DRY AIR SHOULD WIN OUT ACROSS THE
NORTHERN COUNTIES AND REMOVED ANY REMAINING CHANCE OF RAIN FROM
THE FORECAST. LOW CLOUDS HAVE ALREADY SCATTERED OUT ACROSS NW OHIO SO
ANY PRECIPITATION REACHING THE GROUND WILL BE VERY LIGHT AS IT
FALLS OUT OF A MID-CLOUD DECK.
PREVIOUS DISCUSSION...
AS FEARED...LITTLE PRECIP HAS DEVELOPED THIS AFTERNOON. SOME
SCATTERED SHOWERS REMAIN OVER THE EASTERN END OF THE AREA. MOST OF
THE GUIDANCE INCLUDING THE LATEST RUC AND HRRR SHOW THE
POSSIBILITY OF NEW DEVELOPMENT THROUGH EARLY EVENING FROM ABOUT
I-71 EAST. THIS SEEM PLAUSIBLE GIVEN THE SHOWERS OVER INDIANA AND
SW OHIO SO WILL KEEP A SMALL MENTION FOR A FEW HOURS. BY MIDNIGHT
ALL BUT THE SE END OF THE AREA SHOULD BE DRY. THE SURFACE FRONT
WILL EVENTUALLY STALL AND THE THREAT FOR SHOWERS ACROSS THE SE TIP
OF THE AREA COULD PERSIST INTO THURSDAY MORNING. THE NEAREST
CLEARING IS STILL BACK BY CHICAGO SO THAT WILL TAKE SOME TO REACH
THE LOCAL AREA AS WELL. DO THINK THAT THAT ABOUT THE NW 1/3 TO
1/2 OF THE AREA WILL BECOME PARTLY CLOUDY BY MORNING. THIS WILL
RESULT IN A DECENT TEMPERATURE GRADIENT ACROSS THE AREA WITH LOW
60S IN THE SE AND READINGS WELL DOWN INTO THE 50S IN THE NW.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
JUST MINOR ADJUSTMENTS TO THE SHORT TERM TODAY AS THE PREVIOUS
PACKAGE WAS ON THE RIGHT TRACK. THURSDAY AND THURSDAY NIGHT WILL
BE DRY. ANOTHER COLD FRONT IS STILL ON TRACK FOR FRIDAY. VERY
LITTLE IF ANY PRECIP IS EXPECTED BEFORE 12Z. WILL END UP GOING
WITH A FEW HOURS OF LIKELY MOST AREAS. UNFORTUNATELY THE BEST
WINDOW FOR PRECIP IN THE EAST WILL BE FRIDAY AFTERNOON AND
EVENING. THERE WILL BE A DISTINCT AIRMASS CHANGE BEHIND THIS FRONT
WITH THE UNSEASONABLY COOL AIR SETTLING OVER THE AREA OVER THE
WEEKEND. AS A RESULT...INSTABILITY SHOWERS HELPED ALONG BY LAKE
ERIE CAN BE EXPECTED BOTH SATURDAY AND SUNDAY. BY 12Z SUNDAY 500
MB TEMPS WILL BE ON THEIR WAY TO NEG 20 OR COLDER WHICH WILL GIVE
LAKE TO 500MB TEMP DIFFERENCES OF 45 DEGREES OR GREATER. THIS
MEANS THUNDER WILL BE A GOOD BET DOWNWIND OF THE LAKE AND HAVE
BUMPED PRECIP CHANCES TO LIKELY IN FAR NE OH AND NW PA FOR
SATURDAY NIGHT. HAVE CONTINUED THE RECENT TREND OF LOWERING HIGH
TEMPS OVER THE WEEKEND. THERE COULD BE A FEW AREAS THAT FAIL TO
GET OUT OF THE 50S FOR HIGHS ON SUNDAY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AN UPPER LEVEL LOW WILL BE MOVING OFF TO THE EAST ON SUNDAY WILL
BRING COLDER TEMPERATURES 10-15 DEGREES BELOW AVERAGE AND
NORTHWESTERLY FLOW TO NORTHERN OHIO AND NORTHEAST PA. THIS NORTHWEST
FLOW OFF OF LAKE ERIE...PLUS 850 MB TEMPERATURES OF 6-8C...AND WARM
LAKE WATER TEMPERATURES AROUND 70F (A TEMPERATURE DIFFERENCE OF
AROUND 25 DEGREES FAHRENHEIT) WILL ALLOW FOR SOME SIGNIFICANT
LAKE EFFECT RAIN TO DEVELOP OVER THE AREA ON SUNDAY INTO THE EARLY
PART OF MONDAY. IN SHORT...SUNDAY WILL BE MORE REPRESENTATIVE OF A
COLD AND RAINY NOVEMBER DAY THAN THE GLIMPSE OF JULY THAT WE HAD
OVER LABOR DAY WEEKEND.
LATE ON MONDAY...SOME UPPER LEVEL RIDGING WILL MOVE IN ALONG WITH A
SURFACE HIGH PRESSURE. WINDS WILL SHIFT TO COME FROM THE SOUTH AND
WILL WARM TEMPERATURES CLOSER TO CLIMO AND DRY THE AREA OUT FROM WET
WEATHER OVER THE WEEKEND. HIGH PRESSURE LOOKS TO BE IN PLACE THROUGH
A MAJORITY OF WEDNESDAY ALLOWING FOR A COUPLE OF DRY...TYPICAL MID-
SEPTEMBER DAYS IN NORTHERN OHIO AND NORTHWEST PA.
MODELS CURRENTLY DEPICT A COLD FRONT BEGINNING TO APPROACH THE AREA
BY THURSDAY MORNING...WHICH COULD BRING SOME WET WEATHER FOR THE END
OF NEXT WEEK. STILL A LITTLE FAR OUT TO TELL WHAT COULD HAPPEN WITH
THIS SYSTEM AS IT APPROACHES THE EASTERN GREAT LAKES.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
THE COLD FRONT IS OVER CENTRAL OHIO AND DRIFTING SOUTH. A WEAK
WAVE OF LOW PRESSURE WILL RIDE ALONG THE FRONT OVERNIGHT BUT
SHOULD HAVE MINIMAL IMPACT ON THE PRACTICAL WEATHER I THE FORECAST
AREA. A FEW PATCHES OF MVFR CLOUDS MAY OCCUR AT KCLE KMFD KCAK
AND KYNG. CANNOT RULE OUT A SPRINKLE AND A FEW SPOTS COULD BRIEFLY
GO TO MVFR VISIBILITY IN HAZE AROUND DAYBREAK. DRIER AIR WILL
CONTINUE TO MAKER PROGRESS ACROSS NORTHWEST OHIO TONIGHT AND
ACROSS THE ENTIRE FORECAST AREA ON THURSDAY. MVFR CUMULUS CEILINGS
MAY DEVELOP ACROSS INLAND NORTHEAST OHIO FOR A WHILE ON THURSDAY
MORNING AND WILL LIKELY BECOME VFR FAIR WEATHER CUMULUS CEILINGS
AT KCAK AND KYNG BY AFTERNOON. VFR WITH PATCHY PATCHY HIGH CLOUDS
ELSEWHERE ON THURSDAY AS SURFACE HIGH PRESSURE BUILDS IN FROM
THE WEST.
OUTLOOK...NON VFR STARTING LATER FRIDAY AND CONTINUING THROUGH
THE WEEKEND...ESPECIALLY FOR NE OH AND NW PA.
&&
.MARINE...
HAVE CANCELED THE SMALL CRAFT ADVISORY. LATEST GUIDANCE
AND ANALYSIS OF CURRENT CONDITIONS LEADS TOWARD 2 TO OCCASIONALLY 4
FEET OVERNIGHT. THE GRADIENT IS NOT THAT TIGHT AND COLD AIR
ADVECTION NOT STRONG. NORTH FLOW COMES AROUND TO THE NORTHEAST THIS
EVENING AND WILL BE SITTING AT 10 TO 15 KNOTS SUSTAINED. HIGH
PRESSURE WILL STAY NORTH OF THE LAKE ON THURSDAY AND GET SQUEEZED
OUT BY AN APPROACHING COLD FRONT FROM THE NORTHWEST ON FRIDAY. THIS
FRONT WILL HAVE THE POTENTIAL TO CHURN UP THE LAKE WITH STRONG COLD
AIR ADVECTION COMMENCING FRIDAY NIGHT OR SATURDAY MORNING. SMALL
CRAFT ADVISORIES A POSSIBILITY THIS WEEKEND. UPPER LOW STAYS IN THE
VICINITY AND IT WILL BE A COOL AND SHOWERY WEEKEND. WINDS ARE NOT
TOO STRONG ALOFT AND WATERSPOUTS MAY BE POSSIBLE THIS WEEKEND TOO.
HIGH PRESSURE BUILDS ACROSS THE LOWER OHIO VALLEY MONDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...SEFCOVIC
AVIATION...KOSARIK
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
110 AM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE ALONG THE MID-ATLANTIC WILL WEAKEN AS IT MOVES TO THE
SOUTHEASTERN STATES THROUGH MID-WEEK. A SLOW MOVING COLD FRONT OVER
THE CENTRAL GREAT LAKES WILL STALL NORTH OF LAKE ERIE ON TUESDAY. A
WAVE OF LOW PRESSURE WILL MOVE NORTHEAST ALONG THE BOUNDARY ON
WEDNESDAY AND PULL THE FRONT SOUTH ACROSS THE AREA.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
WILL CONTINUE TO IGNORE
THE OVERDONE HRRR AND RAP THAT HAVE BEEN TRYING TO DEVELOP SCT
CONVECTION AROUND THE CWA ALL AFTERNOON AND EVENING.
A SLOW MOVING COLD FRONT IS EXPECTED TO STALL TONIGHT JUST NORTH OF
LAKE ERIE. CONVECTION ALONG THE DIFFERENTIAL HEATING BOUNDARY ON THE
LEADING EDGE OF THE FRONT WILL APPROACH AS THE FRONT SINKS SOUTH BUT
IS GENERALLY EXPECTED TO REMAIN NORTH OF OHIO AS IT OUTPACES THE
FRONT/MOISTURE AXIS WITH SOUTHWESTERLY FLOW THROUGH THE COLUMN
ALOFT. CAN NOT ENTIRELY RULE OUT SOMETHING CLIPPING THE TOLEDO AREA
OR SNEAKING OFF THE LAKE TOWARDS ERIE PA SO WILL CONTINUE WITH A LOW
20 POP IN THOSE AREAS.
DEWPOINTS SHOULD INCH UP IN NORTHWEST OHIO AND WITH INCREASING HIGH
CLOUD WILL KEEP MINS SLIGHTLY WARMER NEAR 70 DEGREES...EXTENDING
EAST ALONG THE LAKESHORE. INLAND NE OHIO WILL BOTTOM OUT IN THE
LOWER TO MID 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
ALTHOUGH SURFACE BOUNDARY AND LARGER SCALE FORCING REMAINS WEST OF
THE AREA ON TUESDAY...ADDED A SLIGHT CHANCE ACROSS NORTHERN COUNTIES
AS LOW LEVEL THETA-E AXIS SINKS SOUTH. EXPECT CONVECTION TO DEVELOP
ACROSS NORTHERN INDIANA AND LOWER MICHIGAN AS SHORTWAVE ENERGY LIFTS
NORTHEAST ACROSS THAT AREA. SOME OF THE UPSTREAM CONVECTION MAY
START TO TRICKLE INTO NORTHWEST OHIO BY EVENING...ESPECIALLY IF
OUTFLOW BOUNDARIES START TO MOVE OUT AHEAD OF THE FRONT SO DID
INCLUDE A CHANCE POP IN NW OHIO AND SLIGHT CHANCE POPS ACROSS THE
NORTHERN COUNTIES. TEMPERATURES WILL BE HOT FOR ONE MORE DAY IN THE
UPPER 80S TO NEAR 90.
A PRETTY GOOD PIECE OF SHORTWAVE ENERGY WILL ROUND THE TROUGH AND
LIFT NORTHEAST ACROSS THE AREA ON WEDNESDAY. THIS OCCURS AS THE
FRONT PUSHES SOUTH AND SHOULD RESULT IN GOOD COVERAGE OF SHOWERS AND
THUNDERSTORMS. KEPT POPS IN THE 60-70 PERCENT RANGE FOR THE DAYTIME
ON WEDNESDAY. SHEAR INCREASES FROM THE WEST LATER IN THE DAY BUT THE
BETTER STORMS MAY BE OUT AHEAD OF THIS AREA WHERE THERE IS MORE
HEATING AND INSTABILITY. NOT INCLUDED IN A SLIGHT RISK AT THIS TIME
BUT COULD ANTICIPATE A FEW STRONG TO SEVERE STORMS IF WE ACHIEVE
SUFFICIENT HEATING. THE CLOUDS AND COVERAGE OF STORMS WILL LIMIT
HIGHS TO THE UPPER 70S TO LOW 80S.
THE FRONT PUSHES SOUTH WEDNESDAY NIGHT AND WE SHOULD DRY OUT ON
THURSDAY. HELD ONTO A LOW CHANCE POP ON THURSDAY IN MOSTLY IN
INTERIOR EASTERN AREAS AS LOW LEVEL DRY AIR PUSHES IN FROM THE
NORTH. TEMPERATURES WILL FINALLY BE BACK CLOSER TO NORMAL VALUES IN
THE LOWER TO MID 70S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE NEXT UPPER LEVEL TROUGH WILL BE DIGGING INTO THE CENTRAL GREAT
LAKES ON FRIDAY. THE EXTENDED MODELS DIFFER IN THE STRENGTH OF THE
STORM SYSTEM MOVING THROUGH THE REGION WHICH WILL HAVE IMPACTS ON
RAIN CHANCES. IN ANY EVENT THERE WILL AT LEAST BE ISOLATED TO
SCATTERED SHOWERS FRIDAY AFTERNOON THROUGH FRIDAY. THE BETTER
CHANCES AT THE MOMENT SEEM TO BE ACROSS NE OHIO AND NW PA.
FRIDAY WILL BE THE WARM DAY OF THE LONG TERM WITH HIGHS INTO THE
MIDDLE 70S AT MOST LOCATIONS. IT WILL THEN BE COOLER SATURDAY INTO
SUNDAY WITH HIGHS GENERALLY WITHIN A COUPLE DEGREES OF 70. A FEW
LOCATIONS COULD SEE LOWS INTO THE 40S SUNDAY MORNING.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
MAINLY HIGH CLOUDS WILL SPREAD EAST INTO THE FORECAST AREA AS THE
DAY PROGRESSES. THEN...THREAT FOR SHOWERS AND THUNDERSTORMS WITH
MVFR VISIBILITIES POSSIBLE AFTER 00Z THIS EVENING IN THE WEST AND
AT ERIE. OTHERWISE...REST OF THE TAF SITES SHOULD REMAIN DRY
THROUGH THE FORECAST PERIOD. EXCEPTION IS CLEVELAND SHOULD SEE
THUNDERSTORM ACTIVITY AFTER 06Z. CEILINGS SHOULD REMAIN
PREDOMINANTLY VFR DURING THE THUNDERSTORMS. WINDS SHOULD BE 10
KNOTS OR LESS FROM THE SOUTH SOUTHWEST.
OUTLOOK...NON VFR LIKELY IN SHRA/TSRA WITH A COLD FRONT WEDNESDAY.
NON VFR MAY LINGER INTO THURSDAY MORNING. NON-VFR POSSIBLE ON
SATURDAY WITH THE NEXT COLD FRONT.
&&
.MARINE...
HIGH PRESSURE WILL CONTINUE TO MOVE SOUTHWARD FROM THE MIDDLE
ATLANTIC STATES. THIS WILL ALLOW A COLD FRONT TO MOVE INTO THE
CENTRAL GREAT LAKES LATE MONDAY INTO TUESDAY. SOUTHWESTERLY WINDS
AHEAD OF THE FRONT WILL INCREASE ON MONDAY INTO TUESDAY. AS THE FRONT
PASSES WEDNESDAY EVENING WEST TO NORTHWEST WINDS MAY TOP OUT IN THE
15 TO 20 KNOT RANGE WHICH WILL GET WAVES CLOSE TO SMALL CRAFT
CRITERIA. IF THIS DOES OCCUR IT WILL BE OVERNIGHT WEDNESDAY NIGHT
INTO THURSDAY MORNING. HIGH PRESSURE WILL THEN BRIEFLY RIDGE ACROSS
LAKE ERIE FROM THE UPPER GREAT LAKES THURSDAY INTO FRIDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...ADAMS
SHORT TERM...KEC
LONG TERM...MULLEN
AVIATION...LOMBARDY
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS TULSA OK
1153 PM CDT MON SEP 7 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
For the 6Z TAFs, VFR conditions will prevail at all sites
throughout the forecast period. Thunderstorm chances will
increase during the afternoon at northern TAF sites as a cold
front approaches from the north. As the cold front moves into the
region Tuesday night, thunderstorm chances will spread to all TAF
sites.
&&
.PREV DISCUSSION... /ISSUED 831 PM CDT MON SEP 7 2015/
UPDATE...
Pops have been removed for the evening hours and the heat headline
has been cancelled. See discussion below.
DISCUSSION...
Temps have cooled with the loss of daytime heating and thus the
heat headline was cancelled. The isolated showers and storms have
also dissipated...and thus pops have been removed for the
evening. Will take a look at the 00z data to determine whether
pops may be needed to the north and west of Tulsa late tonight.
The latest runs of the HRRR do indicate that some high based
activity will slide east along the KS/OK border tonight.
Lacy
PREV DISCUSSION... /ISSUED 610 PM CDT MON SEP 7 2015/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
For the 0Z TAFs, VFR conditions will prevail at all sites
throughout the 24 hour forecast period. Thunderstorm chances will
increase during the afternoon at our northern TAF sites as a cold
front approaches from the north. Frontal passage will be after
this forecast period.
PREV DISCUSSION... /ISSUED 338 PM CDT MON SEP 7 2015/
DISCUSSION...
Late summer heat will continue into Tuesday with the forecast
trended warmer despite the potential for more extensive cloud
cover tomorrow. Convection will develop across southern KS
tomorrow afternoon and spread southeastward by late afternoon and
early evening. Forecast soundings have steep low level lapse rates
amid a plume of 1.75-2 inch precip water with decreasing deep
layer shear w/ southward extent. This would favor downburst
potential and potential aggressive outflow winds w/ the strongest
storms. This potential will also keep northern locations from
otherwise being just as hot tomorrow.
The actual frontal boundary will become the focus for widespread evening
and overnight convection w/ a trend away from severe weather
potential and more toward locally heavy rain. The boundary will
focus precip toward southern areas Wednesday...with the post
frontal air being cooler but not much drier initially.
The stronger push of drier air arrives late Thurs-Friday
associated with another passing wave. A brief shot of precip may
accompany this wave otherwise dry and pleasant conditions look
likely for next weekend. The GFS is an outlier at this range w/
regards to precip potential and favored the GEM/ECMWF solutions.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...06
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1123 PM EDT WED SEP 9 2015
.SYNOPSIS...
A COLD FRONT HAS MOVED THROUGH MOST OF THE STATE BUT MAY LINGER
OVER FAR SOUTHERN AND SOUTHEASTERN PA OVERNIGHT. A WAVE OF LOW
PRESSURE WILL FORM ALONG THE FRONT TO OUR SOUTH AND TRACK ACROSS
THE DELMARVA PENINSULA THURSDAY...BRINGING A MUCH COOLER AND
SHOWERY DAY TO MOST OF CENTRAL PENNSYLVANIA. A CUT OFF LOW WILL
DEVELOP OVER THE OHIO VALLEY AND SLOWLY LIFT NORTHEAST ACROSS
PENNSYLVANIA THIS WEEKEND.
&&
.NEAR TERM /UNTIL 7 AM THURSDAY MORNING/...
RECENT RUNS OF HRRRRR AND RAP HAVE BEEN CONSISTENT IN PRODUCING
CONVECTION/PRECIP IN THE SE THROUGH THE NEXT 3-4 HOURS AS THE
FRONT PRESSES THROUGH THERE. SEEMS REASONABLE NOW THAT IT IS
ACTUALLY FLARING UP OVER THE EC/SE. THUS...HAVE DRAWN HIGHER-END
POPS IN THE SERN QUARTER OF THE AREA BUT TAPERED THEM OFF TOWARD
MORNING. OPPOSITE TREND IN THE SW WHERE IT IS QUIET NOW BUT
CONVECTION IN SRN WV IS A TIP TO THE POSSIBILITY OF RAIN/SHOWERS
MOVING BACK IN BEFORE DAWN. WILL RAMP UP THE POPS IN THE SW TO 100
BEFORE 12Z. FOG IS POSSIBLE ACROSS THE N/NW WHERE CLOUDS ARE
CURRENTLY LACKING. IT MAY CLOUD BACK UP...BUT THE DEWPOINTS SHOULD
BE DROPPING AS THE AIR COOLS OFF TOO.
THE WAVE DEVELOPING TONIGHT TO THE SOUTH OF THE STATE WILL THROW
THE BRAKE SWITCH ON THE STEADY MOVEMENT OF THE FRONT AND THE PLUME
OF DEEP /2 INCH+ PWATS/ STREAMING OVERHEAD. THUS...SHOWERS MAY
INITIALLY DECREASE IN COVERAGE THIS EVENING AND EARLY TONIGHT WILL
LIKELY COME BACK IN FROM THE SOUTH LATER TONIGHT.
&&
.SHORT TERM /7 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
THURSDAY LOOKS TO BE A SHOWERY DAY ACROSS MOST OF CENTRAL PA AS A
WAVE RIPPLES ALONG THE NEARLY STATIONARY FRONTAL ZONE AND DELIVERS
MUCH NEEDED RAINFALL TO MUCH OF CENTRAL AND SOUTHERN PA. THE FAR
NORTH MAY ESCAPE THE STEADIEST RAINFALL BUT SHOWERS WILL STILL BE
POSSIBLE UP TO THE NY BORDER THROUGH MIDDAY.
CLOUD COVER...RAINFALL AND LOW LVL COLD ADVECTION NORTH OF THE
STALLED FRONTAL BOUNDARY WILL BRING A MUCH COOLER DAY. BIGGEST
QUESTION IS HOW COOL AS CONVECTIVE PARAMETERIZATIONS OF COARSER
MODELS KEEP THINGS UNREALISTICALLY COOL FOR THE GIVEN BOUNDARY
LAYER TEMPERATURES. WENT WITH A COMPROMISE AND SPLIT THE
DIFFERENCE HEDGING TOWARDS THE WARMER 850 MB TEMPS BUT ADJUSTING
FOR CAD AND LITTLE IF ANY SUNSHINE ALONG WITH NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS...YIELDING UPPER 60S FOR MAXES ACROSS THE
RIDGES AND LOWER TO MID 70S ELSEWHERE (WARMEST READINGS LOWER
SUSQ). A GOOD PART OF CENTRAL PA WILL STRUGGLE TO HIT 70 AFTER
SEEING THE WARMEST READINGS OF SUMMER THE LAST 2 DAYS. SHOWERS
WILL DECREASE ACROSS THE CENTRAL MOUNTAINS IN THE AFTERNOON...AND
LINGER INTO THE EVENING OVER THE LOWER SUSQ.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
CONFIDENCE IN FAIR WX FRIDAY CONTINUES TO INCREASE AS ALL MDL
DATA INDICATING CENTRAL PA WILL BE UNDER WEAK RIDGING BTWN
DEPARTING COASTAL LOW AND DEEPENING UPPER LEVEL LOW THAT ALL MID
RANGE MODELS ARE NOW SHOWING A CUT OFF LOW. THIS BRIEF RESPITE
SHOULD ALLOW FOR THE REGION TO HAVE ABUNDANT SUNSHINE THAT SHOULD
HELP TEMPS RECOVER TO NR SEASONAL READINGS IN THE 70S.
THE CUT OFF LOW THAT SHOULD FORM OVER THE OHIO VALLEY WILL MOVE
THROUGH SATURDAY...THEN TRACK NORTHEAST ACROSS PA LATE IN THE
WEEKEND. THIS SCENARIO SHOULD BRING A PERIOD OF COOL/SHOWERY WX
SAT-SUN. HOWEVER...ECENS AND GEFS BOTH LIFT OUT UPPER TROF EARLY
NEXT WEEK...REPLACING IT WITH A BUILDING UPPER LVL RIDGE OVR THE
EAST COAST BY MID TO LATE NEXT WEEK. THUS...FAIR AND WARMER WX
APPEARS VERY LIKELY LATER NEXT WEEK.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
03Z TAFS SENT. SOME ADJUSTMENTS MADE.
EARLIER DISCUSSION BELOW.
LINE OF STORMS FORMED JUST SOUTH OF THE OFFICE BY A FEW
HUNDRED YARDS.
EXPECT SEVERAL MORE HOURS OF STORMS.
MUCH OF THE NIGHT MAY FEATURE VFR CIGS WITH VCSH.
AS FRONT STALLS AND WEAK WAVE LIFTS NE...MORE IN THE WAY OF
WIDESPREAD SHOWERS WILL OCCUR FROM SW TO NE LATE TONIGHT INTO
THU.
SOME CLEARING FROM WEST TO EAST LATE THU.
COMPLEX PATTERN FOR LATE IN THE WEEK INTO THE WEEKEND.
OUTLOOK...
THU...MORE NUMEROUS SHRA/TSRA EXPECTED. BRIEF IFR CIGS AND VSBYS
POSSIBLE.
FRI...PATCHY MORNING FOG POSSIBLE...OTHERWISE GENERALLY VFR.
SAT...SCATTERED SHRA/TSRA.
SUN...SCATTERED SHOWERS...MAINLY EASTERN AREAS.
MON...MORNING VALLEY FOG...OTHERWISE BECOMING VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR/FITZGERALD
NEAR TERM...DANGELO
SHORT TERM...DEVOIR/FITZGERALD
LONG TERM...FITZGERALD/CERU
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1022 PM EDT WED SEP 9 2015
.SYNOPSIS...
A COLD FRONT HAS MOVED THROUGH MOST OF THE STATE BUT MAY LINGER
OVER FAR SOUTHERN AND SOUTHEASTERN PA OVERNIGHT. A WAVE OF LOW
PRESSURE WILL FORM ALONG THE FRONT TO OUR SOUTH AND TRACK ACROSS
THE DELMARVA PENINSULA THURSDAY...BRINGING A MUCH COOLER AND
SHOWERY DAY TO MOST OF CENTRAL PENNSYLVANIA. A CUT OFF LOW WILL
DEVELOP OVER THE OHIO VALLEY AND SLOWLY LIFT NORTHEAST ACROSS
PENNSYLVANIA THIS WEEKEND.
&&
.NEAR TERM /UNTIL 7 AM THURSDAY MORNING/...
RECENT RUNS OF HRRRRR AND RAP HAVE BEEN CONSISTENT IN PRODUCING
CONVECTION/PRECIP IN THE SE THROUGH THE NEXT 3-4 HOURS AS THE
FRONT PRESSES THROUGH THERE. SEEMS REASONABLE NOW THAT IT IS
ACTUALLY FLARING UP OVER THE EC/SE. THUS...HAVE DRAWN HIGHER-END
POPS IN THE SERN QUARTER OF THE AREA BUT TAPERED THEM OFF TOWARD
MORNING. OPPOSITE TREND IN THE SW WHERE IT IS QUIET NOW BUT
CONVECTION IN SRN WV IS A TIP TO THE POSSIBILITY OF RAIN/SHOWERS
MOVING BACK IN BEFORE DAWN. WILL RAMP UP THE POPS IN THE SW TO 100
BEFORE 12Z. FOG IS POSSIBLE ACROSS THE N/NW WHERE CLOUDS ARE
CURRENTLY LACKING. IT MAY CLOUD BACK UP...BUT THE DEWPOINTS SHOULD
BE DROPPING AS THE AIR COOLS OFF TOO.
THE WAVE DEVELOPING TONIGHT TO THE SOUTH OF THE STATE WILL THROW
THE BRAKE SWITCH ON THE STEADY MOVEMENT OF THE FRONT AND THE PLUME
OF DEEP /2 INCH+ PWATS/ STREAMING OVERHEAD. THUS...SHOWERS MAY
INITIALLY DECREASE IN COVERAGE THIS EVENING AND EARLY TONIGHT WILL
LIKELY COME BACK IN FROM THE SOUTH LATER TONIGHT.
&&
.SHORT TERM /7 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
THURSDAY LOOKS TO BE A SHOWERY DAY ACROSS MOST OF CENTRAL PA AS A
WAVE RIPPLES ALONG THE NEARLY STATIONARY FRONTAL ZONE AND DELIVERS
MUCH NEEDED RAINFALL TO MUCH OF CENTRAL AND SOUTHERN PA. THE FAR
NORTH MAY ESCAPE THE STEADIEST RAINFALL BUT SHOWERS WILL STILL BE
POSSIBLE UP TO THE NY BORDER THROUGH MIDDAY.
CLOUD COVER...RAINFALL AND LOW LVL COLD ADVECTION NORTH OF THE
STALLED FRONTAL BOUNDARY WILL BRING A MUCH COOLER DAY. BIGGEST
QUESTION IS HOW COOL AS CONVECTIVE PARAMETERIZATIONS OF COARSER
MODELS KEEP THINGS UNREALISTICALLY COOL FOR THE GIVEN BOUNDARY
LAYER TEMPERATURES. WENT WITH A COMPROMISE AND SPLIT THE
DIFFERENCE HEDGING TOWARDS THE WARMER 850 MB TEMPS BUT ADJUSTING
FOR CAD AND LITTLE IF ANY SUNSHINE ALONG WITH NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS...YIELDING UPPER 60S FOR MAXES ACROSS THE
RIDGES AND LOWER TO MID 70S ELSEWHERE (WARMEST READINGS LOWER
SUSQ). A GOOD PART OF CENTRAL PA WILL STRUGGLE TO HIT 70 AFTER
SEEING THE WARMEST READINGS OF SUMMER THE LAST 2 DAYS. SHOWERS
WILL DECREASE ACROSS THE CENTRAL MOUNTAINS IN THE AFTERNOON...AND
LINGER INTO THE EVENING OVER THE LOWER SUSQ.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
CONFIDENCE IN FAIR WX FRIDAY CONTINUES TO INCREASE AS ALL MDL
DATA INDICATING CENTRAL PA WILL BE UNDER WEAK RIDGING BTWN
DEPARTING COASTAL LOW AND DEEPENING UPPER LEVEL LOW THAT ALL MID
RANGE MODELS ARE NOW SHOWING A CUT OFF LOW. THIS BRIEF RESPITE
SHOULD ALLOW FOR THE REGION TO HAVE ABUNDANT SUNSHINE THAT SHOULD
HELP TEMPS RECOVER TO NR SEASONAL READINGS IN THE 70S.
THE CUT OFF LOW THAT SHOULD FORM OVER THE OHIO VALLEY WILL MOVE
THROUGH SATURDAY...THEN TRACK NORTHEAST ACROSS PA LATE IN THE
WEEKEND. THIS SCENARIO SHOULD BRING A PERIOD OF COOL/SHOWERY WX
SAT-SUN. HOWEVER...ECENS AND GEFS BOTH LIFT OUT UPPER TROF EARLY
NEXT WEEK...REPLACING IT WITH A BUILDING UPPER LVL RIDGE OVR THE
EAST COAST BY MID TO LATE NEXT WEEK. THUS...FAIR AND WARMER WX
APPEARS VERY LIKELY LATER NEXT WEEK.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
LINE OF STORMS FORMED JUST SOUTH OF THE OFFICE BY A FEW HUNDRED
YARDS.
EXPECT SEVERAL MORE HOURS OF STORMS.
MUCH OF THE NIGHT MAY FEATURE VFR CIGS WITH VCSH.
AS FRONT STALLS AND WEAK WAVE LIFTS NE...MORE IN THE WAY OF
WIDESPREAD SHOWERS WILL OCCUR FROM SW TO NE LATE TONIGHT INTO
THU.
SOME CLEARING FROM WEST TO EAST LATE THU.
COMPLEX PATTERN FOR LATE IN THE WEEK INTO THE WEEKEND.
OUTLOOK...
THU...MORE NUMEROUS SHRA/TSRA EXPECTED. BRIEF IFR CIGS AND VSBYS
POSSIBLE.
FRI...PATCHY MORNING FOG POSSIBLE...OTHERWISE GENERALLY VFR.
SAT...SCATTERED SHRA/TSRA.
SUN...SCATTERED SHOWERS...MAINLY EASTERN AREAS.
MON...MORNING VALLEY FOG...OTHERWISE BECOMING VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR/FITZGERALD
NEAR TERM...DANGELO
SHORT TERM...DEVOIR/FITZGERALD
LONG TERM...FITZGERALD/CERU
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
752 AM EDT TUE SEP 8 2015
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH EARLY
WEDNESDAY. A SLOW-MOVING COLD FRONT WILL THEN PRESS SOUTHEAST
ACROSS THE AREA LATE WEDNESDAY AND THURSDAY. A DEEPENING UPPER
LEVEL TROUGH AND ASSOCIATED COLD FRONT WILL LIKELY PUSH THROUGH
PENNSYLVANIA NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
11-3.9U IMAGERY SHOWING SOME PATCHY DENSE FOG IN THE DEEP VALLEYS
NORTH OF I-80 EARLY THIS MORNING. THE FOG SHOULD BURN OFF BY ARND
13Z PER LATEST HRRR/LAMP. CENTRAL PA WILL REMAIN BENEATH UPPER RIDGE
AXIS TODAY...WITH LARGE SCALE SUBSIDENCE AND RELATIVELY LOW PWATS
LIKELY ENSURING A MSUNNY...HOT AND DRY DAY. CAN/T COMPLETELY RULE
OUT AN ISOLD LATE DAY SHOWER OVR THE ELEVATED HEAT SOURCE OF THE
LAUREL HIGHLANDS AS LATEST HRRR SUGGESTS. HOWEVER...BELIEVE AREAL
COVERAGE OF ANY SHOWERS WOULD BE TOO LOW TO MENTION IN GRIDS
ATTM.
TEMPS SHOULD BE AT LEAST AS WARM AS YESTERDAY OR PERHAPS EVEN A
DEG OR TWO HIGHER BASED ON GEFS MEAN 925/850 TEMPS. MAXES WILL
RANGE FROM THE U80S ACROSS THE ALLEGHENY PLATEAU...TO THE L90S
ACROSS THE SUSQ VALLEY. RECORD HIGH OF 92F AT KIPT COULD BE IN
JEOPARDY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
AFTER ANOTHER VERY WARM AND TRANQUIL NIGHT...APPROACHING SHORTWAVE
AND ASSOC COLD FRONT WILL BRING A CHANCE OF SHRA/TSRA WEDNESDAY.
HIGHEST /LIKELY/ POPS ARE PAINTED ACROSS THE NW MTNS CLOSEST TO
APPROACHING COLD FRONT. ALL SHORT RANGE MDLS INDICATE THERE WILL
BE A MINIMUM IN SHOWER ACTIVITY ACROSS THE CENTRAL MTNS IN
CONJUNCTION WITH LINGERING RIBBON OF LOWER PWATS.
PARTLY CLOUDY SKIES AND SCT PM CONVECTION MAY HOLD TEMPS DOWN A
BIT FROM RECENT DAYS. HOWEVER...AIR MASS REMAINS VERY WARM WITH
MDL 8H TEMPS AOA 18C. THEREFORE...EXPECT HIGHS WELL INTO THE
80S...WITH 90F STILL POSSIBLE ACROSS THE SUSQ VALLEY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
MED RANGE MDLS ALL INDICATING INITIAL SHORTWAVE SHEARS OUT AND
LIFTS NORTH OF PA WED NIGHT. TRAILING...SLOW-MOVING COLD FRONT
SHOULD PUSH THRU CENTRAL PA WED NITE/THURSDAY. EXPECT SOME
BENEFICIAL RAINFALL OVR MOST OF THE AREA FROM THIS FEATURE AS
FRONT INTERACTS WITH HIGH MOISTURE/PWAT ANOMALIES. BLEND OF LATEST
ENSEMBLE OUTPUT SUPPORTS WIDESPREAD 0.25 TO 0.50 INCHES...WITH
LOCAL AMTS IN EXCESS OF AN INCH.
A RETURN TO FAIR WX/SEASONAL TEMPS APPEARS LIKELY FRIDAY IN WAKE
OF FRONT. HOWEVER...DIGGING TROF AND ASSOC SECONDARY COLD FRONT
APPEARS LIKELY TO SWING THRU CENTRAL PA OVER THE WEEKEND...BRINING
ANOTHER ROUND OF SHOWERY CONDS. ECENS AND OPER CANADIAN FORMING A
CUT OFF LOW OVR THE OHIO VALLEY...SIGNALING THE UNSETTLED WX COULD
LAST THRU MOST OF THE WEEKEND.
TEMPS MAY BRIEFLY FALL BLW NORMAL ARND SUN-MON...AS UPPER LOW
LIFTS THRU. HOWEVER...LATEST ECENS/NAEFS SUPPORT A RETURN TO ABOVE
NORMAL TEMPS NEXT WEEK...AS TROUGH QUICKLY LIFTS OUT AND UPPER RIDGE
BUILDS ALONG THE EAST COAST.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AREAS OF MVFR VSBYS IN FOG WILL DISSIPATE BY 13-14Z...LEAVING
ANOTHER DAY OF PREDOMINANTLY VFR CONDS. A STRAY LATE- DAY
SHRA/TSRA IS AGAIN POSSIBLE ACROSS THE NW MTNS...BUT THAT IS ABOUT
IT. WINDS WILL BE NEARLY CALM THIS MORNING...THEN BECOME LIGHT
OUT OF THE SW BY AFTN.
THINGS WILL TURN A BIT MORE UNSETTLED FOR THE SECOND HALF OF THE
WEEK...AS A COLD FRONT APPROACHES FROM THE GREAT LAKES WEDNESDAY
AND CROSSES PA ON THURSDAY.
OUTLOOK...
WED...SCATTERED LATE-DAY SHRA/TSRA POSSIBLE.
THU...MORE NUMEROUS SHRA/TSRA EXPECTED.
FRI...PATCHY MORNING FOG POSSIBLE...OTHERWISE GENERALLY VFR.
SAT...WIDELY SCATTERED LATE-DAY SHRA/TSRA POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/CERU
AVIATION...GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
602 AM EDT TUE SEP 8 2015
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH EARLY
WEDNESDAY. A SLOW-MOVING COLD FRONT WILL THEN PRESS SOUTHEAST
ACROSS THE AREA LATE WEDNESDAY AND THURSDAY. A DEEPENING UPPER
LEVEL TROUGH AND ASSOCIATED COLD FRONT WILL LIKELY PUSH THROUGH
PENNSYLVANIA NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
11-3.9U IMAGERY SHOWING SOME PATCHY DENSE FOG IN THE DEEP VALLEYS
NORTH OF I-80 EARLY THIS MORNING. THE FOG SHOULD BURN OFF BY ARND
13Z PER LATEST HRRR/LAMP. CENTRAL PA WILL REMAIN BENEATH UPPER RIDGE
AXIS TODAY...WITH LARGE SCALE SUBSIDENCE AND RELATIVELY LOW PWATS
LIKELY ENSURING A MSUNNY...HOT AND DRY DAY. CAN/T COMPLETELY RULE
OUT AN ISOLD LATE DAY SHOWER OVR THE ELEVATED HEAT SOURCE OF THE
LAUREL HIGHLANDS AS LATEST HRRR SUGGESTS. HOWEVER...BELIEVE AREAL
COVERAGE OF ANY SHOWERS WOULD BE TOO LOW TO MENTION IN GRIDS
ATTM.
TEMPS SHOULD BE AT LEAST AS WARM AS YESTERDAY OR PERHAPS EVEN A
DEG OR TWO HIGHER BASED ON GEFS MEAN 925/850 TEMPS. MAXES WILL
RANGE FROM THE U80S ACROSS THE ALLEGHENY PLATEAU...TO THE L90S
ACROSS THE SUSQ VALLEY. RECORD HIGH OF 92F AT KIPT COULD BE IN
JEOPARDY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
AFTER ANOTHER VERY WARM AND TRANQUIL NIGHT...APPROACHING SHORTWAVE
AND ASSOC COLD FRONT WILL BRING A CHANCE OF SHRA/TSRA WEDNESDAY.
HIGHEST /LIKELY/ POPS ARE PAINTED ACROSS THE NW MTNS CLOSEST TO
APPROACHING COLD FRONT. ALL SHORT RANGE MDLS INDICATE THERE WILL
BE A MINIMUM IN SHOWER ACTIVITY ACROSS THE CENTRAL MTNS IN
CONJUNCTION WITH LINGERING RIBBON OF LOWER PWATS.
PARTLY CLOUDY SKIES AND SCT PM CONVECTION MAY HOLD TEMPS DOWN A
BIT FROM RECENT DAYS. HOWEVER...AIR MASS REMAINS VERY WARM WITH
MDL 8H TEMPS AOA 18C. THEREFORE...EXPECT HIGHS WELL INTO THE
80S...WITH 90F STILL POSSIBLE ACROSS THE SUSQ VALLEY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
MED RANGE MDLS ALL INDICATING INITIAL SHORTWAVE SHEARS OUT AND
LIFTS NORTH OF PA WED NIGHT. TRAILING...SLOW-MOVING COLD FRONT
SHOULD PUSH THRU CENTRAL PA WED NITE/THURSDAY. EXPECT SOME
BENEFICIAL RAINFALL OVR MOST OF THE AREA FROM THIS FEATURE AS
FRONT INTERACTS WITH HIGH MOISTURE/PWAT ANOMALIES. BLEND OF LATEST
ENSEMBLE OUTPUT SUPPORTS WIDESPREAD 0.25 TO 0.50 INCHES...WITH
LOCAL AMTS IN EXCESS OF AN INCH.
A RETURN TO FAIR WX/SEASONAL TEMPS APPEARS LIKELY FRIDAY IN WAKE
OF FRONT. HOWEVER...DIGGING TROF AND ASSOC SECONDARY COLD FRONT
APPEARS LIKELY TO SWING THRU CENTRAL PA OVER THE WEEKEND...BRINING
ANOTHER ROUND OF SHOWERY CONDS. ECENS AND OPER CANADIAN FORMING A
CUT OFF LOW OVR THE OHIO VALLEY...SIGNALING THE UNSETTLED WX COULD
LAST THRU MOST OF THE WEEKEND.
TEMPS MAY BRIEFLY FALL BLW NORMAL ARND SUN-MON...AS UPPER LOW
LIFTS THRU. HOWEVER...LATEST ECENS/NAEFS SUPPORT A RETURN TO ABOVE
NORMAL TEMPS NEXT WEEK...AS TROUGH QUICKLY LIFTS OUT AND UPPER RIDGE
BUILDS ALONG THE EAST COAST.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
UNDER A MAINLY CLEAR SKY...PATCHY FOG IS POSSIBLE OVERNIGHT. AS
WAS THE CASE SUNDAY NIGHT...KBFD IS ONCE AGAIN THE TAF SITE MOST
LIKELY TO BE SIGNIFICANTLY AFFECTED.
ANY FOG WILL BURN OFF TUES AM...LEAVING ANOTHER DAY OF
PREDOMINANTLY VFR CONDS. A STRAY LATE-DAY SHRA/TSRA IS AGAIN
POSSIBLE ACROSS THE NW MTNS...BUT THAT IS ABOUT IT. WINDS WILL BE
NEARLY CALM TO START THE DAY...THEN BECOME LIGHT OUT OF THE SW BY
AFTN.
THINGS WILL TURN A BIT MORE UNSETTLED FOR THE SECOND HALF OF THE
WEEK...AS A COLD FRONT APPROACHES FROM THE GREAT LAKES WEDNESDAY
AND CROSSES PA ON THURSDAY.
OUTLOOK...
WED...SCATTERED LATE-DAY SHRA/TSRA POSSIBLE.
THU...MORE NUMEROUS SHRA/TSRA EXPECTED.
FRI...PATCHY MORNING FOG POSSIBLE...OTHERWISE GENERALLY VFR.
SAT...WIDELY SCATTERED LATE-DAY SHRA/TSRA POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/CERU
AVIATION...GARTNER/EVANEGO
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
917 PM CDT WED SEP 9 2015
.DISCUSSION...
A WEAK 1012 MB SURFACE LOW IS SITUATED OVER WEST TN/NRN MS THIS
EVENING. BEST LIFT AND DEEPER MOISTURE IS PUSHING EAST INTO
MIDDLE TN. AREAL COVERAGE OF PRECIP IS RAPIDLY DIMINISHING WITH
JUST A FEW SHOWERS OVER PARTS OF WEST TN ATTM. CLEARING IS ALREADY
WORKING INTO PARTS OF NE AR. LATEST HRRR INDICATING THAT SHOWERS
AND THUNDERSTORMS MAY REDEVELOP ACROSS PARTS OF NORTH MS LATER
TONIGHT AS ANOTHER PIECE OF UPPER LEVEL ENERGY MOVES THROUGH. LEFT
LIKELY POPS WITH A MENTION OF THUNDER IN THAT AREA AFTER
MIDNIGHT. OTRW TENDED TO TRIM POPS AND ADDED A MENTION OF FOG
ESPECIALLY IN AREAS THAT WILL CLEAR OUT ACROSS NE AR.
SJM
&&
PREV DISCUSSION... /ISSUED 237 PM CDT WED SEP 9 2015/
WIDESPREAD RAIN AND THUNDERSTORMS ARE ONGOING ACROSS MUCH OF THE
MIDSOUTH. FORTUNATELY THEY ARE SUB SEVERE...BUT WE HAVE ISSUED A
COUPLE OF FLASH FLOOD WARNINGS DUE TO LOCALLY HEAVY RAIN IN THE
MEMPHIS AND SURROUNDING METROPOLITAN AREAS. DOPPLER RADAR
ESTIMATES NEAR 4 INCHES OF RAIN HAS FALLEN IN THESE AREAS...WITH
ANOTHER ROUND OR TWO OF HEAVY RAIN POSSIBLE THIS AFTERNOON. ALL OF
THIS RAIN IS FALLING AS A COLD FRONT MOVES SLOWLY ACROSS THE
MIDSOUTH. ITS EXACT LOCATION IS MASKED BY RAIN COOLED AIR AND
OUTFLOW BOUNDARIES...BUT IT LOOKS TO HAVE SHIFTED SOUTH OF THE
INTERSTATE 40 CORRIDOR. TEMPERATURES RANGE FROM THE MIDDLE 80S IN
NORTHEAST MISSISSIPPI TO THE LOW 70S IN NORTHEAST ARKANSAS. THE
FRONT WILL CONTINUE TO SHIFT SLOWLY TO THE SOUTH TONIGHT...WITH
THUNDERSTORMS POSSIBLE MAINLY ALONG AND SOUTH OF THE FRONT...AND
LIGHTER RAIN SHOWERS TO THE NORTH.
TOMORROW WE MAY SEE BRIEF CLEARING...BUT A SECONDARY COLD FRONT IS
EXPECTED TO BRING MORE RAIN AND WEAK THUNDERSTORMS TO THE MIDSOUTH
TOMORROW EVENING...CONTINUING INTO FRIDAY. DEW POINTS AND
TEMPERATURES ARE NOT EXPECTED TO COOL SIGNIFICANTLY UNTIL AT LEAST
MIDDAY FRIDAY...SO UNTIL THEN THUNDERSTORMS WILL REMAIN A
POSSIBILITY. NONE ARE EXPECTED TO BE SEVERE. AS THE SECONDARY COLD
FRONT SHIFTS ACROSS THE MIDSOUTH FRIDAY...RAIN CHANCES WILL
DIMINISH QUICKLY AND WINDS WILL SHIFT FROM THE NORTH. PORTIONS OF
THE MIDSOUTH...ESPECIALLY EAST ARKANSAS AND WEST TENNESSEE MAY SEE
HIGH TEMPERATURES BEFORE NOON...WITH STEADY OR FALLING
TEMPERATURES DURING THE AFTERNOON.
OVER THE WEEKEND...EXPECT FALL LIKE CONDITIONS. AFTERNOON HIGHS
WILL BE IN THE LOW TO MIDDLE 70S ACROSS MOST OF THE MIDSOUTH UNDER
MOSTLY CLEAR SKIES. TEMPERATURES WILL TREND WARMER DURING THE
EARLY TO MIDDLE PART OF NEXT WEEK. HIGHS WILL BE BACK IN THE
MIDDLE TO UPPER 70S BY WEDNESDAY. NO SIGNIFICANT RAIN CHANCES ARE
EXPECTED TO RETURN TO THE MIDSOUTH UNTIL WEDNESDAY AT THE
EARLIEST.
30
&&
.AVIATION...
00Z TAF CYCLE
LIGHT RAIN CONTINUES TO FALL OVER EASTERN SECTIONS OF THE FORECAST
AREA AND SHOULD BE EXITING THE REGION LATER THIS EVENING. CEILINGS
WILL LIFT TO VFR LEVELS FOR A FEW HOURS THIS EVENING BEFORE LOW
CLOUDS WILL RETURN OVERNIGHT. PATCHY FOG IS EXPECTED OVERNIGHT AS
WELL. SOME SCATTERED SHOWERS MAY OCCUR DURING THE MORNING HOURS ON
THURSDAY BEFORE VFR CONDITIONS RETURN BY THE AFTERNOON. WINDS WILL
BE MAINLY FROM THE NORTH AT 5 TO 10 KNOTS FOR MUCH OF THE FORECAST
PERIOD.
ARS
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS AMARILLO TX
242 PM CDT TUE SEP 8 2015
.DISCUSSION...
LATEST SURFACE OBS SHOWS THE COLD FRONT EXTENDING FROM JUST NORTH OF
WHEELER SOUTHWESTWARD TO NEAR CLAUDE. MORNING SOUNDING INDICATES
CONSIDERABLE MOISTENING IN THE MID LEVELS AS EVIDENT BY WIDESPREAD
ALTOSTRATUS OBSERVED ACROSS MOST OF THE AREA. POST FRONTAL AIR MASS
IS RELATIVELY COOL ESPECIALLY WHERE MID CLOUDS ARE MOST EXTENSIVE.
TEMPERATURES AT 19Z RANGE FROM THE MID 70S TO THE MID 80S BEHIND THE
FRONT. DESPITE MOIST ADVECTION BEHIND THE FRONT IN THE
NORTHEAST...DIABATIC HEATING HAS BEEN INSUFFICIENT FOR MEANINGFUL
INSTABILITY TO DEVELOP. TEMPERATURES WERE NEAR 100 DEGREES IN THE
FAR SOUTHEAST WHERE SOUTHWESTERLY SURFACE WINDS PREVAIL AND CLOUD
COVER HAS BEEN LIMITED. THIS IS WHERE INSTABILITY HAS INCREASED THE
MOST AND GIVEN LOW/MID 60 DEGREE DEW POINTS MODERATE INSTABILITY HAS
DEVELOPED DESPITE WEAK MID LEVEL LAPSE RATES. SO FAR CONVECTION HAS
BEEN RELATIVELY BENIGN AND CONFINED MOSTLY TO ALONG AND JUST BEHIND
THE FRONT ACROSS EAST CENTRAL AND NORTHEAST PORTIONS OF THE TEXAS
PANHANDLE. SOME INTENSIFICATION SHOULD OCCUR LATER THIS AFTERNOON BUT
CHANCES WILL DECREASE FAIRLY QUICKLY LATER THIS AFTERNOON AND
ESPECIALLY BY EVENING AS LIFT ASSOCIATED WITH A WEAK SHORTWAVE SHIFTS
EASTWARD INTO OKLAHOMA. THIS SHORTWAVE IS DIFFICULT TO SEE BUT SOME
INDICATION IN WATER VAPOR IMAGERY AND RAP PV ANALYSIS SUPPORTS TRENDS
SEEN ON RADAR.
MODERATE INSTABILITY IN THE SOUTHEAST AND EAST CENTRAL TEXAS
PANHANDLE RAISES SOME CONCERN FOR SEVERE POTENTIAL. A MISALIGNMENT
OF BEST SHEAR BEHIND THE FRONT (WHERE NORTHERLY/NORTHEASTERLY FLOW
EXISTS) FROM THE MOST SIGNIFICANT INSTABILITY SOUTHEAST OF THE FRONT
IS A NEGATIVE FACTOR. WEAKLY ORGANIZED UPDRAFTS IN THE SOUTHEAST PART
OF THE TEXAS PANHANDLE THROUGH THE AFTERNOON INTO THE EARLY EVENING
COULD RESULT IN BRIEF/ISOLATED MARGINALLY SEVERE HAIL OR WIND GUSTS.
LOCALLY HEAVY RAIN WILL BE POSSIBLE GIVEN MODEST STORM MOTIONS AND A
MOIST ENVIRONMENT WITH PWATS AROUND AN INCH AND A HALF.
HAVE SCALED BACK PRECIPITATION PROBABILITIES LATER TONIGHT BASED ON
TRENDS AND AM QUITE CONFIDENT IN A DRY FORECAST FOR TOMORROW. POST
FRONTAL ENVIRONMENT WILL BE COOLER BUT ONLY SLIGHTLY BELOW NORMAL
VALUES FOR EARLY TO MID SEPTEMBER. DURING THE MID WEEK PERIOD BROAD
CYCLONIC FAIRLY SWIFT MID/UPPER FLOW WILL COVER MUCH OF THE NORTHERN
PORTIONS OF THE COUNTRY. OVERALL NOT MUCH CHANGE WAS MADE TO THE
PREVIOUS FORECAST. THE CHALLENGE WILL SHIFT TOWARD RESOLVING FAST
MOVING SHORTWAVE TROUGHS EMBEDDED WITHIN THE LARGER UPPER LOW OVER
EASTERN CANADA THROUGH THE END OF THE WEEK. MODELS BRING THE FIRST
WAVE THROUGH THE CENTRAL PLAINS LATE THURSDAY THROUGH EARLY FRIDAY
FORCING ANOTHER COLD FRONT THROUGH. CONTINUED THE TREND OF
DOWNPLAYING DAYTIME PRECIPITATION CHANCES ACROSS MUCH OF THE REGION
EXPECT THE NORTHERN TEXAS PANHANDLE AND OKLAHOMA PANHANDLE. CHANCES
SPREAD SOUTH THROUGH THE NIGHT. GIVEN BETTER MODEL AGREEMENT WE NOW
HAVE HIGHER CONFIDENCE ON COOLER WEATHER ON FRIDAY BEHIND THE FRONT
WHICH SHOULD PERSIST INTO SATURDAY. TEMPERATURES RETURN TO NEAR
NORMAL LEVELS SUNDAY INTO THE BEGINNING OF NEXT WEEK AS UPPER FLOW
PATTERN AMPLIFIES FURTHER. THE VERY PRONOUNCED WAVE IN THE GFS MODEL
EMBEDDED WITHIN THE NORTH-NORTHWESTERLY FLOW BETWEEN BUILDING RIDGE
IN THE WEST AND DEEPENING TROUGH IN THE EAST THIS WEEKEND IS FURTHER
EAST AND NOT QUITE AS PRONOUNCED. THIS IS MORE IN LINE WITH OTHER
MEDIUM RANGE GUIDANCE AND WAS ENOUGH FOR US TO KEEP THE LATTER
PORTION OF THE EXTENDED DRY FOR NOW.
BRB
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 62 82 60 87 61 / 20 5 5 20 20
BEAVER OK 63 83 61 91 62 / 10 5 0 20 40
BOISE CITY OK 58 82 59 89 60 / 10 5 5 30 30
BORGER TX 63 85 63 90 64 / 20 5 5 20 40
BOYS RANCH TX 62 84 60 89 60 / 20 5 5 20 20
CANYON TX 63 82 59 88 61 / 20 5 5 20 20
CLARENDON TX 63 82 62 88 64 / 20 10 5 10 20
DALHART TX 58 83 59 89 59 / 10 5 5 30 30
GUYMON OK 63 84 61 90 61 / 10 5 0 30 40
HEREFORD TX 63 81 60 87 60 / 20 5 5 20 20
LIPSCOMB TX 63 83 61 89 61 / 20 0 0 20 40
PAMPA TX 62 82 61 87 60 / 20 5 0 10 40
SHAMROCK TX 65 84 62 89 63 / 40 5 0 5 30
WELLINGTON TX 66 85 62 90 65 / 40 5 0 5 20
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
8/17
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
929 PM CDT WED SEP 9 2015
.UPDATE...
00Z NAM BRINGS IN LIGHT SHOWERS NORTH OF A PORT WASHINGTON TO LAKE
MILLS TO DARLINGTON LINE BY 7 AM CDT. LATEST HRRR EXPERIMENTAL IS
SIMILAR...BUT MORE SCATTERED.
&&
.AVIATION/06Z TAFS/...
MID LEVEL CLOUDS WILL INCREASE TONIGHT FROM THE WEST AHEAD OF
UPSTREAM TROUGH/COLD FRONT. LATEST MODEL DATA SUGGESTS PRECIP
MOVES IN DURING THE EARLY MORNING AREAS...ESPECIALLY OVER SOUTH
CENTRAL WISCONSIN. STILL EXPECT VFR CONDITIONS.
THE CHANCE OF SHOWERS WILL CONTINUE THURSDAY WITH VFR CIGS
EXPECTED. MAINLY VFR VSBYS BUT SOME MVFR POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 250 PM CDT WED SEP 9 2015/
TONIGHT - CONFIDENCE...MEDIUM
HIGH PRESSURE WITH VERY DRY AIRMASS LINGERS INTO THIS EVENING.
EXPECTING MID DECK TO INCREASE WITH WAA REGIME SETTING UP AHEAD OF
APPCH SHORTWAVE. 88-D RETURNS SE MN AND NE IA CONTINUE TO SHOW SIGNS
OF EROSION. LATER IN THE NIGHT A SRLY FLOW STARTS WITH SOME INCREASE
IN LOW LEVEL MOISTURE. DECENT MID LEVEL LAPSE RATES WILL BE IN PLACE
ACROSS THE WESTERN CWA WHERE FORCING STARTS TO INCREASE WITH CVA REGION
OF SHORTWAVE AND LOWER LEVEL FORCING WITH NEXT COLD FRONT. MESO MODELS
ARE HOLDING OFF ON BRINGING ANYTHING INTO THE NORTHWEST UNTIL AROUND
MIDNIGHT OR A SMIDGE AFTER. EXPECTING AT LEAST THE SOUTHEAST HALF TO
REMAIN DRY.
THURSDAY - CONFIDENCE...MEDIUM
BROAD MID LEVEL CYCLONIC FLOW IN PLACE WITH A FEW VORT MAXES TO
CONTEND WITH. SURFACE/850 FRONTS WILL BE PASSING THROUGH TO SUSTAIN
SOME LOW LEVEL FORCING. THE 12Z GFS HAS COME IN WITH SOME HEFTY QPF
IN THE AFTERNOON. MEANWHILE THE NAM IS SHOWING SPOTTY PRECIP.
PREFERRED THE COMPROMISE LOOK OF THE 00Z ECMWF AND NOW THE 12Z
RUN HAS COME IN LOOKING LIKE THE PRIOR RUN. SO PREFER THE ECMWF
SUGGESTING SOME PRECIP WITH LEADING CVA AND SURFACE/850 TROUGH
AND THEN POTENTIAL REDEVELOPMENT WITH THE LINGERING CYCLONIC FLOW...
BOTH SURFACE AND ALOFT.
THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE MEDIUM.
THE COLD FRONT SHOULD EXIT FAR SOUTHEAST WI BY 00Z FRIDAY.
MEANWHILE...THE MID LEVEL TROUGH WILL CONTINUE TO DEEPEN ACROSS
THE WESTERN GREAT LAKES AND UPPER MS RIVER VALLEY. ALTHOUGH PRECIP
CHANCES WILL BE LOW THURSDAY NIGHT...CAN/T RULE IT OUT WITH THE
CYCLONIC FLOW AND COLD AIR ALOFT MOVING. THE BEST CHANCE FOR DRY
WEATHER WOULD BE WEST OF MADISON. THE MODELS GENERALLY AGREE ON A
COMPACT SHORT WAVE ROTATING SOUTHEAST ACROSS THE AREA ON FRIDAY.
SHOWER CHANCES SHOULD INCREASE WITH THIS FEATURE FRIDAY
AFTERNOON...ALONG WITH MORE CLOUDS. A CHILLY DAY IS IN STORE WITH
HIGHS ONLY IN THE LOWER TO MID 60S.
SATURDAY AND SUNDAY...FORECAST CONFIDENCE IS HIGH.
THE UPPER LOW WILL CLOSE OFF AND CONTINUE TO ROTATE OFF TO THE
EAST BY SATURDAY WITH UPPER RIDGING AND SURFACE HIGH PRESSURE
TAKING OVER. WE COULD SEE SOME LIGHT SHOWERS LINGER IN THE FAR
EAST FRIDAY EVENING...OTHERWISE THINGS WILL DRY OUT QUICKLY WITH
CLEARING SKIES. ALTHOUGH THE WEEKEND LOOKS DRY WITH A FAIR AMOUNT
OF SUNSHINE...HIGH TEMPS WILL STAY IN THE 60S.
MONDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE IS HIGH.
THE PATTERN WILL TRANSITION TO ZONAL THEN SOUTHWEST FLOW BY
TUESDAY RESULTING IN A STEADY WARMUP FOR NEXT WEEK. SURFACE HIGH
PRESSURE DRIFTS SOUTH AND EAST BY MONDAY WITH A WEAKENING TROUGH
OF LOW PRESSURE TRYING TO PUSH INTO THE AREA MONDAY NIGHT.
BUT...IT LOOKS LIKE THIS TROUGH WILL JUST WASH OUT. WE/LL REMAIN
IN A PERSISTENT MILD SOUTHWEST FLOW HOWEVER. TEMPS BY EARLY NEXT
WEEK WILL BE BACK INTO THE 70S. THERE IS SOME DISAGREEMENT BETWEEN
THE GFS AND THE ECMWF BY MID WEEK WITH RESPECT TO THE STRENGTH OF
ANOTHER TROF THAT MAY MOVE INTO THE AREA. FOR NOW...JUST SLIGHT
CHANCE POPS FOR WEDNESDAY WITH BETTER CHANCES POSSIBLE BY
THURSDAY.
AVIATION/00Z TAFS/...WILL INCREASE MID DECK TONIGHT WITH WAA REGIME
AHEAD OF UPSTREAM SHORTWAVE/COLD FRONT. THESE FEATURES ARRIVE
THURSDAY MORNING AND LATEST GUID SUGGESTS PRECIP MOVES IN QUICKER
LATER TONIGHT INTO THURSDAY MORNING. PER LATEST BUFKIT/MOS/SREF WILL
KEEP CIGS AT VFR LEVELS. EXPECTING AN INITIAL BAND OF SHRA/ISOLD TSRA
TO WORK THROUGH IN THE MORNING AND THEN POTENTIAL FOR REDEVELOPMENT
DURING THE AFTERNOON WITH LINGERING CYCLONIC FLOW...IN THE LOW
LEVELS AND ALOFT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...HENTZ
TONIGHT/THURSDAY AND AVIATION/MARINE...COLLAR
THURSDAY NIGHT THROUGH WEDNESDAY...DAVIS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
911 PM CDT WED SEP 9 2015
.UPDATE...
ISSUED AT 908 PM CDT WED SEP 9 2015
TOUGH LITTLE FORECAST OVERNIGHT WITH MARGINAL INSTABILITY TO THE
WEST MOVING INTO THE AREA..WITH SOME WEAK FORCING. SURFACE LOW
AND FRONT ARE STILL WELL WEST NEAR KABR SOUTH DAKOTA...WITH ABOUT
500-1000 J/KG OF MUCAPE FROM KSUX-KSTC ROUGHLY...AND 250 J/KG HAS
FINALLY SHIFTED INTO THE WESTERNMOST MOST FORECAST AREA. THIS
AXIS REPRESENTS THE STORM ACTIVITY AT 02Z. SO FAR...SHOWER
ACTIVITY HAS DIED AS IT HEADS EAST OUT OF THE MOISTURE AXIS. GOES
WATER VAPOR SHOWING A FEW LITTLE WAVES ACROSS SOUTHERN MN...BUT A
MORE IMPRESSIVE SHORTWAVE TROUGH IN WESTERN SD...BOLTING FOR NERN
IA BY SUNRISE.
THE WESTERN SD WAVE WILL BE THE ONE TO SHIFT THE SURFACE LOW AND
FRONT SEWRD OVERNIGHT AND MOISTURE ALOFT WILL INCREASE ON
ISENTROPIC LIFT ACROSS IA/MN...INTO WI.
OVERALL THE IDEA IS THAT LIFT AND LOW-LEVEL CONVERGENCE AND SOME
850 MB MOISTURE TRANSPORT WILL INCREASE OVERNIGHT AS THE FRONT
MOVES THROUGH AND A BIT OF MUCAPE ARRIVES. A BIT MORE FOCUS
ARRIVES LATER FROM NORTHEAST IA INTO CENTRAL WI AS CONVERGENCE
INCREASES ALONG THE FRONT...AND 850MB MOISTURE TRANSPORT
INCREASES. HAVE INCREASED THE LATE NIGHT RAIN CHANCES FOR THIS
DEVELOPMENT.
BY SUNRISE THE VIGOROUS WESTERN SD TROUGH ARRIVES AND HAVE BUMPED
RAIN CHANCES UP ACROSS SERN MN AND NERN IA MAINLY.
OVERALL LIGHTNING THREAT IS VERY ISOLATED WITH LIMITED CAPE.
&&
.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 208 PM CDT WED SEP 9 2015
BIG PICTURE WATER VAPOR IMAGERY/RAP ANALYSIS SHOWING A CLOSED UPPER
LOW OVER WESTERN ONTARIO WITH A BROAD TROUGH OVER THE
NORTHER/CENTRAL CONUS. AN EMBEDDED MID-LEVEL SHORTWAVE TROUGH WAS
PUSHING INTO MN/DAKOTAS. RADAR MOSAIC SHOWING SCATTERED BAND OF
SHOWERS AND THUNDERSTORMS AHEAD OF THIS WAVE EXTENDING FROM
NORTHWEST WI/EAST CENTRAL MN TO SOUTH CENTRAL MN...MOVING EAST AT 35-
40KT. OTHERWISE...TEMPERATURES AS OF 2 PM RANGED FROM NEAR 70 ACROSS
NORTH CENTRAL WI...TO THE 75-80 DEGREE RANGE ALONG AND SOUTH OF I-90.
FOR THIS EVENING OVERNIGHT...WILL BE WATCHING THE WAVE CONTINUE
MOVING EAST ACROSS OUR AREA. RAP DEPICTING INCREASING 850-700MB
MOISTURE TRANSPORT ALONG WITH INCREASING MUCAPE...HIGHER 500-1000
J/KG SOUTH OF I-90. THEREFORE CARRIED SHRA/TS ALONG AND SOUTH OF I-
90 WITH ISOLATED THUNDER NORTH. MOST MESO MODELS DEPICTING SCATTERED
NATURE TO THIS CONVECTION...SO MAINTAINED 30-50 POPS FOR NOW.
ANOTHER STRONGER MID-LEVEL WAVE/DECENT 500-300MB PV-ADVECTION PUSHES
IN ACROSS THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER
VALLEY BY TOMORROW MORNING AND IS EXPECTED TO REINFORCE
SHOWER/THUNDER CHANCES ACROSS THE AREA. WITH EXPECTED SCATTERED
CONVECTION AND CLOUD COVER...WILL SEE COOLER TEMPERATURES WITH HIGHS
ACROSS NORTH CENTRAL WI ONLY IN THE 65-70 DEGREE RANGE AND LOW-MID
70S SOUTH OF I-90.
LOOKS LIKE SHOWER/ISOLATED THUNDER CHANCES PUSH OUT OF THE AREA BY
LATER THURSDAY EVENING WITH CLEARING SKIES THROUGH THE OVERNIGHT
HOURS. WITH DEEPENING MID/UPPER LEVEL TROUGH OVERHEAD AND RATHER
COLD 850MB TEMPS DROPPING INTO THE 1-5C RANGE...WILL SEE OVERNIGHT
LOWS DIP INTO THE 40S MOST LOCATIONS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 208 PM CDT WED SEP 9 2015
FOR FRIDAY THROUGH SATURDAY NIGHT...
ANOTHER EMBEDDED SHORTWAVE TROUGH COMES DOWN ACROSS THE AREA ON
FRIDAY. STEEP LOW TO MID-LEVEL LAPSE RATES EXPECTED TO GENERATE
QUITE A BIT OF CUMULUS AND SCATTERED SHOWERS...MAINLY ALONG AND EAST
OF THE MISSISSIPPI RIVER. OTHERWISE...A RATHER CHILLY AUTUMN-LIKE
DAY ON TAP AS HIGHS ONLY TOP OFF IN THE UPPER 50S TO THE MIDDLE 60S.
CHILLY DAY FRIDAY AND CLEARING SKIES FRIDAY NIGHT AS SURFACE HIGHS
SETTLES IN WILL SET THE STAGE FOR COLD TEMPERATURES FRIDAY NIGHT
WITH LOWS DIPPING INTO TO THE UPPER 30S/AROUND 40 ACROSS NORTH
CENTRAL WI...TO THE LOWER/MIDDLE 40S ELSEWHERE.
MODELS SHOW THE MID-LEVEL TROUGH PUSHING INTO THE EASTERN GREAT
LAKES/OHIO RIVER VALLEY SATURDAY AS MID-LEVEL RIDGE BUILD INTO OUR
REGION. THIS WILL PROVIDE DRY AND SLIGHTLY WARMER //BUT STILL WELL
BELOW NORMAL// TEMPERATURES IN THE LOW-MID 60S UNDER MOSTLY SUNNY
SKIES.
PLAN ON ANOTHER CLEAR AND COLD SATURDAY NIGHT WITH SURFACE HIGH
OVERHEAD. LOOKS TO BE AN IDEAL RIVER VALLEY/BOG AREA FOG NIGHT WITH
OVERNIGHT LOWS DIPPING INTO THE 40S ONCE AGAIN. DID NOT INCLUDE IN
THE WEATHER GRIDS FOR NOW AS EXACT RIDGE LOCATION COULD CHANGE A
BIT...BUT SOMETHING TO KEEP AN EYE ON NONETHELESS.
FOR SUNDAY THROUGH WEDNESDAY...DAYS 4 TO 7...
GFS AND ECMWF IN AGREEMENT ON A WARMING TREND FOR THIS PERIOD AS LOW
PRESSURE LIFT ACROSS THE NORTHERN PLAINS INTO CANADA. THIS PUTS US
IN WARM SECTOR WITH BROAD-SCALE LIFT ACROSS OUR AREA FOR A CHANCE OF
SHOWERS AND THUNDERSTORMS MAINLY IN THE TUESDAY NIGHT THROUGH
WEDNESDAY TIME FRAME. LOOKS LIKE HIGHS ON SUNDAY IN THE 65-70 DEGREE
RANGE...WARMING BACK INTO THE 70S...OR NEAR SEASONAL NORMALS...BY
WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 706 PM CDT WED SEP 9 2015
THE CHALLENGE FOR THESE TAFS WAS TRYING TO KEEP THEM SIMPLE WITH
MANY WEAK WAVES OF WEATHER AND A COOL FRONT MOVING THROUGH THE
AIRFIELD SPACE. OVERALL..THE AIR MASS OVER THE AIRFIELDS IS PRETTY
DRY BELOW 10KFT...AND THE MOISTURE AXIS RUNS FROM WRN IA INTO
CENTRAL MN CURRENTLY. THIS IS WHERE TSRA ACTION IS LOCATED. THE
MOIST AXIS WILL SHIFT EAST OVERNIGHT AND PROVIDE A BIT MORE
INSTABILITY OVER THE AREA AND A BIT OF LIFT WILL HELP PROVIDE AN
OVERNIGHT SHRA CHANCE. BELIEVE THIS WILL BE LATER IN THE
PERIOD...AND IT IS LIKELY TOO LONG A PERIOD INCLUDED IN THE TAFS.
THINKING IT MAY BE 2 HOURS...BUT DIFFICULTY IN NARROWING A TIME
WINDOW KEPT THE FORECAST A 6 HOUR SHRA WINDOW. A SECOND WEATHER
MAKER WILL ARRIVE AROUND SUNRISE..BUT LOOKS MAINLY TO AFFECT KRST.
THE MORNING SHRA CHANCES MAY NEED TO BE INCREASED.
BOTTOM LINE IS VFR LOOKS TO PREVAIL AS A FRONT MOVES THROUGH THE
AREA. SOME TSRA CHANCES ARE OUT THERE OVERNIGHT BUT FEEL THE
PROBABILITIES ARE TOO LOW TO INCLUDE IN THE FORECAST. THE WORST
CASE...LOWEST PROBABILITY SCENARIO SEEMS TO BE STILL ONLY BE MVFR
CONDITIONS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BAUMGARDT
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
706 PM CDT WED SEP 9 2015
.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 208 PM CDT WED SEP 9 2015
BIG PICTURE WATER VAPOR IMAGERY/RAP ANALYSIS SHOWING A CLOSED UPPER
LOW OVER WESTERN ONTARIO WITH A BROAD TROUGH OVER THE
NORTHER/CENTRAL CONUS. AN EMBEDDED MID-LEVEL SHORTWAVE TROUGH WAS
PUSHING INTO MN/DAKOTAS. RADAR MOSAIC SHOWING SCATTERED BAND OF
SHOWERS AND THUNDERSTORMS AHEAD OF THIS WAVE EXTENDING FROM
NORTHWEST WI/EAST CENTRAL MN TO SOUTH CENTRAL MN...MOVING EAST AT 35-
40KT. OTHERWISE...TEMPERATURES AS OF 2 PM RANGED FROM NEAR 70 ACROSS
NORTH CENTRAL WI...TO THE 75-80 DEGREE RANGE ALONG AND SOUTH OF I-90.
FOR THIS EVENING OVERNIGHT...WILL BE WATCHING THE WAVE CONTINUE
MOVING EAST ACROSS OUR AREA. RAP DEPICTING INCREASING 850-700MB
MOISTURE TRANSPORT ALONG WITH INCREASING MUCAPE...HIGHER 500-1000
J/KG SOUTH OF I-90. THEREFORE CARRIED SHRA/TS ALONG AND SOUTH OF I-
90 WITH ISOLATED THUNDER NORTH. MOST MESO MODELS DEPICTING SCATTERED
NATURE TO THIS CONVECTION...SO MAINTAINED 30-50 POPS FOR NOW.
ANOTHER STRONGER MID-LEVEL WAVE/DECENT 500-300MB PV-ADVECTION PUSHES
IN ACROSS THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER
VALLEY BY TOMORROW MORNING AND IS EXPECTED TO REINFORCE
SHOWER/THUNDER CHANCES ACROSS THE AREA. WITH EXPECTED SCATTERED
CONVECTION AND CLOUD COVER...WILL SEE COOLER TEMPERATURES WITH HIGHS
ACROSS NORTH CENTRAL WI ONLY IN THE 65-70 DEGREE RANGE AND LOW-MID
70S SOUTH OF I-90.
LOOKS LIKE SHOWER/ISOLATED THUNDER CHANCES PUSH OUT OF THE AREA BY
LATER THURSDAY EVENING WITH CLEARING SKIES THROUGH THE OVERNIGHT
HOURS. WITH DEEPENING MID/UPPER LEVEL TROUGH OVERHEAD AND RATHER
COLD 850MB TEMPS DROPPING INTO THE 1-5C RANGE...WILL SEE OVERNIGHT
LOWS DIP INTO THE 40S MOST LOCATIONS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 208 PM CDT WED SEP 9 2015
FOR FRIDAY THROUGH SATURDAY NIGHT...
ANOTHER EMBEDDED SHORTWAVE TROUGH COMES DOWN ACROSS THE AREA ON
FRIDAY. STEEP LOW TO MID-LEVEL LAPSE RATES EXPECTED TO GENERATE
QUITE A BIT OF CUMULUS AND SCATTERED SHOWERS...MAINLY ALONG AND EAST
OF THE MISSISSIPPI RIVER. OTHERWISE...A RATHER CHILLY AUTUMN-LIKE
DAY ON TAP AS HIGHS ONLY TOP OFF IN THE UPPER 50S TO THE MIDDLE 60S.
CHILLY DAY FRIDAY AND CLEARING SKIES FRIDAY NIGHT AS SURFACE HIGHS
SETTLES IN WILL SET THE STAGE FOR COLD TEMPERATURES FRIDAY NIGHT
WITH LOWS DIPPING INTO TO THE UPPER 30S/AROUND 40 ACROSS NORTH
CENTRAL WI...TO THE LOWER/MIDDLE 40S ELSEWHERE.
MODELS SHOW THE MID-LEVEL TROUGH PUSHING INTO THE EASTERN GREAT
LAKES/OHIO RIVER VALLEY SATURDAY AS MID-LEVEL RIDGE BUILD INTO OUR
REGION. THIS WILL PROVIDE DRY AND SLIGHTLY WARMER //BUT STILL WELL
BELOW NORMAL// TEMPERATURES IN THE LOW-MID 60S UNDER MOSTLY SUNNY
SKIES.
PLAN ON ANOTHER CLEAR AND COLD SATURDAY NIGHT WITH SURFACE HIGH
OVERHEAD. LOOKS TO BE AN IDEAL RIVER VALLEY/BOG AREA FOG NIGHT WITH
OVERNIGHT LOWS DIPPING INTO THE 40S ONCE AGAIN. DID NOT INCLUDE IN
THE WEATHER GRIDS FOR NOW AS EXACT RIDGE LOCATION COULD CHANGE A
BIT...BUT SOMETHING TO KEEP AN EYE ON NONETHELESS.
FOR SUNDAY THROUGH WEDNESDAY...DAYS 4 TO 7...
GFS AND ECMWF IN AGREEMENT ON A WARMING TREND FOR THIS PERIOD AS LOW
PRESSURE LIFT ACROSS THE NORTHERN PLAINS INTO CANADA. THIS PUTS US
IN WARM SECTOR WITH BROAD-SCALE LIFT ACROSS OUR AREA FOR A CHANCE OF
SHOWERS AND THUNDERSTORMS MAINLY IN THE TUESDAY NIGHT THROUGH
WEDNESDAY TIME FRAME. LOOKS LIKE HIGHS ON SUNDAY IN THE 65-70 DEGREE
RANGE...WARMING BACK INTO THE 70S...OR NEAR SEASONAL NORMALS...BY
WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 706 PM CDT WED SEP 9 2015
THE CHALLENGE FOR THESE TAFS WAS TRYING TO KEEP THEM SIMPLE WITH
MANY WEAK WAVES OF WEATHER AND A COOL FRONT MOVING THROUGH THE
AIRFIELD SPACE. OVERALL..THE AIR MASS OVER THE AIRFIELDS IS PRETTY
DRY BELOW 10KFT...AND THE MOISTURE AXIS RUNS FROM WRN IA INTO
CENTRAL MN CURRENTLY. THIS IS WHERE TSRA ACTION IS LOCATED. THE
MOIST AXIS WILL SHIFT EAST OVERNIGHT AND PROVIDE A BIT MORE
INSTABILITY OVER THE AREA AND A BIT OF LIFT WILL HELP PROVIDE AN
OVERNIGHT SHRA CHANCE. BELIEVE THIS WILL BE LATER IN THE
PERIOD...AND IT IS LIKELY TOO LONG A PERIOD INCLUDED IN THE TAFS.
THINKING IT MAY BE 2 HOURS...BUT DIFFICULTY IN NARROWING A TIME
WINDOW KEPT THE FORECAST A 6 HOUR SHRA WINDOW. A SECOND WEATHER
MAKER WILL ARRIVE AROUND SUNRISE..BUT LOOKS MAINLY TO AFFECT KRST.
THE MORNING SHRA CHANCES MAY NEED TO BE INCREASED.
BOTTOM LINE IS VFR LOOKS TO PREVAIL AS A FRONT MOVES THROUGH THE
AREA. SOME TSRA CHANCES ARE OUT THERE OVERNIGHT BUT FEEL THE
PROBABILITIES ARE TOO LOW TO INCLUDE IN THE FORECAST. THE WORST
CASE...LOWEST PROBABILITY SCENARIO SEEMS TO BE STILL ONLY BE MVFR
CONDITIONS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1056 AM CDT TUE SEP 8 2015
.UPDATE...
ISSUED AT 1056 AM CDT TUE SEP 8 2015
FLASH FLOOD WATCH HAS BEEN CANCELLED WITH HEAVY RAINFALL PUSHED
OUT OF OUR FORECAST AREA INTO EASTERN WISCONSIN. WILL KEEP A LOW-
END SHOWER/ISOLATED THUNDER CHANCE IN FOR PORTIONS OF NORTHEAST IA
INTO FAR SOUTHWEST WI AS RADAR WAS SHOWING SOME WEAK ECHO
UPSTREAM. OTHERWISE...LOOKS DRY GOING INTO THE AFTERNOON AS
SURFACE HIGH PRESSURE AND DRIER AIR BUILDS IN FROM THE DAKOTAS/MN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CDT TUE SEP 8 2015
MAIN FCST CONCERNS THIS PERIOD...SHRA/TSRA CHANCES THIS MORNING...
TEMPERATURES.
DATA ANALYSIS AT 06Z HAD THE OLD FRONTAL BOUNDARY NEAR THE WI/IL
BORDER TO NEAR KDSM/KOMA. A WEAK LOW WAS LOCATED ON THE FRONT NEAR
KOMA. PER WV IMAGERY...A SHORTWAVE WAS MOVING EAST-NORTHEAST ACROSS
OVER NEB. INCREASING LOWER LEVEL THERMO-DYNAMIC FORCING AND MOISTURE
TRANSPORT AHEAD OF THE SFC-700MB TROUGH AND LIFT AHEAD OF THE
SHORTWAVE PRODUCING INCREASING SHRA/TSRA ACROSS SOUTHWEST MN/
NORTHWEST IA. WSR-88D RAINFALL ESTIMATES OF 1-2 INCHES/HR FROM SOME
OF THE TSRA IN SOUTHWEST MN. ELSEWHERE...IT REMAINED ANOTHER WARM
AND HUMID EARLY SEPT NIGHT ACROSS MUCH OF THE UPPER MIDWEST UNDER
INCREASING CLOUD COVER.
08.00Z MODEL RUNS LOOK TO HAVE INITIALIZED WELL. SOLUTIONS QUITE
SIMILAR...AT LEAST AT 500MB...AS ONE SHORTWAVE PASSES EARLY THIS
MORNING THEN THE MAIN MID LEVEL TROUGH AXIS PASSES TONIGHT. TREND IS
TOWARD A TIGHTER CONSENSUS OF THE EARLIER RUNS THRU TONIGHT. STILL
SOME MESO-SCALE DETAIL DIFFERENCES IMPACTING PRECIP PLACEMENT/TIMING
THIS MORNING BUT THIS NOT UNEXPECTED. EVEN WITH THESE DIFFERENCES...
SHORT-TERM FCST CONFIDENCE IS GOOD THIS CYCLE.
FOR THE SHORT TERM...REGIONAL RADAR COMPOSITE SHOWING THE MORE
NORTHERN OF MODEL SOLUTIONS WITH SHRA/TSRA/QPF LOOKING BETTER EARLY
THIS MORNING. RADAR PRECIP ESTIMATES ALSO SHOWING MODEL SOLUTIONS
WITH HEAVIER QPF ALSO LOOKING BETTER. GIVEN PW VALUES OF UP TO 1.75
INCHES /2.5 STANDARD DEVIATIONS ABOVE NORMAL/ IN THE INFLOW
AIRMASS...TREND FOR STORMS TO BE EFFICIENT/HEAVY RAIN PRODUCERS
SHOULD CONTINUE AS THE FORCING/CONVECTION MOVE EAST ACROSS THE FCST
AREA THIS MORNING. RAISED QPF IN THE FCST GRIDS...BUT NOT ALL AREAS
WILL SEE 1 TO 2 INCHES OF RAIN. HOWEVER...IF THIS RAIN FALLS IN
URBAN AREAS...AREAS HIT BY HEAVY RAINS IN RECENT DAYS...OR TSRA
TRAIN/REPEAT OVER THE SAME AREA...MORE FLOODING ISSUES ARE CERTAINLY
POSSIBLE. AFTER COLLABORATION WITH NEIGHBORS...HAVE ISSUED A FLASH
FLOOD WATCH FOR MUCH OF THE FCST AREA FROM 09Z-15Z /NORTHWEST THIRD/
OR 09Z-18Z /CENTRAL AND SOUTH PARTS/ TODAY. WITH PASSAGE OF THE
SHORTWAVE AND SFC-500MB TROUGH AXIS...FORCING/LIFT AND DEEPER
MOISTURE QUICKLY MOVE EAST OF THE AREA BY LATE THIS MORNING INTO
EARLY THIS AFTERNOON. CARRIED HIGHEST SHRA/TSRA CHANCES IN THE 12-
15Z PERIOD THIS MORNING...TRENDING DOWN AND EASTWARD RATHER QUICKLY
THRU THE LATE MORNING/EARLY AFTERNOON HOURS. SFC-700MB WINDS REMAIN
LIGHT TODAY...WITH LOWER LEVEL MOISTURE/CLOUDS BEHIND THE LOW/TROUGH
AXIS LIKELY SLOW TO CLEAR OUT. HAVE RAISED CLOUD COVER IN GRIDS THRU
MUCH OF TODAY. STRONGER OF THE LOWER LEVEL DRYING/COOLING PUSHES IN
TONIGHT WITH PASSAGE OF THE MAIN MID LEVEL TROUGH AXIS. MODELS
SHOWING PW VALUES DROP TO AROUND 1/2 INCH OVER THE AREA BY 12Z WED.
WITH LOWER LEVEL COLD ADVECTION AND ANTI-CYCLONIC FLOW...SKIES
EXPECTED TO BECOME CLEAR/MOSTLY CLEAR BY LATE EVENING. LOWER LEVEL
COLD ADVECTION...LIGHT BOUNDARY LAYER WINDS AND THE MOSTLY CLEAR
SKIES...LOWS TONIGHT TRENDING TO BE MUCH CLOSER TO NORMAL THAN THOSE
OF THE PAST WEEK. STAYED WITH A BLEND OF THE GUIDANCE HIGHS/LOWS FOR
TODAY/TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE SEP 8 2015
FOR WEDNESDAY THRU THURSDAY NIGHT...
MAIN FCST CONCERNS THIS PERIOD...SHRA/TSRA CHANCES LATE WED NIGHT
INTO THU NIGHT...TEMPERATURES.
08.00Z MODEL RUNS IN GOOD AND IMPROVING AGREEMENT THIS PERIOD AS
HGTS FALL/MID LEVEL TROUGHING DEEPENS OVER THE NORTH CENTRAL CONUS.
GENERALLY TREND IS DEEPER/STRONGER WITH THE TROUGH AND SHORTWAVE
ENERGY IN IT OVER THE REGION BY THU/THU NIGHT. GIVEN THE TIGHTER
MODEL CONSENSUS...FCST CONFIDENCE THIS PERIOD IS GOOD THIS CYCLE.
QUIET...DRY...MOSTLY SUNNY...SEASONABLE DAY ON WED AS CANADIAN HIGH
PRESSURE AND A DRY LOWER LEVEL AIRMASS SLIDE ACROSS THE UPPER
MIDWEST. THIS DOES NOT LAST LONG WITH THE TROUGH ALOFT DEEPENING AND
APPROACH OF THE LEAD SHORTWAVE ENERGY. NEXT SFC TROUGH/FRONT IS
ALREADY INTO NORTHERN WI TO SOUTHWEST MN BY 12Z THU. CONSISTENT
SIGNAL FOR LOWER LEVEL MOISTURE TO QUICKLY RETURN NORTHWARD AHEAD OF
THE SFC-700MB TROUGH...ALONG WITH AN INCREASE OF LOWER LEVEL
CONVERGENCE/ISENTROPIC LIFT. SOME WEAK MUCAPE EVEN INDICATED AHEAD
OF THE TROUGH BY 12Z THU. SMALL SHRA/ISOLATED TSRA CHANCE OVER THE
NORTHWEST HALF OF THE FCST AREA LATER WED NIGHT REASONABLE FOR NOW.
MOISTURE/CAPE AHEAD OF THE LOWER LEVEL TROUGH CONTINUE TO INCREASE
ON THU. SOME TIMING DIFFERENCES WITH PROGRESSIVENESS OF THE SFC-
700MB TROUGH/FRONT BY 00Z FRI. HOWEVER TIGHTENING CONSENSUS FOR ENOUGH
LIFT/MOISTURE FOR SOME SHRA/TSRA TO ACCOMPANY IT AS IT MOVES ACROSS
THE FCST AREA THU/THU NIGHT. STAYED WITH THE CONSENSUS SHRA/TSRA
CHANCES FOR THU/THU NIGHT FOR NOW...PENDING BETTER TIMING AGREEMENT
AMONG THE MODELS. STRONGER SHOT OF LOW LEVEL COLD ADVECTION FOLLOWS
IN THE WAKE OF THE TROUGH/FRONT FOR THU NIGHT...WITH THU NIGHT LOWS
TRENDING BELOW NORMAL. USED A BLEND OF THE GUIDANCE HIGHS/LOWS FOR
WED THRU THU NIGHT.
FOR FRIDAY THRU MONDAY...DAYS 4 TO 7...
MAIN FCST CONCERNS THIS PERIOD...COOLER TEMPERATURES...SMALL SHRA
CHANCES BY SUN NIGHT/MON.
MEDIUM RANGE MODEL RUNS OF 08.00Z SHOW IMPROVING AGREEMENT FOR
TROUGHING TO DEEPEN OVER THE GREAT LAKES FRI THRU SAT...WITH DEEP
NORTHERLY FLOW OVER THE REGION BY 00Z SUN. REASONABLE CONSENSUS FOR
THE TROUGHING TO DIG INTO THE EASTERN CONUS SAT NIGHT/SUN...WITH
SHORTWAVE RIDGING/RISING HGTS BUILDING INTO THE UPPER MIDWEST BEHIND
IT. BY SUN NIGHT/MON SOME CONSISTENCY FOR HGTS TO FALL AGAIN AS A
STRONGER SHORTWAVE TRACKS EAST ALONG THE US/CAN BORDER. WITH THE
BETTER MODEL CONSENSUS...THE LONG TERM FCST CONFIDENCE IS ABOVE
AVERAGE THIS CYCLE.
THIS PERIOD STARTS OUT WITH CAN HIGH PRESSURE BUILDING INTO THE
REGION. DEEP NORTHWEST TO NORTH FLOW CONTINUES TO SPREAD LOW LEVEL
COLD ADVECTION SPREADING ACROSS THE AREA WITH 850MB TEMPS BY 00Z SAT
1 TO 2 STANDARD DEVIATIONS BELOW NORMAL. FRI THRU SAT CONTINUES TO
SHAPE UP AS A DRY...COOL PERIOD WITH TEMPS SOME 5F TO 10F BELOW
NORMAL. SFC-850MB HIGH WOULD MOVE SOUTH OF THE AREA BY SUNDAY...WITH
SOME LOW LEVEL WARM ADVECTION RETURNING. TROUGHING/SHORTWAVE MOVING
ACROSS SOUTHERN CAN SUN NIGHT/MON WOULD DRAG A FRONTAL BOUNDARY INTO
THE REGION...WITH AN INCREASE OF MOISTURE/CONVERGENCE/LIFT AND SOME
MUCAPE AHEAD OF IT. PLENTY OF TIMING DIFFERENCES BY MON...BUT A
SMALL SHRA/TSRA CHANCE ACROSS MAINLY THE NORTH END OF THE FCST AREA
BY LATER SUN NIGHT/MON REASONABLE AT THIS POINT. MODEL/ENSEMBLE
CONSENSUS OF HIGHS/LOWS FOR FRI THRU MON SEEMS TO HAVE THEM WELL
TREND AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1143 PM CDT MON SEP 7 2015
WATCHING THE CONVECTION SLOWLY FILL IN ACROSS NORTHWEST IOWA AND
SOUTHWEST MINNESOTA AHEAD OF THE SHORT WAVE TROUGH COMING OUT OF
NEBRASKA. SEVERAL OF THE HI-RES MESO MODELS NOW SUGGEST THIS AREA
WILL CONTINUE TO EXPAND AND SWING THOUGH THE INTERSTATE 90 CORRIDOR
LATE TONIGHT INTO EARLY TUESDAY MORNING. HAVE THUS TRENDED THE
FORECAST TOWARD THESE SOLUTIONS OF BRINGING SOME LEADING SHOWERS
WITH A VCSH BEFORE THE MAIN BAND OF SHOWERS AND STORMS COMES IN. THE
08.03Z RAP FORECAST SOUNDINGS SUGGEST THE POTENTIAL FOR IFR
CONDITIONS AS THIS COMPLEX OF STORMS MOVES THROUGH AND IF IT EVOLVES
AS THE MESO MODELS SUGGEST...THIS SEEMS ENTIRELY REALISTIC. THE
COMPLEX SHOULD MOVE OUT FAIRLY QUICKLY TUESDAY MORNING BUT EXPECTING
THE IFR CEILINGS TO REMAIN UNTIL LATE AFTERNOON UNTIL SOME DRIER AIR
STARTS TO WORK IN FROM THE NORTHWEST TO ALLOW THE CONDITIONS TO GO
UP TO VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...DAS
SHORT TERM...RRS
LONG TERM....RRS
AVIATION.....04
HYDROLOGY....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
333 AM CDT TUE SEP 8 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CDT TUE SEP 8 2015
MAIN FCST CONCERNS THIS PERIOD...SHRA/TSRA CHANCES THIS MORNING...
TEMPERATURES.
DATA ANALYSIS AT 06Z HAD THE OLD FRONTAL BOUNDARY NEAR THE WI/IL
BORDER TO NEAR KDSM/KOMA. A WEAK LOW WAS LOCATED ON THE FRONT NEAR
KOMA. PER WV IMAGERY...A SHORTWAVE WAS MOVING EAST-NORTHEAST ACROSS
OVER NEB. INCREASING LOWER LEVEL THERMO-DYNAMIC FORCING AND MOISTURE
TRANSPORT AHEAD OF THE SFC-700MB TROUGH AND LIFT AHEAD OF THE
SHORTWAVE PRODUCING INCREASING SHRA/TSRA ACROSS SOUTHWEST MN/
NORTHWEST IA. WSR-88D RAINFALL ESTIMATES OF 1-2 INCHES/HR FROM SOME
OF THE TSRA IN SOUTHWEST MN. ELSEWHERE...IT REMAINED ANOTHER WARM
AND HUMID EARLY SEPT NIGHT ACROSS MUCH OF THE UPPER MIDWEST UNDER
INCREASING CLOUD COVER.
08.00Z MODEL RUNS LOOK TO HAVE INITIALIZED WELL. SOLUTIONS QUITE
SIMILAR...AT LEAST AT 500MB...AS ONE SHORTWAVE PASSES EARLY THIS
MORNING THEN THE MAIN MID LEVEL TROUGH AXIS PASSES TONIGHT. TREND IS
TOWARD A TIGHTER CONSENSUS OF THE EARLIER RUNS THRU TONIGHT. STILL
SOME MESO-SCALE DETAIL DIFFERENCES IMPACTING PRECIP PLACEMENT/TIMING
THIS MORNING BUT THIS NOT UNEXPECTED. EVEN WITH THESE DIFFERENCES...
SHORT-TERM FCST CONFIDENCE IS GOOD THIS CYCLE.
FOR THE SHORT TERM...REGIONAL RADAR COMPOSITE SHOWING THE MORE
NORTHERN OF MODEL SOLUTIONS WITH SHRA/TSRA/QPF LOOKING BETTER EARLY
THIS MORNING. RADAR PRECIP ESTIMATES ALSO SHOWING MODEL SOLUTIONS
WITH HEAVIER QPF ALSO LOOKING BETTER. GIVEN PW VALUES OF UP TO 1.75
INCHES /2.5 STANDARD DEVIATIONS ABOVE NORMAL/ IN THE INFLOW
AIRMASS...TREND FOR STORMS TO BE EFFICIENT/HEAVY RAIN PRODUCERS
SHOULD CONTINUE AS THE FORCING/CONVECTION MOVE EAST ACROSS THE FCST
AREA THIS MORNING. RAISED QPF IN THE FCST GRIDS...BUT NOT ALL AREAS
WILL SEE 1 TO 2 INCHES OF RAIN. HOWEVER...IF THIS RAIN FALLS IN
URBAN AREAS...AREAS HIT BY HEAVY RAINS IN RECENT DAYS...OR TSRA
TRAIN/REPEAT OVER THE SAME AREA...MORE FLOODING ISSUES ARE CERTAINLY
POSSIBLE. AFTER COLLABORATION WITH NEIGHBORS...HAVE ISSUED A FLASH
FLOOD WATCH FOR MUCH OF THE FCST AREA FROM 09Z-15Z /NORTHWEST THIRD/
OR 09Z-18Z /CENTRAL AND SOUTH PARTS/ TODAY. WITH PASSAGE OF THE
SHORTWAVE AND SFC-500MB TROUGH AXIS...FORCING/LIFT AND DEEPER
MOISTURE QUICKLY MOVE EAST OF THE AREA BY LATE THIS MORNING INTO
EARLY THIS AFTERNOON. CARRIED HIGHEST SHRA/TSRA CHANCES IN THE 12-
15Z PERIOD THIS MORNING...TRENDING DOWN AND EASTWARD RATHER QUICKLY
THRU THE LATE MORNING/EARLY AFTERNOON HOURS. SFC-700MB WINDS REMAIN
LIGHT TODAY...WITH LOWER LEVEL MOISTURE/CLOUDS BEHIND THE LOW/TROUGH
AXIS LIKELY SLOW TO CLEAR OUT. HAVE RAISED CLOUD COVER IN GRIDS THRU
MUCH OF TODAY. STRONGER OF THE LOWER LEVEL DRYING/COOLING PUSHES IN
TONIGHT WITH PASSAGE OF THE MAIN MID LEVEL TROUGH AXIS. MODELS
SHOWING PW VALUES DROP TO AROUND 1/2 INCH OVER THE AREA BY 12Z WED.
WITH LOWER LEVEL COLD ADVECTION AND ANTI-CYCLONIC FLOW...SKIES
EXPECTED TO BECOME CLEAR/MOSTLY CLEAR BY LATE EVENING. LOWER LEVEL
COLD ADVECTION...LIGHT BOUNDARY LAYER WINDS AND THE MOSTLY CLEAR
SKIES...LOWS TONIGHT TRENDING TO BE MUCH CLOSER TO NORMAL THAN THOSE
OF THE PAST WEEK. STAYED WITH A BLEND OF THE GUIDANCE HIGHS/LOWS FOR
TODAY/TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE SEP 8 2015
FOR WEDNESDAY THRU THURSDAY NIGHT...
MAIN FCST CONCERNS THIS PERIOD...SHRA/TSRA CHANCES LATE WED NIGHT
INTO THU NIGHT...TEMPERATURES.
08.00Z MODEL RUNS IN GOOD AND IMPROVING AGREEMENT THIS PERIOD AS
HGTS FALL/MID LEVEL TROUGHING DEEPENS OVER THE NORTH CENTRAL CONUS.
GENERALLY TREND IS DEEPER/STRONGER WITH THE TROUGH AND SHORTWAVE
ENERGY IN IT OVER THE REGION BY THU/THU NIGHT. GIVEN THE TIGHTER
MODEL CONSENSUS...FCST CONFIDENCE THIS PERIOD IS GOOD THIS CYCLE.
QUIET...DRY...MOSTLY SUNNY...SEASONABLE DAY ON WED AS CANADIAN HIGH
PRESSURE AND A DRY LOWER LEVEL AIRMASS SLIDE ACROSS THE UPPER
MIDWEST. THIS DOES NOT LAST LONG WITH THE TROUGH ALOFT DEEPENING AND
APPROACH OF THE LEAD SHORTWAVE ENERGY. NEXT SFC TROUGH/FRONT IS
ALREADY INTO NORTHERN WI TO SOUTHWEST MN BY 12Z THU. CONSISTENT
SIGNAL FOR LOWER LEVEL MOISTURE TO QUICKLY RETURN NORTHWARD AHEAD OF
THE SFC-700MB TROUGH...ALONG WITH AN INCREASE OF LOWER LEVEL
CONVERGENCE/ISENTROPIC LIFT. SOME WEAK MUCAPE EVEN INDICATED AHEAD
OF THE TROUGH BY 12Z THU. SMALL SHRA/ISOLATED TSRA CHANCE OVER THE
NORTHWEST HALF OF THE FCST AREA LATER WED NIGHT REASONABLE FOR NOW.
MOISTURE/CAPE AHEAD OF THE LOWER LEVEL TROUGH CONTINUE TO INCREASE
ON THU. SOME TIMING DIFFERENCES WITH PROGRESSIVENESS OF THE SFC-
700MB TROUGH/FRONT BY 00Z FRI. HOWEVER TIGHTENING CONSENSUS FOR ENOUGH
LIFT/MOISTURE FOR SOME SHRA/TSRA TO ACCOMPANY IT AS IT MOVES ACROSS
THE FCST AREA THU/THU NIGHT. STAYED WITH THE CONSENSUS SHRA/TSRA
CHANCES FOR THU/THU NIGHT FOR NOW...PENDING BETTER TIMING AGREEMENT
AMONG THE MODELS. STRONGER SHOT OF LOW LEVEL COLD ADVECTION FOLLOWS
IN THE WAKE OF THE TROUGH/FRONT FOR THU NIGHT...WITH THU NIGHT LOWS
TRENDING BELOW NORMAL. USED A BLEND OF THE GUIDANCE HIGHS/LOWS FOR
WED THRU THU NIGHT.
FOR FRIDAY THRU MONDAY...DAYS 4 TO 7...
MAIN FCST CONCERNS THIS PERIOD...COOLER TEMPERATURES...SMALL SHRA
CHANCES BY SUN NIGHT/MON.
MEDIUM RANGE MODEL RUNS OF 08.00Z SHOW IMPROVING AGREEMENT FOR
TROUGHING TO DEEPEN OVER THE GREAT LAKES FRI THRU SAT...WITH DEEP
NORTHERLY FLOW OVER THE REGION BY 00Z SUN. REASONABLE CONSENSUS FOR
THE TROUGHING TO DIG INTO THE EASTERN CONUS SAT NIGHT/SUN...WITH
SHORTWAVE RIDGING/RISING HGTS BUILDING INTO THE UPPER MIDWEST BEHIND
IT. BY SUN NIGHT/MON SOME CONSISTENCY FOR HGTS TO FALL AGAIN AS A
STRONGER SHORTWAVE TRACKS EAST ALONG THE US/CAN BORDER. WITH THE
BETTER MODEL CONSENSUS...THE LONG TERM FCST CONFIDENCE IS ABOVE
AVERAGE THIS CYCLE.
THIS PERIOD STARTS OUT WITH CAN HIGH PRESSURE BUILDING INTO THE
REGION. DEEP NORTHWEST TO NORTH FLOW CONTINUES TO SPREAD LOW LEVEL
COLD ADVECTION SPREADING ACROSS THE AREA WITH 850MB TEMPS BY 00Z SAT
1 TO 2 STANDARD DEVIATIONS BELOW NORMAL. FRI THRU SAT CONTINUES TO
SHAPE UP AS A DRY...COOL PERIOD WITH TEMPS SOME 5F TO 10F BELOW
NORMAL. SFC-850MB HIGH WOULD MOVE SOUTH OF THE AREA BY SUNDAY...WITH
SOME LOW LEVEL WARM ADVECTION RETURNING. TROUGHING/SHORTWAVE MOVING
ACROSS SOUTHERN CAN SUN NIGHT/MON WOULD DRAG A FRONTAL BOUNDARY INTO
THE REGION...WITH AN INCREASE OF MOISTURE/CONVERGENCE/LIFT AND SOME
MUCAPE AHEAD OF IT. PLENTY OF TIMING DIFFERENCES BY MON...BUT A
SMALL SHRA/TSRA CHANCE ACROSS MAINLY THE NORTH END OF THE FCST AREA
BY LATER SUN NIGHT/MON REASONABLE AT THIS POINT. MODEL/ENSEMBLE
CONSENSUS OF HIGHS/LOWS FOR FRI THRU MON SEEMS TO HAVE THEM WELL
TREND AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1143 PM CDT MON SEP 7 2015
WATCHING THE CONVECTION SLOWLY FILL IN ACROSS NORTHWEST IOWA AND
SOUTHWEST MINNESOTA AHEAD OF THE SHORT WAVE TROUGH COMING OUT OF
NEBRASKA. SEVERAL OF THE HI-RES MESO MODELS NOW SUGGEST THIS AREA
WILL CONTINUE TO EXPAND AND SWING THOUGH THE INTERSTATE 90 CORRIDOR
LATE TONIGHT INTO EARLY TUESDAY MORNING. HAVE THUS TRENDED THE
FORECAST TOWARD THESE SOLUTIONS OF BRINGING SOME LEADING SHOWERS
WITH A VCSH BEFORE THE MAIN BAND OF SHOWERS AND STORMS COMES IN. THE
08.03Z RAP FORECAST SOUNDINGS SUGGEST THE POTENTIAL FOR IFR
CONDITIONS AS THIS COMPLEX OF STORMS MOVES THROUGH AND IF IT EVOLVES
AS THE MESO MODELS SUGGEST...THIS SEEMS ENTIRELY REALISTIC. THE
COMPLEX SHOULD MOVE OUT FAIRLY QUICKLY TUESDAY MORNING BUT EXPECTING
THE IFR CEILINGS TO REMAIN UNTIL LATE AFTERNOON UNTIL SOME DRIER AIR
STARTS TO WORK IN FROM THE NORTHWEST TO ALLOW THE CONDITIONS TO GO
UP TO VFR.
&&
.HYDROLOGY...
ISSUED AT 333 AM CDT TUE SEP 8 2015
HAVE ISSUED A FLASH FLOOD WATCH FOR MUCH OF THE FCST AREA FROM 09Z
THIS MORNING TO 15Z /NORTHWEST 1/3/ TO 18Z /ELSEWHERE/. SHRA/TSRA
JUST WEST OF THE FCST AREA HAVE A HISTORY OF BEING EFFICIENT RAIN
MAKERS WITH UP TO 1 TO 2 INCHES/HR. ANTECEDENT CONDITIONS ACROSS
PORTIONS OF THE FCST AREA NOT THE MOST FAVORABLE FOR FLASH
FLOODING BUT WITH SOME POTENTIAL FOR STORMS TO TRAIN/REPEAT THIS
MORNING...CANNOT RULE OUT POSSIBILITY OF LOCAL 3+ INCH RAIN
AMOUNTS SOMEWHERE WITHIN THE FCST AREA. IF 1 TO 2 INCHES/HR WOULD
OCCUR OVER AN URBAN AREA...RUNOFF/FLOODED STREETS WOULD DEVELOP
RATHER QUICKLY AND BECOME A PROBLEM...POTENTIALLY DURING THE
MORNING COMMUTE. SEE SHORT-TERM DISCUSSION FOR A BIT MORE ON THE
HEAVY RAIN/FLASH FLOOD THREAT THIS MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FLASH FLOOD WATCH UNTIL 1 PM CDT THIS AFTERNOON FOR WIZ029-033-
034-041-042-053>055-061.
FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR WIZ032.
MN...FLASH FLOOD WATCH UNTIL 1 PM CDT THIS AFTERNOON FOR MNZ088-095-
096.
FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR MNZ079-086-
087-094.
IA...FLASH FLOOD WATCH UNTIL 1 PM CDT THIS AFTERNOON FOR IAZ009>011-
018-019-029-030.
FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR IAZ008.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION.....04
HYDROLOGY....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1143 PM CDT MON SEP 7 2015
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 305 PM CDT MON SEP 7 2015
A WARM FRONT WAS HUNG UP OVER SOUTHERN IA...STRETCHING INTO SOUTHERN
WI. THE LOW LEVEL JET WILL INCREASE THIS EVENING...PUSHING INTO AND
ACROSS THE BOUNDARY. A LOFT...THE RIGHT ENTRANCE REGION OF A 300 MB
JET STREAK WILL ENHANCE THE AVAILABLE LIFT. HIGH PWS OF 2 INCHES...A
+2 ANOMALY VIA NAEFS...WITH WARM CLOUD DEPTHS OF 4 KFT...AROUND AND
NORTH OF THE FRONT. A RIPPLE IN THE UPPER LEVEL FLOW IS ALSO PROGGED
TO SLIDE FROM THE SOUTHERN PLAINS TO ACROSS THIS FRONT OVERNIGHT.
ALL THIS SHOULD RESULT IN A BLOSSOMING AREA OF SHOWERS AND
THUNDERSTORMS...CAPABLE OF HEAVY RAIN. MESO MODELS TRENDS FAVOR
KEEPING THE BULK OF THE PCPN THREAT ALONG AND SOUTH OF I-90...WITH
THE HEAVY RAIN MOSTLY CONFINED TO IOWA.
MODEL TRENDS HAVE BEEN SLOWING THIS SYSTEM DOWN A BIT OVER THE PAST
FEW DAYS...AND EXPECT PCPN TO LINGER ACROSS THE EAST TUE MORNING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 305 PM CDT MON SEP 7 2015
DOWNTURN IN THE TEMPERATURES AS LARGE SCALE PATTERN SHIFT FROM
RIDGING TO TROUGH/NORTHWEST FLOW CONTINUES. 850 MB TEMPS ARE
EXPECTED TO DROP FROM 18 C AT 00Z TUE TO 5 C BY 00Z SAT. NAEFS 850
MB TEMP ANOMALIES HOVER NEAR -1 THU THROUGH THE WEEKEND. A DAY OR
TWO WITH HIGHS ONLY IN THE 60S AND LOWS IN THE 40S ARE EXPECTED -
WITH FRI/SAT MORNING LOOKING LIKE THE COOLEST PERIOD.
VARIOUS RIPPLES WILL MOVE ALONG THE NORTHWEST FLOW...WITH PREVIOUS
MODEL RUNS TAKING THEM MOSTLY NORTH/SOUTH OF THE LOCAL AREA...OR
WEAKENING THEM AS THEY MOVED IN. LAST RUN OR TWO THEY HAVE CHANGED
THEIR TUNE. THE GFS/GEM/ECMWF ALL SLIDE AN UPPER LEVEL SHORTWAVE
ACROSS THE UPPER MISSISSIPPI RIVER VALLEY THU/FRI. THAT AND A
RELATED SFC BOUNDARY COULD SPARK SHOWERS/STORMS AS IT MOVES THROUGH.
NOT MUCH INSTABILITY...SO IF PCPN DEVELOPS...MORE ON THE SHOWER THAN
THUNDERSTORM SIDE. SHOWERS COULD LINGER/REDEVELOP ON FRIDAY IN WRAP
AROUND REGION OF THE SFC LOW/FAVORABLE LOW LEVEL LAPSES...MORE SO
ACROSS NORTHERN WI.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1143 PM CDT MON SEP 7 2015
WATCHING THE CONVECTION SLOWLY FILL IN ACROSS NORTHWEST IOWA AND
SOUTHWEST MINNESOTA AHEAD OF THE SHORT WAVE TROUGH COMING OUT OF
NEBRASKA. SEVERAL OF THE HI-RES MESO MODELS NOW SUGGEST THIS AREA
WILL CONTINUE TO EXPAND AND SWING THOUGH THE INTERSTATE 90
CORRIDOR LATE TONIGHT INTO EARLY TUESDAY MORNING. HAVE THUS
TRENDED THE FORECAST TOWARD THESE SOLUTIONS OF BRINGING SOME
LEADING SHOWERS WITH A VCSH BEFORE THE MAIN BAND OF SHOWERS AND
STORMS COMES IN. THE 08.03Z RAP FORECAST SOUNDINGS SUGGEST THE
POTENTIAL FOR IFR CONDITIONS AS THIS COMPLEX OF STORMS MOVES
THROUGH AND IF IT EVOLVES AS THE MESO MODELS SUGGEST...THIS SEEMS
ENTIRELY REALISTIC. THE COMPLEX SHOULD MOVE OUT FAIRLY QUICKLY
TUESDAY MORNING BUT EXPECTING THE IFR CEILINGS TO REMAIN UNTIL
LATE AFTERNOON UNTIL SOME DRIER AIR STARTS TO WORK IN FROM THE
NORTHWEST TO ALLOW THE CONDITIONS TO GO UP TO VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
355 AM EDT THU SEP 10 2015
.DISCUSSION...
TODAY-TONIGHT...
ATLC RIDGE AXIS CENTERED OVER THE NRN BAHAMAS AND EXTENDING INTO THE
WRN GOMEX WILL INTERACT WITH A DEEP AND SLOW MOVING FRONTAL TROF
PRESSING INTO THE MID/DEEP SOUTH TO GENERATE A SWRLY BREEZE THRU THE
COLUMN ACRS CENTRAL FL. RAP ANALYSIS OF THE MOISTURE FIELDS SHOWS AN
AIRMASS SLIGHTLY ON THE DRY SIDE...MEAN RH GENERALLY AOB 70PCT THRU
THE H100-H70 LYR AND BLO 60PCT THRU THE H85-H50 LYR.
EVENING SOUNDINGS REFLECT THIS WITH PWAT VALUES BTWN 1.8"-2.0"...BUT
WITH A SUBSTANTIAL AMOUNT OF MID LVL DRY AIR: AVG DEWPOINT
DEPRESSIONS THRU THE H85-H50 LYR BTWN 7-10C DEG...WITH READINGS OVER
10C NOSING THEIR WAY UP THE I-4 CORRIDOR. MUCH OF THE MOISTURE IS
ASSOCIATED WITH A PLUME OF UPR LVL DEBRIS CLOUDS FROM CONVECTIVE
ACTIVITY OFF THE COAST OF GUATEMALA AND THE YUCATAN PENINSULA.
H85-H30 VORTICITY AND H30-H20 DIVERGENCE FIELDS REMAIN QUITE WEAK
WITH LITTLE CHANGE ANTICIPATED AS THE STRENGTH...DEPTH...AND
POSITION OF THE RIDGE WILL DEFLECT ANY ENERGY RIPPLES FROM ADVECTING
INTO THE CENTRAL PENINSULA. MID LVL TEMP PROFILE A BIT MORE UNSTABLE
THAN WED: A WEAK H70 THERMAL RIDGE REMAINS DRAPED OVER CENTRAL FL
WITH READINGS ARND 10C...H50 TEMPS ARND -6C BUT WITH POTENTIAL TO
DROP TO ARND -7C AS THE FRONTAL TROF PRESSES INTO THE THE NW FLANK
OF THE RIDGE AND SHUNTS COOLER AIR IN FROM THE NE GOMEX. INDEED...
GFS INDICATING LAPSE RATES IN THE H70-H50 LYR STEEPENING TO BTWN
6.5-7.0C/KM BY DAYBREAK.
UPR LVL DEBRIS CLOUDS WILL COMBINE WITH THE DRIER MID LVL AIR AND
WEAK DYNAMIC SUPPORT TO KEEP PRECIP CHANCES BLO 50PCT. BRISK SW FLOW
ACRS THE NRN CWA AS THE FRONTAL TROF BEGINS TO INTERACT WITH THE
ATLC RIDGE...SEA BREEZE FORMATION NOT EXPECTED FROM THE CAPE
NWD...WILL GO WITH LOWER POPS ALONG AND N OF THE I-4 CORRIDOR.
WEAKER FLOW S OF THE CAPE WILL ALLOW THE SEABREEZE TO FORM BUT WILL
KEEP IT SUPPRESSED ALONG THE I-95 CORRIDOR...WILL GO WITH HIGHER
POPS THERE...MARTIN/ST. LUCIE COUNTIES SLIGHTLY LOW TO ACCOUNT FOR
THE SHADOW EFFECT OF LAKE OKEECHOBEE. WITH LIMITED DYNAMIC
SUPPORT...PRECIP SHOULD BURN OUT SHORTLY AFT SUNSET...WILL KEEP 20
POPS ALONG THE COAST AND ARND LAKE OKEECHOBEE THRU 02Z TO ACCOUNT
FOR BLOW BACK PRECIP IN THE SW FLOW REGIME.
WARM S/SW BREEZE WILL PUSH MAX TEMPS INTO THE L/M90S...WHILE SFC
DEWPOINTS IN THE M70S SUGGEST OVERNIGHT MIN TEMPS ON THE SAME ORDER.
FRI/FRI NIGHT...
TROUGHING OVER THE OHIO VALLEY/EASTERN US BEGINS ITS RAPID
AMPLIFICATION DURING THE DAY...SHUNTING WHATEVER MID/UPPER LEVEL
RIDGING THAT WAS OVER THE STATE TO OUR SOUTH AND EAST. SOUTHWEST
FLOW THROUGH THE COLUMN INCREASES DURING THE DAY...EVEN AT THE
SURFACE...WHERE IT MAY PRECLUDE THE DEVELOPMENT OF THE EAST COAST
SEA BREEZE...ESPECIALLY NORTH OF THE CAPE. COOLER TEMPERATURES
ALOFT...AS LOW AS -8.5C AT 500MB...SHOULD HELP STEEPEN LAPSE RATES
AND PROVIDE A LITTLE MORE VIGOR TO AFTERNOON STORM DEVELOPMENT.
AFTERNOON CONVECTION WILL FOCUS ON THE EASTERN SIDE OF THE PENINSULA
WITH 50-60 POPS IN ORDER.
SAT-SUN...
MID/UPPER LEVEL TROUGH WILL REACH ITS MAXIMUM AMPLITUDE BY LATE
SATURDAY BEFORE CUTTING OFF EARLY SUNDAY. THE TROUGH IS EXPECTED TO
DEEPEN INTO THE NORTHERN GULF...KEEPING THE AREA UNDER DEEP CYCLONIC
FLOW WHILE PIECES OF ENERGY PASS OVERHEAD IN BRISK SOUTHWEST FLOW
ALOFT. MEANWHILE...A SURFACE BOUNDARY WILL APPROACH THE NORTHERN
PART OF THE STATE BEFORE WASHING OUT OVER CENTRAL FLORIDA EARLY
MONDAY. DESPITE AMPLE HIGH LEVEL CLOUDS STREAMING IN FROM THE
GULF...THIS RATHER ANOMALOUS SYNOPTIC SETUP SPELLS OUT HIGHER THAN
NORMAL RAIN CHANCES THIS WEEKEND.
MON-WED...
UPPER TROUGH OVER THE EAST QUICKLY LIFTS WHILE SURFACE HIGH PRESSURE
PUSHES OFF THE MID ATLANTIC. WHATEVER IS LEFT OF THE SURFACE FRONTAL
BOUNDARY WILL WASH OUT OVER THE AREA...PUTTING CENTRAL FLORIDA IN
DEEP EASTERLY FLOW FOR THE EARLY PART OF NEXT WEEK. BOTH THE
GFS/ECMWF...TO SOME EXTENT...SHOW AN OPEN WAVE / INVERTED TROUGH
PASSING OVER THE AREA TUESDAY WITH A SLIGHT UPTICK IN RAIN CHANCES
AS IT MOVES BY.
&&
.AVIATION...THRU 11/12Z
WINDS: THRU 10/14Z...S/SW ARND 3KTS. BTWN 10/14Z-10/17Z...S/SW
6-9KTS. BTWN 10/17Z-10/19Z...BCMG S/SE 7-10KTS BTWN KMLB-KSUA.
BTWN 10/23Z-11/02Z...BCMG S/SW 4-6KTS ALL SITES.
VSBY/WX/CIGS: BTWN 10/17Z-11/02Z...SCT MVFR SHRAS/IFR TSRAS ALL
SITES...SLGT CHC +TSRA WITH SFC G35KTS S OF KISM-KTIX BTWN
10/21Z-11/01Z.
&&
.MARINE...
TODAY/TONIGHT...HI PRES RIDGE ANCHORED NE OF THE BAHAMA BANK
EXTENDING INTO THE WRN GOMEX WILL GENERATE A LIGHT TO GENTLE SWRLY
BREEZE OVER THE LCL ATLC...BCMG S/SE NEAR THE COAST S OF CAPE
CANAVERAL IN THE AFTN DUE TO THE FORMATION OF THE EAST COAST SEA
BREEZE. SEAS ARND 2-3FT. WINDS MAY FRESHEN TO A MODERATE SW BREEZE
OVER THE OFFSHORE LEG N OF SEBASTIAN INLET OVERNIGHT AS A FRONTAL
TROF PRESSES INTO THE DEEP SOUTH AND INTERACTS WITH THE RIDGE.
PRIMARY MARINE HAZARD WILL BE SCT AFTN TSTMS MOVING OFFSHORE DUE TO
THE PREVAILING S/SWRLY BREEZE...MAINLY FROM FT PIERCE INLET NWD.
FRI-SUN...RIDGE AXIS REMAINS OVER SOUTH HALF OF THE PENINSULA
THROUGH THE WEEKEND...ALLOWING FOR A LIGHT TO GENTLE SOUTH TO
SOUTHWEST BREEZE OVER THE LOCAL ATLANTIC WATERS. SOUTHWEST FLOW WILL
LIMIT THE DEVELOPMENT OF THE SEA BREEZE EACH DAY...ESPECIALLY NORTH
OF THE CAPE. SEAS 1 - 2 FEET NEARSHORE AND UP TO 3 FEET WELL
OFFSHORE. PRIMARY MARINE HAZARD WILL BE AFTERNOON THUNDERSTORMS
MOVING OFFSHORE WITH A GRADUAL INCREASE IN ACTIVITY EXPECTED EACH
DAY.
MON...FRONTAL BOUNDARY WILL WASH OUT OVER CENTRAL FLORIDA...LEADING
INITIALLY TO LIGHT NORTHERLY FLOW THAT WILL VEER TO EASTERLY EARLY
NEXT WEEK AS HIGH PRESSURE PUSHES OFF THE MID ATLANTIC.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 91 75 91 75 / 30 20 40 30
MCO 93 75 91 75 / 30 10 50 30
MLB 91 77 90 75 / 40 20 50 30
VRB 91 75 90 75 / 30 20 50 30
LEE 93 75 90 75 / 30 10 50 30
SFB 94 76 92 76 / 30 10 50 30
ORL 93 75 91 76 / 30 10 50 30
FPR 91 75 91 75 / 30 20 50 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...ULRICH
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1251 AM EDT THU SEP 10 2015
...UPDATED AVIATION DISCUSSION...
...FORECAST UPDATE...
ISSUED AT 955 PM EDT WED SEP 9 2015
SURFACE COLD FRONT AT 01Z WAS DRAPED ROUGHLY E-W OR NE-SW ACROSS
CENTRAL KY, ALTHOUGH EXACT POSITION A BIT DIFFICULT TO TELL, LIKELY
NEAR AN AXIS OF NEAR CALM WIND FROM LEX TO BWG. THERE ALSO APPEARED
TO BE A WEAK AREA OF LOW PRESSURE ROUGHLY NEAR THE SW KY/NW TN
BORDER ALONG THE BOUNDARY. AHEAD OF THIS LOW, RADAR SHOWED AN AREA
OF RAIN AND EMBEDDED STORMS OVER CENTRAL KY, ESPECIALLY BUTLER,
GRAYSON, AND EDMONSON COUNTIES AT 0145Z. IN FACT, RADAR LOOP
SUGGESTS A BROAD CIRCULATION ASSOCIATED WITH THE AREA OF RAIN.
EXPECT THE RAIN AND EMBEDDED CONVECTION TO PUSH ENE LATE THIS
EVENING INTO THE OVERNIGHT PERIOD WITH THE MESOSCALE SHORTWAVE
PROVIDING FORCING FOR LIFT. OCCASIONAL HEAVY RAIN MAY CONTINUE
ASSOCIATED WITH THIS FEATURE.
ELSEWHERE, WITH A BROAD SW-NE-ORIENTED MID-UPPER LEVEL MOISTURE
PLUME OVER THE OH AND TN VALLEYS AS SHOWN IN WATER VAPOR IMAGERY,
AND WITH THE WEAK SURFACE BOUNDARY/LOW IN THE VICINITY, SCATTERED
SHOWERS ARE EXPECTED OVER MUCH OF THE REMAINDER OF CENTRAL KY
OVERNIGHT, WITH THE BEST COVERAGE OVER SOUTHERN/EASTERN COUNTIES.
THERE SHOULD BE LITTLE PRECIP OVER MOST OF SOUTH-CENTRAL IN.
LATEST DATA SUGGESTS FOG MAY NOT BE AS MUCH OF A PROBLEM TOWARD
MORNING AS EARLIER EXPECTED, BUT STILL AREAS OF FOG AND LOWER CLOUDS
ARE EXPECTED AND RETAINED IN THE FORECAST. NO SIGNIFICANT CHANGES TO
TEMPS NEEDED OVERNIGHT FROM ONGOING FORECAST.
.SHORT TERM (NOW THROUGH THURSDAY NIGHT)...
ISSUED AT 245 PM EDT WED SEP 9 2015
AS OF MID AFTERNOON...WATER VAPOR IMAGERY AND 500 MB HEIGHTS SHOWED
A SHORTWAVE TROUGH EXTENDING FROM THE GREAT LAKES DOWN ALONG THE
MISSISSIPPI RIVER...JUST WEST OF CENTRAL KENTUCKY. AT THE
SURFACE...THE ENVIORNMENT IS CHARACTERIZED BY WARM AND MOIST AIR
WITH DEWPOINTS IN THE LOW 70S. A COLD FRONT LIED ALONG THE OHIO
RIVER...SLOWLY MOVING EAST THROUGH THE AREA.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY IN THE WARM
SECTOR WILL CONTINUE THROUGH THE LATE AFTERNOON HOURS. THESE STORMS
WILL BE CAPABLE OF PROUDCING BRIEF BUT VERY HEAVY RAINFALL GIVEN THE
HIGH PWATS IN THE AREA. SOME GUSTY WINDS ARE POSSIBLE AS WELL.
HI-RES MODELS SUCH AS THE HRRR AND 12Z SPC WRF ARE IN GOOD AGREEMENT
SHOWING THE HIGHEST CHANCES NOW THROUGH EARLY EVENING...THEN A
DECREASE IN COVERAGE AS THE UPPER SHORTWAVE TROUGH KICKS THE FRONT
EAST THROUGH THE AREA. A SECONDARY LOW PRESSURE AND TROUGH NEAR
MEMPHIS WILL TRACK THROUGH CENTRAL TN TO SOUTHEAST KY
OVERNIGHT...KEEPING SOME SHOWERS AND STORMS IN THE FORECAST MAINLY
OVERNIGHT FOR THE SOUTHERN FORECAST AREA. AREAS NORTH OF THE KY
PARKWAYS INTO SOUTHERN INDIANA WILL PROBABLY SEE THE END OF THE RAIN
FROM THIS SYSTEM THIS EVENING OR EARLY OVERNIGHT.
LOW CLOUDS AND/OR FOG IS A CONCERN OVERNIGHT INTO THE THURSDAY
MORNING COMMUTE AS THE BOUNDARY LAYER WILL REMAIN VERY MOIST WITH
LIGHT WINDS. SREF PROBABIALITIES FOR LOW CLOUDS /500 FT OR LESS/ AND
FOG ARE BETWEEN 40 AND 60 PERCENT. WILL HAVE TO WATCH FOR LOCALLY
DENSE POCKETS OF FOG...ESPECIALLY IF THERE IS ANY CLEARING OR BREAKS
IN THE CLOUDS TOWARD SUNRISE.
IMPROVING CONDITIONS CAN BE EXPECTED DURING THE DAY THURSDAY. SOME
LINGERING SHOWERS AND MAYBE A THUNDERSTORM WILL BE POSSIBLE ALONG
AND SOUTHEAST OF A LEXINGTON TO BOWLNG GREEN LINE DURING THE MORNING
BUT THIS SHOULD QUICKLY MOVE EAST BY NOON. NORTHWEST WINDS WILL PICK
UP...HELPING TO SCATTER OUT OR LIFT SOME OF THE CLOUDS IN THE
AREA. LOOK FOR HIGHS RIGHT AROUND NORMAL IN THE LOW 80S.
.LONG TERM (FRIDAY THROUGH WEDNESDAY)...
ISSUED AT 305 PM EDT WED SEP 9 2015
THE LONG TERM PERIOD WILL START OUT WITH A COLD FRONT PASSAGE ON
FRIDAY BRINGING SHOWERS/STORMS TO THE AREA FRI/FRI NIGHT. ALTHOUGH
THE OVERALL FORCING NEAR THE FRONT AND WIND SHEAR LOOK RELATIVELY
WEAK, THERE MAY BE ENOUGH SFC INSTABILITY TO PRODUCE A FEW STRONG
CELLS DURING THE AFTERNOON HOURS FRIDAY. OVERALL THOUGH, DON`T SEE
A BIG THREAT FOR ORGANIZED STRONG TO SEVERE CONVECTION FOR FRIDAY.
THE BIGGER STORY WITH THIS FRONT WILL BE THE STRONG UPPER LOW AND
MUCH COOLER AIRMASS FOLLOWING IT. WITH THESE FEATURES IN PLACE FOR
THE WEEKEND, LOOK FOR TEMPS TO BE 6 TO 12 DEGREES BELOW NORMAL.
SATURDAY WE`LL HAVE PLENTY OF LOW CLOUDS AND LINGERING SHOWERS
LIMITING HIGHS TO THE MID TO UPPER 60S. SOME MODEL DATA SUGGESTS
PERHAPS WE COULD SEE AN ISLD RUMBLE OF THUNDER WITH THIN, SHALLOW
INSTABILITY PRESENT IN THE SOUNDINGS. SHOWER ACTIVITY SHOULD
CONTINUE INTO SAT NIGHT BEFORE GRADUALLY ENDING FROM WEST TO EAST
SUN MORNING. HIGHS ON SUNDAY WILL BE SIMILAR TO SAT IN THE MID TO
UPPER 60S. LOW TEMPERATURES THIS WEEKEND WILL RANGE FROM THE MID
40S TO LOWER 50S WITH THE COOLEST NIGHT BEING SUN NIGHT INTO MONDAY
MORNING WHEN SKIES WILL BECOME CLEAR WITH THE HIGH PRESSURE CENTER
OVER THE REGION.
WE`LL REMAIN DRY MON-WED WITH RETURN FLOW BRINGING WARMER TEMPS BACK
INTO THE REGION. HIGHS ON MONDAY WILL WARM BACK INTO THE LOWER 70S
WITH UPPER 70S/LOWER 80S EXPECTED BY TUES/WED UNDER MOSTLY SUNNY
SKIES.
&&
.AVIATION (06Z TAF UPDATE)...
ISSUED AT 1250 AM EDT THU SEP 10 2015
SCATTERED SHOWERS CONTINUE TO MOVE ACROSS CENTRAL KENTUCKY TONIGHT.
THE BEST CHANCES FOR SHOWERS WILL SHIFT EAST THROUGH THE REMAINDER
OF THE NIGHT AND INTO TOMORROW MORNING. WILL THEREFORE CARRY VCSH AT
LEX FOR THE LONGEST, INTO THE DAYLIGHT HOURS.
FOG AND LOW CEILINGS WILL BECOME A CONCERN THIS MORNING WITH AMPLE
LOW LEVEL MOISTURE AND LIGHT WINDS. GUIDANCE SUGGEST CONDITIONS WILL
BE THE WORST AT BWG WHERE IFR (POSSIBLY LOWER) CEILINGS LOOK TO
DEVELOP THIS MORNING. WILL KEEP THE FORECAST MORE OPTIMISTIC AT SDF
AND LEX WITH JUST MVFR CEILINGS. HOWEVER, WILL HAVE TO WATCH THESE
CLOSELY.
WINDS WILL BE LIGHT AND VARIABLE TO CALM TONIGHT AND OUT OF THE
NORTH THROUGH THE DAY. CONDITIONS SHOULD IMPROVE TO VFR AT ALL SITES
BY LATE MORNING TO EARLY AFTERNOON.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.........TWF
SHORT TERM.....ZBT
LONG TERM......AMS
AVIATION.......EER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
506 AM EDT THU SEP 10 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT THU SEP 10 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A TROF EXTENDING S INTO
THE NCNTRL STATES AND UPPER GREAT LAKES...ANCHORED BY A MID LEVEL
LOW OVER NRN ONTARIO. SHORTWAVE MOVING ACROSS NRN ONTARIO IS HELPING
TO DRIVE A COLD FRONT SE...CURRENTLY ACROSS WRN LAKE SUPERIOR. DEEP
LAYER FORCING PER QVECTORS IS SUPPORTING AN AREA OF SHRA MOVING
ACROSS NE WI INTO SCNTRL UPPER MI EARLY THIS MORNING. ISOLD SHRA
HAVE BEEN OCCURRING FARTHER N TO LAKE SUPERIOR. EVEN A TSTM WAS
NOTED OVER ERN LAKE SUPERIOR A FEW HRS AGO.
AS FORCING SUPPORTING THE NE WI PCPN SHIFTS E...THIS MORE ORGANIZED
SHRA AREA WILL MOVE ACROSS THE SCNTRL AND PORTIONS OF THE ERN FCST
AREA OVER THE NEXT FEW HRS. THIS MAIN AREA OF PCPN SHOULD BE E OF
THE AREA NO LATER THAN MID MORNING. WITH COLD FRONT STILL PUSHING
SE...POTENTIAL IS THERE FOR ADDITIONAL ISOLD TO SCT SHRA DEVELOPMENT
UNTIL FROPA. THIS POTENTIAL SHOULD INCREASE DURING THE AFTN AS SOME
INSTABILITY BUILDS UP AHEAD OF COLD FRONT. DEVELOPING LAKE BREEZE
OFF LAKE MICHIGAN WILL ALSO STRENGTHEN THE LOW-LEVEL CONVERGENCE
ALONG THE SE MOVING COLD FRONT. RAP AND GFS SHOW MLCAPES UPWARDS OF
200-300J/KG OVER THE SCNTRL/SE FCST AREA. 00Z NAM SHOWED MLCAPE OVER
1000J/KG. WHILE THE 06Z NAM HAS PULLED BACK TO 600-800J/KG...IT
STILL LOOKS OVERDONE. IN ANY EVENT...THE AVBL INSTABILITY SUGGESTS
THE POTENTIAL FOR ISOLD TSTMS OVER THE SCNTRL/SE FCST AREA THIS AFTN
ALONG/AHEAD OF COLD FRONT.
CAA TODAY/TONIGHT WILL DROP 850MB TEMPS DOWN TO 0 TO 2C OVER LAKE
SUPERIOR BY 12Z FRI...SUFFICIENT FOR LAKE EFFECT PROCESSES WITH
WATER TEMPS ROUGHLY 15-18C. WITH NAM/GFS FCST SOUNDINGS SHOWING A
WELL MIXED LAYER IN LOWER 2KFT OF THE AIR MASS...BELIEVE IT WILL
TAKE SOME TIME TO GET LAKE EFFECT GOING TONIGHT...ESPECIALLY IN
LIGHT OF THE LACK OF SYNOPTIC SUPPORT WITH DEEP LAYER QVECTOR
DIVERGENCE DOMINATING. NOT EXPECTING ANYTHING MORE THAN ISOLD TO
PERHAPS SCT -SHRA COVERAGE. WITH WATER TEMPS MORE IN THE 12-15C
RANGE OVER THE ERN LAKE...-SHRA COVERAGE WILL BE LEAST OVER THE ERN
FCST AREA. IN FACT...THERE MAY NOT BE ANY LAKE EFFECT -SHRA OVER THE
FAR E TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 316 AM EDT THU SEP 10 2015
UPPER PATTERN CONSISTS OF A 500 MB RIDGE OVER THE WESTERN U.S. WITH
A TROUGH OVER THE UPPER GREAT LAKES 12Z FRI WITH A DEEP TROUGH OVER
THE EAST HALF OF THE U.S. THE TROUGH AXIS IS OVER THE CWA 12Z FRI
AND SLOWLY MOVES TO THE EAST BY 00Z SAT. THE TROUGH CONTINUES TO DIG
SOUTHEAST WITH A DEEP TROUGH OVER THE ERN U.S. ON SAT.
WITH THE TROUGH AXIS MOVING ACROSS THE AREA ON FRI...STILL NEED TO
KEEP SOME POPS IN THE FORECAST ESPECIALLY FOR DIURNALLY DRIVEN
SHOWERS. ALSO IS COLD ENOUGH FOR LAKE EFFECT CONTRIBUTION AS WELL AS
LAKE SUPERIOR TEMPERATURES RANGE FROM 10C TO 15C AND 850 MB RANGE
FROM 0C TO 2C ON FRIDAY AND THAT IS ENOUGH LAKE-850 MB DELTA-T TO
DEFINITELY HAVE SOME LAKE CONTRIBUTION TO THE PCPN AS WELL. WITH
LOSS OF DIURNAL HEATING FRI NIGHT...DRY THINGS OUT AND KEEP THAT WAY
THROUGH SAT NIGHT. DID NOT MAKE TOO MANY CHANGES TO THE GOING
TEMPERATURES AS THEY LOOKED FINE. KEPT IN SOME PATCHY FROST FOR FRI
NIGHT AND SAT NIGHT IN THE INTERIOR WEST AS LOWS FALL TO THE MID 30S.
IN THE EXTENDED...GFS AND ECMWF SHOW A CLOSED 500 MB LOW OVER THE
LOWER GREAT LAKES 12Z SUN WITH A RIDGE OVER THE DESERT SW. SFC FRONT
ON IS PARALLEL WITH UPPER FLOW ON SUNDAY ACROSS SOUTH CENTRAL
CANADA. A BROAD 500 MB TROUGH OVER THE NORTHERN ROCKIES 12Z MON WILL
DIGS SOUTHEAST 12Z TUE WITH A SFC FRONT BECOMING STATIONARY OVER THE
AREA ON TUE. AS A RIDGE BUILDS INTO THE EASTERN U.S. ON WED...THIS
FRONT WILL HEAD BACK NORTH AS A WARM FRONT ON WED. WILL BE A WARMING
TREND STARTING ON MON WITH TEMPERATURES GOING ABOVE NORMAL. HAVE
SOME SLIGHT CHANCE POPS IN FOR TUE AND TUE NIGHT WITH THE FRONT NEAR
THE AREA AND CHANCE POPS ON WED AS THE FRONT MOVES NORTH AS A WARM
FRONT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 136 AM EDT THU SEP 10 2015
EXPECT VFR CONDITIONS THROUGH MOST OF THE FCST PERIOD. VFR CIGS WITH
MID CLOUDS WILL PREVAIL OVERNIGHT AS A DISTURBANCE MOVES THROUGH THE
REGION. THERE MAY BE A FEW SHOWERS OR SPRINKLES BUT MOST OF THE PCPN
IS EXPECTED TO REMAIN SOUTH OF THE TAF SITES AS FAIRLY DRY AIR
LINGERS IN THE LOWER LEVELS...KEEPING CIGS AOA 5K FT. AS A COLD FRONT
MOVES THROUGH TODAY AND WINDS VEER NRLY BY EVENING...THE COMBINATION
OF CAA AND INCREASING LOW LEVEL MOISTURE WITH UPSLOPE FLOW SHOULD
DROP CIGS INTO THE MVFR RANGE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT THU SEP 10 2015
PASSING COLD FRONT THIS MORNING FOLLOWED BY INCREASINGLY COLDER AIR
FLOWING INTO THE UPPER GREAT LAKES WILL RESULT IN INCREASING WINDS
ON LAKE SUPERIOR TODAY AND TONIGHT. WINDS SHOULD BE MOSTLY UNDER
20KT THRU THE MORNING BEFORE GUSTS RAMP UP AND REACH 20-30KT
TONIGHT. STRONGEST WINDS SHOULD BE ACROSS CNTRL LAKE SUPERIOR. WHILE
WINDS WILL SLOWLY DIMINISH OVER THE WRN LAKE ON FRI...20-30KT WINDS
WILL CONTINUE OVER THE E. HIGH PRES RIDGE ARRIVES SAT...RESULTING IN
WINDS FALLING OFF TO UNDER 15KT. INCREASING S TO SW WINDS ARE
EXPECTED SUN INTO MON AS HIGH PRES RIDGE DEPARTS AND A LOW PRES TROF
APPROACHES FROM THE NW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...07
AVIATION...JLB
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS BILLINGS MT
243 AM MDT THU SEP 10 2015
.SHORT TERM...VALID FOR TDY AND FRI...
SEASONABLY WARM TEMPERATURES...LIGHT WINDS AND MAINLY DRY WEATHER
WILL CONTINUE TODAY AND FRIDAY.
TODAY...WE HAVE LINGERED A LOW-END SHOWER CHANCE OVER SOUTHEASTERN
MT THROUGH NOON MDT...AND WE DID DECIDE TO PULL THAT SLIGHT CHANCE
OF SHOWERS BACK SOUTHWEST INTO THE SHERIDAN AREA TOO. THAT WAS ALL
BASED ON OVERNIGHT RADAR TRENDS AS OF 0830 UTC AND RECENT RUNS OF
THE EXPERIMENTAL AND OPERATIONAL HRRR MODEL. THE SHORTWAVE TROUGH
RESPONSIBLE FOR THE EARLY-DAY SHOWER CHANCE WILL MOVE SOUTHEAST OF
THE AREA BY AFTERNOON AND SO WE DECIDED TO GO WITH A DRY FORECAST
EVERYWHERE AFTER 18 UTC EVEN THOUGH WE CANNOT ENTIRELY RULE OUT A
SPRINKLE IN SOUTHEASTERN MT THIS AFTERNOON. FORECAST HIGHS TODAY
WERE DRIVEN BY THE 00 UTC MULTI-MODEL CONSENSUS...AND ARE MAINLY
IN THE 70S F ON RELATIVELY LIGHT NORTH-NORTHEAST WINDS.
TONIGHT...THE 00 UTC GUIDANCE SHOWED ANOTHER AND WEAKER SHORTWAVE
TROUGH CROSSING SOUTHEASTERN MT IN NORTHWEST FLOW ALOFT DURING THE
EVENING. HOWEVER...WE CHOSE TO STAY WITH A DRY FORECAST FOR NOW AS
THE QG-FORCING WITH THE WAVE IS WEAK...THERE/S VERY LITTLE QPF IN
MODEL SIMULATIONS...AND MOS-BASED POPS ARE ALL BELOW 15 PERCENT.
WE THUS EXPECT A QUIET NIGHT WITH LOWS MAINLY IN THE 40S F ACROSS
THE AREA AS SURFACE HIGH PRESSURE SLIDES SOUTH ACROSS THE DAKOTAS.
FRIDAY...FLOW ALOFT WILL TURN DECIDEDLY ANTI-CYCLONIC AS A 500-MB
RIDGE OVER THE WESTERN UNITED STATES BUILDS EASTWARD. THE AIR MASS
WILL WARM AS A RESULT AND THUS TEMPERATURES WILL BE A BIT WARMER
THAN TODAY. SOME AREAS WILL LIKELY BE NEAR 80 F IN SOUTH CENTRAL
MT AND NORTH CENTRAL WY...BUT FORECAST SOUNDINGS SUGGEST MIXING
MAY BE SOMEWHAT LIMITED BY A SUBSIDENCE INVERSION JUST ABOVE 700
MB. WE RELIED ON THE 00 UTC MULTI-MODEL CONSENSUS FOR HIGHS GIVEN
THIS SCENARIO AND LITTLE SPREAD IN GUIDANCE OUTPUT. SCHULTZ
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
PATTERN CONTINUES TO LOOK WARM TO START...COOLER TO FINISH. AN
UPPER RIDGE WILL BUILD SATURDAY AND GET FLATTENED OUT BY ENERGY
RIDING ACROSS SOUTHERN CANADA ON SUNDAY. BACKING FLOW WITH
LOWERING HEIGHTS ON TAP FOR SUNDAY...BUT DESPITE THIS...BUMPED UP
FORECAST HIGHS. DOWNSLOPE FLOW WILL BE INCREASING WITH STRONGER
700MB WINDS IN A PRE FRONTAL ENVIRONMENT. RAISED HIGHS ON SUNDAY
TO MATCH THOSE OF SATURDAY. A COLD FRONT WILL PUSH THROUGH THE
AREA SUNDAY EVENING AND PROVIDE A COOLER DAY MONDAY.
MODELS THEN DIVERGE FROM TUESDAY ONWARD AND THE DIFFERENCES STEM
FROM THE DEVELOPING WESTERN TROUGH. THE GFS WAS STRONGER WITH THE
SOUTHERN STREAM ENERGY OF THE TROUGH AND THEREFORE DEEPER WITH IT
IN THE GREAT BASIN. THE ECMWF SWEEPS THE STRONGER ENERGY NORTH AND
WAS FLATTER WITH THE SOUTHERN EXTENT OF THE TROUGH FOR WARMER AND
DRIER WEATHER FOR TUESDAY. SINCE BOTH MODELS HIT THE AREA...IN
PARTICULAR THE WEST...WITH QPF...RAISED POPS FOR TUESDAY AND
TUESDAY NIGHT. DIFFERENCES EXIST FOR WEDNESDAY AS THE GFS WAS
WARMER AND DRIER WITH ZONAL FLOW...WHILE THE ECMWF MAINTAINS A
SOUTHWEST FLOW AND SENDS ENERGY UP FOR CHANCE POPS. TWH
&&
.AVIATION...
A FAIRLY QUIET WEATHER PATTERN WILL REMAIN IN PLACE WITH VFR
FLYING CONDITIONS EXPECTED. A WEAK DISTURBANCE WILL CREATE A FEW
SPRINKLES OR SOME VIRGA OVER SOUTHEAST MONTANA AND NORTHEAST
WYOMING THIS MORNING. OTHERWISE...NO PRECIPITATION EXPECTED WITH
CLOUDS BASES ABOVE 10 THOUSAND FEET. WINDS WILL BE LIGHT. TWH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 075 049/079 051/090 057/090 055/076 052/069 042/066
1/B 00/U 00/U 00/U 12/T 33/T 32/W
LVM 077 043/081 045/088 051/088 050/076 045/063 042/063
0/B 00/U 00/U 11/U 12/T 33/T 32/W
HDN 077 047/080 049/090 055/090 054/079 051/073 042/068
1/B 00/U 00/U 00/U 12/T 23/T 32/W
MLS 074 047/076 049/088 057/088 055/078 050/072 046/067
2/W 10/U 00/U 00/U 12/T 22/T 32/W
4BQ 073 047/075 049/086 056/089 056/080 051/073 049/070
2/W 10/U 00/U 00/U 11/B 22/T 42/W
BHK 070 045/072 046/083 053/086 053/078 049/073 048/067
2/W 10/U 00/U 00/U 12/T 22/T 32/W
SHR 076 044/078 045/087 050/088 051/080 048/073 044/069
2/W 10/U 00/U 00/U 12/T 23/T 41/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
203 AM CDT THU SEP 10 2015
.SYNOPSIS...
ISSUED AT 302 PM CDT WED SEP 9 2015
AS OF WEDNESDAY AFTERNOON THE UPPER AIR SYNOPTIC PATTERN OVER THE
CONTINUED TO BE HIGHLIGHTED BY A BROAD TROUGH ASSOCIATED WITH A LOW
SLOWLY MOVING TOWARD HUDSON BAY. THIS HAS THE NORTHERN AND CENTRAL
PLAINS IN RELATIVELY FAST NORTHWEST FLOW ALOFT. COOLER AIR IN THE
MID TO UPPER LEVEL OF THIS FLOW FOSTERED AN ENVIRONMENT
CHARACTERIZED BY STEEP LAPSE RATES AND ELEVATED INSTABILITY...WHICH
HAS AIDED IN THE FORMATION AND PERSISTENCE OF ISOLATED TO SCATTERED
THUNDERSTORM ACTIVITY IN CENTRAL NEBRASKA LATE IN THE MORNING AND
EARLY THIS AFTERNOON. AT THE SURFACE...A WEAK FRONT WAS SLOWLY
MOVING EAST ACROSS THE CWA. AS OF 20Z THE FRONT EXTENDED FROM JUST
EAST OF IMPERIAL AND NORTH PLATTE...NORTHEASTWARD TO NEAR AINSWORTH.
DRY WESTERLY WINDS BEHIND THE FRONT HAD DEWPOINTS DROPPING INTO THE
30S AND 40S ACROSS THE PANHANDLE AND WESTERN SANDHILLS. AHEAD OF
THE FRONT WINDS WERE SOUTHERLY AND DEWPOINTS REMAINED IN THE UPPER
50S AND 60S...WITH A CU FIELD DEVELOPING AS THE BOUNDARY LAYER
BECOMES MORE UNSTABLE. TEMPERATURES WERE GENERALLY IN THE MID 80S.
&&
.UPDATE...
ISSUED AT 158 AM CDT THU SEP 10 2015
STRATUS DEVELOPING IN THE PLATTE RIVER VALLEY HAS PROMPTED AN
UPDATE TO THE SKY CONDITION IN THE FORECAST FOR LINCOLN COUNTY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 302 PM CDT WED SEP 9 2015
THUNDERSTORMS IN CENTRAL AND NORTH CENTRAL NEBRASKA SHOULD CONTINUE
TO SLOWLY PUSH EAST THROUGH THE REMAINDER AFTERNOON. CONVECTIVE
ACTIVITY HAS ACCELERATED OVER CENTRAL ROCK AND HOLT COUNTY. SOME
LOCATIONS ARE RECEIVING HEAVY RAINFALL DUE TO TRAINING
STORMS...HOWEVER LATEST FFG IN THIS AREA IS QUITE HIGH. ADDITIONAL
SURFACE BASED SHOWERS AND THUNDERSTORM DEVELOPMENT HAS BEGUN IN FAR
SOUTHWEST NEBRASKA AND NORTHWEST KANSAS ALONG AN EASTWARD
PROGRESSING FRONT. HRRR HAS FAVORED AREAS JUST EAST OF A NORTH
PLATTE TO THEDFORD MUCH OF THE DAY...AND THIS MATCHES UP WELL WITH
THE DEVELOPING CU FIELD ON SATELLITE SO THE FORECAST LOOKS ON TRACK.
UPPER LEVEL FORCING IS TOUGH TO DISCERN SO THE SPATIAL EXTENT OF THE
NEW CONVECTION IS NOT EXPECTED TO BE EXPANSIVE. MLCAPE VALUES 1500
J/KG AND 35-40 KTS DEEP LAYER SHEAR WILL SUPPORT A FEW STRONG TO
SEVERE STORMS...HOWEVER WIDESPREAD SEVERE WEATHER IS NOT EXPECTED.
THUNDERSTORMS PUSH EAST THIS EVENING AND BEGIN TO WANE AFTER DARK
WITH THE LOSS OF HEATING AND INSTABILITY.
WEAK SHORTWAVE TROUGH DIVES SOUTHEAST THROUGH THE AREA OVERNIGHT.
WINDS BECOME EASTERLY AS THE FRONT SLOWLY PUSHES JUST SOUTHEAST OF
THE CWA AND A LEE SIDE SURFACE LOW DEEPENS IN NORTHEAST COLORADO.
THIS WILL ALLOW LOW LEVEL MOISTURE TO CREEP BACK WESTWARD...WITH
ANOTHER ROUND OF FOG/STRATUS POSSIBLE FOR SOUTHWEST INTO CENTRAL
NEBRASKA. DID NOT INCLUDE PATCHY FOG IN THE FORECAST AT THIS TIME
SINCE MODEL GUIDANCE HAS BEEN SOMEWHAT INCONSISTENT WITH COVERAGE
AND SEVERITY OF VISIBILITY RESTRICTIONS. THE MOST FAVORABLE AREAS
FOR LOCALLY DENSE FOG FORMATION WILL LIKELY BE WHERE PRECIPITATION
FALLS LATER THIS EVENING.
AN AREA OF SURFACE HIGH PRESSURE BEGINS TO DROP OUT OF ALBERTA AND
INTO THE NORTHERN PLAINS ON THURSDAY. THIS WILL PUSH TEMPERATURES
DOWN A FEW DEGREES WITH HIGHS RANGING FROM THE LOW 70S TO LOW 80S
ACROSS THE CWA. MODELS ADVERTISE LIGHT QPF LATE IN THE AFTERNOON AS
A MID-LEVEL JET STREAK NOSES INTO THE CENTRAL PLAINS...BUT DID NOT
ADD ANY MENTION OF POPS TO THE SHORT TERM FORECAST JUST YET AS THE
BETTER CHANCES LOOK TO BE AFTER 00Z FRIDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 302 PM CDT WED SEP 9 2015
THE NAM REMAINS IN AGREEMENT WITH CURRENT FORECAST WITH A
DISTURBANCE DROPPING SOUTHEAST FROM SWRN SD INTO WRN NEBR
OVERNIGHT. THE GFS IS FASTER WITH THIS DISTURBANCE AND REMAINS
MOSTLY DRY. THEREFORE KEPT POPS LIMITED TO 20 PERCENT WEST OF A
LINE FROM GORDON THROUGH BROKEN BOW.
KEPT VERY NEAR PREVIOUS HIGHS FRIDAY AS EASTERLY WINDS BECOME
SOUTHEAST BY AFTERNOON AND WEAK WAA WILL NOT KICK IN UNTIL
AFTERNOON. THERE COULD ALSO BE A FEW SHOWERS AND CLOUDINESS
LINGERING AS WELL.
ON SATURDAY...A RETURN SOUTHERLY WIND RETURNS WITH HIGHS WARMING
TO NEAR 80 ACROSS THE WEST WHILE THE EAST REMAINS IN THE LOWER TO
MID 70S.
FOR SUNDAY THROUGH TUESDAY...ABOVE NORMAL TEMPERATURES. ZONAL FLOW
ALOFT ACROSS THE CENTRAL PLAINS SUNDAY WILL PERSIST INTO MONDAY AS
AN UPPER TROUGH DIGS INTO THE PACIFIC NORTHWEST. THIS WILL KEEP A
THERMAL RIDGE ACROSS THE REGION WITH HIGHS RANGING IN THE 80S. ON
TUESDAY...THE UPPER TROUGH WILL ADVANCE ACROSS MONTANA THROUGH
COLORADO WITH STRONG HEATING TO OCCUR IN ADVANCE ACROSS THE
CENTRAL PLAINS. FORECAST HIGH ARE 85 TO 90...ALTHOUGH THE
POTENTIAL IS THERE FOR HIGHS TO EXCEED 90 IN SOME AREAS OF WRN
NEBR. A COLD FRONT TUESDAY NIGHT TO COOL BACK HIGHS TO NEAR 75
NORTH AND NEAR 80 SOUTH. THE 12Z ECMWF HOWEVER IS MUCH WEAKER WITH
THE POST FRONTAL COOLDOWN AND SUGGESTS 80S STILL POSSIBLE. MAINLY
DRY THROUGH THE EXTENDED PERIODS...EXCEPT A SLIGHT CHANCE ERN
PNHDL TUESDAY AFTN...AND MOST AREAS TUESDAY NIGHT. LOOKS DRY
BEHIND THE FRONT FOR WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 158 AM CDT THU SEP 10 2015
STRATUS IN SOUTHWEST NEBRASKA HAS REDUCED CEILING BELOW 600 FEET
AGL AT LBF. CURRENT INDICATIONS ARE THAT THE STRATUS WILL CONTINUE
AND...WITH EAST WIND JUST OFF OF THE SURFACE...WILL PROBABLY
INCREASE IN COVERAGE. HOWEVER...THE LOWEST DECK MAY LIFT
OCCASIONALLY OR SCATTER TO 600 FEET OR ABOVE THOUGH IT IS UNLIKELY
THAT THE CEILING WILL LIFT TO 1000 FEET AGL OR HIGHER.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SPRINGER
SYNOPSIS...MARTIN
SHORT TERM...MARTIN
LONG TERM...ROBERG
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1141 PM CDT WED SEP 9 2015
.SYNOPSIS...
ISSUED AT 302 PM CDT WED SEP 9 2015
AS OF WEDNESDAY AFTERNOON THE UPPER AIR SYNOPTIC PATTERN OVER THE
CONTINUED TO BE HIGHLIGHTED BY A BROAD TROUGH ASSOCIATED WITH A LOW
SLOWLY MOVING TOWARD HUDSON BAY. THIS HAS THE NORTHERN AND CENTRAL
PLAINS IN RELATIVELY FAST NORTHWEST FLOW ALOFT. COOLER AIR IN THE
MID TO UPPER LEVEL OF THIS FLOW FOSTERED AN ENVIRONMENT
CHARACTERIZED BY STEEP LAPSE RATES AND ELEVATED INSTABILITY...WHICH
HAS AIDED IN THE FORMATION AND PERSISTENCE OF ISOLATED TO SCATTERED
THUNDERSTORM ACTIVITY IN CENTRAL NEBRASKA LATE IN THE MORNING AND
EARLY THIS AFTERNOON. AT THE SURFACE...A WEAK FRONT WAS SLOWLY
MOVING EAST ACROSS THE CWA. AS OF 20Z THE FRONT EXTENDED FROM JUST
EAST OF IMPERIAL AND NORTH PLATTE...NORTHEASTWARD TO NEAR AINSWORTH.
DRY WESTERLY WINDS BEHIND THE FRONT HAD DEWPOINTS DROPPING INTO THE
30S AND 40S ACROSS THE PANHANDLE AND WESTERN SANDHILLS. AHEAD OF
THE FRONT WINDS WERE SOUTHERLY AND DEWPOINTS REMAINED IN THE UPPER
50S AND 60S...WITH A CU FIELD DEVELOPING AS THE BOUNDARY LAYER
BECOMES MORE UNSTABLE. TEMPERATURES WERE GENERALLY IN THE MID 80S.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 302 PM CDT WED SEP 9 2015
THUNDERSTORMS IN CENTRAL AND NORTH CENTRAL NEBRASKA SHOULD CONTINUE
TO SLOWLY PUSH EAST THROUGH THE REMAINDER AFTERNOON. CONVECTIVE
ACTIVITY HAS ACCELERATED OVER CENTRAL ROCK AND HOLT COUNTY. SOME
LOCATIONS ARE RECEIVING HEAVY RAINFALL DUE TO TRAINING
STORMS...HOWEVER LATEST FFG IN THIS AREA IS QUITE HIGH. ADDITIONAL
SURFACE BASED SHOWERS AND THUNDERSTORM DEVELOPMENT HAS BEGUN IN FAR
SOUTHWEST NEBRASKA AND NORTHWEST KANSAS ALONG AN EASTWARD
PROGRESSING FRONT. HRRR HAS FAVORED AREAS JUST EAST OF A NORTH
PLATTE TO THEDFORD MUCH OF THE DAY...AND THIS MATCHES UP WELL WITH
THE DEVELOPING CU FIELD ON SATELLITE SO THE FORECAST LOOKS ON TRACK.
UPPER LEVEL FORCING IS TOUGH TO DISCERN SO THE SPATIAL EXTENT OF THE
NEW CONVECTION IS NOT EXPECTED TO BE EXPANSIVE. MLCAPE VALUES 1500
J/KG AND 35-40 KTS DEEP LAYER SHEAR WILL SUPPORT A FEW STRONG TO
SEVERE STORMS...HOWEVER WIDESPREAD SEVERE WEATHER IS NOT EXPECTED.
THUNDERSTORMS PUSH EAST THIS EVENING AND BEGIN TO WANE AFTER DARK
WITH THE LOSS OF HEATING AND INSTABILITY.
WEAK SHORTWAVE TROUGH DIVES SOUTHEAST THROUGH THE AREA OVERNIGHT.
WINDS BECOME EASTERLY AS THE FRONT SLOWLY PUSHES JUST SOUTHEAST OF
THE CWA AND A LEE SIDE SURFACE LOW DEEPENS IN NORTHEAST COLORADO.
THIS WILL ALLOW LOW LEVEL MOISTURE TO CREEP BACK WESTWARD...WITH
ANOTHER ROUND OF FOG/STRATUS POSSIBLE FOR SOUTHWEST INTO CENTRAL
NEBRASKA. DID NOT INCLUDE PATCHY FOG IN THE FORECAST AT THIS TIME
SINCE MODEL GUIDANCE HAS BEEN SOMEWHAT INCONSISTENT WITH COVERAGE
AND SEVERITY OF VISIBILITY RESTRICTIONS. THE MOST FAVORABLE AREAS
FOR LOCALLY DENSE FOG FORMATION WILL LIKELY BE WHERE PRECIPITATION
FALLS LATER THIS EVENING.
AN AREA OF SURFACE HIGH PRESSURE BEGINS TO DROP OUT OF ALBERTA AND
INTO THE NORTHERN PLAINS ON THURSDAY. THIS WILL PUSH TEMPERATURES
DOWN A FEW DEGREES WITH HIGHS RANGING FROM THE LOW 70S TO LOW 80S
ACROSS THE CWA. MODELS ADVERTISE LIGHT QPF LATE IN THE AFTERNOON AS
A MID-LEVEL JET STREAK NOSES INTO THE CENTRAL PLAINS...BUT DID NOT
ADD ANY MENTION OF POPS TO THE SHORT TERM FORECAST JUST YET AS THE
BETTER CHANCES LOOK TO BE AFTER 00Z FRIDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 302 PM CDT WED SEP 9 2015
THE NAM REMAINS IN AGREEMENT WITH CURRENT FORECAST WITH A
DISTURBANCE DROPPING SOUTHEAST FROM SWRN SD INTO WRN NEBR
OVERNIGHT. THE GFS IS FASTER WITH THIS DISTURBANCE AND REMAINS
MOSTLY DRY. THEREFORE KEPT POPS LIMITED TO 20 PERCENT WEST OF A
LINE FROM GORDON THROUGH BROKEN BOW.
KEPT VERY NEAR PREVIOUS HIGHS FRIDAY AS EASTERLY WINDS BECOME
SOUTHEAST BY AFTERNOON AND WEAK WAA WILL NOT KICK IN UNTIL
AFTERNOON. THERE COULD ALSO BE A FEW SHOWERS AND CLOUDINESS
LINGERING AS WELL.
ON SATURDAY...A RETURN SOUTHERLY WIND RETURNS WITH HIGHS WARMING
TO NEAR 80 ACROSS THE WEST WHILE THE EAST REMAINS IN THE LOWER TO
MID 70S.
FOR SUNDAY THROUGH TUESDAY...ABOVE NORMAL TEMPERATURES. ZONAL FLOW
ALOFT ACROSS THE CENTRAL PLAINS SUNDAY WILL PERSIST INTO MONDAY AS
AN UPPER TROUGH DIGS INTO THE PACIFIC NORTHWEST. THIS WILL KEEP A
THERMAL RIDGE ACROSS THE REGION WITH HIGHS RANGING IN THE 80S. ON
TUESDAY...THE UPPER TROUGH WILL ADVANCE ACROSS MONTANA THROUGH
COLORADO WITH STRONG HEATING TO OCCUR IN ADVANCE ACROSS THE
CENTRAL PLAINS. FORECAST HIGH ARE 85 TO 90...ALTHOUGH THE
POTENTIAL IS THERE FOR HIGHS TO EXCEED 90 IN SOME AREAS OF WRN
NEBR. A COLD FRONT TUESDAY NIGHT TO COOL BACK HIGHS TO NEAR 75
NORTH AND NEAR 80 SOUTH. THE 12Z ECMWF HOWEVER IS MUCH WEAKER WITH
THE POST FRONTAL COOLDOWN AND SUGGESTS 80S STILL POSSIBLE. MAINLY
DRY THROUGH THE EXTENDED PERIODS...EXCEPT A SLIGHT CHANCE ERN
PNHDL TUESDAY AFTN...AND MOST AREAS TUESDAY NIGHT. LOOKS DRY
BEHIND THE FRONT FOR WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1140 PM CDT WED SEP 9 2015
FOR THE KLBF TERMINAL...SKIES WILL BE MAINLY CLEAR OVERNIGHT WITH
A SMALL THREAT FOR FOG TOWARD SUNRISE THURSDAY. VISBYS MAY DROP AS
LOW AS 5SM FROM 10Z TO 14Z. HIGH CLOUDS WILL INCREASE BY MID
MORNING...WITH BROKEN CIGS OF 20000 FT AGL EXPECTED AFTER 19Z
THURSDAY. FOR THE KVTN TERMINAL...EXPECT SCATTERED TO BROKEN CIGS
AROUND 20000 FT AGL OVER THE NEXT 24 HRS...WITH SOME BROKEN CIGS
AROUND 10000 FT AGL EXPECTED AFTER 17Z THURSDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MARTIN
SHORT TERM...MARTIN
LONG TERM...ROBERG
AVIATION...CLB
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1145 PM MDT WED SEP 9 2015
.AVIATION...
06Z TAF CYCLE
SHOWERS HAVE MOVED OUT OF THE AREA. EXPECT VFR CONDITIONS AT THE
TAF SITES OVERNIGHT. LOW CLOUDS AND FOG NOT LIKELY TO OCCUR
TONIGHT AT KLVS...KTCC AND KROW...DUE TO THE HIGH CLOUD COVER
AND WINDS BECOMING MORE SW. CROP OF SHOWERS AND STORMS THURSDAY
PM WILL BE LESS IN COVERAGE AND INTENSITY...FAVORING THE NE WHERE
A COLD FRONT WILL BE APPROACHING...AND THE SOUTHERN HIGH TERRAIN.
&&
.PREV DISCUSSION...310 PM MDT WED SEP 9 2015...
.SYNOPSIS...
SCATTERED THUNDERSTORMS OVER CENTRAL NEW MEXICO WILL TAPER OFF THIS
EVENING. THE COVERAGE OF STORMS WILL FOCUS OVER SOUTHWEST NEW MEXICO
ON THURSDAY. DRIER AIR SETTLING INTO NORTHERN NEW MEXICO TONIGHT AND
THURSDAY NIGHT WILL ALLOW LOW TEMPERATURES TO SETTLE INTO THE 30S
AND 40S. A BACK DOOR COLD FRONT WILL SHIFT DOWN THE EASTERN PLAINS
ON FRIDAY ALLOWING FOR ANOTHER UPTICK IN STORMS. HIGH TEMPERATURES
WILL FALL BELOW NORMAL WITH MANY AREAS STAYING IN THE 70S. ISOLATED
STORMS ARE EXPECTED OVER THE WEEKEND BEFORE THE NEXT INCREASE IN
COVERAGE DEVELOPS MONDAY AND TUESDAY.
&&
.DISCUSSION...
THE COMBINATION OF A 40-50KT 300MB JET CORE AND MOIST UNSTABLE
UPSLOPE FLOW ALONG THE EAST SLOPES OF THE CENTRAL MT CHAIN TODAY
HAS LED TO A FEW STRONG TO LOCALLY SEVERE STORMS. SPC SSEO PICKED
UP ON THE COVERAGE AREA VERY WELL. HRRR AND LOCAL WRF SHOW THIS
ACTIVITY TAPERING OFF DURING THE EVENING WHILE DRYING TAKES PLACE
FROM NORTH TO SOUTH. SFC DEWPOINTS FROM THE NAM12 SHOW UPPER 20S/
LOW 30S TONIGHT ACROSS THE NW HALF OF THE STATE...WHICH COMBINED
WITH RADIATIONAL COOLING WILL LEAD TO CHILLY TEMPS. ANGEL FIRE IS
EXPECTED TO HIT FREEZING FOR THE 1ST TIME SINCE AUGUST 5TH.
THE AXIS FOR MOIST INSTABILITY WILL SHIFT FARTHER SOUTH THURSDAY
INTO SW NM WHILE DRY AIR ALOFT CONTINUES PRESSING S/SE OVER NORTHERN
NM. A FEW STORMS ARE STILL LIKELY AS WEAKLY FAVORABLE UPPER LEVEL
JET DYNAMICS DRIFT SOUTH OUT OF COLORADO. AT THE SURFACE THE FIRST
SIGNS OF A BACK DOOR FRONT WILL FLIRT WITH THE FAR NE PLAINS THUS
PROVIDING YET ANOTHER FORCING MECHANISM WITHIN COLFAX AND UNION
COUNTIES. THIS FRONT WILL SURGE INTO EASTERN NM AND THRU GAPS IN
THE CENTRAL MT CHAIN FRIDAY. MEANWHILE A 590DM H5 HIGH CENTER
WILL BECOME POSITIONED OVERHEAD AND FOCUS MORE TERRAIN DOMINATED
STORM COVERAGE FRIDAY THROUGH THE WEEKEND.
EXTENDED MODEL GUIDANCE IS GOING TO HAVE A DIFFICULT TIME WITH
THE REMNANTS OF HURRICANE LINDA NEXT WEEK AS SEVERAL DISORGANIZED
UPPER LEVEL VORT FEATURES TAKE SHAPE ALONG THE WEST COAST. FOR NOW
IT APPEARS MONDAY/TUESDAY COULD FEATURE AN UPTICK IN STORM
COVERAGE AS A PORTION OF THE 700-500MB MOISTURE AXIS CROSSES NM.
GUYER
&&
.FIRE WEATHER...
A NEW CENTROID OF HIGH PRESSURE HAS TAKEN SHAPE OVER THE GREAT
BASIN. THIS WILL FUNNEL DRIER AIR OVER NM FROM THE NORTHWEST WITH
MINIMUM HUMIDITIES FALLING A FEW TO 14 DEGREES ACROSS THE FORECAST
AREA THURSDAY. SINCE LOW LEVEL FLOW WILL ALSO TAKE ON MORE OF A
SOUTHWESTERLY COMPONENT ON THURSDAY...THERE WILL BE A DOWNTICK IN
SHOWER AND THUNDERSTORM COVERAGE WITH MAINLY ISOLATED ACTIVITY
FAVORING LOCATIONS ALONG AND EAST OF THE CONTINENTAL DIVIDE.
A STRONGER BACK DOOR COLD FRONT FRIDAY WILL BRING WITH IT MORE
MOISTURE WITH AN UPTICK IN SHOWER AND THUNDERSTORM ACTIVITY ALONG
AND EAST OF THE CENTRAL MOUNTAIN CHAIN DURING THE AFTERNOON...THEN
AS FAR WEST AS THE CONTINENTAL DIVIDE DURING THE EVENING. THIS FRONT
IS FORECAST TO PRODUCE A MODERATELY GUSTY EAST CANYON WIND IN THE
MIDDLE AND LOWER RIO GRANDE VALLEY FRIDAY AND FRIDAY NIGHT. ANOTHER
CROP OF THUNDERSTORMS IS EXPECTED ALONG AND EAST OF THE CONTINENTAL
DIVIDE ON SATURDAY AS MOISTURE RECYCLES...BUT THERE WILL BE A
DOWNTICK IN COVERAGE.
THE UPPER HIGH IS FORECAST TO MIGRATE SOUTHEASTWARD TO AROUND THE NM
BOOT HEEL ON SUNDAY...THEN TO THE SE OF NM ON MONDAY AS AN UPPER
LEVEL TROUGH DEEPENS INTO A LOW PRESSURE SYSTEM ON THE WEST COAST
AND EJECTS SOME OF ITS SHORTWAVE ENERGY INLAND ACROSS THE CENTRAL
ROCKIES. THERE ARE SIGNIFICANT DISAGREEMENTS BETWEEN MODELS ON THE
TRACK AND TIMING OF THIS LOW AND THE SHORTWAVES...BUT THE GFS AND
ECMWF DO AGREE FAIRLY WELL ON A TAP OF SUBTROPICAL MOISTURE IN
STRENGTHENING SW FLOW ALOFT REACHING SW AREAS SUNDAY AND MUCH OF
CENTRAL AND WESTERN NM MONDAY.
A ROLLER COASTER OF TEMPERATURES IS EXPECTED THROUGH THE WEEKEND.
HIGH TEMPERATURES WILL WARM A FEW TO 5 DEGREES THURSDAY...THEN FALL
WITH THE BACK DOOR COLD FRONT FRIDAY. FALLING TEMPERATURES WILL
CONTINUE IN THE WEST THROUGH SATURDAY...WHILE EASTERN READINGS BEGIN
TO REBOUND. HIGH TEMPS SHOULD THEN WARM SUNDAY AS THE CENTER OF HIGH
PRESSURE DRAWS NEAR...THEN BEGIN TO FALL IN THE WEST AGAIN MONDAY AS
BETTER MOISTURE ARRIVES. MINIMUM HUMIDITIES SHOULD FALL A FEW TO 22
PERCENT ON SUNDAY BEFORE BEGINNING TO REBOUND IN THE WEST ON MONDAY.
HIGH HAINES VALUES IN THE 5 TO 6 RANGE ARE EXPECTED OVER NORTHWEST
AND NORTH CENTRAL AREAS THURSDAY...THEN OVER NW AND WEST CENTRAL
AREAS FRIDAY. EXTREME VALUES SHOULD ABATE EAST OF THE CONTINENTAL
DIVIDE WITH THE ARRIVAL OF BETTER MOISTURE ON FRIDAY NIGHT AND
SATURDAY...ONLY TO OVERSPREAD MOST LOCATIONS ALONG AND NORTH OF
INTERSTATE 40 ON SUNDAY. NORTHEAST AREAS MAY CONTINUE TO BE
AFFLICTED WITH HIGH HAINES ON MONDAY.
POCKETS OF POOR VENTILATION WILL IMPACT WEST CENTRAL AREAS
WEDNESDAY...THEN NORTH CENTRAL...CENTRAL AND SOUTHWEST AREAS
THURSDAY. POCKETS OF POOR VENTILATION MAY LINGER INTO FRIDAY WEST
OF THE CONTINENTAL DIVIDE AND OVER THE SANGRE DE CRISTOS...BUT
VENTILATION LOOKS TO IMPROVE MOST PLACES SATURDAY AND ESPECIALLY
SUNDAY. RATES SHOULD THEN STAY GOOD TO EXCELLENT MONDAY. 44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
150 AM EDT THU SEP 10 2015
.SYNOPSIS...A SURFACE TROUGH WILL REMAIN OVER CENTRAL NORTH CAROLINA
THROUGH TONIGHT. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
THURSDAY AFTERNOON...BEFORE STALLING ACROSS THE AREA FRIDAY. A
STRONGER COLD FRONT AND UPPER LEVEL LOW WILL APPROACH FROM THE
NORTHWEST FRIDAY NIGHT AND SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 940 PM WEDNESDAY...
A WEAK PERTURBATION EVIDENT AT 700-500 MB IS NOW TRACKING ENE
THROUGH THE WRN CWA... BRINGING SCATTERED SHOWERS AND ISOLATED
BRIEFLY STRONG (BUT SUB-SEVERE) STORMS. THIS CONVECTION IS ALSO
BEING SUPPORTED BY WEAK LINGERING POST-SUNSET ELEVATED INSTABILITY.
DEEP MOIST FLOW PERSISTS WITH GULF AND ATLANTIC SOURCES...
CONTRIBUTING TO PW VALUES WELL ABOVE NORMAL... AROUND 2.0 INCHES.
THE LATEST HRRR AND HI-RES NMM CONTINUE TO TRACK THIS WAVE AND
ASSOCIATED CONVECTION NORTHEAST THROUGH THE CWA THROUGH ABOUT 08Z...
AND THE FORECAST UPDATE WILL REFLECT THIS TIMING AND PLACEMENT...
WITH CHANCE POPS (HIGHEST IN THE CENTRAL AND NE CWA... ALONG THE
SURFACE TROUGH) INTO THE EARLY OVERNIGHT HOURS BEFORE TAPERING
DOWNWARD AND DEPARTING. A SECOND WAVE NOW PUSHING THROUGH SE TN AND
INTO NW GA IS ALSO ON TRACK TO MOVE INTO THE WRN CWA LATE TONIGHT...
AND WHILE IT`S UNCLEAR IF THERE WILL BE ENOUGH ELEVATED INSTABILITY
TO SUSTAIN THIS ACTIVITY WITHIN A MARGINAL DEEP-LAYER SHEAR
ENVIRONMENT... WILL NEED TO LEAVE IN A MENTION OF AT LEAST ISOLATED
STORMS THROUGH THE NIGHT. OTHERWISE... EXPECT MOSTLY CLOUDY SKIES
WITH PLENTY OF CONVECTIVE DEBRIS CLOUDS AS WELL AS PATCHY STRATUS
LATE. LOWS OF 70-75. -GIH
ON THURSDAY...FOG/STRATUS WILL BURN OFF QUICKLY AFTER 10 AM AS
DAYTIME HEATING INCREASES...AND EXPECT LOW CLOUDS TO BECOME
SCATTERED BY LATE MORNING. HOWEVER...RAIN CHANCES WILL INCREASE
DURING EARLY AFTERNOON AS COLD FRONT APPROACHES FROM THE NORTHWEST.
BELIEVE THE MAIN CONCERN WILL BE LOCALLY HEAVY RAINFALL DUE TO DEEP
MOISTURE POOLING AHEAD OF THE FRONT...PUSHING PRECIPITABLE WATER
VALUES IN THE 1.8 TO 2 INCH RANGE FOR MUCH OF THE AREA.
OTHERWISE...LIGHT UPPER LEVEL WINDS AND ONLY MODEST INSTABILITY
SHOULD SUPPORT SCATTERED STORMS...MOST OF WHICH WILL REMAIN BELOW
SEVERE CRITERIA. AFTERNOON HIGH TEMPERATURES WILL RANGE FROM THE
MID/UPPER 80S NORTH TO THE LOW 90S SOUTH.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 330 PM WEDNESDAY...
SOMEWHAT UNSETTLED PATTERN INTO FRIDAY WITH WEAK SURFACE BOUNDARY
OVER EASTERN NORTH CAROLINA WITH WEAK UPPER LEVEL WAVE TRACKING
FROM THE WEST THURSDAY NIGHT INTO FRIDAY MORNING. MODEL
DISCREPANCIES IN TIMING AND STRENGTH OF THIS WAVE EXIST. WHILE
THERE WILL BE SOME TENDENCY FOR DECREASE IN SHWR/TSTM ACTIVITY
THURS NIGHT INTO FRIDAY WITH SURFACE BOUNDARY SHIFTING EAST...IT
REMAINS IN THE AREA AND WASHES OUT TO SOME DEGREE LATE FRIDAY AS
DEEPER UPPER TROUGH DIGS TO THE WEST. UPPER WAVE MAY HELP KEEP
SOME ACTIVITY GOING OVERNIGHT AND 12Z NAM WITH SLOWER TIMING WANTS
TO DEVELOP QUITE A BIT OF PRECIP DURING THE DAY FRIDAY ACROSS
SOUTHERN HALF OF FCST AREA WITH CIRCULATION EVIDENT AT THE
SURFACE. THINK THIS IS OVERDONE AND LEANING TOWARD FASTER AND
DRIER SOLUTIONS FROM 12Z GFS AND ECMWF. BEST CHANCES FOR LINGERING
PRECIP THURS NIGHT AND SOME CONVECTIVE DEVELOPMENT LATER FRIDAY
WILL BE ACROSS SOUTHERN AND EASTERN AREAS...CLOSER TO DECAYING
SURFACE BOUNDARY...BUT NOT GOING HIGHER THAN LOW CHC POPS AT THIS
TIME.
SOME TYPICAL NOCTURNAL DECREASE IN SHOWER ACTIVITY AGAIN ON FRIDAY
NIGHT BUT A FEW MODELS...MOST NOTABLY CANADIAN STILL INDICATE AN
UPPER WAVE AHEAD OF DIGGING TROUGH AND KEEPING SOMETHING GOING...SO
WILL NOT ELIMINATE POPS FRI NIGHT EITHER. THEN BEST CHANCES FOR
MORE WIDESPREAD SHWR/TSTM ACTIVITY WILL BE SATURDAY WITH DIGGING
TROUGH MOVING INTO WESTERN APPALACHIANS AND APPROACHING LOW-LEVEL
BAROCLINIC ZONE WITH INCREASING SW FLOW. LOOKS LIKE THIS NEW FRONTAL
BOUNDARY WILL BE PUSHING THROUGH CENTRAL NC LATE IN THE DAY SATURDAY
AND TIMED FAIRLY WELL WITH MAX HEATING...AND GIVEN SOME UPPER LEVEL
SUPPORT AND AT LEAST MARGINAL SHEAR...STILL LOOKS LIKE A CHANCE FOR
SOME STRONG TO SEVERE STORMS FOR LATE SATURDAY. LIMITED INSTABILITY
WITH LOTS OF CLOUD COVER MAY KEEP A MORE WIDESPREAD SEVERE EVENT
FROM OCCURRING...BUT WORTH KEEPING A CLOSE EYE ON.
HAVE HIGH CHC TO LOW LIKELY POPS SATURDAY...AND NOT GOING HIGHER
ONLY BECAUSE TIMING COULD SHIFT SLOWER INTO THE EVENING SINCE
DIGGING TROUGHS ARE SOMETIMES NOT HANDLED WELL BY MODELS. TRENDS
THOUGH HAVE ACTUALLY BEEN TO SPEED THIS UP A BIT AND FOR NOW HAVE
POPS QUICKLY LOWERING FOR SATURDAY EVENING. THIS MAY ALL NEED TO BE
ADJUSTED.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 PM WEDNESDAY...
DEEP UPPER TROUGH STILL APPEARS TO BE PROGRESSIVE ENOUGH SUCH
THAT SURFACE FRONT LIKELY TO BE EAST OF RAH FCST AREA BY SUNDAY
MORNING...ALONG WITH DEEPER CONVECTION AND HIGHER CHANCES FOR
PRECIP. 12Z GFS ESPECIALLY FAST WITH THIS. HOWEVER AS THE UPPER
TROUGH LIFTS NORTHEAST...COOLER TEMPS ALOFT WILL RESULT IN MID
LEVEL LAPSE RATES THAT COULD SUPPORT VERY SHALLOW CONVECTIVE
SHOWERS... VERY UNLIKELY TO BE ANY THUNDER...MAINLY FOR THE
NORTHERN AND EASTERN PORTIONS OF THE AREA. IF MORE PROGRESSIVE
TRENDS CONTINUE MAY EVENTUALLY DROP PRECIP CHANCES ALTOGETHER FOR
SUNDAY. MAIN STORY SUNDAY WILL BE MUCH COOLER AIR MASS AND WITH AN
ABUNDANCE OF CLOUDS HIGH TEMPS SHOULD BE AT LEAST 5F BELOW NORMAL.
70S FOR MOST LOCATIONS.
FOR THE EARLY PART OF NEXT WEEK THE UPPER TROUGH LIFTS WELL
NORTHEAST OVER NEW ENGLAND AND IS REPLACED BY A SHALLOW UPPER RIDGE
WITH AN ASSOCIATED LARGE AREA OF SURFACE HIGH PRESSURE. THIS WILL
KEEP DEEPER MOISTURE WELL TO THE SOUTH OF THE AREA WITH LOWER
HUMIDITIES AND COOL OVERNIGHTS BUT SLOWLY RECOVERING MAX TEMPS BACK
INTO THE LOWER 80S BY MID WEEK.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 147 AM THURSDAY...
24 HOUR TAF PERIOD: SHOWERS AND STORMS...ASSOCIATED WITH AN UPPER
LEVEL DISTURBANCE... ARE CONTINUING TO CROSS THE REGION WITH
ASSOCIATED SUB-VFR CONDITIONS MAINLY IMPACTING KFAY AND KRDU... AND
POTENTIALLY KRWI IN THE NEXT FEW HOURS. AFTER THAT... MORNING
STRATUS/FOG WILL LIKELY AFFECT MOST SITES AFTER 08Z... LIFTING IN
THE LATE MORNING HOURS. SHOWERS AND THUNDERSTORMS WITH POTENTIAL SUB-
VFR CONDITIONS WILL DEVELOP THURSDAY AFTERNOON AND EVENING AHEAD OF
AN APPROACHING COLD FRONT.
OUTLOOK: SHOWERS AND STORMS WILL BE POSSIBLE FRIDAY AND SATURDAY...
AHEAD OF A STRONG COLD FRONT THAT WILL CROSS THE REGION SATURDAY.
HIGH PRESSURE WILL MOVE IN TO THE AREA EARLY IN THE WEEK... BRINGING
A HIGH LIKELIHOOD OF VFR CONDITIONS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/RNK
SHORT TERM...RNK
LONG TERM...RNK
AVIATION...30
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1237 AM CDT THU SEP 10 2015
.UPDATE...
ISSUED AT 1237 AM CDT THU SEP 10 2015
CURRENT INHERITED FORECAST IS ON TRACK WITH ONLY A FEW MINOR
UPDATES NEEDED FOR THE EARLY MORNING FORECAST UPDATE.
UPPER LEVEL JET DYNAMICS AND SUBTLE EMBEDDED MID LEVEL IMPULSES
CONTRIBUTING TO BKN MID LEVEL CLOUDS ACROSS MONTANA AND MAINLY
CENTRAL AND SOUTHERN NORTH DAKOTA. A FEW WEAK RADAR RETURNS AS
WELL SO WILL MAINTAIN A SLIGHT CHANCE FOR A BRIEF/LIGHT SHOWER
ALONG THE PATH OF THE LEFT EXIT REGION OF A RATHER WEAK UPPER JET
STREAK PUSHING SOUTHEAST ACROSS THE REGION...WEST CENTRAL INTO MY
SOUTH CENTRAL AND SOUTHERN JAMES RIVER VALLEY AREAS.
TEMPERATURES NORTH CENTRAL SLOW TO DROP THOUGH WILL KEEP THE FROST
ADVISORY AS IS WITH A FEW MID 30S OVER SOUTHERN CANADA OBSERVED.
SKIES SHOULD CLEAR ACROSS MY FAR NORTH NEAR 12Z AS SURFACE HIGH
PRESSURE BUILDS SOUTH INTO THE NORTHERN PLAINS...SO STILL TIME FOR
TEMPS TO DROP.
UPDATE ISSUED AT 816 PM CDT WED SEP 9 2015
UPDATED THE POPS WITH THE HRRR MODEL WHICH SEEMED TO DEPICT SOME
OF THE RETURNS THE RADAR SHOWS. SO WENT WITH SLIGHT CHANCE OF
SHOWERS SOUTHWEST INTO THE SOUTH CENTRAL THIS EVENING.
UPDATE ISSUED AT 628 PM CDT WED SEP 9 2015
COLD FRONT WITH NO SIGNIFICANT WEATHER HAS MOVED THROUGH THE
STATE. SKIES WILL CLEAR ACROSS THE NORTH TONIGHT WHILE MORE CLOUDS
REMAIN ACROSS THE SOUTH. COOLEST TEMPERATURES OVERNIGHT ARE
FORECAST WHERE CLOUDS WILL BE CLEAR IN THE NORTH. THIS IS WHERE
THE FROST ADVISORY HAS BEEN ISSUED FOR TONIGHT. CURRENT FORECAST
TRENDING WELL WITH NO MAJOR CHANGES.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 305 PM CDT WED SEP 9 2015
FROST TONIGHT NORTH CENTRAL HIGHLIGHTS THE SHORT TERM FORECAST.
ISSUED A FROST ADVISORY FOR NORTH CENTRAL NORTH DAKOTA AND THE
TURTLE MOUNTAINS AREA FOR TONIGHT INTO THURSDAY MORNING AS COOL
SURFACE HIGH PRESSURE BUILDS IN. IT APPEARS THAT THESE
AFOREMENTIONED AREAS WILL REMAIN CLEAR THROUGH THE
NIGHT...REMAINING IN BETWEEN THE WRAP AROUND STRATUS FIELD IN
SOUTHERN CANADA AND THE MID LEVEL DECKS FORECAST TO REMAIN ACROSS
THE WEST AND SOUTH CENTRAL. THUS...DID UNDERCUT THE 12 UTC
GUIDANCE CONSENSUS FOR THESE AREAS WITH FORECAST LOWS IN THE MID
30S...IN LINE WITH WHAT OCCURRED ACROSS CANADA THIS MORNING IN A
SIMILAR SETUP. GIVEN CLOUD COVER...FORECAST LOWS IN THE 40S ARE
EXPECTED ELSEWHERE. HOWEVER...THIS WILL HAVE TO BE MONITORED. A
COOL THURSDAY IS FORECAST WITH HIGH PRESSURE REMAINING OVER THE
AREA WITH HIGHS IN THE 60S FOR ALL OF WESTERN AND CENTRAL NORTH
DAKOTA.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED SEP 9 2015
QUIET AND COOL INTO THE BEGINNING OF NEXT WEEK...THEN CHANCES OF
SHOWERS AND THUNDERSTORMS RETURN TO THE FORECAST.
THURSDAY NIGHT A COOL SURFACE HIGH SETTLES OVER THE EASTERN DAKOTAS
WITH CLEAR TO PARTLY CLOUDY SKIES AND LIGHT WINDS. EXPECT
RADIATIONAL COOLING WITH DEWPOINTS IN THE 30S TO ALLOW TEMPERATURES
TO DIP INTO THE MID 30S. AS A RESULT...PATCHY FROST IS FORECAST OVER
PARTS OF WESTERN AND CENTRAL NORTH DAKOTA LATE THURSDAY NIGHT INTO
EARLY FRIDAY MORNING.
THE WEST COAST RIDGE AMPLIFIES THROUGH THE NORTHERN ROCKIES WITH
MEAN RIDGING THROUGH NORTH DAKOTA BY THE END OF THE DAY FRIDAY. THIS
SPELLS A WARMING TREND THROUGH THE WEEKEND AFTER A COOL MORNING ON
FRIDAY.
BY MONDAY NIGHT THE REGION COMES UNDER SOUTHWEST MID LEVEL FLOW AND
INCREASED MOISTURE AND INSTABILITY...AS A PACIFIC NORTHWEST LONG
WAVE TROUGH DEEPENS AND BY MID WEEK CUTS OFF OVER THE SOUTHERN
CANADIAN PRAIRIE PROVINCES. THE BASE OF THE TROUGH LIFTS NORTHEAST
INTO THE DAKOTAS TUESDAY NIGHT INTO WEDNESDAY. THUS HAVE CHANCES FOR
THUNDERSTORMS MONDAY NIGHT THROUGH TUESDAY NIGHT AHEAD OF THE
SYSTEM...AND RAIN SHOWERS WEDNESDAY BEHIND THE SYSTEM.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1237 AM CDT THU SEP 10 2015
SURFACE HIGH PRESSURE ACROSS SOUTHERN CANADA WILL MOVE SOUTH INTO
THE NORTHERN PLAINS TONIGHT AND THURSDAY. VFR EXPECTED THROUGH THE
06Z TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 4 AM TO 9 AM CDT THIS MORNING FOR NDZ002>005-
011>013.
&&
$$
UPDATE...NH
SHORT TERM...AYD
LONG TERM...JV
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
102 AM EDT THU SEP 10 2015
.SYNOPSIS...
A COLD FRONT OVER NORTHERN OHIO WILL CONTINUE TO MOVE SOUTHEAST
AWAY FROM THE LOCAL AREA TONIGHT. THE FRONT IS EXPECTED TO
EVENTUALLY STALL NEAR THE OHIO RIVER ON THURSDAY MORNING. WEAK
HIGH PRESSURE WILL BUILD OVER THE REGION TOMORROW AND TOMORROW
NIGHT. ANOTHER COLD FRONT WILL FOLLOW ON FRIDAY WITH A POTENT
UPPER AIR DISTURBANCE EXPECTED TO IMPACT THE LOCAL AREA OVER THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A FEW LIGHT SHOWERS OR SPRINKLES CONTINUE TO APPEAR ON ILN RADAR
SO WILL LEAVE A LOW 20-30 POP IN OUR SOUTHERN COUNTIES FOR A FEW
MORE HOURS. THE DRY LOW LEVEL AIR IS EVIDENT BY THE LOSS OF LOW
CLOUDS WITH MAINLY JUST MID AND HIGH LEVEL CLOUD OVER THE AREA.
ANY PRECIPITATION REACHING THE GROUND OVERNIGHT WILL BE VERY LIGHT
AS IT FALLS OUT OF THE HIGHER CLOUD DECK. SLIGHTLY REDUCED CLOUD
COVER LATE TONIGHT INTO TOMORROW. WITH LESS CLOUD COVER...LOWERED
MINS BY A DEGREE OR SO IN NE OHIO.
PREVIOUS DISCUSSION...
AS FEARED...LITTLE PRECIP HAS DEVELOPED THIS AFTERNOON. SOME
SCATTERED SHOWERS REMAIN OVER THE EASTERN END OF THE AREA. MOST OF
THE GUIDANCE INCLUDING THE LATEST RUC AND HRRR SHOW THE
POSSIBILITY OF NEW DEVELOPMENT THROUGH EARLY EVENING FROM ABOUT
I-71 EAST. THIS SEEM PLAUSIBLE GIVEN THE SHOWERS OVER INDIANA AND
SW OHIO SO WILL KEEP A SMALL MENTION FOR A FEW HOURS. BY MIDNIGHT
ALL BUT THE SE END OF THE AREA SHOULD BE DRY. THE SURFACE FRONT
WILL EVENTUALLY STALL AND THE THREAT FOR SHOWERS ACROSS THE SE TIP
OF THE AREA COULD PERSIST INTO THURSDAY MORNING. THE NEAREST
CLEARING IS STILL BACK BY CHICAGO SO THAT WILL TAKE SOME TO REACH
THE LOCAL AREA AS WELL. DO THINK THAT THAT ABOUT THE NW 1/3 TO
1/2 OF THE AREA WILL BECOME PARTLY CLOUDY BY MORNING. THIS WILL
RESULT IN A DECENT TEMPERATURE GRADIENT ACROSS THE AREA WITH LOW
60S IN THE SE AND READINGS WELL DOWN INTO THE 50S IN THE NW.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
JUST MINOR ADJUSTMENTS TO THE SHORT TERM TODAY AS THE PREVIOUS
PACKAGE WAS ON THE RIGHT TRACK. THURSDAY AND THURSDAY NIGHT WILL
BE DRY. ANOTHER COLD FRONT IS STILL ON TRACK FOR FRIDAY. VERY
LITTLE IF ANY PRECIP IS EXPECTED BEFORE 12Z. WILL END UP GOING
WITH A FEW HOURS OF LIKELY MOST AREAS. UNFORTUNATELY THE BEST
WINDOW FOR PRECIP IN THE EAST WILL BE FRIDAY AFTERNOON AND
EVENING. THERE WILL BE A DISTINCT AIRMASS CHANGE BEHIND THIS FRONT
WITH THE UNSEASONABLY COOL AIR SETTLING OVER THE AREA OVER THE
WEEKEND. AS A RESULT...INSTABILITY SHOWERS HELPED ALONG BY LAKE
ERIE CAN BE EXPECTED BOTH SATURDAY AND SUNDAY. BY 12Z SUNDAY 500
MB TEMPS WILL BE ON THEIR WAY TO NEG 20 OR COLDER WHICH WILL GIVE
LAKE TO 500MB TEMP DIFFERENCES OF 45 DEGREES OR GREATER. THIS
MEANS THUNDER WILL BE A GOOD BET DOWNWIND OF THE LAKE AND HAVE
BUMPED PRECIP CHANCES TO LIKELY IN FAR NE OH AND NW PA FOR
SATURDAY NIGHT. HAVE CONTINUED THE RECENT TREND OF LOWERING HIGH
TEMPS OVER THE WEEKEND. THERE COULD BE A FEW AREAS THAT FAIL TO
GET OUT OF THE 50S FOR HIGHS ON SUNDAY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AN UPPER LEVEL LOW WILL BE MOVING OFF TO THE EAST ON SUNDAY WILL
BRING COLDER TEMPERATURES 10-15 DEGREES BELOW AVERAGE AND
NORTHWESTERLY FLOW TO NORTHERN OHIO AND NORTHEAST PA. THIS NORTHWEST
FLOW OFF OF LAKE ERIE...PLUS 850 MB TEMPERATURES OF 6-8C...AND WARM
LAKE WATER TEMPERATURES AROUND 70F (A TEMPERATURE DIFFERENCE OF
AROUND 25 DEGREES FAHRENHEIT) WILL ALLOW FOR SOME SIGNIFICANT
LAKE EFFECT RAIN TO DEVELOP OVER THE AREA ON SUNDAY INTO THE EARLY
PART OF MONDAY. IN SHORT...SUNDAY WILL BE MORE REPRESENTATIVE OF A
COLD AND RAINY NOVEMBER DAY THAN THE GLIMPSE OF JULY THAT WE HAD
OVER LABOR DAY WEEKEND.
LATE ON MONDAY...SOME UPPER LEVEL RIDGING WILL MOVE IN ALONG WITH A
SURFACE HIGH PRESSURE. WINDS WILL SHIFT TO COME FROM THE SOUTH AND
WILL WARM TEMPERATURES CLOSER TO CLIMO AND DRY THE AREA OUT FROM WET
WEATHER OVER THE WEEKEND. HIGH PRESSURE LOOKS TO BE IN PLACE THROUGH
A MAJORITY OF WEDNESDAY ALLOWING FOR A COUPLE OF DRY...TYPICAL MID-
SEPTEMBER DAYS IN NORTHERN OHIO AND NORTHWEST PA.
MODELS CURRENTLY DEPICT A COLD FRONT BEGINNING TO APPROACH THE AREA
BY THURSDAY MORNING...WHICH COULD BRING SOME WET WEATHER FOR THE END
OF NEXT WEEK. STILL A LITTLE FAR OUT TO TELL WHAT COULD HAPPEN WITH
THIS SYSTEM AS IT APPROACHES THE EASTERN GREAT LAKES.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/... A NARROW RIDGE OF HIGH
PRESSURE OVER LWR MI WILL MOVE SE INTO THE CWA THRU THE AFTERNOON
AND WEAKEN. DRIER AIR BEING PUSHED SOUTH WITH THE RIDGE SHOULD
SPREAD ACROSS THE AREA TO FLUSH OUT THE LOWER CLOUDS SO EXPECT ONLY
SCT CU WITH DAYTIME HEATING BY MIDDAY THU. MOISTURE POOLING AHEAD OF
THE NEXT COLD FRONT COULD START TO PRODUCE SOME CLOUDS FROM 6 TO 10K
FEET AFTER 00Z AT TOL.
OUTLOOK...NON VFR STARTING LATER FRIDAY AND CONTINUING THROUGH
THE WEEKEND...ESPECIALLY FOR NE OH AND NW PA.
&&
.MARINE...
HAVE CANCELED THE SMALL CRAFT ADVISORY. LATEST GUIDANCE
AND ANALYSIS OF CURRENT CONDITIONS LEADS TOWARD 2 TO OCCASIONALLY 4
FEET OVERNIGHT. THE GRADIENT IS NOT THAT TIGHT AND COLD AIR
ADVECTION NOT STRONG. NORTH FLOW COMES AROUND TO THE NORTHEAST THIS
EVENING AND WILL BE SITTING AT 10 TO 15 KNOTS SUSTAINED. HIGH
PRESSURE WILL STAY NORTH OF THE LAKE ON THURSDAY AND GET SQUEEZED
OUT BY AN APPROACHING COLD FRONT FROM THE NORTHWEST ON FRIDAY. THIS
FRONT WILL HAVE THE POTENTIAL TO CHURN UP THE LAKE WITH STRONG COLD
AIR ADVECTION COMMENCING FRIDAY NIGHT OR SATURDAY MORNING. SMALL
CRAFT ADVISORIES A POSSIBILITY THIS WEEKEND. UPPER LOW STAYS IN THE
VICINITY AND IT WILL BE A COOL AND SHOWERY WEEKEND. WINDS ARE NOT
TOO STRONG ALOFT AND WATERSPOUTS MAY BE POSSIBLE THIS WEEKEND TOO.
HIGH PRESSURE BUILDS ACROSS THE LOWER OHIO VALLEY MONDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA/KEC
SHORT TERM...KUBINA
LONG TERM...SEFCOVIC
AVIATION...ADAMS
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1153 PM CDT WED SEP 9 2015
.UPDATE...
UPDATED FOR THE 06Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 917 PM CDT WED SEP 9 2015/
DISCUSSION...
A WEAK 1012 MB SURFACE LOW IS SITUATED OVER WEST TN/NRN MS THIS
EVENING. BEST LIFT AND DEEPER MOISTURE IS PUSHING EAST INTO
MIDDLE TN. AREAL COVERAGE OF PRECIP IS RAPIDLY DIMINISHING WITH
JUST A FEW SHOWERS OVER PARTS OF WEST TN ATTM. CLEARING IS ALREADY
WORKING INTO PARTS OF NE AR. LATEST HRRR INDICATING THAT SHOWERS
AND THUNDERSTORMS MAY REDEVELOP ACROSS PARTS OF NORTH MS LATER
TONIGHT AS ANOTHER PIECE OF UPPER LEVEL ENERGY MOVES THROUGH. LEFT
LIKELY POPS WITH A MENTION OF THUNDER IN THAT AREA AFTER
MIDNIGHT. OTRW TENDED TO TRIM POPS AND ADDED A MENTION OF FOG
ESPECIALLY IN AREAS THAT WILL CLEAR OUT ACROSS NE AR.
SJM
PREV DISCUSSION... /ISSUED 237 PM CDT WED SEP 9 2015/
WIDESPREAD RAIN AND THUNDERSTORMS ARE ONGOING ACROSS MUCH OF THE
MIDSOUTH. FORTUNATELY THEY ARE SUB SEVERE...BUT WE HAVE ISSUED A
COUPLE OF FLASH FLOOD WARNINGS DUE TO LOCALLY HEAVY RAIN IN THE
MEMPHIS AND SURROUNDING METROPOLITAN AREAS. DOPPLER RADAR
ESTIMATES NEAR 4 INCHES OF RAIN HAS FALLEN IN THESE AREAS...WITH
ANOTHER ROUND OR TWO OF HEAVY RAIN POSSIBLE THIS AFTERNOON. ALL OF
THIS RAIN IS FALLING AS A COLD FRONT MOVES SLOWLY ACROSS THE
MIDSOUTH. ITS EXACT LOCATION IS MASKED BY RAIN COOLED AIR AND
OUTFLOW BOUNDARIES...BUT IT LOOKS TO HAVE SHIFTED SOUTH OF THE
INTERSTATE 40 CORRIDOR. TEMPERATURES RANGE FROM THE MIDDLE 80S IN
NORTHEAST MISSISSIPPI TO THE LOW 70S IN NORTHEAST ARKANSAS. THE
FRONT WILL CONTINUE TO SHIFT SLOWLY TO THE SOUTH TONIGHT...WITH
THUNDERSTORMS POSSIBLE MAINLY ALONG AND SOUTH OF THE FRONT...AND
LIGHTER RAIN SHOWERS TO THE NORTH.
TOMORROW WE MAY SEE BRIEF CLEARING...BUT A SECONDARY COLD FRONT IS
EXPECTED TO BRING MORE RAIN AND WEAK THUNDERSTORMS TO THE MIDSOUTH
TOMORROW EVENING...CONTINUING INTO FRIDAY. DEW POINTS AND
TEMPERATURES ARE NOT EXPECTED TO COOL SIGNIFICANTLY UNTIL AT LEAST
MIDDAY FRIDAY...SO UNTIL THEN THUNDERSTORMS WILL REMAIN A
POSSIBILITY. NONE ARE EXPECTED TO BE SEVERE. AS THE SECONDARY COLD
FRONT SHIFTS ACROSS THE MIDSOUTH FRIDAY...RAIN CHANCES WILL
DIMINISH QUICKLY AND WINDS WILL SHIFT FROM THE NORTH. PORTIONS OF
THE MIDSOUTH...ESPECIALLY EAST ARKANSAS AND WEST TENNESSEE MAY SEE
HIGH TEMPERATURES BEFORE NOON...WITH STEADY OR FALLING
TEMPERATURES DURING THE AFTERNOON.
OVER THE WEEKEND...EXPECT FALL LIKE CONDITIONS. AFTERNOON HIGHS
WILL BE IN THE LOW TO MIDDLE 70S ACROSS MOST OF THE MIDSOUTH UNDER
MOSTLY CLEAR SKIES. TEMPERATURES WILL TREND WARMER DURING THE
EARLY TO MIDDLE PART OF NEXT WEEK. HIGHS WILL BE BACK IN THE
MIDDLE TO UPPER 70S BY WEDNESDAY. NO SIGNIFICANT RAIN CHANCES ARE
EXPECTED TO RETURN TO THE MIDSOUTH UNTIL WEDNESDAY AT THE
EARLIEST.
30
&&
.AVIATION...
06Z TAF CYCLE
SCATTERED RAIN SHOWERS REMAIN OVER FAR EASTERN SECTIONS OF THE
FORECAST AREA LATE THIS EVENING AND THIS WILL CONTINUE TO MOVE
EAST AND OUT OF THE FORECAST AREA OVERNIGHT. CURRENT VFR
CONDITIONS OVER WESTERN SECTIONS OF THE FORECAST AREA SHOULD END
OVERNIGHT AS LOW CLOUDS RETURN. SOME FOG IS EXPECTED TO DEVELOP
OVERNIGHT OVER MOST OF THE FORECAST AREA. SOME SCATTERED SHOWERS
MAY DEVELOP ACROSS THE REGION THURSDAY MORNING BUT END BY THE
AFTERNOON AS VFR CONDITIONS RETURN. WINDS WILL BE MAINLY FROM THE
NORTHWEST AT 4 TO 8 KNOTS FOR MOST OF THE FORECAST PERIOD.
ARS
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
425 AM CDT THU SEP 10 2015
.SHORT TERM (TODAY THROUGH FRIDAY)...GOES SOUNDER IMAGE OF
PRECIPITABLE WATER SHOWS A VERY MOIST AIR MASS IN PLACE ACROSS
THE REGION WITH PWAT VALUES BETWEEN 2.3 AND 2.5 INCHES. WATER
VAPOR IMAGERY SHOWS THE TAIL END OF A SHORT WAVE TROUGH FROM
EAST TEXAS EXTENDING WEST INTO CENTRAL TEXAS THIS MORNING.
THIS SHORT WAVE TROUGH WILL MOVE SOUTHEAST TOWARD THE UPPER
TEXAS COAST TODAY. A MODEST UPPER LEVEL JET STREAK IS ROUNDING
THE UPPER RIDGE TO THE WEST AND NOSING DOWN INTO THE HILL
COUNTRY. SCATTERED CONVECTION HAS FORMED NORTH OF COTULLA
EARLY THIS MORNING NEAR THIS UPPER JET FEATURE. THE LATEST
TECH WRF...OOZ NSSL WRF AND 05Z HRRR SHOW THIS ACTIVITY WILL
DIMINISH LATER THIS MORNING WITH ADDITIONAL CONVECTION FORMING
NEAR LOW LEVEL CONVERGENCE ZONE ALONG THE COAST. THE NOSE OF
THE UPPER JET WILL BE OVER THE VICTORIA CROSSROADS TO THE
COASTAL BEND TODAY. SO KEPT LIKELY POPS IN THIS REGION FOR
TODAY WITH CHANCE POPS OVER THE BRUSH COUNTRY. CONVECTION MAY
LINGER OVER THE BRUSH COUNTRY THIS EVENING AS BOUNDARY
INTERACTIONS KEEP ACTIVITY GOING FOR A FEW HOURS AFTER LOSS
OF HEATING. THERE SHOULD BE A BRIEF LULL IN ACTIVITY LATE THIS
EVENING...BUT ANOTHER SHORT WAVE TROUGH WILL BE APPROACHING THE
AREA FROM THE NORTHWEST AFTER MIDNIGHT. MODELS SUGGEST SCATTERED
CONVECTION WILL FORM OVERNIGHT AHEAD OF THIS FEATURE. THE UPPER
LEVEL JET STREAK MOVES TOWARD SOUTHEAST TEXAS ON FRIDAY WITH
WEAKLY DIFLUENT UPPER FLOW OVER THE REGION. WITH DEEP MOISTURE
REMAINING OVER SOUTH TEXAS...LOOKS LIKE MOST OF THE AREA WILL HAVE
A GOOD CHANCE TO SEE ADDITIONAL RAINFALL FROM SCATTERED TO
NUMEROUS CONVECTION FRIDAY. WENT LIKELY POPS FOR ENTIRE AREA ON
FRIDAY WITH MAX TEMPERATURES IN THE UPPER 80S EAST TO LOWER 90S
WEST.
&&
.LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...MOISTURE FROM WEAK
SURFACE BOUNDARY WILL BE SINKING INTO DEEP SOUTH TEXAS AT THE
BEGINNING OF LONG TERM PERIOD. HAVE CHANCE TO LIKELY POPS REMAINING
FRIDAY NIGHT...THEN DECREASING ON SATURDAY. DRIER CONDITIONS ARE
EXPECTED FOR SUNDAY AS HIGH PRESSURE RIDGE BRIEFLY BUILDS ACROSS THE
REGION. EARLY NEXT WEEK MOISTURE RETURNS TO THE AREA AS A COASTAL
TROUGH DEVELOPS IN ALONG THE GULF COAST. MODELS DIFFER SIGNIFICANTLY
ON THE DETAILS OF THIS TROUGH...BUT BOTH GFS AND ECMWF INDICATE
INCREASING CHANCES FOR SHOWERS AND STORMS TUESDAY AND WEDNESDAY.
THERE IS SOME TREND TO KEEP THE MAJORITY OF THE RAINFALL IN THE
MARINE AREAS...BUT WILL HOLD ONTO CHANCE POPS IN THE COASTAL BEND
AND BRUSH COUNTRY TEMPERATURES SHOULD BE SLIGHTLY BELOW NORMAL OVER
THE WEEKEND AND INTO EARLY NEXT WEEK...THEN GRADUALLY WARM BACK TO
NEAR NORMAL BY WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 92 77 89 74 88 / 60 40 60 50 40
VICTORIA 90 74 88 71 86 / 60 40 60 30 20
LAREDO 99 78 93 73 89 / 40 40 60 50 40
ALICE 94 75 91 72 89 / 60 40 60 50 40
ROCKPORT 90 78 88 74 87 / 60 50 60 50 40
COTULLA 95 75 91 72 91 / 50 40 60 30 20
KINGSVILLE 93 76 90 73 88 / 60 40 60 50 40
NAVY CORPUS 90 79 87 75 86 / 60 50 60 50 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TMT/89...SHORT TERM
PZ/83...LONG TERM
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
422 AM CDT THU SEP 10 2015
.SHORT TERM /NOW THROUGH FRIDAY/...LATEST WATER VAPOR SATELLITE
IMAGERY SHOWS A 500MB RIDGE CENTERED OVER WEST TEXAS INTO NORTHERN
MEXICO AND OVER SOUTH FLORIDA WITH 500MB WEAKNESS OVER THE WESTERN
GULF OF MEXICO. BROWNSVILLE RADAR SHOWS ISOLATED ACTIVITY ACROSS THE
LOWER TEXAS GULF WATERS THIS MORNING. THE LATEST HRRR SUGGESTS
CONVECTION WILL INCREASE ACROSS THE GULF WATERS THROUGH SUNRISE. BRO
SOUNDING FROM WEDNESDAY EVENING INDICATES PRECIPITABLE WATER VALUES
OF 1.87 INCHES. EXCEPT FOR SOME PASSING HIGH CLOUDS...MOSTLY CLEAR
SKIES AND LIGHT WINDS PREVAIL ACROSS DEEP SOUTH TEXAS EARLY THIS
MORNING. A LITTLE GROUND FOG MAY DEVELOP AROUND SUNRISE BEFORE
QUICKLY DISSIPATING. NOTE...THE SURFACE OBSERVATION FROM EDINBURG IS
NOT REPRESENTATIVE TO CURRENT WEATHER CONDITIONS.
THE MAIN FORECAST ISSUE WILL BE THE RAIN CHANCES ACROSS DEEP SOUTH
TEXAS THROUGH THE FORECAST PERIOD. DEEP TROPICAL MOISTURE
/PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES/ COMBINED WITH DAY
TIME HEATING WILL SUPPORT ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS TODAY. HIGH TEMPERATURES TODAY WILL RANGE FROM THE
LOWER 90S NEAR THE COAST TO THE UPPER 90S ACROSS THE UPPER VALLEY.
RAIN CHANCES MAY LINGER ACROSS THE NORTHERN RANCHLANDS TONIGHT AS
THE GFS SUGGESTS. OTHERWISE...MOSTLY CLOUDY SKIES WITH LOW
TEMPERATURES GENERALLY IN THE MID TO UPPER 70S. THE HIGHEST RAIN
CHANCES WILL BE FRIDAY WITH PRECIPITABLE WATERS BETWEEN 2.2 TO 2.5
INCHES PER THE LATEST NAM/GFS. HIGH TEMPERATURES FRIDAY WILL BE A
FEW DEGREES LOWER DUE TO THE INCREASE IN RAIN CHANCES AND CLOUD
COVER.
ANY OF THE HEAVIER OR SLOWER-MOVING SHOWERS AND THUNDERSTORMS TODAY
AND FRIDAY WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL
WITH NUISANCE FLOODING ON ROADS AND IN LOW-LYING AREAS...ESPECIALLY
THOSE WITH A HISTORY OF FLOODING.
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...ACTIVE WEATHER
PATTERN REMAINS FOR THE LONG TERM PORTION OF THE FORECAST. WEAK
COLD FRONT PASSES THROUGH THE BRO CWFA FRIDAY NIGHT...WITH
INVERTED SURFACE TROUGHINESS FORMING AND PERSISTING ALONG THE
LOWER TEXAS COAST AFTERWARDS. SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ARE FORECAST FOR FRIDAY NIGHT THROUGH SUNDAY...
WITH LOCALLY HEAVY RAINFALL POSSIBLE FRIDAY NIGHT AND SATURDAY
WITH DEEP TROPICAL MOISTURE IN PLACE. CONVECTION WILL BECOME MORE
ISOLATED SUNDAY NIGHT THROUGH THE END OF THE FORECAST AS THE FOCUS
OF THE ACTIVITY SHIFTS MORE OFFSHORE WITH WEAK LOW PRESSURE
POSSIBLY ATTEMPTING TO FORM OVER THE WESTERN GULF OF MEXICO.
TEMPERATURES WILL BE TEMPERED EARLY IN THE FORECAST PERIOD
COURTESY OF THE INCREASED CLOUDINESS AND OPPORTUNITIES FOR
RAINFALL...BUT SHOULD WARM UP TOWARDS THE MIDDLE AND END OF THE
FORECAST WITH LESSER CHANCES OF RAIN IN PLACE.
&&
.MARINE...NOW THROUGH FRIDAY...BUOY DATA AND OBSERVATION PLATFORMS
ALONG THE LOWER TEXAS COAST THIS MORNING INDICATE SOUTH WINDS BETWEEN
8 TO 13 KNOTS WITH SEA HEIGHTS NEAR 3 FEET ON THE GULF WATERS. A
WEAK PRESSURE GRADIENT ALONG THE LOWER TEXAS COAST WILL MAINTAIN
LIGHT TO MODERATE SOUTH TO SOUTHEAST WINDS AND LOW TO MODERATE
SEAS. HOWEVER...SMALL CRAFT WILL NEED TO EXERCISE CAUTION ON THE
LAGUNA MADRE THIS AFTERNOON DUE TO A SLIGHTLY STRONGER WINDS.
FRIDAY NIGHT THROUGH WEDNESDAY...LIGHT TO MODERATE WINDS AND LOW
TO MODERATE SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST THROUGH
EARLY NEXT WEEK AS A WEAK COLD FRONT PASSES THROUGH FRIDAY NIGHT
AND WEAK LOW PRESSURE PERSISTS AFTERWARDS. MARINE CONDITIONS NEAR
THE END OF THE FORECAST PERIOD ARE DEPENDENT ON THE DEVELOPMENT...
IF ANY...OF A WEAK AREA OF LOW PRESSURE OVER THE WESTERN GULF OF
MEXICO.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 92 80 91 75 / 20 20 40 60
BROWNSVILLE 93 79 91 74 / 20 20 40 60
HARLINGEN 95 78 93 72 / 30 20 50 60
MCALLEN 97 80 94 76 / 20 10 40 60
RIO GRANDE CITY 99 79 95 73 / 30 20 50 60
SOUTH PADRE ISLAND 87 82 85 76 / 20 20 40 60
&&
.BRO WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
SHORT TERM...CACERES-63
LONG TERM...TOMASELLI-66
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1148 PM CDT WED SEP 9 2015
.UPDATE...
ISSUED AT 908 PM CDT WED SEP 9 2015
TOUGH LITTLE FORECAST OVERNIGHT WITH MARGINAL INSTABILITY TO THE
WEST MOVING INTO THE AREA..WITH SOME WEAK FORCING. SURFACE LOW
AND FRONT ARE STILL WELL WEST NEAR KABR SOUTH DAKOTA...WITH ABOUT
500-1000 J/KG OF MUCAPE FROM KSUX-KSTC ROUGHLY...AND 250 J/KG HAS
FINALLY SHIFTED INTO THE WESTERNMOST MOST FORECAST AREA. THIS
AXIS REPRESENTS THE STORM ACTIVITY AT 02Z. SO FAR...SHOWER
ACTIVITY HAS DIED AS IT HEADS EAST OUT OF THE MOISTURE AXIS. GOES
WATER VAPOR SHOWING A FEW LITTLE WAVES ACROSS SOUTHERN MN...BUT A
MORE IMPRESSIVE SHORTWAVE TROUGH IN WESTERN SD...BOLTING FOR NERN
IA BY SUNRISE.
THE WESTERN SD WAVE WILL BE THE ONE TO SHIFT THE SURFACE LOW AND
FRONT SEWRD OVERNIGHT AND MOISTURE ALOFT WILL INCREASE ON
ISENTROPIC LIFT ACROSS IA/MN...INTO WI.
OVERALL THE IDEA IS THAT LIFT AND LOW-LEVEL CONVERGENCE AND SOME
850 MB MOISTURE TRANSPORT WILL INCREASE OVERNIGHT AS THE FRONT
MOVES THROUGH AND A BIT OF MUCAPE ARRIVES. A BIT MORE FOCUS
ARRIVES LATER FROM NORTHEAST IA INTO CENTRAL WI AS CONVERGENCE
INCREASES ALONG THE FRONT...AND 850MB MOISTURE TRANSPORT
INCREASES. HAVE INCREASED THE LATE NIGHT RAIN CHANCES FOR THIS
DEVELOPMENT.
BY SUNRISE THE VIGOROUS WESTERN SD TROUGH ARRIVES AND HAVE BUMPED
RAIN CHANCES UP ACROSS SERN MN AND NERN IA MAINLY.
OVERALL LIGHTNING THREAT IS VERY ISOLATED WITH LIMITED CAPE.
&&
.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 208 PM CDT WED SEP 9 2015
BIG PICTURE WATER VAPOR IMAGERY/RAP ANALYSIS SHOWING A CLOSED UPPER
LOW OVER WESTERN ONTARIO WITH A BROAD TROUGH OVER THE
NORTHER/CENTRAL CONUS. AN EMBEDDED MID-LEVEL SHORTWAVE TROUGH WAS
PUSHING INTO MN/DAKOTAS. RADAR MOSAIC SHOWING SCATTERED BAND OF
SHOWERS AND THUNDERSTORMS AHEAD OF THIS WAVE EXTENDING FROM
NORTHWEST WI/EAST CENTRAL MN TO SOUTH CENTRAL MN...MOVING EAST AT 35-
40KT. OTHERWISE...TEMPERATURES AS OF 2 PM RANGED FROM NEAR 70 ACROSS
NORTH CENTRAL WI...TO THE 75-80 DEGREE RANGE ALONG AND SOUTH OF I-90.
FOR THIS EVENING OVERNIGHT...WILL BE WATCHING THE WAVE CONTINUE
MOVING EAST ACROSS OUR AREA. RAP DEPICTING INCREASING 850-700MB
MOISTURE TRANSPORT ALONG WITH INCREASING MUCAPE...HIGHER 500-1000
J/KG SOUTH OF I-90. THEREFORE CARRIED SHRA/TS ALONG AND SOUTH OF I-
90 WITH ISOLATED THUNDER NORTH. MOST MESO MODELS DEPICTING SCATTERED
NATURE TO THIS CONVECTION...SO MAINTAINED 30-50 POPS FOR NOW.
ANOTHER STRONGER MID-LEVEL WAVE/DECENT 500-300MB PV-ADVECTION PUSHES
IN ACROSS THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER
VALLEY BY TOMORROW MORNING AND IS EXPECTED TO REINFORCE
SHOWER/THUNDER CHANCES ACROSS THE AREA. WITH EXPECTED SCATTERED
CONVECTION AND CLOUD COVER...WILL SEE COOLER TEMPERATURES WITH HIGHS
ACROSS NORTH CENTRAL WI ONLY IN THE 65-70 DEGREE RANGE AND LOW-MID
70S SOUTH OF I-90.
LOOKS LIKE SHOWER/ISOLATED THUNDER CHANCES PUSH OUT OF THE AREA BY
LATER THURSDAY EVENING WITH CLEARING SKIES THROUGH THE OVERNIGHT
HOURS. WITH DEEPENING MID/UPPER LEVEL TROUGH OVERHEAD AND RATHER
COLD 850MB TEMPS DROPPING INTO THE 1-5C RANGE...WILL SEE OVERNIGHT
LOWS DIP INTO THE 40S MOST LOCATIONS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 208 PM CDT WED SEP 9 2015
FOR FRIDAY THROUGH SATURDAY NIGHT...
ANOTHER EMBEDDED SHORTWAVE TROUGH COMES DOWN ACROSS THE AREA ON
FRIDAY. STEEP LOW TO MID-LEVEL LAPSE RATES EXPECTED TO GENERATE
QUITE A BIT OF CUMULUS AND SCATTERED SHOWERS...MAINLY ALONG AND EAST
OF THE MISSISSIPPI RIVER. OTHERWISE...A RATHER CHILLY AUTUMN-LIKE
DAY ON TAP AS HIGHS ONLY TOP OFF IN THE UPPER 50S TO THE MIDDLE 60S.
CHILLY DAY FRIDAY AND CLEARING SKIES FRIDAY NIGHT AS SURFACE HIGHS
SETTLES IN WILL SET THE STAGE FOR COLD TEMPERATURES FRIDAY NIGHT
WITH LOWS DIPPING INTO TO THE UPPER 30S/AROUND 40 ACROSS NORTH
CENTRAL WI...TO THE LOWER/MIDDLE 40S ELSEWHERE.
MODELS SHOW THE MID-LEVEL TROUGH PUSHING INTO THE EASTERN GREAT
LAKES/OHIO RIVER VALLEY SATURDAY AS MID-LEVEL RIDGE BUILD INTO OUR
REGION. THIS WILL PROVIDE DRY AND SLIGHTLY WARMER //BUT STILL WELL
BELOW NORMAL// TEMPERATURES IN THE LOW-MID 60S UNDER MOSTLY SUNNY
SKIES.
PLAN ON ANOTHER CLEAR AND COLD SATURDAY NIGHT WITH SURFACE HIGH
OVERHEAD. LOOKS TO BE AN IDEAL RIVER VALLEY/BOG AREA FOG NIGHT WITH
OVERNIGHT LOWS DIPPING INTO THE 40S ONCE AGAIN. DID NOT INCLUDE IN
THE WEATHER GRIDS FOR NOW AS EXACT RIDGE LOCATION COULD CHANGE A
BIT...BUT SOMETHING TO KEEP AN EYE ON NONETHELESS.
FOR SUNDAY THROUGH WEDNESDAY...DAYS 4 TO 7...
GFS AND ECMWF IN AGREEMENT ON A WARMING TREND FOR THIS PERIOD AS LOW
PRESSURE LIFT ACROSS THE NORTHERN PLAINS INTO CANADA. THIS PUTS US
IN WARM SECTOR WITH BROAD-SCALE LIFT ACROSS OUR AREA FOR A CHANCE OF
SHOWERS AND THUNDERSTORMS MAINLY IN THE TUESDAY NIGHT THROUGH
WEDNESDAY TIME FRAME. LOOKS LIKE HIGHS ON SUNDAY IN THE 65-70 DEGREE
RANGE...WARMING BACK INTO THE 70S...OR NEAR SEASONAL NORMALS...BY
WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1148 PM CDT WED SEP 9 2015
PERIOD OF WEATHER MOVING THROUGH KLSE SHOULD QUICKLY SHIFT EAST.
INSTABILITY STILL IS MOVING ACROSS THE AIRFIELDS OVERNIGHT AND
ANOTHER WEATHER IMPULSE IS MOVING INTO THE AREA BY SUNRISE. SOME
SHRA/TSRA COULD FORM FROM THAT SYSTEM...BUT IT APPEARS IT SHOULD
TRAVEL SOUTH OF THE AIRFIELDS. GENERALLY A VFR FORECAST IS
EXPECTED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BAUMGARDT
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS ALBANY NY
1025 AM EDT THU SEP 10 2015
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL MOVE ALONG A COLD FRONT THAT
HAS STALLED SOUTH OF THE REGION THIS AFTERNOON AND TONIGHT. THIS
WILL BRING SHOWERS TO THE REGION...WITH A SOAKING RAINFALL LIKELY
FROM THE CAPITAL REGION AND POINTS SOUTH AND EAST THIS AFTERNOON AND
TONIGHT. THE LOW WILL MOVE OFF THE NEW ENGLAND COAST FRIDAY...WITH
SHOWERS ENDING EARLY. ANOTHER STORM SYSTEM SHOULD BRING SHOWERS TO
THE REGION LATE SATURDAY INTO SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1025 AM EDT...THE RAP GUIDANCE WITH THE IR SATELLITE
PICTURE OVERLAYED SHOWS LOW PRESSURE ORGANIZING NEAR THE DELMARVA
REGION THIS MORNING. THE HEAVIEST SHOWERS AND THUNDERSTORMS REMAIN
WELL SOUTH AND EAST OF THE AREA NEAR LONG ISLAND AND EXTREME SE
NEW ENGLAND AND CAPE COD. SOME OVER RUNNING MOISTURE CONTINUES TO
MOVE N/NE FROM CNTRL PA/CNTRL NY IN THE NRN CATSKILLS...CAPITAL
REGION AND SRN VT. WE HAVE RETOOLED THE POPS BASED ON THE LOCAL
AND REGIONAL RADAR TRENDS AS THE SHORT-WAVE APPROACHES FROM THE OH
VALLEY WHICH WILL ENHANCE THE SHOWERS WITH THE WAVE DEVELOPING.
ALSO...A STRONG UPPER LEVEL JET MAX WILL BE TRANSLATING NORTHEAST
ACROSS EASTERN QUEBEC...WITH OUR REGION WITHIN THE RIGHT ENTRANCE
REGION. THE AGEOSTROPHIC RESPONSE TO THIS FEATURE WILL ALLOW
DIVERGENCE AND MID LEVEL FRONTOGENETIC FORCING TO INCREASE ACROSS
THE REGION LATE THIS MORNING AND ESPECIALLY THIS AFTERNOON AND
EVENING...ALLOWING SHOWERS OR EVEN A STEADY RAIN SHIELD TO DEVELOP
AND ADVANCE NORTH NORTHEAST FROM THE MID ATLANTIC STATES.
SO...INCREASING CHANCES FOR SHOWERS OR STEADY RAIN THIS AFTERNOON
FROM SOUTH TO NORTH...WITH THE STEADIEST RAIN MAINLY REMAINING
NEAR AND SOUTH AND EAST OF THE I-90/I-88 CORRIDORS. IT MAY TAKE
UNTIL LATE AFTERNOON OR CLOSER TO SUNSET FOR THIS RAIN TO REACH
THE LAKE GEORGE/GLENS FALLS AREA...AS WELL AS THE SOUTHWEST
ADIRONDACKS...WHICH MAY ESCAPE MUCH OF THE STEADIER RAIN.
ACROSS THE SOUTHEAST CATSKILLS...MID HUDSON VALLEY...NW CT AND SW
MA...DEEPER MOISTURE AND SOME ELEVATED INSTABILITY MAY ALLOW FOR
SOME EMBEDDED CONVECTIVE ELEMENTS TO DEVELOP THIS AFTERNOON WHICH
COULD PRODUCE LOCALLY HEAVY DOWNPOURS. SOME RUMBLES OF THUNDER
WILL BE POSSIBLE IN THESE AREAS LATER TODAY. WE REDUCED THE
THE AREA FOR A SLIGHT CHC OF THUNDER TO ONLY LOCATIONS SOUTH OF
THE CAPITAL REGION PRIOR TO 8 PM DUE TO A MORE STABLE ENVIRONMENT
BASED ON THE 12Z KALY SOUNDING. THIS IS ROUGHLY FROM THE SRN
BERKS...COLUMBIA AND GREENE COUNTIES SOUTH.
IT WILL BE MUCH COOLER REGIONWIDE COMPARED TO RECENT DAYS...WITH
MAX TEMPS MAINLY REACHING THE LOWER TO MID 70S IN VALLEYS...AND
MID 60S TO LOWER 70S ACROSS HIGHER TERRAIN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
TONIGHT...THE AFOREMENTIONED UPPER LEVEL DYNAMICS AND FORCING FROM
THE FRONTAL WAVE TO OUR SOUTHEAST...AND UPPER LEVEL JET TO OUR
NORTH SHOULD BE MAXIMIZED ACROSS THE REGION BEFORE
MIDNIGHT...LEADING TO THE BEST CHANCES FOR RAIN. FAR NW PORTIONS
OF THE REGION...SUCH AS NORTHERN HERKIMER AND HAMILTON COS MAY
JUST ESCAPE MUCH OF THIS RAIN. THE HEAVIEST RAIN SHOULD CONTINUE
TO BE AREAS SOUTH AND EAST OF THE GREATER CAPITAL REGION...WHERE
SOME RUMBLES OF THUNDER WILL REMAIN POSSIBLE THROUGH MIDNIGHT.
EVENTUALLY...AS THE WAVE PASSES FURTHER EAST...AND THE UPPER LEVEL
DYNAMICS WEAKEN...WE EXPECT THE RAIN TO TAPER OFF FROM W TO E
ACROSS THE REGION AFTER MIDNIGHT. SOME SHOWERS OR PATCHY DRIZZLE
SHOULD LINGER THROUGH OR AFTER DAYBREAK FOR AREAS NEAR AND ESP
EAST OF THE HUDSON RIVER. MIN TEMPS TONIGHT SHOULD FALL INTO THE
MID 50S TO LOWER 60S.
FRIDAY...SOME SPOTTY SHOWERS OR DRIZZLE MAY CONTINUE ACROSS
PORTIONS OF THE EASTERN CATSKILLS...CAPITAL REGION...SOUTHERN
VT...THE BERKSHIRES AND NW CT IN THE MORNING...BEFORE TAPERING
OFF BY EARLY AFTERNOON. ELSEWHERE...THE RAIN SHOULD HAVE ENDED BY
DAYBREAK. CLOUDS MAY BE TOUGH TO ERODE GIVEN THE MOIST BOUNDARY
LAYER...BUT SOME CLEARING IS EXPECTED TO DEVELOP IN THE AFTERNOON.
MAX TEMPS SHOULD REACH THE MID/UPPER 70S IN LOWER
ELEVATIONS...WITH MAINLY 60S TO LOWER 70S ACROSS HIGHER TERRAIN.
FRI NT...GENERALLY DRY WEATHER AND COOL...WITH MIN TEMPS FALLING
INTO THE 50S IN MANY AREAS. SOME 40S WILL BE POSSIBLE ACROSS
PORTIONS OF THE SOUTHERN ADIRONDACKS...AND ALSO HIGHER TERRAIN IN
SOUTHERN VT AND WESTERN MA.
SAT-SAT NT...A RATHER DYNAMIC UPPER LEVEL SYSTEM WILL BE
DEVELOPING ACROSS THE LOWER GREAT LAKES/OHIO VALLEY REGION DURING
THIS TIME...ALLOWING A SFC LOW TO DEVELOP ACROSS THE NORTHERN
APPALACHIANS...WITH A SECONDARY LOW POSSIBLY DEVELOPING NEAR THE
DELMARVA PENINSULA. INCREASING ISENTROPIC LIFT SHOULD ALLOW
SHOWERS TO DEVELOP AND TRANSLATE EASTWARD SAT AFTERNOON AND
NIGHT. IT IS POSSIBLE THAT THE RAIN IS SLOW TO DEVELOP ACROSS
EASTERN AREAS...AS THE BEST FORCING MAY REMAIN TO THE WEST AND
SOUTH THROUGH MUCH OF SAT. SO...INDICATING SLOWLY INCREASING POPS
FROM W TO E SAT...IN THE CHC RANGE...THEN LIKELY POPS FOR SAT NT.
SOME EMBEDDED THUNDERSTORMS COULD OCCUR SAT NT AS SHOWALTER
INDICES ARE FORECAST TO DROP BELOW ZERO...IN COMBINATION WITH
STRONG DYNAMICAL LIFT. MAX TEMPS SAT SHOULD REACH THE MID TO UPPER
70S IN VALLEYS...AND 60S ACROSS HIGHER TERRAIN. HOWEVER...SHOULD
RAIN DEVELOP SOONER...MUCH COOLER MAX TEMPS WOULD BE POSSIBLE. SAT
NT/SUN AM MINS SHOULD FALL INTO THE 50S TO LOWER 60S.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE LONG TERM PERIOD LOOKS TO START UNSETTLED AS A COMPLEX LOW
PRESSURE SYSTEM LIFTS THROUGH THE NORTHEAST ON SUNDAY INTO MONDAY.
WHILE MODELS ARE IN FAIRLY GOOD AGREEMENT WITH A LONG WAVE TROUGH
OVER THE EASTERN UNITED STATES...THEY DIFFER IN LOCATION OF BOTH THE
UPPER CLOSED LOW AND SURFACE LOW PRESSURE SYSTEMS. THE ECMWF IS
FARTHER NORTH THAN THE GFS WITH BOTH THE UPPER CLOSED LOW AND
SURFACE LOW PRESSURE SYSTEMS AND AS A RESULT HAS THE PCPN LIFTING
NORTH AND EAST OF FA QUICKER THAN THE GFS WHICH LINGERS PCPN INTO
MONDAY EVENING. FOR NOW WILL KEEP PCPN ACRS MUCH OF FA THROUGH
MONDAY WITH IMPROVING CONDITIONS MONDAY NIGHT. QPF AMOUNTS LOOK TO
BE BETWEEN A THIRD OF AN INCH AND AN INCH FOR SUNDAY AND SUNDAY
NIGHT. EXPECT RELATIVELY COOL CONDITIONS SUNDAY THROUGH MONDAY GIVEN
CLOUD COVER AND PCPN. HIGHS ON SUNDAY ARE EXPECTED TO BE IN THE MID
60S TO LOWER 70S WITH LOWS SUNDAY NIGHT IN THE UPPER 40S TO UPPER
50S AND HIGHS ON MONDAY IN THE UPPER 50S TO LOWER 70S.
IMPROVING CONDITIONS ARE EXPECTED FOR THE REMAINDER OF THE LONG TERM
PERIOD FROM MONDAY NIGHT THROUGH WEDNESDAY AS A LARGE RIDGE OF HIGH
PRESSURE BUILDS NORTHEAST FROM THE CENTRAL APPALACHIANS MONDAY NIGHT
INTO THE NORTHEAST TUESDAY NIGHT INTO WEDNESDAY. LOWS MONDAY NIGHT
ARE EXPECTED TO BE IN THE MID 40S TO MID 50S WITH HIGHS ON TUESDAY
IN THE UPPER 60S TO UPPER 70S. LOWS TUESDAY NIGHT ARE EXPECTED TO BE
IN THE MID 40S TO LOWER 50S WITH HIGHS ON WEDNESDAY IN THE MID 70S
TO LOWER 80S.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
A FRONTAL SYSTEM TO OUR SOUTH AND EAST WILL STALL TODAY...AS A
WAVE OF LOW PRESSURE MOVES ALONG IT THIS AFTERNOON AND TONIGHT.
THIS WILL BRING SHOWERS TO THE REGION...WITH A SOAKING RAINFALL
LIKELY FROM THE CAPITAL REGION AND POINTS SOUTH AND EAST THIS
AFTERNOON AND TONIGHT. THE GREATEST IMPACT ON THE TAF SITES WILL
BE AT KPOU WITH LESSER IMPACTS FARTHER NORTH. CONDITIONS WILL
GENERALLY BE VFR/MVFR THROUGH TONIGHT...ALTHOUGH CANNOT RULE OUT
SOME BRIEF PERIODS OF IFR PARTICULARLY AT KPOU AND KPSF.
LIGHT AND VARIABLE WINDS WILL BECOME NORTHERLY AT LESS THAN 10
KNOTS AND CONTINUE THROUGH TONIGHT.
OUTLOOK...
FRIDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
SATURDAY NIGHT: MODERATE OPERATIONAL IMPACT. LIKELY SHRA.
SUNDAY: MODERATE OPERATIONAL IMPACT. LIKELY SHRA.
SUNDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
&&
.FIRE WEATHER...
A DEVELOPING WAVE OF LOW PRESSURE TRACKING ALONG A FRONTAL
BOUNDARY TO OUR SOUTHEAST SHOULD BRING A SOAKING RAINFALL TO MOST
OF THE REGION THIS AFTERNOON AND TONIGHT. HOWEVER...ONLY SPOTTY
LIGHT RAIN OR SPRINKLES ARE EXPECTED ACROSS THE WESTERN
ADIRONDACKS IN EXTREME NORTHERN HERKIMER/HAMILTON COS...AND NW
WARREN CO.
THE RH SHOULD FALL INTO THE 50-70 PERCENT RANGE THIS
AFTERNOON...EXCEPT 40-50 PERCENT ACROSS NORTHERN HERKIMER AND
HAMILTON COS. THE RH SHOULD RECOVER TO 90-100 PERCENT
TONIGHT...THEN FALL TO 45-60 PERCENT FRI AFTERNOON.
WINDS WILL BECOME NORTH TO NORTHEAST AT 5-10 MPH TODAY AND
TONIGHT...ALTHOUGH SLIGHTLY HIGHER WINDS OF 10-20 MPH COULD OCCUR
TONIGHT ACROSS THE HIGHER PEAKS OF THE GREEN MTNS...BERKSHIRES AND
TACONICS. WINDS WILL BECOME MAINLY NORTH ON FRIDAY AT 5-15 MPH.
&&
.HYDROLOGY...
RAINFALL AMTS OF 1 TO 2 INCHES ARE EXPECTED FROM THE SOUTHEAST
CATSKILLS...MID HUDSON VALLEY REGION...NW CT...WESTERN MA AND
SOUTHERN VT THROUGH FRI MORNING. GENERALLY UNDER AN INCH IS
EXPECTED TO THE N AND W OF THESE AREAS...WITH LITTLE IF ANY RAIN
OCCURRING ACROSS THE WESTERN ADIRONDACKS.
ALTHOUGH MAIN STEM RIVERS WILL ONLY EXHIBIT MINOR RISES FROM THIS
RAINFALL DUE TO DRY ANTECEDENT CONDITIONS...LOCALLY HEAVY
DOWNPOURS AND RAINFALL RATES OF ONE HALF INCH PER HOUR OR SLIGHTLY
GREATER COULD LEAD TO PONDING OF WATER IN LOW LYING...URBAN AND
POOR DRAINAGE AREAS THIS AFTERNOON AND TONIGHT...ESP ACROSS THE
MID HUDSON VALLEY...NW CT...AND WESTERN MA.
THE NEXT THREAT OF RAIN WILL ARRIVE LATE SATURDAY INTO SUNDAY AS A
LOW PRESSURE SYSTEM APPROACHES FROM THE SOUTH AND WEST. MODERATE
RAINFALL AMTS...POSSIBLY IN THE ONE HALF INCH TO ONE AND ONE HALF
INCH RANGE COULD OCCUR...LEADING TO ADDITIONAL MINOR RISES ON AREA
RIVERS/STREAMS.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...KL/WASULA
NEAR TERM...KL/WASULA
SHORT TERM...KL
LONG TERM...11
AVIATION...11
FIRE WEATHER...HWJIV/KL
HYDROLOGY...HWJIV/KL
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
11 AM EDT THU SEP 10 2015
.DISCUSSION...
MORNING CAPE SOUNDING SHOWS DEEP LAYER W/SW FLOW THROUGH THE COLUMN
WITH PWAT AROUND 2 INCHES. TEMPS ALOFT REMAIN RATHER WARM...+9.5C AT
700 MB AND -6.5C AT 500 MB. UPSTREAM AT TBW...THEIR DATA SHOWS SOME
NOTICEABLY DRIER AIR (PWATS 1.79") WHICH SHOULD ADVECT INTO ECFL.
THE OFFSHORE FLOW WILL DELAY THE SEA BREEZE BUT AN ONSHORE FLOW WILL
DEVELOP SOUTH OF THE CAPE WHICH SHOULD SPARK SCT STORMS ALONG AND
JUST INLAND FROM THE COAST THIS AFTERNOON. THE PERSISTENT BAND OF
SHOWERS AND ISOLATED STORMS NW OF THE AREA EXTENDING INTO THE GULF
IS ASSOCD WITH CONVERGENCE TYPICALLY FOUND ON THE NORTH SIDE OF THE
RIDGE AXIS AND IS NOT SHOWING MUCH MOVEMENT. IT DOES NOT APPEAR TO BE
ASSOCD WITH A SFC BOUNDARY BUT OUTFLOW FROM THIS CONVECTION MAY
PROPAGATE INTO OUR NORTHERN SECTIONS THIS AFTN AND SPARK SOME ADDL
STORMS. SO THE POP DISTRIBUTION OF 30 PERCENT NORTH AND 40 PERCENT SOUTH
LOOKS GOOD AND DID NOT MAKE SIG CHANGES TO THE FCST.
TODAY-TONIGHT (PREVIOUS)...
ATLC RIDGE AXIS CENTERED OVER THE NRN BAHAMAS AND EXTENDING INTO THE
WRN GOMEX WILL INTERACT WITH A DEEP AND SLOW MOVING FRONTAL TROF
PRESSING INTO THE MID/DEEP SOUTH TO GENERATE A SWRLY BREEZE THRU THE
COLUMN ACRS CENTRAL FL. RAP ANALYSIS OF THE MOISTURE FIELDS SHOWS AN
AIRMASS SLIGHTLY ON THE DRY SIDE...MEAN RH GENERALLY AOB 70PCT THRU
THE H100-H70 LYR AND BLO 60PCT THRU THE H85-H50 LYR.
EVENING SOUNDINGS REFLECT THIS WITH PWAT VALUES BTWN 1.8"-2.0"...BUT
WITH A SUBSTANTIAL AMOUNT OF MID LVL DRY AIR: AVG DEWPOINT
DEPRESSIONS THRU THE H85-H50 LYR BTWN 7-10C DEG...WITH READINGS OVER
10C NOSING THEIR WAY UP THE I-4 CORRIDOR. MUCH OF THE MOISTURE IS
ASSOCIATED WITH A PLUME OF UPR LVL DEBRIS CLOUDS FROM CONVECTIVE
ACTIVITY OFF THE COAST OF GUATEMALA AND THE YUCATAN PENINSULA.
H85-H30 VORTICITY AND H30-H20 DIVERGENCE FIELDS REMAIN QUITE WEAK
WITH LITTLE CHANGE ANTICIPATED AS THE STRENGTH...DEPTH...AND
POSITION OF THE RIDGE WILL DEFLECT ANY ENERGY RIPPLES FROM ADVECTING
INTO THE CENTRAL PENINSULA. MID LVL TEMP PROFILE A BIT MORE UNSTABLE
THAN WED: A WEAK H70 THERMAL RIDGE REMAINS DRAPED OVER CENTRAL FL
WITH READINGS ARND 10C...H50 TEMPS ARND -6C BUT WITH POTENTIAL TO
DROP TO ARND -7C AS THE FRONTAL TROF PRESSES INTO THE THE NW FLANK
OF THE RIDGE AND SHUNTS COOLER AIR IN FROM THE NE GOMEX. INDEED...
GFS INDICATING LAPSE RATES IN THE H70-H50 LYR STEEPENING TO BTWN
6.5-7.0C/KM BY DAYBREAK.
UPR LVL DEBRIS CLOUDS WILL COMBINE WITH THE DRIER MID LVL AIR AND
WEAK DYNAMIC SUPPORT TO KEEP PRECIP CHANCES BLO 50PCT. BRISK SW FLOW
ACRS THE NRN CWA AS THE FRONTAL TROF BEGINS TO INTERACT WITH THE
ATLC RIDGE...SEA BREEZE FORMATION NOT EXPECTED FROM THE CAPE
NWD...WILL GO WITH LOWER POPS ALONG AND N OF THE I-4 CORRIDOR.
WEAKER FLOW S OF THE CAPE WILL ALLOW THE SEABREEZE TO FORM BUT WILL
KEEP IT SUPPRESSED ALONG THE I-95 CORRIDOR...WILL GO WITH HIGHER
POPS THERE...MARTIN/ST. LUCIE COUNTIES SLIGHTLY LOW TO ACCOUNT FOR
THE SHADOW EFFECT OF LAKE OKEECHOBEE. WITH LIMITED DYNAMIC
SUPPORT...PRECIP SHOULD BURN OUT SHORTLY AFT SUNSET...WILL KEEP 20
POPS ALONG THE COAST AND ARND LAKE OKEECHOBEE THRU 02Z TO ACCOUNT
FOR BLOW BACK PRECIP IN THE SW FLOW REGIME.
WARM S/SW BREEZE WILL PUSH MAX TEMPS INTO THE L/M90S...WHILE SFC
DEWPOINTS IN THE M70S SUGGEST OVERNIGHT MIN TEMPS ON THE SAME ORDER.
&&
.AVIATION...
A LIGHT W/SW FLOW WILL TURN ONSHORE (SE) AT COASTAL TERMINALS TIX SOUTH
THIS AFTERNOON. COVERAGE AGAIN LOOKS HIGHER ACROSS THE SOUTH WHERE
MOISTURE IS A BIT HIGHER SO TEMPO GROUPS LOOK OK THERE. BUT WILL REVISIT
THE NEED FOR TEMPO GROUPS ACROSS THE NORTH (MCO/SFB/DAB) WHERE LOWER
COVERAGE IS EXPECTED. WILL MAINTAIN AT LEAST VCTS.
&&
.MARINE...
NO SIGNIFICANT CHANGES TO CURRENT COASTAL WATERS FORECAST.
TODAY/TONIGHT...HI PRES RIDGE ANCHORED NE OF THE BAHAMA BANK
EXTENDING INTO THE WRN GOMEX WILL GENERATE A LIGHT TO GENTLE SWRLY
BREEZE OVER THE LCL ATLC...BCMG S/SE NEAR THE COAST S OF CAPE
CANAVERAL IN THE AFTN DUE TO THE FORMATION OF THE EAST COAST SEA
BREEZE. SEAS ARND 2-3FT. WINDS MAY FRESHEN TO A MODERATE SW BREEZE
OVER THE OFFSHORE LEG N OF SEBASTIAN INLET OVERNIGHT AS A FRONTAL
TROF PRESSES INTO THE DEEP SOUTH AND INTERACTS WITH THE RIDGE.
PRIMARY MARINE HAZARD WILL BE SCT AFTN TSTMS MOVING OFFSHORE DUE TO
THE PREVAILING S/SWRLY BREEZE...MAINLY FROM FT PIERCE INLET NWD.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 91 75 91 75 / 30 20 40 30
MCO 93 75 91 75 / 30 10 50 30
MLB 91 77 90 75 / 40 20 50 30
VRB 91 75 90 75 / 30 20 50 30
LEE 93 75 90 75 / 30 10 50 30
SFB 94 76 92 76 / 30 10 50 30
ORL 93 75 91 76 / 30 10 50 30
FPR 91 75 91 75 / 30 20 50 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
KELLY/PENDERGRAST
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1013 AM CDT THU SEP 10 2015
.UPDATE...
ISSUED AT 1004 AM CDT THU SEP 10 2015
Outflow boundary from convection in northern Illinois showing up
nicely on regional radar mosaics, located just north of I-80 at 10
am. This may slip into the far northern CWA over the next couple
hours, although latest HRRR does not show much further south
progress. However, the actual cold front will be advancing into
southeast Iowa through midday, and the combination of this and the
remnants of the outflow will start to trigger additional shower
and thunderstorm development. PoP`s have been adjusted a bit to
time the higher chances of rain, largely keeping the rest of the
morning dry.
Little change needed to overall high temperatures, but have made
some adjustments to the hourly trends. Arrival of convection will
likely result in some falling temperatures over the far northwest
later this afternoon.
&&
.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT THU SEP 10 2015
Narrow ridge over the area is keeping clear skies across the central
and southeast parts of the CWA early this morning. Where high clouds
were last to clear last night, dense fog has developed; which is
mainly in southeast IL. Considering a dense fog advisory for about 5-
6 hours this morning. Will make last minute decision on this.
Believe this fog will likely last for a couple of hours this
morning. As the ridge moves east a frontal system will move in from
the northwest and bring the chance of showers and isolated
thunderstorms to areas northwest of a Jacksonville to Pontiac line,
mainly during the afternoon.
Cooler temps are expected today as cooler air advects into the area,
so below normal temps will occur across the whole CWA. Light winds
will become more westerly this afternoon, with wind speeds less than
10kts.
.LONG TERM...(TONIGHT THROUGH Wednesday)
ISSUED AT 330 AM CDT THU SEP 10 2015
Cold front exits southeast IL tonight with much cooler air ushering
into the region on increasing NW breezes especially by Friday
morning. A strong upper level trof digs into the area by 12Z/Fri and
will spread a good chance of showers from NW to SE across area
tonight, with southeast IL likely staying dry through this evening.
Instability parameters look weak for thunder and only carried
isolated thunder to central IL this evening and into southeast IL
overnight. Lows overnight in the upper 50s/lower 60s except near 55F
by Galesburg. Cooler highs Friday range from upper 60s NW of IL
river to mid 70s southeast of I-70 as mostly cloudy skies prevail
Friday. Chances of rain showers Friday will be mainly east of the IL
river with highest pops of 40-50% in eastern/SE IL.
Forecast models have trended stronger with upper level trof and
embedded cutoff upper level low over eastern/SE IL by Saturday
afternoon and gives isolated light rain showers in eastern IL from I-
57 east where more clouds expected. Cool highs in the mid to upper
60s on Saturday. Lows Friday night in the upper 40s/lower 50s and
then mid to upper 40s for lows Sat night.
Stronger upper level trof begins to pull east of IL across the ohio
river valley on Sunday with more sunshine expected and temps
moderating a bit with highs around 70F. Lows Sunday night mostly in
the lower 50s with eastern IL around 50F.
00Z medium and extended forecast models continue to show upper level
trof pulling away from IL during Mon-Wed time frame as upper level
ridge builds into the area and provides a stretch of dry weather.
Below normal temperatures early next week with highs Monday 75-
80F will climb to a bit above normal by Wed with highs in the 80s.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z Friday MORNING)
ISSUED AT 637 AM CDT THU SEP 10 2015
Besides some light fog possible at all TAF sites this morning, VFR
conditions will prevail at all sites next 24hrs. Light pcpn seen
on radar trends continues to dissipate as it move into the area
early this morning, so just expecting some high clouds this
morning at all sites, with scattered mid clouds at PIA and BMI
later this morning. As a cold front approaches the area this
afternoon, scattered clouds at around 7kft will advect over the
sites along with broken mid clouds around 15kft. Models differ on
amount of pcpn to be expected with FROPA, but will have only VCTS
at all sites with PIA first during the late afternoon and then BMI
early evening, then SPI/DEC/CMI all at 00z. Based on model timing
differences, will have VCTS for 6hrs at all sites, which results
in a mid level cig during the night around 10kft. Due to timing
and coverage differences in the models, will not have any
predominate pcpn and let later shifts fine-tune the TAFs and
things become more certain. Winds will be light ahead of the
front, and then become westerly to northwesterly with FROPA, and
then north-northwest behind the front for the afternoon and night.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Auten
LONG TERM...07
AVIATION...Auten
AREA FORECAST DISCUSSION
National Weather Service Dodge City KS
606 AM CDT THU SEP 10 2015
...Updated aviation discussion...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 121 AM CDT THU SEP 10 2015
Short range models indicate an upper level shortwave digging
southeastward across the Northern Plains into the Upper Midwest late
today. Meanwhile, an attendant cold front is projected to push
slowly southward into northwest and north central Kansas late this
afternoon. Although the flow aloft is expected to be less than
robust across western Kansas, ample moisture pooling ahead of the
approaching frontal boundary will provide plenty of instability with
SBCAPE values rising in excess of 2000 J/KG by this afternoon. Along
with increasingly more favorable vertical shear profiles developing
through the afternoon period, thunderstorm development will be
possible in the vicinity of the frontal boundary through Thursday
night as it moves further south into Oklahoma. A few storms could
become severe.
Above normal temperatures are likely today as a prevailing southerly
flow draws warmer air northward into the area. Highs pushing into
the lower to mid 90s(F) can be expected late this afternoon in
locations ahead of the approaching frontal boundary. Lows are
expected to be down into the 50s(F) and 60s(F) tonight as cooler air
filters southward into western Kansas behind the frontal boundary.
.LONG TERM...(Friday THROUGH Wednesday)
ISSUED AT 224 AM CDT THU SEP 10 2015
Drier conditions are likely through the weekend as medium
range models indicate a weak flow aloft associated with a ridge
of high pressure moving eastward across the Intermountain West
into the Western High Plains during the period. Meanwhile, a
significant drop in temperatures is likely Friday as much cooler
air filters southward into western Kansas in wake of a cold
frontal passage late Thursday. The GFS and ECMWF show H85
temperatures falling well down into the Teens(C) by late Friday.
Look for highs only up into the 70s(F) for the most part Friday
afternoon. A gradual warming trend is then expected with highs
back up into the 90s(F) early next week as the aforementioned
upper level ridging moves out of the Central Rockies into the
high plains.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z Friday MORNING)
ISSUED AT 603 AM CDT THU SEP 10 2015
Early morning convection will taper off from north to south
through 15z as one upper level disturbance crosses western Kansas.
The chance for thunderstorms will then return after 18z as a cold
front moves south across western Kansas during the afternoon and
early evening. At this time it appears the better chances for
afternoon thunderstorms will be at Hays and Dodge City with these
storms shifting south and east of these airports by or shortly
after sunset. 06z BUFR soundings along with the latest RAP and
HRRR all indicating mainly low VFR ceilings with these storms
later this afternoon. Southerly winds ahead of the cold front will
shift to the northeast as the cold front passes late today and
early tonight. In addition to the wind shift the 06z NAM along
with the RAP indicated some low level moisture will begin to
return to western Kansas behind the cold front. At this time will
trend towards MVFR conditions behind the cold front after 03z
Friday.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 92 59 75 54 / 40 50 20 0
GCK 90 58 76 55 / 20 20 20 0
EHA 92 59 75 56 / 10 20 20 10
LBL 92 60 76 56 / 40 50 20 10
HYS 90 57 75 52 / 30 40 20 0
P28 92 63 78 55 / 60 60 20 0
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...JJohnson
LONG TERM...JJohnson
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1105 AM EDT THU SEP 10 2015
.UPDATE...
ISSUED AT 1105 AM EDT THU SEP 10 2015
UPSTREAM COLD FRONT CURRENTLY EXTENDS FROM CENTRAL UPPER MICHIGAN
THRU WISCONSIN INTO FAR ERN IOWA. THICK LINE OF SHOWERS CONTINUES
TO SLOWLY MOVE EASTWARD THRU OUR CWA LATE THIS MORNING. SOME
HIGHER REFLECTIVITIES...WHICH MAY HAVE RESULTED IN A FEW HITS OF
LIGHTNING...WERE NOTED AN HOUR OR SO AGO OVER LAKE MICHIGAN...BUT
HAVE SINCE DIMINISHED IN INTENSITY. NAM12...RAP13 AND HRRR ALL
SHOW VERY WEAK INSTABILITY DEVELOPING THIS AFTERNOON/EVENING
ACROSS OUR CWA...WITH CAPES ONLY INCREASING TO 500 JOULES OR LESS.
SOME WEAK COOLING ALOFT COMBINED WITH LIMITED LOW LEVEL DIURNAL
HEATING WILL LEND TO MINOR DESTABILIZATION THIS AFTERNOON...WHICH
MAY LEAD TO A FEW ADDITIONAL HITS OF LIGHTNING. HAVE ADDED A
SLIGHT CHANCE OF THUNDER TO ENTIRE CWA THIS MORNING...AND
CONTINUED THIS THRU THE AFTERNOON AS WELL. HAVE ALSO INCREASED
POPS IN MOST LOCATIONS...AND MAY NEED TO FURTHER INCREASE POPS IN
OUR ERN CWA IF THIS AREA OF SHOWERS CONTINUES TO HOLD TOGETHER.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 353 AM EDT THU SEP 10 2015
...A FEW SHOWERS AND POSSIBLY A THUNDERSTORM OR TWO TODAY...
SLOWLY FALLING HEIGHTS THROUGH THE PERIOD AS UPPER LEVEL TROUGHING
CENTERED ACROSS CENTRAL CANADA DIGS INTO THE GREAT LAKES. SHORT
WAVES MOVING THROUGH THE FLOW IN COMBINATION WITH CONVERGENCE ALONG
A SURFACE COLD FRONT WILL LEAD TO INCREASING SHOWER CHANCES TODAY
(FIRST ACROSS NORTHWEST ZONES THIS MORNING THEN FOR MUCH OF THE
REGION THIS AFTERNOON). IN ADDITION...A BIT OF INSTABILITY
(SEVERAL HUNDRED J/KG OF 0-1 KM MIXED LAYER CAPE) WILL LEAD TO
SLIGHT CHANCES FOR THUNDER THIS AFTERNOON. AS THE COOLER AIR
DEEPENS TONIGHT THE CHANCES FOR LAKE EFFECT RAIN SHOWERS INCREASE
AS 850 MB TEMPS DROP TO BETWEEN PLUS 3 AND PLUS 5 C. HIGHS TODAY
NEAR AVERAGE FOR THE DATE...UPPER 60S AND LOWER 70S. COOLER
TONIGHT THAN ANY TIME RECENTLY WITH LOWS IN THE MIDDLE 40S TO
MIDDLE 50S.
&&
.SHORT TERM...(FRIDAY THROUGH SATURDAY NIGHT)
ISSUED AT 353 AM EDT THU SEP 10 2015
HIGH IMPACT WEATHER: WATERSPOUT POTENTIAL ON FRIDAY NIGHT AND
SATURDAY.
FORECAST CHALLENGE: LAKE EFFECT RAIN POTENTIAL, AND WATERSPOUT
POTENTIAL FOR FRIDAY AND SATURDAY.
(9/11)FRIDAY...THE MAIN FRONT IS SOUTH OF THE FORECAST AREA, AND THE
COLD AIR ADVECTION IS REALLY PRESSING IN BY 12Z. IN FACT, THE GFS
HAS BECOME MUCH MORE AGGRESSIVE WITH THE COLD AIR AS IT HAS +2C IN N
LAKE MICHIGAN, WHILE THE ECMWF IS AROUND 4C. WINDS IN THE 1000-850
MB LAYER ARE OUT OF THE NNW MOST OF THE DAY, WITH THE MOISTURE IN
THE 850-700 MB LAYER AROUND 70% MOST OF THE DAY AS WELL. (REMEMBER
THE WATER TEMPERATURES ARE STILL AROUND 20C IN N LAKE MICHIGAN.
STILL A LITTLE CONCERNED IN E LAKE SUPERIOR WITH 15-20C WATER, BUT
IT LOOKS LIKE THE 850 MB TEMPERATURES ONLY FLIRT WITH 0C, WHICH
WOULD CAUSE MORE INSTABILITY AND RAIN SHOWERS FOR BETTER LAKE EFFECT
RAIN THERE, BUT AS IT STANDS, THERE WILL BE MARGINAL INSTABILITY IN
E UPPER AS THE WINDS CONTINUE TO VEER NORTH THROUGH THE NIGHT. SO
THIS LOOKS TO AFFECT THE REGION FROM AROUND TVC TO AND WEST ALONG
THE LAKE MICHIGAN SHORELINE TO MBL. SOUNDINGS DURING THE DAY AND
INTO THE NIGHT, DON`T LOOK THAT GREAT AS THE SOUNDINGS LOOK A LITTLE
DRY, TO ME. SO HAVE KEPT THE POPS TO HIGH CHANCE OVER N FLOW
REGIONS. OF COURSE WITH THE TALK OF LAKE EFFECT RAIN, THE CHANCE FOR
WATER SPOUTS IS HIGHER, WITH THE 500 MB CUT OFF LOW ROTATING OVER
THE REGION AND EQUILIBRIUM LEVELS OF AROUND 10K FEET IF MODIFYING TO
THE LOWER PART OF THE SOUNDINGS TO THE WATER TEMPERATURES.
(9/12)SATURDAY...IT LOOKS LIKE THAT THE BEGINNING OF THE DAY SHOULD
CONTINUE THE CHANCE FOR LE RAIN SHOWERS IN THE WEST, WITH THE CHANCE
FOR WATERSPOUTS AS WELL, BUT THE LATER WE GET INTO THE DAY, THE
SOUNDINGS BEGIN TO DRY OUT SO THAT BY 00Z, THE SKIES SHOULD BEGIN TO
CLEAR OUT ALONG THE LAKE MICHIGAN SHORELINE. ESPECIALLY AS THE 850
MB TEMPERATURES WARM WITH THE SFC HIGH BUILDING INTO THE REGION, AND
THE 500 MB LOW MOVING OFF TO THE EAST.
&&
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 353 AM EDT THU SEP 10 2015
WITH THE 500 MB LOW MOVING TO
THE EAST, THE PATTERN BECOMES QUITE AMPLIFIED AS 500 MB RIDGING
DOMINATES THE UPPER GREAT LAKES THROUGH TUESDAY NIGHT. THEN
WEDNESDAY, AND IT LOOKS LIKE LATE IN THE DAY, THE RIDGE BEGINS TO
BREAK DOWN WITH THE ANOTHER COLD FRONT WITH THE CHANCE FOR RAIN TO
MOVES INTO THE REGION OVERNIGHT WEDNESDAY AND INTO THURSDAY.
TEMPERATURES LOOK TO BE ABOVE NORMAL FOR A DAY OR TWO BEFORE COMING
BACK DOWN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 702 AM EDT THU SEP 10 2015
MID LEVEL CLOUD HAVE OVERSPREAD THE REGION AND WILL CONTINUE
ACROSS THE AREA TODAY. MEANWHILE...LIGHT RAIN SHOWERS WILL
OVERSPREAD THE TAF SITES THIS MORNING AND CONTINUE INTO THIS
AFTERNOON. A RUMBLE OF THUNDER CANNOT BE RULED OUT...BUT TOO
ISOLATED TO INCLUDE IN THE TAFS. A COLD FRONT MOVES THROUGH THIS
AFTERNOON...WITH WINDS SHIFTING INTO THE WEST NORTHWEST. SPEEDS
ALL UNDER 10 KTS. LAKE EFFECT RAIN SHOWERS WILL LIKELY DEVELOP
LATER TONIGHT. CIGS/VSBYS LIKELY VFR FOR MUCH OF TODAY...TRENDING
MVFR TONIGHT.
&&
.MARINE...
ISSUED AT 353 AM EDT THU SEP 10 2015
WINDS WILL BE SOUTHWEST TODAY THEN A COLD FRONT PASSES...SHIFTING
WINDS INTO THE NORTH TONIGHT. COLDER AIR AND AN UPPER LEVEL TROUGH
OVER THE GREAT LAKES REGION WILL RESULT IN WATERSPOUTS BECOMING A
GREATER THREAT...ESPECIALLY FRIDAY NIGHT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...MLR
NEAR TERM...SULLIVAN
SHORT TERM...JSL
LONG TERM...JSL
AVIATION...SULLIVAN
MARINE...SULLIVAN
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
935 AM EDT THU SEP 10 2015
LATEST UPDATE...
MARINE
.SYNOPSIS...
ISSUED AT 325 AM EDT THU SEP 10 2015
A TASTE OF EARLY FALL WILL COME SOUTHWEST MICHIGAN AS A POLAR COLD
FRONT MOVES ACROSS THE AREA LATER THIS AFTERNOON INTO EARLY
TONIGHT. THIS WILL BRING THE COOLEST AIR THIS AREA HAS SEEN SINCE
EARLY JUNE. SCATTERED SHOWERS WILL OVERSPEAD THE AREA FROM
NORTHWEST TO SOUTHEAST THIS AFTERNOON INTO THIS EVENING AS THE
COLD FRONT CROSSES THE AREA. FOR FRIDAY AND SATURDAY EXPECT
CONSIDERABLE CLOUD COVER...HIGHS ONLY FROM AROUND 60 TO THE MID
60S AND SCATTERED LAKE EFFECT SHOWERS. THE SHOWERS WILL BE
NUMEROUS NEAR THE LAKE MICHIGAN SHORE. SUNDAY INTO MONDAY THE COLD
AIR STARTS TO PULL AWAY FROM THE AREA SO SKIES WILL CLEAR AND
TEMPERATURES WILL SLOWLY WARM EACH DAY.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM EDT THU SEP 10 2015
OUR PRIMARY ISSUES ARE THE THREAT OF CONVECTION WITH THE COLD
FRONT THIS AFTERNOON INTO THIS EVENING...THEN WE WILL FOCUS ON THE
POTENTIAL FOR NORTH WIND LAKE EFFECT RAIN SHOWERS FOR THE FIRST
TIME THIS SEASON FOR FRIDAY INTO SATURDAY. BY SATURDAY MORNING THE
850 TEMPERATURE ANOMALIES AND THE 500 HEIGHTS WILL BE AROUND 4
STANDARD DEVIATIONS FROM NORMAL OVER THE LOWER GREAT LAKES INTO
THE OHIO VALLEY.
A 130 KNOT JET ROUNDING THE BASE OF THE TROUGH IN THE GULF OF
ALASKA EARLY THIS MORNING WILL INCREASE TO NEAR 145 KNOTS BY
TONIGHT AS IT HEADS TOWARD SOUTHERN ALASKA. THAT PUMPS UP THE
DOWNSTREAM RIDGE OVER WESTERN NORTH AMERICA...WHICH IN TURN DEEPS
THE DOWN STREAM TROUGH (OVER THE NORTHERN PLAINS). BY FRIDAY
AFTERNOON WE WILL HAVE A 110 KNOT JET CORE DIVING SOUTHWARD INTO
THE DEEPENING TROUGH OVER THE CENTRAL CANADA AND THE NORTHERN
PLAINS AND GREAT LAKES. THIS ACTION WILL LEAD TO A CLOSED UPPER
LOW BY SATURDAY MORNING OVER INDIANA AND WESTERN OHIO.
SO AS TYPICAL OF THIS SORT OF SET UP...THERE IS A BAND OF
CONVECTION HEAD OF THE COLD FRONT. MOISTURE TRANSPORT VECTORS IN
THE 1000/850 LAYER FOCUS THE BEST SHOWERS OVER NORTHERN LOWER
MICHIGAN THIS AFTERNOON AND EVENING. EVEN SO WITH PRECIPITABLE
WATER VALUES RISING TO AROUND 1.2 INCHES (ABOUT 150 PERCENT OF
NORMAL) THERE SHOULD BE ENOUGH MOISTURE FOR SOME SHOWERS THIS
AFTERNOON INTO THIS EVENING. THERE IS SOME MARINGAL INSTABILITY BUT
THE THE BEST CHANCE FOR THUNDERSTORMS WILL BE OVER NORTHWEST
SECTIONS LATE THIS AFTERNOON. AFTER THAT INSTABILITY IS TO FEEBLE
FOR THUNDERSTORMS.
ONCE IN THE COLD AIR WE SET UP FOR A NORTH WIND LAKE EFFECT EVENT
THAT COMMENCES ON FRIDAY AND LASTS INTO SATURDAY. ON FRIDAY
SOUNDING SUGGEST THERE IS ENOUGH INSTABLITLY FOR EQUILIBRIUM
LEVELS TO BE NEAR 20000 FT... MORE THAN ENOUGH FOR SHOWERS. ON
SATURDAY THE MOISTURE DEPTH IS LESS SO THE SHOWERS WILL MOSTLY BE
NEAR THE LAKE SHORE. ANOTHER ASPECT TO THIS THAT FAVORS SHOWERS IS
THAT LOWER MICHIGAN IS IN THE DEEP COLD AIR...INSIDE THE
CYCLONICLY CURVED JET AROUND THE OUTSIDE OF THE UPPER LOW. THE
BACK SIDE OF THAT JET DOES NOT CROSS SOUTHWEST MICHIGAN UNTIL
SUNDAY AFTERNOON. HAVING 850 MB TEMPERATURES FALL TO BETWEEN 2C
AND 4C..GIVEN THE 20C LAKE TEMPERATURES WILL BE MORE THAN COLD
ENOUGH FOR LAKE EFFECT SHOWERS TOO. ONCE AGAIN...WITH NORTH WINDS
THE SHOWERS WILL BE MOSTLY NEAR AND WEST OF US-31 FRIDAY AFTERNOON
INTO SATURDAY AFTERNOON.
INLAND SATURDAY MORNING SKIES MAY CLEAR SOMEWHAT SO WE COULD SEE
LOWS IN THE UPPER 30S IN THE NORMAL COOLER AREAS. I DO NOT THINK
FROST IS AN ISSUE YET. THAT WILL NOT BE TO FAR DOWN THE ROAD
THROUGH.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 325 AM EDT THU SEP 10 2015
A DRY PATTERN IS SETTING UP FOR MUCH OF THE LONG TERM. THE UPPER
TROUGH WILL BE MOVE EAST OUT OF THE CWA SATURDAY NIGHT AND AS SKIES
CLEAR TEMPS SHOULD FALL INTO THE LOWER TO MID 40S WITH SOME OF THE
COLDER SPOTS IN THE NORTHERN CWA REACHING THE UPPER 30S. AS THE SFC
RIDGE AXIS MOVES EAST BEGINNING SUNDAY WE/LL SEE TEMPS BEGIN TO
RISE. SUNDAY WILL STILL BE COOL WITH HIGHS IN THE MID 60S BUT HIGHS
WILL CLIMB INTO THE 70S BY MONDAY AND MAY APPROACH 80 BY MID WEEK.
RIDGING AT THE SFC AND ALOFT WILL MEAN DRY WX THROUGH TUESDAY NIGHT
AND MUCH OF WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 719 AM EDT THU SEP 10 2015
VFR CONDITIONS WILL PREVAIL INTO TONIGHT. OVERNIGHT AS THE COLDER
AIR STARTS COMING IN CELLING WILL LOWER TO MVFR. SHOWERS SHOULD
BECOME MORE WIDESPREAD AT THAT POINT TOO.
THERE IS AN AREA OF SHOWERS AND A FEW THUNDERSTORMS JUST AHEAD OF
THE COLD FRONT OVER LAKE MICHIGAN AND BACK INTO SOUTHERN
WISCONSIN. THE SHOWERS OVER LAKE MICHIGAN ARE DISSIPATING DUE TO
THE LACK OF MID AND LOW LEVEL MOISTURE. HOWEVER... THE SHOWERS
CURRENTLY OVER SOUTHERN WISCONSIN ARE BETTER SUPPORTED AND THEY
MAY BRING SOME LIGHT RAIN SHOWERS TO AT LEAST THE WESTERN TAF
SITES THIS AFTERNOON. CEILING WILL REMAIN VFR AS WELL AS THE
VISIBILITY.
&&
.MARINE...
ISSUED AT 929 AM EDT THU SEP 10 2015
WINDS AND WAVES HAVE INCREASED IN THE NEARSHORE ZONES FROM
PENTWATER TO MUSKEGON AS THE BAND OF SHOWERS AND ISOLATED
THUNDERSTORMS COMES ONSHORE. RAP AND WAVE MODELS SHOW THIS
INCREASE IN THE NEAR TERM...WITH CONDITIONS DIMINISHING THIS
AFTERNOON. WILL KEEP THE MARINE PRODUCTS HEADLINE FREE FOR
NOW...AND INSTEAD INCREASE THE WAVE HEIGHTS AND WINDS SLIGHTLY.
&&
.HYDROLOGY...
ISSUED AT 1116 AM EDT WED SEP 9 2015
CONCERNS FOR FLOODING IN THE FORECAST AREA HAVE DRASTICALLY
DECREASED SINCE YESTERDAY AND REMAIN FAIRLY LOW THROUGH THE NEXT
SEVERAL DAYS.
24 TO 48 HOUR RAINFALL TOTALS THIS MORNING REFLECT THAT 2.00+ INCH
AMOUNTS WERE RELATIVELY HARD TO COME BY. AMOUNTS OF 1-2 INCHES
FELL IN A SWATH FROM MUSKEGON TO LUDINGTON AND EASTWARD TO MOUNT
PLEASANT AND HARRISON. A MAJORITY OF LOCATIONS TO THE SOUTH LANDED
IN THE TERRITORY OF ONE-QUARTER TO THREE-QUARTERS OF AN INCH WITH
EXCEPTION TO THOSE AFFECTED BY LOCALIZED HEAVY RAINFALL.
AREA RIVERS HAVE SHOWN UPWARD MOVEMENT...ESPECIALLY IN PLACES THAT
EXCEEDED 1.50 INCHES OF RAINFALL. FORTUNATELY...WE DODGED A
BULLET IN THE SENSE THAT NO REPORTS OF 3.00+ INCHES WERE RECEIVED IN
THE LAST 24 HOURS. THOSE WHO RECEIVED HEAVIER RAINFALL TWO DAYS
AGO...PARTICULARLY INGHAM COUNTY...WERE SPARED OF HEAVIER RAINFALL
YESTERDAY. OVERALL...THE NEXT 36 HOURS OF DRY WEATHER WILL BODE
WELL FOR STREAMS AND RIVERS TO STABILIZE AND BEGIN TRENDING
DOWNWARD. RAINFALL IS EXPECTED LATE THURSDAY INTO FRIDAY WITH
OVERALL AMOUNTS REMAINING AROUND OR LESS THAN ONE-HALF AN INCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...WDM
HYDROLOGY...JAM
MARINE...MWS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
747 AM EDT THU SEP 10 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT THU SEP 10 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A TROF EXTENDING S INTO
THE NCNTRL STATES AND UPPER GREAT LAKES...ANCHORED BY A MID LEVEL
LOW OVER NRN ONTARIO. SHORTWAVE MOVING ACROSS NRN ONTARIO IS HELPING
TO DRIVE A COLD FRONT SE...CURRENTLY ACROSS WRN LAKE SUPERIOR. DEEP
LAYER FORCING PER QVECTORS IS SUPPORTING AN AREA OF SHRA MOVING
ACROSS NE WI INTO SCNTRL UPPER MI EARLY THIS MORNING. ISOLD SHRA
HAVE BEEN OCCURRING FARTHER N TO LAKE SUPERIOR. EVEN A TSTM WAS
NOTED OVER ERN LAKE SUPERIOR A FEW HRS AGO.
AS FORCING SUPPORTING THE NE WI PCPN SHIFTS E...THIS MORE ORGANIZED
SHRA AREA WILL MOVE ACROSS THE SCNTRL AND PORTIONS OF THE ERN FCST
AREA OVER THE NEXT FEW HRS. THIS MAIN AREA OF PCPN SHOULD BE E OF
THE AREA NO LATER THAN MID MORNING. WITH COLD FRONT STILL PUSHING
SE...POTENTIAL IS THERE FOR ADDITIONAL ISOLD TO SCT SHRA DEVELOPMENT
UNTIL FROPA. THIS POTENTIAL SHOULD INCREASE DURING THE AFTN AS SOME
INSTABILITY BUILDS UP AHEAD OF COLD FRONT. DEVELOPING LAKE BREEZE
OFF LAKE MICHIGAN WILL ALSO STRENGTHEN THE LOW-LEVEL CONVERGENCE
ALONG THE SE MOVING COLD FRONT. RAP AND GFS SHOW MLCAPES UPWARDS OF
200-300J/KG OVER THE SCNTRL/SE FCST AREA. 00Z NAM SHOWED MLCAPE OVER
1000J/KG. WHILE THE 06Z NAM HAS PULLED BACK TO 600-800J/KG...IT
STILL LOOKS OVERDONE. IN ANY EVENT...THE AVBL INSTABILITY SUGGESTS
THE POTENTIAL FOR ISOLD TSTMS OVER THE SCNTRL/SE FCST AREA THIS AFTN
ALONG/AHEAD OF COLD FRONT.
CAA TODAY/TONIGHT WILL DROP 850MB TEMPS DOWN TO 0 TO 2C OVER LAKE
SUPERIOR BY 12Z FRI...SUFFICIENT FOR LAKE EFFECT PROCESSES WITH
WATER TEMPS ROUGHLY 15-18C. WITH NAM/GFS FCST SOUNDINGS SHOWING A
WELL MIXED LAYER IN LOWER 2KFT OF THE AIR MASS...BELIEVE IT WILL
TAKE SOME TIME TO GET LAKE EFFECT GOING TONIGHT...ESPECIALLY IN
LIGHT OF THE LACK OF SYNOPTIC SUPPORT WITH DEEP LAYER QVECTOR
DIVERGENCE DOMINATING. NOT EXPECTING ANYTHING MORE THAN ISOLD TO
PERHAPS SCT -SHRA COVERAGE. WITH WATER TEMPS MORE IN THE 12-15C
RANGE OVER THE ERN LAKE...-SHRA COVERAGE WILL BE LEAST OVER THE ERN
FCST AREA. IN FACT...THERE MAY NOT BE ANY LAKE EFFECT -SHRA OVER THE
FAR E TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 316 AM EDT THU SEP 10 2015
UPPER PATTERN CONSISTS OF A 500 MB RIDGE OVER THE WESTERN U.S. WITH
A TROUGH OVER THE UPPER GREAT LAKES 12Z FRI WITH A DEEP TROUGH OVER
THE EAST HALF OF THE U.S. THE TROUGH AXIS IS OVER THE CWA 12Z FRI
AND SLOWLY MOVES TO THE EAST BY 00Z SAT. THE TROUGH CONTINUES TO DIG
SOUTHEAST WITH A DEEP TROUGH OVER THE ERN U.S. ON SAT.
WITH THE TROUGH AXIS MOVING ACROSS THE AREA ON FRI...STILL NEED TO
KEEP SOME POPS IN THE FORECAST ESPECIALLY FOR DIURNALLY DRIVEN
SHOWERS. ALSO IS COLD ENOUGH FOR LAKE EFFECT CONTRIBUTION AS WELL AS
LAKE SUPERIOR TEMPERATURES RANGE FROM 10C TO 15C AND 850 MB RANGE
FROM 0C TO 2C ON FRIDAY AND THAT IS ENOUGH LAKE-850 MB DELTA-T TO
DEFINITELY HAVE SOME LAKE CONTRIBUTION TO THE PCPN AS WELL. WITH
LOSS OF DIURNAL HEATING FRI NIGHT...DRY THINGS OUT AND KEEP THAT WAY
THROUGH SAT NIGHT. DID NOT MAKE TOO MANY CHANGES TO THE GOING
TEMPERATURES AS THEY LOOKED FINE. KEPT IN SOME PATCHY FROST FOR FRI
NIGHT AND SAT NIGHT IN THE INTERIOR WEST AS LOWS FALL TO THE MID 30S.
IN THE EXTENDED...GFS AND ECMWF SHOW A CLOSED 500 MB LOW OVER THE
LOWER GREAT LAKES 12Z SUN WITH A RIDGE OVER THE DESERT SW. SFC FRONT
ON IS PARALLEL WITH UPPER FLOW ON SUNDAY ACROSS SOUTH CENTRAL
CANADA. A BROAD 500 MB TROUGH OVER THE NORTHERN ROCKIES 12Z MON WILL
DIGS SOUTHEAST 12Z TUE WITH A SFC FRONT BECOMING STATIONARY OVER THE
AREA ON TUE. AS A RIDGE BUILDS INTO THE EASTERN U.S. ON WED...THIS
FRONT WILL HEAD BACK NORTH AS A WARM FRONT ON WED. WILL BE A WARMING
TREND STARTING ON MON WITH TEMPERATURES GOING ABOVE NORMAL. HAVE
SOME SLIGHT CHANCE POPS IN FOR TUE AND TUE NIGHT WITH THE FRONT NEAR
THE AREA AND CHANCE POPS ON WED AS THE FRONT MOVES NORTH AS A WARM
FRONT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 746 AM EDT THU SEP 10 2015
VFR CONDITIONS WILL PREVAIL THRU AT LEAST THE EARLY EVENING HRS AT
KIWD/KCMX/KSAW. THERE MAY BE -SHRA THIS AFTN AT KSAW...BUT POTENTIAL
IS TOO LOW AT THIS POINT TO INCLUDE A MENTION IN FCST. INCREASINGLY
COLDER AIR...AN INCREASE IN LOW-LOW LEVEL MOISTURE AND UPSLOPE FLOW
SHOULD RESULT IN MVFR CIGS DEVELOPING AT ALL TERMINALS OVERNIGHT.
LIGHT LAKE EFFECT SHRA ARE ALSO POSSIBLE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT THU SEP 10 2015
PASSING COLD FRONT THIS MORNING FOLLOWED BY INCREASINGLY COLDER AIR
FLOWING INTO THE UPPER GREAT LAKES WILL RESULT IN INCREASING WINDS
ON LAKE SUPERIOR TODAY AND TONIGHT. WINDS SHOULD BE MOSTLY UNDER
20KT THRU THE MORNING BEFORE GUSTS RAMP UP AND REACH 20-30KT
TONIGHT. STRONGEST WINDS SHOULD BE ACROSS CNTRL LAKE SUPERIOR. WHILE
WINDS WILL SLOWLY DIMINISH OVER THE WRN LAKE ON FRI...20-30KT WINDS
WILL CONTINUE OVER THE E. HIGH PRES RIDGE ARRIVES SAT...RESULTING IN
WINDS FALLING OFF TO UNDER 15KT. INCREASING S TO SW WINDS ARE
EXPECTED SUN INTO MON AS HIGH PRES RIDGE DEPARTS AND A LOW PRES TROF
APPROACHES FROM THE NW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...07
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
633 AM CDT THU SEP 10 2015
.UPDATE...
Issued at 0540 AM CDT THU SEP 10 2015
A small convective complex near Kansas City has thus far refused
to die this morning, despite the loss of nearly all of its low
level jet support. With the HRRR now suggesting that this complex
may well hold together into southern Missouri, have gone ahead and
added PoPs along it`s expected path, which for now is from roughly
Clinton to Springfield. Trends will be monitored with additional
adjustments to PoPs likely over the next few hours.
&&
.SHORT TERM...(Today and Tonight)
Issued at 0240 AM CDT THU SEP 10 2015
This morning is starting out rather mild across the region, with
temperatures at 2 AM generally in the mid to upper 60s. Despite
ample low level moisture and T/Td spreads of only a degree or two,
fog has been slow to form so far, likely due to the presence of
very light southerly winds, and the approach of scattered cirrus
from the northwest. That said, I do think there is still the
potential for fog to form through sunrise, though it may not end
up being quite as widespread as initially thought.
Light south to southwest winds and high cloud cover can be
expected today, with temperatures warming into the low to mid 80s
by this afternoon.
A cold front currently located across the Great Lakes and northern
Plains will sharpen and accelerate south this evening into
tonight, and pass through the forecast area from north to south
during the overnight hours into Friday morning. Initial convection
near the KC area late this afternoon may be strong to severe, and
we will need to watch for the potential for a few of the stronger
storms to move into the northwestern corner of the CWA tonight.
For most of the forecast area, however, it appears that
instability will be low enough to preclude widespread severe
weather with this system. Gusty 40-50 MPH winds will still be
possible late tonight as convection moves through the area,
however.
.LONG TERM...(Friday through Wednesday)
Issued at 0240 AM CDT THU SEP 10 2015
The front should clear the area by mid day Friday, with a much
cooler and drier airmass quickly building into the area. A few
lingering showers/storms will be possible over far southern/south
central Missouri early Friday, but dry weather is expected for
most. Right now, it appears that highs on Friday may only reach
the low to perhaps mid 70s, with dewpoints quickly falling into
the low 50s by afternoon.
Even cooler conditions are then expected Friday night through
Sunday, with low temperatures around 50 Saturday morning, and
Sunday morning lows dropping into the 40s for most! Highs on
Saturday and Sunday will be in the upper 60s to around 70
degrees, some 10-15 degrees below average.
Expansive high pressure will continue to build across the
Southeastern U.S. through the early part of next workweek. This
will eventually result in southerly return flow across the Ozarks
by Tuesday and Wednesday, with temperatures (and dewpoints)
increasing back to or above normal values. The increase in
temperatures and humidity should result in a corresponding
increase in thunderstorm potential by the middle of next week.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 0623 AM CDT THU SEP 10 2015
With a weakening cluster of storms dropping southeast from Kansas
City this morning, went ahead and included tempo group for storms
around mid morning at Springfield and Joplin. Otherwise, will
bring in another vicinity/tempo group for afternoon convective
potential with approaching front/shortwave trough. Expect a wind
shift from south to northwest should occur between 04z and 08z
as the front drops quickly south of the MO border.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
UPDATE...Boxell
SHORT TERM...Boxell
LONG TERM...Boxell
AVIATION...Terry
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
540 AM CDT THU SEP 10 2015
.UPDATE...
Issued at 0540 AM CDT THU SEP 10 2015
A small convective complex near Kansas City has thus far refused
to die this morning, despite the loss of nearly all of its low
level jet support. With the HRRR now suggesting that this complex
may well hold together into southern Missouri, have gone ahead and
added PoPs along it`s expected path, which for now is from roughly
Clinton to Springfield. Trends will be monitored with additional
adjustments to PoPs likely over the next few hours.
&&
.SHORT TERM...(Today and Tonight)
Issued at 0240 AM CDT THU SEP 10 2015
This morning is starting out rather mild across the region, with
temperatures at 2 AM generally in the mid to upper 60s. Despite
ample low level moisture and T/Td spreads of only a degree or two,
fog has been slow to form so far, likely due to the presence of
very light southerly winds, and the approach of scattered cirrus
from the northwest. That said, I do think there is still the
potential for fog to form through sunrise, though it may not end
up being quite as widespread as initially thought.
Light south to southwest winds and high cloud cover can be
expected today, with temperatures warming into the low to mid 80s
by this afternoon.
A cold front currently located across the Great Lakes and northern
Plains will sharpen and accelerate south this evening into
tonight, and pass through the forecast area from north to south
during the overnight hours into Friday morning. Initial convection
near the KC area late this afternoon may be strong to severe, and
we will need to watch for the potential for a few of the stronger
storms to move into the northwestern corner of the CWA tonight.
For most of the forecast area, however, it appears that
instability will be low enough to preclude widespread severe
weather with this system. Gusty 40-50 MPH winds will still be
possible late tonight as convection moves through the area,
however.
.LONG TERM...(Friday through Wednesday)
Issued at 0240 AM CDT THU SEP 10 2015
The front should clear the area by mid day Friday, with a much
cooler and drier airmass quickly building into the area. A few
lingering showers/storms will be possible over far southern/south
central Missouri early Friday, but dry weather is expected for
most. Right now, it appears that highs on Friday may only reach
the low to perhaps mid 70s, with dewpoints quickly falling into
the low 50s by afternoon.
Even cooler conditions are then expected Friday night through
Sunday, with low temperatures around 50 Saturday morning, and
Sunday morning lows dropping into the 40s for most! Highs on
Saturday and Sunday will be in the upper 60s to around 70
degrees, some 10-15 degrees below average.
Expansive high pressure will continue to build across the
Southeastern U.S. through the early part of next workweek. This
will eventually result in southerly return flow across the Ozarks
by Tuesday and Wednesday, with temperatures (and dewpoints)
increasing back to or above normal values. The increase in
temperatures and humidity should result in a corresponding
increase in thunderstorm potential by the middle of next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1142 PM CDT WED SEP 09 2015
The combination of surface high pressure...light winds...and
residual low level moisture from the rainfall over the last
couple of days should be enough to bring on some fog overnight.
Several locations across the region are already in the 5-7SM
range at this hour. Expect visibilities to continue to fall
overnight. Will drop KSGF/KJLN down to 2SM with TEMPO to 1/2SM FG
while dropping KBBG to 1/4SM FG in roughly the 09-12z time frame.
Fog should begin to dissipate after sunrise with conditions
returning to VFR by around 15z. Next challenge then becomes
convection towards the end of the forecast period. Expect TSRA to
begin developing/moving in after 03z...so will add VCTS for
KSGF/KJLN after that time. For now...will leave out of KBBG as
believe convection will not affect that terminal until after the
end of the forecast period.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
UPDATE...Boxell
SHORT TERM...Boxell
LONG TERM...Boxell
AVIATION...Gaede
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
926 AM MDT THU SEP 10 2015
.UPDATE...
CURRENT FORECAST IS IN GOOD SHAPE WITH JUST A MINOR ADJUSTMENT MADE
WITH THIS UPDATE. SATELLITE IS SHOWING A WEAK DISTURBANCE MOVING
ACROSS SOUTHEAST MONTANA THIS MORNING. OBSERVATIONS SHOW MAINLY
HIGH CLOUD DECKS SO I REPLACED THE SHOWER WORDING WITH A CHANCE
FOR SPRINKLES. CLOUDS ARE BREAKING UP ACROSS THE NORTH SO POPS
HAVE BEEN SCALED BACK TO JUST OUR FAR SOUTHEAST COUNTIES AND
SHERIDAN COUNTY. SKIES HAVE BECOME MOSTLY SUNNY ACROSS OUR WEST.
EXPECT A PARTLY TO MOSTLY SUNNY DAY ACROSS THE WESTERN THIRD OF
OUR AREA WITH DECREASING CLOUDS AND PARTLY SUNNY SKIES THIS
AFTERNOON ACROSS OUR SOUTHEAST. TEMPERATURES WILL BE JUST A FEW
DEGREES COOLER THAN YESTERDAY WITH READINGS ABOUT NORMAL FOR THIS
TIME OF YEAR. HOOLEY
&&
.SHORT TERM...VALID FOR TDY AND FRI...
SEASONABLY WARM TEMPERATURES...LIGHT WINDS AND MAINLY DRY WEATHER
WILL CONTINUE TODAY AND FRIDAY.
TODAY...WE HAVE LINGERED A LOW-END SHOWER CHANCE OVER SOUTHEASTERN
MT THROUGH NOON MDT...AND WE DID DECIDE TO PULL THAT SLIGHT CHANCE
OF SHOWERS BACK SOUTHWEST INTO THE SHERIDAN AREA TOO. THAT WAS ALL
BASED ON OVERNIGHT RADAR TRENDS AS OF 0830 UTC AND RECENT RUNS OF
THE EXPERIMENTAL AND OPERATIONAL HRRR MODEL. THE SHORTWAVE TROUGH
RESPONSIBLE FOR THE EARLY-DAY SHOWER CHANCE WILL MOVE SOUTHEAST OF
THE AREA BY AFTERNOON AND SO WE DECIDED TO GO WITH A DRY FORECAST
EVERYWHERE AFTER 18 UTC EVEN THOUGH WE CANNOT ENTIRELY RULE OUT A
SPRINKLE IN SOUTHEASTERN MT THIS AFTERNOON. FORECAST HIGHS TODAY
WERE DRIVEN BY THE 00 UTC MULTI-MODEL CONSENSUS...AND ARE MAINLY
IN THE 70S F ON RELATIVELY LIGHT NORTH-NORTHEAST WINDS.
TONIGHT...THE 00 UTC GUIDANCE SHOWED ANOTHER AND WEAKER SHORTWAVE
TROUGH CROSSING SOUTHEASTERN MT IN NORTHWEST FLOW ALOFT DURING THE
EVENING. HOWEVER...WE CHOSE TO STAY WITH A DRY FORECAST FOR NOW AS
THE QG-FORCING WITH THE WAVE IS WEAK...THERE/S VERY LITTLE QPF IN
MODEL SIMULATIONS...AND MOS-BASED POPS ARE ALL BELOW 15 PERCENT.
WE THUS EXPECT A QUIET NIGHT WITH LOWS MAINLY IN THE 40S F ACROSS
THE AREA AS SURFACE HIGH PRESSURE SLIDES SOUTH ACROSS THE DAKOTAS.
FRIDAY...FLOW ALOFT WILL TURN DECIDEDLY ANTI-CYCLONIC AS A 500-MB
RIDGE OVER THE WESTERN UNITED STATES BUILDS EASTWARD. THE AIR MASS
WILL WARM AS A RESULT AND THUS TEMPERATURES WILL BE A BIT WARMER
THAN TODAY. SOME AREAS WILL LIKELY BE NEAR 80 F IN SOUTH CENTRAL
MT AND NORTH CENTRAL WY...BUT FORECAST SOUNDINGS SUGGEST MIXING
MAY BE SOMEWHAT LIMITED BY A SUBSIDENCE INVERSION JUST ABOVE 700
MB. WE RELIED ON THE 00 UTC MULTI-MODEL CONSENSUS FOR HIGHS GIVEN
THIS SCENARIO AND LITTLE SPREAD IN GUIDANCE OUTPUT. SCHULTZ
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
PATTERN CONTINUES TO LOOK WARM TO START...COOLER TO FINISH. AN
UPPER RIDGE WILL BUILD SATURDAY AND GET FLATTENED OUT BY ENERGY
RIDING ACROSS SOUTHERN CANADA ON SUNDAY. BACKING FLOW WITH
LOWERING HEIGHTS ON TAP FOR SUNDAY...BUT DESPITE THIS...BUMPED UP
FORECAST HIGHS. DOWNSLOPE FLOW WILL BE INCREASING WITH STRONGER
700MB WINDS IN A PRE FRONTAL ENVIRONMENT. RAISED HIGHS ON SUNDAY
TO MATCH THOSE OF SATURDAY. A COLD FRONT WILL PUSH THROUGH THE
AREA SUNDAY EVENING AND PROVIDE A COOLER DAY MONDAY.
MODELS THEN DIVERGE FROM TUESDAY ONWARD AND THE DIFFERENCES STEM
FROM THE DEVELOPING WESTERN TROUGH. THE GFS WAS STRONGER WITH THE
SOUTHERN STREAM ENERGY OF THE TROUGH AND THEREFORE DEEPER WITH IT
IN THE GREAT BASIN. THE ECMWF SWEEPS THE STRONGER ENERGY NORTH AND
WAS FLATTER WITH THE SOUTHERN EXTENT OF THE TROUGH FOR WARMER AND
DRIER WEATHER FOR TUESDAY. SINCE BOTH MODELS HIT THE AREA...IN
PARTICULAR THE WEST...WITH QPF...RAISED POPS FOR TUESDAY AND
TUESDAY NIGHT. DIFFERENCES EXIST FOR WEDNESDAY AS THE GFS WAS
WARMER AND DRIER WITH ZONAL FLOW...WHILE THE ECMWF MAINTAINS A
SOUTHWEST FLOW AND SENDS ENERGY UP FOR CHANCE POPS. TWH
&&
.AVIATION...
A FAIRLY QUIET WEATHER PATTERN WILL REMAIN IN PLACE WITH VFR
FLYING CONDITIONS EXPECTED. A WEAK DISTURBANCE WILL CREATE A FEW
SPRINKLES OR SOME VIRGA OVER SOUTHEAST MONTANA AND NORTHEAST
WYOMING THIS MORNING. OTHERWISE...NO PRECIPITATION EXPECTED WITH
CLOUDS BASES ABOVE 10 THOUSAND FEET. WINDS WILL BE LIGHT. TWH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 075 049/079 051/090 057/090 055/076 052/069 042/066
1/B 00/U 00/U 00/U 12/T 33/T 32/W
LVM 077 043/081 045/088 051/088 050/076 045/063 042/063
0/B 00/U 00/U 11/U 12/T 33/T 32/W
HDN 077 047/080 049/090 055/090 054/079 051/073 042/068
1/B 00/U 00/U 00/U 12/T 23/T 32/W
MLS 074 047/076 049/088 057/088 055/078 050/072 046/067
1/B 10/U 00/U 00/U 12/T 22/T 32/W
4BQ 073 047/075 049/086 056/089 056/080 051/073 049/070
2/W 10/U 00/U 00/U 11/B 22/T 42/W
BHK 070 045/072 046/083 053/086 053/078 049/073 048/067
1/B 10/U 00/U 00/U 12/T 22/T 32/W
SHR 076 044/078 045/087 050/088 051/080 048/073 044/069
2/W 10/U 00/U 00/U 12/T 23/T 41/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
346 AM PDT THU SEP 10 2015
.SYNOPSIS...MONSOON MOISTURE WILL KEEP THUNDERSTORMS IN THE FORECAST
ACROSS THE MOJAVE DESERT SOUTH OF LAS VEGAS AGAIN TODAY. MAINLY
DRY AND HOT CONDITIONS ARE EXPECTED FRIDAY AS HIGH PRESSURE
STRENGTHENS OVERHEAD. CONFIDENCE CONTINUES TO INCREASE IN MOISTURE
ASSOCIATED WITH TROPICAL STORM LINDA TO PUSH NORTH ACROSS THE
REGION THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.SHORT TERM...TODAY THROUGH SATURDAY MORNING.
CONVECTION FROM YESTERDAY AFTERNOON AND EVENING HAS DIMINISHED
ACROSS THE ENTIRE REGION. THE LATEST SATELLITE IMAGERY SHOWS MID-
LEVEL MOISTURE COURTESY OF TROPICAL STORM LINDA CONTINUING TO STREAM
FROM SOUTHWEST TO NORTHEAST ACROSS FAR SOUTHERN PORTIONS OF THE
FORECAST AREA. THIS WILL SET THE STAGE FOR ANOTHER DAY OF ISOLATED
TO SCATTERED THUNDERSTORMS ACROSS MAINLY MOHAVE AND SAN BERNARDINO
COUNTIES.
THE CLOUD SHIELD FROM LINDA WILL CONTINUE TO EASE NORTHWARD OVER THE
COURSE OF TODAY...WITH THE NORTHERN PERIPHERY OF THE CLOUD SHIELD
BEING A FAVORED REGION ALONG WITH TERRAIN FOR CONVECTIVE DEVELOPMENT
LATER THIS MORNING. THIS COINCIDES WITH THE FORECAST REGION OF BEST
INSTABILITY INDICATED ON THE LATEST RUNS OF THE NAM 12...WHICH WAS
THE BEST PERFORMING MODEL WITH INSTABILITY PARAMETERS YESTERDAY. THE
LATEST LOCAL HI-RES MODELS AND RUNS OF THE HRRR POINT TOWARD
CONVECTIVE INITIATION OCCURRING BETWEEN 18-19Z LATER TODAY ACROSS
CENTRAL AND SOUTHERN PORTIONS OF SAN BERNARDINO AND MOHAVE COUNTIES.
AT THIS TIME...IT APPEARS AS IF COVERAGE WILL BE SIMILAR TO WHAT WAS
OBSERVED YESTERDAY...WITH ACTIVITY AGAIN TAPERING OFF THIS EVENING
WITH THE LOSS OF DAYTIME HEATING. DRY MID-LEVEL AIR WILL AGAIN HELP
TO KEEP AREAS FROM ROUGHLY LAS VEGAS NORTHWARD EFFECTIVELY CAPPED
AGAIN TODAY.
THURSDAY NIGHT INTO FRIDAY...MID TO UPPER LEVEL DRY AIR WILL INTRUDE
THE AREA FROM THE NORTHEAST AS THE CENTER OF THE HIGH SHIFTS
WESTWARD. THIS WILL SCOUR OUT MOISTURE FROM NORTHEAST TO SOUTHWEST
AT MID AND UPPER LEVELS...CONFINING ANY CHANCES FOR THUNDERSTORMS TO
SOUTHWESTERN PORTIONS OF SAN BERNARDINO COUNTY. AFTERNOON HIGH
TEMPERATURES WILL CONTINUE TO RUN ROUGHLY 8-10 DEGREES ABOVE
SEASONAL NORMALS THROUGH SATURDAY AFTERNOON...BEFORE A PATTERN
CHANGE SPELLS A SHARP COOLDOWN AND AN INCREASE IN SHOWER AND
THUNDERSTORM ACTIVITY FROM SUNDAY ONWARD.
.LONG TERM...SUNDAY THROUGH WEDNESDAY.
CONFIDENCE IS INCREASING THAT ABUNDANT REMNANT MOISTURE FROM
DECAYING TROPICAL STORM LINDA WILL SPREAD OVER THE REGION SUNDAY AND
MONDAY. THE OPERATIONAL GFS AND ECMWF ARE NOW IN GENERALLY GOOD
AGREEMENT WITH THE EVOLVING PATTERN. THEY DEPICT THE REMNANT MID
LEVEL MOISTURE FROM LINDA BEING PULLED UP ALONG THE CALIFORNIA COAST
BY A CIRCULATION OVER THE EASTERN PACIFIC...CURRENTLY CENTERED NEAR
30N 135W. AS THIS CIRCULATION APPROACHES THE CENTRAL CALIFORNIA
COAST...IT APPEARS TO INFUSE THE WEAKENING MID LEVEL CIRCULATION
FROM LINDA AND KICK IT INLAND ACROSS SOUTHERN CALIFORNIA AND
SOUTHERN NEVADA SUNDAY. CONSIDERABLE CLOUD COVER AND LIGHT SHOWERS
WILL MOST LIKELY RESULT SUNDAY AS MODEL FORECAST SOUNDINGS INDICATE
ONLY MARGINAL INSTABILITY. SO...HEAVY RAIN PRODUCING THUNDERSTORMS
DO NOT APPEAR AS FAVORABLE AS THEY DO MONDAY...WHEN DEEPER MOISTURE
WILL BE IN PLACE. AN INCREASING SOUTHWEST JET IS FORECAST TO MOVE
OVER SOUTHERN CALIFORNIA AND SOUTHERN NEVADA MONDAY WHILE THE
CIRCULATION THAT MOVED INTO CENTRAL CALIFORNIA PHASES WITH A DEEP
LOW PRESSURE SYSTEM DROPPING INTO THE PACIFIC NORTHWEST. EASTERN SAN
BERNARDINO...CLARK...LINCOLN AND MOHAVE COUNTIES COULD SEE HEAVY
RAIN PRODUCING THUNDERSTORMS WITH SOME MORE ORGANIZED CELLS DUE TO
INCREASING WIND SHEAR. STORM MOTION WILL ALSO INCREASE WHICH WILL BE
A FACTOR WORKING AGAINST THE FLASH FLOOD THREAT. POP VALUES WERE
INCREASED 10-20 PERCENT SUNDAY THROUGH MONDAY DUE TO THE
A BROAD TROUGH IS FORECAST TO BE OVER THE WESTERN STATES TUESDAY AND
SOME DRYING SHOULD OCCUR DUE TO THE SOUTHWEST FLOW.
HOWEVER...LINCOLN AND MOHAVE COUNTIES MAY STILL SEE THE POTENTIAL
FOR SIGNIFICANT THUNDERSTORMS DUE TO LINGERING MOISTURE. WEDNESDAY
SHOULD SEE FURTHER DRYING FROM THE TROUGH WITH DECREASING STORM
COVERAGE. A DEFINITE COOLING TREND WILL OCCUR DUE TO THE
AFOREMENTIONED FACTORS WHICH WAS ALREADY INDICATED IN THE INHERITED
GRIDS. TEMPERATURES WERE DECREASED SLIGHTLY EACH DAY BASED ON THE
LATEST GUIDANCE.
&&
.AVIATION...FOR MCCARRAN...LIGHT WINDS GENERALLY UNDER 8 KTS ARE
EXPECTED TODAY...GENERALLY FROM AN EASTERLY DIRECTION DURING THE DAY
AND SOUTH-SOUTHWEST OVERNIGHT. SHRA/TSRA ARE POSSIBLE MAINLY TO THE
SOUTH OF THE TERMINAL TODAY...WITH A SLIGHT CHANCE OF TSRA
DEVELOPING IN THE MCCULLOUGH RANGE AND/OR SPRING MOUNTAINS LATER
THIS AFTERNOON.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SCATTERED-ISOLATED SHRA/TSRA WILL BE POSSIBLE AGAIN
THIS AFTERNOON PRIMARILY SOUTH OF KLAS. GUSTY AND ERRATIC WINDS WILL
BE POSSIBLE IN AND NEAR ANY SHRA/TSRA. OTHERWISE RELATIVELY LIGHT
WINDS WILL FAVOR TYPICAL DIURNAL TRENDS. EXPECT SCT-BKN CLOUDS AOA
7K-12K FEET AS WELL SOUTH OF LAS VEGAS. AREAS OF FU AND HZ ARE
POSSIBLE IN AROUND KBIH REDUCING VSBY AND CREATING LOCALIZED
MOUNTAIN OBSCURATIONS.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...PULLIN
LONG TERM.............ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1003 AM CDT THU SEP 10 2015
.DISCUSSION...NO CHANGES MADE TO THE MORNING FORECAST PACKAGE.
THERE IS ONGOING CONVECTION ACROSS THE VICTORIA CROSSROADS AREA
THAT IS QUICKLY MOVING TO THE OUT OF THE COUNTY. COULD SEE
ISOLATED AMOUNTS OF 2 TO 3 INCHES POSSIBLE WITH SOME OF THE
SHOWERS/STORMS TODAY WITH 12Z CRP SOUNDING REPORTING 2.24 INCHES.
LAPS ANALYSIS SHOWS AREAS TO THE SOUTH HAVE STABILIZED FROM
EARLIER RAINS...BUT SHOULD SEE THE AREA BECOME UNSTABLE AGAIN
WITH A BIT MORE HEATING. FARTHER SOUTH ACROSS THE SOUTHERN COASTAL
BEND AND EASTERN BRUSH COUNTRY...INSTABILITY HAS INCREASED WITH
NOTICEABLE CU FIELD DEVELOPING ON VISIBLE IMAGERY AND WILL EXPECT
MORE CONVECTIVE DEVELOPMENT ACROSS THIS AREA THROUGH THE LATE
MORNING AND EARLY AFTERNOON HOURS. COVERAGE SHOULD INCREASE ACROSS
THE EASTERN CWA THROUGH THE REST OF THE AFTERNOON HOURS...SLOWLY
PROGRESSING FARTHER WEST INTO THE LATE AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 630 AM CDT THU SEP 10 2015/
DISCUSSION...SEE AVIATION SECTION FOR 12Z TAFS.
AVIATION...PATCHY MVFR CEILINGS EXIST UNDERNEATH CIRRUS OVER THE
REGION...MAINLY NEAR THE COAST AND NORTHERN BRUSH COUNTRY. PATCHY
FOG CONTINUES FROM BEEVILLE TO VICTORIA WITH MVFR VSBYS THAT WILL
LINGER FOR A COUPLE OF MORE HOURS. SCATTERED SHOWERS/THUNDERSTORMS
FORMING IN CONVERGENCE ZONE ALONG THE COAST THIS MORNING WHILE AN
AREA OF SHOWERS PERSISTS NEAR COTULLA. MVFR CIGS WILL PERSIST FOR
THE COASTAL PLAINS THIS MORNING WITH AREAL SHOWERS PROVIDING MVFR
VSBYS. SCATTERED-NUMEROUS SHOWERS AND THUNDERSTORMS WILL BE OVER
THE REGION FROM LATE MORNING THRU THE AFTERNOON. WILL SHOW LOW END
MVFR VSBYS POSSIBLE WITHIN THE T-STORMS BUT IFR VSBYS WILL OCCUR
IN THE STRONGER DOWNPOURS ALONG WITH GUSTY WINDS. EXPECT THE
CONVECTION WILL DIMINISH WITH THE LOSS OF HEATING EARLY IN THE
EVENING. VFR CONDITIONS AFTER 02Z WITH MAINLY MID LEVEL CLOUDS
OVER SOUTH TEXAS THROUGH 06Z. ANOTHER UPPER LEVEL DISTURBANCE
WILL APPROACH THE REGION FROM THE NORTHWEST OVERNIGHT. SCATTERED
CONVECTION IS EXPECTED TO REDEVELOP AROUND 08Z FRIDAY PROVIDING
MVFR VSBYS/CIGS.
PREV DISCUSSION... /ISSUED 425 AM CDT THU SEP 10 2015/
SHORT TERM (TODAY THROUGH FRIDAY)...GOES SOUNDER IMAGE OF
PRECIPITABLE WATER SHOWS A VERY MOIST AIR MASS IN PLACE ACROSS
THE REGION WITH PWAT VALUES BETWEEN 2.3 AND 2.5 INCHES. WATER
VAPOR IMAGERY SHOWS THE TAIL END OF A SHORT WAVE TROUGH FROM
EAST TEXAS EXTENDING WEST INTO CENTRAL TEXAS THIS MORNING.
THIS SHORT WAVE TROUGH WILL MOVE SOUTHEAST TOWARD THE UPPER
TEXAS COAST TODAY. A MODEST UPPER LEVEL JET STREAK IS ROUNDING
THE UPPER RIDGE TO THE WEST AND NOSING DOWN INTO THE HILL
COUNTRY. SCATTERED CONVECTION HAS FORMED NORTH OF COTULLA
EARLY THIS MORNING NEAR THIS UPPER JET FEATURE. THE LATEST
TECH WRF...OOZ NSSL WRF AND 05Z HRRR SHOW THIS ACTIVITY WILL
DIMINISH LATER THIS MORNING WITH ADDITIONAL CONVECTION FORMING
NEAR LOW LEVEL CONVERGENCE ZONE ALONG THE COAST. THE NOSE OF
THE UPPER JET WILL BE OVER THE VICTORIA CROSSROADS TO THE
COASTAL BEND TODAY. SO KEPT LIKELY POPS IN THIS REGION FOR
TODAY WITH CHANCE POPS OVER THE BRUSH COUNTRY. CONVECTION MAY
LINGER OVER THE BRUSH COUNTRY THIS EVENING AS BOUNDARY
INTERACTIONS KEEP ACTIVITY GOING FOR A FEW HOURS AFTER LOSS
OF HEATING. THERE SHOULD BE A BRIEF LULL IN ACTIVITY LATE THIS
EVENING...BUT ANOTHER SHORT WAVE TROUGH WILL BE APPROACHING THE
AREA FROM THE NORTHWEST AFTER MIDNIGHT. MODELS SUGGEST SCATTERED
CONVECTION WILL FORM OVERNIGHT AHEAD OF THIS FEATURE. THE UPPER
LEVEL JET STREAK MOVES TOWARD SOUTHEAST TEXAS ON FRIDAY WITH
WEAKLY DIFLUENT UPPER FLOW OVER THE REGION. WITH DEEP MOISTURE
REMAINING OVER SOUTH TEXAS...LOOKS LIKE MOST OF THE AREA WILL HAVE
A GOOD CHANCE TO SEE ADDITIONAL RAINFALL FROM SCATTERED TO
NUMEROUS CONVECTION FRIDAY. WENT LIKELY POPS FOR ENTIRE AREA ON
FRIDAY WITH MAX TEMPERATURES IN THE UPPER 80S EAST TO LOWER 90S
WEST.
LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...MOISTURE FROM WEAK
SURFACE BOUNDARY WILL BE SINKING INTO DEEP SOUTH TEXAS AT THE
BEGINNING OF LONG TERM PERIOD. HAVE CHANCE TO LIKELY POPS REMAINING
FRIDAY NIGHT...THEN DECREASING ON SATURDAY. DRIER CONDITIONS ARE
EXPECTED FOR SUNDAY AS HIGH PRESSURE RIDGE BRIEFLY BUILDS ACROSS THE
REGION. EARLY NEXT WEEK MOISTURE RETURNS TO THE AREA AS A COASTAL
TROUGH DEVELOPS IN ALONG THE GULF COAST. MODELS DIFFER SIGNIFICANTLY
ON THE DETAILS OF THIS TROUGH...BUT BOTH GFS AND ECMWF INDICATE
INCREASING CHANCES FOR SHOWERS AND STORMS TUESDAY AND WEDNESDAY.
THERE IS SOME TREND TO KEEP THE MAJORITY OF THE RAINFALL IN THE
MARINE AREAS...BUT WILL HOLD ONTO CHANCE POPS IN THE COASTAL BEND
AND BRUSH COUNTRY TEMPERATURES SHOULD BE SLIGHTLY BELOW NORMAL OVER
THE WEEKEND AND INTO EARLY NEXT WEEK...THEN GRADUALLY WARM BACK TO
NEAR NORMAL BY WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 92 77 89 74 88 / 60 40 60 50 40
VICTORIA 90 74 88 71 86 / 60 40 60 30 20
LAREDO 99 78 93 73 89 / 40 40 60 50 40
ALICE 94 75 91 72 89 / 60 40 60 50 40
ROCKPORT 90 78 88 74 87 / 60 50 60 50 40
COTULLA 95 75 91 72 91 / 50 40 60 30 20
KINGSVILLE 93 76 90 73 88 / 60 40 60 50 40
NAVY CORPUS 90 79 87 75 86 / 60 50 60 50 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
CB/85...SHORT TERM
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
630 AM CDT THU SEP 10 2015
.DISCUSSION...SEE AVIATION SECTION FOR 12Z TAFS.
&&
.AVIATION...PATCHY MVFR CEILINGS EXIST UNDERNEATH CIRRUS OVER THE
REGION...MAINLY NEAR THE COAST AND NORTHERN BRUSH COUNTRY. PATCHY
FOG CONTINUES FROM BEEVILLE TO VICTORIA WITH MVFR VSBYS THAT WILL
LINGER FOR A COUPLE OF MORE HOURS. SCATTERED SHOWERS/THUNDERSTORMS
FORMING IN CONVERGENCE ZONE ALONG THE COAST THIS MORNING WHILE AN
AREA OF SHOWERS PERSISTS NEAR COTULLA. MVFR CIGS WILL PERSIST FOR
THE COASTAL PLAINS THIS MORNING WITH AREAL SHOWERS PROVIDING MVFR
VSBYS. SCATTERED-NUMEROUS SHOWERS AND THUNDERSTORMS WILL BE OVER
THE REGION FROM LATE MORNING THRU THE AFTERNOON. WILL SHOW LOW END
MVFR VSBYS POSSIBLE WITHIN THE T-STORMS BUT IFR VSBYS WILL OCCUR
IN THE STRONGER DOWNPOURS ALONG WITH GUSTY WINDS. EXPECT THE
CONVECTION WILL DIMINISH WITH THE LOSS OF HEATING EARLY IN THE
EVENING. VFR CONDITIONS AFTER 02Z WITH MAINLY MID LEVEL CLOUDS
OVER SOUTH TEXAS THROUGH 06Z. ANOTHER UPPER LEVEL DISTURBANCE
WILL APPROACH THE REGION FROM THE NORTHWEST OVERNIGHT. SCATTERED
CONVECTION IS EXPECTED TO REDEVELOP AROUND 08Z FRIDAY PROVIDING
MVFR VSBYS/CIGS.
&&
.PREV DISCUSSION... /ISSUED 425 AM CDT THU SEP 10 2015/
SHORT TERM (TODAY THROUGH FRIDAY)...GOES SOUNDER IMAGE OF
PRECIPITABLE WATER SHOWS A VERY MOIST AIR MASS IN PLACE ACROSS
THE REGION WITH PWAT VALUES BETWEEN 2.3 AND 2.5 INCHES. WATER
VAPOR IMAGERY SHOWS THE TAIL END OF A SHORT WAVE TROUGH FROM
EAST TEXAS EXTENDING WEST INTO CENTRAL TEXAS THIS MORNING.
THIS SHORT WAVE TROUGH WILL MOVE SOUTHEAST TOWARD THE UPPER
TEXAS COAST TODAY. A MODEST UPPER LEVEL JET STREAK IS ROUNDING
THE UPPER RIDGE TO THE WEST AND NOSING DOWN INTO THE HILL
COUNTRY. SCATTERED CONVECTION HAS FORMED NORTH OF COTULLA
EARLY THIS MORNING NEAR THIS UPPER JET FEATURE. THE LATEST
TECH WRF...OOZ NSSL WRF AND 05Z HRRR SHOW THIS ACTIVITY WILL
DIMINISH LATER THIS MORNING WITH ADDITIONAL CONVECTION FORMING
NEAR LOW LEVEL CONVERGENCE ZONE ALONG THE COAST. THE NOSE OF
THE UPPER JET WILL BE OVER THE VICTORIA CROSSROADS TO THE
COASTAL BEND TODAY. SO KEPT LIKELY POPS IN THIS REGION FOR
TODAY WITH CHANCE POPS OVER THE BRUSH COUNTRY. CONVECTION MAY
LINGER OVER THE BRUSH COUNTRY THIS EVENING AS BOUNDARY
INTERACTIONS KEEP ACTIVITY GOING FOR A FEW HOURS AFTER LOSS
OF HEATING. THERE SHOULD BE A BRIEF LULL IN ACTIVITY LATE THIS
EVENING...BUT ANOTHER SHORT WAVE TROUGH WILL BE APPROACHING THE
AREA FROM THE NORTHWEST AFTER MIDNIGHT. MODELS SUGGEST SCATTERED
CONVECTION WILL FORM OVERNIGHT AHEAD OF THIS FEATURE. THE UPPER
LEVEL JET STREAK MOVES TOWARD SOUTHEAST TEXAS ON FRIDAY WITH
WEAKLY DIFLUENT UPPER FLOW OVER THE REGION. WITH DEEP MOISTURE
REMAINING OVER SOUTH TEXAS...LOOKS LIKE MOST OF THE AREA WILL HAVE
A GOOD CHANCE TO SEE ADDITIONAL RAINFALL FROM SCATTERED TO
NUMEROUS CONVECTION FRIDAY. WENT LIKELY POPS FOR ENTIRE AREA ON
FRIDAY WITH MAX TEMPERATURES IN THE UPPER 80S EAST TO LOWER 90S
WEST.
LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...MOISTURE FROM WEAK
SURFACE BOUNDARY WILL BE SINKING INTO DEEP SOUTH TEXAS AT THE
BEGINNING OF LONG TERM PERIOD. HAVE CHANCE TO LIKELY POPS REMAINING
FRIDAY NIGHT...THEN DECREASING ON SATURDAY. DRIER CONDITIONS ARE
EXPECTED FOR SUNDAY AS HIGH PRESSURE RIDGE BRIEFLY BUILDS ACROSS THE
REGION. EARLY NEXT WEEK MOISTURE RETURNS TO THE AREA AS A COASTAL
TROUGH DEVELOPS IN ALONG THE GULF COAST. MODELS DIFFER SIGNIFICANTLY
ON THE DETAILS OF THIS TROUGH...BUT BOTH GFS AND ECMWF INDICATE
INCREASING CHANCES FOR SHOWERS AND STORMS TUESDAY AND WEDNESDAY.
THERE IS SOME TREND TO KEEP THE MAJORITY OF THE RAINFALL IN THE
MARINE AREAS...BUT WILL HOLD ONTO CHANCE POPS IN THE COASTAL BEND
AND BRUSH COUNTRY TEMPERATURES SHOULD BE SLIGHTLY BELOW NORMAL OVER
THE WEEKEND AND INTO EARLY NEXT WEEK...THEN GRADUALLY WARM BACK TO
NEAR NORMAL BY WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 92 77 89 74 88 / 60 40 60 50 40
VICTORIA 90 74 88 71 86 / 60 40 60 30 20
LAREDO 99 78 93 73 89 / 40 40 60 50 40
ALICE 94 75 91 72 89 / 60 40 60 50 40
ROCKPORT 90 78 88 74 87 / 60 50 60 50 40
COTULLA 95 75 91 72 91 / 50 40 60 30 20
KINGSVILLE 93 76 90 73 88 / 60 40 60 50 40
NAVY CORPUS 90 79 87 75 86 / 60 50 60 50 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TMT/89...AVIATION
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
556 AM CDT THU SEP 10 2015
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...LIGHT SOUTHEAST WINDS WITH A FEW PASSING CLOUDS
PREVAIL OVER DEEP SOUTH TEXAS THIS MORNING. SOME PATCHY LIGHT FOG
AND LOW CLOUD DECKS HAVE BEEN OBSERVED ACROSS THE REGION IN THE
PAST COUPLE OF HOURS. BRIEF MVFR CONDITIONS WILL BE POSSIBLE JUST
AFTER SUNRISE. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH THIS
LATE EVENING. WILL KEEP THE MENTION OF VCSH AT ALL TAF SITES AS
ISOLATED SEA BREEZE ACTIVITY IS POSSIBLE LATER TODAY. LIGHT
SOUTHEAST WINDS WILL BECOME MODERATE LATER THIS MORNING WITH GUSTS
AROUND 20 KNOTS IN THE AFTERNOON. WINDS WILL GRADUALLY WEAKEN THIS
EVENING WITH INCREASING LOW CLOUDS LATE TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 422 AM CDT THU SEP 10 2015/
SHORT TERM /NOW THROUGH FRIDAY/...LATEST WATER VAPOR SATELLITE
IMAGERY SHOWS A 500MB RIDGE CENTERED OVER WEST TEXAS INTO NORTHERN
MEXICO AND OVER SOUTH FLORIDA WITH 500MB WEAKNESS OVER THE WESTERN
GULF OF MEXICO. BROWNSVILLE RADAR SHOWS ISOLATED ACTIVITY ACROSS THE
LOWER TEXAS GULF WATERS THIS MORNING. THE LATEST HRRR SUGGESTS
CONVECTION WILL INCREASE ACROSS THE GULF WATERS THROUGH SUNRISE. BRO
SOUNDING FROM WEDNESDAY EVENING INDICATES PRECIPITABLE WATER VALUES
OF 1.87 INCHES. EXCEPT FOR SOME PASSING HIGH CLOUDS...MOSTLY CLEAR
SKIES AND LIGHT WINDS PREVAIL ACROSS DEEP SOUTH TEXAS EARLY THIS
MORNING. A LITTLE GROUND FOG MAY DEVELOP AROUND SUNRISE BEFORE
QUICKLY DISSIPATING. NOTE...THE SURFACE OBSERVATION FROM EDINBURG IS
NOT REPRESENTATIVE TO CURRENT WEATHER CONDITIONS.
THE MAIN FORECAST ISSUE WILL BE THE RAIN CHANCES ACROSS DEEP SOUTH
TEXAS THROUGH THE FORECAST PERIOD. DEEP TROPICAL MOISTURE
/PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES/ COMBINED WITH DAY
TIME HEATING WILL SUPPORT ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS TODAY. HIGH TEMPERATURES TODAY WILL RANGE FROM THE
LOWER 90S NEAR THE COAST TO THE UPPER 90S ACROSS THE UPPER VALLEY.
RAIN CHANCES MAY LINGER ACROSS THE NORTHERN RANCHLANDS TONIGHT AS
THE GFS SUGGESTS. OTHERWISE...MOSTLY CLOUDY SKIES WITH LOW
TEMPERATURES GENERALLY IN THE MID TO UPPER 70S. THE HIGHEST RAIN
CHANCES WILL BE FRIDAY WITH PRECIPITABLE WATERS BETWEEN 2.2 TO 2.5
INCHES PER THE LATEST NAM/GFS. HIGH TEMPERATURES FRIDAY WILL BE A
FEW DEGREES LOWER DUE TO THE INCREASE IN RAIN CHANCES AND CLOUD
COVER.
ANY OF THE HEAVIER OR SLOWER-MOVING SHOWERS AND THUNDERSTORMS TODAY
AND FRIDAY WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL
WITH NUISANCE FLOODING ON ROADS AND IN LOW-LYING AREAS...ESPECIALLY
THOSE WITH A HISTORY OF FLOODING.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...ACTIVE WEATHER
PATTERN REMAINS FOR THE LONG TERM PORTION OF THE FORECAST. WEAK
COLD FRONT PASSES THROUGH THE BRO CWFA FRIDAY NIGHT...WITH
INVERTED SURFACE TROUGHINESS FORMING AND PERSISTING ALONG THE
LOWER TEXAS COAST AFTERWARDS. SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ARE FORECAST FOR FRIDAY NIGHT THROUGH SUNDAY...
WITH LOCALLY HEAVY RAINFALL POSSIBLE FRIDAY NIGHT AND SATURDAY
WITH DEEP TROPICAL MOISTURE IN PLACE. CONVECTION WILL BECOME MORE
ISOLATED SUNDAY NIGHT THROUGH THE END OF THE FORECAST AS THE FOCUS
OF THE ACTIVITY SHIFTS MORE OFFSHORE WITH WEAK LOW PRESSURE
POSSIBLY ATTEMPTING TO FORM OVER THE WESTERN GULF OF MEXICO.
TEMPERATURES WILL BE TEMPERED EARLY IN THE FORECAST PERIOD
COURTESY OF THE INCREASED CLOUDINESS AND OPPORTUNITIES FOR
RAINFALL...BUT SHOULD WARM UP TOWARDS THE MIDDLE AND END OF THE
FORECAST WITH LESSER CHANCES OF RAIN IN PLACE.
MARINE...NOW THROUGH FRIDAY...BUOY DATA AND OBSERVATION PLATFORMS
ALONG THE LOWER TEXAS COAST THIS MORNING INDICATE SOUTH WINDS BETWEEN
8 TO 13 KNOTS WITH SEA HEIGHTS NEAR 3 FEET ON THE GULF WATERS. A
WEAK PRESSURE GRADIENT ALONG THE LOWER TEXAS COAST WILL MAINTAIN
LIGHT TO MODERATE SOUTH TO SOUTHEAST WINDS AND LOW TO MODERATE
SEAS. HOWEVER...SMALL CRAFT WILL NEED TO EXERCISE CAUTION ON THE
LAGUNA MADRE THIS AFTERNOON DUE TO A SLIGHTLY STRONGER WINDS.
FRIDAY NIGHT THROUGH WEDNESDAY...LIGHT TO MODERATE WINDS AND LOW
TO MODERATE SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST THROUGH
EARLY NEXT WEEK AS A WEAK COLD FRONT PASSES THROUGH FRIDAY NIGHT
AND WEAK LOW PRESSURE PERSISTS AFTERWARDS. MARINE CONDITIONS NEAR
THE END OF THE FORECAST PERIOD ARE DEPENDENT ON THE DEVELOPMENT...
IF ANY...OF A WEAK AREA OF LOW PRESSURE OVER THE WESTERN GULF OF
MEXICO.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
63
AREA FORECAST DISCUSSION
NWS TAUNTON MA
702 PM EDT THU SEP 10 2015
.SYNOPSIS...
A FRONT WILL PUSH NORTH OVERNIGHT AND PROVIDE A FOCUS FOR LOCALLY
HEAVY DOWNPOURS OVERNIGHT. LOW PRESSURE FROM THE MID-ATLANTIC WILL
MOVE NORTHEAST ALONG THE FRONT PAST OUR AREA FRIDAY MORNING PULLING
IT OUT TO SEA FOLLOWED BY WEAK HIGH PRESSURE THAT BRINGS A LULL IN
THE WEATHER SATURDAY. WET-WEATHER RETURNS FOR SUNDAY BUT NOT A WASH-
OUT. TURNING DRY AND WARMER INTO NEXT WEEK. POSSIBLE RECORD BREAKING
HEAT INTO MID- TO LATE-SEPTEMBER AS ABOVE-AVERAGE TEMPS ARE FORECAST.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
7 PM UPDATE...
TWO AREAS OF FOCUS. THE FIRST IS ACROSS THE INTERIOR. INDICATIONS
OF MID-LEVEL FRONTOGENESIS WILL BE ONGOING DURING THE OVERNIGHT
HOURS. CAN SEE SOMEWHAT OF A BANDING SIGNATURE WITHIN THE BROADER
RADAR LOOP MOVING INTO NEW ENGLAND FROM THE MID- TO UPPER-HUDSON
VALLEY REGION OF NY. A FOCUS OF HIGHER PWAT OF NEARLY 2-INCHES AND
THERE IS STILL THE LIKELIHOOD OF HEAVY RAIN ACROSS INTERIOR AREAS
OF S NEW ENGLAND TO WARRANT THE FLASH FLOOD WATCH. FEEL THERE WILL
BE A SQUEEZE...BUT DISPLACED FROM THE MORE FAVORABLE REGIONS OF
THE RIGHT-REAR-QUADRANT OF THE UPPER-LEVEL-JET TO THE N...MAY NOT
SEE SIGNIFICANT DEEP-LAYER LIFT. FOCUSED ACTIVITY LOOKS TO BE THE
RESULT OF CONVERGENCE POTENTIALLY SUPPORTED BY VENTING ALOFT IN
ADDITION TO FALLING HEIGHTS.
SECOND AREA OF FOCUS IS OVER SE NEW ENGLAND. HIGHER THETA-E AIR
AND ACCOMPANYING INSTABILITY AXIS. THIS IS WHERE LIKELY THUNDER
WILL PROCEED DURING THE OVERNIGHT HOURS WITHIN THE ANTICYCLONIC
BRANCH OF THE WARM-MOIST CONVEYOR BELT AS SYNOPTICALLY THIS IS AN
OPEN-WAVE SYSTEM. NO REASON TO BELIEVE THIS WILL CURTAIL BACK
CYCLONICALLY TOWARDS THE INTERIOR. PARENT WITH A H925-85 LOW-
LEVEL-JET AND AREAS OF CONVERGENCE...THE HEAVIEST RAIN AND THE
STRONGEST OF ACTIVITY LOOKS TO OCCUR HERE. MAY HAVE TO EXTEND THE
FLASH FLOOD WATCH FOR SE NEW ENGLAND INTO THE MORNING HOURS. WILL
LET THE OVERNIGHT CREW EVALUATE AND DECIDE TOWARDS THE EXPIRATION.
OVERALL...A WELCOMING RAINFALL AS MUCH OF THE AREA HAS BEEN DRY
SINCE MID-AUGUST. D0-D1 ABNORMAL TO MODERATE DROUGHT CONDITIONS
HAVE BEEN FLAGGED ACROSS THE REGION. THIS BENEFICIAL RAIN SHOULD
EASE SUCH DRY CONDITIONS AND BRING RESERVOIRS AND STREAMFLOWS BACK
UP TO NEAR-NORMAL LEVELS.
WILL KEEP IT MILD OVERNIGHT WITH THE LIKELIHOOD OF PATCHY FOG
AND/OR LOW VISIBILITIES WITH ANY HEAVY RAIN ESPECIALLY ACROSS THE
S/SE-COAST WITH HIGHER DEWPOINT AIR IN THE UPPER-60S TO LOW-70S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
COASTAL LOW PRESSURE MOVES OFF TO THE EAST FRIDAY MORNING...CARRYING
ANY REMAINING PCPN OFF TO THE EAST. MODEL MOISTURE FIELDS SHOW
DRYING FROM WEST TO EAST DURING THE DAY...SUGGESTING A CLEARING
TREND FRIDAY AFTERNOON INTO FRIDAY NIGHT.
MEANWHILE...A LARGER UPPER SHORTWAVE DIGS OVER THE GREAT LAKES AND
MAINTAINS A SOUTHWEST FLOW ALOFT. THE SUPPORTING UPPER JET WILL BE
POSITIONED OVER THE EASTERN GREAT LAKES...GENERATING MORE CONVECTION
IN THAT AREA WHILE NEW ENGLAND HAS WEAK SUBSIDENCE. SO FRIDAY
AFTERNOON AND NIGHT SHOULD BE A DRY PERIOD. NORTH WIND FRIDAY WILL
DIMINISH FRIDAY NIGHT INLAND.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
*/ HIGHLIGHTS...
- KEEPING IT DRY ON SATURDAY
- WET WEATHER FOR SUNDAY BUT NOT LOOKING LIKE A WASHOUT EVERYWHERE
- HEAVY RAIN THOUGH MAY IMPACT SE NEW ENGLAND ... HIGH TERRAIN
- DRY AND WARM INTO NEXT WEEK ... POSSIBLE RECORD BREAKING HEAT
*/ DISCUSSION...
KEEPING WITH AN ENSEMBLE APPROACH. H5 DEEP-TROUGH CLOSED LOW SWEEPS
THROUGH THE OHIO-RIVER VALLEY SATURDAY AHEAD OF WHICH THERE IS RIDGE-
AMPLIFICATION KEEPING US MOSTLY DRY WITH LIKELY SOME MID-HIGH LEVEL
CLOUDS ACROSS THE REGION. LIFTING E SUNDAY DIFFLUENCE PROCEEDS ABOVE
LOW-MID LEVEL LIFT / CONVERGENCE BUT CONVINCED S NEW ENGLAND IS IN
AN AREA OF LESS FAVORABLE DEVELOPMENT. TWO AREAS OF INTEREST: THE
CYCLONIC TROWALING ROUND THE CLOSED LOW BACK INTO THE E GREAT LAKES
WHERE DEFORMATION PROCEEDS...AND SE NEW ENGLAND AND POINTS OFFSHORE
WITHIN THE ANTI-CYCLONIC BRANCH OF THE WARM CONVEYOR BELT WHERE HIGH
THETA-E VALUES RESIDE BENEATH DIFFLUENCE AND ENHANCED ASCENT WITH
CONVERGENCE ALONG A STRONG H925-7 JET. S NEW ENGLAND BELOW THE RIGHT-
FRONT-QUADRANT OF THE UPPER-LEVEL-JET AND IN THE CROSS-HAIRS OF A
MID-LEVEL DRY-PUNCH WRAPPING INTO THE OCCLUDING SYSTEM PER ENSEMBLE
MEANS LOOKS TO RESULT IN LITTLE OUTCOME OVER THE AREA. IN OTHER
WORDS...NOT APPEARING TO BE A WASHOUT ON SUNDAY. CAN NOT RULE OUT
HIGHER AMOUNTS OVER THE HIGHER TERRAIN.
WITH ENSEMBLES LIFTING THE TROWAL N OF THE REGION SUNDAY NIGHT INTO
MONDAY...LESS CONFIDENCE OF OUTCOMES ON MONDAY BENEATH THE COLD POOL
AS THE TROUGH MAY MOVE THRU PRIOR TO BOUNDARY-LAYER DESTABILIZATION.
PERHAPS SOME ACTIVITY UP AGAINST THE W-SLOPES OF HIGHER TERRAIN N OF
OUR AREA WITH W-WIND CONVERGENCE.
FOR THE REMAINDER OF THE WEEK...CONSISTENT SIGNALS OF RIDGING. THINK
HEAT AND HUMIDITY BUILD BACK INTO THE REGION. AGREE WITH THE CLIMATE
PREDICTION CENTER WITH ABOVE-AVERAGE TEMPERATURES. ENSEMBLES SIGNAL
ANOMALOUS H85 TEMPERATURES ACROSS THE REGION. THINKING THAT WE COULD
BREAK SOME RECORD HIGH TEMPERATURES INTO MID- TO LATE-SEPTEMBER.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...
TONIGHT...MODERATE CONFIDENCE.
CONFIDENT MVFR-VLIFR MIX WITH CIGS. LOWER CONFIDENCE WITH VSBYS
BUT EXPECT IFR WITH RA/+RA. FOG ALONG WITH LIFR-VLIFR CIGS LIKELY
AN ISSUE FOR S/SE-COASTAL TERMINALS ALONG WITH A GREATER PROPENSITY
OF FOG. WILL LEAN HIGHER TSRA CHANCES TOWARDS THE S/SE-COASTAL
TERMINALS PREVAILING WITH VCTS. E/NE-WINDS BACKING OUT OF THE N
TOWARDS MORNING.
FRIDAY...MODERATE CONFIDENCE.
IMPROVEMENT BEGINNING DURING THE MORNING TOWARDS VFR. NE-WINDS
INCREASING AND GUSTING TO 20 KTS ALONG THE COASTS.
FRIDAY NIGHT...HIGH CONFIDENCE.
EXPECT MVFR-LIFR FOG DEVELOPMENT ESPECIALLY OVER THE INTERIOR
TOWARDS MORNING. TYPICALLY PRONE TERMINALS WITHIN SHELTERED
VALLEYS LIKELY TO EXPERIENCE LIGHT WINDS OVERNIGHT LIKE THE CT-
RIVER VALLEY ESPECIALLY PRONE.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. WILL KEEP THUNDER OUT
OF THE TAF OVERNIGHT EXPECTING IT TO REMAIN E/SE OFFSHORE.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY...HIGH CONFIDENCE.
VFR. WINDS VEERING E/SE. A MAINLY DRY FORECAST.
SATURDAY NIGHT - SUNDAY NIGHT...MODERATE CONFIDENCE.
MVFR-IFR MIX WITH E/SE-ONSHORE FLOW BACKING SW TOWARDS THE END OF
THE FORECAST PERIOD. RAIN LIKELY ACROSS THE REGION. PATCHY FOG
POSSIBLE. MAY ALSO CONTEND WITH SOME LLWS IMPACTS.
MONDAY INTO TUESDAY...MODERATE CONFIDENCE.
VFR. W/SW-WINDS WITH GUSTS UP TO 20 KTS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE IN TRENDS.
MODERATE CONFIDENCE IN SPECIFIC TIMING.
7 PM UPDATE...NO MAJOR CHANGES.
TONIGHT...INCREASING COVERAGE IN SHOWERS AND THUNDERSTORMS.
LOCALLY HEAVY DOWNPOURS POSSIBLE. AREAS OF POOR VISIBILITY IN FOG
ESPECIALLY AROUND NANTUCKET
FRIDAY...LOW PRESSURE LIFTING NE ACROSS THE WATERS. SHOWERS AND
AREAS OF FOG START THE DAY. INCREASING NORTH WINDS WILL REACH 20
KNOTS ON OUR EASTERN WATERS AND COULD GET AS STRONG AS 25 KT. THE
N-NE FETCH SHOULD BE ENOUGH TO BUILD SEAS ON THE EXPOSED EASTERN
WATERS TO 5 FEET...POSSIBLY 6. A SMALL CRAFT ADVISORY HAS BEEN
POSTED ON THE OUTER WATERS AND IN MASS BAY...PRIMARILY FOR SEAS
BUT WITH AN EYE TOWARD THE WINDS AS WELL.
FRIDAY NIGHT...MODERATE CONFIDENCE.
DIMINISHING NORTH TO NORTHWEST WINDS WITH SEAS SUBSIDING AFTER
MIDNIGHT.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY...MODERATE CONFIDENCE.
A LULL IN THE WEATHER. WINDS BECOME LIGHT WHILE VEERING E/SE. SHOULD
SEE SEAS SUBSIDE FOR THE PERIOD BELOW 5-FEET.
SUNDAY...MODERATE CONFIDENCE.
DEEPER AREA OF LOW PRESSURE TO THE W. WILL SEE AN ACCOMPANYING WARM
FRONT LIFT N ACROSS THE WATERS BRINGING WITH IT RAIN ALONG WITH
INCREASING E/SE-ONSHORE WINDS. GUSTS UP TO 20 KTS. WAVE HEIGHTS
BUILDING IN EXCESS OF 5-FEET INITIALLY OVER THE S WATERS EXPANDING
TO THE E/SE WATERS LATE IN THE PERIOD.
MONDAY...MODERATE CONFIDENCE.
IMPROVING. WINDS BACK OUT OF THE W/SW AND REMAIN ROBUST WITH A
STRONG AREA OF LOW PRESSURE SITUATED WELL TO THE W ACROSS THE
INTERIOR. ANOTHER DAY OF GUSTS UP TO 20 KTS WHILE SEAS REMAIN AT OR
IN EXCESS OF 5-FEET ON THE WATERS.
&&
.HYDROLOGY...
7 PM UPDATE...
RAINFALL RATES TODAY HAVE BEEN EFFICIENT AT TIMES WITH 2 TO 4
INCHES PER HOUR. FEEL THIS RISK PERSISTS THROUGH THE OVERNIGHT
ESPECIALLY THOSE AREAS OF HIGHER THETA-E WHICH ARE FORECAST TO
PREVAIL OVER SE NEW ENGLAND. NEVERTHELESS...CONVERGENCE ALONG A
FRONTAL BOUNDARY OVER THE INTERIOR OF A 2-INCH PWAT AIRMASS IS
LIKELY TO LEAD TO LOCALIZE EFFICIENCY OF HEAVY RAIN. NOT ABSOLUTELY
CERTAIN ON THE SPECIFICS AS TO WHERE...BUT A SW-NE BAND IS EXPECTED
ACROSS THE INTERIOR WARRANTING THE CONTINUATION OF THE FLASH FLOOD
WATCH.
WITH SE NEW ENGLAND UNDER THE FAVORABLE ENVIRONMENT OF HIGHER
THETA-E AIR ACCOMPANIED WITH INSTABILITY AND A LOW-LEVEL-JET AND
AREAS OF LOCALIZED CONVERGENCE...THE PROPENSITY FOR HEAVY RAIN
ALONG WITH THUNDERSTORMS IS GREATER. MAY NEED TO EXPAND THE FLASH
FLOOD WATCH FOR SE NEW ENGLAND PAST MIDNIGHT INTO THE MORNING
HOURS. WILL ALLOW THE OVERNIGHT SHIFT TO RE-EVALUATE AND AMEND AS
NECESSARY.
EFFICIENT HEAVY RAINFALL PRODUCERS AS WE HAVE SEEN EARLIER TODAY
LEAD TO FLASH FLOODING...ESPECIALLY MORE SO NOW FOR AREAS THAT
HAVE ALREADY BECOME WELL-SATURATED FOR THE DAY. SUBSEQUENTLY THIS
EMPHASIZES THE NECESSARY CONTINUATION OF THE FLASH FLOOD WATCH.
SEE THE UPDATED DISCUSSION AT THE TOP OF THE AFD FOR FURTHER DETAILS.
NEAR-TERM HIGH-RES GUIDANCE SUCH AS THE HRRR AND RAP WERE UTILIZED
IN MAKING THE DETERMINATIONS TO THE FORECAST OVER THE NEXT 12 HOURS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...FLASH FLOOD WATCH UNTIL 6 AM EDT FRIDAY FOR CTZ002>004.
MA...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR MAZ017>022.
FLASH FLOOD WATCH UNTIL 6 AM EDT FRIDAY FOR MAZ002>016-026.
RI...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR RIZ002>007.
FLASH FLOOD WATCH UNTIL 6 AM EDT FRIDAY FOR RIZ001.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM FRIDAY TO 6 AM EDT SATURDAY FOR
ANZ250-254.
SMALL CRAFT ADVISORY FROM 5 AM TO 4 PM EDT FRIDAY FOR ANZ251.
SMALL CRAFT ADVISORY FROM 2 PM FRIDAY TO 2 AM EDT SATURDAY FOR
ANZ255-256.
&&
$$
SYNOPSIS...WTB/SIPPRELL
NEAR TERM...WTB
SHORT TERM...WTB
LONG TERM...SIPPRELL
AVIATION...WTB/SIPPRELL
MARINE...WTB/SIPPRELL
HYDROLOGY...SIPPRELL/FRANK/WTB
AREA FORECAST DISCUSSION
NWS TAUNTON MA
353 PM EDT THU SEP 10 2015
.SYNOPSIS...
A FRONT STALLED ALONG THE SOUTHERN NEW ENGLAND SOUTH COAST WILL
PUSH NORTH OVERNIGHT AND PROVIDE A FOCUS FOR LOCALLY HEAVY
DOWNPOURS DURING THE NIGHT. LOW PRESSURE FROM THE MID ATLANTIC
STATES WILL MOVE NORTHEAST PAST OUR AREA FRIDAY MORNING. WEAK
HIGH PRESSURE THEN BRINGS A LULL IN THE WEATHER SATURDAY. WET-
WEATHER RETURNS FOR SUNDAY BUT NOT APPEARING TO BE A WASHOUT.
PERHAPS SOME HEAVY RAIN FOR THE HIGH TERRAIN AND SOUTHEAST NEW
ENGLAND. TURNING DRY AND WARMER INTO NEXT WEEK. COULD BE LOOKING
AT THE POSSIBILITY OF RECORD BREAKING HEAT INTO MID- TO LATE-
SEPTEMBER AS ABOVE-AVERAGE TEMPS ARE FORECAST.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A COLD FRONT LIES NORTH OF NANTUCKET BUT SOUTH OF THE REMAINDER OF
NEW ENGLAND AND LONG ISLAND. SOUTHWEST FLOW ALOFT HAS A FAINT
SHORTWAVE MOVING THROUGH WITH LOW LEVEL FLOW DRAWING VERY MOST AIR
NORTH OVER THE TOP OF THE FRONT. PRECIPITABLE WATER VALUES
CONTINUE EITHER SIDE OF 2 INCHES...WHICH IS ABOUT AS HIGH AS IT
GETS IN SOUTHERN NEW ENGLAND IN SEPTEMBER.
THE SURFACE FRONT SUPPORTS LOW LEVEL CONVERGENCE AND THE UPPER
SHORTWAVE SUPPORTS UPPER VENTING...AND THIS WILL BE WORKING ON A
VERY JUICY AIRMASS. WE WILL CONTINUE WITH CATEGORICAL POPS FOR
SHOWERS/SCATTERED TSTMS THIS EVENING AND TONIGHT. BASED ON THE
HIGH PW AIR...WE CONTINUE TO EXPECT LOCALLY HEAVY DOWNPOURS THAT
WILL BRING LOCALLY HEAVY DOWNPOURS. BEST CHANCE WILL BE WITH THE
BEST LIFT ALONG AND NORTH OF THE FRONT.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
COASTAL LOW PRESSURE MOVES OFF TO THE EAST FRIDAY
MORNING...CARRYING ANY REMAINING PCPN OFF TO THE EAST. MODEL
MOISTURE FIELDS SHOW DRYING FROM WEST TO EAST DURING THE
DAY...SUGGESTING A CLEARING TREND FRIDAY AFTERNOON INTO FRIDAY
NIGHT.
MEANWHILE...A LARGER UPPER SHORTWAVE DIGS OVER THE GREAT LAKES AND
MAINTAINS A SOUTHWEST FLOW ALOFT. THE SUPPORTING UPPER JET WILL BE
POSITIONED OVER THE EASTERN GREAT LAKES...GENERATING MORE CONVECTION
IN THAT AREA WHILE NEW ENGLAND HAS WEAK SUBSIDENCE. SO FRIDAY
AFTERNOON AND NIGHT SHOULD BE A DRY PERIOD. NORTH WIND FRIDAY WILL
DIMINISH FRIDAY NIGHT INLAND.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
*/ HIGHLIGHTS...
- KEEPING IT DRY ON SATURDAY
- WET WEATHER FOR SUNDAY BUT NOT LOOKING LIKE A WASHOUT EVERYWHERE
- HEAVY RAIN THOUGH MAY IMPACT SE NEW ENGLAND ... HIGH TERRAIN
- DRY AND WARM INTO NEXT WEEK ... POSSIBLE RECORD BREAKING HEAT
*/ DISCUSSION...
KEEPING WITH AN ENSEMBLE APPROACH. H5 DEEP-TROUGH CLOSED LOW SWEEPS
THROUGH THE OHIO-RIVER VALLEY SATURDAY AHEAD OF WHICH THERE IS RIDGE-
AMPLIFICATION KEEPING US MOSTLY DRY WITH LIKELY SOME MID-HIGH LEVEL
CLOUDS ACROSS THE REGION. LIFTING E SUNDAY DIFFLUENCE PROCEEDS ABOVE
LOW-MID LEVEL LIFT / CONVERGENCE BUT CONVINCED S NEW ENGLAND IS IN
AN AREA OF LESS FAVORABLE DEVELOPMENT. TWO AREAS OF INTEREST: THE
CYCLONIC TROWALING ROUND THE CLOSED LOW BACK INTO THE E GREAT LAKES
WHERE DEFORMATION PROCEEDS...AND SE NEW ENGLAND AND POINTS OFFSHORE
WITHIN THE ANTI-CYCLONIC BRANCH OF THE WARM CONVEYOR BELT WHERE HIGH
THETA-E VALUES RESIDE BENEATH DIFFLUENCE AND ENHANCED ASCENT WITH
CONVERGENCE ALONG A STRONG H925-7 JET. S NEW ENGLAND BELOW THE RIGHT-
FRONT-QUADRANT OF THE UPPER-LEVEL-JET AND IN THE CROSS-HAIRS OF A
MID-LEVEL DRY-PUNCH WRAPPING INTO THE OCCLUDING SYSTEM PER ENSEMBLE
MEANS LOOKS TO RESULT IN LITTLE OUTCOME OVER THE AREA. IN OTHER
WORDS...NOT APPEARING TO BE A WASHOUT ON SUNDAY. CAN NOT RULE OUT
HIGHER AMOUNTS OVER THE HIGHER TERRAIN.
WITH ENSEMBLES LIFTING THE TROWAL N OF THE REGION SUNDAY NIGHT INTO
MONDAY...LESS CONFIDENCE OF OUTCOMES ON MONDAY BENEATH THE COLD POOL
AS THE TROUGH MAY MOVE THRU PRIOR TO BOUNDARY-LAYER DESTABILIZATION.
PERHAPS SOME ACTIVITY UP AGAINST THE W-SLOPES OF HIGHER TERRAIN N OF
OUR AREA WITH W-WIND CONVERGENCE.
FOR THE REMAINDER OF THE WEEK...CONSISTENT SIGNALS OF RIDGING. THINK
HEAT AND HUMIDITY BUILD BACK INTO THE REGION. AGREE WITH THE CLIMATE
PREDICTION CENTER WITH ABOVE-AVERAGE TEMPERATURES. ENSEMBLES SIGNAL
ANOMALOUS H85 TEMPERATURES ACROSS THE REGION. THINKING THAT WE COULD
BREAK SOME RECORD HIGH TEMPERATURES INTO MID- TO LATE-SEPTEMBER.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...
TONIGHT...MODERATE CONFIDENCE. IFR AND SOME LIFR CIGS/VSBYS IN
SHOWERS/TSTMS WITH HEAVY DOWNPOURS. NORTHEAST SURFACE WINDS INTO
NORTHERN MASS AND PARTS OF CT WHILE SOUTHEAST MASS/RI MAY TURN TO
SOUTH WINDS FOR A TIME DURING THE NIGHT. ALL AREAS TURN TO NORTH
BY FRIDAY MORNING.
FRIDAY...MODERATE CONFIDENCE.
IMPROVING CONDITIONS FRIDAY MORNING AS THE WEATHER SYSTEM MOVES
OFF TO THE EAST. EXPECT MVFR/IFR CONDITIONS IMPROVING TO VFR
BETWEEN SUNRISE AND MIDDAY. CLEARING TREND IN THE CT VALLEY DURING
THE AFTERNOON. NORTHEAST WINDS GUSTING TO 20 KNOTS ALONG THE EAST
COAST.
FRIDAY NIGHT...HIGH CONFIDENCE.
VFR ALL AREAS. AREAS OF IFR/LIFR IN FOG DEVELOPING AFTER MIDNIGHT
ESPECIALLY IN THE CT VALLEY.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY...HIGH CONFIDENCE.
VFR. WINDS VEERING E/SE. A MAINLY DRY FORECAST.
SATURDAY NIGHT - SUNDAY NIGHT...MODERATE CONFIDENCE.
MVFR-IFR MIX WITH E/SE-ONSHORE FLOW BACKING SW TOWARDS THE END OF
THE FORECAST PERIOD. RAIN LIKELY ACROSS THE REGION. PATCHY FOG
POSSIBLE. MAY ALSO CONTEND WITH SOME LLWS IMPACTS.
MONDAY INTO TUESDAY...MODERATE CONFIDENCE.
VFR. W/SW-WINDS WITH GUSTS UP TO 20 KTS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE IN TRENDS.
MODERATE CONFIDENCE IN SPECIFIC TIMING.
TONIGHT...INCREASING COVERAGE IN SHOWERS AND THUNDERSTORMS.
LOCALLY HEAVY DOWNPOURS POSSIBLE. AREAS OF POOR VISIBILITY IN FOG
ESPECIALLY AROUND NANTUCKET
FRIDAY...LOW PRESSURE LIFTING NE ACROSS THE WATERS. SHOWERS AND
AREAS OF FOG START THE DAY. INCREASING NORTH WINDS WILL REACH 20
KNOTS ON OUR EASTERN WATERS AND COULD GET AS STRONG AS 25 KT. THE
N-NE FETCH SHOULD BE ENOUGH TO BUILD SEAS ON THE EXPOSED EASTERN
WATERS TO 5 FEET...POSSIBLY 6. A SMALL CRAFT ADVISORY HAS BEEN
POSTED ON THE OUTER WATERS AND IN MASS BAY...PRIMARILY FOR SEAS
BUT WITH AN EYE TOWARD THE WINDS AS WELL.
FRIDAY NIGHT...MODERATE CONFIDENCE.
DIMINISHING NORTH TO NORTHWEST WINDS WITH SEAS SUBSIDING AFTER
MIDNIGHT.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY...MODERATE CONFIDENCE.
A LULL IN THE WEATHER. WINDS BECOME LIGHT WHILE VEERING E/SE. SHOULD
SEE SEAS SUBSIDE FOR THE PERIOD BELOW 5-FEET.
SUNDAY...MODERATE CONFIDENCE.
DEEPER AREA OF LOW PRESSURE TO THE W. WILL SEE AN ACCOMPANYING WARM
FRONT LIFT N ACROSS THE WATERS BRINGING WITH IT RAIN ALONG WITH
INCREASING E/SE-ONSHORE WINDS. GUSTS UP TO 20 KTS. WAVE HEIGHTS
BUILDING IN EXCESS OF 5-FEET INITIALLY OVER THE S WATERS EXPANDING
TO THE E/SE WATERS LATE IN THE PERIOD.
MONDAY...MODERATE CONFIDENCE.
IMPROVING. WINDS BACK OUT OF THE W/SW AND REMAIN ROBUST WITH A
STRONG AREA OF LOW PRESSURE SITUATED WELL TO THE W ACROSS THE
INTERIOR. ANOTHER DAY OF GUSTS UP TO 20 KTS WHILE SEAS REMAIN AT OR
IN EXCESS OF 5-FEET ON THE WATERS.
&&
.HYDROLOGY...
GUIDANCE SHOWS RAINFALL AMOUNTS OF UP TO 3 INCHES TONIGHT AND
EARLY FRIDAY. KBOX RADAR HAS ESTIMATED RAINFALL RATES OF 2-4
INCHES/HOUR WITH SOME OF THE SHOWERS TODAY.
MODELS AGREE ON LIFTING THE FRONT NORTH TONIGHT...USING A PIVOT
POINT NEAR NEW YORK CITY...BUT WITH DIFFERENCES ON HOW FAR NORTH.
THE HRRR CARRIES THE FRONT TO THE WORCESTER HILLS. THE GFS BRINGS
THE 925 MB FRONT UP TO NRN RI AND THE SOUTHERN BORDER OF NORFOLK
COUNTY BY 11 PM. WITH DIFFERENCES LIKE THIS...IT IS DIFFICULT TO
FINE-TUNE THE MOST PRONE AREAS FOR HIGH PCPN.
WE HAVE ISSUED A FLASH FLOOD WATCH THAT WILL GO ALONG WITH THE
EARLIER-ISSUED WATCH. BETWEEN THE TWO WATCHES...ALL OF OUR AREA IS
COVERED EXCEPT FOR THE ISLANDS. THE EARLIER WATCH EXPIRES AT
MIDNIGHT...BUT MAY BE EXTENDED. THE LATER WATCH CONTINUES
THROUGH THE NIGHT. BASED ON THE HIGH RAINFALL RATES...ANY FLOODING
THAT DOES DEVELOP SHOULD DO SO QUICKLY.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR CTZ002>004.
MA...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR MAZ017>022.
FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR MAZ002>016-026.
RI...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR RIZ002>007.
FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR RIZ001.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM FRIDAY TO 6 AM EDT SATURDAY FOR
ANZ250-254.
SMALL CRAFT ADVISORY FROM 5 AM TO 4 PM EDT FRIDAY FOR ANZ251.
SMALL CRAFT ADVISORY FROM 2 PM FRIDAY TO 2 AM EDT SATURDAY FOR
ANZ255-256.
&&
$$
SYNOPSIS...WTB/EVT
NEAR TERM...WTB
SHORT TERM...WTB
LONG TERM...EVT
AVIATION...WTB/EVT
MARINE...WTB/EVT
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
352 PM EDT THU SEP 10 2015
.SYNOPSIS...
A FRONT STALLED ALONG THE SOUTHERN NEW ENGLAND SOUTH COAST WILL
PUSH NORTH OVERNIGHT AND PROVIDE A FOCUS FOR LOCALLY HEAVY
DOWNPOURS DURING THE NIGHT. LOW PRESSURE FROM THE MID ATLANTIC
STATES WILL MOVE NORTHEAST PAST OUR AREA FRIDAY MORNING. WEAK
HIGH PRESSURE THEN BRINGS A LULL IN THE WEATHER SATURDAY. WET-
WEATHER RETURNS FOR SUNDAY BUT NOT APPEARING TO BE A WASHOUT.
PERHAPS SOME HEAVY RAIN FOR THE HIGH TERRAIN AND SOUTHEAST NEW
ENGLAND. TURNING DRY AND WARMER INTO NEXT WEEK. COULD BE LOOKING
AT THE POSSIBILITY OF RECORD BREAKING HEAT INTO MID- TO LATE-
SEPTEMBER AS ABOVE-AVERAGE TEMPS ARE FORECAST.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A COLD FRONT LIES NORTH OF NANTUCKET BUT SOUTH OF THE REMAINDER OF
NEW ENGLAND AND LONG ISLAND. SOUTHWEST FLOW ALOFT HAS A FAINT
SHORTWAVE MOVING THROUGH WITH LOW LEVEL FLOW DRAWING VERY MOST AIR
NORTH OVER THE TOP OF THE FRONT. PRECIPITABLE WATER VALUES
CONTINUE EITHER SIDE OF 2 INCHES...WHICH IS ABOUT AS HIGH AS IT
GETS IN SOUTHERN NEW ENGLAND IN SEPTEMBER.
THE SURFACE FRONT SUPPORTS LOW LEVEL CONVERGENCE AND THE UPPER
SHORTWAVE SUPPORTS UPPER VENTING...AND THIS WILL BE WORKING ON A
VERY JUICY AIRMASS. WE WILL CONTINUE WITH CATEGORICAL POPS FOR
SHOWERS/SCATTERED TSTMS THIS EVENING AND TONIGHT. BASED ON THE
HIGH PW AIR...WE CONTINUE TO EXPECT LOCALLY HEAVY DOWNPOURS THAT
WILL BRING LOCALLY HEAVY DOWNPOURS. BEST CHANCE WILL BE WITH THE
BEST LIFT ALONG AND NORTH OF THE FRONT.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
COASTAL LOW PRESSURE MOVES OFF TO THE EAST FRIDAY
MORNING...CARRYING ANY REMAINING PCPN OFF TO THE EAST. MODEL
MOISTURE FIELDS SHOW DRYING FROM WEST TO EAST DURING THE
DAY...SUGGESTING A CLEARING TREND FRIDAY AFTERNOON INTO FRIDAY
NIGHT.
MEANWHILE...A LARGER UPPER SHORTWAVE DIGS OVER THE GREAT LAKES AND
MAINTAINS A SOUTHWEST FLOW ALOFT. THE SUPPORTING UPPER JET WILL BE
POSITIONED OVER THE EASTERN GREAT LAKES...GENERATING MORE CONVECTION
IN THAT AREA WHILE NEW ENGLAND HAS WEAK SUBSIDENCE. SO FRIDAY
AFTERNOON AND NIGHT SHOULD BE A DRY PERIOD. NORTH WIND FRIDAY WILL
DIMINISH FRIDAY NIGHT INLAND.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
*/ HIGHLIGHTS...
- KEEPING IT DRY ON SATURDAY
- WET WEATHER FOR SUNDAY BUT NOT LOOKING LIKE A WASHOUT EVERYWHERE
- HEAVY RAIN THOUGH MAY IMPACT SE NEW ENGLAND ... HIGH TERRAIN
- DRY AND WARM INTO NEXT WEEK ... POSSIBLE RECORD BREAKING HEAT
*/ DISCUSSION...
KEEPING WITH AN ENSEMBLE APPROACH. H5 DEEP-TROUGH CLOSED LOW SWEEPS
THROUGH THE OHIO-RIVER VALLEY SATURDAY AHEAD OF WHICH THERE IS RIDGE-
AMPLIFICATION KEEPING US MOSTLY DRY WITH LIKELY SOME MID-HIGH LEVEL
CLOUDS ACROSS THE REGION. LIFTING E SUNDAY DIFFLUENCE PROCEEDS ABOVE
LOW-MID LEVEL LIFT / CONVERGENCE BUT CONVINCED S NEW ENGLAND IS IN
AN AREA OF LESS FAVORABLE DEVELOPMENT. TWO AREAS OF INTEREST: THE
CYCLONIC TROWALING ROUND THE CLOSED LOW BACK INTO THE E GREAT LAKES
WHERE DEFORMATION PROCEEDS...AND SE NEW ENGLAND AND POINTS OFFSHORE
WITHIN THE ANTI-CYCLONIC BRANCH OF THE WARM CONVEYOR BELT WHERE HIGH
THETA-E VALUES RESIDE BENEATH DIFFLUENCE AND ENHANCED ASCENT WITH
CONVERGENCE ALONG A STRONG H925-7 JET. S NEW ENGLAND BELOW THE RIGHT-
FRONT-QUADRANT OF THE UPPER-LEVEL-JET AND IN THE CROSS-HAIRS OF A
MID-LEVEL DRY-PUNCH WRAPPING INTO THE OCCLUDING SYSTEM PER ENSEMBLE
MEANS LOOKS TO RESULT IN LITTLE OUTCOME OVER THE AREA. IN OTHER
WORDS...NOT APPEARING TO BE A WASHOUT ON SUNDAY. CAN NOT RULE OUT
HIGHER AMOUNTS OVER THE HIGHER TERRAIN.
WITH ENSEMBLES LIFTING THE TROWAL N OF THE REGION SUNDAY NIGHT INTO
MONDAY...LESS CONFIDENCE OF OUTCOMES ON MONDAY BENEATH THE COLD POOL
AS THE TROUGH MAY MOVE THRU PRIOR TO BOUNDARY-LAYER DESTABILIZATION.
PERHAPS SOME ACTIVITY UP AGAINST THE W-SLOPES OF HIGHER TERRAIN N OF
OUR AREA WITH W-WIND CONVERGENCE.
FOR THE REMAINDER OF THE WEEK...CONSISTENT SIGNALS OF RIDGING. THINK
HEAT AND HUMIDITY BUILD BACK INTO THE REGION. AGREE WITH THE CLIMATE
PREDICTION CENTER WITH ABOVE-AVERAGE TEMPERATURES. ENSEMBLES SIGNAL
ANOMALOUS H85 TEMPERATURES ACROSS THE REGION. THINKING THAT WE COULD
BREAK SOME RECORD HIGH TEMPERATURES INTO MID- TO LATE-SEPTEMBER.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...
TONIGHT...MODERATE CONFIDENCE. IFR AND SOME LIFR CIGS/VSBYS IN
SHOWERS/TSTMS WITH HEAVY DOWNPOURS. NORTHEAST SURFACE WINDS INTO
NORTHERN MASS AND PARTS OF CT WHILE SOUTHEAST MASS/RI MAY TURN TO
SOUTH WINDS FOR A TIME DURING THE NIGHT. ALL AREAS TURN TO NORTH
BY FRIDAY MORNING.
FRIDAY...MODERATE CONFIDENCE.
IMPROVING CONDITIONS FRIDAY MORNING AS THE WEATHER SYSTEM MOVES
OFF TO THE EAST. EXPECT MVFR/IFR CONDITIONS IMPROVING TO VFR
BETWEEN SUNRISE AND MIDDAY. CLEARING TREND IN THE CT VALLEY DURING
THE AFTERNOON. NORTHEAST WINDS GUSTING TO 20 KNOTS ALONG THE EAST
COAST.
FRIDAY NIGHT...HIGH CONFIDENCE.
VFR ALL AREAS. AREAS OF IFR/LIFR IN FOG DEVELOPING AFTER MIDNIGHT
ESPECIALLY IN THE CT VALLEY.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY...HIGH CONFIDENCE.
VFR. WINDS VEERING E/SE. A MAINLY DRY FORECAST.
SATURDAY NIGHT - SUNDAY NIGHT...MODERATE CONFIDENCE.
MVFR-IFR MIX WITH E/SE-ONSHORE FLOW BACKING SW TOWARDS THE END OF
THE FORECAST PERIOD. RAIN LIKELY ACROSS THE REGION. PATCHY FOG
POSSIBLE. MAY ALSO CONTEND WITH SOME LLWS IMPACTS.
MONDAY INTO TUESDAY...MODERATE CONFIDENCE.
VFR. W/SW-WINDS WITH GUSTS UP TO 20 KTS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE IN TRENDS.
MODERATE CONFIDENCE IN SPECIFIC TIMING.
TONIGHT...INCREASING COVERAGE IN SHOWERS AND THUNDERSTORMS.
LOCALLY HEAVY DOWNPOURS POSSIBLE. AREAS OF POOR VISIBILITY IN FOG
ESPECIALLY AROUND NANTUCKET
FRIDAY...LOW PRESSURE LIFTING NE ACROSS THE WATERS. SHOWERS AND
AREAS OF FOG START THE DAY. INCREASING NORTH WINDS WILL REACH 20
KNOTS ON OUR EASTERN WATERS AND COULD GET AS STRONG AS 25 KT. THE
N-NE FETCH SHOULD BE ENOUGH TO BUILD SEAS ON THE EXPOSED EASTERN
WATERS TO 5 FEET...POSSIBLY 6. A SMALL CRAFT ADVISORY HAS BEEN
POSTED ON THE OUTER WATERS AND IN MASS BAY...PRIMARILY FOR SEAS
BUT WITH AN EYE TOWARD THE WINDS AS WELL.
FRIDAY NIGHT...MODERATE CONFIDENCE.
DIMINISHING NORTH TO NORTHWEST WINDS WITH SEAS SUBSIDING AFTER
MIDNIGHT.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY...MODERATE CONFIDENCE.
A LULL IN THE WEATHER. WINDS BECOME LIGHT WHILE VEERING E/SE. SHOULD
SEE SEAS SUBSIDE FOR THE PERIOD BELOW 5-FEET.
SUNDAY...MODERATE CONFIDENCE.
DEEPER AREA OF LOW PRESSURE TO THE W. WILL SEE AN ACCOMPANYING WARM
FRONT LIFT N ACROSS THE WATERS BRINGING WITH IT RAIN ALONG WITH
INCREASING E/SE-ONSHORE WINDS. GUSTS UP TO 20 KTS. WAVE HEIGHTS
BUILDING IN EXCESS OF 5-FEET INITIALLY OVER THE S WATERS EXPANDING
TO THE E/SE WATERS LATE IN THE PERIOD.
MONDAY...MODERATE CONFIDENCE.
IMPROVING. WINDS BACK OUT OF THE W/SW AND REMAIN ROBUST WITH A
STRONG AREA OF LOW PRESSURE SITUATED WELL TO THE W ACROSS THE
INTERIOR. ANOTHER DAY OF GUSTS UP TO 20 KTS WHILE SEAS REMAIN AT OR
IN EXCESS OF 5-FEET ON THE WATERS.&&
.HYDROLOGY...
GUIDANCE SHOWS RAINFALL AMOUNTS OF UP TO 3 INCHES TONIGHT AND
EARLY FRIDAY. KBOX RADAR HAS ESTIMATED RAINFALL RATES OF 2-4
INCHES/HOUR WITH SOME OF THE SHOWERS TODAY.
MODELS AGREE ON LIFTING THE FRONT NORTH TONIGHT...USING A PIVOT
POINT NEAR NEW YORK CITY...BUT WITH DIFFERENCES ON HOW FAR NORTH.
THE HRRR CARRIES THE FRONT TO THE WORCESTER HILLS. THE GFS BRINGS
THE 925 MB FRONT UP TO NRN RI AND THE SOUTHERN BORDER OF NORFOLK
COUNTY BY 11 PM. WITH DIFFERENCES LIKE THIS...IT IS DIFFICULT TO
FINE-TUNE THE MOST PRONE AREAS FOR HIGH PCPN.
WE HAVE ISSUED A FLASH FLOOD WATCH THAT WILL GO ALONG WITH THE
EARLIER-ISSUED WATCH. BETWEEN THE TWO WATCHES...ALL OF OUR AREA IS
COVERED EXCEPT FOR THE ISLANDS. THE EARLIER WATCH EXPIRES AT
MIDNIGHT...BUT MAY BE EXTENDED. THE LATER WATCH CONTINUES
THROUGH THE NIGHT. BASED ON THE HIGH RAINFALL RATES...ANY FLOODING
SHOULD DEVELOP QUICKLY.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR CTZ002>004.
MA...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR MAZ017>022.
FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR MAZ002>016-026.
RI...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR RIZ002>007.
FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR RIZ001.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM FRIDAY TO 6 AM EDT SATURDAY FOR
ANZ250-254.
SMALL CRAFT ADVISORY FROM 5 AM TO 4 PM EDT FRIDAY FOR ANZ251.
SMALL CRAFT ADVISORY FROM 2 PM FRIDAY TO 2 AM EDT SATURDAY FOR
ANZ255-256.
&&
$$
SYNOPSIS...WTB/BDS
NEAR TERM...WTB
SHORT TERM...WTB
LONG TERM...BDS
AVIATION...WTB/BDS
MARINE...WTB/BDS
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
356 PM EDT THU SEP 10 2015
.SYNOPSIS...
19Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A BROAD BUT AMPLIFIED
UPPER LEVEL PATTERN IN PLACE OVER THE CONUS LATE THIS AFTERNOON.
PATTERN CONSISTS OF RIDGING OVER THE PACIFIC COAST/INTER-MOUNTAIN
WEST...FOLLOWED DOWNSTREAM BY LONGWAVE TROUGHING FROM THE CENTRAL
PLAINS TO THE EASTERN SEABOARD. VERY GOOD CONSENSUS AMONG THE
GUIDANCE MEMBERS THAT THIS EASTERN CONUS TROUGH WILL UNDERGO MORE
SIGNIFICANT AMPLIFICATION DURING THE NEXT 24-30 HOURS...AS A A
SERIES OF STRONG SHORTWAVE IMPULSES CURRENTLY OVER THE UPPER MS
VALLEY AND SOUTHERN CANADA DROP QUICKLY INTO THE LONGWAVE
CYCLONIC FLOW. THIS STRONG AMPLIFICATION TO THE PATTERN WILL
IMPACT OUR LOCAL WEATHER BY SATURDAY WHEN ONE OF THE DEEPEST
SOUTHWARD PENETRATIONS OF A FRONTAL SYSTEM SEEN IN SEVERAL MONTHS
TAKES PLACE. NO...THIS FRONT IS NOT EXPECTED TO BRING US ANY
SIGNIFICANT RELIEF FROM THE SUMMER HEAT AND HUMIDITY AS IT QUICKLY
DECAYS ONCE REACHING NORTHERN FLORIDA. HOWEVER...IT IS LIKELY TO
BRING WIDESPREAD SHOWER ACTIVITY TO THE REGION FOR THE FIRST HALF
OF THE WEEKEND...AND IS A FIRST SIGN FOR THIS PART OF THE COUNTRY
THAT THE SEASONS ARE JUST NOW BEGINNING TO CHANGE.
CURRENTLY AHEAD OF ALL THIS...WE FIND OUR FORECAST AREA UNDER A
LARGE DOME OF MID/UPPER LEVEL RIDGING THAT EXTENDS SOUTHWARD AND
EASTWARD TO CUBA AND THE BAHAMA ISLANDS. THE LOWER LEVELS ARE
DOMINATED BY THE SUBTROPICAL RIDGE AXIS THAT EXTENDS ACROSS THE
CENTRAL/SOUTHERN FL PENINSULA AND EASTERN GULF OF MEXICO. BOTH OF
THESE FEATURES WILL BE WEAKENING AND PUSHING SOUTHWARD IN THE NEXT
24 HOURS IN RESPONSE TO THE AMPLIFYING TROUGH TO OUR NORTH.
REGIONAL RADARS AS OF 4PM EDT DO SHOW A FEW SCATTERED
STORMS...MAINLY SOUTH OF THE TAMPA BAY AREA AND ALONG/EAST OF THE
I-75 CORRIDOR. ALTHOUGH AN ISOLATED STORM IS POSSIBLE FOR ANYONE
THE NEXT FEW HOURS...THE BEST CHANCES INTO THE EARLY EVENING WILL
BE THE SOUTH-CENTRAL INTERIOR ZONES TO THE EAST OF THE I-75
CORRIDOR AS THE SEA-BREEZE MAKES STEADY PROGRESS INLAND FROM THE
COAST.
&&
.SHORT TERM (TONIGHT AND FRIDAY)...
UPPER TROUGH BEGINS TO DEAMPLIFY ON THE NORTHERN SIDE BY EARLY
FRIDAY AMID HEIGHT FALLS OVER THE NORTH-CENTRAL GULF COAST AND A
SIGNIFICANT VORTICITY CENTER/HEIGHT FALLS REGION WORKING DOWN
INTO THE MIDDLE MS VALLEY. THE SUBTROPICAL RIDGE AXIS WILL HAVE
SETTLED TO SOUTH FLORIDA AND THE FL STRAITS BY SUNRISE AND THEN
HOLD IN PLACE THROUGH THE DAY ON FRIDAY.
AFTER A FEW EVENING STORMS DISSIPATED WITH SUNSET...THE MAJORITY
OF THE OVERNIGHT LOOKS QUIET AND DRY WITH SEASONABLE TEMPERATURES.
LATE TONIGHT...THE COMBINATION OF SOME WEAK SYNOPTIC SUPPORT ALOFT
FROM THE INCREASING DEEP LAYER CYCLONIC FLOW...SLIGHTLY MORE
FAVORABLE LOW/MID LEVEL LAPSE RATES...AND CLIMO PREFERRED
SOUTHWEST FLOW SHOULD RESULT IN A SCATTERING OF SHOWERS/STORMS
BREAKING OUT OVER THE NORTHEAST GULF OF MEXICO. MAY SEE AN
ISOLATED STORM COME ASHORE AFTER 11-12Z AS FAR SOUTH AS CHARLOTTE
HARBOR...HOWEVER THE BEST COVERAGE AND OVERALL SHOWER POTENTIAL
LOOKS TO BE NORTH OF TAMPA BAY...AND ESPECIALLY UP TOWARD
CITRUS/LEVY COUNTIES.
SIMILAR TO WHAT OCCURRED TODAY...AS THE DAY PROGRESSES...THE
BETTER CHANCES FOR DEVELOPING STORMS WILL SHIFT FROM THE NATURE
COAST TO AREAS JUST INLAND FROM THE SUNCOAST BEACHES. THESE AREAS
SOUTH OF TAMPA BAY WILL SEE THE BEST FOCUS ALONG THE SEA-BREEZE
AND ALSO THE BETTER POTENTIAL FOR SUBSTANTIAL INSOLATION/HEATING.
NORTH OF TAMPA...AFTER THE NOCTURNAL CONVECTION FADES...MORE
ABUNDANT CLOUDS AND A SYNOPTIC FLOW AIDING SEA-BREEZE PROPAGATION
SHOULD TREND TOWARD LESS SHOWER COVERAGE DURING THE AFTERNOON
HOURS.
THE MOST NUMEROUS SHOWER ACTIVITY IN THE FORECAST PERIOD LOOKS TO
ARRIVE ACROSS THE REGION ON SATURDAY...MAKING THE FIRST HALF OF
THE UPCOMING WEEKEND LESS THAN IDEAL FOR OUTDOOR ACTIVITIES. MORE
ON THIS SETUP AND POTENTIAL IN THE LONG TERM DISCUSSION BELOW.
&&
.MID/LONG TERM (FRIDAY NIGHT - THURSDAY...A HIGHLY AMPLIFIED PATTERN
IN THE MID/UPPER LEVELS IS SETTING UP OVER THE EASTERN HALF OF THE
CONUS. A DEEPENING TROUGH EXTENDS SOUTH FROM A CLOSED LOW OVER THE
ONTARIO/QUEBEC BORDER THROUGH THE MISSISSIPPI RIVER VALLEY AND INTO
THE NORTHERN GULF OF MEXICO. THIS TROUGH MOVES EAST BY SUNDAY AND
FURTHER DEEPENS SOUTHWARD OVER THE FLORIDA PANHANDLE. BY EARLY
MONDAY MORNING...THE TROUGH LIFTS NORTHEAST AND ANOTHER CLOSED
MID/UPPER LEVEL LOW DEVELOPS OVER PENNSYLVANIA. THIS LOW CONTINUES
MOVING NORTHEAST AND RAPIDLY DEEPENS OFF THE NEW ENGLAND COAST BY
TUESDAY NEXT WEEK. AS THE UPPER LOW MOVES NORTHEAST...HIGH PRESSURE
RIDGING BUILDS INTO THE SOUTHEAST CONUS. BY LATE TUESDAY...AN UPPER
LEVEL HIGH SETS UP OVER THE FLORIDA PENINSULA AND WILL BUILD FARTHER
WESTWARD INTO THE GULF OF MEXICO THROUGH THE REMAINDER OF NEXT WEEK.
ON THE SURFACE...THE SUBTROPICAL HIGH RIDGE EAST OF FLORIDA BREAKS
DOWN AS A FRONTAL BOUNDARY EXTENDS SOUTHWEST FROM A LOW PRESSURE
CENTER OFF THE NEW ENGLAND COAST. THIS FRONT WILL SINK SOUTH OVER
NORTHERN FLORIDA AND ALONG THE NORTHERN GULF COAST. MODELS ARE IN
GOOD AGREEMENT WITH KEEPING THIS COLD FRONT PRIMARILY OVER THE
NORTHERN HALF OF FLORIDA BETWEEN THE I-10 CORRIDOR AND TAMPA BAY
THROUGH LATE SUNDAY. WEST SOUTHWEST ONSHORE FLOW AND SCATTERED TO
NUMEROUS SHOWERS AND STORMS ASSOCIATED WITH THIS FRONT WILL CONTINUE
THROUGH THE WEEKEND. THESE STORMS HAVE THE POTENTIAL FOR PRODUCING
GUSTY WINDS AND HEAVY DOWNPOURS. CONDITIONS WILL IMPROVE ON MONDAY
AS THE FRONT BEGINS TO DISSIPATE AS HIGH PRESSURE MOVES IN FROM THE
NORTH OVER TENNESSEE. DRIER CONDITIONS AND EAST SOUTHEAST WINDS WILL
RETURN TO THE FLORIDA PENINSULA. THIS WILL ALLOW FOR A MORE TYPICAL
SEA BREEZE WEATHER PATTERN TO SETUP WITH ISOLATED TO SCATTERED
AFTERNOON STORMS POSSIBLE NEXT WEEK. TEMPERATURES WILL BE A FEW
DEGREES COOLER ON SATURDAY AND SUNDAY DUE TO EXTENSIVE CLOUDINESS
AND RAINFALL...THEN WARMING BACK UP TO NORMAL NEXT WEEK.
&&
.AVIATION...
VFR CONDITIONS PREVAIL ACROSS WEST-CENTRAL AND SOUTHWEST FLORIDA
THIS AFTERNOON. SCT STORMS LIE BETWEEN KSRQ AND KFMY WITH ANY
TERMINALS BETWEEN THESE SPOTS POSSIBLY SEEING A BRIEF DOWNPOUR
THROUGH 21Z. MUCH OF THE EVENING AND OVERNIGHT WILL SEE VFR
CONDITIONS CONTINUE UNDER A SCT-BKN HIGH LEVEL CLOUD DECK. A FEW
SHOWERS WILL BE POSSIBLE FRIDAY MORNING MOVING ASHORE FROM THE
GULF...ESPECIALLY FOR KTPA/KPIE/KSRQ...HOWEVER NO SIGNIFICANT OR
EXTENDED RESTRICTIONS ARE ANTICIPATED WITH THIS ACTIVITY.
&&
.MARINE...
HIGH PRESSURE OVER THE EASTERN GULF OF MEXICO WILL PERSIST THROUGH
FRIDAY BEFORE WEAKENING AND DROPPING SOUTHWARD IN RESPONSE TO THE
APPROACH OF A FRONTAL SYSTEM FROM THE NORTH. THIS COLD FRONT IS
EXPECTED TO ARRIVE OVER THE NORTHERN GULF LATE SATURDAY AND THEN
QUICKLY WEAKEN AS IT DROPS SOUTH INTO THE DAY ON SUNDAY. HIGH
PRESSURE THEN BUILDS NORTH OF THE FORECAST WATERS BY THE EARLY
PORTION OF NEXT WEEK. A BRIEF PERIOD OF NEAR CAUTIONARY WINDS WILL
BE POSSIBLE SATURDAY NIGHT OR EARLY SUNDAY TO THE NORTH OF TAMPA
BAY...BUT OTHERWISE WINDS AND SEAS WILL REMAIN BELOW HEADLINE
CRITERIA THROUGH THE PERIOD. SCATTERED SHOWERS AND STORMS ARE
LIKELY TO BECOME MORE NUMEROUS ON SATURDAY AHEAD OF THE ADVANCING
FRONT. LOCALLY STRONGER WINDS AND ROUGH SEAS WILL BE POSSIBLE WITH
THUNDERSTORMS.
&&
.FIRE WEATHER...
SURFACE HIGH PRESSURE OVER THE STATE WILL PERSIST THROUGH THE DAY
ON FRIDAY...AND THEN BEGIN TO SETTLE SOUTHWARD AND WEAKEN IN
RESPONSE TO THE APPROACH OF A COLD FRONT FROM THE NORTH. THIS
FRONT WILL ENTER THE NORTHERN PART OF THE STATE LATE SATURDAY...
AND THEN WEAKEN QUICKLY AS IT SETTLES SOUTHWARD INTO SUNDAY. AT
THIS TIME NO SIGNIFICANT CHANGE TO A DRIER AIRMASS IS EXPECTED
WITH THIS FRONT...AND IN FACT...SOME AREAS OF LOCALLY HEAVIER
RAINFALL WILL BE POSSIBLE SATURDAY AHEAD OF THE FRONT FOR
SATURDAY. RELATIVE HUMIDITY VALUES WILL REMAIN WELL ABOVE
LEVELS THROUGH THE PERIOD.
FOG POTENTIAL...PATCHY LIGHT GROUND FOG WILL BE POSSIBLE EACH
MORNING THROUGH THE WEEKEND...HOWEVER NO SIGNIFICANT AREAS OF FOG
ARE ANTICIPATED.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 79 90 78 87 / 10 20 40 80
FMY 78 92 77 90 / 10 30 20 60
GIF 76 91 75 88 / 10 50 40 80
SRQ 78 89 77 88 / 10 30 50 80
BKV 74 90 74 87 / 10 20 40 80
SPG 80 89 78 86 / 10 20 50 80
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WX...MROCZKA
LONG TERM/DECISION SUPPORT...WYNN
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1240 PM CDT THU SEP 10 2015
.UPDATE...
ISSUED AT 1004 AM CDT THU SEP 10 2015
Outflow boundary from convection in northern Illinois showing up
nicely on regional radar mosaics, located just north of I-80 at 10
am. This may slip into the far northern CWA over the next couple
hours, although latest HRRR does not show much further south
progress. However, the actual cold front will be advancing into
southeast Iowa through midday, and the combination of this and the
remnants of the outflow will start to trigger additional shower
and thunderstorm development. PoP`s have been adjusted a bit to
time the higher chances of rain, largely keeping the rest of the
morning dry.
Little change needed to overall high temperatures, but have made
some adjustments to the hourly trends. Arrival of convection will
likely result in some falling temperatures over the far northwest
later this afternoon.
&&
.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT THU SEP 10 2015
Narrow ridge over the area is keeping clear skies across the central
and southeast parts of the CWA early this morning. Where high clouds
were last to clear last night, dense fog has developed; which is
mainly in southeast IL. Considering a dense fog advisory for about 5-
6 hours this morning. Will make last minute decision on this.
Believe this fog will likely last for a couple of hours this
morning. As the ridge moves east a frontal system will move in from
the northwest and bring the chance of showers and isolated
thunderstorms to areas northwest of a Jacksonville to Pontiac line,
mainly during the afternoon.
Cooler temps are expected today as cooler air advects into the area,
so below normal temps will occur across the whole CWA. Light winds
will become more westerly this afternoon, with wind speeds less than
10kts.
.LONG TERM...(TONIGHT THROUGH Wednesday)
ISSUED AT 330 AM CDT THU SEP 10 2015
Cold front exits southeast IL tonight with much cooler air ushering
into the region on increasing NW breezes especially by Friday
morning. A strong upper level trof digs into the area by 12Z/Fri and
will spread a good chance of showers from NW to SE across area
tonight, with southeast IL likely staying dry through this evening.
Instability parameters look weak for thunder and only carried
isolated thunder to central IL this evening and into southeast IL
overnight. Lows overnight in the upper 50s/lower 60s except near 55F
by Galesburg. Cooler highs Friday range from upper 60s NW of IL
river to mid 70s southeast of I-70 as mostly cloudy skies prevail
Friday. Chances of rain showers Friday will be mainly east of the IL
river with highest pops of 40-50% in eastern/SE IL.
Forecast models have trended stronger with upper level trof and
embedded cutoff upper level low over eastern/SE IL by Saturday
afternoon and gives isolated light rain showers in eastern IL from I-
57 east where more clouds expected. Cool highs in the mid to upper
60s on Saturday. Lows Friday night in the upper 40s/lower 50s and
then mid to upper 40s for lows Sat night.
Stronger upper level trof begins to pull east of IL across the ohio
river valley on Sunday with more sunshine expected and temps
moderating a bit with highs around 70F. Lows Sunday night mostly in
the lower 50s with eastern IL around 50F.
00Z medium and extended forecast models continue to show upper level
trof pulling away from IL during Mon-Wed time frame as upper level
ridge builds into the area and provides a stretch of dry weather.
Below normal temperatures early next week with highs Monday 75-
80F will climb to a bit above normal by Wed with highs in the 80s.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Friday Afternoon)
ISSUED AT 1240 PM CDT THU SEP 10 2015
Outflow boundary from convection in northern Illinois is
approaching KPIA/KBMI from the north. While the ongoing convection
is expected to remain north of these TAF sites, high-res models
develop scattered convection along this boundary as it drops into
central Illinois. Already starting to see some development along
the IL/IA border west of KGBG ahead of the boundary. Have made
some adjustments to the timing of the VCTS, speeding it up by a
couple hours in most cases. The main cold front remains further
northwest and will likely start affecting central Illinois toward
06Z. After tailing off for a time, some increase in showers is
possible late tonight, but currently think the overnight thunder
potential will remain further south. Northerly winds may become
gusty toward the end of the forecast period, with cold air
advection taking place.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Auten
LONG TERM...07
AVIATION...Geelhart
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
430 PM EDT THU SEP 10 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 350 PM EDT THU SEP 10 2015
CHANCES FOR RAIN WILL INCREASE LATE TONIGHT THROUGH FRIDAY AS A COLD
FRONT MOVES THROUGH THE AREA. MUCH COOLER FALL-LIKE WEATHER WILL
FOLLOW FOR THE WEEKEND...WITH A WARMING TREND BRINGING TEMPERATURES
BACK TO NEAR NORMAL AS HIGH PRESSURE DOMINATES FOR THE FIRST HALF
OF THE WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 350 PM EDT THU SEP 10 2015
WEAK HIGH PRESSURE CONTINUES OVER THE REGION THIS AFTERNOON.
SCATTERED CONVECTION PERSISTING OVER NORTHERN ILLINOIS IN VICINITY OF
AN UPPER LEVEL WAVE. HAVE SEEN SOME CU FORMATION THIS AFTERNOON BUT
IN GENERAL...SEEING GOOD DEAL OF SUNSHINE WITH SEASONABLE TEMPS IN
THE LOWER 80S.
FOCUS OF THE NEAR TERM REMAINS ON THE APPROACHING COLD FRONT AND
UPPER WAVE WITH A GROWING CHANCE FOR RAIN SHOWERS AS THE NIGHT
PROGRESSES. INITIAL BATCH OF CONVECTION OVER NORTHERN ILLINOIS
MOVING EAST-SOUTHEAST. EXTRAPOLATION WOULD BRING THESE STORMS INTO
THE NORTHERN WABASH VALLEY BY 22-23Z. THIS ALIGNS WELL WITH HRRR AND
WRF HI-RES GUIDANCE. WITH THE AIRMASS QUITE A BIT MORE STABLE OVER
THE FORECAST AREA THOUGH...EXPECT CURRENT INTENSITY TO STORMS TO
DIMINISH CONSIDERABLY AS THEY APPROACH NORTHWEST COUNTIES...LIKELY
DISSIPATING THIS EVENING. AT THIS POINT...THIS WOULD ONLY WARRANT
LOW CHANCE POPS OVER NORTHWEST COUNTIES WITH DRY CONDITIONS
CONTINUING ELSEWHERE.
ONCE THE CONVECTION DIMINISHES...EXPECT A RELATIVELY QUIET NIGHT
WITH MOST RAIN HOLDING OFF UNTIL THE PREDAWN HOURS AS THE FRONTAL
BOUNDARY NEARS THE REGION. WILL GRADUALLY INCREASE POPS LATE TONIGHT
GENERALLY NORTHWEST OF A SULLIVAN-INDY METRO-MUNCIE LINE WITH DRY
WEATHER PERSISTING OVER THE SOUTHEAST HALF OF THE FORECAST AREA.
TEMPS...SUBTLE WARM ADVECTION AHEAD OF THE FRONT WILL KEEP TEMPS
MILD OVERNIGHT. MOS GUIDANCE MATCHED WITH LOW LEVEL THERMALS WELL
AND UTILIZED A BLEND. EXPECT LOWS RANGING FORM THE UPPER 50S TO
LOWER 60S.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 350 PM EDT THU SEP 10 2015
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH SATURDAY...ALONG
WITH TEMPS THROUGHOUT THE PERIOD.
FIRST TRUE BLAST OF FALL WEATHER POISED TO VISIT THE OHIO VALLEY
OVER THE WEEKEND AS A SHARP UPPER TROUGH POSITIONS ITSELF OVER THE
REGION. PRIOR TO THIS...WIDESPREAD RAIN SHOWERS ARE EXPECTED TO
ACCOMPANY THE COLD FRONT AS IT SWINGS ACROSS CENTRAL INDIANA ON
FRIDAY. AXIS OF LOW LEVEL CONVERGENCE COMBINED WITH DIFFLUENCE ALOFT
AND POCKETS OF ISENTROPIC LIFT ALL SUPPORT A GOOD THREAT FOR RAIN
SHOWERS...ESPECIALLY FROM LATE MORNING THROUGH THE AFTERNOON. DESPITE
WEAK INSTABILITY ON FRIDAY...FEEL ISOLATED THUNDER MENTION IS
WARRANTED WITH MODEL SOUNDINGS EXHIBITING A FEW HOURS OF STEEPER
LAPSE RATES DURING THE AFTERNOON.
QUITE POSSIBLE THAT THE GREATER CONVECTIVE THREAT COMES WITH THE
TRAILING UPPER WAVE OVER THE WESTERN GREAT LAKES WITH STORMS
DEVELOPING ON THE EDGE OF THE APPROACHING COLD POOL ALOFT. MOST OF
THIS ACTIVITY SHOULD STAY NORTHWEST OF THE FORECAST AREA PRIOR TO
FRIDAY EVENING...BUT THINK THE ARRIVAL OF THIS FEATURE COULD PROLONG
THE PRECIP THREAT OVER PARTS OF THE FORECAST AREA THROUGH MUCH OF
FRIDAY EVENING EVEN AS WHAT LITTLE INSTABILITY PRESENT DIMINISHES.
THE UPPER TROUGH WILL AMPLIFY OVER THE REGION SATURDAY AS TWO
SEPARATE VORTS DIVE INTO THE BASE OF THE TROUGH. COMBINED WITH
STRENGTHENING COLD ADVECTION AS THE COLD POOL EXPANDS SOUTH INTO
INDIANA...SATURDAY WILL HAVE A VERY AUTUMN-LIKE FEEL TO IT WITH
PLENTY OF CLOUDS AND BREEZY NORTHERLY WINDS. CANNOT RULE OUT A FEW
INSTABILITY SHOWERS AS WELL WITH THE ENERGY ALOFT SWINGING THROUGH
AND WILL MAINTAIN LOW CHANCE POPS. SKIES SHOULD GRADUALLY CLEAR
SATURDAY NIGHT AS THE UPPER TROUGH SLOWLY SHIFTS EAST AND HIGH
PRESSURE BUILDS IN FROM THE WEST. SUNDAY WILL SEE MUCH MORE IN THE
WAY OF SUNSHINE AS THE HIGH EXPANDS EAST AND SURFACE WINDS BACK TO A
MORE WESTERLY DIRECTION.
TEMPS...GENERALLY LEANED CLOSER TO COOLER MAVMOS GUIDANCE FOR FRIDAY
HIGHS WITH CLOUDS AND PRECIP IN ABUNDANCE. NEAR THE COOL END OF MOS
FOR SATURDAY AS HIGHS WILL BE ONLY IN THE 60S...AND MAY STRUGGLE TO
CLIMB OUT OF THE LOWER 60S IN SOME AREAS WHICH IS WELL SUPPORTED BY
LOW LEVEL THERMALS. TEMPS WILL BEGIN TO RECOVER ON SUNDAY AS THE
COLD POOL SHIFTS EAST...RANGING FROM THE MID 60S EAST TO NEAR 70
WEST. CHILLY NIGHTS ON THE HORIZON THROUGH THE PERIOD...HIGHLIGHTED
BY WHAT WILL LIKELY BE THE COLDEST NIGHT IN NEARLY FOUR MONTHS FOR
MANY. EXPECT LOWS IN THE 40S BOTH MORNINGS ON THE WEEKEND WITH
SUNDAY MORNING BEING THE COLDEST AS SKIES CLEAR AND WINDS DIMINISH.
UNDERCUT MOS SLIGHTLY SUNDAY MORNING AS NORMAL COOL SPOTS MAY FALL
AS LOW AS THE LOWER 40S. LOCATION OF THE HIGH CENTER TO THE WEST
HOWEVER MAY KEEP LOWER LEVELS FROM FULLY DECOUPLING AND KEEPING
TEMPS FROM COMPLETELY BOTTOMING OUT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU SEP 10 2015
REGIONAL INITIALIZATION LOOKS GOOD.
UPPER LEVEL RIDGING WILL MOVE INTO THE AREA SUNDAY NIGHT AND PERSIST
THROUGH WEDNESDAY...KEEPING THE WEATHER DRY. THEN TROUGHING FROM A
LOW PRESSURE SYSTEM OVER CANADA AND AN ASSOCIATED COLD FRONT WILL
APPROACH FROM THE NORTHWEST. THIS WILL BRING SLIGHT CHANCES FOR RAIN
SHOWERS AND THUNDERSTORMS BACK TO THE FORECAST WEDNESDAY
NIGHT...WITH BETTER CHANCES DURING THE DAY ON THURSDAY.
THE PERIOD WILL BEGIN WITH BELOW NORMAL TEMPERATURES IN THE UPPER
40S FOR LOWS AND LOW 70S FOR AFTERNOON HIGHS...BEFORE REBOUNDING TO
SEASONAL NORMALS AS THE RIDGE MOVES INTO PLACE. AS THE RIDGING
PERSISTS...TEMPERATURES WILL THEN INCREASE TO ABOVE SEASONAL NORMALS
FOR MID WEEK WITH HIGHS IN THE LOW 80S AND LOWS IN THE MID TO UPPER
60S.
&&
.AVIATION /DISCUSSION FOR 102100Z IND TAF UPDATE/...
ISSUED AT 430 PM EDT THU SEP 10 2015
NO CHANGES NEEDED TO THE TAF.
PREVIOUS DISCUSSION FOLLOWS...
ISSUED AT 1259 PM EDT THU SEP 10 2015
VFR EXPECTED THROUGH MOST OF THE PERIOD. SCATTERED TO BROKEN CU
ABOVE 3 KFT WILL LAST THROUGH THE DAY. A LINE OF THUNDERSTORMS
CURRENTLY OVER NORTHERN ILLINOIS COULD DEVELOP ENOUGH ON THE
SOUTHERN END AND MOVE EAST ENOUGH TO IMPACT KLAF BEFORE THEY FALL
APART THIS EVENING...BUT CONFIDENCE IN THIS IS FAIRLY LOW SO WILL
JUST INCLUDE A VCSH FOR A FEW HOURS AFTER 0Z. THEN SHOULD SEE A
BREAK UNTIL MUCH LATER DURING THE OVERNIGHT OR EVEN FRIDAY MORNING
WHEN RAIN WILL MOVE INTO THE SITES ALONG AND BEHIND THE SECONDARY
COLD FRONT. FROM FORECAST SOUNDINGS AND TIME HEIGHTS LOOKS LIKE
CEILINGS WILL BE MVFR WITH THESE SHOWERS SO WILL INTRODUCE THOSE
CONDITIONS NEAR THE END OF THE TAF PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM...MMB/CP
AVIATION...CP/MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
350 PM EDT THU SEP 10 2015
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW
&&
.SYNOPSIS...
ISSUED AT 350 PM EDT THU SEP 10 2015
CHANCES FOR RAIN WILL INCREASE LATE TONIGHT THROUGH FRIDAY AS A COLD
FRONT MOVES THROUGH THE AREA. MUCH COOLER FALL-LIKE WEATHER WILL
FOLLOW FOR THE WEEKEND...WITH A WARMING TREND BRINGING TEMPERATURES
BACK TO NEAR NORMAL AS HIGH PRESSURE DOMINATES FOR THE FIRST HALF
OF THE WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 350 PM EDT THU SEP 10 2015
WEAK HIGH PRESSURE CONTINUES OVER THE REGION THIS AFTERNOON.
SCATTERED CONVECTION PERSISTING OVER NORTHERN ILLINOIS IN VICINITY OF
AN UPPER LEVEL WAVE. HAVE SEEN SOME CU FORMATION THIS AFTERNOON BUT
IN GENERAL...SEEING GOOD DEAL OF SUNSHINE WITH SEASONABLE TEMPS IN
THE LOWER 80S.
FOCUS OF THE NEAR TERM REMAINS ON THE APPROACHING COLD FRONT AND
UPPER WAVE WITH A GROWING CHANCE FOR RAIN SHOWERS AS THE NIGHT
PROGRESSES. INITIAL BATCH OF CONVECTION OVER NORTHERN ILLINOIS
MOVING EAST-SOUTHEAST. EXTRAPOLATION WOULD BRING THESE STORMS INTO
THE NORTHERN WABASH VALLEY BY 22-23Z. THIS ALIGNS WELL WITH HRRR AND
WRF HI-RES GUIDANCE. WITH THE AIRMASS QUITE A BIT MORE STABLE OVER
THE FORECAST AREA THOUGH...EXPECT CURRENT INTENSITY TO STORMS TO
DIMINISH CONSIDERABLY AS THEY APPROACH NORTHWEST COUNTIES...LIKELY
DISSIPATING THIS EVENING. AT THIS POINT...THIS WOULD ONLY WARRANT
LOW CHANCE POPS OVER NORTHWEST COUNTIES WITH DRY CONDITIONS
CONTINUING ELSEWHERE.
ONCE THE CONVECTION DIMINISHES...EXPECT A RELATIVELY QUIET NIGHT
WITH MOST RAIN HOLDING OFF UNTIL THE PREDAWN HOURS AS THE FRONTAL
BOUNDARY NEARS THE REGION. WILL GRADUALLY INCREASE POPS LATE TONIGHT
GENERALLY NORTHWEST OF A SULLIVAN-INDY METRO-MUNCIE LINE WITH DRY
WEATHER PERSISTING OVER THE SOUTHEAST HALF OF THE FORECAST AREA.
TEMPS...SUBTLE WARM ADVECTION AHEAD OF THE FRONT WILL KEEP TEMPS
MILD OVERNIGHT. MOS GUIDANCE MATCHED WITH LOW LEVEL THERMALS WELL
AND UTILIZED A BLEND. EXPECT LOWS RANGING FORM THE UPPER 50S TO
LOWER 60S.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 350 PM EDT THU SEP 10 2015
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH SATURDAY...ALONG
WITH TEMPS THROUGHOUT THE PERIOD.
FIRST TRUE BLAST OF FALL WEATHER POISED TO VISIT THE OHIO VALLEY
OVER THE WEEKEND AS A SHARP UPPER TROUGH POSITIONS ITSELF OVER THE
REGION. PRIOR TO THIS...WIDESPREAD RAIN SHOWERS ARE EXPECTED TO
ACCOMPANY THE COLD FRONT AS IT SWINGS ACROSS CENTRAL INDIANA ON
FRIDAY. AXIS OF LOW LEVEL CONVERGENCE COMBINED WITH DIFFLUENCE ALOFT
AND POCKETS OF ISENTROPIC LIFT ALL SUPPORT A GOOD THREAT FOR RAIN
SHOWERS...ESPECIALLY FROM LATE MORNING THROUGH THE AFTERNOON. DESPITE
WEAK INSTABILITY ON FRIDAY...FEEL ISOLATED THUNDER MENTION IS
WARRANTED WITH MODEL SOUNDINGS EXHIBITING A FEW HOURS OF STEEPER
LAPSE RATES DURING THE AFTERNOON.
QUITE POSSIBLE THAT THE GREATER CONVECTIVE THREAT COMES WITH THE
TRAILING UPPER WAVE OVER THE WESTERN GREAT LAKES WITH STORMS
DEVELOPING ON THE EDGE OF THE APPROACHING COLD POOL ALOFT. MOST OF
THIS ACTIVITY SHOULD STAY NORTHWEST OF THE FORECAST AREA PRIOR TO
FRIDAY EVENING...BUT THINK THE ARRIVAL OF THIS FEATURE COULD PROLONG
THE PRECIP THREAT OVER PARTS OF THE FORECAST AREA THROUGH MUCH OF
FRIDAY EVENING EVEN AS WHAT LITTLE INSTABILITY PRESENT DIMINISHES.
THE UPPER TROUGH WILL AMPLIFY OVER THE REGION SATURDAY AS TWO
SEPARATE VORTS DIVE INTO THE BASE OF THE TROUGH. COMBINED WITH
STRENGTHENING COLD ADVECTION AS THE COLD POOL EXPANDS SOUTH INTO
INDIANA...SATURDAY WILL HAVE A VERY AUTUMN-LIKE FEEL TO IT WITH
PLENTY OF CLOUDS AND BREEZY NORTHERLY WINDS. CANNOT RULE OUT A FEW
INSTABILITY SHOWERS AS WELL WITH THE ENERGY ALOFT SWINGING THROUGH
AND WILL MAINTAIN LOW CHANCE POPS. SKIES SHOULD GRADUALLY CLEAR
SATURDAY NIGHT AS THE UPPER TROUGH SLOWLY SHIFTS EAST AND HIGH
PRESSURE BUILDS IN FROM THE WEST. SUNDAY WILL SEE MUCH MORE IN THE
WAY OF SUNSHINE AS THE HIGH EXPANDS EAST AND SURFACE WINDS BACK TO A
MORE WESTERLY DIRECTION.
TEMPS...GENERALLY LEANED CLOSER TO COOLER MAVMOS GUIDANCE FOR FRIDAY
HIGHS WITH CLOUDS AND PRECIP IN ABUNDANCE. NEAR THE COOL END OF MOS
FOR SATURDAY AS HIGHS WILL BE ONLY IN THE 60S...AND MAY STRUGGLE TO
CLIMB OUT OF THE LOWER 60S IN SOME AREAS WHICH IS WELL SUPPORTED BY
LOW LEVEL THERMALS. TEMPS WILL BEGIN TO RECOVER ON SUNDAY AS THE
COLD POOL SHIFTS EAST...RANGING FROM THE MID 60S EAST TO NEAR 70
WEST. CHILLY NIGHTS ON THE HORIZON THROUGH THE PERIOD...HIGHLIGHTED
BY WHAT WILL LIKELY BE THE COLDEST NIGHT IN NEARLY FOUR MONTHS FOR
MANY. EXPECT LOWS IN THE 40S BOTH MORNINGS ON THE WEEKEND WITH
SUNDAY MORNING BEING THE COLDEST AS SKIES CLEAR AND WINDS DIMINISH.
UNDERCUT MOS SLIGHTLY SUNDAY MORNING AS NORMAL COOL SPOTS MAY FALL
AS LOW AS THE LOWER 40S. LOCATION OF THE HIGH CENTER TO THE WEST
HOWEVER MAY KEEP LOWER LEVELS FROM FULLY DECOUPLING AND KEEPING
TEMPS FROM COMPLETELY BOTTOMING OUT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU SEP 10 2015
REGIONAL INITIALIZATION LOOKS GOOD.
UPPER LEVEL RIDGING WILL MOVE INTO THE AREA SUNDAY NIGHT AND PERSIST
THROUGH WEDNESDAY...KEEPING THE WEATHER DRY. THEN TROUGHING FROM A
LOW PRESSURE SYSTEM OVER CANADA AND AN ASSOCIATED COLD FRONT WILL
APPROACH FROM THE NORTHWEST. THIS WILL BRING SLIGHT CHANCES FOR RAIN
SHOWERS AND THUNDERSTORMS BACK TO THE FORECAST WEDNESDAY
NIGHT...WITH BETTER CHANCES DURING THE DAY ON THURSDAY.
THE PERIOD WILL BEGIN WITH BELOW NORMAL TEMPERATURES IN THE UPPER
40S FOR LOWS AND LOW 70S FOR AFTERNOON HIGHS...BEFORE REBOUNDING TO
SEASONAL NORMALS AS THE RIDGE MOVES INTO PLACE. AS THE RIDGING
PERSISTS...TEMPERATURES WILL THEN INCREASE TO ABOVE SEASONAL NORMALS
FOR MID WEEK WITH HIGHS IN THE LOW 80S AND LOWS IN THE MID TO UPPER
60S.
&&
.AVIATION /DISCUSSION FOR 101800Z TAF ISSUANCE/...
ISSUED AT 1259 PM EDT THU SEP 10 2015
VFR EXPECTED THROUGH MOST OF THE PERIOD. SCATTERED TO BROKEN CU
ABOVE 3 KFT WILL LAST THROUGH THE DAY. A LINE OF THUNDERSTORMS
CURRENTLY OVER NORTHERN ILLINOIS COULD DEVELOP ENOUGH ON THE
SOUTHERN END AND MOVE EAST ENOUGH TO IMPACT KLAF BEFORE THEY FALL
APART THIS EVENING...BUT CONFIDENCE IN THIS IS FAIRLY LOW SO WILL
JUST INCLUDE A VCSH FOR A FEW HOURS AFTER 0Z. THEN SHOULD SEE A
BREAK UNTIL MUCH LATER DURING THE OVERNIGHT OR EVEN FRIDAY MORNING
WHEN RAIN WILL MOVE INTO THE SITES ALONG AND BEHIND THE SECONDARY
COLD FRONT. FROM FORECAST SOUNDINGS AND TIME HEIGHTS LOOKS LIKE
CEILINGS WILL BE MVFR WITH THESE SHOWERS SO WILL INTRODUCE THOSE
CONDITIONS NEAR THE END OF THE TAF PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM...MMB/CP
AVIATION...CP
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1233 PM CDT THU SEP 10 2015
.UPDATE...
ISSUED AT 1226 PM CDT THU SEP 10 2015
THE CONVECTION THAT DEVELOPED THIS MORNING IS STARTING TO EXIT THE
AREA. THE QUESTION NOW IS HOW QUICKLY CAN THE ATMOSPHERE RECOVER
AHEAD OF THE APPROACHING COLD FRONT. SATELLITE/OBSERVATIONS PLACES
THE COLD FRONT ROUGHLY ALONG THE MN/IA BORDER.
IF THE INTERNAL TRENDS OF THE RAP ARE CORRECT...A NEW ROUND OF
CONVECTION SHOULD BEGIN DEVELOPING DURING PEAK HEATING WITH AREAS
ALONG/SOUTH OF I-80 BEING FAVORED.
&&
.SYNOPSIS...
ISSUED AT 325 AM CDT THU SEP 10 2015
SURFACE HIGH PRESSURE RIDGE IS RETREATING TOWARD THE GREAT LAKES
AHEAD OF ADVANCING COLD FRONT FROM NORTHERN WI THROUGH SOUTHWEST
MN AND SOUTHERN SD. LIGHT SOUTHERLY RETURN FLOW ON BACKSIDE OF
DEPARTING HIGH USHERING IN MOISTURE WITH SURFACE DEWPTS CLIMBING
INTO THE LOWER 60S WEST/SOUTHWEST CWA. THIS COMBINED WITH INCREASE
IN CLOUDINESS RESPONSIBLE FOR MILDER START IN THE LOWER TO MIDDLE
60S MANY AREAS WITH FEW LOCATIONS IN THE UPPER 50S/NEAR 60 EAST OF
THE MISSISSIPPI. UPPER LEVEL DISTURBANCE PASSING TO OUR NORTH
ALONG WITH RIGHT ENTRANCE REGION OF GREAT LAKES H3 JET AIDING IN
BETTER COVERAGE OF SHOWERS AND A FEW STORMS OVER FAR NORTHEAST IA
INTO WI. MEANWHILE...MINI STORM COMPLEX OVER NORTHEAST KS
OCCURRING ON NOSE OF THETA-E ADVECTION ON 20+ KT 850-800 VEERING
WIND MAX. IN THE VERY SHORT TERM... AREA WILL BE LARGELY SPLIT BY
BOTH MECHANISMS WITH POTENTIAL FOR ISOLD-SCT SHOWERS SKIRTING
NORTHERN COUNTIES ATTENDANT TO PASSING WAVE AND UPPER
DIVERGENCE... WHILE SPRINKLES OR LIGHT SHOWER MAY OCCUR SOUTHERN
PORTIONS OF CWA BLEEDING OFF KS CONVECTIVE PROCESSES AND REMNANT
DECAYING 850-800 JET. WILL CONTINUE TO SEE CHANCES FOR SHOWERS AND
A FEW STORMS NEXT 12-18 HOURS UNTIL PASSAGE OF COLD FRONT LATER
TDY INTO THIS EVENING. THE COLD FRONT WILL BRING A FALL PREVIEW
WITH A REINFORCING SHOT OF EVEN COOLER AIR FOR FRI LINGERING INTO
THE WEEKEND.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 325 AM CDT THU SEP 10 2015
WILL CONTINUE WITH CHANCES FOR SHOWERS AND A FEW STORMS TDY TAPERING
OFF LATE PM THROUGH EVE FROM NW TO SE WITH PASSAGE OF COLD FRONT.
GENERALLY STAYED WITH PREVIOUS FORECAST OF KEEPING POPS AND QPF
BELOW GUIDANCE DUE TO A FEW CONCERNS LEADING TO UNCERTAINTY... 1)
CWA INITIALLY MOSTLY SPLIT THIS AM WITH BETTER FORCING NORTH AND
SOUTH OF CWA... 2) 850 MB FLOW SHOWN TO VEER TO WESTERLY TDY LENDING
TO DECAYING CONVERGENCE IN WAKE OF PASSING DISTURBANCE TO OUR NORTH...
NEVER A GOOD SIGN FOR ANY ORGANIZED PCPN... AND 3) CWA IS SHOWN TO
RESIDE SQUARELY IN THE UPPER JET AXIS LATER TDY AND THIS EVE AGAIN NOT
A GREAT LOCATION TO BE FOR ORGANIZED PCPN. THE RIGHT ENTRANCE REGION
OF THIS UPPER JET AND COLD FRONT THOUGH LOOK TO AID IN BLOSSOMING OF
CONVECTION LATE THIS AFTN TO OUR SOUTHWEST OVER PORTIONS OF KS...NE
POSSIBLY INTO SOUTHWEST IA AND NORTHWEST MO. STEERING FLOW FROM THE
WEST/NORTHWEST AND ORIENTATION OF MOIST AXIS SUPPORTS MOST OF THIS
ACTIVITY SCOOTING JUST SOUTH OF CWA. OVERALL... ATTIM LOOKS LIKE JUST
SPOTTY PRECIP TDY INTO THIS EVE.
AS FOR TEMPS... HIGHS TDY WILL BE CHALLENGING WITH TEMPS MODULATED
BY THE CLOUDS AND ANY PRECIP AND EVAPORATIONAL COOLING FROM THE
PRECIP PROCESSES. AREAS THAT SEE ANY FILTERED SUNSHINE SHOULD SEE
HIGHS AROUND 80... WHILE AREAS THAT REMAIN CLOUDY SHOULD SEE HIGHS
ONLY IN THE LOWER TO MIDDLE 70S. MUCH COOLER LOWS TONIGHT POST-FRONTAL
WITH UPPER 40S NORTH TO UPPER 50S SOUTH...AND WOULD NOT BE SURPRISED
IF THESE NEED TO BE LOWERED 1-3 DEGS BASED ON VERIFICATION OF
MODEL TEMPS AND OBS EARLY THIS AM. THE COOLER AIR WILL BE USHERED
IN ON GUSTY NORTH WINDS OF 10-20 MPH. SHOULD ALSO SEE GRADUAL
CLEARING NW OVERNIGHT SPREADING SE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 325 AM CDT THU SEP 10 2015
FORECAST FOCUS ON VERY COOL TEMPERATURES THROUGH THIS WEEKEND THEN A
WARM-UP FOR THE FIRST HALF OF NEXT WEEK. MAINLY A DRY PERIOD ALSO.
FRIDAY...MUCH COOLER IN THE WAKE OF THE COLD FRONT THAT WOULD HAVE
ALREADY EXITED THE DVN CWA. COLD AIR ADVECTION WILL PRODUCE SOME
OCCASIONAL LOW CLOUDS ALONG WITH GUSTY NORTH WINDS TO 20 TO 25 MPH.
THIS WILL MAKE FOR A VERY COOL DAY WITH MAXIMUM TEMPERATURES IN THE
MID TO UPPER 60S AT MOST LOCATIONS.
FRIDAY NIGHT THROUGH SUNDAY...DELIGHTFUL AUTUMN-LIKE WEATHER IS IN
STORE AS DEEP UPPER LEVEL TROUGH SHIFTS SLOWLY EASTWARD AND SURFACE
HIGH PRESSURE BUILDS INTO THE AREA. MAINLY CLEAR SKIES EXPECTED
THROUGH THE WEEKEND. HIGHS WILL BE IN THE MID 60S SATURDAY AND
AROUND 70 ON SUNDAY. LOWS SHOULD BOTTOM OUT IN THE 40S AT MOST
LOCATIONS. THERE IS STILL THE POTENTIAL OVER THE WEEKEND FOR A FEW
FAVORED VALLEY/SHELTERED LOCATIONS TO DIP INTO THE UPPER 30S WHERE
WINDS CAN REMAIN CALM FOR SEVERAL HOURS.
MONDAY THROUGH WEDNESDAY...A DRAMATIC WARM-UP AS THE TROUGH IN THE
EAST LIFTS WELL TO THE NORTHEAST ONLY TO BE REPLACED BY ANOTHER DEEP
TROUGH...BUT THIS TIME IN THE WESTERN UNITED STATES. THE UPPER LEVEL
FLOW WILL BECOME SOUTHWEST ACROSS THE MIDWEST ALLOWING FOR MUCH
WARMER TEMPERATURES FOR THE FIRST HALF THE WEEK. WITH RIDGING ALONG
THE GULF COAST THIS WILL PREVENT THE GULF MOISTURE FROM RETURNING
NORTHWARD. HIGHS WILL BE WARMING WELL INTO THE 70S ON MONDAY AND IN
THE LOWER TO MID 80S TUESDAY AND WEDNESDAY. DEPENDING ON CLOUD
TRENDS AND IF DEEPER MIXING CAN OCCUR THEN READINGS MAY APPROACH 90
IN OUR NW CWA...WITH 850 MB TEMPERATURES PROGGED TO 20C.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1226 PM CDT THU SEP 10 2015
INITIAL CONVECTION IS MOVING INTO NORTHERN ILLINOIS WITH THE
EXCEPTION OF SOME CONVECTION APPROACHING KDBQ. THERE ARE QUESTIONS
ON HOW CONVECTION WILL DEVELOP/EVOLVE THIS AFTERNOON WHICH IS
TIED TO HOW QUICKLY THE ATMOSPHERE CAN RECOVER. MAINLY VFR
CONDITIONS ARE EXPECTED THROUGH 01Z/11. IF A SHRA OR TSRA AFFECTS
A TAF SITE...A BRIEF PERIOD OF MVFR OR EVEN IFR CONDITIONS IS
VERY POSSIBLE. AFT 01Z/11 VFR CONDITIONS ARE EXPECTED AS HIGH
PRESSURE BUILDS INTO THE MIDWEST.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...05
SHORT TERM...05
LONG TERM...HAASE
AVIATION...08
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
234 PM CDT THU SEP 10 2015
.DISCUSSION...
FRONTAL BOUNDARY CONTINUES TO BE VERY DIFFUSE LATE THIS AFTERNOON
BUT THE LOWER DEWPOINTS ACROSS NORTHERN LOUISIANA SUGGESTS THAT
PERHAPS THE BOUNDARY HAS MIXED A LITTLE SOUTH OF THE I-20 CORRIDOR
ATTM. SHOWERY CONVECTION FOR THE MOST PART HAS BEEN CONFINED TO
AREAS SOUTH OF THE I-20 CORRIDOR...OR ACROSS DEEP EAST TEXAS INTO
PORTIONS OF WEST CENTRAL AND EAST CENTRAL LA. FOR TONIGHT... HAVE
MAINTAINED CHANCE POPS ACROSS OUR SOUTHERN ZONES WITH SLIGHT
CHANCE POPS COVERING THE I-20 CORRIDOR JUST IN CASE SOMETHING WERE
TO IGNITE ALONG THE FRONT WHICH THE 12Z NAM STILL SUGGESTS MIGHT
HAPPEN EVEN THOUGH THE HRRR HAS BACKED OFF THIS SCENARIO.
THIS BOUNDARY WILL CONTINUE TO SERVE AS A FOCUS FOR CONVECTION
DURING THE DAY FRIDAY AND GIVEN THE STEEP MID LEVEL LAPSE RATES
AND MODERATE INSTABILITY EXPECTED SOUTH OF THE CORRIDOR ON
FRIDAY...CANNOT RULE OUT AN ISOLATED STRONG TO SEVERE STORM
OR TWO DURING PEAK HEATING. IN ADDITION...SHORTWAVE ENERGY
DROPPING QUICKLY OUT OF THE CENTRAL PLAINS INTO THE SOUTHERN
PLAINS/MID MISS VALLEY WILL PROVIDE THE UPPER LEVEL SUPPORT
NECESSARY FOR INCREASING SHOWERS AND THUNDERSTORMS MOVING INTO OUR
REGION FROM THE NORTHWEST. THIS WILL BE THE LEADING EDGE OF THE
MUCH COOLER AND DRIER WEATHER FORECAST FOR THE UPCOMING WEEKEND.
THE I-20 CORRIDOR WILL LIKELY ENCOUNTER THIS FRONTAL FORCING BY
LATE AFTERNOON/EARLY EVENING...THUS THE POSSIBILITY OF A STRONG
STORM LATE IN THE DAY. KEPT POPS AT HIGH END CHANCE CATEGORY FOR
FRIDAY EVENING WITH THE CONVECTION LIKELY DISSIPATING AFTER
MIDNIGHT WITH THE COOLER/DRIER AIR FOLLOWING FROM THE NORTH.
COULD SEE TEMPERATURES IN THE UPPER 50S FOR LOWS SATURDAY MORNING
WITH HIGHS ON SATURDAY RANGING IN THE 80S WITH MUCH DRIER
DEWPOINTS. THE COOLEST MORNING SHOULD BE SUNDAY WITH WIDESPREAD
50S AREAWIDE AND I WOULD NOT BE SURPRISED TO SEE UPPER 40S ACROSS
OUR MOST PROTECTED NORTHERN ZONES. RECORDS MAY FALL IF THIS
OCCURS.
TEMPERATURES SHOULD BEGIN TO MODERATE BY THE FIRST OF NEXT WEEK AS
WE SEE RETURNING SOUTHERLY FLOW SETTING UP. ALOFT...WE WILL
TRANSITION FROM A NORTHERLY FLOW...TO ZONAL...AND EVENTUAL
SOUTHWEST FLOW AS THE NEXT LONGWAVE TROUGH MOVES ONSHORE THE
PACIFIC NORTHWEST. WITH UPPER RIDGING FCST TO SETUP ACROSS THE MID
ATLANTIC BY THE MIDDLE PART OF NEXT WEEK...WE SHOULD BEGIN TO SEE
AT LEAST WIDELY SCATTERED AFTERNOON/EVENING VARIETY CONVECTION
WITH A RETURN TO NEAR NORMAL TEMPERATURES.
PRELIMS TO FOLLOW...13.
&&
.PREV DISCUSSION... /ISSUED 1254 PM CDT THU SEP 10 2015/
AVIATION...
FOR THE 10/18Z TAFS...A QUASI-STATIONARY COLD FRONT IS LOCATED
ROUGHLY PARALLEL TO AND JUST NORTH OF I-20. ISOLATED TO WIDELY
SCATTERED CONVECTION IS QUICKLY DEVELOPING SOUTH OF THE FRONT.
SHWRS/TSTMS WILL LIKELY AFFECT LOCATIONS ALONG AND SOUTH OF I-20.
DID NOT INCLUDE A MENTION OF PRECIP AT KSHV AS DEVELOPMENT IS MORE
UNCERTAIN BUT WILL MONITOR CLOSELY. SHWRS/TSTMS SHOULD GRADUALLY
DISSIPATE AFTER 11/00Z. MVFR/IFR CIGS/VSBYS ARE EXPECTED TO ONCE
AGAIN DEVELOP ACROSS MOST OF THE AREA DURING THE OVERNIGHT/EARLY
MORNING HRS. WHILE THIS FIRST COLD FRONT DISSIPATES...A SECOND
FRONT WILL MOVE INTO THE AREA DURING THE DAY FRIDAY. MORE PRECIP
IS POSSIBLE AHEAD OF THIS NEXT FRONT SOUTH OF I-20. /09/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 73 92 65 84 / 20 30 50 10
MLU 70 92 66 84 / 20 20 50 10
DEQ 66 89 58 81 / 10 40 20 0
TXK 69 91 61 81 / 10 30 40 0
ELD 66 90 60 79 / 10 30 40 0
TYR 73 92 65 84 / 20 30 50 10
GGG 71 92 65 83 / 20 30 50 10
LFK 73 92 69 87 / 30 30 50 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
09/13
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
321 PM EDT THU SEP 10 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT THU SEP 10 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A TROF EXTENDING S INTO
THE NCNTRL STATES AND UPPER GREAT LAKES...ANCHORED BY A MID LEVEL
LOW OVER NRN ONTARIO. SHORTWAVE MOVING ACROSS NRN ONTARIO IS HELPING
TO DRIVE A COLD FRONT SE...CURRENTLY ACROSS WRN LAKE SUPERIOR. DEEP
LAYER FORCING PER QVECTORS IS SUPPORTING AN AREA OF SHRA MOVING
ACROSS NE WI INTO SCNTRL UPPER MI EARLY THIS MORNING. ISOLD SHRA
HAVE BEEN OCCURRING FARTHER N TO LAKE SUPERIOR. EVEN A TSTM WAS
NOTED OVER ERN LAKE SUPERIOR A FEW HRS AGO.
AS FORCING SUPPORTING THE NE WI PCPN SHIFTS E...THIS MORE ORGANIZED
SHRA AREA WILL MOVE ACROSS THE SCNTRL AND PORTIONS OF THE ERN FCST
AREA OVER THE NEXT FEW HRS. THIS MAIN AREA OF PCPN SHOULD BE E OF
THE AREA NO LATER THAN MID MORNING. WITH COLD FRONT STILL PUSHING
SE...POTENTIAL IS THERE FOR ADDITIONAL ISOLD TO SCT SHRA DEVELOPMENT
UNTIL FROPA. THIS POTENTIAL SHOULD INCREASE DURING THE AFTN AS SOME
INSTABILITY BUILDS UP AHEAD OF COLD FRONT. DEVELOPING LAKE BREEZE
OFF LAKE MICHIGAN WILL ALSO STRENGTHEN THE LOW-LEVEL CONVERGENCE
ALONG THE SE MOVING COLD FRONT. RAP AND GFS SHOW MLCAPES UPWARDS OF
200-300J/KG OVER THE SCNTRL/SE FCST AREA. 00Z NAM SHOWED MLCAPE OVER
1000J/KG. WHILE THE 06Z NAM HAS PULLED BACK TO 600-800J/KG...IT
STILL LOOKS OVERDONE. IN ANY EVENT...THE AVBL INSTABILITY SUGGESTS
THE POTENTIAL FOR ISOLD TSTMS OVER THE SCNTRL/SE FCST AREA THIS AFTN
ALONG/AHEAD OF COLD FRONT.
CAA TODAY/TONIGHT WILL DROP 850MB TEMPS DOWN TO 0 TO 2C OVER LAKE
SUPERIOR BY 12Z FRI...SUFFICIENT FOR LAKE EFFECT PROCESSES WITH
WATER TEMPS ROUGHLY 15-18C. WITH NAM/GFS FCST SOUNDINGS SHOWING A
WELL MIXED LAYER IN LOWER 2KFT OF THE AIR MASS...BELIEVE IT WILL
TAKE SOME TIME TO GET LAKE EFFECT GOING TONIGHT...ESPECIALLY IN
LIGHT OF THE LACK OF SYNOPTIC SUPPORT WITH DEEP LAYER QVECTOR
DIVERGENCE DOMINATING. NOT EXPECTING ANYTHING MORE THAN ISOLD TO
PERHAPS SCT -SHRA COVERAGE. WITH WATER TEMPS MORE IN THE 12-15C
RANGE OVER THE ERN LAKE...-SHRA COVERAGE WILL BE LEAST OVER THE ERN
FCST AREA. IN FACT...THERE MAY NOT BE ANY LAKE EFFECT -SHRA OVER THE
FAR E TONIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 319 PM EDT THU SEP 10 2015
THE LONG TERM FORECAST WILL START ON THE COOL SIDE...BUT
TEMPERATURES WILL MODERATE FOR THE SECOND HALF OF THE WEEKEND AND
BE ABOVE NORMAL FOR MOST OF NEXT WEEK. THE PERIOD OF BELOW NORMAL
TEMPERATURES OVER THE GREAT LAKES REGION WILL BE TIED TO THE UPPER
TROUGH THAT WILL BE OVER THE AREA AT THE START OF THE PERIOD.
TEMPERATURES ALOFT (850MB VALUES AROUND 1-2C) WILL BE FAVORABLE FOR
AT LEAST LAKE CLOUDS FRIDAY NIGHT INTO SATURDAY...BUT THE MAIN
CONCERN IS FOR THE AMOUNT OF LOW LEVEL MOISTURE AVAILABLE TO PRODUCE
CLOUDS. THE NAM CONTINUES TO SHOW ABUNDANT LOW LEVEL MOISTURE AND
HOLDS ON TO LAKE EFFECT CLOUDS FOR THE FAVORED NORTHERLY WIND
UPSLOPE LOCATIONS ON FRIDAY NIGHT AND THEN EXPANDS IT ACROSS THE
REST OF THE U.P. WITH DIURNAL HEATING ON SATURDAY. THE OTHER MODELS
ARE NOT AS EXCITED ABOUT THE LOW LEVEL MOISTURE WITH THE SURFACE
RIDGE MOVING INTO THE AREA. AT THIS POINT...WILL GO WITH PARTLY
CLOUDY SKIES FOR FRIDAY NIGHT (ESPECIALLY IN THE NORTHERLY UPSLOPE
AREAS) AND GRADUALLY DIMINISH THROUGH THE DAY ON SATURDAY.
UNFORTUNATELY...THAT DOES CREATE SOME QUESTION MARKS ON LOWS FOR
FRIDAY NIGHT AND IN TURN FROST POTENTIAL. THINK THERE WILL BE
ENOUGH GAPS IN THE CLOUDS OVER THE INTERIOR WEST THIRD OF THE U.P.
TO HAVE DECENT RADIATIONAL COOLING WITH THE DECOUPLING WINDS AND
HAVE CONTINUED TO SHOW LOWS IN THE MID 30S AND PATCHY FROST THERE.
THE HIGH PRESSURE RIDGE WILL MOVE OVER THE AREA SATURDAY
AFTERNOON/EVENING AND BRING CLEAR SKIES TO THE AREA. WITH THE CLEAR
SKIES AND LIGHT WINDS...EXPECT MUCH OF THE INTERIOR U.P. TO SEE
LOWS FALLING INTO THE 30S. WILL SHOW A LITTLE MORE COVERAGE OF THE
PATCHY FROST OVER THE WEST/CENTRAL AND INTO PARTS OF THE
EAST...ALTHOUGH THE WEST WILL LIKELY SEE RETURN FLOW DEVELOPING
DURING THE OVERNIGHT HOURS AND RAISE TEMPERATURES SLIGHTLY TOWARDS
MORNING.
SOUTHWESTERLY FLOW WILL CONTINUE SUNDAY AND THROUGH MUCH OF NEXT
WEEK AS A LOW MOVES THROUGH CENTRAL CANADA ON SUNDAY AND THEN
ANOTHER LOW TAKES SHAPE UNDER THE DEVELOPING UPPER TROUGH OVER THE
NORTHWESTERN CONUS EARLY NEXT WEEK. THE FIRST LOW WILL TRY TO DRAG
A COLD FRONT TOWARDS THE AREA ON MONDAY...BUT THE LATEST TRENDS
HAVE IT STALLING OVER MINNESOTA AND THEN LIFTING NORTH INTO ONTARIO
ON TUESDAY AS THE NEXT LOW DEVELOPS. THAT LOW WILL LIFT FROM
EASTERN MONTANA EARLY TUESDAY MORNING TO JAMES BAY BY WEDNESDAY
EVENING. THE WAY IT LOOKS NOW...THE U.P. WILL BE IN THE WARM SECTOR
FOR MOST OF THAT TIME FRAME AND EXPECT LITTLE TO NO PRECIPITATION
TO OCCUR. THUS...HAVE TRENDED POPS DOWN FOR TUESDAY...BUT DID BRING
IN SOME SLIGHT/CHANCE POPS TO THE WESTERN CWA FOR WEDNESDAY AS THE
COLD FRONT ASSOCIATED WITH THE SECOND LOW NEARS THE AREA. EXPECT
THAT COLD FRONT TO MOVE THROUGH ON WEDNESDAY NIGHT AND HAVE
INCREASED POPS TO HIGHER CHANCES. THE BREEZY SOUTHERLY WINDS FOR
MONDAY AND TUESDAY WILL WARM HIGHS TO ABOVE NORMAL VALUES AND
EXPECT HIGHS ON TUESDAY TO BE IN THE MID-UPPER 70S. EXPECT A SLIGHT
COOL DOWN BEHIND THE FRONT FOR THE END OF THE WORK WEEK...BUT
HIGHS WILL ONLY FALL TOWARDS MORE NORMAL VALUES FOR THIS TIME OF
YEAR (UPPER 60S TO AROUND 70).
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 216 PM EDT THU SEP 10 2015
VFR CONDITIONS WILL PREVAIL THRU AT LEAST THE EARLY EVENING HRS AT
KIWD/KCMX/KSAW. INCREASINGLY COLDER AIR...AN INCREASE IN LOW-LOW
LEVEL MOISTURE AND UPSLOPE FLOW SHOULD RESULT IN MVFR CIGS
DEVELOPING AT ALL TERMINALS OVERNIGHT. LIGHT LAKE EFFECT SHRA ARE
ALSO POSSIBLE...THOUGH IT APPEARS THE BETTER CHANCE WILL BE ON
FRIDAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT THU SEP 10 2015
PASSING COLD FRONT THIS MORNING FOLLOWED BY INCREASINGLY COLDER AIR
FLOWING INTO THE UPPER GREAT LAKES WILL RESULT IN INCREASING WINDS
ON LAKE SUPERIOR TODAY AND TONIGHT. WINDS SHOULD BE MOSTLY UNDER
20KT THRU THE MORNING BEFORE GUSTS RAMP UP AND REACH 20-30KT
TONIGHT. STRONGEST WINDS SHOULD BE ACROSS CNTRL LAKE SUPERIOR. WHILE
WINDS WILL SLOWLY DIMINISH OVER THE WRN LAKE ON FRI...20-30KT WINDS
WILL CONTINUE OVER THE E. HIGH PRES RIDGE ARRIVES SAT...RESULTING IN
WINDS FALLING OFF TO UNDER 15KT. INCREASING S TO SW WINDS ARE
EXPECTED SUN INTO MON AS HIGH PRES RIDGE DEPARTS AND A LOW PRES TROF
APPROACHES FROM THE NW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...JLA
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
219 PM EDT THU SEP 10 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT THU SEP 10 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A TROF EXTENDING S INTO
THE NCNTRL STATES AND UPPER GREAT LAKES...ANCHORED BY A MID LEVEL
LOW OVER NRN ONTARIO. SHORTWAVE MOVING ACROSS NRN ONTARIO IS HELPING
TO DRIVE A COLD FRONT SE...CURRENTLY ACROSS WRN LAKE SUPERIOR. DEEP
LAYER FORCING PER QVECTORS IS SUPPORTING AN AREA OF SHRA MOVING
ACROSS NE WI INTO SCNTRL UPPER MI EARLY THIS MORNING. ISOLD SHRA
HAVE BEEN OCCURRING FARTHER N TO LAKE SUPERIOR. EVEN A TSTM WAS
NOTED OVER ERN LAKE SUPERIOR A FEW HRS AGO.
AS FORCING SUPPORTING THE NE WI PCPN SHIFTS E...THIS MORE ORGANIZED
SHRA AREA WILL MOVE ACROSS THE SCNTRL AND PORTIONS OF THE ERN FCST
AREA OVER THE NEXT FEW HRS. THIS MAIN AREA OF PCPN SHOULD BE E OF
THE AREA NO LATER THAN MID MORNING. WITH COLD FRONT STILL PUSHING
SE...POTENTIAL IS THERE FOR ADDITIONAL ISOLD TO SCT SHRA DEVELOPMENT
UNTIL FROPA. THIS POTENTIAL SHOULD INCREASE DURING THE AFTN AS SOME
INSTABILITY BUILDS UP AHEAD OF COLD FRONT. DEVELOPING LAKE BREEZE
OFF LAKE MICHIGAN WILL ALSO STRENGTHEN THE LOW-LEVEL CONVERGENCE
ALONG THE SE MOVING COLD FRONT. RAP AND GFS SHOW MLCAPES UPWARDS OF
200-300J/KG OVER THE SCNTRL/SE FCST AREA. 00Z NAM SHOWED MLCAPE OVER
1000J/KG. WHILE THE 06Z NAM HAS PULLED BACK TO 600-800J/KG...IT
STILL LOOKS OVERDONE. IN ANY EVENT...THE AVBL INSTABILITY SUGGESTS
THE POTENTIAL FOR ISOLD TSTMS OVER THE SCNTRL/SE FCST AREA THIS AFTN
ALONG/AHEAD OF COLD FRONT.
CAA TODAY/TONIGHT WILL DROP 850MB TEMPS DOWN TO 0 TO 2C OVER LAKE
SUPERIOR BY 12Z FRI...SUFFICIENT FOR LAKE EFFECT PROCESSES WITH
WATER TEMPS ROUGHLY 15-18C. WITH NAM/GFS FCST SOUNDINGS SHOWING A
WELL MIXED LAYER IN LOWER 2KFT OF THE AIR MASS...BELIEVE IT WILL
TAKE SOME TIME TO GET LAKE EFFECT GOING TONIGHT...ESPECIALLY IN
LIGHT OF THE LACK OF SYNOPTIC SUPPORT WITH DEEP LAYER QVECTOR
DIVERGENCE DOMINATING. NOT EXPECTING ANYTHING MORE THAN ISOLD TO
PERHAPS SCT -SHRA COVERAGE. WITH WATER TEMPS MORE IN THE 12-15C
RANGE OVER THE ERN LAKE...-SHRA COVERAGE WILL BE LEAST OVER THE ERN
FCST AREA. IN FACT...THERE MAY NOT BE ANY LAKE EFFECT -SHRA OVER THE
FAR E TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 316 AM EDT THU SEP 10 2015
UPPER PATTERN CONSISTS OF A 500 MB RIDGE OVER THE WESTERN U.S. WITH
A TROUGH OVER THE UPPER GREAT LAKES 12Z FRI WITH A DEEP TROUGH OVER
THE EAST HALF OF THE U.S. THE TROUGH AXIS IS OVER THE CWA 12Z FRI
AND SLOWLY MOVES TO THE EAST BY 00Z SAT. THE TROUGH CONTINUES TO DIG
SOUTHEAST WITH A DEEP TROUGH OVER THE ERN U.S. ON SAT.
WITH THE TROUGH AXIS MOVING ACROSS THE AREA ON FRI...STILL NEED TO
KEEP SOME POPS IN THE FORECAST ESPECIALLY FOR DIURNALLY DRIVEN
SHOWERS. ALSO IS COLD ENOUGH FOR LAKE EFFECT CONTRIBUTION AS WELL AS
LAKE SUPERIOR TEMPERATURES RANGE FROM 10C TO 15C AND 850 MB RANGE
FROM 0C TO 2C ON FRIDAY AND THAT IS ENOUGH LAKE-850 MB DELTA-T TO
DEFINITELY HAVE SOME LAKE CONTRIBUTION TO THE PCPN AS WELL. WITH
LOSS OF DIURNAL HEATING FRI NIGHT...DRY THINGS OUT AND KEEP THAT WAY
THROUGH SAT NIGHT. DID NOT MAKE TOO MANY CHANGES TO THE GOING
TEMPERATURES AS THEY LOOKED FINE. KEPT IN SOME PATCHY FROST FOR FRI
NIGHT AND SAT NIGHT IN THE INTERIOR WEST AS LOWS FALL TO THE MID 30S.
IN THE EXTENDED...GFS AND ECMWF SHOW A CLOSED 500 MB LOW OVER THE
LOWER GREAT LAKES 12Z SUN WITH A RIDGE OVER THE DESERT SW. SFC FRONT
ON IS PARALLEL WITH UPPER FLOW ON SUNDAY ACROSS SOUTH CENTRAL
CANADA. A BROAD 500 MB TROUGH OVER THE NORTHERN ROCKIES 12Z MON WILL
DIGS SOUTHEAST 12Z TUE WITH A SFC FRONT BECOMING STATIONARY OVER THE
AREA ON TUE. AS A RIDGE BUILDS INTO THE EASTERN U.S. ON WED...THIS
FRONT WILL HEAD BACK NORTH AS A WARM FRONT ON WED. WILL BE A WARMING
TREND STARTING ON MON WITH TEMPERATURES GOING ABOVE NORMAL. HAVE
SOME SLIGHT CHANCE POPS IN FOR TUE AND TUE NIGHT WITH THE FRONT NEAR
THE AREA AND CHANCE POPS ON WED AS THE FRONT MOVES NORTH AS A WARM
FRONT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 216 PM EDT THU SEP 10 2015
VFR CONDITIONS WILL PREVAIL THRU AT LEAST THE EARLY EVENING HRS AT
KIWD/KCMX/KSAW. INCREASINGLY COLDER AIR...AN INCREASE IN LOW-LOW
LEVEL MOISTURE AND UPSLOPE FLOW SHOULD RESULT IN MVFR CIGS
DEVELOPING AT ALL TERMINALS OVERNIGHT. LIGHT LAKE EFFECT SHRA ARE
ALSO POSSIBLE...THOUGH IT APPEARS THE BETTER CHANCE WILL BE ON
FRIDAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT THU SEP 10 2015
PASSING COLD FRONT THIS MORNING FOLLOWED BY INCREASINGLY COLDER AIR
FLOWING INTO THE UPPER GREAT LAKES WILL RESULT IN INCREASING WINDS
ON LAKE SUPERIOR TODAY AND TONIGHT. WINDS SHOULD BE MOSTLY UNDER
20KT THRU THE MORNING BEFORE GUSTS RAMP UP AND REACH 20-30KT
TONIGHT. STRONGEST WINDS SHOULD BE ACROSS CNTRL LAKE SUPERIOR. WHILE
WINDS WILL SLOWLY DIMINISH OVER THE WRN LAKE ON FRI...20-30KT WINDS
WILL CONTINUE OVER THE E. HIGH PRES RIDGE ARRIVES SAT...RESULTING IN
WINDS FALLING OFF TO UNDER 15KT. INCREASING S TO SW WINDS ARE
EXPECTED SUN INTO MON AS HIGH PRES RIDGE DEPARTS AND A LOW PRES TROF
APPROACHES FROM THE NW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...07
AVIATION...JLA
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
140 PM EDT THU SEP 10 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 325 AM EDT THU SEP 10 2015
A TASTE OF EARLY FALL WILL COME SOUTHWEST MICHIGAN AS A POLAR COLD
FRONT MOVES ACROSS THE AREA LATER THIS AFTERNOON INTO EARLY
TONIGHT. THIS WILL BRING THE COOLEST AIR THIS AREA HAS SEEN SINCE
EARLY JUNG. SCATTERED SHOWERS WILL OVERSPREAD THE AREA FROM
NORTHWEST TO SOUTHEAST THIS AFTERNOON INTO THIS EVENING AS THE
COLD FRONT CROSSES THE AREA. FOR FRIDAY AND SATURDAY EXPECT
CONSIDERABLE CLOUD COVER...HIGHS ONLY FROM AROUND 60 TO THE MID
60S AND SCATTERED LAKE EFFECT SHOWERS. THE SHOWERS WILL BE
NUMEROUS NEAR THE LAKE MICHIGAN SHORE. SUNDAY INTO MONDAY THE COLD
AIR STARTS TO PULL AWAY FROM THE AREA SO SKIES WILL CLEAR AND
TEMPERATURES WILL SLOWLY WARM EACH DAY.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM EDT THU SEP 10 2015
OUR PRIMARY ISSUES ARE THE THREAT OF CONVECTION WITH THE COLD
FRONT THIS AFTERNOON INTO THIS EVENING...THEN WE WILL FOCUS ON THE
POTENTIAL FOR NORTH WIND LAKE EFFECT RAIN SHOWERS FOR THE FIRST
TIME THIS SEASON FOR FRIDAY INTO SATURDAY. BY SATURDAY MORNING THE
850 TEMPERATURE ANOMALIES AND THE 500 HEIGHTS WILL BE AROUND 4
STANDARD DEVIATIONS FROM NORMAL OVER THE LOWER GREAT LAKES INTO
THE OHIO VALLEY.
A 130 KNOT JET ROUNDING THE BASE OF THE TROUGH IN THE GULF OF
ALASKA EARLY THIS MORNING WILL INCREASE TO NEAR 145 KNOTS BY
TONIGHT AS IT HEADS TOWARD SOUTHERN ALASKA. THAT PUMPS UP THE
DOWNSTREAM RIDGE OVER WESTERN NORTH AMERICA...WHICH IN TURN DEEPS
THE DOWN STREAM TROUGH (OVER THE NORTHERN PLAINS). BY FRIDAY
AFTERNOON WE WILL HAVE A 110 KNOT JET CORE DIVING SOUTHWARD INTO
THE DEEPENING TROUGH OVER THE CENTRAL CANADA AND THE NORTHERN
PLAINS AND GREAT LAKES. THIS ACTION WILL LEAD TO A CLOSED UPPER
LOW BY SATURDAY MORNING OVER INDIANA AND WESTERN OHIO.
SO AS TYPICAL OF THIS SORT OF SET UP...THERE IS A BAND OF
CONVECTION HEAD OF THE COLD FRONT. MOISTURE TRANSPORT VECTORS IN
THE 1000/850 LAYER FOCUS THE BEST SHOWERS OVER NORTHERN LOWER
MICHIGAN THIS AFTERNOON AND EVENING. EVEN SO WITH PRECIPITABLE
WATER VALUES RISING TO AROUND 1.2 INCHES (ABOUT 150 PERCENT OF
NORMAL) THERE SHOULD BE ENOUGH MOISTURE FOR SOME SHOWERS THIS
AFTERNOON INTO THIS EVENING. THERE IS SOME MARGINAL INSTABILITY
BUT THE THE BEST CHANCE FOR THUNDERSTORMS WILL BE OVER NORTHWEST
SECTIONS LATE THIS AFTERNOON. AFTER THAT INSTABILITY IS TO FEEBLE
FOR THUNDERSTORMS.
ONCE IN THE COLD AIR WE SET UP FOR A NORTH WIND LAKE EFFECT EVENT
THAT COMMENCES ON FRIDAY AND LASTS INTO SATURDAY. ON FRIDAY
SOUNDING SUGGEST THERE IS ENOUGH INSTABLITLY FOR EQUILIBRIUM
LEVELS TO BE NEAR 20000 FT... MORE THAN ENOUGH FOR SHOWERS. ON
SATURDAY THE MOISTURE DEPTH IS LESS SO THE SHOWERS WILL MOSTLY BE
NEAR THE LAKE SHORE. ANOTHER ASPECT TO THIS THAT FAVORS SHOWERS IS
THAT LOWER MICHIGAN IS IN THE DEEP COLD AIR...INSIDE THE
CYCLONICLY CURVED JET AROUND THE OUTSIDE OF THE UPPER LOW. THE
BACK SIDE OF THAT JET DOES NOT CROSS SOUTHWEST MICHIGAN UNTIL
SUNDAY AFTERNOON. HAVING 850 MB TEMPERATURES FALL TO BETWEEN 2C
AND 4C..GIVEN THE 20C LAKE TEMPERATURES WILL BE MORE THAN COLD
ENOUGH FOR LAKE EFFECT SHOWERS TOO. ONCE AGAIN...WITH NORTH WINDS
THE SHOWERS WILL BE MOSTLY NEAR AND WEST OF US-31 FRIDAY AFTERNOON
INTO SATURDAY AFTERNOON.
INLAND SATURDAY MORNING SKIES MAY CLEAR SOMEWHAT SO WE COULD SEE
LOWS IN THE UPPER 30S IN THE NORMAL COOLER AREAS. I DO NOT THINK
FROST IS AN ISSUE YET. THAT WILL NOT BE TO FAR DOWN THE ROAD
THROUGH.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 325 AM EDT THU SEP 10 2015
A DRY PATTERN IS SETTING UP FOR MUCH OF THE LONG TERM. THE UPPER
TROUGH WILL BE MOVE EAST OUT OF THE CWA SATURDAY NIGHT AND AS SKIES
CLEAR TEMPS SHOULD FALL INTO THE LOWER TO MID 40S WITH SOME OF THE
COLDER SPOTS IN THE NORTHERN CWA REACHING THE UPPER 30S. AS THE SFC
RIDGE AXIS MOVES EAST BEGINNING SUNDAY WE/LL SEE TEMPS BEGIN TO
RISE. SUNDAY WILL STILL BE COOL WITH HIGHS IN THE MID 60S BUT HIGHS
WILL CLIMB INTO THE 70S BY MONDAY AND MAY APPROACH 80 BY MID WEEK.
RIDGING AT THE SFC AND ALOFT WILL MEAN DRY WX THROUGH TUESDAY NIGHT
AND MUCH OF WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 133 PM EDT THU SEP 10 2015
PATCHY MVFR CLOUDS EXIST WEST AND NORTH OF KMKG. LOOKS LIKE KMKG
COULD SEE A BRIEF PERIOD OF MVFR DUE TO THE INCREASING LOW LEVEL
MOISTURE. VFR WEATHER SHOULD PREVAIL THROUGH THE AFTERNOON AND
INTO THE EVENING AT THE REMAINDER OF THE TAF SITES IN SW LOWER
MI. A WAVE OF LOW PRESSURE TRACKS TOWARD SOUTHERN LOWER MI LATER
TONIGHT AND FRIDAY. THIS FEATURE WILL LIKELY SPREAD A BAND OF RAIN
INTO PARTS OF LOWER MI. THE INCREASING LOW LEVEL MOISTURE SHOULD
ALLOW FOR MVFR AND EVEN SOME IFR FOR SOUTHERN LOWER MI. THE LOWEST
CONDITIONS ARE FORECASTED FOR KAZO...KBTL AND KJXN.
THE RAIN PULLS AWAY FRIDAY AM. CONDITIONS WILL SLOWLY IMPROVE FROM
WEST TO EAST DURING THE DAY. LAKE EFFECT RAIN SHOWERS COULD
LOCALLY CAUSE IMPACTS ALONG THE LAKESHORE FRIDAY AFTERNOON.
&&
.MARINE...
ISSUED AT 929 AM EDT THU SEP 10 2015
WINDS AND WAVES HAVE INCREASED IN THE NEARSHORE ZONES FROM
PENTWATER TO MUSKEGON AS THE BAND OF SHOWERS AND ISOLATED
THUNDERSTORMS COMES ONSHORE. RAP AND WAVE MODELS SHOW THIS
INCREASE IN THE NEAR TERM...WITH CONDITIONS DIMINISHING THIS
AFTERNOON. WILL KEEP THE MARINE PRODUCTS HEADLINE FREE FOR
NOW...AND INSTEAD INCREASE THE WAVE HEIGHTS AND WINDS SLIGHTLY.
&&
.HYDROLOGY...
ISSUED AT 1116 AM EDT WED SEP 9 2015
CONCERNS FOR FLOODING IN THE FORECAST AREA HAVE DRASTICALLY
DECREASED SINCE YESTERDAY AND REMAIN FAIRLY LOW THROUGH THE NEXT
SEVERAL DAYS.
24 TO 48 HOUR RAINFALL TOTALS THIS MORNING REFLECT THAT 2.00+ INCH
AMOUNTS WERE RELATIVELY HARD TO COME BY. AMOUNTS OF 1-2 INCHES
FELL IN A SWATH FROM MUSKEGON TO LUDINGTON AND EASTWARD TO MOUNT
PLEASANT AND HARRISON. A MAJORITY OF LOCATIONS TO THE SOUTH LANDED
IN THE TERRITORY OF ONE-QUARTER TO THREE-QUARTERS OF AN INCH WITH
EXCEPTION TO THOSE AFFECTED BY LOCALIZED HEAVY RAINFALL.
AREA RIVERS HAVE SHOWN UPWARD MOVEMENT...ESPECIALLY IN PLACES THAT
EXCEEDED 1.50 INCHES OF RAINFALL. FORTUNATELY...WE DODGED A
BULLET IN THE SENSE THAT NO REPORTS OF 3.00+ INCHES WERE RECEIVED IN
THE LAST 24 HOURS. THOSE WHO RECEIVED HEAVIER RAINFALL TWO DAYS
AGO...PARTICULARLY INGHAM COUNTY...WERE SPARED OF HEAVIER RAINFALL
YESTERDAY. OVERALL...THE NEXT 36 HOURS OF DRY WEATHER WILL BODE
WELL FOR STREAMS AND RIVERS TO STABILIZE AND BEGIN TRENDING
DOWNWARD. RAINFALL IS EXPECTED LATE THURSDAY INTO FRIDAY WITH
OVERALL AMOUNTS REMAINING AROUND OR LESS THAN ONE-HALF AN INCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...MJS
HYDROLOGY...JAM
MARINE...MWS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
133 PM EDT THU SEP 10 2015
.UPDATE...
ISSUED AT 1105 AM EDT THU SEP 10 2015
UPSTREAM COLD FRONT CURRENTLY EXTENDS FROM CENTRAL UPPER MICHIGAN
THRU WISCONSIN INTO FAR ERN IOWA. THICK LINE OF SHOWERS CONTINUES
TO SLOWLY MOVE EASTWARD THRU OUR CWA LATE THIS MORNING. SOME
HIGHER REFLECTIVITIES...WHICH MAY HAVE RESULTED IN A FEW HITS OF
LIGHTNING...WERE NOTED AN HOUR OR SO AGO OVER LAKE MICHIGAN...BUT
HAVE SINCE DIMINISHED IN INTENSITY. NAM12...RAP13 AND HRRR ALL
SHOW VERY WEAK INSTABILITY DEVELOPING THIS AFTERNOON/EVENING
ACROSS OUR CWA...WITH CAPES ONLY INCREASING TO 500 JOULES OR LESS.
SOME WEAK COOLING ALOFT COMBINED WITH LIMITED LOW LEVEL DIURNAL
HEATING WILL LEND TO MINOR DESTABILIZATION THIS AFTERNOON...WHICH
MAY LEAD TO A FEW ADDITIONAL HITS OF LIGHTNING. HAVE ADDED A
SLIGHT CHANCE OF THUNDER TO ENTIRE CWA THIS MORNING...AND
CONTINUED THIS THRU THE AFTERNOON AS WELL. HAVE ALSO INCREASED
POPS IN MOST LOCATIONS...AND MAY NEED TO FURTHER INCREASE POPS IN
OUR ERN CWA IF THIS AREA OF SHOWERS CONTINUES TO HOLD TOGETHER.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 353 AM EDT THU SEP 10 2015
...A FEW SHOWERS AND POSSIBLY A THUNDERSTORM OR TWO TODAY...
SLOWLY FALLING HEIGHTS THROUGH THE PERIOD AS UPPER LEVEL TROUGHING
CENTERED ACROSS CENTRAL CANADA DIGS INTO THE GREAT LAKES. SHORT
WAVES MOVING THROUGH THE FLOW IN COMBINATION WITH CONVERGENCE ALONG
A SURFACE COLD FRONT WILL LEAD TO INCREASING SHOWER CHANCES TODAY
(FIRST ACROSS NORTHWEST ZONES THIS MORNING THEN FOR MUCH OF THE
REGION THIS AFTERNOON). IN ADDITION...A BIT OF INSTABILITY
(SEVERAL HUNDRED J/KG OF 0-1 KM MIXED LAYER CAPE) WILL LEAD TO
SLIGHT CHANCES FOR THUNDER THIS AFTERNOON. AS THE COOLER AIR
DEEPENS TONIGHT THE CHANCES FOR LAKE EFFECT RAIN SHOWERS INCREASE
AS 850 MB TEMPS DROP TO BETWEEN PLUS 3 AND PLUS 5 C. HIGHS TODAY
NEAR AVERAGE FOR THE DATE...UPPER 60S AND LOWER 70S. COOLER
TONIGHT THAN ANY TIME RECENTLY WITH LOWS IN THE MIDDLE 40S TO
MIDDLE 50S.
&&
.SHORT TERM...(FRIDAY THROUGH SATURDAY NIGHT)
ISSUED AT 353 AM EDT THU SEP 10 2015
HIGH IMPACT WEATHER: WATERSPOUT POTENTIAL ON FRIDAY NIGHT AND
SATURDAY.
FORECAST CHALLENGE: LAKE EFFECT RAIN POTENTIAL, AND WATERSPOUT
POTENTIAL FOR FRIDAY AND SATURDAY.
(9/11)FRIDAY...THE MAIN FRONT IS SOUTH OF THE FORECAST AREA, AND THE
COLD AIR ADVECTION IS REALLY PRESSING IN BY 12Z. IN FACT, THE GFS
HAS BECOME MUCH MORE AGGRESSIVE WITH THE COLD AIR AS IT HAS +2C IN N
LAKE MICHIGAN, WHILE THE ECMWF IS AROUND 4C. WINDS IN THE 1000-850
MB LAYER ARE OUT OF THE NNW MOST OF THE DAY, WITH THE MOISTURE IN
THE 850-700 MB LAYER AROUND 70% MOST OF THE DAY AS WELL. (REMEMBER
THE WATER TEMPERATURES ARE STILL AROUND 20C IN N LAKE MICHIGAN.
STILL A LITTLE CONCERNED IN E LAKE SUPERIOR WITH 15-20C WATER, BUT
IT LOOKS LIKE THE 850 MB TEMPERATURES ONLY FLIRT WITH 0C, WHICH
WOULD CAUSE MORE INSTABILITY AND RAIN SHOWERS FOR BETTER LAKE EFFECT
RAIN THERE, BUT AS IT STANDS, THERE WILL BE MARGINAL INSTABILITY IN
E UPPER AS THE WINDS CONTINUE TO VEER NORTH THROUGH THE NIGHT. SO
THIS LOOKS TO AFFECT THE REGION FROM AROUND TVC TO AND WEST ALONG
THE LAKE MICHIGAN SHORELINE TO MBL. SOUNDINGS DURING THE DAY AND
INTO THE NIGHT, DON`T LOOK THAT GREAT AS THE SOUNDINGS LOOK A LITTLE
DRY, TO ME. SO HAVE KEPT THE POPS TO HIGH CHANCE OVER N FLOW
REGIONS. OF COURSE WITH THE TALK OF LAKE EFFECT RAIN, THE CHANCE FOR
WATER SPOUTS IS HIGHER, WITH THE 500 MB CUT OFF LOW ROTATING OVER
THE REGION AND EQUILIBRIUM LEVELS OF AROUND 10K FEET IF MODIFYING TO
THE LOWER PART OF THE SOUNDINGS TO THE WATER TEMPERATURES.
(9/12)SATURDAY...IT LOOKS LIKE THAT THE BEGINNING OF THE DAY SHOULD
CONTINUE THE CHANCE FOR LE RAIN SHOWERS IN THE WEST, WITH THE CHANCE
FOR WATERSPOUTS AS WELL, BUT THE LATER WE GET INTO THE DAY, THE
SOUNDINGS BEGIN TO DRY OUT SO THAT BY 00Z, THE SKIES SHOULD BEGIN TO
CLEAR OUT ALONG THE LAKE MICHIGAN SHORELINE. ESPECIALLY AS THE 850
MB TEMPERATURES WARM WITH THE SFC HIGH BUILDING INTO THE REGION, AND
THE 500 MB LOW MOVING OFF TO THE EAST.
&&
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 353 AM EDT THU SEP 10 2015
WITH THE 500 MB LOW MOVING TO
THE EAST, THE PATTERN BECOMES QUITE AMPLIFIED AS 500 MB RIDGING
DOMINATES THE UPPER GREAT LAKES THROUGH TUESDAY NIGHT. THEN
WEDNESDAY, AND IT LOOKS LIKE LATE IN THE DAY, THE RIDGE BEGINS TO
BREAK DOWN WITH THE ANOTHER COLD FRONT WITH THE CHANCE FOR RAIN TO
MOVES INTO THE REGION OVERNIGHT WEDNESDAY AND INTO THURSDAY.
TEMPERATURES LOOK TO BE ABOVE NORMAL FOR A DAY OR TWO BEFORE COMING
BACK DOWN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 133 PM EDT THU SEP 10 2015
A COLD FRONT WILL SWING THRU MICHIGAN THIS AFTERNOON AND
TONIGHT...PRODUCING SCATTERED SHOWERS. AN ISOLD THUNDERSTORM IS
ALSO POSSIBLE...BUT CHANCES ARE TOO LOW TO INCLUDE IN THE TAF
FORECAST. OVERALL CONDITIONS WILL REMAIN LOW VFR/HIGH MVFR THRU
FRIDAY AFTERNOON AS THIS FRONT SWINGS THRU. CAA IN THE WAKE OF THE
FRONT WILL DROP TEMPS LATER TONIGHT INTO FRIDAY AND WILL PRODUCE
SCATTERED LAKE ENHANCED RAIN SHOWERS...ESPECIALLY ACROSS NW LWR
MICHIGAN (PLN/TVC/MBL).
&&
.MARINE...
ISSUED AT 353 AM EDT THU SEP 10 2015
WINDS WILL BE SOUTHWEST TODAY THEN A COLD FRONT PASSES...SHIFTING
WINDS INTO THE NORTH TONIGHT. COLDER AIR AND AN UPPER LEVEL TROUGH
OVER THE GREAT LAKES REGION WILL RESULT IN WATERSPOUTS BECOMING A
GREATER THREAT...ESPECIALLY FRIDAY NIGHT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...MLR
NEAR TERM...SULLIVAN
SHORT TERM...JSL
LONG TERM...JSL
AVIATION...MLR
MARINE...SULLIVAN
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
341 PM CDT THU SEP 10 2015
.SHORT TERM: (Through Late Tonight)
Issued at 338 PM CDT Thu Sep 10 2015
Spotty convection will continue across most of the FA early
this evening due to numerous outflow/surface boundaries migrating
through mostly unstable airmass of MLCAPES 1000-2000 j/kg. However,
still believe the primary "show" will be late this evening and
overnight as primary shortwave energy digs into the region and
begins to interact with southward sagging cold front/baroclinic
zone. Last several runs of the HRRR continue to support idea that
convection over NE will drop/develop across e KS and w MO during the
early evening hours as UVV increases due to shortwave as well as
increasing isentropic ascent, with the resultant elevated shower
and embedded thunderstorm threat overspreading much of the CWA
during the overnight hours. Have highest PoPs (~80%) over mid MO
where lift and moisture advection should be maximized...this is a
bit higher/bit further north than earlier forecast, but models are
still indicating good divergence developing across northern MO in
the RRQ of the back building upper level jet. PoPs then taper off
to high chance over far northern and southern sections of the FA as
precip should tend to "fade" a bit as it advects out of the primary
zone of ascent.
Truett
.LONG TERM: (Friday through Next Thursday)
Issued at 338 PM CDT Thu Sep 10 2015
Even though frontal boundary will be south of forecast area by 12z
Friday, will see some lingering post frontal precipitation gradually
tapering off from north to south, including some isolated
thunderstorms. Otherwise, colder air to filter into the region and
with plenty of cloud cover and rain, temperatures will only rise
into the upper 60s to mid 70s.
Dry and colder weather to prevail through the weekend. Could see a
stray shower on Saturday as decent shortwave energy rotates around
upper level trof that is anchored over the Great Lakes. For now have
dry conditions, but will need to keep an eye on the models as we get
closer to this time period.
By Sunday night surface ridge will begin to move off to the
southeast. This will allow southerly winds to return once again and
temperatures moderate back into the 80s by Tuesday.
Extended models hinting at another cold front moving through region
beginning Wednesday night. Have low chance pops Wednesday night and
Thursday.
Byrd
&&
.AVIATION: (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1255 PM CDT Thu Sep 10 2015
SCT to occasionally BKN CU field with bases aoa 4kft expected
across the FA this afternoon. There appears to be two areas of
potential convection for this afternoon...one is associated with
weak convergence along cold front/surface trof that will be
drifting into the KUIN area this afternoon, and have maintained
VCTS for several hours in KUIN TAF in the late afternoon and early
evening hours for this threat. Second area is isolated/AMS-type
convection forming ahead of shortwave now entering STL Metro. Have
maintained a dry forecast at all metro area TAFs for now, but
getting a few cells forming to the NW of the area, and if they
hold together/intensify may need to nowcast this threat into some
of the metro TAFS.
However, still believe the primary threat of convection during
this TAF period will be late this evening and overnight, as
discussed in Short-term AFD update. Like the trends suggested by
the 15z HRRR, and have trended onset of precip and potential
thunderstorm activity based on this output. Both NAM and GFS MOS
suggest cigs lowering to IFR in the primary rain area along and
I-70 corridor during the predawn hours...haven`t gone quite this
low, but given time of year and post-frontal cool air...low end
MVFR certainly seems reasonable.
Specifics for KSTL: Scattered CU with bases aoa 4kft expected this
afternoon. AMS-type storms will dot the area, but will isolated
coverage will monitor their trends and use nowcast techniques to
determine if these will impact TAF area. Much larger of area of
rain and embedded thunderstorms expected to work into the area
after 06z, with ceilings in the stratus and rain deteriorating to
low-end MVFR by daybreak Friday.
Truett
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1237 PM CDT THU SEP 10 2015
.MESOSCALE DISCUSSION...
Issued at 1150 AM CDT THU SEP 10 2015
Convection that faded as it moved into the Ozarks this morning
has left a few boundaries across the the region that can be seen
in the visible satellite imagery. The most notable were one along
the I-49 corridor across western Missouri and another that
stretched from southeastern Barry to central Dent Counties.
Instability across the western half of the Ozarks, generally west
of the highway 65 corridor was showing from 1400-1800 j/kg with
the best instability across eastern Kansas. There was little CINH
noted along I-49 and west into Southeastern Kansas. With this
combination of instability, low CINH and residual boundaries it
will be possible for storm development this afternoon with the
primary area of potential convection expected mainly along and
west of I-49.
Development may begin over the next few hours as noted on short
term mesoscale models. This development would likely diminish once
the sun goes down and daytime heating subsides, which would allow
the airmass to recharge ahead of the cold front that is expected
to move through the region during the overnight hours.
&&
.UPDATE...
Issued at 0540 AM CDT THU SEP 10 2015
A small convective complex near Kansas City has thus far refused
to die this morning, despite the loss of nearly all of its low
level jet support. With the HRRR now suggesting that this complex
may well hold together into southern Missouri, have gone ahead and
added PoPs along it`s expected path, which for now is from roughly
Clinton to Springfield. Trends will be monitored with additional
adjustments to PoPs likely over the next few hours.
&&
.SHORT TERM...(Today and Tonight)
Issued at 0240 AM CDT THU SEP 10 2015
This morning is starting out rather mild across the region, with
temperatures at 2 AM generally in the mid to upper 60s. Despite
ample low level moisture and T/Td spreads of only a degree or two,
fog has been slow to form so far, likely due to the presence of
very light southerly winds, and the approach of scattered cirrus
from the northwest. That said, I do think there is still the
potential for fog to form through sunrise, though it may not end
up being quite as widespread as initially thought.
Light south to southwest winds and high cloud cover can be
expected today, with temperatures warming into the low to mid 80s
by this afternoon.
A cold front currently located across the Great Lakes and northern
Plains will sharpen and accelerate south this evening into
tonight, and pass through the forecast area from north to south
during the overnight hours into Friday morning. Initial convection
near the KC area late this afternoon may be strong to severe, and
we will need to watch for the potential for a few of the stronger
storms to move into the northwestern corner of the CWA tonight.
For most of the forecast area, however, it appears that
instability will be low enough to preclude widespread severe
weather with this system. Gusty 40-50 MPH winds will still be
possible late tonight as convection moves through the area,
however.
.LONG TERM...(Friday through Wednesday)
Issued at 0240 AM CDT THU SEP 10 2015
The front should clear the area by mid day Friday, with a much
cooler and drier airmass quickly building into the area. A few
lingering showers/storms will be possible over far southern/south
central Missouri early Friday, but dry weather is expected for
most. Right now, it appears that highs on Friday may only reach
the low to perhaps mid 70s, with dewpoints quickly falling into
the low 50s by afternoon.
Even cooler conditions are then expected Friday night through
Sunday, with low temperatures around 50 Saturday morning, and
Sunday morning lows dropping into the 40s for most! Highs on
Saturday and Sunday will be in the upper 60s to around 70
degrees, some 10-15 degrees below average.
Expansive high pressure will continue to build across the
Southeastern U.S. through the early part of next workweek. This
will eventually result in southerly return flow across the Ozarks
by Tuesday and Wednesday, with temperatures (and dewpoints)
increasing back to or above normal values. The increase in
temperatures and humidity should result in a corresponding
increase in thunderstorm potential by the middle of next week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1234 PM CDT THU SEP 10 2015
Aviators flying into the Ozarks over the next 24 hour will need
to monitor for isolated to scattered afternoon convection
developing across the region this afternoon through sunset.
several boundaries may allow storms to focus over portions of the
region that will affect the regions aerodromes. Storms that
develop this afternoon will remain scattered in nature. The
primary concern will come during the overnight hours as a cold
front moves through the region. winds will shift from southerly
to northwesterly as the front passes. During the frontal passage
and behind it, ceilings will fall from MVFR to IFR with
visibilities variable from VFR to IFR with rainfall and frontal
passage.
The front should be through most of the Ozarks by mid day Friday
with slowly improving flight conditions through the remainder of
the day.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
MESOSCALE...Hatch
UPDATE...Boxell
SHORT TERM...Boxell
LONG TERM...Boxell
AVIATION...Hatch
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1208 PM CDT THU SEP 10 2015
.MESOSCALE DISCUSSION...
Issued at 1150 AM CDT THU SEP 10 2015
Convection that faded as it moved into the Ozarks this morning
has left a few boundaries across the the region that can be seen
in the visible satellite imagery. The most notable were one along
the I-49 corridor across western Missouri and another that
stretched from southeastern Barry to central Dent Counties.
Intability across the western half of the Ozarks, generally west
of the highway 65 corridor was showing from 1400-1800 j/kg with
the best instability across eastern Kansas. There was little CINH
noted along I-49 and west into Southeastern Kansas. With this
combination of instability, low CINH and residual boundaries it
will be possible for storm development this afternoon with the
primary area of potential convection expected maily along and
west of I-49.
Development may begin over the next few hours as noted on short
term mesoscale models. This development would likely diminish once
the sun goes down and daytime heating subsides, which would allow
the airmass to recharge ahead of the cold front that is expected
to move through the region during the overnight hours.
&&
.UPDATE...
Issued at 0540 AM CDT THU SEP 10 2015
A small convective complex near Kansas City has thus far refused
to die this morning, despite the loss of nearly all of its low
level jet support. With the HRRR now suggesting that this complex
may well hold together into southern Missouri, have gone ahead and
added PoPs along it`s expected path, which for now is from roughly
Clinton to Springfield. Trends will be monitored with additional
adjustments to PoPs likely over the next few hours.
&&
.SHORT TERM...(Today and Tonight)
Issued at 0240 AM CDT THU SEP 10 2015
This morning is starting out rather mild across the region, with
temperatures at 2 AM generally in the mid to upper 60s. Despite
ample low level moisture and T/Td spreads of only a degree or two,
fog has been slow to form so far, likely due to the presence of
very light southerly winds, and the approach of scattered cirrus
from the northwest. That said, I do think there is still the
potential for fog to form through sunrise, though it may not end
up being quite as widespread as initially thought.
Light south to southwest winds and high cloud cover can be
expected today, with temperatures warming into the low to mid 80s
by this afternoon.
A cold front currently located across the Great Lakes and northern
Plains will sharpen and accelerate south this evening into
tonight, and pass through the forecast area from north to south
during the overnight hours into Friday morning. Initial convection
near the KC area late this afternoon may be strong to severe, and
we will need to watch for the potential for a few of the stronger
storms to move into the northwestern corner of the CWA tonight.
For most of the forecast area, however, it appears that
instability will be low enough to preclude widespread severe
weather with this system. Gusty 40-50 MPH winds will still be
possible late tonight as convection moves through the area,
however.
.LONG TERM...(Friday through Wednesday)
Issued at 0240 AM CDT THU SEP 10 2015
The front should clear the area by mid day Friday, with a much
cooler and drier airmass quickly building into the area. A few
lingering showers/storms will be possible over far southern/south
central Missouri early Friday, but dry weather is expected for
most. Right now, it appears that highs on Friday may only reach
the low to perhaps mid 70s, with dewpoints quickly falling into
the low 50s by afternoon.
Even cooler conditions are then expected Friday night through
Sunday, with low temperatures around 50 Saturday morning, and
Sunday morning lows dropping into the 40s for most! Highs on
Saturday and Sunday will be in the upper 60s to around 70
degrees, some 10-15 degrees below average.
Expansive high pressure will continue to build across the
Southeastern U.S. through the early part of next workweek. This
will eventually result in southerly return flow across the Ozarks
by Tuesday and Wednesday, with temperatures (and dewpoints)
increasing back to or above normal values. The increase in
temperatures and humidity should result in a corresponding
increase in thunderstorm potential by the middle of next week.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 0623 AM CDT THU SEP 10 2015
With a weakening cluster of storms dropping southeast from Kansas
City this morning, went ahead and included tempo group for storms
around mid morning at Springfield and Joplin. Otherwise, will
bring in another vicinity/tempo group for afternoon convective
potential with approaching front/shortwave trough. Expect a wind
shift from south to northwest should occur between 04z and 08z
as the front drops quickly south of the MO border.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
MESOSCALE...Hatch
UPDATE...Boxell
SHORT TERM...Boxell
LONG TERM...Boxell
AVIATION...Terry
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
324 PM CDT THU SEP 10 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 323 PM CDT THU SEP 10 2015
STRONG TO LOCALLY SEVERE THUNDERSTORMS ARE THE PRIMARY CONCERN GOING
IN THE NEAR TERM...WITH THE MAIN THREAT AREA FOR SEVERE WEATHER
MAINLY ACROSS OUR FAR SOUTHEASTERN ZONES. LARGE SCALE FORCING IN
ASSOCIATION WITH NORTHERN PLAINS IMPULSE HAS ALREADY SPARKED OFF
SHOWERS AND A FEW STRONG THUNDERSTORMS THIS AFTERNOON. DEVELOPMENT
HAVE BEEN NOTICED ACROSS OUR NORTHERN ZONES WHERE THE ATMOSPHERE IS
CHARACTERIZED AS WEAKLY UNSTABLE. A SECOND AREA OF DEVELOPMENT
APPEARS TO BE ALONG A MID-LEVEL FRONT ACROSS SOUTHEASTERN CUSTER
COUNTY WEST INTO THE SANDHILLS AND THE THIRD IS ACROSS FAR SOUTHWEST
NEBRASKA /EAST OF MCK/. THIS DEVELOPMENT IS FOCUSING ALONG A DRY
LINE.
WILL NEED TO MONITOR OUR SOUTHEASTERN ZONES AS THEY LIE IN A
FAVORABLE REGION FOR SUPERCELL DEVELOPMENT. MESOANALYSIS FROM
ACROSS OUR SOUTHEASTERN ZONES REVEALS AMPLE INSTABILITY...WITH
SBCAPES ESTIMATED AT 3500 J/KG WITH FAVORABLE INCREASING/VEERING
WINDS ALOFT ACROSS MUCH OF FRONTIER COUNTY. THE SPC SIGNIFICANT HAIL
PARAMETER INDICATES A BULLSEYE OF 3 ALONG THE LINCOLN/FRONTIER
COUNTY LINE AND A 2 OVER MUCH OF OUR SOUTHEASTERN ZONES. THE
SUPERCELL COMPOSITE GENERALLY FAVORS THE SAME AREA. LARGE HAIL IS
THE PRIMARY CONCERN WHERE STORMS FORM ACROSS OUR SOUTHEASTERN ZONES.
LATEST HRRR GUIDANCE IS PICKED UP ON THE SB CONVECTION ACROSS OUR
FAR SOUTHEASTERN ZONES WELL IN PREVIOUS RUNS...BUT LARGELY IGNORED
THE MID-LEVEL FRONT /ELEVATED CONVECTION OVER THE SANDHILLS EAST
THROUGH CUSTER COUNTY/ UNTIL THE MOST RECENT RUN. THE MODEL HAS
BEEN STEADY THOUGH SUGGESTING THE POTENTIAL SEVERE ACTIVITY
SOUTHEAST OF THE FORECAST AREA SHORTLY AFTER 22Z. FOR THE NORTHERN
SHOWERS AND WEAK STORMS...THE FORCING WILL QUICKLY SHIFT EAST THIS
EVENING...WITH THE SHOWERS EXPECTED TO BE OVER BY MID-EVENING.
POST FRONTAL CONDITIONS WILL PROVIDE FOR A DRY AND COOL DAY ACROSS
THE CENTRAL PLAINS ON FRIDAY. HIGHS ARE FORECAST TO WARM INTO THE
60S TO LOWER 70S ACROSS THE FORECAST AREA.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 323 PM CDT THU SEP 10 2015
FOR FRIDAY NIGHT AND SATURDAY...AN AMPLIFIED NWRLY FLOW ALOFT WITH
A RETURN OF SOUTHERLY WINDS WITH HIGHS WARMING TO THE LOWER 80S
ACROSS THE WEST WHILE THE EAST REMAINS IN THE LOWER TO MID 70S.
ON SUNDAY...A BROAD TROUGH WILL EXTEND WEST TO EAST ACROSS CANADA
WITH FAIRLY ZONAL FLOW ACROSS THE NRN CONUS. THIS WILL BRING A
THERMAL RIDGE EASTWARD INTO THE PLAINS AS H85 TEMPS IN WRN NEBR
REACH 25 TO 30C. HIGHS WERE NUDGED UPWARD TO NEAR 90 WEST.
FOR MONDAY THROUGH THURSDAY...ABOVE NORMAL TEMPERATURES. UPPER
FLOW WILL BECOME SOUTHWESTERLY ALOFT MONDAY AND TUESDAY AS AN
UPPER TROUGH DIGS INTO THE NWRN CONUS. THIS WILL ACT TO EXPAND
THE THERMAL RIDGE EASTWARD ACROSS THE CENTRAL PLAINS. HIGHS AGAIN
NUDGED UPWARD TO THE UPPER 8OS TO AROUND 90 MOST AREAS THESE HIGHS
WILL BE 10 TO 15 DEGREES ABOVE NORMAL.
A COLD FRONT TUESDAY NIGHT TO BRING A SLIGHT CHC FOR SHOWERS AND
THUNDERSTORMS. EXTENDED PROCEDURE KEEPS WEDNESDAY DRY EXCEPT A
SLIGHT CHANCE IN THE NORTHEASTERN AREAS. FUTURE MODEL RUNS MAY
SHOW BETTER SUPPORT FOR WEDNESDAY AND WEDNESDAY NIGHT. BEHIND THE
FRONT....HIGHS COOL BACK SOME TO THE UPPER 70S NORTH AND LOWER 80S
NORTH FOR WEDNESDAY AND THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1232 PM CDT THU SEP 10 2015
THE FORECAST CALLS FOR A SLIGHT CHANCE OF SHOWERS AND/OR
THUNDERSTORMS AT BOTH THE LBF AND VTN TERMINALS THROUGH THIS
EVENING...HOWEVER THE GREATEST OPPORTUNITY OF A STRONG OR SEVERE
STORM WILL LIE TO THE SOUTHEAST OF THE LBF TERMINAL. THE MOST
RECENT NEAR TERM CONVECTIVE ALLOWING MODEL RUN DOES GENERATE
STORMS AFTER 21Z THIS AFTERNOON SOUTH OF INTERSTATE 80 AND EAST OF
HIGHWAY 83...SO THE TRENDS WILL BE MONITORED CLOSELY FOR LBF. THE
ACTIVITY WILL SHIFT QUICKLY OFF TO THE SOUTHEAST...WITH ANY
POTENTIAL CONVECTION WELL SOUTHEAST OF THE TERMINAL BEFORE 00Z.
AT VTN...AN UPPER LEVEL DISTURBANCE MAY SPARK OFF A SHOWER THROUGH
THIS EVENING...BUT THE COVERAGE DOES NOT WARRANT A MENTION IN THE
TAF FOR NOW. OTHERWISE GUIDANCE INDICATES A RETURN OF LOWER
VISIBILITY AT LBF AFTER 09Z FRIDAY...BUT THIS WAS DISCOUNTED AS AN
OVERCAST DECK AOA 12K FT AGL IS ANTICIPATED.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JACOBS
LONG TERM...ROBERG
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
940 AM PDT THU SEP 10 2015
.SYNOPSIS...MONSOON MOISTURE WILL KEEP THUNDERSTORMS IN THE FORECAST
ACROSS THE MOJAVE DESERT SOUTH OF LAS VEGAS AGAIN TODAY. MAINLY
DRY AND HOT CONDITIONS ARE EXPECTED FRIDAY AS HIGH PRESSURE
STRENGTHENS OVERHEAD. CONFIDENCE CONTINUES TO INCREASE IN MOISTURE
ASSOCIATED WITH TROPICAL STORM LINDA TO PUSH NORTH ACROSS THE
REGION THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.UPDATE...SATELLITE LOOP SHOWED A LARGE AREA OF FAIRLY THICK CLOUD
COVER ACROSS MOST OF SAN BERNARDINO COUNTY INTO SOUTHERN MOHAVE
COUNTY. I UPDATED TO INCREASE SKY COVER ACCORDINGLY. I ALSO ADDED A
MENTION OF THUNDERSTORMS TO PORTIONS OF NORTHERN MOHAVE COUNTY AS
MODELS AND CURRENT MESOANALYSIS INDICATE SOME INSTABILITY AND THERE
SHOULD BE ENOUGH MOISTURE IN PLACE. -HARRISON-
&&
.PREV DISCUSSION...
346 AM PDT THU SEP 10 2015
.SHORT TERM...TODAY THROUGH SATURDAY MORNING.
CONVECTION FROM YESTERDAY AFTERNOON AND EVENING HAS DIMINISHED
ACROSS THE ENTIRE REGION. THE LATEST SATELLITE IMAGERY SHOWS MID-
LEVEL MOISTURE COURTESY OF TROPICAL STORM LINDA CONTINUING TO STREAM
FROM SOUTHWEST TO NORTHEAST ACROSS FAR SOUTHERN PORTIONS OF THE
FORECAST AREA. THIS WILL SET THE STAGE FOR ANOTHER DAY OF ISOLATED
TO SCATTERED THUNDERSTORMS ACROSS MAINLY MOHAVE AND SAN BERNARDINO
COUNTIES.
THE CLOUD SHIELD FROM LINDA WILL CONTINUE TO EASE NORTHWARD OVER THE
COURSE OF TODAY...WITH THE NORTHERN PERIPHERY OF THE CLOUD SHIELD
BEING A FAVORED REGION ALONG WITH TERRAIN FOR CONVECTIVE DEVELOPMENT
LATER THIS MORNING. THIS COINCIDES WITH THE FORECAST REGION OF BEST
INSTABILITY INDICATED ON THE LATEST RUNS OF THE NAM 12...WHICH WAS
THE BEST PERFORMING MODEL WITH INSTABILITY PARAMETERS YESTERDAY. THE
LATEST LOCAL HI-RES MODELS AND RUNS OF THE HRRR POINT TOWARD
CONVECTIVE INITIATION OCCURRING BETWEEN 18-19Z LATER TODAY ACROSS
CENTRAL AND SOUTHERN PORTIONS OF SAN BERNARDINO AND MOHAVE COUNTIES.
AT THIS TIME...IT APPEARS AS IF COVERAGE WILL BE SIMILAR TO WHAT WAS
OBSERVED YESTERDAY...WITH ACTIVITY AGAIN TAPERING OFF THIS EVENING
WITH THE LOSS OF DAYTIME HEATING. DRY MID-LEVEL AIR WILL AGAIN HELP
TO KEEP AREAS FROM ROUGHLY LAS VEGAS NORTHWARD EFFECTIVELY CAPPED
AGAIN TODAY.
THURSDAY NIGHT INTO FRIDAY...MID TO UPPER LEVEL DRY AIR WILL INTRUDE
THE AREA FROM THE NORTHEAST AS THE CENTER OF THE HIGH SHIFTS
WESTWARD. THIS WILL SCOUR OUT MOISTURE FROM NORTHEAST TO SOUTHWEST
AT MID AND UPPER LEVELS...CONFINING ANY CHANCES FOR THUNDERSTORMS TO
SOUTHWESTERN PORTIONS OF SAN BERNARDINO COUNTY. AFTERNOON HIGH
TEMPERATURES WILL CONTINUE TO RUN ROUGHLY 8-10 DEGREES ABOVE
SEASONAL NORMALS THROUGH SATURDAY AFTERNOON...BEFORE A PATTERN
CHANGE SPELLS A SHARP COOLDOWN AND AN INCREASE IN SHOWER AND
THUNDERSTORM ACTIVITY FROM SUNDAY ONWARD.
.LONG TERM...SUNDAY THROUGH WEDNESDAY.
CONFIDENCE IS INCREASING THAT ABUNDANT REMNANT MOISTURE FROM
DECAYING TROPICAL STORM LINDA WILL SPREAD OVER THE REGION SUNDAY AND
MONDAY. THE OPERATIONAL GFS AND ECMWF ARE NOW IN GENERALLY GOOD
AGREEMENT WITH THE EVOLVING PATTERN. THEY DEPICT THE REMNANT MID
LEVEL MOISTURE FROM LINDA BEING PULLED UP ALONG THE CALIFORNIA COAST
BY A CIRCULATION OVER THE EASTERN PACIFIC...CURRENTLY CENTERED NEAR
30N 135W. AS THIS CIRCULATION APPROACHES THE CENTRAL CALIFORNIA
COAST...IT APPEARS TO INFUSE THE WEAKENING MID LEVEL CIRCULATION
FROM LINDA AND KICK IT INLAND ACROSS SOUTHERN CALIFORNIA AND
SOUTHERN NEVADA SUNDAY. CONSIDERABLE CLOUD COVER AND LIGHT SHOWERS
WILL MOST LIKELY RESULT SUNDAY AS MODEL FORECAST SOUNDINGS INDICATE
ONLY MARGINAL INSTABILITY. SO...HEAVY RAIN PRODUCING THUNDERSTORMS
DO NOT APPEAR AS FAVORABLE AS THEY DO MONDAY...WHEN DEEPER MOISTURE
WILL BE IN PLACE. AN INCREASING SOUTHWEST JET IS FORECAST TO MOVE
OVER SOUTHERN CALIFORNIA AND SOUTHERN NEVADA MONDAY WHILE THE
CIRCULATION THAT MOVED INTO CENTRAL CALIFORNIA PHASES WITH A DEEP
LOW PRESSURE SYSTEM DROPPING INTO THE PACIFIC NORTHWEST. EASTERN SAN
BERNARDINO...CLARK...LINCOLN AND MOHAVE COUNTIES COULD SEE HEAVY
RAIN PRODUCING THUNDERSTORMS WITH SOME MORE ORGANIZED CELLS DUE TO
INCREASING WIND SHEAR. STORM MOTION WILL ALSO INCREASE WHICH WILL BE
A FACTOR WORKING AGAINST THE FLASH FLOOD THREAT. POP VALUES WERE
INCREASED 10-20 PERCENT SUNDAY THROUGH MONDAY DUE TO THE
A BROAD TROUGH IS FORECAST TO BE OVER THE WESTERN STATES TUESDAY AND
SOME DRYING SHOULD OCCUR DUE TO THE SOUTHWEST FLOW.
HOWEVER...LINCOLN AND MOHAVE COUNTIES MAY STILL SEE THE POTENTIAL
FOR SIGNIFICANT THUNDERSTORMS DUE TO LINGERING MOISTURE. WEDNESDAY
SHOULD SEE FURTHER DRYING FROM THE TROUGH WITH DECREASING STORM
COVERAGE. A DEFINITE COOLING TREND WILL OCCUR DUE TO THE
AFOREMENTIONED FACTORS WHICH WAS ALREADY INDICATED IN THE INHERITED
GRIDS. TEMPERATURES WERE DECREASED SLIGHTLY EACH DAY BASED ON THE
LATEST GUIDANCE.
&&
.AVIATION...FOR MCCARRAN...LIGHT WINDS GENERALLY UNDER 8 KTS ARE
EXPECTED TODAY...GENERALLY FROM AN EASTERLY DIRECTION DURING THE DAY
AND SOUTH-SOUTHWEST OVERNIGHT. SHRA/TSRA ARE POSSIBLE MAINLY TO THE
SOUTH OF THE TERMINAL TODAY...WITH A SLIGHT CHANCE OF TSRA
DEVELOPING IN THE MCCULLOUGH RANGE AND/OR SPRING MOUNTAINS LATER
THIS AFTERNOON.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SCATTERED-ISOLATED SHRA/TSRA WILL BE POSSIBLE AGAIN
THIS AFTERNOON PRIMARILY SOUTH OF KLAS. GUSTY AND ERRATIC WINDS WILL
BE POSSIBLE IN AND NEAR ANY SHRA/TSRA. OTHERWISE RELATIVELY LIGHT
WINDS WILL FAVOR TYPICAL DIURNAL TRENDS. EXPECT SCT-BKN CLOUDS AOA
7K-12K FEET AS WELL SOUTH OF LAS VEGAS. AREAS OF FU AND HZ ARE
POSSIBLE IN AROUND KBIH REDUCING VSBY AND CREATING LOCALIZED
MOUNTAIN OBSCURATIONS.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...PULLIN
LONG TERM.............ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
701 PM EDT THU SEP 10 2015
.SYNOPSIS...
HIGH PRESSURE REMAINS WELL OFF THE SOUTHEAST COAST THROUGH
FRIDAY. A WEAK TROF OF LOW PRESSURE WILL APPROACH FROM THE WEST
TONIGHT THEN SLOWLY MOVE INTO THE AREA ON FRIDAY. AREA OF LOW
PRESSURE WILL DEVELOP NORTHWEST OF THE REGION SATURDAY INTO
SATURDAY NIGHT THEN PASS NORTH OF THE AREA SUNDAY. A COLD FRONT
TRAILING THE LOW WILL CROSS THE AREA SUNDAY NIGHT FOLLOWED BY HIGH
PRESSURE EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 650 PM THURSDAY...LINE OF CONVECTION ACROSS THE EASTERN
PIEDMONT MAY AFFECT OUR COASTAL PLAINS COUNTIES OVER THE NEXT
SEVERAL HOURS. LATEST 3KM HRRR SHOWS THIS WITH SOME OF THE
ACTIVITY MAKING CLOSE TO THE COAST BY MORNING. HAVE TWEAKED POPS
TO HIGH CHANCE INLAND TAPERING BACK TO SLIGHT CHANCE COAST. STORMS
HAVE HAD THE HISTORY OF PRODUCING HEAVY RAINFALL...FREQUENT
LIGHTNING AND A BIT OF WIND DAMAGE NEAR THE NORTH
CAROLINA/VIRGINIA BORDER. AIRMASS STILL QUITE UNSTABLE ACROSS OUR
REGION...BUT WOULD EXPECT TO STORMS TO WEAKEN SOME WITH LOSS OF
HEATING OVER THE NEXT 2-3 HOURS. ANOTHER WARM/MUGGY NIGHT WITH
LOWS RANGING FROM LOW 70S DEEP INLAND TO UPPER 70S BEACHES.
REMNANT CONVECTIVE CLOUD DEBRIS/INCREASING CLOUDINESS OVERNIGHT
SHUD DETER WIDESPREAD FOG FORMATION ALTHO SOME PATCHY FOG
ESPECIALLY WHERE ANY PRECIP HAS FALLEN WILL BE POSSIBLE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
AS OF 320 PM THU...SFC TROF SLOWLY PUSHES INTO THE FORECAST AREA
FRIDAY AND MAY HELP FOCUS INCREASING PRECIP CHANCES DURING DIURNAL
CYCLE AIDED BY APPROACH OF WEAK MID LEVEL TROF DURING THE
AFTERNOON. WILL CAP POPS AT GOOD CHANCE FOR NOW GIVEN THE
GENERALLY WEAK FORCING MECHANISMS BUT PRECIP CHANCES MAY NEED TO
BE RAISED IF LATER MODELS RUNS SUPPORT A WETTER SCENARIO.
INSTABILITY WILL BE LACKING FRIDAY SO NOT EXPECTING MUCH OF SEVERE
THREAT. NOT AS WARM TOMORROW AS CLOUDS WILL HELP HOLD TEMPS IN THE
MID AND UPPER 80S BUT WITH DEW POINTS REMAINING IN THE 70S, HEAT
INDICES WILL REACH INTO THE LOW 90S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
AS OF 310 PM THU...UNSETTLED THIS WEEKEND AS STRONG FRONTAL
SYSTEM IMPACTS THE REGION...THEN DRIER AND COOLER FOR NEXT WEEK.
A STRONG COLD FRONT WILL APPROACH THE REGION FRI NIGHT AND SAT AS
ASSOCIATED UPPER LEVEL TROUGH DEEPENS TO THE WEST. SPC HAS ENC
OUTLOOKED IN MARGINAL RISK FOR SVR TSTMS SAT. DEEP SW FLOW
CONTINUES AHEAD OF THE FRONT WITH THE REGION IN THE WARM SECTOR.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH
GOOD FORCING AND INCREASING SHEAR. AT THIS TIME THINK THE BEST
CHANCE FOR STRONG/SEVERE STORMS WOULD BE LATE AFTERNOON AND EARLY
EVENING...WITH THE MAIN THREATS DAMAGING WIND GUSTS AND LOCALLY
HEAVY RAINFALL. LATEST 12Z GUIDANCE HAS SLOWED THE BOUNDARY AND
ASSOCIATED PRECIP SLIGHTLY. THE LIMITING FACTOR CONTINUES TO BE
INSTABILITY. THOUGH MORE INSTABILITY COULD BE REALIZED IF WE SEE
SOME BREAKS IN THE CLOUDS. ADJUSTED POPS SLIGHTLY...THOUGH
CONTINUED HIGH CHANCE INCREASING TO LIKELY SAT EVENING/NIGHT.
UPPER LOW AND TROUGH STRENGTHEN TO THE NORTH SUNDAY AS TRAILING
COLD FRONT PUSHES THROUGH THE AREA. GFS STILL SLIGHTLY FASTER THAN
THE ECMWF WITH THE FRONTAL PASSAGE...BUT EXPECT FRONT TO MOVE
THROUGH LATE SUN/SUN EVENING. DRIER AND COOLER AIR WILL BE
GRADUALLY FILTERING INTO THE REGION WITH PRECIP TAPERING OFF FROM
WEST TO EAST.
HIGH PRESSURE WILL BUILD OVER THE AREA MONDAY AS UPPER TROUGH
PUSHES OFF THE EAST COAST. HIGH WILL REMAIN ANCHORED OVER THE
AREA THROUGH THURSDAY. VERY PLEASANT WEATHER EXPECTED WITH THE
REGION SEEING THE FIRST GLIMPSE OF FALL...AS DEWPOINTS DROP INTO
THE 50S. LOW LEVEL THICKNESS VALUES SUPPORT TEMPS A FEW DEGREES
BELOW NORMAL...WITH HIGHS IN THE UPPER 70S/LOW 80S AND OVERNIGHT
LOWS IN THE MID/UPPER 50S INLAND AND LOW/UPPER 60S ALONG THE
COAST.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
SHORT TERM /THROUGH 00Z SATURDAY/...
AS OF 655 PM THURSDAY...SCATTERED THUNDERSTORMS MOVING OFF THE
EASTERN PIEDMONT MAY IMPACT THE KPGV/KISO TAF SITES THROUGH LATE
EVENING. LESSER CHANCES OF CONVECTION AT KEWN/KOAJ. THINK DEBRIS
CLOUDINESS FROM THIS CONVECTION ACCOMPANIED BY WEAK LOW-LEVEL
MIXING SHOULD PRECLUDE ANY WIDESPREAD FOG FORMATION
OVERNIGHT...ALTHOUGH A FEW PATCHES OF DENSE FOG WILL BE POSSIBLE
IN AREAS THAT RECEIVE RAINFALL. VFR CONDITIONS SHOULD PREVAIL
THROUGH MID-AFTERNOON FRIDAY AS WILL LIKELY BE DELAYED INTO THE
AFTERNOON.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 310 PM THU...PERIODS OF SUB-VFR WILL BE POSSIBLE FRI NIGHT
THROUGH SUNDAY...WITH SCATTERED TO NUMEROUS SHOWER/TSTMS AHEAD OF
A STRONG COLD FRONT. PRED VFR CONDITIONS SHOULD RETURN BY LATE
SUNDAY AS A COLD FRONT PUSHES THROUGH THE TERMINALS.
&&
.MARINE...
SHORT TERM /THROUGH FRIDAY/...
AS OF 7 PM THURSDAY...GRADIENT BETWEEN APPROACHING FRONTAL TROUGH AND
HIGH PRESSURE OFFSHORE WILL CONTINUE TO CREATE SW WINDS OF 10 TO
20 KNOTS WITH FREQUENT GUSTS TO AROUND 25 KNOTS OVER THE PAMLICO
SOUND AND CENTRAL AND SOUTHERN WATERS. SMALL CRAFT ADVISORIES WILL
REMAIN IN EFFECT INTO EARLY FRIDAY MORNING. THE TROF PUSHES INTO
THE MARINE AREA FRIDAY WITH WINDS SHIFTING NORTH AND BECOMING
LIGHT OVER NORTHERN COASTAL WATERS, WHILE REMAINING SW AT MODERATE
SPEEDS OVER SOUTHERN AREAS DURING THE AFTERNOON.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 310 PM THU...A STRONG COLD FRONT WILL APPROACH THE WATERS
FROM THE WEST FRIDAY NIGHT AND SATURDAY. PRESSURE GRADIENT WILL
TIGHTEN WITH SWLY WINDS INCREASING TO 15-25KT AND SEAS BUILDING TO
4-6FT. PERIOD OF SCA CONDITIONS EXPECTED TO DEVELOP EARLY SAT
EVENING AND CONTINUE INTO EARLY SUN MORNING...MAINLY SOUTH OF
OREGON INLET. SW/WSW 10-20KT CONTINUES SUN WITH SEAS 2-5FT. THE
FRONT WILL MOVE THROUGH THE WATERS LATE SUN/SUN EVENING...WITH
HIGH PRESSURE BUILDING IN BEHIND THE FRONT. HIGH PRESSURE WILL
REMAIN ANCHORED OVER THE AREA MONDAY AND TUESDAY. WINDS BECOMING
N/NW LESS THAN 15KT FOR MON AND SEAS 2-4FT...AND 10KT OR LESS TUE
WITH SEAS 1-3FT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EDT FRIDAY FOR AMZ135-152-154-
156-158.
&&
$$
SYNOPSIS...BTC
NEAR TERM...CTC
SHORT TERM...BTC
LONG TERM...CQD
AVIATION...BTC/CTC/CQD
MARINE...BTC/CTC/CQD
AREA FORECAST DISCUSSION
NWS TULSA OK
355 PM CDT THU SEP 10 2015
.DISCUSSION...
A cold front will move south across the area late tonight and
Friday morning accompanied by scattered to numerous showers and
thunderstorms. The HRRR is much quicker moving convection into and
out of the area than most other models and have leaned towards
this solution. A limited severe risk will exist especially near
the Kansas and Missouri borders, and this is also the area where
the greatest storm coverage is expected.
Much cooler and drier air will move into the area for the weekend
bringing our first taste of fall. Southerly winds will return and
increase early next week resulting in a quick warmup. By the
latter half of next week, temperatures will be several degrees
above normal, and higher humidity levels will return as well. Rain
chances look like they will hold off until the very end of the
week when a frontal boundary will approach from the north.
Stayed close to guidance temperatures the next couple days.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 67 79 53 76 / 60 30 0 0
FSM 69 82 56 78 / 40 40 0 0
MLC 68 82 56 78 / 30 30 0 0
BVO 65 78 50 75 / 80 20 0 0
FYV 64 75 49 71 / 60 40 0 0
BYV 63 75 50 71 / 80 40 0 0
MKO 67 79 53 76 / 40 30 0 0
MIO 64 76 49 73 / 90 30 0 0
F10 68 79 55 77 / 40 30 0 0
HHW 68 88 59 81 / 20 20 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...18
LONG TERM....05
PLATE
AREA FORECAST DISCUSSION
NWS NORMAN OK
250 PM CDT THU SEP 10 2015
.DISCUSSION...
PRIMARY FORECAST CONCERN IS FOCUSED ON PRECIPITATION CHANCES TONIGHT
THROUGH FRIDAY IN RESPONSE TO A COLD FRONT MOVING ACROSS THE AREA.
CURRENTLY... 19Z SFC ANALYSIS PLACES THE COLD FRONT NEAR THE NE/KS
BORDER... WITH INCREASING CU DEVELOPMENT ALONG AND AHEAD OF THE
FRONT ACROSS NRN INTO CENTRAL KS. THIS FRONT WILL CONTINUE TO PUSH
SOUTHWARD THROUGH THE AFTN INTO THE EVENING... APPROACHING THE OK/KS
BORDER THROUGH THIS EVENING. CONTINUITY BETWEEN TRADITIONAL AND
MESOSCALE GUIDANCE REMAINS DECENT. THE HRRR AND HIRES WRFS CONTINUE
TO GENERATE CONVECTION WITH THE SFC TROUGH OVER THE PANHANDLES
THROUGH 00Z... THE 12Z NAM IS A STEP SLOWER... BUT SIMILAR. GIVEN
INCREASING DPTS THIS AFTN AND AN INCREASING ISENTROPIC RESPONSE INTO
THE EVENING ACROSS NWRN OK... FELT COMFORTABLE TO INCREASE PRECIP
CHCS IN THE NW BETWEEN 00-06Z. EXPECT PRECIP COVERAGE TO INCREASE
INCREMENTALLY OVERNIGHT WITH THE BEST CHANCES AFTER MIDNIGHT THROUGH
SUNRISE ACROSS NRN AND NERN OK. AS FOR SEVERE CHANCES... MODEST ML-
CAPE VALUES 1000-1700 J/KG ARE POSSIBLE THIS EVENING AND
OVERNIGHT... WITH 20 TO 30 KTS OF 0-6KM SHEAR. LOOKING AT BUFR
SOUNDINGS... MOST OF THIS INSTABILITY IS WELL ELEVATED... WITH ANY
STRONGER STORMS DEVELOPING A HAIL OR WIND THREAT... QUARTER TO HALF
DOLLAR SIZE HAIL AND 60 MPH WINDS. OVERALL... THE CHANCE FOR SEVERE
STORMS WILL RESIDE WITHIN A NARROW WINDOW OF TIME ACROSS NRN OK THIS
EVENING THROUGH SUNSET.
FRIDAY... SCATTERED SHOWERS AND THUNDERSTORMS WILL LIKELY BE ONGOING
AROUND SUNRISE ACROSS NERN INTO CENTRAL OK. CHANCES WILL CONTINUE
THROUGH THE AFTN ACROSS MUCH OF THE REGION AS THE COLD FRONT PUSHES
TOWARDS THE RED RIVER THROUGH THE AFTN. INTO THE LATE
AFTN/EVENING... SOME STEEPER LAPSE RATES MAY DEVELOP... RESULTING IN
SOME STRONGER THUNDERSTORMS NEAR THE RED RIVER. HOWEVER... SEVERE
CHANCES REMAIN LOW.
SHOULD BE A WONDERFUL WEEKEND AS TEMPS REMAIN MILD... WITH HIGHS IN
THE UPPER 70S AND LOWER 80S EACH DAY. TEMPS WILL START TO REBOUND
EARLY NEXT WEEK AS SRLY FLOW RETURNS AND TROUGHING DEVELOPS OVER THE
WRN US MON-TUE. OVERALL... THE FORECAST REMAINS DRY THROUGH MUCH OF
NEXT WEEK... WITH THE NEXT BEST CHANCE FOR PRECIP LATE NEXT WEEK AS
A FRONTAL BOUNDARY APPROACHES THE REGION.
JTK
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 67 79 56 77 / 20 20 10 0
HOBART OK 68 80 57 81 / 10 20 10 0
WICHITA FALLS TX 69 86 59 83 / 0 30 20 0
GAGE OK 62 78 52 80 / 30 20 10 0
PONCA CITY OK 65 78 50 77 / 60 30 0 0
DURANT OK 70 86 58 81 / 0 30 20 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
452 PM EDT THU SEP 10 2015
.SYNOPSIS...
A COLD FRONT AND UPPER TROUGH WILL SLOWLY SWEEP OVER THE SOUTHERN
APPALACHIAN REGION LATE THIS WEEK. BY EARLY NEXT WEEK...A COOL AND
DRY AIR MASS IS FORECAST TO SETTLE OVER THE WESTERN CAROLINAS AND
NORTHEAST GEORGIA. MOISTURE SHOULD BEGIN TO INCREASE OVER THE REGION
BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
415 PM UPDATE...WHILE THERE SO FAR HAS BEEN LITTLE CUMULUS
DEVELOPMENT IN THE I-85 CORRIDOR THIS AREA MAY BEGIN TO SEE
CONVECTIVE COVERAGE AS OUTFLOW BOUNDARIES FROM NC CONVECTION
DRIFT SWD. THE AREAS OF THE NC PIEDMONT AND LOWER SAVANNAH
RIVER VALLEY CURRENTLY SEEING SCT ACTIVITY SHOULD CONTINUE TO
SEE THIS BUBBLE UNTIL HEATING CEASES...BUT LITTLE EXPANSION IS
EXPECTED. SEVERAL RUNS OF THE HRRR HAVE SHOWN NEW DEVELOPMENT NEAR
SUNSET APPARENTLY AS WIND SHIFT LINE AND/OR OUTFLOW BOUNDARIES
FOCUS REMNANT BUOYANCY. STILL THINK ANY LINGERING ACTIVITY WILL
RAPIDLY DIMINISH IN THE 03-06Z TIMEFRAME.
AS OF 225 PM...THE AXIS OF AN UPPER TROF CONTINUES TO PUSH
EAST...ENTERING THE NC MTNS ATTM. MEANWHILE...A COLD FRONT WAS
ANALYZED WINDING FROM THE MID ATLANTIC TO THE TN VALLEY...TO THE
SOUTHERN PLAINS. THE AIR MASS ALONG AND SOUTH OF THE BNDRY IS QUITE
MOIST...WITH DEWPTS IN THE UPR 60S TO LWR 70S. THIS HAS RESULTED
IN SBCAPE IN THE 1000 TO 2000 J/KG RANGE...EVEN HIGHER JUST SOUTH
AND EAST OF THE CWFA. SO EXPECT CONVECTION TO CONTINUE TO INCREASE
IN COVERAGE AND INTENSITY ACRS THE AREA THRU THE AFTN.
CONVECTION SHUD DIMINISH THIS EVENING AS ATMOS STABILIZES AND UPPER
ENERGY EXITS TO THE EAST. THE COLD FRONT WILL STALL IN THE MTNS
FOR MUCH OF THE NIGHT...WHILE NWLY LLVL FLOW HELPS SCOUR OUT CLOUD
COVER. SO PATCHY FOG AND STRATUS IS EXPECTED TO DEVELOP ACRS THE
AREA...ESP WHERE THE HEAVIEST RAIN FALLS AND IN THE MTN VALLEYS.
TEMPS WILL DROP A CATEGORY OR TWO COOLER THAN THIS MORNING/S LOWS
FOR FRIDAY MORNING.
FRIDAY...THE CWFA WILL BE IN BETWEEN SHORTWAVE TROFS AND BETWEEN
SFC FRONTS. LLVL FLOW WILL REMAIN WLY TO NWLY...LIMITING MOISTURE
AND LLVL CONVERGENCE. SO EXPECT ONLY ISOLATED TO WIDELY SCATTERED
CONVECTION WITH PEAK HEATING FRIDAY AFTN. TEMPS WILL BE A CATEGORY
OR TWO ABOVE NORMAL.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 215 PM THURSDAY...LINGERING SCATTERED/ISOLATED DIURNAL
CONVECTION IS EXPECTED TO WANE FRI EVENING...BUT POPS WILL INCREASE
AGAIN TOWARD DAYBREAK ACROSS THE MTNS...AS A BAND OF DEEP MOISTURE
ASSOCIATED WITH STRONG HEIGHT FALLS AND ASSOCIATED FRONTAL SURGE
APPROACHES THE FORECAST AREA. WHILE THE MOIST BAND IS EXPECTED TO
DIMINISH AS IT MOVES QUICKLY ACROSS THE FORECAST AREA DURING THE
MORNING...MID-LEVEL DRY SLOT WILL OVERSPREAD THE AREA DURING THE
AFTERNOON...WITH PART OF THE FRONT LIKELY GETTING HUNG UP A BIT
ACROSS THE MOUNTAINS...LIKELY NOT COMPLETELY CLEARING THE AREA UNTIL
A POTENT SHORT WAVE TROUGH MOVES ACROSS THE AREA DURING THE EVENING.
AS A RESULT...THERE SHOULD BE PLENTY OF LOW LEVEL MOISTURE AND
WARMTH LINGERING THROUGH THE DAY TO SUPPORT MODEST LEVELS OF
INSTABILITY. TERRAIN EFFECTS AND THE FRONT SHOULD PROVIDE FOCI FOR
SCATTERED CONVECTIVE DEVELOPMENT INTO THE AFTERNOON AND EARLY
EVENING...ESP FROM THE BLUE RIDGE EAST...PRIMARILY WARRANTING CHANCE
POPS.
WITH CANADIAN HIGH PRESSURE BUILDING INTO THE REGION IN THE WAKE OF
DEPARTING TROUGH/COLD FRONT...SUNDAY SHAPES UP TO BE A SPECTACULAR
EARLY TASTE OF AUTUMN...WITH MAXES EXPECTED IN THE 70S AND DEWPOINTS
LIKELY FALLING INTO THE 40S BY AFTERNOON.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 225 PM THURSDAY...THE EARLY PART OF THE MEDIUM RANGE WILL BE
DOMINATED BY AN ANOMALOUSLY DEEP...YET PROGRESSIVE EAST COAST LONG
WAVE TROUGH AND ASSOCIATED CANADIAN HIGH PRESSURE. THIS WILL SUPPORT
A CONTINUATION OF EARLY FALL-LIKE WEATHER...WITH TEMPS/DEWPOINTS
EXPECTED TO REMAIN BELOW CLIMO THROUGH AT LEAST TUESDAY. IN FACT...
MON MORNING IS EXPECTED TO BE DOWNRIGHT CHILLY ACROSS THE HIGH
ELEVATIONS...WITH TEMPS LIKELY DIPPING TO NEAR 40 ABOVE 4000 FEET OR
SO. HEIGHT RISES BY THE END OF THE PERIOD WILL RESULT IN TEMPS
CREEPING BACK TOWARD CLIMO...ALTHOUGH WITH SURFACE RIDGE AXIS
EXPECTED TO PERSIST ACROSS THE REGION...DEWPOINTS SHOULD BE SLOWER
TO RECOVER...AND IT APPEARS CHANCES FOR ANY DIURNAL CONVECTION...OR
PRECIP OF ANY STRIPE WILL BE BELOW 20 PERCENT THROUGH THE PERIOD.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
AT KCLT /21Z UPDATE/...A COLD FRONT WILL CROSS THE AREA TONIGHT FROM
THE NW. SCATTERED TO NUMEROUS SHRA AND TSRA WILL DEVELOP ALONG AND
AHEAD OF THE FRONT THIS AFTN. THERE WILL ALSO BE SOME LOW-END GUSTS
OUT OF THE SW...WHICH MAY BECOME VARIABLE /BUT MORE LIKELY W TO N/
IF ANY TSTMS ARE NEARBY. WILL CONTINUE TO HIGHLIGHT THIS IN A TEMPO
GROUP THRU 24Z. OVERNIGHT...EXPECT WINDS TO DIMINISH...WITH SOME
CLEARING OF SKIES. SO THERE MAY BE SOME PATCHY STRATUS AND/OR FOG
AROUND DAYBREAK. CONFIDENCE IS LIMITED BY THE POTENTIAL DOWNSLOPE
FLOW BEHIND THE FRONT...AND THE FACT THAT ANY PRECIP THIS AFTN WILL
IMPACT THE SEVERITY OF OVERNIGHT CLOUD/FOG DEVELOPMENT. WINDS WILL
SWITCH TO NW WITH THE FROPA AROUND 12Z...BUT SHUD REMAIN LIGHT.
ELSEWHERE...HAVE VCTS AND TEMPO GROUPS AT ALL SITES TO HIGHLIGHT
THREATS FROM ONGOING CONVECTION...THOUGH COVERAGE IS NOT EXPECTED
TO BECOME ANY BETTER THAN SCATTERED. WINDS WILL BE MARGINALLY
GUSTY ACRS THE UPSTATE OUT OF THE SW. WINDS WILL SHIFT OUT OF
THE NW AT KAVL BY EARLY EVENING...AND AT THE REST OF THE SITES
OVERNIGHT...AS A COLD FRONT PASSES THRU. WINDS WILL BE LIGHT AND
SKIES WILL SEE SOME GRADUAL CLEARING. SO PATCHY FOG AND/OR STRATUS
IS POSSIBLE...ESP WHERE RAIN FALLS AND IN THE MTN VALLEYS.
OUTLOOK...UNSETTLED CONDITIONS WILL CONTINUE THROUGH THE WEEKEND
AS A FRONT STALLS IN THE REGION...AND AN UPPER LEVEL LOW PRESSURE
SYSTEM DRIFTS EAST THROUGH THE APPALACHIANS. MTN VALLEY FOG AND
STRATUS ARE POSSIBLE EACH MORNING...WITH SCATTERED THUNDERSTORMS
MAINLY IN THE AFTN. DRIER CONDITIONS WILL ARRIVE EARLY NEXT WEEK.
CONFIDENCE TABLE...
21-03Z 03-09Z 09-15Z 15-18Z
KCLT HIGH 100% HIGH 100% MED 75% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 88% HIGH 94% HIGH 81% HIGH 97%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
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...RWH
NEAR TERM...ARK/WIMBERLEY
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...ARK/WIMBERLEY
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
353 PM CDT THU SEP 10 2015
.DISCUSSION...
RADAR THIS AFTERNOON SHOWS WIDESPREAD SHOWER AND THUNDERSTORM
ACTIVITY WITH THE STRONGEST STORMS OVER E HARRIS COUNTY WHERE
STORMS ARE PRODUCING RAIN RATES OF 2 INCHES AN HOUR. THERE IS ALSO
A BAND OF ACTIVITY ALONG A STALLED FRONTAL BOUNDARY FROM AUSTIN TO
COLLEGE STATION EAST TO JASPER. LATEST TRENDS WITH THE HRRR MODEL
SEEM TO SHOW ACTIVITY ENDING BETWEEN 00-03Z THIS EVENING.
WATER VAPOR IMAGE LOOP SHOWS A WEAK JET STREAK/SHORTWAVE PUSHING
THROUGH THE REGION THIS AFTERNOON WHICH MAY BE HELPING TO ENHANCE
CONVECTION. OVERALL UPPER LEVEL PATTERN IS ON TRACK WITH A
STRONGER SHORTWAVE TROUGH DEVELOPING OVER THE N ROCKIES WHICH WILL
HELP AMPLIFY THE TROUGH FROM SW OF HUDSON BAY TO THE UPPER
MIDWEST TONIGHT INTO FRIDAY.
WITH PRECIP WATER VALUES OVER 2 INCHES TOMORROW AND FAVORABLE
UPPER LEVEL PATTERN...FORECAST WILL HOLD ONTO 60/70 POPS.
GFS/NAM/ECMWF ALL SUPPORT SHOWER AND THUNDERSTORM ACTIVITY SIMILAR
TO TODAY`S ACTIVITY. THERE WILL ALSO BE AN ADDED TROUGH AXIS THAT
PUSHES THROUGH FRI TO HELP INCREASE LARGE SCALE LIFT. AS HAS BEEN
THE CASE TODAY...EXPECTING A GENERAL 1 TO 2 INCHES OF RAIN WITH
ISOLATED HIGHER AMOUNTS. SINCE CONVECTION WILL BE PULSE
TYPE...VERY WELL COULD HAVE AREAS THAT GET NO RAINFALL BUT THEN
AREAS THAT GET TOO MUCH. THERE MAY BE FLOODING ASSOCIATED WITH ANY
OF THE HIGHER AMOUNTS BUT A WIDESPREAD FLOOD THREAT IS NOT
EXPECTED AT THIS TIME.
GIVEN THE MORE AMPLIFIED PATTERN FRIDAY INTO SATURDAY...COLD FRONT
WILL BE PUSHING THROUGH THE AREA AND OFF THE COAST. LATEST TIMING
FROM THE NAM/GFS/ECMWF SHOWS IT REACHING COLLEGE
STATION TO HUNTSVILLE AROUND 1-3AM SATURDAY...REACHING HOUSTON
CLOSER TO 6-8AM AND OFF THE COAST BEFORE NOON SATURDAY. WINDS
SHOULD SHIFT TO THE N/NE. THE MUCH DRIER COOLER AIRMASS WILL
LIKELY LAG BEHIND THE FRONT AND NOT ARRIVE UNTIL LATER IN THE
AFTERNOON AND OVERNIGHT. THERE DOES NOT APPEAR TO BE MUCH OF A
CHANCE OF THUNDERSTORMS WITH THE FRONT BUT GIVEN THE MOISTURE
CONTENT WILL AT LEAST HAVE A 30 PERCENT IN THE FORECAST.
WEATHER CONDITIONS SUNDAY/MONDAY WILL CERTAINLY GIVE EVERYONE A
GOOD TASTE OF FALL WEATHER WITH LOW TEMPS IN THE LOW 60S...PERHAPS
UPPER 50S FOR AREAS NORTH OF HOUSTON. HIGH TEMPERATURES WILL BE
IN THE MID 80S. ENJOY IT WHILE YOU CAN BECAUSE THE MOISTURE SHOULD
BE BACK TUESDAY THROUGH THURSDAY NEXT WEEK.
EXTENDED FORECAST...STILL VERY UNCERTAIN WITH REGARDS TO A SURGE
OF TROPICAL MOISTURE EXPECTED TO PUSH INTO THE AREA TUESDAY AND
WEDNESDAY. GFS HAS BEEN VERY CONSISTENT AND HAS HAD ENSEMBLE
SUPPORT OF MAINLY A SURFACE COASTAL TROUGH DEVELOPING IN THE W
GULF AND PUSHING NORTH TOWARDS THE AREA. THE ECMWF THE LAST 2 RUNS
HAS NOW TAPPED THE BREAKS ON TROPICAL CYCLONE FORMATION ALTHOUGH
IT STILL WANTS TO DEVELOP SOME TYPE OF LOW PRESSURE WHICH IT
SLOWLY PUSHES TOWARDS THE LOWER TEXAS COAST NEXT WEEK. GFS
CONTINUES TO HOLD ONTO SOME W SHEAR ACROSS THE N GULF WITH THE
ECMWF STILL HAVING SOMEWHAT OF A RIDGE. THE DIFFERENCES IN THE
PATTERNS WILL LIKELY DETERMINE HOW MUCH SHEAR DEVELOPS OVER THE NW
GULF AND IF THERE IS ANY DEVELOPMENT. AT THIS POINT IT DOES NOT
LOOK LIKELY BUT WE WILL STILL NEED TO MONITOR FORECAST DATA.
39
&&
.AVIATION...
FAIRLY ACTIVE AFTN WITH CONVECTION FILLING IN. MODELS INDICATE PER-
HAPS ANOTHER DAY OF UNSETTLED WX TOMORROW. WILL START WITH VCSH FOR
THE MORNING HRS THEN TRANSITIONING TO VCTS FOR THE AFTN. BUT IN THE
MEANTIME...MAY HAVE TO INCLUDE A BRIEF MVFR CIG FOR NRN SITES GIVEN
THE WIDESPREAD RAINS/EXPECTED CLEARING OVERNIGHT. 41
&&
.MARINE...
NOT TOO MANY CHANGES WITH THE SHORT TERM PART OF THE FCST AS MOSTLY
LIGHT ONSHORE WINDS PREVAIL...ALONG WITH THE WIDESPREAD STORMS THRU
TOMORROW(FRI). MODELS STILL IN DECENT AGREEMENT WITH THE PASSAGE OF
A WEAK COLD FRONT INTO THE COASTAL WATERS EARLY SAT MORNING. GENER-
ALLY LIGHT/MODERATE NE WINDS TO DEVELOP IN ITS WAKE...FROM SAT AFTN
INTO SUN MORNING. AS THIS FRONT DISSIPATES OVER THE GULF AND A WEAK
TROF OF LOW PRESSURE BEGINS TO DEVELOP NEAR THE LOWER TX COAST...WE
SHOULD START SEEING A MORE EASTERLY FETCH DEVELOP OVER THE UPPER TX
COAST SUN AFTN/EVE. THIS FEATURE WILL THEN HELP TO BRING PERIODS OF
SHRA/TSRA AND PERHAPS A PROLONGED PERIOD OF ESE WINDS TO THE REGION
FOR THE FIRST HALF OF NEXT WEEK. 41
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 89 71 86 61 / 30 40 30 10 10
HOUSTON (IAH) 74 87 71 86 62 / 40 60 30 20 10
GALVESTON (GLS) 78 84 76 86 72 / 50 70 50 30 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...39
AVIATION/MARINE...41
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
334 PM CDT THU SEP 10 2015
.SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...ABUNDANT MOISTURE
WITH OVER 2 INCH PWATS REMAINS OVER SOUTH TEXAS WITH SCATTERED
CONVECTION ONGOING...WITH CONVECTION EXPECTED TO DWINDLE THROUGH
THE EVENING. CHALLENGE GOES INTO TIMING OF CONVECTION FOR FRIDAY.
TEXAS TECH WRF AND HRRR BOTH HAVE HAD A PRETTY GOOD HOLD
CONVECTION TODAY...AND LOOKING AT WHAT THEY SHOW FOR FRIDAY...THEY
KEEP A MUCH SLOWER TREND FOR CONVECTION...WITH THINGS MOSTLY DRY
THROUGH MID MORNING FRIDAY. DUE TO AN INCREASE IN H925 FLOW AND A
SHORTWAVE MOVING SOUTH ALONG THE RIO GRANDE OVERNIGHT KEPT IN POPS
FOR TONIGHT...BUT DUE TO A BIT OF SUBSIDENCE AHEAD OF THE
SOUTHWARD PROGRESSING TROUGH...DID CUT BACK FROM PREVIOUS
FORECAST PACKAGE. CHANCES FOR RAIN WILL INCREASE THROUGH THE
DAY...WITH THE BEST TIMING MORE DURING THE AFTERNOON THROUGH
OVERNIGHT HOURS...DUE TO MORE CONVERGENCE AND INCREASED LIFT WITH
THE TROUGH SHIFTING SOUTH. AS FOR TEMPERATURES...TRENDED ON THE
COOLER SIDE FROM THE EXPECTED CLOUD COVERAGE AND RAIN CHANCES.
&&
.LONG TERM (SATURDAY THROUGH THURSDAY)...THE MODELS ARE FAIRLY
CONSISTENT IN PUSHING A COLD FRONT THROUGH THE CWA BY SATURDAY
NIGHT. SUFFICIENT MOISTURE/INSTABILITY AND KINEMATIC FORCING WL
EXIST ALONG AND AHEAD OF THE FRONT TO MAINTAIN SLIGHT CHC TO CHC
POPS ON SATURDAY. DRY AIR ADVECTION AIDED BY A WK TO MODERATE
NORTHEAST FLOW WL PRODUCE ABUNDANT SUNSHINE AND MUCH LOWER
HUMIDITIES FOR SUNDAY. THE ECMWF 12Z SOLUTION HAS NOW COME MORE IN
LINE WITH THE WEAKER GFS REFLECTION OF THE AREA OF LOW PRESSURE THAT
MAY DEVELOP OVER THE SW GULF BY SUNDAY AND MONDAY. THE CURRENT
THINKING IS THAT THIS SYSTEM WL REMAIN WK AND REMAIN TO OUR SOUTH
POSSIBLY MOVING INTO NORTHERN MEXICO NEAR TAMPICO BY TUESDAY. THE
NET EFFECT WL LKLY BE TO KEEP MOST OF THE DEEP TROPICAL MOISTURE TO
THE SOUTH. HOWEVER...DO EXPECT MOISTURE TRANSPORT NEXT WEEK AS THE
BOUNDARY LAYER FLOW BECOMES MORE SOUTHEASTERLY BY MONDAY. THERE WL
LKLY BE SUFFICIENT MOISTURE TO WARRANT SLIGHT CHC TO CHC POPS FOR
MOSTLY THE WATERS AND COASTAL BEND FROM LATE MONDAY THROUGH
THURSDAY. OVERALL DID TRIM THESE POPS BACK FOR NEXT WEEK FROM PRIOR
REASONING. SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED DURING THE
WEEKEND AND THEN WL SLOWLY TRANSITION TO MORE NORMAL MID SEPTEMBER
VALUES THROUGH NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 78 89 74 88 71 / 40 60 60 40 20
VICTORIA 74 86 71 87 64 / 40 60 40 20 10
LAREDO 78 93 73 90 71 / 40 60 60 30 20
ALICE 75 90 72 88 68 / 40 60 60 40 20
ROCKPORT 79 87 75 87 72 / 40 60 60 40 20
COTULLA 76 90 73 91 67 / 40 60 40 20 10
KINGSVILLE 77 91 73 88 70 / 40 60 60 40 20
NAVY CORPUS 79 87 76 87 74 / 40 60 60 40 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
CB/85...SHORT TERM
MB/80...LONG TERM
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
304 PM CDT THU SEP 10 2015
.SHORT TERM...
A PROMINENT FEATURE IN THE WEATHER TODAY HAS BEEN A BAND OF CIRRUS
ARCING FROM CENTRAL ARIZONA ACROSS WEST TEXAS. THIS IS ASSOCIATED
WITH SOME TROPICAL MOISTURE CAUGHT UP IN THE CIRCULATION OF DECAYING
TROPICAL STORM LINDA OFF THE WEST COAST OF BAJA. UPPER-AIR ANALYSIS
SHOWS THAT THIS MOISTURE IS LIMITED TO THE UPPER TROPOSPHERE WITH
MID-LEVELS REMAINING FAIRLY DRY AND UNSUPPORTIVE OF ANY CONVECTIVE
DEVELOPMENT. HOWEVER...WE ARE SEEING SOME DEVELOPMENT ACROSS NORTH-
CENTRAL NEW MEXICO IN VICINITY OF THE RATON MESA. NORTHWEST FLOW
ALOFT WILL CARRY THIS ACTIVITY TO THE SOUTHEAST THIS EVENING TOWARD
THE FAR SOUTHWEST TEXAS PANHANDLE ASSUMING IT SURVIVES THE TREK
ACROSS THE NORTHEAST NEW MEXICO PLAINS. THE HRRR IS ABOUT THE THE
ONLY MODEL THAT INDICATES THIS...BUT WE WILL MAINTAIN A SLIGHT
CHANCE MENTION ACROSS MUCH OF THE SRN TX PANHANDLE BETWEEN 00 AND 06
UTC TO ACCOUNT FOR THIS POSSIBILITY. BETTER T-STORM/RAIN CHANCES
SHOULD ARRIVE EARLY FRIDAY MORNING AS A FAIRLY SHARP COLD FRONT
MOVES IN FROM THE NORTH IN CONJUNCTION WITH A GLANCING BLOW FROM A
SHORTWAVE MOVING SOUTHEAST THROUGH THE PLAINS. THE FRONT IS
CURRENTLY MOVING INTO NORTHERN KANSAS AND THERE IS SOME UNCERTAINTY
REGARDING IT/S TIMING INTO OUR FORECAST AREA OWING TO THE IMPACT OF
CONVECTIVE OUTFLOWS ON THE FRONT. IN ADDITION...IT IS UNCERTAIN
WHETHER OR NOT THE FRONTOGENETIC FORCING WILL SYNCH UP WITH THE BEST
LARGE-SCALE ASCENT ASSOCIATED WITH THE PASSING WAVE. FINALLY...THE
TIMING OF THE FRONT...PASSING THROUGH THE AREA ROUGHLY BETWEEN 12
UTC AND 18 UTC...IS NOT OPTIMAL FOR THE GENERATION OF INSTABILITY
AVAILABLE FOR CONVECTION. WITH THIS IN MIND...WE HAVE KEPT POPS IN
THE CHANCE CATEGORY FOR THE AREA ON FRIDAY AS THE LINGERING
UNCERTAINTY DOES LEND ITSELF FOR LIKELY OR CATEGORICAL POPS. IN
GENERAL...GUIDANCE FAVORS A BROAD ZONE OR CLUSTER OF ALONG AND POST-
FRONTAL SHOWERS AND THUNDERSTORMS FRIDAY MORNING FOLLOWING THE FRONT
FROM NORTHEAST TO SOUTHWEST....AND GRADUALLY TAPERING OFF FROM THE
NORTHEAST DURING THE AFTERNOON. BREEZY NORTHEAST WINDS WILL DEVELOP
BEHIND THE FRONT AND LAST THROUGH THE AFTERNOON. TEMPERATURES WILL
BE MARKEDLY COOLER ACROSS THE NORTH...WITH HIGHS IN THE MID TO UPPER
70S ACROSS THE FAR SW TEXAS PANHANDLE AND NORTHERN SOUTH PLAINS.
DEPENDING ON THE TIMING OF THE FRONT...WE MAY STILL STILL SOME HIGH
TEMPS REACH 90 DOWN IN THE SOUTHERN ROLLING PLAINS.
.LONG TERM...
MID-LEVEL DRYING WILL ADVANCE SLOWLY SW BY FRIDAY EVENING IN THE
WAKE OF THE 850-700 MB COLD FRONT. THE DRIEST SURFACE RIDGING WILL
LAG UNTIL SATURDAY MORNING...SO POST-FRONTAL STRATUS AIDED BY E-NE
WINDS SHOULD LINGER ESPECIALLY ON THE CAPROCK BEFORE ERODING BY
MIDDAY SAT. SOME OF THIS STRATUS IS PROGGED TO BE SUFFICIENTLY THICK
FRI NIGHT THAT A FEW SHOWERS COULD MATERIALIZE FROM WEAK FN FORCING
ALONG THE AFOREMENTIONED ELEVATED FRONTAL LAYER...BUT POPS OVERALL
WERE SKIMMED BACK EVEN FURTHER THAN BEFORE.
SAT MORNING WILL SEE SURFACE WINDS VEER SELY BEHIND THE PROGRESSIVE
SURFACE RIDGE AND THIS PROCESS WILL AID IN WEAK ISENTROPIC LIFT
ACROSS THE WESTERN HALF OF THE CWA COINCIDENT WITH A MODEST AXIS OF
HIGHER PWATS. WHILE SATURATED DEPTHS ARE NOT MUCH TO WRITE ABOUT...
THE BRUNT OF THIS SATURATION IS BELOW 700 MB WHICH COULD BE WRUNG
OUT IN THE FORM OF SPRINKLES OR EVEN DRIZZLE PROVIDED STRATUS CAN
DESCEND LOW ENOUGH AT TIMES. CLEARING SKIES BY MIDDAY COULD OPEN THE
DOOR TO WEAK CAPE ACROSS EASTERN NM UNDERNEATH 10-20 KNOTS OF NW
FLOW...HOWEVER NO DISCERNIBLE BACKGROUND SUPPORT PRECLUDES FURTHER
POPS AT THIS TIME. EVEN WITH CLEARING...BELOW NORMAL HIGHS REMAIN ON
TRACK GIVEN OUR PROXIMITY TO THE SURFACE RIDGE. THIS COOL THEME WILL
BE SHORT LIVED AS SUNDAY AND BEYOND FEATURE LEE TROUGHING BENEATH
AMPLIFYING SW FLOW. SIDED CLOSE TO THE WARMEST MEX AND ECE MOS HIGHS
NEXT WEEK AS THIS LOOKS TO BE A VERY DRY AND BREEZY PATTERN FOR WEST
TX. SUCH DRY SOILS IN THIS SETUP ARGUE IN FAVOR OF A RATHER STRONG
DIURNAL TEMP RANGE...SO LOWS WERE NUDGED BELOW THE MILD SUPERBLEND
VALUES.
A SMALL WINDOW FOR MID-LEVEL MOISTENING MAY UNFOLD NEAR MIDWEEK AS A
BROAD TROUGH LIFTS NORTHEAST OUT OF THE FOUR CORNERS. MONSOONAL
MOISTURE ALOFT WILL LIKELY BE THINNED OUT BY THIS TIME...BUT SOME
UPTICK IN PWATS MAY BE REALIZED BY TUE AND WED AS THE SW FLOW TURNS
WEAKLY CYCLONIC. WHETHER THIS RESULTS IN PRECIP ALONG A DRYLINE
IN/NEAR OUR AREA IS TOO UNCERTAIN...ESPECIALLY WITH OUR REGION
RESIDING LARGELY SOUTH OF THE UPPER JET MAXIMA.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33/93
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1235 PM CDT THU SEP 10 2015
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...SHOWERS BEGINNING TO FORM ALONG THE COAST ATTM...WITH
GENERAL NORTHWARD MOVEMENT. EXPECT A COUPLE SHOWERS COULD REACH
KBRO AND KHRL EARLY THIS AFTERNOON...WITH BRIEF AND MINIMAL
CHANGES TO FLIGHT CONDITIONS. SKIES SHOULD REMAIN MOSTLY CLEAR
THROUGH THE NIGHT UNTIL JUST BEFORE DAWN. LOW CLOUDS MAY THICKEN
BETWEEN 09 AND 13Z...SO HAVE ADDED TEMPO GROUPS. MORE WIDESPREAD
SHOWERS AND THUNDERSTORMS LIKELY TO ARRIVE LATER TOMORROW
AFTERNOON AT LOCAL AIRPORTS.
&&
.PREV DISCUSSION... /ISSUED 556 AM CDT THU SEP 10 2015/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...LIGHT SOUTHEAST WINDS WITH A FEW PASSING CLOUDS
PREVAIL OVER DEEP SOUTH TEXAS THIS MORNING. SOME PATCHY LIGHT FOG
AND LOW CLOUD DECKS HAVE BEEN OBSERVED ACROSS THE REGION IN THE
PAST COUPLE OF HOURS. BRIEF MVFR CONDITIONS WILL BE POSSIBLE JUST
AFTER SUNRISE. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH THIS
LATE EVENING. WILL KEEP THE MENTION OF VCSH AT ALL TAF SITES AS
ISOLATED SEA BREEZE ACTIVITY IS POSSIBLE LATER TODAY. LIGHT
SOUTHEAST WINDS WILL BECOME MODERATE LATER THIS MORNING WITH GUSTS
AROUND 20 KNOTS IN THE AFTERNOON. WINDS WILL GRADUALLY WEAKEN THIS
EVENING WITH INCREASING LOW CLOUDS LATE TONIGHT.
PREV DISCUSSION... /ISSUED 422 AM CDT THU SEP 10 2015/
SHORT TERM /NOW THROUGH FRIDAY/...LATEST WATER VAPOR SATELLITE
IMAGERY SHOWS A 500MB RIDGE CENTERED OVER WEST TEXAS INTO NORTHERN
MEXICO AND OVER SOUTH FLORIDA WITH 500MB WEAKNESS OVER THE WESTERN
GULF OF MEXICO. BROWNSVILLE RADAR SHOWS ISOLATED ACTIVITY ACROSS THE
LOWER TEXAS GULF WATERS THIS MORNING. THE LATEST HRRR SUGGESTS
CONVECTION WILL INCREASE ACROSS THE GULF WATERS THROUGH SUNRISE. BRO
SOUNDING FROM WEDNESDAY EVENING INDICATES PRECIPITABLE WATER VALUES
OF 1.87 INCHES. EXCEPT FOR SOME PASSING HIGH CLOUDS...MOSTLY CLEAR
SKIES AND LIGHT WINDS PREVAIL ACROSS DEEP SOUTH TEXAS EARLY THIS
MORNING. A LITTLE GROUND FOG MAY DEVELOP AROUND SUNRISE BEFORE
QUICKLY DISSIPATING. NOTE...THE SURFACE OBSERVATION FROM EDINBURG IS
NOT REPRESENTATIVE TO CURRENT WEATHER CONDITIONS.
THE MAIN FORECAST ISSUE WILL BE THE RAIN CHANCES ACROSS DEEP SOUTH
TEXAS THROUGH THE FORECAST PERIOD. DEEP TROPICAL MOISTURE
/PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES/ COMBINED WITH DAY
TIME HEATING WILL SUPPORT ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS TODAY. HIGH TEMPERATURES TODAY WILL RANGE FROM THE
LOWER 90S NEAR THE COAST TO THE UPPER 90S ACROSS THE UPPER VALLEY.
RAIN CHANCES MAY LINGER ACROSS THE NORTHERN RANCHLANDS TONIGHT AS
THE GFS SUGGESTS. OTHERWISE...MOSTLY CLOUDY SKIES WITH LOW
TEMPERATURES GENERALLY IN THE MID TO UPPER 70S. THE HIGHEST RAIN
CHANCES WILL BE FRIDAY WITH PRECIPITABLE WATERS BETWEEN 2.2 TO 2.5
INCHES PER THE LATEST NAM/GFS. HIGH TEMPERATURES FRIDAY WILL BE A
FEW DEGREES LOWER DUE TO THE INCREASE IN RAIN CHANCES AND CLOUD
COVER.
ANY OF THE HEAVIER OR SLOWER-MOVING SHOWERS AND THUNDERSTORMS TODAY
AND FRIDAY WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL
WITH NUISANCE FLOODING ON ROADS AND IN LOW-LYING AREAS...ESPECIALLY
THOSE WITH A HISTORY OF FLOODING.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...ACTIVE WEATHER
PATTERN REMAINS FOR THE LONG TERM PORTION OF THE FORECAST. WEAK
COLD FRONT PASSES THROUGH THE BRO CWFA FRIDAY NIGHT...WITH
INVERTED SURFACE TROUGHINESS FORMING AND PERSISTING ALONG THE
LOWER TEXAS COAST AFTERWARDS. SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ARE FORECAST FOR FRIDAY NIGHT THROUGH SUNDAY...
WITH LOCALLY HEAVY RAINFALL POSSIBLE FRIDAY NIGHT AND SATURDAY
WITH DEEP TROPICAL MOISTURE IN PLACE. CONVECTION WILL BECOME MORE
ISOLATED SUNDAY NIGHT THROUGH THE END OF THE FORECAST AS THE FOCUS
OF THE ACTIVITY SHIFTS MORE OFFSHORE WITH WEAK LOW PRESSURE
POSSIBLY ATTEMPTING TO FORM OVER THE WESTERN GULF OF MEXICO.
TEMPERATURES WILL BE TEMPERED EARLY IN THE FORECAST PERIOD
COURTESY OF THE INCREASED CLOUDINESS AND OPPORTUNITIES FOR
RAINFALL...BUT SHOULD WARM UP TOWARDS THE MIDDLE AND END OF THE
FORECAST WITH LESSER CHANCES OF RAIN IN PLACE.
MARINE...NOW THROUGH FRIDAY...BUOY DATA AND OBSERVATION PLATFORMS
ALONG THE LOWER TEXAS COAST THIS MORNING INDICATE SOUTH WINDS BETWEEN
8 TO 13 KNOTS WITH SEA HEIGHTS NEAR 3 FEET ON THE GULF WATERS. A
WEAK PRESSURE GRADIENT ALONG THE LOWER TEXAS COAST WILL MAINTAIN
LIGHT TO MODERATE SOUTH TO SOUTHEAST WINDS AND LOW TO MODERATE
SEAS. HOWEVER...SMALL CRAFT WILL NEED TO EXERCISE CAUTION ON THE
LAGUNA MADRE THIS AFTERNOON DUE TO A SLIGHTLY STRONGER WINDS.
FRIDAY NIGHT THROUGH WEDNESDAY...LIGHT TO MODERATE WINDS AND LOW
TO MODERATE SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST THROUGH
EARLY NEXT WEEK AS A WEAK COLD FRONT PASSES THROUGH FRIDAY NIGHT
AND WEAK LOW PRESSURE PERSISTS AFTERWARDS. MARINE CONDITIONS NEAR
THE END OF THE FORECAST PERIOD ARE DEPENDENT ON THE DEVELOPMENT...
IF ANY...OF A WEAK AREA OF LOW PRESSURE OVER THE WESTERN GULF OF
MEXICO.
BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
64
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 243 PM CDT THU SEP 10 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD
FRONT STRETCHING FROM ABOUT IRON MOUNTAIN TO WAUSAU EARLY THIS
AFTERNOON. SHOWERS AND STORMS HAVE DEVELOPED ALONG IT OVER THE
UPPER PENINSULA...BUT ONLY A FEW BLIPS SHOWING UP ON RADAR OVER
NORTHERN WI SO FAR. SB CAPE HAS BEEN BUILDING AHEAD OF THE FRONT
AND THE HRRR/ARW CONTINUE TO DEVELOP SCT SHOWERS LATER THIS
AFTERNOON. ALTHOUGH BROUGHT DOWN PRECIP CHANCES SLIGHTLY THIS
AFTERNOON...DATA DOES NOT SUPPORT DROPPING THEM ENTIRELY. WILL KEEP
A SCATTERED MENTION MID-AFTERNOON INTO THE EARLY EVENING. BEHIND
THE FRONT...AN UPPER TROUGH IS DIGGING SOUTHWARD OVER ONTARIO AND
MINNESOTA...BRINGING WIDESPREAD CLOUDS AND SHOWERS WITH IT.
FORECAST CONCERNS INCLUDE PRECIP AND CLOUDS TRENDS.
TONIGHT...THE COLD FRONT WILL STALL OVER NORTHEAST WI FOR A PERIOD
THIS EVENING AS IT WAITS FOR A SHORTWAVE OVER NORTHERN MINNESOTA TO
ARRIVE. THEN THE SHORTWAVE WILL GIVE THE FRONT A PUSH TO THE SOUTH
LATE OVERNIGHT. DUE TO THE SLOW DEPARTURE OF THE FRONT...WILL KEEP
A SMALL CHANCE OF A SHOWER OVER NE WI UNTIL LATE TONIGHT.
OTHERWISE...THE SHORTWAVE WILL BRING AN INFLUX OF LOW STRATUS
SOUTHEAST FROM NORTHERN MINNESOTA AND WESTERN ONTARIO. 850MB TEMPS
WILL FALL TO AROUND +1C OVER WESTERN LAKE SUPERIOR...WHICH WILL
CREATE DELTA T/S OF AROUND 14C...SUFFICIENT OF LAKE EFFECT RAIN
SHOWERS TO DEVELOP. THEREFORE...AFTER A DRY START TO THE
EVENING....NORTH-CENTRAL WISCONSIN SHOULD SEE CLOUDS INCREASE AND
SHOWERS MOVE IN AFTER MIDNIGHT. LOWS TO FALL INTO THE MID 40S NORTH
TO LOW 50S SOUTH.
FRIDAY...THE UPPER TROUGH WILL MOVE OVERHEAD...BRINGING A COOL AND
CLOUDY AIRMASS WITH IT. THE MAIN VORT MAX WILL BE EXITING NORTHEAST
WISCONSIN AROUND MIDDAY...WHICH IS PERHAPS A REASON WHY MODELS ARE
UNENTHUSIASTIC ABOUT PRECIP CHANCES. HOWEVER...MODELS PROJECT A
NEARLY SATURATED LAYER UP TO ABOUT 700MB WITH STEEP LOW LEVEL LAPSE
RATES IN THE BL. SO THEREFORE THINK WILL SEE SCT LIGHT SHOWER
DEVELOP ACROSS MUCH OF THE AREA BY LATE MORNING AND PEAKING AROUND
EARLY AFTERNOON. SOME DRIER AIR MOVING IN FROM THE NORTH MAY CAUSE
SHOWERS TO DIMINISH THERE FIRST...AWAY FROM THE LAKE EFFECT BELTS.
WITH PLENTY OF CLOUDS...HIGHS TO ONLY REACH FROM THE MID 50S NORTH
TO LOW 60S SOUTH.
.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 243 PM CDT THU SEP 10 2015
HIGH PRESSURE WILL BUILD IN ACROSS THE WESTERN GREAT LAKES DURING
THE WEEKEND...DRYING OUT THE WEATHER OVER NORTHEAST WISCONSIN.
HOWEVER IN ADDITION TO DRY WEATHER THE HIGH WILL BRING COOL
TEMPERATURES AS 850 MB TEMPERATURES FALL INTO THE SINGLE DIGITS
ABOVE ZERO. AS THE HIGH BUILDS IN...CLOUDS WILL CLEAR OUT AND
SURFACE WINDS WILL BECOME LIGHT...MAKING FOR IDEAL RADIATIVE
COOLING CONDITIONS. THIS WILL LIKELY PRODUCE AREAS OF FROST ON
FRIDAY NIGHT ACROSS NORTH CENTRAL WISCONSIN...WITH PATCHY FROST
ACROSS THE SAME AREA SATURDAY NIGHT. OF THESE TWO NIGHTS IT LOOKS
LIKE FRIDAY NIGHT WILL BE THE COOLER OF THE TWO NIGHTS...WITH AN
ADVISORY BEING A POSSIBILITY AS LOWS DROP INTO THE MIDDLE 30S.
THERE WILL BE SOME RETURN FLOW SATURDAY NIGHT WITH SLIGHTLY WARMER
TEMPERATURES AS LOWS ONLY DROP TO AROUND 40 DEGREES. HIGHS THIS
WEEKEND WILL BE SEVERAL DEGREES BELOW NORMAL...WITH TEMPERATURES
ONLY EXPECTED TO GET INTO THE 60S.
RETURN FLOW ON THE BACKSIDE OF THE HIGH WILL ALLOW DAYTIME
TEMPERATURES TO REBOUND BACK INTO THE 70S...CLOSE TO NORMAL FOR
THIS TIME OF YEAR...DURING THE EARLY PART OF NEXT WEEK AS THE
HIGH CONTINUES TO PROVIDE DRY WEATHER ACROSS THE WESTERN GREAT
LAKES REGION.
THE NEXT CHANCE FOR RAIN WILL NOT OCCUR UNTIL WEDNESDAY AND
THURSDAY AS A LOW PRESSURE SYSTEM DEVELOPS ACROSS THE PLAINS AND
HEADS EAST THROUGH THE GREAT LAKES REGION. WITH THE HIGH IN PLACE
ACROSS THE EAST FEEDING IN DRY AIR IT WILL MAKE THE EASTWARD
PROGRESS OF THE LOW RATHER SLOW. WITH THIS IN MIND IT APPEARS THE
SLOWER ECMWF SOLUTION IS PREFERRED TO THE QUICKER GFS MODEL. HIGHS
DURING THIS PERIOD AHEAD OF THE COLD FRONT SHOULD STAY IN THE 70S
ACROSS NORTHEAST WISCONSIN.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1148 AM CDT THU SEP 10 2015
THERE WILL BE A CHANCE OF SHOWERS OVER EASTERN WISCONSIN THIS
AFTERNOON AND EVENING AS A COLD FRONT MOVES THROUGH THE AREA. CIGS
REMAIN ALL OVER THE PLACE SO FAR THIS MORNING...BUT WILL SHOW A RISE
TO VFR THIS AFTERNOON AS SOME OF THE LOWER CIGS MIX OUT. PARTIAL
CLEARING IS ANTICIPATED BEHIND THE FRONT...MAINLY OVER CENTRAL AND
NORTH-CENTRAL WI LATE THIS AFTERNOON AND INTO THIS EVENING. THEN
MVFR CLOUDS ARE EXPECTED TO SURGE SOUTHWARD OVERNIGHT ASSOCIATED
WITH AN UPPER LOW. SCT RAIN SHOWERS WILL BE POSSIBLE AT RHI...BUT
THE REST OF THE TAF SITES SHOULD SEE CHANCES FOR SHOWERS INCREASE BY
MID MORNING ON FRIDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......KURIMSKI
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
145 PM MDT THU SEP 10 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 230 PM MDT THU SEP 10 2015
TONIGHT...WEAK COLD FRONT WILL RESIDE ACROSS OUR EASTERN COUNTIES
THROUGH EARLY THIS EVENING AND WE MAY SEE ISOLATED TO WIDELY
SCATTERED EVENING SHOWERS AND THUNDERSTORMS ALONG THE COLD FRONT
OVER FAR EASTERN WYOMING AND WESTERN NEBRASKA. EXPECTING THE
PRECIPITATION TO END BY OR SHORTLY AFTER MIDNIGHT. BOUNDARY LAYER
FROM THE NAM SUGGESTING POSSIBLE AREAS OF FOG LATE TONIGHT FROM THE
INTERSTATE 80 SUMMIT EAST ACROSS CHEYENNE TO SIDNEY NEBRASKA.
FRIDAY...COOLER DAY WITH MORE CLOUD COVER AND IN THE WAKE OF THE
PASSING COLD FRONT. ALTHOUGH A LOW AND MID LEVEL THETA-E RIDGE AXIS
WILL LIE ACROSS SOUTHEAST WYOMING IN THE AFTERNOON...WITH MINIMAL
LIFT AND STABLE LOW LEVELS...NO PRECIPITATION EXPECTED.
FRIDAY NIGHT/SATURDAY/SATURDAY NIGHT...DECENT WARMING TREND ON TAP
FOR SATURDAY AS HEIGHTS ALOFT AND THICKNESSES RISE AS THE COOLER
AIRMASS MODERATES. WITH LIMITED LOW AND MID LEVEL MOISTURE AND
LIFT...NO PRECIPITATION ON TAP. NOT AS COOL SATURDAY NIGHT AS
SURFACE LEE TROUGHING INCREASES MIXING AND AS THE AIRMASS CONTINUES
TO SLOWLY MODERATE.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 230 PM MDT THU SEP 10 2015
FIRE WEATHER CONCERNS RETURN SUNDAY AS A SURFACE LOW PRESSURE
SYSTEM TRACKS THROUGH MONTANA. GFS 700MB WINDS INCREASING TO
20-25KTS ACROSS OUR WESTERN ZONES WITH AFTERNOON HUMIDITIES
RANGING FRO 7 TO 12 PERCENT ACROSS MUCH OF THE AREA. LIKELY
LOOKING AT RED FLAG CONDITIONS FOR MOST IF NOT OF OUR FIRE ZONES
SUNDAY. THESE WINDY CONDITIONS LIKELY TO CONTINUE INTO MONDAY.
STILL CONCERNS ON WHAT A PACIFIC LOW PRESSURE SYSTEM IS GOING TO
DO TOWARDS MID WEEK. SEEMS TO BE COMING MORE INTO AGREEMENT THAT
THE UPPER LOW WILL PASS NORTH OF WYOMING ACROSS MONTANA. GUIDANCE
SHOWING 700MB WINDS REALLY RAMPING UP MONDAY NIGHT INTO TUESDAY
WITH 45-50KTS FORECAST. CRAIG TO CASPER 700MB GRADIENTS IN EXCESS
OF 60MTRS. WE COULD BE DEALING WITH THE SEASONS FIRST HIGH WIND
EVENT...ESPECIALLY FOR OUR WIND PRONE AREAS. WILL CONTINUE TO
MONITOR THIS AS THE EVENT DRAWS CLOSER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1116 AM MDT THU SEP 10 2015
WEAK COLD FRONT HAS MADE IT THROUGH CHEYENNE LATE THIS MORNING AND
CONTINUES TO PUSH SOUTHWEST. THIS WILL SET UP AN UPSLOPING
EASTERLY WIND FOR AREAS EAST OF THE LARAMIE RANGE. LATEST SREF
GUIDANCE SHOWING LOWERING CONDITIONS IN FOG/STRATUS FOR THE
SOUTHERN PANHANDLE AND POSSIBLY KCYS BY EARLY FRIDAY MORNING. HAVE
STARTED THE TREND DOWN IN TAFS. HOPEFULLY...WE START SEEING THE
LOWERING TREND IN HRRR GUIDANCE TO BOLSTER CONFIDENCE AND FURTHER
NAIL DOWN TIMING/LOCATIONS.
&&
.FIRE WEATHER...
ISSUED AT 230 PM MDT THU SEP 10 2015
NEAR CRITICAL WINDS AND LOW HUMIDITIES BEING OBSERVED ACROSS
CARBON COUNTY THIS AFTERNOON. STILL BELIEVE THIS WILL BE SHORT
LIVED AS A COLD FRONT PUSHES SOUTH INTO THE AREA. ADDED CLOUDS
SHOULD HELP EASE MIXING DOWN OF WINDS AS WELL. HUMIDITIES AND
WINDS WILL REMAIN BELOW THRESHOLDS FRIDAY AND SATURDAY...THUS
MINIMAL CONCERNS. HOWEVER...ON SUNDAY AND MONDAY...HUMIDITIES AND
WINDS WILL BE APPROACHING CRITICAL THRESHOLDS SO FIRE WEATHER
CONCERNS WILL INCREASE AGAIN.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RUBIN
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1119 AM MDT THU SEP 10 2015
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 300 AM MDT THU SEP 10 2015
PRETTY QUIET WEATHER WILL CONTINUE LATE THIS WEEK AND INTO THE
WEEKEND WITH NORTHWEST FLOW ALOFT DOMINATING ACROSS THE FRONT
RANGE AND GREAT PLAINS. THE ONLY MINOR FORECAST CONCERN IS A WEAK
COLD FRONT AND ASSOCIATED UPPER LEVEL TROUGH. CURRENT OBS AND IR
SATELLITE LOOP SHOWS THE SLOW MOVING FRONT STILL NORTH OF THE AREA
ACROSS MONTANA. THIS FRONT IS FORECAST TO MOVE INTO NORTHERN
WYOMING EARLY THIS MORNING...AND EVENTUALLY ACROSS SOUTHEAST
WYOMING BY EARLY THIS AFTERNOON. WINDS WILL SHIFT INTO THE NORTH
AND NORTHEAST THIS AFTERNOON WITH SOME SLIGHTLY COOLER AIR MOVING
OVER THE HIGH PLAINS...MAINLY EAST OF THE LARAMIE RANGE. LOW AND
UPPER LEVEL DYNAMICS APPEAR UNFAVORABLE FOR PRECIPITATION AT THIS
TIME...SO KEPT A 20 PERCENT CHANCE OF SHOWERS MAINLY ACROSS
WESTERN NEBRASKA DUE TO SOME MARGINAL INSTABILITY AND WEAK UPPER
LEVEL DIFLUENCE AS A JET MAX AT 250MB BRUSHES OUR FAR EASTERN
ZONES THROUGH FRIDAY. CAN NOT RULE OUT SOME PATCHY FOG ALONG AND
NEAR THE LARAMIE RANGE EARLY FRIDAY MORNING AS WELL DUE TO MOIST
UPSLOPE FLOW AND COOL TEMPERATURES. TEMPERATURES ON FRIDAY ARE
EXPECTED TO BE SLIGHTLY BELOW NORMAL FOR THIS TIME OF THE YEAR AND
GENERALLY IN THE UPPER 60S TO MID 70S.
UPPER LEVEL RIDGE AXIS WILL BUILD BACK INTO THE FORECAST AREA FOR
SATURDAY WITH HIGH TEMPERATURES RETURNING TO THE 80S ACROSS MOST
OF THE FORECAST AREA. DRY CONDITIONS WILL CONTINUE OVER WYOMING
AND WESTERN NEBRASKA.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 315 AM MDT THU SEP 10 2015
WARM AND DRY LATE THIS WEEKEND INTO EARLY NEXT WEEK AS NORTHWEST
FLOW ALOFT FLATTENS OUT. HIGH TEMPERATURES WILL RUN ABOUT 10
DEGREE ABOVE THE SEASONAL NORMALS FOR MID SEPTEMBER WITH HIGHS
GENERALLY FROM THE MID 70S WEST TO MID 80S EAST. FORECAST
UNCERTAINTY CREEPS IN LATE IN THE FORECAST PERIOD. EXTENDED MODELS
DISAGREE TO THE EXTENT THAT A TROUGH WILL DIG ACROSS THE WESTERN
CONUS. 00Z GFS IS MORE AGGRESSIVE THAN THE ECMWF WITH SHORTWAVE
ENERGY ROUNDING THE BASE OF THE UPPER LEVEL OVER WYOMING ON
TUESDAY. THE GFS SOLUTION WOULD BRING SCATTERED SHOWERS AND
THUNDERSTORMS TO THE AREA TUESDAY INTO TUESDAY NIGHT ALONG WITH
COOLER TEMPERATURES...ESPECIALLY BY WEDNESDAY. THE ECMWF KEEPS THE
SHORTWAVE ENERGY WELL NORTH OF THE FORECAST AREA WITH THE UPPER
TROUGH AXIS WELL OFF TO THE WEST. NOT BITING ON ANY SOLUTION AT
THIS POINT BUT LEANING TOWARD THE EC. WILL WATCH MODEL TRENDS THE
NEXT FEW DAYS. REGARDLESS IT WILL MAINLY BE DRY THROUGH THE
EXTENDED FORECAST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1116 AM MDT THU SEP 10 2015
WEAK COLD FRONT HAS MADE IT THROUGH CHEYENNE LATE THIS MORNING AND
CONTINUES TO PUSH SOUTHWEST. THIS WILL SET UP AN UPSLOPING
EASTERLY WIND FOR AREAS EAST OF THE LARAMIE RANGE. LATEST SREF
GUIDANCE SHOWING LOWERING CONDITIONS IN FOG/STRATUS FOR THE
SOUTHERN PANHANDLE AND POSSIBLY KCYS BY EARLY FRIDAY MORNING. HAVE
STARTED THE TREND DOWN IN TAFS. HOPEFULLY...WE START SEEING THE
LOWERING TREND IN HRRR GUIDANCE TO BOLSTER CONFIDENCE AND FURTHER
NAIL DOWN TIMING/LOCATIONS.
&&
.FIRE WEATHER...
ISSUED AT 231 AM MDT THU SEP 10 2015
ELEVATED FIRE WEATHER CONCERNS THIS AFTERNOON FOR LOCATIONS WEST
OF THE LARAMIE RANGE. WINDS ARE EXPECTED TO BE WEAKER COMPARED TO
THE LAST FEW DAYS AS A COLD FRONT MOVES SOUTHWARD ACROSS EASTERN
WYOMING. THIS FRONT WILL RESULT IN WINDS SHIFTING INTO THE NORTH
OR NORTHEAST AT THE SURFACE...WHILE INCREASING RELATIVE HUMIDITIES
BY 5 PERCENT BY LATE THIS AFTERNOON DUE TO THE SLIGHTLY COOLER
AIRMASS. STILL...A FEW LOCATIONS ACROSS CARBON AND ALBANY COUNTIES
MAY SEE RED FLAG CRITERIA BRIEFLY EARLY THIS AFTERNOON EVEN THOUGH
COVERAGE WILL BE LIMITED. AFTER A FEW DAYS OF LIGHT WINDS AND
SOMEWHAT HIGHER HUMIDITIES...CRITICAL FIRE WEATHER CONDITIONS MAY
RETURN BY SUNDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...TJT
LONG TERM...SML
AVIATION...GCC
FIRE WEATHER...TJT