Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/28/14
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
312 PM MST FRI SEP 26 2014
.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS.
&&
...SEVERE WEATHER THREAT OVER SOUTH-CENTRAL ARIZONA FROM LATE
MORNING INTO THE EVENING HOURS ON SATURDAY...
.SYNOPSIS...
A STRONG PACIFIC STORM IS FORECAST TO MOVE INTO...AND ACROSS THE
DESERT SOUTHWEST FROM LATE TODAY INTO THE WEEKEND. THIS
STORM...COMBINED WITH AMPLE LEFTOVER MONSOON MOISTURE...IS EXPECTED
TO PRODUCE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE
REGION. SOME OF THE STRONGER STORMS WILL BE CAPABLE OF PRODUCING
LOCALLY STRONG...EVEN DAMAGING WINDS...HEAVY RAIN...AND HAIL. AFTER
A COLD FRONTAL PASSAGE SATURDAY NIGHT...DRIER WEATHER WITH BELOW
NORMAL TEMPERATURES ARE FORECAST TO SPREAD EASTWARD OVER THE REGION
FROM SUNDAY THROUGH THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...
TONIGHT AND SATURDAY...
AFTER A QUIET MORNING...THE COMBINATION OF A VERY MOIST AIRMASS FOR
LATE SEPTEMBER...PWATS IN THE 1.50-1.80 INCH RANGE...SOLAR
HEATING...AND A WEAK DISTURBANCE MOVING NORTHWARD FROM NORTHERN
MEXICO...IS NOW BEGINNING TO TRIGGER SCATTERED THUNDERSTORMS ACROSS
PIMA COUNTY...WITH SOME CELLS MOVING NORTHWARD INTO SW MARICOPA
COUNTY THIS HOUR. THE LATEST RUN OF THE HRRR HI-RES MODEL IS NOW
MOVING SCATTERED THUNDERSTORMS ACROSS MARICOPA COUNTY THROUGH THE
REST OF THIS AFTERNOON AND EARLY EVENING...WITH ACTIVITY DIMINISHING
AFTER SUNSET. THE MAIN IMPACT WILL BE LOCALLY HEAVY RAIN...GUSTY
WINDS...AND BLOWING DUST.
THE MAIN EVENT...WHICH IS A STRONG PACIFIC LOW CENTER...IS STILL
EXPECTED TO BEGIN TO IMPACT OUR CWA BEGINNING LATE TONIGHT...THEN
CONTINUE INTO EARLY SUNDAY. THE COMBINATION OF A VERY RICH MOISTURE
ENVIRONMENT AND STRONG VERTICAL WIND SHEAR THROUGH THE COLUMN...WITH
SFC-6KM BULK SHEAR VALUES OF UP TO 50KTS IS EXPECTED TO GENERATE
WIDESPREAD THUNDERSTORM ACTIVITY ACROSS THE WESTERN PORTION OF OUR
CWA LATE TONIGHT...MAINLY ACROSS THE CO RIVER VALLEY AND OVER LA PAZ
COUNTY. THE MAIN ISSUE WITH THESE STORMS WILL AGAIN BE HEAVY RAIN
AND GUST WINDS...AND LOCAL FLOODING.
DEVELOPING STORM DYNAMICS...WITH INCREASING MONSOON MOISTURE ARE
THEN EXPECTED TO BE STRONGEST OVER SOUTH CENTRAL AZ...INCLUDING
PHOENIX...FROM LATE MORNING THROUGH THE MID-EVENING HOURS ON
SATURDAY...WITH THE STORM PREDICTION CENTER KEEPING SOUTH-CENTRAL AZ
IN A SLIGHT RISK AREA FOR SEVERE THUNDERSTORMS. AGAIN...THE
COMBINATION OF FAVORABLE DIFLUENT FLOW...SFC-6KM BULK SHEAR VALUES
AS HIGH AS 50KTS...AND FAVORABLE TIME-OF-DAY...DURING THE AFTERNOON
HOURS...IS EXPECTED TO MAXIMIZE THE POTENTIAL FOR ORGANIZED SEVERE
STORM ACTIVITY. THE MAIN THREATS WILL BE HEAVY RAIN AND LARGE HAIL.
ALTHOUGH AN ISOLATED TORNADO IS POSSIBLE WITH THE STRONGEST
CONVECTION...THERE IS NOT A GREAT DEAL OF DIRECTIONAL SHEAR THROUGH
THE COLUMN...WHICH SHOULD MINIMIZE THE TORNADO THREAT...WITH LARGE
HAIL AND DAMAGING WINDS BEING THE MAIN THREATS.
SOME COMPARISONS HAVE ALREADY BEEN MADE BETWEEN THIS UPCOMING EVENT
AND THE ONE THAT OCCURRED BACK ON 05 OCT 2010...WHICH BROUGHT SEVERE
HAIL...UP TO 3 INCHES IN DIAMETER...HEAVY RAIN AND STRONG WINDS TO
THE GREATER PHOENIX AREA. ALTHOUGH THE OVERALL UPPER AIR PATTERNS
APPEAR TO BE SIMILAR FOR BOTH EVENTS...THE OCT 2010 EVENT HAD COLDER
AIR AT THE MID-LEVELS TO WORK WITH...500MB TEMPS DURING THAT EVENT
WERE AROUND -14C...WHILE 500MB TEMPS ON SATURDAY ARE EXPECTED TO BE
AROUND -9C. THE PARENT UPPER LOW CENTER DURING THE 2010 EVENT ALSO
TRACKED A BIT FURTHER TO THE SOUTH...FROM PALMDALE CA TO LAS
VEGAS...THEN INTO SOUTH-CENTRAL UT. THIS EVENT IS TAKING THE UPPER
LOW CENTER FROM THE SFO BAY AREA ESE-WARD ACROSS SOUTH-CENTRAL
NV...THEN INTO SOUTHERN UT. ON THE OTHER HAND...SATURDAY/S EVENT
LOOKS LIKE IT WILL HAVE MORE AVAILABLE MOISTURE...WITH PWATS IN THE
1.50-1.75 INCH RANGE...AS COMPARED TO AMOUNTS IN THE 1.25-1.50 INCH
DURING THE 2010 EVENT.
SHOWER/THUNDERSTORM ACTIVITY IS THEN EXPECTED TO RAPIDLY DIMINISH
SATURDAY NIGHT ACROSS THE LOWER DESERTS OF SOUTH-CENTRAL ARIZONA AS
THE SFC FRONT PASSES THOUGH AND DRIER AIR WORKS ITS WAY IN FROM THE
WEST. ISOLATED TO SCATTERED SHOWER ACTIVITY WILL LIKELY LINGER INTO
SUNDAY OVER THE HIGHER TERRAIN OF SOUTHERN GILA COUNTY DUE TO LOCAL
UPSLOPE FLOW AND ANOTHER WEAK DISTURBANCE MOVING THROUGH THE REGION.
MONDAY THROUGH THURSDAY...
DRY WEATHER WITH NEAR...TO SLIGHTLY BELOW SEASONAL TEMPERATURES ARE
EXPECTED ACROSS THE ENTIRE FORECAST AREA.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...AND
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
EXPECT SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE AREA THIS
AFTERNOON/EVENING UNTIL AROUND 03Z...WITH SCT-BKN CLOUD DECKS
GENERALLY AOA 7000FT PERSISTING OVERNIGHT INTO SATURDAY. LOCAL CIGS
MAY DROP TO 6000FT WITH STRONGER CELLS...AND VISIBILITY BRIEFLY
LOWER TO 2SM IN HEAVY RAIN OR BLDU. SHEAR PROFILES ALOFT ALSO
SUPPORT AN ORGANIZED/SEVERE THUNDERSTORM ENVIRONMENT...ESPECIALLY
NEAR KBLH...HOWEVER ISOLD STORMS COULD IMPACT ALL TERMINALS AT SOME
TIME THROUGH SATURDAY AFTERNOON...WITH SURFACE WIND GUSTS UP TO 55KT
POSSIBLE ALONG WITH HAIL. LIGHTER WINDS ANTICIPATED OVERNIGHT...
BUT WITH A LINGERING/REMOTE THREAT FOR SHOWERS. LATE SATURDAY
MORNING...SURFACE WINDS ONCE AGAIN INCREASE AFTER 15Z WITH THE
PASSAGE OF A COLD FRONT...ALONG WITH THE AREA-WIDE THUNDERSTORM
POTENTIAL.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
DRIER AIR WILL BEGIN MOVING INTO THE AREA ON MONDAY...WITH LITTLE TO
NO CHANCE OF CONVECTION THE REMAINING PORTION OF THE FORECAST
PERIOD. MINIMUM HUMIDITY LEVELS WILL TREND DOWN TO AROUND 15 PERCENT
BY THURSDAY. IN ADDITION TO THE DRIER AIR...COOLER TEMPERATURES ARE
EXPECTED THE ENTIRE PERIOD. SOME GUSTY WEST TO SOUTHWEST WINDS ARE
POSSIBLE ALONG AND BEHIND THE TROUGH EARLY SUNDAY...ALTHOUGH WIND
SPEEDS WILL BE GENERALLY LIGHT AND FOLLOW TYPICAL DIURNAL PATTERNS
MONDAY THROUGH THURSDAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
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DISCUSSION...PERCHA
AVIATION...MEYERS
FIRE WEATHER...MEYERS/MCLANE
AREA FORECAST DISCUSSION
NWS TUCSON AZ
310 PM MST FRI SEP 26 2014
.SYNOPSIS...A STRONG STORM SYSTEM OVER THE GREAT BASIN WILL BRING A
GOOD CHANCE OF SHOWERS AND THUNDERSTORMS ON SATURDAY. THE STRONGER
THUNDERSTORMS WILL BE CAPABLE OF PRODUCING DAMAGING WINDS...HAIL...
AND HEAVY RAINFALL. RAIN CHANCES WILL DECREASE FROM WEST TO EAST
SATURDAY NIGHT THROUGH MONDAY FOLLOWED BY DRY CONDITIONS TUESDAY
THROUGH FRIDAY.
&&
.DISCUSSION...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WERE
ONGOING WEST TO SOUTH OF TUCSON...ESPECIALLY ACROSS THE TOHONO
O`ODHAM NATION SEWD INTO SANTA CRUZ COUNTY. MEANWHILE...MOSTLY SUNNY
SKIES WERE OBSERVED ACROSS FAR WRN PIMA COUNTY. ELSEWHERE...
SCATTERED SHOWERS/TSTMS WERE OCCURRING ACROSS THE WHITE MOUNTAINS NE
OF SAFFORD. GIVEN THE VERY SLOW STORM MOVEMENTS...HAVE TO AGREE WITH
THE 20Z RUC HRRR DEPICTION OF CONTINUED SHOWERS/TSTMS MOSTLY WEST-
TO-SOUTH OF TUCSON DURING THE NEXT SEVERAL HOURS.
THERE REMAINS CONSIDERABLE UNCERTAINTY REGARDING ANY RAINFALL OF
SIGNIFICANCE ACROSS THE TUCSON METRO AREA INTO THIS EVENING. FOR
NOW...HAVE MAINTAINED A 30 PERCENT CHANCE OF SHOWERS/TSTMS FOR
TUCSON THIS EVENING FOLLOWED BY SIGNIFICANTLY REDUCED POPS LATE
TONIGHT. THE BULK OF SHOWERS/TSTMS IS PROGGED TO END ACROSS THE AREA
BY AROUND MIDNIGHT. HOWEVER...HAVE CONTINUED A SLIGHT CHANCE OF
SHOWERS/TSTMS ESSENTIALLY FROM TUCSON WWD/NWD LATE TONIGHT.
THE FOCUS OF ATTENTION THEN SHIFTS TOWARD THE UPPER TROUGH/CLOSED
LOW PROGGED TO MOVE EWD INTO THE GREAT BASIN/SWRN CONUS SAT. AMPLE
MOISTURE IN COMBINATION WITH INCREASING DIFFLUENCE ALOFT SHOULD
PRODUCE SCATTERED TO NUMEROUS SHOWERS/TSTMS...ESPECIALLY SAT
AFTERNOON/EVENING. THE POTENTIAL FOR SEVERE TSTMS EXISTS ESPECIALLY
ACROSS NRN/CENTRAL AZ. HOWEVER...WOULD NOT BE SURPRISED TO SEE A
SEVERE THUNDERSTORM WATCH ISSUED PERHAPS AS FAR SOUTH AS PINAL
COUNTY...WITH A LESSER CHANCE OF A SEVERE THUNDERSTORM WATCH
ISSUANCE AS FAR EAST AS GRAHAM/GREENLEE COUNTIES.
GIVEN THE AVAILABLE MOISTURE...HEAVY RAINFALL WILL CERTAINLY BE A
POSSIBILITY WITH THE STRONGER THUNDERSTORMS. THE CLOSED UPPER LOW IS
PROGGED TO REMAIN QUASI-STATIONARY OVER NEVADA SAT NIGHT-SUN. THERE
IS A CHANCE OF SHOWERS/TSTMS ACROSS ERN SECTIONS SUN...AND A SLIGHT
CHANCE OF SHOWERS/TSTMS FOR THE TUCSON METRO AREA. DRY CONDITIONS
WILL PREVAIL SUN ACROSS WRN PIMA COUNTY.
THE UPPER LOW IS PROGGED TO OPEN OVER UTAH/IDAHO MON MORNING AND
EJECT EWD INTO THE NRN ROCKIES MON NIGHT. THE BULK OF SHOWERS/TSTMS
WILL TAPER FROM WEST TO EAST SUN NIGHT FOLLOWED BY A SLIGHT CHANCE
OF SHOWERS/TSTMS MAINLY NEAR THE MOUNTAINS OF GREENLEE/GRAHAM/
COCHISE COUNTIES MON. DRY CONDITIONS WILL THEN PREVAIL MON NIGHT-FRI
UNDER WLY/NWLY FLOW ALOFT.
A COOLING TREND WILL OCCUR THIS WEEKEND FOLLOWED BY WARMER DAYTIME
TEMPS BY THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...VALID THRU 28/00Z.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR THROUGH
SATURDAY AFTERNOON. EXPECT MVFR CONDITIONS AND WIND GUSTS OF 50-55
KTS WITH THE STRONGEST THUNDERSTORMS. OTHERWISE...CLOUD DECKS WILL
GENERALLY BE AT 4-10K FT AGL. SURFACE WIND WILL GENERALLY BE LESS
THAN 10 KTS THRU TONIGHT...THEN SURFACE WIND SATURDAY WILL BE SLY/
SWLY 12-18 KTS WITH GUSTS TO 25 KTS. AVIATION DISCUSSION NOT UPDATED
FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...SCATTERED TO NUMEROUS THUNDERSTORMS...SOME CAPABLE
OF PRODUCING STRONG WINDS AND HAIL...WILL OCCUR SATURDAY. RAIN
CHANCES WILL DECREASE FROM WEST TO EAST SATURDAY NIGHT AND SUNDAY
FOLLOWED BY DRY CONDITIONS AREA WIDE DURING THE UPCOMING WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
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FRANCIS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
300 PM MST FRI SEP 26 2014
...SEVERE WEATHER THREAT OVER SOUTH-CENTRAL ARIZONA FROM LATE
MORNING INTO THE EVENING HOURS ON SATURDAY...
.SYNOPSIS...
A STRONG PACIFIC STORM IS FORECAST TO MOVE INTO...AND ACROSS THE
DESERT SOUTHWEST FROM LATE TODAY INTO THE WEEKEND. THIS
STORM...COMBINED WITH AMPLE LEFTOVER MONSOON MOISTURE...IS EXPECTED
TO PRODUCE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE
REGION. SOME OF THE STRONGER STORMS WILL BE CAPABLE OF PRODUCING
LOCALLY STRONG...EVEN DAMAGING WINDS...HEAVY RAIN...AND HAIL. AFTER
A COLD FRONTAL PASSAGE SATURDAY NIGHT...DRIER WEATHER WITH BELOW
NORMAL TEMPERATURES ARE FORECAST TO SPREAD EASTWARD OVER THE REGION
FROM SUNDAY THROUGH THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...
TONIGHT AND SATURDAY...
AFTER A QUIET MORNING...THE COMBINATION OF A VERY MOIST AIRMASS FOR
LATE SEPTEMBER...PWATS IN THE 1.50-1.80 INCH RANGE...SOLAR
HEATING...AND A WEAK DISTURBANCE MOVING NORTHWARD FROM NORTHERN
MEXICO...IS NOW BEGINNING TO TRIGGER SCATTERED THUNDERSTORMS ACROSS
PIMA COUNTY...WITH SOME CELLS MOVING NORTHWARD INTO SW MARICOPA
COUNTY THIS HOUR. THE LATEST RUN OF THE HRRR HI-RES MODEL IS NOW
MOVING SCATTERED THUNDERSTORMS ACROSS MARICOPA COUNTY THROUGH THE
REST OF THIS AFTERNOON AND EARLY EVENING...WITH ACTIVITY DIMINISHING
AFTER SUNSET. THE MAIN IMPACT WILL BE LOCALLY HEAVY RAIN...GUSTY
WINDS...AND BLOWING DUST.
THE MAIN EVENT...WHICH IS A STRONG PACIFIC LOW CENTER...IS STILL
EXPECTED TO BEGIN TO IMPACT OUR CWA BEGINNING LATE TONIGHT...THEN
CONTINUE INTO EARLY SUNDAY. THE COMBINATION OF A VERY RICH MOISTURE
ENVIRONMENT AND STRONG VERTICAL WIND SHEAR THROUGH THE COLUMN...WITH
SFC-6KM BULK SHEAR VALUES OF UP TO 50KTS IS EXPECTED TO GENERATE
WIDESPREAD THUNDERSTORM ACTIVITY ACROSS THE WESTERN PORTION OF OUR
CWA LATE TONIGHT...MAINLY ACROSS THE CO RIVER VALLEY AND OVER LA PAZ
COUNTY. THE MAIN ISSUE WITH THESE STORMS WILL AGAIN BE HEAVY RAIN
AND GUST WINDS...AND LOCAL FLOODING.
DEVELOPING STORM DYNAMICS...WITH INCREASING MONSOON MOISTURE ARE
THEN EXPECTED TO BE STRONGEST OVER SOUTH CENTRAL AZ...INCLUDING
PHOENIX...FROM LATE MORNING THROUGH THE MID-EVENING HOURS ON
SATURDAY...WITH THE STORM PREDICTION CENTER KEEPING SOUTH-CENTRAL AZ
IN A SLIGHT RISK AREA FOR SEVERE THUNDERSTORMS. AGAIN...THE
COMBINATION OF FAVORABLE DIFLUENT FLOW...SFC-6KM BULK SHEAR VALUES
AS HIGH AS 50KTS...AND FAVORABLE TIME-OF-DAY...DURING THE AFTERNOON
HOURS...IS EXPECTED TO MAXIMIZE THE POTENTIAL FOR ORGANIZED SEVERE
STORM ACTIVITY. THE MAIN THREATS WILL BE HEAVY RAIN AND LARGE HAIL.
ALTHOUGH AN ISOLATED TORNADO IS POSSIBLE WITH THE STRONGEST
CONVECTION...THERE IS NOT A GREAT DEAL OF DIRECTIONAL SHEAR THROUGH
THE COLUMN...WHICH SHOULD MINIMIZE THE TORNADO THREAT...WITH LARGE
HAIL AND DAMAGING WINDS BEING THE MAIN THREATS.
SOME COMPARISONS HAVE ALREADY BEEN MADE BETWEEN THIS UPCOMING EVENT
AND THE ONE THAT OCCURRED BACK ON 05 OCT 2010...WHICH BROUGHT SEVERE
HAIL...UP TO 3 INCHES IN DIAMETER...HEAVY RAIN AND STRONG WINDS TO
THE GREATER PHOENIX AREA. ALTHOUGH THE OVERALL UPPER AIR PATTERNS
APPEAR TO BE SIMILAR FOR BOTH EVENTS...THE OCT 2010 EVENT HAD COLDER
AIR AT THE MID-LEVELS TO WORK WITH...500MB TEMPS DURING THAT EVENT
WERE AROUND -14C...WHILE 500MB TEMPS ON SATURDAY ARE EXPECTED TO BE
AROUND -9C. THE PARENT UPPER LOW CENTER DURING THE 2010 EVENT ALSO
TRACKED A BIT FURTHER TO THE SOUTH...FROM PALMDALE CA TO LAS
VEGAS...THEN INTO SOUTH-CENTRAL UT. THIS EVENT IS TAKING THE UPPER
LOW CENTER FROM THE SFO BAY AREA ESE-WARD ACROSS SOUTH-CENTRAL
NV...THEN INTO SOUTHERN UT. ON THE OTHER HAND...SATURDAY/S EVENT
LOOKS LIKE IT WILL HAVE MORE AVAILABLE MOISTURE...WITH PWATS IN THE
1.50-1.75 INCH RANGE...AS COMPARED TO AMOUNTS IN THE 1.25-1.50 INCH
DURING THE 2010 EVENT.
SHOWER/THUNDERSTORM ACTIVITY IS THEN EXPECTED TO RAPIDLY DIMINISH
SATURDAY NIGHT ACROSS THE LOWER DESERTS OF SOUTH-CENTRAL ARIZONA AS
THE SFC FRONT PASSES THOUGH AND DRIER AIR WORKS ITS WAY IN FROM THE
WEST. ISOLATED TO SCATTERED SHOWER ACTIVITY WILL LIKELY LINGER INTO
SUNDAY OVER THE HIGHER TERRAIN OF SOUTHERN GILA COUNTY DUE TO LOCAL
UPSLOPE FLOW AND ANOTHER WEAK DISTURBANCE MOVING THROUGH THE REGION.
MONDAY THROUGH THURSDAY...
DRY WEATHER WITH NEAR...TO SLIGHTLY BELOW SEASONAL TEMPERATURES ARE
EXPECTED ACROSS THE ENTIRE FORECAST AREA.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
INCREASED MOISTURE WILL LEAD TO EARLY TO MID AFTERNOON SHOWERS AND
THUNDERSTORMS OVER FAVORED HIGH TERRAIN AREAS. SOME OF THESE STORMS
SHOULD MAKE THEIR WAY INTO THE PHOENIX AREA EARLY THIS
EVENING...POSSIBLY AFFECTING AREA TERMINALS. A REMOTE THREAT FOR
SHOWERS WILL REMAIN THROUGH THE OVERNIGHT HOURS FRIDAY NIGHT AHEAD
OF AN APPROACHING COLD FRONT. WINDS WILL REMAIN LIGHT THROUGH THE
PERIOD WITH ONLY A SMALL WINDOW OF WESTERLY DIRECTIONAL FLOW MAINLY
LATE THIS AFTERNOON.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
WINDS WILL INCREASE THROUGH THE DAY TODAY WITH GUSTY WINDS EXPECTED
THIS AFTERNOON. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE
AS THE DAY PROGRESSES WITH THE BEST CHANCE GENERALLY BETWEEN 21Z-03Z
TODAY...AND FAVORING THE LOWER COLORADO RIVER VALLEY. SOME
THUNDERSTORMS TODAY MAY BE STRONG...POTENTIALLY PRODUCING STRONG
OUTFLOW WINDS. A SMALL CHANCE OF MAINLY SHOWERS WILL REMAIN THROUGH
THE OVERNIGHT HOURS TONIGHT AHEAD OF AN APPROACHING COLD FRONT THAT
IS EXPECTED TO SWEEP THROUGH THE AREA SOME TIME SATURDAY MORNING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
SHOWERS AND THUNDERSTORMS...MAINLY EAST OF PHOENIX...ARE POSSIBLE ON
SUNDAY AS AN UPPER LEVEL TROUGH LINGERS OVER THE REGION. DRIER AIR
WILL BEGIN MOVING INTO THE AREA ON MONDAY...WITH LITTLE TO NO CHANCE
OF CONVECTION THE REMAINING PORTION OF THE FORECAST PERIOD.
AFTERNOON MINIMUM HUMIDITY LEVELS WILL AVERAGE AROUND 20 PERCENT ON
SUNDAY...AND THEN TREND TO AROUND 15 PERCENT BY THURSDAY. IN
ADDITION TO THE DRIER AIR...COOLER TEMPERATURES ARE EXPECTED THE
ENTIRE PERIOD. SOME GUSTY WEST TO SOUTHWEST WINDS ARE POSSIBLE ALONG
AND BEHIND THE TROUGH ON SUNDAY...THOUGH WIND SPEEDS WILL BE
GENERALLY LIGHT AND FOLLOW TYPICAL DIURNAL PATTERNS MONDAY THROUGH
THURSDAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
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DISCUSSION...PERCHA
AVIATION...KUHLMAN
FIRE WEATHER...MCLANE
AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 AM MST FRI SEP 26 2014
.SYNOPSIS...THE CHANCE FOR SHOWERS AND THUNDERSTORMS WILL INCREASE
THROUGH SATURDAY AS A FRONT APPROACHES THE AREA FROM THE NORTHWEST.
THERE IS AN INCREASED RISK FOR STRONGER AND WETTER STORMS ON
SATURDAY. DRIER AND COOLER NEXT WEEK AS THE MONSOON SEASON COMES TO
A CLOSE.
&&
.DISCUSSION...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE
ONGOING ACROSS SRN GRAHAM/NRN COCHISE COUNTIES AT THIS TIME.
MEANWHILE...MOSTLY SUNNY SKIES WERE ACROSS WRN/CENTRAL PIMA COUNTY
WITH PARTLY CLOUDY TO MOSTLY CLOUDY SKIES ELSEWHERE. AMPLE MOISTURE
WAS ACROSS SE AZ WITH DEWPOINTS VALID 16Z GENERALLY IN THE LOWER-
MID 60S F. 26/12Z KTWC SOUNDING PRECIP WATER VALUE WAS 1.53 INCHES...
NEARLY ONE QUARTER OF AN INCH HIGHER VERSUS 24 HOURS AGO. THE
ENVIRONMENT WAS MODERATELY UNSTABLE...WITH LIFTED INDEX OF MINUS 5
AND UNMODIFIED SBCAPE OF 1830 J/KG. MID-LEVEL STEERING FLOW WILL
FAVOR GENERALLY SWWD STORM MOTIONS. 26/12Z UPPER AIR PLOTS DEPICTED
DEEP TROUGH ADJACENT THE WEST COAST...AND RIDGE AXIS EXTENDED FROM
SRN AZ NEWD INTO THE UPPER MISSISSIPPI RIVER VALLEY.
26/13Z RUC HRRR AND 26/12Z UNIV OF AZ WRF-NAM WERE SIMILAR WITH
DEPICTING A GENERAL DECREASE IN SHOWERS/TSTMS ACROSS ERN SECTIONS
DURING THE NEXT SEVERAL HOURS. HOWEVER...THESE SOLUTIONS WERE
SIMILAR WITH DEVELOPING FAIRLY STRONG SHOWERS/TSTMS TO OCCUR MOSTLY
WEST TO SOUTH OF TUCSON EARLY THIS AFTERNOON. THE RUC HRRR THEN
FAVORS WRN/CENTRAL PIMA COUNTY AS WELL AS GREENLEE COUNTY FOR
SHOWERS/TSTMS LATER THIS AFTERNOON AND THIS EVENING. THE INHERITED
POPS SEEM REASONABLE...ALTHOUGH MAY INCREASE VALUES ESPECIALLY
ACROSS WRN SECTIONS THIS AFTERNOON. A GENERAL DECREASE IN COVERAGE
OF SHOWERS/TSTMS SHOULD THEN OCCUR TONIGHT.
THE FOCUS OF ATTENTION THEN SHIFTS TOWARD THE UPPER TROUGH/CLOSED
LOW PROGGED TO MOVE EWD INTO THE GREAT BASIN/SWRN CONUS SAT. AMPLE
MOISTURE IN COMBINATION WITH INCREASING DIFFLUENCE ALOFT SHOULD
SCATTERED TO NUMEROUS SHOWERS/TSTMS ESPECIALLY SAT AFTERNOON/EVENING.
THE POTENTIAL FOR MORE WIDESPREAD SEVERE TSTMS WILL EXIST MAINLY
NORTH OF TUCSON. THE CLOSED UPPER LOW IS PROGGED TO REMAIN QUASI-
STATIONARY OVER NEVADA SAT NIGHT-SUN. THERE IS A CHANCE OF SHOWERS/
TSTMS ACROSS ERN SECTIONS SUN...AND A SLIGHT CHANCE OF SHOWERS/TSTMS
FOR THE TUCSON METRO AREA. DRY CONDITIONS WILL PREVAIL SUN ACROSS
WRN PIMA COUNTY.
THE UPPER LOW IS PROGGED TO OPEN SUN NIGHT AND EJECT EWD INTO THE
NRN ROCKIES MON. THE BULK OF SHOWERS/TSTMS WILL TAPER FROM WEST TO
EAST SUN NIGHT FOLLOWED BY A SLIGHT CHANCE OF SHOWERS/TSTMS MAINLY
NEAR THE MOUNTAINS OF GREENLEE/GRAHAM/COCHISE COUNTIES MON. DRY
CONDITIONS WILL THEN PREVAIL MON NIGHT-THUR UNDER WLY/NWLY FLOW
ALOFT.
HIGH TEMPS THIS AFTERNOON WILL BE NEARLY 2-5 DEGS F COOLER VERSUS
THUR. A COOLING TREND WILL THEN OCCUR THIS WEEKEND FOLLOWED BY
WARMER DAYTIME TEMPS BY THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...VALID THRU 27/12Z.
FEW-SCT CLOUDS AT 8-12K FT AGL THRU 26/19Z...MAINLY EAST OF A KFHU
TO KSAD LINE...OTHERWISE SKC CONDITIONS. SCT-BKN CLOUDS AT 6-10K FT
AGL DEVELOPING AFT 26/19Z AND PERSISTING TIL 27/05Z. DECREASING
CLOUDS EXPECTED AFT 27/05Z. ISOLATED TO SCATTERED SHRA/TSRA AFT
26/20Z...MAINLY IN THE HIGHER TERRAIN NORTHEAST OF KTUS...AND ALSO
SOUTH/SOUTHWEST OF KTUS. THE BULK OF THESE SHOWERS/THUNDERSTORMS
WILL END AROUND 27/04Z FOLLOWED BY ISOLATED -SHRA/-TSRA LATE
TONIGHT/SATURDAY MORNING. MORE NUMEROUS SHRA/TSRA COVERAGE IS THEN
EXPECTED SATURDAY AFTERNOON/EVENING. WIND GUSTS TO NEAR 45 KTS
POSSIBLE WITH THE STRONGER THUNDERSTORMS. OTHERWISE...SURFACE WIND
GENERALLY LESS THAN 10 KTS THRU 27/12Z. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...THERE WILL BE INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS TODAY AND SATURDAY ACROSS ALL OF SOUTHEAST ARIZONA...
WITH LINGERING PRECIPITATION CHANCES OVER THE EASTERN HALF OF THE
FORECAST AREA ON SUNDAY. MUCH DRIER CONDITIONS ARE THEN EXPECTED
NEXT WEEK AS THE 2014 MONSOON SEASON COMES TO AN END. THE STRONGER
THUNDERSTORMS MAY PRODUCE SOME GUSTY OUTFLOW WINDS. OTHERWISE...
20-FOOT WINDS WILL BE LESS THAN 15 MPH TODAY...AND SOUTHWEST AT 10
TO 20 MPH SATURDAY AND SUNDAY AFTERNOON.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
900 AM MST FRI SEP 26 2014
.SYNOPSIS...
A STRONG PACIFIC STORM IS FORECAST TO MOVE INTO THE WESTERN STATES
LATE TODAY INTO THE WEEKEND...WHICH WILL RESULT IN AN INCREASED
CHANCE OF SHOWERS AND THUNDERSTORMS. SOME OF THE STRONGER STORMS IN
SOUTH CENTRAL ARIZONA WILL BE CAPABLE OF PRODUCING LOCALLY GUSTY
WINDS...HEAVY RAIN...AND HAIL. AFTER A COLD FRONTAL PASSAGE SATURDAY
NIGHT...DRIER WEATHER WITH BELOW NORMAL TEMPERATURES ARE FORECAST
FROM LATE SUNDAY NIGHT THROUGH THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...
MOISTURE MOVING NORTH FROM MEXICO HAS BROUGHT A WARM...AND VERY
MUGGY MORNING TO OUR CWA TODAY...WITH SFC DEWPOINTS IN THE MID-UPPER
70S ACROSS SE CA AND SW AZ...AND DEWPOINTS IN THE UPPER 60S AND LOW
70S ACROSS SOUTH-CENTRAL AZ. THE LATEST GOES SOUNDER IMAGERY IS NOW
SHOWING PWATS HAVE RISEN IN THE 1.40-1.70 INCH RANGE ACROSS OUR CWA
AS WELL. THE UPPER LOW THAT WILL BE ACTING ON THIS COPIOUS MOISTURE
IS JUST ABOUT READY TO MOVE INLAND OVER THE SFO BAY AREA. AS FAR AS
THE VERY SHORT-TERM FORECAST IS CONCERNED...AFTER A QUIET
MORNING...THE LATEST HRRR IS SHOWING THE DEVELOPMENT OF
ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE TUCSON
CWA...GILA COUNTY...AND EVEN ACROSS SE CA AS THE UPPER LOW BEGINS TO
APPROACH THAT REGION...WHICH FITS WELL WITH OUR CURRENT GRIDDED AND
ZONE FORECASTS. OTHER THAN SOME MINOR ADJUSTMENTS TO THE HOURLY
TEMPERATURE AND DEWPOINT GRIDS...NO UPDATES ARE PLANNED.
&&
.PREVIOUS DISCUSSION...
NOTE...FORECAST CONFIDENCE CONTINUES TO INCREASE WITH REGARDS TO A
GOOD CHANCE OF SHOWERS/THUNDERSTORMS OVER SOUTH CENTRAL AZ...
INCLUDING PHOENIX SATURDAY MORNING AND AFTERNOON WITH POSSIBLE HEAVY
RAIN.
TODAY AND SATURDAY...
MOSTLY CLEAR SKIES WERE NOTED ACROSS THE ENTIRE FORECAST...SOUTHEAST
CA TO SOUTH CENTRAL AZ EARLY THIS MORNING. OTHERWISE THE LARGE
PACIFIC TROF CONTINUES ON TRACK TOWARD AZ FOR SATURDAY. THE FAVORED
GFS MODEL CONTINUES TO BE REMARKABLY CONSISTENT WITH ITS IMPACT OVER
OUR FORECAST AREA MAINLY LATE NIGHT...BUT PARTICULARLY SATURDAY.
THEREFORE THERE IS NOT MUCH CHANGE IN FORECAST THINKING FROM
YESTERDAY. INCREASING CLOUDS ARE EXPECTED ACROSS THE FORECAST AREA
TODAY...WITH A SLIGHT CHANCE OF PRECIP LATE IN THE DAY OVER
SOUTHEAST CA/SOUTHWEST AZ...AND OVER THE MOUNTAINS OF SOUTHERN GILA
COUNTY ZONE 24.
AS THE PACIFIC LOW APPROACHES LATER TODAY...UPPER LEVEL DYNAMICS
INCREASE ALONG THE COLORADO RIVER...WITH DYNAMICS SLOWLY SHIFTING
TOWARD PHOENIX LATE NIGHT. THEREFORE PRECIP PROBABILITIES ACROSS THE
FORECAST AREA WILL BE MUCH HIGHER OVER LA PAZ COUNTY IN SOUTHWEST AZ
TONIGHT.
DEVELOPING STORM DYNAMICS UNDER INCREASING MONSOON MOISTURE WILL BE
STRONGEST OVER SOUTH CENTRAL AZ...INCLUDING PHOENIX SATURDAY MORNING
AND EARLY AFTERNOON. THERE CONTINUES TO BE POTENTIAL FOR HEAVY RAIN
WITH CONVECTIVE STORMS. IN FACT THE STORM PREDICTION CENTER HAS
ISSUED A SLIGHT RISK FOR SEVERE THUNDERSTORMS IN NORTHERN AND
CENTRAL AZ...INCLUDING PHOENIX SATURDAY AFTERNOON. BELOW IS AN
EXCERPT FROM THEM ISSUED THURSDAY EVENING AT 1131 PM CDT.
WITH 50KT+ 500MB SPEED MAX FORECAST TO OVERSPREAD THE COLD
FRONT...SFC-6KM BULK SHEAR VALUES ARE SEASONALLY STRONG AND
SHOULD SUPPORT ORGANIZED POTENTIALLY ROTATING STORMS.
ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR ISOLATED
SUPERCELLS...ESPECIALLY IF BUOYANCY IS AT OR GREATER THAN
CURRENTLY FORECAST. LARGE HAIL...LOCALLY DAMAGING WINDS AND
PERHAPS AN ISOLATED TORNADO ARE POSSIBLE WITH STRONGEST
CONVECTION.
THEREFORE OUR FORECAST CONFIDENCE FOR POTENTIAL WIDESPREAD SHOWERS
AND THUNDERSTORMS SATURDAY OVER PARTS OF SOUTHWEST AND MOSTLY SOUTH
CENTRAL AZ IS HIGH. HOWEVER BECAUSE OF THE NATURE OF FAST MOVING HIT
AND MISS THUNDERSTORMS...THE PREDICTION OF RAINFALL AMOUNTS IS NOT
AS CLEAR WITH REGARDS TO FLOOD OR FLASH FLOODING.
SHOWER POTENTIAL WILL MOVE INTO EASTERN AZ SATURDAY EVENING WITH THE
THE COLD FRONT...I.E. OVER SOUTHERN GILA COUNTY ZONE 24. CLEARING
SKIES ARE EXPECTED OVER SOUTHWEST AND SOUTH CENTRAL AZ LATE SATURDAY
EVENING AND NIGHT.
SUNDAY...
A MUCH DRIER AIRMASS FOLLOWING THE COLD FRONT WILL SPREAD ACROSS
SOUTHEAST CA...SOUTHWEST AND SOUTH CENTRAL AZ SUNDAY. HOWEVER...
DEEP MOISTURE WILL CONTINUE TO REMAIN ALONG THE EASTERN AZ BORDER
UNTIL SUNDAY NIGHT. A THREAT OF SHOWERS AND THUNDERSTORMS WILL
LINGER OVER THE MOUNTAINS OF SOUTHERN GILA COUNTY ON SUNDAY.
MONDAY THROUGH WEDNESDAY...
DRY WEATHER WITH NEAR SEASONAL TEMPERATURES ARE EXPECTED ACROSS THE
ENTIRE FORECAST AREA.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
INCREASED MOISTURE WILL LEAD TO EARLY TO MID AFTERNOON SHOWERS AND
THUNDERSTORMS OVER FAVORED HIGH TERRAIN AREAS. SOME OF THESE STORMS
SHOULD MAKE THEIR WAY INTO THE PHOENIX AREA EARLY THIS
EVENING...POSSIBLY AFFECTING AREA TERMINALS. A REMOTE THREAT FOR
SHOWERS WILL REMAIN THROUGH THE OVERNIGHT HOURS FRIDAY NIGHT AHEAD
OF AN APPROACHING COLD FRONT. WINDS WILL REMAIN LIGHT THROUGH THE
PERIOD WITH ONLY A SMALL WINDOW OF WESTERLY DIRECTIONAL FLOW MAINLY
LATE THIS AFTERNOON.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
WINDS WILL INCREASE THROUGH THE DAY TODAY WITH GUSTY WINDS EXPECTED
THIS AFTERNOON. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE
AS THE DAY PROGRESSES WITH THE BEST CHANCE GENERALLY BETWEEN 21Z-03Z
TODAY...AND FAVORING THE LOWER COLORADO RIVER VALLEY. SOME
THUNDERSTORMS TODAY MAY BE STRONG...POTENTIALLY PRODUCING STRONG
OUTFLOW WINDS. A SMALL CHANCE OF MAINLY SHOWERS WILL REMAIN THROUGH
THE OVERNIGHT HOURS TONIGHT AHEAD OF AN APPROACHING COLD FRONT THAT
IS EXPECTED TO SWEEP THROUGH THE AREA SOME TIME SATURDAY MORNING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
SHOWERS AND THUNDERSTORMS...MAINLY EAST OF PHOENIX...ARE POSSIBLE ON
SUNDAY AS AN UPPER LEVEL TROUGH LINGERS OVER THE REGION. DRIER AIR
WILL BEGIN MOVING INTO THE AREA ON MONDAY...WITH LITTLE TO NO CHANCE
OF CONVECTION THE REMAINING PORTION OF THE FORECAST PERIOD.
AFTERNOON MINIMUM HUMIDITY LEVELS WILL AVERAGE AROUND 20 PERCENT ON
SUNDAY...AND THEN TREND TO AROUND 15 PERCENT BY THURSDAY. IN
ADDITION TO THE DRIER AIR...COOLER TEMPERATURES ARE EXPECTED THE
ENTIRE PERIOD. SOME GUSTY WEST TO SOUTHWEST WINDS ARE POSSIBLE ALONG
AND BEHIND THE TROUGH ON SUNDAY...THOUGH WIND SPEEDS WILL BE
GENERALLY LIGHT AND FOLLOW TYPICAL DIURNAL PATTERNS MONDAY THROUGH
THURSDAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/VASQUEZ
AVIATION...KUHLMAN
FIRE WEATHER...MCLANE
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
328 AM EDT FRI SEP 26 2014
.SYNOPSIS...
HIGH PRESSURE WILL REDEVELOP TO OUR WEST TODAY AND BUILD BACK ACROSS
THE AREA THROUGH THE WEEKEND. A COLD FRONT IS EXPECTED TO MOVE
ACROSS THE AREA MONDAY, THEN PUSH TO OUR SOUTH BY TUESDAY MORNING.
ANOTHER LOW PRESSURE SYSTEM MAY MOVE OFF THE SOUTHEAST COAST EARLY
NEXT WEEK AND MOVE NORTHWARD TOWARD OUR AREA THROUGH TUESDAY OR
WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WHAT FEW LOW CLOUDS REMAIN IN SOUTHERN DE SHOULD DISSIPATE EARLY
TODAY CLEARING THE WAY FOR A PLEASANT DAY ACROSS THE REGION. AS THE
UPPER LEVEL RIDGE SLIDES EAST, THICKNESS WILL INCREASE. EXPECT
TEMPERATURES NEAR OR JUST ABOVE NORMAL DESPITE THE CONTINUED
NORTHERLY SURFACE FLOW THROUGH THE DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
SHOULD KEEP ENOUGH OF A PRESSURE GRADIENT OVERNIGHT FOR WINDS TO
REMAIN 5 TO 10KT. OTHERWISE, EVERYTHING ELSE SUGGESTS PRIME
RADIATIONAL COOLING CONDITIONS (DRIER AIR, CLEAR SKIES). THUS, HAVE
GONE SLIGHTLY BELOW MAV/MET GUIDANCE FOR TEMPERATURES TONIGHT. LOWS
SHOULD RANGE FROM THE MID 40S IN THE HIGHER ELEVATIONS OF THE
POCONOS TO UPPER 50S FOR LOCATIONS NEAR THE COAST AND THE URBAN
CORRIDOR.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
FAIR WEATHER IS EXPECTED THROUGH THE WEEKEND AS HIGH PRESSURE IS
EXPECTED CONTINUE TO BUILD BACK ACROSS THE AREA WITH MOSTLY CLEAR
SKIES EXPECTED. THE ONLY WRINKLE TO THIS WOULD BE ANY PATCHY FOG
THAT COULD DEVELOP OVERNIGHT SATURDAY/SUNDAY MORNING AND ONVERNIGHT
SUNDAY/MONDAY MORNING. AS THICKNESSES RISE, TEMPERATURES WILL
REBOUND AS WELL, AND RISE BACK SEVERAL DEGREES ABOVE NORMAL, EVEN
REACHING THE 80S AGAIN SATURDAY AND SUNDAY.
A DRY FRONTAL BOUNDARY IS EXPECTED TO MOVE ACROSS THE AREA MONDAY,
THEN PUSH TO OUR SOUTH BY TUESDAY MORNING. THEN MODELS ARE SHOWING
ANOTHER LOW PRESSURE SYSTEM MOVING OFF THE SOUTHEAST COAST, THEN
MOVING NORTH JUST OFF THE EAST COAST THROUGH MID WEEK. THE GFS IS A
LITTLE FASTER THAN THE ECMWF, BUT THEY ARE FAIRLY SIMILAR IN HOW
CLOSE THEY BRING THE LOW TO OUR COAST. THIS BEARS WATCHING AS IT
COULD ONCE AGAIN HAVE AN EFFECT ON OUR WEATHER, BRINGING AN INCREASE
IN RAIN, WINDS, AND TIDAL PROBLEMS. PLENTY OF TIME TILL WE GET
THERE, SO IT MAY STILL PASS OUT TO SEA. FOR NOW WE WILL KEEP
CHANCE/SLIGHT CHANCE POPS FROM MONDAY NIGHT THROUGH WEDNESDAY,
WITH THE HIGHEST POPS ACROSS OUR EASTERN AREAS TUESDAY INTO
TUESDAY NIGHT.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
LOW CLOUDS HAVE ERODED, RESULTING IN MOSTLY VFR CONDITIONS WHICH
SHOULD CONTINUE THROUGH THE REMAINDER OF THE TAF PERIOD. THE ONCE
EXCEPTION IS FG/BR THAT HAS DEVELOPED IN SHELTERED VALLEYS INCLUDING
KRDG. THIS FG/BR WILL BE INTERMITTENT THROUGH 12Z, BUT SHOULD
DIMINISH QUICKLY WITH SUNRISE. FEW IF ANY CLOUDS ARE EXPECTED
THROUGH THE REMAINDER OF THE TAF PERIOD.
SURFACE NORTHERLY WINDS HAVE DECREASED. AT THE SAME TIME, VAD WIND
PROFILE FROM KDIX SHOWS PERSISTENT 35KT WINDS AT 1000 FT AGL. FOR
NOW, DO NOT EXPECT THIS TO RESULT IN LLWS AS THE STRONGER WINDS
SHOULD BE OVER EASTERN NJ, WHERE SURFACE WINDS ARE STILL NEAR 10KT.
FOR KABE AND KRDG WHERE WINDS ARE LIGHTER, HIGH RESOLUTION MODELS
SUCH AS THE RAP AND HRRR SHOW LOW LEVEL WINDS ONLY AS HIGH AS 25KT.
IN ADDITION, THE LOW LEVEL WINDS SHOULD DECREASE THROUGH 12Z AS THE
LOW LIFTS FURTHER AWAY FROM THE REGION. WILL WATCH THIS CLOSELY
THROUGH THE OVERNIGHT HOURS HOWEVER.
OUTLOOK...
SATURDAY-MONDAY...VFR CONDITIONS EXPECTED THROUGH THE PERIOD EXCEPT
POSSIBLE PATCHY FOG AT NIGHT AND EARLY MORNING HOURS.
MONDAY NIGHT-TUESDAY...MVFR/IFR CIGS/VSBYS, RAIN, AND GUSTY WINDS
POSSIBLE, ESPECIALLY FOR COASTAL SITES, AS POSSIBLE COASTAL LOW
PASSES BY.
&&
.MARINE...
AS THE LOW LIFTS FURTHER AWAY, WINDS CONTINUE TO DIMINISH. ON THE DE
BAY, WINDS (AND SEAS) SHOULD REMAIN BELOW SCA CRITERIA TODAY AND
TONIGHT. ON THE ATLANTIC WATERS, SEAS WILL BE SLOW TO FALL FROM THE
6 TO 8 FT THAT THEY ARE NOW TO 4 TO 5 FT BY LATE TONIGHT. WILL ALSO
SEE OCCASIONAL GUSTS TO 25KT EARLY TODAY, AND AGAIN POSSIBLE LATE
TONIGHT.
OUTLOOK...
SATURDAY...ADVISORY LEVEL SEAS ARE POSSIBLE ON THE ATLANTIC OCEAN
EARLY SATURDAY, BEFORE SUBSIDING BELOW ADVISORY LEVELS LATER IN THE
DAY.
SATURDAY NIGHT-MONDAY...SUB-ADVISORY CONDITIONS EXPECTED OVER THE
WEEKEND INTO MONDAY.
MONDAY NIGHT-TUESDAY...WINDS AND SEAS MAY INCREASE AHEAD OF A
POSSIBLE APPROACHING COASTAL LOW PRESSURE SYSTEM.
&&
.RIP CURRENTS...
EVEN THOUGH WEATHER CONDITIONS WILL BE BETTER TODAY, HIGHER WAVE
HEIGHTS LEFT OVER FROM THE DEPARTING COASTAL STORM WILL LEAD TO A
MODERATE RIP CURRENT RISK TODAY AND TONIGHT.
AN ENHANCED RIP CURRENT RISK MAY CONTINUE INTO SATURDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT SATURDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...JOHNSON
SHORT TERM...JOHNSON
LONG TERM...ROBERTSON
AVIATION...JOHNSON/ROBERTSON
MARINE...JOHNSON/ROBERTSON
RIP CURRENTS...JOHNSON
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
405 PM EDT FRI SEP 26 2014
.DISCUSSION...
TONIGHT...H85-H70 THETA-E BNDRY DRAPED OVER THE NE FL AND THE BIG
BEND COUPLED WITH A BAND OF +SHRAS/TSRAS OVER N LAKE/VOLUSIA
COUNTIES SUGGEST THE STUBBORN FRONTAL BNDRY HAS RETREATED N OF THE
I-4 CORRIDOR. DEEPENING E/SE FLOW WILL PULL SLIGHTLY DRIER AND MORE
STABLE AIR INTO THE CWA. HOWEVER...LATEST RUC ANALYSIS SHOWS
UPSTREAM H100-H70 MEAN RH REMAINS AOA 75PCT WHILE A BROAD AREA OF
ENHANCED H85-H50 VORTICITY CONTINUES TO BLANKET THE CENTRAL/SRN
PENINSULA. UPR LVLS NOT IN PLAY OVERNIGHT AS H30-H20 WINDS HAVE
DECREASED TO ARND 10KTS OVER MOST OF CENTRAL FL.
WITH LIMITED MID/UPR LVL DYNAMIC SUPPORT...PRECIP OVER THE INTERIOR
WILL DISSIPATE BY LATE EVNG AS THE CURRENT CONVECTION BURNS UP THE
AVAILABLE ENERGY WELL BEFORE SUNSET. THE ONSHORE FLOW...MOISTURE...
AND INSTABILITY WILL COMBINE TO ALLOW CHC/SLGT CHC OF COASTAL
SHRAS...BUT THERE WILL BE ENOUGH OF A SE STEERING COMPONENT THAT
WILL CARRY ANY ACTIVITY UP THE COAST RATHER THAN PUSHING IT INLAND.
WILL END PRECIP OVER THE INTERIOR BY 02Z...CONTG ALONG THE COAST
OVERNIGHT. CLOUD COVER AND LIGHT ONSHORE BREEZE KEEP MIN TEMPS IN
THE L/M70S.
SAT-SAT NIGHT...
WEAK RIDGING WILL NUDGE INTO THE LCL ATLC AS THE INVERTED TROF
OVERHEAD PUSHES INTO THE CENTRAL GOMEX SFC. DEEP E/SE FLOW WILL PUSH
SLIGHTLY DRIER AIR INTO CENTRAL FL...THOUGH PWAT VALUES WILL ONLY
DIMINISH TO ARND 2.0". TEMP PROFILE WILL REMAIN RATHER WEAK AS
UPSTREAM H70 TEMPS INCREASE TO ARND 9C...H50 TO ARND -5C...YIELDING
LAPSE RATES ARND 5.6C/KM AT BEST. STILL...THE WIND FIELDS REFLECT A
FAIRLY TYPICAL LATE SUMMER PATTERN OF DIURNAL CONVECTION WITH THE
ERLY FLOW FORCING PRECIP TOWARD THE W FL COAST THRU THE DAY.
SCATTERED SHOWERS AND ISOLATED STORMS NEAR THE EAST COAST IN THE
MORNING WILL SHIFT INLAND...POPS WILL REFLECT THIS MOTION WITH 40PCT
NEAR THE COAST AND 50PCT INTERIOR. LCL HEAVY RAIN THREAT WILL
CONTINUE AS THE H85-H50 STEERING FLOW WILL NOT SUPPORT WRLY STORM
MOTION MUCH HIGHER THAN 10MPH. CONSIDERABLE CLOUDINESS WILL CONTINUE
WITH HIGH TEMPERATURES IN THE UPPER 80S COAST TO NEAR 90 OVER THE
INTERIOR.
SUN-SUN NIGHT...(PREV DISC)
DEEP MOISTURE REMAINS ACROSS E CENTRAL FL WITH LOW LVL SE FLOW AND
THE GFS MODEL INDICATING SFC LOW PRESSURE DEVELOPING NEAR THE NRN
GULF COAST LATE IN THE DAY. APPEARS ANOTHER MID LVL S/W DISTURBANCE
ACROSS THE SRN PENINSULA WILL LEAD TO A CONVECTIVELY ACTIVE
AFTERNOON FOR E CENTRAL FL WITH MID LVL FLOW FROM S/SSW FOCUSING
SHOWERS AND STORMS ACROSS THE AREA BY AFTERNOON AND OVER THE
INTERIOR IN THE LATE AFTN AND EVENING. LOCALLY HEAVY RAIN WILL AGAIN
BE A CONCERN WITH STORMS MOVING FROM THE SOUTH TO NORTH AT AROUND 10
MPH.
EXTENDED...(PREV DISC)
MON-TUE...HIGH RAIN CHANCES WILL CONTINUE INTO MONDAY AND TUESDAY AS
A 500 MB S/W TROUGH ACROSS THE SE STATES ALLOWS AN AREA OF LOW
PRESSURE TO DEVELOP ACROSS THE FL PANHANDLE MONDAY AND MOVE ENE OFF
THE GA/SC COAST BY TUE AFTERNOON. GFS INDICATES SEVERAL MID LVL
IMPULSES WILL MOVE ACROSS THE PENINSULA ON MONDAY AHEAD OF THE MAIN
S/W TROUGH TO THE NORTH. WITH DEEP MOISTURE RETURNING OVER FL FROM
THE ERN GULF AHEAD OF THIS SYSTEM SHOWERS AND THUNDERSTORMS WILL BE
LIKELY MONDAY AND ACROSS MUCH OF THE AREA TUESDAY AS WELL AHEAD OF
THE NEXT FRONT. WITH THE HEAVY RAINFALL ACROSS PORTIONS OF EAST
CENTRAL FL THE PAST WEEK...THE RISK FOR LOCALLY HEAVY RAIN WITH
STORMS APPEARS LIKELY LEADING TO THE RISK OF FLOODING AS WE STAY IN
THE WET PATTERN INTO EARLY NEXT WEEK.
WED-FRI...00Z GFS/ECMWF BEGIN TO SHOW SIGNIFICANT DIFFERENCES ON THE
SOUTHWARD PROGRESSION OF THE DEEP MOISTURE AND COOL FRONT INTO MID
WEEK TO LATE. THE GFS BRINGS SOME A MUCH DRIER AIRMASS ACROSS
NRN/CENTRAL SECTIONS WED/THU WHILE THE ECMWF KEEPS DEEP MOISTURE
OVER CENTRAL FL. HAVE TRENDED TOWARD A BLEND OF THESE TWO SOLUTIONS
WITH SOMEWHAT HIGHER RAIN CHANCES LINGERING WED/THU ACROSS THE SOUTH
HALF OF THE AREA. RAIN CHANCES WILL BE NEAR CLIMO INTO FRIDAY
WITH ADEQUATE MOISTURE FOR SHOWERS AND A CHANCE OF STORMS.
&&
.AVIATION...
WINDS: THRU 27/01Z...N OF KMLB-KISM E/NE ARND 10KTS BCMG E...S OF
KMLB-KISM E/SE ARND 10KTS. BTWN 27/01Z-27/04Z...BCMG E/NE AOB 5KTS
ALL SITES...CONTG THRU 27/13Z. AFT 27/13Z...E/SE 8-12KTS ALL SITES.
CIGS/VSBYS: THRU 27/00Z...NW OF KMLB-KOBE NMRS MVFR/SCT IFR
SHRAS/ISOLD LIFR TSRAS...E OF KMLB-KOBE ISOLD MVFR SHRAS...STORM
MOTION NW ARND 10KTS. BTWN 17/00Z-17/03Z...N OF KMLB-KOBE SCT MVFR
SHRAS/ISOLD IFR TSRAS...S OF KMLB-KOBE ISOLD MVFR SHRAS. AFT
17/03Z...ISOLD MVFR SHRAS COASTAL SITES...VFR INTERIOR SITES.
&&
.MARINE...
TONIGHT...FRONTAL BOUNDARY HAS RETREATED INTO THE NRN PENINSULA/BIG
BEND REGION...ALLOWING A LIGHT TO GENTLE E/SE BREEZE TO DVLP ACRS
THE LCL ATLC IN ITS WAKE. WIND BCMG GENTLE TO MODERATE OVERNIGHT AS
A WEAK OFF THE CAROLINA COAST BEGINS TO DAMPEN OUT AS HI PRES BUILDS
OFF THE MID ATLC COAST. SEAS 2-3FT NEARSHORE AND 3-4FT OFFSHORE...
MAINLY DUE TO A 2-3FT ERLY SWELL...DOMINANT PERIODS ARND 8SEC.
SAT-TUE...E WNDS 10-15KTS KNOTS ON SAT BCMG SE ARND 10KTS FOR SUN.
SEAS 3FT NEAR SHORE TO 4FT OFFSHORE IN AN ERLY SWELL. WINDS BCMG
S/SW ON MON AHEAD OF THE NEXT FRONT. FRONT WILL PUSH INTO N FL ON
TUE WITH W/SW WINDS INCRSG TO 10-15KTS. HIGHER PRECIP COVERAGE
MON-TUE WITH STORMS MVG OFFSHORE EAST AFTN. SEAS 3FT NEAR SHORE AND
UP TO AROUND 4 FT OFFSHORE.
&&
.HYDROLOGY...
ST JOHNS RIVER AT ASTOR REMAINS WITHIN ACTION STAGE AS OF FRIDAY
AFTERNOON. THE NORTHERLY WIND FLOW THAT WAS HELPING TO CONTRIBUTE TO
THE HIGH RIVER LEVELS ON THURSDAY HAS ABATED...HOWEVER...HEAVY RAIN
OVER THE BASIN NEAR ASTOR WILL CONTINUE TO KEEP THE RIVER LEVEL
ELEVATED THROUGH THE WEEKEND. LEVELS WILL REMAIN AT OR JUST SLIGHTLY
BELOW ACTION STAGE FOR THE NEXT FEW DAYS.
SHINGLE CREEK NEAR CAMPBELL CONTINUES TO SLOWLY FALL AS OF FRIDAY
AFTERNOON...HOWEVER...RECENT HEAVY RAINS THIS AFTERNOON WILL LIKELY
CAUSE THE RIVER TO LEVEL OFF...IF NOT SLOWLY RISE THROUGH THIS
EVENING REMAINING JUST BELOW ACTION STAGE. THIS AREA IS MORE
SUSCEPTIBLE TO FASTER RISES THAN THE ST JOHNS...SO WILL CONTINUE TO
MONITOR AND RUN LOCAL MODEL AS NEEDED OVER THE NEXT FEW DAYS.
ELSEWHERE...ANY HEAVY RAINFALL ON ALREADY SATURATED GROUND MAY
AGGRAVATE ANY ONGOING STANDING WATER ISSUES AND LEAD TO ADDITIONAL
MINOR FLOODING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 74 87 77 89 / 30 40 30 50
MCO 74 91 75 91 / 30 50 20 50
MLB 77 87 78 88 / 30 40 30 50
VRB 75 89 77 90 / 30 40 30 50
LEE 74 92 75 91 / 30 50 20 50
SFB 74 92 75 92 / 30 50 20 50
ORL 75 92 76 92 / 30 50 20 50
FPR 76 88 77 89 / 30 40 30 50
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
RADAR/IMPACT WX.......CRISTALDI
HYDROLOGY.............ULRICH
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
230 PM EDT FRI SEP 26 2014
.SYNOPSIS...
18Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A HIGHLY AMPLIFIED AND
UNPROGRESSIVE NORTHERN STREAM FLOW OVER NORTH AMERICA. MAIN FLOW
ARRIVES WITHIN A DEEP TROUGH OVER THE CALIFORNIA COAST BEFORE
QUICKLY RIDGING WELL NORTH INTO CENTRAL CANADA. THE FLOW THEN
FLATTENS OUT DOWNSTREAM AND BECOMES MORE ZONAL BY THE TIME IT
REACHES THE CANADIAN MARITIMES. SOUTH OF THIS MAIN FLOW WE FIND A
WEAK SHORTWAVE DROPPING SOUTHEAST OUT OF NEW ENGLAND OVERTOP AN
UPPER RIDGE CENTERED OFF THE SOUTHEAST CONUS COAST. OUR FORECAST
REGION REMAINS ON THE VERY WESTERN PERIPHERY OF THIS RIDGE
CIRCULATION...ALTHOUGH THE 26/12Z KTBW SOUNDING PROFILE DOES NOT
SHOW MUCH CONSISTENCY WITH THE WIND DIRECTION THROUGH ANY DEPTH OF
THE COLUMN.
AS ADVERTISED BY THE MODELS...THE PW HAS BEEN RISING AND IS NOW
OVER 2.2" AT KTBW...AND APPROACHING 2.4" AT KMFL. AS WOULD BE
EXPECTED WITH SUCH A MOIST PROFILE...LAPSE RATES ARE FAIRLY
POOR...GENERALLY IN THE VICINITY OF MOIST ADIABATIC THROUGH MUCH OF
THE COLUMN. THEREFORE...THE COLUMN IS VERY FAVORABLE FOR
CONVECTION...BUT UNFAVORABLE FOR SEVERE TYPE UPDRAFTS. THIS IS NOT
TO SAY THAT A FEW STRONGER STORMS ARE NOT POSSIBLE GIVEN PROPER LOW
LEVEL MOISTURE POOLING TO INCREASE THE CAPE POTENTIAL...
HOWEVER...OVERALL THESE TYPE OF STORMS SHOULD BE FEW AND FAR BETWEEN
LATE TODAY. THE GREATER THREAT FROM TODAYS STORMS WILL BE THE
POTENTIAL FOR LOCALLY VERY HEAVY RAINFALL. SOME SPOTS HAVE SEEN
CONSIDERABLE RAINFALL ALREADY THIS WEEK...AND WILL NEED TO BE
WATCHED CLOSELY SHOULD ANOTHER HEAVY RAINFALL EVENT OCCUR NEARBY.
BASED ON DISCUSSION OF CONDITIONS WITH COUNTY OFFICIALS...A FLASH
FLOOD WATCH HAS BEEN ISSUED FOR POLK...HIGHLANDS...AND HARDEE
COUNTIES THROUGH THE EVENING.
AT THE SURFACE...PRESSURE GRADIENT IS PROVIDING A SHALLOW LAYER OF
NORTHEAST TO EAST FLOW BETWEEN A LARGE RIDGE OF HIGH PRESSURE OVER
THE DEEP SOUTH AND AN INVERTED TROUGH PROGRESSING WESTWARD ACROSS
THE FLORIDA PENINSULA. THIS TROUGH ALONG WITH A FEEBLE SEA-BREEZE
(OR AT LEAST DEVELOPING COASTAL SPEED CONVERGENCE) WILL PROVIDE THE
FOCUS FOR ACTIVE SHOWERS AND STORMS THE REMAINDER OF THE DAY.
REGIONAL RADARS ARE ALREADY GETTING QUITE ACTIVE OVER THE SOUTHERN
ZONES AND ACROSS THE INTERIOR CENTRAL PENINSULA. THIS ACTIVITY WILL
CONTINUE TO EXPAND AND MIGRATE WEST THROUGH THE NEXT SEVERAL HOURS.
HIGH RAIN CHANCES INTO THE EARLY EVENING STILL LOOK ON TRACK.
&&
.SHORT TERM (TONIGHT AND SATURDAY)...
TONIGHT...
FIRST PART OF THE NIGHT / EVENING HOURS SHOULD STILL SEE SOME SCT
STORMS ALONG THE I-75 CORRIDOR AND TOWARD THE COAST WITH THE
ACTIVITY SLOWLY MIGRATING OFFSHORE INTO THE EASTERN GULF. THE SECOND
HALF OF THE OVERNIGHT SHOULD BE MAINLY DRY OVER THE LAND ZONES WITH
CONTINUED SHOWERS/STORMS ONGOING OVER THE COASTAL WATERS. LOW
TEMPERATURES BY SUNRISE SATURDAY WILL BE IN THE LOWER 70S NORTH AND
LOWER TO MIDDLE 70S SOUTH.
SATURDAY...
THE DAY WILL START OFF WITH WITH MOSTLY DRY AND QUIET CONDITIONS
OVER THE LAND ZONES...WHILE THE SURFACE TROUGH (OVER THE EASTERN
GULF) KEEPS THE LOW LEVEL FOCUS FOR AT LEAST SCT SHOWERS/STORM GOING
OVER THE COASTAL WATERS. TWO THINGS CHANGE ON SATURDAY COMPARED TO
TODAY. FIRST...THE SURFACE TROUGH WILL NOW BE PAST THE FL PENINSULA
AND CONTINUE TO MIGRATE WESTWARD THROUGH THE DAY. SECOND...THE
EASTERLY FLOW JUST ABOVE THE SURFACE WILL BE A LITTLE STRONGER AND
MORE DEFINED. LOOKS AS THOUGH THIS FLOW WILL BE STRONG ENOUGH TO
PREVENT MUCH OF A SEA-BREEZE FROM FORMING...OR WILL KEEP AND FEEBLE
CIRCULATION PINNED AT OR JUST OFFSHORE OF THE COAST. SO...WE ARE
LOSING SOME OF OUR FOCUSING MECHANISMS FOR ORGANIZED UPDRAFTS. THIS
EFFECT WILL BE MOST FELT INLAND FROM THE I-75 CORRIDOR. IN
ANTICIPATION OF AT LEAST MEAGER ENHANCED CONVERGENCE RIGHT AT THE
COAST...WILL HAVE BEST SHOWER/STORM CHANCES SATURDAY MID AFTERNOON
THROUGH EARLY EVENING ALONG AND WEST THE I-75 CORRIDOR. FURTHER
INLAND WILL HAVE LOWER RAIN CHANCES AND DIMINISH THOSE RAIN CHANCES
EARLIER. THE COLUMN WILL STILL BE QUITE MOIST WITH PW VALUES WELL
ABOVE 2". SO...THE COLUMN WILL BE FAVORABLE FOR CONVECTION SHOULD
THE PROPER LOW LEVEL TRIGGER BE IN PLACE. GOOD AGREEMENT IN BOTH THE
STATISTICAL AND CONVECTION ALLOWING GUIDANCE SUITES IN THIS WEST TO
EAST POP GRADIENT...SO CONFIDENCE IS HIGHER THAN AVERAGE.
TEMPERATURES LOOK SEASONABLE WITH HIGHS WITHIN A DEGREE OR 2 EITHER
SIDE OF 90.
&&
.LONG TERM (SATURDAY NIGHT-FRIDAY)...
MODEL GUIDANCE OVERALL REMAINS IN VERY GOOD AGREEMENT WITH RESPECT
TO SYNOPTIC WEATHER FEATURES THROUGH THE LONG TERM PERIODS. UPPER
LEVEL RIDGING WILL HOLD IN PLACE ACROSS THE FORECAST AREA THROUGH
THE WEEKEND...WITH MORE OF A ZONAL FLOW THEN SETTING UP ACROSS THE
PENINSULA DURING THE FIRST HALF OF NEXT WEEK AS UPPER LEVEL TROUGH
SKIRTS BY TO THE NORTH THROUGH THE DEEP SOUTH AND SOUTHEAST
STATES. UPPER LEVEL RIDGING THEN LOOKS TO BUILD BACK INTO THE
REGION FOR THE SECOND HALF OF NEXT WEEK. AT THE SURFACE...A
FRONTAL BOUNDARY WILL START THE LONG TERM PERIODS ACROSS THE
NORTHERN GULF COAST...AND SLOWLY SHIFT SOUTHWARD INTO CENTRAL
FLORIDA BY THE MIDDLE OF NEXT WEEK. THE FRONTAL BOUNDARY WILL THEN
BEGIN TO LIFT BACK NORTHWARD AND INTO NORTH FLORIDA BY THE END OF
NEXT WEEK.
AS FOR FORECAST DETAILS...THE DEEPEST MOISTURE WILL REMAIN ALONG
AND TO THE SOUTH OF THE MEANDERING FRONTAL BOUNDARY THROUGH THE
PERIOD. GIVEN THE PROXIMITY OF THE BOUNDARY TO THE FORECAST
AREA...NOT EXPECTING MUCH CHANGE TO THE OVERALL PATTERN OF
LATE...WITH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
EXPECTED MAINLY DURING THE AFTERNOON AND EVENING HOURS EACH DAY.
THERE WILL BE AN INCREASED POTENTIAL FOR LATE NIGHT AND EARLY
MORNING SHOWERS AND THUNDERSTORMS IN COASTAL LOCALES MONDAY
THROUGH WEDNESDAY HOWEVER...AS THE FRONTAL BOUNDARY PUSHES INTO
CENTRAL FLORIDA SUPPRESSING THE MEAN SURFACE RIDGE AXIS SOUTH OF
THE STATE. TEMPERATURES ARE EXPECTED TO REMAIN CLOSE TO CLIMATOLOGY
THROUGH THE LONG TERM PERIODS.
&&
.AVIATION...
NUMEROUS SHOWERS AND THUNDERSTORMS ARE NOW PROGRESSING WESTWARD
ACROSS THE PENINSULA. KPGD/KFMY/KRSW ARE ALREADY SEEING THE
INCLEMENT WEATHER...AND SHOWERS WILL REMAIN POSSIBLE FOR THE NEXT
SEVERAL HOURS. THE REST OF THE TERMINALS UP INTO THE TAMPA BAY
REGION WILL SEE THE ACTIVITY ARRIVE DURING THE LATER AFTERNOON
HOURS. AWAY FROM THE STORMS VFR CONDITIONS WILL PREVAIL...BUT A
BRIEF MVFR/IFR VISIBILITY IS POSSIBLE IN THE VICINITY OF
THUNDERSTORMS. STORMS WILL MIGRATE OFF THE COAST WITHIN A FEW HOURS
OF SUNSET WITH PREVAILING VFR CONDITIONS THROUGH THE REMAINDER OF
THE OVERNIGHT AND SATURDAY MORNING.
&&
.MARINE...
LITTLE CHANGE FROM YESTERDAY AS A SURFACE TROUGH REMAINS IN PLACE
OVER THE EASTERN GULF WATERS AND DEEP TROPICAL MOISTURE REMAINS OVER
THE AREA. SCATTERED TO NUMEROUS THUNDERSTORMS OVER THE FLORIDA EAST
COAST WILL MOVE SLOWLY WEST AND BE A THREAT TO THE COASTAL WATERS
TOWARD THE LATE AFTERNOON AND EVENING HOURS. LIGHT OFFSHORE WINDS
AGAIN TODAY WITH A MILD SEA BREEZE AFFECT FOR THE SECOND HALF OF THE
DAY. THE MAIN HAZARDS WILL CONTINUE TO BE HIGHER WINDS AND SEAS IN
THE VICINITY OF THUNDERSTORMS.
&&
.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER CONCERNS ARE EXPECTED THROUGH THE
WEEKEND. THE PATTERN WILL BECOME MORE SUMMER-LIKE OVER THE NEXT FEW
DAYS WITH MAINLY AFTERNOON AND EVENING SHOWERS AND STORMS. RELATIVE
HUMIDITY VALUES WILL REMAIN WELL ABOVE CRITICAL LEVELS.
PATCHY GROUND FOG IS POSSIBLE EACH OF THE NEXT FEW MORNING...HOWEVER
NO WIDESPREAD FOG OR VISIBILITY ISSUES ARE ANTICIPATED.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 75 89 76 89 / 40 60 40 50
FMY 74 90 74 91 / 30 60 20 60
GIF 74 90 74 90 / 20 50 20 50
SRQ 75 90 74 89 / 50 60 40 50
BKV 73 91 72 90 / 30 60 30 60
SPG 77 89 77 89 / 50 60 40 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR HARDEE-
HIGHLANDS-POLK.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/FIRE WX...MROCZKA
MARINE...DOUGHERTY
LONG TERM...JELSEMA
AREA FORECAST DISCUSSION
NWS MIAMI FL
124 PM EDT FRI SEP 26 2014
.AVIATION...
CONDITIONS HAVE BEEN FAIRLY QUIET ACROSS SOUTH FLORIDA TODAY AND
LIKELY WILL CONTINUE TO BE SO OVER THE ATLANTIC COAST TAF SITES.
THERE ARE SHOWERS AND THUNDERSTORMS EXPECTED THIS AFTERNOON FOR
THE GULF COAST. GIVEN THIS, HAVE DROPPED VCSH AND ANY VCTS FOR THE
EAST COAST FOR NOW, AND KEPT THE TEMPO GROUP FOR KAPF. HOWEVER,
WILL HAVE TO CONTINUE TO MONITOR THE CONDITIONS AND IF CONVECTION
BEGINS TO DEVELOP OVER THE EAST COAST, WILL HAVE TO AMEND THOSE
TAFS TO INDICATE THAT.
&&
.PREV DISCUSSION... /ISSUED 1050 AM EDT FRI SEP 26 2014/
UPDATE...
CLUSTER OF SHOWERS AND THUNDERSTORMS OFFSHORE PALM BEACH COUNTY IS
BEGINNING TO DIMINISH IN INTENSITY WITH ONLY ISOLATED SHOWERS
ACROSS THE MAINLAND. LATEST HRRR INITIALIZES FAIRLY WELL AND DOES
DEPICT CONVECTIVE COVERAGE INCREASING ACROSS THE INTERIOR OVER THE
NEXT FEW HOURS WITH HEATING. TWEAKED POP AND WEATHER GRIDS THROUGH
18Z TO ACCOUNT FOR THE LATEST TRENDING. UPDATE SENT.
PREV DISCUSSION... /ISSUED 246 AM EDT FRI SEP 26 2014/
SHORT TERM (TODAY-SUNDAY)...
ATLANTIC RIDGE HAS BEGUN TO BUILD BACK TO THE WEST ACROSS THE
FLORIDA PENINSULA WITH A WEAK SURFACE INVERTED TROUGH LOCATED ALONG
THE EAST COAST. THIS HAS CONTINUED AN ACTIVE PATTERN OF OVERNIGHT
CONVECTION OVER THE ATLANTIC WATERS AND ALONG THE IMMEDIATE EAST
COAST WITH SLOW MOVEMENT TO THE NORTH-NORTHWEST. THERE IS A LITTLE
UNCERTAINTY AS TO THE PATTERN OF DEVELOPMENT FOR THE REST OF
TODAY AS THE GFS DOES NOT DRY THE ATMOSPHERE AS IN PAST RUNS
KEEPING THE PWAT CLOSE TO 2" AND WITH A MUCH SHALLOWER EASTERLY
FLOW. THIS WOULD TRANSLATE TO A CONTINUATION OF POSSIBLE LOCALLY
HEAVY RAINS JUST ABOUT ANYWHERE. HOWEVER, THE ECMWF IS SHOWING THE
DEEPER EASTERLY FLOW AND WITH PWAT LOWERING TO AROUND 1.75". THE
00Z MFL SOUNDING SHOWED THE DEEP SOUTHEAST FLOW IN PLACE AT THAT
TIME AND SEE LITTLE REASON TO BELIEVE MUCH WOULD CHANGE IN THE
OVERNIGHT PERIOD. FOR THIS REASON, WOULD TEND TO LEAN TOWARDS THE
GFS SOLUTION. IN THIS THINKING, THE HRRR DOES KEEP THE EAST COAST
RATHER ACTIVE THROUGH MUCH OF THE MORNING BEFORE SHIFTING INLAND
DURING THE EARLY AFTERNOON. THE SATELLITE DERIVED PWAT IMAGERY
DOES SHOW SOME DRYING HEADED OUR WAY BUT IT IS NOT SIGNIFICANT WITH
LEADING EDGE STILL ROUGHLY 250 MILES TO OUR EAST. SO AM A LITTLE
RELUCTANT TO SAY AT THIS TIME MUCH IN THE WAY OF LOWER POPS BUT IT
WOULD APPEAR THAT THE MAIN THREAT FOR HEAVIER RAINS WILL BE DURING
THE MORNING NEAR THE EAST COAST AND ACROSS THE INTERIOR AND WEST
COAST REGION DURING THE AFTERNOON PERIOD.
THE ATLANTIC RIDGE WILL REMAIN THE DOMINANT FEATURE OVER THE WEEKEND
WITH SOME SLOW DRYING OCCURRING IN THE UPPER LEVELS. A WEAK SURFACE
RIDGE WILL ALSO DEVELOP NORTH OF THE REGION AS THE WEAK TROUGH FADES
AWAY WITH LACK OF UPPER SUPPORT. EVEN THOUGH SOME DRYING WILL OCCUR,
PWAT`S WILL BE AT NORMAL LEVELS FOR LATE SEPTEMBER NEAR 1.75". THE
GFS KEEPS THE SOUTHEASTERLY FLOW RATHER SHALLOW ON SATURDAY BUT THEN
DEEPENS IT ON SUNDAY. SO THE PATTERN COULD STILL FAVOR ATLANTIC
ACTIVITY DURING THE NIGHTTIME HOURS PUSHING ONSHORE ALONG THE EAST
COAST AND THEN FAVORING INTERIOR AND WEST COAST AREAS EACH AFTERNOON.
LONG TERM (MONDAY-THURSDAY)...
GLOBAL MODELS CONTINUE TO BE IN GOOD AGREEMENT NEXT WEEK IN
DEVELOPING CYCLONIC FLOW ACROSS MUCH OF THE NATION WITH A STRONG
MID/UPPER LEVEL TROUGH MOVING THROUGH THE SOUTHEAST STATES EARLY IN
THE WEEK. THE CYCLONIC FLOW PATTERN WILL SUPPRESS THE UPPER RIDGE
TO OUR SOUTH AND THIS WILL PLACE SOUTH FLORIDA IN A WESTERLY
STEERING FLOW FOR MUCH OF NEXT WEEK WITH PWAT`S RUNNING IN THE
1.75-2" RANGE. SO THE EAST COAST METRO AREAS COULD EXPERIENCE SOME
THREAT FOR LOCALLY HEAVY RAINS ONCE AGAIN ESPECIALLY EARLY IN THE
PERIOD.
MARINE...
A LIGHT TO MODERATE EAST WIND FLOW WILL CONTINUE THROUGH THE
WEEKEND. THE FLOW WILL THEN VEER TO THE SOUTHWEST EARLY NEXT WEEK
AS THE HIGH PRESSURE GETS SUPPRESSED TO THE SOUTH OF THE LOCAL
WATERS. SEAS THROUGH THE PERIOD WILL GENERALLY BE 2-3 FEET IN THE
ATLANTIC WITH 2 FEET OR LESS OVER THE GULF WATERS. SHOWERS AND
THUNDERSTORMS CAN ALSO BE EXPECTED EACH DAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 86 78 83 / 20 30 20 30
FORT LAUDERDALE 79 88 79 88 / 20 30 30 40
MIAMI 78 88 77 88 / 20 30 20 20
NAPLES 76 90 76 90 / 30 60 30 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...10/CD
LONG TERM....30/KOB
AVIATION...13/SI
AREA FORECAST DISCUSSION
NWS MIAMI FL
1050 AM EDT FRI SEP 26 2014
.UPDATE...
CLUSTER OF SHOWERS AND THUNDERSTORMS OFFSHORE PALM BEACH COUNTY IS
BEGINNING TO DIMINISH IN INTENSITY WITH ONLY ISOLATED SHOWERS
ACROSS THE MAINLAND. LATEST HRRR INITIALIZES FAIRLY WELL AND DOES
DEPICT CONVECTIVE COVERAGE INCREASING ACROSS THE INTERIOR OVER THE
NEXT FEW HOURS WITH HEATING. TWEAKED POP AND WEATHER GRIDS THROUGH
18Z TO ACCOUNT FOR THE LATEST TRENDING. UPDATE SENT.
&&
.PREV DISCUSSION... /ISSUED 744 AM EDT FRI SEP 26 2014/
AVIATION...
A WEAK TROUGH WILL KEEP UNSETTLED WEATHER ACROSS SOUTH FLORIDA
THROUGH THE TAF PERIOD. SHOWERS WILL MOVE WEST, OFF THE ATLANTIC,
AND BRING SHOWERS AND SOME THUNDERSTORMS TO THE AREA BY MID
MORNING AND LAST INTO THE AFTERNOON. THEY ARE EXPECTED TO MOVE
FURTHER INLAND SOMETIME IN THE MID AFTERNOON, SO THE VCTS IN THE
TAFS MAY BE ABLE TO END A COUPLE OF HOURS EARLIER, DEPENDING HOW
FAST THEY DO MOVE INLAND. OTHERWISE, VFR CONDITIONS THROUGH THE
TAF PERIODS, WITH BRIEF IFR POSSIBLE UNDER HEAVY SHOWERS AND
THUNDERSTORMS.
PREV DISCUSSION... /ISSUED 246 AM EDT FRI SEP 26 2014/
SHORT TERM (TODAY-SUNDAY)...
ATLANTIC RIDGE HAS BEGUN TO BUILD BACK TO THE WEST ACROSS THE
FLORIDA PENINSULA WITH A WEAK SURFACE INVERTED TROUGH LOCATED ALONG
THE EAST COAST. THIS HAS CONTINUED AN ACTIVE PATTERN OF OVERNIGHT
CONVECTION OVER THE ATLANTIC WATERS AND ALONG THE IMMEDIATE EAST
COAST WITH SLOW MOVEMENT TO THE NORTH-NORTHWEST. THERE IS A LITTLE
UNCERTAINTY AS TO THE PATTERN OF DEVELOPMENT FOR THE REST OF
TODAY AS THE GFS DOES NOT DRY THE ATMOSPHERE AS IN PAST RUNS
KEEPING THE PWAT CLOSE TO 2" AND WITH A MUCH SHALLOWER EASTERLY
FLOW. THIS WOULD TRANSLATE TO A CONTINUATION OF POSSIBLE LOCALLY
HEAVY RAINS JUST ABOUT ANYWHERE. HOWEVER, THE ECMWF IS SHOWING THE
DEEPER EASTERLY FLOW AND WITH PWAT LOWERING TO AROUND 1.75". THE
00Z MFL SOUNDING SHOWED THE DEEP SOUTHEAST FLOW IN PLACE AT THAT
TIME AND SEE LITTLE REASON TO BELIEVE MUCH WOULD CHANGE IN THE
OVERNIGHT PERIOD. FOR THIS REASON, WOULD TEND TO LEAN TOWARDS THE
GFS SOLUTION. IN THIS THINKING, THE HRRR DOES KEEP THE EAST COAST
RATHER ACTIVE THROUGH MUCH OF THE MORNING BEFORE SHIFTING INLAND
DURING THE EARLY AFTERNOON. THE SATELLITE DERIVED PWAT IMAGERY
DOES SHOW SOME DRYING HEADED OUR WAY BUT IT IS NOT SIGNIFICANT WITH
LEADING EDGE STILL ROUGHLY 250 MILES TO OUR EAST. SO AM A LITTLE
RELUCTANT TO SAY AT THIS TIME MUCH IN THE WAY OF LOWER POPS BUT IT
WOULD APPEAR THAT THE MAIN THREAT FOR HEAVIER RAINS WILL BE DURING
THE MORNING NEAR THE EAST COAST AND ACROSS THE INTERIOR AND WEST
COAST REGION DURING THE AFTERNOON PERIOD.
THE ATLANTIC RIDGE WILL REMAIN THE DOMINANT FEATURE OVER THE WEEKEND
WITH SOME SLOW DRYING OCCURRING IN THE UPPER LEVELS. A WEAK SURFACE
RIDGE WILL ALSO DEVELOP NORTH OF THE REGION AS THE WEAK TROUGH FADES
AWAY WITH LACK OF UPPER SUPPORT. EVEN THOUGH SOME DRYING WILL OCCUR,
PWAT`S WILL BE AT NORMAL LEVELS FOR LATE SEPTEMBER NEAR 1.75". THE
GFS KEEPS THE SOUTHEASTERLY FLOW RATHER SHALLOW ON SATURDAY BUT THEN
DEEPENS IT ON SUNDAY. SO THE PATTERN COULD STILL FAVOR ATLANTIC
ACTIVITY DURING THE NIGHTTIME HOURS PUSHING ONSHORE ALONG THE EAST
COAST AND THEN FAVORING INTERIOR AND WEST COAST AREAS EACH AFTERNOON.
LONG TERM (MONDAY-THURSDAY)...
GLOBAL MODELS CONTINUE TO BE IN GOOD AGREEMENT NEXT WEEK IN
DEVELOPING CYCLONIC FLOW ACROSS MUCH OF THE NATION WITH A STRONG
MID/UPPER LEVEL TROUGH MOVING THROUGH THE SOUTHEAST STATES EARLY IN
THE WEEK. THE CYCLONIC FLOW PATTERN WILL SUPPRESS THE UPPER RIDGE
TO OUR SOUTH AND THIS WILL PLACE SOUTH FLORIDA IN A WESTERLY
STEERING FLOW FOR MUCH OF NEXT WEEK WITH PWAT`S RUNNING IN THE
1.75-2" RANGE. SO THE EAST COAST METRO AREAS COULD EXPERIENCE SOME
THREAT FOR LOCALLY HEAVY RAINS ONCE AGAIN ESPECIALLY EARLY IN THE
PERIOD.
MARINE...
A LIGHT TO MODERATE EAST WIND FLOW WILL CONTINUE THROUGH THE
WEEKEND. THE FLOW WILL THEN VEER TO THE SOUTHWEST EARLY NEXT WEEK
AS THE HIGH PRESSURE GETS SUPPRESSED TO THE SOUTH OF THE LOCAL
WATERS. SEAS THROUGH THE PERIOD WILL GENERALLY BE 2-3 FEET IN THE
ATLANTIC WITH 2 FEET OR LESS OVER THE GULF WATERS. SHOWERS AND
THUNDERSTORMS CAN ALSO BE EXPECTED EACH DAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 78 86 78 / 50 20 30 20
FORT LAUDERDALE 87 79 88 79 / 50 20 30 30
MIAMI 87 78 88 77 / 50 20 30 20
NAPLES 89 76 90 76 / 70 30 60 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1025 AM EDT FRI SEP 26 2014
.DISCUSSION...
MOISTURE POOLING WITHIN A STALLED FRONTAL TROF OVER CENTRAL/S FL HAS
NEARLY SATURATED THE LCL AIRMASS...MORNING RAOBS AT KXMR/KTBW/KMFL
MEASURED 2.2"-2.4" PWATS. LATEST RUC ANALYSIS SHOWS A RIDGE AXIS
EXTENDING FROM BERMUDA TO THE NRN BAHAMAS WITH A LONG AND DEEP ERLY
SURGE E OF THE BAHAMA BANK. MID LVL VORT MAX OVER THE S HALF OF THE
PENINSULA IS EMBEDDED WITHIN DEEP S/SE FLOW THAT WILL PROVIDE A
SOURCE OF LIFT...NOTABLE ISENTROPIC LIFT ACRS THE FRNTL BNDRY AS
WELL. TOTAL INSTABILITY IS LACKING...HOWEVER...WITH H70-H50 LAPSE
RATES BTWN 5.0-5.5C/KM.
THE DVLPG ERLY FLOW WILL PUSH THE FRNTL BNDRY BACK TO THE NW THRU
THE DAY...EVENTUALLY REACHING THE FL BIG BEND AFT SUNSET. AS ERLY
FLOW DEEPENS...DRIER AIR E OF THE BAHAMAS WILL FILTER INTO THE
REGION WITH H100-H70 MEAN RH VALUES FALLING BLO 70PCT ALONG THE
SPACE/TREASURE COAST BY 00Z. PRECIP COVERAGE WILL SHIFT TO THE N/W
THRU THE DAY. DEBRIS CLOUDS FROM EXISTING CONVECTION OVER THE FL
STRAITS MAY STABILIZE THE AIRMASS ALONG THE TREASURE COAST...NOTABLE
OUTFLOW BNDRY GENERATED BY CONVECTION OVER S FL MAY FURTHER
STABILIZE AIR ARND THE LAKE OKEECHOBEE REGION. ELSEWHERE...SFC
HEATING WILL BE SUFFICIENT TO ALLOW DIURNAL CONVECTION TO DVLP BY
EARLY AFTN. PRECIP MAINLY IN THE FORM OF SHRAS DUE TO THE WEAK LAPSE
RATES...TSTM COVERAGE SHOULD BE ISOLD AT BEST.
MRNG FCST PACKAGE LOOKS GOOD...BUT WILL CONVERT PRECIP TO A MORE
STRATIFORM NATURE OVER THE SRN CWA TO REFLECT LATEST PRECIP TREND.
&&
.AVIATION...
WINDS: THRU 27/00Z...N OF KMLB-KISM E/NE ARND 10KTS...S OF KMLB-KISM
E/SE ARND 10KTS. BTWN 27/00Z-27/04Z...BCMG E/NE AOB 5KTS ALL
SITES...CONTG THRU 27/12Z.
CIGS/VSBYS: THRU 26/17Z...PREVAILING VFR...VCNTY SHRA/TSRA COASTAL
SITES WITH BRIEF PDS OF MVFR CIGS/VSBYS N OF KMLB...NMRS SHRAS E OF
KPBI EXPECTED TO REMAIN OFFSHORE OR DISSIPATE S OF KSUA. BTWN
26/17Z-26/24Z...W OF KMLB-KOBE NMRS MVFR/SCT IFR SHRAS/ISOLD LIFR
TSRAS...E OF KMLB-KOBE SCT MVFR SHRAS/ISOLD IFR TSRAS...STORM MOTION
NW ARND 10KTS. BTWN 17/00Z-17/03Z...N OF KMLB-KOBE SCT MVFR
SHRAS/ISOLD IFR TSRAS...S OF KMLB-KOBE ISOLD MVFR SHRAS. AFT
17/03Z...ISOLD MVFR SHRAS COASTAL SITES...VFR INTERIOR SITES.
&&
.MARINE...
LONG ERLY FETCH OVER THE SW ATLC WILL PUSH A STUBBORN STATIONARY
FRONT FROM THE LAKE OKEECHOBEE REGION BACK INTO THE FL BIG BEND THRU
LATE EVNG. LIGHT TO GENTLE E/NE BREEZE N OF CAPE CANAVERAL WILL
GRADUALLY VEER TO THE E/SE AT 10-15KTS...S OF CAPE CANAVERAL E/SE
WINDS WILL INCREASE TO ARND 15KTS. LITTLE CHANGE IN WAVE HEIGHTS AS
THE ERLY FLOW PUSHES A 3FT SWELL INTO THE LCL ATLC...THOUGH WIND
CHOP WILL BECOME MORE NOTICEABLE BY SUNSET. SEAS 2-3FT NEARSHORE AND
3-4FT OFFSHORE...DOMINANT PDS ARND 8SEC. NMRS SHRAS/ISOLD TSTMS AS
MVG N/NW AS THE FRONT RETREATS.
&&
.HYDROLOGY...(PREV DISC)
ST JOHNS RIVER AT ASTOR REMAINS IN ACTION STAGE. BESIDES HEAVY RAIN
OVER THE REGION OVER THE PAST SEVERAL DAYS...THE NORTHERLY WIND
COMPONENT AND TIDES HAVE MADE CONTRIBUTIONS IN THE HIGH RIVER LEVELS
IN THE ASTOR AREA. THE NORTHERLY WIND COMPONENT WILL CONTINUE TO
VEER MORE EASTERLY TODAY BUT LEVELS EXPECTED TO REMAIN AT OR
SLIGHTLY BELOW ACTION STAGE FOR THE NEXT FEW DAYS.
OTHER AREA BEING CLOSELY MONITORED IS ON THE SHINGLE CREEK NEAR
CAMPBELL. LEVELS ON THE RIVER CONTINUE TO SLOWLY FALL...BUT THIS
AREA IS MORE SUSCEPTIBLE THAN THE ST JOHNS TO FASTER RISES OCCURRING
IF RAIN AMOUNTS OF 1-2" FALL OVER A LARGE AREA OF THE BASIN. WILL
CONTINUE TO MONITOR AND RUN LOCAL MODEL AS NEEDED OVER THE NEXT FEW
DAYS.
ELSEWHERE...ANY HEAVY RAINFALL ON ALREADY SATURATED GROUND MAY
AGGRAVATE ANY ONGOING STANDING WATER ISSUES AND LEAD TO ADDITIONAL
MINOR FLOODING.
&&
.CLIMATE...
VERO BEACH RECORDED 1.66 INCHES OF RAINFALL YESTERDAY WHICH WAS A
NEW RECORD RAINFALL FOR THE DATE.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
RADAR/IMPACT WX.......CRISTALDI
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1015 AM EDT FRI SEP 26 2014
.UPDATE (REST OF TODAY AND TONIGHT)...
14Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A HIGHLY AMPLIFIED AND
UNPROGRESSIVE NORTHERN STREAM FLOW OVER NORTH AMERICA. MAIN FLOW
ARRIVES WITHIN A DEEP TROUGH OVER THE CALIFORNIA COAST BEFORE
QUICKLY RIDGING WELL NORTH INTO CENTRAL CANADA. THE FLOW THEN
FLATTENS OUT DOWNSTREAM AND BECOMES MORE ZONAL BY THE TIME IT
REACHES THE CANADIAN MARITIMES. SOUTH OF THIS MAIN FLOW WE FIND A
WEAK SHORTWAVE DROPPING SOUTHEAST OUT OF NEW ENGLAND OVERTOP AN
UPPER RIDGE CENTERED OFF THE SOUTHEAST CONUS COAST. OUR FORECAST
REGION REMAINS ON THE VERY WESTERN PERIPHERY OF THIS RIDGE
CIRCULATION...ALTHOUGH THE 26/12Z KTBW SOUNDING PROFILE DOES NOT
SHOW MUCH CONSISTENCY WITH THE WIND DIRECTION THROUGH ANY DEPTH OF
THE COLUMN.
ONCE AGAIN WE HAVE STARTED THE DAY WITH A VERY SHALLOW STABLE LAYER
RESULTING IN AREAS OF STRATUS. THIS STABLE LAYER PER THE KTBW
SOUNDING IS MAYBE 1-2KFT THICK...AND WE SHOULD BE ABLE TO MIX IT OUT
BY LATE IN THE MORNING. AS ADVERTISED BY THE MODELS...THE PW HAS
BEEN RISING AND IS NOW OVER 2.2" AT KTBW...AND APPROACHING 2.4" AT
KMFL. AS WOULD BE EXPECTED WITH SUCH A MOIST PROFILE...LAPSE RATES
ARE FAIRLY POOR...GENERALLY IN THE VICINITY OF MOIST ADIABATIC
THROUGH MUCH OF THE COLUMN. THEREFORE...THE COLUMN IS VERY FAVORABLE
FOR CONVECTION...BUT UNFAVORABLE FOR SEVERE TYPE UPDRAFTS. THIS IS
NOT TO SAY THAT A FEW STRONGER STORMS ARE NOT POSSIBLE GIVEN PROPER
LOW LEVEL MOISTURE POOLING TO INCREASE THE CAPE POTENTIAL...
HOWEVER...OVERALL THESE TYPE OF STORMS SHOULD BE FEW AND FAR BETWEEN
TODAY. THE GREATER THREAT FROM TODAYS STORMS (AND WE DO THINK
OVERALL COVERAGE THROUGH THE AFTERNOON AND EARLY EVENING WILL BE ON
THE HIGH SIDE) WILL BE THE POTENTIAL FOR LOCALLY VERY HEAVY
RAINFALL. SOME SPOTS HAVE SEEN CONSIDERABLE RAINFALL ALREADY THIS
WEEK...AND WILL NEED TO BE WATCHED CLOSELY SHOULD ANOTHER HEAVY
RAINFALL EVENT OCCUR NEARBY. HIGHLANDS COUNTY IS ONE PLACE THAT WILL
NEED TO BE WATCHED AS FLOODING HAS ALREADY BEEN A FACTOR IN THE PAST
COUPLE OF DAYS.
AT THE SURFACE...PRESSURE GRADIENT IS PROVIDING A SHALLOW LAYER OF
NORTHEAST TO EAST FLOW BETWEEN A LARGE RIDGE OF HIGH PRESSURE OVER
THE DEEP SOUTH AND AN INVERTED TROUGH ALONG THE FLORIDA EAST COAST.
THIS TROUGH WILL BE MIGRATING WESTWARD ACROSS THE PENINSULA TODAY
AND ALONG WITH A FEEBLE SEA-BREEZE WILL PROVIDE THE FOCUS FOR
POTENTIALLY A LOT OF SHOWERS AND STORMS AFTER 18-20Z.
REGIONAL RADARS ARE QUIET ACROSS THE FORECAST AREA THIS MID-MORNING
AND EXPECT THINGS TO REMAIN QUIET FOR SEVERAL MORE HOURS. SO...NO
REAL CONCERNS FOR OUTDOOR ACTIVITIES INTO THE EARLY AFTERNOON.
THEREAFTER RAIN CHANCES WILL BE QUICKLY INCREASING. LOCAL AND
NATIONAL HIRES CONVECTION ALLOWING GUIDANCE ARE JUST ABOUT ALL
AGGRESSIVE WITH THE STORM COVERAGE DURING THE SECOND HALF OF THE
DAY. THE GENERAL EVOLUTION SHOWN THROUGH THE GUIDANCE SUITE IS
TYPICAL OF AN EASTERLY FLOW REGIME. SHOWERS AND STORMS WILL FIRST
BREAK OUT OVER THE SOUTHERN ZONES BY MID AFTERNOON AND THEN MIGRATE
NORTHWEST WITH TIME REACHING THE TAMPA BAY AND NATURE COAST ZONES
FOR THE LATE AFTERNOON OR EARLY EVENING TIME PERIOD. THIS IS STILL A
SUMMER-LIKE SCENARIO WHERE IT LIKELY WILL NOT RAIN FOR A LONG TIME
AT MOST SPOTS...BUT THAT MOST SPOTS WILL LIKELY SEE RAIN. RAINFALL
CHANCES RANGE FROM 40-50% UP AROUND CHIEFLAND TO 60-70% BY THE TIME
YOU REACH BROOKSVILLE AND ALL THE WAY SOUTH FROM THERE TO FORT MYERS
AND SEBRING.
FIRST PART OF THE NIGHT / EVENING HOURS SHOULD STILL SEE SOME SCT
STORMS ALONG THE I-75 CORRIDOR AND TOWARD THE COAST WITH THE
ACTIVITY SLOWLY MIGRATING OFFSHORE INTO THE EASTERN GULF. THE SECOND
HALF OF THE OVERNIGHT SHOULD BE MAINLY DRY OVER THE LAND ZONES WITH
CONTINUED SHOWERS/STORMS ONGOING OVER THE COASTAL WATERS. LOW
TEMPERATURES BY SUNRISE SATURDAY WILL BE IN THE LOWER 70S NORTH AND
LOWER TO MIDDLE 70S SOUTH. HAVE A GREAT FRIDAY AND KEEP THOSE
UMBRELLAS HANDY LATER TODAY.
&&
.AVIATION...
AN AREA OF LOWE STRATUS FROM KSRQ UP INTO THE TAMPA BAY TERMINALS IS
SHRINKING FAST THIS MID-MORNING AND EXPECT CONDITIONS TO RETURN TO
VFR FOR ALL STATION BY 15-16Z. APPEARS AS THOUGH STORMS WILL BE
QUITE ACTIVE LATER TODAY AND HAVE INCLUDED TEMPOS FOR THUNDER AT ALL
TERMINALS AFTER 19Z. STORMS MIGRATE OFF THE COAST WITHIN A FEW HOURS
OF SUNSET AND PREVAILING VFR IS THEN EXPECTED THROUGH THE REMAINDER
OF THE OVERNIGHT.
&&
.MARINE...
LITTLE CHANGE FROM YESTERDAY AS A SURFACE TROUGH REMAINS IN PLACE
OVER THE EASTERN GULF WATERS AND DEEP TROPICAL MOISTURE REMAINS OVER
THE AREA. SCATTERED TO NUMEROUS THUNDERSTORMS OVER THE FLORIDA EAST
COAST WILL MOVE SLOWLY WEST AND BE A THREAT TO THE COASTAL WATERS
TOWARD THE LATE AFTERNOON AND EVENING HOURS. LIGHT OFFSHORE WINDS
AGAIN TODAY WITH A MILD SEA BREEZE AFFECT FOR THE SECOND HALF OF THE
DAY. THE MAIN HAZARDS WILL CONTINUE TO BE HIGHER WINDS AND SEAS IN
THE VICINITY OF THUNDERSTORMS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 85 75 88 76 / 70 40 60 40
FMY 86 75 88 74 / 70 30 50 20
GIF 86 74 88 74 / 60 20 50 20
SRQ 86 75 88 74 / 70 50 60 40
BKV 86 73 88 72 / 60 30 60 40
SPG 86 77 87 77 / 70 50 60 40
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/AVIATION...MROCZKA
MARINE...DOUGHERTY
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
955 AM EDT Fri Sep 26 2014
.Near Term [Today]...
The 8 am EDT regional surface analysis showed a large area of high
pressure across the Southeast, and a weak, quasi-stationary front
across central FL and off the Southeast coast. Vapor imagery and
upper air data showed a weak flow pattern over our forecast area,
between a ridge in the western Atlantic and a broad trough across
much of the central CONUS. Precip Water values were still below
average for much of our region, but they were gradually increasing
from the southeast. Like yesterday, a large deck of low clouds
enshrouded our forecast area, though there were a few breaks here
and there. We think that there will be just enough sunlight for it
to be slightly warmer this afternoon than yesterday, with highs
from the mid 80s in north FL to around 80 around Dothan and
Albany. Rain chances will primarily be limited to our north FL
zones (around Cross City), where there is more deep layer
moisture.
&&
.Aviation...
[Through 12Z Saturday]...MVFR to occasionally IFR cigs were
affecting all of our terminals this morning. There is good
agreement among the MOS, SREF, and HRRR in a gradual lifting of
these cigs through the day, possibly reaching VFR by mid to late
afternoon. However, a return to low cigs is likely overnight
(though the various NWP guidance differs on just how low).
&&
.Prev Discussion [337 AM EDT]...
.Short Term [Tonight Through Sunday]...
Deep moisture will continue to increase through the short term as
the deep layer flow turns more southeasterly and then southerly by
Sunday ahead of an upper trough. There is good agreement amongst
the model guidance on precipitable water values rising to well
above 2 inches across the area by Saturday and especially on
Sunday. With the approach of the upper trough on Sunday, a weak
surface low is likely to develop along the Gulf coast. These
factors point to increasing rain chances from south to north this
weekend with the highest chances on Sunday when some heavy
rainfall amounts could occur. The most likely area for heavy
rainfall appears to be along the Florida panhandle coast closest
to the better forcing from the upper trough on Sunday, and heavy
rain wording was inserted into this area. Afternoon temperatures
will be a bit below normal with all of the cloud cover expected.
.Long Term [Sunday Night Through Friday]...
Deep moisture will be in place through Monday as the inverted
surface trough interacts with an upper trough over the central
Gulf Coast. This should result in elevated rain chances continuing
into Monday, with locally heavy rainfall possible given
precipitable water values above 2 inches. Things should begin to
dry out by Monday night or Tuesday as the upper energy shears out
to the northeast. The global guidance differs in the timing on
when the deep moisture moves out, so have left some low end PoPs
in the forecast for much of the forecast period. With the tropical
airmass for the first part of the period and no significant
airmass change expected behind this system, expect temperatures to
run near or just above normal into the middle of next week.
.Marine...
Northeasterly flow will continue through tonight before shifting
to easterly on Saturday and southeasterly Saturday night into
Sunday. Conditions will likely be at or near exercise caution
levels this weekend before winds weaken early next week.
.Fire Weather...
As we transition to a very wet pattern, there will be no fire
weather concerns through at least early next week.
.Hydrology...
General rainfall amounts of 1 to 2 inches are likely across the
forecast area through Monday, except 2 to 3 inches with locally
higher amounts along the panhandle coast. These amounts are not
expected to result in any river flooding due to low flows from the
recent dry summer. However, isolated instances of flash flooding
cannot yet be ruled out for Sunday, mainly along the panhandle
coast. It is too soon to consider any watches, but this trend will
have to be monitored.
&&
.Preliminary Point Temps/PoPs...
Tallahassee 82 70 86 72 86 / 10 10 50 40 70
Panama City 81 71 84 74 86 / 10 10 60 70 80
Dothan 79 67 84 70 84 / 10 10 40 40 70
Albany 80 67 85 70 85 / 20 10 40 40 60
Valdosta 81 69 86 70 86 / 10 20 50 40 60
Cross City 84 71 86 71 87 / 40 40 60 40 60
Apalachicola 81 73 84 75 83 / 10 30 70 70 70
&&
.TAE Watches/Warnings/Advisories...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...FOURNIER
SHORT TERM...DVD
LONG TERM...CAMP
AVIATION...FOURNIER
MARINE...DVD
FIRE WEATHER...HARRIGAN
HYDROLOGY...DVD
AREA FORECAST DISCUSSION
NWS MIAMI FL
744 AM EDT FRI SEP 26 2014
.AVIATION...
A WEAK TROUGH WILL KEEP UNSETTLED WEATHER ACROSS SOUTH FLORIDA
THROUGH THE TAF PERIOD. SHOWERS WILL MOVE WEST, OFF THE ATLANTIC,
AND BRING SHOWERS AND SOME THUNDERSTORMS TO THE AREA BY MID
MORNING AND LAST INTO THE AFTERNOON. THEY ARE EXPECTED TO MOVE
FURTHER INLAND SOMETIME IN THE MID AFTERNOON, SO THE VCTS IN THE
TAFS MAY BE ABLE TO END A COUPLE OF HOURS EARLIER, DEPENDING HOW
FAST THEY DO MOVE INLAND. OTHERWISE, VFR CONDITIONS THROUGH THE
TAF PERIODS, WITH BRIEF IFR POSSIBLE UNDER HEAVY SHOWERS AND
THUNDERSTORMS.
&&
.PREV DISCUSSION... /ISSUED 246 AM EDT FRI SEP 26 2014/
SHORT TERM (TODAY-SUNDAY)...
ATLANTIC RIDGE HAS BEGUN TO BUILD BACK TO THE WEST ACROSS THE
FLORIDA PENINSULA WITH A WEAK SURFACE INVERTED TROUGH LOCATED ALONG
THE EAST COAST. THIS HAS CONTINUED AN ACTIVE PATTERN OF OVERNIGHT
CONVECTION OVER THE ATLANTIC WATERS AND ALONG THE IMMEDIATE EAST
COAST WITH SLOW MOVEMENT TO THE NORTH-NORTHWEST. THERE IS A LITTLE
UNCERTAINTY AS TO THE PATTERN OF DEVELOPMENT FOR THE REST OF
TODAY AS THE GFS DOES NOT DRY THE ATMOSPHERE AS IN PAST RUNS
KEEPING THE PWAT CLOSE TO 2" AND WITH A MUCH SHALLOWER EASTERLY
FLOW. THIS WOULD TRANSLATE TO A CONTINUATION OF POSSIBLE LOCALLY
HEAVY RAINS JUST ABOUT ANYWHERE. HOWEVER, THE ECMWF IS SHOWING THE
DEEPER EASTERLY FLOW AND WITH PWAT LOWERING TO AROUND 1.75". THE
00Z MFL SOUNDING SHOWED THE DEEP SOUTHEAST FLOW IN PLACE AT THAT
TIME AND SEE LITTLE REASON TO BELIEVE MUCH WOULD CHANGE IN THE
OVERNIGHT PERIOD. FOR THIS REASON, WOULD TEND TO LEAN TOWARDS THE
GFS SOLUTION. IN THIS THINKING, THE HRRR DOES KEEP THE EAST COAST
RATHER ACTIVE THROUGH MUCH OF THE MORNING BEFORE SHIFTING INLAND
DURING THE EARLY AFTERNOON. THE SATELLITE DERIVED PWAT IMAGERY
DOES SHOW SOME DRYING HEADED OUR WAY BUT IT IS NOT SIGNIFICANT WITH
LEADING EDGE STILL ROUGHLY 250 MILES TO OUR EAST. SO AM A LITTLE
RELUCTANT TO SAY AT THIS TIME MUCH IN THE WAY OF LOWER POPS BUT IT
WOULD APPEAR THAT THE MAIN THREAT FOR HEAVIER RAINS WILL BE DURING
THE MORNING NEAR THE EAST COAST AND ACROSS THE INTERIOR AND WEST
COAST REGION DURING THE AFTERNOON PERIOD.
THE ATLANTIC RIDGE WILL REMAIN THE DOMINANT FEATURE OVER THE WEEKEND
WITH SOME SLOW DRYING OCCURRING IN THE UPPER LEVELS. A WEAK SURFACE
RIDGE WILL ALSO DEVELOP NORTH OF THE REGION AS THE WEAK TROUGH FADES
AWAY WITH LACK OF UPPER SUPPORT. EVEN THOUGH SOME DRYING WILL OCCUR,
PWAT`S WILL BE AT NORMAL LEVELS FOR LATE SEPTEMBER NEAR 1.75". THE
GFS KEEPS THE SOUTHEASTERLY FLOW RATHER SHALLOW ON SATURDAY BUT THEN
DEEPENS IT ON SUNDAY. SO THE PATTERN COULD STILL FAVOR ATLANTIC
ACTIVITY DURING THE NIGHTTIME HOURS PUSHING ONSHORE ALONG THE EAST
COAST AND THEN FAVORING INTERIOR AND WEST COAST AREAS EACH AFTERNOON.
LONG TERM (MONDAY-THURSDAY)...
GLOBAL MODELS CONTINUE TO BE IN GOOD AGREEMENT NEXT WEEK IN
DEVELOPING CYCLONIC FLOW ACROSS MUCH OF THE NATION WITH A STRONG
MID/UPPER LEVEL TROUGH MOVING THROUGH THE SOUTHEAST STATES EARLY IN
THE WEEK. THE CYCLONIC FLOW PATTERN WILL SUPPRESS THE UPPER RIDGE
TO OUR SOUTH AND THIS WILL PLACE SOUTH FLORIDA IN A WESTERLY
STEERING FLOW FOR MUCH OF NEXT WEEK WITH PWAT`S RUNNING IN THE
1.75-2" RANGE. SO THE EAST COAST METRO AREAS COULD EXPERIENCE SOME
THREAT FOR LOCALLY HEAVY RAINS ONCE AGAIN ESPECIALLY EARLY IN THE
PERIOD.
MARINE...
A LIGHT TO MODERATE EAST WIND FLOW WILL CONTINUE THROUGH THE
WEEKEND. THE FLOW WILL THEN VEER TO THE SOUTHWEST EARLY NEXT WEEK
AS THE HIGH PRESSURE GETS SUPPRESSED TO THE SOUTH OF THE LOCAL
WATERS. SEAS THROUGH THE PERIOD WILL GENERALLY BE 2-3 FEET IN THE
ATLANTIC WITH 2 FEET OR LESS OVER THE GULF WATERS. SHOWERS AND
THUNDERSTORMS CAN ALSO BE EXPECTED EACH DAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 78 86 78 / 60 20 30 20
FORT LAUDERDALE 87 79 88 79 / 50 20 30 30
MIAMI 87 78 88 77 / 50 20 30 20
NAPLES 89 76 90 76 / 70 30 60 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...30/KOB
LONG TERM....30/KOB
AVIATION...13/SI
AREA FORECAST DISCUSSION
NWS MIAMI FL
246 AM EDT FRI SEP 26 2014
.SHORT TERM (TODAY-SUNDAY)...
ATLANTIC RIDGE HAS BEGUN TO BUILD BACK TO THE WEST ACROSS THE
FLORIDA PENINSULA WITH A WEAK SURFACE INVERTED TROUGH LOCATED ALONG
THE EAST COAST. THIS HAS CONTINUED AN ACTIVE PATTERN OF OVERNIGHT
CONVECTION OVER THE ATLANTIC WATERS AND ALONG THE IMMEDIATE EAST
COAST WITH SLOW MOVEMENT TO THE NORTH-NORTHWEST. THERE IS A LITTLE
UNCERTAINTY AS TO THE PATTERN OF DEVELOPMENT FOR THE REST OF
TODAY AS THE GFS DOES NOT DRY THE ATMOSPHERE AS IN PAST RUNS
KEEPING THE PWAT CLOSE TO 2" AND WITH A MUCH SHALLOWER EASTERLY
FLOW. THIS WOULD TRANSLATE TO A CONTINUATION OF POSSIBLE LOCALLY
HEAVY RAINS JUST ABOUT ANYWHERE. HOWEVER, THE ECMWF IS SHOWING THE
DEEPER EASTERLY FLOW AND WITH PWAT LOWERING TO AROUND 1.75". THE
00Z MFL SOUNDING SHOWED THE DEEP SOUTHEAST FLOW IN PLACE AT THAT
TIME AND SEE LITTLE REASON TO BELIEVE MUCH WOULD CHANGE IN THE
OVERNIGHT PERIOD. FOR THIS REASON, WOULD TEND TO LEAN TOWARDS THE
GFS SOLUTION. IN THIS THINKING, THE HRRR DOES KEEP THE EAST COAST
RATHER ACTIVE THROUGH MUCH OF THE MORNING BEFORE SHIFTING INLAND
DURING THE EARLY AFTERNOON. THE SATELLITE DERIVED PWAT IMAGERY
DOES SHOW SOME DRYING HEADED OUR WAY BUT IT IS NOT SIGNIFICANT WITH
LEADING EDGE STILL ROUGHLY 250 MILES TO OUR EAST. SO AM A LITTLE
RELUCTANT TO SAY AT THIS TIME MUCH IN THE WAY OF LOWER POPS BUT IT
WOULD APPEAR THAT THE MAIN THREAT FOR HEAVIER RAINS WILL BE DURING
THE MORNING NEAR THE EAST COAST AND ACROSS THE INTERIOR AND WEST
COAST REGION DURING THE AFTERNOON PERIOD.
THE ATLANTIC RIDGE WILL REMAIN THE DOMINANT FEATURE OVER THE WEEKEND
WITH SOME SLOW DRYING OCCURRING IN THE UPPER LEVELS. A WEAK SURFACE
RIDGE WILL ALSO DEVELOP NORTH OF THE REGION AS THE WEAK TROUGH FADES
AWAY WITH LACK OF UPPER SUPPORT. EVEN THOUGH SOME DRYING WILL OCCUR,
PWAT`S WILL BE AT NORMAL LEVELS FOR LATE SEPTEMBER NEAR 1.75". THE
GFS KEEPS THE SOUTHEASTERLY FLOW RATHER SHALLOW ON SATURDAY BUT THEN
DEEPENS IT ON SUNDAY. SO THE PATTERN COULD STILL FAVOR ATLANTIC
ACTIVITY DURING THE NIGHTTIME HOURS PUSHING ONSHORE ALONG THE EAST
COAST AND THEN FAVORING INTERIOR AND WEST COAST AREAS EACH AFTERNOON.
.LONG TERM (MONDAY-THURSDAY)...
GLOBAL MODELS CONTINUE TO BE IN GOOD AGREEMENT NEXT WEEK IN
DEVELOPING CYCLONIC FLOW ACROSS MUCH OF THE NATION WITH A STRONG
MID/UPPER LEVEL TROUGH MOVING THROUGH THE SOUTHEAST STATES EARLY IN
THE WEEK. THE CYCLONIC FLOW PATTERN WILL SUPPRESS THE UPPER RIDGE
TO OUR SOUTH AND THIS WILL PLACE SOUTH FLORIDA IN A WESTERLY
STEERING FLOW FOR MUCH OF NEXT WEEK WITH PWAT`S RUNNING IN THE
1.75-2" RANGE. SO THE EAST COAST METRO AREAS COULD EXPERIENCE SOME
THREAT FOR LOCALLY HEAVY RAINS ONCE AGAIN ESPECIALLY EARLY IN THE
PERIOD.
&&
.MARINE...
A LIGHT TO MODERATE EAST WIND FLOW WILL CONTINUE THROUGH THE
WEEKEND. THE FLOW WILL THEN VEER TO THE SOUTHWEST EARLY NEXT WEEK
AS THE HIGH PRESSURE GETS SUPPRESSED TO THE SOUTH OF THE LOCAL
WATERS. SEAS THROUGH THE PERIOD WILL GENERALLY BE 2-3 FEET IN THE
ATLANTIC WITH 2 FEET OR LESS OVER THE GULF WATERS. SHOWERS AND
THUNDERSTORMS CAN ALSO BE EXPECTED EACH DAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 78 86 78 / 60 20 30 20
FORT LAUDERDALE 87 79 88 79 / 50 20 30 30
MIAMI 87 78 88 77 / 50 20 30 20
NAPLES 89 76 90 76 / 70 30 60 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...30/KOB
LONG TERM....30/KOB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
357 PM EDT FRI SEP 26 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 356 PM EDT FRI SEP 26 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH NEAR
THE WEST COAST AND A PROMINENT RIDGE ACROSS THE PLAINS INTO NRN
ONTARIO. AT THE SFC...WEAK SRLY FLOW WAS OBSERVED THROUGH WI AND
UPPER MI BETWEEN HIGH PRES OVER LAKE HURON AND A TROUGH THROUGH THE
WRN PLAINS. VIS LOOP INDICATED SCT CU UPSTREAM OVER THE UPPER MS
VALLEY AS LOW LEVEL MOISTURE INCREASES. OTHERWISE...COMPLETELY CLEAR
SKIES PREVAILED ACROSS UPPER MICHIGAN. DEWPOINTS WERE GENERALLY IN
THE LOWER 50S...WITH SOME HIGHER VALUES IN THE MID 50S OVER THE EAST
DOWNWIND OF LAKE MICHIGAN.
TONIGHT...WITH THE UPPER AND SFC RIDGE NEARLY STATIONARY OVER THE
AREA...EXPECT FOG TO REDEVELOP IN AREAS SIMILAR TO THU NIGHT...WITH
THE LOWEST VISIBILITIES OVER THE CNTRAL AND EAST AND ESPECIALLY
NEAR LAKE MICHIGAN.
SAT...A MID LEVEL TROUGH AND ASSOCIATED SFC LOW WILL MOVE THROUGH
FAR NRN ONTARIO TO SRN HUDSON BAY DRAGGING A COLD FRONT TO NEAR
CYPL. SRLY FLOW AHEAD OF FRONT WILL KEEP THE WARM AIR ACROSS THE
CWA. AFTER ANY MORNING FOG BURNS OFF...SUNNY SKIES WILL AGAIN
DOMINATE THE AREA. FCST SOUNDINGS SUGGEST THAT MIXING TO AROUND 850
MB (TEMPS AROUND 14C) WILL SUPPORT MAX READINGS INT THE UPPER 70S TO
NEAR 80.
&
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 332 PM EDT FRI SEP 26 2014
THE RELATIVELY WARM STREAK SEEN OVER THE PAST WEEK WILL COME TO AN
END EARLY NEXT WEEK AS A MORE PROGRESSIVE PATTERN DEVELOPS OVER THE
CENTRAL U.S.
SATURDAY NIGHT...WEAK MID-LEVEL RIDGING WILL BE OVER THE REGION AT
THE BEGINNING OF THE PERIOD AS A SLOW MOVING COLD FRONT STRETCHES
FROM NORTH DAKOTA TO HUDSON BAY. THIS FRONT WILL BE THE MAIN PLAYER
IN PRECIP CHANCES EARLY NEXT WEEK.
WITH THE LIGHT SOUTHERLY FLOW AND A CONTINUED INCREASE OF SFC
MOISTURE SATURDAY NIGHT...FOG WILL BE POSSIBLE ONCE AGAIN ACROSS THE
INTERIOR CENTRAL AND EAST. HOWEVER...DAYTIME MIXING ON SATURDAY MAY
LOWER DEWPOINTS FARTHER THAN MODELS ARE INDICATING. THIS LIKELY WILL
NOT BE REALIZED UNTIL SATURDAY AFTERNOON...SO WILL CONTINUE WITH THE
MENTION OF AREAS OF FOG.
SUNDAY...THE COLD FRONT WILL INCH CLOSER TO THE REGION ON
SUNDAY...BUT SHOULD HOLD OFF REACHING THE KEWEENAW UNTIL SUNDAY
EVENING. SUNDAY WILL BE THE LAST DAY IN THIS WARM STRETCH. WITH 850
HPA TEMPS STILL 12 TO 14C ACROSS THE CWA...HIGHS WILL BE WELL INTO
THE 70S FOR MUCH OF THE AREA. THESE VALUES ARE 15-20F ABOVE AVERAGES
IN THE LOW 60S THIS TIME OF YEAR. SEVERAL MODELS ARE INDICATING SOME
AFTERNOON DIURNAL SHOWERS ALONG THE LAKE BREEZE NORTH-CENTRAL. AM
STILL HAVING A HARD TIME BUYING INTO THIS AS LOW-LEVEL MOISTURE
APPEARS TO BE OVERDONE BY THE MODELS AND DEEP-LAYER MOISTURE IS
MARGINAL. DAYTIME MIXING ALONG WITH QUICKLY DIMINISHING
EVAPOTRANSPIRATION THIS TIME OF YEAR SHOULD LIMIT THE OVERALL SFC
MOISTURE AND INSTABILITY.
SUNDAY NIGHT AND MONDAY...THE COLD FRONT WILL ARRIVE ACROSS
THE KEWEENAW EARLY SUNDAY EVENING AND CONTINUE SINKING SOUTHWARD
THROUGH THE NIGHT. A DECENT AMOUNT OF LINEAR FORCING WILL BE
AVAILABLE THROUGH LOW-LEVEL FGEN...MID-LEVEL Q-VECTOR CONV...AND THE
RIGHT ENTRANCE OF AN UPPER JET. THIS SUGGESTS CONTINUING WITH LIKELY
POPS FOR MUCH OF THE AREA. TIMING OF THE PRECIP REMAINS A
SIGNIFICANT CHALLENGE DUE TO MODEL DIFFERENCE AND INCONSISTENCY. THE
12Z NAM SOLUTION HAS COME IN MUCH DIFFERENT FROM PREVIOUS RUNS AND
OTHER MODELS. THE SLOWER PROGRESSION OF THE TROUGH BY THE NAM DELAYS
PRECIP UNTIL LATE SUNDAY NIGHT. WITH THAT SAID MONDAYS FORECAST
BECOMES QUITE TRICKY AS THE TEMP AND PRECIP FORECAST HINGES ON HOW
FAR SOUTH THE FRONT MAKES IT SUNDAY NIGHT. A FASTER SOLUTION /ECMWF/
WOULD RESULT IN A MUCH COOLER DAY WITH SHOWERS FOR THE ENTIRE CWA. A
SLOWER SOLUTION /NAM/ WOULD ALLOW DIABATIC HEATING ACROSS THE
SOUTH-CENTRAL TO STALL THE FRONT EVEN MORE...BRINGING MUCH COOLER
CONDITIONS AND SHOWERS TO JUST THE NORTHERN CWA. HAVE OPTED TO TREND
TOWARD THE SLOWER IDEA AS EVEN THE 12Z GFS SLOWED THE PROGRESSION OF
THE FRONT. OVERALL...CONFIDENCE IS FAIRLY HIGH ON THE LIKELIHOOD OF
RAIN...BUT LOW ON THE TIMING.
MONDAY NIGHT AND TUESDAY...MID-LEVEL RIDGING WILL BEGIN BUILDING
ACROSS THE UPPER GREAT LAKES MONDAY NIGHT AS THE SFC FRONT CONTINUES
SSE OUT OF THE AREA. LOW-LEVEL MOISTURE WILL LINGER WELL INTO
TUESDAY WITH WEAK NE FLOW OFF LAKE SUPERIOR. THIS SHOULD LEAD TO AT
LEAST SOME UPSLOPE SHOWERS/DRIZZLE CENTRAL AND EAST ALONG LAKE
SUPERIOR THROUGH MONDAY NIGHT. THEN...AN INVERSION AROUND 3KFT
COMBINED WITH THE WEAKENING IMPACT OF THE SUN FOR MIXING...MAY KEEP
THE AREA SOCKED IN WITH LOW CLOUDS THROUGHOUT THE DAY TUESDAY. HAVE
THUS CONTINUED THE TREND OF LOWERING HIGH TEMPS FOR TUESDAY...WITH
HIGHS GENERALLY IN THE 50S CWA-WIDE. ALSO...WITH LOW-LEVEL HIGH
PRESSURE SHIFTING EASTWARD NORTH OF LAKE SUPERIOR AND INITIATING
RETURN SOUTHERLY FLOW ACROSS THE AREA...IT MAY EVEN BE DIFFICULT TO
COMPLETELY RID THE AREA OF LOW CLOUDS BY TUESDAY NIGHT.
WEDNESDAY THROUGH FRIDAY...DEEP TROUGHING OVER THE NORTHERN ROCKIES
WILL BE LIFTING NORTHEASTWARD AS MID-LEVEL RIDGING OVER THE UPPER
GREAT LAKES SHIFTS EASTWARD. MODEL GUIDANCE IS IN FAIRLY GOOD
AGREEMENT WITH THE SYNOPTIC PATTERN...BUT DIFFERS SOMEWHAT WITH THE
OVERALL INTENSITY OF THE TROUGH AND ASSOCIATED SFC LOW. ATTM...A
COLD FRONT IS PROGGED TO SLOWLY TRACK EASTWARD ACROSS THE CWA
WEDNESDAY MORNING THROUGH THURSDAY NIGHT AS THE SFC LOW MOVES
NORTHWARD OVER MANITOBA. WILL MAINTAIN CONSENSUS POPS...WITH AN
EMPHASIS FOR BETTER CHANCES ON THURSDAY WITH THE ARRIVAL OF
UPPER-LEVEL SUPPORT FROM THE RIGHT ENTRANCE OF A JET.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 130 PM EDT FRI SEP 26 2014
WITH PLENTY OF DRY AIR ASSOCIATED WITH A HIGH PRESSURE RIDGE OVER
THE UPPER GREAT LAKES...EXPECT VFR CONDITIONS AND GENERALLY LIGHT
WINDS AT ALL SITES. KCMX SHOULD SEE AN EASTERLY LAKE BREEZE AFFECT THE
SITE IN THE AFTERNOON. FOG IS POSSIBLE AT ALL THREE SITES AGAIN
TONIGHT...WITH THE GREATEST CHANCE OF MVFR VSBY OR LOWER AT
KSAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 356 PM EDT FRI SEP 26 2014
A HIGH PRESSURE CENTERED OVER THE LOWER GREAT LAKES WILL REMAIN
STATIONARY THROUGH SUNDAY WHILE STRETCHING A RIDGE NORTHWEST ACROSS
THE UPPER GREAT LAKES. THIS WILL LEAD TO LIGHT SOUTHERLY FLOW
(BELOW 20KTS) INTO SUNDAY. A COLD FRONT DROPPING SOUTHEAST ACROSS
THE UPPER GREAT LAKES SUNDAY NIGHT INTO MONDAY MORNING WILL SHIFT
WINDS AROUND TO THE NORTHEAST WITH GUSTS TO 30KTS. HIGH PRESSURE
CENTERED OVER EASTERN CANADA WILL THEN PLACE A RIDGE OVER THE UPPER
GREAT LAKES FOR MONDAY NIGHT AND TUESDAY...LEADING TO DIMINISHING
WINDS.
WITH MORE MOIST AIR BEGINNING TO WORK NORTH OVER LAKE
SUPERIOR...THERE IS THE POTENTIAL FOR PATCHY/AREAS OF FOG OVER
NORTHERN PORTIONS OF LAKE SUPERIOR OVER THE NEXT COUPLE OF DAYS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
333 PM EDT FRI SEP 26 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM EDT FRI SEP 26 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS DATA SHOW AN UPPER RIDGE OVER
MUCH OF THE CENTRAL CONUS WHILE A DEEP UPPER TROUGH IS COMING ON
SHORE OVER THE WESTERN COAST OF THE CONUS. UNDER THE UPPER
RIDGE...THE REMNANTS OF THE UPPER LEVEL DISTURBANCE THAT AFFECTED
THE AREA 24 HOURS AGO IS SPINNING OVER THE MID MISSISSIPPI VALLEY.
AT THE SURFACE...A 1026MB HIGH IS STATIONARY OVER THE LOWER GREAT
LAKES AND STRETCHES A 1023MB RIDGE OVER THE UPPER GREAT LAKES
REGION. THIS RIDGE IS PROVIDING A SIGNIFICANT AMOUNT OF DRY AIR
BETWEEN 850-500MB AS SEEN ON THE 00Z KGRB/KAPX SOUNDINGS. THIS HAS
LED TO CLEAR SKIES OVER MUCH OF UPPER MICHIGAN EARLY THIS
MORNING...BUT SOME LINGERING LOW LEVEL MOISTURE REMAINS ON THE
NORTHWEST EDGE OF THE SURFACE RIDGE OVER NORTHERN LAKE SUEPRIOR AND
NORTHWEST ONTARIO. THESE CLOUDS HAVE BEEN GRADUALLY DISSIPATING
UNDER THE SUBSIDENCE ALOFT AND THE INFLUX OF DRIER AIR FROM THE
SOUTH-SOUTHWEST FLOW BETWEEN 925-850MB AND EXPECT THAT TO CONTINUE
THROUGH THE DAY TODAY. BACK TO UPPER MICHIGAN...THE CLEAR SKIES AND
LIGHT WINDS HAS LED TO PATCHY RADIATIONAL FOG TO DEVELOP OVER
PARTS OF THE CENTRAL/EASTERN U.P. AREAS NEAR LAKE MICHIGAN HAVE BEEN
SEEN FOG AS LOW AS 1/4MI THUS FAR AND EXPECT THAT AREA OF LOWER
VISIBILITIES TO EXPAND THROUGH SUNRISE. WILL MONITOR FOG TRENDS
AND IF THE LOWER VISIBILITIES BECOME MORE WIDESPREAD WILL ISSUE AN
SPS TO ADDRESS THE REDUCED VISIBILITIES INTO THE MORNING HOURS.
EXPECT THE FOG TO BURN OFF BETWEEN 14-15Z BASED OFF TIMING FROM A
COUPLE DAYS AGO AND GOES-R CLOUD THICKNESS DATA NEARING 900FT OVER
THE EAST LEADING TO A DISSIPATION TIME OF 2-2.5HRS AFTER SUNRISE.
AFTER THE FOG BURNS OFF...IT SHOULD BE A WONDERFULL EARLY FALL DAY
TO TAKE IN THE FALL COLORS. EXPECT SUNNY SKIES OVER MUCH OF THE
AREA...ALTHOUGH WITH THE NORTHWEST THIRD STILL NEAR SOME OF THE
DEPARTING 925-850MB MOISTURE WOULD EXPECT SOME DIURNAL CU TO
DEVELOP IN THAT AREA DURING PEAK HEATING. WITH PLENTY OF SUNSHINE
AND MIXING TO AROUND 875MB...EXPECT MOST AREAS TO BE IN THE MID 70S
FOR HIGHS TODAY. LIGHT SOUTHERLY FLOW WILL LEAD TO SLIGHTLY COOLER
VALUES NEAR LAKE MICHIGAN AND SLIGHTLY WARMER VALUES IN THE
DOWNSLOPE AREAS NEAR LAKE SUPERIOR.
WITH THE UPPER/SURFACE RIDGE NEARLY STATIONARY OVER THE AREA FOR
THE NEXT 24HRS...EXPECT FOG TO MAKE AN APPEARANCE ACROSS THE AREA
AGAIN TONIGHT. COVERAGE WILL LIKELY BE SIMILAR ACROSS THE
AREA...WITH THE LOWEST VISIBILITIES OVER THE CENTRAL/EAST AND
ESPECIALLY NEAR LAKE MICHIGAN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 332 PM EDT FRI SEP 26 2014
THE RELATIVELY WARM STREAK SEEN OVER THE PAST WEEK WILL COME TO AN
END EARLY NEXT WEEK AS A MORE PROGRESSIVE PATTERN DEVELOPS OVER THE
CENTRAL U.S.
SATURDAY NIGHT...WEAK MID-LEVEL RIDGING WILL BE OVER THE REGION AT
THE BEGINNING OF THE PERIOD AS A SLOW MOVING COLD FRONT STRETCHES
FROM NORTH DAKOTA TO HUDSON BAY. THIS FRONT WILL BE THE MAIN PLAYER
IN PRECIP CHANCES EARLY NEXT WEEK.
WITH THE LIGHT SOUTHERLY FLOW AND A CONTINUED INCREASE OF SFC
MOISTURE SATURDAY NIGHT...FOG WILL BE POSSIBLE ONCE AGAIN ACROSS THE
INTERIOR CENTRAL AND EAST. HOWEVER...DAYTIME MIXING ON SATURDAY MAY
LOWER DEWPOINTS FARTHER THAN MODELS ARE INDICATING. THIS LIKELY WILL
NOT BE REALIZED UNTIL SATURDAY AFTERNOON...SO WILL CONTINUE WITH THE
MENTION OF AREAS OF FOG.
SUNDAY...THE COLD FRONT WILL INCH CLOSER TO THE REGION ON
SUNDAY...BUT SHOULD HOLD OFF REACHING THE KEWEENAW UNTIL SUNDAY
EVENING. SUNDAY WILL BE THE LAST DAY IN THIS WARM STRETCH. WITH 850
HPA TEMPS STILL 12 TO 14C ACROSS THE CWA...HIGHS WILL BE WELL INTO
THE 70S FOR MUCH OF THE AREA. THESE VALUES ARE 15-20F ABOVE AVERAGES
IN THE LOW 60S THIS TIME OF YEAR. SEVERAL MODELS ARE INDICATING SOME
AFTERNOON DIURNAL SHOWERS ALONG THE LAKE BREEZE NORTH-CENTRAL. AM
STILL HAVING A HARD TIME BUYING INTO THIS AS LOW-LEVEL MOISTURE
APPEARS TO BE OVERDONE BY THE MODELS AND DEEP-LAYER MOISTURE IS
MARGINAL. DAYTIME MIXING ALONG WITH QUICKLY DIMINISHING
EVAPOTRANSPIRATION THIS TIME OF YEAR SHOULD LIMIT THE OVERALL SFC
MOISTURE AND INSTABILITY.
SUNDAY NIGHT AND MONDAY...THE COLD FRONT WILL ARRIVE ACROSS
THE KEWEENAW EARLY SUNDAY EVENING AND CONTINUE SINKING SOUTHWARD
THROUGH THE NIGHT. A DECENT AMOUNT OF LINEAR FORCING WILL BE
AVAILABLE THROUGH LOW-LEVEL FGEN...MID-LEVEL Q-VECTOR CONV...AND THE
RIGHT ENTRANCE OF AN UPPER JET. THIS SUGGESTS CONTINUING WITH LIKELY
POPS FOR MUCH OF THE AREA. TIMING OF THE PRECIP REMAINS A
SIGNIFICANT CHALLENGE DUE TO MODEL DIFFERENCE AND INCONSISTENCY. THE
12Z NAM SOLUTION HAS COME IN MUCH DIFFERENT FROM PREVIOUS RUNS AND
OTHER MODELS. THE SLOWER PROGRESSION OF THE TROUGH BY THE NAM DELAYS
PRECIP UNTIL LATE SUNDAY NIGHT. WITH THAT SAID MONDAYS FORECAST
BECOMES QUITE TRICKY AS THE TEMP AND PRECIP FORECAST HINGES ON HOW
FAR SOUTH THE FRONT MAKES IT SUNDAY NIGHT. A FASTER SOLUTION /ECMWF/
WOULD RESULT IN A MUCH COOLER DAY WITH SHOWERS FOR THE ENTIRE CWA. A
SLOWER SOLUTION /NAM/ WOULD ALLOW DIABATIC HEATING ACROSS THE
SOUTH-CENTRAL TO STALL THE FRONT EVEN MORE...BRINGING MUCH COOLER
CONDITIONS AND SHOWERS TO JUST THE NORTHERN CWA. HAVE OPTED TO TREND
TOWARD THE SLOWER IDEA AS EVEN THE 12Z GFS SLOWED THE PROGRESSION OF
THE FRONT. OVERALL...CONFIDENCE IS FAIRLY HIGH ON THE LIKELIHOOD OF
RAIN...BUT LOW ON THE TIMING.
MONDAY NIGHT AND TUESDAY...MID-LEVEL RIDGING WILL BEGIN BUILDING
ACROSS THE UPPER GREAT LAKES MONDAY NIGHT AS THE SFC FRONT CONTINUES
SSE OUT OF THE AREA. LOW-LEVEL MOISTURE WILL LINGER WELL INTO
TUESDAY WITH WEAK NE FLOW OFF LAKE SUPERIOR. THIS SHOULD LEAD TO AT
LEAST SOME UPSLOPE SHOWERS/DRIZZLE CENTRAL AND EAST ALONG LAKE
SUPERIOR THROUGH MONDAY NIGHT. THEN...AN INVERSION AROUND 3KFT
COMBINED WITH THE WEAKENING IMPACT OF THE SUN FOR MIXING...MAY KEEP
THE AREA SOCKED IN WITH LOW CLOUDS THROUGHOUT THE DAY TUESDAY. HAVE
THUS CONTINUED THE TREND OF LOWERING HIGH TEMPS FOR TUESDAY...WITH
HIGHS GENERALLY IN THE 50S CWA-WIDE. ALSO...WITH LOW-LEVEL HIGH
PRESSURE SHIFTING EASTWARD NORTH OF LAKE SUPERIOR AND INITIATING
RETURN SOUTHERLY FLOW ACROSS THE AREA...IT MAY EVEN BE DIFFICULT TO
COMPLETELY RID THE AREA OF LOW CLOUDS BY TUESDAY NIGHT.
WEDNESDAY THROUGH FRIDAY...DEEP TROUGHING OVER THE NORTHERN ROCKIES
WILL BE LIFTING NORTHEASTWARD AS MID-LEVEL RIDGING OVER THE UPPER
GREAT LAKES SHIFTS EASTWARD. MODEL GUIDANCE IS IN FAIRLY GOOD
AGREEMENT WITH THE SYNOPTIC PATTERN...BUT DIFFERS SOMEWHAT WITH THE
OVERALL INTENSITY OF THE TROUGH AND ASSOCIATED SFC LOW. ATTM...A
COLD FRONT IS PROGGED TO SLOWLY TRACK EASTWARD ACROSS THE CWA
WEDNESDAY MORNING THROUGH THURSDAY NIGHT AS THE SFC LOW MOVES
NORTHWARD OVER MANITOBA. WILL MAINTAIN CONSENSUS POPS...WITH AN
EMPHASIS FOR BETTER CHANCES ON THURSDAY WITH THE ARRIVAL OF
UPPER-LEVEL SUPPORT FROM THE RIGHT ENTRANCE OF A JET.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 130 PM EDT FRI SEP 26 2014
WITH PLENTY OF DRY AIR ASSOCIATED WITH A HIGH PRESSURE RIDGE OVER
THE UPPER GREAT LAKES...EXPECT VFR CONDITIONS AND GENERALLY LIGHT
WINDS AT ALL SITES. KCMX SHOULD SEE AN EASTERLY LAKE BREEZE AFFECT THE
SITE IN THE AFTERNOON. FOG IS POSSIBLE AT ALL THREE SITES AGAIN
TONIGHT...WITH THE GREATEST CHANCE OF MVFR VSBY OR LOWER AT
KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 327 AM EDT FRI SEP 26 2014
A HIGH PRESSURE CENTERED OVER THE LOWER GREAT LAKES WILL REMAIN
STATIONARY THROUGH SUNDAY WHILE STRETCHING A RIDGE NORTHWEST ACROSS
THE UPPER GREAT LAKES. THIS WILL LEAD TO LIGHT SOUTHERLY FLOW
(BELOW 20KTS) INTO SUNDAY. A COLD FRONT DROPPING SOUTHEAST ACROSS
THE UPPER GREAT LAKES SUNDAY NIGHT INTO MONDAY MORNING WILL SHIFT
WINDS AROUND TO THE NORTHEAST WITH GUSTS TO 30KTS. THERE IS A
POTENTIAL FOR A FEW GALE FORCE GUSTS TO 35KTS LATE SUNDAY NIGHT
INTO MONDAY MORNING. HIGH PRESSURE CENTERED OVER EASTERN CANADA WILL
THEN PLACE A RIDGE OVER THE UPPER GREAT LAKES FOR MONDAY NIGHT AND
TUESDAY...LEADING TO DIMINISHING WINDS.
FINALLY...WITH MORE MOIST AIR BEGINNING TO WORK NORTH OVER LAKE
SUPERIOR...THERE IS THE POTENTIAL FOR PATCHY/AREAS OF FOG OVER
NORTHERN PORTIONS OF LAKE SUPERIOR OVER THE NEXT COUPLE OF DAYS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KLUBER
AVIATION...JLB
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
153 PM EDT FRI SEP 26 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM EDT FRI SEP 26 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS DATA SHOW AN UPPER RIDGE OVER
MUCH OF THE CENTRAL CONUS WHILE A DEEP UPPER TROUGH IS COMING ON
SHORE OVER THE WESTERN COAST OF THE CONUS. UNDER THE UPPER
RIDGE...THE REMNANTS OF THE UPPER LEVEL DISTURBANCE THAT AFFECTED
THE AREA 24 HOURS AGO IS SPINNING OVER THE MID MISSISSIPPI VALLEY.
AT THE SURFACE...A 1026MB HIGH IS STATIONARY OVER THE LOWER GREAT
LAKES AND STRETCHES A 1023MB RIDGE OVER THE UPPER GREAT LAKES
REGION. THIS RIDGE IS PROVIDING A SIGNIFICANT AMOUNT OF DRY AIR
BETWEEN 850-500MB AS SEEN ON THE 00Z KGRB/KAPX SOUNDINGS. THIS HAS
LED TO CLEAR SKIES OVER MUCH OF UPPER MICHIGAN EARLY THIS
MORNING...BUT SOME LINGERING LOW LEVEL MOISTURE REMAINS ON THE
NORTHWEST EDGE OF THE SURFACE RIDGE OVER NORTHERN LAKE SUEPRIOR AND
NORTHWEST ONTARIO. THESE CLOUDS HAVE BEEN GRADUALLY DISSIPATING
UNDER THE SUBSIDENCE ALOFT AND THE INFLUX OF DRIER AIR FROM THE
SOUTH-SOUTHWEST FLOW BETWEEN 925-850MB AND EXPECT THAT TO CONTINUE
THROUGH THE DAY TODAY. BACK TO UPPER MICHIGAN...THE CLEAR SKIES AND
LIGHT WINDS HAS LED TO PATCHY RADIATIONAL FOG TO DEVELOP OVER
PARTS OF THE CENTRAL/EASTERN U.P. AREAS NEAR LAKE MICHIGAN HAVE BEEN
SEEN FOG AS LOW AS 1/4MI THUS FAR AND EXPECT THAT AREA OF LOWER
VISIBILITIES TO EXPAND THROUGH SUNRISE. WILL MONITOR FOG TRENDS
AND IF THE LOWER VISIBILITIES BECOME MORE WIDESPREAD WILL ISSUE AN
SPS TO ADDRESS THE REDUCED VISIBILITIES INTO THE MORNING HOURS.
EXPECT THE FOG TO BURN OFF BETWEEN 14-15Z BASED OFF TIMING FROM A
COUPLE DAYS AGO AND GOES-R CLOUD THICKNESS DATA NEARING 900FT OVER
THE EAST LEADING TO A DISSIPATION TIME OF 2-2.5HRS AFTER SUNRISE.
AFTER THE FOG BURNS OFF...IT SHOULD BE A WONDERFULL EARLY FALL DAY
TO TAKE IN THE FALL COLORS. EXPECT SUNNY SKIES OVER MUCH OF THE
AREA...ALTHOUGH WITH THE NORTHWEST THIRD STILL NEAR SOME OF THE
DEPARTING 925-850MB MOISTURE WOULD EXPECT SOME DIURNAL CU TO
DEVELOP IN THAT AREA DURING PEAK HEATING. WITH PLENTY OF SUNSHINE
AND MIXING TO AROUND 875MB...EXPECT MOST AREAS TO BE IN THE MID 70S
FOR HIGHS TODAY. LIGHT SOUTHERLY FLOW WILL LEAD TO SLIGHTLY COOLER
VALUES NEAR LAKE MICHIGAN AND SLIGHTLY WARMER VALUES IN THE
DOWNSLOPE AREAS NEAR LAKE SUPERIOR.
WITH THE UPPER/SURFACE RIDGE NEARLY STATIONARY OVER THE AREA FOR
THE NEXT 24HRS...EXPECT FOG TO MAKE AN APPEARANCE ACROSS THE AREA
AGAIN TONIGHT. COVERAGE WILL LIKELY BE SIMILAR ACROSS THE
AREA...WITH THE LOWEST VISIBILITIES OVER THE CENTRAL/EAST AND
ESPECIALLY NEAR LAKE MICHIGAN.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 456 AM EDT FRI SEP 26 2014
AFTER A WARM AND MAINLY DRY WEEK...CHANGES ARE IN THE OFFING FOR
NEXT WEEK. STRONG RIDGE BUILDING INTO THE GREAT LAKES TODAY (500MB
HEIGHT ANOMALIES OF 2.5 STANDARD DEVIATIONS ARE NOTED ACROSS NRN
ONTARIO) AND THEN SHIFTING TO THE EAST COAST THIS WEEKEND WILL
MAINTAIN CURRENT WARM CONDITIONS FOR A FEW MORE DAYS. TROF
PROGRESSING ACROSS CANADA THIS WEEKEND WILL THEN SUPPRESS THE RIDGE
AND SEND A COLD FRONT THRU THE AREA EARLY NEXT WEEK...BRINGING SHARP
COOLING (ESPECIALLY NOTABLE NEAR LAKE SUPERIOR)...ALONG WITH THE
POTENTIAL FOR SHOWERS. THEREAFTER...A DEEPENING TROF INTO THE WRN
CONUS WILL FORCE A BUILDING RIDGE OVER THE ERN CONUS. THIS WILL
SUPPORT WARMING AGAIN OVER THE UPPER GREAT LAKES THRU THE MIDWEEK
PERIOD. AS THE TROF SHIFTS EASTWARD...THERE IS A GOOD SIGNAL FOR A
WET PERIOD AT SOME POINT DURING THE LAST HALF OF NEXT WEEK. A NUMBER
OF RECENT GFS RUNS AND SOME GEM ENSEMBLES HAVE POINTED TO THE
POTENTIAL FOR A DECENT FALL STORM TO EMERGE FROM THE TROF...SO THE
END OF NEXT WEEK MAY BE AN ACTIVE PERIOD. COLDER WEATHER WILL
CERTAINLY FOLLOW HEADING INTO THE FIRST WEEKEND OF OCT.
BEGINNING SAT...AFOREMENTIONED TROF SHIFTING ACROSS CANADA WILL PUSH
ASSOCIATED COLD FRONT INTO NRN ONTARIO. S/SW FLOW AHEAD OF FRONT
WILL MAINTAIN WARM CONDITIONS ACROSS THE FCST AREA. FCST SOUNDINGS
SHOW A MOSTLY DRY COLUMN...SO SKIES SHOULD BE MAINLY SUNNY AFTER
PATCHY SHALLOW FOG DISSIPATES. MIXING TO 850-825MB ON FCST SOUNDINGS
ALSO SUGGESTS MAX TEMPS WELL INTO THE 70S TO EVEN THE LWR 80S AWAY
FROM LAKE MODERATION WHICH SHOULD BE CONFINED MAINLY TO AREAS
DOWNWIND OF LAKE MICHIGAN. DRY CONDITIONS WILL CONTINUE INTO SAT
NIGHT. SHOULD SEE SOME FOG AGAIN...ESPECIALLY OVER THE SCNTRL AND ERN
FCST AREA.
ON SUN...COLD FRONT WILL CONTINUE TO SINK S AND E. MODELS INDICATE A
RIBBON OF LOW-MID LEVEL FRONTOGENESIS SETTING UP UNDER RIGHT
ENTRANCE OF UPPER JET STREAK SUPPORTING THE TROF HEADING INTO ERN
CANADA. THIS WILL IN TURN LEAD TO BAND OF RAIN DEVELOPING BEHIND THE
COLD FRONT. SO...TIMING OF FRONT WILL BE CRITICAL TO PCPN FCST AND
OBVIOUSLY TEMPS AS WELL. THE GFS/NAM SUGGEST FRONT WILL REACH LAKE
SUPERIOR AND ACCELERATE S...AT LEAST PASSING THRU THE KEWEENAW
PENINSULA DURING THE LATTER PORTION OF THE AFTN. GEM AND ECMWF ARE
JUST SLIGHTLY SLOWER. SO...THERE MAY BE SOME -RA BY EVENING OVER THE
KEWEENAW. OTHERWISE...NOT EXPECTING ANY PCPN AHEAD OF FRONT DESPITE
SOME INSTABILITY. NAM LOOKS MUCH OVERDONE WITH MLCAPE UPWARDS OF
1700J/KG. TEMPS SUN SHOULD BE SIMILAR TO SAT...EXCEPT A LITTLE
COOLER OVER THE KEWEENAW WITH ANTICIPATION OF WINDS VEERING MORE OFF
LAKE SUPERIOR AHEAD OF FRONT ARRIVING THERE IN THE LATER AFTN. IF
FRONT IS A LITTLE FASTER...THERE WILL BE SHARP COOLING ACROSS THE N
IN THE AFTN.
SUN NIGHT/MON...A TRAILING SHORTWAVE MOVING ACROSS SCNTRL CANADA IS
FCST TO DIG INTO THE UPPER GREAT LAKES...ENHANCING THE POST FRONTAL
PCPN AND HOLDING UP PROGRESSION OF COLD FRONT UNTIL THE WAVE PASSES.
INCLUDED CHC POPS ACROSS MAINLY THE N SUN NIGHT (LIKELY ACROSS THE
KEWEENAW OVERNIGHT) AS BEST FRONTOGENESIS FORCING IS STILL INDICATED
TO BE JUST N OF THE AREA. ON MON...BUMPED POPS UP TO LIKELY ACROSS
THE N AND E IN THE MORNING WHERE BEST FORCING IS EXPECTED.
OTHERWISE...MON WILL BE A SHARPLY COLDER DAY WITH RAIN AND BLUSTERY
N WINDS OFF CHILLY LAKE SUPERIOR. TEMPS WILL LIKELY ONLY BE IN THE
40S FOR MUCH OF THE DAY ACROSS MOST OF THE N. TEMPS COULD STILL
SURGE UP WELL INTO THE 60S ACROSS THE FAR SCNTRL IF THE COLD FRONT
DOESN`T ARRIVE UNTIL LATE MORNING OR AFTN.
PCPN WILL EXIT MON NIGHT...THOUGH SOME UPSLOPE -RA/-DZ MAY HOLD ON
ACROSS THE N GIVEN ABUNDANT LOW-LEVEL MOISTURE. POST FRONTAL LOW
CLOUDS MAY THEN PLAGUE THE AREA INTO AT LEAST PART OF TUE AS MODELS
INDICATE QUITE A BIT OF LOW-LEVEL MOISTURE LINGERING.
TROF DEVELOPING INTO THE WRN CONUS MID WEEK WILL SEND ONE PIECE OF
ENERGY N INTO THE NRN PLAINS TUE/EARLY WED BEFORE TROF BEGINS TO
SHIFT TOWARD THE CNTRL CONUS. LEAD WAVE MAY SPREAD SHRA INTO WRN
UPPER MI WED...BUT EXPECT BETTER POTENTIAL FOR PCPN TO ARRIVE THU AS
MAIN TROF MOVES OUT OVER THE PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 130 PM EDT FRI SEP 26 2014
WITH PLENTY OF DRY AIR ASSOCIATED WITH A HIGH PRESSURE RIDGE OVER
THE UPPER GREAT LAKES...EXPECT VFR CONDITIONS AND GENERALLY LIGHT
WINDS AT ALL SITES. KCMX SHOULD SEE AN EASTERLY LAKE BREEZE AFFECT THE
SITE IN THE AFTERNOON. FOG IS POSSIBLE AT ALL THREE SITES AGAIN
TONIGHT...WITH THE GREATEST CHANCE OF MVFR VSBY OR LOWER AT
KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 327 AM EDT FRI SEP 26 2014
A HIGH PRESSURE CENTERED OVER THE LOWER GREAT LAKES WILL REMAIN
STATIONARY THROUGH SUNDAY WHILE STRETCHING A RIDGE NORTHWEST ACROSS
THE UPPER GREAT LAKES. THIS WILL LEAD TO LIGHT SOUTHERLY FLOW
(BELOW 20KTS) INTO SUNDAY. A COLD FRONT DROPPING SOUTHEAST ACROSS
THE UPPER GREAT LAKES SUNDAY NIGHT INTO MONDAY MORNING WILL SHIFT
WINDS AROUND TO THE NORTHEAST WITH GUSTS TO 30KTS. THERE IS A
POTENTIAL FOR A FEW GALE FORCE GUSTS TO 35KTS LATE SUNDAY NIGHT
INTO MONDAY MORNING. HIGH PRESSURE CENTERED OVER EASTERN CANADA WILL
THEN PLACE A RIDGE OVER THE UPPER GREAT LAKES FOR MONDAY NIGHT AND
TUESDAY...LEADING TO DIMINISHING WINDS.
FINALLY...WITH MORE MOIST AIR BEGINNING TO WORK NORTH OVER LAKE
SUPERIOR...THERE IS THE POTENTIAL FOR PATCHY/AREAS OF FOG OVER
NORTHERN PORTIONS OF LAKE SUPERIOR OVER THE NEXT COUPLE OF DAYS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...JLB
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
731 AM EDT FRI SEP 26 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM EDT FRI SEP 26 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS DATA SHOW AN UPPER RIDGE OVER
MUCH OF THE CENTRAL CONUS WHILE A DEEP UPPER TROUGH IS COMING ON
SHORE OVER THE WESTERN COAST OF THE CONUS. UNDER THE UPPER
RIDGE...THE REMNANTS OF THE UPPER LEVEL DISTURBANCE THAT AFFECTED
THE AREA 24 HOURS AGO IS SPINNING OVER THE MID MISSISSIPPI VALLEY.
AT THE SURFACE...A 1026MB HIGH IS STATIONARY OVER THE LOWER GREAT
LAKES AND STRETCHES A 1023MB RIDGE OVER THE UPPER GREAT LAKES
REGION. THIS RIDGE IS PROVIDING A SIGNIFICANT AMOUNT OF DRY AIR
BETWEEN 850-500MB AS SEEN ON THE 00Z KGRB/KAPX SOUNDINGS. THIS HAS
LED TO CLEAR SKIES OVER MUCH OF UPPER MICHIGAN EARLY THIS
MORNING...BUT SOME LINGERING LOW LEVEL MOISTURE REMAINS ON THE
NORTHWEST EDGE OF THE SURFACE RIDGE OVER NORTHERN LAKE SUEPRIOR AND
NORTHWEST ONTARIO. THESE CLOUDS HAVE BEEN GRADUALLY DISSIPATING
UNDER THE SUBSIDENCE ALOFT AND THE INFLUX OF DRIER AIR FROM THE
SOUTH-SOUTHWEST FLOW BETWEEN 925-850MB AND EXPECT THAT TO CONTINUE
THROUGH THE DAY TODAY. BACK TO UPPER MICHIGAN...THE CLEAR SKIES AND
LIGHT WINDS HAS LED TO PATCHY RADIATIONAL FOG TO DEVELOP OVER
PARTS OF THE CENTRAL/EASTERN U.P. AREAS NEAR LAKE MICHIGAN HAVE BEEN
SEEN FOG AS LOW AS 1/4MI THUS FAR AND EXPECT THAT AREA OF LOWER
VISIBILITIES TO EXPAND THROUGH SUNRISE. WILL MONITOR FOG TRENDS
AND IF THE LOWER VISIBILITIES BECOME MORE WIDESPREAD WILL ISSUE AN
SPS TO ADDRESS THE REDUCED VISIBILITIES INTO THE MORNING HOURS.
EXPECT THE FOG TO BURN OFF BETWEEN 14-15Z BASED OFF TIMING FROM A
COUPLE DAYS AGO AND GOES-R CLOUD THICKNESS DATA NEARING 900FT OVER
THE EAST LEADING TO A DISSIPATION TIME OF 2-2.5HRS AFTER SUNRISE.
AFTER THE FOG BURNS OFF...IT SHOULD BE A WONDERFULL EARLY FALL DAY
TO TAKE IN THE FALL COLORS. EXPECT SUNNY SKIES OVER MUCH OF THE
AREA...ALTHOUGH WITH THE NORTHWEST THIRD STILL NEAR SOME OF THE
DEPARTING 925-850MB MOISTURE WOULD EXPECT SOME DIURNAL CU TO
DEVELOP IN THAT AREA DURING PEAK HEATING. WITH PLENTY OF SUNSHINE
AND MIXING TO AROUND 875MB...EXPECT MOST AREAS TO BE IN THE MID 70S
FOR HIGHS TODAY. LIGHT SOUTHERLY FLOW WILL LEAD TO SLIGHTLY COOLER
VALUES NEAR LAKE MICHIGAN AND SLIGHTLY WARMER VALUES IN THE
DOWNSLOPE AREAS NEAR LAKE SUPERIOR.
WITH THE UPPER/SURFACE RIDGE NEARLY STATIONARY OVER THE AREA FOR
THE NEXT 24HRS...EXPECT FOG TO MAKE AN APPEARANCE ACROSS THE AREA
AGAIN TONIGHT. COVERAGE WILL LIKELY BE SIMILAR ACROSS THE
AREA...WITH THE LOWEST VISIBILITIES OVER THE CENTRAL/EAST AND
ESPECIALLY NEAR LAKE MICHIGAN.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 456 AM EDT FRI SEP 26 2014
AFTER A WARM AND MAINLY DRY WEEK...CHANGES ARE IN THE OFFING FOR
NEXT WEEK. STRONG RIDGE BUILDING INTO THE GREAT LAKES TODAY (500MB
HEIGHT ANOMALIES OF 2.5 STANDARD DEVIATIONS ARE NOTED ACROSS NRN
ONTARIO) AND THEN SHIFTING TO THE EAST COAST THIS WEEKEND WILL
MAINTAIN CURRENT WARM CONDITIONS FOR A FEW MORE DAYS. TROF
PROGRESSING ACROSS CANADA THIS WEEKEND WILL THEN SUPPRESS THE RIDGE
AND SEND A COLD FRONT THRU THE AREA EARLY NEXT WEEK...BRINGING SHARP
COOLING (ESPECIALLY NOTABLE NEAR LAKE SUPERIOR)...ALONG WITH THE
POTENTIAL FOR SHOWERS. THEREAFTER...A DEEPENING TROF INTO THE WRN
CONUS WILL FORCE A BUILDING RIDGE OVER THE ERN CONUS. THIS WILL
SUPPORT WARMING AGAIN OVER THE UPPER GREAT LAKES THRU THE MIDWEEK
PERIOD. AS THE TROF SHIFTS EASTWARD...THERE IS A GOOD SIGNAL FOR A
WET PERIOD AT SOME POINT DURING THE LAST HALF OF NEXT WEEK. A NUMBER
OF RECENT GFS RUNS AND SOME GEM ENSEMBLES HAVE POINTED TO THE
POTENTIAL FOR A DECENT FALL STORM TO EMERGE FROM THE TROF...SO THE
END OF NEXT WEEK MAY BE AN ACTIVE PERIOD. COLDER WEATHER WILL
CERTAINLY FOLLOW HEADING INTO THE FIRST WEEKEND OF OCT.
BEGINNING SAT...AFOREMENTIONED TROF SHIFTING ACROSS CANADA WILL PUSH
ASSOCIATED COLD FRONT INTO NRN ONTARIO. S/SW FLOW AHEAD OF FRONT
WILL MAINTAIN WARM CONDITIONS ACROSS THE FCST AREA. FCST SOUNDINGS
SHOW A MOSTLY DRY COLUMN...SO SKIES SHOULD BE MAINLY SUNNY AFTER
PATCHY SHALLOW FOG DISSIPATES. MIXING TO 850-825MB ON FCST SOUNDINGS
ALSO SUGGESTS MAX TEMPS WELL INTO THE 70S TO EVEN THE LWR 80S AWAY
FROM LAKE MODERATION WHICH SHOULD BE CONFINED MAINLY TO AREAS
DOWNWIND OF LAKE MICHIGAN. DRY CONDITIONS WILL CONTINUE INTO SAT
NIGHT. SHOULD SEE SOME FOG AGAIN...ESPECIALLY OVER THE SCNTRL AND ERN
FCST AREA.
ON SUN...COLD FRONT WILL CONTINUE TO SINK S AND E. MODELS INDICATE A
RIBBON OF LOW-MID LEVEL FRONTOGENESIS SETTING UP UNDER RIGHT
ENTRANCE OF UPPER JET STREAK SUPPORTING THE TROF HEADING INTO ERN
CANADA. THIS WILL IN TURN LEAD TO BAND OF RAIN DEVELOPING BEHIND THE
COLD FRONT. SO...TIMING OF FRONT WILL BE CRITICAL TO PCPN FCST AND
OBVIOUSLY TEMPS AS WELL. THE GFS/NAM SUGGEST FRONT WILL REACH LAKE
SUPERIOR AND ACCELERATE S...AT LEAST PASSING THRU THE KEWEENAW
PENINSULA DURING THE LATTER PORTION OF THE AFTN. GEM AND ECMWF ARE
JUST SLIGHTLY SLOWER. SO...THERE MAY BE SOME -RA BY EVENING OVER THE
KEWEENAW. OTHERWISE...NOT EXPECTING ANY PCPN AHEAD OF FRONT DESPITE
SOME INSTABILITY. NAM LOOKS MUCH OVERDONE WITH MLCAPE UPWARDS OF
1700J/KG. TEMPS SUN SHOULD BE SIMILAR TO SAT...EXCEPT A LITTLE
COOLER OVER THE KEWEENAW WITH ANTICIPATION OF WINDS VEERING MORE OFF
LAKE SUPERIOR AHEAD OF FRONT ARRIVING THERE IN THE LATER AFTN. IF
FRONT IS A LITTLE FASTER...THERE WILL BE SHARP COOLING ACROSS THE N
IN THE AFTN.
SUN NIGHT/MON...A TRAILING SHORTWAVE MOVING ACROSS SCNTRL CANADA IS
FCST TO DIG INTO THE UPPER GREAT LAKES...ENHANCING THE POST FRONTAL
PCPN AND HOLDING UP PROGRESSION OF COLD FRONT UNTIL THE WAVE PASSES.
INCLUDED CHC POPS ACROSS MAINLY THE N SUN NIGHT (LIKELY ACROSS THE
KEWEENAW OVERNIGHT) AS BEST FRONTOGENESIS FORCING IS STILL INDICATED
TO BE JUST N OF THE AREA. ON MON...BUMPED POPS UP TO LIKELY ACROSS
THE N AND E IN THE MORNING WHERE BEST FORCING IS EXPECTED.
OTHERWISE...MON WILL BE A SHARPLY COLDER DAY WITH RAIN AND BLUSTERY
N WINDS OFF CHILLY LAKE SUPERIOR. TEMPS WILL LIKELY ONLY BE IN THE
40S FOR MUCH OF THE DAY ACROSS MOST OF THE N. TEMPS COULD STILL
SURGE UP WELL INTO THE 60S ACROSS THE FAR SCNTRL IF THE COLD FRONT
DOESN`T ARRIVE UNTIL LATE MORNING OR AFTN.
PCPN WILL EXIT MON NIGHT...THOUGH SOME UPSLOPE -RA/-DZ MAY HOLD ON
ACROSS THE N GIVEN ABUNDANT LOW-LEVEL MOISTURE. POST FRONTAL LOW
CLOUDS MAY THEN PLAGUE THE AREA INTO AT LEAST PART OF TUE AS MODELS
INDICATE QUITE A BIT OF LOW-LEVEL MOISTURE LINGERING.
TROF DEVELOPING INTO THE WRN CONUS MID WEEK WILL SEND ONE PIECE OF
ENERGY N INTO THE NRN PLAINS TUE/EARLY WED BEFORE TROF BEGINS TO
SHIFT TOWARD THE CNTRL CONUS. LEAD WAVE MAY SPREAD SHRA INTO WRN
UPPER MI WED...BUT EXPECT BETTER POTENTIAL FOR PCPN TO ARRIVE THU AS
MAIN TROF MOVES OUT OVER THE PLAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 729 AM EDT FRI SEP 26 2014
FOG HAS BEEN STAYING JUST TO THE SOUTH OF THE TAF SITES THIS
MORNING AND WITH SUNRISE OCCURRING SHORTLY...EXPECT THE POTENTIAL
FOR FOG TO DIMINISH QUICKLY THIS MORNING. WITH PLENTY OF DRY AIR
ASSOCIATED WITH A HIGH PRESSURE RIDGE OVER THE UPPER GREAT
LAKES...EXPECT VFR CONDITIONS AND GENERALLY LIGHT WINDS AT ALL
SITES. THERE MAY BE A FEW DIURNAL CLOUDS AT KIWD/KCMX THIS
AFTERNOON. IN ADDITION...KCMX WILL SEE AN EASTERLY LAKE BREEZE
AFFECT THE SITE IN THE AFTERNOON. FOG IS POSSIBLE AT ALL THREE
SITES AGAIN TONIGHT...WITH THE WORST CONDITIONS EXPECTED TO OCCUR AT
KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 327 AM EDT FRI SEP 26 2014
A HIGH PRESSURE CENTERED OVER THE LOWER GREAT LAKES WILL REMAIN
STATIONARY THROUGH SUNDAY WHILE STRETCHING A RIDGE NORTHWEST ACROSS
THE UPPER GREAT LAKES. THIS WILL LEAD TO LIGHT SOUTHERLY FLOW
(BELOW 20KTS) INTO SUNDAY. A COLD FRONT DROPPING SOUTHEAST ACROSS
THE UPPER GREAT LAKES SUNDAY NIGHT INTO MONDAY MORNING WILL SHIFT
WINDS AROUND TO THE NORTHEAST WITH GUSTS TO 30KTS. THERE IS A
POTENTIAL FOR A FEW GALE FORCE GUSTS TO 35KTS LATE SUNDAY NIGHT
INTO MONDAY MORNING. HIGH PRESSURE CENTERED OVER EASTERN CANADA WILL
THEN PLACE A RIDGE OVER THE UPPER GREAT LAKES FOR MONDAY NIGHT AND
TUESDAY...LEADING TO DIMINISHING WINDS.
FINALLY...WITH MORE MOIST AIR BEGINNING TO WORK NORTH OVER LAKE
SUPERIOR...THERE IS THE POTENTIAL FOR PATCHY/AREAS OF FOG OVER
NORTHERN PORTIONS OF LAKE SUPERIOR OVER THE NEXT COUPLE OF DAYS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
457 AM EDT FRI SEP 26 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM EDT FRI SEP 26 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS DATA SHOW AN UPPER RIDGE OVER
MUCH OF THE CENTRAL CONUS WHILE A DEEP UPPER TROUGH IS COMING ON
SHORE OVER THE WESTERN COAST OF THE CONUS. UNDER THE UPPER
RIDGE...THE REMNANTS OF THE UPPER LEVEL DISTURBANCE THAT AFFECTED
THE AREA 24 HOURS AGO IS SPINNING OVER THE MID MISSISSIPPI VALLEY.
AT THE SURFACE...A 1026MB HIGH IS STATIONARY OVER THE LOWER GREAT
LAKES AND STRETCHES A 1023MB RIDGE OVER THE UPPER GREAT LAKES
REGION. THIS RIDGE IS PROVIDING A SIGNIFICANT AMOUNT OF DRY AIR
BETWEEN 850-500MB AS SEEN ON THE 00Z KGRB/KAPX SOUNDINGS. THIS HAS
LED TO CLEAR SKIES OVER MUCH OF UPPER MICHIGAN EARLY THIS
MORNING...BUT SOME LINGERING LOW LEVEL MOISTURE REMAINS ON THE
NORTHWEST EDGE OF THE SURFACE RIDGE OVER NORTHERN LAKE SUEPRIOR AND
NORTHWEST ONTARIO. THESE CLOUDS HAVE BEEN GRADUALLY DISSIPATING
UNDER THE SUBSIDENCE ALOFT AND THE INFLUX OF DRIER AIR FROM THE
SOUTH-SOUTHWEST FLOW BETWEEN 925-850MB AND EXPECT THAT TO CONTINUE
THROUGH THE DAY TODAY. BACK TO UPPER MICHIGAN...THE CLEAR SKIES AND
LIGHT WINDS HAS LED TO PATCHY RADIATIONAL FOG TO DEVELOP OVER
PARTS OF THE CENTRAL/EASTERN U.P. AREAS NEAR LAKE MICHIGAN HAVE BEEN
SEEN FOG AS LOW AS 1/4MI THUS FAR AND EXPECT THAT AREA OF LOWER
VISIBILITIES TO EXPAND THROUGH SUNRISE. WILL MONITOR FOG TRENDS
AND IF THE LOWER VISIBILITIES BECOME MORE WIDESPREAD WILL ISSUE AN
SPS TO ADDRESS THE REDUCED VISIBILITIES INTO THE MORNING HOURS.
EXPECT THE FOG TO BURN OFF BETWEEN 14-15Z BASED OFF TIMING FROM A
COUPLE DAYS AGO AND GOES-R CLOUD THICKNESS DATA NEARING 900FT OVER
THE EAST LEADING TO A DISSIPATION TIME OF 2-2.5HRS AFTER SUNRISE.
AFTER THE FOG BURNS OFF...IT SHOULD BE A WONDERFULL EARLY FALL DAY
TO TAKE IN THE FALL COLORS. EXPECT SUNNY SKIES OVER MUCH OF THE
AREA...ALTHOUGH WITH THE NORTHWEST THIRD STILL NEAR SOME OF THE
DEPARTING 925-850MB MOISTURE WOULD EXPECT SOME DIURNAL CU TO
DEVELOP IN THAT AREA DURING PEAK HEATING. WITH PLENTY OF SUNSHINE
AND MIXING TO AROUND 875MB...EXPECT MOST AREAS TO BE IN THE MID 70S
FOR HIGHS TODAY. LIGHT SOUTHERLY FLOW WILL LEAD TO SLIGHTLY COOLER
VALUES NEAR LAKE MICHIGAN AND SLIGHTLY WARMER VALUES IN THE
DOWNSLOPE AREAS NEAR LAKE SUPERIOR.
WITH THE UPPER/SURFACE RIDGE NEARLY STATIONARY OVER THE AREA FOR
THE NEXT 24HRS...EXPECT FOG TO MAKE AN APPEARANCE ACROSS THE AREA
AGAIN TONIGHT. COVERAGE WILL LIKELY BE SIMILAR ACROSS THE
AREA...WITH THE LOWEST VISIBILITIES OVER THE CENTRAL/EAST AND
ESPECIALLY NEAR LAKE MICHIGAN.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 456 AM EDT FRI SEP 26 2014
AFTER A WARM AND MAINLY DRY WEEK...CHANGES ARE IN THE OFFING FOR
NEXT WEEK. STRONG RIDGE BUILDING INTO THE GREAT LAKES TODAY (500MB
HEIGHT ANOMALIES OF 2.5 STANDARD DEVIATIONS ARE NOTED ACROSS NRN
ONTARIO) AND THEN SHIFTING TO THE EAST COAST THIS WEEKEND WILL
MAINTAIN CURRENT WARM CONDITIONS FOR A FEW MORE DAYS. TROF
PROGRESSING ACROSS CANADA THIS WEEKEND WILL THEN SUPPRESS THE RIDGE
AND SEND A COLD FRONT THRU THE AREA EARLY NEXT WEEK...BRINGING SHARP
COOLING (ESPECIALLY NOTABLE NEAR LAKE SUPERIOR)...ALONG WITH THE
POTENTIAL FOR SHOWERS. THEREAFTER...A DEEPENING TROF INTO THE WRN
CONUS WILL FORCE A BUILDING RIDGE OVER THE ERN CONUS. THIS WILL
SUPPORT WARMING AGAIN OVER THE UPPER GREAT LAKES THRU THE MIDWEEK
PERIOD. AS THE TROF SHIFTS EASTWARD...THERE IS A GOOD SIGNAL FOR A
WET PERIOD AT SOME POINT DURING THE LAST HALF OF NEXT WEEK. A NUMBER
OF RECENT GFS RUNS AND SOME GEM ENSEMBLES HAVE POINTED TO THE
POTENTIAL FOR A DECENT FALL STORM TO EMERGE FROM THE TROF...SO THE
END OF NEXT WEEK MAY BE AN ACTIVE PERIOD. COLDER WEATHER WILL
CERTAINLY FOLLOW HEADING INTO THE FIRST WEEKEND OF OCT.
BEGINNING SAT...AFOREMENTIONED TROF SHIFTING ACROSS CANADA WILL PUSH
ASSOCIATED COLD FRONT INTO NRN ONTARIO. S/SW FLOW AHEAD OF FRONT
WILL MAINTAIN WARM CONDITIONS ACROSS THE FCST AREA. FCST SOUNDINGS
SHOW A MOSTLY DRY COLUMN...SO SKIES SHOULD BE MAINLY SUNNY AFTER
PATCHY SHALLOW FOG DISSIPATES. MIXING TO 850-825MB ON FCST SOUNDINGS
ALSO SUGGESTS MAX TEMPS WELL INTO THE 70S TO EVEN THE LWR 80S AWAY
FROM LAKE MODERATION WHICH SHOULD BE CONFINED MAINLY TO AREAS
DOWNWIND OF LAKE MICHIGAN. DRY CONDITIONS WILL CONTINUE INTO SAT
NIGHT. SHOULD SEE SOME FOG AGAIN...ESPECIALLY OVER THE SCNTRL AND ERN
FCST AREA.
ON SUN...COLD FRONT WILL CONTINUE TO SINK S AND E. MODELS INDICATE A
RIBBON OF LOW-MID LEVEL FRONTOGENESIS SETTING UP UNDER RIGHT
ENTRANCE OF UPPER JET STREAK SUPPORTING THE TROF HEADING INTO ERN
CANADA. THIS WILL IN TURN LEAD TO BAND OF RAIN DEVELOPING BEHIND THE
COLD FRONT. SO...TIMING OF FRONT WILL BE CRITICAL TO PCPN FCST AND
OBVIOUSLY TEMPS AS WELL. THE GFS/NAM SUGGEST FRONT WILL REACH LAKE
SUPERIOR AND ACCELERATE S...AT LEAST PASSING THRU THE KEWEENAW
PENINSULA DURING THE LATTER PORTION OF THE AFTN. GEM AND ECMWF ARE
JUST SLIGHTLY SLOWER. SO...THERE MAY BE SOME -RA BY EVENING OVER THE
KEWEENAW. OTHERWISE...NOT EXPECTING ANY PCPN AHEAD OF FRONT DESPITE
SOME INSTABILITY. NAM LOOKS MUCH OVERDONE WITH MLCAPE UPWARDS OF
1700J/KG. TEMPS SUN SHOULD BE SIMILAR TO SAT...EXCEPT A LITTLE
COOLER OVER THE KEWEENAW WITH ANTICIPATION OF WINDS VEERING MORE OFF
LAKE SUPERIOR AHEAD OF FRONT ARRIVING THERE IN THE LATER AFTN. IF
FRONT IS A LITTLE FASTER...THERE WILL BE SHARP COOLING ACROSS THE N
IN THE AFTN.
SUN NIGHT/MON...A TRAILING SHORTWAVE MOVING ACROSS SCNTRL CANADA IS
FCST TO DIG INTO THE UPPER GREAT LAKES...ENHANCING THE POST FRONTAL
PCPN AND HOLDING UP PROGRESSION OF COLD FRONT UNTIL THE WAVE PASSES.
INCLUDED CHC POPS ACROSS MAINLY THE N SUN NIGHT (LIKELY ACROSS THE
KEWEENAW OVERNIGHT) AS BEST FRONTOGENESIS FORCING IS STILL INDICATED
TO BE JUST N OF THE AREA. ON MON...BUMPED POPS UP TO LIKELY ACROSS
THE N AND E IN THE MORNING WHERE BEST FORCING IS EXPECTED.
OTHERWISE...MON WILL BE A SHARPLY COLDER DAY WITH RAIN AND BLUSTERY
N WINDS OFF CHILLY LAKE SUPERIOR. TEMPS WILL LIKELY ONLY BE IN THE
40S FOR MUCH OF THE DAY ACROSS MOST OF THE N. TEMPS COULD STILL
SURGE UP WELL INTO THE 60S ACROSS THE FAR SCNTRL IF THE COLD FRONT
DOESN`T ARRIVE UNTIL LATE MORNING OR AFTN.
PCPN WILL EXIT MON NIGHT...THOUGH SOME UPSLOPE -RA/-DZ MAY HOLD ON
ACROSS THE N GIVEN ABUNDANT LOW-LEVEL MOISTURE. POST FRONTAL LOW
CLOUDS MAY THEN PLAGUE THE AREA INTO AT LEAST PART OF TUE AS MODELS
INDICATE QUITE A BIT OF LOW-LEVEL MOISTURE LINGERING.
TROF DEVELOPING INTO THE WRN CONUS MID WEEK WILL SEND ONE PIECE OF
ENERGY N INTO THE NRN PLAINS TUE/EARLY WED BEFORE TROF BEGINS TO
SHIFT TOWARD THE CNTRL CONUS. LEAD WAVE MAY SPREAD SHRA INTO WRN
UPPER MI WED...BUT EXPECT BETTER POTENTIAL FOR PCPN TO ARRIVE THU AS
MAIN TROF MOVES OUT OVER THE PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 122 AM EDT FRI SEP 26 2014
UNDER MOCLR SKIES WITH LGT WINDS...EXPECT SOME FOG TO DVLP AT SAW
AND BRING A PERIOD OF IFR VSBYS TOWARD SUNRISE. SINCE THE LO CLDS
HAVE BECOME SCT OVER WRN UPR MI...SOME FOG MAY FORM AT IWD AND CMX
AS WELL. OPTED TO INCLUDE A VSBY RESTRICTION AT CMX ONLY AS STEADY
SSW WIND AT IWD SHOULD RESULT IN ENUF DOWNSLOPE WARMING TO LIMIT THE
POTENTIAL FOR FOG THERE. AFTER ANY MRNG FOG BURNS OFF...EXPECT VFR
CONDITIONS THRU FRI EVNG AT ALL 3 SITES WITH DRY ACYC SW FLOW ARND
HI PRES OVER LOWER MI.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 327 AM EDT FRI SEP 26 2014
A HIGH PRESSURE CENTERED OVER THE LOWER GREAT LAKES WILL REMAIN
STATIONARY THROUGH SUNDAY WHILE STRETCHING A RIDGE NORTHWEST ACROSS
THE UPPER GREAT LAKES. THIS WILL LEAD TO LIGHT SOUTHERLY FLOW
(BELOW 20KTS) INTO SUNDAY. A COLD FRONT DROPPING SOUTHEAST ACROSS
THE UPPER GREAT LAKES SUNDAY NIGHT INTO MONDAY MORNING WILL SHIFT
WINDS AROUND TO THE NORTHEAST WITH GUSTS TO 30KTS. THERE IS A
POTENTIAL FOR A FEW GALE FORCE GUSTS TO 35KTS LATE SUNDAY NIGHT
INTO MONDAY MORNING. HIGH PRESSURE CENTERED OVER EASTERN CANADA WILL
THEN PLACE A RIDGE OVER THE UPPER GREAT LAKES FOR MONDAY NIGHT AND
TUESDAY...LEADING TO DIMINISHING WINDS.
FINALLY...WITH MORE MOIST AIR BEGINNING TO WORK NORTH OVER LAKE
SUPERIOR...THERE IS THE POTENTIAL FOR PATCHY/AREAS OF FOG OVER
NORTHERN PORTIONS OF LAKE SUPERIOR OVER THE NEXT COUPLE OF DAYS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1230 AM CDT FRI SEP 26 2014
.UPDATE...
ISSUED AT 632 PM CDT THU SEP 25 2014
UPDATED AVIATION DISCUSSION FOR 06Z TAF ISSUANCE BELOW.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 259 PM CDT THU SEP 25 2014
TONIGHT...NOT AN EASY FORECAST DUE TO UNCERTAINTY OF LOW CLOUD/FOG
DEVELOPMENT SCENARIO. EXPECT CLEARING TREND TO CONTINUE INTO EARLY
EVENING BEFORE AREAS OF BR/FOG OCCUR. HAVE PLACED BEST GUESS OF
AREAL COVERAGE OF FOG BASED ON FCST OF COND PRESS DEFICITS FROM
HI-RES MDLS...FCST HYDROLAPSES FROM NAM BUFR...AND LATEST HRRR FCST
OF VIS THIS WOULD FAVOR THE CORRIDOR FROM THE NORTH SHORE TO THE
TWIN PORTS AND EXTENDING TO THE BRD LAKES REGION AS MOST LIKELY
TO HAVE ISSUES. EVENING SHIFT MAY NEED TO ENHANCE FOG DEVELOPMENT
ESPECIALLY IF EXTENSIVE CLEARING OCCURS. A CONUNDRUM EXISTS AS TO
WHETHER LOW STRATUS REDEVELOPMENT IS MORE WIDESPREAD THAN CURRENTLY
FCST.
TOMORROW...ANOMALOUS MID LVL RIDGE WILL OCCUPY THE REGION WITH
FORMER MID LVL LOW SHUFFLING SOUTHWEST TOWARDS SRN IA. EARLY MORNING
BR/FG...AND POSSIBLY LOW STRATUS...SHOULD ERODE AS BDRY LYR WARMING
COMMENCES BY 15Z. FCST SNDGS SUGGEST THAT ONCE MIXING LAYER IS
ESTABLISHED THERE SHOULD BE A TREND TOWARDS SOME INCREASE IN
PREVAILING SOUTHERLY WIND...AND OCCASIONAL GUSTS. TEMPS WILL RESPOND
TO DEEPENING MIXED LAYER AMIDST ANOMALOUS LOW LVL THICKNESSES AND
WARM INTO THE MID TO UPPER 70S IN MOST LOCATIONS...EXCEPT THE MARINE
INFLUENCED COASTAL REGIONS OF LAKE/COOK COUNTIES.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 259 PM CDT THU SEP 25 2014
A BROAD AREA OF RIDGING WILL BRING CONTINUED QUIET WEATHER AND ABOVE
NORMAL TEMPERATURES THROUGH THE WEEKEND. WARM TEMPS AND GOOD
AFTERNOON MIXING TO 5 KFT SATURDAY AND SUNDAY WILL ALLOW FOR GUSTY
SOUTH WINDS GENERALLY AROUND 20 MPH.
HAVE INCREASED POPS SUNDAY NIGHT THROUGH MONDAY AS LATEST ECM/GFS
ARE IN AGREEMENT THAT A VORT MAX TRANSLATES EAST ALONG A STALLED
BAROCLINIC ZONE POSITIONED JUST NORTH OF THE INTERNATIONAL BORDER.
THE SHORT WAVE WILL PUSH THE FRONT SOUTH OVER THE NORTHERN ZONES AND
OVER LAKE SUPERIOR DURING THE SUNDAY NIGHT/MONDAY TIME FRAME. AS
THE SHORT WAVES DEPARTS MONDAY EVENING...THE FRONT WILL AGAIN PUSH
NORTH INTO CANADA AS SOUTHERLY WINDS/WARM AIR ADVECTION INCREASE
OVER THE REGION.
THERE REMAINS SOME UNCERTAINTY HOW FAR SOUTH INTO NE THE FRONT AND
ASSOCIATED RAIN WILL PUSH SUNDAY NIGHT/MONDAY. AT THIS TIME...THE
BEST CHANCE FOR RAINFALL AMOUNTS ON THE ORDER OF A HALF INCH WILL BE
ALONG AND NORTH OF A LINE FROM WALKER...TO GRAND
RAPIDS...VIRGINIA....AND SILVER BAY.
A LONG WAVE TROUGH WILL MAKE LANDFALL IN THE PACIFIC NORTHWEST
THROUGH THE WEEKEND...SHIFTING EAST OVER THE ROCKIES/UPPER MIDWEST
THROUGH THE MIDDLE OF NEXT WEEK. THIS FEATURE WILL BRING EMBEDDED
SHORT WAVES...AND INCREASING SHOWERS AND POSSIBLE TSTM CHANCES FOR
THE LATER HALF OF THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1229 AMCDT FRI SEP 26 2014
RESIDUAL LOW LEVEL MOISTURE REMAINS TRAPPED UNDERNEATH INVERSION
AROUND 900 MB ACROSS MUCH OF NE MN LATE THIS EVENING..AND STRATUS
CLOUDS WILL CONTINUE TO BE SLOW TO CLEAR OVERNIGHT. AREAS THAT DO
SEE CLEARING WILL LIKELY SEE RATHER RAPID REFORMATION OF FOG AS HAS
ALREADY BEEN SEEN AT KHIB. THIS IS LIKELY TO AFFECT ALL TAF SITES
THRU 12-14Z..WITH POTENTIAL FOR MOST SIG VISIBILITY RESTRICTIONS AT
KDLH/KHIB/KHYR.
INCREASING SOUTHERLY SFC FLOW SHOULD ALLOW A MUCH MORE EFFECTIVE
MIXING OUT OF LOW LEVEL MOISTURE ON FRIDAY WITH CLOUDS/FOG RAPIDLY
DISSIPATING 13-15Z..WITH FORMATION OF SCT CUMULUS THEREAFTER WITH
DAYTIME DEEPENING OF THE BOUNDARY LAYER. WINDS ARE LIKELY TO BE A
BIT GUSTY FRIDAY AS WELL WITH A SLOWLY TIGHTENING SOUTHERLY GRADIENT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 56 76 56 74 / 0 10 10 10
INL 56 78 56 73 / 0 10 20 20
BRD 58 78 56 75 / 0 10 0 10
HYR 54 76 55 76 / 0 10 10 10
ASX 56 75 56 74 / 0 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...CANNON
LONG TERM...GRANING
AVIATION...CLC/DJM
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
836 PM CDT SAT SEP 27 2014
.UPDATE...
INCREASING MOISTURE TRANSPORT TONIGHT FROM WEAK LOW PRESSURE WILL
LEAD TO POTENTIAL FOR SHOWERS/STORMS IN SE MS. HAD TO CUT DOWN
POPS...ESPECIALLY IN CENTRAL/E MS...AS MOST OF THE RAIN IS CONFINED
ALONG THE STALLED FRONTAL BOUNDARY OVER THE GULF OF MEXICO. LOCAL WRF
SEEMED TO NOT HAVE A HANDLE ON THE PRECIP AXIS AS WELL AS THE
HRRR...WHICH KEPT MOST OF THE ACTIVITY CONFINED TO THE COAST/SE MS
TONIGHT. THUS...REMOVED POPS BEFORE 12Z TONIGHT FOR CENTRAL MS WHILE
DECREASING IN E/SE MS. DECIDED TO KEEP SOME CHANCE POPS IN BEFORE 12Z
SUNDAY IN E/SE MS...EVEN WITH THE HRRR REALLY BACKING OFF ON ACTIVITY
MAKING MUCH OF A NRN PUSH. GFS BRINGS SOME IN SE MS WHILE EURO IS MORE
AGGRESSIVE WITH MOISTURE TRANSPORT MOVING INTO SE MS. TRIED TO GO
WITH A BLEND FOR POPS AND BRING SOME IN SE MS AFTER MIDNIGHT...FARTHER
NW THAN THE GFS BUT NOT AS FAR N AND W AS THE EURO. THERE WILL BE
SOME CHANCES FOR SOME ISOLATED THUNDER DUE TO SOME ELEVATED
INSTABILITY. ALSO ADJUSTED POPS DOWNWARD AFTER BETWEEN 12-14Z DUE TO
CURRENT RADAR/HI RES MODEL TRENDS.
HAD TO ADJUST LOWS SLIGHTLY UPWARD ALONG/SE OF NATCHEZ TRACE DUE TO
MID/HIGH CLOUDS. ADJUSTED HOURLY TEMPS/DEWPOINTS/SKY GRIDS TO
CURRENT TRENDS. REST OF THE FORECAST IS ON TRACK. /DC/
&&
.AVIATION...
VFR CONDITIONS WERE BEING REPORTED AT ALL TAF SITES AT
01Z SUN. VFR CONDS WL CONT THROUGH 06Z AS MID/HIGH LEVEL CLOUDS
INCREASE BUT AFTER 06Z CIGS WL LOWER FROM THE SOUTHEAST TO MVFR
CONDS AND IFR CIGS WL BE PSBL AROUND 12Z. RAIN SHOULD HOLD OFF UNTIL
AFTER 12Z AND INCREASE FROM THE SOUTH SUNDAY. THE BULK OF THE RAIN
WL FALL OVER THE SOUTHEAST. VSBYS MAY TEMPORARILY LOWER MVFR WITH
THE RAIN BUT OTHERWISE...CIGS SHOULD RISE ABOVE 3KFT AGAIN BY 17Z.
/22/
&&
.PREV DISCUSSION... /ISSUED 347 PM CDT SAT SEP 27 2014/
DISCUSSION...TONIGHT THROUGH SUNDAY NIGHT...INCREASING CHANCES FOR
RAIN ARE EXPECTED ACROSS THE CWA LATE TONIGHT...CONTINUING THROUGH
AT LEAST THE FIRST HALF OF SUNDAY...BEFORE DECREASING OVER THE
EASTERN HALF OF THE AREA SUNDAY NIGHT. ALL OF THIS IS THANKS TO
INCREASING MID/UPPER LEVEL MOISTURE AND LIFT ASSOCIATED WITH THE
COMBINATION OF A WEAK EASTERLY TOPICAL WAVE...AN APPROACHING TROUGH
FROM THE WEST...AND A WEAK LOW THAT`S FORECAST TO DEVELOP AND LIFT
NORTHWARD OVERNIGHT. THE BEST CHANCES FOR RAIN LOOK TO BE OVER EAST
AND SOUTHEAST MISSISSIPPI BOTH OVERNIGHT THROUGH SUNDAY AFTERNOON
WHERE THE BEST MOISTURE TRANSPORT ALOFT LOOKS TO EXIST AS THE WEAK
LOW LIFTS NORTHEAST NEAR THE EASTERN HALF OF THE CWA.
AS IT CURRENTLY STANDS...DUE TO THE OVERALL ELEVATED SETUP OF THIS
SYSTEM OVER OUR AREA...IN ADDITION TO SOIL CONDITIONS ACROSS THE
ENTIRE CWA BEING QUITE DRY DUE TO OUR OVERALL LACK OF RAIN...I
FOLLOWED SUITE OF THE PREVIOUS FORECAST IN BACKING OFF A BIT ON THE
FLASH FLOODING POTENTIAL. GUT FEELING THOUGH WAS TO COMPLETELY
REMOVE IT FROM THE HWO AND ASSOCIATED GRAPHICS.
HOWEVER...WILL CONTINUE TO WALK THE LINE AND ERR ON THE SIDE OF
CAUTION DUE TO ONGOING MODEL INCONSISTENCIES. IN OTHER WORDS...IF THE
NORTHWARD LIFTING LOW DEVELOPS JUST A LITTLE FURTHER WEST THAN
CURRENTLY FORECAST...SOME OF THE BETTER LIFT AND DEEPER TROPICAL
MOISTURE COULD MOVE UP ACROSS THE INTERSTATE 59 CORRIDOR CREATING A
BETTER POTENTIAL FOR A LONGER DURATION OF HEAVY RAINFALL THERE. BOTH
THE HWO AND GRAPHICS WERE ADJUSTED ACCORDINGLY WITH ANY HEAVY RAIN
POTENTIAL SHIFTED FURTHER EAST.
ACTIVITY IS EXPECTED TO GRADUALLY TAPER FROM WEST TO EAST ACROSS THE
FORECAST AREA FROM WEST TO EAST THROUGH THE AFTERNOON SUNDAY...WITH
SOME LIGHT SHOWERS LINGERING OVER NAMELY EAST MISSISSIPPI SUNDAY
NIGHT. /19/
MONDAY THROUGH SATURDAY...THE PERIOD WILL START WITH THE REGION
REMAINING UNDER THE INFLUENCE OF THE SHORTWAVE TROUGH BUT AS IT IS
DEPARTING. SOME SHOWERS WILL BE POSSIBLE IN THE EAST EARLY WITH
DRYING CONDITIONS IN THE WEST. THE UPPER TROUGH WILL MOVE THROUGH ON
MONDAY AFTERNOON...CLEARING SKIES THROUGH THE DAY FROM WEST TO EAST.
SHORTWAVE RIDGING WILL MOVE INTO THE REGION FOR TUESDAY THROUGH
THURSDAY. MUCH DRIER AIR WILL BE IN PLACE AS PW VALUES HOVER AROUND
AN INCH. TEMPERATURES NEXT WEEK WILL BEGIN A LITTLE COOLER DUE TO
RAIN AND CLOUD COVER AND THE LINGERING TROUGH BUT READINGS WILL
MODERATE TO NEAR NORMAL BY MID TO LATE WEEK.
MOISTURE WILL STEADILY INCREASE OVER THE REGION AND PW VALUES
WILL BE NEARING 2 INCHES BY EARLY FRIDAY MORNING. SOME SHOWERS MAY
BE POSSIBLE IN THE SOUTH AS MOISTURE INCREASES OVER THE AREA.
HOWEVER...THE BETTER CHANCE FOR RAIN WILL COME FRIDAY INTO SATURDAY
AS A COLD FRONT WILL CROSS THE REGION. MODELS ARE COMING INTO BETTER
ALIGNMENT IN THE TIMING AND PHASING OF THE COLD FRONT AND UPPER
LEVEL SYSTEM. BOTH THE GFS AND ECMWF DEPICT THE FRONT GENERALLY
COMING THROUGH ON FRIDAY ALONG WITH SHOWERS AND STORMS. THERE ARE
STILL SOME TIMING AND INTENSITY DIFFERENCES AS THE ECMWF DOESNT DIG
THE TROUGH NEARLY AS MUCH AS THE GFS...THUS PUSHING IT THROUGH
SOONER. REGARDLESS...OUR BEST CHANCES FOR RAIN AND STORMS WILL BE ON
FRIDAY. BEHIND THE FRONT...SIGNIFICANTLY DRIER AIR WILL MOVE IN WITH
MODELS SHOWING PW VALUES AROUND 0.3 INCHES. HIGHS ON SATURDAY SHOULD
BE VERY PLEASANT FOR OUTDOOR ACTIVITIES AND FOOTBALL GAMES WITH
READINGS IN THE 70S. OVERNIGHT LOWS WILL DIP INTO THE 50S. FALL WILL
DEFINITELY BE IN THE AIR AS THIS LOOKS TO BE THE BEST COOL SNAP
SINCE THE SPRING. /28/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 68 81 65 84 / 13 50 25 8
MERIDIAN 67 79 63 82 / 21 71 42 13
VICKSBURG 65 84 63 85 / 12 25 19 6
HATTIESBURG 70 79 67 85 / 43 70 24 7
NATCHEZ 67 83 66 85 / 11 29 13 7
GREENVILLE 63 83 64 85 / 11 16 15 6
GREENWOOD 63 83 63 85 / 11 22 20 7
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
DC/22/19/28
AREA FORECAST DISCUSSION
NWS BILLINGS MT
258 PM MDT FRI SEP 26 2014
.SHORT TERM...VALID FOR SAT AND SUN...
COLD FRONT HAS OOZED THROUGH MOST OF THE AREA BUT WITH STRONGER
COLD ADVECTION NOT OCCURRING UNTIL TONIGHT. TEMPS HAVE WARMED INTO
THE 80S AND LOWER 90S THIS AFTERNOON...WITH 2PM TEMP OF 93F AT
SHERIDAN TYING A RECORD FOR THE DAY. BILLINGS WINDS HAVE SHIFTED
TO THE NE AND LOW LEVEL CONVERGENT AREA LONG WITH WEAK ENERGY FROM
THE SW ALLOWING FOR A CU FIELD TO FORM FROM BILLINGS WEST...WITH
LATEST RADAR SHOWING WEAK ECHOES IN PARK AND SWEET GRASS
COUNTIES. AREAS FROM BILLINGS WEST CAN EXPECT ISOLATED SHOWERS/
TSTMS THROUGH THE EARLY EVENING HOURS...THIS REMAINS CONSISTENT
WITH RECENT HRRR RUNS...WITH THE EAST REMAINING DRY/CLEAR. MAIN
FORECAST ISSUE CONTINUES TO REVOLVE AROUND DEEP PACIFIC TROF WHICH
IS PUSHING SLOWLY INLAND AND WILL BEGIN TO IMPACT OUR WEST LATER
TONIGHT.
OVERALL THEME OF FORECAST REMAINS UNCHANGED TODAY. PCPN CHANCES
WILL INCREASE WEST OF BILLINGS LATER TONIGHT...WITH RAIN LIKELY
WEST OF BILLINGS SATURDAY...THEN BECOMING LIKELY ACROSS THE CWA
SATURDAY NIGHT THROUGH SUNDAY NIGHT AS UPPER LOW SHIFTS TO OUR
SOUTH LEAVING OUR REGION IN A FAVORABLE DIFFLUENT REGION ALOFT.
HAVE ADJUSTED POPS A BIT...WITH THE MAIN CHANGE BEING TO DRY OUT
BILLINGS ON SATURDAY. STRONGER FORCING SHOULD STAY TO OUR WEST...
WITH COOLER LOW LEVEL NE WINDS KEEPING OUR AIRMASS STABLE WITH
WITH A 5-6KFT CLOUD DECK. THIS MAY SUPPORT A FEW SPRINKLES BUT
SHOULD NOT BE ANYTHING MORE THAN THAT IF YOU ARE PLANNING TO BE
OUTDOORS IN BILLINGS ON SATURDAY. OTHER CHANGE WAS TO RAISE POPS
NEAR SHERIDAN AND LAME DEER SUNDAY NIGHT AS ALL MODELS SHOW
STRONGER PIECE OF ENERGY LIFTING OUT OF WYOMING. COULD ALSO BE
SOME TSTMS WITH ELEVATED INSTABILITY IN OUR SOUTHEAST.
IMPACTS WITH THIS SYSTEM WILL NOT BE GREAT. COULD SEE SOME WET
SNOW OVER THE HIGHEST PEAKS INCLUDING BEARTOOTH PASS BY SATURDAY
NIGHT...BUT SNOW LEVELS LOOK TO STAY UP NEAR 10KFT. OTHERWISE WE
ARE TALKING ABOUT A COUPLE DAYS OF MUCH COOLER AND OCCASIONALLY
WET WEATHER...WITH PCPN TOTALS NEAR AN INCH IN PLACES BY SUNDAY
NIGHT ESPECIALLY IN OUR WESTERN UPSLOPE AREAS...ALONG WITH A
HEALTHY NE WIND. THOUGH IT WILL BE A COLD RAIN...DO NOT THINK
FOOTHILL LOCATIONS SUCH AS RED LODGE AND STORY WILL SEE SNOW THIS
TIME.
AFTER NEAR RECORD HEAT AGAIN TODAY WE WILL SEE TEMPS DROP
SIGNIFICANTLY FOR SATURDAY AND CLOSER TO LATE SEPTEMBER NORMALS.
SUNDAY WILL BE EVEN COOLER WITH HIGHS ONLY IN THE UPPER 40S AND
50S ACROSS MOST LOWER ELEVATIONS.
JKL
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
LARGE UPPER TROUGH WILL BE TRACKING THROUGH THE NORTHERN AND
CENTRAL ROCKIES TO START THE EXTENDED. MODELS HAVE COME INTO GOOD
AGREEMENT THROUGH MONDAY NIGHT...BUT HAVE SOME SIGNIFICANT AND
CRITICAL DIFFERENCES THROUGH TUESDAY EVENING.
A STRONG SHORT WAVE WILL LIFT ACROSS THE FORECAST AREA FROM THE
SOUTH ON THE FRONT SIDE OF THE TROUGH MONDAY. MODELS VERY MUCH IN
AGREEMENT SO ADJUSTED POPS FOR THIS FEATURE WHICH HITS MAINLY
EASTERN ZONES. GFS THEN HAS UPPER CLOSED LOW THAT LIFTS THROUGH SE
MONTANA MONDAY NIGHT INTO TUESDAY WHILE ECMWF KEEPS SYSTEM OPEN
AND TRACKS IT FURTHER SOUTH. THE GFS SOLUTION IS THUS MUCH MORE
BULLISH WITH SIGNIFICANT QPF OVER OUR EAST TUESDAY DUE TO TROWAL
TYPE DEVELOPMENT...BUT THE ECMWF SCENARIO KEEPS THE FORCING IN
THE DAKOTAS. GEM ALSO KEEPS WAVE OPEN SIMILAR TO THE ECMWF. I HAVE
THEREFORE USED A BLEND WHILE LEANING TOWARD THE LESS AGGRESSIVE
ECMWF SOLUTION.
THE LONG WAVE PATTERN REMAINS CYCLONIC THE REST OF THE WORK WEEK
WITH THE MODELS HAVING DIFFERENCES TRYING TO TIME SOME SHORT WAVES
WITHIN THE MEAN FLOW. SO SOME UNSETTLED WEATHER IS EXPECTED WITH
SEASONABLE TEMPERATURES. BT
&&
.AVIATION...
VFR CONDITIONS WILL GENERALLY PREVAIL THROUGH THIS EVENING.
HOWEVER...LOCAL MVFR CONDITIONS ARE POSSIBLE TONIGHT DUE TO
LOWERED VISIBILITY IN SHOWERS AND THUNDERSTORMS...MAINLY FROM KBIL
WEST AND SOUTH INTO THE BEARTOOTHS. SURFACE WINDS WILL BECOME
NORTHEAST THIS EVENING AND BRISK INTO SATURDAY. BT
&&
.PRELIMINARY POINT TEMP/POPS...
SAT SUN MON TUE WED THU FRI
-----------------------------------------------------------
BIL 055/065 045/054 043/064 049/066 045/060 042/057 042/064
21/E 66/W 63/W 22/W 22/W 02/W 20/U
LVM 050/059 045/055 040/064 044/064 037/058 035/057 036/065
67/R 87/W 63/W 33/W 32/W 12/W 21/B
HDN 051/070 047/057 043/066 048/068 044/061 041/060 040/066
01/B 66/W 63/W 22/W 22/W 02/W 20/U
MLS 055/073 047/057 043/064 050/066 046/062 041/059 041/065
00/B 35/W 55/T 33/W 22/W 12/W 21/B
4BQ 055/076 049/060 044/065 051/064 044/059 039/058 039/063
00/U 24/T 64/T 33/T 22/W 12/W 21/U
BHK 055/077 048/058 041/061 050/064 044/060 039/057 037/060
00/U 24/W 55/T 74/T 22/W 12/W 21/B
SHR 052/073 048/057 042/066 046/065 042/056 037/057 036/064
00/B 35/T 73/W 23/W 22/W 02/W 20/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
702 PM CDT SAT SEP 27 2014
.SYNOPSIS...
ISSUED AT 310 PM CDT SAT SEP 27 2014
AT 19Z...WATER VAPOR IMAGERY SHOWED A DEEP TROUGH OVER THE WEST
COAST WITH A CLOSED LOW CENTERED OVER CENTRAL CALIFORNIA. MOISTURE
STREAMED NORTHWARD ON THE DOWNSTREAM SIDE OF THE TROUGH WHERE LOTS
OF CLOUD COVER AND THUNDERSTORMS WERE OBSERVED FROM ARIZONA INTO
MONTANA. STRONG RIDGING WAS IN PLACE ACROSS THE REMAINDER OF THE
COUNTRY WHILE A CUTOFF UPPER LOW SPUN OVER WESTERN IOWA.
TEMPERATURES ACROSS THE PLAINS HAVE SOARED TO WELL ABOVE NORMAL
LEVELS AS WARM AIR STREAMS NORTH UNDER THE RIDGE. BY EARLY
AFTERNOON...READINGS IN THE LOW TO MID 80S WERE COMMON FOR MUCH OF
THE DAKOTAS THROUGH THE SOUTHERN PLAINS...WITH LOCAL AREAS RANGING
FROM 80 TO 85 DEGREES.
SLIGHTLY COOLER AIR ALOFT WAS OBSERVED FROM THE VICINITY OF THE IOWA
UPPER LOW DOWN INTO TEXAS. THIS LED TO STEEPER LAPSE RATES...AND
THEREFORE HAVE OBSERVED DECENT CUMULUS FIELD DEVELOP THIS
AFTERNOON.
THE UPPER LEVEL LOW ACROSS CA/NV THIS AFTN WILL LIFT THROUGH THE
ROCKIES AND INTO THE NRN PLAINS BY TUESDAY. A STRONG PACIFIC FRONT
WILL SWEEP THE FCST AREA MONDAY NIGHT AND TUESDAY PRODUCING HEAVY
RAIN ACROSS WRN NEB WITH LIGHTER AMOUNTS EAST. COOLER WEATHER
PREVAILS WEDNESDAY THROUGH SATURDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 310 PM CDT SAT SEP 27 2014
THE UPPER LOW OVER IOWA WILL STAY FAIRLY STATIONARY OR MAY EVEN
MEANDER WESTWARD SLIGHTLY TONIGHT. MODELS ARE SHOWING A WEAK IMPULSE
OF ENERGY ROTATING AROUND THE LOW...WHICH WOULD MOVE ACROSS THE
NORTHEAST PART OF THE FORECAST AREA AFTER 06Z TONIGHT. AT THE SAME
TIME...IT IS PROJECTED THAT THE LOW LEVEL JET WILL BE VEERING TO THE
NORTHEAST INTO THIS SAME AREA WHICH COULD BRING ENOUGH LIFT TO
DEVELOP SOME SHOWERS LATE TONIGHT AND EARLY SUNDAY MORNING.
TIME-FRAME LOOKS TO BE 09Z TO 15Z CURRENTLY. BELIEVE THERE WILL BE
DEVELOPMENT IN A NORTH TO SOUTH LINE SOMEWHERE FROM NORTH CENTRAL
INTO CENTRAL NEBRASKA. CONFIDENCE ISN/T REAL HIGH THOUGH IN
PLACEMENT AND AS COVERAGE WILL LIKELY BE ISOLATED TO
SCATTERED...HAVE SLIGHT CHANCES FOR SHOWERS IN THE FORECAST
CURRENTLY.
ALSO LOOKING AT POTENTIAL FOR FOG TONIGHT OVER THE WESTERN PART OF
THE FORECAST AREA. THE NAM IS HIGHLIGHTING A STRONG INCREASE IN LOW
LEVEL MOISTURE MAINLY WEST OF HIGHWAY 83 WHILE THE GFS IS FURTHER
EAST. THAT BEING SAID...THE RAP KEEPS MINIMAL LOW LEVEL MOISTURE
OVER THE LOCAL AREA...AS IT KEEPS THE POTENTIAL BETTER OVER WESTERN
KANSAS. THESE DIFFERENCES MAINLY RELY ON THE PLACEMENT OF THE
SURFACE LOW. WITH LOWER CONFIDENCE...HAVE NOT ADDED FOG INTO THE
FORECAST AT THIS TIME...BUT WILL PASS ON POTENTIAL TO ONCOMING
SHIFT.
LOOKING THEN INTO SUNDAY...WITH THE THOUGHT THAT ANY FOG AND/OR
CLOUD COVER THAT MAY LINGER INTO THE MORNING HOURS WILL QUICKLY
DISSIPATE...TEMPERATURES ALOFT WILL BE SIMILAR TO TODAY...AND WITH
DEEP MIXING EXPECTED...SHOULD ONCE AGAIN SEE HIGHS IN THE 80S.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 310 PM CDT SAT SEP 27 2014
SUNDAY NIGHT THROUGH TUESDAY...THE ECM AND NAM ARE THE SLOWEST SOLNS
WITH THE PASSAGE OF THE PACIFIC FRONT MONDAY NIGHT AND TUESDAY. THUS
RAIN CHANCES ARE DELAYED UNTIL EARLY MONDAY MORNING. IT IS POSSIBLE
THE FASTER AND STRONGER GFS/GEM SOLNS ARE A BETTER FCST BUT GIVEN
THE MODELS HAVE BEEN TRENDING SLOWER OVERALL...THE NAM/ECM APPEARS TO
BE THE BEST FIT.
A SOLID PV ANOMALY WILL BE APPROACHING THE FCST AREA MONDAY AFTN AND
THIS SHOULD PROVIDE AMPLE SUPPORT FOR SCATTERED TO NUMEROUS TSTMS
INTO THE EVENING. COLD AIR ALOFT AND PWS OVER 200 PERCENT OF NORMAL
ARE EXPECTED TO PRODUCE HEAVY RAIN...MAINLY ALONG AND WEST OF
HIGHWAY 61. THE NAM/ECM SOLN PRODUCES 1 TO 1.5 INCHES OF RAIN IN THE
WEST DOWN TO 1/4 INCH IN THE EAST. POPS ARE LIMITED TO THE LIKELY
CATEGORY FOR THIS FORECAST AS MODEL TIMING IS THE MAIN CONCERN FOR
THE FORECAST.
SOUTHEAST WINDS MONDAY INCREASE TO 25 MPH WITH GUSTS TO 35 MPH. THE
GFS/GEM MODELS SUGGEST 30 MPH WINDS GUSTING TO 40 MPH. THE MAX
TEMPERATURE FORECAST COOLS INTO THE UPPER 70S TO LOWER 80S. AN
INCREASE IN MID LEVEL CLOUDINESS IS EXPECTED WITH THE APPROACH OF
THE UPPER LOW.
SPC SUGGESTED AMPLE SHEAR WILL DEVELOP MONDAY AFTN AS SOUTHERLY
H500MB WINDS INCREASE TO 60 KT. THIS IS TRUE BUT COUPLED WITH THE
STRONG LOWER LEVEL SOUTHERLY WINDS...20 TO 30 KT...THE EFFECTIVE
SHEAR APPEARS WEAK NEAR 20 TO 30 KT AND THE NAM SOUNDINGS SUGGEST
NARROW CAPE. THE SIGNIFICANT SEVERE PARAMETER IN ALL SOLNS SEEMS TO
SUPPORT THE 5 PERCENT SEVERE WEATHER POTENTIAL MONDAY.
THE PACIFIC FRONT MOVES THROUGH THE FCST AREA TUESDAY. THE H500MB
COLD POOL CENTERED OVER SD SHOULD CONTINUE TO SUPPORT CONVECTION
ACROSS NRN NEB WITH HIGHS IN THE 60S TO LOWER 70S. THE 500M AGL
WINDS IN THE GFS...ECM AND GEM INCREASE TO OVER 30 KT ACROSS NRN NEB
DURING THE AFTN WHICH WOULD SUPPORT A WIND ADVISORY. THE 12Z ECM HAS
TRENDED TOWARD THE DEEPER GFS/GEM LOW PRESSURE SYSTEM SOLN. THE
STRONG WINDS DEVELOP IN CONJUNCTION WITH THE PV ANOMALY AND H700MB
WINDS OF 45 TO 55 KT SHOWN IN THESE MODELS.
TUESDAY NIGHT THROUGH SATURDAY...STRONG COLD FRONTS MOVE THROUGH
WEDNESDAY NIGHT AND THURSDAY NIGHT. BOTH SUGGEST A CHANCE OF
SHOWERS. THE SECOND COLD FRONT SENDS H850MB TEMPERATURES TO NEAR 0C
FRIDAY MORNING. HIGHS FRIDAY RISE INTO JUST THE 50S TO LOWER 60S
WHICH WOULD SUPPORT FROST SATURDAY MORNING BUT THIS HIGH MOVES OFF
VERY QUICKLY AND WARM AIR RETURNS TO THE FCST AREA FRIDAY NIGHT.
OTHERWISE HIGHS RISE INTO THE 60S AND 70S EACH DAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 700 PM CDT SAT SEP 27 2014
SOUTHERLY WINDS WILL DECREASE OVER WESTERN NEBRASKA TONIGHT. SOME
MIFG OR BR POSSIBLE OVER THE PLATTE RIVER VALLEY AROUND
28/12Z.VISIBILITIES EXPECTED IN VFR CATEGORIES. SOME LIGHT
RAINSHOWERS POSSIBLE BETWEEN KBBW AND KONL IN THE SAME TIME FRAME.
OTHERWISE VFR CONDITIONS WITH SOUTHERLY WINDS INCREASING AGAIN
SUNDAY AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BROOKS/CDC
SHORT TERM...BROOKS
LONG TERM...CDC
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1236 PM CDT FRI SEP 26 2014
.UPDATE...
ISSUED AT 958 AM CDT FRI SEP 26 2014
JUST COMPLETED THE FIRST MINOR UPDATE OF THE DAY. AS
EXPECTED...THERE WAS SOME PATCHY FOG MAINLY NORTH OF I-80 EARLY
THIS MORNING BUT IT WAS NOT NEARLY AS DENSE/IMPACTFUL AS THURS AM.
PRECIP-WISE...STILL EXPECTING A DRY DAY CWA-WIDE BUT AM KEEPING A
WARY EYE ON A SMATTERING OF MID-LEVEL CUMULUS THAT ARE SKIRTING
ACROSS THE YORK/POLK COUNTY AREA AT THIS TIME...AS THE MEANDERING
MID LEVEL LOW CENTERED JUST TO THE EAST OVER IA/MO SEEMS TO BE
JUST CLOSE ENOUGH TO KICK UP THESE CLOUDS...AND EVEN SOME ONGOING
ISOLATED SHOWERS CLOSER TO ITS CORE. TEMP-WISE...BASED ON WHAT
HAPPENED YESTERDAY WHEN HIGHS ROSE A FEW DEGREES WARMER THAN
EXPECTED...ALREADY DECIDED TO BUMP UP TODAYS HIGHS GENERALLY 1-2
DEGREES FROM PREVIOUS FORECAST IN SEVERAL AREAS. THIS COULD BRING
A BIT GREATER COVERAGE OF MID-80S VERSUS LOWER-80S...BUT THE VAST
MAJORITY OF THE CWA IS EXPECTED TO TOP OUT SOMEWHERE BETWEEN
82-86.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT FRI SEP 26 2014
DRY/QUIET WEATHER IS FORECAST THROUGH THE SHORT TERM PERIODS.
ALOFT...THE PATTERN FEATURED UPPER RIDGING FROM THE DESERT SOUTHWEST
THRU THE DAKOTAS/UPPER MIDWEST REGION...AND TO THE SOUTHEAST AN AREA
OF LOW PRESSURE WAS LOCATED IN NORTHERN MO/SOUTHERN IA. FARTHER
UPSTREAM...AN UPPER TROUGH WAS MOVING INLAND TO THE WEST COAST. AT
THE SURFACE...SOUTHERLY LLVL FLOW WAS IN PLACE IN BETWEEN A LOW
PRESSURE TROUGH ALONG THE HIGH PLAINS REGION AND A RIDGE WELL EAST
OF THE MO/MS RIVERS.
HAVE BEEN MONITORING OBSERVATIONAL DATA THE LAST SEVERAL HOURS FOR
SIGNS OF FOG DEVELOPMENT AS TEMP/DP SPREADS CLOSE IN...AND SO FAR
THE LOWEST VSBY RESTRICTION HAVE BEEN AROUND 7SM. SHORT TERM
FORECAST MODELS SUGGEST OUR NORTHERN ZONES INTO NE NEB STAND THE
BETTER CHC FOR THE LOWER VSBYS AND WILL CONTINUE TO MENTION PATCHY
FOG POTENTIAL HERE.
AS WE HEAD THROUGH THE DAY TODAY...THE UPPER LOW PRESSURE SYSTEM IN
KS IS PROGGED TO RETROGRADE/MEANDER TO THE NW INTO NORTHERN
IA/EASTERN NEB WHILE TO THE WEST...THE WESTERN CONUS TROUGH DEEPENS
WITH THE LOW CLOSING OFF IN CA. THE WEATHER REGIME WILL BECOME
BLOCKED DUE TO THE WESTERN TROUGH AND AN EAST COAST RIDGE...WITH
THE INTERIOR CONUS IN BETWEEN THE SYSTEMS. EXPECT DRY WEATHER TO
PREVAIL FOR OUR AREA...DESPITE THE RAP WHICH TRIES TO GENERATE
MINOR QPF/PCPN JUST TO OUR EAST IN ASSOCIATION WITH THE MEANDERING
UPPER LOW. HAVE INCREASED SKY GRIDS/CLOUDS TO SOME DEGREE
TODAY/TONIGHT WITH THE WESTWARD MOVING SYSTEM. OTHERWISE...MODEL
FORECAST SOUNDINGS SUGGEST MIXING THIS AFTN JUST ABOVE H85 WITH
WINDS AT THE TOP OF THE LAYER AROUND 20KTS. THE SFC GRADIENT ALSO
TIGHTENS AND EXPECT A PERIOD OF STEADY/GUSTY SOUTHERLY WINDS FOR A
FEW HOURS THIS AFTN. HARD TO ARGUE WITH CURRENT FORECAST TEMPS FOR
BOTH TODAY AND TONIGHT AND LITTLE CHANGES WERE MADE. AFTN HIGHS IN
THE LOW/MID 80S LOOK ON TARGET IN THE MILD FALL AIRMASS...WITH
LOWS STILL ABOVE NORMAL IN THE 50S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 317 AM CDT FRI SEP 26 2014
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS MONDAY
THROUGH THURSDAY AND TEMPERATURES.
SATURDAY THROUGH SUNDAY NIGHT THE MAIN FEATURE WILL BE AN UPPER
RIDGE THAT WILL KEEP SKIES MOSTLY CLEAR AND TEMPERATURES ON THE WARM
SIDE.
DURING THIS TIME AN UPPER LEVEL LOW DEVELOPS IN THE SOUTHWESTERN
CONUS. THE FIRST UPPER WAVE FROM THIS LOT WILL START TO AFFECT THE
AREA MAINLY DURING THE AFTERNOON ON MONDAY AND AS A SURFACE LOW AND
COLD FRONT MOVES THROUGH THE AREA MONDAY NIGHT WILL BE A GOOD CHANCE
FOR THUNDERSTORMS. SOME THUNDERSTORMS ARE POSSIBLE TUESDAY BEFORE
MOVING OUT OF THE AREA DURING THE NIGHT TUESDAY NIGHT. THE NEXT
UPPER WAVE WILL MOVE INTO THE AREA ON WEDNESDAY ALONG WITH A SURFACE
LOW AND COLD FRONT. THERE WILL BE CHANCES FOR THUNDERSTORMS
WEDNESDAY THROUGH THURSDAY AS THIS SYSTEM MOVES THROUGH.
TEMPERATURES WILL BE ON A GRADUAL COOL DOWN WITH TEMPERATURES
COOLING BACK TO BELOW NORMAL BY THURSDAY.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z SATURDAY)
ISSUED AT 1235 PM CDT FRI SEP 26 2014
CONFIDENCE IS ABOVE-AVERAGE IN VFR CEILING/VISIBILITY PREVAILING
THROUGH THE NEXT 24 HOURS...WITH IN FACT FEW IF ANY CLOUDS AND
ESSENTIALLY NIL RISK OF PRECIPITATION. SOUTHERLY SURFACE BREEZES
WILL AVERAGE A BIT STRONGER THAN THE PAST 24 HOURS...WITH GUST
POTENTIAL UP INTO THE 18-20KT RANGE BOTH THIS AFTERNOON AND AGAIN
LATE SATURDAY MORNING. MEANWHILE...LIGHTER SUSTAINED BREEZES ONLY
AROUND 10KT WILL PREVAIL THIS EVENING/TONIGHT. ONE POSSIBLE ISSUE
THAT WILL NEED MONITORED IN LATER FORECASTS IS THE STRENGTH OF
LOW LEVEL WIND SHEAR (LLWS) LATE TONIGHT...AS SOUTH WINDS ARE
FORECAST TO INCREASE INTO GENERALLY THE 35-38KT RANGE WITHIN THE
LOWEST SEVERAL HUNDRED FEET ABOVE THE SURFACE. HOWEVER...BECAUSE
THE DIFFERENCE IN OVERALL BULK SHEAR MAGNITUDE BETWEEN THE SURFACE
AND ROUGHLY 1000 FEET AGL IS CURRENTLY FORECAST TO ONLY AVERAGE
25-30KT AS OPPOSED TO 30+KT...HAVE DEEMED THIS JUST BELOW THE
MAGNITUDE WORTHY OF A FORMAL LLWS MENTION IN THE TAFS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...FAY
LONG TERM...JCB
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
958 AM CDT FRI SEP 26 2014
.UPDATE...
ISSUED AT 958 AM CDT FRI SEP 26 2014
JUST COMPLETED THE FIRST MINOR UPDATE OF THE DAY. AS
EXPECTED...THERE WAS SOME PATCHY FOG MAINLY NORTH OF I-80 EARLY
THIS MORNING BUT IT WAS NOT NEARLY AS DENSE/IMPACTFUL AS THURS AM.
PRECIP-WISE...STILL EXPECTING A DRY DAY CWA-WIDE BUT AM KEEPING A
WARY ON A SMATTERING OF MID-LEVEL CUMULUS THAT ARE SKIRTING ACROSS
THE YORK/POLK COUNTY AREA AT THIS TIME...AS THE MEANDERING MID
LEVEL LOW CENTERED JUST TO THE EAST OVER IA/MO SEEMS TO BE JUST
CLOSE ENOUGH TO KICK UP THESE CLOUDS...AND EVEN SOME ONGOING
ISOLATED SHOWERS CLOSER TO ITS CORE. TEMP-WISE...BASED ON WHAT
HAPPENED YESTERDAY WHEN HIGHS ROSE A FEW DEGREES WARMER THAN
EXPECTED...ALREADY DECIDED TO BUMP UP TODAYS HIGHS GENERALLY 1-2
DEGREES FROM PREVIOUS FORECAST IN SEVERAL AREAS. THIS COULD BRING
A BIT GREATER COVERAGE OF MID-80S VERSUS LOWER-80S...BUT THE VAST
MAJORITY OF THE CWA IS EXPECTED TO TOP OUT SOMEWHERE BETWEEN
82-86.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT FRI SEP 26 2014
DRY/QUIET WEATHER IS FORECAST THROUGH THE SHORT TERM PERIODS.
ALOFT...THE PATTERN FEATURED UPPER RIDGING FROM THE DESERT SOUTHWEST
THRU THE DAKOTAS/UPPER MIDWEST REGION...AND TO THE SOUTHEAST AN AREA
OF LOW PRESSURE WAS LOCATED IN NORTHERN MO/SOUTHERN IA. FARTHER
UPSTREAM...AN UPPER TROUGH WAS MOVING INLAND TO THE WEST COAST. AT
THE SURFACE...SOUTHERLY LLVL FLOW WAS IN PLACE IN BETWEEN A LOW
PRESSURE TROUGH ALONG THE HIGH PLAINS REGION AND A RIDGE WELL EAST
OF THE MO/MS RIVERS.
HAVE BEEN MONITORING OBSERVATIONAL DATA THE LAST SEVERAL HOURS FOR
SIGNS OF FOG DEVELOPMENT AS TEMP/DP SPREADS CLOSE IN...AND SO FAR
THE LOWEST VSBY RESTRICTION HAVE BEEN AROUND 7SM. SHORT TERM
FORECAST MODELS SUGGEST OUR NORTHERN ZONES INTO NE NEB STAND THE
BETTER CHC FOR THE LOWER VSBYS AND WILL CONTINUE TO MENTION PATCHY
FOG POTENTIAL HERE.
AS WE HEAD THROUGH THE DAY TODAY...THE UPPER LOW PRESSURE SYSTEM IN
KS IS PROGGED TO RETROGRADE/MEANDER TO THE NW INTO NORTHERN
IA/EASTERN NEB WHILE TO THE WEST...THE WESTERN CONUS TROUGH DEEPENS
WITH THE LOW CLOSING OFF IN CA. THE WEATHER REGIME WILL BECOME
BLOCKED DUE TO THE WESTERN TROUGH AND AN EAST COAST RIDGE...WITH
THE INTERIOR CONUS IN BETWEEN THE SYSTEMS. EXPECT DRY WEATHER TO
PREVAIL FOR OUR AREA...DESPITE THE RAP WHICH TRIES TO GENERATE
MINOR QPF/PCPN JUST TO OUR EAST IN ASSOCIATION WITH THE MEANDERING
UPPER LOW. HAVE INCREASED SKY GRIDS/CLOUDS TO SOME DEGREE
TODAY/TONIGHT WITH THE WESTWARD MOVING SYSTEM. OTHERWISE...MODEL
FORECAST SOUNDINGS SUGGEST MIXING THIS AFTN JUST ABOVE H85 WITH
WINDS AT THE TOP OF THE LAYER AROUND 20KTS. THE SFC GRADIENT ALSO
TIGHTENS AND EXPECT A PERIOD OF STEADY/GUSTY SOUTHERLY WINDS FOR A
FEW HOURS THIS AFTN. HARD TO ARGUE WITH CURRENT FORECAST TEMPS FOR
BOTH TODAY AND TONIGHT AND LITTLE CHANGES WERE MADE. AFTN HIGHS IN
THE LOW/MID 80S LOOK ON TARGET IN THE MILD FALL AIRMASS...WITH
LOWS STILL ABOVE NORMAL IN THE 50S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 317 AM CDT FRI SEP 26 2014
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS MONDAY
THROUGH THURSDAY AND TEMPERATURES.
SATURDAY THROUGH SUNDAY NIGHT THE MAIN FEATURE WILL BE AN UPPER
RIDGE THAT WILL KEEP SKIES MOSTLY CLEAR AND TEMPERATURES ON THE WARM
SIDE.
DURING THIS TIME AN UPPER LEVEL LOW DEVELOPS IN THE SOUTHWESTERN
CONUS. THE FIRST UPPER WAVE FROM THIS LOT WILL START TO AFFECT THE
AREA MAINLY DURING THE AFTERNOON ON MONDAY AND AS A SURFACE LOW AND
COLD FRONT MOVES THROUGH THE AREA MONDAY NIGHT WILL BE A GOOD CHANCE
FOR THUNDERSTORMS. SOME THUNDERSTORMS ARE POSSIBLE TUESDAY BEFORE
MOVING OUT OF THE AREA DURING THE NIGHT TUESDAY NIGHT. THE NEXT
UPPER WAVE WILL MOVE INTO THE AREA ON WEDNESDAY ALONG WITH A SURFACE
LOW AND COLD FRONT. THERE WILL BE CHANCES FOR THUNDERSTORMS
WEDNESDAY THROUGH THURSDAY AS THIS SYSTEM MOVES THROUGH.
TEMPERATURES WILL BE ON A GRADUAL COOL DOWN WITH TEMPERATURES
COOLING BACK TO BELOW NORMAL BY THURSDAY.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z SATURDAY)
ISSUED AT 507 AM CDT FRI SEP 26 2014
THE MAIN CONCERN FOR THE TAF PERIOD IS WHETHER OR NOT FOG WILL
DEVELOP OR NOT WITHIN THE NEXT HOUR SO. VSBYS FOR THE MOST PART
HAVE BEEN UP ALL NIGHT HOWEVER WITHIN THE LAST HOUR KODX DROPPED
TO ONE QUARTER SM IN FOG. GENERALLY THINK THE FOG IS RATHER
LOCALIZED BUT WILL LEAVE IN A TEMPO GROUP FOR A COUPLE OF HOURS.
OTHERWISE...LOOK FOR SOUTHERLY WINDS TO INCREASE AROUND 15KTS THIS
AFTN WITH GUSTS OF 20KTS POSSIBLE. THESE WINDS WILL SUBSIDE DURING
THE EVENING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...FAY
LONG TERM...JCB
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
519 AM CDT FRI SEP 26 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT FRI SEP 26 2014
DRY/QUIET WEATHER IS FORECAST THROUGH THE SHORT TERM PERIODS.
ALOFT...THE PATTERN FEATURED UPPER RIDGING FROM THE DESERT SOUTHWEST
THRU THE DAKOTAS/UPPER MIDWEST REGION...AND TO THE SOUTHEAST AN AREA
OF LOW PRESSURE WAS LOCATED IN NORTHERN MO/SOUTHERN IA. FARTHER
UPSTREAM...AN UPPER TROUGH WAS MOVING INLAND TO THE WEST COAST. AT
THE SURFACE...SOUTHERLY LLVL FLOW WAS IN PLACE IN BETWEEN A LOW
PRESSURE TROUGH ALONG THE HIGH PLAINS REGION AND A RIDGE WELL EAST
OF THE MO/MS RIVERS.
HAVE BEEN MONITORING OBSERVATIONAL DATA THE LAST SEVERAL HOURS FOR
SIGNS OF FOG DEVELOPMENT AS TEMP/DP SPREADS CLOSE IN...AND SO FAR
THE LOWEST VSBY RESTRICTION HAVE BEEN AROUND 7SM. SHORT TERM
FORECAST MODELS SUGGEST OUR NORTHERN ZONES INTO NE NEB STAND THE
BETTER CHC FOR THE LOWER VSBYS AND WILL CONTINUE TO MENTION PATCHY
FOG POTENTIAL HERE.
AS WE HEAD THROUGH THE DAY TODAY...THE UPPER LOW PRESSURE SYSTEM IN
KS IS PROGGED TO RETROGRADE/MEANDER TO THE NW INTO NORTHERN
IA/EASTERN NEB WHILE TO THE WEST...THE WESTERN CONUS TROUGH DEEPENS
WITH THE LOW CLOSING OFF IN CA. THE WEATHER REGIME WILL BECOME
BLOCKED DUE TO THE WESTERN TROUGH AND AN EAST COAST RIDGE...WITH
THE INTERIOR CONUS IN BETWEEN THE SYSTEMS. EXPECT DRY WEATHER TO
PREVAIL FOR OUR AREA...DESPITE THE RAP WHICH TRIES TO GENERATE
MINOR QPF/PCPN JUST TO OUR EAST IN ASSOCIATION WITH THE MEANDERING
UPPER LOW. HAVE INCREASED SKY GRIDS/CLOUDS TO SOME DEGREE
TODAY/TONIGHT WITH THE WESTWARD MOVING SYSTEM. OTHERWISE...MODEL
FORECAST SOUNDINGS SUGGEST MIXING THIS AFTN JUST ABOVE H85 WITH
WINDS AT THE TOP OF THE LAYER AROUND 20KTS. THE SFC GRADIENT ALSO
TIGHTENS AND EXPECT A PERIOD OF STEADY/GUSTY SOUTHERLY WINDS FOR A
FEW HOURS THIS AFTN. HARD TO ARGUE WITH CURRENT FORECAST TEMPS FOR
BOTH TODAY AND TONIGHT AND LITTLE CHANGES WERE MADE. AFTN HIGHS IN
THE LOW/MID 80S LOOK ON TARGET IN THE MILD FALL AIRMASS...WITH
LOWS STILL ABOVE NORMAL IN THE 50S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 317 AM CDT FRI SEP 26 2014
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS MONDAY
THROUGH THURSDAY AND TEMPERATURES.
SATURDAY THROUGH SUNDAY NIGHT THE MAIN FEATURE WILL BE AN UPPER
RIDGE THAT WILL KEEP SKIES MOSTLY CLEAR AND TEMPERATURES ON THE WARM
SIDE.
DURING THIS TIME AN UPPER LEVEL LOW DEVELOPS IN THE SOUTHWESTERN
CONUS. THE FIRST UPPER WAVE FROM THIS LOT WILL START TO AFFECT THE
AREA MAINLY DURING THE AFTERNOON ON MONDAY AND AS A SURFACE LOW AND
COLD FRONT MOVES THROUGH THE AREA MONDAY NIGHT WILL BE A GOOD CHANCE
FOR THUNDERSTORMS. SOME THUNDERSTORMS ARE POSSIBLE TUESDAY BEFORE
MOVING OUT OF THE AREA DURING THE NIGHT TUESDAY NIGHT. THE NEXT
UPPER WAVE WILL MOVE INTO THE AREA ON WEDNESDAY ALONG WITH A SURFACE
LOW AND COLD FRONT. THERE WILL BE CHANCES FOR THUNDERSTORMS
WEDNESDAY THROUGH THURSDAY AS THIS SYSTEM MOVES THROUGH.
TEMPERATURES WILL BE ON A GRADUAL COOL DOWN WITH TEMPERATURES
COOLING BACK TO BELOW NORMAL BY THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 507 AM CDT FRI SEP 26 2014
THE MAIN CONCERN FOR THE TAF PERIOD IS WHETHER OR NOT FOG WILL
DEVELOP OR NOT WITHIN THE NEXT HOUR SO. VSBYS FOR THE MOST PART
HAVE BEEN UP ALL NIGHT HOWEVER WITHIN THE LAST HOUR KODX DROPPED
TO ONE QUARTER SM IN FOG. GENERALLY THINK THE FOG IS RATHER
LOCCALLIZED BUT WILL LEAVE IN A TEMPO GROUP FOR A COUPLE OF HOURS.
OTHERWISE...LOOK FOR SOUTHERLY WINDS TO INCREASE AROUND 15KTS THIS
AFTN WITH GUSTS OF 20KTS POSSIBLE. THESE WINDS WILL SUBSIDE DURING
THE EVENING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...FAY
LONG TERM...JCB
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
323 AM CDT FRI SEP 26 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT FRI SEP 26 2014
DRY/QUIET WEATHER IS FORECAST THROUGH THE SHORT TERM PERIODS.
ALOFT...THE PATTERN FEATURED UPPER RIDGING FROM THE DESERT SOUTHWEST
THRU THE DAKOTAS/UPPER MIDWEST REGION...AND TO THE SOUTHEAST AN AREA
OF LOW PRESSURE WAS LOCATED IN NORTHERN MO/SOUTHERN IA. FARTHER
UPSTREAM...AN UPPER TROUGH WAS MOVING INLAND TO THE WEST COAST. AT
THE SURFACE...SOUTHERLY LLVL FLOW WAS IN PLACE IN BETWEEN A LOW
PRESSURE TROUGH ALONG THE HIGH PLAINS REGION AND A RIDGE WELL EAST
OF THE MO/MS RIVERS.
HAVE BEEN MONITORING OBSERVATIONAL DATA THE LAST SEVERAL HOURS FOR
SIGNS OF FOG DEVELOPMENT AS TEMP/DP SPREADS CLOSE IN...AND SO FAR
THE LOWEST VSBY RESTRICTION HAVE BEEN AROUND 7SM. SHORT TERM
FORECAST MODELS SUGGEST OUR NORTHERN ZONES INTO NE NEB STAND THE
BETTER CHC FOR THE LOWER VSBYS AND WILL CONTINUE TO MENTION PATCHY
FOG POTENTIAL HERE.
AS WE HEAD THROUGH THE DAY TODAY...THE UPPER LOW PRESSURE SYSTEM IN
KS IS PROGGED TO RETROGRADE/MEANDER TO THE NW INTO NORTHERN
IA/EASTERN NEB WHILE TO THE WEST...THE WESTERN CONUS TROUGH DEEPENS
WITH THE LOW CLOSING OFF IN CA. THE WEATHER REGIME WILL BECOME
BLOCKED DUE TO THE WESTERN TROUGH AND AN EAST COAST RIDGE...WITH
THE INTERIOR CONUS IN BETWEEN THE SYSTEMS. EXPECT DRY WEATHER TO
PREVAIL FOR OUR AREA...DESPITE THE RAP WHICH TRIES TO GENERATE
MINOR QPF/PCPN JUST TO OUR EAST IN ASSOCIATION WITH THE MEANDERING
UPPER LOW. HAVE INCREASED SKY GRIDS/CLOUDS TO SOME DEGREE
TODAY/TONIGHT WITH THE WESTWARD MOVING SYSTEM. OTHERWISE...MODEL
FORECAST SOUNDINGS SUGGEST MIXING THIS AFTN JUST ABOVE H85 WITH
WINDS AT THE TOP OF THE LAYER AROUND 20KTS. THE SFC GRADIENT ALSO
TIGHTENS AND EXPECT A PERIOD OF STEADY/GUSTY SOUTHERLY WINDS FOR A
FEW HOURS THIS AFTN. HARD TO ARGUE WITH CURRENT FORECAST TEMPS FOR
BOTH TODAY AND TONIGHT AND LITTLE CHANGES WERE MADE. AFTN HIGHS IN
THE LOW/MID 80S LOOK ON TARGET IN THE MILD FALL AIRMASS...WITH
LOWS STILL ABOVE NORMAL IN THE 50S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 317 AM CDT FRI SEP 26 2014
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS MONDAY
THROUGH THURSDAY AND TEMPERATURES.
SATURDAY THROUGH SUNDAY NIGHT THE MAIN FEATURE WILL BE AN UPPER
RIDGE THAT WILL KEEP SKIES MOSTLY CLEAR AND TEMPERATURES ON THE WARM
SIDE.
DURING THIS TIME AN UPPER LEVEL LOW DEVELOPS IN THE SOUTHWESTERN
CONUS. THE FIRST UPPER WAVE FROM THIS LOT WILL START TO AFFECT THE
AREA MAINLY DURING THE AFTERNOON ON MONDAY AND AS A SURFACE LOW AND
COLD FRONT MOVES THROUGH THE AREA MONDAY NIGHT WILL BE A GOOD CHANCE
FOR THUNDERSTORMS. SOME THUNDERSTORMS ARE POSSIBLE TUESDAY BEFORE
MOVING OUT OF THE AREA DURING THE NIGHT TUESDAY NIGHT. THE NEXT
UPPER WAVE WILL MOVE INTO THE AREA ON WEDNESDAY ALONG WITH A SURFACE
LOW AND COLD FRONT. THERE WILL BE CHANCES FOR THUNDERSTORMS
WEDNESDAY THROUGH THURSDAY AS THIS SYSTEM MOVES THROUGH.
TEMPERATURES WILL BE ON A GRADUAL COOL DOWN WITH TEMPERATURES
COOLING BACK TO BELOW NORMAL BY THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1205 AM CDT FRI SEP 26 2014
OVERALL QUIET WEATHER IS FORECAST FOR THE TAF PERIOD. WINDS WILL
REMAIN SOUTHERLY AND FAIRLY LIGHT THORUGH THE NIGHT AND THERE IS
SOME POTENTIAL FOR A MVFR VSBY TOWARD MORNING. SOUTHERLY WINDS
WILL INCREASE FOR A TIME AROUND MID DAY ON FRIDAY...AND ANY CLOUD
COVER SHOULD REMAIN AT VFR LEVELS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...FAY
LONG TERM...JCB
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1059 PM EDT SAT SEP 27 2014
.SYNOPSIS...
HIGH PRESSURE BUILDING FROM THE NORTH WILL BRING A DRYING TREND
THROUGH THE WEEKEND AS A COASTAL TROUGH WEAKENS OFFSHORE. A WET
FORECAST IS SHAPING UP FOR EARLY NEXT WEEK AS LOW PRESSURE MOVES
ACROSS THE SOUTHEAST. HIGH PRESSURE WILL RE-BUILD FROM THE NORTH
THROUGH MID WEEK...WITH A COLD FRONT MOVING IN AT THE END OF THE
WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 1045 PM SATURDAY...SOME TWEAKING OF SKY CONDITIONS FOR THIS
UPDATE. BASED ON LATEST SAT IMAGERY TRENDS...LOOKING AT MAINLY
HIGH AND SOME MID LEVEL CLOUDS FOR THE NC PORTION OVERNITE...
AND...ALL 3 DECKS FOR THE ILM SC PORTION OF THE CWA. WILL CONTINUE
WITH THE LOW CHANCE FOR -RA OR DRIZZLE FOR THE SC COUNTIES.
TWEAKED MINS A DEGREE OR 2 LOWER FOR THE ILM NC PORTIONS DUE TO
LESS CLOUDS...OTHERWISE NO EDITS NEEDED.
PREVIOUS DISCUSSION..............................................
AS OF 730 PM SATURDAY...LATEST LOCAL KLTX AND 88D MOSAIC KEEPS THE
MAIN PCPN SHIELD SOUTH OF CAPE FEAR. LATEST HRRR MODEL KEEPS ANY
ONSHORE MOVEMENT OF THE PCPN ACROSS THE ILM SC COUNTIES. AS A
RESULT...HAVE ADJUSTED POPS KEEPING THEM AT LOW CHANCE TO AFFECT
MAINLY THOSE SC COUNTIES OVERNIGHT. CLOUDINESS HAS BEEN ADJUSTED
UPWARDS DUE TO ONGOING VARIABLY SKY CONDITIONS AND THE TRAPPED
MOISTURE BELOW 700 MB AS ADVERTISED BY VARIOUS MODEL TIME HEIGHT
DISPLAYS ACROSS THE FA. MIN TEMPS SLIGHTLY TWEAKED...TOWARDS THE
UPWARD SIDE DUE TO MORE CLOUDINESS AND THREAT OF PCPN.
PREVIOUS DISCUSSION....................................
AS OF 3 PM SATURDAY...HIGH PRESSURE CONTINUES TO WEDGE DOWN THE
COAST THIS AFTN...INTERACTING WITH A COASTAL TROUGH THAT SEEMS TO
BE EVER-PRESENT JUST OFFSHORE. WEAK LOW PRESSURE OFF THE
CHARLESTON, SC COAST WILL CONTINUE TO DROP WEAKLY TO THE SOUTH
TONIGHT AS HIGH PRESSURE BECOMES MORE DOMINANT.
AREAS OF SHOWERS ALONG THE COASTAL TROUGH HAVE BEEN TRYING TO PUSH
ONSHORE TODAY...DRIVEN BY THE E/NE FLOW BETWEEN THE SURFACE WEDGE
AND COASTAL TROUGH. THE MID-LEVELS OF THE COLUMN...THOSE ABOVE
750MB...ARE VERY DRY...AND THE CONTINENTAL AIR MASS IS DRIER THAN
THAT OFFSHORE. THIS IS PRECLUDING MOST OF THE SHOWER ACTIVITY FROM
MAKING IT ONSHORE...BUT CANNOT RULE OUT SOME ISOLATED LIGHT
SHOWERS THROUGH TONIGHT...FOCUSED ALONG THE COAST...WITH BEST
CHANCE ALONG THE GRAND STRAND AND DOWN TOWARDS THE SOUTH SANTEE
RIVER. THE NAM FORECAST PROFILES ARE HANDLING THE CLOUD COVER BEST
TODAY...SO USING THIS AS A GUIDE EXPECT LOW LEVEL CLOUDINESS TO
PERSIST INTO TONIGHT. AS THE HIGH BECOMES MORE STRONGLY ENTRENCHED
LOCALLY CLOUD COVER WILL WANE...BUT EXPECT ONCE AGAIN QUITE A BIT
OF STRATUS AROUND TONIGHT. THIS WILL LIMIT OVERALL COOLING AND
HAVE AGAIN SIDED WITH THE LAV NUMBERS...AND AM FORECASTING LOWS
AROUND 60 IN THE FAR WESTERN ZONES...TO NEAR 70 ALONG THE GRAND
STRAND.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...UPPER RIDGE OVER EASTERN CONUS BREAKS DOWN
THROUGH THE SHORT TERM AS A SERIES OF STRONG SHORT WAVES DROP
ACROSS NEW ENGLAND AND THE GREAT LAKES REGION. THE SURFACE PICTURE
IS A LITTLE MUDDLED DUE TO A WEAK PRESSURE PATTERN AND A
DIVERGENCE OF MODEL SOLUTIONS. HOWEVER...A CONSENSUS OF GUIDANCE
HAS A FRONTAL SYSTEM DRAPED ACROSS THE DEEP SOUTH ON SUNDAY
LIFTING NORTH ON MONDAY INTO COASTAL GEORGIA AND SOUTH CAROLINA.
INCREASING MOISTURE ADVECTION WILL MAKE FOR A CLOUDY MONDAY WITH
POPS STEADILY INCREASING FROM SLIGHT CHANCE IN THE MORNING TO
LIKELY OVERNIGHT. SUNDAY HOWEVER LOOKS TO BE A DECENT DAY WITH
MINIMAL CHANCES OF PRECIP AND A GOOD BIT OF SUN...ESPECIALLY EARLY
ON. DAYTIME HEATING WILL LIKELY POP A CU FIELD IN THE
AFTERNOON...AND THE CIRRUS SHIELD WILL STEADILY INCREASE IN
ADVANCE OF MONDAYS FRONTAL SYSTEM. TEMPERATURES WILL BE QUITE
SEASONAL THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 3 PM SATURDAY...FORECAST MODELS FOR THE MEDIUM RANGE ARE IN
DECENT AGREEMENT ON THE SYSTEM MOVING ACROSS THE SOUTHEAST DURING
THE FIRST COUPLE OF DAYS. BOTH THE GFS AND ECMWF OPERATIONAL
MODELS SHOW A RATHER LETHARGIC SHORTWAVE THAT WAVERS BETWEEN AN
OPEN WAVE AND CLOSED LOW. I HAVE MAINTAINED THE GOOD CHANCE OF
SHOWERS FOR THE FIRST PART OF TUESDAY TRENDING DOWN THEREAFTER.
THE AFOREMENTIONED OPERATIONAL MODELS DIVERGE WITH REGARDS TO THE
MID LEVEL PATTERN FOR THE REMAINDER OF THE PERIOD. THE GFS KEEPS A
WEAKNESS AROUND THE AREA...MUCH LIKE WE HAVE SEEN THIS WEEK WHILE
THE ECMWF HAS A MORE PROGRESSIVE SOLUTION. WPC FAVORS MORE
BLENDING WITH ECMWF SOLUTIONS SO I HAVE BACKED OFF THE SLIGHT
CHANCE POPS LINGERING INTO WEDNESDAY AND THURSDAY. BEYOND THIS...A
STRONG SHORTWAVE MOVING THROUGH THE OHIO VALLEY AND ATTENDANT COLD
FRONT MOVE ACROSS LATE FRIDAY AND SATURDAY. AT THIS POINT THE
FRONT LOOKS TO BE MOISTURE STARVED AND INTRODUCED LOWER CHANCE
POPS FOR THE NEW DAY OF THE FORECAST PERIOD...SATURDAY.
REGARDING TEMPERATURES...I GENERALLY ADDED A DEGREE OR TWO ACROSS
THE BOARD TO WPC GUIDANCE AS THE WESTERLY FLOW THAT IS FORECAST TO
DEVELOP SHOULD ALLOW A DOWNSLOPE COMPONENT TO WARRANT. HOWEVER
MOST VALUES ARE WITHIN A FEW DEGREES OF CLIMATOLOGY.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...LINGERING MVFR CIGS AT KCRE/KMYR OVER THE NEXT FEW
HOURS...AND POSSIBLY AGAIN ALONG THE COAST JUST BEFORE DAYBREAK.
OTHERWISE EXPECT VFR AS HIGH PRESSURE CONTINUES TO BUILD ACROSS THE
AREA WITH A WEAKENING COASTAL TROUGH OFFSHORE.
LATEST RADAR DEPICTS LIGHT SHOWERS OFFSHORE BUT AS THEY CONTINUE TO
MOVE TOWARDS THE COAST...THEY CONTINUE TO WEAKEN AND ESSENTIALLY
DISSIPATE. LATEST OBS INDICATE VFR PREVAILS ACROSS THE AREA THIS
EVENING WITH THE EXCEPTION OF MVFR DUE TO LOW CIGS AT KMYR.
ANTICIPATE POSSIBILITY OF MVFR DUE TO LOW CIGS TO LINGER OVER THE
NEXT FEW HOURS AT KCRE/KMYR...AND THE POSSIBLY RE-OCCUR BEFORE
DAYBREAK ALONG THE COAST. OTHERWISE EXPECT VFR THROUGH THE OVERNIGHT
HOURS WITH NORTHEAST WINDS 5 TO 10 KTS. ON SUNDAY...ANY MVFR DUE TO
LOW CIGS COULD LINGER INTO THE LATE MORNING HOURS...BUT CONDITIONS
WILL GRADUALLY IMPROVE TO VFR WITH PERSISTENT NORTHEAST WINDS.
EXTENDED OUTLOOK...CHANCE OF SHOWERS/MVFR MONDAY AND TUESDAY AS LOW
PRESSURE MOVES ACROSS THE SOUTHEAST. MVFR/IFR CIGS ON WEDNESDAY/
POSSIBLY THURSDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM SATURDAY...SCEC ALL WATERS TO CONTINUE. TWEAKED
NE WINDS A KNOT OR 3 HIER BASED ON LATEST TRENDS AND 1ST LOOK AT
00Z GUIDANCE. SIG. SEAS TO RUN 3 TO 5 FT...EXCEPT A FOOT LOWER
SOUTH OF CAPE FEAR TO LITTLE RIVER INLET DUE TO THE SHADOW EFFECTS
FROM A NE WIND AND THE CONFIGURATION OF THE COASTLINE.
PREVIOUS DISCUSSION.............................................
AS OF 730 PM SATURDAY...SCA WILL BE LOWERED TO SCEC FOR THE ILM NC
WATERS...AND A SCEC WILL REMAIN IN EFFECT FOR THE ILM SC WATERS.
THE SCEC FOR ALL WATERS WILL REMAIN IN EFFECT THRU MIDDAY SUNDAY.
MODESTLY TIGHTENED SFC PG ACROSS THE WATERS WILL PRODUCE NE 15 TO
OCCASIONALLY 20 KT OF WINDS OVERNIGHT. SIGNIFICANT SEAS WILL RUN 3
TO 5 FT...EXCEPT 2 TO 4 FT SOUTH OF CAPE FEAR TO LITTLE RIVER
INLET. DOMINANT PERIODS WILL RUN 5 TO 6 SECONDS. NOT MUCH OF ANY
GROUND SWELL TO SPEAK OF.
PREVIOUS DISCUSSION...................................
AS OF 3 PM SATURDAY...HIGH PRESSURE WEDGING DOWN THE COAST AND A
COASTAL TROUGH POSITIONED ABOUT 50 MILES OFFSHORE...CONTINUE TO
KEEP THE COASTAL WATERS PINCHED IN BETWEEN. THIS IS CREATING GUSTY
NE WINDS OF 15-25 KTS...AND SEAS OF 3 TO 6 FT THIS AFTN. A SLOW
DECREASE IN WIND SPEEDS IS EXPECTED TONIGHT AS THE HIGH PRESSURE
PUSHES FURTHER SOUTH...WEAKENING THE GRADIENT...BUT SPEEDS OF
10-20 KTS WILL REMAIN INTO SUNDAY MORNING. HOWEVER...THE SLIGHTLY
LOWER SPEEDS WILL ALLOW WAVE HEIGHTS TO DROP TO BELOW 6 FT...AND
THE SCA SHOULD BE ABLE TO EXPIRE AT 8PM FOR THE NORTHERN WATERS.
THEREAFTER...A SCEC MAY BE NEEDED FOR THE MUCH OF THE REST OF THE
NEAR TERM AS SEAS ARE FORECAST TO REMAIN 3-5 FT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...NORTHEAST WINDS OF 10 TO 15 KTS ON SUNDAY
WILL DECREASE TO AROUND 10 KTS OR LESS ON MONDAY AS OVERALL
PRESSURE GRADIENT SLACKENS. SEAS OF AROUND 3 FT ON SUNDAY WILL
DECREASE TO AROUND 2 FT ON MONDAY.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 3 PM SATURDAY...A MODEST NORTHEASTERLY FLOW WILL GREET
MARINERS TUESDAY MORNING ALONG WITH WIDESPREAD RAINFALL. WIND
SPEEDS WILL BE LIGHT INITIALLY...LESS THAN TEN KNOTS. AS WE
PROGRESS INTO EARLY WEDNESDAY...THE FLOW WILL BACK TO MORE OF A
DUE NORTHERLY DIRECTION AND INCREASE TO 10-15 KNOTS AS THE LOW
PRESSURE SYSTEM PULLS AWAY SLOWLY. BY THE END OF THE PERIOD WINDS
ARE BACK TO A NORTHEAST DIRECTION AS HIGH PRESSURE BUILDS DOWN
FROM THE CANADIAN MARITIMES. SIGNIFICANT SEAS SHOULD BE ON THE LOW
SIDE CITING THE LACK OF STRONG WINDS AND CHANGES IN THE
FETCH...GENERALLY 1-3 TO 2-4 FEET.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...REK
NEAR TERM...DCH/JDW
SHORT TERM...REK
LONG TERM...SHK
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
817 PM EDT SAT SEP 27 2014
.SYNOPSIS...
HIGH PRESSURE BUILDING FROM THE NORTH WILL BRING A DRYING TREND
THROUGH THE WEEKEND AS A COASTAL TROUGH WEAKENS OFFSHORE. A WET
FORECAST IS SHAPING UP FOR EARLY NEXT WEEK AS LOW PRESSURE MOVES
ACROSS THE SOUTHEAST. HIGH PRESSURE WILL RE-BUILD FROM THE NORTH
THROUGH MID WEEK...WITH A COLD FRONT MOVING IN AT THE END OF THE
WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 730 PM SATURDAY...LATEST LOCAL KLTX AND 88D MOSAIC KEEPS THE
MAIN PCPN SHIELD SOUTH OF CAPE FEAR. LATEST HRRR MODEL KEEPS ANY
ONSHORE MOVEMENT OF THE PCPN ACROSS THE ILM SC COUNTIES. AS A
RESULT...HAVE ADJUSTED POPS KEEPING THEM AT LOW CHANCE TO AFFECT
MAINLY THOSE SC COUNTIES OVERNIGHT. CLOUDINESS HAS BEEN ADJUSTED
UPWARDS DUE TO ONGOING VARIABLY SKY CONDITIONS AND THE TRAPPED
MOISTURE BELOW 700 MB AS ADVERTISED BY VARIOUS MODEL TIME HEIGHT
DISPLAYS ACROSS THE FA. MIN TEMPS SLIGHTLY TWEAKED...TOWARDS THE
UPWARD SIDE DUE TO MORE CLOUDINESS AND THREAT OF PCPN.
PREVIOUS DISCUSSION...............................................
AS OF 3 PM SATURDAY...HIGH PRESSURE CONTINUES TO WEDGE DOWN THE
COAST THIS AFTN...INTERACTING WITH A COASTAL TROUGH THAT SEEMS TO
BE EVER-PRESENT JUST OFFSHORE. WEAK LOW PRESSURE OFF THE
CHARLESTON, SC COAST WILL CONTINUE TO DROP WEAKLY TO THE SOUTH
TONIGHT AS HIGH PRESSURE BECOMES MORE DOMINANT.
AREAS OF SHOWERS ALONG THE COASTAL TROUGH HAVE BEEN TRYING TO PUSH
ONSHORE TODAY...DRIVEN BY THE E/NE FLOW BETWEEN THE SURFACE WEDGE
AND COASTAL TROUGH. THE MID-LEVELS OF THE COLUMN...THOSE ABOVE
750MB...ARE VERY DRY...AND THE CONTINENTAL AIR MASS IS DRIER THAN
THAT OFFSHORE. THIS IS PRECLUDING MOST OF THE SHOWER ACTIVITY FROM
MAKING IT ONSHORE...BUT CANNOT RULE OUT SOME ISOLATED LIGHT
SHOWERS THROUGH TONIGHT...FOCUSED ALONG THE COAST...WITH BEST
CHANCE ALONG THE GRAND STRAND AND DOWN TOWARDS THE SOUTH SANTEE
RIVER. THE NAM FORECAST PROFILES ARE HANDLING THE CLOUD COVER BEST
TODAY...SO USING THIS AS A GUIDE EXPECT LOW LEVEL CLOUDINESS TO
PERSIST INTO TONIGHT. AS THE HIGH BECOMES MORE STRONGLY ENTRENCHED
LOCALLY CLOUD COVER WILL WANE...BUT EXPECT ONCE AGAIN QUITE A BIT
OF STRATUS AROUND TONIGHT. THIS WILL LIMIT OVERALL COOLING AND
HAVE AGAIN SIDED WITH THE LAV NUMBERS...AND AM FORECASTING LOWS
AROUND 60 IN THE FAR WESTERN ZONES...TO NEAR 70 ALONG THE GRAND
STRAND.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...UPPER RIDGE OVER EASTERN CONUS BREAKS DOWN
THROUGH THE SHORT TERM AS A SERIES OF STRONG SHORT WAVES DROP
ACROSS NEW ENGLAND AND THE GREAT LAKES REGION. THE SURFACE PICTURE
IS A LITTLE MUDDLED DUE TO A WEAK PRESSURE PATTERN AND A
DIVERGENCE OF MODEL SOLUTIONS. HOWEVER...A CONSENSUS OF GUIDANCE
HAS A FRONTAL SYSTEM DRAPED ACROSS THE DEEP SOUTH ON SUNDAY
LIFTING NORTH ON MONDAY INTO COASTAL GEORGIA AND SOUTH CAROLINA.
INCREASING MOISTURE ADVECTION WILL MAKE FOR A CLOUDY MONDAY WITH
POPS STEADILY INCREASING FROM SLIGHT CHANCE IN THE MORNING TO
LIKELY OVERNIGHT. SUNDAY HOWEVER LOOKS TO BE A DECENT DAY WITH
MINIMAL CHANCES OF PRECIP AND A GOOD BIT OF SUN...ESPECIALLY EARLY
ON. DAYTIME HEATING WILL LIKELY POP A CU FIELD IN THE
AFTERNOON...AND THE CIRRUS SHIELD WILL STEADILY INCREASE IN
ADVANCE OF MONDAYS FRONTAL SYSTEM. TEMPERATURES WILL BE QUITE
SEASONAL THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 3 PM SATURDAY...FORECAST MODELS FOR THE MEDIUM RANGE ARE IN
DECENT AGREEMENT ON THE SYSTEM MOVING ACROSS THE SOUTHEAST DURING
THE FIRST COUPLE OF DAYS. BOTH THE GFS AND ECMWF OPERATIONAL
MODELS SHOW A RATHER LETHARGIC SHORTWAVE THAT WAVERS BETWEEN AN
OPEN WAVE AND CLOSED LOW. I HAVE MAINTAINED THE GOOD CHANCE OF
SHOWERS FOR THE FIRST PART OF TUESDAY TRENDING DOWN THEREAFTER.
THE AFOREMENTIONED OPERATIONAL MODELS DIVERGE WITH REGARDS TO THE
MID LEVEL PATTERN FOR THE REMAINDER OF THE PERIOD. THE GFS KEEPS A
WEAKNESS AROUND THE AREA...MUCH LIKE WE HAVE SEEN THIS WEEK WHILE
THE ECMWF HAS A MORE PROGRESSIVE SOLUTION. WPC FAVORS MORE
BLENDING WITH ECMWF SOLUTIONS SO I HAVE BACKED OFF THE SLIGHT
CHANCE POPS LINGERING INTO WEDNESDAY AND THURSDAY. BEYOND THIS...A
STRONG SHORTWAVE MOVING THROUGH THE OHIO VALLEY AND ATTENDANT COLD
FRONT MOVE ACROSS LATE FRIDAY AND SATURDAY. AT THIS POINT THE
FRONT LOOKS TO BE MOISTURE STARVED AND INTRODUCED LOWER CHANCE
POPS FOR THE NEW DAY OF THE FORECAST PERIOD...SATURDAY.
REGARDING TEMPERATURES...I GENERALLY ADDED A DEGREE OR TWO ACROSS
THE BOARD TO WPC GUIDANCE AS THE WESTERLY FLOW THAT IS FORECAST TO
DEVELOP SHOULD ALLOW A DOWNSLOPE COMPONENT TO WARRANT. HOWEVER
MOST VALUES ARE WITHIN A FEW DEGREES OF CLIMATOLOGY.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...LINGERING MVFR CIGS AT KCRE/KMYR OVER THE NEXT FEW
HOURS...AND POSSIBLY AGAIN ALONG THE COAST JUST BEFORE DAYBREAK.
OTHERWISE EXPECT VFR AS HIGH PRESSURE CONTINUES TO BUILD ACROSS THE
AREA WITH A WEAKENING COASTAL TROUGH OFFSHORE.
LATEST RADAR DEPICTS LIGHT SHOWERS OFFSHORE BUT AS THEY CONTINUE TO
MOVE TOWARDS THE COAST...THEY CONTINUE TO WEAKEN AND ESSENTIALLY
DISSIPATE. LATEST OBS INDICATE VFR PREVAILS ACROSS THE AREA THIS
EVENING WITH THE EXCEPTION OF MVFR DUE TO LOW CIGS AT KMYR.
ANTICIPATE POSSIBILITY OF MVFR DUE TO LOW CIGS TO LINGER OVER THE
NEXT FEW HOURS AT KCRE/KMYR...AND THE POSSIBLY RE-OCCUR BEFORE
DAYBREAK ALONG THE COAST. OTHERWISE EXPECT VFR THROUGH THE OVERNIGHT
HOURS WITH NORTHEAST WINDS 5 TO 10 KTS. ON SUNDAY...ANY MVFR DUE TO
LOW CIGS COULD LINGER INTO THE LATE MORNING HOURS...BUT CONDITIONS
WILL GRADUALLY IMPROVE TO VFR WITH PERSISTENT NORTHEAST WINDS.
EXTENDED OUTLOOK...CHANCE OF SHOWERS/MVFR MONDAY AND TUESDAY AS LOW
PRESSURE MOVES ACROSS THE SOUTHEAST. MVFR/IFR CIGS ON WEDNESDAY/
POSSIBLY THURSDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 730 PM SATURDAY...SCA WILL BE LOWERED TO SCEC FOR THE ILM NC
WATERS...AND A SCEC WILL REMAIN IN EFFECT FOR THE ILM SC WATERS.
THE SCEC FOR ALL WATERS WILL REMAIN IN EFFECT THRU MIDDAY SUNDAY.
MODESTLY TIGHTENED SFC PG ACROSS THE WATERS WILL PRODUCE NE 15 TO
OCCASIONALLY 20 KT OF WINDS OVERNIGHT. SIGNIFICANT SEAS WILL RUN 3
TO 5 FT...EXCEPT 2 TO 4 FT SOUTH OF CAPE FEAR TO LITTLE RIVER
INLET. DOMINANT PERIODS WILL RUN 5 TO 6 SECONDS. NOT MUCH OF ANY
GROUND SWELL TO SPEAK OF.
PREVIOUS DISCUSSION..............................................
AS OF 3 PM SATURDAY...HIGH PRESSURE WEDGING DOWN THE COAST AND A
COASTAL TROUGH POSITIONED ABOUT 50 MILES OFFSHORE...CONTINUE TO
KEEP THE COASTAL WATERS PINCHED IN BETWEEN. THIS IS CREATING GUSTY
NE WINDS OF 15-25 KTS...AND SEAS OF 3 TO 6 FT THIS AFTN. A SLOW
DECREASE IN WIND SPEEDS IS EXPECTED TONIGHT AS THE HIGH PRESSURE
PUSHES FURTHER SOUTH...WEAKENING THE GRADIENT...BUT SPEEDS OF
10-20 KTS WILL REMAIN INTO SUNDAY MORNING. HOWEVER...THE SLIGHTLY
LOWER SPEEDS WILL ALLOW WAVE HEIGHTS TO DROP TO BELOW 6 FT...AND
THE SCA SHOULD BE ABLE TO EXPIRE AT 8PM FOR THE NORTHERN WATERS.
THEREAFTER...A SCEC MAY BE NEEDED FOR THE MUCH OF THE REST OF THE
NEAR TERM AS SEAS ARE FORECAST TO REMAIN 3-5 FT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...NORTHEAST WINDS OF 10 TO 15 KTS ON SUNDAY
WILL DECREASE TO AROUND 10 KTS OR LESS ON MONDAY AS OVERALL
PRESSURE GRADIENT SLACKENS. SEAS OF AROUND 3 FT ON SUNDAY WILL
DECREASE TO AROUND 2 FT ON MONDAY.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 3 PM SATURDAY...A MODEST NORTHEASTERLY FLOW WILL GREET
MARINERS TUESDAY MORNING ALONG WITH WIDESPREAD RAINFALL. WIND
SPEEDS WILL BE LIGHT INITIALLY...LESS THAN TEN KNOTS. AS WE
PROGRESS INTO EARLY WEDNESDAY...THE FLOW WILL BACK TO MORE OF A
DUE NORTHERLY DIRECTION AND INCREASE TO 10-15 KNOTS AS THE LOW
PRESSURE SYSTEM PULLS AWAY SLOWLY. BY THE END OF THE PERIOD WINDS
ARE BACK TO A NORTHEAST DIRECTION AS HIGH PRESSURE BUILDS DOWN
FROM THE CANADIAN MARITIMES. SIGNIFICANT SEAS SHOULD BE ON THE LOW
SIDE CITING THE LACK OF STRONG WINDS AND CHANGES IN THE
FETCH...GENERALLY 1-3 TO 2-4 FEET.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...REK
NEAR TERM...DCH/JDW
SHORT TERM...REK
LONG TERM...SHK
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1245 AM CDT FRI SEP 26 2014
.UPDATE...
ISSUED AT 1245 AM CDT FRI SEP 26 2014
NO CHANGES THIS UPDATE. NOT SEEING ANY LOW CLOUD OR FOG DEVELOPMENT
IN IFR SAT PICS. LATEST HRRR RUNS NOT SUGGESTING ANY LOW CLOUDS OR
FOG. THINKING AS IN PREVIOUS DISCUSSION THAT THE SOUTHEAST FLOW WILL
CONTINUE TO MIX WITH THE DRY AIR ABOVE THE BOUNDARY LAYER. FORECAST
IS ON TRACK.
UPDATE ISSUED AT 926 PM CDT THU SEP 25 2014
SURFACE LOW PRESSURE IN MONTANA WILL MAINTAIN A SOUTHEAST FLOW OF
AIR ACROSS THE REGION TONIGHT. RELATIVELY MOIST AIR ACROSS THE
EAST REMAIN IN PLACE. WHILE SOME PATCHY GROUND FOG IN LOW LYING
AREAS REMAINS IN THE BACK OF MY MIND...THE HRRR DOES NOT DEVELOP
LOW CLOUDS OR FOG TONIGHT...SO THE STEADY SOUTHEAST WINDS MAY
KEEP THINGS MIXED. HELD THE FOG OUT FOR NOW. OTHERWISE FORECAST
LOOKS GOOD.
UPDATE ISSUED AT 630 PM CDT THU SEP 25 2014
AT 6 PM CDT SKIES WERE CLEAR ACROSS THE REGION. LOW LEVEL MOISTURE
GRADIENT IS APPARENT IN DEW POINT TEMPERATURE WITH LOWER 60S IN THE
JAMES RIVER VALLEY AND MID 40S WEST. WILL CONSIDER THE POSSIBILITY
OF PATCHY FOG JAMES RIVER VALLEY AGAIN TONIGHT AS THE EVENING
PROGRESSES. IF THERE IS IT WILL BE PRETTY PATCHY. THE FOGPLOT
SUGGESTS PATCHY FOG JAMESTOWN BUT FOR NOW WILL MONITOR. SURFACE
WINDS MAY BE UP A BIT FOR FOG.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 400 PM CDT THU SEP 25 2014
ANOTHER WARM DAY ON FRIDAY FOLLOWING THE RECORD BREAKING
TEMPERATURES OF THIS AFTERNOON HIGHLIGHTS THE SHORT TERM FORECAST.
HIGH TEMPERATURE RECORDS HAVE ALREADY BEEN BROKEN AT
BISMARCK...WILLISTON...DICKINSON AND MINOT AS OF 3 PM CDT.
PRELIMINARY RECORD EVENT REPORTS WILL BE SENT BY 4 PM CDT...WITH
UPDATES THIS EVENING. OVERALL FOR FRIDAY...THE LOW LEVEL THERMAL
RIDGE AXIS REMAINS RATHER UNCHANGED IN ORIENTATION AND A FEW
DEGREES CELSIUS COOLER COMPARED TO TODAY. THUS...EXPECT MANY
PLACES TO TOUCH 90S DEGREES AGAIN ON FRIDAY...FOLLOWING THE WARMER
EDGE OF THE 12 UTC SUITE WHICH HAS VERIFIED BEST WITH TEMPERATURES
TODAY. RECORDS HIGHS FOR FRIDAY MAY BE BROKEN.
LOCATION.........FORECAST HIGH.........RECORD
BISMARCK.............90................96 IN 1963
MINOT................90................91 IN 1963
WILLISTON............93................92 IN 1983
DICKINSON...........90................92 IN 1963
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 PM CDT THU SEP 25 2014
QUASI-ACTIVE FLOW THROUGH THE EXTENDED PERIOD.
QUIET WEATHER FRIDAY NIGHT AND SATURDAY WILL TRANSITION TO A MORE
ACTIVE PATTERN SATURDAY NIGHT INTO SUNDAY AS A FRONTAL BOUNDARY
MOVES SLOWLY SOUTHWARD INTO THE NORTHERN PLAINS...AND AS LEAD
S/WV ENERGY FROM A DESERT SOUTHWEST UPPER LOW EJECTS INTO OUR
LOCAL AREA. COOLER TEMPERATURES WILL ALSO FILTER SOUTH ALONG TO
BEHIND THE FRONT.
PERHAPS ANOTHER QUIET PERIOD MONDAY AND/OR MONDAY NIGHT BEFORE THE
DESERT SOUTHWEST LOW LIFTS NORTH ACROSS THE DAKOTAS BRINGING VERY
GOOD PRECIPITATION CHANCES TO THE REGION FOR THE REMAINDER OF THE
LONG TERM PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1245 AM CDT FRI SEP 26 2014
SURFACE LOW PRESSURE ACROSS MONTANA WILL CONTINUE TO KEEP THE
DOWNSTREAM AREAS OF THE DAKOTAS IN A MILD SOUTHERLY WIND FLOW
TONIGHT AND FRIDAY. VFR IS FORECAST. SOME LOW LEVEL MOISTURE MAY
MAKE ITS WAY UP IN TO THE JAMES RIVER VALLEY EARLY THIS MORNING.
THINK THERE MAY BE SOME SCT CLOUDS AROUND 1 THOUSAND AGL FOR A BRIEF
PERIOD BEFORE SUNRISE. WINDS BETWEEN 500 AND 1000 AGL WILL INCREASE
TO 40 KTS NORTHWEST NORTH DAKOTA AFTER 07Z SO KEPT MENTION OF WIND
SHEAR AT KISN. RAISED WINDS A BIT AT KMOT/KBIS/KJMS THIS AFTERNOON
WITH STRONG SOUTHERLY WINDS ABOVE THE SURFACE THIS AFTERNOON IN
CENTRAL NORTH DAKOTA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...AYD
LONG TERM...NH
AVIATION...JV
AREA FORECAST DISCUSSION
NWS PENDLETON OR
230 PM PDT FRI SEP 26 2014
.SHORT TERM...TONIGHT THROUGH MONDAY...A LARGE UPPER LEVEL TROUGH
HAS MOVED OVER THE PACIFIC NORTHWEST TODAY. A SPLIT FLOW IS
DEVELOPING IN THE TROUGH WITH A CLOSED LOW FORMING IN THE BASE OF
THE TROUGH IN NORTHERN CALIFORNIA AND ANOTHER LOW OVER THE CANADIAN
ROCKIES. THIS IS LEADING TO A WEST TO SOUTHWEST FLOW OVER THE AREA.
THE WESTERLY FLOW BROUGHT SHOWERS TO THE WASHINGTON CASCADE CREST
TODAY AND THAT SHOULD CONTINUE THIS EVENING THOUGH THE INTENSITY IS
LESSENING. ELSEWHERE SHOWERS HAVE BEEN SLOW TO DEVELOP AND HAVE CUT
BACK ON THE POPS FOR TONIGHT, LIMITING IT TO A SLIGHT CHANCE AND
REMOVING THEM FROM A FEW PLACES, MAINLY THE BLUE MOUNTAIN FOOTHILLS.
THE HRRR MODEL SHOWS A BAND OF SHOWERS DEVELOPING AFTER MIDNIGHT IN
SOUTHEAST OREGON AND PROGRESSING TO THE SOUTHERN EDGE OF OUR AREA SO
HAVE LEFT A SLIGHT CHANCE OF SHOWERS IN NORTHEAST OREGON WHILE THE
REST OF THE AREA DRIES OUT. ON SATURDAY THE SOUTHERN LOW WILL COME
ASHORE AND WILL BE CENTERED NEAR RENO IN THE AFTERNOON. IT WILL THEN
MOVE INTO CENTRAL NEVADA ON SUNDAY AND INTO UTAH AND WEAKEN BY
MONDAY. CIRCULATION AROUND THE LOW WILL BRING A NORTH TO NORTHEAST
WRAP AROUND FLOW INTO OUR AREA SATURDAY AND SUNDAY. THIS WILL LEAD
TO A SLIGHT CHANCE OF SHOWERS IN THE EASTERN OREGON MOUNTAINS MAINLY
IN THE AFTERNOON AND EVENING ON SATURDAY AND SUNDAY. BY MONDAY THE
FLOW WILL HAVE TURNED BACK TO WESTERLY AND ANOTHER SYSTEM WILL BE
APPROACHING THE COAST IN THE AFTERNOON WITH A SLIGHT CHANCE OF
SHOWERS DEVELOPING ALONG THE WASHINGTON CASCADE CREST WHILE A FEW
LINGERING SHOWERS WILL REMAIN OVER THE EASTERN OREGON MOUNTAINS.
TEMPERATURES WILL BE IN THE UPPER 60S TO MID 70S WITH 60S IN THE
MOUNTAINS WHILE LOWS WILL BE IN THE MID 40S TO MID 50S WITH MID 30S
TO MID 40S IN THE MOUNTAINS. PERRY
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY. A DISTURBANCE IS EXPECTED
TO PASS ACROSS THE REGION MONDAY NIGHT AND A FEW SHOWERS ARE
POSSIBLE ACROSS THE AREA MOUNTAINS. OTHERWISE A RETURN TO DRIER
CONDITIONS IS LIKELY TUESDAY AND WEDNESDAY AS A RIDGE OF HIGH
PRESSURE DRIFTS THROUGH THE AREA. ANOTHER WEAK DISTURBANCE IS
POSSIBLE THURSDAY THAT COULD INCREASE MID AND HIGH LEVEL CLOUDS
MAINLY ACROSS THE NORTHERN PARTS OF THE REGION ALONG WITH A FEW
SHOWERS ALONG THE EAST SLOPES OF THE WA CASCADES. BY FRIDAY A
STRONGER RIDGE OF HIGH PRESSURE IS EXPECTED WITH A SLIGHT WARMING
TREND EXPECTED TOWARD THE END OF THE WEEK.
&&
.AVIATION...MAINLY VFR CONDITIONS WILL PERSIST ACROSS THE AREA.
HOWEVER LCL MVFR CEILINGS...THAT MAY DIP TO 5000 FEET COULD OCCUR IN
AND NEAR SHOWERS UNTIL 18Z SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 50 73 52 72 / 10 10 10 10
ALW 54 74 55 74 / 10 10 10 10
PSC 52 77 53 76 / 10 0 10 10
YKM 48 73 51 75 / 10 10 0 0
HRI 50 75 50 75 / 10 10 10 10
ELN 48 74 49 76 / 10 10 0 0
RDM 39 66 39 67 / 20 10 10 10
LGD 47 66 45 68 / 20 10 20 20
GCD 43 64 44 68 / 20 10 20 20
DLS 54 76 53 78 / 10 10 10 10
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
83/97/97
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1045 PM EDT SAT SEP 27 2014
.SYNOPSIS...
COOL HIGH PRESSURE WILL PERSIST ACROSS THE REGION TONIGHT AND WEAKEN
ON SUNDAY. A LOW PRESSURE SYSTEM WILL MOVE NORTHWARD FROM THE GULF
OF MEXICO SUNDAY NIGHT AND MONDAY AND SPREAD RAIN ACROSS THE REGION.
THE LOW SHOULD MOVE SLOWLY AWAY TO THE NORTHEAST MONDAY NIGHT AND
TUESDAY WITH COOL HIGH PRESSURE BUILDING IN FROM THE NORTHEAST ON
WEDNESDAY. A COLD FRONT WILL ARRIVE FROM THE NORTHWEST LATE IN THE
WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 1030 PM EDT SATURDAY...LATEST GUIDANCE SEEMS TO AGREE WELL
WITH OBSERVED TEMPERATURE TRENDS ACROSS THE NORTHWEST NC PIEDMONT
AND NORTHERN NC MOUNTAINS WHERE CLEAR SKIES HAVE ALLOWED FOR BETTER
RADIATIONAL COOLING. THUS...TWEAKED MINIMUM TEMPERATURES ACROSS THE
REGION BY BLENDING IN LATEST ADJMAV WHICH YIELDED SLIGHTLY LOWER
MINS THROUGH THE ABOVE MENTIONED ZONES. THIS MODIFICATION ALSO
REINFORCED WARMER TEMPERATURES ACROSS THE REMAINDER OF THE REGION
WHERE COOLING HAS BEEN STUNTED SOMEWHAT. FORECAST REMAINS ON TRACK
REGARDING INCREASING CLOUDINESS FROM THE SOUTHEAST OVERNIGHT AS
MOIST UPGLIDE REGIME ENHANCES. LASTLY...ALSO BLENDED IN LATEST HPC
QPF GUIDANCE THROUGH 00Z TUESDAY TO UPDATE CURRENT STORM TOTAL
PRECIPIATION AMOUNTS. HOWEVER THIS ACTION DID NOT LEND ITSELF TO
ANY SIGNIFICANT CHANGES.
PREVIOUS DISCUSSION...
AS OF 220 PM...DRY AIR CONTINUES TO MIX IN FROM THE NE ALIGNED IN A
PERSISTENT SFC WEDGE. THE MAJORITY OF HIGHER MOISTURE AND CLOUD
COVER HAS PUSHED OUT OF THE CWFA WITH LINGER BKN/OVC CONDS ACROSS
THE SW/RN ZONES. TEMPS WILL CONTINUE TO RISE A FEW MORE DEGREES
THROUGH MAX HEATING...REMAINING A CAT OR SO BELOW NORMAL.
A QUIET OVERNIGHT PERIOD IS IN STORE WITH A SUBTROPICAL HIGH
REMAINING OVER THE SE CONUS. RAP SOUNDINGS ARE SHOWING A DECOUPLED
ATMOS OVERNIGHT...ALLOWING MINS TO REACH NORMAL LEVELS NORTH AND A
COUPLE DEGREES ABOVE NORMAL SOUTH WITH LINGERING CLOUDS. THERE COULD
BE SOME MTN VALLEY FG DEVELOPING ARND SUNRISE...BUT TDDS WILL REMAIN
FAIRLY HIGH FOR MUCH OF A DENSE THREAT.
LOW TO MID LEVEL ATL MOISTURE BEGINS PUSHING IN EARLY SUN MORNING
AND THE SRN ZONES WILL SEE THE BEST CLOUD COVER AFT DAYBREAK. THE
NAM IS MORE AGGRESSIVE WITH THIS SCENARIO THAN THE GFS...WHICH KEEPS
THE DEEPER MOISTURE ALIGNED ALONG THE WEDGE BNDRY. SRN FA SOUNDINGS
SHOW NEARLY SATURATED COLUMNS BY THE AFTERNOON AS A WEAK COASTAL LOW
BEGINS ADVECTING GOM MOISTURE INTO THE REGION. STILL...THE MAIN FLOW
WILL BE ATL...WHICH WILL INSTIGATE GOOD MECH LIFT ACROSS THE SRN
ESCARPMENT...NE GA AND SW NC MTNS BY THE AFTERNOON. POPS WILL RISE
QUICKLY INTO THE HIGH CHANCE AND LOW/END LIKELY RANGE SUN AFTERNOON
ACROSS THE FAR WEST...HOWEVER PRECIP AMOUNTS WILL REMAIN FAIRLY LOW
THROUGH THE NRT PERIOD AS INSTABILITY REMAINS LOW KEEPING CONVEC
PRECIP WELL SOUTH. POPS WILL REMAIN NIL OUTSIDE THE MTNS AND SW/RN
ZONES. MAX TEMPS WILL FEATURE A SW/NE COOL/WARM GRADIENT DUE TO
CLOUD COVER AND DIFF HEATING.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 245 PM SATURDAY...AN H5 SHORTWAVE WILL LIFT FROM THE GULF
COAST TO THE EXTREME SRN APPALACHIANS SUNDAY NIGHT AND MERGE WITH A
NRN STREAM SHORTWAVE SWINGING EAST THROUGH THE OH VALLEY. AT LOWER
LEVELS...AN INCREASINGLY MOIST SOUTHEAST UPSLOPE FLOW WILL SET UP
OVER THE FORECAST AREA SUNDAY NIGHT TO ALLOW PRECIPITATION TO BECOME
WIDESPREAD BY DAYBREAK MONDAY...ACROSS AT LEAST THE SW HALF OF THE
AREA. DEEP LAYER FORCING WILL THEN CROSS THE REGION MON WITH THE
MERGING UPPER WAVES AND PASSING UPPER LEVEL JET DIVERGENCE. AN 850
MB LOW CENTER WILL LIKELY RIDE NE THROUGH THE SOUTHEAST PART OF THE
FORECAST AREA...SETTING UP ADDITIONAL WEAK FRONTOGENESIS OVER THE
AREA. THESE FEATURES WILL BE VERY SLOW TO MOVE E OR NE TO THE COAST
MON NIGHT THROUGH TUE...WITH CONTINUED LIGHT PRECIPITATION WRAPPING
BACK OVER THE REGION ON THE W SIDE OF THE LOW.
THE MAIN LIMITING FACTORS FOR HEAVY QPF ARE A FAIRLY DRY BOUNDARY
LAYER IN THE NC PIEDMONT AT ONSET...AS WELL AS THE STRONG POTENTIAL
FOR GULF COASTAL CONVECTION AND CONVECTION NEAR A WEAK WEDGE
BOUNDARY IMPEDING THE INFLUX OF MOISTURE. SO..THE QUESTION IS NOT
WHETHER IT WILL RAIN...BUT HOW MUCH. THE 12Z GFS IS PRODUCING A
BULLSEYE OF NEARLY 6 INCHES ALONG THE INTERSTATE 85 CORRIDOR...BUT
IT FEATURES LITTLE TO NO GULF COASTAL CONVECTION. THIS SOLUTION
SEEMS UNLIKELY...AND THE FORECAST WILL CONTINUE TO LEAN HEAVILY ON A
MODEL BLEND WITH A HEAVY NOD TOWARD THE DRIER SREF MEAN AND LATEST
ECM QPF. IN ADDITION...WITH A WEAK SURFACE CAD LAYER PERSISTING OR
REDEVELOPING AS THE RAIN ARRIVES...INSTABILITY SHOULD BE LARGELY
SHUNTED SOUTH OF THE REGION FOR THE UPCOMING EVENT. WITH 850 TO 500
MB LAPSE RATES RATHER WEAK OVER THE SFC HIGH...RAINFALL RATES SHOULD
NOT BE HIGH ENOUGH TO SUPPORT FLASH FLOODING. DURATION RAINFALL
ALONG MAIN STEMS AND THE MOST FLOOD PRONE AREAS WILL NEED TO BE
MONITORED...BUT ANTECEDENT CONDITIONS ARE UNFAVORABLE FOR MUCH OF A
HYDRO THREAT GIVEN EXPECTED QPF/DURATION. STILL...AN HWO MENTION
SEEMS WARRANTED FOR AT LEAST THE HEAVY RAINFALL MONDAY. A SMALLER
THAN MOS DIURNAL RANGE ON TEMPS WILL BE FEATURED WITH CAD CONDITIONS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM EDT SAT...A WEAK UPPER RIDGING WILL BUILD IN FROM THE
WEST TUE NIGHT INTO WED AS A DEAMPLIFYING SHORTWAVE PUSHES OFF THE
ATLANTIC COAST. THE UPPER RIDGE AXIS SHOULD CROSS THE REGION
THU...WITH SWLY FLOW ALOFT SETTING UP BY FRI IN LIGHT OF A DEEP
UPPER TROUGH APPROACHING FROM THE CENTRAL CONUS. THIS TROUGH IS
EXPECTED TO MOVE ACROSS THE EASTERN STATES LATE SAT INTO SUN.
AT THE SURFACE...A SURFACE WEDGE WILL SET UP ACROSS THE REGION BY
TUE NIGHT AND PERSIST THROUGH THU...YIELDING CONSIDERABLE LLVL
CLOUDINESS AND COOL NE WINDS DURING THIS PERIOD. NE WINDS SHOULD
VEER TO THE SE BY THU NIGHT AS THE SURFACE RIDGE WEAKENS AND SHIFT
EAST WHILE AN ACTIVE COLD FRONT APPROACHES FROM THE MISSISSIPPI
VALLEY. BOTH THE NEW 12Z GFS/ECMWF AGREE THAT THE FRONT WILL REACH
THE SOUTHERN APPALACHIANS BY AROUND SAT 00Z AND OFF TO OUR EAST BY
AROUND 12Z SAT. THE THREAT FOR SEVERE WEATHER LOOKS MINIMAL GIVEN
THE LATE OF GOOD UPPER FORCING/BOUNCY. IN FACT...MODELS HAVE TRENDED
A BIT DRIER AS THE FRONT WEAKENS AS IT CROSS THE FORECAST AREA.
HENCE...HAVE INHERITED LOW END CHANCE POPS DURING THE FROPA.
CONDITIONS SHOULD DRY OUT BY SAT AFTERNOON AS THE FRONT PUSHES
OFFSHORE AND A COOL DRY HIGH PRESSURE BUILDS IN FROM THE NW.
TEMPERATURES WILL REMAIN 3-7 DEGREES BELOW NORMAL THROUGHOUT THE
MEDIUM RANGE PERIOD.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE ENTIRE TAF CYCLE
AS HIGH PRESSURE WEDGE DOMINATES THE PATTERN. INITIALIZED TAF WITH
LIGHT NE FLOW UNDER SCT LOW VFR AND BKN HIGH LEVEL CIGS. THIS
CARRIES THROUGH THE OVERNIGHT BEFORE ATLANTIC MOISTURE ADVECTION
SPREADS BKN LOW VFR CIGS...AND OVC MID LEVEL CIGS ACROSS THE REGION
THROUGH THE REMAINDER OF THE PERIOD. NE FLOW WILL CONTINUE ON
SUNDAY IN THE 5-8KTS RANGE WITH SOME VEERING TOWARDS THE EAST
SOUTHEAST POSSIBLE LATE IN THE DAY.
ELSEWHERE...VFR CONDITIONS WILL PREVAIL ASIDE FOR POSSIBLE MVFR
LEVEL CIGS/VISB AT KAVL...AND MVFR CIGS AT ALL SC SITES BY MORNING.
OTHERWISE INITIALIZED ALL TAFS WITH BKN LOW VFR CIGS ASIDE FOR KHKY
WHERE FURTHER PROXIMITY TO MOISTURE AXIS YIELDS ONLY A FEW HIGH
LEVEL CIRRUS. INCREASING MOIST UPGLIDE FROM THE EAST WILL PROMOTE
ABOVE MENTIONED ENHANCED MVFR CLOUDINESS BY MID MORNING ACROSS SC
AND WESTERN NC...BEFORE POST SUNRISE MIXING ALLOWS FOR SLIGHT
IMPROVEMENT TO LOW VFR LEVELS THROUGH THE PERIOD. WINDS WILL REMAIN
NORTHEASTERLY AT ALL SITES ASIDE FOR KAVL WHERE CHANNELING PROMOTES
VEERED SOUTHEASTERLY FLOW BY LATE MORNING.
OUTLOOK...HIGH LEVELS OF MOISTURE WILL RETURN FOR THE START OF THE
WORK WEEK ASSOCIATED WITH AN AREA OF UNSETTLE WEATHER MOVING NORTH
OUT OF THE GULF OF MEXICO. PERIODS OF CONTINUOUS MODERATE TO HEAVY
RAINFALL WILL AFFECT THE AREA MON/TUE PRODUCING CIG AND VSBY
RESTRICTIONS.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT HIGH 100% HIGH 100% HIGH 91% MED 75%
KGSP HIGH 100% MED 74% HIGH 91% MED 75%
KAVL MED 66% MED 65% MED 77% MED 75%
KHKY HIGH 100% HIGH 100% MED 75% MED 75%
KGMU HIGH 100% MED 74% HIGH 91% MED 75%
KAND HIGH 92% MED 60% HIGH 91% MED 75%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...CDG/SBK
SHORT TERM...HG
LONG TERM...JOH
AVIATION...CDG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
740 PM EDT SAT SEP 27 2014
.SYNOPSIS...
COOL HIGH PRESSURE WILL PERSIST ACROSS THE REGION TONIGHT AND WEAKEN
ON SUNDAY. A LOW PRESSURE SYSTEM WILL MOVE NORTHWARD FROM THE GULF
OF MEXICO SUNDAY NIGHT AND MONDAY AND SPREAD RAIN ACROSS THE REGION.
THE LOW SHOULD MOVE SLOWLY AWAY TO THE NORTHEAST MONDAY NIGHT AND
TUESDAY WITH COOL HIGH PRESSURE BUILDING IN FROM THE NORTHEAST ON
WEDNESDAY. A COLD FRONT WILL ARRIVE FROM THE NORTHWEST LATE IN THE
WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 730 PM EDT SATURDAY...CURRENT FORECAST REMAINS ON TRACK
THEREFORE NO SIGNIFICANT CHANGES MADE/NEEDED WITH THIS UPDATE. DID
MAKE ADJUSTMENTS TO SKY COVER TO ACCOUNT FOR CURRENT LOW LEVEL
STRATUS ACROSS NORTHEAST GA AND THE WESTERN UPSTATE...AND ALSO TO
REINFORCE BUILDING STRATUS BY MORNING FOR MUCH OF THE REGION PER
LATEST GUIDANCE. ALSO TWEAKED TEMPERATURES AND DEWPOINTS TO REFLECT
LATEST OBSERVATIONS WHICH FEATURE TEMPERATURES HOVERING IN THE LOWER
TO MID 70S WITH THE COOLEST TEMPERATURES BEING ACROSS NORTHWEST NC
WHERE DRIER AIR HAS ALLOWED FOR A HEAD START ON RADIATIONAL COOLING
DUE TO LACK OF SKY COVER.
PREVIOUS DISCUSSION...
AS OF 220 PM...DRY AIR CONTINUES TO MIX IN FROM THE NE ALIGNED IN A
PERSISTENT SFC WEDGE. THE MAJORITY OF HIGHER MOISTURE AND CLOUD
COVER HAS PUSHED OUT OF THE CWFA WITH LINGER BKN/OVC CONDS ACROSS
THE SW/RN ZONES. TEMPS WILL CONTINUE TO RISE A FEW MORE DEGREES
THROUGH MAX HEATING...REMAINING A CAT OR SO BELOW NORMAL.
A QUIET OVERNIGHT PERIOD IS IN STORE WITH A SUBTROPICAL HIGH
REMAINING OVER THE SE CONUS. RAP SOUNDINGS ARE SHOWING A DECOUPLED
ATMOS OVERNIGHT...ALLOWING MINS TO REACH NORMAL LEVELS NORTH AND A
COUPLE DEGREES ABOVE NORMAL SOUTH WITH LINGERING CLOUDS. THERE COULD
BE SOME MTN VALLEY FG DEVELOPING ARND SUNRISE...BUT TDDS WILL REMAIN
FAIRLY HIGH FOR MUCH OF A DENSE THREAT.
LOW TO MID LEVEL ATL MOISTURE BEGINS PUSHING IN EARLY SUN MORNING
AND THE SRN ZONES WILL SEE THE BEST CLOUD COVER AFT DAYBREAK. THE
NAM IS MORE AGGRESSIVE WITH THIS SCENARIO THAN THE GFS...WHICH KEEPS
THE DEEPER MOISTURE ALIGNED ALONG THE WEDGE BNDRY. SRN FA SOUNDINGS
SHOW NEARLY SATURATED COLUMNS BY THE AFTERNOON AS A WEAK COASTAL LOW
BEGINS ADVECTING GOM MOISTURE INTO THE REGION. STILL...THE MAIN FLOW
WILL BE ATL...WHICH WILL INSTIGATE GOOD MECH LIFT ACROSS THE SRN
ESCARPMENT...NE GA AND SW NC MTNS BY THE AFTERNOON. POPS WILL RISE
QUICKLY INTO THE HIGH CHANCE AND LOW/END LIKELY RANGE SUN AFTERNOON
ACROSS THE FAR WEST...HOWEVER PRECIP AMOUNTS WILL REMAIN FAIRLY LOW
THROUGH THE NRT PERIOD AS INSTABILITY REMAINS LOW KEEPING CONVEC
PRECIP WELL SOUTH. POPS WILL REMAIN NIL OUTSIDE THE MTNS AND SW/RN
ZONES. MAX TEMPS WILL FEATURE A SW/NE COOL/WARM GRADIENT DUE TO
CLOUD COVER AND DIFF HEATING.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 245 PM SATURDAY...AN H5 SHORTWAVE WILL LIFT FROM THE GULF
COAST TO THE EXTREME SRN APPALACHIANS SUNDAY NIGHT AND MERGE WITH A
NRN STREAM SHORTWAVE SWINGING EAST THROUGH THE OH VALLEY. AT LOWER
LEVELS...AN INCREASINGLY MOIST SOUTHEAST UPSLOPE FLOW WILL SET UP
OVER THE FORECAST AREA SUNDAY NIGHT TO ALLOW PRECIPITATION TO BECOME
WIDESPREAD BY DAYBREAK MONDAY...ACROSS AT LEAST THE SW HALF OF THE
AREA. DEEP LAYER FORCING WILL THEN CROSS THE REGION MON WITH THE
MERGING UPPER WAVES AND PASSING UPPER LEVEL JET DIVERGENCE. AN 850
MB LOW CENTER WILL LIKELY RIDE NE THROUGH THE SOUTHEAST PART OF THE
FORECAST AREA...SETTING UP ADDITIONAL WEAK FRONTOGENESIS OVER THE
AREA. THESE FEATURES WILL BE VERY SLOW TO MOVE E OR NE TO THE COAST
MON NIGHT THROUGH TUE...WITH CONTINUED LIGHT PRECIPITATION WRAPPING
BACK OVER THE REGION ON THE W SIDE OF THE LOW.
THE MAIN LIMITING FACTORS FOR HEAVY QPF ARE A FAIRLY DRY BOUNDARY
LAYER IN THE NC PIEDMONT AT ONSET...AS WELL AS THE STRONG POTENTIAL
FOR GULF COASTAL CONVECTION AND CONVECTION NEAR A WEAK WEDGE
BOUNDARY IMPEDING THE INFLUX OF MOISTURE. SO..THE QUESTION IS NOT
WHETHER IT WILL RAIN...BUT HOW MUCH. THE 12Z GFS IS PRODUCING A
BULLSEYE OF NEARLY 6 INCHES ALONG THE INTERSTATE 85 CORRIDOR...BUT
IT FEATURES LITTLE TO NO GULF COASTAL CONVECTION. THIS SOLUTION
SEEMS UNLIKELY...AND THE FORECAST WILL CONTINUE TO LEAN HEAVILY ON A
MODEL BLEND WITH A HEAVY NOD TOWARD THE DRIER SREF MEAN AND LATEST
ECM QPF. IN ADDITION...WITH A WEAK SURFACE CAD LAYER PERSISTING OR
REDEVELOPING AS THE RAIN ARRIVES...INSTABILITY SHOULD BE LARGELY
SHUNTED SOUTH OF THE REGION FOR THE UPCOMING EVENT. WITH 850 TO 500
MB LAPSE RATES RATHER WEAK OVER THE SFC HIGH...RAINFALL RATES SHOULD
NOT BE HIGH ENOUGH TO SUPPORT FLASH FLOODING. DURATION RAINFALL
ALONG MAIN STEMS AND THE MOST FLOOD PRONE AREAS WILL NEED TO BE
MONITORED...BUT ANTECEDENT CONDITIONS ARE UNFAVORABLE FOR MUCH OF A
HYDRO THREAT GIVEN EXPECTED QPF/DURATION. STILL...AN HWO MENTION
SEEMS WARRANTED FOR AT LEAST THE HEAVY RAINFALL MONDAY. A SMALLER
THAN MOS DIURNAL RANGE ON TEMPS WILL BE FEATURED WITH CAD CONDITIONS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM EDT SAT...A WEAK UPPER RIDGING WILL BUILD IN FROM THE
WEST TUE NIGHT INTO WED AS A DEAMPLIFYING SHORTWAVE PUSHES OFF THE
ATLANTIC COAST. THE UPPER RIDGE AXIS SHOULD CROSS THE REGION
THU...WITH SWLY FLOW ALOFT SETTING UP BY FRI IN LIGHT OF A DEEP
UPPER TROUGH APPROACHING FROM THE CENTRAL CONUS. THIS TROUGH IS
EXPECTED TO MOVE ACROSS THE EASTERN STATES LATE SAT INTO SUN.
AT THE SURFACE...A SURFACE WEDGE WILL SET UP ACROSS THE REGION BY
TUE NIGHT AND PERSIST THROUGH THU...YIELDING CONSIDERABLE LLVL
CLOUDINESS AND COOL NE WINDS DURING THIS PERIOD. NE WINDS SHOULD
VEER TO THE SE BY THU NIGHT AS THE SURFACE RIDGE WEAKENS AND SHIFT
EAST WHILE AN ACTIVE COLD FRONT APPROACHES FROM THE MISSISSIPPI
VALLEY. BOTH THE NEW 12Z GFS/ECMWF AGREE THAT THE FRONT WILL REACH
THE SOUTHERN APPALACHIANS BY AROUND SAT 00Z AND OFF TO OUR EAST BY
AROUND 12Z SAT. THE THREAT FOR SEVERE WEATHER LOOKS MINIMAL GIVEN
THE LATE OF GOOD UPPER FORCING/BOUNCY. IN FACT...MODELS HAVE TRENDED
A BIT DRIER AS THE FRONT WEAKENS AS IT CROSS THE FORECAST AREA.
HENCE...HAVE INHERITED LOW END CHANCE POPS DURING THE FROPA.
CONDITIONS SHOULD DRY OUT BY SAT AFTERNOON AS THE FRONT PUSHES
OFFSHORE AND A COOL DRY HIGH PRESSURE BUILDS IN FROM THE NW.
TEMPERATURES WILL REMAIN 3-7 DEGREES BELOW NORMAL THROUGHOUT THE
MEDIUM RANGE PERIOD.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE ENTIRE TAF CYCLE
AS HIGH PRESSURE WEDGE DOMINATES THE PATTERN. INITIALIZED TAF WITH
LIGHT NE FLOW UNDER SCT LOW VFR AND BKN HIGH LEVEL CIGS. THIS
CARRIES THROUGH THE OVERNIGHT BEFORE ATLANTIC MOISTURE ADVECTION
SPREADS BKN LOW VFR CIGS...AND OVC MID LEVEL CIGS ACROSS THE REGION
THROUGH THE REMAINDER OF THE PERIOD. NE FLOW WILL CONTINUE ON
SUNDAY IN THE 5-8KTS RANGE WITH SOME VEERING TOWARDS THE EAST
SOUTHEAST POSSIBLE LATE IN THE DAY.
ELSEWHERE...VFR CONDITIONS WILL PREVAIL ASIDE FOR POSSIBLE MVFR
LEVEL CIGS/VISB AT KAVL...AND MVFR CIGS AT ALL SC SITES BY MORNING.
OTHERWISE INITIALIZED ALL TAFS WITH BKN LOW VFR CIGS ASIDE FOR KHKY
WHERE FURTHER PROXIMITY TO MOISTURE AXIS YIELDS ONLY A FEW HIGH
LEVEL CIRRUS. INCREASING MOIST UPGLIDE FROM THE EAST WILL PROMOTE
ABOVE MENTIONED ENHANCED MVFR CLOUDINESS BY MID MORNING ACROSS SC
AND WESTERN NC...BEFORE POST SUNRISE MIXING ALLOWS FOR SLIGHT
IMPROVEMENT TO LOW VFR LEVELS THROUGH THE PERIOD. WINDS WILL REMAIN
NORTHEASTERLY AT ALL SITES ASIDE FOR KAVL WHERE CHANNELING PROMOTES
VEERED SOUTHEASTERLY FLOW BY LATE MORNING.
OUTLOOK...HIGH LEVELS OF MOISTURE WILL RETURN FOR THE START OF THE
WORK WEEK ASSOCIATED WITH AN AREA OF UNSETTLE WEATHER MOVING NORTH
OUT OF THE GULF OF MEXICO. PERIODS OF CONTINUOUS MODERATE TO HEAVY
RAINFALL WILL AFFECT THE AREA MON/TUE PRODUCING CIG AND VSBY
RESTRICTIONS.
CONFIDENCE TABLE...
23-05Z 05-11Z 11-17Z 17-23Z
KCLT HIGH 100% HIGH 100% HIGH 100% MED 79%
KGSP HIGH 100% HIGH 92% HIGH 81% MED 79%
KAVL HIGH 92% LOW 53% MED 78% MED 75%
KHKY HIGH 100% HIGH 100% HIGH 87% MED 75%
KGMU HIGH 100% HIGH 92% HIGH 81% MED 79%
KAND HIGH 100% MED 72% HIGH 82% MED 79%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...CDG/SBK
SHORT TERM...HG
LONG TERM...JOH
AVIATION...CDG
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
1001 PM CDT Sat Sep 27 2014
.DISCUSSION...
Area radars show earlier -SHRA has diminished across the region,
w/latest RUC showing an uneventful night ahead. Will do a quick
update to removed isolated convection first period, and adjust
other parameters as necessary. Updates out shortly.
&&
PREV DISCUSSION... /ISSUED 238 PM CDT Sat Sep 27 2014/
DISCUSSION...
Satellite imagery earlier this morning showed an eastward moving low
pressure center over Terrell County. Associated widely scattered
showers and thunderstorms are still lingering over the Permian
Basin. Expectations are that this activity will continue through
sunset before finally dissipating.
An upper level storm system located over central California will
make its way into the central Rockies by Monday. The approach of
this system with result in associated lee trough development from
eastern Co. into Far West Texas by Monday afternoon. This surface
trough will serve as the focus of isolated thunderstorm development
over the western third of the County Warning Area on Monday and over
portions of the Permian Basin Tuesday and Wednesday.
Model CAPE values near 1000 J/kg along with 0-6 km bulk shear values
around 30 are forecast Tuesday afternoon over the northern
portions of the Permian Basin and into the Rolling Plains. In
edition, the right entrance region of the 250 MB jet is over that
area as well. I thought that was enough to warrant a slight
increase in Tuesday afternoon thunderstorm chances over that area.
It is not inconceivable that we could see an isolated severe thunderstorm
in this general area on Tuesday.
As the upper storm system slides east, so goes the surface trough
and our rain chances. A cold front moving through the area Thursday
should be a dry one, with drier and cooler air moving into the area
behind it.
&&
.PRELIMINARY POINT TEMPS/POPS...
ANDREWS TX 59 79 62 83 / 0 10 10 10
BIG SPRING TX 60 82 64 85 / 0 10 10 10
CARLSBAD NM 61 81 60 85 / 0 10 10 20
DRYDEN TX 63 86 66 89 / 0 10 10 10
FORT STOCKTON TX 63 85 64 88 / 0 10 10 10
GUADALUPE PASS TX 57 76 59 80 / 10 10 20 20
HOBBS NM 59 78 60 80 / 0 10 10 10
MARFA TX 50 81 54 83 / 10 10 10 20
MIDLAND INTL AIRPORT TX 60 81 62 85 / 0 10 10 10
ODESSA TX 61 81 64 85 / 0 10 10 10
WINK TX 63 86 64 89 / 0 10 10 10
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
&&
$$
27/44
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AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1221 PM CDT FRI SEP 26 2014
.AVIATION...
/18Z TAFS/
An area of light to moderate rain showers continues to move
northwest across I-10 into the Permian Basin. Farther north, a few
cells have developed in the vicinity of KABI. Additional
convective development is anticipated this afternoon, especially
south of KABI. Showers were added (as a VCSH) at the forecast
terminals (excluding KABI) this afternoon with a tempo for thunder
at KJCT and KSOA. Prevailing VFR conditions are expected, but we
may see tempo MVFR conditions in an around convection. Showers
will likely linger into the overnight hours, but coverage is
expected to decrease. Patchy MVFR ceilings will be possible late
tonight along the I-10 corridor.
Johnson
&&
.PREV DISCUSSION... /ISSUED 629 AM CDT Fri Sep 26 2014/
AVIATION...
/12Z TAFS/
VFR conditions prevailing across most of West Central Texas early
this morning, but with a fairly widespread mixture of mid and
high clouds across the area. A few lower clouds have developed
underneath, patchy MVFR ceilings around 2k feet, but they are
having trouble becoming more widespread with all of the higher
clouds overhead. Ceilings should lower through the day across the
area, likely remaining in the low end VFR range, as showers and
thunderstorms become more widespread. Hard to pinpoint just when
and where they will develop, but models suggest they will be
fairly widespread near the southern terminals of KSOA, KJCT, and
KBBD (Sonora, Junction, and Brady) for a good portion of the
afternoon and evening hours.
PREV DISCUSSION... /ISSUED 411 AM CDT FRI SEP 26 2014/
SHORT TERM...
(Today and tonight)
Potent little upper level low is evident on water vapor imagery
across the Big Bend region early this morning. System will not be
moving fast, and will tend to wobble as shortwaves rotate around
it, but the general trend for the system to move slowly east.
The GFS for several days, and now the TTU WRF and the HRRR as
well, show the system finally tapping better low level moisture
out of the Gulf of Mexico to produce an expanding area of showers
and storms this afternoon and evening. Best chances look to be on
the east and northeast side of the low, so across the Trans Pecos
and Del Rio areas north into the Northern Edwards Plateau and
Northwest Hill Country. Have increased PoPs as far north as San
Angelo and Brownwood, but appears the best chances will be the
I-10 corridor from Ozona to Sonora to Junction.
Whatever does develop will likely linger into the evening hours.
And given the moisture and lift in place as the low itself treks
across the area, would not be surprised to see a few showers or
storms linger well into or even through the overnight hours.
LONG TERM...
/Saturday through Monday/
The upper level low(currently over the Big Bend) will open up into
a trough and move over east Texas by Saturday evening. However a
few showers and thunderstorms are possible Saturday due to the
slow movement of this system and some weak instability over the
southern half of the area. Looks like a dry forecast for the end
of the weekend into the first part of next week. A weak upper
level ridge will be over the Southern Plains. Temperatures will be
close to seasonable values. Highs will be in the lower to mid 80s
with lows in the 60s.
/Tuesday through next Friday/
A dry forecast is in store for the middle part of next week and
then a slight chance of rain next Thursday. A strong upper level
trough will settle into the western US early next week. The first
piece of energy(negative tilt shortwave) will lift out into the
central and northern Plains. This upper level system will miss
West Central Texas, however low level southerly flow will increase
across the area by mid week. The mean upper level trough axis will
remain across the western US and another piece of energy will drop
into the trough. this second shot of ascent will move out into the
Plains late next week. Also, a cold front will move east with the
upper level dynamics. There ECMWF is more amplified and further
south with the second system(affecting West Central Texas) then
the GFS model. For now, will go with a slight chance of
thunderstorms mainly Thursday across much of the area due to at
least weak convergence along the front and some instability.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 83 63 83 63 86 / 20 20 10 5 5
San Angelo 81 62 83 62 84 / 40 30 20 10 5
Junction 80 61 82 62 86 / 40 50 20 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
629 AM CDT Fri Sep 26 2014
.AVIATION...
/12Z TAFS/
VFR conditions prevailing across most of West Central Texas early
this morning, but with a fairly widespread mixture of mid and high
clouds across the area. A few lower clouds have developed
underneath, patchy MVFR ceilings around 2k feet, but they are
having trouble becoming more widespread with all of the higher
clouds overhead. Ceilings should lower through the day across the
area, likely remaining in the low end VFR range, as showers and
thunderstorms become more widespread. Hard to pinpoint just when
and where they will develop, but models suggest they will be
fairly widespread near the southern terminals of KSOA, KJCT, and
KBBD (Sonora, Junction, and Brady) for a good portion of the
afternoon and evening hours.
&&
.PREV DISCUSSION... /ISSUED 411 AM CDT FRI SEP 26 2014/
SHORT TERM...
(Today and tonight)
Potent little upper level low is evident on water vapor imagery
across the Big Bend region early this morning. System will not be
moving fast, and will tend to wobble as shortwaves rotate around it,
but the general trend for the system to move slowly east. The GFS
for several days, and now the TTU WRF and the HRRR as well, show the
system finally tapping better low level moisture out of the Gulf of
Mexico to produce an expanding area of showers and storms this
afternoon and evening. Best chances look to be on the east and
northeast side of the low, so across the Trans Pecos and Del Rio
areas north into the Northern Edwards Plateau and Northwest Hill
Country. Have increased PoPs as far north as San Angelo and
Brownwood, but appears the best chances will be the I-10 corridor
from Ozona to Sonora to Junction.
Whatever does develop will likely linger into the evening hours. And
given the moisture and lift in place as the low itself treks across
the area, would not be surprised to see a few showers or storms linger
well into or even through the overnight hours.
LONG TERM...
/Saturday through Monday/
The upper level low(currently over the Big Bend) will open up into a
trough and move over east Texas by Saturday evening. However a few
showers and thunderstorms are possible Saturday due to the slow
movement of this system and some weak instability over the southern
half of the area. Looks like a dry forecast for the end of the
weekend into the first part of next week. A weak upper level ridge
will be over the Southern Plains. Temperatures will be close to
seasonable values. Highs will be in the lower to mid 80s with lows
in the 60s.
/Tuesday through next Friday/
A dry forecast is in store for the middle part of next week and then
a slight chance of rain next Thursday. A strong upper level trough
will settle into the western US early next week. The first piece of
energy(negative tilt shortwave) will lift out into the central and
northern Plains. This upper level system will miss West Central
Texas, however low level southerly flow will increase across the
area by mid week. The mean upper level trough axis will remain
across the western US and another piece of energy will drop into the
trough. this second shot of ascent will move out into the Plains
late next week. Also, a cold front will move east with the upper
level dynamics. There ECMWF is more amplified and further south with
the second system(affecting West Central Texas) then the GFS model.
For now, will go with a slight chance of thunderstorms mainly
Thursday across much of the area due to at least weak convergence
along the front and some instability.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 83 63 83 63 85 / 20 20 10 5 5
San Angelo 81 62 83 63 84 / 30 30 20 10 5
Junction 80 61 82 62 85 / 50 50 20 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
625 AM CDT FRI SEP 26 2014
.DISCUSSION...
SEE THE 12Z AVIATION DISCUSSION BELOW.
40
&&
.AVIATION...
VFR SCATTERED TO BROKEN SKY COVER EXPECTED THROUGH THE PERIOD...
ALTHOUGH THERE IS AN OUTSIDE CHANCE FOR MVFR AT KGLS THROUGH EARLY
THIS AFTERNOON IF MORE THAN JUST ISOLATED SHOWERS DEVELOP OVER OR
NEAR THE SITE. WINDS ARE THE MAIN CONCERN. LIGHT NORTHEASTERLY
WINDS ARE EXPECTED TO BECOME EASTERLY LATER THIS MORNING...AND
THEN SOUTHEASTERLY THIS AFTERNOON AS HIGH PRESSURE BUILDS INTO
SOUTHEAST TEXAS.
40
&&
.PREV DISCUSSION... /ISSUED 414 AM CDT FRI SEP 26 2014/
DISCUSSION...
AT 3 AM...A WEAK TROUGH OF LOW PRESSURE OVER THE WESTERN GULF OF
MEXICO EXTENDED FROM ABOUT MATAGORDA BAY TO A WEAK AREA OF LOW
PRESSURE OVER THE SOUTHERN GULF. HIGH PRESSURE OVER THE CENTRAL
GREAT LAKES EXTENDED S-SW INTO TEXAS AND CONTINUES TO BRING
SLIGHTLY DRIER AIR INTO THE NE HALF OF SE TX. AT 850 MB...HIGH
PRESSURE WAS LOCATED OVER THE MID-MISSISSIPPI VALLEY WITH A WELL
DEFINED TROUGH OF LOW PRESSURE OVER THE CENTRAL ROCKIES. DEEP 850
MB MSTR WAS LOCATED OVER DEEP SOUTH TEXAS INTO NORTHERN MEXICO. AT
700 MB...SLIGHTLY DEEPER MSTR WAS LOCATED OVER SW LA AND OVER
NORTHERN MEXICO. AT 250 MB...A WELL DEFINED UPPER LEVEL TROUGH
EXTENDED FROM CENTRAL ILLINOIS SW TOWARD THE TEXAS PANHANDLE. A
FAIRLY STOUT JET WAS LOCATED ON THE EAST SIDE OF THE UPPER
TROUGH. MODELS DIFFER WITH REGARD TO THE JET DYNAMICS TODAY WITH
THE NAM BEING THE MOST AGGRESSIVE WITH A FAVORABLE JET POSITION
THAT FAVORS MORE WIDESPREAD RAINFALL. THE GFS/ECMWF ARE LESS
FAVORABLE WITH WEAKER JET DYNAMICS AND BETTER LIFT TO THE SOUTH.
FEEL THE ECMWF INITIALIZED BETTER THAN BOTH THE NAM AND GFS SO
FEEL IT`S SOLN HAS A BETTER HANDLE ON THE DYNAMICS.
FCST SOUNDINGS SHOW THE BEST MSTR OVER THE SW ZONES THIS MORNING
WITH SOME DRIER AIR FILTERING INTO THE AREA FROM THE NORTHEAST DURING
THE AFTN. PW VALUES AND THE BEST LIFT ASSOCIATED WITH THE SFC
TROUGH ALSO LOOKS TO BE THIS MORNING. OVERALL...LOOKS LIKE THE
BEST CHANCE OF RAIN WILL BE OVER THE SW ZONES THROUGH THE MORNING
AND THIS IS SUPPORTED BY THE HRRR AND ARW. LEANED TOWARD THE DRIER
SHORT TERM GUIDANCE. TRIMMED POPS AND PROBABLY WASN`T AGGRESSIVE
ENOUGH IN LOWERING RAIN CHANCES FOR TODAY.
PW VALUES ON SATURDAY ARE PROGGED TO INCREASE TO AROUND 1.60
INCHES. STILL LOOKS TOO DRY TO GET MUCH IN THE WAY OF RAINFALL.
DYNAMICS DON`T LOOK ALL THAT FAVORABLE SO WENT AGAIN WITH LOW
POPS WITH THE BEST CHANCE FOR RAIN OVER THE SOUTHWEST ZONES. THE
WEAKNESS OVER TEXAS PHASES WITH A STRONGER UPPER LEVEL FEATURE
OVER THE WESTERN GREAT LAKES ON SUNDAY. AN UPPER LEVEL RIDGE WILL
DEVELOP OVER TEXAS IN RESPONSE TO THE PHASING SYSTEM TO THE NORTH
AND A STRONG UPPER LEVEL LOW MOVING INTO THE PACIFIC NORTHWEST.
THE UPPER RIDGE WILL BRING WARMER AND DRIER CONDITIONS TO SE TX
FOR MOST OF NEXT WEEK. A DEEP UPPER LEVEL TROUGH OVER THE WESTERN
U.S. WILL APPROACH THE STATE ON FRIDAY. RAIN CHANCES SHOULD
INCREASE AGAIN AS THE UPPER TROUGH APPROACHES. GFS APPEARS TO BE
HAVING SOME RUN TO RUN CONTINUITY ISSUES SO LEANED TOWARD THE
ECMWF. THE ECMWF IS A BIT SLOWER AND LESS AGGRESSIVE WITH THE SFC
BOUNDARY AND SFC WINDS. 43
MARINE...
THE MAIN ISSUES WILL BE TIDE LEVELS AND WINDS.
TODAY THE HIGH TIDES WILL LIKELY REACH TO AROUND 3 FEET ABOVE THE
MEAN LOWER LOW WATER LEVEL AT BOTH FREEPORT AND THE GALVESTON BAY
ENTRANCE. THIS MAY LEAD TO MINOR FLOODING IN LOW-LYING AREAS. THIS
SCENARIO MAY REPEAT AGAIN ON SATURDAY. ALTHOUGH THE WIND DIRECTION
MAY BECOME LESS FAVORABLE...SWELLS MAY KEEP THE TIDE LEVELS SLIGHTLY
ELEVATED.
EASTERLY WINDS SHOULD BECOME NORTHEASTERLY NEAR THE COAST AND OVER
THE BAYS. HOWEVER...WIND SPEEDS WILL LIKELY REACH CAUTION LEVELS
TONIGHT BEFORE DIMINISHING ON SATURDAY.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 69 87 67 89 67 / 10 10 10 10 10
HOUSTON (IAH) 69 87 68 89 67 / 10 20 10 10 10
GALVESTON (GLS) 76 85 75 86 75 / 10 30 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
414 AM CDT FRI SEP 26 2014
.DISCUSSION...
AT 3 AM...A WEAK TROUGH OF LOW PRESSURE OVER THE WESTERN GULF OF
MEXICO EXTENDED FROM ABOUT MATAGORDA BAY TO A WEAK AREA OF LOW
PRESSURE OVER THE SOUTHERN GULF. HIGH PRESSURE OVER THE CENTRAL
GREAT LAKES EXTENDED S-SW INTO TEXAS AND CONTINUES TO BRING
SLIGHTLY DRIER AIR INTO THE NE HALF OF SE TX. AT 850 MB...HIGH
PRESSURE WAS LOCATED OVER THE MID-MISSISSIPPI VALLEY WITH A WELL
DEFINED TROUGH OF LOW PRESSURE OVER THE CENTRAL ROCKIES. DEEP 850
MB MSTR WAS LOCATED OVER DEEP SOUTH TEXAS INTO NORTHERN MEXICO. AT
700 MB...SLIGHTLY DEEPER MSTR WAS LOCATED OVER SW LA AND OVER
NORTHERN MEXICO. AT 250 MB...A WELL DEFINED UPPER LEVEL TROUGH
EXTENDED FROM CENTRAL ILLINOIS SW TOWARD THE TEXAS PANHANDLE. A
FAIRLY STOUT JET WAS LOCATED ON THE EAST SIDE OF THE UPPER
TROUGH. MODELS DIFFER WITH REGARD TO THE JET DYNAMICS TODAY WITH
THE NAM BEING THE MOST AGGRESSIVE WITH A FAVORABLE JET POSITION
THAT FAVORS MORE WIDESPREAD RAINFALL. THE GFS/ECMWF ARE LESS
FAVORABLE WITH WEAKER JET DYNAMICS AND BETTER LIFT TO THE SOUTH.
FEEL THE ECMWF INITIALIZED BETTER THAN BOTH THE NAM AND GFS SO
FEEL IT`S SOLN HAS A BETTER HANDLE ON THE DYNAMICS.
FCST SOUNDINGS SHOW THE BEST MSTR OVER THE SW ZONES THIS MORNING
WITH SOME DRIER AIR FILTERING INTO THE AREA FROM THE NORTHEAST DURING
THE AFTN. PW VALUES AND THE BEST LIFT ASSOCIATED WITH THE SFC
TROUGH ALSO LOOKS TO BE THIS MORNING. OVERALL...LOOKS LIKE THE
BEST CHANCE OF RAIN WILL BE OVER THE SW ZONES THROUGH THE MORNING
AND THIS IS SUPPORTED BY THE HRRR AND ARW. LEANED TOWARD THE DRIER
SHORT TERM GUIDANCE. TRIMMED POPS AND PROBABLY WASN`T AGGRESSIVE
ENOUGH IN LOWERING RAIN CHANCES FOR TODAY.
PW VALUES ON SATURDAY ARE PROGGED TO INCREASE TO AROUND 1.60
INCHES. STILL LOOKS TOO DRY TO GET MUCH IN THE WAY OF RAINFALL.
DYNAMICS DON`T LOOK ALL THAT FAVORABLE SO WENT AGAIN WITH LOW
POPS WITH THE BEST CHANCE FOR RAIN OVER THE SOUTHWEST ZONES. THE
WEAKNESS OVER TEXAS PHASES WITH A STRONGER UPPER LEVEL FEATURE
OVER THE WESTERN GREAT LAKES ON SUNDAY. AN UPPER LEVEL RIDGE WILL
DEVELOP OVER TEXAS IN RESPONSE TO THE PHASING SYSTEM TO THE NORTH
AND A STRONG UPPER LEVEL LOW MOVING INTO THE PACIFIC NORTHWEST.
THE UPPER RIDGE WILL BRING WARMER AND DRIER CONDITIONS TO SE TX
FOR MOST OF NEXT WEEK. A DEEP UPPER LEVEL TROUGH OVER THE WESTERN
U.S. WILL APPROACH THE STATE ON FRIDAY. RAIN CHANCES SHOULD
INCREASE AGAIN AS THE UPPER TROUGH APPROACHES. GFS APPEARS TO BE
HAVING SOME RUN TO RUN CONTINUITY ISSUES SO LEANED TOWARD THE
ECMWF. THE ECMWF IS A BIT SLOWER AND LESS AGGRESSIVE WITH THE SFC
BOUNDARY AND SFC WINDS. 43
&&
.MARINE...
THE MAIN ISSUES WILL BE TIDE LEVELS AND WINDS.
TODAY THE HIGH TIDES WILL LIKELY REACH TO AROUND 3 FEET ABOVE THE
MEAN LOWER LOW WATER LEVEL AT BOTH FREEPORT AND THE GALVESTON BAY
ENTRANCE. THIS MAY LEAD TO MINOR FLOODING IN LOW-LYING AREAS. THIS
SCENARIO MAY REPEAT AGAIN ON SATURDAY. ALTHOUGH THE WIND DIRECTION
MAY BECOME LESS FAVORABLE...SWELLS MAY KEEP THE TIDE LEVELS SLIGHTLY
ELEVATED.
EASTERLY WINDS SHOULD BECOME NORTHEASTERLY NEAR THE COAST AND OVER
THE BAYS. HOWEVER...WIND SPEEDS WILL LIKELY REACH CAUTION LEVELS
TONIGHT BEFORE DIMINISHING ON SATURDAY.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 86 69 87 67 89 / 20 10 10 10 10
HOUSTON (IAH) 86 69 87 68 89 / 20 10 20 10 10
GALVESTON (GLS) 84 76 85 75 86 / 30 10 30 20 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
411 AM CDT FRI SEP 26 2014
.SHORT TERM...
(Today and tonight)
Potent little upper level low is evident on water vapor imagery
across the Big Bend region early this morning. System will not be
moving fast, and will tend to wobble as shortwaves rotate around it,
but the general trend for the system to move slowly east. The GFS
for several days, and now the TTU WRF and the HRRR as well, show the
system finally tapping better low level moisture out of the Gulf of
Mexico to produce an expanding area of showers and storms this
afternoon and evening. Best chances look to be on the east and
northeast side of the low, so across the Trans Pecos and Del Rio
areas north into the Northern Edwards Plateau and Northwest Hill
Country. Have increased PoPs as far north as San Angelo and
Brownwood, but appears the best chances will be the I-10 corridor
from Ozona to Sonora to Junction.
Whatever does develop will likely linger into the evening hours. And
given the moisture and lift in place as the low itself treks across
the area, would not be surprised to see a few showers or storms linger
well into or even through the overnight hours.
.LONG TERM...
/Saturday through Monday/
The upper level low(currently over the Big Bend) will open up into a
trough and move over east Texas by Saturday evening. However a few
showers and thunderstorms are possible Saturday due to the slow
movement of this system and some weak instability over the southern
half of the area. Looks like a dry forecast for the end of the
weekend into the first part of next week. A weak upper level ridge
will be over the Southern Plains. Temperatures will be close to
seasonable values. Highs will be in the lower to mid 80s with lows
in the 60s.
/Tuesday through next Friday/
A dry forecast is in store for the middle part of next week and then
a slight chance of rain next Thursday. A strong upper level trough
will settle into the western US early next week. The first piece of
energy(negative tilt shortwave) will lift out into the central and
northern Plains. This upper level system will miss West Central
Texas, however low level southerly flow will increase across the
area by mid week. The mean upper level trough axis will remain
across the western US and another piece of energy will drop into the
trough. this second shot of ascent will move out into the Plains
late next week. Also, a cold front will move east with the upper
level dynamics. There ECMWF is more amplified and further south with
the second system(affecting West Central Texas) then the GFS model.
For now, will go with a slight chance of thunderstorms mainly
Thursday across much of the area due to at least weak convergence
along the front and some instability.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 83 63 83 63 85 / 20 20 10 5 5
San Angelo 81 62 83 63 84 / 30 30 20 10 5
Junction 80 61 82 62 85 / 50 50 20 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07/21
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1129 PM CDT THU SEP 25 2014
.UPDATE...
A FEW LIGHT SHOWERS CONTINUE TO PERSIST FROM EXTREME SOUTHEAST NEW
MEXICO...NEAR EUNICE...TO AROUND SEMINOLE. THIS ACTIVITY WAS
DRIFTING NORTHWARD AND COULD PERHAPS AFFECT THE
SOUTHWESTERN/WESTERN ZONES THROUGH LATE TONIGHT...THOUGH MOST
SPOTS WILL LIKE STAY DRY. STILL...WE DID MAINTAIN THE SLIGHT
CHANCE POPS ALREADY IN PLACE ACROSS THE WESTERN ZONES THROUGH 12Z
GIVEN THIS POSSIBILITY. ALSO OF CONCERN IS THE POTENTIAL FOR FOG
DEVELOPMENT LATER TONIGHT...PRIMARILY ON THE CAPROCK...WHERE
DEWPOINT DEPRESSIONS ARE ALREADY QUITE LOW. WINDS WILL BE
LIGHT...BUT WHETHER SKIES COMPLETELY CLEAR OUT REMAINS A QUESTION
MARK AND THE LIMITING FACTOR ON FOG DEVELOPMENT AND COVERAGE.
HOWEVER...THE LATEST NAM...HRRR AND RAP ALL INDICATE AT LEAST
PATCHY FOG DEVELOPMENT...POTENTIALLY DENSE...TOWARD DAWN ON THE
CAP. HENCE...WE HAVE GONE AHEAD AND INSERTED A PATCHY FOG MENTION
IN THE 9-15Z TIME-FRAME. NO OTHER CHANGES WERE MADE TO THE
FORECAST ATTM.
&&
.AVIATION...
GENERALLY VFR CONDITIONS ARE EXPECTED AT THE TERMINALS THIS TAF
PERIOD. A FEW LIGHT SHOWERS CONTINUE TO PERSIST WELL TO THE
SOUTHWEST OF KLBB...WHERE THEY WILL LIKELY REMAIN. EVEN IF A
SHOWER DOES MANAGE TO GET OVER KLBB /WHICH IS A LOW PROBABILITY/
VFR CONDITIONS WILL MOST LIKELY PERSIST. OF A GREATER CONCERN IS
THE PROSPECTS FOR FOG DEVELOPMENT EARLY FRIDAY MORNING...IF SKIES
CAN CLEAR. IT IS UNCERTAIN WHETHER CLOUDS WILL CLEAR SOON ENOUGH
FOR FOG TO DEVELOP AT KLBB...BUT THE LATEST SIGNALS ARE STRONGER
AND WE HAVE INCLUDED A TEMPO GROUP WITH MVFR VISIBILITIES. THERE
IS EVEN THE POTENTIAL FOR LOCALLY DENSE FOG AT KLBB...SO THIS WILL
HAVE TO BE MONITORED OVER THE COMING HOURS. FURTHER EAST AT
KCDS...WARMER AND DRY AIR SHOULD KEEP THE RISK OF FOG AT
BAY...WITH VFR CONDITIONS THROUGHOUT. ANY FOG AT KLBB SHOULD
QUICKLY THIN SHORTLY AFTER SUNRISE. FINALLY...ISOLATED CONVECTION
WILL BE POSSIBLE FRIDAY AFTERNOON AND EVENING...BUT THE GREATEST
THREAT APPEARS TO BE WELL TO THE SOUTH AND SOUTHEAST OF THE
TERMINALS. WINDS WILL BE ON THE LIGHT SIDE.
&&
.PREV DISCUSSION... /ISSUED 356 PM CDT THU SEP 25 2014/
SHORT TERM...
A SMALL MID-LVL CYCLONIC CIRCULATION CONTINUES TO INFLUENCE THE
WEATHER ACROSS THE CWA AS IT SLOWLY DRIFTS TO THE SW ACROSS SE NM.
THIS CIRCULATION HAS MAINTAIN A BROAD AREA OF SHOWERS ACROSS THE SW
SPLNS MUCH OF THE DAY...ALTHOUGH THERE HAS BEEN A NOTICEABLE
WEAKENING TREND THE PAST FEW HOURS. THE SHOWER ACTIVITY AND
CONSIDERABLE CLOUD COVER HAVE KEEP TEMPERATURES RELATIVELY
COOL...NAMELY MID 60S SW TO NEAR 80 EAST.
FOR THE REMAINDER OF THIS AFTERNOON AND EVENING...IT APPEARS THAT
INSTABILITY WILL REMAIN UNIMPRESSIVE DUE TO THE COOL
TEMPS...ALTHOUGH THERE IS A BIT OF A MID-LVL COOL POCKET THAT MIGHT
SUPPORT MLCAPES UP TO 1000 J/KG OR SO IN AREAS WHERE SURFACE TEMPS
APPROACH 80F. IN ADDITION...HIGHER UP AT THE JET STEAM LEVEL A SHEAR
AXIS MAY SUPPLY SOME DIVERGENCE AND LIFT. THE RESULT IS THAT WE
SHOULD CONTINUE TO SEE A CHANCE OF SHOWERS AND PERHAPS A FEW
T-STORMS THROUGH THE EVENING...FOCUSED ON THE WRN AND SRN SOUTH
PLAINS...BUT THE COVERAGE AND INTENSITY OF THE ACTIVITY SHOULD BE
SUBSTANTIALLY LOWER THAN WHAT OCCURRED WEDNESDAY. THE MOISTURE
REMAINS QUITE DEEP ACROSS THE WESTERN ZONES AND WE COULD SEE SOME
LOCALLY HEAVIER RAINFALL TOTALS...BUT WITH THE MODEST INSTABILITY IN
PLACE THIS WILL BE LESS LIKELY AND DUE MORE TO THE SLOW MOVEMENT AND
NOT THE RAINFALL RATES. A FEW SHOWERS COULD LINGER OUT WEST
OVERNIGHT WITH A GENERAL DECREASING TREND.
ON FRIDAY...THE LOW SHOULD MOVE FARTHER AWAY INTO SW TX...BUT N-NE
FLOW ALOFT WILL MAINTAIN A BROAD UPPER LOW OVER MUCH OF WEST TEXAS.
IN ADDITION...A SLUG OF GULF MOISTURE WILL BE BE MOVING TO THE W-NW
ACROSS TX AND MAY NUDGE INTO THE SRN ROLLING PLAINS FRIDAY
AFTERNOON. WHEN COMBINED WITH DIABATIC HEATING AND THE LINGERING
WEAKNESS IN THE MID-LVL HEIGHT FIELD ACROSS THE AREA...THIS MIGHT BE
ENOUGH TO GIN UP A FEW SHOWERS AND WEAK T-STORMS IN THAT AREA.
OTHERWISE...THE AREA SHOULD WARM UP A BIT BUT REMAIN SEASONABLY COOL
WITH HIGHS IN THE 70S AND LOWER 80S.
LONG TERM...
RECENT LIGHT FLOW REGIME REMAINS ON TRACK TO AMPLIFY BY LATE THIS
WEEKEND AND CONTINUE THROUGH THE START OF OCTOBER. THE PRIMARY
FEATURE RESPONSIBLE FOR THIS CHANGE IS A DEEP AND VIGOROUS UPPER
TROUGH NOW MAKING LANDFALL OVER MUCH OF THE PACIFIC COAST. AS THIS
WAVE JOGS EAST IN THE DAYS AHEAD...RISING HEIGHTS WILL OVERSPREAD
THE SRN PLAINS AND GRADUALLY RID US OF AN AXIS OF MID-LEVEL
MOISTURE THAT HAS OCCUPIED THE REGION FOR THE PAST WEEK. UNTIL
THIS RIDGE REACHES OUR AREA...THERE MAY BE A WINDOW FOR LIGHT
PRECIP ON SAT UNDER A DECAYING IMPULSE THAT CONTINUES TO WOBBLE
AROUND SWRN TX. MODEL SOUNDINGS HOWEVER ARE QUITE LACKLUSTER WITH
BOTH LIFT AND POTENTIAL INSTABILITY...SO WE ARE CHOOSING TO OMIT
PRECIP MENTION ON SAT ATTM. RISING HEIGHTS BY SUN AND A VEERING OF
MID-LEVEL WINDS TO THE WEST WILL GIVE RISE TO A CAPPING LAYER
ALOFT AND SHOULD KEEP ANY BOUNDARY LAYER CUMULUS WELL SHY OF THEIR
LFC HEIGHTS.
MONDAY AND TUESDAY ARE LOOKING A BIT MORE PROMISING FOR ACTIVE
WEATHER IN THE FORM OF ORGANIZED CONVECTION THANKS TO THE ARRIVAL
OF CYCLONIC SWLY FLOW IN THE BASE OF THE AFOREMENTIONED PACIFIC
TROUGH. DESPITE THE CORE OF THIS UPPER TROUGH/LOW LIFTING NORTH OF
THE FORECAST AREA WITH A NEGATIVE TILT...A RESPECTABLE UPPER JET
MAXIMA IN THE BASE OF THE TROUGH ALONG WITH A SURFACE TROUGH AND
APPROACHING DRYLINE FIT OUR PATTERN RECOGNITION FOR SOME PRECIP...
MAINLY ACROSS OUR NORTH NEAREST THE CORE OF BETTER HEIGHT FALLS.
GFS AND ECM ARE IN RATHER GOOD AGREEMENT WITH THE TIMING AND
STRUCTURE OF THE EJECTING WAVE BY MON NIGHT...SO POPS WERE RAISED
MODESTLY OVER MUCH OF THE AREA. SHEAR AND INSTABILITY BOTH LOOK TO
MAKE A GOOD SHOWING...SO SEVERE TSTORMS ARE CERTAINLY POSSIBLE.
MODELS DO DIVERGE BY TUE WITH THE FLOW REGIME BEHIND THE BASE OF
THE TROUGH AS THE ECMWF IS NOW MORE STABLE WITH S/W RIDGING WHILE
THE GFS DEEPENS A TRAILING TROUGH AXIS. THE THEME FOR A COUPLE
DAYS NOW HAS BEEN FOR A PERSISTENT CYCLONIC FLOW FOR TUE-THU...SO
WE WILL REFRAIN FROM THE ECM/S CHANGE OF HEART AND KEEP SOME
PRECIP OVER THE ERN HALF OF THE AREA AHEAD OF AN OSCILLATING
DRYLINE. THIS STORY COULD REPEAT FOR THE REMAINDER OF THE
WEEK...BUT WITH DEEPER WESTERLY FLOW ALOFT A DRIER AND MORE
EASTERLY DRYLINE POSITION MAY BE THE WAY TO GO AFTER TUE. MODELS
DIVERGE EVEN FURTHER THEREAFTER AND NOW DELAY A CANADIAN COLD
FRONT UNTIL JUST BEYOND THIS FORECAST WINDOW /I.E. NEXT THU/.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 54 76 55 76 56 / 10 10 10 10 0
TULIA 54 77 56 77 57 / 10 10 10 10 10
PLAINVIEW 55 77 56 77 57 / 10 10 10 10 10
LEVELLAND 55 76 57 77 58 / 20 10 10 10 10
LUBBOCK 56 76 57 77 58 / 10 10 10 10 10
DENVER CITY 56 76 59 77 59 / 30 10 10 10 10
BROWNFIELD 56 77 59 77 59 / 20 10 10 10 10
CHILDRESS 59 83 61 81 61 / 10 10 10 10 10
SPUR 57 79 61 80 60 / 10 10 10 10 10
ASPERMONT 59 82 62 82 62 / 10 20 20 10 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
23/07/23
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
328 PM CDT FRI SEP 26 2014
.TONIGHT - CONFIDENCE...MEDIUM
SURFACE HIGH CONTINUES TO DOMINATE. BROAD 500 MILLIBAR CIRCULATION
ACRS NRN MO/SRN IA PROGGD TO RETROGRADE A BIT TO THE NORTHWEST. MAIN
CONCERN WILL BE FOG DEVELOPMENT. NOT MUCH CHANGE FROM LAST NIGHT
OTHER THAN SLIGHTLY HIGHER DEWPOINTS. ALSO NOTICING AN INCREASE IN
SE WINDS WITHIN A FEW OF THE LOWER GATES ON RAP SOUNDINGS. FOG WILL
BE QUITE SHALLOW AS COLUMN IS MOISTURE STARVED. NAM MOS A LITTLE
MORE ROBUST THAN THE GFS MOS BUT THIS IS TYPICAL. SREF PROBS NOT TOO
EXCITED BUT OVERALL PERSISTENCE SEEMS PRUDENT GIVEN THE OVERALL
STAGNANT PATTERN. WILL NOT HOIST AN ADVISORY AT THIS TIME AS
CONFIDENCE IN WIDESPREAD DENSE NOT HIGH AT THIS TIME...BUT POTENTIAL
THERE FOR AT LEAST PATCHY DENSE FOG.
.SATURDAY - CONFIDENCE...HIGH
UPPER LOW PROGGD TO BE AROUND NW IA/SW MN. HIGH PRESSURE RIDGE
DOMINATES WITH THE DRY AND STABLE AIRMASS PERSISTING. MORNING FOG
TRENDS WILL BE THE MAIN FOCUS WITH ANY LINGERING FOG LIKELY TO BURN
OFF IN MUCH THE SAME FASHION AS FRIDAY MORNING. 925 TEMPS AROUND 17-
18C...SO HIGHS WELL INTO THE 70S.
.SATURDAY NIGHT THROUGH MONDAY...FORECAST CONFIDENCE - MEDIUM.
MORE FOG POSSIBLE SATURDAY NIGHT AS BOUNDARY LAYER WINDS REMAIN
AROUND 10 KNOTS OR LESS. SFC DEWPTS CONTINUE TO SLOWLY RISE EACH
DAY DUE TO THE STAGNATING AIR MASS. HENCE THE LIGHT WINDS AND
MOSTLY CLEAR SKIES SHOULD ALLOW OVERNIGHT TEMPS TO FALL BELOW THE
DAYTIME CROSS OVER TEMP ONCE AGAIN.
OTHERWISE...THE QUIET CONDITIONS WILL CONTINUE THROUGH MONDAY
MORNING. MOST OF THE SHORT TERM GUIDANCE SHOWING AN AMPLIFYING
SHORT WAVE TROUGH FURTHER STRENGTHENING ALONG BAROCLINIC ZONE DRAPED
ACROSS NORTHERN GTLAKES SUN NGT AND MON. THIS HIGHER AMPLITUDE WAVE
AND LOW PRESSURE RESULTS IN QUICKER SOUTHWARD MOVEMENT OF BACKDOOR
COLD FRONT ACROSS WESTERN GTLAKES ON MONDAY. ELEVATED MOISTURE
STILL LIMITED AS FRONT CROSSES REGION SO FOR NOW...WL CONTINUE SCHC
WORDING IN THE NORTHEAST CWA...CLOSER TO UPPER LEVEL CIRCULATION.
LATER PERIODS OF NAM REMAIN OUTLIER WITH ITS SLOWER SWD MOVEMENT.
IF THIS TREND CONTINUES WL NEED TO BUMP UP WINDS AND SPEED UP MORE
ABRUPT WIND CHANGE LATER MONDAY INTO MONDAY EVENING.
.MONDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE - MEDIUM TRENDING
TOWARD LOW.
AS MENTIONED ABOVE...MEDIUM RANGE GUIDANCE IN GOOD AGREEMENT ON
AMPLIFYING SHORT WAVE TROUGH OVER WESTERN GTLAKES CONTINUING TO
STRENGTHEN AS IT TRACKS EWD MONDAY AND MONDAY NIGHT. STRONGER SHORT
WAVE WILL PULL BACKDOOR CDFNT SWD ACROSS SRN WI ABOUT 12 HOURS
EARLIER THAN THOUGHT 24 HOURS AGO. HENCE CDFNT NOW EXPECTED TO
ADVANCE SOUTH OF SRN WI/LAKE MI BY 00Z/TUE. WL KEEP A CHANCE FOR -
SHRA IN THE EVE IN PARTS OF EAST BUT DRIER...COOLER AIR WILL END
THREAT OVERNIGHT. LIKELY SOME LOW CLOUDS/STRATUS WL ACCOMPANY PUSH
OF COLDER AIR POST FRONTAL PASSAGE.
SHORT WAVE RIDGING SHOULD RESULT IN QUIET AND DRY CONDITIONS
RETURNING AT LEAST TEMPORARILY TUE/TUE NGT.
MEANWHILE...BROADENING LONG WAVE TROUGH OVER WRN CONUS WILL RESULT
IN INCREASING SLY WINDS OVER THE WRN GTLAKES AROUND MID WEEK AS
SEVERAL PIECES OF SHORT WAVE ENERGY ROTATE NORTHWARD ACROSS THE
NORTHERN PLAINS/UPPER MIDWEST. AS A RESULT...COLUMN PRECIPITABLE
WATER INCREASES TO AROUND 1.5 INCHES BY 00Z/THU. INITIAL SURGE OF
MOISTURE MAY SET OFF PRECIPITATION ON WED...WITH BETTER CHANCE IN
THU/THU NGT TIME FRAME WHEN STRONG CDFNT AND SHARP MID-LEVEL SHORT
WAVE PASS ACROSS THE REGION. 00Z MEDIUM RANGE GUIDANCE RAPIDLY
DIVERGED AFTER THAT AS GFS CONTINUED TO CARVE OUT COLD LONG WAVE
TROUGH OVER THE REGION...WHILE ECMWF RETURNS TO WARMER...MORE ZONAL
FLOW FOR THE WEEKEND. HOWEVER 12Z ECMWF/GFS FLIP FLOPPED SOMEWHAT
WITH ECMWF NOW SHOWING COLD AIR SURGING INTO SRN WI FOR THE
WEEKEND...WHILE GFS TRENDS TOWARD MORE ZONAL FLOW. HENCE LOW
CONFIDENCE IN LATE PERIODS
DISAGREEMENT BEGINS UPSTREAM OVER WRN CONUS AND NORTHERN PACIFIC WRT
AMOUNT OF AMPLIFICATION OF NORTHERN PACIFIC TROF AND RIDGING OVER
WRN CONUS. GFS ENSEMBLE MEMBERS SHOWING LARGE VARIABILITY IN UPPER
LEVEL FEATURES DURING THIS PERIOD...SO WOULD OPT FOR AN AVERAGE OF
ALL GUIDANCE FOR NEXT WEEKEND.
&&
.AVIATION/00Z TAFS/...MOSTLY VFR PERIOD WITH SURFACE HIGH HAVING
STRONG INFLUENCE WITH DRY AND STABLE AIRMASS. WATER VAPOR/RAP SHOWS
RATHER BROAD CIRCULATION CENTER VCNTY NW MO/SE IA. WILL WATCH FOR
MORE FOG DEVELOPMENT TONIGHT WITH SOME IFR VSBYS POSSIBLE. ANY FOG
WILL DISSIPATE SATURDAY MORNING AS HEATING KICKS IN.
&&
.MARINE...FOG WILL LIKELY DEVELOP ONCE AGAIN OVER EASTERN WI THIS
EVENING AND OVERNIGHT AND SOME OF THIS FOG MAY DEVELOP OVER THE
NEARSHORE WATERS AS WELL.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/SATURDAY/AVIATION/MARINE...PC
SATURDAY NIGHT THROUGH FRIDAY...MBK
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
1018 PM PDT Sat Sep 27 2014
.Synopsis...
Cool weather with lingering showers, mainly over the Sierra
Nevada overnight and Sunday. Dry and warmer next week with
locally breezy north winds around mid week.
&&
Discussion...
Upper low is over western Nevada this evening with moisture
wrapping westward into Norcal. Scattered showers and isolated
thunderstorms occurred over mainly the mountains during the late
afternoon/early evening. A lull in the activity is presently over
the area. The next band of precip rotating around the low over
northern Nevada will move over the Sierra towards morning per
latest HRRR guidance. Have update forecast to adjust for this
timing...increasing pops central/srn Sierra in the morning period
and introducing slight shower chances west through the southern
sac/nrn san joaquin valleys. Ended the Winter weather advisory an
hour early due to the large break in precip.
.Previous Discussion...
Wrap-around moisture beginning to enter our backdoor and spread SWwd
over the Siernev from Wrn NV as suggested by the higher resolution
models. Several tenths of an inch of QPF is forecast along the
deformation zone over the Siernev this afternoon into this evening.
This is expected to result in several inches of additional/ new snow
accumulations as indicated by the NAM/GFS snow accumulation progs
over the Siernev mainly S of I-80. Snow levels will be near/above
8 kft so only the higher passes south of HWY 50 will primarily be
affected. WSW was issued in the morning update for the first and
early season snowfall.
Marginal instability forecast over the Siernev this afternoon into
the evening with potential for isolated thunderstorms. Although
cloud cover will limit heating...moderate shear and strong cyclonic
flow along the deformation axis of the upper low could result in
isolated thunder over the crest from Plumas county Swd...although
better afternoon heating is likely over the foothills ahead of the
building cumulus.
The upper low continues Ewd on Sunday but the Sierra remains under
cyclonic flow and weak instability. Showers will again be a
possibility but should remain over the higher elevations as the low
moves east. After the embedded vort max or short wave rotates Swd
around the low Sun afternoon...cloud cover over the valley should
allow for a bit of warming.
A positively tilted ridge will move inland behind the low on Mon
ending the shower threat...clearing skies and begin a warming trend.
The ridge will be knocked down temporarily by another low pressure
trough but this time moving inland well north of the region. The
main impact of this system will be a slight cooling effect Tuesday
and a few clouds over the far Nrn portion of the CWA. JHM
.Extended Discussion (Wednesday through Saturday)
High pressure ridging will dominate the extended forecast bring a
warming trend with dry weather through the end of the week. A weak
shortwave will pass by to the north on Wednesday, with breezy
north winds picking up over the Sacramento Valley and northern
mountains. Gusty northeast winds over mountain ridges and through
canyons expected early Thursday. Temperatures will be several
degrees above normal on Wednesday and rise to well above normal by
the end of the week. This means highs in the low to mid 90s for
the Valley and eastern Delta by Friday and Saturday, with
decreasing winds. The foothills should see some upper 80s for the end
of the week, with even the Sierra in the 60`s and 70s. The
prospects for any precipitation look quite low for next week. EK
&&
.Aviation...
VFR conditions for TAF sites overnight. Scattered showers
expected to continue over the Sierra tonight into Sunday. Sierra
snow over 7500 feet tonight, with local IFR/LIFR conditions.
&&
.STO Watches/Warnings/Advisories...
None.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
323 AM MDT SUN SEP 28 2014
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 321 AM MDT SUN SEP 28 2014
LIGHT TO MODERATE RAINSHOWERS CONTINUE THIS MORNING...STRADDLING
BOTH SIDES OF THE UT/CO BORDER WITH A FEW RUMBLES OF THUNDER MIXED
IN. UPPER LEVEL SUPPORT WANED LAST NIGHT AND THIS MORNING AS A JET
STREAK CURVES BACK AROUND THE CLOSED LOW OVER NV. THIS STREAK IS
THE SUPPORT THAT`S CAUSING THE RAINSHOWERS. A STRONGER JET STREAK
IS PROGGED TO ROUND THE BASE OF SAID LOW PRESSURE AND MOVE ACROSS
THE CWA THIS AFTERNOON AND EVENING. FOR THE REMAINDER OF THE
MORNING HOURS...RAINSHOWERS WILL CONTINUE WITH A FEW BEING LOCALLY
HEAVY BUT WITH THE LOW SLOWLY MOVING E AND PRECIP FOLLOWING
SUIT...FLASH FLOOD CONCERNS WILL LOWER SO WILL DROP ERN UT FLASH
FLOOD WATCH WITH THIS MORNINGS PACKAGE. THE WATCH FOR WRN COLORADO
STILL STAY IN PLACE HOWEVER WITH SHOWERS AND EMBEDDED STORMS
CONTINUING TO TRACK EWRD. THE HRRR IS AGAIN PERFORMING WELL AND
IS INDICATING BY 0700L THAT PRECIP SHOULD BE ENDING FOR ERN UT
WHILE MUCH OF WRN COLORADO...EXCEPT THE NRN MTNS...WILL BE SEEING
SOME RAINFALL.
NEXT CONCERN WILL BE STORMS THIS AFTERNOON. CURRENT IR SATELLITE
SHOWS PLENTY OF DRY AIR OVER WRN/SRN UT THAT WILL MOVE INTO OUR
CWA TODAY. AS THIS OCCURS...BULK SHEAR WILL REMAIN ESPECIALLY
HIGH AND THIS MIXED WITH AFTERNOON HEATING AND UPPER LEVEL
DYNAMIC SUPPORT WILL LEND ITSELF FOR SOME STRONG THUNDERSTORMS
THIS AFTERNOON. SOME STORMS MAY REACH SEVERE LIMITS WITH WIND
GUSTS OF 50 TO 60 MPH POSSIBLE ALONG WITH HALF- INCH SIZED HAIL OR
LARGER UNDER AND NEAR THE STRONGEST CELLS. HRRR ALSO SHOWING THIS
CONVECTION FORMING FROM ABOUT 3PM ONWARDS. AS YOU CAN IMAGINE...AN
ACTIVE AFTERNOON IS EXPECTED.
SUNDAY NIGHT A SIGNIFICANT SPOKE OF ENERGY DIGS INTO THE BASE OF
THE LOW ELONGATING IT SOUTH TO NORTH. THE JET STREAK LIFTS NORTH
OF THIS AREA AND THE DRY SLOT LOWERS PRECIP WATER VALUES TO 0.25
SOUTH...0.5 INCH NORTH. THIS BRINGS A DIMINISHING OF SHOWERS
THROUGH THE EVENING AND OVERNIGHT. THE SOUTHERN SPOKE ROTATES NE
WITH THE ASSOCIATED 80KT JET LIFTING THROUGH THE FOUR CORNERS IN
THE MORNING. ASSOCIATED SURFACE COLD FRONT UNDER THE JET SUPPORT
WILL PRODUCE SOME MORNING SHOWERS IN THE SW SAN JUAN MOUNTAINS IN
SPITE OF THE DRIER AIR. THE LOW OPENS AS IT LIFTS NE MONDAY
AFTERNOON PROVIDING SUPPORT FOR MAINLY OROGRAPHIC SHOWERS AND
STORMS THROUGH THE AFTERNOON. AFTERNOON TEMPERATURES WILL BE 5-10
DEGREES BELOW AVERAGE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 321 AM MDT SUN SEP 28 2014
SOME SHOWERS MAY CONTINUE OVER THE NORTH MONDAY NIGHT THROUGH
TUESDAY NIGHT IN ACTIVE NW FLOW WITH ONLY MARGINAL MOISTURE AND
INSTABILITY AVAILABLE. 700MB TEMPERATURES HOVER NEAR 0C MONDAY FOR
A SNOW POSSIBLE DOWN TO NEAR 9000 FT IN THE PARK RANGE. ANY SNOW
ACCUMULATION BELOW TIMBERLINE WILL MELT ON TUESDAY AS TEMPERATURES
RECOVER TO NEAR NORMAL.
THE JET STREAM WILL DROP DOWN FROM THE PACNW WEDNESDAY AND CARVE
OUT A RELATIVELY WEAK TROUGH THAT WILL MOVE OVER THE AREA WED
EVENING AND THURSDAY MORNING. SOME ISOLD SHOWERS/STORMS ARE
EXPECTED WITH SOME SNOWFALL FOR THE HIGHER ELEVATIONS UP NORTH.
MAYBE AN INCH OR TWO POSSIBLE. BY THURSDAY MORNING...HIGH PRESSURE
SETS UP OVER THE WRN GREAT BASIN KEEPING US IN NW FLOW FOR THE
REMAINDER OF THE LONG TERM PERIOD WITH DRY CONDITIONS EXPECTED.
TEMPERATURES WILL BE BELOW NORMAL FOR MUCH OF THE LONG TERM PERIOD
SLOWLY WARMING UP TOWARDS THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 321 AM MDT SUN SEP 28 2014
RAIN...RAINSHOWERS...AND EMBEDDED STORMS WILL CONTINUE THIS
MORNING CAUSING MVFR CONDITIONS FROM TIME TO TIME THOUGH BY AND
LARGE...VFR WILL BE THE PREDOMINANT FLIGHT CATEGORY. MORE ROBUST
CONVECTION IS EXPECTED TO FIRE THIS AFTERNOON AFTER 18Z WITH
COVERAGE AND INTENSITY REALLY GETTING GOING AFTER 21Z. SOME STORMS
WILL BE ON THE STRONG SIDE WITH GUSTY WINDS POSSIBLY REACHING
50MPH...POSSIBLY HIGHER...WITH HALF INCH SIZED HAIL ALSO POSSIBLE.
SOME CONVECTION WILL PERSIST OVERNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH UNTIL NOON MDT TODAY FOR COZ001>003-006-007-
009-011-013-017>022.
UT...NONE
&&
$$
SHORT TERM...TGR/JOE
LONG TERM...JOE/TGR
AVIATION...TGR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
604 AM EDT SUN SEP 28 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 603 AM EDT SUN SEP 28 2014
...ONE MORE UNSEASONABLY WARM DAY TODAY...AND QUITE LIKELY THE LAST
DAY WITH TEMPERATURES THIS HIGH FOR THE REST OF THE YEAR...
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...STRONG RIDGE THAT WAS
EXTENDING INTO NRN ONTARIO IS BEING SUPPRESSED BY SHORTWAVE TROF
THAT HAS BEEN MOVING ACROSS SOUTHERN CANADA. THIS TROF IS SUPPORTING
A SHARP COLD FRONT THAT CURRENTLY EXTENDS FROM SE ND TO JUST S OF
JAMES BAY. JUST BEHIND FRONT...TEMPS QUICKLY FALL OFF INTO THE 40S
AND 30S...GIVING AN IDEA OF THE DRAMATICALLY COLDER CONDITIONS THAT
WILL SWEEP INTO THE AREA FOR MON. MID LEVEL LOW THAT WAS CENTERED
ALONG THE IA/MO BORDER 24 HRS AGO HAS MOVED LITTLE...NOW OVER IA.
SCT/BKN MAINLY THIN HIGH CLOUDS TO THE NE OF THIS FEATURE HAVE
HELPED TO KEEP RADIATION FOG A LITTLE LESS WIDESPREAD AND LESS DENSE
EARLY THIS MORNING.
FCST SOUNDINGS SHOW LITTLE CHANGE IN TEMP PROFILE FROM YESTERDAY...
SO LARGELY UTILIZED YESTERDAYS MAX TEMPS AS A BASIS FOR TODAYS MAX
TEMPS. TEMP RISE THIS MORNING SHOULD ALSO FOLLOW A SIMILAR DIURNAL
CURVE TO WHAT OCCURRED YESTERDAY MORNING. PRETTY GOOD CHC RECORD
HIGH OF 77F FOR NWS KMQT SITE WILL FALL TODAY. SHARP COLD FRONT TO
THE N WILL DRIFT S TODAY AND SHOULD REACH THE KEWEENAW LATE IN THE
AFTN. AS IS CURRENTLY NOTED WITH FRONTAL BOUNDARY...PCPN WILL
CONTINUE TO OCCUR MOSTLY ON THE COLD SIDE OF THE SFC COLD FRONT AS
NICE FRONTOGENETICAL CIRCULATION UNDER RIGHT ENTRANCE OF UPPER JET
WILL CONTINUE TO SUPPORT PCPN ON THE COLD SIDE OF THE SFC FRONT.
THAT SAID...WEAK PRES GRADIENT AHEAD OF FRONT WILL ALLOW LAKE
BREEZES TO DEVELOP TODAY. WITH A FEW HUNDRED J/KG OF MLCAPE...LAKE
BREEZE MAY BE SUFFICIENT TO KICK OFF ISOLD SHRA THIS AFTN ACROSS
PORTIONS OF THE CNTRL AND ERN FCST AREA. MOST HIGH RES MODEL
GUIDANCE CONTINUES TO SHOW THIS POTENTIAL.
SFC COLD FRONT WILL CONTINUE TO DRIFT S TONIGHT WITH PCPN REMAINING
MOSTLY ON THE COLD SIDE OF THE BOUNDARY...SUPPORTED BY
FRONTOGENETICAL CIRCULATION AS DISCUSSED ABOVE. TRAILING SHORTWAVE
CURRENTLY OVER SCNTRL CANADA WILL DIG INTO THE UPPER GREAT LAKES
MON. WITH BEST OVERLAP OF FGEN AND DEEP LAYER FORCING FROM SHORTWAVE
PER QVECTORS PASSING JUST N AND E OF FCST AREA...HEAVIER/STEADIER
SHRA/RA SHOULD PASS N AND E OF THE AREA. HOWEVER...DECENT FORCING
STILL SUPPORTS LIKELY TO CATEGORICAL POPS SPREADING SE TO THE
KEWEENAW AFTER MIDNIGHT TONIGHT AND TO WRN AND NRN UPPER MI BY 12Z
MON.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 326 AM EDT SUN SEP 28 2014
MONDAY WILL BE A SIGNIFICANT CHANGE IN THE WEATHER FOR UPPER
MICHIGAN...AS A COLD FRONT SWEEPS SOUTHEAST ACROSS THE AREA LATE
SUNDAY NIGHT THROUGH MONDAY. AS THIS OCCURS...EXPECT A BAND OF
SHOWERS TO BE MOVING ACROSS THE AREA ALONG AND BEHIND THE SURFACE
COLD FRONT BEFORE SINKING SOUTHEAST OF THE AREA ON MONDAY EVENING.
EVEN AS A BULK OF THE RAIN HAS SHIFTED OVER THE SOUTHEAST HALF OF
THE CWA ON MONDAY AFTERNOON...STILL EXPECT PLENTY OF LOW CLOUDS AND
LIGHT RAIN/DRIZZLE OVER THE AREA...ESPECIALLY THOSE FAVORED BY
NORTH-NORTHEAST UPSLOPE WINDS. IN ADDITION...WITH 900MB TEMPS
AROUND -1C AND LAKE SUPERIOR TEMPS BETWEEN 6-12C WOULD EXPECT AT
LEAST SOME LAKE ENHANCEMENT FOR THE AREAS NEAR LAKE SUPERIOR. WITH
INVERSION HEIGHTS RUNNING AROUND 3-3.5KFT DON/T EXPECT THE RAIN TO
BE TOO HEAVY...BUT ENOUGH TO LEAD TO A PERSISTANT LIGHT RAIN. WILL
CONTINUE TO SHOW LIKELY TO DEFINITE POPS IN THE FAVORED WIND
DIRECTIONS NEAR LAKE SUPERIOR AND AT LEAST CHANCES ELSEWHERE INTO
THE EVENING HOURS ON MONDAY. MODELS THEN SHOWING INVERSION HEIGHTS
FALLING THROUGH THE NIGHT UNDER THE INCREASED SUBSIDENCE FROM THE
HIGH PRESSURE RIDGE (HIGH CENTERED IN NORTHEAST ONTARIO) MOVING INTO
THE AREA. THUS...WILL SHOW DECREASING POPS THROUGH THE NIGHT AND
EVENTUALLY CLOUD COVER THROUGH THE DAY ON TUESDAY INTO TUESDAY
NIGHT. THE COMBINATION OF THE RAIN WITH STIFF NORTH-NORTHEAST WINDS
(15-25KTS) AND AFTERNOON TEMPERATURES IN THE MID 40S (30-35
DEGREES COLDER THAN THIS AFTERNOON) OVER THE NORTH HALF WILL MAKE
FOR A SIGNIFICANTLY DIFFERENT DAY THAN WHAT HAS BEEN EXPERIENCED
OVER THE LAST SEVERAL DAYS.
AS THE U.P. FINALLY STARTS TO BREAK OUT OF THE CLOUDS FROM MONDAY/S
SYSTEM...THE NEXT UPPER TROUGH WILL BE WORKING TOWARDS THE AREA ON
TUESDAY NIGHT AND BRING THE NEXT PERIOD OF UNSETTLED WEATHER TO THE
AREA FOR WEDNESDAY AFTERNOON THROUGH SATURDAY. THIS PERIOD OF
UNSETTLED WEATHER WILL BE ASSOCIATED WITH THE UPPER TROUGH
CURRENTLY OVER THE WESTERN CONUS SHIFTING EAST THROUGH THE AREA
DURING THAT PERIOD. THE FIRST WAVE FROM THAT UPPER TROUGH WILL MOVE
INTO THE AREA ON WEDNESDAY AFTERNOON AHEAD OF A WARM FRONT LIFTING
NORTHEAST TOWARDS THE AREA FROM A LOW NEAR LAKE WINNIPEG. WILL SHOW
INCREASING POPS FROM SOUTHWEST TO NORTHEAST FOR WEDNESDAY AFTERNOON
INTO WEDNESDAY NIGHT...WITH THE HIGHEST POPS (LIKELY) RUNNING ALONG
THE COLD FRONT THAT WILL BE MOVING THROUGH WESTERN AND CENTRAL
UPPER MICHIGAN LATE WEDNESDAY NIGHT AND THURSDAY. AS THIS COLD
FRONT IS SLOWLY WORKING EAST ACROSS THE AREA...A STRONG SHORTWAVE
DIVING SOUTHEAST THROUGH THE UPPER TROUGH WILL POTENTIALLY LEAD TO
THE INTENSIFICATION OF A LOW IN THE MID MISSISSIPPI VALLEY ON
THURSDAY EVENING. THIS LOW WILL CONTINUE TO INTENSIFY AS IT LIFTS
NORTHEAST ACROSS UPPER MICHIGAN ON FRIDAY MORNING AND THEN
NORTH-NORTHEAST INTO CANADA. WILL CONTINUE LIKELY POPS AS THIS LOW
MOVES THROUGH...ALTHOUGH CONFIDENCE IN THE STRENGTH IS LIMITED DUE
TO THE VARYING SOLUTIONS SHOWN IN THE MODELS (NOT UNEXPECTED WITH
UPSTREAM PHASING OF STRONG SHORTWAVES). THE 12Z ECMWF ENSEMBLE
MEMBERS ARE NOT MUCH OF A HELP WITH AROUND HALF OF THEM NOT SHOWING
A LOW RIDING UP THE COLD FRONT. WITH 12Z ECMWF AND 00Z GFS AT LEAST
SIMILAR IN THEIR IDEAS (ALTHOUGH GFS IS MUCH SLOWER IN DEPARTING THE
LOW)...WILL FOLLOW THAT IDEA FOR NOW FOR POPS (CHANCE/LIKELY) AND
WIND (GUSTY NORTHWEST WINDS TO 30KTS ON FRIDAY NIGHT) FORECAST.
LATE ARRIVING 00Z ECMWF HAS BACKED AWAY FROM THE LOW PRESSURE SYSTEM
AND JUST KEEPING A BROAD SURFACE TROUGH MOVING THROUGH. BASED OFF
THE 12Z ECMWF ENSEMBLE MEMBERS...THAT DOESN/T SEEM TO UNREASONABLE.
SATURDAY SHOULD SEE A DIMINISHING OF BOTH OF THOSE AS THE LOW PULLS
OUT OF THE AREA AND A HIGH PRESSURE RIDGE MOVES IN FROM THE
SOUTHWEST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 122 AM EDT SUN SEP 28 2014
DRY AIR ASSOCIATED WITH HIGH PRES CENTERED OVER THE EASTERN GREAT
LAKES WILL CONTINUE TO BRING VFR CONDITIONS TO KIWD/KCMX/KSAW UNTIL
THIS EVENING. AS HAS BEEN THE CASE THE LAST FEW NIGHTS...SHALLOW
RADIATION FOG WILL DEVELOP AT NIGHT AND AFFECT KSAW. LOW-LEVEL WINDS
OVERNIGHT WILL HAVE MORE OF A DOWNSLOPE WESTERLY COMPONENT...SO AT THIS
POINT...NOT ANTICIPATING KSAW TO DROP BLO MVFR TOWARD DAYBREAK. A
COLD FRONT BOOSTED BY THE LAKE BREEZE WILL BRING VEERING WINDS LATE
THIS AFTERNOON AT CMX AND THIS EVENING AT SAW AND IWD. THERE IS SOME
UNCERTAINTY ON HOW QUICKLY THE FRONT WILL MOVE IN WITH LOWER MVFR
CLOUDS IN ITS WAKE. SOME SHOWERS MAY ALSO BE POSSIBLE ALONG THE LAKE
BREEZE BOUNDARY INTO N CNTRL UPPER MI LATE THIS AFTERNOON...BUT
CONFIDENCE ON ITS IMPACT AT SAW IS TOO LOW TO MENTION IN THE TAF.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 603 AM EDT SUN SEP 28 2014
SHARP COLD FRONT CURRENTLY OVER NRN ONTARIO WILL DROP S...PASSING
ACROSS LAKE SUPERIOR THIS AFTN AND TONIGHT. WITH A WEAK PRES
GRADIENT AHEAD OF FRONT...WINDS WILL REMAIN ON THE LIGHT SIDE
TODAY...MOSTLY UNDER 20KT. ON THE FLIP SIDE...DRAMATIC CHANGES WILL
OCCUR AFTER THE FRONT PASSES. STRONG COLD AIR ADVECTION COMBINED
WITH POST FRONTAL PRES RISES WILL RESULT IN N TO NE WINDS OF 20-30KT
ACROSS MUCH OF LAKE SUPERIOR WITH A FEW GALE FORCE GUSTS POSSIBLE
ACROSS CENTRAL PORTIONS OF THE LAKE TONIGHT INTO MON MORNING. WINDS
WILL THEN GRADUALLY DIMINISH MON AFTN AND NIGHT AS HIGH PRES BUILDS
OVER NRN ONTARIO. WINDS UNDER 20KT WILL BE THE RULE TUE THRU THU.
HOWEVER...AS PRES GRADIENT TIGHTENS SOME ON WED BTWN DEPARTING HIGH
PRES AND AN APPROACHING COLD FRONT...SOUTHERLY WINDS MAY BE A LITTLE
STRONGER ON WED...MAINLY OVER ERN LAKE SUPERIOR. LOOKING FARTHER
OUT...THERE ARE SOME HINTS THAT A STRENGTHENING FALL STORM SYSTEM
WILL LIFT THRU THE UPPER LAKES LATE WEEK...BRINGING THE POTENTIAL
FOR GALES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...JLB
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
327 AM EDT SUN SEP 28 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 347 PM EDT SAT SEP 27 2014
...ONE MORE UNSEASONABLY WARM DAY IN STORE FOR SUNDAY...
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A STRONG RIDGE OVER MUCH
OF THE E HALF OF THE CONUS. 585-588 DECAMETER 5H HIGHS OVER THE UPPER
GREAT LAKES HAVE RESULTED IN INLAND HIGH TEMPS IN THE UPPER 70S TO
LOWER 80S ACROSS MUCH OF THE FORECAST AREA THIS AFTERNOON UNDER
MOSTLY SUNNY SKIES.
ANOTHER QUIET/CLEAR NIGHT IS EXPECTED TONIGHT UNDER THE INFLUENCE OF
THE HIGH PRESSURE RIDGE. MIN TEMPS SHOULD BE A LITTLE BIT HIGHER
THAN SATURDAY MORNINGS MINS DUE TO SOME INCREASE IN PRECIPITABLE
WATER. EXPECT MORE SHALLOW FOG FORMATION MAINLY WELL INLAND FROM
LAKE SUPERIOR. DOWNSLOPING SOUTHERLY WIND AND ASSOC MIXING SHOULD
GENERALLY PROHIBIT FOG FORMATION NEAR LAKE SUPERIOR.
EXPECT ONE MORE UNSEASONABLY WARM DAY ON SUNDAY. MIXING 850 MB OF
13-14C TO SFC SHOULD AGAIN YIELD HIGH TEMPS MAINLY IN THE UPPER 70S
AND LOWER 80S. ONSHORE SOUTH WINDS WILL RESULT IN COOLER TEMPS
AROUND 70S ALONG THE LAKE MI SHORELINE. KEPT IN SLIGHT CHC POPS FOR
SHRA OVER THE NCNTRL FCST AREA WHERE MODELS HINT THAT DEVELOPMENT OF
LAKE BREEZE OFF LAKE BREEZE COULD PROVIDE FOCUS FOR ISOLD
CONVECTION. MODIFIED NAM SOUNDINGS FOR 78/58 YIELD SBCAPE 200-300
J/KG WITH MINIMAL CIN.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 326 AM EDT SUN SEP 28 2014
MONDAY WILL BE A SIGNIFICANT CHANGE IN THE WEATHER FOR UPPER
MICHIGAN...AS A COLD FRONT SWEEPS SOUTHEAST ACROSS THE AREA LATE
SUNDAY NIGHT THROUGH MONDAY. AS THIS OCCURS...EXPECT A BAND OF
SHOWERS TO BE MOVING ACROSS THE AREA ALONG AND BEHIND THE SURFACE
COLD FRONT BEFORE SINKING SOUTHEAST OF THE AREA ON MONDAY EVENING.
EVEN AS A BULK OF THE RAIN HAS SHIFTED OVER THE SOUTHEAST HALF OF
THE CWA ON MONDAY AFTERNOON...STILL EXPECT PLENTY OF LOW CLOUDS AND
LIGHT RAIN/DRIZZLE OVER THE AREA...ESPECIALLY THOSE FAVORED BY
NORTH-NORTHEAST UPSLOPE WINDS. IN ADDITION...WITH 900MB TEMPS
AROUND -1C AND LAKE SUPERIOR TEMPS BETWEEN 6-12C WOULD EXPECT AT
LEAST SOME LAKE ENHANCEMENT FOR THE AREAS NEAR LAKE SUPERIOR. WITH
INVERSION HEIGHTS RUNNING AROUND 3-3.5KFT DON/T EXPECT THE RAIN TO
BE TOO HEAVY...BUT ENOUGH TO LEAD TO A PERSISTANT LIGHT RAIN. WILL
CONTINUE TO SHOW LIKELY TO DEFINITE POPS IN THE FAVORED WIND
DIRECTIONS NEAR LAKE SUPERIOR AND AT LEAST CHANCES ELSEWHERE INTO
THE EVENING HOURS ON MONDAY. MODELS THEN SHOWING INVERSION HEIGHTS
FALLING THROUGH THE NIGHT UNDER THE INCREASED SUBSIDENCE FROM THE
HIGH PRESSURE RIDGE (HIGH CENTERED IN NORTHEAST ONTARIO) MOVING INTO
THE AREA. THUS...WILL SHOW DECREASING POPS THROUGH THE NIGHT AND
EVENTUALLY CLOUD COVER THROUGH THE DAY ON TUESDAY INTO TUESDAY
NIGHT. THE COMBINATION OF THE RAIN WITH STIFF NORTH-NORTHEAST WINDS
(15-25KTS) AND AFTERNOON TEMPERATURES IN THE MID 40S (30-35
DEGREES COLDER THAN THIS AFTERNOON) OVER THE NORTH HALF WILL MAKE
FOR A SIGNIFICANTLY DIFFERENT DAY THAN WHAT HAS BEEN EXPERIENCED
OVER THE LAST SEVERAL DAYS.
AS THE U.P. FINALLY STARTS TO BREAK OUT OF THE CLOUDS FROM MONDAY/S
SYSTEM...THE NEXT UPPER TROUGH WILL BE WORKING TOWARDS THE AREA ON
TUESDAY NIGHT AND BRING THE NEXT PERIOD OF UNSETTLED WEATHER TO THE
AREA FOR WEDNESDAY AFTERNOON THROUGH SATURDAY. THIS PERIOD OF
UNSETTLED WEATHER WILL BE ASSOCIATED WITH THE UPPER TROUGH
CURRENTLY OVER THE WESTERN CONUS SHIFTING EAST THROUGH THE AREA
DURING THAT PERIOD. THE FIRST WAVE FROM THAT UPPER TROUGH WILL MOVE
INTO THE AREA ON WEDNESDAY AFTERNOON AHEAD OF A WARM FRONT LIFTING
NORTHEAST TOWARDS THE AREA FROM A LOW NEAR LAKE WINNIPEG. WILL SHOW
INCREASING POPS FROM SOUTHWEST TO NORTHEAST FOR WEDNESDAY AFTERNOON
INTO WEDNESDAY NIGHT...WITH THE HIGHEST POPS (LIKELY) RUNNING ALONG
THE COLD FRONT THAT WILL BE MOVING THROUGH WESTERN AND CENTRAL
UPPER MICHIGAN LATE WEDNESDAY NIGHT AND THURSDAY. AS THIS COLD
FRONT IS SLOWLY WORKING EAST ACROSS THE AREA...A STRONG SHORTWAVE
DIVING SOUTHEAST THROUGH THE UPPER TROUGH WILL POTENTIALLY LEAD TO
THE INTENSIFICATION OF A LOW IN THE MID MISSISSIPPI VALLEY ON
THURSDAY EVENING. THIS LOW WILL CONTINUE TO INTENSIFY AS IT LIFTS
NORTHEAST ACROSS UPPER MICHIGAN ON FRIDAY MORNING AND THEN
NORTH-NORTHEAST INTO CANADA. WILL CONTINUE LIKELY POPS AS THIS LOW
MOVES THROUGH...ALTHOUGH CONFIDENCE IN THE STRENGTH IS LIMITED DUE
TO THE VARYING SOLUTIONS SHOWN IN THE MODELS (NOT UNEXPECTED WITH
UPSTREAM PHASING OF STRONG SHORTWAVES). THE 12Z ECMWF ENSEMBLE
MEMBERS ARE NOT MUCH OF A HELP WITH AROUND HALF OF THEM NOT SHOWING
A LOW RIDING UP THE COLD FRONT. WITH 12Z ECMWF AND 00Z GFS AT LEAST
SIMILAR IN THEIR IDEAS (ALTHOUGH GFS IS MUCH SLOWER IN DEPARTING THE
LOW)...WILL FOLLOW THAT IDEA FOR NOW FOR POPS (CHANCE/LIKELY) AND
WIND (GUSTY NORTHWEST WINDS TO 30KTS ON FRIDAY NIGHT) FORECAST.
LATE ARRIVING 00Z ECMWF HAS BACKED AWAY FROM THE LOW PRESSURE SYSTEM
AND JUST KEEPING A BROAD SURFACE TROUGH MOVING THROUGH. BASED OFF
THE 12Z ECMWF ENSEMBLE MEMBERS...THAT DOESN/T SEEM TO UNREASONABLE.
SATURDAY SHOULD SEE A DIMINISHING OF BOTH OF THOSE AS THE LOW PULLS
OUT OF THE AREA AND A HIGH PRESSURE RIDGE MOVES IN FROM THE
SOUTHWEST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 122 AM EDT SUN SEP 28 2014
DRY AIR ASSOCIATED WITH HIGH PRES CENTERED OVER THE EASTERN GREAT
LAKES WILL CONTINUE TO BRING VFR CONDITIONS TO KIWD/KCMX/KSAW UNTIL
THIS EVENING. AS HAS BEEN THE CASE THE LAST FEW NIGHTS...SHALLOW
RADIATION FOG WILL DEVELOP AT NIGHT AND AFFECT KSAW. LOW-LEVEL WINDS
OVERNIGHT WILL HAVE MORE OF A DOWNSLOPE WESTERLY COMPONENT...SO AT THIS
POINT...NOT ANTICIPATING KSAW TO DROP BLO MVFR TOWARD DAYBREAK. A
COLD FRONT BOOSTED BY THE LAKE BREEZE WILL BRING VEERING WINDS LATE
THIS AFTERNOON AT CMX AND THIS EVENING AT SAW AND IWD. THERE IS SOME
UNCERTAINTY ON HOW QUICKLY THE FRONT WILL MOVE IN WITH LOWER MVFR
CLOUDS IN ITS WAKE. SOME SHOWERS MAY ALSO BE POSSIBLE ALONG THE LAKE
BREEZE BOUNDARY INTO N CNTRL UPPER MI LATE THIS AFTERNOON...BUT
CONFIDENCE ON ITS IMPACT AT SAW IS TOO LOW TO MENTION IN THE TAF.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 347 PM EDT SAT SEP 27 2014
LIGHT WINDS PERSIST THROUGH SUNDAY...THEN CHANGES ARE EXPECTED BY
MONDAY MORNING AS A FRONT WORKS NORTH TO SOUTH ACROSS LK SUPERIOR.
EXPECT WINDS TO SHIFT TO THE NORTHEAST AND QUICKLY RAMP UP TO 25-30
KTS AFTER MIDNIGHT SUNDAY NIGHT WITH STRONGER WINDS CONTINUING INTO
MIDDAY MONDAY. WINDS WILL DIMINISH MONDAY NIGHT INTO TUESDAY AS HIGH
PRESSURE SETTLES OVERHEAD. SOUTHEAST TO SOUTH WINDS INCREASE
WEDNESDAY INTO THURSDAY AHEAD OF THE NEXT LOW PRESSURE SYSTEM. WINDS
WILL BE STRONGEST OVER EASTERN HALF OF LK SUPERIOR. WHILE THERE IS
STILL UNCERTAINTY IN TIMING...AN EXTENDED NW GALE EVENT WILL BE
POSSIBLE SOMETIME FRIDAY INTO SATURDAY MORNING.
WITH MORE MOIST AIR BEGINNING TO WORK NORTH OVER LAKE SUPERIOR...
THERE IS THE POTENTIAL FOR PATCHY/AREAS OF FOG OVER MAINLY NORTHERN
PORTIONS OF LAKE SUPERIOR LATER TONIGHT THROUGH SUNDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
124 AM EDT SUN SEP 28 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 347 PM EDT SAT SEP 27 2014
...ONE MORE UNSEASONABLY WARM DAY IN STORE FOR SUNDAY...
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A STRONG RIDGE OVER MUCH
OF THE E HALF OF THE CONUS. 585-588 DECAMETER 5H HIGHS OVER THE UPPER
GREAT LAKES HAVE RESULTED IN INLAND HIGH TEMPS IN THE UPPER 70S TO
LOWER 80S ACROSS MUCH OF THE FORECAST AREA THIS AFTERNOON UNDER
MOSTLY SUNNY SKIES.
ANOTHER QUIET/CLEAR NIGHT IS EXPECTED TONIGHT UNDER THE INFLUENCE OF
THE HIGH PRESSURE RIDGE. MIN TEMPS SHOULD BE A LITTLE BIT HIGHER
THAN SATURDAY MORNINGS MINS DUE TO SOME INCREASE IN PRECIPITABLE
WATER. EXPECT MORE SHALLOW FOG FORMATION MAINLY WELL INLAND FROM
LAKE SUPERIOR. DOWNSLOPING SOUTHERLY WIND AND ASSOC MIXING SHOULD
GENERALLY PROHIBIT FOG FORMATION NEAR LAKE SUPERIOR.
EXPECT ONE MORE UNSEASONABLY WARM DAY ON SUNDAY. MIXING 850 MB OF
13-14C TO SFC SHOULD AGAIN YIELD HIGH TEMPS MAINLY IN THE UPPER 70S
AND LOWER 80S. ONSHORE SOUTH WINDS WILL RESULT IN COOLER TEMPS
AROUND 70S ALONG THE LAKE MI SHORELINE. KEPT IN SLIGHT CHC POPS FOR
SHRA OVER THE NCNTRL FCST AREA WHERE MODELS HINT THAT DEVELOPMENT OF
LAKE BREEZE OFF LAKE BREEZE COULD PROVIDE FOCUS FOR ISOLD
CONVECTION. MODIFIED NAM SOUNDINGS FOR 78/58 YIELD SBCAPE 200-300
J/KG WITH MINIMAL CIN.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 347 PM EDT SAT SEP 27 2014
A MORE ACTIVE AND TYPICAL FALL PATTERN WILL AFFECT THE AREA THROUGH
THE UPCOMING WEEK...WITH SIGNIFICANTLY COOLER WEATHER FOR MONDAY AND
EARLY NEXT WEEKEND.
SUNDAY NIGHT AND MONDAY...A SHORTWAVE TROUGH OVER MANITOBA WILL BE
INTERACTING WITH A RESIDUAL SFC TROUGH/COLD FRONT STRETCHING FROM
NORTH DAKOTA TO JUST NORTH OF LAKE SUPERIOR SUNDAY EVENING. MODEL
GUIDANCE HAD BEEN RATHER INCONSISTENT WITH THE STRENGTH AND TIMING
OF THE FRONT OVER THE PAST COUPLE DAYS...BUT SOME OF THE 12Z RUNS
TODAY APPEAR TO BE CONVERGING ON A SOLUTION. THE RECENT NAM AND GEM
RUNS ARE ADVERTISING A SHARPER TROUGH AXIS AND QUICKER PASSAGE MORE
IN LINE WITH THE ECMWF OVER THE PAST COUPLE DAYS. HAD ORIGINALLY
THOUGHT GUIDANCE WAS TRENDING SLOWER WITH YESTERDAYS RUNS...BUT AM
NOW MORE CONVINCED OF THE FASTER SOLUTION GIVEN THE ECMWF
PERSISTENCE. FRONTAL PASSAGE TIME LOOKS TO BE AROUND 00Z MONDAY
ALONG LAKE SUPERIOR. THE FRONT WILL CONTINUE SOUTHWARD THROUGH THE
NIGHT...CLEARING THE SOUTH CENTRAL AND EAST CWA SHORTLY AFTER 12Z
MONDAY.
ACTIVE LOW-LEVEL FGEN COMBINED WITH THE SHARP TROUGH AXIS WILL ALLOW
FOR DECENT PRECIP COVERAGE ALONG THE FRONT. THE ONE LIMITING FACTOR
TO MORE WIDESPREAD COVERAGE WILL BE LESSENING UPPER-LEVEL SUPPORT AS
THE RIGHT-ENTRANCE OF THE JET SHIFTS EASTWARD. THIS WILL KEEP THE
BEST COVERAGE ACROSS EASTERN LAKE SUPERIOR AND UPPER MI. ONLY MADE
SOME SMALL CHANGES TO THE POPS FOR MONDAY...KEEPING LIKELY POPS
CONFINED TO MAINLY THE NORTHEAST HALF OF THE CWA. IN THE MORNING AND
ALONG NE UPSLOPE AREAS OF LAKE SUPERIOR. BLUSTERY NE WINDS WILL
COMMENCE BEHIND THE FRONT ACROSS THE NORTH HALF. HIGHS TEMPS MONDAY
WILL BE IN THE MORNING FOR MUCH OF THE CWA....WITH TEMPS NORTHWEST
IN THE 40S AND SOUTHEST IN THE 50S BY THE AFTERNOON.
MONDAY NIGHT THROUGH TUESDAY NIGHT...THE FRONTAL PRECIP WILL CLEAR
THE CWA BY MONDAY EVENING WHILE MID-LEVEL RIDHING SHIFT ACROSS THE
UPPER GREAT LAKES AND A SFC HIGH BUILDS ACROSS NORTHERN ONTARIO AND
QUEBEC. THE AREA SHOULD REMAIN SOCKED IN WITH LOW CLOUDS THROUGH THE
NIGHT GIVEN PLENTY OF RESIDUAL LOW-LEVEL MOISTURE AND A DECENT
SUBSIDENCE INVERSION. CONTINUED NE UPSLOPE FLOW COMBINED WITH THE
MOISTURE WILL RESULT IN LINGER SHOWERS/DRIZZLE CENTRAL AND EAST
ALONG LAKE SUPERIOR THROUGH THE NIGHT. HOW LONG IT TAKES TO RID
THESE CLOUDS ON TUESDAY IS IN QUESTION. MORNING INVERSION
HEIGHTS OF 2-3KFT WILL TRAP REMAINING LOW-LEVEL MOISTURE BEFORE
MIXING AND THE ARRIVAL OF SOMEWHAT DRIER LOW-LEVEL AIR HELP ERODE
CLOUDS THROUGHOUT THE DAY. CLOUDS WOULD LIKELY REMAIN ACROSS THE
EAST LONGER GIVEN THE CLOSER PROXIMITY TO MOIST NE FLOW FROM THE
MOISTURE POOL.
WEDNESDAY THROUGH THURSDAY...DEEP TROUGHING OVER THE ROCKIES WILL BE
SHIFTING NORTHEASTWARD ACROSS THE NORTHERN PLAINS BY WEDNESDAY. A
LEAD SHORTWAVE WILL BE TRACKING ACROSS MANITOBA AS AN ASSOCIATED SFC
LOW SEND A COLD FRONT EASTWARD ACROSS THE UPPER MS VALLEY. THE FRONT
WILL BE ON THE DOORSTEP OF THE WESTERN CWA 12Z WEDNESDAY. WITH THE
MID-LEVEL RIDGE STILL OVER THE LOWER GREAT LAKES...INITIAL MID AND
UPPER-LEVEL SUPPORT WILL BE MARGINAL. THEREFORE...PRECIP COVERAGE
SHOULD BE MINIMAL WITH THE FRONT ON WEDNESDAY.
A QUICK-MOVING SHORTWAVE OVER BRITISH COLUMBIA WEDNESDAY WILL
REINFORCE THE DEEP TROUGH OVER THE NORTHERN PLAINS. COMBINED WITH
THE APPROACH OF THE RIGHT ENTRANCE OF AN UPPER JET AND INCREASING
LOW TO MID-LEVEL FGEN...THIS SHOULD ALLOW FOR A SUBSTANTIAL INCREASE
IN PRECIP COVERAGE ON THURSDAY AND THURSDAY NIGHT. THE ECMWF IS A
TOUCH SLOWER WITH THE TROUGH AND MORE WIDESPREAD WITH PRECIP THAN
THE GFS...BUT CONFIDENCE IS HIGH ENOUGH TO INTRODUCE LIKELY POPS
ACROSS THE WEST HALF THURSDAY AND THE EAST HALF THURSDAY NIGHT.
THURSDAY NIGHT THROUGH SATURDAY...MODEL SOLUTIONS DIVERGE AFTER
THURSDAY NIGHT AS THE GFS FORMS A STRONG LOW OVER LAKE HURON WHILE
THE ECMWF FORMS THE LOW CLOSER TO HUDSON BAY. EITHER WAY...THE
OVERALL PICTURE IS A SERIES OF RAW...CHILLY FALL DAYS BEGINNING ON
FRIDAY WITH BLUSTERY NW WINDS AND PLENTY OF WRAP-AROUND MOISTURE
BEHIND THE SYSTEM TO THE EAST. IN ADDITION...THE MID-LEVEL TROUGH
AXIS WILL REMAIN WEST OF THE AREA THROUGH FRIDAY...SO HAVE INCREASED
PRECIP CHANCES FOR FRIDAY. THIS IS ESPECIALLY TRUE ALONG LAKE
SUPERIOR WITH INCREASED LAKE MOISTURE AND UPSLOPE SUPPORT. THE
ARRIVAL OF 850 HPA TEMPS OF -3 TO -1C WILL SUPPORT SOME LAKE EFFECT
RAIN SHOWERS AS SFC-H8 DELTA T VALUES INCREASE TO AROUND 10C. THE
COOLEST WIDESPREAD TEMPS OF THE SEASON ARE ALSO EXPECTED AS HIGHS
STRUGGLE TO GET OUT OF THE 40S...A STARK DIFFERENCE FROM HIGHS IN
THE 70S THIS SATURDAY/TODAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 122 AM EDT SUN SEP 28 2014
DRY AIR ASSOCIATED WITH HIGH PRES CENTERED OVER THE EASTERN GREAT
LAKES WILL CONTINUE TO BRING VFR CONDITIONS TO KIWD/KCMX/KSAW UNTIL
THIS EVENING. AS HAS BEEN THE CASE THE LAST FEW NIGHTS...SHALLOW
RADIATION FOG WILL DEVELOP AT NIGHT AND AFFECT KSAW. LOW-LEVEL WINDS
OVERNIGHT WILL HAVE MORE OF A DOWNSLOPE WESTERLY COMPONENT...SO AT THIS
POINT...NOT ANTICIPATING KSAW TO DROP BLO MVFR TOWARD DAYBREAK. A
COLD FRONT BOOSTED BY THE LAKE BREEZE WILL BRING VEERING WINDS LATE
THIS AFTERNOON AT CMX AND THIS EVENING AT SAW AND IWD. THERE IS SOME
UNCERTAINTY ON HOW QUICKLY THE FRONT WILL MOVE IN WITH LOWER MVFR
CLOUDS IN ITS WAKE. SOME SHOWERS MAY ALSO BE POSSIBLE ALONG THE LAKE
BREEZE BOUNDARY INTO N CNTRL UPPER MI LATE THIS AFTERNOON...BUT
CONFIDENCE ON ITS IMPACT AT SAW IS TOO LOW TO MENTION IN THE TAF.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 347 PM EDT SAT SEP 27 2014
LIGHT WINDS PERSIST THROUGH SUNDAY...THEN CHANGES ARE EXPECTED BY
MONDAY MORNING AS A FRONT WORKS NORTH TO SOUTH ACROSS LK SUPERIOR.
EXPECT WINDS TO SHIFT TO THE NORTHEAST AND QUICKLY RAMP UP TO 25-30
KTS AFTER MIDNIGHT SUNDAY NIGHT WITH STRONGER WINDS CONTINUING INTO
MIDDAY MONDAY. WINDS WILL DIMINISH MONDAY NIGHT INTO TUESDAY AS HIGH
PRESSURE SETTLES OVERHEAD. SOUTHEAST TO SOUTH WINDS INCREASE
WEDNESDAY INTO THURSDAY AHEAD OF THE NEXT LOW PRESSURE SYSTEM. WINDS
WILL BE STRONGEST OVER EASTERN HALF OF LK SUPERIOR. WHILE THERE IS
STILL UNCERTAINTY IN TIMING...AN EXTENDED NW GALE EVENT WILL BE
POSSIBLE SOMETIME FRIDAY INTO SATURDAY MORNING.
WITH MORE MOIST AIR BEGINNING TO WORK NORTH OVER LAKE SUPERIOR...
THERE IS THE POTENTIAL FOR PATCHY/AREAS OF FOG OVER MAINLY NORTHERN
PORTIONS OF LAKE SUPERIOR LATER TONIGHT THROUGH SUNDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KLUBER
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1230 AM CDT SUN SEP 28 2014
.SYNOPSIS...
ISSUED AT 310 PM CDT SAT SEP 27 2014
AT 19Z...WATER VAPOR IMAGERY SHOWED A DEEP TROUGH OVER THE WEST
COAST WITH A CLOSED LOW CENTERED OVER CENTRAL CALIFORNIA. MOISTURE
STREAMED NORTHWARD ON THE DOWNSTREAM SIDE OF THE TROUGH WHERE LOTS
OF CLOUD COVER AND THUNDERSTORMS WERE OBSERVED FROM ARIZONA INTO
MONTANA. STRONG RIDGING WAS IN PLACE ACROSS THE REMAINDER OF THE
COUNTRY WHILE A CUTOFF UPPER LOW SPUN OVER WESTERN IOWA.
TEMPERATURES ACROSS THE PLAINS HAVE SOARED TO WELL ABOVE NORMAL
LEVELS AS WARM AIR STREAMS NORTH UNDER THE RIDGE. BY EARLY
AFTERNOON...READINGS IN THE LOW TO MID 80S WERE COMMON FOR MUCH OF
THE DAKOTAS THROUGH THE SOUTHERN PLAINS...WITH LOCAL AREAS RANGING
FROM 80 TO 85 DEGREES.
SLIGHTLY COOLER AIR ALOFT WAS OBSERVED FROM THE VICINITY OF THE IOWA
UPPER LOW DOWN INTO TEXAS. THIS LED TO STEEPER LAPSE RATES...AND
THEREFORE HAVE OBSERVED DECENT CUMULUS FIELD DEVELOP THIS
AFTERNOON.
THE UPPER LEVEL LOW ACROSS CA/NV THIS AFTN WILL LIFT THROUGH THE
ROCKIES AND INTO THE NRN PLAINS BY TUESDAY. A STRONG PACIFIC FRONT
WILL SWEEP THE FCST AREA MONDAY NIGHT AND TUESDAY PRODUCING HEAVY
RAIN ACROSS WRN NEB WITH LIGHTER AMOUNTS EAST. COOLER WEATHER
PREVAILS WEDNESDAY THROUGH SATURDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 310 PM CDT SAT SEP 27 2014
THE UPPER LOW OVER IOWA WILL STAY FAIRLY STATIONARY OR MAY EVEN
MEANDER WESTWARD SLIGHTLY TONIGHT. MODELS ARE SHOWING A WEAK IMPULSE
OF ENERGY ROTATING AROUND THE LOW...WHICH WOULD MOVE ACROSS THE
NORTHEAST PART OF THE FORECAST AREA AFTER 06Z TONIGHT. AT THE SAME
TIME...IT IS PROJECTED THAT THE LOW LEVEL JET WILL BE VEERING TO THE
NORTHEAST INTO THIS SAME AREA WHICH COULD BRING ENOUGH LIFT TO
DEVELOP SOME SHOWERS LATE TONIGHT AND EARLY SUNDAY MORNING.
TIME-FRAME LOOKS TO BE 09Z TO 15Z CURRENTLY. BELIEVE THERE WILL BE
DEVELOPMENT IN A NORTH TO SOUTH LINE SOMEWHERE FROM NORTH CENTRAL
INTO CENTRAL NEBRASKA. CONFIDENCE ISN/T REAL HIGH THOUGH IN
PLACEMENT AND AS COVERAGE WILL LIKELY BE ISOLATED TO
SCATTERED...HAVE SLIGHT CHANCES FOR SHOWERS IN THE FORECAST
CURRENTLY.
ALSO LOOKING AT POTENTIAL FOR FOG TONIGHT OVER THE WESTERN PART OF
THE FORECAST AREA. THE NAM IS HIGHLIGHTING A STRONG INCREASE IN LOW
LEVEL MOISTURE MAINLY WEST OF HIGHWAY 83 WHILE THE GFS IS FURTHER
EAST. THAT BEING SAID...THE RAP KEEPS MINIMAL LOW LEVEL MOISTURE
OVER THE LOCAL AREA...AS IT KEEPS THE POTENTIAL BETTER OVER WESTERN
KANSAS. THESE DIFFERENCES MAINLY RELY ON THE PLACEMENT OF THE
SURFACE LOW. WITH LOWER CONFIDENCE...HAVE NOT ADDED FOG INTO THE
FORECAST AT THIS TIME...BUT WILL PASS ON POTENTIAL TO ONCOMING
SHIFT.
LOOKING THEN INTO SUNDAY...WITH THE THOUGHT THAT ANY FOG AND/OR
CLOUD COVER THAT MAY LINGER INTO THE MORNING HOURS WILL QUICKLY
DISSIPATE...TEMPERATURES ALOFT WILL BE SIMILAR TO TODAY...AND WITH
DEEP MIXING EXPECTED...SHOULD ONCE AGAIN SEE HIGHS IN THE 80S.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 310 PM CDT SAT SEP 27 2014
SUNDAY NIGHT THROUGH TUESDAY...THE ECM AND NAM ARE THE SLOWEST SOLNS
WITH THE PASSAGE OF THE PACIFIC FRONT MONDAY NIGHT AND TUESDAY. THUS
RAIN CHANCES ARE DELAYED UNTIL EARLY MONDAY MORNING. IT IS POSSIBLE
THE FASTER AND STRONGER GFS/GEM SOLNS ARE A BETTER FCST BUT GIVEN
THE MODELS HAVE BEEN TRENDING SLOWER OVERALL...THE NAM/ECM APPEARS TO
BE THE BEST FIT.
A SOLID PV ANOMALY WILL BE APPROACHING THE FCST AREA MONDAY AFTN AND
THIS SHOULD PROVIDE AMPLE SUPPORT FOR SCATTERED TO NUMEROUS TSTMS
INTO THE EVENING. COLD AIR ALOFT AND PWS OVER 200 PERCENT OF NORMAL
ARE EXPECTED TO PRODUCE HEAVY RAIN...MAINLY ALONG AND WEST OF
HIGHWAY 61. THE NAM/ECM SOLN PRODUCES 1 TO 1.5 INCHES OF RAIN IN THE
WEST DOWN TO 1/4 INCH IN THE EAST. POPS ARE LIMITED TO THE LIKELY
CATEGORY FOR THIS FORECAST AS MODEL TIMING IS THE MAIN CONCERN FOR
THE FORECAST.
SOUTHEAST WINDS MONDAY INCREASE TO 25 MPH WITH GUSTS TO 35 MPH. THE
GFS/GEM MODELS SUGGEST 30 MPH WINDS GUSTING TO 40 MPH. THE MAX
TEMPERATURE FORECAST COOLS INTO THE UPPER 70S TO LOWER 80S. AN
INCREASE IN MID LEVEL CLOUDINESS IS EXPECTED WITH THE APPROACH OF
THE UPPER LOW.
SPC SUGGESTED AMPLE SHEAR WILL DEVELOP MONDAY AFTN AS SOUTHERLY
H500MB WINDS INCREASE TO 60 KT. THIS IS TRUE BUT COUPLED WITH THE
STRONG LOWER LEVEL SOUTHERLY WINDS...20 TO 30 KT...THE EFFECTIVE
SHEAR APPEARS WEAK NEAR 20 TO 30 KT AND THE NAM SOUNDINGS SUGGEST
NARROW CAPE. THE SIGNIFICANT SEVERE PARAMETER IN ALL SOLNS SEEMS TO
SUPPORT THE 5 PERCENT SEVERE WEATHER POTENTIAL MONDAY.
THE PACIFIC FRONT MOVES THROUGH THE FCST AREA TUESDAY. THE H500MB
COLD POOL CENTERED OVER SD SHOULD CONTINUE TO SUPPORT CONVECTION
ACROSS NRN NEB WITH HIGHS IN THE 60S TO LOWER 70S. THE 500M AGL
WINDS IN THE GFS...ECM AND GEM INCREASE TO OVER 30 KT ACROSS NRN NEB
DURING THE AFTN WHICH WOULD SUPPORT A WIND ADVISORY. THE 12Z ECM HAS
TRENDED TOWARD THE DEEPER GFS/GEM LOW PRESSURE SYSTEM SOLN. THE
STRONG WINDS DEVELOP IN CONJUNCTION WITH THE PV ANOMALY AND H700MB
WINDS OF 45 TO 55 KT SHOWN IN THESE MODELS.
TUESDAY NIGHT THROUGH SATURDAY...STRONG COLD FRONTS MOVE THROUGH
WEDNESDAY NIGHT AND THURSDAY NIGHT. BOTH SUGGEST A CHANCE OF
SHOWERS. THE SECOND COLD FRONT SENDS H850MB TEMPERATURES TO NEAR 0C
FRIDAY MORNING. HIGHS FRIDAY RISE INTO JUST THE 50S TO LOWER 60S
WHICH WOULD SUPPORT FROST SATURDAY MORNING BUT THIS HIGH MOVES OFF
VERY QUICKLY AND WARM AIR RETURNS TO THE FCST AREA FRIDAY NIGHT.
OTHERWISE HIGHS RISE INTO THE 60S AND 70S EACH DAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1229 AM CDT SUN SEP 28 2014
VFR CONDITIONS EXPECTED TONIGHT AND TOMORROW. SOME LIGHT
RAINSHOWERS OR SPRINKLES MAY DEVELOP NEAR SUNRISE BETWEEN KBBW
AND KONL. MIFG OR BR IS ALSO POSSIBLE ALONG THE PLATTE RIVER
VALLEY BETWEEN 2912Z AND 2914Z. SOUTHERLY WINDS WILL INCREASE
OVER WESTERN NEBRASKA SUNDAY AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BROOKS/CDC
SHORT TERM...BROOKS
LONG TERM...CDC
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS RALEIGH NC
332 AM EDT SUN SEP 28 2014
.SYNOPSIS...HIGH PRESSURE WILL EXTEND ACROSS THE MIDDLE ATLANTIC
STATES THROUGH TONIGHT. A WEAK AREA OF LOW PRESSURE WILL DEVELOP AND
TRACK ACROSS THE GULF COAST STATES MONDAY...THEN MOVE OFF THE
SOUTHEAST COAST MONDAY NIGHT AND TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM SUNDAY...
LOW-MID LEVEL RIDGE ALONG THE EAST COAST THIS MORNING...INCLUDING A
1023 MB SFC HIGH CENTERED OVER THE MIDDLE ATLANTIC STATES...WILL
DRIFT OFFSHORE TODAY. MEANWHILE...A MID-UPPER TROUGH OVER THE
CENTRAL CONUS...ONE COMPRISED OF A COUPLE OF WELL-DEFINED
CIRCULATIONS OVER IA AND EASTERN TX...WILL MOVE INITIALLY SLOWLY
EAST THIS MORNING THEN ACCELERATE EASTWARD LATER TODAY AND
TONIGHT...OWING TO THE APPROACH OF A KICKER TROUGH FROM SW CANADA.
THE NORTHERN EDGE OF AN AREA OF HIGH BASED STRATOCUMULUS (6-8
THOUSAND FT) ARCING FROM SE NC TO THE NC FOOTHILLS (JUST WEST OF THE
YADKIN) WILL PIVOT NORTHWESTWARD AND SPREAD - IN A THINNING/
SCATTERING STATE INTO THE SOUTHERN AND WESTERN PIEDMONT TODAY PER
THE 00Z GFS AND RECENT RAP RUNS...WHEREAS THE 00Z NAM APPEARED TOO
AGGRESSIVE/PESSIMISTIC WITH THESE SKY CONDITIONS PER COMPARISON TO
RECENT OBSERVATIONAL DATA. AS SUCH...THE NAM/S DEPICTION OF BKN TO
OVC 6-8 THOUSAND FT SKY COVERAGE OVER THE SOUTHERN AND WESTERN
PIEDMONT BY 18Z IS CONSIDERED AN OUTLIER AND WILL BE DISCOUNTED IN
FAVOR OF GENERALLY SCT COVERAGE AND ASSOCIATED PARTLY CLOUDY
CONDITIONS THROUGH THE BETTER PART OF THE AFTERNOON. THE REMAINDER
OF CENTRAL NC SHOULD REMAIN MOSTLY SUNNY...BENEATH PASSING CIRRUS
THAT WILL GRADUALLY THICKEN FROM THE WEST LATE IN THE DAY.
PROJECTED LOW LEVEL THICKNESS VALUES ABOUT 10 METERS HIGHER THAN
THOSE OF SATURDAY SUPPORT HIGHS IN THE UPPER 70S TO LOWER 80S...OR
ABOUT 3 DEGREES HIGHER THAN SATURDAY.
TONIGHT: NWP GUIDANCE IS RELATIVELY GOOD AGREEMENT REGARDING THE
APPROACH OF THE MID-UPPER TROUGH FROM THE WEST...WITH A CONSENSUS
POSITION OF THE PARENT UPPER LOW OVER THE LOWER OH VALLEY/NORTHERN
TN VALLEY BY 12Z MON. ASSOCIATED HEIGHT FALLS ALOFT...ON THE ORDER
30-50 METERS AT H5 OVERNIGHT...SHOULD SUPPORT THE NORTHEASTWARD
EXPANSION/DEVELOPMENT OF MID AND HIGH LEVEL/MIXED PHASE-GENERATED
RAIN. WITH CLOUD BASES EXPECTED TO HOLD AOA 10 THOUSAND FT...IT IS
LIKELY THAT ONLY VIRGA WILL FALL FROM THESE MID LEVEL CEILINGS...OR
AT PERHAPS A FEW SPRINKLES INVOF THE YADKIN RIVER AROUND DAYBREAK.
OTHERWISE...INITIALLY PARTLY TO MOSTLY CLEAR SKIES THIS EVENING OVER
THE NE PIEDMONT AND NORTHERN COASTAL PLAIN...AND DELAYED ARRIVAL OF
THE THICKER CLOUD COVER...GOOD RADIATIONAL COOLING CONDITIONS. LOWS
THERE ARE LIKELY TO DIP INTO THE MID-UPPER 50S...RANGING TO LOWER-
MIDDLE 60S OVER THE SOUTHERN PIEDMONT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 315 AM SUNDAY...
SHORTWAVE EXTENDING FROM THE OHIO VALLEY TO THE MISSISSIPPI VALLEY
MONDAY MORNING... WITH A WEAK SURFACE LOW DEVELOPING OVER GA/FL.
THIS IS FURTHER SOUTH THAN PREVIOUS MODEL RUNS. TAIL END OF THE
UPPER JET EXTENDING SOUTHWARD FROM NEW ENGLAND WILL PROVIDE UPPER
LEVEL SUPPORT FOR WIDESPREAD LIFT... HOWEVER GIVEN THE POSITION OF
THE LOW FURTHER SOUTH... MOISTURE TRANSPORT LOOKS LIMITED. HAVE
SCALED BACK QPF TO UNDER A HALF INCH ACROSS THE AREA... LOWER
AMOUNTS CLOSER TO THE VA BORDER.
SHORTWAVE WILL BE APPROACHING THE COAST TUESDAY MORNING... AS THE
SURFACE LOW MOVES NORTHEAST ALONG THE COAST. PRECIP WILL DIMINISH AS
SUBSIDENCE AND MIDLEVEL DRYING FOLLOWS... HOWEVER LINGERING LOW
LEVEL MOISTURE MAY BE SUFFICIENT TO PRODUCE SOME PATCHY LIGHT
RAIN/DRIZZLE IN TO WEDNESDAY. WEAK COLD AIR DAMMING WILL ALSO
PROLONG LOW LEVEL CLOUD COVER IN TO EARLY WEDNESDAY. PARENT HIGH
REMAINS FAR TO THE NORTH OVER QUEBEC... UNFAVORABLY POSITIONED FOR A
PROLONGED DAMMING EVENT... AND ANY REMAINING WEDGE WILL ERODE DURING
THE DAY. HIGH TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THIS
TIME.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 318 AM SUNDAY...
HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH THURSDAY... AS A
STRONG TROUGH APPROACHES FROM THE WEST. HIGH TEMPERATURES WILL TREND
TOWARD NORMAL THURSDAY AND FRIDAY AHEAD OF THIS SYSTEM. MODEL
AGREEMENT CONTINUES TO BE GOOD... WITH THE PARENT LOW MOVING NORTH
THROUGH THE GREAT LAKES AND THE ASSOCIATED COLD FRONT CROSSING THE
AREA FRIDAY NIGHT/EARLY SATURDAY. HIGH TEMPERATURES SATURDAY WILL
LIKELY BE DEPENDENT ON THE PASSAGE OF THIS FRONT.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 210 AM SUNDAY...
UNDER THE CONTINUED INFLUENCE OF MODIFIED CANADIAN HIGH PRESSURE
OVER THE MIDDLE ATLANTIC STATES...MAINLY VFR CONDITIONS WILL PREVAIL
THROUGH THE TAF PERIOD. THE EXCEPTION TO VFR WILL BE SHALLOW FOG AND
ASSOCIATED LIFR-MVFR VISIBILITY RESTRICTIONS AT KRWI/KRDU/KFAY...
LOWEST AND LONGEST AT KRWI. A BRIEF PERIOD OF MAINLY SCATTERED MVFR
RANGE CLOUD BASES MAY FOLLOW AS THE MOIST LAYER RISES AND DISPERSES
THROUGH 16Z AT KRWI AND KFAY. OTHERWISE...BENEATH PERIODS OF PASSING
CIRRUS...AN AREA OF 6-8 THOUSAND FT STRATOCUMULUS NEAR THE SC BORDER
THIS MORNING WILL SPREAD NORTH INTO CENTRAL NC TODAY...MOST NOTABLY
AT WESTERN TERMINALS WHERE ASSOCIATED CEILINGS COULD RESULT BY LATE
THIS AFTERNOON OR EVENING.
OUTLOOK: THE APPROACH OF AN UPPER LEVEL TROUGH FROM THE WEST WILL
CAUSE MID-HIGH CLOUDS TO THICKEN AND LOWER FROM WEST TO EAST LATE
TONIGHT...WITH PERHAPS A FEW SPRINKLES FROM MID LEVEL CLOUD BASES AT
TRIAD TERMINALS AROUND DAYBREAK MONDAY. A PERIOD OF MEASURABLE RAIN
AND CEILINGS LOWERING INTO MVFR RANGE WILL THEN BE POSSIBLE MON INTO
EARLY TUE...ESPECIALLY AT KFAY...AS SURFACE LOW PRESSURE SYSTEM
DEVELOPS AND TRACKS ACROSS THE GULF COAST (WELL SOUTH OF CENTRAL
NC). A SURGE IN NE LOW LEVEL FLOW IN THE WAKE OF THE LOW PRESSURE
SYSTEM MAY PRODUCE ANOTHER BRIEF PERIOD OF MVFR CEILINGS AT KRWI AND
KFAY ON WED.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...SEC
LONG TERM...SEC
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
142 AM EDT SUN SEP 28 2014
.SYNOPSIS...
HIGH PRESSURE ANCHORED NORTH OF THE AREA WILL BRING FAIR AND MILD
WEATHER TODAY THROUGH EARLY MONDAY. A WET FORECAST IS SHAPING UP
FOR LATE MONDAY AND TUESDAY AS A GULF LOW PRESSURE SYSTEM MOVES
ACROSS THE AREA. HIGH PRESSURE WILL BRING DRYING THROUGH MID-WEEK.
A STRONGER COLD FRONT MAY CROSS THE EAST COAST NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM SATURDAY...SOME TWEAKING OF SKY CONDITIONS FOR THIS
UPDATE. BASED ON LATEST SAT IMAGERY TRENDS...LOOKING AT MAINLY
HIGH AND SOME MID LEVEL CLOUDS FOR THE NC PORTION OVERNITE...
AND...ALL 3 DECKS FOR THE ILM SC PORTION OF THE CWA. WILL CONTINUE
WITH THE LOW CHANCE FOR -RA OR DRIZZLE FOR THE SC COUNTIES.
TWEAKED MINS A DEGREE OR 2 LOWER FOR THE ILM NC PORTIONS DUE TO
LESS CLOUDS...OTHERWISE NO EDITS NEEDED.
PREVIOUS DISCUSSION...................................
AS OF 730 PM SATURDAY...LATEST LOCAL KLTX AND 88D MOSAIC KEEPS THE
MAIN PCPN SHIELD SOUTH OF CAPE FEAR. LATEST HRRR MODEL KEEPS ANY
ONSHORE MOVEMENT OF THE PCPN ACROSS THE ILM SC COUNTIES. AS A
RESULT...HAVE ADJUSTED POPS KEEPING THEM AT LOW CHANCE TO AFFECT
MAINLY THOSE SC COUNTIES OVERNIGHT. CLOUDINESS HAS BEEN ADJUSTED
UPWARDS DUE TO ONGOING VARIABLY SKY CONDITIONS AND THE TRAPPED
MOISTURE BELOW 700 MB AS ADVERTISED BY VARIOUS MODEL TIME HEIGHT
DISPLAYS ACROSS THE FA. MIN TEMPS SLIGHTLY TWEAKED...TOWARDS THE
UPWARD SIDE DUE TO MORE CLOUDINESS AND THREAT OF PCPN.
PREVIOUS DISCUSSION...........................
AS OF 3 PM SATURDAY...HIGH PRESSURE CONTINUES TO WEDGE DOWN THE
COAST THIS AFTN...INTERACTING WITH A COASTAL TROUGH THAT SEEMS TO
BE EVER-PRESENT JUST OFFSHORE. WEAK LOW PRESSURE OFF THE
CHARLESTON, SC COAST WILL CONTINUE TO DROP WEAKLY TO THE SOUTH
TONIGHT AS HIGH PRESSURE BECOMES MORE DOMINANT.
AREAS OF SHOWERS ALONG THE COASTAL TROUGH HAVE BEEN TRYING TO PUSH
ONSHORE TODAY...DRIVEN BY THE E/NE FLOW BETWEEN THE SURFACE WEDGE
AND COASTAL TROUGH. THE MID-LEVELS OF THE COLUMN...THOSE ABOVE
750MB...ARE VERY DRY...AND THE CONTINENTAL AIR MASS IS DRIER THAN
THAT OFFSHORE. THIS IS PRECLUDING MOST OF THE SHOWER ACTIVITY FROM
MAKING IT ONSHORE...BUT CANNOT RULE OUT SOME ISOLATED LIGHT
SHOWERS THROUGH TONIGHT...FOCUSED ALONG THE COAST...WITH BEST
CHANCE ALONG THE GRAND STRAND AND DOWN TOWARDS THE SOUTH SANTEE
RIVER. THE NAM FORECAST PROFILES ARE HANDLING THE CLOUD COVER BEST
TODAY...SO USING THIS AS A GUIDE EXPECT LOW LEVEL CLOUDINESS TO
PERSIST INTO TONIGHT. AS THE HIGH BECOMES MORE STRONGLY ENTRENCHED
LOCALLY CLOUD COVER WILL WANE...BUT EXPECT ONCE AGAIN QUITE A BIT
OF STRATUS AROUND TONIGHT. THIS WILL LIMIT OVERALL COOLING AND
HAVE AGAIN SIDED WITH THE LAV NUMBERS...AND AM FORECASTING LOWS
AROUND 60 IN THE FAR WESTERN ZONES...TO NEAR 70 ALONG THE GRAND
STRAND.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SATURDAY...UPPER RIDGE OVER EASTERN CONUS BREAKS DOWN
THROUGH THE SHORT TERM AS A SERIES OF STRONG SHORT WAVES DROP
ACROSS NEW ENGLAND AND THE GREAT LAKES REGION. THE SURFACE PICTURE
IS A LITTLE MUDDLED DUE TO A WEAK PRESSURE PATTERN AND A
DIVERGENCE OF MODEL SOLUTIONS. HOWEVER...A CONSENSUS OF GUIDANCE
HAS A FRONTAL SYSTEM DRAPED ACROSS THE DEEP SOUTH ON SUNDAY
LIFTING NORTH ON MONDAY INTO COASTAL GEORGIA AND SOUTH CAROLINA.
INCREASING MOISTURE ADVECTION WILL MAKE FOR A CLOUDY MONDAY WITH
POPS STEADILY INCREASING FROM SLIGHT CHANCE IN THE MORNING TO
LIKELY OVERNIGHT. SUNDAY HOWEVER LOOKS TO BE A DECENT DAY WITH
MINIMAL CHANCES OF PRECIP AND A GOOD BIT OF SUN...ESPECIALLY EARLY
ON. DAYTIME HEATING WILL LIKELY POP A CU FIELD IN THE
AFTERNOON...AND THE CIRRUS SHIELD WILL STEADILY INCREASE IN
ADVANCE OF MONDAYS FRONTAL SYSTEM. TEMPERATURES WILL BE QUITE
SEASONAL THROUGH THE PERIOD.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 PM SATURDAY...FORECAST MODELS FOR THE MEDIUM RANGE ARE IN
DECENT AGREEMENT ON THE SYSTEM MOVING ACROSS THE SOUTHEAST DURING
THE FIRST COUPLE OF DAYS. BOTH THE GFS AND ECMWF OPERATIONAL
MODELS SHOW A RATHER LETHARGIC SHORTWAVE THAT WAVERS BETWEEN AN
OPEN WAVE AND CLOSED LOW. I HAVE MAINTAINED THE GOOD CHANCE OF
SHOWERS FOR THE FIRST PART OF TUESDAY TRENDING DOWN THEREAFTER.
THE AFOREMENTIONED OPERATIONAL MODELS DIVERGE WITH REGARDS TO THE
MID LEVEL PATTERN FOR THE REMAINDER OF THE PERIOD. THE GFS KEEPS A
WEAKNESS AROUND THE AREA...MUCH LIKE WE HAVE SEEN THIS WEEK WHILE
THE ECMWF HAS A MORE PROGRESSIVE SOLUTION. WPC FAVORS MORE
BLENDING WITH ECMWF SOLUTIONS SO I HAVE BACKED OFF THE SLIGHT
CHANCE POPS LINGERING INTO WEDNESDAY AND THURSDAY. BEYOND THIS...A
STRONG SHORTWAVE MOVING THROUGH THE OHIO VALLEY AND ATTENDANT COLD
FRONT MOVE ACROSS LATE FRIDAY AND SATURDAY. AT THIS POINT THE
FRONT LOOKS TO BE MOISTURE STARVED AND INTRODUCED LOWER CHANCE
POPS FOR THE NEW DAY OF THE FORECAST PERIOD...SATURDAY.
REGARDING TEMPERATURES...I GENERALLY ADDED A DEGREE OR TWO ACROSS
THE BOARD TO WPC GUIDANCE AS THE WESTERLY FLOW THAT IS FORECAST TO
DEVELOP SHOULD ALLOW A DOWNSLOPE COMPONENT TO WARRANT. HOWEVER
MOST VALUES ARE WITHIN A FEW DEGREES OF CLIMATOLOGY.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 06Z...-DZ/-RA POSSIBLE AT KCRE/KMYR OVERNIGHT AS WELL AS
LINGERING MVFR POSSIBLE...ESPECIALLY ALONG THE COAST...JUST BEFORE
DAYBREAK. OTHERWISE EXPECT VFR AS HIGH PRESSURE CONTINUES TO BUILD
ACROSS THE AREA WITH A WEAKENING COASTAL TROUGH OFFSHORE...WITH
ISOLATED SHOWERS ON SUNDAY.
LATEST RADAR DEPICTS A FEW LIGHT SHOWERS MOVING ACROSS KMYR/KCRE BUT
DO NOT EXPECT THIS TO CREATE ANY RESTRICTIONS. ANTICIPATE
POSSIBILITY OF MVFR DUE TO LOW CIGS OCCUR BEFORE DAYBREAK ALONG THE
COAST. OTHERWISE EXPECT VFR THROUGH THE OVERNIGHT HOURS WITH
NORTHEAST WINDS 5 TO 10 KTS. AFTER DAYBREAK...ANY MVFR DUE TO LOW
CIGS COULD LINGER INTO THE LATE MORNING HOURS...BUT CONDITIONS WILL
GRADUALLY IMPROVE TO VFR WITH PERSISTENT NORTHEAST WINDS. ISOLATED
SHOWERS ARE ANTICIPATED ACROSS MOST OF THE AREA THROUGHOUT THE DAY
AND INTO THE EVENING HOURS ON SUNDAY.
EXTENDED OUTLOOK...CHANCE OF SHOWERS/MVFR MONDAY AND TUESDAY AS LOW
PRESSURE MOVES ACROSS THE SOUTHEAST. MVFR/IFR CIGS ON WEDNESDAY/
POSSIBLY THURSDAY.
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM SATURDAY...SCEC ALL WATERS TO CONTINUE. TWEAKED
NE WINDS A KNOT OR 3 HIER BASED ON LATEST TRENDS AND 1ST LOOK AT
00Z GUIDANCE. SIG. SEAS TO RUN 3 TO 5 FT...EXCEPT A FOOT LOWER
SOUTH OF CAPE FEAR TO LITTLE RIVER INLET DUE TO THE SHADOW EFFECTS
FROM A NE WIND AND THE CONFIGURATION OF THE COASTLINE.
PREVIOUS DISCUSSION..................................
AS OF 730 PM SATURDAY...SCA WILL BE LOWERED TO SCEC FOR THE ILM NC
WATERS...AND A SCEC WILL REMAIN IN EFFECT FOR THE ILM SC WATERS.
THE SCEC FOR ALL WATERS WILL REMAIN IN EFFECT THRU MIDDAY SUNDAY.
MODESTLY TIGHTENED SFC PG ACROSS THE WATERS WILL PRODUCE NE 15 TO
OCCASIONALLY 20 KT OF WINDS OVERNIGHT. SIGNIFICANT SEAS WILL RUN 3
TO 5 FT...EXCEPT 2 TO 4 FT SOUTH OF CAPE FEAR TO LITTLE RIVER
INLET. DOMINANT PERIODS WILL RUN 5 TO 6 SECONDS. NOT MUCH OF ANY
GROUND SWELL TO SPEAK OF.
PREVIOUS DISCUSSION...........................
AS OF 3 PM SATURDAY...HIGH PRESSURE WEDGING DOWN THE COAST AND A
COASTAL TROUGH POSITIONED ABOUT 50 MILES OFFSHORE...CONTINUE TO
KEEP THE COASTAL WATERS PINCHED IN BETWEEN. THIS IS CREATING GUSTY
NE WINDS OF 15-25 KTS...AND SEAS OF 3 TO 6 FT THIS AFTN. A SLOW
DECREASE IN WIND SPEEDS IS EXPECTED TONIGHT AS THE HIGH PRESSURE
PUSHES FURTHER SOUTH...WEAKENING THE GRADIENT...BUT SPEEDS OF
10-20 KTS WILL REMAIN INTO SUNDAY MORNING. HOWEVER...THE SLIGHTLY
LOWER SPEEDS WILL ALLOW WAVE HEIGHTS TO DROP TO BELOW 6 FT...AND
THE SCA SHOULD BE ABLE TO EXPIRE AT 8PM FOR THE NORTHERN WATERS.
THEREAFTER...A SCEC MAY BE NEEDED FOR THE MUCH OF THE REST OF THE
NEAR TERM AS SEAS ARE FORECAST TO REMAIN 3-5 FT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...NORTHEAST WINDS OF 10 TO 15 KTS ON SUNDAY
WILL DECREASE TO AROUND 10 KTS OR LESS ON MONDAY AS OVERALL
PRESSURE GRADIENT SLACKENS. SEAS OF AROUND 3 FT ON SUNDAY WILL
DECREASE TO AROUND 2 FT ON MONDAY.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 3 PM SATURDAY...A MODEST NORTHEASTERLY FLOW WILL GREET
MARINERS TUESDAY MORNING ALONG WITH WIDESPREAD RAINFALL. WIND
SPEEDS WILL BE LIGHT INITIALLY...LESS THAN TEN KNOTS. AS WE
PROGRESS INTO EARLY WEDNESDAY...THE FLOW WILL BACK TO MORE OF A
DUE NORTHERLY DIRECTION AND INCREASE TO 10-15 KNOTS AS THE LOW
PRESSURE SYSTEM PULLS AWAY SLOWLY. BY THE END OF THE PERIOD WINDS
ARE BACK TO A NORTHEAST DIRECTION AS HIGH PRESSURE BUILDS DOWN
FROM THE CANADIAN MARITIMES. SIGNIFICANT SEAS SHOULD BE ON THE LOW
SIDE CITING THE LACK OF STRONG WINDS AND CHANGES IN THE
FETCH...GENERALLY 1-3 TO 2-4 FEET.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...COLBY
NEAR TERM...DOUGH
SHORT TERM...REK
LONG TERM...SHK
AVIATION...SGL/8
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
155 AM EDT SUN SEP 28 2014
.SYNOPSIS...
COOL HIGH PRESSURE WILL PERSIST ACROSS THE REGION TONIGHT AND WEAKEN
ON SUNDAY. A LOW PRESSURE SYSTEM WILL MOVE NORTHWARD FROM THE GULF
OF MEXICO SUNDAY NIGHT AND MONDAY AND SPREAD RAIN ACROSS THE REGION.
THE LOW SHOULD MOVE SLOWLY AWAY TO THE NORTHEAST MONDAY NIGHT AND
TUESDAY WITH COOL HIGH PRESSURE BUILDING IN FROM THE NORTHEAST ON
WEDNESDAY. A COLD FRONT WILL ARRIVE FROM THE NORTHWEST LATE IN THE
WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 150 AM...MID AND HIGH CLOUDS HAVE INCREASED ACROSS THE CWA
OVER THE PAST TWO HOURS. I WILL PRIMARILY UPDATE TO ADJUST SKY GRIDS
TO RECENT OBS AND TRENDS. IN ADDITION...I WILL DROP POPS TO ZERO
THROUGH THE REST OF TONIGHT.
AS OF 1030 PM EDT SATURDAY...LATEST GUIDANCE SEEMS TO AGREE WELL
WITH OBSERVED TEMPERATURE TRENDS ACROSS THE NORTHWEST NC PIEDMONT
AND NORTHERN NC MOUNTAINS WHERE CLEAR SKIES HAVE ALLOWED FOR BETTER
RADIATIONAL COOLING. THUS...TWEAKED MINIMUM TEMPERATURES ACROSS THE
REGION BY BLENDING IN LATEST ADJMAV WHICH YIELDED SLIGHTLY LOWER
MINS THROUGH THE ABOVE MENTIONED ZONES. THIS MODIFICATION ALSO
REINFORCED WARMER TEMPERATURES ACROSS THE REMAINDER OF THE REGION
WHERE COOLING HAS BEEN STUNTED SOMEWHAT. FORECAST REMAINS ON TRACK
REGARDING INCREASING CLOUDINESS FROM THE SOUTHEAST OVERNIGHT AS
MOIST UPGLIDE REGIME ENHANCES. LASTLY...ALSO BLENDED IN LATEST HPC
QPF GUIDANCE THROUGH 00Z TUESDAY TO UPDATE CURRENT STORM TOTAL
PRECIPIATION AMOUNTS. HOWEVER THIS ACTION DID NOT LEND ITSELF TO
ANY SIGNIFICANT CHANGES.
PREVIOUS DISCUSSION...
AS OF 220 PM...DRY AIR CONTINUES TO MIX IN FROM THE NE ALIGNED IN A
PERSISTENT SFC WEDGE. THE MAJORITY OF HIGHER MOISTURE AND CLOUD
COVER HAS PUSHED OUT OF THE CWFA WITH LINGER BKN/OVC CONDS ACROSS
THE SW/RN ZONES. TEMPS WILL CONTINUE TO RISE A FEW MORE DEGREES
THROUGH MAX HEATING...REMAINING A CAT OR SO BELOW NORMAL.
A QUIET OVERNIGHT PERIOD IS IN STORE WITH A SUBTROPICAL HIGH
REMAINING OVER THE SE CONUS. RAP SOUNDINGS ARE SHOWING A DECOUPLED
ATMOS OVERNIGHT...ALLOWING MINS TO REACH NORMAL LEVELS NORTH AND A
COUPLE DEGREES ABOVE NORMAL SOUTH WITH LINGERING CLOUDS. THERE COULD
BE SOME MTN VALLEY FG DEVELOPING ARND SUNRISE...BUT TDDS WILL REMAIN
FAIRLY HIGH FOR MUCH OF A DENSE THREAT.
LOW TO MID LEVEL ATL MOISTURE BEGINS PUSHING IN EARLY SUN MORNING
AND THE SRN ZONES WILL SEE THE BEST CLOUD COVER AFT DAYBREAK. THE
NAM IS MORE AGGRESSIVE WITH THIS SCENARIO THAN THE GFS...WHICH KEEPS
THE DEEPER MOISTURE ALIGNED ALONG THE WEDGE BNDRY. SRN FA SOUNDINGS
SHOW NEARLY SATURATED COLUMNS BY THE AFTERNOON AS A WEAK COASTAL LOW
BEGINS ADVECTING GOM MOISTURE INTO THE REGION. STILL...THE MAIN FLOW
WILL BE ATL...WHICH WILL INSTIGATE GOOD MECH LIFT ACROSS THE SRN
ESCARPMENT...NE GA AND SW NC MTNS BY THE AFTERNOON. POPS WILL RISE
QUICKLY INTO THE HIGH CHANCE AND LOW/END LIKELY RANGE SUN AFTERNOON
ACROSS THE FAR WEST...HOWEVER PRECIP AMOUNTS WILL REMAIN FAIRLY LOW
THROUGH THE NRT PERIOD AS INSTABILITY REMAINS LOW KEEPING CONVEC
PRECIP WELL SOUTH. POPS WILL REMAIN NIL OUTSIDE THE MTNS AND SW/RN
ZONES. MAX TEMPS WILL FEATURE A SW/NE COOL/WARM GRADIENT DUE TO
CLOUD COVER AND DIFF HEATING.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
AS OF 245 PM SATURDAY...AN H5 SHORTWAVE WILL LIFT FROM THE GULF
COAST TO THE EXTREME SRN APPALACHIANS SUNDAY NIGHT AND MERGE WITH A
NRN STREAM SHORTWAVE SWINGING EAST THROUGH THE OH VALLEY. AT LOWER
LEVELS...AN INCREASINGLY MOIST SOUTHEAST UPSLOPE FLOW WILL SET UP
OVER THE FORECAST AREA SUNDAY NIGHT TO ALLOW PRECIPITATION TO BECOME
WIDESPREAD BY DAYBREAK MONDAY...ACROSS AT LEAST THE SW HALF OF THE
AREA. DEEP LAYER FORCING WILL THEN CROSS THE REGION MON WITH THE
MERGING UPPER WAVES AND PASSING UPPER LEVEL JET DIVERGENCE. AN 850
MB LOW CENTER WILL LIKELY RIDE NE THROUGH THE SOUTHEAST PART OF THE
FORECAST AREA...SETTING UP ADDITIONAL WEAK FRONTOGENESIS OVER THE
AREA. THESE FEATURES WILL BE VERY SLOW TO MOVE E OR NE TO THE COAST
MON NIGHT THROUGH TUE...WITH CONTINUED LIGHT PRECIPITATION WRAPPING
BACK OVER THE REGION ON THE W SIDE OF THE LOW.
THE MAIN LIMITING FACTORS FOR HEAVY QPF ARE A FAIRLY DRY BOUNDARY
LAYER IN THE NC PIEDMONT AT ONSET...AS WELL AS THE STRONG POTENTIAL
FOR GULF COASTAL CONVECTION AND CONVECTION NEAR A WEAK WEDGE
BOUNDARY IMPEDING THE INFLUX OF MOISTURE. SO..THE QUESTION IS NOT
WHETHER IT WILL RAIN...BUT HOW MUCH. THE 12Z GFS IS PRODUCING A
BULLSEYE OF NEARLY 6 INCHES ALONG THE INTERSTATE 85 CORRIDOR...BUT
IT FEATURES LITTLE TO NO GULF COASTAL CONVECTION. THIS SOLUTION
SEEMS UNLIKELY...AND THE FORECAST WILL CONTINUE TO LEAN HEAVILY ON A
MODEL BLEND WITH A HEAVY NOD TOWARD THE DRIER SREF MEAN AND LATEST
ECM QPF. IN ADDITION...WITH A WEAK SURFACE CAD LAYER PERSISTING OR
REDEVELOPING AS THE RAIN ARRIVES...INSTABILITY SHOULD BE LARGELY
SHUNTED SOUTH OF THE REGION FOR THE UPCOMING EVENT. WITH 850 TO 500
MB LAPSE RATES RATHER WEAK OVER THE SFC HIGH...RAINFALL RATES SHOULD
NOT BE HIGH ENOUGH TO SUPPORT FLASH FLOODING. DURATION RAINFALL
ALONG MAIN STEMS AND THE MOST FLOOD PRONE AREAS WILL NEED TO BE
MONITORED...BUT ANTECEDENT CONDITIONS ARE UNFAVORABLE FOR MUCH OF A
HYDRO THREAT GIVEN EXPECTED QPF/DURATION. STILL...AN HWO MENTION
SEEMS WARRANTED FOR AT LEAST THE HEAVY RAINFALL MONDAY. A SMALLER
THAN MOS DIURNAL RANGE ON TEMPS WILL BE FEATURED WITH CAD CONDITIONS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM EDT SAT...A WEAK UPPER RIDGING WILL BUILD IN FROM THE
WEST TUE NIGHT INTO WED AS A DEAMPLIFYING SHORTWAVE PUSHES OFF THE
ATLANTIC COAST. THE UPPER RIDGE AXIS SHOULD CROSS THE REGION
THU...WITH SWLY FLOW ALOFT SETTING UP BY FRI IN LIGHT OF A DEEP
UPPER TROUGH APPROACHING FROM THE CENTRAL CONUS. THIS TROUGH IS
EXPECTED TO MOVE ACROSS THE EASTERN STATES LATE SAT INTO SUN.
AT THE SURFACE...A SURFACE WEDGE WILL SET UP ACROSS THE REGION BY
TUE NIGHT AND PERSIST THROUGH THU...YIELDING CONSIDERABLE LLVL
CLOUDINESS AND COOL NE WINDS DURING THIS PERIOD. NE WINDS SHOULD
VEER TO THE SE BY THU NIGHT AS THE SURFACE RIDGE WEAKENS AND SHIFT
EAST WHILE AN ACTIVE COLD FRONT APPROACHES FROM THE MISSISSIPPI
VALLEY. BOTH THE NEW 12Z GFS/ECMWF AGREE THAT THE FRONT WILL REACH
THE SOUTHERN APPALACHIANS BY AROUND SAT 00Z AND OFF TO OUR EAST BY
AROUND 12Z SAT. THE THREAT FOR SEVERE WEATHER LOOKS MINIMAL GIVEN
THE LATE OF GOOD UPPER FORCING/BOUNCY. IN FACT...MODELS HAVE TRENDED
A BIT DRIER AS THE FRONT WEAKENS AS IT CROSS THE FORECAST AREA.
HENCE...HAVE INHERITED LOW END CHANCE POPS DURING THE FROPA.
CONDITIONS SHOULD DRY OUT BY SAT AFTERNOON AS THE FRONT PUSHES
OFFSHORE AND A COOL DRY HIGH PRESSURE BUILDS IN FROM THE NW.
TEMPERATURES WILL REMAIN 3-7 DEGREES BELOW NORMAL THROUGHOUT THE
MEDIUM RANGE PERIOD.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AT KCLT AND ELSEWHERE...A WEAK RIDGE OF SFC HIGH PRESSURE WILL
REMAIN ACROSS THE WESTERN CAROLINAS THROUGH THE 6Z TAF PERIOD. THIS
PATTERN WILL PROVIDE LIGHT NORTHEAST WINDS...PERIODS OF CALM
EXPECTED BEFORE SUNRISE. BASED ON RECENT SATELLITE TRENDS AND
GUIDANCE...I WILL INDICATE BKN CLOUDS WITH BASES BETWEEN 050-060 KFT
ALONG WITH CIRRUS. WIDESPREAD RAIN WILL LIKELY SPREAD SW TO NE AFTER
6Z MON.
OUTLOOK...HIGH LEVELS OF MOISTURE WILL RETURN FOR THE START OF THE
WORK WEEK ASSOCIATED WITH AN AREA OF UNSETTLE WEATHER MOVING NORTH
OUT OF THE GULF OF MEXICO. PERIODS OF CONTINUOUS MODERATE TO HEAVY
RAINFALL WILL AFFECT THE AREA MON/TUE PRODUCING CIG AND VSBY
RESTRICTIONS.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 93% HIGH 94% HIGH 100%
KAVL MED 68% HIGH 82% HIGH 97% HIGH 90%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 94% HIGH 100% HIGH 100%
KAND HIGH 98% HIGH 93% HIGH 96% HIGH 92%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...NED
SHORT TERM...HG
LONG TERM...JOH
AVIATION...NED
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1146 PM CDT SAT SEP 27 2014
.SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 242 PM CDT SAT SEP 27 2014
MAIN FORECAST CONCERNS THIS PERIOD...ANY SMALL -SHRA CHANCES EARLY
THIS EVENING...TEMPERATURES THRU THE PERIOD.
DATA ANALYSIS AT 18Z HAD BROAD HIGH PRESSURE CENTERED OVER THE
EASTERN GREAT LAKES WITH RIDGING INTO THE MID MS VALLEY. LEE LOW
PRESSURE WAS LOCATED OVER EASTERN CO WITH TROUGHING NORTHEAST TO A
LOW OVER NORTHERN ONT. BROAD SOUTHEAST TO SOUTHWEST LOW LEVEL FLOW
CONTINUED TO BRING SEASONABLY WARM AIR NORTHWARD INTO THE UPPER
MIDWEST...WITH EARLY AFTERNOON TEMPS IN THE MID 70S TO LOWER 80S
ACROSS MUCH OF MN/IA/WI...AROUND 10F ABOVE NORMAL. WV IMAGERY SHOWED
THE MID LEVEL LOW CENTERED OVER NORTHWEST IA. SHORTWAVE ROTATING
AROUND THE EAST SIDE OF THE LOW ACROSS NORTH-CENTRAL IA/SOUTH-
CENTRAL COMBINED WITH SOME WEAK INSTABILITY PRODUCING A FEW -SHRA
LIFTING NORTH NEAR THE MN/IA BORDER.
GFS WITH ITS USUAL 5F HIGH BIAS ON SFC DEW POINTS ACROSS THE MUCH OF
THE UPPER MIDWEST...OTHERWISE 27.12Z MODELS LOOK TO HAVE INITIALIZED
QUITE WELL. SOLUTIONS FOR TONIGHT THRU SUN NIGHT TREND SIMILAR TO
EACH OTHER AND THEIR PREVIOUS RUNS. OVERALL SHORT-TERM FCST
CONFIDENCE REMAINS GOOD THIS CYCLE.
WEAK MID LEVEL LOW OVER NORTHWEST IA REMAINS NEARLY STATIONARY
TONIGHT THEN WEAKENS FURTHER SUN AS IT FINALLY SUCCUMBS TO INCREASED
BUILDING/FORCING OF THE UPPER RIDGING AHEAD OF THE MUCH STRONGER MID
LEVEL LOW COMING ACROSS THE GREAT BASIN. BY LATE SUN LITTLE REMAINS
OF THE WEAK MID LEVEL LOW AS IT IS SHOVED EAST/SOUTH OF THE REGION
BY THE WESTERN CONUS TROUGHING AND A NORTHERN STREAM SHORTWAVE
DROPPING TOWARD LK SUPERIOR.
LITTLE FORCING WITH STATIONARY MID LEVEL LOW TONIGHT. ANY CAPE AXIS
IS WEST OF THE FCST AREA LATE THIS AFTERNOON/EARLY THIS EVENING AND
CAPE DEPENDENT ON MODEL SFC DEW POINTS IN THE 60-65F RANGE BEING
CORRECT. BASED ON SFC OBS...DEW POINTS ALONG/EAST OF I-35 MOSTLY IN
THE 55-60F RANGE...WITH ANY CAPE LOOKING TO QUICKLY WANE WITH LOSS
OF DIURNAL HEATING LATE THIS AFTERNOON/EARLY THIS EVENING. LEFT
TONIGHT DRY. MODEL SOUNDINGS SHOWING LIGHTER WINDS ABOVE THE
BOUNDARY LAYER TONIGHT. BOUNDARY LAYER GRADIENT WINDS A BIT LIGHTER
THAN THOSE OF LAST NIGHT AS WELL. WITH LITTLE CHANGE OF THE LOW
LEVEL AIRMASS ADDED PATCHY LATE NIGHT/EARLY MORNING RADIATIONAL FOG
MENTION TO ALL THE RIVER VALLEYS AND THE LOW LAYING AREAS OF CENTRAL
WI. MODELS DEVELOP 500-1000 J/KG MU/SB CAPE OVER THE AREA SUN
AFTERNOON...BUT AGAIN THIS BASED ON SFC DEW POINTS IN THE 60-65F
RANGE. WITH EVAPO-TRANSPIRATION CONTINUING TO WIND DOWN WITH
MATURING/SENESCING CROPS ACROSS THE REGION...MORE REALISTIC DEW
POINTS ARE IN THE MID/UPPER 50S AS THEY HAVE BEEN THE PAST FEW
DAYS...ESPECIALLY ACROSS WI CLOSER TO THE CENTER OF THE GREAT LAKES
SFC HIGH. EVEN WITH 60-65F DEW POINTS...MODEL SOUNDINGS SHOWING 50-
75 J/KG OF CIN SUN AFTERNOON. LITTLE IN THE WAY OF FORCING/LIFT/
CONVERGENCE SIGNALS SUN WITH A WEAK SFC RIDGE AXIS OVER THE AREA AND
ANY REMAINING ENERGY WITH THE WEAK MID LEVEL LOW/TROUGH PASSING WELL
SOUTHWEST OF THE FCST AREA AND LEFT SUNDAY DRY. WEAK SFC GRADIENTS
OVER THE AREA AGAIN SUN NIGHT AND MAY YET NEED MORE MENTION OF
PATCHY LATE NIGHT/EARLY MORNING VALLEY FOG INTO MON MORNING. WITH
THE RATHER TIGHT MODEL CONSENSUS...USED A BLEND OF THE GUIDANCE
LOWS/HIGHS FOR TONIGHT THRU SUN NIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 242 PM CDT SAT SEP 27 2014
FORECAST CONCERNS FOR MONDAY THROUGH TUE NIGHT...ANY SMALL -SHRA
CHANCES MON...SHRA/TSRA CHANCE SPREADING IN TUE NIGHT...TEMPERATURES
THRU THE PERIOD.
27.12Z MODELS REACHING A TIGHTER CONSENSUS AS THE NORTHERN STREAM
SHORTWAVE SLIDES SOUTHEAST ACROSS THE GREAT LAKES MON/MON EVENING.
TREND IS TOWARD SLOWER AND MORE OPEN WAVE OF THE EARLIER RUNS WITH
THIS FEATURE. CONSENSUS SLOWLY IMPROVING ON THE ROCKIES SHORTWAVE
ENERGY TO EJECT NORTH-NORTHEAST THRU THE CENTRAL/NORTHERN PLAINS MON
NIGHT-TUE NIGHT. TREND IS A BIT FASTER WITH THIS FEATURE LIFTING
NORTH AS MODELS TREND STRONGER ON THE SHORTWAVE ENERGY TO DIG INTO
THE NORTHERN/CENTRAL ROCKIES BEHIND IT TUE/TUE NIGHT. FCST
CONFIDENCE IN THE MON THRU TUE NIGHT PERIOD IS ON THE GOOD SIDE.
WITH THE SLOWER/WEAKER TREND OF THE SHORTWAVE TO DROP ACROSS THE
GREAT LAKES MON/MON EVENING...BULK OF THE UPPER LEVEL DYNAMICS/
FORCING PASS NORTHEAST OF THE FCST AREA. STILL SOME WEAK TO MDT 1000-
850MB FN CONVERGENCE AND WEAK MOISTURE TRANSPORT/THETA-E CONVERGENCE
TO PASS ACROSS THE NORTHEAST END OF THE FCST AREA MON WITH PW VALUES
OVER AN INCH. CONTINUED THE SMALL -SHRA CHANCES NORTHEAST OF I-94 ON
MON FOR NOW WHICH BLENDS WELL WITH NEIGHBORING GRIDS. SLOWER TREND
OF THE TROUGH/FRONT MEANS A SLOWER ARRIVAL OF THE POST FRONTAL LOW
LEVEL COLD ADVECTION AND ANOTHER WARM/ABOVE NORMAL DAY FOR MUCH OF
THE FCST AREA. RAISED MON HIGHS SOME 3 TO 5F ACROSS THE CENTRAL
PORTIONS OF THE FCST AREA...INTO THE MID/UPPER 70S. QUIET/GENERALLY
COOLER MON NIGHT/TUE AS CAN HIGH PRESSURE BEHIND THE FRONT NOSES
INTO THE AREA. COOLEST OF THE AIR OVER THE NORTHEAST END OF THE FCST
AREA MON NIGHT/TUE...WITH TEMPS CLOSER TO LATE SEPT NORMALS.
SLIGHTLY FASTER TREND OF THE ROCKIES TROUGH LIFTING NORTH THRU
PLAINS TUE/TUE NIGHT KEEPS IT AND THE LOWER LEVEL AND SURFACE
FEATURES/FORCING ON A BIT MORE WESTERLY TRACK AND SOME DELAY ON
THEIR ARRIVAL INTO THE FCST AREA TUE NIGHT. INCREASING/STRONGER
LOWER LEVEL THERMO-DYNAMIC FORCING AND MOISTURE TRANSPORT SPREADS
INTO MAINLY THE NORTHWEST HALF OF THE FCST AREA AFTER MIDNIGHT TUE
NIGHT. INSTABILITY REMAINS RATHER LIMITED TUE NIGHT BUT GIVEN
STRENGTH/DEPTH OF THE FORCING/LIFT SIGNAL...CONTINUED A SMALL TSRA
CHANCE ACROSS MAINLY THE NORTHWEST HALF OF THE FCST AREA LATER TUE
EVENING/OVERNIGHT. TRENDED TOWARD WARMER OF GUIDANCE HIGH MON
OTHERWISE USED A BLEND OF THE NUMERICAL GUIDANCE FOR LOWS/HIGHS
MON NIGHT THRU TUE NIGHT.
FOR WEDNESDAY THROUGH SATURDAY.../DAYS 4 TO 7/...
FORECAST CONCERNS THIS PERIOD...SHRA/TSRA CHANCES WED THRU THU...
LINGERING SHRA CHANCES FRI...COOLING TEMPERATURES.
GOOD CONSENSUS AMONG 27.00Z/27.12Z MODELS WED AS THE LEAD SHORTWAVE
ENERGY LIFTS FROM NEAR THE ND/MN/MAN BORDER NORTHWARD THRU MAN AND
THE NEXT ENERGY DIGS ACROSS WY. BETTER AGREEMENT WITH THE WY ENERGY
AS IT THEN HEADS TOWARD THE REGION WED NIGHT/THU...FAVORING A
COMPROMISE OF THE EARLIER RUNS ON STRENGTH/TIMING. IMPROVING
COMPROMISE CONSENSUS THU NIGHT/FRI FOR YET A THIRD STRONGER PIECE OF
ENERGY TO DROP INTO THE LONGWAVE TROUGH...DEEPENING IT OVER THE
UPPER MIDWEST FOR FRI/SAT. UPPER MIDWEST IS UNDER COOLER NORTHWEST
FLOW OR THE COOL TROUGH ALOFT FRI/SAT. FCST CONFIDENCE IS AVERAGE
TO GOOD WED THRU SAT.
SHORTWAVE TROUGH LIFTING INTO MAN WED PUSHES A ROUND OF LOWER LEVEL
THERMO-DYNAMIC FORCING/LIFT INTO MAINLY THE NORTHWEST 2/3 TO 3/4 OF
THE FCST AREA WED...BIT SLOWER THAN EARLIER MODEL RUNS. MOISTURE
AXIS WITH PW VALUES OF 1 TO 1.5 INCHES PUSHES INTO THE AREA BUT THE
CAPE AXIS GENERALLY REMAINS WEST OF THE FCST AREA WED. HIGHER
SHRA/TSRA CHANCES WED MAINLY OVER THE NORTHWEST 2/3 OF THE FCST
AREA. THE DEEPER/STRONGER LOWER LEVEL THERMO-DYNAMIC FORCING
TRANSLATES EAST ACROSS THE FCST AREA WED NIGHT/THU. THIS WITH
FALLING HGTS ALOFT AND SOME PV ADVECTION AHEAD OF THE SECONDARY
SHORTWAVE/MAIN TROUGH AXIS. CONSENSUS RAIN CHANCES IN THE 60-70
PERCENT RANGE FOR MUCH OF THE AREA WED NIGHT/THU WELL TRENDED FOR
NOW AND WILL LIKELY TREND TOWARD 80-100 PERCENT ONE OR BOTH OF
THESE PERIODS AS THEY APPROACH. CAPE PROGGED TO BE ON THE WEAK
SIDE WED NIGHT/THU BUT GIVEN THE STRENGTH/DEPTH OF THE FORCING/
LIFT SIGNAL WILL CONTINUE WITH SCT TSRA IN THE FCST GRIDS THESE
PERIODS. SFC-850MB FRONT/TROUGH SLIDES EAST OF THE AREA THU NIGHT
TAKING THE BULK OF THE LOWER LEVEL FORCING/MOISTURE WITH IT. DEEP
MID LEVEL TROUGHING/CYCLONIC FLOW WITH COOLER 850-500MB TEMPS
PROGGED OVER THE AREA FRI. COOLER TEMPS ALOFT COMBINED WITH
RESIDUAL 925-850MB MOISTURE PRODUCE WEAK CAPE FRI AFTERNOON. -SHRA
CHANCES FRI APPEAR REASONABLE. DRIER HIGH PRESSURE BUILDS IN SAT.
MODEL/ENSEMBLE CONSENSUS HIGHS/LOWS TRENDING COOLER AND BELOW
NORMAL BY FRI/SAT LOOK GOOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1146 PM CDT SAT SEP 27 2014
THE ONLY CONCERN AT THE TAF SITES REMAINS WITH THE POTENTIAL FOR
FOG OVERNIGHT. CONDITIONS APPEARS TO BE BECOMING MORE FAVORABLE AS
THE NIGHT GOES ON WITH TEMPERATURE/DEW POINT SPREADS NOW DOWN TO
5F AT 4Z. SURFACE WINDS ARE AT ABOUT 4KTS OUT OF THE SOUTHEAST
WHICH IS A FAVORABLE COLD AIR DRAINAGE WIND OFF OF THE LA CROSSE
RIVER BASIN. WINDS LOOK LIKE THEY WILL BE BELOW 10KTS ALL THE WAY
UP TO 10KFT BUT THERE REMAINS SOME HIGHER WINDS RIGHT AT THE
INVERSION. THE PAST FEW RAP SOUNDINGS HAVE ALSO BEEN SHOWING SOME
VERTICAL MOTIONS OCCURRING WHEN YOU WOULD PREFER TO HAVE MORE
SUBSIDENT AIR. THERE ISN/T ANY STRATUS SHOWING UP AT THE
MOMENT...SO EXPECT THAT IF THE FOG/STRATUS DOES FORM THAT IT WILL
BE CLOSER TO DAY BREAK. OTHERWISE...LIGHT WINDS AND CLEAR SKIES
WILL PREVAIL THROUGH SUNDAY EVENING ACROSS THE REGION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
955 AM EDT SUN SEP 28 2014
...LOCALLY HEAVY RAINFALL POSSIBLE INLAND AREAS THIS AFTERNOON AND
EVENING...
.UPDATE...SFC DATA SHOWS NELY FLOW CONTINUES OVER MOST OF THE
FORECAST AREA THOUGH PER JAX 12Z SOUNDING IT IS ONLY UP TO 1000
FT. DATA SUGGESTS THE WEAK FRONTAL BOUNDARY COULD BE LOCATED STILL
ACROSS OUR SRN ZONES LEADING TO A WEAK LOW PRES SYSTEM OFFSHORE OF
THE SE U.S. COAST NEAR 31N80W. WARM ADVECTION ATOP THE BOUNDARY
HAS LEAD TO EROSION OF STRATUS ALONG THE COAST BUT TEMPORARY
IMPROVEMENT IN SKY WILL BE SHORT-LIVED AS CUMULUS FORM IN THE
MOISTURE RICH AIRMASS.
VISIBLE IMAGERY SHOWS A MID LEVEL DISTURBANCE ALONG THE FL BIG
BEND AREA THAT IS SLOWLY SHIFTING NWD. THIS IN COMBINATION WITH
THE SLOWLY LIFTING WARM FRONT WILL LEAD TO ENHANCED RAIN CHANCES
BY LATE MORNING INTO THE AFTERNOON HOURS. HAVE ESSENTIALLY KEPT
THE CHANCE POPS ALONG THE COASTAL AREAS AND MAINTAINED LIKELY
CHANCES OVER INLAND AREAS. MAIN UPDATE CHANGE WAS TO CUT BACK ON
PRECIP CHANCES THIS MORNING A BIT BASED ON THE HRRR AND RADAR
TRENDS. INCLUDED LOCALLY HEAVY RAINFALL WORDING FOR INLAND AREAS
AS THE FRONT...DAYTIME HEATING AND HIGH MOISTURE (PWAT 2.12 INCHES
ON THE SOUNDING) AND SLOW STORM MOTION SUGGEST HIGH RAIN RATES
(E.G. 2 INCHES IN 30 MINUTES) WILL BE LIKELY IN SOME STORMS.
ANTICIPATE AT LEAST SCATTERED EVENING CONVECTION ESPECIALLY OVER
THE INTERIOR BEFORE GRADUALLY WANING OVERNIGHT. HIGH TEMPS TODAY
HELD IN CHECK BY MOSTLY CLOUDY SKIES...AND BELOW NORMAL AGAIN FOR
LATE SEP. HIGHS MAINLY AROUND 80 TO 85 EXPECTED...WITH SOME UPPER
80S POSSIBLE INLAND NE FL S OF LIVE OAK.
&&
.AVIATION...STRATUS LAYER ERODED AT CRG BUT CUMULUS WILL CONTINUE
THERE TODAY AROUND MVFR RANGE WITH OCNL VFR. OTHERWISE...STRATUS
IN THE IFR TO LOW END MVFR RANGE LIKELY TO CONTINUE THROUGH LATE
MORNING AND POSSIBLY EARLY AFTERNOON. A FEW SHOWERS POSSIBLE ALONG
THE COASTAL AREAS THROUGH 16Z...WITH SCATTERED COVERAGE ANTICIPATED
IN THE AFTN. MVFR CIGS ARE LIKELY TO PERSIST IN THE AFTERNOON WITH
SHOWERS AND TSTMS CHANCES INCREASING. BEST CHANCE OF TSTMS WILL BE
FOR GNV AND OCNL STORMS POSSIBLE THERE AROUND 19Z-23Z. LOW END
MVFR CONDITIONS FOR NOW IN TSTMS BUT IFR TSTMS POSSIBLE.
&&
.MARINE...NE TO E WINDS NEAR 10-15 KT WILL CONTINUE TODAY THEN
BEGIN TO COME AROUND TO MORE E AND THEN SE TONIGHT. SEAS ARE MAINLY
IN THE 3-5 FT RANGE AND BASED ON OBS TWEAKED SEAS UP IN THE FCST
AND GRIDS. OTHERWISE LITTLE CHANGE.
RIP CURRENTS: MODERATE RISK TODAY DUE TO LINGERING SEAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 85 71 83 69 / 50 50 70 60
SSI 81 72 80 72 / 40 40 70 70
JAX 85 72 84 71 / 50 50 70 60
SGJ 83 74 83 73 / 40 40 70 60
GNV 87 71 83 71 / 60 50 70 50
OCF 87 72 84 71 / 60 50 70 50
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
SHASHY/GUILLET
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
603 AM CDT SUN SEP 28 2014
...UPDATED AVIATION DISCUSSION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 215 AM CDT SUN SEP 28 2014
DURING THE SHORT TERM PERIOD, AN UPPER LEVEL RIDGE WILL SHIFT
EASTWARD ACROSS THE PLAINS TODAY INTO TOMORROW WITH AN UPPER LEVEL
SHORTWAVE MOVING FROM THE UPPER MISSISSIPPI VALLEY INTO THE OHIO
VALLEY. MEANWHILE, A LARGE UPPER LEVEL LOW WILL CONTINUE TO SPIN
ACROSS THE DESERT SOUTHWEST TODAY THEN SHIFT CLOSER TO THE FOUR
CORNERS REGION BY TOMORROW MORNING. MID TO UPPER LEVEL MOISTURE
WILL BE ON THE RISE AS THIS FEATURE APPROACHES WITH PARTLY CLOUDY
SKIES EXPECTED TODAY INTO TONIGHT. THIS FEATURE WILL ALSO ALLOW
EVEN FURTHER INTENSIFICATION OF THE LEE TROUGH ACROSS EASTERN
COLORADO WITH SOUTHERLY WINDS EXPECTED THROUGH TOMORROW MORNING.
BREEZY CONDITIONS ARE EXPECTED ONCE AGAIN THIS AFTERNOON AS THE
PRESSURE GRADIENT TIGHTENS DUE TO ATMOSPHERIC MIXING. HIGHS TODAY
ARE EXPECTED TO REACH INTO THE LOWER TO MID 80S WITH LOWS AROUND
60 DEGREES.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 309 AM CDT SUN SEP 28 2014
MODELS REMAIN IN GOOD AGREEMENT WITH AN UPPER LEVEL TROUGH
BECOMING NEGATIVELY TILTED AS IT EXITS THE ROCKIES AND MOVES
ACROSS THE CENTRAL HIGH PLAINS MONDAY NIGHT. AS THIS UPPER LEVEL
SYSTEM APPROACHES WESTERN KANSAS EARLY MONDAY A SURFACE TROUGH OF
LOW PRESSURE WILL DEEPEN ACROSS EASTERN COLORADO. SURFACE
DEWPOINTS WILL INCREASE INTO THE MID TO UPPER 50S ACROSS WESTERN
KANSAS BY LATE DAY AS GUSTY SOUTHEAST WINDS INCREASE INTO THE 25
TO 30 MPH RANGE. USING THE 00Z NAM AS A GUIDE IT CURRENTLY APPEARS
THE SURFACE TROUGH, BETTER INSTABILITY, AND 0-6KM SHEAR FROM 21Z
TO 03Z WILL BE NEAR OR WEST OF THE COLORADO BORDER. CONVECTION
THEN SPREADS EAST/NORTHEAST ACROSS WESTERN KANSAS DURING THE
OVERNIGHT HOURS AS THE UPPER LEVEL TROUGH LIFTS NORTHEAST. A FEW
STORMS EARLY IN THE EVENT NEAR THE COLORADO BORDER STILL APPEARS
TO HAVE THE POTENTIAL TO BE SEVERE GIVEN THE CAPE AND 0-6KM SHEAR
VALUES AT 00Z TUESDAY WITH STRONG WINDS AND MARGINAL SEVERE HAIL
BEING THE MAIN HAZARD.
THUNDERSTORMS WILL TAPER OFF FROM WEST TO EAST LATE MONDAY NIGHT
INTO EARLY TUESDAY AS THE UPPER LEVEL TROUGH LIFTS NORTHEAST INTO
NEBRASKA. A SURFACE TROUGH OF LOW PRESSURE BY TUESDAY AFTERNOON IS
FORECAST TO BE LOCATED FROM ROUGHLY HAYS TO MEADE WITH LOW LEVEL
MOISTURE STILL PRESENT EAST OF THIS SURFACE BOUNDARY. BY LATE
TUESDAY CAPE VALUES CLIMB TO NEAR 1500 J/KG OR GREATER NEAR AND
EAST OF THIS SURFACE BOUNDARY WITH 0-6KM SHEAR VALUES OF AROUND 40
KNOTS. IN ADDITION 850MB THTA-E ADVECTION IMPROVES NEAR THE NOSE
OF AN 850MB JET IN OR NEAR NORTH CENTRAL KANSAS TUESDAY EVENING.
AT THIS TIME THE NAM AND GFS DIFFER SOME ON WHERE THIS AXIS OF
BETTER INSTABILITY AND FORCING WILL BE LATE TUESDAY WITH THE NAM
FURTHER WEST. AS A RESULT CONFIDENCE IS NOT HIGH ON WHERE THIS
SURFACE BOUNDARY WILL BE LOCATED TUESDAY NIGHT SO WILL STAY
CLOSE TO THE PREVIOUS FORECAST WHICH APPEARS TO BE A NICE
CONSENSUS BETWEEN THE NAM AND GFS.
ANOTHER UPPER LEVEL TROUGH WILL APPROACH THE NORTHERN/CENTRAL
ROCKIES MID WEEK. AS THIS NEXT SYSTEM APPROACHES FROM THE
NORTHWEST A COLD FRONT WILL MOVE SOUTH ACROSS TO THE NORTHERN
PLAINS. ANOTHER CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE ACROSS WESTERN KANSAS LATE WEDNESDAY INTO THURSDAY AS
THIS NEXT SYSTEM CROSSES THE CENTRAL/NORTHERN PLAINS AND THE COLD
FRONT MOVES SOUTH ACROSS WESTERN KANSAS. IN ADDITION TO ANOTHER
CHANCE FOR PRECIPITATION SOME COOLER AIR IS EXPECTED LATE WEEK.
BEHIND THIS COLD FRONT HIGHS ON THURSDAY AND FRIDAY CURRENTLY
APPEARS TO BE MAINLY IN THE UPPER 60S TO LOWER 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 601 AM CDT SUN SEP 28 2014
06Z NAM BUFR SOUNDINGS AND LATEST HRRR INDICATING THE CHANCE FOR
SCATTERED CLOUDS IN THE 4000 TO 8000FT AGL LEVEL TODAY. LIGHT
SOUTHERLY WINDS WILL INCREASE BY LATE MORNING INTO THE 15 TO NEAR
20 KNOT RANGE. THE STRONGER WINDS THIS AFTERNOON WILL BE AT GCK.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 84 60 84 59 / 0 0 0 50
GCK 83 60 83 57 / 0 0 20 70
EHA 81 59 82 56 / 0 0 50 60
LBL 84 60 84 59 / 0 0 20 70
HYS 84 60 84 60 / 0 0 10 60
P28 86 61 87 63 / 0 0 0 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...HOVORKA_42
LONG TERM...BURGERT
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
742 AM EDT SUN SEP 28 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 603 AM EDT SUN SEP 28 2014
...ONE MORE UNSEASONABLY WARM DAY TODAY...AND QUITE LIKELY THE LAST
DAY WITH TEMPERATURES THIS HIGH FOR THE REST OF THE YEAR...
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...STRONG RIDGE THAT WAS
EXTENDING INTO NRN ONTARIO IS BEING SUPPRESSED BY SHORTWAVE TROF
THAT HAS BEEN MOVING ACROSS SOUTHERN CANADA. THIS TROF IS SUPPORTING
A SHARP COLD FRONT THAT CURRENTLY EXTENDS FROM SE ND TO JUST S OF
JAMES BAY. JUST BEHIND FRONT...TEMPS QUICKLY FALL OFF INTO THE 40S
AND 30S...GIVING AN IDEA OF THE DRAMATICALLY COLDER CONDITIONS THAT
WILL SWEEP INTO THE AREA FOR MON. MID LEVEL LOW THAT WAS CENTERED
ALONG THE IA/MO BORDER 24 HRS AGO HAS MOVED LITTLE...NOW OVER IA.
SCT/BKN MAINLY THIN HIGH CLOUDS TO THE NE OF THIS FEATURE HAVE
HELPED TO KEEP RADIATION FOG A LITTLE LESS WIDESPREAD AND LESS DENSE
EARLY THIS MORNING.
FCST SOUNDINGS SHOW LITTLE CHANGE IN TEMP PROFILE FROM YESTERDAY...
SO LARGELY UTILIZED YESTERDAYS MAX TEMPS AS A BASIS FOR TODAYS MAX
TEMPS. TEMP RISE THIS MORNING SHOULD ALSO FOLLOW A SIMILAR DIURNAL
CURVE TO WHAT OCCURRED YESTERDAY MORNING. PRETTY GOOD CHC RECORD
HIGH OF 77F FOR NWS KMQT SITE WILL FALL TODAY. SHARP COLD FRONT TO
THE N WILL DRIFT S TODAY AND SHOULD REACH THE KEWEENAW LATE IN THE
AFTN. AS IS CURRENTLY NOTED WITH FRONTAL BOUNDARY...PCPN WILL
CONTINUE TO OCCUR MOSTLY ON THE COLD SIDE OF THE SFC COLD FRONT AS
NICE FRONTOGENETICAL CIRCULATION UNDER RIGHT ENTRANCE OF UPPER JET
WILL CONTINUE TO SUPPORT PCPN ON THE COLD SIDE OF THE SFC FRONT.
THAT SAID...WEAK PRES GRADIENT AHEAD OF FRONT WILL ALLOW LAKE
BREEZES TO DEVELOP TODAY. WITH A FEW HUNDRED J/KG OF MLCAPE...LAKE
BREEZE MAY BE SUFFICIENT TO KICK OFF ISOLD SHRA THIS AFTN ACROSS
PORTIONS OF THE CNTRL AND ERN FCST AREA. MOST HIGH RES MODEL
GUIDANCE CONTINUES TO SHOW THIS POTENTIAL.
SFC COLD FRONT WILL CONTINUE TO DRIFT S TONIGHT WITH PCPN REMAINING
MOSTLY ON THE COLD SIDE OF THE BOUNDARY...SUPPORTED BY
FRONTOGENETICAL CIRCULATION AS DISCUSSED ABOVE. TRAILING SHORTWAVE
CURRENTLY OVER SCNTRL CANADA WILL DIG INTO THE UPPER GREAT LAKES
MON. WITH BEST OVERLAP OF FGEN AND DEEP LAYER FORCING FROM SHORTWAVE
PER QVECTORS PASSING JUST N AND E OF FCST AREA...HEAVIER/STEADIER
SHRA/RA SHOULD PASS N AND E OF THE AREA. HOWEVER...DECENT FORCING
STILL SUPPORTS LIKELY TO CATEGORICAL POPS SPREADING SE TO THE
KEWEENAW AFTER MIDNIGHT TONIGHT AND TO WRN AND NRN UPPER MI BY 12Z
MON.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 326 AM EDT SUN SEP 28 2014
MONDAY WILL BE A SIGNIFICANT CHANGE IN THE WEATHER FOR UPPER
MICHIGAN...AS A COLD FRONT SWEEPS SOUTHEAST ACROSS THE AREA LATE
SUNDAY NIGHT THROUGH MONDAY. AS THIS OCCURS...EXPECT A BAND OF
SHOWERS TO BE MOVING ACROSS THE AREA ALONG AND BEHIND THE SURFACE
COLD FRONT BEFORE SINKING SOUTHEAST OF THE AREA ON MONDAY EVENING.
EVEN AS A BULK OF THE RAIN HAS SHIFTED OVER THE SOUTHEAST HALF OF
THE CWA ON MONDAY AFTERNOON...STILL EXPECT PLENTY OF LOW CLOUDS AND
LIGHT RAIN/DRIZZLE OVER THE AREA...ESPECIALLY THOSE FAVORED BY
NORTH-NORTHEAST UPSLOPE WINDS. IN ADDITION...WITH 900MB TEMPS
AROUND -1C AND LAKE SUPERIOR TEMPS BETWEEN 6-12C WOULD EXPECT AT
LEAST SOME LAKE ENHANCEMENT FOR THE AREAS NEAR LAKE SUPERIOR. WITH
INVERSION HEIGHTS RUNNING AROUND 3-3.5KFT DON/T EXPECT THE RAIN TO
BE TOO HEAVY...BUT ENOUGH TO LEAD TO A PERSISTANT LIGHT RAIN. WILL
CONTINUE TO SHOW LIKELY TO DEFINITE POPS IN THE FAVORED WIND
DIRECTIONS NEAR LAKE SUPERIOR AND AT LEAST CHANCES ELSEWHERE INTO
THE EVENING HOURS ON MONDAY. MODELS THEN SHOWING INVERSION HEIGHTS
FALLING THROUGH THE NIGHT UNDER THE INCREASED SUBSIDENCE FROM THE
HIGH PRESSURE RIDGE (HIGH CENTERED IN NORTHEAST ONTARIO) MOVING INTO
THE AREA. THUS...WILL SHOW DECREASING POPS THROUGH THE NIGHT AND
EVENTUALLY CLOUD COVER THROUGH THE DAY ON TUESDAY INTO TUESDAY
NIGHT. THE COMBINATION OF THE RAIN WITH STIFF NORTH-NORTHEAST WINDS
(15-25KTS) AND AFTERNOON TEMPERATURES IN THE MID 40S (30-35
DEGREES COLDER THAN THIS AFTERNOON) OVER THE NORTH HALF WILL MAKE
FOR A SIGNIFICANTLY DIFFERENT DAY THAN WHAT HAS BEEN EXPERIENCED
OVER THE LAST SEVERAL DAYS.
AS THE U.P. FINALLY STARTS TO BREAK OUT OF THE CLOUDS FROM MONDAY/S
SYSTEM...THE NEXT UPPER TROUGH WILL BE WORKING TOWARDS THE AREA ON
TUESDAY NIGHT AND BRING THE NEXT PERIOD OF UNSETTLED WEATHER TO THE
AREA FOR WEDNESDAY AFTERNOON THROUGH SATURDAY. THIS PERIOD OF
UNSETTLED WEATHER WILL BE ASSOCIATED WITH THE UPPER TROUGH
CURRENTLY OVER THE WESTERN CONUS SHIFTING EAST THROUGH THE AREA
DURING THAT PERIOD. THE FIRST WAVE FROM THAT UPPER TROUGH WILL MOVE
INTO THE AREA ON WEDNESDAY AFTERNOON AHEAD OF A WARM FRONT LIFTING
NORTHEAST TOWARDS THE AREA FROM A LOW NEAR LAKE WINNIPEG. WILL SHOW
INCREASING POPS FROM SOUTHWEST TO NORTHEAST FOR WEDNESDAY AFTERNOON
INTO WEDNESDAY NIGHT...WITH THE HIGHEST POPS (LIKELY) RUNNING ALONG
THE COLD FRONT THAT WILL BE MOVING THROUGH WESTERN AND CENTRAL
UPPER MICHIGAN LATE WEDNESDAY NIGHT AND THURSDAY. AS THIS COLD
FRONT IS SLOWLY WORKING EAST ACROSS THE AREA...A STRONG SHORTWAVE
DIVING SOUTHEAST THROUGH THE UPPER TROUGH WILL POTENTIALLY LEAD TO
THE INTENSIFICATION OF A LOW IN THE MID MISSISSIPPI VALLEY ON
THURSDAY EVENING. THIS LOW WILL CONTINUE TO INTENSIFY AS IT LIFTS
NORTHEAST ACROSS UPPER MICHIGAN ON FRIDAY MORNING AND THEN
NORTH-NORTHEAST INTO CANADA. WILL CONTINUE LIKELY POPS AS THIS LOW
MOVES THROUGH...ALTHOUGH CONFIDENCE IN THE STRENGTH IS LIMITED DUE
TO THE VARYING SOLUTIONS SHOWN IN THE MODELS (NOT UNEXPECTED WITH
UPSTREAM PHASING OF STRONG SHORTWAVES). THE 12Z ECMWF ENSEMBLE
MEMBERS ARE NOT MUCH OF A HELP WITH AROUND HALF OF THEM NOT SHOWING
A LOW RIDING UP THE COLD FRONT. WITH 12Z ECMWF AND 00Z GFS AT LEAST
SIMILAR IN THEIR IDEAS (ALTHOUGH GFS IS MUCH SLOWER IN DEPARTING THE
LOW)...WILL FOLLOW THAT IDEA FOR NOW FOR POPS (CHANCE/LIKELY) AND
WIND (GUSTY NORTHWEST WINDS TO 30KTS ON FRIDAY NIGHT) FORECAST.
LATE ARRIVING 00Z ECMWF HAS BACKED AWAY FROM THE LOW PRESSURE SYSTEM
AND JUST KEEPING A BROAD SURFACE TROUGH MOVING THROUGH. BASED OFF
THE 12Z ECMWF ENSEMBLE MEMBERS...THAT DOESN/T SEEM TO UNREASONABLE.
SATURDAY SHOULD SEE A DIMINISHING OF BOTH OF THOSE AS THE LOW PULLS
OUT OF THE AREA AND A HIGH PRESSURE RIDGE MOVES IN FROM THE
SOUTHWEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 741 AM EDT SUN SEP 28 2014
VFR CONDITIONS WILL CONTINUE TODAY AT KIWD/KCMX/KSAW AHEAD OF A
SHARP COLD FRONT DROPPING S THRU NRN ONTARIO. LAKE BREEZE
DEVELOPMENT THIS AFTN COULD TRIGGER ISOLD -SHRA IN CNTRL UPPER
MI...BUT POTENTIAL IS VERY LOW FOR KSAW TO BE AFFECTED BY A -SHRA IF
IN FACT SOME DO DEVELOP. SO...NO MENTION WAS INCLUDED IN FCST. AS
THE COLD FRONT DROPS ACROSS THE AREA TONIGHT...EXPECT ALL TERMINALS
TO FALL ABRUPTLY TO IFR/LIFR. -SHRA/-RA WILL SPREAD S BEHIND THE
COLD FRONT AS WELL WITH KCMX MOSTLY LIKELY TO SEE PCPN. BEST
POTENTIAL FOR PCPN AT KIWD/KSAW WILL OCCUR NEAR THE END OR JUST
BEYOND THIS FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 603 AM EDT SUN SEP 28 2014
SHARP COLD FRONT CURRENTLY OVER NRN ONTARIO WILL DROP S...PASSING
ACROSS LAKE SUPERIOR THIS AFTN AND TONIGHT. WITH A WEAK PRES
GRADIENT AHEAD OF FRONT...WINDS WILL REMAIN ON THE LIGHT SIDE
TODAY...MOSTLY UNDER 20KT. ON THE FLIP SIDE...DRAMATIC CHANGES WILL
OCCUR AFTER THE FRONT PASSES. STRONG COLD AIR ADVECTION COMBINED
WITH POST FRONTAL PRES RISES WILL RESULT IN N TO NE WINDS OF 20-30KT
ACROSS MUCH OF LAKE SUPERIOR WITH A FEW GALE FORCE GUSTS POSSIBLE
ACROSS CENTRAL PORTIONS OF THE LAKE TONIGHT INTO MON MORNING. WINDS
WILL THEN GRADUALLY DIMINISH MON AFTN AND NIGHT AS HIGH PRES BUILDS
OVER NRN ONTARIO. WINDS UNDER 20KT WILL BE THE RULE TUE THRU THU.
HOWEVER...AS PRES GRADIENT TIGHTENS SOME ON WED BTWN DEPARTING HIGH
PRES AND AN APPROACHING COLD FRONT...SOUTHERLY WINDS MAY BE A LITTLE
STRONGER ON WED...MAINLY OVER ERN LAKE SUPERIOR. LOOKING FARTHER
OUT...THERE ARE SOME HINTS THAT A STRENGTHENING FALL STORM SYSTEM
WILL LIFT THRU THE UPPER LAKES LATE WEEK...BRINGING THE POTENTIAL
FOR GALES.
&&
.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 RALEIGH NC
700 AM EDT SUN SEP 28 2014
.SYNOPSIS...HIGH PRESSURE WILL EXTEND ACROSS THE MIDDLE ATLANTIC
STATES THROUGH TONIGHT. A WEAK AREA OF LOW PRESSURE WILL DEVELOP AND
TRACK ACROSS THE GULF COAST MONDAY...THEN OFF THE SOUTHEAST COAST
MONDAY NIGHT AND TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM SUNDAY...
LOW-MID LEVEL RIDGE ALONG THE EAST COAST THIS MORNING...INCLUDING A
1023 MB SFC HIGH CENTERED OVER THE MIDDLE ATLANTIC STATES...WILL
DRIFT OFFSHORE TODAY. MEANWHILE...A MID-UPPER TROUGH OVER THE
CENTRAL CONUS...ONE COMPRISED OF A COUPLE OF WELL-DEFINED
CIRCULATIONS OVER IA AND EASTERN TX...WILL MOVE INITIALLY SLOWLY
EAST THIS MORNING THEN ACCELERATE EASTWARD LATER TODAY AND
TONIGHT...OWING TO THE APPROACH OF A KICKER TROUGH FROM SW CANADA.
THE NORTHERN EDGE OF AN AREA OF HIGH BASED STRATOCUMULUS (6-8
THOUSAND FT) ARCING FROM SE NC TO THE NC FOOTHILLS (JUST WEST OF THE
YADKIN) WILL PIVOT NORTHWESTWARD AND SPREAD - IN A THINNING/
SCATTERING STATE INTO THE SOUTHERN AND WESTERN PIEDMONT TODAY PER
THE 00Z GFS AND RECENT RAP RUNS...WHEREAS THE 00Z NAM APPEARED TOO
AGGRESSIVE/PESSIMISTIC WITH THESE SKY CONDITIONS PER COMPARISON TO
RECENT OBSERVATIONAL DATA. AS SUCH...THE NAM/S DEPICTION OF BKN TO
OVC 6-8 THOUSAND FT SKY COVERAGE OVER THE SOUTHERN AND WESTERN
PIEDMONT BY 18Z IS CONSIDERED AN OUTLIER AND WILL BE DISCOUNTED IN
FAVOR OF GENERALLY SCT COVERAGE AND ASSOCIATED PARTLY CLOUDY
CONDITIONS THROUGH THE BETTER PART OF THE AFTERNOON. THE REMAINDER
OF CENTRAL NC SHOULD REMAIN MOSTLY SUNNY...BENEATH PASSING CIRRUS
THAT WILL GRADUALLY THICKEN FROM THE WEST LATE. PROJECTED LOW LEVEL
THICKNESS VALUES ABOUT 10 METERS HIGHER THAN THOSE OF SATURDAY
SUPPORT HIGHS IN THE UPPER 70S TO LOWER 80S...OR ABOUT 3 DEGREES
HIGHER THAN SATURDAY.
TONIGHT: NWP GUIDANCE IS IN RELATIVELY GOOD AGREEMENT REGARDING THE
APPROACH OF THE MID-UPPER TROUGH FROM THE WEST...WITH A CONSENSUS
POSITION OF THE PARENT UPPER LOW OVER THE LOWER OH VALLEY/NORTHERN
TN VALLEY BY 12Z MON. ASSOCIATED HEIGHT FALLS ALOFT...ON THE ORDER
30-50 METERS AT H5 OVERNIGHT IN CENTRAL NC...SHOULD SUPPORT THE
NORTHEASTWARD EXPANSION/DEVELOPMENT OF MID AND HIGH LEVEL/MIXED
PHASE-GENERATED RAIN. WITH CLOUD BASES EXPECTED TO HOLD AOA 10
THOUSAND FT...IT IS LIKELY THAT ONLY VIRGA WILL FALL FROM THESE MID
LEVEL CEILINGS...OR PERHAPS A FEW SPRINKLES INVOF THE YADKIN RIVER
AROUND DAYBREAK. OTHERWISE...INITIALLY PARTLY TO MOSTLY CLEAR SKIES
THIS EVENING OVER THE NE PIEDMONT AND NORTHERN COASTAL PLAIN...AND
DELAYED ARRIVAL OF THE THICKER CLOUD COVER...SHOULD SUPPORT GOOD
RADIATIONAL COOLING CONDITIONS. LOWS THERE ARE LIKELY TO DIP INTO
THE MID-UPPER 50S...RANGING TO LOWER-MIDDLE 60S OVER THE SOUTHERN
PIEDMONT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 315 AM SUNDAY...
SHORTWAVE EXTENDING FROM THE OHIO VALLEY TO THE MISSISSIPPI VALLEY
MONDAY MORNING... WITH A WEAK SURFACE LOW DEVELOPING OVER GA/FL.
THIS IS FURTHER SOUTH THAN PREVIOUS MODEL RUNS. TAIL END OF THE
UPPER JET EXTENDING SOUTHWARD FROM NEW ENGLAND WILL PROVIDE UPPER
LEVEL SUPPORT FOR WIDESPREAD LIFT... HOWEVER GIVEN THE POSITION OF
THE LOW FURTHER SOUTH... MOISTURE TRANSPORT LOOKS LIMITED. HAVE
SCALED BACK QPF TO UNDER A HALF INCH ACROSS THE AREA... LOWER
AMOUNTS CLOSER TO THE VA BORDER.
SHORTWAVE WILL BE APPROACHING THE COAST TUESDAY MORNING... AS THE
SURFACE LOW MOVES NORTHEAST ALONG THE COAST. PRECIP WILL DIMINISH AS
SUBSIDENCE AND MIDLEVEL DRYING FOLLOWS... HOWEVER LINGERING LOW
LEVEL MOISTURE MAY BE SUFFICIENT TO PRODUCE SOME PATCHY LIGHT
RAIN/DRIZZLE IN TO WEDNESDAY. WEAK COLD AIR DAMMING WILL ALSO
PROLONG LOW LEVEL CLOUD COVER IN TO EARLY WEDNESDAY. PARENT HIGH
REMAINS FAR TO THE NORTH OVER QUEBEC... UNFAVORABLY POSITIONED FOR A
PROLONGED DAMMING EVENT... AND ANY REMAINING WEDGE WILL ERODE DURING
THE DAY. HIGH TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THIS
TIME.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 318 AM SUNDAY...
HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH THURSDAY... AS A
STRONG TROUGH APPROACHES FROM THE WEST. HIGH TEMPERATURES WILL TREND
TOWARD NORMAL THURSDAY AND FRIDAY AHEAD OF THIS SYSTEM. MODEL
AGREEMENT CONTINUES TO BE GOOD... WITH THE PARENT LOW MOVING NORTH
THROUGH THE GREAT LAKES AND THE ASSOCIATED COLD FRONT CROSSING THE
AREA FRIDAY NIGHT/EARLY SATURDAY. HIGH TEMPERATURES SATURDAY WILL
LIKELY BE DEPENDENT ON THE PASSAGE OF THIS FRONT.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 700 AM SUNDAY...
UNDER THE CONTINUED INFLUENCE OF MODIFIED CANADIAN HIGH PRESSURE
OVER THE MIDDLE ATLANTIC STATES...MAINLY VFR CONDITIONS WILL PREVAIL
THROUGH THE TAF PERIOD. THE EXCEPTION TO VFR WILL BE A BRIEF PERIOD
OF LINGERING SHALLOW FOG AND ASSOCIATED LIFR-MVFR VISIBILITY
RESTRICTIONS AT KRWI/KRDU/KFAY THIS MORNING. OTHERWISE...BENEATH
PERIODS OF PASSING CIRRUS...AN AREA OF 6-9 THOUSAND FT STRATOCUMULUS
NEAR THE SC BORDER THIS MORNING WILL SPREAD NORTH INTO CENTRAL NC
TODAY...MOST NOTABLY AT WESTERN TERMINALS WHERE ASSOCIATED CEILINGS
COULD RESULT BY LATE THIS AFTERNOON OR EVENING. THE APPROACH OF AN
UPPER LEVEL TROUGH FROM THE WEST WILL CAUSE MID-HIGH CLOUDS TO
THICKEN AND LOWER FROM WEST TO EAST LATE TONIGHT...WITH PERHAPS A
FEW SPRINKLES FROM MID LEVEL CLOUD BASES AT TRIAD TERMINALS AROUND
DAYBREAK MONDAY.
OUTLOOK: A PERIOD OF MEASURABLE RAIN AND CEILINGS LOWERING INTO MVFR
RANGE WILL THEN BE POSSIBLE MON INTO EARLY TUE...ESPECIALLY AT
KFAY...AS SURFACE LOW PRESSURE SYSTEM DEVELOPS AND TRACKS ACROSS THE
GULF COAST (WELL SOUTH OF CENTRAL NC). A SURGE IN NE LOW LEVEL FLOW
IN THE WAKE OF THE LOW PRESSURE SYSTEM MAY PRODUCE ANOTHER BRIEF
PERIOD OF MVFR CEILINGS AT KRWI AND KFAY ON WED.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...SEC
LONG TERM...SEC
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1200 PM MDT SUN SEP 28 2014
.UPDATE...
ISSUED AT 1200 PM MDT SUN SEP 28 2014
WILL ALLOW FLASH FLOOD WATCH TO EXPIRE FOR MUCH OF WESTERN
COLORADO AT NOON. HOWEVER...SHORT RANGE MODELS INDICATED THAT A
PORTION OF SOUTHWEST COLORADO WILL STILL HAVE THE POTENTIAL FOR
HEAVY RAIN. MODEL INDICATED DECREASE IN PW FOR THIS AFTERNOON
APPEARS SUSPECT AND GIVEN INSTABILITY...OROGRAPHIC LIFT...AND
DYNAMIC COMPONENT ASSOCIATED WITH JET NOSING INTO THE AREA OPTED TO
EXTEND THE FLASH FLOOD WATCH THROUGH 6 PM. AREAS AFFECTED INCLUDE
DURANGO AND PAGOSA SPRINGS AND SURROUNDING AREAS AND THE SOUTHWEST
SAN JUAN MOUNTAINS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 321 AM MDT SUN SEP 28 2014
LIGHT TO MODERATE RAINSHOWERS CONTINUE THIS MORNING...STRADDLING
BOTH SIDES OF THE UT/CO BORDER WITH A FEW RUMBLES OF THUNDER MIXED
IN. UPPER LEVEL SUPPORT WANED LAST NIGHT AND THIS MORNING AS A JET
STREAK CURVES BACK AROUND THE CLOSED LOW OVER NV. THIS STREAK IS
THE SUPPORT THAT`S CAUSING THE RAINSHOWERS. A STRONGER JET STREAK
IS PROGGED TO ROUND THE BASE OF SAID LOW PRESSURE AND MOVE ACROSS
THE CWA THIS AFTERNOON AND EVENING. FOR THE REMAINDER OF THE
MORNING HOURS...RAINSHOWERS WILL CONTINUE WITH A FEW BEING LOCALLY
HEAVY BUT WITH THE LOW SLOWLY MOVING E AND PRECIP FOLLOWING
SUIT...FLASH FLOOD CONCERNS WILL LOWER SO WILL DROP ERN UT FLASH
FLOOD WATCH WITH THIS MORNINGS PACKAGE. THE WATCH FOR WRN COLORADO
STILL STAY IN PLACE HOWEVER WITH SHOWERS AND EMBEDDED STORMS
CONTINUING TO TRACK EWRD. THE HRRR IS AGAIN PERFORMING WELL AND
IS INDICATING BY 0700L THAT PRECIP SHOULD BE ENDING FOR ERN UT
WHILE MUCH OF WRN COLORADO...EXCEPT THE NRN MTNS...WILL BE SEEING
SOME RAINFALL.
NEXT CONCERN WILL BE STORMS THIS AFTERNOON. CURRENT IR SATELLITE
SHOWS PLENTY OF DRY AIR OVER WRN/SRN UT THAT WILL MOVE INTO OUR
CWA TODAY. AS THIS OCCURS...BULK SHEAR WILL REMAIN ESPECIALLY
HIGH AND THIS MIXED WITH AFTERNOON HEATING AND UPPER LEVEL
DYNAMIC SUPPORT WILL LEND ITSELF FOR SOME STRONG THUNDERSTORMS
THIS AFTERNOON. SOME STORMS MAY REACH SEVERE LIMITS WITH WIND
GUSTS OF 50 TO 60 MPH POSSIBLE ALONG WITH HALF- INCH SIZED HAIL OR
LARGER UNDER AND NEAR THE STRONGEST CELLS. HRRR ALSO SHOWING THIS
CONVECTION FORMING FROM ABOUT 3PM ONWARDS. AS YOU CAN IMAGINE...AN
ACTIVE AFTERNOON IS EXPECTED.
SUNDAY NIGHT A SIGNIFICANT SPOKE OF ENERGY DIGS INTO THE BASE OF
THE LOW ELONGATING IT SOUTH TO NORTH. THE JET STREAK LIFTS NORTH
OF THIS AREA AND THE DRY SLOT LOWERS PRECIP WATER VALUES TO 0.25
SOUTH...0.5 INCH NORTH. THIS BRINGS A DIMINISHING OF SHOWERS
THROUGH THE EVENING AND OVERNIGHT. THE SOUTHERN SPOKE ROTATES NE
WITH THE ASSOCIATED 80KT JET LIFTING THROUGH THE FOUR CORNERS IN
THE MORNING. ASSOCIATED SURFACE COLD FRONT UNDER THE JET SUPPORT
WILL PRODUCE SOME MORNING SHOWERS IN THE SW SAN JUAN MOUNTAINS IN
SPITE OF THE DRIER AIR. THE LOW OPENS AS IT LIFTS NE MONDAY
AFTERNOON PROVIDING SUPPORT FOR MAINLY OROGRAPHIC SHOWERS AND
STORMS THROUGH THE AFTERNOON. AFTERNOON TEMPERATURES WILL BE 5-10
DEGREES BELOW AVERAGE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 321 AM MDT SUN SEP 28 2014
SOME SHOWERS MAY CONTINUE OVER THE NORTH MONDAY NIGHT THROUGH
TUESDAY NIGHT IN ACTIVE NW FLOW WITH ONLY MARGINAL MOISTURE AND
INSTABILITY AVAILABLE. 700MB TEMPERATURES HOVER NEAR 0C MONDAY FOR
A SNOW POSSIBLE DOWN TO NEAR 9000 FT IN THE PARK RANGE. ANY SNOW
ACCUMULATION BELOW TIMBERLINE WILL MELT ON TUESDAY AS TEMPERATURES
RECOVER TO NEAR NORMAL.
THE JET STREAM WILL DROP DOWN FROM THE PACNW WEDNESDAY AND CARVE
OUT A RELATIVELY WEAK TROUGH THAT WILL MOVE OVER THE AREA WED
EVENING AND THURSDAY MORNING. SOME ISOLD SHOWERS/STORMS ARE
EXPECTED WITH SOME SNOWFALL FOR THE HIGHER ELEVATIONS UP NORTH.
MAYBE AN INCH OR TWO POSSIBLE. BY THURSDAY MORNING...HIGH PRESSURE
SETS UP OVER THE WRN GREAT BASIN KEEPING US IN NW FLOW FOR THE
REMAINDER OF THE LONG TERM PERIOD WITH DRY CONDITIONS EXPECTED.
TEMPERATURES WILL BE BELOW NORMAL FOR MUCH OF THE LONG TERM PERIOD
SLOWLY WARMING UP TOWARDS THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1049 AM MDT SUN SEP 28 2014
WIDESPREAD RAIN SHOWERS WILL PERSIST OVER THE AREA INTO THIS
EVENING...THEN BECOME MORE LOCALIZED OVERNIGHT. THUNDERSTORMS
EMBEDDED IN THE SHOWERS WILL ALSO INCREASE FROM THE SOUTH AND
WEST EARLY THIS AFTERNOON...WITH PEAK THUNDERSTORM ACTIVITY
EXPECTED DURING THE LATE AFTERNOON TO EARLY EVENING PERIOD. AT
AREA AIRPORTS VFR WILL BE THE PREDOMINANT FLIGHT CATEGORY...
HOWEVER BRIEF PERIODS OF MVFR OR EVEN IFR WILL BE POSSIBLE IN THE
HEAVIER SHOWERS. WIDESPREAD MOUNTAIN OBSCURATIONS ARE EXPECTED.
THE STRONGEST THUNDERSTORMS MAY PRODUCE STRONG GUSTY OUTFLOW
WINDS IN EXCESS OF 45 KTS AND/OR SMALL HAIL UP TO ONE HALF INCH.
SHOWERS AND ESPECIALLY THUNDERSTORMS WILL DIMINISH OVERNIGHT.
WHILE ACTIVITY WILL BE LESS ON MONDAY THE CHANCE OF SHOWERS AND
THUNDERSTORMS WILL CONTINUE. MORNING FOG WILL BE POSSIBLE IN MOST
VALLEY AREAS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH UNTIL 6 PM MDT THIS EVENING FOR COZ019-022.
FLASH FLOOD WATCH UNTIL 6 PM MDT THIS EVENING FOR COZ023.
UT...NONE.
&&
$$
UPDATE...NL
SHORT TERM...TGR/JOE
LONG TERM...JOE/TGR
AVIATION...EH
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1049 AM MDT SUN SEP 28 2014
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 321 AM MDT SUN SEP 28 2014
LIGHT TO MODERATE RAINSHOWERS CONTINUE THIS MORNING...STRADDLING
BOTH SIDES OF THE UT/CO BORDER WITH A FEW RUMBLES OF THUNDER MIXED
IN. UPPER LEVEL SUPPORT WANED LAST NIGHT AND THIS MORNING AS A JET
STREAK CURVES BACK AROUND THE CLOSED LOW OVER NV. THIS STREAK IS
THE SUPPORT THAT`S CAUSING THE RAINSHOWERS. A STRONGER JET STREAK
IS PROGGED TO ROUND THE BASE OF SAID LOW PRESSURE AND MOVE ACROSS
THE CWA THIS AFTERNOON AND EVENING. FOR THE REMAINDER OF THE
MORNING HOURS...RAINSHOWERS WILL CONTINUE WITH A FEW BEING LOCALLY
HEAVY BUT WITH THE LOW SLOWLY MOVING E AND PRECIP FOLLOWING
SUIT...FLASH FLOOD CONCERNS WILL LOWER SO WILL DROP ERN UT FLASH
FLOOD WATCH WITH THIS MORNINGS PACKAGE. THE WATCH FOR WRN COLORADO
STILL STAY IN PLACE HOWEVER WITH SHOWERS AND EMBEDDED STORMS
CONTINUING TO TRACK EWRD. THE HRRR IS AGAIN PERFORMING WELL AND
IS INDICATING BY 0700L THAT PRECIP SHOULD BE ENDING FOR ERN UT
WHILE MUCH OF WRN COLORADO...EXCEPT THE NRN MTNS...WILL BE SEEING
SOME RAINFALL.
NEXT CONCERN WILL BE STORMS THIS AFTERNOON. CURRENT IR SATELLITE
SHOWS PLENTY OF DRY AIR OVER WRN/SRN UT THAT WILL MOVE INTO OUR
CWA TODAY. AS THIS OCCURS...BULK SHEAR WILL REMAIN ESPECIALLY
HIGH AND THIS MIXED WITH AFTERNOON HEATING AND UPPER LEVEL
DYNAMIC SUPPORT WILL LEND ITSELF FOR SOME STRONG THUNDERSTORMS
THIS AFTERNOON. SOME STORMS MAY REACH SEVERE LIMITS WITH WIND
GUSTS OF 50 TO 60 MPH POSSIBLE ALONG WITH HALF- INCH SIZED HAIL OR
LARGER UNDER AND NEAR THE STRONGEST CELLS. HRRR ALSO SHOWING THIS
CONVECTION FORMING FROM ABOUT 3PM ONWARDS. AS YOU CAN IMAGINE...AN
ACTIVE AFTERNOON IS EXPECTED.
SUNDAY NIGHT A SIGNIFICANT SPOKE OF ENERGY DIGS INTO THE BASE OF
THE LOW ELONGATING IT SOUTH TO NORTH. THE JET STREAK LIFTS NORTH
OF THIS AREA AND THE DRY SLOT LOWERS PRECIP WATER VALUES TO 0.25
SOUTH...0.5 INCH NORTH. THIS BRINGS A DIMINISHING OF SHOWERS
THROUGH THE EVENING AND OVERNIGHT. THE SOUTHERN SPOKE ROTATES NE
WITH THE ASSOCIATED 80KT JET LIFTING THROUGH THE FOUR CORNERS IN
THE MORNING. ASSOCIATED SURFACE COLD FRONT UNDER THE JET SUPPORT
WILL PRODUCE SOME MORNING SHOWERS IN THE SW SAN JUAN MOUNTAINS IN
SPITE OF THE DRIER AIR. THE LOW OPENS AS IT LIFTS NE MONDAY
AFTERNOON PROVIDING SUPPORT FOR MAINLY OROGRAPHIC SHOWERS AND
STORMS THROUGH THE AFTERNOON. AFTERNOON TEMPERATURES WILL BE 5-10
DEGREES BELOW AVERAGE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 321 AM MDT SUN SEP 28 2014
SOME SHOWERS MAY CONTINUE OVER THE NORTH MONDAY NIGHT THROUGH
TUESDAY NIGHT IN ACTIVE NW FLOW WITH ONLY MARGINAL MOISTURE AND
INSTABILITY AVAILABLE. 700MB TEMPERATURES HOVER NEAR 0C MONDAY FOR
A SNOW POSSIBLE DOWN TO NEAR 9000 FT IN THE PARK RANGE. ANY SNOW
ACCUMULATION BELOW TIMBERLINE WILL MELT ON TUESDAY AS TEMPERATURES
RECOVER TO NEAR NORMAL.
THE JET STREAM WILL DROP DOWN FROM THE PACNW WEDNESDAY AND CARVE
OUT A RELATIVELY WEAK TROUGH THAT WILL MOVE OVER THE AREA WED
EVENING AND THURSDAY MORNING. SOME ISOLD SHOWERS/STORMS ARE
EXPECTED WITH SOME SNOWFALL FOR THE HIGHER ELEVATIONS UP NORTH.
MAYBE AN INCH OR TWO POSSIBLE. BY THURSDAY MORNING...HIGH PRESSURE
SETS UP OVER THE WRN GREAT BASIN KEEPING US IN NW FLOW FOR THE
REMAINDER OF THE LONG TERM PERIOD WITH DRY CONDITIONS EXPECTED.
TEMPERATURES WILL BE BELOW NORMAL FOR MUCH OF THE LONG TERM PERIOD
SLOWLY WARMING UP TOWARDS THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1049 AM MDT SUN SEP 28 2014
WIDESPREAD RAIN SHOWERS WILL PERSIST OVER THE AREA INTO THIS
EVENING...THEN BECOME MORE LOCALIZED OVERNIGHT. THUNDERSTORMS
EMBEDDED IN THE SHOWERS WILL ALSO INCREASE FROM THE SOUTH AND
WEST EARLY THIS AFTERNOON...WITH PEAK THUNDERSTORM ACTIVITY
EXPECTED DURING THE LATE AFTERNOON TO EARLY EVENING PERIOD. AT
AREA AIRPORTS VFR WILL BE THE PREDOMINANT FLIGHT CATEGORY...
HOWEVER BRIEF PERIODS OF MVFR OR EVEN IFR WILL BE POSSIBLE IN THE
HEAVIER SHOWERS. WIDESPREAD MOUNTAIN OBSCURATIONS ARE EXPECTED.
THE STRONGEST THUNDERSTORMS MAY PRODUCE STRONG GUSTY OUTFLOW
WINDS IN EXCESS OF 45 KTS AND/OR SMALL HAIL UP TO ONE HALF INCH.
SHOWERS AND ESPECIALLY THUNDERSTORMS WILL DIMINISH OVERNIGHT.
WHILE ACTIVITY WILL BE LESS ON MONDAY THE CHANCE OF SHOWERS AND
THUNDERSTORMS WILL CONTINUE. MORNING FOG WILL BE POSSIBLE IN MOST
VALLEY AREAS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH UNTIL NOON MDT TODAY FOR COZ001>003-006-007-
009-011-013-017>022.
UT...NONE.
&&
$$
SHORT TERM...TGR/JOE
LONG TERM...JOE/TGR
AVIATION...EH
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
606 PM EDT SUN SEP 28 2014
.SYNOPSIS...
LOW PRESSURE ALONG THE GULF COAST WILL PUSH INCREASING MOISTURE
INTO THE AREA TONIGHT ALONG WITH INCREASING CHANCES OF RAIN
SHOWERS. RAIN IS EXPECTED MONDAY AND MONDAY NIGHT WITH LINGERING
LOW LEVEL MOISTURE AND AN UPPER TROUGH LEADING TO CONTINUED RAIN
CHANCES TUESDAY. DRIER AIR WILL ENTER THE REGION LATE
TUESDAY...AND PROVIDE FAIR WEATHER WEDNESDAY AND THURSDAY. THE
NEXT WEATHER SYSTEM WILL BRING A CHANCE OF RAIN FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
WEAK SURFACE HIGH PRESSURE CONTINUES TO RIDGE INTO THE FORECAST
AREA FROM THE NORTH THIS EVENING WITH A STALLED BOUNDARY ALONG THE
SOUTHEAST COAST. LOW PRESSURE DEVELOPING ALONG THE GULF COAST HAS
RESULTED IN INCREASING MOISTURE AND CLOUDS ACROSS THE AREA.
MESOANALYSIS SHOWS A GRADIENT IN PRECIPITABLE WATER VALUES FROM
NORTH TO SOUTH WITH VALUES NEAR 1.5 INCHES NORTH TO 1.9 INCHES
SOUTH. PWAT VALUES WILL GRADUALLY INCREASE OVERNIGHT AS
CYCLOGENESIS TAKES PLACE ALONG THE GULF. REGIONAL RADAR SHOWS
SHOWERS OFFSHORE AND A FEW WEAK RETURNS ACROSS THE EASTERN
MIDLANDS AND CSRA. EXPECT SHOWERS TO BEGIN MOVING INTO THE CSRA
AND SOUTHERN MIDLANDS TONIGHT WITH CHANCES RAMPING UP TOWARD
DAYBREAK. CLOUD COVER AND SHOWER ACTIVITY SHOULD RESTRICT LOW
TEMPERATURES TO THE MIDDLE TO UPPER 60S. MODEL GUIDANCE WAS VERY
CLOSE WITH OVERNIGHT LOWS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AN AREA OF LOW PRESSURE IS FORECAST TO DEVELOP ALONG THE
NORTHEASTERN GULF OF MEXICO COAST OVERNIGHT. THIS LOW IS EXPECTED
TO SLOWLY MOVE ALONG AN OLD FRONTAL BOUNDARY THAT HAS BEEN OFF TO
THE SOUTH AND EAST OF THE CWA THE PAST SEVERAL DAYS. AS THE LOW
STRENGTHENS...LOW-LEVEL WINDS ACROSS THE FORECAST AREA SHOULD BECOME
MORE EASTERLY AND OFF THE ATLANTIC THROUGH THE DAY MONDAY. THE LOW
IN THE GULF WILL ALSO BE SPREADING GULF MOISTURE NORTHWARD.
MEANWHILE ALOFT...THE UPPER RIDGE THAT HAS BEEN ACROSS THE AREA WILL
PUSH EASTWARD...ALLOWING AN UPPER TROUGH AND ASSOCIATED ENERGY TO
SWING TOWARDS THE AREA FROM THE WEST. THIS UPPER SYSTEM WILL PUSH
THROUGH ON MONDAY...WHILE THE SURFACE LOW TRACKS OFF TO THE SOUTH OF
THE AREA. THERE WILL BE PLENTY OF MOISTURE FOR THE UPPER SYSTEM TO
TAP AS IT MOVES THROUGH THE REGION...AND EXPECT TO SEE PLENTY OF
RAINFALL DURING THE DAY MONDAY. THIS RAIN WILL LINGER INTO MONDAY
NIGHT...AND THEN SHOULD BE PUSHING EAST OF THE CWA BY TUESDAY
MORNING. WILL HOLD ONTO CATEGORICAL POPS MONDAY...THEN LIKELY POPS
MONDAY NIGHT...WITH LINGERING SLIGHT CHANCE POPS EARLY TUESDAY
MORNING...THEN DRY TUESDAY AFTERNOON AND NIGHT. WITH THE MAIN
SURFACE LOW WELL SOUTH OF THE AREA...EXPECT MAINLY SHOWERS AS THE
UPPER LOW MOVES THROUGH...WITH MAYBE AN ISOLATED THUNDERSTORM MONDAY
AFTERNOON. AS FOR TEMPERATURES...DO NOT EXPECT MUCH DIURNAL WARMING
THROUGH THE DAY MONDAY WITH ALL THE CLOUDS AND RAINFALL
EXPECTED...SO ONLY WENT A FEW DEGREES WARMER THAN THE MORNING LOWS
ON MONDAY. MONDAY NIGHT SHOULD BE BACK IN THE 60S AGAIN. WITH SOME
BREAKS IN THE CLOUDS POSSIBLE ON TUESDAY...READINGS WILL CLIMB INTO
THE LOWER TO MIDDLE 70S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE UPPER TROUGH WILL BE EAST OF THE REGION BY WEDNESDAY...WITH
ANOTHER WEAK RIDGE BUILDING OVER THE AREA BOTH ALOFT ANT AT THE
SURFACE THROUGH THURSDAY NIGHT. THIS SHOULD KEEP THE FORECAST DRY
AT THIS TIME. A STRONGER UPPER TROUGH LOOKS TO MOVE INTO THE REGION
BY FRIDAY...WITH THE RAIN CHANCES INCREASING AHEAD OF AN APPROACHING
COLD FRONT. THIS FRONT SHOULD BE MOVING EAST OF THE AREA BY
SATURDAY. BEHIND THE FRONT...DRY CONDITIONS RETURN. TEMPERATURES
THROUGH THE PERIOD REMAIN SLIGHTLY BELOW NORMAL.
&&
.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
MOISTURE WILL BE ON THE INCREASE DURING THE TAF PERIOD. LOW PRESSURE
DEVELOPING IN THE GULF OF MEXICO WILL TRACK NORTHWARD ALONG THE
FRONTAL ZONE NEAR THE SOUTHEAST COAST. WE MAINLY USED AN AVERAGE OF
THE HRRR AND GFS LAMP FOR THE TIMING OF DETERIORATING CONDITIONS.
RAIN WILL LIKELY BECOME WIDESPREAD FROM SOUTHWEST TO NORTHEAST
DURING THE DAY MONDAY. THE NAM AND GFS MOS ARE IN GOOD AGREEMENT
WITH WINDS NORTHEAST 10 KNOTS OR LESS. THE THUNDERSTORM CHANCE
SHOULD REMAIN LOW WITH THE WARM SECTOR WELL SOUTH AND EAST OF THE
FORECAST AREA. ALSO...THE MODELS INDICATE JUST WEAK ELEVATED
INSTABILITY.
EXTENDED AVIATION OUTLOOK...WIDESPREAD MVFR OF IFR CONDITIONS MAY
CONTINUE THROUGH TUESDAY ASSOCIATED WITH LOW PRESSURE NEAR THE
COAST. SHOWERS AND THUNDERSTORMS MAY BE ASSOCIATED WITH A COLD FRONT
FRIDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
150 PM EDT SUN SEP 28 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 603 AM EDT SUN SEP 28 2014
...ONE MORE UNSEASONABLY WARM DAY TODAY...AND QUITE LIKELY THE LAST
DAY WITH TEMPERATURES THIS HIGH FOR THE REST OF THE YEAR...
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...STRONG RIDGE THAT WAS
EXTENDING INTO NRN ONTARIO IS BEING SUPPRESSED BY SHORTWAVE TROF
THAT HAS BEEN MOVING ACROSS SOUTHERN CANADA. THIS TROF IS SUPPORTING
A SHARP COLD FRONT THAT CURRENTLY EXTENDS FROM SE ND TO JUST S OF
JAMES BAY. JUST BEHIND FRONT...TEMPS QUICKLY FALL OFF INTO THE 40S
AND 30S...GIVING AN IDEA OF THE DRAMATICALLY COLDER CONDITIONS THAT
WILL SWEEP INTO THE AREA FOR MON. MID LEVEL LOW THAT WAS CENTERED
ALONG THE IA/MO BORDER 24 HRS AGO HAS MOVED LITTLE...NOW OVER IA.
SCT/BKN MAINLY THIN HIGH CLOUDS TO THE NE OF THIS FEATURE HAVE
HELPED TO KEEP RADIATION FOG A LITTLE LESS WIDESPREAD AND LESS DENSE
EARLY THIS MORNING.
FCST SOUNDINGS SHOW LITTLE CHANGE IN TEMP PROFILE FROM YESTERDAY...
SO LARGELY UTILIZED YESTERDAYS MAX TEMPS AS A BASIS FOR TODAYS MAX
TEMPS. TEMP RISE THIS MORNING SHOULD ALSO FOLLOW A SIMILAR DIURNAL
CURVE TO WHAT OCCURRED YESTERDAY MORNING. PRETTY GOOD CHC RECORD
HIGH OF 77F FOR NWS KMQT SITE WILL FALL TODAY. SHARP COLD FRONT TO
THE N WILL DRIFT S TODAY AND SHOULD REACH THE KEWEENAW LATE IN THE
AFTN. AS IS CURRENTLY NOTED WITH FRONTAL BOUNDARY...PCPN WILL
CONTINUE TO OCCUR MOSTLY ON THE COLD SIDE OF THE SFC COLD FRONT AS
NICE FRONTOGENETICAL CIRCULATION UNDER RIGHT ENTRANCE OF UPPER JET
WILL CONTINUE TO SUPPORT PCPN ON THE COLD SIDE OF THE SFC FRONT.
THAT SAID...WEAK PRES GRADIENT AHEAD OF FRONT WILL ALLOW LAKE
BREEZES TO DEVELOP TODAY. WITH A FEW HUNDRED J/KG OF MLCAPE...LAKE
BREEZE MAY BE SUFFICIENT TO KICK OFF ISOLD SHRA THIS AFTN ACROSS
PORTIONS OF THE CNTRL AND ERN FCST AREA. MOST HIGH RES MODEL
GUIDANCE CONTINUES TO SHOW THIS POTENTIAL.
SFC COLD FRONT WILL CONTINUE TO DRIFT S TONIGHT WITH PCPN REMAINING
MOSTLY ON THE COLD SIDE OF THE BOUNDARY...SUPPORTED BY
FRONTOGENETICAL CIRCULATION AS DISCUSSED ABOVE. TRAILING SHORTWAVE
CURRENTLY OVER SCNTRL CANADA WILL DIG INTO THE UPPER GREAT LAKES
MON. WITH BEST OVERLAP OF FGEN AND DEEP LAYER FORCING FROM SHORTWAVE
PER QVECTORS PASSING JUST N AND E OF FCST AREA...HEAVIER/STEADIER
SHRA/RA SHOULD PASS N AND E OF THE AREA. HOWEVER...DECENT FORCING
STILL SUPPORTS LIKELY TO CATEGORICAL POPS SPREADING SE TO THE
KEWEENAW AFTER MIDNIGHT TONIGHT AND TO WRN AND NRN UPPER MI BY 12Z
MON.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 326 AM EDT SUN SEP 28 2014
MONDAY WILL BE A SIGNIFICANT CHANGE IN THE WEATHER FOR UPPER
MICHIGAN...AS A COLD FRONT SWEEPS SOUTHEAST ACROSS THE AREA LATE
SUNDAY NIGHT THROUGH MONDAY. AS THIS OCCURS...EXPECT A BAND OF
SHOWERS TO BE MOVING ACROSS THE AREA ALONG AND BEHIND THE SURFACE
COLD FRONT BEFORE SINKING SOUTHEAST OF THE AREA ON MONDAY EVENING.
EVEN AS A BULK OF THE RAIN HAS SHIFTED OVER THE SOUTHEAST HALF OF
THE CWA ON MONDAY AFTERNOON...STILL EXPECT PLENTY OF LOW CLOUDS AND
LIGHT RAIN/DRIZZLE OVER THE AREA...ESPECIALLY THOSE FAVORED BY
NORTH-NORTHEAST UPSLOPE WINDS. IN ADDITION...WITH 900MB TEMPS
AROUND -1C AND LAKE SUPERIOR TEMPS BETWEEN 6-12C WOULD EXPECT AT
LEAST SOME LAKE ENHANCEMENT FOR THE AREAS NEAR LAKE SUPERIOR. WITH
INVERSION HEIGHTS RUNNING AROUND 3-3.5KFT DON/T EXPECT THE RAIN TO
BE TOO HEAVY...BUT ENOUGH TO LEAD TO A PERSISTANT LIGHT RAIN. WILL
CONTINUE TO SHOW LIKELY TO DEFINITE POPS IN THE FAVORED WIND
DIRECTIONS NEAR LAKE SUPERIOR AND AT LEAST CHANCES ELSEWHERE INTO
THE EVENING HOURS ON MONDAY. MODELS THEN SHOWING INVERSION HEIGHTS
FALLING THROUGH THE NIGHT UNDER THE INCREASED SUBSIDENCE FROM THE
HIGH PRESSURE RIDGE (HIGH CENTERED IN NORTHEAST ONTARIO) MOVING INTO
THE AREA. THUS...WILL SHOW DECREASING POPS THROUGH THE NIGHT AND
EVENTUALLY CLOUD COVER THROUGH THE DAY ON TUESDAY INTO TUESDAY
NIGHT. THE COMBINATION OF THE RAIN WITH STIFF NORTH-NORTHEAST WINDS
(15-25KTS) AND AFTERNOON TEMPERATURES IN THE MID 40S (30-35
DEGREES COLDER THAN THIS AFTERNOON) OVER THE NORTH HALF WILL MAKE
FOR A SIGNIFICANTLY DIFFERENT DAY THAN WHAT HAS BEEN EXPERIENCED
OVER THE LAST SEVERAL DAYS.
AS THE U.P. FINALLY STARTS TO BREAK OUT OF THE CLOUDS FROM MONDAY/S
SYSTEM...THE NEXT UPPER TROUGH WILL BE WORKING TOWARDS THE AREA ON
TUESDAY NIGHT AND BRING THE NEXT PERIOD OF UNSETTLED WEATHER TO THE
AREA FOR WEDNESDAY AFTERNOON THROUGH SATURDAY. THIS PERIOD OF
UNSETTLED WEATHER WILL BE ASSOCIATED WITH THE UPPER TROUGH
CURRENTLY OVER THE WESTERN CONUS SHIFTING EAST THROUGH THE AREA
DURING THAT PERIOD. THE FIRST WAVE FROM THAT UPPER TROUGH WILL MOVE
INTO THE AREA ON WEDNESDAY AFTERNOON AHEAD OF A WARM FRONT LIFTING
NORTHEAST TOWARDS THE AREA FROM A LOW NEAR LAKE WINNIPEG. WILL SHOW
INCREASING POPS FROM SOUTHWEST TO NORTHEAST FOR WEDNESDAY AFTERNOON
INTO WEDNESDAY NIGHT...WITH THE HIGHEST POPS (LIKELY) RUNNING ALONG
THE COLD FRONT THAT WILL BE MOVING THROUGH WESTERN AND CENTRAL
UPPER MICHIGAN LATE WEDNESDAY NIGHT AND THURSDAY. AS THIS COLD
FRONT IS SLOWLY WORKING EAST ACROSS THE AREA...A STRONG SHORTWAVE
DIVING SOUTHEAST THROUGH THE UPPER TROUGH WILL POTENTIALLY LEAD TO
THE INTENSIFICATION OF A LOW IN THE MID MISSISSIPPI VALLEY ON
THURSDAY EVENING. THIS LOW WILL CONTINUE TO INTENSIFY AS IT LIFTS
NORTHEAST ACROSS UPPER MICHIGAN ON FRIDAY MORNING AND THEN
NORTH-NORTHEAST INTO CANADA. WILL CONTINUE LIKELY POPS AS THIS LOW
MOVES THROUGH...ALTHOUGH CONFIDENCE IN THE STRENGTH IS LIMITED DUE
TO THE VARYING SOLUTIONS SHOWN IN THE MODELS (NOT UNEXPECTED WITH
UPSTREAM PHASING OF STRONG SHORTWAVES). THE 12Z ECMWF ENSEMBLE
MEMBERS ARE NOT MUCH OF A HELP WITH AROUND HALF OF THEM NOT SHOWING
A LOW RIDING UP THE COLD FRONT. WITH 12Z ECMWF AND 00Z GFS AT LEAST
SIMILAR IN THEIR IDEAS (ALTHOUGH GFS IS MUCH SLOWER IN DEPARTING THE
LOW)...WILL FOLLOW THAT IDEA FOR NOW FOR POPS (CHANCE/LIKELY) AND
WIND (GUSTY NORTHWEST WINDS TO 30KTS ON FRIDAY NIGHT) FORECAST.
LATE ARRIVING 00Z ECMWF HAS BACKED AWAY FROM THE LOW PRESSURE SYSTEM
AND JUST KEEPING A BROAD SURFACE TROUGH MOVING THROUGH. BASED OFF
THE 12Z ECMWF ENSEMBLE MEMBERS...THAT DOESN/T SEEM TO UNREASONABLE.
SATURDAY SHOULD SEE A DIMINISHING OF BOTH OF THOSE AS THE LOW PULLS
OUT OF THE AREA AND A HIGH PRESSURE RIDGE MOVES IN FROM THE
SOUTHWEST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 147 PM EDT SUN SEP 28 2014
VFR CONDITIONS WILL CONTINUE TODAY AT KIWD/KCMX/KSAW AHEAD OF A
SHARP COLD FRONT DROPPING S THRU NRN ONTARIO. LAKE BREEZE
DEVELOPMENT THIS AFTN COULD TRIGGER ISOLD -SHRA IN CNTRL UPPER
MI...BUT POTENTIAL IS VERY LOW FOR KSAW TO BE AFFECTED BY A -SHRA IF
IN FACT SOME DO DEVELOP. SO...NO MENTION WAS INCLUDED IN FCST. AS
THE COLD FRONT DROPS ACROSS THE AREA TONIGHT...EXPECT ALL TERMINALS
TO FALL ABRUPTLY TO IFR/LIFR. SOME IMPROVEMENT IS EXPECTED AT KCMX
LATE IN THE TAF PERIOD AS WINDS DIRECTIONS ARE LESS FAVORABLE FOR
UPSLOPE FLOW...BUT KIWD AND KSAW ARE NOT EXPECTED TO SEE MUCH
IMPROVEMENT LATE IN THE PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 603 AM EDT SUN SEP 28 2014
SHARP COLD FRONT CURRENTLY OVER NRN ONTARIO WILL DROP S...PASSING
ACROSS LAKE SUPERIOR THIS AFTN AND TONIGHT. WITH A WEAK PRES
GRADIENT AHEAD OF FRONT...WINDS WILL REMAIN ON THE LIGHT SIDE
TODAY...MOSTLY UNDER 20KT. ON THE FLIP SIDE...DRAMATIC CHANGES WILL
OCCUR AFTER THE FRONT PASSES. STRONG COLD AIR ADVECTION COMBINED
WITH POST FRONTAL PRES RISES WILL RESULT IN N TO NE WINDS OF 20-30KT
ACROSS MUCH OF LAKE SUPERIOR WITH A FEW GALE FORCE GUSTS POSSIBLE
ACROSS CENTRAL PORTIONS OF THE LAKE TONIGHT INTO MON MORNING. WINDS
WILL THEN GRADUALLY DIMINISH MON AFTN AND NIGHT AS HIGH PRES BUILDS
OVER NRN ONTARIO. WINDS UNDER 20KT WILL BE THE RULE TUE THRU THU.
HOWEVER...AS PRES GRADIENT TIGHTENS SOME ON WED BTWN DEPARTING HIGH
PRES AND AN APPROACHING COLD FRONT...SOUTHERLY WINDS MAY BE A LITTLE
STRONGER ON WED...MAINLY OVER ERN LAKE SUPERIOR. LOOKING FARTHER
OUT...THERE ARE SOME HINTS THAT A STRENGTHENING FALL STORM SYSTEM
WILL LIFT THRU THE UPPER LAKES LATE WEEK...BRINGING THE POTENTIAL
FOR GALES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...TITUS
MARINE...ROLFSON