Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/08/14
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
838 PM MST SUN SEP 7 2014
.SYNOPSIS...
MOISTURE WILL REMAIN IN PLACE ACROSS THE REGION FOR THE NEXT SEVERAL
DAYS AS FORMER HURRICANE NORBERT APPROACHES THE SOUTHERN CALIFORNIA
COAST. SHOWERS AND THUNDERSTORMS ARE EXPECTED AT TIMES THROUGH
TUESDAY...WITH SOME LOCATIONS POSSIBLY SEEING BRIEF PERIODS OF HEAVY
RAIN. A GRADUAL DRYING TREND IS EXPECTED TO BEGIN BY THE MIDDLE OF
THE WEEK AS HIGH PRESSURE SLOWLY REBUILDS OVER THE REGION.
&&
.DISCUSSION...
ISOLATED SHOWERS CONTINUE ACROSS PORTIONS OF NORTHWEST
ARIZONA...SOUTHERN NEVADA...AND EASTERN CALIFORNIA THIS
EVENING...WITH LITTLE TO NO CONVECTION NOTED ACROSS THE PHOENIX AREA
AND POINTS SOUTH. ASIDE FROM A FEW POP UP SHOWERS HERE AND
THERE...THE EVENING HAS BEEN RELATIVELY QUIET THUS FAR.
UPPER DIVERGENCE CONTINUES TO POSITIVELY INFLUENCE CONVECTION TO OUR
NORTHWEST...HOWEVER MID LEVEL SUBSIDENCE/ANTICYCLONIC FLOW ACROSS
CENTRAL/SOUTHERN ARIZONA HAS PUT A SUBSTANTIAL DENT IN ANY STORM`S
ABILITY TO GROW FOR MORE THAN A FEW VOLUME SCANS. 00Z NAM AND RECENT
RUNS OF THE HRRR CONTINUE TO ADVERTISE CONVECTION MOVING INTO THE
METRO OVERNIGHT...YET GIVEN SATELLITE TRENDS SHOWING WIDESPREAD
WARMING OF CLOUD TOPS ACROSS THE ENTIRE REGION...I`M SKEPTICAL THAT
THESE SOLUTIONS ARE GOING TO WORK OUT. THE 02Z RAP IS BEGINNING TO
GET A HANDLE ON THE CURRENT SITUATION AND IS PAINTING A MUCH DRIER
SOLUTION ACROSS THE AREA THROUGH MONDAY MORNING. MOST LIKELY
SCENARIO AT THIS POINT IS THAT SCATTERED SHOWERS WILL CONTINUE TO
DEVELOP...BUT STRUGGLE AND DISSIPATE QUICKLY THROUGH 12Z MONDAY. AS
SUCH...I AM GOING TO TRIM BACK POPS ACROSS THE AREA /LEAVING
ELEVATED VALUES IN THE HIGHER TERRAIN UPSLOPE LOCATIONS OF NORTHERN
MARICOPA/LA PAZ/GILA COUNTIES/ AND HOLD BACK FROM ANY FLOOD WATCHES.
AS THE FLOW REORIENTS OUT OF THE SOUTHWEST MONDAY
AFTERNOON...SHOWERS SHOULD BECOME MORE ORGANIZED ESPECIALLY NORTH OF
PHOENIX. WILL RETAIN LIKELY POPS FOR MOST OF THE AREA MONDAY
AFTERNOON.
&&
.PREVIOUS DISCUSSION...
ANOTHER GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS WILL OCCUR TUESDAY
INTO TUESDAY NIGHT AS THE UPPER TROF MOVES INLAND AND ACROSS THE
DESERT SOUTHWEST. AS THIS OCCURS...IT EJECTS THE REMNANTS OF NORBERT
INTO THE DESERTS OF SERN CA AND ARIZONA...AND ADDS A HEALTHY SHOT OF
DYNAMICS IN THE FORM OF PVA/Q CONVERGENCE. BY FAR THE STRONGEST QG
FORCING IS ADVERTISED TO MOVE OVER THE LOWER DESERTS DURING THIS
PERIOD. DUE TO A MUCH COOLER BOUNDARY LAYER...INSTABILITY WILL BE
REDUCED...AND FORECAST CAPE VALUES FOR TUESDAY ARE ON THE SMALL
SIDE. STILL...WITH PWAT VALUES OVER THE DESERTS STILL IN EXCESS OF
1.5 INCHES THERE EXISTS THE THREAT OF HEAVY RAIN YET AGAIN AND WE
AGAIN RAISED OUR POPS INTO THE CHANCE CATEGORY OVER MOST OF THE CWA.
HIGH TEMPS WILL REMAIN WELL BELOW SEASONAL NORMALS WITH MOST OF THE
DESERTS FORECAST TO STAY IN THE LOW TO MID 90S.
ON WEDNESDAY MOST OF THE ENERGY ASSOCIATED WITH THE TROF WILL LIFT
OFF TO THE NORTHEAST...HOWEVER BAGGY TROFFING STILL EXISTS OVER
ARIZONA AND THERE WILL BE QUITE A BIT OF LINGERING MOISTURE. GFS
AGAIN CALLS FOR PWAT VALUES OVER 1.5 INCHES OVER THE CENTRAL
DESERTS...WITH 850MB DEWPOINTS IN EXCESS OF 12C OVER MOST OF THE
CWA. INSTABILITY WILL BE LIMITED DUE TO CONTINUED COOL HIGH TEMPS
BUT WE WILL SEE A CONTINUED THREAT OF INSTABILITY SHOWERS OR
THUNDERSTORMS OVER MOST OF THE LOWER AZ DESERTS. RAISED POPS INTO
THE SLIGHT CHANCE CATEGORY ACROSS MOST AREAS TO THE EAST OF THE
LOWER CO RIVER VALLEY.
FOR THURSDAY INTO THE WEEKEND...A GRADUAL DRYING AND WARMING TREND
IS BEING CALLED FOR AS HIGH PRESSURE ALOFT BUILDS ACROSS THE AREA
FROM THE WEST AND STEERING FLOW IS WEAK AND FAVORS THE SOUTHWEST.
EXPECT HIGH TEMPS NEAR SEASONAL NORMALS BY THE WEEKEND WITH POPS
MOSTLY IN THE SINGLE DIGITS.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
GOING TO CONTINUE WITH THE IDEA OF SHOWERS ACROSS THE METRO AROUND
12Z BUT BACK OFF A LITTLE BIT AND ONLY GO WITH VCSH AT ALL PHOENIX
SITES. SHOWERS WILL BE HIT OR MISS WITH CIGS GETTING DOWN TO AROUND
5000FT AT TIMES. AFTERNOON SHOWERS ARE MOST LIKELY NORTH OF PHOENIX
BUT COULD CREEP BACK INTO THE METRO. UNFORTUNATELY GIVEN THE
COMPLICATED SITUATION...LOW CONFIDENCE IN THE EXACT PLACEMENT OF
STORMS MONDAY AFTERNOON.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SHOWERS APPEAR TO BE DONE FOR THE EVENING ACROSS SOUTHEAST
CALIFORNIA AS LARGE SCALE SUBSIDENCE BEHIND THE NW AZ CONVECTION HAS
ESSENTIALLY SQUASHED ANY NEW STORMS FROM DEVELOPING. SHOWERS COULD
SNEAK BACK INTO BLH MONDAY AFTERNOON BUT UNTIL THEN BOTH SE CA SITES
SHOULD REMAIN DRY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY.
A GRADUAL DRYING TREND WILL COMMENCE DURING THE MIDDLE OF THE WEEK
AS MOISTURE GETS SCOURED OUT FROM THE NORTHWEST. ANY SHOWER AND
THUNDERSTORM CHANCES WOULD BE VERY SLIGHT...AND PRIMARILY LIMITED TO
THE HIGHER TERRAIN OF GILA COUNTY DURING THE AFTERNOON AND EARLY
EVENING HOURS. AFTERNOON HUMIDITY LEVELS WILL GENERALLY FALL INTO A
15-30 PERCENT RANGE WITH GOOD TO EXCELLENT OVERNIGHT RECOVERY. ASIDE
FROM SOME AFTERNOON UPSLOPE GUSTINESS...WIND SPEEDS WILL REMAIN
RELATIVELY LIGHT.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/DEWEY/CB
AVIATION...LEINS
FIRE WEATHER...MO
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
515 PM MST SUN SEP 7 2014
.SYNOPSIS...
MOISTURE WILL REMAIN IN PLACE ACROSS THE REGION FOR THE NEXT SEVERAL
DAYS AS FORMER HURRICANE NORBERT APPROACHES THE SOUTHERN CALIFORNIA
COAST. SHOWERS AND THUNDERSTORMS ARE EXPECTED AT TIMES THROUGH
TUESDAY...WITH SOME LOCATIONS POSSIBLY SEEING BRIEF PERIODS OF HEAVY
RAIN. A GRADUAL DRYING TREND IS EXPECTED TO BEGIN BY THE MIDDLE OF
THE WEEK AS HIGH PRESSURE SLOWLY REBUILDS OVER THE REGION.
&&
.DISCUSSION...
MID AFTERNOON SATELLITE IMAGERY AND RADAR TRENDS CONTINUE TO
INDICATE THE BULK OF THE CONVECTION IS POSITIONED ACROSS NW AZ AND
SOUTHERN NEVADA AS OF 00Z. THIS IS IN THE AREA OF MOST FAVORABLE
UPPER DIVERGENCE AND IS ALSO CO-LOCATED WITH THE AXIS OF 1.7 TO 1.9
INCH PWATS. SOME WEAK PULSE STORMS HAVE DEVELOPED ACROSS SOUTHERN
ARIZONA ALONG THE INTERNATIONAL BORDER BUT THESE HAVE BEEN SHORT
LIVED AND RELATIVELY WEAK IN NATURE. MEANWHILE ACROSS SOUTHEAST
ARIZONA...CU ARE STRUGGLING TO HANG ON AS DAYTIME HEATING IS QUICKLY
RUNNING OUT.
THE HI-RES GUIDANCE CONTINUES TO INDICATE THE MAJORITY OF THE
ACTIVITY TO THE NORTHWEST OF THE FORECAST AREA THIS EVENING...WITH A
LARGELY QUIET PERIOD OF WEATHER THROUGH 06Z ACROSS THE PHOENIX
METRO. HRRR AND OTHER HI-RES MODELS SUGGEST A WEAK UPPER TROUGH WILL
INITIATE STORMS LATE TONIGHT /AROUND MIDNIGHT/ OVER THE PHOENIX AREA
WHICH WILL PERSIST INTO MONDAY MORNING. I AM GOING TO REDUCE THE
POPS FOR THE EVENING /20-30 PERCENT ACROSS THE METRO/ AND FOCUS THE
HIGHEST CHANCES IN THE 06Z-18Z TIME FRAME. COULD CERTAINLY SEE SOME
STORMS THIS EVENING AROUND PHOENIX BUT THE COVERAGE SHOULD EXPAND
GREATLY LATE TONIGHT.
&&
.PREVIOUS DISCUSSION...
LATE THIS EVENING MORE CONVECTION IS EXPECTED FROM THE INTERNATIONAL
BORDER NORTHWESTWARD TO YAVAPAI COUNTY WHERE AN AXIS OF MID TO UPPER
LEVEL COLUMN STRETCHING LIES. DECENT DAY TIME HEATING HAS ALLOWED
ENOUGH INSTABILITY TO BE IN PLACE WITH A MORE SOUTHERLY STEERING
FLOW. BY LATE TONIGHT /AROUND 06Z MONDAY/ STEERING FLOW WILL BEGIN
TO SWING TO A MORE SOUTH-SOUTHWESTERLY DIRECTION AS THE TROPICAL
STORM MIGRATES NORTHWARD. THIS WIND SHIFT WILL AID IN THE OROGRAPHIC
AND DYNAMIC LIFT NEEDED FOR FURTHER DEVELOPMENT. DEEP MOISTURE
CONTINUES IN PLACE WITH MIXING RATIOS 13-15 G/KG AND PWAT VALUES
APPROACHING 2 INCHES. ALL OF THE MESOSCALE FORECAST MODELS HAVE COME
TO GOOD AGREEMENT IN SOLUTIONS FOR INITIATION AND STORM TRACKS
OVERNIGHT AND THROUGH MONDAY FOR WIDESPREAD COVERAGE ACROSS CENTRAL
ARIZONA AND PROGRESSING NORTH-NORTHEAST.
ANOTHER GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS WILL OCCUR TUESDAY
INTO TUESDAY NIGHT AS THE UPPER TROF MOVES INLAND AND ACROSS THE
DESERT SOUTHWEST. AS THIS OCCURS...IT EJECTS THE REMNANTS OF NORBERT
INTO THE DESERTS OF SERN CA AND ARIZONA...AND ADDS A HEALTHY SHOT OF
DYNAMICS IN THE FORM OF PVA/Q CONVERGENCE. BY FAR THE STRONGEST QG
FORCING IS ADVERTISED TO MOVE OVER THE LOWER DESERTS DURING THIS
PERIOD. DUE TO A MUCH COOLER BOUNDARY LAYER...INSTABILITY WILL BE
REDUCED...AND FORECAST CAPE VALUES FOR TUESDAY ARE ON THE SMALL
SIDE. STILL...WITH PWAT VALUES OVER THE DESERTS STILL IN EXCESS OF
1.5 INCHES THERE EXISTS THE THREAT OF HEAVY RAIN YET AGAIN AND WE
AGAIN RAISED OUR POPS INTO THE CHANCE CATEGORY OVER MOST OF THE CWA.
HIGH TEMPS WILL REMAIN WELL BELOW SEASONAL NORMALS WITH MOST OF THE
DESERTS FORECAST TO STAY IN THE LOW TO MID 90S.
ON WEDNESDAY MOST OF THE ENERGY ASSOCIATED WITH THE TROF WILL LIFT
OFF TO THE NORTHEAST...HOWEVER BAGGY TROFFING STILL EXISTS OVER
ARIZONA AND THERE WILL BE QUITE A BIT OF LINGERING MOISTURE. GFS
AGAIN CALLS FOR PWAT VALUES OVER 1.5 INCHES OVER THE CENTRAL
DESERTS...WITH 850MB DEWPOINTS IN EXCESS OF 12C OVER MOST OF THE
CWA. INSTABILITY WILL BE LIMITED DUE TO CONTINUED COOL HIGH TEMPS
BUT WE WILL SEE A CONTINUED THREAT OF INSTABILITY SHOWERS OR
THUNDERSTORMS OVER MOST OF THE LOWER AZ DESERTS. RAISED POPS INTO
THE SLIGHT CHANCE CATEGORY ACROSS MOST AREAS TO THE EAST OF THE
LOWER CO RIVER VALLEY.
FOR THURSDAY INTO THE WEEKEND...A GRADUAL DRYING AND WARMING TREND
IS BEING CALLED FOR AS HIGH PRESSURE ALOFT BUILDS ACROSS THE AREA
FROM THE WEST AND STEERING FLOW IS WEAK AND FAVORS THE SOUTHWEST.
EXPECT HIGH TEMPS NEAR SEASONAL NORMALS BY THE WEEKEND WITH POPS
MOSTLY IN THE SINGLE DIGITS.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
STILL THINKING TS WILL REMAIN WELL WEST...NORTH...AND SOUTH OF
TERMINALS THROUGH THIS EVENING...THOUGH AN ISOLD STORM WITH OUTFLOW
WINDS COULD DEVELOP OR MOVE INTO THE PHOENIX AREA LATER THIS
EVENING...BUT CONFIDENCE IS VERY LOW AT THIS POINT. ENOUGH MODEL
EVIDENCE AND CONFIDENCE EXISTS TO INCLUDE A MVFR GROUPING WITH SHRA
EARLY MONDAY MORNING...THOUGH TIMING AND DURATION IS STILL A BIT
UNCERTAIN...BUT WANTED A MENTION FOR PLANNING PURPOSES (VERY OUTSIDE
CHANCE OF BRIEF IFR CONDITIONS). SOUTHERLY SFC WINDS WILL
OCCASIONALLY VARY BETWEEN A SOMEWHAT WESTERLY HEADING LATE THIS
AFTERNOON TO MORE EASTERLY LATE TONIGHT. WINDS MAY BECOME MORE
VARIABLE WITHIN SHRA LATE TONIGHT/MONDAY MORNING.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
WHILE SOME LINGERING SCT STORMS/REDEVELOPMENT ARE LIKELY THIS
AFTERNOON...COVERAGE ONLY JUSTIFIES A VICINITY MENTION AT THIS TIME.
MODEL OUTPUT SUGGESTS A PERIOD OF QUIET WEATHER LATER THIS
EVENING...HOWEVER SCT SHRA MAY REENTER THE REGION MONDAY MORNING
WITH SOME OUTSIDE CHANCE OF MVFR CONDITIONS (PRIMARILY NEAR KBLH).
HOWEVER...GIVEN THE MOIST ENVIRONMENT...SCT SHRA MAY BE POSSIBLE AT
JUST ABOUT ANY TIME THROUGH MONDAY AFTERNOON.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY.
A GRADUAL DRYING TREND WILL COMMENCE DURING THE MIDDLE OF THE WEEK
AS MOISTURE GETS SCOURED OUT FROM THE NORTHWEST. ANY SHOWER AND
THUNDERSTORM CHANCES WOULD BE VERY SLIGHT...AND PRIMARILY LIMITED TO
THE HIGHER TERRAIN OF GILA COUNTY DURING THE AFTERNOON AND EARLY
EVENING HOURS. AFTERNOON HUMIDITY LEVELS WILL GENERALLY FALL INTO A
15-30 PERCENT RANGE WITH GOOD TO EXCELLENT OVERNIGHT RECOVERY. ASIDE
FROM SOME AFTERNOON UPSLOPE GUSTINESS...WIND SPEEDS WILL REMAIN
RELATIVELY LIGHT.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/DEWEY/CB
AVIATION...MO
FIRE WEATHER...MO
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
832 AM PDT SAT SEP 6 2014
.SYNOPSIS...
SUBTROPICAL MOISTURE STREAMING NORTHWESTWARD OVER THE AREA WILL
BRING INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS. ISOLATED
ACTIVITY IS EXPECTED OVER THE MOUNTAINS THIS AFTERNOON...BECOMING
MORE WIDESPREAD ON SUNDAY AND MONDAY. THE BEST CHANCES WILL BE IN
THE MOUNTAINS AND DESERTS. A RICH MOISTURE SUPPLY WILL FUEL LOCALLY
HEAVY RAINFALL AMOUNTS AND POSSIBLE FLASH FLOODING NEAR THE
MOUNTAINS AND DESERTS. THE MONSOONAL FLOW WILL LIMIT THE MARINE
LAYER INFLUENCE UNTIL TUESDAY...WHEN A LOW PRESSURE TROUGH WILL DIG
DOWN THE WEST COAST WITH INCREASING ONSHORE FLOW. THE THREAT OF
SHOWERS WILL DIMINISH ON TUE...WITH DRY...SEASONAL WEATHER FOR THE
REMAINDER OF THE WEEK.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
VISIBLE SATELLITE IMAGERY EARLY THIS MORNING SHOWED THE LOWER CLOUDS
MUCH MORE LIMITED THAN THE PAST COUPLE OF MORNINGS. A FEW CLOUDS
WERE EVIDENT AROUND THE SALTON SEA...BUT MOST WERE HOVERING JUST
OFFSHORE. WINDS WERE MOSTLY LIGHT AND SURFACE PRESSURE GRADIENTS
WEAK...WITH A CONTINUED OFFSHORE TREND. BASED ON REMOTE OBSERVATIONS
AND GPS DATA WITH PW VALUES AROUND 1.4 INCHES...A RICH MOISTURE
SUPPLY EXISTS BELOW 4K FT IN THE LOWER DESERTS. THE 12Z MIRAMAR
SOUNDING HAD QUITE A JUMP THIS MORNING AS WELL...TO 1.3 INCHES. A 7
DEGREE C INVERSION WAS BASED NEAR 1150 FT...CONSIDERABLY LOWER THAN
YESTERDAY.
THE SHALLOWER MARINE LAYER AND PLENTY OF SUN TODAY WILL BOOST
TEMPERATURES WEST OF THE MOUNTAINS. MAX TEMPS IN THE INLAND EMPIRE
WILL FLIRT WITH TRIPLE DIGITS...AND INLAND SAN DIEGO WILL BE WELL
INTO THE 90S BY AFTERNOON. ALONG THE COAST...A WEAKER SEA BREEZE
WILL ALLOW TEMPERATURES TO CLIMB INTO THE UPPER 70S AND 80S. OVER
THE MOUNTAINS...HEATING SHOULD BE SUFFICIENT TO FIRE OFF CONVECTION
ALONG THE HIGHER PEAKS. SOME OF THIS COULD DRIFT ALONG THE COASTAL
FOOTHILLS AS WELL. THE LATEST RUN OF THE HIRES HRRR MODEL DOES
INDICATE SOME CONVECTION OVER THE HIGHER PEAKS BUT OTHER RECENT
MODEL RUNS ARE DRY.
HURRICANE NORBERT CONTINUES TO MOVE SLOWLY TOWARD THE NW...JUST OFF
THE PACIFIC COAST OF SOUTHERN BAJA. NORBERT STRENGTHENED TO A
CATEGORY 3 HURRICANE LATE FRIDAY EVENING...ACHIEVING MAJOR HURRICANE
STATUS. AT 8 AM PDT...HIGHEST SUSTAINED WINDS WERE 115 MPH.
WEAKENING IS EXPECTED TO COMMENCE LATER TODAY THROUGH MON AS NORBERT
MOVES OVER COOLER WATERS. THE REMNANTS ARE EXPECTED TO MOVE INLAND
ACROSS NORTHERN BAJA ON TUE...WITH THE VARIOUS MODELS NOW COMING
INTO BETTER AGREEMENT.
IN THE MEANTIME PW WILL CONTINUE TO INCREASE ACROSS THE REGION
THROUGH MON AS FLOW AROUND TROPICAL CYCLONE NORBERT TEAMS UP WITH
THE MOISTURE FROM FORMER ATLANTIC TROPICAL CYCLONE DOLLY. THE MAIN
CONCERN HERE IS WITH THE ANOMALOUSLY HIGH MOISTURE VALUES THAT WILL
BE PRESENT OVER THE AREA BY SUN/MON...PARTICULARLY RIVERSIDE AND SAN
DIEGO COUNTIES WITH VALUES FORECAST WELL IN EXCESS OF TWO INCHES.
THIS MOISTURE INFLUX WILL BRING GREATER CLOUD COVER FOR SUN/MON
WHICH WILL KEEP MAX TEMPS LOWER INLAND...BUT HUMIDITY WILL BE UP.
WITH THE LEADING EDGE OF THE MOISTURE INFLUX...SHOWERS AND ISOLATED
THUNDERSTORMS MAY DEVELOP LATE TONIGHT/SUN MORNING. THIS POSES A
QUESTION ABOUT THE EXTENT AND PERSISTENCE OF CLOUD COVER ON SUN.
THUNDERSTORM AND POSSIBLE MCS DEVELOPMENT LATER TODAY AND OVERNIGHT
OVER THE LOWER COLORADO RIVER VALLEY MAY PLAY A ROLE AS WELL.
WITHOUT AN OBVIOUS TRIGGER TO GENERATE THUNDERSTORMS...HEATING AND/
OR OUTFLOW BOUNDARIES FROM ACTIVITY TO THE EAST MAY BE NECESSARY TO
GET STRONG LIFT AND EXCESSIVE RAINFALL AMOUNTS. IN ANY CASE...SHOWER
CHANCES EXTEND ALL THE WAY TO THE COAST AS THE INFLUX OF MID-LEVEL
MOISTURE ARRIVES...EVEN THOUGH MODEL PRECIP AMOUNTS HAVE BEEN SPOTTY
AT BEST.
GIVEN THE EXCESSIVE MOISTURE SUPPLY...WHERE THUNDERSTORMS DO
DEVELOP...HEAVY RAINFALL AND FLASH FLOODING IS LIKELY TO FOLLOW.
ISOLATED RAINFALL AMOUNTS EXCEEDING 3 INCHES LOOK POSSIBLE. STEERING
LEVEL FLOW WILL BE RATHER WEAK...BUT MAINLY OUT OF THE SOUTH TO SE
FOR SUNDAY. DEPENDING ON LATER MODEL RUNS AND AVAILABLE
OBSERVATIONS...WE MAY NEED TO EXPAND THE FLASH FLOOD WATCH INTO THE
VALLEYS. PW VALUES CONTINUE EXCESSIVE ON MON...WITH SLIGHTLY BETTER
UPPER SUPPORT. DRYING WILL COMMENCE OVER NORTHERN PORTIONS OF THE
CWA ON MON NIGHT AS THE UPPER TROUGH SAGS SOUTH ACROSS THE STATE.
HOWEVER...HIGH PW VALUES ARE LIKELY TO PERSIST INTO TUE OVER
PORTIONS OF SAN DIEGO COUNTY.
DRY WEATHER AND SEASONAL TEMPERATURES ARE EXPECTED TO FOLLOW FOR THE
REMAINDER OF THE WEEK.
&&
.AVIATION...
061530Z...MOSTLY CLEAR THIS MORNING...EXCEPT FOR SOME PATCHY LOW
CLOUDS WITH BASES AROUND 1000 FT MSL OVER COASTAL SAN DIEGO COUNTY.
THESE CLOUDS SHOULD CLEAR BY 16Z. PATCHY LOW CLOUDS WITH BASES
AROUND 1000 FT MSL AND TOPS TO 1500 FT COULD RETURN TO THE COASTAL
AREAS AFT 06Z SUN...BUT ARE NOT LIKELY TO IMPACT TAF SITES WITH LOW
CIGS AND REDUCED VIS. OTHERWISE...CLEAR WITH UNRESTRICTED VIS THIS
MORNING BECOMING SCT 4000 FT MSL LAYERED TO 35000 FT THIS AFTERNOON.
MOUNTAINS/DESERTS...SCT CLOUDS WITH BASES 3000-4000 FT MSL THIS
MORNING IN THE COACHELLA VALLEY AND SAN DIEGO COUNTY DESERTS...
FOLLOWED BY A CHANCE OF SHOWERS AND THUNDERSTORMS WITH BASES
6000-8000 FT MSL LAYERED TO 35000-40000 FT AFT 18Z. THUNDERSTORMS
MAY PRODUCE GUSTY/ERRATIC DOWNDRAFT WINDS...SMALL HAIL AND LOCALLY
REDUCED VIS IN HEAVY RAIN. OTHERWISE...UNRESTRICTED VIS THROUGH THIS
EVENING.
&&
.MARINE...
830 AM...THERE IS A SLIGHT CHANCE OF THUNDERSTORMS OVER THE COASTAL
WATERS SUNDAY AND MONDAY FROM THE REMNANTS OF TROPICAL CYCLONE
NORBERT.
&&
.BEACHES...
830 AM...A LONG-PERIOD SOUTHWEST SWELL ORIGINATING IN THE SOUTHERN
HEMISPHERE WILL CONTINUE TO GENERATE ELEVATED SURF ON SOUTH AND
SOUTHWEST FACING BEACHES THROUGH TONIGHT. THIS SWELL WILL SUBSIDE
SUNDAY INTO MONDAY. HOWEVER...A 4-6 FOOT/9-12 SECOND SOUTH-SOUTHEAST
SWELL GENERATED BY TROPICAL CYCLONE NORBERT WILL LIKELY ARRIVE EARLY
SUNDAY MORNING AND CONTINUE THROUGH MONDAY. THE SURF HEIGHTS AND
LARGE TIDAL SWINGS WILL RESULT IN STRONG AND DANGEROUS RIP AND
LONGSHORE CURRENTS. THERE IS ALSO THE POTENTIAL FOR MINOR TIDAL
OVERFLOW DURING HIGH TIDES. A BEACH HAZARDS STATEMENT IS IN EFFECT
THROUGH MONDAY NIGHT...SEE LAXCFWSGX AND LAXSRFSGX FOR MORE DETAILS.
&&
.SKYWARN...
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH FROM SUNDAY MORNING THROUGH MONDAY EVENING
FOR THE APPLE AND LUCERNE VALLEYS...COACHELLA VALLEY...
RIVERSIDE COUNTY MOUNTAINS...SAN BERNARDINO COUNTY
MOUNTAINS...SAN DIEGO COUNTY DESERTS...SAN DIEGO COUNTY
MOUNTAINS.
BEACH HAZARDS STATEMENT THROUGH LATE MONDAY NIGHT FOR THE
BEACHES IN THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO
COUNTY COASTAL AREAS.
PZ...NONE.
&&
$$
PUBLIC...JAD
AVIATION/MARINE/BEACHES...PG
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1043 AM MDT SAT SEP 6 2014
.UPDATE...
ISSUED AT 940 AM MDT SAT SEP 6 2014
THE FOG IS DONE OR NEARLY SO AT THIS TIME...HOWEVER THERE IS A
STRATUS FIELDS STILL IN PLACE OVER SOME OF THE URBAN CORRIDOR AND
THE PALMER RIDGE. THE CEILINGS ARE COMING UP SLOWLY AND THERE IS
SOME EROSION OF THE FIELD. THE ACARS SOUNDINGS SHOW THE PLAINS TO
BE PRETTY STABLE...SO WILL NOT HAVE MANY POPS FOR THE THERE.
THERE IS SOME CONVECTIVE CLOUDINESS STARTING TO DEVELOP OVER THE
MOUNTAINS. WILL MAKE SOME MINOR ADJUSTMENTS IN CLOUDS. THE RAP AND
HRRR SHOWS VERY LITTLE CONVECTION IN THE MOUNTAINS THIS AFTERNOON
AND EVENING. MAY LOWER MOUNTAIN POPS A BIT AS WELL. WILL LEAVE
TEMPERATURES AS IS FOR NOW.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 345 AM MDT SAT SEP 6 2014
MUCH OF THE STRATUS HAS DISSIPATED OVER THE FRONT RANGE WHILE A
BATCH OF MID LEVEL CLOUDS CONTINUES TO STREAM OVER THE AREA.
TEMPERATURE AND DEWPOINT SPREADS ARE STILL LOW AND EXPECT ONCE
THIS MID LEVEL DECK PASSES THAT MORE FOG WILL DEVELOP THOUGH LOW
CONFIDENCE ON HOW EXTENSIVE IT WILL BECOME AFTER SUNRISE.
OVERALL MOISTURE LEVELS HAVE DROPPED A FEW TENTHS FROM YESTERDAY
BUT STILL EXPECT SCATTERED THUNDERSTORM ACTIVITY IN THE MOUNTAINS
AND FOOTHILLS WITH SOME MOISTURE CONVERGENCE AND SLIGHT
INSTABILITY. RIDGING ALOFT WILL BE BUILDING OVER COLORADO WITH
CONTINUED WEAK SUBSIDENCE. THERE IS LIGHTNING STILL ONGOING OVER
NRN UTAH SO SOME OF THIS WILL DRIFT INTO THE NORTHERN MOUNTAINS
THIS AFTERNOON. A FEW STORMS WILL DRIFT OVER THE URBAN CORRIDOR
AND PALMER DIVIDE. SURFACE BASED CAPES UNDER 500J/KG SO STORMS
WILL BE GENERALLY BE ON THE WEAK SIDE WITH BRIEF RAIN AND GUSTY
WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM MDT SAT SEP 6 2014
ON SUN THE FLOW ALOFT WILL BE WNW. THE ECMWF SHOWS SOME MID LVL
MOISTURE EMBEDDED IN THIS FLOW WILL THE GFS IS DRIER. AFTN CAPES
WILL RANGE FM 500-1000 J/KG MAINLY OVER NERN CO. WILL KEEP IN A
SLIGHT CHC OF AFTN/EVENING TSTMS OVER THE HIGHER TERRAIN AND ACROSS
THE PLAINS. AS FOR HIGHS WILL SEE 5 TO 6 DEGREES OF WARMING IN THE
850-700 MB LYR SO AFTN HIGHS SHOULD RISE INTO THE LOWER TO MID
80S OVER NERN CO.
ON MON THE FLOW ALOFT WILL BECOME MORE WSW AS SOME TROPICAL MOISTURE
FM NORBERT GETS ENTRAINED INTO THE MID LVL FLOW. THIS SHOULD LEAD
TO A BETTER CHC FOR SHOWERS AND STORMS OVER THE HIGHER TERRAIN WITH
SOME OF THIS ACTIVITY SPREADING ACROSS THE PLAINS MON NIGHT. HIGHS
ON MON WILL BE SIMILAR TO SUN WITH READINGS IN THE LOWER TO MID 80S
ACROSS THE PLAINS. FOR TUE INTO TUE NIGHT APPEARS A WK UPPER LEVEL
TROUGH WILL MOVE ACROSS THE AREA WHICH SHOULD ALLOW FOR A GOOD CHC
OF SHOWERS AND STORMS OVER THE HIGHER TERRAIN WITH A CHC OVER NERN
CO. AS FOR HIGHS READINGS MAY BE A FEW DEGREES COOLER OVER NERN CO
WITH TEMPS IN THE UPPER 70S TO LOWER 80S.
BY WED THE WK UPPER LEVEL TROUGH WILL MOVE EAST OF THE AREA WITH A
DRIER AIRMASS SPREADING INTO THE RGN. MEANWHILE A COLD FNT WILL
MOVE INTO NERN CO WHICH WILL DROP READINGS INTO THE LOWER TO MID
70S. OVERALL THE THREAT FOR TSTMS LOOKS LOWER ON WED DUE TO LESS
INSTABILITY AND A DRIER AIRMASS OVER THE AREA SO WILL ONLY MENTION
ISOLD TO WDLY SCT TSTMS.
FOR WED NIGHT INTO THU THE FLOW ALOFT WILL BE NWLY AS A STRONGER FNT
MOVES INTO NERN CO. WILL SEE INCREASING UPSLOPE FLOW AND IF THERE
IS A DISTURBANCE EMBEDDED IN THE FLOW THIS COULD LEAD TO A CHC OF
SHOWERS. TEMPS WILL BE COOLER ON THU WITH READINGS ONLY IN THE 60S
OVER NERN CO. IT COULD BE EVEN COLDER IF SKIES REMAIN OVERCAST ALL
DAY WHICH WOULD KEEP HIGHS ONLY IN THE 50S. BY FRI DRY NW FLOW
ALOFT WILL BE OVER THE AREA AS A SFC HIGH MOVES INTO THE CENTRAL
PLAINS. AFTN HIGHS WILL STILL REMAIN BLO NORMAL WITH HIGHS IN THE
65 TO 70 DEGREE RANGE OVER NERN CO.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z SUNDAY MORNING)
ISSUED AT 940 AM MDT SAT SEP 6 2014
SATELLITE PICTURES ARE SHOWING A STRATA-CUMULUS FIELD OVER THE
AIRPORT RIGHT NOW. THE CEILINGS SHOULD GO THE SCATTERED BY 18Z.
WINDS WILL E INSIGNIFICANT...UNDER 10 KNOTS AND LIKELY FROM THE
EAST UNTIL DRAINAGE KICKS IN THIS EVENING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RJK
SHORT TERM...ENTREKIN
LONG TERM...RPK
AVIATION...RJK
AREA FORECAST DISCUSSION
NWS ALBANY NY
146 AM EDT SAT SEP 6 2014
.SYNOPSIS...
A FLOW OF WARM AND HUMID SOUTHERLY AIR WILL CONTINUE TO RESULT IN
ABOVE NORMAL TEMPERATURES INTO SATURDAY. A COLD FRONT APPROACHING
FROM THE GREAT LAKES AND SOUTHEAST CANADA WILL CROSS OUR REGION ON
SATURDAY...BRINGING SHOWERS AND THUNDERSTORMS. SOME OF THE
THUNDERSTORMS MAY BE STRONG TO SEVERE. MUCH COOLER AND DRIER AIR
WILL MOVE IN FOR SUNDAY AND MONDAY...AS HIGH PRESSURE BUILDS IN FROM
THE WEST.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1215 AM EDT...A MUGGY EVENING CONTINUES WITH SOME HAZE AS
DEWPOINTS WERE HOVERING 70F AND WIDELY SCATTERED CLOUDS. STRATUS
HAS BECOME MORE PRONOUNCED INTO PORTIONS OF THE CATSKILLS...NW CT
AND SOUTHERN BERKS PER THE 11U-3.9U IMAGERY. THIS WILL LIKELY
SPREAD A BIT OVERNIGHT AS OUR REGION REMAINS FIRMLY ENTRENCHED IN
A WARM SECTOR AHEAD OF A COLD FRONT APPROACHING FROM THE GREAT
LAKES AS WELL AS A PRE FRONTAL TROUGH APPROACHING FROM WESTERN NEW
YORK. THE IMPRESSIVE LINE OF CONVECTION IN THE VICINITY OF THE
COLD FRONT WAS CROSSING LOWER ONTARIO PROVINCE AND IS NOW SHOWING
SIGNS OF WEAKENING.
THE LATEST MESOSCALE MODELS SUCH AS THE HRRR AND LOCAL HI RES WRF
INDICATING LINES/CLUSTERS OF CONVECTION WILL APPROACH CENTRAL NY
LATE THIS EVENING IT IS FORECAST TO WEAKEN FURTHER IN
INTENSITY...AND BY THE TIME IT POTENTIALLY REACHES EAST CENTRAL
NEW YORK LATE TONIGHT CONVECTION SHOULD DISSIPATE AS IT OUTRUNS
THE FORCING ASSOCIATED WITH THE FRONT. SO WILL ONLY MENTION SLIGHT
CHANCE TO LOW CHANCE POPS THROUGH THE NIGHT WEST OF THE CAPITAL
REGION...WITH THE HIGHER VALUES ACROSS THE WESTERN ADIRONDACKS AND
MOHAWK VALLEY. HIGHEST CONFIDENCE FOR AREAS FROM THE CAPITAL
REGION EASTWARD REMAINING RAIN-FREE THROUGH SUNRISE SATURDAY.
MINIMUM TEMPERATURES ONLY EXPECTED TO DROP INTO THE 60S REGION-WIDE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
SATURDAY LOOKS TO BE A CONVECTIVELY ACTIVE DAY ACROSS MUCH OF THE
AREA...AS A COLD FRONT SWEEPS FROM NORTHWEST TO SOUTHEAST DURING THE
DAY. IT WILL REMAIN QUITE HUMID...SO ANY BREAKS OF SUNSHINE EARLY
WILL LEAD TO RAPID DESTABILIZATION AHEAD OF THE COLD FRONT. THE BEST
CHANCE FOR SOME EARLY SUNSHINE WHERE FORECAST SBCAPE VALUES COULD
REACH 1500-2500 J/KG...IS FROM AROUND THE ALBANY AND SARATOGA
REGIONS SOUTH AND EAST. FLOW ALOFT WILL STEADILY INCREASE THROUGH
THE AFTERNOON...WHICH WILL ALLOW THE SHEAR TO STRENGTHEN AS WELL.
DEEP LAYER SHEAR OF 25-35 KT AND THE APPROACHING COLD FRONT WILL
LIKELY ALLOW FOR ORGANIZED CLUSTERS/BOWS TO DEVELOP...WITH DAMAGING
WINDS THE MAIN THREAT AS FAIRLY WEAK MID-LEVEL LAPSE RATES SHOULD
PRECLUDE A HAIL THREAT. EFFICIENT DOWNPOURS WILL ALSO BE POSSIBLE
WITH ANY STORMS. HOWEVER...GIVEN THE INCREASING FLOW AND RECENT DRY
GROUND CONDITIONS...WE ARE NOT EXPECTING HYDRO RELATED PROBLEMS
EXCEPT FOR ISOLATED MINOR URBAN/POOR DRAINAGE FLOODING POSSIBLE.
BASED ON TIMING FROM THE 12Z GUIDANCE SUITE AND LOCAL HI RES
WRF...TIMING FOR CONVECTION LOOKS TO BE LATE MORNING TO EARLY
AFTERNOON FOR AREAS NORTH AND WEST OF THE CAPITAL REGION...MID TO
LATE AFTERNOON FOR THE CAPITAL REGION...SARATOGA REGION...SOUTHERN
VERMONT AND THE CATSKILLS...AND LATE AFTERNOON TO EARLY EVENING FOR
THE MID HUDSON VALLEY...TACONICS AND BERKSHIRES/LITCHFIELD HILLS.
DUE TO THE TIMING...BEST CHANCES FOR SEVERE STORMS WILL BE FROM
CENTRAL MOHAWK VALLEY AND SARATOGA REGION SOUTH AND EAST. THIS
INCLUDES THE GREATER CAPITAL DISTRICT AND ALL POINTS SOUTH AND EAST.
WILL CONTINUE TO MENTION POTENTIAL FOR DAMAGING WINDS IN THE HWO FOR
THESE AREAS.
DUE TO THE COLD FRONT FRONT CROSSING THE REGION...MAXIMUM
TEMPERATURES WILL RANGE FROM LOWER TO MID 70S ACROSS THE
ADIRONDACKS...TO LOWER TO MID 80S FROM ALBANY SOUTH AND EAST. IT
WILL REMAIN HUMID FOR MUCH OF THE AREA FOR MOST OF THE DAY...WITH
DEWPOINTS SPIKING IN THE UPPER 60S TO LOWER 70S.
ANY LINES OF CONVECTION SHOULD BE EAST OF THE AREA BY DARK...WHICH
WILL END THE SEVERE THREAT. JUST A FEW LINGERING SHOWERS WILL BE
POSSIBLE FOR THE REST OF THE EVENING...ESPECIALLY ACROSS SOUTHERN
AREAS. COOLER AND DRIER AIR WILL FILTER INTO THE REGION OVERNIGHT
WITH A NORTHWEST BREEZE. TEMPERATURES WILL BE NOTICEABLY COOLER BY
EARLY SUNDAY MORNING.
DRY WEATHER AND SEASONABLY COOLER TEMPERATURES ALONG WITH PLENTY OF
SUNSHINE EXPECTED FOR SUNDAY AND MONDAY...AS HIGH PRESSURE BUILDS
EASTWARD AND SETTLES ACROSS THE NORTHEAST CONUS. HUMIDITY LEVELS
WILL BE QUITE COMFORTABLE...WITH COOL NIGHT TIME TEMPERATURES.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MONDAY NIGHT INTO TUESDAY...MOST OF THE REGION WILL SEE TRANQUIL
CONDITIONS WITH AVERAGE TEMPERATURES ACROSS THE REGION. 05/12Z MODEL
AND NUMERICAL GUIDANCE DOES SHOW A WEAK LOW PRESSURE SYSTEM WITH
TROPICAL ORIGINS MOVING SLOWLY UP THE EAST COAST. MOST OF THE REGION
NORTH OF THE LOWER MID HUDSON VALLEY WILL BE FAR ENOUGH REMOVED FROM
THE TRACK OF THIS COASTAL LOW. THIS WILL BRING SCATTERED CLOUD COVER
TO THE REGION BUT MOST REGIONS WILL REMAIN DRY WITH THE EXCEPTION OF
ISOLATED POPS ACROSS OUR FAR SOUTHEASTERN AREAS CLOSER TO THE CENTER
OF THE COASTAL LOW PRESSURE SYSTEM. HIGH TEMPERATURES ON TUESDAY
WILL RANGE FROM THE UPPER 60S IN THE HIGH TERRAIN TO LOWER AND MID
70S ACROSS VALLEY LOCATIONS.
TUESDAY NIGHT THROUGH FRIDAY...OUR NEXT WEATHER SYSTEM WILL BE
MAKING ITS WAY INTO THE REGION. MOST 12Z MODELS SHOW HIGHER
PROBABILITIES OF PRECIPITATION AS WE GO FROM THURSDAY INTO THURSDAY
EVENING. AS AN UPPER LEVEL LOW MOVES EQUATORWARD OUT OF CANADA AS WE
GO INTO THE DAY ON WEDNESDAY...A SERIES OF WEAK LOW PRESSURE
IMPULSES MOVING NORTHEASTWARD AROUND A BROAD 500 HPA CIRCULATION
OVER THE UPPER MIDWEST WILL PROVIDE ISOLATED TO SCATTERED SHOWERS
OVER OUR REGION...MAINLY DIURNALLY DRIVEN AS TEMPERATURES BEGIN TO
RISE INTO THE MID AND UPPER 70S ON WEDNESDAY WITH DEWPOINT
TEMPERATURES ON THE RISE AS WELL WITH A SOUTHERLY FLOW. AS WE GO
INTO THE DAY ON THURSDAY...THIS IS WHERE GLOBAL MODELS AND
PROBABILISTIC GUIDANCE DIVERGE IN CONFIDENCE FROM EACH OTHER. MODELS
RANGE FROM A CONTINUATION ON IMPULSES WHERE A WEAK SURFACE LOW MAY
DEVELOP JUST EAST OF OUR REGION THURSDAY AFTERNOON TO A MORE POTENT
SURFACE LOW DEVELOPMENT NEAR THE OHIO VALLEY UNDER A FAVORABLE
POSITION WITHIN A 100 KT JET STREAK PUTTING OUR REGION IN THE WARM
SECTOR FROM AN APPROACHING COLD FRONT AS WE GO INTO THURSDAY
EVENING. THIS FORECAST WILL BE UPDATED AS WE GET CLOSER TO THE EVENT
AND AS CONFIDENCE INCREASES. HIGH TEMPERATURES ON THURSDAY WILL
REMAIN NEAR AVERAGE ON THURSDAY. AS WE APPROACH THE END OF THE WEEK
ON FRIDAY...TRANQUIL WEATHER LOOKS TO RETURN TO THE REGION WITH
TEMPERATURES SLIGHTLY BELOW AVERAGE WITH A WEST TO NORTHWESTERLY
FLOW BEHIND THE PASSING COLD FRONT.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
THROUGH DAYBREAK...A COMPLEX SITUATION...AS THE REGION
REMAINS WITHIN THE WARM SECTOR OF A LOW PRESSURE SYSTEM CURRENTLY
ACROSS SOUTHERN CANADA...WITH A COLD FRONT APPROACHING FROM THE
GREAT LAKES REGION. LOW CLOUDS ARE EXPANDING NORTHWARD ACROSS
WESTERN NEW ENGLAND...WITH MVFR CIGS TRENDING TO IFR AT KPSF THROUGH
12Z/SAT. SOME OF THESE LOW CLOUDS ARE LIKELY TO EXPAND...OR REDEVELOP
FURTHER WEST INTO THE HUDSON RIVER VALLEY TOWARD 10Z/SAT. AT THIS
TIME...HAVE INDICATED MAINLY LOW MVFR CIGS...BUT A PERIOD OF IFR
CIGS CAN NOT BE RULED OUT AT KPOU/KALB/KGFL AFTER 10Z/SAT. SOME
SHOWERS...ASSOCIATED WITH REMNANT CONVECTION OVER WESTERN/CENTRAL
NYS MAY REACH KGFL AFTER 08Z/SAT.
AFTER DAYBREAK...MVFR/IFR CIGS SHOULD GRADUALLY LIFT BETWEEN
12Z-15Z/SAT...LAST AT KPSF. THEREAFTER...MAINLY VFR CONDITIONS ARE
EXPECTED THROUGH MOST OF THE DAY OUTSIDE OF SHOWERS AND
THUNDERSTORMS PRECEDING AND ACCOMPANYING THE COLD FRONTAL BOUNDARY.
THE COLD FRONT IS EXPECTED TO PASS THROUGH KGFL/KALB BETWEEN ROUGHLY
16Z-18Z/SAT...AND KPSF/KPOU BETWEEN ROUGHLY 18Z-22Z/SAT...LAST AT
KPOU. THE POSSIBILITY FOR EMBEDDED THUNDERSTORMS WILL BE GREATEST AT
KPSF AND KPOU...WHERE INSTABILITY WILL BE SOMEWHAT GREATER...SO HAVE
INCLUDED MENTION OF VCTS IN THESE LOCATIONS...WITH SHRA MENTIONED
ELSEWHERE...ALTHOUGH CAN NOT RULE OUT SOME THUNDER. AGAIN...BEST
CHANCE FOR SHOWERS AND POSSIBLE THUNDERSTORMS WILL BE WITH OR JUST
BEFORE THE COLD FRONT PASSES.
SOME LINGERING SHOWERS MAY OCCUR AT KPOU AND KPSF THROUGH EARLY
EVENING...OTHERWISE JUST SOME PATCHY MVFR CIGS ARE POSSIBLE THROUGH
MIDNIGHT...ESP AT KPSF.
WINDS WILL BE MAINLY FROM THE SOUTH TO SOUTHWEST AT 5-10 KT THROUGH
DAYBREAK...AND 8-12 KT AFTER DAYBREAK...BEFORE SHIFTING INTO THE
WEST...THEN NORTHWEST THIS AFTERNOON AT SIMILAR SPEEDS AS THE FRONT
MOVES THROUGH. WEST TO NORTHWEST WINDS WILL PERSIST AT 5-10 KT SAT
NT. WINDS WILL BE VARIABLE IN DIRECTION...AND MUCH STRONGER IN AND
NEAR ANY THUNDERSTORMS.
LOW LEVEL WIND SHEAR WILL BE POSSIBLE THROUGH DAYBREAK AT
KGFL...WHERE SFC WINDS WILL REMAIN LIGHTER...WHILE WINDS AROUND 2000
FT AGL WILL BE MAINLY SOUTHWEST AT 30-35 KT.
OUTLOOK...
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SUNDAY TO MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY TO TUESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE
OF SHRA.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
&&
.FIRE WEATHER...
A FLOW OF WARM AND HUMID SOUTHERLY AIR WILL CONTINUE TO RESULT IN
ABOVE NORMAL TEMPERATURES INTO SATURDAY. A COLD FRONT APPROACHING
FROM THE GREAT LAKES AND SOUTHEAST CANADA WILL CROSS OUR REGION ON
SATURDAY...BRINGING SHOWERS AND THUNDERSTORMS. SOME OF THE
THUNDERSTORMS MAY BE STRONG TO SEVERE. MUCH COOLER AND DRIER AIR
WILL MOVE IN FOR SUNDAY AND MONDAY...AS HIGH PRESSURE BUILDS IN FROM
THE WEST.
RELATIVE HUMIDITY VALUES WILL INCREASE TO AROUND 90 TO 100 PERCENT
TONIGHT...THEN DROP TO MINIMUM VALUES OF BETWEEN 55 AND 65 PERCENT
SATURDAY AFTERNOON. MAXIMUM RH VALUES SATURDAY NIGHT ARE EXPECTED TO
BE AROUND 90 TO 100 PERCENT.
WINDS TONIGHT ARE EXPECTED TO BE SOUTHERLY AROUND 5 TO 10 MPH.
SOUTHERLY WINDS WILL SHIFT TO THE WEST BEHIND A COLD FRONT SATURDAY
AFTERNOON. WINDS WILL BECOME NORTHWESTERLY AROUND 5 TO 10 MPH
SATURDAY NIGHT.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH AT LEAST THE NEXT
5 DAYS.
SHOWERS AND THUNDERSTORMS WILL DEVELOP AND OVERSPREAD THE AREA FROM
NORTHWEST TO SOUTHEAST ON SATURDAY AHEAD OF A COLD FRONT. WHILE
BASIN AVERAGE RAINFALL AMOUNTS LOOK TO BE UNDER A HALF
INCH...LOCALIZED RAINFALL AMOUNTS OF OVER 2 INCHES ARE POSSIBLE
WHICH MAY CAUSE ISOLATED MINOR FLOODING OF URBAN/POOR DRAINAGE
AREAS.
DRIER WEATHER IS THEN EXPECTED SATURDAY NIGHT THROUGH TUESDAY...AS
HIGH PRESSURE ASSOCIATED WITH RELATIVELY COOL AIR SETTLES OVER THE
REGION.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...JPV
NEAR TERM...BGM/11/JPV
SHORT TERM...JPV
LONG TERM...IAA/LFM
AVIATION...KL
FIRE WEATHER...JPV
HYDROLOGY...11/JPV
AREA FORECAST DISCUSSION
NWS ALBANY NY
1217 AM EDT SAT SEP 6 2014
.SYNOPSIS...
A FLOW OF WARM AND HUMID SOUTHERLY AIR WILL CONTINUE TO RESULT IN
ABOVE NORMAL TEMPERATURES INTO SATURDAY. A COLD FRONT APPROACHING
FROM THE GREAT LAKES AND SOUTHEAST CANADA WILL CROSS OUR REGION ON
SATURDAY...BRINGING SHOWERS AND THUNDERSTORMS. SOME OF THE
THUNDERSTORMS MAY BE STRONG TO SEVERE. MUCH COOLER AND DRIER AIR
WILL MOVE IN FOR SUNDAY AND MONDAY...AS HIGH PRESSURE BUILDS IN FROM
THE WEST.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1215 AM EDT...A MUGGY EVENING CONTINUES WITH SOME HAZE AS
DEWPOINTS WERE HOVERING 70F AND WIDELY SCATTERED CLOUDS. STRATUS
HAS BECOME MORE PRONOUNCED INTO PORTIONS OF THE CATSKILLS...NW CT
AND SOUTHERN BERKS PER THE 11U-3.9U IMAGERY. THIS WILL LIKELY
SPREAD A BIT OVERNIGHT AS OUR REGION REMAINS FIRMLY ENTRENCHED IN
A WARM SECTOR AHEAD OF A COLD FRONT APPROACHING FROM THE GREAT
LAKES AS WELL AS A PRE FRONTAL TROUGH APPROACHING FROM WESTERN NEW
YORK. THE IMPRESSIVE LINE OF CONVECTION IN THE VICINITY OF THE
COLD FRONT WAS CROSSING LOWER ONTARIO PROVINCE AND IS NOW SHOWING
SIGNS OF WEAKENING.
THE LATEST MESOSCALE MODELS SUCH AS THE HRRR AND LOCAL HI RES WRF
INDICATING LINES/CLUSTERS OF CONVECTION WILL APPROACH CENTRAL NY
LATE THIS EVENING IT IS FORECAST TO WEAKEN FURTHER IN
INTENSITY...AND BY THE TIME IT POTENTIALLY REACHES EAST CENTRAL
NEW YORK LATE TONIGHT CONVECTION SHOULD DISSIPATE AS IT OUTRUNS
THE FORCING ASSOCIATED WITH THE FRONT. SO WILL ONLY MENTION SLIGHT
CHANCE TO LOW CHANCE POPS THROUGH THE NIGHT WEST OF THE CAPITAL
REGION...WITH THE HIGHER VALUES ACROSS THE WESTERN ADIRONDACKS AND
MOHAWK VALLEY. HIGHEST CONFIDENCE FOR AREAS FROM THE CAPITAL
REGION EASTWARD REMAINING RAIN-FREE THROUGH SUNRISE SATURDAY.
MINIMUM TEMPERATURES ONLY EXPECTED TO DROP INTO THE 60S REGION-WIDE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
SATURDAY LOOKS TO BE A CONVECTIVELY ACTIVE DAY ACROSS MUCH OF THE
AREA...AS A COLD FRONT SWEEPS FROM NORTHWEST TO SOUTHEAST DURING THE
DAY. IT WILL REMAIN QUITE HUMID...SO ANY BREAKS OF SUNSHINE EARLY
WILL LEAD TO RAPID DESTABILIZATION AHEAD OF THE COLD FRONT. THE BEST
CHANCE FOR SOME EARLY SUNSHINE WHERE FORECAST SBCAPE VALUES COULD
REACH 1500-2500 J/KG...IS FROM AROUND THE ALBANY AND SARATOGA
REGIONS SOUTH AND EAST. FLOW ALOFT WILL STEADILY INCREASE THROUGH
THE AFTERNOON...WHICH WILL ALLOW THE SHEAR TO STRENGTHEN AS WELL.
DEEP LAYER SHEAR OF 25-35 KT AND THE APPROACHING COLD FRONT WILL
LIKELY ALLOW FOR ORGANIZED CLUSTERS/BOWS TO DEVELOP...WITH DAMAGING
WINDS THE MAIN THREAT AS FAIRLY WEAK MID-LEVEL LAPSE RATES SHOULD
PRECLUDE A HAIL THREAT. EFFICIENT DOWNPOURS WILL ALSO BE POSSIBLE
WITH ANY STORMS. HOWEVER...GIVEN THE INCREASING FLOW AND RECENT DRY
GROUND CONDITIONS...WE ARE NOT EXPECTING HYDRO RELATED PROBLEMS
EXCEPT FOR ISOLATED MINOR URBAN/POOR DRAINAGE FLOODING POSSIBLE.
BASED ON TIMING FROM THE 12Z GUIDANCE SUITE AND LOCAL HI RES
WRF...TIMING FOR CONVECTION LOOKS TO BE LATE MORNING TO EARLY
AFTERNOON FOR AREAS NORTH AND WEST OF THE CAPITAL REGION...MID TO
LATE AFTERNOON FOR THE CAPITAL REGION...SARATOGA REGION...SOUTHERN
VERMONT AND THE CATSKILLS...AND LATE AFTERNOON TO EARLY EVENING FOR
THE MID HUDSON VALLEY...TACONICS AND BERKSHIRES/LITCHFIELD HILLS.
DUE TO THE TIMING...BEST CHANCES FOR SEVERE STORMS WILL BE FROM
CENTRAL MOHAWK VALLEY AND SARATOGA REGION SOUTH AND EAST. THIS
INCLUDES THE GREATER CAPITAL DISTRICT AND ALL POINTS SOUTH AND EAST.
WILL CONTINUE TO MENTION POTENTIAL FOR DAMAGING WINDS IN THE HWO FOR
THESE AREAS.
DUE TO THE COLD FRONT FRONT CROSSING THE REGION...MAXIMUM
TEMPERATURES WILL RANGE FROM LOWER TO MID 70S ACROSS THE
ADIRONDACKS...TO LOWER TO MID 80S FROM ALBANY SOUTH AND EAST. IT
WILL REMAIN HUMID FOR MUCH OF THE AREA FOR MOST OF THE DAY...WITH
DEWPOINTS SPIKING IN THE UPPER 60S TO LOWER 70S.
ANY LINES OF CONVECTION SHOULD BE EAST OF THE AREA BY DARK...WHICH
WILL END THE SEVERE THREAT. JUST A FEW LINGERING SHOWERS WILL BE
POSSIBLE FOR THE REST OF THE EVENING...ESPECIALLY ACROSS SOUTHERN
AREAS. COOLER AND DRIER AIR WILL FILTER INTO THE REGION OVERNIGHT
WITH A NORTHWEST BREEZE. TEMPERATURES WILL BE NOTICEABLY COOLER BY
EARLY SUNDAY MORNING.
DRY WEATHER AND SEASONABLY COOLER TEMPERATURES ALONG WITH PLENTY OF
SUNSHINE EXPECTED FOR SUNDAY AND MONDAY...AS HIGH PRESSURE BUILDS
EASTWARD AND SETTLES ACROSS THE NORTHEAST CONUS. HUMIDITY LEVELS
WILL BE QUITE COMFORTABLE...WITH COOL NIGHT TIME TEMPERATURES.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MONDAY NIGHT INTO TUESDAY...MOST OF THE REGION WILL SEE TRANQUIL
CONDITIONS WITH AVERAGE TEMPERATURES ACROSS THE REGION. 05/12Z MODEL
AND NUMERICAL GUIDANCE DOES SHOW A WEAK LOW PRESSURE SYSTEM WITH
TROPICAL ORIGINS MOVING SLOWLY UP THE EAST COAST. MOST OF THE REGION
NORTH OF THE LOWER MID HUDSON VALLEY WILL BE FAR ENOUGH REMOVED FROM
THE TRACK OF THIS COASTAL LOW. THIS WILL BRING SCATTERED CLOUD COVER
TO THE REGION BUT MOST REGIONS WILL REMAIN DRY WITH THE EXCEPTION OF
ISOLATED POPS ACROSS OUR FAR SOUTHEASTERN AREAS CLOSER TO THE CENTER
OF THE COASTAL LOW PRESSURE SYSTEM. HIGH TEMPERATURES ON TUESDAY
WILL RANGE FROM THE UPPER 60S IN THE HIGH TERRAIN TO LOWER AND MID
70S ACROSS VALLEY LOCATIONS.
TUESDAY NIGHT THROUGH FRIDAY...OUR NEXT WEATHER SYSTEM WILL BE
MAKING ITS WAY INTO THE REGION. MOST 12Z MODELS SHOW HIGHER
PROBABILITIES OF PRECIPITATION AS WE GO FROM THURSDAY INTO THURSDAY
EVENING. AS AN UPPER LEVEL LOW MOVES EQUATORWARD OUT OF CANADA AS WE
GO INTO THE DAY ON WEDNESDAY...A SERIES OF WEAK LOW PRESSURE
IMPULSES MOVING NORTHEASTWARD AROUND A BROAD 500 HPA CIRCULATION
OVER THE UPPER MIDWEST WILL PROVIDE ISOLATED TO SCATTERED SHOWERS
OVER OUR REGION...MAINLY DIURNALLY DRIVEN AS TEMPERATURES BEGIN TO
RISE INTO THE MID AND UPPER 70S ON WEDNESDAY WITH DEWPOINT
TEMPERATURES ON THE RISE AS WELL WITH A SOUTHERLY FLOW. AS WE GO
INTO THE DAY ON THURSDAY...THIS IS WHERE GLOBAL MODELS AND
PROBABILISTIC GUIDANCE DIVERGE IN CONFIDENCE FROM EACH OTHER. MODELS
RANGE FROM A CONTINUATION ON IMPULSES WHERE A WEAK SURFACE LOW MAY
DEVELOP JUST EAST OF OUR REGION THURSDAY AFTERNOON TO A MORE POTENT
SURFACE LOW DEVELOPMENT NEAR THE OHIO VALLEY UNDER A FAVORABLE
POSITION WITHIN A 100 KT JET STREAK PUTTING OUR REGION IN THE WARM
SECTOR FROM AN APPROACHING COLD FRONT AS WE GO INTO THURSDAY
EVENING. THIS FORECAST WILL BE UPDATED AS WE GET CLOSER TO THE EVENT
AND AS CONFIDENCE INCREASES. HIGH TEMPERATURES ON THURSDAY WILL
REMAIN NEAR AVERAGE ON THURSDAY. AS WE APPROACH THE END OF THE WEEK
ON FRIDAY...TRANQUIL WEATHER LOOKS TO RETURN TO THE REGION WITH
TEMPERATURES SLIGHTLY BELOW AVERAGE WITH A WEST TO NORTHWESTERLY
FLOW BEHIND THE PASSING COLD FRONT.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS THIS EVENING WITH A LIGHT WIND AT SPEEDS AROUND
10KTS OR LESS. AS DEWPOINTS ARE RATHER HIGH...NEAR 70F...AND
NOCTURNAL COOLING OF THE BOUNDARY LAYER WE SHOULD SEE HAZE/MIST
DEVELOP TONIGHT. LATER OVERNIGHT...LOWER LEVEL STRATUS SHOULD
RESULT IN MORE MVFR CONDITIONS FOR CIGS/VIS. COULD NOT RULE OUT A
PERIOD OF IFR CONDITIONS AT KGFL-KPSF.
AS UPSTREAM COLD FRONT APPROACHES...THE PROBABILITIES FOR
CONVECTION IMPACTING FLIGHT CONDITIONS INCREASES. WE WILL CONTINUE
TO SHOW A GRADUATED APPROACH TO THE POPS WITH INITIALLY PROB30/S
THEN TEMPO GROUPS WITH THE DEEPER CONVECTION. WINDS WILL GENERALLY
BE FROM THE SOUTHWEST AROUND 10KTS WITH HIGHER GUSTS POSSIBLE IN
THE VICINITY OF CONVECTION.
OUTLOOK...
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SUNDAY TO MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY TO TUESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE
OF SHRA.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
&&
.FIRE WEATHER...
A FLOW OF WARM AND HUMID SOUTHERLY AIR WILL CONTINUE TO RESULT IN
ABOVE NORMAL TEMPERATURES INTO SATURDAY. A COLD FRONT APPROACHING
FROM THE GREAT LAKES AND SOUTHEAST CANADA WILL CROSS OUR REGION ON
SATURDAY...BRINGING SHOWERS AND THUNDERSTORMS. SOME OF THE
THUNDERSTORMS MAY BE STRONG TO SEVERE. MUCH COOLER AND DRIER AIR
WILL MOVE IN FOR SUNDAY AND MONDAY...AS HIGH PRESSURE BUILDS IN FROM
THE WEST.
RELATIVE HUMIDITY VALUES WILL INCREASE TO AROUND 90 TO 100 PERCENT
TONIGHT...THEN DROP TO MINIMUM VALUES OF BETWEEN 55 AND 65 PERCENT
SATURDAY AFTERNOON. MAXIMUM RH VALUES SATURDAY NIGHT ARE EXPECTED TO
BE AROUND 90 TO 100 PERCENT.
WINDS TONIGHT ARE EXPECTED TO BE SOUTHERLY AROUND 5 TO 10 MPH.
SOUTHERLY WINDS WILL SHIFT TO THE WEST BEHIND A COLD FRONT SATURDAY
AFTERNOON. WINDS WILL BECOME NORTHWESTERLY AROUND 5 TO 10 MPH
SATURDAY NIGHT.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH AT LEAST THE NEXT
5 DAYS.
SHOWERS AND THUNDERSTORMS WILL DEVELOP AND OVERSPREAD THE AREA FROM
NORTHWEST TO SOUTHEAST ON SATURDAY AHEAD OF A COLD FRONT. WHILE
BASIN AVERAGE RAINFALL AMOUNTS LOOK TO BE UNDER A HALF
INCH...LOCALIZED RAINFALL AMOUNTS OF OVER 2 INCHES ARE POSSIBLE
WHICH MAY CAUSE ISOLATED MINOR FLOODING OF URBAN/POOR DRAINAGE
AREAS.
DRIER WEATHER IS THEN EXPECTED SATURDAY NIGHT THROUGH TUESDAY...AS
HIGH PRESSURE ASSOCIATED WITH RELATIVELY COOL AIR SETTLES OVER THE
REGION.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...JPV
NEAR TERM...BGM/11/JPV
SHORT TERM...JPV
LONG TERM...IAA/LFM
AVIATION...IAA/BGM
FIRE WEATHER...JPV
HYDROLOGY...11/JPV
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1217 PM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT CROSSING OHIO IS POISED TO MOVE THROUGH OUR REGION THIS
EVENING...STALLING OFFSHORE THROUGH MID-WEEK... WHILE HIGH PRESSURE
IN THE CENTRAL PLAINS SPREADS TO OUR NORTH. LOW PRESSURE IN SOUTH
CAROLINA SUNDAY WILL DEVELOP NORTHEASTWARD OFF THE MID ATLANTIC
COAST LATE TUESDAY AND BE POSITIONED EAST OF CAPE COD BY LATE
WEDNESDAY. ANOTHER COLD FRONT WILL MOVE EASTWARD THROUGH OUR REGION
LATE THURSDAY OR FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW CLOUDS HAVE DISSIPATED BUT AN ABUNDANCE OF HIGH CLOUDS WITH
SOME MID CLOUDS WAS EVIDENT ON STLT IMAGERY OVER PA. THESE CLOUDS
WERE MOVG EWD. LTST RADAR IMAGERY STILL HAD NOTHING, PSBLY AS A
RESULT OF THE EARLIER LOW CLOUDS. HRRR ALREADY HAD PRECIP OVER OUR
NWRN AREAS, WHICH IS NOT THERE. SO, HAVE BACKED PRECIP UP A FEW
MORE HOURS AND LOWERED POPS IN THE REAL NEAR TERM AS WELL.
OTHERWISE, MADE SOME ADJUSTMENTS TO CLOUD COVER. TEMPS GENLY
LOOKED GOOD.
OVERALL FOR TODAY WE ARE EXPECTING AN INCREASE IN SHOWER AND
THUNDERSTORM ACTIVITY BY THE LATE AFTERNOON/EARLY EVENING TIMEFRAME.
THE COLD FRONT DRUDGING THROUGH THE GREAT LAKES AT THIS TIME WILL
BEGIN TO SLOW ITS SOUTHEAST PROGRESSION JUST A BIT THIS AFTERNOON AS
THE MID-LEVEL FLOW FLATTENS OUT SOME. AMPLE MOISTURE AND INSTABILITY
AHEAD OF THE FRONT WILL ALLOW FOR RAPID STORM GROWTH. MODEST
MID-LEVEL LAPSE RATES AND SHEAR WILL BE AN ISSUE FOR BETTER
ORGANIZATION OF CELLS THOUGH WITH THE HIGH PWAT AIR IN PLACE, RAIN
LOADED CORES CAN DROP AND PRODUCE GUSTY, POSSIBLY DAMAGING WINDS
THIS AFTERNOON. BETTER SHEAR PROFILES EXIST TO OUR NORTHEAST WHERE
STRONGER WINDS ALOFT ARE. SPC CONTINUES THE SLIGHT RISK FOR OUR
NORTHERN ZONES WHERE BETTER ORGANIZATION MAY EXIST, THOUGH JUST
ABOUT ANYWHERE IN OUR CWA COULD SEE PULSE STRONG TO SEVERE WIND
GUSTS.
THE GFS DID SLIGHTLY BETTER THAN THE NAM IN THE THERMAL
INITIALIZATION DEPARTMENT THIS MORNING.TEMPERATURES TODAY WERE A
BLEND OF THE MET/MAVMOS WITH A SLIGHT HEAVIER WEIGHING ON THE MAV.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
CONTINUED SHOWERY ACTIVITY WITH EMBEDDED CONVECTION WILL PUSH
SOUTHEAST ALONG THE COLD FRONT LATE THIS EVENING. HEAVY RAIN WITH
THE SHOWERS WILL REMAIN THE LARGEST THREAT THOUGH WE SHOULD HAVE
ENOUGH LINGERING LOW-LEVEL INSTABILITY TO SEE SOME STRONGER WIND
GUSTS WITH THE SHOWERS. WE SLOWED THE PROGRESSION OF THE DECREASING
POPS ACROSS OUR SOUTH JUST A BIT AS WE EXPECT THE FRONT TO SLOW SOME
DURING THE DAY. BEHIND THE FRONT NORTH-NORTHWEST WINDS WILL BRING IN
A MUCH DRIER AIRMASS AS DEWPOINTS ARE EXPECTED TO FALL INTO THE
MID-50S. THERE LOOKS TO BE TOO MUCH MIXING LATE TONIGHT TO ALLOW FOR
FOG FORMATION, EXCEPT WITHIN THE MORE SHELTERED RIVER VALLEYS. LOWS
TONIGHT WERE A BLEND OF THE MET/MAV WITH MORE WEIGHTING ON THE
SLIGHTLY WARMER MET WITH MORE MIXING TAKING PLACE.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
500 MB: HEIGHTS RISE/WARM WITH SHORT WAVE RIDGING FOLLOWING THE
DEPARTURE OF THE QUEBEC SHORT WAVE SUNDAY INTO MONDAY. THE NEXT
SHORT WAVE CROSSES THE MID ATLANTIC STATES LATE TUESDAY OR EARLY
WEDNESDAY. STRONG SHORT WAVES APPEAR LIKELY TO ROTATES NEWD
THROUGH THE GREAT LAKES REGION LATE IN THE WEEK...PRODUCING A
WARMING TREND ALONG THE MID ATLANTIC COAST.
TEMPERATURES: SEPTEMBER SO FAR (FIRST 5 DAYS) HAS AVERAGED WELL
ABOVE NORMAL....GENERALLY 6-7 DEGREES. THE DAILY AVERAGES WILL COOL
TO NEAR NORMAL SUNDAY-TUESDAY THEN WARM ABOVE NORMAL AGAIN
WEDNESDAY-FRIDAY. TEMPS MAY AVERAGE MORE THAN 5 DEGREES ABOVE
NORMAL THURSDAY AND FRIDAY.
FORECAST BASIS: UNLESS OTHERWISE NOTED THE LONG TERM PERIOD OF THIS
FORECAST IS GENERALLY BASED ON A 50 50 BLEND OF THE 00Z/6 NAM/GFS
MOS FOR THE PERIOD SUNDAY-MONDAY...THE 00Z/6 GFS MOS MONDAY NIGHT
AND TUESDAY...THEN THEREAFTER (TUESDAY NIGHT ONWARD) THE 0543Z/06
WPC GRIDDED GUIDANCE WHICH AT TIMES IS BLENDED 50 50 WITH THE
00Z/6 MEXMOS. ALL THIS IS EVENTUALLY CHECKED AGAINST THE 00Z/6
ECMWF TO SEE IF WE`RE IN THE BALLPARK WITH ECMWF CYCLICALLY
PERSISTENT 18Z 2 METER TEMPERATURES. THE PRECIPITATION PROBABILITY
GUIDANCE IS CHECKED AGAINST THE 21Z/5 SREF POPS FOR .01 IN 3 HRS
THROUGH 12Z TUESDAY AND THEREAFTER THE 00Z/6 GEFS 6HR POPS FOR
0.05
THE DAILIES BELOW...
SUNDAY...A VERY NICE DAY IN THE WAKE OF TODAYS SUMMERTIME HEAT.
MUCH LESS HUMID AND COOLER WITH PLENTY OF BRIGHT SUNSHINE. ANY
SHOWERS EARLY IN THE DAY ON THE SOUTHEAST EDGE OF OUR AREA SHOULD
END BY FORENOON.
MONDAY-TUESDAY...BECOMES PROBLEMATIC FROM SOUTH TO NORTH AS LOW
PRESSURE ALONG THE SOUTH CAROLINA COAST NEEDS TO BE MONITORED FOR
ITS FUTURE TRACK AND STRENGTHENING. AS IT STANDS NOW...A STIFF
EAST TO NORTHEAST OCEAN INFLOW SHOULD SPREAD CLOUDS AND THEN
SHOWERS OR BANDS OF RAIN NORTHWARD. DETAILS ON COVERAGE OF
SHOWERS AND AMOUNTS ARE STILL EARLY BUT THIS PERIOD OF TIME DESERVES
TO BE MONITORED AS A POTENTIALLY SIGNIFICANT EARLY SEPTEMBER
PERIOD OF NASTY WEATHER...AT LEAST ALONG THE COAST!
REGARDING THE LOW...PLEASE NOTE NHC HAS THIS AS A 10 TO 20 PCT
CHANCE OF TROPICAL CYCLONE FORMATION EARLY THIS COMING WEEK.
WED-FRI...TIMING DIFFERENCES BUT PULSES OF INSTABILITY BURSTS IN
RESPONSE TO STRONG SHORT WAVES ROTATING NEWD THROUGH THE GREAT LAKES
REGION OFFER CHANCE OF SHOWERS FROM TIME TO TIME BUT MOST OF THE
TIME SHOULD BE RAIN-FREE. WE TENDED TO RUN WARMER THAN THE 0543Z
WPC TEMPERATURE GUIDANCE...MORE IN LINE WITH THE WARMER 00Z/6 GFS
MEX MOS AND ECMWF 2M TEMPS.
AGAIN THE FOCUS THIS WEEK SHOULD BE ON MONDAY NIGHT-TUESDAY
EVENING FOR COASTAL NJ/DE RESIDENTS AND MARINERS.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE STUBBORN LOW CLOUDS FROM THIS MRNG HAVE DISSIPATED AND
EVERYONE IS NOW VFR. EXPECT VFR TO CONTINUE UNTIL ANY SHRA/TSRA
LATER. SOUTHWEST FLOW INCREASES WITH SOME GUSTS POSSIBLE. COLD
FRONT SLIDES IN FROM THE NORTHWEST TOUCHING OFF SHOWERS AND
THUNDERSTORMS DURG THE AFTN/EVE. LOOKS LIKE A GOOD CHANCE FOR WIDESPREAD
THUNDERSTORM ACTIVITY BY LATE AFTERNOON WITH BRIEF MVFR/IFR
RESTRICTIONS. CONTINUED SHOWER ACTIVITY POSSIBLE A FEW HOURS AFTER
FRONTAL PASSAGE.
TONIGHT...VFR. WINDS VEER TO THE NORTH-NORTHWEST BRINGING IN DRIER
AIR. SHOWERS CUT OFF BY LATE TONIGHT ACROSS THE SOUTHERN TERMINALS.
OUTLOOK...
SUNDAY...VFR. LIGHT NORTH WIND TRENDING EAST LATE DAY.
MONDAY - TUESDAY...VFR CIGS TO START MONDAY BUT PERIODS OF MVFR
CONDS EXPECTED IN BANDS OF SHOWERS AT LEAST ALONG THE COAST WHERE
BRIEF IFR CONDS MIGHT DEVELOP? E-NE WIND GUST 20-30 KT...HIGHEST
GUSTS COAST.
WEDNESDAY...MOSTLY VFR BUT LOCALLY MVFR/IFR IN SCATTERED SHOWERS
AND TSTMS LATE DAY OR AT NIGHT. LIGHT WIND BECOMING SOUTH.
&&
.MARINE...
SUB-SCA CONDITIONS ARE EXPECTED ACROSS OUR WATERS TODAY THOUGH WE
COULD SEE GUSTS UPWARDS OF 20 KNOTS BY THE AFTERNOON HOURS.
SOUTHWEST WINDS WILL VEER TOWARDS THE WEST-NORTHWEST LATE TONIGHT AS
A COLD FRONT PUSHES THROUGH. SEAS AHEAD OF THE FRONT WILL CLIMB TO
3-4 FEET BEFORE SUBSIDING A BIT BEHIND THE FRONT. GUSTY NORTHWEST
WINDS ARE POSSIBLE BEHIND THE FRONT...STILL AROUND 20 KNOTS
EXPECTED.
OUTLOOK...
SUNDAY...NO HEADLINE ANTICIPATED.
MONDAY AND TUESDAY...STRONG SCA EXPECTED EXCEPT A MORE MARGINAL
SCA POSSIBLE UPPER DELAWARE BAY. POTENTIAL FOR 35KT - GALE FORCE
GUSTS.
WEDNESDAY...SCA SEAS MAY LINGER ALONG THE ATLANTIC COASTAL WATERS
DURING THE MORNING DESPITE LIGHT WINDS. DE BAY SHOULD NOT NEED A A
MARINE HAZARD HEADLINE.
&&
.TIDES/COASTAL FLOODING...
FAIRLY STRONG AND LONG DURATION ONSHORE FLOW COMBINED WITH
ASTRONOMICALLY HIGH TIDE CYCLES AS WE MOVE THROUGH THE SEPTEMBER
SUPERMOON PHASE. SURGE OF A FOOT PROBABLE FOR THE MONDAY EVENING
AND TUESDAY HIGH TIDE CYCLES SHOULD RESULT IN 2 OR 3 TIDE CYCLES
WITH MINOR COASTAL FLOODING. NOT IMPOSSIBLE TO FORESEE SPOTTY
MODERATE COASTAL FLOODING BUT THAT MODERATE CF THREAT IS A MUCH A
LESSER CHANCE THAN THE MINOR EXCEEDENCES.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DRAG
NEAR TERM...HEAVENER/NIERENBERG
SHORT TERM...HEAVENER
LONG TERM...DRAG
AVIATION...DRAG/HEAVENER/NIERENBERG
MARINE...DRAG/HEAVENER
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
440 AM EDT SAT SEP 6 2014
...PERIODS OF HEAVY RAINFALL EXPECTED THROUGH MONDAY...
.CURRENTLY...
EARLY MORNING SURFACE ANALYSIS DEPICTS HIGH PRESSURE (1021
MILLIBARS) COVERING THE WESTERN ATLANTIC NORTH OF THE BAHAMAS. A
LOW-LEVEL TROUGH EXTENDS FROM THE GEORGIA COASTAL WATERS
SOUTHWESTWARD TO THE NORTHEAST GULF OF MEXICO. MEANWHILE...A COLD
FRONT IS PRESSING ACROSS THE GREAT LAKES STATES AND IS MOVING INTO
THE OHIO AND WESTERN PORTIONS OF THE TENNESSEE VALLEY REGION.
ALOFT...DEEP- LAYERED RIDGING IS CENTERED OFF THE CAROLINA
COASTLINE. LOW-TOPPED CONVECTION IS DEVELOPING ALONG THE LOW-
LEVEL TROUGH OVER THE OKEFENOKEE SWAMP AND THE SUWANNEE
VALLEY...WITH ISOLATED SHOWERS POPPING OVER THE REST OF NORTHEAST
FLORIDA. WITH WEAK STEERING FLOW IN PLACE...THIS ACTIVITY IS
MOVING VERY SLOWLY EASTWARD AND IS PRODUCING HEAVY RAINFALL
RATES...WHICH WILL LIKELY BE THE THEME FOR THE WEEKEND.
OTHERWISE...LOW CEILINGS AND ABUNDANT MID AND UPPER LEVEL CLOUDS
ARE BLANKETING MUCH OF THE REGION...WITH PATCHES OF FOG OVER
INTERIOR SOUTHEAST GA. TEMPERATURES AND DEWPOINTS AT 08Z WERE
GENERALLY IN THE LOW TO MID 70S REGION-WIDE.
.NEAR TERM (TODAY AND TONIGHT)...
SHORT-TERM HI-RESOLUTION GUIDANCE SUCH AS THE HRRR AND ARW HAVE
INITIALIZED WELL WITH RESPECT TO CONVECTIVE DEVELOPMENT IN THE
OKEFENOKEE/SUWANNEE VALLEY REGION...AND THESE MODELS ADVECT THIS
ACTIVITY INTO THE REMAINDER OF NORTHEAST AND NORTH CENTRAL FL
DURING THE REMAINDER OF THE MORNING HOURS. CYCLONIC FLOW IN THE
LOW LEVELS WILL CONTINUE TO PROVIDE ENOUGH FORCING FOR BANDS OF
SHOWERS AND THUNDERSTORMS TO DEVELOP INTO THE EVENING HOURS...WITH
ACTIVITY INCREASING IN COVERAGE ALONG THE I-95 CORRIDOR DURING THE
LATE AFTERNOON AND EARLY EVENING HOURS...WHERE CATEGORICAL POPS
WERE USED IN THE FORECAST GRIDS. INSERTED HEAVY RAINFALL WORDING
INTO THE ZONES FOR THESE LOCATIONS...AND WIDESPREAD RAINFALL
TOTALS TODAY AROUND 1 INCH ARE EXPECT. THE SCATTERED NATURE OF THE
HEAVY DOWNPOURS ON FRIDAY WILL PRECLUDE THE NEED FOR A FLOOD WATCH
AT THIS TIME. SLIGHT COOLING ALOFT SHOULD ALSO AID IN THE
DEVELOPMENT OF NUMEROUS MAINLY AFTERNOON AND EARLY EVENING SHOWERS
AND THUNDERSTORMS ACROSS THE REMAINDER OF INTERIOR SOUTHEAST GA.
AN EARLY START TO CONVECTION WILL LIKELY KEEP HIGHS IN THE MID TO
UPPER 80S REGION-WIDE...WITH LOCATIONS NEAR THE ALTAMAHA POSSIBLY
APPROACHING 90 BEFORE AFTERNOON CONVECTION DEVELOPS.
LOW PRESSURE IS EXPECTED TO CONSOLIDATE ALONG THE GA COAST THIS
EVENING...INCREASING SOUTHWEST STEERING FLOW IN THE LOW LEVELS.
THIS PATTERN WILL LIKELY PUSH EVENING ACTIVITY ALONG THE COAST
INTO THE OFFSHORE WATERS BY MIDNIGHT...WITH DRYING EXPECTED FROM
WEST TO EAST AS THE EVENING PROGRESSES. HI-RES MODELS INDICATE THE
POTENTIAL FOR OVERNIGHT DEVELOPMENT IN NORTH CENTRAL FL DURING THE
PRE-DAWN HOURS ON SUN. OTHERWISE...EXPECT ANOTHER ROUND OF LOW
CIGS AND SOME PATCHY FOG ACROSS INTERIOR SOUTHEAST GA. WARM AND
HUMID CONDITIONS WILL KEEP LOWS IN THE 70S.
.SHORT TERM (SUNDAY THROUGH TUESDAY)...
SUN & MON...UNSETTLED WEATHER WITH ABOVE NORMAL RAIN CHANCES WILL
CONTINUE AS HIGH MOISTURE CONTENT LINGERS OVER THE AREA (PWATS
OVER 2 INCHES) AND COMBINES WITH FORCING TRAILING A 1000-700 MB
LOW AS IT TRACKS SLOWLY NORTHWARD ALONG THE SE ATLANTIC SEABOARD.
SUN PRECIP WILL LIKELY BE ONGOING EARLY IN THE DAY ALONG A
CONVERGENT ZONE DRIFTING SOUTHWARD OVER THE AREA AS THE SURFACE
LOW TRACKS NNE ALONG THE GA/SC COAST...BUT MODELS DIVERGE WHERE
THIS ZONE WILL POSITION AROUND 12Z SUN WITH THE NMM/NAM NEAR THE
FL/GA STATE LINE AND THE ARW OVER OUR SOUTHERN FL ZONES. THE GFS
IS MUCH LESS AGGRESSIVE AND KEEPS THE HIGHER POPS OFFSHORE OF THE
LOCAL ATLANTIC COAST. FOR NOW ADVERTISED 20-30% POPS THROUGH
SUNRISE SUN...BUT AS MODEL CONSENSUS REFINES ITSELF THERE IS A
HIGH POTENTIAL FOR A BAND OF LOCALLY HEAVY RAINFALL ACROSS SOME
PORTION OF THE FORECAST AREA EARLY SUNDAY MORNING. AS THE DAY
PROGRESSES AND FORCING FROM A WEAK MID LEVEL TROUGH APPROACHES
FROM THE NW...ADDITIONAL PRECIP WILL BLOSSOM ACROSS THE FORECAST
AREA...WITH AGAIN A DIURNAL PATTERN EXPECTED WITH A FADE IN
ACTIVITY AFTER SUNSET. ADVERTISED WIDESPREAD RAINFALL CHANCES OF
60-70% WITH THE GREATEST POTENTIAL IN THE AFTN/EVENING. THE MAIN
CONVECTIVE HAZARDS WILL CONTINUE TO BE LOCALLY HEAVY RAINFALL
GIVEN SLOW STORM MOTION...EXCESSIVE LIGHTNING AND WET DOWNBURSTS
OF 40-50 MPH. MON ANOTHER ROUND OF SHOWERS/TSTORMS EXPECTED TO
FILL IN ACROSS THE AREA THROUGH THE DAY WITH A MORE EASTWARD PUSH
OF PRECIP INTO THE AFTN TOWARD THE ATLANTIC SEABOARD. HIGH TEMPS
WILL BE NEAR TO SLIGHTLY BELOW CLIMO IN THE MID/UPPER 80S...NEAR
90 SE GA...WITH LOWS MILD IN THE LOW/MID 70S POSSIBLY A FEW UPPER
60S WELL INLAND MON NIGHT AS DRIER AIR BEGINS TO FILTER IN FROM
THE WEST.
TUE...RAIN CHANCES DECREASE AS LOW PRESSURE DEPARTS TO THE NE AND
HIGH PRESSURE RIDGING BUILDS NORTHWARD FROM SOUTH FL. PWATS HOVER
NEAR 2 INCHES OVER NE FL...BUT DRIER AIR WITH PWATS FALLING NEAR
1.75 INCHES FILTERS IN OVER SE GA. STILL ENOUGH LINGERING DEEP
LAYER MOISTURE TO CONTINUE ELEVATED RAIN CHANCES N THE 40-50%
RANGE WITH LIGHT STEERING FLOW STILL SUPPORTING LOCALLY HEAVY
RAINFALL. AFTN/EVENING PRECIP WILL SHIFT FROM THE ATLANTIC COAST
MON TOWARD WEST OF HIGHWAY 301 TUE AS THE EAST COAST SEA BREEZE
BEGINS TO STRENGTHEN ITS INLAND PUSH AS THE RIDGE BUILDS IN FROM
THE SOUTH.
.LONG TERM (WEDNESDAY THROUGH SATURDAY)...
MEAN 1000-500 MB RIDGING WILL EDGE NORTHWARD AND EXTEND ACROSS
N-CENTRAL FL WHICH WILL BRING RAIN CHANCES BACK DOWN TO NEAR TO
BELOW CLIMO VALUES GIVEN INCREASED SUBSIDENCE. ADVERTISED RAIN
CHANCES IN THE 25-40% RANGE WITH THE HIGHEST VALUES OVER INLAND
AREAS BETWEEN THE ST JOHNS RIVER BASIN AND THE I-75 CORRIDOR EACH
AFTN/EVENING GIVEN WEAK STEERING FLOW. TEMPS WILL MODERATE NEAR TO
ABOVE CLIMO VALUES GIVEN STACKED RIDGING OVER THE AREA WITH HIGHS
IN THE LOW 90S/UPPER 80S INLAND TO MID 80S COAST...WITH LOWS IN
THE 70S. NEXT WEEKEND A FRONTAL ZONE BEGINS TO STALL OVER SOUTH
GA...WHICH WILL BRING AN INCREASE IN RAIN CHANCES NEXT WEEKEND.
&&
.AVIATION...
LIFR CIGS AT GNV WILL LIKELY LIFT SOON AS SHOWER ACTIVITY
APPROACHES THE TERMINAL. IFR CIGS AROUND 800 FEET ARE EXPECTED
AT SSI THROUGH AROUND 13Z...WITH VFR CIGS AROUND 5000 FT
ELSEWHERE THROUGH SUNRISE. NUMEROUS SHOWERS AND EMBEDDED
THUNDERSTORMS ARE EXPECTED TO MOVE OVER THE REGIONAL TERMINALS
AFTER 14Z...AND HAVE RECENTLY AMENED THE TAFS TO INCLUDE TEMPO
GROUPS FOR PERIODS OF IFR VISIBILITIES THROUGH AT LEAST 18Z.
PERIODS OF SUB-VFR CONDITIONS WILL REMAIN POSSIBLE AT THE REGIONAL
TERMINALS THROUGH 00Z...WITH SOUTH TO SOUTHWEST SURFACE WINDS
REMAINING NEAR OR BELOW 10 KNOTS OUTSIDE OF HEAVIER SHOWER AND
THUNDERSTORM ACTIVITY.
&&
.MARINE...
WEAK LOW PRESSURE WILL REMAIN OVER OUR REGION THIS
WEEKEND...WITH PERIODS OF NUMEROUS SHOWERS AND THUNDERSTORMS
MOVING INTO AND DEVELOPING OVER THE COASTAL WATERS THROUGH MONDAY.
OUTSIDE OF THUNDERSTORM ACTIVITY...SOUTHWEST WINDS WILL LIKELY
SURGE TO NEAR CAUTION CONDITIONS OVER THE COASTAL WATERS THIS
EVENING. A COLD FRONT WILL THEN PUSH INTO THE SOUTHEASTERN STATES
LATE IN THE WEEKEND...STALLING NEAR THE SOUTHEAST GEORGIA COAST
EARLY NEXT WEEK. SEAS WILL GENERALLY REMAIN IN THE 2 TO 4 FOOT
RANGE THROUGH MONDAY. HIGH PRESSURE WILL THEN BUILD FROM SOUTH TO
NORTH TOWARDS MIDWEEK...ALLOWING A GENERAL SOUTHERLY WIND PATTERN
WITH SPEEDS REMAINING BELOW 15 MPH.
RIP CURRENTS: LOW RISK EXPECTED THROUGH SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 89 73 90 73 / 60 60 70 60
SSI 84 75 86 74 / 80 80 60 60
JAX 87 74 89 73 / 80 80 70 60
SGJ 87 75 86 74 / 80 80 60 60
GNV 87 72 87 71 / 70 70 60 40
OCF 89 72 86 72 / 70 60 60 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
NELSON/ENYEDI
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
823 PM EDT SUN SEP 7 2014
.UPDATE...
STALLED FRONTAL BOUNDARY REMAINS ACROSS CENTRAL GA THIS EVENING. A
WAVE OF LOW PRESSURE WILL SLOWLY MOVE EAST ALONG THE BOUNDARY
OVERNIGHT. NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE FOR
THE NEXT FEW HOURS...BUT SHOULD BEGIN TO DIMINISH BY MIDNIGHT.
DON`T EXPECT SHRA/TSRA TO COMPLETELY DIMINISH SO HAVE KEPT ISO/SCT
POPS IN FOR THE ENTIRE OVERNIGHT PERIOD. IN LOCALES WHERE IT
RAINED...LOW CLOUDS AND PATCHY FOG ARE POSSIBLE TOWARDS SUNRISE.
HAVE TRIED TO ORIENT POPS ACCORDING TO RADAR TRENDS. THE 19Z RUN
OF THE HRRR PEGGED THE CONVECTION PRETTY WELL...SO ALSO FOLLOWED
SUIT. TEMPS LOOKED GOOD.
&&
.PREV DISCUSSION... /ISSUED 735 PM EDT SUN SEP 7 2014/
PREV DISCUSSION... /ISSUED 308 PM EDT SUN SEP 7 2014/
SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
MODELS IN GOOD AGREEMENT TAKING THE SURFACE LOW OVER SOUTHEAST GA
AND MOVING IT UP THE COAST. THIS WILL KEEP A NORTHEAST SURFACE FLOW
OVER THE CWA THROUGH MONDAY NIGHT. CURRENT CONVECTION OVER THE CWA
WILL DISSIPATE THIS EVENING. THERE COULD BE AN ISOLATED
SHOWER/TSTORM JUST ABOUT ANYWHERE TONIGHT AND WILL MAINTAIN A 20 POP
ACROSS MOST OF THE CWA. A LITTLE HIGHER POPS ACROSS THE EXTREME
SOUTHEAST PART OF THE CWA TONIGHT DUE TO THE PROXIMITY OF THE
SURFACE LOW. AS THE SURFACE LOW PULLS TO OUR NORTHEAST...SLIGHTLY
DRIER AIR WILL MOVE INTO NORTH GA WITH THE DEEPEST MOISTURE SHIFTING
TO PARTS OF CENTRAL GEORGIA AND THIS IS WHERE THE HIGHEST POPS WILL
BE MONDAY AFTERNOON. ANY CONVECTION THAT DOES FORM WILL DIMINISH
MONDAY NIGHT.
17
LONG TERM /TUESDAY THROUGH SUNDAY/...
A WEAKENING FRONT ACROSS SOUTH GA AND A WEAK WEDGE PERSIST ACROSS
NORTHEAST GA ON TUESDAY. FOR THE REMAINDER OF THE WEEK...UPPER
LEVEL HIGH PRESSURE RETURNS ACROSS THE SOUTHEAST U.S. AND GA
REMAINS IN A MOIST TROPICAL AIR MASS. THIS WOULD SUPPORT ISOLATED
OR SCATTERED THUNDERSTORMS EACH DAY WITH MOSTLY A DIURNAL PATTERN.
BY FRIDAY A FRONT GETS PUSHED INTO NORTH GA AS A BROAD UPPER
TROUGH DEEPENS INTO THE GREAT LAKES. THE FRONT CONTINUES TO SINK
SOUTH ON SATURDAY...HOWEVER THE ECMWF SEEMS A BIT SLOWER WITH
THIS. OVERALL...IT LOOKS LIKE THERE WILL BE SOME DRYING ACROSS THE
NORTH BY THE END OF THE PERIOD. HAVE SHOWN ONLY A SLIGHT CHANCE OF
POPS ACROSS THE NORTH FOR SATURDAY...CHANCE ELSEWHERE.
41/16
AVIATION...
00Z UPDATE...
SHOWERS AND THUNDERSTORMS HAVE BEGUN TO PUSH SW OF THE AIRPORT
TOWARDS CSG THIS EVENING. CONVECTIVE ACTIVITY COULD LINGER NEAR
CSG THROUGH 10 PM. SHOWERS MAY LINGER NEAR ATL FOR THE NEXT HOUR
OR TWO. OTHERWISE...MODELS ARE PROGGING SOME MVFR...POSSIBLY
IFR...CIGS OVERNIGHT. FOR NOW AT ATL...KEPT CIGS AROUND 010...BUT
VALUES COULD LOWER. AREAS THAT RECEIVED RAINFALL COULD ALSO HAVE
SOME MVFR FOG. ANY CIGS SHOULD TAKE UNTIL MID MORNING TO
BREAK...AND THEN AFTERNOON DIURNAL CU IS EXPECTED TO DEVELOP. THE
STALLED FRONT CURRENTLY ACROSS CENTRAL GA IS PROGGED TO MOVE SOUTH
TOMORROW SO THE BEST CHANCES OF CONVECTION SHOULD BE INTERSTATE 20
AND SOUTHWARD.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ON CIGS. HIGH CONFIDENCE REMAINING ELEMENTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 70 86 68 88 / 60 30 20 20
ATLANTA 71 85 70 87 / 50 30 20 20
BLAIRSVILLE 65 82 64 83 / 40 30 20 20
CARTERSVILLE 69 86 69 87 / 30 30 20 20
COLUMBUS 72 90 71 90 / 60 40 20 30
GAINESVILLE 70 84 68 86 / 50 30 20 20
MACON 70 90 70 91 / 60 50 30 30
ROME 69 89 68 89 / 30 30 20 20
PEACHTREE CITY 70 86 68 88 / 50 30 20 20
VIDALIA 72 89 71 89 / 60 60 40 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
804 PM EDT SUN SEP 7 2014
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL BRING NUMEROUS SHOWERS AND
THUNDERSTORMS TO THE REGION. THE FRONT WILL MOVE SOUTH OF THE AREA
MONDAY AS HIGH PRESSURE RIDGES IN FROM THE NORTH. ANOTHER COLD
FRONT WILL AFFECT THE REGION LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
NEARLY STATIONARY FRONT ACROSS CENTRAL SOUTH CAROLINA EARLY THIS
EVENING WILL BEGIN TO MOVE SLOWLY SOUTHEAST OVERNIGHT. WEAK
SURFACE LOW OVER COASTAL GEORGIA/SOUTH CAROLINA NEAR SAVANNAH
RIVER. SHOWERS AND THUNDERSTORMS HAVE BEEN FOCUSING ALONG THE
FRONT AND NEAR SURFACE LOW. PRECIPITABLE WATER AROUND 2 INCHES AND
HEAVY RAIN IS THE MAIN THREAT. FLOODING HAS BEEN OCCURRING IN
CENTRAL SOUTH CAROLINA THIS AFTERNOON AND EARLY EVENING. SURFACE
LOW EXPECTED TO LIFT TO THE NORTHEAST OVERNIGHT...SO FOCUS FOR
CONVECTION WILL SHIFT TO THE NORTHEAST OF AREA OVERNIGHT. RADAR
TRENDS SUGGEST WEAKENING TREND AT THE MOMENT AND RAINFALL
RATES...1 TO 2 INCHES PER HOUR SHOULD DIMINISH ALONG WITH
COVERAGE BY LATE EVENING AND OVERNIGHT.
HIGH PRESSURE WILL BEGIN BUILDING EAST ACROSS OHIO RIVER VALLEY
AND NEW ENGLAND...THEN BEGIN NUDGING SOUTHWARD AS A WEDGE INTO THE
CAROLINAS. PLENTY OF CLOUD COVER THROUGH THE NIGHT...WHICH SHOULD
HELP LOWS ONLY FALL TO AROUND 70 BY MORNING.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
COLD FRONT REMAINS WILL MEANDER ALONG THE COAST MONDAY AND MONDAY
NIGHT AS HIGH PRESSURE RIDGES IN ALONG THE MOUNTAINS. ON TUESDAY
THE FRONTAL REMAINS WILL PUSH OFFSHORE AS THE UPPER LEVEL TROUGH
ALSO MOVES INTO THE ATLANTIC BASIN. WITH THE FRONT ALONG THE COAST
A WEAK AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP ALONG THE OUTER
BANKS EARLY TUESDAY AND SLOWLY TRACK NORTHWARD THROUGH TUESDAY
NIGHT. THIS WILL KEEP THE AREA UNDER NORTHERLY FLOW MONDAY THROUGH
TUESDAY WITH WEDGE-LIKE CONDITIONS. AS SUCH HAVE MADE ONLY MINOR
ADJUSTMENTS TO TEMPERATURES FOR MONDAY...LOWERED TEMPERATURES
TUESDAY A DEGREE OR TWO AND LOWERED POPS. AFTERNOON HIGHS ON
MONDAY TO RANGE FROM THE UPPER 70S IN THE NORTHERN MIDLANDS TO THE
UPPER 80S IN THE SOUTHERN CSRA AND TUESDAY IN THE MIDDLE TO UPPER
80S. OVERNIGHT LOWS WILL BE IN THE MIDDLE 60S TO AROUND 70 EACH
NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
MODELS ARE SYNOPTICALLY IN GOOD AGREEMENT WITH SOME DIFFERENCES IN
TIMING AND INTENSITY FROM FRIDAY ONWARD. WEAK HIGH PRESSURE WILL
BE IN CONTROL OF THE AREA ON WEDNESDAY AS STRONG LOW PRESSURE
MOVES INTO THE WESTERN GREAT LAKES REGION. THIS WILL PUSH A COLD
FRONT SOUTHWARD WEDNESDAY NIGHT THROUGH THURSDAY NIGHT WITH THE
FRONT MOVING INTO THE FORECAST AREA ON FRIDAY. AS THE FRONT ENTERS
THE REGION CHANCES OF SHOWERS AND THUNDERSTORMS WILL AGAIN
INCREASE FOR FRIDAY AND SATURDAY. THE FRONT WILL MOVE OFFSHORE
LATE SUNDAY WITH COOLER AND DRIER AIR BEHIND THE FRONT BEGINNING
TO MOVE IN SUNDAY NIGHT. TEMPERATURES THROUGH THE LONG TERM WILL
BE NEAR NORMAL THROUGH FRIDAY NIGHT WITH BELOW NORMAL EXPECTED FOR
SATURDAY AND SUNDAY.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
SURFACE LOW PRESSURE ALONG THE SC/GA COAST WILL SHIFT NE OVERNIGHT
WHILE A FRONTAL BOUNDARY ACROSS THE FORECAST AREA SLOWLY DRIFTS
SOUTHEAST. SCATTERED SHOWERS WILL CONTINUE THROUGH THE PERIOD WITH
THE BEST CHANCE IN THE EASTERN MIDLANDS. WILL INCLUDE -RA AT OGB
THROUGH 02Z AND AMEND AT OTHER SITES AS NECESSARY. CONDITIONS
SHOULD REMAIN MAINLY VFR THROUGH 03Z...EXCEPT BRIEF MVFR IN
SHOWERS. HRRR AND LAMP GUIDANCE SHOW CEILINGS DETERIORATING TO IFR
DURING THE 03Z TO 06Z TIME FRAME. CONDITIONS IMPROVE SLIGHTLY TO MVFR
AFTER 15Z MONDAY AND VFR BY 18Z MONDAY. WINDS GENERALLY VARIABLE
THROUGH THE PERIOD...WITH A GENERAL DIRECTION OUT OF THE
NORTH/NORTHEAST.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN LATE NIGHT
AND EARLY MORNING STRATUS AND FOG. SCATTERED MAINLY AFTERNOON
SHOWERS AND THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
251 PM CDT SAT SEP 6 2014
.DISCUSSION...
313 AM CDT
THE COLD FRONT ASSOCIATED WITH THE ACTIVE WEATHER ON FRIDAY HAS
PUSHED OFF TO THE SOUTHEAST EARLY THIS MORNING. WE STILL HAVE SOME
SHOWERS FIRING IN CENTRAL ILLINOIS AND EXTENDING INTO PORTIONS OF
NORTHEAST ILLINOIS AND NORTHWEST INDIANA. IT IS THIS AREA WHERE THE
LOW TO MID LEVEL BAROCLINIC ZONE STILL LINGERS AS SOME ENERGY GLIDES
EASTWARD THROUGH THE BASE OF THE UPPER TROUGH AXIS MOVING THROUGH
WESTERN ONTARIO AND EXTENDING INTO THE PORTIONS OF THE MIDWEST.
UPPER AIR SOUNDINGS AND WATER VAPOR CONFIRM THE DRIER AIR MASS SET
TO INVADE OUR AREA THIS WEEKEND. KMPX 0Z SOUNDING DEPICTED A 1.2 IN
PRECIPITABLE WATER DROP IN THE LAST 24 HOURS...AND LOW TO MID 50S
DEWPOINTS HAVE ALREADY PUSHED INTO NORTH CENTRAL ILLINOIS. EXPECT
THAT TREND TO CONTINUE OVER THE REMAINDER OF THE AREA TODAY.
THE BAROCLINIC ZONE WILL CONTINUE TO PRESS EAST AS DRIER NORTHERLY
FLOW SETS IN...WITH RAIN SHOWERS MOVING ALONG WITH IT. THE CLOUD
SHIELD WILL EVENTUALLY PUSH EASTWARD AS A DRY SHEARED VORTICITY
AREA SLIDES ON BY AND SURFACE HIGH PRESSURE IN THE CENTRAL PLAINS
HEADS INTO IOWA WITH THE RIDGE AXIS EXTENDING TO THE SOUTHERN
GREAT LAKES. HIGHS TOP OFF IN THE LOWER TO MAYBE MID 70S WITH
INCREASING SUNSHINE THROUGH THE AFTERNOON. DEWPOINTS WILL BE SOME
15 DEGREES LOWER THAN FRIDAY...MAKING FOR A COMFORTABLE IF NOT
"COOL" DAY. EXPECT A LAKE BREEZE TO LIMIT THE WARM UP DOWNTOWN.
ON SUNDAY THE FLOW ALOFT IS FAIRLY ZONAL ACROSS MUCH OF THE COUNTRY
WITH NO NOTICEABLE VORT MAXES. MEANWHILE SURFACE HIGH PRESSURE
BUILDS OVER THE GREAT LAKES BY MIDDAY THEN OFF TO THE EASTERN
GREAT LAKES BY MONDAY MORNING. THIS WILL MAKE FOR ANOTHER
DELIGHTFUL EARLY METEOROLOGICAL AUTUMN AFTERNOON WITH PLENTIFUL
SUNSHINE...MILD AND DRY CONDITIONS. AND WINDS WILL BE ON THE
LIGHTER SIDE TOO. HIGHS WILL TOP OFF IN THE MID 70S..UP A FEW
DEGREES FROM SATURDAY.
THE NEXT REAL FORCING WILL BE EMANATING FROM A CURRENTLY
RETROGRADING CUTOFF LOW OFF THE NORTHERN CALIFORNIA COAST...WITH
ENERGY EVENTUALLY MIGRATING EASTWARD IN THE UPPER JET. AS SURFACE
HIGH PRESSURE CONTINUES EAST...RETURN FLOW DEVELOPS IN THE PLAINS
INCREASING MOISTURE TRANSPORT TO OUR WEST. MEDIUM RANGE MODELS A
SUBTLE WAVE THAT COMBINED WITH INCREASED WARM ADVECTION IN IOWA
THAT LOOKS TO INITIATE CONVECTION LATER MONDAY. AS THE WAVE TRACKS
EASTWARD...SOME DIFFERENCES EMERGE AS TO WHETHER THUNDERSTORMS
WILL MAKE IT INTO NORTHEAST ILLINOIS AS THE GFS SUGGESTS OR LARGELY
GRAZE THE AREA LIKE THE EC/NAM. RECENT HISTORY HAS SHOWN THESE
SUBTLE SYSTEMS MAKING BETTER EASTWARD PROGRESS THAN ANTICIPATED...SO
WILL CONTINUE WITH CHANCE POPS UNTIL GUIDANCE LATCHES ON TO
SOMETHING MORE DEFINITIVE.
ON TUESDAY...THE LEE TROUGHING THAT DEVELOPS AHEAD OF THIS FIRST
WAVE EVENTUALLY GETS A SHOVE EAST AS THE MEAN TROUGH IN THE WEST
GETS SOME MOVEMENT. A SHARP UPPER TROUGH WILL REMAIN WELL NORTH IN
CANADA...BUT SOME OF THE COOLER CANADIAN AIR LOOKS TO GET DISLODGED
A WILL DEVELOP A COLD FRONT ALONG THE INTERNATIONAL BORDER THAT WILL
SHIFT INTO MINNESOTA. MODELS/ENSEMBLES THEN DEVELOP A DECENT EARLY
AUTUMN SURFACE LOW THAT WILL TRACK ALONG THIS BOUNDARY SOMEWHERE
THROUGH THE GREAT LAKES REGION INTO WEDNESDAY. MODELS GENERALLY
AGREE ON THE TIMING BUT VARY CONSIDERABLY ON THE STRENGTH OF THE LOW
THAT DEVELOPS. THERE ARE HINTS THAT SOME OF THE MOISTURE FROM
HURRICANE NORBERT OFF OF BAJA CALIFORNIA MAY GET EMBEDDED IN THE
WESTERLY FLOW. EITHER WAY...THE LOW LEVEL WIND FIELD RESPONDS AND
COMBINES WITH A NICE FEED OF MOISTURE (PW`S > 2"). FORECAST
SOUNDINGS DEPICT A DEEP MOIST COLUMN SUGGESTIVE OF SHOWERS WITH
EMBEDDED THUNDERSTORMS WITH A HEAVY RAINFALL POTENTIAL. HAVE PUT
IN LIKELY POPS FOR THE TUESDAY NIGHT INTO WEDNESDAY MORNING PERIOD
TO ACCOUNT FOR DECENT MODEL AGREEMENT AT THIS TIME THOUGH A NUMBER
OF UPSTREAM DEPENDENCIES WILL INFLUENCE THE TRACK AND STRENGTH OF
THIS SYSTEM.
THE WESTERN UPPER TROUGH WILL BE LAGGING BEHIND THIS SHORTWAVE
TROUGH AND WILL SLOWLY PROGRESS THROUGH FOR THE LATTER HALF OF THE
WEEK...LEADING TO BELOW NORMAL TEMPERATURES AND SMALL CHANCES FOR
RAIN SHOWERS. SURFACE HIGH PRESSURE SHOULD BE REDEVELOPING DURING
THIS TIME AND THUS THE LOWER PRECIP POTENTIAL. KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* NONE
IZZI
//DISCUSSION...UPDATED 20Z...
SOMEWHAT ILL-DEFINED LAKE BREEZE BOUNDARY EXTENDS FROM JUST EAST
OF ORD TO JJUST WEST OF MDW. WINDS SOMEWHAT VARIABLE FROM THE
NORTH OR NORTHEAST ON EITHER SIDE OF THE BOUNDARY...SO EVEN IF IT
WERE TO WOBBLE WEST FARTHER WOULD ANTICIPATE PREVAILING WINDS TO
REMAIN LESS THAN 10KT.
IZZI
UPDATED 18Z...
ONE AND ONLY FORECAST CHALLENGE THIS AFTERNOON IS WITH WIND
DIRECTION THIS AFTERNOON INTO VERY EARLY EVENING. LAKE BREEZE HAS
BEGUN TO SHOW UP ON TERMINAL DOPPLER AND ANTICIPATE THAT IT WILL
MAKE A PUSH INLAND THIS AFTERNOON. ORIENTATION OF THE LAKE BREEZE
FAVORS A PASSAGE AND STEADY NE WIND DEVELOPING FOR A TIME AT MDW.
FAR LESS CERTAINTY REGARDING POSSIBLE LAKE BREEZE PASSAGE AT ORD
SO PLAN TO RUN WITH MORE STRAIGHT NORTHERLY IN THE TAF BUT WILL
MONITOR FOR POSSIBLE LAKE BREEZE PASSAGE LATE THIS AFTERNOON.
OTHERWISE...VFR CONDITIONS EXPECTED.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN ALL ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH MONDAY...VFR. SLGT CHANCE TSRA LATE MONDAY
NIGHT.
TUESDAY THROUGH THURSDAY...PERIODIC CHANCES OF SHRA/TSRA...
ESPECIALLY TUESDAY NIGHT INTO WEDNESDAY.
FRIDAY...VFR.
RATZER
&&
.MARINE...
247 PM CDT
HIGH PRESSURE CENTERED OVER THE SOUTHERN PLAINS WILL EXPAND EASTWARD
ACROSS THE GREAT LAKES INTO SUNDAY BEFORE IT EVOLVES FURTHER EAST
AND BECOMES CENTERED OVER THE ST. LAWRENCE RIVER VALLEY MONDAY. A
WEAK COOL FRONT CROSSING THE NORTHERN PART OF THE LAKE THIS
AFTERNOON HAS BROUGHT AN INCREASE IN WIND SPEED ACROSS THE NORTH BUT
THE HIGH SPREADING IN WILL ALLOW SPEEDS TO DIMINISH THIS EVENING AND
TURN SOUTHERLY OVERNIGHT. THE DIRECTION WILL BE MORE VARIABLE SOUTH
BUT SPEEDS WILL SLACKEN AS WELL ALLOWING WAVES TO SUBSIDE. WILL GO
AHEAD AND CARRY THAT SMALL CRAFT ADVISORY UNTIL 7 PM CDT AS
SCHEDULED. SOUTHERLY WINDS WILL GRADUALLY BECOME STEADIER SUNDAY AND
SUNDAY NIGHT...ESPECIALLY ACROSS CENTRAL AND NORTHERN SECTIONS...AS
THE HIGH SHIFTS EAST AND WEAK LOW PRESSURE MOVES INTO THE CENTRAL
AND NORTHERN PLAINS. THE GRADIENT WILL LIKELY BE WEAK ENOUGH TO
SUPPORT A SHIFT TO ONSHORE FLOW ACROSS THE SOUTHERN PART OF THE LAKE
SUNDAY AFTERNOON.
THE BIGGEST FORECAST CONCERN COMES AS AN UPPER TROUGH DIGS INTO THE
CENTRAL U.S. TUESDAY HELPING SURFACE LOW PRESSURE INTENSIFY AND MOVE
NORTHEAST FROM THE CENTRAL PLAINS TO THE WESTERN GREAT LAKES
WEDNESDAY. THIS SYSTEM WILL BEAR CLOSE WATCH AS THE UPPER FLOW
PATTERN IS EXPECTED TO BECOME QUITE AMPLIFIED SUPPORTING A RAPID
DEEPENING OF THE SYSTEM. HAVE ALREADY SEEN VARIABILITY IN HOW MEDIUM
RANGE GUIDANCE HAS HANDLED THIS SYSTEM BUT THE TREND HAS BEEN TO BE
STRONGER. STILL TOO EARLY FOR DETAILS BUT A DEEPENING LOW TRACKING
NEAR OR NORTH OF THE LAKE IS PRIME TO PRODUCE GALES SO THE FIRST
SIGNIFICANT SYSTEM OF THE SEASON MAY BE IN THE MAKING. WILL NEED TO
WATCH THIS SYSTEM CLOSELY OVER THE NEXT FEW DAYS AS AN EXTENDED
PERIOD OF LOWER END GALES AND A SHORTER PERIOD OR PERIODS OF MID OR
EVEN HIGH END GALES IS PLAUSIBLE. FOR NOW WILL MENTION POSSIBLE
GALES GIVEN THE TIME RANGE OF THE FORECAST AT THIS POINT. HIGH
PRESSURE WOULD LIKELY BUILD IN BEHIND THE SYSTEM LATE NEXT WEEK OR
EARLY NEXT WEEKEND.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 7 PM SATURDAY.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 7 PM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
101 PM CDT Sat Sep 6 2014
.UPDATE...
ISSUED AT 1051 AM CDT SAT SEP 6 2014
Persistent stratus deck behind the frontal boundary that passed
through last night very slow to clear. Concerned for the high
temps in the far SE. In the last couple hours, the clouds have
started to progress slightly to the SE and less concerned with the
highs in the NW, but still have a ways to go with temps lingering
in the 60s through mid morning. Will only make slight adjustments
in the NW...possibly a couple degrees in the SE. Some minor and
sct showers remain in the far SE and see no reason to pull the
mention, and will continue to adjust to trends. Updates out
momentarily.
&&
.SHORT TERM...(Today)
ISSUED AT 259 AM CDT SAT SEP 6 2014
Despite passage of a cold front during the evening hours,
scattered light showers persist across the southern two-thirds of
the KILX CWA early this morning. NAM/GFS/ECMWF have all verified
too far north with lingering precip field at 06z, while the latest
HRRR seems to have the best handle on the current situation.
Following the latest radar trends and HRRR solution, have
maintained low chance PoPs along/south of I-70 into the early
afternoon before showers gradually push further southward into the
Ohio River Valley. Meanwhile further north, have gone with a dry
forecast across the remainder of the CWA. Skies will start out
mostly cloudy, followed by a steady clearing trend from north to
south as the day progresses. Afternoon high temperatures will be
quite a bit cooler than yesterday, with readings remaining in the
lower to middle 70s.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 259 AM CDT SAT SEP 6 2014
High pressure will build into the region tonight into Sunday,
resulting in clear skies and cool temperatures. Light winds/dry
airmass will allow excellent radiational cooling to take place
tonight, with lows bottoming out in the lower to middle 50s. On the
flip side, full sunshine acting on the dry airmass will help
temperatures rebound nicely into the middle to upper 70s on Sunday.
Once the upper trough responsible for the cool weather lifts into
eastern Canada, an active zonal flow pattern will develop across the
CONUS next week. Two distinct systems will track through this flow,
bringing rain chances to central Illinois. The first is progged to
track from the Northern Plains Sunday night into the southern Great
Lakes by Tuesday morning. Models are developing showers/storms in
advance of this feature Monday night as low-level jet focuses across
northern Missouri/southern Iowa. Solutions vary as to how far east
into the prevailing surface ridge axis precip will penetrate late
Monday night into Tuesday. Given presence of very dry airmass
initially and only weak upper support with the short-wave, will keep
highest PoPs confined to the Illinois River Valley Monday night.
Further east, will go with a dry forecast along/east of I-57. Will
only mention low chance PoPs on Tuesday as nocturnal convection
undergoes diurnal weakening further eastward into the dry airmass.
Second stronger wave will approach Tuesday night into Wednesday,
bringing a much better chance for widespread rain. Models are
suggesting moisture from tropical system in the Pacific may get
drawn into this feature, resulting in unseasonably high precipitable
water values in excess of 2 inches. GFS/ECMWF/GEM all bring a hefty
slug of precip into Illinois late Tuesday night into Wednesday
accordingly: however, axis of heaviest precip still remains in
question. Have boosted PoPs to likely across the northern
two-thirds of the CWA Tuesday night and Wednesday. Initial QPF from
WPC indicates the potential for 1 to 2 inches of rain across much of
the area during this time, with the highest amounts across the
Illinois River Valley. Once wave passes to the east, strong cold
front will settle southward, taking the higher rain chances into the
far southern CWA Wednesday night. After that, most model guidance
is advertising a cooler/drier day on Thursday followed by a shot of
even cooler air by the end of the week. Both the GFS and ECMWF show
850mb temps dropping to around 0c by next Saturday morning,
potentially resulting in highs only in the middle to upper 60s and
lows dipping into the 40s next weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1254 PM CDT SAT SEP 6 2014
Persistent stratus remaining in place over Central IL. Slow
clearing to the NW just as quickly being filled in with diurnal CU
development. PIA should be clearing pretty soon and as long as the
trend continues, most sites will be breaking back to VFR within
the first few hours and will get updated, with the exception of
CMI and DEC which may end up under the stratus for a few more
hours. VFR into the overnight anticipated. Concern for the
persistent stratus trapping some of the deeper moisture at the sfc
through to the early morning hours. Dwpts in the SE still
lingering in the 60s and will drive threat for fog in the early
morning hours. Have dropped PIA BMI and SPI to MVFR and CMI and
DEC to IFR. May be a bit too optimistic depending on how much of
this moisture can mix out this afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1124 AM CDT SAT SEP 6 2014
.DISCUSSION...
313 AM CDT
THE COLD FRONT ASSOCIATED WITH THE ACTIVE WEATHER ON FRIDAY HAS
PUSHED OFF TO THE SOUTHEAST EARLY THIS MORNING. WE STILL HAVE SOME
SHOWERS FIRING IN CENTRAL ILLINOIS AND EXTENDING INTO PORTIONS OF
NORTHEAST ILLINOIS AND NORTHWEST INDIANA. IT IS THIS AREA WHERE THE
LOW TO MID LEVEL BAROCLINIC ZONE STILL LINGERS AS SOME ENERGY GLIDES
EASTWARD THROUGH THE BASE OF THE UPPER TROUGH AXIS MOVING THROUGH
WESTERN ONTARIO AND EXTENDING INTO THE PORTIONS OF THE MIDWEST.
UPPER AIR SOUNDINGS AND WATER VAPOR CONFIRM THE DRIER AIR MASS SET
TO INVADE OUR AREA THIS WEEKEND. KMPX 0Z SOUNDING DEPICTED A 1.2 IN
PRECIPITABLE WATER DROP IN THE LAST 24 HOURS...AND LOW TO MID 50S
DEWPOINTS HAVE ALREADY PUSHED INTO NORTH CENTRAL ILLINOIS. EXPECT
THAT TREND TO CONTINUE OVER THE REMAINDER OF THE AREA TODAY.
THE BAROCLINIC ZONE WILL CONTINUE TO PRESS EAST AS DRIER NORTHERLY
FLOW SETS IN...WITH RAIN SHOWERS MOVING ALONG WITH IT. THE CLOUD
SHIELD WILL EVENTUALLY PUSH EASTWARD AS A DRY SHEARED VORTICITY
AREA SLIDES ON BY AND SURFACE HIGH PRESSURE IN THE CENTRAL PLAINS
HEADS INTO IOWA WITH THE RIDGE AXIS EXTENDING TO THE SOUTHERN
GREAT LAKES. HIGHS TOP OFF IN THE LOWER TO MAYBE MID 70S WITH
INCREASING SUNSHINE THROUGH THE AFTERNOON. DEWPOINTS WILL BE SOME
15 DEGREES LOWER THAN FRIDAY...MAKING FOR A COMFORTABLE IF NOT
"COOL" DAY. EXPECT A LAKE BREEZE TO LIMIT THE WARM UP DOWNTOWN.
ON SUNDAY THE FLOW ALOFT IS FAIRLY ZONAL ACROSS MUCH OF THE COUNTRY
WITH NO NOTICEABLE VORT MAXES. MEANWHILE SURFACE HIGH PRESSURE
BUILDS OVER THE GREAT LAKES BY MIDDAY THEN OFF TO THE EASTERN
GREAT LAKES BY MONDAY MORNING. THIS WILL MAKE FOR ANOTHER
DELIGHTFUL EARLY METEOROLOGICAL AUTUMN AFTERNOON WITH PLENTIFUL
SUNSHINE...MILD AND DRY CONDITIONS. AND WINDS WILL BE ON THE
LIGHTER SIDE TOO. HIGHS WILL TOP OFF IN THE MID 70S..UP A FEW
DEGREES FROM SATURDAY.
THE NEXT REAL FORCING WILL BE EMANATING FROM A CURRENTLY
RETROGRADING CUTOFF LOW OFF THE NORTHERN CALIFORNIA COAST...WITH
ENERGY EVENTUALLY MIGRATING EASTWARD IN THE UPPER JET. AS SURFACE
HIGH PRESSURE CONTINUES EAST...RETURN FLOW DEVELOPS IN THE PLAINS
INCREASING MOISTURE TRANSPORT TO OUR WEST. MEDIUM RANGE MODELS A
SUBTLE WAVE THAT COMBINED WITH INCREASED WARM ADVECTION IN IOWA
THAT LOOKS TO INITIATE CONVECTION LATER MONDAY. AS THE WAVE TRACKS
EASTWARD...SOME DIFFERENCES EMERGE AS TO WHETHER THUNDERSTORMS
WILL MAKE IT INTO NORTHEAST ILLNOIS AS THE GFS SUGGESTS OR LARGELY
GRAZE THE AREA LIKE THE EC/NAM. RECENT HISTORY HAS SHOWN THESE
SUBTLE SYSTEMS MAKING BETTER EASTWARD PROGRESS THAN ANTICIPATED...SO
WILL CONTINUE WITH CHANCE POPS UNTIL GUIDANCE LATCHES ON TO
SOMETHING MORE DEFINITIVE.
ON TUESDAY...THE LEE TROUGHING THAT DEVELOPS AHEAD OF THIS FIRST
WAVE EVENTUALLY GETS A SHOVE EAST AS THE MEAN TROUGH IN THE WEST
GETS SOME MOVEMENT. A SHARP UPPER TROUGH WILL REMAIN WELL NORTH IN
CANADA...BUT SOME OF THE COOLER CANADIAN AIR LOOKS TO GET DISLODGED
A WILL DEVELOP A COLD FRONT ALONG THE INTERNATIONAL BORDER THAT WILL
SHIFT INTO MINNESOTA. MODELS/ENSEMBLES THEN DEVELOP A DECENT EARLY
AUTUMN SURFACE LOW THAT WILL TRACK ALONG THIS BOUNDARY SOMEWHERE
THROUGH THE GREAT LAKES REGION INTO WEDNESDAY. MODELS GENERALLY
AGREE ON THE TIMING BUT VARY CONSIDERABLY ON THE STRENGTH OF THE LOW
THAT DEVELOPS. THERE ARE HINTS THAT SOME OF THE MOISTURE FROM
HURRICANE NORBERT OFF OF BAJA CALIFORNIA MAY GET EMBEDDED IN THE
WESTERLY FLOW. EITHER WAY...THE LOW LEVEL WIND FIELD RESPONDS AND
COMBINES WITH A NICE FEED OF MOISTURE (PW`S > 2"). FORECAST
SOUNDINGS DEPICT A DEEP MOIST COLUMN SUGGESTIVE OF SHOWERS WITH
EMBEDDED THUNDERSTORMS WITH A HEAVY RAINFALL POTENTIAL. HAVE PUT
IN LIKELY POPS FOR THE TUESDAY NIGHT INTO WEDNESDAY MORNING PERIOD
TO ACCOUNT FOR DECENT MODEL AGREEMENT AT THIS TIME THOUGH A NUMBER
OF UPSTREAM DEPENDENCIES WILL INFLUENCE THE TRACK AND STRENGTH OF
THIS SYSTEM.
THE WESTERN UPPER TROUGH WILL BE LAGGING BEHIND THIS SHORTWAVE
TROUGH AND WILL SLOWLY PROGRESS THROUGH FOR THE LATTER HALF OF THE
WEEK...LEADING TO BELOW NORMAL TEMPERATURES AND SMALL CHANCES FOR
RAIN SHOWERS. SURFACE HIGH PRESSURE SHOULD BE REDEVELOPING DURING
THIS TIME AND THUS THE LOWER PRECIP POTENTIAL. KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* NORTHERLY TO NORTHEASTERLY WINDS TROUGH THIS AFTERNOON
IZZI
//DISCUSSION...UPDATED 12Z...
LOW LEVELS CONTINUE TO DRY OUT WITH NORTH-NORTHWEST WINDS THIS
MORNING. A FEW PATCHES OF 2500-3000 FT MVFR LINGER SOUTH OF KMDW
AND TOWARDS KGYY...THOUGH THESE SHOULD BE DISSIPATING QUICKLY THIS
MORNING WITH VFR CONDITIONS EXPECTED FOR THE REMAINDER OF THE TAF
PERIOD.
ONLY REAL CONCERN IS WITH THE POTENTIAL FOR A LAKE BREEZE WIND
SHIFT THIS AFTERNOON ACROSS MAINLY KMDW AND KGYY. HIGH-RES
GUIDANCE TRENDS CONTINUE TO INDICATE KORD TO REMAIN NORTH-
NORTHWEST IN 340-360 DEGREE RANGE WHILE WINDS SHIFT TO 010-030
DEGREES AT KMDW AND KGYY. SPEEDS AROUND/SLIGHTLY OVER 10 KT
THROUGH MIDDAY AS HIGH PRESSURE BUILDS TOWARD THE REGION...THEN
SLACKING THIS AFTERNOON AS GRADIENT WEAKENS IN THE VICINITY OF THE
SURFACE RIDGE. WILL HAVE TO WATCH LAKE BREEZE FOR IMPACT ON KORD
BUT HAVE KEPT WIND SHIFT EAST OF THERE BASED ON STRONGER GRADIENT
WINDS THIS MORNING AND CONTINUED GUIDANCE TRENDS INDICATING NO
LAKE BREEZE PASSAGE. OTHERWISE...WINDS DIMINISH QUICKLY EARLY THIS
EVENING AND ASSUME A VARIABLE/WESTERLY DIRECTION LESS THAN 5 KT.
COULD BE SOME PATCHY MVFR FOG MAINLY OUTSIDE METRO CHICAGO.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* LOW-MEDIUM CONFIDENCE IN LAKE BREEZE TIMING/INLAND EXTENT.
* HIGH CONFIDENCE ALL OTHER ELEMENTS.
RATZER/IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH MONDAY...VFR. SLGT CHANCE TSRA LATE MONDAY
NIGHT.
TUESDAY THROUGH THURSDAY...PERIODIC CHANCES OF SHRA/TSRA...
ESPECIALLY TUESDAY NIGHT INTO WEDNESDAY.
FRIDAY...VFR.
RATZER
&&
.MARINE...
259 AM CDT
HIGH PRESSURE OVER THE CENTRAL PLAINS WILL MOVE SLOWLY EAST INTO THE
MIDWEST TONIGHT AND ACROSS THE LOWER LAKES BY SUNDAY NIGHT. BRIEF
PERIOD OF GUSTY NORTH-NORTHWEST WINDS TO 25 KT THIS MORNING AS THE
SURFACE HIGH DEVELOPS TOWARD THE LAKE SHOULD RELAX THIS AFTERNOON
ESPECIALLY ON SOUTHERN LAKE MICHIGAN WHERE THE RIDGE AXIS WILL
RESIDE BY EVENING. FARTHER NORTH...A WEAK LOW WILL PASS ACROSS THE
NORTHERN LAKES TONIGHT...BACKING WINDS MORE WESTERLY WITH GUSTS
20-25 KT AGAIN AHEAD OF A WEAK COLD FRONT THIS AFTERNOON...THEN
VEERING NORTH TOWARD EVENING AND DIMINISHING. WINDS WILL COME BACK
AROUND TO THE SOUTH-SOUTHEAST SUNDAY AND SUNDAY NIGHT AS THE HIGH
DRIFTS OFF TO THE EAST ACROSS THE LOWER LAKES INTO NEW ENGLAND.
WINDS LOOK TO REMAIN FAIRLY MODEST FROM THE SOUTH EARLY IN THE WEEK
WHILE LOW PRESSURE DEVELOPS OVER THE PLAINS. THIS LOW IS EXPECTED TO
DEEPEN AND EVENTUALLY TRACK TOWARD THE WESTERN LAKES BY MID-WEEK.
THE EXACT TRACK REMAINS A LITTLE UNCERTAIN AT THIS POINT...THOUGH
MOST MODEL GUIDANCE BRINGS THE LOW ACROSS IOWA INTO WISCONSIN OR
NORTHERN ILLINOIS ON WEDNESDAY...BEFORE SOLUTIONS DIVERGE. IN EITHER
CASE...WINDS ARE EXPECTED TO BACK SOUTHEAST-EAST AND INCREASE AS THE
GRADIENT TIGHTENS UP IN ADVANCE OF THE LOW TUESDAY NIGHT INTO EARLY
WEDNESDAY.
NORTH-NORTHWEST WINDS AROUND 20 KT THIS MORNING PRODUCING 4-5
FOOTERS AT BUOYS ALONG THE SOUTH/SOUTHEAST SHORE. SMALL CRAFT
ADVISORY WILL REMAIN IN EFFECT THROUGH THIS AFTERNOON FOR THE
INDIANA NEARSHORE WATERS. WINDS DIMINISH AND BACK QUICKLY TOWARD
EVENING WHICH SHOULD ALLOW WAVES TO SUBSIDE FAIRLY QUICKLY BY
EVENING.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 7 PM SATURDAY.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 7 PM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1055 AM CDT Sat Sep 6 2014
.UPDATE...
ISSUED AT 1051 AM CDT SAT SEP 6 2014
Persistent stratus deck behind the frontal boundary that passed
through last night very slow to clear. Concerned for the high
temps in the far SE. In the last couple hours, the clouds have
started to progress slightly to the SE and less concerned with the
highs in the NW, but still have a ways to go with temps lingering
in the 60s through mid morning. Will only make slight adjustments
in the NW...possibly a couple degrees in the SE. Some minor and
sct showers remain in the far SE and see no reason to pull the
mention, and will continue to adjust to trends. Updates out
momentarily.
&&
.SHORT TERM...(Today)
ISSUED AT 259 AM CDT SAT SEP 6 2014
Despite passage of a cold front during the evening hours,
scattered light showers persist across the southern two-thirds of
the KILX CWA early this morning. NAM/GFS/ECMWF have all verified
too far north with lingering precip field at 06z, while the latest
HRRR seems to have the best handle on the current situation.
Following the latest radar trends and HRRR solution, have
maintained low chance PoPs along/south of I-70 into the early
afternoon before showers gradually push further southward into the
Ohio River Valley. Meanwhile further north, have gone with a dry
forecast across the remainder of the CWA. Skies will start out
mostly cloudy, followed by a steady clearing trend from north to
south as the day progresses. Afternoon high temperatures will be
quite a bit cooler than yesterday, with readings remaining in the
lower to middle 70s.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 259 AM CDT SAT SEP 6 2014
High pressure will build into the region tonight into Sunday,
resulting in clear skies and cool temperatures. Light winds/dry
airmass will allow excellent radiational cooling to take place
tonight, with lows bottoming out in the lower to middle 50s. On the
flip side, full sunshine acting on the dry airmass will help
temperatures rebound nicely into the middle to upper 70s on Sunday.
Once the upper trough responsible for the cool weather lifts into
eastern Canada, an active zonal flow pattern will develop across the
CONUS next week. Two distinct systems will track through this flow,
bringing rain chances to central Illinois. The first is progged to
track from the Northern Plains Sunday night into the southern Great
Lakes by Tuesday morning. Models are developing showers/storms in
advance of this feature Monday night as low-level jet focuses across
northern Missouri/southern Iowa. Solutions vary as to how far east
into the prevailing surface ridge axis precip will penetrate late
Monday night into Tuesday. Given presence of very dry airmass
initially and only weak upper support with the short-wave, will keep
highest PoPs confined to the Illinois River Valley Monday night.
Further east, will go with a dry forecast along/east of I-57. Will
only mention low chance PoPs on Tuesday as nocturnal convection
undergoes diurnal weakening further eastward into the dry airmass.
Second stronger wave will approach Tuesday night into Wednesday,
bringing a much better chance for widespread rain. Models are
suggesting moisture from tropical system in the Pacific may get
drawn into this feature, resulting in unseasonably high precipitable
water values in excess of 2 inches. GFS/ECMWF/GEM all bring a hefty
slug of precip into Illinois late Tuesday night into Wednesday
accordingly: however, axis of heaviest precip still remains in
question. Have boosted PoPs to likely across the northern
two-thirds of the CWA Tuesday night and Wednesday. Initial QPF from
WPC indicates the potential for 1 to 2 inches of rain across much of
the area during this time, with the highest amounts across the
Illinois River Valley. Once wave passes to the east, strong cold
front will settle southward, taking the higher rain chances into the
far southern CWA Wednesday night. After that, most model guidance
is advertising a cooler/drier day on Thursday followed by a shot of
even cooler air by the end of the week. Both the GFS and ECMWF show
850mb temps dropping to around 0c by next Saturday morning,
potentially resulting in highs only in the middle to upper 60s and
lows dipping into the 40s next weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 600 AM CDT SAT SEP 6 2014
Areas of MVFR and local IFR cigs will give way to VFR conditions
later this morning across the entire area as high pressure builds
in from the northwest. Band of stratus continues to edge slowly
to the southeast this morning with a large area mid level clouds
generally above 12000 feet remaining. The mid cloud band will also
slowly pull away from the area later this morning into the early
afternoon hours. Forecast soundings suggest cumulus to develop
across the forecast area by early afternoon with bases of 3000-4000
feet which should dissipate by late afternoon. Surface winds will
remain out of a northerly direction today with speeds in the 8 to
13 kt range. Tonight, as the large area of high pressure settles
in, look for nearly calm winds to prevail.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
642 AM CDT SAT SEP 6 2014
.DISCUSSION...
313 AM CDT
THE COLD FRONT ASSOCIATED WITH THE ACTIVE WEATHER ON FRIDAY HAS
PUSHED OFF TO THE SOUTHEAST EARLY THIS MORNING. WE STILL HAVE SOME
SHOWERS FIRING IN CENTRAL ILLINOIS AND EXTENDING INTO PORTIONS OF
NORTHEAST ILLINOIS AND NORTHWEST INDIANA. IT IS THIS AREA WHERE THE
LOW TO MID LEVEL BAROCLINIC ZONE STILL LINGERS AS SOME ENERGY GLIDES
EASTWARD THROUGH THE BASE OF THE UPPER TROUGH AXIS MOVING THROUGH
WESTERN ONTARIO AND EXTENDING INTO THE PORTIONS OF THE MIDWEST.
UPPER AIR SOUNDINGS AND WATER VAPOR CONFIRM THE DRIER AIR MASS SET
TO INVADE OUR AREA THIS WEEKEND. KMPX 0Z SOUNDING DEPICTED A 1.2 IN
PRECIPITABLE WATER DROP IN THE LAST 24 HOURS...AND LOW TO MID 50S
DEWPOINTS HAVE ALREADY PUSHED INTO NORTH CENTRAL ILLINOIS. EXPECT
THAT TREND TO CONTINUE OVER THE REMAINDER OF THE AREA TODAY.
THE BAROCLINIC ZONE WILL CONTINUE TO PRESS EAST AS DRIER NORTHERLY
FLOW SETS IN...WITH RAIN SHOWERS MOVING ALONG WITH IT. THE CLOUD
SHIELD WILL EVENTUALLY PUSH EASTWARD AS A DRY SHEARED VORTICITY
AREA SLIDES ON BY AND SURFACE HIGH PRESSURE IN THE CENTRAL PLAINS
HEADS INTO IOWA WITH THE RIDGE AXIS EXTENDING TO THE SOUTHERN
GREAT LAKES. HIGHS TOP OFF IN THE LOWER TO MAYBE MID 70S WITH
INCREASING SUNSHINE THROUGH THE AFTERNOON. DEWPOINTS WILL BE SOME
15 DEGREES LOWER THAN FRIDAY...MAKING FOR A COMFORTABLE IF NOT
"COOL" DAY. EXPECT A LAKE BREEZE TO LIMIT THE WARM UP DOWNTOWN.
ON SUNDAY THE FLOW ALOFT IS FAIRLY ZONAL ACROSS MUCH OF THE COUNTRY
WITH NO NOTICEABLE VORT MAXES. MEANWHILE SURFACE HIGH PRESSURE
BUILDS OVER THE GREAT LAKES BY MIDDAY THEN OFF TO THE EASTERN
GREAT LAKES BY MONDAY MORNING. THIS WILL MAKE FOR ANOTHER
DELIGHTFUL EARLY METEOROLOGICAL AUTUMN AFTERNOON WITH PLENTIFUL
SUNSHINE...MILD AND DRY CONDITIONS. AND WINDS WILL BE ON THE
LIGHTER SIDE TOO. HIGHS WILL TOP OFF IN THE MID 70S..UP A FEW
DEGREES FROM SATURDAY.
THE NEXT REAL FORCING WILL BE EMANATING FROM A CURRENTLY
RETROGRADING CUTOFF LOW OFF THE NORTHERN CALIFORNIA COAST...WITH
ENERGY EVENTUALLY MIGRATING EASTWARD IN THE UPPER JET. AS SURFACE
HIGH PRESSURE CONTINUES EAST...RETURN FLOW DEVELOPS IN THE PLAINS
INCREASING MOISTURE TRANSPORT TO OUR WEST. MEDIUM RANGE MODELS A
SUBTLE WAVE THAT COMBINED WITH INCREASED WARM ADVECTION IN IOWA
THAT LOOKS TO INITIATE CONVECTION LATER MONDAY. AS THE WAVE TRACKS
EASTWARD...SOME DIFFERENCES EMERGE AS TO WHETHER THUNDERSTORMS
WILL MAKE IT INTO NORTHEAST ILLNOIS AS THE GFS SUGGESTS OR LARGELY
GRAZE THE AREA LIKE THE EC/NAM. RECENT HISTORY HAS SHOWN THESE
SUBTLE SYSTEMS MAKING BETTER EASTWARD PROGRESS THAN ANTICIPATED...SO
WILL CONTINUE WITH CHANCE POPS UNTIL GUIDANCE LATCHES ON TO
SOMETHING MORE DEFINITIVE.
ON TUESDAY...THE LEE TROUGHING THAT DEVELOPS AHEAD OF THIS FIRST
WAVE EVENTUALLY GETS A SHOVE EAST AS THE MEAN TROUGH IN THE WEST
GETS SOME MOVEMENT. A SHARP UPPER TROUGH WILL REMAIN WELL NORTH IN
CANADA...BUT SOME OF THE COOLER CANADIAN AIR LOOKS TO GET DISLODGED
A WILL DEVELOP A COLD FRONT ALONG THE INTERNATIONAL BORDER THAT WILL
SHIFT INTO MINNESOTA. MODELS/ENSEMBLES THEN DEVELOP A DECENT EARLY
AUTUMN SURFACE LOW THAT WILL TRACK ALONG THIS BOUNDARY SOMEWHERE
THROUGH THE GREAT LAKES REGION INTO WEDNESDAY. MODELS GENERALLY
AGREE ON THE TIMING BUT VARY CONSIDERABLY ON THE STRENGTH OF THE LOW
THAT DEVELOPS. THERE ARE HINTS THAT SOME OF THE MOISTURE FROM
HURRICANE NORBERT OFF OF BAJA CALIFORNIA MAY GET EMBEDDED IN THE
WESTERLY FLOW. EITHER WAY...THE LOW LEVEL WIND FIELD RESPONDS AND
COMBINES WITH A NICE FEED OF MOISTURE (PW`S > 2"). FORECAST
SOUNDINGS DEPICT A DEEP MOIST COLUMN SUGGESTIVE OF SHOWERS WITH
EMBEDDED THUNDERSTORMS WITH A HEAVY RAINFALL POTENTIAL. HAVE PUT
IN LIKELY POPS FOR THE TUESDAY NIGHT INTO WEDNESDAY MORNING PERIOD
TO ACCOUNT FOR DECENT MODEL AGREEMENT AT THIS TIME THOUGH A NUMBER
OF UPSTREAM DEPENDENCIES WILL INFLUENCE THE TRACK AND STRENGTH OF
THIS SYSTEM.
THE WESTERN UPPER TROUGH WILL BE LAGGING BEHIND THIS SHORTWAVE
TROUGH AND WILL SLOWLY PROGRESS THROUGH FOR THE LATTER HALF OF THE
WEEK...LEADING TO BELOW NORMAL TEMPERATURES AND SMALL CHANCES FOR
RAIN SHOWERS. SURFACE HIGH PRESSURE SHOULD BE REDEVELOPING DURING
THIS TIME AND THUS THE LOWER PRECIP POTENTIAL. KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* NORTH-NORTHWEST WINDS AROUND 10 KT...LIKELY SHIFTING NORTHEAST
AT MDW THIS AFTERNOON WITH LAKE BREEZE. LESS LIKELY TO SHIFT AT
ORD.
RATZER
//DISCUSSION...UPDATED 12Z...
LOW LEVELS CONTINUE TO DRY OUT WITH NORTH-NORTHWEST WINDS THIS
MORNING. A FEW PATCHES OF 2500-3000 FT MVFR LINGER SOUTH OF KMDW
AND TOWARDS KGYY...THOUGH THESE SHOULD BE DISSIPATING QUICKLY THIS
MORNING WITH VFR CONDITIONS EXPECTED FOR THE REMAINDER OF THE TAF
PERIOD.
ONLY REAL CONCERN IS WITH THE POTENTIAL FOR A LAKE BREEZE WIND
SHIFT THIS AFTERNOON ACROSS MAINLY KMDW AND KGYY. HIGH-RES
GUIDANCE TRENDS CONTINUE TO INDICATE KORD TO REMAIN NORTH-
NORTHWEST IN 340-360 DEGREE RANGE WHILE WINDS SHIFT TO 010-030
DEGREES AT KMDW AND KGYY. SPEEDS AROUND/SLIGHTLY OVER 10 KT
THROUGH MIDDAY AS HIGH PRESSURE BUILDS TOWARD THE REGION...THEN
SLACKING THIS AFTERNOON AS GRADIENT WEAKENS IN THE VICINITY OF THE
SURFACE RIDGE. WILL HAVE TO WATCH LAKE BREEZE FOR IMPACT ON KORD
BUT HAVE KEPT WIND SHIFT EAST OF THERE BASED ON STRONGER GRADIENT
WINDS THIS MORNING AND CONTINUED GUIDANCE TRENDS INDICATING NO
LAKE BREEZE PASSAGE. OTHERWISE...WINDS DIMINISH QUICKLY EARLY THIS
EVENING AND ASSUME A VARIABLE/WESTERLY DIRECTION LESS THAN 5 KT.
COULD BE SOME PATCHY MVFR FOG MAINLY OUTSIDE METRO CHICAGO.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN LAKE BREEZE TIMING/INLAND EXTENT.
* HIGH CONFIDENCE ALL OTHER ELEMENTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH MONDAY...VFR. SLGT CHANCE TSRA LATE MONDAY
NIGHT.
TUESDAY THROUGH THURSDAY...PERIODIC CHANCES OF SHRA/TSRA...
ESPECIALLY TUESDAY NIGHT INTO WEDNESDAY.
FRIDAY...VFR.
RATZER
&&
.MARINE...
259 AM CDT
HIGH PRESSURE OVER THE CENTRAL PLAINS WILL MOVE SLOWLY EAST INTO THE
MIDWEST TONIGHT AND ACROSS THE LOWER LAKES BY SUNDAY NIGHT. BRIEF
PERIOD OF GUSTY NORTH-NORTHWEST WINDS TO 25 KT THIS MORNING AS THE
SURFACE HIGH DEVELOPS TOWARD THE LAKE SHOULD RELAX THIS AFTERNOON
ESPECIALLY ON SOUTHERN LAKE MICHIGAN WHERE THE RIDGE AXIS WILL
RESIDE BY EVENING. FARTHER NORTH...A WEAK LOW WILL PASS ACROSS THE
NORTHERN LAKES TONIGHT...BACKING WINDS MORE WESTERLY WITH GUSTS
20-25 KT AGAIN AHEAD OF A WEAK COLD FRONT THIS AFTERNOON...THEN
VEERING NORTH TOWARD EVENING AND DIMINISHING. WINDS WILL COME BACK
AROUND TO THE SOUTH-SOUTHEAST SUNDAY AND SUNDAY NIGHT AS THE HIGH
DRIFTS OFF TO THE EAST ACROSS THE LOWER LAKES INTO NEW ENGLAND.
WINDS LOOK TO REMAIN FAIRLY MODEST FROM THE SOUTH EARLY IN THE WEEK
WHILE LOW PRESSURE DEVELOPS OVER THE PLAINS. THIS LOW IS EXPECTED TO
DEEPEN AND EVENTUALLY TRACK TOWARD THE WESTERN LAKES BY MID-WEEK.
THE EXACT TRACK REMAINS A LITTLE UNCERTAIN AT THIS POINT...THOUGH
MOST MODEL GUIDANCE BRINGS THE LOW ACROSS IOWA INTO WISCONSIN OR
NORTHERN ILLINOIS ON WEDNESDAY...BEFORE SOLUTIONS DIVERGE. IN EITHER
CASE...WINDS ARE EXPECTED TO BACK SOUTHEAST-EAST AND INCREASE AS THE
GRADIENT TIGHTENS UP IN ADVANCE OF THE LOW TUESDAY NIGHT INTO EARLY
WEDNESDAY.
NORTH-NORTHWEST WINDS AROUND 20 KT THIS MORNING PRODUCING 4-5
FOOTERS AT BUOYS ALONG THE SOUTH/SOUTHEAST SHORE. SMALL CRAFT
ADVISORY WILL REMAIN IN EFFECT THROUGH THIS AFTERNOON FOR THE
INDIANA NEARSHORE WATERS. WINDS DIMINISH AND BACK QUICKLY TOWARD
EVENING WHICH SHOULD ALLOW WAVES TO SUBSIDE FAIRLY QUICKLY BY
EVENING.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 7 PM SATURDAY.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 7 PM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
615 AM CDT Sat Sep 6 2014
.SHORT TERM...(Today)
ISSUED AT 259 AM CDT SAT SEP 6 2014
Despite passage of a cold front during the evening hours,
scattered light showers persist across the southern two-thirds of
the KILX CWA early this morning. NAM/GFS/ECMWF have all verified
too far north with lingering precip field at 06z, while the latest
HRRR seems to have the best handle on the current situation.
Following the latest radar trends and HRRR solution, have
maintained low chance PoPs along/south of I-70 into the early
afternoon before showers gradually push further southward into the
Ohio River Valley. Meanwhile further north, have gone with a dry
forecast across the remainder of the CWA. Skies will start out
mostly cloudy, followed by a steady clearing trend from north to
south as the day progresses. Afternoon high temperatures will be
quite a bit cooler than yesterday, with readings remaining in the
lower to middle 70s.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 259 AM CDT SAT SEP 6 2014
High pressure will build into the region tonight into Sunday,
resulting in clear skies and cool temperatures. Light winds/dry
airmass will allow excellent radiational cooling to take place
tonight, with lows bottoming out in the lower to middle 50s. On the
flip side, full sunshine acting on the dry airmass will help
temperatures rebound nicely into the middle to upper 70s on Sunday.
Once the upper trough responsible for the cool weather lifts into
eastern Canada, an active zonal flow pattern will develop across the
CONUS next week. Two distinct systems will track through this flow,
bringing rain chances to central Illinois. The first is progged to
track from the Northern Plains Sunday night into the southern Great
Lakes by Tuesday morning. Models are developing showers/storms in
advance of this feature Monday night as low-level jet focuses across
northern Missouri/southern Iowa. Solutions vary as to how far east
into the prevailing surface ridge axis precip will penetrate late
Monday night into Tuesday. Given presence of very dry airmass
initially and only weak upper support with the short-wave, will keep
highest PoPs confined to the Illinois River Valley Monday night.
Further east, will go with a dry forecast along/east of I-57. Will
only mention low chance PoPs on Tuesday as nocturnal convection
undergoes diurnal weakening further eastward into the dry airmass.
Second stronger wave will approach Tuesday night into Wednesday,
bringing a much better chance for widespread rain. Models are
suggesting moisture from tropical system in the Pacific may get
drawn into this feature, resulting in unseasonably high precipitable
water values in excess of 2 inches. GFS/ECMWF/GEM all bring a hefty
slug of precip into Illinois late Tuesday night into Wednesday
accordingly: however, axis of heaviest precip still remains in
question. Have boosted PoPs to likely across the northern
two-thirds of the CWA Tuesday night and Wednesday. Initial QPF from
WPC indicates the potential for 1 to 2 inches of rain across much of
the area during this time, with the highest amounts across the
Illinois River Valley. Once wave passes to the east, strong cold
front will settle southward, taking the higher rain chances into the
far southern CWA Wednesday night. After that, most model guidance
is advertising a cooler/drier day on Thursday followed by a shot of
even cooler air by the end of the week. Both the GFS and ECMWF show
850mb temps dropping to around 0c by next Saturday morning,
potentially resulting in highs only in the middle to upper 60s and
lows dipping into the 40s next weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 600 AM CDT SAT SEP 6 2014
Areas of MVFR and local IFR cigs will give way to VFR conditions
later this morning across the entire area as high pressure builds
in from the northwest. Band of stratus continues to edge slowly
to the southeast this morning with a large area mid level clouds
generally above 12000 feet remaining. The mid cloud band will also
slowly pull away from the area later this morning into the early
afternoon hours. Forecast soundings suggest cumulus to develop
across the forecast area by early afternoon with bases of 3000-4000
feet which should dissipate by late afternoon. Surface winds will
remain out of a northerly direction today with speeds in the 8 to
13 kt range. Tonight, as the large area of high pressure settles
in, look for nearly calm winds to prevail.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
300 AM CDT SAT SEP 6 2014
.DISCUSSION...
836 PM CDT
CONVECTION HAS PUSHED SOUTHEAST OF THE AREA...WITH JUST A FEW
LINGERING SHOWERS SLIDING EAST ACROSS NORTHERN IL THIS EVENING.
BROAD SFC RIDGE WILL CONTINUE TO SLIDE EAST OVERNIGHT...WHICH WILL
HELP PROVIDE A STEADY DRYING TREND OVERNIGHT. SOME LINGERING
SHOWERS OVERNIGHT MAY SKIRT OUR FAR SOUTHEAST CWFA. TEMPS WILL
CONTINUE TO COOL INTO THE MID/UPR 50S GENERALLY NORTH OF
I-80...AND SOUTH OF THIS TEMPS SHUD COOL TO ARND 60.
BEACHLER
//PREV DISCUSSION...
1142 AM CDT
COLD FRONT IS MOVING THROUGH NORTHWESTERN PORTIONS OF THE CWA LATE
THIS MORNING AND SHOULD CONTINUE TO MAKE STEADY PROGRESS SOUTHEAST
ACROSS THE AREA THIS AFTERNOON. DEVELOPING PRESSURE FALLS OVER
IOWA IN ADVANCE OF SHORTWAVE TROUGH OVER NE KS/SE NE WILL PROBABLY
RESULT IN FRONT SLOWING DOWN A BIT THIS AFTERNOON. GOES EAST IS IN
RAPID SCAN MODE THIS AFTERNOON AND IS NICELY SHOWING SOME
ENHANCEMENT TO THE CUMULUS FIELD RIGHT ALONG THE IMMEDIATE FRONTAL
BOUNDARY. IN GENERAL THE CUMULUS FIELD ON SATELLITE AND OUT THE
WINDOW LOOKS VERY MUSHY AND LACKING VERTICAL GROWTH...LIKELY DUE
IN LARGE PART TO THE VERY FORMIDABLE CAP EVIDENT ON DVN/ILX MORNING
SOUNDINGS AND STILL PRESENT IN RECENT ACARS SOUNDINGS OUT OF ORD
AND MDW. CONTINUED HEATING AND DESTABILIZATION OF THE BOUNDARY
LAYER ALONG WITH FORCED ASCENT ALONG THE FRONT SHOULD EVENTUALLY
CAUSE CAP TO BUST...BUT LIKELY NOT UNTIL THE FRONT IS AT LEAST TO
A CHICAGO TO PERU LINE IF NOT FARTHER SOUTHEAST. WILL BE REWORKING
POP GRIDS TO BETTER REFLECT THIS LINE OF THINKING...INCLUDING VERY
LITTLE THREAT OF PRECIP OVER NORTHWEST CWA AND STEADILY DECREASING
CHANCE FROM THE NORTHWEST SPREADING ACROSS THE AREA THIS
AFTERNOON. POST FRONT RAIN STILL A DISTINCT POSSIBILITY THIS
EVENING INTO TONIGHT AS AFOREMENTIONED KS/NE SHORTWAVE TRACKS
NORTHEAST INTO THE REGION.
IZZI
.MEDIUM AND LONG TERM DISCUSSION...
305 PM CDT...
FOR THE REMAINDER OF THE SHORT TERM...SATURDAY AND SUNDAY...THE
SURFACE COLD FRONT SHOULD PUSH SOUTHEAST OF THE CWA THROUGH THE OHIO
VALLEY. HOWEVER...GIVEN THAT THE BULK OF THE PCPN SHOULD BE ALONG
AND BEHIND THE BOUNDARY...THERE WILL LIKELY BE SOME LINGERING
SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM OVER THE FAR
SOUTHEASTERN PORTION OF THE CWA...MAINLY AROUND BENTON COUNTY...
INDIANA. THROUGH THE DAY ON SATURDAY...HIGH PRESSURE WILL SPREAD
FROM THE CENTRAL PLAINS...ACROSS THE MIDDLE MISSISSIPPI VALLEY AND
INTO THE MIDWEST. FOLLOWING THE FROPA AND AS THE HIGH SPREADS
ACROSS THE REGION...MOISTURE WILL DIMINISH MARKEDLY...WITH DEWPOINTS
DROPPING THROUGH THE 50S ON SATURDAY AND EVEN INTO THE UPPER 40S BY
SUNDAY. TEMPERATURES ON SATURDAY WILL BE AT LEAST 10 DEGREES LOWER
THAN ON FRIDAY...ONLY IN THE LOWER 70S. UNDER FULL SUNSHINE AND
WITH LOW DEWPOINTS...TEMPERATURES ON SUNDAY SHOULD BE ABLE TO
REBOUND BACK INTO THE MIDDLE TO UPPER 70S. SO AFTER A LITTLE PCPN
OVER THE FAR SERN PORTION OF THE CWA SATURDAY MORNING...THE
REMAINDER OF THE WEEKEND SHOULD BE QUITE PLEASANT.
FOR THE LONGER TERM...FROM MONDAY THROUGH FRIDAY...EXPECT MONDAY TO
START OUT COOL AND DRY WITH LOWS IN THE LOWER 50S. HOWEVER...
ANOTHER SYSTEM IS EXPECTED TO TAKE SHAPE OVER THE CENTRAL PLAINS.
AS THE HIGH SHIFTS OFF TO THE EAST AND LOW PRESSURE DEVELOPS OVER
THE PLAINS...A RETURN FLOW OF MOISTURE WILL SET UP. THROUGH THE
DAY...INCREASING WARM/MOIST ADVECTION WILL INCREASE AS A WARM FRONT
ALSO LIFTS NORTH TROUGH THE REGION. EXPECT THAT THE NEXT ROUND OF
PCPN SHOULD SPREAD INTO THE WRN PORTIONS OF THE CWA BY MONDAY
EVENING AND CONTINUE TO SPREAD EAST ACROSS THE REMAINDER OF THE CWA
THROUGH MONDAY NIGHT AND INTO TUESDAY MORNING. THE FORECAST PICTURE
BECOMES A BIT MORE MUDDLED INTO MID WEEK AS THE LARGER SCALE MODELS
BEGIN TO DIVERGE IN THEIR SOLUTIONS...WHICH WILL HAVE A BIG IMPACT
ON THE SENSIBLE WEATHER FORECAST. THE ECMWF WANTS TO DEVELOP A
DEEPER LOW IN ASSOCIATION WITH A NRN STREAM SHORT WAVE WHILE THE GFS
IS QUICKER AND WEAKER. SINCE THE UPPER LEVEL PATTERN IS EXPECTED TO
REMAIN VERY CLOSE TO ZONAL...WITH AN UPPER RIDGE ACROSS THE SRN
CONUS ANS AND VERY BROAD TROUGHING OVER THE NRN CONUS...AND THE
FASTER WLYS ACROSS THE NRN PLAINS/GREAT LAKES REGION...HAVE TRENDED
CLOSER TO THE FASTER GFS SOLUTION AS THE ZONAL FLOW PATTERN ALOFT
WOULD FAVOR A FASTER SOLUTION. HOWEVER...THE CAVEAT HERE IS THAT IN
FAST...ZONAL FLOW...FORECAST ERRORS CAN MAGNIFY QUICKLY...
PARTICULARLY IN THE TIMING OF THE SYSTEM...SO...EVEN THOUGH A FASTER
SOLUTION WOULD MAKE SENSE...THE TIMING UNCERTAINTIES ASSOCIATED WITH
FAST ZONAL FLOW ALOFT INTRODUCES LOWER CONFIDENCE IN THE END
PRODUCTS. BY FRIDAY...AT THE END OF THE FORECAST PERIOD...THE
LONGER RANGE MODELS WANT TO CARVE OUT A SHARPER TROUGH ALOFT AND
BRING MUCH COOLER AIR INTO THE REGION. THE GFS IS ADVERTISING HIGH
TEMPS ON FRIDAY ONLY IN THE LOWER TO MIDDLE 50S. THE OLD 00Z RUN OF
THE ECMWF HAD ALSO BEEN INDICATING HIGHS ON FRIDAY ONLY IN THE LOWER
TO MIDDLE 50S...BUT THE NEW 12Z HAS BACKED OFF ON THIS A BIT AND IS
NOW INDICATING HIGHS IN THE UPPER 50S TO LOWER 60S. AT THAT TIME
RANGE...THE MOS BASED PRODUCTS ARE LIKELY TRENDING TOO CLOSE TO
CLIMATOLOGY...WITH HIGHS IN THE MIDDLE TO UPPER 60S. SO...HAVE
TRENDED THE FORECAST MAX TEMPS FOR NEXT FRIDAY IN THE LOWER
60S...BUT IT WILL BE INTERESTING TO SEE HOW THIS PLAYS OUT AND IF
THE REGIONS SEES THE FIRST SHOT OF AUTUMNAL WEATHER.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* PATCHY MVFR CIGS IN 2500-3000 FT RANGE PRIOR TO SUNRISE.
* NORTHWEST WINDS LESS THAN 10 KT BECOMING NORTHEAST LATE THIS
AFTERNOON WITH LAKE BREEZE.
RATZER
//DISCUSSION...UPDATED 06Z...
COLD FRONT HAS PUSHED WELL SOUTHEAST OF TERMINALS AS OF MIDNIGHT
WITH SHOWERS HAVING ALSO GENERALLY ALONG/SOUTHEAST OF A KSPI-KIKK-
KSBN LINE AT 06Z. LOWER VFR CIGS IN THE 3500-6000 FT RANGE LINGER
ACROSS CHICAGO AREA...WITH SOME PATCHY SCT/BKN MVFR IN THE
2000-3000 FT RANGE ALSO NOTED ACROSS THE CITY (KORD-KMDW-KGYY).
FORECAST SOUNDINGS CONTINUE TO INDICATE SLOW BUT STEADY DRY
ADVECTION ON LIGHT NORTHWEST WINDS...WITH DRYING RESULTING IN
EROSION OF MVFR LEVEL CLOUDS PRIOR TO SUNRISE. CONTINUED DRYING OF
THE COLUMN AFTER SUNRISE IS EXPECTED TO YIELD VFR CONDITIONS
THROUGH REMAINDER OF FORECAST.
HIGH PRESSURE RIDGE AXIS BUILDS SOUTHEAST FROM WISCONSIN THIS
AFTERNOON WITH WEAKER GRADIENT EXPECTED TO SUPPORT A SHIFT FROM
LIGHT NORTH-NORTHWEST OR NORTH WINDS TO NORTHEAST WINDS AS A LAKE
BREEZE DEVELOPS LATE THIS AFTERNOON OR BY EVENING. HIGH-RES MODEL
WINDS DEPICT THIS MORE FULLY FOR KGYY AND KMDW...WITH A LITTLE
LESS CONFIDENCE OF INLAND PUSH AT KORD...THOUGH A WEAKENING NORTH
GRADIENT TYPICALLY SUPPORTS SUCH A LAKE BREEZE PUSH. IN ANY CASE
PREVAILING WINDS SHOULD BE UNDER 10 KT...DECREASING TO LESS THAN 5
KT AND BECOMING WEST-SOUTHWEST AFTER SUNSET.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN TIMING SHIFT TO NORTHEAST WINDS WITH LAKE
BREEZE.
* HIGH CONFIDENCE ALL OTHER FORECAST ELEMENTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY THROUGH MONDAY...VFR.
TUESDAY THROUGH THURSDAY...PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS.
BMD
&&
.MARINE...
259 AM CDT
HIGH PRESSURE OVER THE CENTRAL PLAINS WILL MOVE SLOWLY EAST INTO THE
MIDWEST TONIGHT AND ACROSS THE LOWER LAKES BY SUNDAY NIGHT. BRIEF
PERIOD OF GUSTY NORTH-NORTHWEST WINDS TO 25 KT THIS MORNING AS THE
SURFACE HIGH DEVELOPS TOWARD THE LAKE SHOULD RELAX THIS AFTERNOON
ESPECIALLY ON SOUTHERN LAKE MICHIGAN WHERE THE RIDGE AXIS WILL
RESIDE BY EVENING. FARTHER NORTH...A WEAK LOW WILL PASS ACROSS THE
NORTHERN LAKES TONIGHT...BACKING WINDS MORE WESTERLY WITH GUSTS
20-25 KT AGAIN AHEAD OF A WEAK COLD FRONT THIS AFTERNOON...THEN
VEERING NORTH TOWARD EVENING AND DIMINISHING. WINDS WILL COME BACK
AROUND TO THE SOUTH-SOUTHEAST SUNDAY AND SUNDAY NIGHT AS THE HIGH
DRIFTS OFF TO THE EAST ACROSS THE LOWER LAKES INTO NEW ENGLAND.
WINDS LOOK TO REMAIN FAIRLY MODEST FROM THE SOUTH EARLY IN THE WEEK
WHILE LOW PRESSURE DEVELOPS OVER THE PLAINS. THIS LOW IS EXPECTED TO
DEEPEN AND EVENTUALLY TRACK TOWARD THE WESTERN LAKES BY MID-WEEK.
THE EXACT TRACK REMAINS A LITTLE UNCERTAIN AT THIS POINT...THOUGH
MOST MODEL GUIDANCE BRINGS THE LOW ACROSS IOWA INTO WISCONSIN OR
NORTHERN ILLINOIS ON WEDNESDAY...BEFORE SOLUTIONS DIVERGE. IN EITHER
CASE...WINDS ARE EXPECTED TO BACK SOUTHEAST-EAST AND INCREASE AS THE
GRADIENT TIGHTENS UP IN ADVANCE OF THE LOW TUESDAY NIGHT INTO EARLY
WEDNESDAY.
NORTH-NORTHWEST WINDS AROUND 20 KT THIS MORNING PRODUCING 4-5
FOOTERS AT BUOYS ALONG THE SOUTH/SOUTHEAST SHORE. SMALL CRAFT
ADVISORY WILL REMAIN IN EFFECT THROUGH THIS AFTERNOON FOR THE
INDIANA NEARSHORE WATERS. WINDS DIMINISH AND BACK QUICKLY TOWARD
EVENING WHICH SHOULD ALLOW WAVES TO SUBSIDE FAIRLY QUICKLY BY
EVENING.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 7 PM SATURDAY.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 7 PM SATURDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
259 AM CDT Sat Sep 6 2014
.SHORT TERM...(Today)
ISSUED AT 259 AM CDT SAT SEP 6 2014
Despite passage of a cold front during the evening hours,
scattered light showers persist across the southern two-thirds of
the KILX CWA early this morning. NAM/GFS/ECMWF have all verified
too far north with lingering precip field at 06z, while the latest
HRRR seems to have the best handle on the current situation.
Following the latest radar trends and HRRR solution, have
maintained low chance PoPs along/south of I-70 into the early
afternoon before showers gradually push further southward into the
Ohio River Valley. Meanwhile further north, have gone with a dry
forecast across the remainder of the CWA. Skies will start out
mostly cloudy, followed by a steady clearing trend from north to
south as the day progresses. Afternoon high temperatures will be
quite a bit cooler than yesterday, with readings remaining in the
lower to middle 70s.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 259 AM CDT SAT SEP 6 2014
High pressure will build into the region tonight into Sunday,
resulting in clear skies and cool temperatures. Light winds/dry
airmass will allow excellent radiational cooling to take place
tonight, with lows bottoming out in the lower to middle 50s. On the
flip side, full sunshine acting on the dry airmass will help
temperatures rebound nicely into the middle to upper 70s on Sunday.
Once the upper trough responsible for the cool weather lifts into
eastern Canada, an active zonal flow pattern will develop across the
CONUS next week. Two distinct systems will track through this flow,
bringing rain chances to central Illinois. The first is progged to
track from the Northern Plains Sunday night into the southern Great
Lakes by Tuesday morning. Models are developing showers/storms in
advance of this feature Monday night as low-level jet focuses across
northern Missouri/southern Iowa. Solutions vary as to how far east
into the prevailing surface ridge axis precip will penetrate late
Monday night into Tuesday. Given presence of very dry airmass
initially and only weak upper support with the short-wave, will keep
highest PoPs confined to the Illinois River Valley Monday night.
Further east, will go with a dry forecast along/east of I-57. Will
only mention low chance PoPs on Tuesday as nocturnal convection
undergoes diurnal weakening further eastward into the dry airmass.
Second stronger wave will approach Tuesday night into Wednesday,
bringing a much better chance for widespread rain. Models are
suggesting moisture from tropical system in the Pacific may get
drawn into this feature, resulting in unseasonably high precipitable
water values in excess of 2 inches. GFS/ECMWF/GEM all bring a hefty
slug of precip into Illinois late Tuesday night into Wednesday
accordingly: however, axis of heaviest precip still remains in
question. Have boosted PoPs to likely across the northern
two-thirds of the CWA Tuesday night and Wednesday. Initial QPF from
WPC indicates the potential for 1 to 2 inches of rain across much of
the area during this time, with the highest amounts across the
Illinois River Valley. Once wave passes to the east, strong cold
front will settle southward, taking the higher rain chances into the
far southern CWA Wednesday night. After that, most model guidance
is advertising a cooler/drier day on Thursday followed by a shot of
even cooler air by the end of the week. Both the GFS and ECMWF show
850mb temps dropping to around 0c by next Saturday morning,
potentially resulting in highs only in the middle to upper 60s and
lows dipping into the 40s next weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1157 PM CDT FRI SEP 5 2014
All sites should be VFR next 24hrs, except for during the 2hr
TEMPO group as the front and pcpn comes through the sites. The
front should come through PIA around 21z, SPI and BMI around 22Z,
DEC around 23z, and CMI around 00z. Will start with VCTS and then
have a the TEMPO group for 2hrs following. Once the front comes
through, models have a wave coming through that keeps showers
around the area during the evening hours. During the TEMPO period,
vis with the thunderstorms could drop to around 3sm. Cigs should
probably stay above 3kft. Winds will be south to southwest through
most of the period, but when the front comes through, winds will
switch to west-northwest and then northerly during the evening
hours.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...BARKER
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1237 AM CDT SAT SEP 6 2014
.DISCUSSION...
836 PM CDT
CONVECTION HAS PUSHED SOUTHEAST OF THE AREA...WITH JUST A FEW
LINGERING SHOWERS SLIDING EAST ACROSS NORTHERN IL THIS EVENING.
BROAD SFC RIDGE WILL CONTINUE TO SLIDE EAST OVERNIGHT...WHICH WILL
HELP PROVIDE A STEADY DRYING TREND OVERNIGHT. SOME LINGERING
SHOWERS OVERNIGHT MAY SKIRT OUR FAR SOUTHEAST CWFA. TEMPS WILL
CONTINUE TO COOL INTO THE MID/UPR 50S GENERALLY NORTH OF
I-80...AND SOUTH OF THIS TEMPS SHUD COOL TO ARND 60.
BEACHLER
//PREV DISCUSSION...
1142 AM CDT
COLD FRONT IS MOVING THROUGH NORTHWESTERN PORTIONS OF THE CWA LATE
THIS MORNING AND SHOULD CONTINUE TO MAKE STEADY PROGRESS SOUTHEAST
ACROSS THE AREA THIS AFTERNOON. DEVELOPING PRESSURE FALLS OVER
IOWA IN ADVANCE OF SHORTWAVE TROUGH OVER NE KS/SE NE WILL PROBABLY
RESULT IN FRONT SLOWING DOWN A BIT THIS AFTERNOON. GOES EAST IS IN
RAPID SCAN MODE THIS AFTERNOON AND IS NICELY SHOWING SOME
ENHANCEMENT TO THE CUMULUS FIELD RIGHT ALONG THE IMMEDIATE FRONTAL
BOUNDARY. IN GENERAL THE CUMULUS FIELD ON SATELLITE AND OUT THE
WINDOW LOOKS VERY MUSHY AND LACKING VERTICAL GROWTH...LIKELY DUE
IN LARGE PART TO THE VERY FORMIDABLE CAP EVIDENT ON DVN/ILX MORNING
SOUNDINGS AND STILL PRESENT IN RECENT ACARS SOUNDINGS OUT OF ORD
AND MDW. CONTINUED HEATING AND DESTABILIZATION OF THE BOUNDARY
LAYER ALONG WITH FORCED ASCENT ALONG THE FRONT SHOULD EVENTUALLY
CAUSE CAP TO BUST...BUT LIKELY NOT UNTIL THE FRONT IS AT LEAST TO
A CHICAGO TO PERU LINE IF NOT FARTHER SOUTHEAST. WILL BE REWORKING
POP GRIDS TO BETTER REFLECT THIS LINE OF THINKING...INCLUDING VERY
LITTLE THREAT OF PRECIP OVER NORTHWEST CWA AND STEADILY DECREASING
CHANCE FROM THE NORTHWEST SPREADING ACROSS THE AREA THIS
AFTERNOON. POST FRONT RAIN STILL A DISTINCT POSSIBILITY THIS
EVENING INTO TONIGHT AS AFOREMENTIONED KS/NE SHORTWAVE TRACKS
NORTHEAST INTO THE REGION.
IZZI
.MEDIUM AND LONG TERM DISCUSSION...
305 PM CDT...
FOR THE REMAINDER OF THE SHORT TERM...SATURDAY AND SUNDAY...THE
SURFACE COLD FRONT SHOULD PUSH SOUTHEAST OF THE CWA THROUGH THE OHIO
VALLEY. HOWEVER...GIVEN THAT THE BULK OF THE PCPN SHOULD BE ALONG
AND BEHIND THE BOUNDARY...THERE WILL LIKELY BE SOME LINGERING
SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM OVER THE FAR
SOUTHEASTERN PORTION OF THE CWA...MAINLY AROUND BENTON COUNTY...
INDIANA. THROUGH THE DAY ON SATURDAY...HIGH PRESSURE WILL SPREAD
FROM THE CENTRAL PLAINS...ACROSS THE MIDDLE MISSISSIPPI VALLEY AND
INTO THE MIDWEST. FOLLOWING THE FROPA AND AS THE HIGH SPREADS
ACROSS THE REGION...MOISTURE WILL DIMINISH MARKEDLY...WITH DEWPOINTS
DROPPING THROUGH THE 50S ON SATURDAY AND EVEN INTO THE UPPER 40S BY
SUNDAY. TEMPERATURES ON SATURDAY WILL BE AT LEAST 10 DEGREES LOWER
THAN ON FRIDAY...ONLY IN THE LOWER 70S. UNDER FULL SUNSHINE AND
WITH LOW DEWPOINTS...TEMPERATURES ON SUNDAY SHOULD BE ABLE TO
REBOUND BACK INTO THE MIDDLE TO UPPER 70S. SO AFTER A LITTLE PCPN
OVER THE FAR SERN PORTION OF THE CWA SATURDAY MORNING...THE
REMAINDER OF THE WEEKEND SHOULD BE QUITE PLEASANT.
FOR THE LONGER TERM...FROM MONDAY THROUGH FRIDAY...EXPECT MONDAY TO
START OUT COOL AND DRY WITH LOWS IN THE LOWER 50S. HOWEVER...
ANOTHER SYSTEM IS EXPECTED TO TAKE SHAPE OVER THE CENTRAL PLAINS.
AS THE HIGH SHIFTS OFF TO THE EAST AND LOW PRESSURE DEVELOPS OVER
THE PLAINS...A RETURN FLOW OF MOISTURE WILL SET UP. THROUGH THE
DAY...INCREASING WARM/MOIST ADVECTION WILL INCREASE AS A WARM FRONT
ALSO LIFTS NORTH TROUGH THE REGION. EXPECT THAT THE NEXT ROUND OF
PCPN SHOULD SPREAD INTO THE WRN PORTIONS OF THE CWA BY MONDAY
EVENING AND CONTINUE TO SPREAD EAST ACROSS THE REMAINDER OF THE CWA
THROUGH MONDAY NIGHT AND INTO TUESDAY MORNING. THE FORECAST PICTURE
BECOMES A BIT MORE MUDDLED INTO MID WEEK AS THE LARGER SCALE MODELS
BEGIN TO DIVERGE IN THEIR SOLUTIONS...WHICH WILL HAVE A BIG IMPACT
ON THE SENSIBLE WEATHER FORECAST. THE ECMWF WANTS TO DEVELOP A
DEEPER LOW IN ASSOCIATION WITH A NRN STREAM SHORT WAVE WHILE THE GFS
IS QUICKER AND WEAKER. SINCE THE UPPER LEVEL PATTERN IS EXPECTED TO
REMAIN VERY CLOSE TO ZONAL...WITH AN UPPER RIDGE ACROSS THE SRN
CONUS ANS AND VERY BROAD TROUGHING OVER THE NRN CONUS...AND THE
FASTER WLYS ACROSS THE NRN PLAINS/GREAT LAKES REGION...HAVE TRENDED
CLOSER TO THE FASTER GFS SOLUTION AS THE ZONAL FLOW PATTERN ALOFT
WOULD FAVOR A FASTER SOLUTION. HOWEVER...THE CAVEAT HERE IS THAT IN
FAST...ZONAL FLOW...FORECAST ERRORS CAN MAGNIFY QUICKLY...
PARTICULARLY IN THE TIMING OF THE SYSTEM...SO...EVEN THOUGH A FASTER
SOLUTION WOULD MAKE SENSE...THE TIMING UNCERTAINTIES ASSOCIATED WITH
FAST ZONAL FLOW ALOFT INTRODUCES LOWER CONFIDENCE IN THE END
PRODUCTS. BY FRIDAY...AT THE END OF THE FORECAST PERIOD...THE
LONGER RANGE MODELS WANT TO CARVE OUT A SHARPER TROUGH ALOFT AND
BRING MUCH COOLER AIR INTO THE REGION. THE GFS IS ADVERTISING HIGH
TEMPS ON FRIDAY ONLY IN THE LOWER TO MIDDLE 50S. THE OLD 00Z RUN OF
THE ECMWF HAD ALSO BEEN INDICATING HIGHS ON FRIDAY ONLY IN THE LOWER
TO MIDDLE 50S...BUT THE NEW 12Z HAS BACKED OFF ON THIS A BIT AND IS
NOW INDICATING HIGHS IN THE UPPER 50S TO LOWER 60S. AT THAT TIME
RANGE...THE MOS BASED PRODUCTS ARE LIKELY TRENDING TOO CLOSE TO
CLIMATOLOGY...WITH HIGHS IN THE MIDDLE TO UPPER 60S. SO...HAVE
TRENDED THE FORECAST MAX TEMPS FOR NEXT FRIDAY IN THE LOWER
60S...BUT IT WILL BE INTERESTING TO SEE HOW THIS PLAYS OUT AND IF
THE REGIONS SEES THE FIRST SHOT OF AUTUMNAL WEATHER.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* PATCHY MVFR CIGS IN 2500-3000 FT RANGE PRIOR TO SUNRISE.
* NORTHWEST WINDS LESS THAN 10 KT BECOMING NORTHEAST LATE THIS
AFTERNOON WITH LAKE BREEZE.
RATZER
//DISCUSSION...UPDATED 06Z...
COLD FRONT HAS PUSHED WELL SOUTHEAST OF TERMINALS AS OF MIDNIGHT
WITH SHOWERS HAVING ALSO GENERALLY ALONG/SOUTHEAST OF A KSPI-KIKK-
KSBN LINE AT 06Z. LOWER VFR CIGS IN THE 3500-6000 FT RANGE LINGER
ACROSS CHICAGO AREA...WITH SOME PATCHY SCT/BKN MVFR IN THE
2000-3000 FT RANGE ALSO NOTED ACROSS THE CITY (KORD-KMDW-KGYY).
FORECAST SOUNDINGS CONTINUE TO INDICATE SLOW BUT STEADY DRY
ADVECTION ON LIGHT NORTHWEST WINDS...WITH DRYING RESULTING IN
EROSION OF MVFR LEVEL CLOUDS PRIOR TO SUNRISE. CONTINUED DRYING OF
THE COLUMN AFTER SUNRISE IS EXPECTED TO YIELD VFR CONDITIONS
THROUGH REMAINDER OF FORECAST.
HIGH PRESSURE RIDGE AXIS BUILDS SOUTHEAST FROM WISCONSIN THIS
AFTERNOON WITH WEAKER GRADIENT EXPECTED TO SUPPORT A SHIFT FROM
LIGHT NORTH-NORTHWEST OR NORTH WINDS TO NORTHEAST WINDS AS A LAKE
BREEZE DEVELOPS LATE THIS AFTERNOON OR BY EVENING. HIGH-RES MODEL
WINDS DEPICT THIS MORE FULLY FOR KGYY AND KMDW...WITH A LITTLE
LESS CONFIDENCE OF INLAND PUSH AT KORD...THOUGH A WEAKENING NORTH
GRADIENT TYPICALLY SUPPORTS SUCH A LAKE BREEZE PUSH. IN ANY CASE
PREVAILING WINDS SHOULD BE UNDER 10 KT...DECREASING TO LESS THAN 5
KT AND BECOMING WEST-SOUTHWEST AFTER SUNSET.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN TIMING SHIFT TO NORTHEAST WINDS WITH LAKE
BREEZE.
* HIGH CONFIDENCE ALL OTHER FORECAST ELEMENTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY THROUGH MONDAY...VFR.
TUESDAY THROUGH THURSDAY...PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS.
BMD
&&
.MARINE...
229 PM CDT
WINDS WILL TURN NORTHWEST THIS EVENING AND THEN NORTH TONIGHT AND
TOMORROW BEHIND A PASSING COLD FRONT. WARM WATER AND COOL AIR WILL
ALLOW WINDS TO MIX DOWN EFFICIENTLY BUT THE GRADIENT IS NOT
ESPECIALLY STRONG SO DO NOT ANTICIPATE EXCESSIVE WAVE GROWTH OR
ANYTHING APPROACHING GALES EXCEPT FOR GUSTS NEAR STRONG STORMS
THIS EVENING. TOMORROW AFTERNOON THE NORTH WINDS BEGIN TO BACK
WEST AGAIN WHICH WILL ALLOW WAVE GROWTH TO BEGIN TAPERING OFF LATE
IN THE DAY. ANOTHER WEAKER TROUGH OR FRONT CROSSES THE LAKE
SATURDAY NIGHT...SO WINDS WILL BE VARIABLE FROM SOUTHWEST AHEAD OF
IT TO NORTHWEST BEHIND IT...BUT HIGH PRESSURE AND QUIET WEATHER
WILL BE THE MAIN STORY FOR THE OPEN WATERS THIS WEEKEND AFTER THIS
EVENING AND TONIGHT. IN THE NEARSHORE THERE WILL BE A PERIOD LATE
TONIGHT AND TOMORROW MORNING WHERE WAVES AND WINDS IN THE INDIANA
NEARSHORE WILL LIKELY SUPPORT SMALL CRAFT ADVISORY CONDITIONS.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 7 PM SATURDAY.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 7 PM SATURDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1208 AM CDT Sat Sep 6 2014
.UPDATE...
ISSUED AT 825 PM CDT FRI SEP 5 2014
01z radar imagery shows leading edge of strong convection along a
Paris to Shelbyville line moving eastward at around 40mph. Outflow
boundary has pushed out ahead of the line, so other than gusty
40-45 mph winds along the outflow, severe weather threat is
diminishing. The far eastern portion of Severe Thunderstorm Watch
496 still remains in effect, but will likely be canceled within
the next hour or two. Behind the main line of storms, scattered
showers and isolated thunderstorms extend as far west as the
Mississippi River. Still a few stronger storms across central
Missouri: however, these will weaken as well as they track across
the St. Louis area into south-central Illinois later this evening.
Have updated the forecast to reduce PoPs and go with only an
isolated thunder mention across the W/NW KILX CWA. Further south
and east of the main line, will stick with categorical thunder
through midnight.
&&
.SHORT TERM...(Tonight)
ISSUED AT 259 PM CDT FRI SEP 5 2014
Cold front moving into the Illinois River Valley this afternoon with
plenty of warm and moist air ahead of it. CAPEs ahead of the
boundary are in excess of 4000 J/kg, but shear is minimal and the cu
field has not yet responded to a lot of the heat of the day. Most
of the activity associated with the boundary is actually well behind
it, co-located with the best shear, but little in the way of CAPE.
The activity that initiated along boundary just to the north is
actually far more diurnally supported as it races out ahead of it.
Convection will have plenty of PW to work with in the column should
any storms develop, resulting in high precip and a threat for some
precip loading/small microbursts and associated damaging winds. So
far, remaining in the Slight Risk, but just outside a watch.
Updating the pops to increase invof the boundary through sunset,
then spreading out a bit more after sundown as the boundary moves
through the region overnight. Temperatures starting to drop at GBG,
so the temp curve tonight will vary a bit from diurnal and the lows
will vary somewhat nw of the Illinois River Valley should any clear
pockets develop. But llvl moisture hanging around quite a bit with
the precip behind the front should prevent too much of a drop.
&&
.LONG TERM...(Saturday through Friday)
ISSUED AT 259 PM CDT FRI SEP 5 2014
The cold front will be clear of the forecast area by Saturday
morning. This should take most of the precipitation risk with it.
However, have maintained some morning showers south of I-70, as much
of the precipitation with this front will be on the cool side of the
front with the better upper forcing. Aside from the slight morning
risk of rainfall in our southeast counties, the balance of the
weekend into early next week will offer quiet and cooler than normal
weather as Canadian high pressure builds into the area.
From Tuesday through the end of the period the relatively zonal flow
across the lower 48 will trend increasingly cyclonic as troffing
develops. Model agreement of the disturbances in this developing
trof is not that great as far as specifics. However, there is
general agreement that Tuesday-Thursday will feature periodic
showers/storms and remain cooler than normal. It also appears that a
much cooler area of high pressure will help dry things out by
Friday, with high temperatures by then possibly not making it out of
the 60s for at least a day or two.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1151 PM CDT FRI SEP 5 2014
Models have been a little slow in clearing precip from terminals
this evening. HRRR is picking up on weak trough associated with
low VFR clouds north of KPIA and KBMI. A few sites have dropped
blo MVFR along trough with a slight shift to a less of a westerly
component. A bit concerned that with precip this evening and
dropping winds in middle of trough might produce some lowered
vsbys. Will include a mention of tempo 5sm in KPIA and KBMI but
later shifts will need to keep a close eye on trend.
Cold advection will continue during the day tomorrow with gradual
clearing from north to south. Skies should be SKC after sunset.
Smith
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BARNES
SHORT TERM...HJS
LONG TERM...BAK
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS JACKSON KY
137 PM EDT SAT SEP 6 2014
.UPDATE...
ISSUED AT 1148 AM EDT SAT SEP 6 2014
LATEST MESOANALYSIS SHOWS WEAK SURFACE CONVERGENCE ACROSS THE
CENTRAL PART OF THE FORECAST AREA. THIS IS AHEAD OF THE APPROACHING
COLD FRONT WHICH HAS MOVED INTO NORTHERN KY. SBCAPE IN EXCESS OF 2500
J/KG ALSO ACROSS THE CENTRAL PART OF THE FORECAST AREA. CURRENT
THINKING IS THAT CONVECTION WILL INITIATE EARLY THIS AFTERNOON WHERE
THE LOW LEVEL CONVERGENCE COINCIDES WITH THE GREATEST CAPE. THIS IDEA
IS ALSO SUPPORTED BY THE 14Z HRRR. HAVE ADJUSTED NDFD AND ASSOCIATED
FORECAST PRODUCTS ACCORDINGLY. THERE IS ALSO SOME RAIN OCCURRING
BEHIND THE FRONT...AND THE 12Z NAM AND 14Z HRRR BRING PRECIPITATION
INTO THE NORTHERN PART OF THE FORECAST AREA AS WELL...EVEN THOUGH THE
INITIAL CONVECTIVE DEVELOPMENT THROUGH MID AFTERNOON SHOULD BE
FOCUSED IN THE CENTRAL PART OF THE FORECAST AREA. ONCE SHOWERS AND
THUNDERSTORMS DEVELOP THIS AFTERNOON CURRENT STORM MOTION FORECAST
WILL RESULT IN MOVEMENT TO THE SOUTHEAST AT 10 TO 15 MPH.
UPDATE ISSUED AT 953 AM EDT SAT SEP 6 2014
UPDATED HOURLY NDFD BASED ON LATEST OBSERVATIONAL AND MODEL TRENDS.
HAVE LOWERED THUNDERSTORM CHANCES FOR THE NEXT COUPLE OF HOURS
FOLLOWING THE LATEST HRRR AND SATELLITE AND RADAR TRENDS. LOCALLY
DENSE FOG HAS LIFTED AND HAVE UPDATED ZFP TO REMOVE MENTION OF
MORNING FOG. 12Z SOUNDINGS SHOWING PWS OF AROUND 1.6 INCHES SO
LOCALLY HEAVY RAINS STILL LOOK POSSIBLE AS NOTED IN THE HWO.
UPDATE ISSUED AT 730 AM EDT SAT SEP 6 2014
DID A QUICK UPDATE TO THE GRIDS TO REFLECT THE CURRENT RADAR
OBSERVATIONS AND TRENDS WITH RESPECT TO POPS AND WX. THE LATEST HRRR
DOESN/T REALLY GET THINGS GOING AROUND HERE UNTIL AFTER 18Z SO HAVE
TRENDED TOWARD THAT IDEA. ALSO...FINE TUNED THE T/TD ONES PER THE
OBS AND TRENDS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 350 AM EDT SAT SEP 6 2014
07Z SFC ANALYSIS SHOWS AN AREA OF LOW PRESSURE MOVING THROUGH EASTERN
CANADA WITH A TRAILING COLD FRONT RUNNING SOUTHWEST THROUGH THE OHIO
VALLEY AND INTO SOUTHERN MISSOURI. THE REMAINS OF A SQUALL LINE HAS
SETTLED JUST SOUTH OF THE OHIO RIVER...OUT AHEAD OF THE COLD FRONT. A
FEW LINGERING SHOWERS REMAIN WITH THIS AS IT CONTINUES TO FADE OUT
WITH ITS APPROACH TO THE JKL CWA. ON SATELLITE...MID AND HIGH LEVEL
CLOUDS COVER THE OHIO VALLEY NORTH AND WEST OF THIS OUTFLOW BOUNDARY.
HOWEVER...THE CLEARER SKIES TO THE SOUTH HAS ALLOWED AREAS OF FOG TO
DEVELOP THROUGH EAST KENTUCKY WITH LOCALLY DENSE PATCHES IN THE
VALLEYS. HIGH DEWPOINTS IN THE UPPER 60S AND LOWER 70S ARE PROVIDING
A FLOOR TO THE COOLING THIS NIGHT WITH JUST A SMALL RIDGE AND VALLEY
SPLIT EVIDENT WITH READINGS VARYING FROM LOWER 70S IN THE THERMAL
BELT TO THE UPPER 60S IN THE LOW SPOTS. WINDS REMAIN LIGHT TO CALM
THROUGH THE AREA.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS
HEIGHTS FALL OVER THE OHIO VALLEY IN RESPONSE TO A BROAD TROUGH
MOVING THROUGH THE NORTHEAST PORTION OF THE CONTINENT. THE ENERGY
STREAM ASSOCIATED WITH THIS MOVES QUICKLY INTO THE SOUTHERN OHIO
VALLEY TODAY...BUT THEN LINGERS OVERHEAD THROUGH THE WEEKEND WITH A
BIT OF A RESURGENCE LATER SUNDAY. GIVEN THE GOOD MODEL AGREEMENT...
FOR WEATHER SPECIFICS HAVE FAVORED A BLEND OF THE HRRR AND NAM12
THROUGH THE FIRST HALF OF THE SHORT TERM FOLLOWED BY A MIX OF THE NAM
AND LATEST ECMWF SOLUTIONS.
SENSIBLE WEATHER WILL FEATURE AREAS OF FOG...LOCALLY DENSE...BURNING
OFF EARLY THIS MORNING. THIS WILL BE FOLLOWED BY THE ARRIVAL OF
SHOWERS AND THUNDERSTORMS BY MID AFTERNOON FROM NORTH TO SOUTH AS A
COLD FRONT PRESSES SOUTH INTO THE AREA. PWS WITH THIS CONVECTION WILL
BE MODERATELY HIGH WHILE STORM MOTION STARTS TO SPEED UP AS THE DAY
WEARS ON. THIS SHOULD LIMIT THE RISK FOR FLASH FLOODING WHEN COMPARED
TO THE PAST SEVERAL DAYS. HOWEVER...A LOCALIZED THREAT FOR HEAVY RAIN
WILL REMAIN SHOULD TRAINING DEVELOP IN ANY PARTICULARLY LOCATION.
THE THUNDER IS ANTICIPATED TO FADE FROM THE CONVECTION LATER TONIGHT
AS THE FRONT SINKS SOUTH OF AREA LEAVING JUST A FEW LIGHT SHOWERS
TRAILING BEHIND. FOR SUNDAY...THE NEARBY FRONT MAY CAUSE A SHOWER OR
TWO TO POP UP OVER FAR SOUTHEAST KENTUCKY WHILE THE BOUNDARY SLOWS
IN RESPONSE TO A BUCKLE IN THE MID LEVEL FLOW AND A DEVELOPING WAVE
AT THE SFC ALONG THE GEORGIA COAST. THE WARMTH AND STICKY HUMIDITY
WILL LEAVE THE AREA...AT LEAST FOR A COUPLE OF DAYS...ONCE THE FRONT
MOVES THROUGH MEANING THAT SUNDAY WILL BE A MUCH MORE COMFORTABLE DAY
THAN TODAY AND ALSO PROVIDE A HINT OF THE FALL-LIKE WEATHER THAT
COULD ARRIVE IN EARNEST LATER IN THE WEEK.
FOR TEMPERATURES...DEWPOINTS...AND WINDS...USED THE CONSSHORT FOR
THE FIRST 24 HOURS AND THEN THE SUPERBLEND THROUGH SUNDAY. DID MAKE
SOME MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS TONIGHT. AS
FOR POPS ENDED UP ON THE HIGH SIDE OF MOS GUIDANCE TODAY...COUNTING
ON MOST OF THE AREA MEASURING AS THIS FRONT MOVES THROUGH GIVEN THE
FAIRLY HIGH MOISTURE CONTENT IN PLACE. WAS SIMILAR TO THE GUIDANCE
TONIGHT AND SUNDAY...LIMITING THE CHANCE POPS TO THE FAR SOUTHEAST.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 335 AM EDT SAT SEP 6 2014
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT IN REGARDS TO A
SIGNIFICANT PATTERN CHANGE FOR THE END OF NEXT WEEK...WITH A MAJOR
COOL DOWN IN STORE. HOWEVER...THE MODELS DIFFER IN HOW THEY HANDLE
THE EVOLUTION OF WEATHER SYSTEMS THAT WILL BRING SHOWERS AND STORMS
TO EASTERN KENTUCKY DURING THE UPCOMING WORK WEEK. THE PERIOD WILL
START OUT WARM AND DRY AS HIGH PRESSURE SUNDAY NIGHT THROUGH
TUESDAY. THERE IS A POSSIBILITY OF SCATTERED SHOWERS AND STORMS
FORMING BENEATH THE RIDGE ON MONDAY...AS MOISTURE OFF THE GULF OF
MEXICO GETS DRAWN INTO THE AREA BY A WEAK AREA OF LOW PRESSURE THAT
IS PROGGED TO PASS ACROSS THE TENNESSEE VALLEY. THE ECMWF WAS SLOWER
AND WETTER THAN THE GFS FROM WEDNESDAY ONWARD. BOTH MODELS HAVE A
COLD FRONT MOVING ACROSS THE OHIO AND TENNESSEE VALLEY REGIONS
WEDNESDAY THROUGH FRIDAY...WITH SCATTERED SHOWERS AND STORMS FORMING
IN THE VICINITY OF THE BOUNDARY. WITH UNCERTAINTY BETWEEN THE
MODELS...DECIDED TO USE A BLEND OF THE ECMWF AND GFS MODELS...WITH A
SLIGHT BIAS TOWARD TO NORMALLY MORE RELIABLE ECMWF SOLUTION. THE
BEST CHANCES FOR RAIN WILL COME FROM LATE WEDNESDAY NIGHT THROUGH
THURSDAY EVENING DURING FRONTAL PASSAGE.
TEMPERATURES THE FIRST FEW DAYS OF THE PERIOD LOOK TO BE AT OR
SLIGHT BELOW NORMAL...DUE TO THE INFLUENCE OF NORTHERLY FLOW...CLOUD
COVER...AND PRECIPITATION ASSOCIATED WITH AN AREA OF LOW PRESSURE
THAT IS EXPECTED TO PASS THROUGH THE TENNESSEE VALLEY ON MONDAY.
HIGHS ON MONDAY ARE EXPECTED TO TOP OUT AROUND 80...WITH READINGS
MAXING OUT IN THE LOW TO MID 80S ON TUESDAY AND WEDNESDAY. THE BIG
PATTERN CHANGE LOOKS LIKE IT WILL TAKE PLACE FROM THURSDAY
ONWARD...AS A COOL CANADIAN AIR MASS SETTLES OVER THE REGION BEHIND
A DEPARTING AND VERY POTENT COLD FRONT. HIGHS ON FRIDAY MIGHT ONLY
TOP OUT IN THE LOW TO MID 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 136 PM EDT SAT SEP 6 2014
A BROKEN LINE OF THUNDERSTORMS AHEAD OF AN APPROACHING COLD FRONT
WILL AFFECT ALL TAF SITES THIS AFTERNOON. THE THUNDERSTORMS WILL EXIT
THE FORECAST AREA BY 00Z THIS EVENING. OUTSIDE OF THUNDERSTORMS VFR
CONDITIONS WILL PREVAIL ACROSS THE AREA...BUT THERE WILL BE LOCAL
SPOTS WITH MVFR CEILINGS. AFTER THE COLD FRONT PASSAGE EXTENSIVE LOW
CLOUDINESS WILL SPREAD ACROSS THE AREA TONIGHT...WITH WIDESPREAD MVFR
CEILINGS EXPECTED TO PERSIST INTO THE DAY ON SUNDAY. VFR CONDITIONS
SHOULD RETURN LATE SUNDAY AFTERNOON...AS CLOUDS LIFT AND BEGIN TO
DECREASE IN COVERAGE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS JACKSON KY
1149 AM EDT SAT SEP 6 2014
.UPDATE...
ISSUED AT 1148 AM EDT SAT SEP 6 2014
LATEST MESOANALYSIS SHOWS WEAK SURFACE CONVERGENCE ACROSS THE
CENTRAL PART OF THE FORECAST AREA. THIS IS AHEAD OF THE APPROACHING
COLD FRONT WHICH HAS MOVED INTO NORTHERN KY. SBCAPE IN EXCESS OF 2500
J/KG ALSO ACROSS THE CENTRAL PART OF THE FORECAST AREA. CURRENT
THINKING IS THAT CONVECTION WILL INITIATE EARLY THIS AFTERNOON WHERE
THE LOW LEVEL CONVERGENCE COINCIDES WITH THE GREATEST CAPE. THIS IDEA
IS ALSO SUPPORTED BY THE 14Z HRRR. HAVE ADJUSTED NDFD AND ASSOCIATED
FORECAST PRODUCTS ACCORDINGLY. THERE IS ALSO SOME RAIN OCCURRING
BEHIND THE FRONT...AND THE 12Z NAM AND 14Z HRRR BRING PRECIPITATION
INTO THE NORTHERN PART OF THE FORECAST AREA AS WELL...EVEN THOUGH THE
INITIAL CONVECTIVE DEVELOPMENT THROUGH MID AFTERNOON SHOULD BE
FOCUSED IN THE CENTRAL PART OF THE FORECAST AREA. ONCE SHOWERS AND
THUNDERSTORMS DEVELOP THIS AFTERNOON CURRENT STORM MOTION FORECAST
WILL RESULT IN MOVEMENT TO THE SOUTHEAST AT 10 TO 15 MPH.
UPDATE ISSUED AT 953 AM EDT SAT SEP 6 2014
UPDATED HOURLY NDFD BASED ON LATEST OBSERVATIONAL AND MODEL TRENDS.
HAVE LOWERED THUNDERSTORM CHANCES FOR THE NEXT COUPLE OF HOURS
FOLLOWING THE LATEST HRRR AND SATELLITE AND RADAR TRENDS. LOCALLY
DENSE FOG HAS LIFTED AND HAVE UPDATED ZFP TO REMOVE MENTION OF
MORNING FOG. 12Z SOUNDINGS SHOWING PWS OF AROUND 1.6 INCHES SO
LOCALLY HEAVY RAINS STILL LOOK POSSIBLE AS NOTED IN THE HWO.
UPDATE ISSUED AT 730 AM EDT SAT SEP 6 2014
DID A QUICK UPDATE TO THE GRIDS TO REFLECT THE CURRENT RADAR
OBSERVATIONS AND TRENDS WITH RESPECT TO POPS AND WX. THE LATEST HRRR
DOESN/T REALLY GET THINGS GOING AROUND HERE UNTIL AFTER 18Z SO HAVE
TRENDED TOWARD THAT IDEA. ALSO...FINE TUNED THE T/TD ONES PER THE
OBS AND TRENDS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 350 AM EDT SAT SEP 6 2014
07Z SFC ANALYSIS SHOWS AN AREA OF LOW PRESSURE MOVING THROUGH EASTERN
CANADA WITH A TRAILING COLD FRONT RUNNING SOUTHWEST THROUGH THE OHIO
VALLEY AND INTO SOUTHERN MISSOURI. THE REMAINS OF A SQUALL LINE HAS
SETTLED JUST SOUTH OF THE OHIO RIVER...OUT AHEAD OF THE COLD FRONT. A
FEW LINGERING SHOWERS REMAIN WITH THIS AS IT CONTINUES TO FADE OUT
WITH ITS APPROACH TO THE JKL CWA. ON SATELLITE...MID AND HIGH LEVEL
CLOUDS COVER THE OHIO VALLEY NORTH AND WEST OF THIS OUTFLOW BOUNDARY.
HOWEVER...THE CLEARER SKIES TO THE SOUTH HAS ALLOWED AREAS OF FOG TO
DEVELOP THROUGH EAST KENTUCKY WITH LOCALLY DENSE PATCHES IN THE
VALLEYS. HIGH DEWPOINTS IN THE UPPER 60S AND LOWER 70S ARE PROVIDING
A FLOOR TO THE COOLING THIS NIGHT WITH JUST A SMALL RIDGE AND VALLEY
SPLIT EVIDENT WITH READINGS VARYING FROM LOWER 70S IN THE THERMAL
BELT TO THE UPPER 60S IN THE LOW SPOTS. WINDS REMAIN LIGHT TO CALM
THROUGH THE AREA.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS
HEIGHTS FALL OVER THE OHIO VALLEY IN RESPONSE TO A BROAD TROUGH
MOVING THROUGH THE NORTHEAST PORTION OF THE CONTINENT. THE ENERGY
STREAM ASSOCIATED WITH THIS MOVES QUICKLY INTO THE SOUTHERN OHIO
VALLEY TODAY...BUT THEN LINGERS OVERHEAD THROUGH THE WEEKEND WITH A
BIT OF A RESURGENCE LATER SUNDAY. GIVEN THE GOOD MODEL AGREEMENT...
FOR WEATHER SPECIFICS HAVE FAVORED A BLEND OF THE HRRR AND NAM12
THROUGH THE FIRST HALF OF THE SHORT TERM FOLLOWED BY A MIX OF THE NAM
AND LATEST ECMWF SOLUTIONS.
SENSIBLE WEATHER WILL FEATURE AREAS OF FOG...LOCALLY DENSE...BURNING
OFF EARLY THIS MORNING. THIS WILL BE FOLLOWED BY THE ARRIVAL OF
SHOWERS AND THUNDERSTORMS BY MID AFTERNOON FROM NORTH TO SOUTH AS A
COLD FRONT PRESSES SOUTH INTO THE AREA. PWS WITH THIS CONVECTION WILL
BE MODERATELY HIGH WHILE STORM MOTION STARTS TO SPEED UP AS THE DAY
WEARS ON. THIS SHOULD LIMIT THE RISK FOR FLASH FLOODING WHEN COMPARED
TO THE PAST SEVERAL DAYS. HOWEVER...A LOCALIZED THREAT FOR HEAVY RAIN
WILL REMAIN SHOULD TRAINING DEVELOP IN ANY PARTICULARLY LOCATION.
THE THUNDER IS ANTICIPATED TO FADE FROM THE CONVECTION LATER TONIGHT
AS THE FRONT SINKS SOUTH OF AREA LEAVING JUST A FEW LIGHT SHOWERS
TRAILING BEHIND. FOR SUNDAY...THE NEARBY FRONT MAY CAUSE A SHOWER OR
TWO TO POP UP OVER FAR SOUTHEAST KENTUCKY WHILE THE BOUNDARY SLOWS
IN RESPONSE TO A BUCKLE IN THE MID LEVEL FLOW AND A DEVELOPING WAVE
AT THE SFC ALONG THE GEORGIA COAST. THE WARMTH AND STICKY HUMIDITY
WILL LEAVE THE AREA...AT LEAST FOR A COUPLE OF DAYS...ONCE THE FRONT
MOVES THROUGH MEANING THAT SUNDAY WILL BE A MUCH MORE COMFORTABLE DAY
THAN TODAY AND ALSO PROVIDE A HINT OF THE FALL-LIKE WEATHER THAT
COULD ARRIVE IN EARNEST LATER IN THE WEEK.
FOR TEMPERATURES...DEWPOINTS...AND WINDS...USED THE CONSSHORT FOR
THE FIRST 24 HOURS AND THEN THE SUPERBLEND THROUGH SUNDAY. DID MAKE
SOME MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS TONIGHT. AS
FOR POPS ENDED UP ON THE HIGH SIDE OF MOS GUIDANCE TODAY...COUNTING
ON MOST OF THE AREA MEASURING AS THIS FRONT MOVES THROUGH GIVEN THE
FAIRLY HIGH MOISTURE CONTENT IN PLACE. WAS SIMILAR TO THE GUIDANCE
TONIGHT AND SUNDAY...LIMITING THE CHANCE POPS TO THE FAR SOUTHEAST.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 335 AM EDT SAT SEP 6 2014
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT IN REGARDS TO A
SIGNIFICANT PATTERN CHANGE FOR THE END OF NEXT WEEK...WITH A MAJOR
COOL DOWN IN STORE. HOWEVER...THE MODELS DIFFER IN HOW THEY HANDLE
THE EVOLUTION OF WEATHER SYSTEMS THAT WILL BRING SHOWERS AND STORMS
TO EASTERN KENTUCKY DURING THE UPCOMING WORK WEEK. THE PERIOD WILL
START OUT WARM AND DRY AS HIGH PRESSURE SUNDAY NIGHT THROUGH
TUESDAY. THERE IS A POSSIBILITY OF SCATTERED SHOWERS AND STORMS
FORMING BENEATH THE RIDGE ON MONDAY...AS MOISTURE OFF THE GULF OF
MEXICO GETS DRAWN INTO THE AREA BY A WEAK AREA OF LOW PRESSURE THAT
IS PROGGED TO PASS ACROSS THE TENNESSEE VALLEY. THE ECMWF WAS SLOWER
AND WETTER THAN THE GFS FROM WEDNESDAY ONWARD. BOTH MODELS HAVE A
COLD FRONT MOVING ACROSS THE OHIO AND TENNESSEE VALLEY REGIONS
WEDNESDAY THROUGH FRIDAY...WITH SCATTERED SHOWERS AND STORMS FORMING
IN THE VICINITY OF THE BOUNDARY. WITH UNCERTAINTY BETWEEN THE
MODELS...DECIDED TO USE A BLEND OF THE ECMWF AND GFS MODELS...WITH A
SLIGHT BIAS TOWARD TO NORMALLY MORE RELIABLE ECMWF SOLUTION. THE
BEST CHANCES FOR RAIN WILL COME FROM LATE WEDNESDAY NIGHT THROUGH
THURSDAY EVENING DURING FRONTAL PASSAGE.
TEMPERATURES THE FIRST FEW DAYS OF THE PERIOD LOOK TO BE AT OR
SLIGHT BELOW NORMAL...DUE TO THE INFLUENCE OF NORTHERLY FLOW...CLOUD
COVER...AND PRECIPITATION ASSOCIATED WITH AN AREA OF LOW PRESSURE
THAT IS EXPECTED TO PASS THROUGH THE TENNESSEE VALLEY ON MONDAY.
HIGHS ON MONDAY ARE EXPECTED TO TOP OUT AROUND 80...WITH READINGS
MAXING OUT IN THE LOW TO MID 80S ON TUESDAY AND WEDNESDAY. THE BIG
PATTERN CHANGE LOOKS LIKE IT WILL TAKE PLACE FROM THURSDAY
ONWARD...AS A COOL CANADIAN AIR MASS SETTLES OVER THE REGION BEHIND
A DEPARTING AND VERY POTENT COLD FRONT. HIGHS ON FRIDAY MIGHT ONLY
TOP OUT IN THE LOW TO MID 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 755 AM EDT SAT SEP 6 2014
THE FOG AT THE TAF SITES WILL LIFT AND DISSIPATING BY 1330Z.
BEST CHANCES OF CONVECTION SHOULD HOLD OFF UNTIL AT LEAST 15Z ACROSS
THE OFFICIAL TAF SITES TODAY...AWAITING THE NEARING APPROACH OF THE
COLD FRONT. WITH THE HIGH PROBABILITIES OF CONVECTION ALONG THE
FRONT...WENT WITH PREVAILING TSRA AND WITH THE LOWER...MVFR...
VIS/CIGS STARTING AT 15Z AT THE FARTHEST NW SITE /KSYM/...AND 17Z
AT THE SOUTHERN MOST SITE /KSME/ TO MATCH UP WITH ONGOING LIKELY TO
CATEGORICAL POPS IN THE FORECAST. JUST SOME SCATTERED SHOWERS FOLLOW
LATER THIS EVENING AT THE SITES WITH CIGS EXPECTED TO REMAIN IN THE
MVFR RANGE POST-FRONTAL. WINDS THROUGH THE BULK OF THE PERIOD WILL
BE LIGHT AND VARIABLE BUT SWITCH TO THE NORTH AND NORTHWEST AT 5 TO
10 KTS BEHIND THE FRONT AS IT DROPS SOUTH DURING THE DAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS JACKSON KY
953 AM EDT SAT SEP 6 2014
.UPDATE...
ISSUED AT 953 AM EDT SAT SEP 6 2014
UPDATED HOURLY NDFD BASED ON LATEST OBSERVATIONAL AND MODEL TRENDS.
HAVE LOWERED THUNDERSTORM CHANCES FOR THE NEXT COUPLE OF HOURS
FOLLOWING THE LATEST HRRR AND SATELLITE AND RADAR TRENDS. LOCALLY
DENSE FOG HAS LIFTED AND HAVE UPDATED ZFP TO REMOVE MENTION OF
MORNING FOG. 12Z SOUNDINGS SHOWING PWS OF AROUND 1.6 INCHES SO
LOCALLY HEAVY RAINS STILL LOOK POSSIBLE AS NOTED IN THE HWO.
UPDATE ISSUED AT 730 AM EDT SAT SEP 6 2014
DID A QUICK UPDATE TO THE GRIDS TO REFLECT THE CURRENT RADAR
OBSERVATIONS AND TRENDS WITH RESPECT TO POPS AND WX. THE LATEST HRRR
DOESN/T REALLY GET THINGS GOING AROUND HERE UNTIL AFTER 18Z SO HAVE
TRENDED TOWARD THAT IDEA. ALSO...FINE TUNED THE T/TD ONES PER THE
OBS AND TRENDS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 350 AM EDT SAT SEP 6 2014
07Z SFC ANALYSIS SHOWS AN AREA OF LOW PRESSURE MOVING THROUGH EASTERN
CANADA WITH A TRAILING COLD FRONT RUNNING SOUTHWEST THROUGH THE OHIO
VALLEY AND INTO SOUTHERN MISSOURI. THE REMAINS OF A SQUALL LINE HAS
SETTLED JUST SOUTH OF THE OHIO RIVER...OUT AHEAD OF THE COLD FRONT. A
FEW LINGERING SHOWERS REMAIN WITH THIS AS IT CONTINUES TO FADE OUT
WITH ITS APPROACH TO THE JKL CWA. ON SATELLITE...MID AND HIGH LEVEL
CLOUDS COVER THE OHIO VALLEY NORTH AND WEST OF THIS OUTFLOW BOUNDARY.
HOWEVER...THE CLEARER SKIES TO THE SOUTH HAS ALLOWED AREAS OF FOG TO
DEVELOP THROUGH EAST KENTUCKY WITH LOCALLY DENSE PATCHES IN THE
VALLEYS. HIGH DEWPOINTS IN THE UPPER 60S AND LOWER 70S ARE PROVIDING
A FLOOR TO THE COOLING THIS NIGHT WITH JUST A SMALL RIDGE AND VALLEY
SPLIT EVIDENT WITH READINGS VARYING FROM LOWER 70S IN THE THERMAL
BELT TO THE UPPER 60S IN THE LOW SPOTS. WINDS REMAIN LIGHT TO CALM
THROUGH THE AREA.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS
HEIGHTS FALL OVER THE OHIO VALLEY IN RESPONSE TO A BROAD TROUGH
MOVING THROUGH THE NORTHEAST PORTION OF THE CONTINENT. THE ENERGY
STREAM ASSOCIATED WITH THIS MOVES QUICKLY INTO THE SOUTHERN OHIO
VALLEY TODAY...BUT THEN LINGERS OVERHEAD THROUGH THE WEEKEND WITH A
BIT OF A RESURGENCE LATER SUNDAY. GIVEN THE GOOD MODEL AGREEMENT...
FOR WEATHER SPECIFICS HAVE FAVORED A BLEND OF THE HRRR AND NAM12
THROUGH THE FIRST HALF OF THE SHORT TERM FOLLOWED BY A MIX OF THE NAM
AND LATEST ECMWF SOLUTIONS.
SENSIBLE WEATHER WILL FEATURE AREAS OF FOG...LOCALLY DENSE...BURNING
OFF EARLY THIS MORNING. THIS WILL BE FOLLOWED BY THE ARRIVAL OF
SHOWERS AND THUNDERSTORMS BY MID AFTERNOON FROM NORTH TO SOUTH AS A
COLD FRONT PRESSES SOUTH INTO THE AREA. PWS WITH THIS CONVECTION WILL
BE MODERATELY HIGH WHILE STORM MOTION STARTS TO SPEED UP AS THE DAY
WEARS ON. THIS SHOULD LIMIT THE RISK FOR FLASH FLOODING WHEN COMPARED
TO THE PAST SEVERAL DAYS. HOWEVER...A LOCALIZED THREAT FOR HEAVY RAIN
WILL REMAIN SHOULD TRAINING DEVELOP IN ANY PARTICULARLY LOCATION.
THE THUNDER IS ANTICIPATED TO FADE FROM THE CONVECTION LATER TONIGHT
AS THE FRONT SINKS SOUTH OF AREA LEAVING JUST A FEW LIGHT SHOWERS
TRAILING BEHIND. FOR SUNDAY...THE NEARBY FRONT MAY CAUSE A SHOWER OR
TWO TO POP UP OVER FAR SOUTHEAST KENTUCKY WHILE THE BOUNDARY SLOWS
IN RESPONSE TO A BUCKLE IN THE MID LEVEL FLOW AND A DEVELOPING WAVE
AT THE SFC ALONG THE GEORGIA COAST. THE WARMTH AND STICKY HUMIDITY
WILL LEAVE THE AREA...AT LEAST FOR A COUPLE OF DAYS...ONCE THE FRONT
MOVES THROUGH MEANING THAT SUNDAY WILL BE A MUCH MORE COMFORTABLE DAY
THAN TODAY AND ALSO PROVIDE A HINT OF THE FALL-LIKE WEATHER THAT
COULD ARRIVE IN EARNEST LATER IN THE WEEK.
FOR TEMPERATURES...DEWPOINTS...AND WINDS...USED THE CONSSHORT FOR
THE FIRST 24 HOURS AND THEN THE SUPERBLEND THROUGH SUNDAY. DID MAKE
SOME MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS TONIGHT. AS
FOR POPS ENDED UP ON THE HIGH SIDE OF MOS GUIDANCE TODAY...COUNTING
ON MOST OF THE AREA MEASURING AS THIS FRONT MOVES THROUGH GIVEN THE
FAIRLY HIGH MOISTURE CONTENT IN PLACE. WAS SIMILAR TO THE GUIDANCE
TONIGHT AND SUNDAY...LIMITING THE CHANCE POPS TO THE FAR SOUTHEAST.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 335 AM EDT SAT SEP 6 2014
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT IN REGARDS TO A
SIGNIFICANT PATTERN CHANGE FOR THE END OF NEXT WEEK...WITH A MAJOR
COOL DOWN IN STORE. HOWEVER...THE MODELS DIFFER IN HOW THEY HANDLE
THE EVOLUTION OF WEATHER SYSTEMS THAT WILL BRING SHOWERS AND STORMS
TO EASTERN KENTUCKY DURING THE UPCOMING WORK WEEK. THE PERIOD WILL
START OUT WARM AND DRY AS HIGH PRESSURE SUNDAY NIGHT THROUGH
TUESDAY. THERE IS A POSSIBILITY OF SCATTERED SHOWERS AND STORMS
FORMING BENEATH THE RIDGE ON MONDAY...AS MOISTURE OFF THE GULF OF
MEXICO GETS DRAWN INTO THE AREA BY A WEAK AREA OF LOW PRESSURE THAT
IS PROGGED TO PASS ACROSS THE TENNESSEE VALLEY. THE ECMWF WAS SLOWER
AND WETTER THAN THE GFS FROM WEDNESDAY ONWARD. BOTH MODELS HAVE A
COLD FRONT MOVING ACROSS THE OHIO AND TENNESSEE VALLEY REGIONS
WEDNESDAY THROUGH FRIDAY...WITH SCATTERED SHOWERS AND STORMS FORMING
IN THE VICINITY OF THE BOUNDARY. WITH UNCERTAINTY BETWEEN THE
MODELS...DECIDED TO USE A BLEND OF THE ECMWF AND GFS MODELS...WITH A
SLIGHT BIAS TOWARD TO NORMALLY MORE RELIABLE ECMWF SOLUTION. THE
BEST CHANCES FOR RAIN WILL COME FROM LATE WEDNESDAY NIGHT THROUGH
THURSDAY EVENING DURING FRONTAL PASSAGE.
TEMPERATURES THE FIRST FEW DAYS OF THE PERIOD LOOK TO BE AT OR
SLIGHT BELOW NORMAL...DUE TO THE INFLUENCE OF NORTHERLY FLOW...CLOUD
COVER...AND PRECIPITATION ASSOCIATED WITH AN AREA OF LOW PRESSURE
THAT IS EXPECTED TO PASS THROUGH THE TENNESSEE VALLEY ON MONDAY.
HIGHS ON MONDAY ARE EXPECTED TO TOP OUT AROUND 80...WITH READINGS
MAXING OUT IN THE LOW TO MID 80S ON TUESDAY AND WEDNESDAY. THE BIG
PATTERN CHANGE LOOKS LIKE IT WILL TAKE PLACE FROM THURSDAY
ONWARD...AS A COOL CANADIAN AIR MASS SETTLES OVER THE REGION BEHIND
A DEPARTING AND VERY POTENT COLD FRONT. HIGHS ON FRIDAY MIGHT ONLY
TOP OUT IN THE LOW TO MID 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 755 AM EDT SAT SEP 6 2014
THE FOG AT THE TAF SITES WILL LIFT AND DISSIPATING BY 1330Z.
BEST CHANCES OF CONVECTION SHOULD HOLD OFF UNTIL AT LEAST 15Z ACROSS
THE OFFICIAL TAF SITES TODAY...AWAITING THE NEARING APPROACH OF THE
COLD FRONT. WITH THE HIGH PROBABILITIES OF CONVECTION ALONG THE
FRONT...WENT WITH PREVAILING TSRA AND WITH THE LOWER...MVFR...
VIS/CIGS STARTING AT 15Z AT THE FARTHEST NW SITE /KSYM/...AND 17Z
AT THE SOUTHERN MOST SITE /KSME/ TO MATCH UP WITH ONGOING LIKELY TO
CATEGORICAL POPS IN THE FORECAST. JUST SOME SCATTERED SHOWERS FOLLOW
LATER THIS EVENING AT THE SITES WITH CIGS EXPECTED TO REMAIN IN THE
MVFR RANGE POST-FRONTAL. WINDS THROUGH THE BULK OF THE PERIOD WILL
BE LIGHT AND VARIABLE BUT SWITCH TO THE NORTH AND NORTHWEST AT 5 TO
10 KTS BEHIND THE FRONT AS IT DROPS SOUTH DURING THE DAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
755 AM EDT SAT SEP 6 2014
.UPDATE...
ISSUED AT 730 AM EDT SAT SEP 6 2014
DID A QUICK UPDATE TO THE GRIDS TO REFLECT THE CURRENT RADAR
OBSERVATIONS AND TRENDS WITH RESPECT TO POPS AND WX. THE LATEST HRRR
DOESN/T REALLY GET THINGS GOING AROUND HERE UNTIL AFTER 18Z SO HAVE
TRENDED TOWARD THAT IDEA. ALSO...FINE TUNED THE T/TD ONES PER THE
OBS AND TRENDS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 350 AM EDT SAT SEP 6 2014
07Z SFC ANALYSIS SHOWS AN AREA OF LOW PRESSURE MOVING THROUGH EASTERN
CANADA WITH A TRAILING COLD FRONT RUNNING SOUTHWEST THROUGH THE OHIO
VALLEY AND INTO SOUTHERN MISSOURI. THE REMAINS OF A SQUALL LINE HAS
SETTLED JUST SOUTH OF THE OHIO RIVER...OUT AHEAD OF THE COLD FRONT. A
FEW LINGERING SHOWERS REMAIN WITH THIS AS IT CONTINUES TO FADE OUT
WITH ITS APPROACH TO THE JKL CWA. ON SATELLITE...MID AND HIGH LEVEL
CLOUDS COVER THE OHIO VALLEY NORTH AND WEST OF THIS OUTFLOW BOUNDARY.
HOWEVER...THE CLEARER SKIES TO THE SOUTH HAS ALLOWED AREAS OF FOG TO
DEVELOP THROUGH EAST KENTUCKY WITH LOCALLY DENSE PATCHES IN THE
VALLEYS. HIGH DEWPOINTS IN THE UPPER 60S AND LOWER 70S ARE PROVIDING
A FLOOR TO THE COOLING THIS NIGHT WITH JUST A SMALL RIDGE AND VALLEY
SPLIT EVIDENT WITH READINGS VARYING FROM LOWER 70S IN THE THERMAL
BELT TO THE UPPER 60S IN THE LOW SPOTS. WINDS REMAIN LIGHT TO CALM
THROUGH THE AREA.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS
HEIGHTS FALL OVER THE OHIO VALLEY IN RESPONSE TO A BROAD TROUGH
MOVING THROUGH THE NORTHEAST PORTION OF THE CONTINENT. THE ENERGY
STREAM ASSOCIATED WITH THIS MOVES QUICKLY INTO THE SOUTHERN OHIO
VALLEY TODAY...BUT THEN LINGERS OVERHEAD THROUGH THE WEEKEND WITH A
BIT OF A RESURGENCE LATER SUNDAY. GIVEN THE GOOD MODEL AGREEMENT...
FOR WEATHER SPECIFICS HAVE FAVORED A BLEND OF THE HRRR AND NAM12
THROUGH THE FIRST HALF OF THE SHORT TERM FOLLOWED BY A MIX OF THE NAM
AND LATEST ECMWF SOLUTIONS.
SENSIBLE WEATHER WILL FEATURE AREAS OF FOG...LOCALLY DENSE...BURNING
OFF EARLY THIS MORNING. THIS WILL BE FOLLOWED BY THE ARRIVAL OF
SHOWERS AND THUNDERSTORMS BY MID AFTERNOON FROM NORTH TO SOUTH AS A
COLD FRONT PRESSES SOUTH INTO THE AREA. PWS WITH THIS CONVECTION WILL
BE MODERATELY HIGH WHILE STORM MOTION STARTS TO SPEED UP AS THE DAY
WEARS ON. THIS SHOULD LIMIT THE RISK FOR FLASH FLOODING WHEN COMPARED
TO THE PAST SEVERAL DAYS. HOWEVER...A LOCALIZED THREAT FOR HEAVY RAIN
WILL REMAIN SHOULD TRAINING DEVELOP IN ANY PARTICULARLY LOCATION.
THE THUNDER IS ANTICIPATED TO FADE FROM THE CONVECTION LATER TONIGHT
AS THE FRONT SINKS SOUTH OF AREA LEAVING JUST A FEW LIGHT SHOWERS
TRAILING BEHIND. FOR SUNDAY...THE NEARBY FRONT MAY CAUSE A SHOWER OR
TWO TO POP UP OVER FAR SOUTHEAST KENTUCKY WHILE THE BOUNDARY SLOWS
IN RESPONSE TO A BUCKLE IN THE MID LEVEL FLOW AND A DEVELOPING WAVE
AT THE SFC ALONG THE GEORGIA COAST. THE WARMTH AND STICKY HUMIDITY
WILL LEAVE THE AREA...AT LEAST FOR A COUPLE OF DAYS...ONCE THE FRONT
MOVES THROUGH MEANING THAT SUNDAY WILL BE A MUCH MORE COMFORTABLE DAY
THAN TODAY AND ALSO PROVIDE A HINT OF THE FALL-LIKE WEATHER THAT
COULD ARRIVE IN EARNEST LATER IN THE WEEK.
FOR TEMPERATURES...DEWPOINTS...AND WINDS...USED THE CONSSHORT FOR
THE FIRST 24 HOURS AND THEN THE SUPERBLEND THROUGH SUNDAY. DID MAKE
SOME MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS TONIGHT. AS
FOR POPS ENDED UP ON THE HIGH SIDE OF MOS GUIDANCE TODAY...COUNTING
ON MOST OF THE AREA MEASURING AS THIS FRONT MOVES THROUGH GIVEN THE
FAIRLY HIGH MOISTURE CONTENT IN PLACE. WAS SIMILAR TO THE GUIDANCE
TONIGHT AND SUNDAY...LIMITING THE CHANCE POPS TO THE FAR SOUTHEAST.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 335 AM EDT SAT SEP 6 2014
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT IN REGARDS TO A
SIGNIFICANT PATTERN CHANGE FOR THE END OF NEXT WEEK...WITH A MAJOR
COOL DOWN IN STORE. HOWEVER...THE MODELS DIFFER IN HOW THEY HANDLE
THE EVOLUTION OF WEATHER SYSTEMS THAT WILL BRING SHOWERS AND STORMS
TO EASTERN KENTUCKY DURING THE UPCOMING WORK WEEK. THE PERIOD WILL
START OUT WARM AND DRY AS HIGH PRESSURE SUNDAY NIGHT THROUGH
TUESDAY. THERE IS A POSSIBILITY OF SCATTERED SHOWERS AND STORMS
FORMING BENEATH THE RIDGE ON MONDAY...AS MOISTURE OFF THE GULF OF
MEXICO GETS DRAWN INTO THE AREA BY A WEAK AREA OF LOW PRESSURE THAT
IS PROGGED TO PASS ACROSS THE TENNESSEE VALLEY. THE ECMWF WAS SLOWER
AND WETTER THAN THE GFS FROM WEDNESDAY ONWARD. BOTH MODELS HAVE A
COLD FRONT MOVING ACROSS THE OHIO AND TENNESSEE VALLEY REGIONS
WEDNESDAY THROUGH FRIDAY...WITH SCATTERED SHOWERS AND STORMS FORMING
IN THE VICINITY OF THE BOUNDARY. WITH UNCERTAINTY BETWEEN THE
MODELS...DECIDED TO USE A BLEND OF THE ECMWF AND GFS MODELS...WITH A
SLIGHT BIAS TOWARD TO NORMALLY MORE RELIABLE ECMWF SOLUTION. THE
BEST CHANCES FOR RAIN WILL COME FROM LATE WEDNESDAY NIGHT THROUGH
THURSDAY EVENING DURING FRONTAL PASSAGE.
TEMPERATURES THE FIRST FEW DAYS OF THE PERIOD LOOK TO BE AT OR
SLIGHT BELOW NORMAL...DUE TO THE INFLUENCE OF NORTHERLY FLOW...CLOUD
COVER...AND PRECIPITATION ASSOCIATED WITH AN AREA OF LOW PRESSURE
THAT IS EXPECTED TO PASS THROUGH THE TENNESSEE VALLEY ON MONDAY.
HIGHS ON MONDAY ARE EXPECTED TO TOP OUT AROUND 80...WITH READINGS
MAXING OUT IN THE LOW TO MID 80S ON TUESDAY AND WEDNESDAY. THE BIG
PATTERN CHANGE LOOKS LIKE IT WILL TAKE PLACE FROM THURSDAY
ONWARD...AS A COOL CANADIAN AIR MASS SETTLES OVER THE REGION BEHIND
A DEPARTING AND VERY POTENT COLD FRONT. HIGHS ON FRIDAY MIGHT ONLY
TOP OUT IN THE LOW TO MID 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 755 AM EDT SAT SEP 6 2014
THE FOG AT THE TAF SITES WILL LIFT AND DISSIPATING BY 1330Z.
BEST CHANCES OF CONVECTION SHOULD HOLD OFF UNTIL AT LEAST 15Z ACROSS
THE OFFICIAL TAF SITES TODAY...AWAITING THE NEARING APPROACH OF THE
COLD FRONT. WITH THE HIGH PROBABILITIES OF CONVECTION ALONG THE
FRONT...WENT WITH PREVAILING TSRA AND WITH THE LOWER...MVFR...
VIS/CIGS STARTING AT 15Z AT THE FARTHEST NW SITE /KSYM/...AND 17Z
AT THE SOUTHERN MOST SITE /KSME/ TO MATCH UP WITH ONGOING LIKELY TO
CATEGORICAL POPS IN THE FORECAST. JUST SOME SCATTERED SHOWERS FOLLOW
LATER THIS EVENING AT THE SITES WITH CIGS EXPECTED TO REMAIN IN THE
MVFR RANGE POST-FRONTAL. WINDS THROUGH THE BULK OF THE PERIOD WILL
BE LIGHT AND VARIABLE BUT SWITCH TO THE NORTH AND NORTHWEST AT 5 TO
10 KTS BEHIND THE FRONT AS IT DROPS SOUTH DURING THE DAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS PADUCAH KY
625 AM CDT Sat Sep 6 2014
.SHORT TERM...(Today through Monday night)
Issued at 258 AM CDT SAT SEP 6 2014
With the first 12 to 18 hours of the short term forecast period,
it becomes quite nebulous to depict the coverage of mainly post
frontal precipitation across the WFO PAH forecast area. All the
3km HRRR guidance pinpoints the more significant storm scale
convection prior to 15z, there is some discontinuity in coverage
of precipitation in the medium scale numerical model guidance.
Utilized a "Superblend" of numerical model guidance to modify and
mitigate various model biases during the first 12-18 hours of
Weather and PoP. The current shortwave moving across Southeast
Kansas should bring the last gasp of convective activity across
the WFO PAH forecast area later this morning/early this afternoon.
Most of the convection early this afternoon should be waning over
parts of West Kentucky.
After this afternoon, dry conditions should dominate through most
of Monday.
.LONG TERM...(Tuesday through Friday)
Issued at 258 AM CDT SAT SEP 6 2014
Model blend for the extended package. A blend of previous ECMWF
deterministic runs coupled with 00z/12z GFS operational runs and
the GEFS 00z run. The 18z GFS was discounted as was the 00z ECMWF
mainly for Thursday night on.
Backed off inherited PoPs for convection Tuesday through Tuesday
night. Best moisture sets up north and west of the region. No
surface focus and little support aloft to warrant much activity.
Have no PoPs in Tuesday, and small chances Tuesday night mainly
north of a Greenville, MO to Owensboro, KY line.
Warm sector much of Wednesday as well. Strong surface low should
reach either WI or the Great Lakes region with a trailing front to
the SW, that will approach our area from the NW by the end of the
day. Have best chance PoPs for convection up toward I-64 tapering
off to 30s in west KY, parts of SEMO. Will probably be a sharper
gradient. Our highest PoPs will be Wednesday night. Model cluster
brings the front through Wednesday night with decent columnar
moisture and mid level support in WSW flow around h5.
Thursday the front should gradually push on through. Will have high
chance PoPs across the south tapering off to slight chances up along
I-64, especially morning, tapering off more in the afternoon. Went
dry Thursday night. Could be some showers close to the AR/TN state
lines, some of which could creep up north into our area. The 00z
ECMWF is a significant outlier in spreading substantial moisture and
QPF back across the region Thursday night. Given its prior 3 runs,
and 4 runs of the GFS suggesting otherwise, threw this latest
depiction out. Will monitor though, in case there`s a signal
suggesting a slight northward adjustment will eventually be needed.
Dry Friday through Friday night with strong high pressure continuing
to build in from the NW. The cool down will be noticeable behind the
front Thursday through Friday. We did not go quite as cool as raw
model output. That means we raised previous highs just a bit. MOS
tend to be climo bias that far out. But given the we should see some
mid Sept. sun, a compromise seems best.
&&
.AVIATION...
Issued at 624 AM CDT SAT SEP 6 2014
Introduced post-frontal LIFR to MVFR stratus deck into the WFO PAH
TAF sites near the beginning of the forecast period, followed by a
gradual rise to MVFR/VFR ceilings throughout the first 12 hours of
the forecast, as drier air moves into the area from the north.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...Smith
LONG TERM...CN
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS PADUCAH KY
259 AM CDT Sat Sep 6 2014
.SHORT TERM...(Today through Monday night)
Issued at 258 AM CDT SAT SEP 6 2014
With the first 12 to 18 hours of the short term forecast period,
it becomes quite nebulous to depict the coverage of mainly post
frontal precipitation across the WFO PAH forecast area. All the
3km HRRR guidance pinpoints the more significant storm scale
convection prior to 15z, there is some discontinuity in coverage
of precipitation in the medium scale numerical model guidance.
Utilized a "Superblend" of numerical model guidance to modify and
mitigate various model biases during the first 12-18 hours of
Weather and PoP. The current shortwave moving across Southeast
Kansas should bring the last gasp of convective activity across
the WFO PAH forecast area later this morning/early this afternoon.
Most of the convection early this afternoon should be waning over
parts of West Kentucky.
After this afternoon, dry conditions should dominate through most
of Monday.
.LONG TERM...(Tuesday through Friday)
Issued at 258 AM CDT SAT SEP 6 2014
Model blend for the extended package. A blend of previous ECMWF
deterministic runs coupled with 00z/12z GFS operational runs and
the GEFS 00z run. The 18z GFS was discounted as was the 00z ECMWF
mainly for Thursday night on.
Backed off inherited PoPs for convection Tuesday through Tuesday
night. Best moisture sets up north and west of the region. No
surface focus and little support aloft to warrant much activity.
Have no PoPs in Tuesday, and small chances Tuesday night mainly
north of a Greenville, MO to Owensboro, KY line.
Warm sector much of Wednesday as well. Strong surface low should
reach either WI or the Great Lakes region with a trailing front to
the SW, that will approach our area from the NW by the end of the
day. Have best chance PoPs for convection up toward I-64 tapering
off to 30s in west KY, parts of SEMO. Will probably be a sharper
gradient. Our highest PoPs will be Wednesday night. Model cluster
brings the front through Wednesday night with decent columnar
moisture and mid level support in WSW flow around h5.
Thursday the front should gradually push on through. Will have high
chance PoPs across the south tapering off to slight chances up along
I-64, especially morning, tapering off more in the afternoon. Went
dry Thursday night. Could be some showers close to the AR/TN state
lines, some of which could creep up north into our area. The 00z
ECMWF is a significant outlier in spreading substantial moisture and
QPF back across the region Thursday night. Given its prior 3 runs,
and 4 runs of the GFS suggesting otherwise, threw this latest
depiction out. Will monitor though, in case there`s a signal
suggesting a slight northward adjustment will eventually be needed.
Dry Friday through Friday night with strong high pressure continuing
to build in from the NW. The cool down will be noticeable behind the
front Thursday through Friday. We did not go quite as cool as raw
model output. That means we raised previous highs just a bit. MOS
tend to be climo bias that far out. But given the we should see some
mid Sept. sun, a compromise seems best.
&&
.AVIATION...
Issued at 541 PM CDT FRI SEP 5 2014
Diurnal storms have really diminished in the last 30 minutes, and
should be all but dissipated by issuance time. Will scatter some
mid clouds, otherwise run with inherited MVFR cigs coming in with
front late tonight. Tmrw shud see winds behind front go northerly
as cigs slowly improve.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...Smith
LONG TERM...CN
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
350 AM EDT SAT SEP 6 2014
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 350 AM EDT SAT SEP 6 2014
07Z SFC ANALYSIS SHOWS AN AREA OF LOW PRESSURE MOVING THROUGH EASTERN
CANADA WITH A TRAILING COLD FRONT RUNNING SOUTHWEST THROUGH THE OHIO
VALLEY AND INTO SOUTHERN MISSOURI. THE REMAINS OF A SQUALL LINE HAS
SETTLED JUST SOUTH OF THE OHIO RIVER...OUT AHEAD OF THE COLD FRONT. A
FEW LINGERING SHOWERS REMAIN WITH THIS AS IT CONTINUES TO FADE OUT
WITH ITS APPROACH TO THE JKL CWA. ON SATELLITE...MID AND HIGH LEVEL
CLOUDS COVER THE OHIO VALLEY NORTH AND WEST OF THIS OUTFLOW BOUNDARY.
HOWEVER...THE CLEARER SKIES TO THE SOUTH HAS ALLOWED AREAS OF FOG TO
DEVELOP THROUGH EAST KENTUCKY WITH LOCALLY DENSE PATCHES IN THE
VALLEYS. HIGH DEWPOINTS IN THE UPPER 60S AND LOWER 70S ARE PROVIDING
A FLOOR TO THE COOLING THIS NIGHT WITH JUST A SMALL RIDGE AND VALLEY
SPLIT EVIDENT WITH READINGS VARYING FROM LOWER 70S IN THE THERMAL
BELT TO THE UPPER 60S IN THE LOW SPOTS. WINDS REMAIN LIGHT TO CALM
THROUGH THE AREA.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS
HEIGHTS FALL OVER THE OHIO VALLEY IN RESPONSE TO A BROAD TROUGH
MOVING THROUGH THE NORTHEAST PORTION OF THE CONTINENT. THE ENERGY
STREAM ASSOCIATED WITH THIS MOVES QUICKLY INTO THE SOUTHERN OHIO
VALLEY TODAY...BUT THEN LINGERS OVERHEAD THROUGH THE WEEKEND WITH A
BIT OF A RESURGENCE LATER SUNDAY. GIVEN THE GOOD MODEL AGREEMENT...
FOR WEATHER SPECIFICS HAVE FAVORED A BLEND OF THE HRRR AND NAM12
THROUGH THE FIRST HALF OF THE SHORT TERM FOLLOWED BY A MIX OF THE NAM
AND LATEST ECMWF SOLUTIONS.
SENSIBLE WEATHER WILL FEATURE AREAS OF FOG...LOCALLY DENSE...BURNING
OFF EARLY THIS MORNING. THIS WILL BE FOLLOWED BY THE ARRIVAL OF
SHOWERS AND THUNDERSTORMS BY MID AFTERNOON FROM NORTH TO SOUTH AS A
COLD FRONT PRESSES SOUTH INTO THE AREA. PWS WITH THIS CONVECTION WILL
BE MODERATELY HIGH WHILE STORM MOTION STARTS TO SPEED UP AS THE DAY
WEARS ON. THIS SHOULD LIMIT THE RISK FOR FLASH FLOODING WHEN COMPARED
TO THE PAST SEVERAL DAYS. HOWEVER...A LOCALIZED THREAT FOR HEAVY RAIN
WILL REMAIN SHOULD TRAINING DEVELOP IN ANY PARTICULARLY LOCATIONS.
THE THUNDER IS ANTICIPATED TO FADE FROM THE CONVECTION LATER TONIGHT
AS THE FRONT SINKS SOUTH OF AREA LEAVING JUST LIGHT SHOWER TRAILING
BEHIND. FOR SUNDAY...THE NEARBY FRONT MAY CAUSE A FEW SHOWERS TO POP
UP OVER FAR SOUTHERN KENTUCKY AS THE BOUNDARY SLOWS IN RESPONSE TO
A BUCKLE IN THE MID LEVEL FLOW AND A DEVELOPING WAVE AT THE SFC ALONG
THE GEORGIA COAST. THE WARMTH AND STICKY HUMIDITY WILL LEAVE THE AREA
AT LEAST FOR A COUPLE OF DAYS ONCE THE FRONT MOVES THROUGH MEANING
THAT SUNDAY WILL BE A MUCH MORE COMFORTABLE DAY THAN TODAY AND
PROVIDE A HINT OF THE FALL-LIKE WEATHER THAT COULD ARRIVE IN EARNEST
LATER IN THE WEEK.
FOR TEMPERATURES...DEWPOINTS...AND WINDS...USED THE CONSSHORT THROUGH
THE FIRST 24 HOURS AND THEN THE SUPERBLEND THROUGH SUNDAY. DID MAKE
SOME MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS TONIGHT. AS
FOR POPS ENDED UP ON THE HIGH SIDE OF MOS GUIDANCE TODAY...COUNTING
ON MOST OF THE AREA MEASURING AS THIS FRONT MOVES THROUGH GIVEN THE
FAIRLY HIGH MOISTURE CONTENT IN PLACE. WAS SIMILAR TO THE GUIDANCE
TONIGHT AND SUNDAY...LIMITING THE CHANCE POPS TO THE FAR SOUTHEAST.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 335 AM EDT SAT SEP 6 2014
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT IN REGARDS TO A
SIGNIFICANT PATTERN CHANGE FOR THE END OF NEXT WEEK...WITH A MAJOR
COOL DOWN IN STORE. HOWEVER...THE MODELS DIFFER IN HOW THEY HANDLE
THE EVOLUTION OF WEATHER SYSTEMS THAT WILL BRING SHOWERS AND STORMS
TO EASTERN KENTUCKY DURING THE UPCOMING WORK WEEK. THE PERIOD WILL
START OUT WARM AND DRY AS HIGH PRESSURE SUNDAY NIGHT THROUGH
TUESDAY. THERE IS A POSSIBILITY OF SCATTERED SHOWERS AND STORMS
FORMING BENEATH THE RIDGE ON MONDAY...AS MOISTURE OFF THE GULF OF
MEXICO GETS DRAWN INTO THE AREA BY A WEAK AREA OF LOW PRESSURE THAT
IS PROGGED TO PASS ACROSS THE TENNESSEE VALLEY. THE ECMWF WAS SLOWER
AND WETTER THAN THE GFS FROM WEDNESDAY ONWARD. BOTH MODELS HAVE A
COLD FRONT MOVING ACROSS THE OHIO AND TENNESSEE VALLEY REGIONS
WEDNESDAY THROUGH FRIDAY...WITH SCATTERED SHOWERS AND STORMS FORMING
IN THE VICINITY OF THE BOUNDARY. WITH UNCERTAINTY BETWEEN THE
MODELS...DECIDED TO USE A BLEND OF THE ECMWF AND GFS MODELS...WITH A
SLIGHT BIAS TOWARD TO NORMALLY MORE RELIABLE ECMWF SOLUTION. THE
BEST CHANCES FOR RAIN WILL COME FROM LATE WEDNESDAY NIGHT THROUGH
THURSDAY EVENING DURING FRONTAL PASSAGE.
TEMPERATURES THE FIRST FEW DAYS OF THE PERIOD LOOK TO BE AT OR
SLIGHT BELOW NORMAL...DUE TO THE INFLUENCE OF NORTHERLY FLOW...CLOUD
COVER...AND PRECIPITATION ASSOCIATED WITH AN AREA OF LOW PRESSURE
THAT IS EXPECTED TO PASS THROUGH THE TENNESSEE VALLEY ON MONDAY.
HIGHS ON MONDAY ARE EXPECTED TO TOP OUT AROUND 80...WITH READINGS
MAXING OUT IN THE LOW TO MID 80S ON TUESDAY AND WEDNESDAY. THE BIG
PATTERN CHANGE LOOKS LIKE IT WILL TAKE PLACE FROM THURSDAY
ONWARD...AS A COOL CANADIAN AIR MASS SETTLES OVER THE REGION BEHIND
A DEPARTING AND VERY POTENT COLD FRONT. HIGHS ON FRIDAY MIGHT ONLY
TOP OUT IN THE LOW TO MID 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 205 AM EDT SAT SEP 6 2014
MAINLY VALLEY FOG IS ANTICIPATED DURING THE REMAINDER OF THE
NIGHT...LIFTING AND DISSIPATING BY 13Z. ATTM...VIS IS EXPECTED TO
FALL INTO THE MVFR RANGE AT THE TAF SITES...PENDING ON THE DEGREE OF
CLEARING...BUT SOME IFR VIS COULD OCCUR. USED A BRIEF TEMPO GROUP FOR
THIS UNCERTAINTY. MOST LIKELY...THE LOWER ELEVATION TAF SITES WILL
EXPERIENCE JUMPS IN AND OUT OF IFR NEAR DAWN. A STRAY SHRA OR TSRA
CANNOT BE RULED OUT AFTER 9Z IN THE FAR NW...BUT HIGHER CHANCES
SHOULD HOLD OFF UNTIL AT LEAST 15Z ACROSS THE OFFICIAL TAF SITES.
HIGH PROBABILITIES OF CONVECTION WILL OCCUR ALONG THE FRONTAL
PASSAGE...SO WENT WITH PREVAILING TSRA AND WITH THE LOWER...MVFR...
VIS AND CIGS STARTING AT 15Z AT THE FARTHEST NW SITE /KSYM/...AND 17Z
AT THE SOUTHERN MOST SITE /KSME/ TO MATCH UP WITH ONGOING LIKELY TO
CATEGORICAL POPS IN THE FORECAST. WINDS THROUGH THE BULK OF THE
PERIOD WILL BE LIGHT AND VARIABLE BUT SWITCH TO THE NORTHWEST AT 5 TO
10 KTS BEHIND THE FRONT AS IT DROPS SOUTH DURING THE DAY...SATURDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
205 AM EDT SAT SEP 6 2014
.UPDATE...
ISSUED AT 130 AM EDT SAT SEP 6 2014
CLEARING IN THE LATE EVENING OVER SOUTHEAST KENTUCKY LED TO A PERIOD
OF RADIATIONAL COOLING FOR MUCH OF THE AREA. HOWEVER...WITH SUCH HIGH
DEWPOINT AIR IN PLACE...TEMPERATURES DID NOT DROP TOO FAR...BUT AREAS
OF FOG DID DEVELOP AND HAVE BECOME LOCALLY DENSE. UPDATED THE GRIDS
TO REFLECT THIS AND ALSO SLOWED THE ARRIVAL OF CONVECTION UNTIL
CLOSER TO DAWN OVER THE NORTHERN PARTS OF THE CWA. ADDITIONALLY...
TWEAKED THE HOURLY T AND TD GRIDS FOR THE LATEST OBS...TRENDS...AND
CONSSHORT DATA. THESE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB
SERVERS AND A FRESHENED SET OF ZONES AND HWO WERE ISSUED.
UPDATE ISSUED AT 1048 PM EDT FRI SEP 5 2014
LATEST TRACKING OF THE LINE OF STORMS TO OUR NW BRINGS THE LINE JUST
TO THE NORTH OF THE CWA BETWEEN 7 AND 8Z THIS MORNING. SO FAR THE
LATEST HRRR SEEMS TO BE FAIRLY WELL ON TRACK WITH THE ONGOING
CONVECTION...AS DOES THE 00Z NAM12. BOTH MODELS POINT AT THE LINE
EXPANDING AS IT NEARS THE OHIO RIVER VALLEY...WITH STORMS DEVELOPING
OUT AHEAD OF THE MAIN LINE. THE HRRR IS A BIT QUICKER IN PULLING
THESE SHOWERS AND THUNDERSTORMS INTO EASTERN KY AS COMPARED TO THE
NAM12...AND SEEMS TO BE FOLLOWING THE CURRENT STORM MOTION BETTER
THAN THE NAM12 AS WELL. THE ECMWF ALSO SUPPORTS THE HRRR SOLUTION...SO
CHOSE TO RELY MORE HEAVILY ON THIS COMBINATION. IF BOTH THE HRRR AND
ECMWF HOLD TRUE...INITIAL ISOLATED CONVECTION WILL SPREAD INTO THE
NORTHERN COUNTIES OF THE CWA BETWEEN 9 AND 12Z...WITH THE MAIN LINE
PASSING THROUGH SOMEWHERE CLOSER TO 18Z. THIS SEEMS TO BE FAIRLY ON
TRACK WITH THE ONGOING FORECAST...SO HAVE MADE NO CHANGES FROM THE
PREVIOUS UPDATE EARLIER THIS EVENING.
THERE IS STILL A FAIRLY GOOD DEW POINT DEPRESSION ACROSS THE WESTERN
AND NORTHERN PORTION OF THE CWA AT THE MOMENT. HOWEVER...A CONTINUED
BREAK IN THE CLOUDS FOR THE NEXT FEW HOURS COULD BE ENOUGH TO PULL
TEMPS DOWN AND ALLOW PATCHY FOG TO DEVELOP. GIVEN THE RAIN SHOWERS
THIS EVENING OVER THE EASTERN CWA...DEW POINT DEPRESSIONS ARE MUCH
LOWER HERE...SO EXPECT SOME PATCHY FOG TO PERHAPS BEGIN DEVELOPING A
LITTLE SOONER IN THESE LOCATIONS. THIS MIGHT END UP BEING AN HOUR OR
TWO SOONER THAN WHEN THE FOG IS MENTIONED IN THE GRIDS.
OTHERWISE...THE ONLY OTHER UPDATE MADE WAS TO LOAD IN THE LATEST
OBSERVATIONAL DATA FOR TEMPS...WINDS...AND DEW POINTS TO MAKE SURE
CURRENT CONDITIONS WERE REFLECTED IN THE NEAR TERM FORECAST. THIS
UPDATE RESULTED IN VERY LITTLE CHANGE FROM THE ONGOING FORECAST.
UPDATE ISSUED AT 757 PM EDT FRI SEP 5 2014
GIVEN THE CURRENT RADAR TRENDS...AND LATEST HIRES MODEL
DATA...DECIDED TO PUSH BACK THE ONSET OF SHOWERS AND THUNDERSTORMS BY
SEVERAL HOURS. ORIGINAL FORECAST HAD SLIGHT CHANCES MOVING INTO THE
FAR NW COUNTIES WITHIN THE NEXT 1 TO 2 HOURS. UNFORTUNATELY...THE
LINE OF SHOWERS AND THUNDERSTORMS IS STILL OVER ILLINOIS AND NORTHERN
INDIANA...AND IS NOT EXPECTED TO REACH KY FOR ANOTHER SEVERAL HOURS.
EXPECT THAT WE WILL REMAIN DRY IN EASTERN KY THROUGH MUCH OF THE
NIGHT...WITH SLIGHT CHANCES MOVING IN LATE TONIGHT IN THE NW...AND
SLOWLY SPREADING SE NEAR DAWN. THIS ALSO SEEMED TO MATCH UP BETTER
WITH SOME OF OUR SURROUNDING OFFICES. WOULD NOT BE SURPRISED THAT
POPS MAY HAVE TO BE PUSHED BACK EVEN FURTHER LATER THIS
EVENING/OVERNIGHT...UNLESS SOMETHING DEVELOPS OUT AHEAD OF THE MAIN
LINE...BUT WILL WAIT TO SEE HOW THE CURRENT FORECAST PANS OUT FOR THE
NEXT SEVERAL HOURS.
STILL EXPECT PATCHY TO AREAS OF FOG TO DEVELOP AHEAD OF THE RAIN
OVERNIGHT...SO LEFT FOG FORECAST UNTOUCHED FOR NOW. LOADED IN THE
LATEST OBSERVATIONAL GUIDANCE FOR TEMPS...DEW POINTS...AND WINDS TO
MAKE SURE THE NEAR TERM FORECAST WAS WELL ON TRACK WITH CURRENT
CONDITIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 415 PM EDT FRI SEP 5 2014
AS OF THE MID TO LATE AFTERNOON HOURS...AN UPPER LEVEL RIDGE OF HIGH
PRESSURE REMAINS ACROSS THE SOUTHEASTERN CONUS WITH AN UPPER LEVEL
TROUGH OVER THE NORTHERN AND CENTRAL PLAINS. ONE SHORTWAVE WAS
WORKING ACROSS THE CENTRAL PLAINS...WHILE ANOTHER WAS WORKING EAST
NEAR THE US/CANADIAN BORDER. THE SOUTHERN SHORTWAVE WILL WORK EAST
AND INTO THE MID MS AND LOWER OH VALLEY REGION LATE TONIGHT AND INTO
TOMORROW...THEN SLOWLY EAST ACROSS THE COMMONWEALTH THROUGH THE END
OF THE PERIOD. THE NORTHERN SHORTWAVE IS PROJECTED TO WORK INTO THE
NORTHEASTERN US DURING THAT TIME. THE PATTERN WILL RESULT IN TROUGH
ACROSS THE NORTHEASTERN US AND OH VALLEY REGION BY THE END OF THE
PERIOD. A COLD FRONT IN ADVANCE OF THIS TROUGH WILL WORK INTO THE OH
VALLEY TONIGHT AND THEN ACROSS THE AREA THROUGH EARLY ON SATURDAY
AFTERNOON. HIGH PRESSURE WILL BEGIN TO BUILD INTO THE ARE BEHIND THE
FRONT ON SATURDAY EVENING AND SATURDAY NIGHT AND START TO USHER IN A
COOLER AND LESS HUMID AIRMASS.
CONVECTION HAS GENERALLY WANED OVER THE PAST COUPLE OF HOURS AS MUCH
OF THE REGION HAS BEEN WORKED OVER. HOWEVER...ISOLATED CONVECTION
LINGERS ACROSS THE BIG SANDY REGION AND THE VA BORDER COUNTIES. WE
OPTED TO HOLD ONTO SOME SLIGHT CHANCE TO CHANCE POPS FOR THE FIRST
HOUR OR TWO. A RELATIVE LULL IN THE CONVECTION CHANCES WILL OCCUR
FROM THE EVENING INTO THE OVERNIGHT HOURS WITH THE LOSS OF DAYTIME
HEATING AND IN ADVANCE OF THE SHORTWAVE TROUGH AND COLD FRONT. HOWEVER...
SOME STRAY CONVECTION CANNOT BE COMPLETELY RULED OUT OVERNIGHT.
ALSO...DEPENDING ON THE DEGREE OF CLEARING PATCHY FOG SHOULD ALSO
DEVELOP...ESPECIALLY IN LOCATIONS THAT RECEIVED RAIN TODAY. THE
AIRMASS REMAINS VERY MOIST AND WINDS ARE EXPECTED TO BE ON THE LIGHT
SIDE.
ON SATURDAY...THE CHANCES FOR CONVECTION WILL INCREASE ACROSS THE
AREA AS THE COLD FRONT DROPS SOUTHEAST INTO THE REGION DURING THE
MORNING. WITH SOME HEATING OF THE MOIST AIRMASS...SHOWERS AND
THUNDERSTORMS NEAR THE BOUNDARY AND IN ADVANCE OF THE SHORTWAVE
SHOULD BECOME RATHER NUMEROUS. CHANCES WILL BE THE HIGHEST IN THE
NORTHWEST PART OF THE AREA FROM THE LATE MORNING INTO EARLY AFTERNOON
AND THEN DURING THE AFTERNOON TO EARLY EVENING ACROSS THE REMAINDER
OF THE REGION. THERE WILL BE PLENTY OF MOISTURE STILL IN PLACE FOR
THE SHORTWAVE AND FRONT TO WORK WITH AND STORM MOTIONS WILL NOT BE
ALL THAT HIGH. LOCALLY HEAVY RAIN WILL BE A THREAT FROM THESE. IF
THERE IS AN AREA... POSSIBLY THE EASTERN OR SOUTHEASTERN PART OF THE
AREA THAT GETS QUITE A BIT OF SUNSHINE IN THE MORNING...THEN A STRONG
STORM OR TWO WITH STRONG WIND GUSTS WOULD ALSO BE POSSIBLE. THIS HAS
BEEN HIGHLIGHTED IN THE HWO.
CLOUDS AND THE THREAT FOR SHOWERS OR SOME LIGHT RAIN WILL LINGER INTO
SATURDAY NIGHT...ESPECIALLY ACROSS THE SOUTHEAST. THUNDERSTORM
CHANCES WILL ALSO DIMINISH BY LATE IN THE EVENING AS THE ATMOSPHERE
STABILIZES. PLENTY OF LOW LEVEL MOISTURE AND LOW CLOUDS AND POSSIBLY
STRATUS BUILD DOWN FOG WILL LINGER BEHIND THE BOUNDARY INTO SATURDAY
NIGHT...AND CLOUD COVER SHOULD BE MOSTLY CLOUDY TO CLOUDY. LOW
TEMPERATURES ON SATURDAY NIGHT WILL BE COLDER THAN RECENT
NIGHTS...BUT RATHER CLOSE TO NORMAL.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 300 PM EDT FRI SEP 5 2014
THERE IS GOOD MODEL AGREEMENT ON THE OVERALL PATTERN CHANGE IN STORE
FOR LATE NEXT WEEK...WITH MUCH COOLER AIR INVADING THE AREA AS COOL
CANADIAN SURFACE HIGH PRESSURE INVADES THE PLAINS IN THE WAKE OF A
COLD FRONT. HOWEVER...THE DAY TO DAY DETAILS AND TIMING OF EVENTS IS
VERY UNCERTAIN...AND THERE CONTINUES TO BE LOW CONFIDENCE IN THE
SPECIFICS OF THE FORECAST FOR NEXT WEEK. THE STANDARD MODEL BLEND LOAD
HELPS TO TAKE INTO ACCOUNT THE VARIOUS MODEL DIFFERENCES...AND
FOLLOWING THIS IDEA LEADS TO A CONTINUATION OF SHOWER AND
THUNDERSTORM CHANCES FOR EVERY DAY NEXT WEEK. AFTER THE INITIAL COOL
DOWN LATE THIS WEEKEND...TEMPERATURES WILL REBOUND AGAIN. THE
BIG TEMPERATURE CHANGES BEING ADVERTISED WILL HAVE TO WAIT UNTIL THE
END OF THIS FORECAST PERIOD AND BEYOND. IN ANY CASE A MORE FALL LIKE
PATTERN WITH BELOW NORMAL TEMPERATURES IS IN STORE JUST BEYOND THE
RANGE OF THIS FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 205 AM EDT SAT SEP 6 2014
MAINLY VALLEY FOG IS ANTICIPATED DURING THE REMAINDER OF THE
NIGHT...LIFTING AND DISSIPATING BY 13Z. ATTM...VIS IS EXPECTED TO
FALL INTO THE MVFR RANGE AT THE TAF SITES...PENDING ON THE DEGREE OF
CLEARING...BUT SOME IFR VIS COULD OCCUR. USED A BRIEF TEMPO GROUP FOR
THIS UNCERTAINTY. MOST LIKELY...THE LOWER ELEVATION TAF SITES WILL
EXPERIENCE JUMPS IN AND OUT OF IFR NEAR DAWN. A STRAY SHRA OR TSRA
CANNOT BE RULED OUT AFTER 9Z IN THE FAR NW...BUT HIGHER CHANCES
SHOULD HOLD OFF UNTIL AT LEAST 15Z ACROSS THE OFFICIAL TAF SITES.
HIGH PROBABILITIES OF CONVECTION WILL OCCUR ALONG THE FRONTAL
PASSAGE...SO WENT WITH PREVAILING TSRA AND WITH THE LOWER...MVFR...
VIS AND CIGS STARTING AT 15Z AT THE FARTHEST NW SITE /KSYM/...AND 17Z
AT THE SOUTHERN MOST SITE /KSME/ TO MATCH UP WITH ONGOING LIKELY TO
CATEGORICAL POPS IN THE FORECAST. WINDS THROUGH THE BULK OF THE
PERIOD WILL BE LIGHT AND VARIABLE BUT SWITCH TO THE NORTHWEST AT 5 TO
10 KTS BEHIND THE FRONT AS IT DROPS SOUTH DURING THE DAY...SATURDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...JP
LONG TERM...SBH
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS GRAY ME
652 PM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH OFFSHORE THIS EVENING. HIGH PRESSURE WILL
BUILD IN FROM THE WEST SUNDAY AND WILL SHIFT INTO THE MARITIMES ON
MONDAY. HIGH PRESSURE WILL HOLD OFF THE COAST THROUGH TUESDAY. A
WARM FRONT WILL LIFT NORTH THROUGH THE REGION ON WEDNESDAY. A COLD
FRONT WILL APPROACH FROM THE WEST ON THURSDAY AND WILL SLOWLY
CROSS THE AREA ON FRIDAY.
&&
.NEAR TERM /TONIGHT/...
7PM UPDATE...
HAVE UPDATED TO DROP THE SEVERE THUNDERSTORM WATCH AS THE FRONT
AND THUNDERSTORMS ALONG IT HAS MADE IT TO THE COAST. SEVERE THREAT
FOR TODAY IS OVER. RAIN CHANCES ARE ALSO GREATLY REDUCED. COOLER
AND DRIER AIR IS MOVING IN SHARPLY BEHIND THIS FRONT. NO OTHER
CHANGES MADE TO THE FORECAST AT THIS TIME.
PREVIOUS DISCUSSION...
DEEP MOISTURE AND INCREASED INSTABILITY WITH HIGH CAPE AND
PRECIPITABLE WATER VALUES WILL COMBINE WITH AN APPROACHING FRONT
TO TRIGGER MORE SCATTERED SHOWERS AND THUNDERSTORMS INTO THIS
EVENING. A FEW OF THESE STORMS MAY CONTAIN DAMAGING WIND GUSTS AND
LOCALLY VERY HEAVY RAINFALL INTO THIS EVENING.
LATEST HRRR MODEL RUN...WHICH HAS HANDLED THIS EVENT RELATIVELY
WELL...CONTINUES TO SHOW THE CONVECTION ALONG THE IMMEDIATE COAST
TIL AROUND 23Z.
AFTER THE COLD FRONTAL PASSAGE...SKIES WILL BEGIN TO
CLEAR AND CONDITIONS WILL BECOME MORE COMFORTABLE AS DEW POINT
VALUES FALL. THERE WILL BE SOME INLAND FOG DEVELOPING LATE AT
NIGHT OVER THE USUAL SUSPECT LOCATIONS INCLUDING THE CONNECTICUT
RIVER VALLEY.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
ALL MODELS IN AGREEMENT DEPICTING HIGH PRESSURE WILL BEGIN TO
BUILD INTO THE REGION SUNDAY WITH CLEARING SKIES OVER THE COAST
EARLY IN THE MORNING. NORTHWEST...OFFSHORE WINDS WILL ALLOW FOR
MILD TEMPERATURES ALONG THE COAST.
WITH COLD AIR ADVECTION CONTINUING SUNDAY NIGHT...EXPECT A FEW
READINGS IN THE UPPER 30S IN THE MOUNTAINS. THERE MAY BE SOME
SCATTERED FROST IN THE MOUNTAINS...IN THE COLDEST VALLEYS.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL CREST OVER THE REGION EARLY MONDAY BEFORE
SHIFTING EAST INTO THE MARITIMES. EXPECT MOSTLY SUNNY SKIES BUT
TEMPERATURES WILL AVERAGE OUT BELOW NORMAL WITH HIGHS ONLY IN THE
60S.
MOSTLY CLEAR MONDAY NIGHT WITH LOWS IN THE MID 40S TO LOWER 50S.
MOSTLY CLEAR AND QUIET WEATHER CONTINUES ON TUESDAY AS HIGH
PRESSURE REMAINS ANCHORED TO THE EAST. ONCE AGAIN TEMPERATURES
WILL AVERAGE OUT BELOW NORMAL WITH HIGHS IN THE 60S TO NEAR 70.
WARM FRONT SETTING UP TO THE NORTHWEST OF THE FORECAST AREA ON
WEDNESDAY WILL BRING A FEW CLOUDS TO NORTHERN ZONES BUT EXPECT
ANY ASSOCIATED PRECIPITATION TO REMAIN WELL WEST OF THE FORECAST
AREA. REMAINDER OF THE REGION WILL SEE A MOSTLY SUNNY DAY WITH
MODERATING TEMPERATURES. EXPECT MUCH OF THE REGION TO TOP OUT IN
THE LOWER TO MID 70S.
WARM FRONT WILL STALL ACROSS NORTHERN ZONES WEDNESDAY NIGHT BEFORE
LIFTING NORTHWARD ON THURSDAY. MAY SEE SOME SHOWERS IN NORTHERN
ZONES AFTER MIDNIGHT AS STRONGER OVER-RUNNING SHIFTS IN FROM THE
WEST. REMAINDER OF THE FORECAST AREA WILL SEE INCREASING CLOUDS.
OVER-RUNNING PRECIPITATION WILL OVER-SPREAD THE REGION ON
THURSDAY. AN OCCLUDED FRONT PUSHING IN FROM THE WEST MAY BRING
SOME LATE DAY CONVECTION TO WESTERN ZONES AND MAY CONTINUE INTO
THURSDAY NIGHT AS THE FRONT SLOWLY PUSHES EASTWARD.
FRONT WILL STALL ACROSS THE REGION BY FRIDAY MORNING AND WILL BE
THE FOCUS FOR MORE RAIN AS A STRONG SHORTWAVE SWINGS IN FROM THE
WEST. THIS WILL FINALLY SWEEP THE FRONT OFFSHORE BY LATE IN THE DAY.
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT FOR THE WEEKEND WITH
ANOTHER SHOT OF UNSEASONABLY COOL WEATHER.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...LOCAL IFR OR LIFR CONDITIONS IN CONVECTION THIS
EVENING WITH LOCALLY STRONG WIND GUSTS AND IN PATCHY FOG LATE.
LONG TERM...VFR MONDAY THROUGH WEDNESDAY. MVFR/IFR
CEILINGS/VISIBILITY THURSDAY.
&&
.MARINE...
SHORT TERM...SCA FOR WINDS/SEAS THROUGH THIS EVENING FOR THE OUTER
COASTAL WATERS.
LONG TERM...NO PROBLEMS NOTED.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT SUNDAY FOR ANZ150-152-154.
&&
$$
NEAR TERM UPDATE...KIMBLE
AREA FORECAST DISCUSSION
NWS GRAY ME
513 PM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH OFFSHORE THIS EVENING. HIGH PRESSURE WILL
BUILD IN FROM THE WEST SUNDAY AND WILL SHIFT INTO THE MARITIMES ON
MONDAY. HIGH PRESSURE WILL HOLD OFF THE COAST THROUGH TUESDAY. A
WARM FRONT WILL LIFT NORTH THROUGH THE REGION ON WEDNESDAY. A COLD
FRONT WILL APPROACH FROM THE WEST ON THURSDAY AND WILL SLOWLY
CROSS THE AREA ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
*** SEVERE THUNDERSTORM WATCH BOX OUR TIL 9 PM FOR ALL AREAS
EXCEPT THE NORTHERN MOUNTAINS ***
DEEP MOISTURE AND INCREASED INSTABILITY WITH HIGH CAPE AND
PRECIPITABLE WATER VALUES WILL COMBINE WITH AN APPROACHING FRONT
TO TRIGGER MORE SCATTERED SHOWERS AND THUNDERSTORMS INTO THIS
EVENING. A FEW OF THESE STORMS MAY CONTAIN DAMAGING WIND GUSTS AND
LOCALLY VERY HEAVY RAINFALL INTO THIS EVENING.
LATEST HRRR MODEL RUN...WHICH HAS HANDLED THIS EVENT RELATIVELY
WELL...CONTINUES TO SHOW THE CONVECTION ALONG THE IMMEDIATE COAST
TIL AROUND 23Z.
AFTER THE COLD FRONTAL PASSAGE...SKIES WILL BEGIN TO
CLEAR AND CONDITIONS WILL BECOME MORE COMFORTABLE AS DEW POINT
VALUES FALL. THERE WILL BE SOME INLAND FOG DEVELOPING LATE AT
NIGHT OVER THE USUAL SUSPECT LOCATIONS INCLUDING THE CT RIVER
VALLEY.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
ALL MODELS IN AGREEMENT DEPICTING HIGH PRESSURE WILL BEGIN TO
BUILD INTO THE REGION SUNDAY WITH CLEARING SKIES OVER THE COAST
EARLY IN THE MORNING. NORTHWEST...OFFSHORE WINDS WILL ALLOW FOR
MILD TEMPS ALONG THE COAST.
WITH COLD AIR ADVECTION CONTINUING SUNDAY NIGHT...EXPECT A FEW
READINGS IN THE UPPER 30S IN THE MOUNTAINS. THERE MAY BE SOME
SCATTERED FROST IN THE MOUNTAINS...IN THE COLDEST VALLEYS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WILL CREST OVER THE REGION EARLY MONDAY BEFORE SHIFTING EAST
INTO THE MARITIMES. EXPECT MOSTLY SUNNY SKIES BUT TEMPS WILL
AVERAGE OUT BELOW NORMAL WITH HIGHS ONLY IN THE 60S.
MOSTLY CLEAR MONDAY NIGHT WITH LOWS IN THE MID 40S TO LOWER 50S. MOSTLY
CLEAR AND QUIET WEATHER CONTINUES ON TUESDAY AS HIGH PRESSURE
REMAINS ANCHORED TO THE EAST. ONCE AGAIN TEMPS WILL AVERAGE OUT
BELOW NORMAL WITH HIGHS IN THE 60S TO NEAR 70.
WARM FRONT SETTING UP TO THE NORTHWEST OF THE FORECAST AREA ON WEDNESDAY
WILL BRING A FEW CLOUDS TO NORTHERN ZONES BUT EXPECT ANY
ASSOCIATED PRECIP TO REMAIN WELL WEST OF THE FORECAST AREA.
REMAINDER OF THE REGION WILL SEE A MOSTLY SUNNY DAY WITH
MODERATING TEMPS. EXPECT MUCH OF THE REGION TO TOP OUT IN THE
LOWER TO MID 70S.
WARM FRONT WILL STALL ACROSS NORTHERN ZONES WEDNESDAY NIGHT BEFORE
LIFTING NORTHWARD ON THURSDAY. MAY SEE SOME SHOWERS IN NORTHERN
ZONES AFTER MIDNIGHT AS STRONGER OVER-RUNNING SHIFTS IN FROM THE
WEST. REMAINDER OF THE FORECAST AREA WILL SEE INCREASING CLOUDS.
OVER-RUNNING PRECIP WILL OVER-SPREAD THE REGION ON THURSDAY. AN
OCCLUDED FRONT PUSHING IN FROM THE WEST MAY BRING SOME LATE DAY
CONVECTION TO WESTERN ZONES AND MAY CONTINUE INTO THURSDAY NIGHT
AS THE FRONT SLOWLY PUSHES EASTWARD.
FRONT WILL STALL ACROSS THE REGION BY FRIDAY MORNING AND WILL BE
THE FOCUS FOR MORE RAIN AS A STRONG SHORTWAVE SWINGS IN FROM THE
WEST. THIS WILL FINALLY SWEEP THE FRONT OFFSHORE BY LATE IN THE DAY.
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT FOR THE WEEKEND WITH
ANOTHER SHOT OF UNSEASONABLY COOL WEATHER.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
SHORT TERM...LOCAL IFR OR LIFR CONDITIONS IN CONVECTION THIS
EVENING WITH LOCALLY STRONG WIND GUSTS AND IN PATCHY FOG LATE.
LONG TERM...VFR MONDAY THROUGH WEDNESDAY. MVFR/IFR CEILINGS/VSBY
THURSDAY.
&&
.MARINE...
SHORT TERM...SCA FOR WINDS/SEAS THROUGH THIS EVENING FOR THE OUTER
COASTAL WATERS.
LONG TERM...NO PROBLEMS NOTED.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT SUNDAY FOR ANZ150-152-154.
&&
$$
JC
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
430 PM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH OFFSHORE THIS EVENING. HIGH PRESSURE WILL
BUILD IN FROM THE WEST SUNDAY AND WILL SHIFT INTO THE MARITIMES ON
MONDAY. HIGH PRESSURE WILL HOLD OFF THE COAST THROUGH TUESDAY. A
WARM FRONT WILL LIFT NORTH THROUGH THE REGION ON WEDNESDAY. A COLD
FRONT WILL APPROACH FROM THE WEST ON THURSDAY AND WILL SLOWLY
CROSS THE AREA ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
*** SEVERE THUNDERSTORM WATCH BOX OUR TIL 9 PM FOR ALL AREAS
EXCEPT THE NORTHERN MOUNTAINS ***
DEEP MOISTURE AND INCREASED INSTABILITY WITH HIGH CAPE AND
PRECIPITABLE WATER VALUES WILL COMBINE WITH AN APPROACHING FRONT
TO TRIGGER MORE SCATTERED SHOWERS AND THUNDERSTORMS INTO THIS
EVENING. A FEW OF THESE STORMS MAY CONTAIN DAMAGING WIND GUSTS AND
LOCALLY VERY HEAVY RAINFALL INTO THIS EVENING.
LATEST HRRR MODEL RUN...WHICH HAS HANDLED THIS EVENT RELATIVELY
WELL...CONTINUES TO SHOW THE CONVECTION ALONG THE IMMEDIATE COAST
TIL AROUND 23Z.
AFTER THE COLD FRONTAL PASSAGE...SKIES WILL BEGIN TO
CLEAR AND CONDITIONS WILL BECOME MORE COMFORTABLE AS DEW POINT
VALUES FALL. THERE WILL BE SOME INLAND FOG DEVELOPING LATE AT
NIGHT OVER THE USUAL SUSPECT LOCATIONS INCLUDING THE CT RIVER
VALLEY.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
ALL MODELS IN AGREEMENT DEPICTING HIGH PRESSURE WILL BEGIN TO
BUILD INTO THE REGION SUNDAY WITH CLEARING SKIES OVER THE COAST
EARLY IN THE MORNING. NORTHWEST...OFFSHORE WINDS WILL ALLOW FOR
MILD TEMPS ALONG THE COAST.
WITH COLD AIR ADVECTION CONTINUING SUNDAY NIGHT...EXPECT A FEW
READINGS IN THE UPPER 30S IN THE MOUNTAINS. THERE MAY BE SOME
SCATTERED FROST IN THE MOUNTAINS...IN THE COLDEST VALLEYS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WILL CREST OVER THE REGION EARLY MONDAY BEFORE SHIFTING EAST
INTO THE MARITIMES. EXPECT MOSTLY SUNNY SKIES BUT TEMPS WILL
AVERAGE OUT BELOW NORMAL WITH HIGHS ONLY IN THE 60S.
MOSTLY CLEAR MONDAY NIGHT WITH LOWS IN THE MID 40S TO LOWER 50S. MOSTLY
CLEAR AND QUIET WEATHER CONTINUES ON TUESDAY AS HIGH PRESSURE
REMAINS ANCHORED TO THE EAST. ONCE AGAIN TEMPS WILL AVERAGE OUT
BELOW NORMAL WITH HIGHS IN THE 60S TO NEAR 70.
WARM FRONT SETTING UP TO THE NORTHWEST OF THE FORECAST AREA ON WEDNESDAY
WILL BRING A FEW CLOUDS TO NORTHERN ZONES BUT EXPECT ANY
ASSOCIATED PRECIP TO REMAIN WELL WEST OF THE FORECAST AREA.
REMAINDER OF THE REGION WILL SEE A MOSTLY SUNNY DAY WITH
MODERATING TEMPS. EXPECT MUCH OF THE REGION TO TOP OUT IN THE
LOWER TO MID 70S.
WARM FRONT WILL STALL ACROSS NORTHERN ZONES WEDNESDAY NIGHT BEFORE
LIFTING NORTHWARD ON THURSDAY. MAY SEE SOME SHOWERS IN NORTHERN
ZONES AFTER MIDNIGHT AS STRONGER OVER-RUNNING SHIFTS IN FROM THE
WEST. REMAINDER OF THE FORECAST AREA WILL SEE INCREASING CLOUDS.
OVER-RUNNING PRECIP WILL OVER-SPREAD THE REGION ON THURSDAY. AN
OCCLUDED FRONT PUSHING IN FROM THE WEST MAY BRING SOME LATE DAY
CONVECTION TO WESTERN ZONES AND MAY CONTINUE INTO THURSDAY NIGHT
AS THE FRONT SLOWLY PUSHES EASTWARD.
FRONT WILL STALL ACROSS THE REGION BY FRIDAY MORNING AND WILL BE
THE FOCUS FOR MORE RAIN AS A STRONG SHORTWAVE SWINGS IN FROM THE
WEST. THIS WILL FINALLY SWEEP THE FRONT OFFSHORE BY LATE IN THE DAY.
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT FOR THE WEEKEND WITH
ANOTHER SHOT OF UNSEASONABLY COOL WEATHER.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
SHORT TERM...LOCAL IFR OR LIFR CONDITIONS IN CONVECTION THIS
EVENING WITH LOCALLY STRONG WIND GUSTS AND IN PATCHY FOG LATE.
LONG TERM...VFR MONDAY THROUGH WEDNESDAY. MVFR/IFR CEILINGS/VSBY
THURSDAY.
&&
.MARINE...
SHORT TERM...SCA FOR WINDS/SEAS THROUGH THIS EVENING FOR THE OUTER
COASTAL WATERS.
LONG TERM...NO PROBLEMS NOTED.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT SUNDAY FOR ANZ150-152-154.
&&
$$
JC
AREA FORECAST DISCUSSION
NWS GRAY ME
131 PM EDT SAT SEP 6 2014
.SYNOPSIS...
THE RETURN FLOW AROUND HIGH PRESSURE HAS INTRODUCED A VERY WARM
AND HUMID AIR MASS TO THE REGION. A COLD FRONT WILL CROSS THE
REGION TODAY ACCOMPANIED BY SHOWERS AND THUNDERSTORMS. SOME
THUNDERSTORMS MAY PRODUCE STRONG GUSTY WINDS...FREQUENT
LIGHTNING...AND TORRENTIAL DOWNPOURS WITH LOCALIZED FLOODING. HIGH
PRESSURE AND DRY AIR FOLLOWS THE FRONT SUNDAY THROUGH TUESDAY.
THE NEXT DISTURBANCE WITH UNSETTLED WEATHER SHOULD ARRIVE BY THE
MIDDLE OF NEXT WEEK. THE UNSETTLED WEATHER IS EXPECTED TO CONTINUE
THROUGH THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...
***SEVERE THUNDERSTORM WATCH #497 NOW IN EFFECT TIL 9 PM***
HAVE UPDATED THE GRIDS BASED ON CURRENT CONDITIONS AS WELL AS
LATEST MESOSCALE MODEL DATA. LATEST HRRR CONTINUES TO SHOW THE
HIGHEST DEW POINTS AND THE GREATEST CHANCE FOR SEVERE WEATHER TO
BE OVER SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE. WE CURRENTLY
REMAIN IN A SLIGHT RISK FOR SEVERE WEATHER TODAY.
WILL CONTINUE THE ENHANCED WORDING...WITH THE PRIMARY THREAT BEING
DAMAGING WIND GUSTS IN SEVERE STORMS. AN ISOLATED TORNADO IS
POSSIBLE AS WELL...WITH STRONG WIND FIELDS AND SIGNIFICANT SHEAR.
HAVE ADJUSTED DEW POINT AND CLOUD GRIDS AS WELL BASED ON CURRENT
SATELLITE IMAGERY...SURFACE OBSERVATIONS AND SOUNDING ANALYSIS.
KEY WILL BE IF DRY AIR MIXES DOWN FROM ABOVE AND LOWERS OUR DEW
POINTS OR NOT. MOST LIKELY AREA TO HAVE DEW POINTS NEAR 70 DEGREES
WILL BE SOUTHERN NEW HAMPSHIRE AND YORK COUNTY IN MAINE.
PREV DISC...
HAVE UPDATED THE FORECAST SLIGHTLY THIS MORNING TO
INCORPORATE LATEST TRENDS IN OBSERVATIONAL DATA. SHOULD SEE PLENTY
OF SUN THIS MORNING WHICH SHOULD LEAD TO QUICK INSOLATIONAL
HEATING. FORECAST FOR THUNDERSTORMS REMAINS THE SAME FOR THIS
AFTERNOON.
PREVIOUSLY...
A WARM AND HUMID AIR MASS HAS OVERSPREAD THE REGION AS OF EARLY
THIS SATURDAY MORNING...AS EVIDENCED BY TEMPERATURES STILL IN THE
70S WITH DEWPOINTS WELL INTO THE 60S AS OF 3 AM. A COLD FRONT IS
EXPECTED TO CROSS THE AREA TODAY AND THIS SHOULD AID IN THE
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS.
THE MAIN CONCERN REVOLVES AROUND STORM COVERAGE...TIMING...AND
SEVERITY. AS A SHORT WAVE TROUGH APPROACHES FROM THE NW AND
CONTINUES TO INDUCE HEIGHT FALLS...A COLD FRONT AND ASSOCIATED SFC
CONVERGENCE SHOULD INITIATE THUNDERSTORMS ACROSS THE INTERIOR
AROUND MIDDAY. STRONG SFC HEATING IS EXPECTED OUT AHEAD OF THE
THUNDERSTORM ACTIVITY WITH HIGHS IN THE MID TO UPPER 80S PROGGED ON
THE COASTAL PLAIN. A FEW LOCATIONS MAY EVEN TOUCH 90 FROM INTERIOR
ROCKINGHAM COUNTY NORTHWARD INTO INTERIOR YORK AND CUMBERLAND
COUNTIES. THIS COMBINED WITH DEWPOINT VALUES IN THE UPPER 60S TO
AROUND 70 SHOULD RESULT IN MODERATE SBCAPE BY EARLY AFTERNOON WITH
VALUES IN EXCESS OF 2000 J/KG. THEREFORE...PLENTY OF INSTABILITY
IS EXPECTED TO BE PRESENT TO SUPPORT SVR STORMS.
HOWEVER...
THERE ARE SOME NEGATIVES...SUCH AS GRADUALLY WEAKENING MID LEVEL
LAPSE RATES AS THE DAY PROGRESSES. ALSO...THE BEST DEEP LAYER
SHEAR AND UPPER SUPPORT IS EXPECTED TO LAG BEHIND THE COLD FRONT.
IN ADDITION...GOOD MIXING TO AROUND 850 MB IS EXPECTED TODAY. THIS
WILL PROBABLY RESULT IN FALLING DEWPOINTS THIS AFTERNOON IN SOME
AREAS...AND THIS WOULD EAT AWAY AT CAPE VALUES. ANOTHER ISSUE MAY
BE THAT A PREFRONTAL TROF THAT IS EXPECTED TO DEVELOP ON THE
COASTAL PLAIN EARLY THIS AFTERNOON COULD MOVE OFFSHORE TOO EARLY.
THIS WOULD LOWER DEWPOINTS ACROSS THE AREA AND WEAKEN SFC
CONVERGENCE.
NEVERTHELESS...WE EXPECT AT LEAST A COUPLE OF SEVERE STORMS IN
THE FORM OF ORGANIZED MULTICELL CLUSTERS AND LINE SEGMENTS WHICH
MAY EVENTUALLY FORM A MORE SOLID LINE OF STORMS AS THEY APPROACH
THE COAST. THE MAIN THREAT LOOK TO BE DAMAGING WINDS. TORRENTIAL
DOWNPOURS ARE EXPECTED IN STORMS WITH THE ATTENDANT LOW RISK OF
ISOLD FLASH FLOODING IN AREAS WHERE STORMS TRAIN IN THE HIGH PWAT
AIR MASS. A NON-ZERO TORNADO THREAT MAY EXIST TODAY IN THE
VICINITY OF MESOSCALE BOUNDARIES IF BRIEF SUPERCELL STRUCTURES CAN
DEVELOP. AREAS OF LOCALLY BACKED WINDS TODAY WOULD BE SUPPORTIVE
OF FAIRLY SIZABLE LOW LEVEL HODOGRAPHS GIVEN THE RELATIVELY STRONG
SWLY WINDS EXPECTED IN THE 0-2 KM LAYER. THIS IS CONDITIONAL APON
FAVRORABLE MOISTURE PROFILES THIS AFTERNOON...IE...IF WE DON/T MIX
OUT THE RICH LOW LEVEL MOISTURE DUE TO MIXING OR A DEPARTING
PREFRONTAL TROF TOO EARLY.
CAPPED POPS AT LIKELY TODAY BECAUSE I/M NOT SO SURE THAT EVERYONE
WILL SEE A STORM. THE MODELS SEEMED TO HAVE BACKED OFF ON
COVERAGE A LITTLE BIT...PROBABLY DUE TO THE NEGATIVE FACTORS
OUTLINED ABOVE. HIGHEST POPS HAVE BEEN PLACED BETWEEN 19Z AND
23Z.
SFC WINDS LOOK TO BECOME GUSTY TODAY OUTSIDE OF ANY
CONVECTION...POSSIBLY TO AROUND 25 MPH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
SHOWERS AND STORMS WILL SWEEP OFFSHORE EARLY THIS EVENING.
CLEARING SHOULD OCCUR TONIGHT ASIDE FROM LEFTOVER STRATUS AND FOG.
SUNDAY SHOULD BE A REALLY NICE DAY...WARM AND MUCH DRIER.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
MODELS ARE IN A LITTLE BETTER AGREEMENT THIS MORNING FOR THE LONG
TERM PERIOD. HIGH PRESSURE WILL DOMINATE THE WEATHER FOR SUNDAY
NIGHT THROUGH TUESDAY. TEMPERATURES SUNDAY NIGHT WILL DIP TO
RATHER CHILLY LEVELS WITH SOME OF THE COLDER MOUNTAIN VALLEYS
POSSIBLY SEEING SOME FROST. A WEAK SYSTEM WILL PASS SOUTH OF THE
REGION TUESDAY AND TUESDAY NIGHT AND SPREAD CLOUDS INTO SOUTHERN
AREAS WITH ONLY A SLIGHT CHANCE OF A SHOWER. FAIR WEATHER IS
EXPECTED WEDNESDAY WITH THE WEAK SURFACE RIDGE REMAINING ACROSS
THE REGION. LOW PRESSURE MOVING THROUGH SOUTHEASTERN CANADA
THURSDAY AND THURSDAY NIGHT WILL DRAG A COLD FRONT ACROSS THE
REGION WITH SHOWERS/TSTMS LIKELY DURING THE DAY. MODELS START TO
DIVERGE A BIT WITH THIS SYSTEM...ADDING UNCERTAINTY TO THE
FORECAST. THE FRONT SHOULD BE OFF THE COAST BY FRIDAY MORNING. A
SECOND FRONT WILL APPROACH THE AREA SATURDAY WITH AN INCREASING
CHANCE OF SHOWERS.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
SHORT TERM...SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY...MAINLY
THIS AFTERNOON. THIS WOULD ALLOW FOR LOCAL IFR CONDITIONS. BETTER
CONDITIONS ARE FORECAST LATER TONIGHT ALTHOUGH SOME STRATUS AND
FOG MAY DEVELOP IN RIVER VALLEYS AND ALONG THE COAST...ESPECIALLY
THIS EVENING BEFORE DRIER AIR ARRIVES. WALL TO WALL VFR EXPECTED
SUNDAY.
LONG TERM...MAINLY VFR CONDITIONS WITH IFR CONDITIONS POSSIBLE IN
MORNING VALLEY FOG.
&&
.MARINE...
SHORT TERM...SCA FOR THE OUTER WATERS THROUGH THIS EVENING FOR
MARGINAL SMALL CRAFT CONDITIONS. A FEW 25 KT GUSTS MAY OCCUR IN
THE BAYS AS WELL...BUT CONFIDENCE IS LOW. THUNDERSTORMS WITH GUSTY
WINDS ARE EXPECTED TO POSE A HAZARD LATE THIS AFTERNOON.
LONG TERM...NO FLAGS THROUGH TUESDAY. SEAS MAY REACH SCA CRITERIA
LATE TUE NIGHT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT SUNDAY FOR ANZ150-152-154.
&&
$$
JC
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1246 PM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL CONTINUE MOVING SOUTHEAST ACROSS THE EAST CENTRAL
AND DOWNEAST PORTIONS OF THE REGION THIS AFTERNOON. COOLER HIGH
PRESSURE WILL BUILD IN BEHIND THE FRONT SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1242 PM UPDATE: POPS AND SKY GRIDS LOOK REASONABLE FROM THE LAST
UPDATE...SO NO CHGS FOR THESE ELEMENTS THIS UPDATE. FCST HRLY TEMPS
AND FCST AFTN HI TEMPS NEEDED TOP BE ADJUSTED BASED ON TRENDS
FROM NOON OBSVD TEMPS.
ORGNL DISC: SEVERE WEATHER STILL LOOKS TO BE A GOOD THREAT MAINLY
FROM THE HOULTON-MILLINOCKET REGION DOWN THROUGH THE CENTRAL
HIGHLANDS AND INTERIOR DOWNEAST.
THE LATEST SURFACE ANALYSIS AT 06Z SHOWED THE COLD FRONT MOVING
INTO QUEBEC W/AN AREA OF SHOWERS AND ISOLD TSTMS MOVING ACROSS NW
MAINE TOWARD NE MAINE. LATEST MESO ANALYSIS SHOWED THE BEST
INSTABILITY RESIDING IN THIS REGION AS SHOWN BY THE LIFTED INDEX
OF -2 TO -4 RUNNING FROM QUEBEC THROUGH NW MAINE. FURTHER E,
ATMOSPHERE IS MORE STABLE ATTM. THE HRRR 3KM AND THE NAM12 WERE
DOING WELL W/PLACEMENT AND INSTABILITY. A LARGE LINE OF LIGHTNING
STRIKES HAD EXTENDED FROM QUEBEC DOWN ACROSS NYS AND PA
BUT HAVE SINCE DISSIPATED. THIS IS EXPECTED TO CHANGE LATER THIS
MORNING INTO THE AFTERNOON THE FRONT CONTINUE TO PUSH E AND THE
AIRMASS DESTABILIZES. THE LATEST RUNS OF THE NAM AND GFS CONTINUE
TO SHOW THE HIGHEST THREAT FOR POSSIBLY SEVERE TSTMS W/EHI
RUNNING FROM 1 TO 2 AND SB/MU CAPES OF 1200-2000 JOULES AND 0-6KM
SHEAR OF 35-40 KTS. ANOTHER FACTOR TO CONSIDER WILL BE THE
DIRECTIONAL SHEAR THROUGH 850MBS AND LCLS MAKING THEIR DECENT FROM
5K FT DOWN TO 2500 FT. IN ADDITION TO ALL THIS WILL BE VERY HIGH
PWATS OF 1.7+ INCHES AND SWEAT INDEX OF 300+. ALL THIS WOULD
SUGGEST THE POTENTIAL FOR DAMAGING WINDS AND VERY HEAVY RAINFALL.
SOME ROTATION COULD BE SEEN IN THE STRONGER STORMS GIVEN THE
TURNING IN THE LLVLS AND THE LOWER LCLS. KEPT THE ENHANCED WORDING
FOR GUSTY WINDS AND HEAVY RAINFALL. THE WORDING MIGHT NEED TO BE
BOOSTED TO INCLUDE DAMAGING WINDS IF THINGS HOLD W/THE UPDATE
LATER THIS MORNING. TEMPERATURES WILL FALL BACK ACROSS NORTHERN
MAINE AFTER 1 PM AS THE FRONT SLIDE THROUGH WHILE THE CENTRAL
HIGHLANDS AND DOWNEAST WILL HAVE TIME TO HEAT UP W/AFTERNOON
TEMPERATURES HITTING IN THE LOWER 80S. SPC HAS KEPT THE SLIGHT
RISK FOR SEVERE WEATHER FOR OUR REGION IN PLACE FOR TODAY.
THE COLD FRONT IS FORECAST TO SLIDE INTO THE COASTAL WATERS THIS
EVENING W/PARTIAL CLEARING TAKING PLACE AND A DRAMATIC COOL DOWN.
WE ARE TALKING 10-15 DEGREES COOLER THAN WHAT WE HAVE SEEN THAT
LAST FEW MORNINGS. SOME OF THE SITES BACK TO THE W AND NW COULD
DROP BACK INTO THE UPPER 30S BY EARLY MONDAY MORNING.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
AT THE START OF THE NEAR TERM PERIOD. A COLD FRONT WILL BE
EXTENDED ALONG THE COAST OF MAINE. HIGHER PRESSURE WILL BEGIN TO
BUILD INTO THE AREA. COOLER DRIER AIR WILL MOVE INTO THE AREA WITH
THE HIGH. DAY TIME TEMPS SUNDAY IN THE MID 60S AND LOWER 60S
MONDAY. OVERNIGHT LOWS IN THE LOWER 40S. THE HIGH PRESSURE RIDGE
WILL DOMINATE THE WEATHER THROUGH THE NEAR TERM PERIOD OF THE
FORECAST.
LOADED A BLEND OF THE GFS/NAM/GEM/ECMWF FOR HRLY
TEMPS/DP...WND...POP... AND SKY. NAWAVE 4 FOR SEAS IN THE COASTAL
WATERS. ADDED 15 PERCENT TO WINDS FOR GUSTS OVER LAND...25 PERCENT
OVER COASTAL WATERS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A HIGH PRESSURE RIDGE WILL BE IN PLACE OVER THE AREA AT THE START
OF THE LONG TERM. A LOW PRESSURE SYSTEM MOVING UP THE EAST COAST
AT THE START OF THE PERIOD THE GFS PLACES IT ALONG THE GULF STREAM
EAST OF NJ...THE ECMWF ALONG THE COAST OF VA. AND THE GEM PLACES
IT EAST OF CAPE COD...SOUTH OF SW NOVA SCOTIA. BY WED MRNG THE GFS
MOVES THE LOW NORTH TO JUST SOUTH OF CAPE COD...WITH THE PRECIP
SHIELD EXTENDING INTO DOWNEAST MAINE...THE ECMWF MOVES THE LOW TO
DELMARVA...KEEPS THE PCPN SHIELD SOUTH OF CAPE COD. THE GEM MOVES
THE LOW TO A POSITION SOUTH OF CENTRAL NOVA SCOTIA WELL EAST OF
OUR AREA. A NEW LOW OVER THE CENTRAL MIDWEST WITH A COLD FRONT
THAT EXTENDS FROM NORTHERN QUEBEC SW TO THE CENTRAL GREAT LAKES
REGION. THE LOW WILL MOVE EAST AND BY THUR MRNG THE GFS MOVE IT TO
THE ERN GREAT LAKES REGION...WITH ITS WARM FRONT EXTENDING INTO
NRN MAINE. THE ECMWF IS A BIT SLOWER WITH THE FORWARD MVMNT OF
THIS LOW...MOVING IT TO LAKE HURON. BY THURS EVNG...THE ECMWF
CATCHES UP A BIT. THE GFS MOVES THE LOW TO SRN QUEBEC/WRN MAINE.
THE ECMWF MOVES THE LOW TO SW QUEBEC. FROM THURS EVNG THROUGH THE
END OF THE PERIOD. THE GFS AND ECMWF ARE ABOUT ONE PERIOD OUT OF
FAZE WITH THE GFS BEING THE FASTER OF THE TWO MODELS. UNSETTLED
WEATHER WILL PERSIST FROM THURS EVNG THROUGH THE END OF THE PERIOD
AS AN UPPER LOW SLOWLY FILLS OVER WEST CENTRAL QUEBEC SE OF JAMES
BAY.
LOADED THE SUPERBLEND FOR THE EXTENDED PERIOD OF THE FORECAST.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: IFR SETTING UP ACROSS KBHB AND POSSIBLY KBGR THIS
MORNING WHILE THE NORTHERN TERMINALS WILL SEE VFR THIS MORNING
GOING TO MVFR. MVFR CONDITIONS FOR ALL TERMINALS INTO THE
AFTERNOON. VFR EXPECTED ACROSS THE NORTHERN TERMINALS TONIGHT
WHILE KBGR AND KBHB COULD SEE A BRIEF PERIOD OF IFR BEFORE
CLEARING LATER TONIGHT AS THE FRONT CLEARS THE AREA.
SHORT TERM: A FEW STRAY SHOWERS FOR BGR AND BHB EARLY IN THE
PERIOD...OTHERWISE VFR CONDITIONS ALL SITES.
&&
.MARINE...
NEAR TERM: 1015 AM ...MAX WIND GUSTS WERE REDUCED TO 20 KT FOR THE
REMAINDER OF THE DAY...DUE TO VERY STABLE SFC-500M LAPSE RATES.
OTHERWISE...CURRENT SCA OVR THE OUTER MZS REMAIN IN PLACE.
ORGNL DISC...CONDITIONS ATTM BELOW SCA LEVELS BOTH IN THE WINDS
AND SEAS W/15 KTS AND 4 TO 5 FT. SEAS WILL CONT AT SCA LEVELS THRU
THE AFTERNOON WINDS DROP OFF BEHIND THE FRONT TO LESS THAN 15 KTS
AND SEAS WILL COME DOWN AS THE WIND GOES OFFSHORE.
SHORT TERM: WINDS AND SEAS BELOW SCA CRITERIA THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ050-
051.
&&
$$
NEAR TERM...VJN
SHORT TERM...NORTON
LONG TERM...NORTON
AVIATION...VJN/NORTON
MARINE...VJN/NORTON
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1020 AM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL REACH NORTHERN MAINE THIS MORNING THEN MOVE
ACROSS THE DOWNEAST REGION LATE THIS AFTERNOON. COOLER HIGH
PRESSURE WILL BUILD IN BEHIND THE FRONT SUNDAY INTO MONDAY.&&
.NEAR TERM /THROUGH TONIGHT/...
1015 AM UPDATE: WE INCREASED POPS TO BETTER MATCH FCST QPF WITH
XPCTD SHWRS AND TSTMS ACROSS THE AREA FOR THE REST OF TDY. WE ALSO
TRIED TO MATCH THE TMG OF STRONGER TSTMS WITH THE CURRENT PSN OF
THE COLD FRONT WHICH IS NEARLY AT KCAR ATTM. THIS MEANS THAT THE
POTENTIAL OF ANY STRONG STORMS ACROSS THE FAR N HAS DIMINISHED
WITH THIS PTN ALREADY BEHIND THE COLD FRONT. OTHERWISE...FCST
HRLY CLD CVR...TEMPS AND FCST HI TEMPS WERE MODIFIED BASED ON
LATEST OBSVD TRENDS...WITH TEMPS JUST AHEAD OF THE COLD FRONT
ACROSS NE PTNS OF ME ALREADY EXCEEDING PRIOR FCST HI TEMPS.
TEMPS OVR THE NE...HOWEVER...WILL LIKELY FALL SHORTLY ONCE THE
FRONT CROSSES THE REGION.
ORGNL DISC: SEVERE WEATHER STILL LOOKS TO BE A GOOD THREAT MAINLY
FROM THE HOULTON-MILLINOCKET REGION DOWN THROUGH THE CENTRAL
HIGHLANDS AND INTERIOR DOWNEAST.
THE LATEST SURFACE ANALYSIS AT 06Z SHOWED THE COLD FRONT MOVING
INTO QUEBEC W/AN AREA OF SHOWERS AND ISOLD TSTMS MOVING ACROSS NW
MAINE TOWARD NE MAINE. LATEST MESO ANALYSIS SHOWED THE BEST
INSTABILITY RESIDING IN THIS REGION AS SHOWN BY THE LIFTED INDEX
OF -2 TO -4 RUNNING FROM QUEBEC THROUGH NW MAINE. FURTHER E,
ATMOSPHERE IS MORE STABLE ATTM. THE HRRR 3KM AND THE NAM12 WERE
DOING WELL W/PLACEMENT AND INSTABILITY. A LARGE LINE OF LIGHTNING
STRIKES HAD EXTENDED FROM QUEBEC DOWN ACROSS NYS AND PA
BUT HAVE SINCE DISSIPATED. THIS IS EXPECTED TO CHANGE LATER THIS
MORNING INTO THE AFTERNOON THE FRONT CONTINUE TO PUSH E AND THE
AIRMASS DESTABILIZES. THE LATEST RUNS OF THE NAM AND GFS CONTINUE
TO SHOW THE HIGHEST THREAT FOR POSSIBLY SEVERE TSTMS W/EHI
RUNNING FROM 1 TO 2 AND SB/MU CAPES OF 1200-2000 JOULES AND 0-6KM
SHEAR OF 35-40 KTS. ANOTHER FACTOR TO CONSIDER WILL BE THE
DIRECTIONAL SHEAR THROUGH 850MBS AND LCLS MAKING THEIR DECENT FROM
5K FT DOWN TO 2500 FT. IN ADDITION TO ALL THIS WILL BE VERY HIGH
PWATS OF 1.7+ INCHES AND SWEAT INDEX OF 300+. ALL THIS WOULD
SUGGEST THE POTENTIAL FOR DAMAGING WINDS AND VERY HEAVY RAINFALL.
SOME ROTATION COULD BE SEEN IN THE STRONGER STORMS GIVEN THE
TURNING IN THE LLVLS AND THE LOWER LCLS. KEPT THE ENHANCED WORDING
FOR GUSTY WINDS AND HEAVY RAINFALL. THE WORDING MIGHT NEED TO BE
BOOSTED TO INCLUDE DAMAGING WINDS IF THINGS HOLD W/THE UPDATE
LATER THIS MORNING. TEMPERATURES WILL FALL BACK ACROSS NORTHERN
MAINE AFTER 1 PM AS THE FRONT SLIDE THROUGH WHILE THE CENTRAL
HIGHLANDS AND DOWNEAST WILL HAVE TIME TO HEAT UP W/AFTERNOON
TEMPERATURES HITTING IN THE LOWER 80S. SPC HAS KEPT THE SLIGHT
RISK FOR SEVERE WEATHER FOR OUR REGION IN PLACE FOR TODAY.
THE COLD FRONT IS FORECAST TO SLIDE INTO THE COASTAL WATERS THIS
EVENING W/PARTIAL CLEARING TAKING PLACE AND A DRAMATIC COOL DOWN.
WE ARE TALKING 10-15 DEGREES COOLER THAN WHAT WE HAVE SEEN THAT
LAST FEW MORNINGS. SOME OF THE SITES BACK TO THE W AND NW COULD
DROP BACK INTO THE UPPER 30S BY EARLY MONDAY MORNING.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
AT THE START OF THE NEAR TERM PERIOD. A COLD FRONT WILL BE
EXTENDED ALONG THE COAST OF MAINE. HIGHER PRESSURE WILL BEGIN TO
BUILD INTO THE AREA. COOLER DRIER AIR WILL MOVE INTO THE AREA WITH
THE HIGH. DAY TIME TEMPS SUNDAY IN THE MID 60S AND LOWER 60S
MONDAY. OVERNIGHT LOWS IN THE LOWER 40S. THE HIGH PRESSURE RIDGE
WILL DOMINATE THE WEATHER THROUGH THE NEAR TERM PERIOD OF THE
FORECAST.
LOADED A BLEND OF THE GFS/NAM/GEM/ECMWF FOR HRLY
TEMPS/DP...WND...POP... AND SKY. NAWAVE 4 FOR SEAS IN THE COASTAL
WATERS. ADDED 15 PERCENT TO WINDS FOR GUSTS OVER LAND...25 PERCENT
OVER COASTAL WATERS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A HIGH PRESSURE RIDGE WILL BE IN PLACE OVER THE AREA AT THE START
OF THE LONG TERM. A LOW PRESSURE SYSTEM MOVING UP THE EAST COAST
AT THE START OF THE PERIOD THE GFS PLACES IT ALONG THE GULF STREAM
EAST OF NJ...THE ECMWF ALONG THE COAST OF VA. AND THE GEM PLACES
IT EAST OF CAPE COD...SOUTH OF SW NOVA SCOTIA. BY WED MRNG THE GFS
MOVES THE LOW NORTH TO JUST SOUTH OF CAPE COD...WITH THE PRECIP
SHIELD EXTENDING INTO DOWNEAST MAINE...THE ECMWF MOVES THE LOW TO
DELMARVA...KEEPS THE PCPN SHIELD SOUTH OF CAPE COD. THE GEM MOVES
THE LOW TO A POSITION SOUTH OF CENTRAL NOVA SCOTIA WELL EAST OF
OUR AREA. A NEW LOW OVER THE CENTRAL MIDWEST WITH A COLD FRONT
THAT EXTENDS FROM NORTHERN QUEBEC SW TO THE CENTRAL GREAT LAKES
REGION. THE LOW WILL MOVE EAST AND BY THUR MRNG THE GFS MOVE IT TO
THE ERN GREAT LAKES REGION...WITH ITS WARM FRONT EXTENDING INTO
NRN MAINE. THE ECMWF IS A BIT SLOWER WITH THE FORWARD MVMNT OF
THIS LOW...MOVING IT TO LAKE HURON. BY THURS EVNG...THE ECMWF
CATCHES UP A BIT. THE GFS MOVES THE LOW TO SRN QUEBEC/WRN MAINE.
THE ECMWF MOVES THE LOW TO SW QUEBEC. FROM THURS EVNG THROUGH THE
END OF THE PERIOD. THE GFS AND ECMWF ARE ABOUT ONE PERIOD OUT OF
FAZE WITH THE GFS BEING THE FASTER OF THE TWO MODELS. UNSETTLED
WEATHER WILL PERSIST FROM THURS EVNG THROUGH THE END OF THE PERIOD
AS AN UPPER LOW SLOWLY FILLS OVER WEST CENTRAL QUEBEC SE OF JAMES
BAY.
LOADED THE SUPERBLEND FOR THE EXTENDED PERIOD OF THE FORECAST.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: IFR SETTING UP ACROSS KBHB AND POSSIBLY KBGR THIS
MORNING WHILE THE NORTHERN TERMINALS WILL SEE VFR THIS MORNING
GOING TO MVFR. MVFR CONDITIONS FOR ALL TERMINALS INTO THE
AFTERNOON. VFR EXPECTED ACROSS THE NORTHERN TERMINALS TONIGHT
WHILE KBGR AND KBHB COULD SEE A BRIEF PERIOD OF IFR BEFORE
CLEARING LATER TONIGHT AS THE FRONT CLEARS THE AREA.
SHORT TERM: A FEW STRAY SHOWERS FOR BGR AND BHB EARLY IN THE
PERIOD...OTHERWISE VFR CONDITIONS ALL SITES.
&&
.MARINE...
NEAR TERM: 1015 AM ...MAX WIND GUSTS WERE REDUCED TO 20 KT FOR THE
REMAINDER OF THE DAY...DUE TO VERY STABLE SFC-500M LAPSE RATES.
OTHERWISE...CURRENT SCA OVR THE OUTER MZS REMAIN IN PLACE.
ORGNL DISC...CONDITIONS ATTM BELOW SCA LEVELS BOTH IN THE WINDS
AND SEAS W/15 KTS AND 4 TO 5 FT. SEAS WILL CONT AT SCA LEVELS THRU
THE AFTERNOON WINDS DROP OFF BEHIND THE FRONT TO LESS THAN 15 KTS
AND SEAS WILL COME DOWN AS THE WIND GOES OFFSHORE.
SHORT TERM: WINDS AND SEAS BELOW SCA CRITERIA THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ050-
051.
&&
$$
NEAR TERM...VJN
SHORT TERM...NORTON
LONG TERM...NORTON
AVIATION...VJN/NORTON
MARINE...VJN/NORTON
AREA FORECAST DISCUSSION
NWS GRAY ME
943 AM EDT SAT SEP 6 2014
.SYNOPSIS...
THE RETURN FLOW AROUND HIGH PRESSURE HAS INTRODUCED A VERY WARM
AND HUMID AIR MASS TO THE REGION. A COLD FRONT WILL CROSS THE
REGION TODAY ACCOMPANIED BY SHOWERS AND THUNDERSTORMS. SOME
THUNDERSTORMS MAY PRODUCE STRONG GUSTY WINDS...FREQUENT
LIGHTNING...AND TORRENTIAL DOWNPOURS WITH LOCALIZED FLOODING. HIGH
PRESSURE AND DRY AIR FOLLOWS THE FRONT SUNDAY THROUGH TUESDAY.
THE NEXT DISTURBANCE WITH UNSETTLED WEATHER SHOULD ARRIVE BY THE
MIDDLE OF NEXT WEEK. THE UNSETTLED WEATHER IS EXPECTED TO CONTINUE
THROUGH THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...
HAVE UPDATED THE GRIDS BASED ON CURRENT CONDITIONS AS WELL AS
LATEST MESOSCALE MODEL DATA. LATEST HRRR CONTINUES TO SHOW THE
HIGHEST DEW POINTS AND THE GREATEST CHANCE FOR SEVERE WEATHER TO
BE OVER SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE. WE CURRENTLY
REMAIN IN A SLIGHT RISK FOR SEVERE WEATHER TODAY.
WILL CONTINUE THE ENHANCED WORDING...WITH THE PRIMARY THREAT BEING
DAMAGING WIND GUSTS IN SEVERE STORMS. AN ISOLATED TORNADO IS
POSSIBLE AS WELL...WITH STRONG WIND FIELDS AND SIGNIFICANT SHEAR.
HAVE ADJUSTED DEW POINT AND CLOUD GRIDS AS WELL BASED ON CURRENT
SATELLITE IMAGERY...SURFACE OBSERVATIONS AND SOUNDING ANALYSIS.
KEY WILL BE IF DRY AIR MIXES DOWN FROM ABOVE AND LOWERS OUR DEW
POINTS OR NOT. MOST LIKELY AREA TO HAVE DEW POINTS NEAR 70 DEGREES
WILL BE SOUTHERN NEW HAMPSHIRE AND YORK COUNTY IN MAINE.
PREV DISC...
HAVE UPDATED THE FORECAST SLIGHTLY THIS MORNING TO
INCORPORATE LATEST TRENDS IN OBSERVATIONAL DATA. SHOULD SEE PLENTY
OF SUN THIS MORNING WHICH SHOULD LEAD TO QUICK INSOLATIONAL
HEATING. FORECAST FOR THUNDERSTORMS REMAINS THE SAME FOR THIS
AFTERNOON.
PREVIOUSLY...
A WARM AND HUMID AIR MASS HAS OVERSPREAD THE REGION AS OF EARLY
THIS SATURDAY MORNING...AS EVIDENCED BY TEMPERATURES STILL IN THE
70S WITH DEWPOINTS WELL INTO THE 60S AS OF 3 AM. A COLD FRONT IS
EXPECTED TO CROSS THE AREA TODAY AND THIS SHOULD AID IN THE
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS.
THE MAIN CONCERN REVOLVES AROUND STORM COVERAGE...TIMING...AND
SEVERITY. AS A SHORT WAVE TROUGH APPROACHES FROM THE NW AND
CONTINUES TO INDUCE HEIGHT FALLS...A COLD FRONT AND ASSOCIATED SFC
CONVERGENCE SHOULD INITIATE THUNDERSTORMS ACROSS THE INTERIOR
AROUND MIDDAY. STRONG SFC HEATING IS EXPECTED OUT AHEAD OF THE
THUNDERSTORM ACTIVITY WITH HIGHS IN THE MID TO UPPER 80S PROGGED ON
THE COASTAL PLAIN. A FEW LOCATIONS MAY EVEN TOUCH 90 FROM INTERIOR
ROCKINGHAM COUNTY NORTHWARD INTO INTERIOR YORK AND CUMBERLAND
COUNTIES. THIS COMBINED WITH DEWPOINT VALUES IN THE UPPER 60S TO
AROUND 70 SHOULD RESULT IN MODERATE SBCAPE BY EARLY AFTERNOON WITH
VALUES IN EXCESS OF 2000 J/KG. THEREFORE...PLENTY OF INSTABILITY
IS EXPECTED TO BE PRESENT TO SUPPORT SVR STORMS.
HOWEVER...
THERE ARE SOME NEGATIVES...SUCH AS GRADUALLY WEAKENING MID LEVEL
LAPSE RATES AS THE DAY PROGRESSES. ALSO...THE BEST DEEP LAYER
SHEAR AND UPPER SUPPORT IS EXPECTED TO LAG BEHIND THE COLD FRONT.
IN ADDITION...GOOD MIXING TO AROUND 850 MB IS EXPECTED TODAY. THIS
WILL PROBABLY RESULT IN FALLING DEWPOINTS THIS AFTERNOON IN SOME
AREAS...AND THIS WOULD EAT AWAY AT CAPE VALUES. ANOTHER ISSUE MAY
BE THAT A PREFRONTAL TROF THAT IS EXPECTED TO DEVELOP ON THE
COASTAL PLAIN EARLY THIS AFTERNOON COULD MOVE OFFSHORE TOO EARLY.
THIS WOULD LOWER DEWPOINTS ACROSS THE AREA AND WEAKEN SFC
CONVERGENCE.
NEVERTHELESS...WE EXPECT AT LEAST A COUPLE OF SEVERE STORMS IN
THE FORM OF ORGANIZED MULTICELL CLUSTERS AND LINE SEGMENTS WHICH
MAY EVENTUALLY FORM A MORE SOLID LINE OF STORMS AS THEY APPROACH
THE COAST. THE MAIN THREAT LOOK TO BE DAMAGING WINDS. TORRENTIAL
DOWNPOURS ARE EXPECTED IN STORMS WITH THE ATTENDANT LOW RISK OF
ISOLD FLASH FLOODING IN AREAS WHERE STORMS TRAIN IN THE HIGH PWAT
AIR MASS. A NON-ZERO TORNADO THREAT MAY EXIST TODAY IN THE
VICINITY OF MESOSCALE BOUNDARIES IF BRIEF SUPERCELL STRUCTURES CAN
DEVELOP. AREAS OF LOCALLY BACKED WINDS TODAY WOULD BE SUPPORTIVE
OF FAIRLY SIZABLE LOW LEVEL HODOGRAPHS GIVEN THE RELATIVELY STRONG
SWLY WINDS EXPECTED IN THE 0-2 KM LAYER. THIS IS CONDITIONAL APON
FAVRORABLE MOISTURE PROFILES THIS AFTERNOON...IE...IF WE DON/T MIX
OUT THE RICH LOW LEVEL MOISTURE DUE TO MIXING OR A DEPARTING
PREFRONTAL TROF TOO EARLY.
CAPPED POPS AT LIKELY TODAY BECAUSE I/M NOT SO SURE THAT EVERYONE
WILL SEE A STORM. THE MODELS SEEMED TO HAVE BACKED OFF ON
COVERAGE A LITTLE BIT...PROBABLY DUE TO THE NEGATIVE FACTORS
OUTLINED ABOVE. HIGHEST POPS HAVE BEEN PLACED BETWEEN 19Z AND
23Z.
SFC WINDS LOOK TO BECOME GUSTY TODAY OUTSIDE OF ANY
CONVECTION...POSSIBLY TO AROUND 25 MPH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
SHOWERS AND STORMS WILL SWEEP OFFSHORE EARLY THIS EVENING.
CLEARING SHOULD OCCUR TONIGHT ASIDE FROM LEFTOVER STRATUS AND FOG.
SUNDAY SHOULD BE A REALLY NICE DAY...WARM AND MUCH DRIER.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
MODELS ARE IN A LITTLE BETTER AGREEMENT THIS MORNING FOR THE LONG
TERM PERIOD. HIGH PRESSURE WILL DOMINATE THE WEATHER FOR SUNDAY
NIGHT THROUGH TUESDAY. TEMPERATURES SUNDAY NIGHT WILL DIP TO
RATHER CHILLY LEVELS WITH SOME OF THE COLDER MOUNTAIN VALLEYS
POSSIBLY SEEING SOME FROST. A WEAK SYSTEM WILL PASS SOUTH OF THE
REGION TUESDAY AND TUESDAY NIGHT AND SPREAD CLOUDS INTO SOUTHERN
AREAS WITH ONLY A SLIGHT CHANCE OF A SHOWER. FAIR WEATHER IS
EXPECTED WEDNESDAY WITH THE WEAK SURFACE RIDGE REMAINING ACROSS
THE REGION. LOW PRESSURE MOVING THROUGH SOUTHEASTERN CANADA
THURSDAY AND THURSDAY NIGHT WILL DRAG A COLD FRONT ACROSS THE
REGION WITH SHOWERS/TSTMS LIKELY DURING THE DAY. MODELS START TO
DIVERGE A BIT WITH THIS SYSTEM...ADDING UNCERTAINTY TO THE
FORECAST. THE FRONT SHOULD BE OFF THE COAST BY FRIDAY MORNING. A
SECOND FRONT WILL APPROACH THE AREA SATURDAY WITH AN INCREASING
CHANCE OF SHOWERS.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY...MAINLY
THIS AFTERNOON. THIS WOULD ALLOW FOR LOCAL IFR CONDITIONS. BETTER
CONDITIONS ARE FORECAST LATER TONIGHT ALTHOUGH SOME STRATUS AND
FOG MAY DEVELOP IN RIVER VALLEYS AND ALONG THE COAST...ESPECIALLY
THIS EVENING BEFORE DRIER AIR ARRIVES. WALL TO WALL VFR EXPECTED
SUNDAY.
LONG TERM...MAINLY VFR CONDITIONS WITH IFR CONDITIONS POSSIBLE IN
MORNING VALLEY FOG.
&&
.MARINE...
SHORT TERM...SCA FOR THE OUTER WATERS THROUGH THIS EVENING FOR
MARGINAL SMALL CRAFT CONDITIONS. A FEW 25 KT GUSTS MAY OCCUR IN
THE BAYS AS WELL...BUT CONFIDENCE IS LOW. THUNDERSTORMS WITH GUSTY
WINDS ARE EXPECTED TO POSE A HAZARD LATE THIS AFTERNOON.
LONG TERM...NO FLAGS THROUGH TUESDAY. SEAS MAY REACH SCA CRITERIA
LATE TUE NIGHT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT SUNDAY FOR ANZ150-152-154.
&&
$$
JC
AREA FORECAST DISCUSSION
NWS CARIBOU ME
632 AM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL REACH NORTHERN MAINE THIS MORNING THEN MOVE
ACROSS THE DOWNEAST REGION LATE THIS AFTERNOON. COOLER HIGH
PRESSURE WILL BUILD IN BEHIND THE FRONT SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
630 AM UPDATE...ADJUSTED THE TIMING FOR SHOWERS AND STORMS BACK BY
ABOUT 2 HOURS BASED ON THE LATEST RADAR AND SATELLITE TRENDS. THE
BEST INSTABILITY STILL RESIDE BACK ACROSS QUEBEC AND ACROSS THE
CROWN OF MAINE PER LATEST LIFTED INDEX(-1 TO -3). KEPT THE MENTION
OF FOG IN THE FORECAST FOR A FEW MORE HOURS. INSTABILITY AXIS
STARTING TO SET UP ACROSS SW MAINE NOSING TOWARD INTERIOR DOWNEAST.
BANGOR TO BAR HARBOR LOOKS TO BE PRETTY STABLE DUE TO STRATUS AND
FOG WHICH SHOULD LIFT AND BURN OFF AFTER 12Z.
SEVERE WEATHER STILL LOOKS TO BE A GOOD THREAT MAINLY FROM THE
HOULTON-MILLINOCKET REGION DOWN THROUGH THE CENTRAL HIGHLANDS AND
INTERIOR DOWNEAST.
THE LATEST SURFACE ANALYSIS AT 06Z SHOWED THE COLD FRONT MOVING
INTO QUEBEC W/AN AREA OF SHOWERS AND ISOLD TSTMS MOVING ACROSS NW
MAINE TOWARD NE MAINE. LATEST MESO ANALYSIS SHOWED THE BEST
INSTABILITY RESIDING IN THIS REGION AS SHOWN BY THE LIFTED INDEX
OF -2 TO -4 RUNNING FROM QUEBEC THROUGH NW MAINE. FURTHER E,
ATMOSPHERE IS MORE STABLE ATTM. THE HRRR 3KM AND THE NAM12 WERE
DOING WELL W/PLACEMENT AND INSTABILITY. A LARGE LINE OF LIGHTNING
STRIKES HAD EXTENDED FROM QUEBEC DOWN ACROSS NYS AND PA
BUT HAVE SINCE DISSIPATED. THIS IS EXPECTED TO CHANGE LATER THIS
MORNING INTO THE AFTERNOON THE FRONT CONTINUE TO PUSH E AND THE
AIRMASS DESTABILIZES. THE LATEST RUNS OF THE NAM AND GFS CONTINUE
TO SHOW THE HIGHEST THREAT FOR POSSIBLY SEVERE TSTMS W/EHI
RUNNING FROM 1 TO 2 AND SB/MU CAPES OF 1200-2000 JOULES AND 0-6KM
SHEAR OF 35-40 KTS. ANOTHER FACTOR TO CONSIDER WILL BE THE
DIRECTIONAL SHEAR THROUGH 850MBS AND LCLS MAKING THEIR DECENT FROM
5K FT DOWN TO 2500 FT. IN ADDITION TO ALL THIS WILL BE VERY HIGH
PWATS OF 1.7+ INCHES AND SWEAT INDEX OF 300+. ALL THIS WOULD
SUGGEST THE POTENTIAL FOR DAMAGING WINDS AND VERY HEAVY RAINFALL.
SOME ROTATION COULD BE SEEN IN THE STRONGER STORMS GIVEN THE
TURNING IN THE LLVLS AND THE LOWER LCLS. KEPT THE ENHANCED WORDING
FOR GUSTY WINDS AND HEAVY RAINFALL. THE WORDING MIGHT NEED TO BE
BOOSTED TO INCLUDE DAMAGING WINDS IF THINGS HOLD W/THE UPDATE
LATER THIS MORNING. TEMPERATURES WILL FALL BACK ACROSS NORTHERN
MAINE AFTER 1 PM AS THE FRONT SLIDE THROUGH WHILE THE CENTRAL
HIGHLANDS AND DOWNEAST WILL HAVE TIME TO HEAT UP W/AFTERNOON
TEMPERATURES HITTING IN THE LOWER 80S. SPC HAS KEPT THE SLIGHT
RISK FOR SEVERE WEATHER FOR OUR REGION IN PLACE FOR TODAY.
THE COLD FRONT IS FORECAST TO SLIDE INTO THE COASTAL WATERS THIS
EVENING W/PARTIAL CLEARING TAKING PLACE AND A DRAMATIC COOLDOWN.
WE ARE TALKING 10-15 DEGREES COOLER THAN WHAT WE HAVE SEEN THAT
LAST FEW MORNINGS. SOME OF THE SITES BACK TO THE W AND NW COULD
DROP BACK INTO THE UPPER 30S BY EARLY MONDAY MORNING.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
AT THE START OF THE NEAR TERM PERIOD. A COLD FRONT WILL BE
EXTENDED ALONG THE COAST OF MAINE. HIGHER PRESSURE WILL BEGIN TO
BUILD INTO THE AREA. COOLER DRIER AIR WILL MOVE INTO THE AREA WITH
THE HIGH. DAY TIME TEMPS SUNDAY IN THE MID 60S AND LOWER 60S
MONDAY. OVERNIGHT LOWS IN THE LOWER 40S. THE HIGH PRESSURE RIDGE
WILL DOMINATE THE WEATHER THROUGH THE NEAR TERM PERIOD OF THE
FORECAST.
LOADED A BLEND OF THE GFS/NAM/GEM/ECMWF FOR HRLY
TEMPS/DP...WND...POP... AND SKY. NAWAVE 4 FOR SEAS IN THE COASTAL
WATERS. ADDED 15 PERCENT TO WINDS FOR GUSTS OVER LAND...25 PERCENT
OVER COASTAL WATERS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A HIGH PRESSURE RIDGE WILL BE IN PLACE OVER THE AREA AT THE START
OF THE LONG TERM. A LOW PRESSURE SYSTEM MOVING UP THE EAST COAST
AT THE START OF THE PERIOD THE GFS PLACES IT ALONG THE GULF STREAM
EAST OF NJ...THE ECMWF ALONG THE COAST OF VA. AND THE GEM PLACES
IT EAST OF CAPE COD...SOUTH OF SW NOVA SCOTIA. BY WED MRNG THE GFS
MOVES THE LOW NORTH TO JUST SOUTH OF CAPE COD...WITH THE PRECIP
SHIELD EXTENDING INTO DOWNEAST MAINE...THE ECMWF MOVES THE LOW TO
DELMARVA...KEEPS THE PCPN SHIELD SOUTH OF CAPE COD. THE GEM MOVES
THE LOW TO A POSITION SOUTH OF CENTRAL NOVA SCOTIA WELL EAST OF
OUR AREA. A NEW LOW OVER THE CENTRAL MIDWEST WITH A COLD FRONT
THAT EXTENDS FROM NORTHERN QUEBEC SW TO THE CENTRAL GREAT LAKES
REGION. THE LOW WILL MOVE EAST AND BY THUR MRNG THE GFS MOVE IT TO
THE ERN GREAT LAKES REGION...WITH ITS WARM FRONT EXTENDING INTO
NRN MAINE. THE ECMWF IS A BIT SLOWER WITH THE FORWARD MVMNT OF
THIS LOW...MOVING IT TO LAKE HURON. BY THURS EVNG...THE ECMWF
CATCHES UP A BIT. THE GFS MOVES THE LOW TO SRN QUEBEC/WRN MAINE.
THE ECMWF MOVES THE LOW TO SW QUEBEC. FROM THURS EVNG THROUGH THE
END OF THE PERIOD. THE GFS AND ECMWF ARE ABOUT ONE PERIOD OUT OF
FAZE WITH THE GFS BEING THE FASTER OF THE TWO MODELS. UNSETTLED
WEATHER WILL PERSIST FROM THURS EVNG THROUGH THE END OF THE PERIOD
AS AN UPPER LOW SLOWLY FILLS OVER WEST CENTRAL QUEBEC SE OF JAMES
BAY.
LOADED THE SUPERBLEND FOR THE EXTENDED PERIOD OF THE FORECAST.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: IFR SETTING UP ACROSS KBHB AND POSSIBLY KBGR THIS
MORNING WHILE THE NORTHERN TERMINALS WILL SEE VFR THIS MORNING
GOING TO MVFR. MVFR CONDITIONS FOR ALL TERMINALS INTO THE
AFTERNOON. VFR EXPECTED ACROSS THE NORTHERN TERMINALS TONIGHT
WHILE KBGR AND KBHB COULD SEE A BRIEF PERIOD OF IFR BEFORE
CLEARING LATER TONIGHT AS THE FRONT CLEARS THE AREA.
SHORT TERM: A FEW STRAY SHOWERS FOR BGR AND BHB EARLY IN THE
PERIOD...OTHERWISE VFR CONDITIONS ALL SITES.
&&
.MARINE...
NEAR TERM: CONDITIONS ATTM BELOW SCA LEVELS BOTH IN THE WINDS AND
SEAS W/15 KTS AND 4 TO 5 FT. WINDS AND SEAS ARE EXPECTED TO INCREASE
TO SCA LEVELS LATER THIS MORNING INTO THE AFTERNOON AS THE LLVL
JET OF 35 KTS MOVES ACROSS THE WATERS. WINDS DROP OFF BEHIND THE
FRONT TO LESS THAN 15 KTS AND SEAS WILL COME DOWN AS THE WIND GOES
OFFSHORE.
SHORT TERM: WINDS AND SEAS BELOW SCA CRITERIA THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ050-
051.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...NORTON
LONG TERM...NORTON
AVIATION...HEWITT/NORTON
MARINE...HEWITT/NORTON
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1242 PM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL BRING SHOWERS AND THUNDERSTORMS TODAY...WITH
MUCH COOLER TEMPERATURES SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
QUICK EARLY AFTERNOON UPDATE TO SLIGHTLY PUSH BACK TIMING OF
FRONT. STILL ANTICIPATE ONLY WIDELY SCATTER RED THUNDERSTORM
COVERAGE TODAY SOUTH AND EAST OF PITTSBURGH AS CLOUD COVER WILL
KEEP LOCATIONS NORTH AND WEST FROM REACHING TRIGGER TEMPERATURES
AND LIFT ASSOCIATED WITH THE FRONT IS RELATIVELY WEAK. PREV
DISCUSSION FOLLOWS..
LATEST RADAR/SAT/SFC OBS INDICATE THE ANAFRONT APPROACHING FROM
THE WEST JUST NORTH AND EAST OF THE FORECAST AREA DRAPED ALONG THE
SOUTHERN EDGE OF LAKE ERIE AND THEN DROPPING SOUTH JUST EAST OF
CINCINNATI. ASSOCIATED PRECIPITATION ALONG AND JUST BEHIND THE
FRONT HAS BEEN MAINLY LIGHT SHOWERS...BUT AS THE FRONT SLOWLY
TRANSITIONS EAST ISOLATED THUNDERSTORMS SHOULD DEVELOP AS WELL
OVER AREAS WHERE THERE HAS BEEN SUFFICIENT SFC HEATING TO
CONTRIBUTE TO INSTABILITY. THE 12Z NAM APPEARS TO HAVE TRENDED
SLOWER...WHICH IS GOOD AS ALL 00Z AND 06Z RUNS LOOKED TOO FAST
WITH THE PROGRESSION OF THE FRONT. THE GFS AND LOCALLY RUN HIRES
WRF MODELS WHICH USE GFS BOUNDARY CONDITIONS SEEMED TO HAVE THE
BEST HANDLE ON THE SITUATION AND ADJUSTMENTS TO THE FORECAST FOR
TODAY WERE LARGELY BASED ON THAT ALONG WITH 12Z SOUNDING
DATA...WITH LAST MINUTE TWEAKS AS THE 12Z HRRR RUN FINALLY BEGAN
TO SLOW THINGS DOWN AS WELL. WITH THAT...HAVE PARED BACK THE
PRECIPITATION FORECAST BY CUTTING BACK ON PREFRONTAL AND
POSTFRONTAL POPS AS THERE IS BETTER CONFIDENCE IN TIMING.
BY THIS EVENING THE FRONT SHOULD BE LARGELY SOUTH OF THE FORECAST
AREA WITH MUCH DRIER AIR AND COOLER TEMPERATURES IN ITS WAKE.
TEMPERATURES TODAY WILL BE HIGHEST SOUTH AND EAST OF PITTSBURGH
NEAR 80...WITH LOWER TO MID 70S FAR NORTH.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
DRY HIGH PRESSURE WILL DOMINATE THROUGH SUNDAY NIGHT.
AS HIGH SHIFTS EAST MONDAY MODELS AGREE ON LOW PRESSURE
DEVELOPING ALONG THE MID ATLANTIC COAST BUT DIFFER ON PLACEMENT OF
DEEPER MOISTURE. WOULD EXPECT BULK OF ANY ACTIVITY TO REMAIN EAST
OF THE RIDGES AND HAVE LOW CHC TO CHC POPS MONDAY IN THE SOUTHEAST
RIDGES. BY TUESDAY A SHORTWAVE WILL WORK QUICKLY EAST IN ZONAL
FLOW WITH INCREASING LOW AND MID LEVEL MOISTURE. WITH A RATHER
WEAK SYSTEM HAVE GONE WITH SLIGHT CHANCE POPS. TEMPERATURES WILL
REBOUND TO ABOVE SEASONAL AVERAGES BY TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
INCRG PCPN CHCS ARE EXPD WED INTO THU AS LOW PRES ADVNS ACRS THE GT
LKS AND UPR OH VLY RGN. SFC HIGH PRES WL BLD IN BY LT WK INTO THE
WKEND UNDER GENL COOL NERN CONUS UPR TROFG. THE COOL UPR TROFG WL
ALLOW TEMPS TO FALL FM NR SEASONAL LVLS MID WK...TO SVRL DEG BLO AVG
BY LT WK INTO THE WKEND.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
GENL VFR CONDS ARE EXPD UNTIL A CDFNT ADVNS ACRS THE RGN TDA WITH
MVFR CONDS IN CU/SC AND OCNL SHWRS EXPD. BEST CHC FOR AFTN TSTMS
EXPD TO BE S OF PIT WITH BETTER INSTBY SO INCLUDED A TEMPO TS
MENTION IN THE MGW TAF. EXP A WSHFT FM SW TO NW WITH FROPA...AND
AN EVENTUAL CLRG TREND BY THIS EVE AS THE FNT FURTHER EXITS. AREAS
OF MVFR FOG IS EXPD TO DVLP LT TNGT ESP WHERE CLRG TAKES PLACE AFT
SUNSET.
OUTLOOK.../SUNDAY THROUGH WEDNESDAY/...
RSTRNS ARE PSBL WITH A MD WK LOW PRES SYSTEM.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1034 AM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL BRING SHOWERS AND THUNDERSTORMS TODAY...WITH
MUCH COOLER TEMPERATURES SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST RADAR/SAT/SFC OBS INDICATE THE ANAFRONT APPROACHING FROM
THE WEST JUST NORTH AND EAST OF THE FORECAST AREA DRAPED ALONG THE
SOUTHERN EDGE OF LAKE ERIE AND THEN DROPPING SOUTH JUST EAST OF
CINCINNATI. ASSOCIATED PRECIPITATION ALONG AND JUST BEHIND THE
FRONT HAS BEEN MAINLY LIGHT SHOWERS...BUT AS THE FRONT SLOWLY
TRANSITIONS EAST ISOLATED THUNDERSTORMS SHOULD DEVELOP AS WELL
OVER AREAS WHERE THERE HAS BEEN SUFFICIENT SFC HEATING TO
CONTRIBUTE TO INSTABILITY. THE 12Z NAM APPEARS TO HAVE TRENDED
SLOWER...WHICH IS GOOD AS ALL 00Z AND 06Z RUNS LOOKED TOO FAST
WITH THE PROGRESSION OF THE FRONT. THE GFS AND LOCALLY RUN HIRES
WRF MODELS WHICH USE GFS BOUNDARY CONDITIONS SEEMED TO HAVE THE
BEST HANDLE ON THE SITUATION AND ADJUSTMENTS TO THE FORECAST FOR
TODAY WERE LARGELY BASED ON THAT ALONG WITH 12Z SOUNDING
DATA...WITH LAST MINUTE TWEAKS AS THE 12Z HRRR RUN FINALLY BEGAN
TO SLOW THINGS DOWN AS WELL. WITH THAT...HAVE PARED BACK THE
PRECIPITATION FORECAST BY CUTTING BACK ON PREFRONTAL AND
POSTFRONTAL POPS AS THERE IS BETTER CONFIDENCE IN TIMING.
BY THIS EVENING THE FRONT SHOULD BE LARGELY SOUTH OF THE FORECAST
AREA WITH MUCH DRIER AIR AND COOLER TEMPERATURES IN ITS WAKE.
TEMPERATURES TODAY WILL BE HIGHEST SOUTH AND EAST OF PITTSBURGH
NEAR 80...WITH LOWER TO MID 70S FAR NORTH.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
DRY HIGH PRESSURE WILL DOMINATE THROUGH SUNDAY NIGHT.
AS HIGH SHIFTS EAST MONDAY MODELS AGREE ON LOW PRESSURE
DEVELOPING ALONG THE MID ATLANTIC COAST BUT DIFFER ON PLACEMENT OF
DEEPER MOISTURE. WOULD EXPECT BULK OF ANY ACTIVITY TO REMAIN EAST
OF THE RIDGES AND HAVE LOW CHC TO CHC POPS MONDAY IN THE SOUTHEAST
RIDGES. BY TUESDAY A SHORTWAVE WILL WORK QUICKLY EAST IN ZONAL
FLOW WITH INCREASING LOW AND MID LEVEL MOISTURE. WITH A RATHER
WEAK SYSTEM HAVE GONE WITH SLIGHT CHANCE POPS. TEMPERATURES WILL
REBOUND TO ABOVE SEASONAL AVERAGES BY TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
INCRG PCPN CHCS ARE EXPD WED INTO THU AS LOW PRES ADVNS ACRS THE GT
LKS AND UPR OH VLY RGN. SFC HIGH PRES WL BLD IN BY LT WK INTO THE
WKEND UNDER GENL COOL NERN CONUS UPR TROFG. THE COOL UPR TROFG WL
ALLOW TEMPS TO FALL FM NR SEASONAL LVLS MID WK...TO SVRL DEG BLO AVG
BY LT WK INTO THE WKEND.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
GENL VFR CONDS ARE EXPD UNTIL A CDFNT ADVNS ACRS THE RGN TDA WITH
MVFR CONDS IN CU/SC AND OCNL SHWRS EXPD. BEST CHC FOR AFTN TSTMS
EXPD TO BE S OF PIT WITH BETTER INSTBY SO INCLUDED A TEMPO TS
MENTION IN THE MGW TAF. EXP A WSHFT FM SW TO NW WITH FROPA...AND
AN EVENTUAL CLRG TREND BY THIS EVE AS THE FNT FURTHER EXITS. AREAS
OF MVFR FOG IS EXPD TO DVLP LT TNGT ESP WHERE CLRG TAKES PLACE AFT
SUNSET.
OUTLOOK.../SUNDAY THROUGH WEDNESDAY/...
RSTRNS ARE PSBL WITH A MD WK LOW PRES SYSTEM.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
715 PM EDT SUN SEP 7 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 358 PM EDT SUN SEP 7 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR LAKES BTWN A BROAD UPR RDG OVER WRN NAMERICA AND A TROF OVER
THE NE STATES. SHRTWV EMBEDDED IN THIS WNW FLOW WHICH WAS RESPONSIBLE
FOR CLOUD COVER AND ISOLD SHRA OVER ERN LAKE SUPERIOR HAS NOW MOVED
EAST OF LAKE SUPERIOR WITH CLOUD COVER GENERALLY ERODING. ANOTHER
SHORTWAVE MOVING EAST THROUGH SOUTH DAKOTA HAS GENERATED SOME WAA
CLOUDS OVER ERN SD BUT NO PCPN AT THIS TIME AS AIR MASS VERY DRY AS
NOTED ON 12Z ABR SNDG.
MAIN FCST CONCERNS WILL FOCUS MAINLY ON TEMPS AND CLOUDS AS AIRMASS
LOOKS TO BE TOO DRY FOR PCPN OVER THE NEXT 24 HRS.
TNGT...TIGHTENING PRES GRADIENT BTWN HI PRES RETREATING TOWARD NEW
ENGLAND AND LO PRES TAKING SHAPE SW OF LK WINNIPEG WILL ALLOW FOR AN
INCREASE IN SSW WIND ACROSS THE AREA TONIGHT. ALTHOUGH THE AIRMASS
WL BE DRY AND SKIES MOSTLY CLR WITH PWATS AROUND 0.75 INCH...THE
STEADY WIND WL TEND TO LIMIT THE DIURNAL TEMP DROP...ESPECIALLY IN
THE DOWNSLOPE AREAS NEAR LK SUP OVER NW UPR MI. EXPECT THE LOWEST
MIN TEMPS (MID TO UPPER 40S) OVER THE INTERIOR ALONG THE WI BDR AND
E WHERE THE PRES GRADIENT WL BE A BIT WEAKER/WINDS LIGHTER.
CONVERSELY MIN TEMPS FOR DOWNSLOPING AREAS ALONG LAKE SUPERIOR WILL
STAY UP IN THE MID TO UPPER 50S.
WAA WILL CONTINUE ON MONDAY WITH INCREASING S WINDS AS UPPER MI
REMAINS STUCK BETWEEN A LARGE AREA OF HIGH PRESSURE EXITING THE NEW
ENGLAND STATES...AND AN ELONGATED LOW PRES TROUGH SET UP FROM THE
CENTRAL PLAINS THROUGH ONTARIO AND HUDSON BAY. 850MB TEMPS WILL
AVERAGE 11-12C BY THE END OF THE DAY SHOULD YIELD HIGH TEMPS IN THE
MID TO UPPER 70S ACROSS THE AREA DESPITE SOME INCREASE IN WAA CLOUDS
AHEAD OF APPROACHING PLAINS SHORTWAVE. SOUTH GUSTS NEAR 20KTS WILL BE
COMMON IN THE AFTERNOON. GIVEN DRY AIRMASS IN PLACE HAVE ELECTED TO
KEEP FCST DRY FOR NOW DESPITE SOME WEAK FORCING AHEAD OF PLAINS
SHORTWAVE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 PM EDT SUN SEP 7 2014
MONDAY NIGHT INTO TUESDAY WILL BE THE TRANSITION PERIOD FROM THE
DRY AND RELATIVELY WARM HIGH PRESSURE DEPARTING THE AREA TO THE
MUCH COOLER AND WET PERIOD IN STORE FOR THE SECOND HALF OF THE WORK
WEEK. THE START OF THIS TRANSITION WILL BE A COLD FRONT EXTENDING
SOUTHWEST FROM A LOW NEAR HUDSON BAY. THIS FRONT WILL SLOWLY SHIFT
TO THE EAST OUT OF MINNESOTA ON MONDAY NIGHT AND INTO WESTERN LAKE
SUPERIOR AND THE WESTERN U.P. TUESDAY. EXPECT ISOLATED/SCATTERED
SHOWERS TO OCCUR ALONG THIS FRONT AS IT SLOWLY MOVES EAST ACROSS THE
U.P. LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT. DID CONTINUE TO
INCLUDE A SLIGHT CHANCE OF THUNDER ON THE EAST SIDE OF THE
FRONT/TROUGH DUE TO THE INSTABILITY INCREASING UNDER THE SOUTHERLY
FLOW DURING THE AFTERNOON BEFORE DIMINISHING IN THE EVENING.
THIS SLOW MOVING TROUGH WILL BE THE FOCUS FOR THE TRACK OF THE
STRONG LOW PRESSURE SYSTEM THAT WILL BE DEVELOPING IN THE CENTRAL
PLAINS ON TUESDAY AND THEN QUICKLY LIFTING NORTHEAST THROUGH THE
UPPER GREAT LAKES REGION WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT.
STILL SOME DIFFERENCES IN THE LOW TRACK BETWEEN THE OPERATIONAL
MEMBERS AND ITS LOCATION AT 00Z THURSDAY...BUT THE 00Z ECMWF OR 12Z
GEM RUNS SEEM TO BE A GOOD COMPROMISE WITH THE OTHER MODELS AND
ENSEMBLE MEMBERS. THIS CONSENSUS TRACKS A LOW-MID 990MB LOW FROM
SOUTHEAST MINNESOTA AT 12Z WEDNESDAY TO NORTHERN LAKE MICHIGAN BY
00Z THURSDAY AND INTO QUEBEC ON THURSDAY. 06Z GFS AND 00Z ECMWF
ENSEMBLE MEMBERS SUPPORT THAT IDEA AND AWAY FROM THE FASTER AND
FARTHER EAST SOLUTION SEEN ON THE 12Z GFS. WITH THAT IDEA IN
MIND...EXPECT A TRANSITION FROM THE LIGHTER PRECIP ASSOCIATED WITH
THE SURFACE TROUGH OVER WESTERN/CENTRAL U.P. ON TUESDAY NIGHT TO
WIDESPREAD RAIN LIFTING NORTHEAST ACROSS THE AREA ON WEDNESDAY.
WILL CONTINUE TO SHOW INCREASING POPS DURING THAT PERIOD AS THE
ISENTROPIC ASCENT PUSHES THROUGH THE AREA AND DECIDED UP THE
WEDNESDAY POPS TO DEFINITE VALUES ACROSS THE CWA. DID ADD A SMALL
POCKET OF THUNDER ALONG THE LAKE MICHIGAN BORDER WEDNESDAY WHERE THE
SURFACE LOW WILL TRACK AND POCKET OF ELEVATED INSTABILITY WOULD BE
LOCATED. AS THE LOW LIFTS NORTHEAST ON WEDNESDAY NIGHT...EXPECT THE
RAIN TO LINGER THE LONGEST OVER THE WEST AND ESPECIALLY THE KEWEENAW
PENINSULA WHICH WILL BE JUST TO THE WEST/NORTHWEST OF THE 850/700MB
LOW TRACK. WITH THE INITIAL SURGE OF PRECIPITATION ASSOCIATED WITH
THIS LOW...HAVE RAINFALL AMOUNTS OVER AN 1.25 INCH ACROSS THE ENTIRE
AREA THROUGH WEDNESDAY NIGHT AND THE HIGHEST AMOUNTS OVER NORTHWEST
UPPER MICHIGAN (AMOUNTS OF 1.5-2IN). IN ADDITION TO THE RAIN...WINDS
WILL BE ON THE INCREASE FROM WEST TO EAST WEDNESDAY AFTERNOON INTO
WEDNESDAY NIGHT WITH SOLID NORTHERLY GALES OVER LAKE SUPERIOR.
EXPECT THE STRONG WINDS TO AFFECT THE SHORELINE AREAS WEDNESDAY
NIGHT (GUSTS TO 35KTS) BEFORE GRADUALLY DECREASING THURSDAY THROUGH
FRIDAY. HAVE WINDS RIGHT AROUND WIND ADVISORY CRITERIA OVER
NORTHERN PORTIONS OF THE KEWEENAW PENINSULA AND EVEN IF THEY DON/T
REACH CRITERIA...THERE COULD BE DECENT IMPACTS WITH A SATURATED
GROUND AND LEAVES ON THE TREES HELPING TO CAUSE SOME TREES TO FALL
DOWN.
THE NORTHWEST FLOW BEHIND THE LOW WILL USHER IN COLD AIR ALOFT (850
TEMPS OF -1C BY 18Z THURSDAY) AND LEAD TO LAKE EFFECT RAIN UNDER
NORTHWEST FLOW UNTIL THE SECOND WAVE AND TROUGH AXIS MOVES THROUGH
THURSDAY NIGHT INTO FRIDAY. THIS WILL BRING ANOTHER AREA OF
WIDESPREAD LIGHT RAIN SHOWERS TO THE AREA. BEHIND THAT SECOND
WAVE...EXPECT DRYING CONDITIONS AS AN UPPER/SURFACE RIDGE MOVE INTO
THE AREA THROUGH SUNDAY MORNING. DEPENDING ON HOW QUICKLY SKIES
CLEAR ON FRIDAY NIGHT...COULD SEE LOWS NEARING FREEZING. THINK
BEST CHANCE WOULD BE OVER THE INTERIOR WEST AS IS TRADITIONALLY
THE CASE WITH BACKING LOW LEVEL WINDS. THURSDAY THROUGH SATURDAY
WILL BE A COOL STRETCH AND EXPECT HIGHS TO BE IN THE 50S EACH DAY.
OVER THE WEST ON THURSDAY/FRIDAY...COULD SEE SOME LOCATIONS
STRUGGLING TO RISE OUT OF THE UPPER 40S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 715 PM EDT SUN SEP 7 2014
EXPECT VFR CONDITIONS THIS FCST PERIOD. DAYTIME HEATING/MIXING WL
ALLOW FOR GUSTY WINDS TO 15-20 KT MON AFTN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 358 PM EDT SUN SEP 7 2014
LARGE HIGH PRESSURE STRETCHING FROM THE CENTRAL PLAINS THROUGH THE
LOWER GREAT LAKES WILL EXIT TO THE NEW ENGLAND STATES TONIGHT.
MEANWHILE...A LOW PRES TROUGH WILL DEVELOP FROM HUDSON BAY THROUGH
WRN ONTARIO INTO THE NRN PLAINS. LOW PRES DEVELOPING OVER THE
CENTRAL PLAINS BY TUE WILL MOVE NE ACROSS THE UPPER GREAT LAKES LATE
WEDNESDAY AND WEDNESDAY NIGHT...BEFORE EXITING INTO QUEBEC ON
THURSDAY. A PERIOD OF N GALES WILL BE POSSIBLE LATE TUE
NIGHT INTO EARLY THURSDAY. INCLUDED AREAS OF FOG OVER NCNTRL LAKE
SUPERIOR WHERE PATCH OF FOG HAS RESIDED MUCH OF THE AFTERNOON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...07
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
945 AM PDT SAT SEP 6 2014
.SYNOPSIS...A FEW SHOWERS AND THUNDERSTORMS ARE POSSIBLE ACROSS
MAINLY THE HIGHER TERRAIN OF NORTHWEST ARIZONA...FAR SOUTHERN NEVADA
AND EASTERN CALIFORNIA THIS AFTERNOON. THE REST OF THE AREA WILL SEE
DRY CONDITIONS UNDER SOUTHWEST FLOW. MOISTURE IS FORECAST TO
INCREASE SUNDAY INTO MONDAY RESULTING IN A BETTER CHANCE OF SHOWERS
AND THUNDERSTORMS ACROSS MUCH OF THE AREA. HEAVY RAIN AND FLASH
FLOODING WILL BE A CONCERN FOR MUCH OF THE MOHAVE DESERT SUNDAY
THROUGH MONDAY NIGHT.
&&
.UPDATE...NORBERT STRENGTHENED TO A CATEGORY 3 HURRICANE OVERNIGHT
BUT IS FORECAST TO WEAKEN THE REST OF TODAY AS IT DRIFTS NORTH INTO
COOLER WATERS. 12Z HI RES AND HRRR MODELS STILL INDICATE THE
POTENTIAL FOR ISOLATED CONVECTION OVER THE HIGHER TERRAIN OF MOHAVE,
CLARK AND SAN BERNARDINO COUNTY THIS AFTERNOON/EARLY EVENING. THIS
COVERED IN CURRENT FORECAST SO NOT UPDATE NECESSARY. TROPICAL
MOISTURE STILL SLATED TO SURGE NORTH INTO THE AREA SUNDAY AND LINGER
THROUGH TUESDAY. WILL ADDRESS ANY CHANGES FOR THOSE PERIODS THIS
AFTERNOON.
&&
.PREV DISCUSSION...
304 AM PDT SAT SEP 6 2014
.SHORT TERM...THROUGH SUNDAY NIGHT...THE MOISTURE SURGE THAT STARTED
YESTERDAY HAS TAKEN A BIT OF A PAUSE. SURFACE DEWPOINTS EARLY THIS
MORNING WERE IN THE 20S AND 30S IN THE NORTHWEST PART OF THE CWA
WITH 40S AND 50S SOUTHEAST. NOT EXPECTING MUCH NORTHWARD PROGRESS OF
THE MOISTURE TODAY WITH A SLIGHT CHANCE OF THUNDERSTORMS LIMITED TO
GENERALLY AREAS SOUTHEAST OF LAS VEGAS. HURRICANE NORBERT IS
FORECAST TO WEAKEN AND TRACK NORTHWEST THEN NORTH JUST WEST OF BAJA
FOR THE NEXT FEW DAYS. AS A RESULT...MOISTURE WILL GRADUALLY
INCREASE TONIGHT THROUGH SUNDAY NIGHT. PRECIPITABLE WATER VALUES BY
SUNDAY NIGHT ARE FORECAST TO BE AROUND 2 INCHES AROUND LAKE HAVASU
WITH ONE INCH VALUES APPROACHING THE NORTHERN EDGE OF OUR FORECAST
AREA. PRECIPITATION CHANCES WILL STILL BE LIMITED TO AREAS SOUTHEAST
OF LAS VEGAS TONIGHT BUT WILL SPREAD ACROSS THE REST OF THE FORECAST
AREA SUNDAY AND SUNDAY NIGHT. WITH SUCH DEEP MOISTURE ACROSS THE
MOHAVE DESERT...SHOWERS AND THUNDERSTORMS THAT DEVELOP WILL BE
EFFICIENT RAINFALL PRODUCERS...LEADING TO A THREAT OF FLASH FLOODING
AND THE FLASH FLOOD WATCH STILL LOOKS GOOD.
.LONG TERM...MONDAY THROUGH FRIDAY.
MONDAY...BY MONDAY MORNING WIDESPREAD DEEP MOISTURE [SOME OF WHICH
WILL BE ASSOCIATED WITH THE REMNANTS OF WHAT IS CURRENTLY HURRICANE
NORBERT] IS FORECAST TO BE IN PLACE ACROSS MOST IF NOT ALL OF THE
FORECAST AREA. THE LATEST 00Z LAS VEGAS GFS BUFR SOUNDING FOR 15Z
MONDAY INDICATES A PEAK PRECIPITABLE WATER VALUE OF 1.89 INCHES
WHICH WOULD CHALLENGE THE SEPTEMBER RECORD OF 1.88 INCHES WHICH WAS
SET ONLY LAST YEAR. IN FACT SO MUCH MOISTURE WILL BE IN PLAY THAT
SIGNIFICANT CLOUD COVERAGE WILL LIKELY LIMIT
SIGNIFICANT...WIDESPREAD DESTABILIZATION MONDAY. FORECAST SOUNDINGS
ACROSS THE REGION SHOW SLIGHT WARMING ALOFT WHILE LOW LEVEL
TEMPERATURES COOL. AS A RESULT I HAVE BOOSTED POPS AREA WIDE BUT AT
THIS POINT IT APPEARS THAT PRECIPITATION MAY FALL MAINLY AS LIGHT TO
MODERATE RAIN SHOWERS WITH ISOLATED TO SCATTERED EMBEDDED
THUNDERSTORMS WITH HEAVY RAIN [HAVE ADJUSTED THE WEATHER GRIDS
ACCORDINGLY]. MODELS ARE IN DECENT AGREEMENT THAT THE BEST CHANCES
FOR RAIN WILL BE NORTHEAST OF A TONOPAH-PAHRUMP-PARKER LINE
ASSOCIATED WITH UPPER LEVEL DIVERGENCE AHEAD OF AN UPPER LEVEL
SHORTWAVE SWINGING THROUGH CALIFORNIA. THAT SAID...CHANCES OF RAIN
AND THUNDERSTORMS EXIST ACROSS THE ENTIRE REGION. PRECIPITATION
CHANCES WILL CONTINUE THROUGH MONDAY NIGHT.
TUESDAY...ON TUESDAY THE AFOREMENTIONED SHORTWAVE WILL PUSH EAST
ACROSS THE FORECAST AREA. THIS WILL PROVIDE ENOUGH DYNAMICS FOR
ANOTHER DAY OF ISOLATED TO SCATTERED CONVECTION ACROSS MUCH OF THE
AREA. THE BEST CHANCES WILL BE ACROSS LINCOLN...CLARK AND MOHAVE
COUNTIES. HOW MUCH THUNDERSTORM ACTIVITY THAT DEVELOPS WILL AGAIN BE
STRONGLY TIED TO THE AMOUNT OF CLOUD COVER THROUGH THE MORNING/EARLY
AFTERNOON HOURS. AT THIS POINT IT APPEARS THAT IT MAY BE A GAME TIME
DECISION AS TO WHETHER THE FLASH FLOOD WATCH WILL NEED TO BE
EXTENDED THROUGH TUESDAY. DRIER AIR WILL BEGIN TO FILTER IN FROM THE
WEST THROUGH THE DAY SHUTTING DOWN PRECIP CHANCES.
WEDNESDAY THROUGH FRIDAY...LEFT IN JUST A SLIGHT CHANCE OF
PRECIPITATION ACROSS EASTERN MOHAVE COUNTY WEDNESDAY TO ACCOUNT FOR
ANY RESIDUAL MOISTURE IN PLACE. OTHERWISE DRIER CONDITIONS AND
REBOUNDING TEMPERATURES ARE EXPECTED.
&&
.AVIATION...FOR MCCARRAN...EASTERLY COMPONENT LATE THIS
MORNING/AFTERNOON UP TO 10 KTS AT TIMES. WINDS WILL BECOME MORE
SOUTHEASTERLY OR SOUTHERLY AGAIN THIS AFTERNOON OR EARLY THIS
EVENING AROUND 10KTS...CONTINUING TONIGHT. CLEAR SKIES EARLY TODAY
WITH FEW-SCT CUMULUS CLOUDS DEVELOPING LATE THIS MORNING AND THIS
AFTERNOON. CLOUDS AND THUNDERSTORM CHANCES WILL BE INCREASING SUNDAY
THROUGH MONDAY AS MOISTURE FROM HURRICANE NORBERT SPREADS NORTHWARD.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS THIS
AFTERNOON OVER MAINLY NORTHWEST ARIZONA AND EASTERN SAN BERNARDINO
COUNTY. CLOUDS AND THUNDERSTORM CHANCES WILL BE INCREASING SUNDAY
THROUGH MONDAY AS MOISTURE FROM HURRICANE NORBERT SPREADS NORTHWARD.
WINDS SHOULD FOLLOW TYPICAL DIURNAL TRENDS THROUGH THE TAF PERIOD.
LIGHT DRAINAGE WINDS THROUGH EARLY THIS MORNING WILL BECOME MAINLY
SOUTHERLY DURING THE DAY GENERALLY 10-15 KTS.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT EXPECTED THROUGH SATURDAY. SPOTTER
ACTIVATION MAY BE NEEDED FOR CLARK, MOHAVE AND SAN BERNARDINO
COUNTIES OF THE FORECAST AREA SUNDAY THROUGH TUESDAY.
&&
$$
UPDATE...PIERCE
SHORT TERM/AVIATION...HARRISON
LONG TERM...WOLCOTT
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
149 AM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE EASTERN GREAT LAKES TONIGHT
BRINGING A FEW SHOWERS OR THUNDERSTORMS TO UPSTATE NEW YORK
MAINLY. THIS COLD FRONT WILL CROSS THE REGION SATURDAY WITH MORE
WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY. ONCE THIS FRONT
PASSES BY SATURDAY NIGHT...HIGH PRESSURE WITH COOLER AND LESS
HUMID WEATHER WILL RETURN FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
950 PM UPDATE...
A LINE OF INTENSE CONVECTION EXTENDS FROM LOWER ONTARIO BACK
THROUGH ILLINOIS AT THIS HOUR. THE NORTHERN EDGE OF THE CONVECTION
IS SHOWING SIGNS OF WEAKENING, WHILE THE MORE INTENSE PORTION OF
THE LINE IS DIVING INTO THE UNSTABLE AIR OVER THE OHIO VALLEY
(MLCAPES 2000-2500 J/KG). THIS OBSERVED TREND IS IN AGREEMENT
WITH THE LATEST HRRR RUN, WHICH BRINGS A FEW THUNDERSTORMS INTO
SOUTHWESTERN NY AROUND 6Z AND WEAKENS THEM CONSIDERABLY.
MAKING A FEW TIMING ADJUSTMENTS TO THE POPS GRIDS FOR THE
OVERNIGHT HOURS...OTHERWISE THE GRIDS APPEAR TO BE IN GOOD SHAPE.
4 PM DISC...
RADARS SHOW SCATTERED SHOWERS AND SOME THUNDERSTORMS FIRING
OVER THE CENTRAL MTNS OF PENNSYLVANIA WITH THE DIURNAL HEATING AND
LOCALIZED MTN AND VALLEY CIRCULATIONS AS UPPER FORCING IS RATHER
WEAK. SPC MESOANALYSIS SHOWS CAPES OF 1000 J/KG TO 1500 J/KG
ACROSS MOST OF THE FINGER LAKES AND IN NORTHEAST PA WITH CAPES
LESS THAN 1000 J/KG FARTHER NORTH TO THE UPPER MOHAWK VALLEY.
WATER VAPOR IMAGERY CONTINUES TO SHOW AN ELONGATED PV MAXIMUM ON
THE SOUTHERN EDGE OF THE WESTERLIES ACROSS THE OHIO VALLEY TO
LOWER MISSISSIPPI VALLEY HEADING NORTHEAST INTO NE PA AND CENTRAL
AND EASTERN NY STATE. ALL SYNOPTIC AND MESOSCALE MODELS BRING THIS
SHEARING OUT WEAKENING FEATURE THRU C NY AND NE PA BY LATE
AFTERNOON OR EARLY EVENING. AS THIS FEATURE PASSES BY I STILL CUD
SEE AN ISLD SHOWER OR THUNDERSTORM OVER THE HIGHER TERRAIN OF THE
POCONOS WHERE LOCALIZED UPSLOPE AND MTN-VLLY CIRCULATIONS CUD
TRIGGER SOMETHING. REST OF AREA I DON/T SEE ANYTHING FORMING OF
SIGNIFANCE THIS EVENING. SO I WILL MAINTAIN SLGHT CHC POPS FOR
SHRA/TSRA UNTIL JUST AFTER 00Z WITH LOSS OF DAY/S HEATING IN THE
POCONOS.
NEXT FEATURE TO WATCH IN THE NEAR TERM WAS THE REMNANTS OF AN MCS
TRACKING E-NE ACROSS LAKE HURON INTO SRN ONT. THE MEAN WINDS IN
THE 850 MB TO 300 MB STEERING LAYER WERE FROM 250 DEGREES WITH THE
INFLOW FOR THE STORMS FROM THE SOUTHWEST. THIS WILL KEEP THESE
SHRA AND STORMS MOVING TO THE E AND MAINLY N OF C NY AND NE PA
LATE AFTERNOON OR EARLY EVENING. BUT LATER TONIGHT...A STRONG
UPPER LEVEL WAVE OVER JAMES BAY CANADA WITH ASSCTD STRONG SURFACE
LOW WHICH TRIGGERED THIS MCS WILL PASS FARTHER EAST. THIS WILL
PUSH A COLD FRONT SOUTHWARD. HENCE THE REMNANTS OF THIS MCS WILL
BECOME REFOCUSED ALONG THIS COLD FRONT AND HEAD DOWN INTO NY STATE
OVERNIGHT. THIS WILL OCCUR WHEN THE INSTABILITY IS AT ITS DIURNAL
MINIMUM SO I EXPECT ACVTY WILL WANE AS IT DROPS S TO THE PA BRDR
LATE TONIGHT AND EVENTUALLY FIZZLE. HAVE HIGHER POPS FOR SHRA/TSRA
IN NC NY OVERNIGHT AND LOWER POPS FARTHER S WITH SLGHT CHC INTO
NRN PA LATE TONIGHT.
FOR SATURDAY...LOBE OF UPPER LEVEL PV FROM THE NRN PLAINS TO THE
ROCKIES WILL RAPIDLY WORK EAST TONIGHT AND REACH THE GREAT LAKES
REGION TO CENTRAL PLAINS BY 12Z SATURDAY AND THEN INTO THE ERN
LAKES BY 00Z SUNDAY. THIS IS A POTENT FEATURE AND WILL LEAD TO
SIGNIFICANT HEIGHT FALLS...LIFTG AND COOLING ALOFT AND BE THE
IMPETUS FOR PUSHING A STRG COLD FRONT THRU NY AND PA SAT. AHEAD OF
THE COLD FRONT RICH BOUNDARY LAYER MOISTURE EXISTED WITH DEWPOINTS
APPRCHING OR ABV 70F. CAPES EASILY CUD APPROACH 1500 J/KG AHEAD OF
FRONT BETWEEN 18Z AND 00Z. WITH THE UPPER LEVEL RDG HOLDING
OFFSHORE...THE HEIGHT GRADIENT INCREASES ALSO AS THIS UPPER FEATURE
PRESSES EASTWARD WHICH INCREASES THE MID TO HIGH LEVEL WINDS AND
EVEN THE LL WINDS. HENCE WIND SHEARS WILL BE FAIRLY IMPRESSIVE.
THE 0-1 KM SHEAR WAS PROJECTED TO BE 15 TO 20 KNOTS...THE 0-6 KM
SHEAR PRIOR TO CONVECTION FIRING WAS PROGGED TO BE CLOSE TO 40
KNOTS OR SLIGHTLY MORE. HENCE BELIEVE POTENTIAL EXISTS FOR SEVERE
STORMS IN OUR FORECAST AREA MAINLY SAT PM.
FRONTAL POSITIONING WILL BE THE KEY TO WHERE THE RISK AREA IS FOR
SEVERE STORMS IN OUR FORECAST AREA. THE GFS...NAM...EURO SEEM TO
AGREE THAT BY 18Z THE INSTABILITY GRADIENT WILL RUN FROM ABT
COOPERSTOWN TO UCA SW TO BRADFORD CO INCLUDING BGM AND ELM IN OUR
FORECAST AREA. SO LOCATIONS S AND E OF HERE WILL HAVE THE HIGHEST
RISK FOR SEVERE. THE CMC IS FARTHER S AND WUD INDICATE ONLY THE
POCONOS TO SULLIVAN COUNTY SEE POTENTIAL FOR INSTABILITY AND
SEVERE WEATHER IN THE NWS BGM FORECAST AREA. OUR LOCAL SEVERE
WEATHER CHECKLIST SUGGESTS POTENTIAL FOR BROKEN LINES AND SMALL
BOW ECHOE STRUCTURES WITH WIND DAMAGE THE PRIMARY THREAT. PWATS
ALSO WERE RUNNING ARND 1.8 INCHES SO HEAVY RAIN IS ALSO WORTH
HIGHLIGHTING. NORTH OF THIS BNDRY...I SEE MAINLY SHRA IN THE
MORNING WITH ISLD THUNDER WITH THE MAIN ACVTY REMAINING TO THE S.
WILL CONTINUE TO HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
FOR SATURDAY NIGHT...FRONT PASSES E AND HIGH PRESSURE RAPIDLY
SPREADS ACROSS NY AND PA WITH LIGHT WINDS AND CLEARING SKIES AS
PER SYNOPTIC MODELS. WITH FAIRLY WIDESPREAD RAINFALL SATURDAY I
SEE PLENTY OF VALLEY FOG FORMING BY SUN AM AND HAVE IN GRIDS.
FOR SUNDAY AND SUNDAY NIGHT...HIGH PRESSURE REMAINS OVER THE
REGION WITH FAIR AND PLEASANT DAYTIME WEATHER AND A CHILLY NIGHT.
AGAIN I SEE PLENTY OF VALLEY FOG BY MONDAY AM WITH CLEAR SKIES
LIGHT WINDS AND MINS WELL DOWN INTO THE 40S MANY AREAS.
FOR MONDAY...HIGH PRESSURE WORKS E AND A SRLY RETURN FLOW BEGINS
WITH SOME MODERATING BEGINNING. I DON/T EXPECT ANY PRECIP.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
130 PM UPDATE...
EXPECT SFC HIPRES TO BE BUILDING INTO THE CANADIAN MARITIMES AT
THE START OF THE LONG TERM PD. A WEAK SFC LOW WL LKLY DVLP ALONG
THE ERN SEABOARD TUE MRNG AS WV RIDES UP ALONG THE COAST BUT WITH
1030MB HIGH CONTROLLING AREA WX NOT EXPECTING MUCH IN THE WAY OF
PCPN TO MV INTO CWA UNTIL MORE TWD TUE EVNG AND EVEN AT THAT
EXPECT IT TO BE A LONG SHOT.
CHC FOR SHOWERS/TSTMS CAN BE EXPECTED BEGINNING WED MRNG WITH
ANOTHER TROF (DEEPER ON EC VS GFS) WORKING ITS WAY INTO THE
NORTHEAST U.S. MODELS DIFFER ON POP CHANCES AFTR WED NGT WITH 12Z GFS
MUCH QUICKER MVG LOPRES THRU THAN 00Z EC. MAIN REASON IS THAT 00Z
EC IS MUCH MORE AMPLIFIED WITH SYSTEM AND DEEPER WITH SFC LOW.
THIS IS MORE IN LINE WITH GFS ENSEMBLE MEAN AND MAJORITY OF THE
ENSEMBLE MEMBERS. EXPECT TEMPS THRU THE PD TO BE NEAR.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
REMNANTS OF MCS WILL SLIDE THROUGH AT LEAST KELM-KITH EARLY THIS
MORNING...AND POSSIBLY KBGM. CONVECTIVE TRENDS HAVE BEEN SURGING
WITHIN THE LAST HOUR PRIOR TO THIS DISCUSSION...BUT ALL CONVECTION
ALLOWING MODELS SUGGEST A RAPID DISSIPATION OF ACTIVITY BY 09Z.
HAVE GONE A LITTLE HEAVIER THAN THE MODEL GUIDANCE WITH CARRYING
THE STRATIFORM RAIN INTO THE AREA...BUT THE THUNDER THREAT MAY
ACTUALLY BE WHAT DIMINISHES. AREAS OF MVFR CIGS/VSBYS SEEM FAIRLY
PLAUSIBLE...WHILE THE GUIDANCE OFFERING UP STRONG IFR SIGNALS DOES
NOT. THEN...DURING A BRIEF LULL IN RAIN ACTIVITY...THE SURFACE FRONTAL
BOUNDARY QUIETLY SLIPS THROUGH THE NORTHERN AND WESTERN HALF OF
THE REGION LATER THIS MORNING WITH MAINLY SHOWERS AND SCATTERED
MVFR RESTRICTIONS EXPECTED INTO THE MID AFTERNOON AS A POTENT
UPPER DISTURBANCE PUSHES THINGS ALONG TO THE EAST. BEST CHANCE FOR
CONVECTIVE THUNDER THREAT APPEARS TO BE AT KAVP LATER THIS
AFTERNOON...AND KBGM MAY BE JUST ON THE NORTHERN FRINGE OF THE NEW
DEVELOPMENT. DRIER AIR...AND A GRADUAL TREND TO VFR NO CIG DEVELOPS
TOWARD THE END OF THIS FORECAST. THEN...GIVEN THE RAIN...PROBLEMATIC
MVFR/IFR VSBYS COULD DEVELOP BEYOND THE VALID TIME OF THIS FORECAST
EARLY SUNDAY MORNING. WILL ADDRESS THAT LATER.
OUTLOOK...
LATE SAT NIGHT...MVFR/IFR VSBYS/CIGS POSSIBLE.
SUN-WED...MOSTLY VFR WITH POTENTIAL FOR IFR FOG RESTRICTIONS EACH
MORNING, ESPECIALLY ELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN/DJP
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...PVN
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
924 PM EDT SUN SEP 7 2014
.SYNOPSIS...
A COLD FRONT WILL STALL JUST OFF THE EASTERN NORTH CAROLINA COAST
TONIGHT. LOW PRESSURE WILL LIFT NORTHEAST ALONG THE STALLED FRONT
MONDAY AND MONDAY NIGHT. THE LOW WILL LIFT NORTHEAST OF THE REGION
TUESDAY WITH THE TRAILING COLD FRONT GRADUALLY DISSIPATING AS IT
DRIFTS OFF THE COAST. OFFSHORE HIGH PRESSURE WILL DOMINATE
WEDNESDAY AND THURSDAY WITH ANOTHER COLD FRONT APPROACHING FROM
THE WEST LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 930 PM SUNDAY...PER SURFACE OBSERVATIONS...FRONTAL BOUNDARY
IS NOW OFF THE COAST AS ALL WINDS ARE NOW NORTHEAST ACROSS THE
CWA. PER CURRENT OBSERVATIONS...HAVE LOWERED MINIMUM TEMPERATURES
BY A COUPLE OF DEGREES ACROSS THE BOARD. LATEST 3 KM HRRR HAS A
GOOD INITIALIZATION OF THE CURRENT PRECIPITATION TRENDS AND HAVE
ACCORDINGLY LOWERED POPS OVER THE SOUTHERN TIER THROUGH MOST OF
THE OVERNIGHT THEN RAMP POPS UP AGAIN TOWARD MORNING AS SURFACE
WAVE OF LOW PRESSURE MOVES ALONG THE FRONT TO OUR SOUTH. WITH THE
AXIS OF HIGHEST PRECIPITABLE WATER (OVER 2 INCHES) NEAR THE
COAST...EXPECT THE NEXT ROUND OF HEAVY RAINFALL TO SET UP IN
SOUTHERN SECTIONS TOWARD MORNING.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
MODEL TRENDS AND CONCENSUS SUGGEST THE BEST CHANCES FOR HEAVIER
PRECIPITATION WILL PUSH WESTWARD ALONG A DEVELOPING WEDGE FRONT ON
MONDAY. WILL CONTINUE CATEGORICAL POPS INLAND AND TAPER BACK
SLIGHTLY TO HIGH LIKELY POPS NEAR THE COAST. THERE WILL BE A
CONTINUED THREAT FOR HEAVY RAIN AND LOCALIZED FLOODING JUST ABOUT
ANYWHERE IN THE FORECAST AREA AND MAY EVENTUALLY NEED TO ISSUE
FLOOD ADVISORIES OR WARNINGS IF HEAVIER/STEADIER RAIN FOCUSES IN
ONE PARTICULAR AREA. HIGHS IN THE UPPER 70S TO LOWER 80S WITH
MAINLY CLOUDY SKIES AND WIDESPREAD PRECIPITATION.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
AS OF 4 PM SUN...AN UNSETTLED/WET PERIOD EXPECTED TO CONTINUE
THROUGH TUE. THE COLD FRONT WILL REMAIN STALLED ACROSS THE AREA
MON NIGHT...WITH AN AREA OF LOW PRESSURE MOVING ALONG THE BOUNDARY
TUES INTO TUES NIGHT. THE STALLED BOUNDARY WILL BE A FOCUS FOR
OCCASIONAL HEAVIER PRECIPITATION WITH GOOD UPPER LEVEL DIVERGENCE
WITH THE REGION LOCATED IN THE RIGHT ENTRANCE OF THE UPPER JET
AND PIECES OF SHORT WAVE ENERGY PUSHING THRU THE LOW AMPLITUDE MID
LEVEL TROF OVER THE EASTERN STATES. MODEL PREFERENCES CONTINUE TO
SIDE WITH A GFE/ECMWF BLEND AS THE NAM CONTINUES TO SHOW A DEEPER
AND FASTER BIAS WITH THE SFC LOW TRACKING ACROSS THE AREA AND AS
SUCH HAVE INCREASED POPS MON NIGHT INTO TUES WITH A SLOWER
DEPARTURE OF THE LOW. FLOODING CONCERNS MAY CONTINUE INTO EARLY
TUES WITH ADDITIONAL RAINFALL AMOUNTS IN THE 1-2 INCH RANGE
POSSIBLE...WITH LOCALIZED HIGHER AMOUNTS POSSIBLE GIVEN THE HIGH
PWATS OF 2 TO 2.25 INCHES. HIGHS WILL BE HELD DOWN BY CLOUDS AND
PRECIP WITH MAX TEMPS UPPER 70S TO LOWER 80S TUE.
THE LOW IS PROGGED TO LIFT NE OF THE REGION TUES NIGHT WITH THE
FRONT FINALLY MOVING OFFSHORE WED...ALLOWING RIDGING/DEEP LAYER
DRYING TO BUILD INTO THE AREA MIDWEEK. ONLY ISOLATED SEA BREEZE
TYPE DIURNAL CONVECTION EXPECTED WED/THU AS SHORT WAVE RIDGE
SUPPRESSES MOST CONVECTION. RISING THICKNESS WILL RESULT IN HIGH
TEMPS MODERATING TO AT OR SLIGHTLY ABOVE NORMAL WED/THU...GENERALLY
HIGHS IN THE LOWER TO UPPER 80S.
ANOTHER COLD FRONT WILL MOVE INTO THE REGION LATE IN THE WEEK BUT
THE USUAL TIMING ISSUES CONTINUE REGARDING THE APPROACH AND
EVENTUAL PASSAGE OF THE FRONT. THERE IS ALMOST A 24 HR DIFFERENCE
BETWEEN THE 12Z GFS AND 12Z ECMWF IN REGARD TO THE TIMING OF THE
FRONT PUSHING SOUTH OF THE AREA LEADING TO BELOW AVERAGE
CONFIDENCE IN THE FORECAST DETAILS LATE IN THE WEEK. PRECIP COULD
BEGIN AS EARLY AS LATE THURS NIGHT WITH BEST CHANCES FRIDAY
AFTERNOON THROUGH SAT...THEN TAPER OFF FROM N TO S SUNDAY.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
SHORT TERM /THROUGH 18Z MONDAY/...
AS OF 630 PM SUNDAY...VARIABLE CONDITIONS ARE EXPECTED AT THE TAF
SITES OVERNIGHT INTO MONDAY IN WIDESPREAD SHOWERS AND A FEW TSTMS.
CURRENTLY...ONLY KPGV REPORTING MVFR CONDITIONS...BUT AS
PRECIPITATION AGAIN APPROACHES FROM THE WEST...EXPECT PERIODS OF
MVFR WITH OCCASIONAL IFR FOR THE REMAINING SITES THROUGH THE
EVENING HOURS INTO OVERNIGHT. AGAIN MONDAY...CONDITIONS WILL BE
VARIABLE BUT MVFR IS LIKELY TO PREDOMINATE GIVEN WIDESPREAD
PRECIPITATION.
LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 4 PM SUN...WIDESPREAD SHOWERS/THUNDERSTORMS WILL BRING
PERIODS OF MVFR AND OCCASIONAL IFR CONDITIONS DURING AN UNSETTLED
WEATHER PERIOD INTO TUE NIGHT AS A SFC FRONT STALLS OVER AND LOW PRES
LIFTS ACROSS REGION. THERE IS A POTENTIAL FOR RADIATION FOG TUE
NIGHT IF SKIES SUFFICIENTLY CLEAR AS LIGHT WINDS WILL PRODUCE A
DECENT FOG SETUP ESPECIALLY WITH A SATURATED GROUND. GRADUAL
DRYING IS EXPECTED WED AND THURS AS HIGH PRES BUILDS INTO THE AREA
WITH PRED VFR CONDITIONS AND ONLY ISOL DIURNALLY DRIVEN
CONVECTION...HOWEVER THERE IS A CHANCE OF MVFR CIGS LINGERING INTO
WED WITH WRAP-AROUND MOISTURE ACROSS THE AREA BEHIND THE DEPARTING
LOW.
&&
.MARINE...
SHORT TERM /TONIGHT/...
AS OF 930 PM SUNDAY...FRONT IS NOW OFF THE SOUTHERN COAST WITH ALL
OF THE NEAR-SHORE BUOYS NOW REPORTING N/NNE WINDS. SPEEDS ARE 15
KNOTS OR LESS AND GENERALLY 5 TO 10 KNOTS OVER ALL BUT THE FAR
NORTHERN SECTIONS. PER LATEST 3 KM HRRR...WINDS SHOULD REMAIN NE/E
THROUGH THE NIGHT WITH SEAS AT 2 TO 4 FEET. THE PRESSURE GRADIENT
WILL TIGHTEN SOUTH OF THE FRONT AS LOW PRESSURE RIDES NE ALONG THE
BNDRY MONDAY AND MAY REACH 15-20 KT MONDAY AFTERNOON OVER
SOUTHERN AND CENTRAL WATERS. SEAS BUILD 3-5 FT IN RESPONSE TO THE
WIND INCREASE.
LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 4 PM SUN...A FRONTAL BOUNDARY WILL REMAIN STALLED ACROSS
EASTERN NC WITH AREA OF LOW PRESSURE SLOWLY LIFTING ALONG THE
FRONT MON NIGHT INTO WED. BELOW NORMAL CONFIDENCE IN THE MARINE
FORECAST AS MODELS NOT IN BEST AGREEMENT WITH TIMING AND
STRENGTH OF THE LOW. PREFERRED MODELS ARE A BLEND OF THE GFS/ECMWF
WHICH IS SLOWER AND WEAKER WITH THE LOW AND THE FORECAST GENERALLY
FOLLOWS THIS TREND WITH WINDS AROUND 10-20 KT. IF THE NAM ENDS UP
VERIFYING WINDS COULD BE SIGNIFICANTLY STRONGER...AND CURRENTLY
SHOWS WINDS AS HIGH AS 20-30 KT AHEAD OF THE LOW MON NIGHT. USED A
BLEND OF THE NWPS AND WAVEWATCH III WITH SEAS PRIMARILY AROUND 3-5
FT...HOWEVER IF THE NAM VERIFIES HIGHER SEAS WILL BE LIKELY. THE
LOW TRACKS OFF THE NC COAST WED WITH WINDS BECOMING LIGHT NW AS
PRESSURE GRADIENT BECOMES WEAK ALONG THE COAST. WINDS GENERALLY
LESS THAN 10KT WILL CONTINUE WED NIGHT INTO EARLY THU...BECOMING
S/SW AGAIN 10-15KT BY LATE THU AFTERNOON AHEAD OF ANOTHER COLD
FRONT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BTC
NEAR TERM...CTC
SHORT TERM...BTC
LONG TERM...BTC/SK
AVIATION...CTC/SK/BM
MARINE...CTC/BTC/SK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
313 PM EDT SAT SEP 6 2014
.SYNOPSIS...
WAVES OF SHOWERS AND A FEW THUNDERSTORMS WITH HEAVY RAINFALL WILL
CONTINUE THROUGH MONDAY AS LOW PRESSURE ALONG THE GEORGIA COAST
LINKS UP WITH A COLD FRONT DIPPING IN FROM THE NORTH. AS THE LOW
EXITS MONDAY NIGHT...A GRADUAL AND WARMING DRYING TREND SHOULD
DEVELOP TUESDAY AND PERSIST INTO LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SATURDAY...ONGOING DIURNAL CONVECTION INLAND WILL LINGER
INTO THE EVENING HOURS BEFORE THE LOSS OF HEATING BRINGS ABOUT ITS
DEMISE. COVERAGE WILL VARY FROM LOW CHANCE TO LIKELY AT TIMES
WITH STORMS HAVING THE ABILITY TO DROP SIGNIFICANT RAINFALL IN A
SHORT PERIOD OF TIME. HOWEVER STORM MOVEMENT IS FAST ENOUGH TO
LIMIT FLOODING POTENTIAL TO TRAINING STORMS. CLOSER TO THE COAST
LINGERING DEBRIS CLOUD FROM THIS MORNINGS CONVECTION HAS SO FAR
INHIBITED HEATING...THUS LIMITING INSTABILITY AND STORM
DEVELOPMENT...ESPECIALLY ACROSS COASTAL NC. ALTHOUGH CLOUD COVER
WILL CONTINUE TO DIMINISH ALONG THE COAST THIS AFTERNOON IT LOOKS
LIKE THERE MAY NOT BE ENOUGH TIME TO GENERATE ENOUGH INSTABILITY
FOR ANYTHING MORE THAN ISOLATED SHOWERS. HAVE BACKED OFF ON POP
FOR THE AFTERNOON HOURS ALONG THE COAST...THOUGH AN ISOLATED
SHOWER OR THUNDERSTORM WILL STILL BE POSSIBLE.
DEEP MOISTURE PLUME WILL SPREAD NORTH INTO THE REGION TONIGHT
PUSHING PRECIPITABLE WATER VALUES OVER 2 INCHES. AT THE SAME TIME
LOW LEVEL JETTING AHEAD OF THE SLOWLY ADVANCING COLD FRONT
INCREASES TO 20 TO 25 KT. LOW LEVEL CONVERGENCE ALONG THE COASTAL
TROUGH COMBINED WITH THE NOCTURNAL JETTING AND THE DEEP MOISTURE
SHOULD PRODUCE OFFSHORE CONVECTION...SOME OF WHICH WILL LIKELY
MOVE ONSHORE OVERNIGHT. NOT CONFIDENT SHOWERS AND THUNDERSTORMS
WILL MOVE FAR INLAND...GIVEN THE LOCATION OF THE TROUGH NEAR THE
COAST AND LIMITED INSTABILITY IN THESE AREAS. WHILE IT IS WEAK FOR
THE FIRST TIME IN SEVERAL DAYS THERE WILL BE SOME UPPER LEVEL
SUPPORT AS FLOW ALOFT BECOMES WEAKLY DIVERGENT. THIS COULD AID
ONGOING STORMS BUT BY ITSELF WOULD PROBABLY NOT BE STRONG ENOUGH
TO GENERATE CONVECTION.
HEAVY RAIN WILL BE POSSIBLE WITH ANY STORMS THAT DO DEVELOP GIVEN
THE DEEP MOISTURE AND FREEZING LEVEL OF 15.6K FT OVERNIGHT. STORM
MOTIONS WILL REMAIN ABOVE 10 KT SO STORM MOTION SHOULD NOT
CONTRIBUTE TO FLOODING BUT TRAINING OR BACK BUILDING STORMS WOULD
HAVE POTENTIAL TO CAUSE LOCALIZED FLOODING GIVEN THE EXPECTED HIGH
PRECIPITATION RATES.
CLOUD COVER AND MOISTURE WILL HELP KEEP LOWS IN THE 70S...BUT ALONG
THE COAST RAINFALL WILL KEEP TEMPS COOLER. COAST SHOULD STILL END
UP WARMEST BUT BY A COUPLE DEGREES AT MOST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...A NON-FRONTAL LOW OVER EASTERN GEORGIA AND
SOUTHERNMOST SOUTH CAROLINA WILL HELP ADVECT IN A RICH TROPICAL
AIRMASS INLAND WITH PRECIPITABLE WATER VALUES 2.0 TO 2.3 INCHES.
OFFSHORE SHOWERS AND T-STORMS SHOULD SWEEP ONSHORE SUNDAY MORNING
ACROSS THE GRAND STRAND AND CAPE FEAR REGION...WITH DAYTIME
HEATING NUDGING THE BEST COVERAGE OF SHOWERS & STORMS INLAND
DURING THE AFTERNOON HOURS. A SYNOPTIC COLD FRONT OVER THE CENTRAL
CAROLINAS WILL SLIP SOUTHEASTWARD INTO THE COASTAL PLAIN SUNDAY
AFTERNOON...INTERCEPTING THE FEED OF TROPICAL MOISTURE AND STALLING
ABOUT HALFWAY BETWEEN I-95 AND THE COAST. THIS IS A GOOD SETUP FOR
SHOWERY WEATHER WITH LOCALIZED HEAVY RAIN...AND FORECAST POPS
SUNDAY RANGE FROM 60-80 PERCENT.
THE SOUTH CAROLINA LOW IS BEING SUSTAINED AT LEAST IN PART BY
CONVECTIVE PROCESSES. THE CYCLONIC SWIRL EXTENDS UP THROUGH 500 MB
WITH A RIDGE PRESENT UP AT 200/300 MB. WHILE THE ODDS FAVOR THIS
SYSTEM NOT INTENSIFYING INTO A NAMED TROPICAL CYCLONE (THE CENTER
IS EXPECTED TO REMAIN INLAND) IT MAY BRING WEATHER REMINISCENT TO
THAT OF A WEAK TROPICAL DEPRESSION. WAVES OF SHOWERS...SOME
HEAVY...WILL CONTINUE TO SWEEP ONSHORE SUNDAY NIGHT INTO MONDAY.
AS THE COLD FRONT REMAINS STALLED ACROSS THE COASTAL PLAIN
MONDAY...THE LOW SHOULD LINK UP WITH THIS BOUNDARY AND BEGIN TO
MOVE NORTHEASTWARD...FINALLY REACHING SOUTHEASTERN NORTH CAROLINA
MONDAY NIGHT AND ACCELERATING OUT TO THE NORTHEAST AFTER MIDNIGHT.
THIS SHOULD SPELL AN END TO THE SHOWERY WEATHER AND SHOULD PUSH
THE FRONT OFF THE COAST.
FROM AN AREAL STANDPOINT WE ARE EXPECTING AS MUCH AS 2.5 INCHES OF
RAIN ALONG THE COAST TONIGHT THROUGH MONDAY NIGHT WITH 1.0 TO 1.7
INCHES NEAR/WEST OF I-95. ISOLATED AREAS COULD REALISTICALLY PICK
UP 5 TO 7 INCHES. THE 12Z NAM WAS AN OUTLIER VERSUS THE GFS/ECMWF
WITH REGARDS TO HOW MUCH THE SURFACE LOW AND ASSOCIATED
WIND/ADVECTION FIELDS INTENSIFY...BUT CANNOT BE RULED OUT. SHOULD
CONFIDENCE GROW THAT EXCESSIVE RAINFALL WILL OCCUR A FLOOD WATCH
MAY BE NEEDED FOR PORTIONS OF COASTAL SOUTH AND NORTH CAROLINA.
DIURNAL TEMPERATURE RANGES WILL BE CONSTRICTED BY ALL THE CLOUDS
AND PRECIPITATION...PARTICULARLY ON MONDAY WHEN A SOLID OVERCAST
MAY PERSIST FOR A GOOD PORTION OF THE DAY WEST OF THE STALLED
FRONT. MOS CONSENSUS TEMPERATURES LOOK REASONABLE -- EXCEPT FOR
HIGHS MONDAY WHERE I HAVE TRIMMED UP TO FIVE DEGREES OFF WEST OF
THE FRONT.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...LOW PRESSURE WILL MOVE UP THE CAROLINA
COAST ALONG A LINGERING COLD FRONT AS WEAK HIGH PRESSURE BUILDS IN
BEHIND IT THROUGH TUESDAY. ANY LINGERING CLOUDS OR SHOWERS TUES
WILL DIMINISH THROUGH LATE TUES INTO WED AS DRY AIR MOVES IN ABOVE
H85. PCP WATER VALUES UP CLOSE TO 2 INCHES EARLY TUES WILL DROP
DOWN TO 1.5 INCHES BY TUES EVE AND EVEN FURTHER BY WED MORNING.
WEAK HIGH PRESSURE WILL REMAIN AT THE SURFACE WHILE RIDGE IN THE
MID TO UPPER LEVELS BUILDS BACK UP THROUGH THE CAROLINAS THROUGH
MID WEEK WITH PLENTY OF DRY AIR AND SUBSIDENCE ALOFT. MAY INCLUDE
A VERY LOW END CHC OF SHWRS ON WED AND THURS BUT OVERALL EXPECT
PLENTY OF SUNSHINE WITH SOME LOCALIZED CU DEVELOPMENT AND POSSIBLY
A STRAY SHWR. BY LATE THURS INTO FRI CHC OF PCP WILL INCREASE AS
RIDGE ALOFT GETS SUPPRESSED FARTHER SOUTH AS A SHORTWAVE BEGINS TO
DIG DOWN AS IT RIDES ACROSS THE GREAT LAKES. THIS SHORTWAVE WILL
PUSH A COLD FRONT INTO THE CAROLINAS BY FRI INTO SATURDAY WITH
MORE WIDESPREAD SHWR AND TSTMS EXPECTED HEADING INTO THE WEEKEND.
TEMPS NEAR NORMAL ON TUES IN LINGERING CLOUDS AND SHWRS WILL WARM UP
AGAIN THROUGH MID WEEK AS H5 HEIGHTS RISE WITH BUILDING RIDGE.
EXPECT TEMPS IN THE MID 80S ON TUES WILL BE BACK UP AROUND 90 OR SO
BY THURS AND FRI. BY SATURDAY CLOUDS AND SHWRS ASSOCIATED WITH COLD
FRONT WILL KEEP TEMPS IN THE 80S.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...THE HEAVIEST ACTIVITY SEEMS TO BE OVER...FOR NOW. LOOK
FOR CONVECTION DEVELOPING MAINLY INLAND THIS AFTERNOON. THE HRRR IS
NOT TOO IMPRESSED...WITH ONLY LIGHT SCATTERED ACTIVITY THIS
AFTERNOON. WILL STAY WITH MAINLY VCSH INLAND WITH A TEMPO GROUP
ALONG THE COAST. TONIGHT...DEEP MOISTURE WILL BE ON THE INCREASE
WITH ONSHORE FLOW AND AN INVERTED TROUGH DEVELOPING. LOOK FOR SOME
GOOD HEAVY NOCTURNAL SHOWERS MAINLY AFTER 06Z WITH SOME MVFR/IFR
CONDITIONS. THE WORST CASE CEILINGS WILL PROBABLY BE INLAND...WITH
IFR EXPECT OVERNIGHT THROUGH MID MORNING. MAINLY LIGHT SOUTHERLY
FLOW THROUGH THE PERIOD.
EXTENDED OUTLOOK...INCLEMENT WEATHER WILL CONTINUE SUNDAY NIGHT AND
MONDAY WITH INTERMITTENT IFR CONDITIONS EXPECTED. IMPROVING
CONDITIONS TUESDAY AND WEDNESDAY. SLIGHT CHANCE FOR SHOWERS THURSDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SATURDAY...ALTHOUGH GRADIENT WILL CHANGE LITTLE
OVERNIGHT THE STRENGTHENING LOW LEVEL JET WILL RESULT IN SLIGHTLY
HIGHER WIND SPEEDS THAN PREVIOUS NIGHTS. SOUTH TO SOUTHWEST FLOW
WILL HANG IN THE 10 TO 15 KT RANGE WITH POTENTIAL FOR THE
OCCASIONAL GUST EXCEEDING 15 KT. SEAS WILL CONTINUE 2 TO 3 FT
OVERNIGHT BUT WITH SOME ISOLATED 4 FT THROWN IN DUE TO PROLONGED
SOUTHERLY FETCH AND THE SLIGHT INCREASE IN SPEEDS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...A COLD FRONT OVER THE CENTRAL CAROLINAS
SUNDAY MORNING WILL SAG INTO THE COASTAL PLAIN BY AFTERNOON...
STALLING AS IT ENCOUNTERS AN AREA OF LOW PRESSURE OVER
SOUTHERNMOST SOUTH CAROLINA. THIS LOW IS BEING MAINTAINED (AT
LEAST IN PART) BY SHOWER AND THUNDERSTORM ACTIVITY ONGOING AROUND
IT. WHILE THE ODDS DO NOT FAVOR THE DEVELOPMENT OF A NAMED
TROPICAL SYSTEM...THIS SITUATION WILL HAVE SOME PARALLELS TO WHAT
WE MIGHT EXPERIENCE DURING A WEAK TROPICAL DEPRESSION. THE LOW
OVER SOUTH CAROLINA WILL LIFT SLOWLY NORTHEASTWARD ALONG THE FRONT
SUNDAY NIGHT AND MONDAY...REACHING SOUTHEASTERN NORTH CAROLINA
MONDAY NIGHT. THIS MEANS WE`LL HAVE AN EXTENDED PERIOD OF HEAVY
SHOWERS AND MODERATE SOUTH WINDS SUNDAY THROUGH MONDAY EVENING...
WITH WINDS VEERING MORE WESTERLY LATE MONDAY NIGHT AS THE LOW
ACCELERATES NORTHEASTWARD THROUGH EASTERN NORTH CAROLINA.
AT THIS TIME THE HIGHEST WINDS WE ARE EXPECTING ARE 15-20 KNOTS
WITH GUSTS IN THE LOWER 20S. THIS IS OF COURSE VERY DEPENDENT ON
HOW MUCH (IF ANY) STRENGTHENING OCCURS OF THE SYSTEM BEYOND THE
WEAK FRONTAL LOW NOW EXPECTED. ASSUMING THESE WINDS PAN OUT SEAS
SHOULD BUILD TO 4-5 FEET AWAY FROM SHORE...HIGHEST SUNDAY NIGHT
INTO MONDAY MORNING ACROSS THE WATERS SOUTH OF CAPE FEAR.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 300 PM SATURDAY...LOW PRESSURE ALONG LINGERING FRONT ALONG THE
CAROLINA COAST EARLY TUES WILL LIFT OFF TO THE NORTHEAST THROUGH THE
DAY. THIS MAY CAUSE VARIABLE WINDS OVER THE COASTAL WATERS ON TUES
BUT OVERALL SHOULD SEE SW-W WINDS BECOMING NORTHERLY AND LIGHTEN
THROUGH EARLY WED. WEAK HIGH PRESSURE OVER THE WATERS WILL MAINTAIN
LIGHT AND VARIABLE WINDS COMING AROUND TO THE SOUTH BY THURS BUT
REMAINING 10 KTS OR LESS. THE OFF SHORE WINDS WILL KNOCK SEAS DOWN
THROUGH TUES FROM 2 TO 4 FT EARLY DOWN TO 3 FT OR LESS TUES NIGHT
THROUGH THURS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TRA
NEAR TERM...III
SHORT TERM...TRA
LONG TERM...RGZ
AVIATION...HDL/III
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
215 PM EDT SAT SEP 6 2014
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO INCREASE IN COVERAGE
TODAY AS A COLD FRONT APPROACHES. LOW PRESSURE MAY ENHANCE THE
RAINFALL SUNDAY AND MONDAY. A GRADUAL DRYING TREND WILL GET UNDERWAY
ON TUESDAY AND PERSIST INTO LATE NEXT WEEK WHILE AFTERNOON HIGHS
CLIMB.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SATURDAY...ONGOING DIURNAL CONVECTION INLAND WILL LINGER
INTO THE EVENING HOURS BEFORE THE LOSS OF HEATING BRINGS ABOUT ITS
DEMISE. COVERAGE WILL VARY FROM LOW CHANCE TO LIKELY AT TIMES
WITH STORMS HAVING THE ABILITY TO DROP SIGNIFICANT RAINFALL IN A
SHORT PERIOD OF TIME. HOWEVER STORM MOVEMENT IS FAST ENOUGH TO
LIMIT FLOODING POTENTIAL TO TRAINING STORMS. CLOSER TO THE COAST
LINGERING DEBRIS CLOUD FROM THIS MORNINGS CONVECTION HAS SO FAR
INHIBITED HEATING...THUS LIMITING INSTABILITY AND STORM
DEVELOPMENT...ESPECIALLY ACROSS COASTAL NC. ALTHOUGH CLOUD COVER
WILL CONTINUE TO DIMINISH ALONG THE COAST THIS AFTERNOON IT LOOKS
LIKE THERE MAY NOT BE ENOUGH TIME TO GENERATE ENOUGH INSTABILITY
FOR ANYTHING MORE THAN ISOLATED SHOWERS. HAVE BACKED OFF ON POP
FOR THE AFTERNOON HOURS ALONG THE COAST...THOUGH AN ISOLATED
SHOWER OR THUNDERSTORM WILL STILL BE POSSIBLE.
DEEP MOISTURE PLUME WILL SPREAD NORTH INTO THE REGION TONIGHT
PUSHING PRECIPITABLE WATER VALUES OVER 2 INCHES. AT THE SAME TIME
LOW LEVEL JETTING AHEAD OF THE SLOWLY ADVANCING COLD FRONT
INCREASES TO 20 TO 25 KT. LOW LEVEL CONVERGENCE ALONG THE COASTAL
TROUGH COMBINED WITH THE NOCTURNAL JETTING AND THE DEEP MOISTURE
SHOULD PRODUCE OFFSHORE CONVECTION...SOME OF WHICH WILL LIKELY
MOVE ONSHORE OVERNIGHT. NOT CONFIDENT SHOWERS AND THUNDERSTORMS
WILL MOVE FAR INLAND...GIVEN THE LOCATION OF THE TROUGH NEAR THE
COAST AND LIMITED INSTABILITY IN THESE AREAS. WHILE IT IS WEAK FOR
THE FIRST TIME IN SEVERAL DAYS THERE WILL BE SOME UPPER LEVEL
SUPPORT AS FLOW ALOFT BECOMES WEAKLY DIVERGENT. THIS COULD AID
ONGOING STORMS BUT BY ITSELF WOULD PROBABLY NOT BE STRONG ENOUGH
TO GENERATE CONVECTION.
HEAVY RAIN WILL BE POSSIBLE WITH ANY STORMS THAT DO DEVELOP GIVEN
THE DEEP MOISTURE AND FREEZING LEVEL OF 15.6K FT OVERNIGHT. STORM
MOTIONS WILL REMAIN ABOVE 10 KT SO STORM MOTION SHOULD NOT
CONTRIBUTE TO FLOODING BUT TRAINING OR BACK BUILDING STORMS WOULD
HAVE POTENTIAL TO CAUSE LOCALIZED FLOODING GIVEN THE EXPECTED HIGH
PRECIPITATION RATES.
CLOUD COVER AND MOISTURE WILL HELP KEEP LOWS IN THE 70S...BUT ALONG
THE COAST RAINFALL WILL KEEP TEMPS COOLER. COAST SHOULD STILL END
UP WARMEST BUT BY A COUPLE DEGREES AT MOST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...VERY ACTIVE WEATHER IS EXPECTED THROUGH THE
SHORT TERM PERIOD WITH POTENTIAL FOR SOME HEAVY RAINFALL. THERE IS
JUST ENOUGH VARIATION IN MODEL SOLUTIONS TO SAY FOR SURE WHEN THE
BEST WINDOW OF OPPORTUNITY FOR THAT WILL BE. PIEDMONT TROUGH NEARLY
LINKED WITH NORTHWARD EXTENSION OF CARIBBEAN TROPICAL WAVE EXTENDED
JUST WEST OF FL RIGHT NOW. THROUGH SUNDAY THIS MOISTURE IS PROGGED
TO ADVECT NORTH AND EASTWARD...SURGING INTO THE COASTAL CAROLINAS.
MULTIPLE SOURCES OF LIFT INCLUDE BUT ARE NOT LIMITED TO THE SEA
BREEZE, THE PIEDMONT TROUGH, AND PVA ASSOC WITH THE MID LEVEL SYSTEM
MOVING NE UP THE COAST. A COLD FRONT WILL ALSO BE APPROACHING FROM
THE NORTH TO PROVIDE A SQUEEZE PLAY FOR THIS MOISTURE TRYING TO MOVE
NORTHWARD. WHERE THIS ZONE OF SURFACE-BASED OVERRUNNING SETS UP
LIKELY STANDS TO SEE THE HEAVIEST RAINFALL ON SUNDAY. WRF IS A BIT
NORTH OF THE REGION WHEREAS THE GFS TAKES AIM AT MOST OF THE COASTAL
CAROLINAS. THE LATTER HALF OF THE PERIOD GETS TRICKY. THE GFS WOULD
IMPLY THAT COPIOUS RAINS CONTINUE THROUGH ABOUT MONDAY MORNING.
THEREAFTER THE SURFACE REFLECTION OF THE FL UPPER LOW MOVES NE ALONG
THE FRONT AS A FAIRLY FLAT WAVE. THE WRF WHICH WAS INITIALLY A
STRONG OUTLIER CONTINUES TO SHOW A SIMILAR SCENARIO. ITS MORE CLOSED
OFF LOW IS SLOWER TO ZIPPER ITS WAY UP THE FRONT...BUT IT JUST SEEMS
TO BE IMPLYING TOO MUCH BAROTROPIC/LATENT HEATING DRIVEN
STRENGTHENING PROCESSES TAKING PLACE...ALL WHILE THE LOW REMAINS
OVER LAND. ANY OF THOSE PROCESSES MAY VERY WELL TAKE PLACE BUT
PROBABLY WELL AFTER IT HAS PASSED NORTH OF HATTERAS A LA THE
CANADIAN GEM MODEL. THE ECMWF IS A RATHER NICE COMPROMISE SHOWING
THAT MUCH OF MONDAY IS JUST AS WET FOR MOST AREAS AS SUNDAY...WHICH
PERHAPS A MORE DEFINED COASTAL VS INLAND GRADIENT IN QPF...BOTH DAYS
WETTEST ALONG THE COAST.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 AM SATURDAY...LOW LEVEL MOISTURE ASSOCIATED WITH
DISSIPATING FRONT SHOULD LINGER FOR LOW END CHANCE POPS ESPECIALLY
ALONG THE COAST. MID LEVEL ZONAL FLOW WILL BE DRYING OUT MUCH OF THE
COLUMN ABOVE THE BOUNDARY LAYER THOUGH. WEDNESDAY LOOKS LIKE A
TRANSITION BACK TO A WARM SEASON PATTERN WITH FLAT WEAK RIDGING
ACROSS NRN GOMEX AND SRN U.S. WHILE BERMUDA HIGH STRUGGLES TO
REASSERT ITSELF. THE LATTER FACT NOT THAT GREAT FOR DIURNAL
CONVECTION-INDUCING LOW LEVEL MOISTURE ADVECTION BUT SOME FRONTAL
MOISTURE MAY STILL LINGER. ISO POPS AND CLIMO TEMPS APPEAR A GOOD
BET. THE MID LEVEL RIDGE INCREASES IN AMPLITUDE ON THURSDAY BRINGING
A WARMER AFTERNOON WHILE INCREASING TROUGINESS OVER THE NRN PLAINS
DRIVES A STRONG FRONT INTO THE GREAT LAKES. PREFRONTAL TROUGH
DEVELOPS ACRS THE PIEDMONT ON FRIDAY WITH A LITTLE EXTRA MOISTURE
FLUX INTO THE COASTAL PLAIN AS A RESULT.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...THE HEAVIEST ACTIVITY SEEMS TO BE OVER...FOR NOW. LOOK
FOR CONVECTION DEVELOPING MAINLY INLAND THIS AFTERNOON. THE HRRR IS
NOT TOO IMPRESSED...WITH ONLY LIGHT SCATTERED ACTIVITY THIS
AFTERNOON. WILL STAY WITH MAINLY VCSH INLAND WITH A TEMPO GROUP
ALONG THE COAST. TONIGHT...DEEP MOISTURE WILL BE ON THE INCREASE
WITH ONSHORE FLOW AND AN INVERTED TROUGH DEVELOPING. LOOK FOR SOME
GOOD HEAVY NOCTURNAL SHOWERS MAINLY AFTER 06Z WITH SOME MVFR/IFR
CONDITIONS. THE WORST CASE CEILINGS WILL PROBABLY BE INLAND...WITH
IFR EXPECT OVERNIGHT THROUGH MID MORNING. MAINLY LIGHT SOUTHERLY
FLOW THROUGH THE PERIOD.
EXTENDED OUTLOOK...INCLEMENT WEATHER WILL CONTINUE SUNDAY NIGHT AND
MONDAY WITH INTERMITTENT IFR CONDITIONS EXPECTED. IMPROVING
CONDITIONS TUESDAY AND WEDNESDAY. SLIGHT CHANCE FOR SHOWERS THURSDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SATURDAY...ALTHOUGH GRADIENT WILL CHANGE LITTLE
OVERNIGHT THE STRENGTHENING LOW LEVEL JET WILL RESULT IN SLIGHTLY
HIGHER WIND SPEEDS THAN PREVIOUS NIGHTS. SOUTH TO SOUTHWEST FLOW
WILL HANG IN THE 10 TO 15 KT RANGE WITH POTENTIAL FOR THE
OCCASIONAL GUST EXCEEDING 15 KT. SEAS WILL CONTINUE 2 TO 3 FT
OVERNIGHT BUT WITH SOME ISOLATED 4 FT THROWN IN DUE TO PROLONGED
SOUTHERLY FETCH AND THE SLIGHT INCREASE IN SPEEDS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...SWRLY GRADIENT WINDS WILL STILL BE QUITE
`SEASONABLE` DESPITE COLD FRONT PUSHING INTO THE CAROLINAS. THE
TEMPORAL PERSISTENCE OF THE FETCH HOWEVER MAY CAUSE THE OCCASIONAL 5
FT WAVE TO APPEAR ALONG OUTER EDGES OF NRN LEGS. HOW THE REMAINDER
OF THE PERIOD UNFOLDS IS RATHER UNCERTAIN AS IT WILL INVOLVE LOW
PRESSURE TRAVELING NORTH AND EAST ALONG THE STALLED FRONTAL
BOUNDARY. SOME GUIDANCE IS PROBLEMATICALLY DEVELOPING A STRONG LOW
THAT LOOKS LIKE IT IS BORNE OF TROPICAL STRENGTHENING DESPITE THE
LOW REMAINING OVER LAND. THE SLOWER AND WEAKER MODELS ARE THUS
PREFERRED AND EVEN THIS MAY PUSH WIND OR SEAS CLOSE TO BUT GENERALLY
SHY OF SCEC CRITERIA. FUTURE MODEL RUNS SHOULD CLARIFY THESE
UNCERTAINTIES.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 300 AM SATURDAY...THE DEPARTURE OF THE SURFACE LOW OF THE
SHORT TERM AND THE APPARENT RAPID WEAKENING OF ITS ASSOCIATED
FRONTAL BOUNDARY AND TUESDAY WINDS AND SEAS MAY FALL TO QUITE
MINIMAL LEVELS WITH A GENERALLY OFFSHORE FLOW DIRECTION. A CONTINUED
WEAKENING OF THE BOUNDARY ON WEDNESDAY SHOULD ALLOW FOR A GRADUAL
TURN TO THE SOUTH WHILE WIND AND SEAS REMAIN MINIMAL.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...III
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
425 PM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL CONTINUE MOVING THROUGH THE AREA TODAY. DRIER
HIGH PRESSURE WILL BUILD IN FOR SUNDAY AND MONDAY...BEFORE WARMER
AND MORE HUMID CONDITIONS RETURN ON TUESDAY AND WEDNESDAY. CHANCES
FOR SHOWERS AND THUNDERSTORMS WILL INCREASE BY THE MIDDLE OF THE
WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A CURRENT WIND ANALYSIS AT THE SURFACE SHOWS THAT THE COLD FRONT
HAS CROSSED THROUGH THE VAST MAJORITY OF THE CWA...WITH NORTHWEST
WINDS NOW REPORTED AT PORTSMOUTH AND FLEMING-MASON AIRPORTS. THE
AIR MASS CHANGE WILL CONTINUE FOR THE NEXT SEVERAL HOURS...AS
TEMPERATURES AND DEWPOINTS ARE STILL MUCH HIGHER IN THE
SOUTHEASTERN CWA. NORTH OF THE BROKEN BAND OF LIGHT
SHOWERS ACROSS THE HEART OF THE CWA...TEMPERATURES ARE ALREADY
FALLING INTO THE UPPER 60S...WITH DEWPOINTS IN THE LOWER TO MID
60S.
WITH LAPS ANALYSIS INDICATING SURFACE-BASED INSTABILITY OF AROUND
1000-1500 J/KG IN THE FAR SOUTHERN CWA...THERE STILL REMAINS A
BRIEF CHANCE FOR THUNDER. HOWEVER...THE COLD ADVECTION WILL BRING
THIS INSTABILITY TO AN END BY AROUND 21Z...WITH ONLY SHOWERS
EXPECTED AFTER THAT. HRRR TRENDS INDICATE THAT THE SHOWERS OVER
THE REST OF THE CWA WILL CONTINUE A DIMINISHING TREND THIS
AFTERNOON AND EVENING...AND THE ENTIRE CWA WILL LIKELY BE DRY BY
MIDNIGHT. SKIES ARE ALSO EXPECTED TO CLEAR...BUT THE FALLING
DEWPOINTS WILL MAKE FOG UNLIKELY. THESE DRIER CONDITIONS MAY LEAD
TO A BIG CHANGE IN MIN TEMPS FROM LAST NIGHT...WITH OUTLYING AREAS
IN THE NORTHERN HALF OF THE CWA GETTING AS LOW AS 50 DEGREES
TONIGHT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
SPRAWLING HIGH PRESSURE WILL BE CENTERED OVER THE NORTHERN OHIO
VALLEY ON SUNDAY MORNING...WITH A TREND TOWARD GRADUALLY DRIFTING
EASTWARD THROUGH MONDAY MORNING. THE DRY AIR MASS WILL KEEP
SIGNIFICANT MOISTURE SOUTH OF THE ILN CWA...LIMITING CLOUDS TO
JUST A FEW CUMULUS. TEMPERATURES WILL STRUGGLE TO REACH NORMAL
VALUES...AND THE GOING FORECAST FOR MAX TEMPS ON SUNDAY IS A FEW
DEGREES BELOW CLIMATOLOGY.
BY MONDAY MORNING...THE MAIN AXIS OF THE SURFACE HIGH WILL EXTEND
FROM UPSTATE NEW YORK THROUGH MISSOURI. AN AREA OF SURFACE
TROUGHING IS FORECAST TO DEVELOP ON THE WEST SIDE OF THE
APPALACHIANS...AS A WEAK SHORTWAVE ALSO PASSES EASTWARD INTO THE
OHIO VALLEY. THOUGH SIGNIFICANT MOISTURE ASSOCIATED WITH A SURFACE
LOW WILL AFFECT THE ATLANTIC COAST FROM FLORIDA THROUGH
DELAWARE...VERY LITTLE OF THE MOISTURE WILL BE DRAWN AS FAR WEST
AS THE ILN CWA. THIS FEATURE WARRANTS ONLY A 20-POP GIVEN CURRENT
MODEL PROJECTIONS.
FORECAST MAX TEMPERATURES FOR MONDAY ARE VERY CLOSE TO
CLIMATOLOGY. WITH A SLIGHT INCREASE IN WARM ADVECTION BEGINNING ON
MONDAY NIGHT...MIN TEMPS GOING INTO TUESDAY MORNING REPRESENT AN
INCREASE FROM BOTH SATURDAY AND SUNDAY NIGHTS.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
THE OPERATIONAL MODELS ARE IN FAIRLY GOOD AGREEMENT FOR THE LONG
TERM PERIOD IN TERMS OF LARGE SCALE SYNOPTIC SYSTEMS. THERE ARE THE
USUAL STRENGTH AND TIMING ISSUES. AS SUCH...HAVE LEANED ON A BLEND
OF THE 12Z ECMWF...12Z GFS AND WPC GUIDANCE.
ON TUESDAY...REGION WILL BE UNDER A ZONAL FLOW ALOFT. MODELS
INDICATE THAT THERE SHOULD BE A DRY WEDGE IN TERMS OF DEEP MOISTURE
AND A LACK OF INSTABILITY...SO HAVE KEPT THE FORECAST DRY DESPITE
WEAK EMBEDDED DISTURBANCES WITHIN THE FLOW. SKIES WILL RANGE FROM
MOSTLY SUNNY TO PARTLY CLOUDY. HIGHS WILL RANGE FROM THE THE LOWER
TO MID 80S.
THE UPR LVL FLOW PATTERN WILL UNDERGO AMPLIFICATION THROUGH THE
REMAINDER OF THE LONG TERM PERIOD. ENERGY FROM OFF THE CA COAST WILL
EJECT QUICKLY NE INTO THE PLAINS AND THEN TO THE WESTERN GREAT LAKES
LATE TUESDAY NIGHT INTO WEDNESDAY. THIS ENERGY WILL TRY TO PHASE
WITH ENERGY DIGGING FROM WESTERN CANADA INTO THE NORTHERN PLAINS
WEDNESDAY INTO THURSDAY. THIS SCENARIO WILL ALLOW A LOW PRESSURE
SYSTEM TO DEEPEN AS IT MOVES NORTHEAST THROUGH THE WESTERN GREAT
LAKES INTO SE CANADA DURING THIS PERIOD...SENDING AN ATTENDANT COLD
FRONT SOUTHEAST THROUGH OUR REGION. CURRENT FORECASTS SUGGEST THAT A
STRONG LOW LEVEL JET AND WAA PCPN WILL BREAK OUT TO OUR WEST AND
LIKELY SKIM OUR NW CWFA ON WEDNESDAY WITH THE REMAINDER OF THE
REGION SEEING A CHANCE OF PCPN WITH AN ADVANCING WARM FRONT. THE
BEST THREAT FOR THE ENTIRE REGION TO SEE PCPN WILL COME WEDNESDAY
NIGHT INTO THURSDAY MORNING AS THE COLD FRONT SWINGS SOUTHEAST. THIS
WILL BE A DYNAMIC SYSTEM WITH DECENT WIND ENERGY AND LOW LEVEL
FRONTAL CONVERGENCE. AS SUCH...THE POTENTIAL FOR THUNDERSTORMS TO BE
SEVERE WEDNESDAY NIGHT INTO THURSDAY MORNING WILL DEPEND ON THE
DEGREE OF INSTABILITY...ALTHOUGH WITH WINDS OF LOWER 40 KNOTS AT 925
MB AND LOWER TO MID 50 KNOTS AT 850 MB...IT MAY NOT TAKE A WHOLE
LOT. SPC HAS HIGHLIGHTED THE GREAT LAKES REGION/PARTS OF THE OHIO
VALLEY IN A DAY 5 30 PERCENT RISK FOR SEVERE STORMS. WILL
HIGHLIGHT THIS THREAT IN THE HWO...BUT WILL BROAD BRUSH IT AT THIS
POINT IN TIME. COLD FRONT SHOULD PUSH SOUTHEAST AWAY FROM THE AREA
ON THURSDAY WITH PCPN PUSHING OUT AS WELL.
FOR THE PERIOD THURSDAY NIGHT INTO SATURDAY...A PRETTY DECENT MID
LEVEL CLOSED LOW WILL TRAVERSE EAST/NORTHEAST THROUGH THE GREAT
LAKES AND SOUTHEAST CANADA THROUGH THE PERIOD. THIS WILL EVENTUALLY
ALLOW AN EXPANSIVE AREA OF SURFACE HIGH PRESSURE TO BUILD INTO THE
REGION BY SATURDAY. ANY SPOTTY SHOWER ACTIVITY APPEARS TO BE
RELEGATED CLOSER TO THE GREAT LAKES ON FRIDAY SO HAVE LEFT THE
FORECAST DRY. TEMPERATURES WILL SHOW A SUBSTANTIAL COOL DOWN FROM
HIGHS IN THE 70S AND 80S ON WEDNESDAY. HIGHS BY THE WEEKEND WILL BE
MAINLY IN THE 60S WITH LOWS DIPPING INTO THE 40S. THESE VALUES WILL
BE SOME 10 TO 15 DEGREES BELOW NORMAL FOR EARLY SEPTEMBER.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
STRATUS DECK NORTHWEST OF THE COLD FROPA THIS AFTERNOON WILL BE
IFR AT FIRST AND THEN LIFT TO MVFR WITH AN INCREASED CHANCE FOR
SOME PASSING SHOWERS.
ACTIVITY WILL MOVE SOUTHEAST THROUGH THE DAY AND WITH DAYTIME
HEATING SOME THUNDERSTORMS MAY BEGIN TO POP...GENERALLY SOUTHEAST
OF I-71 CORRIDOR AND AWAY FROM TAF SITES.
CLOUD COVER WILL LIFT AND DISPERSE LATER TODAY UNDER A DRYING
NORTH WIND. SKIES WILL CLEAR TONIGHT THOUGH ENOUGH LOW LEVEL
MOISTURE MAY BE PRESENT FOR SOME PASSING SC AND DAYBREAK MVFR
VSBYS IN FOG. ANY SC TONIGHT IS NOT EXPECTED TO BE EXPANSIVE OR
UNIFORM ENOUGH TO MAKE A CIG.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
414 PM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL CONTINUE MOVING THROUGH THE AREA TODAY. DRIER
HIGH PRESSURE WILL BUILD IN FOR SUNDAY AND MONDAY...BEFORE WARMER
AND MORE HUMID CONDITIONS RETURN ON TUESDAY AND WEDNESDAY. CHANCES
FOR SHOWERS AND THUNDERSTORMS WILL INCREASE BY THE MIDDLE OF THE
WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A CURRENT WIND ANALYSIS AT THE SURFACE SHOWS THAT THE COLD FRONT
HAS CROSSED THROUGH THE VAST MAJORITY OF THE CWA...WITH NORTHWEST
WINDS NOW REPORTED AT PORTSMOUTH AND FLEMING-MASON AIRPORTS. THE
AIR MASS CHANGE WILL CONTINUE FOR THE NEXT SEVERAL HOURS...AS
TEMPERATURES AND DEWPOINTS ARE STILL MUCH HIGHER IN THE
SOUTHEASTERN CWA. NORTH OF THE BROKEN BAND OF LIGHT
SHOWERS ACROSS THE HEART OF THE CWA...TEMPERATURES ARE ALREADY
FALLING INTO THE UPPER 60S...WITH DEWPOINTS IN THE LOWER TO MID
60S.
WITH LAPS ANALYSIS INDICATING SURFACE-BASED INSTABILITY OF AROUND
1000-1500 J/KG IN THE FAR SOUTHERN CWA...THERE STILL REMAINS A
BRIEF CHANCE FOR THUNDER. HOWEVER...THE COLD ADVECTION WILL BRING
THIS INSTABILITY TO AN END BY AROUND 21Z...WITH ONLY SHOWERS
EXPECTED AFTER THAT. HRRR TRENDS INDICATE THAT THE SHOWERS OVER
THE REST OF THE CWA WILL CONTINUE A DIMINISHING TREND THIS
AFTERNOON AND EVENING...AND THE ENTIRE CWA WILL LIKELY BE DRY BY
MIDNIGHT. SKIES ARE ALSO EXPECTED TO CLEAR...BUT THE FALLING
DEWPOINTS WILL MAKE FOG UNLIKELY. THESE DRIER CONDITIONS MAY LEAD
TO A BIG CHANGE IN MIN TEMPS FROM LAST NIGHT...WITH OUTLYING AREAS
IN THE NORTHERN HALF OF THE CWA GETTING AS LOW AS 50 DEGREES
TONIGHT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
SPRAWLING HIGH PRESSURE WILL BE CENTERED OVER THE NORTHERN OHIO
VALLEY ON SUNDAY MORNING...WITH A TREND TOWARD GRADUALLY DRIFTING
EASTWARD THROUGH MONDAY MORNING. THE DRY AIR MASS WILL KEEP
SIGNIFICANT MOISTURE SOUTH OF THE ILN CWA...LIMITING CLOUDS TO
JUST A FEW CUMULUS. TEMPERATURES WILL STRUGGLE TO REACH NORMAL
VALUES...AND THE GOING FORECAST FOR MAX TEMPS ON SUNDAY IS A FEW
DEGREES BELOW CLIMATOLOGY.
BY MONDAY MORNING...THE MAIN AXIS OF THE SURFACE HIGH WILL EXTEND
FROM UPSTATE NEW YORK THROUGH MISSOURI. AN AREA OF SURFACE
TROUGHING IS FORECAST TO DEVELOP ON THE WEST SIDE OF THE
APPALACHIANS...AS A WEAK SHORTWAVE ALSO PASSES EASTWARD INTO THE
OHIO VALLEY. THOUGH SIGNIFICANT MOISTURE ASSOCIATED WITH A SURFACE
LOW WILL AFFECT THE ATLANTIC COAST FROM FLORIDA THROUGH
DELAWARE...VERY LITTLE OF THE MOISTURE WILL BE DRAWN AS FAR WEST
AS THE ILN CWA. THIS FEATURE WARRANTS ONLY A 20-POP GIVEN CURRENT
MODEL PROJECTIONS.
FORECAST MAX TEMPERATURES FOR MONDAY ARE VERY CLOSE TO
CLIMATOLOGY. WITH A SLIGHT INCREASE IN WARM ADVECTION BEGINNING ON
MONDAY NIGHT...MIN TEMPS GOING INTO TUESDAY MORNING REPRESENT AN
INCREASE FROM BOTH SATURDAY AND SUNDAY NIGHTS.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
THE OPERATIONAL MODELS ARE IN FAIRLY GOOD AGREEMENT FOR THE LONG
TERM PERIOD IN TERMS OF LARGE SCALE SYNOPTIC SYSTEMS. THERE ARE THE
USUAL STRENGTH AND TIMING ISSUES. AS SUCH...HAVE LEANED ON A BLEND
OF THE 12Z ECMWF...12Z GFS AND WPC GUIDANCE.
ON TUESDAY...REGION WILL BE UNDER A ZONAL FLOW ALOFT. MODELS
INDICATE THAT THERE SHOULD BE A DRY WEDGE IN TERMS OF DEEP MOISTURE
AND A LACK OF INSTABILITY...SO HAVE KEPT THE FORECAST DRY DESPITE
WEAK EMBEDDED DISTURBANCES WITHIN THE FLOW. SKIES WILL RANGE FROM
MOSTLY SUNNY TO PARTLY CLOUDY. HIGHS WILL RANGE FROM THE THE LOWER
TO MID 80S.
THE UPR LVL FLOW PATTERN WILL UNDERGO AMPLIFICATION THROUGH THE
REMAINDER OF THE LONG TERM PERIOD. ENERGY FROM OFF THE CA COAST WILL
EJECT QUICKLY NE INTO THE PLAINS AND THEN TO THE WESTERN GREAT LAKES
LATE TUESDAY NIGHT INTO WEDNESDAY. THIS ENERGY WILL TRY TO PHASE
WITH ENERGY DIGGING FROM WESTERN CANADA INTO THE NORTHERN PLAINS
WEDNESDAY INTO THURSDAY. THIS SCENARIO WILL ALLOW A LOW PRESSURE
SYSTEM TO DEEPEN AS IT MOVES NORTHEAST THROUGH THE WESTERN GREAT
LAKES INTO SE CANADA DURING THIS PERIOD...SENDING AN ATTENDANT COLD
FRONT SOUTHEAST THROUGH OUR REGION. CURRENT FORECASTS SUGGEST THAT A
STRONG LOW LEVEL JET AND WAA PCPN WILL BREAK OUT TO OUR WEST AND
LIKELY SKIM OUR NW CWFA ON WEDNESDAY WITH THE REMAINDER OF THE
REGION SEEING A CHANCE OF PCPN WITH AN ADVANCING WARM FRONT. THE
BEST THREAT FOR THE ENTIRE REGION TO SEE PCPN WILL COME WEDNESDAY
NIGHT INTO THURSDAY MORNING AS THE COLD FRONT SWINGS SOUTHEAST. THIS
WILL BE A DYNAMIC SYSTEM WITH DECENT WIND ENERGY AND LOW LEVEL
FRONTAL CONVERGENCE. AS SUCH...THE POTENTIAL FOR THUNDERSTORMS TO BE
SEVERE WEDNESDAY NIGHT INTO THURSDAY MORNING WILL DEPEND ON THE
DEGREE OF INSTABILITY...ALTHOUGH WITH WINDS OF LOWER 40 KNOTS AT 925
MB AND LOWER TO MID 50 KNOTS AT 850 MB...IT MAY NOT TAKE A WHOLE
LOT. SPC HAS HIGHLIGHTED THE GREAT LAKES REGION/PARTS OF THE OHIO
VALLEY IN A DAY 4 30 PERCENT RISK FOR SEVERE STORMS. WILL HIGHLIGHT
THIS THREAT IN THE HWO...BUT WILL BROAD BRUSH IT AT THIS POINT IN
TIME. COLD FRONT SHOULD PUSH SOUTHEAST AWAY FROM THE AREA ON
THURSDAY WITH PCPN PUSHING OUT AS WELL.
FOR THE PERIOD THURSDAY NIGHT INTO SATURDAY...A PRETTY DECENT MID
LEVEL CLOSED LOW WILL TRAVERSE EAST/NORTHEAST THROUGH THE GREAT
LAKES AND SOUTHEAST CANADA THROUGH THE PERIOD. THIS WILL EVENTUALLY
ALLOW AN EXPANSIVE AREA OF SURFACE HIGH PRESSURE TO BUILD INTO THE
REGION BY SATURDAY. ANY SPOTTY SHOWER ACTIVITY APPEARS TO BE
RELEGATED CLOSER TO THE GREAT LAKES ON FRIDAY SO HAVE LEFT THE
FORECAST DRY. TEMPERATURES WILL SHOW A SUBSTANTIAL COOL DOWN FROM
HIGHS IN THE 70S AND 80S ON WEDNESDAY. HIGHS BY THE WEEKEND WILL BE
MAINLY IN THE 60S WITH LOWS DIPPING INTO THE 40S. THESE VALUES WILL
BE SOME 10 TO 15 DEGREES BELOW NORMAL FOR EARLY SEPTEMBER.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
STRATUS DECK NORTHWEST OF THE COLD FROPA THIS AFTERNOON WILL BE
IFR AT FIRST AND THEN LIFT TO MVFR WITH AN INCREASED CHANCE FOR
SOME PASSING SHOWERS.
ACTIVITY WILL MOVE SOUTHEAST THROUGH THE DAY AND WITH DAYTIME
HEATING SOME THUNDERSTORMS MAY BEGIN TO POP...GENERALLY SOUTHEAST
OF I-71 CORRIDOR AND AWAY FROM TAF SITES.
CLOUD COVER WILL LIFT AND DISPERSE LATER TODAY UNDER A DRYING
NORTH WIND. SKIES WILL CLEAR TONIGHT THOUGH ENOUGH LOW LEVEL
MOISTURE MAY BE PRESENT FOR SOME PASSING SC AND DAYBREAK MVFR
VSBYS IN FOG. ANY SC TONIGHT IS NOT EXPECTED TO BE EXPANSIVE OR
UNIFORM ENOUGH TO MAKE A CIG.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
329 PM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL MOVE SOUTHEAST OF THE COMMONWEALTH LATE
TONIGHT...BRINGING LOCALLY STRONG STORMS AND USHERING MUCH DRIER
AIR INTO CENTRAL AND SOUTHEASTERN PORTIONS OF PENNSYLVANIA.
HIGH PRESSURE OVER THE MIDWEST WILL THEN SLIDE ACROSS
PENNSYLVANIA SUNDAY INTO EARLY NEXT WEEK...AS A WEAK LOW PRESSURE
SYSTEM TRACKS SOUTH OF PENNSYLVANIA AND OFF THE MID ATLANTIC
COAST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STORMS POPPING IN THE AREA OF MAX SFC HEATING FROM LEBANON AND
LANCASTER COUNTIES WESTWARD TO THE LAUREL HIGHLANDS AT MID
AFTERNOON. STORMS ARE MARGINAL...WITH PLENTIFUL CAPE TO INITIATE
BUT LESS THAN MARGINAL SHEAR FOR MAINTENANCE...INTENSIFICATION OR
LONGEVITY. HAVE JUST RECEIVED ONE SMALL MARBLE SIZED HAIL REPORT
FROM LEBANON COUNTY...AND KNOW THAT EXISTING STORMS ARE PRODUCING
BRIEF HEAVY DOWNPOURS...BUT STORM MOTION IS PRECLUDING ANY
FLOODING THREATS AS ANTICIPATED.
LATEST HRRR INDICATES THAT THE SOUTHERN ONE QUARTER TO ONE THIRD
OF CENTRAL PA IS THE MAIN SEVERE THREAT THROUGH LATE AFTERNOON...
WITH THE LOWER SUSQ MOST SUSCEPTIBLE TO ISOLATED SEVERE IN THE
FORM OF DAMAGING WIND GUSTS OR LARGE HAIL. COLD FRONT EVIDENT IN
SFC OBS FROM NEAR KDUJ NORTHEASTWARD TO 10S KELM AT THIS HOUR...
AND A NARROW CONVECTIVE RAINBAND HAS DEVELOPED ALONG IT. TO THE
WEST AND NORTH...PLAIN SHOWER ACTIVITY IS OCCURRING OVER THE
NORTHWEST MOUNTAINS...AND DEWPOINTS HAVE DROPPED TO THE MIDDLE 50S
ACROSS WARREN AND MCKEAN COUNTIES.
SUCCESSIVE UPDATES HAVE DECREASED POPS OVERALL AS CONVECTION AND
THUNDERSTORM THREAT IN PARTICULAR DID NOT MATERIALIZE NORTH OF
I80. A PERIOD OF SHOWERS WILL AFFECT THE NORTHWEST THROUGH LATE
AFTERNOON BEFORE DRIER AIR AND CLEARING ARRIVE THIS EVENING.
TO THE SOUTH...WILL CONTINUE TO MONITOR FOR ISOLATED SEVERE...
WITH AGAIN THE MAIN THREAT THE SOUTH CENTRAL MOUNTAINS THROUGH THE
LOWER SUSQ RIVER VALELY. EVENING SHRA/TSRA ACROSS THE CENTRAL AND
SE COUNTIES WILL GIVE WAY TO CLEARING SKIES LATE TONIGHT...AS
COLD FRONT SETTLES SOUTH OF THE STATE AND HIGH PRES/LOW PWAT AIR
WORKS IN FROM THE WEST. THE CLEARING SKIES AND LGT WIND SHOULD
PROMOTE AREAS OF LATE NIGHT FOG IN THE VALLEYS OF WESTERN PA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
SUNDAY WILL FEATURE INCREASINGLY DRIER AIR MASS...AND PLENTY OF
SUNSHINE AFTER EARLY MORNING FOG DISSIPATES. A MUCH MORE
COMFORTABLE DAY WITH MUCH LESS HUMID AIR MASS WILL BRING AN
ENJOYABLE CLOSE TO THE WEEKEND AS HIGH PRES PASSES NORTH OF PA.
MAXES WILL RANGE FROM THE UPPER 60S NORTH TO THE UPPER 70S OVER
THE LOWER SUSQ RIVER VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
FRONT DROPPING SE THIS AFT WILL BRING MUCH LESS HUMID
AIR TO THE AREA. QUESTION IS HOW FAR NORTH MOISTURE WILL
MAKE IT ON MONDAY INTO TUE...AS SYSTEM ACROSS THE SE LIFTS
NE. MID SHIFT HAD SOME CHC IN FOR MONDAY ALREADY. MINOR
ADJUSTMENTS. DID EDGE TEMPS UP SOME.
THE BIG STORY IS THE COMPLEX LOW FOR THE PLAINS FOR MID
WEEK. THE 00Z 09/06 RUN HAS THIS SYSTEM TRACKING MUCH
FURTHER NW THAN THE EARLIER RUN. THUS TREND IS MOST LIKELY
FOR COLD AIR TO COME IN SLOWER...AND FIRST BATCH OF COLD AIR
NOT TO BE VERY DEEP. UPPER LVL TROUGH MAY TRY TO DEEPEN THE
COLD AIR MORE LATER IN THE WEEK. MINOR ADJUSTMENTS MADE. ALSO
AS UPPER LVL SYSTEM SHEARS...HARD TO SEE MUCH ACTION OFF LAKES
IN OUR AREA.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
COLD FRONT WILL SLIDE SE ACROSS THE CENTRAL AND SOUTHEAST PORTIONS
OF CENTRAL PA THROUGH THE EARLY EVENING HOURS. KEPT VCTS TO IN ALL
TAFS EXCEPT KBFD FOR SEVERAL HOURS THIS AFTERNOON...WITH LOCAL
RESTRICTIONS ARE LIKELY IN HEAVIER SHOWERS/TSTMS.
FROPA MAY BRING ANOTHER BAND OF SHOWERS BEFORE ACTIVITY TAPERS
OFF THIS EVENING. CONDITIONS IMPROVE BEHIND THE FRONT...THOUGH
MVFR CIGS COULD LINGER WELL INTO THE EVENING IN THE WESTERN HIGHER
TERRAIN.
CLEARING SKIES AND TRAPPED MOISTURE COULD BRING REDUCTIONS TO
CIGS/VSBYS LATER TONIGHT INTO SUNDAY MORNING.
OUTLOOK...
SUN...AM FOG POSS.
MON...PATCHY AM VALLEY FOG POSS.
TUE...CHC SHOWERS/TSTMS.
WED...SCT SHOWERS/TSTMS.
THU...SCT SHOWERS/TSTMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DEVOIR
SHORT TERM...DEVOIR
LONG TERM...MARTIN
AVIATION...DEVOIR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
239 PM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL MOVE SOUTHEAST OF THE COMMONWEALTH LATE
TONIGHT...BRINGING LOCALLY STRONG STORMS AND USHERING MUCH DRIER
AIR INTO CENTRAL AND SOUTHEASTERN PORTIONS OF PENNSYLVANIA.
HIGH PRESSURE OVER THE MIDWEST WILL THEN SLIDE ACROSS
PENNSYLVANIA SUNDAY INTO EARLY NEXT WEEK...AS A WEAK LOW PRESSURE
SYSTEM TRACKS SOUTH OF PENNSYLVANIA AND OFF THE MID ATLANTIC
COAST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STORMS POPPING IN THE AREA OF MAX SFC HEATING FROM LEBANON AND
LANCASTER COUNTIES WESTWARD TO THE LAUREL HIGHLANDS AT MID
AFTERNOON. STORMS ARE MARGINAL...WITH PLENTIFUL CAPE TO INITIATE
BUT LESS THAN MARGINAL SHEAR FOR MAINTENANCE...INTENSIFICATION OR
LONGEVITY. HAVE JUST RECEIVED ONE SMALL MARBLE SIZED HAIL REPORT
FROM LEBANON COUNTY...AND KNOW THAT EXISTING STORMS ARE PRODUCING
BRIEF HEAVY DOWNPOURS...BUT STORM MOTION IS PRECLUDING ANY
FLOODING THREATS AS ANTICIPATED.
LATEST HRRR INDICATES THAT THE SOUTHERN ONE QUARTER TO ONE THIRD
OF CENTRAL PA IS THE MAIN SEVERE THREAT THROUGH LATE AFTERNOON...
WITH THE LOWER SUSQ MOST SUSCEPTIBLE TO ISOLATED SEVERE IN THE
FORM OF DAMAGING WIND GUSTS OR LARGE HAIL. COLD FRONT EVIDENT IN
SFC OBS FROM NEAR KDUJ NORTHEASTWARD TO 10S KELM AT THIS HOUR...
AND A NARROW CONVECTIVE RAINBAND HAS DEVELOPED ALONG IT. TO THE
WEST AND NORTH...PLAIN SHOWER ACTIVITY IS OCCURRING OVER THE
NORTHWEST MOUNTAINS...AND DEWPOINTS HAVE DROPPED TO THE MIDDLE 50S
ACROSS WARREN AND MCKEAN COUNTIES.
SUCCESSIVE UPDATES HAVE DECREASED POPS OVERALL AS CONVECTION AND
THUNDERSTORM THREAT IN PARTICULAR DID NOT MATERIALIZE NORTH OF
I80. A PERIOD OF SHOWERS WILL AFFECT THE NORTHWEST THROUGH LATE
AFTERNOON BEFORE DRIER AIR AND CLEARING ARRIVE THIS EVENING.
TO THE SOUTH...WILL CONTINUE TO MONITOR FOR ISOLATED SEVERE...
WITH AGAIN THE MAIN THREAT THE SOUTH CENTRAL MOUNTAINS THROUGH THE
LOWER SUSQ RIVER VALELY. EVENING SHRA/TSRA ACROSS THE CENTRAL AND
SE COUNTIES WILL GIVE WAY TO CLEARING SKIES LATE TONIGHT...AS
COLD FRONT SETTLES SOUTH OF THE STATE AND HIGH PRES/LOW PWAT AIR
WORKS IN FROM THE WEST. THE CLEARING SKIES AND LGT WIND SHOULD
PROMOTE AREAS OF LATE NIGHT FOG IN THE VALLEYS OF WESTERN PA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
SUNDAY WILL FEATURE INCREASINGLY DRIER AIR MASS...AND PLENTY OF
SUNSHINE AFTER EARLY MORNING FOG DISSIPATES. A MUCH MORE
COMFORTABLE DAY WITH MUCH LESS HUMID AIR MASS WILL BRING AN
ENJOYABLE CLOSE TO THE WEEKEND AS HIGH PRES PASSES NORTH OF PA.
MAXES WILL RANGE FROM THE UPPER 60S NORTH TO THE UPPER 70S OVER
THE LOWER SUSQ RIVER VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
BULK OF MED RANGE GUIDANCE INDICATES A CLOUDIER AND PERHAPS
SHOWERY MON/TUE THAN WAS EARLIER THOUGHT...AS SHORTWAVE AND ASSOC
WEAK WAVE OF LOW PRES SLIDES JUST SOUTH OF PA. TIMING OF THIS
FEATURE IN GEFS OUTPUT SUGGESTS THE BEST CHANCE FOR A FEW -SHRA
WILL COME LATE MONDAY INTO EARLY TUESDAY ACROSS SOUTHERN PA.
FAIRLY GOOD AGREEMENT LATE WEEK AMONGST MED RANGE MDLS...ALL OF
WHICH TRACK A DEEPENING SFC LOW WEST OF PA THRU THE GRT LKS.
TRAILING COLD FRONT AND ASSOC SHOWER THREAT IS LIKELY TO COME
THRU CENTRAL PA THURSDAY.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
COLD FRONT WILL SLIDE SE ACROSS THE CENTRAL AND SOUTHEAST PORTIONS
OF CENTRAL PA THROUGH THE EARLY EVENING HOURS. KEPT VCTS TO IN ALL
TAFS EXCEPT KBFD FOR SEVERAL HOURS THIS AFTERNOON...WITH LOCAL
RESTRICTIONS ARE LIKELY IN HEAVIER SHOWERS/TSTMS.
FROPA MAY BRING ANOTHER BAND OF SHOWERS BEFORE ACTIVITY TAPERS
OFF THIS EVENING. CONDITIONS IMPROVE BEHIND THE FRONT...THOUGH
MVFR CIGS COULD LINGER WELL INTO THE EVENING IN THE WESTERN HIGHER
TERRAIN.
CLEARING SKIES AND TRAPPED MOISTURE COULD BRING REDUCTIONS TO
CIGS/VSBYS LATER TONIGHT INTO SUNDAY MORNING.
OUTLOOK...
SUN...AM FOG POSS.
MON...PATCHY AM VALLEY FOG POSS.
TUE...CHC SHOWERS/TSTMS.
WED...SCT SHOWERS/TSTMS.
THU...SCT SHOWERS/TSTMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DEVOIR
SHORT TERM...DEVOIR
LONG TERM...FITZGERALD/GARTNER
AVIATION...DEVOIR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1049 AM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE STATE THIS AFTERNOON
AND TONIGHT. HIGH PRESSURE OVER THE MIDWEST WILL THEN SLIDE
ACROSS PENNSYLVANIA SUNDAY INTO EARLY NEXT WEEK...AS A WEAK LOW
PRESSURE SYSTEM TRACKS SOUTH OF PENNSYLVANIA AND OFF THE MID
ATLANTIC COAST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLEAR SKIES EXTEND FROM FRANKLIN TO LANCASTER COUNTIES AT MID TO
LATE MORNING...ENABLING SFC TEMPS TO WARM TO THE LOWER 80S AS OF
10 AM. EARLIER FOG HAS DISSIPATED. MID TO HIGH CLOUD CONVECTIVE
DEBRIS FROM OVERNIGHT SQUALL LINE DISSIPATING EXTENDS FROM WV
THROUGH THE LAUREL HIGHLANDS NORTHEASTWARD TO THE POCONO PLATEAU.
SCT-BKN LAYERED CLOUDS EXTEND FROM THE WEST CENTRAL MOUNTAINS
NORTHWARD ACROSS THE REMAINDER OF NORTH CENTRAL PA AHEAD OF THE
SLOWLY APPROACHING FRONTAL ZONE...WHICH APPEARS WILL CROSS PA IN
TWO DISTINCT PIECES TODAY...ACCORDING TO 4KM SPC WRF IDEA AND
EXTRAPOLATING CURRENT RADAR VIEW.
LATEST REGIONAL RADAR MOSAIC INDICATES AN INITIAL NARROW BAND OF
SHOWERS FROM NORTHEAST OHIO THROUGH NORTHWEST PA AND INTO THE
FINGERLAKES REGION OF WESTERN NY...SLOWLY PUSHING SOUTHEASTWARD.
NEW HRRR AND 00Z 4KM SPC WRF TAKES THIS INITIAL BATCH OF SHOWERS
ACROSS THE NORTHWEST THIRD TO HALF OF CENTRAL PA THROUGH
16-17Z...THEN DISSIPATES IT IN FAVOR OF THE FRONTAL ZONE
CONVECTION WHICH AGAIN TRACKS ACROSS THE NORTHWEST MOUNTAINS FROM
THE EARLY TO MID AFTERNOON HOURS AND REACHES THE CENTRAL MOUNTAINS
MID TO LATE AFTERNOON. EARLIER HRRR HAS TRENDED TOWARDS 4KM SPC
WRF DEPICTION...AND IS NOT LONGER DEPICTING CONVECTION POSSIBLE
AT ANY TIME FROM MID TO LATE MORNING ONWARD ACROSS ALL BUT FAR
SOUTHEAST PA AS THE EARLIER MORNING RUN HAD. ISOLATED ACTIVITY IS
LIKELY TO SPROUT OVER THE LOWER SUSQ IN THE AREA OF MAX SFC
HEATING THIS MORNING (TEMPS WHILE WRITING THIS ARE LIKELY TO WARM
INTO THE MID 80S AT THE TOP OF NEXT HOUR)...BUT THINK THE MAIN
ACTIVITY WILL COME WITH THE ACTUAL FRONT LATER THIS AFTERNOON AND
EVENING.
MODIFIED TIMING OF HIGHER CONVECTIVE POPS LATER THIS MORNING AND
AFTERNOON BASED ON CURRENT RADAR ACTIVITY AND LATEST HRRR...WHICH
AS MENTIONED TOWARDS THE OVERNIGHT 4KM SPC WRF TIMING. THIS DELAYS
THE HIGHEST CONVECTIVE POPS ACROSS CENTRAL PA TO ~20Z OR
AFTERWARDS. MORNING SHOWERS ACROSS THE NORTHWEST MOUNTAINS WILL
PUSH SOUTHEAST AND TRANSITION INTO NUMEROUS +SHRA AND A FEW BKN
LINES OF TSRA IN THE AFTERNOON OVR THE SERN HALF OF THE AREA.
FARTHER NORTH...THE MAIN FRONTAL BAND OF CONVECTION SHOULD
INTENSITY EARLY TO MID AFTERNOON OVER THE NORTHWEST MOUNTAINS AND
SLIDE SOUTHEASTWARD INTO THE CENTRAL MOUNTAINS MID TO LATE
AFTERNOON. AS EARLIER MENTIONED...SREF PROB FOR CAPES EXCEEDING
2000 J/KG RAMP UP QUICKLY IN THE 15-18Z TIMEFRAME ALONG AND EAST
OF A LINE FROM NEAR KJST...TO KUNV AND KELM.
ISOLATED SEVERE IS POSSIBLE...LATEST SPC OUTLOOK KEEPS
SCHUYLKILL...NORTHUMBERLAND... MONTOUR COLUMBIA AND SULLIVAN
COUNTIES IN DAY 1 SLIGHT RISK AREA. SHEAR APPEARS TO BE LACKING
FOR WIDESPREAD SEVERE WEATHER...BUT SOME STORMS WILL AT LEAST BE
MARGINAL WITH AN ISOLATED THREAT OF SEVERE WIND GUSTS...ESPECIALLY
ACROSS THE SOUTHERN QUARTER TO THIRD OF CENTRAL PA. BEST CHC STILL
APPEARS TO BE ACROSS THE LOWER SUSQ VALLEY DURING THE MID
AFTERNOON TO EARLY EVENING.
MAX TEMPS THIS AFTERNOON WILL VARY FROM ONLY NEAR 70F ACROSS THE
NORTHWEST MOUNTAINS...TO THE UPPER 80S IN THE SE ZONES. DEWPOINTS
WILL MAKE FOR ONE LAST VERY UNCOMFORTABLE DAY BEFORE DRIER AIR
ARRIVES LATER TONIGHT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
EVENING SHRA/TSRA ACROSS THE SE COUNTIES WILL GIVE WAY TO CLEARING
SKIES LATE TONIGHT...AS COLD FRONT SETTLES SOUTH OF THE STATE AND
HIGH PRES/LOW PWAT AIR WORKS IN FROM THE WEST. THE CLEARING SKIES
AND LGT WIND SHOULD PROMOTE AREAS OF LATE NIGHT FOG IN THE VALLEYS
OF WESTERN PA.
ANY EARLY FOG SHOULD GIVE WAY TO MSUNNY AND MUCH LESS HUMID WX
SUNDAY...AS HIGH PRES PASSES NORTH OF PA. GEFS MEAN 925 TEMPS
SUPPORT MAX TEMPS FROM THE U60S OVR THE HIGH TERRAIN OF THE
ALLEGHENIES...TO THE U70S ACROSS THE LOWER SUSQ VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BULK OF MED RANGE GUIDANCE INDICATES A CLOUDIER AND PERHAPS
SHOWERY MON/TUE THAN WAS EARLIER THOUGHT...AS SHORTWAVE AND ASSOC
WEAK WAVE OF LOW PRES SLIDES JUST SOUTH OF PA. TIMING OF THIS
FEATURE IN GEFS OUTPUT SUGGESTS THE BEST CHANCE FOR A FEW -SHRA
WILL COME LATE MONDAY INTO EARLY TUESDAY ACROSS SOUTHERN PA.
FAIRLY GOOD AGREEMENT LATE WEEK AMONGST MED RANGE MDLS...ALL OF
WHICH TRACK A DEEPENING SFC LOW WEST OF PA THRU THE GRT LKS.
TRAILING COLD FRONT AND ASSOC SHOWER THREAT IS LIKELY TO COME
THRU CENTRAL PA THURSDAY.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS PREVAILING THROUGH LATE MORNING WITH MID TO HIGH
CLOUD CIGS STREAMING IN AHEAD OF AN APPROACHING COLD FRONT.
COLD FRONT IS PROGGED TO ENTER THE NW MTNS LATE THIS
MORNING...THEN SLIDE SE ACROSS THE REST OF CENTRAL PA DURING THE
AFTN AND EARLY EVENING HOURS. TIMING OF FRONT CONTINUES TO SUGGEST
BAND OF SHRA WILL MOVE INTO THE NW MTNS BTWN 12Z-15Z. MORNING
SHOWERS ACROSS THE NW MTNS SHOULD PUSH SE AND TRANSITION/GROW INTO
NUMEROUS +SHRA AND A FEW BKN LINES OF TSRA IN THE AFTERNOON OVR
THE SERN HALF OF THE FCST AREA...WHERE EARLY HEATING WILL RESULT
IN A MODERATELY UNSTABLE PRE-FRONTAL AIR MASS BY AFTN. ADDED VCTS
TO ALL TAFS EXCEPT KBFD FOR SEVERAL HOURS THIS AFTERNOON...AND
LOCAL RESTRICTIONS ARE LIKELY IN HEAVIER SHOWERS/TSTMS.
FROPA MAY BRING ANOTHER BAND OF SHOWERS BEFORE ACTIVITY TAPERS
OFF THIS AFTERNOON AND EVENING. CONDITIONS IMPROVE BEHIND THE
FRONT...THOUGH MVFR CIGS COULD LINGER WELL INTO THE EVENING IN
THE WESTERN HIGHER TERRAIN.
CLEARING SKIES AND TRAPPED MOISTURE COULD BRING REDUCTIONS TO
CIGS/VSBYS LATER TONIGHT INTO SUNDAY MORNING.
OUTLOOK...
SUN...AM FOG POSS.
MON...PATCHY AM VALLEY FOG POSS.
TUE...CHC SHOWERS/TSTMS.
WED...SCT SHOWERS/TSTMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR/FITZGERALD
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/GARTNER
AVIATION...DEVOIR/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1048 AM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE STATE THIS AFTERNOON
AND TONIGHT. HIGH PRESSURE OVER THE MIDWEST WILL THEN SLIDE
ACROSS PENNSYLVANIA SUNDAY INTO EARLY NEXT WEEK...AS A WEAK LOW
PRESSURE SYSTEM TRACKS SOUTH OF PENNSYLVANIA AND OFF THE MID
ATLANTIC COAST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLEAR SKIES EXTEND FROM FRANKLIN TO LANCASTER COUNTIES AT MID TO
LATE MORNING...ENABLING SFC TEMPS TO WARM TO THE LOWER 80S AS OF
10 AM. EARLIER FOG HAS DISSIPATED. MID TO HIGH CLOUD CONVECTIVE
DEBRIS FROM OVERNIGHT SQUALL LINE DISSIPATING EXTENDS FROM WV
THROUGH THE LAUREL HIGHLANDS NORTHEASTWARD TO THE POCONO PLATEAU.
SCT-BKN LAYERED CLOUDS EXTEND FROM THE WEST CENTRAL MOUNTAINS
NORTHWARD ACROSS THE REMAINDER OF NORTH CENTRAL PA AHEAD OF THE
SLOWLY APPROACHING FRONTAL ZONE...WHICH APPEARS WILL CROSS PA IN
TWO DISTINCT PIECES TODAY...ACCORDING TO 4KM SPC WRF IDEA AND
EXTRAPOLATING CURRENT RADAR VIEW.
LATEST REGIONAL RADAR MOSAIC INDICATES AN INITIAL NARROW BAND OF
SHOWERS FROM NORTHEAST OHIO THROUGH NORTHWEST PA AND INTO THE
FINGERLAKES REGION OF WESTERN NY...SLOWLY PUSHING SOUTHEASTWARD.
NEW HRRR AND 00Z 4KM SPC WRF TAKES THIS INITIAL BATCH OF SHOWERS
ACROSS THE NORTHWEST THIRD TO HALF OF CENTRAL PA THROUGH
16-17Z...THEN DISSIPATES IT IN FAVOR OF THE FRONTAL ZONE
CONVECTION WHICH AGAIN TRACKS ACROSS THE NORTHWEST MOUNTAINS FROM
THE EARLY TO MID AFTERNOON HOURS AND REACHES THE CENTRAL MOUNTAINS
MID TO LATE AFTERNOON. EARLIER HRRR HAS TRENDED TOWARDS 4KM SPC
WRF DEPICTION...AND IS NOT LONGER DEPICTING CONVECTION POSSIBLE
AT ANY TIME FROM MID TO LATE MORNING ONWARD ACROSS ALL BUT FAR
SOUTHEAST PA AS THE EARLIER MORNING RUN HAD. ISOLATED ACTIVITY IS
LIKELY TO SPROUT OVER THE LOWER SUSQ IN THE AREA OF MAX SFC
HEATING THIS MORNING (TEMPS WHILE WRITING THIS ARE LIKELY TO WARM
INTO THE MID 80S AT THE TOP OF NEXT HOUR)...BUT THINK THE MAIN
ACTIVITY WILL COME WITH THE ACTUAL FRONT LATER THIS AFTERNOON AND
EVENING.
MODIFIED TIMING OF HIGHER CONVECTIVE POPS LATER THIS MORNING AND
AFTERNOON BASED ON CURRENT RADAR ACTIVITY AND LATEST HRRR...WHICH
AS MENTIONED TOWARDS THE OVERNIGHT 4KM SPC WRF TIMING. THIS DELAYS
THE HIGHEST CONVECTIVE POPS ACROSS CENTRAL PA TO ~20Z OR
AFTERWARDS. MORNING SHOWERS ACROSS THE NORTHWEST MOUNTAINS WILL
PUSH SOUTHEAST AND TRANSITION INTO NUMEROUS +SHRA AND A FEW BKN
LINES OF TSRA IN THE AFTERNOON OVR THE SERN HALF OF THE AREA.
FARTHER NORTH...THE MAIN FRONTAL BAND OF CONVECTION SHOULD
INTENSITY EARLY TO MID AFTERNOON OVER THE NORTHWEST MOUNTAINS AND
SLIDE SOUTHEASTWARD INTO THE CENTRAL MOUNTAINS MID TO LATE
AFTERNOON. AS EARLIER MENTIONED...SREF PROB FOR CAPES EXCEEDING
2000 J/KG RAMP UP QUICKLY IN THE 15-18Z TIMEFRAME ALONG AND EAST
OF A LINE FROM NEAR KJST...TO KUNV AND KELM.
ISOLATED SEVERE IS POSSIBLE...LATEST SPC OUTLOOK KEEPS
SCHUYLKILL...NORTHUMBERLAND... MONTOUR COLUMBIA AND SULLIVAN
COUNTIES IN DAY 1 SLIGHT RISK AREA. SHEAR APPEARS TO BE LACKING
FOR WIDESPREAD SEVERE WEATHER...BUT SOME STORMS WILL AT LEAST BE
MARGINAL WITH AN ISOLATED THREAT OF SEVERE WIND GUSTS...ESPECIALLY
ACROSS THE SOUTHERN QUARTER TO THIRD OF CENTRAL PA. BEST CHC STILL
APPEARS TO BE ACROSS THE LOWER SUSQ VALLEY DURING THE MID
AFTERNOON TO EARLY EVENING.
MAX TEMPS THIS AFTERNOON WILL VARY FROM ONLY NEAR 70F ACROSS THE
NORTHWEST MOUNTAINS...TO THE UPPER 80S IN THE SE ZONES. DEWPOINTS
WILL MAKE FOR ONE LAST VERY UNCOMFORTABLE DAY BEFORE DRIER AIR
ARRIVES LATER TONIGHT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
EVENING SHRA/TSRA ACROSS THE SE COUNTIES WILL GIVE WAY TO CLEARING
SKIES LATE TONIGHT...AS COLD FRONT SETTLES SOUTH OF THE STATE AND
HIGH PRES/LOW PWAT AIR WORKS IN FROM THE WEST. THE CLEARING SKIES
AND LGT WIND SHOULD PROMOTE AREAS OF LATE NIGHT FOG IN THE VALLEYS
OF WESTERN PA.
ANY EARLY FOG SHOULD GIVE WAY TO MSUNNY AND MUCH LESS HUMID WX
SUNDAY...AS HIGH PRES PASSES NORTH OF PA. GEFS MEAN 925 TEMPS
SUPPORT MAX TEMPS FROM THE U60S OVR THE HIGH TERRAIN OF THE
ALLEGHENIES...TO THE U70S ACROSS THE LOWER SUSQ VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BULK OF MED RANGE GUIDANCE INDICATES A CLOUDIER AND PERHAPS
SHOWERY MON/TUE THAN WAS EARLIER THOUGHT...AS SHORTWAVE AND ASSOC
WEAK WAVE OF LOW PRES SLIDES JUST SOUTH OF PA. TIMING OF THIS
FEATURE IN GEFS OUTPUT SUGGESTS THE BEST CHANCE FOR A FEW -SHRA
WILL COME LATE MONDAY INTO EARLY TUESDAY ACROSS SOUTHERN PA.
FAIRLY GOOD AGREEMENT LATE WEEK AMONGST MED RANGE MDLS...ALL OF
WHICH TRACK A DEEPENING SFC LOW WEST OF PA THRU THE GRT LKS.
TRAILING COLD FRONT AND ASSOC SHOWER THREAT IS LIKELY TO COME
THRU CENTRAL PA THURSDAY.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
REDUCTIONS IN FOG/LOW CLOUDS PERSIST ACROSS THE EAST FROM KIPT-
KMDT-KLNS AT 12Z. THESE WILL GRADUALLY IMPROVE TO MVFR BY 13-14Z
AND EVENTUALLY TO VFR BY LATE MORNING. VFR CONDITIONS ACROSS THE
WEST WITH HIGH CLOUDS STREAMING IN AHEAD OF AN APPROACHING COLD
FRONT.
COLD FRONT IS PROGGED TO ENTER THE NW MTNS LATE THIS
MORNING...THEN SLIDE SE ACROSS THE REST OF CENTRAL PA DURING THE
AFTN AND EARLY EVENING HOURS. TIMING OF FRONT CONTINUES TO SUGGEST
BAND OF SHRA WILL MOVE INTO THE NW MTNS BTWN 12Z-15Z. MORNING
SHOWERS ACROSS THE NW MTNS SHOULD PUSH SE AND TRANSITION/GROW INTO
NUMEROUS +SHRA AND A FEW BKN LINES OF TSRA IN THE AFTERNOON OVR
THE SERN HALF OF THE FCST AREA...WHERE EARLY HEATING WILL RESULT
IN A MODERATELY UNSTABLE PRE-FRONTAL AIR MASS BY AFTN. ADDED VCTS
TO ALL TAFS EXCEPT KBFD FOR SEVERAL HOURS THIS AFTERNOON...AND
LOCAL RESTRICTIONS ARE LIKELY IN HEAVIER SHOWERS/TSTMS.
FROPA MAY BRING ANOTHER BAND OF SHOWERS BEFORE ACTIVITY TAPERS
OFF THIS AFTERNOON AND EVENING. CONDITIONS IMPROVE BEHIND THE
FRONT...THOUGH MVFR CIGS COULD LINGER WELL INTO THE EVENING IN
THE WESTERN HIGHER TERRAIN.
CLEARING SKIES AND TRAPPED MOISTURE COULD BRING REDUCTIONS TO
CIGS/VSBYS LATER TONIGHT INTO SUNDAY MORNING.
OUTLOOK...
SUN...AM FOG POSS.
MON...PATCHY AM VALLEY FOG POSS.
TUE...CHC SHOWERS/TSTMS.
WED...SCT SHOWERS/TSTMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR/FITZGERALD
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/GARTNER
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
849 AM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE STATE LATE TODAY.
HIGH PRESSURE OVER THE MIDWEST WILL THEN SLIDE ACROSS PENNSYLVANIA
SUNDAY INTO EARLY NEXT WEEK...AS A WEAK LOW PRESSURE SYSTEM TRACKS
SOUTH OF PENNSYLVANIA AND OFF THE MID ATLANTIC COAST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLEAR SKIES FROM FRANKLIN TO LANCASTER COUNTIES ENABLED PATCHY
DENSE FOG TO DEVELOP EARLY THIS MORNING...WHICH SHOULD SLOWLY MIX
OUT BY 930 AM. MID TO HIGH CLOUD CONVECTIVE DEBRIS FROM LATE
EVENING SQUALL LINE OVER THE EASTERN LAKES AND FAR NORTHWEST PA
EXTENDS FROM SRN OHIO THROUGH THE POCONO PLATEAU REGION. LAYERED
SCT TO BROKEN CLOUDS EXTEND FROM THE WEST CENTRAL MOUNTAINS
NORTHWARD ACROSS THE REMAINDER OF NORTH CENTRAL PA AHEAD OF THE
SLOWLY APPROACHING FRONTAL ZONE...WHICH APPEARS WILL CROSS PA IN
TWO DISTINCT PIECES TODAY...ACCORDING TO 4KM SPC WRF IDEA AND
EXTRAPOLATING CURRENT RADAR VIEW.
LATEST REGIONAL RADAR MOSAIC INDICATES AN INITIAL NARROW BAND OF
SHOWERS FROM NORTHEAST OHTO THE NW PA AND WESTERN NY LAKE ERIE
SHORE WHICH WILL DROP INTO THE NORTHWEST MOUNTAINS THIS MORNING.
THE AFOREMENTIONED 4KM SPC WRF BRINGS AN INITIAL BATCH OF SHOWERS
ACROSS THE NORTHWEST THIRD TO HALF OF CENTRAL PA THROUGH
16Z...THEN DISSIPATES IT IN FAVOR OF THE FRONTAL ZONE CONVECTION
WHICH AGAIN TRACKS ACROSS THE NORTHWEST MOUNTAINS FROM THE EARLY
TO MID AFTERNOON HOURS AND REACHES THE CENTRAL MOUNTAINS MID TO
LATE AFTERNOON. HRRR SEEMS TO BE EXHIBITING ITS TYPICAL BIAS OF
OVER-INITIATING CONVECTION IN WEAK FORCING ENVIRONMENTS AND
SUGGESTS CONVECTION IS POSSIBLE AT ANY TIME FROM MID TO LATE
MORNING ONWARD ACROSS ALL BUT FAR SOUTHEAST PA. WHILE IT`S A
POSSIBILITY GIVEN AVAILABLE CAPE...AM CONSIDERING THIS AN OUTLIER
FOR NOW WITHOUT DISCOUNTING IT.
MODIFIED TIMING OF HIGHER CONVECTIVE POPS LATER THIS MORNING AND
AFTERNOON TOWARDS THE 4KM SPC WRF TIMING...WHICH PRODUCED A SLIGHT
DELAY IN ONSET OF GREATEST AREAL COVERAGE BY 1-2 HOURS. EARLIER
THINKING OF MORNING SHOWERS ACROSS THE NW MTNS PUSHING SE AND
TRANSITIONING INTO NUMEROUS +SHRA AND A FEW BKN LINES OF TSRA IN
THE AFTERNOON OVR THE SERN HALF OR SO OF THE FCST AREA IS STILL IN
PLAY. GREATEST SFC HEATING WILL TAKE PLACE OVER THE LOWER SUSQ
THIS MORNING RESULTING IN MODERATELY UNSTABLE PRE-FRONTAL
ENVIRONMENT THIS AFTERNOON. AS EARLIER MENTIONED...SREF PROB FOR
CAPES EXCEEDING 2000 J/KG RAMP UP QUICKLY IN THE 15-18Z TIMEFRAME
ALONG AND EAST OF A LINE FROM NEAR KJST...TO KUNV AND KELM.
SHEAR APPEARS TO BE LACKING FOR WIDESPREAD SEVERE WEATHER...BUT
SOME STORMS WILL AT LEAST BE MARGINAL WITH AN ISOLATED THREAT OF
SEVERE WIND GUSTS...ESPECIALLY ACROSS THE SOUTHERN QUARTER TO
THIRD OF CENTRAL PA. BEST CHC STILL APPEARS TO BE ACROSS THE
LOWER SUSQ VALLEY DURING THE MID AFTERNOON TO EARLY EVENING.
MAX TEMPS THIS AFTERNOON WILL VARY FROM ONLY NEAR 70F ACROSS THE
NORTHWEST MOUNTAINS...TO THE UPPER 80S IN THE SE ZONES. DEWPOINTS
WILL MAKE FOR ONE LAST VERY UNCOMFORTABLE DAY BEFORE DRIER AIR
ARRIVES LATER TONIGHT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
EVENING SHRA/TSRA ACROSS THE SE COUNTIES WILL GIVE WAY TO CLEARING
SKIES LATE TONIGHT...AS COLD FRONT SETTLES SOUTH OF THE STATE AND
HIGH PRES/LOW PWAT AIR WORKS IN FROM THE WEST. THE CLEARING SKIES
AND LGT WIND SHOULD PROMOTE AREAS OF LATE NIGHT FOG IN THE VALLEYS
OF WESTERN PA.
ANY EARLY FOG SHOULD GIVE WAY TO MSUNNY AND MUCH LESS HUMID WX
SUNDAY...AS HIGH PRES PASSES NORTH OF PA. GEFS MEAN 925 TEMPS
SUPPORT MAX TEMPS FROM THE U60S OVR THE HIGH TERRAIN OF THE
ALLEGHENIES...TO THE U70S ACROSS THE LOWER SUSQ VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BULK OF MED RANGE GUIDANCE INDICATES A CLOUDIER AND PERHAPS
SHOWERY MON/TUE THAN WAS EARLIER THOUGHT...AS SHORTWAVE AND ASSOC
WEAK WAVE OF LOW PRES SLIDES JUST SOUTH OF PA. TIMING OF THIS
FEATURE IN GEFS OUTPUT SUGGESTS THE BEST CHANCE FOR A FEW -SHRA
WILL COME LATE MONDAY INTO EARLY TUESDAY ACROSS SOUTHERN PA.
FAIRLY GOOD AGREEMENT LATE WEEK AMONGST MED RANGE MDLS...ALL OF
WHICH TRACK A DEEPENING SFC LOW WEST OF PA THRU THE GRT LKS.
TRAILING COLD FRONT AND ASSOC SHOWER THREAT IS LIKELY TO COME
THRU CENTRAL PA THURSDAY.
&&
.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
REDUCTIONS IN FOG/LOW CLOUDS PERSIST ACROSS THE EAST FROM KIPT-
KMDT-KLNS AT 12Z. THESE WILL GRADUALLY IMPROVE TO MVFR BY 13-14Z
AND EVENTUALLY TO VFR BY LATE MORNING. VFR CONDITIONS ACROSS THE
WEST WITH HIGH CLOUDS STREAMING IN AHEAD OF AN APPROACHING COLD
FRONT.
COLD FRONT IS PROGGED TO ENTER THE NW MTNS LATE THIS
MORNING...THEN SLIDE SE ACROSS THE REST OF CENTRAL PA DURING THE
AFTN AND EARLY EVENING HOURS. TIMING OF FRONT CONTINUES TO SUGGEST
BAND OF SHRA WILL MOVE INTO THE NW MTNS BTWN 12Z-15Z. MORNING
SHOWERS ACROSS THE NW MTNS SHOULD PUSH SE AND TRANSITION/GROW INTO
NUMEROUS +SHRA AND A FEW BKN LINES OF TSRA IN THE AFTERNOON OVR
THE SERN HALF OF THE FCST AREA...WHERE EARLY HEATING WILL RESULT
IN A MODERATELY UNSTABLE PRE-FRONTAL AIR MASS BY AFTN. ADDED VCTS
TO ALL TAFS EXCEPT KBFD FOR SEVERAL HOURS THIS AFTERNOON...AND
LOCAL RESTRICTIONS ARE LIKELY IN HEAVIER SHOWERS/TSTMS.
FROPA MAY BRING ANOTHER BAND OF SHOWERS BEFORE ACTIVITY TAPERS
OFF THIS AFTERNOON AND EVENING. CONDITIONS IMPROVE BEHIND THE
FRONT...THOUGH MVFR CIGS COULD LINGER WELL INTO THE EVENING IN
THE WESTERN HIGHER TERRAIN.
CLEARING SKIES AND TRAPPED MOISTURE COULD BRING REDUCTIONS TO
CIGS/VSBYS LATER TONIGHT INTO SUNDAY MORNING.
OUTLOOK...
SUN...AM FOG POSS.
MON...PATCHY AM VALLEY FOG POSS.
TUE...CHC SHOWERS/TSTMS.
WED...SCT SHOWERS/TSTMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/GARTNER
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
838 AM EDT SAT SEP 6 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE STATE LATE TODAY.
HIGH PRESSURE OVER THE MIDWEST WILL THEN SLIDE ACROSS PENNSYLVANIA
SUNDAY INTO EARLY NEXT WEEK...AS A WEAK LOW PRESSURE SYSTEM TRACKS
SOUTH OF PENNSYLVANIA AND OFF THE MID ATLANTIC COAST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLEAR SKIES FROM FRANKLIN TO LANCASTER COUNTIES ENABLED PATCHY
DENSE FOG TO DEVELOP EARLY THIS MORNING...WHICH SHOULD SLOWLY MIX
OUT BY 930 AM. MID TO HIGH CLOUD CONVECTIVE DEBRIS FROM LATE
EVENING SQUALL LINE OVER THE EASTERN LAKES AND FAR NORTHWEST PA
EXTENDS FROM SRN OHIO THROUGH THE POCONO PLATEAU REGION. LAYERED
SCT TO BROKEN CLOUDS EXTEND FROM THE WEST CENTRAL MOUNTAINS
NORTHWARD ACROSS THE REMAINDER OF NORTH CENTRAL PA AHEAD OF THE
SLOWLY APPROACHING FRONTAL ZONE...WHICH APPEARS WILL CROSS PA IN
TWO DISTINCT PIECES TODAY...ACCORDING TO 4KM SPC WRF IDEA AND
EXTRAPOLATING CURRENT RADAR VIEW. LATEST REGIONAL RADAR MOSAIC
INDICATES AN INITIAL NARROW BAND OF SHOWERS FROM NORTHEAST OHTO
THE NW PA AND WESTERN NY LAKE ERIE SHORE WHICH WILL DROP INTO THE
NORTHWEST MOUNTAINS THIS MORNING. THE AFOREMENTIONED 4KM SPC WRF
BRINGS AN INITIAL BATCH OF SHOWERS ACROSS THE NORTHWEST THIRD TO
HALF OF CENTRAL PA THROUGH 16Z...THEN DISSIPATES IT IN FAVOR OF
THE FRONTAL ZONE CONVECTION WHICH AGAIN TRACKS ACROSS THE
NORTHWEST MOUNTAINS FROM THE EARLY TO MID AFTERNOON HOURS AND
REACHES THE CENTRAL MOUNTAINS MID TO LATE AFTERNOON. HRRR SEEMS TO
BE EXHIBITING ITS TYPICAL BIAS OF OVER-INITIATING CONVECTION IN
WEAK FORCING ENVIRONMENTS AND SUGGESTS CONVECTION IS POSSIBLE AT
ANY TIME FROM MID TO LATE MORNING ONWARD ACROSS ALL BUT FAR
SOUTHEAST PA. WHILE IT`S A POSSIBILITY GIVEN AVAILABLE CAPE...AM
CONSIDERING THIS AN OUTLIER FOR NOW WITHOUT DISCOUNTING IT.
MODIFIED TIMING OF HIGHER CONVECTIVE POPS LATER THIS MORNING AND
AFTERNOON TOWARDS THE 4KM SPC WRF TIMING...WHICH PRODUCED A SLIGHT
DELAY IN ONSET OF GREATEST AREAL COVERAGE BY 1-2 HOURS. EARLIER
THINKING OF MORNING SHOWERS ACROSS THE NW MTNS PUSHING SE AND
TRANSITIONING INTO NUMEROUS +SHRA AND A FEW BKN LINES OF TSRA IN
THE AFTERNOON OVR THE SERN HALF OR SO OF THE FCST AREA IS STILL IN
PLAY. GREATEST SFC HEATING WILL TAKE PLACE OVER THE LOWER SUSQ
THIS MORNING RESULTING IN MODERATELY UNSTABLE PRE-FRONTAL
ENVIRONMENT THIS AFTERNOON. AS EARLIER MENTIONED...SREF PROB FOR
CAPES EXCEEDING 2000 J/KG RAMP UP QUICKLY IN THE 15-18Z TIMEFRAME
ALONG AND EAST OF A LINE FROM NEAR KJST...TO KUNV AND KELM.
SHEAR APPEARS TO BE LACKING FOR WIDESPREAD SEVERE WEATHER...BUT
SOME STORMS WILL AT LEAST BE MARGINAL WITH AN ISOLATED THREAT OF
SEVERE WIND GUSTS...ESPECIALLY ACROSS THE SOUTHERN QUARTER TO
THIRD OF CENTRAL PA. BEST CHC STILL APPEARS TO BE ACROSS THE
LOWER SUSQ VALLEY DURING THE MID AFTERNOON TO EARLY EVENING.
MAX TEMPS THIS AFTERNOON WILL VARY FROM ONLY NEAR 70F ACROSS THE
NORTHWEST MOUNTAINS...TO THE UPPER 80S IN THE SE ZONES. DEWPOINTS
WILL MAKE FOR ONE LAST VERY UNCOMFORTABLE DAY BEFORE DRIER AIR
ARRIVES LATER TONIGHT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
EVENING SHRA/TSRA ACROSS THE SE COUNTIES WILL GIVE WAY TO CLEARING
SKIES LATE TONIGHT...AS COLD FRONT SETTLES SOUTH OF THE STATE AND
HIGH PRES/LOW PWAT AIR WORKS IN FROM THE WEST. THE CLEARING SKIES
AND LGT WIND SHOULD PROMOTE AREAS OF LATE NIGHT FOG IN THE VALLEYS
OF WESTERN PA.
ANY EARLY FOG SHOULD GIVE WAY TO MSUNNY AND MUCH LESS HUMID WX
SUNDAY...AS HIGH PRES PASSES NORTH OF PA. GEFS MEAN 925 TEMPS
SUPPORT MAX TEMPS FROM THE U60S OVR THE HIGH TERRAIN OF THE
ALLEGHENIES...TO THE U70S ACROSS THE LOWER SUSQ VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BULK OF MED RANGE GUIDANCE INDICATES A CLOUDIER AND PERHAPS
SHOWERY MON/TUE THAN WAS EARLIER THOUGHT...AS SHORTWAVE AND ASSOC
WEAK WAVE OF LOW PRES SLIDES JUST SOUTH OF PA. TIMING OF THIS
FEATURE IN GEFS OUTPUT SUGGESTS THE BEST CHANCE FOR A FEW -SHRA
WILL COME LATE MONDAY INTO EARLY TUESDAY ACROSS SOUTHERN PA.
FAIRLY GOOD AGREEMENT LATE WEEK AMONGST MED RANGE MDLS...ALL OF
WHICH TRACK A DEEPENING SFC LOW WEST OF PA THRU THE GRT LKS.
TRAILING COLD FRONT AND ASSOC SHOWER THREAT IS LIKELY TO COME
THRU CENTRAL PA THURSDAY.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
LINE OF SHOWERS AND SCT TSTMS OUTRAN ITS UPPER LEVEL SUPPORT AND
HAS WEAKENED OVER THE PAST SEVERAL HOURS /05Z-08Z/ AS IT PUSHED
ACROSS THE NW MTNS. MODELS INDICATE CONVECTION SHOULD CONTINUE TO
DISSIPATE DURING THE PRE-DAWN HOURS. SO IMPACTS FOR REMAINDER OF
THE OVERNIGHT SHOULD BE LIMITED TO AREAS OF FOG AND LOW CLOUDS
MAINLY ACROSS THE SUSQ VALLEY FROM KLNS-KMDT-KIPT...WHERE IFR
CONDITIONS WILL BECOME MORE COMMON.
REDUCTIONS FROM FOG/LOW CLOUDS WILL PERSIST INTO THE MID MORNING
ACROSS THE EAST...BUT CONDITIONS SHOULD EVENTUALLY RETURN TO VFR
BY LATE MORNING. ELSEWHERE...MID-HIGH CLOUDS SHOULD PRECLUDE ANY
MAJOR REDUCTIONS...WITH JUST SCT MVFR FOG POSS.
COLD FRONT APPROACHES AFTER SUNRISE AND SLOWLY CROSSES THE REGION
THROUGH THE DAY. EXPECT SHOWERS WITH INTERMITTANT RESTRICTIONS TO
WORK SOUTHEASTWARD AND TRANSITION INTO SHOWERS AND A FEW BROKEN
LINES OF TSRA. BIGGEST IMPACTS WILL BE FROM 12Z INTO THE MID/LATE
MORNING AROUND KBFD...LATE MORNING THROUGH MID AFTERNOON IN THE
CENTRAL MTNS FROM KJST-KAOO- KUNV- KIPT...AND AFTER 18Z IN THE
LOWER SUSQ NEAR KMDT-KLNS. CONDITIONS IMPROVE BEHIND THE
FRONT...THOUGH MVFR CIGS COULD LINGER IN THE WESTERN HIGHER
TERRAIN.
CLEARING SKIES AND TRAPPED MOISTURE COULD BRING REDUCTIONS TO
CIGS/VSBYS LATER TONIGHT INTO SUNDAY MORNING.
OUTLOOK...
SUN...AM FOG POSS.
MON...PATCHY AM VALLEY FOG POSS.
TUE...CHC SHOWERS/TSTMS.
WED...SCT SHOWERS/TSTMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/GARTNER
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
330 PM CDT SAT SEP 6 2014
.DISCUSSION...
COLD FRONT LOCATED JUST SOUTH OF A BOWLING GREEN...CLARKSVILLE TO
DYERSBURG LINE. SCATTERED ACTIVITY IS ORIENTED IN NEARLY LINEAR
FASHION SW-NE ACROSS THE MID STATE. THE ACTIVITY IS MOVING RATHER
SLOWLY TOWARD THE SOUTH SOUTHEAST. MID LEVEL FLOW IS RATHER
UNPRONOUNCED AS THE WESTERLIES HAVE NOT YET FULLY DESCENDED
SOUTHWARD ACROSS THE AREA. AT ANY RATE...LATEST HRRR SHOWS THAT THE
CURRENT ACTIVITY WILL HOLD TOGETHER THROUGH THIS EVENING AS IT MOVES
ACROSS SOUTHERN AREAS OF THE MID STATE. THEN LATER TONIGHT...AN
IMPULSE WITHIN THE WESTERLY FLOW WILL MOVE TOWARD THE AREA AND WE
COULD SEE SOME ADDITIONAL DEVELOPMENT. POPS FOR TONIGHT ARE LOOKING
LIKE 30-40 PERCENT SOUTH AND 20 PERCENT ACROSS THE NORTH.
COULD SEE SOME LATE NIGHT PATCHY FOG DEVELOPMENT ACROSS EASTERN
AREAS. DEWPOINT DEPRESSIONS SHOULD REMAIN RATHER LOW ACROSS THAT
AREA.
ON SUNDAY...JUST ENOUGH MOISTURE WILL HANG ON ACROSS THE PLATEAU TO
WARRANT A SLIGHTLY CHANCE OF SHOWERS. OTW...DRIER AIR TO MOVE IN
WITH NO PRECIP EXPECTED.
SUNDAY NIGHT AND MONDAY NIGHT LOOK DRY AND COOLER. THE CLOSE
PROXIMITY OF THE SFC HIGH CLOSE NEVER REALLY CLOSES IN ON THE MID
STATE. HOWEVER...IT DOES LOOK LIKE LOWER 60S TO UPPER 50S FOR LOWS.
MONDAY WILL FEATURE A MOSTLY SUNNY AND DRY DAY. SHOULD STILL SEE
HIGHS IN THE MID TO UPPER 80S AS THE UPPER TROUGHING IS RATHER BROAD
AND HEIGHTS STILL LOOK ELEVATED.
IN THE EXTENDED FCST...A COLD FRONT WILL GAIN STRENGTH AND WILL BE
ON APPROACH BY WEDNESDAY NIGHT. SHOULD SEE A NICE WARMUP IN ADVANCE
OF IT WITH HIGHS TUESDAY AND WEDNESDAY IN THE LOWER 90S. SHOWERS AND
TSTMS WILL BE A GOOD POSSIBILITY ON THURSDAY...A FEW STRONG STORMS
WILL BE POSSIBLE ALTHOUGH CAPE VALUES LOOK RATHER TEMPERED NOW.
SHOWER CHANCES TO PERSIST IN THE POST FRONTAL SECTOR AS THE LOWER
LEVELS FEATURE A REASONABLE SFC TO 850 MB HORIZONTAL FRONTAL
BOUNDARY DISPLACEMENT.
WE SHOULD RETURN TO DRIER AND NOTICEABLY COOLER WEATHER FOR FRIDAY
AND SATURDAY. THE FRONTAL BOUNDARY WILL STALL JUST NORTH OF THE GULF
COAST AS UPPER LEVEL W-E RIDGING STUBBORNLY HOLDS ACROSS THAT
AREA.
BY THE END OF THE EXTENDED...WE SHOULD SEE PLEASANT EARLY FALL
WEATHER WITH LOWS UPPER 40S TO LOWER 50S AND HIGHS JUST 70 TO 75
WITH LOW HUMIDITY.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 68 85 63 88 / 30 10 10 10
CLARKSVILLE 64 83 58 86 / 20 10 10 05
CROSSVILLE 66 80 60 83 / 30 20 10 10
COLUMBIA 68 86 64 89 / 30 10 10 05
LAWRENCEBURG 67 86 64 89 / 30 20 10 05
WAVERLY 66 84 60 87 / 20 10 10 05
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
635 PM CDT SUN SEP 7 2014
.AVIATION...
/00Z TAFS/
Thunderstorm outflow boundary will move through KSJT around 0030Z,
temporarily shifting winds to the south with gusts to 20 KTS.
Thunderstorms will be in the vicinity until 2Z. With low levels of
the atmosphere remaining moist, stratus expected with MVFR CIGS late
tonight, beginning at climatologically favorable times and
scattering out mid to late Monday morning.
&&
.PREV DISCUSSION... /ISSUED 313 PM CDT SUN SEP 7 2014/
SHORT TERM...
(Tonight and tomorrow)
The quasi-stationary front is currently analyzed very near the
southern border of the CWA, roughly along a line from Sheffield, to
Rock Springs, to San Antonio. Skies cleared by midday across the
I-10 corridor, allowing temperatures to warm into the mid 80s.
MLCAPE values around 1000-1500 J/kg are present from Ozona to
Junction per the RAP Mesoanalysis, but CINH is no longer a concern
in this area. Scattered showers and thunderstorms have developed in
the vicinity of this boundary and will move to the northwest during
the afternoon and evening hours. Rain chances tonight will primarily
be limited to locations south of a Sterling City to Brownwood line.
The primary concern will be locally heavy rainfall given the slow
storm motions and precipitable water values around 1.75". This could
result in minor flooding, mainly in urban areas. Low temperatures
tonight should be in the upper 60s.
On Monday, we`ll maintain a moist airmass across West Central TX.
Precipitable water values are progged to remain at or above 1.60",
but the surface boundary is progged to wash out as southerly flow
resumes across the region. The loss of a low-level forcing mechanism
will limit rain chances. However, with temperatures warming into the
lower 90s, we should still see diurnal isolated convection across
the area. The best rain chances will be over the northwest Hill
Country, but isolated showers and thunderstorms will be included for
much of the area east of a Sonora, to San Angelo, to Sweetwater
line.
Johnson
LONG TERM...
(Tomorrow night through Sunday)
A cold front will bring a chance of showers and thunderstorms and
cooler temperatures for the latter part of the work week...
Above normal temperatures are forecast on Tuesday, with highs
ranging from the lower to mid 90s across the Interstate 10 corridor,
to the mid to upper 90s across the Big Country. Overnight lows will
be int he mid 70s. In the meantime, an upper level trough will move
into the Northern Rockies, and then eventually into the Northern
Plains, sending a cold front into the northern Big Country Wednesday
evening. Ahead of the cold front, compressional heating will result
in unseasonably hot temperatures on Wednesday. Highs will generally
be in the mid to upper 90s.
Models continue to have timing differences with regard to the
aforementioned cold front. Both the ECMWF and the GFS bring a front
into the Big Country Wednesdays night, then eventually slowly move
it through much of the rest of West Central Texas during the day
Thursday. Showers and thunderstorms are forecast to develop along
the front, with the best chance across the Big Country initially,
then better chances spreading south into much of the rest of the
area Thursday into Thursday night. High temperatures on Thursday
will be dependent on the timing of the front and any associated
rainfall. For now, the forecast reflects highs in the mid 80s across
the Big Country to the lower 90s across the Interstate 10 corridor.
Beyond Thursday, the GFS pushes the front through the area, while
the ECMWF dissipates the boundary, with a stronger cold front moving
through during the day on Friday. For now, the forecast was geared
toward the faster GFS solution, with PoPs decreasing from north to
south Friday. If the ECMWF solution were to verify, higher PoPs
would linger into Friday/Friday night. Highs on Friday were trended
down, given the expected cloud cover and cold air advection. Highs
will range from the lower 70s in the Big Country to near 80 along
the Interstate 10 corridor. These temperatures may eventually need
to be trended down a bit. A slow warm up is forecast into next
weekend.
Daniels
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 66 91 71 96 75 / 10 10 5 5 5
San Angelo 67 92 71 96 75 / 20 10 5 5 5
Junction 68 90 71 95 74 / 20 20 10 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
04
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1143 PM CDT FRI SEP 5 2014
.DISCUSSION...
SEE 06Z AVIATION DISCUSSION.
&&
.AVIATION...
00Z MODELS HAVE COME IN A BIT MORE MOIST THAN THE 18Z RUN. PWATS
ARE PROGGED TO INCREASE SAT MORNING TO BETWEEN 1.90 AND 2.10
INCHES. A STRONG UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE
REGION ON SAT AFTN AS WELL. CONVECTIVE TEMPS ARE NEAR 86 ALONG THE
COAST TO 89 WELL INLAND. BOTH THE RAP AND HRRR SHOW CONVECTION
DEVELOPING AROUND 16Z AND EXPANDING IN COVERAGE THROUGH THE EARLY
AFTN. WILL CARRY VCTS FOR ALL TAF SITES BEGINNING AT 12Z NEAR THE
COAST...16Z CENTRAL ZONES AND AROUND 19-20Z WELL INLAND. A WEAK
BOUNDARY WILL APPROACH THE NORTHERN TAF SITES AROUND 06Z. 43
&&
.PREV DISCUSSION... /ISSUED 940 PM CDT FRI SEP 5 2014/
UPDATE...
SEE DISCUSSION FOR EVENING UPDATE.
DISCUSSION...
SHOWERS AND THUNDERSTORMS HAVE COME TO AN END THIS EVENING.
FORECAST SOUNDINGS FOR TOMORROW DON`T LOOK TO FAVORABLE FOR RAIN
CHANCES WITH AVERAGE MOISTURE AND LOW K INDEX VALUES. UPPER LEVEL
WINDS ALSO SHOW A LIGHT CONFLUENT PATTERN. AT 500MB THOUGH A
POCKET OF VORTICITY IS FORECASTED TO BREAK AND WASH OVER THE COAST
TOMORROW. FORECAST SOUNDINGS ALSO SHOW PLENTY OF INSTABILITY. HIGH
RES TEXAS TECH WRF AND RAP SHOWS COVERAGE INCREASING TOMORROW
AFTERNOON. THINK CHANCE POPS ARE THE WAY TO GO GIVEN THE INSTABILITY
IN FORECAST SOUNDINGS. CURRENT FORECAST HAS THIS COVERED. NO
UPDATE REQUIRED AT THIS TIME. 23
PREV DISCUSSION... /ISSUED 630 PM CDT FRI SEP 5 2014/
DISCUSSION...
A FAIRLY DEEP UPPER LEVEL RIDGE WILL REMAIN OVER SE TX FOR MOST
OF THE UPCOMING FORECAST PERIOD. A WEAKNESS IN THE RIDGE WILL MOVE
OVER SE TX FROM THE EAST AS A COLD FRONT DROPS SOUTHWARD TOWARD
THE FORECAST AREA. THIS WILL HELP KEEP SCATTERED THUNDERSTORM
CHANCES IN PLACE THROUGH SUNDAY. THE RIDGE WILL BUILD AGAIN
OVERHEAD THROUGH MID WEEK. TOWARD THE END OF THE WORK WEEK...A
STRONGER COLD FRONT MAY APPROACH THE AREA FROM THE NORTH.
MODEL FORECAST SOUNDINGS SHOW A SIMILAR SETUP FOR WHAT OCCURRED
TODAY FOR SATURDAY. WITH NO CAP...PW/S NEAR 2 INCHES...AND
FORECAST CAPE VALUES OF 3000 TO 3500...EXPECT THAT ISOLATED STRONG
THUNDERSTORMS WILL BE AGAIN POSSIBLE. THE MAIN THREAT WILL BE
STRONG GUSTY WINDS IN EXCESS OF 40 MPH...FREQUENT CLOUD-TO-GROUND
LIGHTNING...AND LOCALLY HEAVY RAINFALL. THE HIGH RESOLUTION ARW
AND NMM BOTH FORECAST THE COLD FRONT TO APPROACH THE NORTHERN
COUNTIES DURING THE EVENING. THIS MAY HELP TO KEEP AT LEAST
ISOLATED STORMS ACROSS THE FORECAST AREA SATURDAY NIGHT. THE
GLOBAL MODELS DO NOT PUSH THE FRONT ALL THE WAY THROUGH THE AREA
ON SUNDAY AND THEN MOVE IT BACK NORTH LATE SUNDAY INTO MONDAY.
THIS SHOULD KEEP SCATTERED STORMS ON SUNDAY AND ISOLATED CHANCES
ON MONDAY.
FOR TUESDAY AND WEDNESDAY THE RIDGE WILL LIKELY KEEP RAIN CHANCES
TO A MINIMUM. THE GFS AND ECMWF THEN DIFFER FOR THURSDAY...WITH
THE GFS FASTER WITH THE APPROACH OF THE NEXT COLD FRONT THURSDAY
EVENING. WOULD LIKE TO SEE A BIT BETTER MODEL CONSISTENCY...PLUS
FELT THAT THE SLOWER ECMWF MAY BE THE BETTER MODEL GIVEN THE UPPER
LEVEL PATTERN. BOTH MODELS HAVE SWITCHED FROM A NORTHWESTERLY FLOW
TO KEEP THE CENTER OF THE RIDGE A BIT FURTHER TO THE NORTH.
40
MARINE...
LIGHT ONSHORE WINDS WILL PERSIST THRU THE WEEKEND. PRESSURE
GRADIENT WILL BE WEAK ENOUGH TOWARD THE END OF THE WEEKEND AND
EARLY NEXT WEEK THAT WE`LL PROBABLY SEE A DISTINCT LANDBREEZE/
SEABREEZE CIRCULATION (BRIEF OFFSHORE FLOW LATE AT NIGHT & EARLY
MORNING BECOMING ONSHORE DURING THE DAY). OTHERWISE...SCATTERED
SHOWERS/TSTMS CAN BE EXPECTED EACH DAY. MOST FAVORED TIMES BETWEEN
2- 10AM. 47
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 95 74 94 74 / 30 40 30 30 20
HOUSTON (IAH) 75 92 75 93 74 / 30 40 30 30 20
GALVESTON (GLS) 82 90 80 89 78 / 30 30 20 30 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...23
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
228 PM EDT SAT SEP 6 2014
.SYNOPSIS...
A STRONG COLD FRONT WILL PUSH THROUGH OUR AREA TODAY AND
TONIGHT...HELPING TO IGNITE SCATTERED TO NUMEROUS SHOWERS AND
STORMS. THIS FRONT WILL STALL SOUTH OF THE REGION THROUGH EARLY
NEXT WEEK...KEEPING CLOUDS ALONG WITH THE THREAT FOR SHOWERS...BUT
COOLER TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1130 AM EDT SATURDAY...
BROAD CYCLONIC UPPER LEVEL FLOW EXISTS FROM HUDSON BAY REGION OF
CANADA SOUTHWARD INTO THE GREAT LAKES AND NEW ENGLAND. EMBEDDED
SHORT WAVE TROF WILL MOVE EAST FROM ONTARIO INTO QUEBEC TODAY WITH
RIBBON OF VORTICITY TRAILING SOUTHWEST THROUGH THE GREAT LAKES AND
INTO THE OHIO VALLEY. AT THE SURFACE A COLD FRONT EXTENDED FROM
LAKE ONTARIO...SOUTHWEST THROUGH THE OHIO VALLEY AND INTO THE MID
SECTION OF THE COUNTRY...SURFACE HIGH PRESSURE REPLACING AREAS
UPSTREAM OF THE FRONT WITH A MUCH COOLER DRIER AIRMASS...DEWPOINTS
IN THE 50S. EAST AND SOUTH OF THE FRONTAL BOUNDARY THE AIRMASS WAS
MORE TROPICAL LIKE WITH SURFACE DEWPOINTS IN THE LOWER 70S AND
DEEPER MOISTURE PROFILES SUPPORTING PERCEPTIBLE WATER...PWAT...
VALUES BETWEEN 1.6 AND 2.0 INCHES.
THE SURFACE COLD FRONT IS PROGGED TO ADVANCE SOUTH AND EAST
TODAY...APPROACHING OUR FORECAST AREA LATE IN THE DAY...BUT NOT
ACTUALLY CROSSING THE FORECAST AREA AND PROVIDING ANY SORT OF
AIRMASS CHANGE UNTIL LATE TONIGHT AND SUNDAY. UNTIL THE FRONT
CROSSES THE AREA WE WILL CONTINUE TO BASK IN THE TROPICAL AIRMASS
WITH MUGGY CONDITIONS PERSISTING THROUGHOUT THE DAY...NOT VERY
COMFORTABLE FOR OUTDOOR WORK...BUT MORE CONDUCIVE FOR JUST SITTING
AROUND IN THE SHADE AND DRINKING ICE TEA. WHATEVER YOUR
CHOICE...AT SOME POINT YOU WILL LIKELY HEAR A RUMBLE OF THUNDER.
EVEN THOUGH THE COLD FRONT WILL NOT GET HERE UNTIL
TONIGHT...THERE IS AN OUTFLOW BOUNDARY FROM LAST NIGHTS STORM
ACTIVITY OVER THE OHIO VALLEY THAT IS MOVING SOUTHEAST AHEAD OF
THE ACTUAL COLD FRONT. THIS OUTFLOW EXTENDS FROM SOUTHERN
PENNSYLVANIA THROUGH CENTRAL WEST VIRGINIA AND INTO EASTERN
KENTUCKY THIS MORNING. THIS OUTFLOW WILL LIKELY BECOME THE FOCUS
FOR RE-DEVELOPMENT OF STORM ACTIVITY AS IN MOVES ACROSS THE
MOUNTAINS THIS AFTERNOON. NONE OF THE MODELS HANDLE THIS FEATURE
VERY WELL...BUT I THINK THE NAM PROBABLY HAS THE BEST PROGNOSIS
WITH DEEP COVECTION FIRING ALONG THIS BOUNDARY AS IT CROSSES THE
HIGHLANDS OF WV/VA EARLY THIS AFTERNOON...ACTIVITY BECOMING MORE
AGGRESSIVE AND INCREASE IN AREAL COVERAGE ALONG THE BOUNDARY AS
WE APPROACH THE PEAK HEATING PART OF THE DAY.
THE MORNING RNK SOUNDING WAS QUITE JUICY WITH PWAT VALUES OF 1.72
INCHES. CAPE WAS AROUND 1200 J/KG INCREASING TO 2000 WHEN WE
REACH A COVECTIVE TEMPERATURE IN THE LOWER 80S. MEAN WIND WAS FROM
260 AT ABOUT 12KTS...AND PROGGED TO INCREASE SLIGHTLY AS THE UPPER
LEVEL WINDS INCREASE PER THE APPROACHING UPPER LEVEL TROF. GIVEN
THIS VERY MOIST PROFILE AND LESS THAN MODEST WIND FLOW...THINK OUR
MAIN THREAT THIS AFTERNOON WILL BE THUNDERSTORMS CONTAINING VERY
HEAVY RAIN. WINDS ALOFT SHOULD KEEP THE STORMS MOVING ALONG AT A
GOOD ENOUGH PACE TO PREVENT NEED FOR A FLASH FLOOD WATCH...HOWEVER
A LITTLE CONCERNED THAT OUR SOUTHWESTERN CWA...FROM THE FAR
WESTERN NEW RIVER VALLEY INTO NORTHWEST NORTH CAROLINA MAY BE AN
AREA WHERE WINDS WILL BE A FEW KNOTS LIGHTER. STORMS IN THIS
PARTICULAR REGION WILL NOT ONLY BE MOVING SLOWER...BUT MAY HAVE A
TENDENCY TO TRAIN OVER THE SAME AREA PER THE OUTFLOW BOUNDARY
BECOMING MORE WEST-EAST ORIENTED. IF RADAR TRENDS BEGIN TO REFLECT
THIS SORT OF SCENARIO...A SHORT DURATION FLASH FLOOD WATCH MAY BE
NEED FOR PARTS OF THE FORECAST AREA.
EVEN THOUGH THE MAIN THREAT IS HEAVY RAIN...CAN`T RULE OUT SOME
ISOLATED SEVERE WEATHER TOO. THE MORE ROBUST STORMS THIS AFTERNOON
MAY TAP INTO A BIT MORE MOMENTUM FROM THE INCREASING WINDS
ALOFT. THIS WILL ALSO BE AIDED BY WATER LOADING FROM THE INTENSE
RAIN CORES INCREASING POTENTIAL FOR WET MICROBURSTS...SOMETHING WE
EXPERIENCED WITH A FEW OF THE STORMS THAT MOVED ACROSS THE AREA
LAST TUESDAY EVENING.
ATTM WILL MAINTAIN LIKELY THREAT FOR SHOWERS/STORMS WITH HEAVY
RAIN...THE GREATEST COVERAGE OVER THE MOUNTAINS THIS AFTERNOON AND
TRANSLATING INTO THE PIEDMONT THIS EVENING. TEMPERATURES WILL BE
ALL OVER THE PLACE...SPIKING INTO THE 80S...AROUND 90 PRIOR TO
SHOWER AND STORM DEVELOPMENT...THEN BECOMING INFLUENCED BY THE
THUNDERSTORM RAIN CORES WITH READINGS GETTING KNOCKED BACK INTO
THE 70S BEFORE THE END OF THE DAY. DEWPOINTS WILL REMAIN
HIGH...U60S/L70S...SO IT WILL REMAIN MUGGY THROUGHOUT THE DAY.
BY 12Z SUNDAY...THE SFC FRONT IS FORECAST TO BE IN CENTRAL NC...BUT
PRECIPITATION IN THE SOUTHEAST PORTION OF THE FORECAST AREA WILL
LIKELY BE SLOW TO END WITH THE SLOW MOVEMENT OF THE FRONT...ALONG
WITH GOOD UPPER LEVEL DIVERGENCE ASSOCIATED WITH A RR QUAD OF AN
UPPER LEVEL JET MOVING THROUGH THE EASTERN GREAT LAKES AND NEW
ENGLAND.
LOW CLOUDS AND AND LIGHT PRECIP WELL TO THE NORTH OF THE BOUNDARY
WILL BE POSSIBLE AS WEDGE BEGINS TO BUILD PER HIGH PRESSURE MOVING
INTO NEW ENGLAND AND THE STABLE AIR TRYING TO WORK ITS WAY DOWN
THE EASTERN SEABOARD...A NORTHEAST WIND DEVELOPING ALONG AND EAST
OF THE APPALACHIANS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
AS OF 330 AM EDT SATURDAY...
OVERALL LOOKS LIKE A DAMP/WEDGE PATTERN FOR US THIS PERIOD.
MODELS ARE DIFFERING ON STRENGTH/POSITION OF A SFC LOW OVER THE SE
COAST SUN-TUE...BUT PER TRENDS/WPC GUIDANCE THE 00Z ECMWF/GFS SEEM
IN THE BALL PARK ON THIS SYSTEM. DIFFERENCES BETWEEN THESE MODELS
LIES IN THE QPF FIELD. THE GFS SEEMS INLAND TOO MUCH WITH QPF
MONDAY...THINKING A LOT OF DEEP MOISTURE WILL RESIDE ACROSS THE
COASTLINE WITH CONVECTION AND HENCE ROB SOME INFLOW INTO OUR NECK
OF THE WOODS.
FOR SUNDAY...THE SFC LOW WILL BE OVER GEORGIA/SOUTH CAROLINA WHILE
SFC HIGH STRETCHES FROM IA/MO ENE INTO WRN PA/NY. THE FLOW WILL TURN
MORE NE-E WITH INCREASING MOISTURE. SFC FRONT WILL BE SOUTHEAST OF
US ACROSS ERN NC...BUT SW FLOW ALOFT COMBINED WITH EASTERLY FLOW
WILL KEEP MOISTURE INFLOW INTO OUR REGION WITH HIGHER THREAT ALONG
THE SRN BLUE RIDGE SUNDAY AFTERNOON.
THE SFC HIGH MOVES QUICKLY NE AND SETS UP OVER NEW ENGLAND/SRN
QUEBEC SUNDAY NIGHT WITH FRONTAL SYSTEM REMAINING ALONG THE
COAST...WITH INVERTED TROUGH IN ERN TN. FAVORING A BETTER THREAT OF
SHOWERS EAST OF THE BLUE RIDGE SUNDAY NIGHT OVER INTO MONDAY
NIGHT...AS THE LOW SLIDES SLOWLY NWD ACROSS ERN NC THEN OFF THE VA
COAST. THE MODELS START TO SHOW DRIER AIR WORKING IN FROM THE WEST
TUESDAY MORNING...WITH DEEP MOISTURE SHIFTING OUT TO SEA. TUESDAY
WILL BE A DRIER DAY BUT MODELS SHOWING ANOTHER SYSTEM MOVING INTO
THE SRN PLAINS WITH UPPER SHORTWAVE SHIFTING ALONG THE NRN EDGE OF
THE RIDGE THAT REMAINS OVER THE GULF COAST INTO OUR REGION.
ATTM...NOT TOO IMPRESSED WITH PRECIP CHANCES TUESDAY WITH MAINLY
AFTERNOON/EVENING SHOWERS AND STORMS SCATTERED ACROSS THE BLUE RIDGE
AND ADJACENT COUNTIES WEST INTO THE WV MOUNTAINS.
TEMPS THIS PERIOD REMAIN TRICKY BUT WILL MOS SEEMS TO HAVE A DECENT
HANDLE ON HIGHS.
SUNDAY WILL BE TRANSITION DAY...BUT WILL SEE HIGHS MAINLY IN THE 70S
BEHIND THE FRONT WITH NE WINDS.
IF PRECIP IS MORE WIDESPREAD HIGHS MONDAY MAY NOT GET OUT OF THE 60S
IN THE EAST. FOR NOW I AM LEANING TOWARD THE MAV WHICH HAS HIGHS
FROM THE LOWER TO MID 70S IN THE WEST TO UPPER 70S/LOWER 80S ACROSS
THE FAR SW CWA...WITH SOME 60S IN BLUE RIDGE HIGHER TERRAIN AS WELL
AS THE ALLEGHANYS.
TUESDAY WILL BE WARMER WITH FLOW WEAKENING AND TURNING MORE NNW.
HIGHS WILL RANGE FROM THE MID TO UPPER 70S WEST TO LOWER 80S
SOUTHEAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
AS OF 400 PM EDT FRIDAY...
ON WEDNESDAY...A COLD FRONT SWEEPS ACROSS THE NORTHERN PLAINS
WITH A SURFACE WAVE TRACKING NORTHEAST TOWARDS THE GREAT LAKES. AS
THIS WAVE MOVES INTO ZONAL FLOW...IT WILL THEN TRACK OVER THE OHIO
VALLEY WEDNESDAY AFTERNOON/EVENING. THIS WAVE WILL KEEP BULK OF
THE STRONGER CONVECTION NORTH IN THE OHIO VALLEY. AS THIS WAVE
ENTERS THE OHIO VALLEY...THE WEDGE THAT WAS OVER THE MID ATLANTIC
REGION MONDAY AND TUESDAY WILL BEGIN TO ERODE. IF THIS WEDGE
REMAINS DRY WHILE IN THE AREA...IT SHOULD HAVE NO PROBLEMS ERODING
WEDNESDAY. IF THIS WEDGE HAS RAIN TO ENHANCE IT...IT MAY NOT CLEAR
THE AREA UNTIL LATE WEDNESDAY NIGHT. MODELS ARE PUSHING THIS COLD
FRONT ACROSS THE REGION ON THURSDAY. AS IN THE CASE WITH THE FRONT
EARLY IN THE WEEK...DOES THIS FRONT CLEAR THE FORECAST AREA OR
DOES IT STALL IN THE VICINITY. SINCE THIS FRONT IS TRYING TO TRACK
SOUTH IN ZONAL FLOW...THE POSSIBILITIES OF A SLOWER ARRIVAL
(FRIDAY AND/OR SATURDAY) OR HAVING THE FRONT STALL OVER THE REGION
IS HIGH. SINCE THIS IS POSSIBLE...WILL KEEP CHANCE POPS IN FOR
FRIDAY.
AREAS THAT HANG ON TO THE WEDGE WEDNESDAY WILL HAVE COOLER THAN
NORMAL TEMPERATURES. IF OUTSIDE THE WEDGE...AT OR ABOVE NORMAL
TEMPERATURES ARE LIKELY. THE WARMEST DAY OF THE WEEK SHOULD BE
THURSDAY...ESPECIALLY IF THE FRONT IS SLOW TO TRACK EAST.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 200 PM EDT SATURDAY...
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR ACROSS
THE AREA THROUGH 10PM THIS EVENING AS A COLD FRONT SLOWLY CROSSES
THE MOUNTAINS. INTENSE RAIN CORES WITH RAIN RATES OF 2-4 INCHES/HR
ANITICIPATED RESULTING IN WATER LOADING AND LOCALIZED STRONG
DOWNDRAFTS. POTENTIAL EXISTS FOR WET MICROBURST WINDS VCNTY OF
STRONGEST STORMS.
PASSAGE OF FRONT LATER TONIGHT WILL BRIND A WIND SHIFT...WINDS
BECOMING NORTHERLY...THEN NORTHEASTERLY BEHIND THE FRONT FOR
SUNDAY. NOT CONFIDENT AS TO HOW MUCH FOG/STRATUS WILL FORM TONIGHT
NOR HOW LONG IT WILL LINGER SUNDAY...BUT MODELS ARE SUGGESTING
WIDESPREAD IFR CONDITIONS WILL DEVELOP LATE TONIGH AND SUNDAY PER
LINGERING LOW LEVEL MOISTURE AND POTENTIAL FOR THIS MOISTURE TO
GET ENHANCED BY THE DEVELOPING NORTHEASTERLY WIND AND WEDGE OF
STABLE AIR DEVELOPING OVER AND EAST OF THE MOUNTAINS SUNDAY.
THE FRONT IS FORECAST TO STALL JUST SOUTH OF THE AREA SUNDAY AND
MONDAY...MAINTAINING CLOUD COVER AS WELL AS A THREAT FOR SHOWERS.
MEANWHILE LOW PRESSURE MOVING ALONG THE SOUTHEAST COAST WILL KEEP
OUR WINDS NE. THIS LOW IS PROGGED TO MOVE NORTHEAST ALONG THE
COAST MONDAY...MOVING OUT TO SEA BY LATE TUESDAY. UNTIL THIS AREA
OF LOW PRESSURE MOVES WELL OFF SHORE THE EXPECTATION IS FOR
LINGERING LOW LEVEL CLOUDINESS.
AFTER TUESDAY A RETURN TO SUMMER-LIKE CONDITIONS CAN BE EXPECTED
WITH DIURNAL SHOWERS AND STORMS. LATE NIGHT FOG IS ALSO LIKELY IN
THE MOUNTAIN VALLEYS. NEXT COLD FRONT IS FORECAST TO MOVE ACROSS
THE MIDWEST AND OHIO VALLEY WEDNESDAY WITH STRONG AREA OF LOW
PRESSURE MOVING INTO THE GREAT LAKES IMPACTING ROUTES THROUGH DTX-
ORD-MSP. THIS FRONT SHOULD REACH THE MID ATLANTIC REGION IN THE
THURSDAY/FRIDAY TIME FRAME.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PH
NEAR TERM...PH/PM
SHORT TERM...WP
LONG TERM...RCS
AVIATION...PM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
743 AM EDT SAT SEP 6 2014
.SYNOPSIS...
A STRONG COLD FRONT WILL PUSH THROUGH OUR AREA TODAY AND THIS
EVENING...HELPING TO IGNITE SCATTERED TO NUMEROUS SHOWERS AND
STORMS. THIS FRONT WILL STALL SOUTH OF THE REGION THROUGH EARLY NEXT
WEEK...KEEPING CLOUDS ALONG WITH THE THREAT FOR SHOWERS...BUT COOLER
TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 730 AM EDT SATURDAY...
OVERALL NEAR TERM FORECAST IS NOT BAD. UPDATED TO ADJUST POPS
DOWNWARD THIS MORNING. A FEW SHOWERS LINGERING OVER TOWARD BLF.
MAINLY DEALING WITH FOG IN THE WEST WHICH SHOULD BURN OFF HERE IN
BY 10-11 AM. STILL LOOKS LIKE MAIN INITIATION OF CONVECTION OCCURS
AFTER 16Z.
PREVIOUS VALID DISCUSSION...
A COLD FRONT ENTERS THE WESTERN PORTION OF OUR FORECAST AREA
AROUND 18Z...AND TRIES TO EXIT THE FAR SOUTHEAST PORTION OF OUR
FORECAST AREA BETWEEN 00Z- 06Z TONIGHT. AS THE BOUNDARY BECOMES
PARALLEL TO THE UPPER FLOW...ITS SOUTHWARD PROGRESSION WILL SLOW.
IN ADVANCE OF THIS FRONT...A WESTERLY COMPONENT TO THE LOW LEVEL
WINDS SHOULD ALLOW FOR SOME CLEARING TODAY AS WELL AS
DESTABILIZATION. FORECAST 0-6KM SHEAR VALUES INCREASE TO 20-25KTS
AFTER 21Z...SO SOME STORM ORGANIZATION IS EXPECTED. IN ADDITION TO
THE POTENTIAL FOR LOCALLY HEAVY RAINS WITH PWAT VALUES STILL 1-2
STANDARD DEVIATIONS ABOVE NORMAL TODAY...A SMALL DAMAGING WIND
THREAT EXISTS...WHICH WILL BE NOTED IN THE HAZARDOUS WEATHER
OUTLOOK.
COVERAGE OF SHOWERS AND STORMS SHOULD ONLY BE WIDELY SCATTERED IN
ADVANCE OF THE FRONT WITH A WEAK SOUTHWEST/WEST LOW LEVEL WIND...AND
GFS MAY BE OVERDONE WITH PRECIP COVERAGE AT 18Z. PLACED HIGHEST POPS
LATER IN THE DAY WHEN THE BETTER LOW LEVEL CONVERGENCE ARRIVES WITH
THE FRONT.
THE GFS MOS IS ONCE AGAIN SIGNIFICANTLY WARMER THAN MOST GUIDANCE
FOR HIGHS TODAY. WITH SOME CLEARING AND WEAK DOWNSLOPE WIND...HIGHS
TODAY SHOULD BE WARMER THAN VALUES ON FRIDAY. HOWEVER...WITH
INCREASING CLOUDS TODAY...USED A BLEND OF THE NAM/GFS MOS.
BY 12Z SUNDAY...THE SFC FRONT IS FORECAST TO BE IN CENTRAL NC...BUT
PRECIPITATION IN THE SOUTHEAST PORTION OF THE FORECAST AREA WILL
LIKELY BE SLOW TO END WITH THE SLOW MOVEMENT OF THE FRONT...ALONG
WITH GOOD UPPER LEVEL DIVERGENCE ASSOCIATED WITH A RR QUAD OF AN
UPPER LEVEL JET MOVING THROUGH THE EASTERN GREAT LAKES AND NEW
ENGLAND.
LOW CLOUDS AND AND LIGHT PRECIP WELL TO THE NORTH OF THE BOUNDARY
WILL BE POSSIBLE AS WEDGE BEGINS TO BUILD.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
AS OF 330 AM EDT SATURDAY...
OVERALL LOOKS LIKE A DAMP/WEDGE PATTERN FOR US THIS PERIOD.
MODELS ARE DIFFERING ON STRENGTH/POSITION OF A SFC LOW OVER THE SE
COAST SUN-TUE...BUT PER TRENDS/WPC GUIDANCE THE 00Z ECMWF/GFS SEEM
IN THE BALL PARK ON THIS SYSTEM. DIFFERENCES BETWEEN THESE MODELS
LIES IN THE QPF FIELD. THE GFS SEEMS INLAND TOO MUCH WITH QPF
MONDAY...THINKING A LOT OF DEEP MOISTURE WILL RESIDE ACROSS THE
COASTLINE WITH CONVECTION AND HENCE ROB SOME INFLOW INTO OUR NECK
OF THE WOODS.
FOR SUNDAY...THE SFC LOW WILL BE OVER GEORGIA/SOUTH CAROLINA WHILE
SFC HIGH STRETCHES FROM IA/MO ENE INTO WRN PA/NY. THE FLOW WILL TURN
MORE NE-E WITH INCREASING MOISTURE. SFC FRONT WILL BE SOUTHEAST OF
US ACROSS ERN NC...BUT SW FLOW ALOFT COMBINED WITH EASTERLY FLOW
WILL KEEP MOISTURE INFLOW INTO OUR REGION WITH HIGHER THREAT ALONG
THE SRN BLUE RIDGE SUNDAY AFTERNOON.
THE SFC HIGH MOVES QUICKLY NE AND SETS UP OVER NEW ENGLAND/SRN
QUEBEC SUNDAY NIGHT WITH FRONTAL SYSTEM REMAINING ALONG THE
COAST...WITH INVERTED TROUGH IN ERN TN. FAVORING A BETTER THREAT OF
SHOWERS EAST OF THE BLUE RIDGE SUNDAY NIGHT OVER INTO MONDAY
NIGHT...AS THE LOW SLIDES SLOWLY NWD ACROSS ERN NC THEN OFF THE VA
COAST. THE MODELS START TO SHOW DRIER AIR WORKING IN FROM THE WEST
TUESDAY MORNING...WITH DEEP MOISTURE SHIFTING OUT TO SEA. TUESDAY
WILL BE A DRIER DAY BUT MODELS SHOWING ANOTHER SYSTEM MOVING INTO
THE SRN PLAINS WITH UPPER SHORTWAVE SHIFTING ALONG THE NRN EDGE OF
THE RIDGE THAT REMAINS OVER THE GULF COAST INTO OUR REGION.
ATTM...NOT TOO IMPRESSED WITH PRECIP CHANCES TUESDAY WITH MAINLY
AFTERNOON/EVENING SHOWERS AND STORMS SCATTERED ACROSS THE BLUE RIDGE
AND ADJACENT COUNTIES WEST INTO THE WV MOUNTAINS.
TEMPS THIS PERIOD REMAIN TRICKY BUT WILL MOS SEEMS TO HAVE A DECENT
HANDLE ON HIGHS.
SUNDAY WILL BE TRANSITION DAY...BUT WILL SEE HIGHS MAINLY IN THE 70S
BEHIND THE FRONT WITH NE WINDS.
IF PRECIP IS MORE WIDESPREAD HIGHS MONDAY MAY NOT GET OUT OF THE 60S
IN THE EAST. FOR NOW I AM LEANING TOWARD THE MAV WHICH HAS HIGHS
FROM THE LOWER TO MID 70S IN THE WEST TO UPPER 70S/LOWER 80S ACROSS
THE FAR SW CWA...WITH SOME 60S IN BLUE RIDGE HIGHER TERRAIN AS WELL
AS THE ALLEGHANYS.
TUESDAY WILL BE WARMER WITH FLOW WEAKENING AND TURNING MORE NNW.
HIGHS WILL RANGE FROM THE MID TO UPPER 70S WEST TO LOWER 80S
SOUTHEAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
AS OF 400 PM EDT FRIDAY...
ON WEDNESDAY...A COLD FRONT SWEEPS ACROSS THE NORTHERN PLAINS
WITH A SURFACE WAVE TRACKING NORTHEAST TOWARDS THE GREAT LAKES. AS
THIS WAVE MOVES INTO ZONAL FLOW...IT WILL THEN TRACK OVER THE OHIO
VALLEY WEDNESDAY AFTERNOON/EVENING. THIS WAVE WILL KEEP BULK OF
THE STRONGER CONVECTION NORTH IN THE OHIO VALLEY. AS THIS WAVE
ENTERS THE OHIO VALLEY...THE WEDGE THAT WAS OVER THE MID ATLANTIC
REGION MONDAY AND TUESDAY WILL BEGIN TO ERODE. IF THIS WEDGE
REMAINS DRY WHILE IN THE AREA...IT SHOULD HAVE NO PROBLEMS ERODING
WEDNESDAY. IF THIS WEDGE HAS RAIN TO ENHANCE IT...IT MAY NOT CLEAR
THE AREA UNTIL LATE WEDNESDAY NIGHT. MODELS ARE PUSHING THIS COLD
FRONT ACROSS THE REGION ON THURSDAY. AS IN THE CASE WITH THE FRONT
EARLY IN THE WEEK...DOES THIS FRONT CLEAR THE FORECAST AREA OR
DOES IT STALL IN THE VICINITY. SINCE THIS FRONT IS TRYING TO TRACK
SOUTH IN ZONAL FLOW...THE POSSIBILITIES OF A SLOWER ARRIVAL
(FRIDAY AND/OR SATURDAY) OR HAVING THE FRONT STALL OVER THE REGION
IS HIGH. SINCE THIS IS POSSIBLE...WILL KEEP CHANCE POPS IN FOR
FRIDAY.
AREAS THAT HANG ON TO THE WEDGE WEDNESDAY WILL HAVE COOLER THAN
NORMAL TEMPERATURES. IF OUTSIDE THE WEDGE...AT OR ABOVE NORMAL
TEMPERATURES ARE LIKELY. THE WARMEST DAY OF THE WEEK SHOULD BE
THURSDAY...ESPECIALLY IF THE FRONT IS SLOW TO TRACK EAST.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 735 AM EDT SATURDAY...
FOG WILL BE DENSE AT BCB/LWB THIS MORNING...LIFTING TO MVFR/IFR BY
14-15Z...AND ALL VFR BY 15-16Z. OTHERWISE...EXPECTING AN SOMEWHAT
ACTIVE AFTERNOON THOUGH NOT WIDESPREAD CONVECTION...BUT ENOUGH
CONFIDENCE TO HAVE A FEW HOURS OF SHOWERS WITH VCTS IN THE TAFS.
WINDOW OF TSRA WILL BE IN THE 19-23Z TIME FRAME AND HAVE TEMPO
GROUPS OF 2 HOURS OR LESS FOR THUNDER AT ROA/BCB/BLF/LWB...LESS
COVERAGE FURTHER EAST.
THIS ACTIVITY WITH THE FRONT WEAKENS BY EARLY EVENING
00-02Z...WITH FOG DEVELOPING ONCE AGAIN. QUESTION WILL BE EXTENT
OF HIGHER CLOUDS. THINK VALLEYS IN THE WEST WILL SINK AGAIN TO
IFR/LIFR OVERNIGHT...WHILE ELSEWHERE CAN EXPECT HIGH END IFR/LOW
END MVFR.
THE FRONT WILL BE STALLED JUST SOUTH OF THE AREA SUNDAY AND
MONDAY...MAINTAINING CLOUD COVER AS WELL AS A THREAT FOR SHOWERS.
MEANWHILE LOW PRESSURE MOVING ALONG THE SOUTHEAST COAST WILL KEEP
OUR WINDS NE. THIS LOW MOVES OUT BY TUESDAY WITH A RETURN TO MORE
DIURNAL SHOWERS AND STORMS. WITH WEDGE IN PLACE SUN-MON THINK SUB
VFR IS HIGHER ESPECIALLY FROM BCB/ROA/LWB AND EAST. WEDGE BREAKS
TUESDAY SO EXPECT VFR OUTSIDE ANY SHOWERS/STORMS AND LATE NIGHT
FOG.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PH
NEAR TERM...PH/WP
SHORT TERM...WP
LONG TERM...RCS
AVIATION...PH/WP
AREA FORECAST DISCUSSION...CORRECTED
NWS BLACKSBURG VA
342 AM EDT SAT SEP 6 2014
.SYNOPSIS...
A STRONG COLD FRONT WILL PUSH THROUGH OUR AREA TODAY AND THIS
EVENING...HELPING TO IGNITE SCATTERED TO NUMEROUS SHOWERS AND
STORMS. THIS FRONT WILL STALL SOUTH OF THE REGION THROUGH EARLY NEXT
WEEK...KEEPING CLOUDS ALONG WITH THE THREAT FOR SHOWERS...BUT COOLER
TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM EDT SATURDAY...
A MOIST AIRMASS CONTINUES TO RESIDE OVER THE FORECAST AREA EARLY
SATURDAY MORNING...WITH THE 00Z SOUNDINGS FROM RNK AND GSO YIELDING
PWAT VALUES 150-160% OF NORMAL. ANOTHER MORNING OF PATCHY DENSE FOG
AND LOW CLOUDS CAN BE EXPECTED AND WILL COVER ANY PATCHY DENSE FOG
ISSUES WITH A SPECIAL WEATHER STATEMENT.
THE FOCUS TODAY WILL BE ON A COLD FRONT LOCATED FROM NORTHWEST OHIO
TO CENTRAL INDIANA INTO WESTERN KENTUCKY AT 06Z. SREF/GFS/NAM/ECMWF
ALL INITIALIZED THE LOCATION OF THIS BOUNDARY WELL...AND AGREE
THIS FEATURE ENTERS THE WESTERN PORTION OF OUR FORECAST AREA
AROUND 18Z...AND TRIES TO EXIT THE FAR SOUTHEAST PORTION OF OUR
FORECAST AREA BETWEEN 00Z-06Z TONIGHT. AS THE BOUNDARY BECOMES
PARALLEL TO THE UPPER FLOW...ITS SOUTHWARD PROGRESSION WILL SLOW.
IN ADVANCE OF THIS FRONT...A WESTERLY COMPONENT TO THE LOW LEVEL
WINDS SHOULD ALLOW FOR SOME CLEARING TODAY AS WELL AS
DESTABLIZATION. FORECAST 0-6KM SHEAR VALUES INCREASE TO 20-25KTS
AFTER 21Z...SO SOME STORM ORGANIZATION IS EXPECTED. IN ADDITION TO
THE POTENTIAL FOR LOCALLY HEAVY RAINS WITH PWAT VALUES STILL 1-2
STANDARD DEVIATIONS ABOVE NORMAL TODAY...A SMALL DAMAGING WIND
THREAT EXISTS...WHICH WILL BE NOTED IN THE HAZARDOUS WEATHER
OUTLOOK.
COVERAGE OF SHOWERS AND STORMS SHOULD ONLY BE WIDELY SCATTERED IN
ADVANCE OF THE FRONT WITH A WEAK SOUTHWEST/WEST LOW LEVEL WIND...AND
GFS MAY BE OVERDONE WITH PRECIP COVERAGE AT 18Z. PLACED HIGHEST POPS
LATER IN THE DAY WHEN THE BETTER LOW LEVEL CONVERGENCE ARRIVES WITH
THE FRONT.
THE GFS MOS IS ONCE AGAIN SIGNIFICANTLY WARMER THAN MOST GUIDANCE
FOR HIGHS TODAY. WITH SOME CLEARING AND WEAK DOWNSLOPE WIND...HIGHS
TODAY SHOULD BE WARMER THAN VALUES ON FRIDAY. HOWEVER...WITH
INCREASING CLOUDS TODAY...USED A BLEND OF THE NAM/GFS MOS.
BY 12Z SUNDAY...THE SFC FRONT IS FORECAST TO BE IN CENTRAL NC...BUT
PRECIPITATION IN THE SOUTHEAST PORTION OF THE FORECAST AREA WILL
LIKELY BE SLOW TO END WITH THE SLOW MOVEMENT OF THE FRONT...ALONG
WITH GOOD UPPER LEVEL DIVERGENCE ASSOCIATED WITH A RR QUAD OF AN
UPPER LEVEL JET MOVING THROUGH THE EASTERN GREAT LAKES AND NEW
ENGLAND.
LOW CLOUDS AND AND LIGHT PRECIP WELL TO THE NORTH OF THE BOUNDARY
WILL BE POSSIBLE AS WEDGE BEGINS TO BUILD.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
AS OF 330 AM EDT SATURDAY...
OVERALL LOOKS LIKE A DAMP/WEDGE PATTERN FOR US THIS PERIOD.
MODELS ARE DIFFERING ON STRENGTH/POSITION OF A SFC LOW OVER THE SE
COAST SUN-TUE...BUT PER TRENDS/WPC GUIDANCE THE 00Z ECMWF/GFS SEEM
IN THE BALL PARK ON THIS SYSTEM. DIFFERENCES BETWEEN THESE MODELS
LIES IN THE QPF FIELD. THE GFS SEEMS INLAND TOO MUCH WITH QPF
MONDAY...THINKING A LOT OF DEEP MOISTURE WILL RESIDE ACROSS THE
COASTLINE WITH CONVECTION AND HENCE ROB SOME INFLOW INTO OUR NECK
OF THE WOODS.
FOR SUNDAY...THE SFC LOW WILL BE OVER GEORGIA/SOUTH CAROLINA WHILE
SFC HIGH STRETCHES FROM IA/MO ENE INTO WRN PA/NY. THE FLOW WILL TURN
MORE NE-E WITH INCREASING MOISTURE. SFC FRONT WILL BE SOUTHEAST OF
US ACROSS ERN NC...BUT SW FLOW ALOFT COMBINED WITH EASTERLY FLOW
WILL KEEP MOISTURE INFLOW INTO OUR REGION WITH HIGHER THREAT ALONG
THE SRN BLUE RIDGE SUNDAY AFTERNOON.
THE SFC HIGH MOVES QUICKLY NE AND SETS UP OVER NEW ENGLAND/SRN
QUEBEC SUNDAY NIGHT WITH FRONTAL SYSTEM REMAINING ALONG THE
COAST...WITH INVERTED TROUGH IN ERN TN. FAVORING A BETTER THREAT OF
SHOWERS EAST OF THE BLUE RIDGE SUNDAY NIGHT OVER INTO MONDAY
NIGHT...AS THE LOW SLIDES SLOWLY NWD ACROSS ERN NC THEN OFF THE VA
COAST. THE MODELS START TO SHOW DRIER AIR WORKING IN FROM THE WEST
TUESDAY MORNING...WITH DEEP MOISTURE SHIFTING OUT TO SEA. TUESDAY
WILL BE A DRIER DAY BUT MODELS SHOWING ANOTHER SYSTEM MOVING INTO
THE SRN PLAINS WITH UPPER SHORTWAVE SHIFTING ALONG THE NRN EDGE OF
THE RIDGE THAT REMAINS OVER THE GULF COAST INTO OUR REGION.
ATTM...NOT TOO IMPRESSED WITH PRECIP CHANCES TUESDAY WITH MAINLY
AFTERNOON/EVENING SHOWERS AND STORMS SCATTERED ACROSS THE BLUE RIDGE
AND ADJACENT COUNTIES WEST INTO THE WV MOUNTAINS.
TEMPS THIS PERIOD REMAIN TRICKY BUT WILL MOS SEEMS TO HAVE A DECENT
HANDLE ON HIGHS.
SUNDAY WILL BE TRANSITION DAY...BUT WILL SEE HIGHS MAINLY IN THE 70S
BEHIND THE FRONT WITH NE WINDS.
IF PRECIP IS MORE WIDESPREAD HIGHS MONDAY MAY NOT GET OUT OF THE 60S
IN THE EAST. FOR NOW I AM LEANING TOWARD THE MAV WHICH HAS HIGHS
FROM THE LOWER TO MID 70S IN THE WEST TO UPPER 70S/LOWER 80S ACROSS
THE FAR SW CWA...WITH SOME 60S IN BLUE RIDGE HIGHER TERRAIN AS WELL
AS THE ALLEGHANYS.
TUESDAY WILL BE WARMER WITH FLOW WEAKENING AND TURNING MORE NNW.
HIGHS WILL RANGE FROM THE MID TO UPPER 70S WEST TO LOWER 80S
SOUTHEAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
AS OF 400 PM EDT FRIDAY...
ON WEDNESDAY...A COLD FRONT SWEEPS ACROSS THE NORTHERN PLAINS
WITH A SURFACE WAVE TRACKING NORTHEAST TOWARDS THE GREAT LAKES. AS
THIS WAVE MOVES INTO ZONAL FLOW...IT WILL THEN TRACK OVER THE OHIO
VALLEY WEDNESDAY AFTERNOON/EVENING. THIS WAVE WILL KEEP BULK OF
THE STRONGER CONVECTION NORTH IN THE OHIO VALLEY. AS THIS WAVE
ENTERS THE OHIO VALLEY...THE WEDGE THAT WAS OVER THE MID ATLANTIC
REGION MONDAY AND TUESDAY WILL BEGIN TO ERODE. IF THIS WEDGE
REMAINS DRY WHILE IN THE AREA...IT SHOULD HAVE NO PROBLEMS ERODING
WEDNESDAY. IF THIS WEDGE HAS RAIN TO ENHANCE IT...IT MAY NOT CLEAR
THE AREA UNTIL LATE WEDNESDAY NIGHT. MODELS ARE PUSHING THIS COLD
FRONT ACROSS THE REGION ON THURSDAY. AS IN THE CASE WITH THE FRONT
EARLY IN THE WEEK...DOES THIS FRONT CLEAR THE FORECAST AREA OR
DOES IT STALL IN THE VICINITY. SINCE THIS FRONT IS TRYING TO TRACK
SOUTH IN ZONAL FLOW...THE POSSIBILITIES OF A SLOWER ARRIVAL
(FRIDAY AND/OR SATURDAY) OR HAVING THE FRONT STALL OVER THE REGION
IS HIGH. SINCE THIS IS POSSIBLE...WILL KEEP CHANCE POPS IN FOR
FRIDAY.
AREAS THAT HANG ON TO THE WEDGE WEDNESDAY WILL HAVE COOLER THAN
NORMAL TEMPERATURES. IF OUTSIDE THE WEDGE...AT OR ABOVE NORMAL
TEMPERATURES ARE LIKELY. THE WARMEST DAY OF THE WEEK SHOULD BE
THURSDAY...ESPECIALLY IF THE FRONT IS SLOW TO TRACK EAST.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
AS OF 120 AM EDT SATURDAY...
UNDER A MOIST AIRMASS...AREAS OF LOCALLY DENSE FOG AND LIFR TO
MVFR CIGS AND VISIBILITIES WILL REDEVELOP EARLY THIS
MORNING...ESPECIALLY IN THE MOUNTAIN VALLEYS AND LOCATIONS THAT
RECEIVED RAINFALL ON FRIDAY.
DAYTIME HEATING WILL ALLOW FOG TO BURN OFF QUICKLY AFTER 9 AM
SATURDAY...POSSIBLY TAKING LONGER IN THE MOUNTAIN VALLEYS.
A COLD FRONT WILL MOVE THROUGH OUR AREA SATURDAY
AFTERNOON...BRINGING SHOWERS AND STORMS TO MUCH OF THE REGION.
THE COVERAGE OF THE PRECIPITATION WILL BE MORE WIDESPREAD THAN
WHAT HAS BEEN SEEN OVER THE PAST FEW DAYS. LOCALLY HEAVY RAIN
AND GUSTY WINDS WILL BE POSSIBLE UNDER THE STRONGER STORMS WITH
LOCAL IFR CONDITIONS UNDER THE STRONGER STORMS.
THIS FRONT WILL ADVANCE SOUTH OF OUR AREA BY SATURDAY
EVENING...AND A LOW LEVEL NORTH/NORTHEAST WIND DEVELOPING LATE
SATURDAY NIGHT WILL USHER IN LIFR TO IFR CLOUDS...ESPECIALLY AT
THE MOUNTAIN TAF SITES.
THE FRONT WILL BE STALLED JUST SOUTH OF THE AREA SUNDAY AND
MONDAY...MAINTAINING CLOUD COVER AS WELL AS A THREAT FOR SHOWERS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PH
NEAR TERM...PH
SHORT TERM...WP
LONG TERM...RCS
AVIATION...PH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1128 PM CDT FRI SEP 5 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 353 PM CDT FRI SEP 5 2014
AT 3 PM...A STRONG CANADIAN COLD FRONT EXTENDED FROM NEW BERLIN
WISCONSIN SOUTHWEST TO WEATHERFORD OKLAHOMA /KOJA/. TEMPERATURE
AHEAD OF THIS COLD FRONT RANGED FROM THE MID 80S TO MID 90S WITH
DEW POINTS IN THE 70S. MEANWHILE BEHIND THIS COLD FRONT...
TEMPERATURES WERE IN THE 60S AND 70S WITH DEW POINTS IN THE 50S.
A BAND OF 900 TO 700 MB FRONTOGENESIS IS GENERATING A BAND OF
SHOWERS ACROSS PARTS OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN. IN
ADDITION WITH THE RAP SHOWING MOST UNSTABLE CAPES UP TO 500 J/KG
AND SOME SLANTWISE CONVECTION...KEPT ISOLATED THUNDERSTORMS IN THE
FORECAST. WITH FAIRLY LIMITED MOST UNSTABLE CAPES AND UNFAVORABLE
0-3 KM OR 0-6 KM SHEAR...NOT ANTICIPATING ANY OF THESE
THUNDERSTORMS TO BECOME SEVERE. MEANWHILE FURTHER NORTHWEST
ACROSS SOUTHEAST MINNESOTA...700 TO 500 MB FRONTOGENESIS IS
PRODUCING ANOTHER BAND OF SHOWERS.
FOR EARLY THIS EVENING...THE RAP SHOWS THAT THE 2 BANDS OF
FRONTOGENESIS WILL MOVE QUICKLY SOUTHEAST OF THE FORECAST AREA BY
06.03Z. AS THIS OCCURS...THE SHOWERS AND ISOLATED THUNDERSTORMS
WILL MOVE OUT OF THE AREA. AS A RESULT...WENT WITH A QUICK
LOWERING OF THE PRECIPITATION PROBABILITIES FROM WEST TO EAST
ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND IN WESTERN
WISCONSIN SOUTH OF INTERSTATE 90 BETWEEN 05.23Z AND 06.03Z. IN
ADDITION TO THIS...THE CLOUDS SHOULD BE QUICKLY ON THE DECREASE.
FOR LATE TONIGHT...THE BUFKIT SOUNDINGS SHOW A SHALLOW LAYER /A
COUPLE OF HUNDRED FEET/ OF LIGHT WINDS WITH 10 TO 20 KNOTS ABOVE
300 FEET. THESE WINDS SHOULD MAKE IT UNFAVORABLE FOR THE
DEVELOPMENT OF FOG TONIGHT.
ON SATURDAY...BUFKIT SOUNDINGS SHOW VERY STEEP 900 TO 750 MB LAPSE
RATES /9-10 C/KM/ ACROSS THE AREA. THIS WILL ALLOW THE WIND GUSTS
TO CLIMB INTO THE 10 TO 20 KNOT RANGE. IN ADDITION...THIS WILL
ALLOW DRIER AIR FROM ALOFT TO MIX TO THE SURFACE. AS A RESULT...
LOWERED THE DEW POINTS INTO THE 45 TO 50 DEGREE RANGE. THIS STILL
MAY BE ON THE HIGH SIDE...BUT THE TREND IS IN THE RIGHT DIRECTION.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 353 PM CDT FRI SEP 5 2014
FROM LATE SATURDAY NIGHT INTO SUNDAY MORNING...THE LAYER OF LIGHT
WINDS ONCE AGAIN LOOK VERY SHALLOW. IN ADDITION...THE DEW POINTS
ARE SHOWING A SLOW RECOVERY. AS A RESULT...UNCERTAIN OF WHETHER
ANY VALLEY FOG WILL OCCUR OR NOT. SO JUST WENT WITH PATCHY FOG IN
THE RIVER VALLEY AND THE CRANBERRY BOGS OF CENTRAL WISCONSIN.
ON SUNDAY AFTERNOON...BUFKIT SOUNDINGS SHOW VERY STEEP 900 TO 750 MB
LAPSE RATES /8-10 C/KM/ ACROSS THE AREA. THIS WILL ALLOW DRIER
AIR FROM ALOFT TO MIX TO THE SURFACE. AS A RESULT...LOWERED THE
DEW POINTS INTO THE 45 TO 50 DEGREE RANGE.
FROM MONDAY AFTERNOON THROUGH WEDNESDAY...THE MODELS CONTINUE TO
SHOW THAT A SERIES OF SHORT WAVE TROUGHS WILL MOVE THROUGH THE
REGION. DUE TO RUN TO RUN MODEL INCONSISTENCIES...THE TIMING OF
THESE WAVES IS STILL A BIT UNCERTAIN...SO KEPT BROAD BRUSHED THE
PRECIPITATION CHANCES DURING THIS TIME FRAME. WITH MOST UNSTABLE
CAPES LESS THAN 750 J/KG...KEPT THE THUNDERSTORM CHANCES AS
ISOLATED. WHEN THE 0-3 KM TO 0-6 KM SHEAR DOES BECOME FAVORABLE
FOR THE DEVELOPMENT OF SUPERCELLS...THERE IS VERY LITTLE
INSTABILITY. AS A RESULT...NOT ANTICIPATING ANY SEVERE WEATHER.
ON WEDNESDAY NIGHT...A STRONG CANADIAN COLD FRONT WILL MOVE SOUTH
THROUGH THE FORECAST AREA. BEHIND THIS FRONT...850 MB TEMPERATURES
WILL FALL INTO THE 0 TO -4C RANGE AND REMAIN IN THIS RANGE INTO
THE WEEKEND. THIS IS NEARLY 2 STANDARD DEVIATIONS BELOW NORMAL.
IT CONTINUES TO LOOK LIKE...HIGH TEMPERATURES WILL BE AROUND 60
ON THURSDAY...AND ONLY IN THE 50S FOR FRIDAY. WHILE THERE IS
AGREEMENT IN THE ECMWF AND GFS ON THESE HIGH TEMPERATURES...THEY
ARE STILL RUNNING 10 DEGREES APART ON THE LOW TEMPERATURES FOR
THURSDAY NIGHT AND FRIDAY NIGHT. THE ECMWF HAS LOW TEMPERATURES
AROUND 40 AND THEY ARE AROUND 30 IN THE GFS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1128 PM CDT FRI SEP 5 2014
HIGH PRESSURE BUILDING INTO THE TAF SITES FROM THE NORTHERN PLAINS
OVER THE NEXT 24 HOURS WILL ALLOW A FEED OF DRY AIR TO CONTINUE...
RESULTING IN VFR CONDITIONS. THERE REMAINS A LITTLE CONCERN FOR
VALLEY FOG AT LSE THIS MORNING GIVEN THE TEMPERATURE/DEWPOINT
SPREAD OF 4 F AT 04Z. HOWEVER...A PERSISTENT 10 TO 20 KT NORTHWEST
BREEZE LOOKS TO EXIST RIGHT ABOVE LSE THROUGH THE ENTIRE EARLY
MORNING HOURS...STRONG ENOUGH TO PREVENT VALLEY FOG FORMATION.
THIS SAME BREEZE COULD RESULT IN A LITTLE GUSTINESS AT THE TAF
SITES DURING THE AFTERNOON...BUT NOT HIGH ENOUGH TO MENTION IN THE
TAFS AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
202 AM EDT MON SEP 8 2014
.PREV DISCUSSION... /ISSUED 823 PM EDT SUN SEP 7 2014/
UPDATE...
STALLED FRONTAL BOUNDARY REMAINS ACROSS CENTRAL GA THIS EVENING. A
WAVE OF LOW PRESSURE WILL SLOWLY MOVE EAST ALONG THE BOUNDARY
OVERNIGHT. NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE FOR
THE NEXT FEW HOURS...BUT SHOULD BEGIN TO DIMINISH BY MIDNIGHT.
DON`T EXPECT SHRA/TSRA TO COMPLETELY DIMINISH SO HAVE KEPT ISO/SCT
POPS IN FOR THE ENTIRE OVERNIGHT PERIOD. IN LOCALES WHERE IT
RAINED...LOW CLOUDS AND PATCHY FOG ARE POSSIBLE TOWARDS SUNRISE.
HAVE TRIED TO ORIENT POPS ACCORDING TO RADAR TRENDS. THE 19Z RUN
OF THE HRRR PEGGED THE CONVECTION PRETTY WELL...SO ALSO FOLLOWED
SUIT. TEMPS LOOKED GOOD.
PREV DISCUSSION... /ISSUED 735 PM EDT SUN SEP 7 2014/
PREV DISCUSSION... /ISSUED 308 PM EDT SUN SEP 7 2014/
SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
MODELS IN GOOD AGREEMENT TAKING THE SURFACE LOW OVER SOUTHEAST GA
AND MOVING IT UP THE COAST. THIS WILL KEEP A NORTHEAST SURFACE FLOW
OVER THE CWA THROUGH MONDAY NIGHT. CURRENT CONVECTION OVER THE CWA
WILL DISSIPATE THIS EVENING. THERE COULD BE AN ISOLATED
SHOWER/TSTORM JUST ABOUT ANYWHERE TONIGHT AND WILL MAINTAIN A 20 POP
ACROSS MOST OF THE CWA. A LITTLE HIGHER POPS ACROSS THE EXTREME
SOUTHEAST PART OF THE CWA TONIGHT DUE TO THE PROXIMITY OF THE
SURFACE LOW. AS THE SURFACE LOW PULLS TO OUR NORTHEAST...SLIGHTLY
DRIER AIR WILL MOVE INTO NORTH GA WITH THE DEEPEST MOISTURE SHIFTING
TO PARTS OF CENTRAL GEORGIA AND THIS IS WHERE THE HIGHEST POPS WILL
BE MONDAY AFTERNOON. ANY CONVECTION THAT DOES FORM WILL DIMINISH
MONDAY NIGHT.
17
LONG TERM /TUESDAY THROUGH SUNDAY/...
A WEAKENING FRONT ACROSS SOUTH GA AND A WEAK WEDGE PERSIST ACROSS
NORTHEAST GA ON TUESDAY. FOR THE REMAINDER OF THE WEEK...UPPER
LEVEL HIGH PRESSURE RETURNS ACROSS THE SOUTHEAST U.S. AND GA
REMAINS IN A MOIST TROPICAL AIR MASS. THIS WOULD SUPPORT ISOLATED
OR SCATTERED THUNDERSTORMS EACH DAY WITH MOSTLY A DIURNAL PATTERN.
BY FRIDAY A FRONT GETS PUSHED INTO NORTH GA AS A BROAD UPPER
TROUGH DEEPENS INTO THE GREAT LAKES. THE FRONT CONTINUES TO SINK
SOUTH ON SATURDAY...HOWEVER THE ECMWF SEEMS A BIT SLOWER WITH
THIS. OVERALL...IT LOOKS LIKE THERE WILL BE SOME DRYING ACROSS THE
NORTH BY THE END OF THE PERIOD. HAVE SHOWN ONLY A SLIGHT CHANCE OF
POPS ACROSS THE NORTH FOR SATURDAY...CHANCE ELSEWHERE.
41/16
&&
.AVIATION...
06Z UPDATE...
LATE NIGHT STORMS CONTINUE TO WEAKEN AND DIMINISH ACROSS THE ATL
METRO AREA. EXPECT IFR-MVFR CIGS TO DEVELOP BY 10Z AND SLOWLY
IMPROVE AFTER 13Z TODAY. CONVECTION WILL ONCE AGAIN FIRE AFTER
16Z...WITH BEST CHANCES 18-22Z...AND GENERALLY SOUTH OF THE ATL-
AHN LINE. FOR NOW HAVE GONE WITH THE PROB30 FOR ALL SITES...BUT
ONLY THE SOUTHERN SITES MAY HAVE THE TEMPO COME THE 12Z ISSUANCE.
EXPECT VRB WINDS AND LOW VFR CIGS WITH STORMS...AND PERIODS OF
HEAVY RAINFALL WILL REDUCE VSBYS. WINDS WILL GENERALLY BE EASTERLY
AT 8 KT OR LESS.
//ATL CONFIDENCE...06Z UPDATE...
HIGH CONFIDENCE ON ALL ELEMENTS EXCEPT FOR MEDIUM ON CIGS 10-14Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 84 66 87 67 / 30 20 20 20
ATLANTA 85 68 86 70 / 30 20 20 10
BLAIRSVILLE 81 62 83 62 / 40 20 20 20
CARTERSVILLE 87 67 88 68 / 30 20 20 10
COLUMBUS 89 71 90 71 / 60 30 30 10
GAINESVILLE 84 66 85 68 / 30 20 20 20
MACON 88 69 90 69 / 50 30 20 20
ROME 89 67 89 67 / 30 20 20 10
PEACHTREE CITY 86 66 87 67 / 40 20 20 10
VIDALIA 87 70 88 71 / 60 40 40 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...
AVIATION...
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
345 AM EDT MON SEP 8 2014
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 345 AM EDT MON SEP 8 2014
07Z SFC ANALYSIS SHOWS COOL AND DRY HIGH PRESSURE SPRAWLED OUT FROM
THE OHIO VALLEY THROUGH THE NEW ENGLAND STATES. GENERAL LOW PRESSURE
IS FOUND OVER THE DEEP SOUTH AND ALONG THE SOUTHEAST COAST. NOT FAR
FROM EAST KENTUCKY IS A STALLED FRONTAL BOUNDARY LURKING JUST TO THE
SOUTH. THIS HAS HELPED TO PREVENT THE DRY COMPONENT OF THE HIGH
PRESSURE FROM MAKING IT THROUGH ALL OF THE STATE AS DEWPOINTS ALONG
THE TENNESSEE BORDER ARE IN THE LOW AND MID 60S WHILE MID AND UPPER
50S EXIST TO THE NORTH. THESE NORTHERN SPOTS ARE ALSO ENJOYING
TEMPERATURES DOWN INTO THE MIDDLE AND UPPER 50S...PARTICULARLY IN THE
VALLEYS WHERE MOSTLY CLEAR SKIES HAVE ALLOWED FOR DECENT RADIATIONAL
COOLING BELOW THE THERMAL INVERSION. MEANWHILE...RIDGES AND LOCATIONS
TO THE SOUTH WITH HIGHER DEWPOINTS ARE SEEING TEMPERATURES A FEW
DEGREES MORE. A COUPLE LARGE PATCHES OF LOW CLOUDS ARE AFFECTING
SOUTHEAST KENTUCKY EARLY THIS MORNING HELPING TO DISRUPT THE FOG
FORMATION...THOUGH THERE WILL UNDOUBTEDLY BE PATCHY FOG...LOCALLY
DENSE...IN MANY VALLEY LOCATIONS GENERALLY CORRESPONDING TO THE
CLEAR SPOTS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH ANOTHER POCKET OF ENERGY
ROLLING EAST THROUGH GENERALLY FLAT FLOW TODAY...HELPING TO LOWER
HEIGHTS LOCALLY AND BRING SOME EXTRA LIFT TO THE AREA. THIS MOVES
THROUGH BY EVENING WITH CONTINUED RELATIVELY FAST AND NEARLY ZONAL
FLOW INTO THE DAY TUESDAY. LATE IN THE SHORT TERM PORTION OF THE
FORECAST HEIGHTS WILL CLIMB A NOTCH AHEAD OF A LARGE AND DEEPENING
TROUGH OVER THE ROCKY MOUNTAIN AND HIGH PLAINS STATES. WITH THE MODEL
SIMILARITIES HAVE GONE MAINLY WITH A BLEND OF THE HRRR AND NAM12 FOR
WX SPECIFICS DURING THE FIRST 12-18 HOURS AND THEN THE 00Z
ECMWF/NAM12 THROUGH TUESDAY.
SENSIBLE WEATHER WILL FEATURE A CONTINUED COOL AND DRY DAY ACROSS THE
FAR NORTHWEST PARTS OF THE AREA WHILE TO THE SOUTHEAST THERE WILL BE
MUCH MORE CLOUD COVER ALONG WITH A THREAT FOR SHOWERS THROUGH
THE MORNING. BY MIDDAY THUNDER CHANCES WILL PICK UP OWING TO BUILDING
INSTABILITY AND THE NEARBY FRONT BEING ACTED UPON BY THE PASSING MID
LEVEL SHORT WAVE. THE PCPN THREAT AND SOME OF THE CLOUD COVER WILL
RETREAT TO THE EAST LATER TONIGHT WITH ANOTHER NIGHT OF MINOR RIDGE
TO VALLEY TEMPERATURE DIFFERENCES AMIDST A NW TO SE STRIATION IN
DEWPOINTS. DUE TO THIS ANTICIPATE PATCHY VALLEY FOG AFTER MIDNIGHT
FOR MOST LOCATIONS...PARTICULARLY ONES THAT MANAGE TO SEE ANY RAIN
DURING THE DAY AND EVENING. TUESDAY WILL BE QUIET AND DRY...BUT A TAD
WARMER WHILE THE DEVELOPING LOW TO THE EAST STARTS TO LIFT NORTH
ALONG THE SOUTH EAST ATLANTIC SEABOARD.
STARTED WITH THE CONSSHORT FOR T...TD...AND WINDS...THROUGH THE
FIRST 24 HOURS FOLLOWED BY THE SUPERBLEND UNTIL 00Z WED. PER
USUAL...MADE MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS
TONIGHT. AS FOR POPS...ENDED UP CLOSER TO THE LOWER MAV GUIDANCE
TODAY AND SIMILAR TO A BLEND OF THE RATHER LOW NUMBERS THEREAFTER
THROUGH THE REMAINDER OF THE SHORT TERM FORECAST.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM EDT MON SEP 8 2014
THE MODELS REMAIN IN GOOD AGREEMENT IN THE LONG TERM...WITH A LARGE
RIDGE OF HIGH PRESSURE ALOFT INFLUENCING THE WEATHER OF EASTERN
KENTUCKY TO BEGIN THE PERIOD. DRY WEATHER SHOULD BE ON TAP TUESDAY
NIGHT INTO EARLY WEDNESDAY AFTERNOON AS HIGH PRESSURE REMAINS IN
CONTROL. HOWEVER...THIS UPPER RIDGE WILL BE DISPLACED AS DEEP AREA
OF LOW PRESSURE...BOTH ALOFT AND AT THE SURFACE...COMES TOGETHER
OVER THE NORTHERN PLAINS AND BEGINS TO PUSH ACROSS THE NORTHERN
MISSISSIPPI VALLEY ON WEDNESDAY. THE SURFACE COLD FRONT ASSOCIATED
WITH THIS POTENT SYSTEM WILL BRING UNSETTLED WEATHER TO THE AREA
WEDNESDAY NIGHT AND THURSDAY. THE PRIMARY CONCERN WITH THIS WEATHER
SYSTEM WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. THE MODELS
HAVE THE FRONT SLOWING DOWN AND NEARLY STALLING ACROSS OUR AREA ON
THURSDAY. SHOWERS AND STORMS ARE EXPECTED TO FIRE ALL ALONG THE
BOUNDARY AS LARGE AMOUNTS OF WARM MOIST AIR OFF THE GULF OF MEXICO
IS CARRIED NORTHWARD INTO THE BOUNDARY ON SOUTHERLY WINDS. THE BEST
CHANCE FOR RAIN LOOKS TO BE FROM LATE THURSDAY MORNING THROUGH LATE
THURSDAY AFTERNOON WHEN MOISTURE FLOW INTO THE FRONTAL ZONE IS AT
ITS PEAK. THERE WILL ALSO BE THE POTENTIAL FOR A FEW STRONG
THUNDERSTORMS ON THURSDAY AS THE FRONT MOVES THROUGH AS THERE WILL
BE STRONG DYNAMICS ASSOCIATED WITH THE BOUNDARY AND ITS PARENT UPPER
LEVEL SYSTEM. THUNDERSTORMS SHOULD THEN GIVE WAY TO RAIN SHOWER
BEHIND THE FRONT THURSDAY NIGHT AS THE COOLER AIR MOVES IN BEHIND
THE FRONT. THE FRONT IS EXPECTED TO EVENTUALLY CLEAR THE AREA LATE
THURSDAY NIGHT INTO EARLY FRIDAY MORNING...AS A LARGE RIDGE OF
CANADIAN HIGH PRESSURE PUSHES IT OFF TO OUR EAST. THIS AREA OF HIGH
PRESSURE WILL BRING A SIGNIFICANT PATTERN CHANGE TO THE MAJORITY OF
THE CONUS EAST OF THE ROCKY MOUNTAINS FROM FRIDAY ONWARD.
AFTER SLIGHTLY ABOVE NORMAL TEMPERATURES TUESDAY NIGHT AND
WEDNESDAY...A PERIOD OF UNSEASONABLE COOLING WILL BE OCCURRING.
HIGHS ON WEDNESDAY ARE EXPECTED TO TOP OUT IN THE MID TO UPPER 80S
AS SOUTHERLY WINDS BRING WARM MOIST AIR FROM THE GULF OF MEXICO INTO
THE REGION. ONCE THE FRONT ARRIVES ON THURSDAY...WIDESPREAD CLOUD
COVER AND PRECIPITATION WILL KEEP TEMPERATURES WELL BELOW
NORMAL...WITH HIGHS ONLY CLIMBING TO AROUND 80 BY THURSDAY
AFTERNOON. ONCE THE BOUNDARY HAS CLEARED THE AREA LATE THURSDAY
NIGHT...AN INVASION OF COOL AN DRY CANADIAN AIR WILL BEGIN TO OCCUR.
WITH WINDS SHIFTING TO THE NORTH BEHIND THE FRONT...TEMPERATURES
WILL BE HARD PRESSED TO CLIMB INTO THE MID 70S ON FRIDAY. THE COOL
WEATHER WILL THEN PERSIST THROUGH THE WEEKEND AS THE RIDGE OF HIGH
PRESSURE BECOMES MORE FIRMLY ESTABLISHED. HIGH TEMPERATURES ON
SATURDAY ARE EXPECTED TO ONLY CLIMB TO AROUND 70 WITH HIGHS ON
SUNDAY ONLY WARMING INTO THE LOW 70S. OVERNIGHT LOWS IN THE 50S ARE
EXPECTED AREA WIDE FRIDAY AND SATURDAY NIGHT AS THE COOL CANADIAN
AIR POURS INTO THE REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 230 AM EDT MON SEP 8 2014
A LOW CLOUD DECK IS HOLDING ON OVER FAR SOUTHEAST KENTUCKY WITH SOME
WESTWARD PUSH NOTED IN THE SATELLITE TRENDS. THESE CLOUDS ARE
GENERALLY IN THE MVFR RANGE FOR CIGS. HOWEVER...THEY ARE HELPING TO
KEEP THE FOG AT BAY FOR MANY OF THE SITES IN THE EAST THOUGH IT
CANNOT BE COMPLETELY RULED OUT...ESPECIALLY IF THERE ARE ANY BREAKS.
WILL CONTINUE THE FORECAST FOR LOWERING CIGS AND POORER AVIATION
CONDITIONS THROUGH DAWN. ISOLATED TO SCATTERED RAIN SHOWERS ARE
EXPECTED TO REDEVELOP...MAINLY EAST OF JKL...TOWARD MORNING
PERSISTING INTO THE DAY. AN ISOLATED THUNDERSTORM CANNOT BE RULED
OUT MONDAY AFTERNOON AND INTO THE EARLY EVENING HOURS...AS WELL. HAVE
ADDED A VCTS FOR THIS IN THE ALL THE TAFS EXCEPT SYM. WINDS THROUGH
THE PERIOD WILL BE LIGHT AND VARIABLE ACROSS THE FORECAST AREA.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
443 AM EDT MON SEP 8 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM EDT MON SEP 8 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT ZONAL FLOW
ALF ALONG THE CNDN BORDER. A SHRTWV RDG EMBEDDED IN THIS W-E FLOW IS
MOVING THRU THE UPR LKS EARLY THIS MRNG...SUPPORTING SFC HI PRES
OVER THE SE GREAT LKS. ACYC SW FLOW ARND THIS HI AND DRY AIRMASS
SHOWN ON LOCAL 00Z RAOBS...ESPECIALLY AT MPX WHERE THE 00Z PWAT IS
0.48 INCH OR 60 PCT OF NORMAL...ARE RESULTING IN MOCLR CONDITIONS
ACRS UPR MI. BUT HI CLDS ARE APRCHG WRN UPR MI IN ADVANCE OF A
SHRTWV MOVING E THRU THE NRN PLAINS IN THE SRN BRANCH FLOW. ANOTHER
SHRTWV WITHIN THE STRONGER NRN BRANCH IS PUSHING EWD THRU SRN
SASKATCHEWAN.
MAIN FCST CONCERNS IN THE SHORT TERM WL BE WHETHER AND IF THEN HOW
QUICKLY SHOWERS SPREAD INTO UPR MI IN ADVANCE OF UPSTREAM SHRTWVS.
TODAY...SRN BRANCH DISTURBANCE IN THE NRN PLAINS EARLY THIS MRNG IS
PROGGED TO MOVE E AND INTO NRN WI BY 00Z TUE. ALTHOUGH UPR MI WL BE
ON THE FAVORED CYC SIDE OF THE TRACK OF THIS DISTURBANCE...
PERSISTENT SW FLOW ARND SFC HI PRES MOVING INTO NEW ENGLAND WL
ADVECT DRIER AIR FM THE SW AND THE DIRECTION OF MPX. SO ALTHOUGH
PVA/H5-3 QVECTOR CNVGC AHEAD OF THE SHRTWV IS FCST TO IMPACT MAINLY
THE S HALF OF UPR MI...MODELS INDICATE AN ABSENCE OF ANY SGNFT H85-5
QVECTOR CNVGC. THIS SETUP SUGGESTS THE MAIN IMPACT WL BE THE HI CLDS
SPILLING E FM MN. SO EVEN THOUGH SOME MODELS GENERATE PCPN NEAR THE
WI BORDER AFTER 18Z...OPTED TO MAINTAIN GOING DRY FCST. FCST H85
TEMPS RANGING FM ABOUT 11C OVER THE E TO 13C OVER THE W AND MIXING
TO H8-85 AS OBSVD UPSTREAM YDAY SUPPORTS HI TEMPS IN THE MID/UPR
70S. SSW FLOW OFF LK MI WL BRING COOLER WX TO THE ERN CWA. THE
DAYTIME HEATING/MIXING AND H925 WINDS IN THE 20-30KT RANGE WL RESULT
IN GUSTY WINDS BY LATE MRNG. GIVEN THE FVRBL CONDITIONS FOR GUSTY
WINDS...BUMPED UP FCST GUSTS A COUPLE OF KTS ABV WIND GUST PROCEDURE
OUTPUT.
TNGT...UPR MI IS FCST TO BE DOMINATED BY DEEP LYR QVECTOR DVGC BTWN
DEPARTING SRN BRANCH SHRTWV THRU NRN LOWER MI AND NRN BRANCH
DISTURBANCE CROSSING NW ONTARIO. SO ALTHOUGH THE PERSISTENT SW FLOW
BTWN THE HI PRES MOVING INTO THE CNDN MARITIMES AND AN APRCHG COLD
FNT ATTENDANT TO THE NRN BRANCH SHRTWV WL BRING A RETURN OF HIER H85
THETA E INTO THE UPR LKS...LINGERING MID LVL DRY AIR BEST SHOWN BY
THE 00Z GFS FCST SDNGS WARRANTS KEEPING THE GOING DRY FCST. STEADY
SW WIND AND INCRSG LLVL MSTR THAT MAY RESULT IN SOME SC ESPECIALLY
OVER THE W HALF CLOSER TO THE HIER H85 THETA E WL RESULT IN WELL ABV
NORMAL MIN TEMPS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 441 AM EDT MON SEP 8 2014
THE MAIN THREATS THIS PERIOD WILL BE THE HEAVY RAIN TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT...STRONG NORTHERLY WINDS LATE WEDNESDAY
AFTERNOON THROUGH WEDNESDAY NIGHT ALONG LAKE SUPERIOR...AND A
PROLONGED PERIOD OF COOL WEATHER STARTING THURSDAY WITH NEAR OR
BELOW FREEZING TEMPERATURES ANTICIPATED LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING /COOLEST INLAND FROM THE GREAT LAKES/.
TUESDAY...
THE LAST DAY OF ABOVE NORMAL TEMPERATURES...OR EVEN NEAR NORMAL
TEMPERATURES FOR THE NEXT WEEK WILL BE TUESDAY. FAVORABLE S WINDS
OVER THE E HALF OF UPPER MI SHOULD ALLOW AREAS NEAR LAKE SUPERIOR TO
RISE INTO THE MID TO UPPER 70S...WITH LOW 70S COMMON ELSEWHERE. LOOK
FOR A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS OVER THE
W HALF OF THE CWA AS THE SFC TROUGH CONNECTING LOWS OVER CENTRAL
PLAINS AND HUDSON BAY SHIFTS ACROSS THE CWA. BROAD W TO SW FLOW
ALOFT WILL KEEP SWINGING DISTURBANCES ACROSS THE AREA AT 500MB.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...
MODELS ARE COMING INTO BETTER AGREEMENT FOR THE TRACK OF THE SFC LOW
EJECTING NE OUT OF THE CENTRAL PLAINS TUESDAY NIGHT. LOOK FOR THE
SFC LOW TO BE SET UP ACROSS S MN AND IA AT 06Z TO SHIFT OVER S
CENTRAL UPPER MI/NE WI/N LAKE MI BY MID AFTERNOON. THIS WILL BRING
WIDESPREAD RAIN TO THE REGION. WITH PW VALUES RISING TO 1.5-2IN
HEAVY RAIN IS A CONCERN. CURRENTLY HAVE 1.5 TO JUST OVER 2IN OF RAIN
FCST FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. KEPT THE SMALL
CHANCE OF THUNDERSTORMS ALONG LAKE MI WEDNESDAY. WITH THE TRACK OF
THE SFC LOW...AND STRONG HIGH PRESSURE SET UP OVER CENTRAL AND S
ALBERTA/SASKATCHEWAN...STRONG N WINDS OF 40-45MPH WILL BE POSSIBLE
LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...WITH THE
STRONGEST WINDS MOSTLY LIKELY ACROSS THE KEWEENAW PENINSULA. A WIND
ADVISORY MAY BE NEEDED FOR THE KEWEENAW PENINSULA. AS PREVIOUSLY
NOTED...EVEN IF WINDS DON/T QUITE REACH ADVISORY CRITERIA...TREES
COULD BE MORE SUSCEPTIBLE TO FALLING DUE TO THE SATURATED GROUND AND
PLENTY OF LEAVES ON THE TREES.
WEDNESDAY NIGHT THROUGH SUNDAY...
THE SFC LOW WILL SHIFT OVER ONTARIO AND QUEBEC WEDNESDAY
NIGHT...WITH THE SFC TROUGH LINGERING ACROSS UPPER MI INTO THURSDAY.
NW FLOW WILL BRING IN PLENTY OF COLD AIR BEHIND THE LOW...WITH
TEMPERATURES REMAINING WELL BELOW NORMAL THROUGH AT LEAST THE
UPCOMING WEEKEND. 850MB TEMPS OF -1C BY 18Z THURSDAY WILL RESULT IN
LAKE EFFECT RAIN WHICH WILL LINGER THROUGH FRIDAY AS A SECOND WAVE
AND TROUGH AXIS MORE ACROSS THE CWA THURSDAY NIGHT-FRIDAY.
HAVE ADDED THE POTENTIAL FOR NEAR OR BELOW FREEZING TEMPS INLAND
FROM THE GREAT LAKES...AND PRIMARILY OVER THE W HALF OF UPPER MI
LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING AS THE LARGE AREA OF
HIGH PRESSURE TO THE W BUILDS OVERHEAD WITH DECREASING CLOUDS. WINDS
WILL BECOME MORE W OR OUT OF THE S ON SATURDAY...EFFECTIVELY ENDING
OUR LAKE EFFECT CLOUDS OR SHOWERS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 123 AM EDT MON SEP 8 2014
EXPECT VFR CONDITIONS THIS FCST PERIOD. DAYTIME HEATING/MIXING WL
ALLOW FOR GUSTY WINDS TO 15-20 KT MON AFTN AND WINDS WILL STAY UP
THROUGH MON EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 AM EDT MON SEP 8 2014
FOG MAY CONTINUE TO BE A CONCERN INITIALLY OVER PORTIONS OF W AND
CENTRAL LAKE SUPERIOR. LAKE SUPERIOR WILL INITIALLY BE STUCK BETWEEN
EXITING HIGH PRESSURE OVER THE NEW ENGLAND STATES...AND A NEARING
TROUGH STRETCHING FROM NORTH DAKOTA THROUGH NORTHERN ONTARIO. LOOK
FOR THE TROUGH TO PUSH INTO LAKE SUPERIOR ON TUESDAY...WHILE A
STRONGER LOW ORGANIZES ACROSS THE CENTRAL PLAINS. EXPECT THE
DEEPENING LOW TO SHIFT NE ACROSS WI ON WEDNESDAY...AND ACROSS E
UPPER MI AND N LOWER MI LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING...BEFORE CONTINUING NE INTO QUEBEC ON THURSDAY. A PERIOD OF
N GALES WILL BE POSSIBLE LATE TUESDAY NIGHT INTO EARLY THURSDAY. IN
LARGE HIGH PRESSURE OVER S ALBERTA AND SASKATCHEWAN THURSDAY IS
EXPECTED TO DIVE ACROSS THE N AND CENTRAL PLAINS...WHILE BUILDING A
RIDGE ACROSS LAKE SUPERIOR ON THURSDAY NIGHT AND FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...07
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
333 AM EDT MON SEP 8 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM EDT MON SEP 8 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT ZONAL FLOW
ALF ALONG THE CNDN BORDER. A SHRTWV RDG EMBEDDED IN THIS W-E FLOW IS
MOVING THRU THE UPR LKS EARLY THIS MRNG...SUPPORTING SFC HI PRES
OVER THE SE GREAT LKS. ACYC SW FLOW ARND THIS HI AND DRY AIRMASS
SHOWN ON LOCAL 00Z RAOBS...ESPECIALLY AT MPX WHERE THE 00Z PWAT IS
0.48 INCH OR 60 PCT OF NORMAL...ARE RESULTING IN MOCLR CONDITIONS
ACRS UPR MI. BUT HI CLDS ARE APRCHG WRN UPR MI IN ADVANCE OF A
SHRTWV MOVING E THRU THE NRN PLAINS IN THE SRN BRANCH FLOW. ANOTHER
SHRTWV WITHIN THE STRONGER NRN BRANCH IS PUSHING EWD THRU SRN
SASKATCHEWAN.
MAIN FCST CONCERNS IN THE SHORT TERM WL BE WHETHER AND IF THEN HOW
QUICKLY SHOWERS SPREAD INTO UPR MI IN ADVANCE OF UPSTREAM SHRTWVS.
TODAY...SRN BRANCH DISTURBANCE IN THE NRN PLAINS EARLY THIS MRNG IS
PROGGED TO MOVE E AND INTO NRN WI BY 00Z TUE. ALTHOUGH UPR MI WL BE
ON THE FAVORED CYC SIDE OF THE TRACK OF THIS DISTURBANCE...
PERSISTENT SW FLOW ARND SFC HI PRES MOVING INTO NEW ENGLAND WL
ADVECT DRIER AIR FM THE SW AND THE DIRECTION OF MPX. SO ALTHOUGH
PVA/H5-3 QVECTOR CNVGC AHEAD OF THE SHRTWV IS FCST TO IMPACT MAINLY
THE S HALF OF UPR MI...MODELS INDICATE AN ABSENCE OF ANY SGNFT H85-5
QVECTOR CNVGC. THIS SETUP SUGGESTS THE MAIN IMPACT WL BE THE HI CLDS
SPILLING E FM MN. SO EVEN THOUGH SOME MODELS GENERATE PCPN NEAR THE
WI BORDER AFTER 18Z...OPTED TO MAINTAIN GOING DRY FCST. FCST H85
TEMPS RANGING FM ABOUT 11C OVER THE E TO 13C OVER THE W AND MIXING
TO H8-85 AS OBSVD UPSTREAM YDAY SUPPORTS HI TEMPS IN THE MID/UPR
70S. SSW FLOW OFF LK MI WL BRING COOLER WX TO THE ERN CWA. THE
DAYTIME HEATING/MIXING AND H925 WINDS IN THE 20-30KT RANGE WL RESULT
IN GUSTY WINDS BY LATE MRNG. GIVEN THE FVRBL CONDITIONS FOR GUSTY
WINDS...BUMPED UP FCST GUSTS A COUPLE OF KTS ABV WIND GUST PROCEDURE
OUTPUT.
TNGT...UPR MI IS FCST TO BE DOMINATED BY DEEP LYR QVECTOR DVGC BTWN
DEPARTING SRN BRANCH SHRTWV THRU NRN LOWER MI AND NRN BRANCH
DISTURBANCE CROSSING NW ONTARIO. SO ALTHOUGH THE PERSISTENT SW FLOW
BTWN THE HI PRES MOVING INTO THE CNDN MARITIMES AND AN APRCHG COLD
FNT ATTENDANT TO THE NRN BRANCH SHRTWV WL BRING A RETURN OF HIER H85
THETA E INTO THE UPR LKS...LINGERING MID LVL DRY AIR BEST SHOWN BY
THE 00Z GFS FCST SDNGS WARRANTS KEEPING THE GOING DRY FCST. STEADY
SW WIND AND INCRSG LLVL MSTR THAT MAY RESULT IN SOME SC ESPECIALLY
OVER THE W HALF CLOSER TO THE HIER H85 THETA E WL RESULT IN WELL ABV
NORMAL MIN TEMPS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 PM EDT SUN SEP 7 2014
MONDAY NIGHT INTO TUESDAY WILL BE THE TRANSITION PERIOD FROM THE
DRY AND RELATIVELY WARM HIGH PRESSURE DEPARTING THE AREA TO THE
MUCH COOLER AND WET PERIOD IN STORE FOR THE SECOND HALF OF THE WORK
WEEK. THE START OF THIS TRANSITION WILL BE A COLD FRONT EXTENDING
SOUTHWEST FROM A LOW NEAR HUDSON BAY. THIS FRONT WILL SLOWLY SHIFT
TO THE EAST OUT OF MINNESOTA ON MONDAY NIGHT AND INTO WESTERN LAKE
SUPERIOR AND THE WESTERN U.P. TUESDAY. EXPECT ISOLATED/SCATTERED
SHOWERS TO OCCUR ALONG THIS FRONT AS IT SLOWLY MOVES EAST ACROSS THE
U.P. LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT. DID CONTINUE TO
INCLUDE A SLIGHT CHANCE OF THUNDER ON THE EAST SIDE OF THE
FRONT/TROUGH DUE TO THE INSTABILITY INCREASING UNDER THE SOUTHERLY
FLOW DURING THE AFTERNOON BEFORE DIMINISHING IN THE EVENING.
THIS SLOW MOVING TROUGH WILL BE THE FOCUS FOR THE TRACK OF THE
STRONG LOW PRESSURE SYSTEM THAT WILL BE DEVELOPING IN THE CENTRAL
PLAINS ON TUESDAY AND THEN QUICKLY LIFTING NORTHEAST THROUGH THE
UPPER GREAT LAKES REGION WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT.
STILL SOME DIFFERENCES IN THE LOW TRACK BETWEEN THE OPERATIONAL
MEMBERS AND ITS LOCATION AT 00Z THURSDAY...BUT THE 00Z ECMWF OR 12Z
GEM RUNS SEEM TO BE A GOOD COMPROMISE WITH THE OTHER MODELS AND
ENSEMBLE MEMBERS. THIS CONSENSUS TRACKS A LOW-MID 990MB LOW FROM
SOUTHEAST MINNESOTA AT 12Z WEDNESDAY TO NORTHERN LAKE MICHIGAN BY
00Z THURSDAY AND INTO QUEBEC ON THURSDAY. 06Z GFS AND 00Z ECMWF
ENSEMBLE MEMBERS SUPPORT THAT IDEA AND AWAY FROM THE FASTER AND
FARTHER EAST SOLUTION SEEN ON THE 12Z GFS. WITH THAT IDEA IN
MIND...EXPECT A TRANSITION FROM THE LIGHTER PRECIP ASSOCIATED WITH
THE SURFACE TROUGH OVER WESTERN/CENTRAL U.P. ON TUESDAY NIGHT TO
WIDESPREAD RAIN LIFTING NORTHEAST ACROSS THE AREA ON WEDNESDAY.
WILL CONTINUE TO SHOW INCREASING POPS DURING THAT PERIOD AS THE
ISENTROPIC ASCENT PUSHES THROUGH THE AREA AND DECIDED UP THE
WEDNESDAY POPS TO DEFINITE VALUES ACROSS THE CWA. DID ADD A SMALL
POCKET OF THUNDER ALONG THE LAKE MICHIGAN BORDER WEDNESDAY WHERE THE
SURFACE LOW WILL TRACK AND POCKET OF ELEVATED INSTABILITY WOULD BE
LOCATED. AS THE LOW LIFTS NORTHEAST ON WEDNESDAY NIGHT...EXPECT THE
RAIN TO LINGER THE LONGEST OVER THE WEST AND ESPECIALLY THE KEWEENAW
PENINSULA WHICH WILL BE JUST TO THE WEST/NORTHWEST OF THE 850/700MB
LOW TRACK. WITH THE INITIAL SURGE OF PRECIPITATION ASSOCIATED WITH
THIS LOW...HAVE RAINFALL AMOUNTS OVER AN 1.25 INCH ACROSS THE ENTIRE
AREA THROUGH WEDNESDAY NIGHT AND THE HIGHEST AMOUNTS OVER NORTHWEST
UPPER MICHIGAN (AMOUNTS OF 1.5-2IN). IN ADDITION TO THE RAIN...WINDS
WILL BE ON THE INCREASE FROM WEST TO EAST WEDNESDAY AFTERNOON INTO
WEDNESDAY NIGHT WITH SOLID NORTHERLY GALES OVER LAKE SUPERIOR.
EXPECT THE STRONG WINDS TO AFFECT THE SHORELINE AREAS WEDNESDAY
NIGHT (GUSTS TO 35KTS) BEFORE GRADUALLY DECREASING THURSDAY THROUGH
FRIDAY. HAVE WINDS RIGHT AROUND WIND ADVISORY CRITERIA OVER
NORTHERN PORTIONS OF THE KEWEENAW PENINSULA AND EVEN IF THEY DON/T
REACH CRITERIA...THERE COULD BE DECENT IMPACTS WITH A SATURATED
GROUND AND LEAVES ON THE TREES HELPING TO CAUSE SOME TREES TO FALL
DOWN.
THE NORTHWEST FLOW BEHIND THE LOW WILL USHER IN COLD AIR ALOFT (850
TEMPS OF -1C BY 18Z THURSDAY) AND LEAD TO LAKE EFFECT RAIN UNDER
NORTHWEST FLOW UNTIL THE SECOND WAVE AND TROUGH AXIS MOVES THROUGH
THURSDAY NIGHT INTO FRIDAY. THIS WILL BRING ANOTHER AREA OF
WIDESPREAD LIGHT RAIN SHOWERS TO THE AREA. BEHIND THAT SECOND
WAVE...EXPECT DRYING CONDITIONS AS AN UPPER/SURFACE RIDGE MOVE INTO
THE AREA THROUGH SUNDAY MORNING. DEPENDING ON HOW QUICKLY SKIES
CLEAR ON FRIDAY NIGHT...COULD SEE LOWS NEARING FREEZING. THINK
BEST CHANCE WOULD BE OVER THE INTERIOR WEST AS IS TRADITIONALLY
THE CASE WITH BACKING LOW LEVEL WINDS. THURSDAY THROUGH SATURDAY
WILL BE A COOL STRETCH AND EXPECT HIGHS TO BE IN THE 50S EACH DAY.
OVER THE WEST ON THURSDAY/FRIDAY...COULD SEE SOME LOCATIONS
STRUGGLING TO RISE OUT OF THE UPPER 40S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 123 AM EDT MON SEP 8 2014
EXPECT VFR CONDITIONS THIS FCST PERIOD. DAYTIME HEATING/MIXING WL
ALLOW FOR GUSTY WINDS TO 15-20 KT MON AFTN AND WINDS WILL STAY UP
THROUGH MON EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 AM EDT MON SEP 8 2014
FOG MAY CONTINUE TO BE A CONCERN INITIALLY OVER PORTIONS OF W AND
CENTRAL LAKE SUPERIOR. LAKE SUPERIOR WILL INITIALLY BE STUCK BETWEEN
EXITING HIGH PRESSURE OVER THE NEW ENGLAND STATES...AND A NEARING
TROUGH STRETCHING FROM NORTH DAKOTA THROUGH NORTHERN ONTARIO. LOOK
FOR THE TROUGH TO PUSH INTO LAKE SUPERIOR ON TUESDAY...WHILE A
STRONGER LOW ORGANIZES ACROSS THE CENTRAL PLAINS. EXPECT THE
DEEPENING LOW TO SHIFT NE ACROSS WI ON WEDNESDAY...AND ACROSS E
UPPER MI AND N LOWER MI LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING...BEFORE CONTINUING NE INTO QUEBEC ON THURSDAY. A PERIOD OF
N GALES WILL BE POSSIBLE LATE TUESDAY NIGHT INTO EARLY THURSDAY. IN
LARGE HIGH PRESSURE OVER S ALBERTA AND SASKATCHEWAN THURSDAY IS
EXPECTED TO DIVE ACROSS THE N AND CENTRAL PLAINS...WHILE BUILDING A
RIDGE ACROSS LAKE SUPERIOR ON THURSDAY NIGHT AND FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...07
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
125 AM EDT MON SEP 8 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 358 PM EDT SUN SEP 7 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR LAKES BTWN A BROAD UPR RDG OVER WRN NAMERICA AND A TROF OVER
THE NE STATES. SHRTWV EMBEDDED IN THIS WNW FLOW WHICH WAS RESPONSIBLE
FOR CLOUD COVER AND ISOLD SHRA OVER ERN LAKE SUPERIOR HAS NOW MOVED
EAST OF LAKE SUPERIOR WITH CLOUD COVER GENERALLY ERODING. ANOTHER
SHORTWAVE MOVING EAST THROUGH SOUTH DAKOTA HAS GENERATED SOME WAA
CLOUDS OVER ERN SD BUT NO PCPN AT THIS TIME AS AIR MASS VERY DRY AS
NOTED ON 12Z ABR SNDG.
MAIN FCST CONCERNS WILL FOCUS MAINLY ON TEMPS AND CLOUDS AS AIRMASS
LOOKS TO BE TOO DRY FOR PCPN OVER THE NEXT 24 HRS.
TNGT...TIGHTENING PRES GRADIENT BTWN HI PRES RETREATING TOWARD NEW
ENGLAND AND LO PRES TAKING SHAPE SW OF LK WINNIPEG WILL ALLOW FOR AN
INCREASE IN SSW WIND ACROSS THE AREA TONIGHT. ALTHOUGH THE AIRMASS
WL BE DRY AND SKIES MOSTLY CLR WITH PWATS AROUND 0.75 INCH...THE
STEADY WIND WL TEND TO LIMIT THE DIURNAL TEMP DROP...ESPECIALLY IN
THE DOWNSLOPE AREAS NEAR LK SUP OVER NW UPR MI. EXPECT THE LOWEST
MIN TEMPS (MID TO UPPER 40S) OVER THE INTERIOR ALONG THE WI BDR AND
E WHERE THE PRES GRADIENT WL BE A BIT WEAKER/WINDS LIGHTER.
CONVERSELY MIN TEMPS FOR DOWNSLOPING AREAS ALONG LAKE SUPERIOR WILL
STAY UP IN THE MID TO UPPER 50S.
WAA WILL CONTINUE ON MONDAY WITH INCREASING S WINDS AS UPPER MI
REMAINS STUCK BETWEEN A LARGE AREA OF HIGH PRESSURE EXITING THE NEW
ENGLAND STATES...AND AN ELONGATED LOW PRES TROUGH SET UP FROM THE
CENTRAL PLAINS THROUGH ONTARIO AND HUDSON BAY. 850MB TEMPS WILL
AVERAGE 11-12C BY THE END OF THE DAY SHOULD YIELD HIGH TEMPS IN THE
MID TO UPPER 70S ACROSS THE AREA DESPITE SOME INCREASE IN WAA CLOUDS
AHEAD OF APPROACHING PLAINS SHORTWAVE. SOUTH GUSTS NEAR 20KTS WILL BE
COMMON IN THE AFTERNOON. GIVEN DRY AIRMASS IN PLACE HAVE ELECTED TO
KEEP FCST DRY FOR NOW DESPITE SOME WEAK FORCING AHEAD OF PLAINS
SHORTWAVE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 PM EDT SUN SEP 7 2014
MONDAY NIGHT INTO TUESDAY WILL BE THE TRANSITION PERIOD FROM THE
DRY AND RELATIVELY WARM HIGH PRESSURE DEPARTING THE AREA TO THE
MUCH COOLER AND WET PERIOD IN STORE FOR THE SECOND HALF OF THE WORK
WEEK. THE START OF THIS TRANSITION WILL BE A COLD FRONT EXTENDING
SOUTHWEST FROM A LOW NEAR HUDSON BAY. THIS FRONT WILL SLOWLY SHIFT
TO THE EAST OUT OF MINNESOTA ON MONDAY NIGHT AND INTO WESTERN LAKE
SUPERIOR AND THE WESTERN U.P. TUESDAY. EXPECT ISOLATED/SCATTERED
SHOWERS TO OCCUR ALONG THIS FRONT AS IT SLOWLY MOVES EAST ACROSS THE
U.P. LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT. DID CONTINUE TO
INCLUDE A SLIGHT CHANCE OF THUNDER ON THE EAST SIDE OF THE
FRONT/TROUGH DUE TO THE INSTABILITY INCREASING UNDER THE SOUTHERLY
FLOW DURING THE AFTERNOON BEFORE DIMINISHING IN THE EVENING.
THIS SLOW MOVING TROUGH WILL BE THE FOCUS FOR THE TRACK OF THE
STRONG LOW PRESSURE SYSTEM THAT WILL BE DEVELOPING IN THE CENTRAL
PLAINS ON TUESDAY AND THEN QUICKLY LIFTING NORTHEAST THROUGH THE
UPPER GREAT LAKES REGION WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT.
STILL SOME DIFFERENCES IN THE LOW TRACK BETWEEN THE OPERATIONAL
MEMBERS AND ITS LOCATION AT 00Z THURSDAY...BUT THE 00Z ECMWF OR 12Z
GEM RUNS SEEM TO BE A GOOD COMPROMISE WITH THE OTHER MODELS AND
ENSEMBLE MEMBERS. THIS CONSENSUS TRACKS A LOW-MID 990MB LOW FROM
SOUTHEAST MINNESOTA AT 12Z WEDNESDAY TO NORTHERN LAKE MICHIGAN BY
00Z THURSDAY AND INTO QUEBEC ON THURSDAY. 06Z GFS AND 00Z ECMWF
ENSEMBLE MEMBERS SUPPORT THAT IDEA AND AWAY FROM THE FASTER AND
FARTHER EAST SOLUTION SEEN ON THE 12Z GFS. WITH THAT IDEA IN
MIND...EXPECT A TRANSITION FROM THE LIGHTER PRECIP ASSOCIATED WITH
THE SURFACE TROUGH OVER WESTERN/CENTRAL U.P. ON TUESDAY NIGHT TO
WIDESPREAD RAIN LIFTING NORTHEAST ACROSS THE AREA ON WEDNESDAY.
WILL CONTINUE TO SHOW INCREASING POPS DURING THAT PERIOD AS THE
ISENTROPIC ASCENT PUSHES THROUGH THE AREA AND DECIDED UP THE
WEDNESDAY POPS TO DEFINITE VALUES ACROSS THE CWA. DID ADD A SMALL
POCKET OF THUNDER ALONG THE LAKE MICHIGAN BORDER WEDNESDAY WHERE THE
SURFACE LOW WILL TRACK AND POCKET OF ELEVATED INSTABILITY WOULD BE
LOCATED. AS THE LOW LIFTS NORTHEAST ON WEDNESDAY NIGHT...EXPECT THE
RAIN TO LINGER THE LONGEST OVER THE WEST AND ESPECIALLY THE KEWEENAW
PENINSULA WHICH WILL BE JUST TO THE WEST/NORTHWEST OF THE 850/700MB
LOW TRACK. WITH THE INITIAL SURGE OF PRECIPITATION ASSOCIATED WITH
THIS LOW...HAVE RAINFALL AMOUNTS OVER AN 1.25 INCH ACROSS THE ENTIRE
AREA THROUGH WEDNESDAY NIGHT AND THE HIGHEST AMOUNTS OVER NORTHWEST
UPPER MICHIGAN (AMOUNTS OF 1.5-2IN). IN ADDITION TO THE RAIN...WINDS
WILL BE ON THE INCREASE FROM WEST TO EAST WEDNESDAY AFTERNOON INTO
WEDNESDAY NIGHT WITH SOLID NORTHERLY GALES OVER LAKE SUPERIOR.
EXPECT THE STRONG WINDS TO AFFECT THE SHORELINE AREAS WEDNESDAY
NIGHT (GUSTS TO 35KTS) BEFORE GRADUALLY DECREASING THURSDAY THROUGH
FRIDAY. HAVE WINDS RIGHT AROUND WIND ADVISORY CRITERIA OVER
NORTHERN PORTIONS OF THE KEWEENAW PENINSULA AND EVEN IF THEY DON/T
REACH CRITERIA...THERE COULD BE DECENT IMPACTS WITH A SATURATED
GROUND AND LEAVES ON THE TREES HELPING TO CAUSE SOME TREES TO FALL
DOWN.
THE NORTHWEST FLOW BEHIND THE LOW WILL USHER IN COLD AIR ALOFT (850
TEMPS OF -1C BY 18Z THURSDAY) AND LEAD TO LAKE EFFECT RAIN UNDER
NORTHWEST FLOW UNTIL THE SECOND WAVE AND TROUGH AXIS MOVES THROUGH
THURSDAY NIGHT INTO FRIDAY. THIS WILL BRING ANOTHER AREA OF
WIDESPREAD LIGHT RAIN SHOWERS TO THE AREA. BEHIND THAT SECOND
WAVE...EXPECT DRYING CONDITIONS AS AN UPPER/SURFACE RIDGE MOVE INTO
THE AREA THROUGH SUNDAY MORNING. DEPENDING ON HOW QUICKLY SKIES
CLEAR ON FRIDAY NIGHT...COULD SEE LOWS NEARING FREEZING. THINK
BEST CHANCE WOULD BE OVER THE INTERIOR WEST AS IS TRADITIONALLY
THE CASE WITH BACKING LOW LEVEL WINDS. THURSDAY THROUGH SATURDAY
WILL BE A COOL STRETCH AND EXPECT HIGHS TO BE IN THE 50S EACH DAY.
OVER THE WEST ON THURSDAY/FRIDAY...COULD SEE SOME LOCATIONS
STRUGGLING TO RISE OUT OF THE UPPER 40S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 123 AM EDT MON SEP 8 2014
EXPECT VFR CONDITIONS THIS FCST PERIOD. DAYTIME HEATING/MIXING WL
ALLOW FOR GUSTY WINDS TO 15-20 KT MON AFTN AND WINDS WILL STAY UP
THROUGH MON EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 358 PM EDT SUN SEP 7 2014
LARGE HIGH PRESSURE STRETCHING FROM THE CENTRAL PLAINS THROUGH THE
LOWER GREAT LAKES WILL EXIT TO THE NEW ENGLAND STATES TONIGHT.
MEANWHILE...A LOW PRES TROUGH WILL DEVELOP FROM HUDSON BAY THROUGH
WRN ONTARIO INTO THE NRN PLAINS. LOW PRES DEVELOPING OVER THE
CENTRAL PLAINS BY TUE WILL MOVE NE ACROSS THE UPPER GREAT LAKES LATE
WEDNESDAY AND WEDNESDAY NIGHT...BEFORE EXITING INTO QUEBEC ON
THURSDAY. A PERIOD OF N GALES WILL BE POSSIBLE LATE TUE
NIGHT INTO EARLY THURSDAY. INCLUDED AREAS OF FOG OVER NCNTRL LAKE
SUPERIOR WHERE PATCH OF FOG HAS RESIDED MUCH OF THE AFTERNOON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...07
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
304 AM CDT MON SEP 8 2014
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 255 AM CDT MON SEP 8 2014
HOW FAR SOUTH INTO THE FA WILL MORNING CONVECTION MAKE IT AND
THEN HOW QUICKLY WILL CONVECTION DEVELOP ON TUESDAY MAIN FORECAST
FOCUS IN THE SHORT TERM...ALTHOUGH SEVERE WEATHER AND HEAVY RAIN
REMAIN IN THE PICTURE FOR LATE TUESDAY.
A MERGING THUNDERSTORM CLUSTER WAS WORKING TOWARD NERN NEBR AS OF
8Z BUT ALSO MOVING INTO MLCAPE VALUE AREAS THAT WERE LESS THAN
500 J/KG PER SPC MESO PAGE. THUS WOULD SUSPECT SOME WEAKENING ON
SE EDGE THIS MORNING WHICH WAS HINTED AT BY 05Z HRRR AND RAP WHICH
KEPT MOST OF THE PRECIP IN FAR NE ZONES OR EVEN NE OF THERE...AS
DID 00Z ECMWF. HOWEVER...THAT SAID CONVECTION WAS MAINTAINING ITS
STRENGTH ENOUGH TO DISCOUNT SHORT TERM MODELS TO SOME DEGREE AND
TO INCREASE POPS IN NERN ZONES THIS MORNING AND KEEP MENTION OF
THEM PER PREV FORECAST IN THE AFTN ALONG E OF MO RIVER. DON/T KNOW
IF IT WILL HOLD TOGETHER AND ROLL DOWN MO RIVER TO OMAHA...BUT
CAN/T RULE THAT OUT ATTM. ALSO SOME HINT BY NAM AND 4KM WRF THAT
SOME NEW DEVELOPMENT COULD OCCUR ON SW SIDE THIS MORNING AND THUS
LEFT IN SMALL POPS FARTHER SW THAN RAP/HRRR WOULD SUGGEST. STILL
COUNTING ON DEBRIS BEING MINIMAL ENOUGH THIS AFTN TO ALLOW MAX
TEMPS TO REACH 80 OR BETTER ALL BUT PERHAPS FAR NERN ZONES.
ALTHOUGH SOME SMALL POPS WERE MAINTAINED TONIGHT...STILL APPEARED
THAT MAIN CONVECTIVE AREAS WOULD EITHER BE TO OUR EAST ON NOSE OF
H85 THETAE RIDGE/JET OR TO OUR WEST AS UPPER TROUGH AND MID LEVEL
MOISTURE APPROACH. THIS MOISTURE...WITH H7 DWPTS FORECAST AT 8-10
DEG C PER NAM/GFS...COULD ALLOW CONVECTION TO START OR INCREASE
FAIRLY EARLY TUESDAY AFTN AND LEAD TO LOCALLY HEAVY RAIN BY
EVENING AS PWATS WILL BE HIGH AND TRAINING OF CELLS PROBABLE.
HOWEVER...A LOT COULD/WILL DEPEND ON INITIAL DEVELOPMENT AND
RESULTANT OUTFLOW OR DIFFERENTIAL HEATING AREAS AND WILL REFRAIN
FROM BLANKET HEAVY RAIN MENTION JUST YET. WITH GENERAL MODEL
CONSENSUS THAT SRN ZONES WOULD BE LAST TO GET WIDESPREAD
CONVECTIVE OVERTURNING...MAX TEMPS IN MID/UPPER 80S ARE POSSIBLE
THERE. ALTHOUGH TEMPS SHOULD BE COOLER FARTHER NORTH...REFRAINED
FROM LOWERING JUST YET AS MORE OF THE WIDESPREAD CONVECTION MAY
HOLD OFF TILL AFTN. POTENTIAL FOR SVR WEATHER ALSO CONTINUES
ESPECIALLY WITH NAM FORECAST HODOGRAPHS FAVORABLY CURVED AHEAD OF
PREFRONTAL TROUGH/COLD FRONT FM OMAHA SWD. LIKE WHERE HEAVIER RAIN
EVENTUALLY SETS UP...SEVERE WEATHER...MAINLY ANY TORNADO
POTENTIAL...TOO WILL BE INFLUENCED BY EARLIER DAY CONVECTION BUT
MENTION OF BOTH SVR+HEAVY RAIN WILL CONTINUE IN THE HWO.
STRONGER CONVECTION COULD LINGER WELL INTO TUESDAY EVENING AND
EVEN EARLY OVERNIGHT HOURS AS LOW LEVEL JET DOESN/T SHIFT SE OF
THE AREA TIL AFTER 06Z PER MODELS...ALTHOUGH STRONGEST AND HEAVY
RAIN THREAT BY MID EVENING SHOULD SHIFT MOSTLY TO SRN AND ERN
ZONES.
ALTHOUGH H85 COOLING WILL LAG DUE TO UPPER FLOW...LOWER LEVEL
COOL/DRY ADVECTION WAS FAIRLY DECENT AND WITH PLENTY OF LOW
CLOUDS LIKELY ON WEDNESDAY...ANY HEATING/RECOVERY WILL BE LIMITED.
GENERALLY TRIMMED BACK BOTH LOWS AND HIGHS. ALTHOUGH A GENERAL
TROUGHING CONTINUED ALOFT...FORCING WAS WEAK PER QG FORECAST FM
GFS AND NAM BY AFTN. SO ALTHOUGH SMALL POPS WERE LEFT IN FOR THE
MORNING WITH A DRY AFTN...MUCH OF ANY PRECIP SHOULD BE PRETTY
LIGHT OR POSSIBLY JUST DRIZZLE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 255 AM CDT MON SEP 8 2014
EXTENDED BEGINS QUITE COOL AS H85 TEMPS LOWER INTO LOW SINGLE
DIGITS THU AND EVEN DROP BELOW ZERO THU NIGHT AS REINFORCING UPPER
SHORTWAVE SENDS EVEN COLDER AIR ACROSS THE FA. THIS WAVE COULD
ALSO SPREAD LIGHT SHOWERS ACROSS THE AREA THU MAKING IT EVEN LESS
LIKELY TO MIX TO H85. THIS IN TURN COULD BRING EVEN COLDER MAX
TEMPS TO THE REGION THAN THIS FORECAST WILL CONTAIN...WHICH WERE
ALREADY NEAR OR BELOW COLDEST MAX TEMPS ON RECORD FOR SEPT 11 OF
58 IN LINCOLN...56 IN OMAHA AND 55 AT NORFOLK.
IF SKIES CLEAR QUICKLY ENOUGH THURSDAY LOWS COULD BE A CATEGORY
COOLER THAN THE GENERALLY 40-45 GOING BY FRIDAY MORNING AND WITH
SURFACE STILL IN VICINITY SAT MORNING MORE 30S COULD BE NEEDED IN
FUTURE FORECASTS THAT DAY AS WELL. OTHERWISE 00Z ECMWF INDICATED
TEMPERATURES SHOULD MODERATE NEXT WEEKEND ALONG WITH PRECIP
HOLDING OFF TILL NEXT WAVE SUN NIGHT. GFS WAS A LITTLE COOLER AND
SUGGESTIVE OF LIGHT PRECIP SAT AS UPPER TROUGH TO BEGIN WEEKEND
WAS A TOUCH MORE AMPLIFIED. FORECAST FOR NEXT SATURDAY AND SUNDAY
WAS KEPT DRY FOR NOW.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1145 PM CDT SUN SEP 7 2014
VFR CONDS ARE STILL EXPECTED THROUGH THE PERIOD. THERE REMAINS AN
ISO CHC OF A SHRA/TSRA LATE TONIGHT AND INTO MON MRNG AT MAINLY
KOFK/KOMA BUT THREAT IS TO LOW TO INCLUDE IN THE TAFS ATTM.
OTHERWISE SOUTH WINDS ARE STILL EXPECTED TO INCREASE ON MON WITH
GUSTS AT ALL 3 SITES. WINDS WILL DIMINISH BY MON EVENING.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...CHERMOK
LONG TERM...CHERMOK
AVIATION...BOUSTEAD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
604 AM EDT MON SEP 8 2014
.SYNOPSIS...
WET WEATHER IS EXPECTED TODAY AS LOW PRESSURE DRAGS TROPICAL
MOISTURE UP ALONG A FRONT THAT HAS STALLED OVER THE EASTERN
CAROLINAS. DRIER AIR BUILDING IN TUESDAY WILL ALLOW FOR A WARMING
TREND WEDNESDAY AND THURSDAY. A FAIRLY ROBUST COLD FRONT MAY ARRIVE
FRIDAY NIGHT OR SATURDAY. THE COLD FRONT WILL MOVE OFF THE COAST
SATURDAY NIGHT WITH HIGH PRESSURE BUILDING IN FROM THE NORTH FOR
SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 600 AM MONDAY...MAIN CONCERN AGAIN IS THE POTENTIAL FOR
EXCESSIVE RAINFALL THROUGH TONIGHT. WEAK LOW PRESSURE WILL SLOWLY
MOVE UP ALONG A STALLED FRONT ACROSS THE EASTERN CAROLINAS.
ALTHOUGH TIMING DIFFERENCES REMAIN...LOW PRESSURE SHOULD BE MOVING
NORTH OF THE FORECAST AREA TUE MORNING. A FRONT LIES FROM ABOUT
ILM TO HYW TO CKI THIS MORNING AND IS EXPECTED TO MOVE LITTLE AND
MAY EVEN RETROGRADE SLIGHTLY AS WEAK LOW PRESSURE MOVES UP ALONG
THE BOUNDARY. PRECIPITABLE WATER VALUES REMAIN NEAR THE 99TH
PERCENTILE AND UP TO 2.4 INCHES. TROPICAL MOISTURE WILL CONTINUE
TO STREAM NORTHWARD ALONG AND AHEAD OF THE FRONT AND WILL BE
LIFTED UP AND OVER THE FRONT WITH GOOD OVERRUNNING BACK ACROSS
EVEN OUR MOST INLAND COUNTIES. THUS...WE ARE EXPECTING AVERAGE
RAINFALL AMOUNTS ACROSS THE FORECAST AREA OF 1 TO 3 INCHES.
HOWEVER...THE POTENTIAL IS THERE FOR TWICE THESE VALUES WHERE
CONVECTION REPEATEDLY MOVES ACROSS THE SAME GENERAL AREA. FLOOD
GUIDANCE HAS COME DOWN SLIGHTLY SINCE SUNDAY OWING TO THE GOOD
RAINFALL AMOUNTS WHICH FELL ACROSS MOST OF THE AREA. THE HEAVIEST
RAINFALL SHOULD OCCUR TODAY INTO THIS EVE...BUT MAY LINGER FOR
MUCH OF THE NIGHT ALONG THE COAST... ESPECIALLY THE CAPE FEAR
AREA. WILL SHOW POPS DIMINISHING IN THE WAKE OF LOW PRESSURE.
THE FLOOD THREAT WHILE REAL...LOOKS TO STILL BE RATHER LOCALIZED AND
THE CONSENSUS AMONG ALL NEARBY NWS OFFICES AND THE NATIONAL CENTER
IS TO FORGO A FLOOD WATCH AT THIS TIME. HOWEVER...WE DO EXPECT
SEVERAL FLOOD ADVISORIES WILL BE ISSUED THROUGH TONIGHT WITH THE
FLOOD RISK GREATEST IN URBANIZED AREAS WHERE DRAINAGE IS POOR.
THICK CLOUDS AND PRECIPITATION WILL GREATLY REDUCE THE DIURNAL RANGE
AND WE ARE ONLY EXPECTING HIGHS TO REACH THE LOWER 80S WITH SOME OF
OUR NORTHERN MOST COMMUNITIES PERHAPS FALLING JUST SHORT OF 80
DEGREES. TONIGHT...LOWS WILL BE IN THE UPPER 60S TO LOWER
70S...COOLEST ALONG AND WEST OF INTERSTATE 95.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM MONDAY...FRONTAL LOW WILL BE CROSSING THE REGION ON
TUESDAY. THERE IS STILL SOME MINOR TIMING DIFFERENCES BU THE
SLIGHTLY QUICKER WRF SEEMS TO FIT BEST WITH PREVIOUS THINKING. AFTER
WHAT SHOULD STILL BE A RATHER WET START RAIN CHANCES AND MOREOVER
RAINFALL AMOUNTS WILL BE ON THE WANE BY AFTERNOON AS MID LEVEL
DRYING IN ZONAL FLOW INCREASINGLY OFFSETS THE LINGERING LL FRONTAL
MOISTURE. AS THIS DRYING TREND CONTINUES DOWN INTO THE LOWER LEVELS
TUESDAY NIGHT INTO WEDNESDAY TI WILL NOT ONLY LEAD TO A FURTHER
DECREASE IN RAIN CHANCES (TO NEAR ZERO) BUT ALSO TAKE ON THE FORM OF
DECREASING CLOUD COVER. TEMPS TUESDAY WILL HAVE A COASTAL VS INLAND
RANGE AS THE LATTER MAY SEE SOME BREAKS OF SUN THAT ADD A FEW
DEGREES OF WARMTH. ON WEDNESDAY A WEAK SFC GRADIENT PAIRED WITH SOME
SUBTLE HEIGHT RISES ALOFT SHOULD YIELD SEASONABLE TO SLIGHTLY WARM
TEMPERATURES.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...WARM WEATHER EXPECTED THURSDAY AND FRIDAY WITH
A GRADUAL INCREASE IN RAIN CHANCES STARTING THURSDAY NIGHT AS A COLD
FRONT APPROACHES. THE GFS HAS MADE A CONSIDERABLE SHIFT TOWARDS
QUICKER TIMING WITH THIS BOUNDARY THAT COULD IMPLY THAT FRIDAY IS IN
FACT NOT THAT MILD ANYMORE. POSSIBLE...BUT TOO NEW AN IDEA TO LATCH
ONTO AT THIS POINT. INTERESTINGLY THE 00Z ECMWF IS SLOWER THAN NOT
ONLY PREV MODEL BUT PREV THINKING. BEST GUESS IS THAT HIGHEST POPS
SHOULD COME FRIDAY NIGHT. TEMPERATURES WILL ALSO BE HIGHLY MODULATED
BY THE TIMING OF FROPA AS IT MAY BE PACKING SOME CONSIDERABLY COOLER
AIR.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...UNSETTLED WEATHER WILL PERSIST THROUGH THE PERIOD AS
A SURFACE LOW SLOWLY MOVES UP THE COAST AND MERGES WITH A STALLING
COLD FRONT OVER THE EASTERN CAROLINAS. THE LATEST HRRR RUNS DEPICT
SHRA/TSRA INCREASING IN COVERAGE THIS MORNING. THE HEAVIEST
ACTIVITY IS EXPECTED ALONG THE COAST...WHERE DOWNPOURS COULD
BRIEFLY REDUCE VSBYS TO MVFR/IFR LEVELS. POST-FRONTAL IFR CIGS ARE
ALREADY SPREADING OVER OUR INLAND ZONES...SO THE STRATUS AT
KLBT/KFLO WILL LIKELY PERSIST THROUGH THE MORNING HOURS. EXPECT
MAINLY MVFR CIGS AT THE COASTAL TERMS...THOUGH PERSISTENT RAINFALL
COULD LOWER CIGS BELOW 1KFT AT TIMES.
EXPECT MORE WIDESPREAD SHOWERS/ISO TSTMS DURING THE DAY AS THE LOW
MOVES UP THE COAST. MVFR CONDITIONS ARE EXPECTED TO PREVAIL DURING
THE AFTN WITH BRIEF AND LOCALIZED AREAS OF IFR. THERE IS STILL SOME
UNCERTAINTY REGARDING THE SPEED AND TRACK OF THE LOW...WHICH MAKES
FOR A LOWER CONFIDENCE WIND FORECAST. IT LOOKS LIKE THE COAST WILL
SEE SOUTHEAST WINDS 10 KT WITH HIGHER GUSTS POSSIBLE IF THE LOW
DEEPENS. MEANWHILE THE INLAND TERMS WILL KEEP NORTHEAST WINDS AOB 10
KT FOR MUCH OF THE DAY. PCPN WILL TAPER OFF FROM SW TO NE AS THE LOW
CONTINUES MOVING NORTHWARD...WITH WINDS SHIFTING TO THE NORTH ON THE
BACKSIDE OF THE LOW NEAR THE END OF THE PERIOD.
EXTENDED OUTLOOK...CHANCE OF SHOWERS EARLY TUESDAY. OTHERWISE VFR
WILL PREVAIL THROUGH THURSDAY. SHOWERS/TSTMS RETURN ON FRIDAY AS
ANOTHER COLD FRONT APPROACHES OUR CWA.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 600 AM MONDAY...A SMALL CRAFT SHOULD EXERCISE CAUTION HAS
BEEN ISSUED FOR TODAY FOR ALL WATERS EXCEPT THOSE NORTH OF THE
MOUTH OF THE CAPE FEAR RIVER. WE DO EXPECT THAT HIGHER WINDS AND
SEAS WILL SPREAD INTO THE NORTHERNMOST WATERS TONIGHT. MARINERS
SHOULD EXPECT WIDESPREAD HEAVY RAIN AND POOR VISIBILITIES ACROSS
THE WATERS IN TROPICAL DOWNPOURS INTO TONIGHT.
LOW PRESSURE WILL MOVE UP ALONG A STALLED FRONT JUST WEST OF THE
WATERS. THIS WILL TIGHTEN THE PRESSURE GRADIENT...RESULTING IN
BUILDING SEAS AND INCREASING WINDS. WINDS ARE EXPECTED TO PEAK
AROUND 20 KT WITH WIND SPEEDS INCREASING ACROSS THE SOUTHERN WATERS
THIS MORNING AND THE NORTHERN WATERS THIS AFTERNOON AND TONIGHT.
GUSTS TO AROUND 25 KT WILL BE POSSIBLE. THE DIRECTION SHOULD HOLD
SOUTH TODAY...AND THEN VEER AS LOW PRESSURE MOVES NORTH OF OUR
LATITUDE. SW TO W WINDS SHOULD GRADUALLY DEVELOP ACROSS THE WATERS
OVERNIGHT AND TUE MORNING. AS THE DIRECTION VEERS...WIND SPEEDS WILL
DIMINISH.
IN RESPONSE TO THE INCREASING WINDS...SEAS WILL BUILD TO 4 TO 5 FT.
IT IS POSSIBLE FOR A BRIEF PERIOD OF 6 FT SEAS. SEAS WILL BE HIGHEST
ACROSS THE SOUTHERN WATERS TODAY AND THE NORTHERN WATERS TONIGHT.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...THE START OF THE PERIOD WILL BE THE MOST
ACTIVE AS LOW PRESSURE MOVES UP FRONTAL BOUNDARY JUST INLAND FROM
THE COAST. THIS WILL TIGHTEN THE GRADIENT TO THE POINT WHERE WINDS
SHOULD BE IN THE 15 TO 20 KT RANGE MOST AREAS...ALTHOUGH WIND SPEEDS
MAY ALREADY BE FALLING OVER SOUTHERN ZONES. SOME 5 FT SEAS MAY BE
AFFECTING WATERS ALONG FRYING PAN SHOALS BUT ENOUGH OF A
NEARSHORE/OFFSHORE GRADIENT EXPECTED TO PRECLUDE CAUTIONARY
HEADLINES. THE EXIT OF THE WAVE WILL LEAD TO FAIRLY RAPID DECREASE
IN WINDS AND SEAS LATE TUESDAY INTO TUESDAY NIGHT FROM SOUTH TO
NORTH. AS WIND SPEEDS DECREASE THERE WILL ALSO BE VEERING IN
DIRECTION AND THE EXITING WAVE PUSHES THE FRONT OFFSHORE. A LIGHT
NORTHERLY WIND IS THUS EXPECTED ON WEDNESDAY AT LEAST TO START THE
DAY. A TURN TO A MORE ONSHORE DIRECTION WILL AT FIRST BE LOCALIZED
AS THE SEA BREEZE KICKS IN BUT THEN SHOULD OCCUR GENTLY AREA-WIDE AS
THE SYNOPTIC SCALE FLOW TURNS TO WEAKLY SOUTHERLY.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 AM MONDAY...JUST A GENTLE SW FLOW DEVELOPING ON THURSDAY
AS THE NORMAL WEST ATLANTIC HIGH PRESSURE HAS TROUBLE GETTING
ESTABLISHED INTO THE SOUTHEAST AND MID ATLANTIC BY SOME LINGER
TROUGINESS. THIS FLOW REGIME WILL STRENGTHEN ON FRIDAY AS A FAIRLY
STRONG COLD FRONT APPROACHES. MODELS HAVE DIVERGED OVERNIGHT WITH
THE TIMING OF THIS FRONT SO THE DEGREE OF STRENGTHENING HAS COME
INTO QUESTION.
&&
.TIDES/COASTAL FLOODING...
AS OF 600 AM MONDAY...THE LOWER CAPE FEAR RIVER IS EXPECTED TO
EXCEED MINOR COASTAL FLOOD THRESHOLDS DURING HIGH TIDE THIS
MORNING AND A COASTAL FLOOD ADVISORY HAS BEEN ISSUED. THE EVENING
HIGH TIDE WILL BE THE HIGHER OF THE TWO HIGH TIDES AND WE EXPECT
WATER LEVELS WILL BE EVEN HIGHER LATE THIS EVENING. HIGH TIDE IN
DOWNTOWN WILMINGTON IS AT 930 AM AND 10 PM.
THE RISK FOR MINOR COASTAL FLOODING ALONG PORTIONS OF THE LOWER
CAPE FEAR RIVER DURING HIGH TIDE WILL CONTINUE FOR MUCH OF THE
WEEK. THE FULL MOON IS TODAY. THE LATE NIGHT TIDE WILL BE HIGHEST.
THE FULL MOON MAY EXACERBATE ANY FLOOD ISSUES ALONG THE COAST
THIS MORNING AND AGAIN THIS EVE. HIGH TIDE AT THE BEACHES IS
AROUND 7 AM AND 730 PM. HOWEVER...WE DO NOT EXPECT MINOR COASTAL
FLOOD THRESHOLDS TO BE REACHED AT THE BEACHES.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...COASTAL FLOOD ADVISORY UNTIL 11 AM EDT THIS MORNING FOR NCZ107.
MARINE...NONE.
&&
$$
NEAR TERM...RJD
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...RJD/BJR
TIDES/COASTAL FLOODING...RJD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
341 AM EDT MON SEP 8 2014
.SYNOPSIS...
WET WEATHER IS EXPECTED TODAY AS LOW PRESSURE DRAGS TROPICAL
MOISTURE UP ALONG A FRONT THAT HAS STALLED OVER THE EASTERN
CAROLINAS. DRIER AIR BUILDING IN TUESDAY WILL ALLOW FOR A WARMING
TREND WEDNESDAY AND THURSDAY. A FAIRLY ROBUST COLD FRONT MAY ARRIVE
FRIDAY NIGHT OR SATURDAY. THE COLD FRONT WILL MOVE OFF THE COAST
SATURDAY NIGHT WITH HIGH PRESSURE BUILDING IN FROM THE NORTH FOR
SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM MONDAY...MAIN CONCERN AGAIN IS THE POTENTIAL FOR
EXCESSIVE RAINFALL THROUGH TONIGHT. WEAK LOW PRESSURE WILL SLOWLY
MOVE UP ALONG A STALLED FRONT ACROSS THE EASTERN CAROLINAS. ALTHOUGH
TIMING DIFFERENCES REMAIN...LOW PRESSURE SHOULD BE MOVING NORTH OF
THE FORECAST AREA TUE MORNING. A FRONT LIES FROM ABOUT ILM TO HYW TO
CKI THIS MORNING AND IS EXPECTED TO MOVE LITTLE AND MAY EVEN
RETROGRADE SLIGHTLY AS WEAK LOW PRESSURE MOVES UP ALONG THE
BOUNDARY. PRECIPITABLE WATER VALUES REMAIN NEAR THE 99TH PERCENTILE
AND UP TO 2.4 INCHES. TROPICAL MOISTURE WILL CONTINUE TO STREAM
NORTHWARD ALONG AND AHEAD OF THE FRONT AND WILL BE LIFTED UP AND
OVER THE FRONT WITH GOOD OVERRUNNING BACK ACROSS EVEN OUR MOST
INLAND COUNTIES. THUS...WE ARE EXPECTING AVERAGE RAINFALL AMOUNTS
ACROSS THE FORECAST AREA OF 1 TO 3 INCHES. HOWEVER...THE POTENTIAL
IS THERE FOR TWICE THESE VALUES WHERE CONVECTION REPEATEDLY MOVES
ACROSS THE SAME GENERAL AREA. FLOOD GUIDANCE HAS COME DOWN SLIGHTLY
SINCE SUNDAY OWING TO THE GOOD RAINFALL AMOUNTS WHICH FELL ACROSS
MOST OF THE AREA. THE HEAVIEST RAINFALL SHOULD OCCUR TODAY INTO THIS
EVE...BUT MAY LINGER FOR MUCH OF THE NIGHT ALONG THE COAST...
ESPECIALLY THE CAPE FEAR AREA. WILL SHOW POPS DIMINISHING IN THE
WAKE OF LOW PRESSURE.
THE FLOOD THREAT WHILE REAL...LOOKS TO STILL BE RATHER LOCALIZED AND
THE CONSENSUS AMONG ALL NEARBY NWS OFFICES AND THE NATIONAL CENTER
IS TO FORGO A FLOOD WATCH AT THIS TIME. HOWEVER...WE DO EXPECT
SEVERAL FLOOD ADVISORIES WILL BE ISSUED THROUGH TONIGHT WITH THE
FLOOD RISK GREATEST IN URBANIZED AREAS WHERE DRAINAGE IS POOR. THE
FULL MOON MAY EXACERBATE ANY FLOOD ISSUES ALONG THE COAST THIS
MORNING AND AGAIN THIS EVE. HIGH TIDE AT THE BEACHES IS AROUND 7
AM AND 730 PM. HOWEVER...WE DO NOT EXPECT MINOR COASTAL FLOOD
THRESHOLDS TO BE REACHED AT THE BEACHES. HOWEVER...THE LOWER CAPE
FEAR RIVER WILL BE MORE PROBLEMATIC. ALTHOUGH WE SHOULD STAY JUST
BELOW CRITERIA THIS MORNING...WE WILL LIKELY AGAIN EXCEED THRESHOLDS
THIS EVE. HIGH TIDE IN DOWNTOWN WILMINGTON IS AT 930 AM AND 10 PM.
THICK CLOUDS AND PRECIPITATION WILL GREATLY REDUCE THE DIURNAL RANGE
AND WE ARE ONLY EXPECTING HIGHS TO REACH THE LOWER 80S WITH SOME OF
OUR NORTHERN MOST COMMUNITIES PERHAPS FALLING JUST SHORT OF 80
DEGREES. TONIGHT...LOWS WILL BE IN THE UPPER 60S TO LOWER
70S...COOLEST ALONG AND WEST OF INTERSTATE 95.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...FRONTAL LOW WILL BE CROSSING THE REGION ON
TUESDAY. THERE IS STILL SOME MINOR TIMING DIFFERENCES BU THE
SLIGHTLY QUICKER WRF SEEMS TO FIT BEST WITH PREVIOUS THINKING. AFTER
WHAT SHOULD STILL BE A RATHER WET START RAIN CHANCES AND MOREOVER
RAINFALL AMOUNTS WILL BE ON THE WANE BY AFTERNOON AS MID LEVEL
DRYING IN ZONAL FLOW INCREASINGLY OFFSETS THE LINGERING LL FRONTAL
MOISTURE. AS THIS DRYING TREND CONTINUES DOWN INTO THE LOWER LEVELS
TUESDAY NIGHT INTO WEDNESDAY TI WILL NOT ONLY LEAD TO A FURTHER
DECREASE IN RAIN CHANCES (TO NEAR ZERO) BUT ALSO TAKE ON THE FORM OF
DECREASING CLOUD COVER. TEMPS TUESDAY WILL HAVE A COASTAL VS INLAND
RANGE AS THE LATTER MAY SEE SOME BREAKS OF SUN THAT ADD A FEW
DEGREES OF WARMTH. ON WEDNESDAY A WEAK SFC GRADIENT PAIRED WITH SOME
SUBTLE HEIGHT RISES ALOFT SHOULD YIELD SEASONABLE TO SLIGHTLY WARM
TEMPERATURES.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...WARM WEATHER EXPECTED THURSDAY AND FRIDAY WITH
A GRADUAL INCREASE IN RAIN CHANCES STARTING THURSDAY NIGHT AS A COLD
FRONT APPROACHES. THE GFS HAS MADE A CONSIDERABLE SHIFT TOWARDS
QUICKER TIMING WITH THIS BOUNDARY THAT COULD IMPLY THAT FRIDAY IS IN
FACT NOT THAT MILD ANYMORE. POSSIBLE...BUT TOO NEW AN IDEA TO LATCH
ONTO AT THIS POINT. INTERESTINGLY THE 00Z ECMWF IS SLOWER THAN NOT
ONLY PREV MODEL BUT PREV THINKING. BEST GUESS IS THAT HIGHEST POPS
SHOULD COME FRIDAY NIGHT. TEMPERATURES WILL ALSO BE HIGHLY MODULATED
BY THE TIMING OF FROPA AS IT MAY BE PACKING SOME CONSIDERABLY COOLER
AIR.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...UNSETTLED WEATHER WILL PERSIST THROUGH THE PERIOD AS A
SURFACE LOW SLOWLY MOVES UP THE COAST AND MERGES WITH A STALLING
COLD FRONT OVER THE EASTERN CAROLINAS. THE LATEST HRRR RUNS DEPICT
SHRA/TSRA INCREASING IN COVERAGE THIS MORNING. THE HEAVIEST ACTIVITY
IS EXPECTED ALONG THE COAST...WHERE DOWNPOURS COULD BRIEFLY REDUCE
VSBYS TO MVFR/IFR LEVELS. POST-FRONTAL IFR CIGS ARE ALREADY
SPREADING OVER OUR INLAND ZONES...SO THE STRATUS AT KLBT/KFLO WILL
LIKELY PERSIST THROUGH THE MORNING HOURS. EXPECT MAINLY MVFR CIGS AT
THE COASTAL TERMS...THOUGH PERSISTENT RAINFALL COULD LOWER CIGS
BELOW 1KFT AT TIMES.
EXPECT MORE WIDESPREAD SHOWERS/ISO TSTMS DURING THE DAY AS THE LOW
MOVES UP THE COAST. MVFR CONDITIONS ARE EXPECTED TO PREVAIL DURING
THE AFTN WITH BRIEF AND LOCALIZED AREAS OF IFR. THERE IS STILL SOME
UNCERTAINTY REGARDING THE SPEED AND TRACK OF THE LOW...WHICH MAKES
FOR A LOWER CONFIDENCE WIND FORECAST. IT LOOKS LIKE THE COAST WILL
SEE SOUTHEAST WINDS 10 KT WITH HIGHER GUSTS POSSIBLE IF THE LOW
DEEPENS. MEANWHILE THE INLAND TERMS WILL KEEP NORTHEAST WINDS AOB 10
KT FOR MUCH OF THE DAY. PCPN WILL TAPER OFF FROM SW TO NE AS THE LOW
CONTINUES MOVING NORTHWARD...WITH WINDS SHIFTING TO THE NORTH ON THE
BACKSIDE OF THE LOW NEAR THE END OF THE PERIOD.
EXTENDED OUTLOOK...CHANCE OF SHOWERS EARLY TUESDAY. OTHERWISE VFR
WILL PREVAIL THROUGH THURSDAY. SHOWERS/TSTMS RETURN ON FRIDAY AS
ANOTHER COLD FRONT APPROACHES OUR CWA.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM MONDAY...A SMALL CRAFT SHOULD EXERCISE CAUTION HAS BEEN
ISSUED FOR TODAY FOR ALL WATERS EXCEPT THOSE NORTH OF THE MOUTH OF
THE CAPE FEAR RIVER. WE DO EXPECT THAT HIGHER WINDS AND SEAS WILL
SPREAD INTO THE NORTHERNMOST WATERS TONIGHT. MARINERS SHOULD EXPECT
WIDESPREAD HEAVY RAIN AND POOR VISIBILITIES ACROSS THE WATERS IN
TROPICAL DOWNPOURS INTO TONIGHT.
LOW PRESSURE WILL MOVE UP ALONG A STALLED FRONT JUST WEST OF THE
WATERS. THIS WILL TIGHTEN THE PRESSURE GRADIENT...RESULTING IN
BUILDING SEAS AND INCREASING WINDS. WINDS ARE EXPECTED TO PEAK
AROUND 20 KT WITH WIND SPEEDS INCREASING ACROSS THE SOUTHERN WATERS
THIS MORNING AND THE NORTHERN WATERS THIS AFTERNOON AND TONIGHT.
GUSTS TO AROUND 25 KT WILL BE POSSIBLE. THE DIRECTION SHOULD HOLD
SOUTH TODAY...AND THEN VEER AS LOW PRESSURE MOVES NORTH OF OUR
LATITUDE. SW TO W WINDS SHOULD GRADUALLY DEVELOP ACROSS THE WATERS
OVERNIGHT AND TUE MORNING. AS THE DIRECTION VEERS...WIND SPEEDS WILL
DIMINISH.
IN RESPONSE TO THE INCREASING WINDS...SEAS WILL BUILD TO 4 TO 5 FT.
IT IS POSSIBLE FOR A BRIEF PERIOD OF 6 FT SEAS. SEAS WILL BE HIGHEST
ACROSS THE SOUTHERN WATERS TODAY AND THE NORTHERN WATERS TONIGHT.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...THE START OF THE PERIOD WILL BE THE MOST
ACTIVE AS LOW PRESSURE MOVES UP FRONTAL BOUNDARY JUST INLAND FROM
THE COAST. THIS WILL TIGHTEN THE GRADIENT TO THE POINT WHERE WINDS
SHOULD BE IN THE 15 TO 20 KT RANGE MOST AREAS...ALTHOUGH WIND SPEEDS
MAY ALREADY BE FALLING OVER SOUTHERN ZONES. SOME 5 FT SEAS MAY BE
AFFECTING WATERS ALONG FRYING PAN SHOALS BUT ENOUGH OF A
NEARSHORE/OFFSHORE GRADIENT EXPECTED TO PRECLUDE CAUTIONARY
HEADLINES. THE EXIT OF THE WAVE WILL LEAD TO FAIRLY RAPID DECREASE
IN WINDS AND SEAS LATE TUESDAY INTO TUESDAY NIGHT FROM SOUTH TO
NORTH. AS WIND SPEEDS DECREASE THERE WILL ALSO BE VEERING IN
DIRECTION AND THE EXITING WAVE PUSHES THE FRONT OFFSHORE. A LIGHT
NORTHERLY WIND IS THUS EXPECTED ON WEDNESDAY AT LEAST TO START THE
DAY. A TURN TO A MORE ONSHORE DIRECTION WILL AT FIRST BE LOCALIZED
AS THE SEA BREEZE KICKS IN BUT THEN SHOULD OCCUR GENTLY AREA-WIDE AS
THE SYNOPTIC SCALE FLOW TURNS TO WEAKLY SOUTHERLY.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 AM MONDAY...JUST A GENTLE SW FLOW DEVELOPING ON THURSDAY
AS THE NORMAL WEST ATLANTIC HIGH PRESSURE HAS TROUBLE GETTING
ESTABLISHED INTO THE SOUTHEAST AND MID ATLANTIC BY SOME LINGER
TROUGINESS. THIS FLOW REGIME WILL STRENGTHEN ON FRIDAY AS A FAIRLY
STRONG COLD FRONT APPROACHES. MODELS HAVE DIVERGED OVERNIGHT WITH
THE TIMING OF THIS FRONT SO THE DEGREE OF STRENGTHENING HAS COME
INTO QUESTION.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RJD
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...BJR/RJD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
330 AM EDT MON SEP 8 2014
.SYNOPSIS...
WET WEATHER IS EXPECTED TODAY AS LOW PRESSURE DRAGS TROPICAL
MOISTURE UP ALONG A FRONT THAT HAS STALLED OVER THE EASTERN
CAROLINAS. DRIER AIR BUILDING IN TUESDAY WILL ALLOW FOR A WARMING
TREND WEDNESDAY AND THURSDAY. A FAIRLY ROBUST COLD FRONT MAY ARRIVE
FRIDAY NIGHT OR SATURDAY. THE COLD FRONT WILL MOVE OFF THE COAST
SATURDAY NIGHT WITH HIGH PRESSURE BUILDING IN FROM THE NORTH FOR
SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM MONDAY...MAIN CONCERN AGAIN IS THE POTENTIAL FOR
EXCESSIVE RAINFALL THROUGH TONIGHT. WEAK LOW PRESSURE WILL SLOWLY
MOVE UP ALONG A STALLED FRONT ACROSS THE EASTERN CAROLINAS. ALTHOUGH
TIMING DIFFERENCES REMAIN...LOW PRESSURE SHOULD BE MOVING NORTH OF
THE FORECAST AREA TUE MORNING. A FRONT LIES FROM ABOUT ILM TO HYW TO
CKI THIS MORNING AND IS EXPECTED TO MOVE LITTLE AND MAY EVEN
RETROGRADE SLIGHTLY AS WEAK LOW PRESSURE MOVES UP ALONG THE
BOUNDARY. PRECIPITABLE WATER VALUES REMAIN NEAR THE 99TH PERCENTILE
AND UP TO 2.4 INCHES. TROPICAL MOISTURE WILL CONTINUE TO STREAM
NORTHWARD ALONG AND AHEAD OF THE FRONT AND WILL BE LIFTED UP AND
OVER THE FRONT WITH GOOD OVERRUNNING BACK ACROSS EVEN OUR MOST
INLAND COUNTIES. THUS...WE ARE EXPECTING AVERAGE RAINFALL AMOUNTS
ACROSS THE FORECAST AREA OF 1 TO 3 INCHES. HOWEVER...THE POTENTIAL
IS THERE FOR TWICE THESE VALUES WHERE CONVECTION REPEATEDLY MOVES
ACROSS THE SAME GENERAL AREA. FLOOD GUIDANCE HAS COME DOWN SLIGHTLY
SINCE SUNDAY OWING TO THE GOOD RAINFALL AMOUNTS WHICH FELL ACROSS
MOST OF THE AREA. THE HEAVIEST RAINFALL SHOULD OCCUR TODAY INTO THIS
EVE...BUT MAY LINGER FOR MUCH OF THE NIGHT ALONG THE COAST...
ESPECIALLY THE CAPE FEAR AREA. WILL SHOW POPS DIMINISHING IN THE
WAKE OF LOW PRESSURE.
THE FLOOD THREAT WHILE REAL...LOOKS TO STILL BE RATHER LOCALIZED AND
THE CONSENSUS AMONG ALL NEARBY NWS OFFICES AND THE NATIONAL CENTER
IS TO FORGO A FLOOD WATCH AT THIS TIME. HOWEVER...WE DO EXPECT
SEVERAL FLOOD ADVISORIES WILL BE ISSUED THROUGH TONIGHT WITH THE
FLOOD RISK GREATEST IN URBANIZED AREAS WHERE DRAINAGE IS POOR. THE
FULL MOON MAY EXACERBATE ANY FLOOD ISSUES ALONG THE COAST THIS
MORNING AND AGAIN THIS EVE. HIGH TIDE AT THE BEACHES IS AROUND 7
AM AND 730 PM. HOWEVER...WE DO NOT EXPECT MINOR COASTAL FLOOD
THRESHOLDS TO BE REACHED AT THE BEACHES. HOWEVER...THE LOWER CAPE
FEAR RIVER WILL BE MORE PROBLEMATIC. ALTHOUGH WE SHOULD STAY JUST
BELOW CRITERIA THIS MORNING...WE WILL LIKELY AGAIN EXCEED THRESHOLDS
THIS EVE. HIGH TIDE IN DOWNTOWN WILMINGTON IS AT 930 AM AND 10 PM.
THICK CLOUDS AND PRECIPITATION WILL GREATLY REDUCE THE DIURNAL RANGE
AND WE ARE ONLY EXPECTING HIGHS TO REACH THE LOWER 80S WITH SOME OF
OUR NORTHERN MOST COMMUNITIES PERHAPS FALLING JUST SHORT OF 80
DEGREES. TONIGHT...LOWS WILL BE IN THE UPPER 60S TO LOWER
70S...COOLEST ALONG AND WEST OF INTERSTATE 95.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM MONDAY...FRONTAL LOW WILL BE CROSSING THE REGION ON
TUESDAY. THERE IS STILL SOME MINOR TIMING DIFFERENCES BU THE
SLIGHTLY QUICKER WRF SEEMS TO FIT BEST WITH PREVIOUS THINKING. AFTER
WHAT SHOULD STILL BE A RATHER WET START RAIN CHANCES AND MOREOVER
RAINFALL AMOUNTS WILL BE ON THE WANE BY AFTERNOON AS MID LEVEL
DRYING IN ZONAL FLOW INCREASINGLY OFFSETS THE LINGERING LL FRONTAL
MOISTURE. AS THIS DRYING TREND CONTINUES DOWN INTO THE LOWER LEVELS
TUESDAY NIGHT INTO WEDNESDAY TI WILL NOT ONLY LEAD TO A FURTHER
DECREASE IN RAIN CHANCES (TO NEAR ZERO) BUT ALSO TAKE ON THE FORM OF
DECREASING CLOUD COVER. TEMPS TUESDAY WILL HAVE A COASTAL VS INLAND
RANGE AS THE LATTER MAY SEE SOME BREAKS OF SUN THAT ADD A FEW
DEGREES OF WARMTH. ON WEDNESDAY A WEAK SFC GRADIENT PAIRED WITH SOME
SUBTLE HEIGHT RISES ALOFT SHOULD YIELD SEASONABLE TO SLIGHTLY WARM
TEMPERATURES.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...WARM WEATHER EXPECTED THURSDAY AND FRIDAY WITH A
GRADUAL INCREASE IN RAIN CHANCES STARTING THURSDAY NIGHT AS A COLD
FRONT APPROACHES. THE GFS HAS MADE A CONSIDERABLE SHIFT TOWARDS
QUICKER TIMING WITH THIS BOUNDARY THAT COULD IMPLY THAT FRIDAY IS IN
FACT NOT THAT MILD ANYMORE. POSSIBLE...BUT TOO NEW AN IDEA TO LATCH
ONTO AT THIS POINT. INTERESTINGLY THE 00Z ECMWF IS SLOWER THAN NOT
ONLY PREV MODEL BUT PREV THINKING. BEST GUESS IS THAT HIGHEST POPS
SHOULD COME FRIDAY NIGHT. TEMPERATURES WILL ALSO BE HIGHLY MODULATED
BY THE TIMING OF FROPA AS IT MAY BE PACKING SOME CONSIDERABLY COOLER
AIR.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...UNSETTLED WEATHER WILL PERSIST THROUGH THE PERIOD AS A
SURFACE LOW SLOWLY MOVES UP THE COAST AND MERGES WITH A STALLING
COLD FRONT OVER THE EASTERN CAROLINAS. THE LATEST HRRR RUNS DEPICT
SHRA/TSRA INCREASING IN COVERAGE THIS MORNING. THE HEAVIEST ACTIVITY
IS EXPECTED ALONG THE COAST...WHERE DOWNPOURS COULD BRIEFLY REDUCE
VSBYS TO MVFR/IFR LEVELS. POST-FRONTAL IFR CIGS ARE ALREADY
SPREADING OVER OUR INLAND ZONES...SO THE STRATUS AT KLBT/KFLO WILL
LIKELY PERSIST THROUGH THE MORNING HOURS. EXPECT MAINLY MVFR CIGS AT
THE COASTAL TERMS...THOUGH PERSISTENT RAINFALL COULD LOWER CIGS
BELOW 1KFT AT TIMES.
EXPECT MORE WIDESPREAD SHOWERS/ISO TSTMS DURING THE DAY AS THE LOW
MOVES UP THE COAST. MVFR CONDITIONS ARE EXPECTED TO PREVAIL DURING
THE AFTN WITH BRIEF AND LOCALIZED AREAS OF IFR. THERE IS STILL SOME
UNCERTAINTY REGARDING THE SPEED AND TRACK OF THE LOW...WHICH MAKES
FOR A LOWER CONFIDENCE WIND FORECAST. IT LOOKS LIKE THE COAST WILL
SEE SOUTHEAST WINDS 10 KT WITH HIGHER GUSTS POSSIBLE IF THE LOW
DEEPENS. MEANWHILE THE INLAND TERMS WILL KEEP NORTHEAST WINDS AOB 10
KT FOR MUCH OF THE DAY. PCPN WILL TAPER OFF FROM SW TO NE AS THE LOW
CONTINUES MOVING NORTHWARD...WITH WINDS SHIFTING TO THE NORTH ON THE
BACKSIDE OF THE LOW NEAR THE END OF THE PERIOD.
EXTENDED OUTLOOK...CHANCE OF SHOWERS EARLY TUESDAY. OTHERWISE VFR
WILL PREVAIL THROUGH THURSDAY. SHOWERS/TSTMS RETURN ON FRIDAY AS
ANOTHER COLD FRONT APPROACHES OUR CWA.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 PM SUNDAY...UPDATED WINDS DUE TO THE POSITIONING OF THE
FRONTAL BOUNDARY JUST INLAND FROM THE COAST. LATEST OBS AND HRRR
TRENDS INDICATE ESE-SSE DIRECTIONS ACROSS THE ILM WATERS DUE TO
THE MEANDERING OF THIS FRONT. PORTIONS OF IT MAY COME WITHIN 15
MILES OR LESS FROM THE IMMEDIATE COAST AT TIMES BUT MODELS REMAIN
ADAMANT IN KEEPING IT INLAND. SIGNIFICANT SEAS REMAIN 2 TO 4 FT
WITH WIND WAVES DOMINATING THE SEAS SPECTRUM...IE. DOMINANT
PERIODS AROUND 5 SECONDS.
SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM MONDAY...THE START OF THE PERIOD WILL BE THE MOST ACTIVE
AS LOW PRESSURE MOVES UP FRONTAL BOUNDARY JUST INLAND FROM THE
COAST. THIS WILL TIGHTEN THE GRADIENT TO THE POINT WHERE WINDS
SHOULD BE IN THE 15 TO 20 KT RANGE MOST AREAS...ALTHOUGH WIND SPEEDS
MAY ALREADY BE FALLING OVER SOUTHERN ZONES. SOME 5 FT SEAS MAY BE
AFFECTING WATERS ALONG FRYING PAN SHOALS BUT ENOUGH OF A
NEARSHORE/OFFSHORE GRADIENT EXPECTED TO PRECLUDE CAUTIONARY
HEADLINES. THE EXIT OF THE WAVE WILL LEAD TO FAIRLY RAPID DECREASE
IN WINDS AND SEAS LATE TUESDAY INTO TUESDAY NIGHT FROM SOUTH TO
NORTH. AS WIND SPEEDS DECREASE THERE WILL ALSO BE VEERING IN
DIRECTION AND THE EXITING WAVE PUSHES THE FRONT OFFSHORE. A LIGHT
NORTHERLY WIND IS THUS EXPECTED ON WEDNESDAY AT LEAST TO START THE
DAY. A TURN TO A MORE ONSHORE DIRECTION WILL AT FIRST BE LOCALIZED
AS THE SEA BREEZE KICKS IN BUT THEN SHOULD OCCUR GENTLY AREA-WIDE AS
THE SYNOPTIC SCALE FLOW TURNS TO WEAKLY SOUTHERLY.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...JUST A GENTLE SW FLOW DEVELOPING ON THURSDAY AS
THE NORMAL WEST ATLANTIC HIGH PRESSURE HAS TROUBLE GETTING
ESTABLISHED INTO THE SOUTHEAST AND MID ATLANTIC BY SOME LINGER
TROUGINESS. THIS FLOW REGIME WILL STRENGTHEN ON FRIDAY AS A FAIRLY
STRONG COLD FRONT APPROACHES. MODELS HAVE DIVERGED OVERNIGHT WITH
THE TIMING OF THIS FRONT SO THE DEGREE OF STRENGTHENING HAS COME
INTO QUESTION.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH/TRA
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...BJR/RJD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
138 AM EDT MON SEP 8 2014
.SYNOPSIS...
WET WEATHER IS EXPECTED THROUGH MONDAY AS LOW PRESSURE DRAGS
TROPICAL MOISTURE UP ALONG A FRONT THAT HAS STALLED OVER THE EASTERN
CAROLINAS. DRIER AIR BUILDING IN TUESDAY WILL ALLOW FOR A WARMING
TREND WEDNESDAY AND THURSDAY. A FAIRLY ROBUST COLD FRONT MAY ARRIVE
FRIDAY NIGHT OR SATURDAY. THE COLD FRONT WILL MOVE OFF THE COAST
SATURDAY NIGHT WITH HIGH PRESSURE BUILDING IN FROM THE NORTH FOR
SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 1100 PM SUNDAY...COASTAL FLOOD ADVISORY FOR ALONG THE CAPE
FEAR RIVER FROM WILMINGTON TO FORT FISHER HAS EXPIRED. THE GAGE
READING PEAKED AT 5.84 FT MLLW AT THIS EVENINGS HIGH TIDE AROUND
945 PM. THE READING 5.5 FT MLLW IS THE THRESHOLD USED FOR MINOR
COASTAL FLOODING TO COMMENCE.
THE COLD FRONT HAS BASICALLY STALLED AND IS ORIENTED NE-SW ACROSS
THE EASTERN CAROLINAS...ROUGHLY 15 TO 40 MILES INLAND FROM THE
IMMEDIATE COAST. THIS BOUNDARY WILL WILL PROVIDE A SOURCE OF LIFT
FOR CONVECTION OVERNIGHT. THE SFC LOW AND ASSOCIATED DYNAMICS
OVER COASTAL GA-SC IS MAKING SOME PROGRESS NE-WARD AND SHOULD
FURTHER INCREASE ITS FORWARD SPEED BY DAYBREAK MONDAY AS IT
ATTACHES TO THE STALLED BOUNDARY. WITH PWS ABOVE 2 INCHES ACROSS
THE MAJORITY OF THE ILM CWA...WEAK INSTABILITY...FORCING FROM THE
SFC BOUNDARY AND DYNAMICS ALOFT ASSOCIATED WITH THE SFC LOW...AND
FRICTIONAL CONVERGENCE FROM ONSHORE FLOW...POPS WILL REACH
CATEGORICAL FOR MUCH OF THE ILM CWA DURING THE PRE-DAWN MONDAY
HRS. HIGHEST QPF ALONG THE IMMEDIATE COAST...TRAILING LOWER AS ONE
PROGRESSES INLAND. HWO WILL MENTION ISOLATED FLOODING FROM THE
HEAVY RAINFALL...MAINLY FROM THE I-95 CORRIDOR EAST TO THE COAST.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...WEAK LOW PRESSURE OVER THE GA/SC COAST MON
MORNING WILL TRACK NORTHEAST ALONG A FRONT STALLED ACROSS THE AREA
DURING THE DAY. LOW LEVEL CONVERGENCE AHEAD AND EAST OF THIS LOW
WILL HAVE PLENTY OF DEEP TROPICAL MOISTURE TO TAP INTO. PRECIPITABLE
WATER VALUES LATER MON TOP OUT AROUND 2.35 INCHES WHICH IS RIGHT
AROUND THE 99TH PERCENTILE FOR THIS TIME OF YEAR. WIDESPREAD HEAVY
RAIN IS EXPECTED ACROSS MUCH OF THE FORECAST AREA WITH ADDITIONAL
ENHANCEMENT AHEAD AND EAST OF THE LOW THANKS TO LIFT. EAST OF THE
LOWS TRACK SIGNIFICANT RAINFALL POTENTIAL WILL EXIST WITH RAINFALL
RATES OF 2.5 INCHES PER HOUR AND HIGHER POSSIBLE. DEEP SOUTHWEST
FLOW SHOULD KEEP STORM MOTION CLOSE TO 15 KT SO SLOW MOVING STORMS
WILL NOT BE A CONCERN BUT TRAINING COULD LEAD TO EXCESSIVE LOCALIZED
RAINFALL. GIVEN THE SO FAR SPOTTY NATURE OF CONVECTION THIS
AFTERNOON...LACK OF SIGNIFICANT RAINFALL IN THE LAST WEEK OR
SO...AND STORM MOTIONS GREATER THAN 10 KT DO NOT FEEL A NEED TO
RAISE AN AREA WIDE FLOOD WATCH AT THIS POINT IN TIME.
THE LOW SHOULD TRACK JUST INLAND OF THE COAST MON INTO MON NIGHT
PLACING COASTAL COUNTIES IN THE AREA FAVORED FOR HEAVIEST RAIN.
AREAS WEST OF THE LOW WILL STILL HAVE POTENTIAL FOR PERIODS OF HEAVY
RAIN BUT COVERAGE WILL BE A LITTLE LESS GIVEN THE SLIGHTLY LESS
FAVORABLE CONDITIONS...LIMITED CONVERGENCE AND WEAKER UPWARD
MOTION.
THE SURFACE LOW WILL START TO STRENGTHEN TUE AS IT LIFTS NORTHEAST.
THIS WILL HELP PUSH THE COLD FRONT OFF THE COAST AND USHER IN DRIER
AIR ALOFT. MID LEVEL RIDGE OVER THE SOUTHERN CONUS STARTS TO EXPAND
EAST AS THE PERIOD ENDS. LOW LEVEL MOISTURE TENDS TO LINGER BEHIND
FRONTS IN THESE SETUPS AND TUE MAY END UP ON THE CLOUDY
SIDE...ESPECIALLY ALONG THE NC COAST...WITH MOISTURE TRAPPED UNDER
THE BUILDING MID LEVEL RIDGE.
TEMPERATURES WILL RANGE FROM NEAR TO BELOW CLIMO. HIGHS WEST OF THE
LOW WILL END UP BELOW CLIMO MON BUT NEAR TO SLIGHTLY ABOVE CLIMO
TUE. ALONG THE COAST THE OPPOSITE WILL BE TRUE WITH HIGHS AROUND
CLIMO MON BUT NEAR TO SLIGHTLY BELOW CLIMO TUE OWING TO LINGERING
LOW CLOUD AND NORTHERLY FLOW. LOWS WILL REMAIN ABOVE CLIMO BOTH
NIGHTS WITH CLOUD COVER IN PLACE MON NIGHT AND MIXING/LINGERING
CLOUDS TUE NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...WEAK HIGH PRESSURE WILL REMAIN AT THE SURFACE
WHILE RIDGE IN THE MID TO UPPER LEVELS EASES BACK UP INTO THE
CAROLINAS THROUGH MID WEEK WITH PLENTY OF DRY AIR AND SUBSIDENCE
ALOFT. MAY INCLUDE A VERY LOW END CHC OF SHWRS BY EARLY THURS BUT
OVERALL EXPECT PLENTY OF SUNSHINE WITH SOME LOCALIZED CU
DEVELOPMENT AND POSSIBLY A STRAY SHWR. BY LATE THURS INTO FRI CHC
OF PCP WILL INCREASE AS RIDGE ALOFT GETS SUPPRESSED FARTHER SOUTH
AS A SHORTWAVE BEGINS TO DIG DOWN AS IT RIDES ACROSS THE GREAT
LAKES. THIS SHORTWAVE WILL PUSH A COLD FRONT INTO THE CAROLINAS BY
FRI INTO SATURDAY WITH MORE WIDESPREAD SHWR AND TSTMS EXPECTED
HEADING INTO THE WEEKEND. AS THE SHORTWAVE LIFTS NORTHEAST A BROAD
TROUGH WILL REMAIN OVER THE EASTERN CONUS. THEREFORE THE FRONT MAY
BE SLOWER TO MOVE OFF THE COAST...BUT LATEST GFS DOES SHOW SOME
DRYING BY SAT NIGHT INTO SUNDAY WITH DEWPOINT TEMPS DROPPING INTO
THE 60S. PCP WATER VALUES WILL BE BELOW 1.5 INCHES ON WED BUT WILL
BE UP TO 2 INCHES OR GREATER BY THURS EVENING AND WILL NOT COME
BACK DOWN UNTIL SUNDAY. THE FORECAST SHOULD START OUT DRY AND END
DRIER...BUT LOOKING LIKE A WET FIRST HALF OF THE WEEKEND.
TEMPS WILL WARM UP AGAIN THROUGH MID WEEK IN GREATER SUNSHINE AND
SLIGHT RISE IN H5 HEIGHTS AND LOW LEVEL THICKNESSES FROM WED THROUGH
FRI. EXPECT TEMPS BACK UP AROUND 90 OR SO BY THURS AND FRI. BY
SATURDAY CLOUDS AND SHWRS WILL AFFECT THE TEMPS AND THEN SOME COOLER
AIR WILL BEGIN TO MOVE IN BEHIND FRONT LATER ON SATURDAY INTO
SUNDAY...KEEPING TEMPS IN THE LOWER 80S BOTH OVER THE WEEKEND.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...UNSETTLED WEATHER WILL PERSIST THROUGH THE PERIOD AS A
SURFACE LOW SLOWLY MOVES UP THE COAST AND MERGES WITH A STALLING
COLD FRONT OVER THE EASTERN CAROLINAS. THE LATEST HRRR RUNS DEPICT
SHRA/TSRA INCREASING IN COVERAGE THIS MORNING. THE HEAVIEST ACTIVITY
IS EXPECTED ALONG THE COAST...WHERE DOWNPOURS COULD BRIEFLY REDUCE
VSBYS TO MVFR/IFR LEVELS. POST-FRONTAL IFR CIGS ARE ALREADY
SPREADING OVER OUR INLAND ZONES...SO THE STRATUS AT KLBT/KFLO WILL
LIKELY PERSIST THROUGH THE MORNING HOURS. EXPECT MAINLY MVFR CIGS AT
THE COASTAL TERMS...THOUGH PERSISTENT RAINFALL COULD LOWER CIGS
BELOW 1KFT AT TIMES.
EXPECT MORE WIDESPREAD SHOWERS/ISO TSTMS DURING THE DAY AS THE LOW
MOVES UP THE COAST. MVFR CONDITIONS ARE EXPECTED TO PREVAIL DURING
THE AFTN WITH BRIEF AND LOCALIZED AREAS OF IFR. THERE IS STILL SOME
UNCERTAINTY REGARDING THE SPEED AND TRACK OF THE LOW...WHICH MAKES
FOR A LOWER CONFIDENCE WIND FORECAST. IT LOOKS LIKE THE COAST WILL
SEE SOUTHEAST WINDS 10 KT WITH HIGHER GUSTS POSSIBLE IF THE LOW
DEEPENS. MEANWHILE THE INLAND TERMS WILL KEEP NORTHEAST WINDS AOB 10
KT FOR MUCH OF THE DAY. PCPN WILL TAPER OFF FROM SW TO NE AS THE LOW
CONTINUES MOVING NORTHWARD...WITH WINDS SHIFTING TO THE NORTH ON THE
BACKSIDE OF THE LOW NEAR THE END OF THE PERIOD.
EXTENDED OUTLOOK...CHANCE OF SHOWERS EARLY TUESDAY. OTHERWISE VFR
WILL PREVAIL THROUGH THURSDAY. SHOWERS/TSTMS RETURN ON FRIDAY AS
ANOTHER COLD FRONT APPROACHES OUR CWA.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 PM SUNDAY...UPDATED WINDS DUE TO THE POSITIONING OF THE
FRONTAL BOUNDARY JUST INLAND FROM THE COAST. LATEST OBS AND HRRR
TRENDS INDICATE ESE-SSE DIRECTIONS ACROSS THE ILM WATERS DUE TO
THE MEANDERING OF THIS FRONT. PORTIONS OF IT MAY COME WITHIN 15
MILES OR LESS FROM THE IMMEDIATE COAST AT TIMES BUT MODELS REMAIN
ADAMANT IN KEEPING IT INLAND. SIGNIFICANT SEAS REMAIN 2 TO 4 FT
WITH WIND WAVES DOMINATING THE SEAS SPECTRUM...IE. DOMINANT
PERIODS AROUND 5 SECONDS.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...WEAK LOW PRESSURE MOVING NORTHEAST ALONG A
FRONT STALLED JUST WEST OF THE WATERS WILL BRING ABOUT AN INCREASE
IN SOUTHERLY FLOW MON. SOLID 20 KT IS LIKELY AND CANNOT RULE OUT A
BRIEF PERIOD WHERE SPEEDS WILL APPROACH 25 KT...IF THE LOW IS A BIT
STRONGER OR FASTER MOVING THAN CURRENTLY FORECAST. INCREASE IN WINDS
WILL BUILD SEAS TO 3 TO 5 FT MON AND MON NIGHT. ALTHOUGH THERE IS
POTENTIAL FOR A BRIEF PERIOD OF 6 FT...ESPECIALLY IF STRONGER
SOLUTION WERE TO VERIFY...WILL KEEP SEAS CAPPED AT 5 FT FOR NOW
GIVEN AMOUNT OF UNCERTAINTY.
SURFACE LOW MOVES OFF TO THE NORTHEAST TUE PUSHING THE FRONT EAST OF
THE WATERS AND SETTING UP OFFSHORE FLOW. EXITING LOW IS SLOW TO
STRENGTHEN AND THE GRADIENT BEHIND THE BOUNDARY IS NOT VERY WELL
DEFINED. OFFSHORE WINDS WILL BE AROUND 10 KT ON TUE BEFORE BACKING
TO WEST-SOUTHWEST AND DROPPING BELOW 10 KT TUE NIGHT. OFFSHORE
COMPONENT TO WINDS WILL KEEP SEAS 2 FT OR LESS DURING THE SECOND
HALF OF THE PERIOD.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...WEAK HIGH PRESSURE OVER THE WATERS WILL
MAINTAIN LIGHT AND VARIABLE WINDS COMING AROUND TO THE SOUTH BY
THURS BUT REMAINING 10 KTS OR LESS. BY LATE THURS INTO FRI THE
S-SW WINDS WILL INCREASE UP TO 15 KTS KICKING SEAS UP A BIT.
OVERALL EXPECT SEAS 3 FT OR LESS THROUGH MOST OF THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH/TRA
SHORT TERM...III
LONG TERM...RGZ
AVIATION...BJR/RJD
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1236 AM EDT MON SEP 8 2014
.SYNOPSIS...
A COLD FRONT WILL STALL JUST OFF THE EASTERN NORTH CAROLINA COAST
TONIGHT. SLOW MOVING LOW PRESSURE WILL LIFT NORTHEAST ALONG THE
STALLED FRONT MONDAY AND MONDAY NIGHT. THE LOW WILL FINALLY LIFT
NORTHEAST OF THE REGION TUESDAY WITH THE TRAILING COLD FRONT
GRADUALLY DISSIPATING AS IT DRIFTS OFF THE COAST. OFFSHORE HIGH
PRESSURE WILL DOMINATE WEDNESDAY AND THURSDAY WITH ANOTHER COLD
FRONT APPROACHING FROM THE WEST LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1235 AM MONDAY...BASED ON SURFACE OBSERVATIONS IT NOW
APPEARS THAT THE SURFACE FRONT HAS DRIFTED SOUTH INTO THE CAPE
FEAR REGION. EASTERLY POST FRONTAL FLOW NOW IS OCCURRING ACROSS
ALL OF EASTERN NC LATE TONIGHT WITH ONLY SPOTTY LIGHT SHOWERS
OCCURRING. JUST TO THE NORTH OF THE BOUNDARY THUNDERSTORMS HAVE
ERUPTED OVER ONSLOW COUNTY WITH ADDITIONAL CONVECTION DEVELOPING
IN THE CAPE FEAR REGION AND LIFTING NORTH. THE 3 KM HRRR MODEL
TAKES THIS PRECIPITATION NORTH ACROSS EASTERN NC LATE TONIGHT.
THUS WILL HAVE POPS INCREASING TO LIKELY ALL AREAS AFTER 06Z AS
THE MODEL DEVELOP A SLOW MOVING FRONTAL WAVE TO THE SOUTHWEST AND
MOVE THIS FEATURE TOWARD EASTERN NC ON MONDAY. NO CHANGES NEEDED
TO THE TEMPERATURE FORECAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 AM TUESDAY/...
MODEL TRENDS AND CONCENSUS SUGGEST THE BEST CHANCES FOR HEAVIER
PRECIPITATION WILL PUSH WESTWARD ALONG A DEVELOPING WEDGE FRONT ON
MONDAY. WILL CONTINUE CATEGORICAL POPS INLAND AND TAPER BACK
SLIGHTLY TO HIGH LIKELY POPS NEAR THE COAST. THERE WILL BE A
CONTINUED THREAT FOR HEAVY RAIN AND LOCALIZED FLOODING JUST ABOUT
ANYWHERE IN THE FORECAST AREA AND MAY EVENTUALLY NEED TO ISSUE
FLOOD ADVISORIES OR WARNINGS IF HEAVIER/STEADIER RAIN FOCUSES IN
ONE PARTICULAR AREA. HIGHS IN THE UPPER 70S TO LOWER 80S WITH
MAINLY CLOUDY SKIES AND WIDESPREAD PRECIPITATION.
&&
.LONG TERM /TUESDAY THROUGH MONDAY/...
AS OF 4 PM SUN...AN UNSETTLED/WET PERIOD EXPECTED TO CONTINUE
THROUGH TUE. THE COLD FRONT WILL REMAIN STALLED ACROSS THE AREA
MON NIGHT...WITH AN AREA OF LOW PRESSURE MOVING ALONG THE BOUNDARY
TUES INTO TUES NIGHT. THE STALLED BOUNDARY WILL BE A FOCUS FOR
OCCASIONAL HEAVIER PRECIPITATION WITH GOOD UPPER LEVEL DIVERGENCE
WITH THE REGION LOCATED IN THE RIGHT ENTRANCE OF THE UPPER JET
AND PIECES OF SHORT WAVE ENERGY PUSHING THRU THE LOW AMPLITUDE MID
LEVEL TROF OVER THE EASTERN STATES. MODEL PREFERENCES CONTINUE TO
SIDE WITH A GFE/ECMWF BLEND AS THE NAM CONTINUES TO SHOW A DEEPER
AND FASTER BIAS WITH THE SFC LOW TRACKING ACROSS THE AREA AND AS
SUCH HAVE INCREASED POPS MON NIGHT INTO TUES WITH A SLOWER
DEPARTURE OF THE LOW. FLOODING CONCERNS MAY CONTINUE INTO EARLY
TUES WITH ADDITIONAL RAINFALL AMOUNTS IN THE 1-2 INCH RANGE
POSSIBLE...WITH LOCALIZED HIGHER AMOUNTS POSSIBLE GIVEN THE HIGH
PWATS OF 2 TO 2.25 INCHES. HIGHS WILL BE HELD DOWN BY CLOUDS AND
PRECIP WITH MAX TEMPS UPPER 70S TO LOWER 80S TUE.
THE LOW IS PROGGED TO LIFT NE OF THE REGION TUES NIGHT WITH THE
FRONT FINALLY MOVING OFFSHORE WED...ALLOWING RIDGING/DEEP LAYER
DRYING TO BUILD INTO THE AREA MIDWEEK. ONLY ISOLATED SEA BREEZE
TYPE DIURNAL CONVECTION EXPECTED WED/THU AS SHORT WAVE RIDGE
SUPPRESSES MOST CONVECTION. RISING THICKNESS WILL RESULT IN HIGH
TEMPS MODERATING TO AT OR SLIGHTLY ABOVE NORMAL WED/THU...GENERALLY
HIGHS IN THE LOWER TO UPPER 80S.
ANOTHER COLD FRONT WILL MOVE INTO THE REGION LATE IN THE WEEK BUT
THE USUAL TIMING ISSUES CONTINUE REGARDING THE APPROACH AND
EVENTUAL PASSAGE OF THE FRONT. THERE IS ALMOST A 24 HR DIFFERENCE
BETWEEN THE 12Z GFS AND 12Z ECMWF IN REGARD TO THE TIMING OF THE
FRONT PUSHING SOUTH OF THE AREA LEADING TO BELOW AVERAGE
CONFIDENCE IN THE FORECAST DETAILS LATE IN THE WEEK. PRECIP COULD
BEGIN AS EARLY AS LATE THURS NIGHT WITH BEST CHANCES FRIDAY
AFTERNOON THROUGH SAT...THEN TAPER OFF FROM N TO S SUNDAY.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
SHORT TERM /THROUGH MONDAY NIGHT/...
AS OF 1235 AM MONDAY...SUB VFR CONDITIONS ARE EXPECTED THROUGH THE
TAF PERIOD IN WIDESPREAD PRECIPITATION...HEAVY AT TIMES WITH
ASSOCIATED LOW CEILINGS AND VISIBILITIES. CONDITIONS WILL TEND TO
BE VARIABLE BUT THINK IFR CEILINGS WILL PREVAIL INTO MONDAY
MORNING THEN COULD LIFT TO MVFR BEFORE DROPPING AGAIN LATE
MONDAY/MONDAY NIGHT AS SLOW MOVING LOW PRESSURE MOVES INTO THE
AREA.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 4 PM SUN...WIDESPREAD SHOWERS/THUNDERSTORMS WILL BRING
PERIODS OF MVFR AND OCCASIONAL IFR CONDITIONS DURING AN UNSETTLED
WEATHER PERIOD INTO TUE NIGHT AS A SFC FRONT STALLS OVER AND LOW
PRES LIFTS ACROSS REGION. THERE IS A POTENTIAL FOR RADIATION FOG
TUE NIGHT IF SKIES SUFFICIENTLY CLEAR AS LIGHT WINDS WILL PRODUCE
A DECENT FOG SETUP ESPECIALLY WITH A SATURATED GROUND. GRADUAL
DRYING IS EXPECTED WED AND THURS AS HIGH PRES BUILDS INTO THE AREA
WITH PRED VFR CONDITIONS AND ONLY ISOL DIURNALLY DRIVEN
CONVECTION...HOWEVER THERE IS A CHANCE OF MVFR CIGS LINGERING INTO
WED WITH WRAP-AROUND MOISTURE ACROSS THE AREA BEHIND THE DEPARTING
LOW.
&&
.MARINE...
SHORT TERM /TONIGHT/...
AS OF 1235 AM MONDAY...FRONT IS NOW SOUTH OF THE WATERS WITH ALL
OF THE NEAR-SHORE BUOYS NOW REPORTING N/NNE WINDS. SPEEDS ARE 15
KNOTS OR LESS AND GENERALLY 5 TO 10 KNOTS OVER ALL BUT THE FAR
NORTHERN SECTIONS. PER LATEST 3 KM HRRR...WINDS SHOULD REMAIN NE/E
THROUGH THE NIGHT WITH SEAS AT 2 TO 4 FEET. THE PRESSURE GRADIENT
WILL TIGHTEN SOUTH OF THE FRONT AS LOW PRESSURE RIDES NE ALONG THE
BNDRY MONDAY AND MAY REACH 15-20 KT MONDAY AFTERNOON OVER SOUTHERN
AND CENTRAL WATERS. SEAS BUILD 3-5 FT IN RESPONSE TO THE WIND
INCREASE.
LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 4 PM SUN...A FRONTAL BOUNDARY WILL REMAIN STALLED ACROSS
EASTERN NC WITH AREA OF LOW PRESSURE SLOWLY LIFTING ALONG THE
FRONT MON NIGHT INTO WED. BELOW NORMAL CONFIDENCE IN THE MARINE
FORECAST AS MODELS NOT IN BEST AGREEMENT WITH TIMING AND
STRENGTH OF THE LOW. PREFERRED MODELS ARE A BLEND OF THE GFS/ECMWF
WHICH IS SLOWER AND WEAKER WITH THE LOW AND THE FORECAST GENERALLY
FOLLOWS THIS TREND WITH WINDS AROUND 10-20 KT. IF THE NAM ENDS UP
VERIFYING WINDS COULD BE SIGNIFICANTLY STRONGER...AND CURRENTLY
SHOWS WINDS AS HIGH AS 20-30 KT AHEAD OF THE LOW MON NIGHT. USED A
BLEND OF THE NWPS AND WAVEWATCH III WITH SEAS PRIMARILY AROUND 3-5
FT...HOWEVER IF THE NAM VERIFIES HIGHER SEAS WILL BE LIKELY. THE
LOW TRACKS OFF THE NC COAST WED WITH WINDS BECOMING LIGHT NW AS
PRESSURE GRADIENT BECOMES WEAK ALONG THE COAST. WINDS GENERALLY
LESS THAN 10KT WILL CONTINUE WED NIGHT INTO EARLY THU...BECOMING
S/SW AGAIN 10-15KT BY LATE THU AFTERNOON AHEAD OF ANOTHER COLD
FRONT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BTC
NEAR TERM...CTC/JME
SHORT TERM...BTC
LONG TERM...BTC/SK
AVIATION...JME/SK
MARINE...CTC/BTC/JME/SK
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1140 PM CDT SUN SEP 7 2014
.AVIATION...
/06Z TAFS/
Patchy stratus with MVFR ceilings possible daybreak into into mid
morning. Otherwise light winds and mid level clouds will prevail
overnight with south winds increasing to 5-10 KTS mid morning. With
light winds and evening rainfall near KSOA and KJCT, there is the
potential for patchy fog, mainly MVFR, near sunrise. However, mid
level clouds and morning stratus may limit widespread formation.
&&
.PREV DISCUSSION... /ISSUED 635 PM CDT SUN SEP 7 2014/
AVIATION...
/00Z TAFS/
Thunderstorm outflow boundary will move through KSJT around 0030Z,
temporarily shifting winds to the south with gusts to 20 KTS.
Thunderstorms will be in the vicinity until 2Z. With low levels of
the atmosphere remaining moist, stratus expected with MVFR CIGS late
tonight, beginning at climatologically favorable times and
scattering out mid to late Monday morning.
PREV DISCUSSION... /ISSUED 313 PM CDT SUN SEP 7 2014/
SHORT TERM...
(Tonight and tomorrow)
The quasi-stationary front is currently analyzed very near the
southern border of the CWA, roughly along a line from Sheffield, to
Rock Springs, to San Antonio. Skies cleared by midday across the
I-10 corridor, allowing temperatures to warm into the mid 80s.
MLCAPE values around 1000-1500 J/kg are present from Ozona to
Junction per the RAP Mesoanalysis, but CINH is no longer a concern
in this area. Scattered showers and thunderstorms have developed in
the vicinity of this boundary and will move to the northwest during
the afternoon and evening hours. Rain chances tonight will primarily
be limited to locations south of a Sterling City to Brownwood line.
The primary concern will be locally heavy rainfall given the slow
storm motions and precipitable water values around 1.75". This could
result in minor flooding, mainly in urban areas. Low temperatures
tonight should be in the upper 60s.
On Monday, we`ll maintain a moist airmass across West Central TX.
Precipitable water values are progged to remain at or above 1.60",
but the surface boundary is progged to wash out as southerly flow
resumes across the region. The loss of a low-level forcing mechanism
will limit rain chances. However, with temperatures warming into the
lower 90s, we should still see diurnal isolated convection across
the area. The best rain chances will be over the northwest Hill
Country, but isolated showers and thunderstorms will be included for
much of the area east of a Sonora, to San Angelo, to Sweetwater
line.
Johnson
LONG TERM...
(Tomorrow night through Sunday)
A cold front will bring a chance of showers and thunderstorms and
cooler temperatures for the latter part of the work week...
Above normal temperatures are forecast on Tuesday, with highs
ranging from the lower to mid 90s across the Interstate 10 corridor,
to the mid to upper 90s across the Big Country. Overnight lows will
be int he mid 70s. In the meantime, an upper level trough will move
into the Northern Rockies, and then eventually into the Northern
Plains, sending a cold front into the northern Big Country Wednesday
evening. Ahead of the cold front, compressional heating will result
in unseasonably hot temperatures on Wednesday. Highs will generally
be in the mid to upper 90s.
Models continue to have timing differences with regard to the
aforementioned cold front. Both the ECMWF and the GFS bring a front
into the Big Country Wednesdays night, then eventually slowly move
it through much of the rest of West Central Texas during the day
Thursday. Showers and thunderstorms are forecast to develop along
the front, with the best chance across the Big Country initially,
then better chances spreading south into much of the rest of the
area Thursday into Thursday night. High temperatures on Thursday
will be dependent on the timing of the front and any associated
rainfall. For now, the forecast reflects highs in the mid 80s across
the Big Country to the lower 90s across the Interstate 10 corridor.
Beyond Thursday, the GFS pushes the front through the area, while
the ECMWF dissipates the boundary, with a stronger cold front moving
through during the day on Friday. For now, the forecast was geared
toward the faster GFS solution, with PoPs decreasing from north to
south Friday. If the ECMWF solution were to verify, higher PoPs
would linger into Friday/Friday night. Highs on Friday were trended
down, given the expected cloud cover and cold air advection. Highs
will range from the lower 70s in the Big Country to near 80 along
the Interstate 10 corridor. These temperatures may eventually need
to be trended down a bit. A slow warm up is forecast into next
weekend.
Daniels
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 66 91 71 96 75 / 10 10 5 5 5
San Angelo 67 92 71 96 75 / 20 10 5 5 5
Junction 68 90 71 95 74 / 20 20 10 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/04
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
445 AM PDT MON SEP 8 2014
.SYNOPSIS...
MONSOONAL MOISTURE WILL REMAIN IN PLACE INTO TUESDAY WITH MAINLY
AFTERNOON AND EARLY EVENING THUNDERSTORMS IN THE MOUNTAINS AND
DESERTS THROUGH TUESDAY AND ALSO IN THE INLAND EMPIRE THIS
AFTERNOON. DRYING WITH SEASONAL TEMPERATURES IS EXPECTED FOR
WEDNESDAY INTO NEXT WEEKEND. WEAK EASTERLY MID LEVEL FLOW COULD
BRING SOME MOISTURE AND AFTERNOON CLOUDS TO THE MOUNTAINS AT TIMES
FROM WEDNESDAY INTO NEXT WEEKEND.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
RADAR IMAGERY SHOWS WIDELY SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS DEVELOPING EARLY THIS MORNING ACROSS SOUTHERN
CALIFORNIA. GENERALLY FROM THE SAN DIEGO COUNTY COASTAL WATERS
ACROSS FAR NORTHERN SAN DIEGO COUNTY AND THE CENTRAL COACHELLA
VALLEY NORTHWARD. THIS IS AN AREA OF DIFLUENCE AHEAD THE TROUGH OF
LOW PRESSURE MOVING SOUTHWARD ALONG THE NORTHERN CALIFORNIA COAST.
THE 00Z ECMWF SHOWED SOME INDICATIONS OF THIS POSSIBILITY VERSUS
PREVIOUS RUNS AND THE 08Z RUN OF THE EXPERIMENTAL NCEP VERSION OF
THE HRRR TAKES THE CONVECTION OVER THE NORTHERN COACHELLA VALLEY AND
MOVES IT NORTHEASTWARD THIS MORNING.
THE COVERAGE OF THIS ELEVATED CONVECTION IS LIMITED ENOUGH AND THE
MOVEMENT TOWARD THE NORTHEAST AND EAST SUFFICIENT TO MOST LIKELY
KEEP RAINFALL COVERAGE EARLY THIS MORNING LIMITED AND NOT TOO HEAVY.
THE GREATEST POTENTIAL FOR LOCALLY HEAVY RAINFALL AND FLASH FLOODING
EARLY THIS MORNING WILL BE OVER THE DESERTS...ESPECIALLY THE
NORTHERN AND CENTRAL COACHELLA VALLEY NORTHEASTWARD.
HOWEVER...WITH DAYTIME HEATING THE FOCUS IS EXPECTED TO SHIFT
FARTHER INLAND FROM LATE MORNING THROUGH THE AFTERNOON AND EARLY
EVENING. PRECIPITABLE WATER VALUES REMAIN NEAR 2.4 INCHES IN THE
LOWER DESERTS AND 1.7 INCHES WEST OF THE MOUNTAINS. TODAY...SEA
BREEZE CONVERGENCE BOUNDARIES ARE EXPECTED TO DEVELOP NEAR OR
SLIGHTLY INLAND OF THE MOUNTAIN RIDGE TOPS...THEN MIGRATE INTO THE
DESERTS DURING THE AFTERNOON WITH THE SEA BREEZE. THUNDERSTORMS ARE
EXPECTED TO DEVELOP IN THE MOUNTAINS DURING THE LATE MORNING OR
EARLY AFTERNOON...THEN MIGRATE TOWARD THE DESERTS DURING THE
AFTERNOON THROUGH EARLY EVENING. THUNDERSTORMS MAY ALSO DEVELOP IN
PORTIONS OF THE INLAND EMPIRE IN THE AFTERNOON ALONG THE ELSINORE
CONVERGENCE ZONE. GIVEN THE HIGH MOISTURE CONTENT OF THE ATMOSPHERE
AND SLOW MOVEMENT OF STORMS...THERE IS A HIGH POTENTIAL FOR HEAVY
RAINFALL AND FLASH FLOODING FROM THUNDERSTORMS THIS
AFTERNOON...ESPECIALLY ALONG THE EAST SLOPES OF THE MOUNTAINS AND
ADJACENT DESERT AREAS. THE 06Z 4-KM VERSION OF THE NAM APPEARS TO
SHOW THIS WELL.
FOR LATE TONIGHT AND EARLY TUESDAY...MOISTURE FROM THE MID LEVEL
REMNANTS OF FORMER HURRICANE NORBERT (NOW A POST TROPICAL LOW) WILL
MOVE ACROSS NORTHERN BAJA AND FAR SOUTHERN CALIFORNIA. THE 06Z NAM
DOES DEVELOP SOME PRECIPITATION LATE TONIGHT INTO EARLY
TUESDAY...MAINLY IN PORTIONS OF SAN DIEGO COUNTY.
WHILE DRYING WILL BE UNDERWAY ON TUESDAY...THUNDERSTORMS ARE
EXPECTED DURING THE AFTERNOON OVER THE MOUNTAINS AND
DESERTS...MAINLY FROM THE MOUNTAIN RIDGE TOPS INTO THE DESERTS.
DECREASING MOISTURE AND A LITTLE FASTER STORM MOVEMENT SHOULD
REDUCE THE POTENTIAL FOR FLASH FLOODING A LITTLE.
DRIER WEATHER WITH SEASONAL TEMPERATURES WILL PREVAIL FOR WEDNESDAY
INTO NEXT WEEKEND. WEAK EASTERLY MID LEVEL FLOW COULD BRING SOME
MOISTURE AND AFTERNOON CLOUDS TO THE MOUNTAINS AT TIMES FROM
WEDNESDAY INTO NEXT WEEKEND.
&&
.AVIATION...
080900Z...COAST/VALLEYS...VFR CONDITIONS CONDITIONS WILL CONTINUE
THROUGH THIS EVENING...WITH SCT/BKN MID AND HIGH CLOUDS. THE CLOUD
DECK MAY LOWER TO BETWEEN 2000-4000 FT MSL AFT 09/0300Z.
MTNS/DESERTS...VFR CONDITIONS WILL CONTINUE THROUGH THIS MORNING.
HOWEVER...AFT 08/1800Z...CUMULUS WILL BEGIN TO BUILD OVER THE HIGHER
TERRAIN WITH BASES AROUND 6000 FT MSL AND TOPS ABV 25000 FT MSL.
ISOLATED TO SCATTERED THUNDERSTORMS WILL DEVELOP OVER THE RIDGE
TOPS...EVENTUALLY PUSHING INTO THE DESERTS. THESE STORMS WILL BE
CAPABLE OF PRODUCING GUSTY ERRATIC WINDS...STRONG
UP/DOWNDRAFTS...REDUCED VIS FROM HEAVY RAIN AND LIGHTNING.
CONDITIONS WILL IMPROVE BY THIS EVENING.
&&
.MARINE...THERE IS NO SIGNIFICANT MARINE WEATHER EXPECTED THROUGH
SATURDAY.
&&
.BEACHES...
200 AM...ELEVATED SURF AND STRONG RIP CURRENTS WILL CONTINUE THROUGH
TONIGHT DUE TO A LONG-PERIOD SOUTH SOUTHEAST SWELL. SETS TO 7 FEET
WILL BE POSSIBLE...MAINLY ON SOUTHERLY FACING BEACHES. A BEACH
HAZARD STATEMENT REMAINS IN EFFECT THROUGH TONIGHT.
&&
.SKYWARN...
SKYWARN ACTIVATION IS REQUESTED FOR THE LATE MORNING THROUGH EARLY
EVENING TODAY FOR THE MOUNTAINS...DESERTS...AND INLAND EMPIRE.
SPOTTER ACTIVATION MAY BE NEEDED AGAIN TUESDAY AFTERNOON FOR THE
MOUNTAINS AND DESERTS.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR THE APPLE AND
LUCERNE VALLEYS...COACHELLA VALLEY...RIVERSIDE COUNTY
MOUNTAINS...SAN BERNARDINO COUNTY MOUNTAINS...SAN DIEGO COUNTY
DESERTS...SAN DIEGO COUNTY MOUNTAINS.
BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT FOR THE BEACHES IN
THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO COUNTY COASTAL
AREAS.
FLASH FLOOD WATCH FROM 10 AM PDT THIS MORNING THROUGH THIS
EVENING FOR THE SAN BERNARDINO AND RIVERSIDE COUNTY
VALLEYS-THE INLAND EMPIRE.
PZ...NONE.
&&
$$
PUBLIC...17
AVIATION/MARINE/BEACHES...JT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
517 AM MDT MON SEP 8 2014
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 411 AM MDT MON SEP 8 2014
MODEL DATA CONTINUES TO SHOW EXCELLENT CONTINUITY REGARDING THE
INTERACTION OF UPPER TROUGH ALONG THE CALIFORNIA COAST AND
MOISTURE PLUME (WHICH INCLUDES THE REMAINS OF NORBERT). MOISTURE
PLUME ARCS FROM THE LOWER COLORADO RIVER BASIN INTO SW UTAH...
EVENTUALLY SPREADING EAST INTO WRN COLORADO AS THE DAY PROGRESSES
TODAY. IN THE SHORT TERM OUTLOOK...THE HRRR SHOWS THE AREA OF PCPN
OVER PARTS OF SW COLORADO (OR WRN PORTION OF THE SAN JUAN
MOUNTAINS) WILL SHIFT NORTHWARD EARLY THIS MORNING AND BE
POSITIONED OVER THE I70 CORRIDOR AROUND DAYBREAK. HAVE NOT SEEN
THIS NORTHWARD TREND YET...BUT SEEMS REASONABLE AS ISENTROPIC
UPGLIDE AND INCREASING MOISTURE FROM THE WEST ACCOUNTS FOR AN
INCREASING CHANCE OF RAIN. SPECIFIC HUMIDITIES AT 700 MB IS QUITE
HIGH WITH VALUES RANGING FROM 8 TO 10 G/KG. PRECIPITABLE WATER AT
KGJT IS PROGGED TO BE 1.25 INCHES BY 00Z THIS EVENING (PER RAP13)...
WHICH IS PLUS 3 STANDARD DEVIATIONS ABOVE NORMAL. USED THE DAY 1
EXCESSIVE RAINFALL OUTLOOK TO FINE TUNE THE FLASH FLOOD WATCH.
THE ONLY AREAS OUTSIDE THE EXCESSIVE RAINFALL IS PARTS OF NE
UTAH...WRN MOFFAT COUNTY AND ARCHULETA COUNTY AND THE ERN EDGE OF
OUR FORECAST AREA.
TONIGHT DEEP MOISTURE CONTINUES TO ADVECT IN FROM THE SW UP TO 1.3
INCHES IN SE UTAH AND EVEN UP TO 1.6 INCHES IN THE 00Z NAM12. THIS
IS VERY HIGH FOR EARLY SEPTEMBER...GREATER THAN TWO STANDARD
DEVIATIONS ABOVE NORMAL. THE SATURATED VERTICAL PROFILE WITH WET
BULB ZERO/ICE PRODUCTION LEVEL AROUND 10KFT WILL NOT NEED DEEP
CONVECTIVE CELLS TO PRODUCE HEAVY RAINFALL. SO THIS WILL MAKE THE
RADAR OBSERVATIONS DIFFICULT TO CAPTURE SOME OF THE HEAVIEST
SHOWERS OCCURRING IN THE FOUR CORNERS REGION. STORM MOTION WILL BE
QUICK THOUGH TO THE ENE AT 20KTS INCREASING TO 30 KTS BY EARLY
TUESDAY MORNING. SOME SHOWERS WILL BE MIXING THESE WINDS DOWN TO
THE SURFACE. THIS IS NOT CAPTURED WELL IN MOS GUIDANCE.
TUESDAY THE BROAD TROUGH WORKS THROUGH THE GREAT BASIN AND INTO
THIS CWA BY LATE AFTERNOON. GRADIENT WINDS VEERS FROM SW TO W AND
INCREASE TO 30 TO 50 KTS IN THE 0-6KM LAYER. THIS WEST FLOW WILL
BEGIN TO ERODE MOISTURE IN THE MID LEVELS ADDING TO AFTERNOON
INSTABILITY. PRECIP WATER VALUES FALL BELOW ONE INCH IN THE
AFTERNOON. JET SUPPORT PASSES THROUGH WYOMING BUT POTENTIAL VORT
FIELDS SHOW SOME FORCING ACROSS THE NORTH. SO CHANCES FOR STRONGER
CONVECTIVE CELLS INCREASE TUESDAY AFTERNOON ESPECIALLY OVER THE
NORTH. GUSTY WINDS AND SMALL HAIL ARE POSSIBLE. HEAVIER RAIN
SHOWERS PERSIST IN THE SOUTH. EXPECT A COOL DAY UNDER WIDESPREAD
CLOUDS AND SHOWERS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 411 AM MDT MON SEP 8 2014
TUESDAY NIGHT...WITH TROUGH PASSAGE OVERNIGHT THE FLOW VEERS TO A
DRIER NW AND PRECIP WATER VALUES DROP TO AROUND 0.5 INCHES FOR ALL
BUT THE SOUTHERN MOST ZONES. SHOWERS ARE EXPECTED TO ERODE FROM
WEST TO EAST THROUGH THE EVENING. THERE MAY BE SOME THREAT OF
LOCALIZED MORNING FOG.
WEDNESDAY-WEDNESDAY NIGHT...A FEW AFTERNOON SHOWERS MAY FORM IN
THE EASTERN MOUNTAINS WEDNESDAY AFTERNOON IN RESIDUAL MOISTURE.
OTHERWISE PLENTY OF SUN RETURNS TO THE FORECAST AREA. TEMPERATURES
REMAIN BELOW NORMAL. LIGHT WINDS AND CLEARING SKIES WEDNESDAY
NIGHT SHOULD ALLOW FOR MODERATE TO STRONG SURFACE BASED INVERSIONS
AND COOL OVERNIGHT LOW TEMPERATURES.
THURSDAY THROUGH SUNDAY...DRY AND STABLE NORTHWEST FLOW IS
EXPECTED TO PREVAIL THROUGH THIS PERIOD. RIDGE AXIS AMPLIFIES OVER
THE WRN STATES WITH TIME. AFTERNOON TEMPS WILL HAVE RECOVERED FROM
THE RAIN COOLDED AIR MASS WITH PLENTY OF DAYTIME SUNSHINE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 517 AM MDT MON SEP 8 2014
DETERIORATING CONDITIONS TODAY AS SCATTERED -SHRA/-TSRA WILL
EXPAND IN AREAL COVERAL TODAY AND BECOME NUMEROUS THIS AFTERNOON.
FREQUEST -SHRA WITH EMBEDDED -TSRA IS EXPECTED TONIGHT WITH LOCAL
4SM +SHRA POSSIBLE. CIGS/VIS MAY LOWER TO IFR/MVFR FROM THE
STRONGEST SHOWERS OR THUNDERSTORMS...ESPECIALLY AT MOUNTAIN TAF
SITES.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH FROM 9 AM MDT THIS MORNING THROUGH TUESDAY
EVENING FOR COZ002>014-017>022.
UT...FLASH FLOOD WATCH FROM 9 AM MDT THIS MORNING THROUGH TUESDAY
EVENING FOR UTZ022-025-027>029.
&&
$$
SHORT TERM...PF/JOE
LONG TERM...JOE/PF
AVIATION...PF
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
411 AM MDT MON SEP 8 2014
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 411 AM MDT MON SEP 8 2014
MODEL DATA CONTINUES TO SHOW EXCELLENT CONTINUITY REGARDING THE
INTERACTION OF UPPER TROUGH ALONG THE CALIFORNIA COAST AND
MOISTURE PLUME (WHICH INCLUDES THE REMAINS OF NORBERT). MOISTURE
PLUME ARCS FROM THE LOWER COLORADO RIVER BASIN INTO SW UTAH...
EVENTUALLY SPREADING EAST INTO WRN COLORADO AS THE DAY PROGRESSES
TODAY. IN THE SHORT TERM OUTLOOK...THE HRRR SHOWS THE AREA OF PCPN
OVER PARTS OF SW COLORADO (OR WRN PORTION OF THE SAN JUAN
MOUNTAINS) WILL SHIFT NORTHWARD EARLY THIS MORNING AND BE
POSITIONED OVER THE I70 CORRIDOR AROUND DAYBREAK. HAVE NOT SEEN
THIS NORTHWARD TREND YET...BUT SEEMS REASONABLE AS ISENTROPIC
UPGLIDE AND INCREASING MOISTURE FROM THE WEST ACCOUNTS FOR AN
INCREASING CHANCE OF RAIN. SPECIFIC HUMIDITIES AT 700 MB IS QUITE
HIGH WITH VALUES RANGING FROM 8 TO 10 G/KG. PRECIPITABLE WATER AT
KGJT IS PROGGED TO BE 1.25 INCHES BY 00Z THIS EVENING (PER RAP13)...
WHICH IS PLUS 3 STANDARD DEVIATIONS ABOVE NORMAL. USED THE DAY 1
EXCESSIVE RAINFALL OUTLOOK TO FINE TUNE THE FLASH FLOOD WATCH.
THE ONLY AREAS OUTSIDE THE EXCESSIVE RAINFALL IS PARTS OF NE
UTAH...WRN MOFFAT COUNTY AND ARCHULETA COUNTY AND THE ERN EDGE OF
OUR FORECAST AREA.
TONIGHT DEEP MOISTURE CONTINUES TO ADVECT IN FROM THE SW UP TO 1.3
INCHES IN SE UTAH AND EVEN UP TO 1.6 INCHES IN THE 00Z NAM12. THIS
IS VERY HIGH FOR EARLY SEPTEMBER...GREATER THAN TWO STANDARD
DEVIATIONS ABOVE NORMAL. THE SATURATED VERTICAL PROFILE WITH WET
BULB ZERO/ICE PRODUCTION LEVEL AROUND 10KFT WILL NOT NEED DEEP
CONVECTIVE CELLS TO PRODUCE HEAVY RAINFALL. SO THIS WILL MAKE THE
RADAR OBSERVATIONS DIFFICULT TO CAPTURE SOME OF THE HEAVIEST
SHOWERS OCCURRING IN THE FOUR CORNERS REGION. STORM MOTION WILL BE
QUICK THOUGH TO THE ENE AT 20KTS INCREASING TO 30 KTS BY EARLY
TUESDAY MORNING. SOME SHOWERS WILL BE MIXING THESE WINDS DOWN TO
THE SURFACE. THIS IS NOT CAPTURED WELL IN MOS GUIDANCE.
TUESDAY THE BROAD TROUGH WORKS THROUGH THE GREAT BASIN AND INTO
THIS CWA BY LATE AFTERNOON. GRADIENT WINDS VEERS FROM SW TO W AND
INCREASE TO 30 TO 50 KTS IN THE 0-6KM LAYER. THIS WEST FLOW WILL
BEGIN TO ERODE MOISTURE IN THE MID LEVELS ADDING TO AFTERNOON
INSTABILITY. PRECIP WATER VALUES FALL BELOW ONE INCH IN THE
AFTERNOON. JET SUPPORT PASSES THROUGH WYOMING BUT POTENTIAL VORT
FIELDS SHOW SOME FORCING ACROSS THE NORTH. SO CHANCES FOR STRONGER
CONVECTIVE CELLS INCREASE TUESDAY AFTERNOON ESPECIALLY OVER THE
NORTH. GUSTY WINDS AND SMALL HAIL ARE POSSIBLE. HEAVIER RAIN
SHOWERS PERSIST IN THE SOUTH. EXPECT A COOL DAY UNDER WIDESPREAD
CLOUDS AND SHOWERS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 411 AM MDT MON SEP 8 2014
TUESDAY NIGHT...WITH TROUGH PASSAGE OVERNIGHT THE FLOW VEERS TO A
DRIER NW AND PRECIP WATER VALUES DROP TO AROUND 0.5 INCHES FOR ALL
BUT THE SOUTHERN MOST ZONES. SHOWERS ARE EXPECTED TO ERODE FROM
WEST TO EAST THROUGH THE EVENING. THERE MAY BE SOME THREAT OF
LOCALIZED MORNING FOG.
WEDNESDAY-WEDNESDAY NIGHT...A FEW AFTERNOON SHOWERS MAY FORM IN
THE EASTERN MOUNTAINS WEDNESDAY AFTERNOON IN RESIDUAL MOISTURE.
OTHERWISE PLENTY OF SUN RETURNS TO THE FORECAST AREA. TEMPERATURES
REMAIN BELOW NORMAL. LIGHT WINDS AND CLEARING SKIES WEDNESDAY
NIGHT SHOULD ALLOW FOR MODERATE TO STRONG SURFACE BASED INVERSIONS
AND COOL OVERNIGHT LOW TEMPERATURES.
THURSDAY THROUGH SUNDAY...DRY AND STABLE NORTHWEST FLOW IS
EXPECTED TO PREVAIL THROUGH THIS PERIOD. RIDGE AXIS AMPLIFIES OVER
THE WRN STATES WITH TIME. AFTERNOON TEMPS WILL HAVE RECOVERED FROM
THE RAIN COOLDED AIR MASS WITH PLENTY OF DAYTIME SUNSHINE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 102 4 PM MDT SUN SEP 7 2014
AN AREA OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUES TO DRIFT
SLOWLY EAST FROM ABAJO MOUNTAINS THROUGH MOST OF SOUTHWESTERN
COLORADO. THIS AREA OF SHOWERS WILL DIMINISH AFTER MIDNIGHT. AN
ISOLATED SHOWER/THUNDERSTORM WILL STILL BE POSSIBLE INTO THE
MORNING HOURS ON MONDAY. AS MOISTURE INCREASES FROM THE SOUTH ON
MONDAY THE THREAT OF SHOWERS AND THUNDERSTORMS WILL PUSH INTO THE
SCATTERED CATEGORIES BY MONDAY AFTERNOON WITH MORE WIDESPREAD
COVERAGE BY MONDAY NIGHT. AT THE ONSET...GUSTY OUTFLOW WINDS TO 45
MPH WILL BE POSSIBLE. LOCALLY HEAVY RAIN WILL RESULT IN SCT MVFR
CONDITIONS WITH ISOLATED IFR WHICH WILL CONTINUE AND INCREASE IN
COVERAGE BY MONDAY NIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH FROM 9 AM MDT THIS MORNING THROUGH TUESDAY
EVENING FOR COZ002>014-017>022.
UT...FLASH FLOOD WATCH FROM 9 AM MDT THIS MORNING THROUGH TUESDAY
EVENING FOR UTZ022-025-027>029.
&&
$$
SHORT TERM...PF/JOE
LONG TERM...JOE/PF
AVIATION...MPM
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
917 AM EDT MON SEP 8 2014
.SYNOPSIS...
HIGH PRESSURE OVER NEW ENGLAND WILL STRENGTHEN AS IT MOVES TO THE
MARITIMES TONIGHT. MEANWHILE LOW PRESSURE WILL BE MOVING SLOWLY
NORTHEAST FROM THE COASTAL CAROLINAS AND PASSING OUT TO SEA EAST OF
THE MID ATLANTIC COAST WEDNESDAY NIGHT OR THURSDAY. A COLD FRONT
WILL CROSS OUR AREA FROM THE NORTHWEST LATE THURSDAY OR FRIDAY.
STRONG HIGH PRESSURE OVER THE PLAINS STATES FRIDAY BUILDS INTO THE
NORTHEAST FOR THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BASED ON LATEST RADAR AND HRRR GUID HAVE REMOVED POPS ACRS THE LWR
DELMARVA IN THE REAL NEAR TERM AND LOWERED POPS A TAD LATER TODAY.
WILL SEE HOW THINGS DEVELOP FOR THE LATE MRNG UPDATE. OTHERWISE,
ADJUSTED CLOUD COVER DOWNWARD UP NORTH, WHERE STLT IMAGERY SHOWED
IT WAS CLEAR.
WEAK LOW PRESSURE DEVELOPING OFF THE SE US COAST TODAY AND
PERSISTENT HIGH PRESSURE ACROSS ERN NEW ENGLAND AND SE CANADA WILL
KEEP A ONSHORE FLOW DIRECTED ACROSS OUR AREA TODAY. HIGH/MID LEVEL
CLOUDINESS ALREADY EXISTS ACROSS THE S/E HALF OF THE AREA...AND IT
WILL CONTINUE TO LOWER/THICKEN TODAY. WITH REGARDS TO PCPN
POTENTIAL...WE HAVE SIDED A BIT CLOSER TO THE GFS WHICH BRINGS SOME
SMALL CHC FOR SHOWERS TO THE DELMARVA LATER TODAY...OVERALL OUR POPS
ARE A BIT LESS THAN THE PREVIOUS FCST. THE 00Z EC HAS SOME LIGHTER
SHOWERS DEVELOPING FURTHER NORTH AND EARLIER THAN THE GFS...BUT THIS
DOES NOT LOOK RIGHT...SO WE WILL KEEP THE IDEAS FROM THE THE EARLIER
FCST...JUST SLOWED DOWN A BIT. TEMPS...MOSTLY MAV BUT BLENDED IN
WITH EARLIER FCST TOO.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
MUCH LIKE THE NEAR TERM...HIGHER PCPN CHC ESPECIALLY S/E WHERE
LIKELY/LOW CATEGORICAL POPS ARE EXPECTED...NO PCPN EXPECTED N/W.
WEAK LOW WILL SLIDE A BIT UP THE COAST AND KEEP THE ONSHORE FLOW
ACROSS THE AREA...CLOUDS ARE EXPECTED ACROSS MOST ALL AREAS...LESS
N/W. WINDS MOSTLY ERLY AROUND 10 KTS.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AN AMENDED-CORRECTED SET OF ZONES WAS SENT AT 510AM TO MORE
ACCURATELY ACCOUNT FOR THE GRIDDED 330 AM FORECAST EXPECTATIONS
BETWEEN TUESDAY AND SATURDAY.
500 MB: A SLOW MOVING TROUGH MOVES EAST ACROSS THE MID ATLANTIC
STATES TUESDAY AND WEDNESDAY. THEREAFTER...TWO STRONG SHORT WAVES
MOVE THROUGH THE UPPER MIDWEST FROM LATE THURSDAY THROUGH NEXT
SUNDAY.
TEMPERATURES: THE FIRST WEEK OF SEPTEMBER HAS AVERAGED WELL ABOVE
NORMAL...ON THE ORDER OF ABOUT 6 DEGREES. NEAR NORMAL TEMPERATURES
TUESDAY SHOULD WARM TO MORE THAN 5 DEGREES ABOVE NORMAL THURSDAY
THEN COOL TO SLIGHTLY BELOW NORMAL OVER THE WEEKEND.
FORECAST BASIS: UNLESS OTHERWISE NOTED THE LONG TERM PERIOD OF THIS
FORECAST IS GENERALLY BASED ON A 50 50 BLEND OF THE 00Z/8 NAM/GFS
MOS FOR THE PERIOD TUESDAY - WEDNESDAY...THE 00Z/8 GFS MOS WEDNESDAY
NIGHT AND THURSDAY...THEN THEREAFTER (THURSDAY NIGHT ONWARD) THE
0443Z/8 WPC GRIDDED GUIDANCE WHICH AT TIMES IS BLENDED 50 50 WITH
THE 00Z/8 MEXMOS. ALL THIS IS EVENTUALLY CHECKED AGAINST THE
00Z/8 ECMWF TO SEE IF WE`RE IN THE BALLPARK WITH ECMWF CYCLICALLY
PERSISTENT 18Z 2 METER TEMPERATURES. THE PRECIPITATION PROBABILITY
GUIDANCE IS CHECKED AGAINST THE 21Z/7 SREF 3HRLY POPS FOR .01
THROUGH 12Z THURSDAY AND THEREAFTER THE 00Z/8 GEFS 6HR POPS FOR
0.05
THE DAILIES BELOW...
TUESDAY INTO WEDNESDAY...IT MAY BE NASTY AT TIMES ALONG THE DE COAST
AND THE S NJ COAST WITH GUSTY EAST NORTHEAST WINDS AND BANDS OF
SHOWERS SWEEPING NWWD INLAND IN A TROWAL ENVIRONMENT. POTENTIAL 6
TO 8 FOOT SURF ALONG PORTIONS OF THE COAST. THERE IS STILL
UNCERTAINTY AS TO HOW MUCH RAIN WILL ACCUMULATE IN OUR AREA.
THERE IS A GOOD CHANCE THE REGION NORTH OF INTERSTATE 78 (NE PA
AND NW NJ) RECEIVES ONLY A TRACE OF SPRINKLES OR NO RAIN AT ALL
WHILE AMOUNTS SOMEWHERE IN SOUTHERN DELAWARE MIGHT BE QUITE
SUBSTANTIAL. HIGH TEMPERATURES WILL BE DEPENDENT ON DURATION OF
ANY RAIN DURING THE MIDDAY AND AFTN HOURS WITH WET BULBING
POSSIBLY MEANING HIGHS ONLY NEAR 70. ISOLATED THUNDER MAY OCCUR
IN DE AND COASTAL S NJ.
LATER WEDNESDAY INTO THURSDAY...A DISTINCTLY RAINFREE PERIOD AS THE
COASTAL LOW TURNS EAST OUT TO SEA AND A COLD FRONT WITH WARM AIR
ADVECTION AHEAD OF IT AND THEN EVENTUALLY A SLIVER OF INSTABILITY
ALONG IT ARRIVES FOR THURSDAY NIGHT. SO A VERY NICE WARMUP IS
ANTICIPATED FOR THURSDAY (15-16C AT 850MB) AND THIS SHOULD BE THE
WARMEST DAY OF THE WORK WEEK...MID 80S ANTICIPATED. SHOWERS AND
THUNDERSTORMS MAY OCCUR VERY LATE IN THE DAY OR AT NIGHT.
WHAT HAPPENS FRIDAY INTO EARLY SATURDAY IS HIGHLY UNCERTAIN AS
MODELS...ESPECIALLY THE ECMWF HAVE BEEN FLIP FLOPPING. IT APPEARS
THAT THERE IS A POSSIBLE STALLING OR SLOWING OF THE COLD FRONTAL
PASSAGE SO THAT SHOWERS NEED TO REMAIN IN THE FORECAST. VERY LOW
CONFIDENCE ON WHAT WILL OCCUR FOR THIS TIME FRAME OF THE FORECAST.
THE OP EC IS AT ODDS WITH THE GEFS.
LATER SATURDAY AND SUNDAY...HIGH PRESSURE IS EXPECTED TO FOLLOW THE
COLD FRONTS SEAWARD PASSAGE. IT WILL BE A TYPICAL EARLY AUTUMN AIR
MASS...SEASONABLY COOLER...WITH HIGHS MAINLY IN THE 70S AND LOWS MOSTLY
IN THE 50S.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THERE WERE NOT MANY CHANGES IN THE 06Z TAFS...COMPARED TO THE 00Z
TAFS. THE TRENDS IN THE OPERATIONAL MODELS REMAIN ABOUT THE SAME.
HIGH/MID LEVEL CLOUDINESS INCREASE OVER THE AREA...FOLLOWED BY
LOWER CLOUDS LATER THIS AFTERNOON AND TONIGHT...ESPECIALLY
SOUTH/EAST. WE HAVE VFR CONDITIONS IN THE TERMINALS EVERYWHERE
THRU 06Z TUE...WITH SOME MVFR FOR THE 30 HT PHL TAF COVERING THE
06Z-12Z TUE PERIOD. WINDS WILL INCREASE FROM THE NE/E TODAY AND
REMAIN AROUND 10 KNOTS TONIGHT. CLOSER TO THE COAST WINDS WILL BE
5 TO 10 KTS HIGHER WITH SOME GUSTINESS POSSIBLE.
OUTLOOK...
TUESDAY...VFR CIGS OCNLLY MVFR CONDITIONS IN SCATTERED SHOWERS.
BRIEF IFR CONDS POSSIBLE VCNTY KMIV AND KACY IN HEAVIER SHOWERS.
EAST TO NORTHEAST GUSTS 18-28 KT. CONFIDENCE: AVERAGE
WEDNESDAY...MAINLY VFR WITH ANY LINGERING SHOWERS TENDING TO END
FROM WEST TO EAST. CONFIDENCE: AVERAGE.
WEDNESDAY NIGHT AND THURSDAY...VFR EXCEPT FOR LATE NIGHT AND EARLY
MORNING LOW CLOUDS AND FOG. THERE IS ALSO A CHANCE OF AFTERNOON
SHOWERS AND THUNDERSTORMS WITH MVFR AND IFR CONDITIONS POSSIBLE AT
TIMES. CONFIDENCE: AVERAGE.
THURSDAY NIGHT...A CHANCE OF SHOWERS AND THUNDERSTORMS WITH MVFR AND
IFR CONDITIONS POSSIBLE AT TIMES. CONFIDENCE: AVERAGE.
FRIDAY...MAINLY VFR BUT CONFIDENCE IS WELL BELOW AVERAGE SINCE A MVFR
OR EVEN IFR CONDITION SCENARIO COULD DEVELOP IF THE PROJECTED COLD
FRONTAL PASSAGE STALLS IN OUR AREA FOR 12 HOURS.
&&
.MARINE...
WE WILL CONTINUE WITH SCA FLAGS FOR THE WATERS TODAY...WE WILL DELAY
THE ONSET TIME A FEW HOURS THAN EARLIER SET. WINDS/SEAS EXPECTED TO
SLOWLY INCREASE TODAY AND SEAS ON THE OCEAN SHOULD BUILD TO 5 TO 7
FT BY TONIGHT. SCA CONDITIONS LOOK TO PERSIST SEVERAL PERIODS.
OUTLOOK...
TUESDAY...A SMALL CRAFT ADVISORY IS IN EFFECT FOR A BRISK
EAST-NORTHEASTERLY FLOW AND SEAS ABOVE 5 FT.
TUESDAY NIGHT AND WEDNESDAY...SMALL CRAFT ADVISORY CONDITIONS ARE
EXPECTED TO CONTINUE, ESPECIALLY ON OUR OCEAN WATERS. WE DID NOT
EXTEND THE ADVISORY AT THIS TIME SINCE WE FIRST WANT TO BE SURE WE
REACH ADVISORY CONDITION TODAY.
WEDNESDAY NIGHT...WIND SPEEDS ARE FORECAST TO FALL BELOW THE
SMALL CRAFT ADVISORY CRITERION. HOWEVER, WAVES ON OUR OCEAN WATERS
MAY REMAIN AROUND 5 FEET.
THURSDAY THROUGH FRIDAY...NO MARINE HEADLINES ARE ANTICIPATED
ALTHOUGH THERE MAY BE A SHORT WINDOW OF SMALL CRAFT ADVISORY
CONDITIONS FRIDAY?
&&
.TIDES/COASTAL FLOODING...
THE ONSHORE FLOW WILL INCREASE TODAY AND REMAIN IN PLACE THE NEXT
SEVERAL DAYS. TIDAL DEPARTURES WILL INCREASE...BUT THE DEGREE OF
DEPARTURE REMAINS UNCERTAIN. THE HIGHER OF THE TOW TIDES THIS EVENING
WILL PROBABLY BE AROUND MINOR TIDAL FLOODING LEVELS...PERHAPS A BIT
OVER. WE LOOK TO FALL IN THE RANGE OF...PROBABLY NOT ENOUGH OVER FOR
STATEMENTS TO BE ISSUED...SO WE WILL GO THIS ROUTE FOR NOW. STAY
TUNED FOR UPDATES LATER TODAY.
THE EAST-NORTHEAST FLOW IS EXPECTED TO CONTINUE DURING THE SUBSEQUENT
TWO TO FOUR HIGH TIDE CYCLES FOR TUE-WED AND IT MAY CAUSE ADDITIONAL
MINOR TIDAL FLOODING IN SOME AREAS.
THE PHILADELPHIA AREA WILL REMAIN HIGHLIGHTED ON THE WWA POINT AND
CLICK MAP BUT IT IS LEAST LIKELY TO EXCEED THE MINOR COASTAL
FLOOD THRESHOLD...DUE TO THE NORTHEAST FLOW.
WAVE RUNUP ALONG THE ATLANTIC SHORES MAY ADD LOCALLY TO THE
INUNDATION IMPACT....ESPECIALLY TUESDAY.
ADDITIONALLY...BEACH EROSION MAY OCCUR.
&&
.RIP CURRENTS...
AN INCREASING NORTHEASTERLY FLOW, COMBINED WITH THE FULL MOON AND
BUILDING WAVES IN THE SURF ZONE, RESULTS IN A MODERATE RISK OF
DANGEROUS RIP CURRENTS TODAY.
A MODERATE TO STRONG NORTHEASTERLY FLOW CONTINUES TUESDAY AND
WEDNESDAY CREATING AT LEAST A MODERATE RISK FOR THE FORMATION OF
DANGEROUS RIP CURRENTS.
SURF SHOULD BUILD TO AT LEAST 5 FEET THIS AFTERNOON... 6 TO
POSSIBLY 8 FEET TUESDAY AND WEDNESDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT TUESDAY FOR ANZ431-452>455.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT TUESDAY FOR ANZ430-450-451.
&&
$$
SYNOPSIS...DRAG
NEAR TERM...NIERENBERG/O`HARA
SHORT TERM...O`HARA
LONG TERM...DRAG
AVIATION...DRAG/O`HARA
MARINE...DRAG/O`HARA
TIDES/COASTAL FLOODING...
RIP CURRENTS...
AREA FORECAST DISCUSSION
NWS JACKSON KY
1018 AM EDT MON SEP 8 2014
.UPDATE...
ISSUED AT 1018 AM EDT MON SEP 8 2014
FOR THIS MORNINGS UPDATE BROUGHT GRIDS IN LINE WITH HOURLY OBS.
STUBBORN FOG AND LOW STRATUS IS LINGERING ACROSS THE AREA THIS
MORNING...MAINLY DUE TO NORTHEAST WINDS ACROSS MUCH OF THE CWA WHICH
DO TEND TO KEEP LOW STRATUS IN PLACE. HOWEVER STILL EXPECT A GRADUAL
LIFTING AND EROSION OF THE FOG AND STRATUS ONCE EFFECTS OF SUN ARE
ABLE TO BURN THROUGH TO THE SFC. A WEAK SOUTHEASTERN DOWN SLOPE FLOW
APPEARS TO BE KEEPING THE FOG AND STRATUS AT BAY ACROSS OUR HIGHER
TERRAIN IN THE SOUTHEAST.
MID LEVEL SHORT WAVE CONTINUES TO ROLL UP INTO THE MID OHIO VALLEY
THIS MORNING. THIS FEATURE IS FAIRLY VISIBLE IN WATER VAPOR IMAGES.
WHILE CAN NOT TOTALLY RULE OUT SOME SHOWER AND THUNDERSTORM ACTIVITY
THROUGH THE DAY CONFIDENCE IS WANING CONSIDERABLY. THE RAP...AND TO A
LESSER EXTENT GFS FCST SOUNDINGS ARE SHOWING A WEAK CAP ACROSS MUCH
OF THE AREA. THIS IS SOMEWHAT IN LINE WITH ILN/OHX MORNING SOUNDINGS
THOUGH BEING GENERALLY OUTSIDE OF THE INFLUENCE OF THE SHORTWAVE
THEY MAY NOT BE A GOOD REPRESENTATION OF THE PROFILE ACROSS OUR AREA.
DISCOUNTED THE NAM/S SOUNDING AS IN TYPICAL FASHION IT GREATLY
OVERDOES BOUNDARY LAYER MOISTURE AND CONSEQUENTLY BOUNDARY LAYER
INSTABILITY AND SOUNDING PARAMETERS. THE HRRR HAS TRENDED TOWARDS A
BIT LESS COVERAGE IN ACTIVITY AS WELL...AND INITIATES A BIT LATER IN
THE DAY THAN PREVIOUS RUNS. DID DELAY DEVELOPMENT OF ACTIVITY UNTIL
LATE MORNING/EARLY AFTERNOON BUT IN GENERAL KEPT INHERITED ISOLD AND
SCT POPS FOR THE AFTERNOON TIME FRAME.
UPDATE ISSUED AT 730 AM EDT MON SEP 8 2014
TWEAKED THE GRIDS A BIT EARLY THIS MORNING TO FINE TUNE THE SKY COVER
AND T/TD PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE
NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 345 AM EDT MON SEP 8 2014
07Z SFC ANALYSIS SHOWS COOL AND DRY HIGH PRESSURE SPRAWLED OUT FROM
THE OHIO VALLEY THROUGH THE NEW ENGLAND STATES. GENERAL LOW PRESSURE
IS FOUND OVER THE DEEP SOUTH AND ALONG THE SOUTHEAST COAST. NOT FAR
FROM EAST KENTUCKY IS A STALLED FRONTAL BOUNDARY LURKING JUST TO THE
SOUTH. THIS HAS HELPED TO PREVENT THE DRY COMPONENT OF THE HIGH
PRESSURE FROM MAKING IT THROUGH ALL OF THE STATE AS DEWPOINTS ALONG
THE TENNESSEE BORDER ARE IN THE LOW AND MID 60S WHILE MID AND UPPER
50S EXIST TO THE NORTH. THESE NORTHERN SPOTS ARE ALSO ENJOYING
TEMPERATURES DOWN INTO THE MIDDLE AND UPPER 50S...PARTICULARLY IN THE
VALLEYS WHERE MOSTLY CLEAR SKIES HAVE ALLOWED FOR DECENT RADIATIONAL
COOLING BELOW THE THERMAL INVERSION. MEANWHILE...RIDGES AND LOCATIONS
TO THE SOUTH WITH HIGHER DEWPOINTS ARE SEEING TEMPERATURES A FEW
DEGREES MORE. A COUPLE LARGE PATCHES OF LOW CLOUDS ARE AFFECTING
SOUTHEAST KENTUCKY EARLY THIS MORNING HELPING TO DISRUPT THE FOG
FORMATION...THOUGH THERE WILL UNDOUBTEDLY BE PATCHY FOG...LOCALLY
DENSE...IN MANY VALLEY LOCATIONS GENERALLY CORRESPONDING TO THE
CLEAR SPOTS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH ANOTHER POCKET OF ENERGY
ROLLING EAST THROUGH GENERALLY FLAT FLOW TODAY...HELPING TO LOWER
HEIGHTS LOCALLY AND BRING SOME EXTRA LIFT TO THE AREA. THIS MOVES
THROUGH BY EVENING WITH CONTINUED RELATIVELY FAST AND NEARLY ZONAL
FLOW INTO THE DAY TUESDAY. LATE IN THE SHORT TERM PORTION OF THE
FORECAST HEIGHTS WILL CLIMB A NOTCH AHEAD OF A LARGE AND DEEPENING
TROUGH OVER THE ROCKY MOUNTAIN AND HIGH PLAINS STATES. WITH THE MODEL
SIMILARITIES HAVE GONE MAINLY WITH A BLEND OF THE HRRR AND NAM12 FOR
WX SPECIFICS DURING THE FIRST 12-18 HOURS AND THEN THE 00Z
ECMWF/NAM12 THROUGH TUESDAY.
SENSIBLE WEATHER WILL FEATURE A CONTINUED COOL AND DRY DAY ACROSS THE
FAR NORTHWEST PARTS OF THE AREA WHILE TO THE SOUTHEAST THERE WILL BE
MUCH MORE CLOUD COVER ALONG WITH A THREAT FOR SHOWERS THROUGH
THE MORNING. BY MIDDAY THUNDER CHANCES WILL PICK UP OWING TO BUILDING
INSTABILITY AND THE NEARBY FRONT BEING ACTED UPON BY THE PASSING MID
LEVEL SHORT WAVE. THE PCPN THREAT AND SOME OF THE CLOUD COVER WILL
RETREAT TO THE EAST LATER TONIGHT WITH ANOTHER NIGHT OF MINOR RIDGE
TO VALLEY TEMPERATURE DIFFERENCES AMIDST A NW TO SE STRIATION IN
DEWPOINTS. DUE TO THIS ANTICIPATE PATCHY VALLEY FOG AFTER MIDNIGHT
FOR MOST LOCATIONS...PARTICULARLY ONES THAT MANAGE TO SEE ANY RAIN
DURING THE DAY AND EVENING. TUESDAY WILL BE QUIET AND DRY...BUT A TAD
WARMER WHILE THE DEVELOPING LOW TO THE EAST STARTS TO LIFT NORTH
ALONG THE SOUTH EAST ATLANTIC SEABOARD.
STARTED WITH THE CONSSHORT FOR T...TD...AND WINDS...THROUGH THE
FIRST 24 HOURS FOLLOWED BY THE SUPERBLEND UNTIL 00Z WED. PER
USUAL...MADE MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS
TONIGHT. AS FOR POPS...ENDED UP CLOSER TO THE LOWER MAV GUIDANCE
TODAY AND SIMILAR TO A BLEND OF THE RATHER LOW NUMBERS THEREAFTER
THROUGH THE REMAINDER OF THE SHORT TERM FORECAST.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM EDT MON SEP 8 2014
THE MODELS REMAIN IN GOOD AGREEMENT IN THE LONG TERM...WITH A LARGE
RIDGE OF HIGH PRESSURE ALOFT INFLUENCING THE WEATHER OF EASTERN
KENTUCKY TO BEGIN THE PERIOD. DRY WEATHER SHOULD BE ON TAP TUESDAY
NIGHT INTO EARLY WEDNESDAY AFTERNOON AS HIGH PRESSURE REMAINS IN
CONTROL. HOWEVER...THIS UPPER RIDGE WILL BE DISPLACED AS DEEP AREA
OF LOW PRESSURE...BOTH ALOFT AND AT THE SURFACE...COMES TOGETHER
OVER THE NORTHERN PLAINS AND BEGINS TO PUSH ACROSS THE NORTHERN
MISSISSIPPI VALLEY ON WEDNESDAY. THE SURFACE COLD FRONT ASSOCIATED
WITH THIS POTENT SYSTEM WILL BRING UNSETTLED WEATHER TO THE AREA
WEDNESDAY NIGHT AND THURSDAY. THE PRIMARY CONCERN WITH THIS WEATHER
SYSTEM WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. THE MODELS
HAVE THE FRONT SLOWING DOWN AND NEARLY STALLING ACROSS OUR AREA ON
THURSDAY. SHOWERS AND STORMS ARE EXPECTED TO FIRE ALL ALONG THE
BOUNDARY AS LARGE AMOUNTS OF WARM MOIST AIR OFF THE GULF OF MEXICO
IS CARRIED NORTHWARD INTO THE BOUNDARY ON SOUTHERLY WINDS. THE BEST
CHANCE FOR RAIN LOOKS TO BE FROM LATE THURSDAY MORNING THROUGH LATE
THURSDAY AFTERNOON WHEN MOISTURE FLOW INTO THE FRONTAL ZONE IS AT
ITS PEAK. THERE WILL ALSO BE THE POTENTIAL FOR A FEW STRONG
THUNDERSTORMS ON THURSDAY AS THE FRONT MOVES THROUGH AS THERE WILL
BE STRONG DYNAMICS ASSOCIATED WITH THE BOUNDARY AND ITS PARENT UPPER
LEVEL SYSTEM. THUNDERSTORMS SHOULD THEN GIVE WAY TO RAIN SHOWER
BEHIND THE FRONT THURSDAY NIGHT AS THE COOLER AIR MOVES IN BEHIND
THE FRONT. THE FRONT IS EXPECTED TO EVENTUALLY CLEAR THE AREA LATE
THURSDAY NIGHT INTO EARLY FRIDAY MORNING...AS A LARGE RIDGE OF
CANADIAN HIGH PRESSURE PUSHES IT OFF TO OUR EAST. THIS AREA OF HIGH
PRESSURE WILL BRING A SIGNIFICANT PATTERN CHANGE TO THE MAJORITY OF
THE CONUS EAST OF THE ROCKY MOUNTAINS FROM FRIDAY ONWARD.
AFTER SLIGHTLY ABOVE NORMAL TEMPERATURES TUESDAY NIGHT AND
WEDNESDAY...A PERIOD OF UNSEASONABLE COOLING WILL BE OCCURRING.
HIGHS ON WEDNESDAY ARE EXPECTED TO TOP OUT IN THE MID TO UPPER 80S
AS SOUTHERLY WINDS BRING WARM MOIST AIR FROM THE GULF OF MEXICO INTO
THE REGION. ONCE THE FRONT ARRIVES ON THURSDAY...WIDESPREAD CLOUD
COVER AND PRECIPITATION WILL KEEP TEMPERATURES WELL BELOW
NORMAL...WITH HIGHS ONLY CLIMBING TO AROUND 80 BY THURSDAY
AFTERNOON. ONCE THE BOUNDARY HAS CLEARED THE AREA LATE THURSDAY
NIGHT...AN INVASION OF COOL AN DRY CANADIAN AIR WILL BEGIN TO OCCUR.
WITH WINDS SHIFTING TO THE NORTH BEHIND THE FRONT...TEMPERATURES
WILL BE HARD PRESSED TO CLIMB INTO THE MID 70S ON FRIDAY. THE COOL
WEATHER WILL THEN PERSIST THROUGH THE WEEKEND AS THE RIDGE OF HIGH
PRESSURE BECOMES MORE FIRMLY ESTABLISHED. HIGH TEMPERATURES ON
SATURDAY ARE EXPECTED TO ONLY CLIMB TO AROUND 70 WITH HIGHS ON
SUNDAY ONLY WARMING INTO THE LOW 70S. OVERNIGHT LOWS IN THE 50S ARE
EXPECTED AREA WIDE FRIDAY AND SATURDAY NIGHT AS THE COOL CANADIAN
AIR POURS INTO THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 750 AM EDT MON SEP 8 2014
A LOW CLOUD DECK REMAINS IN PLACE OVER MUCH OF EAST KENTUCKY WITH
STILL SOME WESTWARD EXPANSION NOTED IN THE SATELLITE TRENDS. THESE
CLOUDS ARE GENERALLY IN THE MVFR RANGE FOR CIGS...BUT THERE ARE AREAS
OF MUCH LOWER CIGS DOWN TO LIFR IN THE SOUTH ALONG WITH LOW VIS FROM
FOG. ISOLATED TO SCATTERED RAIN SHOWERS ARE EXPECTED TO REDEVELOP...
MAINLY EAST OF JKL...BY MID MORNING AND PERSISTING INTO THE AFTERNOON.
AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT AS WELL THROUGH THE
EARLY EVENING HOURS. HAVE A VCTS FOR THIS IN THE ALL THE TAFS EXCEPT
SYM. WINDS THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE ACROSS THE
FORECAST AREA.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
750 AM EDT MON SEP 8 2014
.UPDATE...
ISSUED AT 730 AM EDT MON SEP 8 2014
TWEAKED THE GRIDS A BIT EARLY THIS MORNING TO FINE TUNE THE SKY COVER
AND T/TD PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE
NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 345 AM EDT MON SEP 8 2014
07Z SFC ANALYSIS SHOWS COOL AND DRY HIGH PRESSURE SPRAWLED OUT FROM
THE OHIO VALLEY THROUGH THE NEW ENGLAND STATES. GENERAL LOW PRESSURE
IS FOUND OVER THE DEEP SOUTH AND ALONG THE SOUTHEAST COAST. NOT FAR
FROM EAST KENTUCKY IS A STALLED FRONTAL BOUNDARY LURKING JUST TO THE
SOUTH. THIS HAS HELPED TO PREVENT THE DRY COMPONENT OF THE HIGH
PRESSURE FROM MAKING IT THROUGH ALL OF THE STATE AS DEWPOINTS ALONG
THE TENNESSEE BORDER ARE IN THE LOW AND MID 60S WHILE MID AND UPPER
50S EXIST TO THE NORTH. THESE NORTHERN SPOTS ARE ALSO ENJOYING
TEMPERATURES DOWN INTO THE MIDDLE AND UPPER 50S...PARTICULARLY IN THE
VALLEYS WHERE MOSTLY CLEAR SKIES HAVE ALLOWED FOR DECENT RADIATIONAL
COOLING BELOW THE THERMAL INVERSION. MEANWHILE...RIDGES AND LOCATIONS
TO THE SOUTH WITH HIGHER DEWPOINTS ARE SEEING TEMPERATURES A FEW
DEGREES MORE. A COUPLE LARGE PATCHES OF LOW CLOUDS ARE AFFECTING
SOUTHEAST KENTUCKY EARLY THIS MORNING HELPING TO DISRUPT THE FOG
FORMATION...THOUGH THERE WILL UNDOUBTEDLY BE PATCHY FOG...LOCALLY
DENSE...IN MANY VALLEY LOCATIONS GENERALLY CORRESPONDING TO THE
CLEAR SPOTS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH ANOTHER POCKET OF ENERGY
ROLLING EAST THROUGH GENERALLY FLAT FLOW TODAY...HELPING TO LOWER
HEIGHTS LOCALLY AND BRING SOME EXTRA LIFT TO THE AREA. THIS MOVES
THROUGH BY EVENING WITH CONTINUED RELATIVELY FAST AND NEARLY ZONAL
FLOW INTO THE DAY TUESDAY. LATE IN THE SHORT TERM PORTION OF THE
FORECAST HEIGHTS WILL CLIMB A NOTCH AHEAD OF A LARGE AND DEEPENING
TROUGH OVER THE ROCKY MOUNTAIN AND HIGH PLAINS STATES. WITH THE MODEL
SIMILARITIES HAVE GONE MAINLY WITH A BLEND OF THE HRRR AND NAM12 FOR
WX SPECIFICS DURING THE FIRST 12-18 HOURS AND THEN THE 00Z
ECMWF/NAM12 THROUGH TUESDAY.
SENSIBLE WEATHER WILL FEATURE A CONTINUED COOL AND DRY DAY ACROSS THE
FAR NORTHWEST PARTS OF THE AREA WHILE TO THE SOUTHEAST THERE WILL BE
MUCH MORE CLOUD COVER ALONG WITH A THREAT FOR SHOWERS THROUGH
THE MORNING. BY MIDDAY THUNDER CHANCES WILL PICK UP OWING TO BUILDING
INSTABILITY AND THE NEARBY FRONT BEING ACTED UPON BY THE PASSING MID
LEVEL SHORT WAVE. THE PCPN THREAT AND SOME OF THE CLOUD COVER WILL
RETREAT TO THE EAST LATER TONIGHT WITH ANOTHER NIGHT OF MINOR RIDGE
TO VALLEY TEMPERATURE DIFFERENCES AMIDST A NW TO SE STRIATION IN
DEWPOINTS. DUE TO THIS ANTICIPATE PATCHY VALLEY FOG AFTER MIDNIGHT
FOR MOST LOCATIONS...PARTICULARLY ONES THAT MANAGE TO SEE ANY RAIN
DURING THE DAY AND EVENING. TUESDAY WILL BE QUIET AND DRY...BUT A TAD
WARMER WHILE THE DEVELOPING LOW TO THE EAST STARTS TO LIFT NORTH
ALONG THE SOUTH EAST ATLANTIC SEABOARD.
STARTED WITH THE CONSSHORT FOR T...TD...AND WINDS...THROUGH THE
FIRST 24 HOURS FOLLOWED BY THE SUPERBLEND UNTIL 00Z WED. PER
USUAL...MADE MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS
TONIGHT. AS FOR POPS...ENDED UP CLOSER TO THE LOWER MAV GUIDANCE
TODAY AND SIMILAR TO A BLEND OF THE RATHER LOW NUMBERS THEREAFTER
THROUGH THE REMAINDER OF THE SHORT TERM FORECAST.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM EDT MON SEP 8 2014
THE MODELS REMAIN IN GOOD AGREEMENT IN THE LONG TERM...WITH A LARGE
RIDGE OF HIGH PRESSURE ALOFT INFLUENCING THE WEATHER OF EASTERN
KENTUCKY TO BEGIN THE PERIOD. DRY WEATHER SHOULD BE ON TAP TUESDAY
NIGHT INTO EARLY WEDNESDAY AFTERNOON AS HIGH PRESSURE REMAINS IN
CONTROL. HOWEVER...THIS UPPER RIDGE WILL BE DISPLACED AS DEEP AREA
OF LOW PRESSURE...BOTH ALOFT AND AT THE SURFACE...COMES TOGETHER
OVER THE NORTHERN PLAINS AND BEGINS TO PUSH ACROSS THE NORTHERN
MISSISSIPPI VALLEY ON WEDNESDAY. THE SURFACE COLD FRONT ASSOCIATED
WITH THIS POTENT SYSTEM WILL BRING UNSETTLED WEATHER TO THE AREA
WEDNESDAY NIGHT AND THURSDAY. THE PRIMARY CONCERN WITH THIS WEATHER
SYSTEM WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. THE MODELS
HAVE THE FRONT SLOWING DOWN AND NEARLY STALLING ACROSS OUR AREA ON
THURSDAY. SHOWERS AND STORMS ARE EXPECTED TO FIRE ALL ALONG THE
BOUNDARY AS LARGE AMOUNTS OF WARM MOIST AIR OFF THE GULF OF MEXICO
IS CARRIED NORTHWARD INTO THE BOUNDARY ON SOUTHERLY WINDS. THE BEST
CHANCE FOR RAIN LOOKS TO BE FROM LATE THURSDAY MORNING THROUGH LATE
THURSDAY AFTERNOON WHEN MOISTURE FLOW INTO THE FRONTAL ZONE IS AT
ITS PEAK. THERE WILL ALSO BE THE POTENTIAL FOR A FEW STRONG
THUNDERSTORMS ON THURSDAY AS THE FRONT MOVES THROUGH AS THERE WILL
BE STRONG DYNAMICS ASSOCIATED WITH THE BOUNDARY AND ITS PARENT UPPER
LEVEL SYSTEM. THUNDERSTORMS SHOULD THEN GIVE WAY TO RAIN SHOWER
BEHIND THE FRONT THURSDAY NIGHT AS THE COOLER AIR MOVES IN BEHIND
THE FRONT. THE FRONT IS EXPECTED TO EVENTUALLY CLEAR THE AREA LATE
THURSDAY NIGHT INTO EARLY FRIDAY MORNING...AS A LARGE RIDGE OF
CANADIAN HIGH PRESSURE PUSHES IT OFF TO OUR EAST. THIS AREA OF HIGH
PRESSURE WILL BRING A SIGNIFICANT PATTERN CHANGE TO THE MAJORITY OF
THE CONUS EAST OF THE ROCKY MOUNTAINS FROM FRIDAY ONWARD.
AFTER SLIGHTLY ABOVE NORMAL TEMPERATURES TUESDAY NIGHT AND
WEDNESDAY...A PERIOD OF UNSEASONABLE COOLING WILL BE OCCURRING.
HIGHS ON WEDNESDAY ARE EXPECTED TO TOP OUT IN THE MID TO UPPER 80S
AS SOUTHERLY WINDS BRING WARM MOIST AIR FROM THE GULF OF MEXICO INTO
THE REGION. ONCE THE FRONT ARRIVES ON THURSDAY...WIDESPREAD CLOUD
COVER AND PRECIPITATION WILL KEEP TEMPERATURES WELL BELOW
NORMAL...WITH HIGHS ONLY CLIMBING TO AROUND 80 BY THURSDAY
AFTERNOON. ONCE THE BOUNDARY HAS CLEARED THE AREA LATE THURSDAY
NIGHT...AN INVASION OF COOL AN DRY CANADIAN AIR WILL BEGIN TO OCCUR.
WITH WINDS SHIFTING TO THE NORTH BEHIND THE FRONT...TEMPERATURES
WILL BE HARD PRESSED TO CLIMB INTO THE MID 70S ON FRIDAY. THE COOL
WEATHER WILL THEN PERSIST THROUGH THE WEEKEND AS THE RIDGE OF HIGH
PRESSURE BECOMES MORE FIRMLY ESTABLISHED. HIGH TEMPERATURES ON
SATURDAY ARE EXPECTED TO ONLY CLIMB TO AROUND 70 WITH HIGHS ON
SUNDAY ONLY WARMING INTO THE LOW 70S. OVERNIGHT LOWS IN THE 50S ARE
EXPECTED AREA WIDE FRIDAY AND SATURDAY NIGHT AS THE COOL CANADIAN
AIR POURS INTO THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 750 AM EDT MON SEP 8 2014
A LOW CLOUD DECK REMAINS IN PLACE OVER MUCH OF EAST KENTUCKY WITH
STILL SOME WESTWARD EXPANSION NOTED IN THE SATELLITE TRENDS. THESE
CLOUDS ARE GENERALLY IN THE MVFR RANGE FOR CIGS...BUT THERE ARE AREAS
OF MUCH LOWER CIGS DOWN TO LIFR IN THE SOUTH ALONG WITH LOW VIS FROM
FOG. ISOLATED TO SCATTERED RAIN SHOWERS ARE EXPECTED TO REDEVELOP...
MAINLY EAST OF JKL...BY MID MORNING AND PERSISTING INTO THE AFTERNOON.
AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT AS WELL THROUGH THE
EARLY EVENING HOURS. HAVE A VCTS FOR THIS IN THE ALL THE TAFS EXCEPT
SYM. WINDS THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE ACROSS THE
FORECAST AREA.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
730 AM EDT MON SEP 8 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM EDT MON SEP 8 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT ZONAL FLOW
ALF ALONG THE CNDN BORDER. A SHRTWV RDG EMBEDDED IN THIS W-E FLOW IS
MOVING THRU THE UPR LKS EARLY THIS MRNG...SUPPORTING SFC HI PRES
OVER THE SE GREAT LKS. ACYC SW FLOW ARND THIS HI AND DRY AIRMASS
SHOWN ON LOCAL 00Z RAOBS...ESPECIALLY AT MPX WHERE THE 00Z PWAT IS
0.48 INCH OR 60 PCT OF NORMAL...ARE RESULTING IN MOCLR CONDITIONS
ACRS UPR MI. BUT HI CLDS ARE APRCHG WRN UPR MI IN ADVANCE OF A
SHRTWV MOVING E THRU THE NRN PLAINS IN THE SRN BRANCH FLOW. ANOTHER
SHRTWV WITHIN THE STRONGER NRN BRANCH IS PUSHING EWD THRU SRN
SASKATCHEWAN.
MAIN FCST CONCERNS IN THE SHORT TERM WL BE WHETHER AND IF THEN HOW
QUICKLY SHOWERS SPREAD INTO UPR MI IN ADVANCE OF UPSTREAM SHRTWVS.
TODAY...SRN BRANCH DISTURBANCE IN THE NRN PLAINS EARLY THIS MRNG IS
PROGGED TO MOVE E AND INTO NRN WI BY 00Z TUE. ALTHOUGH UPR MI WL BE
ON THE FAVORED CYC SIDE OF THE TRACK OF THIS DISTURBANCE...
PERSISTENT SW FLOW ARND SFC HI PRES MOVING INTO NEW ENGLAND WL
ADVECT DRIER AIR FM THE SW AND THE DIRECTION OF MPX. SO ALTHOUGH
PVA/H5-3 QVECTOR CNVGC AHEAD OF THE SHRTWV IS FCST TO IMPACT MAINLY
THE S HALF OF UPR MI...MODELS INDICATE AN ABSENCE OF ANY SGNFT H85-5
QVECTOR CNVGC. THIS SETUP SUGGESTS THE MAIN IMPACT WL BE THE HI CLDS
SPILLING E FM MN. SO EVEN THOUGH SOME MODELS GENERATE PCPN NEAR THE
WI BORDER AFTER 18Z...OPTED TO MAINTAIN GOING DRY FCST. FCST H85
TEMPS RANGING FM ABOUT 11C OVER THE E TO 13C OVER THE W AND MIXING
TO H8-85 AS OBSVD UPSTREAM YDAY SUPPORTS HI TEMPS IN THE MID/UPR
70S. SSW FLOW OFF LK MI WL BRING COOLER WX TO THE ERN CWA. THE
DAYTIME HEATING/MIXING AND H925 WINDS IN THE 20-30KT RANGE WL RESULT
IN GUSTY WINDS BY LATE MRNG. GIVEN THE FVRBL CONDITIONS FOR GUSTY
WINDS...BUMPED UP FCST GUSTS A COUPLE OF KTS ABV WIND GUST PROCEDURE
OUTPUT.
TNGT...UPR MI IS FCST TO BE DOMINATED BY DEEP LYR QVECTOR DVGC BTWN
DEPARTING SRN BRANCH SHRTWV THRU NRN LOWER MI AND NRN BRANCH
DISTURBANCE CROSSING NW ONTARIO. SO ALTHOUGH THE PERSISTENT SW FLOW
BTWN THE HI PRES MOVING INTO THE CNDN MARITIMES AND AN APRCHG COLD
FNT ATTENDANT TO THE NRN BRANCH SHRTWV WL BRING A RETURN OF HIER H85
THETA E INTO THE UPR LKS...LINGERING MID LVL DRY AIR BEST SHOWN BY
THE 00Z GFS FCST SDNGS WARRANTS KEEPING THE GOING DRY FCST. STEADY
SW WIND AND INCRSG LLVL MSTR THAT MAY RESULT IN SOME SC ESPECIALLY
OVER THE W HALF CLOSER TO THE HIER H85 THETA E WL RESULT IN WELL ABV
NORMAL MIN TEMPS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 441 AM EDT MON SEP 8 2014
THE MAIN THREATS THIS PERIOD WILL BE THE HEAVY RAIN TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT...STRONG NORTHERLY WINDS LATE WEDNESDAY
AFTERNOON THROUGH WEDNESDAY NIGHT ALONG LAKE SUPERIOR...AND A
PROLONGED PERIOD OF COOL WEATHER STARTING THURSDAY WITH NEAR OR
BELOW FREEZING TEMPERATURES ANTICIPATED LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING /COOLEST INLAND FROM THE GREAT LAKES/.
TUESDAY...
THE LAST DAY OF ABOVE NORMAL TEMPERATURES...OR EVEN NEAR NORMAL
TEMPERATURES FOR THE NEXT WEEK WILL BE TUESDAY. FAVORABLE S WINDS
OVER THE E HALF OF UPPER MI SHOULD ALLOW AREAS NEAR LAKE SUPERIOR TO
RISE INTO THE MID TO UPPER 70S...WITH LOW 70S COMMON ELSEWHERE. LOOK
FOR A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS OVER THE
W HALF OF THE CWA AS THE SFC TROUGH CONNECTING LOWS OVER CENTRAL
PLAINS AND HUDSON BAY SHIFTS ACROSS THE CWA. BROAD W TO SW FLOW
ALOFT WILL KEEP SWINGING DISTURBANCES ACROSS THE AREA AT 500MB.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...
MODELS ARE COMING INTO BETTER AGREEMENT FOR THE TRACK OF THE SFC LOW
EJECTING NE OUT OF THE CENTRAL PLAINS TUESDAY NIGHT. LOOK FOR THE
SFC LOW TO BE SET UP ACROSS S MN AND IA AT 06Z TO SHIFT OVER S
CENTRAL UPPER MI/NE WI/N LAKE MI BY MID AFTERNOON. THIS WILL BRING
WIDESPREAD RAIN TO THE REGION. WITH PW VALUES RISING TO 1.5-2IN
HEAVY RAIN IS A CONCERN. CURRENTLY HAVE 1.5 TO JUST OVER 2IN OF RAIN
FCST FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. KEPT THE SMALL
CHANCE OF THUNDERSTORMS ALONG LAKE MI WEDNESDAY. WITH THE TRACK OF
THE SFC LOW...AND STRONG HIGH PRESSURE SET UP OVER CENTRAL AND S
ALBERTA/SASKATCHEWAN...STRONG N WINDS OF 40-45MPH WILL BE POSSIBLE
LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...WITH THE
STRONGEST WINDS MOSTLY LIKELY ACROSS THE KEWEENAW PENINSULA. A WIND
ADVISORY MAY BE NEEDED FOR THE KEWEENAW PENINSULA. AS PREVIOUSLY
NOTED...EVEN IF WINDS DON/T QUITE REACH ADVISORY CRITERIA...TREES
COULD BE MORE SUSCEPTIBLE TO FALLING DUE TO THE SATURATED GROUND AND
PLENTY OF LEAVES ON THE TREES.
WEDNESDAY NIGHT THROUGH SUNDAY...
THE SFC LOW WILL SHIFT OVER ONTARIO AND QUEBEC WEDNESDAY
NIGHT...WITH THE SFC TROUGH LINGERING ACROSS UPPER MI INTO THURSDAY.
NW FLOW WILL BRING IN PLENTY OF COLD AIR BEHIND THE LOW...WITH
TEMPERATURES REMAINING WELL BELOW NORMAL THROUGH AT LEAST THE
UPCOMING WEEKEND. 850MB TEMPS OF -1C BY 18Z THURSDAY WILL RESULT IN
LAKE EFFECT RAIN WHICH WILL LINGER THROUGH FRIDAY AS A SECOND WAVE
AND TROUGH AXIS MORE ACROSS THE CWA THURSDAY NIGHT-FRIDAY.
HAVE ADDED THE POTENTIAL FOR NEAR OR BELOW FREEZING TEMPS INLAND
FROM THE GREAT LAKES...AND PRIMARILY OVER THE W HALF OF UPPER MI
LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING AS THE LARGE AREA OF
HIGH PRESSURE TO THE W BUILDS OVERHEAD WITH DECREASING CLOUDS. WINDS
WILL BECOME MORE W OR OUT OF THE S ON SATURDAY...EFFECTIVELY ENDING
OUR LAKE EFFECT CLOUDS OR SHOWERS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 729 AM EDT MON SEP 8 2014
EXPECT VFR CONDITIONS THIS FCST PERIOD WITH STRONG SSW FLOW TAPPING
RELATIVELY DRY AIR SHOWN ON THE 00Z MPX RAOB. DAYTIME HEATING/MIXING
WL ALLOW FOR GUSTY WINDS TO 20-25 KT THIS AFTN BEFORE DECOUPLING
THIS EVNG CAUSES SOME MARGINAL LLWS BEFORE THE LLJ WEAKENS AFTER 06Z.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 AM EDT MON SEP 8 2014
FOG MAY CONTINUE TO BE A CONCERN INITIALLY OVER PORTIONS OF W AND
CENTRAL LAKE SUPERIOR. LAKE SUPERIOR WILL INITIALLY BE STUCK BETWEEN
EXITING HIGH PRESSURE OVER THE NEW ENGLAND STATES...AND A NEARING
TROUGH STRETCHING FROM NORTH DAKOTA THROUGH NORTHERN ONTARIO. LOOK
FOR THE TROUGH TO PUSH INTO LAKE SUPERIOR ON TUESDAY...WHILE A
STRONGER LOW ORGANIZES ACROSS THE CENTRAL PLAINS. EXPECT THE
DEEPENING LOW TO SHIFT NE ACROSS WI ON WEDNESDAY...AND ACROSS E
UPPER MI AND N LOWER MI LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING...BEFORE CONTINUING NE INTO QUEBEC ON THURSDAY. A PERIOD OF
N GALES WILL BE POSSIBLE LATE TUESDAY NIGHT INTO EARLY THURSDAY. IN
LARGE HIGH PRESSURE OVER S ALBERTA AND SASKATCHEWAN THURSDAY IS
EXPECTED TO DIVE ACROSS THE N AND CENTRAL PLAINS...WHILE BUILDING A
RIDGE ACROSS LAKE SUPERIOR ON THURSDAY NIGHT AND FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KF
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
701 AM CDT MON SEP 8 2014
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 255 AM CDT MON SEP 8 2014
HOW FAR SOUTH INTO THE FA WILL MORNING CONVECTION MAKE IT AND
THEN HOW QUICKLY WILL CONVECTION DEVELOP ON TUESDAY MAIN FORECAST
FOCUS IN THE SHORT TERM...ALTHOUGH SEVERE WEATHER AND HEAVY RAIN
REMAIN IN THE PICTURE FOR LATE TUESDAY.
A MERGING THUNDERSTORM CLUSTER WAS WORKING TOWARD NERN NEBR AS OF
8Z BUT ALSO MOVING INTO MLCAPE VALUE AREAS THAT WERE LESS THAN
500 J/KG PER SPC MESO PAGE. THUS WOULD SUSPECT SOME WEAKENING ON
SE EDGE THIS MORNING WHICH WAS HINTED AT BY 05Z HRRR AND RAP WHICH
KEPT MOST OF THE PRECIP IN FAR NE ZONES OR EVEN NE OF THERE...AS
DID 00Z ECMWF. HOWEVER...THAT SAID CONVECTION WAS MAINTAINING ITS
STRENGTH ENOUGH TO DISCOUNT SHORT TERM MODELS TO SOME DEGREE AND
TO INCREASE POPS IN NERN ZONES THIS MORNING AND KEEP MENTION OF
THEM PER PREV FORECAST IN THE AFTN ALONG E OF MO RIVER. DON/T KNOW
IF IT WILL HOLD TOGETHER AND ROLL DOWN MO RIVER TO OMAHA...BUT
CAN/T RULE THAT OUT ATTM. ALSO SOME HINT BY NAM AND 4KM WRF THAT
SOME NEW DEVELOPMENT COULD OCCUR ON SW SIDE THIS MORNING AND THUS
LEFT IN SMALL POPS FARTHER SW THAN RAP/HRRR WOULD SUGGEST. STILL
COUNTING ON DEBRIS BEING MINIMAL ENOUGH THIS AFTN TO ALLOW MAX
TEMPS TO REACH 80 OR BETTER ALL BUT PERHAPS FAR NERN ZONES.
ALTHOUGH SOME SMALL POPS WERE MAINTAINED TONIGHT...STILL APPEARED
THAT MAIN CONVECTIVE AREAS WOULD EITHER BE TO OUR EAST ON NOSE OF
H85 THETAE RIDGE/JET OR TO OUR WEST AS UPPER TROUGH AND MID LEVEL
MOISTURE APPROACH. THIS MOISTURE...WITH H7 DWPTS FORECAST AT 8-10
DEG C PER NAM/GFS...COULD ALLOW CONVECTION TO START OR INCREASE
FAIRLY EARLY TUESDAY AFTN AND LEAD TO LOCALLY HEAVY RAIN BY
EVENING AS PWATS WILL BE HIGH AND TRAINING OF CELLS PROBABLE.
HOWEVER...A LOT COULD/WILL DEPEND ON INITIAL DEVELOPMENT AND
RESULTANT OUTFLOW OR DIFFERENTIAL HEATING AREAS AND WILL REFRAIN
FROM BLANKET HEAVY RAIN MENTION JUST YET. WITH GENERAL MODEL
CONSENSUS THAT SRN ZONES WOULD BE LAST TO GET WIDESPREAD
CONVECTIVE OVERTURNING...MAX TEMPS IN MID/UPPER 80S ARE POSSIBLE
THERE. ALTHOUGH TEMPS SHOULD BE COOLER FARTHER NORTH...REFRAINED
FROM LOWERING JUST YET AS MORE OF THE WIDESPREAD CONVECTION MAY
HOLD OFF TILL AFTN. POTENTIAL FOR SVR WEATHER ALSO CONTINUES
ESPECIALLY WITH NAM FORECAST HODOGRAPHS FAVORABLY CURVED AHEAD OF
PREFRONTAL TROUGH/COLD FRONT FM OMAHA SWD. LIKE WHERE HEAVIER RAIN
EVENTUALLY SETS UP...SEVERE WEATHER...MAINLY ANY TORNADO
POTENTIAL...TOO WILL BE INFLUENCED BY EARLIER DAY CONVECTION BUT
MENTION OF BOTH SVR+HEAVY RAIN WILL CONTINUE IN THE HWO.
STRONGER CONVECTION COULD LINGER WELL INTO TUESDAY EVENING AND
EVEN EARLY OVERNIGHT HOURS AS LOW LEVEL JET DOESN/T SHIFT SE OF
THE AREA TIL AFTER 06Z PER MODELS...ALTHOUGH STRONGEST AND HEAVY
RAIN THREAT BY MID EVENING SHOULD SHIFT MOSTLY TO SRN AND ERN
ZONES.
ALTHOUGH H85 COOLING WILL LAG DUE TO UPPER FLOW...LOWER LEVEL
COOL/DRY ADVECTION WAS FAIRLY DECENT AND WITH PLENTY OF LOW
CLOUDS LIKELY ON WEDNESDAY...ANY HEATING/RECOVERY WILL BE LIMITED.
GENERALLY TRIMMED BACK BOTH LOWS AND HIGHS. ALTHOUGH A GENERAL
TROUGHING CONTINUED ALOFT...FORCING WAS WEAK PER QG FORECAST FM
GFS AND NAM BY AFTN. SO ALTHOUGH SMALL POPS WERE LEFT IN FOR THE
MORNING WITH A DRY AFTN...MUCH OF ANY PRECIP SHOULD BE PRETTY
LIGHT OR POSSIBLY JUST DRIZZLE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 255 AM CDT MON SEP 8 2014
EXTENDED BEGINS QUITE COOL AS H85 TEMPS LOWER INTO LOW SINGLE
DIGITS THU AND EVEN DROP BELOW ZERO THU NIGHT AS REINFORCING UPPER
SHORTWAVE SENDS EVEN COLDER AIR ACROSS THE FA. THIS WAVE COULD
ALSO SPREAD LIGHT SHOWERS ACROSS THE AREA THU MAKING IT EVEN LESS
LIKELY TO MIX TO H85. THIS IN TURN COULD BRING EVEN COLDER MAX
TEMPS TO THE REGION THAN THIS FORECAST WILL CONTAIN...WHICH WERE
ALREADY NEAR OR BELOW COLDEST MAX TEMPS ON RECORD FOR SEPT 11 OF
58 IN LINCOLN...56 IN OMAHA AND 55 AT NORFOLK.
IF SKIES CLEAR QUICKLY ENOUGH THURSDAY LOWS COULD BE A CATEGORY
COOLER THAN THE GENERALLY 40-45 GOING BY FRIDAY MORNING AND WITH
SURFACE STILL IN VICINITY SAT MORNING MORE 30S COULD BE NEEDED IN
FUTURE FORECASTS THAT DAY AS WELL. OTHERWISE 00Z ECMWF INDICATED
TEMPERATURES SHOULD MODERATE NEXT WEEKEND ALONG WITH PRECIP
HOLDING OFF TILL NEXT WAVE SUN NIGHT. GFS WAS A LITTLE COOLER AND
SUGGESTIVE OF LIGHT PRECIP SAT AS UPPER TROUGH TO BEGIN WEEKEND
WAS A TOUCH MORE AMPLIFIED. FORECAST FOR NEXT SATURDAY AND SUNDAY
WAS KEPT DRY FOR NOW.
&&
.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 655 AM CDT MON SEP 8 2014
PRIMARY AREA OF CONVECTION IS EXPECTED TO REMAIN NORTH AND EAST OF
TAF SITES THROUGH 18Z. MID LEVEL VFR CIGS LIKELY DURING THIS TIME
AT BOTH KOFK AND KOMA. VFR CONDITIONS SHOULD PREVAIL THROUGH THE
PERIOD. SOME CHANCE OF MORE STORMS MOVING IN FROM THE SOUTH AFTER
06Z ESPECIALLY AT KLNK AS NEXT POCKET OF INSTABILITY LIFTS NORTH
WITH THE WARM FRONT. NO MENTION AT THIS TIME DUE TO UNCERTAINTY
SO LATE IN THE PERIOD.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...CHERMOK
LONG TERM...CHERMOK
AVIATION...FOBERT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
911 AM CDT MON SEP 8 2014
.UPDATE...
ISSUED AT 911 AM CDT MON SEP 8 2014
A COLD FRONT CONTINUES TO PROGRESS THROUGH NORTHWEST NORTH DAKOTA
FASTER THAN PREVIOUSLY ANTICIPATED. FURTHERMORE...TRAILING STRATUS
IS QUITE A BIT MORE WIDESPREAD UPSTREAM IN CANADA. AS A
RESULT...UPDATED THE SKY GRIDS TO INCREASE CLOUD COVER NORTH BASED
ON THE CURRENT OBS AND 06Z NAM 1000MB-850MB LAYER RH TRENDS.
THE REMAINING WEATHER ELEMENTS ARE IN GOOD SHAPE. THE UPDATED
PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 634 AM CDT MON SEP 8 2014
GIVEN SATELLITE AND SURFACE OBSERVATION TRENDS THROUGH 11
UTC...THE COLD FRONT IS ARRIVING A BIT EARLIER INTO FAR NORTHEAST
MONTANA AND NORTHWEST NORTH DAKOTA THAN PREVIOUSLY FORECAST. THE
10 UTC RAP AND 06 UTC NAM HAVE CAPTURED THIS WELL...AND HAVE
BLENDED THE PREVIOUS FORECAST TO THEIR SOLUTIONS. THE RESULT...IS
HIGHS ONLY IN THE UPPER 50S ACROSS THE FAR NORTHWEST UNDER LOW
LEVEL STRATUS...AND UPPER 80S FOCUSED CLOSER TO THE SOUTH DAKOTA
BORDER.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT MON SEP 8 2014
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE THE ONSET OF
A MAJOR PATTERN CHANGE LATER TODAY INTO TONIGHT.
CURRENTLY...ARCTIC COLD FRONT...MODIFIED/WARMED AS IT HAS MOVED
SOUTH ACROSS CENTRAL CANADA...CONTINUES TO PUSH SLOWLY SOUTHWARD
ACROSS THE CENTRAL CANADIAN PRAIRIE PROVINCES AHEAD OF/IN RESPONSE
TO A STRONG EMBEDDED IMPULSE ROTATING AROUND A DEEP AREA OF UPPER
LEVEL LOW PRESSURE BUILDING ACROSS THE NORTHERN HUDSON BAY REGION.
AHEAD OF THE FRONT...WAA SPREADING EAST ACROSS THE NORTHERN PLAINS
ALONG TO SOUTH OF A SFC TROUGH.
THE MODIFIED ARCTIC COLD FRONT WILL CONTINUE TO PUSH SOUTH
REACHING THE INTERNATIONAL BORDER 12-15Z...AND THROUGH WEST AND
CENTRAL NORTH DAKOTA LATER THIS EVENING. WILL INITIALLY SEE AN
INCREASE IF LOW TO MID LEVEL CLOUDS ACROSS THE NORTH...ALONG WITH
A WIND SHIFT FROM SOUTHERLY TO NORTHERLY. WILL KEEP THE FORECAST
DRY THROUGH THE AFTERNOON WHEN MOISTURE IS MORE LIMITED. THE
TIMING/PLACEMENT OF THE FRONT WILL CREATE A LARGE SPREAD IN
DAYTIME HIGH TEMPERATURES TODAY...WITH MID/UPPER 60S NORTH AND
MID/UPPER 80S SOUTH.
DEEP LAYER MOISTURE WILL FILTER SOUTHWARD AFTER 00Z BEHIND THE
FROPA...ALONG WITH A MODERATE NORTHEASTERLY UPSLOPE LOW LEVEL FLOW
COMPONENT DEVELOPING NORTH TO SOUTH WITH LOW PRESSURE BUILDING
ACROSS SOUTH DAKOTA. WILL MAINTAIN SLIGHT CHANCES FOR SHOWERS AS
COVERAGE APPEARS TO BE LIMITED. STRATUS DEVELOPMENT LOOKING LIKELY
SO KEPT SKY COVER ELEVATED. REMOVED THUNDER WITH LITTLE
INSTABILITY ADVERTISED BY MODELS. DESPITE THE 0C ISOTHERM ENTERING
MY NORTH LATE TONIGHT...CLOUD COVER SHOULD KEEP TEMPERATURES WELL
ABOVE FROST/FREEZING THRESHOLDS FOR TONIGHT/TUESDAY MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 343 AM CDT MON SEP 8 2014
MUCH COOLER WEATHER AND FROST POTENTIAL CONTINUE TO HIGHLIGHT THE
EXTENDED FORECAST.
THE 00 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN GOOD AGREEMENT
ON COOL HIGH PRESSURE BUILDING ACROSS NORTH DAKOTA TUESDAY THROUGH
THURSDAY...WITH THE POTENTIAL COMMENCEMENT OF RETURN FLOW ACROSS
THE NORTHERN PLAINS AND THE BEGINNING OF A WARMING TREND THIS
WEEKEND AS THE HIGH WEAKENS AND DEPARTS IN THE GREAT LAKES. FROST
IS POSSIBLE ACROSS WESTERN NORTH DAKOTA TUESDAY NIGHT...AND AREA
WIDE WEDNESDAY AND THURSDAY NIGHTS WITH LOWS IN THE 30S. DEPENDING
ON CLOUD COVER...SOME LOCATIONS MAY DROP BELOW FREEZING THURSDAY
NIGHT. IN REGARDS TO PRECIPITATION...ANY SIGNIFICANT PRECIPITATION
IS EXPECTED TO REMAIN TO OUR SOUTH AND EAST AS A COLORADO LOW
PROPAGATES INTO THE MISSISSIPPI VALLEY TUESDAY INTO WEDNESDAY.
SCATTERED RAIN SHOWERS ARE EXPECTED ON TUESDAY... WITH PERHAPS A
RELATIVELY DRY WEDNESDAY WITH SOME SUBSIDENCE BEHIND THE TUESDAY
SHORTWAVE. THE DISTURBANCE THAT HAD THE BEST POTENTIAL TO POSSIBLY
YIELD SOME SNOW ACROSS NORTH DAKOTA THURSDAY IS NOW FORECAST TO
MISS ALL BUT PERHAPS THE VERY FAR SOUTHWEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 634 AM CDT MON SEP 8 2014
A STRONG COLD FRONT IS BEGINNING TO ARRIVE INTO FAR NORTHWEST NORTH
DAKOTA AS OF 1130 UTC...MOVING SOUTHEAST THROUGH THE DAY. IFR
STRATUS ASSOCIATED WITH THE FRONT MAY IMPACT KISN AND KMOT THIS
MORNING INTO THE EARLY AFTERNOON. MVFR TO NEAR IFR STRATUS IS
FORECAST TO OVERSPREAD ALL OF WESTERN AND CENTRAL NORTH DAKOTA
THIS EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TM
SHORT TERM...NH
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
635 AM CDT MON SEP 8 2014
.UPDATE...
ISSUED AT 634 AM CDT MON SEP 8 2014
GIVEN SATELLITE AND SURFACE OBSERVATION TRENDS THROUGH 11
UTC...THE COLD FRONT IS ARRIVING A BIT EARLIER INTO FAR NORTHEAST
MONTANA AND NORTHWEST NORTH DAKOTA THAN PREVIOUSLY FORECAST. THE
10 UTC RAP AND 06 UTC NAM HAVE CAPTURED THIS WELL...AND HAVE
BLENDED THE PREVIOUS FORECAST TO THEIR SOLUTIONS. THE RESULT...IS
HIGHS ONLY IN THE UPPER 50S ACROSS THE FAR NORTHWEST UNDER LOW
LEVEL STRATUS...AND UPPER 80S FOCUSED CLOSER TO THE SOUTH DAKOTA
BORDER.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT MON SEP 8 2014
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE THE ONSET OF
A MAJOR PATTERN CHANGE LATER TODAY INTO TONIGHT.
CURRENTLY...ARCTIC COLD FRONT...MODIFIED/WARMED AS IT HAS MOVED
SOUTH ACROSS CENTRAL CANADA...CONTINUES TO PUSH SLOWLY SOUTHWARD
ACROSS THE CENTRAL CANADIAN PRAIRIE PROVINCES AHEAD OF/IN RESPONSE
TO A STRONG EMBEDDED IMPULSE ROTATING AROUND A DEEP AREA OF UPPER
LEVEL LOW PRESSURE BUILDING ACROSS THE NORTHERN HUDSON BAY REGION.
AHEAD OF THE FRONT...WAA SPREADING EAST ACROSS THE NORTHERN PLAINS
ALONG TO SOUTH OF A SFC TROUGH.
THE MODIFIED ARCTIC COLD FRONT WILL CONTINUE TO PUSH SOUTH
REACHING THE INTERNATIONAL BORDER 12-15Z...AND THROUGH WEST AND
CENTRAL NORTH DAKOTA LATER THIS EVENING. WILL INITIALLY SEE AN
INCREASE IF LOW TO MID LEVEL CLOUDS ACROSS THE NORTH...ALONG WITH
A WIND SHIFT FROM SOUTHERLY TO NORTHERLY. WILL KEEP THE FORECAST
DRY THROUGH THE AFTERNOON WHEN MOISTURE IS MORE LIMITED. THE
TIMING/PLACEMENT OF THE FRONT WILL CREATE A LARGE SPREAD IN
DAYTIME HIGH TEMPERATURES TODAY...WITH MID/UPPER 60S NORTH AND
MID/UPPER 80S SOUTH.
DEEP LAYER MOISTURE WILL FILTER SOUTHWARD AFTER 00Z BEHIND THE
FROPA...ALONG WITH A MODERATE NORTHEASTERLY UPSLOPE LOW LEVEL FLOW
COMPONENT DEVELOPING NORTH TO SOUTH WITH LOW PRESSURE BUILDING
ACROSS SOUTH DAKOTA. WILL MAINTAIN SLIGHT CHANCES FOR SHOWERS AS
COVERAGE APPEARS TO BE LIMITED. STRATUS DEVELOPMENT LOOKING LIKELY
SO KEPT SKY COVER ELEVATED. REMOVED THUNDER WITH LITTLE
INSTABILITY ADVERTISED BY MODELS. DESPITE THE 0C ISOTHERM ENTERING
MY NORTH LATE TONIGHT...CLOUD COVER SHOULD KEEP TEMPERATURES WELL
ABOVE FROST/FREEZING THRESHOLDS FOR TONIGHT/TUESDAY MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 343 AM CDT MON SEP 8 2014
MUCH COOLER WEATHER AND FROST POTENTIAL CONTINUE TO HIGHLIGHT THE
EXTENDED FORECAST.
THE 00 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN GOOD AGREEMENT
ON COOL HIGH PRESSURE BUILDING ACROSS NORTH DAKOTA TUESDAY THROUGH
THURSDAY...WITH THE POTENTIAL COMMENCEMENT OF RETURN FLOW ACROSS
THE NORTHERN PLAINS AND THE BEGINNING OF A WARMING TREND THIS
WEEKEND AS THE HIGH WEAKENS AND DEPARTS IN THE GREAT LAKES. FROST
IS POSSIBLE ACROSS WESTERN NORTH DAKOTA TUESDAY NIGHT...AND AREA
WIDE WEDNESDAY AND THURSDAY NIGHTS WITH LOWS IN THE 30S. DEPENDING
ON CLOUD COVER...SOME LOCATIONS MAY DROP BELOW FREEZING THURSDAY
NIGHT. IN REGARDS TO PRECIPITATION...ANY SIGNIFICANT PRECIPITATION
IS EXPECTED TO REMAIN TO OUR SOUTH AND EAST AS A COLORADO LOW
PROPAGATES INTO THE MISSISSIPPI VALLEY TUESDAY INTO WEDNESDAY.
SCATTERED RAIN SHOWERS ARE EXPECTED ON TUESDAY... WITH PERHAPS A
RELATIVELY DRY WEDNESDAY WITH SOME SUBSIDENCE BEHIND THE TUESDAY
SHORTWAVE. THE DISTURBANCE THAT HAD THE BEST POTENTIAL TO POSSIBLY
YIELD SOME SNOW ACROSS NORTH DAKOTA THURSDAY IS NOW FORECAST TO
MISS ALL BUT PERHAPS THE VERY FAR SOUTHWEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 634 AM CDT MON SEP 8 2014
A STRONG COLD FRONT IS BEGINNING TO ARRIVE INTO FAR NORTHWEST NORTH
DAKOTA AS OF 1130 UTC...MOVING SOUTHEAST THROUGH THE DAY. IFR
STRATUS ASSOCIATED WITH THE FRONT MAY IMPACT KISN AND KMOT THIS
MORNING INTO THE EARLY AFTERNOON. MVFR TO NEAR IFR STRATUS IS
FORECAST TO OVERSPREAD ALL OF WESTERN AND CENTRAL NORTH DAKOTA
THIS EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...NH
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
935 AM CDT MON SEP 8 2014
.DISCUSSION...
LOW CLOUDINESS HANGING ON ACROSS MUCH OF THE MID STATE THIS
MORNING. THE CLEARING LINE EXTENDS FROM JUST EAST OF CKV SOUTHWEST
THROUGH LOBELVILLE. THE LATEST 12Z SOUNDING PAIRED WITH THE NAM
THINKING INDICATES THAT THESE CLOUDS ARE GOING TO BE RATHER TOUGH
TO DISLODGE. THEREFORE...FOR THE UPDATE...WILL GO AHEAD AND LOWER
TEMPS A GOOD 3-5 DEGREES OR SO...MAINLY FOR THE EASTERN HALF OF
THE AREA. WILL ADJUST SKY GRIDS ACCORDINGLY.
OTW...WILL KEEP A SLIGHT CHANCE OF SHOWERS AND TSTMS GOING ACROSS
THE PLATEAU. LATEST HRRR DOES SHOW SOME CONVECTIVE DEVELOPMENT
THIS AFTERNOON. WILL REMOVE THE MORNING 12Z-18Z PART OF THE
SLIGHT CHANCE WEATHER GRID.
UPDATE OUT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 653 AM CDT MON SEP 8 2014/
UPDATE...FOR 12Z AVIATION FORECASTS.
AVIATION...BAND OF LOW CLOUDS THAT COVERED THE SOUTHEASTERN TWO-
THIRDS OF MIDDLE TN EARLY THIS MORNING, WILL SLOWLY BREAK FROM THE
WEST. MVFR CIGS ARE EXPECTED TO HOLD AT BNA THROUGH 18Z, WITH CSV
HOLDING ON TO IFR CONDITIONS THROUGH 15Z, THEN MVFR THROUGH AT
LEAST 20Z. MEANWHILE, CKV SHOULD CONTINUE TO ENJOY VFR CONDITIONS.
FOR TONIGHT...EXPECT CKV AND BNA TO EXPERIENCE VFR CONDITIONS,
WHILE CSV WILL PROBABLY STILL BE PESTERED BY PERIODS OF LOW CLOUDS
AND FOG, ESPECIALLY DURING THE LATTER PART OF THE NIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 86 65 90 70 / 10 05 0 05
CLARKSVILLE 85 61 88 68 / 05 05 0 05
CROSSVILLE 79 64 83 68 / 30 10 20 05
COLUMBIA 85 66 90 67 / 10 05 0 05
LAWRENCEBURG 85 66 89 68 / 10 05 05 05
WAVERLY 85 63 88 69 / 05 05 0 05
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS PUEBLO CO
341 PM MDT MON SEP 8 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 340 PM MDT MON SEP 8 2014
...LOCALIZED FLASH FLOOD POTENTIAL ALONG THE CONTINENTAL DIVIDE
TONIGHT...
CONVECTION HAS BEEN SLOW TO GET GOING ACROSS THE AREA TODAY...IN
PART BY CLOUD COVER OUT WEST WHICH HAS HINDERED HEATING...AND IN
PART BY FALLING DEW POINTS ACROSS THE I-25 CORRIDOR AND SOUTHEAST
PLAINS WHICH HAS LIMITED CAPE. LOCAL HRRR BREAKS OUT STRONGER
CONVECTION ACROSS THE MOUNTAINS DURING THE LATE AFTERNOON AS WELL AS
ALONG A SFC TROF AXIS ACROSS THE SOUTHEAST PLAINS. OVERALL...CAPES
ARE NOT ALL THAT HIGH...SO THINK THIS CONVECTION WILL BE ON THE WEAK
SIDE. HOWEVER...THERE IS SUFFICIENT MOISTURE IN THE ATMOSPHERE FOR
HEAVY ENOUGH RAINFALL TO CAUSE PROBLEMS FOR BURN
SCARS...PARTICULARLY OUT WEST WHERE THEY ARE STEADILY INCREASING.
INTERESTINGLY...HRRR SEEMS TO BE BACKING OFF ON QPF ACROSS THE
SOUTHWEST MOUNTAINS THIS AFTERNOON BUT NAM12 AND OTHER VARIOUS HIGH
RES MODELS STILL SUGGEST THE THREAT IS THERE.
GREATER THREAT FOR FLASH FLOODING FOR THE SOUTHWEST MOUNTAINS STILL
APPEARS TO COME IN DURING THE OVERNIGHT HOURS AS THE SHORTWAVE
ACROSS EAST CENTRAL AZ LIFTS SLOWING TO THE NORTHEAST INTO NRN NM
OVERNIGHT. ALSO WATCHING A VERY DISCERNIBLE SHORTWAVE ACROSS
WESTERN UT WHICH WILL BE MOVING ACROSS THE AREA AT THE SAME TIME
THAT MONSOON MOISTURE ADVECTS INTO THE SOUTHWEST MOUNTAINS.
PRECIPITABLE WATERS INCREASE TO NEAR AN INCH AT PAGOSA SPRINGS AS H7
WINDS IN THE NAM INCREASE FROM THE SOUTHWEST. THIS COMPONENT
PROVIDES THE MOST FAVORABLE UPSLOPE COMPONENT INTO THE EASTERN SAN
JUAN MOUNTAINS. ALL THIS SHOULD MEAN SHOWERS AND THUNDERSTORMS WILL
EXPAND IN AREAL COVERAGE OVERNIGHT (AFTER 06Z) AS LIFT AND MOISTURE
INCREASE WITH THE INCOMING WAVES. ALTHOUGH THE MODELS PORTRAY
VARIOUS SCENARIOS AS TO WHERE THE QPF MAXIMUM WILL OCCUR...THERE ARE
SUFFICIENT SIGNALS IN THE MODEL DATA TO SUGGEST A HEAVY RAINFALL
POTENTIAL SIGNIFICANT ENOUGH TO WARRANT A FLASH FLOOD WATCH FOR THE
EASTERN SAN JUAN MOUNTAINS WERE UPSLOPE MAY REGENERATE SHOWERS AND
THUNDERSTORMS WHICH COULD TRAIN OVER THE SAME SPOTS AS THEY MOVE OFF
TO THE NORTHEAST. STORM MOTIONS SHOULD BE FAST...BUT REPETITIVE
RAINFALL ON THE SAME LOCATION MAY CAUSE FLASH FLOOD PROBLEMS WITH
THE WEST FORK BURN SCAR BEING MOST UNDER THE GUN. REALLY CAN`T RULE
OUT HEAVY RAIN ANYWHERE ACROSS WESTERN PORTIONS OF THE FORECAST
AREA...BUT THREAT SEEMS HIGHEST ACROSS THE SOUTHWEST MOUNTAINS DUE
TO THE UPSLOPE AND PROXIMITY TO THE BURN SCAR SO WILL LIMIT FLASH
FLOOD WATCH TO THAT AREA FOR NOW.
ONE WAVE OF PRECIPITATION WILL SPREAD EASTWARD ACROSS THE AREA LATE
TONIGHT...WITH SCATTERED SHOWERS SPREADING INTO THE PIKES PEAK
REGION TOWARDS DAWN. THIS INITIAL BATCH STILL LOOKS RATHER LIGHT AS
IT MOVES EAST OF THE CONTDVD...AND QUICKLY SKIRTS OFF TO THE EAST
DURING THE MORNING. THEN THE MAIN PACIFIC TROF MOVES IN DURING THE
AFTERNOON. THIS SHOULD ENHANCE SHOWERS AND THUNDERSTORMS OVER THE
MOUNTAINS AGAIN DURING THE AFTERNOON WHICH WILL KEEP THE THREAT FOR
LOCALIZED FLASH FLOODING GOING ACROSS THE SOUTHWEST MOUNTAINS.
STILL NOT STRONG ENOUGH SIGNALS TO SUGGEST FLASH FLOODING FOR THE
SOUTHEAST MTS/PLAINS. LOW LEVEL WINDS ARE WESTERLY WHICH IS
DOWNSLOPE...AND AS A RESULT...DEW POINTS...WHICH DO INCREASE
SOME...ARE STILL ONLY IN THE 40S. THIS RESULTS IN CAPES OF ONLY A
FEW HUNDRED J/KG DURING THE AFTERNOON. SHOWERS AND THUNDERSTORMS
WILL MOVE OFF THE MOUNTAINS DURING THE AFTERNOON...AND WILL ALSO
BECOME FOCUSED ALONG A FRONT WHICH DROPS SOUTH OF THE PALMER DIVIDE
BETWEEN 21Z AND 00Z. CONVECTIVE BULLS-EYES ACROSS THE SOUTHEAST
PLAINS MEANDER FROM RUN TO RUN...BUT PARAMETERS ARE NOT FAVORABLE TO
PIN PRECIPITATION TO THE SOUTHEAST MOUNTAINS LONG ENOUGH TO CAUSE
PROBLEMS. STORM MOTIONS WILL BE TO THE EAST AT A PRETTY GOOD CLIP.
WILL KEEP MAINLY ISOLATED POPS FOR THE PLAINS DURING THE
AFTERNOON...WITH POPS INCREASING INTO THE EVENING HOURS AS THE FRONT
MOVES THROUGH.
TEMPERATURES TONIGHT WILL BE MILD WITH INCREASING CLOUD COVER.
HIGHS ON TUESDAY WILL BE COOLER OUT EAST WITH MORE WIDESPREAD
PRECIPITATION. MEANWHILE...WESTERLY DOWNSLOPE WINDS WILL BATTLE
CLOUD COVER AT TIMES ACROSS THE SOUTHEAST PLAINS...BUT OVERALL KEPT
MAX TEMPERATURES ON THE WARM SIDE. -KT
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 340 PM MDT MON SEP 8 2014
.TUESDAY NIGHT AND WEDNESDAY...SHOWERS AND THUNDERSTORMS WILL
LINGER INTO THE EVENING AS THE TROUGH PASSES THOUGH FROM THE
NORTHWEST. ANY CAPE SHOULD END BY LATER IN THE EVENING AS THE
COOLER MORE STABLE AIR MOVES INTO THE REGION. OVER THE
MOUNTAINS...LOWER LEVEL COLD AIR WILL BE TOO SHALLOW TO PASS OVER
THE EASTERN MOUNTAINS. KEPT SCATTER POPS OVER THE MOUNTAINS
OVERNIGHT AND INTO WEDNESDAY MORNING AS TROUGH WILL NOT PASS
THROUGH THE REGION UNTIL EARLY WEDNESDAY. ON WEDNESDAY...DRIER
AIR MASS ALOFT MOVES INTO THE REGION. ON THE PLAINS...ANOTHER
SURGE OF COOLER AIR MOVES INTO THE REGION BEHIND THE TROUGH.
ATMOSPHERE WILL BE TOO STABLE OVER THE PLAINS DURING THE DAY.
BUKFIT SOUNDINGS SUGGEST THERE MAY BE ENOUGH HEATING FOR SOME
LATER AFTERNOON THUNDERSTORMS ALONG THE INTERSTATE 25 CORRIDOR AND
OVER THE EASTERN MOUNTAINS. BY THE EVENING...THE COOL AIR ON THE
PLAINS MAY BECOME DEEP ENOUGH TO PRODUCE SOME VERY LIGHT SHOWERS
AND KEPT ISOLATED POPS IN THE GRIDS.
.THURSDAY AND FRIDAY...MODELS AND ENSEMBLES AGREE ON HAVING A
SHARPER TROUGH PASSING OVER THE REGION LATE THURSDAY INTO FRIDAY.
EC IS SLOWER...DEEPER AND COLDER WITH THE TROUGH. EC HAS 700MB
APPROACHING -4C OVER EL PASO COUNTY FRIDAY MORNING WHILE GFS IS
CLOSER TO +2C. ANTICIPATE A REASONABLE CHANCE OF LIGHT RAIN
THURSDAY EVENING AS THE TROUGH APPROACHES WITH THE COLD FRONTAL
PASSAGE. EC SOLUTION SUGGEST A BETTER CHANCE FOR PRECIPITATION THURSDAY
NIGHT. BEST CHANCES APPEAR TO BE FROM THE EASTERN MOUNTAINS AND
EASTWARD ASSOCIATED WITH THE MORE MOISTURE UPSLOPE FLOW. FRIDAY
HAS THE POTENTIAL TO BE A CHILLY AND CLOUDY DAY ON THE PLAINS AND
EASTERN MOUNTAINS. EXTENDED PROCEDURE GAVE HIGHS IN THE 50S OVER
THE PLAINS FRIDAY...WITH LOW CLOUDS LINGERING UNTIL AT LEAST MID
AFTERNOON. DEPENDING ON THE SPEED OF THE SYSTEM AND THE AMOUNT OF
CLOUDINESS...HIGH TEMPERATURES COULD EVEN BE COOLER. LOW LEVEL
COLD AIR MASS WILL MOSTLY STAY EAST ALONG AND EAST OF THE
EASTERN MOUNTAINS. WITH WARMING AND DRYING ALOFT...IT COULD BE A
SUNNY AND MILD DAY OVER THE REMAINING MOUNTAINS AND HIGH VALLEYS.
.SATURDAY THROUGH MONDAY...WILL HAVE TO WATCH FOR THE POTENTIAL
OF SOME FROST SATURDAY MORNING...DEPENDING ON THE AMOUNT OF
CLEARING. AFTERWARDS...A WARMING TREND WILL DEVELOP FOR THE
WEEKEND ESPECIALLY OVER THE PLAINS AND EASTERN MOUNTAINS AS THE
SURFACE HIGH MOVES EAST OF THE REGION. SOME MONSOON MOISTURE COULD
MOVE INTO THE MOUNTAINS OVER THE WEEKEND...AND INCREASED POPS
SLIGHTLY. OVER THE PLAINS...LOW LEVEL MOISTURE WILL RETURN ON
SUNDAY AND MONDAY...AND THE INCREASED MOISTURE COULD RESULT IN A
FEW AFTERNOON AND EVENING STORMS. --PGW--
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 340 PM MDT MON SEP 8 2014
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO INCREASE ACROSS THE
REGION TONIGHT...PARTICULARLY ALONG THE CONTINENTAL DIVIDE WHERE
WIDESPREAD MTN OBSCURATIONS WILL DEVELOP AFTER MIDNIGHT.
KALS...KCOS...AND KPUB WILL CONTINUE TO SEE VFR CIGS AT TIMES WITH
SHOWERS AND THUNDERSTORMS POSSIBLE LATE THIS AFTERNOON IN THE VCNTY
OF THE AIRPORTS...THEN AGAIN TOWARDS TUESDAY MORNING AS A
DISTURBANCE MOVES ACROSS THE REGION. SOME CLEARING WILL TAKE PLACE
DURING THE LATE MORNING AND EARLY AFTERNOON BEFORE ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS ROLLS OFF THE MOUNTAINS DURING THE
AFTERNOON. THESE TOO MAY PRODUCE VFR TO LOCAL MVFR CIGS/VIS AS THEY
MOVE ACROSS THE REGION. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH TUESDAY AFTERNOON FOR COZ067-068.
&&
$$
SHORT TERM...KT
LONG TERM...PGW
AVIATION...KT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1057 AM MDT MON SEP 8 2014
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 411 AM MDT MON SEP 8 2014
MODEL DATA CONTINUES TO SHOW EXCELLENT CONTINUITY REGARDING THE
INTERACTION OF UPPER TROUGH ALONG THE CALIFORNIA COAST AND
MOISTURE PLUME (WHICH INCLUDES THE REMAINS OF NORBERT). MOISTURE
PLUME ARCS FROM THE LOWER COLORADO RIVER BASIN INTO SW UTAH...
EVENTUALLY SPREADING EAST INTO WRN COLORADO AS THE DAY PROGRESSES
TODAY. IN THE SHORT TERM OUTLOOK...THE HRRR SHOWS THE AREA OF PCPN
OVER PARTS OF SW COLORADO (OR WRN PORTION OF THE SAN JUAN
MOUNTAINS) WILL SHIFT NORTHWARD EARLY THIS MORNING AND BE
POSITIONED OVER THE I70 CORRIDOR AROUND DAYBREAK. HAVE NOT SEEN
THIS NORTHWARD TREND YET...BUT SEEMS REASONABLE AS ISENTROPIC
UPGLIDE AND INCREASING MOISTURE FROM THE WEST ACCOUNTS FOR AN
INCREASING CHANCE OF RAIN. SPECIFIC HUMIDITIES AT 700 MB IS QUITE
HIGH WITH VALUES RANGING FROM 8 TO 10 G/KG. PRECIPITABLE WATER AT
KGJT IS PROGGED TO BE 1.25 INCHES BY 00Z THIS EVENING (PER RAP13)...
WHICH IS PLUS 3 STANDARD DEVIATIONS ABOVE NORMAL. USED THE DAY 1
EXCESSIVE RAINFALL OUTLOOK TO FINE TUNE THE FLASH FLOOD WATCH.
THE ONLY AREAS OUTSIDE THE EXCESSIVE RAINFALL IS PARTS OF NE
UTAH...WRN MOFFAT COUNTY AND ARCHULETA COUNTY AND THE ERN EDGE OF
OUR FORECAST AREA.
TONIGHT DEEP MOISTURE CONTINUES TO ADVECT IN FROM THE SW UP TO 1.3
INCHES IN SE UTAH AND EVEN UP TO 1.6 INCHES IN THE 00Z NAM12. THIS
IS VERY HIGH FOR EARLY SEPTEMBER...GREATER THAN TWO STANDARD
DEVIATIONS ABOVE NORMAL. THE SATURATED VERTICAL PROFILE WITH WET
BULB ZERO/ICE PRODUCTION LEVEL AROUND 10KFT WILL NOT NEED DEEP
CONVECTIVE CELLS TO PRODUCE HEAVY RAINFALL. SO THIS WILL MAKE THE
RADAR OBSERVATIONS DIFFICULT TO CAPTURE SOME OF THE HEAVIEST
SHOWERS OCCURRING IN THE FOUR CORNERS REGION. STORM MOTION WILL BE
QUICK THOUGH TO THE ENE AT 20KTS INCREASING TO 30 KTS BY EARLY
TUESDAY MORNING. SOME SHOWERS WILL BE MIXING THESE WINDS DOWN TO
THE SURFACE. THIS IS NOT CAPTURED WELL IN MOS GUIDANCE.
TUESDAY THE BROAD TROUGH WORKS THROUGH THE GREAT BASIN AND INTO
THIS CWA BY LATE AFTERNOON. GRADIENT WINDS VEERS FROM SW TO W AND
INCREASE TO 30 TO 50 KTS IN THE 0-6KM LAYER. THIS WEST FLOW WILL
BEGIN TO ERODE MOISTURE IN THE MID LEVELS ADDING TO AFTERNOON
INSTABILITY. PRECIP WATER VALUES FALL BELOW ONE INCH IN THE
AFTERNOON. JET SUPPORT PASSES THROUGH WYOMING BUT POTENTIAL VORT
FIELDS SHOW SOME FORCING ACROSS THE NORTH. SO CHANCES FOR STRONGER
CONVECTIVE CELLS INCREASE TUESDAY AFTERNOON ESPECIALLY OVER THE
NORTH. GUSTY WINDS AND SMALL HAIL ARE POSSIBLE. HEAVIER RAIN
SHOWERS PERSIST IN THE SOUTH. EXPECT A COOL DAY UNDER WIDESPREAD
CLOUDS AND SHOWERS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 411 AM MDT MON SEP 8 2014
TUESDAY NIGHT...WITH TROUGH PASSAGE OVERNIGHT THE FLOW VEERS TO A
DRIER NW AND PRECIP WATER VALUES DROP TO AROUND 0.5 INCHES FOR ALL
BUT THE SOUTHERN MOST ZONES. SHOWERS ARE EXPECTED TO ERODE FROM
WEST TO EAST THROUGH THE EVENING. THERE MAY BE SOME THREAT OF
LOCALIZED MORNING FOG.
WEDNESDAY-WEDNESDAY NIGHT...A FEW AFTERNOON SHOWERS MAY FORM IN
THE EASTERN MOUNTAINS WEDNESDAY AFTERNOON IN RESIDUAL MOISTURE.
OTHERWISE PLENTY OF SUN RETURNS TO THE FORECAST AREA. TEMPERATURES
REMAIN BELOW NORMAL. LIGHT WINDS AND CLEARING SKIES WEDNESDAY
NIGHT SHOULD ALLOW FOR MODERATE TO STRONG SURFACE BASED INVERSIONS
AND COOL OVERNIGHT LOW TEMPERATURES.
THURSDAY THROUGH SUNDAY...DRY AND STABLE NORTHWEST FLOW IS
EXPECTED TO PREVAIL THROUGH THIS PERIOD. RIDGE AXIS AMPLIFIES OVER
THE WRN STATES WITH TIME. AFTERNOON TEMPS WILL HAVE RECOVERED FROM
THE RAIN COOLED AIR MASS WITH PLENTY OF DAYTIME SUNSHINE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1055 AM MDT MON SEP 8 2014
MOISTURE CONTINUES TO STREAM INTO EASTERN UTAH AND WESTERN
COLORADO THIS MORNING. LIFT HAS BEEN UNFOCUSED WITH MAINLY
ISOLATED TO SCATTERED SHOWERS DRIFTING THROUGH WITH MINIMAL
IMPACTS TO FORECAST TERMINALS. HEATING OF THE DAY WILL HELP BOOST
CONVECTION THIS AFTERNOON AND THE SHOWERS AND THUNDERSTORMS WILL
BECOME MORE WIDESPREAD. OVERALL LIFT INCREASES OVERNIGHT INTO
TUESDAY LEAVING NUMEROUS SHOWERS AND THUNDERSTORMS IN PLACE ACROSS
THE REGION. THEREFOR TERMINAL FORECASTS WILL BE OPTIMISTIC IN THE
FIRST 6 TO 12 HOURS...THEN BECOME INCREASING PESSIMISTIC WITH
BETTER CHANCES OF IFR/MVFR CONDITIONS. OBSCURATION OF THE
HIGHER TERRAIN WILL ALSO BECOME WIDESPREAD THIS AFTERNOON THROUGH
TOMORROW EVENING BEFORE DRYING MOVES IN BEHIND THIS SYSTEM.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR COZ002>014-017>022.
UT...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR UTZ022-025-027>029.
&&
$$
SHORT TERM...PF/JOE
LONG TERM...JOE/PF
AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
258 PM CDT MON SEP 8 2014
.DISCUSSION...
247 PM CDT
MAIN CONCERNS FOR THE FORECAST PERIOD WILL FOCUS ON THUNDERSTORMS
AND HEAVY RAINFALL ASSOCIATED WITH AN UNUSUALLY STRONG LATE SUMMER
COLD FRONT AND UPPER TROUGH IMPACTING THE REGION FROM TUESDAY NIGHT
INTO WEDNESDAY NIGHT. FOLLOWING THE PASSAGE OF THIS SYSTEM...THE
FOCUS WILL SHIFT TO THE TEMPERATURE FORECAST AND THE FIRST REAL
TASTE OF AUTUMNAL WEATHER FOR LATER THIS WEEK.
FOR THE REMAINDER OF THIS AFTERNOON INTO THE EVENING...CONTINUOUS
WILL REMAIN QUIET. THE ONLY ITEM OF CONCERN IS AN OLD MCS TRACKING
ACROSS NRN IOWA. DO NOT ANTICIPATE THAT ANY PCPN WILL HANG TOGETHER
LONG ENOUGH TO IMPACT THE CWA...BUT RATHER EXPECT INCREASING MID AND
HIGH CLOUDS ENCROACHING ON THE NRN PORTIONS OF THE CWA.
THE FLOW PATTERN ALOFT CONTINUES TO BE VERY LOW AMPLITUDE WITH THE
FASTER WESTERLIES ACROSS THE NRN CONUS AND BROAD RIDGING OVER THE
SRN CONUS. WEAK SHORTWAVES RIPPLING THROUGH THE FAST ZONAL FLOW
ALOFT WILL BRING THE INITIAL CHANCES FOR PCPN LATE TONIGHT. THE
ANTICIPATED TRACK OF THE ASSOCIATED SHORT WAVE WOULD BRING THE
GREATEST CHANCE FOR SHOWERS AND SOME SCATTERED
THUNDERSTORMS...MOSTLY AFTER MIDNIGHT WITH SOME LINGERING PCPN
POSSIBLE INTO EARLY TUESDAY MORNING.
THE SYSTEM OF GREATER CONCERN IS SHAPING UP FOR LATE TUESDAY NIGHT
THROUGH WEDNESDAY. THE LARGE SCALE MODELS HAVE BEEN CONSISTENT IN
ADVERTISING A HEAVY RAIN EVENT WITH THE POSSIBILITY OF SEVERE
THUNDERSTORMS. THROUGH TUESDAY...THE UPPER LEVEL PATTERN WILL
UNDERGO AN AMPLIFICATION PROCESS WITH UPPER TROUGHING DEVELOPING
OVER THE WRN CONUS WITH BROAD RIDGING OVER THE CNTRL AND ERN CONUS.
THE UPPER TROUGH WILL TAP SOME RESIDUAL MOISTURE FROM THE REMNANTS
OF EASTERN PACIFIC HURRICANE NORBERT. ADDITIONALLY...LEE TROUGH
DEVELOPMENT OVER THE CENTRAL PLAINS WILL HELP OPEN UP THE GLFMEX AND
INCREASINGLY SOUTHERLY TO SOUTHWESTERLY FLOW AT THE SFC ALOFT WILL
SET UP AN EXTENDED PERIOD OF WARM/MOIST ADVECTION. THE LARGER SCALE
MODEL GUIDANCE HAS BEEN CONSISTENT IN ADVERTISING COPIOUS AMOUNTS OF
MOISTURE POOLING ALONG AND AHEAD OF THE SFC COLD FRONT...WITH AN
AREA OF PWATS IN EXCESS OF 2 INCHES MOVING OVER THE REGION AS THE
COLD FRONT PUSHES EWD ACROSS THE CNTRL PLAINS AND INTO THE MIDWEST.
WITH THE STRONGEST WESTERLY SHUNTING TO THE NORTH WITH THE
AMPLIFYING UPPER LEVEL PATTER...THE ASSOCIATED SFC LOW WILL TAKE A
NELY TRACK FROM THE CNTRL PLAINS TUESDAY INTO CENTRAL WISCONSIN BY
MIDDAY WEDNESDAY...AND THEN THROUGH THE UPPER GREAT LAKES WEDNESDAY
NIGHT. THE NET EFFECT OF THIS EVOLUTION WILL BE TO SLOW THE
PROGRESSION OF THE SRN END OF THE FRONT...WITH EXTENSIVE TRAINING OF
THUNDERSTORMS IN THE DEEPER LEVEL SWLY FLOW ALOFT. WITH THE LATEST
FORECAST UPDATE...WILL CARRY AROUND 2 INCHES OF STORM TOTAL
WIDESPREAD QPF WITH THE SYSTEM FROM LATE TUESDAY NIGHT INTO EARLY
WEDNESDAY EVENING. HOWEVER...WITH TRAINING THUNDERSTORMS LIKELY
ALONG WITH A VERY MOIST AIRMASS...THE 2 INCH AMOUNTS MAY BE A
CONSERVATIVE AREAL AVERAGE AMOUNT AS LOCALIZED TRAINING AND STRONG
TO POTENTIALLY SEVERE THUNDERSTORMS WILL BE VERY EFFICIENT PCPN
PRODUCERS. THE PERIOD OF TIME WHICH THE HEAVIEST RAINFALL IS
EXPECTED WILL BE FROM LATE MORNING THROUGH LATE AFTERNOON WEDNESDAY
AS THE LEADING EDGE OF A 50KT+ LOW LEVEL JET POINTS INTO NRN IL/SERN
WI AND THEN SLOWLY TRANSLATES INTO NWRN INDIANA. THE STRONG VEERING
OF WINDS THROUGH THE LOWER LEVELS SHOULD BE SUFFICIENT TO SUPPORT
STRONG ROTATING UPDRAFTS CONDUCIVE TO SUPERCELL DEVELOPMENT ON THE
LEADING EDGE OF THE LOW LEVEL JET...BUT ACTIVITY SHOULD EVOLVE INTO
MORE ORGANIZED LINES OR CLUSTERS OF STORMS. THE GREATEST SEVERE
THREAT SHOULD BE STRONG...DAMAGING WINDS GIVEN THE STRONG LOW LEVEL
SHEAR. WHILE THE POSSIBILITY OF LARGE HAIL IS NOT OUT OF THE
QUESTION...THE FREEZING LEVEL WILL BE CLOSE TO 16KFT...SO A
CONSIDERABLE AMOUNT OF MELTING COULD OCCUR BEFORE HAIL REACHES THE
GROUND.
THE COLD FRONT SHOULD FINALLY PUSH EAST OF THE CWA...BRINGING AN END
TO ANY LINGERING PCPN OVER THE FAR SERN PORTIONS OF THE CWA BY
DAYBREAK EARLY THURSDAY MORNING. AS THE SFC LOW ASSOCIATED WITH THIS
SYSTEM MOVES OFF INTO THE CANADIAN MARITIME PROVINCES THURSDAY
NIGHT...A BROAD UPPER TROUGH WILL DROP OUT OF CANADA...BRINGING A
SIGNIFICANTLY COLDER AIRMASS ACROSS THE NRN PLAINS AND UPPER
MIDWEST. THE GFS/ECMWF ARE RELATIVELY CONSISTENT ON BRINGING THE 0C
850MB ISOTHERM CLOSE TO THE WISCONSIN BORDER BY THURSDAY EVENING
WHILE BROAD HIGH PRESSURE SPREADS ACROSS THE CNTRL/NRN PLAINS AND
UPPER MISSISSIPPI VALLEY. THROUGH THE DAY ON FRIDAY...THE 0C 850MB
TEMPS ARE EXPECTED TO REACH INTO NRN IL...WHICH IS DOWNRIGHT CHILLY
FOR MID SEPTEMBER. THE TEMPERATURE CONTRAST ACROSS THE COLD FRONT
WILL BE VERY NOTABLE...WITH TEMPERATURES DROPPING OFF FROM THE UPPER
70S TO LOWER 80S ON WEDNESDAY INTO THE MIDDLE 40S TO AROUND 50F
THURSDAY MORNING. STRONG...PERSISTENT COLD ADVECTION THROUGH A DEEP
LAYER OF THE ATMOSPHERE WILL SET UP A MUCH COOLER PERIOD BEGINNING
THURSDAY AND CONTINUING THROUGH THE WEEKEND WITH HIGHS GENERALLY IN
THE UPPER 50S TO LOWER 60S. IF THIS PATTERN WOULD OCCUR JUST A
COUPLE WEEKS LATER...WITH A LOWER SUN ANGLE...THE AREA COULD SEE
HIGHS POTENTIALLY IN THE UPPER 40S TO LOWER 50S. HOWEVER...A HIGHER
SUN ANGLE AND AMPLE SUNSHINE SHOULD LIMIT THE DEGREE OF COOLING.
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK...ONLY EXPECT SLOW
MODERATION TO TEMPERATURES AS A STEADY STREAM OF NRN STREAM
SHORTWAVE ENERGY WILL CONTINUE TO CARVE OUT A BROAD UPPER THROUGH
OVER THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES REGIONS...GIVING
LITTLE OPPORTUNITY FOR ANY SIGNIFICANT WARMING.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SOUTHERLY WINDS SPORADICALLY GUSTING TO OVER 10 KT THIS
AFTERNOON.
* SLIGHT CHANCE FOR SHRA TUESDAY MORNING...WITH A CHANCE FOR TSRA
IN THE WESTERN TRACON AREA.
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE IS BEGINNING TO PULL AWAY WITH SOUTHERLY WINDS
ENCOMPASSING THE AREA. THE WIND DIRECTION AT CHICAGOLAND TAF
SITES HAS AND LIKELY WILL CONTINUE TO BE SOMEWHAT VARIABLE BETWEEN
SOUTHWEST AND SOUTHEAST. WHILE ORD AND MDW OBSERVATIONS HAVE
INDICATED A FEW GUSTS IN EXCESS OF 10 KT...BELIEVE THAT SUCH GUSTS
WILL BE INFREQUENT BASED ON THE ATMOSPHERIC PROFILE THIS
AFTERNOON. PER OBSERVATIONAL TRENDS...THE LAKE BREEZE LOOKS TO
VERY LIKELY STAY EAST OF ORD AND MDW. THE SYNOPTIC WIND WILL
LIKELY STILL OFFER ENOUGH OF A SOUTHEAST COMPONENT TO TURN THE
WINDS SLIGHTLY EAST OF SOUTH FROM TIME TO TIME THIS
AFTERNOON...BUT AGAIN SPEEDS SHOULD BE 6-10 KT MUCH OF THE TIME.
THUNDERSTORMS OVER WESTERN IA HAD DIFFICULTLY EVOLVING EASTWARD
THIS MORNING. AS AN UPPER LEVEL DISTURBANCE MOVES INTO THIS AREA
AND ADVANCED EAST...IT SHOULD HELP SHOWERS AND STORMS TO DO THE
SAME. AN UPTICK IN COVERAGE IS EXPECTED THIS EVE ACROSS EASTERN IA
AND POSSIBLY INTO NORTHWESTERN/WESTERN IL AS THE NIGHT PROGRESSES.
THE ATMOSPHERE FAVORS ANY ORGANIZED AREA OF SHOWERS AND STORMS TO
MOVE SOUTHEAST. RIGHT NOW ITS DIFFICULT TO SAY IF SHOWERS WILL
REMAIN WEST OF CHICAGOLAND SITES TUESDAY MORNING...HOWEVER THERE
IS GREATER CONFIDENCE THAT TSRA WILL STAY WEST/SOUTHWEST THROUGH
TUESDAY MORNING.
A POTENTIALLY ACTIVE AND IMPACTING PERIOD TO AVIATION WEATHER AT
AREA TAF SITES APPEARS TO BE SHAPING UP LATE TUESDAY NIGHT THROUGH
WEDNESDAY WITH A PROBABLE PERIOD OR PERIODS OF STORMS...GUSTY
SOUTHERLY WINDS...AND POTENTIALLY LOW CLOUDS WEDNESDAY MORNING.
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM THAT WINDS WILL NOT FREQUENTLY BE GREATER THAN 10 KT.
* MEDIUM IN SHRA REMAINING WEST OF THE AIRFIELDS TUESDAY MORNING.
HIGH THAT TSRA WILL REMAIN WEST OF THE AIRFIELDS TUESDAY MORNING.
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 18Z...
TUESDAY NIGHT...CHC SHRA/TSRA INCREASING OVERNIGHT. SOUTHERLY
WINDS INCREASING WITH 40 KT FLOW AROUND 1000-1500 FT.
WEDNESDAY...SHRA/TSRA LIKELY ESPECIALLY IN THE MORNING. GUSTY
SOUTHERLY WINDS...AT TIMES TO 25 KT AND POSSIBLY 30 KT. MAINLY
VFR...BUT PATCHY IFR IN STRONGER SHRA/TSRA.
THURSDAY THROUGH SUNDAY...MAINLY VFR.
MTF
&&
.MARINE...
156 PM CDT
THE MAIN FORECAST CONCERNS CENTER AROUND A SIGNIFICANT STORM SYSTEM
EXPECTED TO IMPACT THE GREAT LAKES WEDNESDAY THROUGH THURSDAY.
SOUTHERLY WINDS ARE EXPECTED TO INCREASE RAPIDLY AROUND OR SHORTLY
AFTER DAYBREAK WEDNESDAY AS A STRENGTHENING AREA OF LOW PRESSURE
MOVES FROM IOWA INTO SOUTHWESTERN WISCONSIN. SOUTHERLY GALES OF 35
TO 40 KT ARE PROBABLE BY MID TO LATE MORNING...ESPECIALLY ACROSS THE
SOUTHERN HALF TO 2/3RDS OF THE LAKE...AND THESE STRONG WINDS LOOK TO
CONTINUE THROUGH WEDNESDAY AFTERNOON. THE LOW IS THEN EXPECTED TO
SHIFT SOMEWHERE ACROSS THE NORTHERN PORTION OF THE LAKE BY WEDNESDAY
EVENING. THIS COULD RESULT IN A SHORT PERIOD OF LIGHT AND VARIABLE
WINDS ACROSS NORTHERN SECTIONS OF THE LAKE EARLY WEDNESDAY EVENING.
HOWEVER...ONCE THIS LOW SHIFTS EAST OF THE LAKE BY LATER WEDNESDAY
EVENING...A STRONG COLD FRONT WILL PUSH OVER THE LAKE...WITH A
PERIOD OF NORTHWESTERLY GALES LOOKING LIKE A DECENT BET ACROSS MOST
OF THE LAKE INTO EARLY THURSDAY.
THE WINDS WILL GRADUALLY ABATE SOME INTO THE LATER PORTION OF THE
WEEK AS HIGH PRESSURE BUILDS IN ACROSS THE PLAINS AND UPPER
MIDWEST. HOWEVER...THE NORTHERLY FETCH WILL LIKELY CONTINUE TO
PRODUCE SOME HIGHER 4 + FOOT WAVES THROUGH FRIDAY.
AS FOR HEADLINES...WE HAVE ISSUED A GALE WATCH FOR THE SOUTHERN
2/3RDS OF THE OPEN WATERS FROM 14 UTC WED THROUGH 15 UTC THURS
AND FOR THE NORTHERN PORTION OF THE LAKE FROM 03 UTC THURS THROUGH
15 UTC THURS. HOWEVER...AT THIS TIME I HAVE OPTED TO LEAVE THE
ILLINOIS AND INDIANA NEAR SHORES OUT OF THE GALE WATCH DUE TO THE
OFFSHORE COMPONENT OF THE FLOW AND THEIR PROXIMITY TO THE SURFACE LOW.
HOWEVER...GALE FORCE GUSTS ARE CERTAINLY POSSIBLE IN THE NEAR SHORES
AS WELL...AND THIS MAY NEED TO BE ADDED TO THE WATCH IN FUTURE
FORECAST UPDATES. AT THE VERY LEAST...A HIGH END SMALL CRAFT
ADVISORY WITH WINDS TO 30 KT WILL LIKELY BE NEEDED FOR THE NEAR
SHORE WATERS FOR WEDNESDAY THROUGH THE END OF THE WEEK.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-
LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM WEDNESDAY TO 10 AM THURSDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ563...7 PM WEDNESDAY TO 10
AM THURSDAY.
&&
$$
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
254 PM CDT Mon Sep 8 2014
.SHORT TERM...(Tonight)
ISSUED AT 253 PM CDT MON SEP 8 2014
A surface high pressure ridge across extreme eastern and southeast
IL early this afternoon will gradually shift to the east this
evening. This will allow a light, south return flow to develop. The
18z surface analysis indicated dew points in the lower-middle 50s in
much of central IL. However, moist low level air is as close as west
central MO - so it doesn`t have far to go to make a return to
central IL.
A prominent outflow boundary from northeast to south central IA is
expected to provide the focus for MCS development tonight. The short
range models are is disagreement as to the track of the MCS and its
associated remnants into west central IL overnight. Prefer the RAP,
and to a certain extent a blend of the NAM and GFS, solution of the
eastern edge of the precipitation shield getting close to the IL
Valley after Midnight and just west of I-55 around daybreak. Drier
air in eastern IL should work to erode the eastern edge from
progressing much further.
&&
.LONG TERM...(Tuesday through Monday)
ISSUED AT 253 PM CDT MON SEP 8 2014
Not too many changes needed to the forecast over the next several
days. While minor tweaks are required for the latest model trends,
the overall picture has remained the same.
Relatively low precipitation chances, mainly over the western
portion of the forecast area, are appropriate through Tuesday night.
These PoPs are the result of diurnal convection firing along an
outflow boundary from tonight`s upstream MCS Tuesday and/or from the
approach of our main midweek system by late Tuesday night.
Our main precipitation threat is still on track for Wednesday and
Wednesday night. This will occur courtesy of a potent upper level
wave, associated surface low, and strong trailing cold front. A
decent severe thunderstorm threat also exists ahead of the cold
front, mainly Wednesday afternoon and evening. The main concern for
nailing down too many specifics is the spread that persists with
respect to the speed of trailing cold front. The slower solutions,
most notably the 12Z ECMWF, will offer the most time for instability
to build on Wednesday before the arrival of the front and increase
the severe weather threat. Most models continue to point a general
35-45kt bulk shear gradient from south to north across the forecast
area ahead of the front. A middle of the road solution to
instability, accounting for differences in frontal speed, should
support CAPE values of 1500-2500 j/kg. Heavy rain still looks to be
a threat across the entire forecast area, severe weather or not,
given the precipitable water values in excess of 2 inches forecast
on the warm side of this system ahead of the cold front.
Once the strong cold front clears the area by late Wednesday night,
a much cooler than normal weather pattern should linger through the
end of the forecast period. Upper level troffing should remain in
place, accompanied by a Canadian surface high more often than not.
There are still some stronger waves expected to track through the
mean trof that may produce some rainfall over the last few days of
the forecast. However, model agreement in this regard still leaves
much to be desired. At this point, the best model clustering
suggests showers are possible later Friday into Friday night, and
this is the only period I have left slight chances for showers in
place. Temperatures through the period should average 60s for highs
and 40s for lows.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 100 PM CDT MON SEP 8 2014
VFR conditions can generally be expected the next 24 hours in
central and eastern IL. A surface high pressure ridge will remain
over eastern IL into this evening with a southerly return flow
developing in central IL. However, the biggest question will be
how much return flow of low level moisture occurs, especially west
of I-55. Most of the shorter range models are depicting the
development of another MCS in Iowa overnight. However, they differ
on where the remnants may track. The HRRR seems to be too far
north with its rainfall, while the NAM and RAP keep the bulk of
the thunderstorms in SE Iowa and west central IL closer to the
lower level theta-e ridge.
With the best low level moisture advection/moisture transport
expected to be near the MS River and the forecast of Corfidi
vectors to be pointing toward the southeast, will only put a
mention of VCTS in the forecast for KPIA, with the possibility of
a VCSH along I-55 from KBMI-KSPI Tuesday morning after daybreak.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MILLER
LONG TERM...BAK
AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
157 PM CDT MON SEP 8 2014
.DISCUSSION...
350 AM CDT
PRIMARY FOCUS REMAINS ON DEEP LOW PRESSURE SYSTEM WHICH WILL MOVE
THROUGH THE UPPER MIDWEST TUESDAY NIGHT THROUGH WEDNESDAY...AND
ASSOCIATED RAIN/THUNDER TRENDS. MUCH COOLER AIR ARRIVES LATER
WEDNESDAY NIGHT IN THE WAKE OF THIS SYSTEM...WITH A REINFORCING PUSH
OF COOLER AIR FRIDAY.
IN THE NEAR TERM...ARE REMAINS UNDER INFLUENCE OF SURFACE HIGH
PRESSURE RIDGE TODAY. A SHORT WAVE MOVING NORTH OF THE CWA MAY
SPREAD A LITTLE HIGH CLOUD COVER ALONG WITH SOME CIRRUS FROM
CONVECTION WELL TO OUR NORTHWEST TODAY...THOUGH GENERALLY DRY AND
MILD CONDITIONS EXPECTED. LOW LEVEL MOIST ADVECTION RAMPS UP TO OUR
WEST TONIGHT WITH THUNDERSTORM DEVELOPMENT ANTICIPATED ACROSS THE
UPPER MISSISSIPPI VALLEY. HIGH-RES GUIDANCE FOCUSES ON NORTHEAST
IOWA LATER IN THE NIGHT...WITH INDICATIONS OF MCS REMNANTS MOVING
INTO NORTHWEST LATE AND CONTINUING TO PROPAGATE SOUTHEAST ACROSS
NORTH CENTRAL...WEST CENTRAL AND CENTRAL ILLINOIS AS SYSTEM DECAYS
TUESDAY MORNING. DRIER LOW LEVEL AIR ASSOCIATED WITH THE RETREATING
HIGH TO THE EAST...AND INSTABILITY AXIS FOCUSED FARTHER TO THE
WEST/SOUTHWEST BOTH SUPPORT HIGHEST POPS ACROSS FAR SOUTHWESTERN
PARTS OF THE CWA LATE TONIGHT AND EARLY TUESDAY.
TURNING OUR ATTENTION BACK TO THE WEST TUESDAY...CYCLOGENESIS TAKES
PLACE ACROSS THE PLAINS IN RESPONSE TO AMPLIFICATION OF UPPER TROUGH
ACROSS THE WESTERN CONUS. RESULTING STRENGTHENING IN SOUTHERLY
RETURN FLOW AND STRONG MOISTURE ADVECTION DEVELOPS INTO THE AREA
TUESDAY NIGHT...WITH ANOMALOUSLY STRONG MOISTURE TRANSPORT FOR
SEPTEMBER LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING. TAPPING OF
SOUTHWEST MONSOONAL MOISTURE AS WELL AS SOME REMNANTS OF MOISTURE
ASSOCIATED WITH HURRICANE NORBERT BRINGS PWATS OF 2+ INCHES INTO THE
AREA IN PRE-COLD FRONTAL THETA-E PLUME. THIS SUPPORTS HEAVY RAINFALL
THREAT (1.5-2.0 INCH AERIAL AMOUNTS) ACROSS NORTHERN IL EARLY
WEDNESDAY...SHIFTING INTO CENTRAL IL AND NORTHWEST INDIANA WEDNESDAY
AFTERNOON AHEAD OF COLD FRONT WHICH MOVES THROUGH DURING THE
AFTERNOON AND EVENING HOURS. IN ADDITION...THIS STRONG DYNAMIC
SYSTEM ALSO PRESENTS THE THREAT OF SEVERE WEATHER PARTICULARLY
MIDDAY WEDNESDAY AND WEDNESDAY AFTERNOON AS STRONG DEEP LAYER SHEAR
AND WEAK-MODERATE INSTABILITY COMBINE FOR SOME DEGREE OF A DAMAGING
WIND THREAT. SPC HAS NORTHWEST PART OF THE CWA IN THE DAY 2 SLIGHT
RISK...THOUGH AREA WILL BE IN LESS NOCTURNALLY FAVORED TIMING OF
BEST STORM THREAT TUESDAY. DAY 3 SLIGHT RISK ACROSS MOST OF THE CWA
WILL BE BETTER ALIGNED WITH DIURNAL CYCLE...ESPECIALLY ACROSS THE
SOUTHEAST PORTION OF THE FORECAST AREA WHERE COLD FRONT WILL BE
APPROACHING DURING THE AFTERNOON. EXTENSIVE CLOUD COVER AND PRECIP
EARLY WEDNESDAY WILL NO DOUBT PLAY A LARGE ROLE IN MODULATING
LOCATION AND EXTENT OF SEVERE THREAT...LEAVING SOME UNCERTAINTIES AT
THIS DISTANCE.
FIRST REAL TASTE OF AUTUMNAL COOL AIR SPREADS IN WEDNESDAY NIGHT AND
THURSDAY AS THE LOW PULLS AWAY FROM THE GREAT LAKES. HIGHS IN THE
60S AND LOWS IN THE UPPER 40S/50S CHARACTERIZE THE REMAINDER OF THE
FORECAST PERIOD...WITH HIGHS PERHAPS NOT GETTING ABOVE 65
FRIDAY-SATURDAY WITH A SECONDARY PUSH OF COOLER AIR. THIS SECONDARY
COLD FRONT MAY ALSO SPUR A FEW SHOWERS FRIDAY WITH MID-LEVEL SHORT
WAVE PASSING ACROSS THE AREA DURING THE DAY. SURFACE HIGH PRESSURE
RIDGE OVER THE WEEKEND SHOULD ALLOW RELATIVELY DRY CONDITIONS
DESPITE THE COOL TEMPS...THOUGH A FEW LAKE EFFECT SHOWERS WILL BE
POSSIBLE ACROSS NORTHWEST INDIANA ESPECIALLY FRIDAY NIGHT AND
SATURDAY WITH INSTABILITY INDUCED BY COOL AIR OVER MILD LAKE
WATERS.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SOUTHERLY WINDS SPORADICALLY GUSTING TO OVER 10 KT THIS
AFTERNOON.
* SLIGHT CHANCE FOR SHRA TUESDAY MORNING...WITH A CHANCE FOR TSRA
IN THE WESTERN TRACON AREA.
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE IS BEGINNING TO PULL AWAY WITH SOUTHERLY WINDS
ENCOMPASSING THE AREA. THE WIND DIRECTION AT CHICAGOLAND TAF
SITES HAS AND LIKELY WILL CONTINUE TO BE SOMEWHAT VARIABLE BETWEEN
SOUTHWEST AND SOUTHEAST. WHILE ORD AND MDW OBSERVATIONS HAVE
INDICATED A FEW GUSTS IN EXCESS OF 10 KT...BELIEVE THAT SUCH GUSTS
WILL BE INFREQUENT BASED ON THE ATMOSPHERIC PROFILE THIS
AFTERNOON. PER OBSERVATIONAL TRENDS...THE LAKE BREEZE LOOKS TO
VERY LIKELY STAY EAST OF ORD AND MDW. THE SYNOPTIC WIND WILL
LIKELY STILL OFFER ENOUGH OF A SOUTHEAST COMPONENT TO TURN THE
WINDS SLIGHTLY EAST OF SOUTH FROM TIME TO TIME THIS
AFTERNOON...BUT AGAIN SPEEDS SHOULD BE 6-10 KT MUCH OF THE TIME.
THUNDERSTORMS OVER WESTERN IA HAD DIFFICULTLY EVOLVING EASTWARD
THIS MORNING. AS AN UPPER LEVEL DISTURBANCE MOVES INTO THIS AREA
AND ADVANCED EAST...IT SHOULD HELP SHOWERS AND STORMS TO DO THE
SAME. AN UPTICK IN COVERAGE IS EXPECTED THIS EVE ACROSS EASTERN IA
AND POSSIBLY INTO NORTHWESTERN/WESTERN IL AS THE NIGHT PROGRESSES.
THE ATMOSPHERE FAVORS ANY ORGANIZED AREA OF SHOWERS AND STORMS TO
MOVE SOUTHEAST. RIGHT NOW ITS DIFFICULT TO SAY IF SHOWERS WILL
REMAIN WEST OF CHICAGOLAND SITES TUESDAY MORNING...HOWEVER THERE
IS GREATER CONFIDENCE THAT TSRA WILL STAY WEST/SOUTHWEST THROUGH
TUESDAY MORNING.
A POTENTIALLY ACTIVE AND IMPACTING PERIOD TO AVIATION WEATHER AT
AREA TAF SITES APPEARS TO BE SHAPING UP LATE TUESDAY NIGHT THROUGH
WEDNESDAY WITH A PROBABLE PERIOD OR PERIODS OF STORMS...GUSTY
SOUTHERLY WINDS...AND POTENTIALLY LOW CLOUDS WEDNESDAY MORNING.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM THAT WINDS WILL NOT BECOME SOUTHEAST AND FREQUENTLY
GREATER THAN 10 KT.
* MEDIUM IN SHRA REMAINING WEST OF THE AIRFIELDS TUESDAY MORNING.
HIGH THAT TSRA WILL REMAIN WEST OF THE AIRFIELDS TUESDAY MORNING.
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 18Z...
TUESDAY NIGHT...CHC SHRA/TSRA INCREASING OVERNIGHT. SOUTHERLY
WINDS INCREASING WITH 40 KT FLOW AROUND 1000-1500 FT.
WEDNESDAY...SHRA/TSRA LIKELY ESPECIALLY IN THE MORNING. GUSTY
SOUTHERLY WINDS...AT TIMES TO 25 KT AND POSSIBLY 30 KT. MAINLY
VFR...BUT PATCHY IFR IN STRONGER SHRA/TSRA.
THURSDAY THROUGH SUNDAY...MAINLY VFR.
MTF
&&
.MARINE...
156 PM CDT
THE MAIN FORECAST CONCERNS CENTER AROUND A SIGNIFICANT STORM SYSTEM
EXPECTED TO IMPACT THE GREAT LAKES WEDNESDAY THROUGH THURSDAY.
SOUTHERLY WINDS ARE EXPECTED TO INCREASE RAPIDLY AROUND OR SHORTLY
AFTER DAYBREAK WEDNESDAY AS A STRENGTHENING AREA OF LOW PRESSURE
MOVES FROM IOWA INTO SOUTHWESTERN WISCONSIN. SOUTHERLY GALES OF 35
TO 40 KT ARE PROBABLE BY MID TO LATE MORNING...ESPECIALLY ACROSS THE
SOUTHERN HALF TO 2/3RDS OF THE LAKE...AND THESE STRONG WINDS LOOK TO
CONTINUE THROUGH WEDNESDAY AFTERNOON. THE LOW IS THEN EXPECTED TO
SHIFT SOMEWHERE ACROSS THE NORTHERN PORTION OF THE LAKE BY WEDNESDAY
EVENING. THIS COULD RESULT IN A SHORT PERIOD OF LIGHT AND VARIABLE
WINDS ACROSS NORTHERN SECTIONS OF THE LAKE EARLY WEDNESDAY EVENING.
HOWEVER...ONCE THIS LOW SHIFTS EAST OF THE LAKE BY LATER WEDNESDAY
EVENING...A STRONG COLD FRONT WILL PUSH OVER THE LAKE...WITH A
PERIOD OF NORTHWESTERLY GALES LOOKING LIKE A DECENT BET ACROSS MOST
OF THE LAKE INTO EARLY THURSDAY.
THE WINDS WILL GRADUALLY ABATE SOME INTO THE LATER PORTION OF THE
WEEK AS HIGH PRESSURE BUILDS IN ACROSS THE PLAINS AND UPPER
MIDWEST. HOWEVER...THE NORTHERLY FETCH WILL LIKELY CONTINUE TO
PRODUCE SOME HIGHER 4 + FOOT WAVES THROUGH FRIDAY.
AS FOR HEADLINES...WE HAVE ISSUED A GALE WATCH FOR THE SOUTHERN
2/3RDS OF THE OPEN WATERS FROM 14 UTC WED THROUGH 15 UTC THURS
AND FOR THE NORTHERN PORTION OF THE LAKE FROM 03 UTC THURS THROUGH
15 UTC THURS. HOWEVER...AT THIS TIME I HAVE OPTED TO LEAVE THE
ILLINOIS AND INDIANA NEAR SHORES OUT OF THE GALE WATCH DUE TO THE
OFFSHORE COMPONENT OF THE FLOW AND THEIR PROXIMITY TO THE SURFACE LOW.
HOWEVER...GALE FORCE GUSTS ARE CERTAINLY POSSIBLE IN THE NEAR SHORES
AS WELL...AND THIS MAY NEED TO BE ADDED TO THE WATCH IN FUTURE
FORECAST UPDATES. AT THE VERY LEAST...A HIGH END SMALL CRAFT
ADVISORY WITH WINDS TO 30 KT WILL LIKELY BE NEEDED FOR THE NEAR
SHORE WATERS FOR WEDNESDAY THROUGH THE END OF THE WEEK.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
101 PM CDT Mon Sep 8 2014
.UPDATE...
ISSUED AT 1027 AM CDT MON SEP 8 2014
Only minor updates made to tweak high temperatures up a degree or
two for today. Surface ridging gradually shifting through eastern
Illinois late this morning will result in a weak south return flow
in west central and central IL today. This should allow highs to
climb around 80 degrees this afternoon. Upstream surface
observations and the 12z ILX sounding indicate there is still a lot
of dry air in the lower atmosphere, so any cloud cover should
mainly be restricted to high clouds from the MCS in Iowa.
Late tonight, some of the short range models are indicating the
development of another MCS in Iowa. The remnants of this may spill
over into west central IL toward daybreak...and possibly just west
of the I-55 corridor Tuesday morning before dissipating.
Confidence in the eastward extent of this convection is not very
high since there is quite a bit of short term model discrepancy
and due to the presence of low level dry air that will need to be
overcome.
&&
.SHORT TERM...(Today)
ISSUED AT 309 AM CDT MON SEP 8 2014
High pressure currently extending from New England to the Southern
Plains will provide another pleasant day across central Illinois
today. Despite cool early morning lows in the lower to middle 50s,
dry airmass will heat quite efficiently thanks to abundant
sunshine. With subsidence inversion lowering slightly from
yesterday, mixing will only take place up to around 900mb today.
This will result in similar high temperatures to yesterday, perhaps
a degree or two warmer in the upper 70s to around 80 degrees.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 309 AM CDT MON SEP 8 2014
Short-wave trough evident on 07z/2am water vapor imagery over
eastern South Dakota will track eastward tonight, triggering a
cluster of showers and thunderstorms along the nose of a 30-35kt LLJ
oriented into northern Iowa. This convection will track E/SE toward
Illinois, but will encounter an unfavorably dry/stable airmass east
of the Mississippi River. As a result, am expecting a distinct
diminishing trend as storms push into west-central Illinois late
tonight into Tuesday morning. Will continue with chance PoPs across
the Illinois River Valley after midnight, with dry conditions
expected through the entire night further east across east-central
and southeast Illinois. Diurnal weakening trend will result in
complete dissipation of thunderstorm cluster Tuesday morning,
although widely scattered showers/thunder could re-develop along
outflow boundary during the afternoon. As such, will carry low
chance PoPs along/west of I-55, with dry weather further east. Will
be a warm day as well, with high temperatures ranging from around 80
degrees northwest of the Illinois River where cloud debris will hold
readings down a bit, to the middle 80s along/south of I-70.
Main weather story is still on target for Tuesday night through
Wednesday night, as a vigorous upper-level trough digs southeastward
out of the Northern Rockies and an unseasonably strong surface low
develops over western Kansas on Tuesday. Models are in good
agreement that the low will deepen to around 992mb as it tracks to
Lake Superior by Wednesday evening. Ahead of the low, an increasing
W/SW LLJ will bring copious amounts of moisture into central
Illinois Tuesday night into Wednesday, with all model solutions
showing precipitable water values climbing to around 2.25. Trailing
cold front is expected to push into the KILX CWA on Wednesday,
accompanied by widespread showers and thunderstorms. Severe weather
will be possible Wednesday afternoon and evening as the front
progresses through the region. Main question will be degree of
destabilization, as models are indicating dew points in the lower 70s
and resulting CAPE values of 1500 to 2500J/kg. If this level of
instability is realized, storms will quickly organize along/ahead of
the front thanks to 0-6km bulk shear values increasing to between 30
and 40kt. Primary severe weather threats will be damaging wind
gusts and high rainfall rates potentially leading to localized flash
flooding. Have increased PoPs to categorical across the NW CWA late
Tuesday night and across the board on Wednesday.
Once front sinks into the Ohio River Valley, a cooler/drier airmass
will arrive on Thursday. Due to strong CAA, high temperatures will
drop into the upper 60s and lower 70s. Models have come into better
agreement concerning the timing of the trailing 500mb trough axis,
with all solutions taking it across central Illinois on Friday.
Despite dry airmass, strong upper dynamics and steep lapse rates
will be enough to trigger clouds and perhaps a few light showers on
Friday. After that, cool and dry weather will be the rule over the
weekend, with highs mainly in the 60s and overnight lows dropping
into the 40s.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 100 PM CDT MON SEP 8 2014
VFR conditions can generally be expected the next 24 hours in
central and eastern IL. A surface high pressure ridge will remain
over eastern IL into this evening with a southerly return flow
developing in central IL. However, the biggest question will be
how much return flow of low level moisture occurs, especially west
of I-55. Most of the shorter range models are depicting the
development of another MCS in Iowa overnight. However, they differ
on where the remnants may track. The HRRR seems to be too far
north with its rainfall, while the NAM and RAP keep the bulk of
the thunderstorms in SE Iowa and west central IL closer to the
lower level theta-e ridge.
With the best low level moisture advection/moisture transport
expected to be near the MS River and the forecast of Corfidi
vectors to be pointing toward the southeast, will only put a
mention of VCTS in the forecast for KPIA, with the possibility of
a VCSH along I-55 from KBMI-KSPI Tuesday morning after daybreak.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MILLER
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS JACKSON KY
259 PM EDT MON SEP 8 2014
.UPDATE...
ISSUED AT 1208 PM EDT MON SEP 8 2014
FOG HAS FINALLY LIFTED. STRATUS DECK OVER PORTIONS OF THE AREA WILL
CONTINUE TO RISE AND BREAK UP FOR GENERALLY PARTLY CLOUDY AFTERNOON
SKIES. STILL CAN NOT RULE OUT SOME ISOLD TO SCT CONVECTION THIS
AFTERNOON...THOUGH WITH TIME THOUGHTS ARE LEANING INCREASINGLY
TOWARDS MORE ISOLD COVERAGE AND MAINLY IN OUR SOUTH AND FAR EAST.
UPDATE ISSUED AT 1018 AM EDT MON SEP 8 2014
FOR THIS MORNINGS UPDATE BROUGHT GRIDS IN LINE WITH HOURLY OBS.
STUBBORN FOG AND LOW STRATUS IS LINGERING ACROSS THE AREA THIS
MORNING...MAINLY DUE TO NORTHEAST WINDS ACROSS MUCH OF THE CWA WHICH
DO TEND TO KEEP LOW STRATUS IN PLACE. HOWEVER STILL EXPECT A GRADUAL
LIFTING AND EROSION OF THE FOG AND STRATUS ONCE EFFECTS OF SUN ARE
ABLE TO BURN THROUGH TO THE SFC. A WEAK SOUTHEASTERN DOWN SLOPE FLOW
APPEARS TO BE KEEPING THE FOG AND STRATUS AT BAY ACROSS OUR HIGHER
TERRAIN IN THE SOUTHEAST.
MID LEVEL SHORT WAVE CONTINUES TO ROLL UP INTO THE MID OHIO VALLEY
THIS MORNING. THIS FEATURE IS FAIRLY VISIBLE IN WATER VAPOR IMAGES.
WHILE CAN NOT TOTALLY RULE OUT SOME SHOWER AND THUNDERSTORM ACTIVITY
THROUGH THE DAY CONFIDENCE IS WANING CONSIDERABLY. THE RAP...AND TO A
LESSER EXTENT GFS FCST SOUNDINGS ARE SHOWING A WEAK CAP ACROSS MUCH
OF THE AREA. THIS IS SOMEWHAT IN LINE WITH ILN/OHX MORNING SOUNDINGS
THOUGH BEING GENERALLY OUTSIDE OF THE INFLUENCE OF THE SHORTWAVE
THEY MAY NOT BE A GOOD REPRESENTATION OF THE PROFILE ACROSS OUR AREA.
DISCOUNTED THE NAM/S SOUNDING AS IN TYPICAL FASHION IT GREATLY
OVERDOES BOUNDARY LAYER MOISTURE AND CONSEQUENTLY BOUNDARY LAYER
INSTABILITY AND SOUNDING PARAMETERS. THE HRRR HAS TRENDED TOWARDS A
BIT LESS COVERAGE IN ACTIVITY AS WELL...AND INITIATES A BIT LATER IN
THE DAY THAN PREVIOUS RUNS. DID DELAY DEVELOPMENT OF ACTIVITY UNTIL
LATE MORNING/EARLY AFTERNOON BUT IN GENERAL KEPT INHERITED ISOLD AND
SCT POPS FOR THE AFTERNOON TIME FRAME.
UPDATE ISSUED AT 730 AM EDT MON SEP 8 2014
TWEAKED THE GRIDS A BIT EARLY THIS MORNING TO FINE TUNE THE SKY COVER
AND T/TD PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE
NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 345 AM EDT MON SEP 8 2014
07Z SFC ANALYSIS SHOWS COOL AND DRY HIGH PRESSURE SPRAWLED OUT FROM
THE OHIO VALLEY THROUGH THE NEW ENGLAND STATES. GENERAL LOW PRESSURE
IS FOUND OVER THE DEEP SOUTH AND ALONG THE SOUTHEAST COAST. NOT FAR
FROM EAST KENTUCKY IS A STALLED FRONTAL BOUNDARY LURKING JUST TO THE
SOUTH. THIS HAS HELPED TO PREVENT THE DRY COMPONENT OF THE HIGH
PRESSURE FROM MAKING IT THROUGH ALL OF THE STATE AS DEW POINTS ALONG
THE TENNESSEE BORDER ARE IN THE LOW AND MID 60S WHILE MID AND UPPER
50S EXIST TO THE NORTH. THESE NORTHERN SPOTS ARE ALSO ENJOYING
TEMPERATURES DOWN INTO THE MIDDLE AND UPPER 50S...PARTICULARLY IN THE
VALLEYS WHERE MOSTLY CLEAR SKIES HAVE ALLOWED FOR DECENT RADIATIONAL
COOLING BELOW THE THERMAL INVERSION. MEANWHILE...RIDGES AND LOCATIONS
TO THE SOUTH WITH HIGHER DEW POINTS ARE SEEING TEMPERATURES A FEW
DEGREES MORE. A COUPLE LARGE PATCHES OF LOW CLOUDS ARE AFFECTING
SOUTHEAST KENTUCKY EARLY THIS MORNING HELPING TO DISRUPT THE FOG
FORMATION...THOUGH THERE WILL UNDOUBTEDLY BE PATCHY FOG...LOCALLY
DENSE...IN MANY VALLEY LOCATIONS GENERALLY CORRESPONDING TO THE
CLEAR SPOTS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH ANOTHER POCKET OF ENERGY
ROLLING EAST THROUGH GENERALLY FLAT FLOW TODAY...HELPING TO LOWER
HEIGHTS LOCALLY AND BRING SOME EXTRA LIFT TO THE AREA. THIS MOVES
THROUGH BY EVENING WITH CONTINUED RELATIVELY FAST AND NEARLY ZONAL
FLOW INTO THE DAY TUESDAY. LATE IN THE SHORT TERM PORTION OF THE
FORECAST HEIGHTS WILL CLIMB A NOTCH AHEAD OF A LARGE AND DEEPENING
TROUGH OVER THE ROCKY MOUNTAIN AND HIGH PLAINS STATES. WITH THE MODEL
SIMILARITIES HAVE GONE MAINLY WITH A BLEND OF THE HRRR AND NAM12 FOR
WX SPECIFICS DURING THE FIRST 12-18 HOURS AND THEN THE 00Z
ECMWF/NAM12 THROUGH TUESDAY.
SENSIBLE WEATHER WILL FEATURE A CONTINUED COOL AND DRY DAY ACROSS THE
FAR NORTHWEST PARTS OF THE AREA WHILE TO THE SOUTHEAST THERE WILL BE
MUCH MORE CLOUD COVER ALONG WITH A THREAT FOR SHOWERS THROUGH
THE MORNING. BY MIDDAY THUNDER CHANCES WILL PICK UP OWING TO BUILDING
INSTABILITY AND THE NEARBY FRONT BEING ACTED UPON BY THE PASSING MID
LEVEL SHORT WAVE. THE PCPN THREAT AND SOME OF THE CLOUD COVER WILL
RETREAT TO THE EAST LATER TONIGHT WITH ANOTHER NIGHT OF MINOR RIDGE
TO VALLEY TEMPERATURE DIFFERENCES AMIDST A NW TO SE STRIATION IN
DEW POINTS. DUE TO THIS ANTICIPATE PATCHY VALLEY FOG AFTER MIDNIGHT
FOR MOST LOCATIONS...PARTICULARLY ONES THAT MANAGE TO SEE ANY RAIN
DURING THE DAY AND EVENING. TUESDAY WILL BE QUIET AND DRY...BUT A TAD
WARMER WHILE THE DEVELOPING LOW TO THE EAST STARTS TO LIFT NORTH
ALONG THE SOUTH EAST ATLANTIC SEABOARD.
STARTED WITH THE CONSSHORT FOR T...TD...AND WINDS...THROUGH THE
FIRST 24 HOURS FOLLOWED BY THE SUPERBLEND UNTIL 00Z WED. PER
USUAL...MADE MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS
TONIGHT. AS FOR POPS...ENDED UP CLOSER TO THE LOWER MAV GUIDANCE
TODAY AND SIMILAR TO A BLEND OF THE RATHER LOW NUMBERS THEREAFTER
THROUGH THE REMAINDER OF THE SHORT TERM FORECAST.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM EDT MON SEP 8 2014
THE MODELS REMAIN IN GOOD AGREEMENT IN THE LONG TERM...WITH A LARGE
RIDGE OF HIGH PRESSURE ALOFT INFLUENCING THE WEATHER OF EASTERN
KENTUCKY TO BEGIN THE PERIOD. DRY WEATHER SHOULD BE ON TAP TUESDAY
NIGHT INTO EARLY WEDNESDAY AFTERNOON AS HIGH PRESSURE REMAINS IN
CONTROL. HOWEVER...THIS UPPER RIDGE WILL BE DISPLACED AS DEEP AREA
OF LOW PRESSURE...BOTH ALOFT AND AT THE SURFACE...COMES TOGETHER
OVER THE NORTHERN PLAINS AND BEGINS TO PUSH ACROSS THE NORTHERN
MISSISSIPPI VALLEY ON WEDNESDAY. THE SURFACE COLD FRONT ASSOCIATED
WITH THIS POTENT SYSTEM WILL BRING UNSETTLED WEATHER TO THE AREA
WEDNESDAY NIGHT AND THURSDAY. THE PRIMARY CONCERN WITH THIS WEATHER
SYSTEM WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. THE MODELS
HAVE THE FRONT SLOWING DOWN AND NEARLY STALLING ACROSS OUR AREA ON
THURSDAY. SHOWERS AND STORMS ARE EXPECTED TO FIRE ALL ALONG THE
BOUNDARY AS LARGE AMOUNTS OF WARM MOIST AIR OFF THE GULF OF MEXICO
IS CARRIED NORTHWARD INTO THE BOUNDARY ON SOUTHERLY WINDS. THE BEST
CHANCE FOR RAIN LOOKS TO BE FROM LATE THURSDAY MORNING THROUGH LATE
THURSDAY AFTERNOON WHEN MOISTURE FLOW INTO THE FRONTAL ZONE IS AT
ITS PEAK. THERE WILL ALSO BE THE POTENTIAL FOR A FEW STRONG
THUNDERSTORMS ON THURSDAY AS THE FRONT MOVES THROUGH AS THERE WILL
BE STRONG DYNAMICS ASSOCIATED WITH THE BOUNDARY AND ITS PARENT UPPER
LEVEL SYSTEM. THUNDERSTORMS SHOULD THEN GIVE WAY TO RAIN SHOWER
BEHIND THE FRONT THURSDAY NIGHT AS THE COOLER AIR MOVES IN BEHIND
THE FRONT. THE FRONT IS EXPECTED TO EVENTUALLY CLEAR THE AREA LATE
THURSDAY NIGHT INTO EARLY FRIDAY MORNING...AS A LARGE RIDGE OF
CANADIAN HIGH PRESSURE PUSHES IT OFF TO OUR EAST. THIS AREA OF HIGH
PRESSURE WILL BRING A SIGNIFICANT PATTERN CHANGE TO THE MAJORITY OF
THE CONUS EAST OF THE ROCKY MOUNTAINS FROM FRIDAY ONWARD.
AFTER SLIGHTLY ABOVE NORMAL TEMPERATURES TUESDAY NIGHT AND
WEDNESDAY...A PERIOD OF UNSEASONABLE COOLING WILL BE OCCURRING.
HIGHS ON WEDNESDAY ARE EXPECTED TO TOP OUT IN THE MID TO UPPER 80S
AS SOUTHERLY WINDS BRING WARM MOIST AIR FROM THE GULF OF MEXICO INTO
THE REGION. ONCE THE FRONT ARRIVES ON THURSDAY...WIDESPREAD CLOUD
COVER AND PRECIPITATION WILL KEEP TEMPERATURES WELL BELOW
NORMAL...WITH HIGHS ONLY CLIMBING TO AROUND 80 BY THURSDAY
AFTERNOON. ONCE THE BOUNDARY HAS CLEARED THE AREA LATE THURSDAY
NIGHT...AN INVASION OF COOL AN DRY CANADIAN AIR WILL BEGIN TO OCCUR.
WITH WINDS SHIFTING TO THE NORTH BEHIND THE FRONT...TEMPERATURES
WILL BE HARD PRESSED TO CLIMB INTO THE MID 70S ON FRIDAY. THE COOL
WEATHER WILL THEN PERSIST THROUGH THE WEEKEND AS THE RIDGE OF HIGH
PRESSURE BECOMES MORE FIRMLY ESTABLISHED. HIGH TEMPERATURES ON
SATURDAY ARE EXPECTED TO ONLY CLIMB TO AROUND 70 WITH HIGHS ON
SUNDAY ONLY WARMING INTO THE LOW 70S. OVERNIGHT LOWS IN THE 50S ARE
EXPECTED AREA WIDE FRIDAY AND SATURDAY NIGHT AS THE COOL CANADIAN
AIR POURS INTO THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 259 PM EDT MON SEP 8 2014
PESKY LOW STRATUS AND FOG FINALLY LIFTED BY MID DAY. STILL SEEING
SOME INTERMITTENT MVFR CIGS AT A FEW PLACES BUT DAYTIME HEATING
SHOULD CONTINUE TO WORK ITS MAGIC LIFTING BASES JUST A BIT MORE
THROUGH THE AFTERNOON. RADAR DOES SHOW SOME SHOWER ACTIVITY KICKING
OFF. BUT DEVELOPMENT HAS BEEN SLOW. HIGH RES MODELS SUGGEST THAT A
CLUSTER OF STORMS MAY DEVELOP AND MOVE NORTHWARD OUT OF TN LATE THIS
AFTERNOON...AFFECTING MAINLY OUR SOUTHWESTERN TERMINALS. WILL WATCH
CLOSELY BUT CURRENT THINKING IS THAT ACTIVITY WILL GENERALLY LEAN
TOWARDS BEING MORE ISOLD OVER THOSE AREAS AND MORE SCATTERED IN
NATURE OVER OUR FAR SOUTH AND EAST. EXPECT FOG TO REDEVELOP ACROSS
THE AREA AGAIN TONIGHT...BUT NOT QUITE AS WIDESPREAD AND DENSE AS
THIS MORNING. WINDS WILL BE LIGHT THROUGH THE FORECAST PERIOD...
GENERALLY FROM THE WEST SOUTHWEST DURING DAYLIGHT HOURS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...RAY
AREA FORECAST DISCUSSION
NWS JACKSON KY
1208 PM EDT MON SEP 8 2014
.UPDATE...
ISSUED AT 1208 PM EDT MON SEP 8 2014
FOG HAS FINALLY LIFTED. STRATUS DECK OVER PORTIONS OF THE AREA WILL
CONTINUE TO RISE AND BREAK UP FOR GENERALLY PARTLY CLOUDY AFTERNOON
SKIES. STILL CAN NOT RULE OUT SOME ISOLD TO SCT CONVECTION THIS
AFTERNOON...THOUGH WITH TIME THOUGHTS ARE LEANING INCREASINGLY
TOWARDS MORE ISOLD COVERAGE AND MAINLY IN OUR SOUTH AND FAR EAST.
UPDATE ISSUED AT 1018 AM EDT MON SEP 8 2014
FOR THIS MORNINGS UPDATE BROUGHT GRIDS IN LINE WITH HOURLY OBS.
STUBBORN FOG AND LOW STRATUS IS LINGERING ACROSS THE AREA THIS
MORNING...MAINLY DUE TO NORTHEAST WINDS ACROSS MUCH OF THE CWA WHICH
DO TEND TO KEEP LOW STRATUS IN PLACE. HOWEVER STILL EXPECT A GRADUAL
LIFTING AND EROSION OF THE FOG AND STRATUS ONCE EFFECTS OF SUN ARE
ABLE TO BURN THROUGH TO THE SFC. A WEAK SOUTHEASTERN DOWN SLOPE FLOW
APPEARS TO BE KEEPING THE FOG AND STRATUS AT BAY ACROSS OUR HIGHER
TERRAIN IN THE SOUTHEAST.
MID LEVEL SHORT WAVE CONTINUES TO ROLL UP INTO THE MID OHIO VALLEY
THIS MORNING. THIS FEATURE IS FAIRLY VISIBLE IN WATER VAPOR IMAGES.
WHILE CAN NOT TOTALLY RULE OUT SOME SHOWER AND THUNDERSTORM ACTIVITY
THROUGH THE DAY CONFIDENCE IS WANING CONSIDERABLY. THE RAP...AND TO A
LESSER EXTENT GFS FCST SOUNDINGS ARE SHOWING A WEAK CAP ACROSS MUCH
OF THE AREA. THIS IS SOMEWHAT IN LINE WITH ILN/OHX MORNING SOUNDINGS
THOUGH BEING GENERALLY OUTSIDE OF THE INFLUENCE OF THE SHORTWAVE
THEY MAY NOT BE A GOOD REPRESENTATION OF THE PROFILE ACROSS OUR AREA.
DISCOUNTED THE NAM/S SOUNDING AS IN TYPICAL FASHION IT GREATLY
OVERDOES BOUNDARY LAYER MOISTURE AND CONSEQUENTLY BOUNDARY LAYER
INSTABILITY AND SOUNDING PARAMETERS. THE HRRR HAS TRENDED TOWARDS A
BIT LESS COVERAGE IN ACTIVITY AS WELL...AND INITIATES A BIT LATER IN
THE DAY THAN PREVIOUS RUNS. DID DELAY DEVELOPMENT OF ACTIVITY UNTIL
LATE MORNING/EARLY AFTERNOON BUT IN GENERAL KEPT INHERITED ISOLD AND
SCT POPS FOR THE AFTERNOON TIME FRAME.
UPDATE ISSUED AT 730 AM EDT MON SEP 8 2014
TWEAKED THE GRIDS A BIT EARLY THIS MORNING TO FINE TUNE THE SKY COVER
AND T/TD PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE
NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 345 AM EDT MON SEP 8 2014
07Z SFC ANALYSIS SHOWS COOL AND DRY HIGH PRESSURE SPRAWLED OUT FROM
THE OHIO VALLEY THROUGH THE NEW ENGLAND STATES. GENERAL LOW PRESSURE
IS FOUND OVER THE DEEP SOUTH AND ALONG THE SOUTHEAST COAST. NOT FAR
FROM EAST KENTUCKY IS A STALLED FRONTAL BOUNDARY LURKING JUST TO THE
SOUTH. THIS HAS HELPED TO PREVENT THE DRY COMPONENT OF THE HIGH
PRESSURE FROM MAKING IT THROUGH ALL OF THE STATE AS DEWPOINTS ALONG
THE TENNESSEE BORDER ARE IN THE LOW AND MID 60S WHILE MID AND UPPER
50S EXIST TO THE NORTH. THESE NORTHERN SPOTS ARE ALSO ENJOYING
TEMPERATURES DOWN INTO THE MIDDLE AND UPPER 50S...PARTICULARLY IN THE
VALLEYS WHERE MOSTLY CLEAR SKIES HAVE ALLOWED FOR DECENT RADIATIONAL
COOLING BELOW THE THERMAL INVERSION. MEANWHILE...RIDGES AND LOCATIONS
TO THE SOUTH WITH HIGHER DEWPOINTS ARE SEEING TEMPERATURES A FEW
DEGREES MORE. A COUPLE LARGE PATCHES OF LOW CLOUDS ARE AFFECTING
SOUTHEAST KENTUCKY EARLY THIS MORNING HELPING TO DISRUPT THE FOG
FORMATION...THOUGH THERE WILL UNDOUBTEDLY BE PATCHY FOG...LOCALLY
DENSE...IN MANY VALLEY LOCATIONS GENERALLY CORRESPONDING TO THE
CLEAR SPOTS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH ANOTHER POCKET OF ENERGY
ROLLING EAST THROUGH GENERALLY FLAT FLOW TODAY...HELPING TO LOWER
HEIGHTS LOCALLY AND BRING SOME EXTRA LIFT TO THE AREA. THIS MOVES
THROUGH BY EVENING WITH CONTINUED RELATIVELY FAST AND NEARLY ZONAL
FLOW INTO THE DAY TUESDAY. LATE IN THE SHORT TERM PORTION OF THE
FORECAST HEIGHTS WILL CLIMB A NOTCH AHEAD OF A LARGE AND DEEPENING
TROUGH OVER THE ROCKY MOUNTAIN AND HIGH PLAINS STATES. WITH THE MODEL
SIMILARITIES HAVE GONE MAINLY WITH A BLEND OF THE HRRR AND NAM12 FOR
WX SPECIFICS DURING THE FIRST 12-18 HOURS AND THEN THE 00Z
ECMWF/NAM12 THROUGH TUESDAY.
SENSIBLE WEATHER WILL FEATURE A CONTINUED COOL AND DRY DAY ACROSS THE
FAR NORTHWEST PARTS OF THE AREA WHILE TO THE SOUTHEAST THERE WILL BE
MUCH MORE CLOUD COVER ALONG WITH A THREAT FOR SHOWERS THROUGH
THE MORNING. BY MIDDAY THUNDER CHANCES WILL PICK UP OWING TO BUILDING
INSTABILITY AND THE NEARBY FRONT BEING ACTED UPON BY THE PASSING MID
LEVEL SHORT WAVE. THE PCPN THREAT AND SOME OF THE CLOUD COVER WILL
RETREAT TO THE EAST LATER TONIGHT WITH ANOTHER NIGHT OF MINOR RIDGE
TO VALLEY TEMPERATURE DIFFERENCES AMIDST A NW TO SE STRIATION IN
DEWPOINTS. DUE TO THIS ANTICIPATE PATCHY VALLEY FOG AFTER MIDNIGHT
FOR MOST LOCATIONS...PARTICULARLY ONES THAT MANAGE TO SEE ANY RAIN
DURING THE DAY AND EVENING. TUESDAY WILL BE QUIET AND DRY...BUT A TAD
WARMER WHILE THE DEVELOPING LOW TO THE EAST STARTS TO LIFT NORTH
ALONG THE SOUTH EAST ATLANTIC SEABOARD.
STARTED WITH THE CONSSHORT FOR T...TD...AND WINDS...THROUGH THE
FIRST 24 HOURS FOLLOWED BY THE SUPERBLEND UNTIL 00Z WED. PER
USUAL...MADE MINOR ADJUSTMENTS FOR TERRAIN DIFFERENCES WITH TEMPS
TONIGHT. AS FOR POPS...ENDED UP CLOSER TO THE LOWER MAV GUIDANCE
TODAY AND SIMILAR TO A BLEND OF THE RATHER LOW NUMBERS THEREAFTER
THROUGH THE REMAINDER OF THE SHORT TERM FORECAST.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM EDT MON SEP 8 2014
THE MODELS REMAIN IN GOOD AGREEMENT IN THE LONG TERM...WITH A LARGE
RIDGE OF HIGH PRESSURE ALOFT INFLUENCING THE WEATHER OF EASTERN
KENTUCKY TO BEGIN THE PERIOD. DRY WEATHER SHOULD BE ON TAP TUESDAY
NIGHT INTO EARLY WEDNESDAY AFTERNOON AS HIGH PRESSURE REMAINS IN
CONTROL. HOWEVER...THIS UPPER RIDGE WILL BE DISPLACED AS DEEP AREA
OF LOW PRESSURE...BOTH ALOFT AND AT THE SURFACE...COMES TOGETHER
OVER THE NORTHERN PLAINS AND BEGINS TO PUSH ACROSS THE NORTHERN
MISSISSIPPI VALLEY ON WEDNESDAY. THE SURFACE COLD FRONT ASSOCIATED
WITH THIS POTENT SYSTEM WILL BRING UNSETTLED WEATHER TO THE AREA
WEDNESDAY NIGHT AND THURSDAY. THE PRIMARY CONCERN WITH THIS WEATHER
SYSTEM WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. THE MODELS
HAVE THE FRONT SLOWING DOWN AND NEARLY STALLING ACROSS OUR AREA ON
THURSDAY. SHOWERS AND STORMS ARE EXPECTED TO FIRE ALL ALONG THE
BOUNDARY AS LARGE AMOUNTS OF WARM MOIST AIR OFF THE GULF OF MEXICO
IS CARRIED NORTHWARD INTO THE BOUNDARY ON SOUTHERLY WINDS. THE BEST
CHANCE FOR RAIN LOOKS TO BE FROM LATE THURSDAY MORNING THROUGH LATE
THURSDAY AFTERNOON WHEN MOISTURE FLOW INTO THE FRONTAL ZONE IS AT
ITS PEAK. THERE WILL ALSO BE THE POTENTIAL FOR A FEW STRONG
THUNDERSTORMS ON THURSDAY AS THE FRONT MOVES THROUGH AS THERE WILL
BE STRONG DYNAMICS ASSOCIATED WITH THE BOUNDARY AND ITS PARENT UPPER
LEVEL SYSTEM. THUNDERSTORMS SHOULD THEN GIVE WAY TO RAIN SHOWER
BEHIND THE FRONT THURSDAY NIGHT AS THE COOLER AIR MOVES IN BEHIND
THE FRONT. THE FRONT IS EXPECTED TO EVENTUALLY CLEAR THE AREA LATE
THURSDAY NIGHT INTO EARLY FRIDAY MORNING...AS A LARGE RIDGE OF
CANADIAN HIGH PRESSURE PUSHES IT OFF TO OUR EAST. THIS AREA OF HIGH
PRESSURE WILL BRING A SIGNIFICANT PATTERN CHANGE TO THE MAJORITY OF
THE CONUS EAST OF THE ROCKY MOUNTAINS FROM FRIDAY ONWARD.
AFTER SLIGHTLY ABOVE NORMAL TEMPERATURES TUESDAY NIGHT AND
WEDNESDAY...A PERIOD OF UNSEASONABLE COOLING WILL BE OCCURRING.
HIGHS ON WEDNESDAY ARE EXPECTED TO TOP OUT IN THE MID TO UPPER 80S
AS SOUTHERLY WINDS BRING WARM MOIST AIR FROM THE GULF OF MEXICO INTO
THE REGION. ONCE THE FRONT ARRIVES ON THURSDAY...WIDESPREAD CLOUD
COVER AND PRECIPITATION WILL KEEP TEMPERATURES WELL BELOW
NORMAL...WITH HIGHS ONLY CLIMBING TO AROUND 80 BY THURSDAY
AFTERNOON. ONCE THE BOUNDARY HAS CLEARED THE AREA LATE THURSDAY
NIGHT...AN INVASION OF COOL AN DRY CANADIAN AIR WILL BEGIN TO OCCUR.
WITH WINDS SHIFTING TO THE NORTH BEHIND THE FRONT...TEMPERATURES
WILL BE HARD PRESSED TO CLIMB INTO THE MID 70S ON FRIDAY. THE COOL
WEATHER WILL THEN PERSIST THROUGH THE WEEKEND AS THE RIDGE OF HIGH
PRESSURE BECOMES MORE FIRMLY ESTABLISHED. HIGH TEMPERATURES ON
SATURDAY ARE EXPECTED TO ONLY CLIMB TO AROUND 70 WITH HIGHS ON
SUNDAY ONLY WARMING INTO THE LOW 70S. OVERNIGHT LOWS IN THE 50S ARE
EXPECTED AREA WIDE FRIDAY AND SATURDAY NIGHT AS THE COOL CANADIAN
AIR POURS INTO THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 750 AM EDT MON SEP 8 2014
A LOW CLOUD DECK REMAINS IN PLACE OVER MUCH OF EAST KENTUCKY WITH
STILL SOME WESTWARD EXPANSION NOTED IN THE SATELLITE TRENDS. THESE
CLOUDS ARE GENERALLY IN THE MVFR RANGE FOR CIGS...BUT THERE ARE AREAS
OF MUCH LOWER CIGS DOWN TO LIFR IN THE SOUTH ALONG WITH LOW VIS FROM
FOG. ISOLATED TO SCATTERED RAIN SHOWERS ARE EXPECTED TO REDEVELOP...
MAINLY EAST OF JKL...BY MID MORNING AND PERSISTING INTO THE AFTERNOON.
AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT AS WELL THROUGH THE
EARLY EVENING HOURS. HAVE A VCTS FOR THIS IN THE ALL THE TAFS EXCEPT
SYM. WINDS THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE ACROSS THE
FORECAST AREA.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
434 PM EDT MON SEP 8 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 402 PM EDT MON SEP 8 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS
THE NRN CONUS AND SRN CANADA. A SHORTWAVE TROUGH OVER WI AND
ASSOCIATED 700-300 MB QVECTOR CONV SUPPORTED SOME VERY LIGHT RAIN
SHOWERS OR SPINKLES OVER NRN WI INTO FAR WRN UPPER MI. WITH THE
FORCING MAINLY IN THE 500-300 MB LAYER AND RELATIVELY DRY LOW LEVELS
JUST MID LEVEL CLOUDS/CIGS WERE REPORTED WITH MOST STATIONS NOT EVEN
REPORTING ANY MEASURABLE AMOUNTS. OTHERWISE...PARLTY CLOUDY SKIES
WITH GUSTY SOUTH WINDS OF 15 TO 25 MPH PREVAILED OVER THE REST OF
THE CWA.
TONIGHT...EXPECT THE -SHRA/SPRINKLES OVER SW UPPER MI TO SLOWLY
SLIDE TO THE EAST THIS EVENING AS THE SHRTWV DEPARTS. THE LEFTOVER
MID CLOUDS SHOULD ALSO THIN OUT OVERNIGHT AS QVECTOR DIV SPREADS
INTO THE AREA. HOWEVER...WITH INCREASING SW FLOW 925-700 MB THETA-E
ADVECTION ADDITIONAL CLOUDS MAY SPREAD INTO THE WEST HALF LATE. THE
SRLY FLOW WILL KEEP MIN READINGS IN THE MID 50S INLAND TO AROUND 60
IN DOWNSLOPE LOCATIONS NEAR LAKE SUPERIOR.
TUESDAY...THE MODELS SUGGEST THAT A FRONTAL BOUNDARY WILL SLOWLY
DROP THROUGH WRN LAKE SUPERIOR AND AIDED BY THE LAKE BREEZE INTO THE
NW CWA BY AFTERNOON. THE COMBINATION OF THE APPROACHING FRONTAL
BOUNDARY...MLCAPE VALUES INTO THE 1K-2K RANGE...RELATIVELY WEAK
CAPPING AND THE POTENTIAL A WEAK SHORTWAVE BRUSHING THE AREA MAY
PRODUCE SOME ISOLD/SCT SHRA/TSRA BY MID TO LATE AFTERNOON OVER THE
WEST HALF. SINCE THE STRONGEST FORCING IS EXPECTED TO REMAIN NW OF
THE CWA...ONLY LOWER END CHANCE POPS WERE INCLUDED.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 431 PM EDT MON SEP 8 2014
THE MAIN ISSUES THIS FORECAST PERIOD WILL BE THE FLOODING POTENTIAL
TUESDAY NIGHT THROUGH WEDNESDAY MORNING...GALES ON LAKE SUPERIOR
WEDNESDAY INTO WEDNESDAY NIGHT AND COLDER THAN NORMAL TEMPERATURES
MOVING IN THURSDAY NIGHT THROUGH SATURDAY.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...LOW PRESSURE WILL INTENSIFY
OVER THE CENTRAL PLAINS AS IT LIFTS NORTHEASTWARD TO WESTERN IOWA
LATE TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING AT OR AROUND 1000MB.
AT THE SAME TIME...AN UPPER LEVEL 500MB TROUGH AXIS SLIDES ACROSS
THE ROCKIES INTO THE PLAINS STATES. MODELS ARE IN FAIRLY GOOD
AGREEMENT...HOWEVER...THE 12Z NAM IS A BIT OF AN OUTLIER...TAKING
THE LOW FARTHER NORTH AND WEST THAN THE OTHER MODELS. SHOWERS AND
THUNDERSTORMS WILL DEVELOP AHEAD OF THE LOW PRESSURE SYSTEM ON
INCREASED MOISTURE UPGLIDE AS SHOWN ON THE 300K ISOSURFACE ALONG
WITH INCREASING MOISTURE SHOWN BY PLOTTING 1000-500 RH. THE BEST
CHANCE OF CONVECTION WOULD BE TUESDAY EVENING WITH INSTABILITY
LINGERING ON THE WARM SIDE OF THE LOW. THE LOW WILL CONTINUE
NORTHEASTWARD TO JUST SOUTH OF JAMES BAY WHILE FURTHER STRENGTHENING
TO AROUND 990MB AS THE UPPER LEVEL TROUGH SLIDES INTO THE UPPER
MISSISSIPPI VALLEY. AT THIS POINT...THE HEAVY RAINFALL POTENTIAL
WOULD BE GREATEST LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING...AS
DEEP LAYER MOISTURE WOULD BE IN PLACE AT THE SAME TIME ISENTROPIC
UPGLIDE IS MAXIMIZED AND DEEP LAYER FORCING IS MAXIMIZED AS A FAIRLY
STRONG 700MB FGEN BAND WRAPS THROUGH THE AREA. ADDITIONALLY...THE
AREA WILL LIE IN THE LEFT EXIT REGION OF A JET MAX TO THE SOUTH AND
PARTIALLY IN THE INFLUENCE OF A RIGHT ENTRANCE REGION OF A JET MAX
TO THE NORTH. ALSO IN SUPPORT OF HEAVY RAINFALL TUESDAY NIGHT
THROUGH WEDNESDAY MORNING WILL BE PWAT VALUES CONTINUING TO BE
PROGGED AT 1.5 TO 2 INCHES ON STRONG SOUTHERLY MOISTURE TRANSPORT
INTO THE REGION. RAINFALL WILL CONTINUE THROUGH WEDNESDAY
NIGHT...HOWEVER...OVERALL INTENSITY IS EXPECTED TO DECREASE AS THE
AFOREMENTIONED HEAVY RAINFALL FEATURES SHIFT OUT OF THE AREA AND
MAINLY WRAP AROUND PRECIP LINGERS OVER GENERALLY THE WESTERN U.P. AS
A DRY SLOT IS PROGGED TO WEDGE INTO THE CENTRAL AND EASTERN
AREAS...ALLOWING FOR MAINLY DRIZZLE.
HEAVY RAINFALL POTENTIAL INCLUDING AREAL FLOOD WATCH...WITH THE DEEP
MOISTURE AND LIFT EXPECTED ACROSS THE AREA...RAINFALL TOTALS WILL
LIKELY EXCEED 2 INCHES WITH UP TO 3 INCHES POSSIBLE ACROSS PORTIONS
OF THE CENTRAL AND WESTERN UPPER PENINSULA. MOST OF THE RAINFALL IS
EXPECTED TO OCCUR IN A 12 HOUR PERIOD...BETWEEN 06Z/10 AND 18Z/10.
THIS HEAVY RAINFALL WILL OCCUR ON VERY SATURATED SOILS WHICH WILL
ALLOW RUNOFF TO BEGIN QUICKLY. MANY AREAS OF THE CENTRAL AND WESTERN
PORTIONS OF THE U.P. ARE RUNNING AROUND 2 TO 4 INCHES ABOVE THE 2
WEEK NORMAL DUE TO RECENT HEAVY RAINFALL. SEVERAL RIVERS WITHIN THE
FLOOD WATCH ARE RUNNING HIGHER THAN NORMAL WITH ANY ADDITIONAL
WIDESPREAD RAINFALL EXPECTED TO INCREASE THESE LEVEL...SOME OF WHICH
MAY APPROACH FLOOD STAGE...BASED ON HEAVIER RAINFALL GUIDANCE.
OUTSIDE OF THE RAINFALL POTENTIAL...STRONG WINDS WILL ALSO BE AN
ISSUE. AS THE LOW PUSHES INTO THE REGION...A FAIRLY STRONG AREA OF
HIGH PRESSURE WILL BUILD ACROSS MUCH OF WESTERN CANADA. THE PRESSURE
GRADIENT WILL TIGHTEN BETWEEN THE TWO SYSTEMS LATE TUESDAY NIGHT AND
ESPECIALLY DURING THE DAY WEDNESDAY. THE PERIOD OF STRONGEST WINDS
ARE EXPECTED TO PUSH THROUGH THE AREA LATE WEDNESDAY MORNING THROUGH
LATE WEDNESDAY NIGHT. WINDS OVER MUCH OF THE LAND AREAS AWAY FROM
THE SHORE WILL BE SUSTAINED AROUND 15 TO 25 MPH. OVER THE LAKE...THE
KEWEENAW PENINSULA AND AREAS NEAR THE SHORE WILL SEE WINDS
SUSTAINED CLOSER TO 35 TO 40 MPH WITH GUSTS REACHING AROUND 45 TO
EVEN 50 MPH. THIS IS SUPPORTED WITH CAA ACROSS THE LAKE ON THE BACK
SIDE OF THE LOW WITH RELATIVELY WARM LAKE SURFACE TEMPERATURES
ALLOWING STRONGER WINDS TO MIX DOWN TO THE LAKE SURFACE. SOUNDINGS
SUPPORT WINDS MIXING DOWN FROM AROUND 925-900MB...WHERE WINDS ARE
PROGGED TO BE RIGHT AROUND 45 TO 50 MPH. CONFIDENCE IN HIGH WINDS IS
FAIRLY HIGH OVER THE LAKE...WITH A BIT LOWER CONFIDENCE IN THE WIND
DIRECTION. HAVE DECIDED TO GO WITH A GALE WATCH BEGINNING WEDNESDAY
MORNING INTO LATE WEDNESDAY NIGHT.
THURSDAY THROUGH FRIDAY NIGHT...THE LOW PRESSURE SYSTEM NEAR JAMES
BAY WILL CONTINUE TO SLOWLY LIFT NORTHEAST...PUSHING INTO QUEBEC BY
THURSDAY AFTERNOON. AT THE SAME TIME...STRONG HIGH PRESSURE WILL
BUILD ACROSS MUCH OF THE UPPER MISSISSIPPI VALLEY. THE PRESSURE
GRADIENT MAY LINGER THROUGH THURSDAY MORNING OVER EASTERN LAKE
SUPERIOR KEEPING GALE FORCE GUSTS IN THE FORECAST...HOWEVER...AS THE
LOW SLIPS AWAY AND THE HIGH BUILDS IN...WINDS WILL DIMINISH DURING
THE AFTERNOON HOURS THURSDAY. UPPER LEVEL TROUGHING WILL LINGER
THROUGH FRIDAY NIGHT ACROSS THE AREA WITH A COUPLE SHORTWAVES
PUSHING THROUGH. THE COOLER AIR ALOFT ASSOCIATED WITH THE TROUGH
WILL ALLOW FOR CONTINUED CLOUD COVER ALONG WITH LIGHT RAIN SHOWERS.
BY LATE FRIDAY NIGHT THE HIGH PRESSURE CENTER MOVES OVERHEAD ALONG
WITH SLIGHT RIDGING ALOFT AND DRIER AIR...ALLOWING THE PRECIP TO END
AND SKIES TO CLEAR. TEMPERATURES COULD BE QUITE COOL FRIDAY NIGHT
WITH CALM CONDITIONS...CLEARING SKIES AND PWAT VALUES AROUND 30 TO
40 PERCENT OF NORMAL. KEPT THE IDEA OF SEEING BELOW FREEZING
TEMPERATURES ACROSS INLAND AREAS OF THE U.P.
SATURDAY THROUGH MONDAY...HIGH PRESSURE IS EXPECTED TO LINGER
THROUGH SATURDAY...KEEPING CONDITIONS DRY AND SKIES MAINLY CLEAR.
TEMPERATURES WILL BEGIN TO MODERATE SUNDAY INTO MONDAY ON RETURN
SOUTHERLY FLOW ON THE WEST SIDE OF THE HIGH. THE GFS/EC HAVE ANOTHER
SYSTEM PUSHING INTO THE AREA DURING THE SUNDAY NIGHT INTO MONDAY
TIME PERIOD...HOWEVER...THERE IS QUITE A BIT OF UNCERTAINTY IN THE
TRACK OF THE SYSTEM AND THE OVERALL STRENGTH AND TIMING OF THE UPPER
LEVEL TROUGH. LEANED HEAVILY ON A CONSENSUS OF THE MODELS DURING
THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 130 PM EDT MON SEP 8 2014
EXPECT VFR CONDITIONS THROUGH MOST OF THIS FCST PERIOD WITH STRONG
SSW FLOW TAPPING RELATIVELY DRY AIR SHOWN ON THE 00Z MPX RAOB.
DAYTIME HEATING/MIXING WILL ALLOW FOR GUSTY WINDS TO 20-25 KT THIS
AFTERNOON BEFORE DECOUPLING THIS EVENING MIGHT ALLOW FOR SOME
MARGINAL LLWS BEFORE THE LLJ WEAKENS AFTER 06Z. LOW LEVEL MOISTURE
WILL INCREASE FROM THE SW TUE MORNING WITH MVFR CIGS LIKELY AT IWD
AND CMX AND POSSIBLY AT SAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 402 PM EDT MON SEP 8 2014
SRLY WINDS TO 20 KNOTS WILL CONTINUE TONIGHT BETWEEN HIGH PRES OVER
NEW ENGLAND AND A TROUGH FROM NW ONTARIO INTO THE NRN PLAINS.
LOOK FOR THE TROUGH TO PUSH INTO LAKE SUPERIOR ON TUESDAY...WHILE A
STRONGER LOW ORGANIZES ACROSS THE CENTRAL PLAINS. EXPECT THE
DEEPENING LOW TO SHIFT NE ACROSS WI ON WEDNESDAY...AND ACROSS E
UPPER MI AND N LOWER MI LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING...BEFORE CONTINUING NE INTO QUEBEC ON THURSDAY. A PERIOD OF
N GALES IS EXPECTED FROM WED MORNING THROUGH WED NIGHT. WINDS WILL
DIMINISH THU AS HIGH PRES BUILDS FROM THE PLAINS INTO THE WRN LAKES.
&&
.HYDROLOGY...
ISSUED AT 431 PM EDT MON SEP 8 2014
HEAVY RAINFALL POTENTIAL INCLUDING AREAL FLOOD WATCH...WITH THE DEEP
MOISTURE AND LIFT EXPECTED ACROSS THE AREA...RAINFALL TOTALS WILL
LIKELY EXCEED 2 INCHES WITH UP TO 3 INCHES POSSIBLE ACROSS PORTIONS
OF THE CENTRAL AND WESTERN UPPER PENINSULA. MOST OF THE RAINFALL IS
EXPECTED TO OCCUR IN A 12 HOUR PERIOD...BETWEEN 06Z/10 AND 18Z/10.
THIS HEAVY RAINFALL WILL OCCUR ON VERY SATURATED SOILS WHICH WILL
ALLOW RUNOFF TO BEGIN QUICKLY. MANY AREAS OF THE CENTRAL AND WESTERN
PORTIONS OF THE U.P. ARE RUNNING AROUND 2 TO 4 INCHES ABOVE THE 2
WEEK NORMAL DUE TO RECENT HEAVY RAINFALL. SEVERAL RIVERS WITHIN THE
FLOOD WATCH ARE RUNNING SLIGHTLY HIGHER THAN NORMAL WITH ANY
ADDITIONAL WIDESPREAD RAINFALL EXPECTED TO INCREASE THESE
LEVEL...SOME OF WHICH MAY APPROACH FLOOD STAGE...BASED ON HEAVIER
RAINFALL GUIDANCE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FLOOD WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY EVENING
FOR MIZ001>006-009>013-084.
LAKE SUPERIOR...
GALE WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR
LSZ243>245-264>267.
GALE WATCH FROM WEDNESDAY MORNING THROUGH LATE WEDNESDAY NIGHT
FOR LSZ162-240>242-263.
GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR
LSZ248>251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KEC
AVIATION...JLB
MARINE...JLB
HYDROLOGY...KEC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
404 PM EDT MON SEP 8 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 402 PM EDT MON SEP 8 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS
THE NRN CONUS AND SRN CANADA. A SHORTWAVE TROUGH OVER WI AND
ASSOCIATED 700-300 MB QVECTOR CONV SUPPORTED SOME VERY LIGHT RAIN
SHOWERS OR SPINKLES OVER NRN WI INTO FAR WRN UPPER MI. WITH THE
FORCING MAINLY IN THE 500-300 MB LAYER AND RELATIVELY DRY LOW LEVELS
JUST MID LEVEL CLOUDS/CIGS WERE REPORTED WITH MOST STATIONS NOT EVEN
REPORTING ANY MEASURABLE AMOUNTS. OTHERWISE...PARLTY CLOUDY SKIES
WITH GUSTY SOUTH WINDS OF 15 TO 25 MPH PREVAILED OVER THE REST OF
THE CWA.
TONIGHT...EXPECT THE -SHRA/SPRINKLES OVER SW UPPER MI TO SLOWLY
SLIDE TO THE EAST THIS EVENING AS THE SHRTWV DEPARTS. THE LEFTOVER
MID CLOUDS SHOULD ALSO THIN OUT OVERNIGHT AS QVECTOR DIV SPREADS
INTO THE AREA. HOWEVER...WITH INCREASING SW FLOW 925-700 MB THETA-E
ADVECTION ADDITIONAL CLOUDS MAY SPREAD INTO THE WEST HALF LATE. THE
SRLY FLOW WILL KEEP MIN READINGS IN THE MID 50S INLAND TO AROUND 60
IN DOWNSLOPE LOCATIONS NEAR LAKE SUPERIOR.
TUESDAY...THE MODELS SUGGEST THAT A FRONTAL BOUNDARY WILL SLOWLY
DROP THROUGH WRN LAKE SUPERIOR AND AIDED BY THE LAKE BREEZE INTO THE
NW CWA BY AFTERNOON. THE COMBINATION OF THE APPROACHING FRONTAL
BOUNDARY...MLCAPE VALUES INTO THE 1K-2K RANGE...RELATIVELY WEAK
CAPPING AND THE POTENTIAL A WEAK SHORTWAVE BRUSHING THE AREA MAY
PRODUCE SOME ISOLD/SCT SHRA/TSRA BY MID TO LATE AFTERNOON OVER THE
WEST HALF. SINCE THE STRONGEST FORCING IS EXPECTED TO REMAIN NW OF
THE CWA...ONLY LOWER END CHANCE POPS WERE INCLUDED.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 441 AM EDT MON SEP 8 2014
THE MAIN THREATS THIS PERIOD WILL BE THE HEAVY RAIN TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT...STRONG NORTHERLY WINDS LATE WEDNESDAY
AFTERNOON THROUGH WEDNESDAY NIGHT ALONG LAKE SUPERIOR...AND A
PROLONGED PERIOD OF COOL WEATHER STARTING THURSDAY WITH NEAR OR
BELOW FREEZING TEMPERATURES ANTICIPATED LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING /COOLEST INLAND FROM THE GREAT LAKES/.
TUESDAY...
THE LAST DAY OF ABOVE NORMAL TEMPERATURES...OR EVEN NEAR NORMAL
TEMPERATURES FOR THE NEXT WEEK WILL BE TUESDAY. FAVORABLE S WINDS
OVER THE E HALF OF UPPER MI SHOULD ALLOW AREAS NEAR LAKE SUPERIOR TO
RISE INTO THE MID TO UPPER 70S...WITH LOW 70S COMMON ELSEWHERE. LOOK
FOR A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS OVER THE
W HALF OF THE CWA AS THE SFC TROUGH CONNECTING LOWS OVER CENTRAL
PLAINS AND HUDSON BAY SHIFTS ACROSS THE CWA. BROAD W TO SW FLOW
ALOFT WILL KEEP SWINGING DISTURBANCES ACROSS THE AREA AT 500MB.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...
MODELS ARE COMING INTO BETTER AGREEMENT FOR THE TRACK OF THE SFC LOW
EJECTING NE OUT OF THE CENTRAL PLAINS TUESDAY NIGHT. LOOK FOR THE
SFC LOW TO BE SET UP ACROSS S MN AND IA AT 06Z TO SHIFT OVER S
CENTRAL UPPER MI/NE WI/N LAKE MI BY MID AFTERNOON. THIS WILL BRING
WIDESPREAD RAIN TO THE REGION. WITH PW VALUES RISING TO 1.5-2IN
HEAVY RAIN IS A CONCERN. CURRENTLY HAVE 1.5 TO JUST OVER 2IN OF RAIN
FCST FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. KEPT THE SMALL
CHANCE OF THUNDERSTORMS ALONG LAKE MI WEDNESDAY. WITH THE TRACK OF
THE SFC LOW...AND STRONG HIGH PRESSURE SET UP OVER CENTRAL AND S
ALBERTA/SASKATCHEWAN...STRONG N WINDS OF 40-45MPH WILL BE POSSIBLE
LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...WITH THE
STRONGEST WINDS MOSTLY LIKELY ACROSS THE KEWEENAW PENINSULA. A WIND
ADVISORY MAY BE NEEDED FOR THE KEWEENAW PENINSULA. AS PREVIOUSLY
NOTED...EVEN IF WINDS DON/T QUITE REACH ADVISORY CRITERIA...TREES
COULD BE MORE SUSCEPTIBLE TO FALLING DUE TO THE SATURATED GROUND AND
PLENTY OF LEAVES ON THE TREES.
WEDNESDAY NIGHT THROUGH SUNDAY...
THE SFC LOW WILL SHIFT OVER ONTARIO AND QUEBEC WEDNESDAY
NIGHT...WITH THE SFC TROUGH LINGERING ACROSS UPPER MI INTO THURSDAY.
NW FLOW WILL BRING IN PLENTY OF COLD AIR BEHIND THE LOW...WITH
TEMPERATURES REMAINING WELL BELOW NORMAL THROUGH AT LEAST THE
UPCOMING WEEKEND. 850MB TEMPS OF -1C BY 18Z THURSDAY WILL RESULT IN
LAKE EFFECT RAIN WHICH WILL LINGER THROUGH FRIDAY AS A SECOND WAVE
AND TROUGH AXIS MORE ACROSS THE CWA THURSDAY NIGHT-FRIDAY.
HAVE ADDED THE POTENTIAL FOR NEAR OR BELOW FREEZING TEMPS INLAND
FROM THE GREAT LAKES...AND PRIMARILY OVER THE W HALF OF UPPER MI
LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING AS THE LARGE AREA OF
HIGH PRESSURE TO THE W BUILDS OVERHEAD WITH DECREASING CLOUDS. WINDS
WILL BECOME MORE W OR OUT OF THE S ON SATURDAY...EFFECTIVELY ENDING
OUR LAKE EFFECT CLOUDS OR SHOWERS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 130 PM EDT MON SEP 8 2014
EXPECT VFR CONDITIONS THROUGH MOST OF THIS FCST PERIOD WITH STRONG
SSW FLOW TAPPING RELATIVELY DRY AIR SHOWN ON THE 00Z MPX RAOB.
DAYTIME HEATING/MIXING WILL ALLOW FOR GUSTY WINDS TO 20-25 KT THIS
AFTERNOON BEFORE DECOUPLING THIS EVENING MIGHT ALLOW FOR SOME
MARGINAL LLWS BEFORE THE LLJ WEAKENS AFTER 06Z. LOW LEVEL MOISTURE
WILL INCREASE FROM THE SW TUE MORNING WITH MVFR CIGS LIKELY AT IWD
AND CMX AND POSSIBLY AT SAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 402 PM EDT MON SEP 8 2014
SRLY WINDS TO 20 KNOTS WILL CONTINUE TONIGHT BETWEEN HIGH PRES OVER
NEW ENGLAND AND A TROUGH FROM NW ONTARIO INTO THE NRN PLAINS.
LOOK FOR THE TROUGH TO PUSH INTO LAKE SUPERIOR ON TUESDAY...WHILE A
STRONGER LOW ORGANIZES ACROSS THE CENTRAL PLAINS. EXPECT THE
DEEPENING LOW TO SHIFT NE ACROSS WI ON WEDNESDAY...AND ACROSS E
UPPER MI AND N LOWER MI LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING...BEFORE CONTINUING NE INTO QUEBEC ON THURSDAY. A PERIOD OF
N GALES IS EXPECTED FROM WED MORNING THROUGH WED NIGHT. WINDS WILL
DIMINISH THU AS HIGH PRES BUILDS FROM THE PLAINS INTO THE WRN LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FLOOD WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY EVENING
FOR MIZ001>006-009>013-084.
LAKE SUPERIOR...
GALE WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR
LSZ243>245-264>267.
GALE WATCH FROM WEDNESDAY MORNING THROUGH LATE WEDNESDAY NIGHT
FOR LSZ162-240>242-263.
GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR
LSZ248>251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
131 PM EDT MON SEP 8 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM EDT MON SEP 8 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT ZONAL FLOW
ALF ALONG THE CNDN BORDER. A SHRTWV RDG EMBEDDED IN THIS W-E FLOW IS
MOVING THRU THE UPR LKS EARLY THIS MRNG...SUPPORTING SFC HI PRES
OVER THE SE GREAT LKS. ACYC SW FLOW ARND THIS HI AND DRY AIRMASS
SHOWN ON LOCAL 00Z RAOBS...ESPECIALLY AT MPX WHERE THE 00Z PWAT IS
0.48 INCH OR 60 PCT OF NORMAL...ARE RESULTING IN MOCLR CONDITIONS
ACRS UPR MI. BUT HI CLDS ARE APRCHG WRN UPR MI IN ADVANCE OF A
SHRTWV MOVING E THRU THE NRN PLAINS IN THE SRN BRANCH FLOW. ANOTHER
SHRTWV WITHIN THE STRONGER NRN BRANCH IS PUSHING EWD THRU SRN
SASKATCHEWAN.
MAIN FCST CONCERNS IN THE SHORT TERM WL BE WHETHER AND IF THEN HOW
QUICKLY SHOWERS SPREAD INTO UPR MI IN ADVANCE OF UPSTREAM SHRTWVS.
TODAY...SRN BRANCH DISTURBANCE IN THE NRN PLAINS EARLY THIS MRNG IS
PROGGED TO MOVE E AND INTO NRN WI BY 00Z TUE. ALTHOUGH UPR MI WL BE
ON THE FAVORED CYC SIDE OF THE TRACK OF THIS DISTURBANCE...
PERSISTENT SW FLOW ARND SFC HI PRES MOVING INTO NEW ENGLAND WL
ADVECT DRIER AIR FM THE SW AND THE DIRECTION OF MPX. SO ALTHOUGH
PVA/H5-3 QVECTOR CNVGC AHEAD OF THE SHRTWV IS FCST TO IMPACT MAINLY
THE S HALF OF UPR MI...MODELS INDICATE AN ABSENCE OF ANY SGNFT H85-5
QVECTOR CNVGC. THIS SETUP SUGGESTS THE MAIN IMPACT WL BE THE HI CLDS
SPILLING E FM MN. SO EVEN THOUGH SOME MODELS GENERATE PCPN NEAR THE
WI BORDER AFTER 18Z...OPTED TO MAINTAIN GOING DRY FCST. FCST H85
TEMPS RANGING FM ABOUT 11C OVER THE E TO 13C OVER THE W AND MIXING
TO H8-85 AS OBSVD UPSTREAM YDAY SUPPORTS HI TEMPS IN THE MID/UPR
70S. SSW FLOW OFF LK MI WL BRING COOLER WX TO THE ERN CWA. THE
DAYTIME HEATING/MIXING AND H925 WINDS IN THE 20-30KT RANGE WL RESULT
IN GUSTY WINDS BY LATE MRNG. GIVEN THE FVRBL CONDITIONS FOR GUSTY
WINDS...BUMPED UP FCST GUSTS A COUPLE OF KTS ABV WIND GUST PROCEDURE
OUTPUT.
TNGT...UPR MI IS FCST TO BE DOMINATED BY DEEP LYR QVECTOR DVGC BTWN
DEPARTING SRN BRANCH SHRTWV THRU NRN LOWER MI AND NRN BRANCH
DISTURBANCE CROSSING NW ONTARIO. SO ALTHOUGH THE PERSISTENT SW FLOW
BTWN THE HI PRES MOVING INTO THE CNDN MARITIMES AND AN APRCHG COLD
FNT ATTENDANT TO THE NRN BRANCH SHRTWV WL BRING A RETURN OF HIER H85
THETA E INTO THE UPR LKS...LINGERING MID LVL DRY AIR BEST SHOWN BY
THE 00Z GFS FCST SDNGS WARRANTS KEEPING THE GOING DRY FCST. STEADY
SW WIND AND INCRSG LLVL MSTR THAT MAY RESULT IN SOME SC ESPECIALLY
OVER THE W HALF CLOSER TO THE HIER H85 THETA E WL RESULT IN WELL ABV
NORMAL MIN TEMPS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 441 AM EDT MON SEP 8 2014
THE MAIN THREATS THIS PERIOD WILL BE THE HEAVY RAIN TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT...STRONG NORTHERLY WINDS LATE WEDNESDAY
AFTERNOON THROUGH WEDNESDAY NIGHT ALONG LAKE SUPERIOR...AND A
PROLONGED PERIOD OF COOL WEATHER STARTING THURSDAY WITH NEAR OR
BELOW FREEZING TEMPERATURES ANTICIPATED LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING /COOLEST INLAND FROM THE GREAT LAKES/.
TUESDAY...
THE LAST DAY OF ABOVE NORMAL TEMPERATURES...OR EVEN NEAR NORMAL
TEMPERATURES FOR THE NEXT WEEK WILL BE TUESDAY. FAVORABLE S WINDS
OVER THE E HALF OF UPPER MI SHOULD ALLOW AREAS NEAR LAKE SUPERIOR TO
RISE INTO THE MID TO UPPER 70S...WITH LOW 70S COMMON ELSEWHERE. LOOK
FOR A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS OVER THE
W HALF OF THE CWA AS THE SFC TROUGH CONNECTING LOWS OVER CENTRAL
PLAINS AND HUDSON BAY SHIFTS ACROSS THE CWA. BROAD W TO SW FLOW
ALOFT WILL KEEP SWINGING DISTURBANCES ACROSS THE AREA AT 500MB.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...
MODELS ARE COMING INTO BETTER AGREEMENT FOR THE TRACK OF THE SFC LOW
EJECTING NE OUT OF THE CENTRAL PLAINS TUESDAY NIGHT. LOOK FOR THE
SFC LOW TO BE SET UP ACROSS S MN AND IA AT 06Z TO SHIFT OVER S
CENTRAL UPPER MI/NE WI/N LAKE MI BY MID AFTERNOON. THIS WILL BRING
WIDESPREAD RAIN TO THE REGION. WITH PW VALUES RISING TO 1.5-2IN
HEAVY RAIN IS A CONCERN. CURRENTLY HAVE 1.5 TO JUST OVER 2IN OF RAIN
FCST FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. KEPT THE SMALL
CHANCE OF THUNDERSTORMS ALONG LAKE MI WEDNESDAY. WITH THE TRACK OF
THE SFC LOW...AND STRONG HIGH PRESSURE SET UP OVER CENTRAL AND S
ALBERTA/SASKATCHEWAN...STRONG N WINDS OF 40-45MPH WILL BE POSSIBLE
LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...WITH THE
STRONGEST WINDS MOSTLY LIKELY ACROSS THE KEWEENAW PENINSULA. A WIND
ADVISORY MAY BE NEEDED FOR THE KEWEENAW PENINSULA. AS PREVIOUSLY
NOTED...EVEN IF WINDS DON/T QUITE REACH ADVISORY CRITERIA...TREES
COULD BE MORE SUSCEPTIBLE TO FALLING DUE TO THE SATURATED GROUND AND
PLENTY OF LEAVES ON THE TREES.
WEDNESDAY NIGHT THROUGH SUNDAY...
THE SFC LOW WILL SHIFT OVER ONTARIO AND QUEBEC WEDNESDAY
NIGHT...WITH THE SFC TROUGH LINGERING ACROSS UPPER MI INTO THURSDAY.
NW FLOW WILL BRING IN PLENTY OF COLD AIR BEHIND THE LOW...WITH
TEMPERATURES REMAINING WELL BELOW NORMAL THROUGH AT LEAST THE
UPCOMING WEEKEND. 850MB TEMPS OF -1C BY 18Z THURSDAY WILL RESULT IN
LAKE EFFECT RAIN WHICH WILL LINGER THROUGH FRIDAY AS A SECOND WAVE
AND TROUGH AXIS MORE ACROSS THE CWA THURSDAY NIGHT-FRIDAY.
HAVE ADDED THE POTENTIAL FOR NEAR OR BELOW FREEZING TEMPS INLAND
FROM THE GREAT LAKES...AND PRIMARILY OVER THE W HALF OF UPPER MI
LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING AS THE LARGE AREA OF
HIGH PRESSURE TO THE W BUILDS OVERHEAD WITH DECREASING CLOUDS. WINDS
WILL BECOME MORE W OR OUT OF THE S ON SATURDAY...EFFECTIVELY ENDING
OUR LAKE EFFECT CLOUDS OR SHOWERS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 130 PM EDT MON SEP 8 2014
EXPECT VFR CONDITIONS THROUGH MOST OF THIS FCST PERIOD WITH STRONG
SSW FLOW TAPPING RELATIVELY DRY AIR SHOWN ON THE 00Z MPX RAOB.
DAYTIME HEATING/MIXING WILL ALLOW FOR GUSTY WINDS TO 20-25 KT THIS
AFTERNOON BEFORE DECOUPLING THIS EVENING MIGHT ALLOW FOR SOME
MARGINAL LLWS BEFORE THE LLJ WEAKENS AFTER 06Z. LOW LEVEL MOISTURE
WILL INCREASE FROM THE SW TUE MORNING WITH MVFR CIGS LIKELY AT IWD
AND CMX AND POSSIBLY AT SAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 AM EDT MON SEP 8 2014
FOG MAY CONTINUE TO BE A CONCERN INITIALLY OVER PORTIONS OF W AND
CENTRAL LAKE SUPERIOR. LAKE SUPERIOR WILL INITIALLY BE STUCK BETWEEN
EXITING HIGH PRESSURE OVER THE NEW ENGLAND STATES...AND A NEARING
TROUGH STRETCHING FROM NORTH DAKOTA THROUGH NORTHERN ONTARIO. LOOK
FOR THE TROUGH TO PUSH INTO LAKE SUPERIOR ON TUESDAY...WHILE A
STRONGER LOW ORGANIZES ACROSS THE CENTRAL PLAINS. EXPECT THE
DEEPENING LOW TO SHIFT NE ACROSS WI ON WEDNESDAY...AND ACROSS E
UPPER MI AND N LOWER MI LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING...BEFORE CONTINUING NE INTO QUEBEC ON THURSDAY. A PERIOD OF
N GALES WILL BE POSSIBLE LATE TUESDAY NIGHT INTO EARLY THURSDAY. IN
LARGE HIGH PRESSURE OVER S ALBERTA AND SASKATCHEWAN THURSDAY IS
EXPECTED TO DIVE ACROSS THE N AND CENTRAL PLAINS...WHILE BUILDING A
RIDGE ACROSS LAKE SUPERIOR ON THURSDAY NIGHT AND FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...JLB
MARINE...KF
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
343 PM CDT MON SEP 8 2014
.SHORT TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 333 PM CDT MON SEP 8 2014
MAIN FORECAST CHALLENGE FOR THE SHORT TERM IS SEVERE POTENTIAL
TUESDAY/TUESDAY EVENING...WITH TEMPERATURES BECOMING THE MAIN
ISSUE IN THE LONGER TERM.
SCATTERED SHOWERS/THUNDERSTORMS CONTINUE ACROSS PORTIONS OF OUR
NORTHEASTERN CWA AHEAD OF A VERY SUBTLE SHORTWAVE TROUGH MOVING
THROUGH THE WESTERLIES. THIS ACTIVITY SHOULD CONTINUE TO SHIFT
EAST WITH THE SHORTWAVE ENERGY THROUGH THE EVENING AND OVERNIGHT
HOURS. MOSTLY SUNNY CONDITIONS ACROSS THE REMAINDER OF THE CWA
HAVE ALLOWED A DIURNALLY DRIVEN CU FIELD TO DEVELOP. BOTH THE
LATEST HRRR AND THE RAP INDICATE SOME CONVECTIVE ACTIVITY
DEVELOPING OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA AFTER 00Z
ALONG THE THETA-E AXIS AND HAVE INCLUDED SOME LOW POPS TO ACCOUNT
FOR THIS THIS EVENING.
MAIN WEATHER CONCERN COMES ALONG WITH THE SHORTWAVE TROUGH CURRENTLY
ON THE NORTHERN CALIFORNIA COAST. THIS FEATURE WILL DEAMPLIFY AS IT
SLIDES EAST TOWARD COLORADO OVER THE NEXT 24 HOURS. AHEAD OF
THIS...A LEE CYCLONE WILL DEEPEN AND MOVE INTO SOUTHWESTERN KANSAS
BY 00Z WED. A WARM FRONT WILL EXTEND E/NE ACROSS KANSAS AND SHOULD
DRIFT INTO OUR SOUTHERN CWA BY MID AFTERNOON. ANY STORMS THAT
DEVELOP WITH THE INCREASING SFC CONVERGENCE NEAR THE FRONT SHOULD
QUICKLY GO SEVERE AND ROTATE WITH INCREASINGLY STRONG SHEAR
PROFILES. AREA CONTINUES TO BE OUTLOOKED IN A SLIGHT RISK IN THE
SWODY2. SOME UNCERTAINTY CONTINUES IN REGARDS TO ANY LATE MORNING/EARLY
AFTERNOON CONVECTIVE CHANCES AHEAD OF A WEAK LEAD SHORTWAVE
EJECTING OUT AHEAD OF THE MAIN TROUGH. WILL CONTINUE SOME SMALLER
POPS FOR THIS...BUT MAIN SEVERE POTENTIAL WILL BE LATE
AFTERNOON/EARLY EVENING. THUNDERSTORMS WILL CONTINUE TO BE
WIDESPREAD AHEAD OF THE APPROACHING SFC LOW AS IT SLIDES NORTHEAST
OVER THE CWA BY 06Z/WED. SOUTHWESTERLY 45-55KT LLVL JET THROUGH
THE EVENING HOURS SHOULD SUSTAIN THUNDERSTORMS AFTER DARK WHEN
HEAVY RAIN RATHER THAN SEVERE STORMS WILL BE A THREAT. PW`S
THROUGH THE EVENING DO APPROACH 2.50" DURING THIS TIME. BY
12Z/WED THE SFC LOW WILL BE CENTERED ACROSS NORTHERN IOWA WITH
SOME LINGERING ACTIVITY THROUGH WED MORNING BEHIND THE LOW.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 333 PM CDT MON SEP 8 2014
A DEEPENING UPPER TROUGH OVER WESTERN CANADA WILL DROP SOUTHEAST
INTO THE CENTRAL PLAINS LATER THIS WEEK BRINGING MUCH COLDER AIR
INTO THE REGION. IN FACT...WE MAY BE APPROACHING RECORD COLD
HIGHS...ESPECIALLY THURSDAY WHEN WE HAVE HIGHS FORECAST IN THE MID
TO UPPER 50S. COLD RAIN IS LOOKING MORE LIKELY ON THURSDAY
NIGHT/FRIDAY MORNING AHEAD OF A SHARPENING UPPER TROUGH. IF TIMING
REMAINS SIMILAR TO WHAT MODELS ARE INDICATING...THE RAIN SHOULD BE
OUT OF THE AREA BY FRIDAY AFTERNOON. THE FORECAST FOR THE WEEKEND
LOOKS DRY WITH SOME SLIGHT MODERATION IN TEMPERATURES.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1217 PM CDT MON SEP 8 2014
GENERALLY VFR CONDITIONS ARE EXPECTED ACROSS EASTERN NEBRASKA TAF
SITES THROUGH 18Z TUESDAY. SCATTERED SHOWERS IN NORTHEAST NEBRASKA
COULD AFFECT KOFK FOR A FEW HOURS THIS AFTERNOON. THEN THERE IS A
SMALL CHANCE THUNDERSTORMS COULD DEVELOP BY 00Z THIS EVENING...BUT
MOST OF THAT ACTIVITY IS EXPECTED TO FIRE SOUTHEAST OF KOMA AND
KLNK. AN INCREASE OF MID LEVEL CLOUDS IS EXPECTED LATE TONIGHT AND
TUESDAY AHEAD OF A STORM SYSTEM MOVING INTO THE PLAINS. WIDESPREAD
THUNDERSTORMS ARE FORECAST AFTER THE END OF THIS TAF CYCLE.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...KERN
LONG TERM...KERN
AVIATION...DERGAN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1227 PM CDT MON SEP 8 2014
.UPDATE...
ISSUED AT 1217 PM CDT MON SEP 8 2014
PESKY SHOWERS CONTINUE ACROSS NORTHEAST NEBRASKA TIED TO A WEAK
WAVE IN MID LEVEL FLOW. PLENTY OF SUNSHINE OUTSIDE OF THESE
SHOWERS WAS ALLOWING INSTABILITY TO INCREASE ACROSS THE AREA EARLY
THIS AFTERNOON. WHILE SOME CAPPING WAS STILL IN PLACE...CONTINUED
EROSION COULD LEAD TO CONVECTIVE DEVELOPMENT IN PARTS OF EASTERN
NEBRASKA AND WESTERN IOWA LATE TODAY OR THIS EVENING. OUTFLOW FROM
EARLIER CONVECTION COULD PROVIDE A FOCUS FOR STORMS IN WEST
CENTRAL IOWA LATER TODAY...EXPANDING INTO SOUTHEAST NEBRASKA THIS
EVENING. WILL CONTINUE WITH OUR MENTION OF SLIGHT CHANCE FOR
STORMS TODAY IN THOSE AREAS. ANOTHER POTENTIAL BOUNDARY OF CONCERN
IS A WARM FRONT EXTENDING FROM NORTHEAST NEBRASKA TO NEAR NEBRASKA
CITY...WITH GUSTY SOUTH WINDS ON THE WARM SIDE OF THIS BOUNDARY
AND SOUTHEAST WINDS ON THE COOLER SIDE. WILL CONTINUE TO MONITOR
THESE AREAS FOR INCREASED POTENTIAL FOR STORMS TODAY AND THIS
EVENING.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 255 AM CDT MON SEP 8 2014
HOW FAR SOUTH INTO THE FA WILL MORNING CONVECTION MAKE IT AND
THEN HOW QUICKLY WILL CONVECTION DEVELOP ON TUESDAY MAIN FORECAST
FOCUS IN THE SHORT TERM...ALTHOUGH SEVERE WEATHER AND HEAVY RAIN
REMAIN IN THE PICTURE FOR LATE TUESDAY.
A MERGING THUNDERSTORM CLUSTER WAS WORKING TOWARD NERN NEBR AS OF
8Z BUT ALSO MOVING INTO MLCAPE VALUE AREAS THAT WERE LESS THAN
500 J/KG PER SPC MESO PAGE. THUS WOULD SUSPECT SOME WEAKENING ON
SE EDGE THIS MORNING WHICH WAS HINTED AT BY 05Z HRRR AND RAP WHICH
KEPT MOST OF THE PRECIP IN FAR NE ZONES OR EVEN NE OF THERE...AS
DID 00Z ECMWF. HOWEVER...THAT SAID CONVECTION WAS MAINTAINING ITS
STRENGTH ENOUGH TO DISCOUNT SHORT TERM MODELS TO SOME DEGREE AND
TO INCREASE POPS IN NERN ZONES THIS MORNING AND KEEP MENTION OF
THEM PER PREV FORECAST IN THE AFTN ALONG E OF MO RIVER. DON/T KNOW
IF IT WILL HOLD TOGETHER AND ROLL DOWN MO RIVER TO OMAHA...BUT
CAN/T RULE THAT OUT ATTM. ALSO SOME HINT BY NAM AND 4KM WRF THAT
SOME NEW DEVELOPMENT COULD OCCUR ON SW SIDE THIS MORNING AND THUS
LEFT IN SMALL POPS FARTHER SW THAN RAP/HRRR WOULD SUGGEST. STILL
COUNTING ON DEBRIS BEING MINIMAL ENOUGH THIS AFTN TO ALLOW MAX
TEMPS TO REACH 80 OR BETTER ALL BUT PERHAPS FAR NERN ZONES.
ALTHOUGH SOME SMALL POPS WERE MAINTAINED TONIGHT...STILL APPEARED
THAT MAIN CONVECTIVE AREAS WOULD EITHER BE TO OUR EAST ON NOSE OF
H85 THETAE RIDGE/JET OR TO OUR WEST AS UPPER TROUGH AND MID LEVEL
MOISTURE APPROACH. THIS MOISTURE...WITH H7 DWPTS FORECAST AT 8-10
DEG C PER NAM/GFS...COULD ALLOW CONVECTION TO START OR INCREASE
FAIRLY EARLY TUESDAY AFTN AND LEAD TO LOCALLY HEAVY RAIN BY
EVENING AS PWATS WILL BE HIGH AND TRAINING OF CELLS PROBABLE.
HOWEVER...A LOT COULD/WILL DEPEND ON INITIAL DEVELOPMENT AND
RESULTANT OUTFLOW OR DIFFERENTIAL HEATING AREAS AND WILL REFRAIN
FROM BLANKET HEAVY RAIN MENTION JUST YET. WITH GENERAL MODEL
CONSENSUS THAT SRN ZONES WOULD BE LAST TO GET WIDESPREAD
CONVECTIVE OVERTURNING...MAX TEMPS IN MID/UPPER 80S ARE POSSIBLE
THERE. ALTHOUGH TEMPS SHOULD BE COOLER FARTHER NORTH...REFRAINED
FROM LOWERING JUST YET AS MORE OF THE WIDESPREAD CONVECTION MAY
HOLD OFF TILL AFTN. POTENTIAL FOR SVR WEATHER ALSO CONTINUES
ESPECIALLY WITH NAM FORECAST HODOGRAPHS FAVORABLY CURVED AHEAD OF
PREFRONTAL TROUGH/COLD FRONT FM OMAHA SWD. LIKE WHERE HEAVIER RAIN
EVENTUALLY SETS UP...SEVERE WEATHER...MAINLY ANY TORNADO
POTENTIAL...TOO WILL BE INFLUENCED BY EARLIER DAY CONVECTION BUT
MENTION OF BOTH SVR+HEAVY RAIN WILL CONTINUE IN THE HWO.
STRONGER CONVECTION COULD LINGER WELL INTO TUESDAY EVENING AND
EVEN EARLY OVERNIGHT HOURS AS LOW LEVEL JET DOESN/T SHIFT SE OF
THE AREA TIL AFTER 06Z PER MODELS...ALTHOUGH STRONGEST AND HEAVY
RAIN THREAT BY MID EVENING SHOULD SHIFT MOSTLY TO SRN AND ERN
ZONES.
ALTHOUGH H85 COOLING WILL LAG DUE TO UPPER FLOW...LOWER LEVEL
COOL/DRY ADVECTION WAS FAIRLY DECENT AND WITH PLENTY OF LOW
CLOUDS LIKELY ON WEDNESDAY...ANY HEATING/RECOVERY WILL BE LIMITED.
GENERALLY TRIMMED BACK BOTH LOWS AND HIGHS. ALTHOUGH A GENERAL
TROUGHING CONTINUED ALOFT...FORCING WAS WEAK PER QG FORECAST FM
GFS AND NAM BY AFTN. SO ALTHOUGH SMALL POPS WERE LEFT IN FOR THE
MORNING WITH A DRY AFTN...MUCH OF ANY PRECIP SHOULD BE PRETTY
LIGHT OR POSSIBLY JUST DRIZZLE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 255 AM CDT MON SEP 8 2014
EXTENDED BEGINS QUITE COOL AS H85 TEMPS LOWER INTO LOW SINGLE
DIGITS THU AND EVEN DROP BELOW ZERO THU NIGHT AS REINFORCING UPPER
SHORTWAVE SENDS EVEN COLDER AIR ACROSS THE FA. THIS WAVE COULD
ALSO SPREAD LIGHT SHOWERS ACROSS THE AREA THU MAKING IT EVEN LESS
LIKELY TO MIX TO H85. THIS IN TURN COULD BRING EVEN COLDER MAX
TEMPS TO THE REGION THAN THIS FORECAST WILL CONTAIN...WHICH WERE
ALREADY NEAR OR BELOW COLDEST MAX TEMPS ON RECORD FOR SEPT 11 OF
58 IN LINCOLN...56 IN OMAHA AND 55 AT NORFOLK.
IF SKIES CLEAR QUICKLY ENOUGH THURSDAY LOWS COULD BE A CATEGORY
COOLER THAN THE GENERALLY 40-45 GOING BY FRIDAY MORNING AND WITH
SURFACE STILL IN VICINITY SAT MORNING MORE 30S COULD BE NEEDED IN
FUTURE FORECASTS THAT DAY AS WELL. OTHERWISE 00Z ECMWF INDICATED
TEMPERATURES SHOULD MODERATE NEXT WEEKEND ALONG WITH PRECIP
HOLDING OFF TILL NEXT WAVE SUN NIGHT. GFS WAS A LITTLE COOLER AND
SUGGESTIVE OF LIGHT PRECIP SAT AS UPPER TROUGH TO BEGIN WEEKEND
WAS A TOUCH MORE AMPLIFIED. FORECAST FOR NEXT SATURDAY AND SUNDAY
WAS KEPT DRY FOR NOW.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1217 PM CDT MON SEP 8 2014
GENERALLY VFR CONDITIONS ARE EXPECTED ACROSS EASTERN NEBRASKA TAF
SITES THROUGH 18Z TUESDAY. SCATTERED SHOWERS IN NORTHEAST NEBRASKA
COULD AFFECT KOFK FOR A FEW HOURS THIS AFTERNOON. THEN THERE IS A
SMALL CHANCE THUNDERSTORMS COULD DEVELOP BY 00Z THIS EVENING...BUT
MOST OF THAT ACTIVITY IS EXPECTED TO FIRE SOUTHEAST OF KOMA AND
KLNK. AN INCREASE OF MID LEVEL CLOUDS IS EXPECTED LATE TONIGHT AND
TUESDAY AHEAD OF A STORM SYSTEM MOVING INTO THE PLAINS. WIDESPREAD
THUNDERSTORMS ARE FORECAST AFTER THE END OF THIS TAF CYCLE.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
UPDATE...DERGAN
SHORT TERM...CHERMOK
LONG TERM...CHERMOK
AVIATION...DERGAN
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
325 PM EDT MON SEP 8 2014
.SYNOPSIS...
WET WEATHER WILL CONTINUE OVERNIGHT AS LOW PRESSURE DRAGS MORE
TROPICAL MOISTURE UP ALONG A STALLED FRONT. DRIER AIR WILL FINALLY
ARRIVE ON TUESDAY AS LOW PRESSURE MOVES FURTHER UP THE MID-ATLANTIC
COAST. WARMER TEMPERATURES AND DRY WEATHER ARE EXPECTED WEDNESDAY
AND THURSDAY. A STRONG COLD FRONT WILL ARRIVE LATE WEEK. THE FRONT
WILL MOVE INTO THE REGION BY THE WEEKEND BEFORE DRIFTING SOUTH
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 3 PM MONDAY...WEAK LOW PRESSURE IS VERY SLOWLY MOVING
NORTHEASTWARD ALONG A FRONT STALLED NEAR INTERSTATE 95. THE LOW
APPEARS TO BE LOCATED NEAR DILLON AND SHOULD MOVE TOWARD
FAYETTEVILLE OVER THE NEXT 3 HOURS. WHILE THIS WILL REMOVE THE
STRONGEST LOW-LEVEL CONVERGENCE AND FOCUS FOR SHOWERS...WE STILL
HAVE A DEEP SOUTHERLY FLOW OF MOISTURE TO DEAL WITH. PRECIPITABLE
WATER VALUES REMAIN 2.2 INCHES INLAND TO 2.4 INCHES ALONG THE COAST.
GIVEN COOL SURFACE TEMPERATURES THE BULK OF OUR INSTABILITY IS
ELEVATED...500 J/KG INLAND TO NEAR 1000 J/KG AT THE COAST.
MODERATE TO HEAVY RAIN WILL CONTINUE ACROSS INTERIOR SE NORTH
CAROLINA AND NEARBY PORTIONS OF INTERIOR NE SOUTH CAROLINA FOR THE
NEXT FEW HOURS. THE FOCUS FOR HEAVY RAIN AFTER DARK WILL PROBABLY
SHIFT OFFSHORE SOUTH OF OAK ISLAND...ADVECTING BACK ONSHORE IN THE
DEEP SOUTHERLY FLOW. FOR THIS REASON WE WILL MAINTAIN THE FLOOD
WATCH FROM LUMBERTON AND DILLON EASTWARD TOWARD SOUTHPORT AND
WILMINGTON. SOILS ARE SATURATED OVER MOST OF THE WATCH AREA AND ANY
SUSTAINED HEAVY RAINFALL WILL CREATE A FLOODING RISK. WE HAVE
RECEIVED SEVERAL PUBLIC REPORTS VIA FACEBOOK AND PHONE OF 5+ INCHES
OF RAIN MEASURED ACROSS NORTHEASTERN NEW HANOVER COUNTY SO FAR IN
THIS EVENT.
MODELS HAVE COME INTO BETTER AGREEMENT WITH HOW THE EVENT ENDS
TONIGHT...ALTHOUGH THE LAST SEVERAL HRRR RUNS ARE MUCH FASTER WITH
CLEARING THE BACK EDGE OF THE PRECIP OFF THE COAST THAN ANY OF THE
SYNOPTIC GUIDANCE. (GFS, NAM, ECMWF) BY 8 PM I WOULD EXPECT MOST OF
THE RAIN TO HAVE ENDED WEST OF I-95 EXCEPT NEAR LUMBERTON...AND BY
MIDNIGHT THE BACK EDGE OF PRECIP WILL PROBABLY BE THROUGH MYRTLE
BEACH AND WHITEVILLE. IT MAY TAKE UNTIL SUNRISE FOR RAIN TO END IN
WILMINGTON HOWEVER AS THE EASTWARD PROGRESSION OF THE MID-LEVEL
TROUGH BECOMES QUITE SLOW.
LOWS SHOULD RANGE FROM THE UPPER 60S INLAND TO THE LOWER 70S NEAR
THE COAST.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...LOW PRESSURE WILL BE DEPARTING NORTHEAST TUE
MORNING WITH MID LEVEL DRY AIR MOVING IN FROM THE WEST-NORTHWEST.
THIS SHOULD BRING ABOUT A FAIRLY QUICK END TO ANY LINGER PRECIP TUE
MORNING FOR INLAND SITES. ALONG THE COAST MEASURABLE PRECIP MAY HANG
ON INTO EARLY AFTERNOON WITH LOW LEVEL MOISTURE TRAPPED UNDER MID
LEVEL SUBSIDENCE IN THE WAKE OF THE LOW AND ASSOCIATED WITH THE
SLOWLY EXPANDING SOUTHERN CONUS 5H RIDGE. CLOUD COVER WILL ALSO
LINGER ACROSS THE AREA TUE. GRADUAL CLEARING WILL OCCUR FROM WEST TO
EAST IN THE AFTERNOON BUT THE NC COAST IS LIKELY TO REMAIN CLOUDY
THROUGH SUNSET. TEMPERATURES WILL BE A MIXED BAG WITH INLAND AREAS
RUNNING WARMER DUE TO BREAKS OF SUN LATER IN THE DAY AND SUBTLE
HEIGHT INCREASES. ALONG THE COAST HIGHS WILL BE NEAR TO SLIGHTLY
BELOW CLIMO. CLEARING LATE TUE NIGHT COULD ALLOW FOR A PERIOD OF LOW
STRATUS OR FOG JUST BEFORE DAYBREAK. LATE CLOUD/FOG WILL HELP KEEP
LOWS NEAR CLIMO TUE NIGHT.
MODIFIED HIGH PRESSURE WILL BUILD IN FROM THE WEST ON WED AS MID
LEVEL RIDGE OVER THE SOUTH CONTINUES TO EXPAND EAST. FORECAST
SOUNDINGS SHOW DEEP DRY AIR BUILDING IN...WHICH SHOULD PRODUCE
PARTLY TO MOSTLY SUNNY SKIES. DEEP DRY AIR ALONG WITH WESTERLY FLOW
ALOFT AND LOW LEVEL NORTHEAST FLOW WILL PREVENT DEVELOPMENT OF ANY
MEANINGFUL CONVECTION WED AND PRECIP CHANCES WILL BE NEAR ZERO.
AFOREMENTIONED NORTHEAST FLOW IN THE BOUNDARY LAYER WILL KEEP HIGHS
ALONG THE COAST A LITTLE COOLER...THOUGH STILL ABOVE CLIMO. TEMPS
WED AFTERNOON WILL RANGE FROM LOW 90S INLAND SC TO MID 80S ALONG THE
NC COAST. WEAK WARM ADVECTION DEVELOPS WED NIGHT AS SURFACE RIDGE
AXIS SHIFTS OFFSHORE. SOME MOISTURE RETURN ALONG WITH LIGHT BOUNDARY
LAYER FLOW MAY ALLOW DEVELOPMENT OF FOG LATE IN THE PERIOD. LIGHT
RETURN FLOW AND POTENTIAL FOG WILL KEEP LOWS A LITTLE ABOVE CLIMO.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 3 PM MONDAY...WEAK HIGH PRESSURE WILL REMAIN OVER THE AREA
EARLY THURS AS RIDGE HOLDS ON ALOFT...BUT BY LATE THURS INTO
FRIDAY A COLD FRONT WILL MOVE INTO THE CAROLINAS. SHOULD REMAIN
DRY FOR THURS AT LEAST OVER MOST OF AREA BUT BY THURS NIGHT INTO
FRI...EXPECT INCREASED SHOWER AND THUNDERSTORM ACTIVITY AS FRONT
MOVES THROUGH THE CAROLINAS. PCP WATER VALUES AS LOW AS 1.4 INCHES
THURS MORNING WILL RAMP UP GREATER THAN 2 INCHES JUST AHEAD AND
ALONG COLD FRONT AS IT MOVES SOUTH THROUGH FRI. LOOKS LIKE FRONT
WILL GET HUNG UP OVER THE COAST THROUGH AT LEAST SATURDAY AS
SHORTWAVE LIFTS OFF TO THE NORTHEAST LEAVING A BROAD TROUGH OF LOW
PRESSURE IN THE MID TO UPPER LEVELS. THIS MAINTAINS A SW FLOW
ALOFT RUNNING PARALLEL TO THE FRONT AND MAY KEEP FRONT HUNG UP
OVER OR NEARBY AREA THROUGH MUCH OF THE WEEKEND. A MORE VIGOROUS
SHORTWAVE MAY REACH FAR ENOUGH SOUTH TO GIVE FRONT A PUSH OFF
SHORE BY THE LATTER HALF OF THE WEEKEND. OVERALL EXPECT CLOUDS AND
PCP IN FORECAST FOR MUCH OF FRI AND SATURDAY WITH SOME CLEARING BY
LATE SUNDAY INTO MONDAY AS HIGH PRESSURE BUILDS DOWN FROM THE
NORTH. NOT A HIGH CONFIDENCE FORECAST IN TERMS OF HOW FAR SOUTH
THE FRONT WILL INITIALLY MAKE IT BEFORE STALLING. TOUGH WIND
FORECAST WITH SOUTHERLY WINDS AHEAD OF FRONT THURS INTO FRI BUT
MAY SEE WINDS BECOME VARIABLE OR NORTH AS FRONT REACHES INTO AREA
OVER THE WEEKEND.
EXPECT TEMPS UP AROUND 90 OR SO ON THURS...BUT BY FRI INTO SATURDAY
CLOUDS AND SHWRS WILL AFFECT THE TEMPS AND THEN SOME COOLER AIR WILL
BEGIN TO MOVE IN BEHIND FRONT LATER ON SATURDAY INTO
SUNDAY...KEEPING TEMPS IN THE LOWER 80S OVER THE WEEKEND INTO EARLY
NEXT WEEK. WILL SEE SOME READINGS IN THE 70S FOR HIGHS INLAND WITH
COMBINATION OF COOLER AIR MOVING IN FROM THE N-NW AND CLOUDS AND PCP
OVER THE AREA LATE OVER THE WEEKEND.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...AT KFLO/KLBT IFR/TEMPO LIFR WILL CONTINUE AT LEAST INTO
THE EARLY EVENING HOURS. GRADUAL IMPROVEMENT IN VSBYS EXPECTED THIS
AFTERNOON AS RA ENDS FROM W-E AND WINDS BECOME N. AT THE COASTAL
TERMINALS VFR/TEMPO MVFR EXPECTED WITH PREDOMINATE SHRA. ISOLATED
TSRA POSSIBLE BUT WILL NOT INCLUDE IN TAFS ATTM. DUE TO QUICK
MOVEMENT OF ISOLATED HEAVIER SHRA BRIEF PERIODS OF IFR POSSIBLE AT
COASTAL TERMINALS. AT THE COASTAL TERMINALS WINDS WILL BE S-SW AND
GUSTY...EXCEPT LIGHT SE AT KILM.
PRECIPITATION ENDS COASTAL TERMINALS THIS EVENING. IFR WILL IMPROVE
TO MVFR KFLO/KLBT OVERNIGHT AS WEAK HIGH PRESSURE/SUBSIDENCE BUILDS
IN. SOME IFR POSSIBLE COASTAL TERMINALS OVERNIGHT. SUB-VFR
CONDITIONS IMPROVE TO VFR MID MORNING AT KFLO/KLBT AND COASTAL
TERMINALS LATE IN THE TAF VALID PERIOD AS WINDS BECOME WESTERLY.
EXTENDED OUTLOOK...CHANCE OF SHOWERS EARLY TUESDAY. OTHERWISE VFR
WILL DEVELOP TUESDAY AND PERSIST THROUGH THURSDAY. SHOWERS/TSTMS
RETURN ON FRIDAY AS ANOTHER COLD FRONT APPROACHES THE TERMINALS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM MONDAY...LOW PRESSURE IS MOVING NORTHEAST ALONG A
NEARLY STATIONARY FRONT NEAR INTERSTATE 95 AND SHOULD PUSH INTO
NORTHEASTERN NORTH CAROLINA LATE TONIGHT. THIS WILL DRAG THE FRONT
DOWN TOWARD THE COAST WITH WINDS VEERING MORE WESTERLY LATE ALONG
THE SOUTH CAROLINA COAST. ALTHOUGH RAINFALL INTENSITY HAS REALLY
DIMINISHED THIS AFTERNOON...ADDITIONAL WAVES OF SHOWERS AND
THUNDERSTORMS WILL PROBABLY DEVELOP LATER THIS EVENING AND AFFECT
THE AREA OVERNIGHT...MOST NUMEROUS IN THE CAPE FEAR WATERS TOWARD
AND AFTER MIDNIGHT.
SOUTH WINDS AHEAD OF THE INLAND LOW INCREASED TO AROUND 20 KNOTS
ALONG THE SOUTH CAROLINA COAST EARLIER TODAY WITH 25 KNOT GUSTS.
WIND SPEEDS ALONG THE SOUTH CAROLINA COAST HAVE PEAKED AND SHOULD
DIMINISH GRADUALLY THROUGH THE NIGHT. ALONG THE NC COAST THE
STRONGEST SOUTH WINDS WILL BEGIN TO RAMP UP SHORTLY BUT WILL
PROBABLY ONLY EXCEED 15 KNOTS FOR A FEW HOURS AROUND MIDNIGHT.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...EXITING LOW PRESSURE WILL SLOWLY PUSH THE
STALLED FRONT OFF THE COAST DURING TUE. SOUTHWEST FLOW AT THE START
OF THE PERIOD WILL GRADUALLY VEER TO WEST-NORTHWEST LATER TUE AND
TUE NIGHT. GRADIENT REMAINS WEAK AND THE LACK OF ANY COLD PUSH WILL
KEEP WIND SPEEDS 10 KT OR LESS BOTH PRE AND POST FRONT. ELONGATED
SURFACE HIGH BUILDS IN FROM THE WEST WED WITH WINDS VEERING TO
NORTHERLY DURING THE DAY. LATE IN THE DAY SURFACE RIDGE AXIS MOVES
OVERHEAD WITH NORTHERLY FLOW UNDER 10 KT BECOMING LIGHT AND HIGHLY
VARIABLE. WEAK RETURN FLOW DEVELOPS LATE IN THE PERIOD AS THE
SURFACE HIGH SHIFTS EAST OF THE WATERS. SEAS 3 TO 4 FT WILL CARRY
OVER FROM THE PREVIOUS FORECAST PERIOD BUT WILL QUICKLY DROP TO 2 TO
3 FT TUE DUE TO THE COMBINATION OF LIGHT WINDS AND OFFSHORE FLOW.
FURTHER REDUCTION IN SEAS IS ANTICIPATED ON WED.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 PM MONDAY...SOUTHERLY WINDS WILL INCREASE THROUGH THURS
BETWEEN BERMUDA HIGH AND COLD FRONT MAKING ITS WAY INTO THE
CAROLINAS....BUT OVERALL EXPECT WINDS TO REMAIN BELOW 15 KTS. MUCH
UNCERTAINTY EXISTS AS TO HOW FAR THE FRONT WILL REACH BEFORE
STALLING AND THEREFORE WILL MAINTAIN SOUTHERLY WINDS THROUGH EARLY
SATURDAY. BY LATE SATURDAY INTO SUNDAY WINDS SHOULD COME AROUND TO
THE NE TO N AS FRONT GETS A PUSH SOUTHWARD. WILL SHOW A NORTHERLY
SURGE UP TO 15 KTS BY SUN MORNING BUT THIS IS ALL DEPENDENT ON HOW
FAR SOUTH THE COLD FRONT MAKES IT AND HOW MUCH COLD AIR BLEEDS SOUTH
INTO THE WATERS. SEAS OF 2 TO 3 FT MAY INCREASE UP TO 3 TO 4 FT IN
INCREASED SOUTHERLY FLOW BY SATURDAY AND MAY SEE A BIT MORE OF AN
INCREASE BY SUNDAY IN COOLER NORTHERLY FLOW BEHIND FRONT.
&&
.TIDES/COASTAL FLOODING...
AS OF 3 PM MONDAY...A LARGE POSITIVE TIDAL ANOMALY ON THE LOWER CAPE
FEAR RIVER AROUND +0.75 FEET SHOULD ALLOW THE RIVER TO FLOOD AT HIGH
TIDE THIS EVENING AND AGAIN TUESDAY MORNING. THE REASONS FOR THIS
ARE ASTRONOMICAL (FULL MOON)...METEOROLOGICAL (RECENT HEAVY RAIN AND
STEADY SOUTH WINDS)...AND NON-METEOROLOGICAL (DEEP DREDGING IN THE
RIVER CHANNEL.) THE COASTAL FLOOD ADVISORY FOR THE LOWER CAPE FEAR
RIVER WILL EXTEND ACROSS THE NEXT TWO HIGH TIDES...10 PM THIS
EVENING AND 1030 AM TUESDAY MORNING.
THE TIDAL ANOMALY MEASURED AT THE MYRTLE BEACH AND WRIGHTSVILLE
BEACH GAUGES APPEARS TO BE DECREASING AS WINDS VEER MORE
SOUTH-SOUTHWESTERLY AND WIND STRESS FORCING (EKMAN SPIRAL) PUSHES
LESS WATER UP AGAINST THE SHORELINE. ASSUMING TIDAL ANOMALIES REMAIN
+0.3 FEET OR LESS WE SHOULD REMAIN BELOW COASTAL FLOODING CRITERIA.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR SCZ024.
NC...FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR NCZ087.
FLOOD WATCH THROUGH TUESDAY MORNING FOR NCZ096-099-105>110.
COASTAL FLOOD ADVISORY FROM 8 PM THIS EVENING TO NOON EDT
TUESDAY FOR NCZ107.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...III
LONG TERM...RGZ
AVIATION...MRR
TIDES/COASTAL FLOODING...TRA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1246 PM EDT MON SEP 8 2014
.SYNOPSIS...
WET WEATHER IS EXPECTED TODAY AS LOW PRESSURE DRAGS TROPICAL
MOISTURE UP ALONG A FRONT THAT HAS STALLED OVER THE EASTERN
CAROLINAS. DRIER AIR BUILDING IN TUESDAY WILL ALLOW FOR A WARMING
TREND WEDNESDAY AND THURSDAY. A FAIRLY ROBUST COLD FRONT MAY ARRIVE
FRIDAY NIGHT OR SATURDAY. THE COLD FRONT WILL MOVE OFF THE COAST
SATURDAY NIGHT WITH HIGH PRESSURE BUILDING IN FROM THE NORTH FOR
SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM MONDAY...RECENT MESOANALYSIS SHOWED 1016 MB LOW
PRESSURE JUST SOUTHWEST OF FLORENCE. THE LOW IS FIRMLY ATTACHED TO
THE FRONT AND SHOULD SLOWLY MOVE NORTHEASTWARD ALONG THE BOUNDARY
THROUGH THE AFTERNOON AND EVENING HOURS. PRECIPITATION IS DRYING UP
BEHIND THE LOW AND THE LAST SEVERAL HRRR RUNS SHOW THIS MAY ACTUALLY
BE THE BACK EDGE OF THE EVENT. I HAVE UPDATED POP GRIDS THROUGH
TONIGHT TO LOWER POPS ACROSS MUCH OF INTERIOR SOUTH CAROLINA PLUS
ROBESON COUNTY NC OVERNIGHT. ALONG THE COAST THE MOISTURE CONVEYOR
CONTINUES AND SHOULD RESULT IN MULTIPLE WAVES OF SHOWERS AND
THUNDERSTORMS CONTINUING. PREVIOUS DISCUSSION FROM 1000 AM FOLLOWS...
AFTER COLLABORATION WITH SURROUNDING NWS OFFICES AND THE NESDIS
SATELLITE PRECIPITATION BRANCH WE HAVE ISSUED A FLOOD WATCH FOR ALL
OF SOUTHEASTERN NORTH CAROLINA PLUS MARLBORO...DARLINGTON AND DILLON
COUNTIES IN SOUTH CAROLINA. THIS DELINEATION WAS CHOSEN BASED ON
GAUGE-MEASURED AND RADAR-OBSERVED RAINFALL OVER THE PAST 24 HOURS
PLUS FORECAST RAINFALL AMOUNTS OF 1-2 INCHES WITH ISOLATED 4-5 INCH
AMOUNTS IN THE NEXT 12-24 HOURS.
THE REGIONS AT HIGHEST RISK FOR FLOODING ARE JUST NORTH OF FLORENCE
FOR THE NEXT 4-8 HOURS AS SLOW-MOVING SHOWERS PIVOT AROUND THE
NORTH SIDE OF THE LOW...AND THEN TONIGHT ACROSS COASTAL NEW
HANOVER AND PENDER COUNTIES AS HEAVY RAIN SHOULD PUSH ONSHORE
AHEAD OF THE APPROACHING LOW. THESE ARE ALSO THE TWO REGIONS THAT
ALREADY HAVE PICKED UP 3-4 INCHES OF RAIN AND REALISTICALLY COULD
NOT HANDLE MORE THAN ANOTHER 1.0 TO 1.5 INCHES OF RAIN IN AN HOUR
WITHOUT CAUSING FLOODING.
A STALLED FRONT LOCATED ROUGHLY FROM CLINTON TO FAYETTEVILLE...
LAURINBURG...DARLINGTON AND SUMTER HAS ACTUALLY BACKED UP TO THE
NORTH A LITTLE EARLY THIS MORNING. THIS IS PROBABLY DUE TO
SOUTHERLY WINDS EAST OF SURFACE LOW BETWEEN SUMTER AND ORANGEBURG.
THIS LOW SHOULD SLOWLY ADVANCE ITS WAY NORTHEASTWARD TODAY AND
TONIGHT. BROAD LOW-LEVEL CONVERGENCE NEAR THIS LOW COUPLED WITH
MORE FOCUSED CONVERGENCE ALONG THE FRONT...PLUS FRICTIONAL
CONVERGENCE OF ONSHORE WINDS ALONG THE COAST SHOULD KEEP PLENTY OF
SHOWERS AND THUNDERSTORMS FIRING THROUGHOUT THE DAY. IN THE UPPER
LEVELS A SERIES OF WEAK UPPER DISTURBANCES MOVING ACROSS THE
CENTRAL APPALACHIANS AND VIRGINIA WILL HELP ACCELERATE THE JET
STREAM FLOW ACROSS THE COASTAL MID-ATLANTIC STATES...PLACING THE
EASTERN CAROLINAS WITHIN THE FAVORABLE RIGHT-ENTRANCE REGION OF
THIS JET MAX. THE SUBSEQUENT UPPER DIVERGENCE WILL HELP ENHANCE
OUR OVERALL SYNOPTIC LIFT ACROSS THE AREA.
THE AIRMASS IS ALREADY CONDITIONALLY UNSTABLE WITH ELEVATED CAPE
RANGING FROM 500 J/KG INLAND TO NEARLY 2000 J/KG ON THE COAST.
THERE WON`T BE A LOT OF DAYTIME HEATING TODAY GIVEN THICK CLOUDS
AND PRECIP...BUT ASSUMING WE CAN PUSH SURFACE TEMPS TO 80 THIS
INSTABILITY WILL BECOME SURFACE-BASED. HIGHS SHOULD RANGE FROM THE
UPPER 70S WEST OF I-95...TO 80-83 ELSEWHERE. IF A LITTLE SUN COULD
PEEK THROUGH ACROSS COASTAL SOUTH CAROLINA SOME MID 80S COULD BE
REALIZED BEFORE SHOWERS DEVELOP AND KNOCK TEMPS BACK DOWN.
PRECIPITATION SHOULD GRADUALLY END OVERNIGHT BEHIND THE SURFACE
LOW AS IT CRAWLS NORTHEASTWARD ALONG THE FRONT.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...FRONTAL LOW WILL BE CROSSING THE REGION ON
TUESDAY. THERE IS STILL SOME MINOR TIMING DIFFERENCES BU THE
SLIGHTLY QUICKER WRF SEEMS TO FIT BEST WITH PREVIOUS THINKING. AFTER
WHAT SHOULD STILL BE A RATHER WET START RAIN CHANCES AND MOREOVER
RAINFALL AMOUNTS WILL BE ON THE WANE BY AFTERNOON AS MID LEVEL
DRYING IN ZONAL FLOW INCREASINGLY OFFSETS THE LINGERING LL FRONTAL
MOISTURE. AS THIS DRYING TREND CONTINUES DOWN INTO THE LOWER LEVELS
TUESDAY NIGHT INTO WEDNESDAY TI WILL NOT ONLY LEAD TO A FURTHER
DECREASE IN RAIN CHANCES (TO NEAR ZERO) BUT ALSO TAKE ON THE FORM OF
DECREASING CLOUD COVER. TEMPS TUESDAY WILL HAVE A COASTAL VS INLAND
RANGE AS THE LATTER MAY SEE SOME BREAKS OF SUN THAT ADD A FEW
DEGREES OF WARMTH. ON WEDNESDAY A WEAK SFC GRADIENT PAIRED WITH SOME
SUBTLE HEIGHT RISES ALOFT SHOULD YIELD SEASONABLE TO SLIGHTLY WARM
TEMPERATURES.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...WARM WEATHER EXPECTED THURSDAY AND FRIDAY WITH
A GRADUAL INCREASE IN RAIN CHANCES STARTING THURSDAY NIGHT AS A COLD
FRONT APPROACHES. THE GFS HAS MADE A CONSIDERABLE SHIFT TOWARDS
QUICKER TIMING WITH THIS BOUNDARY THAT COULD IMPLY THAT FRIDAY IS IN
FACT NOT THAT MILD ANYMORE. POSSIBLE...BUT TOO NEW AN IDEA TO LATCH
ONTO AT THIS POINT. INTERESTINGLY THE 00Z ECMWF IS SLOWER THAN NOT
ONLY PREV MODEL BUT PREV THINKING. BEST GUESS IS THAT HIGHEST POPS
SHOULD COME FRIDAY NIGHT. TEMPERATURES WILL ALSO BE HIGHLY MODULATED
BY THE TIMING OF FROPA AS IT MAY BE PACKING SOME CONSIDERABLY COOLER
AIR.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...AT KFLO/KLBT IFR/TEMPO LIFR WILL CONTINUE AT LEAST INTO
THE EARLY EVENING HOURS. GRADUAL IMPROVEMENT IN VSBYS EXPECTED THIS
AFTERNOON AS RA ENDS FROM W-E AND WINDS BECOME N. AT THE COASTAL
TERMINALS VFR/TEMPO MVFR EXPECTED WITH PREDOMINATE SHRA. ISOLATED
TSRA POSSIBLE BUT WILL NOT INCLUDE IN TAFS ATTM. DUE TO QUICK
MOVEMENT OF ISOLATED HEAVIER SHRA BRIEF PERIODS OF IFR POSSIBLE AT
COASTAL TERMINALS. AT THE COASTAL TERMINALS WINDS WILL BE S-SW AND
GUSTY...EXCEPT LIGHT SE AT KILM.
PRECIPITATION ENDS COASTAL TERMINALS THIS EVENING. IFR WILL IMPROVE
TO MVFR KFLO/KLBT OVERNIGHT AS WEAK HIGH PRESSURE/SUBSIDENCE BUILDS
IN. SOME IFR POSSIBLE COASTAL TERMINALS OVERNIGHT. SUB-VFR
CONDITIONS IMPROVE TO VFR MID MORNING AT KFLO/KLBT AND COASTAL
TERMINALS LATE IN THE TAF VALID PERIOD AS WINDS BECOME WESTERLY.
EXTENDED OUTLOOK...CHANCE OF SHOWERS EARLY TUESDAY. OTHERWISE VFR
WILL DEVELOP TUESDAY AND PERSIST THROUGH THURSDAY. SHOWERS/TSTMS
RETURN ON FRIDAY AS ANOTHER COLD FRONT APPROACHES THE TERMINALS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM MONDAY...QUITE A BELT OF STRONG SOUTHERLY WINDS HAS
DEVELOPED ALONG THE SOUTH CAROLINA COAST IN THE PAST FEW HOURS.
MESOANALYSIS SHOWS THIS IS A TIGHTENING OF THE PRESSURE GRADIENT OUT
AHEAD OF THE LOW WHICH IS NOW CENTERED JUST SOUTHWEST OF FLORENCE
SC. SOUTH WINDS 15-20 KNOTS WITH 25 KNOT GUSTS SHOULD CONTINUE
THROUGH THE AFTERNOON...SPREADING NORTHWARD WITH TIME TO INCLUDE THE
BRUNSWICK COUNTY COASTLINE AS FAR EAST AS CAPE FEAR...THEN SPREADING
NORTH AND EAST OF CAPE FEAR THIS EVENING. FORTUNATELY INLAND AIR
TEMPERATURES ARE NO WARMER THAN OFFSHORE SO THERE IS NO SEABREEZE
COMPONENT TO ADD TO WIND SPEEDS. WAVES OF SHOWERS AND THUNDERSTORMS
WILL CONTINUE TO WHIP NORTHWARD ACROSS THE AREA INTO THE EVENING.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...THE START OF THE PERIOD WILL BE THE MOST
ACTIVE AS LOW PRESSURE MOVES UP FRONTAL BOUNDARY JUST INLAND FROM
THE COAST. THIS WILL TIGHTEN THE GRADIENT TO THE POINT WHERE WINDS
SHOULD BE IN THE 15 TO 20 KT RANGE MOST AREAS...ALTHOUGH WIND
SPEEDS MAY ALREADY BE FALLING OVER SOUTHERN ZONES. SOME 5 FT SEAS
MAY BE AFFECTING WATERS ALONG FRYING PAN SHOALS BUT ENOUGH OF A
NEARSHORE/OFFSHORE GRADIENT EXPECTED TO PRECLUDE CAUTIONARY
HEADLINES. THE EXIT OF THE WAVE WILL LEAD TO FAIRLY RAPID DECREASE
IN WINDS AND SEAS LATE TUESDAY INTO TUESDAY NIGHT FROM SOUTH TO
NORTH. AS WIND SPEEDS DECREASE THERE WILL ALSO BE VEERING IN
DIRECTION AND THE EXITING WAVE PUSHES THE FRONT OFFSHORE. A LIGHT
NORTHERLY WIND IS THUS EXPECTED ON WEDNESDAY AT LEAST TO START THE
DAY. A TURN TO A MORE ONSHORE DIRECTION WILL AT FIRST BE LOCALIZED
AS THE SEA BREEZE KICKS IN BUT THEN SHOULD OCCUR GENTLY AREA-WIDE
AS THE SYNOPTIC SCALE FLOW TURNS TO WEAKLY SOUTHERLY.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 AM MONDAY...JUST A GENTLE SW FLOW DEVELOPING ON THURSDAY
AS THE NORMAL WEST ATLANTIC HIGH PRESSURE HAS TROUBLE GETTING
ESTABLISHED INTO THE SOUTHEAST AND MID ATLANTIC BY SOME LINGER
TROUGHINESS. THIS FLOW REGIME WILL STRENGTHEN ON FRIDAY AS A FAIRLY
STRONG COLD FRONT APPROACHES. MODELS HAVE DIVERGED OVERNIGHT WITH
THE TIMING OF THIS FRONT SO THE DEGREE OF STRENGTHENING HAS COME
INTO QUESTION.
&&
.TIDES/COASTAL FLOODING...
AS OF 600 AM MONDAY...THE LOWER CAPE FEAR RIVER IS EXPECTED TO
EXCEED MINOR COASTAL FLOOD THRESHOLDS DURING HIGH TIDE THIS
MORNING AND A COASTAL FLOOD ADVISORY HAS BEEN ISSUED. THE EVENING
HIGH TIDE WILL BE THE HIGHER OF THE TWO HIGH TIDES AND WE EXPECT
WATER LEVELS WILL BE EVEN HIGHER LATE THIS EVENING. HIGH TIDE IN
DOWNTOWN WILMINGTON IS AT 930 AM AND 10 PM.
THE RISK FOR MINOR COASTAL FLOODING ALONG PORTIONS OF THE LOWER
CAPE FEAR RIVER DURING HIGH TIDE WILL CONTINUE FOR MUCH OF THE
WEEK. THE FULL MOON IS TODAY. THE LATE NIGHT TIDE WILL BE HIGHEST.
THE FULL MOON MAY EXACERBATE ANY FLOOD ISSUES ALONG THE COAST
THIS MORNING AND AGAIN THIS EVE. HIGH TIDE AT THE BEACHES IS
AROUND 7 AM AND 730 PM. HOWEVER...WE DO NOT EXPECT MINOR COASTAL
FLOOD THRESHOLDS TO BE REACHED AT THE BEACHES.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...FLOOD WATCH THROUGH THIS EVENING FOR SCZ017-023-024.
NC...FLOOD WATCH THROUGH THIS EVENING FOR NCZ087.
FLOOD WATCH THROUGH TUESDAY MORNING FOR NCZ096-099-105>110.
COASTAL FLOOD ADVISORY UNTIL 11 AM EDT THIS MORNING FOR NCZ107.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1216 PM CDT MON SEP 8 2014
.UPDATE...
ISSUED AT 1216 PM CDT MON SEP 8 2014
UPDATED THE FORECAST TO SCALE BACK THE SOUTHERN EXTENT OF THE
CLOUD COVER FOR EARLY THIS AFTERNOON. THE FRONT`S SOUTHERN
PROGRESSION HAS SLOWED DUE TO AFTERNOON HEATING SOUTH.
HOWEVER...THE LATEST MESOSCALE MODELS PROG THE FRONT TO ACCELERATE
SOUTHWARD DURING THE LATE AFTERNOON/EARLY EVENING HOURS WITH THE
LOSS OF DAYTIME HEATING. THE REMAINING FORECAST ELEMENTS ARE IN
GOOD SHAPE. THE UPDATED PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 911 AM CDT MON SEP 8 2014
A COLD FRONT CONTINUES TO PROGRESS THROUGH NORTHWEST NORTH DAKOTA
FASTER THAN PREVIOUSLY ANTICIPATED. FURTHERMORE...TRAILING STRATUS
IS QUITE A BIT MORE WIDESPREAD UPSTREAM IN CANADA. AS A
RESULT...UPDATED THE SKY GRIDS TO INCREASE CLOUD COVER NORTH BASED
ON THE CURRENT OBS AND 06Z NAM 1000MB-850MB LAYER RH TRENDS.
THE REMAINING WEATHER ELEMENTS ARE IN GOOD SHAPE. THE UPDATED
PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 634 AM CDT MON SEP 8 2014
GIVEN SATELLITE AND SURFACE OBSERVATION TRENDS THROUGH 11
UTC...THE COLD FRONT IS ARRIVING A BIT EARLIER INTO FAR NORTHEAST
MONTANA AND NORTHWEST NORTH DAKOTA THAN PREVIOUSLY FORECAST. THE
10 UTC RAP AND 06 UTC NAM HAVE CAPTURED THIS WELL...AND HAVE
BLENDED THE PREVIOUS FORECAST TO THEIR SOLUTIONS. THE RESULT...IS
HIGHS ONLY IN THE UPPER 50S ACROSS THE FAR NORTHWEST UNDER LOW
LEVEL STRATUS...AND UPPER 80S FOCUSED CLOSER TO THE SOUTH DAKOTA
BORDER.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT MON SEP 8 2014
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE THE ONSET OF
A MAJOR PATTERN CHANGE LATER TODAY INTO TONIGHT.
CURRENTLY...ARCTIC COLD FRONT...MODIFIED/WARMED AS IT HAS MOVED
SOUTH ACROSS CENTRAL CANADA...CONTINUES TO PUSH SLOWLY SOUTHWARD
ACROSS THE CENTRAL CANADIAN PRAIRIE PROVINCES AHEAD OF/IN RESPONSE
TO A STRONG EMBEDDED IMPULSE ROTATING AROUND A DEEP AREA OF UPPER
LEVEL LOW PRESSURE BUILDING ACROSS THE NORTHERN HUDSON BAY REGION.
AHEAD OF THE FRONT...WAA SPREADING EAST ACROSS THE NORTHERN PLAINS
ALONG TO SOUTH OF A SFC TROUGH.
THE MODIFIED ARCTIC COLD FRONT WILL CONTINUE TO PUSH SOUTH
REACHING THE INTERNATIONAL BORDER 12-15Z...AND THROUGH WEST AND
CENTRAL NORTH DAKOTA LATER THIS EVENING. WILL INITIALLY SEE AN
INCREASE IF LOW TO MID LEVEL CLOUDS ACROSS THE NORTH...ALONG WITH
A WIND SHIFT FROM SOUTHERLY TO NORTHERLY. WILL KEEP THE FORECAST
DRY THROUGH THE AFTERNOON WHEN MOISTURE IS MORE LIMITED. THE
TIMING/PLACEMENT OF THE FRONT WILL CREATE A LARGE SPREAD IN
DAYTIME HIGH TEMPERATURES TODAY...WITH MID/UPPER 60S NORTH AND
MID/UPPER 80S SOUTH.
DEEP LAYER MOISTURE WILL FILTER SOUTHWARD AFTER 00Z BEHIND THE
FROPA...ALONG WITH A MODERATE NORTHEASTERLY UPSLOPE LOW LEVEL FLOW
COMPONENT DEVELOPING NORTH TO SOUTH WITH LOW PRESSURE BUILDING
ACROSS SOUTH DAKOTA. WILL MAINTAIN SLIGHT CHANCES FOR SHOWERS AS
COVERAGE APPEARS TO BE LIMITED. STRATUS DEVELOPMENT LOOKING LIKELY
SO KEPT SKY COVER ELEVATED. REMOVED THUNDER WITH LITTLE
INSTABILITY ADVERTISED BY MODELS. DESPITE THE 0C ISOTHERM ENTERING
MY NORTH LATE TONIGHT...CLOUD COVER SHOULD KEEP TEMPERATURES WELL
ABOVE FROST/FREEZING THRESHOLDS FOR TONIGHT/TUESDAY MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 343 AM CDT MON SEP 8 2014
MUCH COOLER WEATHER AND FROST POTENTIAL CONTINUE TO HIGHLIGHT THE
EXTENDED FORECAST.
THE 00 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN GOOD AGREEMENT
ON COOL HIGH PRESSURE BUILDING ACROSS NORTH DAKOTA TUESDAY THROUGH
THURSDAY...WITH THE POTENTIAL COMMENCEMENT OF RETURN FLOW ACROSS
THE NORTHERN PLAINS AND THE BEGINNING OF A WARMING TREND THIS
WEEKEND AS THE HIGH WEAKENS AND DEPARTS IN THE GREAT LAKES. FROST
IS POSSIBLE ACROSS WESTERN NORTH DAKOTA TUESDAY NIGHT...AND AREA
WIDE WEDNESDAY AND THURSDAY NIGHTS WITH LOWS IN THE 30S. DEPENDING
ON CLOUD COVER...SOME LOCATIONS MAY DROP BELOW FREEZING THURSDAY
NIGHT. IN REGARDS TO PRECIPITATION...ANY SIGNIFICANT PRECIPITATION
IS EXPECTED TO REMAIN TO OUR SOUTH AND EAST AS A COLORADO LOW
PROPAGATES INTO THE MISSISSIPPI VALLEY TUESDAY INTO WEDNESDAY.
SCATTERED RAIN SHOWERS ARE EXPECTED ON TUESDAY... WITH PERHAPS A
RELATIVELY DRY WEDNESDAY WITH SOME SUBSIDENCE BEHIND THE TUESDAY
SHORTWAVE. THE DISTURBANCE THAT HAD THE BEST POTENTIAL TO POSSIBLY
YIELD SOME SNOW ACROSS NORTH DAKOTA THURSDAY IS NOW FORECAST TO
MISS ALL BUT PERHAPS THE VERY FAR SOUTHWEST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1216 PM CDT MON SEP 8 2014
A STRONG COLD FRONT WILL CONTINUE TO SLOWLY PUSH SOUTH THIS
AFTERNOON THROUGH EARLY EVENING. IFR STRATUS ASSOCIATED WITH THE
FRONT MAY IMPACT KISN AND KMOT THIS EARLY AFTERNOON. MVFR TO NEAR
IFR STRATUS IS FORECAST TO OVERSPREAD ALL OF WESTERN AND CENTRAL
NORTH DAKOTA THIS EVENING AND CONTINUE THROUGH THE REMAINDER OF
THE TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TM
SHORT TERM...NH
LONG TERM...AYD
AVIATION...TM
AREA FORECAST DISCUSSION
NWS MEDFORD OR
224 PM PDT MON SEP 8 2014
.DISCUSSION...AS FAR AS THE GENERAL FORECAST GOES, THE PERIOD OF QUIET AND
UNEVENTFUL WEATHER WILL CONTINUE THROUGH AT LEAST THE NEXT WEEK.
MODELS ARE IN FAIRLY GOOD AGREEMENT CONCERNING THE OVERALL PATTERN,
WITH THE USUAL AND EXPECTED DIVERSION OF SOLUTIONS LATER IN THE
TERM. HAVE KEPT THE FORECAST TRENDED TOWARDS A GENERAL MODEL BLEND.
THE UPPER LOW CURRENTLY OVEN NORTHERN CALIFORNIA WILL WORK ITS WAY
EAST THROUGH TONIGHT AS A WEAK DRY COLD FRONT PUSHES IN FROM THE
NORTHWEST THIS EVENING. ALTHOUGH INSTABILITY IS WEAK, LAPSE RATES
ARE PRETTY STEEP IN SOME AREAS, AND MOISTURE WILL BE INCREASED IN
THE MID LEVELS. HIGH RESOLUTION NAM AND HRRR RUNS HAVE ALSO PRODUCED
VARYING AMOUNTS OF REFLECTIVITY OVER THE AREA. WITH ALL THIS IN
MIND, HAVE KEPT THE SLIGHT CHANCE OF THUNDER THAT WAS INTRODUCED
DURING THIS MORNING`S UPDATE, BUT CONFIDENCE REMAINS LOW.
AS MENTIONED ABOVE, THE WEAK FRONT WILL MOVE THROUGH THE AREA THIS
AFTERNOON AND EVENING, WITH TEMPERATURES COMING DOWN CLOSER TO
SEASONAL NORMS TUESDAY AND POSSIBLY WEDNESDAY. THE FRONT WILL ALSO
BRING GUSTY, BUT NOT STRONG, WINDS TO AREAS EAST OF THE CASCADES.
ONSHORE FLOW BEHIND THE FRONT WILL KEEP LOW CLOUDS AT THE COAST
LONGER DURING THE DAY WITH A GOOD CHANCE OF SEEING STRATUS SPREADING
INTO THE ROSEBURG AREA TONIGHT AND TUESDAY MORNING. BOTH THE NAM12
AND TO A CERTAIN EXTENT THE GFS BRING SOME MOISTURE SOUTH OF THE
UMPQUA DIVIDE EARLY TUESDAY MORNING. CONFIDENCE IS NOT VERY HIGH
THAT WE WILL SEE CLOUDS IN MEDFORD.
STEERING WINDS ARE EXPECTED TO TURN BACK TO THE NORTHWEST THIS
AFTERNOON AND STAY NW THROUGH TUESDAY. THIS SHOULD PUSH THE SMOKE
BACK INTO SISKIYOU COUNTY BUT COULD PRESENT PROBLEMS FOR YREKA AND
MOUNT SHASTA AREA.
EXPECT WARMING TREND TO RETURN AGAIN ON THURSDAY AND STAY WITH US
THROUGH NEXT WEEKEND...AS A MIDLEVEL RIDGE BUILDS IN OVERHEAD AND
THE THERMAL TROUGH RETURNS AND EXTENDS NORTHWARD WEST OF THE
CASCADES. TEMPERATURES WILL REMAIN NEAR NORMAL VALUES ON THE EAST
SIDE, AND THIS DIFFERENCE IN TEMPERATURE AND PRESSURE WILL LIKELY
RESULT IN SOME STRONGER EAST WINDS WEDNESDAY NIGHT INTO THURSDAY.
THIS WILL LEAD TO ANOTHER ROUND OF INCREASED FIRE CONCERNS INTO THE
WEEKEND. MODEL SOLUTIONS ARE SHOWING A POSSIBLE LARGER TROUGH
ENTERING THE AREA FROM THE NORTHEAST PACIFIC EARLY NEXT WEEK, BUT
CONFIDENCE IS LOW, ESPECIALLY GIVEN THE BLOCKY LOOKING PATTERN
PRODUCED UPSTREAM BY THE HEMISPHERICAL MODELS DURING THE SAME
PERIOD. GIVEN THE UNCERTAINTY, THE FORECAST REMAINS DRY THROUGH THE
TERM. -BPN
&&
.AVIATION...BASED ON THE 08/18Z TAF CYCLE...CURRENT VISIBLE IMAGE
SHOWS THE MARINE STRATUS GRADUALLY PEELING BACK TOWARDS THE COAST.
BASED ON THE SATELLITE TREND, VFR CONDITIONS COULD DEVELOP FOR A
COUPLE OF HOURS AT KOTH AFTER 22Z. UNTIL THEN IFR/LIFR CONDITIONS
WILL PERSIST WITH GUSTY NORTHERLY WINDS INTO EARLY EVENING. IFR/LIFT
CIGS WILL RETURN THIS EVENING AND CONTINUES INTO TUESDAY MORNING.
ELSEWHERE VFR CONDITIONS WILL CONTINUE FOR THE NEXT 18 HOURS, EXCEPT
FOR OCCASIONAL REDUCTION IN VIS DUE TO AREAS OF SMOKE IN WESTERN
SISKIYOU COUNTY. MODELS SUGGEST MARINE STRATUS WILL PUSH INTO THE
UMPQUA BASIN TOWARDS DAY BREAK TUESDAY WITH WIDESPREAD MVFR CIGS AND
PARTIAL MTN OBSCURATIONS. IT`S POSSIBLE SOME OF THE MARINE STRATUS
COULD. SPILL OVER THE UMPQUA DIVIDE, BUT SHOULD NOT EFFECT KMFR.
-PETRUCELLI
&&
.MARINE...UPDATED 220 PM PDT MON 8 SEP 2014...HIGH PRESSURE
WILL CONTINUE TO BUILD OFFSHORE THIS AFTERNOON AND A THERMAL TROUGH
WILL REDEVELOP ALONG THE COAST. THIS WILL RESULT IN THE RETURN OF
NORTH WINDS AND WIND WAVE DOMINATED SEAS THROUGH THE UPCOMING WEEK.
NORTH WINDS ARE LIKELY TO BE STRONGEST TUESDAY THROUGH WEDNESDAY WITH
GALES POSSIBLE SOUTH OF CAPE BLANCO. -WRIGHT
&&
.FIRE WEATHER...LATEST VISIBLE IMAGE SHOWS SOME CUMULUS BUILD UPS
AROUND THE SHASTA TRINITY NORTHEAST THROUGH MEDICINE BOW PEAK AND
SOUTHEAST MODOC COUNTY. SOME ARE DEVELOPING OVER THE CASCADES AND
HIGHER TERRAIN ON THE EAST SIDE. THE MODELS HINT AT VERY WEAK
INSTABILITY LATE THIS AFTERNOON INTO THIS EVENING. THE MODELS SHOW
SOME INSTABILITY IN THE AFOREMENTIONED AREAS, BUT IT`S MARGINAL AT
BEST. MODELS SOUNDINGS SHOW A WEAK CAP, SO IT`S POSSIBLE THAT THERE
MAY NOT BE A LOT OF VERTICAL DEVELOPMENT. IF ANY ISOLATED STORMS
WERE TO DEVELOP, IT WOULD MOST LIKELY BE BETWEEN 4-8 PM PDT. THE
MAIN CONCERN WILL BE GUSTY WEST TO NORTHWEST WINDS ON THE MID SLOPES
AND RIDGES LATE THIS AFTERNOON AND EVENING AS A DRY COLD FRONT MOVES
THROUGH. AN UPPER TROUGH WILL MOVE NORTH OF THE AREA TUESDAY AND THE
MODELS ARE SUGGESTING WEST TO NORTHWEST WINDS TUESDAY AFTERNOON AND
EVENING COULD BE HIGHER. THE GOOD NEWS IS THAT RELATIVE HUMIDITIES
WILL BE HIGHER, SO WERE NOT EXPECTING RED FLAG CONDITIONS TO BE MET.
THEREFORE WE`LL CONTINUE TO HEADLINE IT IN THE FORECAST. A STRONGER
SHORTWAVE WILL SWING THROUGH IDAHO AND WESTERN MONTANA WITH STRONG
HIGH PRESSURE BUILDING SOUTH INTO EASTERN WASHINGTON AND NORTHEAST
OREGON BY THURSDAY MORNING. A THERMAL TROUGH WILL DEVELOP ALONG THE
OREGON COAST AND THE PATTERN DEVELOPING IS FAVORABLE TO MODERATE TO
STRONG OFFSHORE FLOW ALONG THE CASCADES AND POSSIBLY WESTERN
SISKIYOU COUNTY. ALSO THE MODEL SOUNDINGS SHOW A SUBSIDENCE
INVERSION WHICH COULD RESULT IN MODERATE TO POOR RECOVERIES
WEDNESDAY NIGHT. THE COMBINATION OF MODERATE TO POOR RECOVERIES AND
WIND COULD WARRANT RED FLAG CONDITIONS, BUT THERE`S STILL TIME TO
EVALUATE THIS. FOR NOW WE`LL HEADLINE FOR THIS POTENTIAL JUST TO
RAISE AWARENESS TO THE USERS. -PETRUCELLI
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM
PDT WEDNESDAY FOR PZZ356-376.
HAZARDOUS SEAS WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR PZZ356-376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT
WEDNESDAY FOR PZZ350-356-370-376.
SMALL CRAFT ADVISORY FOR WINDS FROM 5 PM TUESDAY TO 11 PM PDT
WEDNESDAY FOR PZZ350-370.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR
PZZ376.
$$
BPN/MAP/TRW
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1231 PM CDT MON SEP 8 2014
.AVIATION 18Z DISCUSSION...
LOW CLOUDINESS TO PERSIST FOR A FEW MORE HOURS BUT WILL BEGIN TO
BREAK UP TOWARD AND BEYOND 00Z. LOW LEVEL MOISTURE WILL STILL
REMAIN...HOWEVER...AND FOG FORMATION CAN BE EXPECTED OVERNIGHT.
SOME SCT TO BKN LOW LEVEL CIGS CAN AGAIN BE EXPECTED AROUND 12Z
TOMORROW...MAINLY ACROSS THE PLATEAU AREA.
&&
.PREV DISCUSSION... /ISSUED 935 AM CDT MON SEP 8 2014/
DISCUSSION...
LOW CLOUDINESS HANGING ON ACROSS MUCH OF THE MID STATE THIS
MORNING. THE CLEARING LINE EXTENDS FROM JUST EAST OF CKV SOUTHWEST
THROUGH LOBELVILLE. THE LATEST 12Z SOUNDING PAIRED WITH THE NAM
THINKING INDICATES THAT THESE CLOUDS ARE GOING TO BE RATHER TOUGH
TO DISLODGE. THEREFORE...FOR THE UPDATE...WILL GO AHEAD AND LOWER
TEMPS A GOOD 3-5 DEGREES OR SO...MAINLY FOR THE EASTERN HALF OF
THE AREA. WILL ADJUST SKY GRIDS ACCORDINGLY.
OTW...WILL KEEP A SLIGHT CHANCE OF SHOWERS AND TSTMS GOING ACROSS
THE PLATEAU. LATEST HRRR DOES SHOW SOME CONVECTIVE DEVELOPMENT
THIS AFTERNOON. WILL REMOVE THE MORNING 12Z-18Z PART OF THE
SLIGHT CHANCE WEATHER GRID.
UPDATE OUT SHORTLY.
PREV DISCUSSION... /ISSUED 653 AM CDT MON SEP 8 2014/
UPDATE...FOR 12Z AVIATION FORECASTS.
AVIATION...BAND OF LOW CLOUDS THAT COVERED THE SOUTHEASTERN TWO-
THIRDS OF MIDDLE TN EARLY THIS MORNING, WILL SLOWLY BREAK FROM THE
WEST. MVFR CIGS ARE EXPECTED TO HOLD AT BNA THROUGH 18Z, WITH CSV
HOLDING ON TO IFR CONDITIONS THROUGH 15Z, THEN MVFR THROUGH AT
LEAST 20Z. MEANWHILE, CKV SHOULD CONTINUE TO ENJOY VFR CONDITIONS.
FOR TONIGHT...EXPECT CKV AND BNA TO EXPERIENCE VFR CONDITIONS,
WHILE CSV WILL PROBABLY STILL BE PESTERED BY PERIODS OF LOW CLOUDS
AND FOG, ESPECIALLY DURING THE LATTER PART OF THE NIGHT.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 251 PM CDT MON SEP 8 2014
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SHORTWAVE
TROUGH MOVING EAST NORTHEAST OVER NORTHWEST WISCONSIN EARLY THIS
AFTERNOON. IN THE DEFORMATION ZONE OF THIS SHORTWAVE...AN AREA OF
LIGHT RAIN IS MOVING NORTHEAST FROM AMERY TO PHILLIPS. DRY AIR HAS
IMPEDED ITS PROGRESS SO FAR TODAY...BUT SHOULD SEE ENOUGH FORCING
FOR LIGHT RAIN TO MAKE ITS WAY ACROSS NORTH-CENTRAL WISCONSIN THIS
AFTERNOON DESPITE HIGH CLOUD BASES. MOSTLY CLEAR CONDITIONS EXIST
BEHIND THIS SHORTWAVE OVER THE DAKOTAS. THEN THERE IS A STRONG COLD
FRONT MOVING SLOWLY SOUTHEAST ACROSS SOUTH-CENTRAL CANADA. TIMING
OF PRECIP CHANCES TONIGHT AND THE POTENTIAL FOR THUNDERSTORMS ON
TUESDAY ARE THE MAIN FORECAST CONCERNS.
TONIGHT...THE SHORTWAVE WILL MOVE ACROSS THE FORECAST AREA DURING
THE EVENING. LIGHT RAIN IN THE DEFORMATION ZONE WILL MOVE NORTHEAST
ACROSS N-C WISCONSIN EARLY THIS EVENING AND INTO THE UPPER PENINSULA
BY MID-EVENING. DESPITE DECENT MID-LEVEL LAPSE RATES...THE
SHORTWAVE WILL OUTRUN THE MOISTURE AXIS BELOW 700MB...AND AM
COUNTING ON THE DRY AIR BELOW THIS LEVEL TO KEEP DRY CONDITIONS IN
PLACE ELSEWHERE. BEHIND THE SHORTWAVE...MID-LEVELS DRY OUT AS
SUBSIDENCE ARRIVES...BUT MODELS ALSO PROJECT AN INCREASE OF LOW
LEVEL MOISTURE FROM THE CENTRAL PLAINS. BASED ON SATELLITE
IMAGERY...THIS LOOKS OVERDONE AND PROGGED SOUNDINGS CONTINUE TO LOOK
DRY ABOVE 850MB OVERNIGHT. WILL BACK OFF ON THE CLOUD COVER AS WELL
AS PRECIP CHANCES. LOWS MAINLY IN THE 50S.
TUESDAY...AS LOW PRESSURE EMERGES INTO THE CENTRAL PLAINS...A
SHALLOW COLD FRONT WILL DROP SOUTHEAST INTO NORTH-CENTRAL WISCONSIN
AND THE WESTERN UPPER PENINSULA DURING THE AFTERNOON. AHEAD OF THE
FRONT...WEAK THETAE ADVECTION WILL BE ONGOING DURING THE
MORNING...BUT PROGGED SOUNDINGS CONTINUE TO LOOK DRY ABOVE 850MB.
WILL MOST LIKELY NEED TO WAIT FOR DAYTIME DESTABILIZATION TO TAKE
PLACE FOR THE CHANCE OF SHOWERS AND THUNDERSTORMS TO
OCCUR...STARTING EARLY AFTERNOON. BY MID-AFTERNOON...LOW LEVEL
MOISTURE AXIS AND FORCING ALONG THE FRONT SHOULD IMPROVE
THUNDERSTORM CHANCES. ML CAPES AHEAD OF THE BOUNDARY REACH UP TO
1200 J/KG WITH 0-6KM BULK SHEARS OF 20-25 KTS. CANNOT FIND MUCH OF
A CAP BY 21Z...SO THINKING ISOLATED TO LOW END SCT SHOWERS AND
STORMS WILL BE POSSIBLE. COULD SEE AN ISOLATED PULSE SEVERE THREAT
DEVELOP IF INSTABILITY REACHES ITS POTENTIAL. HIGHS IN THE MIDDLE
TO UPPER 70S.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 251 PM CDT MON SEP 8 2014
PRIMARY FOCUS DURING THIS PERIOD IS THE STRONG STORM SYSTEM TO
IMPACT THE REGION THROUGH MID WEEK. STRONG CONVERGENCE WITH A
DEEPENING SURFACE LOW AND H850 LOW TRACKING OVER THE STATE LATE
TUESDAY INTO WEDNESDAY COMBINED WITH PWATS CLIMBING TO A VERY
MOIST 1.50 TO 2.00 INCHES WILL LIKELY PRODUCE A SWATH OF HEAVY
RAIN STARTING TUESDAY EVENING AND CONTINUE INTO WEDNESDAY
AFTERNOON BEFORE GRADUALLY DIMINISHING FROM SOUTHWEST TO NORTHEAST.
JUST ABOUT ALL MAIN STEM RIVERS ARE RUNNING HIGH AND ANTICIPATED
AMOUNTS WOULD LIKELY RAISE LEVELS TO FLOOD STAGE. THE POTENTIAL OF
A WIDESPREAD 1.50 TO AS HIGH AS 3.00 INCHES CONTINUES TO INCREASE.
LOCALLY HIGHER RAINFALL AMOUNTS DUE TO STORMS COULD INCREASE THE
IMPACTS OF THE FLOODING ALONG THE RIVERS AS WELL AS FOR URBAN
AREAS. EVEN THOUGH THERE IS A FLASH FLOOD POTENTIAL...WILL GO WITH
THE FLOOD WATCH VARIETY FOR NOW DUE TO THE HIGHER POTENTIAL OF THE
RIVER FLOODING.
MUCH COOLER TEMPERATURES WITH A SHOT OF BLUSTERY FALL WINDS WILL
POUR INTO THE AREA FOR THE REST OF THE WEEK. MINOR PRECIP CHANCES
WILL CONTINUE FOR THE REMAINDER OF THE WEEK AS A TROUGH OF LOW
PRESSURE SETTLES OVER THE AREA.
COOLER DRIER AIR REMAINS OVER THE WEEKEND WITH THE LIKELY CHANCE
OF THE FIRST FROST OR FREEZE HEADLINE OF THE SEASON FOR THE
NORTHERN PORTION OF THE FORECAST AREA.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1208 PM CDT MON SEP 8 2014
A WEAK DISTURBANCE WILL MOVE ACROSS THE REGION THIS
AFTERNOON AND EVENING AND GENERATE LIGHT SHOWERS AND
SPRINKLES...MAINLY OVER NORTHWEST WISCONSIN. PLENTY OF DRY AIR
CURRENTLY RESIDES ACROSS THE REGION...BUT A FEW SHOWERS COULD
SURVIVE THE TRIP INTO NORTH-CENTRAL WISCONSIN THIS AFTERNOON. CONFIDENCE IS
TOO LOW TO INCLUDE IN THE RHI TAF...AND FLIGHT CATEGORIES SHOULD
REMAIN IN THE VFR RANGE REGARDLESS. ONCE THIS DISTURBANCE EXITS
LATE IN THE EVENING...MODELS DEPICT LOW LEVEL MOISTURE SURGING
NORTHEAST THAT COULD CREATE BKN MVFR CLOUDS LATE TONIGHT OVER
NORTH-CENTRAL WISCONSIN. THE MODELS APPEAR TO BE OVERDOING THE
MOISTURE...HOWEVER...AND CONFIDENCE IS LOW AGAIN THAT WE WILL SEE
MVFR CIGS DEVELOP. LEFT A SCT MENTION TO INDICATE THAT THERE MAY BE
LOW CIGS AROUND LATE TONIGHT. IF CLOUDS DO NOT FORM...VFR
CONDITIONS WILL PREVAIL FOR THE DURATION OF THE FORECAST.
&&
.MARINE...
ISSUED AT 251 PM CDT MON SEP 8 2014
GUSTY SOUTHEAST/SOUTH WINDS MAY DEVELOP WEDNESDAY ACROSS PORTIONS
OF THE MARINE AREA DEPENDING ON TRACK OF THE LOW PRESSURE SYSTEM.
ONCE THE SYSTEM MOVES EAST OF THE AREA... GALE FORCE GUSTS ARE
POSSIBLE WEDNESDAY NIGHT INTO THURSDAY. WINDS AND WAVES WILL
GRADUALLY SUBSIDE THURSDAY AFTERNOON AND EVENING.
&&
.HYDROLOGY...
ISSUED AT 251 PM CDT MON SEP 8 2014
WILL ISSUE A FLOOD WATCH FOR TUESDAY NIGHT INTO WEDNESDAY IN
ANTICIPATION FOR A WIDESPREAD 1.50 TO NEARLY 3 INCH AMOUNTS IN A
24 HOUR PERIOD. THE WATCH WILL ALSO INCLUDE THE AREA WHICH
RECEIVED HEAVY RAIN LAST WEEK AND WHERE RIVER LEVELS AND STREAMS
REMAIN QUITE HIGH. SHOULD NOTE THAT EVEN THOUGH THE HEAVY RAIN
WILL NOT REACH THE AREA UNTIL LATER TUESDAY EVENING...MINOR
FLOODING MAY ACTUALLY START TUESDAY DUE TO HYDRO OPERATIONS
RELEASING WATER EARLY IN ADVANCE OF THE HEAVY RAIN. EVEN THOUGH
THE HEAVY RAINFALL WILL BE ENDING WEDNESDAY AFTERNOON...RUNOFF
EFFECTS INTO AREA RIVES WILL BE ON THE INCREASE WEDNESDAY EVENING
INTO THURSDAY AND IF THE SCENARIO PANS OUT...WARNINGS WILL
PROBABLY BE GOING INTO AFFECT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY EVENING FOR
WIZ005-010>013-018>022-030-031-035>040-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......TDH
AVIATION.......MPC
MARINE.........TDH
HYDROLOGY......TDH