Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/07/14
AREA FORECAST DISCUSSION
NWS ALBANY NY
342 PM EDT FRI SEP 5 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 SATURDAY MORNING/...
AS OF 342 PM EDT...A VERY WARM AND HUMID AFTERNOON WILL GIVE WAY
TO A MUGGY NIGHT...AS OUR REGION REMAINS FIRMLY ENTRENCHED IN A
WARM SECTOR AHEAD OF A COLD FRONT APPROACHING FROM THE GREAT
LAKES. A FEW SHOWERS HAVE POPPED UP NEAR KPOU...SO WILL MENTION
ISOLATED POPS FOR A FEW HOURS EARLY THIS EVENING. OTHERWISE DRY
CONDITIONS WILL PERSIST.
MESOSCALE MODELS SUCH AS THE HRRR AND LOCAL HI RES WRF INDICATING
LINES/CLUSTERS OF CONVECTION WILL DEVELOP AHEAD OF AND ALONG THE
COLD FRONT OVER THE NIAGARA FRONTIER THIS EVENING. AS THIS ACTIVITY
APPROACHES CENTRAL NY LATER THIS EVENING IT IS FORECAST TO WEAKEN 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 SATURDAY 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 /20Z FRIDAY THROUGH WEDNESDAY/...
THE REGION IS IN THE WARM SECTOR OF AN APPROACHING LOW PRESSURE
SYSTEM. CUMULUS CLOUDS WILL DISSIPATE WITH THE LOSS OF HEATING.
TONIGHT INITIALLY CIRRUS THEN MID LEVEL CLOUDS WILL STREAM IN.
MVFR-IFR CONDITIONS ARE EXPECTED TO DEVELOP OVERNIGHT DUE TO FOG
AND STRATUS ESPECIALLY LATE. THE STRATUS WILL LIFT AS WE HEAD INTO
THE MID MORNING PERIOD....HOWEVER LOW LEVEL CLOUDS AHEAD OF THE
LOW PRESSURE SYSTEM COLD FRONT WILL BE OVERSPREADING THE REGION.
CHANCES FOR CONVECTION WILL BE IN THE INCREASE AS WE HEAD INTO
LATE MORNING/EARLY AFTERNOON. AT THIS TIME...HAVE INTRODUCE PROB30
FOR SHOWERS AT KGFL...KALB AND KPSF. THE THREAT EXPECTED TO HOLD
OFF UNTIL AFTER 18Z/SATURDAY AT KPOU. THERE WILL BE CHANCES FOR
STRONG TO SEVERE STORMS DURING THE AFTERNOON MAINLY AT KPSF AND
KPOU WHERE THE ATMOSPHERE WILL BE MORE UNSTABLE. MAIN THREAT OF
FOR STRONG TO DAMAGING WINDS GUSTS.
SOUTHERLY WINDS OF UP TO AROUND 10 KNOTS WITH SOME GUSTS POSSIBLE AT
KALB THIS AFTERNOON...WILL WEAKEN TONIGHT BUT REMAIN OUT OF THE
SOUTH. THE FLOW WILL SHIFT MORE TO THE SOUTH-SOUTHWEST SATURDAY AS
THE COLD FRONT INCREASING TO AROUND 10 KNOTS.
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...JPV
SHORT TERM...JPV
LONG TERM...IAA/LFM
AVIATION...IAA
FIRE WEATHER...JPV
HYDROLOGY...11/JPV
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
855 PM EDT SAT SEP 6 2014
...LOCALLY HEAVY RAINFALL THREAT CONTINUES THROUGH THE WEEKEND...
.UPDATE...
LATEST RUC ANALYSIS HAS SHOWN A SLIGHT SHIFT IN THE STACKED LOW
PRESSURE SYSTEM IN THE ATMOSPHERE TOWARDS THE SE GA COASTLINE JUST
TO THE NORTHEAST OF JACKSONVILLE. SO FAR THIS EVENING STILL LACKING
MUCH SIGNIFICANT CONVECTION/ORGANIZED RAINFALL OVER THE LAND AREAS,
MEANWHILE THE COASTAL WATERS HAVE LIT UP WITH NUMEROUS SHOWERS AND
EMBEDDED STORMS. MODELS IN GENERAL AGREEMENT THAT THE COASTAL WATERS
AND THE COASTAL COUNTIES FROM JACKSONVILLE NORTHWARD TO BRUNSWICK
ARE UNDER THE MOST THREAT FOR ORGANIZED HEAVY RAINFALL. SO FAR
DURING THIS EVENT THESE AREAS HAVE BEEN SPARED THE HEAVY RAINFALL SO
WILL HOLD OFF ON ANY FLASH FLOOD WATCH BUT AS SOON AS EVENT APPEARS
MORE LIKELY DURING THE OVERNIGHT HOURS A SHORT-FUSE WATCH MAY BE
NEEDED. OTHERWISE...MAINLY LINGERING ISOLD TO SCTD SHOWERS WITH
EMBEDDED STORMS POSSIBLE OVER THE REMAINING LAND AREAS AS THE JAX
SOUNDING STILL REPORTED A PRECIPITABLE WATER AMOUNT NEAR 2.25 INCHES
AND SHOWERS COULD POP-UP AT ANY TIME DUE TO THE CLOSE PROXIMITY OF
THE MID LEVEL LOW AND SPOKES OF ENERGY STILL ROTATING AROUND IT.
SKIES WILL GENERALLY REMAIN MOSTLY CLOUDY WITH LOWS IN THE 70S.
&&
.AVIATION...
MVFR CEILINGS WILL INITIALLY BE MOST PREVALENT AT SSI THIS EVENING.
ELSEWHERE...VFR CONDITIONS WILL CONTINUE THROUGH THIS EVENING WITH
MVFR CEILINGS LIKELY DEVELOPING IN THE JACKSONVILLE AREA LATER
TONIGHT DURING THE EARLY MORNING HOURS. RAIN WILL REMAIN HIGHER THAN
NORMAL OVERNIGHT DUE TO UPPER DISTURBANCE LINGERING OVER THE AREA.
TIMING THIS ACTIVITY CONTINUES TO BE DIFFICULT BUT THERE AT LEAST
SEEMS TO BE SOME GENERAL MODEL CONSENSUS POINTING TO RAIN IN THE
JACKSONVILLE AREA LATE TONIGHT INTO TOMORROW MORNING. IFR CONDITIONS
WILL BE POSSIBLE IN HEAVY RAIN WITH SOME OF THIS ACTIVITY LATE
TONIGHT. WILL KEEP VFR CONDITIONS AT GNV WHERE LOWER RAIN CHANCES
ARE EXPECTED.
&&
.MARINE...
S TO SW FLOW OVER THE COASTAL WATERS HAS INCREASED TO 15 TO 20 KNOTS
AND HAVE RAISED SCEC HEADLINE IN THE COASTAL WATERS ALTHOUGH SEAS
WILL STILL GENERALLY REMAIN IN THE 2-4 FT RANGE. STILL MAIN IMPACTS
CONTINUE TO BE NUMEROUS SHOWERS AND EMBEDDED STORMS WITH VERY HEAVY
RAINFALL AND LIGHTNING.
RIP CURRENTS: LOW RISK CONTINUES IN S/SW FLOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 72 91 73 89 / 40 70 60 60
SSI 75 86 74 86 / 50 60 60 60
JAX 72 89 73 90 / 50 70 60 70
SGJ 74 87 74 88 / 50 60 60 60
GNV 70 87 71 89 / 40 60 50 60
OCF 71 88 72 88 / 40 60 50 60
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
HESS/SHULER/WALKER
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
950 AM EDT FRI SEP 5 2014
.UPDATE...
CURRENT...WEAK SURFACE TROUGH OVHD YESTERDAY HAS LIFTED N-NE AND NOW
EXTENDS FROM N FL NEWD INTO COASTAL GA/SC/NC. WEAK LOW CENTER NEAR
THE GA COAST IS PRODUCING WIDESPREAD CONVECTION WELL OFFSHORE FROM
ABOUT KDAB N-NEWD. NE H25 WINDS ARE BLOWING MUCH OF ITS CONVECTIVE
DEBRIS CLOUDS SWWD INTO ECFL. BEHIND (SOUTH OF) THIS FEATURE...THE
ATLC RIDGE IS BUILDING WWD INTO SOUTH CTRL WITH ITS AXIS NR THE LAKE
OKEE REGION. LOOKING ALOFT...THERE IS STILL SOME DECENT REFLECTION
OF THE MID LVL TROUGH OVHD AS SEEN IN WATER VAPOR AND THE RUC H50
VORT/STRMLN ANLYS. WEAK LIFT ASCD WITH THE VORT LOBE IS HELPING TO
MAINTAIN THE MID LEVEL AS/AC DECK NEAR/NORTH OF A KSRQ-KMCO-KDAB
LINE.
MORNING RAOBS SHOW PWATS IN THE 2.0" TO 2.1" OVER THE ENTIRETY OF
THE PENINSULA...WITH H50 TEMPS OF -6C TO -8C LEADING TO SOMEWHAT
ANEMIC LAPSE RATES. THIS IN TURN POINTS TO HEAVY RAIN/LIGHTNING AS
THE PRIMARY STORM THREATS TODAY. LIGHT STEERING WINDS ACROSS THE NRN
HALF CWA BECOMING INCREASINGLY OUT OF THE SW AT AROUND 10KT OVER THE
SRN HALF AS WHAT`S LEFT OF THE MID LEVEL VORT AXIS CONTINUES TO LIFT
NORTH.
POP DISTRIBUTION IN THE GRIDS/ZFP LOOKS PRETTY GOOD. WHILE STRONGER
STEERING FLOW TOWARD THE NE IS IN PLACE OVER THE FAR SERN CWA...THIS
WILL COUNTERACTED BY A MORE RAPID INLAND PUSH TO THE ECSB...SO LOWER
(40 ALONG THE IMMEDIATE ST LUCIE/MARTIN COAST) LOOKS OK THERE.
&&
.AVIATION...EXPECT INCREASING COVERAGE OF SHOWERS/STORMS AREAWIDE
DURING THE LATE MORNING AND AFTERNOON. ONCE AGAIN THE VRB-FPR-SUA
CORRIDOR LOOKS TO HAVE EARLIEST ONSET TIMES WITH INITIAL ECSB
FORMATION THERE (~16Z) SPREADING FARTHER NORTH/INLAND THEREAFTER.
&&
.MARINE...
S-SSW WINDS ACROSS THE MAOR WILL TEND TO BACK MORE TWD THE SSE-SE
THIS AFTERNOON AS ATLC RIDGING BUILDS IN BEHIND THE SFC LOW/TROUGH
TO THE NORTH..WITH A LITTLE MORE SYNOPTIC ONSHORE COMPONENT FARTHER
SOUTH. SPEEDS GENERALLY AOB 10KT WILL KEEP SEAS 2FT (OR A LITTLE
LESS) NEAR SHORE AND 2-3FT WELL OFFSHORE.
&&
UPDATE/AVIATION...CRISTALDI
RADAR/IMPACT WX....WIMMER
&&
.PREV DISCUSSION... /ISSUED 335 AM EDT FRI SEP 5 2014/
SAT...A MID LYR LOW ACROSS SE GA WILL MOVE LITTLE ON SATURDAY WITH
LOW LVL SOUTHERLY FLOW AND DEEP MOISTURE ACROSS E CENTRAL FL. THE
SOUTHERLY FLOW AND DEEP MOISTURE WILL ALLOW FOR DEVELOPMENT OF
MORNING SHOWERS AND AFTERNOON SHOWERS/THUNDERSTORMS WITH A
SLOW-MOVING EAST COAST SEA BREEZE MOVING MOVING TOWARD THE INTERIOR
IN THE AFTERNOON. WILL KEEP POPS MAINLY IN THE 50 PCT RANGE ALONG
THE COAST SOUTH OF THE CAPE AND UP TO 60 PCT ACROSS THE INTERIOR AND
NRN SECTIONS WHERE AFTERNOON STORMS MAY PUSH BACK TWD THE VOLUSIA
COAST IN THE AFTERNOON. WILL DROP TEMPS A FEW DEGREES FROM GFS MOS
HIGH TEMP FCSTS WHICH AGAIN SEEM TOO HIGH GIVEN EXPECTED
CONSIDERABLE CLOUD COVER AND HIGHER THAN NORMAL COVERAGE OF
SHOWERS/STORMS. HIGHS IN THE UPPER 80S COAST TO 90/LWR 90S OVER THE
INTERIOR.
SUNDAY...A FRONTAL BOUNDARY WILL STALL ACROSS GA WITH SFC LOW
PRESSURE OVER SC ON SUNDAY. DEEP MOISTURE WILL CONTINUE OVER THE
AREA WITH A BROAD RIDGE ACROSS THE ATLC ALLOWING FOR LOW LVL SSE
FLOW ACROSS FAR SRN SECTIONS AND SSW/SW FLOW ACROSS NRN LAKE AND
VOLUSIA COUNTIES. RAIN CHANCES WILL BE HIGHEST WEST OF NEW SMYRNA
BEACH TO KENANSVILLE LINE WHERE LIKELY AFTERNOON STORMS ARE
EXPECTED. FARTHER SOUTH ALONG THE TREASURE COAST THE EAST EAST COAST
SEA BREEZE WILL PUSH SLOWLY INLAND WITH 50 PCT RAIN CHANCES ACROSS
SRN BREVARD TO 40 PCT ACROSS COASTAL MARTIN. HIGHS UPPER 80S TO
AROUND 90 COAST TO LOWER 90S INTERIOR.
MONDAY...LOOKS TO BE A TRANSITION DAY TOWARD LOWER RAIN CHANCES INTO
MID WEEK. THE ATLC SFC RIDGE WILL KEEP LOW LVL FLOW FROM THE SE/S
AND HIGHEST RAIN CHANCES WILL OCCUR ACROSS THE INTERIOR WITH 40-50
PCT...AND LOWER ALONG THE COAST FROM 30-40 PCT. SHOULD BE MORE SUN
IN THE MORNING ALLOW HIGH TEMPS TO REACH AROUND 93 FOR THE INTERIOR
TO AROUND 90 ALONG THE EAST COAST.
TUE-FRI...THE ATLC RIDGE WILL BUILD WESTWARD INTO MID TO LATE WEEK
ACROSS E CENTRAL FL WITH LOW LVL SE/ESE FLOW DEVELOPING. 00Z GFS
MODEL INDICATES SOME PRONOUNCED DRYING MAKING ITS WAY ACROSS SRN
SECTIONS BY WED...WITH 00Z ECMWF SHOWING SOME DRIER AIR MAKING IT
HERE ABOUT 24 HOURS LATER BY THU. WILL SHOW A DECREASE IN RAIN
CHANCES BY MID TO LATE WEEK GENERALLY 30 PCT FOR THE COASTAL
COUNTIES AND 30-40 PCT OVER THE INTERIOR. THE DEVELOPING ONSHORE
FLOW SHOULD KEEP COASTAL HIGHS IN THE UPPER 80S TO NEAR 90 TO LOWER
90S ACROSS THE INTERIOR.
&&
.AVIATION...
NMRS SHRA/SCT TSRA OVER LCL ATLANTIC THIS MORNING WITH A FEW
BRUSHING COAST FROM KMLB NORTHWARDS...ESPECIALLY VCNTY KDAB.
ADDITIONAL ISOLD SHRA ALONG WEAK BOUNDARY NORTH OF ORLANDO METRO.
SCT SHRA/TSRA DEVELOPING ALONG COAST WITH EAST COAST SEA BREEZE
AFTER 15Z...AND WITH MORE QUICKLY INLAND MOVING WEST COAST SEA
BREEZE WEST OF ORLANDO METRO. COVERAGE BECOMING NMRS OVER INTERIOR
AND ALONG/NORTH OF I-4 CORRIDOR AFTER 19Z WITH BOUNDARY COLLISIONS
ESPECIALLY EAST/WEST SEA BREEZE LATE AFTN/EARLY EVE. A FEW STORMS
WILL PUSH BACK TO COAST NORTH OF KMLB THROUGH 06/03Z WITH ISOLD SHRA
VCNTY VOLUSIA COAST OVERNIGHT.
&&
.MARINE...
TODAY-TONIGHT...S-SW FLOW AROUND 10KTS THIS MORNING AS LCL ATLC GETS
PLACED ON THE BACKSIDE OF WEAK EASTERLY WAVE/TROUGH LIFTING NORTH
AROUND WEST SIDE OF ATLANTIC RIDGE. FLOW BECOMING S-SE 10-15KTS THIS
AFTERNOON...ESPECIALLY SOUTH OF SEBASTIAN INLET...WITH DEVELOPMENT
OF EAST COAST SEA BREEZE. S-SW 10-15KT OVERNIGHT INTO SAT MORN. SEAS
2-3FT THIS MORNING...BECOMING 2FT LATER TODAY AND TONIGHT. DOMINANT
PERIODS REMAIN FAIRLY SHORT WITH OFFSHORE COMPONENT TO FLOW...AROUND
7-8 SEC. SOUTHERLY COMPONENT WILL CONTINUE TO LEAD TO BAHAMAS
SHADOWING SOUTH OF SEBASTIAN INLET WITH 3-5SEC.
SAT-TUE...SOUTHERLY WINDS WILL INCREASE TO 10-15KT AT TIMES OVER THE
WEEKEND...WITH SEAS 2 FT NEAR THE COAST AND AROUND 3 FT OFFSHORE.
SCATTERED SHOWERS AND STORMS ARE EXPECTED OVER THE WATERS. THE ATLC
RIDGE WILL LIFT SLOWLY NORTHWARD NEXT WEEK ALLOWING WINDS TO BECOME
SE MON-TUE. SEAS ARE FORECAST TO REMAIN AROUND 2 FT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 90 75 90 75 / 60 50 60 40
MCO 92 75 92 74 / 60 40 60 30
MLB 90 76 89 75 / 50 40 50 30
VRB 90 74 89 75 / 50 30 40 30
LEE 91 76 90 76 / 70 30 60 30
SFB 91 76 92 76 / 60 40 60 40
ORL 91 77 91 76 / 60 40 60 40
FPR 89 74 89 74 / 40 30 40 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1142 AM CDT FRI SEP 5 2014
.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
&&
.PREV DISCUSSION...
325 AM CDT
THE EMPHASIS OF THE FORECAST WAS SPENT ON THE FIRST 24 HOURS
WHICH PRESENT THUNDERSTORMS IN THE REGION TODAY...INCLUDING THE
POTENTIAL FOR SOME SEVERE STORMS THIS AFTERNOON...AND THEN RAIN
CHANCES THROUGH TONIGHT.
TODAY...
A VERY MILD...MUGGY...AND EVEN BREEZY EARLY MORNING ACROSS THE AREA
WITH SOME PARTS OF CHICAGO AT 80 DEGREES AS OF 3 AM. AREA DEW POINTS
ARE IN THE MID 70S...MATCHING THAT OF THE GULF SEABOARD THIS
MORNING. THIS SURFACE WARM SECTOR IN PLACE IS ASSOCIATED WITH A
1000MB LOW PRESSURE DEPARTING NORTHEASTWARD WITH ITS PARENT UPPER
TROUGH ACROSS ONTARIO THIS MORNING. THE ELONGATED SYSTEM COLD
FRONT WILL OOZE SOUTHEASTWARD REACHING NORTH CENTRAL IL DURING
MID-MORNING AND THE CHICAGO AREA AROUND NOONTIME...WHILE CLEARING
THE SOUTHEAST FORECAST AREA BY EARLY THIS EVENING.
WHILE THE REGIONAL RADAR THIS MORNING DOES SHOW A DECENT AMOUNT OF
CONVECTION IN IA AND EASTERN NE...MUCH OF THAT IS POST FRONTAL. ANY
SHOWERS OR STORMS BEFORE NOON WOULD LIKELY BE DUE TO A SUBTLE
MOISTENING IN THE VERY UNSTABLE LAYER ALOFT...WHICH THERE IS A
LITTLE BIT OF ON IR/11-3.9 MICRON SATELLITE IMAGERY. THIS TYPE OF
FORCING WOULD INDICATE ONLY ISOLATED IN COVERAGE IF DEVELOPMENT
WERE TO OCCUR.
WITH SURFACE HEATING AND ADVECTION OF EVEN HIGHER 0-1KM MIXING
RATIOS AHEAD OF THE FRONT DURING THE AFTERNOON...ADAPTED MODEL
SOUNDINGS LEAD TO FAIRLY HIGH CONFIDENCE THAT THE CAP WILL BE
BREACHED WITH SCATTERED STORMS ALONG THE COLD FRONT. DEPENDING ON
THE DEGREE OF HEATING...THIS COULD OCCUR ALREADY BY 12-2 PM. THIS
IS MOST FAVORED ALONG AND EAST OF INTERSTATE 55. LOOKING AT
HIGH-RES CONVECTIVE MODELS IN AN ENSEMBLE APPROACH /SPC
SSEO/...THERE ARE GOOD NEIGHBORHOOD VALUES OF HIGHER UPDRAFT SPEED
SUPPORTED BY HIGH INSTABILITY WITH MLCAPE IN EXCESS OF 3000 J/KG.
WITH LAGGING UPPER/MID-LEVEL FLOW TO THE FRONT...INSTABILITY WILL
BE THE DRIVER OF THESE STORMS AND THEIR INITIAL EVOLUTION.
EXPECTING A MODE THUS OF SOMEWHAT SLOW-MOVING CELLS OR MULTI-
CELLS WHICH SHOULD EVOLVE SOUTHEASTWARD THROUGH LATE
AFTERNOON/EARLY EVENING. A SCATTERED LARGE HAIL AND LOCALIZED
FLASH FLOODING THREAT WILL EXIST...AND WITH ANY MULTI-CELLS AN
ISOLATED SEVERE WIND THREAT...WITH THE LATTER LOOKING BETTER
FURTHER EAST AS STORM ORGANIZATION IS MORE FAVORED.
TONIGHT...
WHILE THE SURFACE FRONT WILL HAVE CLEARED THE FORECAST AREA BY OR
DURING EARLY EVENING...A SECOND STRONG UPPER SHORT WAVE ACROSS CO
EARLY THIS MORNING WILL TRACK NORTHEASTWARD ALONG THE 700-500MB
BAROCLINIC ZONE. THIS HAS BEEN CONSISTENTLY FORECAST IN THE REGION MY
MODELS FOR DAYS AND NOW OBSERVATIONAL SATELLITE TRENDS ARE
SUPPORTING THIS. THIS IS AN EARLY SIGN OF THE COOL SEASON...AS THIS
TYPE OF FORCING BEGINS TO SHOW UP MORE AND WILL EVENTUALLY
REPLACE THE VERTICAL INSTABILITY THAT WE ARE LOOK AT TODAY. BUT
NO NEED TO RUSH INTO THAT! SO BACK TO TONIGHT...A VERTICAL
FRONTAL CIRCULATION IS FORECAST WHICH WITH MOISTURE TRANSPORT AND
SATURATION IN THE MID-LEVELS SHOULD AT LEAST ALLOW LIKELY RAIN
IN THE REGION. THERE IS UNCERTAINTY ON HOW FAR NORTH RAIN THIS WILL
BE. ITS CERTAINLY PLAUSIBLE THAT EVEN THE NORTHERN CWA GETS INTO
THIS...WITH ROCKFORD AND CHICAGO HAVING A FEW HOUR PERIOD OF LIGHT
RAIN THIS EVENING INTO EARLY OVERNIGHT. ELEVATED INSTABILITY WILL
BE SLOW TO DEPART IN THE SOUTHERN FORECAST AREA SO CONTINUE
THUNDER CHANCES WITH MORE OF A MODERATE RAIN THERE. ADDITIONAL
RAINFALL AMOUNTS TONIGHT OF OVER ONE HALF INCH ARE FAVORED UNDER
ANY MORE SUSTAINED RAIN CORRIDORS THAT SET UP.
THIS WEEKEND...
NO REAL CHANGES MADE TO THIS PORTION OF THE FORECAST. LINGERING
ANAFRONTAL CLOUDS COULD CONTINUE SATURDAY MORNING BUT A CLEAR SKY IS
EXPECTED FOR THE REST OF THE WEEKEND. AFTERNOON TEMPERATURES IN
THE LOWER TO MID 70S...ABOUT 5 TO 7 DEGREES BELOW NORMAL...ARE
FORECAST. SURFACE WINDS SHOULD BECOME CALM EACH LATE EVENING AND
WITH DRIER AIR ADVECTION CONTINUING...WE UNDERCUT A MODEL FORECAST
BLEND FOR LOWS. SHOULD SEE OUTLYING AREAS REALIZE LOWS IN THE
UPPER 40S WITH COOL SPOTS POSSIBLY MID 40S.
NEXT WEEK...
CONTINUED QUASI-ZONAL UPPER FLOW ACROSS THE NORTHERN U.S. AT THE
FAR SOUTHERN BASE OF A COLD CANADIAN TROUGH IS FORECAST NEXT WEEK.
RETURN LOW-LEVEL LOW RESUMES EARLY IN THE WORKWEEK...BUT
MOISTENING LOOKS SLOW. GIVEN THAT AND THE FACT ANY FORCING
MECHANISMS LOOK TO BE LOW AMPLITUDE...SPREAD POPS IN SLOWER THAN
GUIDANCE MONDAY NIGHT-TUESDAY NIGHT. NOT SURPRISING TO SEE A LARGE
MODEL SPREAD IN SPECIFICS DURING THE MIDDLE OF NEXT WEEK...BUT
RIGHT NOW SOMETIME IN THE WEDNESDAY-THURSDAY PERIOD A STRONGER
SHORT WAVE TROUGH IS FORECAST TO PASS...WHICH CONCEIVABLY WOULD
BRING THE GREATER RAIN CHANCES TO THE REGION.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* TIMING/COVERAGE OF TSRA TODAY.
* WIND SHIFT FROM SW TO NW WITH COLD FRONT THIS AFTN.
* POTENTIAL FOR MVFR CIGS THIS AFTN/TONIGHT.
RATZER/IZZI
//DISCUSSION...UPDATED 12Z...
COLD FRONT STRETCHES FROM EAST CENTRAL WI TO EASTERN IA THIS
MORNING. ISOLATED SHRA/TSRA POSSIBLE IN WARM/MOIST SOUTHWEST FLOW
AHEAD OF THE FRONT THIS MORNING...THOUGH LITTLE TO FOCUS
WIDESPREAD DEVELOPMENT EXPECTED UNTIL SURFACE COLD FRONT
APPROACHES AND TIMING OF COLD FROPA STILL APPEARS TO BE AROUND
15Z FOR KRFD AND 19-20Z FOR KORD/KMDW. THE GREATEST POTENTIAL FOR
TSRA WILL BE THIS AFTERNOON ALONG/AHEAD OF THE FRONT...WITH HIGH-
RES MODEL GUIDANCE INDICATING TSRA INITIATION NEAR OR SOUTHEAST OF
CHICAGO. TSRA THREAT SHOULD MOVE SOUTHEAST OF TERMINALS BY LATE
AFTERNOON AS THE FRONT CONTINUES TO PUSH SOUTHEAST. MVFR CIGS
POSSIBLE IN SHRA/TSRA...AND ALSO FOR A PERIOD BEHIND THE FRONT
THIS AFTERNOON. SHOWERS/RAIN EXPECTED TO REDEVELOP ACROSS THE
TERMINALS THIS EVENING WITH FURTHER MVFR CIG POTENTIAL AS AN
UPPER DISTURBANCE PROPAGATES ACROSS THE AREA. EXPECTATION IS FOR
CIGS TO BE IN 2000-3000 FT RANGE. DRIER AIR FINALLY MOVES IN EARLY
SATURDAY MORNING WITH VFR CONDITIONS.
SOUTHWEST WINDS AROUND 10 KT THIS MORNING AHEAD OF THE FRONT WILL
SHIFT MORE WEST-SOUTHWEST WITH TIME...THEN NORTHWEST BEHIND THE
FRONT. SOME GUIDANCE INDICATES WINDS MAY BECOME MORE NORTH OR EVEN
NORTH-NORTHEAST BRIEFLY THIS AFTERNOON...BUT LIKELY TO HOLD OFF
UNTIL LATE TONIGHT/SATURDAY.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* LOW-MEDIUM IN TSRA/MVFR CIGS.
* HIGH FOR WINDS AND OTHER FORECAST ELEMENTS.
RATZER/IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT THROUGH MONDAY...VFR. SLGT CHC TSRA MONDAY NIGHT.
TUESDAY AND WEDNESDAY...CHC OF PERIODIC TSRA. MVFR CIGS PSBL.
THURSDAY...CHC OF SHOWERS. MVFR CIGS PSBL.
RATZER
&&
.MARINE...
314 AM CDT
LOW PRESSURE WAS NORTH OF LAKE SUPERIOR EARLY THIS MORNING...WITH A
COLD FRONT TRAILING SOUTHWEST ACROSS WISCONSIN AND EASTERN IOWA.
THIS LOW WILL TRACK TO THE NORTHEAST WHILE CONTINUING TO DEEPEN
TODAY WHILE THE FRONT PUSHES SOUTHEAST ACROSS THE LAKE THROUGH THIS
AFTERNOON. SURFACE PRESSURE FALLS AND A RELATIVELY TIGHT PRESSURE
GRADIENT AHEAD OF THE FRONT AND ASSOCIATED WITH THE DEEPENING LOW
HAS LED TO SOUTH-SOUTHWEST WINDS IN THE 25-30 KT RANGE OVERNIGHT.
WINDS SHOULD GRADUALLY EASE INTO THE 15-25 KT RANGE AS THE GRADIENT
WEAKENS IN PROXIMITY TO THE COLD FRONTAL TROUGH LATER THIS MORNING
AND THIS AFTERNOON...VEERING TO THE NORTHWEST AND EVENTUALLY NORTH
BEHIND THE FRONT TONIGHT. SURFACE HIGH PRESSURE WILL THEN BUILD
SOUTHEAST ACROSS THE PLAINS...AND EAST ACROSS THE SOUTHERN GREAT
LAKES TONIGHT AND SATURDAY WHILE A SECOND WEAK COLD FRONT SETTLES
ACROSS THE NORTHERN LAKES. NORTH-NORTHWEST WINDS ARE EXPECTED TO
REMAIN IN THE 15-20 KT RANGE WITH A FEW GUSTS TO 25 KT POSSIBLE INTO
EARLY SATURDAY AS COOL AIR BUILDS IN WITH THE HIGH...THEN SLACKEN
SATURDAY NIGHT AND SUNDAY AS THE HIGH MOVES EAST ACROSS THE LAKES.
BY MONDAY THE HIGH WILL SHIFT OVER THE ST LAWRENCE VALLEY...WHILE
LOW PRESSURE DEVELOPS ACROSS THE NORTHERN PLAINS. THIS WILL ALLOW
WINDS TO SHIFT BACK TO THE SOUTH EARLY NEXT WEEK...WITH THE PLAINS
LOW EVENTUALLY APPROACHING THE GREAT LAKES MID-WEEK.
FOR THE ILLINOIS/NORTHWEST INDIANA NEARSHORE WATERS...SOME GUSTS
NEAR 30 KT NOTED FROM HIGH-MOUNTED WIND MEASURING EQUIPMENT THIS
MORNING BUT WITH RELATIVELY LOW WAVES IN OFFSHORE FLOW. NORTHERLY
FETCH LATER TONIGHT AND SATURDAY LOOKS TO PRODUCE MARGINAL SMALL
CRAFT ADVISORY CONDITIONS.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1053 AM CDT Fri Sep 5 2014
.UPDATE...
ISSUED AT 1047 AM CDT FRI SEP 5 2014
Cold front approaching the region and some scattered showers
popped up this morning on the nose of the llvl jet early...and
were gone. More showers and thunderstorms are possible into the
afternoon as the front approaches and just behind it. Until
then...hot and muggy conditions expected to continue with
southwesterly winds. Heat indices are expected to climb into the mid
90s and near 100 south of Interstate 70. Minor tweaks to the
forecast grids, but no major changes.
&&
.SHORT TERM...(Today)
ISSUED AT 328 AM CDT FRI SEP 5 2014
Cold front beginning to edge into east central Iowa early this
morning with most models pushing the boundary across our area during
the afternoon and early evening hours. One more hot and humid day
ahead of the cold front with temperatures ranging from the upper
80s far northwest to the lower 90s east central through southeast
Illinois. Forecast soundings showing the warm layer extending from
850-700 mb will gradually erode with time today which should allow
better coverage of convection along the frontal boundary despite
rather weak convergence. However, most models depict some robust
CAPES this afternoon with 3500-4500 J/KG forecast over central thru
east central Illinois. 0-6km bulk shear not very impressive until
you get behind the cold front, otherwise, most models indicate bulk
shear values of 15-20 kts in the warm section just ahead of the
front. Precipitable water values of around 2 inches still forecast
this afternoon so any storms that organize will produce torrential
rainfall in a short period of time, in addition to the possibility
for an isolated strong wind gust/wet microburst. Most of the
convective allowing models suggest the stronger convection will
begin to push into Indiana by late this afternoon or early this
evening and then begin to weaken.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 328 AM CDT FRI SEP 5 2014
Cold front passes southeast of CWA this evening, while 00Z models
have trended slower with mid/upper level system/forcing tonight
into Saturday morning with showers and isolated thunderstorms likely
lingering overnight and over southern half from I-72 south Saturday
morning. Lows tonight to range from upper 50s and lower 60s over IL
river valley to upper 60s southeast of I-70 where muggy conditions
linger through tonight. North winds to advect in cooler and less
humid air during the day Saturday as clouds decrease from nw to se
Saturday afternoon. Much cooler highs in the mid 70s Saturday as
1022 mb high pressure over the northern Rockies settles east into
the central plains. This high pressure will settle over IL and
southern great lakes Sunday and keep cooler and less humid air in
place. Lows Saturday and Sunday night in low to mid 50s with a few
upper 40s over a few spots from I-74 ne. A fair amount of sunshine
Sunday with highs in the mid to upper 70s and comfortable dewpoints
in the low to mid 50s. Another nice day in store Monday as high
pressure settles into New England and clouds increase from the west
over IL ahead of next weather system. Highs in the upper 70s central
IL and near 80F south of I-70.
Unsettled weather pattern taking shape from Monday night through
Thu. Weather system spread qpf into IL from west to east during
Monday night into Tue and models have trended faster with this
feature so have increased pops. A stronger weather system arriving
Wed/Thu time frame as surface low pressure deepens ne from the
southern plains into the great lakes. Expect increased chances of
showers and a few thunderstorms. Then much cooler temperatures
arrive by next Friday and Friday night.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 605 AM CDT FRI SEP 5 2014
A cold front over east central Iowa will push into our area early
this afternoon and bring the threat for scattered showers and
thunderstorms to central through east central Illinois into early
this evening. Other than some patchy fog early this morning which
may produce a brief period of MVFR vsbys, VFR conditions are expected
into this evening. Forecast soundings and time height cross sections
indicate that as the cooler air arrives later this evening, it may be
accompanied by some MVFR or possibly IFR cigs in the 08z-12z time
frame. Not seeing a lot of evidence of widespread MVFR or lower cigs
behind the cold front at this time, so will only introduce a scattered
cloud below 1000 feet late in the period with a prevailing cig above
that at 3500-4000 feet. Coverage of storms this afternoon near the
front scattered at best with the latest HRRR model suggesting areas
along and southeast of a Danville to Lincoln to Jacksonville line
having a better chance for seeing convection into early this evening.
For this reason, will continue with the tempo groups at KCMI, KDEC
and KSPI, with VCTS further north at KBMI and KPIA where it appears
coverage of storms will be less.
It appears there may be a break in the convection early this evening
with a round of showers moving in late tonight into Saturday morning
as a weak area of low pressure drifts east along the slow moving cold
front, which by this time, should be south of our area. Will carry
a VCSH for later this evening across most of our area and keep an eye
on the lowering cigs. Surface winds ahead of the front will be out
of the southwest at 10 to 15 kts, then become westerly along the
boundary, and with the FROPA, winds should shift to a northwest
to north direction by late afternoon and early evening with speeds
running from 8 to 13 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...SMITH
LONG TERM...07
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
654 AM CDT FRI SEP 5 2014
.DISCUSSION...
325 AM CDT
THE EMPHASIS OF THE FORECAST WAS SPENT ON THE FIRST 24 HOURS
WHICH PRESENT THUNDERSTORMS IN THE REGION TODAY...INCLUDING THE
POTENTIAL FOR SOME SEVERE STORMS THIS AFTERNOON...AND THEN RAIN
CHANCES THROUGH TONIGHT.
TODAY...
A VERY MILD...MUGGY...AND EVEN BREEZY EARLY MORNING ACROSS THE AREA
WITH SOME PARTS OF CHICAGO AT 80 DEGREES AS OF 3 AM. AREA DEW POINTS
ARE IN THE MID 70S...MATCHING THAT OF THE GULF SEABOARD THIS
MORNING. THIS SURFACE WARM SECTOR IN PLACE IS ASSOCIATED WITH A
1000MB LOW PRESSURE DEPARTING NORTHEASTWARD WITH ITS PARENT UPPER
TROUGH ACROSS ONTARIO THIS MORNING. THE ELONGATED SYSTEM COLD
FRONT WILL OOZE SOUTHEASTWARD REACHING NORTH CENTRAL IL DURING
MID-MORNING AND THE CHICAGO AREA AROUND NOONTIME...WHILE CLEARING
THE SOUTHEAST FORECAST AREA BY EARLY THIS EVENING.
WHILE THE REGIONAL RADAR THIS MORNING DOES SHOW A DECENT AMOUNT OF
CONVECTION IN IA AND EASTERN NE...MUCH OF THAT IS POST FRONTAL. ANY
SHOWERS OR STORMS BEFORE NOON WOULD LIKELY BE DUE TO A SUBTLE
MOISTENING IN THE VERY UNSTABLE LAYER ALOFT...WHICH THERE IS A
LITTLE BIT OF ON IR/11-3.9 MICRON SATELLITE IMAGERY. THIS TYPE OF
FORCING WOULD INDICATE ONLY ISOLATED IN COVERAGE IF DEVELOPMENT
WERE TO OCCUR.
WITH SURFACE HEATING AND ADVECTION OF EVEN HIGHER 0-1KM MIXING
RATIOS AHEAD OF THE FRONT DURING THE AFTERNOON...ADAPTED MODEL
SOUNDINGS LEAD TO FAIRLY HIGH CONFIDENCE THAT THE CAP WILL BE
BREACHED WITH SCATTERED STORMS ALONG THE COLD FRONT. DEPENDING ON
THE DEGREE OF HEATING...THIS COULD OCCUR ALREADY BY 12-2 PM. THIS
IS MOST FAVORED ALONG AND EAST OF INTERSTATE 55. LOOKING AT
HIGH-RES CONVECTIVE MODELS IN AN ENSEMBLE APPROACH /SPC
SSEO/...THERE ARE GOOD NEIGHBORHOOD VALUES OF HIGHER UPDRAFT SPEED
SUPPORTED BY HIGH INSTABILITY WITH MLCAPE IN EXCESS OF 3000 J/KG.
WITH LAGGING UPPER/MID-LEVEL FLOW TO THE FRONT...INSTABILITY WILL
BE THE DRIVER OF THESE STORMS AND THEIR INITIAL EVOLUTION.
EXPECTING A MODE THUS OF SOMEWHAT SLOW-MOVING CELLS OR MULTI-
CELLS WHICH SHOULD EVOLVE SOUTHEASTWARD THROUGH LATE
AFTERNOON/EARLY EVENING. A SCATTERED LARGE HAIL AND LOCALIZED
FLASH FLOODING THREAT WILL EXIST...AND WITH ANY MULTI-CELLS AN
ISOLATED SEVERE WIND THREAT...WITH THE LATTER LOOKING BETTER
FURTHER EAST AS STORM ORGANIZATION IS MORE FAVORED.
TONIGHT...
WHILE THE SURFACE FRONT WILL HAVE CLEARED THE FORECAST AREA BY OR
DURING EARLY EVENING...A SECOND STRONG UPPER SHORT WAVE ACROSS CO
EARLY THIS MORNING WILL TRACK NORTHEASTWARD ALONG THE 700-500MB
BAROCLINIC ZONE. THIS HAS BEEN CONSISTENTLY FORECAST IN THE REGION MY
MODELS FOR DAYS AND NOW OBSERVATIONAL SATELLITE TRENDS ARE
SUPPORTING THIS. THIS IS AN EARLY SIGN OF THE COOL SEASON...AS THIS
TYPE OF FORCING BEGINS TO SHOW UP MORE AND WILL EVENTUALLY
REPLACE THE VERTICAL INSTABILITY THAT WE ARE LOOK AT TODAY. BUT
NO NEED TO RUSH INTO THAT! SO BACK TO TONIGHT...A VERTICAL
FRONTAL CIRCULATION IS FORECAST WHICH WITH MOISTURE TRANSPORT AND
SATURATION IN THE MID-LEVELS SHOULD AT LEAST ALLOW LIKELY RAIN
IN THE REGION. THERE IS UNCERTAINTY ON HOW FAR NORTH RAIN THIS WILL
BE. ITS CERTAINLY PLAUSIBLE THAT EVEN THE NORTHERN CWA GETS INTO
THIS...WITH ROCKFORD AND CHICAGO HAVING A FEW HOUR PERIOD OF LIGHT
RAIN THIS EVENING INTO EARLY OVERNIGHT. ELEVATED INSTABILITY WILL
BE SLOW TO DEPART IN THE SOUTHERN FORECAST AREA SO CONTINUE
THUNDER CHANCES WITH MORE OF A MODERATE RAIN THERE. ADDITIONAL
RAINFALL AMOUNTS TONIGHT OF OVER ONE HALF INCH ARE FAVORED UNDER
ANY MORE SUSTAINED RAIN CORRIDORS THAT SET UP.
THIS WEEKEND...
NO REAL CHANGES MADE TO THIS PORTION OF THE FORECAST. LINGERING
ANAFRONTAL CLOUDS COULD CONTINUE SATURDAY MORNING BUT A CLEAR SKY IS
EXPECTED FOR THE REST OF THE WEEKEND. AFTERNOON TEMPERATURES IN
THE LOWER TO MID 70S...ABOUT 5 TO 7 DEGREES BELOW NORMAL...ARE
FORECAST. SURFACE WINDS SHOULD BECOME CALM EACH LATE EVENING AND
WITH DRIER AIR ADVECTION CONTINUING...WE UNDERCUT A MODEL FORECAST
BLEND FOR LOWS. SHOULD SEE OUTLYING AREAS REALIZE LOWS IN THE
UPPER 40S WITH COOL SPOTS POSSIBLY MID 40S.
NEXT WEEK...
CONTINUED QUASI-ZONAL UPPER FLOW ACROSS THE NORTHERN U.S. AT THE
FAR SOUTHERN BASE OF A COLD CANADIAN TROUGH IS FORECAST NEXT WEEK.
RETURN LOW-LEVEL LOW RESUMES EARLY IN THE WORKWEEK...BUT
MOISTENING LOOKS SLOW. GIVEN THAT AND THE FACT ANY FORCING
MECHANISMS LOOK TO BE LOW AMPLITUDE...SPREAD POPS IN SLOWER THAN
GUIDANCE MONDAY NIGHT-TUESDAY NIGHT. NOT SURPRISING TO SEE A LARGE
MODEL SPREAD IN SPECIFICS DURING THE MIDDLE OF NEXT WEEK...BUT
RIGHT NOW SOMETIME IN THE WEDNESDAY-THURSDAY PERIOD A STRONGER
SHORT WAVE TROUGH IS FORECAST TO PASS...WHICH CONCEIVABLY WOULD
BRING THE GREATER RAIN CHANCES TO THE REGION.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* TIMING/COVERAGE OF TSRA TODAY.
* WIND SHIFT FROM SW TO NW WITH COLD FRONT THIS AFTN.
* POTENTIAL FOR MVFR CIGS BEHIND COLD FRONT AND WITH PCPN THIS
AFTN/TONIGHT.
RATZER
//DISCUSSION...UPDATED 12Z...
COLD FRONT STRETCHES FROM EAST CENTRAL WI TO EASTERN IA THIS
MORNING. ISOLATED SHRA/TSRA POSSIBLE IN WARM/MOIST SOUTHWEST FLOW
AHEAD OF THE FRONT THIS MORNING...THOUGH LITTLE TO FOCUS
WIDESPREAD DEVELOPMENT EXPECTED UNTIL SURFACE COLD FRONT
APPROACHES AND TIMING OF COLD FROPA STILL APPEARS TO BE AROUND
15Z FOR KRFD AND 19-20Z FOR KORD/KMDW. THE GREATEST POTENTIAL FOR
TSRA WILL BE THIS AFTERNOON ALONG/AHEAD OF THE FRONT...WITH HIGH-
RES MODEL GUIDANCE INDICATING TSRA INITIATION NEAR OR SOUTHEAST OF
CHICAGO. TSRA THREAT SHOULD MOVE SOUTHEAST OF TERMINALS BY LATE
AFTERNOON AS THE FRONT CONTINUES TO PUSH SOUTHEAST. MVFR CIGS
POSSIBLE IN SHRA/TSRA...AND ALSO FOR A PERIOD BEHIND THE FRONT
THIS AFTERNOON. SHOWERS/RAIN EXPECTED TO REDEVELOP ACROSS THE
TERMINALS THIS EVENING WITH FURTHER MVFR CIG POTENTIAL AS AN
UPPER DISTURBANCE PROPAGATES ACROSS THE AREA. EXPECTATION IS FOR
CIGS TO BE IN 2000-3000 FT RANGE. DRIER AIR FINALLY MOVES IN EARLY
SATURDAY MORNING WITH VFR CONDITIONS.
SOUTHWEST WINDS AROUND 10 KT THIS MORNING AHEAD OF THE FRONT WILL
SHIFT MORE WEST-SOUTHWEST WITH TIME...THEN NORTHWEST BEHIND THE
FRONT. SOME GUIDANCE INDICATES WINDS MAY BECOME MORE NORTH OR EVEN
NORTH-NORTHEAST BRIEFLY THIS AFTERNOON...BUT LIKELY TO HOLD OFF
UNTIL LATE TONIGHT/SATURDAY.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM IN TSRA/MVFR CIGS.
* HIGH FOR WINDS AND OTHER FORECAST ELEMENTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT THROUGH MONDAY...VFR. SLGT CHC TSRA MONDAY NIGHT.
TUESDAY AND WEDNESDAY...CHC OF PERIODIC TSRA. MVFR CIGS PSBL.
THURSDAY...CHC OF SHOWERS. MVFR CIGS PSBL.
RATZER
&&
.MARINE...
314 AM CDT
LOW PRESSURE WAS NORTH OF LAKE SUPERIOR EARLY THIS MORNING...WITH A
COLD FRONT TRAILING SOUTHWEST ACROSS WISCONSIN AND EASTERN IOWA.
THIS LOW WILL TRACK TO THE NORTHEAST WHILE CONTINUING TO DEEPEN
TODAY WHILE THE FRONT PUSHES SOUTHEAST ACROSS THE LAKE THROUGH THIS
AFTERNOON. SURFACE PRESSURE FALLS AND A RELATIVELY TIGHT PRESSURE
GRADIENT AHEAD OF THE FRONT AND ASSOCIATED WITH THE DEEPENING LOW
HAS LED TO SOUTH-SOUTHWEST WINDS IN THE 25-30 KT RANGE OVERNIGHT.
WINDS SHOULD GRADUALLY EASE INTO THE 15-25 KT RANGE AS THE GRADIENT
WEAKENS IN PROXIMITY TO THE COLD FRONTAL TROUGH LATER THIS MORNING
AND THIS AFTERNOON...VEERING TO THE NORTHWEST AND EVENTUALLY NORTH
BEHIND THE FRONT TONIGHT. SURFACE HIGH PRESSURE WILL THEN BUILD
SOUTHEAST ACROSS THE PLAINS...AND EAST ACROSS THE SOUTHERN GREAT
LAKES TONIGHT AND SATURDAY WHILE A SECOND WEAK COLD FRONT SETTLES
ACROSS THE NORTHERN LAKES. NORTH-NORTHWEST WINDS ARE EXPECTED TO
REMAIN IN THE 15-20 KT RANGE WITH A FEW GUSTS TO 25 KT POSSIBLE INTO
EARLY SATURDAY AS COOL AIR BUILDS IN WITH THE HIGH...THEN SLACKEN
SATURDAY NIGHT AND SUNDAY AS THE HIGH MOVES EAST ACROSS THE LAKES.
BY MONDAY THE HIGH WILL SHIFT OVER THE ST LAWRENCE VALLEY...WHILE
LOW PRESSURE DEVELOPS ACROSS THE NORTHERN PLAINS. THIS WILL ALLOW
WINDS TO SHIFT BACK TO THE SOUTH EARLY NEXT WEEK...WITH THE PLAINS
LOW EVENTUALLY APPROACHING THE GREAT LAKES MID-WEEK.
FOR THE ILLINOIS/NORTHWEST INDIANA NEARSHORE WATERS...SOME GUSTS
NEAR 30 KT NOTED FROM HIGH-MOUNTED WIND MEASURING EQUIPMENT THIS
MORNING BUT WITH RELATIVELY LOW WAVES IN OFFSHORE FLOW. NORTHERLY
FETCH LATER TONIGHT AND SATURDAY LOOKS TO PRODUCE MARGINAL SMALL
CRAFT ADVISORY CONDITIONS.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
608 AM CDT Fri Sep 5 2014
.SHORT TERM...(Today)
ISSUED AT 328 AM CDT FRI SEP 5 2014
Cold front beginning to edge into east central Iowa early this
morning with most models pushing the boundary across our area during
the afternoon and early evening hours. One more hot and humid day
ahead of the cold front with temperatures ranging from the upper
80s far northwest to the lower 90s east central through southeast
Illinois. Forecast soundings showing the warm layer extending from
850-700 mb will gradually erode with time today which should allow
better coverage of convection along the frontal boundary despite
rather weak convergence. However, most models depict some robust
CAPES this afternoon with 3500-4500 J/KG forecast over central thru
east central Illinois. 0-6km bulk shear not very impressive until
you get behind the cold front, otherwise, most models indicate bulk
shear values of 15-20 kts in the warm section just ahead of the
front. Precipitable water values of around 2 inches still forecast
this afternoon so any storms that organize will produce torrential
rainfall in a short period of time, in addition to the possibility
for an isolated strong wind gust/wet microburst. Most of the
convective allowing models suggest the stronger convection will
begin to push into Indiana by late this afternoon or early this
evening and then begin to weaken.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 328 AM CDT FRI SEP 5 2014
Cold front passes southeast of CWA this evening, while 00Z models
have trended slower with mid/upper level system/forcing tonight
into Saturday morning with showers and isolated thunderstorms likely
lingering overnight and over southern half from I-72 south Saturday
morning. Lows tonight to range from upper 50s and lower 60s over IL
river valley to upper 60s southeast of I-70 where muggy conditions
linger through tonight. North winds to advect in cooler and less
humid air during the day Saturday as clouds decrease from nw to se
Saturday afternoon. Much cooler highs in the mid 70s Saturday as
1022 mb high pressure over the northern Rockies settles east into
the central plains. This high pressure will settle over IL and
southern great lakes Sunday and keep cooler and less humid air in
place. Lows Saturday and Sunday night in low to mid 50s with a few
upper 40s over a few spots from I-74 ne. A fair amount of sunshine
Sunday with highs in the mid to upper 70s and comfortable dewpoints
in the low to mid 50s. Another nice day in store Monday as high
pressure settles into New England and clouds increase from the west
over IL ahead of next weather system. Highs in the upper 70s central
IL and near 80F south of I-70.
Unsettled weather pattern taking shape from Monday night through
Thu. Weather system spread qpf into IL from west to east during
Monday night into Tue and models have trended faster with this
feature so have increased pops. A stronger weather system arriving
Wed/Thu time frame as surface low pressure deepens ne from the
southern plains into the great lakes. Expect increased chances of
showers and a few thunderstorms. Then much cooler temperatures
arrive by next Friday and Friday night.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 605 AM CDT FRI SEP 5 2014
A cold front over east central Iowa will push into our area early
this afternoon and bring the threat for scattered showers and
thunderstorms to central through east central Illinois into early
this evening. Other than some patchy fog early this morning which
may produce a brief period of MVFR vsbys, VFR conditions are expected
into this evening. Forecast soundings and time height cross sections
indicate that as the cooler air arrives later this evening, it may be
accompanied by some MVFR or possibly IFR cigs in the 08z-12z time
frame. Not seeing a lot of evidence of widespread MVFR or lower cigs
behind the cold front at this time, so will only introduce a scattered
cloud below 1000 feet late in the period with a prevailing cig above
that at 3500-4000 feet. Coverage of storms this afternoon near the
front scattered at best with the latest HRRR model suggesting areas
along and southeast of a Danville to Lincoln to Jacksonville line
having a better chance for seeing convection into early this evening.
For this reason, will continue with the tempo groups at KCMI, KDEC
and KSPI, with VCTS further north at KBMI and KPIA where it appears
coverage of storms will be less.
It appears there may be a break in the convection early this evening
with a round of showers moving in late tonight into Saturday morning
as a weak area of low pressure drifts east along the slow moving cold
front, which by this time, should be south of our area. Will carry
a VCSH for later this evening across most of our area and keep an eye
on the lowering cigs. Surface winds ahead of the front will be out
of the southwest at 10 to 15 kts, then become westerly along the
boundary, and with the FROPA, winds should shift to a northwest
to north direction by late afternoon and early evening with speeds
running from 8 to 13 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SMITH
LONG TERM...07
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
216 PM EDT FRI SEP 5 2014
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 955 AM EDT FRI SEP 5 2014
.UPDATE...CURRENT FORECAST IS ON TRACK AND ONLY MINOR CHANGES MADE
WITH THIS UPDATE...MAINLY TO RAISE POPS SLIGHTLY OVER FAR NORTHERN
SECTIONS AS SHOWERS AND THUNDERSTORMS WERE ALREADY OVER NORTHEAST
ILLINOIS WHICH MAY BRUSH FAR NORTHERN AREAS IN A FEW HOURS.
PORTION OF PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MOST CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST
AREA ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN
GREAT LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND
A SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE
TO THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 213 PM EDT FRI SEP 5 2014
MOSTLY ZONAL FLOW EARLY IN THE LONG TERM WILL GIVE WAY TO A BROAD
TROUGH OVER MUCH OF THE U.S. WHICH WILL ALLOW TEMPERATURES TO REMAIN
COOLER THAN NORMAL THROUGHOUT THE LONG TERM PERIOD. HIGH PRESSURE
DEPARTING TO THE EAST MONDAY NIGHT WILL COINCIDE WITH A FRONTAL
SYSTEM FORMING OVER THE CENTRAL U.S. AND SLOWLY MOVING ACROSS THE
AREA BRINGING CHANCES FOR THUNDERSTORMS INTO THE FORECAST TUESDAY
THROUGH THURSDAY. MODEL DIFFERENCES IN TIMING OF THE EXIT OF THE
SYSTEM MEAN KEEPING CHANCES IN THROUGH THURSDAY NIGHT...BUT BY
FRIDAY MOST EVERYTHING HAS THE SYSTEM OUT OF THE AREA AND HIGH
PRESSURE BUILDING IN BEHIND IT.
&&
.AVIATION /DISCUSSION FOR 051800Z TAF ISSUANCE/...
ISSUED AT 1249 PM EDT FRI SEP 5 2014
CAPPING INVERSION IS STILL IN PLACE OVER THE SITES AND WITH HIGH
CONVECTIVE TEMPERATURES THIS SHOULD INHIBIT CONVECTION TOO FAR AHEAD
OF THE COLD FRONT. THUS WILL PUSH BACK TIMING OF CONVECTION BY A
COUPLE HOURS WITH VCTS AT KLAF AFTER 21Z AND EXPLICIT THUNDER AT
23Z. STILL ANTICIPATE A LINE OF THUNDERSTORMS MOVING SOUTHEAST
THROUGH THE SITES...ALTHOUGH THERE IS INCREASING UNCERTAINTY ABOUT
HOW FAR SOUTH THE LINE WILL REACH WITH THE UPPER FORCING STAYING
TO THE NORTH. GUIDANCE IS INDICATING LOW CEILINGS AFTER FRONTAL
PASSAGE AND SOME LIGHT SHOWERS OR DRIZZLE AND THINK THIS LOOKS
REASONABLE. THUS AFTER BEING VFR THROUGH AROUND 0Z OR MORE SHOULD
SEE DETERIORATING FLYING CONDITIONS DURING THE NIGHT WHICH MAY NOT
IMPROVE UNTIL SATURDAY AFTERNOON OR EVENING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....CP
AVIATION...CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
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WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1251 PM EDT FRI SEP 5 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 955 AM EDT FRI SEP 5 2014
.UPDATE...CURRENT FORECAST IS ON TRACK AND ONLY MINOR CHANGES MADE
WITH THIS UPDATE...MAINLY TO RAISE POPS SLIGHTLY OVER FAR NORTHERN
SECTIONS AS SHOWERS AND THUNDERSTORMS WERE ALREADY OVER NORTHEAST
ILLINOIS WHICH MAY BRUSH FAR NORTHERN AREAS IN A FEW HOURS.
PORTION OF PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MOST CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST
AREA ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN
GREAT LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND
A SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE
TO THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 342 AM EDT FRI SEP 5 2014
DRY CONDITIONS CAN BE EXPECTED ON MONDAY WITH ZONAL FLOW ALOFT AND
WEAK HIGH PRESSURE STILL AT THE SURFACE. HOWEVER...THE PATTERN WILL
QUICKLY SHIFT BY TUESDAY AS A BROAD UPPER TROUGH ENTERS THE AREA.
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS CENTRAL
INDIANA AS EARLY AS TUESDAY MORNING...WITH INCREASING CHANCES
THROUGH THE COURSE OF THE EXTENDED PERIOD AS A COLD FRONT TRACKS
ACROSS THE AREA ON WEDNESDAY NIGHT/THURSDAY. PRECIP CHANCES WILL
TAPER OFF TOWARD THE END OF THE PERIOD...BUT WILL KEEP MENTION OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH THURSDAY NIGHT TO
ACCOUNT FOR PASSAGE OF UPPER LOW. TEMPS WILL CONTINUE TO DROP WELL
BELOW NORMAL THROUGH THE COURSE OF THE EXTENDED PERIOD WITH HIGH
TEMPS ONLY IN THE UPPER 60S/LOW 70S BY FRIDAY.
&&
.AVIATION /DISCUSSION FOR 051800Z TAF ISSUANCE/...
ISSUED AT 1249 PM EDT FRI SEP 5 2014
CAPPING INVERSION IS STILL IN PLACE OVER THE SITES AND WITH HIGH
CONVECTIVE TEMPERATURES THIS SHOULD INHIBIT CONVECTION TOO FAR AHEAD
OF THE COLD FRONT. THUS WILL PUSH BACK TIMING OF CONVECTION BY A
COUPLE HOURS WITH VCTS AT KLAF AFTER 21Z AND EXPLICIT THUNDER AT
23Z. STILL ANTICIPATE A LINE OF THUNDERSTORMS MOVING SOUTHEAST
THROUGH THE SITES...ALTHOUGH THERE IS INCREASING UNCERTAINTY ABOUT
HOW FAR SOUTH THE LINE WILL REACH WITH THE UPPER FORCING STAYING
TO THE NORTH. GUIDANCE IS INDICATING LOW CEILINGS AFTER FRONTAL
PASSAGE AND SOME LIGHT SHOWERS OR DRIZZLE AND THINK THIS LOOKS
REASONABLE. THUS AFTER BEING VFR THROUGH AROUND 0Z OR MORE SHOULD
SEE DETERIORATING FLYING CONDITIONS DURING THE NIGHT WHICH MAY NOT
IMPROVE UNTIL SATURDAY AFTERNOON OR EVENING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1015 AM EDT FRI SEP 5 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 955 AM EDT FRI SEP 5 2014
.UPDATE...CURRENT FORECAST IS ON TRACK AND ONLY MINOR CHANGES MADE
WITH THIS UPDATE...MAINLY TO RAISE POPS SLIGHTLY OVER FAR NORTHERN
SECTIONS AS SHOWERS AND THUNDERSTORMS WERE ALREADY OVER NORTHEAST
ILLINOIS WHICH MAY BRUSH FAR NORTHERN AREAS IN A FEW HOURS.
PORTION OF PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MOST CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST
AREA ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN
GREAT LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND
A SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE
TO THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 342 AM EDT FRI SEP 5 2014
DRY CONDITIONS CAN BE EXPECTED ON MONDAY WITH ZONAL FLOW ALOFT AND
WEAK HIGH PRESSURE STILL AT THE SURFACE. HOWEVER...THE PATTERN WILL
QUICKLY SHIFT BY TUESDAY AS A BROAD UPPER TROUGH ENTERS THE AREA.
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS CENTRAL
INDIANA AS EARLY AS TUESDAY MORNING...WITH INCREASING CHANCES
THROUGH THE COURSE OF THE EXTENDED PERIOD AS A COLD FRONT TRACKS
ACROSS THE AREA ON WEDNESDAY NIGHT/THURSDAY. PRECIP CHANCES WILL
TAPER OFF TOWARD THE END OF THE PERIOD...BUT WILL KEEP MENTION OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH THURSDAY NIGHT TO
ACCOUNT FOR PASSAGE OF UPPER LOW. TEMPS WILL CONTINUE TO DROP WELL
BELOW NORMAL THROUGH THE COURSE OF THE EXTENDED PERIOD WITH HIGH
TEMPS ONLY IN THE UPPER 60S/LOW 70S BY FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 05/1500Z TAF ISSUANCE/...
ISSUED AT 1015 AM EDT FRI SEP 5 2014
FOR THE UPDATE...MOVED UP THE TIMING OF VCTS AT KIND AND ADDED A
TEMPO GROUP FOR THUNDERSTORMS AT KLAF DUE TO LINE OF SHOWERS AND
STORMS ALREADY OVER CENTRAL/NORTHEASTERN ILLINOIS MOVING EAST INTO
THE AREA. TIMING TOOL BRINGS THE LINE INTO KLAF AROUND 16Z.
SOUTHWARD EXTENT OF THE LINE WILL DETERMINE WHETHER OR NOT IT WILL
IMPACT OTHER SITES AND THINK KIND IS CLOSE ENOUGH TO BUMP UP THE
VCTS BUT NOT CONFIDENT ENOUGH TO ADD TEMPO THERE AT THIS TIME. STILL
EXPECTING ANOTHER LINE LATER ASSOCIATED WITH THE COLD FRONT.
PREVIOUS DISCUSSION FOLLOWS...
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL SPREAD OVER TAF SITES
THIS AFTERNOON AS A COLD FRONT ENTERS THE AREA. ACTIVITY WILL
START ENTERING KLAF BETWEEN FRI 18-21Z...MOVING SOUTHEAST THROUGH
THE REMAINING SITES. CONVECTION WILL INTENSIFY DURING THE SAT
00Z-06Z TIME FRAME. CONDITIONS WILL GENERALLY BE AT VFR CATEGORY
EXCEPT DURING ANY STRONG STORMS THAT COULD RESULT IN BRIEF MVFR
CONDITIONS. IT ISN/T UNTIL AFTER SAT 06Z THAT CONDITIONS WILL
QUICKLY PLUMMET TO MVFR OR WORSE AS CEILINGS LOWER FURTHER.
WINDS WILL BE SOUTHWESTERLY INTO THE EVENING HOURS...AND A LITTLE
BREEZY WITH SUSTAINED SPEEDS OF 10 TO 12 KTS. WINDS WILL VEER TO
THE NORTHWEST TONIGHT AFTER FRONTAL PASSAGE...SUSTAINED AT
8 TO 10 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...TDUD/CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
955 AM EDT FRI SEP 5 2014
.UPDATE...
NEAR TERM FOR THE REST OF TODAY HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 955 AM EDT FRI SEP 5 2014
.UPDATE...CURRENT FORECAST IS ON TRACK AND ONLY MINOR CHANGES MADE
WITH THIS UPDATE...MAINLY TO RAISE POPS SLIGHTLY OVER FAR NORTHERN
SECTIONS AS SHOWERS AND THUNDERSTORMS WERE ALREADY OVER NORTHEAST
ILLINOIS WHICH MAY BRUSH FAR NORTHERN AREAS IN A FEW HOURS.
PORTION OF PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MOST CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST
AREA ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN
GREAT LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND
A SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE
TO THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 342 AM EDT FRI SEP 5 2014
DRY CONDITIONS CAN BE EXPECTED ON MONDAY WITH ZONAL FLOW ALOFT AND
WEAK HIGH PRESSURE STILL AT THE SURFACE. HOWEVER...THE PATTERN WILL
QUICKLY SHIFT BY TUESDAY AS A BROAD UPPER TROUGH ENTERS THE AREA.
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS CENTRAL
INDIANA AS EARLY AS TUESDAY MORNING...WITH INCREASING CHANCES
THROUGH THE COURSE OF THE EXTENDED PERIOD AS A COLD FRONT TRACKS
ACROSS THE AREA ON WEDNESDAY NIGHT/THURSDAY. PRECIP CHANCES WILL
TAPER OFF TOWARD THE END OF THE PERIOD...BUT WILL KEEP MENTION OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH THURSDAY NIGHT TO
ACCOUNT FOR PASSAGE OF UPPER LOW. TEMPS WILL CONTINUE TO DROP WELL
BELOW NORMAL THROUGH THE COURSE OF THE EXTENDED PERIOD WITH HIGH
TEMPS ONLY IN THE UPPER 60S/LOW 70S BY FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 05/1200Z TAF ISSUANCE/...
ISSUED AT 711 AM EDT FRI SEP 5 2014
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL SPREAD OVER TAF SITES
THIS AFTERNOON AS A COLD FRONT ENTERS THE AREA. ACTIVITY WILL
START ENTERING KLAF BETWEEN FRI 18-21Z...MOVING SOUTHEAST THROUGH
THE REMAINING SITES. CONVECTION WILL INTENSIFY DURING THE SAT
00Z-06Z TIME FRAME. CONDITIONS WILL GENERALLY BE AT VFR CATEGORY
EXCEPT DURING ANY STRONG STORMS THAT COULD RESULT IN BRIEF MVFR
CONDITIONS. IT ISN/T UNTIL AFTER SAT 06Z THAT CONDITIONS WILL
QUICKLY PLUMMET TO MVFR OR WORSE AS CEILINGS LOWER FURTHER.
WINDS WILL BE SOUTHWESTERLY INTO THE EVENING HOURS...AND A LITTLE
BREEZY WITH SUSTAINED SPEEDS OF 10 TO 12 KTS. WINDS WILL VEER TO
THE NORTHWEST TONIGHT AFTER FRONTAL PASSAGE...SUSTAINED AT
8 TO 10 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
733 AM EDT FRI SEP 5 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
JUST A FEW HIGH CLOUDS DRIFTING ACROSS CENTRAL INDIANA EARLY THIS
MORNING AS REGION RESIDES UNDER THE INFLUENCE OF THE RIDGING ALOFT
CENTERED OVER THE LOWER MISSISSIPPI VALLEY EAST THROUGH THE
SOUTHEAST STATES. 07Z TEMPS RANGED FROM THE UPPER 60S TO MID 70S.
CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST AREA
ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN GREAT
LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND A
SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE TO
THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 342 AM EDT FRI SEP 5 2014
DRY CONDITIONS CAN BE EXPECTED ON MONDAY WITH ZONAL FLOW ALOFT AND
WEAK HIGH PRESSURE STILL AT THE SURFACE. HOWEVER...THE PATTERN WILL
QUICKLY SHIFT BY TUESDAY AS A BROAD UPPER TROUGH ENTERS THE AREA.
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS CENTRAL
INDIANA AS EARLY AS TUESDAY MORNING...WITH INCREASING CHANCES
THROUGH THE COURSE OF THE EXTENDED PERIOD AS A COLD FRONT TRACKS
ACROSS THE AREA ON WEDNESDAY NIGHT/THURSDAY. PRECIP CHANCES WILL
TAPER OFF TOWARD THE END OF THE PERIOD...BUT WILL KEEP MENTION OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH THURSDAY NIGHT TO
ACCOUNT FOR PASSAGE OF UPPER LOW. TEMPS WILL CONTINUE TO DROP WELL
BELOW NORMAL THROUGH THE COURSE OF THE EXTENDED PERIOD WITH HIGH TEMPS
ONLY IN THE UPPER 60S/LOW 70S BY FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 05/1200Z TAF ISSUANCE/...
ISSUED AT 711 AM EDT FRI SEP 5 2014
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL SPREAD OVER TAF SITES
THIS AFTERNOON AS A COLD FRONT ENTERS THE AREA. ACTIVITY WILL
START ENTERING KLAF BETWEEN FRI 18-21Z...MOVING SOUTHEAST THROUGH
THE REMAINING SITES. CONVECTION WILL INTENSIFY DURING THE SAT
00Z-06Z TIME FRAME. CONDITIONS WILL GENERALLY BE AT VFR CATEGORY
EXCEPT DURING ANY STRONG STORMS THAT COULD RESULT IN BRIEF MVFR
CONDITIONS. IT ISN/T UNTIL AFTER SAT 06Z THAT CONDITIONS WILL
QUICKLY PLUMMET TO MVFR OR WORSE AS CEILINGS LOWER FURTHER.
WINDS WILL BE SOUTHWESTERLY INTO THE EVENING HOURS...AND A LITTLE
BREEZY WITH SUSTAINED SPEEDS OF 10 TO 12 KTS. WINDS WILL VEER TO
THE NORTHWEST TONIGHT AFTER FRONTAL PASSAGE...SUSTAINED AT
8 TO 10 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
417 AM EDT FRI SEP 5 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
JUST A FEW HIGH CLOUDS DRIFTING ACROSS CENTRAL INDIANA EARLY THIS
MORNING AS REGION RESIDES UNDER THE INFLUENCE OF THE RIDGING ALOFT
CENTERED OVER THE LOWER MISSISSIPPI VALLEY EAST THROUGH THE
SOUTHEAST STATES. 07Z TEMPS RANGED FROM THE UPPER 60S TO MID 70S.
CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST AREA
ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN GREAT
LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND A
SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE TO
THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 342 AM EDT FRI SEP 5 2014
DRY CONDITIONS CAN BE EXPECTED ON MONDAY WITH ZONAL FLOW ALOFT AND
WEAK HIGH PRESSURE STILL AT THE SURFACE. HOWEVER...THE PATTERN WILL
QUICKLY SHIFT BY TUESDAY AS A BROAD UPPER TROUGH ENTERS THE AREA.
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS CENTRAL
INDIANA AS EARLY AS TUESDAY MORNING...WITH INCREASING CHANCES
THROUGH THE COURSE OF THE EXTENDED PERIOD AS A COLD FRONT TRACKS
ACROSS THE AREA ON WEDNESDAY NIGHT/THURSDAY. PRECIP CHANCES WILL
TAPER OFF TOWARD THE END OF THE PERIOD...BUT WILL KEEP MENTION OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH THURSDAY NIGHT TO
ACCOUNT FOR PASSAGE OF UPPER LOW. TEMPS WILL CONTINUE TO DROP WELL
BELOW NORMAL THROUGH THE COURSE OF THE EXTENDED PERIOD WITH HIGH TEMPS
ONLY IN THE UPPER 60S/LOW 70S BY FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 05/0900Z TAF UPDATE/...
ISSUED AT 415 AM EDT FRI SEP 5 2014
UPDATE...
NO CHANGES TO KIND. DELAYED ONSET OF FOG FORMATION AT KBMG BY AN HOUR.
PREVIOUS DISCUSSION...
A COLD FRONT FROM WISCONSIN TO KANSAS IS EXPECTED TO BE NEAR LAF BY
00Z SATURDAY AND IND AND HUF AROUND 06Z SATURDAY. THUNDERSTORMS
SHOULD BE INCREASING IN COVERAGE LATE THIS AFTERNOON AND ESPECIALLY
AFTER 00Z TONIGHT. WILL GO WITH VCTS AT LAF AFTER 18Z AND THE OTHER
SITES AFTER 21Z WITH THUNDERSTORMS IN THE PREVAILING GROUP AFTER 21Z
AT LAF AND 00Z AT THE OTHER SITES. ANY CEILING SHOULD BE
VFR...EXCEPT PERHAPS IN THUNDERSTORMS THIS AFTERNOON...UNTIL THE
OVERNIGHT.
COULD SEE SOME MVFR OR WORSE FOG OVERNIGHT...ESPECIALLY AT BMG.
WOULD NOT RULE OUT A THUNDERSTORM AT LAF OVERNIGHT OR ELSEWHERE THIS
MORNING...BUT CHANCES THAT ONE WOULD HIT ANY PARTICULAR TAF SITE ARE
LOW WITH CONFIDENCE AVERAGE.
WINDS WILL PICK UP TO 10 KNOTS OR SO FROM SOUTHWEST AFTER 15Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...MK/TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
343 AM EDT FRI SEP 5 2014
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
JUST A FEW HIGH CLOUDS DRIFTING ACROSS CENTRAL INDIANA EARLY THIS
MORNING AS REGION RESIDES UNDER THE INFLUENCE OF THE RIDGING ALOFT
CENTERED OVER THE LOWER MISSISSIPPI VALLEY EAST THROUGH THE
SOUTHEAST STATES. 07Z TEMPS RANGED FROM THE UPPER 60S TO MID 70S.
CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST AREA
ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN GREAT
LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND A
SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE TO
THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 342 AM EDT FRI SEP 5 2014
DRY CONDITIONS CAN BE EXPECTED ON MONDAY WITH ZONAL FLOW ALOFT AND
WEAK HIGH PRESSURE STILL AT THE SURFACE. HOWEVER...THE PATTERN WILL
QUICKLY SHIFT BY TUESDAY AS A BROAD UPPER TROUGH ENTERS THE AREA.
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS CENTRAL
INDIANA AS EARLY AS TUESDAY MORNING...WITH INCREASING CHANCES
THROUGH THE COURSE OF THE EXTENDED PERIOD AS A COLD FRONT TRACKS
ACROSS THE AREA ON WEDNESDAY NIGHT/THURSDAY. PRECIP CHANCES WILL
TAPER OFF TOWARD THE END OF THE PERIOD...BUT WILL KEEP MENTION OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH THURSDAY NIGHT TO
ACCOUNT FOR PASSAGE OF UPPER LOW. TEMPS WILL CONTINUE TO DROP WELL
BELOW NORMAL THROUGH THE COURSE OF THE EXTENDED PERIOD WITH HIGH TEMPS
ONLY IN THE UPPER 60S/LOW 70S BY FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 05/0600Z TAF ISSUANCE/...
ISSUED AT 1240 AM EDT FRI SEP 5 2014
A COLD FRONT FROM WISCONSIN TO KANSAS IS EXPECTED TO BE NEAR LAF BY
00Z SATURDAY AND IND AND HUF AROUND 06Z SATURDAY. THUNDERSTORMS
SHOULD BE INCREASING IN COVERAGE LATE THIS AFTERNOON AND ESPECIALLY
AFTER 00Z TONIGHT. WILL GO WITH VCTS AT LAF AFTER 18Z AND THE OTHER
SITES AFTER 21Z WITH THUNDERSTORMS IN THE PREVAILING GROUP AFTER 21Z
AT LAF AND 00Z AT THE OTHER SITES. ANY CEILING SHOULD BE
VFR...EXCEPT PERHAPS IN THUNDERSTORMS THIS AFTERNOON...UNTIL THE
OVERNIGHT.
COULD SEE SOME MVFR OR WORSE FOG OVERNIGHT...ESPECIALLY AT BMG.
WOULD NOT RULE OUT A THUNDERSTORM AT LAF OVERNIGHT OR ELSEWHERE THIS
MORNING...BUT CHANCES THAT ONE WOULD HIT ANY PARTICULAR TAF SITE ARE
LOW WITH CONFIDENCE AVERAGE.
WINDS WILL PICK UP TO 10 KNOTS OR SO FROM SOUTHWEST AFTER 15Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
324 AM EDT FRI SEP 5 2014
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
JUST A FEW HIGH CLOUDS DRIFTING ACROSS CENTRAL INDIANA EARLY THIS
MORNING AS REGION RESIDES UNDER THE INFLUENCE OF THE RIDGING ALOFT
CENTERED OVER THE LOWER MISSISSIPPI VALLEY EAST THROUGH THE
SOUTHEAST STATES. 07Z TEMPS RANGED FROM THE UPPER 60S TO MID 70S.
CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST AREA
ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN GREAT
LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND A
SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE TO
THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 242 PM EDT THU SEP 4 2014
TEMPERATURES SHOULD BE ABOUT 5 DEGREES BELOW NORMAL THROUGH THE LONG
TERM WITH A TROUGH GENERALLY CONTROLLING THE WEATHER OVER THE
EASTERN HALF OF THE COUNTRY. THE LONG TERM WILL START OUT DRY BUT
CHANCES FOR THUNDERSTORMS WILL RETURN BY MONDAY NIGHT/TUESDAY AND
STAY THROUGH THE REST OF THE PERIOD AS WAVES MOVE THROUGH THE MAIN
TROUGH AND A FRONTAL SYSTEM SLOWLY MAKES ITS WAY THROUGH THE AREA.
MADE ONLY MINOR QUALITY CONTROL/COLLABORATION CHANGES TO THE
INITIALIZATION.
&&
.AVIATION /DISCUSSION FOR THE 05/0600Z TAF ISSUANCE/...
ISSUED AT 1240 AM EDT FRI SEP 5 2014
A COLD FRONT FROM WISCONSIN TO KANSAS IS EXPECTED TO BE NEAR LAF BY
00Z SATURDAY AND IND AND HUF AROUND 06Z SATURDAY. THUNDERSTORMS
SHOULD BE INCREASING IN COVERAGE LATE THIS AFTERNOON AND ESPECIALLY
AFTER 00Z TONIGHT. WILL GO WITH VCTS AT LAF AFTER 18Z AND THE OTHER
SITES AFTER 21Z WITH THUNDERSTORMS IN THE PREVAILING GROUP AFTER 21Z
AT LAF AND 00Z AT THE OTHER SITES. ANY CEILING SHOULD BE
VFR...EXCEPT PERHAPS IN THUNDERSTORMS THIS AFTERNOON...UNTIL THE
OVERNIGHT.
COULD SEE SOME MVFR OR WORSE FOG OVERNIGHT...ESPECIALLY AT BMG.
WOULD NOT RULE OUT A THUNDERSTORM AT LAF OVERNIGHT OR ELSEWHERE THIS
MORNING...BUT CHANCES THAT ONE WOULD HIT ANY PARTICULAR TAF SITE ARE
LOW WITH CONFIDENCE AVERAGE.
WINDS WILL PICK UP TO 10 KNOTS OR SO FROM SOUTHWEST AFTER 15Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....MK
AVIATION...MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1224 PM CDT FRI SEP 5 2014
.SYNOPSIS...
ISSUED AT 304 AM CDT FRI SEP 5 2014
COLD FRONT OVER SOUTHEAST IOWA WILL MOVE SOUTHEAST OF IA TODAY AS
A WAVE LIFTS NORTHEAST ALONG THE FRONT THIS AFTERNOON AND EVENING.
HIGH PRESSURE WILL BUILD INTO THE STATE TODAY AND TONIGHT. THE
NEXT FRONTAL SYSTEM WILL APPROACH THE STATE MONDAY...MOVING SLOWLY
THROUGH IOWA THROUGH MID WEEK.
&&
.SHORT TERM /TODAY/...
ISSUED AT 304 AM CDT FRI SEP 5 2014
SLOW MOVING COLD FRONT WILL FINALLY CLEAR THE FAR SOUTHEAST
CORNER OF THE FORECAST AREA B/T 12-14Z THIS MORNING. THE
ASSOCIATED BROKEN LINE OF WEAK CONVECTION LOOKS TO LINGER
THROUGH SUNRISE BEFORE THE LLJ WEAKENS AND RESULTS IN STORMS
DIMINISHING IN INTENSITY AND COVERAGE BY 12Z OR EVEN SOONER. HAVE
LIKELY POPS GOING THROUGH THIS TIME...GENERALLY B/T THE HWY 20 AND
HWY 30 CORRIDORS...THEN CHANCE POPS ACROSS THE SOUTHERN HALF OF
THE FORECAST AREA THE REMAINDER OF THE MORNING.
NEXT SHORTWAVE LOOKS TO ENTER THE SOUTHERN PORTION OF THE STATE
LATER THIS MORNING INTO THE AFTERNOON HOURS AND BRINGS ANOTHER
ROUND OF SHOWERS/TSTMS ACROSS THE FORECAST AREA INTO THIS
EVENING. BROAD LARGE SCALE FORCING WITH THIS SHORTWAVE AND ENOUGH
THETA-E ADVECTION TO WARRANT CHANCE POPS ACROSS THE SOUTHERN TWO-
THIRDS OF THE FORECAST LATE THIS MORNING AND INTO THE AFTERNOON.
THE 05.05Z HRRR SEEMS A BIT TOO FAST WITH RAIN BUT AGREE WITH THE
COVERAGE ACROSS CENTRAL IOWA. THE 05.00Z HOPWRF SIMILAR WITH THE
COVERAGE BUT THINK IT HAS A BETTER HANDLE ON THE TIMING OF THE
PRECIP AND LEANED TOWARD THE HOPWRF FOR POP TRENDS TODAY.
CONSIDERED A NON-DIURNAL TEMPERATURE TREND TODAY BUT SHOULD WARM UP
ENOUGH LATER THIS MORNING INTO THE AFTERNOON ACROSS MUCH OF THE
FORECAST AREA...SO HAD LOW CONFIDENCE IT WOULD BE WIDESPREAD ENOUGH
TO MENTION.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 304 AM CDT FRI SEP 5 2014
CLEARING WILL SPREAD SOUTHEAST A HIGH PRESSURE BUILDS IN TO THE
STATE. THE WEEKEND LOOKS TO BE A QUITE WEEKEND WITH NO RAINFALL
EXPECTED AND TEMPERATURES BELOW NORMAL.
THE WEATHER PATTERN WILL BECOME MORE ACTIVE NEXT WEEK. DECENT
THETA-E ADVECTION BEGINS BY MONDAY MORNING AND WILL CONTINUE
PERIODICALLY THROUGH MID WEEK. RAINFALL AMOUNTS WILL HINGE ON HOW
MUCH OF THE MOISTURE FROM "NORBERT" IS PULLED INTO THE SYSTEM. IT
APPEARS THAT THE BULK OF THE MOISTURE WILL BE SWEPT EAST PASSING
OVER SOUTHERN IA OR FARTHER SOUTH. A STRONG UPPER TROUGH WILL
CARVE OUT FOR THE FOLLOWING WEEKEND. MODEL CONTINUITY IS DECENT
WITH THE MACRO SYSTEMS...DIFFERING IN DETAIL...BUT THE MESSAGE OF
SHARPLY COLDER IS PLAYED BY ALL.
&&
.AVIATION...05/18Z
ISSUED AT 1224 PM CDT FRI SEP 5 2014
THICK LAYERED CLOUDS WILL REMAIN ACROSS THE AREA THIS AFTERNOON
INTO EVENING...THEN CLEAR FROM NORTHWEST TO SOUTHEAST. THIS WILL
RESULT IN MVFR CIGS AT TIMES THIS AFTERNOON...ALONG WITH PERIODS
OF SHRA/TSRA MAINLY AT DSM/OTM WHICH HAVE BEEN COVERED WITH TEMPO
GROUPS. AFTER THIS EVENING AS CLEARING OCCURS CONDITIONS WILL
IMPROVE RAPIDLY...WITH LIGHT WINDS AND SKC EXPECTED FROM LATER
TONIGHT THROUGH TOMORROW.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MS SEP 14
SHORT TERM...PODRAZIK
LONG TERM...MS SEP 14
AVIATION...LEE
AREA FORECAST DISCUSSION
NWS DES MOINES IA
638 AM CDT FRI SEP 5 2014
...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 304 AM CDT FRI SEP 5 2014
COLD FRONT OVER SOUTHEAST IOWA WILL MOVE SOUTHEAST OF IA TODAY AS
A WAVE LIFTS NORTHEAST ALONG THE FRONT THIS AFTERNOON AND EVENING.
HIGH PRESSURE WILL BUILD INTO THE STATE TODAY AND TONIGHT. THE
NEXT FRONTAL SYSTEM WILL APPROACH THE STATE MONDAY...MOVING SLOWLY
THROUGH IOWA THROUGH MID WEEK.
&&
.SHORT TERM /TODAY/...
ISSUED AT 304 AM CDT FRI SEP 5 2014
SLOW MOVING COLD FRONT WILL FINALLY CLEAR THE FAR SOUTHEAST
CORNER OF THE FORECAST AREA B/T 12-14Z THIS MORNING. THE
ASSOCIATED BROKEN LINE OF WEAK CONVECTION LOOKS TO LINGER
THROUGH SUNRISE BEFORE THE LLJ WEAKENS AND RESULTS IN STORMS
DIMINISHING IN INTENSITY AND COVERAGE BY 12Z OR EVEN SOONER. HAVE
LIKELY POPS GOING THROUGH THIS TIME...GENERALLY B/T THE HWY 20 AND
HWY 30 CORRIDORS...THEN CHANCE POPS ACROSS THE SOUTHERN HALF OF
THE FORECAST AREA THE REMAINDER OF THE MORNING.
NEXT SHORTWAVE LOOKS TO ENTER THE SOUTHERN PORTION OF THE STATE
LATER THIS MORNING INTO THE AFTERNOON HOURS AND BRINGS ANOTHER
ROUND OF SHOWERS/TSTMS ACROSS THE FORECAST AREA INTO THIS
EVENING. BROAD LARGE SCALE FORCING WITH THIS SHORTWAVE AND ENOUGH
THETA-E ADVECTION TO WARRANT CHANCE POPS ACROSS THE SOUTHERN TWO-
THIRDS OF THE FORECAST LATE THIS MORNING AND INTO THE AFTERNOON.
THE 05.05Z HRRR SEEMS A BIT TOO FAST WITH RAIN BUT AGREE WITH THE
COVERAGE ACROSS CENTRAL IOWA. THE 05.00Z HOPWRF SIMILAR WITH THE
COVERAGE BUT THINK IT HAS A BETTER HANDLE ON THE TIMING OF THE
PRECIP AND LEANED TOWARD THE HOPWRF FOR POP TRENDS TODAY.
CONSIDERED A NON-DIURNAL TEMPERATURE TREND TODAY BUT SHOULD WARM UP
ENOUGH LATER THIS MORNING INTO THE AFTERNOON ACROSS MUCH OF THE
FORECAST AREA...SO HAD LOW CONFIDENCE IT WOULD BE WIDESPREAD ENOUGH
TO MENTION.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 304 AM CDT FRI SEP 5 2014
CLEARING WILL SPREAD SOUTHEAST A HIGH PRESSURE BUILDS IN TO THE
STATE. THE WEEKEND LOOKS TO BE A QUITE WEEKEND WITH NO RAINFALL
EXPECTED AND TEMPERATURES BELOW NORMAL.
THE WEATHER PATTERN WILL BECOME MORE ACTIVE NEXT WEEK. DECENT
THETA-E ADVECTION BEGINS BY MONDAY MORNING AND WILL CONTINUE
PERIODICALLY THROUGH MID WEEK. RAINFALL AMOUNTS WILL HINGE ON HOW
MUCH OF THE MOISTURE FROM "NORBERT" IS PULLED INTO THE SYSTEM. IT
APPEARS THAT THE BULK OF THE MOISTURE WILL BE SWEPT EAST PASSING
OVER SOUTHERN IA OR FARTHER SOUTH. A STRONG UPPER TROUGH WILL
CARVE OUT FOR THE FOLLOWING WEEKEND. MODEL CONTINUITY IS DECENT
WITH THE MACRO SYSTEMS...DIFFERING IN DETAIL...BUT THE MESSAGE OF
SHARPLY COLDER IS PLAYED BY ALL.
&&
.AVIATION...05/12Z
ISSUED AT 638 AM CDT FRI SEP 5 2014
MVFR CIGS LOOK TO AFFECT OTM THROUGH THE MID MORNING AND HAVE
HANDLED VIA TEMPO. SCATTERED SHOWER ACTIVITY WILL CONTINUE TO
DIMINISH THIS MORNING AND HAVE VCSH OR VCTS MENTIONED THIS MORNING
WITH LOW CONFIDENCE RAIN LASTING LONGER THAN AN HOUR AT TIMES.
OTHERWISE...CAA SETS IN THROUGH THE AFTERNOON WITH NEXT WAVE
BRINGING ADDITIONAL RAIN CHANCES OVER SOUTHERN IOWA. MAY ONLY
AFFECT OTM ATTM.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MS SEP 14
SHORT TERM...PODRAZIK
LONG TERM...MS SEP 14
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1156 PM CDT THU SEP 4 2014
.UPDATE...
ISSUED AT 947 PM CDT THU SEP 4 2014
AREA RADAR MOSAIC AT 9 PM WAS SHOWING ELEVATED SHOWERS DEVELOPING
OVER FAR W CENTRAL IA INTO NE NEB...WHERE THE RAP MODEL WAS
SHOWING A WEAKENING IN THE STRONG CAP/ELEVATED MIXED LAYER WITH 14
C PLUS TEMPERATURES AT 700 MB THAT AT 00Z STRETCHED FROM NEW
MEXICO NORTHEAST THROUGH THE CENTRAL PLAINS INTO IA AND NW IL. THE
DEVELOPING CONVECTION WAS BEHIND THE SURFACE FRONT THAT EXTENDED
FROM SE MN THROUGH CHARLES CITY INTO W CENTRAL IA JUST SE OF THE
DES MOINES METRO AREA...WHERE KDMX WAS PAINTING THIS BOUNDARY WITH
A FINE LINE ECHO.
THE STRONG CAP OVERHEAD IS PROJECTED BY THE RAP TO WEAKEN AS A WEAK
SHORTWAVE APPROACHING THE MO RIVER PUSHES INTO EASTERN IA AFTER
09Z. THIS WOULD BE ALONG AND AHEAD OF THE SURFACE FRONT LIKELY TO
BE MOVING INTO EASTERN IA AT THIS TIME. 00Z 850 MB ANALYSIS
SHOWED A VERY MOIST AXIS FROM THE LOWER MS VALLEY NORTH THROUGH
CENTRAL IA AND SE MN...WITH DEWPOINTS ABOVE 16 C AHEAD OF THE COLD
FRONT. PW VALUES FROM 00Z WERE FROM 1.5 TO 1.75 IN THIS AXIS.
THE THETAE CONVERGENCE INTO ANY DEVELOPING CONVECTION...AS SHOWN
BY THE RAP...COULD LEAD TO LOCALLY HEAVY RAINFALL...ESPECIALLY IF
CONVECTION ORGANIZES AS SUGGESTED.
THIS CONVECTIVE EVOLUTION DOES NOT STRAY TOO FAR FROM THE CURRENT
FORECAST...BUT WILL BE MAKING SOME TWEAKS CLOSER TO THIS SOLUTION
IN AN UPDATE OUT SHORTLY. OUT AHEAD OF THE FRONT...WIDESPREAD
DEWPOINTS HOLDING IN THE LOWER AND MID 70S DUE TO CONTINUED
WARM ADVECTION IN THE ON THE LOW LEVEL SOUTHERLY FLOW...WILL KEEP
MINS IN THE LOWER AND POSSIBLY MID 70S IN AREAS OF THE FAR EAST
AND SOUTHEAST NOT AS LIKELY TO SEE RAINFALL OVERNIGHT.
&&
.SYNOPSIS...
ISSUED AT 327 PM CDT THU SEP 4 2014
THE CLUSTER OF THUNDERSTORMS THAT BROUGHT RAIN TO AREA OVERNIGHT
THROUGH EARLY AFTERNOON HAS SHIFTED EAST AND DISSIPATED. AFTERNOON
HEAT INDICES IN AREAS NOT IMPACTED BY THESE STORMS...GENERALLY
SOUTHWEST OF A LINE FROM DBQ TO MLI TO PRINCETON IL HAVE PUSHED
INTO THE UPPER 90S TO LOWER 100S. A COLD FRONT STRETCHES FROM A
SURFACE LOW IN NORTHWEST MN TO FSD AND INTO EASTERN NE. THUNDERSTORMS
IN MN AND NORTHERN WI ARE ASSOCIATED WITH THE WARM FRONT ALSO
EMANATING FROM THE SURFACE LOW.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 327 PM CDT THU SEP 4 2014
MAIN CONCERN IS TIMING THE COLD FRONTAL PASSAGE OVERNIGHT AND THE
ASSOCIATED PRECIP. MODELS AGREE IN BRINGING THE FRONT INTO THE
CWA AFTER 06Z THEN EXITING THE CWA FRIDAY AFTERNOON. MODELS ALSO
AGREE AMONGST EACH OTHER AND WITH CURRENT OBSERVATIONS IN THAT
PRECIP IS AND WILL BE POST FRONTAL. THUS TIMING OF THE FRONT IS
CRITICAL AND DRIVES THE PRECIP CHANCES...AS WELL AS MIN TEMPS
OVERNIGHT WHICH WILL VARY FROM POST FRONTAL IN THE NORTHWEST TO
WARM SECTOR IN THE SOUTHEAST.
AS THE FRONT SLOWS DOWN TOMORROW WITH THE SURFACE LOW WELL TO OUR
NORTH AND SOME WEAK UPPER LEVEL SUPPORT FROM THE PROGRESSIVE
TROUGH...CLOUDS AND PRECIP CHANCES WILL LINGER. I EXPECT THIS TO
BE MORE FALL-LIKE IN NATURE WITH SHOWERS AND EMBEDDED THUNDERSTORMS...
THUS NO SEVERE THREAT. WOLF
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 327 PM CDT THU SEP 4 2014
SPLENDID EARLY FALL WEATHER ARRIVING BY WEEKEND WITH MORE CHANCES OF
SHOWERS AND STORMS EARLY NEXT WEEK.
LONG TERM FORECAST CONFIDENCE...FAIR (AVERAGE) OVERALL. POOR OR BELOW
AVERAGE ON TIMING AND AMOUNTS OF RAIN EVENTS EARLY NEXT WEEK AND WITH
TIMING AND STRENGTH OF COLD TO POSSIBLY MUCH COLDER AIR ARRIVING LATE
NEXT WEEK.
OVERVIEW...INITIALIZATION AND VERIFICATION IS FAIR TO POOR WITH ONGOING
QPF FALLING TODAY AND ALSO WITH ENERGY OFF PACIFIC IMPACTING SW MONSOON
THAT MAY IMPACT AREA EARLY TO MIDDLE OF NEXT WEEK. THE AMOUNT OF LATENT
HEAT RELEASED ALSO MAY WELL IMPACT STRENGTH OF UPPER TROUGH DIVING INTO
PLAINS LATE NEXT WEEK. RUN TO RUN VARIANCES AND INTER-SOLUTION TRENDS
SUPPORTS A 70/30 BLEND OF HI- RES ECMWF WITH GEM WITH ONLY MINOR INPUTS
OF GFS AS HIGH AMOUNTS OF SW MONSOON MOISTURE APPEARS QUESTIONABLE TO
PHASE WITH FRONTAL SYSTEM WED/THU.
FRIDAY NIGHT...KEPT EVENING POPS OF MAINLY LIGHT SHOWERS AS SURFACE
FRONT SLIDES EAST WITH SUBSIDENCE SUPPORTING CLEARING ALL AREAS BETWEEN
MIDNIGHT AND SUNRISE SATURDAY AS COOL AIR MOVES IN. MINS UPPER 40S FAR
NE TO NEAR 60F FAR SE STILL REASONABLE.
SATURDAY AND SUNDAY...BEAUTIFUL EARLY FALL WEATHER AS CANADIAN HIGH
PRESSURE MOVES IN WITH LOWER 70S FOR HIGHS SATURDAY AND MOSTLY MIDDLE
70S ON SUNDAY UNDER A SUNNY SKY. DEWPOINTS IN THE UPPER 40S TO LOWER
50S ALSO SUGGEST PRISTINE EARLY FALL AIR. MINS SUNDAY AM SHOULD BE
IN THE UPPER 40S IN FAVORED LOW LYING LOCATIONS OF ROCK/WAPSI RIVER
VALLEYS AND LOWER 50S ELSEWHERE WITH MONDAY AM LOWS MAINLY IN THE
LOWER 50S. NW WINDS OF 10-20 MPH SATURDAY...BECOMING LIGHT SATURDAY
NIGHT THROUGH SUNDAY NIGHT.
MONDAY...SLIGHTLY WARMER WITH HIGHS AGAIN IN THE UPPER 70S TO AROUND
80 DEGREES SUGGESTED WITH INCREASING CLOUDS LATE AND CHANCE OF LIGHT
SHOWERS FROM THE WEST. SOUTH WINDS OF 5 TO 15 MPH BY AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY NIGHT...UNSETTLED WITH CHANCES OF
SHOWERS AND STORMS WITH POOR CONFIDENCE OF PHASING OF MONSOON MOISTURE
AHEAD OF DEVELOPING UPPER LEVEL TROUGH. IF SKIES HAVE LESS CLOUDS
THEN HIGH TEMPERATURES MAY NEED RAISING BY UP TO 5 DEGREES FOR LATER
SHIFTS. FAVORABLE REGIME FOR MODERATE TO LOCALLY LOWER END HEAVY RAIN
AMOUNTS OVER A QUARTER INCH TO AGAIN LOCALLY OVER AN INCH PLUS ARE
SUGGESTED BY FRONTAL PASSAGE WEDNESDAY NIGHT FOR NO WATER ISSUES
SUGGESTED NOR ANY SEVERE RISK. MINS IN THE UPPER 50S TO LOWER 60S.
THURSDAY...COOLER TO POTENTIALLY MUCH COOLER AS STRONG EARLY FALL FRONT
TO PASS. FORECAST HIGHS ARE POSSIBLY 5 PLUS DEGREES TOO HIGH FOR LATER
SHIFTS TO REASSESS...OR POSSIBLY LOW/MID 60S. MINS FRIDAY MORNING AS
LOW AS THE LOW/MID 40S SUGGESTED...OR 3-5 DEGREES COLDER THAN THIS FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1155 PM CDT THU SEP 4 2014
A COLD FRONT MOVING THROUGH CENTRAL IOWA WILL PUSH SOUTHEAST
THROUGH THE TERMINALS LATE TONIGHT AND EARLY FRIDAY MORNING. THIS
WILL PROVIDE A SHIFT IN SURFACE WINDS FROM SOUTHWEST TO
NORTHWEST...ALONG WITH AT LEAST SCATTERED SHOWERS AND
THUNDERSTORMS... WHICH HAS BEEN HANDLED WITH TEMPO WORDING. THERE
IS ALSO A GOOD POTENTIAL FOR LOW CLOUDS...RESULTING IN MVFR
CONDITIONS THROUGH MUCH OF THE MORNING HOURS. SCATTERED SHOWERS
ARE POSSIBLE DURING THE AFTERNOON...BUT BETTER CHANCES APPEAR TO
BE LATE AFTERNOON AND EVENING...WHERE PROB30 WORDING HAS BEEN
UTILIZED.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...SHEETS
SYNOPSIS...WOLF
SHORT TERM...WOLF
LONG TERM...NICHOLS
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1259 PM CDT FRI SEP 5 2014
...UPDATED FOR AVIATION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 100 AM CDT FRI SEP 5 2014
EVEN THOUGH WE HAVE NOT REACHED THE EQUINOX (23 SEPT 2014), WE ARE CERTAINLY
IN METEOROLOGICAL FALL AND TODAY WILL GIVE US THE FIRST DOSAGE OF FALL-
LIKE WEATHER WITH COOL TEMPERATURES, SHOWERS, CLOUDS, AND A RAW NNE/NE
WIND.
FOR THE REST OF THIS MORNING, HEAVILY BIASED THE SPATIOTEMPORAL ARRANGEMENT
OF POPS AND RESULTANT WEATHER GRIDS TO THE 4 KM NAM. THIS MODEL HAD
MORE OF A CLUE WITH INITIAL CONDITIONS THAN COMPARED TO THE OPERATIONAL
NAM AND THE WRF. RECENT HRRR GUIDANCE IS ALSO SOMEWHAT IN AGREEMENT
WITH THE 4 KM NAM AS WELL, ALBEIT, A BIT LIBERAL WITH THE EASTWARD
PROGRESSION. FOR THE BOTTOM LINE, SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE TO DEVELOP ALONG THE 800-700-HPA BAROCLINIC BOUNDARY WITH
UPSLOPE/300K ISENTROPIC LIFT. BUFKIT PLUME SPREADS STILL SUPPORT A GOOD/SOAKING
RAIN WITH PRECIPITATION AMOUNTS GENERALLY IN THE 0.50-1.00" RANGE ALONG
THE SW TO NE ORIENTED BAROCLINIC BOUNDARY. THE AREA THAT WILL SEE THE
LEAST IS ACROSS SOUTH-CENTRAL KANSAS. EVENTUALLY, SUBSIDENCE AND ISENTROPIC
DOWNGLIDE WILL DEVELOP IN THE WAKE OF A PASSING SYNOPTIC WAVE. THE END
RESULT WILL BE A REDUCTION IN COVERAGE AND INTENSITY OF THE SHOWERS
LATER ON TODAY. LASTLY, SEVERE WEATHER IS NOT EXPECTED TODAY. JUST AN
OCCASIONAL LIGHTNING BOLT, BUT NOTHING ORGANIZED/SEVERE.
THE OTHER STORY FOR TODAY IS MAXIMUM TEMPERATURES. SIDED WITH THE COOLER
SOLUTION WITH MORE LOW 60SF ACROSS RAIN-COOLED AREAS AND KEPT THE WARMEST
ACROSS SOUTH-CENTRAL KANSAS, WHERE THIS AREA WILL BE IN THE WARM SECTOR
LONGER (WENT WITH AROUND 80F FOR MEDICINE LODGE).
IF SHOWERS AND ISOLATED THUNDERSTORMS DO CONTINUE THROUGH THE OVERNIGHT
HOURS, IT WOULD BE MAINLY NEAR THE OKLAHOMA BORDER AS THE BAROCLINIC
BOUNDARY SINKS SOUTH. FOR MINIMUMS, TEMPERATURES WILL FEEL THE COLDEST
IN QUITE A WHILE (LIKE SINCE LAST MAY). AS CLOUDS ERODE AND UNDER THE
INFLUENCE OF HIGH PRESSURE AND SINGLE DIGIT 850-HPA TEMPERATURES, THINK
THAT SOME AREAS (LIKE THE INTERSTATE 70 CORRIDOR) COULD SEE SOME UPPER
40SF. THE REST OF THE AREA WILL BE IN THE LOW TO MID 50SF. GOOD NIGHT
TO FINALLY OPEN UP THAT WINDOW AND BRING SOME CRISP BUT REFRESHING
FALL AIR IN AND GIVE THE AIR CONDITIONING UNIT A REST.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 348 AM CDT FRI SEP 5 2014
A TRANSITION TO A MORE FALL PATTERN, AT LEAST TEMPORARILY, IS IN
PROGRESS ON THIS SIDE OF THE HEMISPHERE WITH VIGOROUS UPPER LEVEL
TROUGHS RIPPLING THROUGH THE FLOW AND OCCASIONAL INCURSIONS OF
CANADIAN AIR INTO THE CENTRAL AND EASTERN UNITED STATES. CHALLENGES
FOR THE EXTENDED PERIOD INCLUDE THE EFFECTS OF INJECTION OF TROPICAL
MOISTURE FROM HURRICANE NORBERT ON PRECIPITATION COVERAGE EARLY NEXT
WEEK AND ANTICIPATING THE AMPLITUDE OF THE AMPLIFYING TROUGH THAT
DIGS INTO THE NORTHERN PLAINS AND SOUTHERN CANADA BY THE MIDDLE OF
NEXT WEEK.
LARGE SCALE FORCING FROM THE TROPICS REMAINS POORLY ORGANIZED.
OUTGOING LONG WAVE RADIATION SUGGESTS THAT THERE IS A WEAK COHERENT
SIGNAL THAT PROJECTS ONTO A MADDEN JULIAN OSCILLATION NEAR 140E THAT
MAY APPROACH THE DATELINE AROUND 15-16 SEPTEMBER, BUT MOST OF THE
GLOBAL MODELS SUGGEST THAT TROPICAL THUNDERSTORMS WILL REDEVELOP
BACK IN THE WESTERN INDIAN OCEAN BY MID SEPTEMBER. TEMPERATURES HAVE
BEEN ANOMALOUSLY COOL IN CENTRAL ASIA RECENTLY, AND EASTERLY FLOW
AGAINST THE MOUNTAINS IN EASTERN ASIA APPEAR TO BE CONTRIBUTING TO
THE POSITIVE MOUNTAIN TORQUE ON THE ATMOSPHERE. RELATIVE
ATMOSPHERIC ANGULAR MOMENTUM HAS BEEN TRENDING UPWARD SLOWLY, AND
THE FLOW FOR THE NEXT WEEK OR SO IS BEST REPRESENTED BY PHASE 4 OF
THE GLOBAL WIND OSCILLATION. THIS CORRELATES WITH ANTICYCLONIC
FLOW IN THE WESTERN UNITED STATES. AS SUCH, THE IDEA OF
MAINTAINING RIDGING FROM THE SOUTHWESTERN UNITED STATES TO WESTERN
CANADA NEXT WEEK IS VERY REASONABLE. THE ECMWF CONTINUES TO BE
MORE AMPLIFIED WITH A TROUGH THAT DIGS INTO THE NORTHERN PLAINS
NEXT FRIDAY THAN IS THE GFS. SOME OF THE GFS ENSEMBLE MEMBERS ARE
EVEN DEEPER AND SLOWER WITH THE CLOSED CYCLONE THAT DEEPENS NEAR
THE CANADIAN BORDER NEXT THURSDAY THAN THE ECMWF, AND THE GEM
ENSEMBLE MEMBERS EXHIBIT CONSIDERABLE SPREAD. THE ECMWF MAY BE
SLIGHTLY OVERDONE WITH THE STRENGTH OF THE TROUGH DIGGING INTO THE
NORTHERN PLAINS LATE NEXT WEEK, BUT THE GENERAL PATTERN LOOKS
GOOD. THERE WILL BE A SIGNIFICANT INVASION OF CANADIAN AIR INTO
THE CENTRAL AND NORTHERN PART OF THE COUNTRY NEXT WEDNESDAY, AND
THERE PROBABLY WILL BE WIDESPREAD FROST AND SOME FREEZING
TEMPERATURES ACROSS THE NORTHERN PLAINS NEXT FRIDAY AND SATURDAY
MORNINGS.
AFTER THE COLD AIR DRAINS SOUTHWARD NEXT WEEK, IT APPEARS LIKELY
THAT A MORE ZONAL FLOW REGIME WITH BROAD RIDGING IN THE WESTERN PART
OF THE COUNTRY WILL BECOME ESTABLISHED. TEMPERATURES WILL RETURN TO
NEAR OR ABOVE SEASONAL AVERAGES BY 16-17 SEPTEMBER, AND MOST OF THE
REST OF THE MONTH SHOULD BE FAIRLY WARM.
IN THE MORE IMMEDIATE FUTURE, SATURDAY SHOULD BE COOL WITH LIGHT
WINDS AND CLEARING SKIES AS HIGH PRESSURE BUILDS INTO THE CENTRAL
PLAINS. HIGHS IN THE LOWER HALF OF THE 70S CAN BE EXPECTED WITH H8
TEMPERATURES FROM 12 TO 15 DEGREES C. LOW LEVEL FLOW WILL RETURN TO
THE SOUTH SATURDAY NIGHT BUT WILL REMAIN LIGHT AND VARIABLE FOR MUCH
OF THE NIGHT IN CENTRAL KANSAS. TEMPERATURES WILL FALL TO NEAR 50
AGAIN IN NORTH CENTRAL KANSAS. LOWS WILL BE SOMEWHAT WARMER NEAR THE
COLORADO BORDER WHERE WARM AIR ADVECTION WILL BEGIN EARLIER IN THE
NIGHT.
PRESSURES WILL FALL IN THE NORTHERN ROCKIES AND PLAINS SATURDAY
NIGHT AND SUNDAY AS THE NEXT VIGOROUS UPPER LEVEL TROUGH APPROACHES
BRITISH COLUMBIA, AND A PLUME OF WARM AIR WILL SPREAD EAST FROM THE
ROCKIES. MID LEVEL FRONTOGENESIS LIKELY WILL SUPPORT SOME MID LEVEL
CLOUDINESS SUNDAY, AND ISENTROPIC LIFTING OVER THE RETREATING COOL
AIR MASS AS A LOW LEVEL JET DEVELOPS SUNDAY NIGHT LIKELY WILL
SUPPORT EVOLUTION OF SCATTERED NOCTURNAL ELEVATED SHOWERS AND
THUNDERSTORMS. IT IS UNCERTAIN EXACTLY HOW FAR WEST THE SHOWERS WILL
DEVELOP, BUT THE THE MOST LIKELY AREA IS EAST OF HIGHWAY 283.
MONDAY WILL BE WARM AGAIN, AND HIGH LEVEL TROPICAL MOISTURE FROM
HURRICANE NORBERT WILL BEGIN TO SPREAD INTO THE HIGH PLAINS.
THUNDERSTORMS LIKELY WILL INITIATE ALONG A CONVERGENCE ZONE FROM
NORTHWEST KANSAS INTO EASTERN COLORADO AND SPREAD EAST DURING THE
EVENING. THE GFS CARRIES THE REMNANTS OF NORBERT INTO THE CENTRAL
PART OF THE COUNTRY TUESDAY, WHILE THE ECMWF IS A LITTLE SLOWER TO
EJECT THE CARCASS. BOTH MODELS CARRY A SUBSTANTIAL INJECTION OF HIGH
LEVEL TROPICAL MOISTURE ACROSS THE CENTRAL PART OF THE COUNTRY, AND
A WEAK FRONTAL BOUNDARY IS LIKELY TO EXIST IN WESTERN KANSAS. THE
SYNOPTIC DETAILS ARE UNCERTAIN, BUT ANY CONVERGENCE ZONE WILL BE
SUFFICIENT TO SUPPORT THUNDERSTORM DEVELOPMENT.
CANADIAN AIR WILL INVADE KANSAS WEDNESDAY, AND MUCH COOLER WEATHER
WILL PREVAIL THURSDAY AND FRIDAY. A REINFORCING SURGE OF COLD AIR
WILL ARRIVE ABOUT FRIDAY. UPSLOPE FLOW AND EXTENSIVE CLOUDINESS MAY
KEEP TEMPERATURES IN THE 50S FRIDAY. RAIN CHANCES WILL DEPEND ON THE
STRENGTH OF THE UPPER LEVEL TROUGH THAT DIGS INTO THE NORTHERN PART
OF THE COUNTRY. IF THE ECMWF IS CORRECT, TEMPERATURES COULD DROP
INTO THE UPPER 30S AS FAR SOUTH AS NORTHERN KANSAS WHEN THE CLOUD
COVER FINALLY CLEARS OUT. SUCH DETAILS ARE HIGHLY UNCERTAIN THAT
FAR IN THE FUTURE, HOWEVER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1253 PM CDT FRI SEP 5 2014
AREAS OF MVFR/IFR CIGS WILL CONTINUE INTO TONIGHT WITH CIGS
IMPROVING TO VFR AFTER 12-15Z. AREAS OF LIGHT RAIN SHOWERS WILL
GRADUALLY DECREASE BY 00Z AS THE CURRENT TROPICAL WAVE MOVES EAST.
LIGHT NORTH TO NORTHEAST WINDS OF 10-15KT WILL CONTINUE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 63 50 73 53 / 90 30 10 10
GCK 61 49 73 53 / 100 30 10 10
EHA 62 51 73 54 / 90 40 10 10
LBL 66 53 74 54 / 90 40 20 10
HYS 61 49 73 50 / 80 30 10 10
P28 80 58 74 56 / 50 50 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...RUTHI
AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
352 AM CDT FRI SEP 5 2014
...UPDATED LONG TERM SECTION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 100 AM CDT FRI SEP 5 2014
EVEN THOUGH WE HAVE NOT REACHED THE EQUINOX (23 SEPT 2014), WE ARE CERTAINLY
IN METEOROLOGICAL FALL AND TODAY WILL GIVE US THE FIRST DOSAGE OF FALL-
LIKE WEATHER WITH COOL TEMPERATURES, SHOWERS, CLOUDS, AND A RAW NNE/NE
WIND.
FOR THE REST OF THIS MORNING, HEAVILY BIASED THE SPATIOTEMPORAL ARRANGEMENT
OF POPS AND RESULTANT WEATHER GRIDS TO THE 4 KM NAM. THIS MODEL HAD
MORE OF A CLUE WITH INITIAL CONDITIONS THAN COMPARED TO THE OPERATIONAL
NAM AND THE WRF. RECENT HRRR GUIDANCE IS ALSO SOMEWHAT IN AGREEMENT
WITH THE 4 KM NAM AS WELL, ALBEIT, A BIT LIBERAL WITH THE EASTWARD
PROGRESSION. FOR THE BOTTOM LINE, SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE TO DEVELOP ALONG THE 800-700-HPA BAROCLINIC BOUNDARY WITH
UPSLOPE/300K ISENTROPIC LIFT. BUFKIT PLUME SPREADS STILL SUPPORT A GOOD/SOAKING
RAIN WITH PRECIPITATION AMOUNTS GENERALLY IN THE 0.50-1.00" RANGE ALONG
THE SW TO NE ORIENTED BAROCLINIC BOUNDARY. THE AREA THAT WILL SEE THE
LEAST IS ACROSS SOUTH-CENTRAL KANSAS. EVENTUALLY, SUBSIDENCE AND ISENTROPIC
DOWNGLIDE WILL DEVELOP IN THE WAKE OF A PASSING SYNOPTIC WAVE. THE END
RESULT WILL BE A REDUCTION IN COVERAGE AND INTENSITY OF THE SHOWERS
LATER ON TODAY. LASTLY, SEVERE WEATHER IS NOT EXPECTED TODAY. JUST AN
OCCASIONAL LIGHTNING BOLT, BUT NOTHING ORGANIZED/SEVERE.
THE OTHER STORY FOR TODAY IS MAXIMUM TEMPERATURES. SIDED WITH THE COOLER
SOLUTION WITH MORE LOW 60SF ACROSS RAIN-COOLED AREAS AND KEPT THE WARMEST
ACROSS SOUTH-CENTRAL KANSAS, WHERE THIS AREA WILL BE IN THE WARM SECTOR
LONGER (WENT WITH AROUND 80F FOR MEDICINE LODGE).
IF SHOWERS AND ISOLATED THUNDERSTORMS DO CONTINUE THROUGH THE OVERNIGHT
HOURS, IT WOULD BE MAINLY NEAR THE OKLAHOMA BORDER AS THE BAROCLINIC
BOUNDARY SINKS SOUTH. FOR MINIMUMS, TEMPERATURES WILL FEEL THE COLDEST
IN QUITE A WHILE (LIKE SINCE LAST MAY). AS CLOUDS ERODE AND UNDER THE
INFLUENCE OF HIGH PRESSURE AND SINGLE DIGIT 850-HPA TEMPERATURES, THINK
THAT SOME AREAS (LIKE THE INTERSTATE 70 CORRIDOR) COULD SEE SOME UPPER
40SF. THE REST OF THE AREA WILL BE IN THE LOW TO MID 50SF. GOOD NIGHT
TO FINALLY OPEN UP THAT WINDOW AND BRING SOME CRISP BUT REFRESHING
FALL AIR IN AND GIVE THE AIR CONDITIONING UNIT A REST.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 348 AM CDT FRI SEP 5 2014
A TRANSITION TO A MORE FALL PATTERN, AT LEAST TEMPORARILY, IS IN
PROGRESS ON THIS SIDE OF THE HEMISPHERE WITH VIGOROUS UPPER LEVEL
TROUGHS RIPPLING THROUGH THE FLOW AND OCCASIONAL INCURSIONS OF
CANADIAN AIR INTO THE CENTRAL AND EASTERN UNITED STATES. CHALLENGES
FOR THE EXTENDED PERIOD INCLUDE THE EFFECTS OF INJECTION OF TROPICAL
MOISTURE FROM HURRICANE NORBERT ON PRECIPITATION COVERAGE EARLY NEXT
WEEK AND ANTICIPATING THE AMPLITUDE OF THE AMPLIFYING TROUGH THAT
DIGS INTO THE NORTHERN PLAINS AND SOUTHERN CANADA BY THE MIDDLE OF
NEXT WEEK.
LARGE SCALE FORCING FROM THE TROPICS REMAINS POORLY ORGANIZED.
OUTGOING LONG WAVE RADIATION SUGGESTS THAT THERE IS A WEAK COHERENT
SIGNAL THAT PROJECTS ONTO A MADDEN JULIAN OSCILLATION NEAR 140E THAT
MAY APPROACH THE DATELINE AROUND 15-16 SEPTEMBER, BUT MOST OF THE
GLOBAL MODELS SUGGEST THAT TROPICAL THUNDERSTORMS WILL REDEVELOP
BACK IN THE WESTERN INDIAN OCEAN BY MID SEPTEMBER. TEMPERATURES HAVE
BEEN ANOMALOUSLY COOL IN CENTRAL ASIA RECENTLY, AND EASTERLY FLOW
AGAINST THE MOUNTAINS IN EASTERN ASIA APPEAR TO BE CONTRIBUTING TO
THE POSTITIVE MOUNTAIN TORQUE ON THE ATMOSPHERE. RELATIVE
ATMOSPHERIC ANGULAR MOMENTUM HAS BEEN TRENDING UPWARD SLOWLY, AND
THE FLOW FOR THE NEXT WEEK OR SO IS BEST REPRESENTED BY PHASE 4 OF
THE GLOBAL WIND OSCILLATION. THIS CORRELATES WITH ANTICYCLONIC FLOW
IN THE WESTERN UNITED STATES. AS SUCH, THE IDEA OF MAINTAINING
RIDGING FROM THE SOUTHWESTERN UNITED STATES TO WESTERN CANADA NEXT
WEEK IS VERY REASONABLE. THE ECMWF CONTINUES TO BE MORE AMPLIFIED
WITH A TROUGH THAT DIGS INTO THE NORTHERN PLAINS NEXT FRIDAY THAN IS
THE GFS. SOME OF THE GFS ENSEMBLE MEMBERS ARE EVEN DEEPER AND SLOWER
WITH THE CLOSED CYCLONE THAT DEEPENS NEAR THE CANADIAN BORDER NEXT
THURSDAY THAN THE ECMWF, AND THE GEM ENSEMBLE MEMBERS EXHIBIT
CONSIDERABLE SPREAD. THE ECMWF MAY BE SLIGHTLY OVERDONE WITH THE
STRENGTH OF THE TROUGH DIGGING INTO THE NORTHERN PLAINS LATE NEXT
WEEK, BUT THE GENERAL PATTERN LOOKS GOOD. THERE WILL BE A
SIGNIFICANT INVASION OF CANADIAN AIR INTO THE CENTRAL AND NORTHERN
PART OF THE COUNTRY NEXT WEDNESDAY, AND THERE PROBABLY WILL BE
WIDESPREAD FROST AND SOME FREEZING TEMPERATURES ACROSS THE NORTHERN
PLAINS NEXT FRIDAY AND SATURDAY MORNINGS.
AFTER THE COLD AIR DRAINS SOUTHWARD NEXT WEEK, IT APPEARS LIKELY
THAT A MORE ZONAL FLOW REGIME WITH BROAD RIDGING IN THE WESTERN PART
OF THE COUNTRY WILL BECOME ESTABLISHED. TEMPERATURES WILL RETURN TO
NEAR OR ABOVE SEASONAL AVERAGES BY 16-17 SEPTEMBER, AND MOST OF THE
REST OF THE MONTH SHOULD BE FAIRLY WARM.
IN THE MORE IMMEDIATE FUTURE, SATURDAY SHOULD BE COOL WITH LIGHT
WINDS AND CLEARING SKIES AS HIGH PRESSURE BUILDS INTO THE CENTRAL
PLAINS. HIGHS IN THE LOWER HALF OF THE 70S CAN BE EXPECTED WITH H8
TEMPERATURES FROM 12 TO 15 DEGREES C. LOW LEVEL FLOW WILL RETURN TO
THE SOUTH SATURDAY NIGHT BUT WILL REMAIN LIGHT AND VARIABLE FOR MUCH
OF THE NIGHT IN CENTRAL KANSAS. TEMPERATURES WILL FALL TO NEAR 50
AGAIN IN NORTH CENTRAL KANSAS. LOWS WILL BE SOMEWHAT WARMER NEAR THE
COLORADO BORDER WHERE WARM AIR ADVECTION WILL BEGIN EARLIER IN THE
NIGHT.
PRESSURES WILL FALL IN THE NORTHERN ROCKIES AND PLAINS SATURDAY
NIGHT AND SUNDAY AS THE NEXT VIGOROUS UPPER LEVEL TROUGH APPROACHES
BRITISH COLUMBIA, AND A PLUME OF WARM AIR WILL SPREAD EAST FROM THE
ROCKIES. MID LEVEL FRONTOGENESIS LIKELY WILL SUPPORT SOME MID LEVEL
CLOUDINESS SUNDAY, AND ISENTROPIC LIFTING OVER THE RETREATING COOL
AIR MASS AS A LOW LEVEL JET DEVELOPS SUNDAY NIGHT LIKELY WILL
SUPPORT EVOLUTION OF SCATTERED NOCTURNAL ELEVATED SHOWERS AND
THUNDERSTORMS. IT IS UNCERTAIN EXACTLY HOW FAR WEST THE SHOWERS WILL
DEVELOP, BUT THE THE MOST LIKELY AREA IS EAST OF HIGHWAY 283.
MONDAY WILL BE WARM AGAIN, AND HIGH LEVEL TROPICAL MOISTURE FROM
HURRICANE NORBERT WILL BEGIN TO SPREAD INTO THE HIGH PLAINS.
THUNDERSTORMS LIKELY WILL INITIATE ALONG A CONVERGENCE ZONE FROM
NORTHWEST KANSAS INTO EASTERN COLORADO AND SPREAD EAST DURING THE
EVENING. THE GFS CARRIES THE REMNANTS OF NORBERT INTO THE CENTRAL
PART OF THE COUNTRY TUESDAY, WHILE THE ECMWF IS A LITTLE SLOWER TO
EJECT THE CARCASS. BOTH MODELS CARRY A SUBSTANTIAL INJECTION OF HIGH
LEVEL TROPICAL MOISTURE ACROSS THE CENTRAL PART OF THE COUNTRY, AND
A WEAK FRONTAL BOUNDARY IS LIKELY TO EXIST IN WESTERN KANSAS. THE
SYNOPTIC DETAILS ARE UNCERTAIN, BUT ANY CONVERGENCE ZONE WILL BE
SUFFICIENT TO SUPPORT THUNDERSTORM DEVELOPMENT.
CANADIAN AIR WILL INVADE KANSAS WEDNESDAY, AND MUCH COOLER WEATHER
WILL PREVAIL THURSDAY AND FRIDAY. A REINFORCING SURGE OF COLD AIR
WILL ARRIVE ABOUT FRIDAY. UPSLOPE FLOW AND EXTENSIVE CLOUDINESS MAY
KEEP TEMPERATURES IN THE 50S FRIDAY. RAIN CHANCES WILL DEPEND ON THE
STRENGTH OF THE UPPER LEVEL TROUGH THAT DIGS INTO THE NORTHERN PART
OF THE COUNTRY. IF THE ECMWF IS CORRECT, TEMPERATURES COULD DROP
INTO THE UPPER 30S AS FAR SOUTH AS NORTHERN KANSAS WHEN THE CLOUD
COVER FINALLY CLEARS OUT. SUCH DETAILS ARE HIGHLY UNCERTAIN THAT
FAR IN THE FUTURE, HOWEVER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1200 AM CDT FRI SEP 5 2014
NOT A GOOD TAF PD FOR VFR GA PILOTS. CIGS WILL REDUCE TO MVFR THIS
MORNING IN ASSOCIATION WITH WIDESPREAD -SHRA AND ASSOCIATED LOW
CEILINGS. CIGS MAY IMPROVE BACK TO VFR BY THIS EVENING AS SUBSIDENCE
INCREASES. WINDS WILL BE NNE/NE 8-18 KT THROUGH MUCH OF TODAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 66 50 73 53 / 80 30 10 10
GCK 63 49 73 53 / 90 30 10 10
EHA 65 51 73 54 / 80 40 10 10
LBL 70 53 74 54 / 70 40 20 10
HYS 63 49 73 50 / 80 30 10 10
P28 81 58 74 56 / 50 40 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...RUTHI
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
100 AM CDT FRI SEP 5 2014
...UPDATE TO SHORT TERM...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 100 AM CDT FRI SEP 5 2014
EVEN THOUGH WE HAVE NOT REACHED THE EQUINOX (23 SEPT 2014), WE ARE CERTAINLY
IN METEOROLOGICAL FALL AND TODAY WILL GIVE US THE FIRST DOSAGE OF FALL-
LIKE WEATHER WITH COOL TEMPERATURES, SHOWERS, CLOUDS, AND A RAW NNE/NE
WIND.
FOR THE REST OF THIS MORNING, HEAVILY BIASED THE SPATIOTEMPORAL ARRANGEMENT
OF POPS AND RESULTANT WEATHER GRIDS TO THE 4 KM NAM. THIS MODEL HAD
MORE OF A CLUE WITH INITIAL CONDITIONS THAN COMPARED TO THE OPERATIONAL
NAM AND THE WRF. RECENT HRRR GUIDANCE IS ALSO SOMEWHAT IN AGREEMENT
WITH THE 4 KM NAM AS WELL, ALBEIT, A BIT LIBERAL WITH THE EASTWARD
PROGRESSION. FOR THE BOTTOM LINE, SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE TO DEVELOP ALONG THE 800-700-HPA BAROCLINIC BOUNDARY WITH
UPSLOPE/300K ISENTROPIC LIFT. BUFKIT PLUME SPREADS STILL SUPPORT A GOOD/SOAKING
RAIN WITH PRECIPITATION AMOUNTS GENERALLY IN THE 0.50-1.00" RANGE ALONG
THE SW TO NE ORIENTED BAROCLINIC BOUNDARY. THE AREA THAT WILL SEE THE
LEAST IS ACROSS SOUTH-CENTRAL KANSAS. EVENTUALLY, SUBSIDENCE AND ISENTROPIC
DOWNGLIDE WILL DEVELOP IN THE WAKE OF A PASSING SYNOPTIC WAVE. THE END
RESULT WILL BE A REDUCTION IN COVERAGE AND INTENSITY OF THE SHOWERS
LATER ON TODAY. LASTLY, SEVERE WEATHER IS NOT EXPECTED TODAY. JUST AN
OCCASIONAL LIGHTNING BOLT, BUT NOTHING ORGANIZED/SEVERE.
THE OTHER STORY FOR TODAY IS MAXIMUM TEMPERATURES. SIDED WITH THE COOLER
SOLUTION WITH MORE LOW 60SF ACROSS RAIN-COOLED AREAS AND KEPT THE WARMEST
ACROSS SOUTH-CENTRAL KANSAS, WHERE THIS AREA WILL BE IN THE WARM SECTOR
LONGER (WENT WITH AROUND 80F FOR MEDICINE LODGE).
IF SHOWERS AND ISOLATED THUNDERSTORMS DO CONTINUE THROUGH THE OVERNIGHT
HOURS, IT WOULD BE MAINLY NEAR THE OKLAHOMA BORDER AS THE BAROCLINIC
BOUNDARY SINKS SOUTH. FOR MINIMUMS, TEMPERATURES WILL FEEL THE COLDEST
IN QUITE A WHILE (LIKE SINCE LAST MAY). AS CLOUDS ERODE AND UNDER THE
INFLUENCE OF HIGH PRESSURE AND SINGLE DIGIT 850-HPA TEMPERATURES, THINK
THAT SOME AREAS (LIKE THE INTERSTATE 70 CORRIDOR) COULD SEE SOME UPPER
40SF. THE REST OF THE AREA WILL BE IN THE LOW TO MID 50SF. GOOD NIGHT
TO FINALLY OPEN UP THAT WINDOW AND BRING SOME CRISP BUT REFRESHING
FALL AIR IN AND GIVE THE AIR CONDITIONING UNIT A REST.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 321 PM CDT THU SEP 4 2014
SUNDAY AND MONDAY WILL BE MOSTLY DRY AS SURFACE HIGH PRESSURE WILL
BE LOCATED OVER THE CENTRAL PLAINS, WITH ANY PRECIPITATION WELL
TO THE SOUTH. A WEAK LEE TROUGH WILL BEGIN TO DEVELOP LATE SUNDAY
IN RESPONSE TO THE APPROACH OF A MINOR SHORTWAVE TROUGH; BUT
CURRENT THINKING IS THAT CONVECTIVE INITIATION IS NOT LIKELY DUE
TO MARGINAL LOW LEVEL MOISTURE AND LOW SURFACE BASED CAPE.
TEMPERATURES WILL BE IN A WARMING TREND DUE TO WESTERLY MID LEVEL
FLOW, LEE TROUGHING AND SOUTHERLY WINDS. BY MONDAY, THE NEXT
SHORTWAVE TROUGH WILL APPROACH, WITH INCREASING LOW LEVEL
MOISTURE. THUNDERSTORMS MAY DEVELOP IN CENTRAL AND SOUTH CENTRAL
KANSAS; AND THESE COULD BE SEVERE GIVEN MODERATE SURFACE BASED
CAPE AND VEERING WIND PROFILE. IF THE MODELS DISPLAY SOME RUN TO
RUN CONTINUITY WITH SEVERE WEATHER PARAMETERS, THEN WE WILL
MENTION POSSIBLE SEVERE IN THE HAZARDOUS WEATHER OUTLOOK IN LATER
SHIFTS. BY TUESDAY AND WEDNESDAY, UPPER LEVEL TROUGHING WILL
GRADUALLY PROGRESS FROM WESTERN CANADA INTO THE NORTHERN ROCKIES.
WITH CONTINUED LEE TROUGHING AND AVAILABLE LOW LEVEL MOISTURE,
THUNDERSTORMS ARE STILL POSSIBLE, ESPECIALLY GIVEN AN ENHANCEMENT
IN MID LEVEL MOISTURE FROM THE TROPICS AND A SURFACE FRONT
CONTRIBUTING TO LOW LEVEL CONVERGENCE. TEMPERATURES WILL DEPEND ON
THE TIMING AND COVERAGE OF PRECIPITATION, WITH HIGHS PROBABLY
REACHING AT LEAST INTO THE 80S AND POSSIBLY NEAR 90F THROUGH
TUESDAY. EVENTUALLY, AS TROUGHING CONTINUES TO AMPLIFY OVER THE
NORTHERN ROCKIES AND NORTHERN PLAINS, A STRONGER COLD FRONT WILL
ARRIVE, WITH HIGHS FALLING BACK INTO THE 60S OR 70S AS EARLY AS
FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1200 AM CDT FRI SEP 5 2014
NOT A GOOD TAF PD FOR VFR GA PILOTS. CIGS WILL REDUCE TO MVFR THIS
MORNING IN ASSOCIATION WITH WIDESPREAD -SHRA AND ASSOCIATED LOW
CEILINGS. CIGS MAY IMPROVE BACK TO VFR BY THIS EVENING AS SUBSIDENCE
INCREASES. WINDS WILL BE NNE/NE 8-18 KT THROUGH MUCH OF TODAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 50 72 53 78 / 30 10 10 10
GCK 49 72 53 78 / 30 10 10 10
EHA 51 71 54 82 / 40 20 10 10
LBL 53 71 54 80 / 40 20 10 10
HYS 49 73 53 77 / 30 0 10 10
P28 58 72 56 79 / 40 30 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...FINCH
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1046 PM MDT THU SEP 4 2014
.UPDATE...
ISSUED AT 850 PM MDT THU SEP 4 2014
AT 0240Z SHOWERS/THUNDERSTORMS HAVE INCREASED IN COVERAGE ALONG
AND JUST EAST OF THE CO/KS BORDER AS A WEATHER DISTURBANCE MOVES
IN FROM THE SOUTHWEST. 00Z NAM/RUC SUGGEST THAT THIS AREA OF
PRECIPITATION CONTINUES TO MOVE NORTHEAST THROUGH MIDNIGHT. IT
APPEARS PER 700-500RH THAT ANOTHER DISTURBANCE CURRENTLY OVER
SOUTHEAST COLORADO LIFTS NORTH/NORTHEAST INTO THE AREA AFTER
MIDNIGHT BRINGING HIGHER CHANCES OF RAIN AND A FEW THUNDERSTORMS
TO THE NORTHWEST 1/2-1/3 OF THE AREA. THE HRRR HAS THE HIGHER POPS
TO THE SOUTHEAST OF THIS LINE. SO...CONFIDENCE IS A BIT SHAKY AS
TO HOW THINGS DEVELOP AFTER MIDNIGHT. NO MAJOR ADJUSTMENTS MADE
THIS EVENING. DID INCREASE CLOUDINESS QUITE A BIT. OVERNIGHT LOWS
IN THE 50S STILL LOOKS GOOD AS DO THE NORTHEAST WINDS OF 10 TO 15
MPH.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 158 PM MDT THU SEP 4 2014
WV LOOP AND RAP ANALYSIS SHOWS EXPANSIVE UPPER RIDGE JUST TO OUR
SOUTHEAST WITH PLUME OF MID LEVEL MOISTURE MOVING NORTHEASTWARD
ACROSS THE SOUTHWEST CONUS IN TO THE CENTRAL ROCKIES. CIRRUS WAS
OVERSPREADING THE CENTRAL HIGH PLAINS. AHEAD OF AN EASTWARD MOVING
POSITIVELY TILTED SHORTWAVE TROUGH OVER THE NORTHERN PLAINS. A COLD
FRONT FORCED BY THE AFOREMENTIONED TROUGH HAS MADE IT THROUGH THE
FORECAST AREA AND TEMPERATURES WERE NOTICEABLY COOLER THAN 24 HOURS
PRIOR. MID TO UPPER 70S WERE COMMON IN THE NORTHWEST HALF OF THE
FORECAST AREA WHICH SAW THE EARLIEST FRONTAL PASSAGE. WINDS
IMMEDIATELY BEHIND THE FRONT GUSTED FROM THE NORTH AT 30-35 MPH BUT
HAVE SUBSIDED SOME THIS AFTERNOON. STILL...DIURNAL HEATING AND
MIXING IS CONTRIBUTING TO GUSTS APPROACHING 30 MPH. WINDS WILL
CONTINUE TO DECREASE THROUGH THE AFTERNOON...ESPECIALLY WHEN MIXING
LESSENS THIS EVENING.
CHALLENGES FOR THE SHORT TERM INCLUDE PRECIPITATION CHANCES THIS
EVENING THROUGH TOMORROW AND THE POSSIBILITY OF MARGINALLY SEVERE
HAIL WITH A FEW OF THE THUNDERSTORMS THIS EVENING. LOCALLY HEAVY
RAINFALL WILL BE POSSIBLE GIVEN PWAT VALUES APPROACHING 2 STANDARD
DEVIATIONS ABOVE CLIMO FOR EARLY SEPTEMBER. EVENT QPF TOTALS WILL BE
AROUND ONE INCH FOR THE FAR SOUTH PORTION OF THE FORECAST AREA
TAPERING TO A TENTH OF AN INCH OR LESS IN THE FAR NORTHWEST PORTION
OF THE AREA. STILL SOME UNCERTAINTY ON QPF AMOUNTS AND EXACT
PLACEMENT OF HEAVIER TOTALS ALTHOUGH SHORT RANGE GUIDANCE HAS COME
INTO BETTER AGREEMENT WITH TIMING.
SHOWERS AND THUNDERSTORMS SHOULD DEVELOP ACROSS THE SOUTHERN PORTION
OF THE AREA NEAR AND JUST NORTH OF THE FRONT LATER THIS EVENING AND
THEN CONTINUE TO DEVELOP NORTHWARD AS ISENTROPIC LIFT INCREASES ON
THE COOL SIDE OF THIS BOUNDARY. THE STRONGEST CONVECTION SHOULD
OCCUR THROUGH THE EVENING AND EARLY TONIGHT BEFORE INSTABILITY
WANES. ISOLATED MARGINALLY SEVERE HAIL SEEMS POSSIBLE GIVEN 30-40
KNOT DEEP LAYER SHEAR AND AROUND 1000 J/KG MUCAPE. THIS THREAT
SHOULD BE CONFINED TO THE SOUTHERN PORTION OF THE AREA. LATER IN THE
NIGHT SHOWERS AND THUNDERSTORMS SHOULD BECOME FAIRLY WIDESPREAD AS
ISENTROPIC LIFT MAXIMIZES OVER THE AREA...PARTICULARLY IN THE
SOUTHEASTERN PORTION WHERE HIGHER QPF AMOUNTS ARE. MODELS HAVE
TRENDED SLOWER SO ENDING TIME OF THE PRECIPITATION EVENT IS A LITTLE
UNCERTAIN BUT BY MID/LATE MORNING THE HEAVIEST PRECIPITATION WILL
HAVE SHIFTED EAST OF THE AREA. SOME SHOWERS WILL LINGER IN THE
SOUTHEAST THROUGH THE AFTERNOON BEFORE THE UPPER LEVEL TROUGH AXIS
MOVES THROUGH.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 158 PM MDT THU SEP 4 2014
FRIDAY NIGHT THERE MAYBE SOME LINGERING RAINFALL OVER THE FAR
EAST/SOUTHEAST PART OF THE AREA AHEAD OF THE DEPARTING 500MB SHORT
WAVE TROUGH. THE RAINFALL SHOULD BE EAST OF THE AREA BY MID TO LATE
EVENING. DUE TO THE LOWEST 50MB OR SO OF THE SOUNDINGS REMAINING
SATURATED THOUGHT ABOUT MENTIONING FOG IN THE FORECAST LATE FRIDAY
NIGHT. HOWEVER LOOKS LIKE THE CLOUD COVER WILL REMAIN OVER THE
AREA. IF SKIES CLEAR OVERNIGHT FOG WILL BE MUCH MORE LIKELY TO
DEVELOP. A SURFACE HIGH MOVES THROUGH THE AREA SO WINDS WILL BECOME
LIGHT AND VARIABLE. WITH A COOL AIR MASS IN PLACE LOWS WILL BE WELL
BELOW NORMAL.
SATURDAY AND SATURDAY NIGHT VERY WEAK RIPPLES IN THE UPPER LEVEL
FLOW MOVE OVER THE AREA. SOUNDINGS SHOW A CAPPED UNSATURATED
ENVIRONMENT SO THESE TWO PERIODS WILL BE DRY. DURING THE DAY THE
SURFACE HIGH MOVES EAST WHICH WILL ALLOW WARMER AIR FROM THE SOUTH
TO MOVE INTO THE AREA. SATURDAY NIGHT WILL BE A FEW DEGREES WARMER
THAN FRIDAY NIGHT.
SUNDAY THROUGH THURSDAY NUMEROUS WEAK UPPER LEVEL DISTURBANCES WILL
MOVE ACROSS THE AREA. LATEST RUN OF MODELS DISAGREES WITH THE
PROGRESSION AND LOCATION OF THE STRONGER UPPER LEVEL SHORT WAVE
TROUGH THAT WILL MOVE THROUGH MONDAY THROUGH TUESDAY...THUS LOWERING
CONFIDENCE OF WHEN/WHERE RAINFALL WILL DEVELOP. TUESDAY THROUGH
WEDNESDAY A STRONGER MORE WELL DEFINED UPPER LEVEL SHORT WAVE TROUGH
WILL MOVE THROUGH THE AREA...SO WILL HAVE HIGHER RAINFALL CHANCES AS
A RESULT. A STRONG COLD FRONT MOVES THROUGH WEDNESDAY EVENING BUT
MOISTURE AND UPPER LEVEL FORCING DO NOT LOOK VERY FAVORABLE FOR
STORM DEVELOPMENT AS THE FRONT MOVES THROUGH.
TEMPERATURES FOR THE PERIOD WILL GRADUALLY WARM THROUGH TUESDAY AS
THE COOLER AIR MASS GRADUALLY MOVES EAST. MID WEEK A STRONG COLD
FRONT MOVES INTO THE AREA WEDNESDAY NIGHT WITH THE COOLER AIR
CONTINUING TO MOVE INTO THE AREA THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1045 PM MDT THU SEP 4 2014
FOR KGLD AND KMCK...VFR CONDITIONS EXPECTED THROUGH THROUGH 12Z-
14Z BEFORE MVFR AND POSSIBLY IFR CONDITIONS IN RAIN/MIST/LOW CIGS
FROM ABOUT 14Z THROUGH 02Z MOVE IN. AFTER 02Z VFR CONDITIONS
EXPECTED TO RETURN. THIS IS IN RESPONSE TO A WEATHER DISTURBANCE
AND LARGE AREA OF MOISTURE MOVING THROUGH THE AREA FROM THE
SOUTHWEST. WINDS THROUGH MUCH OF THE PERIOD GENERALLY FROM THE
NORTHEAST AT 8-12KTS. AFTER 02Z LGT/VRB WINDS EXPECTED.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...BRB
LONG TERM...JTL
AVIATION...99
AREA FORECAST DISCUSSION
NWS GRAY ME
1017 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/...
1015PM UPDATE...
QUICK UPDATE WAS NEEDED TO RE-INSERT POP FOR SHOWERS NOW
OCCURRING ACROSS PARTS OF THE AREA. ADDITIONAL RAIN UPSTREAM IN
SOUTHWEST NEW ENGLAND IS MOVING GENERALLY TO THE EAST NORTHEAST
AND WILL PRIMARILY IMPACT SOUTHERN AND COASTAL AREAS OVERNIGHT.
THIS RAIN IS ASSOCIATED WITH A SHORTWAVE TROUGH ALOFT AND A WEAK
SURFACE LOW TRACKING NORTHEAST ALONG THE FRONT WHICH HAS ALREADY
MOVED THROUGH THE AREA. SOME OF THE MOISTURE WITH THIS IS BEING
FLUNG BACK INTO OUR AREA DESPITE THE COLD FRONTAL PASSAGE. DO NOT
EXPECT THUNDERSTORMS AND SHOULD ONLY SEE LIGHT RAIN AMOUNTS.
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 TWIN CITIES/CHANHASSEN MN
235 AM CDT FRI SEP 5 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 234 AM CDT FRI SEP 5 2014
SHORT TERM CONCERNS REMAIN EXTENT OF CLOUD COVER TODAY AND
TEMPERATURE TRENDS.
SOME ISOLATED THUNDER DEVELOPED OVER NORTHERN IOWA AND LIFTED
NORTHEAST AFFECTING A SMALL PART OF SOUTH CENTRAL MN AFTER MIDNIGHT.
THIS ACTIVITY SHOULD MOVE EAST AND GRADUALLY DISSIPATE THROUGH 12Z.
THEN SHEARED UPPER TROUGH MOVES EAST SOUTHEAST DURING THE DAY.
APPEARS THERE WILL BE A FAIR AMOUNT OF MID/UPPER LEVEL CLOUDS
ASSOCIATED WITH THIS FEATURE DURING THE DAY. SHOULD REMAIN DRY WITH
THE OVERALL DRY AIRMASS IN PLACE. THIS MAY LIMIT SUNSHINE HOWEVER
AND TEMPERATURE POTENTIAL SOMEWHAT...ALONG WITH THE CAA PATTERN.
WILL LIKELY SEE SOME STRATOCUMULUS WORK INTO NORTHERN PARTS OF THE
CWA AS WELL. PREVIOUS FORECAST TEMPERATURES LOOKED GOOD AND WERE
RETAINED.
CLEARING SHOULD OCCUR EARLY EVENING AS COOL HIGH PRESSURE BUILDS
EAST. TEMPERATURES EXPECTED TO COOL THROUGH THE MID 40S TO AROUND
50 WITH LIGHT WIND.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 234 AM CDT FRI SEP 5 2014
QUIET WEATHER WILL CONTINUE THROUGH EARLY NEXT WEEK WITH HIGH
PRESSURE DRIFTING ACROSS THE MID MISSOURI VALLEY SATURDAY...THE
MID MISSISSIPPI VALLEY SUNDAY AND THE LOWER GREAT LAKES/NEW
ENGLAND BY MONDAY MORNING. WEAK WAA WILL BRING SLOWLY MODERATING
TEMPS EACH DAY. CLEAR SKIES ARE EXPECTED.
MODELS ARE BEGINNING TO BACK OFF ON PRECIPITATION WITH THE SHORT
WAVE MONDAY AND MONDAY NIGHT. DESPITE THE DISTURBANCE PROPAGATING
OVERHEAD...MOISTURE APPEARS TO BE LACKING WITH TRAJECTORIES
ORIGINATING FROM THE HIGH PRESSURE SYSTEM AND MOST OF THE
PRECIPITATION LOOKS TO REMAIN SOUTH ACROSS MISSOURI AND IOWA.
CONTINUED TO REDUCE POPS SOME...WITH THE HIGHEST ACROSS SOUTHERN
MN.
THE PATTERN WILL BECOME MORE AMPLIFIED DURING THE MIDDLE OF NEXT
WEEK AS A TROUGH BEGINS TO DIG INTO THE NORTHERN ROCKIES AND
NORTHERN PLAINS. WITH THICKNESS PACKING SAGGING SOUTH AND MOISTURE
FROM HURRICANE NORBERT IN THE EASTERN PACIFIC BEING ADVECTED
NORTHEAST...IT WILL BE INTERESTING TO SEE HOW A SURFACE CYCLONE
DEVELOPS TO THE LEE OF THE ROCKIES. GFS AND ECMWF APPEAR TO BE IN
PRETTY GOOD AGREEMENT AT THIS RANGE WITH A LARGE AND INTENSIFYING
CYCLONE TRACKING FROM THE PANHANDLE REGION INTO THE GREAT LAKES BY
WEDNESDAY NIGHT/THURSDAY. THERE WILL BE MULTIPLE CHANCES FOR
PRECIPITATION DURING THIS PERIOD WITH THE FIRST BEING THE
PRECEDING SHORT WAVE...THE SECOND WITH THE COLD FRONT AND DIGGING
TROUGH...AND THE THIRD WITH THE DEFORMATION/INVERTED TROUGH
STRATIFORM RAIN ASSOCIATED WITH THE CYCLONE LATE WEEK.
FOLLOWING THAT SYSTEM...TEMPERATURES WILL DROP WELL BELOW AVERAGE.
HIGHS MAY ONLY BE IN THE 50S...AND LOWS COULD FALL INTO THE 30S
WITH AN EARLY SEASON FROST POSSIBLE JUST BEYOND THE CURRENT
FORECAST PERIOD AS SUB-540DM THICKNESSES AND STRONG SURFACE HIGH
PRESSURE MOVE IN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1052 PM CDT THU SEP 4 2014
THE PRIMARY CONCERN THIS TAF PERIOD IS THE POTENTIAL FOR MVFR CIGS
OVERNIGHT AND FRIDAY MORNING AS A LOBE OF LLVL MOISTURE SWINGS
DOWN ACROSS CENTRAL MN AND WEST CENTRAL WI. THE HIGHEST
PROBABILITY OF A BKN-OVC MVFR DECK IS AT KAXN AND KSTC...CLOSER TO
THE BETTER FETCH OF MOISTURE. HAVE INCLUDED SCT MVFR LEVEL CLOUDS
AT KMSP ON FRIDAY MORNING...AND BKN AT KRNH AND KEAU WHERE 0.5
KMAGL RAP CONDENSATIONAL PRESSURE DEFICITS DECREASE TO BETWEEN 10
AND 20 MB. THEN NORTHWEST WINDS AND DRIER AIR WORK INTO THE AREA
THROUGHOUT THE DAY AND CONTRIBUTE TO SCATTERING LOW CLOUDS BY THE
AFTERNOON WITH ONLY A SCT-BKN HIGH DECK REMAINING. SHOULD THEN SEE
CLEARING ON FRIDAY EVENING. NORTHWEST WINDS CIRCA 8-12KTS PREVAIL
THROUGH FRIDAY...WITH GUSTS INTO THE MID/UPPER TEENS DURING THE
DAYTIME. SPEEDS REDUCE TO AOB 5 KTS ON FRIDAY EVE AND BACK TO
WEST/SOUTHWEST IN DIRECTION.
KMSP...
HAVE KEPT A MENTION OF SCT 2500 FT CLOUDS ON FRIDAY MORNING...BUT
OTHERWISE VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD WITH SCT-
BKN HIGH CLOUDS UNTIL CLEARING COMMENCES AFTER 00Z SAT. NORTHWEST WINDS AT
AROUND 11KTS ON FRIDAY GUST TO AROUND 17 KTS DURING THE AFTERNOON...THEN
DECREASE BELOW 7 KTS FRIDAY EVE.
/OUTLOOK FOR KMSP/
SAT...VFR. WINDS W 5-10 KTS.
SUN...VFR. WINDS SW 5-10 KTS.
MON...MAINLY VFR. CHC MVFR IN SHRA/TSRA. WINDS S 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...DWE
LONG TERM...BORGHOFF
AVIATION...LS
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
832 PM CDT SAT SEP 6 2014
.UPDATE...
CONVECTION IS STILL HANGING AROUND A BIT BUT DOES APPEAR TO BE
SLOWLY DISSIPATING. THE 00Z SOUNDING SHOWED A PW OF 1.69 INCHES
WHICH IS CLOSE TO A HALF INCH LOWER THAN THE MAIN MODELS WERE
INDICATING AT THIS TIME. POPS WERE LOWERED FOR THE EVENING HOURS
TONIGHT. THE HRRR AND LOCAL WRF ARE SHOWING CONVECTION TO CONTINUE
DIMINISHING WHICH FALLS RIGHT IN LINE WITH THE CURRENT RADAR LOOP
AND LIGHTNING PLOT. ADJUSTED SOME SKY GRIDS BUT OTHER THAN THAT AND
THE POPS EVERYTHING APPEARS TO BE IN LINE WITH CURRENT CONDITIONS.
CAN EXPECT SOME PATCHY/DENSE FOG AGAIN TOMORROW MORNING IN SCATTERED
PLACES...PARTICULARLY UP IN THE NORTHERN ZONES. /10/
&&
.AVIATION...
LATE AFTERNOON CONVECTION IS ON THE DOWN SWING AND THE REMAINDER OF
THE NIGHT LOOKS TO BE QUIET. ONCE WE APPROACH 09-10Z...GUIDANCE IS
INDICATING SOME OF THE NORTHERN SITES COULD SEE SOME MVFR
CEILINGS/VIS DEVELOP AND LINGER UNTIL 15-16Z. ASIDE FROM THAT...VFR
CONDITIONS LOOK TO EXIST BY 16-17Z SUNDAY WITH THE BETTER CHANCES FOR
SCT ACTIVITY ACROSS THE S/SE. /CME/
&&
.PREV DISCUSSION... /ISSUED 423 PM CDT SAT SEP 6 2014/
DISCUSSION...
THIS AFTERNOON THROUGH SUNDAY NIGHT...
THE CONVECTIVE SCENARIO THIS AFTERNOON FEATURES A COLD FRONT
APPROACHING FROM THE NORTH WITH SHOWER AND THUNDERSTORM ACTIVITY
BUILDING ALONG AND JUST AHEAD OF IT OVER NORTHWEST PORTIONS OF THE
ARKLAMISS. THE CONVECTION IS SLOW TO PUSH FARTHER SOUTHEAST INTO THE
AREA AS NORTHERLY LOW LEVEL FLOW IS TENDING TO ANCHOR THE MOISTURE
CONVERGENCE AXIS...BUT EXPECT GRADUAL SE DEVELOPMENT AS WE GO INTO
THE EARLY EVENING. AS PREVIOUSLY MENTIONED THERE HAS BEEN A
CONVECTIVE MIN AREA OVER CENTRAL MS...BUT IT HAS BEEN A LITTLE LARGER
THAN ANTICIPATED --- WHILE ISOLATED CONVECTION HAS DEVELOPED OVER THE
GOLDEN TRIANGLE REGION...MOST OF THE REMAINDER OF THE ARKLAMISS HAS
BEEN VOID OF RAINFALL.
SO FOR THE REMAINDER OF THE AFTERNOON...HAVE CUT BACK ON POPS
SOME...BUT STILL BELIEVE INTERACTIONS ASSOC WITH CURRENT CONVECTIVE
AREAS COMBINED WITH CONTINUED DESTABILIZATION WILL PROMOTE SCATTERED
SHOWER/TSTM COVERAGE BY EARLY EVENING OVER CENTRAL PORTIONS OF THE
ARKLAMISS IN SPITE OF VERY WEAK TO NON-EXISTENT MOISTURE
CONVERGENCE. THIS THINKING IS REFLECTED BY THE BULK OF MOS GUIDANCE
WHICH IS IN PRETTY GOOD AGREEMENT WITH HIGHER POPS OVER CENTRAL
PORTIONS OF THE AREA. THE THINKING IS STILL THE SAME REGARDING
CONVECTIVE INTENSITY...WEAK LAPSE RATES WILL GREATLY LIMIT STRONG/SVR
STORM POTENTIAL. THERE WILL BE LOCALLY HEAVY RAINFALL GIVEN MOIST
DEEP LAYER AND SLOW STORM MOVEMENTS. AS WE GO LATER INTO THE EVENING AND
OVERNIGHT...CONVECTION WILL DIMINISH WITH COOLING AND DO NOT EXPECT
FRONTAL LIFT TO SUPPORT MORE THAN STRAY SHOWER ACTIVITY.
FOR SUNDAY INTO SUNDAY NIGHT...THE FRONT AND DEEP LAYER MOISTURE
CONVERGENCE AXIS WILL SET UP OVER MAINLY THE SOUTHEAST HALF OF THE
AREA AS DRIER AIR BEGINS TO SURGE INTO NORTHERN PORTIONS OF THE
ARKLAMISS. HAVE INCREASED POPS FOR SUNDAY AFTERNOON...GIVEN HOT AND
UNSTABLE AIRMASS CHARACTERIZED BY PRECIPITABLE WATER > TWO INCHES
COMBINED WITH PASSAGE OF A WEAK UPPER LEVEL SHORTWAVE TROUGH.
MID LEVEL LAPSE RATES COULD BE SLIGHTLY BETTER THAN TODAY AND
MARGINAL FOR PRODUCING A COUPLE OF SEVERE STORMS...BUT WILL LEAVE
OUT ANY MENTION IN THE HAZARDOUS WEATHER PRODUCTS AT THIS POINT.
/EC/
LONGER TERM DISCUSSION...
MONDAY THROUGH SATURDAY...EXTENDED MODELS AND ENSEMBLES WERE
GENERALLY SIMILAR WITH THE UPCOMING WEATHER PATTERN WITH SOME MINOR
DIFFERENCES. DURING THIS PERIOD THERE WILL BE FLUCTUATIONS OF THE
MEAN RIDGE OVER THE GULF COAST STATES. THIS WILL BE DUE TO SHORT
WAVES MOVING THROUGH THE WESTERLIES JUST NORTH OF THE REGION. THE
WESTERLIES WILL WEAKEN THE MEAN RIDGE WHICH WILL ALLOW A STRONGER
COLD FRONT TO PUSH INTO THE REGION ON THURSDAY. DIURNAL RAIN CHANCES
WILL BE ON THE LOW SIDE FOR THE FIRST HALF OF THE WORK WEEK IN THE
WAKE OF LAST WEEKENDS WEAK FRONT. HOWEVER MOISTURE AND CONVERGENCE
WILL INCREASE (PWATS UP TO AROUND 2 INCHES) ACROSS THE REGION FOR THE
REST OF THE WEEK AHEAD OF THE STRONGER FRONT. THIS WILL INCREASE RAIN
CHANCES FOR THURSDAY INTO FRIDAY BEFORE DRYING OUT FROM THE NORTH ON
SATURDAY IN THE WAKE OF THE FRONT. A COOLER AND DRYER AIRMASS WILL
BUILD ACROSS THE REGION FRIDAY INTO SATURDAY AS DEWPOINTS DROP INTO
THE 50S. THE RAW GFS TRIES TO BRING IN SOME 40S DEWPOINTS FOR A
LITTLE TASTE OF FALL IN THE AIR. TEMPERATURES FRIDAY NIGHT WILL DROP
INTO THE LOWER TO MIDDLE 60S. FOR THE UPCOMING WEEKEND WE MAY SEE
SOME 50S SATURDAY NIGHT WITH HIGHS SUNDAY IN THE 70S.
AS FAR AS TEMPS ARE CONCERNED WENT MAINLY TOWARD MEX GUIDANCE FOR
HIGHS AND LOWS. HIGHS WILL BE IN THE 91-95 FOR MON-WED...89-92 FOR
THUR...THEN COOLING TO 82-90 FOR FRI AND SAT. LOWS WILL BE FROM
66-72 ON MONDAY NIGHT...72-75 FOR TUE AND WED NIGHT...70-72 THURS
NIGHT...BEFORE COOLING INTO THE 60S ON FRIDAY NIGHT. AS FAR AS
POPS ARE CONCERNED WENT CLOSE TO A BLEND OF HPC AND MEX POPS. CUT POPS
FOR SATURDAY WITH DRY AIR BUILDING IN BEHIND THE FRONT./17/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 71 89 70 92 / 28 41 15 15
MERIDIAN 69 91 68 92 / 27 46 18 20
VICKSBURG 70 89 69 91 / 27 35 11 13
HATTIESBURG 72 93 72 93 / 24 54 27 37
NATCHEZ 71 88 70 91 / 27 46 18 24
GREENVILLE 70 88 68 90 / 24 18 7 10
GREENWOOD 70 88 67 90 / 23 20 8 10
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1153 PM CDT THU SEP 4 2014
.SHORT TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 310 PM CDT THU SEP 4 2014
CHANCE FOR SHOWERS AND STORMS TONIGHT...AND COOLER TEMPERATURES TO
FOLLOW...ARE THE PRIMARY SHORT RANGE FORECAST CONCERNS.
COLD FRONT WAS SLIPPING SOUTHEAST THROUGH THE CWA THIS AFTERNOON.
LATEST RAP ANALYSIS SHOWS INSTABILITY INCREASING AHEAD OF THE FRONT
WHERE MLCAPES WERE OVER 3000 J/KG ACROSS SOUTHEAST NEBRASKA AND
SOUTHWEST IOWA. HOWEVER WARM MID LEVEL TEMPERATURES WERE PROVIDING A
CAP FOR STORMS AHEAD OF THE FRONT. BEHIND THE FRONT SCATTERED
SHOWERS AND STORMS HAD DEVELOPED IN SOUTHEAST SOUTH DAKOTA TIED TO
WAVE RIDING THROUGH THE NORTHERN PLAINS...BUT THOSE HAD MOVED OFF TO
THE NORTHEAST OR HAD DISSIPATED BY MID AFTERNOON. GIVEN CAPPING
ALONG AND AHEAD OF FRONT...SEEMS UNLIKELY WE WILL SEE DEVELOPMENT
THERE THIS AFTERNOON OR EVENING. BEHIND THE FRONT...MORE DEVELOPMENT
WILL HAVE TO WAIT UNTIL SHORTWAVE CURRENTLY MOVING INTO EASTERN
COLORADO MOVES INTO OUR AREA. LATEST SHORT RANGE MESOSCALE MODELS
SUGGEST THIS WILL NOT HAPPEN UNTIL LATE THIS EVENING...AND FOCUS ON
AREAS NEAR AND NORTHWEST OF INTERSTATE 80...WITH A GRADUAL DRIFT AND
EXPANSION TO THE SOUTHEAST DURING THE OVERNIGHT.
STRONGER MID LEVEL SHORTWAVE PROVIDING MID LEVEL FRONTOGENESIS IS
FORECAST TO OVERSPREAD THE REGION FRIDAY AFTERNOON AND EVENING
BEFORE MOVING OFF TO THE EAST FRIDAY NIGHT. WILL CONTINUE CHANCE FOR
SHOWERS MUCH OF FRIDAY WITH DECREASING CHANCES FRIDAY NIGHT.
SURFACE HIGH PRESSURE WITH NORTHWEST FLOW ALOFT WILL THEN TAKE OVER
AND BRING MILD AND DRY WEATHER FOR THE BULK OF THE WEEKEND. RETURN
FLOW SETTING UP ON SUNDAY COULD SPREAD MORE CLOUDS INTO THE
REGION...BUT WILL KEEP PRECIPITATION OUT OF THE FORECAST THROUGH THE
AFTERNOON.
COOLER WEATHER IS ALSO ON TAP FOR THE WEEKEND. TEMPERATURES AHEAD OF
COLD FRONT WERE IN THE 90S THIS AFTERNOON...WITH 70S OR EVEN 60S
NOTED IN SOUTH DAKOTA IN DEEPER COLD AIR BEHIND THE FRONT
CORRESPONDING TO 10C 850 TEMPERATURES. THAT AIR WILL SETTLE OVER OUR
AREA FRIDAY AND SATURDAY BEFORE WARMING TO NEAR 14C ON SUNDAY. MODEL
OUTPUT AGREES WITH OUR GOING FORECAST FOR UPPER 60S TO LOWER 70S
FRIDAY AND SATURDAY...WITH MID 70S OR SO ON SUNDAY. SEE NO REASON TO
MOVE FROM THOSE NUMBERS TOO MUCH.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 PM CDT THU SEP 4 2014
UPPER LEVEL FLOW PATTERN WILL BECOME MORE ZONAL FOR THE FIRST HALF
OF THE WEEK BEFORE LARGE UPPER TROUGH SETTLES INTO THE CONUS FOR THE
LATTER HALF. STRONG SHORTWAVE MOVING THROUGH THE PLAINS WILL BRING
RAIN CHANCES TO OUR AREA SUNDAY NIGHT THROUGH MONDAY BEFORE EJECTING
EAST MONDAY NIGHT. RETURN FLOW BEGINNING SUNDAY WILL PROVIDE PLENTY
OF MOISTURE FOR STORMS MONDAY AFTERNOON WHEN SURFACE-BASED CAPES
SHOULD TOP 2000 J/KG AND BULK 0-6KM SHEAR OVER 40KT. SEVERE STORMS
ARE POSSIBLE MONDAY AFTERNOON IF STORMS DO FIRE.
WITH WAVE EXITING TUESDAY...WE SHOULD SEE A DRY PERIOD UNTIL HEIGHTS
BEGIN TO LOWER WEDNESDAY WITH APPROACH OF DEEPER UPPER TROUGH
SETTLING INTO THE PLAINS. CORE OF UPPER TROUGH/LOW WILL MOVE INTO
THE NORTHERN PLAINS BY THURSDAY...AND WILL DRIVE A COLD FRONT
THROUGH OUR AREA WEDNESDAY. ANOTHER CHANCE FOR THUNDERSTORMS WILL
ACCOMPANY THAT FRONT...THEN MAINLY SHOWERS IN OVERRUNNING REGIME
BEHIND THE FRONT FOR WEDNESDAY NIGHT INTO THURSDAY.
TEMPERATURES WILL BE SLOWLY WARMING AHEAD OF WEDNESDAY COLD
FRONT...WITH HIGHS BETWEEN 75 AND 85...THEN MUCH COOLER THURSDAY
WITH HIGHS IN THE 60S.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1149 PM CDT THU SEP 4 2014
AVIATION CONCERNS WILL CONTINUE TO BE SHRA/TSRA. TSRA SHOULD
CONTINUE TO BE SOUTH OF KOFK THROUGH TONIGHT...AND WILL INCLUDE
SHRA/TSRA MENTION AT KOMA AND KLNK INTO THE EARLY MORNING HOURS.
RAIN CHANCES WILL CONTINUE FRIDAY...HOWEVER FOR NOW INCLUDED A
PROB30 AT KOFK LATER FRIDAY MORNING AS ANOTHER SHORTWAVE EMBEDDED
IN THE FLOW AFFECTS THE AREA AND BETWEEN 18 AND 21Z AT KOMA AND
KLNK. SOME OF THE MODELS ARE HINTING AS SOME PATCHY MVFR CIGS
AFTER 18Z...SO WILL NEED TO WATCH THIS. NORTH WINDS 6 TO 12KTS
TONIGHT AND THEN 8 TO 14KTS DURING THE DAY FRIDAY.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
924 PM MDT SAT SEP 6 2014
.UPDATE...
QUICK UPDATE TO ADD FOG TO THE EAST SLOPES CENTRAL MT CHAIN AND
OVER PORTIONS OF THE EASTERN PLAINS TONIGHT. ALSO TRIMMED POPS FOR
THE EVENING WITH MAJORITY OF ECHOES DIMINISHING...AND HRRR CONCURS
THERE MAY BE ONLY A FEW SHOWERS LINGERING DURING THE
OVERNIGHT...DESPITE THE 00Z MET GUIDANCE CHANCE POPS FOR PORTIONS
OF THE SOUTH CENTRAL AND SOUTHEAST. TWEAKED A FEW MIN TEMPERATURES
HIGHER WHERE DEW POINTS APPEAR THEY WON/T FALL MUCH MORE THAN
CURRENT VALUES. ONE QUESTION IS HOW MUCH IF ANY LOW CLOUDS MAY
SEEP INTO THE RGV...IT DOES APPEAR KSAF WILL HAVE ANOTHER SHOT
TONIGHT...AND MAYBE LOCALES FROM KABQ SOUTH.
&&
.PREV DISCUSSION...609 PM MDT SAT SEP 6 2014...
.AVIATION...
00Z TAF CYCLE
THOUGH FOG DIMINISHED ACROSS THE EAST TODAY...THE STRATUS DECK WAS
STUBBORN AND REMAINED IN PLACE OVER MUCH OF THE EASTERN HIGHLANDS
AND PLAINS. LOOK FOR THE STRATUS TO FILL IN A BIT OVER EASTERN
AREAS THAT DID CLEAR DURING THE OVERNIGHT...WITH CEILINGS LOWERING
TO MVFR THRESHOLDS WITH OCCASIONAL IFR CEILING AND VISIBILITIES
OVERNIGHT AND EARLY MORNING ESPECIALLY EASTERN HIGHLANDS SOUTH OF
INTERSTATE 40 AND ALONG THE INTERSTATE 25 CORRIDOR FROM KLVS TO
KRTN. ADDITIONALLY...ISOLATED THUNDERSTORMS WILL LINGER THIS
EVENING OVER THE NORTHERN AND SOUTHWEST HIGH TERRAIN...PRODUCING
LOCAL MVFR CEILINGS AND VISIBILITIES AND POSSIBLY SOME GUSTY
OUTFLOWS THROUGH AROUND 06Z. SHOWERS COULD LINGER OVER THE
SOUTHWEST ZONES OVERNIGHT. LOOK FOR ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS TO FAVOR THE HIGHER TERRAIN AND SOUTHEAST PLAINS
ON SUNDAY...WITH THE STRATUS DECK GRADUALLY LIFTING BUT GENERALLY
PERSISTING IN THE EAST.
05
&&
.PREV DISCUSSION...332 PM MDT SAT SEP 6 2014...
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL BE LIMITED PRIMARILY ACROSS THE
WESTERN AND NORTHERN HIGH TERRAIN TODAY...THOUGH MODERATE TO HEAVY
RAIN SHOWERS ARE POSSIBLE FOR PORTIONS OF THE SOUTHEAST PLAINS.
STORM ACTIVITY WILL SHIFT TO THE WEST SUNDAY WHILE THE EAST
EXPERIENCES WARMER TEMPERATURES AND CLEARER SKIES. AN UPPER LEVEL
TROUGH WILL CROSS THE STATE MONDAY INTO TUESDAY...DRAGGING MOISTURE
FROM HURRICANE NORBERT NORTH. THIS WILL RESULT IN ANOTHER PERIOD OF
POTENTIALLY HEAVY RAINS FOR MUCH OF WESTERN AND NORTHERN NEW
MEXICO. AS DRYING COMMENCES ACROSS THE WEST WEDNESDAY AND
THURSDAY...A POTENT BACKDOOR COLD FRONT COULD BRING UNSEASONABLY
COOLER TEMPERATURES AND INCREASED STORM ACTIVITY TO THE EASTERN
PLAINS.
&&
.DISCUSSION...
CURRENTLY SATELLITE IMAGERY SHOWS THE LOW CLOUD DECK HANGING IN
TOUGH ACROSS THE EASTERN PLAINS...WITH ONLY GRADUAL CLEARING
OCCURRING ACROSS THE FAR NE. ISOLATED STORMS ARE DEVELOPING ACROSS
THE WESTERN AND NORTHERN HIGH TERRAIN WITH LITTLE TO NO MOVEMENT.
ONE AREA TO MONITOR IS A SWATH OF MODERATE TO HEAVY RAIN SHOWERS
SLOWLY MOVING NORTHWEST FROM THE CARLSBAD AREA. IF IT HOLDS
TOGETHER...IT COULD BRING HEAVY RAIN ACROSS PORTIONS OF CHAVES AND
SE LINCOLN COUNTIES. LOW CLOUDS WILL PERSIST OVERNIGHT OUT
EAST...THOUGH CONFIDENCE NOT HIGH ENOUGH TO ADD PATCHY FOG WORDING
INTO THE ZONES. THE STORM FOCUS WILL SHIFT WEST SUNDAY AS THE
UPPER LEVEL HIGH SHIFTS EAST. COOLER TEMPERATURES DUE TO CLOUD
COVER IS EXPECTED OUT WEST WITH SIGNIFICANT WARMING EAST. SOME
LOCALLY HEAVY RAIN WILL BE POSSIBLE...BUT MOISTURE ACROSS THE AREA
WILL TREND DOWN.
MONDAY AND TUESDAY WILL BE THE NEXT SIGNIFICANT PERIOD. THE UPPER
LEVEL HIGH WILL CONTINUE SHIFT SOUTHEAST AS AN UPPER LEVEL TROUGH SLOWLY
MOVES EAST ACROSS THE DESERT SW. MOISTURE FROM HURRICANE NORBERT
WILL WORK NORTH AHEAD OF THE TROUGH...INCREASING PWATS
SIGNIFICANTLY ACROSS THE AREA. MORE ROBUST SHOWER AND THUNDERSTORM
ACTIVITY WILL RESULT...FOCUSING ACROSS WESTERN AND NORTHERN NM
THROUGH TUESDAY AFTERNOON. DESPITE THE SIGNIFICANT INCREASE IN
MOISTURE...STORM MOTION AROUND 25 MPH AND LACK OF TRAINING
LOWERED CONFIDENCE OF POTENTIAL A FLASH FLOOD RISK. WILL HOLD OFF
ON ISSUING ANY PRODUCT FOR NOW. BY TUESDAY...TEMPERATURES WILL DO
A FLIP...WITH WESTERN NM BECOMING BELOW NORMAL AND THE EAST
REACHING ABOVE NORMAL LEVELS. WINDS WILL INCREASE MONDAY INTO
TUESDAY DUE TO INCREASING WESTERLY WINDS ALOFT AND A DEEPENING
LEE SIDE TROUGH.
MODELS ARE IN DECENT AGREEMENT THAT PORTIONS OF THE FORECAST AREA
WILL GET THE FIRST TASTE OF FALL WEATHER BY LATE WEEK. A BACKDOOR
COLD FRONT WILL ENTER THE NORTHEAST PLAINS BY WEDNESDAY AFTERNOON
WITH A REINFORCING SHOT THURSDAY MORNING. IT WILL BRING A BOOST IN
LOW LEVEL MOISTURE AND MUCH COOLER AIR. COMBINED WITH A WEAK
SAGGING TROUGH OVERHEAD AND COOLER AIR ALOFT...THIS COULD MAKE FOR
THE COOLEST OVERNIGHT LOWS SINCE SUMMER STARTED. CONFIDENCE
REMAINS LOW ON SPECIFIC DETAILS AS MODELS DIFFER SLIGHTLY ON
TIMING OF INITIAL AND SECONDARY PUSH...WHICH ALSO IMPACTS THE
AREAS OF STORM ACTIVITY. SO LOWERED POPS FOR NOW DUE TO LOWERED
CONFIDENCE...BUT MAINTAINED COOL LATE WEEK HIGHS AND LOWS.
&&
.FIRE WEATHER...
WHILE CRITICAL FIRE WEATHER CONDITIONS WILL NOT BE MET ACROSS
NORTH AND CENTRAL NM FOR AT LEAST THE NEXT WEEK AND LIKELY EVEN
LONGER... PORTIONS OF EAST CENTRAL AND NE NM WILL SEE NEAR SFC
WINDS REACH OR AT LEAST APPROACH LOW END CRITICAL LEVELS TUE AFTN.
MINIMUM RH THOUGH SHOULD STAY 10 TO PERHAPS 15 PERCENT ABOVE
CRITICAL VALUES. REST OF THIS WEEKEND BE MUCH MORE DRY THAN WET
WITH THE NORTHERN AND WESTERN HIGHER TERRAIN SEEING A FEW AFTN AND
EVE SHOWERS AND STORMS WHILE FAR SOUTHERN REACHES OF FIRE WX ZONES
107 AND 108 POSSIBLY SEEING A BIT OF DRIZZLE OR LIGHT RAIN AT
TIMES TONIGHT INTO SUN. SE HALF TO TWO THIRDS OF FCST AREA TO
REMAIN COOLER THAN AVERAGE SUN WITH LOW CLOUDS EXPECTED SLOWLY
ERODE FROM NORTH TO SOUTH. ADDITIONAL RAINFALL AMOUNTS WILL BE ON
THE LOW SIDE EVEN WITH ANY STORMS...GENERALLY A QUARTER INCH OR
LESS. TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW AVERAGE IN THE
DIVIDE REGION TODAY WITH MINIMUM RH RANGING FROM 25 TO 45 PERCENT.
EXPECT STRONGEST WINDS TO BE JUST WEST OF CANYONS AND LOWER PASSES
ALONG CENTRAL MTN CHAIN THAT ARE NORMALLY PRONE TO GUSTY GAP
WINDS...ESPECIALLY THIS EVENING.
BY MON A DEEPER AND FAIRLY ROBUST SURGE IN MOISTURE IS EXPECTED TO
INVADE WESTERN NM...BRINGING A MAJOR INCREASE IN WETTING RAINFALL
WEST OF THE RIO GRANDE WITH MORE ISOLATED ACTIVITY FARTHER EAST.
HIGH TEMPS MON WILL BE SUBNORMAL IN ROUGHLY THE WEST HALF OF FCST
AREA MOSTLY DUE TO THE INCREASED CLOUD COVER AND RAIN AREAS. AN
APPROACHING SHORT WAVE TROUGH ALOFT EMBEDDED IN THE INCREASINGLY
WESTERLY FLOW SHOULD ALSO AID IN RAIN AND EMBEDDED STORM
DEVELOPMENT. A LEE SIDE SURFACE TROUGH WILL ALSO DEVELOP MONDAY
AFTERNOON...INDUCING SOME BREEZES IN THE EAST/NORTHEAST.
TUE LOOKS A LITTLE MUDDLED STILL...BUT THE BASIC PREMISE WILL BE A
DEEPER WEST COAST TROUGH SHIFTING EAST TOWARD AZ WHILE DRAWING IN
SOME LINGERING...BUT REDUCED...TROPICAL MOISTURE FROM THE REMNANTS
OF FORMER HURRICANE NORBERT. SHOULD MAINTAIN A RATHER MOIST AND
SLIGHTLY COOLER THAN AVERAGE ATMOSPHERE IN THE WEST TUE WITH STILL A
FAIRLY DECENT CROP OF STORMS POSSIBLE...WHILE PORTIONS OF THE EAST
WILL EXPERIENCE THE AFOREMENTIONED NEAR TO MARGINALLY CRITICAL WIND
SPEEDS IN THE AFTN...THOUGH WITH NON CRITICAL RH. BRIEF WINDOW FOR
DRYING/WARMING ON WEDNESDAY WOULD QUICKLY BE EXCHANGED FOR MAJOR
COOLING...ESPECIALLY EAST...BY THU OR EARLY FRI AS A STRONG BACK
DOOR COLD FRONT RUSHES IN...DRAGGING IN SOME ADDITIONAL LOWER LVL
MOISTURE. THERE ARE SOME TIMING DIFFERENCES BETWEEN EXTENDED MODELS
AS TO THE ARRIVAL OF THIS FRONT.
43
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
141 PM EDT FRI SEP 5 2014
.SYNOPSIS...
HIGH PRESSURE ALONG THE EAST COAST WILL PROVIDE A VERY WARM AND HUMID
SUMMER LIKE AFTERNOON FOR THE REGION. THERE IS A CHANCE FOR
AFTERNOON SHOWERS AND THUNDERSTORMS ESPECIALLY IN NORTHEAST
PENNSYLVANIA AND ALSO IN NORTH CENTRAL NEW YORK. AN APPROACHING
COLD FRONT WILL BRING THE LIKELIHOOD OF MORE SHOWERS AND
THUNDERSTORMS, STARTING LATE TONIGHT, THEN LASTING THROUGH MUCH OF
SATURDAY. ONCE THIS FRONT PUSHES OFF THE COAST, A NEW HIGH
PRESSURE SYSTEM WILL ADVANCE TOWARD THE REGION SUNDAY, WITH DRIER
AND COOLER WEATHER.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL WAVE MOVING ACRS THE
OHIO VALLEY WHICH WAS SUPPORTG SOME CONVECTIVE ACVTY OVER THE
UPPER LAKES. THE SOUTHERN EDGE OF THIS WAS AFFECTING SRN ONT AND
LAKE ONTARIO AT THIS TIME. THIS ACVTY WAS MOVING EASTWARD AS THE
UPPER LEVEL WAVE PROPAGATES TO THE E-NE THIS AFTERNOON. THE
GFS...NAM...EURO...CMC AND RAP ALL SHOW THIS UPPER LEVEL FEATURE
WORKING ACRS NY AND PA BTWN 18Z AND 00Z WITH ONLY SOME SLIGHT
COOLING ALOFT ON THE ORDER OF BARELY 1C AT 500 MB. THIS WILL OCCUR
IN CONCERT WITH THE MAX HEATING OF THE AFTERNOON AND FAIRLY RICH
BOUNDARY LAYER MOISTURE ESPECIALLY ALONG THE LAKE ONTARIO PLAIN
AND IN NE PA. HENCE WHERE THERE IS ENUF INSTABILITY THERE WILL BE
A FEW SHRA OR TSRA POPPING UP.
MODEL INSTABILITY FIELDS FROM THE RAP...GFS...NAM ALSO SHOW A
RIBBON OF INSTABILITY OVER 1000 J/KG ALONG THE LAKE ONTARIO PLAIN
AS WELL AS ACRS NE PA WHERE CAPES CUD EXCEED 2000 J/KG (AS PER 06Z
NAM AT LEAST) WITH A MINIMUM IN CAPE ACROSS FAR NRN PA AND SC NY.
BELIEVE SOME ISLD TO SCT TSRA WILL FIRE THIS AFTERNOON WHEN THIS
WAVE INTERACTS WITHIN THESE INSTABILITY AXISES WITH COVERAGE IN
THE ISLD TO SCT RANGE IN NC NY AND NE PA SO HAVE ADDED POPS FOR
LATER TODAY IN NE PA TO ACCOUNT FOR. JUST TWEAKED POPS IN NC NY
FROM EARLIER SHIFT. 06Z NAM SOUNDING ACTUALLY HAS 3000 J/KG OF
CAPE AT AVP ARND 22-00Z! THE FORCING IS WEAK BUT IF SOMETHING
FIRES THERE CUD BE SOME VERY HEAVY RAIN LOCALLY WITH PWATS AROUND
1.75 INCHES AND THE POTENTIAL FOR STORMS TO ANCHOR ON THE
MOUNTAINS IN SUCH A WEAK FLOW REGIME. THE WINDS ARE STRONGER IN
THE LOW-LEVELS BETWEEN 0 AND 3 KM THEN WEAKEN ARND 3 TO 6 KM AND
THEN STRENGTHEN AGAIN. WE WILL HAVE TO WATCH THIS CAREFULLY THIS
AFTERNOON. ANYTHING THAT FIRES DOWN IN NE PA CUD CAUSE HEAVY RAIN.
AND.... IF CAPE VALUES ACTUALLY REACH 3000 J/KG AS PER 06Z NAM YOU
CANT RULE OUT A MICROBURST...EVEN IF CAPES EXCEED 2000 J/KG. WILL
MENTION IN HWO FOR NE PA THIS AFTERNOON. FARTHER N IN NC NY...ACVTY
LIKELY WILL BE MORE ISOLATED WITH LESS INSTABILITY. BUT THERE WAS STRGR
WIND FIELDS. THIS LIKELY WILL LESSENING THREAT FOR ANY SLOW MOVING HEAVY
RAIN PRODUCING STORMS. CAPES CUD REACH 500 TO 1000 J/KG WITH SOME
LOW-LEVEL SHEAR ARND 15-20 KNOTS BUT WEAKER DEEP LAYER SHEAR. NOT
EXPECTING ANY ORGANIZED SVR ACVTY IN NC NY AS A RESULT UNLESS
CAPES GET HIGHER THAN PROJECTED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
430 AM UPDATE... OVERALL...MODEL GUIDANCE REMAINS SIMILAR TO THE
LAST SVRL RUNS...IN SHOWING AN ADVANCING SFC COLD FRNT THROUGH THE
AREA ON SAT...FOLLOWED BY HIGH PRES AND S/WV RIDGING ALOFT SUN.
SHWRS/TSTMS ALG AND AHD OF THE COLD FRNT SHOULD INCREASE IN
COVERAGE LTR TNT OVER OUR NRN AND WRN ZNS...WITH A BAND OF FAIRLY
WIDESPREAD CONVECTION PUSHING SEWD THROUGH CNY/NE PA DURG THE DAY
SAT. WE`LL CONTINUE TO EMPLOY LIKELY POPS FOR MUCH OF THIS TIME
FRAME.
THE POTENTIAL FOR STG/SVR STORMS ON SAT LOOKS MUDDLED OVER THE
FA...WITH SIG CLOUD COVER LIKELY TO LIMIT DESTABILIZATION FOR AT
LEAST THE NWRN HALF OF THE CWA (CNTRL SRN TIER...FINGER LKS...WRN
MOHAWK VLY...AND SRN TUG HILL RGNS OF NY). HOWEVER...FARTHER S AND
E...THERE ARE NOW SOME INDICATIONS THAT THE SFC BNDRY MAY SLOW
JUST ENUF (ROUGHLY AN 18-21Z FROPA) TO ALLOW SOME MODEST HEATING
(TEMPS INTO THE LWR 80S)...WITH PROGGED ML CAPES IN THE
NEIGHBORHOOD OF 1000 J/KG. GIVEN DEEP-LYRD SHEAR OF 25-30 KT BY
THIS TIME...THE ENVIR COULD BECOME MARGINALLY SUPPORTIVE OF STG
GUSTY WINDS. THUS...WE`VE HIGHLIGHTED THIS POTENTIAL IN THE HWO
SAT FOR OUR FAR ERN AND SRN ZNS (OTSEGO CNTY...THE WRN
CATSKILLS...THE POCONOS...AND THE WILKES-BARRE SCRANTON AREA).
SPURRED ON BY A FAIRLY AMPLIFIED S/WV...THE COLD FRNT SHOULD
PROGRESS OFF THE COAST SAT NIGHT...WITH ANY LINGERING CONVECTION
ENDING EARLY IN THE EVE.
SUN SHOULD BE COOLER (HIGHS MAINLY IN THE 70-75 RANGE)...UNDER PTLY TO
MOSTLY SUNNY SKIES...WITH A SFC RIDGE BLDG IN FROM THE W.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
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 /17Z FRIDAY THROUGH TUESDAY/...
18Z UPDATE...
FEW-SCT CIRRUS CLOUDS DRIFTING THRU THIS AFTN WITH AN OCNL VFR
CUMULUS DEVELOPING BUT NOT ENOUGH FOR AVIATION CONCERNS. EXPECT
VFR TO CONTINUE THROUGH THE PRE-DAWN HOURS. COLD FRONT WILL
APPROACH FROM THE NORTH AND WEST AND LOW CLOUDS MAY DEVELOP AHEAD
OF THIS FEATURE, HOWEVER CONFIDENCE ON THIS OCCURRING IS NOT
HIGH. THUS HAVE TEMPO`D IN LOW MVFR RESTRICTION TO ELM BETWEEN 09Z
AND 12Z AS CHANCES FOR FOG WILL EXIST IF CLOUDS DO NOT DEVELOP.
-SHRA LOOKS TO HOLD OFF UNTIL AFTER 13Z ACROSS NRN NY TERMINALS
(SYR AND RME). -SHRA EXPECTED AT REMAINING NY TERMINALS BETWEEN
14Z AND 18Z WITH AVP REMAINING OUT OF -SHRA UNTIL AFTER 18Z.
THUNDER LOOKS POSSIBLE AT SOUTHERN TERMINALS (ITH, ELM, BGM AND
AVP) BUT HAVE HELD OFF ON MENTION IN TAFS AT THIS TIME.
WINDS OUT OF THE SSW AROUND 10KTS WILL BECOME LIGHT OVERNIGHT
INCREASE TO 5-10KTS FROM THE SOUTH OUT OF THE SSW AHEAD OF THE
FRONT BY MORNING.
OUTLOOK...
SAT NIGHT...MVFR RESTRICTIONS POSSIBLE BEHIND FRONT.
SUN-TUE...MOSTLY VFR WITH POTENTIAL FOR IFR RESTRICTIONS EACH
MORNING, ESPECIALLY ELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN/MLJ
NEAR TERM...DJN
SHORT TERM...MLJ
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1009 AM EDT FRI SEP 5 2014
.SYNOPSIS...
HIGH PRESSURE ALONG THE EAST COAST WILL PROVIDE A VERY WARM AND HUMID
SUMMER LIKE AFTERNOON FOR THE REGION. THERE IS A CHANCE FOR
AFTERNOON SHOWERS AND THUNDERSTORMS ESPECIALLY IN NORTHEAST
PENNSYLVANIA AND ALSO IN NORTH CENTRAL NEW YORK. AN APPROACHING
COLD FRONT WILL BRING THE LIKELIHOOD OF MORE SHOWERS AND
THUNDERSTORMS, STARTING LATE TONIGHT, THEN LASTING THROUGH MUCH OF
SATURDAY. ONCE THIS FRONT PUSHES OFF THE COAST, A NEW HIGH
PRESSURE SYSTEM WILL ADVANCE TOWARD THE REGION SUNDAY, WITH DRIER
AND COOLER WEATHER.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL WAVE MOVING ACRS THE
OHIO VALLEY WHICH WAS SUPPORTG SOME CONVECTIVE ACVTY OVER THE
UPPER LAKES. THE SOUTHERN EDGE OF THIS WAS AFFECTING SRN ONT AND
LAKE ONTARIO AT THIS TIME. THIS ACVTY WAS MOVING EASTWARD AS THE
UPPER LEVEL WAVE PROPAGATES TO THE E-NE THIS AFTERNOON. THE
GFS...NAM...EURO...CMC AND RAP ALL SHOW THIS UPPER LEVEL FEATURE
WORKING ACRS NY AND PA BTWN 18Z AND 00Z WITH ONLY SOME SLIGHT
COOLING ALOFT ON THE ORDER OF BARELY 1C AT 500 MB. THIS WILL OCCUR
IN CONCERT WITH THE MAX HEATING OF THE AFTERNOON AND FAIRLY RICH
BOUNDARY LAYER MOISTURE ESPECIALLY ALONG THE LAKE ONTARIO PLAIN
AND IN NE PA. HENCE WHERE THERE IS ENUF INSTABILITY THERE WILL BE
A FEW SHRA OR TSRA POPPING UP.
MODEL INSTABILITY FIELDS FROM THE RAP...GFS...NAM ALSO SHOW A
RIBBON OF INSTABILITY OVER 1000 J/KG ALONG THE LAKE ONTARIO PLAIN
AS WELL AS ACRS NE PA WHERE CAPES CUD EXCEED 2000 J/KG (AS PER 06Z
NAM AT LEAST) WITH A MINIMUM IN CAPE ACROSS FAR NRN PA AND SC NY.
BELIEVE SOME ISLD TO SCT TSRA WILL FIRE THIS AFTERNOON WHEN THIS
WAVE INTERACTS WITHIN THESE INSTABILITY AXISES WITH COVERAGE IN
THE ISLD TO SCT RANGE IN NC NY AND NE PA SO HAVE ADDED POPS FOR
LATER TODAY IN NE PA TO ACCOUNT FOR. JUST TWEAKED POPS IN NC NY
FROM EARLIER SHIFT. 06Z NAM SOUNDING ACTUALLY HAS 3000 J/KG OF
CAPE AT AVP ARND 22-00Z! THE FORCING IS WEAK BUT IF SOMETHING
FIRES THERE CUD BE SOME VERY HEAVY RAIN LOCALLY WITH PWATS AROUND
1.75 INCHES AND THE POTENTIAL FOR STORMS TO ANCHOR ON THE
MOUNTAINS IN SUCH A WEAK FLOW REGIME. THE WINDS ARE STRONGER IN
THE LOW-LEVELS BETWEEN 0 AND 3 KM THEN WEAKEN ARND 3 TO 6 KM AND
THEN STRENGTHEN AGAIN. WE WILL HAVE TO WATCH THIS CAREFULLY THIS
AFTERNOON. ANYTHING THAT FIRES DOWN IN NE PA CUD CAUSE HEAVY RAIN.
AND.... IF CAPE VALUES ACTUALLY REACH 3000 J/KG AS PER 06Z NAM YOU
CANT RULE OUT A MICROBURST...EVEN IF CAPES EXCEED 2000 J/KG. WILL
MENTION IN HWO FOR NE PA THIS AFTERNOON. FARTHER N IN NC NY...ACVTY
LIKELY WILL BE MORE ISOLATED WITH LESS INSTABILITY. BUT THERE WAS STRGR
WIND FIELDS. THIS LIKELY WILL LESSENING THREAT FOR ANY SLOW MOVING HEAVY
RAIN PRODUCING STORMS. CAPES CUD REACH 500 TO 1000 J/KG WITH SOME
LOW-LEVEL SHEAR ARND 15-20 KNOTS BUT WEAKER DEEP LAYER SHEAR. NOT
EXPECTING ANY ORGANIZED SVR ACVTY IN NC NY AS A RESULT UNLESS
CAPES GET HIGHER THAN PROJECTED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
430 AM UPDATE... OVERALL...MODEL GUIDANCE REMAINS SIMILAR TO THE
LAST SVRL RUNS...IN SHOWING AN ADVANCING SFC COLD FRNT THROUGH THE
AREA ON SAT...FOLLOWED BY HIGH PRES AND S/WV RIDGING ALOFT SUN.
SHWRS/TSTMS ALG AND AHD OF THE COLD FRNT SHOULD INCREASE IN
COVERAGE LTR TNT OVER OUR NRN AND WRN ZNS...WITH A BAND OF FAIRLY
WIDESPREAD CONVECTION PUSHING SEWD THROUGH CNY/NE PA DURG THE DAY
SAT. WE`LL CONTINUE TO EMPLOY LIKELY POPS FOR MUCH OF THIS TIME
FRAME.
THE POTENTIAL FOR STG/SVR STORMS ON SAT LOOKS MUDDLED OVER THE
FA...WITH SIG CLOUD COVER LIKELY TO LIMIT DESTABILIZATION FOR AT
LEAST THE NWRN HALF OF THE CWA (CNTRL SRN TIER...FINGER LKS...WRN
MOHAWK VLY...AND SRN TUG HILL RGNS OF NY). HOWEVER...FARTHER S AND
E...THERE ARE NOW SOME INDICATIONS THAT THE SFC BNDRY MAY SLOW
JUST ENUF (ROUGHLY AN 18-21Z FROPA) TO ALLOW SOME MODEST HEATING
(TEMPS INTO THE LWR 80S)...WITH PROGGED ML CAPES IN THE
NEIGHBORHOOD OF 1000 J/KG. GIVEN DEEP-LYRD SHEAR OF 25-30 KT BY
THIS TIME...THE ENVIR COULD BECOME MARGINALLY SUPPORTIVE OF STG
GUSTY WINDS. THUS...WE`VE HIGHLIGHTED THIS POTENTIAL IN THE HWO
SAT FOR OUR FAR ERN AND SRN ZNS (OTSEGO CNTY...THE WRN
CATSKILLS...THE POCONOS...AND THE WILKES-BARRE SCRANTON AREA).
SPURRED ON BY A FAIRLY AMPLIFIED S/WV...THE COLD FRNT SHOULD
PROGRESS OFF THE COAST SAT NIGHT...WITH ANY LINGERING CONVECTION
ENDING EARLY IN THE EVE.
SUN SHOULD BE COOLER (HIGHS MAINLY IN THE 70-75 RANGE)...UNDER PTLY TO
MOSTLY SUNNY SKIES...WITH A SFC RIDGE BLDG IN FROM THE W.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
130 PM UPDATE...
SPRAWLING HIGH PRESSURE WILL INFLUENCE THE REGION`S WX FOR THE
FIRST SVRL DAYS OF THE LONG TERM. SYNOPTIC PATTERN WL TRANSITION
FM ZONAL FLOW ALOFT TO SWRLY FLOW BY MID-WEEK AS ANOTHER S/WV TROF
TRACKS IN FM THE UPR MIDWEST. THIS WL SPELL OUR NEXT CHC FOR
SHOWERS/TSTMS ON RETURN FLOW ASSOC WITH SFC TROF AND ULTIMATELY
LOPRES RIDING UP SPINE OF THE APPALACHIANS. THIS WL KEEP AREA IN
MOIST/CLDY AIRMASS WITH CHC POPS EACH PD THRU END OF EXTNDD PD
LOWS IN THE 50S/HIGHS IN THE 70S WHICH IS TYPICAL FOR THIS TIME OF
YR.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
RESTRICTIONS EXPECTED AT KELM AND KAVP THIS MORNING, OTHERWISE VFR
THROUGH TONIGHT.
AT KELM DENSE FOG HAS FINALLY SET IN WITH VLIFR VSBYS/CIGS THROUGH
13Z, AND A SLOW IMPROVEMENT TO VFR BY 14Z. AT KAVP A MARINE LAYER
THAT HAS PRODUCED MVFR CIGS WILL SLOWLY BREAK UP BY 13Z.
FOR THE REST OF TODAY HIGH CLOUDS ESPECIALLY OVER THE NY TERMINALS
WILL GRADUALLY LOWER TONIGHT TO AROUND 10KFT. SHOWERS POSSIBLE NY
TERMINALS TOWARD DAYBREAK SATURDAY.
OUTLOOK...
SAT...MVFR/IFR LIKELY IN OCNL SHRA/TSRA.
SUN-TUE...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...MLJ
LONG TERM...PVN
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1143 PM EDT SAT SEP 6 2014
.SYNOPSIS...
EXPECT A WET 24 TO 48 HOUR PERIOD THROUGH MONDAY AS WAVES OF
SHOWERS AND THUNDERSTORMS WITH HEAVY RAINFALL OCCASIONALLY PUSH
ACROSS THE AREA. THIS IN RESPONSE TO A SLOW MOVING COLD FRONT
DROPPING SOUTHEAST...AND AN AREA OF LOW PRESSURE SLOWLY MOVING
NORTHEAST ALONG THE SOUTHEAST U.S. COAST. THE LOW WILL EXIT THE
REGION LATE MONDAY NIGHT...FOLLOWED BY A GRADUAL WARMING AND
DRYING TREND THROUGH THE UPCOMING MID TO LATE WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 1100 PM SATURDAY...HAVE MASSAGED THE POPS FROM THE PREVIOUS
UPDATE...WITH AN INCREASING COVERAGE OF ONSHORE MOVING CONVECTION.
GOOD CHANCE TO LIKELY POP CATEGORIES FOR THE IMMEDIATE COAST BY
DAYBREAK SUN...LOWERING AS ONE PROGRESSES INLAND. THE TROPICAL
REGIME WARRANTS A SLIGHT TWEAK UPWARDS OF THE SFC DEWPOINTS BASED
ON LATEST OBS AND TRENDS.
PREVIOUS DISCUSSION...............................................
AS OF 700 PM SATURDAY...DID NOT THINK THAT THE ILM CWA WOULD BE
NEARLY PCPN-FREE AT THIS TIME. KLTX 88D IS OBS AND TRENDS CONFIRM
THIS CONVECTION FREE TIME FOR THE MOMENT. DETAILED HOURLY MODEL
MODEL DATA HAS SOMEWHAT CAUGHT UP...IE. THE HRRR MODEL...AND IT
SAYS THAT THE REMAINDER OF THIS EVENING LOOKS TO REMAIN PCPN
FREE...ESPECIALLY INLAND. HOWEVER...THE HRRR SEEMS OVERDONE WITH
ONSHORE MOVEMENT OF PCPN THIS EVENING ESPECIALLY WHEN COMPARING
THE LATEST HRRR REFLECTIVITY WITH CURRENT KLTX 88D RADAR DATA. AS
A RESULT...HAVE LOWERED POPS BY UP TO A SEVERAL CATEGORIES FOR THE
REMAINDER OF THIS EVENING. THE HRRR AND ESPECIALLY THE LATEST NAM
CONTINUE WITH INCREASING DEVELOPMENT OF NOCTURNAL ATL CONVECTION
ALONG OUR ADJACENT COASTAL AND OFFSHORE WATERS AFTER
MIDNIGHT...AND THEIR ONSHORE MOVEMENT DURING THE SUNDAY PRE-DAWN
HRS. WILL RAMP POPS BACK UP ACROSS THE FA...MAINLY ACROSS THE
COASTAL COUNTIES WITH A SLOWER INCREASING POP TREND LEADING UP TO
THE I-95 CORRIDOR. HAVE ALSO DECREASED CLOUDINESS ACROSS THE FA
FOR THIS EVENING. HAVE NOT INTRODUCED FOG AT THE MOMENT BUT IF THE
FA EXPERIENCES AN EXTENDED PERIOD OF MOSTLY CLEAR SKIES THIS
EVENING AND/OR OVERNIGHT...FOG MAY BECOME AN ISSUE. HAVE TWEAKED
VERY LITTLE WITH TONIGHTS LOWS...LOOK AOK EVEN WITH A MOSTLY CLEAR
SKIES AT TIMES. TROPICAL AIR MASS REMAINS IN PLACE...WITH SFC
DEWPOINTS REMAINING IN THE LOW TO MID 70S.
PREVIOUS DISCUSSION...........................
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 /6 AM SUNDAY MORNING 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 /03Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...THE RADAR IS QUIET THIS EVENING SO WE CAN EXPECT A LULL
IN PCPN EARLY TONIGHT. A WEAK SFC LOW NEAR THE GA/SC COAST WILL
SLOWLY MOVE NORTHEAST OVERNIGHT...AND THE HRRR INDICATES MORE SHOWER
ACTIVITY WILL SPREAD UP THE COAST AFTER 06Z SUN. THIS COULD RESULT
IN TEMPO MVFR CIGS/VSBYS AT THE COASTAL TERMS EARLY SUN MORNING.
HAVE NOT INCLUDED VCSH FOR KFLO/KLBT AS THE HI-RES GUIDANCE AND SREF
PROBS INDICATE PCPN WILL MAINLY BE CONFINED TO THE COAST. BUT THE
RELATIVE LACK OF CLOUD COVER INLAND COULD RESULT IN IFR CIGS AND/OR
VSBYS AROUND DAYBREAK AT KFLO/KLBT. SINCE CONFIDENCE IS STILL LOW
ATTM...WILL INCLUDE MVFR VSBYS AND SCT 500 FT STRATUS AND REEVALUATE
WITH THE NEXT ISSUANCE. EXPECT WIDESPREAD SHOWERS DURING THE DAY SUN
AS TROPICAL MOISTURE STREAMS ONSHORE AND A COLD FRONT ENTERS OUR
CWA. THERE WILL LIKELY BE SOME MVFR/IFR VSBYS IN LOCALLY HEAVIER
SHOWERS...BUT FOR NOW WILL CARRY 6SM SHRA AND MVFR CIGS FOR ALL
TERMINALS THROUGH THE DAY.
EXTENDED OUTLOOK...SHOWERS WITH PERIODS OF MVFR CIGS AND MVFR/IFR
VSBYS THROUGH MONDAY. VFR TUESDAY THROUGH THURSDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1115 PM SATURDAY...BORDERLINE SCEC CONDITIONS REMAIN AND
WILL CONTINUE WITH IT THRU 600 PM SUNDAY. LATEST HRRR CONTINUES TO
SUPPORT WIND-WISE WITH RESULTING SEAS FOLLOWING.
PCPN COVERAGE CONTINUES TO INCREASE ACROSS THE ADJACENT ATL
WATERS. TRAJECTORIES SO FAR SHOW THE PCPN MOVING MAINLY PARALLEL
TO THE ILM COAST...AND NOT DIRECTLY ONSHORE. HOWEVER...AS THE
WEAKNESS SFC AND ALOFT ALONG THE SC-GA COAST MOVES SLOWLY NE-
WARD...EXPECT THE ATL PCPN BEGIN TO TRACK MORE NORTHERLY OR EVEN
NNW. AS A RESULT...THE CONVECTION WILL BECOME MORE WIDESPREAD
ACROSS THE ILM WATERS THRU DAYBREAK.
PREVIOUS DISCUSSION,...........................................
AS OF 845 PM SATURDAY...HAVE RAISED A BORDERLINE SCEC FOR ALL
WATERS TONIGHT INTO SUNDAY. LATEST WIND AND SFC OBS ACROSS THE
LOCAL WATERS AS MENTIONED IN THE EARLIER UPDATE...ARE BASICALLY
5 KT AND 1 FOOT AWAY FROM A BORDERLINE SCEC. LATEST HRRR AND NAM
STILL INDICATE A SUSTAINED 15 TO OCCASIONALLY 20 KT WIND SPEED
ACROSS THE AREA WATERS LATER TONIGHT DUE TO A SLIGHTLY TIGHTENED
SFC PG. HOWEVER...LATEST MODELS INDICATE A BETTER SHOT FOR SCA
CONDITIONS SUNDAY NIGHT INTO MONDAY FROM THE INTERACTION OF AN
APPROACHING SFC COLD FRONT AND THE DISTURBANCE ALOFT MOVING
OVERHEAD. THIS IS BEYOND THE NEAR TERM BUT WORTH MENTIONING.
PREVIOUS DISCUSSION.................................
AS OF 715 PM SATURDAY...LATEST BUOY AND PIER SIGNIFICANT SEAS AND
WINDS OBS FROM WITHIN AND NEARBY LOCATIONS ACROSS THE ILM CWA
INDICATE A RATHER SOLID SSE-SSW WIND AROUND 15 KT WITH SIG. SEAS
ALREADY IN THE 3 TO 4 FT RANGE. A FEW SAMPLED BUOYS AND PIERS
INCLUDE 41108...41110...41036-7 AND 8...MROS1...JMPN7 AND OCPN7.
THE SFC PG IS PROGGED TO EVEN FURTHER TIGHTEN LATER TONIGHT WHICH
MAY REQUIRE AN ADDITIONAL CWF UPDATE LATER THIS EVENING FOR THE
POSSIBLE ISSUANCE OF A SCEC...IE. WINDS SSE-SSW 10-20 KT AND SIG.
SEAS 3 TO 5 FT. WILL CONTINUE TO CLOSELY MONITOR.
PREVIOUS DISCUSSION...........................
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...DCH/III
SHORT TERM...TRA
LONG TERM...RGZ
AVIATION...BJR
AREA FORECAST DISCUSSION...UPDATED
NWS WILMINGTON NC
913 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 /UNTIL 6 AM SUNDAY MORNING/...
AS OF 700 PM SATURDAY...DID NOT THINK THAT THE ILM CWA WOULD BE
NEARLY PCPN-FREE AT THIS TIME. KLTX 88D IS OBS AND TRENDS CONFIRM
THIS CONVECTION FREE TIME FOR THE MOMENT. DETAILED HOURLY MODEL
MODEL DATA HAS SOMEWHAT CAUGHT UP...IE. THE HRRR MODEL...AND IT
SAYS THAT THE REMAINDER OF THIS EVENING LOOKS TO REMAIN PCPN
FREE...ESPECIALLY INLAND. HOWEVER...THE HRRR SEEMS OVERDONE WITH
ONSHORE MOVEMENT OF PCPN THIS EVENING ESPECIALLY WHEN COMPARING
THE LATEST HRRR REFLECTIVITY WITH CURRENT KLTX 88D RADAR DATA.
AS A RESULT...HAVE LOWERED POPS BY UP TO A SEVERAL CATEGORIES FOR
THE REMAINDER OF THIS EVENING. THE HRRR AND ESPECIALLY THE LATEST
NAM CONTINUE WITH INCREASING DEVELOPMENT OF NOCTURNAL ATL
CONVECTION ALONG OUR ADJACENT COASTAL AND OFFSHORE WATERS AFTER
MIDNIGHT...AND THEIR ONSHORE MOVEMENT DURING THE SUNDAY PRE-DAWN
HRS. WILL RAMP POPS BACK UP ACROSS THE FA...MAINLY ACROSS THE
COASTAL COUNTIES WITH A SLOWER INCREASING POP TREND LEADING UP TO
THE I-95 CORRIDOR. HAVE ALSO DECREASED CLOUDINESS ACROSS THE FA
FOR THIS EVENING. HAVE NOT INTRODUCED FOG AT THE MOMENT BUT IF THE
FA EXPERIENCES AN EXTENDED PERIOD OF MOSTLY CLEAR SKIES THIS
EVENING AND/OR OVERNIGHT...FOG MAY BECOME AN ISSUE. HAVE TWEAKED
VERY LITTLE WITH TONIGHTS LOWS...LOOK AOK EVEN WITH A MOSTLY CLEAR
SKIES AT TIMES. TROPICAL AIR MASS REMAINS IN PLACE...WITH SFC
DEWPOINTS REMAINING IN THE LOW TO MID 70S.
PREVIOUS DISCUSSION....................................
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 /6 AM SUNDAY MORNING 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 /01Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...THE RADAR IS QUIET THIS EVENING SO WE CAN EXPECT A LULL
IN PCPN EARLY TONIGHT. A WEAK SFC LOW NEAR THE GA/SC COAST WILL
SLOWLY MOVE NORTHEAST OVERNIGHT...AND THE HRRR INDICATES MORE SHOWER
ACTIVITY WILL SPREAD UP THE COAST AFTER 06Z SUN. THIS COULD RESULT
IN TEMPO MVFR CIGS/VSBYS AT THE COASTAL TERMS EARLY SUN MORNING.
HAVE NOT INCLUDED VCSH FOR KFLO/KLBT AS THE HI-RES GUIDANCE AND SREF
PROBS INDICATE PCPN WILL MAINLY BE CONFINED TO THE COAST. BUT THE
RELATIVE LACK OF CLOUD COVER INLAND COULD RESULT IN IFR CIGS AND/OR
VSBYS AROUND DAYBREAK AT KFLO/KLBT. SINCE CONFIDENCE IS STILL LOW
ATTM...WILL INCLUDE MVFR VSBYS AND SCT 500 FT STRATUS AND REEVALUATE
WITH THE NEXT ISSUANCE. EXPECT WIDESPREAD SHOWERS DURING THE DAY SUN
AS TROPICAL MOISTURE STREAMS ONSHORE AND A COLD FRONT ENTERS OUR
CWA. THERE WILL LIKELY BE SOME MVFR/IFR VSBYS IN LOCALLY HEAVIER
SHOWERS...BUT FOR NOW WILL CARRY 6SM SHRA AND MVFR CIGS FOR ALL
TERMINALS THROUGH THE DAY.
EXTENDED OUTLOOK...SHOWERS WITH PERIODS OF MVFR CIGS AND MVFR/IFR
VSBYS THROUGH MONDAY. VFR TUESDAY THROUGH THURSDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 845 PM SATURDAY...HAVE RAISED A BORDERLINE SCEC FOR ALL
WATERS TONIGHT INTO SUNDAY. LATEST WIND AND SFC OBS ACROSS THE
LOCAL WATERS AS MENTIONED IN THE EARLIER UPDATE...ARE BASICALLY
5 KT AND 1 FOOT AWAY FROM A BORDERLINE SCEC. LATEST HRRR AND NAM
STILL INDICATE A SUSTAINED 15 TO OCCASIONALLY 20 KT WINDSPEED
ACROSS THE AREA WATERS LATER TONIGHT DUE TO A SLIGHTLY TIGHTENED
SFC PG. HOWEVER...LATEST MODELS INDICATE A BETTER SHOT FOR SCA
CONDITIONS SUNDAY NIGHT INTO MONDAY FROM THE INTERACTION OF AN
APPROACHING SFC COLD FRONT AND THE DISTURBANCE ALOFT MOVING
OVERHEAD. THIS IS BEYOND THE NEAR TERM BUT WORTH MENTIONING.
PREVIOUS DISCUSSION...........................................
AS OF 715 PM SATURDAY...LATEST BUOY AND PIER SIGNIFICANT SEAS AND
WINDS OBS FROM WITHIN AND NEARBY LOCATIONS ACROSS THE ILM CWA
INDICATE A RATHER SOLID SSE-SSW WIND AROUND 15 KT WITH SIG. SEAS
ALREADY IN THE 3 TO 4 FT RANGE. A FEW SAMPLED BUOYS AND PIERS
INCLUDE 41108...41110...41036-7 AND 8...MROS1...JMPN7 AND OCPN7.
THE SFC PG IS PROGGED TO EVEN FURTHER TIGHTEN LATER TONIGHT WHICH
MAY REQUIRE AN ADDITIONAL CWF UPDATE LATER THIS EVENING FOR THE
POSSIBLE ISSUANCE OF A SCEC...IE. WINDS SSE-SSW 10-20 KT AND SIG.
SEAS 3 TO 5 FT. WILL CONTINUE TO CLOSELY MONITOR.
PREVIOUS DISCUSSION....................................
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...DCH/III
SHORT TERM...TRA
LONG TERM...RGZ
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
741 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 /UNTIL 6 AM SUNDAY MORNING/...
AS OF 700 PM SATURDAY...DID NOT THINK THAT THE ILM CWA WOULD BE
NEARLY PCPN-FREE AT THIS TIME. KLTX 88D IS OBS AND TRENDS CONFIRM
THIS CONVECTION FREE TIME FOR THE MOMENT. DETAILED HOURLY MODEL
MODEL DATA HAS SOMEWHAT CAUGHT UP...IE. THE HRRR MODEL...AND IT
SAYS THAT THE REMAINDER OF THIS EVENING LOOKS TO REMAIN PCPN
FREE...ESPECIALLY INLAND. HOWEVER...THE HRRR SEEMS OVERDONE WITH
ONSHORE MOVEMENT OF PCPN THIS EVENING ESPECIALLY WHEN COMPARING
THE LATEST HRRR REFLECTIVITY WITH CURRENT KLTX 88D RADAR DATA.
AS A RESULT...HAVE LOWERED POPS BY UP TO A SEVERAL CATEGORIES FOR
THE REMAINDER OF THIS EVENING. THE HRRR AND ESPECIALLY THE LATEST
NAM CONTINUE WITH INCREASING DEVELOPMENT OF NOCTURNAL ATL
CONVECTION ALONG OUR ADJACENT COASTAL AND OFFSHORE WATERS AFTER
MIDNIGHT...AND THEIR ONSHORE MOVEMENT DURING THE SUNDAY PRE-DAWN
HRS. WILL RAMP POPS BACK UP ACROSS THE FA...MAINLY ACROSS THE
COASTAL COUNTIES WITH A SLOWER INCREASING POP TREND LEADING UP TO
THE I-95 CORRIDOR. HAVE ALSO DECREASED CLOUDINESS ACROSS THE FA
FOR THIS EVENING. HAVE NOT INTRODUCED FOG AT THE MOMENT BUT IF THE
FA EXPERIENCES AN EXTENDED PERIOD OF MOSTLY CLEAR SKIES THIS
EVENING AND/OR OVERNIGHT...FOG MAY BECOME AN ISSUE. HAVE TWEAKED
VERY LITTLE WITH TONIGHTS LOWS...LOOK AOK EVEN WITH A MOSTLY CLEAR
SKIES AT TIMES. TROPICAL AIR MASS REMAINS IN PLACE...WITH SFC
DEWPOINTS REMAINING IN THE LOW TO MID 70S.
PREVIOUS DISCUSSION................................................
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 /6 AM SUNDAY MORNING 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 /00Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...THE RADAR IS QUIET THIS EVENING SO WE CAN EXPECT A LULL
IN PCPN EARLY TONIGHT. A WEAK SFC LOW NEAR THE GA/SC COAST WILL
SLOWLY MOVE NORTHEAST OVERNIGHT...AND THE HRRR INDICATES MORE SHOWER
ACTIVITY WILL SPREAD UP THE COAST AFTER 06Z SUN. THIS COULD RESULT
IN TEMPO MVFR CIGS/VSBYS AT THE COASTAL TERMS EARLY SUN MORNING.
HAVE NOT INCLUDED VCSH FOR KFLO/KLBT AS THE HI-RES GUIDANCE AND SREF
PROBS INDICATE PCPN WILL MAINLY BE CONFINED TO THE COAST. BUT THE
RELATIVE LACK OF CLOUD COVER INLAND COULD RESULT IN IFR CIGS AND/OR
VSBYS AROUND DAYBREAK AT KFLO/KLBT. SINCE CONFIDENCE IS STILL LOW
ATTM...WILL INCLUDE MVFR VSBYS AND SCT 500 FT STRATUS AND REEVALUATE
WITH THE NEXT ISSUANCE. EXPECT WIDESPREAD SHOWERS DURING THE DAY SUN
AS TROPICAL MOISTURE STREAMS ONSHORE AND A COLD FRONT ENTERS OUR
CWA. THERE WILL LIKELY BE SOME MVFR/IFR VSBYS IN LOCALLY HEAVIER
SHOWERS...BUT FOR NOW WILL CARRY 6SM SHRA AND MVFR CIGS FOR ALL
TERMINALS THROUGH THE DAY.
EXTENDED OUTLOOK...SHOWERS WITH PERIODS OF MVFR CIGS AND MVFR/IFR
VSBYS THROUGH MONDAY. VFR TUESDAY THROUGH THURSDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 715 PM SATURDAY...LATEST BUOY AND PIER SIGNIFICANT SEAS AND
WINDS OBS FROM WITHIN AND NEARBY LOCATIONS ACROSS THE ILM CWA
INDICATE A RATHER SOLID SSE-SSW WIND AROUND 15 KT WITH SIG. SEAS
ALREADY IN THE 3 TO 4 FT RANGE. A FEW SAMPLED BUOYS AND PIERS
INCLUDE 41108...41110...41036-7 AND 8...MROS1...JMPN7 AND OCPN7.
THE SFC PG IS PROGGED TO EVEN FURTHER TIGHTEN LATER TONIGHT WHICH
MAY REQUIRE AN ADDITIONAL CWF UPDATE LATER THIS EVENING FOR THE
POSSIBLE ISSUANCE OF A SCEC....IE. WINDS SSE-SSW 10-20 KT AND SIG.
SEAS 3 TO 5 FT. WILL CONTINUE TO CLOSELY MONITOR.
PREVIOUS DISCUSSION...............................................
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...DCH/III
SHORT TERM...TRA
LONG TERM...RGZ
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
730 AM EDT FRI SEP 5 2014
.SYNOPSIS...HIGH PRESSURE ALOFT WILL EXTEND ACROSS CENTRAL NC
THROUGH SATURDAY. A COLD FRONT WILL CROSS THE AREA SATURDAY
NIGHT AND STALL TO OUR SOUTH ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM FRIDAY...
THE SUB-TROPICAL RIDGE HOLDS ON ACROSS THE SOUTHEAST US FOR ANOTHER
DAY...AS THE BERMUDA HIGH BUILDS WESTWARD ACROSS THE REGION. THE
WEAK FRONTAL ZONE NEAR THE NC/VA BORDER ON THURSDAY HAS ESSENTIALLY
WASHED OUT...LEAVING MAINLY THE SEABREEZE AND TERRAIN INDUCED
DIFFERENTIAL HEATING AS THE PRIMARY TRIGGERS FOR CONVECTION TODAY.
WHILE NOT A PROMINENT ON RADAR AS WAS THE CASE YESTERDAY...LINGERING
OUTFLOW BOUNDARIES MAY ALSO TRIGGER SOME CONVECTION. THE HRRR SHOWS
SOME LATE MORNING SHOWERS OVER THE NORTHWEST PIEDMONT...WHICH SEEMS
SOMEWHAT REASONABLE GIVEN THAT IT WAS ONE OF THE LAST PLACES TO HAVE
SHOWERS THIS MORNING. MODERATE INSTABILITY OF 1000-2000 J/KG MLCAPE
SHOULD DEVELOP THIS AFTERNOON...BUT WITH VERY WEAK
SHEAR...CONVECTION IS NOT EXPECTED TO BE PARTICULARLY INTENSE.
WILL MOSTLY MAINTAIN THE PREVIOUS FORECAST POPS OF CHANCES IN THE
NORTHWEST AND SOUTHEAST...WITH A SLIGHT CHANCE OVER THE NORTHWEST
PIEDMONT AREA THIS MORNING GIVEN THE REASONING ABOVE. HIGHS AROUND
90 DEGREES.
&&
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
AS OF 320 AM FRIDAY...
SAT AND SAT NIGHT: ONE MORE DAY OF HEAT...IN ADVANCE OF A COLD FRONT
FORECAST TO SETTLE SOUTHEASTWARD TO A POSITION FROM EASTERN NEW
ENGLAND TO THE CENTRAL AND SOUTHERN APPALACHIANS BY SAT EVENING. A
PRE-FRONTAL TROUGH AND THE SEA-BREEZE WILL FOCUS INITIALLY DIURNAL
HEATING-DRIVEN AFTERNOON AND EVENING CONVECTION OVER THE
NORTHWESTERN AND SOUTHERN PORTIONS OF THE RAH CWFA...WITH THE LATTER
POSSIBLY ENHANCED BY THE SLOW NORTHWARD DRIFT OF AN AREA OF
DISTURBED WEATHER FORECAST TO DRIFT NORTH FROM THE EAST COAST OF FL
TO EASTERN GA AND SC. SHOWERS AND STORMS WILL LIKELY PERSIST
THROUGHOUT THE NIGHT...PARTICULARLY NORTH OF THE SANDHILLS AND
SOUTHERN COASTAL PLAIN...AS THE AFOREMENTIONED COLD FRONT OVERTAKES
THE PRE-FRONTAL TROUGH OVER NORTHERN AND CENTRAL NC OVERNIGHT. LOWS
IN THE MIDDLE TO UPPER 60S IN DEVELOPING POST-FRONTAL CAA OVER THE
NORTHERN PIEDMONT...TO LOWER 70S OVER THE WARM SECTOR IN THE
SANDHILLS AND SOUTHERN COASTAL PLAIN.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 340 AM FRIDAY...
SUN: THE COLD FRONT...WHOSE TIMING HAS SLOWED VERSUS THE FASTER
TREND IN NWP GUIDANCE NOTED YESTERDAY...IS NOW FORECAST TO ROUGHLY
BISECT CENTRAL NC FROM NW TO SE AT THE START OF THE DAY SUN...THEN
ONLY SLOWLY DRIFT SOUTHEASTWARD THROUGHOUT THE DAY. THE RESULT WILL
BE NUMEROUS TO WIDESPREAD SHOWERS AND STORMS OVER A LARGER PART OF
THE CWFA...OVER ALL BUT THE FAR NORTHERN AND NW PIEDMONT WHERE POP
WILL BE IN THE CHANCE RANGE...THROUGH THE AFTERNOON. NOT AS
WARM...WITH HIGHS IN THE LOWER 80S NW...TO UPPER 80S TOWARD KFAY-
KGSB-KCTZ. IN AN ENVIRONMENT CHARACTERIZED BY PRECIPITABLE WATER
VALUES NEAR TWO INCHES...FLOODING IN URBAN AND OTHER FLOOD PRONE
AREAS WILL BE POSSIBLE.
SUN NIGHT-MON NIGHT: THE FRONT IS THEN FORECAST TO SLOW AS IT INTO
EASTERN NC (NOT AS FAR EAST AS EARLIER PROGGED). FRONTAL CONVERGENCE
AND INVOF A WAVE OR TWO OF LOW PRESSURE FORECAST TO RIPPLE ALONG THE
FRONT...AND ISENTROPIC UPGLIDE ATOP IT...WILL PROMOTE A LIKELY
PROBABILITY OF SHOWERS AND STORMS THROUGH MON...PARTICULARLY OVER
THE EASTERN PIEDMONT AND COASTAL PLAIN. NORTHEASTERLY FLOW AND
ASSOCIATED MOSTLY CLOUDY CONDITIONS...AND CHANCE OF SHOWERS...WILL
PREVAIL OVER THE SOUTHERN AND WESTERN PIEDMONT. COOLER WITH HIGHS
MOSTLY IN THE 70S...AND LOWS 65 TO 70.
TUE-THU: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE
NORTHEASTERLY FLOW...WITH ASSOCIATED DECREASING CLOUDINESS...AND
MODERATION INTO THE UPPER 70S TO MIDDLE 80S. SHOWER AND STORM
CHANCES...JUST SLIGHT TO LOW CHANCE ONES...SHOULD BE CONFINED TO
EASTERN AREAS TUE...WITH TYPICAL POP DISTRIBUTION INVOF THE SEA
BREEZE AND MOUNTAINS AS CENTRAL NC REMAINS BETWEEN THE DEPARTING SFC
WAVES AND THE NEXT FRONT FORECAST TO ARRIVE LATE NEXT WEEK.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 730 AM FRIDAY...
A FEW AREAS OF LOW STRATUS ARE CURRENTLY IMPACTING KFAY...KRDU AND
KRWI. RECENT OBS SUGGEST THE STRATUS WILL LIFT VERY QUICKLY THIS
MORNING...AND VFR CONDITIONS ARE EXPECTED AREA-WIDE BY 14Z. SHOWERS
AND STORMS ARE POSSIBLE AGAIN THIS AFTERNOON/EVENING...MORE LIKELY
AT KFAY AND KGSO/KINT...THOUGH THE OVERALL COVERAGE IS EXPECTED TO
BE LESS THAN IN THE PAST COUPLE OF DAYS. TONIGHT...WITH HIGH
PRESSURE STILL IN CONTROL AND POTENTIALLY LESS CLOUD COVER THAN IN
PREVIOUS NIGHTS...FOG MAY BE A CONCERN AFTER MIDNIGHT.
OUTLOOK...A COLD FRONT WILL APPROACH THE REGION LATE SATURDAY INTO
SUNDAY...LEADING TO INCREASED CHANCES OF SHOWERS AND THUNDERSTORMS.
THE BEST CHANCES OF CONVECTION WILL SHIFT TOWARDS THE SOUTH AND EAST
BY EARLY NEXT WEEK AS THE FRONT STALLS NEAR THE COAST. LOW
CLOUDS/FOG WILL BE POSSIBLE EACH MORNING...WITH POSSIBLY AN
EXTENDED PERIOD OF SUB VFR CONDITIONS EARLY NEXT WEEK AS HIGH
PRESSURE EXTENDS DOWN INTO THE REGION AND MOIST NORTHEASTERLY FLOW
PREVAILS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...BLS
SHORT TERM...MWS
LONG TERM...MWS
AVIATION...KRD/BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
345 AM EDT FRI SEP 5 2014
.SYNOPSIS...HIGH PRESSURE ALOFT WILL EXTEND ACROSS CENTRAL NC
THROUGH SATURDAY. A COLD FRONT WILL CROSS THE AREA SATURDAY
NIGHT AND STALL TO OUR SOUTH ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM FRIDAY...
THE SUB-TROPICAL RIDGE HOLDS ON ACROSS THE SOUTHEAST US FOR ANOTHER
DAY...AS THE BERMUDA HIGH BUILDS WESTWARD ACROSS THE REGION. THE
WEAK FRONTAL ZONE NEAR THE NC/VA BORDER ON THURSDAY HAS ESSENTIALLY
WASHED OUT...LEAVING MAINLY THE SEABREEZE AND TERRAIN INDUCED
DIFFERENTIAL HEATING AS THE PRIMARY TRIGGERS FOR CONVECTION TODAY.
WHILE NOT A PROMINENT ON RADAR AS WAS THE CASE YESTERDAY...LINGERING
OUTFLOW BOUNDARIES MAY ALSO TRIGGER SOME CONVECTION. THE HRRR SHOWS
SOME LATE MORNING SHOWERS OVER THE NORTHWEST PIEDMONT...WHICH SEEMS
SOMEWHAT REASONABLE GIVEN THAT IT WAS ONE OF THE LAST PLACES TO HAVE
SHOWERS THIS MORNING. MODERATE INSTABILITY OF 1000-2000 J/KG MLCAPE
SHOULD DEVELOP THIS AFTERNOON...BUT WITH VERY WEAK
SHEAR...CONVECTION IS NOT EXPECTED TO BE PARTICULARLY INTENSE.
WILL MOSTLY MAINTAIN THE PREVIOUS FORECAST POPS OF CHANCES IN THE
NORTHWEST AND SOUTHEAST...WITH A SLIGHT CHANCE OVER THE NORTHWEST
PIEDMONT AREA THIS MORNING GIVEN THE REASONING ABOVE. HIGHS AROUND
90 DEGREES.
&&
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
AS OF 320 AM FRIDAY...
SAT AND SAT NIGHT: ONE MORE DAY OF HEAT...IN ADVANCE OF A COLD FRONT
FORECAST TO SETTLE SOUTHEASTWARD TO A POSITION FROM EASTERN NEW
ENGLAND TO THE CENTRAL AND SOUTHERN APPALACHIANS BY SAT EVENING. A
PRE-FRONTAL TROUGH AND THE SEA-BREEZE WILL FOCUS INITIALLY DIURNAL
HEATING-DRIVEN AFTERNOON AND EVENING CONVECTION OVER THE
NORTHWESTERN AND SOUTHERN PORTIONS OF THE RAH CWFA...WITH THE LATTER
POSSIBLY ENHANCED BY THE SLOW NORTHWARD DRIFT OF AN AREA OF
DISTURBED WEATHER FORECAST TO DRIFT NORTH FROM THE EAST COAST OF FL
TO EASTERN GA AND SC. SHOWERS AND STORMS WILL LIKELY PERSIST
THROUGHOUT THE NIGHT...PARTICULARLY NORTH OF THE SANDHILLS AND
SOUTHERN COASTAL PLAIN...AS THE AFOREMENTIONED COLD FRONT OVERTAKES
THE PRE-FRONTAL TROUGH OVER NORTHERN AND CENTRAL NC OVERNIGHT. LOWS
IN THE MIDDLE TO UPPER 60S IN DEVELOPING POST-FRONTAL CAA OVER THE
NORTHERN PIEDMONT...TO LOWER 70S OVER THE WARM SECTOR IN THE
SANDHILLS AND SOUTHERN COASTAL PLAIN.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 340 AM FRIDAY...
SUN: THE COLD FRONT...WHOSE TIMING HAS SLOWED VERSUS THE FASTER
TREND IN NWP GUIDANCE NOTED YESTERDAY...IS NOW FORECAST TO ROUGHLY
BISECT CENTRAL NC FROM NW TO SE AT THE START OF THE DAY SUN...THEN
ONLY SLOWLY DRIFT SOUTHEASTWARD THROUGHOUT THE DAY. THE RESULT WILL
BE NUMEROUS TO WIDESPREAD SHOWERS AND STORMS OVER A LARGER PART OF
THE CWFA...OVER ALL BUT THE FAR NORTHERN AND NW PIEDMONT WHERE POP
WILL BE IN THE CHANCE RANGE...THROUGH THE AFTERNOON. NOT AS
WARM...WITH HIGHS IN THE LOWER 80S NW...TO UPPER 80S TOWARD KFAY-
KGSB-KCTZ. IN AN ENVIRONMENT CHARACTERIZED BY PRECIPITABLE WATER
VALUES NEAR TWO INCHES...FLOODING IN URBAN AND OTHER FLOOD PRONE
AREAS WILL BE POSSIBLE.
SUN NIGHT-MON NIGHT: THE FRONT IS THEN FORECAST TO SLOW AS IT INTO
EASTERN NC (NOT AS FAR EAST AS EARLIER PROGGED). FRONTAL CONVERGENCE
AND INVOF A WAVE OR TWO OF LOW PRESSURE FORECAST TO RIPPLE ALONG THE
FRONT...AND ISENTROPIC UPGLIDE ATOP IT...WILL PROMOTE A LIKELY
PROBABILITY OF SHOWERS AND STORMS THROUGH MON...PARTICULARLY OVER
THE EASTERN PIEDMONT AND COASTAL PLAIN. NORTHEASTERLY FLOW AND
ASSOCIATED MOSTLY CLOUDY CONDITIONS...AND CHANCE OF SHOWERS...WILL
PREVAIL OVER THE SOUTHERN AND WESTERN PIEDMONT. COOLER WITH HIGHS
MOSTLY IN THE 70S...AND LOWS 65 TO 70.
TUE-THU: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE
NORTHEASTERLY FLOW...WITH ASSOCIATED DECREASING CLOUDINESS...AND
MODERATION INTO THE UPPER 70S TO MIDDLE 80S. SHOWER AND STORM
CHANCES...JUST SLIGHT TO LOW CHANCE ONES...SHOULD BE CONFINED TO
EASTERN AREAS TUE...WITH TYPICAL POP DISTRIBUTION INVOF THE SEA
BREEZE AND MOUNTAINS AS CENTRAL NC REMAINS BETWEEN THE DEPARTING SFC
WAVES AND THE NEXT FRONT FORECAST TO ARRIVE LATE NEXT WEEK.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...
EARLY CONVECTION HAD DWINDLED IN THE PAST COUPLE OF HOURS..LEAVING
JUST SOME AREAS OF VERY LIGHT THAT WILL ALSO COME TO AN END.
CONDITIONS HAVE IMPROVED TO VFR ACROSS ALL OF CENTRAL NC...BUT
EXPECT SOME STRATUS TO REDEVELOP BY 09-10Z...ESPECIALLY IN AREAS
THAT RECEIVED MORE SIGNIFICANT RAINFALL LAST EVENING. BASED ON
THIS...CONFIDENCE IN SUB-VFR...LIKELY IFR OR LIFR...CEILINGS IS
GREATEST AT KRDU AND KRWI.
STRATUS WILL DISPERSE AND VFR CONDITIONS ARE EXPECTED AGAIN BY MID-
MORNING. SHOWERS AND STORMS ARE POSSIBLE AGAIN THIS
AFTERNOON/EVENING...MORE LIKELY AT KFAY AND KGSO/KINT...THOUGH THE
OVERALL COVERAGE IS EXPECTED TO BE LESS THAN IN THE PAST COUPLE OF
DAYS.
OUTLOOK...A COLD FRONT WILL APPROACH THE REGION LATE SATURDAY INTO
SUNDAY...LEADING TO INCREASED CHANCES OF SHOWERS AND THUNDERSTORMS.
THE BEST CHANCES OF CONVECTION WILL SHIFT TOWARDS THE SOUTH AND EAST
BY EARLY NEXT WEEK AS THE FRONT STALLS NEAR THE COAST. LOW
CLOUDS/FOG WILL BE POSSIBLE EACH MORNING...WITH POSSIBLY AN
EXTENDED PERIOD OF SUB VFR CONDITIONS EARLY NEXT WEEK AS HIGH
PRESSURE EXTENDS DOWN INTO THE REGION AND MOIST NORTHEASTERLY FLOW
PREVAILS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...BLS
SHORT TERM...MWS
LONG TERM...MWS
AVIATION...KRD/BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
323 AM EDT FRI SEP 5 2014
.SYNOPSIS...HIGH PRESSURE ALOFT WILL EXTEND ACROSS CENTRAL NC
THROUGH SATURDAY. A COLD FRONT WILL CROSS THE AREA SATURDAY
NIGHT AND STALL TO OUR SOUTH ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM FRIDAY...
THE SUB-TROPICAL RIDGE HOLDS ON ACROSS THE SOUTHEAST US FOR ANOTHER
DAY...AS THE BERMUDA HIGH BUILDS WESTWARD ACROSS THE REGION. THE
WEAK FRONTAL ZONE NEAR THE NC/VA BORDER ON THURSDAY HAS ESSENTIALLY
WASHED OUT...LEAVING MAINLY THE SEABREEZE AND TERRAIN INDUCED
DIFFERENTIAL HEATING AS THE PRIMARY TRIGGERS FOR CONVECTION TODAY.
WHILE NOT A PROMINENT ON RADAR AS WAS THE CASE YESTERDAY...LINGERING
OUTFLOW BOUNDARIES MAY ALSO TRIGGER SOME CONVECTION. THE HRRR SHOWS
SOME LATE MORNING SHOWERS OVER THE NORTHWEST PIEDMONT...WHICH SEEMS
SOMEWHAT REASONABLE GIVEN THAT IT WAS ONE OF THE LAST PLACES TO HAVE
SHOWERS THIS MORNING. MODERATE INSTABILITY OF 1000-2000 J/KG MLCAPE
SHOULD DEVELOP THIS AFTERNOON...BUT WITH VERY WEAK
SHEAR...CONVECTION IS NOT EXPECTED TO BE PARTICULARLY INTENSE.
WILL MOSTLY MAINTAIN THE PREVIOUS FORECAST POPS OF CHANCES IN THE
NORTHWEST AND SOUTHEAST...WITH A SLIGHT CHANCE OVER THE NORTHWEST
PIEDMONT AREA THIS MORNING GIVEN THE REASONING ABOVE. HIGHS AROUND
90 DEGREES.
&&
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
AS OF 320 AM FRIDAY...
SAT AND SAT NIGHT: ONE MORE DAY OF HEAT...IN ADVANCE OF A COLD FRONT
FORECAST TO SETTLE SOUTHEASTWARD TO A POSITION FROM EASTERN NEW
ENGLAND TO THE CENTRAL AND SOUTHERN APPALACHIANS BY SAT EVENING. A
PRE-FRONTAL TROUGH AND THE SEA-BREEZE WILL FOCUS INITIALLY DIURNAL
HEATING-DRIVEN AFTERNOON AND EVENING CONVECTION OVER THE
NORTHWESTERN AND SOUTHERN PORTIONS OF THE RAH CWFA...WITH THE LATTER
POSSIBLY ENHANCED BY THE SLOW NORTHWARD DRIFT OF AN AREA OF
DISTURBED WEATHER FORECAST TO DRIFT NORTH FROM THE EAST COAST OF FL
TO EASTERN GA AND SC. SHOWERS AND STORMS WILL LIKELY PERSIST
THROUGHOUT THE NIGHT...PARTICULARLY NORTH OF THE SANDHILLS AND
SOUTHERN COASTAL PLAIN...AS THE AFOREMENTIONED COLD FRONT OVERTAKES
THE PRE-FRONTAL TROUGH OVER NORTHERN AND CENTRAL NC OVERNIGHT. LOWS
IN THE MIDDLE TO UPPER 60S IN DEVELOPING POST-FRONTAL CAA OVER THE
NORTHERN PIEDMONT...TO LOWER 70S OVER THE WARM SECTOR IN THE
SANDHILLS AND SOUTHERN COASTAL PLAIN.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 325 PM THURSDAY...
SATURDAY THROUGH SUNDAY: THE SUB-TROPICAL MID LEVEL RIDGE IS
EXPECTED TO BE SUPPRESSED SOUTH/EASTWARD THIS WEEKEND AS A PAIR OF
S/W DISTURBANCE TRACKING NEAR THE US./CANADIAN BORDER HELP A
MID/UPPER LEVEL TROUGH PUSH EASTWARD ACROSS THE COUNTRY AND AMPLIFY
THE APPROACHING L/W TROUGH. THIS WILL SEND AN ASSOCIATED PRE-FRONTAL
TROUGH AND EVENTUALLY COLD FRONT INTO CENTRAL NC VERY LATE SATURDAY
INTO SUNDAY. WITH A WARM MOIST AIRMASS CHARACTERIZED BY PW`S OF
AROUND 2 INCHES IN ADVANCE OF THIS SYSTEM COUPLED WITH IMPROVING
UPPER DIVERGENCE EXPECT WE SHOULD HAVE A GOOD CHANCE FOR SHOWERS AND
STORMS DURING THIS TIME FRAME. THE BEST CHANCE FOR SATURDAY THOUGH
LOOKS TO BE LATE IN THE DAY... AND BEST CHANCES ACROSS THE NORTHWEST
PIEDMONT AND POSSIBLY ALONG THE SEABREEZE ACROSS OUR SOUTHEASTERN
COUNTIES... THEN TRANSLATING SOUTH AND EASTWARD SATURDAY NIGHT INTO
SUNDAY MORNING. A 1022-1025 MB SURFACE HIGH IS EXPECTED TO BUILD
SOUTHWARD ON SUNDAY INTO SUNDAY NIGHT FROM THE NORTH. THE BEST
CHANCE FOR SHOWERS AND STORMS BY SUNDAY AFTERNOON IS EXPECTED ACROSS
THE SOUTHERN HALF OF THE AREA. WRT A SEVERE THREAT.. SURFACE BASED
CAPE VALUES ON SATURDAY ARE EXPECTED TO BE AROUND 1000-1500 J/KG...
WITH AFTERNOON SBCAPE VALUES BEST ACROSS THE FAR SOUTH ON SUNDAY OF
AROUND 1000-2000 J/KG (AS THE FRONT LOOKS TO BE PUSHING SOUTHWARD
THROUGH THE SOUTHERN HALF OF THE AREA ON SUNDAY AFTERNOON).
HOWEVER... DEEP LAYER SHEAR CONTINUES TO LOOK MARGINAL... GENERALLY
20 KTS OR LESS IN THE WARM SECTOR. THUS... THINK ANY SEVERE THREAT
WILL REMAIN QUITE ISOLATED THIS WEEKEND. HOWEVER... GIVEN THE RATHER
LIGHT STEERING FLOW AND PW`S OF AROUND 2" WE COULD SEE SOME LOCALLY
HEAVY RAIN. PRECIP WILL LIKELY CONTINUE TO LINGER ACROSS SOME IF NOT
MOST OF THE AREA ON SUNDAY NIGHT WITH A MOIST EASTERLY LOW LEVEL
FLOW... TO EAST-SOUTHEAST TO SOUTHEAST AT H85 ATOP THE COOL DOME.
HIGH TEMPS ON SATURDAY IN ADVANCE OF THE COLD FRONT ARE EXPECTED TO
GENERALLY BE AROUND 90/LOWER 90S. SUNDAY... HIGHS WILL BE TRICKY AND
DEPEND ON HOW QUICKLY THE COOLER DRY AIR FILTERS INTO THE AREA AND
HOW MUCH PRECIP WE WILL HAVE BEHIND THE FRONT. FOR NOW WILL GO WITH
HIGH TEMPS AROUND 80 NW TO THE MID TO UPPER 80S FAR SOUTH. LOWS
TEMPS SUNDAY MORNING ARE EXPECTED TO BE IN THE UPPER 60S TO LOWER
70S.. LOWS MONDAY MORNING... WITH POSSIBLY SOME LINGERING SHOWERS...
ARE EXPECTED TO BE IN THE MID 60S NORTH TO MID TO UPPER 60S SOUTH.
MONDAY THROUGH THURSDAY: THE SURFACE FRONT IS EXPECTED TO STALL AS
IT MOVES OFFSHORE AND ENCOUNTERS THE GULF STREAM/OR ALONG THE
COAST... WITH THE POTENTIAL FOR AN AREA OF LOW PRESSURE OR TWO TO
LIFT NORTHWARD ALONG THE FRONT MONDAY INTO TUESDAY. THIS WILL LEAD
TO CONTINUED LINGERING CHANCE OF SHOWERS/RAIN ACROSS THE AREA...
BEST CHANCE EAST. WITH A 1025 MB SURFACE HIGH CONTINUING TO EXTEND
INTO OUR AREA FROM THE NORTHEAST WE SHOULD SEE A COLD AIR DAMMING
AIR MASS ACROSS PORTIONS... IF NOT ALL... OF THE CWA ON MONDAY INTO
TUESDAY. HOWEVER.... THE STRENGTH AND OVERALL EVOLUTION OF THE CAD
WILL HELP DRY THE TEMPS ON MONDAY AND TUESDAY. FOR NOW WILL CONTINUE
TO TREND TEMPS TOWARDS THE COOLER SIDE FOR HIGHS. MID 70S NW TO
AROUND 80 SE FOR MONDAY (POSSIBLY TOO WARM)... WITH UPPER 70S TO
LOWER 80S ON TUESDAY AS SOME DRIER AIR ALOFT MAY BEGIN TO WORK INTO
THE AREA BY THEN.
A SLOW MODERATION WILL CONTINUE ON WEDNESDAY AND THURSDAY... AS ANY
SURFACE LOWS LIFT OFF TO THE NORTHEAST... ALONG WITH BRIEF S/W
RIDING BUILDING ACROSS THE AREA. MEDIUM RANGE MODELS DIFFER ON THE
TIMING OF THE NEXT SYSTEM AND PRECIP CHANCES BY THE END OF THE
PERIOD... THUS... WILL LIMIT POPS TO SLIGHT CHANCE BY WEDNESDAY AND
THURSDAY. HIGHS LOWER TO MID 80S... LOWS MID TO UPPER 60S AT LEAST.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...
EARLY CONVECTION HAD DWINDLED IN THE PAST COUPLE OF HOURS..LEAVING
JUST SOME AREAS OF VERY LIGHT THAT WILL ALSO COME TO AN END.
CONDITIONS HAVE IMPROVED TO VFR ACROSS ALL OF CENTRAL NC...BUT
EXPECT SOME STRATUS TO REDEVELOP BY 09-10Z...ESPECIALLY IN AREAS
THAT RECEIVED MORE SIGNIFICANT RAINFALL LAST EVENING. BASED ON
THIS...CONFIDENCE IN SUB-VFR...LIKELY IFR OR LIFR...CEILINGS IS
GREATEST AT KRDU AND KRWI.
STRATUS WILL DISPERSE AND VFR CONDITIONS ARE EXPECTED AGAIN BY MID-
MORNING. SHOWERS AND STORMS ARE POSSIBLE AGAIN THIS
AFTERNOON/EVENING...MORE LIKELY AT KFAY AND KGSO/KINT...THOUGH THE
OVERALL COVERAGE IS EXPECTED TO BE LESS THAN IN THE PAST COUPLE OF
DAYS.
OUTLOOK...A COLD FRONT WILL APPROACH THE REGION LATE SATURDAY INTO
SUNDAY...LEADING TO INCREASED CHANCES OF SHOWERS AND THUNDERSTORMS.
THE BEST CHANCES OF CONVECTION WILL SHIFT TOWARDS THE SOUTH AND EAST
BY EARLY NEXT WEEK AS THE FRONT STALLS NEAR THE COAST. LOW
CLOUDS/FOG WILL BE POSSIBLE EACH MORNING...WITH POSSIBLY AN
EXTENDED PERIOD OF SUB VFR CONDITIONS EARLY NEXT WEEK AS HIGH
PRESSURE EXTENDS DOWN INTO THE REGION AND MOIST NORTHEASTERLY FLOW
PREVAILS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...BLS
SHORT TERM...MWS
LONG TERM...BSD
AVIATION...KRD/BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
315 AM EDT FRI SEP 5 2014
.SYNOPSIS...HIGH PRESSURE ALOFT WILL EXTEND ACROSS CENTRAL NC
THROUGH SATURDAY. A COLD FRONT WILL CROSS THE AREA SATURDAY
NIGHT AND STALL TO OUR SOUTH ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM FRIDAY...
THE SUB-TROPICAL RIDGE HOLDS ON ACROSS THE SOUTHEAST US FOR ANOTHER
DAY...AS THE BERMUDA HIGH BUILDS WESTWARD ACROSS THE REGION. THE
WEAK FRONTAL ZONE NEAR THE NC/VA BORDER ON THURSDAY HAS ESSENTIALLY
WASHED OUT...LEAVING MAINLY THE SEABREEZE AND TERRAIN INDUCED
DIFFERENTIAL HEATING AS THE PRIMARY TRIGGERS FOR CONVECTION TODAY.
WHILE NOT A PROMINENT ON RADAR AS WAS THE CASE YESTERDAY...LINGERING
OUTFLOW BOUNDARIES MAY ALSO TRIGGER SOME CONVECTION. THE HRRR SHOWS
SOME LATE MORNING SHOWERS OVER THE NORTHWEST PIEDMONT...WHICH SEEMS
SOMEWHAT REASONABLE GIVEN THAT IT WAS ONE OF THE LAST PLACES TO HAVE
SHOWERS THIS MORNING. MODERATE INSTABILITY OF 1000-2000 J/KG MLCAPE
SHOULD DEVELOP THIS AFTERNOON...BUT WITH VERY WEAK
SHEAR...CONVECTION IS NOT EXPECTED TO BE PARTICULARLY INTENSE.
WILL MOSTLY MAINTAIN THE PREVIOUS FORECAST POPS OF CHANCES IN THE
NORTHWEST AND SOUTHEAST...WITH A SLIGHT CHANCE OVER THE NORTHWEST
PIEDMONT AREA THIS MORNING GIVEN THE REASONING ABOVE. HIGHS AROUND
90 DEGREES.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 325 PM THURSDAY...
MID-LEVEL SHEAR AXIS WILL BE EDGES NWD FRIDAY AS BERMUDA HIGH
TEMPORARILY RE-EXERTS ITSELF ACROSS THE CAROLINAS. MODEST HEIGHT
RISES AND ASSOCIATED MID LEVEL SUBSIDENCE INVERSION SHOULD HELP TO
LIMIT CONVECTION INITIATION. THUS CONVECTION WILL BE MORE
SPARSE/ISOLATED COMPARED TOT HE PAST FEW DAYS. AREAS OF EARLY
MORNING LOW CLOUDS/FOG WILL GIVE WAY TO PARTLY SUNNY-MOSTLY SUNNY
SKIES BY MID DAY. THIS HEATING SHOULD BOOST AFTERNOON TEMPS NEAR 90-
LOWER 90S.
CONVECTION WILL DIMINISH SHORTLY AFTER SUNSET. SIMILAR TO THE PAST
FEW NIGHTS....EXPECT AREAS OF LOW CLOUDS AND/OR FOG TO DEVELOP AFTER
MIDNIGHT. MIN TEMPS 68-73.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 325 PM THURSDAY...
SATURDAY THROUGH SUNDAY: THE SUB-TROPICAL MID LEVEL RIDGE IS
EXPECTED TO BE SUPPRESSED SOUTH/EASTWARD THIS WEEKEND AS A PAIR OF
S/W DISTURBANCE TRACKING NEAR THE US./CANADIAN BORDER HELP A
MID/UPPER LEVEL TROUGH PUSH EASTWARD ACROSS THE COUNTRY AND AMPLIFY
THE APPROACHING L/W TROUGH. THIS WILL SEND AN ASSOCIATED PRE-FRONTAL
TROUGH AND EVENTUALLY COLD FRONT INTO CENTRAL NC VERY LATE SATURDAY
INTO SUNDAY. WITH A WARM MOIST AIRMASS CHARACTERIZED BY PW`S OF
AROUND 2 INCHES IN ADVANCE OF THIS SYSTEM COUPLED WITH IMPROVING
UPPER DIVERGENCE EXPECT WE SHOULD HAVE A GOOD CHANCE FOR SHOWERS AND
STORMS DURING THIS TIME FRAME. THE BEST CHANCE FOR SATURDAY THOUGH
LOOKS TO BE LATE IN THE DAY... AND BEST CHANCES ACROSS THE NORTHWEST
PIEDMONT AND POSSIBLY ALONG THE SEABREEZE ACROSS OUR SOUTHEASTERN
COUNTIES... THEN TRANSLATING SOUTH AND EASTWARD SATURDAY NIGHT INTO
SUNDAY MORNING. A 1022-1025 MB SURFACE HIGH IS EXPECTED TO BUILD
SOUTHWARD ON SUNDAY INTO SUNDAY NIGHT FROM THE NORTH. THE BEST
CHANCE FOR SHOWERS AND STORMS BY SUNDAY AFTERNOON IS EXPECTED ACROSS
THE SOUTHERN HALF OF THE AREA. WRT A SEVERE THREAT.. SURFACE BASED
CAPE VALUES ON SATURDAY ARE EXPECTED TO BE AROUND 1000-1500 J/KG...
WITH AFTERNOON SBCAPE VALUES BEST ACROSS THE FAR SOUTH ON SUNDAY OF
AROUND 1000-2000 J/KG (AS THE FRONT LOOKS TO BE PUSHING SOUTHWARD
THROUGH THE SOUTHERN HALF OF THE AREA ON SUNDAY AFTERNOON).
HOWEVER... DEEP LAYER SHEAR CONTINUES TO LOOK MARGINAL... GENERALLY
20 KTS OR LESS IN THE WARM SECTOR. THUS... THINK ANY SEVERE THREAT
WILL REMAIN QUITE ISOLATED THIS WEEKEND. HOWEVER... GIVEN THE RATHER
LIGHT STEERING FLOW AND PW`S OF AROUND 2" WE COULD SEE SOME LOCALLY
HEAVY RAIN. PRECIP WILL LIKELY CONTINUE TO LINGER ACROSS SOME IF NOT
MOST OF THE AREA ON SUNDAY NIGHT WITH A MOIST EASTERLY LOW LEVEL
FLOW... TO EAST-SOUTHEAST TO SOUTHEAST AT H85 ATOP THE COOL DOME.
HIGH TEMPS ON SATURDAY IN ADVANCE OF THE COLD FRONT ARE EXPECTED TO
GENERALLY BE AROUND 90/LOWER 90S. SUNDAY... HIGHS WILL BE TRICKY AND
DEPEND ON HOW QUICKLY THE COOLER DRY AIR FILTERS INTO THE AREA AND
HOW MUCH PRECIP WE WILL HAVE BEHIND THE FRONT. FOR NOW WILL GO WITH
HIGH TEMPS AROUND 80 NW TO THE MID TO UPPER 80S FAR SOUTH. LOWS
TEMPS SUNDAY MORNING ARE EXPECTED TO BE IN THE UPPER 60S TO LOWER
70S.. LOWS MONDAY MORNING... WITH POSSIBLY SOME LINGERING SHOWERS...
ARE EXPECTED TO BE IN THE MID 60S NORTH TO MID TO UPPER 60S SOUTH.
MONDAY THROUGH THURSDAY: THE SURFACE FRONT IS EXPECTED TO STALL AS
IT MOVES OFFSHORE AND ENCOUNTERS THE GULF STREAM/OR ALONG THE
COAST... WITH THE POTENTIAL FOR AN AREA OF LOW PRESSURE OR TWO TO
LIFT NORTHWARD ALONG THE FRONT MONDAY INTO TUESDAY. THIS WILL LEAD
TO CONTINUED LINGERING CHANCE OF SHOWERS/RAIN ACROSS THE AREA...
BEST CHANCE EAST. WITH A 1025 MB SURFACE HIGH CONTINUING TO EXTEND
INTO OUR AREA FROM THE NORTHEAST WE SHOULD SEE A COLD AIR DAMMING
AIR MASS ACROSS PORTIONS... IF NOT ALL... OF THE CWA ON MONDAY INTO
TUESDAY. HOWEVER.... THE STRENGTH AND OVERALL EVOLUTION OF THE CAD
WILL HELP DRY THE TEMPS ON MONDAY AND TUESDAY. FOR NOW WILL CONTINUE
TO TREND TEMPS TOWARDS THE COOLER SIDE FOR HIGHS. MID 70S NW TO
AROUND 80 SE FOR MONDAY (POSSIBLY TOO WARM)... WITH UPPER 70S TO
LOWER 80S ON TUESDAY AS SOME DRIER AIR ALOFT MAY BEGIN TO WORK INTO
THE AREA BY THEN.
A SLOW MODERATION WILL CONTINUE ON WEDNESDAY AND THURSDAY... AS ANY
SURFACE LOWS LIFT OFF TO THE NORTHEAST... ALONG WITH BRIEF S/W
RIDING BUILDING ACROSS THE AREA. MEDIUM RANGE MODELS DIFFER ON THE
TIMING OF THE NEXT SYSTEM AND PRECIP CHANCES BY THE END OF THE
PERIOD... THUS... WILL LIMIT POPS TO SLIGHT CHANCE BY WEDNESDAY AND
THURSDAY. HIGHS LOWER TO MID 80S... LOWS MID TO UPPER 60S AT LEAST.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...
EARLY CONVECTION HAD DWINDLED IN THE PAST COUPLE OF HOURS..LEAVING
JUST SOME AREAS OF VERY LIGHT THAT WILL ALSO COME TO AN END.
CONDITIONS HAVE IMPROVED TO VFR ACROSS ALL OF CENTRAL NC...BUT
EXPECT SOME STRATUS TO REDEVELOP BY 09-10Z...ESPECIALLY IN AREAS
THAT RECEIVED MORE SIGNIFICANT RAINFALL LAST EVENING. BASED ON
THIS...CONFIDENCE IN SUB-VFR...LIKELY IFR OR LIFR...CEILINGS IS
GREATEST AT KRDU AND KRWI.
STRATUS WILL DISPERSE AND VFR CONDITIONS ARE EXPECTED AGAIN BY MID-
MORNING. SHOWERS AND STORMS ARE POSSIBLE AGAIN THIS
AFTERNOON/EVENING...MORE LIKELY AT KFAY AND KGSO/KINT...THOUGH THE
OVERALL COVERAGE IS EXPECTED TO BE LESS THAN IN THE PAST COUPLE OF
DAYS.
OUTLOOK...A COLD FRONT WILL APPROACH THE REGION LATE SATURDAY INTO
SUNDAY...LEADING TO INCREASED CHANCES OF SHOWERS AND THUNDERSTORMS.
THE BEST CHANCES OF CONVECTION WILL SHIFT TOWARDS THE SOUTH AND EAST
BY EARLY NEXT WEEK AS THE FRONT STALLS NEAR THE COAST. LOW
CLOUDS/FOG WILL BE POSSIBLE EACH MORNING...WITH POSSIBLY AN
EXTENDED PERIOD OF SUB VFR CONDITIONS EARLY NEXT WEEK AS HIGH
PRESSURE EXTENDS DOWN INTO THE REGION AND MOIST NORTHEASTERLY FLOW
PREVAILS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...BLS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...KRD/BLS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
146 AM EDT FRI SEP 5 2014
.SYNOPSIS...
SUMMERTIME WEATHER WILL CONTINUE INTO THE WEEKEND. AN APPROACHING
COLD FRONT WILL BRING AN INCREASED RISK OF THUNDERSTORMS LATE IN THE
WEEKEND AND EARLY NEXT WEEK. A STRONGER COLD FRONT MAY APPROACH THE
AREA BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 1045 PM THURSDAY...PCPN TREND FROM THE PREVIOUS UPDATE
STILL HOLDS. HAVE TEMPORARILY ENDED PCPN OVER LAND AREAS ACROSS
THE ILM CWA. BUT WILL CONTINUE THE INCREASING DEVELOPMENT OF
NOCTURNAL SHRA/TSRA ACROSS THE ADJACENT ATL WATERS DURING THE PRE-
DAWN FRI HRS VIA LATEST HRRR MODEL OUTPUT. THE EVENTUAL ONSHORE
MOVEMENT OF THIS PCPN WILL OCCUR TOWARD DAYBREAK FRI...AND THUS
WILL MAINTAIN ATLEAST A 20 POP FOR THE COASTAL COUNTIES AND EXTEND
FURTHER INLAND AFTER SUNRISE FRI. NO TWEAKS TO OVERNITE TEMPS/DEWPTS
AT THIS TIME.
PREVIOUS DISCUSSION.............................................
AS OF 715 PM THURSDAY...LATEST KLTX 88D AND SURROUNDING 88DS
INDICATE THE DIURNALLY DRIVEN CONVECTION HAS ENDED ACROSS THE ILM
CWA. AS A RESULT...HAVE REMOVED POPS FOR THE REMAINDER OF THIS
EVENING AND INTO THE PRE-DAWN FRI HRS. IN ADDITION HAVE DECREASED
CLOUD COVERAGE GIVEN LATEST SAT IMAGERY...AND WITH CONVECTIVE
DEBRIS CLOUDS REMAINING WELL UPSTREAM. HOWEVER...HAVE RAMPED UP THE
NOCTURNAL SHRA/TSRA POP ALONG THE COASTAL COUNTIES FROM PCPN MOVING
ONSHORE FROM OFF THE ATL OCEAN TO ATLEAST 20...AND POSSIBLY UP TO 30
LEADING UP TO FRI SUNRISE AND IMMEDIATELY THERE-AFTER. VARIOUS MODEL
TIME HEIGHT DISPLAYS ACROSS COASTAL NC-SC INDICATE A MUCH DEEPER
ONSHORE FLOW...IE. SE-SSW FLOW UP TO 5H...ACROSS COASTAL NC-SC...AND
ALSO ALONG WITH PLENTY OF LOW-LEVEL MOISTURE AFTER MIDNIGHT
FRI...EXTENDING FROM THE SFC UP THRU 8H. ONSHORE FLOW HAVING CROSSED
SSTS AROUND 80 DEGREES...WILL KEEP TONIGHTS LOWS IN THE MID AND
UPPER 70S AT THE COAST. LOWER 70S LIKELY FAR WEST PORTIONS...MAINLY
ALONG AND WEST OF THE I-95 CORRIDOR.
PREVIOUS DISCUSSION..................................
AS OF 130 PM THURSDAY...FORECAST FOR THE AFTERNOON AND OVERNIGHT
HOURS REMAINS RELATIVELY UNCHANGED. ALL WE HAVE SEEN SO FAR IS
VERY SHALLOW TROPICAL SHOWERS AND THE CUMULUS FIELD LOOKS LIKE
THIS CWA WIDE SO THE CHANCE OF DEEP CONVECTION IS DIMINISHING.
STILL CANT RULE OUT SOME DEEPER ACTIVITY ACROSS NORTHWESTERN AREAS
AND WILL ADJUST POPS ACCORDINGLY IF NECESSARY. WILL MAINTAIN THE
LOW CHANCE POPS FOR THE AFTERNOON HOURS AND FOR THE ACTIVITY
EXPECTED TO DEVELOP ACROSS THE ATLANTIC OVERNIGHT. OVERNIGHT LOWS
REMAIN STEAMY AND OPTED FOR THE WARMER GUIDANCE WHICH HAS BEEN A
GOOD PLAY RECENTLY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...HAVE FAVORED THE SLOWER GFS SOLUTION FOR
THIS PERIOD OVER THE MORE PROGRESSIVE NAM. HIGH PRESSURE CONTINUES
ACROSS THE SOUTHEAST AS THE DOMINATE WEATHER MAKER...WEAK SURFACE
FLOW WILL ALLOW SEA BREEZE TO PUSH INLAND AND THIS WILL SERVE AS
THE MAIN TRIGGER ELEMENT FOR ANY SHOWERS OR STORMS THAT DEVELOP
THROUGHOUT THE AFTERNOON. HAVE FAVORED THE LOWER CHANCE POPS OF
THE GFS AS NAM RAMPS UP POPS I THINK TOO QUICKLY BY LATE DAY IN THE
ABSENCE OF ANY UPPER LEVEL DISTURBANCE THAT REMAINS WELL TO THE
WEST OF THE CWA BY FRIDAY LATE AFTERNOON. APPROACHING FRONTAL
BOUNDARY WILL REMAIN WELL TO OUR WEST AND NORTHWEST FRIDAY. WITH
LESS CLOUD COVER ON THE GFS THAN NAM FAVORED THE HIGHER GFS TEMPS
OF UPPER 80S TO AROUND 90 INLAND WITH H8 TEMPS AROUND 18C WITH A
WEAK LESS THAN 10 KT SOUTHERLY H8 FLOW INCREASING MOISTURE INTO
THE REGION. ON SATURDAY I START TO RAMP UP THE POPS BY THE END OF
THE PERIOD AS COMBINATION OF INCREASED SOUTHERLY H8 SPEED
CONVERGENCE INTERACTS WITH SEA BREEZE FRONT TO IGNITE MORE
SCATTERED SHOWERS AND STORMS ESPECIALLY LATER IN THE AFTERNOON.
WEAK H5 DISTURBANCE MOVES INTO THE WESTERN PORTION OF THE STATE
AND SHOULD ENHANCE THE PIEDMONT TROUGH CONVECTION DURING SATURDAY
EVENING SO WILL UP THE POPS HERE LATE IN THE PERIOD. WITH A JUICY
ATMOSPHERE ANY SHOWERS OR STORMS WILL HAVE THE POTENTIAL TO
PRODUCE SOME LOCALLY HEAVY RAINS ESPECIALLY INLAND AS THE STEERING
WINDS WILL BE LIGHTER COMPARED TO NEAR THE COAST WHERE THE LOW
LEVEL JET SHOULD HAVE A 190 DIRECTION AT AROUND 15 KNOTS WHICH
SHOULD HELP IN KEEPING ANY PROLONG PERIOD OF RAIN OVER ANY AREA.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...THE SUBTROPICAL RIDGE WILL REMAIN TO OUR
SOUTH NEXT WEEK WITH THE SOUTHERN EDGE OF THE MID-LATITUDE
WESTERLIES BRUSHING THE CAROLINAS. MODELS SHOW THE BEST POTENTIAL
FOR DEEP MOISTURE AND CYCLONIC CURVATURE TO THE 500 MB FLOW WILL
BE SUNDAY/MONDAY...COINCIDENT WITH THE ARRIVAL OF A COLD FRONT
PUSHED SOUTHWARD INTO THE CAROLINAS BY SURFACE HIGH PRESSURE OVER
THE UPPER MIDWEST. AS WEAK LOW PRESSURE DEVELOPS ALONG THE STALLED
FRONT OVER SOUTHERN SOUTH CAROLINA/EASTERN GEORGIA MONDAY...MOIST
SOUTHEAST WINDS WILL ADVECT PLENTY OF ATLANTIC MOISTURE ONSHORE
ACROSS THE AREA. THIS COULD LEAD TO FAIRLY WIDESPREAD SHOWERS AND
T-STORMS. I HAVE INCREASED FORECAST POPS TO 50-70 PERCENT SUNDAY
AND MONDAY.
ONE INTERESTING FEATURE THAT WILL HAVE TO BE WATCHED CLOSELY IS
LOCATED OFF THE FLORIDA EAST COAST THIS AFTERNOON. MODELS SHOW SOME
OF THE DEEP TROPICAL MOISTURE TRAILING BEHIND THIS CYCLONIC SWIRL
COULD BE INGESTED INTO THE SUNDAY/MONDAY WEATHER SYSTEM. WHILE THIS
NOT GOING TO BE A TROPICAL SYSTEM PER SE...ADVECTING TROPICAL
MOISTURE ACROSS A SYNOPTIC COLD FRONT CAN LEAD TO SIGNIFICANT AND
PERHAPS EXCESSIVE RAINFALL.
THE WEAK SURFACE LOW SHOULD LIFT OUT TO THE NORTHEAST TUESDAY WITH
RAINFALL CHANCES DIMINISHING THROUGH MID-WEEK. THE AIRMASS WILL
REMAIN TROPICAL AND MAINLY DIURNAL 20-30 POPS WILL REMAIN IN THE
FORECAST.
HIGH TEMPERATURES WILL REMAIN BELOW CLIMATOLOGICAL NORMS MONDAY AND
TUESDAY DUE TO THE CLOUDS AND PRECIP ANTICIPATED WITH THE FRONT
STALLING NEAR THE AREA. ONCE THIS FEATURE IS GONE TUESDAY HIGH
TEMPERATURES SHOULD REMAIN TO NEAR OR EVEN SLIGHTLY ABOVE NORMALS
FOR THE REST OF THE WEEK.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...POTENTIAL FOR MVFR/IFR DUE TO FOG OVERNIGHT INTO THE
EARLY MORNING HOURS. OTHERWISE EXPECT VFR WITH A CHANCE OF AFTERNOON
SHRA/TSRA ON THURSDAY.
LIGHT WINDS AND VFR PREVAILS THIS EVENING. THERE IS THE POTENTIAL
FOR MVFR/POSSIBLE IFR DUE TO AREAS OF FOG/LOW CIGS AT THE INLAND
SITES AROUND DAYBREAK. DO NOT ANTICIPATE ANY OF THIS TO DEVELOP
ALONG THE COAST...BUT COULD SEE SOME ISOLATED SHOWER ACTIVITY MOVE
ASHORE. AFTER SUNRISE...VFR WILL PREVAIL WITH SOUTH-SOUTHEAST WINDS
AROUND 5 TO 10 KT...SLIGHTLY HIGHER ALONG THE COAST...WITH A
CHANCE OF SHRA/TSRA. INTO THE EVENING HOURS...WINDS WILL DECREASE
AND ANY SHRA/TSRA ACTIVITY WILL TAPER OFF.
EXTENDED OUTLOOK...PATCHY MVFR/IFR FOG OR STRATUS MAY DEVELOP EACH
MORNING. A COLD FRONT WILL DROP INTO THE REGION SUNDAY AND MONDAY...
WITH A HIGHER RISK FOR SHOWERS AND STORMS BOTH DAYS. THE FRONT
STALLS WITH A CONTINUED CHANCE FOR SHOWERS TUESDAY.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 1100 PM THURSDAY...NEARLY A PCPN FREE COASTAL AND
ADJACENT OFFSHORE WATERS AT THE MOMENT...VIA LATEST KLTX 88D
AND SURROUNDING RADARS. STILL BANKING ON THE LATEST HRRR WHICH
INDICATES PCPN RE-FIRING DURING THE PRE-DAWN FRI HRS. NO POP
CHANGES NEEDED AT THIS TIME. LATEST BUOYS OBS ACROSS AND IN THE
NEIGHBORHOOD OF THE ILM COASTAL WATERS CONTINUE TO SUPPORT THE
PREVIOUS UPDATE WITH VERY LITTLE TWEAKING...IF ANY...NEEDED TO
EITHER WINDS/SEAS IN THIS UPDATE.
PREVIOUS DISCUSSION..............................................
AS OF 730 PM THURSDAY...LATEST PROGGED SFC PRESSURE PATTERN AND
RELAXED GRADIENT ACROSS THE ILM WATERS OVERNIGHT TO YIELD A SE-S
WIND AT 10 TO 15 KT...WITH THE 15 KT BEING VERY GENEROUS.
SIGNIFICANT SEAS WILL REMAIN IN A 2 TO 3 FOOT RANGE...WITH THE
DOMINANT PLAYER WITH THE SIG. SEAS BEING A LAZY 2 FOOT ESE GROUND
SWELL EXHIBITING 8 SECOND PERIODS. THE REMAINDER OF THE SIG. SEAS
PRODUCTION WILL COME FROM A 1-2 FOOT LOCALLY PRODUCED WIND WAVE AT
4-5 SECOND PERIODS. NOCTURNAL SHRA/TSRA WILL INCREASE IN COVERAGE
ACROSS THE LOCAL WATERS DURING THE MID TO LATE PRE-DAWN FRI HRS.
PREVIOUS DISCUSSION...........................................
AS OF 130 PM THURSDAY...MUCH LIKE THE PUBLIC PART OF THE
FORECAST...THE COASTAL WATERS FORECAST REMAINS STABLE. SOUTH WINDS
HOVERING AROUND TEN KNOTS WILL CONTINUE. SIGNIFICANT SEAS WILL BE
1-3 FEET WITH MOSTLY LOCAL WIND DRIVEN WAVES WITH PERIODS OF SIX
TO EIGHT SECONDS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...HIGH PRESSURE WILL COVER THE COASTAL
WATERS THROUGHOUT THE PERIOD. WINDS WILL GENERALLY BE LIGHT
ACROSS THE WATERS FROM THE S TO SE BUT SHOULD START TO INCREASE BY
AFTERNOON AND EVENING ON SATURDAY AS H8 WINDS DEVELOP THE LOW
LEVEL JET. SEAS WILL GENERALLY RUN AROUND A FOOT OR SO NEAR SHORE
AND 2-3 OFFSHORE. EXPECT SOME SCATTERED SHOWERS STORMS EACH DAY
WITH CONDITIONS STARTING TO DETERIORATE MORE BY THE END OF THE
PERIOD AS A COLD FRONT APPROACHES FROM THE WEST AND LOW PRESSURE
IS FORECAST TO DEVELOP ALONG THIS FRONT FOR THE LONG TERM PERIOD.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 300 PM THURSDAY...1022 MB HIGH PRESSURE OVER THE UPPER
MIDWEST SUNDAY WILL PUSH A COLD FRONT SOUTHWARD ACROSS THE MID-
ATLANTIC REGION. THIS FRONT SHOULD REACH THE INLAND CAROLINAS
DURING THE DAY SUNDAY BUT WILL HAVE TROUBLE PUSHING OUT ACROSS THE
COASTAL WATERS. THE LATEST SUITE OF COMPUTER MODEL DATA SHOWS THE
FRONT SHOULD REMAIN INLAND WITH SOUTH WINDS VEERING MORE
SOUTHEASTERLY MONDAY. LOW PRESSURE WILL FORM ALONG THE INLAND
PORTION OF THE FRONT ACROSS EASTERN GEORGIA/SOUTHERN SOUTH
CAROLINA MONDAY...AND AS THIS LOW PUSHES NORTHEASTWARD IT SHOULD
VEER WINDS MORE SOUTHWESTERLY TUESDAY. OUTSIDE OF THUNDERSTORMS
WIND SPEEDS SHOULD REMAIN LESS THAN 15 KNOTS THROUGH THE
PERIOD...STRONGEST SUNDAY NIGHT INTO MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH/SHK
SHORT TERM...MAC
LONG TERM...TRA
AVIATION...SGL/RJD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
832 PM EDT SAT SEP 6 2014
.SYNOPSIS...
HIGH PRESSURE...BRINGING IN COOLER AND DRIER AIR...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 /00Z SUNDAY THROUGH THURSDAY/...
BACK EDGE OF CLOUDS HAS FINALLY WORKED INTO THE TAFS WITH KDAY
GOING SCATTERED JUST BEFORE 00Z. HAVE THE BACK EDGE TIMED TO THE
OTHER TAFS BETWEEN 01Z-02Z. SKIES SHOULD REMAIN CLEAR FOR THE REST
OF THE NIGHT.
NORTHERLY WINDS BRINGING DRIER AIR SHOULD REDUCE THE CHANCES OF
FOG AROUND SUNRISE SUNDAY. WENT AHEAD AND KEPT THE VSBYS VFR.
CU RULE IS INDICATING FEW TO SCATTERED CU DEVELOPING LATE SUNDAY
MORNING...WITH THE SLIGHTLY BETTER COVERAGE IN THE NORTH.
WINDS WILL TURN FROM THE NORTH TO NORTHEAST TOMORROW...BUT WILL
REMAIN BELOW 10 MPH.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE WEDNESDAY AFTERNOON INTO
THURSDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS/SITES
NEAR TERM...SITES
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
802 PM EDT SAT SEP 6 2014
.SYNOPSIS...
COLD FRONT MOVES EAST TONIGHT. FRONT SLOWS DOWN AS IT CREEPS SOUTH
OF AREA SUNDAY. WEAK HIGH PRESSURE SUNDAY AFTERNOON GRADUALLY MOVES
AWAY MONDAY AND TUESDAY. COLD FRONT THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH SUNDAY/...
20Z SURFACE OBSERVATIONS SHOW A COLD FRONT WIND SHIFT ALONG THE OH
RIVER. CONVECTION AHEAD OF THE COLD FRONT...WITH VERY HEAVY RAIN
WILL CONTINUE TO MOVE EAST BEFORE GRADUALLY DIMINISH IN INTENSITY.
ADJUSTED CATEGORICAL POPS PER LATEST RADAR TRENDS...DECREASING
POPS TO LIKELY AND CHANCE THIS EVENING. PCPN SHOULD EXIT THE AREA
OF DISSIPATE BY MIDNIGHT.
COOLING SHOWERS HAVE DECREASED AFTERNOON TEMPERATURES ALONG THEIR
PATH.
PREVIOUS DISCUSSION BELOW...
AT 18Z APPEARS TO BE ALONG THE OHIO RIVER. CONVECTION HAS FIRE UP
OUT AHEAD OF THE FRONT...AS EXPECTED. FRONTAL BOUNDARY WILL
CONTINUE TO SAG SOUTHWARD TODAY...EVENTUALLY SLOWING DOWN AS IT
REACHES SOUTHERN ZONES...BUT PROGGED TO PASS SOUTH OF THE CWA BY
LATE TONIGHT OR EARLY SUNDAY. DRIER AIR WILL GRADUALLY FILTER IN
BEHIND THE FRONT FOR SUNDAY...WITH DEW POINTS POSSIBLY GETTING
DOWN INTO THE LOWER 50S ACROSS SOUTHEAST OHIO AND ADJACENT WV/ERN
KY COUNTIES BY SUNDAY EVENING. STILL LOOKING LIKE PLENTY OF
STRATUS WILL DEVELOP/LINGER ACROSS SOUTHERN HALF OF CWA
TONIGHT...WITH SOME CLEARING ACROSS THE NORTH...I.E. SOUTHEAST
OHIO ZONES. COULD BE SOME PATCHY FOG DEVELOPMENT ACROSS THE
NORTH...BUT BOUNDARY LAYER WINDS SHOULD REMAIN STRONG ENOUGH TO
PREVENT MUCH FORMATION.
DRIER WEATHER EXPECTED FOR SUNDAY. DID ELECT TO LEAVE A SLIGHT
CHANCE OF SHOWERS IN TOMORROW ACROSS THE EXTREME SOUTH DURING
DAYTIME HEATING HOURS WHERE GREATER MOISTURE WILL EXIST.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
HIGH PRESSURE SITS WELL NE OF THE AREA WHILE A WARM WAVE TRACKS NEWD
ALONG THE MIDDLE ATLANTIC COAST...WELL SE OF THE AREA THIS PERIOD.
THIS LEAVES FCST AREA IN LIGHT SE SFC FLOW. THE FRONT CROSSING THE
AREA THIS AFTERNOON AND TONIGHT...LIKE ITS PREDECESSOR...DOES NOT
GET THAT FAR S OF THE AREA...ALLOWING DEW POINTS TO RECOVER THIS
PERIOD. WITH WEAK UPPER LEVEL S/W TROUGHS PASSING EACH DAY IN
OTHERWISE NEAR WEAK ZONAL SOUTHERN STREAM FLOW...EXPECT DIURNAL
CONVECTION AGAIN...MAINLY ACROSS THE S AND THE HIGHER TERRAIN.
EMPLOYED A BIAS CORRECTED BLEND FOR LOWS SUN NT AND THEN LITTLE IF
ANY CHANGES TO TEMPERATURES BEYOND THAT...AS THE PREVIOUS FCST SPLIT
MOST DIFFERENCES AMONG THE LATEST GUIDANCE.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
IT APPEARS THE LATE SUMMER PATTERN WILL BE TRANSITIONING TO ONE MORE
TYPICAL OF AUTUMN...DRY WITH COLD FRONTS EVERY SEVERAL DAYS.
THE COLD FRONT LEADING THE CHARGE IS DRIVEN INITIALLY BY A LEAD S/W
TROUGH OVER THE MIDWEST MIDWEEK. BY THIS TIME...THE UPPER LEVEL
FLOW BECOMES MUCH MORE EVENLY SPLIT BETWEEN THE SRN AND NRN
STREAMS...THE FORMER ACROSS THE NRN CONUS...THE LATTER ALL THE WAY
UP ACROSS NRN CANADA. 12Z MODELS SEEM TO HAVE COME CLOSER TOGETHER
ON BEHAVIOR ON THE LEAD S/W AND A STRONGER...TRAILING S/W WHICH
CLOSES OFF. THE TIMING OF THE FRONTAL PASSAGE SEEMS TO HAVE
CONVERGED ON THU NT AS A RESULT...SO ASSOCIATED SHOWERS AND
THUNDERSTORMS ARE MORE LIKELY ON THU VS WED. SPC HAS SLIGHT RISK
JUST UPSTREAM ON WED.
THE CANADIAN HIGH PRESSURE SYSTEM REPRESENTING THE FIRST AUTUMN AIR
MASS IN THE PATTERN TRANSITION PLUMMETING INTO THE CONUS...IS
RATHER LARGE...AND WILL KEEP THE DRY...COOLER WEATHER...ONCE IT GETS
HERE...GOING THROUGH THE BALANCE OF THE EXTENDED PERIOD.
USED WPC AND BIAS CORRECTED ECMWFHIRES BEGINNING AND END OF PERIOD.
PREVIOUS LOOKED GOOD IN BETWEEN. BASICALLY SPLIT THE GUIDANCE IN
THE WAKE OF THE FRONT...WITH QUESTION AS TO HOW MUCH OF A PUSH OF
THE COOLER...DRIER AIR THERE WILL BE IN THE WAKE OF THE FIRST
S/W...VS HOW MUCH OF IT WAITS UNTIL THE PASSAGE OF THE SECOND.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
CHALLENGING FORECAST TONIGHT. FRONTAL BOUNDARY SLOWLY DRIFTING
EAST FROM HTS...NORTHEAST TO EKN. THIS FRONT SHOWS VERY LITTLE
MOVEMENT ALTHOUGH RADAR IMAGES SHOW SIGNS OF CONVECTION DECREASING
IN INTENSITY. BRIEF MVFR/IFR CEILINGS AND VISIBILITIES ALONG
DECAYING RAINFALL ACTIVITY WILL CONTINUE THROUGH AROUND SUNSET.
HEAVY RAINFALL WAS REPORTED AT CRW...HTS...CKB...WITH LITTLE OR NO
PCPN OVER BKW AND PKB. THE NAM SUGGEST BOUNDARY LAYER WINDS OF 10
KNOTS OR LESS WILL PREVAIL OVERNIGHT...WHILE THE RAP INDICATE 15
KNOTS. SFC OBS SHOW NORTHERLY FLOW UPSTREAM ACROSS NORTHERN OH AND
WESTERN PA.
THE CHALLENGE STRIKES EITHER IF DENSE POST RAINFALL FOG WILL
MATERIALIZE AND ITS TIMING OVERNIGHT. CLOUD COVER WILL PLAY AN
IMPORTANT ROLE IN RADIATION FOG OVERNIGHT. SATELLITE IMAGES SHOW A
MID TO LOW LEVEL DECK OF CLOUDS WELL WEST OF THE ACTUAL FRONT AND
ITS ASSOCIATED CONVECTION. SFC DEWPOINTS REMAIN IN THE MID TO
UPPER 60S. THEREFORE...EXPECT A GREAT DEAL OF LOW LEVEL STRATUS TO
DEVELOP BEHIND THE FRONT MAINLY AFTER 06Z...EXCEPT EARLIER OVER
SITES THAT RECEIVED RAINFALL. OTHERWISE...DENSE POST RAINFALL FOG
WILL DEVELOP MIDNIGHT THROUGH AT LEAST SUNRISE SUNDAY MORNING.
WIDESPREAD MVFR/IFR STRATUS TO DEVELOP...PARTICULARLY AT
HTS...CRW...CKB AND PERHAPS EKN TOO. STRATUS SHOULD LIFT AFTER
14-16Z WITH A RETURN OF VFR CONDITIONS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF SHOWERS AND THUNDERSTORMS COULD
VARY. DEVELOPMENT AND HEIGHT OF STRATUS TONIGHT COULD VARY FROM
FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SUN 09/07/14
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY H H M M H H L L L L L L
HTS CONSISTENCY H H M M L L L L L L L L
BKW CONSISTENCY H H H H M L M M M M M M
EKN CONSISTENCY H L L L L L L L M M M L
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H M M M M M H H H
AFTER 00Z MONDAY...
IFR VALLEY FOG POSSIBLE MONDAY MORNING..AND IN SHOWERS AND
THUNDERSTORMS THURSDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/SL
NEAR TERM...ARJ/SL
SHORT TERM...TRM
LONG TERM...TRM
AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1201 PM EDT FRI SEP 5 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC
COAST TODAY. A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE STATE ON
SATURDAY. HIGH PRESSURE OVER THE MIDWEST WILL THEN SLIDE ACROSS
PENNSYLVANIA SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
REGIONAL VIS LOOP SHOWING STUBBORN LOW CLOUDS/AND SOME 3-4SM FOG
LINGERING THROUGHOUT THE LOWER SUSQ VALLEY WITHIN THE REGION OF
HIGHEST MOISTURE AND WEAK LLVL...SERLY FLOW.
THIS CLOUD AREA WILL SLOWLY ERODE FROM ITS EDGES THROUGH
18Z...KEEPING TEMPS A FEW DEG F BEHIND THOSE ELSEWHERE ACROSS THE
CWA. EXPECT A QUICK SPIKE IN THE TEMPS IN THE LOWER SUSQ REGION
AFTER 18Z UNDER PLENTY OF SUNSHINE THERE...AND AREA-WIDE.
IT DOESN/T GET ANY SOUPIER IN SEPTEMBER HERE IN CENTRAL PENN THAN
IT WAS EARLIER THIS MORNING...WITH DENSE FOG IN THE U60S TO LOWER
70S.
HIGHEST PWAT AIR /NEAR 2.0 INCHES/ AND COOLEST MID-LEVEL TEMPS OF
JUST AROUND 7C WILL BE FOUND ACROSS THE LOWER SUSQ VALLEY THIS
AFTERNOON. IN CONTRAST...THE LOWEST PWATS AND WARMER TEMPS ALOFT
/8-9C AT 700 MB/ WILL OCCUR ACROSS THE KBFD VCNTY AND POINTS WEST.
LATEST HRRR CONFINES PRACTICALLY ALL OF THE MID TO LATE AFTERNOON
CONVECTION ACROSS FAR SCENT PENN AND THE LOWER SUSQ VALLEY...WITH
JUST A SPECKLING OF A FEW STRAY SHOWERS/TSRA NEAR THE ALLEGHENY
FRONT UP TO I-80.
THEREFORE...THE CURRENT RUNNING FCST OF ISOLATED TO SCATTERED
SHOWERS AND TSRA ACROSS SOUTHERN PENN AND THE LOWER SUSQ VALLEY
LOOKS IN GOOD SHARP ATTM WITH MINIMAL CHANGES EXPECTED WITH THIS
MIDDAY UPDATE. A RIBBON OF LOWER PWAT AIR WILL BE SITUATED ACROSS
THE REGION NORTH OF A LINE FROM KBFD TO KUNV AND KAVP.
AS THE ISOLATED-SCT PULSE-TYPE TSRA DEVELOP ACROSS THE SOUTHERN
COUNTIES DURING THE AFTN...WILL HAVE TO WATCH FOR LOCALLY
EXCESSIVE RAINFALL...AS ANY STORMS WILL BE SLOW-MOVERS DUE TO
WEAK FLOW ALOFT. CONVECTION-ALLOWING MDL DATA HINTS AT THIS
POTENTIAL WITH SPOT AMTS OF OVR 3 INCHES ACROSS THE LOWER SUSQ
VALLEY.
GEFS 925/850 TEMPS SUPPORT HIGH TEMPS IN THE M-U80S...WITH THE
GREATEST DEPARTURES FROM AVERAGE ACROSS THE W MTNS. WHEN COMBINED
WITH HIGH HUMIDITY...APPARENT TEMPS WILL RANGE FROM THE U80S TO
L90S...PERHAPS THE WARMEST WE/LL SEE UNTIL NEXT YEAR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
IN THE ABSENCE OF LG SCALE FORCING...DIURNALLY-DRIVEN SCT
CONVECTION ACROSS SOUTHERN PA SHOULD DIE OFF SHORTLY AFTER SUNSET.
TRANQUIL AND VERY WARM CONDS EXPECTED FOR THE REST OF THE NIGHT
OVR MOST OF CENTRAL PA...AS COLD FRONT REMAINS WEST OF THE AREA.
MDL TIMING OF COLD FRONT SUGGESTS SHRA/TSRA WILL MOVE INTO THE NW
MTNS ARND OR SHORTLY AFTER DAWN SATURDAY.
HAVE INCREASED POPS TO NR 80 PCT SATURDAY FOR PASSAGE OF COLD
FRONT BASED ON ABUNDANCE OF PRE-FRONTAL MOISTURE AND FAIRLY STRONG
FORCING AHEAD OF APPROACHING SHORTWAVE...AS IMPLIED BY MDL
500-300MB Q-VEC CONVERGENCE FIELDS. GEFS PWATS RUNNING BTWN 1-2SD
ABV NORMAL IN ADVANCE OF CDFRONT. 00Z GEFS/03Z SREF DATA ALSO
BOTH SUPPORT CATEGORICAL POPS ACROSS MOST OF CENTRAL PA. MORNING
SHOWERS ACROSS THE NW MTNS SHOULD GIVE WAY TO PM TSRA OVR THE
SOUTHERN COUNTIES...WHERE EARLY HEATING WILL RESULT IN A
MODERATELY UNSTABLE PRE-FRONTAL AIR MASS BY AFTN. HOWEVER...FAIRLY
MODEST MID LVL WINDS AND DEEP LYR SHEAR POINT TOWARD A LIMITED SVR
WX THREAT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
*COOLER/DRY WEATHER SUNDAY INTO MONDAY
*NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU
THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS
THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS
SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST
AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK
/SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A
TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS
SOUTH CENTRAL CANADA.
AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER
NEWFOUNDLAND/LABRADOR WILL BE PASSING SOUTH OF PA SAT NIGHT. A
MODIFIED CANADIAN HIGH BUILDING SWD INTO THE CENTRAL PLAINS WILL
EVENTUALLY SHIFT EWD THROUGH THE NORTHEAST STATES AND MOVE INTO
THE MARITIMES BY NEXT WED.
SHRA/TSRA WILL END FROM NW-SE SAT NGT WITH MUCH DRIER AIR
FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO EARLY NEXT
WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS TO THE SOUTH
OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF A COOL-AIR
WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR AVG.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
LINGERING...PATCHY 3-4SM FOG AND IFR CIGS ACROSS THE LOWER SUSQ
VALLEY WILL DISSIPATE BETWEEN 17-18Z. ELSWHERE...PLENTY OF SUNSHINE
WILL OCCUR WITH VSBYS IN THE 5-10SM RANGE FOR THE REST OF TODAY.
FOCUS THIS AFTERNOON SHIFTS TOWARD POTENTIAL FOR SCT DIURNAL
CONVECTION ACROSS FAR SRN AND SOUTHEAST PA. PWATS ARE PROJECTED TO
APPROACH 2 INCHES IN THIS AREA AND HEATING OF THIS MOIST/UNSTABLE
AIR MASS SHOULD RESULT IN MODERATE CAPES OF ARND 2000J/JG ACROSS
THE LOWER SUSQ VALLEY BASED ON LATEST OPER MODEL AND GEFS OUTPUT.
SCT PULSE- TYPE TSRA SHOULD DEVELOP ACROSS THE SOUTHERN COUNTIES
BRINGING LOCAL RESTRICTIONS AS CONVECTIVE TEMP IS REACHED DURING
THE AFTN...AND ANY STORMS WILL BE SLOW- MOVERS DUE TO WEAK FLOW
ALOFT.
HIGH DEWPOINTS REMAIN IN PLACE TONIGHT AHEAD OF AN APPROACHING
COLD FRONT. THIS WILL LEAD TO REDEVELOPMENT OF FOG/HAZE...AND AN
ENCROACHING MVFR CLOUD DECK ALONG WITH A CHANCE FOR SHOWERS AFTER
06Z IN THE NW.
OUTLOOK...
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS
ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
TUE...CHC SHOWERS/TSTMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD/LAMBERT
NEAR TERM...FITZGERALD/LAMBERT
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/STEINBUGL
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
751 AM EDT FRI SEP 5 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC
COAST TODAY. A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE STATE ON
SATURDAY. HIGH PRESSURE OVER THE MIDWEST WILL THEN SLIDE ACROSS
PENNSYLVANIA SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
11-3.9 MICRON SATL IMAGERY SHOWING EXTENSIVE FOG IN THE VALLEYS OF
CENTRAL PA EARLY THIS MORNING...AS WELL AS STRATUS ACROSS EASTERN
PA. THE LOW CLOUDS AND FOG SHOULD BURN OFF BY 13Z-14Z BASED ON
CLIMATOLOGY AND LATEST HRRR OUTPUT. FOCUS THEN SHIFTS TOWARD
POTENTIAL OF SCT DIURNAL CONVECTION ACROSS SOUTHEAST PA. PWATS ARE
PROJECTED TO APPROACH 2 INCHES IN THIS AREA AND HEATING OF THIS
MOIST/UNSTABLE AIR MASS SHOULD RESULT IN MODERATE CAPES OF ARND
2000J/JG BY THIS AFTN ACROSS THE LOWER SUSQ VALLEY BASED ON
LATEST OPER MODEL AND GEFS OUTPUT. SCT PULSE-TYPE TSRA SHOULD
DEVELOP ACROSS THE SOUTHERN COUNTIES AS CONVECTIVE TEMP IS REACHED
DURING THE AFTN. WILL HAVE TO WATCH FOR LOCALLY EXCESSIVE
RAINFALL...AS ANY STORMS WILL BE SLOW-MOVERS DUE TO WEAK FLOW
ALOFT. CONVECTION-ALLOWING MDL DATA HINTS AT THIS POTENTIAL WITH
SPOT AMTS OF OVR 3 INCHES ACROSS THE LOWER SUSQ VALLEY.
GEFS 925/850 TEMPS SUPPORT HIGH TEMPS IN THE M-U80S...WITH THE
GREATEST DEPARTURES FROM AVERAGE ACROSS THE W MTNS. WHEN COMBINED
WITH HIGH HUMIDITY...APPARENT TEMPS WILL RANGE FROM THE U80S TO
L90S...PERHAPS THE WARMEST WE/LL SEE UNTIL NEXT YEAR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
IN THE ABSENCE OF LG SCALE FORCING...DIURNALLY-DRIVEN SCT
CONVECTION ACROSS SOUTHERN PA SHOULD DIE OFF SHORTLY AFTER SUNSET.
TRANQUIL AND VERY WARM CONDS EXPECTED FOR THE REST OF THE NIGHT
OVR MOST OF CENTRAL PA...AS COLD FRONT REMAINS WEST OF THE AREA.
MDL TIMING OF COLD FRONT SUGGESTS SHRA/TSRA WILL MOVE INTO THE NW
MTNS ARND OR SHORTLY AFTER DAWN SATURDAY.
HAVE INCREASED POPS TO NR 80 PCT SATURDAY FOR PASSAGE OF COLD
FRONT BASED ON ABUNDANCE OF PRE-FRONTAL MOISTURE AND FAIRLY STRONG
FORCING AHEAD OF APPROACHING SHORTWAVE...AS IMPLIED BY MDL
500-300MB Q-VEC CONVERGENCE FIELDS. GEFS PWATS RUNNING BTWN 1-2SD
ABV NORMAL IN ADVANCE OF CDFRONT. 00Z GEFS/03Z SREF DATA ALSO
BOTH SUPPORT CATEGORICAL POPS ACROSS MOST OF CENTRAL PA. MORNING
SHOWERS ACROSS THE NW MTNS SHOULD GIVE WAY TO PM TSRA OVR THE
SOUTHERN COUNTIES...WHERE EARLY HEATING WILL RESULT IN A
MODERATELY UNSTABLE PRE-FRONTAL AIR MASS BY AFTN. HOWEVER...FAIRLY
MODEST MID LVL WINDS AND DEEP LYR SHEAR POINT TOWARD A LIMITED SVR
WX THREAT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
*COOLER/DRY WEATHER SUNDAY INTO MONDAY
*NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU
THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS
THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS
SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST
AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK
/SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A
TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS
SOUTH CENTRAL CANADA.
AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER
NEWFOUNDLAND/LABRADOR WILL BE PASSING SOUTH OF PA SAT NIGHT. A
MODIFIED CANADIAN HIGH BUILDING SWD INTO THE CENTRAL PLAINS WILL
EVENTUALLY SHIFT EWD THROUGH THE NORTHEAST STATES AND MOVE INTO
THE MARITIMES BY NEXT WED.
SHRA/TSRA WILL END FROM NW-SE SAT NGT WITH MUCH DRIER AIR
FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO EARLY NEXT
WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS TO THE SOUTH
OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF A COOL-AIR
WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR AVG.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
MID DECK SLIDING INTO THE NW HAS AIDED IN LIFTING OF MORE DENSE
FOG AT KBFD...BUT THICKER FOG DEVELOPED ACROSS PORTIONS OF CENTRAL
AND SOUTHERN MTNS AROUND SUNRISE WITH VARIABLE MVFR TO IFR
CONDITIONS. THICKEST FOG WILL DISSIPATE RATHER QUICKLY /BY 13Z/
BUT MVFR CONDITIONS COULD LINGER INTO THE MID/LATE MORNING IN SOME
LOCATIONS.
ONCE MORNING FOG MIXES OUT...VSBYS WILL RANGE FROM 5-10SM WITH VFR
CIGS. FOCUS THEN SHIFTS TOWARD POTENTIAL FOR SCT DIURNAL
CONVECTION ACROSS SOUTHEAST PA. PWATS ARE PROJECTED TO APPROACH 2
INCHES IN THIS AREA AND HEATING OF THIS MOIST/UNSTABLE AIR MASS
SHOULD RESULT IN MODERATE CAPES OF ARND 2000J/JG ACROSS THE LOWER
SUSQ VALLEY BASED ON LATEST OPER MODEL AND GEFS OUTPUT. SCT PULSE-
TYPE TSRA SHOULD DEVELOP ACROSS THE SOUTHERN COUNTIES BRINGING
LOCAL RESTRICTIONS AS CONVECTIVE TEMP IS REACHED DURING THE
AFTN...AND ANY STORMS WILL BE SLOW- MOVERS DUE TO WEAK FLOW ALOFT.
HIGH DEWPOINTS REMAIN IN PLACE TONIGHT AHEAD OF AN APPROACHING
COLD FRONT. THIS WILL LEAD TO REDEVELOPMENT OF FOG/HAZE...AND AN
ENCROACHING MVFR CLOUD DECK ALONG WITH A CHANCE FOR SHOWERS AFTER
06Z IN THE NW.
OUTLOOK...
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS
ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
TUE...CHC SHOWERS/TSTMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/STEINBUGL
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
547 AM EDT FRI SEP 5 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC
COAST TODAY. A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE STATE ON
SATURDAY. HIGH PRESSURE OVER THE MIDWEST WILL THEN SLIDE ACROSS
PENNSYLVANIA SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
11-3.9 MICRON SATL IMAGERY SHOWING EXTENSIVE FOG IN THE VALLEYS OF
CENTRAL PA EARLY THIS MORNING...AS WELL AS STRATUS ACROSS EASTERN
PA. THE LOW CLOUDS AND FOG SHOULD BURN OFF BY 13Z-14Z BASED ON
CLIMATOLOGY AND LATEST HRRR OUTPUT. FOCUS THEN SHIFTS TOWARD
POTENTIAL OF SCT DIURNAL CONVECTION ACROSS SOUTHEAST PA. PWATS ARE
PROJECTED TO APPROACH 2 INCHES IN THIS AREA AND HEATING OF THIS
MOIST/UNSTABLE AIR MASS SHOULD RESULT IN MODERATE CAPES OF ARND
2000J/JG BY THIS AFTN ACROSS THE LOWER SUSQ VALLEY BASED ON
LATEST OPER MODEL AND GEFS OUTPUT. SCT PULSE-TYPE TSRA SHOULD
DEVELOP ACROSS THE SOUTHERN COUNTIES AS CONVECTIVE TEMP IS REACHED
DURING THE AFTN. WILL HAVE TO WATCH FOR LOCALLY EXCESSIVE
RAINFALL...AS ANY STORMS WILL BE SLOW-MOVERS DUE TO WEAK FLOW
ALOFT. CONVECTION-ALLOWING MDL DATA HINTS AT THIS POTENTIAL WITH
SPOT AMTS OF OVR 3 INCHES ACROSS THE LOWER SUSQ VALLEY.
GEFS 925/850 TEMPS SUPPORT HIGH TEMPS IN THE M-U80S...WITH THE
GREATEST DEPARTURES FROM AVERAGE ACROSS THE W MTNS. WHEN COMBINED
WITH HIGH HUMIDITY...APPARENT TEMPS WILL RANGE FROM THE U80S TO
L90S...PERHAPS THE WARMEST WE/LL SEE UNTIL NEXT YEAR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
IN THE ABSENCE OF LG SCALE FORCING...DIURNALLY-DRIVEN SCT
CONVECTION ACROSS SOUTHERN PA SHOULD DIE OFF SHORTLY AFTER SUNSET.
TRANQUIL AND VERY WARM CONDS EXPECTED FOR THE REST OF THE NIGHT
OVR MOST OF CENTRAL PA...AS COLD FRONT REMAINS WEST OF THE AREA.
MDL TIMING OF COLD FRONT SUGGESTS SHRA/TSRA WILL MOVE INTO THE NW
MTNS ARND OR SHORTLY AFTER DAWN SATURDAY.
HAVE INCREASED POPS TO NR 80 PCT SATURDAY FOR PASSAGE OF COLD
FRONT BASED ON ABUNDANCE OF PRE-FRONTAL MOISTURE AND FAIRLY STRONG
FORCING AHEAD OF APPROACHING SHORTWAVE...AS IMPLIED BY MDL
500-300MB Q-VEC CONVERGENCE FIELDS. GEFS PWATS RUNNING BTWN 1-2SD
ABV NORMAL IN ADVANCE OF CDFRONT. 00Z GEFS/03Z SREF DATA ALSO
BOTH SUPPORT CATEGORICAL POPS ACROSS MOST OF CENTRAL PA. MORNING
SHOWERS ACROSS THE NW MTNS SHOULD GIVE WAY TO PM TSRA OVR THE
SOUTHERN COUNTIES...WHERE EARLY HEATING WILL RESULT IN A
MODERATELY UNSTABLE PRE-FRONTAL AIR MASS BY AFTN. HOWEVER...FAIRLY
MODEST MID LVL WINDS AND DEEP LYR SHEAR POINT TOWARD A LIMITED SVR
WX THREAT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
*COOLER/DRY WEATHER SUNDAY INTO MONDAY
*NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU
THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS
THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS
SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST
AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK
/SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A
TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS
SOUTH CENTRAL CANADA.
AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER
NEWFOUNDLAND/LABRADOR WILL BE PASSING SOUTH OF PA SAT NIGHT. A
MODIFIED CANADIAN HIGH BUILDING SWD INTO THE CENTRAL PLAINS WILL
EVENTUALLY SHIFT EWD THROUGH THE NORTHEAST STATES AND MOVE INTO
THE MARITIMES BY NEXT WED.
SHRA/TSRA WILL END FROM NW-SE SAT NGT WITH MUCH DRIER AIR
FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO EARLY NEXT
WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS TO THE SOUTH
OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF A COOL-AIR
WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR AVG.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
OBS AND SATL IMAGERY SHOWING VALLEY FOG ACROSS NORTHWEST PA EARLY
THIS MORNING. CONTINUED RADIATIONAL COOLING UNDER MCLEAR SKIES
AND A LIGHT WIND WILL CAUSE VALLEY FOG AND A THIN STRATOCU DECK TO
BECOME MORE WIDESPREAD ACROSS CENTRAL PA WITH LOCALLY DENSE FOG
EXPECTED...ESP IN THE DEEP RIVER/STREAM VALLEYS OF THE
ALLEGHENIES. MANY LOCATIONS LIKELY TO EXPERIENCE A PERIOD OF IFR-
LIFR CONDS NEAR DAWN.
FOG SHOULD BURN OFF BY 14Z...WITH HAZE POTENTIALLY LINGERING
THROUGH MID/LATE MORNING IN THE SE. FOCUS THEN SHIFTS TOWARD
POTENTIAL FOR SCT DIURNAL CONVECTION ACROSS SOUTHEAST PA. PWATS
ARE PROJECTED TO APPROACH 2 INCHES IN THIS AREA AND HEATING OF
THIS MOIST/UNSTABLE AIR MASS SHOULD RESULT IN MODERATE CAPES OF
ARND 2000J/JG ACROSS THE LOWER SUSQ VALLEY BASED ON LATEST OPER
MODEL AND GEFS OUTPUT. SCT PULSE- TYPE TSRA SHOULD DEVELOP ACROSS
THE SOUTHERN COUNTIES BRINGING LOCAL RESTRICTIONS AS CONVECTIVE
TEMP IS REACHED DURING THE AFTN...AND ANY STORMS WILL BE SLOW-
MOVERS DUE TO WEAK FLOW ALOFT.
OUTLOOK...
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS
ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
TUE...CHC SHOWERS/TSTMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/STEINBUGL
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
416 AM EDT FRI SEP 5 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC
SEABOARD TONIGHT BRINGING VERY WARM AND HUMID CONDITIONS FOR
FRIDAY. A COLD FRONT WILL MOVE EAST FROM THE OHIO VALLEY AND
CROSS THE STATE SATURDAY AFTERNOON AND EVENING. A REFRESHINGLY
COOLER AND MUCH DRIER AIRMASS WILL OVERSPREAD THE REGION FOR
SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
11-3.9 MICRON SATL IMAGERY ALREADY SHOWING THE PRESENCE OF VALLEY
FOG ACROSS NORTHWEST PA AT 06Z. CONTINUED RADIATIONAL COOLING
UNDER MCLEAR SKIES AND A LIGHT WIND WILL CAUSE VALLEY FOG TO
BECOME MORE WIDESPREAD ACROSS CENTRAL PA WITH LOCALLY DENSE FOG
EXPECTED...ESP IN THE DEEP RIVER/STREAM VALLEYS OF THE
ALLEGHENIES. MINS TEMPS WILL RANGE FROM NEAR 60F ACROSS THE NW
MTNS...TO NR 70F IN THE VALLEYS EAST OF THE ALLEGHENIES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
ANY EARLY AM FOG SHOULD BURN OFF BY 13Z-14Z BASED ON CLIMATOLOGY
AND LATEST HRRR OUTPUT. FOCUS THEN SHIFTS TOWARD POTENTIAL OF SCT
DIURNAL CONVECTION ACROSS SOUTHEAST PA. PWATS ARE PROJECTED TO
APPROACH 2 INCHES IN THIS AREA AND HEATING OF THIS MOIST/UNSTABLE
AIR MASS SHOULD RESULT IN MODERATE CAPES OF ARND 2000J/JG ACROSS
THE LOWER SUSQ VALLEY BASED ON LATEST OPER MODEL AND GEFS OUTPUT.
SCT PULSE-TYPE TSRA SHOULD DEVELOP ACROSS THE SOUTHERN COUNTIES AS
CONVECTIVE TEMP IS REACHED DURING THE AFTN. WILL HAVE TO WATCH FOR
LOCALLY EXCESSIVE RAINFALL...AS ANY STORMS WILL BE SLOW-MOVERS DUE
TO WEAK FLOW ALOFT. CONVECTION-ALLOWING MDL DATA HINTS AT THIS
POTENTIAL WITH SPOT AMTS OF OVR 3 INCHES ACROSS THE LOWER SUSQ
VALLEY.
GEFS 925/850 TEMPS SUPPORT HIGH TEMPS IN THE M-U80S...WITH THE
GREATEST DEPARTURES FROM AVERAGE ACROSS THE W MTNS. WHEN COMBINED
WITH HIGH HUMIDITY...APPARENT TEMPS WILL RANGE FROM THE U80S TO
L90S...PERHAPS THE WARMEST WE/LL SEE UNTIL NEXT YEAR.
A COLD FRONT WILL BE APPROACHING FROM THE GREAT LAKES ON FRIDAY
NIGHT AND PUSH THRU DURING THE DAY SAT. THE POPS WILL STAY RATHER
LOW OVER MOST OF THE AREA WITH ONLY SCT SHRA/TSRA OVERNIGHT...AND
MAINLY LIMITED TO THE NW ZONES. THE NWRN COUNTIES WILL LIKELY SEE
STORMS MOVE DOWN FROM THE NW AFTER MIDNIGHT...BEFORE GRADUALLY
WEAKENING AS THEY APPROACH THE RIDGE AND VALLEY REGION OF CENTRAL
PENN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
*SHOWERS/TSTMS ON SATURDAY FOLLOWED BY COOLER/DRY WEATHER SUNDAY
INTO MONDAY
*NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU
THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS
THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS
SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST
AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK
/SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A
TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS
SOUTH CENTRAL CANADA.
AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER
NEWFOUNDLAND/LABRADOR WILL BE THE FOCUS FOR SHOWERS/TSTMS AS IT
CROSSES THE APPALACHIANS ON SAT. A MODIFIED CANADIAN HIGH BUILDING
SWD INTO THE CENTRAL PLAINS WILL EVENTUALLY SHIFT EWD THROUGH THE
NORTHEAST STATES AND MOVE INTO THE MARITIMES BY NEXT WED.
WEAK HEIGHT FALLS WILL OVERSPREAD THE REGION ON SAT...AS A POSITIVE
TILT S/WV TROUGH MOVES EWD FROM THE NRN PLAINS ACROSS THE GREAT
LAKES REGION. ABOVE NORMAL PWS ALONG/AHEAD OF THE LOW LEVEL BOUNDARY
AND SUFFICIENT HEATING/INSTABILITY SHOULD FOSTER NRMS SHOWERS AND
SCT TSTMS WITH SOME LOCALLY HEAVY DOWNPOURS. WITH THE STRONGEST BELT
OF MID-LEVEL FLOW AND DEEP-LAYER SHEAR EXPECTED TO REMAIN NORTH OF
THE AREA ACROSS ONT/QUE AND NRN NEW ENGLAND...THE RISK FOR SVR
STORMS IS LOW. THE PCPN WILL END FROM NW-SE SAT NGT WITH MUCH
DRIER AIR FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO
EARLY NEXT WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS
TO THE SOUTH OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF
A COOL-AIR WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR
AVG.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
OBS AND SATL IMAGERY SHOWING VALLEY FOG ACROSS NORTHWEST PA EARLY
THIS MORNING. CONTINUED RADIATIONAL COOLING UNDER MCLEAR SKIES
AND A LIGHT WIND WILL CAUSE VALLEY FOG AND A THIN STRATOCU DECK TO
BECOME MORE WIDESPREAD ACROSS CENTRAL PA WITH LOCALLY DENSE FOG
EXPECTED...ESP IN THE DEEP RIVER/STREAM VALLEYS OF THE
ALLEGHENIES. MANY LOCATIONS LIKELY TO EXPERIENCE A PERIOD OF IFR-
LIFR CONDS NEAR DAWN.
FOG SHOULD BURN OFF BY 14Z...WITH HAZE POTENTIALLY LINGERING
THROUGH MID/LATE MORNING IN THE SE. FOCUS THEN SHIFTS TOWARD
POTENTIAL FOR SCT DIURNAL CONVECTION ACROSS SOUTHEAST PA. PWATS
ARE PROJECTED TO APPROACH 2 INCHES IN THIS AREA AND HEATING OF
THIS MOIST/UNSTABLE AIR MASS SHOULD RESULT IN MODERATE CAPES OF
ARND 2000J/JG ACROSS THE LOWER SUSQ VALLEY BASED ON LATEST OPER
MODEL AND GEFS OUTPUT. SCT PULSE- TYPE TSRA SHOULD DEVELOP ACROSS
THE SOUTHERN COUNTIES BRINGING LOCAL RESTRICTIONS AS CONVECTIVE
TEMP IS REACHED DURING THE AFTN...AND ANY STORMS WILL BE SLOW-
MOVERS DUE TO WEAK FLOW ALOFT.
OUTLOOK...
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS
ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
TUE...CHC SHOWERS/TSTMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...STEINBUGL
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
235 AM EDT FRI SEP 5 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC
SEABOARD TONIGHT BRINGING VERY WARM AND HUMID CONDITIONS FOR
FRIDAY. A COLD FRONT WILL MOVE EAST FROM THE OHIO VALLEY AND
CROSS THE STATE SATURDAY AFTERNOON AND EVENING. A REFRESHINGLY
COOLER AND MUCH DRIER AIRMASS WILL OVERSPREAD THE REGION FOR
SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
11-3.9 MICRON SATL IMAGERY ALREADY SHOWING THE PRESENCE OF VALLEY
FOG ACROSS NORTHWEST PA AT 06Z. CONTINUED RADIATIONAL COOLING
UNDER MCLEAR SKIES AND A LIGHT WIND WILL CAUSE VALLEY FOG TO
BECOME MORE WIDESPREAD ACROSS CENTRAL PA WITH LOCALLY DENSE FOG
EXPECTED...ESP IN THE DEEP RIVER/STREAM VALLEYS OF THE
ALLEGHENIES. MINS TEMPS WILL RANGE FROM NEAR 60F ACROSS THE NW
MTNS...TO NR 70F IN THE VALLEYS EAST OF THE ALLEGHENIES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
ANY EARLY AM FOG SHOULD BURN OFF BY 13Z-14Z BASED ON CLIMATOLOGY
AND LATEST HRRR OUTPUT. FOCUS THEN SHIFTS TOWARD POTENTIAL OF SCT
DIURNAL CONVECTION ACROSS SOUTHEAST PA. PWATS ARE PROJECTED TO
APPROACH 2 INCHES IN THIS AREA AND HEATING OF THIS MOIST/UNSTABLE
AIR MASS SHOULD RESULT IN MODERATE CAPES OF ARND 2000J/JG ACROSS
THE LOWER SUSQ VALLEY BASED ON LATEST OPER MODEL AND GEFS OUTPUT.
SCT PULSE-TYPE TSRA SHOULD DEVELOP ACROSS THE SOUTHERN COUNTIES AS
CONVECTIVE TEMP IS REACHED DURING THE AFTN. WILL HAVE TO WATCH FOR
LOCALLY EXCESSIVE RAINFALL...AS ANY STORMS WILL BE SLOW-MOVERS DUE
TO WEAK FLOW ALOFT. CONVECTION-ALLOWING MDL DATA HINTS AT THIS
POTENTIAL WITH SPOT AMTS OF OVR 3 INCHES ACROSS THE LOWER SUSQ
VALLEY.
GEFS 925/850 TEMPS SUPPORT HIGH TEMPS IN THE M-U80S...WITH THE
GREATEST DEPARTURES FROM AVERAGE ACROSS THE W MTNS. WHEN COMBINED
WITH HIGH HUMIDITY...APPARENT TEMPS WILL RANGE FROM THE U80S TO
L90S...PERHAPS THE WARMEST WE/LL SEE UNTIL NEXT YEAR.
A COLD FRONT WILL BE APPROACHING FROM THE GREAT LAKES ON FRIDAY
NIGHT AND PUSH THRU DURING THE DAY SAT. THE POPS WILL STAY RATHER
LOW OVER MOST OF THE AREA WITH ONLY SCT SHRA/TSRA OVERNIGHT...AND
MAINLY LIMITED TO THE NW ZONES. THE NWRN COUNTIES WILL LIKELY SEE
STORMS MOVE DOWN FROM THE NW AFTER MIDNIGHT...BEFORE GRADUALLY
WEAKENING AS THEY APPROACH THE RIDGE AND VALLEY REGION OF CENTRAL
PENN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
*SHOWERS/TSTMS ON SATURDAY FOLLOWED BY COOLER/DRY WEATHER SUNDAY
INTO MONDAY
*NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU
THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS
THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS
SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST
AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK
/SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A
TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS
SOUTH CENTRAL CANADA.
AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER
NEWFOUNDLAND/LABRADOR WILL BE THE FOCUS FOR SHOWERS/TSTMS AS IT
CROSSES THE APPALACHIANS ON SAT. A MODIFIED CANADIAN HIGH BUILDING
SWD INTO THE CENTRAL PLAINS WILL EVENTUALLY SHIFT EWD THROUGH THE
NORTHEAST STATES AND MOVE INTO THE MARITIMES BY NEXT WED.
WEAK HEIGHT FALLS WILL OVERSPREAD THE REGION ON SAT...AS A POSITIVE
TILT S/WV TROUGH MOVES EWD FROM THE NRN PLAINS ACROSS THE GREAT
LAKES REGION. ABOVE NORMAL PWS ALONG/AHEAD OF THE LOW LEVEL BOUNDARY
AND SUFFICIENT HEATING/INSTABILITY SHOULD FOSTER NRMS SHOWERS AND
SCT TSTMS WITH SOME LOCALLY HEAVY DOWNPOURS. WITH THE STRONGEST BELT
OF MID-LEVEL FLOW AND DEEP-LAYER SHEAR EXPECTED TO REMAIN NORTH OF
THE AREA ACROSS ONT/QUE AND NRN NEW ENGLAND...THE RISK FOR SVR
STORMS IS LOW. THE PCPN WILL END FROM NW-SE SAT NGT WITH MUCH
DRIER AIR FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO
EARLY NEXT WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS
TO THE SOUTH OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF
A COOL-AIR WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR
AVG.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS SKIES CLEAR TONIGHT...AND AS WINDS LIGHTEN...LOCALLY DENSE AND
MAINLY DEEPER VALLEY FOG IS POSSIBLE LATE TONIGHT THROUGH MID
FRIDAY MORNING. MANY LOCATIONS LIKELY TO EXPERIENCE A PERIOD OF
IFR-LIFR CONDS NEAR DAWN FRIDAY.
CONDITIONS WILL GRADUALLY IMPROVE LATE FRI MORNING AND AFTERNOON
WITH A FEW AREAS OF MVFR HAZE LINGERING /ESPECIALLY INVOF KMDT AND
KLNS/. ISOLATED SHRA/TSRA FRIDAY AFTERNOON WILL BRING THE
POTENTIAL FOR BRIEF MVFR CONDITIONS.
OUTLOOK...
FRI...PATCHY AM FOG. ISOLD PM TSRA IMPACTS POSS SOUTHERN PA.
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
330 PM CDT FRI SEP 5 2014
.DISCUSSION...
BASED ON THE EXPECTED OVERNIGHT LOW TEMPS...CURRENT TOVER VALUES ARE
NEAR 0 AT BNA...AND -3 AT BOTH CKV AND CSV. NUMERIC DATA DOES SHOW
SOME REDUCTION OF VSBYS DUE TO FOG POTENTIAL AS WELL. EXPECTED
DEWPOINT DEPRESSIONS WILL BE 2 DEGREES OR LESS BY 12Z. THUS...WILL
OPT TO INCLUDE SOME LATE NIGHT PATCHY FOG ACROSS THE AREA.
OTW...ISOL LIGHT CONVECTION CONTINUES THIS AFTERNOON ACROSS EASTERN
AREAS. ANOTHER AREA OF CONVECTION IS NOT REALLY ATTEMPTING TO
ADVANCE OUR WAY FROM WESTERN KY. THIS IS IN ADVANCE OF AN
APPROACHING COLD FRONT WHICH SHOULD REACH OUR AREA TOMORROW
MORNING AFTER SUNRISE. HRRR PICKS UP ON THE AFOREMENTIONED
CONVECTION TO OUR NORTHWEST BUT DOES LITTLE IN THE WAY TO BRING
THAT ACTIVITY ACROSS OUR AREA. TURNS OUT...THE UPPER LEVEL
DYNAMICS OVERNIGHT TONIGHT LOOK WEAK. SO EVEN THOUGH THE FRONT
WILL REACH OUR NORTHWESTERN COUNTIES AROUND SUNRISE...THERE MAY
NOT BE MUCH ACTIVITY. SO...FOR TONIGHT`S FCST...WILL INCLUDE JUST
20 PERCENT POPS...PERHAPS A LITTLE HIGHER PLATEAU IF LATEST RADAR
TRENDS LEAN TOWARD CONVECTIVE EXPANSION.
ON SATURDAY...COLD FRONT WILL MOVE SOUTH OF THE AREA BUT THE
WESTERLIES ALOFT WILL BEGIN TO GAIN SOME STRENGTH. WITHIN THAT
WESTERLY FLOW...A SERIES OF DISTURBANCES WILL CROSS THE AREA AND
BRING A BETTER CHANCE...40% OR SO...OF SHOWERS. SHOWALTER VALUES ARE
NEGATIVE WITH DESCENT CAPE BY AFTERNOON. THEREFORE...WILL OPT TO
INCLUDE THUNDER STORM POTENTIAL AS WELL.
BY SATURDAY NIGHT...THE FRONT WILL BE WELL SOUTH OF THE AREA WITH
850 MB FLOW NORTHERLY AS WELL. UPPER LEVEL WESTERLIES NOW LEANING
TOWARD MORE OF AN NVA REGIME AND HENCE...POPS WILL NOT BE INCLUDED.
ACROSS THE PLATEAU HOWEVER...ELEVATED MOISTURE LEVELS WILL HANG ON
JUST A BUT LONGER SO I MAY INCLUDE JUST A 20 POP. THAT 20 POP WILL
CONTINUE INTO SUNDAY AS WELL.
FOR THE NEAR TERM TEMPS...NOT TOO MUCH DEVIATION VERSUS THE MODEL
GUIDANCE. WILL GO JUST A TOUCH HIGHER ON THE MONDAY MORNING LOWS.
IN THE EXTENDED FCST...THE WESTERLIES WILL CONTINUE BUT WILL BE
RATHER UNEVENTFUL MONDAY AND TUESDAY. BUT...ON THURSDAY...ANOTHER
COLD FRONT WILL REACH OUR AREA. THIS ONE LOOKS A BIT STRONGER WITH
COOLER AIR IN ITS WAKE. COULD BE A DESCENT RAIN PRODUCER AND THERE
COULD BE ENOUGH INSTABILITY ON BOTH WEDNESDAY AND THURSDAY
AFTERNOONS SO AS TO PRODUCE A FEW STRONG STORMS. OTW...FOR
NOW...MODELS LEAN TOWARD A DRIER AND COOLER FRIDAY OF NEXT WEEK
BEHIND THE FROPA.
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 71 88 68 83 / 20 50 20 10
CLARKSVILLE 68 85 63 81 / 20 50 10 10
CROSSVILLE 65 84 66 79 / 20 50 30 20
COLUMBIA 70 89 68 84 / 20 50 20 10
LAWRENCEBURG 68 89 67 85 / 20 50 20 20
WAVERLY 69 86 64 82 / 20 50 20 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
920 PM CDT SAT SEP 6 2014
.UPDATE...
SEE DISCUSSION FOR EVENING UPDATE.
&&
.DISCUSSION...
PERSISTENT SHOWERS AND THUNDERSTORMS NEAR COLLEGE STATION HAVE
FINALLY COME TO AN END THIS EVENING. THE SHOWERS AND THUNDERSTORMS
SEEM TO HAVE FORMED ALONG A PRE FRONTAL TROUGH. MODELS HAVE REALLY
STRUGGLED THIS EVENING ON THE EVOLUTION OF PRECIP OVERNIGHT. THERE
IS PRECIP CURRENTLY JUST NORTH OF HOUSTON COUNTY THAT IS
FORECASTED TO MOVE SOUTH OVERNIGHT ALONG WITH THE WIND SHIFT. THE
PRE FRONTAL TROUGH IS FORECASTED TO MAKE IT TO THE INTERSTATE 10
BEFORE STALLING TOMORROW AFTERNOON. FORECAST SOUNDINGS SHOW AMPLE
MOISTURE TOMORROW AFTERNOON (NEAR 2.00" PWATS) AND INSTABILITY.
HAVE RAISED POPS OVERNIGHT TO ACCOUNT FOR RAIN NORTH OF HOUSTON
COUNTY SINKING SOUTH. 23
&&
.PREV DISCUSSION... /ISSUED 632 PM CDT SAT SEP 6 2014/
DISCUSSION...
SEE 00Z AVIATION DISCUSSION.
AVIATION...
A PRE-FRONTAL TROUGH EXTENDED FROM SHREVEPORT TO JUNCTION WITH A
COLD FRONT EXTENDING FROM ABOUT PARIS TO SAN ANGELO TO FORT
STOCKTON. THE FRONT WILL SLOWLY PUSH ACROSS SE TX OVERNIGHT.
MODELS ARE ALL OVER THE PLACE WITH REGARD TO ADDITIONAL SHRA/TSRA
DEVELOPMENT OVERNIGHT. THE HRRR DID NOT INITIALIZE WELL...THE RAP
LOOKS OVERDONE AND GUIDANCE JUST DOESN`T SEEM TO HAVE A HANDLE ON
CONVECTIVE TRENDS. MESO-SCALE INFLUENCES WILL PROBABLY DETERMINE
WHEN/WHERE SHRA DEVELOP LATER TONIGHT. WILL LIKELY BE AMENDING
LATER TONIGHT IF/WHEN CONVECTIVE TRENDS CAN BE ESTABLISHED. 43
PREV DISCUSSION... /ISSUED 334 PM CDT SAT SEP 6 2014/
DISCUSSION...
SCT PCPN ASSOCIATED WITH THE UPPER LOW JUST OFFSHORE WILL LIKELY
DISSIPATED SHORTLY AFTER SUNSET LATER THIS EVENING. HOWEVER RAIN
CHANCES TO CONTINUE AS A FRONTAL BOUNDARY APPROACHES FROM THE
NORTH OVERNIGHT. THE COMBINATION OF THIS SFC BOUNDARY...LINGERING
GULF MOISTURE...PROXIMITY OF THE UPPER LOW AND DAYTIME HEATING
SHOULD HELP KEEP SOME PRETTY ROBUST POPS FOR SE TX THESE NEXT FEW
DAYS. THE FRONT EXPECTED TO WASH OUT LATE MON AS THE UPPER RIDGE
TRIES TO REBUILD OVER THE REGION ALSO AROUND THAT SAME TIME. THIS
WILL ALLOW FOR WARM/HUMID/GENERALLY NO POP WX FOR TUES/WEDS.
POPS PROGGED TO RETURN BY THURS ON INTO THE END OF THE WEEK WITH
THE APPROACH/PASSAGE OF ANOTHER FRONTAL BOUNDARY. MODELS SEEM TO
BE IN SLIGHTLY BETTER AGREEMENT WITH A LATE THUR/EARLY FRI FROPA
ALONG WITH COOLER TEMPS/INCREASED POPS. 41
MARINE...
SFC FRONT WILL PUSH INTO SE TX TONIGHT INTO TOMORROW BUT STALL
BEFORE REACHING THE COAST. THIS WILL ALLOW FOR LIGHT/VARIABLE
WINDS FOR THE OFFSHORE WATERS. THUNDERSTORM ACTIVITY WILL CONTINUE
DUE TO AN UPPER LEVEL LOW PRESSURE SYSTEM AND THE FRONTAL BOUNDARY
PUSHING TOWARDS THE COAST. THUNDERSTORM CHANCES SHOULD DECREASE
MONDAY INTO TUESDAY. SOUTHERLY WINDS FINALLY INCREASE MID WEEK
AND CONTINUE THROUGH THE END OF NEXT WEEK. FORECAST MODELS
CONTINUE TO SHOW A STRONGER FRONT PUSHING OFF THE COAST NEXT
FRI/SAT.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 93 74 95 75 / 50 50 40 30 20
HOUSTON (IAH) 75 91 74 93 75 / 40 50 40 30 20
GALVESTON (GLS) 77 89 78 91 80 / 20 40 30 30 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...23
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
632 PM CDT SAT SEP 6 2014
.DISCUSSION...
SEE 00Z AVIATION DISCUSSION.
&&
.AVIATION...
A PRE-FRONTAL TROUGH EXTENDED FROM SHREVEPORT TO JUNCTION WITH A
COLD FRONT EXTENDING FROM ABOUT PARIS TO SAN ANGELO TO FORT
STOCKTON. THE FRONT WILL SLOWLY PUSH ACROSS SE TX OVERNIGHT.
MODELS ARE ALL OVER THE PLACE WITH REGARD TO ADDITIONAL SHRA/TSRA
DEVELOPMENT OVERNIGHT. THE HRRR DID NOT INITIALIZE WELL...THE RAP
LOOKS OVERDONE AND GUIDANCE JUST DOESN`T SEEM TO HAVE A HANDLE ON
CONVECTIVE TRENDS. MESO-SCALE INFLUENCES WILL PROBABLY DETERMINE
WHEN/WHERE SHRA DEVELOP LATER TONIGHT. WILL LIKELY BE AMENDING
LATER TONIGHT IF/WHEN CONVECTIVE TRENDS CAN BE ESTABLISHED. 43
&&
.PREV DISCUSSION... /ISSUED 334 PM CDT SAT SEP 6 2014/
DISCUSSION...
SCT PCPN ASSOCIATED WITH THE UPPER LOW JUST OFFSHORE WILL LIKELY
DISSIPATED SHORTLY AFTER SUNSET LATER THIS EVENING. HOWEVER RAIN
CHANCES TO CONTINUE AS A FRONTAL BOUNDARY APPROACHES FROM THE
NORTH OVERNIGHT. THE COMBINATION OF THIS SFC BOUNDARY...LINGERING
GULF MOISTURE...PROXIMITY OF THE UPPER LOW AND DAYTIME HEATING
SHOULD HELP KEEP SOME PRETTY ROBUST POPS FOR SE TX THESE NEXT FEW
DAYS. THE FRONT EXPECTED TO WASH OUT LATE MON AS THE UPPER RIDGE
TRIES TO REBUILD OVER THE REGION ALSO AROUND THAT SAME TIME. THIS
WILL ALLOW FOR WARM/HUMID/GENERALLY NO POP WX FOR TUES/WEDS.
POPS PROGGED TO RETURN BY THURS ON INTO THE END OF THE WEEK WITH
THE APPROACH/PASSAGE OF ANOTHER FRONTAL BOUNDARY. MODELS SEEM TO
BE IN SLIGHTLY BETTER AGREEMENT WITH A LATE THUR/EARLY FRI FROPA
ALONG WITH COOLER TEMPS/INCREASED POPS. 41
MARINE...
SFC FRONT WILL PUSH INTO SE TX TONIGHT INTO TOMORROW BUT STALL
BEFORE REACHING THE COAST. THIS WILL ALLOW FOR LIGHT/VARIABLE
WINDS FOR THE OFFSHORE WATERS. THUNDERSTORM ACTIVITY WILL CONTINUE
DUE TO AN UPPER LEVEL LOW PRESSURE SYSTEM AND THE FRONTAL BOUNDARY
PUSHING TOWARDS THE COAST. THUNDERSTORM CHANCES SHOULD DECREASE
MONDAY INTO TUESDAY. SOUTHERLY WINDS FINALLY INCREASE MID WEEK
AND CONTINUE THROUGH THE END OF NEXT WEEK. FORECAST MODELS
CONTINUE TO SHOW A STRONGER FRONT PUSHING OFF THE COAST NEXT
FRI/SAT.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 94 74 95 75 / 40 50 40 30 20
HOUSTON (IAH) 75 93 74 93 75 / 40 50 40 30 20
GALVESTON (GLS) 80 89 78 91 80 / 20 40 30 30 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...23
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1254 PM CDT FRI SEP 5 2014
.AVIATION...
EXPECT TO SEE SIMILAR CONDITIONS THAT WE`VE SEEN FOR THE PAST
SEVERAL DAYS. PRIMARILY VFR OUTSIDE ANY SCT CONVECTION. PRECIP
TRENDS ALSO ABOUT THE SAME...SCT ACTIVITY DEVELOPING NEAR/OFF
COAST IN EARLY MORNING THEN TRANSITIONING INLAND LATE MORNING AND
AFTERNOON WITH DAYTIME HEATING. PRECIP TAPERS OFF IN THE EARLY
EVENING WITH LOSS OF HEATING. 47
&&
.PREV DISCUSSION... /ISSUED 1030 AM CDT FRI SEP 5 2014/
AN UPPER AIR ANALYSIS SHOWED A HIGH PRESSURE RIDGE EXTENDING FROM
THE MID ATLANTIC INTO THE LOWER TEXAS COAST. THE WATER VAPOR ALSO
SHOWED AN UPPER LOW OVER SOUTHERN LA DRIFTING WESTWARD..ALTHOUGH
THERE WAS ANOTHER UPPER LEVEL HIGH PRESSURE AREA OVER AR DRIFTING
SOUTHWESTWARD. THE 12Z SOUNDINGS SHOWED AN UNCAPPED AIRMASS WITH
PW/S FROM 1.8 TO 2 INCHES...ALTHOUGH DRIER AIR ASSOCIATED WITH THE
HIGH OVER AR WAS WORKING ITS WAY INTO THE AREA FROM THE NORTHEAST.
THIS SHOULD BE OFFSET LATER TODAY BY THE MOIST AIRMASS OVER
SOUTHERN LA WORKING ITS WAY WESTWARD. CAPE VALUES AT KLCH AND KCRP
RANGED FROM 3000 TO 3500...WHILE THE DRIER AIRMASS AT KSHV HAD A
CAPE OF 1600. ISOLATED STRONG STORMS ARE POSSIBLE WITH THE MAIN
THREAT STRONG WINDS AND LOCALLY HEAVY DOWNPOURS. OF THE HIGH
RESOLUTION MODELS...THE ARW INITIALIZED FAIRLY WELL. A CONSENSUS
OF THE ARW AND HRRR INDICATES SCATTERED COVERAGE OVER MOST OF THE
INLAND AREAS LATER TODAY.
TWEAKED THE RAIN CHANCES AND HUMIDITY GRIDS TODAY. ALSO UPDATED
THE HAZARDOUS WEATHER OUTLOOK TO INCLUDE THE POTENTIAL FOR
ISOLATED STRONG STORMS TODAY...SATURDAY...AND SUNDAY. 40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 95 74 95 74 94 / 30 10 40 20 30
HOUSTON (IAH) 93 75 92 75 93 / 30 10 40 20 30
GALVESTON (GLS) 90 81 90 80 89 / 40 10 30 20 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1030 AM CDT FRI SEP 5 2014
.DISCUSSION...
AN UPPER AIR ANALYSIS SHOWED A HIGH PRESSURE RIDGE EXTENDING FROM
THE MID ATLANTIC INTO THE LOWER TEXAS COAST. THE WATER VAPOR ALSO
SHOWED AN UPPER LOW OVER SOUTHERN LA DRIFTING WESTWARD..ALTHOUGH
THERE WAS ANOTHER UPPER LEVEL HIGH PRESSURE AREA OVER AR DRIFTING
SOUTHWESTWARD. THE 12Z SOUNDINGS SHOWED AN UNCAPPED AIRMASS WITH
PW/S FROM 1.8 TO 2 INCHES...ALTHOUGH DRIER AIR ASSOCIATED WITH
THE HIGH OVER AR WAS WORKING ITS WAY INTO THE AREA FROM THE
NORTHEAST. THIS SHOULD BE OFFSET LATER TODAY BY THE MOIST AIRMASS
OVER SOUTHERN LA WORKING ITS WAY WESTWARD. CAPE VALUES AT KLCH AND
KCRP RANGED FROM 3000 TO 3500...WHILE THE DRIER AIRMASS AT KSHV
HAD A CAPE OF 1600. ISOLATED STRONG STORMS ARE POSSIBLE WITH THE
MAIN THREAT STRONG WINDS AND LOCALLY HEAVY DOWNPOURS. OF THE HIGH
RESOLUTION MODELS...THE ARW INITIALIZED FAIRLY WELL. A CONSENSUS
OF THE ARW AND HRRR INDICATES SCATTERED COVERAGE OVER MOST OF THE
INLAND AREAS LATER TODAY.
TWEAKED THE RAIN CHANCES AND HUMIDITY GRIDS TODAY. ALSO UPDATED
THE HAZARDOUS WEATHER OUTLOOK TO INCLUDE THE POTENTIAL FOR
ISOLATED STRONG STORMS TODAY...SATURDAY...AND SUNDAY.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 95 74 95 74 94 / 30 10 40 20 30
HOUSTON (IAH) 93 75 92 75 93 / 30 10 40 20 30
GALVESTON (GLS) 90 81 90 80 89 / 40 10 30 20 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...47
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
353 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 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1220 PM CDT FRI SEP 5 2014
WEAK SHORTWAVE TROUGH EXITING EAST...BUT ANOTHER WILL MOVE IN FROM
THE CENTRAL PLAINS LATER THIS AFTERNOON. THIS FEATURE IS ALREADY
FIRING SHRA/TS OVER NEB...AND THIS ACTIVITY SHOULD SPREAD INTO PARTS
OF NORTHEAST IA/SOUTHWEST WI TOWARD 21Z...WITH MESO MODELS EXITING
IT ENE BY 02Z. ALL FAVORING KEEPING THIS ACTIVITY SOUTH OF KRST/KLSE
FOR NOW...BUT COULD SEE SOME RW-- ASSOCIATED WITH A FRONTOGENETIC
REGION. WILL ADD IN SOME VCSH FOR NOW.
SOME LOWER MVFR CIGS HAVE DEVELOPED IN THAT FRONTOGENETIC REGION
NORTH OF THE APPROACHING SHORTWAVE. THESE LOWER CIGS WILL LIKELY
STICK AROUND FOR THE BETTER PART OF THE AFTERNOON...ALTHOUGH SOME
DIURNAL BUMP UPWARD IS PROBABLE. THESE LOWER CLOUDS WILL EXIT LATER
THIS AFTERNOON-EARLY EVENING...WITH SKC-VFR LATER THIS EVENING INTO
FRIDAY.
AS FOR VALLEY FOG AT KLSE...BUFKIT SOUNDINGS VIA THE NAM AND RAP
KEEP A T/TD SPREAD THROUGH THE NIGHT...AND WINDS OF 10+ KTS BLOWING
BY 200 FT. POTENTIAL FOR VSBY RESTRICTIONS AT KLSE FROM FG LOOKS LOW
AS A RESULT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
338 PM CDT FRI SEP 5 2014
.TONIGHT AND SATURDAY...FORECAST CONFIDENCE IS HIGH.
CONVECTION ASSOCIATED WITH SURFACE COLD FRONT PUSHED THROUGH KENOSHA
COUNTY IN THE PAST HOUR...AND IS NOW MOVING AWAY FROM THAT AREA.
AREA OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUES TO PUSH
NORTHEAST INTO THE AREA FROM EASTERN IOWA AND FAR NORTHWEST
ILLINOIS. THIS IS ASSOCIATED WITH LOW LEVEL FRONTOGENESIS RESPONSE
FIELDS AND UPPER DIVERGENCE FROM RIGHT REAR QUADRANT OF 250 MB JET
STREAK.
THESE FEATURES SHOULD SLIDE ACROSS A GOOD PORTION OF THE AREA INTO
EARLY THIS EVENING. SO...BROUGHT IN HIGHER POPS FOR SHOWERS AND
ISOLATED STORMS ACROSS A GOOD PORTION OF THE AREA. THIS IS SUPPORTED
BY LATEST HRRR RUN AND WRF NMM/ARW MODELS. WENT WITH MORE SCATTERED
TO NUMEROUS SHOWER WORDING...AS THEY WILL HAVE TO BATTLE DRYING LOW
LEVEL AIR ACROSS THE AREA.
PRECIPITATION SHOULD EXIT THE AREA BY MIDDLE EVENING...WITH SKIES
BECOMING MOSTLY CLEAR FROM WEST TO EAST LATER TONIGHT INTO SATURDAY
MORNING. HIGH PRESSURE SLIDING EAST TOWARD THE REGION WILL BRING
QUIET WEATHER INTO SATURDAY. LOWS TONIGHT SHOULD DROP INTO THE LOWER
50S INLAND...WITH MILDER READINGS NEAR THE LAKE. HIGHS SHOULD REACH
THE LOWER 70S ON SATURDAY.
.SATURDAY NIGHT THROUGH MONDAY - CONFIDENCE HIGH...
ALL MODELS SHOW HIGH PRESSURE CENTERED OVER THE CENTRAL PLAINS
SATURDAY NIGHT EXPANDING OVER THE GREAT LAKES SUNDAY AND CONTINUE TO
BUILD NORTHEASTWARD THROUGH MONDAY. THIS WILL BRING MOSTLY CLEAR
SKIES..LIGHT WINDS...DRIER CONDITIONS. HIGH TEMPERATURES NEAR
NORMAL...IN THE MID 70S. GOOD RADIATIONAL COOLING CONDITIONS WILL
ALLOW OVERNIGHT LOW TEMPERATURES TO DROP SLIGHTLY BELOW NORMAL...LOW
50S.
.MONDAY NIGHT THROUGH THURSDAY - CONFIDENCE...MEDIUM
LOW PRESSURE DEVELOPING WEST THE AREA MONDAY NIGHT AND APPROACHING
THE REGION TUESDAY CREATES A SOUTHWESTERLY FLOW AND SIGNIFICANT
MOISTURE ADVECTION WITH CHANCE OF SHOWERS DEVELOPING MONDAY NIGHT
AND INCREASING TUESDAY. SURFACE LOW PRESSURE DEEPENING OVER THE AREA
TUESDAY NIGHT AND SLOWLY MOVING NORTHEASWARD AND DEEPENING ACROSS
THE GREAT LAKES REGION THROUGH THURSDAY. THIS LOW COMBINED WITH
MULTIPLE UPPER LEVEL SHORT WAVES SHOULD KEEP UNSETTLED WEATHER AND A
CHANCE OF RAINSHOWERS AND SOME THUNDERSTORMS THROUGHOUT THE MIDDLE
OF NEXT WEEK.
.THURSDAY NIGHT AND FRIDAY - CONFIDENCE...MEDIUM
STRONG HIGH PRESSURE EXPECTED TO DEVELOP OVER THE CENTRAL AND
NORTHERN PLAINS AND LOW PRESSURE CENTER REMAINING OVER SOUTHEAST
CANADA WILL PRODUCE NORTHWEST FLOW ACROSS WISCONSIN. THIS WILL BRING
DRIER BUT SIGNIFICANTLY COOLER AIR TO THE AREA FRIDAY AND INTO THE
WEEKEND. THURSDAY NIGHT LOWS IN THE 40S. HIGH TEMPERATURES FRIDAY
MAY STRUGGLE TO REACH 60.
&&
.AVIATION/00Z TAFS/...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED UNTIL
AROUND 03Z SATURDAY ACROSS TAF SITES...AS A TROUGH OF LOW PRESSURE
MOVES THROUGH THE REGION. CEILINGS SHOULD BECOME VFR CATEGORY DURING
THIS TIME. MODERATE NORTHWEST WINDS WITH SOME GUSTS TO AROUND 15
KNOTS WILL LINGER UNTIL AROUND 00Z SATURDAY.
HIGH PRESSURE MOVING EAST TOWARD THE REGION LATER TONIGHT INTO
SATURDAY WILL BRING QUIET WEATHER TO THE AREA. SKIES SHOULD BECOME
MOSTLY CLEAR BY LATER TONIGHT OR EARLY SATURDAY. WINDS WILL BECOME
LIGHT OUT OF THE NORTH TO NORTHWEST DURING THIS TIME.
&&
.MARINE...
NORTHWEST WINDS OF 10 TO 15 KNOTS WILL LINGER UNTIL AROUND 00Z
SATURDAY. MAY SEE A FEW GUSTS TO 20 KNOTS. WINDS WILL DIMINISH
TONIGHT WITH WEAKENING PRESSURE GRADIENT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/SATURDAY AND AVIATION/MARINE...WOOD
SATURDAY NIGHT THROUGH FRIDAY...SLB
AREA FORECAST DISCUSSION...CORRECTED AVIATION
NWS LA CROSSE WI
1220 PM CDT FRI SEP 5 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT FRI SEP 5 2014
THE MAIN FOCUS IN THE SHORT TERM IS ON THE PRECIPITATION/TEMPERATURE/DEW
POINT TRENDS AS A COLD FRONT MOVES THROUGH THE REGION.
CURRENTLY...A SURFACE COLD FRONT EXTENDS FROM THE WESTERN UP OF
MICHIGAN DOWN THROUGH SOUTHWEST WISCONSIN AND SOUTH CENTRAL IOWA.
THE AIR MASS BEHIND THIS FRONT IS MUCH COOLER AND LESS HUMID WITH
TEMPERATURES DROPPING FROM THE UPPER 70S TO THE MID 50S AND DEW
POINTS GOING FROM THE MID 70S TO THE UPPER 40S. WHILE THE
ENVIRONMENT IN THE WARM SECTOR IS CAPPED OFF...SOME SLOPING LOW
LEVEL FRONTOGENESIS IS BEING AIDED BY A MID LEVEL TROUGH DIGGING
ACROSS NORTH DAKOTA/NORTHERN MINNESOTA AND HAS PRODUCED A BAND OF
CONVECTION ACROSS THE NORTHERN HALF OF IOWA. THIS RAIN WILL TRACK
TO THE NORTHEAST/EAST THIS MORNING BUT LIKELY WEAKEN AS IT LEAVES
THE DEEPER FORCING IN CENTRAL IOWA. THE 05.07Z RAP SHOWS THAT THE
0-3KM MUCAPE DROPS QUITE A BIT ONCE YOU REACH THIS
PRECIPITATION AND VERTICAL SHEAR PROFILES SHOW ONLY ABOUT 20-30KTS
OF 0-6KM SHEAR WITH MUCH OF IT AROUND 900-750MB. BASED ON
THIS...AM NOT EXPECTING MUCH IN THE WAY OF SEVERE WEATHER BUT
THAT THERE WILL BE A PERIOD OF LIGHT TO MODERATE
RAINFALL...PARTICULARLY ACROSS NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN.
CLOUD COVER WILL LIKELY LINGER THROUGH MUCH OF THE DAY AS ANOTHER
MID LEVEL SHORT WAVE TROUGH TRACKS TO THE EAST FROM EASTERN
COLORADO/WESTERN NEBRASKA ON THROUGH IOWA TODAY. 06.00Z NAM/GFS
FORECAST SOUNDINGS SHOW A SATURATING MID LEVEL LAYER WITH DRY AIR
STUCK UNDERNEATH IT. WHILE THE FOCUS APPEARS TO MAINLY BE ACROSS
THE SOUTHERN HALF OF IOWA INTO TONIGHT...THE 05.00Z NAM/GFS/ECMWF
DO HINT AT SOME LIGHT QPF MAKING IT INTO THE REGION. CONFIDENCE IS
NOT HIGH ENOUGH RIGHT NOW WITH WHAT WILL WIN OUT IN THIS BATTLE OF
DRY AIR...SO HAVE KEPT THE FORECAST DRY INTO TONIGHT FOR THE TIME
BEING.
OTHERWISE...HIGH TEMPERATURES HAVE ALREADY BEEN HIT FOR THE DAY AS
THEY WILL DROP INTO THIS MORNING AND THEN MAKE A SMALL DIURNAL
BUMP THIS AFTERNOON BEFORE DROPPING QUICKLY TONIGHT. LOW LEVEL
WINDS LOOK LIKE THEY SHOULD BE STRONG ENOUGH TO KEEP ANY VALLEY
FOG FROM FORMING...BUT WILL HAVE TO MONITOR THE CONDITIONS INTO
TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 AM CDT FRI SEP 5 2014
FAIRLY QUIET EXTENDED PERIOD WITH THE COOLER TEMPERATURES THE MAIN
STORY. THE COOLEST PERIOD APPEARS TO BE THIS WEEKEND AS +6C TO +8C
850MB AIR SITS OVER THE REGION BEFORE WARMER AIR GETS ADVECTED IN
ON THE BACK SIDE OF THE RIDGE EARLY NEXT WEEK. THE NEXT CHANCES
FOR PRECIPITATION ARE ON MONDAY INTO THURSDAY AS A MID LEVEL
SHORT WAVE TROUGH MOVES THROUGH THE REGION. NOT MUCH INSTABILITY
TO WORK WITH AS THE 05.00Z GFS/ECMWF SHOW LESS THAN 1000 J/KG OF
0-3KM MUCAPE AROUND THE REGION SO DO NOT EXPECT MUCH IN THE WAY
OF WIDESPREAD THUNDERSTORMS...PARTICULARLY ANYTHING CONSIDERED
SEVERE.
A MORE SIGNIFICANT COLD PUSH LOOKS LIKE IT WILL MOVE IN ON
THURSDAY WITH 850MB TEMPERATURES DROPPING BELOW 0C. THIS WILL
LIKELY LEAD TO SOME LOW TEMPERATURES DIPPING INTO THE 30S GOING
INTO FRIDAY MORNING AND THE POTENTIAL FOR SOME FROST IN THE
TYPICAL LOW/COLD BOG AREAS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1220 PM CDT FRI SEP 5 2014
WEAK SHORTWAVE TROUGH EXITING EAST...BUT ANOTHER WILL MOVE IN FROM
THE CENTRAL PLAINS LATER THIS AFTERNOON. THIS FEATURE IS ALREADY
FIRING SHRA/TS OVER NEB...AND THIS ACTIVITY SHOULD SPREAD INTO PARTS
OF NORTHEAST IA/SOUTHWEST WI TOWARD 21Z...WITH MESO MODELS EXITING
IT ENE BY 02Z. ALL FAVORING KEEPING THIS ACTIVITY SOUTH OF KRST/KLSE
FOR NOW...BUT COULD SEE SOME RW-- ASSOCIATED WITH A FRONTOGENETIC
REGION. WILL ADD IN SOME VCSH FOR NOW.
SOME LOWER MVFR CIGS HAVE DEVELOPED IN THAT FRONTOGENETIC REGION
NORTH OF THE APPROACHING SHORTWAVE. THESE LOWER CIGS WILL LIKELY
STICK AROUND FOR THE BETTER PART OF THE AFTERNOON...ALTHOUGH SOME
DIURNAL BUMP UPWARD IS PROBABLE. THESE LOWER CLOUDS WILL EXIT LATER
THIS AFTERNOON-EARLY EVENING...WITH SKC-VFR LATER THIS EVENING INTO
FRIDAY.
AS FOR VALLEY FOG AT KLSE...BUFKIT SOUNDINGS VIA THE NAM AND RAP
KEEP A T/TD SPREAD THROUGH THE NIGHT...AND WINDS OF 10+ KTS BLOWING
BY 200 FT. POTENTIAL FOR VSBY RESTRICTIONS AT KLSE FROM FG LOOKS LOW
AS A RESULT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION.....RIECK
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1129 AM CDT FRI SEP 5 2014
.UPDATE...
COLD FRONT SLIDING THROUGH THE FAR SOUTHEAST COUNTIES...AND WILL
EXIT THE AREA EARLY THIS AFTERNOON. SOME LIGHT SHOWERS MAY AFFECT
PARTS OF SOUTH CENTRAL WISCONSIN OVER THE NEXT HOUR OR TWO...AS
500 MB VORTICITY MAXIMUM SHIFTS THROUGH WISCONSIN. THEY WERE
SHOWING A DECREASING TREND...AS THEY MOVE INTO AN AREA OF COLD AIR
ADVECTION WITH DRIER LOW LEVEL AIR.
OTHER LIGHT SHOWERS ARE POSSIBLE THROUGH THE AFTERNOON...WITH LOW
LEVEL FRONTOGENESIS RESPONSE FIELDS AND UPPER DIVERGENCE FROM
RIGHT REAR QUADRANT OF 250 MB JET STREAK. THE SOUTHEAST COUNTIES
WOULD HAVE THE BEST CHANCES...THOUGH MAY SEE MORE MOVE TOWARD THE
WESTERN COUNTIES LATER IN THE AFTERNOON WITH INCREASING UPPER
DIVERGENCE. FOR NOW...KEPT POPS GOING IN THE SOUTHEAST AND FAR
SOUTHERN COUNTIES...AND DRY ELSEWHERE THIS AFTERNOON.
SHOWERS WILL HAVE TO BATTLE DRYING LOW LEVEL AIR ACROSS THE
AREA...SO SOME UNCERTAINTY WITH AREAL COVERAGE. MEAN LAYER CAPES
SHIFTING SOUTHEAST OF THE AREA WITH COLD FRONT. AREA FORECAST
SOUNDINGS SHOWING ELEVATED CAPE WEAKENING DURING THE
AFTERNOON...SO WENT WITH ISOLATED THUNDER WORDING.
SHOULD SEE SOME CUMULUS DEVELOPMENT THIS AFTERNOON WHICH WOULD
FILL IN CLOUD FREE AREAS. TEMPERATURES SHOULD REACH THE MID 70S
ACROSS MOST OF THE AREA...WITH LOWER 80S LINGERING IN THE FAR
SOUTHEAST.
&&
.AVIATION/18Z TAFS/...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE THROUGH
THE AFTERNOON AND EVENING HOURS...AS A TROUGH OF LOW PRESSURE
MOVES THROUGH THE REGION. CEILINGS SHOULD BECOME VFR CATEGORY WITH
DIRUNAL CUMULUS AND MIDDLE LEVEL CLOUDS EXPECTED. MODERATE WEST
WINDS WILL VEER NORTHWEST AS WELL...WITH SOME GUSTS UP TO 18
KNOTS.
HIGH PRESSURE MOVING EAST TOWARD THE REGION TONIGHT INTO SATURDAY
WILL BRING QUIET WEATHER TO THE AREA. SKIES SHOULD BECOME MOSTLY
CLEAR BY LATER TONIGHT. MAY SEE SOME DIURNAL CUMULUS ON SATURDAY.
WINDS WILL BECOME LIGHT OUT OF THE NORTH TO NORTHWEST DURING THIS
TIME.
&&
.MARINE...
WEST WINDS OF 10 TO 15 KNOTS WILL VEER NORTHWEST BY EARLY THIS
AFTERNOON. MAY SEE A FEW GUSTS TO 20 KNOTS. WINDS WILL DIMINISH
TONIGHT WITH WEAKENING PRESSURE GRADIENT.
&&
.PREV DISCUSSION... /ISSUED 305 AM CDT FRI SEP 5 2014/
TODAY...FORECAST CONFIDENCE IS MEDIUM.
THE MAIN ISSUE FOR TODAY IS THE ARRIVAL OF A STRONG COLD FRONT EARLY
THIS MORNING...EXITING EAST OF MILWAUKEE BY LATE MORNING. AN AREA
OF WEAKENING CONVECTION OVER IOWA EARLY THIS MORNING IS BEING PICKED
UP BY THE HRRR AND TRACKED ACROSS THE FORECAST AREA THIS
MORNING...MOSTLY BEFORE 8 AM. THE HRRR ALSO SUGGESTS INTENSIFICATION
AND EXPANSION. THIS ACTIVITY IS FOCUSED ALONG THE H8 COLD
FRONT...WHICH IS POST FRONTAL OF THE SFC FRONT. THE CONCERN IS IT
MAY CATCH UP WITH THE SFC FRONT OVER OUR WRN CWA THIS MORNING AND
BECOME MORE SFC BASED. INSTABILITY IS PRETTY HIGH ACROSS THE AREA
RIGHT NOW...SO WILL HAVE TO WATCH TRENDS VERY CLOSELY. THERE IS A
DISTINCT LACK OF MID AND UPPER LEVEL SUPPORT AND DEEP LAYER SHEAR IS
RATHER WEAK. WILL HANG ONTO A CHANCE FOR STORMS UNTIL THE FRONT
EXITS.
THEN SOME MID LEVEL FORCING FROM AN APPROACHING SHORT WAVE COULD
RESULT IN SOME INCREASING SHOWERS SHOWERS AND ISOLATED THUNDERSTORMS
ACROSS THE SOUTHEAST THIS AFTERNOON AND INTO THE EVENING HOURS. THIS
WILL ALL BE POST FRONTAL WITH A DECENT RIGHT REAR UPPER JET QUADRANT
HELPING TO SUPPORT DECENT 700-600MB FRONTOGENESIS. THE MAIN
QUESTION IS WHETHER THERE/LL BE ENOUGH DEEP MOISTURE LEFT TO SUPPORT
SHOWERS. SOME OF THE MODELS SCOUR OUT THE RAIN ONCE THE FRONT
EXITS...OTHERS DO THE POST FRONTAL GIG...SO WILL HANG ONTO POPS SE.
COOLER AND DRIER AIR WILL CONTINUE TO OVERSPREAD THE AREA AS THE DAY
PROGRESSES.
TONIGHT...FORECAST CONFIDENCE IS HIGH.
OTHER THAN SOME LINGERING EVENING SHOWERS POSSIBLE IN THE
SOUTHEAST...THE COOLER...DRIER TREND WILL CONTINUE. SKIES WILL
GRADUALLY CLEAR WITH LOWS DIPPING INTO THE LOWER 50S OVER ALL BUT
THE SOUTHEAST. THE CLOUDS CLEARING LATER ACROSS THE SOUTHEAST WILL
KEEP TEMPS UP A BIT HIGHER.
SATURDAY AND SUNDAY - CONFIDENCE...MEDIUM
HIGH PRESSURE IN THE CENTRAL PLAINS SATURDAY WILL EXPAND ACROSS THE
GREAT LAKES SUNDAY. NORTHWEST WINDS AND THERMAL TROUGH LINGERS THROUGH
SATURDAY EVENING. SUBTLE MODIFICATION FOR SUNDAY AS 850 TEMPS MODIFY
ONLY SLIGHTLY. LIGHT WIND REGIME WITH SURFACE HIGH WELL IN PLACE AND
GRADIENT WEAK.
MONDAY - CONFIDENCE...MEDIUM
MODELS SHOW 500 MILLIBAR TROUGH APPROACHING INTO IA/MN BY END OF THE
DAY. 850 JET AXIS REMAINS WEST AND LIKE THE DRY LOOK FOR SRN WI.
WITH HIGH TO THE EAST THE FLOW WILL BECOME DECIDEDLY FROM THE
SOUTH...SO GRADUAL MOISTURE ADVECTION THOUGH BEST PUSH OF THIS HOLDS
OFF TO OUR WEST DURING THE DAY.
MONDAY NIGHT AND TUESDAY - CONFIDENCE...MEDIUM
BETTER MOISTURE ADVECTION THIS PERIOD THOUGH LLJ PROGGD BY BOTH
THE GFS AND ECMWF TO COLLAPSE TO OUR SOUTH. BUT THERE IS SOME
MOISTURE ADVECTION WITH THE INFLUENCE OF THE SHORTWAVE TROUGH. 00Z
ECMWF SHOWS THE LEAST QPF WITH THIS SYSTEM WHILE THE GFS AND GEM
SHOW A BIT MORE OF A NORTHERN MAX ACROSS OUR AREA, ALL MODELS
SUGGEST BEST CONVECTION WILL BE FURTHER SOUTH SHIFTING FROM THE
CENTRAL PLAINS INTO THE MID MISSISSIPPI VALLEY. OVERALL SURFACE
PATTERN WEAK THOUGH INCREASED FORCING VIA UPPER WAVE AND MORE
MOISTURE WILL LEAD TO MAINTAINING THE TRENDS OF THE ALLBLEND POPS.
WEDNESDAY AND THURSDAY - CONFIDENCE...LOW
WHILE DETAILS ARE YET TO GET WORKED OUT...THE GENERAL IDEA OF THE
GFS AND ECMWF IS TO TAKE AN ORGANIZING LOW PRESSURE SYSTEM FROM
VCNTY OF THE CNTRL PLAINS INTO THE EASTERN LAKES. THE TREND IS FOR
A SOUTHERN TRACK WHICH KEEPS US ON THE COOL SIDE WITH A GREATER
LIKELIHOOD FOR A FALL-LIKE STEADIER RAIN SETUP THOUGH
TIMING...TRACK AND STRENGTH OF LOW STILL VARIABLE AMONGST THE
MODELS.
AVIATION/12Z TAFS/...LOOK FOR VFR CONDITIONS THROUGH THE TAF PERIOD.
A COLD FRONT WILL SWEEP THROUGH MADISON AROUND 11-12Z THIS MORNING
AND REACH MILWAUKEE AROUND 14Z. WE COULD SEE SHOWERS AND THUNDERSTORMS
EXPAND ALONG THE FRONT THIS MORNING AS SOME WEAK CONVECTION MOVES
NORTHEAST OUT OF IOWA. CONDITIONS COULD BRIEFLY DROP TO MVFR LEVELS
IN ANY STRONGER STORMS. MORE POST FRONTAL SHOWERS AND STORMS ARE
POSSIBLE ACROSS THE SOUTHEAST WISCONSIN TAF SITES LATER THIS AFTERNOON
AND INTO THE EVENING AS A WEAK MID LEVEL WAVE MOVES BY. OTHERWISE...
LOOK FOR CLEARING SKIES FROM NORTHWEST TO SOUTHEAST OVERNIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...WOOD
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
SATURDAY THROUGH THURSDAY...COLLAR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
845 AM CDT FRI SEP 5 2014
.UPDATED...
845 AM CDT FRI SEP 5 2014
WEAK UPPER LEVEL SHORTWAVE TROUGH IS WORKING ON THE EDGE OF THE
ELEVATED INSTABILITY RIDGE AND SOME WEAK SLOPING FROTOGENETIC
FORCING TO FIRE AREAS OF SHOWERS - PERHAPS A FEW THUNDERSTORMS -
ACROSS NORTHEAST IA THIS MORNING. MESO MODELS IN FAIRLY GOOD
AGREEMENT IN TRACKING THIS NORTHEAST THROUGH THE MORNING
HOURS...WITH A DECREASING TREND BY 18Z. THE PCPN IS COMING OUT OF
MID CLOUDS...AND ACCUMULATIONS WILL BE MINIMAL.
MEANWHILE...ANOTHER SHORTWAVE LOOKS TO TAKE AIM ON THE FORECAST AREA
BY MID/LATE AFTERNOON...SPINNING OUT OF THE CENTRAL PLAINS. HERE
AGAIN...MESO MODELS IN DECENT AGREEMENT IN HAVING THIS FEATURE SPIT
OUT A FEW SHOWERS - PERHAPS SOME THUNDER.
SO...HAVE INCREASED THE RAIN CHANCES ACROSS THE SOUTH FOR THIS
MORNING...AND AGAIN FOR LATER THIS AFTERNOON. THESE LATE AFTERNOON
CHANCES MAY HAVE TO BE INCREASED EVEN MORE...AND CARRIED INTO THE
EARLY EVENING. EXPECT SOME BREAK FOR THE EARLY PART OF THE
AFTERNOON.
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT FRI SEP 5 2014
THE MAIN FOCUS IN THE SHORT TERM IS ON THE PRECIPITATION/TEMPERATURE/DEW
POINT TRENDS AS A COLD FRONT MOVES THROUGH THE REGION.
CURRENTLY...A SURFACE COLD FRONT EXTENDS FROM THE WESTERN UP OF
MICHIGAN DOWN THROUGH SOUTHWEST WISCONSIN AND SOUTH CENTRAL IOWA.
THE AIR MASS BEHIND THIS FRONT IS MUCH COOLER AND LESS HUMID WITH
TEMPERATURES DROPPING FROM THE UPPER 70S TO THE MID 50S AND DEW
POINTS GOING FROM THE MID 70S TO THE UPPER 40S. WHILE THE
ENVIRONMENT IN THE WARM SECTOR IS CAPPED OFF...SOME SLOPING LOW
LEVEL FRONTOGENESIS IS BEING AIDED BY A MID LEVEL TROUGH DIGGING
ACROSS NORTH DAKOTA/NORTHERN MINNESOTA AND HAS PRODUCED A BAND OF
CONVECTION ACROSS THE NORTHERN HALF OF IOWA. THIS RAIN WILL TRACK
TO THE NORTHEAST/EAST THIS MORNING BUT LIKELY WEAKEN AS IT LEAVES
THE DEEPER FORCING IN CENTRAL IOWA. THE 05.07Z RAP SHOWS THAT THE
0-3KM MUCAPE DROPS QUITE A BIT ONCE YOU REACH THIS
PRECIPITATION AND VERTICAL SHEAR PROFILES SHOW ONLY ABOUT 20-30KTS
OF 0-6KM SHEAR WITH MUCH OF IT AROUND 900-750MB. BASED ON
THIS...AM NOT EXPECTING MUCH IN THE WAY OF SEVERE WEATHER BUT
THAT THERE WILL BE A PERIOD OF LIGHT TO MODERATE
RAINFALL...PARTICULARLY ACROSS NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN.
CLOUD COVER WILL LIKELY LINGER THROUGH MUCH OF THE DAY AS ANOTHER
MID LEVEL SHORT WAVE TROUGH TRACKS TO THE EAST FROM EASTERN
COLORADO/WESTERN NEBRASKA ON THROUGH IOWA TODAY. 06.00Z NAM/GFS
FORECAST SOUNDINGS SHOW A SATURATING MID LEVEL LAYER WITH DRY AIR
STUCK UNDERNEATH IT. WHILE THE FOCUS APPEARS TO MAINLY BE ACROSS
THE SOUTHERN HALF OF IOWA INTO TONIGHT...THE 05.00Z NAM/GFS/ECMWF
DO HINT AT SOME LIGHT QPF MAKING IT INTO THE REGION. CONFIDENCE IS
NOT HIGH ENOUGH RIGHT NOW WITH WHAT WILL WIN OUT IN THIS BATTLE OF
DRY AIR...SO HAVE KEPT THE FORECAST DRY INTO TONIGHT FOR THE TIME
BEING.
OTHERWISE...HIGH TEMPERATURES HAVE ALREADY BEEN HIT FOR THE DAY AS
THEY WILL DROP INTO THIS MORNING AND THEN MAKE A SMALL DIURNAL
BUMP THIS AFTERNOON BEFORE DROPPING QUICKLY TONIGHT. LOW LEVEL
WINDS LOOK LIKE THEY SHOULD BE STRONG ENOUGH TO KEEP ANY VALLEY
FOG FROM FORMING...BUT WILL HAVE TO MONITOR THE CONDITIONS INTO
TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 AM CDT FRI SEP 5 2014
FAIRLY QUIET EXTENDED PERIOD WITH THE COOLER TEMPERATURES THE MAIN
STORY. THE COOLEST PERIOD APPEARS TO BE THIS WEEKEND AS +6C TO +8C
850MB AIR SITS OVER THE REGION BEFORE WARMER AIR GETS ADVECTED IN
ON THE BACK SIDE OF THE RIDGE EARLY NEXT WEEK. THE NEXT CHANCES
FOR PRECIPITATION ARE ON MONDAY INTO THURSDAY AS A MID LEVEL
SHORT WAVE TROUGH MOVES THROUGH THE REGION. NOT MUCH INSTABILITY
TO WORK WITH AS THE 05.00Z GFS/ECMWF SHOW LESS THAN 1000 J/KG OF
0-3KM MUCAPE AROUND THE REGION SO DO NOT EXPECT MUCH IN THE WAY
OF WIDESPREAD THUNDERSTORMS...PARTICULARLY ANYTHING CONSIDERED
SEVERE.
A MORE SIGNIFICANT COLD PUSH LOOKS LIKE IT WILL MOVE IN ON
THURSDAY WITH 850MB TEMPERATURES DROPPING BELOW 0C. THIS WILL
LIKELY LEAD TO SOME LOW TEMPERATURES DIPPING INTO THE 30S GOING
INTO FRIDAY MORNING AND THE POTENTIAL FOR SOME FROST IN THE
TYPICAL LOW/COLD BOG AREAS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 625 AM CDT FRI SEP 5 2014
A COOLER/DRIER AIRMASS WAS SPREADING ACROSS THE TAF SITES THIS
MORNING...IN THE WAKE OF THE COLD FRONT THAT WAS ALREADY INTO
SOUTHEAST WI/IA. GENERALLY GOOD VFR CONDITIONS EXPECTED AT THE TAF
SITES TODAY/TONIGHT AS CANADIAN HIGH PRESSURE BUILDS INTO THE UPPER
MIDWEST. SOME MOISTURE LIFTING NORTHWARD OVER THE FRONTAL BOUNDARY
MAY SPREAD SOME -SHRA INTO THE KLSE AREA THRU THE MORNING. THIS
FORCING EXPECTED TO SLOWLY SHIFT SOUTH THRU THE MORNING AND LEFT THE
VCSH/-SHRA MENTION OUT OF THE KLSE TAF AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATED......RIECK
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
625 AM CDT FRI SEP 5 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT FRI SEP 5 2014
THE MAIN FOCUS IN THE SHORT TERM IS ON THE PRECIPITATION/TEMPERATURE/DEW
POINT TRENDS AS A COLD FRONT MOVES THROUGH THE REGION.
CURRENTLY...A SURFACE COLD FRONT EXTENDS FROM THE WESTERN UP OF
MICHIGAN DOWN THROUGH SOUTHWEST WISCONSIN AND SOUTH CENTRAL IOWA.
THE AIR MASS BEHIND THIS FRONT IS MUCH COOLER AND LESS HUMID WITH
TEMPERATURES DROPPING FROM THE UPPER 70S TO THE MID 50S AND DEW
POINTS GOING FROM THE MID 70S TO THE UPPER 40S. WHILE THE
ENVIRONMENT IN THE WARM SECTOR IS CAPPED OFF...SOME SLOPING LOW
LEVEL FRONTOGENESIS IS BEING AIDED BY A MID LEVEL TROUGH DIGGING
ACROSS NORTH DAKOTA/NORTHERN MINNESOTA AND HAS PRODUCED A BAND OF
CONVECTION ACROSS THE NORTHERN HALF OF IOWA. THIS RAIN WILL TRACK
TO THE NORTHEAST/EAST THIS MORNING BUT LIKELY WEAKEN AS IT LEAVES
THE DEEPER FORCING IN CENTRAL IOWA. THE 05.07Z RAP SHOWS THAT THE
0-3KM MUCAPE DROPS QUITE A BIT ONCE YOU REACH THIS
PRECIPITATION AND VERTICAL SHEAR PROFILES SHOW ONLY ABOUT 20-30KTS
OF 0-6KM SHEAR WITH MUCH OF IT AROUND 900-750MB. BASED ON
THIS...AM NOT EXPECTING MUCH IN THE WAY OF SEVERE WEATHER BUT
THAT THERE WILL BE A PERIOD OF LIGHT TO MODERATE
RAINFALL...PARTICULARLY ACROSS NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN.
CLOUD COVER WILL LIKELY LINGER THROUGH MUCH OF THE DAY AS ANOTHER
MID LEVEL SHORT WAVE TROUGH TRACKS TO THE EAST FROM EASTERN
COLORADO/WESTERN NEBRASKA ON THROUGH IOWA TODAY. 06.00Z NAM/GFS
FORECAST SOUNDINGS SHOW A SATURATING MID LEVEL LAYER WITH DRY AIR
STUCK UNDERNEATH IT. WHILE THE FOCUS APPEARS TO MAINLY BE ACROSS
THE SOUTHERN HALF OF IOWA INTO TONIGHT...THE 05.00Z NAM/GFS/ECMWF
DO HINT AT SOME LIGHT QPF MAKING IT INTO THE REGION. CONFIDENCE IS
NOT HIGH ENOUGH RIGHT NOW WITH WHAT WILL WIN OUT IN THIS BATTLE OF
DRY AIR...SO HAVE KEPT THE FORECAST DRY INTO TONIGHT FOR THE TIME
BEING.
OTHERWISE...HIGH TEMPERATURES HAVE ALREADY BEEN HIT FOR THE DAY AS
THEY WILL DROP INTO THIS MORNING AND THEN MAKE A SMALL DIURNAL
BUMP THIS AFTERNOON BEFORE DROPPING QUICKLY TONIGHT. LOW LEVEL
WINDS LOOK LIKE THEY SHOULD BE STRONG ENOUGH TO KEEP ANY VALLEY
FOG FROM FORMING...BUT WILL HAVE TO MONITOR THE CONDITIONS INTO
TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 AM CDT FRI SEP 5 2014
FAIRLY QUIET EXTENDED PERIOD WITH THE COOLER TEMPERATURES THE MAIN
STORY. THE COOLEST PERIOD APPEARS TO BE THIS WEEKEND AS +6C TO +8C
850MB AIR SITS OVER THE REGION BEFORE WARMER AIR GETS ADVECTED IN
ON THE BACK SIDE OF THE RIDGE EARLY NEXT WEEK. THE NEXT CHANCES
FOR PRECIPITATION ARE ON MONDAY INTO THURSDAY AS A MID LEVEL
SHORT WAVE TROUGH MOVES THROUGH THE REGION. NOT MUCH INSTABILITY
TO WORK WITH AS THE 05.00Z GFS/ECMWF SHOW LESS THAN 1000 J/KG OF
0-3KM MUCAPE AROUND THE REGION SO DO NOT EXPECT MUCH IN THE WAY
OF WIDESPREAD THUNDERSTORMS...PARTICULARLY ANYTHING CONSIDERED
SEVERE.
A MORE SIGNIFICANT COLD PUSH LOOKS LIKE IT WILL MOVE IN ON
THURSDAY WITH 850MB TEMPERATURES DROPPING BELOW 0C. THIS WILL
LIKELY LEAD TO SOME LOW TEMPERATURES DIPPING INTO THE 30S GOING
INTO FRIDAY MORNING AND THE POTENTIAL FOR SOME FROST IN THE
TYPICAL LOW/COLD BOG AREAS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 625 AM CDT FRI SEP 5 2014
A COOLER/DRIER AIRMASS WAS SPREADING ACROSS THE TAF SITES THIS
MORNING...IN THE WAKE OF THE COLD FRONT THAT WAS ALREADY INTO
SOUTHEAST WI/IA. GENERALLY GOOD VFR CONDITIONS EXPECTED AT THE TAF
SITES TODAY/TONIGHT AS CANADIAN HIGH PRESSURE BUILDS INTO THE UPPER
MIDWEST. SOME MOISTURE LIFTING NORTHWARD OVER THE FRONTAL BOUNDARY
MAY SPREAD SOME -SHRA INTO THE KLSE AREA THRU THE MORNING. THIS
FORCING EXPECTED TO SLOWLY SHIFT SOUTH THRU THE MORNING AND LEFT THE
VCSH/-SHRA MENTION OUT OF THE KLSE TAF AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
320 AM CDT FRI SEP 5 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT FRI SEP 5 2014
THE MAIN FOCUS IN THE SHORT TERM IS ON THE PRECIPITATION/TEMPERATURE/DEW
POINT TRENDS AS A COLD FRONT MOVES THROUGH THE REGION.
CURRENTLY...A SURFACE COLD FRONT EXTENDS FROM THE WESTERN UP OF
MICHIGAN DOWN THROUGH SOUTHWEST WISCONSIN AND SOUTH CENTRAL IOWA.
THE AIR MASS BEHIND THIS FRONT IS MUCH COOLER AND LESS HUMID WITH
TEMPERATURES DROPPING FROM THE UPPER 70S TO THE MID 50S AND DEW
POINTS GOING FROM THE MID 70S TO THE UPPER 40S. WHILE THE
ENVIRONMENT IN THE WARM SECTOR IS CAPPED OFF...SOME SLOPING LOW
LEVEL FRONTOGENESIS IS BEING AIDED BY A MID LEVEL TROUGH DIGGING
ACROSS NORTH DAKOTA/NORTHERN MINNESOTA AND HAS PRODUCED A BAND OF
CONVECTION ACROSS THE NORTHERN HALF OF IOWA. THIS RAIN WILL TRACK
TO THE NORTHEAST/EAST THIS MORNING BUT LIKELY WEAKEN AS IT LEAVES
THE DEEPER FORCING IN CENTRAL IOWA. THE 05.07Z RAP SHOWS THAT THE
0-3KM MUCAPE DROPS QUITE A BIT ONCE YOU REACH THIS
PRECIPITATION AND VERTICAL SHEAR PROFILES SHOW ONLY ABOUT 20-30KTS
OF 0-6KM SHEAR WITH MUCH OF IT AROUND 900-750MB. BASED ON
THIS...AM NOT EXPECTING MUCH IN THE WAY OF SEVERE WEATHER BUT
THAT THERE WILL BE A PERIOD OF LIGHT TO MODERATE
RAINFALL...PARTICULARLY ACROSS NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN.
CLOUD COVER WILL LIKELY LINGER THROUGH MUCH OF THE DAY AS ANOTHER
MID LEVEL SHORT WAVE TROUGH TRACKS TO THE EAST FROM EASTERN
COLORADO/WESTERN NEBRASKA ON THROUGH IOWA TODAY. 06.00Z NAM/GFS
FORECAST SOUNDINGS SHOW A SATURATING MID LEVEL LAYER WITH DRY AIR
STUCK UNDERNEATH IT. WHILE THE FOCUS APPEARS TO MAINLY BE ACROSS
THE SOUTHERN HALF OF IOWA INTO TONIGHT...THE 05.00Z NAM/GFS/ECMWF
DO HINT AT SOME LIGHT QPF MAKING IT INTO THE REGION. CONFIDENCE IS
NOT HIGH ENOUGH RIGHT NOW WITH WHAT WILL WIN OUT IN THIS BATTLE OF
DRY AIR...SO HAVE KEPT THE FORECAST DRY INTO TONIGHT FOR THE TIME
BEING.
OTHERWISE...HIGH TEMPERATURES HAVE ALREADY BEEN HIT FOR THE DAY AS
THEY WILL DROP INTO THIS MORNING AND THEN MAKE A SMALL DIURNAL
BUMP THIS AFTERNOON BEFORE DROPPING QUICKLY TONIGHT. LOW LEVEL
WINDS LOOK LIKE THEY SHOULD BE STRONG ENOUGH TO KEEP ANY VALLEY
FOG FROM FORMING...BUT WILL HAVE TO MONITOR THE CONDITIONS INTO
TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 AM CDT FRI SEP 5 2014
FAIRLY QUIET EXTENDED PERIOD WITH THE COOLER TEMPERATURES THE MAIN
STORY. THE COOLEST PERIOD APPEARS TO BE THIS WEEKEND AS +6C TO +8C
850MB AIR SITS OVER THE REGION BEFORE WARMER AIR GETS ADVECTED IN
ON THE BACK SIDE OF THE RIDGE EARLY NEXT WEEK. THE NEXT CHANCES
FOR PRECIPITATION ARE ON MONDAY INTO THURSDAY AS A MID LEVEL
SHORT WAVE TROUGH MOVES THROUGH THE REGION. NOT MUCH INSTABILITY
TO WORK WITH AS THE 05.00Z GFS/ECMWF SHOW LESS THAN 1000 J/KG OF
0-3KM MUCAPE AROUND THE REGION SO DO NOT EXPECT MUCH IN THE WAY
OF WIDESPREAD THUNDERSTORMS...PARTICULARLY ANYTHING CONSIDERED
SEVERE.
A MORE SIGNIFICANT COLD PUSH LOOKS LIKE IT WILL MOVE IN ON
THURSDAY WITH 850MB TEMPERATURES DROPPING BELOW 0C. THIS WILL
LIKELY LEAD TO SOME LOW TEMPERATURES DIPPING INTO THE 30S GOING
INTO FRIDAY MORNING AND THE POTENTIAL FOR SOME FROST IN THE
TYPICAL LOW/COLD BOG AREAS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1126 PM CDT THU SEP 4 2014
COLD FRONT IS MAKING ITS WAY THROUGH THE TAF SITES EARLY THIS
MORNING. THERE HAS BEEN A BRIEF BATCH OF MVFR STRATUS DEVELOPING
IN THE WAKE OF THE FRONT...LIKELY A RESULT OF THE COOLER AIR
COMING IN QUICKER THAN THE HUMID AIR EXITING. THIS STRATUS SHOULD
BE OUT OF RST BY 07Z...WITH A POSSIBLE IMPACT TIME OF 07-09Z AT
LSE. THERE HAVE ALSO BEEN SHOWERS AND THUNDERSTORMS DEVELOPING
BEHIND THE FRONT...ESPECIALLY ACROSS IOWA. THESE ARE SPREADING
NORTHEAST AND COULD BE SOUTH OF OR NEAR LSE FOR THE 06-10Z PERIOD.
THEREFORE...HAVE A VCSH COVERING THIS.
AFTER 10Z...DRIER AIR OVER WESTERN MN WILL COME INTO THE TAF
SITES ON A 10 KT NORTHWEST WIND...RESULTING IN VFR CONDITIONS FOR
THE REST OF THE TAF PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
305 AM CDT FRI SEP 5 2014
.TODAY...FORECAST CONFIDENCE IS MEDIUM.
THE MAIN ISSUE FOR TODAY IS THE ARRIVAL OF A STRONG COLD FRONT EARLY
THIS MORNING...EXITING EAST OF MILWAUKEE BY LATE MORNING. AN AREA
OF WEAKENING CONVECTION OVER IOWA EARLY THIS MORNING IS BEING PICKED
UP BY THE HRRR AND TRACKED ACROSS THE FORECAST AREA THIS
MORNING...MOSTLY BEFORE 8 AM. THE HRRR ALSO SUGGESTS INTENSIFICATION
AND EXPANSION. THIS ACTIVITY IS FOCUSED ALONG THE H8 COLD
FRONT...WHICH IS POST FRONTAL OF THE SFC FRONT. THE CONCERN IS IT
MAY CATCH UP WITH THE SFC FRONT OVER OUR WRN CWA THIS MORNING AND
BECOME MORE SFC BASED. INSTABILITY IS PRETTY HIGH ACROSS THE AREA
RIGHT NOW...SO WILL HAVE TO WATCH TRENDS VERY CLOSELY. THERE IS A
DISTINCT LACK OF MID AND UPPER LEVEL SUPPORT AND DEEP LAYER SHEAR IS
RATHER WEAK. WILL HANG ONTO A CHANCE FOR STORMS UNTIL THE FRONT
EXITS.
THEN SOME MID LEVEL FORCING FROM AN APPROACHING SHORT WAVE COULD
RESULT IN SOME INCREASING SHOWERS SHOWERS AND ISOLATED THUNDERSTORMS
ACROSS THE SOUTHEAST THIS AFTERNOON AND INTO THE EVENING HOURS. THIS
WILL ALL BE POST FRONTAL WITH A DECENT RIGHT REAR UPPER JET QUADRANT
HELPING TO SUPPORT DECENT 700-600MB FRONTOGENESIS. THE MAIN
QUESTION IS WHETHER THERE/LL BE ENOUGH DEEP MOISTURE LEFT TO SUPPORT
SHOWERS. SOME OF THE MODELS SCOUR OUT THE RAIN ONCE THE FRONT
EXITS...OTHERS DO THE POST FRONTAL GIG...SO WILL HANG ONTO POPS SE.
COOLER AND DRIER AIR WILL CONTINUE TO OVERSPREAD THE AREA AS THE DAY
PROGRESSES.
.TONIGHT...FORECAST CONFIDENCE IS HIGH.
OTHER THAN SOME LINGERING EVENING SHOWERS POSSIBLE IN THE
SOUTHEAST...THE COOLER...DRIER TREND WILL CONTINUE. SKIES WILL
GRADUALLY CLEAR WITH LOWS DIPPING INTO THE LOWER 50S OVER ALL BUT
THE SOUTHEAST. THE CLOUDS CLEARING LATER ACROSS THE SOUTHEAST WILL
KEEP TEMPS UP A BIT HIGHER.
.SATURDAY AND SUNDAY - CONFIDENCE...MEDIUM
HIGH PRESSURE IN THE CENTRAL PLAINS SATURDAY WILL EXPAND ACROSS THE
GREAT LAKES SUNDAY. NORTHWEST WINDS AND THERMAL TROUGH LINGERS THROUGH
SATURDAY EVENING. SUBTLE MODIFICATION FOR SUNDAY AS 850 TEMPS MODIFY
ONLY SLIGHTLY. LIGHT WIND REGIME WITH SURFACE HIGH WELL IN PLACE AND
GRADIENT WEAK.
.MONDAY - CONFIDENCE...MEDIUM
MODELS SHOW 500 MILLIBAR TROUGH APPROACHING INTO IA/MN BY END OF THE
DAY. 850 JET AXIS REMAINS WEST AND LIKE THE DRY LOOK FOR SRN WI.
WITH HIGH TO THE EAST THE FLOW WILL BECOME DECIDEDLY FROM THE
SOUTH...SO GRADUAL MOISTURE ADVECTION THOUGH BEST PUSH OF THIS HOLDS
OFF TO OUR WEST DURING THE DAY.
.MONDAY NIGHT AND TUESDAY - CONFIDENCE...MEDIUM
BETTER MOISTURE ADVECTION THIS PERIOD THOUGH LLJ PROGGD BY BOTH
THE GFS AND ECMWF TO COLLAPSE TO OUR SOUTH. BUT THERE IS SOME
MOISTURE ADVECTION WITH THE INFLUENCE OF THE SHORTWAVE TROUGH. 00Z
ECMWF SHOWS THE LEAST QPF WITH THIS SYSTEM WHILE THE GFS AND GEM
SHOW A BIT MORE OF A NORTHERN MAX ACROSS OUR AREA, ALL MODELS
SUGGEST BEST CONVECTION WILL BE FURTHER SOUTH SHIFTING FROM THE
CENTRAL PLAINS INTO THE MID MISSISSIPPI VALLEY. OVERALL SURFACE
PATTERN WEAK THOUGH INCREASED FORCING VIA UPPER WAVE AND MORE
MOISTURE WILL LEAD TO MAINTAINING THE TRENDS OF THE ALLBLEND POPS.
.WEDNESDAY AND THURSDAY - CONFIDENCE...LOW
WHILE DETAILS ARE YET TO GET WORKED OUT...THE GENERAL IDEA OF THE
GFS AND ECMWF IS TO TAKE AN ORGANIZING LOW PRESSURE SYSTEM FROM
VCNTY OF THE CNTRL PLAINS INTO THE EASTERN LAKES. THE TREND IS FOR
A SOUTHERN TRACK WHICH KEEPS US ON THE COOL SIDE WITH A GREATER
LIKELIHOOD FOR A FALL-LIKE STEADIER RAIN SETUP THOUGH
TIMING...TRACK AND STRENGTH OF LOW STILL VARIABLE AMONGST THE
MODELS.
&&
.AVIATION/12Z TAFS/...LOOK FOR VFR CONDITIONS THROUGH THE TAF PERIOD.
A COLD FRONT WILL SWEEP THROUGH MADISON AROUND 11-12Z THIS MORNING
AND REACH MILWAUKEE AROUND 14Z. WE COULD SEE SHOWERS AND THUNDERSTORMS
EXPAND ALONG THE FRONT THIS MORNING AS SOME WEAK CONVECTION MOVES
NORTHEAST OUT OF IOWA. CONDITIONS COULD BRIEFLY DROP TO MVFR LEVELS
IN ANY STRONGER STORMS. MORE POST FRONTAL SHOWERS AND STORMS ARE
POSSIBLE ACROSS THE SOUTHEAST WISCONSIN TAF SITES LATER THIS AFTERNOON
AND INTO THE EVENING AS A WEAK MID LEVEL WAVE MOVES BY. OTHERWISE...
LOOK FOR CLEARING SKIES FROM NORTHWEST TO SOUTHEAST OVERNIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
SATURDAY THROUGH THURSDAY...COLLAR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1126 PM CDT THU SEP 4 2014
.UPDATE...
ISSUED AT 855 PM CDT THU SEP 4 2014
CONFIDENCE IS LOWERING ON POTENTIAL FOR SHOWERS AND THUNDERSTORMS
TONIGHT. LATEST SURFACE ANALYSIS SHOWS A COLD FRONT FROM NEAR
MENOMONIE WI TO WABASHA MN AND CHARLES CITY IA. RAP SHOWS LESS
THAN 25 J/KG CIN ACROSS MUCH OF THE FORECAST
AREA...HOWEVER...SURFACE BASED CIN IS MORE ON THE ORDER OF 50-75
J/KG. THIS CIN REFLECTS CAPPING IN PLACE SEEN ON THE 00Z MPX
SOUNDING. STILL WAITING TO SEE IF FRONTOGENESIS ON AND BEHIND THE
COLD FRONT CAN INITIATE CONVECTION. CERTAINLY PLENTY OF
INSTABILITY SHOULD THE CAP WEAKEN AS ALSO SEEN ON THE 00Z MPX
SOUNDING...THUS CANNOT REMOVE CHANCES COMPLETELY FOR THE REST OF
TONIGHT. SHOULD CONVECTION DEVELOP...AN ISOLATED SEVERE STORM IS
POSSIBLE...PARTICULARLY HERE DURING THE EVENING HOURS. AFTER
MIDNIGHT...CAPE DIMINISHES WHICH WILL LIMIT SEVERE POTENTIAL.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 327 PM CDT THU SEP 4 2014
MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE THUNDERSTORMS.
LATEST SURFACE ANALYSIS PLACED LOW PRESSURE OVER CENTRAL
MINNESOTA...EDGING EAST. A COLD FRONT EXTENDED SOUTHWARD INTO WESTERN
IOWA WHILE A WARM FRONT WAS POSITIONED NEAR THE INTERSTATE 94
CORRIDOR IN EAST CENTRAL MINNESOTA THROUGH WESTERN WISCONSIN.
EXTENSIVE CLOUD COVER OVER MUCH OF THE FORECAST AREA WAS HELPING TO
HOLD TEMPERATURES DOWN A BIT. SHOWERS AND STORMS ARE DEVELOPING
ACROSS AREAS NORTH OF INTERSTATE 90 DESPITE A FAIRLY STOUT CAP IN
PLACE. FORECAST SOUNDINGS ARE INDICATING 750 MB TEMPERATURES
HOVERING RIGHT AROUND 15 C. SOUNDINGS SUGGEST THIS CAP WILL WEAKEN
AS A SHORTWAVE APPROACHES FROM NEBRASKA/SOUTH DAKOTA THIS AFTERNOON
INTO THIS EVENING JUST AS THE COLD FRONT IS MAKING ITS WAY INTO
NORTHWESTERN SECTIONS OF THE FORECAST AREA. MESOSCALE MODELS ARE
FIRING SHOWERS AND STORMS ALONG AND BEHIND THE FRONT THIS EVENING.
IF THIS SCENARIO PLAYS OUT...THE MAIN THREATS FROM THE STORMS WOULD
BE LARGE HAIL AND HEAVY RAINFALL. WE SHOULD SEE A BAND OF SHOWERS
AND STORMS DEVELOP RIGHT OVER THE FORECAST AREA THIS EVENING THEN
THIS BAND WILL GRADUALLY PUSH SOUTHEAST DURING THE OVERNIGHT HOURS
AS THE FRONT SAGS SOUTHWARD. MUCH COOLER AIR PUSHES INTO THE
FORECAST AREA IN THE WAKE OF THE FRONT TONIGHT INTO FRIDAY WITH 850
MB TEMPS GOING FROM 25 C THIS AFTERNOON TO AROUND 10 C BY FRIDAY
AFTERNOON. A VERY COMFORTABLE DAY IS IN STORE FOR THE REGION ON
FRIDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. PLAN PARTLY SUNNY
SKIES ACROSS THE REGION WITH HIGHS RANGING FROM THE MID 60 TO LOWER
70S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 327 PM CDT THU SEP 4 2014
HIGH PRESSURE REMAINS IN CONTROL FRIDAY NIGHT INTO SUNDAY AS THE
REGION REMAINS IN A COOL NORTHWEST FLOW REGIME. WITH THE RIDGE AXIS
NEARBY PROVIDING LIGHT AND VARIABLE WINDS FROM THE SURFACE THROUGH 2
KFT MAY SET THE STAGE FOR AREAS OF FOG LATE SATURDAY NIGHT INTO
SUNDAY MORNING. HAVE INCLUDED PATCHY FOG ALONG RIVER VALLEY
LOCATIONS AND OVER CENTRAL WISCONSIN DURING THIS TIMEFRAME. THE NEXT
CHANCE FOR SHOWERS AND STORMS ACROSS THE REGION ARRIVES ON MONDAY AS
FLOW ALOFT TURNS MORE ZONAL AND A SHORTWAVE TROUGH MOVES IN FROM THE
PLAINS. TEMPERATURES WILL REMAIN SEASONABLY COOL THROUGH THE PERIOD
WITH HIGHS MAINLY IN THE 70S. A MORE UNSETTLED PATTERN IS EXPECTED
TO DEVELOP NEXT WEEK AND WILL REMAIN OVER THE REGION THROUGH
THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1126 PM CDT THU SEP 4 2014
COLD FRONT IS MAKING ITS WAY THROUGH THE TAF SITES EARLY THIS
MORNING. THERE HAS BEEN A BRIEF BATCH OF MVFR STRATUS DEVELOPING
IN THE WAKE OF THE FRONT...LIKELY A RESULT OF THE COOLER AIR
COMING IN QUICKER THAN THE HUMID AIR EXITING. THIS STRATUS SHOULD
BE OUT OF RST BY 07Z...WITH A POSSIBLE IMPACT TIME OF 07-09Z AT
LSE. THERE HAVE ALSO BEEN SHOWERS AND THUNDERSTORMS DEVELOPING
BEHIND THE FRONT...ESPECIALLY ACROSS IOWA. THESE ARE SPREADING
NORTHEAST AND COULD BE SOUTH OF OR NEAR LSE FOR THE 06-10Z PERIOD.
THEREFORE...HAVE A VCSH COVERING THIS.
AFTER 10Z...DRIER AIR OVER WESTERN MN WILL COME INTO THE TAF
SITES ON A 10 KT NORTHWEST WIND...RESULTING IN VFR CONDITIONS FOR
THE REST OF THE TAF PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...AJ
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1035 AM MDT FRI SEP 5 2014
.UPDATE...
ISSUED AT 1022 AM MDT FRI SEP 5 2014
FOG AND LOW CLOUDS ARE NOT IN A HURRY TO DISSIPATE NEAR THE
SOUTHERN LARAMIE RANGE. SOUTH TO SOUTHEAST WINDS WILL REMAIN IN
PLACE THROUGH TODAY AND TONIGHT...KEEPING THE LOW LEVEL INVERSION
IN PLACE ALONG WITH THE THREAT FOR FOG...ESPECIALLY NEAR THE
SUMMIT BETWEEN LARAMIE AND CHEYENNE. MAY NEED A DENSE FOG ADVISORY
FOR THE SOUTHERN LARAMIE RANGE ZONES TONIGHT AND POSSIBLY
CHEYENNE.
LOTS OF SUNSHINE WEST OF THE LARAMIE RANGE THIS MORNING. THE
SUNSHINE WILL LEAD TO ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS THIS AFTERNOON. THUNDERSTORMS WILL HAVE A VERY
DIFFICULT TIME MAKING THEIR WAY EAST OF THE LARAMIE RANGE AS THEY
WILL ENCOUNTER STABLE LOW LEVEL AIR.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 231 AM MDT FRI SEP 5 2014
A COUPLE BANDS OF SHOWERS MOVING ACROSS PARTS OF THE CWA EARLY
THIS MORNING LIKELY AIDED BY AN UPPER JET MOVING NORTHEAST ACROSS
THE REGION. EXPECT THIS ACTIVITY TO MOVE OUT OVER THE NEXT SEVERAL
HOURS BEFORE REGENERATING OVER THE MTNS THIS AFTERNOON AS A WEAK
IMPULSE IN WESTERLY UPPER FLOW INTERACTS WITH SOME WEAK
INSTABILITY AND SOME UPSLOPE COMPONENT IN THE SFC WIND FLOW.
ACTIVITY WILL HAVE DIFFICULTY MAKING MUCH PROGRESS EASTWARD WITH
CAPPING OVER THE PLAINS. RATHER COOL OVER THE EASTERN PLAINS OF
THE CWA TODAY WITH MOST AREAS LIKELY STAYING IN THE 60S AS A SFC
HIGH SETTLES ACROSS THE CENTRAL PLAINS. COOL TONIGHT WITH SHOWERS
ENDING IN THE EVENING THEN BASICALLY A REPEAT PERFORMANCE SATURDAY
WITH SHOWERS AND A FEW STORMS DEVELOPING OVER THE MTNS IN THE
AFTERNOON BUT AGAIN NOT MAKING A LOT OF PROGRESS EASTWARD. ABOUT 5
TO 10 DEGREES WARMER SATURDAY WITH RETURN FLOW ON BACK SIDE OF
DEPARTING SFC HIGH. ADD ABOUT ANOTHER 5 TO 10 DEGREES FOR MAXS
SUNDAY WITH MORE OF A DOWNSLOPE FLOW AND SOME SUNSHINE. WIDELY
SCTD SHOWERS AND A FEW STORMS ONCE AGAIN INITIATING OVER THE MTNS
BUT MAKING A BIT BETTER PROGRESS OVER THE PLAINS.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 231 AM MDT FRI SEP 5 2014
MODEL CONSENSUS STILL POOR ON THE SYSTEM MIDWEEK. HUGE TEMPERATURE
BUST POTENTIAL WEDNESDAY AND THURSDAY DEPENDING ON WHICH MEDIUM
RANGE MODEL WINS OUT. FORECAST CHALLENGES IN THE EXTENDED DEAL
WITH MAINLY TEMPERATURES.
NORTHWEST FLOW FOR SUNDAY NIGHT WITH A WEAK SHORTWAVE MOVING
THROUGH NORTHERN WYOMING. HAVE SOME SLIGHT CHANCE POPS FOR THE
AREA SUNDAY NIGHT...MORE BASED ON WHAT THE GFS IS SHOWING. BUT
THEY SHOULD END FAIRLY QUICKLY AFTER MIDNIGHT. MONDAY LOOKS DRY
WITH GUIDANCE SHOWING MOST ALL OF THE QPF OVER COLORADO. DID KEEP
SOME LOW END CHANCE POPS FOR THE SNOWY AND SIERRA MADRE RANGES.
PRECIP REALLY DOES NOT GET INTO THE CHEYENNE CWFA UNTIL TUESDAY
AFTERNOON. BOTH THE GFS AND ECMWF HAVE POPS OUT IN CARBON COUNTY.
THIS IS WHERE MODEL GUIDANCE BEGINS TO DIVERGE.
GFS KEEPS 7000MB TEMPERATURES FAIRLY WARM TUESDAY NIGHT INTO
WEDNESDAY. TEMPERATURES STAY ABOVE FREEZING THROUGH WEDNESDAY
AFTERNOON. THE GFS DOES BRING A FRONT INTO THE AREA FROM THE
NORTH. 700MB TEMPERATURES FROM THE GFS RANGE FROM +6C TO +2C OVER
THE CWFA WEDNESDAY AFTERNOON. ECMWF ON THE OTHER HAND...HAS 700MB
TEMPERATURES OF +2C TO -2C OVER THE CWFA WEDNESDAY AFTERNOON.
WHILE THE ECMWF FORECASTS 700MB TEMPERATURES FALLING TO -6 TO -8C
THURSDAY NIGHT INTO FRIDAY...THE GFS KEEPS THE COLDER AIR NORTH
AND IS FORECASTING +10 TO +4C GRADIENT OVER WYOMING THROUGH FRIDAY
MORNING. DECIDED TO BEGIN GOING WITH THE MORE CONSISTENT
ECMWF...WHICH HAS BEEN SHOWING THIS COOL DOWN FOR THE PAST THREE
DAYS. USED HPC AND ECMWF GUIDANCE ON TEMPERATURES FOR THURSDAY AND
FRIDAY. WITH THIS FORECAST...THERE ARE GOING TO BE AREAS THAT WILL
MOST LIKELY SEE SNOW...ESPECIALLY CONVERSE/NIOBRARA COUNTIES IN
CENTRAL WYOMING. MAY STILL BE TOO WARM FOR SNOW IN THE NORTHERN
PANHANDLE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 453 AM MDT FRI SEP 5 2014
CEILINGS ARE STARTING TO COME DOWN NOW AS OF 11Z. HRRR SHOWING THE
SOUTHERN PANHANDLE...KCYS AND POSSIBLY KLAR COMING DOWN TO IFR
SHORTLY AFTER 12Z AND STAYING DOWN THROUGH AT LEAST 18Z. GENERALLY
FOLLOWED THE HRRR GUIDANCE ON FORECAST CONDITIONS THIS MORNING.
LOOKS LIKE A RETURN TO IFR THIS EVENING WITH UPSLOPING SOUTHEAST
WINDS.
&&
.FIRE WEATHER...
ISSUED AT 231 AM MDT FRI SEP 5 2014
FIRE WEATHER CONCERNS TO REMAIN LOW THROUGH THE WEEKEND WITH NON-
CRITICAL CONDITIONS EXPECTED WEATHER-WISE. SOMEWHAT COOL
CONDITIONS TODAY THEN A WARM UP OVER THE WEEKEND WITH DECREASING
CHANCES FOR RAIN.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...RE
LONG TERM...CLAYCOMB
AVIATION...CLAYCOMB
FIRE WEATHER...RE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
455 AM MDT FRI SEP 5 2014
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 231 AM MDT FRI SEP 5 2014
A COUPLE BANDS OF SHOWERS MOVING ACROSS PARTS OF THE CWA EARLY
THIS MORNING LIKELY AIDED BY AN UPPER JET MOVING NORTHEAST ACROSS
THE REGION. EXPECT THIS ACTIVITY TO MOVE OUT OVER THE NEXT SEVERAL
HOURS BEFORE REGENERATING OVER THE MTNS THIS AFTERNOON AS A WEAK
IMPULSE IN WESTERLY UPPER FLOW INTERACTS WITH SOME WEAK
INSTABILITY AND SOME UPSLOPE COMPONENT IN THE SFC WIND FLOW.
ACTIVITY WILL HAVE DIFFICULTY MAKING MUCH PROGRESS EASTWARD WITH
CAPPING OVER THE PLAINS. RATHER COOL OVER THE EASTERN PLAINS OF
THE CWA TODAY WITH MOST AREAS LIKELY STAYING IN THE 60S AS A SFC
HIGH SETTLES ACROSS THE CENTRAL PLAINS. COOL TONIGHT WITH SHOWERS
ENDING IN THE EVENING THEN BASICALLY A REPEAT PERFORMANCE SATURDAY
WITH SHOWERS AND A FEW STORMS DEVELOPING OVER THE MTNS IN THE
AFTERNOON BUT AGAIN NOT MAKING A LOT OF PROGRESS EASTWARD. ABOUT 5
TO 10 DEGREES WARMER SATURDAY WITH RETURN FLOW ON BACK SIDE OF
DEPARTING SFC HIGH. ADD ABOUT ANOTHER 5 TO 10 DEGREES FOR MAXS
SUNDAY WITH MORE OF A DOWNSLOPE FLOW AND SOME SUNSHINE. WIDELY
SCTD SHOWERS AND A FEW STORMS ONCE AGAIN INITIATING OVER THE MTNS
BUT MAKING A BIT BETTER PROGRESS OVER THE PLAINS.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 231 AM MDT FRI SEP 5 2014
MODEL CONSENSUS STILL POOR ON THE SYSTEM MIDWEEK. HUGE TEMPERATURE
BUST POTENTIAL WEDNESDAY AND THURSDAY DEPENDING ON WHICH MEDIUM
RANGE MODEL WINS OUT. FORECAST CHALLENGES IN THE EXTENDED DEAL
WITH MAINLY TEMPERATURES.
NORTHWEST FLOW FOR SUNDAY NIGHT WITH A WEAK SHORTWAVE MOVING
THROUGH NORTHERN WYOMING. HAVE SOME SLIGHT CHANCE POPS FOR THE
AREA SUNDAY NIGHT...MORE BASED ON WHAT THE GFS IS SHOWING. BUT
THEY SHOULD END FAIRLY QUICKLY AFTER MIDNIGHT. MONDAY LOOKS DRY
WITH GUIDANCE SHOWING MOST ALL OF THE QPF OVER COLORADO. DID KEEP
SOME LOW END CHANCE POPS FOR THE SNOWY AND SIERRA MADRE RANGES.
PRECIP REALLY DOES NOT GET INTO THE CHEYENNE CWFA UNTIL TUESDAY
AFTERNOON. BOTH THE GFS AND ECMWF HAVE POPS OUT IN CARBON COUNTY.
THIS IS WHERE MODEL GUIDANCE BEGINS TO DIVERGE.
GFS KEEPS 7000MB TEMPERATURES FAIRLY WARM TUESDAY NIGHT INTO
WEDNESDAY. TEMPERATURES STAY ABOVE FREEZING THROUGH WEDNESDAY
AFTERNOON. THE GFS DOES BRING A FRONT INTO THE AREA FROM THE
NORTH. 700MB TEMPERATURES FROM THE GFS RANGE FROM +6C TO +2C OVER
THE CWFA WEDNESDAY AFTERNOON. ECMWF ON THE OTHER HAND...HAS 700MB
TEMPERATURES OF +2C TO -2C OVER THE CWFA WEDNESDAY AFTERNOON.
WHILE THE ECMWF FORECASTS 700MB TEMPERATURES FALLING TO -6 TO -8C
THURSDAY NIGHT INTO FRIDAY...THE GFS KEEPS THE COLDER AIR NORTH
AND IS FORECASTING +10 TO +4C GRADIENT OVER WYOMING THROUGH FRIDAY
MORNING. DECIDED TO BEGIN GOING WITH THE MORE CONSISTENT
ECMWF...WHICH HAS BEEN SHOWING THIS COOL DOWN FOR THE PAST THREE
DAYS. USED HPC AND ECMWF GUIDANCE ON TEMPERATURES FOR THURSDAY AND
FRIDAY. WITH THIS FORECAST...THERE ARE GOING TO BE AREAS THAT WILL
MOST LIKELY SEE SNOW...ESPECIALLY CONVERSE/NIOBRARA COUNTIES IN
CENTRAL WYOMING. MAY STILL BE TOO WARM FOR SNOW IN THE NORTHERN
PANHANDLE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 453 AM MDT FRI SEP 5 2014
CEILINGS ARE STARTING TO COME DOWN NOW AS OF 11Z. HRRR SHOWING THE
SOUTHERN PANHANDLE...KCYS AND POSSIBLY KLAR COMING DOWN TO IFR
SHORTLY AFTER 12Z AND STAYING DOWN THROUGH AT LEAST 18Z. GENERALLY
FOLLOWED THE HRRR GUIDANCE ON FORECAST CONDITIONS THIS MORNING.
LOOKS LIKE A RETURN TO IFR THIS EVENING WITH UPSLOPING SOUTHEAST
WINDS.
&&
.FIRE WEATHER...
ISSUED AT 231 AM MDT FRI SEP 5 2014
FIRE WEATHER CONCERNS TO REMAIN LOW THROUGH THE WEEKEND WITH NON-
CRITICAL CONDITIONS EXPECTED WEATHER-WISE. SOMEWHAT COOL
CONDITIONS TODAY THEN A WARM UP OVER THE WEEKEND WITH DECREASING
CHANCES FOR RAIN.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RE
LONG TERM...CLAYCOMB
AVIATION...CLAYCOMB
FIRE WEATHER...RE
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
1040 PM MST SAT SEP 6 2014
.UPDATE...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
MOISTURE WILL CONTINUE TO INCREASE ACROSS THE AREA THIS WEEKEND.
SHOWERS AND THUNDERSTORMS ARE EXPECTED AT TIMES EACH DAY THROUGH
EARLY NEXT WEEK...WITH SOME LOCATIONS POSSIBLY SEEING BRIEF PERIODS
OF HEAVY RAIN. A GRADUAL DRYING TREND IS EXPECTED TO BEGIN NEXT WEEK
AS HIGH PRESSURE SLOWLY REBUILDS OVER THE REGION.
&&
.DISCUSSION...
A RATHER ACTIVE DAY THIS AFTERNOON AND EVENING ACROSS OUR
CWA...ESPECIALLY ACROSS SOUTH-CENTRAL ARIZONA...AS MOISTURE FROM
WEAKENING HURRICANE NORBERT BEGINS TO MOVE NORTHWARD INTO OUR
REGION. AS EXPECTED...WITH PWAT VALUES STILL AOB 1.50 INCH...THE
MAIN ISSUES THIS AFTERNOON AND EVENING WERE STRONG WINDS AND
WIDESPREAD DENSE BLOWING ACROSS THE GREATER PHOENIX AREA AS OUTFLOWS
FROM THUNDERSTORMS OVER PIMA AND PINAL COUNTIES MOVED NORTHWESTWARD
OVER THE REGION. LOCALLY HEAVY RAIN DID FALL IN SOME SPOTS...BUT
THEY HAVE BEEN MAINLY CONFINED SO FAR TO THE SAN TAN VALLEY AREA AND
OVER PORTIONS OF THE NORTH-CENTRAL AND SOUTH-CENTRAL PARTS OF THE
GREATER PHOENIX AREA...WITH MOST LOCATIONS STAYING DRY. ALONG WITH
THE HEAVY RAIN...PARTS OF THE SAN TAN VALLEY AREA ALSO SAW DAMAGING
WINDS...WITH GUSTS AS HIGH AS 60 MPH. ISOLATED THUNDERSTORMS ALSO
BROUGHT STRONG WINDS AND HEAVY DOWNPOURS TO A FEW LOCATIONS ACROSS
LA PAZ COUNTY IN AZ AND IMPERIAL COUNTY IN SE CA.
AS FAR AS THE FORECAST FOR THE REST OF TONIGHT AND INTO EARLY SUNDAY
IS CONCERNED...THE HRRR CONTINUES TO SHOW THE DEVELOPMENT OF SPOTTY
SHOWERS AND THUNDERSTORMS THROUGH THIS PERIOD...WITH ACTIVITY
GRADUALLY WORKING ITS WAY BACK WESTWARD INTO SW AZ AND SE CA...WHICH
IS CONSISTENT WITH CURRENT FORECASTS. ALTHOUGH THE LATEST NAM AND
GFS MODEL SUITES CONTINUE TO PUSH PWATS AOA 2.00 INCHES ON
SUNDAY...THERE IS STILL A FAIR BIT OF UNCERTAINTY ON HOW MUCH/HOW
WIDESPREAD RAINFALL WILL FALL ON SUNDAY...DUE TO THE FACT THAT
LEFTOVER DEBRIS CLOUDS AND A RATHER WORKED-OVER ATMOSPHERE MAY
INHIBIT CONVECTIVE DEVELOPMENT DURING THIS PERIOD. GIVEN THE AMPLE
MOISTURE THAT IS EXPECTED TO BE AVAILABLE...ANY STORMS SHOULD BE
EFFICIENT RAIN PRODUCERS...MAKING THE GREATEST THREAT FROM THESE
STORMS BEING HEAVY RAIN/FLOODING RATHER THAN STRONG WINDS OR BLOWING
DUST. AT THIS POINT...GIVEN ALL THESE UNCERTAINTIES...WILL PRETTY
MUCH GO WITH THE CURRENT FORECAST.
&&
.PREVIOUS DISCUSSION...
AS OF 130PM MST...PER LOCAL HI-RES FORECAST MODELS...SOME CONVECTIVE
ACTIVITY HAS BEGUN ABOUT 2 HOURS EARLIER THAN FORECAST. SOME
ISOLATED STORMS IN THE WESTERN ZONES OF ARIZONA AND SOUTHEAST
CALIFORNIA HAVE POPPED UP. NOT SURPRISING AS THIS AREA HAS BEEN
UNDER NEARLY CLEAR SKIES ALL DAY SO THE HEATING AND INSTABILITY HAS
REMAINED IN THESE AREAS. OTHER LOCATIONS THAT HAVE FIRED UP ARE OUT
EAST IN THE WHITE MOUNTAINS AND SOUTH SOUTH AND WEST OF TUCSON. FOR
THE REMAINDER OF TONIGHT...EXPECT ACTIVITY TO CONTINUE INCREASING
OVER THE SOUTHERN PART OF THE STATE WHICH WILL IN TURN GIVE OFF SOME
OUTFLOW AND REDEVELOPMENT ACROSS SOUTHERN MARICOPA COUNTY AND
NORTHWEST PINAL AND SHOULD CREATE AREAS OF BLOWING DUST.
EMBEDDED INVERTED TROUGH MOVING THROUGH SOUTHERN ARIZONA TODAY WILL
BE THE LIFT NEEDED FOR CONVECTIVE ACTIVITY TO TRIGGER. KEEPING A
SOUTHERLY-SOUTHEASTERLY FLOW WITH THE SUBSTANTIAL AMOUNT OF MOISTURE
IN PLACE.../TAPPING INTO BLENDED TPW SATELLITE 1.8 - 2.0 INCHES OF
PWAT/...THE INGREDIENTS ARE AVAILABLE AND READY FOR HEAVY RAIN
PRODUCERS. AS HURRICANE NORBERT CONTINUES A MOSTLY NORTHWARD
TRAJECTORY AND AN INVERTED TROUGH SCOOTS NORTH-NORTHEAST...A VERY
DIFLUENT COLUMN FROM NORTHERN MEXICO THROUGH CENTRAL ARIZONA WILL
REMAIN IN PLACE THROUGH SUNDAY. AS THE FLOW TURNS MORE SOUTHEASTERLY
SUNDAY...WITH INCREASED MOISTURE YET AGAIN...THE BEST WINDOW OF
HEAVY RAINFALL LOOKS TO BE SUNDAY AFTERNOON THROUGH MONDAY MID DAY.
OF COURSE...EACH DAY/S ACTIVITY HIGHLY DEPENDS ON THE PREVIOUS
DAY.../TOO CLOUDED OVER OR THE BOUNDARY LAYER BEING TOO OVER
WORKED/...AND THIS REMAINS THE TRICKY PART OF THE FORECAST. RAINFALL
AMOUNTS AND TIMING CONTINUE TO BE FOCUSED AND FINE TUNED FOR THIS
FORECAST. REGARDLESS OF THE QPF AMOUNTS CERTAIN AREAS RECEIVE...MOST
ALL LOCATIONS ACROSS ARIZONA SHOULD RECEIVE RAIN DURING THIS EVENT.
AFTER MONDAY...OPERATIONAL AND ENSEMBLE FORECAST MODELS HAVE THE
REMNANT LOW FORMERLY KNOWN AS NORBERT ABSORBING INTO A WAVE WHICH
GETS SWEPT IN THE LONGWAVE TROUGH THROUGH THE PACIFIC NORTHWEST.
DIFFERENCES ARISE IN THE TIMING AND SPEED OF THAT TROUGH MOVING
THROUGH ARIZONA INTO THE FOUR CORNERS AND ON TO NEW MEXICO. THE
AIRMASS ACROSS THE SOUTHWEST WILL SLOWLY RECOVER...WITH HEIGHT
CHANGES EVER SO SLIGHT. TEMPERATURES WILL BE SLOW TO CLIMB BACK TO
SEASONAL NORMALS IF THEY EVEN REACH THAT /103F FOR PHOENIX...104F
FOR YUMA/ BY NEXT SATURDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
AFTER A RATHER ACTIVE EVENING...IN SPITE OF INCREASING MOISTURE
THROUGH THE COLUMN...A MORE STABLE AIRMASS AND CONSIDERABLE DEBRIS
CLOUDINESS LEFT OVER FROM TODAY/S CONVECTIVE ACTIVITY WILL LIKELY
ONLY ALLOW SPOTTY SHOWER ACTIVITY TO FORM OVER THE REGION THROUGH
THE REST OF TONIGHT AND MUCH OF SUNDAY...THUS ONLY GOING VCSH AT THE
TAF SITES FOR NOW. ANOTHER WEAK WEATHER DISTURBANCE APPROACHING FROM
THE SOUTH TOMORROW EVENING MAY INCREASE THE CHANCES FOR SHOWER
ACTIVITY A BIT AT THE TAF SITES DURING THAT TIME PERIOD...AND ALLOW
BKN CIGS TO FALL AS LOW AS 6K FT AGL. WINDS TO REMAIN MAINLY OUT OF
A SOUTHEASTERLY DIRECTION THROUGH THE TAF PERIOD
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
LIGHT SHOWER ACTIVITY TO REDEVELOP LATER TONIGHT AND SUNDAY AS
DEEPER MOISTURE MOVES IN FROM THE SOUTHEAST...WITH CIGS FALLING AOB
10K FT AGL. WINDS TO REMAIN MAINLY OUT OF A SOUTHEASTERLY DIRECTION
THROUGH THE TAF PERIOD.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY.
A GRADUAL DRYING TREND WILL COMMENCE TUESDAY AS MOISTURE FROM
HURRICANE NORBERT EXITS THE AREA. HOWEVER...THERE WILL REMAIN AT
LEAST A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS THROUGH
THE END OF THE WEEK. LOW LEVEL MOISTURE WILL BE SLOW TO ERODE
HOWEVER AND GOOD/EXCELLENT RECOVERIES ARE EXPECTED ALL WEEK. AS FOR
WINDS...NO MAJOR WIND EVENTS EXPECTED NEXT WEEK OUTSIDE OF LOCALLY
DRIVEN THUNDERSTORM WINDS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/DEWEY
AVIATION...PERCHA
FIRE WEATHER...LEINS
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
910 PM MST SAT SEP 6 2014
.SYNOPSIS...
MOISTURE WILL CONTINUE TO INCREASE ACROSS THE AREA THIS WEEKEND.
SHOWERS AND THUNDERSTORMS ARE EXPECTED AT TIMES EACH DAY THROUGH
EARLY NEXT WEEK...WITH SOME LOCATIONS POSSIBLY SEEING BRIEF PERIODS
OF HEAVY RAIN. A GRADUAL DRYING TREND IS EXPECTED TO BEGIN NEXT WEEK
AS HIGH PRESSURE SLOWLY REBUILDS OVER THE REGION.
&&
.DISCUSSION...
A RATHER ACTIVE DAY THIS AFTERNOON AND EVENING ACROSS OUR
CWA...ESPECIALLY ACROSS SOUTH-CENTRAL ARIZONA...AS MOISTURE FROM
WEAKENING HURRICANE NORBERT BEGINS TO MOVE NORTHWARD INTO OUR
REGION. AS EXPECTED...WITH PWAT VALUES STILL AOB 1.50 INCH...THE
MAIN ISSUES THIS AFTERNOON AND EVENING WERE STRONG WINDS AND
WIDESPREAD DENSE BLOWING ACROSS THE GREATER PHOENIX AREA AS OUTFLOWS
FROM THUNDERSTORMS OVER PIMA AND PINAL COUNTIES MOVED NORTHWESTWARD
OVER THE REGION. LOCALLY HEAVY RAIN DID FALL IN SOME SPOTS...BUT
THEY HAVE BEEN MAINLY CONFINED SO FAR TO THE SAN TAN VALLEY AREA AND
OVER PORTIONS OF THE NORTH-CENTRAL AND SOUTH-CENTRAL PARTS OF THE
GREATER PHOENIX AREA...WITH MOST LOCATIONS STAYING DRY. ALONG WITH
THE HEAVY RAIN...PARTS OF THE SAN TAN VALLEY AREA ALSO SAW DAMAGING
WINDS...WITH GUSTS AS HIGH AS 60 MPH. ISOLATED THUNDERSTORMS ALSO
BROUGHT STRONG WINDS AND HEAVY DOWNPOURS TO A FEW LOCATIONS ACROSS
LA PAZ COUNTY IN AZ AND IMPERIAL COUNTY IN SE CA.
AS FAR AS THE FORECAST FOR THE REST OF TONIGHT AND INTO EARLY SUNDAY
IS CONCERNED...THE HRRR CONTINUES TO SHOW THE DEVELOPMENT OF SPOTTY
SHOWERS AND THUNDERSTORMS THROUGH THIS PERIOD...WITH ACTIVITY
GRADUALLY WORKING ITS WAY BACK WESTWARD INTO SW AZ AND SE CA...WHICH
IS CONSISTENT WITH CURRENT FORECASTS. ALTHOUGH THE LATEST NAM AND
GFS MODEL SUITES CONTINUE TO PUSH PWATS AOA 2.00 INCHES ON
SUNDAY...THERE IS STILL A FAIR BIT OF UNCERTAINTY ON HOW MUCH/HOW
WIDESPREAD RAINFALL WILL FALL ON SUNDAY...DUE TO THE FACT THAT
LEFTOVER DEBRIS CLOUDS AND A RATHER WORKED-OVER ATMOSPHERE MAY
INHIBIT CONVECTIVE DEVELOPMENT DURING THIS PERIOD. GIVEN THE AMPLE
MOISTURE THAT IS EXPECTED TO BE AVAILABLE...ANY STORMS SHOULD BE
EFFICIENT RAIN PRODUCERS...MAKING THE GREATEST THREAT FROM THESE
STORMS BEING HEAVY RAIN/FLOODING RATHER THAN STRONG WINDS OR BLOWING
DUST. AT THIS POINT...GIVEN ALL THESE UNCERTAINTIES...WILL PRETTY
MUCH GO WITH THE CURRENT FORECAST.
&&
.PREVIOUS DISCUSSION...
AS OF 130PM MST...PER LOCAL HI-RES FORECAST MODELS...SOME CONVECTIVE
ACTIVITY HAS BEGUN ABOUT 2 HOURS EARLIER THAN FORECAST. SOME
ISOLATED STORMS IN THE WESTERN ZONES OF ARIZONA AND SOUTHEAST
CALIFORNIA HAVE POPPED UP. NOT SURPRISING AS THIS AREA HAS BEEN
UNDER NEARLY CLEAR SKIES ALL DAY SO THE HEATING AND INSTABILITY HAS
REMAINED IN THESE AREAS. OTHER LOCATIONS THAT HAVE FIRED UP ARE OUT
EAST IN THE WHITE MOUNTAINS AND SOUTH SOUTH AND WEST OF TUCSON. FOR
THE REMAINDER OF TONIGHT...EXPECT ACTIVITY TO CONTINUE INCREASING
OVER THE SOUTHERN PART OF THE STATE WHICH WILL IN TURN GIVE OFF SOME
OUTFLOW AND REDEVELOPMENT ACROSS SOUTHERN MARICOPA COUNTY AND
NORTHWEST PINAL AND SHOULD CREATE AREAS OF BLOWING DUST.
EMBEDDED INVERTED TROUGH MOVING THROUGH SOUTHERN ARIZONA TODAY WILL
BE THE LIFT NEEDED FOR CONVECTIVE ACTIVITY TO TRIGGER. KEEPING A
SOUTHERLY-SOUTHEASTERLY FLOW WITH THE SUBSTANTIAL AMOUNT OF MOISTURE
IN PLACE.../TAPPING INTO BLENDED TPW SATELLITE 1.8 - 2.0 INCHES OF
PWAT/...THE INGREDIENTS ARE AVAILABLE AND READY FOR HEAVY RAIN
PRODUCERS. AS HURRICANE NORBERT CONTINUES A MOSTLY NORTHWARD
TRAJECTORY AND AN INVERTED TROUGH SCOOTS NORTH-NORTHEAST...A VERY
DIFLUENT COLUMN FROM NORTHERN MEXICO THROUGH CENTRAL ARIZONA WILL
REMAIN IN PLACE THROUGH SUNDAY. AS THE FLOW TURNS MORE SOUTHEASTERLY
SUNDAY...WITH INCREASED MOISTURE YET AGAIN...THE BEST WINDOW OF
HEAVY RAINFALL LOOKS TO BE SUNDAY AFTERNOON THROUGH MONDAY MID DAY.
OF COURSE...EACH DAY/S ACTIVITY HIGHLY DEPENDS ON THE PREVIOUS
DAY.../TOO CLOUDED OVER OR THE BOUNDARY LAYER BEING TOO OVER
WORKED/...AND THIS REMAINS THE TRICKY PART OF THE FORECAST. RAINFALL
AMOUNTS AND TIMING CONTINUE TO BE FOCUSED AND FINE TUNED FOR THIS
FORECAST. REGARDLESS OF THE QPF AMOUNTS CERTAIN AREAS RECEIVE...MOST
ALL LOCATIONS ACROSS ARIZONA SHOULD RECEIVE RAIN DURING THIS EVENT.
AFTER MONDAY...OPERATIONAL AND ENSEMBLE FORECAST MODELS HAVE THE
REMNANT LOW FORMERLY KNOWN AS NORBERT ABSORBING INTO A WAVE WHICH
GETS SWEPT IN THE LONGWAVE TROUGH THROUGH THE PACIFIC NORTHWEST.
DIFFERENCES ARISE IN THE TIMING AND SPEED OF THAT TROUGH MOVING
THROUGH ARIZONA INTO THE FOUR CORNERS AND ON TO NEW MEXICO. THE
AIRMASS ACROSS THE SOUTHWEST WILL SLOWLY RECOVER...WITH HEIGHT
CHANGES EVER SO SLIGHT. TEMPERATURES WILL BE SLOW TO CLIMB BACK TO
SEASONAL NORMALS IF THEY EVEN REACH THAT /103F FOR PHOENIX...104F
FOR YUMA/ BY NEXT SATURDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
QUITE A BIT OF CLOUD COVER ACROSS SE AZ WHICH MAY INHIBIT CONVECTION
UNTIL LATER THIS EVENING. NONETHELESS IT STILL LOOKS LIKE STORMS
WILL FIRE AND MOVE INTO THE METRO THIS EVENING. THE POTENTIAL FOR
BLOWING DUST IS STILL THERE AND I WILL RETAIN THE TEMPO GROUPS FOR
BLDU THROUGH THE EVENING. THERE SHOULD BE SOME SHOWERS IN THE AREA
AS WELL ALTHOUGH I`M NOT CONFIDENT ENOUGH TO INCLUDE PREVAILING RAIN
SHOWERS OR THUNDERSTORMS AT ANY POINT DURING THE TAF PERIOD. MID
CLOUDS SHOULD LINGER THROUGH THE NIGHT INTO LATE SUNDAY MORNING AT
ALL PHOENIX SITES.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
THUNDERSTORMS SHOULD DEVELOP AND APPROACH THE SE CA TAF SITES LATE
IN THE PERIOD...BUT THERE SHOULD BE A THREAT OF BLOWING DUST
BEFOREHAND. VCSH LOOKS INCREASINGLY LIKELY AFTER 12Z AS DEEPER
MOISTURE MOVES INTO THE AREA.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY.
A GRADUAL DRYING TREND WILL COMMENCE TUESDAY AS MOISTURE FROM
HURRICANE NORBERT EXITS THE AREA. HOWEVER...THERE WILL REMAIN AT
LEAST A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS THROUGH
THE END OF THE WEEK. LOW LEVEL MOISTURE WILL BE SLOW TO ERODE
HOWEVER AND GOOD/EXCELLENT RECOVERIES ARE EXPECTED ALL WEEK. AS FOR
WINDS...NO MAJOR WIND EVENTS EXPECTED NEXT WEEK OUTSIDE OF LOCALLY
DRIVEN THUNDERSTORM WINDS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/DEWEY
AVIATION...LEINS
FIRE WEATHER...LEINS
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
1040 PM PDT SAT SEP 6 2014
...AVIATION DISCUSSION UPDATED...
.SYNOPSIS...
INCREASING MOISTURE FROM TROPICAL CYCLONE NORBERT WILL BRING A
CHANCE OF SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS TO MUCH OF
LOS ANGELES AND VENTURA COUNTIES SUNDAY THROUGH MONDAY...AND TO
SANTA BARBARA COUNTY SUNDAY NIGHT INTO MONDAY MORNING. A SLIGHT
CHANCE OF THUNDERSTORMS WILL LINGER MONDAY EVENING IN THE
MOUNTAINS OF VENTURA AND LOS ANGELES COUNTIES AND IN THE ANTELOPE
VALLEY. DRIER AND COOLER WEATHER CAN BE EXPECTED TUESDAY AND
WEDNESDAY...FOLLOWED BY WARMING BY THE END OF THE WEEK.
&&
.UPDATE...
MOISTURE IS SPILLING INTO SOUTHERN CALIFORNIA FROM HURRICANE
NORBERT TO THE SOUTH. KNKX RAOB DATA INDICATE PERCIPITABLE WATER
VALUES AROUND 1.36 INCH...OR 158 PERCENT OF NORMAL. MODELS ARE
DIVERGING A BIT THROUGH SUNDAY EVENING...SOME KEEPING LOS ANGELES
AND VENTURA COUNTIES DRIER THROUGH SUNDAY MORNING. THE LATEST
NAM-WRF SOLUTIONS ARE LESS AGGRESSIVE WITH THE MOISTURE MOVING
NORTHWARD...BUT THE LATEST RAP SOLUTIONS SUGGEST MOISTURE
REMAINING FAIRLY PROGRESSIVE. NAM-WRF SOLUTIONS SEEMS A BIT
UNREALISTIC...BLOWING UP DRIER AIR OVER THE SANTA MONICA BAY. THE
FORECAST WILL REMAIN IN TACT FOR NOW UNTIL MORE DATA ARRIVES.
&&
.PREV DISCUSSION...
SHORT TERM...FOR THE REMAINDER OF THE SHORT TERM...ALL EYES WILL
BE ON HURRICANE NORBERT. AS OF 2 PM PDT...THE CENTER OF NORBERT
WAS LOCATED AROUND 530 MILES SOUTH OF SAN DIEGO...AND CONTINUES TO
TRACK TO THE NORTHWEST AT AROUND 8 MILES PER HOUR. THE LATEST
HURRICANE CENTER BULLETIN AS OF 2 PM HAS DOWNGRADED NORBERT TO A
CATEGORY 2 HURRICANE...WITH SUSTAINED WINDS AT 105 MPH. AS NORBERT
CONTINUES TO TRACK TO THE NORTHWEST INTO RELATIVELY COOLER SEA
SURFACE TEMPERATURES...THE STORM IS EXPECTED TO CONTINUE WEAKENING
OVER THE NEXT 24 TO 48 HOURS. THE CENTER OF THE DISSIPATED CYCLONE
IS THEN EXPECTED TO MAKE LANDFALL ACROSS NORTHERN BAJA AS A
TROPICAL DEPRESSION BY TUESDAY NIGHT OR WEDNESDAY MORNING.
THE MAIN IMPACTS OF NORBERT FOR OUR FORECAST AREA WILL BE INCREASING
MOISTURE WITH A THREAT OF SHOWERS AND THUNDERSTORMS...ALONG WITH
ELEVATED SURF AND DANGEROUS RIP CURRENTS. HURRICANE NORBERT HAS
A VERY RICH MOISTURE SUPPLY WITH SATELLITE ESTIMATING A LARGE AREA
OF PRECIPITABLE WATER VALUES OF AROUND 3 INCHES! ON SUNDAY AND
MONDAY...MOISTURE LEVELS WILL BE ON THE INCREASE ACROSS OUR FORECAST
AREA...WITH PRECIPITABLE WATER VALUES PEAKING AT AROUND 2 INCHES
BY MONDAY. THE THREAT OF SHOWERS AND THUNDERSTORMS WILL BEGIN ACROSS
LOS ANGELES COUNTY AND THE ADJACENT COASTAL WATERS ON SUNDAY MORNING.
THE MOIST SOUTHEAST FLOW WILL THEN SHIFT THE THREAT OF SHOWERS AND
THUNDERSTORMS TO THE NORTHWEST ACROSS VENTURA AND SANTA BARBARA
COUNTIES (ALONG WITH THE ADJACENT COASTAL WATERS) SUNDAY AFTERNOON
INTO SUNDAY NIGHT. THE GREATEST THREAT OF STORMS WILL BE ACROSS THE
MOUNTAINS AND ANTELOPE VALLEY WHERE POPS ARE IN THE 40 PERCENT RANGE.
HOWEVER...THERE IS A 20 PERCENT CHANCE OF SHOWERS AND THUNDERSTORMS
FOR REMAINING COASTAL/VALLEY LOCATIONS. IMPRESSIVE SURGE OF LOW LEVEL
MOISTURE AS 850 MB DEWPOINTS CLIMB TO BETWEEN 13 AND 15 DEGREES
CELSIUS DURING EVENT. IN ADDITION...ADDED THE SLIGHT CHANCE OF
THUNDERSTORMS FOR ALL AREAS AS MODELS ARE SHOWING A RATHER BROAD
AREA OF K-INDEX VALUES BETWEEN 35 AND 40.
DUE TO THE ABUNDANT MOISTURE ASSOCIATED WITH THIS SYSTEM...THE
GREATEST THREAT WITH ANY STORMS THAT DEVELOP WILL BE THE POTENTIAL
FOR HEAVY RAINFALL. THE BIG QUESTION MARK AT THIS POINT WILL BE
WHETHER OR NOT WE GET ENOUGH BREAKS IN CLOUD COVERAGE TO ALLOW
FOR SOME DAYTIME HEATING TO ADEQUATELY DESTABILIZE THE ATMOSPHERE.
IF WE BEGIN TO SEE THE POTENTIAL FOR SOME BREAKS IN CLOUD COVERAGE...
A FLASH FLOOD WATCH MAY NEED TO BE CONSIDERED FOR PORTIONS OF THE
MOUNTAINS AND ANTELOPE VALLEY DURING THE NEXT COUPLE OF DAYS. THE
AMOUNT OF CLOUD COVERAGE WILL ALSO GREATLY IMPACT MAX TEMPERATURES
ON SUNDAY. WITH EVEN WEAKER ONSHORE GRADIENTS EXPECTED ON
SUNDAY...THERE WILL BE THE POTENTIAL FOR VERY WARM AND HUMID
CONDITIONS ACROSS THE REGION. HOWEVER...CURRENT THINKING IS THAT
CLOUD COVERAGE WILL HELP KEEP MOST OF THE VALLEYS IN THE 90S ON
SUNDAY. HOWEVER...THE INCREASED HUMIDITY WILL COULD CERTAINLY BRING
HEAT INDEX VALUES OVER 100 DEGREES WITH THE POTENTIAL FOR VERY WARM
AND MUGGY CONDITIONS SUNDAY NIGHT. AN UPPER LEVEL TROUGH IS EXPECTED
TO BEGIN SHIFTING NORBERT MOISTURE TO THE EAST ON TUESDAY WITH
DRYING TREND ACROSS THE REGION.
LONG TERM...AN UPPER RIDGE OF HIGH PRESSURE WILL BEGIN TO BRING A
WARMING TREND DURING THE EXTENDED PERIOD. SHALLOW MARINE LAYER
DURING PERIOD WITH ANY LOW CLOUDS AND FOG CONFINED TO COASTAL
AREAS. DRY WEATHER THROUGH PERIOD.
&&
.AVIATION...07/06Z.
NORTH OF POINT CONCEPTION...MODERATE CONFIDENCE THAT LIFR TO IFR
CONDITIONS WILL DEVELOP AT COASTAL SITES 04Z-11Z...WITH THE BEST
CHANCE OF LIFR TO IFR CONDITIONS BETWEEN 08Z AND 17Z. OTHERWISE AND
ELSEWHERE VFR CONDITIONS WILL PREVAIL
SOUTH OF POINT CONCEPTION...LOW TO MODERATE CONFIDENCE DUE TO
MOISTURE FROM HURRICANE NORBERT SPREADING NORTH. MID LEVEL CLOUD
COVER SHOULD HELP TO RETARD SURFACE CLOUD DEVELOPMENT. A TWENTY
PERCENT CHANCE OF IFR-MVFR CONDITIONS AT COASTAL SITES AND ADJACENT
VALLEYS 08Z-16Z. AFTER 15Z...THERE IS A SLIGHT CHANCE OF SHOWERS AT
LOS ANGELES COUNTY SITES... WITH A SLIGHT CHANCE OF THUNDERSTORMS
AFTER 18Z. OTHERWISE AND ELSEWHERE VFR CONDITIONS WILL PREVAIL.
KLAX...LOW TO MODERATE CONFIDENCE DUE TO MOISTURE FROM HURRICANE
NORBERT SPREADING NORTH. MID LEVEL CLOUD COVER SHOULD HELP TO
RETARD SURFACE CLOUD DEVELOPMENT. A TWENTY PERCENT CHANCE OF
IFR-MVFR CONDITIONS 08Z-16Z. DURING THE PERIOD 20Z-05Z...THERE IS A
SLIGHT CHANCE OF THUNDERSTORMS. OTHERWISE VFR CONDITIONS WILL
PREVAIL.
KBUR...LOW TO MODERATE CONFIDENCE DUE TO MOISTURE FROM HURRICANE
NORBERT SPREADING NORTH. MID LEVEL CLOUD COVER SHOULD HELP TO
RETARD SURFACE CLOUD DEVELOPMENT. A TEN PERCENT CHANCE OF MVFR
CONDITIONS 08Z-16Z. AFTER 18Z...THERE IS A SLIGHT CHANCE OF
THUNDERSTORMS. OTHERWISE VFR CONDITIONS WILL PREVAIL.
&&
.MARINE...06/900 PM.
SMALL CRAFT ADVISORY HAS BEEN EXTENDED FOR THE OUTER WATERS. HIGH
CONFIDENCE IN NORTHWEST WINDS GUSTING TO 25 KNOTS THROUGH EARLY
MONDAY MORNING. THE STRONGEST WINDS ARE EXPECTED BETWEEN POINT
CONCEPTION AND SAN NICOLAS ISLAND.FOR THE INNER WATERS...CONDITIONS
ARE ANTICIPATED TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS
THROUGH MID-WEEK. THE EFFECTS OF HURRICANE NORBERT WILL MOVE OVER
THE AREA THROUGH MONDAY. ISOLATED SHOWERS AND THUNDERSTORM WILL
LIKELY IMPACT THE COASTAL WATERS BETWEEN SUNDAY AND MONDAY.
CONFIDENCE IS LOW TO MODERATE IN CONVECTIVE STORMS DEVELOPING.
A MARINE WEATHER STATEMENT HAS BEEN ISSUED.
&&
.BEACHES...06/900 PM.
A BEACH HAZARD STATEMENT WILL BE CONTINUED AS THE SWELL PERIOD
WILL SHORTEN THROUGH SUNDAY AS THE SWELLS FROM HURRICANE NORBERT
ARRIVE. THE SOUTHERN HEMISPHERE SWELL WILL CONTINUE TO SLOWLY
DIMINISH IN HEIGHT AND PERIOD AND BE REPLACED A SE SWELL FROM
HURRICANE NORBERT. MODERATE TO HIGH CONFIDENCE IN THIS SWELL
ARRIVING AS FORECAST...AND THE PERIOD IS LIKELY TO BE ON THE
SHORTER SIDE AT AROUND 11 SECONDS. ELEVATED SURF AND STRONG RIP
CURRENTS ARE EXPECTED TO PERSIST THROUGH LATE MONDAY NIGHT. THE
CURRENTS MAY IN FACT CONTINUE THROUGH TUESDAY ALTHOUGH SWELL AND
SURF WILL CONTINUE TO SUBSIDE.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
BEACH HAZARDS STATEMENT (SEE LAXCFWLOX).
MARINE WEATHER STATEMENT (SEE LAXMWSLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
&&
$$
PUBLIC...HALL
AVIATION...KJ
MARINE/BEACHES...HALL
SYNOPSIS...SIRARD
WWW.WEATHER.GOV/LOSANGELES
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
919 PM PDT SAT SEP 6 2014
.SYNOPSIS...
INCREASING MOISTURE FROM TROPICAL CYCLONE NORBERT WILL BRING A
CHANCE OF SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS TO MUCH OF
LOS ANGELES AND VENTURA COUNTIES SUNDAY THROUGH MONDAY...AND TO
SANTA BARBARA COUNTY SUNDAY NIGHT INTO MONDAY MORNING. A SLIGHT
CHANCE OF THUNDERSTORMS WILL LINGER MONDAY EVENING IN THE
MOUNTAINS OF VENTURA AND LOS ANGELES COUNTIES AND IN THE ANTELOPE
VALLEY. DRIER AND COOLER WEATHER CAN BE EXPECTED TUESDAY AND
WEDNESDAY...FOLLOWED BY WARMING BY THE END OF THE WEEK.
&&
.UPDATE...
MOISTURE IS SPILLING INTO SOUTHERN CALIFORNIA FROM HURRICANE
NORBERT TO THE SOUTH. KNKX RAOB DATA INDICATE PERCIPITABLE WATER
VALUES AROUND 1.36 INCH...OR 158 PERCENT OF NORMAL. MODELS ARE
DIVERGING A BIT THROUGH SUNDAY EVENING...SOME KEEPING LOS ANGELES
AND VENTURA COUNTIES DRIER THROUGH SUNDAY MORNING. THE LATEST
NAM-WRF SOLUTIONS ARE LESS AGGRESSIVE WITH THE MOISTURE MOVING
NORTHWARD...BUT THE LATEST RAP SOLUTIONS SUGGEST MOISTURE
REMAINING FAIRLY PROGRESSIVE. NAM-WRF SOLUTIONS SEEMS A BIT
UNREALISTIC...BLOWING UP DRIER AIR OVER THE SANTA MONICA BAY. THE
FORECAST WILL REMAIN IN TACT FOR NOW UNTIL MORE DATA ARRIVES.
&&
.PREV DISCUSSION...
SHORT TERM...FOR THE REMAINDER OF THE SHORT TERM...ALL EYES WILL
BE ON HURRICANE NORBERT. AS OF 2 PM PDT...THE CENTER OF NORBERT
WAS LOCATED AROUND 530 MILES SOUTH OF SAN DIEGO...AND CONTINUES TO
TRACK TO THE NORTHWEST AT AROUND 8 MILES PER HOUR. THE LATEST
HURRICANE CENTER BULLETIN AS OF 2 PM HAS DOWNGRADED NORBERT TO A
CATEGORY 2 HURRICANE...WITH SUSTAINED WINDS AT 105 MPH. AS NORBERT
CONTINUES TO TRACK TO THE NORTHWEST INTO RELATIVELY COOLER SEA
SURFACE TEMPERATURES...THE STORM IS EXPECTED TO CONTINUE WEAKENING
OVER THE NEXT 24 TO 48 HOURS. THE CENTER OF THE DISSIPATED CYCLONE
IS THEN EXPECTED TO MAKE LANDFALL ACROSS NORTHERN BAJA AS A
TROPICAL DEPRESSION BY TUESDAY NIGHT OR WEDNESDAY MORNING.
THE MAIN IMPACTS OF NORBERT FOR OUR FORECAST AREA WILL BE INCREASING
MOISTURE WITH A THREAT OF SHOWERS AND THUNDERSTORMS...ALONG WITH
ELEVATED SURF AND DANGEROUS RIP CURRENTS. HURRICANE NORBERT HAS
A VERY RICH MOISTURE SUPPLY WITH SATELLITE ESTIMATING A LARGE AREA
OF PRECIPITABLE WATER VALUES OF AROUND 3 INCHES! ON SUNDAY AND
MONDAY...MOISTURE LEVELS WILL BE ON THE INCREASE ACROSS OUR FORECAST
AREA...WITH PRECIPITABLE WATER VALUES PEAKING AT AROUND 2 INCHES
BY MONDAY. THE THREAT OF SHOWERS AND THUNDERSTORMS WILL BEGIN ACROSS
LOS ANGELES COUNTY AND THE ADJACENT COASTAL WATERS ON SUNDAY MORNING.
THE MOIST SOUTHEAST FLOW WILL THEN SHIFT THE THREAT OF SHOWERS AND
THUNDERSTORMS TO THE NORTHWEST ACROSS VENTURA AND SANTA BARBARA
COUNTIES (ALONG WITH THE ADJACENT COASTAL WATERS) SUNDAY AFTERNOON
INTO SUNDAY NIGHT. THE GREATEST THREAT OF STORMS WILL BE ACROSS THE
MOUNTAINS AND ANTELOPE VALLEY WHERE POPS ARE IN THE 40 PERCENT RANGE.
HOWEVER...THERE IS A 20 PERCENT CHANCE OF SHOWERS AND THUNDERSTORMS
FOR REMAINING COASTAL/VALLEY LOCATIONS. IMPRESSIVE SURGE OF LOW LEVEL
MOISTURE AS 850 MB DEWPOINTS CLIMB TO BETWEEN 13 AND 15 DEGREES
CELSIUS DURING EVENT. IN ADDITION...ADDED THE SLIGHT CHANCE OF
THUNDERSTORMS FOR ALL AREAS AS MODELS ARE SHOWING A RATHER BROAD
AREA OF K-INDEX VALUES BETWEEN 35 AND 40.
DUE TO THE ABUNDANT MOISTURE ASSOCIATED WITH THIS SYSTEM...THE
GREATEST THREAT WITH ANY STORMS THAT DEVELOP WILL BE THE POTENTIAL
FOR HEAVY RAINFALL. THE BIG QUESTION MARK AT THIS POINT WILL BE
WHETHER OR NOT WE GET ENOUGH BREAKS IN CLOUD COVERAGE TO ALLOW
FOR SOME DAYTIME HEATING TO ADEQUATELY DESTABILIZE THE ATMOSPHERE.
IF WE BEGIN TO SEE THE POTENTIAL FOR SOME BREAKS IN CLOUD COVERAGE...
A FLASH FLOOD WATCH MAY NEED TO BE CONSIDERED FOR PORTIONS OF THE
MOUNTAINS AND ANTELOPE VALLEY DURING THE NEXT COUPLE OF DAYS. THE
AMOUNT OF CLOUD COVERAGE WILL ALSO GREATLY IMPACT MAX TEMPERATURES
ON SUNDAY. WITH EVEN WEAKER ONSHORE GRADIENTS EXPECTED ON
SUNDAY...THERE WILL BE THE POTENTIAL FOR VERY WARM AND HUMID
CONDITIONS ACROSS THE REGION. HOWEVER...CURRENT THINKING IS THAT
CLOUD COVERAGE WILL HELP KEEP MOST OF THE VALLEYS IN THE 90S ON
SUNDAY. HOWEVER...THE INCREASED HUMIDITY WILL COULD CERTAINLY BRING
HEAT INDEX VALUES OVER 100 DEGREES WITH THE POTENTIAL FOR VERY WARM
AND MUGGY CONDITIONS SUNDAY NIGHT. AN UPPER LEVEL TROUGH IS EXPECTED
TO BEGIN SHIFTING NORBERT MOISTURE TO THE EAST ON TUESDAY WITH
DRYING TREND ACROSS THE REGION.
LONG TERM...AN UPPER RIDGE OF HIGH PRESSURE WILL BEGIN TO BRING A
WARMING TREND DURING THE EXTENDED PERIOD. SHALLOW MARINE LAYER
DURING PERIOD WITH ANY LOW CLOUDS AND FOG CONFINED TO COASTAL
AREAS. DRY WEATHER THROUGH PERIOD.
&&
.AVIATION...07/0052Z.
NORTH OF POINT CONCEPTION...LIFR TO IFR CONDITIONS WILL SPREAD IN
BETWEEN 04Z AND 11Z...WITH THE BEST CHANCE OF LIFR TO IFR CONDITIONS
BETWEEN 08Z AND 16Z. VFR CONDITIONS SHOULD REDEVELOP BETWEEN 16Z AND
17Z.
SOUTH OF POINT CONCEPTION...LOWER CONFIDENCE DUE TO MOISTURE FROM
HURRICANE NORBERT SPREADING NORTH. VFR CONDITIONS ARE EXPECTED AT
ALL TERMINALS EXCEPT FOR A CHANCE OF SUB-VFR CONDITIONS MAINLY
BETWEEN 08Z AND 16Z. AFTER 15Z...THERE IS A SLIGHT CHANCE OF SHOWERS
OVER THE COASTAL AND VALLEY TERMINALS.
KLAX...VFR CONDITIONS ARE EXPECTED THROUGH AT LEAST 08Z. THERE IS A
50 PERCENT CHANCE OF MVFR CONDITIONS BETWEEN 13Z AND 16Z. THERE IS
20 PERCENT CHANCE OF LIFR CONDITIONS BETWEEN 08Z AND 16Z. THERE IS A
20 PERCENT CHANCE OF SHOWERS AND THUNDERSTORMS...MAINLY AFTER 16Z.
KBUR...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD. THERE IS A
20 PERCENT OF SHOWERS AND THUNDERSTORMS...MAINLY AFTER 19Z.
&&
.MARINE...06/900 PM.
SMALL CRAFT ADVISORY HAS BEEN EXTENDED FOR THE OUTER WATERS. HIGH
CONFIDENCE IN NORTHWEST WINDS GUSTING TO 25 KNOTS THROUGH EARLY
MONDAY MORNING. THE STRONGEST WINDS ARE EXPECTED BETWEEN POINT
CONCEPTION AND SAN NICOLAS ISLAND.FOR THE INNER WATERS...CONDITIONS
ARE ANTICIPATED TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS
THROUGH MID-WEEK. THE EFFECTS OF HURRICANE NORBERT WILL MOVE OVER
THE AREA THROUGH MONDAY. ISOLATED SHOWERS AND THUNDERSTORM WILL
LIKELY IMPACT THE COASTAL WATERS BETWEEN SUNDAY AND MONDAY.
CONFIDENCE IS LOW TO MODERATE IN CONVECTIVE STORMS DEVELOPING.
A MARINE WEATHER STATEMENT HAS BEEN ISSUED.
&&
.BEACHES...06/900 PM.
A BEACH HAZARD STATEMENT WILL BE CONTINUED AS THE SWELL PERIOD
WILL SHORTEN THROUGH SUNDAY AS THE SWELLS FROM HURRICANE NORBERT
ARRIVE. THE SOUTHERN HEMISPHERE SWELL WILL CONTINUE TO SLOWLY
DIMINISH IN HEIGHT AND PERIOD AND BE REPLACED A SE SWELL FROM
HURRICANE NORBERT. MODERATE TO HIGH CONFIDENCE IN THIS SWELL
ARRIVING AS FORECAST...AND THE PERIOD IS LIKELY TO BE ON THE
SHORTER SIDE AT AROUND 11 SECONDS. ELEVATED SURF AND STRONG RIP
CURRENTS ARE EXPECTED TO PERSIST THROUGH LATE MONDAY NIGHT. THE
CURRENTS MAY IN FACT CONTINUE THROUGH TUESDAY ALTHOUGH SWELL AND
SURF WILL CONTINUE TO SUBSIDE.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
BEACH HAZARDS STATEMENT (SEE LAXCFWLOX).
MARINE WEATHER STATEMENT (SEE LAXMWSLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
&&
$$
PUBLIC...HALL
AVIATION...HALL
MARINE/BEACHES...HALL
SYNOPSIS...SIRARD
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION...CORRECTED
NWS JACKSONVILLE FL
530 AM EDT SUN SEP 7 2014
...FLOOD THREAT PERSISTS IN THE SUWANNEE VALLEY THROUGH EARLY THIS
WEEK...
.CURRENTLY...
EARLY MORNING SURFACE ANALYSIS DEPICTS A LOW PRESSURE TROUGH
EXTENDING FROM COASTAL SOUTHEAST GEORGIA SOUTHWESTWARD TO THE
NORTHEAST GULF OF MEXICO. A COLD FRONT IS EXITING THE MID-ATLANTIC
COAST AND THE TENNESSEE VALLEY REGION...AND IS ENTERING THE
SOUTHEASTERN STATES. MEANWHILE...THE AXIS OF ATLANTIC RIDGING
EXTENDS ACROSS THE FLORIDA PENINSULA. ALOFT...WEAK CYCLONIC FLOW
PREVAILS OVER OUR REGION...IN BETWEEN RIDGES OVER THE WESTERN AND
CENTRAL ATLANTIC AND THE DESERT SOUTHWEST. SLOW MOVING NOCTURNAL
CONVECTION HAS ONCE AGAIN FIRED ALONG THE SURFACE TROUGH OVER THE
SUWANNEE VALLEY...WITH THE SOUTHERN HALF OF COLUMBIA COUNTY ONCE
AGAIN BEING THE TARGET AREA OF THE HEAVIEST RAINS. DOPPLER RADAR
ESTIMATES DURING THE PAST 24 HOURS DEPICT A SWATH OF 5 TO 8 INCH
RAINS IN SOUTHERN COLUMBIA AND FAR EASTERN SUWANEE COUNTIES...WITH A
BULLS-EYE OF 9 TO 14 INCH TOTALS JUST SOUTH OF LAKE CITY. WITH HEAVY
DOWNPOURS...SOME CONTAINING RAINFALL RATES IN EXCESS OF 2 INCHES PER
HOUR...FALLING OVER THESE SATURATED GROUND CONDITIONS...A FLASH
FLOOD WARNING HAS BEEN ISSUED FOR CENTRAL COLUMBIA COUNTY THROUGH 7
AM. ELSEWHERE...SCATTERED TO NUMEROUS SHOWERS ARE ALSO OVERSPREADING
THE REMAINDER OF NORTHEAST AND NORTH CENTRAL FLORIDA...AS WELL AS
COASTAL SOUTHEAST GEORGIA. BENEATH EXTENSIVE MULTI-LAYERED
CLOUDINESS...TEMPERATURES AND DEWPOINTS AT 09Z WERE GENERALLY IN THE
MID 70S.
.NEAR TERM (TODAY AND TONIGHT)...
SHORT TERM HI-RESOLUTION MODELS SUCH AS THE 03Z HRRR HAVE
INITIALIZED THE NOCTURNAL CONVECTIVE BURST OVER THE SUWANNEE
VALLEY...AND THIS MODEL SUGGESTS THAT ACTIVITY WILL TRANSITION
SOUTH AND EASTWARD INTO NORTH CENTRAL AND NORTHEAST FLORIDA DURING
THE MORNING HOURS. A FRONTAL BOUNDARY WILL APPROACH SOUTHEAST GA
LATER TODAY...WHICH SHOULD LIFT LOW PRESSURE SLOWLY NORTHEASTWARD
INTO COASTAL SOUTHEAST GA. SIMILAR TO YESTERDAY...MORNING
CONVECTION OVER NORTHEAST FL AND COASTAL SOUTHEAST GA WILL LIKELY
FADE BY THE LATE MORNING HOURS. HOWEVER...WITH FORCING ASSOCIATED
WITH THE FRONT ARRIVING INTO OUR REGION DURING PEAK
HEATING...ANOTHER ROUND OF LOCALLY HEAVY DOWNPOURS AND EMBEDDED
THUNDERSTORMS APPEARS LIKELY DURING THE LATE AFTERNOON AND EARLY
EVENING HOURS OVER MUCH OF OUR REGION. CATEGORICAL POPS WERE THUS
INSERTED FOR MUCH OF SOUTHEAST GA...WHERE THE GREATEST MOISTURE
CONVERGENCE WILL BE LOCATED LATER TODAY. SINCE WE EXPECT A BREAK
IN THE HEAVY DOWNPOURS OVER THE SUWANNEE VALLEY LATER THIS
MORNING...WE WILL HOLD OFF ON ISSUING ANY LARGE SCALE FLOOD
WATCHES AT THIS TIME. HOWEVER...LOCALIZED FLOODING WILL BE A
GROWING CONCERN REGION-WIDE AS TROPICAL MOISTURE REMAINS IN PLACE
DURING AT THE LEAST THE NEXT FEW DAYS...AND WEAK STEERING FLOW
ALOFT RESULTS IN CONTINUED SLOW MOVEMENT OF CONVECTION. SOME
BREAKS IN THE CLOUDS OVER INTERIOR SOUTHEAST GEORGIA THIS MORNING
WILL ALLOW TEMPERATURES TO RISE TO NEAR 90 BEFORE CLOUDS AND
RAINFALL DEVELOP THIS AFTERNOON. ELSEWHERE...ABUNDANT CLOUDS WILL
KEEP HIGHS IN THE MID/UPPER 80S.
WIDESPREAD RAINS MAY BE SLOW TO DEPART COASTAL SOUTHEAST GA
TONIGHT...AS LOW PRESSURE BEGINS TO LIFT SLOWLY NORTHEASTWARD
AHEAD OF THE STALLING FRONTAL BOUNDARY. OTHERWISE...SHOWERS SHOULD
DECREASE IN COVERAGE OVER NORTHEAST AND NORTH CENTRAL FL DURING
THE EARLY EVENING HOURS. A BAND OF CONVECTION MAY DEVELOP OVER THE
NORTHEAST GULF OF MEXICO DURING THE PREDAWN HOURS ON MONDAY...AND
THIS ACTIVITY COULD IMPACT PORTIONS OF NORTH CENTRAL FL BEFORE
SUNRISE. THE TROPICAL AIR MASS WILL KEEP LOWS IN THE 70S REGION-
WIDE.
.SHORT TERM (MONDAY THROUGH WEDNESDAY)...
ABUNDANT TROPICAL MOISTURE WILL PERSIST OVER OUR REGION ON MONDAY
AS LOW PRESSURE LIFTS NORTHEASTWARD ALONG THE GA/SC COASTS.
MEANWHILE...A STALLED FRONTAL BOUNDARY WILL RESIDE JUST WEST OF
OUR REGION...WITH MODEL SOUNDINGS DEPICTING DEEP W/SW FLOW
PERSISTING ALONG A TRAILING TROUGH FROM THE LOW PRESSURE CENTER.
SIGNIFICANT MOISTURE CONVERGENCE WILL REMAIN IN PLACE ALONG THIS
TROUGH AND AHEAD OF THE FRONT...WITH ABUNDANT CLOUDS AND ANOTHER
ROUND OF SCATTERED TO NUMEROUS THUNDERSTORMS EXPECTED TO IMPACT
MUCH OF OUR REGION. ADDITIONAL WIDESPREAD RAINS OF 1 TO 2 INCHES
WITH LOCALLY HIGHER TOTALS WILL KEEP THE THREAT OF FLOODING IN
PLACE...PARTICULARLY IN URBAN AND COASTAL LOCATIONS DURING THE
AFTERNOON AND EVENING HOURS. WIDESPREAD CLOUDS AND A RELATIVELY
EARLY START TO CONVECTION WILL KEEP HIGHS IN THE UPPER 80S.
RAINFALL SHOULD DIMINISH OVER MOST OF THE REGION DURING THE EARLY
EVENING HOURS ON MON...WITH MUGGY LOWS IN THE 70S EXPECTED.
TUE...A WAKE TROUGH WILL LINGER OVER THE FORECAST AREA AS THE
PARENT LOW TRACKS NE ALONG THE ATLANTIC SEABOARD. THIS BOUNDARY
COMBINED WITH A LINGERING PLUME OF HIGHER MOISTURE WILL SLOWLY
SHIFT SOUTHWARD OVER NE FL TUE AFTN...AND PROVIDE A FOCUS ANOTHER
ROUND OF NUMEROUS SHOWERS AND TSTORMS. DRIER AND MORE STABLE AIR
WILL GRADUALLY INFILTRATE OVER SE GA THROUGH TUE AND ADVERTISED
LOWER RAIN CHANCES IN THE 40-50% RANGE...WITH 60% OVER NE FL
DURING THE AFTN/EVENING. PRECIP WILL SHIFT TO THE ESE INTO THE
EVENING HOURS WILL DECREASING IN COVERAGE AND INTENSITY WITH THE
LOSS OF DAYTIME INSTABILITY. HIGH TEMPS TUE WILL RANGE IN THE
MID/UPPER 80S INLAND TO LOW/MID 80S COAST WITH OVERNIGHT LOWS TUE
NIGHT FALLING INTO THE UPPER 60S TO LOW 70S INLAND WITH DRIER AIR
IN PLACE AND CLEARING SKIES. PATCHY LATE NIGHT FOG POSSIBLE.
WED...LOWER RAIN CHANCES WITH STACKED HIGH PRESSURE OVER THE
AREA...HOWEVER LINGERING MOISTURE PLUME WILL CONTINUE TO SUPPORT A
CHANCE OF MAINLY AFTN/EARLY EVENING SHOWERS AND ISOLATED TSTORMS
WITH THE HIGHEST CHANCES OVER INLAND NE FL. RAIN CHANCES RANGE
FROM 30% OVER INLAND SE GA TO 35% OVER INLAND NE FL. WARM UPPER
LEVEL TEMPS AND SUBSIDENCE WILL KEEP THUNDERSTORMS TAME AND SPARSE
IN COVERAGE...SO ONLY INDICATED ISOLATED TSTORMS IN THE FORECAST.
TEMPS WILL WARM INTO THE LOW 90S INLAND TO MID 80S COAST WITH LOWS
COOLING INTO THE LOW 70S INLAND/MID 70S COAST WED NIGHT.
.LONG TERM (THURSDAY THROUGH SUNDAY)...
THU & FRI MEAN LAYER 1000-500 MB RIDGE AXIS WILL EXTEND ACROSS NE
FL AND SE GA WITH PWATS FALLING INTO THE 1.5-1.9 RANGE WITH THE
HIGHER VALUES OVER SE GA. ADVERTISED NEAR TO SLIGHTLY BELOW RAIN
CHANCES BOTH DAYS IN THE 30-40% RANGE WITH A DIURNAL PATTERN AND
LIGHT SOUTH STEERING FLOW WHICH WILL ENABLE BOTH SEA BREEZES TO
PUSH INLAND AND FOCUS A MERGER BETWEEN THE ST JOHNS RIVER BASIN
AND INTERSTATE 75. HIGHS WILL BE NEAR TO ABOVE NORMAL GIVEN
STACKED SUBSIDENCE WITH UPPER 80S TO LOW 90S INLAND TO MID 80S
COAST...WITH MILD LOWS RANGING IN THE 70S.
SAT & SUN RAIN CHANCES INCREASE AS A FRONTAL ZONE STALLS OVER GA
AND A TROPICAL WAVE ROTATES NORTHWARD FROM THE BAHAMAS. PWATS
INCREASE TO OVER 2 INCHES BY SUNDAY. THUS INCREASED RAIN CHANCES
INTO THE 40-50% RANGE...BUT IF MODEL PERSISTENCE
CONTINUES...LIKELY POPS MAY BE NEEDED NEXT WEEKEND (60-70%). TEMPS
WILL BEGIN TO FALL BACK TO NEAR TO SLIGHTLY BELOW CLIMO FOR HIGHS
GIVEN INCREASED CLOUD COVER AND LOWER THICKNESSES WITH HIGHS IN
THE MID/UPPER 80S AND MUGGY LOWS CONTINUING IN THE 70S.
&&
.AVIATION...
PERIODS OF SUB-VFR CONDITIONS WILL CONTINUE THROUGHOUT THE
DAY...WITH TEMPO GROUPS USED FOR IFR VISIBILITIES AND MVFR CIGS
THROUGH AROUND 12Z. ANOTHER ROUND OF POTENTIAL IFR CONDITIONS IS
POSSIBLE AT THE TERMINALS THIS AFTERNOON AS WEAK LOW PRESSURE OVER
OUR REGION DEVELOPS NUMEROUS SLOW MOVING SHOWERS AND THUNDERSTORMS
AFTER 15Z. OUTSIDE OF HEAVIER SHOWERS AND
THUNDERSTORMS...SOUTHWEST WINDS WILL INCREASE TO NEAR 10 KNOTS
THIS AFTERNOON AT THE REGIONAL TERMINALS.
&&
.MARINE...
WEAK LOW PRESSURE WILL BE SLOW TO MOVE AWAY FROM OUR REGION
THROUGH MONDAY...WHILE A FRONTAL BOUNDARY STALLS JUST NORTHWEST OF
THE GEORGIA COASTAL WATERS THROUGH TUESDAY. WAVES OF HEAVY SHOWERS
AND EMBEDDED THUNDERSTORMS WILL PERIODICALLY OVERSPREAD THE WATERS
THROUGH TUESDAY...WHILE SOUTH TO SOUTHWEST WIND SPEEDS WILL
GENERALLY REMAIN NEAR OR BELOW 15 MPH OUTSIDE OF HEAVIER SHOWERS
AND THUNDERSTORMS THROUGH THE PERIOD AND SEAS REMAIN IN THE 2 TO
3 FOOT RANGE. ATLANTIC HIGH PRESSURE WILL THEN BUILD OVER THE
COASTAL WATERS FOR THE MID AND LATE WEEK TIME FRAME...WITH
DECREASING RAIN CHANCES AND LIGHT SOUTH TO SOUTHWEST WIND
SPEEDS...WITH THE DAILY AFTERNOON SEA BREEZE DEVELOPING IN THE
NEAR SHORE WATERS.
RIP CURRENTS: LOW RISK CONTINUES...WITH A SMALL SOUTHEASTERLY
OCEAN SWELL OF LESS THAN 2 FEET AFFECTING THE BEACHES DURING THE
NEXT FEW DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 88 72 89 72 / 80 70 70 60
SSI 85 75 85 74 / 80 70 70 60
JAX 87 73 88 73 / 80 60 70 60
SGJ 86 75 87 73 / 80 60 60 60
GNV 87 72 88 71 / 70 50 60 50
OCF 88 72 88 72 / 70 40 60 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
NELSON/ENYEDI
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
524 AM EDT SUN SEP 7 2014
...FLOOD THREAT PERSISTS IN THE SUWANNEE VALLEY THROUGH EARLY THIS
WEEK...
.CURRENTLY...
EARLY MORNING SURFACE ANALYSIS DEPICTS A LOW PRESSURE TROUGH
EXTENDING FROM COASTAL SOUTHEAST GEORGIA SOUTHWESTWARD TO THE
NORTHEAST GULF OF MEXICO. A COLD FRONT IS EXITING THE MID-ATLANTIC
COAST AND THE TENNESSEE VALLEY REGION...AND IS ENTERING THE
SOUTHEASTERN STATES. MEANWHILE...THE AXIS OF ATLANTIC RIDGING
EXTENDS ACROSS THE FLORIDA PENINSULA. ALOFT...WEAK CYCLONIC FLOW
PREVAILS OVER OUR REGION...IN BETWEEN RIDGES OVER THE WESTERN AND
CENTRAL ATLANTIC AND THE DESERT SOUTHWEST. SLOW MOVING NOCTURNAL
CONVECTION HAS ONCE AGAIN FIRED ALONG THE SURFACE TROUGH OVER THE
SUWANNEE VALLEY...WITH THE SOUTHERN HALF OF COLUMBIA COUNTY ONCE
AGAIN BEING THE TARGET AREA OF THE HEAVIEST RAINS. DOPPLER RADAR
ESTIMATES DURING THE PAST 24 HOURS DEPICT A SWATH OF 5 TO 8 INCH
RANGE IN SOUTHERN COLUMBIA AND FAR EASTERN SUWANEE COUNTIES...WITH
A BULLS-EYE OF 9 TO 14 INCH TOTALS JUST SOUTH OF LAKE CITY. WITH
HEAVY DOWNPOURS...SOME CONTAINING RAINFALL RATES IN EXCESS OF 2
INCHES PER HOUR...FALLING OVER THESE SATURATED GROUND
CONDITIONS...A FLASH FLOOD WARNING HAS BEEN ISSUED FOR CENTRAL
COLUMBIA COUNTY THROUGH 7 AM. ELSEWHERE...SCATTERED TO NUMEROUS
SHOWERS ARE ALSO OVERSPREADING THE REMAINDER OF NORTHEAST AND
NORTH CENTRAL FLORIDA...AS WELL AS COASTAL SOUTHEAST GEORGIA.
BENEATH EXTENSIVE MULTI-LAYERED CLOUDINESS...TEMPERATURES AND
DEWPOINTS AT 09Z WERE GENERALLY IN THE MID 70S.
.NEAR TERM (TODAY AND TONIGHT)...
SHORT TERM HI-RESOLUTION MODELS SUCH AS THE 03Z HRRR HAVE
INITIALIZED THE NOCTURNAL CONVECTIVE BURST OVER THE SUWANNEE
VALLEY...AND THIS MODEL SUGGESTS THAT ACTIVITY WILL TRANSITION
SOUTH AND EASTWARD INTO NORTH CENTRAL AND NORTHEAST FLORIDA DURING
THE MORNING HOURS. A FRONTAL BOUNDARY WILL APPROACH SOUTHEAST GA
LATER TODAY...WHICH SHOULD LIFT LOW PRESSURE SLOWLY NORTHEASTWARD
INTO COASTAL SOUTHEAST GA. SIMILAR TO YESTERDAY...MORNING
CONVECTION OVER NORTHEAST FL AND COASTAL SOUTHEAST GA WILL LIKELY
FADE BY THE LATE MORNING HOURS. HOWEVER...WITH FORCING ASSOCIATED
WITH THE FRONT ARRIVING INTO OUR REGION DURING PEAK
HEATING...ANOTHER ROUND OF LOCALLY HEAVY DOWNPOURS AND EMBEDDED
THUNDERSTORMS APPEARS LIKELY DURING THE LATE AFTERNOON AND EARLY
EVENING HOURS OVER MUCH OF OUR REGION. CATEGORICAL POPS WERE THUS
INSERTED FOR MUCH OF SOUTHEAST GA...WHERE THE GREATEST MOISTURE
CONVERGENCE WILL BE LOCATED LATER TODAY. SINCE WE EXPECT A BREAK
IN THE HEAVY DOWNPOURS OVER THE SUWANNEE VALLEY LATER THIS
MORNING...WE WILL HOLD OFF ON ISSUING ANY LARGE SCALE FLOOD
WATCHES AT THIS TIME. HOWEVER...LOCALIZED FLOODING WILL BE A
GROWING CONCERN REGION-WIDE AS TROPICAL MOISTURE REMAINS IN PLACE
DURING AT THE LEAST THE NEXT FEW DAYS...AND WEAK STEERING FLOW
ALOFT RESULTS IN CONTINUED SLOW MOVEMENT OF CONVECTION. SOME
BREAKS IN THE CLOUDS OVER INTERIOR SOUTHEAST GEORGIA THIS MORNING
WILL ALLOW TEMPERATURES TO RISE TO NEAR 90 BEFORE CLOUDS AND
RAINFALL DEVELOP THIS AFTERNOON. ELSEWHERE...ABUNDANT CLOUDS WILL
KEEP HIGHS IN THE MID/UPPER 80S.
WIDESPREAD RAINS MAY BE SLOW TO DEPART COASTAL SOUTHEAST GA
TONIGHT...AS LOW PRESSURE BEGINS TO LIFT SLOWLY NORTHEASTWARD
AHEAD OF THE STALLING FRONTAL BOUNDARY. OTHERWISE...SHOWERS SHOULD
DECREASE IN COVERAGE OVER NORTHEAST AND NORTH CENTRAL FL DURING
THE EARLY EVENING HOURS. A BAND OF CONVECTION MAY DEVELOP OVER THE
NORTHEAST GULF OF MEXICO DURING THE PREDAWN HOURS ON MONDAY...AND
THIS ACTIVITY COULD IMPACT PORTIONS OF NORTH CENTRAL FL BEFORE
SUNRISE. THE TROPICAL AIR MASS WILL KEEP LOWS IN THE 70S REGION-
WIDE.
.SHORT TERM (MONDAY THROUGH WEDNESDAY)...
ABUNDANT TROPICAL MOISTURE WILL PERSIST OVER OUR REGION ON MONDAY
AS LOW PRESSURE LIFTS NORTHEASTWARD ALONG THE GA/SC COASTS.
MEANWHILE...A STALLED FRONTAL BOUNDARY WILL RESIDE JUST WEST OF
OUR REGION...WITH MODEL SOUNDINGS DEPICTING DEEP W/SW FLOW
PERSISTING ALONG A TRAILING TROUGH FROM THE LOW PRESSURE CENTER.
SIGNIFICANT MOISTURE CONVERGENCE WILL REMAIN IN PLACE ALONG THIS
TROUGH AND AHEAD OF THE FRONT...WITH ABUNDANT CLOUDS AND ANOTHER
ROUND OF SCATTERED TO NUMEROUS THUNDERSTORMS EXPECTED TO IMPACT
MUCH OF OUR REGION. ADDITIONAL WIDESPREAD RAINS OF 1 TO 2 INCHES
WITH LOCALLY HIGHER TOTALS WILL KEEP THE THREAT OF FLOODING IN
PLACE...PARTICULARLY IN URBAN AND COASTAL LOCATIONS DURING THE
AFTERNOON AND EVENING HOURS. WIDESPREAD CLOUDS AND A RELATIVELY
EARLY START TO CONVECTION WILL KEEP HIGHS IN THE UPPER 80S.
RAINFALL SHOULD DIMINISH OVER MOST OF THE REGION DURING THE EARLY
EVENING HOURS ON MON...WITH MUGGY LOWS IN THE 70S EXPECTED.
TUE...A WAKE TROUGH WILL LINGER OVER THE FORECAST AREA AS THE
PARENT LOW TRACKS NE ALONG THE ATLANTIC SEABOARD. THIS BOUNDARY
COMBINED WITH A LINGERING PLUME OF HIGHER MOISTURE WILL SLOWLY
SHIFT SOUTHWARD OVER NE FL TUE AFTN...AND PROVIDE A FOCUS ANOTHER
ROUND OF NUMEROUS SHOWERS AND TSTORMS. DRIER AND MORE STABLE AIR
WILL GRADUALLY INFILTRATE OVER SE GA THROUGH TUE AND ADVERTISED
LOWER RAIN CHANCES IN THE 40-50% RANGE...WITH 60% OVER NE FL
DURING THE AFTN/EVENING. PRECIP WILL SHIFT TO THE ESE INTO THE
EVENING HOURS WILL DECREASING IN COVERAGE AND INTENSITY WITH THE
LOSS OF DAYTIME INSTABILITY. HIGH TEMPS TUE WILL RANGE IN THE
MID/UPPER 80S INLAND TO LOW/MID 80S COAST WITH OVERNIGHT LOWS TUE
NIGHT FALLING INTO THE UPPER 60S TO LOW 70S INLAND WITH DRIER AIR
IN PLACE AND CLEARING SKIES. PATCHY LATE NIGHT FOG POSSIBLE.
WED...LOWER RAIN CHANCES WITH STACKED HIGH PRESSURE OVER THE
AREA...HOWEVER LINGERING MOISTURE PLUME WILL CONTINUE TO SUPPORT A
CHANCE OF MAINLY AFTN/EARLY EVENING SHOWERS AND ISOLATED TSTORMS
WITH THE HIGHEST CHANCES OVER INLAND NE FL. RAIN CHANCES RANGE
FROM 30% OVER INLAND SE GA TO 35% OVER INLAND NE FL. WARM UPPER
LEVEL TEMPS AND SUBSIDENCE WILL KEEP THUNDERSTORMS TAME AND SPARSE
IN COVERAGE...SO ONLY INDICATED ISOLATED TSTORMS IN THE FORECAST.
TEMPS WILL WARM INTO THE LOW 90S INLAND TO MID 80S COAST WITH LOWS
COOLING INTO THE LOW 70S INLAND/MID 70S COAST WED NIGHT.
.LONG TERM (THURSDAY THROUGH SUNDAY)...
THU & FRI MEAN LAYER 1000-500 MB RIDGE AXIS WILL EXTEND ACROSS NE
FL AND SE GA WITH PWATS FALLING INTO THE 1.5-1.9 RANGE WITH THE
HIGHER VALUES OVER SE GA. ADVERTISED NEAR TO SLIGHTLY BELOW RAIN
CHANCES BOTH DAYS IN THE 30-40% RANGE WITH A DIURNAL PATTERN AND
LIGHT SOUTH STEERING FLOW WHICH WILL ENABLE BOTH SEA BREEZES TO
PUSH INLAND AND FOCUS A MERGER BETWEEN THE ST JOHNS RIVER BASIN
AND INTERSTATE 75. HIGHS WILL BE NEAR TO ABOVE NORMAL GIVEN
STACKED SUBSIDENCE WITH UPPER 80S TO LOW 90S INLAND TO MID 80S
COAST...WITH MILD LOWS RANGING IN THE 70S.
SAT & SUN RAIN CHANCES INCREASE AS A FRONTAL ZONE STALLS OVER GA
AND A TROPICAL WAVE ROTATES NORTHWARD FROM THE BAHAMAS. PWATS
INCREASE TO OVER 2 INCHES BY SUNDAY. THUS INCREASED RAIN CHANCES
INTO THE 40-50% RANGE...BUT IF MODEL PERSISTENCE
CONTINUES...LIKELY POPS MAY BE NEEDED NEXT WEEKEND (60-70%). TEMPS
WILL BEGIN TO FALL BACK TO NEAR TO SLIGHTLY BELOW CLIMO FOR HIGHS
GIVEN INCREASED CLOUD COVER AND LOWER THICKNESSES WITH HIGHS IN
THE MID/UPPER 80S AND MUGGY LOWS CONTINUING IN THE 70S.
&&
.AVIATION...
PERIODS OF SUB-VFR CONDITIONS WILL CONTINUE THROUGHOUT THE
DAY...WITH TEMPO GROUPS USED FOR IFR VISIBILITIES AND MVFR CIGS
THROUGH AROUND 12Z. ANOTHER ROUND OF POTENTIAL IFR CONDITIONS IS
POSSIBLE AT THE TERMINALS THIS AFTERNOON AS WEAK LOW PRESSURE OVER
OUR REGION DEVELOPS NUMEROUS SLOW MOVING SHOWERS AND THUNDERSTORMS
AFTER 15Z. OUTSIDE OF HEAVIER SHOWERS AND
THUNDERSTORMS...SOUTHWEST WINDS WILL INCREASE TO NEAR 10 KNOTS
THIS AFTERNOON AT THE REGIONAL TERMINALS.
&&
.MARINE...
WEAK LOW PRESSURE WILL BE SLOW TO MOVE AWAY FROM OUR REGION
THROUGH MONDAY...WHILE A FRONTAL BOUNDARY STALLS JUST NORTHWEST OF
THE GEORGIA COASTAL WATERS THROUGH TUESDAY. WAVES OF HEAVY SHOWERS
AND EMBEDDED THUNDERSTORMS WILL PERIODICALLY OVERSPREAD THE WATERS
THROUGH TUESDAY...WHILE SOUTH TO SOUTHWEST WIND SPEEDS WILL
GENERALLY REMAIN NEAR OR BELOW 15 MPH OUTSIDE OF HEAVIER SHOWERS
AND THUNDERSTORMS THROUGH THE PERIOD AND SEAS REMAIN IN THE 2 TO
3 FOOT RANGE. ATLANTIC HIGH PRESSURE WILL THEN BUILD OVER THE
COASTAL WATERS FOR THE MID AND LATE WEEK TIME FRAME...WITH
DECREASING RAIN CHANCES AND LIGHT SOUTH TO SOUTHWEST WIND
SPEEDS...WITH THE DAILY AFTERNOON SEA BREEZE DEVELOPING IN THE
NEAR SHORE WATERS.
RIP CURRENTS: LOW RISK CONTINUES...WITH A SMALL SOUTHEASTERLY
OCEAN SWELL OF LESS THAN 2 FEET AFFECTING THE BEACHES DURING THE
NEXT FEW DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 88 72 89 72 / 80 70 70 60
SSI 85 75 85 74 / 80 70 70 60
JAX 87 73 88 73 / 80 60 70 60
SGJ 86 75 87 73 / 80 60 60 60
GNV 87 72 88 71 / 70 50 60 50
OCF 88 72 88 72 / 70 40 60 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
NELSON/ENYEDI
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
209 AM EDT Sun Sep 7 2014
.Near Term [Through Today]...
The overnight analysis shows a rather diffuse synoptic pattern in
place across the area with weak flow aloft. Deep layer moisture is
plentiful with a large area of precipitable water values over 2
inches. There still appears to a remnant weak and broad mid to upper
level circulation just east of the area as seen on VAX radar.
Convection has been expanding with this feature overnight with very
heavy rain rates noted just south of Lake City. This is similar to
what happened last night when a large area of moderate to heavy rain
eventually developed and affected portions of the southeast big
bend. In fact, the recent HRRR runs are showing a similar evolution
for the remainder of tonight and into the first half of today, and
with radar trends so far supporting this general thinking, the
official forecast bumped up PoPs to categorical across the southeast
big bend and added a mention of heavy rainfall for the first half of
today. With the heaviest rainfall currently expected to remain just
east of the forecast area, confidence is not high enough to issue a
watch at this time, although trends will have to be closely
monitored in that region. The forecast high temperatures were also
kept on the lower side of the guidance in the mid 80s given the
expected cloud cover and rain. It is possible that they could end up
even lower than that given Cross City only made it to 79 yesterday,
but did not want to go too low as it will only take a couple of
hours of sunshine to make it well up into the 80s.
Elsewhere, PoPs are also fairly high today, generally in the likely
range, with a high coverage of afternoon showers and thunderstorms
expected to develop given the abundant deep layer moisture in place.
Outside of the southeast big bend, more sunshine is expected though
initially with high temperatures forecast to reach the lower 90s.
.Short Term [Tonight Through Tuesday]...
The GFS and ECMWF are in fairly good agreement, as they begin to
slowly shift the weak mid layer trough (currently centered over
north FL) eastward on Tuesday. At the surface, the weak,
quasi-stationary frontal zone across south GA & AL will gradually
dissipate. As has been the case the past several model runs, the
pressure/height pattern is forecast to be too weak for any sustained
Q-G forcing, so much of the forcing for deep moist convection will
be due to diurnal mesoscale forcing from sea breeze fronts and the
like. With ample deep layer moisture and moderate instability on
Monday, PoPs will continue to be above climo- especially in the
afternoon & evening hours (50-60%). Deep layer moisture will begin
to diminish on Tuesday, especially over our western zones, where the
PoP will only be 20%. Elsewhere, where the moisture will linger
longer, PoPs will be in the 40-50% range. Highs will be in the upper
80s to lower 90s, lows in the 70s.
.Long Term [Tuesday Night Through Sunday]...
We expect rain chances to remain at or above climo throughout most
of the period, as the position of the Bermuda High at the Sfc will
still allow for plenty of deep layer tropical moisture to be
pumped into the region with a southerly component to the winds
below 500 mb (until next Fri. and Sat. when the next active trof
approaches), keeping PWATs in the 1.85" to 2.15" range. However,
the ridging should at least allow the convection to return towards
more of a diurnal cycle with the sea breeze circulation, and while
above climo, Pops should generally remain between 40% to 60% or
slightly below on a couple of days. Temps should also average a
bit above climo through the next 7 days, with highs generally in
the lower 90s with lows in the lower to middle 70s.
&&
.Aviation...
[Through 06Z Monday] There is a chance of some MVFR to IFR
conditions across most of the TAF sites for a few hours around dawn
with plentiful low level moisture in place and a fairly high
coverage of rainfall yesterday. VFR conditions are expected to
return by mid-morning with another afternoon of scattered to
numerous showers and thunderstorms across the area.
&&
.Marine...
The pressure gradient will remain weak through at least mid week,
resulting in a continuation of low winds and seas. However, there
may be a slight increase in winds and chop near the coast each
afternoon from strong heating of the land.
&&
.Fire Weather...
Over the next few days, relative humidity values will remain well
above critical thresholds with a fairly high coverage of afternoon
showers and thunderstorms. Red flag conditions are not expected.
&&
.Hydrology...
1 to 2 inches of rain (with locally higher amounts) fell across a
large portion of north FL on Saturday. Elsewhere the rain wasn`t as
concentrated, though there were isolated heavy amounts. Some rivers
have risen in recent days, but are still well below flood stage.
Although slow storm motion and high moisture content makes flooding
a possibility today, we still don`t see a concentrated area of
forcing where heavy rain would become focused for a long period of
time. Once again, the most vulnerable areas to flash flooding will
be urban areas and locations that had very heavy rain on Saturday.
River flooding appears unlikely due to the isolated nature of the
heavy rainfall threat.
&&
.Preliminary Point Temps/PoPs...
Tallahassee 91 73 90 72 91 / 60 30 50 20 40
Panama City 89 76 88 76 90 / 60 40 50 20 30
Dothan 92 71 91 71 92 / 70 40 50 20 20
Albany 92 72 91 72 92 / 70 50 60 30 30
Valdosta 90 71 90 71 91 / 70 40 60 30 50
Cross City 87 72 88 72 90 / 80 30 60 30 50
Apalachicola 89 76 87 75 89 / 50 40 40 20 40
&&
.TAE Watches/Warnings/Advisories...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...DVD
SHORT TERM...FOURNIER
LONG TERM...GOULD
AVIATION...DVD
MARINE...FOURNIER
FIRE WEATHER...DVD
HYDROLOGY...FOURNIER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
409 AM EDT SUN SEP 7 2014
.SYNOPSIS...
COOL AND DRY HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT THIS
AFTERNOON INTO MONDAY. THIS HIGH WILL LINGER INTO THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
MUCH COOLER AND DRIER THIS TERM.
06Z SURFACE ANALYSIS SHOWED A COLD FRONT HANGING OFF THE COAST
W/AN AREA OF SHOWERS MOVING UP ALONG THE COAST. THESE SHOWERS WERE
IN RESPONSE TO A WEAK SFC LOW THAT DEVELOPED ON THE FRONT. LATEST
SREF WAS HANDLING THE SHOWERS QUITE WELL W/THE SETUP. DECIDED TO
CARRY 60% POPS RIGHT ALONG THE COAST FOR EARLY THIS MORNING AND
THEN DROP THEM OFF AS THE LOW PULLS NE AND THE FRONT PULLS FURTHER
S. IR SATELLITE IMAGERY SHOWED CLOUDS ACROSS THE CWA W/CLEARING
TAKING PLACE ACROSS THE NORTHERN TIER. THE CLOUDS WILL PULL OUT OF
THE AREA BY LATE MORNING AS DRIER AIR CONTINUES TO POUR IN. A
SECOND FRONTAL BOUNDARY IS SHOWN BY THE NAM AND HRRR 3KM TO DROP S
ACROSS THE REGION THIS AFTERNOON. THE MODEL SOUNDINGS SUPPORT
MOISTURE IN THE 900-800MB LAYER ACROSS THE NORTHERN 1/2 OF THE CWA
WHILE DOWNEAST AND THE COAST WILL SEE SOME SCATTERED CLOUDINESS.
NW WINDS WILL PICK UP BEHIND THIS FRONT W/TEMPERATURES THIS
AFTERNOON ABOUT 10-15 DEGREES COLDER THAN THEY HAVE BEEN THE LAST
SEVERAL DAYS. WE ARE TALKING UPPER 60S TO AROUND 70.
HIGH PRES IS FORECAST TO SLIDE ACROSS THE REGION TONIGHT
W/CLEARING SKIES AND MUCH DRIER AIR. NW WINDS WILL DROP OFF
TONIGHT W/DEWPOINTS DROPPING INTO THE 30S BY EARLY MONDAY MORNING.
DECIDED TO CARRY PATCHY FOG W/THE COOLING AND WET GROUND FROM
SATURDAY`S RAIN. TEMPERATURES BY SUNRISE WILL HIT THE MID AND
UPPER 30S W/LOCATIONS SUCH AS THE ALLAGASH AND ST. JOHN VALLEY
SEEING LOWER 30S. THIS RAISES CONCERN FOR FROST BY EARLY MONDAY
MORNING MAINLY ACROSS THE NORTH AND WEST. COLLABORATED W/GYX AND
BTV ON THIS AND THINKING IS THAT THE FOG COULD OFFSET THE EXTENT
OF THE FROST W/A HEAVY DEW DEVELOPING. PLUS, WINDS COULD ACTUALLY
STAY UP A WHILE LONGER BEFORE DECOUPLING WHICH IN TURN LIMIT THE
DURATION OF THE FROST. THEREFORE, THE DECISION WAS NOT TO ISSUE A
FROST ADVISORY W/THIS PACKAGE BUT KEEP THE MENTION OF FROST IN
THE FORECAST. DAYCREW CAN ASSESS THIS FURTHER TODAY.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE AREA THROUGH THE
SHORT TERM PERIOD. A LOW PRESSURE SYSTEM WILL MOVE NORTH ALONG THE
ATLANTIC COAST...AT THIS TIME APPEARS WILL REMAIN SOUTH OF THE
GULF OF MAINE.
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 /WEDNESDAY THROUGH SATURDAY/...
A HIGH PRESSURE RIDGE WILL BE IN PLACE OVER THE AREA AT THE START
OF THE LONG TERM. A LOW TRACKING ACROSS THE GREAT LAKES WILL BRING
ITS ASSOCIATED FRONT INTO WRN MAINE THURS MRNG. THE GUIDANCE MOVES
THE FRONT INTO NEW BRUNSWICK FRI MRNG....UNSETTLED WEATHER WILL
CONTINUE AS THE UPPER LEVEL LOW ELONGATES ALONG THE US AND
CANADIAN BOARDER EXTENDING FRONT THE CENTRAL GREAT LAKES TO
ATLANTIC CANADA. THE UPPER LOW WILL REMAIN IN THE AREA THROUGH THE
END OF THE PERIOD. TROUGHS OF LOWER PRESSURE WILL ROTATE AROUND
THE LOW BRINGING PERIODS OF UNSETTLED WEATHER INTO NRN AND CENTRAL
MAINE THROUGH THE END OF THE PERIOD.
LOADED THE SUPERBLEND FOR THE EXTENDED PERIOD OF THE FORECAST.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: VFR W/TEMPO MVFR OR PERHAPS IFR BY EARLY MONDAY MORNING
FOR FOG DUE TO WET GROUND.
SHORT TERM: HIGH PRESSURE WILL DOMINATE THE WEATHER THROUGH THE
PERIOD. VFR CONDITIONS ALL SITE. LIGHT WINDS...COOLER TEMPS WILL
LIKELY ALLOW MORNING FOG PARTICULARLY AROUND WATER BODIES REDUCING
VISIBILITIES DURING THE EARLY MORNING HOURS.
&&
.MARINE...
NEAR TERM: WINDS HAVE DROPPED TO 10 KTS BUT SEAS STILL RUNNING
AROUND 5 FT. THINKING IS THAT SEAS WILL DROP BACK TODAY AS NW TAKE
HOLD AND HIGH PRES BUILDS E. WINDS WILL REMAIN 10 KT OR LESS.
SHORT TERM: WINDS AND SEAS BELOW SCA CRITERIA THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...NORTON
LONG TERM...NORTON
AVIATION...HEWITT/NORTON
MARINE...HEWITT/NORTON
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
506 AM EDT SUN SEP 7 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE AREA INTO THIS AFTERNOON. THE
FRONT WILL STALL ALONG THE SOUTHEAST AND MID ATLANTIC COASTS
LATER THIS AFTERNOON THROUGH TUESDAY NIGHT...WITH AN AREA OF LOW
PRESSURE MOVING NORTHEAST ALONG THE BOUNDARY MONDAY AFTERNOON
THROUGH TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A COLD FRONT WILL DROP ACRS THE REGION THIS MORNG INTO THIS
AFTN...THEN STALL ALONG THE SE AND MID ATLC CSTS LATER THIS AFTN
THRU TUE NGT...AS HI PRES BLDS FM THE OH VLY/LWR GRT LKS ENE INTO
THE CANADIAN MARITIMES. DRIER AIR WILL TRY TO NUDGE INTO NNW
PORTIONS OF THE AREA THIS AFTN INTO THIS EVENG...RESULTING IN THE
HIGHEST POPS (50-70%) SHIFTING INTO SRN/SE CNTIES. GENERALLY MSTLY
CLDY WITH POPS 15-25%. HI TEMPS WILL RANGE FM THE UPR 70S N TO
THE LWR 80S SE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
GOING WITH A BLEND OF THE LATEST GFS/ECMWF MODELS FOR TNGT THRU
TUE NGT...RESULTING IN AN UNSETTLED RATHER WET PATTERN FOR THE
REGION. LO PRES DEVELOPING ALNG THE SE CST TNGT INTO MON...WILL
LIFT NE ALNG THE STALLED FRNTL BOUNDARY AND OFF THE VA/NC CST MON
AFTN THRU TUE NGT. THE COMBINATION OF INCREASING LO LVL MOISTURE
FM THE ATLC AND STRNG LIFT (ALNG/JUST N OF THE BOUNDARY AND
ASSOCIATED WITH THE LO)...WILL PRODUCE NUMEROUS SHOWERS OVR THE
AREA...ESPLY LATER TNGT INTO TUE AFTN. HIGHEST POPS/CHC FOR
HEAVIEST RAINFALL WILL BE OVR ERN/SERN CNTIES DURING THIS TIME.
POPS WILL DIMINISH FM W TO E TUE AFTN THRU TUE NGT...AS THE LO
MOVES FARTHER OUT TO SEA. ISLTD THUNDER POSSIBLE ESE AREAS.
LO TEMPS TNGT RANGING THRU THE 60S TO NEAR 70. HI TEMPS ON MON AND
TUE IN THE MID 70S TO ARND 80.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MEDIUM RANGE GUIDANCE IN FAIRLY GOOD AGREEMENT THROUGH THE
PERIOD. THE MAIN FEATURE WILL BE A COLD FRONT SET TO CROSS THE
LOCAL AREA LATE IN THE WEEK...BRINGING COOLER/DRIER CONDITIONS TO
THE REGION BY NEXT WEEKEND.
UPPER FLOW WILL BE CHARACTERIZED BY AN AMPLIFYING TROUGH OVER THE
CNTRL CONUS...DOWNSTREAM OF AN ANOMALOUS RIDGE OVER THE WRN
PACIFIC AND GULF OF ALASKA. OVER THE LOCAL AREA...A LEADING
SHORTWAVE WILL FLATTEN THE UPPER FLOW BRIEFLY WEDS BEFORE SWLY
FLOW INCREASES IN ADVANCE OF THE APPROACHING UPPER TROUGH THURS-
FRI. AN ASSOCIATED COLD FRONT AND PARENT LOW WILL REACH THE GREAT
LAKES/OH VALLEY LATE WEDS INTO WEDS NIGHT. MEANWHILE...WEDGE OVER
THE LOCAL AREA BREAKS DOWN IN ADVANCE OF THE FRONT WEDS. MID-LEVEL
HIGH PRESSURE OVER THE SE STATES WILL RIDGE NEWD INTO THE MID-
ATLANTIC AS SFC HIGH BREAKS DOWN. SUBSIDENCE VISIBLE IN MODEL
SOUNDINGS COMBINED WITH LITTLE INSTABILITY AND THETA-E ADVECTION
WILL LIKELY INHIBIT PRECIP WEDS. WINDS VEER TO THE SOUTH WEDS
NIGHT AS SWLY FLOW ALOFT INCREASES. PRE-FRONTAL TROUGH FORECAST TO
DEVELOP OVER THE LOCAL AREA THURS...WHICH COMBINED WITH THETA-E
ADVECTION/INSTABILITY MAY PROVIDE THE FOCUS FOR AFTERNOON SHOWERS
AND THUNDERSTORMS. HOWEVER...LACK OF APPRECIABLE FORCING OUTSIDE
OF SMALL AMPLITUDE WAVES IN SWLY FLOW WILL LIKELY RESULT IN ONLY
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS. BEST COVERAGE
ANTICIPATED OVER THE PIEDMONT INTO CNTRL VA AND ALONG THE COAST TO
ACCOUNT FOR SEABREEZE BOUNDARIES. MODELS IN GOOD AGREEMENT WITH
DROPPING THE COLD FRONT INTO THE LOCAL AREA LATE THURS NIGHT INTO
FRI. THE UPPER WAVE DE-AMPLIFIES...WITH THE BEST DYNAMICS REMAINING
NORTH OF THE LOCAL AREA. DESPITE LACK OF DYNAMICS...WILL INCREASE
POPS TO CHANCE AS A WARM/MOIST AND MARGINALLY UNSTABLE AIR MASS IS
ANTICIPATED. OF COURSE...TIMING OF THE FRONT WILL IMPACT WHERE THE
BEST COVERAGE WILL BE ON FRIDAY AND HOW WARM TEMPS GET. EXPECT THE
FRONT TO CLEAR THE LOCAL AREA FRI NIGHT AS COOL CANADIAN HIGH
PRESSURE BUILDS IN FROM THE WEST. BEST CAA ARRIVES FRI NIGHT-SAT
AS HIGH PRESSURE REMAINS OVER THE OH VALLEY. THE RESULT WILL BE
PARTLY CLOUDY SKIES SAT WITH HIGHS IN THE UPPER 70S. WILL HOLD
ONTO SLIGHT CHANCE-CHANCE POPS ACROSS THE SE TO ACCOUNT FOR SLOWER
ECMWF AND PROXIMITY TO FRONT/MOISTURE.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
AS OF 09Z...A COLD FRONT HAD DROPPED SOUTH OF RIC-SBY...AND WILL
DROP ACROSS REMAINDER OF TERMINALS THROUGH MID-MORNING.
SOME SCT SHRAS/TSTMS WERE STILL NOTED ALONG AND JUST SOUTH OF SBY AT
09Z...AND COULD SEE A BRIEF PERIOD OF SHRAS AT RIC JUST BEFORE
SUNRISE. THE FRONT IS EXPECTED TO MOVE THROUGH PHF/ORF AROUND 09-10Z
AND ECG BY 12Z. A BRIEF PERIOD OF LIGHT RAIN IS POSSIBLE FOLLOWING
THE FRONTAL PASSAGE...BUT HV GONE WITH VCSH AT SE TERMINALS FOR NOW.
EXPECT RETURN TO VFR BY MIDDAY AT RIC BUT ELSEWHERE AT SBY AND
FARTHER TO THE SE, KEPT LOW CLOUDS (MVFR CIGS) IN PLACE FOR MUCH OF
THE DAY. NE WINDS IN THE WAKE OF THE FRONT WILL INCREASE TO 10 TO 15
KNOTS AT ORF AND ECG AS THE PRESSURE GRADIENT TIGHTENS IN THAT AREA.
OUTLOOK...UNSETTLED CONDITIONS CONTINUE LATE TNGT THROUGH TUESDAY
WITH PERIODS OF MVFR AND SOME BRIEF PERIODS OF IFR PSBL...ESPECIALLY
AT ORF AND ECG MONDAY NIGHT AND EARLY TUESDAY. DRIER WEATHER IS
FORECAST LATE TUESDAY THROUGH FRIDAY.
&&
.MARINE...
LATEST SFC ANALYSIS SFC COLD FRONT MOVING SOUTH ACROSS THE WATERS
THIS MORNING, WITH SOME SCT SHRAS ACROSS NORTHERN WATERS ALONG
PRE-FRONTAL TROUGH. FLOW IS E-NE ACROSS NORTHERN WATERS, WITH SW
FLOW FARTHER SOUTH ALONG CENTRAL/SOUTHERN COASTAL WATERS AND THE
LOWER CHES BAY. FRONT WILL DROP SOUTH ACROSS THE WATERS OVER THE
NEXT FEW HOURS WITH A BRIEF SURGE EXPECTED LATER THIS MORNING AS THE
BETTER CAA ARRIVES. LOOKING AT OBS IN THE UPPER CHES BAY, NOTING
GUSTS TO 18-22 KT OVER UPPER BAY, GENERALLY IN LINE WITH HRRR
DEPICTION. HRRR AND DOWNSCALE NAM DEPICTING A SHORT LIVED N-NE SURGE
WITH NE WINDS GUSTING TO MARGINAL/LOW END SCA IN THE BAY.
ACCORDINGLY, HV HOISTED A RELATIVELY SHORT DURATION SCA THROUGH
NOON.
FRONT WILL BECOME STALLED ALONG THE COAST LATE TONIGHT AND MONDAY
AS HIGH PRESSURE BUILDS OVER NEW ENGLAND. E-NELY FLOW CONTINUES
THROUGH THE PERIOD WITH HIGH PRESSURE REMAINING RIDGED OVER THE
WATERS THRU WEDNESDAY. MEANWHILE...LOW PRESSURE WILL DEVELOP ALONG
THE FRONT AND LIFT ALONG THE SE COAST AND OFF THE MID-ATLANTIC COAST
MON-WED. THIS WILL SERVE TO STRENGTHEN THE PRESSURE GRADIENT OVER
THE NRN WATERS...RESULTING IN NELY WINDS OF 20-25 KT OVER THE NRN
COASTAL WATERS DEVELOPING LATE TONIGHT INTO MON. SEAS WILL
RESPOND...BUILDING TO 4-6 FT NORTH OF CAPE CHARLES LIGHT. HV GONE
AHEAD WITH AN SCA OVER ATLANTIC COASTAL WATERS NORTH OF PARRAMORE
ISLAND FROM 6A MON-6A TUES. WINDS/SEAS REMAIN ELEVATED MON/MON NGT
BEFORE THE PRESSURE GRADIENT RELAXES. WEDGE BEGINS TO BREAK DOWN
WEDS AS A COLD FRONT APPROACHES FROM THE WEST. FLOW BECOMES SLY WED
NIGHT INTO THURS AND SWLY THURS AND FRI IN ADVANCE OF THE NEXT COLD
FRONT, WHICH IS FORECAST TO CROSS THE WATERS THURS NIGHT INTO FRI.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
ANZ650-652.
SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR ANZ630>632.
&&
$$
SYNOPSIS...TMG
NEAR TERM...TMG
SHORT TERM...ALB/TMG
LONG TERM...SAM
AVIATION...MAM
MARINE...MAM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
440 AM EDT SUN SEP 7 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM EDT SUN SEP 7 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR LKS BTWN AN UPR RDG OVER WRN NAMERICA AND A TROF IN THE E. A
SHRTWV EMBEDDED IN THIS WNW FLOW IS LOCATED NEAR JAMES BAY EARLY
THIS MRNG. A RIBBON OF MSTR/CLD COVER/SOME SHOWERS IS NOTED ALONG
ITS ATTENDANT COLD FNT STRECHING SWWD TOWARD NRN LK SUP AND A WEAK
LO PRES CENTER RUNNING EWD ALONG THE MN/ONTARIO BORDER. THE THICKER
CLDS AND SHOWERS JUST N OF LK SUP APPEAR TO FORCED BY AREA OF H85-5
QVECTOR CNVGC DEPICTED BY THE SHORT TERM MODELS. UPR MI IS DOMINATED
BY A LLVL W FLOW BTWN THE COLD FNT/SFC LO AND HI PRES MOVING INTO
THE MID MS RIVER VALLEY. THE UPSTREAM 00Z INL RAOB IS FAIRLY DRY
WITH 00Z H85/H7 DEWPT DEPRESSIONS RUNNING AT 7C/8C.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON HOW FAR S THE
AREA OF CLDS/SHOWERS JUST N OF LK SUP WL MOVE AND TEMPS FOR THIS
AFTN/TNGT.
TODAY...AS THE SHRTWV NEAR JAMES BAY MOVES ESEWD THRU QUEBEC
TODAY...ITS ATTENDANT COLD FNT IS PROGGED TO SHIFT S THRU NRN LK SUP
BEFORE STALLING NEAR THE KEWEENAW. SINCE THE AREA OF QVECTOR CNVGC
FORCING THE THICKER CLDS/SHOWERS NOW IN ONTARIO IS FCST TO SHIFT
ESEWD OVER NRN LK SUP AND N OF THE LAND CWA WITH THE DRY H85-7 W
FLOW DOMINATING...ALL THE SHORT TERM MODELS SHOW THE SHOWERS MOVING
NO FARTHER S THAN THE CNDN BORDER IN LK SUP BEFORE EXITING TO THE E
BY 18Z. ALTHOUGH SCT-BKN MID CLDS MAY BRUSH NRN UPR MI MAINLY THIS
MRNG...THERE SHOULD BE NO OTHER IMPACT. THE HI PRES NOW IN THE MID
MS RIVER VALLEY IS FCST TO SHIFT TO THE SE GREAT LKS BY 0Z MON. THE
WSW H925-85 FLOW THIS AFTN ARND THIS FEATURE IS FCST TO LIFT H85
TEMPS UP TO ARND 12C OVER THE CWA. THE FCST DEEP MIXED LYR/NEARLY
ADIABATIC SFC-H75 LAPSE RATES SHOWN ON FCST SDNGS WARRANTS HI TEMPS
TOWARD THE HI END OF GUIDANCE AND NEAR 80 OVER THE SCENTRAL AWAY FM
LK MODERATION. WEAKER GRADIENT NEAR LK SUP ASSOCIATED WITH LINGERING
LO PRES TROF SHOULD ALLOW FOR SOME LK BREEZE NEAR LK SUP AND SOME
LOCAL COOLING...BUT THE WSW 15-20KT H925 FLOW SHOULD LIMIT THE
INLAND PENETRATION OF THE LK BREEZE. MORE MODERATION IS LIKELY NEAR
LK MI E OF ESCANABA. ALTHOUGH THERE MAY BE SOME HI BASED CU...THE
AFTN SHOULD BE MOSUNNY WITH MIN RH DIPPING TOWARD 30 PCT AS DEWPTS
MIX OUT INTO THE LO-MID 40S AWAY FM LK INFLUENCE. THE DEEP MIXING
MAY ALLOW FOR SOME WIND GUSTS TO 15-20 MPH...BUT FIRE WX SHOULD NOT
BE A CONCERN GIVEN RECENT GENEROUS RAINFALL.
TNGT...UPR MI WL BE DOMINATED BY A STRENGTHENING SSW FLOW UNDER
TIGHTENING PRES GRADIENT BTWN THE HI PRES RETREATING TOWARD NEW
ENGLAND AND LO PRES TAKING SHAPE SW OF LK WINNIPEG. ALTHOUGH THE
AIRMASS WL BE DRY/SKIES MOCLR WITH PWAT DROPPING AS LO AS 0.50-0.75
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 OVER THE INTERIOR SCENTRAL AND E WHERE THE PRES
GRADIENT WL BE A BIT WEAKER/WINDS LIGHTER.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 439 AM EDT SUN SEP 7 2014
DRY WITH SLIGHTLY ABOVE TEMPERATURES THROUGH TUESDAY MORNING...THEN
BECOMING COOL AND WET THROUGH AT LEAST THE END OF THE WORK WEEK.
WILL CONTINUE TO EXPERIENCE WAA ON MONDAY...ON INCREASING S WINDS AS
UPPER MI REMAINS STUCK BETWEEN A LARGE AREA OF HIGH PRESSURE EXITING
THE NEW ENGLAND STATES...AND AN ELONGATED TROUGH SET UP FROM THE
CENTRAL PLAINS THROUGH ONTARIO AND HUDSON BAY. 850MB TEMPS WILL
AVERAGE AROUND 11C BY THE END OF THE DAY. S GUSTS NEAR 20KTS WILL BE
COMMON IN THE AFTERNOON. MAY END UP WITH SLIGHTLY WARMER TEMPS THAN
FCST ALONG THE SHORES OF LAKE SUPERIOR THANKS TO THE DOWNSLOPE FLOW.
DESPITE THE GFS AND ECMWF LIGHT QPF OUTPUTS MONDAY EVENING...HAVE
KEPT THE FCST DRY FOR NOW...ASSOCIATED WITH A 500MB SHORTWAVE AHEAD
OF THE SFC TROUGH SET UP ACROSS MN.
LOOK FOR THE SFC TROUGH TO SET UP ACROSS THE CWA TUESDAY AFTERNOON
INTO TUESDAY EVENING. KEPT TS POTENTIAL TO A MINIMUM TUESDAY-TUESDAY
EVENING OVER MAINLY W UPPER MI. THE BEST CHANCE OF OF WIDESPREAD
PRECIPITATION WILL BE EARLY WEDNESDAY MORNING THROUGH THURSDAY
MORNING AS THE CENTRAL PLAINS LOW OVER KS AT 00Z WEDNESDAY DRIFTS NE
INTO W WI BY 12Z WEDNESDAY AND LIKELY SWINGS ACROSS N LAKE MI WHILE
STRENGTHENING AT 00Z THURSDAY...BEFORE EXITING ACROSS N LAKE HURON
WEDNESDAY EVENING. THE INITIAL SHORTWAVE WILL CROSS UPPER MI
WEDNESDAY EVENING. QPF MAY NEAR AN INCH FROM 06Z WEDNESDAY THROUGH
12Z THURSDAY. BEHIND THE EXITING LOW MUCH COLDER AIR WILL BE ABLE TO
SINK IN. 850MB TEMPS OF -2 TO -4C WILL BE POISED ACROSS MUCH OF THE
S CANADIAN PRAIRIES WEDNESDAY EVENING. A SECONDARY 500MB LOW OVER S
SASKATCHEWAN/MANITOBA AT 06Z THURSDAY WILL SLOWLY TRACK TO UPPER MI
BY 12Z FRIDAY. THE COOLER CANADIAN AIR WILL BE ABLE TO SLIP IN. 50S
WILL BE COMMON FOR HIGH TEMPS THURSDAY THROUGH SATURDAY. THE LAST
TIME WE HAD 50S FOR HIGHS WAS JULY 15TH AND 8TH. IT/S A GOOD BET
THAT THEY WILL BE BACK FOR THURSDAY THROUGH SATURDAY. GIVEN THE
FAVORABLE UPSLOPE N-NW FLOW...EXPECT LINGERING SHOWERS NEAR LAKE
SUPERIOR THROUGH THE END OF THE WORK WEEK...WITH LAKE ENHANCED
CLOUDS AND SHOWERS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 123 AM EDT SUN SEP 7 2014
ALTHOUGH A DISTURBANCE PASSING THRU NW ONTARIO WL BRING SOME MID
CLDS THIS MRNG TO MAINLY CMX...VFR CONDITIONS WL DOMINATE WITH LLVL
DRY AIR SHOWN ON 00Z LOCAL RAOBS IN PLACE OVER THE UPR LKS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 439 AM 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 WEAK TROUGH ACROSS LAKE SUPERIOR WILL SLOWLY DEEPEN
TUESDAY AFTERNOON...IN BETWEEN THE HUDSON BAY AND LOW PRESSURE
ORGANIZING ACROSS THE CENTRAL PLAINS. EXPECT THE CENTRAL PLAINS LOW
TO MOVE NE ACROSS THE UPPER GREAT LAKES WEDNESDAY AND WEDNESDAY
NIGHT...BEFORE EXITING INTO QUEBEC ON THURSDAY. AN EXTENDED PERIOD
OF N TO NW GALES WILL BE POSSIBLE WEDNESDAY INTO THURSDAY NIGHT.
&&
.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 MARQUETTE MI
324 AM EDT SUN SEP 7 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM EDT SUN SEP 7 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR LKS BTWN AN UPR RDG OVER WRN NAMERICA AND A TROF IN THE E. A
SHRTWV EMBEDDED IN THIS WNW FLOW IS LOCATED NEAR JAMES BAY EARLY
THIS MRNG. A RIBBON OF MSTR/CLD COVER/SOME SHOWERS IS NOTED ALONG
ITS ATTENDANT COLD FNT STRECHING SWWD TOWARD NRN LK SUP AND A WEAK
LO PRES CENTER RUNNING EWD ALONG THE MN/ONTARIO BORDER. THE THICKER
CLDS AND SHOWERS JUST N OF LK SUP APPEAR TO FORCED BY AREA OF H85-5
QVECTOR CNVGC DEPICTED BY THE SHORT TERM MODELS. UPR MI IS DOMINATED
BY A LLVL W FLOW BTWN THE COLD FNT/SFC LO AND HI PRES MOVING INTO
THE MID MS RIVER VALLEY. THE UPSTREAM 00Z INL RAOB IS FAIRLY DRY
WITH 00Z H85/H7 DEWPT DEPRESSIONS RUNNING AT 7C/8C.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON HOW FAR S THE
AREA OF CLDS/SHOWERS JUST N OF LK SUP WL MOVE AND TEMPS FOR THIS
AFTN/TNGT.
TODAY...AS THE SHRTWV NEAR JAMES BAY MOVES ESEWD THRU QUEBEC
TODAY...ITS ATTENDANT COLD FNT IS PROGGED TO SHIFT S THRU NRN LK SUP
BEFORE STALLING NEAR THE KEWEENAW. SINCE THE AREA OF QVECTOR CNVGC
FORCING THE THICKER CLDS/SHOWERS NOW IN ONTARIO IS FCST TO SHIFT
ESEWD OVER NRN LK SUP AND N OF THE LAND CWA WITH THE DRY H85-7 W
FLOW DOMINATING...ALL THE SHORT TERM MODELS SHOW THE SHOWERS MOVING
NO FARTHER S THAN THE CNDN BORDER IN LK SUP BEFORE EXITING TO THE E
BY 18Z. ALTHOUGH SCT-BKN MID CLDS MAY BRUSH NRN UPR MI MAINLY THIS
MRNG...THERE SHOULD BE NO OTHER IMPACT. THE HI PRES NOW IN THE MID
MS RIVER VALLEY IS FCST TO SHIFT TO THE SE GREAT LKS BY 0Z MON. THE
WSW H925-85 FLOW THIS AFTN ARND THIS FEATURE IS FCST TO LIFT H85
TEMPS UP TO ARND 12C OVER THE CWA. THE FCST DEEP MIXED LYR/NEARLY
ADIABATIC SFC-H75 LAPSE RATES SHOWN ON FCST SDNGS WARRANTS HI TEMPS
TOWARD THE HI END OF GUIDANCE AND NEAR 80 OVER THE SCENTRAL AWAY FM
LK MODERATION. WEAKER GRADIENT NEAR LK SUP ASSOCIATED WITH LINGERING
LO PRES TROF SHOULD ALLOW FOR SOME LK BREEZE NEAR LK SUP AND SOME
LOCAL COOLING...BUT THE WSW 15-20KT H925 FLOW SHOULD LIMIT THE
INLAND PENETRATION OF THE LK BREEZE. MORE MODERATION IS LIKELY NEAR
LK MI E OF ESCANABA. ALTHOUGH THERE MAY BE SOME HI BASED CU...THE
AFTN SHOULD BE MOSUNNY WITH MIN RH DIPPING TOWARD 30 PCT AS DEWPTS
MIX OUT INTO THE LO-MID 40S AWAY FM LK INFLUENCE. THE DEEP MIXING
MAY ALLOW FOR SOME WIND GUSTS TO 15-20 MPH...BUT FIRE WX SHOULD NOT
BE A CONCERN GIVEN RECENT GENEROUS RAINFALL.
TNGT...UPR MI WL BE DOMINATED BY A STRENGTHENING SSW FLOW UNDER
TIGHTENING PRES GRADIENT BTWN THE HI PRES RETREATING TOWARD NEW
ENGLAND AND LO PRES TAKING SHAPE SW OF LK WINNIPEG. ALTHOUGH THE
AIRMASS WL BE DRY/SKIES MOCLR WITH PWAT DROPPING AS LO AS 0.50-0.75
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 OVER THE INTERIOR SCENTRAL AND E WHERE THE PRES
GRADIENT WL BE A BIT WEAKER/WINDS LIGHTER.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 325 PM EDT SAT SEP 6 2014
ZONAL FLOW CONTINUES FOR MOST OF THIS FORECAST PERIOD WITH QUIET
WEATHER. A TROUGH SETS UP TO THE WEST ON TUE AND WILL HAVE SLIGHT
CHANCE POPS ACROSS THE WEST HALF. DID NOT MAKE TOO MANY CHANGES TO
THE GOING FORECAST AS TEMPERATURES AND WEATHER LOOKED GOOD.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE
WESTERN AND CENTRAL U.S. 12Z WED WITH THE TROUGH AMPLIFYING 12Z THU
AND MOVING INTO THE UPPER GREAT LAKES. THIS TROUGH STAYS OVER THE
THE AREA FRI AND 850 MB TEMPERATURES COOL TO -2C TO -4C AND WITH
LAKE SUPERIOR TEMPERATURES RUNNING AT 5C-15C...THIS WOULD BE ENOUGH
LAKE-850 MB DELTA-T FOR LAKE EFFECT CLOUDS AND SHOWERS. WHAT THIS
WILL MEAN IS SOME COLDER THAN NORMAL TEMPERATURES AND SHOWERY AND
WEATHER TYPICAL OF FALL AND WILL HAVE POPS IN THROUGH FRI NIGHT
BEFORE DRYING OUT ON SAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 123 AM EDT SUN SEP 7 2014
ALTHOUGH A DISTURBANCE PASSING THRU NW ONTARIO WL BRING SOME MID
CLDS THIS MRNG TO MAINLY CMX...VFR CONDITIONS WL DOMINATE WITH LLVL
DRY AIR SHOWN ON 00Z LOCAL RAOBS IN PLACE OVER THE UPR LKS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 240 PM EDT SAT SEP 6 2014
HIGH PRESSURE IN THE CENTRAL PLAINS WILL LIFT NORTHEAST THROUGH THE
LOWER GREAT LAKES ON SUNDAY AND THROUGH THE NEW ENGLAND STATES ON
MONDAY. BEING ON THE EDGE OF THE RIDGE ASSOCIATED WITH THE
HIGH...THE UPPER GREAT LAKES REGION WILL OCCASIONALLY SEE WINDS UP
TO 20-25KTS THROUGH THIS EVENING BEFORE BECOMING LIGHT ON
SUNDAY. BUT WITH THE HIGH DEPARTING...SOUTHERLY WINDS WILL BE ON THE
INCREASE SUNDAY NIGHT AND REMAIN UP TO 20KTS INTO TUESDAY. A STRONG
LOW PRESSURE SYSTEM LIFTING OUT OF THE CENTRAL PLAINS ON TUESDAY
NIGHT WILL MOVE THROUGH THE UPPER GREAT LAKES REGION WEDNESDAY
EVENING BEFORE REACHING JAMES BAY BY THURSDAY EVENING. WITH LAKE
SUPERIOR EXPECTED TO BE ON THE NORTH SIDE OF THIS
LOW...NORTH-NORTHEAST WINDS OF 25-30KTS (WITH OCCASIONAL GALE FORCE
GUSTS TO 35KTS) WILL OCCUR OVER MUCH OF THE LAKE WEDNESDAY INTO
THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...07
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
143 AM EDT SUN SEP 7 2014
.SYNOPSIS...
EXPECT WET CONDITIONS THROUGH MONDAY AS WAVES OF SHOWERS AND
THUNDERSTORMS WITH HEAVY RAINFALL OCCASIONALLY PUSH ACROSS THE AREA.
THIS IN RESPONSE TO A SLOW MOVING COLD FRONT DROPPING SOUTHEAST AND
AN AREA OF LOW PRESSURE SLOWLY MOVING UP ALONG THE FRONT. THE LOW
WILL EXIT THE REGION LATE MONDAY NIGHT...FOLLOWED BY A GRADUAL
WARMING AND DRYING TREND MID AND LATE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 1100 PM SATURDAY...HAVE MASSAGED THE POPS FROM THE PREVIOUS
UPDATE...WITH AN INCREASING COVERAGE OF ONSHORE MOVING CONVECTION.
GOOD CHANCE TO LIKELY POP CATEGORIES FOR THE IMMEDIATE COAST BY
DAYBREAK SUN...LOWERING AS ONE PROGRESSES INLAND. THE TROPICAL
REGIME WARRANTS A SLIGHT TWEAK UPWARDS OF THE SFC DEWPOINTS BASED
ON LATEST OBS AND TRENDS.
&&
.SHORT TERM /6 AM SUNDAY MORNING 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 /06Z SUNDAY THROUGH THURSDAY/...
AS OF 06Z...SHOWERS OFFSHORE ARE INCREASING IN COVERAGE...SO HAVE
INCLUDED VCSH/TEMPO -SHRA FOR ALL COASTAL TERMS THIS MORNING. CIGS
WILL LIKELY BOUNCE AROUND BETWEEN MVFR/VFR AT THESE SITES AS WELL.
INCREASING MID LEVEL CLOUDS AHEAD OF THE ADVANCING COLD FRONT SHOULD
LIMIT FOG/STRATUS POTENTIAL FOR KFLO/KLBT...BUT A BRIEF PERIOD OF
MVFR/IFR CIGS CANNOT BE RULED OUT AROUND DAYBREAK. EXPECT WIDESPREAD
SHOWERS DURING THE DAY AS MOIST TROPICAL AIR STREAMS ONSHORE AND IS
LIFTED BY AN APPROACHING COLD FRONT. THERE WILL LIKELY BE PERIODS OF
MVFR/IFR VSBYS IN LOCALLY HEAVIER SHOWERS...BUT STILL TOO EARLY TO
PINPOINT THE TIMING OF THESE RESTRICTIONS. EXPECT SCT/BKN 2KFT
STRATOCU WILL PERSIST FOR MUCH OF THE DAY AS WELL...WITH MVFR CIGS
MOST LIKELY ALONG THE COAST WITH THE HEAVIER PCPN. SHOWERS WILL
CONTINUE THROUGH THE EVENING HOURS AS AN AREA OF LOW PRESSURE SLOWLY
MOVES UP THE SOUTH CAROLINA COAST. SOUTH WINDS AROUND 10 KT ALONG
THE COAST WILL SHIFT TO THE SOUTHEAST LATE IN THE PERIOD. INLAND...
EAST WINDS LESS THAN 10 KT WILL BECOME NORTHEAST AFTER 00Z MON.
EXTENDED OUTLOOK...SHOWERS WITH PERIODS OF MVFR CIGS AND MVFR/IFR
VSBYS THROUGH MONDAY. VFR TUESDAY THROUGH THURSDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1115 PM SATURDAY...BORDERLINE SCEC CONDITIONS REMAIN AND
WILL CONTINUE WITH IT THRU 600 PM SUNDAY. LATEST HRRR CONTINUES TO
SUPPORT WIND-WISE WITH RESULTING SEAS FOLLOWING.
PCPN COVERAGE CONTINUES TO INCREASE ACROSS THE ADJACENT ATL
WATERS. TRAJECTORIES SO FAR SHOW THE PCPN MOVING MAINLY PARALLEL
TO THE ILM COAST...AND NOT DIRECTLY ONSHORE. HOWEVER...AS THE
WEAKNESS SFC AND ALOFT ALONG THE SC-GA COAST MOVES SLOWLY NE-
WARD...EXPECT THE ATL PCPN BEGIN TO TRACK MORE NORTHERLY OR EVEN
NNW. AS A RESULT...THE CONVECTION WILL BECOME MORE WIDESPREAD
ACROSS THE ILM WATERS THRU DAYBREAK.
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.
&&
$$
NEAR TERM...DCH/III
SHORT TERM...TRA
LONG TERM...RGZ
AVIATION...BJR/RJD
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
459 AM CDT SUN SEP 7 2014
.SHORT TERM...
(Today and Tonight)
Showers are occurring across our central and northern counties, in a
rather moist airmass north of a stalled frontal boundary. The most
noteworthy is a persistent east-west band of showers with moderate
to heavy rain, extending from just east of San Angelo to just south
of Brownwood. The HRRR and TTU WRF pick up on these showers to some
extent, with a trend of dissipation between 12Z and 15Z. May need to
extend the higher PoPs from the overnight period past 12Z this
morning. Will monitor radar trends and update if needed.
During the day today, have a possibility for scattered showers and a
few thunderstorms in the moist airmass. Considerable cloud cover
will hold through early afternoon, and then should have a decrease
in cloud cover from the west and southwest later in the afternoon.
The extent and duration of cloud cover is expected to have an effect
on temperatures today. Going with highs in the lower to mid 80s.
Have a lingering slight chance PoP early tonight for our central and
southern counties. Otherwise, a decrease in cloud cover is expected
overnight. Given the recent rainfall and a moist airmass, will have
a possibility for patchy fog development late tonight, depending on
the extent of clearing. Temperatures will cool to near dewpoint
values overnight with light (southeast) winds.
.LONG TERM...
(Monday through next Sunday)
...A strong cold front will bring much cooler temperatures and
another chance of rainfall to the area by the end of the week...
South winds and much warmer temperatures return to the area Monday
through Wednesday, as a lee surface trough develops ahead of an
upper level trough moving east across the Rockies. Temperatures on
Monday will be near seasonal norms for this time of year, with
afternoon highs in the lower 90s. An isolated shower or thunderstorm
will be possible across far southeast counties during the
afternoon, otherwise dry conditions will prevail. Breezy south to
southwest winds and above normal temperatures return to the area
Tuesday and Wednesday with highs both days in the mid and upper
90s.
Big changes coming towards the end of the week as the aforementioned
upper trough tracks east across the Plains, sending a strong cold
front south across our area on Thursday. It will feel more like
fall behind the front Friday and Saturday with high temperatures
only in the middle/upper70s to lower 80s, with overnight lows in
the lower to middle 60s. We`ll also see another chance for showers
and thunderstorms along and behind the front Thursday into Friday.
Kept chance POPs in the forecast for now, but will likley need to
be raised further as model confidence increases. Below normal
temperatures continue for next Sunday but it will be a liitle
warmer with highs mainly in the middle 80s.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 83 68 92 73 95 / 50 10 10 5 5
San Angelo 84 68 92 71 95 / 60 20 10 5 5
Junction 85 69 91 71 94 / 40 20 10 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
19/JW
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
240 AM CDT SUN SEP 7 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 240 AM CDT SUN SEP 7 2014
CURRENTLY AS OF 07Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED NORTHWEST FLOW FROM BRITISH COLUMBIA THROUGH THE GREAT LAKES
REGION...THOUGH A FAIRLY POTENT TROUGH WAS BEGINNING TO BUCK THIS
FLOW DROPPING SOUTH THROUGH BRITISH COLUMBIA. THE NORTHWEST FLOW HAS
HELPED PRODUCE A DRYING...SUBSIDENT REGIME OVER THE FORECAST
AREA...SEEN NICELY ON REGIONAL 00Z SOUNDINGS AS WELL AS PRECIPITABLE
WATER PLOTS SHOWING BETWEEN 0.5-0.75 INCHES OR 50-90 PERCENT OF
NORMAL. THIS DRY AIR HAS RESULTED IN BASICALLY CLEAR SKIES ACROSS
THE ENTIRE UPPER MIDWEST. SURFACE PATTERN FEATURES HIGH PRESSURE
CENTERED OVER THE MID MISSISSIPPI VALLEY WITH A WARM FRONT FROM
NORTHERN MN SOUTHWESTWARD INTO WYOMING. LIGHT SURFACE WINDS
ASSOCIATED WITH THE HIGH...CLEAR SKIES AND DRY AIR HAS ALLOWED FOR
TEMPERATURES TO DIP INTO THE MID 40S AT THE TYPICAL COLD SPOTS IN
CENTRAL WI. ABOVE THE SURFACE...HOWEVER...TEMPERATURES ARE WARMING
DUE TO A DOWNSLOPE WESTERLY FLOW FROM THE MOUNTAINS. 925MB TEMPS ARE
16-18C PER LATEST RAP ANALYSIS COMPARED TO AROUND 12C 24 HOURS AGO.
QUIET CONDITIONS LOOK TO CONTINUE FOR THE NEXT 24 HOURS AS THE
REGION REMAINS UNDER THE INFLUENCE OF THE SURFACE HIGH AND THE DRY
AIR ASSOCIATED WITH IT. STILL AT 12Z MONDAY...PRECIPITABLE WATER
PROGS ONLY SHOW VALUES OF 0.5-0.75 INCHES ACROSS THE REGION. IT
SHOULD BE NOTED THAT THE SURFACE HIGH DOES DRIFT OFF TO THE
EAST...WHICH ALLOWS FOR A RETURN FLOW TO DEVELOP ACROSS THE PLAINS.
THIS RETURN FLOW HELPS PULL A SURGE OF 1-1.25 INCH PRECIPITABLE
WATER THROUGH THE PLAINS INTO SOUTHWEST MN BY 12Z MONDAY.
ADDITIONALLY...A SHORTWAVE TRACKING THROUGH SOUTH DAKOTA TONIGHT
SHOULD RESULT IN SHOWERY CONVECTION BREAKING OUT AROUND THE SIOUX
FALLS AREA. SOME CIRRUS SPREADING OFF THIS PRECIPITATION LOOKS TO
SPREAD INTO THE AREA AFTER MIDNIGHT.
925MB TEMPS ARE PROGGED TO CHANGE VERY LITTLE TODAY FROM WHERE THEY
ARE NOW...HOLDING IN THAT 16-18C RANGE. STILL...THESE ARE 2-4C
WARMER THAN WHAT WE STARTED OFF WITH AT 12Z SATURDAY. THUS WITH
PLENTY OF SUN AGAIN HIGHS SHOULD END UP A COUPLE DEGREES WARMER. AN
INCREASING SOUTHWEST FLOW TONIGHT WILL HELP TEMPERATURES STAY A BIT
WARMER AS WELL...ESPECIALLY OVER THE HIGHER TERRAIN ALONG/WEST OF
THE MS RIVER WHERE A TIGHTER GRADIENT EXISTS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 240 AM CDT SUN SEP 7 2014
THE SHORTWAVE THAT COMES ACROSS SOUTH DAKOTA TONIGHT LOOKS TO SLIDE
ACROSS THE FORECAST AREA ON MONDAY...BRINGING THE SURGE OF SOMEWHAT
HIGHER PRECIPITABLE WATER INTO THE REGION AND THE ASSOCIATED SHOWERS
AS WELL. ITS HARD TO SAY HOW MUCH OF THE SHOWER ACTIVITY WILL MOVE
INTO THE AREA GIVEN THE INITIAL DRY AIRMASS IN PLACE. THIS IS
REFLECTED WELL IN THE 07.00Z NAM KEEPING THE FORECAST AREA DRY AND
SREF TRENDS THROUGH THE DAY DRYING THE PRECIPITATION UP. THE
TYPICALLY WETTER GFS SPREADS PRECIPITATION INTO THE WESTERN FORECAST
AREA...BUT SOUNDINGS ARE ALSO RELATIVELY DRY. FOR NOW...HAVE
CONFINED ANY PRECIPITATION CHANCES TO AFTER 18Z WEST OF THE MS RIVER
AND KEPT THE CHANCES AROUND 20. GIVEN THAT THE INSTABILITY AXIS
LOOKS TO STAY WEST OF I-35 DURING THE DAY...DO NOT HAVE ANY THUNDER
MENTIONED. A BETTER SHOT FOR PRECIPITATION EXISTS MONDAY NIGHT...
MAINLY ACROSS IOWA...AS ANOTHER WEAK SHORTWAVE MOVES THROUGH THAT
STATE AND THE NOSE OF A SURGE OF 850MB MOISTURE TRANSPORT POINTS IN
FOR A TIME. TEMPERATURES ON MONDAY LOOK SIMILAR TO TODAY GIVEN
SIMILAR 925MB TEMPS...POTENTIAL FOR SOME SUN AND A SOUTHERLY BREEZE
FOR MIXING. LOWS MONDAY NIGHT SHOULD BE NOTICEABLY WARMER WITH
HIGHER DEWPOINTS...CONTINUED SOUTHERLY BREEZE AND CLOUD COVER ALL
HELPING TO KEEP TEMPS UP.
THE MIDDLE OF THE WEEK CONTINUES TO BE THE ACTIVE PERIOD OF THE
FORECAST...CAUSED BY A VARIETY OF UPPER LEVEL FEATURES INFLUENCING
OR IMPACTING THE AREA. THE FIRST FEATURE IS THE CURRENT SHORTWAVE
TROUGH DROPPING THROUGH BRITISH COLUMBIA WHICH DIGS INTO THE HIGH
PLAINS TUESDAY NIGHT...SETTING UP SOUTHWEST UPPER FLOW AND A STRONG
INCREASE IN LOW LEVEL RETURN FLOW TOWARDS THE AREA. THE SECOND
FEATURE IS A COLLECTION OF SHORTWAVES THAT DEVELOP OFF THE COLORADO
MOUNTAINS ON TUESDAY...WHICH GET CAUGHT UP IN THE SOUTHWEST FLOW AND
LIFTED INTO THE FORECAST AREA TUESDAY NIGHT. THE 07.00Z NAM AND
ECMWF EVEN SUGGESTS THESE SHORTWAVES WILL PHASE WITH THE
AFORMENTIONED TROUGH. THE THIRD FEATURE IS A PLUME OF EAST PACIFIC
TROPICAL MOISTURE SEEN EAST OF HURRICANE NORBERT ON WATER VAPOR...
WHICH LOOKS TO GET PULLED UP INTO THE FORECAST AREA ALSO ON TUESDAY
NIGHT.
AS THE AFOREMENTIONED DISCUSSION HIGHLIGHTS...TUESDAY NIGHT IS THE
CENTER POINT FOR PRECIPITATION. ALTHOUGH THERE ARE STILL SOME SLIGHT
MODEL DIFFERENCES...PARTICULARLY WITH TRACK AND TIMING OF THE
SURFACE SYSTEM...ALL MODELS REMAIN CONSISTENT IN SPREADING SHOWERS
AND EMBEDDED STORMS INTO THE REGION TUESDAY NIGHT. THEREFORE...HAVE
CONTINUED TO RAISE PRECIPITATION CHANCES. CAPE IS FAIRLY MEAGER
GIVEN LAPSE RATES NOT MUCH HIGHER THAN MOIST ADIABATIC...WHICH WILL
LIMIT SEVERE WEATHER. ON THE OTHER HAND...WARM CLOUD DEPTHS
APPROACHING 4-4.5 KM...PRECIPITABLE WATER CLIMBING TO 2 INCHES AND
STRONG 850MB MOISTURE TRANSPORT NOSING INTO THE AREA FAVOR HEAVY
RAINFALL POTENTIAL. LUCKILY THE FLOW LOOKS PROGRESSIVE ENOUGH TO
PREVENT FLOODING. WEDNESDAY IS TRICKY AS THE SYSTEM COULD BE HEADING
OFF TO THE EAST...ALLOWING DRIER AND SUBSIDENT AIR TO INFILTRATE THE
REGION. STILL A CONSENSUS EXISTS FOR SHOWERS AND STORMS TO BE AROUND
ACROSS WISCONSIN. IF THE SYSTEM WOULD SLOW UP...THERE WOULD BE AN
OPPORTUNITY FOR DESTABILIZATION AND SEVERE WEATHER GIVEN STRONG WIND
FIELD. HOWEVER...THIS SEEMS TO BE A VERY LOW PROBABILITY AT THIS
POINT. IN THE RAINFALL DEPARTMENT...LOOKS LIKE WE SHOULD PICK UP 1-2
INCHES FROM THIS SYSTEM.
IN THE WAKE OF THE SYSTEM...ITS ALL ABOUT THE COLD AIR. THE FIRST
SURGE COMES THROUGH WEDNESDAY NIGHT WITH 925MB TEMPS DROPPING TO 4-
6C BY 12Z THURSDAY. THIS CAUSES BOTH LOWS WEDNESDAY NIGHT AND HIGHS
ON THURSDAY TO TAKE A BIG HIT. EVEN COLDER AIR SURGES IN FOR
FRIDAY...RESULTING FROM AN UPPER TROUGH SWINGING ACROSS THE AREA.
THIS FEATURE SENDS 925MB TEMPS DOWN TO 2-4C BY 12Z FRI WITH ONLY
SLIGHT MODERATION DURING THE DAY. A BRISK NORTHWEST WIND COMBINED
WITH SOME POTENTIAL FOR SHOWERS...PARTICULARLY NORTH OF I-90
WEDNESDAY NIGHT AND THURSDAY NIGHT INTO FRIDAY...WILL REALLY MAKE IT
FEEL LIKE FALL. HIGH PRESSURE THEN LOOKS TO BUILD IN FOR FRIDAY
NIGHT...WHICH WOULD APPEAR TO STAND THE BEST CHANCE FOR FROST
FORMATION IN LIKELY THE TYPICAL COLD SPOTS. DRY CONDITIONS AND SLOW
MODERATION OF TEMPERATURES ARE EXPECTED ON SATURDAY AS THE
UPPER TROUGH EXISTS AND SUNSHINE HELPS WARM THE AIRMASS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1146 PM CDT SAT SEP 6 2014
HIGH PRESSURE OVER IOWA WILL SLOWLY SLIDE EAST DURING THE NEXT 24
HOURS...MAINTAINING A GENERAL WESTERLY TO SOUTHWESTERLY BREEZE
AT THE TAF SITES. EXPECT THIS BREEZE TO HOLD DRY AIR IN PLACE...
RESULTING IN VFR CONDITIONS AND REALLY VERY LITTLE CLOUD COVER.
THE ONLY CONCERN WOULD BE VALLEY FOG AT LSE THIS MORNING. A
STRATUS DECK WAS FORMING OVER THE MS RIVER BETWEEN 04-05Z DUE TO
CLEAR SKIES...LIGHT WINDS THROUGHOUT THE VALLEY AND COOLING
TEMPERATURES. HOWEVER...THOSE WINDS LOOK TO INCREASE IN A FEW
HOURS TO 10 TO 20 KT RIGHT ABOVE THE SITE IN THE VALLEY. THIS WIND
SHOULD PROHIBIT ANY FOG FROM FORMING AT LSE AND MAY EVEN CAUSE THE
STRATUS TO CLEAR OUT. NEARBY VALLEYS WHICH HAVE MORE SHELTERING
SHOULD SEE FOG AND THUS VCFG REMAINS MENTIONED IN THE LSE TAF. DID
ADD A MENTION OF SCT LIFR STRATUS WITH THE VCFG TO REFLECT CURRENT
CONDITIONS...THOUGH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...AJ
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
440 AM PDT SUN SEP 7 2014
...AVIATION DISCUSSION UPDATED...
.SYNOPSIS...
INCREASING MOISTURE OVER THE REGION FROM TROPICAL CYCLONE NORBERT
WILL BRING A CHANCE OF SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS TO MUCH OF LOS ANGELES AND VENTURA COUNTIES THROUGH
TUESDAY...AND TO SANTA BARBARA COUNTY SUNDAY NIGHT INTO MONDAY
MORNING. A COOLER WEATHER PATTERN CAN BE EXPECTED MONDAY AND
TUESDAY...FOLLOWED BY WARMING BY THE END OF THE WEEK.
&&
.SHORT TERM (TODAY-TUESDAY)...
TROPICAL CYCLONE NORBERT CONTINUES TO WEAKEN THIS MORNING AS IT
MOVES INTO COOLER OCEAN WATERS. MOISTURE ASSOCIATED WITH THE
SYSTEM WILL MOVE NORTH INTO THE AREA. GPS INTEGRATED PRECIPITABLE
WATER SENSORS ARE CLIMBING THIS MORNING ACROSS THE AREA UP TO
AROUND 1 INCH...WHICH IS IN-LINE WITH GOES SOUNDER PRECIPITABLE
WATER IMAGERY. A DEVELOPING CLOUD MASS CAN BE SEEN ON INFRARED
IMAGERY ALONG THE UNITED STATES-MEXICO BORDER. THIS CLOUD MASS
WILL SPREAD NORTH INTO THE AREA LATER THIS MORNING. A PARTLY TO
MOSTLY CLOUDY DAY LOOKS ON TAP FOR MOST AREAS. MODEL SOLUTIONS
ARE STRUGGLING SOMEWHAT WITH THE TRANSPORT OF THE MOISTURE NORTH.
00Z NAM-WRF STRUGGLED DUE TO POSSIBLE CONVECTIVE FEEDBACK AS SUPER
DRY 850 MB DEWPOINTS HAVE DEVELOPED IN THE MODEL. RAP SOLUTIONS
HAVE BEEN THE MOST CONSISTENT WITH HANDLING THE MOISTURE IN THE
FIRST TWO PERIODS...ILLUSTRATING PRECIPITABLE WATER VALUES AROUND
1.5 INCH BY THIS AFTERNOON. EMBEDDED SPRINKLES OR ISOLATED SHOWERS
AND THUNDERSTORMS WILL LIKELY DEVELOP THIS AFTERNOON ACROSS THE
COASTAL AND VALLEY AREAS...WITH SCATTERED SHOWERS AND
THUNDERSTORMS EXPECTED IN THE MOUNTAINS AND DESERT. LOCALIZED
FLASH FLOODING WILL BE POSSIBLE TODAY AS STEERING WINDS ARE JUST
STRONG ENOUGH TO KEEP STORMS MOVING FAIRLY RAPIDLY ACROSS THE
AREA. IF THE DATA DOES CHANGE...FUTURE SHIFTS COULD DECIDE TO
ISSUE A FLASH FLOOD WATCH AS ENOUGH MOISTURE IS PRESENT.
STEERING WINDS LIGHTEN ON MONDAY AND THIS COULD POSE A PROBLEM AS
THE MOISTURE HANGS AROUND. PRECIPITABLE WATER VALUES IN THE NAM-
WRF AND GFS SOLUTIONS APPROACH 2 INCHES AS THE MOIST AIR MASS
SPREADS NORTH. A FLASH FLOOD WATCH COULD BE ISSUED A LATER TIME
FOR MONDAY AND MONDAY EVENING IF THIS DATA HOLDS TRUE FOR SEVERAL
MORE MODEL RUNS. WITH THE MOIST AIR MASS SPREADING NORTH AND
LIKELY A CLOUD SHIELD IN PLACE...TEMPERATURES WERE COOLED SOME
WHAT FOR MONDAY...AND AGAIN ON TUESDAY.
THE WEATHER PATTERN GET MORE CONVOLUTED ON TUESDAY AS A TROUGH OFF
THE NORTH COAST OF CALIFORNIA DROPS SOUTH. MODEL SOLUTIONS
CONTINUE TO SUGGEST MOISTURE FROM NORBERT HANGING AROUND OVER LOS
ANGELES AND VENTURA COUNTIES. THIS MOISTURE COULD GET CAUGHT UP
THE DYNAMIC OF THE TROUGH AS IT APPROACHES THE AREA...AND BRING
ADDITIONAL SHOWERS TO THE AREA. POPS AND WEATHER WERE INTRODUCED
FROM MONDAY NIGHT THROUGH TUESDAY MORNING. TEMPERATURES WERE
COOLED ADDITIONAL DUE TO THE POSSIBILITY OF CLOUD COVER AND
EVAPORATIVE COOLING TAKING PLACE.
.LONG TERM (WEDNESDAY-SATURDAY)...
WEDNESDAY LOOKS DRIER AS THE REMNANT CIRCULATION FROM NORBERT
MOVES EAST AND THE TROUGH PUSHES THE MOISTURE SOUTH AND EAST OF
THE AREA...BUT GFS AND ECMWF SOLUTIONS ARE STARTING TO COME INTO
AGREEMENT FOR A DEVELOPING EASTERLY WAVE TO BRING ADDITIONAL
MOISTURE BACK INTO SOUTHERN CALIFORNIA BETWEEN THURSDAY AND
SATURDAY. WITH THIS BEING A NEW FEATURE...POPS HAVE BUMPED UP AT
THIS POINT FOR THE MOUNTAINS AND DESERT...HOWEVER...NO MENTION OF
SHOWERS OR THUNDERSTORMS EXISTS AT THIS TIME. WHILE A WARMING
TREND IS REFLECTED FOR LATE NEXT WEEK...WEDNESDAY COULD END UP
BEING THE WARMEST DAY IF THE ECMWF AND GFS SOLUTIONS PLAY OUT.
&&
.AVIATION...07/06Z.
NORTH OF POINT CONCEPTION...MODERATE TO HIGH CONFIDENCE IN THE 12Z
TAFS. VLIFR TO LIFR CONDITIONS WILL DEVELOP AT COASTAL SITES THIS
MORNING AND DIMINISH 17Z-19Z. IFR-MVFR MAY REDEVELOP AT SOME COASTAL
SITES TONIGHT AND WILL DEPEND UPON HOW QUICKLY MID LEVEL CLOUD COVER
FROM HURRICANE NORBERT MOVES INTO THE REGION. OTHERWISE AND
ELSEWHERE VFR CONDITIONS WILL PREVAIL.
SOUTH OF POINT CONCEPTION...LOW TO MODERATE CONFIDENCE IN THE 12Z
TAFS. DUE TO MOISTURE FROM HURRICANE NORBERT SPREADING NORTH... MID
LEVEL CLOUD COVER IS HELPING TO RETARD SURFACE CLOUD DEVELOPMENT AND
THIS SHOULD OCCUR AGAIN TOMORROW NIGHT. A TWENTY PERCENT CHANCE OF
IFR-MVFR CONDITIONS DEVELOPING AT COASTAL SITES AND ADJACENT VALLEYS
BY 16Z. AFTER 16Z...THERE IS A SLIGHT CHANCE OF SHOWERS DEVELOPING
AT LOS ANGELES COUNTY SITES... WITH A SLIGHT CHANCE OF THUNDERSTORMS
AFTER 18Z. OTHERWISE AND ELSEWHERE VFR CONDITIONS WILL PREVAIL.
KLAX...LOW TO MODERATE CONFIDENCE IN THE 12Z TAF DUE TO MOISTURE
FROM HURRICANE NORBERT SPREADING NORTHWARD. THE MID LEVEL CLOUD
COVER SHOULD HELP TO RETARD SURFACE CLOUD DEVELOPMENT THOUGH THERE
IS A FIFTEEN PERCENT CHANCE OF IFR-MVFR CONDITIONS DEVELOPING BY
16Z. DURING THE PERIOD 20Z-05Z...THERE IS A SLIGHT CHANCE OF
THUNDERSTORMS. OTHERWISE VFR CONDITIONS WILL PREVAIL.
KBUR...LOW TO MODERATE CONFIDENCE IN THE 12Z TAF DUE TO MOISTURE
FROM HURRICANE NORBERT SPREADING NORTH. THE MID LEVEL CLOUD COVER
SHOULD HELP TO RETARD SURFACE CLOUD DEVELOPMENT. A TEN PERCENT
CHANCE OF MVFR CONDITIONS DEVELOPING BY 16Z. AFTER 18Z...THERE IS A
SLIGHT CHANCE OF THUNDERSTORMS. OTHERWISE VFR CONDITIONS WILL
PREVAIL.
&&
.MARINE...07/300 AM.
HIGH CONFIDENCE IN A SMALL CRAFT ADVISORY THAT IS IN EFFECT FOR THE
OUTER WATERS THROUGH LATE MONDAY NIGHT FOR NORTHWEST WINDS GUSTING
TO 25 KNOTS. THE STRONGEST WINDS ARE EXPECTED BETWEEN POINT
CONCEPTION AND SAN NICOLAS ISLAND. FOR THE INNER WATERS...
CONDITIONS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS
THROUGH AT LEAST MID-WEEK.
HURRICANE NORBERT WILL AFFECT THE COASTAL WATERS THROUGH MONDAY WITH
LARGE SWELLS AND A SLIGHT CHANCE OF ISOLATED SHOWERS AND
THUNDERSTORMS. THE BEST CHANCE FOR CONVECTIVE WEATHER IS OFF THE LOS
ANGELES COUNTY COAST WITH CHANCES LESSENING TO THE NORTH. A MARINE
WEATHER STATEMENT HAS BEEN ISSUED TO ADDRESS THE POTENTIAL
CONVECTIVE WEATHER.
&&
.BEACHES...07/300 AM.
A BEACH HAZARD STATEMENT IS IN EFFECT THROUGH LATE MONDAY NIGHT FOR
VENTURA AND LOS ANGELES COUNTIES DUE TO HIGH SURF... HIGH RIP
CURRENT RISK... AND POSSIBLE MINOR COASTAL FLOODING NEAR EVENING
HIGH TIDE.
THE SOUTHERN HEMISPHERE SWELL WILL SLOWLY DIMINISH IN HEIGHT AND
PERIOD TODAY JUST AS THE EFFECTS OF HURRICANE NORBERT ARRIVE. THE
HURRICANE SWELL PERIOD WILL BE SHORTER... NEAR 11 SECONDS... BUT
WILL KEEP THE SURF ELEVATED FOR AN ADDITIONAL DAY. THE STRONG RIP
CURRENTS MAY CONTINUE THROUGH TUESDAY THOUGH SWELL AND SURF IS
SUBSIDING EARLIER.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY (SEE LAXNPWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
BEACH HAZARDS STATEMENT (SEE LAXCFWLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).
&&
$$
PUBLIC...HALL
AVIATION...KJ
BEACHES/MARINE....KJ
SYNOPSIS...HALL/SIRARD
WWW.WEATHER.GOV/LOSANGELES
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
343 AM PDT SUN SEP 7 2014
.SYNOPSIS...
INCREASING MOISTURE OVER THE REGION FROM TROPICAL CYCLONE NORBERT
WILL BRING A CHANCE OF SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS TO MUCH OF LOS ANGELES AND VENTURA COUNTIES THROUGH
TUESDAY...AND TO SANTA BARBARA COUNTY SUNDAY NIGHT INTO MONDAY
MORNING. A COOLER WEATHER PATTERN CAN BE EXPECTED MONDAY AND
TUESDAY...FOLLOWED BY WARMING BY THE END OF THE WEEK.
&&
.SHORT TERM (TODAY-TUESDAY)...
TROPICAL CYCLONE NORBERT CONTINUES TO WEAKEN THIS MORNING AS IT
MOVES INTO COOLER OCEAN WATERS. MOISTURE ASSOCIATED WITH THE
SYSTEM WILL MOVE NORTH INTO THE AREA. GPS INTEGRATED PRECIPITABLE
WATER SENSORS ARE CLIMBING THIS MORNING ACROSS THE AREA UP TO
AROUND 1 INCH...WHICH IS IN-LINE WITH GOES SOUNDER PRECIPITABLE
WATER IMAGERY. A DEVELOPING CLOUD MASS CAN BE SEEN ON INFRARED
IMAGERY ALONG THE UNITED STATES-MEXICO BORDER. THIS CLOUD MASS
WILL SPREAD NORTH INTO THE AREA LATER THIS MORNING. A PARTLY TO
MOSTLY CLOUDY DAY LOOKS ON TAP FOR MOST AREAS. MODEL SOLUTIONS
ARE STRUGGLING SOMEWHAT WITH THE TRANSPORT OF THE MOISTURE NORTH.
00Z NAM-WRF STRUGGLED DUE TO POSSIBLE CONVECTIVE FEEDBACK AS SUPER
DRY 850 MB DEWPOINTS HAVE DEVELOPED IN THE MODEL. RAP SOLUTIONS
HAVE BEEN THE MOST CONSISTENT WITH HANDLING THE MOISTURE IN THE
FIRST TWO PERIODS...ILLUSTRATING PRECIPITABLE WATER VALUES AROUND
1.5 INCH BY THIS AFTERNOON. EMBEDDED SPRINKLES OR ISOLATED SHOWERS
AND THUNDERSTORMS WILL LIKELY DEVELOP THIS AFTERNOON ACROSS THE
COASTAL AND VALLEY AREAS...WITH SCATTERED SHOWERS AND
THUNDERSTORMS EXPECTED IN THE MOUNTAINS AND DESERT. LOCALIZED
FLASH FLOODING WILL BE POSSIBLE TODAY AS STEERING WINDS ARE JUST
STRONG ENOUGH TO KEEP STORMS MOVING FAIRLY RAPIDLY ACROSS THE
AREA. IF THE DATA DOES CHANGE...FUTURE SHIFTS COULD DECIDE TO
ISSUE A FLASH FLOOD WATCH AS ENOUGH MOISTURE IS PRESENT.
STEERING WINDS LIGHTEN ON MONDAY AND THIS COULD POSE A PROBLEM AS
THE MOISTURE HANGS AROUND. PRECIPITABLE WATER VALUES IN THE NAM-
WRF AND GFS SOLUTIONS APPROACH 2 INCHES AS THE MOIST AIR MASS
SPREADS NORTH. A FLASH FLOOD WATCH COULD BE ISSUED A LATER TIME
FOR MONDAY AND MONDAY EVENING IF THIS DATA HOLDS TRUE FOR SEVERAL
MORE MODEL RUNS. WITH THE MOIST AIR MASS SPREADING NORTH AND
LIKELY A CLOUD SHIELD IN PLACE...TEMPERATURES WERE COOLED SOME
WHAT FOR MONDAY...AND AGAIN ON TUESDAY.
THE WEATHER PATTERN GET MORE CONVOLUTED ON TUESDAY AS A TROUGH OFF
THE NORTH COAST OF CALIFORNIA DROPS SOUTH. MODEL SOLUTIONS
CONTINUE TO SUGGEST MOISTURE FROM NORBERT HANGING AROUND OVER LOS
ANGELES AND VENTURA COUNTIES. THIS MOISTURE COULD GET CAUGHT UP
THE DYNAMIC OF THE TROUGH AS IT APPROACHES THE AREA...AND BRING
ADDITIONAL SHOWERS TO THE AREA. POPS AND WEATHER WERE INTRODUCED
FROM MONDAY NIGHT THROUGH TUESDAY MORNING. TEMPERATURES WERE
COOLED ADDITIONAL DUE TO THE POSSIBILITY OF CLOUD COVER AND
EVAPORATIVE COOLING TAKING PLACE.
.LONG TERM (WEDNESDAY-SATURDAY)...
WEDNESDAY LOOKS DRIER AS THE REMNANT CIRCULATION FROM NORBERT
MOVES EAST AND THE TROUGH PUSHES THE MOISTURE SOUTH AND EAST OF
THE AREA...BUT GFS AND ECMWF SOLUTIONS ARE STARTING TO COME INTO
AGREEMENT FOR A DEVELOPING EASTERLY WAVE TO BRING ADDITIONAL
MOISTURE BACK INTO SOUTHERN CALIFORNIA BETWEEN THURSDAY AND
SATURDAY. WITH THIS BEING A NEW FEATURE...POPS HAVE BUMPED UP AT
THIS POINT FOR THE MOUNTAINS AND DESERT...HOWEVER...NO MENTION OF
SHOWERS OR THUNDERSTORMS EXISTS AT THIS TIME. WHILE A WARMING
TREND IS REFLECTED FOR LATE NEXT WEEK...WEDNESDAY COULD END UP
BEING THE WARMEST DAY IF THE ECMWF AND GFS SOLUTIONS PLAY OUT.
&&
.AVIATION...07/06Z.
NORTH OF POINT CONCEPTION...MODERATE CONFIDENCE THAT LIFR TO IFR
CONDITIONS WILL DEVELOP AT COASTAL SITES 04Z-11Z...WITH THE BEST
CHANCE OF LIFR TO IFR CONDITIONS BETWEEN 08Z AND 17Z. OTHERWISE AND
ELSEWHERE VFR CONDITIONS WILL PREVAIL
SOUTH OF POINT CONCEPTION...LOW TO MODERATE CONFIDENCE DUE TO
MOISTURE FROM HURRICANE NORBERT SPREADING NORTH. MID LEVEL CLOUD
COVER SHOULD HELP TO RETARD SURFACE CLOUD DEVELOPMENT. A TWENTY
PERCENT CHANCE OF IFR-MVFR CONDITIONS AT COASTAL SITES AND ADJACENT
VALLEYS 08Z-16Z. AFTER 15Z...THERE IS A SLIGHT CHANCE OF SHOWERS AT
LOS ANGELES COUNTY SITES... WITH A SLIGHT CHANCE OF THUNDERSTORMS
AFTER 18Z. OTHERWISE AND ELSEWHERE VFR CONDITIONS WILL PREVAIL.
KLAX...LOW TO MODERATE CONFIDENCE DUE TO MOISTURE FROM HURRICANE
NORBERT SPREADING NORTH. MID LEVEL CLOUD COVER SHOULD HELP TO
RETARD SURFACE CLOUD DEVELOPMENT. A TWENTY PERCENT CHANCE OF
IFR-MVFR CONDITIONS 08Z-16Z. DURING THE PERIOD 20Z-05Z...THERE IS A
SLIGHT CHANCE OF THUNDERSTORMS. OTHERWISE VFR CONDITIONS WILL
PREVAIL.
KBUR...LOW TO MODERATE CONFIDENCE DUE TO MOISTURE FROM HURRICANE
NORBERT SPREADING NORTH. MID LEVEL CLOUD COVER SHOULD HELP TO
RETARD SURFACE CLOUD DEVELOPMENT. A TEN PERCENT CHANCE OF MVFR
CONDITIONS 08Z-16Z. AFTER 18Z...THERE IS A SLIGHT CHANCE OF
THUNDERSTORMS. OTHERWISE VFR CONDITIONS WILL PREVAIL.
&&
.MARINE...07/300 AM.
HIGH CONFIDENCE IN A SMALL CRAFT ADVISORY THAT IS IN EFFECT FOR THE
OUTER WATERS THROUGH LATE MONDAY NIGHT FOR NORTHWEST WINDS GUSTING
TO 25 KNOTS. THE STRONGEST WINDS ARE EXPECTED BETWEEN POINT
CONCEPTION AND SAN NICOLAS ISLAND. FOR THE INNER WATERS...
CONDITIONS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS
THROUGH AT LEAST MID-WEEK.
HURRICANE NORBERT WILL AFFECT THE COASTAL WATERS THROUGH MONDAY WITH
LARGE SWELLS AND A SLIGHT CHANCE OF ISOLATED SHOWERS AND
THUNDERSTORMS. THE BEST CHANCE FOR CONVECTIVE WEATHER IS OFF THE LOS
ANGELES COUNTY COAST WITH CHANCES LESSENING TO THE NORTH. A MARINE
WEATHER STATEMENT HAS BEEN ISSUED TO ADDRESS THE POTENTIAL
CONVECTIVE WEATHER.
&&
.BEACHES...07/300 AM.
A BEACH HAZARD STATEMENT IS IN EFFECT THROUGH LATE MONDAY NIGHT FOR
VENTURA AND LOS ANGELES COUNTIES DUE TO HIGH SURF... HIGH RIP
CURRENT RISK... AND POSSIBLE MINOR COASTAL FLOODING NEAR EVENING
HIGH TIDE.
THE SOUTHERN HEMISPHERE SWELL WILL SLOWLY DIMINISH IN HEIGHT AND
PERIOD TODAY JUST AS THE EFFECTS OF HURRICANE NORBERT ARRIVE. THE
HURRICANE SWELL PERIOD WILL BE SHORTER... NEAR 11 SECONDS... BUT
WILL KEEP THE SURF ELEVATED FOR AN ADDITIONAL DAY. THE STRONG RIP
CURRENTS MAY CONTINUE THROUGH TUESDAY THOUGH SWELL AND SURF IS
SUBSIDING EARLIER.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY (SEE LAXNPWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
BEACH HAZARDS STATEMENT (SEE LAXCFWLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).
&&
$$
PUBLIC...HALL
AVIATION...KJ
BEACHES/MARINE....KJ
SYNOPSIS...HALL/SIRARD
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS CARIBOU ME
921 AM EDT SUN SEP 7 2014
.SYNOPSIS...
COOL AND DRY HIGH PRESSURE WILL BUILD INTO THE REGION THIS
AFTERNOON INTO MONDAY. THIS HIGH WILL LINGER INTO THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
920 AM UPDATE...NO SIGNIFICANT CHANGES WERE NEEDED WITH THIS
UPDATE. A BATCH OF CLOUDS IS SWINGING DOWN OUT OF EASTERN QUEBEC
THIS MORNING AND WILL CROSS THE NORTHERN HALF OF THE FORECAST AREA
LATE THIS MORNING THROUGH THE AFTERNOON. OTHERWISE, LOTS OF
SUNSHINE WILL BE THE RULE FOR TODAY. HAVE MADE ADJUSTMENTS TO SKY
COVER AND TEMPERATURES TO MATCH CURRENT SATELLITE AND SURFACE
OBSERVATION TRENDS. NO OTHER CHANGES WERE NEEDED.
PREVIOUS DISCUSSION...
MUCH COOLER AND DRIER THIS TERM.
06Z SURFACE ANALYSIS SHOWED A COLD FRONT HANGING OFF THE COAST
W/AN AREA OF SHOWERS MOVING UP ALONG THE COAST. THESE SHOWERS WERE
IN RESPONSE TO A WEAK SFC LOW THAT DEVELOPED ON THE FRONT. LATEST
SREF WAS HANDLING THE SHOWERS QUITE WELL W/THE SETUP. DECIDED TO
CARRY 60% POPS RIGHT ALONG THE COAST FOR EARLY THIS MORNING AND
THEN DROP THEM OFF AS THE LOW PULLS NE AND THE FRONT PULLS FURTHER
S. IR SATELLITE IMAGERY SHOWED CLOUDS ACROSS THE CWA W/CLEARING
TAKING PLACE ACROSS THE NORTHERN TIER. THE CLOUDS WILL PULL OUT OF
THE AREA BY LATE MORNING AS DRIER AIR CONTINUES TO POUR IN. A
SECOND FRONTAL BOUNDARY IS SHOWN BY THE NAM AND HRRR 3KM TO DROP S
ACROSS THE REGION THIS AFTERNOON. THE MODEL SOUNDINGS SUPPORT
MOISTURE IN THE 900-800MB LAYER ACROSS THE NORTHERN 1/2 OF THE CWA
WHILE DOWNEAST AND THE COAST WILL SEE SOME SCATTERED CLOUDINESS.
NW WINDS WILL PICK UP BEHIND THIS FRONT W/TEMPERATURES THIS
AFTERNOON ABOUT 10-15 DEGREES COLDER THAN THEY HAVE BEEN THE LAST
SEVERAL DAYS. WE ARE TALKING UPPER 60S TO AROUND 70.
HIGH PRES IS FORECAST TO SLIDE ACROSS THE REGION TONIGHT
W/CLEARING SKIES AND MUCH DRIER AIR. NW WINDS WILL DROP OFF
TONIGHT W/DEWPOINTS DROPPING INTO THE 30S BY EARLY MONDAY MORNING.
DECIDED TO CARRY PATCHY FOG W/THE COOLING AND WET GROUND FROM
SATURDAY`S RAIN. TEMPERATURES BY SUNRISE WILL HIT THE MID AND
UPPER 30S W/LOCATIONS SUCH AS THE ALLAGASH AND ST. JOHN VALLEY
SEEING LOWER 30S. THIS RAISES CONCERN FOR FROST BY EARLY MONDAY
MORNING MAINLY ACROSS THE NORTH AND WEST. COLLABORATED W/GYX AND
BTV ON THIS AND THINKING IS THAT THE FOG COULD OFFSET THE EXTENT
OF THE FROST W/A HEAVY DEW DEVELOPING. PLUS, WINDS COULD ACTUALLY
STAY UP A WHILE LONGER BEFORE DECOUPLING WHICH IN TURN LIMIT THE
DURATION OF THE FROST. THEREFORE, THE DECISION WAS NOT TO ISSUE A
FROST ADVISORY W/THIS PACKAGE BUT KEEP THE MENTION OF FROST IN
THE FORECAST. DAYCREW CAN ASSESS THIS FURTHER TODAY.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE AREA THROUGH THE
SHORT TERM PERIOD. A LOW PRESSURE SYSTEM WILL MOVE NORTH ALONG THE
ATLANTIC COAST...AT THIS TIME APPEARS WILL REMAIN SOUTH OF THE
GULF OF MAINE.
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 /WEDNESDAY THROUGH SATURDAY/...
A HIGH PRESSURE RIDGE WILL BE IN PLACE OVER THE AREA AT THE START
OF THE LONG TERM. A LOW TRACKING ACROSS THE GREAT LAKES WILL BRING
ITS ASSOCIATED FRONT INTO WRN MAINE THURS MRNG. THE GUIDANCE MOVES
THE FRONT INTO NEW BRUNSWICK FRI MRNG....UNSETTLED WEATHER WILL
CONTINUE AS THE UPPER LEVEL LOW ELONGATES ALONG THE US AND
CANADIAN BOARDER EXTENDING FRONT THE CENTRAL GREAT LAKES TO
ATLANTIC CANADA. THE UPPER LOW WILL REMAIN IN THE AREA THROUGH THE
END OF THE PERIOD. TROUGHS OF LOWER PRESSURE WILL ROTATE AROUND
THE LOW BRINGING PERIODS OF UNSETTLED WEATHER INTO NRN AND CENTRAL
MAINE THROUGH THE END OF THE PERIOD.
LOADED THE SUPERBLEND FOR THE EXTENDED PERIOD OF THE FORECAST.
&&
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: VFR W/TEMPO MVFR OR PERHAPS IFR BY EARLY MONDAY MORNING
FOR FOG DUE TO WET GROUND.
SHORT TERM: HIGH PRESSURE WILL DOMINATE THE WEATHER THROUGH THE
PERIOD. VFR CONDITIONS ALL SITE. LIGHT WINDS...COOLER TEMPS WILL
LIKELY ALLOW MORNING FOG PARTICULARLY AROUND WATER BODIES REDUCING
VISIBILITIES DURING THE EARLY MORNING HOURS.
&&
.MARINE...
NEAR TERM: WINDS HAVE DROPPED TO 10 KTS BUT SEAS STILL RUNNING
AROUND 5 FT. THINKING IS THAT SEAS WILL DROP BACK TODAY AS NW TAKE
HOLD AND HIGH PRES BUILDS E. WINDS WILL REMAIN 10 KT OR LESS.
SHORT TERM: WINDS AND SEAS BELOW SCA CRITERIA THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS/HEWITT
SHORT TERM...NORTON
LONG TERM...NORTON
AVIATION...HASTINGS/HEWITT/NORTON
MARINE...HASTINGS/HEWITT/NORTON
AREA FORECAST DISCUSSION
NWS CARIBOU ME
648 AM EDT SUN SEP 7 2014
.SYNOPSIS...
COOL AND DRY HIGH PRESSURE WILL BUILD INTO THE REGION THIS
AFTERNOON INTO MONDAY. THIS HIGH WILL LINGER INTO THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
645 AM UPDATE...ADJUSTED HRLY TEMPERATURES PER THE LATEST OBS
SHOWING SOME MID TO UPPER 30S ACROSS THE FAR NW AND LOW LYING
AREAS. CLOUDS WILL DEVELOP ACROSS THE NORTHERN TIER THIS AFTERNOON
AND MADE ADJUSTMENTS TO SHOW MOSTLY CLOUDY CONDITIONS IN THIS
AREA.
PREVIOUS DISCUSSION...
MUCH COOLER AND DRIER THIS TERM.
06Z SURFACE ANALYSIS SHOWED A COLD FRONT HANGING OFF THE COAST
W/AN AREA OF SHOWERS MOVING UP ALONG THE COAST. THESE SHOWERS WERE
IN RESPONSE TO A WEAK SFC LOW THAT DEVELOPED ON THE FRONT. LATEST
SREF WAS HANDLING THE SHOWERS QUITE WELL W/THE SETUP. DECIDED TO
CARRY 60% POPS RIGHT ALONG THE COAST FOR EARLY THIS MORNING AND
THEN DROP THEM OFF AS THE LOW PULLS NE AND THE FRONT PULLS FURTHER
S. IR SATELLITE IMAGERY SHOWED CLOUDS ACROSS THE CWA W/CLEARING
TAKING PLACE ACROSS THE NORTHERN TIER. THE CLOUDS WILL PULL OUT OF
THE AREA BY LATE MORNING AS DRIER AIR CONTINUES TO POUR IN. A
SECOND FRONTAL BOUNDARY IS SHOWN BY THE NAM AND HRRR 3KM TO DROP S
ACROSS THE REGION THIS AFTERNOON. THE MODEL SOUNDINGS SUPPORT
MOISTURE IN THE 900-800MB LAYER ACROSS THE NORTHERN 1/2 OF THE CWA
WHILE DOWNEAST AND THE COAST WILL SEE SOME SCATTERED CLOUDINESS.
NW WINDS WILL PICK UP BEHIND THIS FRONT W/TEMPERATURES THIS
AFTERNOON ABOUT 10-15 DEGREES COLDER THAN THEY HAVE BEEN THE LAST
SEVERAL DAYS. WE ARE TALKING UPPER 60S TO AROUND 70.
HIGH PRES IS FORECAST TO SLIDE ACROSS THE REGION TONIGHT
W/CLEARING SKIES AND MUCH DRIER AIR. NW WINDS WILL DROP OFF
TONIGHT W/DEWPOINTS DROPPING INTO THE 30S BY EARLY MONDAY MORNING.
DECIDED TO CARRY PATCHY FOG W/THE COOLING AND WET GROUND FROM
SATURDAY`S RAIN. TEMPERATURES BY SUNRISE WILL HIT THE MID AND
UPPER 30S W/LOCATIONS SUCH AS THE ALLAGASH AND ST. JOHN VALLEY
SEEING LOWER 30S. THIS RAISES CONCERN FOR FROST BY EARLY MONDAY
MORNING MAINLY ACROSS THE NORTH AND WEST. COLLABORATED W/GYX AND
BTV ON THIS AND THINKING IS THAT THE FOG COULD OFFSET THE EXTENT
OF THE FROST W/A HEAVY DEW DEVELOPING. PLUS, WINDS COULD ACTUALLY
STAY UP A WHILE LONGER BEFORE DECOUPLING WHICH IN TURN LIMIT THE
DURATION OF THE FROST. THEREFORE, THE DECISION WAS NOT TO ISSUE A
FROST ADVISORY W/THIS PACKAGE BUT KEEP THE MENTION OF FROST IN
THE FORECAST. DAYCREW CAN ASSESS THIS FURTHER TODAY.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE AREA THROUGH THE
SHORT TERM PERIOD. A LOW PRESSURE SYSTEM WILL MOVE NORTH ALONG THE
ATLANTIC COAST...AT THIS TIME APPEARS WILL REMAIN SOUTH OF THE
GULF OF MAINE.
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 /WEDNESDAY THROUGH SATURDAY/...
A HIGH PRESSURE RIDGE WILL BE IN PLACE OVER THE AREA AT THE START
OF THE LONG TERM. A LOW TRACKING ACROSS THE GREAT LAKES WILL BRING
ITS ASSOCIATED FRONT INTO WRN MAINE THURS MRNG. THE GUIDANCE MOVES
THE FRONT INTO NEW BRUNSWICK FRI MRNG....UNSETTLED WEATHER WILL
CONTINUE AS THE UPPER LEVEL LOW ELONGATES ALONG THE US AND
CANADIAN BOARDER EXTENDING FRONT THE CENTRAL GREAT LAKES TO
ATLANTIC CANADA. THE UPPER LOW WILL REMAIN IN THE AREA THROUGH THE
END OF THE PERIOD. TROUGHS OF LOWER PRESSURE WILL ROTATE AROUND
THE LOW BRINGING PERIODS OF UNSETTLED WEATHER INTO NRN AND CENTRAL
MAINE THROUGH THE END OF THE PERIOD.
LOADED THE SUPERBLEND FOR THE EXTENDED PERIOD OF THE FORECAST.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: VFR W/TEMPO MVFR OR PERHAPS IFR BY EARLY MONDAY MORNING
FOR FOG DUE TO WET GROUND.
SHORT TERM: HIGH PRESSURE WILL DOMINATE THE WEATHER THROUGH THE
PERIOD. VFR CONDITIONS ALL SITE. LIGHT WINDS...COOLER TEMPS WILL
LIKELY ALLOW MORNING FOG PARTICULARLY AROUND WATER BODIES REDUCING
VISIBILITIES DURING THE EARLY MORNING HOURS.
&&
.MARINE...
NEAR TERM: WINDS HAVE DROPPED TO 10 KTS BUT SEAS STILL RUNNING
AROUND 5 FT. THINKING IS THAT SEAS WILL DROP BACK TODAY AS NW TAKE
HOLD AND HIGH PRES BUILDS E. WINDS WILL REMAIN 10 KT OR LESS.
SHORT TERM: WINDS AND SEAS BELOW SCA CRITERIA THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...NORTON
LONG TERM...NORTON
AVIATION...HEWITT/NORTON
MARINE...HEWITT/NORTON
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1152 AM EDT SUN SEP 7 2014
.SYNOPSIS...
A COLD FRONT WILL STALL ALONG THE SOUTHEAST AND MID ATLANTIC
COASTS LATE THIS AFTERNOON AND REMAIN NEARLY STATIONARY THROUGH
TUESDAY NIGHT...WITH AN AREA OF LOW PRESSURE MOVING NORTHEAST
ALONG THE BOUNDARY MONDAY AFTERNOON THROUGH TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CDFNT HAS SLIPPED S OF THE FA AS OF LT MRNG...W/ NNE WNDS (GUSTY
AT TIMES AT THE CST) CONTG TO USER IN COOLER/DRIER AIR FM THE N
AS SFC HI PRES BUILDS TOWARDS NEW ENG. LOWERED POPS FOR THE REST
OF THE DAY...TO 30-40% FAR SE VA/NE NC...THEN TAPER OFF TO AOB 10%
ACRS FAR NNW AREAS. HI TEMPS RANGING THROUGH THE 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
GOING WITH A BLEND OF THE LATEST GFS/ECMWF MODELS FOR TNGT THRU
TUE NGT...RESULTING IN AN UNSETTLED RATHER WET PATTERN FOR THE
REGION. LO PRES DEVELOPING ALNG THE SE CST TNGT INTO MON...WILL
LIFT NE ALNG THE STALLED FRNTL BOUNDARY AND OFF THE VA/NC CST MON
AFTN THRU TUE NGT. THE COMBINATION OF INCREASING LO LVL MOISTURE
FM THE ATLC AND STRNG LIFT (ALNG/JUST N OF THE BOUNDARY AND
ASSOCIATED WITH THE LO)...WILL PRODUCE NUMEROUS SHOWERS OVR THE
AREA...ESPLY LATER TNGT INTO TUE AFTN. HIGHEST POPS/CHC FOR
HEAVIEST RAINFALL WILL BE OVR ERN/SERN CNTIES DURING THIS TIME.
POPS WILL DIMINISH FM W TO E TUE AFTN THRU TUE NGT...AS THE LO
MOVES FARTHER OUT TO SEA. ISLTD THUNDER POSSIBLE ESE AREAS.
LO TEMPS TNGT RANGING THRU THE 60S TO NEAR 70. HI TEMPS ON MON AND
TUE IN THE MID 70S TO ARND 80.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MEDIUM RANGE GUIDANCE IN FAIRLY GOOD AGREEMENT THROUGH THE
PERIOD. THE MAIN FEATURE WILL BE A COLD FRONT SET TO CROSS THE
LOCAL AREA LATE IN THE WEEK...BRINGING COOLER/DRIER CONDITIONS TO
THE REGION BY NEXT WEEKEND.
UPPER FLOW WILL BE CHARACTERIZED BY AN AMPLIFYING TROUGH OVER THE
CNTRL CONUS...DOWNSTREAM OF AN ANOMALOUS RIDGE OVER THE WRN
PACIFIC AND GULF OF ALASKA. OVER THE LOCAL AREA...A LEADING
SHORTWAVE WILL FLATTEN THE UPPER FLOW BRIEFLY WEDS BEFORE SWLY
FLOW INCREASES IN ADVANCE OF THE APPROACHING UPPER TROUGH THURS-
FRI. AN ASSOCIATED COLD FRONT AND PARENT LOW WILL REACH THE GREAT
LAKES/OH VALLEY LATE WEDS INTO WEDS NIGHT. MEANWHILE...WEDGE OVER
THE LOCAL AREA BREAKS DOWN IN ADVANCE OF THE FRONT WEDS. MID-LEVEL
HIGH PRESSURE OVER THE SE STATES WILL RIDGE NEWD INTO THE MID-
ATLANTIC AS SFC HIGH BREAKS DOWN. SUBSIDENCE VISIBLE IN MODEL
SOUNDINGS COMBINED WITH LITTLE INSTABILITY AND THETA-E ADVECTION
WILL LIKELY INHIBIT PRECIP WEDS. WINDS VEER TO THE SOUTH WEDS
NIGHT AS SWLY FLOW ALOFT INCREASES. PRE-FRONTAL TROUGH FORECAST TO
DEVELOP OVER THE LOCAL AREA THURS...WHICH COMBINED WITH THETA-E
ADVECTION/INSTABILITY MAY PROVIDE THE FOCUS FOR AFTERNOON SHOWERS
AND THUNDERSTORMS. HOWEVER...LACK OF APPRECIABLE FORCING OUTSIDE
OF SMALL AMPLITUDE WAVES IN SWLY FLOW WILL LIKELY RESULT IN ONLY
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS. BEST COVERAGE
ANTICIPATED OVER THE PIEDMONT INTO CNTRL VA AND ALONG THE COAST TO
ACCOUNT FOR SEABREEZE BOUNDARIES. MODELS IN GOOD AGREEMENT WITH
DROPPING THE COLD FRONT INTO THE LOCAL AREA LATE THURS NIGHT INTO
FRI. THE UPPER WAVE DE-AMPLIFIES...WITH THE BEST DYNAMICS REMAINING
NORTH OF THE LOCAL AREA. DESPITE LACK OF DYNAMICS...WILL INCREASE
POPS TO CHANCE AS A WARM/MOIST AND MARGINALLY UNSTABLE AIR MASS IS
ANTICIPATED. OF COURSE...TIMING OF THE FRONT WILL IMPACT WHERE THE
BEST COVERAGE WILL BE ON FRIDAY AND HOW WARM TEMPS GET. EXPECT THE
FRONT TO CLEAR THE LOCAL AREA FRI NIGHT AS COOL CANADIAN HIGH
PRESSURE BUILDS IN FROM THE WEST. BEST CAA ARRIVES FRI NIGHT-SAT
AS HIGH PRESSURE REMAINS OVER THE OH VALLEY. THE RESULT WILL BE
PARTLY CLOUDY SKIES SAT WITH HIGHS IN THE UPPER 70S. WILL HOLD
ONTO SLIGHT CHANCE-CHANCE POPS ACROSS THE SE TO ACCOUNT FOR SLOWER
ECMWF AND PROXIMITY TO FRONT/MOISTURE.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
AS OF 12Z...COLD FRONT WILL CONTINUE TO SLIDE SOUTH ACRS SOUTHERN
TERMINALS THROUGH MID-MORNING.
MVFR CIGS AT ALL TERMINALS THIS MORNING. EXPECT RETURN TO VFR BY
MIDDAY AT RIC BUT ELSEWHERE AT SBY AND AT COASTAL TERMINALS, KEPT
LOW CLOUDS IN PLACE FOR MUCH OF THE DAY WITH SOME VCSH WORDING FOR
THE AFTN. NE WINDS IN THE WAKE OF THE FRONT WILL INCREASE TO 10
TO 15 KNOTS AT ORF AND ECG AS THE PRESSURE GRADIENT TIGHTENS IN
THAT AREA. EXPECT SHOWERS TO BECOME MORE WIDESPREAD AFTER 22Z,
WITH BRIEF VSBY RESTRICTIONS POSSIBLE AFTER THIS TIME THROUGH THE
EVENING AT ECG/PHF/ORF.
OUTLOOK...FRONT BECOMES STALLED TO OUR SE, AND UNSETTLED
CONDITIONS CONTINUE THROUGH TUESDAY. MVFR CIGS WL PERSIST THROUGH
THE NIGHT AND SOME BRIEF PERIODS OF IFR PSBL OVERNIGHT...ESPECIALLY
AT ORF AND ECG. SHOWERS WILL RE-DEVELOP MONDAY AFTN THROUGH EARLY
TUESDAY, WITH ANOTHER EXTENDED PERIOD OF SUB-VFR CONDITIONS
LIKELY AT COASTAL TERMINALS. DRIER WEATHER AND A RETURN TO VFR
CONDS ARE FORECAST LATE TUESDAY THROUGH FRIDAY.
&&
.MARINE...
LATEST SFC ANALYSIS SFC COLD FRONT MOVING SOUTH ACROSS THE WATERS
THIS MORNING, WITH SOME SCT SHRAS ACROSS NORTHERN WATERS ALONG
PRE-FRONTAL TROUGH. FLOW IS E-NE ACROSS NORTHERN WATERS, WITH SW
FLOW FARTHER SOUTH ALONG CENTRAL/SOUTHERN COASTAL WATERS AND THE
LOWER CHES BAY. FRONT WILL DROP SOUTH ACROSS THE WATERS OVER THE
NEXT FEW HOURS WITH A BRIEF SURGE EXPECTED LATER THIS MORNING AS THE
BETTER CAA ARRIVES. LOOKING AT OBS IN THE UPPER CHES BAY, NOTING
GUSTS TO 18-22 KT OVER UPPER BAY, GENERALLY IN LINE WITH HRRR
DEPICTION. HRRR AND DOWNSCALE NAM DEPICTING A SHORT LIVED N-NE SURGE
WITH NE WINDS GUSTING TO MARGINAL/LOW END SCA IN THE BAY.
ACCORDINGLY, HV HOISTED A RELATIVELY SHORT DURATION SCA THROUGH
NOON.
FRONT WILL BECOME STALLED ALONG THE COAST LATE TONIGHT AND MONDAY
AS HIGH PRESSURE BUILDS OVER NEW ENGLAND. E-NELY FLOW CONTINUES
THROUGH THE PERIOD WITH HIGH PRESSURE REMAINING RIDGED OVER THE
WATERS THRU WEDNESDAY. MEANWHILE...LOW PRESSURE WILL DEVELOP ALONG
THE FRONT AND LIFT ALONG THE SE COAST AND OFF THE MID-ATLANTIC COAST
MON-WED. THIS WILL SERVE TO STRENGTHEN THE PRESSURE GRADIENT OVER
THE NRN WATERS...RESULTING IN NELY WINDS OF 20-25 KT OVER THE NRN
COASTAL WATERS DEVELOPING LATE TONIGHT INTO MON. SEAS WILL
RESPOND...BUILDING TO 4-6 FT NORTH OF CAPE CHARLES LIGHT. HV GONE
AHEAD WITH AN SCA OVER ATLANTIC COASTAL WATERS NORTH OF PARRAMORE
ISLAND FROM 6A MON-6A TUES. WINDS/SEAS REMAIN ELEVATED MON/MON NGT
BEFORE THE PRESSURE GRADIENT RELAXES. WEDGE BEGINS TO BREAK DOWN
WEDS AS A COLD FRONT APPROACHES FROM THE WEST. FLOW BECOMES SLY WED
NIGHT INTO THURS AND SWLY THURS AND FRI IN ADVANCE OF THE NEXT COLD
FRONT, WHICH IS FORECAST TO CROSS THE WATERS THURS NIGHT INTO FRI.
&&
.TIDES/COASTAL FLOODING...
DEVELOPING NE FLOW 15-20KT WILL DEVELOP LATER TODAY AND PERSIST
THROUGH TUESDAY NIGHT, AND WILL RESULT IN BUILDING TIDAL
ANOMALIES APPROACHING 1 TO 1.5 FT ABOVE NORMAL BY LATER MONDAY
THROUGH EARLY TUESDAY. NUISANCE TO LOW END MINOR TIDAL FLOODING
WILL BE POSSIBLE DURING THE MONDAY EVENING AND TUESDAY MORNING
HIGH TIDE CYCLES.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
ANZ650-652.
SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR
ANZ630>632.
&&
$$
SYNOPSIS...ALB/TMG
NEAR TERM...ALB/TMG
SHORT TERM...ALB/TMG
LONG TERM...SAM
AVIATION...MAM
MARINE...MAM
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1122 AM EDT SUN SEP 7 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE AREA INTO THIS AFTERNOON. THE
FRONT WILL STALL ALONG THE SOUTHEAST AND MID ATLANTIC COASTS
LATER THIS AFTERNOON THROUGH TUESDAY NIGHT...WITH AN AREA OF LOW
PRESSURE MOVING NORTHEAST ALONG THE BOUNDARY MONDAY AFTERNOON
THROUGH TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A COLD FRONT WILL DROP ACRS THE REGION THIS MORNG INTO THIS
AFTN...THEN STALL ALONG THE SE AND MID ATLC CSTS LATER THIS AFTN
THRU TUE NGT...AS HI PRES BLDS FM THE OH VLY/LWR GRT LKS ENE INTO
THE CANADIAN MARITIMES. DRIER AIR WILL TRY TO NUDGE INTO NNW
PORTIONS OF THE AREA THIS AFTN INTO THIS EVENG...RESULTING IN THE
HIGHEST POPS (50-70%) SHIFTING INTO SRN/SE CNTIES. GENERALLY MSTLY
CLDY WITH POPS 15-25%. HI TEMPS WILL RANGE FM THE UPR 70S N TO
THE LWR 80S SE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
GOING WITH A BLEND OF THE LATEST GFS/ECMWF MODELS FOR TNGT THRU
TUE NGT...RESULTING IN AN UNSETTLED RATHER WET PATTERN FOR THE
REGION. LO PRES DEVELOPING ALNG THE SE CST TNGT INTO MON...WILL
LIFT NE ALNG THE STALLED FRNTL BOUNDARY AND OFF THE VA/NC CST MON
AFTN THRU TUE NGT. THE COMBINATION OF INCREASING LO LVL MOISTURE
FM THE ATLC AND STRNG LIFT (ALNG/JUST N OF THE BOUNDARY AND
ASSOCIATED WITH THE LO)...WILL PRODUCE NUMEROUS SHOWERS OVR THE
AREA...ESPLY LATER TNGT INTO TUE AFTN. HIGHEST POPS/CHC FOR
HEAVIEST RAINFALL WILL BE OVR ERN/SERN CNTIES DURING THIS TIME.
POPS WILL DIMINISH FM W TO E TUE AFTN THRU TUE NGT...AS THE LO
MOVES FARTHER OUT TO SEA. ISLTD THUNDER POSSIBLE ESE AREAS.
LO TEMPS TNGT RANGING THRU THE 60S TO NEAR 70. HI TEMPS ON MON AND
TUE IN THE MID 70S TO ARND 80.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MEDIUM RANGE GUIDANCE IN FAIRLY GOOD AGREEMENT THROUGH THE
PERIOD. THE MAIN FEATURE WILL BE A COLD FRONT SET TO CROSS THE
LOCAL AREA LATE IN THE WEEK...BRINGING COOLER/DRIER CONDITIONS TO
THE REGION BY NEXT WEEKEND.
UPPER FLOW WILL BE CHARACTERIZED BY AN AMPLIFYING TROUGH OVER THE
CNTRL CONUS...DOWNSTREAM OF AN ANOMALOUS RIDGE OVER THE WRN
PACIFIC AND GULF OF ALASKA. OVER THE LOCAL AREA...A LEADING
SHORTWAVE WILL FLATTEN THE UPPER FLOW BRIEFLY WEDS BEFORE SWLY
FLOW INCREASES IN ADVANCE OF THE APPROACHING UPPER TROUGH THURS-
FRI. AN ASSOCIATED COLD FRONT AND PARENT LOW WILL REACH THE GREAT
LAKES/OH VALLEY LATE WEDS INTO WEDS NIGHT. MEANWHILE...WEDGE OVER
THE LOCAL AREA BREAKS DOWN IN ADVANCE OF THE FRONT WEDS. MID-LEVEL
HIGH PRESSURE OVER THE SE STATES WILL RIDGE NEWD INTO THE MID-
ATLANTIC AS SFC HIGH BREAKS DOWN. SUBSIDENCE VISIBLE IN MODEL
SOUNDINGS COMBINED WITH LITTLE INSTABILITY AND THETA-E ADVECTION
WILL LIKELY INHIBIT PRECIP WEDS. WINDS VEER TO THE SOUTH WEDS
NIGHT AS SWLY FLOW ALOFT INCREASES. PRE-FRONTAL TROUGH FORECAST TO
DEVELOP OVER THE LOCAL AREA THURS...WHICH COMBINED WITH THETA-E
ADVECTION/INSTABILITY MAY PROVIDE THE FOCUS FOR AFTERNOON SHOWERS
AND THUNDERSTORMS. HOWEVER...LACK OF APPRECIABLE FORCING OUTSIDE
OF SMALL AMPLITUDE WAVES IN SWLY FLOW WILL LIKELY RESULT IN ONLY
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS. BEST COVERAGE
ANTICIPATED OVER THE PIEDMONT INTO CNTRL VA AND ALONG THE COAST TO
ACCOUNT FOR SEABREEZE BOUNDARIES. MODELS IN GOOD AGREEMENT WITH
DROPPING THE COLD FRONT INTO THE LOCAL AREA LATE THURS NIGHT INTO
FRI. THE UPPER WAVE DE-AMPLIFIES...WITH THE BEST DYNAMICS REMAINING
NORTH OF THE LOCAL AREA. DESPITE LACK OF DYNAMICS...WILL INCREASE
POPS TO CHANCE AS A WARM/MOIST AND MARGINALLY UNSTABLE AIR MASS IS
ANTICIPATED. OF COURSE...TIMING OF THE FRONT WILL IMPACT WHERE THE
BEST COVERAGE WILL BE ON FRIDAY AND HOW WARM TEMPS GET. EXPECT THE
FRONT TO CLEAR THE LOCAL AREA FRI NIGHT AS COOL CANADIAN HIGH
PRESSURE BUILDS IN FROM THE WEST. BEST CAA ARRIVES FRI NIGHT-SAT
AS HIGH PRESSURE REMAINS OVER THE OH VALLEY. THE RESULT WILL BE
PARTLY CLOUDY SKIES SAT WITH HIGHS IN THE UPPER 70S. WILL HOLD
ONTO SLIGHT CHANCE-CHANCE POPS ACROSS THE SE TO ACCOUNT FOR SLOWER
ECMWF AND PROXIMITY TO FRONT/MOISTURE.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
AS OF 12Z...COLD FRONT WILL CONTINUE TO SLIDE SOUTH ACRS SOUTHERN
TERMINALS THROUGH MID-MORNING.
MVFR CIGS AT ALL TERMINALS THIS MORNING. EXPECT RETURN TO VFR BY
MIDDAY AT RIC BUT ELSEWHERE AT SBY AND AT COASTAL TERMINALS, KEPT
LOW CLOUDS IN PLACE FOR MUCH OF THE DAY WITH SOME VCSH WORDING FOR
THE AFTN. NE WINDS IN THE WAKE OF THE FRONT WILL INCREASE TO 10
TO 15 KNOTS AT ORF AND ECG AS THE PRESSURE GRADIENT TIGHTENS IN
THAT AREA. EXPECT SHOWERS TO BECOME MORE WIDESPREAD AFTER 22Z,
WITH BRIEF VSBY RESTRICTIONS POSSIBLE AFTER THIS TIME THROUGH THE
EVENING AT ECG/PHF/ORF.
OUTLOOK...FRONT BECOMES STALLED TO OUR SE, AND UNSETTLED
CONDITIONS CONTINUE THROUGH TUESDAY. MVFR CIGS WL PERSIST THROUGH
THE NIGHT AND SOME BRIEF PERIODS OF IFR PSBL OVERNIGHT...ESPECIALLY
AT ORF AND ECG. SHOWERS WILL RE-DEVELOP MONDAY AFTN THROUGH EARLY
TUESDAY, WITH ANOTHER EXTENDED PERIOD OF SUB-VFR CONDITIONS
LIKELY AT COASTAL TERMINALS. DRIER WEATHER AND A RETURN TO VFR
CONDS ARE FORECAST LATE TUESDAY THROUGH FRIDAY.
&&
.MARINE...
LATEST SFC ANALYSIS SFC COLD FRONT MOVING SOUTH ACROSS THE WATERS
THIS MORNING, WITH SOME SCT SHRAS ACROSS NORTHERN WATERS ALONG
PRE-FRONTAL TROUGH. FLOW IS E-NE ACROSS NORTHERN WATERS, WITH SW
FLOW FARTHER SOUTH ALONG CENTRAL/SOUTHERN COASTAL WATERS AND THE
LOWER CHES BAY. FRONT WILL DROP SOUTH ACROSS THE WATERS OVER THE
NEXT FEW HOURS WITH A BRIEF SURGE EXPECTED LATER THIS MORNING AS THE
BETTER CAA ARRIVES. LOOKING AT OBS IN THE UPPER CHES BAY, NOTING
GUSTS TO 18-22 KT OVER UPPER BAY, GENERALLY IN LINE WITH HRRR
DEPICTION. HRRR AND DOWNSCALE NAM DEPICTING A SHORT LIVED N-NE SURGE
WITH NE WINDS GUSTING TO MARGINAL/LOW END SCA IN THE BAY.
ACCORDINGLY, HV HOISTED A RELATIVELY SHORT DURATION SCA THROUGH
NOON.
FRONT WILL BECOME STALLED ALONG THE COAST LATE TONIGHT AND MONDAY
AS HIGH PRESSURE BUILDS OVER NEW ENGLAND. E-NELY FLOW CONTINUES
THROUGH THE PERIOD WITH HIGH PRESSURE REMAINING RIDGED OVER THE
WATERS THRU WEDNESDAY. MEANWHILE...LOW PRESSURE WILL DEVELOP ALONG
THE FRONT AND LIFT ALONG THE SE COAST AND OFF THE MID-ATLANTIC COAST
MON-WED. THIS WILL SERVE TO STRENGTHEN THE PRESSURE GRADIENT OVER
THE NRN WATERS...RESULTING IN NELY WINDS OF 20-25 KT OVER THE NRN
COASTAL WATERS DEVELOPING LATE TONIGHT INTO MON. SEAS WILL
RESPOND...BUILDING TO 4-6 FT NORTH OF CAPE CHARLES LIGHT. HV GONE
AHEAD WITH AN SCA OVER ATLANTIC COASTAL WATERS NORTH OF PARRAMORE
ISLAND FROM 6A MON-6A TUES. WINDS/SEAS REMAIN ELEVATED MON/MON NGT
BEFORE THE PRESSURE GRADIENT RELAXES. WEDGE BEGINS TO BREAK DOWN
WEDS AS A COLD FRONT APPROACHES FROM THE WEST. FLOW BECOMES SLY WED
NIGHT INTO THURS AND SWLY THURS AND FRI IN ADVANCE OF THE NEXT COLD
FRONT, WHICH IS FORECAST TO CROSS THE WATERS THURS NIGHT INTO FRI.
&&
.TIDES/COASTAL FLOODING...
DEVELOPING NE FLOW 15-20KT WILL DEVELOP LATER TODAY AND PERSIST
THROUGH TUESDAY NIGHT, AND WILL RESULT IN BUILDING TIDAL
ANOMALIES APPROACHING 1 TO 1.5 FT ABOVE NORMAL BY LATER MONDAY
THROUGH EARLY TUESDAY. NUISANCE TO LOW END MINOR TIDAL FLOODING
WILL BE POSSIBLE DURING THE MONDAY EVENING AND TUESDAY MORNING
HIGH TIDE CYCLES.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
ANZ650-652.
SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR
ANZ630>632.
&&
$$
SYNOPSIS...ALB/TMG
NEAR TERM...ALB/TMG
SHORT TERM...ALB/TMG
LONG TERM...SAM
AVIATION...MAM
MARINE...MAM
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
741 AM EDT SUN SEP 7 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE AREA INTO THIS AFTERNOON. THE
FRONT WILL STALL ALONG THE SOUTHEAST AND MID ATLANTIC COASTS
LATER THIS AFTERNOON THROUGH TUESDAY NIGHT...WITH AN AREA OF LOW
PRESSURE MOVING NORTHEAST ALONG THE BOUNDARY MONDAY AFTERNOON
THROUGH TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A COLD FRONT WILL DROP ACRS THE REGION THIS MORNG INTO THIS
AFTN...THEN STALL ALONG THE SE AND MID ATLC CSTS LATER THIS AFTN
THRU TUE NGT...AS HI PRES BLDS FM THE OH VLY/LWR GRT LKS ENE INTO
THE CANADIAN MARITIMES. DRIER AIR WILL TRY TO NUDGE INTO NNW
PORTIONS OF THE AREA THIS AFTN INTO THIS EVENG...RESULTING IN THE
HIGHEST POPS (50-70%) SHIFTING INTO SRN/SE CNTIES. GENERALLY MSTLY
CLDY WITH POPS 15-25%. HI TEMPS WILL RANGE FM THE UPR 70S N TO
THE LWR 80S SE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
GOING WITH A BLEND OF THE LATEST GFS/ECMWF MODELS FOR TNGT THRU
TUE NGT...RESULTING IN AN UNSETTLED RATHER WET PATTERN FOR THE
REGION. LO PRES DEVELOPING ALNG THE SE CST TNGT INTO MON...WILL
LIFT NE ALNG THE STALLED FRNTL BOUNDARY AND OFF THE VA/NC CST MON
AFTN THRU TUE NGT. THE COMBINATION OF INCREASING LO LVL MOISTURE
FM THE ATLC AND STRNG LIFT (ALNG/JUST N OF THE BOUNDARY AND
ASSOCIATED WITH THE LO)...WILL PRODUCE NUMEROUS SHOWERS OVR THE
AREA...ESPLY LATER TNGT INTO TUE AFTN. HIGHEST POPS/CHC FOR
HEAVIEST RAINFALL WILL BE OVR ERN/SERN CNTIES DURING THIS TIME.
POPS WILL DIMINISH FM W TO E TUE AFTN THRU TUE NGT...AS THE LO
MOVES FARTHER OUT TO SEA. ISLTD THUNDER POSSIBLE ESE AREAS.
LO TEMPS TNGT RANGING THRU THE 60S TO NEAR 70. HI TEMPS ON MON AND
TUE IN THE MID 70S TO ARND 80.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MEDIUM RANGE GUIDANCE IN FAIRLY GOOD AGREEMENT THROUGH THE
PERIOD. THE MAIN FEATURE WILL BE A COLD FRONT SET TO CROSS THE
LOCAL AREA LATE IN THE WEEK...BRINGING COOLER/DRIER CONDITIONS TO
THE REGION BY NEXT WEEKEND.
UPPER FLOW WILL BE CHARACTERIZED BY AN AMPLIFYING TROUGH OVER THE
CNTRL CONUS...DOWNSTREAM OF AN ANOMALOUS RIDGE OVER THE WRN
PACIFIC AND GULF OF ALASKA. OVER THE LOCAL AREA...A LEADING
SHORTWAVE WILL FLATTEN THE UPPER FLOW BRIEFLY WEDS BEFORE SWLY
FLOW INCREASES IN ADVANCE OF THE APPROACHING UPPER TROUGH THURS-
FRI. AN ASSOCIATED COLD FRONT AND PARENT LOW WILL REACH THE GREAT
LAKES/OH VALLEY LATE WEDS INTO WEDS NIGHT. MEANWHILE...WEDGE OVER
THE LOCAL AREA BREAKS DOWN IN ADVANCE OF THE FRONT WEDS. MID-LEVEL
HIGH PRESSURE OVER THE SE STATES WILL RIDGE NEWD INTO THE MID-
ATLANTIC AS SFC HIGH BREAKS DOWN. SUBSIDENCE VISIBLE IN MODEL
SOUNDINGS COMBINED WITH LITTLE INSTABILITY AND THETA-E ADVECTION
WILL LIKELY INHIBIT PRECIP WEDS. WINDS VEER TO THE SOUTH WEDS
NIGHT AS SWLY FLOW ALOFT INCREASES. PRE-FRONTAL TROUGH FORECAST TO
DEVELOP OVER THE LOCAL AREA THURS...WHICH COMBINED WITH THETA-E
ADVECTION/INSTABILITY MAY PROVIDE THE FOCUS FOR AFTERNOON SHOWERS
AND THUNDERSTORMS. HOWEVER...LACK OF APPRECIABLE FORCING OUTSIDE
OF SMALL AMPLITUDE WAVES IN SWLY FLOW WILL LIKELY RESULT IN ONLY
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS. BEST COVERAGE
ANTICIPATED OVER THE PIEDMONT INTO CNTRL VA AND ALONG THE COAST TO
ACCOUNT FOR SEABREEZE BOUNDARIES. MODELS IN GOOD AGREEMENT WITH
DROPPING THE COLD FRONT INTO THE LOCAL AREA LATE THURS NIGHT INTO
FRI. THE UPPER WAVE DE-AMPLIFIES...WITH THE BEST DYNAMICS REMAINING
NORTH OF THE LOCAL AREA. DESPITE LACK OF DYNAMICS...WILL INCREASE
POPS TO CHANCE AS A WARM/MOIST AND MARGINALLY UNSTABLE AIR MASS IS
ANTICIPATED. OF COURSE...TIMING OF THE FRONT WILL IMPACT WHERE THE
BEST COVERAGE WILL BE ON FRIDAY AND HOW WARM TEMPS GET. EXPECT THE
FRONT TO CLEAR THE LOCAL AREA FRI NIGHT AS COOL CANADIAN HIGH
PRESSURE BUILDS IN FROM THE WEST. BEST CAA ARRIVES FRI NIGHT-SAT
AS HIGH PRESSURE REMAINS OVER THE OH VALLEY. THE RESULT WILL BE
PARTLY CLOUDY SKIES SAT WITH HIGHS IN THE UPPER 70S. WILL HOLD
ONTO SLIGHT CHANCE-CHANCE POPS ACROSS THE SE TO ACCOUNT FOR SLOWER
ECMWF AND PROXIMITY TO FRONT/MOISTURE.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 12Z...COLD FRONT WILL CONTINUE TO SLIDE SOUTH ACRS SOUTHERN
TERMINALS THROUGH MID-MORNING.
MVFR CIGS AT ALL TERMINALS THIS MORNING. EXPECT RETURN TO VFR BY
MIDDAY AT RIC BUT ELSEWHERE AT SBY AND AT COASTAL TERMINALS, KEPT
LOW CLOUDS IN PLACE FOR MUCH OF THE DAY WITH SOME VCSH WORDING FOR
THE AFTN. NE WINDS IN THE WAKE OF THE FRONT WILL INCREASE TO 10
TO 15 KNOTS AT ORF AND ECG AS THE PRESSURE GRADIENT TIGHTENS IN
THAT AREA. EXPECT SHOWERS TO BECOME MORE WIDESPREAD AFTER 22Z,
WITH BRIEF VSBY RESTRICTIONS POSSIBLE AFTER THIS TIME THROUGH THE
EVENING AT ECG/PHF/ORF.
OUTLOOK...FRONT BECOMES STALLED TO OUR SE, AND UNSETTLED
CONDITIONS CONTINUE THROUGH TUESDAY. MVFR CIGS WL PERSIST THROUGH
THE NIGHT AND SOME BRIEF PERIODS OF IFR PSBL OVERNIGHT...ESPECIALLY
AT ORF AND ECG. SHOWERS WILL RE-DEVELOP MONDAY AFTN THROUGH EARLY
TUESDAY, WITH ANOTHER EXTENDED PERIOD OF SUB-VFR CONDITIONS
LIKELY AT COASTAL TERMINALS. DRIER WEATHER AND A RETURN TO VFR
CONDS ARE FORECAST LATE TUESDAY THROUGH FRIDAY.
&&
.MARINE...
LATEST SFC ANALYSIS SFC COLD FRONT MOVING SOUTH ACROSS THE WATERS
THIS MORNING, WITH SOME SCT SHRAS ACROSS NORTHERN WATERS ALONG
PRE-FRONTAL TROUGH. FLOW IS E-NE ACROSS NORTHERN WATERS, WITH SW
FLOW FARTHER SOUTH ALONG CENTRAL/SOUTHERN COASTAL WATERS AND THE
LOWER CHES BAY. FRONT WILL DROP SOUTH ACROSS THE WATERS OVER THE
NEXT FEW HOURS WITH A BRIEF SURGE EXPECTED LATER THIS MORNING AS THE
BETTER CAA ARRIVES. LOOKING AT OBS IN THE UPPER CHES BAY, NOTING
GUSTS TO 18-22 KT OVER UPPER BAY, GENERALLY IN LINE WITH HRRR
DEPICTION. HRRR AND DOWNSCALE NAM DEPICTING A SHORT LIVED N-NE SURGE
WITH NE WINDS GUSTING TO MARGINAL/LOW END SCA IN THE BAY.
ACCORDINGLY, HV HOISTED A RELATIVELY SHORT DURATION SCA THROUGH
NOON.
FRONT WILL BECOME STALLED ALONG THE COAST LATE TONIGHT AND MONDAY
AS HIGH PRESSURE BUILDS OVER NEW ENGLAND. E-NELY FLOW CONTINUES
THROUGH THE PERIOD WITH HIGH PRESSURE REMAINING RIDGED OVER THE
WATERS THRU WEDNESDAY. MEANWHILE...LOW PRESSURE WILL DEVELOP ALONG
THE FRONT AND LIFT ALONG THE SE COAST AND OFF THE MID-ATLANTIC COAST
MON-WED. THIS WILL SERVE TO STRENGTHEN THE PRESSURE GRADIENT OVER
THE NRN WATERS...RESULTING IN NELY WINDS OF 20-25 KT OVER THE NRN
COASTAL WATERS DEVELOPING LATE TONIGHT INTO MON. SEAS WILL
RESPOND...BUILDING TO 4-6 FT NORTH OF CAPE CHARLES LIGHT. HV GONE
AHEAD WITH AN SCA OVER ATLANTIC COASTAL WATERS NORTH OF PARRAMORE
ISLAND FROM 6A MON-6A TUES. WINDS/SEAS REMAIN ELEVATED MON/MON NGT
BEFORE THE PRESSURE GRADIENT RELAXES. WEDGE BEGINS TO BREAK DOWN
WEDS AS A COLD FRONT APPROACHES FROM THE WEST. FLOW BECOMES SLY WED
NIGHT INTO THURS AND SWLY THURS AND FRI IN ADVANCE OF THE NEXT COLD
FRONT, WHICH IS FORECAST TO CROSS THE WATERS THURS NIGHT INTO FRI.
&&
.TIDES/COASTAL FLOODING...
DEVELOPING NE FLOW 15-20KT WILL DEVELOP LATER TODAY AND PERSIST
THROUGH TUESDAY NIGHT, AND WILL RESULT IN BUILDING TIDAL
ANOMALIES APPROACHING 1 TO 1.5 FT ABOVE NORMAL BY LATER MONDAY
THROUGH EARLY TUESDAY. NUISANCE TO LOW END MINOR TIDAL FLOODING
WILL BE POSSIBLE DURING THE MONDAY EVENING AND TUESDAY MORNING
HIGH TIDE CYCLES.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
ANZ650-652.
SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR ANZ630>632.
&&
$$
SYNOPSIS...TMG
NEAR TERM...TMG
SHORT TERM...ALB/TMG
LONG TERM...SAM
AVIATION...MAM
MARINE...MAM
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
723 AM EDT SUN SEP 7 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM EDT SUN SEP 7 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR LKS BTWN AN UPR RDG OVER WRN NAMERICA AND A TROF IN THE E. A
SHRTWV EMBEDDED IN THIS WNW FLOW IS LOCATED NEAR JAMES BAY EARLY
THIS MRNG. A RIBBON OF MSTR/CLD COVER/SOME SHOWERS IS NOTED ALONG
ITS ATTENDANT COLD FNT STRECHING SWWD TOWARD NRN LK SUP AND A WEAK
LO PRES CENTER RUNNING EWD ALONG THE MN/ONTARIO BORDER. THE THICKER
CLDS AND SHOWERS JUST N OF LK SUP APPEAR TO FORCED BY AREA OF H85-5
QVECTOR CNVGC DEPICTED BY THE SHORT TERM MODELS. UPR MI IS DOMINATED
BY A LLVL W FLOW BTWN THE COLD FNT/SFC LO AND HI PRES MOVING INTO
THE MID MS RIVER VALLEY. THE UPSTREAM 00Z INL RAOB IS FAIRLY DRY
WITH 00Z H85/H7 DEWPT DEPRESSIONS RUNNING AT 7C/8C.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON HOW FAR S THE
AREA OF CLDS/SHOWERS JUST N OF LK SUP WL MOVE AND TEMPS FOR THIS
AFTN/TNGT.
TODAY...AS THE SHRTWV NEAR JAMES BAY MOVES ESEWD THRU QUEBEC
TODAY...ITS ATTENDANT COLD FNT IS PROGGED TO SHIFT S THRU NRN LK SUP
BEFORE STALLING NEAR THE KEWEENAW. SINCE THE AREA OF QVECTOR CNVGC
FORCING THE THICKER CLDS/SHOWERS NOW IN ONTARIO IS FCST TO SHIFT
ESEWD OVER NRN LK SUP AND N OF THE LAND CWA WITH THE DRY H85-7 W
FLOW DOMINATING...ALL THE SHORT TERM MODELS SHOW THE SHOWERS MOVING
NO FARTHER S THAN THE CNDN BORDER IN LK SUP BEFORE EXITING TO THE E
BY 18Z. ALTHOUGH SCT-BKN MID CLDS MAY BRUSH NRN UPR MI MAINLY THIS
MRNG...THERE SHOULD BE NO OTHER IMPACT. THE HI PRES NOW IN THE MID
MS RIVER VALLEY IS FCST TO SHIFT TO THE SE GREAT LKS BY 0Z MON. THE
WSW H925-85 FLOW THIS AFTN ARND THIS FEATURE IS FCST TO LIFT H85
TEMPS UP TO ARND 12C OVER THE CWA. THE FCST DEEP MIXED LYR/NEARLY
ADIABATIC SFC-H75 LAPSE RATES SHOWN ON FCST SDNGS WARRANTS HI TEMPS
TOWARD THE HI END OF GUIDANCE AND NEAR 80 OVER THE SCENTRAL AWAY FM
LK MODERATION. WEAKER GRADIENT NEAR LK SUP ASSOCIATED WITH LINGERING
LO PRES TROF SHOULD ALLOW FOR SOME LK BREEZE NEAR LK SUP AND SOME
LOCAL COOLING...BUT THE WSW 15-20KT H925 FLOW SHOULD LIMIT THE
INLAND PENETRATION OF THE LK BREEZE. MORE MODERATION IS LIKELY NEAR
LK MI E OF ESCANABA. ALTHOUGH THERE MAY BE SOME HI BASED CU...THE
AFTN SHOULD BE MOSUNNY WITH MIN RH DIPPING TOWARD 30 PCT AS DEWPTS
MIX OUT INTO THE LO-MID 40S AWAY FM LK INFLUENCE. THE DEEP MIXING
MAY ALLOW FOR SOME WIND GUSTS TO 15-20 MPH...BUT FIRE WX SHOULD NOT
BE A CONCERN GIVEN RECENT GENEROUS RAINFALL.
TNGT...UPR MI WL BE DOMINATED BY A STRENGTHENING SSW FLOW UNDER
TIGHTENING PRES GRADIENT BTWN THE HI PRES RETREATING TOWARD NEW
ENGLAND AND LO PRES TAKING SHAPE SW OF LK WINNIPEG. ALTHOUGH THE
AIRMASS WL BE DRY/SKIES MOCLR WITH PWAT DROPPING AS LO AS 0.50-0.75
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 OVER THE INTERIOR SCENTRAL AND E WHERE THE PRES
GRADIENT WL BE A BIT WEAKER/WINDS LIGHTER.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 439 AM EDT SUN SEP 7 2014
DRY WITH SLIGHTLY ABOVE TEMPERATURES THROUGH TUESDAY MORNING...THEN
BECOMING COOL AND WET THROUGH AT LEAST THE END OF THE WORK WEEK.
WILL CONTINUE TO EXPERIENCE WAA ON MONDAY...ON INCREASING S WINDS AS
UPPER MI REMAINS STUCK BETWEEN A LARGE AREA OF HIGH PRESSURE EXITING
THE NEW ENGLAND STATES...AND AN ELONGATED TROUGH SET UP FROM THE
CENTRAL PLAINS THROUGH ONTARIO AND HUDSON BAY. 850MB TEMPS WILL
AVERAGE AROUND 11C BY THE END OF THE DAY. S GUSTS NEAR 20KTS WILL BE
COMMON IN THE AFTERNOON. MAY END UP WITH SLIGHTLY WARMER TEMPS THAN
FCST ALONG THE SHORES OF LAKE SUPERIOR THANKS TO THE DOWNSLOPE FLOW.
DESPITE THE GFS AND ECMWF LIGHT QPF OUTPUTS MONDAY EVENING...HAVE
KEPT THE FCST DRY FOR NOW...ASSOCIATED WITH A 500MB SHORTWAVE AHEAD
OF THE SFC TROUGH SET UP ACROSS MN.
LOOK FOR THE SFC TROUGH TO SET UP ACROSS THE CWA TUESDAY AFTERNOON
INTO TUESDAY EVENING. KEPT TS POTENTIAL TO A MINIMUM TUESDAY-TUESDAY
EVENING OVER MAINLY W UPPER MI. THE BEST CHANCE OF OF WIDESPREAD
PRECIPITATION WILL BE EARLY WEDNESDAY MORNING THROUGH THURSDAY
MORNING AS THE CENTRAL PLAINS LOW OVER KS AT 00Z WEDNESDAY DRIFTS NE
INTO W WI BY 12Z WEDNESDAY AND LIKELY SWINGS ACROSS N LAKE MI WHILE
STRENGTHENING AT 00Z THURSDAY...BEFORE EXITING ACROSS N LAKE HURON
WEDNESDAY EVENING. THE INITIAL SHORTWAVE WILL CROSS UPPER MI
WEDNESDAY EVENING. QPF MAY NEAR AN INCH FROM 06Z WEDNESDAY THROUGH
12Z THURSDAY. BEHIND THE EXITING LOW MUCH COLDER AIR WILL BE ABLE TO
SINK IN. 850MB TEMPS OF -2 TO -4C WILL BE POISED ACROSS MUCH OF THE
S CANADIAN PRAIRIES WEDNESDAY EVENING. A SECONDARY 500MB LOW OVER S
SASKATCHEWAN/MANITOBA AT 06Z THURSDAY WILL SLOWLY TRACK TO UPPER MI
BY 12Z FRIDAY. THE COOLER CANADIAN AIR WILL BE ABLE TO SLIP IN. 50S
WILL BE COMMON FOR HIGH TEMPS THURSDAY THROUGH SATURDAY. THE LAST
TIME WE HAD 50S FOR HIGHS WAS JULY 15TH AND 8TH. IT/S A GOOD BET
THAT THEY WILL BE BACK FOR THURSDAY THROUGH SATURDAY. GIVEN THE
FAVORABLE UPSLOPE N-NW FLOW...EXPECT LINGERING SHOWERS NEAR LAKE
SUPERIOR THROUGH THE END OF THE WORK WEEK...WITH LAKE ENHANCED
CLOUDS AND SHOWERS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 722 AM EDT SUN SEP 7 2014
EXPECT VFR CONDITIONS THIS FCST PERIOD WITH A DRY SW FLOW ARND HI
PRES MOVING E THRU THE LOWER LKS. DAYTIME HEATING/MIXING WL ALLOW
FOR GUSTY WINDS TO 15-20 KT THIS AFTN AT MAINLY SAW AND IWD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 439 AM 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 WEAK TROUGH ACROSS LAKE SUPERIOR WILL SLOWLY DEEPEN
TUESDAY AFTERNOON...IN BETWEEN THE HUDSON BAY AND LOW PRESSURE
ORGANIZING ACROSS THE CENTRAL PLAINS. EXPECT THE CENTRAL PLAINS LOW
TO MOVE NE ACROSS THE UPPER GREAT LAKES WEDNESDAY AND WEDNESDAY
NIGHT...BEFORE EXITING INTO QUEBEC ON THURSDAY. AN EXTENDED PERIOD
OF N TO NW GALES WILL BE POSSIBLE WEDNESDAY INTO THURSDAY NIGHT.
&&
.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 MEMPHIS TN
1059 AM CDT SUN SEP 7 2014
.DISCUSSION...15Z SURFACE ANALYSIS PLACES A COLD FRONT ACROSS
SOUTHERN ALABAMA...MISSISSIPPI AND LOUISIANA WHILE A 1024 MB RIDGE
OF HIGH PRESSURE IS CENTERED OVER NORTHERN MISSOURI. AS OF 10 AM
CDT...MOSTLY CLOUDY/CLOUDY SKIES PREVAIL ACROSS AREAS SOUTH OF A
LINE FROM PARIS TENNESSEE BACK THROUGH WYNNE ARKANSAS...AND SUNNY
SKIES ELSEWHERE WITH TEMPERATURES IN THE 70S AT MOST LOCATIONS.
12Z WRF/GFS AND THE LATEST RUC STILL INDICATE A POSSIBILITY OF
ISOLATED RAIN SHOWERS AND PERHAPS A THUNDERSTORM MAINLY ACROSS
PORTIONS OF NORTH MISSISSIPPI THIS AFTERNOON. FORECAST OVERALL IS
IN GOOD SHAPE AND NO UPDATE ANTICIPATED AT THIS MOMENT.
CJC
&&
.PREV DISCUSSION... /ISSUED 623 AM CDT SUN SEP 7 2014/
UPDATE...
UPDATED FOR 12Z AVIATION DISCUSSION.
PREV DISCUSSION... /ISSUED 402 AM CDT SUN SEP 7 2014/
DISCUSSION...
CURRENTLY...THE COLD FRONT HAS PUSHED WELL SOUTH OF THE AREA AND
COOLER...DRIER AIR IS FILTERING INTO THE MIDSOUTH. TEMPS RANGE
FROM THE MID 60S NORTH TO LOWER 70S ACROSS MONROE COUNTY.
DEWPOINTS IN THE UPPER 50S ARE BEGINNING TO SEEP ACROSS THE MO
BORDER. A BAND OF MID AND HIGH CLOUDS IS ALSO PUSHING ACROSS THE
AREA WITH A FEW SPRINKLES.
TODAY...A FEW SHOWERS/THUNDERSTORMS ARE POSSIBLE ACROSS NORTH
MISSISSIPPI WHERE SOME INSTABILITY REMAINS. THE NAM IS MOST
BULLISH ON THIS POSSIBILITY...ESPECIALLY ACROSS THE EXTREME
SOUTHEAST PART OF THE AREA WHERE DEWPOINTS ARE STILL AROUND 70.
OTRW HIGH PRESSURE ALONG WITH DRIER AND COOLER AIR WILL BUILD IN
WITH DECREASING CLOUDS. HIGHS WILL RANGE FROM THE LOWER 80S NORTH
TO MID 80S SOUTH.
TONIGHT THROUGH MONDAY NIGHT...HIGH PRESSURE AND MOSTLY CLEAR
SKIES WILL RESULT IN A PLEASANT NIGHT WITH LOWS IN THE 60S
AREA WIDE. PLENTY OF SUNSHINE EXPECTED ON MONDAY WITH TEMPS
IN THE MID TO UPPER 80S AND COMFORTABLE HUMIDITY LEVELS.
TUESDAY AND WEDNESDAY...SURFACE HIGH PRESSURE HEADS EAST AS UPPER
LEVEL HIGH PRESSURE NUDGES IN AND SOUTHERLY WINDS DEVELOP BRINGING
INCREASING HUMIDITY. TEMPS WILL WARM BACK ABOVE NORMAL...INTO THE
LOWER 90S...FOR PERHAPS WHAT WILL BE THE LAST GASP OF SUMMER. RAIN
CHANCES WILL BE MINIMAL DURING THIS TIME FRAME.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...A COLD FRONT WILL PUSH
THROUGH THE REGION WITH GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS.
SINCE THE 00Z MODELS ARE A LITTLE SLOWER BRINGING THE FRONT
INTO THE MIDSOUTH...ADJUSTED POPS DOWN ACROSS THE SOUTHERN HALF OF THE
AREA WEDNESDAY NIGHT. ALSO SINCE THE MODELS ARE MOVING THE FRONT
THROUGH SLOWER RAISED POPS ACROSS THE SOUTHERN HALF THURSDAY
NIGHT. PRECIP WATER VALUES ARE FORECAST TO BE ABOVE 2 INCHES ALONG
THE FRONT SO WILL NEED TO KEEP AN EYE ON THE POSSIBILITY OF
LOCALLY HEAVY RAIN. PUSHED TEMPS UP A FEW DEGREES ON THURSDAY
SINCE THE FRONT IS SLOWER.
FRIDAY AND SATURDAY...RAIN CHANCES WILL TAPER OFF ON FRIDAY AND
SKIES WILL BEGIN TO CLEAR AS VERY COOL HIGH PRESSURE STARTS TO
BUILD IN. HIGHS ON FRIDAY AND SATURDAY WILL ONLY BE IN THE 70S...TO
AROUND 80 ACROSS NE MS. LOWS FRIDAY NIGHT WILL DIP INTO THE 50S
AND WOULD NOT BE SURPRISED TO SEE SOME OF THE COOLER LOCATIONS IN
THE UPPER 40S IF THE 00Z GFS VERIFIES WELL.
SJM
&&
.AVIATION...
12Z TAFS
POST FRONTAL AIRMASS WILL KEEP THE SITES VFR...WITH THE ONLY
EXCEPTION BEING MORNING MVFR CIGS AT TUP. ISOLATED SHOWERS AND
THUNDERSTORMS WILL DEVELOP BY MIDDAY OVER NORTH MISSISSIPPI...SO
PLACED VCSH IN AT TUP. CLEARING SKIES TONIGHT...WITH LIGHT FOG/MVFR
VSBY POSSIBLE AT MKL. WINDS WILL BE NORTHEAST AT 5-9 KTS DIMINISHING
TO 3-5 KTS BY SUNSET.
JAB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
926 AM CDT SUN SEP 7 2014
.DISCUSSION...
FRONTAL BOUNDARY NOW POSITIONED TO THE SOUTH OF TN. UPPER PATTERN
FEATURES A RATHER WEAK BROAD TROUGH WITH A FEW IMPULSES RACING
EASTWARD ALONG THE WESTERLY FLOW. SAT IMAGERY DEPICTS A SWATH OF
CLOUDINESS MOVING ACROSS THE AREA WITH A FEW ISOLATED
SHOWERS...HERE AND THERE...AS WELL. MODELS KEEP THE CLOUDINESS IN
ACROSS THE AREA THROUGH THE DAY WITH PERHAPS SOME BREAKS IN THE
CLOUD COVER BY LATE AFTERNOON. HRRR NOT SHOWING MUCH SHOWER
DEVELOPMENT...BUT THE MODEL DATA DOES CARRY SOME QPF THROUGH THE
DAY...MAINLY EASTERN AREAS.
CURRENT FCST LOOKS OK BUT I WILL GO AHEAD AND LOWER TODAY`S HIGH
TEMPS. 18Z GRAPHICAL TEMPS SHOW MID 70S FOR BNA SO I WILL AIM FOR
HIGHS THAT WILL APPROACH 80 DEGREES. WITH THE CLOUD COVER AND
LIGHT NORTHERLY FLOW...THE CAA MAY WIN OUT AND TEMPS WILL STRUGGLE
TO WARM TODAY.
UPDATES OUT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 647 AM CDT SUN SEP 7 2014/
UPDATE...FOR 12Z AVIATION FORECASTS.
AVIATION...LOW-TO-MID LEVEL MOISTURE SLOW TO PULL OUT OF THE MID
STATE BEHIND YESTERDAY`S COLD FRONT. AS A RESULT, EXPECT IFR
AND MVFR CIGS AT CSV THROUGH 20Z AND MAINLY MVFR CIGS AT BNA THROUGH
20Z. MEANWHILE, BLV ENOUGH DRIER AIR HAS ALREADY FILTERED INTO THE
CKV AREA TO ALLOW FOR MAINLY VFR CONDITIONS THROUGH THE MORNING
AND THE UPCOMING AFTERNOON. BTWN 20Z/07 AND 06Z/08, BLV DRIER AIR
WILL HAVE PUSHED DEEP ENOUGH INTO THE MID STATE TO PRODUCE VFR
CONDITIONS AT ALL TERMINALS. AFTER 06Z, LOOK FOR PATCHY BR TO
DEVELOP AT CKV AND CSV, LIKELY PRODUCING MVFR VSBYS AT THOSE TWO
LOCATIONS AFTER 08Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 81 63 86 65 / 10 10 10 05
CLARKSVILLE 80 58 84 60 / 10 05 05 05
CROSSVILLE 77 61 80 63 / 20 20 30 10
COLUMBIA 82 63 86 65 / 10 10 10 05
LAWRENCEBURG 83 64 86 65 / 20 05 10 10
WAVERLY 81 60 85 62 / 10 05 05 05
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
653 AM CDT SUN SEP 7 2014
.AVIATION...
/12Z TAFS/
IFR conditions are occurring early this morning at the TAF sites
with ceilings between 500 ft and 1000 ft. Rain showers continue
to develop across various parts of West Central Texas, and
initially carrying a mention of SHRA or VCSH in the TAFs. The
coverage of showers should decrease between 12Z and 15Z, with
a possibility of scattered redevelopment through early this
evening. Although extensive cloud cover will persist through
early afternoon, expect a gradual improvement to MVFR conditions
as the ceilings slowly increase. VFR ceilings are expected by
late afternoon, and a decrease in cloud cover is anticipated this
evening and overnight. North-northeast winds this morning will
veer to the east by this evening, and to the southeast tonight.
Patchy fog development is possible late tonight, especially if
sufficient clearing occurs. But given the uncertainty at this
time and with several time groups already included in the TAF
package, decided to hold off at this point with adding fog and
visibility restrictions.
&&
.PREV DISCUSSION... /ISSUED 459 AM CDT SUN SEP 7 2014/
SHORT TERM...
(Today and Tonight)
Showers are occurring across our central and northern counties, in a
rather moist airmass north of a stalled frontal boundary. The most
noteworthy is a persistent east-west band of showers with moderate
to heavy rain, extending from just east of San Angelo to just south
of Brownwood. The HRRR and TTU WRF pick up on these showers to some
extent, with a trend of dissipation between 12Z and 15Z. May need to
extend the higher PoPs from the overnight period past 12Z this
morning. Will monitor radar trends and update if needed.
During the day today, have a possibility for scattered showers and a
few thunderstorms in the moist airmass. Considerable cloud cover
will hold through early afternoon, and then should have a decrease
in cloud cover from the west and southwest later in the afternoon.
The extent and duration of cloud cover is expected to have an effect
on temperatures today. Going with highs in the lower to mid 80s.
Have a lingering slight chance PoP early tonight for our central and
southern counties. Otherwise, a decrease in cloud cover is expected
overnight. Given the recent rainfall and a moist airmass, will have
a possibility for patchy fog development late tonight, depending on
the extent of clearing. Temperatures will cool to near dewpoint
values overnight with light (southeast) winds.
LONG TERM...
(Monday through next Sunday)
..A strong cold front will bring much cooler temperatures and
another chance of rainfall to the area by the end of the week...
South winds and much warmer temperatures return to the area Monday
through Wednesday, as a lee surface trough develops ahead of an
upper level trough moving east across the Rockies. Temperatures on
Monday will be near seasonal norms for this time of year, with
afternoon highs in the lower 90s. An isolated shower or thunderstorm
will be possible across far southeast counties during the
afternoon, otherwise dry conditions will prevail. Breezy south to
southwest winds and above normal temperatures return to the area
Tuesday and Wednesday with highs both days in the mid and upper
90s.
Big changes coming towards the end of the week as the aforementioned
upper trough tracks east across the Plains, sending a strong cold
front south across our area on Thursday. It will feel more like
fall behind the front Friday and Saturday with high temperatures
only in the middle/upper70s to lower 80s, with overnight lows in
the lower to middle 60s. We`ll also see another chance for showers
and thunderstorms along and behind the front Thursday into Friday.
Kept chance POPs in the forecast for now, but will likley need to
be raised further as model confidence increases. Below normal
temperatures continue for next Sunday but it will be a liitle
warmer with highs mainly in the middle 80s.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 83 68 92 73 95 / 50 10 10 5 5
San Angelo 84 68 92 71 95 / 60 20 10 5 5
Junction 85 69 91 71 94 / 40 20 10 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
Aviation and Short Term: 19
Long Term: JW
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
616 AM CDT SUN SEP 7 2014
.AVIATION...
MORNING STRATUS IN METROPLEX WILL BE SLOW TO MIX OUT THIS MORNING
DUE TO CLOUD COVER. CEILINGS COULD DIP INTO THE IFR RANGE NEAR SUNRISE
AS SUPPORTED BY THE RAP AND GFS MOS. WITH THE FRONT FAIRLY FAR
SOUTH WE THINK TSRA ACTIVITY WILL BE VERY LIMITED IN THE METROPLEX
AREA AND HAVE LEFT THE TAFS TSRA FREE. RAIN SHOULD BE DONE THIS
EVENING AND THEN STAY DRY THROUGH TOMORROW.
AT KACT...BETTER MIXING SHOULD KEEP CEILINGS ABOVE IFR THIS
MORNING. CHANCE OF TSRA IS HIGHER AND HAVE CONTINUED THE VCTS FOR
THE AFTERNOON. 84
&&
.PREV DISCUSSION... /ISSUED 406 AM CDT SUN SEP 7 2014/
THE COLD FRONT THAT MOVED THROUGH NORTH AND CENTRAL TEXAS
YESTERDAY CONTINUED ITS SLOW SOUTHWARD PROGRESS INTO SOUTH TEXAS
THIS MORNING. NORTHERLY WINDS OF 5 TO 10 MPH PREVAILED ACROSS THE
REGION. AS OF 4 AM...SCATTERED SHOWERS AND A FEW THUNDERSTORMS
CONTINUED MAINLY SOUTH OF I-20 WITH ONLY ISOLATED SHOWERS FARTHER
TO THE NORTH.
EXPECT MOSTLY CLOUDY SKIES TODAY WITH SCATTERED SHOWERS AND A FEW
THUNDERSTORMS ESPECIALLY SOUTH OF I-20 WITH RAIN CHANCES
DECREASING FROM THE NORTH DURING THE DAY. WITH CLOUD COVER AND
THE COOLER AIR MASS IN PLACE...TEMPERATURES SHOULD ONLY WARM INTO
THE MID 80S TO LOWER 90S. WINDS WILL BECOME NORTHEASTERLY AT 5 TO
10 MPH AREA WIDE TODAY AND BECOME EASTERLY THIS EVENING AS HIGH
PRESSURE SLIDES EAST. HAVE LEFT SOME LOW POPS ACROSS THE AREA
SOUTH OF I-20 INTO TONIGHT. LOWS WILL BE IN THE UPPER 60S TO
LOWER 70S.
THE CLOUDS WILL BE ON THE DECREASE FROM THE NORTH MONDAY ALLOWING
FOR SKIES TO BECOME MOSTLY SUNNY. SOME ISOLATED SHOWERS/THUNDERSTORMS
WILL BE POSSIBLE SOUTH OF A GOLDTHWAITE TO ATHENS LINE. WINDS
WILL BECOME SOUTHEASTERLY AND SOUTHERLY AS THE SURFACE HIGH MOVES
FARTHER TO THE EAST AND A LEE SIDE TROUGH DEVELOPS. TEMPERATURES
WILL WARM INTO THE LOWER TO MID 90S. EXPECT ABOVE SEASONAL NORMAL
TEMPERATURES MONDAY AFTERNOON THROUGH WEDNESDAY.
AN UPPER LEVEL TROUGH THAT IS CURRENTLY HUNDREDS MILES OFF THE
COAST OF NORTHERN CALIFORNIA WILL MOVE EAST DURING THE NEXT
SEVERAL DAYS AND WILL SLIDE ACROSS THE CENTRAL PLAINS MIDWEEK. AS
IT DOES...A COLD FRONT WILL MOVE DOWN THE PLAINS INTO NORTH TEXAS
WEDNESDAY NIGHT/THURSDAY MORNING. THIS FRONT WILL MOVE THROUGH
CENTRAL TEXAS THURSDAY AFTERNOON AND WILL BRING MUCH COOLER AIR
INTO THE REGION ALONG WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
HIGHS ON FRIDAY MAY NOT GET OUT OF THE 70S ACROSS THE NORTHERN
THIRD OF THE FORECAST AREA...WITH LOW TO MID 80S FARTHER TO THE
SOUTH. RAIN CHANCES WILL DIMINISH FRIDAY NIGHT AS DRIER AIR
DEEPENS. LOWS SATURDAY MORNING MAY REACH THE UPPER 50S IN THE
SOME OF THE NORMALLY COOLER AREAS ACROSS THE NORTH AND WEST...AND
WE WILL SEE 60S ELSEWHERE. TEMPERATURES WILL START TO MODERATE
SATURDAY AFTERNOON.
58
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 88 74 95 78 97 / 30 10 10 5 5
WACO, TX 90 72 96 75 97 / 40 20 20 10 5
PARIS, TX 86 69 93 72 94 / 30 10 10 5 5
DENTON, TX 88 71 95 75 96 / 30 10 10 5 5
MCKINNEY, TX 86 69 93 73 95 / 30 10 10 5 5
DALLAS, TX 88 74 94 78 97 / 30 10 10 10 5
TERRELL, TX 88 71 95 74 96 / 30 10 10 10 5
CORSICANA, TX 88 72 94 75 96 / 30 20 10 10 5
TEMPLE, TX 91 71 96 74 97 / 40 20 20 10 5
MINERAL WELLS, TX 87 70 94 72 96 / 30 10 10 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
639 AM CDT SUN SEP 7 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 240 AM CDT SUN SEP 7 2014
CURRENTLY AS OF 07Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED NORTHWEST FLOW FROM BRITISH COLUMBIA THROUGH THE GREAT LAKES
REGION...THOUGH A FAIRLY POTENT TROUGH WAS BEGINNING TO BUCK THIS
FLOW DROPPING SOUTH THROUGH BRITISH COLUMBIA. THE NORTHWEST FLOW HAS
HELPED PRODUCE A DRYING...SUBSIDENT REGIME OVER THE FORECAST
AREA...SEEN NICELY ON REGIONAL 00Z SOUNDINGS AS WELL AS PRECIPITABLE
WATER PLOTS SHOWING BETWEEN 0.5-0.75 INCHES OR 50-90 PERCENT OF
NORMAL. THIS DRY AIR HAS RESULTED IN BASICALLY CLEAR SKIES ACROSS
THE ENTIRE UPPER MIDWEST. SURFACE PATTERN FEATURES HIGH PRESSURE
CENTERED OVER THE MID MISSISSIPPI VALLEY WITH A WARM FRONT FROM
NORTHERN MN SOUTHWESTWARD INTO WYOMING. LIGHT SURFACE WINDS
ASSOCIATED WITH THE HIGH...CLEAR SKIES AND DRY AIR HAS ALLOWED FOR
TEMPERATURES TO DIP INTO THE MID 40S AT THE TYPICAL COLD SPOTS IN
CENTRAL WI. ABOVE THE SURFACE...HOWEVER...TEMPERATURES ARE WARMING
DUE TO A DOWNSLOPE WESTERLY FLOW FROM THE MOUNTAINS. 925MB TEMPS ARE
16-18C PER LATEST RAP ANALYSIS COMPARED TO AROUND 12C 24 HOURS AGO.
QUIET CONDITIONS LOOK TO CONTINUE FOR THE NEXT 24 HOURS AS THE
REGION REMAINS UNDER THE INFLUENCE OF THE SURFACE HIGH AND THE DRY
AIR ASSOCIATED WITH IT. STILL AT 12Z MONDAY...PRECIPITABLE WATER
PROGS ONLY SHOW VALUES OF 0.5-0.75 INCHES ACROSS THE REGION. IT
SHOULD BE NOTED THAT THE SURFACE HIGH DOES DRIFT OFF TO THE
EAST...WHICH ALLOWS FOR A RETURN FLOW TO DEVELOP ACROSS THE PLAINS.
THIS RETURN FLOW HELPS PULL A SURGE OF 1-1.25 INCH PRECIPITABLE
WATER THROUGH THE PLAINS INTO SOUTHWEST MN BY 12Z MONDAY.
ADDITIONALLY...A SHORTWAVE TRACKING THROUGH SOUTH DAKOTA TONIGHT
SHOULD RESULT IN SHOWERY CONVECTION BREAKING OUT AROUND THE SIOUX
FALLS AREA. SOME CIRRUS SPREADING OFF THIS PRECIPITATION LOOKS TO
SPREAD INTO THE AREA AFTER MIDNIGHT.
925MB TEMPS ARE PROGGED TO CHANGE VERY LITTLE TODAY FROM WHERE THEY
ARE NOW...HOLDING IN THAT 16-18C RANGE. STILL...THESE ARE 2-4C
WARMER THAN WHAT WE STARTED OFF WITH AT 12Z SATURDAY. THUS WITH
PLENTY OF SUN AGAIN HIGHS SHOULD END UP A COUPLE DEGREES WARMER. AN
INCREASING SOUTHWEST FLOW TONIGHT WILL HELP TEMPERATURES STAY A BIT
WARMER AS WELL...ESPECIALLY OVER THE HIGHER TERRAIN ALONG/WEST OF
THE MS RIVER WHERE A TIGHTER GRADIENT EXISTS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 240 AM CDT SUN SEP 7 2014
THE SHORTWAVE THAT COMES ACROSS SOUTH DAKOTA TONIGHT LOOKS TO SLIDE
ACROSS THE FORECAST AREA ON MONDAY...BRINGING THE SURGE OF SOMEWHAT
HIGHER PRECIPITABLE WATER INTO THE REGION AND THE ASSOCIATED SHOWERS
AS WELL. ITS HARD TO SAY HOW MUCH OF THE SHOWER ACTIVITY WILL MOVE
INTO THE AREA GIVEN THE INITIAL DRY AIRMASS IN PLACE. THIS IS
REFLECTED WELL IN THE 07.00Z NAM KEEPING THE FORECAST AREA DRY AND
SREF TRENDS THROUGH THE DAY DRYING THE PRECIPITATION UP. THE
TYPICALLY WETTER GFS SPREADS PRECIPITATION INTO THE WESTERN FORECAST
AREA...BUT SOUNDINGS ARE ALSO RELATIVELY DRY. FOR NOW...HAVE
CONFINED ANY PRECIPITATION CHANCES TO AFTER 18Z WEST OF THE MS RIVER
AND KEPT THE CHANCES AROUND 20. GIVEN THAT THE INSTABILITY AXIS
LOOKS TO STAY WEST OF I-35 DURING THE DAY...DO NOT HAVE ANY THUNDER
MENTIONED. A BETTER SHOT FOR PRECIPITATION EXISTS MONDAY NIGHT...
MAINLY ACROSS IOWA...AS ANOTHER WEAK SHORTWAVE MOVES THROUGH THAT
STATE AND THE NOSE OF A SURGE OF 850MB MOISTURE TRANSPORT POINTS IN
FOR A TIME. TEMPERATURES ON MONDAY LOOK SIMILAR TO TODAY GIVEN
SIMILAR 925MB TEMPS...POTENTIAL FOR SOME SUN AND A SOUTHERLY BREEZE
FOR MIXING. LOWS MONDAY NIGHT SHOULD BE NOTICEABLY WARMER WITH
HIGHER DEWPOINTS...CONTINUED SOUTHERLY BREEZE AND CLOUD COVER ALL
HELPING TO KEEP TEMPS UP.
THE MIDDLE OF THE WEEK CONTINUES TO BE THE ACTIVE PERIOD OF THE
FORECAST...CAUSED BY A VARIETY OF UPPER LEVEL FEATURES INFLUENCING
OR IMPACTING THE AREA. THE FIRST FEATURE IS THE CURRENT SHORTWAVE
TROUGH DROPPING THROUGH BRITISH COLUMBIA WHICH DIGS INTO THE HIGH
PLAINS TUESDAY NIGHT...SETTING UP SOUTHWEST UPPER FLOW AND A STRONG
INCREASE IN LOW LEVEL RETURN FLOW TOWARDS THE AREA. THE SECOND
FEATURE IS A COLLECTION OF SHORTWAVES THAT DEVELOP OFF THE COLORADO
MOUNTAINS ON TUESDAY...WHICH GET CAUGHT UP IN THE SOUTHWEST FLOW AND
LIFTED INTO THE FORECAST AREA TUESDAY NIGHT. THE 07.00Z NAM AND
ECMWF EVEN SUGGESTS THESE SHORTWAVES WILL PHASE WITH THE
AFOREMENTIONED TROUGH. THE THIRD FEATURE IS A PLUME OF EAST PACIFIC
TROPICAL MOISTURE SEEN EAST OF HURRICANE NORBERT ON WATER VAPOR...
WHICH LOOKS TO GET PULLED UP INTO THE FORECAST AREA ALSO ON TUESDAY
NIGHT.
AS THE AFOREMENTIONED DISCUSSION HIGHLIGHTS...TUESDAY NIGHT IS THE
CENTER POINT FOR PRECIPITATION. ALTHOUGH THERE ARE STILL SOME SLIGHT
MODEL DIFFERENCES...PARTICULARLY WITH TRACK AND TIMING OF THE
SURFACE SYSTEM...ALL MODELS REMAIN CONSISTENT IN SPREADING SHOWERS
AND EMBEDDED STORMS INTO THE REGION TUESDAY NIGHT. THEREFORE...HAVE
CONTINUED TO RAISE PRECIPITATION CHANCES. CAPE IS FAIRLY MEAGER
GIVEN LAPSE RATES NOT MUCH HIGHER THAN MOIST ADIABATIC...WHICH WILL
LIMIT SEVERE WEATHER. ON THE OTHER HAND...WARM CLOUD DEPTHS
APPROACHING 4-4.5 KM...PRECIPITABLE WATER CLIMBING TO 2 INCHES AND
STRONG 850MB MOISTURE TRANSPORT NOSING INTO THE AREA FAVOR HEAVY
RAINFALL POTENTIAL. LUCKILY THE FLOW LOOKS PROGRESSIVE ENOUGH TO
PREVENT FLOODING. WEDNESDAY IS TRICKY AS THE SYSTEM COULD BE HEADING
OFF TO THE EAST...ALLOWING DRIER AND SUBSIDENT AIR TO INFILTRATE THE
REGION. STILL A CONSENSUS EXISTS FOR SHOWERS AND STORMS TO BE AROUND
ACROSS WISCONSIN. IF THE SYSTEM WOULD SLOW UP...THERE WOULD BE AN
OPPORTUNITY FOR DESTABILIZATION AND SEVERE WEATHER GIVEN STRONG WIND
FIELD. HOWEVER...THIS SEEMS TO BE A VERY LOW PROBABILITY AT THIS
POINT. IN THE RAINFALL DEPARTMENT...LOOKS LIKE WE SHOULD PICK UP 1-2
INCHES FROM THIS SYSTEM.
IN THE WAKE OF THE SYSTEM...ITS ALL ABOUT THE COLD AIR. THE FIRST
SURGE COMES THROUGH WEDNESDAY NIGHT WITH 925MB TEMPS DROPPING TO 4-
6C BY 12Z THURSDAY. THIS CAUSES BOTH LOWS WEDNESDAY NIGHT AND HIGHS
ON THURSDAY TO TAKE A BIG HIT. EVEN COLDER AIR SURGES IN FOR
FRIDAY...RESULTING FROM AN UPPER TROUGH SWINGING ACROSS THE AREA.
THIS FEATURE SENDS 925MB TEMPS DOWN TO 2-4C BY 12Z FRI WITH ONLY
SLIGHT MODERATION DURING THE DAY. A BRISK NORTHWEST WIND COMBINED
WITH SOME POTENTIAL FOR SHOWERS...PARTICULARLY NORTH OF I-90
WEDNESDAY NIGHT AND THURSDAY NIGHT INTO FRIDAY...WILL REALLY MAKE IT
FEEL LIKE FALL. HIGH PRESSURE THEN LOOKS TO BUILD IN FOR FRIDAY
NIGHT...WHICH WOULD APPEAR TO STAND THE BEST CHANCE FOR FROST
FORMATION IN LIKELY THE TYPICAL COLD SPOTS. DRY CONDITIONS AND SLOW
MODERATION OF TEMPERATURES ARE EXPECTED ON SATURDAY AS THE
UPPER TROUGH EXISTS AND SUNSHINE HELPS WARM THE AIRMASS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 639 AM CDT SUN SEP 7 2014
HIGH PRESSURE OVER THE MID MS VALLEY WILL SLOWLY SLIDE EAST TODAY/
TONIGHT. AS IT DOES...IT WILL MAINTAIN CONTROL OF THE WEATHER ACROSS
THE TAF SITES THRU MON MORNING...WITH GENERALLY CLEAR SKIES/GOOD VFR
CONDITIONS. AS THE CENTER OF THE HIGH MOVES AWAY...GRADIENT WINDS
WILL BE MORE SOUTH TO SOUTHWEST TODAY VS. THE WEST AND NORTHWEST OF
THE PAST COUPLE DAYS. GRADIENT REMAINS ON THE WEAK SIDE WITH WINDS
MOSTLY IN THE 8-12KT RANGE TODAY AND 5-8KT RANGE TONIGHT. THESE
WINDS TONIGHT SHOULD LIMIT ANY LATE NIGHT/EARLY MORNING BR/FG IN THE
LARGER RIVER VALLEYS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1233 PM EDT SUN SEP 7 2014
.SYNOPSIS...
COOL AND DRY HIGH PRESSURE WILL BUILD INTO THE REGION THIS
AFTERNOON INTO MONDAY. THIS HIGH WILL LINGER INTO THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1230 PM UPDATE...HAVE ONLY MADE SLIGHT CHANGES TO SKY COVER AND
TEMPERATURES TO ACCOUNT FOR CURRENT TRENDS. NO OTHER ADJUSTMENTS
WERE NEEDED.
PREVIOUS DISCUSSION...
MUCH COOLER AND DRIER THIS TERM.
06Z SURFACE ANALYSIS SHOWED A COLD FRONT HANGING OFF THE COAST
W/AN AREA OF SHOWERS MOVING UP ALONG THE COAST. THESE SHOWERS WERE
IN RESPONSE TO A WEAK SFC LOW THAT DEVELOPED ON THE FRONT. LATEST
SREF WAS HANDLING THE SHOWERS QUITE WELL W/THE SETUP. DECIDED TO
CARRY 60% POPS RIGHT ALONG THE COAST FOR EARLY THIS MORNING AND
THEN DROP THEM OFF AS THE LOW PULLS NE AND THE FRONT PULLS FURTHER
S. IR SATELLITE IMAGERY SHOWED CLOUDS ACROSS THE CWA W/CLEARING
TAKING PLACE ACROSS THE NORTHERN TIER. THE CLOUDS WILL PULL OUT OF
THE AREA BY LATE MORNING AS DRIER AIR CONTINUES TO POUR IN. A
SECOND FRONTAL BOUNDARY IS SHOWN BY THE NAM AND HRRR 3KM TO DROP S
ACROSS THE REGION THIS AFTERNOON. THE MODEL SOUNDINGS SUPPORT
MOISTURE IN THE 900-800MB LAYER ACROSS THE NORTHERN 1/2 OF THE CWA
WHILE DOWNEAST AND THE COAST WILL SEE SOME SCATTERED CLOUDINESS.
NW WINDS WILL PICK UP BEHIND THIS FRONT W/TEMPERATURES THIS
AFTERNOON ABOUT 10-15 DEGREES COLDER THAN THEY HAVE BEEN THE LAST
SEVERAL DAYS. WE ARE TALKING UPPER 60S TO AROUND 70.
HIGH PRES IS FORECAST TO SLIDE ACROSS THE REGION TONIGHT
W/CLEARING SKIES AND MUCH DRIER AIR. NW WINDS WILL DROP OFF
TONIGHT W/DEWPOINTS DROPPING INTO THE 30S BY EARLY MONDAY MORNING.
DECIDED TO CARRY PATCHY FOG W/THE COOLING AND WET GROUND FROM
SATURDAY`S RAIN. TEMPERATURES BY SUNRISE WILL HIT THE MID AND
UPPER 30S W/LOCATIONS SUCH AS THE ALLAGASH AND ST. JOHN VALLEY
SEEING LOWER 30S. THIS RAISES CONCERN FOR FROST BY EARLY MONDAY
MORNING MAINLY ACROSS THE NORTH AND WEST. COLLABORATED W/GYX AND
BTV ON THIS AND THINKING IS THAT THE FOG COULD OFFSET THE EXTENT
OF THE FROST W/A HEAVY DEW DEVELOPING. PLUS, WINDS COULD ACTUALLY
STAY UP A WHILE LONGER BEFORE DECOUPLING WHICH IN TURN LIMIT THE
DURATION OF THE FROST. THEREFORE, THE DECISION WAS NOT TO ISSUE A
FROST ADVISORY W/THIS PACKAGE BUT KEEP THE MENTION OF FROST IN
THE FORECAST. DAYCREW CAN ASSESS THIS FURTHER TODAY.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE AREA THROUGH THE
SHORT TERM PERIOD. A LOW PRESSURE SYSTEM WILL MOVE NORTH ALONG THE
ATLANTIC COAST...AT THIS TIME APPEARS WILL REMAIN SOUTH OF THE
GULF OF MAINE.
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 /WEDNESDAY THROUGH SATURDAY/...
A HIGH PRESSURE RIDGE WILL BE IN PLACE OVER THE AREA AT THE START
OF THE LONG TERM. A LOW TRACKING ACROSS THE GREAT LAKES WILL BRING
ITS ASSOCIATED FRONT INTO WRN MAINE THURS MRNG. THE GUIDANCE MOVES
THE FRONT INTO NEW BRUNSWICK FRI MRNG....UNSETTLED WEATHER WILL
CONTINUE AS THE UPPER LEVEL LOW ELONGATES ALONG THE US AND
CANADIAN BOARDER EXTENDING FRONT THE CENTRAL GREAT LAKES TO
ATLANTIC CANADA. THE UPPER LOW WILL REMAIN IN THE AREA THROUGH THE
END OF THE PERIOD. TROUGHS OF LOWER PRESSURE WILL ROTATE AROUND
THE LOW BRINGING PERIODS OF UNSETTLED WEATHER INTO NRN AND CENTRAL
MAINE THROUGH THE END OF THE PERIOD.
LOADED THE SUPERBLEND FOR THE EXTENDED PERIOD OF THE FORECAST.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
NEAR TERM: VFR W/TEMPO MVFR OR PERHAPS IFR BY EARLY MONDAY MORNING
FOR FOG DUE TO WET GROUND.
SHORT TERM: HIGH PRESSURE WILL DOMINATE THE WEATHER THROUGH THE
PERIOD. VFR CONDITIONS ALL SITE. LIGHT WINDS...COOLER TEMPS WILL
LIKELY ALLOW MORNING FOG PARTICULARLY AROUND WATER BODIES REDUCING
VISIBILITIES DURING THE EARLY MORNING HOURS.
&&
.MARINE...
NEAR TERM: WINDS HAVE DROPPED TO 10 KTS BUT SEAS STILL RUNNING
AROUND 5 FT. THINKING IS THAT SEAS WILL DROP BACK TODAY AS NW TAKE
HOLD AND HIGH PRES BUILDS E. WINDS WILL REMAIN 10 KT OR LESS.
SHORT TERM: WINDS AND SEAS BELOW SCA CRITERIA THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS/HEWITT
SHORT TERM...NORTON
LONG TERM...NORTON
AVIATION...HASTINGS/HEWITT/NORTON
MARINE...HASTINGS/HEWITT/NORTON
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
350 PM EDT SUN SEP 7 2014
.SYNOPSIS...
A COLD FRONT HAS STALLED ALONG THE SOUTHEAST AND MID ATLANTIC
COASTS AS OF LATE THIS AFTERNOON AND IT WILL REMAIN NEARLY
STATIONARY THROUGH TUESDAY NIGHT. AN AREA OF LOW PRESSURE WILL
SLOWLY TRACK NORTHEAST ALONG THAT BOUNDARY FROM MONDAY AFTERNOON
THROUGH TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
COOLER...NOTICEABLY DRIER WX THIS AFTN. CDFNT HAS SETTLED WELL S
OF THE RGN...AND NNE WNDS (A LITTLE BIT GUSTY RIGHT AT THE CST)
PREVAIL OVR THE FA AS SFC HI PRES BUILDS INTO NEW ENG. OTHER THAN
AN ISOLD SHRA INVOF SE VA/NE NC...LARGE AREA OF RA CONFINED TO
JUST S OF THE ALBEMARLE SND MID AFTN. OTRW...PARTLY CLOUDY
N...MOSTLY CLOUDY S THROUGH THIS EVE.
SFC LO PRES WILL BEGIN TO DEVELOP INVOF INTERIOR SE CONUS LT
TNGT...AND BACKING OF MID LVL FLO WILL START TO PULL MOISTURE BACK
N. HAVE TRENDED A BIT SLOWER THAN THE MDLS W/ THE RETURN OF THE
MOISTURE LT TNGT. BY EARLY MON MRNG...WILL HAVE HIGHEST POPS
(60-80%) FAR SE VA/NE NC...TO 15-30% POPS ACRS NNW PORTIONS.
LO TEMPS IN THE L/M60S N...TO THE U60S TO ARND 70F FAR SE.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
AN UNSETTLED/WET PATTERN FOR THE FA THROUGH EARLY THIS WEEK. LO
PRES CONTG TO DEVELOP ALONG THE SE CONUS CST MON...THEN TRACKS
SLOLY TO THE NE ALG THE NC CSTL PLAIN AND EVENTUALLY OFF THE VA
CAPES LT TUE. THE COMBINATION OF INCRSG LO LVL MOISTURE FM THE
ATLC AND STRONG LIFT (ALONG/JUST N OF THE BOUNDARY AND ASSOCIATED
WITH THE MID LVL S/W)...WILL PRODUCE NUMEROUS SHOWERS OVR THE
AREA. HIGHEST POPS/CHC FOR HEAVIEST RAINFALL CONT TO BE OVR
ERN/SERN COUNTIES DURING THIS TIME. POPS DIMINISHING FM W TO E
BEGINNING LT TUE...AS THE LO MOVES OFF THE CST. WILL NOT RULE OUT
ISOLD THUNDER ESE AREAS...BUT WILL KEEP MENTION OUT OF FCST ATTM.
NE WNDS WILL BE GUSTY (MNLY ERN HALF OF FA) THROUGH THE TUE...TO
POSSIBLY 30-35 MPH ON THE EASTERN SHORE. HI TEMPS MON AND TUE
RANGING THROUGH THE 70S. LO TEMPS MON NGT MNLY FM 65 TO 70F.
GRADUAL IMPROVEMENT W/ DCRSG CLDNS WED. RETURN OF SUNSHINE XPCD TO
BOOST HI TEMPS BY CLOSER TO CLIMO NORMALS (ARND 80F AT THE
CST...M80S INLAND).
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MEDIUM RANGE GUIDANCE IN FAIRLY GOOD AGREEMENT THROUGH THE
PERIOD. THE MAIN FEATURE WILL BE A COLD FRONT SET TO CROSS THE
LOCAL AREA LATE IN THE WEEK...BRINGING COOLER/DRIER CONDITIONS TO
THE REGION BY NEXT WEEKEND.
UPPER FLOW WILL BE CHARACTERIZED BY AN AMPLIFYING TROUGH OVER THE
CNTRL CONUS...DOWNSTREAM OF AN ANOMALOUS RIDGE OVER THE WRN
PACIFIC AND GULF OF ALASKA. OVER THE LOCAL AREA...A LEADING
SHORTWAVE WILL FLATTEN THE UPPER FLOW BRIEFLY WEDS BEFORE SWLY
FLOW INCREASES IN ADVANCE OF THE APPROACHING UPPER TROUGH THURS-
FRI. AN ASSOCIATED COLD FRONT AND PARENT LOW WILL REACH THE GREAT
LAKES/OH VALLEY LATE WEDS INTO WEDS NIGHT. MEANWHILE...WEDGE OVER
THE LOCAL AREA BREAKS DOWN IN ADVANCE OF THE FRONT WEDS. MID-LEVEL
HIGH PRESSURE OVER THE SE STATES WILL RIDGE NEWD INTO THE MID-
ATLANTIC AS SFC HIGH BREAKS DOWN. SUBSIDENCE VISIBLE IN MODEL
SOUNDINGS COMBINED WITH LITTLE INSTABILITY AND THETA-E ADVECTION
WILL LIKELY INHIBIT PRECIP WEDS. WINDS VEER TO THE SOUTH WEDS
NIGHT AS SWLY FLOW ALOFT INCREASES. PRE-FRONTAL TROUGH FORECAST TO
DEVELOP OVER THE LOCAL AREA THURS...WHICH COMBINED WITH THETA-E
ADVECTION/INSTABILITY MAY PROVIDE THE FOCUS FOR AFTERNOON SHOWERS
AND THUNDERSTORMS. HOWEVER...LACK OF APPRECIABLE FORCING OUTSIDE
OF SMALL AMPLITUDE WAVES IN SWLY FLOW WILL LIKELY RESULT IN ONLY
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS. BEST COVERAGE
ANTICIPATED OVER THE PIEDMONT INTO CNTRL VA AND ALONG THE COAST TO
ACCOUNT FOR SEABREEZE BOUNDARIES. MODELS IN GOOD AGREEMENT WITH
DROPPING THE COLD FRONT INTO THE LOCAL AREA LATE THURS NIGHT INTO
FRI. THE UPPER WAVE DE-AMPLIFIES...WITH THE BEST DYNAMICS REMAINING
NORTH OF THE LOCAL AREA. DESPITE LACK OF DYNAMICS...WILL INCREASE
POPS TO CHANCE AS A WARM/MOIST AND MARGINALLY UNSTABLE AIR MASS IS
ANTICIPATED. OF COURSE...TIMING OF THE FRONT WILL IMPACT WHERE THE
BEST COVERAGE WILL BE ON FRIDAY AND HOW WARM TEMPS GET. EXPECT THE
FRONT TO CLEAR THE LOCAL AREA FRI NIGHT AS COOL CANADIAN HIGH
PRESSURE BUILDS IN FROM THE WEST. BEST CAA ARRIVES FRI NIGHT-SAT
AS HIGH PRESSURE REMAINS OVER THE OH VALLEY. THE RESULT WILL BE
PARTLY CLOUDY SKIES SAT WITH HIGHS IN THE UPPER 70S. WILL HOLD
ONTO SLIGHT CHANCE-CHANCE POPS ACROSS THE SE TO ACCOUNT FOR SLOWER
ECMWF AND PROXIMITY TO FRONT/MOISTURE.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
COLD FRONT HAS STALLED TO THE SOUTH OF THE AKQ FORECAST AREA.
MOIST NE FLOW WILL HELP LOCK IN THE MVFR CEILINGS FOR MOST OF THE
AREA THROUGH THE OVERNIGHT. STRENGTHENING LOW PRESSURE MOVING NE
ALONG THE STALLED BOUNDARY WILL OVERSPREAD RAIN S TO N STARTING
MONDAY MORNING. EXPECT PERIODS OF MVFR PRECIP WITH PERIODS OF IFR
CEILINGS MONDAY. AS THE SYSTEM MOVES NORTH...THE PRESSURE GRADIENT
WILL INCREASE CREATING 20KT WIND GUSTS AT KECG/KORF/KPHF/KSBY.
OUTLOOK...EXPECT PERIODS OF RAIN AND FLIGHT RESTRICTIONS THROUGH
WED AS THE SYSTEM SLOWLY MOVES OF THE COAST.
&&
.MARINE...
LATEST SFC ANALYSIS SFC COLD FRONT MOVING SOUTH ACROSS THE WATERS
THIS MORNING, WITH SOME SCT SHRAS ACROSS NORTHERN WATERS ALONG
PRE-FRONTAL TROUGH. FLOW IS E-NE ACROSS NORTHERN WATERS, WITH SW
FLOW FARTHER SOUTH ALONG CENTRAL/SOUTHERN COASTAL WATERS AND THE
LOWER CHES BAY. FRONT WILL DROP SOUTH ACROSS THE WATERS OVER THE
NEXT FEW HOURS WITH A BRIEF SURGE EXPECTED LATER THIS MORNING AS THE
BETTER CAA ARRIVES. LOOKING AT OBS IN THE UPPER CHES BAY, NOTING
GUSTS TO 18-22 KT OVER UPPER BAY, GENERALLY IN LINE WITH HRRR
DEPICTION. HRRR AND DOWNSCALE NAM DEPICTING A SHORT LIVED N-NE SURGE
WITH NE WINDS GUSTING TO MARGINAL/LOW END SCA IN THE BAY.
ACCORDINGLY, HV HOISTED A RELATIVELY SHORT DURATION SCA THROUGH
NOON.
FRONT WILL BECOME STALLED ALONG THE COAST LATE TONIGHT AND MONDAY
AS HIGH PRESSURE BUILDS OVER NEW ENGLAND. E-NELY FLOW CONTINUES
THROUGH THE PERIOD WITH HIGH PRESSURE REMAINING RIDGED OVER THE
WATERS THRU WEDNESDAY. MEANWHILE...LOW PRESSURE WILL DEVELOP ALONG
THE FRONT AND LIFT ALONG THE SE COAST AND OFF THE MID-ATLANTIC COAST
MON-WED. THIS WILL SERVE TO STRENGTHEN THE PRESSURE GRADIENT OVER
THE NRN WATERS...RESULTING IN NELY WINDS OF 20-25 KT OVER THE NRN
COASTAL WATERS DEVELOPING LATE TONIGHT INTO MON. SEAS WILL
RESPOND...BUILDING TO 4-6 FT NORTH OF CAPE CHARLES LIGHT. HV GONE
AHEAD WITH AN SCA OVER ATLANTIC COASTAL WATERS NORTH OF PARRAMORE
ISLAND FROM 6A MON-6A TUES. WINDS/SEAS REMAIN ELEVATED MON/MON NGT
BEFORE THE PRESSURE GRADIENT RELAXES. WEDGE BEGINS TO BREAK DOWN
WEDS AS A COLD FRONT APPROACHES FROM THE WEST. FLOW BECOMES SLY WED
NIGHT INTO THURS AND SWLY THURS AND FRI IN ADVANCE OF THE NEXT COLD
FRONT, WHICH IS FORECAST TO CROSS THE WATERS THURS NIGHT INTO FRI.
&&
.TIDES/COASTAL FLOODING...
DEVELOPING NE FLOW 15-20KT WILL DEVELOP LATER TODAY AND PERSIST
THROUGH TUESDAY NIGHT, AND WILL RESULT IN BUILDING TIDAL
ANOMALIES APPROACHING 1 TO 1.5 FT ABOVE NORMAL BY LATER MONDAY
THROUGH EARLY TUESDAY. NUISANCE TO LOW END MINOR TIDAL FLOODING
WILL BE POSSIBLE DURING THE MONDAY EVENING AND TUESDAY MORNING
HIGH TIDE CYCLES.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO MIDNIGHT EDT MONDAY
NIGHT FOR ANZ630>632-634-638.
SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
ANZ654-656.
SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 PM EDT TUESDAY FOR
ANZ650-652.
&&
$$
SYNOPSIS...ALB/TMG
NEAR TERM...ALB/TMG
SHORT TERM...ALB/TMG
LONG TERM...SAM
AVIATION...DAP
MARINE...SAM
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
348 PM EDT SUN SEP 7 2014
.SYNOPSIS...
A COLD FRONT HAS STALLED ALONG THE SOUTHEAST AND MID ATLANTIC
COASTS AS OF LATE THIS AFTERNOON AND IT WILL REMAIN NEARLY
STATIONARY THROUGH TUESDAY NIGHT. AN AREA OF LOW PRESSURE WILL
SLOWLY TRACK NORTHEAST ALONG THAT BOUNDARY FROM MONDAY AFTERNOON
THROUGH TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
COOLER...NOTICEABLY DRIER WX THIS AFTN. CDFNT HAS SETTLED WELL S
OF THE RGN...AND NNE WNDS (A LITTLE BIT GUSTY RIGHT AT THE CST)
PREVAIL OVR THE FA AS SFC HI PRES BUILDS INTO NEW ENG. OTHER THAN
AN ISOLD SHRA INVOF SE VA/NE NC...LARGE AREA OF RA CONFINED TO
JUST S OF THE ALBEMARLE SND MID AFTN. OTRW...PARTLY CLOUDY
N...MOSTLY CLOUDY S THROUGH THIS EVE.
SFC LO PRES WILL BEGIN TO DEVELOP INVOF INTERIOR SE CONUS LT
TNGT...AND BACKING OF MID LVL FLO WILL START TO PULL MOISTURE BACK
N. HAVE TRENDED A BIT SLOWER THAN THE MDLS W/ THE RETURN OF THE
MOISTURE LT TNGT. BY EARLY MON MRNG...WILL HAVE HIGHEST POPS
(60-80%) FAR SE VA/NE NC...TO 15-30% POPS ACRS NNW PORTIONS.
LO TEMPS IN THE L/M60S N...TO THE U60S TO ARND 70F FAR SE.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
AN UNSETTLED/WET PATTERN FOR THE FA THROUGH EARLY THIS WEEK. LO
PRES CONTG TO DEVELOP ALONG THE SE CONUS CST MON...THEN TRACKS
SLOLY TO THE NE ALG THE NC CSTL PLAIN AND EVENTUALLY OFF THE VA
CAPES LT TUE. THE COMBINATION OF INCRSG LO LVL MOISTURE FM THE
ATLC AND STRONG LIFT (ALONG/JUST N OF THE BOUNDARY AND ASSOCIATED
WITH THE MID LVL S/W)...WILL PRODUCE NUMEROUS SHOWERS OVR THE
AREA. HIGHEST POPS/CHC FOR HEAVIEST RAINFALL CONT TO BE OVR
ERN/SERN COUNTIES DURING THIS TIME. POPS DIMINISHING FM W TO E
BEGINNING LT TUE...AS THE LO MOVES OFF THE CST. WILL NOT RULE OUT
ISOLD THUNDER ESE AREAS...BUT WILL KEEP MENTION OUT OF FCST ATTM.
NE WNDS WILL BE GUSTY THROUGH THE TUE...TO POSSSIBLY 30-35 MPH AT
THE CST. HI TEMPS MON AND TUE RANGING THROUGH THE 70S. LO TEMPS
MON NGT MNLY FM 65 TO 70F.
GRADUAL IMPROVEMENT W/ DCRSG CLDNS WED. RETURN OF SUNSHINE XPCD TO
BOOST HI TEMPS BY CLOSER TO CLIMO NORMALS (ARND 80F AT THE
CST...M80S INLAND).
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MEDIUM RANGE GUIDANCE IN FAIRLY GOOD AGREEMENT THROUGH THE
PERIOD. THE MAIN FEATURE WILL BE A COLD FRONT SET TO CROSS THE
LOCAL AREA LATE IN THE WEEK...BRINGING COOLER/DRIER CONDITIONS TO
THE REGION BY NEXT WEEKEND.
UPPER FLOW WILL BE CHARACTERIZED BY AN AMPLIFYING TROUGH OVER THE
CNTRL CONUS...DOWNSTREAM OF AN ANOMALOUS RIDGE OVER THE WRN
PACIFIC AND GULF OF ALASKA. OVER THE LOCAL AREA...A LEADING
SHORTWAVE WILL FLATTEN THE UPPER FLOW BRIEFLY WEDS BEFORE SWLY
FLOW INCREASES IN ADVANCE OF THE APPROACHING UPPER TROUGH THURS-
FRI. AN ASSOCIATED COLD FRONT AND PARENT LOW WILL REACH THE GREAT
LAKES/OH VALLEY LATE WEDS INTO WEDS NIGHT. MEANWHILE...WEDGE OVER
THE LOCAL AREA BREAKS DOWN IN ADVANCE OF THE FRONT WEDS. MID-LEVEL
HIGH PRESSURE OVER THE SE STATES WILL RIDGE NEWD INTO THE MID-
ATLANTIC AS SFC HIGH BREAKS DOWN. SUBSIDENCE VISIBLE IN MODEL
SOUNDINGS COMBINED WITH LITTLE INSTABILITY AND THETA-E ADVECTION
WILL LIKELY INHIBIT PRECIP WEDS. WINDS VEER TO THE SOUTH WEDS
NIGHT AS SWLY FLOW ALOFT INCREASES. PRE-FRONTAL TROUGH FORECAST TO
DEVELOP OVER THE LOCAL AREA THURS...WHICH COMBINED WITH THETA-E
ADVECTION/INSTABILITY MAY PROVIDE THE FOCUS FOR AFTERNOON SHOWERS
AND THUNDERSTORMS. HOWEVER...LACK OF APPRECIABLE FORCING OUTSIDE
OF SMALL AMPLITUDE WAVES IN SWLY FLOW WILL LIKELY RESULT IN ONLY
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS. BEST COVERAGE
ANTICIPATED OVER THE PIEDMONT INTO CNTRL VA AND ALONG THE COAST TO
ACCOUNT FOR SEABREEZE BOUNDARIES. MODELS IN GOOD AGREEMENT WITH
DROPPING THE COLD FRONT INTO THE LOCAL AREA LATE THURS NIGHT INTO
FRI. THE UPPER WAVE DE-AMPLIFIES...WITH THE BEST DYNAMICS REMAINING
NORTH OF THE LOCAL AREA. DESPITE LACK OF DYNAMICS...WILL INCREASE
POPS TO CHANCE AS A WARM/MOIST AND MARGINALLY UNSTABLE AIR MASS IS
ANTICIPATED. OF COURSE...TIMING OF THE FRONT WILL IMPACT WHERE THE
BEST COVERAGE WILL BE ON FRIDAY AND HOW WARM TEMPS GET. EXPECT THE
FRONT TO CLEAR THE LOCAL AREA FRI NIGHT AS COOL CANADIAN HIGH
PRESSURE BUILDS IN FROM THE WEST. BEST CAA ARRIVES FRI NIGHT-SAT
AS HIGH PRESSURE REMAINS OVER THE OH VALLEY. THE RESULT WILL BE
PARTLY CLOUDY SKIES SAT WITH HIGHS IN THE UPPER 70S. WILL HOLD
ONTO SLIGHT CHANCE-CHANCE POPS ACROSS THE SE TO ACCOUNT FOR SLOWER
ECMWF AND PROXIMITY TO FRONT/MOISTURE.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
COLD FRONT HAS STALLED TO THE SOUTH OF THE AKQ FORECAST AREA.
MOIST NE FLOW WILL HELP LOCK IN THE MVFR CEILINGS FOR MOST OF THE
AREA THROUGH THE OVERNIGHT. STRENGTHENING LOW PRESSURE MOVING NE
ALONG THE STALLED BOUNDARY WILL OVERSPREAD RAIN S TO N STARTING
MONDAY MORNING. EXPECT PERIODS OF MVFR PRECIP WITH PERIODS OF IFR
CEILINGS MONDAY. AS THE SYSTEM MOVES NORTH...THE PRESSURE GRADIENT
WILL INCREASE CREATING 20KT WIND GUSTS AT KECG/KORF/KPHF/KSBY.
OUTLOOK...EXPECT PERIODS OF RAIN AND FLIGHT RESTRICTIONS THROUGH
WED AS THE SYSTEM SLOWLY MOVES OF THE COAST.
&&
.MARINE...
LATEST SFC ANALYSIS SFC COLD FRONT MOVING SOUTH ACROSS THE WATERS
THIS MORNING, WITH SOME SCT SHRAS ACROSS NORTHERN WATERS ALONG
PRE-FRONTAL TROUGH. FLOW IS E-NE ACROSS NORTHERN WATERS, WITH SW
FLOW FARTHER SOUTH ALONG CENTRAL/SOUTHERN COASTAL WATERS AND THE
LOWER CHES BAY. FRONT WILL DROP SOUTH ACROSS THE WATERS OVER THE
NEXT FEW HOURS WITH A BRIEF SURGE EXPECTED LATER THIS MORNING AS THE
BETTER CAA ARRIVES. LOOKING AT OBS IN THE UPPER CHES BAY, NOTING
GUSTS TO 18-22 KT OVER UPPER BAY, GENERALLY IN LINE WITH HRRR
DEPICTION. HRRR AND DOWNSCALE NAM DEPICTING A SHORT LIVED N-NE SURGE
WITH NE WINDS GUSTING TO MARGINAL/LOW END SCA IN THE BAY.
ACCORDINGLY, HV HOISTED A RELATIVELY SHORT DURATION SCA THROUGH
NOON.
FRONT WILL BECOME STALLED ALONG THE COAST LATE TONIGHT AND MONDAY
AS HIGH PRESSURE BUILDS OVER NEW ENGLAND. E-NELY FLOW CONTINUES
THROUGH THE PERIOD WITH HIGH PRESSURE REMAINING RIDGED OVER THE
WATERS THRU WEDNESDAY. MEANWHILE...LOW PRESSURE WILL DEVELOP ALONG
THE FRONT AND LIFT ALONG THE SE COAST AND OFF THE MID-ATLANTIC COAST
MON-WED. THIS WILL SERVE TO STRENGTHEN THE PRESSURE GRADIENT OVER
THE NRN WATERS...RESULTING IN NELY WINDS OF 20-25 KT OVER THE NRN
COASTAL WATERS DEVELOPING LATE TONIGHT INTO MON. SEAS WILL
RESPOND...BUILDING TO 4-6 FT NORTH OF CAPE CHARLES LIGHT. HV GONE
AHEAD WITH AN SCA OVER ATLANTIC COASTAL WATERS NORTH OF PARRAMORE
ISLAND FROM 6A MON-6A TUES. WINDS/SEAS REMAIN ELEVATED MON/MON NGT
BEFORE THE PRESSURE GRADIENT RELAXES. WEDGE BEGINS TO BREAK DOWN
WEDS AS A COLD FRONT APPROACHES FROM THE WEST. FLOW BECOMES SLY WED
NIGHT INTO THURS AND SWLY THURS AND FRI IN ADVANCE OF THE NEXT COLD
FRONT, WHICH IS FORECAST TO CROSS THE WATERS THURS NIGHT INTO FRI.
&&
.TIDES/COASTAL FLOODING...
DEVELOPING NE FLOW 15-20KT WILL DEVELOP LATER TODAY AND PERSIST
THROUGH TUESDAY NIGHT, AND WILL RESULT IN BUILDING TIDAL
ANOMALIES APPROACHING 1 TO 1.5 FT ABOVE NORMAL BY LATER MONDAY
THROUGH EARLY TUESDAY. NUISANCE TO LOW END MINOR TIDAL FLOODING
WILL BE POSSIBLE DURING THE MONDAY EVENING AND TUESDAY MORNING
HIGH TIDE CYCLES.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO MIDNIGHT EDT MONDAY
NIGHT FOR ANZ630>632-634-638.
SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
ANZ654-656.
SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 PM EDT TUESDAY FOR
ANZ650-652.
&&
$$
SYNOPSIS...ALB/TMG
NEAR TERM...ALB/TMG
SHORT TERM...ALB/TMG
LONG TERM...SAM
AVIATION...DAP
MARINE...SAM
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
230 PM EDT SUN SEP 7 2014
.SYNOPSIS...
A COLD FRONT WILL STALL ALONG THE SOUTHEAST AND MID ATLANTIC
COASTS LATE THIS AFTERNOON AND REMAIN NEARLY STATIONARY THROUGH
TUESDAY NIGHT...WITH AN AREA OF LOW PRESSURE MOVING NORTHEAST
ALONG THE BOUNDARY MONDAY AFTERNOON THROUGH TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CDFNT HAS SLIPPED S OF THE FA AS OF LT MRNG...W/ NNE WNDS (GUSTY
AT TIMES AT THE CST) CONTG TO USER IN COOLER/DRIER AIR FM THE N
AS SFC HI PRES BUILDS TOWARDS NEW ENG. LOWERED POPS FOR THE REST
OF THE DAY...TO 30-40% FAR SE VA/NE NC...THEN TAPER OFF TO AOB 10%
ACRS FAR NNW AREAS. HI TEMPS RANGING THROUGH THE 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
GOING WITH A BLEND OF THE LATEST GFS/ECMWF MODELS FOR TNGT THRU
TUE NGT...RESULTING IN AN UNSETTLED RATHER WET PATTERN FOR THE
REGION. LO PRES DEVELOPING ALNG THE SE CST TNGT INTO MON...WILL
LIFT NE ALNG THE STALLED FRNTL BOUNDARY AND OFF THE VA/NC CST MON
AFTN THRU TUE NGT. THE COMBINATION OF INCREASING LO LVL MOISTURE
FM THE ATLC AND STRNG LIFT (ALNG/JUST N OF THE BOUNDARY AND
ASSOCIATED WITH THE LO)...WILL PRODUCE NUMEROUS SHOWERS OVR THE
AREA...ESPLY LATER TNGT INTO TUE AFTN. HIGHEST POPS/CHC FOR
HEAVIEST RAINFALL WILL BE OVR ERN/SERN CNTIES DURING THIS TIME.
POPS WILL DIMINISH FM W TO E TUE AFTN THRU TUE NGT...AS THE LO
MOVES FARTHER OUT TO SEA. ISLTD THUNDER POSSIBLE ESE AREAS.
LO TEMPS TNGT RANGING THRU THE 60S TO NEAR 70. HI TEMPS ON MON AND
TUE IN THE MID 70S TO ARND 80.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MEDIUM RANGE GUIDANCE IN FAIRLY GOOD AGREEMENT THROUGH THE
PERIOD. THE MAIN FEATURE WILL BE A COLD FRONT SET TO CROSS THE
LOCAL AREA LATE IN THE WEEK...BRINGING COOLER/DRIER CONDITIONS TO
THE REGION BY NEXT WEEKEND.
UPPER FLOW WILL BE CHARACTERIZED BY AN AMPLIFYING TROUGH OVER THE
CNTRL CONUS...DOWNSTREAM OF AN ANOMALOUS RIDGE OVER THE WRN
PACIFIC AND GULF OF ALASKA. OVER THE LOCAL AREA...A LEADING
SHORTWAVE WILL FLATTEN THE UPPER FLOW BRIEFLY WEDS BEFORE SWLY
FLOW INCREASES IN ADVANCE OF THE APPROACHING UPPER TROUGH THURS-
FRI. AN ASSOCIATED COLD FRONT AND PARENT LOW WILL REACH THE GREAT
LAKES/OH VALLEY LATE WEDS INTO WEDS NIGHT. MEANWHILE...WEDGE OVER
THE LOCAL AREA BREAKS DOWN IN ADVANCE OF THE FRONT WEDS. MID-LEVEL
HIGH PRESSURE OVER THE SE STATES WILL RIDGE NEWD INTO THE MID-
ATLANTIC AS SFC HIGH BREAKS DOWN. SUBSIDENCE VISIBLE IN MODEL
SOUNDINGS COMBINED WITH LITTLE INSTABILITY AND THETA-E ADVECTION
WILL LIKELY INHIBIT PRECIP WEDS. WINDS VEER TO THE SOUTH WEDS
NIGHT AS SWLY FLOW ALOFT INCREASES. PRE-FRONTAL TROUGH FORECAST TO
DEVELOP OVER THE LOCAL AREA THURS...WHICH COMBINED WITH THETA-E
ADVECTION/INSTABILITY MAY PROVIDE THE FOCUS FOR AFTERNOON SHOWERS
AND THUNDERSTORMS. HOWEVER...LACK OF APPRECIABLE FORCING OUTSIDE
OF SMALL AMPLITUDE WAVES IN SWLY FLOW WILL LIKELY RESULT IN ONLY
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS. BEST COVERAGE
ANTICIPATED OVER THE PIEDMONT INTO CNTRL VA AND ALONG THE COAST TO
ACCOUNT FOR SEABREEZE BOUNDARIES. MODELS IN GOOD AGREEMENT WITH
DROPPING THE COLD FRONT INTO THE LOCAL AREA LATE THURS NIGHT INTO
FRI. THE UPPER WAVE DE-AMPLIFIES...WITH THE BEST DYNAMICS REMAINING
NORTH OF THE LOCAL AREA. DESPITE LACK OF DYNAMICS...WILL INCREASE
POPS TO CHANCE AS A WARM/MOIST AND MARGINALLY UNSTABLE AIR MASS IS
ANTICIPATED. OF COURSE...TIMING OF THE FRONT WILL IMPACT WHERE THE
BEST COVERAGE WILL BE ON FRIDAY AND HOW WARM TEMPS GET. EXPECT THE
FRONT TO CLEAR THE LOCAL AREA FRI NIGHT AS COOL CANADIAN HIGH
PRESSURE BUILDS IN FROM THE WEST. BEST CAA ARRIVES FRI NIGHT-SAT
AS HIGH PRESSURE REMAINS OVER THE OH VALLEY. THE RESULT WILL BE
PARTLY CLOUDY SKIES SAT WITH HIGHS IN THE UPPER 70S. WILL HOLD
ONTO SLIGHT CHANCE-CHANCE POPS ACROSS THE SE TO ACCOUNT FOR SLOWER
ECMWF AND PROXIMITY TO FRONT/MOISTURE.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
COLD FRONT HAS STALLED TO THE SOUTH OF THE AKQ FORECAST AREA.
MOIST NE FLOW WILL HELP LOCK IN THE MVFR CEILINGS FOR MOST OF THE
AREA THROUGH THE OVERNIGHT. STRENGTHENING LOW PRESSURE MOVING NE
ALONG THE STALLED BOUNDARY WILL OVERSPREAD RAIN S TO N STARTING
MONDAY MORNING. EXPECT PERIODS OF MVFR PRECIP WITH PERIODS OF IFR
CEILINGS MONDAY. AS THE SYSTEM MOVES NORTH...THE PRESSURE GRADIENT
WILL INCREASE CREATING 20KT WIND GUSTS AT KECG/KORF/KPHF/KSBY.
OUTLOOK...EXPECT PERIODS OF RAIN AND FLIGHT RESTRICTIONS THROUGH
WED AS THE SYSTEM SLOWLY MOVES OF THE COAST.
&&
.MARINE...
LATEST SFC ANALYSIS SFC COLD FRONT MOVING SOUTH ACROSS THE WATERS
THIS MORNING, WITH SOME SCT SHRAS ACROSS NORTHERN WATERS ALONG
PRE-FRONTAL TROUGH. FLOW IS E-NE ACROSS NORTHERN WATERS, WITH SW
FLOW FARTHER SOUTH ALONG CENTRAL/SOUTHERN COASTAL WATERS AND THE
LOWER CHES BAY. FRONT WILL DROP SOUTH ACROSS THE WATERS OVER THE
NEXT FEW HOURS WITH A BRIEF SURGE EXPECTED LATER THIS MORNING AS THE
BETTER CAA ARRIVES. LOOKING AT OBS IN THE UPPER CHES BAY, NOTING
GUSTS TO 18-22 KT OVER UPPER BAY, GENERALLY IN LINE WITH HRRR
DEPICTION. HRRR AND DOWNSCALE NAM DEPICTING A SHORT LIVED N-NE SURGE
WITH NE WINDS GUSTING TO MARGINAL/LOW END SCA IN THE BAY.
ACCORDINGLY, HV HOISTED A RELATIVELY SHORT DURATION SCA THROUGH
NOON.
FRONT WILL BECOME STALLED ALONG THE COAST LATE TONIGHT AND MONDAY
AS HIGH PRESSURE BUILDS OVER NEW ENGLAND. E-NELY FLOW CONTINUES
THROUGH THE PERIOD WITH HIGH PRESSURE REMAINING RIDGED OVER THE
WATERS THRU WEDNESDAY. MEANWHILE...LOW PRESSURE WILL DEVELOP ALONG
THE FRONT AND LIFT ALONG THE SE COAST AND OFF THE MID-ATLANTIC COAST
MON-WED. THIS WILL SERVE TO STRENGTHEN THE PRESSURE GRADIENT OVER
THE NRN WATERS...RESULTING IN NELY WINDS OF 20-25 KT OVER THE NRN
COASTAL WATERS DEVELOPING LATE TONIGHT INTO MON. SEAS WILL
RESPOND...BUILDING TO 4-6 FT NORTH OF CAPE CHARLES LIGHT. HV GONE
AHEAD WITH AN SCA OVER ATLANTIC COASTAL WATERS NORTH OF PARRAMORE
ISLAND FROM 6A MON-6A TUES. WINDS/SEAS REMAIN ELEVATED MON/MON NGT
BEFORE THE PRESSURE GRADIENT RELAXES. WEDGE BEGINS TO BREAK DOWN
WEDS AS A COLD FRONT APPROACHES FROM THE WEST. FLOW BECOMES SLY WED
NIGHT INTO THURS AND SWLY THURS AND FRI IN ADVANCE OF THE NEXT COLD
FRONT, WHICH IS FORECAST TO CROSS THE WATERS THURS NIGHT INTO FRI.
&&
.TIDES/COASTAL FLOODING...
DEVELOPING NE FLOW 15-20KT WILL DEVELOP LATER TODAY AND PERSIST
THROUGH TUESDAY NIGHT, AND WILL RESULT IN BUILDING TIDAL
ANOMALIES APPROACHING 1 TO 1.5 FT ABOVE NORMAL BY LATER MONDAY
THROUGH EARLY TUESDAY. NUISANCE TO LOW END MINOR TIDAL FLOODING
WILL BE POSSIBLE DURING THE MONDAY EVENING AND TUESDAY MORNING
HIGH TIDE CYCLES.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
ANZ650-652.
&&
$$
SYNOPSIS...ALB/TMG
NEAR TERM...ALB/TMG
SHORT TERM...ALB/TMG
LONG TERM...SAM
AVIATION...DAP
MARINE...MAM
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
359 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 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 141 PM EDT SUN SEP 7 2014
EXPECT VFR CONDITIONS THIS FCST PERIOD WITH A DRY SW FLOW ARND HI
PRES MOVING E THRU THE LOWER LKS. DAYTIME HEATING/MIXING WL ALLOW
FOR GUSTY WINDS TO 15-20 KT THIS AFTN AND LATE MON MORNING AT MAINLY
SAW AND IWD.
&&
.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...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
331 PM EDT SUN SEP 7 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM EDT SUN SEP 7 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR LKS BTWN AN UPR RDG OVER WRN NAMERICA AND A TROF IN THE E. A
SHRTWV EMBEDDED IN THIS WNW FLOW IS LOCATED NEAR JAMES BAY EARLY
THIS MRNG. A RIBBON OF MSTR/CLD COVER/SOME SHOWERS IS NOTED ALONG
ITS ATTENDANT COLD FNT STRECHING SWWD TOWARD NRN LK SUP AND A WEAK
LO PRES CENTER RUNNING EWD ALONG THE MN/ONTARIO BORDER. THE THICKER
CLDS AND SHOWERS JUST N OF LK SUP APPEAR TO FORCED BY AREA OF H85-5
QVECTOR CNVGC DEPICTED BY THE SHORT TERM MODELS. UPR MI IS DOMINATED
BY A LLVL W FLOW BTWN THE COLD FNT/SFC LO AND HI PRES MOVING INTO
THE MID MS RIVER VALLEY. THE UPSTREAM 00Z INL RAOB IS FAIRLY DRY
WITH 00Z H85/H7 DEWPT DEPRESSIONS RUNNING AT 7C/8C.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON HOW FAR S THE
AREA OF CLDS/SHOWERS JUST N OF LK SUP WL MOVE AND TEMPS FOR THIS
AFTN/TNGT.
TODAY...AS THE SHRTWV NEAR JAMES BAY MOVES ESEWD THRU QUEBEC
TODAY...ITS ATTENDANT COLD FNT IS PROGGED TO SHIFT S THRU NRN LK SUP
BEFORE STALLING NEAR THE KEWEENAW. SINCE THE AREA OF QVECTOR CNVGC
FORCING THE THICKER CLDS/SHOWERS NOW IN ONTARIO IS FCST TO SHIFT
ESEWD OVER NRN LK SUP AND N OF THE LAND CWA WITH THE DRY H85-7 W
FLOW DOMINATING...ALL THE SHORT TERM MODELS SHOW THE SHOWERS MOVING
NO FARTHER S THAN THE CNDN BORDER IN LK SUP BEFORE EXITING TO THE E
BY 18Z. ALTHOUGH SCT-BKN MID CLDS MAY BRUSH NRN UPR MI MAINLY THIS
MRNG...THERE SHOULD BE NO OTHER IMPACT. THE HI PRES NOW IN THE MID
MS RIVER VALLEY IS FCST TO SHIFT TO THE SE GREAT LKS BY 0Z MON. THE
WSW H925-85 FLOW THIS AFTN ARND THIS FEATURE IS FCST TO LIFT H85
TEMPS UP TO ARND 12C OVER THE CWA. THE FCST DEEP MIXED LYR/NEARLY
ADIABATIC SFC-H75 LAPSE RATES SHOWN ON FCST SDNGS WARRANTS HI TEMPS
TOWARD THE HI END OF GUIDANCE AND NEAR 80 OVER THE SCENTRAL AWAY FM
LK MODERATION. WEAKER GRADIENT NEAR LK SUP ASSOCIATED WITH LINGERING
LO PRES TROF SHOULD ALLOW FOR SOME LK BREEZE NEAR LK SUP AND SOME
LOCAL COOLING...BUT THE WSW 15-20KT H925 FLOW SHOULD LIMIT THE
INLAND PENETRATION OF THE LK BREEZE. MORE MODERATION IS LIKELY NEAR
LK MI E OF ESCANABA. ALTHOUGH THERE MAY BE SOME HI BASED CU...THE
AFTN SHOULD BE MOSUNNY WITH MIN RH DIPPING TOWARD 30 PCT AS DEWPTS
MIX OUT INTO THE LO-MID 40S AWAY FM LK INFLUENCE. THE DEEP MIXING
MAY ALLOW FOR SOME WIND GUSTS TO 15-20 MPH...BUT FIRE WX SHOULD NOT
BE A CONCERN GIVEN RECENT GENEROUS RAINFALL.
TNGT...UPR MI WL BE DOMINATED BY A STRENGTHENING SSW FLOW UNDER
TIGHTENING PRES GRADIENT BTWN THE HI PRES RETREATING TOWARD NEW
ENGLAND AND LO PRES TAKING SHAPE SW OF LK WINNIPEG. ALTHOUGH THE
AIRMASS WL BE DRY/SKIES MOCLR WITH PWAT DROPPING AS LO AS 0.50-0.75
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 OVER THE INTERIOR SCENTRAL AND E WHERE THE PRES
GRADIENT WL BE A BIT WEAKER/WINDS LIGHTER.
.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 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 141 PM EDT SUN SEP 7 2014
EXPECT VFR CONDITIONS THIS FCST PERIOD WITH A DRY SW FLOW ARND HI
PRES MOVING E THRU THE LOWER LKS. DAYTIME HEATING/MIXING WL ALLOW
FOR GUSTY WINDS TO 15-20 KT THIS AFTN AND LATE MON MORNING AT MAINLY
SAW AND IWD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 439 AM 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 WEAK TROUGH ACROSS LAKE SUPERIOR WILL SLOWLY DEEPEN
TUESDAY AFTERNOON...IN BETWEEN THE HUDSON BAY AND LOW PRESSURE
ORGANIZING ACROSS THE CENTRAL PLAINS. EXPECT THE CENTRAL PLAINS LOW
TO MOVE NE ACROSS THE UPPER GREAT LAKES WEDNESDAY AND WEDNESDAY
NIGHT...BEFORE EXITING INTO QUEBEC ON THURSDAY. AN EXTENDED PERIOD
OF N TO NW GALES WILL BE POSSIBLE WEDNESDAY INTO THURSDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...VOSS
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
152 PM EDT SUN SEP 7 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM EDT SUN SEP 7 2014
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR LKS BTWN AN UPR RDG OVER WRN NAMERICA AND A TROF IN THE E. A
SHRTWV EMBEDDED IN THIS WNW FLOW IS LOCATED NEAR JAMES BAY EARLY
THIS MRNG. A RIBBON OF MSTR/CLD COVER/SOME SHOWERS IS NOTED ALONG
ITS ATTENDANT COLD FNT STRECHING SWWD TOWARD NRN LK SUP AND A WEAK
LO PRES CENTER RUNNING EWD ALONG THE MN/ONTARIO BORDER. THE THICKER
CLDS AND SHOWERS JUST N OF LK SUP APPEAR TO FORCED BY AREA OF H85-5
QVECTOR CNVGC DEPICTED BY THE SHORT TERM MODELS. UPR MI IS DOMINATED
BY A LLVL W FLOW BTWN THE COLD FNT/SFC LO AND HI PRES MOVING INTO
THE MID MS RIVER VALLEY. THE UPSTREAM 00Z INL RAOB IS FAIRLY DRY
WITH 00Z H85/H7 DEWPT DEPRESSIONS RUNNING AT 7C/8C.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON HOW FAR S THE
AREA OF CLDS/SHOWERS JUST N OF LK SUP WL MOVE AND TEMPS FOR THIS
AFTN/TNGT.
TODAY...AS THE SHRTWV NEAR JAMES BAY MOVES ESEWD THRU QUEBEC
TODAY...ITS ATTENDANT COLD FNT IS PROGGED TO SHIFT S THRU NRN LK SUP
BEFORE STALLING NEAR THE KEWEENAW. SINCE THE AREA OF QVECTOR CNVGC
FORCING THE THICKER CLDS/SHOWERS NOW IN ONTARIO IS FCST TO SHIFT
ESEWD OVER NRN LK SUP AND N OF THE LAND CWA WITH THE DRY H85-7 W
FLOW DOMINATING...ALL THE SHORT TERM MODELS SHOW THE SHOWERS MOVING
NO FARTHER S THAN THE CNDN BORDER IN LK SUP BEFORE EXITING TO THE E
BY 18Z. ALTHOUGH SCT-BKN MID CLDS MAY BRUSH NRN UPR MI MAINLY THIS
MRNG...THERE SHOULD BE NO OTHER IMPACT. THE HI PRES NOW IN THE MID
MS RIVER VALLEY IS FCST TO SHIFT TO THE SE GREAT LKS BY 0Z MON. THE
WSW H925-85 FLOW THIS AFTN ARND THIS FEATURE IS FCST TO LIFT H85
TEMPS UP TO ARND 12C OVER THE CWA. THE FCST DEEP MIXED LYR/NEARLY
ADIABATIC SFC-H75 LAPSE RATES SHOWN ON FCST SDNGS WARRANTS HI TEMPS
TOWARD THE HI END OF GUIDANCE AND NEAR 80 OVER THE SCENTRAL AWAY FM
LK MODERATION. WEAKER GRADIENT NEAR LK SUP ASSOCIATED WITH LINGERING
LO PRES TROF SHOULD ALLOW FOR SOME LK BREEZE NEAR LK SUP AND SOME
LOCAL COOLING...BUT THE WSW 15-20KT H925 FLOW SHOULD LIMIT THE
INLAND PENETRATION OF THE LK BREEZE. MORE MODERATION IS LIKELY NEAR
LK MI E OF ESCANABA. ALTHOUGH THERE MAY BE SOME HI BASED CU...THE
AFTN SHOULD BE MOSUNNY WITH MIN RH DIPPING TOWARD 30 PCT AS DEWPTS
MIX OUT INTO THE LO-MID 40S AWAY FM LK INFLUENCE. THE DEEP MIXING
MAY ALLOW FOR SOME WIND GUSTS TO 15-20 MPH...BUT FIRE WX SHOULD NOT
BE A CONCERN GIVEN RECENT GENEROUS RAINFALL.
TNGT...UPR MI WL BE DOMINATED BY A STRENGTHENING SSW FLOW UNDER
TIGHTENING PRES GRADIENT BTWN THE HI PRES RETREATING TOWARD NEW
ENGLAND AND LO PRES TAKING SHAPE SW OF LK WINNIPEG. ALTHOUGH THE
AIRMASS WL BE DRY/SKIES MOCLR WITH PWAT DROPPING AS LO AS 0.50-0.75
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 OVER THE INTERIOR SCENTRAL AND E WHERE THE PRES
GRADIENT WL BE A BIT WEAKER/WINDS LIGHTER.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 439 AM EDT SUN SEP 7 2014
DRY WITH SLIGHTLY ABOVE TEMPERATURES THROUGH TUESDAY MORNING...THEN
BECOMING COOL AND WET THROUGH AT LEAST THE END OF THE WORK WEEK.
WILL CONTINUE TO EXPERIENCE WAA ON MONDAY...ON INCREASING S WINDS AS
UPPER MI REMAINS STUCK BETWEEN A LARGE AREA OF HIGH PRESSURE EXITING
THE NEW ENGLAND STATES...AND AN ELONGATED TROUGH SET UP FROM THE
CENTRAL PLAINS THROUGH ONTARIO AND HUDSON BAY. 850MB TEMPS WILL
AVERAGE AROUND 11C BY THE END OF THE DAY. S GUSTS NEAR 20KTS WILL BE
COMMON IN THE AFTERNOON. MAY END UP WITH SLIGHTLY WARMER TEMPS THAN
FCST ALONG THE SHORES OF LAKE SUPERIOR THANKS TO THE DOWNSLOPE FLOW.
DESPITE THE GFS AND ECMWF LIGHT QPF OUTPUTS MONDAY EVENING...HAVE
KEPT THE FCST DRY FOR NOW...ASSOCIATED WITH A 500MB SHORTWAVE AHEAD
OF THE SFC TROUGH SET UP ACROSS MN.
LOOK FOR THE SFC TROUGH TO SET UP ACROSS THE CWA TUESDAY AFTERNOON
INTO TUESDAY EVENING. KEPT TS POTENTIAL TO A MINIMUM TUESDAY-TUESDAY
EVENING OVER MAINLY W UPPER MI. THE BEST CHANCE OF OF WIDESPREAD
PRECIPITATION WILL BE EARLY WEDNESDAY MORNING THROUGH THURSDAY
MORNING AS THE CENTRAL PLAINS LOW OVER KS AT 00Z WEDNESDAY DRIFTS NE
INTO W WI BY 12Z WEDNESDAY AND LIKELY SWINGS ACROSS N LAKE MI WHILE
STRENGTHENING AT 00Z THURSDAY...BEFORE EXITING ACROSS N LAKE HURON
WEDNESDAY EVENING. THE INITIAL SHORTWAVE WILL CROSS UPPER MI
WEDNESDAY EVENING. QPF MAY NEAR AN INCH FROM 06Z WEDNESDAY THROUGH
12Z THURSDAY. BEHIND THE EXITING LOW MUCH COLDER AIR WILL BE ABLE TO
SINK IN. 850MB TEMPS OF -2 TO -4C WILL BE POISED ACROSS MUCH OF THE
S CANADIAN PRAIRIES WEDNESDAY EVENING. A SECONDARY 500MB LOW OVER S
SASKATCHEWAN/MANITOBA AT 06Z THURSDAY WILL SLOWLY TRACK TO UPPER MI
BY 12Z FRIDAY. THE COOLER CANADIAN AIR WILL BE ABLE TO SLIP IN. 50S
WILL BE COMMON FOR HIGH TEMPS THURSDAY THROUGH SATURDAY. THE LAST
TIME WE HAD 50S FOR HIGHS WAS JULY 15TH AND 8TH. IT/S A GOOD BET
THAT THEY WILL BE BACK FOR THURSDAY THROUGH SATURDAY. GIVEN THE
FAVORABLE UPSLOPE N-NW FLOW...EXPECT LINGERING SHOWERS NEAR LAKE
SUPERIOR THROUGH THE END OF THE WORK WEEK...WITH LAKE ENHANCED
CLOUDS AND SHOWERS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 141 PM EDT SUN SEP 7 2014
EXPECT VFR CONDITIONS THIS FCST PERIOD WITH A DRY SW FLOW ARND HI
PRES MOVING E THRU THE LOWER LKS. DAYTIME HEATING/MIXING WL ALLOW
FOR GUSTY WINDS TO 15-20 KT THIS AFTN AND LATE MON MORNING AT MAINLY
SAW AND IWD. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 439 AM 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 WEAK TROUGH ACROSS LAKE SUPERIOR WILL SLOWLY DEEPEN
TUESDAY AFTERNOON...IN BETWEEN THE HUDSON BAY AND LOW PRESSURE
ORGANIZING ACROSS THE CENTRAL PLAINS. EXPECT THE CENTRAL PLAINS LOW
TO MOVE NE ACROSS THE UPPER GREAT LAKES WEDNESDAY AND WEDNESDAY
NIGHT...BEFORE EXITING INTO QUEBEC ON THURSDAY. AN EXTENDED PERIOD
OF N TO NW GALES WILL BE POSSIBLE WEDNESDAY INTO THURSDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...VOSS
MARINE...KF
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
639 PM EDT SUN SEP 7 2014
.SYNOPSIS...
A COLD FRONT WILL STALL ACROSS EASTERN NORTH CAROLINA THIS EVENING.
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 630 PM SUNDAY...FRONTAL BOUNDARY CURRENTLY BISECTING THE CWA
FROM NORTHEAST TO SOUTHWEST. LATEST HRRR AND RUC SHOWS THE FRONT
SHOULD MOVE JUST SOUTH OF THE COAST OVER THE NEXT COUPLE OF HOURS.
AXIS OF HEAVY RAINFALL THIS AFTERNOON HAS BEEN OVER OUR NORTHERN
COUNTIES WHERE RADAR ESTIMATES UPWARDS OF 3 INCHES OF RAIN IN
PORTIONS OF PITT...MARTIN AND HYDE COUNTIES. ADDITIONAL SHOWERS
ARE APPROACHING THE SOUTHERN SECTIONS WHERE AXIS OF HIGHEST
PRECIPITABLE WATER AND LOW-LEVEL THETA-E ARE LOCATED. TRAINING OF
CELLS WILL LIKELY LEAD TO LOCALIZED FLOODING THROUGH THE NIGHT.
THINK COVERAGE OF CONVECTION SHOULD LESSEN SOMEWHAT WITH LOSS OF
HEATING OVER THE NEXT FEW HOURS. MADE JUST MINOR ADJUSTMENTS TO
THE FORECAST WITH TEMPS DROPPED A DEGREE OR TWO BASED ON CURRENT
READINGS AND POPS WERE ADJUSTED BASED ON RADAR COVERAGE.
LOW TEMPS TONIGHT MAINLY UPPER 60S INLAND TO LOW 70S COAST.
&&
.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 /22Z SUNDAY 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 640 PM SUNDAY...FRONTAL BOUNDARY IS SLOWLY WORKING ITS WAY
OFF THE SOUTH COAST AS OF 2230Z AND HRRR/RAP MODELS SHOW ITS
SHOULD BE OFFSHORE IN THE NEXT COUPLE OF HOURS. SPEEDS CONTINUE AT
15 KNOTS OR LESS WITH SEAS GENERALLY 2 TO 4 FEET. THE PRESSURE
GRADIENT WILL TIGHTEN SOUTH OF THE FRONT AS LOW PRESSURE RIDES NE
ALONG THE BNDRY LATER TONIGHT AND 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 MEMPHIS TN
1227 PM CDT SUN SEP 7 2014
.UPDATE...AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 1059 AM CDT SUN SEP 7 2014/
DISCUSSION...15Z SURFACE ANALYSIS PLACES A COLD FRONT ACROSS
SOUTHERN ALABAMA...MISSISSIPPI AND LOUISIANA WHILE A 1024 MB RIDGE
OF HIGH PRESSURE IS CENTERED OVER NORTHERN MISSOURI. AS OF 10 AM
CDT...MOSTLY CLOUDY/CLOUDY SKIES PREVAIL ACROSS AREAS SOUTH OF A
LINE FROM PARIS TENNESSEE BACK THROUGH WYNNE ARKANSAS...AND SUNNY
SKIES ELSEWHERE WITH TEMPERATURES IN THE 70S AT MOST LOCATIONS.
12Z WRF/GFS AND THE LATEST RUC STILL INDICATE A POSSIBILITY OF
ISOLATED RAIN SHOWERS AND PERHAPS A THUNDERSTORM MAINLY ACROSS
PORTIONS OF NORTH MISSISSIPPI THIS AFTERNOON. FORECAST OVERALL IS
IN GOOD SHAPE AND NO UPDATE ANTICIPATED AT THIS MOMENT.
CJC
DISCUSSION...
CURRENTLY...THE COLD FRONT HAS PUSHED WELL SOUTH OF THE AREA AND
COOLER...DRIER AIR IS FILTERING INTO THE MIDSOUTH. TEMPS RANGE
FROM THE MID 60S NORTH TO LOWER 70S ACROSS MONROE COUNTY.
DEWPOINTS IN THE UPPER 50S ARE BEGINNING TO SEEP ACROSS THE MO
BORDER. A BAND OF MID AND HIGH CLOUDS IS ALSO PUSHING ACROSS THE
AREA WITH A FEW SPRINKLES.
TODAY...A FEW SHOWERS/THUNDERSTORMS ARE POSSIBLE ACROSS NORTH
MISSISSIPPI WHERE SOME INSTABILITY REMAINS. THE NAM IS MOST
BULLISH ON THIS POSSIBILITY...ESPECIALLY ACROSS THE EXTREME
SOUTHEAST PART OF THE AREA WHERE DEWPOINTS ARE STILL AROUND 70.
OTRW HIGH PRESSURE ALONG WITH DRIER AND COOLER AIR WILL BUILD IN
WITH DECREASING CLOUDS. HIGHS WILL RANGE FROM THE LOWER 80S NORTH
TO MID 80S SOUTH.
TONIGHT THROUGH MONDAY NIGHT...HIGH PRESSURE AND MOSTLY CLEAR
SKIES WILL RESULT IN A PLEASANT NIGHT WITH LOWS IN THE 60S
AREA WIDE. PLENTY OF SUNSHINE EXPECTED ON MONDAY WITH TEMPS
IN THE MID TO UPPER 80S AND COMFORTABLE HUMIDITY LEVELS.
TUESDAY AND WEDNESDAY...SURFACE HIGH PRESSURE HEADS EAST AS UPPER
LEVEL HIGH PRESSURE NUDGES IN AND SOUTHERLY WINDS DEVELOP BRINGING
INCREASING HUMIDITY. TEMPS WILL WARM BACK ABOVE NORMAL...INTO THE
LOWER 90S...FOR PERHAPS WHAT WILL BE THE LAST GASP OF SUMMER. RAIN
CHANCES WILL BE MINIMAL DURING THIS TIME FRAME.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...A COLD FRONT WILL PUSH
THROUGH THE REGION WITH GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS.
SINCE THE 00Z MODELS ARE A LITTLE SLOWER BRINGING THE FRONT
INTO THE MIDSOUTH...ADJUSTED POPS DOWN ACROSS THE SOUTHERN HALF OF THE
AREA WEDNESDAY NIGHT. ALSO SINCE THE MODELS ARE MOVING THE FRONT
THROUGH SLOWER RAISED POPS ACROSS THE SOUTHERN HALF THURSDAY
NIGHT. PRECIP WATER VALUES ARE FORECAST TO BE ABOVE 2 INCHES ALONG
THE FRONT SO WILL NEED TO KEEP AN EYE ON THE POSSIBILITY OF
LOCALLY HEAVY RAIN. PUSHED TEMPS UP A FEW DEGREES ON THURSDAY
SINCE THE FRONT IS SLOWER.
FRIDAY AND SATURDAY...RAIN CHANCES WILL TAPER OFF ON FRIDAY AND
SKIES WILL BEGIN TO CLEAR AS VERY COOL HIGH PRESSURE STARTS TO
BUILD IN. HIGHS ON FRIDAY AND SATURDAY WILL ONLY BE IN THE 70S...TO
AROUND 80 ACROSS NE MS. LOWS FRIDAY NIGHT WILL DIP INTO THE 50S
AND WOULD NOT BE SURPRISED TO SEE SOME OF THE COOLER LOCATIONS IN
THE UPPER 40S IF THE 00Z GFS VERIFIES WELL.
SJM
&&
.AVIATION...18Z TAFS
VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24 HOURS. LOW MVFR CLOUDS
CURRENTLY AT MKL SHOULD DISSIPATE OVER THE NEXT HOUR OR TWO. THE
ONLY OTHER IMPEDIMENT TO AVIATION EXPECTED OVER THE NEXT 24 HOURS
IS PATCHY FOR AT TUP AND MKL AGAIN TONIGHT. LOW STRATUS IS ALSO
POSSIBLE...BUT LIGHT WINDS SHOULD HELP MINIMIZE THAT THREAT SO
WILL NOT INCLUDE ANY MVRE OR IFR DECKS AT THIS TIME. LIGHT
NORTHEAST WIND WILL PREVAIL AT ALL SITES.
30
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1210 PM CDT SUN SEP 7 2014
.AVIATION 18Z DISCUSSION...
COLD FRONT LOCATED TO OUR SOUTH AND CAA IS IN PLACE. UPPER LEVEL
PATTERN INDICATES A BROAD UPPER TROUGH WITH WEAK EASTWARD MOVING
IMPULSES. DYNAMICS ARE QUITE WEAK BUT JUST ENOUGH MOISTURE RESIDES
FOR A LIGHT SHOWER TO OCCUR HERE AND THERE PRIOR TO
00Z...PARTICULARLY ACROSS EASTERN AREAS OF MIDDLE TN.
BUT...OVERALL COVERAGE WILL BE LIMITED AND OTHER THAN THE CLOUD
COVER...MOISTURE WILL BE OMITTED FROM THE TAFS. TONIGHT...SOME FOG
WILL DEVELOP AS THE BKN CLOUD COVER TRENDS TOWARD SCT. VSBYS WILL
RETURN TO P6SM BY 13-14Z.
&&
.PREV DISCUSSION... /ISSUED 926 AM CDT SUN SEP 7 2014/
DISCUSSION...
FRONTAL BOUNDARY NOW POSITIONED TO THE SOUTH OF TN. UPPER PATTERN
FEATURES A RATHER WEAK BROAD TROUGH WITH A FEW IMPULSES RACING
EASTWARD ALONG THE WESTERLY FLOW. SAT IMAGERY DEPICTS A SWATH OF
CLOUDINESS MOVING ACROSS THE AREA WITH A FEW ISOLATED
SHOWERS...HERE AND THERE...AS WELL. MODELS KEEP THE CLOUDINESS IN
ACROSS THE AREA THROUGH THE DAY WITH PERHAPS SOME BREAKS IN THE
CLOUD COVER BY LATE AFTERNOON. HRRR NOT SHOWING MUCH SHOWER
DEVELOPMENT...BUT THE MODEL DATA DOES CARRY SOME QPF THROUGH THE
DAY...MAINLY EASTERN AREAS.
CURRENT FCST LOOKS OK BUT I WILL GO AHEAD AND LOWER TODAY`S HIGH
TEMPS. 18Z GRAPHICAL TEMPS SHOW MID 70S FOR BNA SO I WILL AIM FOR
HIGHS THAT WILL APPROACH 80 DEGREES. WITH THE CLOUD COVER AND
LIGHT NORTHERLY FLOW...THE CAA MAY WIN OUT AND TEMPS WILL STRUGGLE
TO WARM TODAY.
UPDATES OUT SHORTLY.
PREV DISCUSSION... /ISSUED 647 AM CDT SUN SEP 7 2014/
UPDATE...FOR 12Z AVIATION FORECASTS.
AVIATION...LOW-TO-MID LEVEL MOISTURE SLOW TO PULL OUT OF THE MID
STATE BEHIND YESTERDAY`S COLD FRONT. AS A RESULT, EXPECT IFR
AND MVFR CIGS AT CSV THROUGH 20Z AND MAINLY MVFR CIGS AT BNA THROUGH
20Z. MEANWHILE, BLV ENOUGH DRIER AIR HAS ALREADY FILTERED INTO THE
CKV AREA TO ALLOW FOR MAINLY VFR CONDITIONS THROUGH THE MORNING
AND THE UPCOMING AFTERNOON. BTWN 20Z/07 AND 06Z/08, BLV DRIER AIR
WILL HAVE PUSHED DEEP ENOUGH INTO THE MID STATE TO PRODUCE VFR
CONDITIONS AT ALL TERMINALS. AFTER 06Z, LOOK FOR PATCHY BR TO
DEVELOP AT CKV AND CSV, LIKELY PRODUCING MVFR VSBYS AT THOSE TWO
LOCATIONS AFTER 08Z.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
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.
&&
$$
Johnson/Daniels
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1239 PM CDT SUN SEP 7 2014
.UPDATE...
Clouds have begun to scatter over the southwest portion of the
CWA, mainly south of a Mertzon, to Eldorado, to Junction line. RAP
Mesoanalysis data indicates 100mb MLCAPE values on the order of
500-1000 J/kg along the I-10 corridor, but CINH remains an issue
for now. However, with additional insolation pushing temps into
the mid 80s, the cap should erode, resulting in scattered showers
and thunderstorms this afternoon and evening. This appears to have
been captured by both the GFS and NAM, in addition to the hi-res
CAMS.
The possibility of convection farther north cannot be ruled out,
but the highest PoPs were centered along I-10. Max temps were
nudged up a few degrees in the south and lowered across the
northwestern portion of the CWA where cloud cover will persist the
longest. Otherwise, changes to the inherited forecast were minor.
Johnson
&&
.AVIATION...
/18Z TAFS/
IFR conditions continue across portions of the CWA, namely along
the I-20 corridor, including KSWW and KABI, and in the KBBD area.
Ceilings will gradually improve at the forecast terminals over the
next few hours, with clouds scattering out south and west of a
KSJT to KJCT line. Generally VFR conditions are anticipated
areawide by late afternoon, with scattered showers (and a few
thunderstorms) possible this afternoon and evening along the I-10
corridor from KJCT, to KSOA, to KOZA. This was included in the
TAFs as VCSH for these sites. Winds will become light and variable
overnight, becoming south at 5-10 kts by mid-morning Monday.
&&
.PREV DISCUSSION... /ISSUED 653 AM CDT SUN SEP 7 2014/
AVIATION...
/12Z TAFS/
IFR conditions are occurring early this morning at the TAF sites
with ceilings between 500 ft and 1000 ft. Rain showers continue
to develop across various parts of West Central Texas, and
initially carrying a mention of SHRA or VCSH in the TAFs. The
coverage of showers should decrease between 12Z and 15Z, with
a possibility of scattered redevelopment through early this
evening. Although extensive cloud cover will persist through
early afternoon, expect a gradual improvement to MVFR conditions
as the ceilings slowly increase. VFR ceilings are expected by
late afternoon, and a decrease in cloud cover is anticipated this
evening and overnight. North-northeast winds this morning will
veer to the east by this evening, and to the southeast tonight.
Patchy fog development is possible late tonight, especially if
sufficient clearing occurs. But given the uncertainty at this
time and with several time groups already included in the TAF
package, decided to hold off at this point with adding fog and
visibility restrictions.
PREV DISCUSSION... /ISSUED 459 AM CDT SUN SEP 7 2014/
SHORT TERM...
(Today and Tonight)
Showers are occurring across our central and northern counties, in a
rather moist airmass north of a stalled frontal boundary. The most
noteworthy is a persistent east-west band of showers with moderate
to heavy rain, extending from just east of San Angelo to just south
of Brownwood. The HRRR and TTU WRF pick up on these showers to some
extent, with a trend of dissipation between 12Z and 15Z. May need to
extend the higher PoPs from the overnight period past 12Z this
morning. Will monitor radar trends and update if needed.
During the day today, have a possibility for scattered showers and a
few thunderstorms in the moist airmass. Considerable cloud cover
will hold through early afternoon, and then should have a decrease
in cloud cover from the west and southwest later in the afternoon.
The extent and duration of cloud cover is expected to have an effect
on temperatures today. Going with highs in the lower to mid 80s.
Have a lingering slight chance PoP early tonight for our central and
southern counties. Otherwise, a decrease in cloud cover is expected
overnight. Given the recent rainfall and a moist airmass, will have
a possibility for patchy fog development late tonight, depending on
the extent of clearing. Temperatures will cool to near dewpoint
values overnight with light (southeast) winds.
LONG TERM...
(Monday through next Sunday)
.A strong cold front will bring much cooler temperatures and
another chance of rainfall to the area by the end of the week...
South winds and much warmer temperatures return to the area Monday
through Wednesday, as a lee surface trough develops ahead of an
upper level trough moving east across the Rockies. Temperatures on
Monday will be near seasonal norms for this time of year, with
afternoon highs in the lower 90s. An isolated shower or thunderstorm
will be possible across far southeast counties during the
afternoon, otherwise dry conditions will prevail. Breezy south to
southwest winds and above normal temperatures return to the area
Tuesday and Wednesday with highs both days in the mid and upper
90s.
Big changes coming towards the end of the week as the aforementioned
upper trough tracks east across the Plains, sending a strong cold
front south across our area on Thursday. It will feel more like
fall behind the front Friday and Saturday with high temperatures
only in the middle/upper70s to lower 80s, with overnight lows in
the lower to middle 60s. We`ll also see another chance for showers
and thunderstorms along and behind the front Thursday into Friday.
Kept chance POPs in the forecast for now, but will likely need to
be raised further as model confidence increases. Below normal
temperatures continue for next Sunday but it will be a little
warmer with highs mainly in the middle 80s.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 82 68 92 73 95 / 30 10 10 5 5
San Angelo 83 68 92 71 95 / 40 20 10 5 5
Junction 86 69 91 71 94 / 50 20 10 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1232 PM CDT SUN SEP 7 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 240 AM CDT SUN SEP 7 2014
CURRENTLY AS OF 07Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED NORTHWEST FLOW FROM BRITISH COLUMBIA THROUGH THE GREAT LAKES
REGION...THOUGH A FAIRLY POTENT TROUGH WAS BEGINNING TO BUCK THIS
FLOW DROPPING SOUTH THROUGH BRITISH COLUMBIA. THE NORTHWEST FLOW HAS
HELPED PRODUCE A DRYING...SUBSIDENT REGIME OVER THE FORECAST
AREA...SEEN NICELY ON REGIONAL 00Z SOUNDINGS AS WELL AS PRECIPITABLE
WATER PLOTS SHOWING BETWEEN 0.5-0.75 INCHES OR 50-90 PERCENT OF
NORMAL. THIS DRY AIR HAS RESULTED IN BASICALLY CLEAR SKIES ACROSS
THE ENTIRE UPPER MIDWEST. SURFACE PATTERN FEATURES HIGH PRESSURE
CENTERED OVER THE MID MISSISSIPPI VALLEY WITH A WARM FRONT FROM
NORTHERN MN SOUTHWESTWARD INTO WYOMING. LIGHT SURFACE WINDS
ASSOCIATED WITH THE HIGH...CLEAR SKIES AND DRY AIR HAS ALLOWED FOR
TEMPERATURES TO DIP INTO THE MID 40S AT THE TYPICAL COLD SPOTS IN
CENTRAL WI. ABOVE THE SURFACE...HOWEVER...TEMPERATURES ARE WARMING
DUE TO A DOWNSLOPE WESTERLY FLOW FROM THE MOUNTAINS. 925MB TEMPS ARE
16-18C PER LATEST RAP ANALYSIS COMPARED TO AROUND 12C 24 HOURS AGO.
QUIET CONDITIONS LOOK TO CONTINUE FOR THE NEXT 24 HOURS AS THE
REGION REMAINS UNDER THE INFLUENCE OF THE SURFACE HIGH AND THE DRY
AIR ASSOCIATED WITH IT. STILL AT 12Z MONDAY...PRECIPITABLE WATER
PROGS ONLY SHOW VALUES OF 0.5-0.75 INCHES ACROSS THE REGION. IT
SHOULD BE NOTED THAT THE SURFACE HIGH DOES DRIFT OFF TO THE
EAST...WHICH ALLOWS FOR A RETURN FLOW TO DEVELOP ACROSS THE PLAINS.
THIS RETURN FLOW HELPS PULL A SURGE OF 1-1.25 INCH PRECIPITABLE
WATER THROUGH THE PLAINS INTO SOUTHWEST MN BY 12Z MONDAY.
ADDITIONALLY...A SHORTWAVE TRACKING THROUGH SOUTH DAKOTA TONIGHT
SHOULD RESULT IN SHOWERY CONVECTION BREAKING OUT AROUND THE SIOUX
FALLS AREA. SOME CIRRUS SPREADING OFF THIS PRECIPITATION LOOKS TO
SPREAD INTO THE AREA AFTER MIDNIGHT.
925MB TEMPS ARE PROGGED TO CHANGE VERY LITTLE TODAY FROM WHERE THEY
ARE NOW...HOLDING IN THAT 16-18C RANGE. STILL...THESE ARE 2-4C
WARMER THAN WHAT WE STARTED OFF WITH AT 12Z SATURDAY. THUS WITH
PLENTY OF SUN AGAIN HIGHS SHOULD END UP A COUPLE DEGREES WARMER. AN
INCREASING SOUTHWEST FLOW TONIGHT WILL HELP TEMPERATURES STAY A BIT
WARMER AS WELL...ESPECIALLY OVER THE HIGHER TERRAIN ALONG/WEST OF
THE MS RIVER WHERE A TIGHTER GRADIENT EXISTS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 240 AM CDT SUN SEP 7 2014
THE SHORTWAVE THAT COMES ACROSS SOUTH DAKOTA TONIGHT LOOKS TO SLIDE
ACROSS THE FORECAST AREA ON MONDAY...BRINGING THE SURGE OF SOMEWHAT
HIGHER PRECIPITABLE WATER INTO THE REGION AND THE ASSOCIATED SHOWERS
AS WELL. ITS HARD TO SAY HOW MUCH OF THE SHOWER ACTIVITY WILL MOVE
INTO THE AREA GIVEN THE INITIAL DRY AIRMASS IN PLACE. THIS IS
REFLECTED WELL IN THE 07.00Z NAM KEEPING THE FORECAST AREA DRY AND
SREF TRENDS THROUGH THE DAY DRYING THE PRECIPITATION UP. THE
TYPICALLY WETTER GFS SPREADS PRECIPITATION INTO THE WESTERN FORECAST
AREA...BUT SOUNDINGS ARE ALSO RELATIVELY DRY. FOR NOW...HAVE
CONFINED ANY PRECIPITATION CHANCES TO AFTER 18Z WEST OF THE MS RIVER
AND KEPT THE CHANCES AROUND 20. GIVEN THAT THE INSTABILITY AXIS
LOOKS TO STAY WEST OF I-35 DURING THE DAY...DO NOT HAVE ANY THUNDER
MENTIONED. A BETTER SHOT FOR PRECIPITATION EXISTS MONDAY NIGHT...
MAINLY ACROSS IOWA...AS ANOTHER WEAK SHORTWAVE MOVES THROUGH THAT
STATE AND THE NOSE OF A SURGE OF 850MB MOISTURE TRANSPORT POINTS IN
FOR A TIME. TEMPERATURES ON MONDAY LOOK SIMILAR TO TODAY GIVEN
SIMILAR 925MB TEMPS...POTENTIAL FOR SOME SUN AND A SOUTHERLY BREEZE
FOR MIXING. LOWS MONDAY NIGHT SHOULD BE NOTICEABLY WARMER WITH
HIGHER DEWPOINTS...CONTINUED SOUTHERLY BREEZE AND CLOUD COVER ALL
HELPING TO KEEP TEMPS UP.
THE MIDDLE OF THE WEEK CONTINUES TO BE THE ACTIVE PERIOD OF THE
FORECAST...CAUSED BY A VARIETY OF UPPER LEVEL FEATURES INFLUENCING
OR IMPACTING THE AREA. THE FIRST FEATURE IS THE CURRENT SHORTWAVE
TROUGH DROPPING THROUGH BRITISH COLUMBIA WHICH DIGS INTO THE HIGH
PLAINS TUESDAY NIGHT...SETTING UP SOUTHWEST UPPER FLOW AND A STRONG
INCREASE IN LOW LEVEL RETURN FLOW TOWARDS THE AREA. THE SECOND
FEATURE IS A COLLECTION OF SHORTWAVES THAT DEVELOP OFF THE COLORADO
MOUNTAINS ON TUESDAY...WHICH GET CAUGHT UP IN THE SOUTHWEST FLOW AND
LIFTED INTO THE FORECAST AREA TUESDAY NIGHT. THE 07.00Z NAM AND
ECMWF EVEN SUGGESTS THESE SHORTWAVES WILL PHASE WITH THE
AFOREMENTIONED TROUGH. THE THIRD FEATURE IS A PLUME OF EAST PACIFIC
TROPICAL MOISTURE SEEN EAST OF HURRICANE NORBERT ON WATER VAPOR...
WHICH LOOKS TO GET PULLED UP INTO THE FORECAST AREA ALSO ON TUESDAY
NIGHT.
AS THE AFOREMENTIONED DISCUSSION HIGHLIGHTS...TUESDAY NIGHT IS THE
CENTER POINT FOR PRECIPITATION. ALTHOUGH THERE ARE STILL SOME SLIGHT
MODEL DIFFERENCES...PARTICULARLY WITH TRACK AND TIMING OF THE
SURFACE SYSTEM...ALL MODELS REMAIN CONSISTENT IN SPREADING SHOWERS
AND EMBEDDED STORMS INTO THE REGION TUESDAY NIGHT. THEREFORE...HAVE
CONTINUED TO RAISE PRECIPITATION CHANCES. CAPE IS FAIRLY MEAGER
GIVEN LAPSE RATES NOT MUCH HIGHER THAN MOIST ADIABATIC...WHICH WILL
LIMIT SEVERE WEATHER. ON THE OTHER HAND...WARM CLOUD DEPTHS
APPROACHING 4-4.5 KM...PRECIPITABLE WATER CLIMBING TO 2 INCHES AND
STRONG 850MB MOISTURE TRANSPORT NOSING INTO THE AREA FAVOR HEAVY
RAINFALL POTENTIAL. LUCKILY THE FLOW LOOKS PROGRESSIVE ENOUGH TO
PREVENT FLOODING. WEDNESDAY IS TRICKY AS THE SYSTEM COULD BE HEADING
OFF TO THE EAST...ALLOWING DRIER AND SUBSIDENT AIR TO INFILTRATE THE
REGION. STILL A CONSENSUS EXISTS FOR SHOWERS AND STORMS TO BE AROUND
ACROSS WISCONSIN. IF THE SYSTEM WOULD SLOW UP...THERE WOULD BE AN
OPPORTUNITY FOR DESTABILIZATION AND SEVERE WEATHER GIVEN STRONG WIND
FIELD. HOWEVER...THIS SEEMS TO BE A VERY LOW PROBABILITY AT THIS
POINT. IN THE RAINFALL DEPARTMENT...LOOKS LIKE WE SHOULD PICK UP 1-2
INCHES FROM THIS SYSTEM.
IN THE WAKE OF THE SYSTEM...ITS ALL ABOUT THE COLD AIR. THE FIRST
SURGE COMES THROUGH WEDNESDAY NIGHT WITH 925MB TEMPS DROPPING TO 4-
6C BY 12Z THURSDAY. THIS CAUSES BOTH LOWS WEDNESDAY NIGHT AND HIGHS
ON THURSDAY TO TAKE A BIG HIT. EVEN COLDER AIR SURGES IN FOR
FRIDAY...RESULTING FROM AN UPPER TROUGH SWINGING ACROSS THE AREA.
THIS FEATURE SENDS 925MB TEMPS DOWN TO 2-4C BY 12Z FRI WITH ONLY
SLIGHT MODERATION DURING THE DAY. A BRISK NORTHWEST WIND COMBINED
WITH SOME POTENTIAL FOR SHOWERS...PARTICULARLY NORTH OF I-90
WEDNESDAY NIGHT AND THURSDAY NIGHT INTO FRIDAY...WILL REALLY MAKE IT
FEEL LIKE FALL. HIGH PRESSURE THEN LOOKS TO BUILD IN FOR FRIDAY
NIGHT...WHICH WOULD APPEAR TO STAND THE BEST CHANCE FOR FROST
FORMATION IN LIKELY THE TYPICAL COLD SPOTS. DRY CONDITIONS AND SLOW
MODERATION OF TEMPERATURES ARE EXPECTED ON SATURDAY AS THE
UPPER TROUGH EXISTS AND SUNSHINE HELPS WARM THE AIRMASS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1232 PM CDT SUN SEP 7 2014
SURFACE HIGH PRESSURE CENTERED ACROSS WEST CENTRAL ILLINOIS AT
07.1730Z WILL MOVE EASTWARD THIS EVENING AND OVERNIGHT...RESULTING
IN A STRONGER PRESSURE GRADIENT ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY. EXPECT SOUTHERLY WIND FROM 4 TO 8 KTS AT KRST/KLSE AFTER
SUNSET. A DRY NEAR SURFACE LAYER COMBINED WITH WINDS AT THE TOP OF
THE NOCTURNAL INVERSION OF AT LEAST 20 KTS SHOULD LIMIT FOG
DEVELOPMENT. MOSTLY SUNNY/CLEAR SKIES WILL PERSIST THROUGH 08.11Z
AFTER WHICH SOME MID-LEVEL CLOUDS WILL INCREASE FROM THE WEST
AHEAD OF THE NEXT DISTURBANCE ALOFT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION...ROGERS