Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/10/13
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
230 PM PDT SUN SEP 8 2013
.SYNOPSIS...
A SLIGHT COOLING TREND WILL OCCUR THROUGH MONDAY...BUT TEMPERATURES
WILL STILL BE ABOVE NORMAL. MORE SIGNIFICANT COOLING IS LIKELY
TUESDAY AND WEDNESDAY WITH TEMPERATURES DOWN TO NEAR OR SLIGHTLY
BELOW NORMAL LEVELS...THEN ANOTHER WARMING TREND IS EXPECTED FOR
LATE IN THE WEEK. THERE WILL BE A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS IN THE EASTERN MOUNTAINS AND THE ANTELOPE VALLEY
DURING THE AFTERNOON AND EVENING HOURS THROUGH WEDNESDAY.
&&
.SHORT TERM (TODAY-WED)...LONG WAVE RIDGE OVER THE WEST COAST AND
CENTERED OVER THE CENTRAL PORTION OF SOUTHERN OREGON AND ONE UPPER
LEVEL CYCLONIC CIRCULATION CENTERED OVER SOUTHERN CALIFORNIA AND A
SECOND AND THIRD OVER THE PACIFIC NORTHWEST WAS INITIALIZED
REASONABLY WELL THIS MORNING. THE LONG WAVE RIDGE WILL PERSIST
THROUGH THE PERIOD WHILE THE CYCLONIC CIRCULATIONS SHIFT EAST AND
SOUTH OVER THE AREA. HAVE INCLUDED A SLIGHT CHANCE OF THUNDERSTORMS
IN THE VICINITY OF VENTURA/KERN COUNTY LINE THIS EVENING. AND WILL
CONTINUE WITH A SLIGHT CHANCE OF THUNDERSTORMS OVER THE DESERT AND
MOUNTAINS IN LA COUNTY. PICTURES FROM SPACE VERIFIED GUIDANCE WHERE
MID LEVEL MOISTURE WAS CONSOLIDATING OVER THE NORTHERN PORTION OF
VENTURA COUNTY AT THIS TIME. RUC SOUNDING IN THE VICINITY OF THE
COUNTY LINE INDICATED A WEAKENING MID LEVEL CAP THROUGH THE
AFTERNOON AND SOUNDING WILL BECOME MODERATELY UNSTABLE. MOISTURE WAS
LIMITED EAST OF THE AREA TODAY AND EXPECT LITTLE PRECIPITATION.
THUNDERSTORMS AND
SHOWERS ARE EXPECTED TO MOVE WEST SOUTHWEST AROUND 10 KT IN VENTURA
COUNTY. RUC CONTINUES TO INDICATE A RELATIVELY STABLE SOUNDING OVER
SAN GABRIEL MOUNTAINS AND IF THUNDERSTORMS DEVELOP THEY WILL MOVE
WEST AS WELL. OTHERWISE CURRENT TEMPERATURES WERE 5 TO 10 DEGREES
COOLER THAN SATURDAY AT THIS TIME. A SLIGHTLY DEEPER MARINE LAYER IS
EXPECTED AND INFLUENCE TEMPERATURES PRODUCING A MIXED TREND MONDAY.
TEMPERATURES WILL DIFFER SLIGHTLY FROM TODAY AND WARM ALONG THE
CENTRAL COAST AND COOL SOUTH OF POINT CONCEPTION. INLAND
TEMPERATURES WILL LIKELY CONTINUE 3 TO 10 DEGREES ABOVE NORMAL. A
COOLING TREND BY 3 TO 6 DEGREES OVER THE ENTIRE AREA IS EXPECTED
TUESDAY...AN ONSHORE PRESSURE GRADIENT WILL STRENGTHEN AS A SURFACE
RIDGE BUILDS OVER THE BIGHT AND MARINE AIR WILL SHIFT INLAND. A
MIXED TEMPERATURE TREND IS EXPECTED WEDNESDAY AND TEMPERATURES WILL
WARM A COUPLE OF DEGREES OVER THE SOUTH HALF AND CONTINUE TO COOL A
COUPLE DEGREES OVER THE NORTH HALF. WILL CONTINUE WITH LOW POPS WITH
THUNDERSTORMS OVER THE MOUNTAINS EACH AFTERNOON THROUGH WEDNESDAY
WITHIN A RELATIVELY DRY AIR MASS.
.LONG TERM (THU-SUN)...THE LONG WAVE RIDGE IS EXPECTED TO WEAKEN AND
SHIFT EAST THROUGH THE PERIOD AND A BROAD LONG WAVE TROUGH WILL
DEVELOP UPSTREAM. WILL CONTINUE DRY THROUGH THE PERIOD. AS THE LONG
WAVE TROUGH OVER THE WESTERN PACIFIC TODAY SHIFTS EAST THROUGH THE
PERIOD A SURFACE FRONT IS EXPECTED TO MOVE OVER THE EASTERN PACIFIC
FRIDAY AND MOVE OVER NORTHERN CALIFORNIA SATURDAY. THE SOUTHERN
PORTION OF THE FRONT WILL LIKELY DISSIPATE NORTHWEST OF THE AREA
SATURDAY. LITTLE CHANGE IS EXPECTED WITH TEMPERATURES ON THURSDAY
THEN AS THE THE SURFACE FRONT OVER THE EASTERN PACIFIC APPROACHES
TEMPERATURES ARE EXPECTED TO WARM A FEW DEGREES OVER THE ENTIRE AREA
FRIDAY AND INLAND AREAS WILL LIKELY BE 5 TO 10 DEGREES ABOVE NORMAL.
A SLIGHT COOLING TREND IS THEN EXPECTED SATURDAY THROUGH SUNDAY
THOUGH TEMPERATURES WILL LIKELY CONTINUE 4 TO 8 DEGREES ABOVE
SEASONAL NORMAL.
&&
.AVIATION...08/1735Z...
OVERALL...MODERATE CONFIDENCE IN THE 18Z TAF PACKAGE. LATEST
SATELLITE SHOWS STRATUS DISSIPATING ACROSS COASTAL TAF SITES...WITH
CLEAR SKIES ACROSS INLAND TAF SITES. THROUGH THE EARLY
EVENING...WILL EXPECT VFR CONDS TO PREVAIL. OVERNIGHT...EXPECT
IFR/LIFR CONDS TO DEVELOP ACROSS COASTAL TAF SITES...WITH
LOW/MODERATE CONFIDENCE IN TIMING OF STRATUS RETURN.
KLAX...MODERATE CONFIDENCE IN 18Z TAF. THERE IS A 30% CHANCE OF IFR
CONDS BETWEEN 19Z AND 01Z. OVERNIGHT...CONFIDENCE HIGH IN RETURN OF
STRATUS...ALTHOUGH LOW CONFIDENCE IN TIMING OF RETURN.
KBUR...HIGH CONFIDENCE IN 18Z TAF.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX).
&&
$$
PUBLIC...30
AVIATION...KITTELL
SYNOPSIS...SWEET
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
907 PM MDT MON SEP 9 2013
.UPDATE...
ISSUED AT 907 PM MDT MON SEP 9 2013
IN THE SHORT TERM...ONE FEATURE STANDS OUT AND THAT IS THE MASS OF
HIGH CLOUD TOPS OVER SE UTAH AND SW COLORADO. LATEST SATELLITE
IMAGERY SHOW WARMING CLOUD TOPS...BUT CONVECTIVE CELLS STILL
CAPABLE OF GENERATING HEAVY SHOWERS WITH CORTEZ ASOS PICKING UP
FOUR TENTHS OF AN INCH IN A SHORT PERIOD OF TIME. THE HRRR SHOW
A BROAD AREA OF ONE HALF TO ONE INCH OF RAIN COVERING SW COLORADO
AND PORTIONS OF SE UTAH BY SUNRISE TUESDAY MORNING. THIS COULD BE
PROBLEMATIC AS SOILS MAY BECOME SATURATED WITH ENHANCED FLOWS IN
DRAINAGES OR NORMALLY DRY WASHES. THE ANTECEDENT CONDITIONS SETS
THE STAGE FOR WHAT IS EXPECTED ON TUESDAY.
TUESDAY...MODEL DATA SHOW A STRONG WAVE LIFTING NORTHWARD ACROSS
THE WESTERN SLOPE. THIS WAVE ENTERS SOUTHWEST COLORADO DURING THE
MORNING HOURS AND MOVES NORTHWARD DURING THE DAY...DEPARTING
NORTHWEST COLORADO LATE TUESDAY NIGHT. ASSOCIATED WITH THIS WAVE
IS DEEP LAYERED MOISTURE TRANSPORT...ISENTROPIC UPGLIDE...AND EVEN
SOME DYNAMICAL FORCING AS WELL TO ENHANCE LIFT. SPEED MAXIMA OF
50 KTS AT 300 MB WILL CREATE AN AREA OF UPPER LEVEL DIVERGENCE.
COMBINED WITH LOW LEVEL CONVERGENCE ASSOCIATED WITH THE BROAD AREA
OF SURFACE LOW PRESSURE...THE NET RESULT WILL BE DEEP CONVECTIVE
TOWERS WHERE CLOUD TOPS MAY BECOME COLDER THAN -60C.
RAINFALL AMOUNTS COULD EXCEED THOSE ON MONDAY...AND WITH SOILS AND
DRAINAGE AREAS BECOMING SATURATED (IF NOT ALREADY)...ADDITIONAL FLASH
FLOODING COULD RESULT. EXPANDED THE AREA OF POTENTIAL FLASH FLOODING
TO COVER THE REST OF THE WESTERN SLOPE THAT WAS NOT COVERED BY THE
WATCH EARLIER.
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 400 PM MDT MON SEP 9 2013
EXCEPTIONALLY WET PERIOD CONTINUES WITH WIDESPREAD PRECIPITATION
OCCURRING ACROSS BOTH CO AND UT WITH THIS TREND CONTINUING. WATER
VAPOR IMAGERY CURRENTLY SHOWING ANOMALOUS AMOUNTS OF MOISTURE
STREAMING UP FROM THE SOUTH WHILE A DEFORMATION AXIS HAS SET UP
OVER NEVADA INTO NRN UTAH. THIS AXIS IS ALLOWING MOISTURE AND
IMPULSES TO CONTINUE STREAMING INTO OUR AREA. LATEST GUIDANCE TO
INCLUDE THE NAM...RAP AND HRRR SHOW PRECIP CONTINUING THROUGH
TONIGHT AND THEN A RELATIVE LULL BEFORE ANOTHER WAVE CAUSES PRECIP
AGAIN DURING THE MORNING HOURS TOMORROW. WITH PLENTY OF RAIN
HAVING ALREADY FALLEN AND MORE ON THE WAY...EXTENDED THE FLASH
FLOOD WATCH THROUGH TUESDAY NIGHT AND ALSO ADDED THE UNCOMPAGHRE
AND ROAN/TAVAPUTS PLATEAUS SINCE THEY SAW THE BULK OF PRECIP
TODAY. SO FAR ONLY A FEW AREAS (PORTIONS OF ARCHES AND CANYONLANDS
NATIONAL PARK) HAVE REPORTED FLOODING DUE TO THE MAINLY STRATIFORM
NATURE OF THE PRECIP THOUGH A FEW EMBEDDED STORMS HAVE FIRED THIS
AFTERNOON. THE BIGGEST CONCERN HAS BEEN...AND CONTINUES TO
BE...SERN UTAH DUE TO THE SLOT CANYON AND DESERT TERRAIN. LOTS OF
CLOUDS HAVE INHIBITED CONVECTION SO FAR TODAY THOUGH VIS IMAGERY
DOES SHOW SOME BREAKS STARTING TO FORM. WILL ALERT NEXT SHIFTS TO
KEEP AN EYE ON AREA. MOST TEMPS ARE RUNNING ABOUT 5 TO 10 DEGREES
COOLER THAN NORMAL DUE TO RAINFALL AND CLOUDS.
OVERNIGHT...SOME MODELS DEPICT MORE STEADY PRECIP TO
CONTINUE...ESPECIALLY FOR THE ABAJOS...LA SALS AND
UNCOMPAGHRE/ROAN/TAVAPUTS PLATEAUS. OTHER MODELS SHOW MORE OF A
LULL. KEPT PRECIP IN FORECAST AS MOISTURE WILL CONTINUE TO STREAM
OVERHEAD AND ANY WEAK DISTURBANCE/IMPULSE WILL CREATE SHOWERS. FOR
TOMORROW THOUGH...MORE IMPULSES WILL CONTINUE TO MOVE OVER THE CWA
WITH WHAT APPEARS TO BE A SIGNIFICANT IMPULSE MOVING INTO THE 4
CORNERS BY 7AM AND THEN SPREADING NWRD BY NOON. FOR TUESDAY
THEN...ANOTHER DAY LIKE TODAY...CLOUDS...RAIN...COOL TEMPERATURES
WITH INCREASED FLOODING CONCERNS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 400 PM MDT MON SEP 9 2013
THE MAIN STORM TRACK WITH THE STRONGER WESTERLIES WILL REMAIN WELL
TO THE NORTH OF THE INTERMOUNTAIN WEST THROUGH THIS EXTENDED PERIOD.
BY WEDNESDAY STRONG TROUGHING INTO THE GREAT LAKES REGION AND INTO
THE GULF OF ALASKA LEAVES AN AMPLIFIED RIDGE OVER THE NORTHERN US
AND CANADIAN ROCKIES. THIS NORTHERN RIDGE WILL LEAD TO A REX PATTERN
DUE TO AN AREA OF LOW PRESSURE THAT GETS CUT OFF....AND WILL WOBBLE
AROUND THE GREAT BASIN. THIS LOW WILL BE HELD FROM MOVING WEST TO
EAST BY THE SUBTROPICAL HIGH OVER THE SOUTHEAST STATES AND PACIFIC
HIGH PRESSURE BUILDING TOWARD THE WEST COAST. THIS PATTERN WILL BE
STATIC THROUGH AT LEAST THURSDAY AFTER WHICH MEDIUM RANGE MODELS
SWING SOME STRONGER ENERGY INTO WESTERN CANADA...BREAKING THE REX
BLOCK...AND ALLOWING THE GREAT BASIN LOW TO TO BEGIN TO LIFT
NORTHWARD. HOWEVER THERE ARE MODEL CONFLICTS WITH HOW THIS LOW
INTERACTS WITH THE ENERGY BREAKING DOWN THE RIDGE BY LATE IN THE
FORECAST...LEAVING VERY LOW CONFIDENCE IN THE LATTER PERIODS SO
BLENDED MODELS GENERALLY FOLLOWED.
SO TO FOCUS ON THE PERIOD WHEN THE UPPER LOW IS CUTOFF IN THE GREAT
BASIN WEDNESDAY AND THURSDAY. THE MODELS ARE SIMILAR IN LIFTING ONE
LOBE OF STRONGER ENERGY NORTHWARD OUT OF OUR CWA ON
WEDNESDAY...WHILE ROTATING ANOTHER STRONG PIECE ACROSS UTAH ON
THURSDAY. SUBSIDENCE BEHIND THE FIRST WAVE WILL GENERALLY BRING
SOMEWHAT OF A DOWNTURN TO THE PRECIPITATION FOR WEDNESDAY...WITH THE
FAMILIAR PATTERN OF STORMS FOCUSING ON THE TERRAIN BY EARLY
AFTERNOON BEFORE SPREADING INTO THE VALLEYS. ASCENT WILL BEGIN TO
INCREASE SIGNIFICANTLY ON THURSDAY AFTERNOON OVER OUR CWA THURSDAY
WITH THE DYNAMIC TROP DIPPING DOWN TOWARD 400MB WHICH SHOULD ENHANCE
THE INSTABILITY AND BRING AN UPTURN TO STORMS FOR THURSDAY. THE
STRONGER MONSOON PLUME WILL GET DISRUPTED BUT STILL PLENTY OF
MOISTURE AROUND FOR MAKING STORMS. THE DRY CONVEYOR BELT ASSOCIATED
WITH THE PV LOBE MAY ALSO LEAD TO SOME STRONGER STORM DEVELOPMENT.
FROM FRIDAY ONWARD THE LOW WILL HAVE LIFTED NORTH AND EAST OF OUR
AREA BUT A RESIDUAL TROF REMAINS IN PLACE. MOISTURE WILL BEGIN TO
WANE BUT PWATS STILL HOVER AROUND OR JUST ABOVE NORMAL FOR MID
SEPTEMBER AND THIS WILL KEEP A THREAT OF SHOWERS AND THUNDERSTORMS
GOING INTO THE LATE PERIODS. TEMPERATURES THROUGH THE EXTENDED
PERIOD LOOK TO HOVER NEAR THE SEASONAL NORMALS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 400 PM MDT MON SEP 9 2013
RAINFALL CONTINUES THIS AFTERNOON AND FOR MUCH OF THE NEXT 24
HOURS. MVFR AND OCCNL IFR IS EXPECTED THROUGH TOMORROW MORNING
WITH LOW CIGS AND VIS UNDER THE STRONGER SHOWERS AND STORMS THAT
FORM. FOG WILL ALSO BE A CONCERN ESPECIALLY IN THE MORNING DUE TO
AMOUNT OF MOISTURE IN THE AIR. ALL TAF SITES ARE UNDER THE GUN FOR
PRECIP...LOW CLOUDS AND VISIBILITIES THROUGH 00Z TOMORROW.
MOUNTAIN OBSCURATIONS CAN BE EXPECTED OVER ALL HIGHER TERRAIN.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR COZ003-017-020-021.
FLASH FLOOD WATCH FROM TUESDAY MORNING THROUGH TUESDAY EVENING
FOR COZ001-002-004>014-018-019-022-023.
UT...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR UTZ022-025-027>029.
&&
$$
UPDATE...PF
SHORT TERM...TGR
LONG TERM...15
AVIATION...TGR
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
406 AM MDT SUN SEP 8 2013
.SHORT TERM...THE STUBBORN UPPER LEVEL RIDGE WILL FINALLY BEGIN TO
SHIFT EASTWARD AS AN UPPER LEVEL TROUGH MOVES INTO THE NRN
ROCKIES BY TONIGHT. INFLUX OF SUBTROPICAL MOISTURE WILL REMAIN IN
THE MTNS AND ACROSS THE NRN FOOTHILLS THRU TONIGHT WITH SCT TSTMS
DEVELOPING BY AFTN. ELSEWHERE OUTFLOW BOUNDARIES FM CONVECTION
OVER THE HIGHER TERRAIN MAY SWEEP ACROSS THE FRONT RANGE BY LATE
AFTN INTO THE EARLY EVENING HOURS ALLOWING FOR SOME ISOLD TO WDLY
SCT HIGHER BASED STORMS TO DVLP. AS FOR HIGHS ONE MORE AFTN FOR 90
DEGREE PLUS READINGS OVER NERN CO. RECORD AT DENVER IS 94 DEGREES
WHICH COULD BE TIED OR BKN DEPENDING ON TIMING OF MID LVL CLOUD
COVER THIS AFTN.
FOR TONIGHT EXPECT SOME LINGERING SHOWERS AND A FEW STORMS IN THE
MTNS OVERNIGHT AS SUBTROPICAL MOISTURE FEED CONTINUES. OVER NERN CO
ISOLD-WDLY SCT TSTM ACTIVITY ALONG THE FRONT RANGE SHOULD END BEFORE
06Z. BY LATE TONIGHT A COOL FRONT WILL BEGIN TO MOVE SOUTH INTO
NERN CO WITH NLY WINDS DEVELOPING TOWARDS SUNRISE.
.LONG TERM...MODELS CONTINUE TO SHOW A SHIFT IN THE UPPER FLOW
PATTERN THAT WILL BRING A FEW DAYS OF RAINFALL TO PARTS OF NORTH-
CENTRAL AND NORTHEAST COLORADO. THE UPPER RIDGE THAT DOMINATED
COLORADO WEATHER THIS PAST WEEK WITH RECORD BREAKING TEMPERATURES
WILL CONTINUE MOVING EASTWARD AND WEAKENING FOR THE NEXT 48-60
HOURS AS AN UPPER TROUGH MOVES OVER THE NORTHERN ROCKIES AND TO
THE CANADIAN PRARIES. OVER COLORADO...THE FLOW OF MID-LEVEL
SUBTROPICAL MOISTURE IS EXPECTED TO STRENGTHEN. THIS WILL LEAD TO
AN INCREASE IN SHOWER ACTIVITY OVER THE MOUNTAINS WHICH WILL ALSO
EXTEND ONTO THE NORTHEAST COLORADO PLAINS. TUESDAY LOOKS LIKE IT
IS GOING TO BE THE COOLEST DAY OF THE WEEK DUE TO A SURGE OF COOL
AIR COMING INTO THE STATE FROM THE NORTH MONDAY NIGHT. THE AIRMASS
MAY ALSO BE COOLED SOME BY THE RAINFALL FROM MONDAY NIGHT. SHOWER
ACTIVITY MONDAY EVENING IS GOING TO BE ENHANCED BY A WEAK UPPER
LEVEL JET ASSOCIATED WITH THE NORTHERN ROCKIES TROUGH THAT WILL
BE IN PLACE OVER WYOMING. EACH OF THE MODELS INDICATE THAT SHOWERS
OVER THE FORECAST AREA COULD LAST THROUGH MOST OF MONDAY NIGHT.
ONCE THE UPPER LEVEL PATTERN SHIFTS TO MOIST AND SOUTH-
SOUTHWESTERLY ON MONDAY...IT WILL REMAIN IN PLACE MOST OF THE
WEEK. SHOWERS ARE EXPECTED TO KEEP GENERATING EACH DAY AS
SUBTROPICAL MOISTURE CONTINUES MOVING INTO THE STATE. AT THIS TIME
IT IS DIFFICULT TO TELL IF ANY OF THE DAYS WILL HAVE PARTICULARLY
HEAVY RAINFALL...SO WILL JUST KEEP AN EYE ON THE MODEL RUNS AS
THEY KEEP COMING IN. MODEL SOUNDINGS SHOW THAT PRECIPITABLE WATER
VALUES WILL INITIALLY RISE TO THE 1.00 TO 1.10 INCH RANGE WHICH IS
NOT THAT ABNORMAL FOR THE LATE SUMMER. THE FORECAST PACKAGE DID
NOT NEED THAT MUCH ADJUSTMENT THIS TIME AROUND.
&&
.AVIATION...DRAINAGE WINDS EARLY THIS MORNING MAY BECOME LIGHT AND
VARIABLE BY 14Z AND LINGER THRU 18Z. BY EARLY AFTN WINDS WILL
BECOME MORE SSE. LAST FEW RUNS OF THE RAP SHOWS A RATHER STG
OUTFLOW BNDRY COMING OUT OF THE FOOTHILLS AND ACROSS DIA IN THE
00Z-01Z TIME PERIOD ALONG WITH SOME ISOLD HIGHER BASED STORMS SO
WILL MENTION VCTS WITH A TEMPO GROUP FOR GUSTY OUTFLOW WINDS FOR A
FEW HOURS. AFTER CONVECTIVE BOUNDARIES MOVE ACROSS WINDS SHOULD
GRADUALLY SHIFT BACK TO MORE SSW BY 06Z. OVERNIGHT LOOKS LIKE A
A SHIFT TO NLY WINDS WILL OCCUR IN THE 12Z-15Z TIMEFRAME ON MON AS
A COOL FRONT MOVE ACROSS. AT THIS TIME NO LOW CLOUDS ARE EXPECTED
WITH THIS FEATURE.
&&
.HYDROLOGY...WILL SEE SCATTERED STORMS IN THE MTNS AND NRN
FOOTHILLS THIS AFTN ALTHOUGH THE FLOW ALOFT WILL BE A BIT STRONGER
SO THEY SHOULD MOVE ALONG. RAINFALL AMOUNTS WILL BE LESS THAN ONE
HALF INCH HOWEVER UP TO AN INCH COULD OCCUR WITH ANY STRONGER
STORM.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....DANKERS
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
355 AM MDT SUN SEP 8 2013
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 353 AM MDT SUN SEP 8 2013
PATTERN SHIFT UNDERWAY ACROSS THE WESTERN U.S. AS THE CLOSED LOW
OVER THE PACNW FINALLY KICKS EAST. THIS WILL ALLOW THE DEEP
MONSOONAL PLUME THAT HAS BEEN PARKED JUST TO OUR WEST...TO SHIFT
EAST AND SOUTH OVER OUR AREA FOR THE NEXT FEW DAYS. SEVERAL
EMBEDDED WAVES WITHIN THE FLOW WILL ENHANCE CONVECTION AND TEAM
WITH THE NUMEROUS OUTFLOW BOUNDARIES ROAMING THE FORECAST AREA TO
TRIGGER AN INCREASE IN CONVECTION THIS AFTERNOON. POTENTIAL FOR
HEAVY RAIN DEFINITELY ON THE INCREASE WITH MODEL PRECIPITABLE
WATER FORECAST JUMPING TO OVER AN INCH THIS AFTERNOON AND PEAK
AROUND 1.40 INCHES BY EARLY MONDAY MORNING. EXPECT ENOUGH BREAKS
IN CLOUD COVER TODAY TO ALLOW A FEW STRONGER STORMS TO FIRE WITH
THE HRRR DEVELOPING DEEPER CONVECTION AFTER 18Z ACROSS SOUTHEAST
UTAH. STORM MOTION WILL REMAIN FAIRLY SLOW AND POTENTIAL FOR SOME
TRAINING EXISTS. FOCUS OF ATTENTION THROUGH THIS AFTERNOON WILL BE
THE CANYON COUNTRY IN SOUTHEAST UTAH AND CLOSE TO LAKE POWELL IN
SAN JUAN COUNTY UTAH...ALTHOUGH ANY STORMS THAT FIRE WILL BE
CAPABLE OF PRODUCING HEAVY RAINFALL. CONFIDENCE INCREASING THAT
WE WILL BE HAVING SOME FLASH FLOOD PROBLEMS BEGINNING THIS
AFTERNOON AND CONTINUING THROUGH MONDAY EVENING. AS A
RESULT...WILL BE ISSUING A FLASH FLOOD WATCH FOR EAST CENTRAL AND
SOUTHEAST UTAH AND PORTIONS OF SOUTHWEST COLORADO...MAINLY FOR THE
BEDROCK AND SLICK ROCK AREAS NORTH OF CORTEZ AND SOUTH OF
GATEWAY. WITH CLOUD COVER AND GREATER SFC MOISTURE IN
PLACE...TEMPS DROP AT LEAST 5 DEGREES ACROSS THE BOARD...BRINGING
AN END TO THE RECENT STRETCH OF 90 PLUS DAYS IN GRAND JUNCTION.
A WET WEEK IS IN STORE FOR THE REGION WITH THE EASTERN UTAH AND
THE SOUTHERN SLOPES OF OF THE SOUTHERN AND CENTRAL MOUNTAINS
FAVORED FOR HEAVY RAINFALL. MODELS REMAIN IN GOOD AGREEMENT.
SUNDAY NIGHT INTO MONDAY THE PACIFIC UPPER LOW TRACKS THROUGH THE
NORTHERN ROCKIES AND ONTO THE NORTHERN PLAINS LEAVING A VERTICALLY
STACKED TROUGH IN THE GREAT BASIN CENTERED OVER LAS VEGAS. THIS
PRODUCES ENHANCES S-SW MOIST AND PERTURBED FLOW INTO EASTERN UTAH.
PRECIPITABLE WATER SURGES TO 1.4 INCHES IN SE UTAH TO OVER AN INCH
NORTH OF CRAIG. STORM MOTION IS TO THE NE AT 20KTS WHICH WILL
LIMIT RAINFALL FROM ANY ONE STORM BUT TRAINING WILL QUICKLY ADD
UP. DIVERGENCE ALOFT IN THE RIGHT ENTRANCE REGION OF A WEAK 40KT
JET OVER NE UTAH- FAR NW CO WILL ENHANCE SHOWERS THERE. CLOUDS
AND SHOWERS WILL DROP MONDAY TEMPERATURES BELOW NORMAL FOR THE
FIRST TIME THIS MONTH.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 353 AM MDT SUN SEP 8 2013
SOME CHANGES IN STORE IN THE PATTERN THROUGH TUESDAY NIGHT BUT
WIDESPREAD SHOWERS AND STORMS WILL CONTINUE. EAST LOW LEVEL FLOW
SETS UP MONDAY NIGHT THAT MAY LIMIT RAINFALL AMOUNTS. BUT WEAK
COLD ADVECTION ALOFT MAY PRODUCE ENOUGH FORCING TO OVERCOME THIS.
MODELS ARE NOW PRODUCING SOME LIGHT SNOWFALL ABOVE TIMBERLINE
ESPECIALLY MONDAY NIGHT. DIVERGENCE ALOFT REMAINS OVER NE UTAH.
TUESDAY THE REMNANTS OF WHAT WAS TS LORENA...CURRENTLY ALONG THE
SOUTHERN BAJA... WILL BE PULLED INTO FOUR CORNERS ENHANCING
ALREADY DEEP MOISTURE. STORM MOTION OF TO THE NORTH AT 15-20 MPH
WILL AGAIN MAKE FLOODING DIFFICULT FROM ANY ONE STORM...BUT MUD
FLOWS WILL THREATEN FROM TWO DAYS OF HEAVY RAIN ESPECIALLY ALONG
SOUTH FACING SLOPES. SCATTERED TO WIDESPREAD STORMS CONTINUE INTO
WEDNESDAY MORNING.
MOIST AND UNSETTLED CONDITIONS REMAIN IN PLACE THROUGH THURSDAY AS
REMNANTS OF TROPICAL STORM LORENA CONTINUE TO PUSH NORTHEAST THROUGH
THE FORECAST AREA. THIS WILL KEEP THE POTENTIAL FOR HEAVY RAIN IN
THE FORECAST. SUBTLE DRYING ADVERTISED IN THE MOST RECENT MEDIUM
RANGE MODELS AS WE CLOSE OUT THE WORK WEEK. HOWEVER...ANOTHER
PACIFIC TROUGH SWINGS INLAND OVER THE WEEKEND AND WILL DRAW UP AT
LEAST ONE MORE ROUND MONSOONAL MOISTURE. TEMPERATURES WILL BE
RUNNING NEAR SEASONAL NORMS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 353 AM MDT SUN SEP 8 2013
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE FOUND ACROSS ALL OF
EASTERN UTAH AND WESTERN COLORADO THROUGH TONIGHT. HEAVY
RAIN...GUSTY AND ERRATIC WINDS TO 40 MPH AND SMALL HAIL WILL
ACCOMPANY THE STRONGEST STORMS. EXPECT AREAS OF MVFR CIGS AND
VSBYS WITH THE STRONGER STORMS...ALONG WITH LOCAL MOUNTAIN
OBSCURATION. THESE CONDITIONS WILL LIKELY CONTINUE THROUGH LATE
MONDAY EVENING.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH FROM NOON MDT TODAY THROUGH MONDAY EVENING FOR
COZ020-021.
UT...FLASH FLOOD WATCH FROM NOON MDT TODAY THROUGH MONDAY EVENING FOR
UTZ022-025-027>029.
&&
$$
SHORT TERM...JDC/JOE
LONG TERM...JOE/JDC
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS TAUNTON MA
734 AM EDT SUN SEP 8 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS SOUTHERN NEW ENGLAND TODAY AND MAY BE
PRECEDED BY A BRIEF SHOWER. HIGH PRESSURE WILL BRING COOLER
WEATHER TONIGHT AND MONDAY. WARMER AND MORE HUMID WEATHER WILL
RETURN BY MIDWEEK AS THIS HIGH BECOMES CENTERED OFFSHORE. ANOTHER
COLD FRONT MAY BRING SHOWERS AND THUNDERSTORMS LATER THIS WEEK
BEFORE ANOTHER HIGH PRESSURE RETURNS FOR NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
730 AM UPDATE...MINOR TWEAKS TO THE TIMING OF A COLD FRONT THIS
MORNING...AND THE RAINFALL CHANCES WHICH GO WITH IT. STILL LOOKS
LIKE ANY SHOWERS/SPRINKLES WE SEE TODAY WILL BE THIS MORNING...
WITH CLEARING AND GUSTY WINDS FOR THIS AFTERNOON FROM NORTHWEST TO
SOUTHEAST.
OTHERWISE...ADJUSTED NEAR-TERM CONDITIONS TO BRING THEM IN LINE
WITH OBSERVED TRENDS.
PREVIOUS DISCUSSION...
SMALL BAND OF SPRINKLES WAS PUSHING SOUTHWARD THROUGH REGION EARLY
THIS MORNING...ASSOCIATED WITH WEAK SURFACE TROUGH. EXPECT THIS
BAND TO DIMINISH AS IT REACHES S COAST PER HRRR. MEANWHILE NOT
MUCH HAPPENING UPSTREAM WITH COLD FRONT WHICH EXTENDED FROM
WESTERN AND NORTHERN NY INTO NORTHERN NEW ENGLAND. HRRR SEEMS TO
HAVE CORRECTLY BACKED OFF ON AREAL EXTENT OF SHOWERS AS FRONT
REACHES SOUTHERN NEW ENGLAND THIS MORNING...SO AM ONLY MENTIONING
ISOLATED SHOWERS AS ANY ACTIVITY WILL BE WIDELY SCATTERED.
FRONT SHOULD PUSH OFF S COAST EARLY THIS AFTERNOON. FAIRLY STRONG
COLD ADVECTION ASSOCIATED WITH HIGH PRESSURE BUILDING IN FROM
GREAT LAKES WILL RESULT IN A FEW HOURS OF BREEZY CONDITIONS LATER
THIS AFTERNOON...ESPECIALLY NEAR COAST. CLEARING WILL ALSO SET IN
FROM NW TO SE AS DRIER AIR ARRIVES.
GFS/NAM MOS ARE AT ODDS WITH EACH OTHER TODAY WITH NAM RUNNING
SEVERAL DEGREES WARMER AND GFS SEEMING TO BE TOO LOW CONSIDERING
AFTERNOON CLEARING. STAYED WITH CURRENT FORECAST OF HIGHS IN 60S
AND 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
WINDS DIMINISH QUICKLY THIS EVENING AS GRADIENT WEAKENS IN
RESPONSE TO HIGH PRESSURE BECOMING CENTERED OVER PA OVERNIGHT. DRY
AIRMASS IN PLACE WILL ALLOW FOR IDEAL RADIATIONAL COOLING.
CERTAINLY CAN SEE USUAL COLD SPOTS DROPPING INTO UPPER 30S BUT
WIDESPREAD MID 30S MAY BE A STRETCH...SO AM NOT ISSUING ANY FROST
ADVISORIES AT THIS TIME IN COLLABORATION WITH ALY/GYX. OTHERWISE A
CHILLY NIGHT AHEAD WITH LOWS IN 40S TO AROUND 50.
PLENTY OF SUNSHINE EXPECTED MON AS AIRMASS REMAINS DRY THROUGH
COLUMN PER MODEL CROSS SECTIONS. HIGH PRESSURE GRADUALLY HEADS
OFFSHORE RESULTING IN LIGHT S/SW FLOW...BUT NOT SOON ENOUGH TO
PREVENT SEA BREEZE DEVELOPMENT NEAR E MA COAST. LEANED CLOSER TO
GFS MOS FOR HIGHS /UPPER 60S COAST AND LOWER 70S INLAND/ WHICH
SEEMED MORE REASONABLE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
* A RETURN TO HEAT AND HUMIDITY MID WEEK
* CHANCE OF THUNDERSTORMS AS A COLD FRONT MOVES THROUGH THU-FRI
08/00Z MODELS REMAIN IN ABOVE AVERAGE AGREEMENT THROUGH THIS
PORTION OF THE FORECAST. THERE ARE SOME DIFFERENCES WITH THE
TIMING OF A COLD FRONT LATER THIS WEEK...AS WELL AS HOW ACTIVE A
PREFRONTAL TROUGH WILL BE AROUND WEDNESDAY. WILL GENERALLY FOLLOW
THE CONSENSUS TIMING...WITH SOME TWEAKS DETAILED BELOW.
MONDAY NIGHT-TUESDAY...A WARM FRONT APPROACHES OUR REGION WITH A
HIGH PRESSURE CENTERED SOUTH OF NOVA SCOTIA. MID AND HIGH LEVEL
CLOUDS SHOULD MOVE IN. TEMPERATURES EXPECTED TO BE RIGHT AROUND
NORMAL FOR SEPTEMBER.
TUESDAY...A WARM FRONT MOVES NORTHWARD THROUGH SOUTHERN NEW
ENGLAND...WITH A RETURN TO WARMER SOUTHWEST FLOW AT THE SURFACE.
TEMPERATURES WILL START WARMING TO ABOVE NORMAL. WITH THE ADDED
MOISTURE IN THE ATMOSPHERE AND THE HEATING AT THE SURFACE...
EXPECTING SOME DIURNAL CLOUDS TO DEVELOP. 08/00Z ECMWF CONTINUES
THE TREND FROM ITS PREVIOUS RUN AND IS MUCH MORE AGGRESSIVE THAN
THE OTHER GUIDANCE DEVELOPING SHOWERS. WITH THE BEST DYNAMICS
LIKELY REMAINING TO OUR NORTH AND WEST...THINK THIS MODEL IS
OVERDONE. THINKING MORE ALONG THE LINES OF ISOLATED TO SCATTERED
SPRINKLES AT THIS POINT.
WEDNESDAY...THERE START TO BE SOME TIMING DIFFERENCES HERE IN THE
MODELS REGARDING THE ONSET OF SHOWERS AND THUNDERSTORMS ACROSS THE
REGION. THE GFS STARTS EXHIBITING SOME QPF WEDNESDAY AFTERNOON
ACROSS THE NORTHWESTERN ZONES AND THEN BUILDING EASTWARD THROUGH THE
AREA THROUGH WEDNESDAY NIGHT. THE ECMWF KEEPS THIS DAY DRY AND
STARTS MOVING SHOWERS INTO THE NORTHWESTERN ZONES LATE WEDNESDAY
NIGHT...KEEPING THE BULK OF THE RAINFALL TO THURSDAY.
WHILE THERE SHOULD BE A PREFRONTAL TROUGH NEARBY...THERE IS STILL
NOT A LOT OF SYNOPTIC SUPPORT OR INSTABILITY. MID LEVEL LAPSE
RATES IN THE GFS ARE A LITTLE MORE UNSTABLE THAN MOIST ADIABATIC.
WILL WE CANNOT RULE SOME ISOLATED SHOWERS OR THUNDERSTORMS...
LEANING AWAY FROM THE WIDESPREAD DOWNPOURS DEPICTED BY THE GFS.
THIS WILL BE THE WARMEST...AND LIKELY THE MOST HUMID...DAY OF THIS
WEEK.
THURSDAY...ANOTHER WARM DAY WITH UNCOMFORTABLE DEWPOINTS. A COLD
FRONT IS EXPECTED THURSDAY NIGHT INTO FRIDAY MORNING. DEPENDING
ON ITS TIMING...STRONG THUNDERSTORMS ARE A RISK AGAIN THURSDAY WITH
A SURFACE TROUGH AHEAD OF THE FRONT INDUCING SURFACE CONVERGENCE
AND DESTABILIZATION. ALSO...AMPLE CAPE...BORDERLINE SHEAR AND
DECENT SEVERE PARAMETERS SHOULD EXIST. THE BIG QUESTION...ALONG
WITH FRONTAL TIMING...IS CLOUD COVER. IT MAY BE TOO CLOUDY TO
GENERATE MUCH SURFACE DESTABILIZATION.
FRIDAY-SATURDAY...ANY LEFTOVER SHOWERS EXIT OFF THE COAST FRIDAY
MORNING WITH THE FRONT AND A HIGH PRESSURE TAKES ITS PLACE.
SATURDAY MORNING SHOULD START ANOTHER PERIOD OF BELOW NORMAL
TEMPERATURES. THE MOIST AIR SHOULD LEAVE WITH THE COLD FRONT AS
THIS HIGH PRESSURE BRINGS IN DRIER CONDITIONS.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW /THROUGH MONDAY/...HIGH CONFIDENCE.
OTHERWISE VFR CIGS AOA 060 THROUGH THIS MORNING WITH SCATTERED
SPRINKLES...PROBABLY NOT ENOUGH TO WET RUNWAYS.
CLEARING THIS AFTERNOON FROM NW TO SE WITH INCREASING N/NW WINDS
GUSTING TO 20-25KT. STRONGEST GUSTS ALONG COAST 21Z-03Z BEFORE
WINDS SUBSIDE. ONCE AGAIN PATCHY FOG WILL BRING LOCAL MVFR/IFR TO
INTERIOR VALLEYS TONIGHT.
VFR MON. SEA BREEZES EXPECTED NEAR E MA COAST 15Z-23Z BEFORE WINDS
BECOME S/SW. SHOULD SEE S/SW WINDS ALL DAY NEAR S COAST.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK...TUESDAY THROUGH THURSDAY...
TUESDAY...HIGH CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF
MVFR/IFR CONDITIONS IN FOG DURING THE OVERNIGHT.
WEDNESDAY AND THURSDAY...MODERATE CONFIDENCE. MAINLY VFR. MODERATE
PROBABILITY OF MVFR/IFR CONDITIONS IN SHRA/TSRA/FG FROM WEDNESDAY
NIGHT INTO THURSDAY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH MONDAY/...HIGH CONFIDENCE.
EXPANDED SCA TO INCLUDE ALL WATERS EXCEPT NARRAGANSETT BAY FROM
THIS AFTERNOON INTO TONIGHT. WINDS DIMINISH THIS EVENING BUT SEAS
ON OUTER WATERS WILL TAKE MORE TIME TO SUBSIDE BELOW 5 FT.
COLD FRONT CROSSES WATERS LATER THIS MORNING AND EARLY THIS
AFTERNOON WITH NOTHING MORE THAN BRIEF SHOWER. LIGHT W/SW WINDS
AHEAD OF FRONT SHIFT TO N/NW WITH PERIOD OF 25KT GUSTS EXPECTED
FROM MID AFTERNOON THROUGH EARLY TONIGHT...ESPECIALLY ON E MA
WATERS AND AROUND CAPE COD.
TIMING OF HIGHER GUSTS ON BUZZARDS BAY AND VINEYARD SOUND WILL
COINCIDE WITH INCOMING TIDE AGAINST N WIND /LOW TIDE AROUND 4 PM
AND HIGH TIDE AROUND 1030 PM/. THIS WILL RESULT IN STEEP WAVES
LATER THIS AFTERNOON AND ESPECIALLY THIS EVENING. SIMILAR
SITUATION ON CAPE COD BAY WITH DEPARTING TIDE AGAINST N WIND LATER
THIS AFTERNOON /HIGH TIDE AROUND 2 PM AND LOW TIDE AROUND 8 PM/.
HIGH PRESSURE SLOWLY HEADS OFFSHORE MON WITH LIGHT S/SW FLOW...
BUT SEA BREEZE EXPECTED ALONG E MA COAST BEFORE WINDS TURN S
TOWARD EVENING.
OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...
QUIET BOATING WEATHER EXPECTED TUESDAY. SEAS INCREASE TO AROUND
5-6 FEET ACROSS THE OUTER WATERS WEDNESDAY INTO THURSDAY IN
ADVANCE OF A COLD FRONT MOVING TOWARDS THE WATERS. WINDS HAVE THE
POTENTIAL TO GUST TO NEAR 25 KTS EACH AFTERNOON TUESDAY THROUGH
THURSDAY...PARTICULARLY ACROSS THE NEAR SHORE WATERS SURROUNDING
CAPE COD AND THE ISLANDS. THERE IS A LOW PROBABILITY OF SHOWERS
AND THUNDERSTORMS OVER THE WATERS THURSDAY.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EDT
TONIGHT FOR ANZ231>235-237.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 8 PM EDT THIS
EVENING FOR ANZ230.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM EDT
MONDAY FOR ANZ250.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT EDT
TONIGHT FOR ANZ251.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT MONDAY
FOR ANZ254>256.
&&
$$
SYNOPSIS...BELK/JWD
NEAR TERM...BELK/JWD
SHORT TERM...JWD
LONG TERM...BELK
AVIATION...BELK/JWD
MARINE...BELK/JWD
AREA FORECAST DISCUSSION
NWS TAUNTON MA
417 AM EDT SUN SEP 8 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS SOUTHERN NEW ENGLAND TODAY AND MAY BE
PRECEDED BY A BRIEF SHOWER. HIGH PRESSURE WILL BRING COOLER
WEATHER TONIGHT AND MONDAY. WARMER AND MORE HUMID WEATHER WILL
RETURN BY MIDWEEK AS THIS HIGH BECOMES CENTERED OFFSHORE. ANOTHER
COLD FRONT MAY BRING SHOWERS AND THUNDERSTORMS LATER THIS WEEK
BEFORE ANOTHER HIGH PRESSURE RETURNS FOR NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
3 AM UPDATE...
SMALL BAND OF SPRINKLES WAS PUSHING SOUTHWARD THROUGH REGION EARLY
THIS MORNING...ASSOCIATED WITH WEAK SURFACE TROUGH. EXPECT THIS
BAND TO DIMINISH AS IT REACHES S COAST PER HRRR. MEANWHILE NOT
MUCH HAPPENING UPSTREAM WITH COLD FRONT WHICH EXTENDED FROM
WESTERN AND NORTHERN NY INTO NORTHERN NEW ENGLAND. HRRR SEEMS TO
HAVE CORRECTLY BACKED OFF ON AREAL EXTENT OF SHOWERS AS FRONT
REACHES SOUTHERN NEW ENGLAND THIS MORNING...SO AM ONLY MENTIONING
ISOLATED SHOWERS AS ANY ACTIVITY WILL BE WIDELY SCATTERED.
FRONT SHOULD PUSH OFF S COAST EARLY THIS AFTERNOON. FAIRLY STRONG
COLD ADVECTION ASSOCIATED WITH HIGH PRESSURE BUILDING IN FROM
GREAT LAKES WILL RESULT IN A FEW HOURS OF BREEZY CONDITIONS LATER
THIS AFTERNOON...ESPECIALLY NEAR COAST. CLEARING WILL ALSO SET IN
FROM NW TO SE AS DRIER AIR ARRIVES.
GFS/NAM MOS ARE AT ODDS WITH EACH OTHER TODAY WITH NAM RUNNING
SEVERAL DEGREES WARMER AND GFS SEEMING TO BE TOO LOW CONSIDERING
AFTERNOON CLEARING. STAYED WITH CURRENT FORECAST OF HIGHS IN 60S
AND 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
WINDS DIMINISH QUICKLY THIS EVENING AS GRADIENT WEAKENS IN
RESPONSE TO HIGH PRESSURE BECOMING CENTERED OVER PA OVERNIGHT. DRY
AIRMASS IN PLACE WILL ALLOW FOR IDEAL RADIATIONAL COOLING.
CERTAINLY CAN SEE USUAL COLD SPOTS DROPPING INTO UPPER 30S BUT
WIDESPREAD MID 30S MAY BE A STRETCH...SO AM NOT ISSUING ANY FROST
ADVISORIES AT THIS TIME IN COLLABORATION WITH ALY/GYX. OTHERWISE A
CHILLY NIGHT AHEAD WITH LOWS IN 40S TO AROUND 50.
PLENTY OF SUNSHINE EXPECTED MON AS AIRMASS REMAINS DRY THROUGH
COLUMN PER MODEL CROSS SECTIONS. HIGH PRESSURE GRADUALLY HEADS
OFFSHORE RESULTING IN LIGHT S/SW FLOW...BUT NOT SOON ENOUGH TO
PREVENT SEA BREEZE DEVELOPMENT NEAR E MA COAST. LEANED CLOSER TO
GFS MOS FOR HIGHS /UPPER 60S COAST AND LOWER 70S INLAND/ WHICH
SEEMED MORE REASONABLE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
* A RETURN TO HEAT AND HUMIDITY MID WEEK
* CHANCE OF THUNDERSTORMS AS A COLD FRONT MOVES THROUGH THU-FRI
08/00Z MODELS REMAIN IN ABOVE AVERAGE AGREEMENT THROUGH THIS
PORTION OF THE FORECAST. THERE ARE SOME DIFFERENCES WITH THE
TIMING OF A COLD FRONT LATER THIS WEEK...AS WELL AS HOW ACTIVE A
PREFRONTAL TROUGH WILL BE AROUND WEDNESDAY. WILL GENERALLY FOLLOW
THE CONSENSUS TIMING...WITH SOME TWEAKS DETAILED BELOW.
MONDAY NIGHT-TUESDAY...A WARM FRONT APPROACHES OUR REGION WITH A
HIGH PRESSURE CENTERED SOUTH OF NOVA SCOTIA. MID AND HIGH LEVEL
CLOUDS SHOULD MOVE IN. TEMPERATURES EXPECTED TO BE RIGHT AROUND
NORMAL FOR SEPTEMBER.
TUESDAY...A WARM FRONT MOVES NORTHWARD THROUGH SOUTHERN NEW
ENGLAND...WITH A RETURN TO WARMER SOUTHWEST FLOW AT THE SURFACE.
TEMPERATURES WILL START WARMING TO ABOVE NORMAL. WITH THE ADDED
MOISTURE IN THE ATMOSPHERE AND THE HEATING AT THE SURFACE...
EXPECTING SOME DIURNAL CLOUDS TO DEVELOP. 08/00Z ECMWF CONTINUES
THE TREND FROM ITS PREVIOUS RUN AND IS MUCH MORE AGGRESSIVE THAN
THE OTHER GUIDANCE DEVELOPING SHOWERS. WITH THE BEST DYNAMICS
LIKELY REMAINING TO OUR NORTH AND WEST...THINK THIS MODEL IS
OVERDONE. THINKING MORE ALONG THE LINES OF ISOLATED TO SCATTERED
SPRINKLES AT THIS POINT.
WEDNESDAY...THERE START TO BE SOME TIMING DIFFERENCES HERE IN THE
MODELS REGARDING THE ONSET OF SHOWERS AND THUNDERSTORMS ACROSS THE
REGION. THE GFS STARTS EXHIBITING SOME QPF WEDNESDAY AFTERNOON
ACROSS THE NORTHWESTERN ZONES AND THEN BUILDING EASTWARD THROUGH THE
AREA THROUGH WEDNESDAY NIGHT. THE ECMWF KEEPS THIS DAY DRY AND
STARTS MOVING SHOWERS INTO THE NORTHWESTERN ZONES LATE WEDNESDAY
NIGHT...KEEPING THE BULK OF THE RAINFALL TO THURSDAY.
WHILE THERE SHOULD BE A PREFRONTAL TROUGH NEARBY...THERE IS STILL
NOT A LOT OF SYNOPTIC SUPPORT OR INSTABILITY. MID LEVEL LAPSE
RATES IN THE GFS ARE A LITTLE MORE UNSTABLE THAN MOIST ADIABATIC.
WILL WE CANNOT RULE SOME ISOLATED SHOWERS OR THUNDERSTORMS...
LEANING AWAY FROM THE WIDESPREAD DOWNPOURS DEPICTED BY THE GFS.
THIS WILL BE THE WARMEST...AND LIKELY THE MOST HUMID...DAY OF THIS
WEEK.
THURSDAY...ANOTHER WARM DAY WITH UNCOMFORTABLE DEWPOINTS. A COLD
FRONT IS EXPECTED THURSDAY NIGHT INTO FRIDAY MORNING. DEPENDING
ON ITS TIMING...STRONG THUNDERSTORMS ARE A RISK AGAIN THURSDAY WITH
A SURFACE TROUGH AHEAD OF THE FRONT INDUCING SURFACE CONVERGENCE
AND DESTABILIZATION. ALSO...AMPLE CAPE...BORDERLINE SHEAR AND
DECENT SEVERE PARAMETERS SHOULD EXIST. THE BIG QUESTION...ALONG
WITH FRONTAL TIMING...IS CLOUD COVER. IT MAY BE TOO CLOUDY TO
GENERATE MUCH SURFACE DESTABILIZATION.
FRIDAY-SATURDAY...ANY LEFTOVER SHOWERS EXIT OFF THE COAST FRIDAY
MORNING WITH THE FRONT AND A HIGH PRESSURE TAKES ITS PLACE.
SATURDAY MORNING SHOULD START ANOTHER PERIOD OF BELOW NORMAL
TEMPERATURES. THE MOIST AIR SHOULD LEAVE WITH THE COLD FRONT AS
THIS HIGH PRESSURE BRINGS IN DRIER CONDITIONS.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW /THROUGH MONDAY/...HIGH CONFIDENCE.
PATCHY MVFR/IFR THROUGH 12Z IN FOG...MAINLY IN CT RIVER VALLEY OF
MA/NH. OTHERWISE VFR CIGS AOA 060 THROUGH THIS MORNING WITH
SCATTERED SPRINKLES...PROBABLY NOT ENOUGH TO WET RUNWAYS.
CLEARING THIS AFTERNOON FROM NW TO SE WITH INCREASING N/NW WINDS
GUSTING TO 20-25KT. STRONGEST GUSTS ALONG COAST 21Z-03Z BEFORE
WINDS SUBSIDE. ONCE AGAIN PATCHY FOG WILL BRING LOCAL MVFR/IFR TO
INTERIOR VALLEYS.
VFR MON. SEA BREEZES EXPECTED NEAR E MA COAST 15Z-23Z BEFORE WINDS
BECOME S/SW. SHOULD SEE S/SW WINDS ALL DAY NEAR S COAST.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK...TUESDAY THROUGH THURSDAY...
TUESDAY...HIGH CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF
MVFR/IFR CONDITIONS IN FOG DURING THE OVERNIGHT.
WEDNESDAY AND THURSDAY...MODERATE CONFIDENCE. MAINLY VFR. MODERATE
PROBABILITY OF MVFR/IFR CONDITIONS IN SHRA/TSRA/FG FROM WEDNESDAY
NIGHT INTO THURSDAY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH MONDAY/...HIGH CONFIDENCE.
EXPANDED SCA TO INCLUDE ALL WATERS EXCEPT NARRAGANSETT BAY FROM
THIS AFTERNOON INTO TONIGHT. WINDS DIMINISH THIS EVENING BUT SEAS
ON OUTER WATERS WILL TAKE MORE TIME TO SUBSIDE BELOW 5 FT.
COLD FRONT CROSSES WATERS LATER THIS MORNING AND EARLY THIS
AFTERNOON WITH NOTHING MORE THAN BRIEF SHOWER. LIGHT W/SW WINDS
AHEAD OF FRONT SHIFT TO N/NW WITH PERIOD OF 25KT GUSTS EXPECTED
FROM MID AFTERNOON THROUGH EARLY TONIGHT...ESPECIALLY ON E MA
WATERS AND AROUND CAPE COD.
TIMING OF HIGHER GUSTS ON BUZZARDS BAY AND VINEYARD SOUND WILL
COINCIDE WITH INCOMING TIDE AGAINST N WIND /LOW TIDE AROUND 4 PM
AND HIGH TIDE AROUND 1030 PM/. THIS WILL RESULT IN STEEP WAVES
LATER THIS AFTERNOON AND ESPECIALLY THIS EVENING. SIMILAR
SITUATION ON CAPE COD BAY WITH DEPARTING TIDE AGAINST N WIND LATER
THIS AFTERNOON /HIGH TIDE AROUND 2 PM AND LOW TIDE AROUND 8 PM/.
HIGH PRESSURE SLOWLY HEADS OFFSHORE MON WITH LIGHT S/SW FLOW...
BUT SEA BREEZE EXPECTED ALONG E MA COAST BEFORE WINDS TURN S
TOWARD EVENING.
OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...
QUIET BOATING WEATHER EXPECTED TUESDAY. SEAS INCREASE TO AROUND
5-6 FEET ACROSS THE OUTER WATERS WEDNESDAY INTO THURSDAY IN
ADVANCE OF A COLD FRONT MOVING TOWARDS THE WATERS. WINDS HAVE THE
POTENTIAL TO GUST TO NEAR 25 KTS EACH AFTERNOON TUESDAY THROUGH
THURSDAY...PARTICULARLY ACROSS THE NEAR SHORE WATERS SURROUNDING
CAPE COD AND THE ISLANDS. THERE IS A LOW PROBABILITY OF SHOWERS
AND THUNDERSTORMS OVER THE WATERS THURSDAY.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EDT
TONIGHT FOR ANZ231>235-237.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 8 PM EDT THIS
EVENING FOR ANZ230.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM EDT
MONDAY FOR ANZ250.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT EDT
TONIGHT FOR ANZ251.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT MONDAY
FOR ANZ254>256.
&&
$$
SYNOPSIS...JWD/BELK
NEAR TERM...JWD
SHORT TERM...JWD
LONG TERM...BELK
AVIATION...JWD/BELK
MARINE...JWD/BELK
AREA FORECAST DISCUSSION
NWS TAUNTON MA
258 AM EDT SUN SEP 8 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS SOUTHERN NEW ENGLAND TODAY AND MAY BE
PRECEDED BY A BRIEF SHOWER. HIGH PRESSURE WILL BRING COOLER
WEATHER TONIGHT AND MONDAY. WARMER AND MORE HUMID WEATHER WILL
RETURN BY MIDWEEK AS THE HIGH BECOMES CENTERED OFFSHORE. ANOTHER
COLD FRONT MAY BRING SHOWERS AND THUNDERSTORMS LATER THIS WEEK
BEFORE HIGH PRESSURE RETURNS FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
3 AM UPDATE...
SMALL BAND OF SPRINKLES WAS PUSHING SOUTHWARD THROUGH REGION EARLY
THIS MORNING...ASSOCIATED WITH WEAK SURFACE TROUGH. EXPECT THIS
BAND TO DIMINISH AS IT REACHES S COAST PER HRRR. MEANWHILE NOT
MUCH HAPPENING UPSTREAM WITH COLD FRONT WHICH EXTENDED FROM
WESTERN AND NORTHERN NY INTO NORTHERN NEW ENGLAND. HRRR SEEMS TO
HAVE CORRECTLY BACKED OFF ON AREAL EXTENT OF SHOWERS AS FRONT
REACHES SOUTHERN NEW ENGLAND THIS MORNING...SO AM ONLY MENTIONING
ISOLATED SHOWERS AS ANY ACTIVITY WILL BE WIDELY SCATTERED.
FRONT SHOULD PUSH OFF S COAST EARLY THIS AFTERNOON. FAIRLY STRONG
COLD ADVECTION ASSOCIATED WITH HIGH PRESSURE BUILDING IN FROM
GREAT LAKES WILL RESULT IN A FEW HOURS OF BREEZY CONDITIONS LATER
THIS AFTERNOON...ESPECIALLY NEAR COAST. CLEARING WILL ALSO SET IN
FROM NW TO SE AS DRIER AIR ARRIVES.
GFS/NAM MOS ARE AT ODDS WITH EACH OTHER TODAY WITH NAM RUNNING
SEVERAL DEGREES WARMER AND GFS SEEMING TO BE TOO LOW CONSIDERING
AFTERNOON CLEARING. STAYED WITH CURRENT FORECAST OF HIGHS IN 60S
AND 70S.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM MONDAY/...
WINDS DIMINISH QUICKLY THIS EVENING AS GRADIENT WEAKENS IN
RESPONSE TO HIGH PRESSURE BECOMING CENTERED OVER PA OVERNIGHT. DRY
AIRMASS IN PLACE WILL ALLOW FOR IDEAL RADIATIONAL COOLING.
CERTAINLY CAN SEE USUAL COLD SPOTS DROPPING INTO UPPER 30S BUT
WIDESPREAD MID 30S MAY BE A STRETCH...SO AM NOT ISSUING ANY FROST
ADVISORIES AT THIS TIME IN COLLABORATION WITH ALY/GYX. OTHERWISE A
CHILLY NIGHT AHEAD WITH LOWS IN 40S TO AROUND 50.
PLENTY OF SUNSHINE EXPECTED MON AS AIRMASS REMAINS DRY THROUGH
COLUMN PER MODEL CROSS SECTIONS. HIGH PRESSURE GRADUALLY HEADS
OFFSHORE RESULTING IN LIGHT S/SW FLOW...BUT NOT SOON ENOUGH TO
PREVENT SEA BREEZE DEVELOPMENT NEAR E MA COAST. LEANED CLOSER TO
GFS MOS FOR HIGHS /UPPER 60S COAST AND LOWER 70S INLAND/ WHICH
SEEMED MORE REASONABLE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
* HIGH PRESSURE EARLY IN THE WEEK
* A RETURN TO SUMMER LIKE TEMPERATURES MID WEEK
* CHANCE OF STORMS AS COLD FRONT MOVES THROUGH WED-THU
MODELS ARE IN GOOD AGREEMENT THROUGH MUCH OF THE LONG TERM. AS
USUAL...THERE ARE SOME TIMING DIFFERENCES IN THE LATER PART OF THE
LONG TERM BUT OTHERWISE...EXCELLENT AGREEMENT ON THE GENERAL
SYNOPTIC PATTERN. HIGH PRESSURE EARLY IN THE WEEK WILL MOVE OFFSHORE
ALLOWING A WARM FRONT TO MOVE NORTH THROUGH SOUTHERN NEW ENGLAND.
THIS WILL BRING A RETURN OF SUMMER LIKE HEAT AND HUMIDITY WEDNESDAY
BEFORE A COLD FRONT MOVES THROUGH THURSDAY. THIS SUMMER LIKE
ATMOSPHERE ALSO WILL ALLOW FOR ANOTHER DAY OF SHOWERS AND
THUNDERSTORMS THURSDAY. THEN HIGH PRESSURE MOVES BACK INTO THE
REGION TOWARDS THE END OF THE WEEK...RETURNING TEMPERATURES TO
NORMAL FOR SEPTEMBER.
MONDAY...HIGH PRESSURE MOVES OFFSHORE AS LOW PRESSURE MOVES INTO THE
GREAT LAKES. MUCH OF THE PERIOD WILL BE FAIR...WITH CLOUDS STARTING
TO MOVE IN DURING THE OVERNIGHT WITH A WARM FRONT STARTING TO SURGE
NORTHWARD. TEMPERATURES WILL BE RIGHT AROUND NORMAL FOR SEPTEMBER.
TUESDAY...THE WARM FRONT MOVES NORTHWARD THROUGH SOUTHERN NEW
ENGLAND...WITH A RETURN TO WARMER SOUTHWESTERLY FLOW AT THE SURFACE.
TEMPERATURES WILL START WARMING TO ABOVE NORMAL. WITH THE ADDED
MOISTURE IN THE ATMOSPHERE AND THE HEATING AT THE SURFACE...EXPECT
SOME DIURNAL CLOUDS TO DEVELOP BUT THE AREA SHOULD OTHERWISE REMAIN
DRY.
WEDNESDAY...THERE START TO BE SOME TIMING DIFFERENCES HERE IN THE
MODELS REGARDING THE ONSET OF SHOWERS AND THUNDERSTORMS ACROSS THE
REGION. THE GFS STARTS EXHIBITING SOME QPF WEDNESDAY AFTERNOON
ACROSS THE NORTHWESTERN ZONES AND THEN BUILDING EASTWARD THROUGH THE
AREA THROUGH WEDNESDAY NIGHT. THE ECMWF KEEPS THE DAY DRY AND
STARTS MOVING SHOWERS INTO THE NORTHWESTERN ZONES LATE WEDNESDAY
NIGHT...KEEPING THE BULK OF THE PRECIP TO THURSDAY. THIS WILL BE
THE WARMEST DAY OF THE WEEK...WITH TEMPS INTO THE 80S AND POSSIBLY
NEAR 90.
THURSDAY...A SECOND WARM DAY WITH UNCOMFORTABLE DEWPOINTS. COLD
FROPA IS EXPECTED OVERNIGHT INTO FRIDAY MORNING. DEPENDING ON
TIMING...STRONG THUNDERSTORMS ARE A RISK AGAIN TODAY WITH A
SURFACE TROUGH AHEAD OF THE FRONT INDICATING SURFACE
DESTABILIZATION. ALSO...AMPLE CAPE...BORDERLINE SHEAR AND DECENT
SEVERE PARAMETERS SHOULD EXIST. BIG QUESTION...ALONG WITH FROPA
TIMING...IS CLOUD COVER AS TOO MUCH MAY BE AROUND TO ALLOW FOR
NEEDED SURFACE DESTABILIZATION.
FRIDAY-SATURDAY...ANY LEFTOVER SHOWERS EXIT OFF THE COAST IN THE AM
WITH THE FRONT AND HIGH PRESSURE TAKES ITS PLACE. SATURDAY SHOULD
HAVE COLD MORNING TEMPERATURES FROM THE CANADIAN HIGH PRESSURE
SYSTEM. THE MOIST AIR SHOULD LEAVE WITH THE COLD FRONT AND THE HIGH
SHOULD BRING IN DRIER CONDITIONS.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW /THROUGH MONDAY/...HIGH CONFIDENCE.
PATCHY MVFR/IFR THROUGH 12Z IN FOG...MAINLY IN CT RIVER VALLEY OF
MA/NH. OTHERWISE VFR CIGS AOA 060 THROUGH THIS MORNING WITH
SCATTERED SPRINKLES...PROBABLY NOT ENOUGH TO WET RUNWAYS.
CLEARING THIS AFTERNOON FROM NW TO SE WITH INCREASING N/NW WINDS
GUSTING TO 20-25KT. STRONGEST GUSTS ALONG COAST 21Z-03Z BEFORE
WINDS SUBSIDE. ONCE AGAIN PATCHY FOG WILL BRING LOCAL MVFR/IFR TO
INTERIOR VALLEYS.
VFR MON. SEA BREEZES EXPECTED NEAR E MA COAST 15Z-23Z BEFORE WINDS
BECOME S/SW. SHOULD SEE S/SW WINDS ALL DAY NEAR S COAST.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK...TUESDAY THROUGH THURSDAY...
TUESDAY...HIGH CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF
MVFR/IFR CONDITIONS IN FOG DURING THE OVERNIGHT PERIODS.
WEDNESDAY AND THURSDAY...MODERATE CONFIDENCE. MAINLY VFR. MODERATE
PROBABILITY OF MVFR/IFR CONDITIONS IN SHRA/TSRA/FG FROM WEDNESDAY
NIGHT INTO THURSDAY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SUNDAY NIGHT/...HIGH CONFIDENCE.
EXPANDED SCA TO INCLUDE ALL WATERS EXCEPT NARRAGANSETT BAY FROM
THIS AFTERNOON INTO TONIGHT. WINDS DIMINISH THIS EVENING BUT SEAS
ON OUTER WATERS WILL TAKE MORE TIME TO SUBSIDE BELOW 5 FT.
COLD FRONT CROSSES WATERS LATER THIS MORNING AND EARLY THIS
AFTERNOON WITH NOTHING MORE THAN BRIEF SHOWER. LIGHT W/SW WINDS
AHEAD OF FRONT SHIFT TO N/NW WITH PERIOD OF 25KT GUSTS EXPECTED
FROM MID AFTERNOON THROUGH EARLY TONIGHT...ESPECIALLY ON E MA
WATERS AND AROUND CAPE COD.
TIMING OF HIGHER GUSTS ON BUZZARDS BAY AND VINEYARD SOUND WILL
COINCIDE WITH INCOMING TIDE AGAINST N WIND /LOW TIDE AROUND 4 PM
AND HIGH TIDE AROUND 1030 PM/. THIS WILL RESULT IN STEEP WAVES
LATER THIS AFTERNOON AND ESPECIALLY THIS EVENING. SIMILAR
SITUATION ON CAPE COD BAY WITH DEPARTING TIDE AGAINST N WIND LATER
THIS AFTERNOON /HIGH TIDE AROUND 2 PM AND LOW TIDE AROUND 8 PM/.
HIGH PRESSURE SLOWLY HEADS OFFSHORE MON WITH LIGHT S/SW FLOW...
BUT SEA BREEZE EXPECTED ALONG E MA COAST BEFORE WINDS TURN S
TOWARD EVENING.
OUTLOOK...TUESDAY THROUGH THURSDAY...
QUIET BOATING WEATHER EXPECTED TUESDAY. SEAS INCREASE TO AROUND
5-6 FEET ON THE OUTER WATERS WEDNESDAY AND THURSDAY IN ADVANCE OF
A COLD FRONT MOVING OVER THE WATERS. WINDS HAVE THE POTENTIAL TO
GUST TO NEAR 25 KTS EACH AFTERNOON TUESDAY THROUGH
THURSDAY...PARTICULARLY ON THE NEAR SHORE WATERS SURROUNDING CAPE
COD AND THE ISLANDS. THERE IS A LOW PROBABILITY OF SHOWERS AND
THUNDERSTORMS OVER THE WATERS ON THURSDAY.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EDT
TONIGHT FOR ANZ231>235-237.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 8 PM EDT THIS
EVENING FOR ANZ230.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM EDT
MONDAY FOR ANZ250.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT EDT
TONIGHT FOR ANZ251.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT MONDAY
FOR ANZ254>256.
&&
$$
SYNOPSIS...BELK/JWD
NEAR TERM...JWD
SHORT TERM...JWD
LONG TERM...RLG/99
AVIATION...BELK/JWD
MARINE...BELK/JWD
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
520 AM EDT SUN SEP 8 2013
.SYNOPSIS..
09Z WATER VAPOR AND H4 RAP ANALYSIS SHOWING A LARGE AREA OF UPPER
RIDGING OVER THE CENTRAL CONUS BEGINNING TO SPREAD EASTWARD WHILE
THE VERY TAIL END OF WEAK TROUGHING OVER THE WESTERN ATLANTIC
REACHES ALL THE WAY SOUTH AND SOUTHWEST TO THE FLORIDA EAST COAST.
WV IMAGERY INDICATES DEFINED DRYING/SUBSIDENCE IN THE MID/UPPER
LEVELS ADVECTING SOUTHWARD WITHIN THE SYNOPTIC FLOW BETWEEN THESE
TWO FEATURES. THE DRY AIR ALOFT HAS MADE PROGRESS SOUTHWARD INTO THE
NORTHERN FL PENINSULA DURING THE PAST 12-18 HOURS AND NWP GUIDANCE
ALL SUGGEST FURTHER SOUTHWARD PENETRATION THROUGH THE DAYLIGHT HOURS
TODAY.
AT THE SURFACE...GRADIENT IS RATHER RELAXED FOR THE FINAL DAY OF THE
WEEKEND WITH WEAK HIGH PRESSURE TO OUR NORTH. THE FLOW AROUND THIS
RIDGE IS LIGHT EAST TO NORTHEAST UNDER MOSTLY CLEAR SKIES. JUST A
FEW ISOLATED STORMS WELL OFFSHORE THIS MORNING ALONG THE LAND BREEZE
CONVERGENCE ZONE FROM THE PENINSULA AND PANHANDLE. TEMPERATURES ARE
COMFORTABLE FOR EARLY SEPTEMBER WITH SOME INLAND STATIONS TO THE
NORTH OF I-4 DROPPING INTO THE UPPER 60S. THE COOLER TEMPERATURES
ARE ALLOWING FOR SOME PATCHY SHALLOW GROUND FOG WHICH SHOULD BURN
OFF WITHIN AN HOUR OR 2 OF SUNRISE.
&&
.SHORT TERM (TODAY THROUGH TUESDAY)...
TODAY/TONIGHT...
A GENERALLY PLEASANT EARLY SEPTEMBER DAY APPEARS ON TAP FOR MUCH OF
WEST-CENTRAL AND SOUTHWEST FLORIDA. GUIDANCE ENSEMBLES
CROSS-SECTIONS AGREE ON A SOUTHWARD EXPANSION OF DEEP LAYER DRY AIR
ABOVE 700MB THAT HAS ALREADY MADE ITS WAY INTO THE NORTHERN HALF OF
THE FLORIDA PENINSULA...ALONG WITH COINCIDENT SUPPRESSION/ Q-VECTOR
DIVERGENCE. THERE IS A SHALLOW LAYER OF MOISTURE TRAPPED UNDER THIS
LAYER...SO SHOULD SEE THE MOSTLY SUNNY SKIES THIS MORNING GIVE WAY
TO A SHALLOW SCT CU FIELD BY EARLY AFTERNOON. THE DEPTH OF THE DRY
AIR AND SUBSTANTIAL ENTRAINMENT OF LOW THETA-E AIR INTO ANY UPDRAFT
COLUMN SHOULD KEEP ANY DIURNAL CONVECTION ISOLATED IN NATURE FROM
THE TAMPA BAY / I-4 CORRIDOR NORTHWARD THROUGH THE NATURE COAST
ZONES. THE COLUMN OF DRY AIR BECOME SLIGHTLY LESS DEEP THE FURTHER
SOUTH ONE TRAVELS AND RETURN RAIN CHANCES TO THE CHANCE 30-50% RANGE
SOUTH OF TAMPA BAY AND ESPECIALLY DOWN TOWARD FORT MYERS.
HOWEVER...EVEN FOR THESE SOUTHERN ZONES...OVERALL COVERAGE OF STORMS
SHOULD BE LESS THAN PREVIOUS DAYS...AND STORMS THAT DO DEVELOP
SHOULD BE LATE DAY AND BRIEF IN DURATION. ANY CELLS THAT REACH A
SUFFICIENT DEPTH WILL BEGIN TO FIGHT THIS HOSTILE AIRMASS ALOFT AND
HASTEN THEIR DEMISE. TEMPERATURES LOOK SEASONABLE WITH LOWER 90S
COMMON BY MID AFTERNOON.
ANY EVENING STORMS NEAR THE COAST SOUTH OF TAMPA BAY SHOULD EXIT OFF
THE OFFSHORE BY 10-11PM...AND GIVE A GENERALLY DRY OVERNIGHT PERIOD
TO ALL ZONES. THE DRIER COLUMN...MOSTLY CLEAR SKIES AND LIGHT
WINDS...SIMILAR TO AREAS NORTH THIS MORNING...ALLOW TEMPERATURES TO
REACH COMFORTABLE LEVELS FOR EARLY SEPTEMBER. NORMALLY COOLER SPOTS
ACROSS THE NATURE COAST IN CLOSEST PROXIMITY TO THE SURFACE RIDGE
ARE LIKELY TO AGAIN DROP INTO THE UPPER 60S TOWARD DAWN.
MONDAY THROUGH TUESDAY...
UPPER LEVEL RIDGING WILL ESTABLISH ITSELF OVER THE SOUTHEASTERN
CONUS WHILE WEAK TROUGHING / RESIDUAL ENERGY TRIES TO CONSOLIDATE
EAST OF THE FL PENINSULA. OUR REGION WILL REMAIN BETWEEN THESE
FEATURES WITHIN THE SAME ZONE OF WEAK SUBSIDENCE / DRIER AIR ALOFT.
THE LESS THAN FAVORABLE COLUMN FOR DEEP CONVECTION SUGGESTS A
FORECAST FOR LOWER RAIN CHANCES THAN HAS BEEN THE NORM THIS SUMMER
SEASON. THE SURFACE RIDGE TO OUR NORTH WILL BE STRENGTHENING AND
ALLOWING A WELL-DEFINED EASTERLY FLOW TO DEVELOP. THIS EASTERLY FLOW
WOULD NORMALLY BE ASSOCIATED WITH HIGH RAIN CHANCES AS IT FAVORS
CONVECTIVE FOCUS ALONG THE FLORIDA WEST COAST. THE EASTERLY FLOW
SHOULD HELP TO OVERCOME SOME OF THE NEGATIVE FACTORS FOR
CONVECTION...HOWEVER THE DRY AIR WILL BE SIGNIFICANT ENOUGH TO KEEP
POPS WELL BELOW CLIMO NORMS FOR THIS FLOW PATTERN. MONDAY AFTERNOON
RAIN CHANCES WILL SHOW 20% FOR I-4 NORTHWARD AND 30% FURTHER SOUTH.
BY TUESDAY...A SLIGHT MOISTENING BRINGS THE 30% POPS NORTHWARD TO
TAMPA BAY AND MUCH OF THE NATURE COAST. THE STORMS MONDAY AND
TUESDAY SHOULD BE WIDELY SCT IN NATURE AND ALSO BRIEF IN LIFECYLE AS
THEY CONTINUE TO FIGHT THE HOSTILE ENTRAINMENT OF LOW THETA-E AIR.
&&
.LONG TERM (WEDNESDAY THROUGH NEXT SATURDAY)...
WE WILL REMAIN IN DEEP EASTERLY FLOW THROUGH THE EXTENDED PERIOD AS
HIGH PRESSURE HOLDS FIRM TO OUR NORTH. BOTH THE GFS AND THE ECMWF
CARVE OUT A SOMEWHAT DEEPER TROUGH OVER THE NORTHEAST ON
FRIDAY...BUT A NARROW RIDGE OF HIGH PRESSURE SEPARATES FLORIDA FROM
THIS TROUGH.
MOISTURE WILL BEGIN TO RETURN ON WEDNESDAY FOLLOWING A FEW DRIER
THAN NORMAL DAYS. RAIN CHANCES WILL BE CLOSE TO CLIMATIC NORMALS
WITH 30 PERCENT NORTH TO NEAR 50 PERCENT SOUTH.
MODELS AGREE ON A MID-LEVEL DISTURBANCE AND ASSOCIATED SURFACE
TROUGH/TROPICAL WAVE MOVING ACROSS THE STATE WEDNESDAY NIGHT OR
THURSDAY. THE GFS BRINGS PRECIPITABLE WATERS BACK INTO THE 1.9 TO
2.1 INCH RANGE BEHIND THE WAVE THURSDAY AFTERNOON. THIS SHOULD BE
ENOUGH TO BRING RAIN CHANCES BACK UP INTO THE GOOD CHANCE TO LIKELY
CATEGORY...BUT SINCE THE ECMWF IS NOT QUITE AS WET I WILL HOLD RAIN
CHANCES TO ABOUT 50 PERCENT.
FRIDAY AND SATURDAY SHOULD SEE TYPICAL WET-SEASON CONDITIONS WITH
NEAR OR ABOVE-NORMAL RAIN CHANCES EACH AFTERNOON AS EASTERLY FLOW
CLASHES WITH THE SEA BREEZE NEAR THE COAST.
&&
.AVIATION...
VFR CONDITIONS NEXT 24 HOURS. DRIER AIR WILL LIMIT/DELAY
THUNDERSTORM DEVELOPMENT THIS AFTERNOON BUT STILL MAY SEE BRIEF
IMPACTS AROUND PGD...FMY AND RSW.
&&
.MARINE...
A WEAK RIDGE OF HIGH PRESSURE TO THE NORTH OF THE REGION WILL
STRENGTHEN THROUGH THE EARLY PORTION OF THE WEEK...HELPING TO KEEP
AN EASTERLY FLOW PATTERN IN PLACE OVER THE EASTERN GULF OF MEXICO.
THE RIDGE POSITION AND STRENGTH WILL BE SUPPORTIVE OF NOCTURNAL
EASTERLY WIND SURGES MONDAY NIGHT AND TUESDAY NIGHT THAT MAY
APPROACH OR REACH CAUTIONARY LEVELS...ESPECIALLY AWAY FROM THE
COAST.
&&
.FIRE WEATHER...
A WEAK RIDGE OF HIGH PRESSURE TO THE NORTH OF THE FORECAST AREA
TODAY WILL STRENGTHEN THROUGH THE EARLY PORTION OF THE WEEK...
HELPING TO KEEP AN EASTERLY FLOW PATTERN IN PLACE. A DRIER AIRMASS
THAN HAS BEEN EXPERIENCED LATELY IS EXPECTED THE NEXT SEVERAL DAYS
KEEPING RAIN CHANCES DOWN. THE BEST CHANCES TODAY AND MONDAY TO SEE
THE SCATTERED STORMS WILL BE SOUTH OF THE TAMPA BAY AREA. ALTHOUGH
CONDITIONS WILL BE DRIER...NO CRITICALLY LOW RELATIVE HUMIDITY IS
EXPECTED...AND NO SIGNIFICANT FIRE WEATHER CONCERNS ARE IN THE
FORECAST.
FOG POTENTIAL...PATCHY SHALLOW GROUND FOG WILL BE POSSIBLE EACH
MORNING AROUND SUNRISE IN THE NORMALLY FOG PRONE LOCATIONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 91 74 92 75 / 20 10 20 10
FMY 91 72 92 75 / 50 20 30 20
GIF 92 71 93 73 / 20 10 20 10
SRQ 90 73 93 74 / 30 20 30 20
BKV 92 68 93 70 / 20 10 20 10
SPG 91 78 91 78 / 20 10 20 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS MIAMI FL
157 AM EDT SUN SEP 8 2013
.AVIATION...
MAINLY VFR CONDITIONS ARE EXPECTED FOR ALL SOUTH FLORIDA TERMINALS
DURING THE EARLY MORNING HOURS. HOWEVER...THERE ARE SOME LINGERING
BOUNDARIES ACROSS THE NEAR SHORE ATLANTIC WATERS. THAT IN
COMBINATION WITH PERSISTENT SHOWERS IN THE NEAR SHORE WATERS EAST
OF TERMINALS KFXE AND KFLL COULD ALLOW FOR ADDITIONAL SHOWER AND
ISOLATED THUNDERSTORM DEVELOPMENT THAT COULD AFFECT THE EAST COAST
TERMINALS LATER THIS MORNING...BUT ONLY BRIEF PERIODS OF SUB-VFR
CONDITIONS ARE EXPECTED.
60
&&
.PREV DISCUSSION... /ISSUED 1013 PM EDT SAT SEP 7 2013/
UPDATE...
LATEST SURFACE ANALYSIS SHOWS WEAK CONVERGENCE BOUNDARY ACROSS THE AREA
WHICH WAS THE MAIN FOCUS OF CONVECTION EARLIER MAINLY AROUND THE LAKE
OKEECHOBEE REGION. ACTIVITY HAS STEADILY DECREASED OVER THE PAST FEW
HOURS. 00Z SNDG AND AIRCRAFT DATA SHOW LIGHT LOW LEVEL EASTERLY FLOW
WITH CONSENSUS BETWEEN HRRR AND OTHER HIGH RES LOCAL MODELS BEING BEST
CHANCES OF OVERNIGHT SCATTERED ACTIVITY WILL LIKELY BE ATLANTIC WATERS
DUE TO INTERACTION BETWEEN AFOREMENTIONED BOUNDARY, THE LOW LEVEL FLOW,
AND A LIGHT OFFSHORE DRAINAGE FLOW ALONG THE EAST COAST. THERE IS ALSO
A CHANCE OF SUCH ACTIVITY ACROSS THE GULF WATERS BUT THE CHANCE IS LESS
DUE TO LACK OF OPPOSING LOW LEVEL AND DRAINAGE FLOWS. PRESENCE OF BOUNDARY,
VERY LIGHT LOW LEVEL WINDS, CALM AT THE SURFACE, HIGH ANTECEDENT MOISTURE,
AND DECREASING CLOUDS OVERNIGHT WILL LIKELY RESULT IN PATCHY GROUND
FOG ACROSS PORTIONS OF THE INTERIOR. FORECASTS HAVE ALL BEEN UPDATED
ACCORDINGLY.
PREV DISCUSSION... /ISSUED 746 PM EDT SAT SEP 7 2013/
AVIATION...
OUTSIDE OF SOME LINGERING LIGHT TO MODERATE RAIN WELL INLAND OF
THE TAF SITES THIS EVENING...CONDITIONS REMAIN QUIET WITH VFR
PREVAILING. THIS IS EXPECTED TO PERSIST THROUGH THE NIGHT AND INTO
SUNDAY. SIMILAR TO THIS MORNING...A FEW SHOWERS AND STORMS
SPREADING ASHORE ALONG THE EAST COAST WILL REMAIN POSSIBLE...WHICH
COULD IMPACT THE EAST COAST TERMINALS. THE LOW-LEVEL FLOW UNDER
10 KFT IS FORECAST TO REMAIN LIGHT THROUGH THE DAY SUNDAY...WHICH
WILL MOST LIKELY TRANSLATE TO SLOW MOVING STORMS. AS A
RESULT...WILL INCLUDE VCTS FROM 12Z ON FOR THE EAST COAST SITES
DUE TO THE POTENTIAL MORNING ACTIVITY AND VERY LITTLE STORM MOTION
EXPECTED. THE LATEST MODEL REFLECTIVITIES ARE MAINLY INDICATING
ISOLATED COVERAGE THROUGH SUNDAY.
PREV DISCUSSION... /ISSUED 244 PM EDT SAT SEP 7 2013/
SHORT TERM...
A TROUGH OF LOW PRESSURE OVER CENTRAL FLORIDA WILL CONTINUE TO
MOVE SLOWLY SOUTH TO LAKE OKEECHOBEE BY THIS EVENING...AND REMAIN
NEARLY STATIONARY TONIGHT INTO SUNDAY. THIS WILL KEEP A VERY LIGHT
NORTHEAST STEERING FLOW OVER SOUTH FLORIDA THIS AFTERNOON...BEFORE
GOING CLOSE TO NO STEERING FLOW TONIGHT INTO SUNDAY.
SO THE SHOWERS AND THUNDERSTORMS OVER THE NORTHERN AREAS OF SOUTH
FLORIDA EARLY THIS AFTERNOON WILL DRIFT TO THE SOUTHWEST THROUGH
THE AFTERNOON HOURS BEFORE DISSIPATING THIS EVENING. THESE SHOWERS
AND THUNDERSTORMS WILL ALSO LEAVE AN OUTFLOW BOUNDARY OVER THE
EAST COAST METRO AREAS TONIGHT WHICH COULD HELP TO GENERATE SOME
SHOWERS AND EVEN A FEW STORMS LATE TONIGHT INTO EARLY SUNDAY
MORNING. THEREFORE...THE POPS WILL REMAIN IN THE SCATTERED TO
LIKELY RANGE FOR THIS AFTERNOON OVER THE NORTHERN AREAS TAPERING
DOWN TO LOW END SCATTERED OVER THE SOUTHERN AREAS. THE POPS WILL
THEN DROP TO A SLIGHT 10 PERCENT FOR OVER MOST OF THE AREA FOR
LATE TONIGHT...EXCEPT 20 TO 30 PERCENT OVER THE EAST COAST METRO
AREAS.
WITH NO STEERING FLOW ON SUNDAY OVER SOUTH FLORIDA...THE SHOWERS
AND THUNDERSTORMS WILL MOVE VERY SLOWLY INLAND AS THE WEST AND
EAST COAST SEA BREEZES PUSHES INLAND SLOWLY. SO WILL UP THE POPS
OVER THE AREA FOR SUNDAY TO SCATTERED FOR THE METRO AREAS TO
LIKELY OVER THE INTERIOR AREAS.
THERE COULD ALSO BE SOME FOG OVER THE INTERIOR AND WEST COAST
METRO AREAS LATE TONIGHT AND AGAIN LATE SUNDAY NIGHT...AS THE
WINDS WILL BE CALM ALONG WITH THE LOW LEVEL MOISTURE IN PLACE. SO
WILL ADDED PATCHY FOG FOR THE INTERIOR AND WEST COAST METRO AREAS
FOR LATE TONIGHT AND AGAIN LATE SUNDAY NIGHT.
THE TROUGH OF LOW PRESSURE OVER LAKE OKEECHOBEE WILL THEN WASH OUT
ON MONDAY...AS HIGH PRESSURE STARTS TO BUILD BACK INTO CENTRAL
FLORIDA FROM THE WESTERN ATLANTIC WATERS. THIS WILL ALLOW FOR THE
STEERING FLOW TO BECOME A LITTLE BIT MORE EASTERLY ON MONDAY...AND
ALLOW EAST COAST SEA BREEZE TO PUSH INLAND A LITTLE BIT QUICKER.
SO THE BEST COVERAGE OF SHOWERS AND THUNDERSTORMS ON MONDAY WILL
BE MORE OVER THE INTERIOR AND WEST COAST METRO AREAS.
LONG TERM...
THE RIDGE OF HIGH PRESSURE WILL CONTINUE TO BUILD INTO CENTRAL
FLORIDA MIDDLE TO END OF NEXT WEEK DEEPENING THE EASTERLY WIND FLOW
OVER SOUTH FLORIDA. SO THE BEST AREAS THAT WILL SEE THE SCATTERED
SHOWERS AND THUNDERSTORMS SHOULD BE OVER THE INTERIOR AND WEST
COAST METRO AREAS EACH DAY.
AVIATION...
A WEAK TROUGH HAS ENHANCED THE INSTABILITY OVER SOUTH FLORIDA,
BRINGING NUMEROUS CONVECTIVE SHOWERS AND THUNDERSTORMS. THIS HAS
MADE FOR A TRICKY AVIATION FORECAST. FOR NOW, HAVE KEPT MOST OF
THE ACTIVITY IN THE NORTHERN AREAS, NEAR KPBI AND KFXE, THEN BRING
IT A LITTLE FURTHER SOUTH MID AFTERNOON. ALSO, THE GULF SHOULD
BEGIN TO DEVELOP CONVECTION NEAR KAPF IN THE NEXT COUPLE OF HOURS.
MODELS ARE INDICATING THAT THIS MORNINGS ACTIVITY MAY INHIBIT
CONVECTION FURTHER SOUTH, AT KMIA AND KTMB. SO FOR NOW, JUST HAVE
VCSH AT THOSE SITES. HOWEVER, CONDITIONS COULD CHANGE AND EVEN
THOSE SITES MAY NEED VCTS ADDED THIS AFTERNOON. CONVECTION ALONG
THE ATLANTIC COAST SHOULD MOVE OFF INTO THE INTERIOR PORTIONS,
AWAY FORM THE TAF SITES, AROUND 00Z. TOMORROW COULD SEE ANOTHER
ROUND OF AFTERNOON CONVECTION.
MARINE...
THE WINDS WILL BE NORTHEAST AT 10 KNOTS OR LESS OVER ALL OF THE
LOCAL WATERS OF SOUTH FLORIDA THROUGH MONDAY...BEFORE SWINGING TO
A EASTERLY DIRECTION AND INCREASING TO AROUND 15 KNOTS MIDDLE OF
NEXT WEEK. THIS WILL ALLOW FOR THE SEAS TO REMAIN AT OR BELOW 2
FEET IN BOTH THE ATLANTIC AND GULF WATERS OF SOUTH FLORIDA THROUGH
MONDAY...BEFORE SLOWLY INCREASING TO 2 TO 4 FEET IN THE ATLANTIC
WATERS OF SOUTH FLORIDA BY MIDDLE OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 88 75 88 77 / 40 30 30 20
FORT LAUDERDALE 88 77 88 79 / 40 20 30 20
MIAMI 89 76 89 78 / 50 30 40 20
NAPLES 90 73 92 74 / 50 20 40 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...23/SK
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1253 AM CDT SUN SEP 8 2013
.DISCUSSION...
748 PM CDT
FOR EVENING UPDATE...
HAVE MADE SOME SIGNIFICANT CHANGES TO LOWER POPS/DECREASE COVERAGE
OF SHOWER/THUNDERSTORM CHANCES THIS EVENING AND OVERNIGHT.
CONVECTION HAS STRUGGLED ACROSS THE CWA SINCE LATE THIS
AFTERNOON...LIKELY DUE TO WEAK CONVERGENCE AND RELATIVELY DRY LOW
LEVEL AIR MASS AND PERSISTENT CAP NOTED BETWEEN 800-850MB IN BOTH
ILX/DVN 00Z SOUNDINGS. COLD FRONT REMAINS NORTH/WEST OF THE AREA
AT 01Z...AND WILL SINK ACROSS THE AREA OVERNIGHT...THOUGH
DECREASING DIURNAL INSTABILITY WILL MOST LIKELY LIMIT POTENTIAL
FOR ADDITIONAL SIGNIFICANT SHOWER/THUNDERSTORM DEVELOPMENT
DESPITE HIGH-RES CONVECTIVE ALLOWING GUIDANCE CONTINUING TO
DEPICT POTENTIAL FOR MORE STORMS TO FORM. SPC/RAP MESOANALYSIS
INDICATES STRONGER INSTABILITY/WEAKER CAPPING REMAINS ACROSS
NORTHEAST IA...THUS HAVE MAINTAINED CHANCE POPS MAINLY ACROSS
WEST/SOUTH PARTS OF CWA SIMILAR TO EARLIER THINKING...WHILE
LOWERING TO ISOLATED OR NONE FARTHER EAST/NORTHEAST.
FRONT WILL SLIP IN LATE TONIGHT...WITH INCREASING NORTHEAST WINDS
BY MORNING AS SURFACE HIGH PRESSURE BUILDS SOUTHEAST ACROSS THE
LAKES.
RATZER
//PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH TUESDAY...
FORECAST CONCERNS INCLUDE SHRA/TSRA CHANCES THIS EVENING INTO
TONIGHT AND THEN A BLAST OF LATE SEASON HEAT MONDAY INTO TUESDAY.
THE PRIMARY CONCERN IN THE NEAR TERM IS WITH SHOWER AND THUNDER
CHANCES THROUGH THIS EVENING. A COLD FRONT IS SLOWLY SINKING SOUTH
FROM SOUTHERN WISCONSIN AND A PEAK AT WATER VAPOR IMAGERY SHOWS
DISTURBED MODERATE NW FLOW ALOFT WITH A SHORT WAVE PUSHING SOUTHEAST
ACROSS THE UPPER MS VALLEY. HI-RES GUIDANCE SUCH AS THE HRRR INSISTS
ON CONVECTION LATER THIS AFTERNOON AND THIS EVENING. ALSO MOST
GUIDANCE FAVORED THE IDEA OF BETTER MOISTURE CONVERGENCE FOCUSING
THIS EVENING OVER THE WEST/SW CWA AND POINTS SW ALONG SWD MOVING
COLD FRONT AND A WEAK SURFACE WAVE STRETCHING ACROSS THE MID MS
VALLEY. HOWEVER...GIVEN LACK OF AGITATED CU UPSTREAM OVER WISCONSIN
AND NORTHEAST IOWA...CONFIDENCE IN THIS SCENARIO IS LOW AND WILL
MAKE A LAST MINUTE DECISION ON POPS BEFORE PUBLISHING GRIDS. HAD
INDICATED HIGH CHANCE RANGE POPS EARLY FOR THE NORTH HALF SHIFTING
INTO THE SW CWA LATER THIS EVENING...BUT CURRENT THINKING IS THESE
POPS MAY BE TOO HIGH.
ONCE THE COLD FRONT FINALLY DOES PUSH THROUGH MOST OF THE CWA LATE
TONIGHT...GUSTY NORTHEAST FLOW WILL DEVELOP OVER THE LAKE AND LOW
CLOUDS ARE EXPECTED TO DEVELOP. BASED ON FORECAST SOUNDINGS AND LOW
LEVEL RH ON THE MODELS...THESE LOW CLOUDS SHOULD HANG
ON...ESPECIALLY FOR THE NORTHERN CWA INTO THE EARLY AFTERNOON BEFORE
FINALLY ERODING. THE COOLER AIR MASS...CLOUD COVER AND NORTHEAST
FLOW WILL RESULT IN TEMPERATURES ONLY IN THE 70S/POSSIBLY LOW 70S
NEAR LAKE MICHIGAN NORTH OF I-80 AND LOW-MID 80S SOUTH WHERE CLOUDS
MAY ERODE QUICKER AND WARMER THERMAL PROFILES EXIST. CONCERNED THAT
STALLING COLD FRONT COULD SERVE AS A FOCUS FOR SPOTTY TSRA
DEVELOPMENT IN THE SRN CWA SO BUMPED UP POPS A BIT. ALSO...IN
DISTURBED NW FLOW...MODELS EVEN GENERATING QPF FARTHER NORTH...BUT
MAINTAINED A DRY FORECAST FOR NOW.
VERY STRONG WARM ADVECTION WILL ENSUE ALOFT TOMORROW NIGHT AS HOT
AIR MASS OVER THE PLAINS RUSHES EASTWARD IN RESPONSE TO STRONG LOW
PRESSURE OVER THE NORTHERN PLAINS LIFTING NORTHEAST. THE LOW
PRESSURE AREA WILL LIFT THE FRONT STALLED TO OUR SOUTH BACK NORTH AS
A WARM FRONT ON MONDAY. ANY EARLY MORNING CLOUDS OVER THE NORTHEAST
HALF OF CWA WILL SHIFT NORTHEAST BY LATE MORNING. MODEL THERMAL
PROFILES HAVE COME IN VERY WARM/IE 850 MB TEMPS AROUND 20C AND 925
MB TEMPS IN THE MID TO UPPER 20SC BY LATE DAY. THUS TRENDED HIGHS A
FEW DEGREES WARMER THAN PREVIOUS FORECAST. A VERY WARM NIGHT FOR
SEPTEMBER IS THEN IN STORE ON MONDAY NIGHT...MAYBE NOT DROPPING OUT
OF THE UPPER 70S IN DOWNTOWN CHICAGO. THIS WILL PROVIDE A
SPRINGBOARD FOR POTENTIAL RECORD/NEAR RECORD WARMTH ON TUESDAY.
GUSTY SOUTHWEST FLOW AND DEEP MIXING OF LOW 20S AT 850 AND UPPER 20S
AT 925 MB AIRMASS WILL SUPPORT HIGHS SOLIDLY INTO THE MIDDLE 90S FOR
MOST OF THE AREA...IF NOT WARMER FOR A FEW SPOTS. A COLD FRONT WILL
BE SAGGING SOUTH AND IS A WILD CARD FOR TEMPS IN THE NORTHERN CWA
BUT WITH SUCH A HOT AIR MASS...CONTINUE TO FAVOR THE IDEA OF FRONTAL
PASSAGE DURING THE EVENING...WHICH WILL KEEP CLOUDS AND THUNDER
CHANCES MAINLY IN THE EVENING. AS ALLUDED TO YESTERDAY...THE SAVING
GRACE FOR THIS LATE SEASON HEAT WILL BE FAIRLY DRY CONDITIONS/TD
ONLY IN THE LOW-MID 60S.
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY...
MAINTAINED BLENDED GUIDANCE FOR MID-HIGH CHANCE POPS TUESDAY
EVENING/NIGHT WITH COLD FRONT BUT IF FRONT SLOWS
FURTHER...INSTABILITY MAY WANE ENOUGH TO GREATLY LIMIT COVERAGE OF
SHRA/TSRA. THEN ON WEDNESDAY...THE FRONT WILL STILL BE DROPPING
SOUTHWARD...KEEPING A CHANCE FOR THUNDER GOING. AIR MASS WILL ONLY
BE MODESTLY COOLER INITIALLY. THEN A MUCH COOLER AIRMASS WILL
FINALLY ARRIVE THURSDAY INTO FRIDAY AS EASTERN NOAM TROUGH DEEPENS
AND BRUSHES OUR AREA WHILE STRONG CANADIAN HIGH PRESSURE SPREADS
SOUTHWARD. 850 MB THERMAL TROUGH LOOKS TO ARRIVE THURSDAY NIGHT INTO
FRIDAY...WITH MID TO HIGH SINGLE DIGITS AT 850 MB. SO AFTER A COOLER
BUT BASICALLY SEASONABLE THURSDAY...FRIDAY WILL BE A TASTE OF AUTUMN
WITH HIGHS ONLY IN THE LOW-MID 70S AWAY FROM LAKE MICHIGAN AND
MID-UPPER 60S ON THE LAKEFRONT. HEIGHT RISES WILL QUICKLY RETURN
SATURDAY SO TEMPERATURES WILL WARM SLIGHTLY.
RC
&&
.CLIMATE...
653 PM CDT
RECORD WARMTH FOR SEPTEMBER 10TH IS POSSIBLE ON TUESDAY:
CHICAGO:
RECORD HIGH: 95 (1983)
RECORD WARM LOW: 75 (1912)
ROCKFORD:
RECORD HIGH: 96 (1931)
RECORD WARM LOW: 70 (2000)
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NNE WINDS TURNING NE THROUGH THE MORNING. GUSTS INTO THE TEENS
OVERNIGHT AND TO NEAR 20 KT AT TIMES DURING THE DAY.
* LOW END MVFR CIGS ARRIVING NEXT 1-2 HOURS AND MAY PERSIST
THROUGH THE MORNING. BRIEF IFR POSSIBLE.
MDB
//DISCUSSION...UPDATED 06Z...
COLD FRONT NOW MAKING IT THROUGH RFD AND GYY WITH WINDS TURNING
NORTH TO NORTHEAST BEHIND IT. AN INCREASE IN SPEEDS LAGS BEHIND
THE FRONT BUT UPSTREAM SITES IN WISCONSIN HAVE BEEN SEEING SOME
GUSTS INTO THE 15 TO 20 KT RANGE AND EXPECT THAT SOME GUSTINESS
WILL ARRIVE LOCALLY IN THE NEXT 1-2 HRS. GUSTS TO 20 KT LOOK MORE
LIKELY DURING THE DAY. SATELLITE SHOWS LOW END MVFR STRATUS...WITH
SOME EMBEDDED IFR...MOVING SOUTHWARD TOWARD THE TERMINALS AND HAVE
ADJUSTED TIMING OF ARRIVAL OF BKN MVFR CIGS AT THE TERMINALS. THE
MAIN CHALLENGE WILL BE TIMING THE SCATTERING/EXITING OF MVFR CIGS
TODAY. COVERAGE IS PRETTY EXTENSIVE FROM SOUTHEAST WI
NORTHEASTWARD INTO NORTHERN LOWER MICHIGAN. HAVE RETAINED THE 18Z
TIME FOR SCATTERING AS THIS LOOKS REASONABLE AND STRATUS MAY BEGIN
TO EXPAND WITH TIME OVERNIGHT FURTHER SUPPORTING A SLOW
IMPROVEMENT. IT DOES APPEAR THAT VFR WILL RETURN THIS AFTERNOON.
HIGH PRESSURE WILL PASS TO THE EAST OF THE AREA TONIGHT WHICH WILL
ALLOW WINDS TO SHIFT SOUTHEASTERLY THIS EVENING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN LOW END MVFR ARRIVING NEXT FEW HOURS...MEDIUM
CONFIDENCE IN HOW QUICKLY IT WILL SCATTER/DEPART.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY THROUGH TUESDAY...VFR.
TUESDAY NIGHT AND WEDNESDAY...CHANCE TSRA WITH MVFR POSSIBLE.
THURSDAY THROUGH FRIDAY...VFR.
RATZER
&&
.MARINE...
129 PM CDT
A COLD FRONT IS BEGINNING TO MOVE ACROSS THE NORTHERN PORTION OF
LAKE MICHIGAN EARLY THIS AFTERNOON. THIS FRONT WILL SWEEP DOWN THE
LAKE INTO THIS EVENING...WITH WINDS RAPIDLY SHIFTING OUT OF THE
NORTH-NORTHEAST IN ITS WAKE. IT STILL APPEARS THAT A PERIOD OF 15 TO
25 KT WINDS WILL SET ACROSS THE LAKE TONIGHT INTO SUNDAY WITH A
DECENT PRESSURE GRADIENT AHEAD OF A SURFACE HIGH BUILDING
SOUTHEASTWARD FROM ONTARIO. THIS LOOKS TO SET UP HAZARDOUS
CONDITIONS FOR SMALL CRAFT...WITH WAVES UP TO 7 FEET...MAINLY FOR
THE NORTHEAST ILLINOIS SHORES. WITH THIS IN MIND I ISSUED A SMALL
CRAFT ADVISORY LATE SATURDAY NIGHT THROUGH SUNDAY EVENING FOR ALL
BUT THE PORTER INDIANA NEAR SHORE ZONE...WHERE SLIGHTLY LOWER WAVES
ARE EXPECTED.
THE WINDS ARE EXPECTED TO VEER TO THE EAST-SOUTHEAST
SUNDAY NIGHT INTO MONDAY AS THE SURFACE HIGH SHIFTS FROM THE UPPER
GREAT LAKES ACROSS THE NORTHEASTERN U.S. THIS COULD LEAD TO A
CONTINUATION OF NEAR 4 FOOT WAVES INTO MONDAY FOR THE ILLINOIS
SHORES. THIS COULD RESULT IN THE SMALL CRAFT ADVISORY NEEDING TO BE
EXTENDED...BUT DUE TO THE MARGINAL WAVE MAGNITUDES...I WILL HOLD OFF
ON EXTENDING THE ADVISORY INTO THIS PERIOD.
THE WINDS SHOULD BECOME SOUTHERLY AGAIN BY MONDAY...BUT SPEEDS WILL
LIKELY REMAIN FAIRLY HIGH...25 TO 30 KT...AS A POTENT AREA OF LOW
PRESSURE MOVES EAST-NORTHEASTWARD ACROSS THE DAKOTAS AND MINNESOTA.
LATER IN THE WEEK...IT APPEARS THAT A POTENT COLD FRONT COULD DROP
ACROSS THE LAKE...LEADING TO SOME STRONGER NORTHERLY WINDS.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...4 AM SUNDAY TO 11 PM
SUNDAY.
IN...BEACH HAZARDS STATEMENT...INZ001...4 AM SUNDAY TO 11 PM SUNDAY.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741...4 AM SUNDAY TO 11 PM
SUNDAY.
SMALL CRAFT ADVISORY...LMZ742-LMZ743-LMZ744...10 AM SUNDAY TO 11
PM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS DES MOINES IA
630 PM CDT MON SEP 9 2013
.SHORT TERM.../TONIGHT /...
ISSUED AT 324 PM CDT MON SEP 9 2013
MAIN FORECAST CONCERN IS WITH WEAK FRONT EXPECTED TO DIP INTO FAR
NORTHERN IOWA OVERNIGHT TONIGHT. LATEST HOPWRF SUGGEST SOME WEAK
ISOLATED DEVELOPMENT ALONG THE FRONT PAST 05Z TUESDAY IN SOUTHERN
MINNESOTA AND NORTHWEST IOWA. THE HRRR AND 4.0 SPC WRF SUGGEST
SIMILAR TREND...ALTHOUGH SLIGHTLY FURTHER NORTHWEST. THERE IS SOME
WEAK FRONTOGENETICAL FORCING BETWEEN 850MB AND 700MB LATER TONIGHT
INTO EARLY TUESDAY MORNING THAT SNEAKS INTO NORTHWEST IOWA. SO
KEPT SLIGHT POPS GOING ACROSS THE NORTH TONIGHT...BUT HAVE LOW
CONFIDENCE WITH ANY SIGNIFICANT RAINFALL SINCE SHOWERS WILL BE
VERY HIGH BASED. WENT CLOSER TO THE ECMWF FOR LOW TEMPS TONIGHT
WITH THE WAA CONTINUING AHEAD OF THE FRONT.
.LONG TERM.../TUESDAY THROUGH MONDAY/...
ISSUED AT 324 PM CDT MON SEP 9 2013
MAIN FORECAST CONCERNS FOR TUESDAY INT WEDNESDAY REVOLVE AROUND A
COLD FRONTAL PASSAGE. MOST OF THE FORCING WITH THE FRONT SHIFTS
NORTH AND EAST OF THE AREA. WHILE DEEP SHEAR IS UNIMPRESSIVE THERE
IS SOME LOW LEVEL SHEAR COINCIDENT WITH THE FRONT. MODELS CONTINUE
TO SHOW LITTLE IN THE WAY OF RAINFALL AND THAT BEING POST FRONTAL.
THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL COME LATE
AFTERNOON AND EVENING WHEN A SHORT WAVE MOVES ACROSS MAINLY THE
NORTHERN FORECAST AREA AND INTERACTS WITH THE FRONT. SOUNDINGS
SHOW STEEP LAPSE RATES SO WHILE ANY STORMS WOULD BE ISOLATED TO
SCATTERED AT BEST THERE IS SOME POTENTIAL FOR AN ISOLATED WIND
THREAT. THE HEAT WILL STILL BE ON FOR SOUTHEAST PORTIONS OF THE
STATE TOMORROW AND THERE IS SOME CONCERN THAT WITH TWO WARM NIGHTS
NOW AND WHAT WILL BE THE SECOND HOT DAY THERE COULD BE SOME
CUMULATIVE EFFECTS OF PROLONGED HEAT. HOWEVER WITH LONGER NIGHTS
THERE SHOULD BE MORE TIME FOR THE BODY TO RECOVER SO WE WILL
CONTINUE TO HANDLE THE HEAT WITH A SPECIAL WEATHER STATEMENT.
THE FRONT GRADUALLY SHIFTS TO THE SOUTH THROUGH WEDNESDAY FOLLOWED
BY COOLER TEMPS FOR THE REST OF THE WEEK.
FOR THE WEEKEND THE MODELS SUGGEST A SHORTWAVE PUSHING ACROSS THE
NORTHERN PLAINS AGAIN AND POSSIBLY INTO THE UPPER MIDWEST. TIMING
AND STRENGTH OF THE SHORTWAVE ARE STILL IN QUESTION BUT THERE
APPEAR TO BE AT LEAST CHANCES FOR THUNDERSTORMS AND GRIDS CONTINUE
TO REFLECT THESE CHANCES.
&&
.AVIATION...10/00Z
ISSUED AT 630 PM CDT MON SEP 9 2013
A WEAK FRONT WILL PUSH INTO NORTHERN IOWA LATE TONIGHT AND MAKE
ONLY SLOW PROGRESS SOUTHWARD ON TUESDAY. CONDITIONS WILL REMAIN
VFR ACROSS THE ENTIRE FORECAST AREA FOR THE DURATION OF THE
FORECAST. WINDS WILL BE LIGHT NEAR THE FRONT BUT IN CENTRAL AND
SOUTHERN IOWA...WINDS WILL BE GUSTY FROM THE SOUTHWEST ONCE AGAIN
ON TUESDAY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...FAB/PODRAZIK
LONG TERM...FAB
AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
332 PM CDT SUN SEP 8 2013
.SYNOPSIS...
ISSUED AT 330 PM CDT SUN SEP 8 2013
A STATIONARY FRONT WAS DRAPED ACROSS THE FAR SOUTHERN CWA EARLY THIS
AFTERNOON. WIDESPREAD STRATUS NORTH OF THE FRONT HAS BEEN SLOWLY
ERODING AND LIFTING NORTH... WITH THE MOST EXTENSIVE STRATUS NEAR
AND NORTH OF HWY 20 WHILE ELSEWHERE THE STRATUS HAS EVOLVED INTO
SCT-BKN STRATOCU DECK. WHERE THE STRATUS HAS BEEN SOLID AND LINGERED
ALL DAY NORTH OF HWY 30 TEMPS HAVE BEEN HELD DOWN INTO THE 70S IN
MANY AREAS... WHILE TO THE SOUTH WITH SOME SOLAR INSOLATION TEMPS
HAVE WARMED INTO THE 80S WITH A FEW SITES IN THE UPPER 80S OVER THE
FAR SOUTHERN CWA. MOISTURE WAS POOLING NEAR THE BOUNDARY WITH DEWPTS
IN THE UPPER 60S AND LOWER 70S MAKING FOR RATHER HUMID CONDITIONS
THOUGH BEING OFFSET AT TIMES BY GUSTY EASTERLY WINDS. THE PATTERN
ALOFT FEATURES LARGE HEAT DOME CENTERED OVER KANSAS... WITH NORTHWEST
FLOW OVER OUR AREA. AN UPPER LEVEL DISTURBANCE WHICH BROUGHT
AREAS OF SIGNIFICANT RAINFALL OF 2-4+ INCHES TO PORTIONS OF WEST
CENTRAL ILLINOIS LATE LAST NIGHT WAS PASSING SOUTH NEAR THE ST LOUIS
METRO ATTM. ANOTHER DISTURBANCE WAS SEEN TOPPING THE UPPER LEVEL RIDGE
AND SLIDING E/SE FROM DAKOTAS THROUGH MINNESOTA.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 330 PM CDT SUN SEP 8 2013
HEAT AND HUMIDITY AND NEED FOR HEADLINES MONDAY IS THE MAIN CONCERN.
STATIONARY FRONT TO LIFT BACK NORTH AS WARM FRONT OVERNIGHT THROUGH
MONDAY MORNING. RAIN CHANCES ARE NOT ZERO TONIGHT BUT LACK OF
COHERENT TRIGGER WITH ONLY WEAK WARM ADVECTION/ISENTROPIC LIFT WOULD
SUGGEST ANY ACTIVITY FAR TOO SPARSE IN COVERAGE TO WARRANT ANY MENTION.
EXPECT TO SEE CONTINUED DECREASE IN STRATUS THROUGH SUNSET THEN WITH
MOISTURE POOLING WOULD ANTICIPATE ADDITIONAL LOW CLOUD AND SOME FOG
DEVELOPMENT OVERNIGHT INTO EARLY MONDAY MORNING AHEAD OF THE WARM
FRONT. THINKING ANY FOG MOSTLY AVIATION CONCERN BUT CANT RULE OUT SOME
DENSE FOG GIVEN THE ABUNDANT LOW LEVEL MOISTURE AND WILL NEED TO BE
MONITORED. STAYED WITH BLEND OR WARM SIDE FOR LOWS WITH RANGE FROM THE
MID 60S TO SOME LOWER 70S. WARM FRONT TO LIFT NORTH OF THE CWA BY MONDAY
AFTERNOON. THIS WILL SET THE STAGE FOR VERY WARM TO HOT AFTERNOON WITH
MODELS SHOWING 850 MB TEMPS CLIMBING TO AROUND 22-24C. MIXING TO THE
SURFACE YIELDS MAX TEMPS OF ROUGHLY 92-98F WITH WARMEST READINGS ACROSS
THE SOUTHWEST 1/3-2/3 OF CWA. DEWPTS WILL START OUT IN THE UPPER 60S
TO LOWER 70S BUT WITH MIXING AND DRYING FROM ALOFT ANTICIPATE LOWERING
INTO THE LOWER TO MIDDLE 60S DURING PEAK HEATING. THIS WOULD PUT HEAT
INDICES IN THE RANGE OF AROUND 94-99F OR MAINLY JUST BELOW ADVISORY
CRITERIA. HAVE HELD OFF THEN ON HEAT ADVISORY AND WILL CONTINUE TO
HIGHLIGHT IN HWO AND WX STORY. SOME FIRE WX CONCERNS BUT FUELS NOT THERE
YET FOR HEADLINES. BUT... GIVEN HOW DRY IT HAS BEEN AND POTENTIAL
OF SOME GUSTY WINDS IN THE AFTERNOON IT COULD BE DIFFICULT CONTROLLING
ANY FIRES IN THE RIGHT FUELS WITH DITCHES BEING OF MOST CONCERN AND
PLAN TO MENTION IN HAZARDOUS WEATHER OUTLOOK.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 PM CDT SUN SEP 8 2013
BREAKDOWN OF THE UPPER LEVEL HIGH AND CHANGE TO A NW FLOW ALOFT WILL
RESULT IN COOLER...AND POSSIBLY EVEN BELOW NORMAL TEMPERATURES FOR
LATE WEEK INTO NEXT WEEKEND. CONDITIONS TO REMAIN DRY OUTSIDE OF
THUNDERSTORMS CHANCES WITH THE COLD FRONTAL PASSAGE THAT MARKS THIS
TRANSITION TUESDAY NIGHT INTO WED...AND ANOTHER COLD FRONT ON
SUNDAY.
MONDAY NIGHT AND TUESDAY...VERY WARM AIRMASS WILL BE IN PLACE AHEAD
OF THE LEAD COLD FRONT THAT BEGINS TO DROP SOUTH THROUGH THE AREA
TUESDAY AFTERNOON. LIGHT SOUTHWEST WINDS...PREFRONTAL COMPRESSIONAL
WARMING...AND LOW LEVEL MOISTURE CONVERGENCE SHOULD HOLD MINS IN THE
UPPER 60S AND LOWER 70S. TUESDAY...MODEL CONSENSUS HAS THE FRONT
DROPPING TO ROUGHLY THE HIGHWAY 30 CORRIDOR BY LATE AFTERNOON.
ANOTHER DAY OF DEEP MIXING INTO VERY WARM AIR ALOFT AHEAD OF THE
FRONT SHOULD PUSH HIGHS BACK INTO THE LOWER TO MID 90S SOUTH. IN THE
NORTH...WILL HAVE A SLIGHT CHANCE OF POST FRONTAL AFTERNOON
THUNDERSTORMS. BEFORE THE WEAK FRONTAL PASSAGE...TEMPERATURES SHOULD
REACH THE UPPER 80S TO LOWER 90S. LOW LEVEL MOISTURE POOLING WILL
HOLD DEWPOINTS IN THE LOWER TO MID 60S. THIS COMBINATION WILL RESULT
IN HEAT INDEX READINGS AS HIGH AS THE MID TO UPPER 90S IN THE
SOUTH...JUST BELOW ADVISORY CRITERIA.
WILL CONTINUE CHANCE POPS FOR SHOWERS AND THUNDERSTORMS AS THE
INITIAL COOL FRONT SLOWLY SAGS SOUTH THROUGH THE AREA. ADDITIONAL
WEAK FORCING WILL BE PROVIDED BY THE RIGHT ENTRANCE REGION TO AN
UPPER LEVEL JET MOVING THROUGH THE UPPER GREAT LAKES AND ONTARIO TUE
NIGHT...THEN AN UPPER LEVEL TROUGH DIGGING INTO SOUTHERN ONTARIO
WEDNESDAY. CLOUD COVER AND LINGERING RH WILL LIMIT LOWS TO THE MID
60S NORTH TO LOWER 70S SOUTH TUE NIGHT...WITH HIGHS THEN IN THE 80S
AT BEST WEDNESDAY.
NW FLOW THAT FOLLOWS AS THE UPPER LEVEL TROUGH DEVELOPS OVER EASTERN
CANADA WILL ALLOW COOLER AIR AT 850 MB AND SURFACE HIGH PRESSURE TO
DROP SOUTH INTO THE UPPER MS VALLEY AND GREAT LAKES THU AND FRI.
MODEL CONSENSUS HAS HIGHS LIMITED TO THE LOWER TO MID 80S THU...THEN
MAINLY 70S FRI INTO THE WEEKEND WHILE LOWS WILL BE MAINLY IN THE
50S. MINS IN THE 40S WILL BE POSSIBLE OVER ESPECIALLY THE NORTHEAST
FRIDAY NIGHT WHEN THE HIGH PRESSURE CENTER MAKES ITS CLOSEST PASS
OVER LOWER MI. THU THROUGH SATURDAY WILL BE ANOTHER DRY PERIOD...
FOLLOWED BY RAIN CHANCES ON SUNDAY...WHERE THE LATEST GFS AND ECMWF
HAVE COLD FRONTAL PASSAGE THAT WILL HAVE AN AXIS OF GULF MOISTURE
RETURN FLOW TO WORK WITH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1240 PM CDT SUN SEP 8 2013
NEARLY STATIONARY FRONTAL ZONE IS DRAPED OVER FAR SOUTHEAST IOWA AND
WEST CENTRAL ILLINOIS. FAIRLY WIDESPREAD STRATUS WITH MVFR CIGS WAS
NOTED NORTH OF THE FRONT IMPACTING ALL TERMINALS. ANTICIPATE THE
STRATUS AND MVFR CIGS TO LIFT TO VFR AND SCATTERING AT THE TERMINALS
FROM SOUTH TO NORTH THROUGH 00Z. STATIONARY FRONT IS EXPECTED TO
LIFT BACK NORTH AS A WARM FRONT THROUGH THE TERMINALS LATE TONIGHT
AND MONDAY MORNING. ANTICIPATE MORE LOW CLOUDS AND FOG WITH IFR TO
MVFR CONDITIONS DEVELOPING NORTH OF THE WARM FRONT AS SUGGESTED BY
MOST GUIDANCE INCLUDING HRRR...SREF AND RAP MODEL VSBY/CIG PLOTS.
CONDITIONS TO RETURN TO VFR AT ALL SITES BY 18Z MONDAY AS WARM FRONT
LIFTS NORTH OF THE TERMINALS. WINDS WILL BE EASTERLY AT 5-10 KTS
THIS AFTERNOON AND EVENING... WITH OCCASIONAL GUSTS NEAR 20 KTS POSSIBLE
THIS AFTERNOON. LATE TONIGHT AND MONDAY MORNING AS THE WARM FRONT PASSES
WINDS WILL BECOME SOUTHERLY AROUND 10 KTS WITH SOME GUSTS POSSIBLE LATE
MORNING. RAIN CHANCES ARE NOT ZERO DURING THE PERIOD... BUT APPEAR TOO
SMALL FOR INCLUSION IN TERMINALS.
&&
.CLIMATE...
ISSUED AT 235 PM CDT SUN SEP 8 2013
RECORD HIGHS FOR SEPTEMBER 9...
MOLINE.........99 IN 1933
CEDAR RAPIDS...98 IN 1955
DUBUQUE........97 IN 1955
BURLINGTON.....100 IN 1912
RECORD HIGHS FOR SEPTEMBER 10...
MOLINE.........95 IN 1983
CEDAR RAPIDS...98 IN 1931
DUBUQUE........97 IN 1895
BURLINGTON.....97 IN 1933
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...05
SHORT TERM...05
LONG TERM...SHEETS
AVIATION...05
CLIMATE...05
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1259 PM CDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 723 AM CDT SUN SEP 8 2013
THE CONVECTION HAS EXITED THE AREA AND A PERIOD OF QUIET WX IS
EXPECTED THROUGH THE EARLY AFTERNOON. PER THE RAP/WRF TRENDS THE
LOW CLOUDS COMING OFF LAKE MICHIGAN ARE MOVING JUST A BIT FASTER
THAN EXPECTED. HOWEVER...WITH THE SUN NOW UP THE SOUTHWARD
EXPANSION OF THE CLOUDS SHOULD BE HALTED. CLOUD COVER WILL MAKE
TEMPERATURES INTERESTING TODAY. THOSE AREAS THAT HAVE CLOUDS
SHOULD REMAIN IN THE UPPER 60S TO LOWER 70S FOR A GOOD PORTION OF
THE MORNING BEFORE RISING.
CONVECTION THIS AFTERNOON IS QUESTIONABLE. THERE IS A WARM LAYER
ALOFT THAT MAY PREVENT ANY CONVECTION FROM OCCURRING. IF
CONVECTION DOES OCCUR THE MOST LIKELY AREA WILL BE SOUTH OF I-80
WHERE THE STRONGER DIFFERENTIAL HEATING WILL OCCUR.
&&
.SYNOPSIS...
ISSUED AT 315 AM CDT SUN SEP 8 2013
06Z SFC ANALYSIS HAS A WEAK LOW NORTHEAST OF KOTM WITH A FRONT
PASSING NORTH OF THE QUAD CITIES AND EAST INTO NORTHERN INDIANA. A
COLD FRONT RAN FROM THE LOW SOUTHWEST TO THE NE/KS LINE. AN
INVERTED TROF RAN FROM THE LOW INTO SOUTHEAST MINNESOTA WHILE
ANOTHER TROF RAN SOUTHEAST FROM THE LOW INTO CENTRAL ILLINOIS. DEW
POINTS WERE IN THE 60S ACROSS THE MIDWEST WITH POCKETS OF 70
AROUND THE LOW AND COLD FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT SUN SEP 8 2013
THE CONCERNS ARE THE CONVECTION IN THE SOUTHERN CWFA AND THE
APPROACHING LOW CLOUDS FROM WISCONSIN.
THE CONVECTION AROUND KGBG AND NOW IMMEDIATELY WEST OF THERE IS
CONTINUOUSLY FORMING AND MOVING OVER THE SAME AREAS. THE CULPRIT
IS A COMBINATION OF CONVERGENCE AROUND THE TROF OVER THAT AREA.
PER THE RAP TRENDS THIS IS EXPECTED TO CONTINUE FOR THE NEXT
SEVERAL HOURS BEFORE WEAKENING. THUS SOME ISOLATED AREAS WILL SEE
LOCALLY HEAVY RAINFALL THROUGH SUNRISE.
THE RAP IS DOING A RESPECTABLE JOB OF DEPICTING THE LOW CLOUDS
APPROACHING FROM WISCONSIN AND WILL ENTER THE NORTHERN CWFA PRIOR
TO SUNRISE.
FOR TODAY...THE CONVECTION IN THE SOUTHERN CWFA SHOULD DISSIPATE
AFTER SUNRISE WHILE LOW CLOUDS CONTINUE TO OVERSPREAD ACROSS THE
NORTHEAST THIRD TO 40 PERCENT OF THE CWFA. THE FRONT WILL SLOWLY
SAG SOUTH AND IS EXPECTED TO CLEAR THE CWFA DURING THE AFTERNOON.
DIURNAL HEATING IS EXPECTED TO ALLOW VERY ISOLATED SHOWERS AND
THUNDERSTORMS TO DEVELOP DURING THE AFTERNOON IN THE SOUTHERN CWFA
WHERE CONVECTIVE TEMPERATURES SHOULD BE ACHIEVED IN SPITE OF THE
WARM AIR ALOFT.
TONIGHT...MAINLY QUIET AND DRY CONDITIONS ARE EXPECTED AS THE FRONT
BEGINS MOVING BACK NORTH AS A WARM FRONT. ..08..
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN SEP 8 2013
TEMPERATURES WILL BE THE MAIN CONCERN MONDAY AND TUESDAY AS VERY
WARM AIR SURGES NORTHEAST BEHIND A WARM FRONT MOVING THROUGH THE
FORECAST AREA BY EARLY MONDAY AFTERNOON. H8 TEMPS ARE FORECAST TO
INCREASE INTO THE LOW TO MID 20/S IN THE WARM SECTOR BY MONDAY
AFTERNOON. MIXING THESE TEMPERATURES TO THE SURFACE YIELDS MAX
TEMPS IN THE MID TO UPPER 90S WHICH LOOKS REASONABLE FOR THE
SOUTHWEST 2/3RDS. WITH THE WARM FRONT MOVING OUT OF THE NORTHEAST
COUNTIES DURING THE AFTERNOON...HIGHS WERE KEPT IN THE LOW 90S.
DEWPOINTS SHOULD BE IN THE MID OR UPPER 60S MONDAY WHICH WILL BE
HIGH ENOUGH TO PRODUCE HEAT INDEX VALUES AROUND 100 DURING THE
AFTERNOON. BY TUESDAY A COLD FRONT WILL BE JUST NORTHWEST OF THE
AREA AT 12Z AND WILL MOVE SLOWLY SOUTH REACHING THE SOUTHEASTERN
COUNTIES BY LATE AFTERNOON. AREAS ALONG AND SOUTH OF HIGHWAY 30
WILL HAVE PLENTY OF TIME TO HEAT UP AND SHOULD SEE ANOTHER DAY OF
MID 90 TEMPERATURES. TO THE NORTH WITH THE FRONT MOVING THROUGH
EARLY IN THE DAY...HIGHS SHOULD BE AROUND 90. SOUTHWEST WINDS AHEAD
OF THE FRONT ARE PROGGED TO TAP DRIER AIR OVER THE
PLAINS...KEEPING DEWPOINTS LOWER THAN THOSE EXPECTED ON MONDAY.
THE DRIER AIR WILL KEEP HEAT INDEX VALUES UNDER 100. HIGHS IN THE
90S MONDAY AND TUESDAY WILL BE CLOSE TO RECORD HIGHS FOR THE 9TH
AND 10TH OF SEPTEMBER. MONDAYS RECORDS ARE AROUND 100 AND SHOULD
BE JUST OUT OF REACH BUT SLIGHTLY COOLER RECORDS FOR TUESDAY WILL
BE ATTAINABLE ESPECIALLY AT MOLINE AND BURLINGTON. SEE THE CLIMATE
SECTION BELOW FOR MONDAY/S AND TUESDAY/S RECORD HIGHS AND DATE OF
THE LAST OCCURRENCE.
THE RAIN THREAT WILL BE NIL THROUGH EARLY TUESDAY AFTERNOON. THEN
JUST A SLIGHT CHANCE NORTH PRIOR TO 00Z WEDNESDAY. THE WARM SECTOR
SHOULD BE CAPPED...AND AS STATED ABOVE DEWPOINTS WILL BE DRYING
OUT SOME AHEAD OF THE FRONT. THE BEST POTENTIAL FOR RAIN WILL BE
POST FRONTAL WHERE LOW LEVEL MOISTURE WILL BE POOLING AND THE MID
LEVEL CAP STARTS TO ERODE. MODELS WERE ALSO SHOWING SOME DEEP
LAYER FGEN IN THE ENTRANCE REGION OF A H3 80KT JET STREAK OVER MN
AND WI WHICH SHOULD CONTRIBUTE TO THE POST FRONTAL FORCING.
DESPITE THESE SIGNALS FAVORING RAIN...THERE IS STILL A WIDE RANGE
OF QPF FORECASTS AMONG THE MODELS WITH THE LATEST ECM RUN DRY FOR
NEARLY ALL OF THE CWFA. WITH THE MODELS STILL LENDING A LOT OF
UNCERTAINTY TO THE PRECIP FORECAST FOR TUESDAY NIGHT AND WEDNESDAY...
HAVE KEPT THE POPS IN THE CHANCE CATEGORY.
THE FRONT WILL BE SOUTH OF THE AREA BY TUESDAY EVENING ENDING ANY
RAIN THREAT FOR THE REST OF THE WEEK. HIGH PRESSURE SLIDING
SOUTHEAST THROUGH THE GREAT LAKES BY LATE WEEK WILL BRING COOL DRY
AIR TO THE REGION. BY FRIDAY AND SATURDAY WE SHOULD SEE HIGHS IN
THE 70S OVER THE ENTIRE AREA WITH LOWS IN THE 40S AND 50S BY
SATURDAY MORNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1240 PM CDT SUN SEP 8 2013
NEARLY STATIONARY FRONTAL ZONE IS DRAPED OVER FAR SOUTHEAST IOWA AND
WEST CENTRAL ILLINOIS. FAIRLY WIDESPREAD STRATUS WITH MVFR CIGS WAS
NOTED NORTH OF THE FRONT IMPACTING ALL TERMINALS. ANTICIPATE THE
STRATUS AND MVFR CIGS TO LIFT TO VFR AND SCATTERING AT THE TERMINALS
FROM SOUTH TO NORTH THROUGH 00Z. STATIONARY FRONT IS EXPECTED TO
LIFT BACK NORTH AS A WARM FRONT THROUGH THE TERMINALS LATE TONIGHT
AND MONDAY MORNING. ANTICIPATE MORE LOW CLOUDS AND FOG WITH IFR TO
MVFR CONDITIONS DEVELOPING NORTH OF THE WARM FRONT AS SUGGESTED BY
MOST GUIDANCE INCLUDING HRRR...SREF AND RAP MODEL VSBY/CIG PLOTS.
CONDITIONS TO RETURN TO VFR AT ALL SITES BY 18Z MONDAY AS WARM FRONT
LIFTS NORTH OF THE TERMINALS. WINDS WILL BE EASTERLY AT 5-10 KTS
THIS AFTERNOON AND EVENING... WITH OCCASIONAL GUSTS NEAR 20 KTS POSSIBLE
THIS AFTERNOON. LATE TONIGHT AND MONDAY MORNING AS THE WARM FRONT PASSES
WINDS WILL BECOME SOUTHERLY AROUND 10 KTS WITH SOME GUSTS POSSIBLE LATE
MORNING. RAIN CHANCES ARE NOT ZERO DURING THE PERIOD... BUT APPEAR TOO
SMALL FOR INCLUSION IN TERMINALS.
&&
.CLIMATE...
ISSUED AT 113 AM CDT SUN SEP 8 2013
RECORD HIGHS FOR SEPTEMBER 9...
MOLINE.........99 IN 1933
CEDAR RAPIDS...98 IN 1955
DUBUQUE........97 IN 1955
BURLINGTON.....100 IN 1912
RECORD HIGHS FOR SEPTEMBER 10...
MOLINE.........95 IN 1983
CEDAR RAPIDS...98 IN 1931
DUBUQUE........97 IN 1895
BURLINGTON.....97 IN 1933
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...08
SHORT TERM...08
LONG TERM...DLF
AVIATION...05
CLIMATE...DLF
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1158 AM CDT SUN SEP 8 2013
.SHORT TERM.../TODAY /...
ISSUED AT 334 AM CDT SUN SEP 8 2013
THE COLD FRONT HAS PUSHED THROUGH ALL BUT THE FAR SOUTHEAST CORNER
OF IOWA WITH LIGHT NLY WIND OVER THE CWA. WINDS WILL VEER TO NELY
AND EVENTUALLY ELY. LOWERED TEMPS A BIT WITH THE STRONGER PUSH OF
COOLER AIR AND THE PROSPECT FOR MORE CLOUDINESS. AREAS OF CONCERN
ARE THREE FOLD TODAY. FIRST IS THE STRATUS DECK ENTERING NERN IA
THIS MORNING AND HOW FAR IT WILL PUSH TO THE SOUTHWEST. THINKING IS
THAT IT WILL PUSH ABOUT A THIRD OF THE WAY ACROSS THE STATE BEFORE
IT STARTS TO BREAK UP. TEMPS MAY WELL STRUGGLE TO MAKE 80 IN THE
FAR NERN PART OF THE CWA. SECOND CONCERN IS WITH THE MCS OVER THE
DAKOTAS. SPILL OFF CLOUDINESS MAY WELL HAVE A SIGNIFICANT IMPACT ON
TEMPS. THOUGH WE ARE STARTING OUT QUITE WARM...IT WOULD SEEM THAT
FEW PLACES WILL BREAK OUT OF THE 80S...AND THAT WILL BE IN THE FAR
SOUTHWEST. THIRD CONCERN IS THE HRRR DEVELOPMENT OF SHOWER ACTIVITY
OVER WESTERN IA THIS MORNING. DON`T SEE A LOT OF SUPPORT FOR THAT
EVEN GIVEN SOME AC AND VIRGA DEVELOPMENT OVER EASTERN NEBRASKA AT
PRESENT. THERE IS MORE SUPPORT THERE AND IT IS STRUGGLING WITH THE
EML IN PLACE. WITH THAT SAID...WILL GO A TOUGH ABOVE MOS GUIDANCE
FOR HIGHS TODAY. LEFT POPS OUT EXCEPT FOR THE POTENTIAL OF SOME
EARLY MORNING TSRA OVER THE EXTREME SOUTHEAST AS THESE HAVE HAD A
TENDENCY TO BACK DEVELOP THROUGH THE EARLY MORNING HOURS.
.LONG TERM.../TONIGHT THROUGH FRIDAY/...
ISSUED AT 334 AM CDT SUN SEP 8 2013
STRONG WARM ADVECTION WILL PASS THROUGH CENTRAL IOWA LATE TONIGHT
AND THROUGH THE DAY ON MONDAY AS LOW PRESSURE MOVES THROUGH THE
DAKOTAS AND INTO MINNESOTA. A WELL MIXED PROFILE WILL BE IN PLACE
BY THE AFTERNOON FUELED BY BREEZY SOUTHWEST WINDS. DEWPOINTS WILL
DROP INTO THE 50S TO LOWER 60S AS THE PROFILES MIX IN THE
AFTERNOON. HIGH TEMPERATURES WILL JUMP INTO THE MID 90S TO
POSSIBLY LOW 100S BY MID AFTERNOON. THESE READINGS ARE NEAR TO
ABOVE RECORD VALUES. THE CURRENT LATEST 100 DEGREE DAY AT DES
MOINES OCCURRED ON SEPTEMBER 7TH 1939 THEREFORE IF THE FORECAST OF
100 VERIFIES...IT WILL ECLIPSE THAT MARK. BOTH WATERLOO (SEPTEMBER
15TH 1927) AND OTTUMWA (SEPTEMBER 11TH 1936) HAVE HAD 100 DEGREE
DAYS BEYOND THIS POINT.
A FRONTAL BOUNDARY WILL GRADUALLY SAG THROUGH IOWA MONDAY NIGHT
THROUGH TUESDAY NIGHT AS THE AREA OF LOW PRESSURE SHIFTS TO THE
EAST. THE BOUNDARY WILL BE QUITE SLOW TO MOVE SOUTH AS THE UPPER
LEVEL RIDGE STUBBORNLY GIVES WAY TO A SHORT WAVE MOVING EAST ALONG
THE US/CANADIAN BORDER. THE PRIMARY ENERGY WITH THIS SYSTEM WILL
BE PASSING TO THE NORTH OF THE STATE NEAR THE UPPER WAVE AND IN
THE VICINITY OF THE RIGHT REAR QUAD OF THE UPPER JET. THE MAIN
POTENTIAL FOR PRECIPITATION WILL BE POST SFC FRONTAL AND CLOSER TO
THE 850 MB BOUNDARY LATE TUESDAY INTO TUESDAY NIGHT. CONFIDENCE IS
NOT HIGH THAT ANY BENEFICIAL RAIN WILL OCCUR WITH THIS SYSTEM AND
ESPECIALLY IN THE EXPANDING D2 DROUGHT REGION OVER THE CENTRAL AND
WEST CENTRAL AREAS. A TRANSITION TO NORTHWEST FLOW TUESDAY NIGHT
AND WEDNESDAY WILL FINALLY PUSH THE BOUNDARY SOUTH OF THE STATE
AND THIS WILL ALLOW A LARGE CANADIAN HIGH PRESSURE SYSTEM TO DROP
INTO THE UPPER MIDWEST AND WESTERN GREAT LAKES REGION FOR THE END
OF THE WEEK. THE HIGH WILL BRING A REFRESHING BLAST OF COOLER AIR
WITH HIGHS IN THE 70S BY FRIDAY AND OVERNIGHT LOWS POSSIBLE
DROPPING INTO 40S OVER THE NORTH.
&&
.AVIATION...08/18Z
ISSUED AT 1158 AM CDT SUN SEP 8 2013
MVFR CIGS DUE TO STRATUS/STRATOCU WILL TRANSITION TO SCATTERED
CLOUDS THIS AFTN FROM SOUTH TO NORTH...WITH THE KALO AND KMCW
TERMINALS TRANSITIONING THE LATEST. OVERNIGHT...MVFR CIGS ARE
EXPECTED TO RETURN WITH THE BEST CHANCES AT THE NORTHERN TERMINALS.
WARM FROPA OVERNIGHT AND EARLY MON MORNING WILL SHIFT WINDS TO THE
SOUTH AND CLEAR OUT THE CLOUDS FOR MONDAY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MS SEP 13
LONG TERM...DONAVON
AVIATION...ZOGG
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
731 AM CDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 723 AM CDT SUN SEP 8 2013
THE CONVECTION HAS EXITED THE AREA AND A PERIOD OF QUIET WX IS
EXPECTED THROUGH THE EARLY AFTERNOON. PER THE RAP/WRF TRENDS THE
LOW CLOUDS COMING OFF LAKE MICHIGAN ARE MOVING JUST A BIT FASTER
THAN EXPECTED. HOWEVER...WITH THE SUN NOW UP THE SOUTHWARD
EXPANSION OF THE CLOUDS SHOULD BE HALTED. CLOUD COVER WILL MAKE
TEMPERATURES INTERESTING TODAY. THOSE AREAS THAT HAVE CLOUDS
SHOULD REMAIN IN THE UPPER 60S TO LOWER 70S FOR A GOOD PORTION OF
THE MORNING BEFORE RISING.
CONVECTION THIS AFTERNOON IS QUESTIONABLE. THERE IS A WARM LAYER
ALOFT THAT MAY PREVENT ANY CONVECTION FROM OCCURRING. IF
CONVECTION DOES OCCUR THE MOST LIKELY AREA WILL BE SOUTH OF I-80
WHERE THE STRONGER DIFFERENTIAL HEATING WILL OCCUR.
&&
.SYNOPSIS...
ISSUED AT 315 AM CDT SUN SEP 8 2013
06Z SFC ANALYSIS HAS A WEAK LOW NORTHEAST OF KOTM WITH A FRONT
PASSING NORTH OF THE QUAD CITIES AND EAST INTO NORTHERN INDIANA. A
COLD FRONT RAN FROM THE LOW SOUTHWEST TO THE NE/KS LINE. AN
INVERTED TROF RAN FROM THE LOW INTO SOUTHEAST MINNESOTA WHILE
ANOTHER TROF RAN SOUTHEAST FROM THE LOW INTO CENTRAL ILLINOIS. DEW
POINTS WERE IN THE 60S ACROSS THE MIDWEST WITH POCKETS OF 70
AROUND THE LOW AND COLD FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT SUN SEP 8 2013
THE CONCERNS ARE THE CONVECTION IN THE SOUTHERN CWFA AND THE
APPROACHING LOW CLOUDS FROM WISCONSIN.
THE CONVECTION AROUND KGBG AND NOW IMMEDIATELY WEST OF THERE IS
CONTINUOUSLY FORMING AND MOVING OVER THE SAME AREAS. THE CULPRIT
IS A COMBINATION OF CONVERGENCE AROUND THE TROF OVER THAT AREA.
PER THE RAP TRENDS THIS IS EXPECTED TO CONTINUE FOR THE NEXT
SEVERAL HOURS BEFORE WEAKENING. THUS SOME ISOLATED AREAS WILL SEE
LOCALLY HEAVY RAINFALL THROUGH SUNRISE.
THE RAP IS DOING A RESPECTABLE JOB OF DEPICTING THE LOW CLOUDS
APPROACHING FROM WISCONSIN AND WILL ENTER THE NORTHERN CWFA PRIOR
TO SUNRISE.
FOR TODAY...THE CONVECTION IN THE SOUTHERN CWFA SHOULD DISSIPATE
AFTER SUNRISE WHILE LOW CLOUDS CONTINUE TO OVERSPREAD ACROSS THE
NORTHEAST THIRD TO 40 PERCENT OF THE CWFA. THE FRONT WILL SLOWLY
SAG SOUTH AND IS EXPECTED TO CLEAR THE CWFA DURING THE AFTERNOON.
DIURNAL HEATING IS EXPECTED TO ALLOW VERY ISOLATED SHOWERS AND
THUNDERSTORMS TO DEVELOP DURING THE AFTERNOON IN THE SOUTHERN CWFA
WHERE CONVECTIVE TEMPERATURES SHOULD BE ACHIEVED IN SPITE OF THE
WARM AIR ALOFT.
TONIGHT...MAINLY QUIET AND DRY CONDITIONS ARE EXPECTED AS THE FRONT
BEGINS MOVING BACK NORTH AS A WARM FRONT. ..08..
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN SEP 8 2013
TEMPERATURES WILL BE THE MAIN CONCERN MONDAY AND TUESDAY AS VERY
WARM AIR SURGES NORTHEAST BEHIND A WARM FRONT MOVING THROUGH THE
FORECAST AREA BY EARLY MONDAY AFTERNOON. H8 TEMPS ARE FORECAST TO
INCREASE INTO THE LOW TO MID 20/S IN THE WARM SECTOR BY MONDAY
AFTERNOON. MIXING THESE TEMPERATURES TO THE SURFACE YIELDS MAX
TEMPS IN THE MID TO UPPER 90S WHICH LOOKS REASONABLE FOR THE
SOUTHWEST 2/3RDS. WITH THE WARM FRONT MOVING OUT OF THE NORTHEAST
COUNTIES DURING THE AFTERNOON...HIGHS WERE KEPT IN THE LOW 90S.
DEWPOINTS SHOULD BE IN THE MID OR UPPER 60S MONDAY WHICH WILL BE
HIGH ENOUGH TO PRODUCE HEAT INDEX VALUES AROUND 100 DURING THE
AFTERNOON. BY TUESDAY A COLD FRONT WILL BE JUST NORTHWEST OF THE
AREA AT 12Z AND WILL MOVE SLOWLY SOUTH REACHING THE SOUTHEASTERN
COUNTIES BY LATE AFTERNOON. AREAS ALONG AND SOUTH OF HIGHWAY 30
WILL HAVE PLENTY OF TIME TO HEAT UP AND SHOULD SEE ANOTHER DAY OF
MID 90 TEMPERATURES. TO THE NORTH WITH THE FRONT MOVING THROUGH
EARLY IN THE DAY...HIGHS SHOULD BE AROUND 90. SOUTHWEST WINDS AHEAD
OF THE FRONT ARE PROGGED TO TAP DRIER AIR OVER THE
PLAINS...KEEPING DEWPOINTS LOWER THAN THOSE EXPECTED ON MONDAY.
THE DRIER AIR WILL KEEP HEAT INDEX VALUES UNDER 100. HIGHS IN THE
90S MONDAY AND TUESDAY WILL BE CLOSE TO RECORD HIGHS FOR THE 9TH
AND 10TH OF SEPTEMBER. MONDAYS RECORDS ARE AROUND 100 AND SHOULD
BE JUST OUT OF REACH BUT SLIGHTLY COOLER RECORDS FOR TUESDAY WILL
BE ATTAINABLE ESPECIALLY AT MOLINE AND BURLINGTON. SEE THE CLIMATE
SECTION BELOW FOR MONDAY/S AND TUESDAY/S RECORD HIGHS AND DATE OF
THE LAST OCCURRENCE.
THE RAIN THREAT WILL BE NIL THROUGH EARLY TUESDAY AFTERNOON. THEN
JUST A SLIGHT CHANCE NORTH PRIOR TO 00Z WEDNESDAY. THE WARM SECTOR
SHOULD BE CAPPED...AND AS STATED ABOVE DEWPOINTS WILL BE DRYING
OUT SOME AHEAD OF THE FRONT. THE BEST POTENTIAL FOR RAIN WILL BE
POST FRONTAL WHERE LOW LEVEL MOISTURE WILL BE POOLING AND THE MID
LEVEL CAP STARTS TO ERODE. MODELS WERE ALSO SHOWING SOME DEEP
LAYER FGEN IN THE ENTRANCE REGION OF A H3 80KT JET STREAK OVER MN
AND WI WHICH SHOULD CONTRIBUTE TO THE POST FRONTAL FORCING.
DESPITE THESE SIGNALS FAVORING RAIN...THERE IS STILL A WIDE RANGE
OF QPF FORECASTS AMONG THE MODELS WITH THE LATEST ECM RUN DRY FOR
NEARLY ALL OF THE CWFA. WITH THE MODELS STILL LENDING A LOT OF
UNCERTAINTY TO THE PRECIP FORECAST FOR TUESDAY NIGHT AND WEDNESDAY...
HAVE KEPT THE POPS IN THE CHANCE CATEGORY.
THE FRONT WILL BE SOUTH OF THE AREA BY TUESDAY EVENING ENDING ANY
RAIN THREAT FOR THE REST OF THE WEEK. HIGH PRESSURE SLIDING
SOUTHEAST THROUGH THE GREAT LAKES BY LATE WEEK WILL BRING COOL DRY
AIR TO THE REGION. BY FRIDAY AND SATURDAY WE SHOULD SEE HIGHS IN
THE 70S OVER THE ENTIRE AREA WITH LOWS IN THE 40S AND 50S BY
SATURDAY MORNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 723 AM CDT SUN SEP 8 2013
LOW CLOUDS COMING OFF LAKE MICHIGAN WILL CREATE MVFR/IFR
CONDITIONS AT KCID/KMLI/KDBQ. KBRL IS EXPECTED TO REMAIN VFR. THE
MVFR/IFR CONDITIONS WILL SLOWLY IMPROVE TO VFR BY 00Z/09. ISOLATED
SHRA AND POSSIBLY A TSRA MAY DEVELOP AFT 18Z/08 BUT THE
PROBABILITY IS QUITE LOW THAT A TAF SITE WILL BE AFFECTED.
&&
.CLIMATE...
ISSUED AT 113 AM CDT SUN SEP 8 2013
RECORD HIGHS FOR SEPTEMBER 9...
MOLINE.........99 IN 1933
CEDAR RAPIDS...98 IN 1955
DUBUQUE........97 IN 1955
BURLINGTON.....100 IN 1912
RECORD HIGHS FOR SEPTEMBER 10...
MOLINE.........95 IN 1983
CEDAR RAPIDS...98 IN 1931
DUBUQUE........97 IN 1895
BURLINGTON.....97 IN 1933
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...08
SHORT TERM...08
LONG TERM...DLF
AVIATION...08
CLIMATE...DLF
AREA FORECAST DISCUSSION
NWS DES MOINES IA
638 AM CDT SUN SEP 8 2013
.SHORT TERM.../TODAY /...
ISSUED AT 334 AM CDT SUN SEP 8 2013
THE COLD FRONT HAS PUSHED THROUGH ALL BUT THE FAR SOUTHEAST CORNER
OF IOWA WITH LIGHT NLY WIND OVER THE CWA. WINDS WILL VEER TO NELY
AND EVENTUALLY ELY. LOWERED TEMPS A BIT WITH THE STRONGER PUSH OF
COOLER AIR AND THE PROSPECT FOR MORE CLOUDINESS. AREAS OF CONCERN
ARE THREE FOLD TODAY. FIRST IS THE STRATUS DECK ENTERING NERN IA
THIS MORNING AND HOW FAR IT WILL PUSH TO THE SOUTHWEST. THINKING IS
THAT IT WILL PUSH ABOUT A THIRD OF THE WAY ACROSS THE STATE BEFORE
IT STARTS TO BREAK UP. TEMPS MAY WELL STRUGGLE TO MAKE 80 IN THE
FAR NERN PART OF THE CWA. SECOND CONCERN IS WITH THE MCS OVER THE
DAKOTAS. SPILL OFF CLOUDINESS MAY WELL HAVE A SIGNIFICANT IMPACT ON
TEMPS. THOUGH WE ARE STARTING OUT QUITE WARM...IT WOULD SEEM THAT
FEW PLACES WILL BREAK OUT OF THE 80S...AND THAT WILL BE IN THE FAR
SOUTHWEST. THIRD CONCERN IS THE HRRR DEVELOPMENT OF SHOWER ACTIVITY
OVER WESTERN IA THIS MORNING. DON`T SEE A LOT OF SUPPORT FOR THAT
EVEN GIVEN SOME AC AND VIRGA DEVELOPMENT OVER EASTERN NEBRASKA AT
PRESENT. THERE IS MORE SUPPORT THERE AND IT IS STRUGGLING WITH THE
EML IN PLACE. WITH THAT SAID...WILL GO A TOUGH ABOVE MOS GUIDANCE
FOR HIGHS TODAY. LEFT POPS OUT EXCEPT FOR THE POTENTIAL OF SOME
EARLY MORNING TSRA OVER THE EXTREME SOUTHEAST AS THESE HAVE HAD A
TENDENCY TO BACK DEVELOP THROUGH THE EARLY MORNING HOURS.
.LONG TERM.../TONIGHT THROUGH FRIDAY/...
ISSUED AT 334 AM CDT SUN SEP 8 2013
STRONG WARM ADVECTION WILL PASS THROUGH CENTRAL IOWA LATE TONIGHT
AND THROUGH THE DAY ON MONDAY AS LOW PRESSURE MOVES THROUGH THE
DAKOTAS AND INTO MINNESOTA. A WELL MIXED PROFILE WILL BE IN PLACE
BY THE AFTERNOON FUELED BY BREEZY SOUTHWEST WINDS. DEWPOINTS WILL
DROP INTO THE 50S TO LOWER 60S AS THE PROFILES MIX IN THE
AFTERNOON. HIGH TEMPERATURES WILL JUMP INTO THE MID 90S TO
POSSIBLY LOW 100S BY MID AFTERNOON. THESE READINGS ARE NEAR TO
ABOVE RECORD VALUES. THE CURRENT LATEST 100 DEGREE DAY AT DES
MOINES OCCURRED ON SEPTEMBER 7TH 1939 THEREFORE IF THE FORECAST OF
100 VERIFIES...IT WILL ECLIPSE THAT MARK. BOTH WATERLOO (SEPTEMBER
15TH 1927) AND OTTUMWA (SEPTEMBER 11TH 1936) HAVE HAD 100 DEGREE
DAYS BEYOND THIS POINT.
A FRONTAL BOUNDARY WILL GRADUALLY SAG THROUGH IOWA MONDAY NIGHT
THROUGH TUESDAY NIGHT AS THE AREA OF LOW PRESSURE SHIFTS TO THE
EAST. THE BOUNDARY WILL BE QUITE SLOW TO MOVE SOUTH AS THE UPPER
LEVEL RIDGE STUBBORNLY GIVES WAY TO A SHORT WAVE MOVING EAST ALONG
THE US/CANADIAN BORDER. THE PRIMARY ENERGY WITH THIS SYSTEM WILL
BE PASSING TO THE NORTH OF THE STATE NEAR THE UPPER WAVE AND IN
THE VICINITY OF THE RIGHT REAR QUAD OF THE UPPER JET. THE MAIN
POTENTIAL FOR PRECIPITATION WILL BE POST SFC FRONTAL AND CLOSER TO
THE 850 MB BOUNDARY LATE TUESDAY INTO TUESDAY NIGHT. CONFIDENCE IS
NOT HIGH THAT ANY BENEFICIAL RAIN WILL OCCUR WITH THIS SYSTEM AND
ESPECIALLY IN THE EXPANDING D2 DROUGHT REGION OVER THE CENTRAL AND
WEST CENTRAL AREAS. A TRANSITION TO NORTHWEST FLOW TUESDAY NIGHT
AND WEDNESDAY WILL FINALLY PUSH THE BOUNDARY SOUTH OF THE STATE
AND THIS WILL ALLOW A LARGE CANADIAN HIGH PRESSURE SYSTEM TO DROP
INTO THE UPPER MIDWEST AND WESTERN GREAT LAKES REGION FOR THE END
OF THE WEEK. THE HIGH WILL BRING A REFRESHING BLAST OF COOLER AIR
WITH HIGHS IN THE 70S BY FRIDAY AND OVERNIGHT LOWS POSSIBLE
DROPPING INTO 40S OVER THE NORTH.
&&
.AVIATION...08/12Z
ISSUED AT 635 AM CDT SUN SEP 8 2013
COLD FRONT ALONG THE IA/MO BORDER WILL MOVE LITTLE TODAY...THEN
BEGIN TO LIFT NORTH AS A WARM FRONT LATE TONIGHT INTO MON.
MULTIPLE CLOUDS LAYERS OVER THE STATE TODAY...BUT ONLY ONE OF AVN
SIGNIFICANCE IS TH STRATUS DECK ENTERING IA FROM THE NORTHEAST.
FEEL THE STRATUS WILL REMAIN NORTH OF KOTM, MAY JUST BRUSH
KDSM...AND BE A CIG EVENT THROUGH THE MORNING INTO THE EARLY
AFTERNOON AT THE OTHER THREE SITES. STRATUS MAY REFORM OVER THE
NERN TAF SITES LATE TONIGHT TO THE NORTH OF THE WARM FRONT. MVFR
FOG IS EXPECTED ACROSS THE STATE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MS SEP 13
LONG TERM...DONAVON
AVIATION...MS SEP 13
AREA FORECAST DISCUSSION
NWS DES MOINES IA
335 AM CDT SUN SEP 8 2013
.SHORT TERM.../TODAY /...
ISSUED AT 334 AM CDT SUN SEP 8 2013
THE COLD FRONT HAS PUSHED THROUGH ALL BUT THE FAR SOUTHEAST CORNER
OF IOWA WITH LIGHT NLY WIND OVER THE CWA. WINDS WILL VEER TO NELY
AND EVENTUALLY ELY. LOWERED TEMPS A BIT WITH THE STRONGER PUSH OF
COOLER AIR AND THE PROSPECT FOR MORE CLOUDINESS. AREAS OF CONCERN
ARE THREE FOLD TODAY. FIRST IS THE STRATUS DECK ENTERING NERN IA
THIS MORNING AND HOW FAR IT WILL PUSH TO THE SOUTHWEST. THINKING IS
THAT IT WILL PUSH ABOUT A THIRD OF THE WAY ACROSS THE STATE BEFORE
IT STARTS TO BREAK UP. TEMPS MAY WELL STRUGGLE TO MAKE 80 IN THE
FAR NERN PART OF THE CWA. SECOND CONCERN IS WITH THE MCS OVER THE
DAKOTAS. SPILL OFF CLOUDINESS MAY WELL HAVE A SIGNIFICANT IMPACT ON
TEMPS. THOUGH WE ARE STARTING OUT QUITE WARM...IT WOULD SEEM THAT
FEW PLACES WILL BREAK OUT OF THE 80S...AND THAT WILL BE IN THE FAR
SOUTHWEST. THIRD CONCERN IS THE HRRR DEVELOPMENT OF SHOWER ACTIVITY
OVER WESTERN IA THIS MORNING. DON`T SEE A LOT OF SUPPORT FOR THAT
EVEN GIVEN SOME AC AND VIRGA DEVELOPMENT OVER EASTERN NEBRASKA AT
PRESENT. THERE IS MORE SUPPORT THERE AND IT IS STRUGGLING WITH THE
EML IN PLACE. WITH THAT SAID...WILL GO A TOUGH ABOVE MOS GUIDANCE
FOR HIGHS TODAY. LEFT POPS OUT EXCEPT FOR THE POTENTIAL OF SOME
EARLY MORNING TSRA OVER THE EXTREME SOUTHEAST AS THESE HAVE HAD A
TENDENCY TO BACK DEVELOP THROUGH THE EARLY MORNING HOURS.
.LONG TERM.../TONIGHT THROUGH FRIDAY/...
ISSUED AT 334 AM CDT SUN SEP 8 2013
STRONG WARM ADVECTION WILL PASS THROUGH CENTRAL IOWA LATE TONIGHT
AND THROUGH THE DAY ON MONDAY AS LOW PRESSURE MOVES THROUGH THE
DAKOTAS AND INTO MINNESOTA. A WELL MIXED PROFILE WILL BE IN PLACE
BY THE AFTERNOON FUELED BY BREEZY SOUTHWEST WINDS. DEWPOINTS WILL
DROP INTO THE 50S TO LOWER 60S AS THE PROFILES MIX IN THE
AFTERNOON. HIGH TEMPERATURES WILL JUMP INTO THE MID 90S TO
POSSIBLY LOW 100S BY MID AFTERNOON. THESE READINGS ARE NEAR TO
ABOVE RECORD VALUES. THE CURRENT LATEST 100 DEGREE DAY AT DES
MOINES OCCURRED ON SEPTEMBER 7TH 1939 THEREFORE IF THE FORECAST OF
100 VERIFIES...IT WILL ECLIPSE THAT MARK. BOTH WATERLOO (SEPTEMBER
15TH 1927) AND OTTUMWA (SEPTEMBER 11TH 1936) HAVE HAD 100 DEGREE
DAYS BEYOND THIS POINT.
A FRONTAL BOUNDARY WILL GRADUALLY SAG THROUGH IOWA MONDAY NIGHT
THROUGH TUESDAY NIGHT AS THE AREA OF LOW PRESSURE SHIFTS TO THE
EAST. THE BOUNDARY WILL BE QUITE SLOW TO MOVE SOUTH AS THE UPPER
LEVEL RIDGE STUBBORNLY GIVES WAY TO A SHORT WAVE MOVING EAST ALONG
THE US/CANADIAN BORDER. THE PRIMARY ENERGY WITH THIS SYSTEM WILL
BE PASSING TO THE NORTH OF THE STATE NEAR THE UPPER WAVE AND IN
THE VICINITY OF THE RIGHT REAR QUAD OF THE UPPER JET. THE MAIN
POTENTIAL FOR PRECIPITATION WILL BE POST SFC FRONTAL AND CLOSER TO
THE 850 MB BOUNDARY LATE TUESDAY INTO TUESDAY NIGHT. CONFIDENCE IS
NOT HIGH THAT ANY BENEFICIAL RAIN WILL OCCUR WITH THIS SYSTEM AND
ESPECIALLY IN THE EXPANDING D2 DROUGHT REGION OVER THE CENTRAL AND
WEST CENTRAL AREAS. A TRANSITION TO NORTHWEST FLOW TUESDAY NIGHT
AND WEDNESDAY WILL FINALLY PUSH THE BOUNDARY SOUTH OF THE STATE
AND THIS WILL ALLOW A LARGE CANADIAN HIGH PRESSURE SYSTEM TO DROP
INTO THE UPPER MIDWEST AND WESTERN GREAT LAKES REGION FOR THE END
OF THE WEEK. THE HIGH WILL BRING A REFRESHING BLAST OF COOLER AIR
WITH HIGHS IN THE 70S BY FRIDAY AND OVERNIGHT LOWS POSSIBLE
DROPPING INTO 40S OVER THE NORTH.
&&
.AVIATION...08/06Z
ISSUED AT 1152 PM CDT SAT SEP 7 2013
WINDS WILL SHIFT FROM THE NORTH TO THE EAST BEHIND BOUNDARY. WITH
LIGHTER WINDS ACROSS THE NORTH AND CLEAR SKIES THROUGH MUCH OF THE
OVERNIGHT ANTICIPATE AREAS OF BR TO AFFECT NORTHERN TAF SITES
KFOD/KMCW/KALO/KDSM NEAR 12Z...WITH IFR CONDITIONS POSSIBLE. BR
WILL QUICKLY LIFT AS WINDS INCREASE AFTER 12Z. MAY SEE GUSTS IN
THE AFTERNOON. WINDS WILL BECOME MORE SOUTHERLY LATE IN THE PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MS SEP 2013
LONG TERM...DONAVON
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
323 AM CDT SUN SEP 8 2013
.SYNOPSIS...
ISSUED AT 315 AM CDT SUN SEP 8 2013
06Z SFC ANALYSIS HAS A WEAK LOW NORTHEAST OF KOTM WITH A FRONT
PASSING NORTH OF THE QUAD CITIES AND EAST INTO NORTHERN INDIANA. A
COLD FRONT RAN FROM THE LOW SOUTHWEST TO THE NE/KS LINE. AN
INVERTED TROF RAN FROM THE LOW INTO SOUTHEAST MINNESOTA WHILE
ANOTHER TROF RAN SOUTHEAST FROM THE LOW INTO CENTRAL ILLINOIS. DEW
POINTS WERE IN THE 60S ACROSS THE MIDWEST WITH POCKETS OF 70
AROUND THE LOW AND COLD FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT SUN SEP 8 2013
THE CONCERNS ARE THE CONVECTION IN THE SOUTHERN CWFA AND THE
APPROACHING LOW CLOUDS FROM WISCONSIN.
THE CONVECTION AROUND KGBG AND NOW IMMEDIATELY WEST OF THERE IS
CONTINUOUSLY FORMING AND MOVING OVER THE SAME AREAS. THE CULPRIT
IS A COMBINATION OF CONVERGENCE AROUND THE TROF OVER THAT AREA.
PER THE RAP TRENDS THIS IS EXPECTED TO CONTINUE FOR THE NEXT
SEVERAL HOURS BEFORE WEAKENING. THUS SOME ISOLATED AREAS WILL SEE
LOCALLY HEAVY RAINFALL THROUGH SUNRISE.
THE RAP IS DOING A RESPECTABLE JOB OF DEPICTING THE LOW CLOUDS
APPROACHING FROM WISCONSIN AND WILL ENTER THE NORTHERN CWFA PRIOR
TO SUNRISE.
FOR TODAY...THE CONVECTION IN THE SOUTHERN CWFA SHOULD DISSIPATE
AFTER SUNRISE WHILE LOW CLOUDS CONTINUE TO OVERSPREAD ACROSS THE
NORTHEAST THIRD TO 40 PERCENT OF THE CWFA. THE FRONT WILL SLOWLY
SAG SOUTH AND IS EXPECTED TO CLEAR THE CWFA DURING THE AFTERNOON.
DIURNAL HEATING IS EXPECTED TO ALLOW VERY ISOLATED SHOWERS AND
THUNDERSTORMS TO DEVELOP DURING THE AFTERNOON IN THE SOUTHERN CWFA
WHERE CONVECTIVE TEMPERATURES SHOULD BE ACHIEVED IN SPITE OF THE
WARM AIR ALOFT.
TONIGHT...MAINLY QUIET AND DRY CONDITIONS ARE EXPECTED AS THE FRONT
BEGINS MOVING BACK NORTH AS A WARM FRONT. ..08..
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN SEP 8 2013
TEMPERATURES WILL BE THE MAIN CONCERN MONDAY AND TUESDAY AS VERY
WARM AIR SURGES NORTHEAST BEHIND A WARM FRONT MOVING THROUGH THE
FORECAST AREA BY EARLY MONDAY AFTERNOON. H8 TEMPS ARE FORECAST TO
INCREASE INTO THE LOW TO MID 20/S IN THE WARM SECTOR BY MONDAY
AFTERNOON. MIXING THESE TEMPERATURES TO THE SURFACE YIELDS MAX
TEMPS IN THE MID TO UPPER 90S WHICH LOOKS REASONABLE FOR THE
SOUTHWEST 2/3RDS. WITH THE WARM FRONT MOVING OUT OF THE NORTHEAST
COUNTIES DURING THE AFTERNOON...HIGHS WERE KEPT IN THE LOW 90S.
DEWPOINTS SHOULD BE IN THE MID OR UPPER 60S MONDAY WHICH WILL BE
HIGH ENOUGH TO PRODUCE HEAT INDEX VALUES AROUND 100 DURING THE
AFTERNOON. BY TUESDAY A COLD FRONT WILL BE JUST NORTHWEST OF THE
AREA AT 12Z AND WILL MOVE SLOWLY SOUTH REACHING THE SOUTHEASTERN
COUNTIES BY LATE AFTERNOON. AREAS ALONG AND SOUTH OF HIGHWAY 30
WILL HAVE PLENTY OF TIME TO HEAT UP AND SHOULD SEE ANOTHER DAY OF
MID 90 TEMPERATURES. TO THE NORTH WITH THE FRONT MOVING THROUGH
EARLY IN THE DAY...HIGHS SHOULD BE AROUND 90. SOUTHWEST WINDS AHEAD
OF THE FRONT ARE PROGGED TO TAP DRIER AIR OVER THE
PLAINS...KEEPING DEWPOINTS LOWER THAN THOSE EXPECTED ON MONDAY.
THE DRIER AIR WILL KEEP HEAT INDEX VALUES UNDER 100. HIGHS IN THE
90S MONDAY AND TUESDAY WILL BE CLOSE TO RECORD HIGHS FOR THE 9TH
AND 10TH OF SEPTEMBER. MONDAYS RECORDS ARE AROUND 100 AND SHOULD
BE JUST OUT OF REACH BUT SLIGHTLY COOLER RECORDS FOR TUESDAY WILL
BE ATTAINABLE ESPECIALLY AT MOLINE AND BURLINGTON. SEE THE CLIMATE
SECTION BELOW FOR MONDAY/S AND TUESDAY/S RECORD HIGHS AND DATE OF
THE LAST OCCURRENCE.
THE RAIN THREAT WILL BE NIL THROUGH EARLY TUESDAY AFTERNOON. THEN
JUST A SLIGHT CHANCE NORTH PRIOR TO 00Z WEDNESDAY. THE WARM SECTOR
SHOULD BE CAPPED...AND AS STATED ABOVE DEWPOINTS WILL BE DRYING
OUT SOME AHEAD OF THE FRONT. THE BEST POTENTIAL FOR RAIN WILL BE
POST FRONTAL WHERE LOW LEVEL MOISTURE WILL BE POOLING AND THE MID
LEVEL CAP STARTS TO ERODE. MODELS WERE ALSO SHOWING SOME DEEP
LAYER FGEN IN THE ENTRANCE REGION OF A H3 80KT JET STREAK OVER MN
AND WI WHICH SHOULD CONTRIBUTE TO THE POST FRONTAL FORCING.
DESPITE THESE SIGNALS FAVORING RAIN...THERE IS STILL A WIDE RANGE
OF QPF FORECASTS AMONG THE MODELS WITH THE LATEST ECM RUN DRY FOR
NEARLY ALL OF THE CWFA. WITH THE MODELS STILL LENDING A LOT OF
UNCERTAINTY TO THE PRECIP FORECAST FOR TUESDAY NIGHT AND WEDNESDAY...
HAVE KEPT THE POPS IN THE CHANCE CATEGORY.
THE FRONT WILL BE SOUTH OF THE AREA BY TUESDAY EVENING ENDING ANY
RAIN THREAT FOR THE REST OF THE WEEK. HIGH PRESSURE SLIDING
SOUTHEAST THROUGH THE GREAT LAKES BY LATE WEEK WILL BRING COOL DRY
AIR TO THE REGION. BY FRIDAY AND SATURDAY WE SHOULD SEE HIGHS IN
THE 70S OVER THE ENTIRE AREA WITH LOWS IN THE 40S AND 50S BY
SATURDAY MORNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1124 PM CDT SUN SEP 8 2013
A DRY COLD FRONTAL PASSAGE IS OCCURRING OVER EASTERN IOWA AS OF 04Z
TONIGHT...AND ONLY A FEW ISOLATED SHOWERS ARE NOW EXPECTED IN FAR
SOUTHEAST IOWA AND WEST CENTRAL ILLINOIS THROUGH 09Z/08.
OTHERWISE...ATTENTION IS TURNING TOWARD A HIGH LIKELIHOOD OF
STRATUS AND POSSIBLE MVFR FOG TOWARD MORNING. SURFACE WINDS AND
WINDS ALOFT WILL BECOME EASTERLY...PULLING IN COOLER AIR OFF LAKE
MICHIGAN. THIS SHOULD CREATE A WIDESPREAD STRATUS FIELD OVER ALL
OF EASTERN IOWA AND NORTHERN ILLINOIS. THIS STRATUS SHOULD HAVE
CIGS OF 800 FT TO 2000 FT...AND MAY LINGER THROUGH AT LEAST 18Z/08
BEFORE LIFTING AND SCATTERING OUT. ERVIN
&&
.CLIMATE...
ISSUED AT 113 AM CDT SUN SEP 8 2013
RECORD HIGHS FOR SEPTEMBER 9...
MOLINE.........99 IN 1933
CEDAR RAPIDS...98 IN 1955
DUBUQUE........97 IN 1955
BURLINGTON.....100 IN 1912
RECORD HIGHS FOR SEPTEMBER 10...
MOLINE.........95 IN 1983
CEDAR RAPIDS...98 IN 1931
DUBUQUE........97 IN 1895
BURLINGTON.....97 IN 1933
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...DLF
AVIATION...ERVIN
CLIMATE...DLF
AREA FORECAST DISCUSSION
NWS GOODLAND KS
516 PM MDT MON SEP 9 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 237 PM MDT MON SEP 9 2013
AS OF 3 PM CDT...2 PM MDT...SKIES ACROSS THE TRI-STATE AREA WERE
MOSTLY CLEAR WITH THE EXCEPTION OF SOME PATCHES OF DAYTIME CUMULUS.
TEMPERATURES HAVE RISEN INTO THE LOW 90S TO NEAR 100 IN A FEW SPOTS
ACROSS RED WILLOW...DECATUR...NORTON AND GRAHAM COUNTIES. WINDS WERE
GENERALLY FROM THE SOUTH AT 10 TO 20 MPH WITH GUSTS 25 TO 30 MPH.
DEWPOINTS WERE ON A SLOW DECLINE THIS AFTERNOON. A COLD FRONT WAS
LOCATED ACROSS NORTHEAST COLORADO AND SOUTHWEST NEBRASKA. AN AREA OF
LOW PRESSURE WAS DRAPED ACROSS THE AREA...STRETCHING FROM SOUTHWEST
NEBRASKA TO THE COLORADO FRONT RANGE. FIRE WEATHER HAS BECOME A
CONCERN THIS AFTERNOON AND WILL BE ADDRESSED IN A FIRE WEATHER
SECTION BELOW.
FOR THIS AFTERNOON AND TONIGHT...SURFACE CONVERGENCE IS PROJECTED TO
INCREASE ALONG THE COLD FRONT...ALLOWING SOME ISOLATED TO WIDELY
SCATTERED THUNDERSTORMS TO DEVELOP. IN ADDITION...CONVECTION
DEVELOPING OVER THE ROCKIES MAY ORGANIZE AND MOVE EAST INTO THE
REGION FROM THE LATEST RUNS OF THE HRRR MODEL. MOST OTHER MODELS
HOLD ALL PRECIPITATION OFF AND KEEP IT TO THE NORTHWEST OF THE
FORECAST AREA. A STRONG STORM OR TWO IS POSSIBLE WITH DAMAGING
WINDS AND SMALL HAIL AS THE MAIN THREAT. HOWEVER...INSTABILITY IS
NOT AS HIGH AS NEEDED FOR A MORE WIDESPREAD THREAT OF SEVERE
WEATHER. THE FRONT SHOULD MOVE TO THE SOUTH DURING THE OVERNIGHT
HOURS...BRINGING COOLER TEMPERATURES...MORE MOISTURE TO THE AIR
AND A WIND SHIFT. LOW TEMPERATURES WILL VARY ACROSS THE REGION
WITH LOW 60S ACROSS EAST COLORADO AND MID 60S TO NEAR 70 FOR THE
REST OF THE AREA.
FOR TOMORROW...THE COLD FRONT IS EXPECTED TO STALL ACROSS THE AREA.
IN ADDITION TO THE FRONT...AN UPPER LEVEL DISTURBANCE WILL APPROACH
FROM THE WEST...PROVIDING EXTRA LIFT FOR SHOWER AND THUNDERSTORM
DEVELOPMENT. CHANCES FOR PRECIPITATION WILL BE MUCH HIGHER DURING
THE LATE AFTERNOON TO EVENING HOURS FOR A LARGER AREA. TEMPERATURES
BEHIND THE FRONT WILL BE NOTICEABLY COOLER WITH HIGHS IN THE UPPER
70S TO LOW 80S. ALONG AND AHEAD OF THE FRONT...TEMPERATURES WILL BE
WARM WITH HIGHS IN THE MID 80S TO LOW 90S WHERE DAYTIME HEATING
LASTS LONGER BEFORE CLOUDS AND CONVECTIVE ACTIVITY DEVELOPS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 1249 PM MDT MON SEP 9 2013
PATTERN CHANGE WILL OCCUR DURING THIS PERIOD AS THE UPPER RIDGE
WHICH HAS BEEN DOMINANT WILL SHIFT TO THE SOUTHEASTERN CONUS AND
TROUGH WHICH HAS BEEN OVER THE WEST WILL MOVE TO THE CENTRAL AND
NORTHERN ROCKIES. THIS WILL BRING NEAR TO BELOW NORMAL
TEMPERATURES AND OCCASIONAL CHANCES FOR PRECIPITATION TO THE AREA.
FIRST CHANCE FOR RAIN WILL OCCUR TUESDAY NIGHT WITH SHORTWAVE
TROUGH MOVING UP IN THE SOUTHWEST FLOW ALOFT. ANOTHER SHORTWAVE IS
FORECAST ON THURSDAY. BOTH SYSTEMS WILL HAVE PLENTIFUL MOISTURE TO
WORK WITH A TROPICAL CONNECTION TO THE BAJA. RAIN CHANCES CONTINUE
THROUGH THE WEEKEND AS THE UPPER LOW OPENS UP AND EVENTUALLY GETS
ENTRAINED IN THE NORTHERN STREAM. LATE IN THE PERIOD AN UPPER RIDGE
WILL BEGIN TO REBUILD BEHIND THE DEPARTING SYSTEM SIGNALING THE
RETURN OF WARM AND DRY CONDITIONS EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 515 PM MDT MON SEP 9 2013
VFR CONDITIONS SHOULD PREVAIL THROUGH THE TAF PERIOD AT KGLD AND
KMCK. WITH TD VALUES INCREASING I DONT WANT TO COMPLETELY RULE OUT
IFR/MVFR CONDITIONS DEVELOPING IF CLOUDS CLEAR AND WINDS GO CALM
FOR A BRIEF PERIOD AROUND SUNRISE...HOWEVER AT THIS POINT THERE IS
NO SUPPORT FROM GUIDANCE...SO I AM NOT GOING TO INCLUDE IN THE
TAFS THIS CYCLE. THUNDERSTORM ACTIVITY OVER CENTRAL COLORADO WILL
TRANSITION EASTWARD THROUGH THIS EVENING...HOWEVER AT THIS TIME IT
APPEARS TO REMAIN OUTSIDE THE VICINITY OF EITHER TERMINAL.
THUNDERSTORMS WILL BE POSSIBLE AGAIN TUESDAY...HOWEVER COVERAGE
DURING THE CURRENT TAF PERIOD IS STILL IN QUESTION. WINDS WILL
LIKELY REMAIN GUSTY AT KGLD THIS EVENING AND SHOULD SHIFT FROM THE
SOUTH TO THE NORTHEAST AT BOTH TERMINALS LATE THIS
EVENING/OVERNIGHT AS A COLD FRONT MOVES THROUGH THE REGION. BY
TOMORROW MORNING WINDS SHOULD BE LESS THAN 12KT AT BOTH TERMINALS.
&&
.FIRE WEATHER...
ISSUED AT 237 PM MDT MON SEP 9 2013
NEAR CRITICAL FIRE WEATHER CONDITIONS HAVE DEVELOPED ACROSS PORTIONS
OF THE REGION THIS AFTERNOON. HOT TEMPERATURES AND LOW DEWPOINTS
HAVE LEAD TO RELATIVE HUMIDITIES DROPPING OFF INTO THE 15-25 PERCENT
RANGE. WINDS HAVE BEEN GUSTY AND A FEW LOCATIONS WERE BARELY MEETING
CRITERIA. HOWEVER...WHETHER OR NOT THE CONDITIONS WOULD LAST THE
FULL THREE HOURS TO MEET WARNING CRITERIA HAS BEEN PROBLEMATIC AS
THE WINDS HAVE BEEN BOUNCING UP AND DOWN THIS AFTERNOON. IN
ADDITION...A SLIGHT RISE IN DEWPOINTS FROM SOUTH TO NORTH HAS BEEN
NOTED AS A MORE MOIST AIR MASS ADVECTS IN FROM THE SOUTH. AS A
RESULT...CONFIDENCE WAS NOT QUITE HIGH ENOUGH TO GO AHEAD AND
ISSUE A RED FLAG WARNING FOR REDWILLOW...HITCHCOCK...DECATUR...
HOXIE...SHERIDAN...THOMAS....ST FRANCIS AND SHERMAN COUNTIES. IF
IT BECOMES APPARENT THAT WINDS WILL STAY UP...A SHORT DURATION RED
FLAG WARNING MAY BE REQUIRED. WILL UPDATE THE FIRE WEATHER
FORECAST TO REFLECT THE LATEST TRENDS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...RRH
LONG TERM...024
AVIATION...DR
FIRE WEATHER...RRH
AREA FORECAST DISCUSSION
NWS TOPEKA KS
309 PM CDT Sun Sep 8 2013
.SHORT TERM...(This Evening through Monday)
Issued at 305 PM CDT SUN SEP 8 2013
At 2 PM, a weak surface trough was oriented from east to west across
northern Kansas on Sunday afternoon, co-located with the axis of
warmest 850 temperatures. A very weak front/outflow boundary with
minimal convergence in the low levels was stationary within 30 miles
of the Nebraska border as well, with a cluster of showers and
thunderstorms in extreme northeast Kansas and northwest Missouri.
Temperatures just to the south of the weak surface boundary have
become extremely warm, ranging from 99 to 104 degrees early this
afternoon, and while some drier air has mixed to the surface,
dewpoints remain in the lower to middle 60s. These conditions along
with the expectation for further heating through 4 PM have prompted
issuance of a heat advisory for heat index values in the 104 to 107
range.
Aside from the heat, potential for more vigorous thunderstorm
development is the other forecast focus today. The most recent runs
of the HRRR and NMM models continue to suggest thunderstorm
development on the warm side of the weak surface front by middle to
late afternoon, potentially linked to any outflow moving southwest
out of ongoing convection in NW Missouri. These storms are not
expected to be particularly organized or strong owing to only weak
to moderate CAPE and very weak vertical shear. However, it would
seem to be a rather favorable setup for microbursts given the dry
adiabatic to superadiabatic lapse rates from the surface to 700 hpa
and favorable downdraft CAPE. The primary uncertainty lies in
whether storms will actually develop over the deeply mixed airmass
as parcels would need to be lifted through a very deep mixed layer
before freely convecting. The best chance for storms would seem to
be northeast of a line from Belleville to Junction City to Ottawa.
Any storms should come to an end by 10 PM. Temperatures will fall
off nicely but a south breeze is expected to persist through the
night and will probably keep low temps in the low to mid 70s. Monday
will be quite hot once again, but with the upper ridge progressing
east of the area, 850 temps are forecast to drop by 2 to 3 degrees
from Sunday and highs may hold in the middle to upper 90s. Southwest
winds will be quite a bit stronger than Sunday with an increasing
pressure gradient. The southwest flow should also support greater
dry air advection into the forecast area which will probably support
very high fire danger with any dry vegetation.
Barjenbruch
.LONG TERM...(Monday Night through Sunday)
Issued at 305 PM CDT SUN SEP 8 2013
Monday night upper level trough progresses eastward through the
northern plains. As this system pushes into the Great Lakes region a
cold front will move southward into the region. Temperatures at 850
will cool significantly over the central plains as the shortwave
continues eastward and the upper high shifts into the OH river
valley. High temperatures reach the mid 90s area wide on Tuesday.
The front will approach the cwa on Tuesday evening and there is a
slight chance for showers and thunderstorms along the front mainly
across southern NE with an outside chance of reaching the northern
counties. Overnight Tuesday the front sags south into the cwa
increasing the chances for storms north of interstate 70s as the
progress of the front slows down. Due to cloud cover associated with
the possible precip high temperatures on Wednesday could remain in
the upper 80s to low 90s.
The front continues to slowly push south across the cwa therefore
have maintains pops through Friday. Convergence along the front and
upper level forcing appears to be rather weak, but cooler mid level
temps will allow for a weaker cap in place. Front exits the area
sometime on Thursday night or Friday as a shortwave digs southeast
through the eastern longwave trough. A surface high pressure will
build northeast of the region and likely control how far the front
is pushed southward. Once the front passes return flow isentropic
lift may generate precip mainly across central and western KS
possible spreading into our western counties. Next weekend another
front will possibly move into the central plains. Temperatures look
to gradually cool behind the front with high temperatures in the
upper 70s to low 80s by Friday, and low temperatures generally in
the upper 50s to low 60s.
&&
.AVIATION...(For the 18Z TAFs through 18Z Monday Afternoon)
Issued at 1202 PM CDT SUN SEP 8 2013
Expect VFR conditions with scattered clouds based around 12000
feet, and a light southwest breeze less than 10 kts. There is a
small chance for TS to develop near TOP/FOE...and perhaps as far
west as MHK...between 19Z and 22Z. If TS are able to develop, very
localized areas of strong and variable downburst winds would be
possible in close proximity to storms.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY until 7 PM CDT this evening FOR KSZ021>024-026-036-
038>040-054>056-058-059.
&&
$$
SHORT TERM...Barjenbruch
LONG TERM...Sanders
AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS JACKSON KY
747 PM EDT MON SEP 9 2013
.UPDATE...
ISSUED AT 747 PM EDT MON SEP 9 2013
AS ANTICIPATED SHOWERS HAVE ALL DISSIPATED...LEAVING BEHIND MAINLY
CLEAR SKIES FOR THE REMAINDER OF THE NIGHT. WILL UPDATE FORECAST TO
REFLECT LESS CLOUD COVER OVERNIGHT AS WELL AS ADJUSTING LOWS DOWN A
TAD TOWARDS WHAT WE SAW LAST NIGHT. THIS SHOULD YIELD ANOTHER NIGHT
OF VALLEY FOG WITH DEWPOINTS ACTUALLY RUNNING A FEW DEGREES HIGHER
THAN YESTERDAY AT THIS TIME.
UPDATE ISSUED AT 553 PM EDT MON SEP 9 2013
A FEW SHOWERS AND THUNDERSTORMS HAVE DEVELOPED NORTHWARD INTO SOUTH
CENTRAL KENTUCKY...BASICALLY EASTERN WAYNE COUNTY/MCCREARY
COUNTY...NORTH INTO EASTERN PULASKI COUNTY. BASED ON SATELLITE...THIS
ACTIVITY SHOULD REMAIN CONFINED TO THESE AREAS OVER THE NEXT HOUR OR
TWO BEFORE WEAKENING AND DISSIPATING AS THE SUN GOES DOWN. THIS
SHOULD ALLOW ACTIVITY TO DIE OFF BY ROUGHLY 00Z. UPDATED NDFD GRIDS
TO REFINE THE POPS...BUT WILL NOT ISSUE A NEW ZFP WITH THE ISOLATED
NATURE OF THIS ACTIVITY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 340 PM EDT MON SEP 9 2013
18Z SFC ANALYSIS SHOWS WEAK HIGH PRESSURE IN PLACE OVER EAST KENTUCKY
WITH LOW PRESSURE FOUND OFF TO THE NORTHWEST. A DOME OF HIGHER
HEIGHTS IS BUILDING OVER THE REGION AND THIS HAS HELPED TO CONTRIBUTE
TO A VERY WARM LATE SUMMER DAY ACROSS EAST KENTUCKY WITH TEMPS
APPROACHING 90 DEGREES. PRETTY HIGH DEWPOINTS IN THE MID AND UPPER
60S ARE MAKING IT FEEL EVEN WARMER...IN ADDITION TO PROVIDING AN
UNCOMFORTABLE HUMIDITY LEVEL. HERE AT PEAK HEATING...A FEW OF THE CU
HAVE MANAGED TO GET DEEP ENOUGH THAT A SHOWER OR THUNDERSTORM WILL
BE POSSIBLE...MAINLY ALONG OUR SOUTHERN AND EASTERN BORDERS.
OTHERWISE...SKIES ARE MOSTLY CLEAR AND THE CU SHALLOW.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
DEPICTING A MODERATELY STRONG RIDGE PUSHING INTO THE LOWER OHIO
VALLEY AND ACROSS TO THE MID ATLANTIC COAST. THIS RIDGE WILL NOT BE
COMPLETELY FREE OF ENERGY OR PROHIBITIVELY WARM AT MID LEVELS...
THOUGH...SO ITS ABILITY TO PUT A CAP ON CONVECTION WILL BE LIMITED.
IN THIS KIND OF ENVIRONMENT...THE MESOSCALE WILL DOMINATE FOR WEATHER
SPECIFICS SO HAVE FAVORED A MORE SUBDUED VERSION OF THE NAM12 WITH
INPUT FROM THE HRRR IN THE NEAR TERM. ALSO FAVORED AN ENHANCED
DIURNAL TRACE FOR POPS.
SENSIBLE WEATHER WILL FEATURE MORE IN THE WAY OF PERSISTENCE THROUGH
WEDNESDAY MORNING. AT NIGHT...WE CAN EXPECT A FADE OUT OF THE
DAYTIME CLOUDS AND PATCHY FOG...LOCALLY DENSE IN THE VALLEYS...
DEVELOPING BY DAWN. HIGH DEWPOINTS WILL KEEP THERE FROM BEING MUCH OF
A RIDGE TO VALLEY TEMP SPLIT BOTH TONIGHT AND TUESDAY NIGHT. FOR THE
DAY TUESDAY...IT WILL BE ANOTHER WARM AND HUMID ONE WITH A SMALL
CHANCE OF SHOWERS AND THUNDERSTORMS DEVELOPING WITH PEAK HEATING...
DESPITE THE RIDGING ALOFT.
JUMP STARTED THE TD AND WIND GRIDS WITH CONSSHORT DATA THROUGH 12Z
TUESDAY AND THE CONSALL THEREAFTER. FOR TEMPERATURES...PREFERRED THE
OBS DATABASE AS A GUIDE FOR THE DIURNAL CURVE AND MODIFIED CONSALL
FOR MAX AND MIN TEMPS...TEMPERING THE TOO WARM GRIDDED MOS HIGHS ON
TUESDAY WITH SOME RAW MODEL OUTPUT. AS FOR POPS...ENDED UP PRETTY
CLOSE TO AN AVERAGE OF THE GUIDANCE THROUGH THE SHORT TERM PERIOD.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 245 PM EDT MON SEP 9 2013
THE MODELS ALL AGREE THAT WEDNESDAY AND THURSDAY WILL BE THE ACTIVE
DAYS OF THE EXTENDED PERIOD. A SERIES OF WEATHER SYSTEMS...BOTH
SURFACE FRONTS AND TROUGHS OF LOW PRESSURE ALOFT...WILL BRING
SHOWERS AND THUNDERSTORMS TO EASTERN KENTUCKY DURING THE MIDDLE OF
THE WEEK. THE MORE POTENT WEATHER MAKER WILL BE A SIGNIFICANT COLD
FRONT THAT IS EXPECTED TO MOVE ACROSS THE AREA THURSDAY INTO
THURSDAY EVENING. THE FRONT WILL LIKELY BE SLOWED UP A BIT BY THE
HIGH TERRAIN OF EAST KENTUCKY FOR IT FINALLY EXITS THE AREA THURSDAY
EVENING. ONCE THE FRONT IS OUT OF THE AREA...A LARGE AND WELL
DEFINED AREA OF HIGH PRESSURE WILL MIGRATE SOUTHWARD OUT OF CANADA
AND THEN THE OHIO VALLEY...BEFORE FINALLY SETTLING OVER THE EASTERN
CONUS FROM FRIDAY ONWARD. THE AIR MASS ASSOCIATED WITH THIS RIDGE
WILL BRING VERY UNSEASONABLY COOL TEMPERATURES TO THE REGION FRIDAY
AND SATURDAY. HIGHS ON FRIDAY AND SATURDAY WILL ONLY BE TOPPING OUT
IN THE LOW TO MID 70S...BEFORE REBOUNDING A BIT ON SUNDAY...WHEN
HIGHS IN THE UPPER 70S TO AROUND 80 ARE EXPECTED. THE
GFS...ECMWF...AND NAEFS MODELS ALL BEGIN THE PERIOD WITH A LARGE
TROUGH OF LOW PRESSURE ALOFT ACROSS THE EASTERN CONUS...WITH A
STRONG RIDGE OF HIGH PRESSURE SETTING UP OUT WEST. THE MIDDLE OF THE
WEEK WILL FEATURE WARM AND WET WEATHER...WHILE THE END OF THE WEEK
AND THE UPCOMING WEEKEND WILL BE VERY COOL AND DRY AND FALL LIKE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 747 PM EDT MON SEP 9 2013
VFR CONDITIONS THIS EVENING WILL GIVE WAY TO MVFR/IFR FOG DEVELOPMENT
IN THE VALLEYS OVERNIGHT. SIMILAR TO THE LAST FEW NIGHTS...THIS FOG
WILL ONCE AGAIN IMPACT THE TAF SITES. WENT WITH SIMILAR FOG AS LAST
NIGHT IN THE TAFS SINCE CONDITIONS REMAIN VERY SIMILAR AND WOULD
EXPECT SIMILAR RESULTS. FOG WILL BURN OFF BY 14Z TOMORROW
MORNING...LEAVING BEHIND VFR CONDITIONS FOR THE REMAINDER OF THE DAY.
AN ISOLATED SHOWER OR THUNDERSTORM WILL BE POSSIBLE AGAIN...BUT NOT
ENOUGH CONFIDENCE TO INCLUDE IN THE FORECAST AT THIS TIME.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...KAS
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
335 PM EDT SUN SEP 8 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 335 PM EDT SUN SEP 8 2013
18Z SFC ANALYSIS SHOWS A COLD FRONT DISSIPATING OVER EAST KENTUCKY.
THIS BOUNDARY HAS NOT BROUGHT AN AIR MASS CHANGE AND HAS NOT BEEN
ABLE TO GENERATE MUCH IN THE WAY OF CONVECTION FOR EAST KENTUCKY...SO
FAR. HOWEVER...THERE ARE A FEW SHOWERS GOING UP NOT TOO FAR FROM
US. STILL THINK THAT A SOME SHOWERS AND POSSIBLY A THUNDERSTORM WILL
OCCUR OVER PARTS OF EAST KENTUCKY...MAINLY SOUTH OF JKL...THROUGH
SUNSET. SKIES HAVE BEEN PARTLY TO MOSTLY CLOUDY THROUGH THE AREA THIS
AFTERNOON WITH THE SUNSHINE HELPING TEMPERATURES CLIMB INTO THE LOWER
AND MID 80S IN MOST LOCATIONS. MEANWHILE...DEWPOINTS HAVE SLIPPED A
BIT...MIXING DOWN TO THE LOW TO MID 60S THOUGH THE WINDS HAVE BEEN
GENERALLY LIGHT.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH A SMALL SHORTWAVE PASSING
BY TO THE NORTHEAST TONIGHT...WHILE AN MCV WILL SLIP SOUTH WELL TO
THE WEST OF THE AREA. RIDGING THEN BUILDS BACK OVER THE AREA EARLY
MONDAY...RUNNING EAST OVER KENTUCKY DURING THE DAY AND INTO THE
NIGHT. WITH THE GOOD MODEL AGREEMENT...HAVE AGAIN FOLLOWED THE HIGHER
RESOLUTION NAM12 FOR DETAILS...ALONG WITH SOME HRRR INFLUENCE IN THE
NEAR TERM.
SENSIBLE WEATHER WILL FEATURE WIDELY SCATTERED SHOWERS AND THE ODD
THUNDERSTORM...FADING OUT BY SUNSET ALONG WITH MUCH OF THE CLOUDS.
THIS WILL SET THE STAGE FOR ANOTHER MILD NIGHT WITH PATCHY FOG
DEVELOPING TOWARD DAWN...MAINLY IN THE VALLEYS. THE RIDGE BUILDING
ALOFT ON MONDAY WILL WIPE OUT THE REMAINS OF THE FRONT AND LIMIT ANY
CONVECTION TO JUST A VERY SMALL THREAT ALONG THE VIRGINIA BORDER AT
PEAK HEATING. IT WILL ALSO BE A VERY WARM DAY WITH TEMPERATURES
APPROACHING 90 DEGREES IN SOME LOCATIONS BY LATE AFTERNOON. ANOTHER
MILD NIGHT WITH PATCHY VALLEY FOG FOLLOWS INTO TUESDAY MORNING.
AGAIN USED THE CONSSHORT AND ITS BIAS CORRECTED KIN TO JUMP START
THE TD AND WIND GRIDS THROUGH 12Z MONDAY AND THE CONSALL THEREAFTER.
FOR TEMPERATURES...PREFERRED THE OBS DATABASE AS A BASIS FOR THE
DIURNAL CURVE AND MODIFIED CONSALL FOR MAX AND MIN TEMPS. AGAIN DID
NOT DO TOO MUCH TERRAIN ADJUSTMENT AT NIGHT GIVEN THE HIGHER DEWS AND
SOME CLOUD COVER EXPECTED TO BE AROUND. AS FOR POPS...ENDED UP PRETTY
CLOSE TO AN AVERAGE OF THE GUIDANCE THROUGH THE SHORT TERM PERIOD.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 320 PM EDT SUN SEP 8 2013
THE MODELS WERE NOT IN THE BEST AGREEMENT THIS TIME AROUND WITH THE
SURFACE DETAILS. THE UPPER AIR PATTERN...HOWEVER...WAS GENERALLY THE
SAME BETWEEN THE HPC...GFS...ECWMF MODEL OUTPUTS. THE PERIOD IS
PROGGED TO START OUT WITH A LARGE RIDGE OF HIGH PRESSURE PARKED
ACROSS THE SOUTHEASTERN CONUS. WEAK MARGINALLY MOIST FLOW AROUND THE
WESTERN EDGE OF THE HIGH COULD LEAD TO ISOLATED SHOWER AND STORM
ACTIVITY TUESDAY AFTERNOON AND EVENING. THE GFS AND SREF WERE ALSO
ON BOARD WITH THIS PATTERN. BASED ON THE LATEST MEXMOS AND ECEMOS
GUIDANCE...THERE WOULD BE A CHANCE OF RAIN IN THE FORECAST EACH DAY
FROM TUESDAY THROUGH THURSDAY NIGHT. THAT BEING SAID...AND WITH THE
LATEST RUNS OF THE GFS AND ECWMF BOTH IN GOOD AGREEMENT...DECIDE TO
INCLUDE A CHANCE OF RAIN IN THE FORECAST THROUGH LATE THURSDAY
NIGHT. THE BEST CHANCE FOR RAIN LOOKS TO BE THURSDAY AND THURSDAY
EVENING...AS A FAIRLY STRONG COLD FRONT MOVES ACROSS THE AREA.
TEMPERATURES AHEAD OF THE FRONT WILL BE QUITE WARM...WITH HIGHS
TOPPING OUT IN THE MID TO UPPER 80S ACROSS THE AREA TUESDAY THROUGH
THURSDAY. EASTERN KENTUCKY WILL BE ENTRENCHED IN A PERSISTENT
SOUTHERLY FLOW REGIME AS AN AREA OF HIGH PRESSURE REMAINS IN PLACE
ACROSS THE AREA. THE PRESENCE OF CLOUDS AND ISOLATED SHOWERS AND
STORMS SHOULD BE ENOUGH TO KEEP TEMPERATURES AROUND EASTERN KENTUCKY
FROM REACHING THE EXTREMELY WARM MOS VALUES(THE LATEST MEXMOS HAS A
FEW LOCATIONS AROUND THE AREA REACHING THE LOWER 90S ON TUESDAY). A
DRAMATIC COOL DOWN IS IN STORE FOR THE END OF THE WEEK...AS A COOL
AND DRY CANADIAN AIR MASS SETTLES OVER THE AREA BEHIND THE DEPARTING
COLD FRONT. DAYTIME HIGHS ON FRIDAY AND SATURDAY WILL NOT GET OUT
OF THE 70S...WITH HIGHS ON SATURDAY POSSIBLE ONLY MAKING IT INTO THE
LOW TO MID 70S. OVERNIGHT LOWS WILL BE QUITE WARM AT FIRST...WITH
VALUES AROUND 70 COMMON TO START THE PERIOD. THINGS WILL COOL OFF
QUITE A BIT AFTER THAT...WITH LOWS AROUND 60 POSSIBLE THURSDAY
NIGHT...AND DROPPING INTO THE LOWER 50S FRIDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 200 PM EDT SUN SEP 8 2013
A DISSIPATING COLD FRONT WILL BRING A SMALL THREAT OF CONVECTION TO
THE AREA THIS AFTERNOON. FOR THIS...HAVE INCLUDED SOME VCSH IN THE
TAFS. ONCE WE LOSE THE DAYTIME HEATING...SKIES WILL CLEAR OUT WITH
SOME MVFR FOG LIKELY SEEN ONCE AGAIN BETWEEN 06 AND 12Z AT THE TAF
SITES...LOCALLY DENSE THOUGH IN THE EASTERN VALLEYS. CANNOT RULE OUT
A STRAY SHOWER OR THUNDERSTORM ON MONDAY...THOUGH THEY WILL LIKELY BE
FEW AND FAR BETWEEN. WINDS WILL BE LIGHT AND VARIABLE THROUGHOUT THE
PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
200 PM EDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 155 PM EDT SUN SEP 8 2013
SHOWERS ARE STARTING TO DEVELOP OVER THE CUMBERLAND VALLEY BUT ARE
STILL RATHER ISOLATED. HAVE UPDATED THE GRIDS MAINLY FOR NEAR TERM
POPS...SKY COVER...AND TO MATCH UP THE T/TD ONES TO THE OBS AND
TRENDS. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 1100 AM EDT SUN SEP 8 2013
14Z SFC ANALYSIS SHOWS A WEAK COLD FRONT POISED TO DROP THROUGH EAST
KENTUCKY TODAY. A SMATTERING OF LIGHT SHOWERS MOVED ACROSS THE AREA
EARLY IN THE MORNING OUT AHEAD OF THIS...ALONG WITH PATCHY FOG...AND
SKIES HAVE TEMPORARILY CLEARED IN THEIR WAKE. TEMPERATURES AND
DEWPOINTS ARE FAIRLY UNIFORM THROUGH THE AREA GENERALLY IN THE LOWER
70S AND UPPER 60S...RESPECTIVELY. THE LATEST NAM12 AND HRRR INDICATE
THAT THE SOUTHERN PARTS OF THE CWA WILL HAVE THE BEST CHANCE OF
SEEING A REDEVELOPMENT OF SHOWERS AND ISOLATED STORMS BY MID
AFTERNOON AS THE FRONT SETTLES ON THROUGH. HAVE GEARED THE NEAR TERM
FORECAST GRIDS TO THIS IDEA...ALLOWING THE INSTABILITY TO BUILD
BEFORE INTRODUCING THUNDER INTO THE WX ONES. MOST PLACES WILL STAY
DRY...WARM..AND HUMID TODAY...THOUGH. A FORTHCOMING ZFP UPDATE WILL
REMOVE THE MORNING FOG WORDING. THE FRESHENED GRIDS HAVE BEEN SENT TO
THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 657 AM EDT SUN SEP 8 2013
ISOLATED SHOWERS ARE DIMINISHING ACROSS THE AREA AS THE ISENTROPIC
FORCING EASES UP. WILL LET THE FORECAST RIDE AS A FEW SHOWERS MAY BE
SEEN AFTER 12Z BEFORE DRYING UP COMPLETELY UNTIL WE HEAT UP THIS
AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 254 AM EDT SUN SEP 8 2013
THE LATEST SURFACE MAP FEATURES A SURFACE COLD FRONT ALIGNED FROM
NORTHERN NEW ENGLAND DOWN THROUGH THE NORTHERN OHIO VALLEY...WITH AN
AREA OF SURFACE HIGH PRESSURE CONGEALED ACROSS THE SOUTHEASTERN
CONUS. ISENTROPIC LIFT OUT AHEAD OF THE FRONT HAS ALLOWED FOR SOME
NOCTURNAL SHOWER ACTIVITY ALONG AND SOUTH OF THE OHIO
RIVER...INCLUDING PORTIONS OF EASTERN KENTUCKY. THE LATEST NAM12
SEEMS TO HAVE A REASONABLE HANDLE ON THE ISENTROPIC LIFT...ALTHOUGH
ITS QPF IS NOT BEEFY ENOUGH COMPARED TO REALITY.
THE MODELS REMAIN IN GOOD AGREEMENT THROUGH THE SHORT TERM...ALLOWING
THE COLD FRONT TO MAKE IT INTO THE COMMONWEALTH THIS AFTERNOON. POPS
HAVE COME IN LOWER...ESPECIALLY FROM THE NAM12. WILL STICK WITH AT
LEAST ISOLATED CHANCES...ALTHOUGH WILL RESTRICT THE SCATTERED
POTENTIAL TO THE SOUTHEAST TERRAIN COUNTIES GIVEN THE DOWNWARD TREND.
HIGHS WILL BE A BIT WARMER THAN YESTERDAY...WITH MID 80S FOR MOST
LOCATIONS...AND A FEW SPOTS REACHING THE UPPER 80S.
THE FRONT WILL DISSOLVE ACROSS THE AREA INTO THIS EVENING...AND
EXPECT A QUICK DIE OFF IN THE CONVECTION WITH THE LOSS OF HEATING.
LOWS TONIGHT WILL REFLECT THE INCREASING HUMIDITY ACROSS THE
AREA...WITH MID TO UPPER 60S EXPECTED. AN UPPER LEVEL RIDGE WILL MOVE
IN FROM THE WEST ON MONDAY...SO EXPECT THIS TO KEEP A LID ON THE
CONVECTION FOR THE MOST PART...ALTHOUGH COULD SEE A STRAY SHOWER OR
STORM GO UP ALONG THE SOUTHEAST TERRAIN. HIGHS WILL BE A BIT WARMER
STILL...WITH UPPER 80S EXPECTED AND A FEW SPOTS FLIRTING WITH THE 90
DEGREE MARK.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 346 AM EDT SUN SEP 8 2013
THE MODELS START OUT IN GOOD AGREEMENT WITH AND UPPER RIDGE OVER THE
SOUTHEAST WITH AN UPPER TROUGH MOVING EAST ACROSS THE ROCKIES. THERE
IS A BATTLE OF SORTS WITH THE UPPER RIDGE WHICH TRIES TO STAY IN
PLACE AS THE TROUGH TRIES TO DISPLACE IT. BY WEDNESDAY MORNING A COLD
FRONT EXTENDS FROM ACROSS LAKE HURON AND ENDS OVER COLORADO. THE UPPER
RIDGE IS DISPLACED A LITTLE EASTWARD. ALL THIS WHILE...SOME WARM
MOIST AIR IS WORKING ITS WAY INTO THE AREA. THIS WARM MOIST AIR WILL
BE RESPONSIBLE FOR SOME ISOLATED SHOWERS AND THUNDERSTORMS ON TUESDAY
AND THEN SOME SCATTERED STORMS ON WEDNESDAY AFTERNOON AND EVENING.
THE FRONT WILL BE MOVING ACROSS THE AREA ON THURSDAY. CHOSE TO GO
WITH THE SLOWER ECMWF MODEL FOR THE TIMING OF THE FRONT. THE FRONT
WILL BRING A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS TO THE AREA.
THE FRONT WILL BE THROUGH THE AREA BY FRIDAY MORNING AND A SURFACE
HIGH PRESSURE SYSTEM WILL MOVE IN AND DOMINATE UNTIL THE END OF THE
PERIOD. THE OUTLOOK FOR NEXT WEEKEND IS GOOD WITH DRY CONDITIONS AND
HIGH TEMPERATURES IN THE 70S. FOR TEMPS TENDED TO NUDGE TOWARD THE
COOLER MODELS FOR THE HIGH TEMPERATURES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 200 PM EDT SUN SEP 8 2013
A DISSIPATING COLD FRONT WILL BRING A SMALL THREAT OF CONVECTION TO
THE AREA THIS AFTERNOON. FOR THIS...HAVE INCLUDED SOME VCSH IN THE
TAFS. ONCE WE LOSE THE DAYTIME HEATING...SKIES WILL CLEAR OUT WITH
SOME MVFR FOG LIKELY SEEN ONCE AGAIN BETWEEN 06 AND 12Z AT THE TAF
SITES...LOCALLY DENSE THOUGH IN THE EASTERN VALLEYS. CANNOT RULE OUT
A STRAY SHOWER OR THUNDERSTORM ON MONDAY...THOUGH THEY WILL LIKELY BE
FEW AND FAR BETWEEN. WINDS WILL BE LIGHT AND VARIABLE THROUGHOUT THE
PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GEOGERIAN
LONG TERM...JJ
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1100 AM EDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 1100 AM EDT SUN SEP 8 2013
14Z SFC ANALYSIS SHOWS A WEAK COLD FRONT POISED TO DROP THROUGH EAST
KENTUCKY TODAY. A SMATTERING OF LIGHT SHOWERS MOVED ACROSS THE AREA
EARLY IN THE MORNING OUT AHEAD OF THIS...ALONG WITH PATCHY FOG...AND
SKIES HAVE TEMPORARILY CLEARED IN THEIR WAKE. TEMPERATURES AND
DEWPOINTS ARE FAIRLY UNIFORM THROUGH THE AREA GENERALLY IN THE LOWER
70S AND UPPER 60S...RESPECTIVELY. THE LATEST NAM12 AND HRRR INDICATE
THAT THE SOUTHERN PARTS OF THE CWA WILL HAVE THE BEST CHANCE OF
SEEING A REDEVELOPMENT OF SHOWERS AND ISOLATED STORMS BY MID
AFTERNOON AS THE FRONT SETTLES ON THROUGH. HAVE GEARED THE NEAR TERM
FORECAST GRIDS TO THIS IDEA...ALLOWING THE INSTABILITY TO BUILD
BEFORE INTRODUCING THUNDER INTO THE WX ONES. MOST PLACES WILL STAY
DRY...WARM..AND HUMID TODAY...THOUGH. A FORTHCOMING ZFP UPDATE WILL
REMOVE THE MORNING FOG WORDING. THE FRESHENED GRIDS HAVE BEEN SENT TO
THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 657 AM EDT SUN SEP 8 2013
ISOLATED SHOWERS ARE DIMINISHING ACROSS THE AREA AS THE ISENTROPIC
FORCING EASES UP. WILL LET THE FORECAST RIDE AS A FEW SHOWERS MAY BE
SEEN AFTER 12Z BEFORE DRYING UP COMPLETELY UNTIL WE HEAT UP THIS
AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 254 AM EDT SUN SEP 8 2013
THE LATEST SURFACE MAP FEATURES A SURFACE COLD FRONT ALIGNED FROM
NORTHERN NEW ENGLAND DOWN THROUGH THE NORTHERN OHIO VALLEY...WITH AN
AREA OF SURFACE HIGH PRESSURE CONGEALED ACROSS THE SOUTHEASTERN
CONUS. ISENTROPIC LIFT OUT AHEAD OF THE FRONT HAS ALLOWED FOR SOME
NOCTURNAL SHOWER ACTIVITY ALONG AND SOUTH OF THE OHIO
RIVER...INCLUDING PORTIONS OF EASTERN KENTUCKY. THE LATEST NAM12
SEEMS TO HAVE A REASONABLE HANDLE ON THE ISENTROPIC LIFT...ALTHOUGH
ITS QPF IS NOT BEEFY ENOUGH COMPARED TO REALITY.
THE MODELS REMAIN IN GOOD AGREEMENT THROUGH THE SHORT TERM...ALLOWING
THE COLD FRONT TO MAKE IT INTO THE COMMONWEALTH THIS AFTERNOON. POPS
HAVE COME IN LOWER...ESPECIALLY FROM THE NAM12. WILL STICK WITH AT
LEAST ISOLATED CHANCES...ALTHOUGH WILL RESTRICT THE SCATTERED
POTENTIAL TO THE SOUTHEAST TERRAIN COUNTIES GIVEN THE DOWNWARD TREND.
HIGHS WILL BE A BIT WARMER THAN YESTERDAY...WITH MID 80S FOR MOST
LOCATIONS...AND A FEW SPOTS REACHING THE UPPER 80S.
THE FRONT WILL DISSOLVE ACROSS THE AREA INTO THIS EVENING...AND
EXPECT A QUICK DIE OFF IN THE CONVECTION WITH THE LOSS OF HEATING.
LOWS TONIGHT WILL REFLECT THE INCREASING HUMIDITY ACROSS THE
AREA...WITH MID TO UPPER 60S EXPECTED. AN UPPER LEVEL RIDGE WILL MOVE
IN FROM THE WEST ON MONDAY...SO EXPECT THIS TO KEEP A LID ON THE
CONVECTION FOR THE MOST PART...ALTHOUGH COULD SEE A STRAY SHOWER OR
STORM GO UP ALONG THE SOUTHEAST TERRAIN. HIGHS WILL BE A BIT WARMER
STILL...WITH UPPER 80S EXPECTED AND A FEW SPOTS FLIRTING WITH THE 90
DEGREE MARK.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 346 AM EDT SUN SEP 8 2013
THE MODELS START OUT IN GOOD AGREEMENT WITH AND UPPER RIDGE OVER THE
SOUTHEAST WITH AN UPPER TROUGH MOVING EAST ACROSS THE ROCKIES. THERE
IS A BATTLE OF SORTS WITH THE UPPER RIDGE WHICH TRIES TO STAY IN
PLACE AS THE TROUGH TRIES TO DISPLACE IT. BY WEDNESDAY MORNING A COLD
FRONT EXTENDS FROM ACROSS LAKE HURON AND ENDS OVER COLORADO. THE UPPER
RIDGE IS DISPLACED A LITTLE EASTWARD. ALL THIS WHILE...SOME WARM
MOIST AIR IS WORKING ITS WAY INTO THE AREA. THIS WARM MOIST AIR WILL
BE RESPONSIBLE FOR SOME ISOLATED SHOWERS AND THUNDERSTORMS ON TUESDAY
AND THEN SOME SCATTERED STORMS ON WEDNESDAY AFTERNOON AND EVENING.
THE FRONT WILL BE MOVING ACROSS THE AREA ON THURSDAY. CHOSE TO GO
WITH THE SLOWER ECMWF MODEL FOR THE TIMING OF THE FRONT. THE FRONT
WILL BRING A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS TO THE AREA.
THE FRONT WILL BE THROUGH THE AREA BY FRIDAY MORNING AND A SURFACE
HIGH PRESSURE SYSTEM WILL MOVE IN AND DOMINATE UNTIL THE END OF THE
PERIOD. THE OUTLOOK FOR NEXT WEEKEND IS GOOD WITH DRY CONDITIONS AND
HIGH TEMPERATURES IN THE 70S. FOR TEMPS TENDED TO NUDGE TOWARD THE
COOLER MODELS FOR THE HIGH TEMPERATURES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 657 AM EDT SUN SEP 8 2013
IFR OR WORSE FOG WILL BURN OFF BY AROUND 13Z. A FEW SHOWERS WILL BE
SEEN THROUGH 14Z...MAINLY ALONG AND SOUTH OF THE HAL ROGERS PARKWAY
AND HIGHWAY 80 CORRIDORS...BEFORE DIMINISHING. A COLD FRONT WILL
BRING A SMALL THREAT OF CONVECTION TO THE AREA THIS AFTERNOON. WILL
ALLOW FOR SOME VCSH IN THE TAFS. ONCE WE LOSE HEATING...SKIES WILL
CLEAR OUT WITH FOG LIKELY SEEN ONCE AGAIN BETWEEN 06 AND 12Z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GEOGERIAN
LONG TERM...JJ
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
201 AM EDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 201 AM EDT SUN SEP 8 2013
SOME ISENTROPIC LIFT DEVELOPING OUT AHEAD THE OHIO VALLEY COLD FRONT
HAS ALLOWED FOR SOME ISOLATED SHOWERS TO MOVE IN FROM THE NORTHWEST.
HAVE UPDATED TO INCLUDE THIS MENTION...ALTHOUGH DO NOT FORESEE THESE
GETTING SOUTH OF AN IRVINE TO JACKSON TO PIKEVILLE LINE. FRESHENED UP
THE HOURLY TEMPERATURES...DEW POINTS...AND SKY COVER AS WELL.
UPDATE ISSUED AT 740 PM EDT SAT SEP 7 2013
BASED ON THE LATEST HRRR AND 18Z NAM...HAVE BACKED OFF ON POPS LATE
TONIGHT WITH VERY LITTLE CHANCE OF SEEING MUCH ACTIVITY UNTIL AFTER
12Z. IN FACT...CEILINGS TO THE NORTH ARE STILL 12KFT OR HIGHER WITH
VERY LITTLE EVIDENCE OF CEILINGS COMING DOWN. MOISTURE APPEARS VERY
LIMITED IN THE LOWER LEVELS AND GIVEN THE LACK OF INSTABILITY...HARD
TO SEE MUCH SHOWER ACTIVITY DEVELOPING OVERNIGHT. ALSO SPED UP THE
TEMPERATURE DROP OFF THIS EVENING AS CLEAR SKIES SHOULD ALLOW FOR A
QUICK DROP IN TEMPERATURES THIS EVENING...WITH SOME OF THE VALLEYS
POSSIBLY SINKING INTO THE 50S BY LATE EVENING PRIOR TO THE ARRIVAL OF
THE MID/HIGH CLOUDS FROM THE NORTH. CLOUDS SHOULD EVENTUALLY SLOW
DOWN THE TEMPERATURE FALL FOR THE SECOND HALF OF THE
NIGHT...ESPECIALLY IN THE NORTH. CLOUDS WILL EVENTUALLY REACH THE
TENNESSEE BORDER BY 09Z. ZFP UPDATE WILL BE OUT SOON...BUT NDFD GRIDS
HAVE ALREADY BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 245 PM EDT SAT SEP 7 2013
18Z SFC ANALYSIS SHOWS RETREATING HIGH PRESSURE THROUGH EAST KENTUCKY
MAKING FOR A VERY PLEASANT...WARM...AND MOSTLY SUNNY DAY.
TEMPERATURES HAVE GENERALLY CLIMBED INTO THE LOWER 80S ON THEIR WAY
TO THE MID 80S. MEANWHILE...DEWPOINTS ACROSS THE AREA ARE HOLDING IN
THE LOWER 60S FOR MOST OF THE AREA...MID 60S NEAR THE TENNESSEE
BORDER...UPPER 50S NORTH OF INTERSTATE 64.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PART OF
THE FORECAST WITH A LARGE RIDGE TO THE IMMEDIATE WEST OF THE AREA AND
TROUGHING TO THE NORTHEAST. BETWEEN THESE...A COUPLE OF SHORTWAVES
WILL PASS OVER THE OHIO VALLEY THROUGH SUNDAY NIGHT. ONE OF THESE...
PASSES BY JUST TO THE EAST ON SUNDAY AND WILL BRIEFLY BUCKLE THE
WESTERN RIDGE THROUGH MIDDAY SUNDAY. GIVEN THE MODEL AGREEMENT...HAVE
FOLLOWED THE HIGHER RESOLUTION NAM12 FOR WX SPECIFICS.
SENSIBLE WEATHER WILL FEATURE A MILD NIGHT WITH HIGHER DEWPOINTS AND
MORE CLOUDS KEEPING THE VALLEYS FROM DROPPING OFF AS MUCH AS LAST
NIGHT. LIKEWISE...EXPECT THE FOG TO BE LESS PREVALENT IN THE ALL BUT
THE DEEPER VALLEYS BY MORNING. THE APPROACHING COLD FRONT WILL BRING
A THREAT OF SHOWERS OR THUNDERSTORMS TO NORTHERN PARTS OF EAST
KENTUCKY BY DAWN. THE FRONT DROPS THROUGH THE CWA DURING THE DAY
SUNDAY AND COMBINED WITH PEAK HEATING WILL BRING A BETTER CHANCE OF
SHOWERS AND THUNDERSTORMS TO THE ENTIRE AREA. RIDGING BUILDS BACK IN
ALOFT BY EVENING...THOUGH...AS THE MID LEVEL SHORTWAVE PASSES AND
THIS SHOULD PUT AN END TO THE CONVECTION THREAT SHORTLY AFTER 00Z.
ANOTHER MILD NIGHT FOLLOWS WITH PATCHY VALLEY FOG ANTICIPATED BY
DAWN.
USED THE CONSSHORT AND ITS BC BROTHER TO JUMP START THE TD AND WIND
GRIDS THROUGH 12Z SUNDAY...CONSALL THEREAFTER. FOR TEMPERATURES...
USED THE OBS DATABASE AS A BASIS FOR THE DIURNAL CURVE AND MODIFIED
CONSALL MAX AND MIN TEMPS...NOT TOO MUCH TERRAIN ADJUSTMENT AT NIGHT
GIVEN THE BUILDING CLOUDS TONIGHT AND FRONTAL CLOUDS SUNDAY NIGHT. AS
FOR POPS...ENDED UP MOST SIMILAR TO THE MET NUMBERS THROUGH THE SHORT
TERM PERIOD.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 245 PM EDT SAT SEP 7 2013
STILL DECENT AGREEMENT AMONGST THE EXTENDED MODELS FOR DAYS 3 THRU 7
OF THE FORECAST. HIGH PRESSURE WILL BE THE DOMINANT FEATURE ON
MONDAY...WITH PARTLY CLOUDY SKIES AND DRY CONDITIONS EXPECTED. A
SERIES OF WEAK WEATHER SYSTEM WILL BRING ISOLATED TO SCATTERED
SHOWERS AND STORMS TO THE AREA AS THEY MOVE ACROSS THE EASTERN THIRD
OF THE CONUS TUESDAY THROUGH THURSDAY. THE BEST CHANCE OF RAIN WILL
LIKELY OCCUR ON THURSDAY AS A SLUGGISH FRONTAL BOUNDARY INTERACTS
WITH THE TERRAIN OF EASTERN KENTUCKY. TEMPERATURES WILL TOP OUT
MOSTLY IN THE MID TO UPPER 80S THROUGH THURSDAY. HIGHS ON FRIDAY AND
SATURDAY WILL BE MUCH COOLER BEHIND THE DEPARTING FRONT...WITH HIGHS
TOPPING OUT MOSTLY IN THE MID TO UPPER 70S EACH DAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 201 AM EDT SUN SEP 8 2013
AN APPROACHING COLD FRONT WILL BRING MOSTLY CLOUDY SKIES AS WELL AS A
FEW ISOLATED SHOWERS THROUGH THE DAWN. IFR OR WORSE FOG WILL ALSO BE
SEEN...MAINLY ALONG THE DEEPER RIVER VALLEYS...ALTHOUGH LOZ HAS
ALREADY DROPPED DOWN TO IFR BRIEFLY. EXPECT IFR CONDITIONS AT LOZ
THROUGH AROUND 09Z BEFORE THE THICKENING CLOUDS ALLOW FOR SOME
IMPROVEMENT BETWEEN 09 AND 12Z. WILL KEEP IT VFR AT JKL AND SME WITH
SME HAVING A LOWER CROSSOVER TEMPERATURE FROM YESTERDAY AFTERNOON AND
JKL BEING A RIDGETOP. ISOLATED CONVECTION WILL THREATEN DURING THE
AFTERNOON ACROSS EASTERN KENTUCKY AS THE COLD FRONT WEAKENS AND MOVES
THROUGH THE AREA...HOWEVER WILL CONTINUE TO HOLD OFF ON ANY MENTION
IN THE TAFS FOR NOW...GIVEN THE LIMITED AREAL COVERAGE EXPECTED.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1149 PM EDT MON SEP 9 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 334 PM EDT MON SEP 9 2013
A WARM FRONT MOVED THROUGH WITH SOME HEAVY RAIN MONDAY MORNING.
THE RAIN IS GONE AND WARM AND HUMID WEATHER WILL BE AROUND UNTIL
TUESDAY NIGHT AND WEDNESDAY BEFORE A COLD FRONT USHERS IN SOME
VERY COOL TEMPERATURES FOR THE END OF THE WEEK.
&&
.UPDATE...
ISSUED AT 1023 PM EDT MON SEP 9 2013
UPDATED TO RAISE MIN TEMPS OVERNIGHT. WE CONTINUE TO WARM
ADVECT OVERNIGHT...WITH H9 TEMPS INCREASING TO AN AMAZING +28C
(83F)! FEEL SURFACE TEMPS WILL REMAIN FAIRLY STEADY AFTER 06Z...
MAINLY IN THE MID 70S...WITH A FEW LOW 70S FAR NORTH.
UPDATE ISSUED AT 619 PM EDT MON SEP 9 2013
WE HAVE ISSUED AN UPDATE TO ADD IN A FEW SHOWERS/ISOLATED STORMS
FOR THE NEXT COUPLE OF HOURS UP NORTH FOR OSCEOLA AND CLARE
COUNTIES. A FEW SHOWERS WERE OCCURRING NORTH OF THE CWFA NORTH OF
THE WARM FRONT AND INTERACTING WITH AN OLD REMNANT MCV COMING IN
FROM THE W/NW. IT APPEARS THESE SHOULD MOVE OUT IN THE NEXT COUPLE
OF HOURS...AND ALLOW FOR THE EXPECTED DRY NIGHT OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 334 PM EDT MON SEP 9 2013
FORECAST ISSUES IN THE NEAR TERM ARE POTENTIAL FOR SOME SHOWERS
THIS EVENING...MAX TEMPS ON TUESDAY AND TIMING PRECIP ALONG THE
FRONT TUESDAY NIGHT THROUGH WEDNESDAY.
AS FOR WHAT HAPPENED LAST NIGHT...THE STORMS CERTAINLY
OUTPERFORMED THE FORECAST QPF AS MID LEVEL INSTABILITY COMBINED
WITH STRONG MOISTURE ADVECTION AND ISENTROPIC LIFT NORTH OF THE
SFC WARM FRONT. IT APPEARS THE REMNANTS OF AN MCS HELPED FOCUS THE
CONVECTION AS WELL...WITH RADAR LOOPS SHOWING AN MCV CIRCULATION
MOVING SOUTHEAST ACROSS THE FORECAST AREA CONCURRENT WITH THE DEEP
CONVECTION.
AS FOR LATE THIS AFTERNOON AND EVENING...THE SFC WARM FRONT
WILL BE LIFTING NORTH ACROSS LOWER MICHIGAN AND THE HRRR IS SHOWING
SHOWERS BRUSHING THE NORTHERN FORECAST AREA AS AN MCS MOVES EAST
ACROSS THE UPPER PENINSULA. WILL HAVE TO WATCH THIS. WENT WITH A
DRY FORECAST TONIGHT AS MODEL SOUNDINGS SHOW CAPPING INVERSION AS
WARM AIR CONTINUES TO ADVECT IN AT MID LEVELS.
EXPECT THE CAPPING TO CONTINUE TUESDAY EVEN AS SFC LOW MOVES
ACROSS NORTHERN LOWER MICHIGAN. WENT WITH A DRY FORECAST UP NORTH
WITH THE EXPECTATION THAT RAINS WILL HOLD OFF UNTIL FRONT BEGINS
TO SAG SOUTH TUESDAY NIGHT. SHOWERS AND STORMS CONTINUE TO SPREAD
SLOWLY SOUTH THROUGH WEDNESDAY. THE FRONT SHOULD CLEAR SOUTHERN
ZONES WEDNESDAY EVENING WITH SHOWERS ENDING FROM NORTH TO SOUTH.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 334 PM EDT MON SEP 9 2013
MAIN ITEMS TO FOCUS ON IN THE LONG TERM ARE THE COOL AIR MASS THAT
WILL SETTLE IN ACROSS THE AREA AND THEN THE PCPN CHCS OVER THE
WEEKEND WITH THE NEXT SYSTEM EXPECTED TO MOVE IN ACROSS THE AREA. NO
REAL CHANGES WERE MADE TO THE FCST AS THE LATEST DATA CONTINUES TO
SUPPORT THE GOING FCST.
THE FCST LOOKS LIKE IT SHOULD REMAIN DRY FROM THE THU THROUGH SAT
TIME FRAME. THE MAIN FRONT MOVING THROUGH WED SHOULD BE WELL SOUTH
OF THE AREA BY THU MORNING. IT APPEARS WE WILL SEE A SECONDARY FRONT
MOVING THROUGH ON THU. MOISTURE IS QUITE LIMITED ON THU SO WE DO
NOT EXPECT PCPN WITH THE SECONDARY FRONT.
THE HEART OF THE COLD AIR ALOFT WILL MOVE IN BY FRI MORNING. H850
TEMPS ARE EXPECTED TO BOTTOM OUT AROUND 0 TO 2C. THIS HAS THE
POTENTIAL TO PRODUCE LAKE EFFECT...HOWEVER THE MEAN LOW LEVEL FLOW
WILL BE NNE. THIS SHOULD KEEP LAKE EFFECT WEST AND WELL EAST OF THE
CWFA FROM LAKES MICHIGAN AND HURON RESPECTIVELY. SOME FROST WILL BE
POSSIBLE UP NORTH IN THE NORMALLY COLDER LOCATIONS. TEMPS WILL THEN
MODERATE A BIT FOR SAT AS SHORT WAVE RIDGING ALOFT MOVES IN AND AS
RETURN FLOW BEGINS TO SET UP IN THE LOWER LEVELS.
THE NEXT CHANCE OF RAIN WILL COME IN LATE SAT NIGHT AND DURING THE
DAY ON SUN. A STRONG RIDGE WILL BUILD ACROSS THE ROCKIES BY SUN.
THIS WILL HELP TO DIG A FAIRLY GOOD SHORT WAVE SE INTO THE AREA. NOT
A LOT OF INSTABILITY SHOWN BY THE MODELS FOR STORMS. THERE IS JUST
ENOUGH COMBINED WITH A WELL DEFINED SHORT WAVE TO JUSTIFY THE
MENTION FOR NOW. THIS SHOULD CLEAR OUT BY MON...PROVIDING ANOTHER
COOL DOWN FOR THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1149 PM EDT MON SEP 9 2013
MOSTLY VFR CONDITIONS EXPECTED THROUGH THE NEXT 24 HOURS. SKIES
SHOULD ALSO REMAIN MAINLY CLEAR. ADDED LIGHT FOG/HAZE ACROSS THE
AREA... AS THE WINDS HAVE MOSTLY REMAINED UNDER 10 KNOTS OUT OF THE
SOUTH THUS FAR.
&&
.MARINE...
ISSUED AT 334 PM EDT MON SEP 9 2013
WINDS AND WAVES ARE COMING UP AND SCA CONDITIONS EXPECTED TO
PERSIST INTO TUESDAY AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 334 PM EDT MON SEP 9 2013
HEAVY RAIN POTENTIAL IS LOW UNTIL TUESDAY NIGHT WEDNESDAY WHEN A
COLD FRONT MOVES THROUGH.
&&
.CLIMATE...
ISSUED AT 334 PM EDT MON SEP 9 2013
MAX TEMPS ON TUESDAY COULD CHALLENGE RECORDS AT THE THREE PRIMARY
CLIMATE SITES...ESPECIALLY MUSKEGON WHERE THE RECORD IS ONLY 88.
RECORD AT GRAND RAPIDS IS 94 AND LANSING 93.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH TUESDAY AFTERNOON FOR
MIZ037-043-
050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EDT TUESDAY FOR LMZ844>849.
&&
$$
UPDATE...JK
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...NJJ
AVIATION...63
HYDROLOGY...OSTUNO
CLIMATE...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1023 PM EDT MON SEP 9 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 334 PM EDT MON SEP 9 2013
A WARM FRONT MOVED THROUGH WITH SOME HEAVY RAIN MONDAY MORNING.
THE RAIN IS GONE AND WARM AND HUMID WEATHER WILL BE AROUND UNTIL
TUESDAY NIGHT AND WEDNESDAY BEFORE A COLD FRONT USHERS IN SOME
VERY COOL TEMPERATURES FOR THE END OF THE WEEK.
&&
.UPDATE...
ISSUED AT 1023 PM EDT MON SEP 9 2013
UPDATED TO RAISE MIN TEMPS OVERNIGHT. WE CONTINUE TO WARM
ADVECT OVERNIGHT...WITH H9 TEMPS INCREASING TO AN AMAZING +28C
(83F)! FEEL SURFACE TEMPS WILL REMAIN FAIRLY STEADY AFTER 06Z...
MAINLY IN THE MID 70S...WITH A FEW LOW 70S FAR NORTH.
UPDATE ISSUED AT 619 PM EDT MON SEP 9 2013
WE HAVE ISSUED AN UPDATE TO ADD IN A FEW SHOWERS/ISOLATED STORMS
FOR THE NEXT COUPLE OF HOURS UP NORTH FOR OSCEOLA AND CLARE
COUNTIES. A FEW SHOWERS WERE OCCURRING NORTH OF THE CWFA NORTH OF
THE WARM FRONT AND INTERACTING WITH AN OLD REMNANT MCV COMING IN
FROM THE W/NW. IT APPEARS THESE SHOULD MOVE OUT IN THE NEXT COUPLE
OF HOURS...AND ALLOW FOR THE EXPECTED DRY NIGHT OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 334 PM EDT MON SEP 9 2013
FORECAST ISSUES IN THE NEAR TERM ARE POTENTIAL FOR SOME SHOWERS
THIS EVENING...MAX TEMPS ON TUESDAY AND TIMING PRECIP ALONG THE
FRONT TUESDAY NIGHT THROUGH WEDNESDAY.
AS FOR WHAT HAPPENED LAST NIGHT...THE STORMS CERTAINLY
OUTPERFORMED THE FORECAST QPF AS MID LEVEL INSTABILITY COMBINED
WITH STRONG MOISTURE ADVECTION AND ISENTROPIC LIFT NORTH OF THE
SFC WARM FRONT. IT APPEARS THE REMNANTS OF AN MCS HELPED FOCUS THE
CONVECTION AS WELL...WITH RADAR LOOPS SHOWING AN MCV CIRCULATION
MOVING SOUTHEAST ACROSS THE FORECAST AREA CONCURRENT WITH THE DEEP
CONVECTION.
AS FOR LATE THIS AFTERNOON AND EVENING...THE SFC WARM FRONT
WILL BE LIFTING NORTH ACROSS LOWER MICHIGAN AND THE HRRR IS SHOWING
SHOWERS BRUSHING THE NORTHERN FORECAST AREA AS AN MCS MOVES EAST
ACROSS THE UPPER PENINSULA. WILL HAVE TO WATCH THIS. WENT WITH A
DRY FORECAST TONIGHT AS MODEL SOUNDINGS SHOW CAPPING INVERSION AS
WARM AIR CONTINUES TO ADVECT IN AT MID LEVELS.
EXPECT THE CAPPING TO CONTINUE TUESDAY EVEN AS SFC LOW MOVES
ACROSS NORTHERN LOWER MICHIGAN. WENT WITH A DRY FORECAST UP NORTH
WITH THE EXPECTATION THAT RAINS WILL HOLD OFF UNTIL FRONT BEGINS
TO SAG SOUTH TUESDAY NIGHT. SHOWERS AND STORMS CONTINUE TO SPREAD
SLOWLY SOUTH THROUGH WEDNESDAY. THE FRONT SHOULD CLEAR SOUTHERN
ZONES WEDNESDAY EVENING WITH SHOWERS ENDING FROM NORTH TO SOUTH.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 334 PM EDT MON SEP 9 2013
MAIN ITEMS TO FOCUS ON IN THE LONG TERM ARE THE COOL AIR MASS THAT
WILL SETTLE IN ACROSS THE AREA AND THEN THE PCPN CHCS OVER THE
WEEKEND WITH THE NEXT SYSTEM EXPECTED TO MOVE IN ACROSS THE AREA. NO
REAL CHANGES WERE MADE TO THE FCST AS THE LATEST DATA CONTINUES TO
SUPPORT THE GOING FCST.
THE FCST LOOKS LIKE IT SHOULD REMAIN DRY FROM THE THU THROUGH SAT
TIME FRAME. THE MAIN FRONT MOVING THROUGH WED SHOULD BE WELL SOUTH
OF THE AREA BY THU MORNING. IT APPEARS WE WILL SEE A SECONDARY FRONT
MOVING THROUGH ON THU. MOISTURE IS QUITE LIMITED ON THU SO WE DO
NOT EXPECT PCPN WITH THE SECONDARY FRONT.
THE HEART OF THE COLD AIR ALOFT WILL MOVE IN BY FRI MORNING. H850
TEMPS ARE EXPECTED TO BOTTOM OUT AROUND 0 TO 2C. THIS HAS THE
POTENTIAL TO PRODUCE LAKE EFFECT...HOWEVER THE MEAN LOW LEVEL FLOW
WILL BE NNE. THIS SHOULD KEEP LAKE EFFECT WEST AND WELL EAST OF THE
CWFA FROM LAKES MICHIGAN AND HURON RESPECTIVELY. SOME FROST WILL BE
POSSIBLE UP NORTH IN THE NORMALLY COLDER LOCATIONS. TEMPS WILL THEN
MODERATE A BIT FOR SAT AS SHORT WAVE RIDGING ALOFT MOVES IN AND AS
RETURN FLOW BEGINS TO SET UP IN THE LOWER LEVELS.
THE NEXT CHANCE OF RAIN WILL COME IN LATE SAT NIGHT AND DURING THE
DAY ON SUN. A STRONG RIDGE WILL BUILD ACROSS THE ROCKIES BY SUN.
THIS WILL HELP TO DIG A FAIRLY GOOD SHORT WAVE SE INTO THE AREA. NOT
A LOT OF INSTABILITY SHOWN BY THE MODELS FOR STORMS. THERE IS JUST
ENOUGH COMBINED WITH A WELL DEFINED SHORT WAVE TO JUSTIFY THE
MENTION FOR NOW. THIS SHOULD CLEAR OUT BY MON...PROVIDING ANOTHER
COOL DOWN FOR THE AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 710 PM EDT MON SEP 9 2013
VFR CONDITIONS EXPECTED THROUGH THE NEXT 24 HOURS AND SKIES SHOULD
REMAIN MAINLY CLEAR. THE WIND IS EXPECTED TO BUILD TO AND REMAIN AT
10 KNOTS OR MORE INTO TUESDAY EVENING. THEREFORE... ANY POTENTIAL
FOG OVERNIGHT SHOULD BE LIMITED.
&&
.MARINE...
ISSUED AT 334 PM EDT MON SEP 9 2013
WINDS AND WAVES ARE COMING UP AND SCA CONDITIONS EXPECTED TO
PERSIST INTO TUESDAY AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 334 PM EDT MON SEP 9 2013
HEAVY RAIN POTENTIAL IS LOW UNTIL TUESDAY NIGHT WEDNESDAY WHEN A
COLD FRONT MOVES THROUGH.
&&
.CLIMATE...
ISSUED AT 334 PM EDT MON SEP 9 2013
MAX TEMPS ON TUESDAY COULD CHALLENGE RECORDS AT THE THREE PRIMARY
CLIMATE SITES...ESPECIALLY MUSKEGON WHERE THE RECORD IS ONLY 88.
RECORD AT GRAND RAPIDS IS 94 AND LANSING 93.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH TUESDAY AFTERNOON FOR MIZ037-043-
050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EDT TUESDAY FOR LMZ844>849.
&&
$$
UPDATE...JK
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...NJJ
AVIATION...63
HYDROLOGY...OSTUNO
CLIMATE...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
857 PM EDT MON SEP 9 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 419 PM EDT MON SEP 9 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A MID LEVEL LOW OVER NE
MT. LOW IS WEAKENING/OPENING UP ON WATER VAPOR LOOP/ANALYSIS AND IS
FCST TO MOVE E THROUGH THE NRN PLAINS STATES TONIGHT. ASSOC SFC LOW
NOW OVER SW MN IS IN TURN FCST TO LIFT NE ACROSS THE FCST AREA
TONIGHT WITH APPROACH OF NRN PLAINS SHORTWAVE. STRONG WAA/ISENTROPIC
LIFT AHEAD OF FRONTAL BOUNDARY AS IT LIFTS FM SRN WI TOWARD SCNTRL
UPR MI THIS EVENING WILL PROVIDE FOCUS FOR ANOTHER ROUND OF
CONVECTION TONIGHT WITH THE POTENTIAL FOR STRONG TO POSSIBLY SVR
STORMS.
TONIGHT...BIGGEST THING GOING AGAINST SVR WX TONIGHT WILL BE LACK OF
SFC-BASED INSTABILITY FM TODAY DUE TO THICK CLOUDS PERSISTING OVER
THE AREA FM EARLIER MCS OVER THE NRN PLAINS. EVEN SO...COMBINATION
OF STRENGTHING LOW-LVL JET...INCREASING WAA/ISENTROPIC LIFT AND
ADVANCE OF WARM FRONTAL BOUNDARY TOWARD SCNTRL FCST AREA WILL ALLOW
FOR INCREASING ELEVATED INSTABILITY (NAM AND RUC SHOW ELEVATED CAPES
IN EXCESS OF 2000 J/KG THIS EVENING) AND DEEP LAYER SHEAR TO 45-50
KT WHICH COULD BRING POTENTIAL FOR STRONG TO POSSIBLY SVR
STORMS...WITH THE BEST THREAT FOR SVR OVER SCNTRL MI AND SE UPR MI
IN CLOSER PROXIMITY TO ADVANCING WARM FRONT. GIVEN LACK OF SFC-BASED
INSTABILITY...THERE MAY BE MORE OF A THREAT OF ELEVATED STORMS WITH
LARGE HAIL PERHAPS BEING THE BIGGER THREAT FOR OUR AREA. WILL
CONTINUE TO MENTION STRONG TO SEVERE STORMS IN THE HWO WITH THE BEST
THREAT OF HEAVY RAINFALL ACROSS NRN UPR MI AND THE KEWEENAW
PENINSULA. MODEL QPF STILL SUGGESTS THE KEWEENAW PENINSULA AND ERN
UPR MI WILL HAVE BEST CHC FOR HEAVY RAINFALL TONIGHT. LOOK FOR A
GENERAL DIMINISHING TREND IN CONVECTION OVERNIGHT (AFT 06Z) AS
LOW-LVL JET VEERS FM SW TO A MORE WRLY DIRECTION.
DENSE FOG HAS BEEN OBSERVED OVER THE KEWEENAW PENINSULA AND LAKE
SUPERIOR THIS AFTERNOON AND WOULD EXPECT FOG TO CONTINUE INTO THIS
EVENING WITH SHRA MOVING OVER THE AREA AND ONSHORE E-SE FLOW
PERSISTING. EXPECT PATCHY FOG TO MOVE ONSHORE TO NRN ZONES LATE
TONIGHT AS WIND SHIFTS N-NW BEHIND SFC TROUGH.
TUESDAY...THERE COULD BE SOME LINGERING UPSLOPE DZ IN THE MORNING
OVER NRN ZONES AS LOW-LVLS REMAIN MOIST. SOME ISOLD SHRA ARE ALSO
POSSIBLE MAINLY OVER SCNTRL AND ERN SECTIONS OF THE CWA UNTIL
LINGERING SFC BOUNDARY SAGS SE OF THE AREA LATE IN THE DAY.
PERSISTENT CLOUDS OVER THE AREA WILL RESULT IN HIGH TEMPS RANGING
FROM THE 60S NEAR LAKE SUPERIOR IN ONSHORE FLOW TO THE MID 70S
SCNTRL AND EAST ALONG FRONTAL BOUNDARY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 419 PM EDT MON SEP 9 2013
A WEAK HIGH PRESSURE RIDGE WILL SLIDE OVER THE AREA ON TUESDAY
NIGHT BEHIND THE EXITING LOW PRESSURE SYSTEM. WITH THE AREA STILL
UNDER THE RIGHT REAR OF THE UPPER JET...A WEAK SHORTWAVE MOVING
THROUGH...AND SOME LINGERING MOISTURE...OPTED TO LINGER A FEW
ISOLATED SHOWERS NEAR LAKE MICHIGAN FOR THE FIRST PART OF THE
EVENING.
ATTENTION THEN TURNS TO THE SHORTWAVE THAT IS CURRENTLY IN THE
WESTERN PART OF THE NORTHWEST TERRITORIES. THIS SHORTWAVE WILL DIVE
SOUTHEAST TO LAKE WINNIPEG BY 12Z WEDNESDAY AND THEN THROUGH THE
UPPER GREAT LAKES WEDNESDAY NIGHT AND CONTINUE TO INFLUENCE THE
WEATHER INTO THURSDAY. A LOW PRESSURE SYSTEM ASSOCIATED WITH THIS
SHORTWAVE WILL TRACK ACROSS NORTHERN ONTARIO AND SWEEP THE MAIN COLD
FRONT ACROSS THE CWA LATE WEDNESDAY MORNING AND INTO THE AFTERNOON.
A WEAK TROUGH WILL TRY TO SLIDE ACROSS THE AREA LATE TUESDAY
NIGHT...WHICH COULD PRODUCE A FEW SHOWERS. BUT THE BEST CHANCE WILL
BE IN THE AFTERNOON WITH THE MAIN FRONT AND ASSISTANCE FROM DIURNAL
HEATING. THE MAIN INHIBITING FACTOR FOR MORE WIDESPREAD SHOWERS IS
THE SPLOTCHY NATURE OF THE DEEPER MOISTURE IN THE MODELS.
THUS...WILL GO FOR MORE LOW END CHANCES...WITH THE HIGHEST OVER THE
EAST BASED OFF THE TIMING OF THE FRONT WITH PEAK HEATING. DID CAP
THUNDER MENTION AT SLIGHT CHANCES...DUE TO THE WIDE VARIETY OF
MLCAPE VALUES IN THE MODELS (RANGING FROM 200-700 J/KG).
THURSDAY WILL BE COOL AND BREEZY ACROSS THE AREA WITH THE TIGHT
PRESSURE GRADIENT AS HIGH PRESSURE BUILDS INTO THE NORTHERN PLAINS.
850MB TEMPS WILL FALL FROM AROUND 11C ON WEDNESDAY TO 0-2C BY 00Z
THURSDAY. THE COOL TEMPERATURES OVER THE WARM LAKE WATERS WILL
COMBINE WITH THE LOW LEVEL MOISTURE SHOWN ON BOTH ECMWF/GFS FOR
LAKE INDUCED CLOUDS AND PROBABLY A FEW SHOWERS OVER THE LOCATIONS
FAVORED BY NORTH-NORTHWEST WINDS. EXPECT THE STRONGEST WIND GUSTS
TO BE OVER THE EASTERN CWA...WHERE WINDS WILL BE GUSTING TO
30MPH. WITH TEMPERATURES IN THE UPPER 50S AND LOWER 60S...THE
CLOUDS/WINDS/SHOWERS WILL LEAD TO A VERY OCTOBER LIKE DAY FOR MID
SEPTEMBER.
THE HIGH WILL BUILD SOUTHEAST ON THURSDAY NIGHT AND BE CENTERED
OVER THE AREA FOR FRIDAY AFTERNOON AND EVENING. THE DRY AIR
ASSOCIATED WITH THE HIGH WILL DIMINISH THE CLOUDS...BUT ALSO BRING
THE POTENTIAL FOR FROST OVER THE INTERIOR LOCATIONS THURSDAY NIGHT
AND FRIDAY NIGHT. CONFIDENCE IS FAIRLY LOW FOR THURSDAY NIGHT...AS
IT WILL DEPEND ON THE TIMING OF THE EXITING CLOUDS AND ALSO THE
WINDS WEAKENING UP FOR DECENT RADIATIONAL COOLING. THINK THE WESTERN
CWA WILL HAVE THE BEST CHANCE ON THURSDAY NIGHT AND WILL CONTINUE
THE COOLEST TEMPS THERE. THE CENTRAL AND EAST WILL HAVE THE BEST
SHOT FOR FROST ON FRIDAY NIGHT...SINCE THEY WILL BE THE CLOSEST TO
THE HIGH CENTER WITH THE LIGHTER WINDS. OVER THE FAR
WEST...SOUTHERLY RETURN FLOW ON THE BACK SIDE OF THE HIGH ON
FRIDAY NIGHT PRODUCES A LITTLE MORE UNCERTAINTY ON HOW COLD THE
TEMPS WILL GET BEFORE WINDS BEGIN TO PICK UP.
UPPER RIDGE WILL MOVE INTO THE AREA FOR SATURDAY AND BRING
TEMPERATURES BACK UP TOWARDS THE MID-UPPER 60S. THE NEXT SYSTEM
LOOKS TO AFFECT THE AREA ON SATURDAY NIGHT INTO SUNDAY. THIS
SHORTWAVE AND SURFACE LOW LOOK TO TAKE A SIMILAR TRACK TO THE ONE
THIS WEDNESDAY...ALTHOUGH THERE APPEARS TO BE A BETTER OPPORTUNITY
FOR RETURN FLOW TO PROVIDE MORE MOISTURE FOR SHOWERS AS THE FRONT
MOVES THROUGH. INSTABILITY AND MID-LEVEL LAPSE RATES ARE VERY
WEAK...SO HAVE LEFT THE MENTION OF THUNDER OUT OF THE FORECAST.
ONCE AGAIN...HIGH PRESSURE AND COOLER 850MB TEMPS WILL MOVE IN FOR
SUNDAY AFTERNOON INTO MONDAY...BRINGING ANOTHER BELOW NORMAL
TEMPERATURE DAY FOR MONDAY. GFS/ECMWF DO DIFFER ON THE AMOUNT OF
LOW LEVEL MOISTURE PRESENT FOR SUNDAY NIGHT INTO MONDAY...BUT WITH
THE COLD TEMPERATURES ALOFT IT SHOULDN/T TAKE MUCH TO KICK OF LAKE
CLOUDS OR EVEN SOME SHOWERS (AT LEAST FOR SUNDAY NIGHT).
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 857 PM EDT MON SEP 9 2013
WITH ABUNDANT LOW LEVEL MOISTURE OVER THE AREA LIFR OR VLIFR
CONDITIONS SHOULD PERSIST AT SAW/CMX OVERNIGHT INTO TUE MORNING.
SRLY WINDS AT IWD THAT ARE UNFAVORABLE FOR LOWER CIGS ARE EXPECTED
TO GIVE WAY TO IFR CIGS OVERNIGHT AS WINDS VEER NRLY. ONLY GRADUAL
IMPROVEMENT IS EXPECTED BY MIDDAY TUESDAY WITH DAYTIME MIXING AND
MODEST DRY ADVECTION WITH INCREASING WRLY FLOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EDT MON SEP 9 2013
LOW PRESSURE OVER NORTHEAST SD WILL LIFT INTO CENTRAL AND ERN UPR MI
TONIGHT AND THEN INTO FAR SE ONTARIO ON TUESDAY. NE WINDS FUNNELING
DOWN THE WRN PORTION OF LAKE SUPERIOR COULD GUST OVER 20 KT THIS
EVENING ON THE BACKSIDE OF THE LOW. A BRIEF RIDGE WILL MOVE OVER
LAKE SUPERIOR TUESDAY AFTERNOON THROUGH TUESDAY NIGHT...OUT AHEAD OF
A WEAK TROUGH EXTENDING FROM NORTHERN ONTARIO DURING THE DAY
WEDNESDAY. LARGE HIGH PRESSURE OVER SOUTH CENTRAL CANADA WEDNESDAY
NIGHT WILL SLOWLY SINK ACROSS GREAT LAKES...WHERE IT WILL REMAIN
FROM THURSDAY NIGHT THROUGH FRIDAY NIGHT. NW WINDS WILL LIKELY GUST
20-30KTS LATE WEDNESDAY NIGHT THROUGH LATE THURSDAY NIGHT AS HIGH
PRESSURE SINKS IN FROM THE NNW. OTHERWISE WITH HIGH PRESSURE
OVERHEAD...LIGHT WINDS LESS THAN 20KTS ARE EXPECTED BY FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
710 PM EDT MON SEP 9 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 334 PM EDT MON SEP 9 2013
A WARM FRONT MOVED THROUGH WITH SOME HEAVY RAIN MONDAY MORNING.
THE RAIN IS GONE AND WARM AND HUMID WEATHER WILL BE AROUND UNTIL
TUESDAY NIGHT AND WEDNESDAY BEFORE A COLD FRONT USHERS IN SOME
VERY COOL TEMPERATURES FOR THE END OF THE WEEK.
&&
.UPDATE...
ISSUED AT 619 PM EDT MON SEP 9 2013
WE HAVE ISSUED AN UPDATE TO ADD IN A FEW SHOWERS/ISOLATED STORMS
FOR THE NEXT COUPLE OF HOURS UP NORTH FOR OSCEOLA AND CLARE
COUNTIES. A FEW SHOWERS WERE OCCURRING NORTH OF THE CWFA NORTH OF
THE WARM FRONT AND INTERACTING WITH AN OLD REMNANT MCV COMING IN
FROM THE W/NW. IT APPEARS THESE SHOULD MOVE OUT IN THE NEXT COUPLE
OF HOURS...AND ALLOW FOR THE EXPECTED DRY NIGHT OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 334 PM EDT MON SEP 9 2013
FORECAST ISSUES IN THE NEAR TERM ARE POTENTIAL FOR SOME SHOWERS
THIS EVENING...MAX TEMPS ON TUESDAY AND TIMING PRECIP ALONG THE
FRONT TUESDAY NIGHT THROUGH WEDNESDAY.
AS FOR WHAT HAPPENED LAST NIGHT...THE STORMS CERTAINLY
OUTPERFORMED THE FORECAST QPF AS MID LEVEL INSTABILITY COMBINED
WITH STRONG MOISTURE ADVECTION AND ISENTROPIC LIFT NORTH OF THE
SFC WARM FRONT. IT APPEARS THE REMNANTS OF AN MCS HELPED FOCUS THE
CONVECTION AS WELL...WITH RADAR LOOPS SHOWING AN MCV CIRCULATION
MOVING SOUTHEAST ACROSS THE FORECAST AREA CONCURRENT WITH THE DEEP
CONVECTION.
AS FOR LATE THIS AFTERNOON AND EVENING...THE SFC WARM FRONT
WILL BE LIFTING NORTH ACROSS LOWER MICHIGAN AND THE HRRR IS SHOWING
SHOWERS BRUSHING THE NORTHERN FORECAST AREA AS AN MCS MOVES EAST
ACROSS THE UPPER PENINSULA. WILL HAVE TO WATCH THIS. WENT WITH A
DRY FORECAST TONIGHT AS MODEL SOUNDINGS SHOW CAPPING INVERSION AS
WARM AIR CONTINUES TO ADVECT IN AT MID LEVELS.
EXPECT THE CAPPING TO CONTINUE TUESDAY EVEN AS SFC LOW MOVES
ACROSS NORTHERN LOWER MICHIGAN. WENT WITH A DRY FORECAST UP NORTH
WITH THE EXPECTATION THAT RAINS WILL HOLD OFF UNTIL FRONT BEGINS
TO SAG SOUTH TUESDAY NIGHT. SHOWERS AND STORMS CONTINUE TO SPREAD
SLOWLY SOUTH THROUGH WEDNESDAY. THE FRONT SHOULD CLEAR SOUTHERN
ZONES WEDNESDAY EVENING WITH SHOWERS ENDING FROM NORTH TO SOUTH.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 334 PM EDT MON SEP 9 2013
MAIN ITEMS TO FOCUS ON IN THE LONG TERM ARE THE COOL AIR MASS THAT
WILL SETTLE IN ACROSS THE AREA AND THEN THE PCPN CHCS OVER THE
WEEKEND WITH THE NEXT SYSTEM EXPECTED TO MOVE IN ACROSS THE AREA. NO
REAL CHANGES WERE MADE TO THE FCST AS THE LATEST DATA CONTINUES TO
SUPPORT THE GOING FCST.
THE FCST LOOKS LIKE IT SHOULD REMAIN DRY FROM THE THU THROUGH SAT
TIME FRAME. THE MAIN FRONT MOVING THROUGH WED SHOULD BE WELL SOUTH
OF THE AREA BY THU MORNING. IT APPEARS WE WILL SEE A SECONDARY FRONT
MOVING THROUGH ON THU. MOISTURE IS QUITE LIMITED ON THU SO WE DO
NOT EXPECT PCPN WITH THE SECONDARY FRONT.
THE HEART OF THE COLD AIR ALOFT WILL MOVE IN BY FRI MORNING. H850
TEMPS ARE EXPECTED TO BOTTOM OUT AROUND 0 TO 2C. THIS HAS THE
POTENTIAL TO PRODUCE LAKE EFFECT...HOWEVER THE MEAN LOW LEVEL FLOW
WILL BE NNE. THIS SHOULD KEEP LAKE EFFECT WEST AND WELL EAST OF THE
CWFA FROM LAKES MICHIGAN AND HURON RESPECTIVELY. SOME FROST WILL BE
POSSIBLE UP NORTH IN THE NORMALLY COLDER LOCATIONS. TEMPS WILL THEN
MODERATE A BIT FOR SAT AS SHORT WAVE RIDGING ALOFT MOVES IN AND AS
RETURN FLOW BEGINS TO SET UP IN THE LOWER LEVELS.
THE NEXT CHANCE OF RAIN WILL COME IN LATE SAT NIGHT AND DURING THE
DAY ON SUN. A STRONG RIDGE WILL BUILD ACROSS THE ROCKIES BY SUN.
THIS WILL HELP TO DIG A FAIRLY GOOD SHORT WAVE SE INTO THE AREA. NOT
A LOT OF INSTABILITY SHOWN BY THE MODELS FOR STORMS. THERE IS JUST
ENOUGH COMBINED WITH A WELL DEFINED SHORT WAVE TO JUSTIFY THE
MENTION FOR NOW. THIS SHOULD CLEAR OUT BY MON...PROVIDING ANOTHER
COOL DOWN FOR THE AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 710 PM EDT MON SEP 9 2013
VFR CONDITIONS EXPECTED THROUGH THE NEXT 24 HOURS AND SKIES SHOULD
REMAIN MAINLY CLEAR. THE WIND IS EXPECTED TO BUILD TO AND REMAIN AT
10 KNOTS OR MORE INTO TUESDAY EVENING. THEREFORE... ANY POTENTIAL
FOG OVERNIGHT SHOULD BE LIMITED.
&&
.MARINE...
ISSUED AT 334 PM EDT MON SEP 9 2013
WINDS AND WAVES ARE COMING UP AND SCA CONDITIONS EXPECTED TO
PERSIST INTO TUESDAY AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 334 PM EDT MON SEP 9 2013
HEAVY RAIN POTENTIAL IS LOW UNTIL TUESDAY NIGHT WEDNESDAY WHEN A
COLD FRONT MOVES THROUGH.
&&
.CLIMATE...
ISSUED AT 334 PM EDT MON SEP 9 2013
MAX TEMPS ON TUESDAY COULD CHALLENGE RECORDS AT THE THREE PRIMARY
CLIMATE SITES...ESPECIALLY MUSKEGON WHERE THE RECORD IS ONLY 88.
RECORD AT GRAND RAPIDS IS 94 AND LANSING 93.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH TUESDAY AFTERNOON FOR
MIZ037-043-
050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EDT TUESDAY FOR LMZ844>849.
&&
$$
UPDATE...NJJ
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...NJJ
AVIATION...63
HYDROLOGY...OSTUNO
CLIMATE...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS GAYLORD MI
159 PM EDT SUN SEP 8 2013
.SYNOPSIS...
ISSUED AT 304 AM EDT SUN SEP 8 2013
HIGH PRESSURE PUSHING INTO THE STATE IS BRINGING WITH IT
SIGNIFICANTLY COOLER AND DRIER AIR TODAY. THE WARM AIR WILL
BEGIN TO RETURN MONDAY AS A WARM FRONT MOVES TOWARDS THE REGION.
THIS WILL BRING RENEWED CHANCES FOR SHOWERS AND THUNDERSTORMS.
WARM AND MUGGY CONDITIONS WILL PERSIST INTO TUESDAY BEFORE ANOTHER
COLD FRONT ARRIVES LATE TUESDAY. MUCH COOLER AIR WILL MOVE INTO
NORTHERN MICHIGAN TO END THE WEEK.
&&
.UPDATE...
ISSUED AT 105 PM EDT SUN SEP 8 2013
NO CHANGES TO THE FORECAST...STRATOCUMULUS THAT HAS FORMED THIS
MORNING HAS MIXED OUT AS EXPECTED...WITH JUST SOME HIGH CLOUDS
POURING INTO THE REGION FOR THIS AFTERNOON. TEMPERATURES LOOK TO
REMAIN ON TRACK...WITH LIGHTER EASTERLY FLOW COMPARED TO THIS
MORNING AS THE PRESSURE GRADIENT HAS SLACKENED AND HAS PUSHED TO
THE SOUTH.
UPDATE ISSUED AT 939 AM EDT SUN SEP 8 2013
CHANGES THIS HOUR: PRIMARY CHANGES WILL BE TO CLOUD COVER THROUGH
THE DAY...WITH RECENT OBSERVATIONS AND NEAR TERM RAP BUFR PROGS
SUGGESTING THAT WE/LL BUBBLE UP A BIT OF STCU BEFORE A GRADUAL
CLEARING TREND TAKES PLACE THIS AFTERNOON. OVERALL...THIS RESULTS
IN PRETTY MINOR CHANGES TO THE GOING FORECAST...WITH A PARTLY
SUNNY DAY EXPECTED FOR MOST. TEMPS LOOK ON TRACK TO REACH WITHIN A
FEW DEGREES OF THE 70F MARK.
UPDATE ISSUED AT 645 AM EDT SUN SEP 8 2013
STRONG HIGH PRESSURE...SUBSIDENCE AND DRY AIR THRU THE COLUMN
CONTINUES TO BUILD SOUTHWARD OUT OF ONTARIO AND INTO MICHIGAN
EARLY THIS MORNING. A FEW LOW CLOUDS REMAIN ACROSS FAR SRN
SECTIONS OF OUR CWA...BUT THOSE CLOUDS WILL SLIDE FURTHER SOUTH AS
DRIER AIR CONTINUES TO BUILD SOUTHWARD. ALSO...THE START OF
DAYTIME HEATING WILL LEND TO THE DISSIPATION OF RESIDUAL LOW
CLOUDS THRU DIURNAL MIXING ONCE THE SUN RISES. THE REST OF THE DAY
WILL BE SUNNY BUT NOT AS WARM AND HUMID AS YESTERDAY. HIGH TEMPS
THIS AFTERNOON WILL ONLY WARM INTO THE MID 60S TO LOWER 70S.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 304 AM EDT SUN SEP 8 2013
CURRENTLY, THE 500 MB RIDGE TO THE WEST LOOKS TO BE IN THE
BEGINNING STAGES OF FLATTENING AT THE LEAST AS THE WESTERN CUTOFF
LOW PUSHES INTO THE PAC NORTHWEST. TO THE EAST THE 500 MB TROUGH
LOOKS TO BE HOLDING IN PLACE. THIS SETS UP THE UPPER GREAT LAKES
FOR NORTHWEST FLOW/WARM ADVECTION PATTERN OVER THE NEXT COUPLE OF
DAYS. HOWEVER, IT THE VERY NEAR TERM (TODAY/TONIGHT), HIGH
PRESSURE WILL BE THE DOMINATE FEATURE.
TODAY...THE DRIER AIR, AS NOTED IN PREVIOUS UPDATES, IS MAKING ITS
WAY INTO THE N LOWER NOW, AS EVIDENT ON THE IR IMAGE. THE CLEARING
LINE HAS MADE IT TO ROUGHLY TO A LINE FROM APN TO FKS. THERE WAS A
CONCERN AT THE OUTSET OF THE EVENING FOR FOG, FROM THE RATHER
SOUPY AIR MASS THAT WAS LEFT FROM THE INITIAL SFC TROUGH. HOWEVER,
A SECOND, WEAKER TROUGH, USHERED IN THE DRIER, AND "BREEZIER"
AIR MASS. WITH THE WINDS OVER LAND, FROM THE TIGHTER GRADIENT,
HOLDING AROUND 5 TO 10 KNOTS, THIS HAS KEPT THE FOG FROM FORMING,
AND LEFT LOW CLOUDS BEHIND THE BOUNDARY. NOW THE DRY AIR AT 850 MB
AND BELOW IS PUSHING INTO THE REGION AND CLEARING THE FORECAST
AREA. BY DAYBREAK, IT LOOKS LIKE WE WILL GET MOSTLY SUNNY SKIES,
WITH ONLY THE CIRRUS BLOW OFF FROM THE MCS IN DAKOTAS, WHICH
SHOULD MOVE SOUTHEAST IN THE COMING HOURS, MISSING MICHIGAN.
TONIGHT...THE HIGH WILL TRANSIT THE FORECAST AREA DURING THE DAY,
SO THAT IN THE EVENING, THE RETURN FLOW WILL START IN NW LOWER.
TEMPERATURES THERE SHOULD IN THE 50S, WHILE IN NE LOWER AND E
UPPER THE WINDS WILL DECOUPLE FOR A TIME WHILE THE CORE OF THE
HIGH EXITS AND ALLOW SOME RADIATIONAL COOLING. TEMPERATURES WILL
FALL INTO THE UPPER 40S BEFORE HOLDING FROM THE RETURN FLOW AND
THE INCREASING CLOUDS FROM THE WARM FRONT BEGINNING TO FORM. THE
NAM AND GFS KEEP THE REGION DRY THROUGH 12Z AS THE BETTER
ISENTROPIC FORCING REMAINS UPSTREAM IN THE MINNESOTA ARROWHEAD.
THE ECMWF SEEMS THE OUTLIER WITH THE MOISTURE SOMEWHAT MORE
AGGRESSIVELY MOVING INTO LOWER MICHIGAN BY 12Z. CONSIDERING THAT
ALL THE MODELS HAVE THE SAME BASIC SCENARIO OF THE HIGH MOVING
TOWARD THE SE, AND THAT THE RETURN FLOW FROM A HIGH RETREATING IN
THAT DIRECTION USUALLY TAKES A LITTLE LONGER FOR THE RETURN FLOW
TO PUSH MOISTURE INTO THE STATE, THINK THAT THE GFS/NAM IDEA IS
RIGHT, SO HAVE THE RAIN STAYING OFF TO THE WEST THROUGH 12Z.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 304 AM EDT SUN SEP 8 2013
MONDAY THRU TUESDAY...SURFACE HIGH CENTER WILL SHIFT EAST OF OUR
STATE LATE SUNDAY NIGHT...WITH RETURN MOIST SOUTHERLY FLOW QUICKLY
KICKING IN EARLY MONDAY. A WARM FRONT ASSOCIATED WITH LOW PRESSURE
DEVELOPING IN THE NRN PLAINS WILL LIFT NE INTO NRN MICHIGAN ON
MONDAY. CHANCES OF SHOWERS AND STORMS WILL INCREASE...ESPECIALLY
ACROSS UPR AND FAR NRN LWR MICHIGAN AS DEEP MOISTURE POOLS AROUND
AND NORTH OF THE WARM FRONT. GREATEST CHANCE OF PRECIP WILL DEVELOP
MONDAY NIGHT AS THE SURFACE LOW CENTER TRACKS ALONG THE WARM FRONT
THRU THE STRAITS. THE ASSOCIATED COLD FRONT WILL SLOWLY SLIDE THRU
OUR CWA TUESDAY AND TUESDAY NIGHT. FOCUS OF CONVECTIVE DEVELOPMENT
WILL GENERALLY FOLLOW THIS BOUNDARY... GRADUALLY SHIFTING HIGHEST
POPS FROM ERN UPR AND FAR NRN LWR MICHIGAN ON TUESDAY SOUTHWARD TO
ALL OF NRN LWR MICHIGAN FOR TUESDAY NIGHT. TEMPS WILL RESPOND TO
STRENGTHENING WAA SOUTH OF THE WARM FRONT AND AHEAD OF THE COLD FRONT
BOTH MONDAY AND TUESDAY. HIGH TEMPS MONDAY AFTERNOON WILL WARM WELL
INTO THE 70S ACROSS NRN LWR MICHIGAN SOUTH OF THE WARM FRONT...AND
AROUND 70 ACROSS ERN UPR MICHIGAN WITHIN THICKER CLOUDS AND BETTER
PRECIP CHANCES ALONG THE WARM FRONT. HIGH TEMPS TUESDAY AFTERNOON
WILL VARY GREATLY ACROSS OUR CWA AS THE COOL FRONT SLIDES
THRU...RANGING FROM THE MID TO UPPER 70S IN ERN UPR MICHIGAN TO
AROUND 90 NEAR SAGINAW BAY.
WEDNESDAY THRU SATURDAY...BROAD DEEP CYCLONIC FLOW WILL LINGER ACROSS
THE WRN GREAT LAKES REGION IN THE WAKE OF THE COLD FRONT WEDNESDAY
INTO THURSDAY...AS WILL SOME LIMITED MOISTURE. LOW LEVEL CONVERGENCE
VIA THE CYCLONIC FLOW AND POCKETS OF MOISTURE WILL KEEP SMALL
CHANCES OF SHOWERS IN THE FORECAST THRU THURSDAY. CAA BEHIND THE
FRONT WILL DROP HIGH TEMPS BACK INTO THE 70S ON WEDNESDAY. A
STRONGER COLD FRONT WILL MOVE THRU THE WRN GREAT LAKES ON
THURSDAY...DROPPING TEMPS TO BELOW NORMAL LEVELS FOR THE LAST PART
OF THE WEEK. HIGH TEMPS ON THURSDAY WILL RANGE FROM THE MID 60S IN
ERN UPR MICHIGAN TO THE LOWER 70S IN OUR SE CWA. HIGH TEMPS ON
FRIDAY WILL STRUGGLE TO WARM OUT OF THE 50S ACROSS ERN UPR
MICHIGAN...AND WILL BE MAINLY IN THE LOWER 60S ACROSS NRN LWR
MICHIGAN. LATEST ECMWF IS TRENDING COLDER FOR FRIDAY...DROPPING 850
MB TEMPS TO -2 C ACROSS OUR FAR NRN CWA. COLD CANADIAN SURFACE HIGH
CENTER WILL MOVE OVERHEAD FRIDAY NIGHT/EARLY SATURDAY. THIS COLD
AIRMASS COMBINED WITH CLEARING SKIES AND LIGHT/CALM WINDS WILL
LIKELY RESULT IN SOME PATCHY FROST DEVELOPING LATE FRIDAY NIGHT INTO
EARLY SATURDAY. SATURDAY WILL BE ANOTHER COOL DAY...WITH HIGHS ONLY
IN THE 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 154 PM EDT SUN SEP 8 2013
VFR CONDITIONS WILL CONTINUE FOR ALL TAF SITES THROUGH THIS
AFTERNOON INTO TONIGHT...WITH HIGH PRESSURE IN CONTROL. WINDS WILL
REMAIN LIGHT OUT OF THE EAST TO NORTHEAST. FOG POTENTIAL TONIGHT
AT THIS POINT APPEARS LOW...AS WINDS WILL STRUGGLE TO DECOUPLE
DESPITE INCREASING MOISTURE OVER NORTHWEST LOWER. WILL LEAVE ANY
FOG MENTION OUT OF THE TAFS FOR NOW AND CONTINUE TO MONITOR TRENDS
THROUGH THE AFTERNOON.
&&
.MARINE...
ISSUED AT 304 AM EDT SUN SEP 8 2013
SMALL CRAFT WINDS ARE EXPECTED THROUGH THE MORNING AS THE GRADIENT
WON`T SLACKEN OVER THE LAKES UNTIL THE AFTERNOON. WINDS WILL
CONTINUE TO FALL OFF AS THE HIGH TAKES CONTROL THROUGH TONIGHT.
WINDS AND WAVES WILL INCREASE ON MONDAY AND MONDAY NIGHT AS THE
SFC LOW APPROACHES THE REGION.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LHZ348-
349.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...NS
SYNOPSIS...JL
SHORT TERM...JL
LONG TERM...MR
AVIATION...NS
MARINE...JL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
135 PM EDT SUN SEP 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT SUN SEP 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A RIDGE OVER NW CANADA AND
A TROF OVER ERN NAMERICA. STRONG SHORTWAVE DIVING SE TOWARD NEW
ENGLAND HAS RESULTED IN AMPLIFICATION OF THE ERN TROF OVER THE LAST
24HRS. UPSTREAM...MID LEVEL LOW THAT HAS BEEN OVER THE PACIFIC NW
OVER THE LAST FEW DAYS HAS MOVED LITTLE. CENTER IS CURRENTLY OVER
FAR NE WA. DOWNSTREAM OF THIS FEATURE...TAP OF SUBTROPICAL MOISTURE
EXTENDING INTO THE NRN ROCKIES HAS BEEN AIDING CLUSTERS OF SHRA/TSRA
ACROSS WY/MT INTO THE DAKOTAS. CLOSER TO HOME...IN THE WAKE OF THE
SHORTWAVE MOVING TOWARD NEW ENGLAND...SFC HIGH PRES HAS SETTLED OVER
NRN ONTARIO. FEED OF DRIER AIR ASSOCIATED WITH THE HIGH RESULTED IN
LOW CLOUDS/FOG ACROSS PORTIONS OF UPPER MI CLEARING OUT LAST
EVENING. EARLY THIS MORNING...ONLY SOME THIN CI BLOWOFF FROM
CONVECTION WELL TO THE W IS SPILLING INTO THE UPPER LAKES.
FCST AREA TODAY WILL BE UNDER THE INFLUENCE OF HIGH PRES MOVING SE
FROM NORTHERN ONTARIO. CU RULE SUGGESTS SCT CU SHOULD DEVELOP FOR A
TIME THIS MORNING/EARLY AFTN...SIMILAR TO WHAT WAS OBSERVED N/NW OF
LAKE SUPERIOR YESTERDAY. OTHERWISE...WILL PROBABLY CONTINUE TO SEE
SOME MAINLY THIN CI ACROSS THE FCST AREA TODAY. TEMPS WILL BE ON THE
COOL SIDE OF NORMAL DESPITE SUNSHINE. MIXING TO THE INVERSION BASE
ON FCST SOUNDINGS YIELDS HIGH TEMPS NEAR 70 AWAY FROM THE MODERATING
INFLUENCE OF THE GREAT LAKES. THIS LINES UP WELL WITH OBSERVED HIGHS
UPSTREAM YESTERDAY.
TONIGHT...MIDLEVEL LOW CURRENTLY OVER NE WA WILL BEGIN TO OPEN UP
AND DRIFT E INTO MT. WHILE THIS FEATURE WILL STILL BE TOO FAR W TO
BE A FACTOR HERE...MODELS SHOW WEAKER SHORTWAVES LIFTING NE AHEAD OF
THE LOW AND AROUND WEAKENING CNTRL CONUS RIDGE. AS IN RECENT DAYS...
FCST DILEMMA IS WHETHER ANY OF THESE WEAKER SHORTWAVES WILL BE ABLE
TO SPREAD PCPN INTO THE FCST AREA TONIGHT. THE ECMWF CONTINUES TO BE
MOST AGGRESSIVE SPREADING PCPN INTO THE UPPER LAKES. IN FACT...THE
00Z RUN IS MOST AGGRESSIVE AS IT SPREADS PCPN ACROSS THE ENTIRE FCST
AREA TONIGHT. MEANWHILE...OTHER MODELS WHICH HAD SUPPORTED A FASTER
EWD PUSH OF PCPN (UKMET IN PARTICULAR) HAVE BACKED OFF. GIVEN THE
RATHER SHARP ERN TROF...BELIEVE THE ECMWF IS PROBABLY TOO FAST
DRIVING PCPN EWD. 03Z SREF PROBABILITY OF AT LEAST 0.01 INCH OF PCPN
TONIGHT ONLY REACHES AROUND 20PCT OVER THE FAR W. SINCE BULK OF
GUIDANCE PAINTS A SIMILAR PICTURE TO THE SREF...WILL BASICALLY
MAINTAIN FCST CONTINUITY WITH THE LAST SEVERAL FCSTS AND ONLY BRING
SCHC POPS INTO THE W OVERNIGHT. OTHERWISE...SOUTHERLY RETURN FLOW OF
WARMER/MOISTER AIR AND AN INCREASE IN CLOUDS WILL RESULT IN A WARMER
NIGHT MOST AREAS...ESPECIALLY OVER THE W WHERE GRADIENT WILL BE
TIGHTENING FIRST AND WHERE THICKER CLOUDS WILL ARRIVE EARLIEST.
LINGERING DRY AIR MASS IN THE EVENING COMBINED WITH INITIALLY MOSTLY
CLEAR SKIES AND LIGHT WIND OVER THE E MAY ALLOW TEMPS AT TRADITIONAL
INTERIOR COLD SPOTS TO FALL INTO THE LWR 40S. ONE SIDE ISSUE THAT
MAY ARISE TONIGHT IS THE POTENTIAL FOR LOW CLOUDS AND/OR FOG OVER
THE E. IF SOUTHERLY WINDS UP LAKE MICHIGAN INCREASE SUFFICIENTLY...
LOW CLOUDS AND/OR FOG WILL DEVELOP AS HIGHER DWPT AIR OFF THE LAKE
ADVECTS INTO THE CHILLY INTERIOR. WILL BE SOMETHING TO WATCH FOR.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 535 AM EDT SUN SEP 8 2013
AT 12Z MONDAY UPPER MI WILL BE UNDER THE INFLUENCE OF THE 500MB
RIDGE...STRETCHING ACROSS MUCH OF THE S CENTRAL AND SE U.S. OUR EYES
WILL BE ON THE 500MB TROUGH OVER MT/ID/WY...WHICH WILL SUPPRESS THE
RIDGE TO OUR S AS THE TROUGH PUSHES TOWARD THE UPPER GREAT LAKES.
WARM FRONT WILL SURGE TO OUR N MONDAY MORNING...BEING THE FOCUS OF
SHRA/TSRA DURING THE DAY. THERE REMAINS SOME SIGNIFICANT
DISCREPANCIES ON THE TIMING WHEN COMPARING AVAILABLE MODELS. WHILE
THE NAM/GFS/CANADIAN MODELS KEEP BASICALLY ALL OF THE LAND
/EXCLUDING THE KEWEENAW PENINSULA/ DRY ON MONDAY...THE GENERALLY
FAVORED ECMWF HAS A SOLID 0.25IN OR MORE OVER THE ENTIRE LAND. HAVE
CONTINUED TO UTILIZE A MODEL CONSENSUS APPROACH...WHICH LEADS TO
AROUND 0.5 TO 1IN OF QPF FROM LATE TONIGHT THROUGH TUESDAY OVER THE
KEWEENAW PENINSULA...AND E AREAS N OF A LINE FROM MUNISING THROUGH
NEWBERRY. EXPECT MUCH OF THE STRONGER STORMS TO FOLLOW THE COLD
FRONT FARTHER TO OUR S...WITH LIGHTNING AND HEAVY RAIN BEING THE
MAIN THREATS FOR OUR CWA. AS FOR NON-PRECIP TALK...THE WAA WILL
RESULT IN A WARM NIGHT MONDAY NIGHT...APPROX 15F ABOVE NORMAL FOR
THIS TIME OF YEAR. THIS WILL BE THANKS TO WARM S WINDS REAMING UP
THROUGH THE NIGHT.
IT LOOKS TO BE A VERY ACTIVE AT 500MB FROM TUESDAY MORNING THROUGH
THE END OF THE WORK WEEK. THE INITIAL KICKER OF A SHORTWAVE WILL
PUSH W TO E ACROSS THE CWA TUESDAY AS THE SFC LOW EXITS E LAKE
SUPERIOR INTO SE QUEBEC. THIS WILL TIME OUT WITH THE RIGHT REAR
QUADRANT OF THE 250MB JET.
ALTHOUGH NOT A THREAT OF THUNDERSTORMS WILL BE DONE AFTER TUESDAY
AFTERNOON...THE EXTENDED SECTION OF THE FCST IS NOT WITHOUT
SIGNIFICANCE. LOOK FOR THE NEXT 500MB TROUGH TO SWING THROUGH MID
WEEK. WHILE NOT A SIGNIFICANT RAIN MAKER...IT WILL MARK THE START OF
SIGNIFICANTLY COOLER WEATHER. NW TO N WINDS WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT...WITH LINGERING LOW LEVEL MOISTURE. KEPT SLIGHT
CHANCE-CHANCE POPS NEAR LAKE SUPERIOR AS 850MB TEMPS FALL TO AROUND
-2C BY DAYBREAK FRIDAY. HIGHS IN THE 60S...AND EVEN UPPER 50S LOOK
REASONABLE FOR BOTH THURSDAY AND FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 134 PM EDT SUN SEP 8 2013
THE POCKET OF LOW CLOUDS SHOULD FINALLY BE EXITING KCMX AT TAF
ISSUANCE TIME. THE REST OF THE AFTERNOON SHOULD SEE VFR CONDITIONS
WITH HIGH PRESSURE OVERHEAD. HIGH CLOUDS WILL CONTINUE TO STREAM
OVER THE AREA AHEAD OF A LOW PRESSURE SYSTEM IN THE WESTERN PLAINS
STATES. THESE CLOUDS WILL THICKEN AND LOWER TONIGHT AS THE LOW MOVES
INTO THE EASTERN DAKOTAS.
WILL NEED TO WATCH FOR LOWER CLOUDS POSSIBLY MOVING NORTH INTO THE
CWA LATE TONIGHT INTO TOMORROW MORNING. THESE CLOUDS WOULD BE
ASSOCIATED WITH THE STRATUS NOW IN SOUTHWEST WISCONSIN. IF THE
PRECIPITATION NORTHWEST OF MINNEAPOLIS HOLDS TOGETHER AND DROPS
SOUTHEAST INTO NORTHERN/CENTRAL WISCONSIN...THIS WOULD EXPAND THE
ONGOING STRATUS. THEN...WITH 925MB FLOW INCREASING OUT OF THE
SOUTHERLY DIRECTION OVERNIGHT...IT WOULD SHIFT NORTH INTO THE AREA.
THIS IS ALSO AROUND THE TIME DECAYING SHOWERS WOULD BE NEARING FAR
WESTERN UPPER MICHIGAN. WILL ADD SCT WORDING FOR THE CLOUDS AT IWD
DUE TO LOWER CONFIDENCE LATE TONIGHT INTO TOMORROW MORNING AND
UNFAVORABLE SOUTH-SOUTHEAST FLOW. DID OPT FOR A MVFR CLOUD DECK AT
KSAW LATE IN THE MORNING WITH THE WINDS BEING FAVORABLE OUT OF THE
SOUTH-SOUTHEAST.
THE BEST OPPORTUNITY FOR SHOWERS WILL BE AT KCMX/KIWD...WHICH ARE
CLOSEST TO THE BETTER FORCING AS THE WARM FRONT LIFTS THROUGH THE
AREA TOMORROW. CONFIDENCE ON TIMING/LOCATION IS TOO LOW TO HAVE IT
BE THE PREDOMINANT CONDITIONS...SO HAVE JUST MENTIONED VCSH.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EDT SUN SEP 8 2013
HIGH PRES OVER NRN ONTARIO WILL DRIFT SE TODAY. JUST AHEAD OF THE
HIGH...EXPECT A BRIEF PUSH OF STRONGER WINDS (GUSTS TO 20-25KT) OVER
MUCH OF LAKE SUPERIOR EARLY THIS MORNING. COASTAL CONVERGENCE OVER
FAR WRN LAKE SUPERIOR AND PERHAPS BTWN THE HURON ISLANDS AND THE
KEWEENAW MAY STILL LEAD TO SOME GUSTS OVER 20KT LOCALLY THRU THE
AFTN. OTHERWISE...WINDS WILL SETTLE DOWN A BIT FOR THE AFTN...
ESPECIALLY OVER THE E...CLOSER TO SFC HIGH PRES CENTER. AS THE HIGH
MOVES AWAY FROM THE UPPER LAKES TONIGHT...GRADIENT SHOULD REMAIN
WEAK ENOUGH TO KEEP WINDS UNDER 20KT.
ANOTHER PERIOD OF STRONGER WINDS WILL BE POSSIBLE THURSDAY INTO
THURSDAY EVENING...WITH N-NW GUSTS OF 25-30KTS OVER MAINLY CENTRAL AND E
LAKE SUPERIOR...AS STRONG HIGH PRESSURE NEARS FROM S CENTRAL
CANADA AND LOW PRESSURE EXITS ACROSS QUEBEC.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...SRF
MARINE...KF
AREA FORECAST DISCUSSION
NWS GAYLORD MI
110 PM EDT SUN SEP 8 2013
.SYNOPSIS...
ISSUED AT 304 AM EDT SUN SEP 8 2013
HIGH PRESSURE PUSHING INTO THE STATE IS BRINGING WITH IT
SIGNIFICANTLY COOLER AND DRIER AIR TODAY. THE WARM AIR WILL
BEGIN TO RETURN MONDAY AS A WARM FRONT MOVES TOWARDS THE REGION.
THIS WILL BRING RENEWED CHANCES FOR SHOWERS AND THUNDERSTORMS.
WARM AND MUGGY CONDITIONS WILL PERSIST INTO TUESDAY BEFORE ANOTHER
COLD FRONT ARRIVES LATE TUESDAY. MUCH COOLER AIR WILL MOVE INTO
NORTHERN MICHIGAN TO END THE WEEK.
&&
.UPDATE...
ISSUED AT 105 PM EDT SUN SEP 8 2013
NO CHANGES TO THE FORECAST...STRATOCUMULUS THAT HAS FORMED THIS
MORNING HAS MIXED OUT AS EXPECTED...WITH JUST SOME HIGH CLOUDS
POURING INTO THE REGION FOR THIS AFTERNOON. TEMPERATURES LOOK TO
REMAIN ON TRACK...WITH LIGHTER EASTERLY FLOW COMPARED TO THIS
MORNING AS THE PRESSURE GRADIENT HAS SLACKENED AND HAS PUSHED TO
THE SOUTH.
UPDATE ISSUED AT 939 AM EDT SUN SEP 8 2013
CHANGES THIS HOUR: PRIMARY CHANGES WILL BE TO CLOUD COVER THROUGH
THE DAY...WITH RECENT OBSERVATIONS AND NEAR TERM RAP BUFR PROGS
SUGGESTING THAT WE/LL BUBBLE UP A BIT OF STCU BEFORE A GRADUAL
CLEARING TREND TAKES PLACE THIS AFTERNOON. OVERALL...THIS RESULTS
IN PRETTY MINOR CHANGES TO THE GOING FORECAST...WITH A PARTLY
SUNNY DAY EXPECTED FOR MOST. TEMPS LOOK ON TRACK TO REACH WITHIN A
FEW DEGREES OF THE 70F MARK.
UPDATE ISSUED AT 645 AM EDT SUN SEP 8 2013
STRONG HIGH PRESSURE...SUBSIDENCE AND DRY AIR THRU THE COLUMN
CONTINUES TO BUILD SOUTHWARD OUT OF ONTARIO AND INTO MICHIGAN
EARLY THIS MORNING. A FEW LOW CLOUDS REMAIN ACROSS FAR SRN
SECTIONS OF OUR CWA...BUT THOSE CLOUDS WILL SLIDE FURTHER SOUTH AS
DRIER AIR CONTINUES TO BUILD SOUTHWARD. ALSO...THE START OF
DAYTIME HEATING WILL LEND TO THE DISSIPATION OF RESIDUAL LOW
CLOUDS THRU DIURNAL MIXING ONCE THE SUN RISES. THE REST OF THE DAY
WILL BE SUNNY BUT NOT AS WARM AND HUMID AS YESTERDAY. HIGH TEMPS
THIS AFTERNOON WILL ONLY WARM INTO THE MID 60S TO LOWER 70S.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 304 AM EDT SUN SEP 8 2013
CURRENTLY, THE 500 MB RIDGE TO THE WEST LOOKS TO BE IN THE
BEGINNING STAGES OF FLATTENING AT THE LEAST AS THE WESTERN CUTOFF
LOW PUSHES INTO THE PAC NORTHWEST. TO THE EAST THE 500 MB TROUGH
LOOKS TO BE HOLDING IN PLACE. THIS SETS UP THE UPPER GREAT LAKES
FOR NORTHWEST FLOW/WARM ADVECTION PATTERN OVER THE NEXT COUPLE OF
DAYS. HOWEVER, IT THE VERY NEAR TERM (TODAY/TONIGHT), HIGH
PRESSURE WILL BE THE DOMINATE FEATURE.
TODAY...THE DRIER AIR, AS NOTED IN PREVIOUS UPDATES, IS MAKING ITS
WAY INTO THE N LOWER NOW, AS EVIDENT ON THE IR IMAGE. THE CLEARING
LINE HAS MADE IT TO ROUGHLY TO A LINE FROM APN TO FKS. THERE WAS A
CONCERN AT THE OUTSET OF THE EVENING FOR FOG, FROM THE RATHER
SOUPY AIR MASS THAT WAS LEFT FROM THE INITIAL SFC TROUGH. HOWEVER,
A SECOND, WEAKER TROUGH, USHERED IN THE DRIER, AND "BREEZIER"
AIR MASS. WITH THE WINDS OVER LAND, FROM THE TIGHTER GRADIENT,
HOLDING AROUND 5 TO 10 KNOTS, THIS HAS KEPT THE FOG FROM FORMING,
AND LEFT LOW CLOUDS BEHIND THE BOUNDARY. NOW THE DRY AIR AT 850 MB
AND BELOW IS PUSHING INTO THE REGION AND CLEARING THE FORECAST
AREA. BY DAYBREAK, IT LOOKS LIKE WE WILL GET MOSTLY SUNNY SKIES,
WITH ONLY THE CIRRUS BLOW OFF FROM THE MCS IN DAKOTAS, WHICH
SHOULD MOVE SOUTHEAST IN THE COMING HOURS, MISSING MICHIGAN.
TONIGHT...THE HIGH WILL TRANSIT THE FORECAST AREA DURING THE DAY,
SO THAT IN THE EVENING, THE RETURN FLOW WILL START IN NW LOWER.
TEMPERATURES THERE SHOULD IN THE 50S, WHILE IN NE LOWER AND E
UPPER THE WINDS WILL DECOUPLE FOR A TIME WHILE THE CORE OF THE
HIGH EXITS AND ALLOW SOME RADIATIONAL COOLING. TEMPERATURES WILL
FALL INTO THE UPPER 40S BEFORE HOLDING FROM THE RETURN FLOW AND
THE INCREASING CLOUDS FROM THE WARM FRONT BEGINNING TO FORM. THE
NAM AND GFS KEEP THE REGION DRY THROUGH 12Z AS THE BETTER
ISENTROPIC FORCING REMAINS UPSTREAM IN THE MINNESOTA ARROWHEAD.
THE ECMWF SEEMS THE OUTLIER WITH THE MOISTURE SOMEWHAT MORE
AGGRESSIVELY MOVING INTO LOWER MICHIGAN BY 12Z. CONSIDERING THAT
ALL THE MODELS HAVE THE SAME BASIC SCENARIO OF THE HIGH MOVING
TOWARD THE SE, AND THAT THE RETURN FLOW FROM A HIGH RETREATING IN
THAT DIRECTION USUALLY TAKES A LITTLE LONGER FOR THE RETURN FLOW
TO PUSH MOISTURE INTO THE STATE, THINK THAT THE GFS/NAM IDEA IS
RIGHT, SO HAVE THE RAIN STAYING OFF TO THE WEST THROUGH 12Z.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 304 AM EDT SUN SEP 8 2013
MONDAY THRU TUESDAY...SURFACE HIGH CENTER WILL SHIFT EAST OF OUR
STATE LATE SUNDAY NIGHT...WITH RETURN MOIST SOUTHERLY FLOW QUICKLY
KICKING IN EARLY MONDAY. A WARM FRONT ASSOCIATED WITH LOW PRESSURE
DEVELOPING IN THE NRN PLAINS WILL LIFT NE INTO NRN MICHIGAN ON
MONDAY. CHANCES OF SHOWERS AND STORMS WILL INCREASE...ESPECIALLY
ACROSS UPR AND FAR NRN LWR MICHIGAN AS DEEP MOISTURE POOLS AROUND
AND NORTH OF THE WARM FRONT. GREATEST CHANCE OF PRECIP WILL DEVELOP
MONDAY NIGHT AS THE SURFACE LOW CENTER TRACKS ALONG THE WARM FRONT
THRU THE STRAITS. THE ASSOCIATED COLD FRONT WILL SLOWLY SLIDE THRU
OUR CWA TUESDAY AND TUESDAY NIGHT. FOCUS OF CONVECTIVE DEVELOPMENT
WILL GENERALLY FOLLOW THIS BOUNDARY... GRADUALLY SHIFTING HIGHEST
POPS FROM ERN UPR AND FAR NRN LWR MICHIGAN ON TUESDAY SOUTHWARD TO
ALL OF NRN LWR MICHIGAN FOR TUESDAY NIGHT. TEMPS WILL RESPOND TO
STRENGTHENING WAA SOUTH OF THE WARM FRONT AND AHEAD OF THE COLD FRONT
BOTH MONDAY AND TUESDAY. HIGH TEMPS MONDAY AFTERNOON WILL WARM WELL
INTO THE 70S ACROSS NRN LWR MICHIGAN SOUTH OF THE WARM FRONT...AND
AROUND 70 ACROSS ERN UPR MICHIGAN WITHIN THICKER CLOUDS AND BETTER
PRECIP CHANCES ALONG THE WARM FRONT. HIGH TEMPS TUESDAY AFTERNOON
WILL VARY GREATLY ACROSS OUR CWA AS THE COOL FRONT SLIDES
THRU...RANGING FROM THE MID TO UPPER 70S IN ERN UPR MICHIGAN TO
AROUND 90 NEAR SAGINAW BAY.
WEDNESDAY THRU SATURDAY...BROAD DEEP CYCLONIC FLOW WILL LINGER ACROSS
THE WRN GREAT LAKES REGION IN THE WAKE OF THE COLD FRONT WEDNESDAY
INTO THURSDAY...AS WILL SOME LIMITED MOISTURE. LOW LEVEL CONVERGENCE
VIA THE CYCLONIC FLOW AND POCKETS OF MOISTURE WILL KEEP SMALL
CHANCES OF SHOWERS IN THE FORECAST THRU THURSDAY. CAA BEHIND THE
FRONT WILL DROP HIGH TEMPS BACK INTO THE 70S ON WEDNESDAY. A
STRONGER COLD FRONT WILL MOVE THRU THE WRN GREAT LAKES ON
THURSDAY...DROPPING TEMPS TO BELOW NORMAL LEVELS FOR THE LAST PART
OF THE WEEK. HIGH TEMPS ON THURSDAY WILL RANGE FROM THE MID 60S IN
ERN UPR MICHIGAN TO THE LOWER 70S IN OUR SE CWA. HIGH TEMPS ON
FRIDAY WILL STRUGGLE TO WARM OUT OF THE 50S ACROSS ERN UPR
MICHIGAN...AND WILL BE MAINLY IN THE LOWER 60S ACROSS NRN LWR
MICHIGAN. LATEST ECMWF IS TRENDING COLDER FOR FRIDAY...DROPPING 850
MB TEMPS TO -2 C ACROSS OUR FAR NRN CWA. COLD CANADIAN SURFACE HIGH
CENTER WILL MOVE OVERHEAD FRIDAY NIGHT/EARLY SATURDAY. THIS COLD
AIRMASS COMBINED WITH CLEARING SKIES AND LIGHT/CALM WINDS WILL
LIKELY RESULT IN SOME PATCHY FROST DEVELOPING LATE FRIDAY NIGHT INTO
EARLY SATURDAY. SATURDAY WILL BE ANOTHER COOL DAY...WITH HIGHS ONLY
IN THE 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 645 AM EDT SUN SEP 8 2013
OVERALL VFR CONDITIONS ARE EXPECTED ACROSS ALL NRN LWR MICHIGAN
TAF SITES THRU EARLY MORNING MORNING AS STRONG COOL CANADIAN HIGH
PRESSURE AND DRY AIR CONTINUE TO BUILD SOUTH INTO MICHIGAN. N/NE
WINDS AOB 10 KTS TODAY WILL BECOME LIGHT AND VARIABLE TONIGHT AS
THE SURFACE HIGH CENTER MOVES OVERHEAD.
&&
.MARINE...
ISSUED AT 304 AM EDT SUN SEP 8 2013
SMALL CRAFT WINDS ARE EXPECTED THROUGH THE MORNING AS THE GRADIENT
WON`T SLACKEN OVER THE LAKES UNTIL THE AFTERNOON. WINDS WILL
CONTINUE TO FALL OFF AS THE HIGH TAKES CONTROL THROUGH TONIGHT.
WINDS AND WAVES WILL INCREASE ON MONDAY AND MONDAY NIGHT AS THE
SFC LOW APPROACHES THE REGION.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LHZ348-
349.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...NS
SYNOPSIS...JL
SHORT TERM...JL
LONG TERM...MR
AVIATION...MR
MARINE...JL
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
942 AM EDT SUN SEP 8 2013
.SYNOPSIS...
ISSUED AT 304 AM EDT SUN SEP 8 2013
HIGH PRESSURE PUSHING INTO THE STATE IS BRINGING WITH IT
SIGNIFICANTLY COOLER AND DRIER AIR TODAY. THE WARM AIR WILL
BEGIN TO RETURN MONDAY AS A WARM FRONT MOVES TOWARDS THE REGION.
THIS WILL BRING RENEWED CHANCES FOR SHOWERS AND THUNDERSTORMS.
WARM AND MUGGY CONDITIONS WILL PERSIST INTO TUESDAY BEFORE ANOTHER
COLD FRONT ARRIVES LATE TUESDAY. MUCH COOLER AIR WILL MOVE INTO
NORTHERN MICHIGAN TO END THE WEEK.
&&
.UPDATE...
ISSUED AT 939 AM EDT SUN SEP 8 2013
CHANGES THIS HOUR: PRIMARY CHANGES WILL BE TO CLOUD COVER THROUGH
THE DAY...WITH RECENT OBSERVATIONS AND NEAR TERM RAP BUFR PROGS
SUGGESTING THAT WE/LL BUBBLE UP A BIT OF STCU BEFORE A GRADUAL
CLEARING TREND TAKES PLACE THIS AFTERNOON. OVERALL...THIS RESULTS
IN PRETTY MINOR CHANGES TO THE GOING FORECAST...WITH A PARTLY
SUNNY DAY EXPECTED FOR MOST. TEMPS LOOK ON TRACK TO REACH WITHIN A
FEW DEGREES OF THE 70F MARK.
UPDATE ISSUED AT 645 AM EDT SUN SEP 8 2013
STRONG HIGH PRESSURE...SUBSIDENCE AND DRY AIR THRU THE COLUMN
CONTINUES TO BUILD SOUTHWARD OUT OF ONTARIO AND INTO MICHIGAN
EARLY THIS MORNING. A FEW LOW CLOUDS REMAIN ACROSS FAR SRN
SECTIONS OF OUR CWA...BUT THOSE CLOUDS WILL SLIDE FURTHER SOUTH AS
DRIER AIR CONTINUES TO BUILD SOUTHWARD. ALSO...THE START OF
DAYTIME HEATING WILL LEND TO THE DISSIPATION OF RESIDUAL LOW
CLOUDS THRU DIURNAL MIXING ONCE THE SUN RISES. THE REST OF THE DAY
WILL BE SUNNY BUT NOT AS WARM AND HUMID AS YESTERDAY. HIGH TEMPS
THIS AFTERNOON WILL ONLY WARM INTO THE MID 60S TO LOWER 70S.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 304 AM EDT SUN SEP 8 2013
CURRENTLY, THE 500 MB RIDGE TO THE WEST LOOKS TO BE IN THE
BEGINNING STAGES OF FLATTENING AT THE LEAST AS THE WESTERN CUTOFF
LOW PUSHES INTO THE PAC NORTHWEST. TO THE EAST THE 500 MB TROUGH
LOOKS TO BE HOLDING IN PLACE. THIS SETS UP THE UPPER GREAT LAKES
FOR NORTHWEST FLOW/WARM ADVECTION PATTERN OVER THE NEXT COUPLE OF
DAYS. HOWEVER, IT THE VERY NEAR TERM (TODAY/TONIGHT), HIGH
PRESSURE WILL BE THE DOMINATE FEATURE.
TODAY...THE DRIER AIR, AS NOTED IN PREVIOUS UPDATES, IS MAKING ITS
WAY INTO THE N LOWER NOW, AS EVIDENT ON THE IR IMAGE. THE CLEARING
LINE HAS MADE IT TO ROUGHLY TO A LINE FROM APN TO FKS. THERE WAS A
CONCERN AT THE OUTSET OF THE EVENING FOR FOG, FROM THE RATHER
SOUPY AIR MASS THAT WAS LEFT FROM THE INITIAL SFC TROUGH. HOWEVER,
A SECOND, WEAKER TROUGH, USHERED IN THE DRIER, AND "BREEZIER"
AIR MASS. WITH THE WINDS OVER LAND, FROM THE TIGHTER GRADIENT,
HOLDING AROUND 5 TO 10 KNOTS, THIS HAS KEPT THE FOG FROM FORMING,
AND LEFT LOW CLOUDS BEHIND THE BOUNDARY. NOW THE DRY AIR AT 850 MB
AND BELOW IS PUSHING INTO THE REGION AND CLEARING THE FORECAST
AREA. BY DAYBREAK, IT LOOKS LIKE WE WILL GET MOSTLY SUNNY SKIES,
WITH ONLY THE CIRRUS BLOW OFF FROM THE MCS IN DAKOTAS, WHICH
SHOULD MOVE SOUTHEAST IN THE COMING HOURS, MISSING MICHIGAN.
TONIGHT...THE HIGH WILL TRANSIT THE FORECAST AREA DURING THE DAY,
SO THAT IN THE EVENING, THE RETURN FLOW WILL START IN NW LOWER.
TEMPERATURES THERE SHOULD IN THE 50S, WHILE IN NE LOWER AND E
UPPER THE WINDS WILL DECOUPLE FOR A TIME WHILE THE CORE OF THE
HIGH EXITS AND ALLOW SOME RADIATIONAL COOLING. TEMPERATURES WILL
FALL INTO THE UPPER 40S BEFORE HOLDING FROM THE RETURN FLOW AND
THE INCREASING CLOUDS FROM THE WARM FRONT BEGINNING TO FORM. THE
NAM AND GFS KEEP THE REGION DRY THROUGH 12Z AS THE BETTER
ISENTROPIC FORCING REMAINS UPSTREAM IN THE MINNESOTA ARROWHEAD.
THE ECMWF SEEMS THE OUTLIER WITH THE MOISTURE SOMEWHAT MORE
AGGRESSIVELY MOVING INTO LOWER MICHIGAN BY 12Z. CONSIDERING THAT
ALL THE MODELS HAVE THE SAME BASIC SCENARIO OF THE HIGH MOVING
TOWARD THE SE, AND THAT THE RETURN FLOW FROM A HIGH RETREATING IN
THAT DIRECTION USUALLY TAKES A LITTLE LONGER FOR THE RETURN FLOW
TO PUSH MOISTURE INTO THE STATE, THINK THAT THE GFS/NAM IDEA IS
RIGHT, SO HAVE THE RAIN STAYING OFF TO THE WEST THROUGH 12Z.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 304 AM EDT SUN SEP 8 2013
MONDAY THRU TUESDAY...SURFACE HIGH CENTER WILL SHIFT EAST OF OUR
STATE LATE SUNDAY NIGHT...WITH RETURN MOIST SOUTHERLY FLOW QUICKLY
KICKING IN EARLY MONDAY. A WARM FRONT ASSOCIATED WITH LOW PRESSURE
DEVELOPING IN THE NRN PLAINS WILL LIFT NE INTO NRN MICHIGAN ON
MONDAY. CHANCES OF SHOWERS AND STORMS WILL INCREASE...ESPECIALLY
ACROSS UPR AND FAR NRN LWR MICHIGAN AS DEEP MOISTURE POOLS AROUND
AND NORTH OF THE WARM FRONT. GREATEST CHANCE OF PRECIP WILL DEVELOP
MONDAY NIGHT AS THE SURFACE LOW CENTER TRACKS ALONG THE WARM FRONT
THRU THE STRAITS. THE ASSOCIATED COLD FRONT WILL SLOWLY SLIDE THRU
OUR CWA TUESDAY AND TUESDAY NIGHT. FOCUS OF CONVECTIVE DEVELOPMENT
WILL GENERALLY FOLLOW THIS BOUNDARY... GRADUALLY SHIFTING HIGHEST
POPS FROM ERN UPR AND FAR NRN LWR MICHIGAN ON TUESDAY SOUTHWARD TO
ALL OF NRN LWR MICHIGAN FOR TUESDAY NIGHT. TEMPS WILL RESPOND TO
STRENGTHENING WAA SOUTH OF THE WARM FRONT AND AHEAD OF THE COLD FRONT
BOTH MONDAY AND TUESDAY. HIGH TEMPS MONDAY AFTERNOON WILL WARM WELL
INTO THE 70S ACROSS NRN LWR MICHIGAN SOUTH OF THE WARM FRONT...AND
AROUND 70 ACROSS ERN UPR MICHIGAN WITHIN THICKER CLOUDS AND BETTER
PRECIP CHANCES ALONG THE WARM FRONT. HIGH TEMPS TUESDAY AFTERNOON
WILL VARY GREATLY ACROSS OUR CWA AS THE COOL FRONT SLIDES
THRU...RANGING FROM THE MID TO UPPER 70S IN ERN UPR MICHIGAN TO
AROUND 90 NEAR SAGINAW BAY.
WEDNESDAY THRU SATURDAY...BROAD DEEP CYCLONIC FLOW WILL LINGER ACROSS
THE WRN GREAT LAKES REGION IN THE WAKE OF THE COLD FRONT WEDNESDAY
INTO THURSDAY...AS WILL SOME LIMITED MOISTURE. LOW LEVEL CONVERGENCE
VIA THE CYCLONIC FLOW AND POCKETS OF MOISTURE WILL KEEP SMALL
CHANCES OF SHOWERS IN THE FORECAST THRU THURSDAY. CAA BEHIND THE
FRONT WILL DROP HIGH TEMPS BACK INTO THE 70S ON WEDNESDAY. A
STRONGER COLD FRONT WILL MOVE THRU THE WRN GREAT LAKES ON
THURSDAY...DROPPING TEMPS TO BELOW NORMAL LEVELS FOR THE LAST PART
OF THE WEEK. HIGH TEMPS ON THURSDAY WILL RANGE FROM THE MID 60S IN
ERN UPR MICHIGAN TO THE LOWER 70S IN OUR SE CWA. HIGH TEMPS ON
FRIDAY WILL STRUGGLE TO WARM OUT OF THE 50S ACROSS ERN UPR
MICHIGAN...AND WILL BE MAINLY IN THE LOWER 60S ACROSS NRN LWR
MICHIGAN. LATEST ECMWF IS TRENDING COLDER FOR FRIDAY...DROPPING 850
MB TEMPS TO -2 C ACROSS OUR FAR NRN CWA. COLD CANADIAN SURFACE HIGH
CENTER WILL MOVE OVERHEAD FRIDAY NIGHT/EARLY SATURDAY. THIS COLD
AIRMASS COMBINED WITH CLEARING SKIES AND LIGHT/CALM WINDS WILL
LIKELY RESULT IN SOME PATCHY FROST DEVELOPING LATE FRIDAY NIGHT INTO
EARLY SATURDAY. SATURDAY WILL BE ANOTHER COOL DAY...WITH HIGHS ONLY
IN THE 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 645 AM EDT SUN SEP 8 2013
OVERALL VFR CONDITIONS ARE EXPECTED ACROSS ALL NRN LWR MICHIGAN
TAF SITES THRU EARLY MORNING MORNING AS STRONG COOL CANADIAN HIGH
PRESSURE AND DRY AIR CONTINUE TO BUILD SOUTH INTO MICHIGAN. N/NE
WINDS AOB 10 KTS TODAY WILL BECOME LIGHT AND VARIABLE TONIGHT AS
THE SURFACE HIGH CENTER MOVES OVERHEAD.
&&
.MARINE...
ISSUED AT 304 AM EDT SUN SEP 8 2013
SMALL CRAFT WINDS ARE EXPECTED THROUGH THE MORNING AS THE GRADIENT
WON`T SLACKEN OVER THE LAKES UNTIL THE AFTERNOON. WINDS WILL
CONTINUE TO FALL OFF AS THE HIGH TAKES CONTROL THROUGH TONIGHT.
WINDS AND WAVES WILL INCREASE ON MONDAY AND MONDAY NIGHT AS THE
SFC LOW APPROACHES THE REGION.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LHZ348-
349.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR LMZ344>346.
LS...NONE.
&&
$$
UPDATE...ARNOTT
SYNOPSIS...JL
SHORT TERM...JL
LONG TERM...MR
AVIATION...MR
MARINE...JL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
741 AM EDT SUN SEP 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT SUN SEP 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A RIDGE OVER NW CANADA AND
A TROF OVER ERN NAMERICA. STRONG SHORTWAVE DIVING SE TOWARD NEW
ENGLAND HAS RESULTED IN AMPLIFICATION OF THE ERN TROF OVER THE LAST
24HRS. UPSTREAM...MID LEVEL LOW THAT HAS BEEN OVER THE PACIFIC NW
OVER THE LAST FEW DAYS HAS MOVED LITTLE. CENTER IS CURRENTLY OVER
FAR NE WA. DOWNSTREAM OF THIS FEATURE...TAP OF SUBTROPICAL MOISTURE
EXTENDING INTO THE NRN ROCKIES HAS BEEN AIDING CLUSTERS OF SHRA/TSRA
ACROSS WY/MT INTO THE DAKOTAS. CLOSER TO HOME...IN THE WAKE OF THE
SHORTWAVE MOVING TOWARD NEW ENGLAND...SFC HIGH PRES HAS SETTLED OVER
NRN ONTARIO. FEED OF DRIER AIR ASSOCIATED WITH THE HIGH RESULTED IN
LOW CLOUDS/FOG ACROSS PORTIONS OF UPPER MI CLEARING OUT LAST
EVENING. EARLY THIS MORNING...ONLY SOME THIN CI BLOWOFF FROM
CONVECTION WELL TO THE W IS SPILLING INTO THE UPPER LAKES.
FCST AREA TODAY WILL BE UNDER THE INFLUENCE OF HIGH PRES MOVING SE
FROM NORTHERN ONTARIO. CU RULE SUGGESTS SCT CU SHOULD DEVELOP FOR A
TIME THIS MORNING/EARLY AFTN...SIMILAR TO WHAT WAS OBSERVED N/NW OF
LAKE SUPERIOR YESTERDAY. OTHERWISE...WILL PROBABLY CONTINUE TO SEE
SOME MAINLY THIN CI ACROSS THE FCST AREA TODAY. TEMPS WILL BE ON THE
COOL SIDE OF NORMAL DESPITE SUNSHINE. MIXING TO THE INVERSION BASE
ON FCST SOUNDINGS YIELDS HIGH TEMPS NEAR 70 AWAY FROM THE MODERATING
INFLUENCE OF THE GREAT LAKES. THIS LINES UP WELL WITH OBSERVED HIGHS
UPSTREAM YESTERDAY.
TONIGHT...MIDLEVEL LOW CURRENTLY OVER NE WA WILL BEGIN TO OPEN UP
AND DRIFT E INTO MT. WHILE THIS FEATURE WILL STILL BE TOO FAR W TO
BE A FACTOR HERE...MODELS SHOW WEAKER SHORTWAVES LIFTING NE AHEAD OF
THE LOW AND AROUND WEAKENING CNTRL CONUS RIDGE. AS IN RECENT DAYS...
FCST DILEMMA IS WHETHER ANY OF THESE WEAKER SHORTWAVES WILL BE ABLE
TO SPREAD PCPN INTO THE FCST AREA TONIGHT. THE ECMWF CONTINUES TO BE
MOST AGGRESSIVE SPREADING PCPN INTO THE UPPER LAKES. IN FACT...THE
00Z RUN IS MOST AGGRESSIVE AS IT SPREADS PCPN ACROSS THE ENTIRE FCST
AREA TONIGHT. MEANWHILE...OTHER MODELS WHICH HAD SUPPORTED A FASTER
EWD PUSH OF PCPN (UKMET IN PARTICULAR) HAVE BACKED OFF. GIVEN THE
RATHER SHARP ERN TROF...BELIEVE THE ECMWF IS PROBABLY TOO FAST
DRIVING PCPN EWD. 03Z SREF PROBABILITY OF AT LEAST 0.01 INCH OF PCPN
TONIGHT ONLY REACHES AROUND 20PCT OVER THE FAR W. SINCE BULK OF
GUIDANCE PAINTS A SIMILAR PICTURE TO THE SREF...WILL BASICALLY
MAINTAIN FCST CONTINUITY WITH THE LAST SEVERAL FCSTS AND ONLY BRING
SCHC POPS INTO THE W OVERNIGHT. OTHERWISE...SOUTHERLY RETURN FLOW OF
WARMER/MOISTER AIR AND AN INCREASE IN CLOUDS WILL RESULT IN A WARMER
NIGHT MOST AREAS...ESPECIALLY OVER THE W WHERE GRADIENT WILL BE
TIGHTENING FIRST AND WHERE THICKER CLOUDS WILL ARRIVE EARLIEST.
LINGERING DRY AIR MASS IN THE EVENING COMBINED WITH INITIALLY MOSTLY
CLEAR SKIES AND LIGHT WIND OVER THE E MAY ALLOW TEMPS AT TRADITIONAL
INTERIOR COLD SPOTS TO FALL INTO THE LWR 40S. ONE SIDE ISSUE THAT
MAY ARISE TONIGHT IS THE POTENTIAL FOR LOW CLOUDS AND/OR FOG OVER
THE E. IF SOUTHERLY WINDS UP LAKE MICHIGAN INCREASE SUFFICIENTLY...
LOW CLOUDS AND/OR FOG WILL DEVELOP AS HIGHER DWPT AIR OFF THE LAKE
ADVECTS INTO THE CHILLY INTERIOR. WILL BE SOMETHING TO WATCH FOR.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 535 AM EDT SUN SEP 8 2013
AT 12Z MONDAY UPPER MI WILL BE UNDER THE INFLUENCE OF THE 500MB
RIDGE...STRETCHING ACROSS MUCH OF THE S CENTRAL AND SE U.S. OUR EYES
WILL BE ON THE 500MB TROUGH OVER MT/ID/WY...WHICH WILL SUPPRESS THE
RIDGE TO OUR S AS THE TROUGH PUSHES TOWARD THE UPPER GREAT LAKES.
WARM FRONT WILL SURGE TO OUR N MONDAY MORNING...BEING THE FOCUS OF
SHRA/TSRA DURING THE DAY. THERE REMAINS SOME SIGNIFICANT
DISCREPANCIES ON THE TIMING WHEN COMPARING AVAILABLE MODELS. WHILE
THE NAM/GFS/CANADIAN MODELS KEEP BASICALLY ALL OF THE LAND
/EXCLUDING THE KEWEENAW PENINSULA/ DRY ON MONDAY...THE GENERALLY
FAVORED ECMWF HAS A SOLID 0.25IN OR MORE OVER THE ENTIRE LAND. HAVE
CONTINUED TO UTILIZE A MODEL CONSENSUS APPROACH...WHICH LEADS TO
AROUND 0.5 TO 1IN OF QPF FROM LATE TONIGHT THROUGH TUESDAY OVER THE
KEWEENAW PENINSULA...AND E AREAS N OF A LINE FROM MUNISING THROUGH
NEWBERRY. EXPECT MUCH OF THE STRONGER STORMS TO FOLLOW THE COLD
FRONT FARTHER TO OUR S...WITH LIGHTNING AND HEAVY RAIN BEING THE
MAIN THREATS FOR OUR CWA. AS FOR NON-PRECIP TALK...THE WAA WILL
RESULT IN A WARM NIGHT MONDAY NIGHT...APPROX 15F ABOVE NORMAL FOR
THIS TIME OF YEAR. THIS WILL BE THANKS TO WARM S WINDS REAMING UP
THROUGH THE NIGHT.
IT LOOKS TO BE A VERY ACTIVE AT 500MB FROM TUESDAY MORNING THROUGH
THE END OF THE WORK WEEK. THE INITIAL KICKER OF A SHORTWAVE WILL
PUSH W TO E ACROSS THE CWA TUESDAY AS THE SFC LOW EXITS E LAKE
SUPERIOR INTO SE QUEBEC. THIS WILL TIME OUT WITH THE RIGHT REAR
QUADRANT OF THE 250MB JET.
ALTHOUGH NOT A THREAT OF THUNDERSTORMS WILL BE DONE AFTER TUESDAY
AFTERNOON...THE EXTENDED SECTION OF THE FCST IS NOT WITHOUT
SIGNIFICANCE. LOOK FOR THE NEXT 500MB TROUGH TO SWING THROUGH MID
WEEK. WHILE NOT A SIGNIFICANT RAIN MAKER...IT WILL MARK THE START OF
SIGNIFICANTLY COOLER WEATHER. NW TO N WINDS WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT...WITH LINGERING LOW LEVEL MOISTURE. KEPT SLIGHT
CHANCE-CHANCE POPS NEAR LAKE SUPERIOR AS 850MB TEMPS FALL TO AROUND
-2C BY DAYBREAK FRIDAY. HIGHS IN THE 60S...AND EVEN UPPER 50S LOOK
REASONABLE FOR BOTH THURSDAY AND FRIDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 740 AM EDT SUN SEP 8 2013
WITH ONE EXCEPTION...HIGH PRES MOVING SE THRU THE UPPER GREAT LAKES
WILL PROVIDE VFR CONDITIONS AT KIWD/KCMX/KSAW THRU THIS FCST PERIOD.
THAT ONE EXCEPTION IS THE POSSIBILITY OF A LOW MVFR OR IFR/LIFR
CLOUD DECK AT KCMX/KSAW FOR A COUPLE OF HRS THIS MORNING AS WINDS
ARE CURRENTLY VEERING AROUND MORE EASTERLY ACROSS LAKE SUPERIOR.
THIS IS RESULTING IN SLIGHTLY HIGHER DWPT MARINE LAYER AIR UPSLOPING
OFF THE LAKE INTO COOLER AIR INLAND. ONLY OTHER CONCERN FOR THIS
FCST PERIOD IS THE POSSIBILITY OF MARGINAL LLWS TONIGHT AT KIWD AND
POSSIBLY KCMX AS WINDS INCREASE ABOVE NOCTURNAL INVERSION IN
RESPONSE TO GRADIENT TIGHTENING BTWN DEPARTING SFC HIGH PRES AND LOW
PRES OVER THE WRN PLAINS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EDT SUN SEP 8 2013
HIGH PRES OVER NRN ONTARIO WILL DRIFT SE TODAY. JUST AHEAD OF THE
HIGH...EXPECT A BRIEF PUSH OF STRONGER WINDS (GUSTS TO 20-25KT) OVER
MUCH OF LAKE SUPERIOR EARLY THIS MORNING. COASTAL CONVERGENCE OVER
FAR WRN LAKE SUPERIOR AND PERHAPS BTWN THE HURON ISLANDS AND THE
KEWEENAW MAY STILL LEAD TO SOME GUSTS OVER 20KT LOCALLY THRU THE
AFTN. OTHERWISE...WINDS WILL SETTLE DOWN A BIT FOR THE AFTN...
ESPECIALLY OVER THE E...CLOSER TO SFC HIGH PRES CENTER. AS THE HIGH
MOVES AWAY FROM THE UPPER LAKES TONIGHT...GRADIENT SHOULD REMAIN
WEAK ENOUGH TO KEEP WINDS UNDER 20KT.
ANOTHER PERIOD OF STRONGER WINDS WILL BE POSSIBLE THURSDAY INTO
THURSDAY EVENING...WITH N-NW GUSTS OF 25-30KTS OVER MAINLY CENTRAL AND E
LAKE SUPERIOR...AS STRONG HIGH PRESSURE NEARS FROM S CENTRAL
CANADA AND LOW PRESSURE EXITS ACROSS QUEBEC.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
535 AM EDT SUN SEP 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT SUN SEP 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A RIDGE OVER NW CANADA AND
A TROF OVER ERN NAMERICA. STRONG SHORTWAVE DIVING SE TOWARD NEW
ENGLAND HAS RESULTED IN AMPLIFICATION OF THE ERN TROF OVER THE LAST
24HRS. UPSTREAM...MID LEVEL LOW THAT HAS BEEN OVER THE PACIFIC NW
OVER THE LAST FEW DAYS HAS MOVED LITTLE. CENTER IS CURRENTLY OVER
FAR NE WA. DOWNSTREAM OF THIS FEATURE...TAP OF SUBTROPICAL MOISTURE
EXTENDING INTO THE NRN ROCKIES HAS BEEN AIDING CLUSTERS OF SHRA/TSRA
ACROSS WY/MT INTO THE DAKOTAS. CLOSER TO HOME...IN THE WAKE OF THE
SHORTWAVE MOVING TOWARD NEW ENGLAND...SFC HIGH PRES HAS SETTLED OVER
NRN ONTARIO. FEED OF DRIER AIR ASSOCIATED WITH THE HIGH RESULTED IN
LOW CLOUDS/FOG ACROSS PORTIONS OF UPPER MI CLEARING OUT LAST
EVENING. EARLY THIS MORNING...ONLY SOME THIN CI BLOWOFF FROM
CONVECTION WELL TO THE W IS SPILLING INTO THE UPPER LAKES.
FCST AREA TODAY WILL BE UNDER THE INFLUENCE OF HIGH PRES MOVING SE
FROM NORTHERN ONTARIO. CU RULE SUGGESTS SCT CU SHOULD DEVELOP FOR A
TIME THIS MORNING/EARLY AFTN...SIMILAR TO WHAT WAS OBSERVED N/NW OF
LAKE SUPERIOR YESTERDAY. OTHERWISE...WILL PROBABLY CONTINUE TO SEE
SOME MAINLY THIN CI ACROSS THE FCST AREA TODAY. TEMPS WILL BE ON THE
COOL SIDE OF NORMAL DESPITE SUNSHINE. MIXING TO THE INVERSION BASE
ON FCST SOUNDINGS YIELDS HIGH TEMPS NEAR 70 AWAY FROM THE MODERATING
INFLUENCE OF THE GREAT LAKES. THIS LINES UP WELL WITH OBSERVED HIGHS
UPSTREAM YESTERDAY.
TONIGHT...MIDLEVEL LOW CURRENTLY OVER NE WA WILL BEGIN TO OPEN UP
AND DRIFT E INTO MT. WHILE THIS FEATURE WILL STILL BE TOO FAR W TO
BE A FACTOR HERE...MODELS SHOW WEAKER SHORTWAVES LIFTING NE AHEAD OF
THE LOW AND AROUND WEAKENING CNTRL CONUS RIDGE. AS IN RECENT DAYS...
FCST DILEMMA IS WHETHER ANY OF THESE WEAKER SHORTWAVES WILL BE ABLE
TO SPREAD PCPN INTO THE FCST AREA TONIGHT. THE ECMWF CONTINUES TO BE
MOST AGGRESSIVE SPREADING PCPN INTO THE UPPER LAKES. IN FACT...THE
00Z RUN IS MOST AGGRESSIVE AS IT SPREADS PCPN ACROSS THE ENTIRE FCST
AREA TONIGHT. MEANWHILE...OTHER MODELS WHICH HAD SUPPORTED A FASTER
EWD PUSH OF PCPN (UKMET IN PARTICULAR) HAVE BACKED OFF. GIVEN THE
RATHER SHARP ERN TROF...BELIEVE THE ECMWF IS PROBABLY TOO FAST
DRIVING PCPN EWD. 03Z SREF PROBABILITY OF AT LEAST 0.01 INCH OF PCPN
TONIGHT ONLY REACHES AROUND 20PCT OVER THE FAR W. SINCE BULK OF
GUIDANCE PAINTS A SIMILAR PICTURE TO THE SREF...WILL BASICALLY
MAINTAIN FCST CONTINUITY WITH THE LAST SEVERAL FCSTS AND ONLY BRING
SCHC POPS INTO THE W OVERNIGHT. OTHERWISE...SOUTHERLY RETURN FLOW OF
WARMER/MOISTER AIR AND AN INCREASE IN CLOUDS WILL RESULT IN A WARMER
NIGHT MOST AREAS...ESPECIALLY OVER THE W WHERE GRADIENT WILL BE
TIGHTENING FIRST AND WHERE THICKER CLOUDS WILL ARRIVE EARLIEST.
LINGERING DRY AIR MASS IN THE EVENING COMBINED WITH INITIALLY MOSTLY
CLEAR SKIES AND LIGHT WIND OVER THE E MAY ALLOW TEMPS AT TRADITIONAL
INTERIOR COLD SPOTS TO FALL INTO THE LWR 40S. ONE SIDE ISSUE THAT
MAY ARISE TONIGHT IS THE POTENTIAL FOR LOW CLOUDS AND/OR FOG OVER
THE E. IF SOUTHERLY WINDS UP LAKE MICHIGAN INCREASE SUFFICIENTLY...
LOW CLOUDS AND/OR FOG WILL DEVELOP AS HIGHER DWPT AIR OFF THE LAKE
ADVECTS INTO THE CHILLY INTERIOR. WILL BE SOMETHING TO WATCH FOR.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 535 AM EDT SUN SEP 8 2013
AT 12Z MONDAY UPPER MI WILL BE UNDER THE INFLUENCE OF THE 500MB
RIDGE...STRETCHING ACROSS MUCH OF THE S CENTRAL AND SE U.S. OUR EYES
WILL BE ON THE 500MB TROUGH OVER MT/ID/WY...WHICH WILL SUPPRESS THE
RIDGE TO OUR S AS THE TROUGH PUSHES TOWARD THE UPPER GREAT LAKES.
WARM FRONT WILL SURGE TO OUR N MONDAY MORNING...BEING THE FOCUS OF
SHRA/TSRA DURING THE DAY. THERE REMAINS SOME SIGNIFICANT
DISCREPANCIES ON THE TIMING WHEN COMPARING AVAILABLE MODELS. WHILE
THE NAM/GFS/CANADIAN MODELS KEEP BASICALLY ALL OF THE LAND
/EXCLUDING THE KEWEENAW PENINSULA/ DRY ON MONDAY...THE GENERALLY
FAVORED ECMWF HAS A SOLID 0.25IN OR MORE OVER THE ENTIRE LAND. HAVE
CONTINUED TO UTILIZE A MODEL CONSENSUS APPROACH...WHICH LEADS TO
AROUND 0.5 TO 1IN OF QPF FROM LATE TONIGHT THROUGH TUESDAY OVER THE
KEWEENAW PENINSULA...AND E AREAS N OF A LINE FROM MUNISING THROUGH
NEWBERRY. EXPECT MUCH OF THE STRONGER STORMS TO FOLLOW THE COLD
FRONT FARTHER TO OUR S...WITH LIGHTNING AND HEAVY RAIN BEING THE
MAIN THREATS FOR OUR CWA. AS FOR NON-PRECIP TALK...THE WAA WILL
RESULT IN A WARM NIGHT MONDAY NIGHT...APPROX 15F ABOVE NORMAL FOR
THIS TIME OF YEAR. THIS WILL BE THANKS TO WARM S WINDS REAMING UP
THROUGH THE NIGHT.
IT LOOKS TO BE A VERY ACTIVE AT 500MB FROM TUESDAY MORNING THROUGH
THE END OF THE WORK WEEK. THE INITIAL KICKER OF A SHORTWAVE WILL
PUSH W TO E ACROSS THE CWA TUESDAY AS THE SFC LOW EXITS E LAKE
SUPERIOR INTO SE QUEBEC. THIS WILL TIME OUT WITH THE RIGHT REAR
QUADRANT OF THE 250MB JET.
ALTHOUGH NOT A THREAT OF THUNDERSTORMS WILL BE DONE AFTER TUESDAY
AFTERNOON...THE EXTENDED SECTION OF THE FCST IS NOT WITHOUT
SIGNIFICANCE. LOOK FOR THE NEXT 500MB TROUGH TO SWING THROUGH MID
WEEK. WHILE NOT A SIGNIFICANT RAIN MAKER...IT WILL MARK THE START OF
SIGNIFICANTLY COOLER WEATHER. NW TO N WINDS WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT...WITH LINGERING LOW LEVEL MOISTURE. KEPT SLIGHT
CHANCE-CHANCE POPS NEAR LAKE SUPERIOR AS 850MB TEMPS FALL TO AROUND
-2C BY DAYBREAK FRIDAY. HIGHS IN THE 60S...AND EVEN UPPER 50S LOOK
REASONABLE FOR BOTH THURSDAY AND FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 136 AM EDT SUN SEP 8 2013
WITH HIGH PRESSURE BUILDING INTO THE REGION...VFR CONDITIONS WILL
CONTINUE TO PREVAIL AT KIWD/KCMX/KSAW THROUGH THE FORECAST PERIOD
WITH LIGHT EASTERLY WINDS. HOWEVER...THERE MAY BE BRIEF VIS
FLUCTUATIONS OVERNIGHT AT KIWD DUE TO PATCHES OF SHALLOW RADIATIONAL
FOG. WITH SOME CI SPREADING ACROSS THE AREA...DO NOT THINK THE FOG
WILL DEEPEN AND BECOME A PREVAILING CONDITION.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EDT SUN SEP 8 2013
HIGH PRES OVER NRN ONTARIO WILL DRIFT SE TODAY. JUST AHEAD OF THE
HIGH...EXPECT A BRIEF PUSH OF STRONGER WINDS (GUSTS TO 20-25KT) OVER
MUCH OF LAKE SUPERIOR EARLY THIS MORNING. COASTAL CONVERGENCE OVER
FAR WRN LAKE SUPERIOR AND PERHAPS BTWN THE HURON ISLANDS AND THE
KEWEENAW MAY STILL LEAD TO SOME GUSTS OVER 20KT LOCALLY THRU THE
AFTN. OTHERWISE...WINDS WILL SETTLE DOWN A BIT FOR THE AFTN...
ESPECIALLY OVER THE E...CLOSER TO SFC HIGH PRES CENTER. AS THE HIGH
MOVES AWAY FROM THE UPPER LAKES TONIGHT...GRADIENT SHOULD REMAIN
WEAK ENOUGH TO KEEP WINDS UNDER 20KT.
ANOTHER PERIOD OF STRONGER WINDS WILL BE POSSIBLE THURSDAY INTO
THURSDAY EVENING...WITH N-NW GUSTS OF 25-30KTS OVER MAINLY CENTRAL AND E
LAKE SUPERIOR...AS STRONG HIGH PRESSURE NEARS FROM S CENTRAL
CANADA AND LOW PRESSURE EXITS ACROSS QUEBEC.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...JLB
MARINE...KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
643 AM CDT SUN SEP 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT SUN SEP 8 2013
THUNDERSTORMS IN PROGRESS EARLY THIS MORNING OVER THE DAKOTAS ARE
BEING AIDED BY LOW LEVEL MOISTURE TRANSPORT FROM THE SOUTHEAST...MID
LEVEL FRONTOGENESIS AND A COUPLED JET ALOFT OVER THE NORTHERN
PLAINS. THIS PATTERN WILL SHIFT SLOWLY EASTWARD TODAY. THIS WILL
LIKELY ALLOW SOME OF THE SHOWERS AND ISOLATED THUNDERSTORMS TO REACH
INTO CENTRAL MN. HOWEVER...A WEAKENING TREND SHOULD DEVELOP AS THE
ACTIVITY OUTRUNS THE LOW LEVEL MOISTURE TRANSPORT AND INSTABILITY
GRADIENT. THE 00Z CAMS FAILED ON DEVELOPING THIS CONVECTION AND
REALLY DON/T HAVE A CLUE ON WHAT IS OCCURRING ATTM. AN EXCEPTION IS
THE HRRR...WITH HOURLY UPDATES...WHICH SHOWS THE POTENTIAL FOR
SHOWERS TO PROGRESS ALL THE WAY TO KEAU BY THE MIDDLE OF THE
AFTERNOON. FOR NOW...ALLOWED SHOWER AND ISOLATED THUNDERSTORM
ACTIVITY TO REACH THE TWIN CITIES BY EARLY THIS AFTERNOON BEFORE
GOING INTO A HOLDING PATTERN. IN ADDITION...EXTENSIVE LOW
CLOUDINESS HAS FORMED ONCE AGAIN OVERNIGHT ACROSS SOUTHERN WI AT
THE BASE OF HIGH PRESSURE OVER LAKE SUPERIOR. THIS CLOUDINESS IS
STREAMING WESTWARD AND WILL OVERTAKE EAST CENTRAL AND SOUTH
CENTRAL MN BY DAYBREAK. THIS COUPLED WITH CLOUDINESS ASSOCIATED
WITH THE SHOWER ACTIVITY TO THE WEST WILL RESULT IN A PARTLY TO
MOSTLY CLOUDY DAY ACROSS THE FA. HIGHS REMAIN ON TRACK WITH UPPER
70S TO LOWER 80S.
A LOW LEVEL JET IS PROGGED TO INCREASE TO OVER 60 KNOTS TONIGHT
ACROSS THE EASTERN DAKOTAS IN ADVANCE OF A LOW PRESSURE SYSTEM
DEVELOPING OVER THE WESTERN HIGH PLAINS. EVERYTHING CONTINUES TO
POINT TO A CONVECTIVE COMPLEX DEVELOPING OVER THE EASTERN DAKOTAS
AND ADVANCING ENE INTO NORTHERN MN BY DAYBREAK MONDAY. THE MAIN
CONCERN FOR THE FA IS HOW FAR SOUTH THUNDERSTORM DEVELOPMENT WILL
OCCUR. THE ARW AND NMM WRF APPEAR TO DEVELOP CONVECTION TO FAR SOUTH
INTO SOUTHERN MN BASED ON RECENT PERFORMANCE. THE SPC WRF HAS
CONVECTION DEVELOPING ALONG AND NORTH THE I-94 CORRIDOR WHICH AGREES
MORE WITH OUR THINKING HERE THE PAST FEW NIGHTS BASED ON THE LOW
LEVEL WAA AND MID LEVEL FRONTOGENETIC PATTERN. THIS ALSO GOES ALONG
WITH THE UPGLIDE/ADIABATIC OMEGA PATTERN SEEN ON THE 310/315K THETA
SURFACES. THEREFORE...CONTINUED WITH CHANCE POPS ACROSS ABOUT THE
NORTHERN HALF OF THE CWA TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 359 AM CDT SUN SEP 8 2013
MODELS IN GOOD AGREEMENT ON EVOLUTION OF THE UPPER AIR PATTERN
THROUGH THE WORK WEEK...WITH A POSITIVELY TILTED TROUGH WORKING
ACROSS THE UPPER MS VALLEY MONDAY THROUGH TUESDAY. FOR THE SECOND
HALF OF THE WEEK...ANOTHER HIGHLY AMPLIFIED WRN RIDGE ERN TROUGH
PATTERN WILL SET IN...WITH COOLER AND DRY NW FLOW RETURNING. BY THE
WEEKEND... THIS RIDGE LOOKS TO FLATTEN OUT AS IT PUSHES EAST INTO
THE PLAINS. IN ADDITION...ANOTHER WAVE LOOKS TO BE TOPPING THE RIDGE
THIS WEEKEND...WITH THE NEXT CHANCE FOR RAIN RETURNING THEN.
ALL SIGNS CONTINUE TO POINT TO NEAR RECORD HEAT TO START THIS PERIOD
ON MONDAY. BY 7PM MONDAY...MODELS SHOW A SFC LOW LOCATED BETWEEN THE
TWIN CITIES AND DULUTH...WITH A COLD FRONT TRAILING TO THE SW TO
NEAR THE SD/MN/IA BORDER. THIS PUTS SRN/ERN MN INTO WRN WI IN THE
HEART OF AN IMPRESSIVE WARM NOSE...WITH THE GFS AND ECMWF SHOWING
925 MB TEMPS BETWEEN 30 AND 32 C...WHICH SUPPORT HIGHS MAKING A RUN
FOR 100 WITHIN THE WARM SECTOR. BACK TRACKING THIS WARM PLUME FROM
MONDAY AFTERNOON TO WHERE MODELS INITIALIZED IT AT 00Z SHOWS THE AIR
FOR MONDAY ORIGINATING FROM THE CO/KS/NEB REGION...WHERE SATURDAY
AFTERNOON HIGHS WERE ALL A COUPLE OF DEGREES ON EITHER SIDE OF 100.
THEREFORE...MAINTAINED CURRENT FORECAST HIGHS...EVEN INCREASING THEM
A NUDGE. AS FOR RECORDS...THEY ARE TOUGH TO ATTAIN BETWEEN SEPTEMBER
8TH AND 11TH...AS THIS FOUR DAY STRETCH CORRESPONDS TO WHAT IS STILL
THE HEAT WAVE OF RECORD FOR SEPTEMBER FROM BACK IN 1931...BUT WE
WILL STILL BE VERY CLOSE COME MONDAY.
OF COURSE THERE IS A POTENTIAL TROUBLE MAKER LURKING IN THE SHADOWS
FOR MONDAY...AND THAT IS THE POTENTIAL FOR THUNDERSTORMS SUNDAY
NIGHT INTO MONDAY MORNING AND ANY CLOUD COVER THEY LEAVE BEHIND. THE
MOST EXTREME EXAMPLE OF THIS WOULD BE THE HIRES-ARW...WHICH HAS
HIGHS IN THE UPPER 90S IN SOUTH CENTRAL MINNESOTA...BUT ONLY HAS A
HIGH OF 83 /16 DEGREES COOLER THAN WHAT WE A CURRENTLY GOING WITH!/
THANKS TO THE MCS IT BRINGS DOWN I-94 MONDAY MORNING. HOWEVER...AS
STATED IN THE SHORT TERM...THE HIRES MODELS LOOK BE TOO FAR SOUTH
WITH ACTIVITY SUNDAY NIGHT. INSTEAD...WILL CONTINUE TO FOLLOW THE
IDEAS OF THE DETERMINISTIC MODELS WITH MAJORITY OF ACTIVITY
FOLLOWING THE FORCING ACROSS NRN MN...LEAVING THE MPX AREA MAINLY
DRY.
WITH THE CURRENT FORECAST...THERE CONTINUES TO BE FIRE WEATHER
CONCERNS...SEE FIRE WEATHER SECTION FOR MORE ON THAT.
UNFORTUNATELY...WE LOOK TO FURTHER BAKE THE LANDSCAPE MONDAY...BUT
NOT GIVE IT MUCH OF A DRINK AS THE COLD FRONT SWINGS THROUGH MONDAY
NIGHT INTO TUESDAY MORNING. DID CUT BACK ON POPS IN THIS
PERIOD...CAPPING THEM IN THE 30S AS ONLY SCATTERED CONVECTION IS
EXPECTED MAINLY BEHIND THE FRONT AS PROGRESSIVE HEIGHT FALLS FINALLY
HELP BREAK DOWN THE CAP ENOUGH TO GENERATE CONVECTION LATE MONDAY.
GIVEN DEEP...WELL MIXED INVERTED-V SOUNDINGS EXPECTED ON
MONDAY...ANY STRONGER CONVECTION WILL POSE A WIND THREAT.
TUESDAY AND WEDNESDAY WILL STILL SEE HIGHS IN THE UPPER 70S TO LOWER
80S /ABOUT 5 DEGREES ABOVE NORMAL/...BUT THE ARRIVAL A LARGE DOME OF
HIGH PRESSURE FROM CANADA ON THURSDAY WILL BRING WITH IT MORE FALL
LIKE WEATHER TO END THE WEEK. OF COURSE HIGHS FROM CANADA DO NOT
BRING WHAT WE COULD REALLY USE AT THE MOMENT...RAINFALL...WITH IT
LOOKING DRY FROM TUESDAY AFTERNOON TROUGH THE REST OF THE WORK WEEK.
NEXT WEEKEND...THE GFS/ECMWF CONTINUE TO SHOW A SHORTWAVE TOPPING
THE RIDGE AND WORKING ACROSS THE NORTH CENTRAL CONUS. WE BEGIN TO
SEE MOISTURE RETURN ON SATURDAY...WITH AT LEAST SOME HOPE FOR SOME
RAINFALL OVER THE WEEKEND. HAVE SEEN THE MODELS SLOW THIS MOISTURE
RETURN SOME...BUT THERE IS STILL HOPE FOR SOME RAIN SATURDAY INTO
SUNDAY...THOUGH STILL PLENTY OF TIME FOR THE MODELS TO FIGURE OUT A
WAY TO SEND THIS PRECIP ACROSS NRN MN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 630 AM CDT SUN SEP 8 2013
TWO ISSUES TO DEAL WITH THIS MORNING. FIRST...AN AREA OF MVFR
CEILINGS BETWEEN 010-020... THAT DEVELOPED ACROSS SOUTHERN WI DURING
THE EVENING... HAS SPREAD WESTWARD INTO SOUTHERN MN AND WEST CENTRAL
WI. THE RAP 0.5KM CPD HAS HAD AN EXCELLENT HANDLE ON THIS. IT
SUGGESTS THESE CEILINGS WILL SPREAD ACROSS KRWF AND KSTC EARLY
THIS MORNING AND PERHAPS REACH KAXN BY 15Z. THE BAND OF LOW
CEILINGS THEN DISSIPATES DURING THE EARLY AFTERNOON. THE BACK EDGE
OF THIS CLOUDINESS HAS CLEARED KEAU AND WILL BE CLEARING KRNH IN
AN HOUR OR TWO. THE SECOND ISSUE TODAY IS THE THREAT FOR SHOWERS
AND ISOLATED THUNDERSTORMS DEVELOPING AHEAD OF AN MCV NORTH OF
KABR. THIS CIRCULATION WAS BORN OUT OF COMPLEX OF STORMS THAT
DEVELOPED TO THE WEST EARLIER IN THE NIGHT. ALTHOUGH THIS
CIRCULATION IS MOVING AWAY FROM THE BEST LOW LEVEL MOISTURE FEED
AND INSTABILITY GRADIENT... SHOWERS AND A FEW THUNDERSTORM HAVE
ALREADY REACHED KAXN. THE CAMS HAVE NOT HANDLED THIS WELL AT ALL
WITH ONLY THE HRRR SHOWING A CONTINUED DOWNWARD TREND TO THE
ACTIVITY AS IT MOVES ACROSS CENTRAL MN THIS MORNING AND INTO WEST
CENTRAL WI THIS AFTERNOON. THEREFORE... VCSH/VCTS IN AT THE MN TAF
SITES THIS THIS MORNING.
TONIGHT POSES ANOTHER PROBLEM AS A WARM FRONT LIFTS NORTHWARD
ACROSS THE TAF SITES. METEOROLOGICAL REASONING WOULD SUGGEST MOST
OF THE SHOWERS AND THUNDERSTORMS THAT DO DEVELOP WOULD OCCUR
ACROSS CENTRAL MN AND WEST CENTRAL WI. CERTAINLY NOT WHAT THE CAMS
INDICATE WITH ACTIVITY SPREAD CLEAR SOUTH TO THE IA BORDER. KEPT
THE MENTION TO VCSH AT THIS POINT DUE TO THE UNCERTAINTY OF NOT
ONLY THE LOCATION BUT AS TO WHETHER OR NOT ANYTHING OCCURS. IT MAY
END UP WELL TO THE NORTH OF US. THERE IS ALSO AN INDICATION THAT
MORE MVFR CEILINGS WILL DEVELOP THIS EVENING ACROSS SOUTHERN WI
AND SPREAD INTO EASTERN MN AND WESTERN WI DURING THE NIGHT.
CONFIDENCE IS NOT HIGH BUT INDICATE SOME SCT015-20 FOR NOW.
KMSP...
MVFR CEILINGS GRADUALLY LIFTING AND BREAKING UP THIS MORNING. THE
BACK EDGE IS CURRENTLY ABOUT 30 MILES SE OF THE AIRFIELD. SOME
VFR SHOWERS ARE EXPECTED AROUND NOON AND THROUGH A FEW HOURS OF
THE AFTERNOON. MAINLY DRY TONIGHT BUT AN ISOLATED SHRA/TSRA CAN
NOT BE RULE OUT BETWEEN 06Z-12Z. MORE NUMEROUS ACTIVITY SHOULD BE
WELL TO THE NORTH AND EAST OF THE AIRFIELD. A REPEAT OF THE MVFR
CEILINGS MAY OCCUR TONIGHT. CONFIDENCE IS NOT HIGH AT THIS
POINT... BUT NEWER DATA THIS MORNING SUGGESTS THE POSSIBILITY BY
04Z AND LASTING TO NEAR DAYBREAK. EASTERLY WINDS NEAR 10 KNOTS
TODAY AND THEN SE TONIGHT AND EARLY MONDAY.
/OUTLOOK FOR KMSP/
MON NGT...VFR. CHC MVFR/TRW. W WINDS 10 KTS.
TUE...VFR. CHC RW EARLY. W WINDS 5-10 KTS.
WED...VFR. NW WINDS 10 KTS.
&&
.FIRE WEATHER...
ISSUED AT 359 AM CDT SUN SEP 8 2013
CURRENT FORECAST CONTINUES TO POINT TOWARD A POTENTIALLY SEVERE
FIRE WEATHER DANGER DAY ON MONDAY...ESPECIALLY FROM SOUTHERN INTO
EAST CENTRAL MN. HIGH TEMPERATURES IN THE AREA OF CONCERN WILL
WARM INTO THE UPPER 90S...WHILE DEW POINTS LOWER INTO THE MID 50S.
THIS SCENARIO WOULD YIELD MINIMUM RELATIVE HUMIDITY VALUES NEARING
25 PERCENT ON MONDAY AFTERNOON...WHEN SOUTHERLY WINDS WILL ALSO BE
ON THE BREEZY SIDE AT SPEEDS OF 15 TO 20 MPH. WHILE VEGETATION IS
STILL RATHER GREEN...THE PRECIPITATION DEFICITS OVER THE LAST
MONTH AND THE MOUNTING DROUGHT CONDITIONS ARE OF NOTABLE CONCERN.
MAIN SOURCE OF UNCERTAINTY FOR THIS FORECAST IS THE POTENTIAL FOR
THUNDERSTORMS INTO MONDAY MORNING...WITH RESULTANT CLOUD COVER
RESTRICTING HIGHS A BIT MORE THAN FORECAST FOR EASTERN MN INTO
WI...THOUGH HIGHEST PROBABILITY FOR THUNDERSTORMS SUNDAY NIGHT
INTO MONDAY REMAIN NORTH OF THE MPX AREA.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...RAH
LONG TERM...MPG
AVIATION...RAH
FIRE WEATHER...MPG
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1236 PM CDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 1236 PM CDT SUN SEP 8 2013
FCST IS EVOLVING FAIRLY CLOSE TO EXPECTATIONS. THIS IS A COMPLEX
SITUATION WITH TSTM OUTFLOW SHIFTING WINDS TO THE NE OVER S-CNTRL
NEB AND MAINTAINING HIGHER DWPTS...AND EVEN ADVECTING THEM BACK
SWD. THIS IS NOT WHAT WAS ANTICIPATED VIA THE MODELS. THE SFC
TROF WAS FCST TO LIFT BACK N AND IT STILL WILL...BUT LATER THAN
PLANNED. THE DECISION TO LOWER HIGHS LOOKS VERY VERY GOOD /SEE
PRVS UPDATE/. MODEST CONVERGENCE WILL BE OVER THE FCST AREA AND
HI-RES MODELS WITH EXPLICIT CONVECTION ARE FCSTG A TSTM OR TWO TO
DEVELOP AFTER 4 PM. SO A LOW 20 PERCENT POP HAS BEEN EXPANDED TO
THE ENTIRE FCST AREA DUE TO INHERENT UNCERTAINTY.
WE ARE CONTEMPLATING A RED FLAG WRNG FOR OUR N-CNTRL KS COUNTIES
TOMORROW AFTN...PENDING REVIEW OF ADDITIONAL 12Z GUIDANCE.
PROBABILITY OF ISSUANCE 80 PERCENT.
UPDATE ISSUED AT 936 AM CDT SUN SEP 8 2013
FCST HAS BEEN UPDATED TO LOWER HIGHS WHERE FOG IS INHIBITING
HEATING /ALONG AND N OF I-80/ AND WHERE THE APPROACHING OUTFLOW
MAY ALSO KEEP TEMPS DOWN. ALSO LOWERED DWPTS PER REASONING FROM
THE PRVS UPDATE. WIND DIRECTION HAS BEEN ADJUSTED THRU MIDDAY TO
ALLOW FOR WIND SHIFT TO NE BEHIND THE BOUNDARY.
UPDATE ISSUED AT 908 AM CDT SUN SEP 8 2013
THE DENSE FOG ADVY HAS BEEN EXTENDED ONE MORE HOUR PER WEBCAMS...
AIRPORT VSBYS AND VIS SATELLITE. USING CONDITIONAL CLIMATOLOGY
/LOOKING BACK AT PAST SIMILAR EVENTS DURING AUG-SEP/ THE
PROBABILITY OF IFR CIG/VSBY CONTS VERY HIGH /81 PERCENT/ THRU 14Z
AND THEN DROPS TO 62 PERCENT 15Z AND 38 PERCENT BY 16Z.
SATELLITE SHOWS A DRY OUTFLOW BOUNDARY FROM OVERNGT TSTMS
APPROACHING NEB HWY 92. THIS WILL SHIFT WINDS TO NE AS ALREADY
SEEN AT ODX/BVN. THIS WILL COMPLICATE THE FCST HIGHS TODAY AND
DEPENDING ON ITS DENSITY IT MAY PREVENT THE E-W TROF FROM LIFTING
BACK N.
MRNG DATA DIAGNOSIS IS STILL ON-GOING...BUT ENVISION DWPTS WILL
NEED TO BE LOWERED SUBSTANTIALLY S AND W OF THE TRI-CITIES. HIGH
TEMPS IN THE 100S VIRTUALLY GUARANTEES MIN RH DROPPING INTO THE
TEENS THIS AFTN.
MORE LATER...
UPDATE ISSUED AT 706 AM CDT SUN SEP 8 2013
WITHIN THE PAST HOUR...DENSE FOG HAS EXPANDED IN COVERAGE EASTWARD
ACROSS MOST COUNTIES MAINLY ALONG/NORTH OF THE INTERSTATE 80
CORRIDOR PER AUTOMATED AIRPORT OBS AND WEBCAMS...WHILE
MAINTAINING INTENSITY FARTHER SOUTHWEST INTO THE HOLDREGE AREA AS
WELL. AS A RESULT...HAVE ADDED SEVERAL MORE COUNTIES TO THE DENSE
FOG ADVISORY...WHICH NOW INCLUDES GENERALLY ALL AREAS NORTH OF AN
ELWOOD-HASTINGS-YORK LINE. THE LATEST HRRR VISIBILITY PRODUCT HAS
CAPTURED THE AREA OF DENSE FOG FAIRLY WELL...AND SUGGESTS MOST OF
IT SHOULD LIFT/IMPROVE CONSIDERABLY BY 9 AM OR SO...BUT COULD
MAYBE LINGER CLOSER TO 10 AM IN THE CORE OF THE FOG AREA. INCOMING
DAY SHIFT WILL MONITOR TRENDS AND ADJUST HEADLINE AS NECESSARY.
UPDATE ISSUED AT 546 AM CDT SUN SEP 8 2013
WENT AHEAD WITH A DENSE FOG ADVISORY FOR A FEW HOURS THIS MORNING
FOR AREAS GENERALLY WEST OF HIGHWAY 281 AND ALONG THE INTERSTATE
80 CORRIDOR WHERE VSBY AVERAGE ONE QUARTER MILE OR LESS. VSBYS
WILL IMPROVE AFTER SUNRISE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 453 AM CDT SUN SEP 8 2013
AN UPPER LEVEL RIDGE OF HIGH PRESSURE CONTINUES TO DOMINATE THE
WEATHER PATTERN ACROSS THE INTERIOR CONUS...RESULTING IN HOT
TEMPERATURES FOR EARLY SEPTEMBER...WELL ABOVE NORMAL. AT THE
SURFACE...LOW PRESSURE WAS CENTERED ALONG THE WY/NEB BORDER...WITH
A STALLED FRONTAL BOUNDARY EXTENDING EASTWARD ALONG THE NEB/KS
STATELINE. HIGH DPS IN THE UPPER 60S TO AROUND 70 HAVE POOLED NORTH
OF THE BOUNDARY AND IN PRESENCE OF THE LLVL MOISTURE...SOME PATCHY
FOG HAS DEVELOPED WITH THE LOWEST VSBYS SO FAR AROUND ONE OR TWO
MILES. WILL CONTINUE TO MONITOR VSBY TRENDS THRU THE PRE DAWN
HOURS AS MODELS ARE NOT IN AGREEMENT ON HOW SIGNIFICANT FOG WILL BE
...AND THE HRRR SUGGESTS POTENTIAL FOR DENSE FOG.
THE FRONTAL BOUNDARY ALONG THE NEB/KS STATELINE WILL LIFT NORTH AS A
WARM FRONT TODAY AND TEMPERATURES WILL BE TOASTY WITH READINGS
RISING WELL INTO THE 90S...AND OUR WESTERN/SOUTHERN ZONES WILL BE
EVEN WARMER WITH HIGHS IN THE 100 TO 105F RANGE. HEAT INDICES WILL
BE FAIRLY CLOSE OR JUST BELOW AMBIENT TEMPS AS DPS LOWER BEHIND
BOUNDARY...AND SHOULD REMAIN SHY OF HEAT ADVISORY CRITERIA.
CANNOT COMPLETELY RULE OUT THE POTENTIAL FOR AN ISOLATED
THUNDERSTORM THIS AFTERNOON/EVENING...GENERALLY NORTH OF INTERSTATE
80 AS THE WARM FRONTAL BOUNDARY LIFTS ACROSS. MODELS INDICATE
PRESENCE OF MID LEVEL WAA AND FRONTOGENESIS BETWEEN H85 AND H7 NORTH
OF I-80 AND DAYTIME HIGHS ARE RIGHT AROUND CONVECTIVE TEMPERATURES.
BOTH THE NAM/GFS INDICATE THE LIFT/FORCING...BUT ONLY THE 4KM SPC
WRF INDICATES DEVELOPMENT. THE CONVECTIVE POTENTIAL IS LIMITED WITH
CAPPING/WARM MID LEVEL TEMPS...BUT CANNOT RULE OUT AN ISOLATED CHC
AND HAVE ADDED SMALL POPS.
DRY AND MILD CONDITIONS ARE FORECAST LATE EVENING ON...WITH LOWS
AVERAGING IN THE UPPER 60S TO AROUND 70F.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 453 AM CDT SUN SEP 8 2013
THERE CONTINUES TO REMAIN A FAIRLY CONSISTENT FORECAST THEME
THROUGH THESE 6 DAYS...WITH MONDAY FEATURING THE FINALE OF A
MEMORABLE EARLY SEPTEMBER HOT SPELL...ALTHOUGH TUESDAY STILL LOOKS
PLENTY TOASTY AS WELL ACROSS ROUGHLY THE SOUTHEASTERN 1/3 OF THE
CWA WITH HIGHS BETWEEN 90-95. THEREAFTER...THE WED-SAT TIME FRAME
IS EXPECTED TO FEATURE HIGHS PREDOMINANTLY IN THE 80S...WHICH ON
SEVERAL DAYS WILL STILL BE A FEW DEGREES ABOVE NORMAL DESPITE
BEING MORE SEASONABLE. AS FOR SHOWER/THUNDERSTORM CHANCES...THERE
REMAINS AT LEAST A SLIGHT CHANCE MENTION IN THE FORECAST FOR AT
LEAST A PORTION OF THE OUTLOOK AREA DURING EVERY PERIOD FROM
MONDAY NIGHT THROUGH FRIDAY NIGHT...WITH SATURDAY VOID OF
MENTIONABLE POPS...AT LEAST FOR NOW. IF ANYTHING...UNCERTAINTY
CONTINUES TO GROW REGARDING WHICH OF THESE PERIODS MIGHT BE
FAVORED FOR MORE WIDESPREAD PRECIPITATION COVERAGE...SO FOR NOW
MOST OF THESE CHANCES CONTINUE TO BE HELD DOWN IN THE 20-30
PERCENT RANGE. AS DISCUSSED OVER THE PAST 24 HOURS...MONDAY COULD
POTENTIALLY FEATURE SOME OF THE HIGHEST FIRE DANGER THE LOCAL AREA
HAS SEEN THIS SUMMER...AND THESE CONCERNS ARE OUTLINED IN GREATER
DETAIL IN THE SEPARATE FIRE WEATHER SECTION BELOW.
STARTING WITH MONDAY/MONDAY NIGHT...THE LATEST 00Z/06Z MODELS ARE
IN GOOD AGREEMENT ON THE BIG PICTURE ALOFT...WITH THE LOCAL AREA
EXPERIENCING SOUTHWESTERLY FLOW ALOFT AS THE CENTER OF THE
EXPANSIVE RIDGE AXIS CURRENTLY PARKED OVERHEAD CONTINUES TO DRIFT
FARTHER AWAY INTO THE SOUTHEAST STATES...AS A PROGRESSIVE
SHORTWAVE TROUGH TRANSLATES ALONG THE U.S./CANADA BORDER FROM A
CENTRAL POSITION OVER NORTHERN MT AT SUNRISE MONDAY...TO NORTHERN
MN BY SUNRISE TUESDAY. IN RESPONSE...A MODEST COLD FRONT WILL
DRIFT SOUTHEASTWARD INTO THE CENTRAL PLAINS. DURING THE DAYTIME
MONDAY...THE CWA WILL REMAIN JUST AHEAD OF THIS COLD FRONT...WHICH
IS FORECAST TO ALIGN FROM NORTHEAST TO TO NORTH CENTRAL NEB BY
LATE AFTERNOON...BEFORE SLOWLY INFILTRATING MUCH OF THE
NORTHERN/CENTRAL CWA MONDAY NIGHT. THE DAYTIME HOURS SHOULD BE
ANOTHER HOT ONE AREA-WIDE...AS SUSTAINED SOUTH-SOUTHWEST WINDS
PICK UP TO AT LEAST 15-20 MPH WITH GUSTS 25+ MPH IN MOST
AREAS...EXCEPT FOR A BIT LIGHTER SPEEDS POSSIBLE IN FAR NORTHWEST
COUNTIES IN CLOSET PROXIMITY TO THE APPROACHING TROUGH AXIS. WITH
DEEP MIXING FORECAST TO AVERAGE UP TO AROUND 750 MILLIBARS OVER
MUCH OF THE CWA...ANTICIPATE DEWPOINTS TO FALL WELL DOWN INTO THE
50S DURING THE AFTERNOON...WITH 40S IN SEVERAL SOUTHWESTERN
COUNTIES. IN THEORY...THIS SETUP SHOULD SET THE STAGE FOR SOME OF
THE HOTTEST READINGS OF THIS ENTIRE HOT STRETCH...ESPECIALLY IN
CENTRAL/NORTHEAST COUNTIES...BUT SOMEWHAT ODDLY MET/MAV GUIDANCE
SUGGESTS HIGHS MONDAY WOULD BE A TOUCH COOLER THAN THOSE TODAY.
DESPITE THIS...HAVE KEPT FORECAST HIGHS AT LEAST A FEW DEGREES
ABOVE A GUIDANCE BLEND IN MOST AREAS...WITH ALL BUT THE FAR
NORTHERN CWA AIMED TO TOP OUT SOMEWHERE IN THE 98-103 RANGE...WITH
THE HIGHER END OF THIS RANGE IN FAR SOUTHERN/SOUTHWEST COUNTIES.
DUE TO THE LOWER DEWPOINTS...HEAT INDEX VALUES IN MOST AREAS ONLY
AVERAGE 95-100 DEGREES. AS FOR STORM CHANCES...MODELS VARY ON HOW
AGGRESSIVELY CONVECTION MAY TRY TO SLIP INTO OUR FAR NORTHWEST
ZONES MONDAY EVENING/NIGHT...WITH SOME BRINGING THEM JUST IN WHILE
OTHERS KEEP THEM JUST OUTSIDE. GIVEN THE SLOWING NATURE OF THE
SURFACE FRONT...HAVE BACKED OFF MON NIGHT POPS TO ONLY ABOUT THE
NORTHWESTERN 1/4 OF THE CWA...WHILE THE VAST MAJORITY OF THE CWA
STAYS DRY. ALTHOUGH ANY MARGINAL SEVERE THREAT DURING THE LATE
AFTERNOON/EVENING SHOULD LARGELY TARGET THE SANDHILLS REGION JUST
TO OUR NORTHWEST...SUPPOSE A STRONG TO MARGINALLY SEVERE STORM OR
TWO CANNOT BE RULED OUT SLIPPING INTO OUR AREA...WITH THE MAIN
THREAT BEING GUSTY WINDS DUE TO HIGH CLOUD BASES IN THE DEEPLY-
MIXED AIRMASS NEAR THE FRONT. SEVERE PARAMETERS ARE NOT ALL THAT
IMPRESSIVE...WITH THE GFS SUGGESTING EARLY EVENING CAPE AVERAGING
WELL UNDER 1000 J/KG...ALTHOUGH DEEP LAYER SHEAR ISN/T ALL THAT
POOR AROUND 30-40 KNOTS.
TUESDAY/TUES NIGHT...THE NORTHERN MN SHORTWAVE TROUGH QUICKLY
SLIDES EAST INTO SOUTHEAST CANADA...AND ALTHOUGH THE CWA SEES A
PERIOD OF DECENT UPPER JET ENTRANCE REGION LIFT AND ASSOCIATED MID
LEVEL FRONTOGENESIS...THE MAIN FORCING STEADILY SLIDES AWAY TO THE
NORTHEAST...ALLOWING THE SURFACE FRONT TO LOSE STEAM AND GENERALLY
STALL OUT WITHIN OR NEAR THE SOUTHERN EDGE OF THE CWA BY TUESDAY
AFTERNOON/NIGHT. THERE COULD BE A DECENT TEMP GRADIENT IN HIGHS
TUESDAY AFTERNOON...AND HAVE MADE LITTLE CHANGE...STILL AIMING FOR
LOW-MID 80S NORTHWEST TO LOW-MID 90S SOUTHEAST. IF ENOUGH
INSTABILITY BUILDS ALONG THE SURFACE BOUNDARY...COULD MAYBE SEE
SOME STRONG TO SEVERE NEAR-SURFACE BASED STORMS FLARE UP IN
SOUTHERN COUNTIES TUESDAY AFTERNOON/EVENING...WITH MORE ELEVATED
ACTIVITY DEVELOPING FARTHER NORTH AS THE NIGHT WEARS ON IN RESPONSE
TO MID-LEVEL THETA-E ADVECTION. EVEN ONLY 3 DAYS
AWAY...UNCERTAINTY IS VERY HIGH HERE...AND HAVE KEPT DAYTIME POPS
IN SLIGHT CHANCE RANGE...WITH A GREATER COVERAGE OF 30 POPS
TUESDAY NIGHT.
WEDNESDAY THROUGH FRIDAY NIGHT...THERE CONTINUES MULTIPLE...MAINLY
20-30 PERCENT POPS ACROSS ALL/MOST OF THE CWA...AND OBVIOUSLY A
LOT OF FINE-TUNING WILL NEED DONE HERE IN THE COMING DAYS. ON THE
LARGE SCALE ALOFT...THE LOCAL AREA SETS UP UNDER FAIRLY WEAK WEST-
SOUTHWEST FLOW ALOFT...IN THE WAKE OF A DEEPENING TROUGH MIGRATING
ACROSS SOUTHEAST CANADA/THE NORTHEAST CONUS...AND ALONG THE
NORTHERN PERIPHERY OF AN EXPANSIVE SOUTHERN CONUS RIDGE
AXIS...WHICH INSTEAD OF BEING OVERHEAD AS THE CURRENT ONE
IS...THIS TIME SETS UP FARTHER SOUTH MORE OVER OK/TX. WITH THE
REMNANT...GENERALLY EAST-WEST SURFACE FRONT REMAINING IN PLACE
NEAR OR OVER THE CWA DURING THE TIME...AND WITH THE AREA BEING
PRONE TO MAINLY NOCTURNAL INCREASES IN THETA-E ADVECTION IN THE
850-700MB LAYER...THERE COULD BE SEVERAL ROUNDS OF
SHOWERS/STORMS...AND MAYBE EVEN AN OCCASIONAL SEVERE THREAT. TEMP-
WISE...LITTLE CHANGE FROM PREVIOUS WITH HIGHS GENERALLY LOW-MID
80S MOST AREAS...ALTHOUGH SOME 70S NOT OUT OF THE QUESTION.
SATURDAY...HAVE LEFT OUT POPS FOR NOW DUE TO INCREASING MODEL
VARIABILITY AND UNCERTAINTY AT THIS TIME RANGE..BUT DRY IS NO
GUARANTEE...WITH THE LOCAL AREA REMAINING NORTH OF THE SOUTHERN
PLAINS RIDGE AND POSSIBLY IN THE PATH OF SOME LOW AMPLITUDE
DISTURBANCES BRUSHING BY THROUGH THE NORTHERN PLAINS. WILL CALL
FOR MAINLY MID 80S IN NEB ZONES AND UPPER 80S IN KS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1236 PM CDT SUN SEP 8 2013
THIS AFTN: VFR SKC...BUT A FEW CU MAY DEVELOP AROUND 9K FT. ONE OR
TWO COULD DEVELOP INTO A CB/TSTM. WILL MONITOR THRU THE AFTN.
WHILE WINDS ARE CURRENTLY LGT FROM THE N...EXPECT A SHIFT TO SE
SOMETIME THIS AFTN.
TNGT: A VERY LOW PROBABILITY FOR A VCTS THRU 02Z. THEN VFR SKC. S
WINDS WILL AVERAGE 10 KTS. CURRENTLY WE DO NOT EXPECT FOG TO
REDEVELOP. AS WINDS FRESHEN FROM THE S...THIS SHOULD ADVECT DRIER
AIR IN FROM THE S.
MON THRU 18Z: VFR SKC. SSW WINDS BECOME GUSTY 15Z-16Z WITH GUSTS
UP TO 26 KTS.
CIG CONFIDENCE: HIGH
VSBY CONFIDENCE: MEDIUM
WIND CONFIDENCE: MEDIUM
WX CONFIDENCE: MEDIUM
&&
.FIRE WEATHER...
ISSUED AT 453 AM CDT SUN SEP 8 2013
AS PREVIOUSLY DISCUSSED OVER THE PAST 24 HOURS...MONDAY CONTINUES
TO APPEAR A DECENT CANDIDATE FOR NEAR-CRITICAL TO POTENTIALLY
CRITICAL FIRE DANGER ACROSS PARTS OF THE CWA. ON SATURDAY...AREA
FIRE WEATHER MANAGERS DEEMED VEGETATIVE FUELS ACROSS OUR KS ZONES
TO BE DRY ENOUGH TO SUPPORT POSSIBLE HEADLINES...ALTHOUGH FUELS
ACROSS OUR NEBRASKA COUNTIES ARE STILL ASSUMED TO BE GREEN ENOUGH
TO PRECLUDE MAJOR ISSUES BARRING FURTHER INFORMATION. AS LONG AS
FUELS ARE DEEMED FAVORABLE...CRITICAL FIRE WEATHER THRESHOLDS
ACROSS THE GID CWA INCLUDE A COMBINATION OF RELATIVE HUMIDITY
AT/BELOW 20 PERCENT AND SUSTAINED WINDS/GUSTS OF 20 MPH/25 MPH FOR
3+ HOURS. AS THE FORECAST CURRENTLY STANDS...A DECENT OVERLAP OF
THESE WIND/RH PARAMETERS IS ANTICIPATED ACROSS MUCH OF THE
SOUTHWESTERN HALF OF THE CWA MONDAY AFTERNOON...AS INCREASING
SOUTHWESTERLY WINDS ALLOW HOT...DRY AIR TO OVERSPREAD THE AREA.
EVEN IN NORTHEAST PORTIONS OF THE CWA...RH VALUES ARE FORECAST TO
DROP BETWEEN 21-30 PERCENT...SO THERE COULD BE AT LEAST SOME
DEGREE OF FIRE DANGER THERE AS WELL DESPITE THE OVERALL GREENER
FUELS. GIVEN THAT MONDAY AFTERNOON IS STILL 30+ HOURS AWAY AND
STILL SUBJECT TO SOME FINE-TUNING...AND AFTER COORDINATION WITH
SURROUNDING OFFICES...WILL HOLD OFF ON ANY FIRE WEATHER HEADLINES
FOR KS ZONES AT THIS TIME...BUT WILL CONTINUE TO ADVERTISE NEAR-
CRITICAL TO POTENTIALLY CRITICAL CONDITIONS IN THE HAZARDOUS
WEATHER OUTLOOK.
&&
.CLIMATE...
ISSUED AT 453 AM CDT SUN SEP 8 2013
ALTHOUGH CURRENT FORECAST HIGH TEMPERATURES TODAY/MONDAY AT OUR
PRIMARY CLIMATE RECORD SITES GRAND ISLAND/HASTINGS ARE CURRENTLY
FORECAST SLIGHTLY SHY OF RECORDS...IT COULD BE A PRETTY CLOSE
CALL. THOSE RECORDS ARE AS FOLLOWS...
SUNDAY SEP. 8...GRAND ISLAND 101 IN 1931 AND 1928
HASTINGS 101 IN 1931
MONDAY SEP. 9...GRAND ISLAND 104 IN 1931
HASTINGS 102 IN 1919
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...FAY
LONG TERM...PFANNKUCH
AVIATION...HALBLAUB
FIRE WEATHER...PFANNKUCH
CLIMATE...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
937 AM CDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 936 AM CDT SUN SEP 8 2013
FCST HAS BEEN UPDATED TO LOWER HIGHS WHERE FOG IS INHIBITING
HEATING /ALONG AND N OF I-80/ AND WHERE THE APPROACHING OUTFLOW
MAY ALSO KEEP TEMPS DOWN. ALSO LOWERED DWPTS PER REASONING FROM
THE PRVS UPDATE. WIND DIRECTION HAS BEEN ADJUSTED THRU MIDDAY TO
ALLOW FOR WIND SHIFT TO NE BEHIND THE BOUNDARY.
UPDATE ISSUED AT 908 AM CDT SUN SEP 8 2013
THE DENSE FOG ADVY HAS BEEN EXTENDED ONE MORE HOUR PER WEBCAMS...
AIRPORT VSBYS AND VIS SATELLITE. USING CONDITIONAL CLIMATOLOGY
/LOOKING BACK AT PAST SIMILAR EVENTS DURING AUG-SEP/ THE
PROBABILITY OF IFR CIG/VSBY CONTS VERY HIGH /81 PERCENT/ THRU 14Z
AND THEN DROPS TO 62 PERCENT 15Z AND 38 PERCENT BY 16Z.
SATELLITE SHOWS A DRY OUTFLOW BOUNDARY FROM OVERNGT TSTMS
APPROACHING NEB HWY 92. THIS WILL SHIFT WINDS TO NE AS ALREADY
SEEN AT ODX/BVN. THIS WILL COMPLICATE THE FCST HIGHS TODAY AND
DEPENDING ON ITS DENSITY IT MAY PREVENT THE E-W TROF FROM LIFTING
BACK N.
MRNG DATA DIAGNOSIS IS STILL ON-GOING...BUT ENVISION DWPTS WILL
NEED TO BE LOWERED SUBSTANTIALLY S AND W OF THE TRI-CITIES. HIGH
TEMPS IN THE 100S VIRTUALLY GUARANTEES MIN RH DROPPING INTO THE
TEENS THIS AFTN.
MORE LATER...
UPDATE ISSUED AT 706 AM CDT SUN SEP 8 2013
WITHIN THE PAST HOUR...DENSE FOG HAS EXPANDED IN COVERAGE EASTWARD
ACROSS MOST COUNTIES MAINLY ALONG/NORTH OF THE INTERSTATE 80
CORRIDOR PER AUTOMATED AIRPORT OBS AND WEBCAMS...WHILE
MAINTAINING INTENSITY FARTHER SOUTHWEST INTO THE HOLDREGE AREA AS
WELL. AS A RESULT...HAVE ADDED SEVERAL MORE COUNTIES TO THE DENSE
FOG ADVISORY...WHICH NOW INCLUDES GENERALLY ALL AREAS NORTH OF AN
ELWOOD-HASTINGS-YORK LINE. THE LATEST HRRR VISIBILITY PRODUCT HAS
CAPTURED THE AREA OF DENSE FOG FAIRLY WELL...AND SUGGESTS MOST OF
IT SHOULD LIFT/IMPROVE CONSIDERABLY BY 9 AM OR SO...BUT COULD
MAYBE LINGER CLOSER TO 10 AM IN THE CORE OF THE FOG AREA. INCOMING
DAY SHIFT WILL MONITOR TRENDS AND ADJUST HEADLINE AS NECESSARY.
UPDATE ISSUED AT 546 AM CDT SUN SEP 8 2013
WENT AHEAD WITH A DENSE FOG ADVISORY FOR A FEW HOURS THIS MORNING
FOR AREAS GENERALLY WEST OF HIGHWAY 281 AND ALONG THE INTERSTATE
80 CORRIDOR WHERE VSBY AVERAGE ONE QUARTER MILE OR LESS. VSBYS
WILL IMPROVE AFTER SUNRISE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 453 AM CDT SUN SEP 8 2013
AN UPPER LEVEL RIDGE OF HIGH PRESSURE CONTINUES TO DOMINATE THE
WEATHER PATTERN ACROSS THE INTERIOR CONUS...RESULTING IN HOT
TEMPERATURES FOR EARLY SEPTEMBER...WELL ABOVE NORMAL. AT THE
SURFACE...LOW PRESSURE WAS CENTERED ALONG THE WY/NEB BORDER...WITH
A STALLED FRONTAL BOUNDARY EXTENDING EASTWARD ALONG THE NEB/KS
STATELINE. HIGH DPS IN THE UPPER 60S TO AROUND 70 HAVE POOLED NORTH
OF THE BOUNDARY AND IN PRESENCE OF THE LLVL MOISTURE...SOME PATCHY
FOG HAS DEVELOPED WITH THE LOWEST VSBYS SO FAR AROUND ONE OR TWO
MILES. WILL CONTINUE TO MONITOR VSBY TRENDS THRU THE PRE DAWN
HOURS AS MODELS ARE NOT IN AGREEMENT ON HOW SIGNIFICANT FOG WILL BE
...AND THE HRRR SUGGESTS POTENTIAL FOR DENSE FOG.
THE FRONTAL BOUNDARY ALONG THE NEB/KS STATELINE WILL LIFT NORTH AS A
WARM FRONT TODAY AND TEMPERATURES WILL BE TOASTY WITH READINGS
RISING WELL INTO THE 90S...AND OUR WESTERN/SOUTHERN ZONES WILL BE
EVEN WARMER WITH HIGHS IN THE 100 TO 105F RANGE. HEAT INDICES WILL
BE FAIRLY CLOSE OR JUST BELOW AMBIENT TEMPS AS DPS LOWER BEHIND
BOUNDARY...AND SHOULD REMAIN SHY OF HEAT ADVISORY CRITERIA.
CANNOT COMPLETELY RULE OUT THE POTENTIAL FOR AN ISOLATED
THUNDERSTORM THIS AFTERNOON/EVENING...GENERALLY NORTH OF INTERSTATE
80 AS THE WARM FRONTAL BOUNDARY LIFTS ACROSS. MODELS INDICATE
PRESENCE OF MID LEVEL WAA AND FRONTOGENESIS BETWEEN H85 AND H7 NORTH
OF I-80 AND DAYTIME HIGHS ARE RIGHT AROUND CONVECTIVE TEMPERATURES.
BOTH THE NAM/GFS INDICATE THE LIFT/FORCING...BUT ONLY THE 4KM SPC
WRF INDICATES DEVELOPMENT. THE CONVECTIVE POTENTIAL IS LIMITED WITH
CAPPING/WARM MID LEVEL TEMPS...BUT CANNOT RULE OUT AN ISOLATED CHC
AND HAVE ADDED SMALL POPS.
DRY AND MILD CONDITIONS ARE FORECAST LATE EVENING ON...WITH LOWS
AVERAGING IN THE UPPER 60S TO AROUND 70F.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 453 AM CDT SUN SEP 8 2013
THERE CONTINUES TO REMAIN A FAIRLY CONSISTENT FORECAST THEME
THROUGH THESE 6 DAYS...WITH MONDAY FEATURING THE FINALE OF A
MEMORABLE EARLY SEPTEMBER HOT SPELL...ALTHOUGH TUESDAY STILL LOOKS
PLENTY TOASTY AS WELL ACROSS ROUGHLY THE SOUTHEASTERN 1/3 OF THE
CWA WITH HIGHS BETWEEN 90-95. THEREAFTER...THE WED-SAT TIME FRAME
IS EXPECTED TO FEATURE HIGHS PREDOMINANTLY IN THE 80S...WHICH ON
SEVERAL DAYS WILL STILL BE A FEW DEGREES ABOVE NORMAL DESPITE
BEING MORE SEASONABLE. AS FOR SHOWER/THUNDERSTORM CHANCES...THERE
REMAINS AT LEAST A SLIGHT CHANCE MENTION IN THE FORECAST FOR AT
LEAST A PORTION OF THE OUTLOOK AREA DURING EVERY PERIOD FROM
MONDAY NIGHT THROUGH FRIDAY NIGHT...WITH SATURDAY VOID OF
MENTIONABLE POPS...AT LEAST FOR NOW. IF ANYTHING...UNCERTAINTY
CONTINUES TO GROW REGARDING WHICH OF THESE PERIODS MIGHT BE
FAVORED FOR MORE WIDESPREAD PRECIPITATION COVERAGE...SO FOR NOW
MOST OF THESE CHANCES CONTINUE TO BE HELD DOWN IN THE 20-30
PERCENT RANGE. AS DISCUSSED OVER THE PAST 24 HOURS...MONDAY COULD
POTENTIALLY FEATURE SOME OF THE HIGHEST FIRE DANGER THE LOCAL AREA
HAS SEEN THIS SUMMER...AND THESE CONCERNS ARE OUTLINED IN GREATER
DETAIL IN THE SEPARATE FIRE WEATHER SECTION BELOW.
STARTING WITH MONDAY/MONDAY NIGHT...THE LATEST 00Z/06Z MODELS ARE
IN GOOD AGREEMENT ON THE BIG PICTURE ALOFT...WITH THE LOCAL AREA
EXPERIENCING SOUTHWESTERLY FLOW ALOFT AS THE CENTER OF THE
EXPANSIVE RIDGE AXIS CURRENTLY PARKED OVERHEAD CONTINUES TO DRIFT
FARTHER AWAY INTO THE SOUTHEAST STATES...AS A PROGRESSIVE
SHORTWAVE TROUGH TRANSLATES ALONG THE U.S./CANADA BORDER FROM A
CENTRAL POSITION OVER NORTHERN MT AT SUNRISE MONDAY...TO NORTHERN
MN BY SUNRISE TUESDAY. IN RESPONSE...A MODEST COLD FRONT WILL
DRIFT SOUTHEASTWARD INTO THE CENTRAL PLAINS. DURING THE DAYTIME
MONDAY...THE CWA WILL REMAIN JUST AHEAD OF THIS COLD FRONT...WHICH
IS FORECAST TO ALIGN FROM NORTHEAST TO TO NORTH CENTRAL NEB BY
LATE AFTERNOON...BEFORE SLOWLY INFILTRATING MUCH OF THE
NORTHERN/CENTRAL CWA MONDAY NIGHT. THE DAYTIME HOURS SHOULD BE
ANOTHER HOT ONE AREA-WIDE...AS SUSTAINED SOUTH-SOUTHWEST WINDS
PICK UP TO AT LEAST 15-20 MPH WITH GUSTS 25+ MPH IN MOST
AREAS...EXCEPT FOR A BIT LIGHTER SPEEDS POSSIBLE IN FAR NORTHWEST
COUNTIES IN CLOSET PROXIMITY TO THE APPROACHING TROUGH AXIS. WITH
DEEP MIXING FORECAST TO AVERAGE UP TO AROUND 750 MILLIBARS OVER
MUCH OF THE CWA...ANTICIPATE DEWPOINTS TO FALL WELL DOWN INTO THE
50S DURING THE AFTERNOON...WITH 40S IN SEVERAL SOUTHWESTERN
COUNTIES. IN THEORY...THIS SETUP SHOULD SET THE STAGE FOR SOME OF
THE HOTTEST READINGS OF THIS ENTIRE HOT STRETCH...ESPECIALLY IN
CENTRAL/NORTHEAST COUNTIES...BUT SOMEWHAT ODDLY MET/MAV GUIDANCE
SUGGESTS HIGHS MONDAY WOULD BE A TOUCH COOLER THAN THOSE TODAY.
DESPITE THIS...HAVE KEPT FORECAST HIGHS AT LEAST A FEW DEGREES
ABOVE A GUIDANCE BLEND IN MOST AREAS...WITH ALL BUT THE FAR
NORTHERN CWA AIMED TO TOP OUT SOMEWHERE IN THE 98-103 RANGE...WITH
THE HIGHER END OF THIS RANGE IN FAR SOUTHERN/SOUTHWEST COUNTIES.
DUE TO THE LOWER DEWPOINTS...HEAT INDEX VALUES IN MOST AREAS ONLY
AVERAGE 95-100 DEGREES. AS FOR STORM CHANCES...MODELS VARY ON HOW
AGGRESSIVELY CONVECTION MAY TRY TO SLIP INTO OUR FAR NORTHWEST
ZONES MONDAY EVENING/NIGHT...WITH SOME BRINGING THEM JUST IN WHILE
OTHERS KEEP THEM JUST OUTSIDE. GIVEN THE SLOWING NATURE OF THE
SURFACE FRONT...HAVE BACKED OFF MON NIGHT POPS TO ONLY ABOUT THE
NORTHWESTERN 1/4 OF THE CWA...WHILE THE VAST MAJORITY OF THE CWA
STAYS DRY. ALTHOUGH ANY MARGINAL SEVERE THREAT DURING THE LATE
AFTERNOON/EVENING SHOULD LARGELY TARGET THE SANDHILLS REGION JUST
TO OUR NORTHWEST...SUPPOSE A STRONG TO MARGINALLY SEVERE STORM OR
TWO CANNOT BE RULED OUT SLIPPING INTO OUR AREA...WITH THE MAIN
THREAT BEING GUSTY WINDS DUE TO HIGH CLOUD BASES IN THE DEEPLY-
MIXED AIRMASS NEAR THE FRONT. SEVERE PARAMETERS ARE NOT ALL THAT
IMPRESSIVE...WITH THE GFS SUGGESTING EARLY EVENING CAPE AVERAGING
WELL UNDER 1000 J/KG...ALTHOUGH DEEP LAYER SHEAR ISN/T ALL THAT
POOR AROUND 30-40 KNOTS.
TUESDAY/TUES NIGHT...THE NORTHERN MN SHORTWAVE TROUGH QUICKLY
SLIDES EAST INTO SOUTHEAST CANADA...AND ALTHOUGH THE CWA SEES A
PERIOD OF DECENT UPPER JET ENTRANCE REGION LIFT AND ASSOCIATED MID
LEVEL FRONTOGENESIS...THE MAIN FORCING STEADILY SLIDES AWAY TO THE
NORTHEAST...ALLOWING THE SURFACE FRONT TO LOSE STEAM AND GENERALLY
STALL OUT WITHIN OR NEAR THE SOUTHERN EDGE OF THE CWA BY TUESDAY
AFTERNOON/NIGHT. THERE COULD BE A DECENT TEMP GRADIENT IN HIGHS
TUESDAY AFTERNOON...AND HAVE MADE LITTLE CHANGE...STILL AIMING FOR
LOW-MID 80S NORTHWEST TO LOW-MID 90S SOUTHEAST. IF ENOUGH
INSTABILITY BUILDS ALONG THE SURFACE BOUNDARY...COULD MAYBE SEE
SOME STRONG TO SEVERE NEAR-SURFACE BASED STORMS FLARE UP IN
SOUTHERN COUNTIES TUESDAY AFTERNOON/EVENING...WITH MORE ELEVATED
ACTIVITY DEVELOPING FARTHER NORTH AS THE NIGHT WEARS ON IN RESPONSE
TO MID-LEVEL THETA-E ADVECTION. EVEN ONLY 3 DAYS
AWAY...UNCERTAINTY IS VERY HIGH HERE...AND HAVE KEPT DAYTIME POPS
IN SLIGHT CHANCE RANGE...WITH A GREATER COVERAGE OF 30 POPS
TUESDAY NIGHT.
WEDNESDAY THROUGH FRIDAY NIGHT...THERE CONTINUES MULTIPLE...MAINLY
20-30 PERCENT POPS ACROSS ALL/MOST OF THE CWA...AND OBVIOUSLY A
LOT OF FINE-TUNING WILL NEED DONE HERE IN THE COMING DAYS. ON THE
LARGE SCALE ALOFT...THE LOCAL AREA SETS UP UNDER FAIRLY WEAK WEST-
SOUTHWEST FLOW ALOFT...IN THE WAKE OF A DEEPENING TROUGH MIGRATING
ACROSS SOUTHEAST CANADA/THE NORTHEAST CONUS...AND ALONG THE
NORTHERN PERIPHERY OF AN EXPANSIVE SOUTHERN CONUS RIDGE
AXIS...WHICH INSTEAD OF BEING OVERHEAD AS THE CURRENT ONE
IS...THIS TIME SETS UP FARTHER SOUTH MORE OVER OK/TX. WITH THE
REMNANT...GENERALLY EAST-WEST SURFACE FRONT REMAINING IN PLACE
NEAR OR OVER THE CWA DURING THE TIME...AND WITH THE AREA BEING
PRONE TO MAINLY NOCTURNAL INCREASES IN THETA-E ADVECTION IN THE
850-700MB LAYER...THERE COULD BE SEVERAL ROUNDS OF
SHOWERS/STORMS...AND MAYBE EVEN AN OCCASIONAL SEVERE THREAT. TEMP-
WISE...LITTLE CHANGE FROM PREVIOUS WITH HIGHS GENERALLY LOW-MID
80S MOST AREAS...ALTHOUGH SOME 70S NOT OUT OF THE QUESTION.
SATURDAY...HAVE LEFT OUT POPS FOR NOW DUE TO INCREASING MODEL
VARIABILITY AND UNCERTAINTY AT THIS TIME RANGE..BUT DRY IS NO
GUARANTEE...WITH THE LOCAL AREA REMAINING NORTH OF THE SOUTHERN
PLAINS RIDGE AND POSSIBLY IN THE PATH OF SOME LOW AMPLITUDE
DISTURBANCES BRUSHING BY THROUGH THE NORTHERN PLAINS. WILL CALL
FOR MAINLY MID 80S IN NEB ZONES AND UPPER 80S IN KS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 536 AM CDT SUN SEP 8 2013
MAIN CONCERN FOR THE TAF PERIOD IS IFR/LIFR CIGS/VSBYS IN
FOG/STRATUS FOR A COUPLE OF HOURS THIS MORNING. CIGS AND VSBYS
WILL IMPROVE AFTER SUNRISE...WITH VFR CONDITIONS EXPECTED FOR THE
REMAINDER OF THE TAF PERIOD. THERE IS AN OUTSIDE CHC FOR AN
ISOLATED STORM LATE THIS AFTN/EVE BUT CHCS ARE NOT GREAT ENOUGH TO
INCLUDE ATTM. WINDS WILL TRANSITION SOUTHERLY AFTER A WARM FRONT
LIFTS NORTH OF KGRI.
&&
.FIRE WEATHER...
ISSUED AT 453 AM CDT SUN SEP 8 2013
AS PREVIOUSLY DISCUSSED OVER THE PAST 24 HOURS...MONDAY CONTINUES
TO APPEAR A DECENT CANDIDATE FOR NEAR-CRITICAL TO POTENTIALLY
CRITICAL FIRE DANGER ACROSS PARTS OF THE CWA. ON SATURDAY...AREA
FIRE WEATHER MANAGERS DEEMED VEGETATIVE FUELS ACROSS OUR KS ZONES
TO BE DRY ENOUGH TO SUPPORT POSSIBLE HEADLINES...ALTHOUGH FUELS
ACROSS OUR NEBRASKA COUNTIES ARE STILL ASSUMED TO BE GREEN ENOUGH
TO PRECLUDE MAJOR ISSUES BARRING FURTHER INFORMATION. AS LONG AS
FUELS ARE DEEMED FAVORABLE...CRITICAL FIRE WEATHER THRESHOLDS
ACROSS THE GID CWA INCLUDE A COMBINATION OF RELATIVE HUMIDITY
AT/BELOW 20 PERCENT AND SUSTAINED WINDS/GUSTS OF 20 MPH/25 MPH FOR
3+ HOURS. AS THE FORECAST CURRENTLY STANDS...A DECENT OVERLAP OF
THESE WIND/RH PARAMETERS IS ANTICIPATED ACROSS MUCH OF THE
SOUTHWESTERN HALF OF THE CWA MONDAY AFTERNOON...AS INCREASING
SOUTHWESTERLY WINDS ALLOW HOT...DRY AIR TO OVERSPREAD THE AREA.
EVEN IN NORTHEAST PORTIONS OF THE CWA...RH VALUES ARE FORECAST TO
DROP BETWEEN 21-30 PERCENT...SO THERE COULD BE AT LEAST SOME
DEGREE OF FIRE DANGER THERE AS WELL DESPITE THE OVERALL GREENER
FUELS. GIVEN THAT MONDAY AFTERNOON IS STILL 30+ HOURS AWAY AND
STILL SUBJECT TO SOME FINE-TUNING...AND AFTER COORDINATION WITH
SURROUNDING OFFICES...WILL HOLD OFF ON ANY FIRE WEATHER HEADLINES
FOR KS ZONES AT THIS TIME...BUT WILL CONTINUE TO ADVERTISE NEAR-
CRITICAL TO POTENTIALLY CRITICAL CONDITIONS IN THE HAZARDOUS
WEATHER OUTLOOK.
&&
.CLIMATE...
ISSUED AT 453 AM CDT SUN SEP 8 2013
ALTHOUGH CURRENT FORECAST HIGH TEMPERATURES TODAY/MONDAY AT OUR
PRIMARY CLIMATE RECORD SITES GRAND ISLAND/HASTINGS ARE CURRENTLY
FORECAST SLIGHTLY SHY OF RECORDS...IT COULD BE A PRETTY CLOSE
CALL. THOSE RECORDS ARE AS FOLLOWS...
SUNDAY SEP. 8...GRAND ISLAND 101 IN 1931 AND 1928
HASTINGS 101 IN 1931
MONDAY SEP. 9...GRAND ISLAND 104 IN 1931
HASTINGS 102 IN 1919
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ039>041-
046>048-060>063.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...FAY
LONG TERM...PFANNKUCH
AVIATION...FAY
FIRE WEATHER...PFANNKUCH
CLIMATE...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
908 AM CDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 908 AM CDT SUN SEP 8 2013
THE DENSE FOG ADVY HAS BEEN EXTENDED ONE MORE HOUR PER WEBCAMS...
AIRPORT VSBYS AND VIS SATELLITE. USING CONDITIONAL CLIMATOLOGY
/LOOKING BACK AT PAST SIMILAR EVENTS DURING AUG-SEP/ THE
PROBABILITY OF IFR CIG/VSBY CONTS VERY HIGH /81 PERCENT/ THRU 14Z
AND THEN DROPS TO 62 PERCENT 15Z AND 38 PERCENT BY 16Z.
SATELLITE SHOWS A DRY OUTFLOW BOUNDARY FROM OVERNGT TSTMS
APPROACHING NEB HWY 92. THIS WILL SHIFT WINDS TO NE AS ALREADY
SEEN AT ODX/BVN. THIS WILL COMPLICATE THE FCST HIGHS TODAY AND
DEPENDING ON ITS DENSITY IT MAY PREVENT THE E-W TROF FROM LIFTING
BACK N.
MRNG DATA DIAGNOSIS IS STILL ON-GOING...BUT ENVISION DWPTS WILL
NEED TO BE LOWERED SUBSTANTIALLY S AND W OF THE TRI-CITIES. HIGH
TEMPS IN THE 100S VIRTUALLY GUARANTEES MIN RH DROPPING INTO THE
TEENS THIS AFTN.
MORE LATER...
UPDATE ISSUED AT 706 AM CDT SUN SEP 8 2013
WITHIN THE PAST HOUR...DENSE FOG HAS EXPANDED IN COVERAGE EASTWARD
ACROSS MOST COUNTIES MAINLY ALONG/NORTH OF THE INTERSTATE 80
CORRIDOR PER AUTOMATED AIRPORT OBS AND WEBCAMS...WHILE
MAINTAINING INTENSITY FARTHER SOUTHWEST INTO THE HOLDREGE AREA AS
WELL. AS A RESULT...HAVE ADDED SEVERAL MORE COUNTIES TO THE DENSE
FOG ADVISORY...WHICH NOW INCLUDES GENERALLY ALL AREAS NORTH OF AN
ELWOOD-HASTINGS-YORK LINE. THE LATEST HRRR VISIBILITY PRODUCT HAS
CAPTURED THE AREA OF DENSE FOG FAIRLY WELL...AND SUGGESTS MOST OF
IT SHOULD LIFT/IMPROVE CONSIDERABLY BY 9 AM OR SO...BUT COULD
MAYBE LINGER CLOSER TO 10 AM IN THE CORE OF THE FOG AREA. INCOMING
DAY SHIFT WILL MONITOR TRENDS AND ADJUST HEADLINE AS NECESSARY.
UPDATE ISSUED AT 546 AM CDT SUN SEP 8 2013
WENT AHEAD WITH A DENSE FOG ADVISORY FOR A FEW HOURS THIS MORNING
FOR AREAS GENERALLY WEST OF HIGHWAY 281 AND ALONG THE INTERSTATE
80 CORRIDOR WHERE VSBY AVERAGE ONE QUARTER MILE OR LESS. VSBYS
WILL IMPROVE AFTER SUNRISE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 453 AM CDT SUN SEP 8 2013
AN UPPER LEVEL RIDGE OF HIGH PRESSURE CONTINUES TO DOMINATE THE
WEATHER PATTERN ACROSS THE INTERIOR CONUS...RESULTING IN HOT
TEMPERATURES FOR EARLY SEPTEMBER...WELL ABOVE NORMAL. AT THE
SURFACE...LOW PRESSURE WAS CENTERED ALONG THE WY/NEB BORDER...WITH
A STALLED FRONTAL BOUNDARY EXTENDING EASTWARD ALONG THE NEB/KS
STATELINE. HIGH DPS IN THE UPPER 60S TO AROUND 70 HAVE POOLED NORTH
OF THE BOUNDARY AND IN PRESENCE OF THE LLVL MOISTURE...SOME PATCHY
FOG HAS DEVELOPED WITH THE LOWEST VSBYS SO FAR AROUND ONE OR TWO
MILES. WILL CONTINUE TO MONITOR VSBY TRENDS THRU THE PRE DAWN
HOURS AS MODELS ARE NOT IN AGREEMENT ON HOW SIGNIFICANT FOG WILL BE
...AND THE HRRR SUGGESTS POTENTIAL FOR DENSE FOG.
THE FRONTAL BOUNDARY ALONG THE NEB/KS STATELINE WILL LIFT NORTH AS A
WARM FRONT TODAY AND TEMPERATURES WILL BE TOASTY WITH READINGS
RISING WELL INTO THE 90S...AND OUR WESTERN/SOUTHERN ZONES WILL BE
EVEN WARMER WITH HIGHS IN THE 100 TO 105F RANGE. HEAT INDICES WILL
BE FAIRLY CLOSE OR JUST BELOW AMBIENT TEMPS AS DPS LOWER BEHIND
BOUNDARY...AND SHOULD REMAIN SHY OF HEAT ADVISORY CRITERIA.
CANNOT COMPLETELY RULE OUT THE POTENTIAL FOR AN ISOLATED
THUNDERSTORM THIS AFTERNOON/EVENING...GENERALLY NORTH OF INTERSTATE
80 AS THE WARM FRONTAL BOUNDARY LIFTS ACROSS. MODELS INDICATE
PRESENCE OF MID LEVEL WAA AND FRONTOGENESIS BETWEEN H85 AND H7 NORTH
OF I-80 AND DAYTIME HIGHS ARE RIGHT AROUND CONVECTIVE TEMPERATURES.
BOTH THE NAM/GFS INDICATE THE LIFT/FORCING...BUT ONLY THE 4KM SPC
WRF INDICATES DEVELOPMENT. THE CONVECTIVE POTENTIAL IS LIMITED WITH
CAPPING/WARM MID LEVEL TEMPS...BUT CANNOT RULE OUT AN ISOLATED CHC
AND HAVE ADDED SMALL POPS.
DRY AND MILD CONDITIONS ARE FORECAST LATE EVENING ON...WITH LOWS
AVERAGING IN THE UPPER 60S TO AROUND 70F.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 453 AM CDT SUN SEP 8 2013
THERE CONTINUES TO REMAIN A FAIRLY CONSISTENT FORECAST THEME
THROUGH THESE 6 DAYS...WITH MONDAY FEATURING THE FINALE OF A
MEMORABLE EARLY SEPTEMBER HOT SPELL...ALTHOUGH TUESDAY STILL LOOKS
PLENTY TOASTY AS WELL ACROSS ROUGHLY THE SOUTHEASTERN 1/3 OF THE
CWA WITH HIGHS BETWEEN 90-95. THEREAFTER...THE WED-SAT TIME FRAME
IS EXPECTED TO FEATURE HIGHS PREDOMINANTLY IN THE 80S...WHICH ON
SEVERAL DAYS WILL STILL BE A FEW DEGREES ABOVE NORMAL DESPITE
BEING MORE SEASONABLE. AS FOR SHOWER/THUNDERSTORM CHANCES...THERE
REMAINS AT LEAST A SLIGHT CHANCE MENTION IN THE FORECAST FOR AT
LEAST A PORTION OF THE OUTLOOK AREA DURING EVERY PERIOD FROM
MONDAY NIGHT THROUGH FRIDAY NIGHT...WITH SATURDAY VOID OF
MENTIONABLE POPS...AT LEAST FOR NOW. IF ANYTHING...UNCERTAINTY
CONTINUES TO GROW REGARDING WHICH OF THESE PERIODS MIGHT BE
FAVORED FOR MORE WIDESPREAD PRECIPITATION COVERAGE...SO FOR NOW
MOST OF THESE CHANCES CONTINUE TO BE HELD DOWN IN THE 20-30
PERCENT RANGE. AS DISCUSSED OVER THE PAST 24 HOURS...MONDAY COULD
POTENTIALLY FEATURE SOME OF THE HIGHEST FIRE DANGER THE LOCAL AREA
HAS SEEN THIS SUMMER...AND THESE CONCERNS ARE OUTLINED IN GREATER
DETAIL IN THE SEPARATE FIRE WEATHER SECTION BELOW.
STARTING WITH MONDAY/MONDAY NIGHT...THE LATEST 00Z/06Z MODELS ARE
IN GOOD AGREEMENT ON THE BIG PICTURE ALOFT...WITH THE LOCAL AREA
EXPERIENCING SOUTHWESTERLY FLOW ALOFT AS THE CENTER OF THE
EXPANSIVE RIDGE AXIS CURRENTLY PARKED OVERHEAD CONTINUES TO DRIFT
FARTHER AWAY INTO THE SOUTHEAST STATES...AS A PROGRESSIVE
SHORTWAVE TROUGH TRANSLATES ALONG THE U.S./CANADA BORDER FROM A
CENTRAL POSITION OVER NORTHERN MT AT SUNRISE MONDAY...TO NORTHERN
MN BY SUNRISE TUESDAY. IN RESPONSE...A MODEST COLD FRONT WILL
DRIFT SOUTHEASTWARD INTO THE CENTRAL PLAINS. DURING THE DAYTIME
MONDAY...THE CWA WILL REMAIN JUST AHEAD OF THIS COLD FRONT...WHICH
IS FORECAST TO ALIGN FROM NORTHEAST TO TO NORTH CENTRAL NEB BY
LATE AFTERNOON...BEFORE SLOWLY INFILTRATING MUCH OF THE
NORTHERN/CENTRAL CWA MONDAY NIGHT. THE DAYTIME HOURS SHOULD BE
ANOTHER HOT ONE AREA-WIDE...AS SUSTAINED SOUTH-SOUTHWEST WINDS
PICK UP TO AT LEAST 15-20 MPH WITH GUSTS 25+ MPH IN MOST
AREAS...EXCEPT FOR A BIT LIGHTER SPEEDS POSSIBLE IN FAR NORTHWEST
COUNTIES IN CLOSET PROXIMITY TO THE APPROACHING TROUGH AXIS. WITH
DEEP MIXING FORECAST TO AVERAGE UP TO AROUND 750 MILLIBARS OVER
MUCH OF THE CWA...ANTICIPATE DEWPOINTS TO FALL WELL DOWN INTO THE
50S DURING THE AFTERNOON...WITH 40S IN SEVERAL SOUTHWESTERN
COUNTIES. IN THEORY...THIS SETUP SHOULD SET THE STAGE FOR SOME OF
THE HOTTEST READINGS OF THIS ENTIRE HOT STRETCH...ESPECIALLY IN
CENTRAL/NORTHEAST COUNTIES...BUT SOMEWHAT ODDLY MET/MAV GUIDANCE
SUGGESTS HIGHS MONDAY WOULD BE A TOUCH COOLER THAN THOSE TODAY.
DESPITE THIS...HAVE KEPT FORECAST HIGHS AT LEAST A FEW DEGREES
ABOVE A GUIDANCE BLEND IN MOST AREAS...WITH ALL BUT THE FAR
NORTHERN CWA AIMED TO TOP OUT SOMEWHERE IN THE 98-103 RANGE...WITH
THE HIGHER END OF THIS RANGE IN FAR SOUTHERN/SOUTHWEST COUNTIES.
DUE TO THE LOWER DEWPOINTS...HEAT INDEX VALUES IN MOST AREAS ONLY
AVERAGE 95-100 DEGREES. AS FOR STORM CHANCES...MODELS VARY ON HOW
AGGRESSIVELY CONVECTION MAY TRY TO SLIP INTO OUR FAR NORTHWEST
ZONES MONDAY EVENING/NIGHT...WITH SOME BRINGING THEM JUST IN WHILE
OTHERS KEEP THEM JUST OUTSIDE. GIVEN THE SLOWING NATURE OF THE
SURFACE FRONT...HAVE BACKED OFF MON NIGHT POPS TO ONLY ABOUT THE
NORTHWESTERN 1/4 OF THE CWA...WHILE THE VAST MAJORITY OF THE CWA
STAYS DRY. ALTHOUGH ANY MARGINAL SEVERE THREAT DURING THE LATE
AFTERNOON/EVENING SHOULD LARGELY TARGET THE SANDHILLS REGION JUST
TO OUR NORTHWEST...SUPPOSE A STRONG TO MARGINALLY SEVERE STORM OR
TWO CANNOT BE RULED OUT SLIPPING INTO OUR AREA...WITH THE MAIN
THREAT BEING GUSTY WINDS DUE TO HIGH CLOUD BASES IN THE DEEPLY-
MIXED AIRMASS NEAR THE FRONT. SEVERE PARAMETERS ARE NOT ALL THAT
IMPRESSIVE...WITH THE GFS SUGGESTING EARLY EVENING CAPE AVERAGING
WELL UNDER 1000 J/KG...ALTHOUGH DEEP LAYER SHEAR ISN/T ALL THAT
POOR AROUND 30-40 KNOTS.
TUESDAY/TUES NIGHT...THE NORTHERN MN SHORTWAVE TROUGH QUICKLY
SLIDES EAST INTO SOUTHEAST CANADA...AND ALTHOUGH THE CWA SEES A
PERIOD OF DECENT UPPER JET ENTRANCE REGION LIFT AND ASSOCIATED MID
LEVEL FRONTOGENESIS...THE MAIN FORCING STEADILY SLIDES AWAY TO THE
NORTHEAST...ALLOWING THE SURFACE FRONT TO LOSE STEAM AND GENERALLY
STALL OUT WITHIN OR NEAR THE SOUTHERN EDGE OF THE CWA BY TUESDAY
AFTERNOON/NIGHT. THERE COULD BE A DECENT TEMP GRADIENT IN HIGHS
TUESDAY AFTERNOON...AND HAVE MADE LITTLE CHANGE...STILL AIMING FOR
LOW-MID 80S NORTHWEST TO LOW-MID 90S SOUTHEAST. IF ENOUGH
INSTABILITY BUILDS ALONG THE SURFACE BOUNDARY...COULD MAYBE SEE
SOME STRONG TO SEVERE NEAR-SURFACE BASED STORMS FLARE UP IN
SOUTHERN COUNTIES TUESDAY AFTERNOON/EVENING...WITH MORE ELEVATED
ACTIVITY DEVELOPING FARTHER NORTH AS THE NIGHT WEARS ON IN RESPONSE
TO MID-LEVEL THETA-E ADVECTION. EVEN ONLY 3 DAYS
AWAY...UNCERTAINTY IS VERY HIGH HERE...AND HAVE KEPT DAYTIME POPS
IN SLIGHT CHANCE RANGE...WITH A GREATER COVERAGE OF 30 POPS
TUESDAY NIGHT.
WEDNESDAY THROUGH FRIDAY NIGHT...THERE CONTINUES MULTIPLE...MAINLY
20-30 PERCENT POPS ACROSS ALL/MOST OF THE CWA...AND OBVIOUSLY A
LOT OF FINE-TUNING WILL NEED DONE HERE IN THE COMING DAYS. ON THE
LARGE SCALE ALOFT...THE LOCAL AREA SETS UP UNDER FAIRLY WEAK WEST-
SOUTHWEST FLOW ALOFT...IN THE WAKE OF A DEEPENING TROUGH MIGRATING
ACROSS SOUTHEAST CANADA/THE NORTHEAST CONUS...AND ALONG THE
NORTHERN PERIPHERY OF AN EXPANSIVE SOUTHERN CONUS RIDGE
AXIS...WHICH INSTEAD OF BEING OVERHEAD AS THE CURRENT ONE
IS...THIS TIME SETS UP FARTHER SOUTH MORE OVER OK/TX. WITH THE
REMNANT...GENERALLY EAST-WEST SURFACE FRONT REMAINING IN PLACE
NEAR OR OVER THE CWA DURING THE TIME...AND WITH THE AREA BEING
PRONE TO MAINLY NOCTURNAL INCREASES IN THETA-E ADVECTION IN THE
850-700MB LAYER...THERE COULD BE SEVERAL ROUNDS OF
SHOWERS/STORMS...AND MAYBE EVEN AN OCCASIONAL SEVERE THREAT. TEMP-
WISE...LITTLE CHANGE FROM PREVIOUS WITH HIGHS GENERALLY LOW-MID
80S MOST AREAS...ALTHOUGH SOME 70S NOT OUT OF THE QUESTION.
SATURDAY...HAVE LEFT OUT POPS FOR NOW DUE TO INCREASING MODEL
VARIABILITY AND UNCERTAINTY AT THIS TIME RANGE..BUT DRY IS NO
GUARANTEE...WITH THE LOCAL AREA REMAINING NORTH OF THE SOUTHERN
PLAINS RIDGE AND POSSIBLY IN THE PATH OF SOME LOW AMPLITUDE
DISTURBANCES BRUSHING BY THROUGH THE NORTHERN PLAINS. WILL CALL
FOR MAINLY MID 80S IN NEB ZONES AND UPPER 80S IN KS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 536 AM CDT SUN SEP 8 2013
MAIN CONCERN FOR THE TAF PERIOD IS IFR/LIFR CIGS/VSBYS IN
FOG/STRATUS FOR A COUPLE OF HOURS THIS MORNING. CIGS AND VSBYS
WILL IMPROVE AFTER SUNRISE...WITH VFR CONDITIONS EXPECTED FOR THE
REMAINDER OF THE TAF PERIOD. THERE IS AN OUTSIDE CHC FOR AN
ISOLATED STORM LATE THIS AFTN/EVE BUT CHCS ARE NOT GREAT ENOUGH TO
INCLUDE ATTM. WINDS WILL TRANSITION SOUTHERLY AFTER A WARM FRONT
LIFTS NORTH OF KGRI.
&&
.FIRE WEATHER...
ISSUED AT 453 AM CDT SUN SEP 8 2013
AS PREVIOUSLY DISCUSSED OVER THE PAST 24 HOURS...MONDAY CONTINUES
TO APPEAR A DECENT CANDIDATE FOR NEAR-CRITICAL TO POTENTIALLY
CRITICAL FIRE DANGER ACROSS PARTS OF THE CWA. ON SATURDAY...AREA
FIRE WEATHER MANAGERS DEEMED VEGETATIVE FUELS ACROSS OUR KS ZONES
TO BE DRY ENOUGH TO SUPPORT POSSIBLE HEADLINES...ALTHOUGH FUELS
ACROSS OUR NEBRASKA COUNTIES ARE STILL ASSUMED TO BE GREEN ENOUGH
TO PRECLUDE MAJOR ISSUES BARRING FURTHER INFORMATION. AS LONG AS
FUELS ARE DEEMED FAVORABLE...CRITICAL FIRE WEATHER THRESHOLDS
ACROSS THE GID CWA INCLUDE A COMBINATION OF RELATIVE HUMIDITY
AT/BELOW 20 PERCENT AND SUSTAINED WINDS/GUSTS OF 20 MPH/25 MPH FOR
3+ HOURS. AS THE FORECAST CURRENTLY STANDS...A DECENT OVERLAP OF
THESE WIND/RH PARAMETERS IS ANTICIPATED ACROSS MUCH OF THE
SOUTHWESTERN HALF OF THE CWA MONDAY AFTERNOON...AS INCREASING
SOUTHWESTERLY WINDS ALLOW HOT...DRY AIR TO OVERSPREAD THE AREA.
EVEN IN NORTHEAST PORTIONS OF THE CWA...RH VALUES ARE FORECAST TO
DROP BETWEEN 21-30 PERCENT...SO THERE COULD BE AT LEAST SOME
DEGREE OF FIRE DANGER THERE AS WELL DESPITE THE OVERALL GREENER
FUELS. GIVEN THAT MONDAY AFTERNOON IS STILL 30+ HOURS AWAY AND
STILL SUBJECT TO SOME FINE-TUNING...AND AFTER COORDINATION WITH
SURROUNDING OFFICES...WILL HOLD OFF ON ANY FIRE WEATHER HEADLINES
FOR KS ZONES AT THIS TIME...BUT WILL CONTINUE TO ADVERTISE NEAR-
CRITICAL TO POTENTIALLY CRITICAL CONDITIONS IN THE HAZARDOUS
WEATHER OUTLOOK.
&&
.CLIMATE...
ISSUED AT 453 AM CDT SUN SEP 8 2013
ALTHOUGH CURRENT FORECAST HIGH TEMPERATURES TODAY/MONDAY AT OUR
PRIMARY CLIMATE RECORD SITES GRAND ISLAND/HASTINGS ARE CURRENTLY
FORECAST SLIGHTLY SHY OF RECORDS...IT COULD BE A PRETTY CLOSE
CALL. THOSE RECORDS ARE AS FOLLOWS...
SUNDAY SEP. 8...GRAND ISLAND 101 IN 1931 AND 1928
HASTINGS 101 IN 1931
MONDAY SEP. 9...GRAND ISLAND 104 IN 1931
HASTINGS 102 IN 1919
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ039>041-
046>048-060>063.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...FAY
LONG TERM...PFANNKUCH
AVIATION...FAY
FIRE WEATHER...PFANNKUCH
CLIMATE...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
707 AM CDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 706 AM CDT SUN SEP 8 2013
WITHIN THE PAST HOUR...DENSE FOG HAS EXPANDED IN COVERAGE EASTWARD
ACROSS MOST COUNTIES MAINLY ALONG/NORTH OF THE INTERSTATE 80
CORRIDOR PER AUTOMATED AIRPORT OBS AND WEBCAMS...WHILE
MAINTAINING INTENSITY FARTHER SOUTHWEST INTO THE HOLDREGE AREA AS
WELL. AS A RESULT...HAVE ADDED SEVERAL MORE COUNTIES TO THE DENSE
FOG ADVISORY...WHICH NOW INCLUDES GENERALLY ALL AREAS NORTH OF AN
ELWOOD-HASTINGS-YORK LINE. THE LATEST HRRR VISIBILITY PRODUCT HAS
CAPTURED THE AREA OF DENSE FOG FAIRLY WELL...AND SUGGESTS MOST OF
IT SHOULD LIFT/IMPROVE CONSIDERABLY BY 9 AM OR SO...BUT COULD
MAYBE LINGER CLOSER TO 10 AM IN THE CORE OF THE FOG AREA. INCOMING
DAY SHIFT WILL MONITOR TRENDS AND ADJUST HEADLINE AS NECESSARY.
UPDATE ISSUED AT 546 AM CDT SUN SEP 8 2013
WENT AHEAD WITH A DENSE FOG ADVISORY FOR A FEW HOURS THIS MORNING
FOR AREAS GENERALLY WEST OF HIGHWAY 281 AND ALONG THE INTERSTATE
80 CORRIDOR WHERE VSBY AVERAGE ONE QUARTER MILE OR LESS. VSBYS
WILL IMPROVE AFTER SUNRISE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 453 AM CDT SUN SEP 8 2013
AN UPPER LEVEL RIDGE OF HIGH PRESSURE CONTINUES TO DOMINATE THE
WEATHER PATTERN ACROSS THE INTERIOR CONUS...RESULTING IN HOT
TEMPERATURES FOR EARLY SEPTEMBER...WELL ABOVE NORMAL. AT THE
SURFACE...LOW PRESSURE WAS CENTERED ALONG THE WY/NEB BORDER...WITH
A STALLED FRONTAL BOUNDARY EXTENDING EASTWARD ALONG THE NEB/KS
STATELINE. HIGH DPS IN THE UPPER 60S TO AROUND 70 HAVE POOLED NORTH
OF THE BOUNDARY AND IN PRESENCE OF THE LLVL MOISTURE...SOME PATCHY
FOG HAS DEVELOPED WITH THE LOWEST VSBYS SO FAR AROUND ONE OR TWO
MILES. WILL CONTINUE TO MONITOR VSBY TRENDS THRU THE PRE DAWN
HOURS AS MODELS ARE NOT IN AGREEMENT ON HOW SIGNIFICANT FOG WILL BE
...AND THE HRRR SUGGESTS POTENTIAL FOR DENSE FOG.
THE FRONTAL BOUNDARY ALONG THE NEB/KS STATELINE WILL LIFT NORTH AS A
WARM FRONT TODAY AND TEMPERATURES WILL BE TOASTY WITH READINGS
RISING WELL INTO THE 90S...AND OUR WESTERN/SOUTHERN ZONES WILL BE
EVEN WARMER WITH HIGHS IN THE 100 TO 105F RANGE. HEAT INDICES WILL
BE FAIRLY CLOSE OR JUST BELOW AMBIENT TEMPS AS DPS LOWER BEHIND
BOUNDARY...AND SHOULD REMAIN SHY OF HEAT ADVISORY CRITERIA.
CANNOT COMPLETELY RULE OUT THE POTENTIAL FOR AN ISOLATED
THUNDERSTORM THIS AFTERNOON/EVENING...GENERALLY NORTH OF INTERSTATE
80 AS THE WARM FRONTAL BOUNDARY LIFTS ACROSS. MODELS INDICATE
PRESENCE OF MID LEVEL WAA AND FRONTOGENESIS BETWEEN H85 AND H7 NORTH
OF I-80 AND DAYTIME HIGHS ARE RIGHT AROUND CONVECTIVE TEMPERATURES.
BOTH THE NAM/GFS INDICATE THE LIFT/FORCING...BUT ONLY THE 4KM SPC
WRF INDICATES DEVELOPMENT. THE CONVECTIVE POTENTIAL IS LIMITED WITH
CAPPING/WARM MID LEVEL TEMPS...BUT CANNOT RULE OUT AN ISOLATED CHC
AND HAVE ADDED SMALL POPS.
DRY AND MILD CONDITIONS ARE FORECAST LATE EVENING ON...WITH LOWS
AVERAGING IN THE UPPER 60S TO AROUND 70F.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 453 AM CDT SUN SEP 8 2013
THERE CONTINUES TO REMAIN A FAIRLY CONSISTENT FORECAST THEME
THROUGH THESE 6 DAYS...WITH MONDAY FEATURING THE FINALE OF A
MEMORABLE EARLY SEPTEMBER HOT SPELL...ALTHOUGH TUESDAY STILL LOOKS
PLENTY TOASTY AS WELL ACROSS ROUGHLY THE SOUTHEASTERN 1/3 OF THE
CWA WITH HIGHS BETWEEN 90-95. THEREAFTER...THE WED-SAT TIME FRAME
IS EXPECTED TO FEATURE HIGHS PREDOMINANTLY IN THE 80S...WHICH ON
SEVERAL DAYS WILL STILL BE A FEW DEGREES ABOVE NORMAL DESPITE
BEING MORE SEASONABLE. AS FOR SHOWER/THUNDERSTORM CHANCES...THERE
REMAINS AT LEAST A SLIGHT CHANCE MENTION IN THE FORECAST FOR AT
LEAST A PORTION OF THE OUTLOOK AREA DURING EVERY PERIOD FROM
MONDAY NIGHT THROUGH FRIDAY NIGHT...WITH SATURDAY VOID OF
MENTIONABLE POPS...AT LEAST FOR NOW. IF ANYTHING...UNCERTAINTY
CONTINUES TO GROW REGARDING WHICH OF THESE PERIODS MIGHT BE
FAVORED FOR MORE WIDESPREAD PRECIPITATION COVERAGE...SO FOR NOW
MOST OF THESE CHANCES CONTINUE TO BE HELD DOWN IN THE 20-30
PERCENT RANGE. AS DISCUSSED OVER THE PAST 24 HOURS...MONDAY COULD
POTENTIALLY FEATURE SOME OF THE HIGHEST FIRE DANGER THE LOCAL AREA
HAS SEEN THIS SUMMER...AND THESE CONCERNS ARE OUTLINED IN GREATER
DETAIL IN THE SEPARATE FIRE WEATHER SECTION BELOW.
STARTING WITH MONDAY/MONDAY NIGHT...THE LATEST 00Z/06Z MODELS ARE
IN GOOD AGREEMENT ON THE BIG PICTURE ALOFT...WITH THE LOCAL AREA
EXPERIENCING SOUTHWESTERLY FLOW ALOFT AS THE CENTER OF THE
EXPANSIVE RIDGE AXIS CURRENTLY PARKED OVERHEAD CONTINUES TO DRIFT
FARTHER AWAY INTO THE SOUTHEAST STATES...AS A PROGRESSIVE
SHORTWAVE TROUGH TRANSLATES ALONG THE U.S./CANADA BORDER FROM A
CENTRAL POSITION OVER NORTHERN MT AT SUNRISE MONDAY...TO NORTHERN
MN BY SUNRISE TUESDAY. IN RESPONSE...A MODEST COLD FRONT WILL
DRIFT SOUTHEASTWARD INTO THE CENTRAL PLAINS. DURING THE DAYTIME
MONDAY...THE CWA WILL REMAIN JUST AHEAD OF THIS COLD FRONT...WHICH
IS FORECAST TO ALIGN FROM NORTHEAST TO TO NORTH CENTRAL NEB BY
LATE AFTERNOON...BEFORE SLOWLY INFILTRATING MUCH OF THE
NORTHERN/CENTRAL CWA MONDAY NIGHT. THE DAYTIME HOURS SHOULD BE
ANOTHER HOT ONE AREA-WIDE...AS SUSTAINED SOUTH-SOUTHWEST WINDS
PICK UP TO AT LEAST 15-20 MPH WITH GUSTS 25+ MPH IN MOST
AREAS...EXCEPT FOR A BIT LIGHTER SPEEDS POSSIBLE IN FAR NORTHWEST
COUNTIES IN CLOSET PROXIMITY TO THE APPROACHING TROUGH AXIS. WITH
DEEP MIXING FORECAST TO AVERAGE UP TO AROUND 750 MILLIBARS OVER
MUCH OF THE CWA...ANTICIPATE DEWPOINTS TO FALL WELL DOWN INTO THE
50S DURING THE AFTERNOON...WITH 40S IN SEVERAL SOUTHWESTERN
COUNTIES. IN THEORY...THIS SETUP SHOULD SET THE STAGE FOR SOME OF
THE HOTTEST READINGS OF THIS ENTIRE HOT STRETCH...ESPECIALLY IN
CENTRAL/NORTHEAST COUNTIES...BUT SOMEWHAT ODDLY MET/MAV GUIDANCE
SUGGESTS HIGHS MONDAY WOULD BE A TOUCH COOLER THAN THOSE TODAY.
DESPITE THIS...HAVE KEPT FORECAST HIGHS AT LEAST A FEW DEGREES
ABOVE A GUIDANCE BLEND IN MOST AREAS...WITH ALL BUT THE FAR
NORTHERN CWA AIMED TO TOP OUT SOMEWHERE IN THE 98-103 RANGE...WITH
THE HIGHER END OF THIS RANGE IN FAR SOUTHERN/SOUTHWEST COUNTIES.
DUE TO THE LOWER DEWPOINTS...HEAT INDEX VALUES IN MOST AREAS ONLY
AVERAGE 95-100 DEGREES. AS FOR STORM CHANCES...MODELS VARY ON HOW
AGGRESSIVELY CONVECTION MAY TRY TO SLIP INTO OUR FAR NORTHWEST
ZONES MONDAY EVENING/NIGHT...WITH SOME BRINGING THEM JUST IN WHILE
OTHERS KEEP THEM JUST OUTSIDE. GIVEN THE SLOWING NATURE OF THE
SURFACE FRONT...HAVE BACKED OFF MON NIGHT POPS TO ONLY ABOUT THE
NORTHWESTERN 1/4 OF THE CWA...WHILE THE VAST MAJORITY OF THE CWA
STAYS DRY. ALTHOUGH ANY MARGINAL SEVERE THREAT DURING THE LATE
AFTERNOON/EVENING SHOULD LARGELY TARGET THE SANDHILLS REGION JUST
TO OUR NORTHWEST...SUPPOSE A STRONG TO MARGINALLY SEVERE STORM OR
TWO CANNOT BE RULED OUT SLIPPING INTO OUR AREA...WITH THE MAIN
THREAT BEING GUSTY WINDS DUE TO HIGH CLOUD BASES IN THE DEEPLY-
MIXED AIRMASS NEAR THE FRONT. SEVERE PARAMETERS ARE NOT ALL THAT
IMPRESSIVE...WITH THE GFS SUGGESTING EARLY EVENING CAPE AVERAGING
WELL UNDER 1000 J/KG...ALTHOUGH DEEP LAYER SHEAR ISN/T ALL THAT
POOR AROUND 30-40 KNOTS.
TUESDAY/TUES NIGHT...THE NORTHERN MN SHORTWAVE TROUGH QUICKLY
SLIDES EAST INTO SOUTHEAST CANADA...AND ALTHOUGH THE CWA SEES A
PERIOD OF DECENT UPPER JET ENTRANCE REGION LIFT AND ASSOCIATED MID
LEVEL FRONTOGENESIS...THE MAIN FORCING STEADILY SLIDES AWAY TO THE
NORTHEAST...ALLOWING THE SURFACE FRONT TO LOSE STEAM AND GENERALLY
STALL OUT WITHIN OR NEAR THE SOUTHERN EDGE OF THE CWA BY TUESDAY
AFTERNOON/NIGHT. THERE COULD BE A DECENT TEMP GRADIENT IN HIGHS
TUESDAY AFTERNOON...AND HAVE MADE LITTLE CHANGE...STILL AIMING FOR
LOW-MID 80S NORTHWEST TO LOW-MID 90S SOUTHEAST. IF ENOUGH
INSTABILITY BUILDS ALONG THE SURFACE BOUNDARY...COULD MAYBE SEE
SOME STRONG TO SEVERE NEAR-SURFACE BASED STORMS FLARE UP IN
SOUTHERN COUNTIES TUESDAY AFTERNOON/EVENING...WITH MORE ELEVATED
ACTIVITY DEVELOPING FARTHER NORTH AS THE NIGHT WEARS ON IN RESPONSE
TO MID-LEVEL THETA-E ADVECTION. EVEN ONLY 3 DAYS
AWAY...UNCERTAINTY IS VERY HIGH HERE...AND HAVE KEPT DAYTIME POPS
IN SLIGHT CHANCE RANGE...WITH A GREATER COVERAGE OF 30 POPS
TUESDAY NIGHT.
WEDNESDAY THROUGH FRIDAY NIGHT...THERE CONTINUES MULTIPLE...MAINLY
20-30 PERCENT POPS ACROSS ALL/MOST OF THE CWA...AND OBVIOUSLY A
LOT OF FINE-TUNING WILL NEED DONE HERE IN THE COMING DAYS. ON THE
LARGE SCALE ALOFT...THE LOCAL AREA SETS UP UNDER FAIRLY WEAK WEST-
SOUTHWEST FLOW ALOFT...IN THE WAKE OF A DEEPENING TROUGH MIGRATING
ACROSS SOUTHEAST CANADA/THE NORTHEAST CONUS...AND ALONG THE
NORTHERN PERIPHERY OF AN EXPANSIVE SOUTHERN CONUS RIDGE
AXIS...WHICH INSTEAD OF BEING OVERHEAD AS THE CURRENT ONE
IS...THIS TIME SETS UP FARTHER SOUTH MORE OVER OK/TX. WITH THE
REMNANT...GENERALLY EAST-WEST SURFACE FRONT REMAINING IN PLACE
NEAR OR OVER THE CWA DURING THE TIME...AND WITH THE AREA BEING
PRONE TO MAINLY NOCTURNAL INCREASES IN THETA-E ADVECTION IN THE
850-700MB LAYER...THERE COULD BE SEVERAL ROUNDS OF
SHOWERS/STORMS...AND MAYBE EVEN AN OCCASIONAL SEVERE THREAT. TEMP-
WISE...LITTLE CHANGE FROM PREVIOUS WITH HIGHS GENERALLY LOW-MID
80S MOST AREAS...ALTHOUGH SOME 70S NOT OUT OF THE QUESTION.
SATURDAY...HAVE LEFT OUT POPS FOR NOW DUE TO INCREASING MODEL
VARIABILITY AND UNCERTAINTY AT THIS TIME RANGE..BUT DRY IS NO
GUARANTEE...WITH THE LOCAL AREA REMAINING NORTH OF THE SOUTHERN
PLAINS RIDGE AND POSSIBLY IN THE PATH OF SOME LOW AMPLITUDE
DISTURBANCES BRUSHING BY THROUGH THE NORTHERN PLAINS. WILL CALL
FOR MAINLY MID 80S IN NEB ZONES AND UPPER 80S IN KS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 536 AM CDT SUN SEP 8 2013
MAIN CONCERN FOR THE TAF PERIOD IS IFR/LIFR CIGS/VSBYS IN
FOG/STRATUS FOR A COUPLE OF HOURS THIS MORNING. CIGS AND VSBYS
WILL IMPROVE AFTER SUNRISE...WITH VFR CONDITIONS EXPECTED FOR THE
REMAINDER OF THE TAF PERIOD. THERE IS AN OUTSIDE CHC FOR AN
ISOLATED STORM LATE THIS AFTN/EVE BUT CHCS ARE NOT GREAT ENOUGH TO
INCLUDE ATTM. WINDS WILL TRANSITION SOUTHERLY AFTER A WARM FRONT
LIFTS NORTH OF KGRI.
&&
.FIRE WEATHER...
ISSUED AT 453 AM CDT SUN SEP 8 2013
AS PREVIOUSLY DISCUSSED OVER THE PAST 24 HOURS...MONDAY CONTINUES
TO APPEAR A DECENT CANDIDATE FOR NEAR-CRITICAL TO POTENTIALLY
CRITICAL FIRE DANGER ACROSS PARTS OF THE CWA. ON SATURDAY...AREA
FIRE WEATHER MANAGERS DEEMED VEGETATIVE FUELS ACROSS OUR KS ZONES
TO BE DRY ENOUGH TO SUPPORT POSSIBLE HEADLINES...ALTHOUGH FUELS
ACROSS OUR NEBRASKA COUNTIES ARE STILL ASSUMED TO BE GREEN ENOUGH
TO PRECLUDE MAJOR ISSUES BARRING FURTHER INFORMATION. AS LONG AS
FUELS ARE DEEMED FAVORABLE...CRITICAL FIRE WEATHER THRESHOLDS
ACROSS THE GID CWA INCLUDE A COMBINATION OF RELATIVE HUMIDITY
AT/BELOW 20 PERCENT AND SUSTAINED WINDS/GUSTS OF 20 MPH/25 MPH FOR
3+ HOURS. AS THE FORECAST CURRENTLY STANDS...A DECENT OVERLAP OF
THESE WIND/RH PARAMETERS IS ANTICIPATED ACROSS MUCH OF THE
SOUTHWESTERN HALF OF THE CWA MONDAY AFTERNOON...AS INCREASING
SOUTHWESTERLY WINDS ALLOW HOT...DRY AIR TO OVERSPREAD THE AREA.
EVEN IN NORTHEAST PORTIONS OF THE CWA...RH VALUES ARE FORECAST TO
DROP BETWEEN 21-30 PERCENT...SO THERE COULD BE AT LEAST SOME
DEGREE OF FIRE DANGER THERE AS WELL DESPITE THE OVERALL GREENER
FUELS. GIVEN THAT MONDAY AFTERNOON IS STILL 30+ HOURS AWAY AND
STILL SUBJECT TO SOME FINE-TUNING...AND AFTER COORDINATION WITH
SURROUNDING OFFICES...WILL HOLD OFF ON ANY FIRE WEATHER HEADLINES
FOR KS ZONES AT THIS TIME...BUT WILL CONTINUE TO ADVERTISE NEAR-
CRITICAL TO POTENTIALLY CRITICAL CONDITIONS IN THE HAZARDOUS
WEATHER OUTLOOK.
&&
.CLIMATE...
ISSUED AT 453 AM CDT SUN SEP 8 2013
ALTHOUGH CURRENT FORECAST HIGH TEMPERATURES TODAY/MONDAY AT OUR
PRIMARY CLIMATE RECORD SITES GRAND ISLAND/HASTINGS ARE CURRENTLY
FORECAST SLIGHTLY SHY OF RECORDS...IT COULD BE A PRETTY CLOSE
CALL. THOSE RECORDS ARE AS FOLLOWS...
SUNDAY SEP. 8...GRAND ISLAND 101 IN 1931 AND 1928
HASTINGS 101 IN 1931
MONDAY SEP. 9...GRAND ISLAND 104 IN 1931
HASTINGS 102 IN 1919
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR NEZ039>041-
046>049-060>064-072>075.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...FAY
LONG TERM...PFANNKUCH
AVIATION...FAY
FIRE WEATHER...PFANNKUCH
CLIMATE...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
548 AM CDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 546 AM CDT SUN SEP 8 2013
WENT AHEAD WITH A DENSE FOG ADVISORY FOR A FEW HOURS THIS MORNING
FOR AREAS GENERALLY WEST OF HIGHWAY 281 AND ALONG THE INTERSTATE
80 CORRIDOR WHERE VSBY AVERAGE ONE QUARTER MILE OR LESS. VSBYS
WILL IMPROVE AFTER SUNRISE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 453 AM CDT SUN SEP 8 2013
AN UPPER LEVEL RIDGE OF HIGH PRESSURE CONTINUES TO DOMINATE THE
WEATHER PATTERN ACROSS THE INTERIOR CONUS...RESULTING IN HOT
TEMPERATURES FOR EARLY SEPTEMBER...WELL ABOVE NORMAL. AT THE
SURFACE...LOW PRESSURE WAS CENTERED ALONG THE WY/NEB BORDER...WITH
A STALLED FRONTAL BOUNDARY EXTENDING EASTWARD ALONG THE NEB/KS
STATELINE. HIGH DPS IN THE UPPER 60S TO AROUND 70 HAVE POOLED NORTH
OF THE BOUNDARY AND IN PRESENCE OF THE LLVL MOISTURE...SOME PATCHY
FOG HAS DEVELOPED WITH THE LOWEST VSBYS SO FAR AROUND ONE OR TWO
MILES. WILL CONTINUE TO MONITOR VSBY TRENDS THRU THE PRE DAWN
HOURS AS MODELS ARE NOT IN AGREEMENT ON HOW SIGNIFICANT FOG WILL BE
...AND THE HRRR SUGGESTS POTENTIAL FOR DENSE FOG.
THE FRONTAL BOUNDARY ALONG THE NEB/KS STATELINE WILL LIFT NORTH AS A
WARM FRONT TODAY AND TEMPERATURES WILL BE TOASTY WITH READINGS
RISING WELL INTO THE 90S...AND OUR WESTERN/SOUTHERN ZONES WILL BE
EVEN WARMER WITH HIGHS IN THE 100 TO 105F RANGE. HEAT INDICES WILL
BE FAIRLY CLOSE OR JUST BELOW AMBIENT TEMPS AS DPS LOWER BEHIND
BOUNDARY...AND SHOULD REMAIN SHY OF HEAT ADVISORY CRITERIA.
CANNOT COMPLETELY RULE OUT THE POTENTIAL FOR AN ISOLATED
THUNDERSTORM THIS AFTERNOON/EVENING...GENERALLY NORTH OF INTERSTATE
80 AS THE WARM FRONTAL BOUNDARY LIFTS ACROSS. MODELS INDICATE
PRESENCE OF MID LEVEL WAA AND FRONTOGENESIS BETWEEN H85 AND H7 NORTH
OF I-80 AND DAYTIME HIGHS ARE RIGHT AROUND CONVECTIVE TEMPERATURES.
BOTH THE NAM/GFS INDICATE THE LIFT/FORCING...BUT ONLY THE 4KM SPC
WRF INDICATES DEVELOPMENT. THE CONVECTIVE POTENTIAL IS LIMITED WITH
CAPPING/WARM MID LEVEL TEMPS...BUT CANNOT RULE OUT AN ISOLATED CHC
AND HAVE ADDED SMALL POPS.
DRY AND MILD CONDITIONS ARE FORECAST LATE EVENING ON...WITH LOWS
AVERAGING IN THE UPPER 60S TO AROUND 70F.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 453 AM CDT SUN SEP 8 2013
THERE CONTINUES TO REMAIN A FAIRLY CONSISTENT FORECAST THEME
THROUGH THESE 6 DAYS...WITH MONDAY FEATURING THE FINALE OF A
MEMORABLE EARLY SEPTEMBER HOT SPELL...ALTHOUGH TUESDAY STILL LOOKS
PLENTY TOASTY AS WELL ACROSS ROUGHLY THE SOUTHEASTERN 1/3 OF THE
CWA WITH HIGHS BETWEEN 90-95. THEREAFTER...THE WED-SAT TIME FRAME
IS EXPECTED TO FEATURE HIGHS PREDOMINANTLY IN THE 80S...WHICH ON
SEVERAL DAYS WILL STILL BE A FEW DEGREES ABOVE NORMAL DESPITE
BEING MORE SEASONABLE. AS FOR SHOWER/THUNDERSTORM CHANCES...THERE
REMAINS AT LEAST A SLIGHT CHANCE MENTION IN THE FORECAST FOR AT
LEAST A PORTION OF THE OUTLOOK AREA DURING EVERY PERIOD FROM
MONDAY NIGHT THROUGH FRIDAY NIGHT...WITH SATURDAY VOID OF
MENTIONABLE POPS...AT LEAST FOR NOW. IF ANYTHING...UNCERTAINTY
CONTINUES TO GROW REGARDING WHICH OF THESE PERIODS MIGHT BE
FAVORED FOR MORE WIDESPREAD PRECIPITATION COVERAGE...SO FOR NOW
MOST OF THESE CHANCES CONTINUE TO BE HELD DOWN IN THE 20-30
PERCENT RANGE. AS DISCUSSED OVER THE PAST 24 HOURS...MONDAY COULD
POTENTIALLY FEATURE SOME OF THE HIGHEST FIRE DANGER THE LOCAL AREA
HAS SEEN THIS SUMMER...AND THESE CONCERNS ARE OUTLINED IN GREATER
DETAIL IN THE SEPARATE FIRE WEATHER SECTION BELOW.
STARTING WITH MONDAY/MONDAY NIGHT...THE LATEST 00Z/06Z MODELS ARE
IN GOOD AGREEMENT ON THE BIG PICTURE ALOFT...WITH THE LOCAL AREA
EXPERIENCING SOUTHWESTERLY FLOW ALOFT AS THE CENTER OF THE
EXPANSIVE RIDGE AXIS CURRENTLY PARKED OVERHEAD CONTINUES TO DRIFT
FARTHER AWAY INTO THE SOUTHEAST STATES...AS A PROGRESSIVE
SHORTWAVE TROUGH TRANSLATES ALONG THE U.S./CANADA BORDER FROM A
CENTRAL POSITION OVER NORTHERN MT AT SUNRISE MONDAY...TO NORTHERN
MN BY SUNRISE TUESDAY. IN RESPONSE...A MODEST COLD FRONT WILL
DRIFT SOUTHEASTWARD INTO THE CENTRAL PLAINS. DURING THE DAYTIME
MONDAY...THE CWA WILL REMAIN JUST AHEAD OF THIS COLD FRONT...WHICH
IS FORECAST TO ALIGN FROM NORTHEAST TO TO NORTH CENTRAL NEB BY
LATE AFTERNOON...BEFORE SLOWLY INFILTRATING MUCH OF THE
NORTHERN/CENTRAL CWA MONDAY NIGHT. THE DAYTIME HOURS SHOULD BE
ANOTHER HOT ONE AREA-WIDE...AS SUSTAINED SOUTH-SOUTHWEST WINDS
PICK UP TO AT LEAST 15-20 MPH WITH GUSTS 25+ MPH IN MOST
AREAS...EXCEPT FOR A BIT LIGHTER SPEEDS POSSIBLE IN FAR NORTHWEST
COUNTIES IN CLOSET PROXIMITY TO THE APPROACHING TROUGH AXIS. WITH
DEEP MIXING FORECAST TO AVERAGE UP TO AROUND 750 MILLIBARS OVER
MUCH OF THE CWA...ANTICIPATE DEWPOINTS TO FALL WELL DOWN INTO THE
50S DURING THE AFTERNOON...WITH 40S IN SEVERAL SOUTHWESTERN
COUNTIES. IN THEORY...THIS SETUP SHOULD SET THE STAGE FOR SOME OF
THE HOTTEST READINGS OF THIS ENTIRE HOT STRETCH...ESPECIALLY IN
CENTRAL/NORTHEAST COUNTIES...BUT SOMEWHAT ODDLY MET/MAV GUIDANCE
SUGGESTS HIGHS MONDAY WOULD BE A TOUCH COOLER THAN THOSE TODAY.
DESPITE THIS...HAVE KEPT FORECAST HIGHS AT LEAST A FEW DEGREES
ABOVE A GUIDANCE BLEND IN MOST AREAS...WITH ALL BUT THE FAR
NORTHERN CWA AIMED TO TOP OUT SOMEWHERE IN THE 98-103 RANGE...WITH
THE HIGHER END OF THIS RANGE IN FAR SOUTHERN/SOUTHWEST COUNTIES.
DUE TO THE LOWER DEWPOINTS...HEAT INDEX VALUES IN MOST AREAS ONLY
AVERAGE 95-100 DEGREES. AS FOR STORM CHANCES...MODELS VARY ON HOW
AGGRESSIVELY CONVECTION MAY TRY TO SLIP INTO OUR FAR NORTHWEST
ZONES MONDAY EVENING/NIGHT...WITH SOME BRINGING THEM JUST IN WHILE
OTHERS KEEP THEM JUST OUTSIDE. GIVEN THE SLOWING NATURE OF THE
SURFACE FRONT...HAVE BACKED OFF MON NIGHT POPS TO ONLY ABOUT THE
NORTHWESTERN 1/4 OF THE CWA...WHILE THE VAST MAJORITY OF THE CWA
STAYS DRY. ALTHOUGH ANY MARGINAL SEVERE THREAT DURING THE LATE
AFTERNOON/EVENING SHOULD LARGELY TARGET THE SANDHILLS REGION JUST
TO OUR NORTHWEST...SUPPOSE A STRONG TO MARGINALLY SEVERE STORM OR
TWO CANNOT BE RULED OUT SLIPPING INTO OUR AREA...WITH THE MAIN
THREAT BEING GUSTY WINDS DUE TO HIGH CLOUD BASES IN THE DEEPLY-
MIXED AIRMASS NEAR THE FRONT. SEVERE PARAMETERS ARE NOT ALL THAT
IMPRESSIVE...WITH THE GFS SUGGESTING EARLY EVENING CAPE AVERAGING
WELL UNDER 1000 J/KG...ALTHOUGH DEEP LAYER SHEAR ISN/T ALL THAT
POOR AROUND 30-40 KNOTS.
TUESDAY/TUES NIGHT...THE NORTHERN MN SHORTWAVE TROUGH QUICKLY
SLIDES EAST INTO SOUTHEAST CANADA...AND ALTHOUGH THE CWA SEES A
PERIOD OF DECENT UPPER JET ENTRANCE REGION LIFT AND ASSOCIATED MID
LEVEL FRONTOGENESIS...THE MAIN FORCING STEADILY SLIDES AWAY TO THE
NORTHEAST...ALLOWING THE SURFACE FRONT TO LOSE STEAM AND GENERALLY
STALL OUT WITHIN OR NEAR THE SOUTHERN EDGE OF THE CWA BY TUESDAY
AFTERNOON/NIGHT. THERE COULD BE A DECENT TEMP GRADIENT IN HIGHS
TUESDAY AFTERNOON...AND HAVE MADE LITTLE CHANGE...STILL AIMING FOR
LOW-MID 80S NORTHWEST TO LOW-MID 90S SOUTHEAST. IF ENOUGH
INSTABILITY BUILDS ALONG THE SURFACE BOUNDARY...COULD MAYBE SEE
SOME STRONG TO SEVERE NEAR-SURFACE BASED STORMS FLARE UP IN
SOUTHERN COUNTIES TUESDAY AFTERNOON/EVENING...WITH MORE ELEVATED
ACTIVITY DEVELOPING FARTHER NORTH AS THE NIGHT WEARS ON IN RESPONSE
TO MID-LEVEL THETA-E ADVECTION. EVEN ONLY 3 DAYS
AWAY...UNCERTAINTY IS VERY HIGH HERE...AND HAVE KEPT DAYTIME POPS
IN SLIGHT CHANCE RANGE...WITH A GREATER COVERAGE OF 30 POPS
TUESDAY NIGHT.
WEDNESDAY THROUGH FRIDAY NIGHT...THERE CONTINUES MULTIPLE...MAINLY
20-30 PERCENT POPS ACROSS ALL/MOST OF THE CWA...AND OBVIOUSLY A
LOT OF FINE-TUNING WILL NEED DONE HERE IN THE COMING DAYS. ON THE
LARGE SCALE ALOFT...THE LOCAL AREA SETS UP UNDER FAIRLY WEAK WEST-
SOUTHWEST FLOW ALOFT...IN THE WAKE OF A DEEPENING TROUGH MIGRATING
ACROSS SOUTHEAST CANADA/THE NORTHEAST CONUS...AND ALONG THE
NORTHERN PERIPHERY OF AN EXPANSIVE SOUTHERN CONUS RIDGE
AXIS...WHICH INSTEAD OF BEING OVERHEAD AS THE CURRENT ONE
IS...THIS TIME SETS UP FARTHER SOUTH MORE OVER OK/TX. WITH THE
REMNANT...GENERALLY EAST-WEST SURFACE FRONT REMAINING IN PLACE
NEAR OR OVER THE CWA DURING THE TIME...AND WITH THE AREA BEING
PRONE TO MAINLY NOCTURNAL INCREASES IN THETA-E ADVECTION IN THE
850-700MB LAYER...THERE COULD BE SEVERAL ROUNDS OF
SHOWERS/STORMS...AND MAYBE EVEN AN OCCASIONAL SEVERE THREAT. TEMP-
WISE...LITTLE CHANGE FROM PREVIOUS WITH HIGHS GENERALLY LOW-MID
80S MOST AREAS...ALTHOUGH SOME 70S NOT OUT OF THE QUESTION.
SATURDAY...HAVE LEFT OUT POPS FOR NOW DUE TO INCREASING MODEL
VARIABILITY AND UNCERTAINTY AT THIS TIME RANGE..BUT DRY IS NO
GUARANTEE...WITH THE LOCAL AREA REMAINING NORTH OF THE SOUTHERN
PLAINS RIDGE AND POSSIBLY IN THE PATH OF SOME LOW AMPLITUDE
DISTURBANCES BRUSHING BY THROUGH THE NORTHERN PLAINS. WILL CALL
FOR MAINLY MID 80S IN NEB ZONES AND UPPER 80S IN KS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 536 AM CDT SUN SEP 8 2013
MAIN CONCERN FOR THE TAF PERIOD IS IFR/LIFR CIGS/VSBYS IN
FOG/STRATUS FOR A COUPLE OF HOURS THIS MORNING. CIGS AND VSBYS
WILL IMPROVE AFTER SUNRISE...WITH VFR CONDITIONS EXPECTED FOR THE
REMAINDER OF THE TAF PERIOD. THERE IS AN OUTSIDE CHC FOR AN
ISOLATED STORM LATE THIS AFTN/EVE BUT CHCS ARE NOT GREAT ENOUGH TO
INCLUDE ATTM. WINDS WILL TRANSITION SOUTHERLY AFTER A WARM FRONT
LIFTS NORTH OF KGRI.
&&
.FIRE WEATHER...
ISSUED AT 453 AM CDT SUN SEP 8 2013
AS PREVIOUSLY DISCUSSED OVER THE PAST 24 HOURS...MONDAY CONTINUES
TO APPEAR A DECENT CANDIDATE FOR NEAR-CRITICAL TO POTENTIALLY
CRITICAL FIRE DANGER ACROSS PARTS OF THE CWA. ON SATURDAY...AREA
FIRE WEATHER MANAGERS DEEMED VEGETATIVE FUELS ACROSS OUR KS ZONES
TO BE DRY ENOUGH TO SUPPORT POSSIBLE HEADLINES...ALTHOUGH FUELS
ACROSS OUR NEBRASKA COUNTIES ARE STILL ASSUMED TO BE GREEN ENOUGH
TO PRECLUDE MAJOR ISSUES BARRING FURTHER INFORMATION. AS LONG AS
FUELS ARE DEEMED FAVORABLE...CRITICAL FIRE WEATHER THRESHOLDS
ACROSS THE GID CWA INCLUDE A COMBINATION OF RELATIVE HUMIDITY
AT/BELOW 20 PERCENT AND SUSTAINED WINDS/GUSTS OF 20 MPH/25 MPH FOR
3+ HOURS. AS THE FORECAST CURRENTLY STANDS...A DECENT OVERLAP OF
THESE WIND/RH PARAMETERS IS ANTICIPATED ACROSS MUCH OF THE
SOUTHWESTERN HALF OF THE CWA MONDAY AFTERNOON...AS INCREASING
SOUTHWESTERLY WINDS ALLOW HOT...DRY AIR TO OVERSPREAD THE AREA.
EVEN IN NORTHEAST PORTIONS OF THE CWA...RH VALUES ARE FORECAST TO
DROP BETWEEN 21-30 PERCENT...SO THERE COULD BE AT LEAST SOME
DEGREE OF FIRE DANGER THERE AS WELL DESPITE THE OVERALL GREENER
FUELS. GIVEN THAT MONDAY AFTERNOON IS STILL 30+ HOURS AWAY AND
STILL SUBJECT TO SOME FINE-TUNING...AND AFTER COORDINATION WITH
SURROUNDING OFFICES...WILL HOLD OFF ON ANY FIRE WEATHER HEADLINES
FOR KS ZONES AT THIS TIME...BUT WILL CONTINUE TO ADVERTISE NEAR-
CRITICAL TO POTENTIALLY CRITICAL CONDITIONS IN THE HAZARDOUS
WEATHER OUTLOOK.
&&
.CLIMATE...
ISSUED AT 453 AM CDT SUN SEP 8 2013
ALTHOUGH CURRENT FORECAST HIGH TEMPERATURES TODAY/MONDAY AT OUR
PRIMARY CLIMATE RECORD SITES GRAND ISLAND/HASTINGS ARE CURRENTLY
FORECAST SLIGHTLY SHY OF RECORDS...IT COULD BE A PRETTY CLOSE
CALL. THOSE RECORDS ARE AS FOLLOWS...
SUNDAY SEP. 8...GRAND ISLAND 101 IN 1931 AND 1928
HASTINGS 101 IN 1931
MONDAY SEP. 9...GRAND ISLAND 104 IN 1931
HASTINGS 102 IN 1919
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR NEZ046-060-
061-072>074.
KS...NONE.
&&
$$
UPDATE...FAY
SHORT TERM...FAY
LONG TERM...PFANNKUCH
AVIATION...FAY
FIRE WEATHER...PFANNKUCH
CLIMATE...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
540 AM CDT SUN SEP 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 453 AM CDT SUN SEP 8 2013
AN UPPER LEVEL RIDGE OF HIGH PRESSURE CONTINUES TO DOMINATE THE
WEATHER PATTERN ACROSS THE INTERIOR CONUS...RESULTING IN HOT
TEMPERATURES FOR EARLY SEPTEMBER...WELL ABOVE NORMAL. AT THE
SURFACE...LOW PRESSURE WAS CENTERED ALONG THE WY/NEB BORDER...WITH
A STALLED FRONTAL BOUNDARY EXTENDING EASTWARD ALONG THE NEB/KS
STATELINE. HIGH DPS IN THE UPPER 60S TO AROUND 70 HAVE POOLED NORTH
OF THE BOUNDARY AND IN PRESENCE OF THE LLVL MOISTURE...SOME PATCHY
FOG HAS DEVELOPED WITH THE LOWEST VSBYS SO FAR AROUND ONE OR TWO
MILES. WILL CONTINUE TO MONITOR VSBY TRENDS THRU THE PRE DAWN
HOURS AS MODELS ARE NOT IN AGREEMENT ON HOW SIGNIFICANT FOG WILL BE
...AND THE HRRR SUGGESTS POTENTIAL FOR DENSE FOG.
THE FRONTAL BOUNDARY ALONG THE NEB/KS STATELINE WILL LIFT NORTH AS A
WARM FRONT TODAY AND TEMPERATURES WILL BE TOASTY WITH READINGS
RISING WELL INTO THE 90S...AND OUR WESTERN/SOUTHERN ZONES WILL BE
EVEN WARMER WITH HIGHS IN THE 100 TO 105F RANGE. HEAT INDICES WILL
BE FAIRLY CLOSE OR JUST BELOW AMBIENT TEMPS AS DPS LOWER BEHIND
BOUNDARY...AND SHOULD REMAIN SHY OF HEAT ADVISORY CRITERIA.
CANNOT COMPLETELY RULE OUT THE POTENTIAL FOR AN ISOLATED
THUNDERSTORM THIS AFTERNOON/EVENING...GENERALLY NORTH OF INTERSTATE
80 AS THE WARM FRONTAL BOUNDARY LIFTS ACROSS. MODELS INDICATE
PRESENCE OF MID LEVEL WAA AND FRONTOGENESIS BETWEEN H85 AND H7 NORTH
OF I-80 AND DAYTIME HIGHS ARE RIGHT AROUND CONVECTIVE TEMPERATURES.
BOTH THE NAM/GFS INDICATE THE LIFT/FORCING...BUT ONLY THE 4KM SPC
WRF INDICATES DEVELOPMENT. THE CONVECTIVE POTENTIAL IS LIMITED WITH
CAPPING/WARM MID LEVEL TEMPS...BUT CANNOT RULE OUT AN ISOLATED CHC
AND HAVE ADDED SMALL POPS.
DRY AND MILD CONDITIONS ARE FORECAST LATE EVENING ON...WITH LOWS
AVERAGING IN THE UPPER 60S TO AROUND 70F.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 453 AM CDT SUN SEP 8 2013
THERE CONTINUES TO REMAIN A FAIRLY CONSISTENT FORECAST THEME
THROUGH THESE 6 DAYS...WITH MONDAY FEATURING THE FINALE OF A
MEMORABLE EARLY SEPTEMBER HOT SPELL...ALTHOUGH TUESDAY STILL LOOKS
PLENTY TOASTY AS WELL ACROSS ROUGHLY THE SOUTHEASTERN 1/3 OF THE
CWA WITH HIGHS BETWEEN 90-95. THEREAFTER...THE WED-SAT TIME FRAME
IS EXPECTED TO FEATURE HIGHS PREDOMINANTLY IN THE 80S...WHICH ON
SEVERAL DAYS WILL STILL BE A FEW DEGREES ABOVE NORMAL DESPITE
BEING MORE SEASONABLE. AS FOR SHOWER/THUNDERSTORM CHANCES...THERE
REMAINS AT LEAST A SLIGHT CHANCE MENTION IN THE FORECAST FOR AT
LEAST A PORTION OF THE OUTLOOK AREA DURING EVERY PERIOD FROM
MONDAY NIGHT THROUGH FRIDAY NIGHT...WITH SATURDAY VOID OF
MENTIONABLE POPS...AT LEAST FOR NOW. IF ANYTHING...UNCERTAINTY
CONTINUES TO GROW REGARDING WHICH OF THESE PERIODS MIGHT BE
FAVORED FOR MORE WIDESPREAD PRECIPITATION COVERAGE...SO FOR NOW
MOST OF THESE CHANCES CONTINUE TO BE HELD DOWN IN THE 20-30
PERCENT RANGE. AS DISCUSSED OVER THE PAST 24 HOURS...MONDAY COULD
POTENTIALLY FEATURE SOME OF THE HIGHEST FIRE DANGER THE LOCAL AREA
HAS SEEN THIS SUMMER...AND THESE CONCERNS ARE OUTLINED IN GREATER
DETAIL IN THE SEPARATE FIRE WEATHER SECTION BELOW.
STARTING WITH MONDAY/MONDAY NIGHT...THE LATEST 00Z/06Z MODELS ARE
IN GOOD AGREEMENT ON THE BIG PICTURE ALOFT...WITH THE LOCAL AREA
EXPERIENCING SOUTHWESTERLY FLOW ALOFT AS THE CENTER OF THE
EXPANSIVE RIDGE AXIS CURRENTLY PARKED OVERHEAD CONTINUES TO DRIFT
FARTHER AWAY INTO THE SOUTHEAST STATES...AS A PROGRESSIVE
SHORTWAVE TROUGH TRANSLATES ALONG THE U.S./CANADA BORDER FROM A
CENTRAL POSITION OVER NORTHERN MT AT SUNRISE MONDAY...TO NORTHERN
MN BY SUNRISE TUESDAY. IN RESPONSE...A MODEST COLD FRONT WILL
DRIFT SOUTHEASTWARD INTO THE CENTRAL PLAINS. DURING THE DAYTIME
MONDAY...THE CWA WILL REMAIN JUST AHEAD OF THIS COLD FRONT...WHICH
IS FORECAST TO ALIGN FROM NORTHEAST TO TO NORTH CENTRAL NEB BY
LATE AFTERNOON...BEFORE SLOWLY INFILTRATING MUCH OF THE
NORTHERN/CENTRAL CWA MONDAY NIGHT. THE DAYTIME HOURS SHOULD BE
ANOTHER HOT ONE AREA-WIDE...AS SUSTAINED SOUTH-SOUTHWEST WINDS
PICK UP TO AT LEAST 15-20 MPH WITH GUSTS 25+ MPH IN MOST
AREAS...EXCEPT FOR A BIT LIGHTER SPEEDS POSSIBLE IN FAR NORTHWEST
COUNTIES IN CLOSET PROXIMITY TO THE APPROACHING TROUGH AXIS. WITH
DEEP MIXING FORECAST TO AVERAGE UP TO AROUND 750 MILLIBARS OVER
MUCH OF THE CWA...ANTICIPATE DEWPOINTS TO FALL WELL DOWN INTO THE
50S DURING THE AFTERNOON...WITH 40S IN SEVERAL SOUTHWESTERN
COUNTIES. IN THEORY...THIS SETUP SHOULD SET THE STAGE FOR SOME OF
THE HOTTEST READINGS OF THIS ENTIRE HOT STRETCH...ESPECIALLY IN
CENTRAL/NORTHEAST COUNTIES...BUT SOMEWHAT ODDLY MET/MAV GUIDANCE
SUGGESTS HIGHS MONDAY WOULD BE A TOUCH COOLER THAN THOSE TODAY.
DESPITE THIS...HAVE KEPT FORECAST HIGHS AT LEAST A FEW DEGREES
ABOVE A GUIDANCE BLEND IN MOST AREAS...WITH ALL BUT THE FAR
NORTHERN CWA AIMED TO TOP OUT SOMEWHERE IN THE 98-103 RANGE...WITH
THE HIGHER END OF THIS RANGE IN FAR SOUTHERN/SOUTHWEST COUNTIES.
DUE TO THE LOWER DEWPOINTS...HEAT INDEX VALUES IN MOST AREAS ONLY
AVERAGE 95-100 DEGREES. AS FOR STORM CHANCES...MODELS VARY ON HOW
AGGRESSIVELY CONVECTION MAY TRY TO SLIP INTO OUR FAR NORTHWEST
ZONES MONDAY EVENING/NIGHT...WITH SOME BRINGING THEM JUST IN WHILE
OTHERS KEEP THEM JUST OUTSIDE. GIVEN THE SLOWING NATURE OF THE
SURFACE FRONT...HAVE BACKED OFF MON NIGHT POPS TO ONLY ABOUT THE
NORTHWESTERN 1/4 OF THE CWA...WHILE THE VAST MAJORITY OF THE CWA
STAYS DRY. ALTHOUGH ANY MARGINAL SEVERE THREAT DURING THE LATE
AFTERNOON/EVENING SHOULD LARGELY TARGET THE SANDHILLS REGION JUST
TO OUR NORTHWEST...SUPPOSE A STRONG TO MARGINALLY SEVERE STORM OR
TWO CANNOT BE RULED OUT SLIPPING INTO OUR AREA...WITH THE MAIN
THREAT BEING GUSTY WINDS DUE TO HIGH CLOUD BASES IN THE DEEPLY-
MIXED AIRMASS NEAR THE FRONT. SEVERE PARAMETERS ARE NOT ALL THAT
IMPRESSIVE...WITH THE GFS SUGGESTING EARLY EVENING CAPE AVERAGING
WELL UNDER 1000 J/KG...ALTHOUGH DEEP LAYER SHEAR ISN/T ALL THAT
POOR AROUND 30-40 KNOTS.
TUESDAY/TUES NIGHT...THE NORTHERN MN SHORTWAVE TROUGH QUICKLY
SLIDES EAST INTO SOUTHEAST CANADA...AND ALTHOUGH THE CWA SEES A
PERIOD OF DECENT UPPER JET ENTRANCE REGION LIFT AND ASSOCIATED MID
LEVEL FRONTOGENESIS...THE MAIN FORCING STEADILY SLIDES AWAY TO THE
NORTHEAST...ALLOWING THE SURFACE FRONT TO LOSE STEAM AND GENERALLY
STALL OUT WITHIN OR NEAR THE SOUTHERN EDGE OF THE CWA BY TUESDAY
AFTERNOON/NIGHT. THERE COULD BE A DECENT TEMP GRADIENT IN HIGHS
TUESDAY AFTERNOON...AND HAVE MADE LITTLE CHANGE...STILL AIMING FOR
LOW-MID 80S NORTHWEST TO LOW-MID 90S SOUTHEAST. IF ENOUGH
INSTABILITY BUILDS ALONG THE SURFACE BOUNDARY...COULD MAYBE SEE
SOME STRONG TO SEVERE NEAR-SURFACE BASED STORMS FLARE UP IN
SOUTHERN COUNTIES TUESDAY AFTERNOON/EVENING...WITH MORE ELEVATED
ACTIVITY DEVELOPING FARTHER NORTH AS THE NIGHT WEARS ON IN RESPONSE
TO MID-LEVEL THETA-E ADVECTION. EVEN ONLY 3 DAYS
AWAY...UNCERTAINTY IS VERY HIGH HERE...AND HAVE KEPT DAYTIME POPS
IN SLIGHT CHANCE RANGE...WITH A GREATER COVERAGE OF 30 POPS
TUESDAY NIGHT.
WEDNESDAY THROUGH FRIDAY NIGHT...THERE CONTINUES MULTIPLE...MAINLY
20-30 PERCENT POPS ACROSS ALL/MOST OF THE CWA...AND OBVIOUSLY A
LOT OF FINE-TUNING WILL NEED DONE HERE IN THE COMING DAYS. ON THE
LARGE SCALE ALOFT...THE LOCAL AREA SETS UP UNDER FAIRLY WEAK WEST-
SOUTHWEST FLOW ALOFT...IN THE WAKE OF A DEEPENING TROUGH MIGRATING
ACROSS SOUTHEAST CANADA/THE NORTHEAST CONUS...AND ALONG THE
NORTHERN PERIPHERY OF AN EXPANSIVE SOUTHERN CONUS RIDGE
AXIS...WHICH INSTEAD OF BEING OVERHEAD AS THE CURRENT ONE
IS...THIS TIME SETS UP FARTHER SOUTH MORE OVER OK/TX. WITH THE
REMNANT...GENERALLY EAST-WEST SURFACE FRONT REMAINING IN PLACE
NEAR OR OVER THE CWA DURING THE TIME...AND WITH THE AREA BEING
PRONE TO MAINLY NOCTURNAL INCREASES IN THETA-E ADVECTION IN THE
850-700MB LAYER...THERE COULD BE SEVERAL ROUNDS OF
SHOWERS/STORMS...AND MAYBE EVEN AN OCCASIONAL SEVERE THREAT. TEMP-
WISE...LITTLE CHANGE FROM PREVIOUS WITH HIGHS GENERALLY LOW-MID
80S MOST AREAS...ALTHOUGH SOME 70S NOT OUT OF THE QUESTION.
SATURDAY...HAVE LEFT OUT POPS FOR NOW DUE TO INCREASING MODEL
VARIABILITY AND UNCERTAINTY AT THIS TIME RANGE..BUT DRY IS NO
GUARANTEE...WITH THE LOCAL AREA REMAINING NORTH OF THE SOUTHERN
PLAINS RIDGE AND POSSIBLY IN THE PATH OF SOME LOW AMPLITUDE
DISTURBANCES BRUSHING BY THROUGH THE NORTHERN PLAINS. WILL CALL
FOR MAINLY MID 80S IN NEB ZONES AND UPPER 80S IN KS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 536 AM CDT SUN SEP 8 2013
MAIN CONCERN FOR THE TAF PERIOD IS IFR/LIFR CIGS/VSBYS IN
FOG/STRATUS FOR A COUPLE OF HOURS THIS MORNING. CIGS AND VSBYS
WILL IMPROVE AFTER SUNRISE...WITH VFR CONDITIONS EXPECTED FOR THE
REMAINDER OF THE TAF PERIOD. THERE IS AN OUTSIDE CHC FOR AN
ISOLATED STORM LATE THIS AFTN/EVE BUT CHCS ARE NOT GREAT ENOUGH TO
INCLUDE ATTM. WINDS WILL TRANSITION SOUTHERLY AFTER A WARM FRONT
LIFTS NORTH OF KGRI.
&&
.FIRE WEATHER...
ISSUED AT 453 AM CDT SUN SEP 8 2013
AS PREVIOUSLY DISCUSSED OVER THE PAST 24 HOURS...MONDAY CONTINUES
TO APPEAR A DECENT CANDIDATE FOR NEAR-CRITICAL TO POTENTIALLY
CRITICAL FIRE DANGER ACROSS PARTS OF THE CWA. ON SATURDAY...AREA
FIRE WEATHER MANAGERS DEEMED VEGETATIVE FUELS ACROSS OUR KS ZONES
TO BE DRY ENOUGH TO SUPPORT POSSIBLE HEADLINES...ALTHOUGH FUELS
ACROSS OUR NEBRASKA COUNTIES ARE STILL ASSUMED TO BE GREEN ENOUGH
TO PRECLUDE MAJOR ISSUES BARRING FURTHER INFORMATION. AS LONG AS
FUELS ARE DEEMED FAVORABLE...CRITICAL FIRE WEATHER THRESHOLDS
ACROSS THE GID CWA INCLUDE A COMBINATION OF RELATIVE HUMIDITY
AT/BELOW 20 PERCENT AND SUSTAINED WINDS/GUSTS OF 20 MPH/25 MPH FOR
3+ HOURS. AS THE FORECAST CURRENTLY STANDS...A DECENT OVERLAP OF
THESE WIND/RH PARAMETERS IS ANTICIPATED ACROSS MUCH OF THE
SOUTHWESTERN HALF OF THE CWA MONDAY AFTERNOON...AS INCREASING
SOUTHWESTERLY WINDS ALLOW HOT...DRY AIR TO OVERSPREAD THE AREA.
EVEN IN NORTHEAST PORTIONS OF THE CWA...RH VALUES ARE FORECAST TO
DROP BETWEEN 21-30 PERCENT...SO THERE COULD BE AT LEAST SOME
DEGREE OF FIRE DANGER THERE AS WELL DESPITE THE OVERALL GREENER
FUELS. GIVEN THAT MONDAY AFTERNOON IS STILL 30+ HOURS AWAY AND
STILL SUBJECT TO SOME FINE-TUNING...AND AFTER COORDINATION WITH
SURROUNDING OFFICES...WILL HOLD OFF ON ANY FIRE WEATHER HEADLINES
FOR KS ZONES AT THIS TIME...BUT WILL CONTINUE TO ADVERTISE NEAR-
CRITICAL TO POTENTIALLY CRITICAL CONDITIONS IN THE HAZARDOUS
WEATHER OUTLOOK.
&&
.CLIMATE...
ISSUED AT 453 AM CDT SUN SEP 8 2013
ALTHOUGH CURRENT FORECAST HIGH TEMPERATURES TODAY/MONDAY AT OUR
PRIMARY CLIMATE RECORD SITES GRAND ISLAND/HASTINGS ARE CURRENTLY
FORECAST SLIGHTLY SHY OF RECORDS...IT COULD BE A PRETTY CLOSE
CALL. THOSE RECORDS ARE AS FOLLOWS...
SUNDAY SEP. 8...GRAND ISLAND 101 IN 1931 AND 1928
HASTINGS 101 IN 1931
MONDAY SEP. 9...GRAND ISLAND 104 IN 1931
HASTINGS 102 IN 1919
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...FAY
LONG TERM...PFANNKUCH
AVIATION...FAY
FIRE WEATHER...PFANNKUCH
CLIMATE...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
453 AM CDT SUN SEP 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 453 AM CDT SUN SEP 8 2013
AN UPPER LEVEL RIDGE OF HIGH PRESSURE CONTINUES TO DOMINATE THE
WEATHER PATTERN ACROSS THE INTERIOR CONUS...RESULTING IN HOT
TEMPERATURES FOR EARLY SEPTEMBER...WELL ABOVE NORMAL. AT THE
SURFACE...LOW PRESSURE WAS CENTERED ALONG THE WY/NEB BORDER...WITH
A STALLED FRONTAL BOUNDARY EXTENDING EASTWARD ALONG THE NEB/KS
STATELINE. HIGH DPS IN THE UPPER 60S TO AROUND 70 HAVE POOLED NORTH
OF THE BOUNDARY AND IN PRESENCE OF THE LLVL MOISTURE...SOME PATCHY
FOG HAS DEVELOPED WITH THE LOWEST VSBYS SO FAR AROUND ONE OR TWO
MILES. WILL CONTINUE TO MONITOR VSBY TRENDS THRU THE PRE DAWN
HOURS AS MODELS ARE NOT IN AGREEMENT ON HOW SIGNIFICANT FOG WILL BE
...AND THE HRRR SUGGESTS POTENTIAL FOR DENSE FOG.
THE FRONTAL BOUNDARY ALONG THE NEB/KS STATELINE WILL LIFT NORTH AS A
WARM FRONT TODAY AND TEMPERATURES WILL BE TOASTY WITH READINGS
RISING WELL INTO THE 90S...AND OUR WESTERN/SOUTHERN ZONES WILL BE
EVEN WARMER WITH HIGHS IN THE 100 TO 105F RANGE. HEAT INDICES WILL
BE FAIRLY CLOSE OR JUST BELOW AMBIENT TEMPS AS DPS LOWER BEHIND
BOUNDARY...AND SHOULD REMAIN SHY OF HEAT ADVISORY CRITERIA.
CANNOT COMPLETELY RULE OUT THE POTENTIAL FOR AN ISOLATED
THUNDERSTORM THIS AFTERNOON/EVENING...GENERALLY NORTH OF INTERSTATE
80 AS THE WARM FRONTAL BOUNDARY LIFTS ACROSS. MODELS INDICATE
PRESENCE OF MID LEVEL WAA AND FRONTOGENESIS BETWEEN H85 AND H7 NORTH
OF I-80 AND DAYTIME HIGHS ARE RIGHT AROUND CONVECTIVE TEMPERATURES.
BOTH THE NAM/GFS INDICATE THE LIFT/FORCING...BUT ONLY THE 4KM SPC
WRF INDICATES DEVELOPMENT. THE CONVECTIVE POTENTIAL IS LIMITED WITH
CAPPING/WARM MID LEVEL TEMPS...BUT CANNOT RULE OUT AN ISOLATED CHC
AND HAVE ADDED SMALL POPS.
DRY AND MILD CONDITIONS ARE FORECAST LATE EVENING ON...WITH LOWS
AVERAGING IN THE UPPER 60S TO AROUND 70F.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 453 AM CDT SUN SEP 8 2013
THERE CONTINUES TO REMAIN A FAIRLY CONSISTENT FORECAST THEME
THROUGH THESE 6 DAYS...WITH MONDAY FEATURING THE FINALE OF A
MEMORABLE EARLY SEPTEMBER HOT SPELL...ALTHOUGH TUESDAY STILL LOOKS
PLENTY TOASTY AS WELL ACROSS ROUGHLY THE SOUTHEASTERN 1/3 OF THE
CWA WITH HIGHS BETWEEN 90-95. THEREAFTER...THE WED-SAT TIME FRAME
IS EXPECTED TO FEATURE HIGHS PREDOMINANTLY IN THE 80S...WHICH ON
SEVERAL DAYS WILL STILL BE A FEW DEGREES ABOVE NORMAL DESPITE
BEING MORE SEASONABLE. AS FOR SHOWER/THUNDERSTORM CHANCES...THERE
REMAINS AT LEAST A SLIGHT CHANCE MENTION IN THE FORECAST FOR AT
LEAST A PORTION OF THE OUTLOOK AREA DURING EVERY PERIOD FROM
MONDAY NIGHT THROUGH FRIDAY NIGHT...WITH SATURDAY VOID OF
MENTIONABLE POPS...AT LEAST FOR NOW. IF ANYTHING...UNCERTAINTY
CONTINUES TO GROW REGARDING WHICH OF THESE PERIODS MIGHT BE
FAVORED FOR MORE WIDESPREAD PRECIPITATION COVERAGE...SO FOR NOW
MOST OF THESE CHANCES CONTINUE TO BE HELD DOWN IN THE 20-30
PERCENT RANGE. AS DISCUSSED OVER THE PAST 24 HOURS...MONDAY COULD
POTENTIALLY FEATURE SOME OF THE HIGHEST FIRE DANGER THE LOCAL AREA
HAS SEEN THIS SUMMER...AND THESE CONCERNS ARE OUTLINED IN GREATER
DETAIL IN THE SEPARATE FIRE WEATHER SECTION BELOW.
STARTING WITH MONDAY/MONDAY NIGHT...THE LATEST 00Z/06Z MODELS ARE
IN GOOD AGREEMENT ON THE BIG PICTURE ALOFT...WITH THE LOCAL AREA
EXPERIENCING SOUTHWESTERLY FLOW ALOFT AS THE CENTER OF THE
EXPANSIVE RIDGE AXIS CURRENTLY PARKED OVERHEAD CONTINUES TO DRIFT
FARTHER AWAY INTO THE SOUTHEAST STATES...AS A PROGRESSIVE
SHORTWAVE TROUGH TRANSLATES ALONG THE U.S./CANADA BORDER FROM A
CENTRAL POSITION OVER NORTHERN MT AT SUNRISE MONDAY...TO NORTHERN
MN BY SUNRISE TUESDAY. IN RESPONSE...A MODEST COLD FRONT WILL
DRIFT SOUTHEASTWARD INTO THE CENTRAL PLAINS. DURING THE DAYTIME
MONDAY...THE CWA WILL REMAIN JUST AHEAD OF THIS COLD FRONT...WHICH
IS FORECAST TO ALIGN FROM NORTHEAST TO TO NORTH CENTRAL NEB BY
LATE AFTERNOON...BEFORE SLOWLY INFILTRATING MUCH OF THE
NORTHERN/CENTRAL CWA MONDAY NIGHT. THE DAYTIME HOURS SHOULD BE
ANOTHER HOT ONE AREA-WIDE...AS SUSTAINED SOUTH-SOUTHWEST WINDS
PICK UP TO AT LEAST 15-20 MPH WITH GUSTS 25+ MPH IN MOST
AREAS...EXCEPT FOR A BIT LIGHTER SPEEDS POSSIBLE IN FAR NORTHWEST
COUNTIES IN CLOSET PROXIMITY TO THE APPROACHING TROUGH AXIS. WITH
DEEP MIXING FORECAST TO AVERAGE UP TO AROUND 750 MILLIBARS OVER
MUCH OF THE CWA...ANTICIPATE DEWPOINTS TO FALL WELL DOWN INTO THE
50S DURING THE AFTERNOON...WITH 40S IN SEVERAL SOUTHWESTERN
COUNTIES. IN THEORY...THIS SETUP SHOULD SET THE STAGE FOR SOME OF
THE HOTTEST READINGS OF THIS ENTIRE HOT STRETCH...ESPECIALLY IN
CENTRAL/NORTHEAST COUNTIES...BUT SOMEWHAT ODDLY MET/MAV GUIDANCE
SUGGESTS HIGHS MONDAY WOULD BE A TOUCH COOLER THAN THOSE TODAY.
DESPITE THIS...HAVE KEPT FORECAST HIGHS AT LEAST A FEW DEGREES
ABOVE A GUIDANCE BLEND IN MOST AREAS...WITH ALL BUT THE FAR
NORTHERN CWA AIMED TO TOP OUT SOMEWHERE IN THE 98-103 RANGE...WITH
THE HIGHER END OF THIS RANGE IN FAR SOUTHERN/SOUTHWEST COUNTIES.
DUE TO THE LOWER DEWPOINTS...HEAT INDEX VALUES IN MOST AREAS ONLY
AVERAGE 95-100 DEGREES. AS FOR STORM CHANCES...MODELS VARY ON HOW
AGGRESSIVELY CONVECTION MAY TRY TO SLIP INTO OUR FAR NORTHWEST
ZONES MONDAY EVENING/NIGHT...WITH SOME BRINGING THEM JUST IN WHILE
OTHERS KEEP THEM JUST OUTSIDE. GIVEN THE SLOWING NATURE OF THE
SURFACE FRONT...HAVE BACKED OFF MON NIGHT POPS TO ONLY ABOUT THE
NORTHWESTERN 1/4 OF THE CWA...WHILE THE VAST MAJORITY OF THE CWA
STAYS DRY. ALTHOUGH ANY MARGINAL SEVERE THREAT DURING THE LATE
AFTERNOON/EVENING SHOULD LARGELY TARGET THE SANDHILLS REGION JUST
TO OUR NORTHWEST...SUPPOSE A STRONG TO MARGINALLY SEVERE STORM OR
TWO CANNOT BE RULED OUT SLIPPING INTO OUR AREA...WITH THE MAIN
THREAT BEING GUSTY WINDS DUE TO HIGH CLOUD BASES IN THE DEEPLY-
MIXED AIRMASS NEAR THE FRONT. SEVERE PARAMETERS ARE NOT ALL THAT
IMPRESSIVE...WITH THE GFS SUGGESTING EARLY EVENING CAPE AVERAGING
WELL UNDER 1000 J/KG...ALTHOUGH DEEP LAYER SHEAR ISN/T ALL THAT
POOR AROUND 30-40 KNOTS.
TUESDAY/TUES NIGHT...THE NORTHERN MN SHORTWAVE TROUGH QUICKLY
SLIDES EAST INTO SOUTHEAST CANADA...AND ALTHOUGH THE CWA SEES A
PERIOD OF DECENT UPPER JET ENTRANCE REGION LIFT AND ASSOCIATED MID
LEVEL FRONTOGENESIS...THE MAIN FORCING STEADILY SLIDES AWAY TO THE
NORTHEAST...ALLOWING THE SURFACE FRONT TO LOSE STEAM AND GENERALLY
STALL OUT WITHIN OR NEAR THE SOUTHERN EDGE OF THE CWA BY TUESDAY
AFTERNOON/NIGHT. THERE COULD BE A DECENT TEMP GRADIENT IN HIGHS
TUESDAY AFTERNOON...AND HAVE MADE LITTLE CHANGE...STILL AIMING FOR
LOW-MID 80S NORTHWEST TO LOW-MID 90S SOUTHEAST. IF ENOUGH
INSTABILITY BUILDS ALONG THE SURFACE BOUNDARY...COULD MAYBE SEE
SOME STRONG TO SEVERE NEAR-SURFACE BASED STORMS FLARE UP IN
SOUTHERN COUNTIES TUESDAY AFTERNOON/EVENING...WITH MORE ELEVATED
ACTIVITY DEVELOPING FARTHER NORTH AS THE NIGHT WEARS ON IN RESPONSE
TO MID-LEVEL THETA-E ADVECTION. EVEN ONLY 3 DAYS
AWAY...UNCERTAINTY IS VERY HIGH HERE...AND HAVE KEPT DAYTIME POPS
IN SLIGHT CHANCE RANGE...WITH A GREATER COVERAGE OF 30 POPS
TUESDAY NIGHT.
WEDNESDAY THROUGH FRIDAY NIGHT...THERE CONTINUES MULTIPLE...MAINLY
20-30 PERCENT POPS ACROSS ALL/MOST OF THE CWA...AND OBVIOUSLY A
LOT OF FINE-TUNING WILL NEED DONE HERE IN THE COMING DAYS. ON THE
LARGE SCALE ALOFT...THE LOCAL AREA SETS UP UNDER FAIRLY WEAK WEST-
SOUTHWEST FLOW ALOFT...IN THE WAKE OF A DEEPENING TROUGH MIGRATING
ACROSS SOUTHEAST CANADA/THE NORTHEAST CONUS...AND ALONG THE
NORTHERN PERIPHERY OF AN EXPANSIVE SOUTHERN CONUS RIDGE
AXIS...WHICH INSTEAD OF BEING OVERHEAD AS THE CURRENT ONE
IS...THIS TIME SETS UP FARTHER SOUTH MORE OVER OK/TX. WITH THE
REMNANT...GENERALLY EAST-WEST SURFACE FRONT REMAINING IN PLACE
NEAR OR OVER THE CWA DURING THE TIME...AND WITH THE AREA BEING
PRONE TO MAINLY NOCTURNAL INCREASES IN THETA-E ADVECTION IN THE
850-700MB LAYER...THERE COULD BE SEVERAL ROUNDS OF
SHOWERS/STORMS...AND MAYBE EVEN AN OCCASIONAL SEVERE THREAT. TEMP-
WISE...LITTLE CHANGE FROM PREVIOUS WITH HIGHS GENERALLY LOW-MID
80S MOST AREAS...ALTHOUGH SOME 70S NOT OUT OF THE QUESTION.
SATURDAY...HAVE LEFT OUT POPS FOR NOW DUE TO INCREASING MODEL
VARIABILITY AND UNCERTAINTY AT THIS TIME RANGE..BUT DRY IS NO
GUARANTEE...WITH THE LOCAL AREA REMAINING NORTH OF THE SOUTHERN
PLAINS RIDGE AND POSSIBLY IN THE PATH OF SOME LOW AMPLITUDE
DISTURBANCES BRUSHING BY THROUGH THE NORTHERN PLAINS. WILL CALL
FOR MAINLY MID 80S IN NEB ZONES AND UPPER 80S IN KS.
&&
.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1231 AM CDT SUN SEP 8 2013
A FRONTAL BOUNDARY HAS STALLED SOUTH OF THE TERMINAL AND AS
MOISTURE POOLS IN THE VICINITY OF THE BOUNDARY...THERE IS AN
OUTSIDE CHANCE FOR AN MVFR VSBY IN BR DURING THE PRE DAWN HOURS.
HAVE KEPT VSBYS AT VFR FOR NOW...BUT WILL MONITOR. THE FRONT WILL
LIFT TO THE NORTH AS WARM FRONT DURING THE DAY ON SUNDAY...WITH
THE CURRENT LIGHT AND VARIABLE WINDS BECOMING SOUTHERLY DURING THE
AFTN. CLOUDS ARE EXPECTED TO REMAIN AT VFR LEVELS.
&&
.FIRE WEATHER...
ISSUED AT 453 AM CDT SUN SEP 8 2013
AS PREVIOUSLY DISCUSSED OVER THE PAST 24 HOURS...MONDAY CONTINUES
TO APPEAR A DECENT CANDIDATE FOR NEAR-CRITICAL TO POTENTIALLY
CRITICAL FIRE DANGER ACROSS PARTS OF THE CWA. ON SATURDAY...AREA
FIRE WEATHER MANAGERS DEEMED VEGETATIVE FUELS ACROSS OUR KS ZONES
TO BE DRY ENOUGH TO SUPPORT POSSIBLE HEADLINES...ALTHOUGH FUELS
ACROSS OUR NEBRASKA COUNTIES ARE STILL ASSUMED TO BE GREEN ENOUGH
TO PRECLUDE MAJOR ISSUES BARRING FURTHER INFORMATION. AS LONG AS
FUELS ARE DEEMED FAVORABLE...CRITICAL FIRE WEATHER THRESHOLDS
ACROSS THE GID CWA INCLUDE A COMBINATION OF RELATIVE HUMIDITY
AT/BELOW 20 PERCENT AND SUSTAINED WINDS/GUSTS OF 20 MPH/25 MPH FOR
3+ HOURS. AS THE FORECAST CURRENTLY STANDS...A DECENT OVERLAP OF
THESE WIND/RH PARAMETERS IS ANTICIPATED ACROSS MUCH OF THE
SOUTHWESTERN HALF OF THE CWA MONDAY AFTERNOON...AS INCREASING
SOUTHWESTERLY WINDS ALLOW HOT...DRY AIR TO OVERSPREAD THE AREA.
EVEN IN NORTHEAST PORTIONS OF THE CWA...RH VALUES ARE FORECAST TO
DROP BETWEEN 21-30 PERCENT...SO THERE COULD BE AT LEAST SOME
DEGREE OF FIRE DANGER THERE AS WELL DESPITE THE OVERALL GREENER
FUELS. GIVEN THAT MONDAY AFTERNOON IS STILL 30+ HOURS AWAY AND
STILL SUBJECT TO SOME FINE-TUNING...AND AFTER COORDINATION WITH
SURROUNDING OFFICES...WILL HOLD OFF ON ANY FIRE WEATHER HEADLINES
FOR KS ZONES AT THIS TIME...BUT WILL CONTINUE TO ADVERTISE NEAR-
CRITICAL TO POTENTIALLY CRITICAL CONDITIONS IN THE HAZARDOUS
WEATHER OUTLOOK.
&&
.CLIMATE...
ISSUED AT 453 AM CDT SUN SEP 8 2013
ALTHOUGH CURRENT FORECAST HIGH TEMPERATURES TODAY/MONDAY AT OUR
PRIMARY CLIMATE RECORD SITES GRAND ISLAND/HASTINGS ARE CURRENTLY
FORECAST SLIGHTLY SHY OF RECORDS...IT COULD BE A PRETTY CLOSE
CALL. THOSE RECORDS ARE AS FOLLOWS...
SUNDAY SEP. 8...GRAND ISLAND 101 IN 1931 AND 1928
HASTINGS 101 IN 1931
MONDAY SEP. 9...GRAND ISLAND 104 IN 1931
HASTINGS 102 IN 1919
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...FAY
LONG TERM...PFANNKUCH
AVIATION...FAY
FIRE WEATHER...PFANNKUCH
CLIMATE...PFANNKUCH
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1113 PM CDT SAT SEP 7 2013
.SYNOPSIS...
ISSUED AT 319 PM CDT SAT SEP 7 2013
H5 ANALYSIS THIS MORNING HAS LOW PRESSURE CENTERED OVER
EASTERN WASHINGTON STATE WITH HIGH PRESSURE OVER NWRN KS. RIDGING
EXTENDED NORTH OF THIS HIGH INTO THE DAKOTAS. TROUGHING CONTINUED
ACROSS EASTERN CANADA INTO NEW ENGLAND. AT THE SURFACE...A WEAK COOL
FRONT HAS PUSHED INTO WESTERN AND NORTH CENTRAL NEBRASKA AND WAS
POSITIONED ROUGHLY ALONG INTERSTATE 80 FROM LINCOLN TO NORTH PLATTE.
THIS FRONTAL BOUNDARY HAS BEEN ENHANCED BY DECAYING CONVECTION AND
HAS ACTUALLY BEEN PUSHED FARTHER SOUTH THAN THE MODELS INDICATED
YESTERDAY. TEMPERATURES AS OF 3 PM CDT RANGED FROM THE UPPER 80S IN
THE NORTHEASTERN CWA...TO AROUND 100 IN THE SOUTHWEST.
&&
.UPDATE...
ISSUED AT 1005 PM CDT SAT SEP 7 2013
POPS HAVE BEEN REMOVED FOR THE OVERNIGHT FORECAST. THERE IS WAY
TOO MUCH DRY AIR IN THE MID LEVELS TO SUPPORT STORM DEVELOPMENT
AND EVEN THE HRRR HAS GONE SILENT DEVELOPING ANY CONVECTION. THE MCS ACROSS
SD PROBABLY WILL NOT AFFECT THE FCST AREA OVERNIGHT SO IT LOOKS
LIKE A DRY FORECAST OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 319 PM CDT SAT SEP 7 2013
MODELS INDICATE A WEAK DISTURBANCE TOPPING THE CENTRAL
PLAINS RIDGE LATER THIS EVENING ALLOWING FOR A ISOLATED MENTION OF
STORM DEVELOPMENT. THE MOST LIKELY SCENARIO INVOLVES STORMS FIRING
OFF THE HIGHER TERRAIN OF EASTERN WYOMING/WESTERN SOUTH DAKOTA LATE
THIS AFTERNOON...THEN DRIFTING SOUTHEAST OVERNIGHT ACROSS NORTH
CENTRAL NEBRASKA AND PORTIONS OF THE NORTHERN SANDHILLS. THUS WILL
MAINTAIN A SLIGHT CHANCE MENTION IN THIS AREA FOR NOW. ANOTHER
ABNORMALLY HOT DAY IS IN STORE FOR SUNDAY ACROSS MUCH OF WESTERN
NEBRASKA. HIGH TEMPERATURES WILL TOP IN THE MID 90S TO NEAR THE
CENTURY MARK FOR MOST LOCATIONS SAVE NORTH CENTRAL NEBRASKA WHERE A
GREATER SOUTHEASTERLY COMPONENT TO THE LOWER TROPOSPHERIC FLOW WILL
USHER IN SLIGHTLY COOLER TEMPERATURES. OTHERWISE PRECIPITATION
CHANCES WILL BE LIMITED TO FAR NORTHWESTERN PORTIONS OF THE CWA LATE
SUNDAY AS THE UPPER RIDGE AXIS SHIFTS SLIGHTLY TO THE EAST AND A
TROUGH DEEPENS OVER THE NORTHERN ROCKIES. A COLD FRONT WILL DROP
SOUTH THROUGH THE DAKOTAS AND APPROACH NW NEBRASKA BY LATE
AFTERNOON. THIS FRONT SHOULD PROVIDE A FOCUS FOR STORM DEVELOPMENT
WEST AND NORTH OF THE CWA BUT REMAIN REMOVED FROM THE FORECAST AREA.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 319 PM CDT SAT SEP 7 2013
SUNDAY NIGHT THROUGH TUESDAY...THE MAIN FORECASTING
CHALLENGE IS COLD FRONTAL TIMING MONDAY AFTERNOON/EVENING AND
ASSOCIATED PRECIPITATION CHANCES. ON SUNDAY NIGHT...A SEMISTATIONARY
FRONT WILL SLOWLY TRACK FROM THE WESTERN NEBRASKA PANHANDLE...INTO
THE EASTERN NEBRASKA PANHANDLE. TSRAS WILL CONTINUE INVOF OF THE
FRONT SUNDAY EVENING AND ARE NOT EXPECTED TO PERSIST INTO THE
OVERNIGHT HRS...AS THE BEST UPPER LEVEL SUPPORT CONTINUES OVER THE
WESTERN DAKOTAS AND NERN WYOMING. ON MONDAY...AN UPPER LEVEL TROUGH
OF LOW PRESSURE WILL MIGRATE ACROSS SRN SASKATCHEWAN...FORCING THE
COLD FRONT THROUGH THE FORECAST AREA BY LATE MONDAY AFTERNOON. THE
NAM AND GFS HAVE COME IN SLIGHTLY FASTER WITH THE FRONTAL TIMING TDY
COMPARED TO YESTERDAY...AND TRENDED MAX TEMPS DOWNWARD FROM THE
INHERITED FCST. LOW PRECIPITATION CHANCES WILL ACCOMPANY THE FRONTAL
PASSAGE...HOWEVER...HIGHER POPS ARE EXPECTED INTO MONDAY
EVENING...AS MID LEVEL FRONTOGENESIS INCREASES ACROSS THE SANDHILLS
INTO NORTHEASTERN PORTIONS OF THE FORECAST AREA. THIS MID LEVEL
FRONTOGENESIS WILL SHIFT SLOWLY SOUTH INTO SOUTHWESTERN NEBRASKA
OVERNIGHT INTO TUESDAY MORNING WITH THE CORRIDOR OF HIGHEST POPS
SHIFTING ACCORDINGLY.
TUESDAY NIGHT THROUGH SATURDAY...THE FRONTAL BOUNDARY WILL DROP
SOUTH INTO KANSAS STALLING ACROSS CENTRAL OR NORTHERN KANSAS TUESDAY
NIGHT INTO WEDNESDAY. AS WAS THE CASE YESTERDAY...LOCATION OF THE
FRONT...STILL IN SOME DOUBT WITH THE GFS FURTHER SOUTH WITH THIS
FEATURE COMPARED TO THE LATEST 12Z ECMWF. REGARDLESS OF MODEL
CHOICE...DECIDED TO CONFINE POPS TO THE SRN THIRD OF THE FORECAST
AREA WEDNESDAY AND WEDNESDAY NIGHT. BY THURSDAY...THE FRONT...WILL
SHIFT NORTH AS A WARM FRONT AS HIGH AMPLITUDE RIDGING BUILDS INTO
THE CENTRAL CONUS. PRECIPITATION CHANCES WILL SHIFT NORTH ALONG THE
FRONT THURSDAY INTO FRIDAY WITH DRY CONDS EXPECTED FRIDAY NIGHT INTO
SATURDAY. TEMPERATURES ON WEDNESDAY AND THURSDAY...WILL BE IN THE
UPPER 70S TO AROUND 80...WITH HIGHS REBOUNDING BACK INTO THE 80S FOR
FRIDAY AND SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1111 PM CDT SAT SEP 7 2013
VERY DRY AIR APPEARS TO BE IN PLACE ACROSS THE FCST AREA IN THE
MID LEVELS OF THE ATM. THUNDERSTORM ACTIVITY SHOULD REMAIN ACROSS
SD OVERNIGHT BUT THERE IS AN OUTSIDE CHANCE A STORM OR TWO COULD
BUILD INTO NRN NEB TONIGHT. OTHER ISOLATED STORMS COULD DEVELOP
AFTER 21Z SUNDAY ACROSS NWRN NEB. OTHERWISE VFR IS EXPECTED
THROUGHOUT THE FCST AREA.
&&
.FIRE WEATHER...
ISSUED AT 321 PM CDT SAT SEP 7 2013
MODEL GUIDANCE CONTINUE TO INDICATE MINIMUM RELATIVE HUMIDITY OF 20
PERCENT OR LESS SUNDAY AFTERNOON FOR FIRE ZONES
210...219...SOUTHERN/CENTRAL HALF OF ZONE 204...AND WESTERN PORTIONS
OF ZONE 206. TEMPERATURES THERE WILL RISE ONCE AGAIN TO NEAR 100
DEGREES WITH DEW POINTS FALLING INTO THE UPPER 40 TO LOW 50 DEGREE
RANGE. WINDS WILL BE STRONG AND FROM THE SOUTH WITH GUST POTENTIAL
OF 25 MPH OR GREATER ACROSS MUCH OF WESTERN NEBRASKA TOMORROW
AFTERNOON. FUELS MAY BE A LIMITING FACTOR HOWEVER AS THEY CONTINUE
TO CURE. SOME FIRE SPREAD IS POSSIBLE BUT WIDESPREAD LARGE/EXTREME
GROWTH IS NOT ANTICIPATED YET.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CDC
SYNOPSIS...CLB
SHORT TERM...JACOBS
LONG TERM...CLB
AVIATION...CDC
FIRE WEATHER...JACOBS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1046 PM EDT MON SEP 9 2013
.SYNOPSIS...
A WARM FRONT LIFTING ACROSS THE LOWER GREAT LAKES TONIGHT WILL BRING
A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS LATER TONIGHT THROUGH
EARLY TUESDAY ACROSS MUCH OF THE REGION. THIS WARM FRONT WILL
USHER IN UNSEASONABLY HOT AND MUGGY WEATHER TUESDAY AND
WEDNESDAY. EXPECT SHOWERS AND THUNDERSTORMS TO BREAK OUT WEDNESDAY
NIGHT AND THURSDAY AHEAD OF A COLD FRONT THAT WILL BRING A RETURN
TO MUCH COOLER WEATHER BY THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
RADAR IMAGERY SHOWING AN AREA OF SHOWERS SLOWLY INCREASING OVER
SOUTHERN ONTARIO. EXPECT THIS AREA OF SHOWERS TO CONTINUE TO SLOWLY
INCREASE IN COVERAGE AND INTENSITY OVER THE NEXT FEW HOURS AS WARM
ADVECTION INCREASES.
LATER TONIGHT OUR ATTENTION TURNS TO RAIN POTENTIAL ACROSS A BROADER
AREA. STRONG WARM ADVECTION WILL DEVELOP OVERNIGHT AS A WARM FRONTAL
ZONE OVER THE CENTRAL GREAT LAKES MOVES EAST. THE WARM ADVECTION AND
ISENTROPIC UPGLIDE WILL BE SUPPORTED BY A 35-40 KNOT LOW LEVEL
JET...WHICH WILL AID IN LIFT ACROSS THE WARM FRONTAL BOUNDARY AND
ALSO INCREASE MOISTURE CONVERGENCE OVERNIGHT. MESOSCALE MODEL
GUIDANCE IS TRENDING MORE AGGRESSIVE IN DEVELOPING SHOWERS AND A FEW
THUNDERSTORMS ALONG THE ADVANCING WARM FRONT OVERNIGHT. THE PAST FEW
RUNS OF THE HIGH RESOLUTION RAPID REFRESH /HRRR/ BRINGS AN ORGANIZED
AREA OF CONVECTION ACROSS LAKE ONTARIO AND INTO WESTERN AND CENTRAL
NY AROUND 10Z. THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY IS ALSO
WETTER AND FARTHER SOUTH THAN OPERATIONAL MODEL GUIDANCE...AND
BRINGS MEASURABLE RAIN INTO MUCH OF THE AREA IN THE 06Z-12Z TIME
FRAME.
THE HRRR GUIDANCE SEEMS TOO SLOW GIVEN UPSTREAM RADAR TRENDS...WITH
SHOWERS ALREADY SPREADING ACROSS THE THUMB OF MICHIGAN AT 2330Z.
TYPICALLY WITH AVERAGE STORM MOTION SHOWERS CAN MAKE IT FROM THE
THUMB TO WESTERN NY IN ABOUT 6 HOURS. ALSO OF NOTE...THE LAST FEW
VISIBLE SATELLITE SHOTS OF THE DAY SHOWED A NICE FIELD OF TEXTURED
CLOUDS ACROSS NORTHERN LOWER MICHIGAN...MARKING AN AREA OF MID LEVEL
ELEVATED INSTABILITY. GIVEN THE UPSTREAM RADAR AND SATELLITE
TRENDS...AM INCLINED TO BUY INTO THE MORE AGGRESSIVE MESOSCALE MODEL
SOLUTIONS FOR LATER TONIGHT.
THE MATURING MCS OVER EASTERN LAKE SUPERIOR WILL ALSO NEED TO BE
WATCHED FOR VERY LATE TONIGHT AND EARLY TUESDAY. IF THIS FEATURE
SURVIVES OVERNIGHT...IT SHOULD START TO TURN RIGHT SOME ALONG THE
INSTABILITY GRADIENT AND ALSO DUE TO THE INCREASING LOW LEVEL JET
AND ITS INFLUENCE ON CORFIDI VECTORS.
WITH THE ABOVE IN MIND...HAVE INCREASED POPS TO LIKELY AFTER
MIDNIGHT AND SPREAD POPS MUCH FARTHER TO THE SOUTH AND WEST...WITH
THE MOST LIKELY TRACK OF SHOWERS LATE TONIGHT FROM THE NIAGARA
FRONTIER INTO CENTRAL NY AND THE FINGER LAKES. EXPECT A FEW EMBEDDED
THUNDERSTORMS AS WELL WITH LOCALLY HEAVY DOWNPOURS IF THIS
MATERIALIZES.
ANY ONGOING SHOWERS AND THUNDERSTORMS SHOULD LIFT OFF TO OUR
NORTHEAST TUESDAY MORNING...LEAVING WESTERN AND NORTH-CENTRAL NEW
YORK HOT AND RAIN-FREE FOR THE REST OF THE DAY. RAIN-FREE..BUT NOT
DRY HOWEVER AS DEWPOINTS WELL SOAR INTO THE MID TO UPPER 60S. WITH
850MB TEMPS CLIMBING POTENTIALLY AS HIGH AS +22C AND SOUTHERLY
WINDS...LOOK FOR READINGS TO SOAR INTO THE 90S ACROSS MANY
AREAS...POSSIBLY EVEN FLIRTING WITH RECORD HIGHS AT ROCHESTER.
BUFFALO SHOULD BE SPARED THE HOTTEST TEMPERATURES THANKS TO BRISK
ONSHORE SOUTHWESTERLY FLOW...AS WILL THE NORTH COUNTRY...HOWEVER IT
WILL BE UNUSUALLY HOT ELSEWHERE.
REGARDING WINDS FOR TOMORROW...THE CLEARING SKIES AND SOARING
TEMPERATURES WILL ALLOW FOR PLENTY OF MIXING OF THE BOUNDARY
LAYER...AND THIS WILL LEAD TO GUSTY WINDS...PARTICULARLY ACROSS THE
NIAGARA FRONTIER AND ALONG LAKE ERIE WHERE THE STRONGEST WINDS ALOFT
WILL BE. NAM MODEL PROFILES INDICATE THAT GUSTS COULD APPROACH
ADVISORY LEVELS...HOWEVER THEY HAVE CONSTANTLY BEEN THE OUTLIERS ON
THE STRONG SIDE AND FOR NOW WILL SIDE WITH THE WEAKER GFS/ECMWF/GEM
AND MAINTAIN CONTINUITY WITH GUSTS TO AROUND 35 KNOTS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
IT WILL BE QUITE WARM TO START THIS PERIOD AS A LOW AMPLITUDE SPLIT
FLOW OVER THE LOWER 48 WILL INCLUDE AN ANOMALOUSLY WARM RIDGE THAT
WILL BE PARKED OVER THE SOUTHEASTERN STATES. THIS RIDGE WILL FEATURE
H925 TEMPS OF AT LEAST 20C (+3 STD) FOR THE SECOND DAY IN A ROW FOR
OUR FORECAST AREA...BUT A CHANGE TO MUCH COOLER WEATHER WILL BE ON
THE HORIZON. AS HEAD TOWARDS THE END OF THE WEEK...SIGNIFICANT
AMPLIFICATION WILL TAKE PLACE WITHIN A PHASED UPPER LEVEL FLOW. THIS
WILL PLACE A DEEP TROUGH OVER THE LOWER GREAT LKAES WHICH WILL
RESULT IN BELOW NORMAL TEMPS FOR THE END OF THE WEEK. MORE ON THIS
IN THE LONG TERM PORTION OF THIS DISCUSSION.
ALL OF WESTERN AND NORTH CENTRAL NEW YORK WILL BE POSITIONED DEEP
WITHIN A WARM SECTOR TUESDAY NIGHT...AS A STALLED WARM FRONTAL WILL
BE FOUND IN THE VCNTY OF THE OTTAWA VALLEY. WHILE THERE COULD BE A
SHOWER OR THUNDERSTORM OVER THE NORTH COUNTRY/THOUSAND ISLANDS
REGION EARLY THURSDAY NIGHT...DRY BUT SULTRY CONDITIONS WILL PREVAIL
OVER THE REGION. AFTER AN AFTERNOON OF NEAR RECORD HEAT...H85 TEMPS
OF +22C AND STRONG SOUTHERLY FLOW WILL EASILY HOLD OUR OVERNIGHT
TEMPS SOME 15 TO 20 DEG F ABV NORMAL VALUES WITH MINS NOT FAR 70.
THIS WILL BE FOLLOWED BY ANOTHER HOT AND HUMID DAY ON WEDNESDAY AS A
BROAD SOUTHWESTERLY FLOW WILL KEEP UNSEASONABLY WARM AIR IN PLACE.
H85 TEMPS NEAR 20C WILL ONCE AGAIN SUPPORT AFTERNOON TEMPS IN THE
UPPER 80S TO LOWER 90S IN THE VALLEYS AND LAKE PLAINS...SO WILL ADD
A FEW DEGREES TO CONTINUITY. THIS HEAT WILL COMBINE WITH DEW POINTS
IN THE UPPER 60S TO PROVIDE PLENTY OF FUEL FOR AFTERNOON CONVECTION.
SBCAPES ARE FORECAST TO REACH 1500-2000 J/KG AWAY FROM THE LAKES...
AND WHILE AIRMASSES LIKE THIS ARE TYPICALLY CAPPED...LAPSE RATES OF
8 TO >10 DEG C/KM ARE FORECAST UP THROUGH H6. THIS LARGE AMOUNT OF
INSTABILITY WILL NEED A TRIGGER TO BE REALIZED THOUGH...AND WITHOUT
ANY SYNOPTIC FORCING TO WORK WITH...THE `LIFTING` WILL HAVE TO COME
FROM LOCALIZED OROGRAPHICS OR LAKE BREEZE BOUNDARIES. THIS SHOULD
LIMIT CONVECTION TO AREAS WELL AWAY FROM THE LAKES...WITH THE LOWEST
POPS FOUND OVER THE IAG FRONTIER WHERE THE STABILIZING EFFECTS OF A
SOUTHWEST FLOW WILL BE IN PLACE. WILL THUS REMOVE MENTION OF STORMS
FOR THE IAG FRONTIER FROM CONTINUITY WHILE ADDING A LITTLE ENHANCED
WORDING FOR GUSTY WINDS TO THE STORMS OVER THE SRN TIER AND FINGER
LAKES.
A ROBUST SHORTWAVE OVER WESTERN ONTARIO WEDNESDAY EVENING WILL PUSH
A STRENGTHENING COLD FRONT ACROSS LOWER MICHIGAN AND SOUTHERN
ONTARIO DURING THE COURSE OF THE OVERNIGHT. WHILE THE FIRST OF
WEDNESDAY NIGHT SHOULD BE WARM AND RAIN FREE OVER MUCH OF OUR
REGION...SHOWERS AND THUNDERSTORMS WILL LIKELY DEVELOP OUT OF THE
FRONT BY DAYBREAK THURSDAY WHEN THE BOUNDARY IS FORECAST TO BE OVER
THE LOWER GREAT LAKES.
THE FRONT IS EXPECTED TO BE THROUGH OUR AREA BY EARLY THURSDAY
AFTERNOON WITH NOTABLY DRIER AND COOLER CANADIAN AIR CLEARING OUT
OUR SKIES FROM THE NORTHWEST. WILL TAPER OFF THE POPS ACCORDINGLY
WITH ONLY SLGT CHC POPS REMAINING EAST OF ROCHESTER BY EVENING. IN
TERMS OF TEMPERATURES...WE SHOULD MAX OUT IN THE MID 70S EARLY IN
THE DAY WITH STEADY OR SLOWLY FALLING MERCURY READINGS ANTICIPATED
FOR THE AFTERNOON WHEN DEW POINTS WILL DROP OFF THROUGH THE 50S.
OUR ATTENTION WILL TURN FROM SYNOPTIC TO MESOSCALE THURSDAY NIGHT AS
SEASONABLY CHILLY AIR WILL POUR ACROSS THE LOWER LAKES IN ADVANCE OF
AN EXPANSIVE AREA OF HIGH PRESSURE OVER WESTERN ONTARIO. H85 TEMPS
ARE PROJECTED TO DROP TO ARND 4C BY DAYBREAK FRIDAY...AND WITH A
DEEP CYCLONIC NORTHWEST FLOW IN PLACE...THERE WILL CERTAINLY BE
ENOUGH LAKE INSTABILITY TO SUPPORT SOME LAKE CLOUDINESS...AND
POSSIBLY NUISANCE SHOWERS EAST/SOUTHEAST OF LK ONTARIO. LOW
TEMPERATURES WILL RANGE FROM THE LOWER 50S ACROSS THE LAKE PLAINS TO
THE MID 40S IN THE SRN TIER VALLEYS/EAST OF THE BLACK RIVER VALLEY.
THESE READINGS WILL BE AT LEAST 15 DEG F LOWER THEN PREVIOUS NIGHTS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
TEMPERATURES WILL AVERAGE NEAR TO BELOW NORMAL DURING THIS PERIOD AS
AN AMPLIFIED LONGWAVE PATTERN OVER THE LOWER 48 WILL BREAK DOWN...
LEAVING MORE OF A ZONAL FLOW ACROSS OUR REGION.
A VIGOROUS SHORTWAVE WILL DROP INTO THE BASE OF A LONGWAVE TROUGH
CENTERED OVER THE LOWER GREAT LAKES ON FRIDAY. THIS FEATURE WILL
COUPLE WITH STRONG COLD ADVECTION TO PRODUCE SOME SHOWERS SOUTH OF
LAKE ONTARIO DURING THE MIDDAY AND AFTERNOON...WHILE TEMPERATURES
WILL STRUGGLE TO REACH 60. THE STRONG MID LEVEL FEATURE WILL SWING
OFF ACROSS NEW ENGLAND FRIDAY NIGHT...WHILE STRONG RIDGING WILL
BUILD IN FROM THE UPPER GREAT LAKES. THIS WILL QUICKLY CLEAR OUT ANY
LEFTOVER SHOWER ACTIVITY...ALTHOUGH SOME NUISANCE LAKE DRIVEN
SHOWERS CANNOT BE RULED OUT WITHIN WEAK CYCLONIC FLOW BETWEEN ROC
AND SYR.
BOTH DAYS OF THE WEEKEND WILL THEN BE DOMINATED BY AN EXPANSIVE AREA
OF HIGH PRESSURE THAT WILL BE PARKED OVER THE GREAT LAKES REGION.
WHILE IT WILL BE SEASONABLY COOL ON SATURDAY WITH HIGHS CLOSE TO
60...WEAK WARM ADVECTION DURING THE SECOND HALF OF THE WEEKEND WILL
BOOST DAYTIME TEMPS BY SOME 10 DEGREES FOR SUNDAY. THIS WILL
TRASNLATE INTO READINGS THAT WILL BE RIGHT ON TARGET FOR NORMALS IN
MID SEPTEMBER...WHICH ARE WITHIN A FEW DEGREES OF 70.
CONFIDENCE IN THE FORECAST WILL DROP OFF SIGNIFICANTLY ON MONDAY...
AS THE DETERMINISTIC PACKAGES ARE AT ODDS OVER THE PASSAGE OF THE
NEXT FRONTAL SYSTEM. WILL CARRY SLGT CHC POPS FOR NOW WHILE LEAVING
TEMPS CLOSE TO THOSE FROM SUNDAY.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH ABOUT 08Z WITH VARYING AMOUNTS
OF MID LEVEL CLOUD CROSSING THE REGION.
LATER TONIGHT A STRONG WARM FRONT WILL CROSS THE REGION WITH
INCREASING COVERAGE OF SHOWERS ACROSS MUCH OF THE AREA...ALONG WITH
A FEW EMBEDDED THUNDERSTORMS. THIS WILL BRING BRIEF PERIODS OF
MVFR/IFR CONDITIONS IN ANY OF THE HEAVIER SHOWERS. THE SHOWERS AND
ANY THUNDER WILL END FROM SOUTHWEST TO NORTHEAST TUESDAY MORNING AS
THE WARM FRONT LIFTS NORTHEAST ACROSS THE AREA. ANY LINGERING
MVFR/IFR CONDITIONS ASSOCIATED WITH THE SHOWERS WILL ALSO END.
FOLLOWING THE WARM FRONT...SKIES WILL CLEAR AND WINDS WILL BECOME
RATHER STRONG WITH GUSTS OF AROUND 30 KNOTS LIKELY ACROSS WESTERN NY
FROM KBUF-KIAG-KROC...WITH 20-25 KNOTS ELSEWHERE.
ALSO OF NOTE...SOME LOW LEVEL WIND SHEAR IS LIKELY LATER TONIGHT AND
EARLY TUESDAY MORNING AS A 35-40 KNOT LOW LEVEL JET CROSSES THE
AREA. WINDS WILL STILL BE STRONG JUST OFF THE DECK ON TUESDAY...BUT
AS SURFACE WINDS INCREASE THIS WILL ALLEVIATE ANY SHEAR.
OUTLOOK...
TUESDAY NIGHT AND WEDNESDAY...VFR.
WEDNESDAY NIGHT AND THURSDAY...MAINLY VFR WITH SHOWERS LIKELY AND A
CHANCE OF THUNDERSTORMS ALONG WITH ASSOCIATED BRIEF MVFR/IFR.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
SATURDAY...VFR.
&&
.MARINE...
RELATIVELY LIGHT WINDS ON THE LAKES THIS EVENING WILL GRADUALLY
STRENGTHEN OVERNIGHT AS A WARM FRONT LIFTS NORTH ACROSS THE REGION.
THIS FRONT WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS...MAINLY
TO THE WATERS OF LAKE ONTARIO...LATER TONIGHT AND INTO TUESDAY
MORNING. EXPECT SOUTHWESTERLY FLOW TO FRESHEN ON TUESDAY AS AN AREA
OF LOW PRESSURE SKIRTS BY TO THE NORTH OF THE LAKES WITH WINDS
STRENGTHENING ENOUGH TO WARRANT SMALL CRAFT ADVISORIES FOR THE
NEARSHORE WATERS OF EASTERN LAKE ERIE/WESTERN LAKE ONTARIO ON
TUESDAY. WINDS WILL ALSO INCREASE TO SMALL CRAFT ADVISORY LEVELS AT
THE NORTHEAST END OF LAKE ONTARIO. THESE WINDS SHOULD RELAX TUESDAY
NIGHT AS THE LOW WEAKENS.
SHOWERS AND THUNDERSTORMS WILL BE A THREAT ONCE AGAIN WEDNESDAY
NIGHT INTO THURSDAY AHEAD OF A COLD FRONT THAT IS EXPECTED TO CROSS
THE LAKES LATER ON THURSDAY...BRINGING ANOTHER CHANCE OF SMALL CRAFT
ADVISORY LEVEL NORTHWESTERLY WINDS.
&&
.CLIMATE...
NEXT TUESDAY AND WEDNESDAY A LATE SUMMER AIRMASS WILL SETTLE ACROSS
THE REGION WITH MANY AREAS WELL INTO THE 80S. BELOW ARE THE RECORD
HIGHS...AND RECORD WARM LOWS FOR OUR THREE CLIMATE SITES:
BUFFALO..
TUESDAY HIGH: 90 (1955) LOW: 75 (1983)
WEDNESDAY HIGH: 87 (1952) LOW: 72 (1931)
ROCHESTER..
TUESDAY HIGH: 94 (1897) LOW: 73 (1925)
WEDNESDAY HIGH: 94 (1931) LOW: 71 (1931)
WATERTOWN..
TUESDAY HIGH: 90 (1959) LOW: 70 (1962)
WEDNESDAY HIGH: 89 (1961) LOW: 70 (1961)
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM EDT TUESDAY FOR LEZ020-
040-041.
SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM EDT TUESDAY
FOR LOZ030.
SMALL CRAFT ADVISORY FROM 10 AM TO 8 PM EDT TUESDAY FOR
LOZ042-043.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT TUESDAY FOR
LOZ045.
&&
$$
SYNOPSIS...HITCHCOCK/WOOD
NEAR TERM...HITCHCOCK/WOOD
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...HITCHCOCK
MARINE...WOOD
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1038 PM EDT MON SEP 9 2013
.SYNOPSIS...
THE NEXT COUPLE OF DAYS WILL FEATURE A BRIEF RETURN TO SUMMER
WEATHER BEFORE TEMPERATURES COOL BACK OFF TO MORE FALL-LIKE
LEVELS BY THE END OF THE WEEK AND INTO THE WEEKEND. THERE WILL
ALSO BE SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS FROM LATE
TONIGHT THROUGH THURSDAY...SOME POTENTIALLY STRONG TO
SEVERE...ESPECIALLY LATE WEDNESDAY.
&&
.NEAR TERM /UNTIL 8 AM TUESDAY MORNING/...
AS OF 1038 PM EDT MONDAY...MOSTLY MINOR TWEAKS MADE TO
TEMPERATURES AND DEWPOINTS TO ACCOUNT FOR LATEST SFC OBSERVATIONS.
HOWEVER...AN ELEVATED MCS THAT IS NOW EXITING LAKE SUPERIOR HAS
RESULTED IN SOME MORE SIGNIFICANT CHANGES TO POPS TOWARDS THE
MORNING. THIS MCS HAS FORMED ON NORTHERN EDGE OF INSTABILITY
GRADIENT WHICH EXTENDS FROM THE NORTHERN GREAT LAKES INTO SOUTHERN
NY/PA. BASED ON CORFIDI VECTORS BEING NORTHWEST AROUND 25-30 KTS
EXPECT THIS MCS TO MOVE SOUTHEASTWARD. LATEST HRRR AND RAP
SIMULATED REFLECTIVITY PROGS TAKE THE COMPLEX SOUTHEASTWARD
ACROSS CENTRAL NEW YORK AROUND SUNRISE. ITS EVOLUTION & TRACK WILL
BE MONITORED THIS EVENING FOR ANY SHIFT NORTHWARD. THOUGH THE
ENTIRE NORTH COUNTRY WILL STAND TO SEE SHOWERS/THUNDERSTORMS
TOWARDS MORNING DUE TO THE STRONG WARM ADVECTION & ISENTROPIC LIFT
THAT WILL BE TAKING PLACE...I SUSPECT THE BEST CHANCE AT
THUNDERSTORMS WOULD BE FOR OUR SOUTHWESTERN CWA AREAS /FROM AN
OGDENSBURG- SARANAC LAKE- NEWCOMB LINE/. I HAVE RAISED POPS
ACCORDINGLY IN THE ADIRONDACKS AND SOUTHERN SAINT LAWRENCE COUNTY
TO BETTER REFLECT ABOVE REASONING. UNTIL THEN...EXPECT SKIES TO
CONTINUE TO FILL IN WITH TEMPERATURES LEVELING OFF BEFORE RISING
TOWARDS MORNING.
&&
.SHORT TERM /8 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 325 PM EDT MONDAY...ACTIVE PERIOD OF WEATHER CONTINUES ON
TUESDAY...WITH THE POTENTIAL FOR A FEW STRONG-SEVERE
THUNDERSTORMS. MORNING SHOWERS/TSTORMS ASSOCIATED WITH STRONG WAA
AND CONVECTIVE COMPLEX SHOULD PUSH EAST OF THE REGION BY AROUND
15Z. AT THE SAME TIME THE SURFACE WARM FRONT WILL LIFT
NORTHEASTWARD AND BE DRAPED ACROSS THE AREA...LIKELY BISECTING
THE REGION. THE POSITION OF THIS WARM FRONT IS QUITE CRITICAL FOR
ANY SEVERE CONVECTIVE THREAT. ON SOUTH SIDE OF FRONT...EXPECTING
AT LEAST PARTIAL CLEARING LEADING TO DEVELOPMENT OF 1000-2000
J/KG OF MLCAPE BY LATE WEDNESDAY. THIS COMBINED WITH NEAR 50
KNOTS OF 0-6KM SHEAR AND 20-30 KNOTS OF 0-1KM SHEAR WILL LEAD TO
A CONDITIONAL THREAT OF SEVERE WEATHER. FORECAST SOUNDINGS FOR
TUESDAY AFTERNOON AT BTV/SLK/OGS SHOW CAPPING INVERSION LIMITING
OVERALL CONVECTIVE INITIATION. THUS WILL BE RELYING ON RELATIVELY
WEAK FORCING WITH POSSIBLE LEFTOVER BOUNDARIES FROM EARLY MORNING
CONVECTION OR THE WARM FRONT ITSELF. ON THE COOLER NORTH SIDE OF
BOUNDARY...ANY CONVECTIVE ACTIVITY IS LIKELY TO BE MORE ELEVATED
IN NATURE. THAT ALL BEING SAID...CURRENT THINKING IS THAT WARM
FRONT WILL BE SITUATED FROM THE SAINT LAWRENCE VALLEY ACROSS THE
ADIRONDACKS AND INTO THE CHAMPLAIN VALLEY...WITH THE BEST THREAT
OF ISOLATED SEVERE WEATHER FROM THE CHAMPLAIN VALLEY WESTWARD
ACROSS THE ADIRONDACKS AND INTO THE SAINT LAWRENCE VALLEY WHERE
CONVERGENCE MAY BE ENHANCED BY NORTHEAST FLOW DOWN THE NORTHERN
SAINT LAWRENCE VALLEY. WHILE COVERAGE IS EXPECTED TO BE
LIMITED...ANY THUNDERSTORM THAT MAY DEVELOP ALONG THE WARM FRONT
HAS THE POTENTIAL TO BECOME SEVERE WITH LARGE HAIL...DAMAGING
WINDS...HEAVY RAIN...AND A VERY LOW CHANCE OF A TORNADO.
OTHERWISE...HIGHS WILL ALSO BE VERY DEPENDENT ON POSITION OF WARM
FRONT WITH LOW 80S ON THE WARM SIDE AND LOW 70S ON THE COOL SIDE.
SYNOPTIC WIND GUSTS OUTSIDE OF THUNDERSTORM ACTIVITY WILL LIKELY
REACH 20-30 MPH ON WARM SIDE OF FRONT IN PRONOUNCED SOUTHWEST
FLOW.
THE FRONTAL BOUNDARY WILL REMAIN NEAR THE REGION INTO TUESDAY
NIGHT...WITH INSTABILITY REMAINING...ESPECIALLY ALOFT WITH
PRESENCE OF AN ELEVATED MIXED LAYER. THIS COMBINED WITH ABUNDANT
MOISTURE...AS NOTED BY 1.5-2" PRECIPITABLE WATER VALUES...WILL
KEEP THE CHANCE OF SHOWERS/THUNDERSTORMS AROUND THROUGH THE
NIGHT. TEMPERATURES WILL HAVE TROUBLE FALLING...SO LOOKING AT A
LOT OF UPPER 60S AND LOWER 70S.
POTENTIALLY MORE WIDESPREAD STRONG-SEVERE THUNDERSTORMS ARE
POSSIBLE LATER WEDNESDAY. THE WEAK BOUNDARY WILL REMAIN NEAR THE
REGION...AND FORCING WILL BE ENHANCED BY THE APPROACH OF AN UPPER
TROUGH FROM THE WEST...ESPECIALLY LATER WEDNESDAY AND INTO
WEDNESDAY NIGHT. THE AREA IS EXPECTED TO BE LARGELY INTO THE WARM
SECTOR WITH WIDESPREAD 80S FOR HIGHS...POSSIBLY EVEN A SPOT 90F
IN THE CHAMPLAIN VALLEY. THIS COUPLED WITH DEW POINTS IN THE
UPPER 60S TO NEAR 70 WILL PRODUCE A VERY UNSTABLE AIRMASS WITH
UPWARDS OF 2000 J/KG OF MLCAPE. SHEAR PROFILES STILL LOOK VERY
FAVORABLE FOR STRONG-SEVERE THUNDERSTORM DEVELOPMENT WITH 40-50
KNOTS OF 0-6KM SHEAR ANTICIPATED. 0-1KM SHEAR VALUES ARE
SIGNIFICANTLY LOWER THAN TUESDAY...WITH MAIN POTENTIAL IMPACTS
BEING LARGE HAIL AND DAMAGING WINDS. GREATEST THREAT OF SEVERE
THUNDERSTORMS SHOULD BE 21Z-03Z. GIVEN HIGH MOISTURE
CONTENT...HEAVY RAIN AND MINOR FLOODING WILL BE POSSIBLE IN ANY
THUNDERSTORMS.
COLD FRONT NEARS THE REGION LATER WEDNESDAY NIGHT WITH POTENTIAL
FOR ELEVATED CONVECTIVE ACTIVITY CONTINUING. STRONG SOUTHWEST FLOW
IS ALSO MAINTAINED SO LOWS IN THE UPPER 60S/LOWER 70S LOOK GOOD
AGAIN.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 345 PM EDT MONDAY...COLD FRONT WILL MOVE THROUGH THE NORTH
COUNTRY FROM WEST TO EAST THURSDAY INTO THURSDAY NIGHT...
PRODUCING SHOWERS AND THUNDERSTORMS ACROSS THE AREA. THIS FRONT
WILL EXIT SERN VT EARLY FRIDAY MORNING WITH LINGERING SHOWERS
PSBL AS THE ASSOCIATED UPPER LEVEL TROUGH BRINGS A POTENT
SHORTWAVE THRU THE REGION ON FRIDAY...KEEPING SKIES MOSTLY
CLOUDY. NW-N WINDS WILL INCREASE AT THE SFC WITH TIGHT PRESSURE
GRADIENT IN PLACE AS A RIDGE OF HIGH PRESSURE BUILD OVER THE
GREAT LAKES REGION. COLDER AIR WILL USHER IN ON THE NORTHERLY
FLOW BEHIND THE AFOREMENTIONED COLD FRONT WITH 850MB TEMPS
DROPPING TO 0C-2C BY LATE FRIDAY. THIS WILL BRING THE SLIGHTLY
WARMER THAN NORMAL TEMPS OF M-U70S ON THURSDAY COOLING TO THE
M50S-L60S ON FRIDAY...WITH MIN TEMPS IN THE 30S-L40S.
THE UPPER LEVEL TROUGH WILL EXIT TO THE EAST SOMETIME LATE
SATURDAY INTO EARLY SUNDAY...WITH CLOUDS DECREASING OVER THE AREA
AND RIDGE OF HIGH PRESSURE AT THE SFC SLIDING EAST...CENTERED
OVER SRN NY/NRN PA AREA. THIS WILL BRING SRLY FLOW AND MODERATING
TEMPERATURES TO THE NORTH COUNTRY SUNDAY AND MONDAY. MAX TEMPS
WILL BE IN THE M-U60S AND MIN TEMPS IN THE U30S-U40S.
MODEL GUIDANCE DIVERGES ON SOLNS TOWARD THE END OF THE PERIOD.
HIGH PRESSURE LOOKS TO KEEP THINGS DRY THROUGH AT LEAST SUNDAY
NT/EARLY MONDAY. GFS BRINGS ANOTHER LOW PRESSURE SYSTEM ACROSS
THE ERN GREAT LAKES BY MONDAY AFTN...WITH ANOTHER COLD FRONT
DRAPED TO THE SW BRINGING SHOWERS AND PSBL TSTMS TO END THE
PERIOD. THE 12Z ECMWF KEEPS THE HIGH PRESSURE OVER THE AREA
THROUGH LATE TUESDAY.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
THROUGH 00Z WEDNESDAY...VFR CONDS EXPECTED THROUGH 08-10Z WITH
SCT/BKN HIGH CLOUDS AND LIGHT SOUTHERLY FLOW FROM 3-8 KTS.
EXCEPTION AT KRUT WHERE SOUTHEASTERLY DRAINAGE FLOWS AROUND 10KTS
EXPECTED OVERNIGHT. APPROACH OF STRONG WARM FRONT TOWARD TUESDAY
MORNING WILL BRING A PERIOD OF SCT SHOWERS/ISOLD THUNDER TO MOST
TERMINALS IN THE 08-14Z TIME FRAME. DRY CONDS MAY PREVAIL AT KRUT.
MAINLY VFR AS ACTIVITY PASSES THOUGH SOME BKN/OVC MVFR CIGS
POSSIBLE AT KMSS/KSLK/KMPV THROUGH THE MORNING HOURS ON TUESDAY.
AFTER 16-18Z WARM FRONT SLOWLY LIFTS TO THE INTL BORDER WITH
INCREASINGLY GUSTY SOUTH/SOUTHWESTERLY FLOW. SOME GUSTS TO 25 KTS
POSSIBLE AT KBTV/KPBG. WHILE THREAT CONDITIONAL...NATL STORM
PREDICTION CENTER CONTINUES TO HIGHLIGHT AREA IN SLIGHT RISK OF
SVR WX LATER TOMORROW/TOMORROW EVENING ON THE SOUTHERN SIDE OF THE
FRONT. HAVE KEPT MOST TERMINALS DRY DUE TO UNCERTAINTY OF
CONVECTIVE DEVELOPMENT. PLEASE NOTE HOWEVER THAT IF ANY STORMS CAN
FORM...THREAT OF ISOLD STRONG/SVR WX IS POSSIBLE.
OUTLOOK 00Z WEDNESDAY THROUGH SATURDAY...
PRIMARILY VFR...THOUGH PERIODS OF IFR/MVFR VSBYS WITH SCATTERED
SHOWERS AND THUNDERSTORMS AS WARM FRONT MOVES THROUGH REGION
TUESDAY FOLLOWED BY COLD FRONTAL PASSAGE THURSDAY. A FEW OF THE
STORMS MAY BE STRONG TO LOCALLY SEVERE TUESDAY EVENING ALONG THE
INTL BORDER...AND ACROSS THE ENTIRE FCST AREA WEDNESDAY AFTERNOON
AND EVENING. ANY STORMS THAT DO BECOME SEVERE MAY CONTAIN STRONG
TURBULENCE...LARGE HAIL AND STRONG SFC WINDS. THE UPPER LEVEL
TROUGH ASSOCIATED WITH THESE FRONTS WILL MOVE THROUGH
FRIDAY...KEEPING A THREAT OF SHOWERS OVER THE NORTH COUNTRY
THROUGH LATE FRIDAY. SATURDAY HIGH PRESSURE WILL BUILD IN AT THE
SFC.
&&
.EQUIPMENT...
AS OF 719 PM EDT SATURDAY...NOAA WEATHER RADIO STATION WXM 44,
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR DUE TO A DAMAGED ANTENNA. REPLACEMENT PARTS HAVE BEEN
ORDERED AND THE REPAIR WORK HAS NOW BEEN SCHEDULED FOR SEPTEMBER
17-20.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MUCCILLI
NEAR TERM...LOCONTO/MUCCILLI
SHORT TERM...MUCCILLI
LONG TERM...KGM
AVIATION...JMG/KGM
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BUFFALO NY
816 PM EDT MON SEP 9 2013
.SYNOPSIS...
A WARM FRONT LIFTING ACROSS THE LOWER GREAT LAKES TONIGHT WILL BRING
A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS LATER TONIGHT THROUGH
EARLY TUESDAY ACROSS MUCH OF THE REGION. THIS WARM FRONT WILL
USHER IN UNSEASONABLY HOT AND MUGGY WEATHER TUESDAY AND
WEDNESDAY. EXPECT SHOWERS AND THUNDERSTORMS TO BREAK OUT WEDNESDAY
NIGHT AND THURSDAY AHEAD OF A COLD FRONT THAT WILL BRING A RETURN
TO MUCH COOLER WEATHER BY THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
A FEW SHOWERS NEAR THE PA STATE LINE WILL CONTINUE TO DRIFT EAST
ACROSS PORTIONS OF THE SOUTHERN TIER AND WEAKEN THROUGH THE EVENING
HOURS. THESE APPEAR TO BE IN ASSOCIATION WITH A WEAK MID LEVEL
SHORTWAVE AND AREA OF CONVERGENCE MOVING THROUGH WESTERN PA.
LATER TONIGHT OUR ATTENTION TURNS TO RAIN POTENTIAL ACROSS A BROADER
AREA. STRONG WARM ADVECTION WILL DEVELOP OVERNIGHT AS A WARM FRONTAL
ZONE OVER THE CENTRAL GREAT LAKES MOVES EAST. THE WARM ADVECTION AND
ISENTROPIC UPGLIDE WILL BE SUPPORTED BY A 35-40 KNOT LOW LEVEL
JET...WHICH WILL AID IN LIFT ACROSS THE WARM FRONTAL BOUNDARY AND
ALSO INCREASE MOISTURE CONVERGENCE OVERNIGHT. MESOSCALE MODEL
GUIDANCE IS TRENDING MORE AGGRESSIVE IN DEVELOPING SHOWERS AND A FEW
THUNDERSTORMS ALONG THE ADVANCING WARM FRONT OVERNIGHT. THE PAST FEW
RUNS OF THE HIGH RESOLUTION RAPID REFRESH /HRRR/ BRINGS AN ORGANIZED
AREA OF CONVECTION ACROSS LAKE ONTARIO AND INTO WESTERN AND CENTRAL
NY AROUND 10Z. THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY IS ALSO
WETTER AND FARTHER SOUTH THAN OPERATIONAL MODEL GUIDANCE...AND
BRINGS MEASURABLE RAIN INTO MUCH OF THE AREA IN THE 06Z-12Z TIME
FRAME.
THE HRRR GUIDANCE SEEMS TOO SLOW GIVEN UPSTREAM RADAR TRENDS...WITH
SHOWERS ALREADY SPREADING ACROSS THE THUMB OF MICHIGAN AT 2330Z.
TYPICALLY WITH AVERAGE STORM MOTION SHOWERS CAN MAKE IT FROM THE
THUMB TO WESTERN NY IN ABOUT 6 HOURS. ALSO OF NOTE...THE LAST FEW
VISIBLE SATELLITE SHOTS OF THE DAY SHOWED A NICE FIELD OF TEXTURED
CLOUDS ACROSS NORTHERN LOWER MICHIGAN...MARKING AN AREA OF MID LEVEL
ELEVATED INSTABILITY. GIVEN THE UPSTREAM RADAR AND SATELLITE
TRENDS...AM INCLINED TO BUY INTO THE MORE AGGRESSIVE MESOSCALE MODEL
SOLUTIONS FOR LATER TONIGHT.
WITH THE ABOVE IN MIND...HAVE INCREASED POPS TO LIKELY AFTER
MIDNIGHT AND SPREAD POPS MUCH FARTHER TO THE SOUTH AND WEST...WITH
THE MOST LIKELY TRACK OF SHOWERS LATE TONIGHT FROM THE NIAGARA
FRONTIER INTO CENTRAL NY AND THE FINGER LAKES. EXPECT A FEW EMBEDDED
THUNDERSTORMS AS WELL WITH LOCALLY HEAVY DOWNPOURS IF THIS
MATERIALIZES.
ANY ONGOING SHOWERS AND THUNDERSTORMS SHOULD LIFT OFF TO OUR
NORTHEAST TUESDAY MORNING...LEAVING WESTERN AND NORTH-CENTRAL NEW
YORK HOT AND RAIN-FREE FOR THE REST OF THE DAY. RAIN-FREE..BUT NOT
DRY HOWEVER AS DEWPOINTS WELL SOAR INTO THE MID TO UPPER 60S. WITH
850MB TEMPS CLIMBING POTENTIALLY AS HIGH AS +22C AND SOUTHERLY
WINDS...LOOK FOR READINGS TO SOAR INTO THE 90S ACROSS MANY
AREAS...POSSIBLY EVEN FLIRTING WITH RECORD HIGHS AT ROCHESTER.
BUFFALO SHOULD BE SPARED THE HOTTEST TEMPERATURES THANKS TO BRISK
ONSHORE SOUTHWESTERLY FLOW...AS WILL THE NORTH COUNTRY...HOWEVER IT
WILL BE UNUSUALLY HOT ELSEWHERE.
REGARDING WINDS FOR TOMORROW...THE CLEARING SKIES AND SOARING
TEMPERATURES WILL ALLOW FOR PLENTY OF MIXING OF THE BOUNDARY
LAYER...AND THIS WILL LEAD TO GUSTY WINDS...PARTICULARLY ACROSS THE
NIAGARA FRONTIER AND ALONG LAKE ERIE WHERE THE STRONGEST WINDS ALOFT
WILL BE. NAM MODEL PROFILES INDICATE THAT GUSTS COULD APPROACH
ADVISORY LEVELS...HOWEVER THEY HAVE CONSTANTLY BEEN THE OUTLIERS ON
THE STRONG SIDE AND FOR NOW WILL SIDE WITH THE WEAKER GFS/ECMWF/GEM
AND MAINTAIN CONTINUITY WITH GUSTS TO AROUND 35 KNOTS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
IT WILL BE QUITE WARM TO START THIS PERIOD AS A LOW AMPLITUDE SPLIT
FLOW OVER THE LOWER 48 WILL INCLUDE AN ANOMALOUSLY WARM RIDGE THAT
WILL BE PARKED OVER THE SOUTHEASTERN STATES. THIS RIDGE WILL FEATURE
H925 TEMPS OF AT LEAST 20C (+3 STD) FOR THE SECOND DAY IN A ROW FOR
OUR FORECAST AREA...BUT A CHANGE TO MUCH COOLER WEATHER WILL BE ON
THE HORIZON. AS HEAD TOWARDS THE END OF THE WEEK...SIGNIFICANT
AMPLIFICATION WILL TAKE PLACE WITHIN A PHASED UPPER LEVEL FLOW. THIS
WILL PLACE A DEEP TROUGH OVER THE LOWER GREAT LKAES WHICH WILL
RESULT IN BELOW NORMAL TEMPS FOR THE END OF THE WEEK. MORE ON THIS
IN THE LONG TERM PORTION OF THIS DISCUSSION.
ALL OF WESTERN AND NORTH CENTRAL NEW YORK WILL BE POSITIONED DEEP
WITHIN A WARM SECTOR TUESDAY NIGHT...AS A STALLED WARM FRONTAL WILL
BE FOUND IN THE VCNTY OF THE OTTAWA VALLEY. WHILE THERE COULD BE A
SHOWER OR THUNDERSTORM OVER THE NORTH COUNTRY/THOUSAND ISLANDS
REGION EARLY THURSDAY NIGHT...DRY BUT SULTRY CONDITIONS WILL PREVAIL
OVER THE REGION. AFTER AN AFTERNOON OF NEAR RECORD HEAT...H85 TEMPS
OF +22C AND STRONG SOUTHERLY FLOW WILL EASILY HOLD OUR OVERNIGHT
TEMPS SOME 15 TO 20 DEG F ABV NORMAL VALUES WITH MINS NOT FAR 70.
THIS WILL BE FOLLOWED BY ANOTHER HOT AND HUMID DAY ON WEDNESDAY AS A
BROAD SOUTHWESTERLY FLOW WILL KEEP UNSEASONABLY WARM AIR IN PLACE.
H85 TEMPS NEAR 20C WILL ONCE AGAIN SUPPORT AFTERNOON TEMPS IN THE
UPPER 80S TO LOWER 90S IN THE VALLEYS AND LAKE PLAINS...SO WILL ADD
A FEW DEGREES TO CONTINUITY. THIS HEAT WILL COMBINE WITH DEW POINTS
IN THE UPPER 60S TO PROVIDE PLENTY OF FUEL FOR AFTERNOON CONVECTION.
SBCAPES ARE FORECAST TO REACH 1500-2000 J/KG AWAY FROM THE LAKES...
AND WHILE AIRMASSES LIKE THIS ARE TYPICALLY CAPPED...LAPSE RATES OF
8 TO >10 DEG C/KM ARE FORECAST UP THROUGH H6. THIS LARGE AMOUNT OF
INSTABILITY WILL NEED A TRIGGER TO BE REALIZED THOUGH...AND WITHOUT
ANY SYNOPTIC FORCING TO WORK WITH...THE `LIFTING` WILL HAVE TO COME
FROM LOCALIZED OROGRAPHICS OR LAKE BREEZE BOUNDARIES. THIS SHOULD
LIMIT CONVECTION TO AREAS WELL AWAY FROM THE LAKES...WITH THE LOWEST
POPS FOUND OVER THE IAG FRONTIER WHERE THE STABILIZING EFFECTS OF A
SOUTHWEST FLOW WILL BE IN PLACE. WILL THUS REMOVE MENTION OF STORMS
FOR THE IAG FRONTIER FROM CONTINUITY WHILE ADDING A LITTLE ENHANCED
WORDING FOR GUSTY WINDS TO THE STORMS OVER THE SRN TIER AND FINGER
LAKES.
A ROBUST SHORTWAVE OVER WESTERN ONTARIO WEDNESDAY EVENING WILL PUSH
A STRENGTHENING COLD FRONT ACROSS LOWER MICHIGAN AND SOUTHERN
ONTARIO DURING THE COURSE OF THE OVERNIGHT. WHILE THE FIRST OF
WEDNESDAY NIGHT SHOULD BE WARM AND RAIN FREE OVER MUCH OF OUR
REGION...SHOWERS AND THUNDERSTORMS WILL LIKELY DEVELOP OUT OF THE
FRONT BY DAYBREAK THURSDAY WHEN THE BOUNDARY IS FORECAST TO BE OVER
THE LOWER GREAT LAKES.
THE FRONT IS EXPECTED TO BE THROUGH OUR AREA BY EARLY THURSDAY
AFTERNOON WITH NOTABLY DRIER AND COOLER CANADIAN AIR CLEARING OUT
OUR SKIES FROM THE NORTHWEST. WILL TAPER OFF THE POPS ACCORDINGLY
WITH ONLY SLGT CHC POPS REMAINING EAST OF ROCHESTER BY EVENING. IN
TERMS OF TEMPERATURES...WE SHOULD MAX OUT IN THE MID 70S EARLY IN
THE DAY WITH STEADY OR SLOWLY FALLING MERCURY READINGS ANTICIPATED
FOR THE AFTERNOON WHEN DEW POINTS WILL DROP OFF THROUGH THE 50S.
OUR ATTENTION WILL TURN FROM SYNOPTIC TO MESOSCALE THURSDAY NIGHT AS
SEASONABLY CHILLY AIR WILL POUR ACROSS THE LOWER LAKES IN ADVANCE OF
AN EXPANSIVE AREA OF HIGH PRESSURE OVER WESTERN ONTARIO. H85 TEMPS
ARE PROJECTED TO DROP TO ARND 4C BY DAYBREAK FRIDAY...AND WITH A
DEEP CYCLONIC NORTHWEST FLOW IN PLACE...THERE WILL CERTAINLY BE
ENOUGH LAKE INSTABILITY TO SUPPORT SOME LAKE CLOUDINESS...AND
POSSIBLY NUISANCE SHOWERS EAST/SOUTHEAST OF LK ONTARIO. LOW
TEMPERATURES WILL RANGE FROM THE LOWER 50S ACROSS THE LAKE PLAINS TO
THE MID 40S IN THE SRN TIER VALLEYS/EAST OF THE BLACK RIVER VALLEY.
THESE READINGS WILL BE AT LEAST 15 DEG F LOWER THEN PREVIOUS NIGHTS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
TEMPERATURES WILL AVERAGE NEAR TO BELOW NORMAL DURING THIS PERIOD AS
AN AMPLIFIED LONGWAVE PATTERN OVER THE LOWER 48 WILL BREAK DOWN...
LEAVING MORE OF A ZONAL FLOW ACROSS OUR REGION.
A VIGOROUS SHORTWAVE WILL DROP INTO THE BASE OF A LONGWAVE TROUGH
CENTERED OVER THE LOWER GREAT LAKES ON FRIDAY. THIS FEATURE WILL
COUPLE WITH STRONG COLD ADVECTION TO PRODUCE SOME SHOWERS SOUTH OF
LAKE ONTARIO DURING THE MIDDAY AND AFTERNOON...WHILE TEMPERATURES
WILL STRUGGLE TO REACH 60. THE STRONG MID LEVEL FEATURE WILL SWING
OFF ACROSS NEW ENGLAND FRIDAY NIGHT...WHILE STRONG RIDGING WILL
BUILD IN FROM THE UPPER GREAT LAKES. THIS WILL QUICKLY CLEAR OUT ANY
LEFTOVER SHOWER ACTIVITY...ALTHOUGH SOME NUISANCE LAKE DRIVEN
SHOWERS CANNOT BE RULED OUT WITHIN WEAK CYCLONIC FLOW BETWEEN ROC
AND SYR.
BOTH DAYS OF THE WEEKEND WILL THEN BE DOMINATED BY AN EXPANSIVE AREA
OF HIGH PRESSURE THAT WILL BE PARKED OVER THE GREAT LAKES REGION.
WHILE IT WILL BE SEASONABLY COOL ON SATURDAY WITH HIGHS CLOSE TO
60...WEAK WARM ADVECTION DURING THE SECOND HALF OF THE WEEKEND WILL
BOOST DAYTIME TEMPS BY SOME 10 DEGREES FOR SUNDAY. THIS WILL
TRASNLATE INTO READINGS THAT WILL BE RIGHT ON TARGET FOR NORMALS IN
MID SEPTEMBER...WHICH ARE WITHIN A FEW DEGREES OF 70.
CONFIDENCE IN THE FORECAST WILL DROP OFF SIGNIFICANTLY ON MONDAY...
AS THE DETERMINISTIC PACKAGES ARE AT ODDS OVER THE PASSAGE OF THE
NEXT FRONTAL SYSTEM. WILL CARRY SLGT CHC POPS FOR NOW WHILE LEAVING
TEMPS CLOSE TO THOSE FROM SUNDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
A FEW SCATTERED SHOWERS WILL MOVE EAST ALONG THE NY/PA BORDER
THROUGH MID EVENING WITH LOCAL MVFR/IFR WITHIN THE SHOWERS AND JUST
BEHIND THEM. OTHERWISE VFR WILL PREVAIL THROUGH THE FIRST HALF OF
THE NIGHT WITH A MIX OF MID LEVEL CLOUDS CROSSING THE AREA. LATER
TONIGHT A STRONG WARM FRONT WILL CROSS THE REGION WITH INCREASING
COVERAGE OF SHOWERS ACROSS MUCH OF THE AREA...ALONG WITH A FEW
EMBEDDED THUNDERSTORMS. THIS WILL BRING BRIEF PERIODS OF MVFR/IFR
CONDITIONS IN ANY OF THE HEAVIER SHOWERS. THE SHOWERS AND ANY
THUNDER WILL END FROM SOUTHWEST TO NORTHEAST TUESDAY MORNING AS THE
WARM FRONT LIFTS NORTHEAST ACROSS THE AREA. ANY LINGERING MVFR/IFR
CONDITIONS ASSOCIATED WITH THE SHOWERS WILL ALSO END.
FOLLOWING THE WARM FRONT...SKIES WILL CLEAR AND WINDS WILL BECOME
RATHER STRONG WITH GUSTS OF AROUND 30 KNOTS LIKELY ACROSS WESTERN NY
FROM KBUF-KIAG-KROC...WITH 20-25 KNOTS ELSEWHERE.
ALSO OF NOTE...SOME LOW LEVEL WIND SHEAR IS LIKELY LATER TONIGHT AND
EARLY TUESDAY MORNING AS A 35-40 KNOT LOW LEVEL JET CROSSES THE
AREA. WINDS WILL STILL BE STRONG JUST OFF THE DECK ON TUESDAY...BUT
AS SURFACE WINDS INCREASE THIS WILL ALLEVIATE ANY SHEAR.
OUTLOOK...
TUESDAY NIGHT AND WEDNESDAY...VFR.
WEDNESDAY NIGHT AND THURSDAY...MAINLY VFR WITH SHOWERS LIKELY AND A
CHANCE OF THUNDERSTORMS ALONG WITH ASSOCIATED BRIEF MVFR/IFR.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
SATURDAY...VFR.
&&
.MARINE...
RELATIVELY LIGHT WINDS ON THE LAKES THIS EVENING WILL GRADUALLY
STRENGTHEN OVERNIGHT AS A WARM FRONT LIFTS NORTH ACROSS THE REGION.
THIS FRONT WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS...MAINLY
TO THE WATERS OF LAKE ONTARIO...LATER TONIGHT AND INTO TUESDAY
MORNING. EXPECT SOUTHWESTERLY FLOW TO FRESHEN ON TUESDAY AS AN AREA
OF LOW PRESSURE SKIRTS BY TO THE NORTH OF THE LAKES WITH WINDS
STRENGTHENING ENOUGH TO WARRANT SMALL CRAFT ADVISORIES FOR THE
NEARSHORE WATERS OF EASTERN LAKE ERIE/WESTERN LAKE ONTARIO ON
TUESDAY. WINDS WILL ALSO INCREASE TO SMALL CRAFT ADVISORY LEVELS AT
THE NORTHEAST END OF LAKE ONTARIO. THESE WINDS SHOULD RELAX TUESDAY
NIGHT AS THE LOW WEAKENS.
SHOWERS AND THUNDERSTORMS WILL BE A THREAT ONCE AGAIN WEDNESDAY
NIGHT INTO THURSDAY AHEAD OF A COLD FRONT THAT IS EXPECTED TO CROSS
THE LAKES LATER ON THURSDAY...BRINGING ANOTHER CHANCE OF SMALL CRAFT
ADVISORY LEVEL NORTHWESTERLY WINDS.
&&
.CLIMATE...
NEXT TUESDAY AND WEDNESDAY A LATE SUMMER AIRMASS WILL SETTLE ACROSS
THE REGION WITH MANY AREAS WELL INTO THE 80S. BELOW ARE THE RECORD
HIGHS...AND RECORD WARM LOWS FOR OUR THREE CLIMATE SITES:
BUFFALO..
TUESDAY HIGH: 90 (1955) LOW: 75 (1983)
WEDNESDAY HIGH: 87 (1952) LOW: 72 (1931)
ROCHESTER..
TUESDAY HIGH: 94 (1897) LOW: 73 (1925)
WEDNESDAY HIGH: 94 (1931) LOW: 71 (1931)
WATERTOWN..
TUESDAY HIGH: 90 (1959) LOW: 70 (1962)
WEDNESDAY HIGH: 89 (1961) LOW: 70 (1961)
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM EDT TUESDAY FOR LEZ020-
040-041.
SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM EDT TUESDAY
FOR LOZ030.
SMALL CRAFT ADVISORY FROM 10 AM TO 8 PM EDT TUESDAY FOR
LOZ042-043.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT TUESDAY FOR
LOZ045.
&&
$$
SYNOPSIS...HITCHCOCK/WOOD
NEAR TERM...HITCHCOCK/WOOD
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...HITCHCOCK
MARINE...WOOD
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
756 PM EDT MON SEP 9 2013
.SYNOPSIS...
A WARM FRONT LIFTING ACROSS THE LOWER GREAT LAKES TONIGHT WILL BRING
A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS LATER TONIGHT THROUGH
EARLY TUESDAY ACROSS MUCH OF THE REGION. THIS WARM FRONT WILL
USHER IN UNSEASONABLY HOT AND MUGGY WEATHER TUESDAY AND
WEDNESDAY. EXPECT SHOWERS AND THUNDERSTORMS TO BREAK OUT WEDNESDAY
NIGHT AND THURSDAY AHEAD OF A COLD FRONT THAT WILL BRING A RETURN
TO MUCH COOLER WEATHER BY THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
A FEW SHOWERS NEAR THE PA STATE LINE WILL CONTINUE TO DRIFT EAST
ACROSS PORTIONS OF THE SOUTHERN TIER AND WEAKEN THROUGH THE EVENING
HOURS. THESE APPEAR TO BE IN ASSOCIATION WITH A WEAK MID LEVEL
SHORTWAVE AND AREA OF CONVERGENCE MOVING THROUGH WESTERN PA.
LATER TONIGHT OUR ATTENTION TURNS TO RAIN POTENTIAL ACROSS A BROADER
AREA. STRONG WARM ADVECTION WILL DEVELOP OVERNIGHT AS A WARM FRONTAL
ZONE OVER THE CENTRAL GREAT LAKES MOVES EAST. THE WARM ADVECTION AND
ISENTROPIC UPGLIDE WILL BE SUPPORTED BY A 35-40 KNOT LOW LEVEL
JET...WHICH WILL AID IN LIFT ACROSS THE WARM FRONTAL BOUNDARY AND
ALSO INCREASE MOISTURE CONVERGENCE OVERNIGHT. MESOSCALE MODEL
GUIDANCE IS TRENDING MORE AGGRESSIVE IN DEVELOPING SHOWERS AND A FEW
THUNDERSTORMS ALONG THE ADVANCING WARM FRONT OVERNIGHT. THE PAST FEW
RUNS OF THE HIGH RESOLUTION RAPID REFRESH /HRRR/ BRINGS AN ORGANIZED
AREA OF CONVECTION ACROSS LAKE ONTARIO AND INTO WESTERN AND CENTRAL
NY AROUND 10Z. THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY IS ALSO
WETTER AND FARTHER SOUTH THAN OPERATIONAL MODEL GUIDANCE...AND
BRINGS MEASURABLE RAIN INTO MUCH OF THE AREA IN THE 06Z-12Z TIME
FRAME.
THE HRRR GUIDANCE SEEMS TOO SLOW GIVEN UPSTREAM RADAR TRENDS...WITH
SHOWERS ALREADY SPREADING ACROSS THE THUMB OF MICHIGAN AT 2330Z.
TYPICALLY WITH AVERAGE STORM MOTION SHOWERS CAN MAKE IT FROM THE
THUMB TO WESTERN NY IN ABOUT 6 HOURS. ALSO OF NOTE...THE LAST FEW
VISIBLE SATELLITE SHOTS OF THE DAY SHOWED A NICE FIELD OF TEXTURED
CLOUDS ACROSS NORTHERN LOWER MICHIGAN...MARKING AN AREA OF MID LEVEL
ELEVATED INSTABILITY. GIVEN THE UPSTREAM RADAR AND SATELLITE
TRENDS...AM INCLINED TO BUY INTO THE MORE AGGRESSIVE MESOSCALE MODEL
SOLUTIONS FOR LATER TONIGHT.
WITH THE ABOVE IN MIND...HAVE INCREASED POPS TO LIKELY AFTER
MIDNIGHT AND SPREAD POPS MUCH FARTHER TO THE SOUTH AND WEST...WITH
THE MOST LIKELY TRACK OF SHOWERS LATE TONIGHT FROM THE NIAGARA
FRONTIER INTO CENTRAL NY AND THE FINGER LAKES. EXPECT A FEW EMBEDDED
THUNDERSTORMS AS WELL WITH LOCALLY HEAVY DOWNPOURS IF THIS
MATERIALIZES.
ANY ONGOING SHOWERS AND THUNDERSTORMS SHOULD LIFT OFF TO OUR
NORTHEAST TUESDAY MORNING...LEAVING WESTERN AND NORTH-CENTRAL NEW
YORK HOT AND RAIN-FREE FOR THE REST OF THE DAY. RAIN-FREE..BUT NOT
DRY HOWEVER AS DEWPOINTS WELL SOAR INTO THE MID TO UPPER 60S. WITH
850MB TEMPS CLIMBING POTENTIALLY AS HIGH AS +22C AND SOUTHERLY
WINDS...LOOK FOR READINGS TO SOAR INTO THE 90S ACROSS MANY
AREAS...POSSIBLY EVEN FLIRTING WITH RECORD HIGHS AT ROCHESTER.
BUFFALO SHOULD BE SPARED THE HOTTEST TEMPERATURES THANKS TO BRISK
ONSHORE SOUTHWESTERLY FLOW...AS WILL THE NORTH COUNTRY...HOWEVER IT
WILL BE UNUSUALLY HOT ELSEWHERE.
REGARDING WINDS FOR TOMORROW...THE CLEARING SKIES AND SOARING
TEMPERATURES WILL ALLOW FOR PLENTY OF MIXING OF THE BOUNDARY
LAYER...AND THIS WILL LEAD TO GUSTY WINDS...PARTICULARLY ACROSS THE
NIAGARA FRONTIER AND ALONG LAKE ERIE WHERE THE STRONGEST WINDS ALOFT
WILL BE. NAM MODEL PROFILES INDICATE THAT GUSTS COULD APPROACH
ADVISORY LEVELS...HOWEVER THEY HAVE CONSTANTLY BEEN THE OUTLIERS ON
THE STRONG SIDE AND FOR NOW WILL SIDE WITH THE WEAKER GFS/ECMWF/GEM
AND MAINTAIN CONTINUITY WITH GUSTS TO AROUND 35 KNOTS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
A RETURN TO MID SUMMER WARMTH...AND ONE OF THE WARMEST DAYS THIS
YEAR...WILL START THIS PERIOD. SHOWERS AND THUNDERSTORMS...OF WHICH
SOME OF THESE STORMS COULD BECOME STRONG TO SEVERE AHEAD OF A COLD FRONT
WILL END THIS PERIOD WITH TEMPERATURES DROPPING TO BELOW NORMAL.
ALOFT ON TUESDAY A BROAD RIDGE OF HIGH PRESSURE WILL HAVE SHIFTED FROM THE
CENTRAL PLAINS EASTWARD TOWARDS THE TENNESSEE VALLEY AND SOUTHEAST.
A SHORTWAVE TROUGH ALOFT WILL BE CRESTING THIS RIDGE...LOCATED
TUESDAY MORNING NEAR THE UPPER PLAIN STATES.
AT THE SURFACE A WARM FRONT WILL CONTINUE TO LIFT NORTHWARD THROUGH
THE CWA CARRYING RAIN SHOWERS AND ISOLATED THUNDERSTORMS INTO THE
NORTH COUNTRY. THERE WILL BE THREE SENSIBLE WEATHER HIGHLIGHTS
TUESDAY...HEAT...WINDS AND THUNDERSTORMS.
HEAT...BEHIND THIS WARM FRONT UNSEASONABLY WARM TEMPERATURES WILL BE
FOUND AS THE RECENT HEAT ACROSS THE PLAINS SLIDES NORTHEASTWARD. THE
CENTER OF A 592 DM 500 HPA RIDGE WILL REMAIN WELL TO OUR SOUTH OVER
THE SOUTHEASTERN STATES...BUT ITS AXIS WILL CROSS THE EASTERN GREAT
LAKES REGION TUESDAY. AT 850 HPA TEMPERATURES WILL RISE TO 20 TO AS
MUCH AS 22C WHICH WOULD FACTOR AT 2 SD ABOVE NORMAL. THESE
TEMPERATURES ALOFT WILL TRANSLATE TO AFTERNOON HIGHS WELL IN TO THE
80S...WITH THE VALLEYS WARMER INCLUDING THE GENESEE VALLEY WHERE LOW
90S ARE LIKELY. A SOUTHWEST WIND OFF A LOW 70S LAKE WILL KEEP AREAS
AROUND BUFFALO AND JUST NORTH OF WATERTOWN A FEW DEGREES COOLER. FOR
MORE DETAILS ON RECORD TEMPERATURES TUESDAY AND WEDNESDAY PLEASE
REFERENCE THE CLIMATE SECTION BELOW. WITH THE WARMEST DAYS THIS YEAR
IN THE LOW TO MID 90S ACROSS THE REGION...THIS TUESDAY WILL BE ONE OF
THE WARMEST DAYS THIS YEAR...AND POSSIBLY A FEW LOCATIONS IN THE
GENESEE VALLEY COULD HAVE A SHOT OF TUESDAY BEING THE WARMEST DAY OF
THE YEAR. WHEN FACTORING IN THE HUMIDITY TUESDAY`S AFTERNOON APPARENT
TEMPERATURES WILL SOAR WELL INTO THE 90S ACROSS THE LOWER ELEVATIONS
OF WESTERN NEW YORK...AND POSSIBLY UPPER 90S WITHIN THE GENESEE
VALLEY AND NORTHERN FINGER LAKES REGION.
WINDS...TUESDAY WILL ALSO BE QUITE BREEZY AS THE PRESSURE GRADIENT
INCREASES BETWEEN HIGH PRESSURE ARCHED ALONG THE EAST COAST AND THE
NEARING COLD FRONT BOUNDARY AND ASSOCIATED STORM SYSTEM OVER THE
CENTRAL AND WESTERN GREAT LAKES. SOUTHWEST WINDS WILL AID IN WARMING
THE VALLEYS OF THE CWA...WHILE ALSO GUSTING DOWNWIND OF LAKE ERIE
INTO THE 35 TO 40 MPH RANGE. THE 00Z NAM IS QUITE A BIT STRONGER
WITH THE LLJ (45-50 KNOTS) THAN THE 00Z GFS AND ECMWF (35-40 KNOTS)
AND WILL FAVOR THE LATTER TWO MODELS...GIVEN THAT THE LOW PASSING TO
OUR NORTH IS ALSO WEAKENING.
THESE SOUTHWEST WINDS BEHIND A WARM FRONT THAT WILL STALL NEAR THE
US AND CANADIAN BORDER WILL ALSO BRING INCREASING MOISTURE AND
HUMIDITY INTO THE REGION. DEWPOINTS WILL RISE INTO THE MID AND UPPER
60S...WHICH COMBINED WITH THE VERY WARM TEMPERATURES WILL BRING
IMPRESSIVE SBCAPE VALUES TO OUR REGION. SBCAPES RANGING FROM 2000 TO
JUST OVER 2500 J/KG ARE POSSIBLE BEHIND THIS WARM FRONT...HOWEVER
WITH NO TRIGGER TO INITIATE CONVECTION (UPPER LEVEL SHORTWAVE RIDING
TO OUR NORTH ALONG THE CANADIAN BORDER) AS WELL AS WARMING IN THE
MID LEVELS...WILL LEAVE AREAS SOUTH OF THE WARM FRONT DRY ON
TUESDAY. ALSO AREAS SOUTH OF LAKE ONTARIO TEND TO HAVE A HARD TIME
FORMING THUNDERSTORMS WITH GUSTY SOUTHWEST WINDS...AND THESE FACTORS
WILL ALL SUPPORT A DRY DAY TUESDAY BEHIND THE WARM FRONT.
THUNDERSTORMS...THERE WILL ALSO BE A CHANCE FOR A FEW THUNDERSTORMS
ALONG THE WARM FRONTAL BOUNDARY THAT WILL STALL NEAR US AND CANADIAN
BORDER ON TUESDAY. AREAS POSSIBLE FOR STORMS WILL BE THE NORTH
COUNTRY...AS WELL AS PORTIONS OF EASTERN LAKE ONTARIO AND POSSIBLY
OSWEGO COUNTY. IN ADDITION TO THE SBCAPES OF 1000 TO 1500 J/KG
THROUGH THIS REGION...THERE WILL BE A SLIGHTLY STRONGER LLJ THROUGH
THE REGION IN ADDITION TO THE FRONTAL BOUNDARY AND PASSAGE OF A WEAK
UPPER LEVEL SHORTWAVE THAT COULD INITIATE CONVECTION. THERE WILL ALSO
BE UPPER LEVEL SUPPORT WITH A 110 KNOT 250 HPA JET PASSING ACROSS
CENTRAL QUEBEC CANADA. THE RIGHT ENTRANCE REGION WILL PASS ACROSS
THE CANADIAN AND US BORDER...AIDING IN LARGE SCALE LIFT.
THE WATERTOWN BUFKIT HODOGRAPH DEPICTS STRONG LOW LEVEL WIND SHEAR
WITHIN THE 0-3 KM LAYER...AND HELICITY VALUES OF 200 TO 400 M2/S2.
EXPECT THE LOW LEVEL WIND SHEAR TO TAKE ON MORE OF THE CLASSIC
HOCKEY STICK SIGNATURE...WITH STRONGER WIND SHEAR WITHIN THE 0-1 KM
LAYER CLOSER TO THE WARM FRONT WHICH WILL BE NEAR THE SAINT LAWRENCE
VALLEY AND JUST THE OTHER SIDE OF THE US BORDER. WITH THESE
PARAMETERS IN MIND...WILL CONTINUE THE MENTION OF POSSIBLE SEVERE
THUNDERSTORMS IN THE HWO FOR THE EASTERN LAKE ONTARIO REGION...WITH
THE GREATEST THREAT FOR A SEVERE THUNDERSTORM TO BE ACROSS THE FAR
NORTHERN PORTIONS OF THE NORTH COUNTRY. ANY TORNADO THREAT ON
TUESDAY MAY BE JUST ACROSS THE CWA BORDER WHERE THE STRONGER 0-1 KM
WIND SHEAR WILL BE FOUND. EXACT LOCATION OF POSSIBLY SEVERE STORMS
WILL OF COURSE DEPEND UPON WHERE THE WARM FRONT STALLS.
TUESDAY NIGHT WILL CONTINUE TO BE MUGGY AND LARGELY BE QUIET SOUTH
OF LAKE ONTARIO...WHILE THE STALLING WARM FRONT WILL CONTINUE THE
POTENTIAL FOR SHOWERS AND THUNDERSTORMS OVERNIGHT ACROSS THE NORTH
COUNTRY. CENTERED WITHIN THE WARM SECTOR OF THIS STORM SYSTEM THIS
NIGHT WILL BE UNSEASONABLY WARM WITH TEMPERATURES LIKELY TO NOT DROP
OUT OF THE LOW 70S ACROSS MUCH OF THE CWA. INLAND AND ACROSS THE
HILL TOPS WILL BE SLIGHTLY COOLER AND THESE AREAS WILL BE THE
LOCATIONS THAT WILL DROP INTO THE UPPER 60S.
WEDNESDAY WILL CONTINUE THE UNSEASONABLY WARM CONDITIONS ACROSS THE
REGION...THOUGH LIKELY A DEGREE OR TWO LESS THAN TUESDAY. THE LOW
PRESSURE THAT WILL DRAG A WEAKENING COLD FRONT INTO THE CWA
WEDNESDAY WILL NOT BE AS DEEP AS WHAT IT WAS ON TUESDAY
MORNING...SUCH THAT THE PRESSURE GRADIENT BETWEEN THE SOUTHEAST AREA
OF HIGH PRESSURE AND LOW PRESSURE WILL NOT BE AS GREAT. THE LIGHTER
WIND FLOW...COMBINED WITH ADDITIONAL CLOUD COVER WILL STILL BRING A
VERY WARM DAY...THOUGH TEMPERATURES WILL LIKELY BE A DEGREE OR SO
LESS THAN TUESDAY.
WITH THE INCREASING MOISTURE/CLOUDS WEDNESDAY COUPLED WITH THE WEAK
COLD FRONT CROSSING INTO THE AREA THERE WILL BE INCREASING CHANCES
FOR SHOWERS AND THUNDERSTORMS. THIS COLD FRONT WILL WEAKEN SOME AS
IT ADVANCES AHEAD OF THE MAIN UPPER LEVEL TROUGH WHICH WILL REMAIN
ACROSS THE CENTRAL GREAT LAKES WEDNESDAY. STILL LIFT FROM THIS
FEATURE...COMBINED WITH DAYTIME INSTABILITY AND PWATS CLIMBING
TOWARDS 1.50 TO 2.00 INCHES SHOULD ALLOW FOR SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH THE DAY. A SOUTHWEST WIND OFF LAKE ERIE MAY
LIMIT THE DAYTIME INSTABILITY SUCH THAT AREAS THROUGH THE NORTHERN
NIAGARA FRONTIER MAY REMAIN DRY THROUGH THE DAYTIME HOURS. WILL
CONTINUE WITH JUST A LOW CHANCE POP FOR THESE AREAS ON WEDNESDAY.
STORMS ON WEDNESDAY COULD BECOME STRONG ACROSS THE EASTERN
GREAT LAKES REGION THROUGH THE AFTERNOON HOURS WITH SBCAPES AGAIN
RISING TO 1000 TO 2000 J/KG WITH A HUMID BOUNDARY LAYER. THERE WILL
ALSO BE A POTENTIAL FOR HEAVIER BURSTS OF RAIN WITH THE ABOVE NORMAL
PWATS. THE 0-6 KM BULK SHEAR VALUES OF 30 KNOTS SHOULD KEEP STORMS
MOVING...BUT COULD ALSO PRODUCE SOME GUSTY WINDS FROM THESE PULSING
THUNDERSTORMS.
WEDNESDAY NIGHT AND INTO THURSDAY IS WHEN WE EXPECT THE MOST
EXPANSIVE COVERAGE OF SHOWERS AND THUNDERSTORMS. THIS IS WHEN
HEIGHTS ALOFT WILL BEGIN TO FALL AHEAD OF A SHORTWAVE TROUGH THAT
WILL BE DIVING DOWN INTO THE CENTRAL GREAT LAKES REGION. WITH THE
STILL WARM BOUNDARY LAYER AND INSTABILITY OF 250 TO 500 J/KG THAT
WILL REMAIN THROUGH THE NIGHT AND WITH UPPER LEVEL TROUGH AND ITS
ASSOCIATED COLD FRONT NEARING WESTERN NEW YORK EXPECT EXPANDING
AREAS OF SHOWERS AND THUNDERSTORMS WEDNESDAY NIGHT ACROSS WESTERN
NEW YORK...AND ALSO NEAR THE NORTH COUNTRY NEAR THE LINGERING OLD
FRONTAL BOUNDARY. THIS ACTIVITY WILL THEN CONTINUE THROUGH
THURSDAY...WITH THUNDERSTORMS AGAIN BECOME MORE EXPANSIVE ACROSS THE
GENESEE VALLEY AND POINTS EAST IN THE DAYTIME HEATING. TEMPERATURES
THURSDAY WILL BE WARMEST TO THE EAST AHEAD OF THE COLD FRONT WHERE
MID TO UPPER 70S WILL BE FOUND. BEHIND THE COLD FRONT TEMPERATURES
ACROSS WESTERN NEW YORK MAY BEGIN TO FALL THROUGH THE DAYTIME.
MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THIS COLD FRONT CARRYING
JUST TO OUR EAST THURSDAY NIGHT. SHOWERS AND THUNDERSTORMS MAY
LINGER IN THE EVENING HOURS THURSDAY TO THE FAR EASTERN ZONES OF THE
CWA...OTHERWISE A DRYING AND COOLING TREND IS EXPECTED THROUGH THE
OVERNIGHT HOURS. TEMPERATURES AT 850 HPA WILL FALL INTO THE LOW
SINGLE DIGITS BEHIND THE FRONT...COLD ENOUGH THAT LAKE EFFECT
CLOUDINESS AND POSSIBLY A SHOWER WILL LINGER SOUTH AND EAST OF LAKE
ONTARIO...AND POSSIBLY EAST OF LAKE ERIE. LOWS THURSDAY NIGHT WILL
FALL BACK INTO THE 50S...WITH UPPER 40S ACROSS THE HIGHER INTERIOR
SECTIONS. THESE READINGS WILL BE A DEGREE OR SO BELOW NORMAL.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
A SHARP TRANSITION TO NOTICEABLY COOLER CONDITIONS WILL TAKE PLACE
FRIDAY AS THE DEEP UPPER LEVEL TROUGH AND COOL POOL SETTLES OVER NEW
YORK STATE AND NEW ENGLAND. LINGERING MOISTURE AND SOMEWHAT UNSTABLE
AIR IN THE VICINITY OF THE TROUGH MAY GENERATE A FEW MORE SHOWERS
FRIDAY. ALSO CONTRIBUTING TO THE SHOWERS ON FRIDAY WILL BE A COOL
FLOW OVER THE WARM LAKE WATERS...WITH PERHAPS A FEW SHOWERS
SOUTHEAST OF THE LAKES FRIDAY MORNING. HIGHS ON FRIDAY WILL BE SOME
8 TO 10 DEGREES BELOW NORMAL...WITH AFTERNOON READINGS IN THE UPPER
50S AND LOWER 60S. THIS WILL ALSO BE ABOUT 25 TO 30 DEGREES COOLER
THAN TUESDAY AND WEDNESDAY HIGH TEMPERATURES.
SATURDAY AND SUNDAY BROAD AREA OF HIGH PRESSURE WILL PUSH INTO THE
NORTHEAST BEHIND THE COLD FRONT...AND OUTSIDE OF RIVER VALLEY FOG
ACROSS THE INLAND AREAS SATURDAY AND SUNDAY SHOULD BE FINE WITH
PLENTY OF SUNSHINE AND LOWER HUMIDITY. SATURDAY WILL BE THE COOLEST
OF THE TWO WEEKEND DAYS...AS WINDS SUNDAY SHIFT TO MORE OF A
SOUTHERLY FLOW WITH THE HIGH PRESSURE PUSHING EASTWARD. LOOK FOR
HIGHS SATURDAY IN THE UPPER 50S TO LOWER 60S...WITH SUNDAY ABOUT 5
TO 10 DEGREES WARMER.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
A FEW SCATTERED SHOWERS WILL MOVE EAST ALONG THE NY/PA BORDER
THROUGH MID EVENING WITH LOCAL MVFR/IFR WITHIN THE SHOWERS AND JUST
BEHIND THEM. OTHERWISE VFR WILL PREVAIL THROUGH THE FIRST HALF OF
THE NIGHT WITH A MIX OF MID LEVEL CLOUDS CROSSING THE AREA. LATER
TONIGHT A STRONG WARM FRONT WILL CROSS THE REGION WITH INCREASING
COVERAGE OF SHOWERS ACROSS MUCH OF THE AREA...ALONG WITH A FEW
EMBEDDED THUNDERSTORMS. THIS WILL BRING BRIEF PERIODS OF MVFR/IFR
CONDITIONS IN ANY OF THE HEAVIER SHOWERS. THE SHOWERS AND ANY
THUNDER WILL END FROM SOUTHWEST TO NORTHEAST TUESDAY MORNING AS THE
WARM FRONT LIFTS NORTHEAST ACROSS THE AREA. ANY LINGERING MVFR/IFR
CONDITIONS ASSOCIATED WITH THE SHOWERS WILL ALSO END.
FOLLOWING THE WARM FRONT...SKIES WILL CLEAR AND WINDS WILL BECOME
RATHER STRONG WITH GUSTS OF AROUND 30 KNOTS LIKELY ACROSS WESTERN NY
FROM KBUF-KIAG-KROC...WITH 20-25 KNOTS ELSEWHERE.
ALSO OF NOTE...SOME LOW LEVEL WIND SHEAR IS LIKELY LATER TONIGHT AND
EARLY TUESDAY MORNING AS A 35-40 KNOT LOW LEVEL JET CROSSES THE
AREA. WINDS WILL STILL BE STRONG JUST OFF THE DECK ON TUESDAY...BUT
AS SURFACE WINDS INCREASE THIS WILL ALLEVIATE ANY SHEAR.
OUTLOOK...
TUESDAY NIGHT AND WEDNESDAY...VFR.
WEDNESDAY NIGHT AND THURSDAY...MAINLY VFR WITH SHOWERS LIKELY AND A
CHANCE OF THUNDERSTORMS ALONG WITH ASSOCIATED BRIEF MVFR/IFR.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
SATURDAY...VFR.
&&
.MARINE...
RELATIVELY LIGHT WINDS ON THE LAKES THIS EVENING WILL GRADUALLY
STRENGTHEN OVERNIGHT AS A WARM FRONT LIFTS NORTH ACROSS THE REGION.
THIS FRONT WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS...MAINLY
TO THE WATERS OF LAKE ONTARIO...LATER TONIGHT AND INTO TUESDAY
MORNING. EXPECT SOUTHWESTERLY FLOW TO FRESHEN ON TUESDAY AS AN AREA
OF LOW PRESSURE SKIRTS BY TO THE NORTH OF THE LAKES WITH WINDS
STRENGTHENING ENOUGH TO WARRANT SMALL CRAFT ADVISORIES FOR THE
NEARSHORE WATERS OF EASTERN LAKE ERIE/WESTERN LAKE ONTARIO ON
TUESDAY. WINDS WILL ALSO INCREASE TO SMALL CRAFT ADVISORY LEVELS AT
THE NORTHEAST END OF LAKE ONTARIO. THESE WINDS SHOULD RELAX TUESDAY
NIGHT AS THE LOW WEAKENS.
SHOWERS AND THUNDERSTORMS WILL BE A THREAT ONCE AGAIN WEDNESDAY
NIGHT INTO THURSDAY AHEAD OF A COLD FRONT THAT IS EXPECTED TO CROSS
THE LAKES LATER ON THURSDAY...BRINGING ANOTHER CHANCE OF SMALL CRAFT
ADVISORY LEVEL NORTHWESTERLY WINDS.
&&
.CLIMATE...
NEXT TUESDAY AND WEDNESDAY A LATE SUMMER AIRMASS WILL SETTLE ACROSS
THE REGION WITH MANY AREAS WELL INTO THE 80S. BELOW ARE THE RECORD
HIGHS...AND RECORD WARM LOWS FOR OUR THREE CLIMATE SITES:
BUFFALO..
TUESDAY HIGH: 90 (1955) LOW: 75 (1983)
WEDNESDAY HIGH: 87 (1952) LOW: 72 (1931)
ROCHESTER..
TUESDAY HIGH: 94 (1897) LOW: 73 (1925)
WEDNESDAY HIGH: 94 (1931) LOW: 71 (1931)
WATERTOWN..
TUESDAY HIGH: 90 (1959) LOW: 70 (1962)
WEDNESDAY HIGH: 89 (1961) LOW: 70 (1961)
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM EDT TUESDAY FOR LEZ020-
040-041.
SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM EDT TUESDAY
FOR LOZ030.
SMALL CRAFT ADVISORY FROM 10 AM TO 8 PM EDT TUESDAY FOR
LOZ042-043.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT TUESDAY FOR
LOZ045.
&&
$$
SYNOPSIS...HITCHCOCK/WOOD
NEAR TERM...HITCHCOCK/WOOD
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...HITCHCOCK
MARINE...WOOD
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1034 PM EDT MON SEP 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL PERSIST INTO MID WEEK AND THEN MOVE OFFSHORE.
A COLD FRONT IS EXPECTED TO CROSS THE AREA ON FRIDAY. HIGH
PRESSURE AND COOLER TEMPERATURES WILL FOLLOW FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM MONDAY...ISOLATED SHOWERS FINALLY DIED WEST OF
FLORENCE BUT THERE ARE STILL SOME PATCHES OF FAIRLY DEEP CUMULUS
TUCKED UNDERNEATH THE BUILDING SUBSIDENCE INVERSION ALOFT. A
SPRINKLE OR TWO COULD STILL FALL FROM THESE IN THE FLORENCE/
DARLINGTON AREA OVER THE NEXT HOUR OR SO. SOME MARINE CUMULUS ARE
PUSHING ONSHORE IN THE MYRTLE BEACH AREA...AND A FEW MID-LEVEL
CLOUDS ARE DRIFTING SOUTH DOWN THE COAST. DESPITE ALL THIS SKY COVER
SHOULD AVERAGE OUT TO "MOSTLY CLEAR" OVERNIGHT. FOG STILL APPEARS
LIKELY TO DEVELOP MAINLY ACROSS SE NC WHERE WINDS ARE ALREADY CALM.
BASED MAINLY IN DEWPOINTS AND WINDS I HAVE NUDGED FORECAST LOW
TEMPERATURES UP ACROSS NE SOUTH CAROLINA...WITH MAINLY UPPER 60S
EXPECTED INLAND FROM THE BEACHES. PREVIOUS DISCUSSION FROM 730 PM
FOLLOWS...
FEW CHANGES ARE NEEDED TO THE FORECAST THIS EVENING. RADAR SHOWS
SHOWERS ARE BECOMING MOST ISOLATED ALONG AND WEST OF INTERSTATE 95.
LATEST HRRR MODEL RUNS SAY THESE SHOWERS SHOULD DISSIPATE IN THE
NEXT 60-90 MINUTES WITH THE LOSS OF DAYTIME HEATING. A BUILDING
SUBSIDENCE INVERSION ALOFT PLUS RATHER DRY AIR LURKING ABOVE RICH
LOW LEVEL MOISTURE 1000-1500 FEET DEEP...COMBINED WITH LIGHT WINDS
SHOULD SET THE STAGE FOR INLAND FOG AGAIN TONIGHT. I HAVE INCREASED
THE FORECAST COVERAGE OF FOG ACROSS INTERIOR SOUTHEAST NC PLUS THE
NORTHERN PORTION OF THE SC PEE DEE REGION WHERE SURFACE-TO-1000 FOOT
WINDS ARE EXPECTED TO BE LIGHTEST. FOG POTENTIAL MAY BE A LITTLE
LOWER SOUTH OF FLORENCE AND CONWAY WHERE INCREASING DISTANCE FROM
THE SURFACE HIGH WILL KEEP THE BOUNDARY LAYER A BIT MORE STIRRED UP.
PREVIOUS DISCUSSION FROM 300 PM FOLLOWS...
BEAUTIFUL AFTERNOON ONGOING ACROSS THE CAROLINAS THANKS TO AN AREA
OF HIGH PRESSURE CENTERED NEAR NEW ENGLAND...RIDGING DOWN THE EAST
COAST. TEMPS HAVE RISEN INTO THE MID/UPR 80S...WHICH COMBINED WITH
DEWPOINTS IN THE UPPER 60S HAS SPAWNED SOME AGITATED CU...FROM WHICH
A FEW ISOLATED SHOWERS HAVE DEVELOPED. SHOWERS HAVE BEEN CONFINED TO
THE WESTWARD MOVING SEA BREEZE BOUNDARY...AND HAVE CONTINUED SCHC
POP ALONG THIS BOUNDARY FOR A FEW MORE HOURS BEFORE LOSS OF DIURNAL
HEATING CAUSES ANY CONVECTION TO CEASE. AS EXPECTED...NO LIGHTNING
HAS DEVELOPED DUE TO OVERALL WEAK UPDRAFTS BEING CAPPED BY A BULGING
THERMAL INVERSION AROUND 750MB NOTED ON RUC PROXIMITY SOUNDINGS (IN
RESPONSE TO MID-LEVEL RIDGING EXPANDING TO THE WEST)...AND HAVE KEPT
RW- AS THE WX TYPE THROUGH TONIGHT.
CLOUD COVER AND SHOWERS WILL DISSIPATE QUICKLY AFTER
NIGHTFALL...ALLOWING FOR VERY GOOD RADIATIONAL COOLING TONIGHT...AND
TEMPS WILL FALL RAPIDLY AFTER DARK. AS TEMPS FALL TONIGHT...CONCERN
BECOMES HOW COOL WILL THE AREA GET...AND WHAT FOG POTENTIAL EXISTS.
WITH QUICKLY FALLING TEMPS BENEATH THE DRY COLUMN...AND WINDS LIKELY
DECOUPLING...HAVE SHOWN SOME RADIATIONAL COOLING EFFECT IN THE MIN-T
FORECAST AND HAVE UNDERCUT MOS NUMBERS TONIGHT...WITH LOW-TO-MID 60S
EXPECTED. SOME TEMPS NEAR 60 ARE POSSIBLE IN THE TYPICALLY COOLER
LOCATIONS.
AS TEMPS FALL TO THESE VALUES TONIGHT...THEY WILL EXCEED THE
CROSSOVER TEMPS...A SIGNAL NORMALLY ASSOCIATED WITH FOG POTENTIAL.
AT THE SAME TIME...RUC AND NAM BUFR SOUNDINGS SHOW FAVORABLE
LOW-LEVEL HYDROLAPSE RATES FOR FOG DEVELOPMENT...ESPECIALLY INLAND
FROM THE COAST. HAVE ADDED PATCHY/AREAS OF FOG INLAND...WHERE FOG IS
MORE LIKELY. THE COAST MAY EXPERIENCE SOME FOG AS WELL...BUT IT WILL
NOT BE AS WIDESPREAD OR DENSE AS WHAT IS EXPECTED ACROSS THE
CENTRAL/WESTERN PORTIONS OF THE CWA.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...HIGH PRESSURE ALOFT WILL REMAIN IN PLACE ON
TUESDAY. AT THE SURFACE...ATLANTIC HIGH PRESSURE WILL BE CENTERED
SOUTH OF THE CANADIAN MARITIMES AND RIDGE SW AND ALL THE WAY BACK
ACROSS THE EASTERN CAROLINAS. ON WED...THE SURFACE RIDGE WILL
BEGIN TO WEAKEN ACROSS THE SOUTHEAST UNITED STATES. THE LARGE
AREA OF HIGH PRESSURE ALOFT WILL SPLIT...TO OUR W AND TO OUR E.
THIS WILL ALLOW A TROUGH TO EVENTUALLY DIG ACROSS THE EASTERN
THIRD OF THE NATION LATE WEEK.
THE PERIOD LOOKS LIKE IT WILL BE DRY AS SUBSIDENCE AND DRY AIR...
ESPECIALLY IN THE MID LEVELS...DOMINATE. DO EXPECT SCATTERED TO
BRIEFLY BROKEN CUMULUS TO BUILD UP EACH AFTERNOON...BUT THIS
MOISTURE WILL BE CAPPED BELOW 10 KFT...KEEPING ANY BUILDUPS RATHER
SHALLOW. DAYTIME TEMPS WILL BE SLIGHTLY ABOVE NORMAL...COMMONLY IN
THE UPPER 80S TO LOWER 90S. THE SEABREEZE IS EXPECTED TO MAKE
GOOD INLAND PROGRESS GIVEN THE DEEP SYNOPTIC EASTERLY FLOW. THIS
WILL REDUCE HIGHS ALONG AND NEAR THE COAST BY ABOUT A CATEGORY AS
COMPARED TO LOCATIONS MUCH FURTHER INLAND. LOW TEMPS WILL BE
RATHER TYPICAL FOR MID SEPTEMBER...UPPER 60S AND LOWER 70S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 3 PM MONDAY...A RELATIVELY FAST MOVING/PROGRESSIVE TROUGH
WILL BE THE MAIN FEATURE FOR THE EXTENDED PERIOD OF THE FORECAST.
MEDIUM RANGE GUIDANCE HAS INCREASED THE TIMING FOR THE ASSOCIATED
FRONT WHICH NOW APPEARS TO MOVE ACROSS THE AREA FRIDAY MORNING.
THE LATEST UPDATE INCLUDES AN INCREASE OF POPS FOR THE THURSDAY
NIGHT/FRIDAY MORNING TIME PERIOD WITH A SLIGHT DOWNTREND FOR
FRIDAY`S POPS. IT APPEARS GUIDANCE IS ALSO CONVERGING ON A
SOLUTION OF A MORE SOUTHERN EXTENT OF THE FRONT FOR THE WEEKEND
INTO EARLY NEXT WEEK...SETTING UP A COOL AND DRY WEEKEND. DO NOT
EXPECT IDEAL RADIATIONAL CONDITIONS FOR ANY OVERNIGHT PERIOD BUT
SUNDAY MORNING APPEARS TO BE THE COOLEST WITH THE LIGHTEST WINDS.
WE HAVE LOWS IN THE LOWER 50S EXTREME NORTHWESTERN AREAS WITH NEAR
60 ALONG THE COAST. MOST HIGHS WILL BE IN THE UPPER 70S TO LOWER
80S FOR THE WEEKEND.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 00Z...EXPECT MVFR/IFR/LIFR DUE TO AREAS OF FOG/STRATUS LATE
OVERNIGHT INTO THE EARLY MORNING HOURS ON TUESDAY. OTHERWISE EXPECT
VFR THROUGH THE TAF PERIOD.
A COUPLE OF LIGHT SHOWERS CONTINUE TO PROGRESS WESTWARD ACROSS
PORTIONS OF THE AREA THIS EVENING...THOUGH HAVE NOT/NOR EXPECT ANY
RESTRICTIONS AS A RESULT. FOR THE REST OF THIS EVENING...VFR WILL
PREVAIL WITH WINDS BECOMING LIGHT AND VARIABLE INTO THE EVENING
HOURS WITH FEW/SCT LINGERING CLOUDS. INTO THE OVERNIGHT
HOURS...TIME-HEIGHT ANALYSIS AND FCST SOUNDINGS CONTINUE TO SUPPORT
AREAS OF FOG/STRATUS DEVELOPMENT...ESPECIALLY INLAND...AS AN IDEAL
RADIATIONAL COOLING SETUP IS IN PLACE ALONG WITH A DEEP LOW-LEVEL
MOISTURE SOURCE. GIVEN DIFFERENTIAL WIND FIELDS BETWEEN THE TWO
INLAND SITES...ATTM ANTICIPATE KFLO TO EXPERIENCE MVFR/IFR DUE TO
POSSIBLE STRATUS LAYER AND REDUCED VISIBILITIES. WINDS WILL BE
NEARLY CALM AT KLBT...THUS HAVE OPTED TO INTRODUCE POSSIBLE IFR/LIFR
DUE TO FOG...WHILE NOT COMPLETELY RULING OUT FEW/SCT STRATUS AS
WELL. AS FOR THE COAST...CONFIDENCE IS LOW REGARDING FOG
DEVELOPMENT...THUS HAVE KEPT TEMPO MVFR POSSIBILITY.
AFTER DAYBREAK...CONDITIONS WILL QUICKLY IMPROVE TO VFR AND CONTINUE
THROUGHOUT THE REMAINDER OF THE VALID TAF PERIOD WITH FEW/SCT
CLOUDS. LIGHT NORTHEAST WINDS IN THE MORNING WILL BECOME
EAST-SOUTHEAST BY THE AFTERNOON HOURS...WITH SUSTAINED WINDS AOB 10
KTS...WITH THE HIGHER WINDS ALONG THE COAST.
EXTENDED OUTLOOK...EARLY MORNING MVFR/IFR VSBYS POSSIBLE THROUGH
THURSDAY...MOST LIKELY AT KFLO/KLBT. CHANCE OF SHOWERS/T-STORMS ON
FRIDAY ASSOCIATED WITH A COLD FRONT. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM MONDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS...
CHANGES TO THE MARINE FORECAST INCLUDE BACKING WIND DIRECTIONS
AROUND MORE EASTERLY...AND KEEPING WIND SPEEDS JUST A BIT STRONGER
THAN ORIGINALLY FORECAST. SEAS CONTINUE TO AVERAGE 2 FEET ALTHOUGH
THERE ARE LIKELY SOME 3-FOOTERS LURKING JUST OUTSIDE 20 MILES
DISTANCE FROM SHORE. THE LONG PERIOD (9-10 SECOND) SOUTHEAST SWELL
OF THE PAST FEW DAYS IS SHORTENING ITS PERIODS TO AROUND 7 SECONDS
AND IS MERGING WITH THE LOCALLY GENERATED WIND WAVES. A FEW SHOWERS
EAST OF GEORGETOWN COULD CONTINUE FOR THE NEXT FEW HOURS...BUT
GENERALLY DRY WEATHER IS EXPECTED OTHERWISE. PREVIOUS DISCUSSION
FROM 300 PM FOLLOWS...
HIGH PRESSURE CENTERED ACROSS NEW ENGLAND IS RIDGING DOWN THE COAST
TODAY...WHICH HAS KEPT A WEAK PRESSURE GRADIENT ACROSS THE WATERS.
WINDS HAVE BEEN QUITE LIGHT IN RESPONSE TO THIS GRADIENT...10 KTS OR
LESS AT THE LOCAL BUOYS...AND THESE SPEEDS WILL PERSIST TONIGHT EVEN
AS DIRECTION BACKS MORE TO THE NE. THE SEA SPECTRUM WILL REMAIN
COMPRISED OF A LOW-AMPLITUDE E/NE WIND CHOP AND A 2 FT SE
SWELL...CREATING WAVE HEIGHTS OF 2-3 FT THROUGH TONIGHT...BUT ONLY
AROUND 1-2 FT NEAR SHORE OF BRUNSWICK COUNTY DUE TO WAVE SHADOWING.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...HIGH PRESSURE WILL BE CENTERED WELL N OF THE
WATERS THROUGH THE PERIOD. WINDS WILL STILL BE FROM THE NE ON
TUE...VEERING SLIGHTLY TO ENE OR E TUE AFTERNOON AND EVE AND THEN
BACK TO A MORE NE DIRECTION OVERNIGHT TUE. NE WINDS WED MORNING
WILL VEER TO E OR ESE DURING THE DAY...BECOMING LIGHT AND VARIABLE
WED NIGHT. THE GRADIENT WILL BE TIGHTEST ON TUE...SUSTAINED WIND
SPEEDS UP TO 15 KT. THEREAFTER...WINDS WILL BE 10 KT OR LESS. WIND
SPEEDS WILL BE COMPARATIVELY HIGHER ACROSS THE NEAR SHORE WATERS
EACH AFTERNOON DUE TO SEABREEZE INFLUENCES. SEAS WILL BE 2 TO 3
FT...BUT THERE WILL BE SOME 4 FT SEAS TUE AFTERNOON WHEN THE
GRADIENT IS EXPECTED TO BE TIGHTEST.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 3 PM MONDAY...THE MAIN FEATURE WILL BE THE WIND SHIFT
ASSOCIATED WITH THE FRONT MOVING ACROSS THE WATERS FRIDAY MORNING.
WINDS WILL SHIFT FROM A MODEST PRE-FRONTAL SOUTHWESTERLY FLOW OF
10-15 KNOTS...MOSTLY HOVERING AROUND THE LOWER END OF THE RANGE TO
NORTH/NORTHEAST BY MIDDAY FRIDAY. SPEEDS WILL INCREASE TO REACH A
MAX OF 15-20 KNOTS EARLY SATURDAY. THE NORTHEASTERLY FLOW WILL BE
RELATIVELY STABLE AT 15-20 KNOTS FOR THE REMAINDER OF SATURDAY BUT
SPEEDS MAY DIMINISH TOWARD THE LOWER END OF THE RANGE. SIGNIFICANT
SEAS WILL INCREASE FROM 1-2 FEET EARLY TO 2-4 FEET BY THE END OF THE
PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW/TRA
SHORT TERM...RJD
LONG TERM...SHK
AVIATION..SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
730 PM EDT MON SEP 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL PERSIST INTO MID WEEK AND THEN MOVE OFFSHORE.
A COLD FRONT IS EXPECTED TO CROSS THE AREA ON FRIDAY. HIGH
PRESSURE AND COOLER TEMPERATURES WILL FOLLOW FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 730 PM MONDAY...FEW CHANGES ARE NEEDED TO THE FORECAST THIS
EVENING. RADAR SHOWS SHOWERS ARE BECOMING MOST ISOLATED ALONG AND
WEST OF INTERSTATE 95. LATEST HRRR MODEL RUNS SAY THESE SHOWERS
SHOULD DISSIPATE IN THE NEXT 60-90 MINUTES WITH THE LOSS OF DAYTIME
HEATING. A BUILDING SUBSIDENCE INVERSION ALOFT PLUS RATHER DRY AIR
LURKING ABOVE RICH LOW LEVEL MOISTURE 1000-1500 FEET DEEP...COMBINED
WITH LIGHT WINDS SHOULD SET THE STAGE FOR INLAND FOG AGAIN TONIGHT.
I HAVE INCREASED THE FORECAST COVERAGE OF FOG ACROSS INTERIOR
SOUTHEAST NC PLUS THE NORTHERN PORTION OF THE SC PEE DEE REGION
WHERE SURFACE-TO-1000 FOOT WINDS ARE EXPECTED TO BE LIGHTEST. FOG
POTENTIAL MAY BE A LITTLE LOWER SOUTH OF FLORENCE AND CONWAY WHERE
INCREASING DISTANCE FROM THE SURFACE HIGH WILL KEEP THE BOUNDARY
LAYER A BIT MORE STIRRED UP. PREVIOUS DISCUSSION FROM 300 PM
FOLLOWS...
BEAUTIFUL AFTERNOON ONGOING ACROSS THE CAROLINAS THANKS TO AN AREA
OF HIGH PRESSURE CENTERED NEAR NEW ENGLAND...RIDGING DOWN THE EAST
COAST. TEMPS HAVE RISEN INTO THE MID/UPR 80S...WHICH COMBINED WITH
DEWPOINTS IN THE UPPER 60S HAS SPAWNED SOME AGITATED CU...FROM WHICH
A FEW ISOLATED SHOWERS HAVE DEVELOPED. SHOWERS HAVE BEEN CONFINED TO
THE WESTWARD MOVING SEA BREEZE BOUNDARY...AND HAVE CONTINUED SCHC
POP ALONG THIS BOUNDARY FOR A FEW MORE HOURS BEFORE LOSS OF DIURNAL
HEATING CAUSES ANY CONVECTION TO CEASE. AS EXPECTED...NO LIGHTNING
HAS DEVELOPED DUE TO OVERALL WEAK UPDRAFTS BEING CAPPED BY A BULGING
THERMAL INVERSION AROUND 750MB NOTED ON RUC PROXIMITY SOUNDINGS (IN
RESPONSE TO MID-LEVEL RIDGING EXPANDING TO THE WEST)...AND HAVE KEPT
RW- AS THE WX TYPE THROUGH TONIGHT.
CLOUD COVER AND SHOWERS WILL DISSIPATE QUICKLY AFTER
NIGHTFALL...ALLOWING FOR VERY GOOD RADIATIONAL COOLING TONIGHT...AND
TEMPS WILL FALL RAPIDLY AFTER DARK. AS TEMPS FALL TONIGHT...CONCERN
BECOMES HOW COOL WILL THE AREA GET...AND WHAT FOG POTENTIAL EXISTS.
WITH QUICKLY FALLING TEMPS BENEATH THE DRY COLUMN...AND WINDS LIKELY
DECOUPLING...HAVE SHOWN SOME RADIATIONAL COOLING EFFECT IN THE MIN-T
FORECAST AND HAVE UNDERCUT MOS NUMBERS TONIGHT...WITH LOW-TO-MID 60S
EXPECTED. SOME TEMPS NEAR 60 ARE POSSIBLE IN THE TYPICALLY COOLER
LOCATIONS.
AS TEMPS FALL TO THESE VALUES TONIGHT...THEY WILL EXCEED THE
CROSSOVER TEMPS...A SIGNAL NORMALLY ASSOCIATED WITH FOG POTENTIAL.
AT THE SAME TIME...RUC AND NAM BUFR SOUNDINGS SHOW FAVORABLE
LOW-LEVEL HYDROLAPSE RATES FOR FOG DEVELOPMENT...ESPECIALLY INLAND
FROM THE COAST. HAVE ADDED PATCHY/AREAS OF FOG INLAND...WHERE FOG IS
MORE LIKELY. THE COAST MAY EXPERIENCE SOME FOG AS WELL...BUT IT WILL
NOT BE AS WIDESPREAD OR DENSE AS WHAT IS EXPECTED ACROSS THE
CENTRAL/WESTERN PORTIONS OF THE CWA.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...HIGH PRESSURE ALOFT WILL REMAIN IN PLACE ON
TUESDAY. AT THE SURFACE...ATLANTIC HIGH PRESSURE WILL BE CENTERED
SOUTH OF THE CANADIAN MARITIMES AND RIDGE SW AND ALL THE WAY BACK
ACROSS THE EASTERN CAROLINAS. ON WED...THE SURFACE RIDGE WILL
BEGIN TO WEAKEN ACROSS THE SOUTHEAST UNITED STATES. THE LARGE
AREA OF HIGH PRESSURE ALOFT WILL SPLIT...TO OUR W AND TO OUR E.
THIS WILL ALLOW A TROUGH TO EVENTUALLY DIG ACROSS THE EASTERN
THIRD OF THE NATION LATE WEEK.
THE PERIOD LOOKS LIKE IT WILL BE DRY AS SUBSIDENCE AND DRY AIR...
ESPECIALLY IN THE MID LEVELS...DOMINATE. DO EXPECT SCATTERED TO
BRIEFLY BROKEN CUMULUS TO BUILD UP EACH AFTERNOON...BUT THIS
MOISTURE WILL BE CAPPED BELOW 10 KFT...KEEPING ANY BUILDUPS RATHER
SHALLOW. DAYTIME TEMPS WILL BE SLIGHTLY ABOVE NORMAL...COMMONLY IN
THE UPPER 80S TO LOWER 90S. THE SEABREEZE IS EXPECTED TO MAKE
GOOD INLAND PROGRESS GIVEN THE DEEP SYNOPTIC EASTERLY FLOW. THIS
WILL REDUCE HIGHS ALONG AND NEAR THE COAST BY ABOUT A CATEGORY AS
COMPARED TO LOCATIONS MUCH FURTHER INLAND. LOW TEMPS WILL BE
RATHER TYPICAL FOR MID SEPTEMBER...UPPER 60S AND LOWER 70S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 3 PM MONDAY...A RELATIVELY FAST MOVING/PROGRESSIVE TROUGH
WILL BE THE MAIN FEATURE FOR THE EXTENDED PERIOD OF THE FORECAST.
MEDIUM RANGE GUIDANCE HAS INCREASED THE TIMING FOR THE ASSOCIATED
FRONT WHICH NOW APPEARS TO MOVE ACROSS THE AREA FRIDAY MORNING.
THE LATEST UPDATE INCLUDES AN INCREASE OF POPS FOR THE THURSDAY
NIGHT/FRIDAY MORNING TIME PERIOD WITH A SLIGHT DOWNTREND FOR
FRIDAY`S POPS. IT APPEARS GUIDANCE IS ALSO CONVERGING ON A
SOLUTION OF A MORE SOUTHERN EXTENT OF THE FRONT FOR THE WEEKEND
INTO EARLY NEXT WEEK...SETTING UP A COOL AND DRY WEEKEND. DO NOT
EXPECT IDEAL RADIATIONAL CONDITIONS FOR ANY OVERNIGHT PERIOD BUT
SUNDAY MORNING APPEARS TO BE THE COOLEST WITH THE LIGHTEST WINDS.
WE HAVE LOWS IN THE LOWER 50S EXTREME NORTHWESTERN AREAS WITH NEAR
60 ALONG THE COAST. MOST HIGHS WILL BE IN THE UPPER 70S TO LOWER
80S FOR THE WEEKEND.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 00Z...EXPECT MVFR/IFR/LIFR DUE TO AREAS OF FOG/STRATUS LATE
OVERNIGHT INTO THE EARLY MORNING HOURS ON TUESDAY. OTHERWISE EXPECT
VFR THROUGH THE TAF PERIOD.
A COUPLE OF LIGHT SHOWERS CONTINUE TO PROGRESS WESTWARD ACROSS
PORTIONS OF THE AREA THIS EVENING...THOUGH HAVE NOT/NOR EXPECT ANY
RESTRICTIONS AS A RESULT. FOR THE REST OF THIS EVENING...VFR WILL
PREVAIL WITH WINDS BECOMING LIGHT AND VARIABLE INTO THE EVENING
HOURS WITH FEW/SCT LINGERING CLOUDS. INTO THE OVERNIGHT
HOURS...TIME-HEIGHT ANALYSIS AND FCST SOUNDINGS CONTINUE TO SUPPORT
AREAS OF FOG/STRATUS DEVELOPMENT...ESPECIALLY INLAND...AS AN IDEAL
RADIATIONAL COOLING SETUP IS IN PLACE ALONG WITH A DEEP LOW-LEVEL
MOISTURE SOURCE. GIVEN DIFFERENTIAL WIND FIELDS BETWEEN THE TWO
INLAND SITES...ATTM ANTICIPATE KFLO TO EXPERIENCE MVFR/IFR DUE TO
POSSIBLE STRATUS LAYER AND REDUCED VISIBILITIES. WINDS WILL BE
NEARLY CALM AT KLBT...THUS HAVE OPTED TO INTRODUCE POSSIBLE IFR/LIFR
DUE TO FOG...WHILE NOT COMPLETELY RULING OUT FEW/SCT STRATUS AS
WELL. AS FOR THE COAST...CONFIDENCE IS LOW REGARDING FOG
DEVELOPMENT...THUS HAVE KEPT TEMPO MVFR POSSIBILITY.
AFTER DAYBREAK...CONDITIONS WILL QUICKLY IMPROVE TO VFR AND CONTINUE
THROUGHOUT THE REMAINDER OF THE VALID TAF PERIOD WITH FEW/SCT
CLOUDS. LIGHT NORTHEAST WINDS IN THE MORNING WILL BECOME
EAST-SOUTHEAST BY THE AFTERNOON HOURS...WITH SUSTAINED WINDS AOB 10
KTS...WITH THE HIGHER WINDS ALONG THE COAST.
EXTENDED OUTLOOK...EARLY MORNING MVFR/IFR VSBYS POSSIBLE THROUGH
THURSDAY...MOST LIKELY AT KFLO/KLBT. CHANCE OF SHOWERS/T-STORMS ON
FRIDAY ASSOCIATED WITH A COLD FRONT. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 730 PM MONDAY...CHANGES TO THE MARINE FORECAST INCLUDE BACKING
WIND DIRECTIONS AROUND MORE EASTERLY...AND KEEPING WIND SPEEDS JUST
A BIT STRONGER THAN ORIGINALLY FORECAST. SEAS CONTINUE TO AVERAGE 2
FEET ALTHOUGH THERE ARE LIKELY SOME 3-FOOTERS LURKING JUST OUTSIDE
20 MILES DISTANCE FROM SHORE. THE LONG PERIOD (9-10 SECOND)
SOUTHEAST SWELL OF THE PAST FEW DAYS IS SHORTENING ITS PERIODS TO
AROUND 7 SECONDS AND IS MERGING WITH THE LOCALLY GENERATED WIND
WAVES. A FEW SHOWERS EAST OF GEORGETOWN COULD CONTINUE FOR THE NEXT
FEW HOURS...BUT GENERALLY DRY WEATHER IS EXPECTED OTHERWISE.
PREVIOUS DISCUSSION FROM 300 PM FOLLOWS...
HIGH PRESSURE CENTERED ACROSS NEW ENGLAND IS RIDGING DOWN THE COAST
TODAY...WHICH HAS KEPT A WEAK PRESSURE GRADIENT ACROSS THE WATERS.
WINDS HAVE BEEN QUITE LIGHT IN RESPONSE TO THIS GRADIENT...10 KTS OR
LESS AT THE LOCAL BUOYS...AND THESE SPEEDS WILL PERSIST TONIGHT EVEN
AS DIRECTION BACKS MORE TO THE NE. THE SEA SPECTRUM WILL REMAIN
COMPRISED OF A LOW-AMPLITUDE E/NE WIND CHOP AND A 2 FT SE
SWELL...CREATING WAVE HEIGHTS OF 2-3 FT THROUGH TONIGHT...BUT ONLY
AROUND 1-2 FT NEAR SHORE OF BRUNSWICK COUNTY DUE TO WAVE SHADOWING.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...HIGH PRESSURE WILL BE CENTERED WELL N OF THE
WATERS THROUGH THE PERIOD. WINDS WILL STILL BE FROM THE NE ON
TUE...VEERING SLIGHTLY TO ENE OR E TUE AFTERNOON AND EVE AND THEN
BACK TO A MORE NE DIRECTION OVERNIGHT TUE. NE WINDS WED MORNING
WILL VEER TO E OR ESE DURING THE DAY...BECOMING LIGHT AND VARIABLE
WED NIGHT. THE GRADIENT WILL BE TIGHTEST ON TUE...SUSTAINED WIND
SPEEDS UP TO 15 KT. THEREAFTER...WINDS WILL BE 10 KT OR LESS. WIND
SPEEDS WILL BE COMPARATIVELY HIGHER ACROSS THE NEAR SHORE WATERS
EACH AFTERNOON DUE TO SEABREEZE INFLUENCES. SEAS WILL BE 2 TO 3
FT...BUT THERE WILL BE SOME 4 FT SEAS TUE AFTERNOON WHEN THE
GRADIENT IS EXPECTED TO BE TIGHTEST.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 3 PM MONDAY...THE MAIN FEATURE WILL BE THE WIND SHIFT
ASSOCIATED WITH THE FRONT MOVING ACROSS THE WATERS FRIDAY MORNING.
WINDS WILL SHIFT FROM A MODEST PRE-FRONTAL SOUTHWESTERLY FLOW OF
10-15 KNOTS...MOSTLY HOVERING AROUND THE LOWER END OF THE RANGE TO
NORTH/NORTHEAST BY MIDDAY FRIDAY. SPEEDS WILL INCREASE TO REACH A
MAX OF 15-20 KNOTS EARLY SATURDAY. THE NORTHEASTERLY FLOW WILL BE
RELATIVELY STABLE AT 15-20 KNOTS FOR THE REMAINDER OF SATURDAY BUT
SPEEDS MAY DIMINISH TOWARD THE LOWER END OF THE RANGE. SIGNIFICANT
SEAS WILL INCREASE FROM 1-2 FEET EARLY TO 2-4 FEET BY THE END OF THE
PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW/TRA
SHORT TERM...RJD
LONG TERM...SHK
AVIATION..SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
205 PM EDT SUN SEP 8 2013
.SYNOPSIS...
A MOSTLY DRY COLD FRONT...APPROACHING FROM THE NORTH...WEAKENS AS IT
SLOWLY MOVES THROUGH THE REGION TONIGHT AND MONDAY. WEAK HIGH
PRESSURE BUILDS IN BEHIND THE FRONT. ANOTHER COLD FRONT MOVES
THROUGH THE AREA LATE IN THE WORK WEEK.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
AS OF 1045 AM SUNDAY...
REST OF TODAY: THE MOST STRIKING CHANGE TO THE FORECAST WILL BE AN
INCREASE IN THE AMOUNT OF SUNSHINE... PARTICULARLY OUTSIDE OF THE
TRIAD REGION. LATEST SURFACE MAP SHOWS A WEAK PRESSURE/WIND PATTERN
OVER THE REGION... FEATURING A SURFACE TROUGH THROUGH THE PIEDMONT
AND YESTERDAY`S HIGH PRESSURE AREA SLIDING FURTHER TO OUR SW. THE
SURFACE COLD FRONT NOW STRETCHING FROM AROUND BOSTON TO JUST NORTH
OF THE OH RIVER... MAKING GOOD SOUTHWARD PROGRESS AS IT IS PUSHED BY
COOL DENSE HIGH PRESSURE TO THE NORTH. WIDESPREAD MID CLOUDS TO OUR
NORTH EARLIER THIS MORNING... ACROSS WV/VA/MD/DE/NJ/PA SHORTLY
BEFORE DAYBREAK... HAVE ALMOST COMPLETELY VANISHED AS THEY
ENCOUNTERED THE DRY/STABLE AIR AND DIFFLUENT FLOW OVER NC. RAP MODEL
SOUNDINGS SHOW A FEW MID CLOUDS DRIFTING OVER THE FORECAST AREA THIS
AFTERNOON... BUT THIS APPEARS TO BE SHORT-LIVED WITH MAINLY
SCATTERED CLOUDS... AND MOST OF THE AREA SHOULD SEE MOSTLY SUNNY
SKIES FOR THE MAJORITY OF THE DAY. THE EXCEPTION WILL BE IN THE NW
CWA WHERE MODELS... UPSTREAM SOUNDINGS... AND SATELLITE TRENDS
SUGGEST THAT THE COVERAGE OF MID CLOUDS WILL BE A LITTLE BETTER...
LEADING TO PARTLY CLOUDY SKIES. SEVERAL CONVECTION-ALLOWING MODELS
DEPICT A FEW SPRINKLES MAKING IT INTO THE FOOTHILLS LATE THIS
AFTERNOON... BUT BASED ON THE GENERALLY DOWNSLOPE FLOW AND LACK OF
LOW LEVEL MOISTURE... BELIEVE THESE WILL HOLD JUST NW OF THE CWA.
THICKNESSES AND STATISTICAL GUIDANCE SUPPORT FORECAST HIGHS OF
86-91. -GIH
TONIGHT AND MONDAY:
THE AFOREMENTIONED COLD FRONT WILL PROGRESS SOUTHWARD INTO CENTRAL
NC TONIGHT WILL LITTLE FANFARE... OTHER THAN AN INCREASE IN CLOUD
COVER. THE FRONT IS EXPECTED TO WEAKEN AS IT MOVES THROUGH THE AREA
TONIGHT... BEFORE IT STALLS/DISSIPATES NEAR THE NC/SC BORDER ON
MONDAY. SURFACE HIGH PRESSURE WILL BUILD INTO THE AREA BEHIND THE
FRONT. HOWEVER... AS THE SURFACE HIGH CENTERED OVER THE NORTHERN
MID-ATLANTIC/NORTHEASTERN U.S. MONDAY MORNING SHIFTS EASTWARD AND
OFFSHORE ON MONDAY AFTERNOON... A LIGHT EASTERLY LOW LEVEL FLOW WILL
DEVELOP ACROSS CENTRAL NC. THIS WILL ALLOW LOW LEVEL MOISTURE TO
INCREASE... ALONG WITH POSSIBLY A FEW SHOWERS ACROSS OUR COASTAL
PLAIN COUNTIES IN THE AFTERNOON. HOWEVER... GIVEN INSTABILITY WILL
REMAIN WEAK STILL... WHILE MID LEVEL TEMPS ACTUALLY INCREASE A BIT
AS THE AFOREMENTIONED MID LEVEL RIDGES BEGINS TO BUILD EASTWARD AND
EXTENDS INTO OUR AREA... WILL ONLY KEEP A SLIGHT CHANCE OF SHOWERS
IN THE FORECAST ALONG AND TO THE EAST OF THE I-95 CORRIDOR.
LOW TEMPS MONDAY MORNING ARE EXPECTED TO BE IN THE MID TO UPPER
60S... THANKS TO THE INCREASE IN CLOUD COVER. HIGH TEMPS ON MONDAY
WILL BE TEMPERED BACK A BIT WITH THE EASTERLY LOW LEVEL FLOW. THIS
YIELDS HIGH TEMPS IN THE MID TO UPPER 80S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 205 PM SUNDAY...
UPPER LEVEL RIDGING WILL EXPAND OVER THE SOUTHEAST US
TUESDAY...WHILE A WEAK SURFACE RIDGE EXTENDS ACROSS THE AREA FROM
THE NORTHEAST. WARMING MID-LEVELS AND LARGE SCALE SUBSIDENCE..ALONG
WITH WEAK INSTABILITY...WILL LIMIT CONVECTIVE POTENTIAL AND TUESDAY
SHOULD BE ANOTHER DRY DAY. THE UPPER RIDGE WILL BEGIN TO WEAKEN
WEDNESDAY AS HEIGHTS BEGIN TO FALL OVER THE GREAT LAKES REGION AND A
LINGERING SHEAR AXIS OFF THE SOUTHEAST US COAST DRIFTS NORTHWARD.
AS SUCH...CONVECTION SHOULD BE LESS INHIBITED OVER THE
MOUNTAINS...LEAVING A SLIGHT CHANCE OF A SHOWER DRIFTING INTO THE
NORTHWEST PIEDMONT. LOW LEVEL THICKNESSES AROUND 1405M
TUESDAY/WEDNESDAY MORNING AND 850MB TEMPS APPROACHING 17-18C SUPPORT
HIGHS IN THE 87-90 RANGE EACH DAY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 205 PM SUNDAY...
THURSDAY...
HEIGHTS ALOFT WILL LOWER FURTHER ON THURSDAY AS A COLD FRONT MOVES
THROUGH THE MIDWEST STATES. MEANWHILE...MODELS CONTINUE TO SHOW THE
SHEAR AXIS OFF THE SOUTHEAST US COAST DRIFTING BACK TOWARD THE SC
COAST BEFORE BECOMING ABSORBED BY THE LARGER SCALE TROUGH. AT THIS
TIME...NEITHER THE GFS OR ECWMF SHOW MUCH IMPACT OVER EASTERN
NC...KEEPING AN AXIS OF 2 INCH PLUS PW OFFSHORE.
INSTEAD...CONVECTION SHOULD BE FOCUSED OVER WESTERN NC WHERE
SCATTERED SHOWERS AND STORMS SHOULD BE ABLE TO PROGRESS EAST WITH A
STRONGER LEE TROUGH AND WESTERLY STEERING FLOW. WILL INDICATE A
CHANCE INT HE FAR NORTHWEST PIEDMONT AND SLIGHT CHANCE EAST TOWARD
THE TRIANGLE. HIGHS IN THE UPPER 80S TO AROUND 90 ONCE AGAIN.
THURSDAY NIGHT THROUGH SUNDAY...
MEDIUM RANGE MODELS SHOW BETTER LARGE SCALE CONSISTENCY AND
AGREEMENT ON THE COLD FRONT OVER THE MIDWEST MOVING THROUGH CENTRAL
NC THURSDAY NIGHT AND FRIDAY. THE FRONT WILL BRING A LITTLE
MOISTURE WITH IT...WITH UPSTREAM PW OVER 1.75 INCHES...BUT WESTERLY
FLOW AHEAD OF THE FRONT WILL LIMIT ADDITIONAL MOISTURE TRANSPORT. WE
EXPECT JUST SCATTERED SHOWERS THURSDAY NIGHT AND EARLY FRIDAY...WITH
A FEW ISOLATED STORMS POSSIBLE ACROSS THE SOUTH ON FRIDAY BASED ON
THE SLIGHTLY SLOWER ECMWF FRONTAL PASSAGE.
BY SATURDAY...A MODERATELY STRONG CANADIAN HIGH IS FORECAST TO BUILD
ACROSS THE GREAT LAKES TOWARD THE MID-ATLANTIC STATES. LOW-LEVEL
THICKNESSES ARE FORECAST TO DROP RATHER DRAMATICALLY BEHIND THE
FRONT...WITH 1365-1375M POSSIBLE BY SATURDAY/SUNDAY MORNING. THESE
VALUES WOULD SUPPORT BELOW NORMAL TEMPS...WITH HIGHS IN THE MID TO
UPPER 70S AND LOWS IN THE LOW TO MID 50S.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 110 PM SUNDAY...
VFR CONDITIONS WILL DOMINATE INTO MONDAY AFTERNOON. HIGH PRESSURE
OVER THE REGION WILL PUSH FARTHER TO OUR SOUTHWEST WHILE A SURFACE
TROUGH SITS OVER CENTRAL NC. A MOSTLY DRY COLD FRONT LOCATED ACROSS
SRN IN/SRN OH ACROSS MD WILL PUSH STEADILY SOUTHWARD THROUGH
TONIGHT... DROPPING THROUGH NC LATE TONIGHT. ONLY SCATTERED TO
BROKEN VFR CLOUDS BASED ABOVE 5 KFT AGL ARE EXPECTED AHEAD OF AND
JUST BEHIND THIS FRONT LATE TONIGHT INTO EARLY MONDAY MORNING. LIGHT
AND VARIABLE WINDS WILL SWING AROUND TO NORTHEASTERLY BETWEEN 07Z
THROUGH 12Z NORTH-TO-SOUTH AND SPEEDS WILL PICK UP TO 7-10 KTS JUST
BEHIND THE FRONT... WITH A FEW GUSTS FROM THE NE TO 12-14 KTS
POSSIBLE. THERE IS A SMALL CHANCE OF MVFR FOG LASTING FOR JUST AN
HOUR OR SO JUST AHEAD OF THE FRONT LATE TONIGHT... 06Z-12Z.
LOOKING BEYOND 18Z MONDAY... HIGH CONFIDENCE IN VFR CONDITIONS
THROUGH THURSDAY NIGHT... AS WEAK HIGH PRESSURE WILL STRETCH ACROSS
THE AREA THROUGH MID WEEK. PATCHY BRIEF MVFR FOG IS POSSIBLE WITHIN
AN HOUR OF DAYBREAK EACH MORNING TUESDAY THROUGH THURSDAY. ANOTHER
COLD FRONT WILL APPROACH FROM THE NW LATE FRIDAY... AND MAY BRING A
FEW SHOWERS AND STORMS FRIDAY AFTERNOON. -GIH
24 HOUR TAF PERIOD:
VFR CONDITIONS ARE GENERALLY EXPECTED TO PREVAIL ACROSS THE AREA AS
DRY COLD FRONT APPROACHES THE REGION FROM THE NORTH TODAY. THE COLD
FRONT IS EXPECTED TO SLOWLY CROSS CENTRAL NC TONIGHT. IF ANY MVFR
FOG DEVELOPS THIS MORNING AT KRWI IT WILL MIX OUT QUICKLY WITH
DIURNAL MIXING AND SHOULD BE GONE BY 12Z AT THE LATEST. OTHERWISE...
WE WILL SEE MID AND HIGH LEVEL CLOUD COVER ON THE INCREASE THIS
MORNING AS A WEAK DISTURBANCE ALOFT MOVES ACROSS THE AREA. THE
AFOREMENTIONED SURFACE FRONT IS NOT EXPECTED TO MOVE INTO THE AREA
UNTIL LATE TONIGHT. HOWEVER... OUTSIDE OF AN INCREASE IN VFR
CLOUDS... THE FRONT WILL COME THROUGH WITH LITTLE FANFARE AND STALL
NEAR THE NC/SC BORDER AROUND 12Z MONDAY.
OUTLOOK:
PRE-DAWN/MORNING SUB-VFR CONDITIONS WILL BE POSSIBLE EACH MORNING...
ALTHOUGH CONFIDENCE IS VERY LOW FOR ANY WIDESPREAD SUB-VFR
CONDITIONS. OTHERWISE... VFR CONDITIONS ARE EXPECTED... WITH
GENERALLY DRY CONDITIONS (VERY SMALL CHANCE OF A AFTERNOON/EVENING
SHOWER OR STORM EACH DAY AS WELL... BEST CHANCE ON WEDNESDAY AND
THURSDAY AT KGSO/KINT).
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...HARTFIELD/BSD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1045 AM EDT SUN SEP 8 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA WILL WEAKEN AND SHIFT TO OUR SOUTH
TODAY. A DRY COLD FRONT WILL APPROACH FROM THE NORTH LATE TODAY...
THEN MOVE SOUTHWARD THROUGH NC TONIGHT. ANOTHER HIGH PRESSURE AREA
WILL BUILD INTO THE REGION FROM THE NORTH FOR MONDAY AND TUESDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 1045 AM SUNDAY...
REST OF TODAY: THE MOST STRIKING CHANGE TO THE FORECAST WILL BE AN
INCREASE IN THE AMOUNT OF SUNSHINE... PARTICULARLY OUTSIDE OF THE
TRIAD REGION. LATEST SURFACE MAP SHOWS A WEAK PRESSURE/WIND PATTERN
OVER THE REGION... FEATURING A SURFACE TROUGH THROUGH THE PIEDMONT
AND YESTERDAY`S HIGH PRESSURE AREA SLIDING FURTHER TO OUR SW. THE
SURFACE COLD FRONT NOW STRETCHING FROM AROUND BOSTON TO JUST NORTH
OF THE OH RIVER... MAKING GOOD SOUTHWARD PROGRESS AS IT IS PUSHED BY
COOL DENSE HIGH PRESSURE TO THE NORTH. WIDESPREAD MID CLOUDS TO OUR
NORTH EARLIER THIS MORNING... ACROSS WV/VA/MD/DE/NJ/PA SHORTLY
BEFORE DAYBREAK... HAVE ALMOST COMPLETELY VANISHED AS THEY
ENCOUNTERED THE DRY/STABLE AIR AND DIFFLUENT FLOW OVER NC. RAP MODEL
SOUNDINGS SHOW A FEW MID CLOUDS DRIFTING OVER THE FORECAST AREA THIS
AFTERNOON... BUT THIS APPEARS TO BE SHORT-LIVED WITH MAINLY
SCATTERED CLOUDS... AND MOST OF THE AREA SHOULD SEE MOSTLY SUNNY
SKIES FOR THE MAJORITY OF THE DAY. THE EXCEPTION WILL BE IN THE NW
CWA WHERE MODELS... UPSTREAM SOUNDINGS... AND SATELLITE TRENDS
SUGGEST THAT THE COVERAGE OF MID CLOUDS WILL BE A LITTLE BETTER...
LEADING TO PARTLY CLOUDY SKIES. SEVERAL CONVECTION-ALLOWING MODELS
DEPICT A FEW SPRINKLES MAKING IT INTO THE FOOTHILLS LATE THIS
AFTERNOON... BUT BASED ON THE GENERALLY DOWNSLOPE FLOW AND LACK OF
LOW LEVEL MOISTURE... BELIEVE THESE WILL HOLD JUST NW OF THE CWA.
THICKNESSES AND STATISTICAL GUIDANCE SUPPORT FORECAST HIGHS OF
86-91. -GIH
TONIGHT AND MONDAY:
THE AFOREMENTIONED COLD FRONT WILL PROGRESS SOUTHWARD INTO CENTRAL
NC TONIGHT WILL LITTLE FANFARE... OTHER THAN AN INCREASE IN CLOUD
COVER. THE FRONT IS EXPECTED TO WEAKEN AS IT MOVES THROUGH THE AREA
TONIGHT... BEFORE IT STALLS/DISSIPATES NEAR THE NC/SC BORDER ON
MONDAY. SURFACE HIGH PRESSURE WILL BUILD INTO THE AREA BEHIND THE
FRONT. HOWEVER... AS THE SURFACE HIGH CENTERED OVER THE NORTHERN
MID-ATLANTIC/NORTHEASTERN U.S. MONDAY MORNING SHIFTS EASTWARD AND
OFFSHORE ON MONDAY AFTERNOON... A LIGHT EASTERLY LOW LEVEL FLOW WILL
DEVELOP ACROSS CENTRAL NC. THIS WILL ALLOW LOW LEVEL MOISTURE TO
INCREASE... ALONG WITH POSSIBLY A FEW SHOWERS ACROSS OUR COASTAL
PLAIN COUNTIES IN THE AFTERNOON. HOWEVER... GIVEN INSTABILITY WILL
REMAIN WEAK STILL... WHILE MID LEVEL TEMPS ACTUALLY INCREASE A BIT
AS THE AFOREMENTIONED MID LEVEL RIDGES BEGINS TO BUILD EASTWARD AND
EXTENDS INTO OUR AREA... WILL ONLY KEEP A SLIGHT CHANCE OF SHOWERS
IN THE FORECAST ALONG AND TO THE EAST OF THE I-95 CORRIDOR.
LOW TEMPS MONDAY MORNING ARE EXPECTED TO BE IN THE MID TO UPPER
60S... THANKS TO THE INCREASE IN CLOUD COVER. HIGH TEMPS ON MONDAY
WILL BE TEMPERED BACK A BIT WITH THE EASTERLY LOW LEVEL FLOW. THIS
YIELDS HIGH TEMPS IN THE MID TO UPPER 80S.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 300 AM SUNDAY...
STRONG UPPER ANTI-CYCLONE OVER THE CENTRAL U.S. MIGRATES EWD AND
SETTLES OVER THE SOUTHERN APPALACHIANS MONDAY NIGHT THROUGH
WEDNESDAY. THE RISING HEIGHTS AND ASSOCIATED WARMING ALOFT WILL ACT
TO SUPPRESS THE ABILITY FOR CONVECTION TO FORM TUESDAY...AND JUST A
SLIGHT CHANCE OF AFTERNOON CONVECTION OVER THE NW PIEDMONT/TRIAD
REGION WEDNESDAY AFTERNOON. THE PRESENCE OF THE RIDGE AXIS ALOFT AND
THE SFC HIGH ANCHORED OFFSHORE WILL CAUSE VERY WARM/HOT CONDITIONS
TUESDAY AND WEDNESDAY. AFTERNOON THICKNESS PROJECTED TO REACH INTO
THE 1420-1425M RANGE...10-15M ABOVE NORMAL. THIS SUGGEST MAX TEMPS
TUESDAY IN THE MID-UPR 80S TUESDAY AND UPR 80S-AROUND 90 WEDNESDAY.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
THURSDAY...A FAIRLY STOUT S/W IN THE NORTHERN STREAM WILL CROSS THE
GREAT LAKES THU. THIS FEATURE WILL ACT TO WEAKEN THE UPPER LEVEL
RIDGE OVER THE CAROLINAS AND CAUSE THE ANTI-CYCLONE TO RETROGRADE
BACK TOWARD THE MS RIVER VALLEY. THE FALLING HEIGHTS WILL AID TO
SHARPEN THE PIEDMONT SFC TROUGH BY THU AFTERNOON. THIS MAY SUPPORT
THE DEVELOPMENT OF ISOLATED-SCATTERED CONVECTION OVER THE NW
PIEDMONT THOUGH MOISTURE AVAILABILITY STILL IN QUESTION. IT WILL
REMAIN VERY WARM THANKS TO THE SW LOW LEVEL FLOW. THICKNESSES
THURSDAY AFTERNOON REMAIN IN THE 1420S. MAX TEMPS IN THE UPPER
80S-AROUND 90 WILL ONCE AGAIN BE THE NORM.
THURSDAY NIGHT THROUGH FRIDAY...THE NORTHERN STREAM S/W WILL
CONTINUE MOVING E-SE AND RESULT IN LOWERING UPR LEVEL HEIGHTS ACROSS
THE CAROLINAS THU NIGHT INTO FRIDAY. THE ATTENDANT SFC FRONT WILL BE
ENTERING OUR FORECAST AREA BY FRIDAY MORNING THEN SLIDE SEWD AS THE
S/W CROSSES NEW ENGLAND AND EXISTS OFFSHORE. SINCE BEST UPPER LEVEL
SUPPORT WELL TO OUR NORTH AND MOISTURE TRANSPORT MARGINAL DUE TO
WESTERLY FLOW AHEAD OF THE SYSTEM...CHANCES FOR SHOWERS AND ISOLATED
T-STORM APPEAR TO BE NO HIGHER THAN 30-40 PERCENT THU NIGHT INTO
FRIDAY WITH THE BETTER CHANCES FOR SHOWERS/T-STORMS LIKELY CONFINED
TO THE SOUTHERN AND EASTERN COUNTIES BY FRIDAY AFTERNOON. GFS STILL
APPEARS A LITTLE TOO FAST IN MOVING THE SYSTEM THROUGH CONSIDERING
THE BEST PUSH/EWD ACCELERATION WILL BE ACROSS NEW ENGLAND AND THE
NORTHERN MID ATLANTIC. EXPECTED SHOWER COVERAGE AND ASSOCIATED CLOUD
COVER WILL RESULT IN SLIGHTLY COOLER TEMPS THOUGH DEWPOINTS WELL
INTO THE 60S TO NEAR 70 WILL STILL MAKE IT FEEL VERY WARM. MAX TEMPS
IN THE LOW-MID 80S.
FRIDAY NIGHT INTO SATURDAY...LONG TERM MODEL GUIDANCE STILL
SUGGESTING THE ADVECTION OF COOLER AND DRIER AIR INTO CENTRAL NC
FOR THE START OF THE WEEKEND. MODEL THICKNESSES DROP INTO THE 1360S
BY SATURDAY MORNING WITH 1350S POSSIBLE BY NEXT SUNDAY MORNING.
CONSIDERING THE ORIGINS OF THE CANADIAN HIGH BUILDING INTO OUR
REGION...THIS SEEMS PLAUSIBLE. MAX TEMPS SATURDAY MAY REMAIN BELOW
80 DEGREES MOST SPOTS.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 640 AM SUNDAY...
24 HOUR TAF PERIOD:
VFR CONDITIONS ARE GENERALLY EXPECTED TO PREVAIL ACROSS THE AREA AS
DRY COLD FRONT APPROACHES THE REGION FROM THE NORTH TODAY. THE COLD
FRONT IS EXPECTED TO SLOWLY CROSS CENTRAL NC TONIGHT. IF ANY MVFR
FOG DEVELOPS THIS MORNING AT KRWI IT WILL MIX OUT QUICKLY WITH
DIURNAL MIXING AND SHOULD BE GONE BY 12Z AT THE LATEST. OTHERWISE...
WE WILL SEE MID AND HIGH LEVEL CLOUD COVER ON THE INCREASE THIS
MORNING AS A WEAK DISTURBANCE ALOFT MOVES ACROSS THE AREA. THE
AFOREMENTIONED SURFACE FRONT IS NOT EXPECTED TO MOVE INTO THE AREA
UNTIL LATE TONIGHT. HOWEVER... OUTSIDE OF AN INCREASE IN VFR
CLOUDS... THE FRONT WILL COME THROUGH WITH LITTLE FANFARE AND STALL
NEAR THE NC/SC BORDER AROUND 12Z MONDAY.
OUTLOOK:
PRE-DAWN/MORNING SUB-VFR CONDITIONS WILL BE POSSIBLE EACH MORNING...
ALTHOUGH CONFIDENCE IS VERY LOW FOR ANY WIDESPREAD SUB-VFR
CONDITIONS. OTHERWISE... VFR CONDITIONS ARE EXPECTED... WITH
GENERALLY DRY CONDITIONS (VERY SMALL CHANCE OF A AFTERNOON/EVENING
SHOWER OR STORM EACH DAY AS WELL... BEST CHANCE ON WEDNESDAY AND
THURSDAY AT KGSO/KINT).
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD/HARTFIELD
NEAR TERM...HARTFIELD/BSD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...BSD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
931 PM CDT MON SEP 9 2013
.UPDATE...
ISSUED AT 931 PM CDT MON SEP 9 2013
BUMPED UP POPS INTO THE 50-60 PERCENT RANGE IN THE DEVILS LAKE
BASIN FOR THE REST OF THE EVENING AS THE LINE OF STORMS OVER NORTH
CENTRAL ND HAS HELD TOGETHER. NAM AND HRRR HAVE THE STORMS
CONTINUING THROUGH THE DEVILS LAKE BASIN BEFORE DIMINISHING AS
THEY MOVE FURTHER EAST. THINK THAT THERE WILL BE SOME WEAKENING
AND DISSIPATING AS THE LINE MOVES FURTHER EAST INTO STABLE AIR
OVER THE NORTHERN RED RIVER VALLEY SO KEPT POPS AROUND 30-40
ACROSS THE REST OF THE NORTHERN FORECAST AREA.
A FEW SPOTS HAVE LOWERED IN VISIBILITY THIS EVENING...BUT NO DENSE
FOG YET. WILL CONTINUE JUST TO KEEP A PATCHY MENTION FOR NOW AS
WITH WINDS SHIFTING WEST BEHIND THE WEAK SFC TROUGH THERE SHOULD
BE SOME MIXING AND SLIGHTLY DRIER AIR MOVING IN.
UPDATE ISSUED AT 629 PM CDT MON SEP 9 2013
RADAR TRENDS SHOW US FAIRLY QUIET FOR THE TIME BEING EXCEPT FOR
SOME LIGHT SHOWERS OR DRIZZLE IN SOME SPOTS. CONVECTION OUT IN
NORTHWESTERN ND IS ON TRACK TO MOVE INTO THE NORTHWESTERN COUNTIES
LATER ON THIS EVENING. HOWEVER...THE NAM AND HRRR SHOW THE
ACTIVITY DISSIPATING BEFORE GETTING VERY FAR INTO OUR AREA. A FEW
OF THE OTHER SOLUTIONS KEEP SOME PRECIP MOVING IN...BUT GIVEN THE
LACK OF EVEN ELEVATED INSTABILITY AM NOT OPTIMISTIC. CONTINUED TO
KEEP 30-40 POPS GOING IN THE NORTH FOR ANYTHING HOLDING TOGETHER
AS THE SHORTWAVE MOVES EAST THIS EVENING BUT WILL HOLD OFF ON ANY
RAISING OR LOWERING OF POPS AT THIS POINT.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 300 PM CDT MON SEP 9 2013
THE GFS IS DOING THE BEST JOB INITIALIZING THE CURRENT DEFORMATION
RAIN BAND...SO WILL UTILIZE THIS SOLUTION WITH NO MODEL DOING VERY
WELL OF LATE.
FOR TONIGHT...EXPECT SHOWERS AND A FEW STORMS MAINLY IN THE
NORTHERN 1/3 OF THE AREA. A FEW STORMS COULD EVEN BE STRONG TO
PERHAPS LOCALLY SEVERE IN THE DVL BASIN...WITH LARGE HAIL
POSSIBLE/STRONG IF SOME INSOLATION DEVELOPS LATE THIS AFTERNOON.
THERE IS ALSO SOME LINGERING INSTABILITY IN THE SOUTH AND EAST
THROUGH THIS EVENING AHEAD OF THE SFC BOUNDARY...SO A FEW STRONG
STORMS ALSO POSSIBLE THERE. SINCE THIS AREA HAS BEEN UNDER CLOUDS
ALL DAY...NOT ANTICIPATING TOO MUCH WIDESPREAD ACTIVITY HERE EITHER.
THERE SHOULD ALSO BE PATCHY FOG IN ALL AREAS TONIGHT...GIVEN VERY
HIGH LOW LEVEL MOISTURE. IF AREAS CLEAR OUT MORE LATER
TONIGHT...THEN FOG COULD BECOME LOCALLY DENSE BUT EXPECTING CLOUDS
TO REMAIN IN MOST AREAS TONIGHT.
ON TUE...THE UPPER WAVE WILL MOVE SLOWLY EAST AND THERE COULD BE A
FEW SHOWERS/STORMS MAINLY IN THE NORTH. TEMPS WILL BE A BIT WARMER
THAN TODAY WITH MORE SUNSHINE.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON SEP 9 2013
FOR WED/THU...EXPECT DRY AND COOL WEATHER WITH HIGH PRESSURE
BUILDING INTO THE REGION. THERE WILL ALSO BE PLENTIFUL SUNSHINE
WITH DEEP LAYERED SUBSIDENCE AND A DRY AIRMASS IN PLACE...SO IT
WILL BE COOL OVERNIGHT.
THURSDAY NIGHT THROUGH MONDAY...12 UTC GFS/ECMWF IN GOOD AGREEMENT
THROUGH 00 UTC SATURDAY...DIVERGING THEREAFTER WITH INTERACTION
BETWEEN A HUDSON BAY TROUGH AND A STAGNANT GREAT BASIN CLOSED LOW.
GENERAL SYNOPTIC IDEA SHOWS A CANADIAN TROUGH MOVING INTO HUDSON
BAY BY 00 UTC SUNDAY AND IN THE PROCESS ENVELOPES A CLOSED LOW
ACROSS THE CENTRAL ROCKIES. WITH THIS PATTERN...TWO POTENTIAL AREAS
OF PRECIPITATION COULD DEVELOP ACROSS THE FORECAST AREA ON SATURDAY.
THE FIRST IS ASSOCIATED WITH THE CANADIAN COLD FRONT DROPPING SOUTH
AND THE SECOND IS FROM WARM AIR ADVECTION ASSOCIATED WITH THE CLOSED
LOW TO THE SOUTH. THE ECMWF IS MOST BULLISH WITH PRECIPITATION FROM
THE SOUTH...WHEREAS THE GFS/DGEX/GEM ARE FARTHER SOUTH AND DRIER
ACROSS THE FORECAST AREA. WILL COVER THIS IN THE GRIDS WITH CHANCE
POPS SPREADING FROM WEST TO EAST FRIDAY NIGHT THROUGH SATURDAY
NIGHT. REST OF THE PERIOD SHOULD BE DRY WITH SURFACE HIGH PRESSURE
ACROSS THE REGION. TEMPERATURES WILL BE MUCH CLOSER TO SEASONAL
NORMALS WITH HIGHS FROM THE MID 60S TO LOWER 70S AND LOWS FROM THE
MID 40S TO MID 50S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 629 PM CDT MON SEP 9 2013
CIGS HAVE CONTINUED TO BOUNCE BETWEEN MVFR DOWN TO IFR AT TIMES
AND THIS WILL CONTINUE THROUGH THE EVENING. NORTHWEST WINDS WILL
BRIEFLY BECOME LIGHT AND VARIABLE THIS EVENING AS A WEAK TROUGH OF
LOW PRESSURE MOVES THROUGH. SOME SHOWERS WILL MOVE INTO THE KDVL
AREA AHEAD OF A SFC BOUNDARY CURRENTLY OVER NORTHWESTERN ND. LIGHT
WINDS AND A LOT OF MOISTURE WILL PRODUCE SOME PATCHY FOG FORMATION
TONIGHT AHEAD OF THIS BOUNDARY...BUT WHICH SITES WILL GO DOWN IS
STILL VERY UNCERTAIN. FOR NOW WILL GO WITH 3-5SM VIS AND MAKE
ADJUSTMENTS AS NEEDED IF ANY VIS GO DOWN EVEN FURTHER. THE
BOUNDARY MOVING THROUGH WILL SHIFT WINDS BACK TO THE NORTHWEST AND
SHOULD SCOUR OUT FOG...BUT SOME MVFR CIGS WILL STILL BE POSSIBLE
IN THE COOL AIR BEHIND THE BOUNDARY. CONDITIONS WILL RETURN TO VFR
BY LATE MORNING TO EARLY AFTERNOON TOMORROW.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...DK
LONG TERM...DK/ROGERS
AVIATION...JR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
116 PM CDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 116 PM CDT SUN SEP 8 2013
MAIN FORECAST UPDATE WAS TO ADJUST POPS THIS AFTERNOON. AN UPPER
IMPULSE MOVING FROM NORTHEAST MONTANA INTO SASKATCHEWAN IS
PRODUCING SCATTERED SHOWERS AND THUNDERSTORMS OVER NORTHWEST TO
NORTH CENTRAL NORTH DAKOTA INTO EAST CENTRAL MONTANA. THE AREA OF
SHOWERS OVER THE SOUTH CENTRAL HAS MOVED INTO THE JAMES RIVER
BASIN AND DISSIPATED. THUS LOWERED POPS TO CHANCE CATEGORY EXCEPT
FOR THE NORTHWEST-NORTH CENTRAL. THE 12Z WRF...15Z HRRR MESOSCALE
MODELS AS WELL AS THE NAM/GFS INDICATE BEST CHANCES OF CONVECTION
WILL HOLD OFF UNTIL TONIGHT...BUT DID BRING SOME INCREASING
CHANCES INTO THE SOUTHWEST LATER THIS AFTERNOON. ALSO LOWERED
CLOUD COVER ACROSS THE SOUTHWEST AND SOUTH CENTRAL EARLY THIS
AFTERNOON.
UPDATE ISSUED AT 1013 AM CDT SUN SEP 8 2013
QUITE A FEW CHANGES TO THE MORNING UPDATE...MAINLY CENTERED AROUND
CURRENT SHOWER ACTIVITY AND ANTICIPATED DEVELOPMENT OVER THE NEXT
FEW HOURS. CURRENTLY...SHOWERS OVER SOUTH CENTRAL NORTH DAKOTA
CONTINUE TO TRANSLATE EAST. OF THE SHORT TERM MODELS...THE 12 UTC
HRRR SEEMED TO HAVE THE BEST HANDLE ON THE CURRENT SHOWERS. THUS
UTILIZED THE HRRR FOR POP/QPF FORECAST THROUGH THE EARLY
AFTERNOON. THIS RESULTED IN LOWERING OF POPS ACROSS THE NORTH
WHERE LITTLE IS GOING ON...AND INCREASING POPS OVER THE SOUTH
CENTRAL. ALSO LOWERED QPF AMOUNTS THROUGH MUCH OF THE DAY AS RAIN
AMOUNTS HAVE BEEN LIGHT IN THIS AREA OF HIGH BASED SHOWERS. DO NOT
EXPECT HIGHER QPF AMOUNTS UNTIL WE GET SOME CONVECTIVE ELEMENTS
INVOLVED. WITH THE EXTENSIVE CLOUD COVER...ALSO LOWERED
TEMPERATURES A FEW DEGREES MOST AREAS. THINK THE BETTER
PRECIPITATION CHANCES WILL ARRIVE TONIGHT BUT DID BEGIN TO
INCREASE POPS ACROSS THE WEST LATER THIS AFTERNOON.
UPDATE ISSUED AT 638 AM CDT SUN SEP 8 2013
COPIOUS AMOUNTS OF MOISTURE CONTINUE TO OVERSPREAD WESTERN AND
CENTRAL NORTH DAKOTA THIS MORNING AHEAD OF AN APPROACHING
SHORTWAVE. THE LATEST RAP PROGS PWATS GREATER THAN 1.5 INCHES OVER
AREAS SOUTH OF I-94 THIS MORNING. THIS IS ABOUT 200 PERCENT OF
NORMAL FOR SEPTEMBER. GIVEN THE SATURATED ENVIRONMENT...THINK
THE CURRENT FLASH FLOOD WATCH LOOKS GOOD FOR TODAY AND TONIGHT.
NO MAJOR UPDATES WERE REQUIRED FOR THIS UPDATE. ONLY MODIFIED THE
HOURLY TEMP/DEWPOINT/WIND GRIDS BASED ON CURRENT OBS/TRENDS. THE
UPDATED PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT SUN SEP 8 2013
FORECAST CHALLENGES/HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE
THE COVERAGE AND AMOUNT OF PRECIPITATION NOW THROUGH TONIGHT
ALONG WITH ANOTHER ROUND OF SEVERE WEATHER.
CURRENTLY...UPPER LEVEL RIDGE AXIS CENTERED ACROSS THE DAKOTAS
THIS MORNING. CONVECTION CONTINUES TO BE VIGOROUS FROM ACROSS
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA...INTO SOUTH DAKOTA AND
WEST ACROSS SOUTHEAST MONTANA ALONG AN INSTABILITY AXIS AND IN THE
VICINITY OF A LOW LEVEL JET. AT THIS TIME STORMS ARE NON-
SEVERE...DUE IN PART TO RELATIVELY WEAK MID LEVEL LAPSE RATES.
ADDITIONAL SHOWERS/T-STORMS DEVELOPING OVER NORTHEAST MONTANA AND
EAST OVER NORTH CENTRAL AND NORTHEASTERN NORTH DAKOTA.
EXPECT THE CONVECTION OVER MONTANA TO SHIFT NORTH AND EAST INTO
WESTERN AND PORTIONS OF CENTRAL NORTH DAKOTA THIS MORNING AS A
POTENT LEAD S/WV IMPULSE NOW LIFTING ACROSS WYOMING MOVES INTO
EASTERN MONTANA 12-18Z...AND AS THE LLJ BECOMES MORE FOCUSED OVER
WESTERN ND BY 12Z AND SHIFTS EAST INTO CENTRAL ND LATER THIS
MORNING.
SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS MUCH OF THE REGION
TODAY INTO TONIGHT AS ADDITIONAL MID LEVEL WAVES LIFT NORTHEAST
ACROSS THE NORTHERN PLAINS...IN ADVANCE OF THE UPPER LOW (NOW
OVER NORTHERN IDAHO) AS IT TRACKS EAST ACROSS NORTHERN MONTANA. AT
THIS TIME EXPECT THE HEAVIER PRECIPITATION FROM THE AFTERNOON INTO
THE EVENING HOURS ACROSS NORTH DAKOTA WHEN DIFFLUENT FLOW ALOFT
LINKS TO STRONG THERMAL LIFT NORTH OF AN AREA OF LOW PRESSURE
ADVANCING NORTH AND EAST ACROSS SOUTH DAKOTA. THE STRONG SYNOPTIC
FORCING WILL COINCIDE WITH PLENTY OF INSTABILITY AND SHEAR TO
TRIGGER AT LEAST A FEW SEVERE STORMS THROUGH THE PERIOD.
IN ADDITION TO THE FORCING AND SEVERE PARAMETERS...MOISTURE
CONTINUES TO BE PUMPED FROM THE GULF OF MEXICO AROUND THE
SUBTROPICAL RIDGE INTO THE NORTHERN PLAINS. SURFACE TO 300MB
PRECIPITABLE WATER VALUES ARE CURRENTLY OVER 200 PERCENT OF NORMAL
FOR THIS TIME OF YEAR...AND ARE EXPECTED TO INCREASE TO NEAR 2
INCHES TODAY EXCEEDING THE MAXIMUM OBSERVED. THUS ANY STORMS WILL
HAVE THE POTENTIAL TO BE HEAVY RAINERS...SO WE HAVE EXTENDED THE
FLASH FLOOD WATCH THROUGH THIS SUNDAY NIGHT...AND EXPANDED THE
AERIAL COVERAGE TO INCLUDE ALL OF WEST AND CENTRAL NORTH DAKOTA.
ESPECIALLY PRONE TO FLASH FLOODING WILL BE PORTIONS OF WESTERN AND
SOUTHERN NORTH DAKOTA WHICH ALREADY SAW RAINFALL AMOUNTS UP TO
THREE INCHES THE PAST 12-24 HOURS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 415 AM CDT SUN SEP 8 2013
THE MEDIUM RANGE MODELS ARE RELATIVELY SLOWER WITH THE PROGRESSION
OF AN UPPER LEVEL LOW ACROSS NORTH DAKOTA MONDAY. THE LATEST
GUIDANCE NOW PIVOTS THE UPPER TROUGH AXIS ACROSS NORTH DAKOTA
MONDAY NIGHT (INSTEAD OF MONDAY AS GUIDANCE 24 HOURS AGO PROGGED).
AS A RESULT...KEPT CHANCE POPS IN FOR MONDAY...THEN FORECAST A
DECREASING POP TREND FROM SOUTHWEST TO NORTHEAST AS SUBSIDENCE
FILTERS IN BEHIND THE TROUGH AXIS MONDAY NIGHT. LINGERING SLIGHT
CHANCE POPS ARE FORECAST FOR BOTTINEAU...ROLETTE...AND PIERCE
COUNTIES TUESDAY MORNING. HOWEVER...LITTLE IMPACT IS EXPECTED.
DRY CONDITIONS ARE THEN EXPECTED AREAWIDE TUESDAY AFTERNOON THROUGH
FRIDAY AS UPPER LEVEL RIDGING BUILDS OVER THE NORTHERN ROCKIES AND
INTO THE NORTHERN PLAINS. ABOVE NORMAL TEMPERATURES ARE EXPECTED TO
CONTINUE THROUGH THE REMAINDER OF THE WORK WEEK.
ANOTHER ROUND OF PRECIPITATION IS FORECAST FOR SATURDAY AS AN UPPER
LEVEL SHORTWAVE EMANATING FROM THE ROCKIES IS PROGGED TO LIFT INTO
WESTERN NORTH DAKOTA. NOT REAL CONFIDENT WITH THE TIMING OF THIS
FEATURE AS THE MEDIUM RANGE MODELS HAVE RECENTLY BEEN STRUGGLING
WITH SHORTWAVE TIMING ISSUES. WILL CONTINUE TO MONITOR AND MAKE
ADJUSTMENTS AS NEEDED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 116 PM CDT SUN SEP 8 2013
MVFR CEILING REMAINS AT KISN TO START THE PERIOD. OTHERWISE VFR
CONDITIONS ELSEWHERE. CEILINGS AT KISN SHOULD LIFT TO VFR BY THE
AROUND 21 UTC. EXPECT SHOWER AND THUNDERSTORM CHANCES WILL
INCREASE FROM WEST TO EAST LATE THIS AFTERNOON AND TONIGHT. THEN
KEPT A PERIOD OF MVFR-IFR CEILINGS LATE TONIGHT THROUGH MID
MORNING MONDAY...BEFORE IMPROVING TOWARD THE END OF THE FORECAST
PERIOD.
&&
.HYDROLOGY...
ISSUED AT 415 AM CDT SUN SEP 8 2013
AS MENTIONED ABOVE IN THE SHORT TERM SECTION...HAVE EXPANDED AND
EXTENDED THE FLASH FLOOD WATCH TO INCLUDE ALL OF WESTERN AND
CENTRAL NORTH DAKOTA THROUGH TONIGHT. VERY HIGH ATMOSPHERIC
MOISTURE WILL LINE UP WITH FAVORABLE INSTABILITY AND SYNOPTIC
FORCING TO WARRANT THIS CHANGE. MODELS ARE PROJECTING PWAT VALUES
EXCEEDING THE MAXIMUM OBSERVED FOR THIS TIME OF THE SEASON...NEAR 2
INCHES ACROSS MUCH OF THE REGION.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH MONDAY MORNING FOR NDZ001>005-009>013-
017>023-025-031>037-040>048-050-051.
&&
$$
UPDATE...TWH
SHORT TERM...NH
LONG TERM...TM
AVIATION...TWH
HYDROLOGY...NH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
104 PM CDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 104 PM CDT SUN SEP 8 2013
AREA OF SHOWERS ACROSS SOUTHERN ND/NORTHERN SD HAS DISSIPATED...
BUT CONVECTION HAS BEEN PERSISTENT ACROSS PORTIONS OF WEST CENTRAL
MN WITH DISSIPATING MCV. UPDATED POPS TO INCLUDE 60S IN THE FAR
SOUTHEASTERN FORECAST AREA AT 18 UTC...BUT THESE SHOWERS AND EMBEDDED
THUNDERSTORMS WILL MOVE QUICKLY INTO EAST-CENTRAL MN FOR THE REST
OF THE AFTERNOON. CLOUD COVER AND RAIN ACROSS THE SOUTHEAST HAS
RESULTED IN VERY COOL TEMPERATURES WITH LITTLE REBOUND. CURRENT
TEMPERATURES ARE STILL IN THE MID TO UPPER 50S...SO DROPPED
AFTERNOON HIGHS SEVERAL DEGREES IN THESE AREAS. REST OF THE
FORECAST THROUGH 00 UTC IN GOOD SHAPE WITH ONLY SCATTERED SHOWERS
POSSIBLE.
UPDATE ISSUED AT 1004 AM CDT SUN SEP 8 2013
FORECAST CONFIDENCE IS LOW AS MODELS HAVE PERFORMED POORLY WITH
ONGOING PRECIPITATION THIS MORNING. WILL FOLLOW THE HRRR FOR THE
MORNING UPDATE...WHICH BEST REFLECTS REALITY.
AREA OF MODERATE SHOWERS WITH ISOLATED EMBEDDED THUNDER STRETCHES
FROM NORTH OF ST. CLOUD TO JUST SOUTH OF GRAND FORKS AND IS IN AN
AREA OF ENHANCED 300 HPA DIVERGENCE AND 850 HPA FRONTOGENESIS.
HRRR SUGGESTS THIS CONVECTION WILL CONTINUE EASTWARD AND DISSIPATE
BY EARLY AFTERNOON. UPDATED POPS TO REFLECT THIS THINKING. ANOTHER
AREA OF SHOWERS STRETCHES FROM SOUTHWEST OF BISMARCK TO EAST OF
ABERDEEN. HRRR SHOWS THIS PRECIPITATION ALSO WEAKENING AS IT MOVES
EAST. HOWEVER...AM NOTICING SOME REDEVELOPMENT ACROSS THE SOUTHERN
VALLEY AS A REMNANT MCV EVIDENT IN RADAR REFLECTIVITY MOVES INTO
THE ND/SD/MN BORDER REGION. WILL NEED TO WATCH THIS FOR THE NEXT
UPDATE...BUT DO NOT ANTICIPATE ANY STRONGER STORMS WITH INSTABILITY
MAXIMIZED FARTHER SOUTH ACROSS WESTERN SD.
OVERALL...ONCE BAND OF SHOWERS/STORMS MOVES OUT OF WEST CENTRAL
MN...THINK THUNDERSTORM COVERAGE WILL BE SCATTERED FOR THE REST
OF THE MORNING AND AFTERNOON AS THE PRIMARY FORCING REMAINS WEST
OF THE FORECAST AREA. ATTENTION TONIGHT WILL TURN TO FLOODING AND
SEVERE POTENTIAL. UPDATED POPS AND WX THOUGH 00 UTC AND ALSO
DECREASED TEMPERATURES A FEW DEGREES WITH PERSISTENT CLOUD COVER.
AFTERNOON HIGHS WILL REACH THE UPPER 60S ALONG THE INTERNATIONAL
BORDER TO THE UPPER 70S ALONG THE SD STATE LINE.
UPDATE ISSUED AT 659 AM CDT SUN SEP 8 2013
VERY COMPLEX PRECIP PATTERN THIS MORNING. NO MODEL HANDLING IT
WELL SO GOING OFF CURRENT RADAR AND ADJUSTING FOR A FEW HOURS
AHEAD FOR IMMEDIATE UPDATES. MAIN MCS DWINDLED IN SE ND/NE SD AS
EXPECTED...BUT OUT AHEAD OF IT SOME CONVECTION FORMED IN THE FARGO
AREA PRODUCING UP TO 1 INCH OF RAIN QUICKLY. THIS CLUSTER MOVING
EAST INTO DTL-FFM AREAS. DID UP POPS REST OF THIS MORNING INTO
WCNTRL MN FOR THIS. OTHERWISE MORE SCATTERED LIGHT ACTIVITY
NORTHWARD INTO THE NRN VALLEY. WOULD APPEAR THIS AFTN TO SEE
SCATTERED ACTIVITY BUT MOST OF THE FOCUS WILL WAIT TIL OVERNIGHT.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 324 AM CDT SUN SEP 8 2013
THREAT FOR HEAVY RAIN TONIGHT IS THERE...BUT WHERE AND HOW MUCH IS
THE MAIN QUESTION. MODEL QPF HAS BEEN RATHER POOR LATELY SO
CONFIDENCE IN AMOUNTS AND EXACT PLACEMENT POOR.
CURRENTLY...HAVE REMAINS OF TSTM COMPLEX THAT WAS IN SW/SCNTRL
ND/NRN SD MOVING EAST SLOWLY AND WEAKENING AS IT ENTERS THE
ABERDEEN-OAKES AREA. BUT HRRR DOES TAKE SOME SHOWERS EAST ACROSS
THE SD/ND BORDER REGION INTO WCNTRL THIS MORNING SO INCLUDED POPS
FOR THIS. HOWEVER IT IS RUNNING INTO QUITE A BIT OF DRY AIR SOON
AND SHOULD START TO REALLY WEAKEN.
MODELS 12Z SAT AND 00Z SUN INDICATED TSTM COMPLEX IN WCNTRL OR NW
ND AT THIS TIME AND INSTEAD DEVELOPMENT HAS BEEN FARTHER SOUTH IN
A NARROW 850 MB LOW LEVEL JET ZONE IN THE DICKINSON-HETTINGER-
BOWMAN AREA OF ND INTO NW SD. THUS PREV FCST IDEA OF LIKELY POPS
SPREADING INTO DVL BASIN THIS MORNING SEEMS A BIT OFF AND REDUCED
POPS TO HIGH CHANCE. RADAR HAS BEEN SHOWING SOME VERY LIGHT
SHOWERS FROM THE MID LEVEL CLOUD COVER MOVING INTO DVL BASIN BUT
WIDESPREAD RAINFALL NOT ANTICIPATED AS FOCUS WILL CONTINUE TO BE
MORE IN SW ND AND THEN INTO CNTRL ND TODAY WITH LOW LEVEL 850 MB
JET AND MOISTURE.
TONIGHT IS THE MAIN ACTION AS SHORT WAVE LIFTS NORTHEAST FROM
MONTANA TROUGH INTO WRN ND AND SFC LOW IS STILL FCST TO TRACK FROM
WRN SD INTO FAR NE SD/SE ND BY 12Z MON. ALL INDICATIONS STILL
FAVOR A LARGE TSTM COMPLEX NORTHWEST OF SFC LOW FROM SW-CNTRL INTO
NE ND/FAR NW MN/SRN MANITOBA OVERNIGHT INTO MONDAY MORNING. KEPT
IDEA OF HVY RAIN MENTIONED IN GRIDDS AND CATEGORICAL POPS MAINLY
NORTH OF A VALLEY CITY-FARGO-BEMIDJI AREAS. GFS IS QUITE STRONG
WITH LOW LEVEL JET (40 KTS) AND HAS MAX 850 INSTABILITY GRADIENT IN
SE-ECNTRL ND-WCNTRL MN 09Z-12Z MON PERIOD AND THUS IDEA OF
ELEVATED SVR VERY POSSIBLE ALONG SRN EDGE OF ANY MCS. FOR RAINFALL
PWATS OF 2 INCHES AT 12Z MON WOULD ARGUE FOR WIDESPREAD 1-2 INCH
RAIN POTENTIAL IN MCS AREA WITH LOCALLY HEAVIER AMOUNTS.
CONSIDERING PAST 60-90 DAYS HAVE BEEN VERY DRY IN OUR REGION RAIN
WILL SOAK INTO THE GROUND WITH RUNOFF MORE LIMITED TO CITY-URBAN
AREAS. AND WITH STILL UNCERTAINTY DUE TO POOR MODEL QPF
PERFORMANCES OF LATE AND THE FACT THAT MAIN RAIN IS TONIGHT HELD
OFF ON ANY FLASH FLOOD WATCHES. BUT SOME MAY BE NEEDED ONCE HVY
RAIN AREA CAN BE PEGGED BETTER.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 324 AM CDT SUN SEP 8 2013
500 MB UPPER TROUGH TO MOVE OVER MANITOBA/NE ND/NW MN MON NIGHT-
TUES AND THUS WILL LEAVE IN LOW POPS FOR THIS.
WEDNESDAY-SATURDAY...BROAD CANADIAN SFC HIGH PRESSURE WILL DROP FROM
CENTRAL CANADA INTO THE GREAT LAKES MID TO LATE WEEK WITH NORTHWEST
FLOW ALOFT...KEEPING THE AREA DRY. MORE SEASONABLE HIGH TEMPS IN
THE 60S TO LOW 70S ARE EXPECTED BY THURSDAY/FRIDAY. THE COOLEST
NIGHT DURING THE PERIOD LOOKS TO BE THURSDAY NIGHT...AS THE SFC HIGH
APPROACHES. TEMPS SHOULD EASILY FALL INTO THE 40S...BUT IT IS
POSSIBLE THAT THESE TEMPS MAY BE TOO WARM...DEPENDING ON THE
EVENTUAL POSITION OF THE SFC HIGH.
BY EARLY NEXT WEEKEND MORE DISAGREEMENT EXISTS AMONG MODELS WITH THE
PATTERN EVOLUTION. HOWEVER...BOTH THE GFS/ECMWF DO BRING A SHORTWAVE
TROUGH INTO THE PLAINS ON SATURDAY...PERHAPS PROVIDING THE NEXT
OPPORTUNITY FOR SOME PRECIPITATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 104 PM CDT SUN SEP 8 2013
THE MAIN CHALLENGE THROUGH THIS FORECAST WILL BE CIGS AND
CONVECTION. THERE WILL BE A BAND OF IFR/MFVR CIGS IN THE NORTH THAT
MAY PERSIST INTO AT LEAST THIS EVENING. FURTHER SOUTH...EXPECT MORE
VFR CONDITIONS UNTIL STEADY SHOWERS AND STORMS ARRIVE LATER TONIGHT
INTO MONDAY MORNING. RAIN COULD GET HEAVY IN THE NORTH MONDAY
MORNING ALONG WITH WIDESPREAD MVFR TO PERHAPS IFR CONDITIONS NEAR
VERY HEAVY RAIN. FOR NOW HAVE KEPT IT MODERATE SHOWERS FOR
GFK/TVF...BUT THIS AREA COULD BE TARGETED FOR +SHRA/+TSRA FOR THE
12Z MON-18Z MON TIMEFRAME AND WILL MONITOR. IN ADDITION...THERE
COULD BE STRONGER WINDS NEAR THUNDERSTORMS LATE TONIGHT AND MONDAY
MORNING AFFECTING MAINLY SOUTHERN AREAS...BUT WON/T MENTION FOR NOW
BUT CONTINUE TO MONITOR.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...RIDDLE
LONG TERM...MAKOWSKI/RIDDLE
AVIATION...DK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1014 AM CDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 1013 AM CDT SUN SEP 8 2013
QUITE A FEW CHANGES TO THE MORNING UPDATE...MAINLY CENTERED AROUND
CURRENT SHOWER ACTIVITY AND ANTICIPATED DEVELOPMENT OVER THE NEXT
FEW HOURS. CURRENTLY...SHOWERS OVER SOUTH CENTRAL NORTH DAKOTA
CONTINUE TO TRANSLATE EAST. OF THE SHORT TERM MODELS...THE 12 UTC
HRRR SEEMED TO HAVE THE BEST HANDLE ON THE CURRENT SHOWERS. THUS
UTILIZED THE HRRR FOR POP/QPF FORECAST THROUGH THE EARLY
AFTERNOON. THIS RESULTED IN LOWERING OF POPS ACROSS THE NORTH
WHERE LITTLE IS GOING ON...AND INCREASING POPS OVER THE SOUTH
CENTRAL. ALSO LOWERED QPF AMOUNTS THROUGH MUCH OF THE DAY AS RAIN
AMOUNTS HAVE BEEN LIGHT IN THIS AREA OF HIGH BASED SHOWERS. DO NOT
EXPECT HIGHER QPF AMOUNTS UNTIL WE GET SOME CONVECTIVE ELEMENTS
INVOLVED. WITH THE EXTENSIVE CLOUD COVER...ALSO LOWERED
TEMPERATURES A FEW DEGREES MOST AREAS. THINK THE BETTER
PRECIPITATION CHANCES WILL ARRIVE TONIGHT BUT DID BEGIN TO
INCREASE POPS ACROSS THE WEST LATER THIS AFTERNOON.
UPDATE ISSUED AT 638 AM CDT SUN SEP 8 2013
COPIOUS AMOUNTS OF MOISTURE CONTINUE TO OVERSPREAD WESTERN AND
CENTRAL NORTH DAKOTA THIS MORNING AHEAD OF AN APPROACHING
SHORTWAVE. THE LATEST RAP PROGS PWATS GREATER THAN 1.5 INCHES OVER
AREAS SOUTH OF I-94 THIS MORNING. THIS IS ABOUT 200 PERCENT OF
NORMAL FOR SEPTEMBER. GIVEN THE SATURATED ENVIRONMENT...THINK
THE CURRENT FLASH FLOOD WATCH LOOKS GOOD FOR TODAY AND TONIGHT.
NO MAJOR UPDATES WERE REQUIRED FOR THIS UPDATE. ONLY MODIFIED THE
HOURLY TEMP/DEWPOINT/WIND GRIDS BASED ON CURRENT OBS/TRENDS. THE
UPDATED PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT SUN SEP 8 2013
FORECAST CHALLENGES/HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE
THE COVERAGE AND AMOUNT OF PRECIPITATION NOW THROUGH TONIGHT
ALONG WITH ANOTHER ROUND OF SEVERE WEATHER.
CURRENTLY...UPPER LEVEL RIDGE AXIS CENTERED ACROSS THE DAKOTAS
THIS MORNING. CONVECTION CONTINUES TO BE VIGOROUS FROM ACROSS
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA...INTO SOUTH DAKOTA AND
WEST ACROSS SOUTHEAST MONTANA ALONG AN INSTABILITY AXIS AND IN THE
VICINITY OF A LOW LEVEL JET. AT THIS TIME STORMS ARE NON-
SEVERE...DUE IN PART TO RELATIVELY WEAK MID LEVEL LAPSE RATES.
ADDITIONAL SHOWERS/T-STORMS DEVELOPING OVER NORTHEAST MONTANA AND
EAST OVER NORTH CENTRAL AND NORTHEASTERN NORTH DAKOTA.
EXPECT THE CONVECTION OVER MONTANA TO SHIFT NORTH AND EAST INTO
WESTERN AND PORTIONS OF CENTRAL NORTH DAKOTA THIS MORNING AS A
POTENT LEAD S/WV IMPULSE NOW LIFTING ACROSS WYOMING MOVES INTO
EASTERN MONTANA 12-18Z...AND AS THE LLJ BECOMES MORE FOCUSED OVER
WESTERN ND BY 12Z AND SHIFTS EAST INTO CENTRAL ND LATER THIS
MORNING.
SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS MUCH OF THE REGION
TODAY INTO TONIGHT AS ADDITIONAL MID LEVEL WAVES LIFT NORTHEAST
ACROSS THE NORTHERN PLAINS...IN ADVANCE OF THE UPPER LOW (NOW
OVER NORTHERN IDAHO) AS IT TRACKS EAST ACROSS NORTHERN MONTANA. AT
THIS TIME EXPECT THE HEAVIER PRECIPITATION FROM THE AFTERNOON INTO
THE EVENING HOURS ACROSS NORTH DAKOTA WHEN DIFFLUENT FLOW ALOFT
LINKS TO STRONG THERMAL LIFT NORTH OF AN AREA OF LOW PRESSURE
ADVANCING NORTH AND EAST ACROSS SOUTH DAKOTA. THE STRONG SYNOPTIC
FORCING WILL COINCIDE WITH PLENTY OF INSTABILITY AND SHEAR TO
TRIGGER AT LEAST A FEW SEVERE STORMS THROUGH THE PERIOD.
IN ADDITION TO THE FORCING AND SEVERE PARAMETERS...MOISTURE
CONTINUES TO BE PUMPED FROM THE GULF OF MEXICO AROUND THE
SUBTROPICAL RIDGE INTO THE NORTHERN PLAINS. SURFACE TO 300MB
PRECIPITABLE WATER VALUES ARE CURRENTLY OVER 200 PERCENT OF NORMAL
FOR THIS TIME OF YEAR...AND ARE EXPECTED TO INCREASE TO NEAR 2
INCHES TODAY EXCEEDING THE MAXIMUM OBSERVED. THUS ANY STORMS WILL
HAVE THE POTENTIAL TO BE HEAVY RAINERS...SO WE HAVE EXTENDED THE
FLASH FLOOD WATCH THROUGH THIS SUNDAY NIGHT...AND EXPANDED THE
AERIAL COVERAGE TO INCLUDE ALL OF WEST AND CENTRAL NORTH DAKOTA.
ESPECIALLY PRONE TO FLASH FLOODING WILL BE PORTIONS OF WESTERN AND
SOUTHERN NORTH DAKOTA WHICH ALREADY SAW RAINFALL AMOUNTS UP TO
THREE INCHES THE PAST 12-24 HOURS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 415 AM CDT SUN SEP 8 2013
THE MEDIUM RANGE MODELS ARE RELATIVELY SLOWER WITH THE PROGRESSION
OF AN UPPER LEVEL LOW ACROSS NORTH DAKOTA MONDAY. THE LATEST
GUIDANCE NOW PIVOTS THE UPPER TROUGH AXIS ACROSS NORTH DAKOTA
MONDAY NIGHT (INSTEAD OF MONDAY AS GUIDANCE 24 HOURS AGO PROGGED).
AS A RESULT...KEPT CHANCE POPS IN FOR MONDAY...THEN FORECAST A
DECREASING POP TREND FROM SOUTHWEST TO NORTHEAST AS SUBSIDENCE
FILTERS IN BEHIND THE TROUGH AXIS MONDAY NIGHT. LINGERING SLIGHT
CHANCE POPS ARE FORECAST FOR BOTTINEAU...ROLETTE...AND PIERCE
COUNTIES TUESDAY MORNING. HOWEVER...LITTLE IMPACT IS EXPECTED.
DRY CONDITIONS ARE THEN EXPECTED AREAWIDE TUESDAY AFTERNOON THROUGH
FRIDAY AS UPPER LEVEL RIDGING BUILDS OVER THE NORTHERN ROCKIES AND
INTO THE NORTHERN PLAINS. ABOVE NORMAL TEMPERATURES ARE EXPECTED TO
CONTINUE THROUGH THE REMAINDER OF THE WORK WEEK.
ANOTHER ROUND OF PRECIPITATION IS FORECAST FOR SATURDAY AS AN UPPER
LEVEL SHORTWAVE EMANATING FROM THE ROCKIES IS PROGGED TO LIFT INTO
WESTERN NORTH DAKOTA. NOT REAL CONFIDENT WITH THE TIMING OF THIS
FEATURE AS THE MEDIUM RANGE MODELS HAVE RECENTLY BEEN STRUGGLING
WITH SHORTWAVE TIMING ISSUES. WILL CONTINUE TO MONITOR AND MAKE
ADJUSTMENTS AS NEEDED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1013 AM CDT SUN SEP 8 2013
AREA OF IFR CEILINGS AT KDIK HAS DISSIPATES. THUS VFR CONDITIONS
AT ALL BUT KISN...WHERE MVFR CEILINGS REMAIN. CEILINGS AT KISN
SHOULD LIFT TO VFR BY THE 18Z TAF ISSUANCE. EXPECT VFR CONDITIONS
THEN TO BEGIN THE TAF PERIOD WITH SCATTERED SHOWERS. SHOWER AND
THUNDERSTORM CHANCES WILL INCREASE PRECIPITATION CHANCES WILL
INCREASE FROM WEST TO EAST AGAIN LATER THIS AFTERNOON AND TONIGHT
WITH ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS...LASTING INTO
MONDAY MORNING ACROSS THE EAST.
&&
.HYDROLOGY...
ISSUED AT 415 AM CDT SUN SEP 8 2013
AS MENTIONED ABOVE IN THE SHORT TERM SECTION...HAVE EXPANDED AND
EXTENDED THE FLASH FLOOD WATCH TO INCLUDE ALL OF WESTERN AND
CENTRAL NORTH DAKOTA THROUGH TONIGHT. VERY HIGH ATMOSPHERIC
MOISTURE WILL LINE UP WITH FAVORABLE INSTABILITY AND SYNOPTIC
FORCING TO WARRANT THIS CHANGE. MODELS ARE PROJECTING PWAT VALUES
EXCEEDING THE MAXIMUM OBSERVED FOR THIS TIME OF THE SEASON...NEAR 2
INCHES ACROSS MUCH OF THE REGION.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH MONDAY MORNING FOR NDZ001>005-009>013-
017>023-025-031>037-040>048-050-051.
&&
$$
UPDATE...TWH
SHORT TERM...NH
LONG TERM...TM
AVIATION...TWH
HYDROLOGY...NH
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1004 AM CDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 1004 AM CDT SUN SEP 8 2013
FORECAST CONFIDENCE IS LOW AS MODELS HAVE PERFORMED POORLY WITH
ONGOING PRECIPITATION THIS MORNING. WILL FOLLOW THE HRRR FOR THE
MORNING UPDATE...WHICH BEST REFLECTS REALITY.
AREA OF MODERATE SHOWERS WITH ISOLATED EMBEDDED THUNDER STRETCHES
FROM NORTH OF ST. CLOUD TO JUST SOUTH OF GRAND FORKS AND IS IN AN
AREA OF ENHANCED 300 HPA DIVERGENCE AND 850 HPA FRONTOGENESIS.
HRRR SUGGESTS THIS CONVECTION WILL CONTINUE EASTWARD AND DISSIPATE
BY EARLY AFTERNOON. UPDATED POPS TO REFLECT THIS THINKING. ANOTHER
AREA OF SHOWERS STRETCHES FROM SOUTHWEST OF BISMARCK TO EAST OF
ABERDEEN. HRRR SHOWS THIS PRECIPITATION ALSO WEAKENING AS IT MOVES
EAST. HOWEVER...AM NOTICING SOME REDEVELOPMENT ACROSS THE SOUTHERN
VALLEY AS A REMNANT MCV EVIDENT IN RADAR REFLECTIVITY MOVES INTO
THE ND/SD/MN BORDER REGION. WILL NEED TO WATCH THIS FOR THE NEXT
UPDATE...BUT DO NOT ANTICIPATE ANY STRONGER STORMS WITH INSTABILITY
MAXIMIZED FARTHER SOUTH ACROSS WESTERN SD.
OVERALL...ONCE BAND OF SHOWERS/STORMS MOVES OUT OF WEST CENTRAL
MN...THINK THUNDERSTORM COVERAGE WILL BE SCATTERED FOR THE REST
OF THE MORNING AND AFTERNOON AS THE PRIMARY FORCING REMAINS WEST
OF THE FORECAST AREA. ATTENTION TONIGHT WILL TURN TO FLOODING AND
SEVERE POTENTIAL. UPDATED POPS AND WX THOUGH 00 UTC AND ALSO
DECREASED TEMPERATURES A FEW DEGREES WITH PERSISTENT CLOUD COVER.
AFTERNOON HIGHS WILL REACH THE UPPER 60S ALONG THE INTERNATIONAL
BORDER TO THE UPPER 70S ALONG THE SD STATE LINE.
UPDATE ISSUED AT 659 AM CDT SUN SEP 8 2013
VERY COMPLEX PRECIP PATTERN THIS MORNING. NO MODEL HANDLING IT
WELL SO GOING OFF CURRENT RADAR AND ADJUSTING FOR A FEW HOURS
AHEAD FOR IMMEDIATE UPDATES. MAIN MCS DWINDLED IN SE ND/NE SD AS
EXPECTED...BUT OUT AHEAD OF IT SOME CONVECTION FORMED IN THE FARGO
AREA PRODUCING UP TO 1 INCH OF RAIN QUICKLY. THIS CLUSTER MOVING
EAST INTO DTL-FFM AREAS. DID UP POPS REST OF THIS MORNING INTO
WCNTRL MN FOR THIS. OTHERWISE MORE SCATTERED LIGHT ACTIVITY
NORTHWARD INTO THE NRN VALLEY. WOULD APPEAR THIS AFTN TO SEE
SCATTERED ACTIVITY BUT MOST OF THE FOCUS WILL WAIT TIL OVERNIGHT.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 324 AM CDT SUN SEP 8 2013
THREAT FOR HEAVY RAIN TONIGHT IS THERE...BUT WHERE AND HOW MUCH IS
THE MAIN QUESTION. MODEL QPF HAS BEEN RATHER POOR LATELY SO
CONFIDENCE IN AMOUNTS AND EXACT PLACEMENT POOR.
CURRENTLY...HAVE REMAINS OF TSTM COMPLEX THAT WAS IN SW/SCNTRL
ND/NRN SD MOVING EAST SLOWLY AND WEAKENING AS IT ENTERS THE
ABERDEEN-OAKES AREA. BUT HRRR DOES TAKE SOME SHOWERS EAST ACROSS
THE SD/ND BORDER REGION INTO WCNTRL THIS MORNING SO INCLUDED POPS
FOR THIS. HOWEVER IT IS RUNNING INTO QUITE A BIT OF DRY AIR SOON
AND SHOULD START TO REALLY WEAKEN.
MODELS 12Z SAT AND 00Z SUN INDICATED TSTM COMPLEX IN WCNTRL OR NW
ND AT THIS TIME AND INSTEAD DEVELOPMENT HAS BEEN FARTHER SOUTH IN
A NARROW 850 MB LOW LEVEL JET ZONE IN THE DICKINSON-HETTINGER-
BOWMAN AREA OF ND INTO NW SD. THUS PREV FCST IDEA OF LIKELY POPS
SPREADING INTO DVL BASIN THIS MORNING SEEMS A BIT OFF AND REDUCED
POPS TO HIGH CHANCE. RADAR HAS BEEN SHOWING SOME VERY LIGHT
SHOWERS FROM THE MID LEVEL CLOUD COVER MOVING INTO DVL BASIN BUT
WIDESPREAD RAINFALL NOT ANTICIPATED AS FOCUS WILL CONTINUE TO BE
MORE IN SW ND AND THEN INTO CNTRL ND TODAY WITH LOW LEVEL 850 MB
JET AND MOISTURE.
TONIGHT IS THE MAIN ACTION AS SHORT WAVE LIFTS NORTHEAST FROM
MONTANA TROUGH INTO WRN ND AND SFC LOW IS STILL FCST TO TRACK FROM
WRN SD INTO FAR NE SD/SE ND BY 12Z MON. ALL INDICATIONS STILL
FAVOR A LARGE TSTM COMPLEX NORTHWEST OF SFC LOW FROM SW-CNTRL INTO
NE ND/FAR NW MN/SRN MANITOBA OVERNIGHT INTO MONDAY MORNING. KEPT
IDEA OF HVY RAIN MENTIONED IN GRIDDS AND CATEGORICAL POPS MAINLY
NORTH OF A VALLEY CITY-FARGO-BEMIDJI AREAS. GFS IS QUITE STRONG
WITH LOW LEVEL JET (40 KTS) AND HAS MAX 850 INSTABILITY GRADIENT IN
SE-ECNTRL ND-WCNTRL MN 09Z-12Z MON PERIOD AND THUS IDEA OF
ELEVATED SVR VERY POSSIBLE ALONG SRN EDGE OF ANY MCS. FOR RAINFALL
PWATS OF 2 INCHES AT 12Z MON WOULD ARGUE FOR WIDESPREAD 1-2 INCH
RAIN POTENTIAL IN MCS AREA WITH LOCALLY HEAVIER AMOUNTS.
CONSIDERING PAST 60-90 DAYS HAVE BEEN VERY DRY IN OUR REGION RAIN
WILL SOAK INTO THE GROUND WITH RUNOFF MORE LIMITED TO CITY-URBAN
AREAS. AND WITH STILL UNCERTAINTY DUE TO POOR MODEL QPF
PERFORMANCES OF LATE AND THE FACT THAT MAIN RAIN IS TONIGHT HELD
OFF ON ANY FLASH FLOOD WATCHES. BUT SOME MAY BE NEEDED ONCE HVY
RAIN AREA CAN BE PEGGED BETTER.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 324 AM CDT SUN SEP 8 2013
500 MB UPPER TROUGH TO MOVE OVER MANITOBA/NE ND/NW MN MON NIGHT-
TUES AND THUS WILL LEAVE IN LOW POPS FOR THIS.
WEDNESDAY-SATURDAY...BROAD CANADIAN SFC HIGH PRESSURE WILL DROP FROM
CENTRAL CANADA INTO THE GREAT LAKES MID TO LATE WEEK WITH NORTHWEST
FLOW ALOFT...KEEPING THE AREA DRY. MORE SEASONABLE HIGH TEMPS IN
THE 60S TO LOW 70S ARE EXPECTED BY THURSDAY/FRIDAY. THE COOLEST
NIGHT DURING THE PERIOD LOOKS TO BE THURSDAY NIGHT...AS THE SFC HIGH
APPROACHES. TEMPS SHOULD EASILY FALL INTO THE 40S...BUT IT IS
POSSIBLE THAT THESE TEMPS MAY BE TOO WARM...DEPENDING ON THE
EVENTUAL POSITION OF THE SFC HIGH.
BY EARLY NEXT WEEKEND MORE DISAGREEMENT EXISTS AMONG MODELS WITH THE
PATTERN EVOLUTION. HOWEVER...BOTH THE GFS/ECMWF DO BRING A SHORTWAVE
TROUGH INTO THE PLAINS ON SATURDAY...PERHAPS PROVIDING THE NEXT
OPPORTUNITY FOR SOME PRECIPITATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 1004 AM CDT SUN SEP 8 2013
ALL TAF SITES WILL BE IMPACTED BY PRECIP AT SOME POINT THE NEXT 24
HOURS. TIMING OF COURSE VERY DIFFICULT. SHOWER CLUSTER IN F-M AREA
MOVING EAST AND SPREADING NORTHEAST SOME SO WOULD EXPECT GFK-TVF TO
HAVE RAIN CHC INCREASE THRU 15Z. SOME SPOTTY MVFR CIGS IN THE WEST
THIS MORNING COULD EXPAND TO THE EAST...AND MAY HAVE TO ADD...AND
WILL MONITOR. BALANCE OF THE AFTN MORE DRY THAN WET....THEN HIT TSTM
CHANCES LATER TONIGHT ESP NRN VALLEY. ONCE STEADIER SHOWERS AND
STORMS DEVELOP OVERNIGHT...SHOULD BE MORE MVFR CONDITIONS AND EVEN
LOCALLY IFR NEAR STRONGER SHOWERS/STORMS...SO WILL CONTINUE TO
ADJUST AS WE HEAD THROUGH THIS EVENT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...RIDDLE
LONG TERM...MAKOWSKI/RIDDLE
AVIATION...DK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
705 AM CDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 659 AM CDT SUN SEP 8 2013
VERY COMPLEX PRECIP PATTERN THIS MORNING. NO MODEL HANDLING IT
WELL SO GOING OFF CURRENT RADAR AND ADJUSTING FOR A FEW HOURS
AHEAD FOR IMMEDIATE UPDATES. MAIN MCS DWINDLED IN SE ND/NE SD AS
EXPECTED...BUT OUT AHEAD OF IT SOME CONVECTION FORMED IN THE FARGO
AREA PRODUCING UP TO 1 INCH OF RAIN QUICKLY. THIS CLUSGTER MOVING
EAST INTO DTL-FFM AREAS. DID UP POPS REST OF THIS MORNING INTO
WCNTRL MN FOR THIS. OTHERWISE MORE SCATTERED LIGHT ACTIVITY
NORTHWARD INTO THE NRN VALLEY. WOULD APPEAR THIS AFTN TO SEE
SCATTERED ACTIVITY BUT MOST OF THE FOCUS WILL WAIT TIL OVERNIGHT.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 324 AM CDT SUN SEP 8 2013
THREAT FOR HEAVY RAIN TONIGHT IS THERE...BUT WHERE AND HOW MUCH IS
THE MAIN QUESTION. MODEL QPF HAS BEEN RATHER POOR LATELY SO
CONFIDENCE IN AMOUNTS AND EXACT PLACEMENT POOR.
CURRENTLY...HAVE REMAINS OF TSTM COMPLEX THAT WAS IN SW/SCNTRL
ND/NRN SD MOVING EAST SLOWLY AND WEAKENING AS IT ENTERS THE
ABERDEEN-OAKES AREA. BUT HRRR DOES TAKE SOME SHOWERS EAST ACROSS
THE SD/ND BORDER REGION INTO WCNTRL THIS MORNING SO INCLUDED POPS
FOR THIS. HOWEVER IT IS RUNNING INTO QUITE A BIT OF DRY AIR SOON
AND SHOULD START TO REALLY WEAKEN.
MODELS 12Z SAT AND 00Z SUN INDICATED TSTM COMPLEX IN WCNTRL OR NW
ND AT THIS TIME AND INSTEAD DEVELOPMENT HAS BEEN FARTHER SOUTH IN
A NARROW 850 MB LOW LEVEL JET ZONE IN THE DICKINSON-HETTINGER-
BOWMAN AREA OF ND INTO NW SD. THUS PREV FCST IDEA OF LIKELY POPS
SPREADING INTO DVL BASIN THIS MORNING SEEMS A BIT OFF AND REDUCED
POPS TO HIGH CHANCE. RADAR HAS BEEN SHOWING SOME VERY LIGHT
SHOWERS FROM THE MID LEVEL CLOUD COVER MOVING INTO DVL BASIN BUT
WIDESPREAD RAINFALL NOT ANTICIPATED AS FOCUS WILL CONTINUE TO BE
MORE IN SW ND AND THEN INTO CNTRL ND TODAY WITH LOW LEVEL 850 MB
JET AND MOISTURE.
TONIGHT IS THE MAIN ACTION AS SHORT WAVE LIFTS NORTHEAST FROM
MONTANA TROUGH INTO WRN ND AND SFC LOW IS STILL FCST TO TRACK FROM
WRN SD INTO FAR NE SD/SE ND BY 12Z MON. ALL INDICATIONS STILL
FAVOR A LARGE TSTM COMPLEX NORTHWEST OF SFC LOW FROM SW-CNTRL INTO
NE ND/FAR NW MN/SRN MANITOBA OVERNIGHT INTO MONDAY MORNING. KEPT
IDEA OF HVY RAIN MENTIONED IN GRIDDS AND CATEGORICAL POPS MAINLY
NORTH OF A VALLEY CITY-FARGO-BEMIDJI AREAS. GFS IS QUITE STRONG
WITH LOW LEVEL JET (40 KTS) AND HAS MAX 850 INSTABLITY GRADIENT IN
SE-ECNTRL ND-WCNTRL MN 09Z-12Z MON PERIOD AND THUS IDEA OF
ELEVATED SVR VERY POSSIBLE ALONG SRN EDGE OF ANY MCS. FOR RAINFALL
PWATS OF 2 INCHES AT 12Z MON WOULD ARGUE FOR WIDESPREAD 1-2 INCH
RAIN POTENTIAL IN MCS AREA WITH LOCALLY HEAVIER AMOUNTS.
CONSIDERING PAST 60-90 DAYS HAVE BEEN VERY DRY IN OUR REGION RAIN
WILL SOAK INTO THE GROUND WITH RUNOFF MORE LIMITED TO CITY-URBAN
AREAS. AND WITH STILL UNCERTAINITY DUE TO POOR MODEL QPF
PERFORMANCES OF LATE AND THE FACT THAT MAIN RAIN IS TONIGHT HELD
OFF ON ANY FLASH FLOOD WATCHES. BUT SOME MAY BE NEEDED ONCE HVY
RAIN AREA CAN BE PEGGED BETTER.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 324 AM CDT SUN SEP 8 2013
500 MB UPPER TROUGH TO MOVE OVER MANITOBA/NE ND/NW MN MON NIGHT-
TUES AND THUS WILL LEAVE IN LOW POPS FOR THIS.
WEDNESDAY-SATURDAY...BROAD CANADIAN SFC HIGH PRESSURE WILL DROP FROM
CENTRAL CANADA INTO THE GREAT LAKES MID TO LATE WEEK WITH NORTHWEST
FLOW ALOFT...KEEPING THE AREA DRY. MORE SEASONABLE HIGH TEMPS IN
THE 60S TO LOW 70S ARE EXPECTED BY THURSDAY/FRIDAY. THE COOLEST
NIGHT DURING THE PERIOD LOOKS TO BE THURSDAY NIGHT...AS THE SFC HIGH
APPROACHES. TEMPS SHOULD EASILY FALL INTO THE 40S...BUT IT IS
POSSIBLE THAT THESE TEMPS MAY BE TOO WARM...DEPENDING ON THE
EVENTUAL POSITION OF THE SFC HIGH.
BY EARLY NEXT WEEKEND MORE DISAGREEMENT EXISTS AMONG MODELS WITH THE
PATTERN EVOLUTION. HOWEVER...BOTH THE GFS/ECMWF DO BRING A SHORTWAVE
TROUGH INTO THE PLAINS ON SATURDAY...PERHAPS PROVIDING THE NEXT
OPPORTUNITY FOR SOME PRECIPITATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 659 AM CDT SUN SEP 8 2013
ALL TAF SITES WILL BE IMPCATED BY PRECIP AT SOME POINT THE NEXT 24
HOURS. TIMING OF COURSE VERY DIFFICULT. SHOWER CLUSTER IN F-M AREA
MOVING EAST AND SPREADING NORTHEAST SOME SO WOULD EXPECT GFK-TVF
TO HAVE RAIN CHC INCREASE THRU 15Z. SOME SPOTTY MVFR CIGS ALSO
DEVELOPING IN SE ND AND THIS MAY IMPACT SOME SPOTS THIS MORNING.
BALANCE OF THE AFTN MORE DRY THAN WET....THEN HIT TSTM CHANCES
LATER TONIGHT ESP NRN VALLEY. MIX OF CIGS THIS AFTN-
TONIGHT...THINKING VFR CIGS MOST AREAS THIS AFTN WITH SOME MVFR
CIGS LIKELY IN RAIN AREAS OVERNIGHT. WINDS MAINLY EAST-SOUTHEAST 5
TO 15 KTS...OCNL GUST TO 20 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...RIDDLE
LONG TERM...MAKOWSKI/RIDDLE
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1137 PM EDT MON SEP 9 2013
.SYNOPSIS...
A WARM FRONT DRAPED ACROSS WESTERN PENNSYLVANIA THIS EVENING WILL
PUSH THROUGH THE ENTIRE REGION EARLY TUESDAY MORNING. UNSEASONABLY
HOT AND HUMID CONDITIONS ARE EXPECTED THROUGH MIDWEEK WITH
SCATTERED SHOWERS AND THUNDERSTORMS. A SIGNIFICANT COOLING TREND
IS EXPECTED BEHIND A COLD FRONT WITH BELOW NORMAL TEMPERATURES
FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SFC ANALYSIS PLACES WARM FRONT ACROSS WESTERN PA LATE THIS
EVENING. JUST TO THE NE...EDGE OF THE WARM ADVECTION IS PRODUCING
ABUNDANT CLOUD COVER AND A FEW SHRA ACROSS CENTRAL PA. A FEW
LIGHTNING STRIKES NOTED OVR INDIANA CO AT 02Z...SO HAVE ADDED CHC
OF TSRA ACROSS THE LAUREL HIGHLANDS. HOWEVER...BEST INSTABILITY
REMAINS WEST OF THE ALLEGHENY RIDGE...SO WILL NOT MENTION TSRA
ELSEWHERE.
WILL CARRY LIKELY POPS THRU MIDNIGHT ALONG PORTIONS OF THE I-80
CORRIDOR BASED ON LATEST RADAR TRENDS. THE ENTIRE REGION STANDS
THE CHC OF SEEING A SHOWER OR TWO LATER TONIGHT AS WARM FRONT
PUSHES INTO THE AREA. HOWEVER...WILL KEEP LATE NIGHT POPS ON THE
LOW SIDE BASED ON OPER AND ENSEMBLE QPF.
ANOTHER ISSUE CONCERNS THE POTENTIAL OF FOG LATE TONIGHT. AREA
MOST LIKELY TO SEE SIG VSBY REDUCTIONS WILL BE JUST NORTH OF THE
WARM FRONT ACROSS NE PA. LATEST SREF AND RAP SUPPORT THIS SCENARIO
WITH THE NE COUNTIES SEEING THE HIGHEST PROBS OF LOW VSBY AND
HIGHEST SFC RH/S RESPECTIVELY.
CLOUD COVER AND INCREASING HUMIDITY WILL LEAD TO A MUCH MILDER
NIGHT WITH LOWS RANGING FROM THE U50S ACROSS THE N MTNS...TO BTWN
60-65F ELSEWHERE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
WARM FRONT SHOULD PUSH NE OF THE ENTIRE AREA BY LATE AM...BRINGING
CLEARING SKIES AND RAPIDLY RISING TEMPS. BASED ON UPSTREAM CONDS THIS
AFTN ACROSS THE UPPER MIDWEST...LOOKS LIKE MID SUMMER HEAT AND
HUMIDITY BY TUE AFTN WITH HIGHS APPROACHING 90F IN MANY LOCATIONS.
AN ISOLATED PM SHOWER OR STORM CANNOT BE RULED OUT BUT WITH MODEL
FCST TEMPS IN THE MID LEVELS TOPPING 10C...THE CAP WILL BE PRETTY
HARD TO BREAK. WILL KEEP POPS OF ONLY ARND 10 PCT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
PARTLY TO MOSTLY CLOUDY SKIES TUESDAY NIGHT WITHIN THE EXTENSIVE
WARM SECTOR...WILL COMBINE WITH A SOUTHERLY LIGHT WIND AND SFC
DEWPOINTS IN THE MID TO UPPER 60S...LEADING TO A MUGGY NIGHT WITH
JUST A SCHC FOR TSRA PERSISTING ACROSS NRN PENN.
LIKELY THE HOTTEST DAY UNTIL LATER NEXT SPRING OR SUMMER WILL OCCUR
WEDNESDAY...WITH HIGH TEMPS REACHING INTO THE MID 80S /MTNS/ AND
LOWER 90S ACROSS THE LOWER SUSQ VALLEY.
A PRE-FRONTAL/LEE TROF WILL LIKELY DEVELOP ACROSS THE SUSQ VALLEY
WEDNESDAY...HELPING TO FOCUS THE BEST CHC FOR AT LEAST SCATTERED
AFTERNOON TSRA THERE. ACROSS THE NW...THE FIRST OF TWO SFC CFRONTS
WILL APPROACH LATER IN THE DAY/EVENING...SPARKING A BKN BAND OF
SHOWERS AND SCATTERED TSRA.
THE PAIR OF COLD FRONTS WILL MOVES SE ACROSS THE STATE WED NIGHT AND
THURSDAY...WITH ANOTHER ROUND OR TO OF SHOWERS/TSRA. FOR LATE IN THE
WEEK AND OVER THE UPCOMING WEEKEND...A SPRAWLING/COOL CANADIAN HIGH
AND ANOMALOUSLY DEEP UPPER TROUGH WILL MOVE SOUTHEAST FROM THE
GLAKES...BRINGING A RETURN TO MUCH LOWER DEWPOINTS AND BELOW NORMAL
TEMPS.
THE ZERO C 850 MB ISOTHERM /IN THE LATEST...03Z SREF/ WILL MOVE OVER
THE NRN GREAT LAKES REGION THURSDAY...BEFORE DIVING SOUTHEAST TO
MAKE A RARE EARLY SEASON APPEARANCE NEAR THE PENN/NEW YORK BORDER
AND SOUTHERN NEW ENGLAND COAST FRIDAY INTO EARLY SATURDAY. THESE -2
TO -3 SIGMA TEMPS AT 850 MB WILL UNDOUBTEDLY LEAD TO WIDESPREAD COLD
AIR STRATO CU WITH LAKE EFFECT AND OROGRAPHICALLY ENHANCED SHOWERS.
WE MAY BE UNDERPLAYING THE AMOUNT OF CLOUDS AND POPS FOR FRIDAY AND
SATURDAY HERE IN CENTRAL AND NRN PENN WITHIN THE COLD...GUSTY AND
WELL-ALIGNED DEEP NWRLY FLOW.
SO...IN SUMMARY...THE MAIN STORIES FOR THIS PERIOD WILL BE THE HEAT
TO START...SCATTERED STRONG TO SEVERE STORMS POSSIBLE LATER TUESDAY
AND WEDNESDAY...MAINLY NORTH OF THE REGION/...AND THE UNSEASONABLY
CHILLY AIRMASS TO CLOSE IT OUT.
&&
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
ONLY A FEW ADJUSTMENTS BASED ON CURRENT RADAR.
EARLIER DISCUSSION BELOW.
FEW LOWER CLDS AT TIMES EARLIER THIS AFT IN RETURN FLOW.
MAIN THING OVERNIGHT WILL BE A FEW SHOWERS...PERHAPS A
RUMBLE OF THUNDER...AS WARM FRONT MOVES INTO THE AREA. VERY
HOT AIRMASS TO THE WEST...DEWPOINTS QUITE HIGH...THUS WILL
HAVE TO MONITOR FOR NEW STORM DEVELOPMENT TO THE WEST.
WENT WITH VFR CONDITIONS ON TUE. EML TYPE AIRMASS WILL LIKELY
KEEP MID LVL TEMPS WARM ENOUGH TO PREVENT SHOWERS AND STORM
FORMATION...SO LEFT THEM OUT OF THE TAFS FOR NOW.
IT WILL BE BREEZY OUT...ESPECIALLY ACROSS NW PA...GIVEN BLAST
OF HOT AIR FROM THE PLAINS.
SIMILAR CONDITIONS FOR WED...MORE IN THE WAY OF A CHC OF A
SHOWER OR STORM...ESPECIALLY LATE...AS THE COLD FRONT NEARS.
MUCH COOLER AND BREEZY CONDITIONS FOR LATE WEEK...AS HIGH
PRESSURE BUILDS SE FROM CANADA.
OUTLOOK...
WED...SCT PM TSTM IMPACTS PSBL.
THU...SCT-NMRS TSTM IMPACTS PSBL WITH COLD FROPA.
FRI...MVFR/SCT SHOWERS PSBL N/W...VFR CENTRAL/EAST.
SAT...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD/LA CORTE
NEAR TERM...FITZGERALD/LA CORTE
SHORT TERM...FITZGERALD/LA CORTE
LONG TERM...GARTNER/MARTIN
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1018 PM EDT MON SEP 9 2013
.SYNOPSIS...
A WARM FRONT DRAPED ACROSS WESTERN PENNSYLVANIA THIS EVENING WILL
PUSH THROUGH THE ENTIRE REGION EARLY TUESDAY MORNING. UNSEASONABLY
HOT AND HUMID CONDITIONS ARE EXPECTED THROUGH MIDWEEK WITH
SCATTERED SHOWERS AND THUNDERSTORMS. A SIGNIFICANT COOLING TREND
IS EXPECTED BEHIND A COLD FRONT WITH BELOW NORMAL TEMPERATURES
FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SFC ANALYSIS PLACES WARM FRONT ACROSS WESTERN PA LATE THIS
EVENING. JUST TO THE NE...EDGE OF THE WARM ADVECTION IS PRODUCING
ABUNDANT CLOUD COVER AND A FEW SHRA ACROSS CENTRAL PA. A FEW
LIGHTNING STRIKES NOTED OVR INDIANA CO AT 02Z...SO HAVE ADDED CHC
OF TSRA ACROSS THE LAUREL HIGHLANDS. HOWEVER...BEST INSTABILITY
REMAINS WEST OF THE ALLEGHENY RIDGE...SO WILL NOT MENTION TSRA
ELSEWHERE.
WILL CARRY LIKELY POPS THRU MIDNIGHT ALONG PORTIONS OF THE I-80
CORRIDOR BASED ON LATEST RADAR TRENDS. THE ENTIRE REGION STANDS
THE CHC OF SEEING A SHOWER OR TWO LATER TONIGHT AS WARM FRONT
PUSHES INTO THE AREA. HOWEVER...WILL KEEP LATE NIGHT POPS ON THE
LOW SIDE BASED ON OPER AND ENSEMBLE QPF.
ANOTHER ISSUE CONCERNS THE POTENTIAL OF FOG LATE TONIGHT. AREA
MOST LIKELY TO SEE SIG VSBY REDUCTIONS WILL BE JUST NORTH OF THE
WARM FRONT ACROSS NE PA. LATEST SREF AND RAP SUPPORT THIS SCENARIO
WITH THE NE COUNTIES SEEING THE HIGHEST PROBS OF LOW VSBY AND
HIGHEST SFC RH/S RESPECTIVELY.
CLOUD COVER AND INCREASING HUMIDITY WILL LEAD TO A MUCH MILDER
NIGHT WITH LOWS RANGING FROM THE U50S ACROSS THE N MTNS...TO BTWN
60-65F ELSEWHERE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
WARM FRONT SHOULD PUSH NE OF THE ENTIRE AREA BY LATE AM...BRINGING
CLEARING SKIES AND RAPIDLY RISING TEMPS. BASED ON UPSTREAM CONDS THIS
AFTN ACROSS THE UPPER MIDWEST...LOOKS LIKE MID SUMMER HEAT AND
HUMIDITY BY TUE AFTN WITH HIGHS APPROACHING 90F IN MANY LOCATIONS.
AN ISOLATED PM SHOWER OR STORM CANNOT BE RULED OUT BUT WITH MODEL
FCST TEMPS IN THE MID LEVELS TOPPING 10C...THE CAP WILL BE PRETTY
HARD TO BREAK. WILL KEEP POPS OF ONLY ARND 10 PCT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
PARTLY TO MOSTLY CLOUDY SKIES TUESDAY NIGHT WITHIN THE EXTENSIVE
WARM SECTOR...WILL COMBINE WITH A SOUTHERLY LIGHT WIND AND SFC
DEWPOINTS IN THE MID TO UPPER 60S...LEADING TO A MUGGY NIGHT WITH
JUST A SCHC FOR TSRA PERSISTING ACROSS NRN PENN.
LIKELY THE HOTTEST DAY UNTIL LATER NEXT SPRING OR SUMMER WILL OCCUR
WEDNESDAY...WITH HIGH TEMPS REACHING INTO THE MID 80S /MTNS/ AND
LOWER 90S ACROSS THE LOWER SUSQ VALLEY.
A PRE-FRONTAL/LEE TROF WILL LIKELY DEVELOP ACROSS THE SUSQ VALLEY
WEDNESDAY...HELPING TO FOCUS THE BEST CHC FOR AT LEAST SCATTERED
AFTERNOON TSRA THERE. ACROSS THE NW...THE FIRST OF TWO SFC CFRONTS
WILL APPROACH LATER IN THE DAY/EVENING...SPARKING A BKN BAND OF
SHOWERS AND SCATTERED TSRA.
THE PAIR OF COLD FRONTS WILL MOVES SE ACROSS THE STATE WED NIGHT AND
THURSDAY...WITH ANOTHER ROUND OR TO OF SHOWERS/TSRA. FOR LATE IN THE
WEEK AND OVER THE UPCOMING WEEKEND...A SPRAWLING/COOL CANADIAN HIGH
AND ANOMALOUSLY DEEP UPPER TROUGH WILL MOVE SOUTHEAST FROM THE
GLAKES...BRINGING A RETURN TO MUCH LOWER DEWPOINTS AND BELOW NORMAL
TEMPS.
THE ZERO C 850 MB ISOTHERM /IN THE LATEST...03Z SREF/ WILL MOVE OVER
THE NRN GREAT LAKES REGION THURSDAY...BEFORE DIVING SOUTHEAST TO
MAKE A RARE EARLY SEASON APPEARANCE NEAR THE PENN/NEW YORK BORDER
AND SOUTHERN NEW ENGLAND COAST FRIDAY INTO EARLY SATURDAY. THESE -2
TO -3 SIGMA TEMPS AT 850 MB WILL UNDOUBTEDLY LEAD TO WIDESPREAD COLD
AIR STRATO CU WITH LAKE EFFECT AND OROGRAPHICALLY ENHANCED SHOWERS.
WE MAY BE UNDERPLAYING THE AMOUNT OF CLOUDS AND POPS FOR FRIDAY AND
SATURDAY HERE IN CENTRAL AND NRN PENN WITHIN THE COLD...GUSTY AND
WELL-ALIGNED DEEP NWRLY FLOW.
SO...IN SUMMARY...THE MAIN STORIES FOR THIS PERIOD WILL BE THE HEAT
TO START...SCATTERED STRONG TO SEVERE STORMS POSSIBLE LATER TUESDAY
AND WEDNESDAY...MAINLY NORTH OF THE REGION/...AND THE UNSEASONABLY
CHILLY AIRMASS TO CLOSE IT OUT.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
FEW LOWER CLDS AT TIMES EARLIER THIS AFT IN RETURN FLOW.
MAIN THING OVERNIGHT WILL BE A FEW SHOWERS...PERHAPS A
RUMBLE OF THUNDER...AS WARM FRONT MOVES INTO THE AREA. VERY
HOT AIRMASS TO THE WEST...DEWPOINTS QUITE HIGH...THUS WILL
HAVE TO MONITOR FOR NEW STORM DEVELOPMENT TO THE WEST.
WENT WITH VFR CONDITIONS ON TUE. EML TYPE AIRMASS WILL LIKELY
KEEP MID LVL TEMPS WARM ENOUGH TO PREVENT SHOWERS AND STORM
FORMATION...SO LEFT THEM OUT OF THE TAFS FOR NOW.
IT WILL BE BREEZY OUT...ESPECIALLY ACROSS NW PA...GIVEN BLAST
OF HOT AIR FROM THE PLAINS.
SIMILAR CONDITIONS FOR WED...MORE IN THE WAY OF A CHC OF A
SHOWER OR STORM...ESPECIALLY LATE...AS THE COLD FRONT NEARS.
MUCH COOLER AND BREEZY CONDITIONS FOR LATE WEEK...AS HIGH
PRESSURE BUILDS SE FROM CANADA.
OUTLOOK...
WED...SCT PM TSTM IMPACTS PSBL.
THU...SCT-NMRS TSTM IMPACTS PSBL WITH COLD FROPA.
FRI...MVFR/SCT SHOWERS PSBL N/W...VFR CENTRAL/EAST.
SAT...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD/LA CORTE
NEAR TERM...FITZGERALD/LA CORTE
SHORT TERM...FITZGERALD/LA CORTE
LONG TERM...GARTNER/MARTIN
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
812 PM EDT MON SEP 9 2013
.SYNOPSIS...
A WARM FRONT DRAPED ACROSS WESTERN PENNSYLVANIA THIS EVENING WILL
PUSH THROUGH THE ENTIRE REGION EARLY TUESDAY MORNING. UNSEASONABLY
HOT AND HUMID CONDITIONS ARE EXPECTED THROUGH MIDWEEK WITH
SCATTERED SHOWERS AND THUNDERSTORMS. A SIGNIFICANT COOLING TREND
IS EXPECTED BEHIND A COLD FRONT WITH BELOW NORMAL TEMPERATURES
FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SFC ANALYSIS PLACES WARM FRONT ACROSS WESTERN PA EARLY THIS
EVENING. HEATING OF WARM/HUMID AIR MASS WEST OF FRONT HAS RESULTED
IN CAPES NR 1000 J/KG /23Z SPC MESOANALYSIS/ AND SCT TSRA IN THE
VICINITY OF PITTSBURGH. JUST TO THE NE...EDGE OF THE WARM
ADVECTION IS PRODUCING ABUNDANT CLOUD COVER AND A FEW SHRA ACROSS
CENTRAL PA.
ANY TSRA WILL VERY LIKELY DIE...AS THEY DRIFT TOWARD MORE STABLE
AIR MASS ACROSS THE LAUREL HIGHLANDS THIS EVENING. HOWEVER...HAVE
RAISED POPS CONSIDERABLY ACROSS THE NORTH CENTRAL PA BASED ON
LATEST RADAR TRENDS. THE ENTIRE REGION STANDS THE CHC OF SEEING A
SHOWER OR TWO OVERNIGHT AS WARM FRONT PUSHES INTO THE AREA.
HOWEVER...WITH EXCEPTION OF EVENING SHOWERS OVR THE NORTH CENTRAL
COUNTIES...WILL KEEP POPS ON THE LOW SIDE BASED ON OPER AND
ENSEMBLE QPF.
ANOTHER ISSUE CONCERNS THE POTENTIAL OF FOG LATE TONIGHT. AREA
MOST LIKELY TO SEE SIG VSBY REDUCTIONS WILL BE JUST NORTH OF THE
WARM FRONT ACROSS NE PA. LATEST SREF AND RAP SUPPORT THIS SCENARIO
WITH THE NE COUNTIES SEEING THE HIGHEST PROBS OF LOW VSBY AND
HIGHEST SFC RH/S RESPECTIVELY.
CLOUD COVER AND INCREASING HUMIDITY WILL LEAD TO A MUCH MILDER
NIGHT WITH LOWS RANGING FROM THE U50S ACROSS THE NE COUNTIES...TO
BTWN 60-65F ELSEWHERE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
WARM FRONT SHOULD PUSH NE OF THE ENTIRE AREA BY LATE AM...BRINGING
CLEARING SKIES AND RAPIDLY RISING TEMPS. BASED ON UPSTREAM CONDS THIS
AFTN ACROSS THE UPPER MIDWEST...LOOKS LIKE MID SUMMER HEAT AND
HUMIDITY BY TUE AFTN WITH HIGHS APPROACHING 90F IN MANY LOCATIONS.
AN ISOLATED PM SHOWER OR STORM CANNOT BE RULED OUT BUT WITH MODEL
FCST TEMPS IN THE MID LEVELS TOPPING 10C...THE CAP WILL BE PRETTY
HARD TO BREAK. WILL KEEP POPS OF ONLY ARND 10 PCT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
PARTLY TO MOSTLY CLOUDY SKIES TUESDAY NIGHT WITHIN THE EXTENSIVE
WARM SECTOR...WILL COMBINE WITH A SOUTHERLY LIGHT WIND AND SFC
DEWPOINTS IN THE MID TO UPPER 60S...LEADING TO A MUGGY NIGHT WITH
JUST A SCHC FOR TSRA PERSISTING ACROSS NRN PENN.
LIKELY THE HOTTEST DAY UNTIL LATER NEXT SPRING OR SUMMER WILL OCCUR
WEDNESDAY...WITH HIGH TEMPS REACHING INTO THE MID 80S /MTNS/ AND
LOWER 90S ACROSS THE LOWER SUSQ VALLEY.
A PRE-FRONTAL/LEE TROF WILL LIKELY DEVELOP ACROSS THE SUSQ VALLEY
WEDNESDAY...HELPING TO FOCUS THE BEST CHC FOR AT LEAST SCATTERED
AFTERNOON TSRA THERE. ACROSS THE NW...THE FIRST OF TWO SFC CFRONTS
WILL APPROACH LATER IN THE DAY/EVENING...SPARKING A BKN BAND OF
SHOWERS AND SCATTERED TSRA.
THE PAIR OF COLD FRONTS WILL MOVES SE ACROSS THE STATE WED NIGHT AND
THURSDAY...WITH ANOTHER ROUND OR TO OF SHOWERS/TSRA. FOR LATE IN THE
WEEK AND OVER THE UPCOMING WEEKEND...A SPRAWLING/COOL CANADIAN HIGH
AND ANOMALOUSLY DEEP UPPER TROUGH WILL MOVE SOUTHEAST FROM THE
GLAKES...BRINGING A RETURN TO MUCH LOWER DEWPOINTS AND BELOW NORMAL
TEMPS.
THE ZERO C 850 MB ISOTHERM /IN THE LATEST...03Z SREF/ WILL MOVE OVER
THE NRN GREAT LAKES REGION THURSDAY...BEFORE DIVING SOUTHEAST TO
MAKE A RARE EARLY SEASON APPEARANCE NEAR THE PENN/NEW YORK BORDER
AND SOUTHERN NEW ENGLAND COAST FRIDAY INTO EARLY SATURDAY. THESE -2
TO -3 SIGMA TEMPS AT 850 MB WILL UNDOUBTEDLY LEAD TO WIDESPREAD COLD
AIR STRATO CU WITH LAKE EFFECT AND OROGRAPHICALLY ENHANCED SHOWERS.
WE MAY BE UNDERPLAYING THE AMOUNT OF CLOUDS AND POPS FOR FRIDAY AND
SATURDAY HERE IN CENTRAL AND NRN PENN WITHIN THE COLD...GUSTY AND
WELL-ALIGNED DEEP NWRLY FLOW.
SO...IN SUMMARY...THE MAIN STORIES FOR THIS PERIOD WILL BE THE HEAT
TO START...SCATTERED STRONG TO SEVERE STORMS POSSIBLE LATER TUESDAY
AND WEDNESDAY...MAINLY NORTH OF THE REGION/...AND THE UNSEASONABLY
CHILLY AIRMASS TO CLOSE IT OUT.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
FEW LOWER CLDS AT TIMES EARLIER THIS AFT IN RETURN FLOW.
MAIN THING OVERNIGHT WILL BE A FEW SHOWERS...PERHAPS A
RUMBLE OF THUNDER...AS WARM FRONT MOVES INTO THE AREA. VERY
HOT AIRMASS TO THE WEST...DEWPOINTS QUITE HIGH...THUS WILL
HAVE TO MONITOR FOR NEW STORM DEVELOPMENT TO THE WEST.
WENT WITH VFR CONDITIONS ON TUE. EML TYPE AIRMASS WILL LIKELY
KEEP MID LVL TEMPS WARM ENOUGH TO PREVENT SHOWERS AND STORM
FORMATION...SO LEFT THEM OUT OF THE TAFS FOR NOW.
IT WILL BE BREEZY OUT...ESPECIALLY ACROSS NW PA...GIVEN BLAST
OF HOT AIR FROM THE PLAINS.
SIMILAR CONDITIONS FOR WED...MORE IN THE WAY OF A CHC OF A
SHOWER OR STORM...ESPECIALLY LATE...AS THE COLD FRONT NEARS.
MUCH COOLER AND BREEZY CONDITIONS FOR LATE WEEK...AS HIGH
PRESSURE BUILDS SE FROM CANADA.
OUTLOOK...
WED...SCT PM TSTM IMPACTS PSBL.
THU...SCT-NMRS TSTM IMPACTS PSBL WITH COLD FROPA.
FRI...MVFR/SCT SHOWERS PSBL N/W...VFR CENTRAL/EAST.
SAT...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD/LA CORTE
NEAR TERM...FITZGERALD/LA CORTE
SHORT TERM...FITZGERALD/LA CORTE
LONG TERM...GARTNER/MARTIN
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
732 PM EDT MON SEP 9 2013
.SYNOPSIS...
A WARM FRONT DRAPED ACROSS WESTERN PENNSYLVANIA THIS EVENING WILL
PUSH THROUGH THE ENTIRE REGION EARLY TUESDAY MORNING. UNSEASONABLY
HOT AND HUMID CONDITIONS ARE EXPECTED THROUGH MIDWEEK WITH
SCATTERED SHOWERS AND THUNDERSTORMS. A SIGNIFICANT COOLING TREND
IS EXPECTED BEHIND A COLD FRONT WITH BELOW NORMAL TEMPERATURES
FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SFC ANALYSIS PLACES WARM FRONT ACROSS WESTERN PA EARLY THIS
EVENING. HEATING OF WARM/HUMID AIR MASS WEST OF FRONT HAS RESULTED
IN CAPES NR 1000 J/KG /23Z SPC MESOANALYSIS/ AND SCT TSRA IN THE
VICINITY OF PITTSBURGH. JUST TO THE NE...EDGE OF THE WARM
ADVECTION IS PRODUCING ABUNDANT CLOUD COVER AND A FEW SHRA ACROSS
CENTRAL PA.
ANY TSRA WILL VERY LIKELY DIE...AS THEY DRIFT TOWARD MORE STABLE
AIR MASS ACROSS THE LAUREL HIGHLANDS THIS EVENING. HOWEVER...HAVE
RAISED POPS CONSIDERABLY ACROSS THE NORTH CENTRAL PA BASED ON
LATEST RADAR TRENDS. THE ENTIRE REGION STANDS THE CHC OF SEEING A
SHOWER OR TWO OVERNIGHT AS WARM FRONT PUSHES INTO THE AREA.
HOWEVER...WITH EXCEPTION OF EVENING SHOWERS OVR THE NORTH CENTRAL
COUNTIES...WILL KEEP POPS ON THE LOW SIDE BASED ON OPER AND
ENSEMBLE QPF.
ANOTHER ISSUE CONCERNS THE POTENTIAL OF FOG LATE TONIGHT. AREA
MOST LIKELY TO SEE SIG VSBY REDUCTIONS WILL BE JUST NORTH OF THE
WARM FRONT ACROSS NE PA. LATEST SREF AND RAP SUPPORT THIS SCENARIO
WITH THE NE COUNTIES SEEING THE HIGHEST PROBS OF LOW VSBY AND
HIGHEST SFC RH/S RESPECTIVELY.
CLOUD COVER AND INCREASING HUMIDITY WILL LEAD TO A MUCH MILDER
NIGHT WITH LOWS RANGING FROM THE U50S ACROSS THE NE COUNTIES...TO
BTWN 60-65F ELSEWHERE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
WARM FRONT SHOULD PUSH NE OF THE ENTIRE AREA BY LATE AM...BRINGING
CLEARING SKIES AND RAPIDLY RISING TEMPS. BASED ON UPSTREAM CONDS THIS
AFTN ACROSS THE UPPER MIDWEST...LOOKS LIKE MID SUMMER HEAT AND
HUMIDITY BY TUE AFTN WITH HIGHS APPROACHING 90F IN MANY LOCATIONS.
AN ISOLATED PM SHOWER OR STORM CANNOT BE RULED OUT BUT WITH MODEL
FCST TEMPS IN THE MID LEVELS TOPPING 10C...THE CAP WILL BE PRETTY
HARD TO BREAK. WILL KEEP POPS OF ONLY ARND 10 PCT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
PARTLY TO MOSTLY CLOUDY SKIES TUESDAY NIGHT WITHIN THE EXTENSIVE
WARM SECTOR...WILL COMBINE WITH A SOUTHERLY LIGHT WIND AND SFC
DEWPOINTS IN THE MID TO UPPER 60S...LEADING TO A MUGGY NIGHT WITH
JUST A SCHC FOR TSRA PERSISTING ACROSS NRN PENN.
LIKELY THE HOTTEST DAY UNTIL LATER NEXT SPRING OR SUMMER WILL OCCUR
WEDNESDAY...WITH HIGH TEMPS REACHING INTO THE MID 80S /MTNS/ AND
LOWER 90S ACROSS THE LOWER SUSQ VALLEY.
A PRE-FRONTAL/LEE TROF WILL LIKELY DEVELOP ACROSS THE SUSQ VALLEY
WEDNESDAY...HELPING TO FOCUS THE BEST CHC FOR AT LEAST SCATTERED
AFTERNOON TSRA THERE. ACROSS THE NW...THE FIRST OF TWO SFC CFRONTS
WILL APPROACH LATER IN THE DAY/EVENING...SPARKING A BKN BAND OF
SHOWERS AND SCATTERED TSRA.
THE PAIR OF COLD FRONTS WILL MOVES SE ACROSS THE STATE WED NIGHT AND
THURSDAY...WITH ANOTHER ROUND OR TO OF SHOWERS/TSRA. FOR LATE IN THE
WEEK AND OVER THE UPCOMING WEEKEND...A SPRAWLING/COOL CANADIAN HIGH
AND ANOMALOUSLY DEEP UPPER TROUGH WILL MOVE SOUTHEAST FROM THE
GLAKES...BRINGING A RETURN TO MUCH LOWER DEWPOINTS AND BELOW NORMAL
TEMPS.
THE ZERO C 850 MB ISOTHERM /IN THE LATEST...03Z SREF/ WILL MOVE OVER
THE NRN GREAT LAKES REGION THURSDAY...BEFORE DIVING SOUTHEAST TO
MAKE A RARE EARLY SEASON APPEARANCE NEAR THE PENN/NEW YORK BORDER
AND SOUTHERN NEW ENGLAND COAST FRIDAY INTO EARLY SATURDAY. THESE -2
TO -3 SIGMA TEMPS AT 850 MB WILL UNDOUBTEDLY LEAD TO WIDESPREAD COLD
AIR STRATO CU WITH LAKE EFFECT AND OROGRAPHICALLY ENHANCED SHOWERS.
WE MAY BE UNDERPLAYING THE AMOUNT OF CLOUDS AND POPS FOR FRIDAY AND
SATURDAY HERE IN CENTRAL AND NRN PENN WITHIN THE COLD...GUSTY AND
WELL-ALIGNED DEEP NWRLY FLOW.
SO...IN SUMMARY...THE MAIN STORIES FOR THIS PERIOD WILL BE THE HEAT
TO START...SCATTERED STRONG TO SEVERE STORMS POSSIBLE LATER TUESDAY
AND WEDNESDAY...MAINLY NORTH OF THE REGION/...AND THE UNSEASONABLY
CHILLY AIRMASS TO CLOSE IT OUT.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
VIZ LOOP SHOWS LOW CLOUDS BUILDING IN THE WEAK UPSLOPE FLOW OVER
SOUTH CENTRAL PA. THE AOO CIG HAS ACTUALLY BEEN LOWERING DESPITE
WHAT LOOKS LIKE SOME MIXING STARTING TO DEVELOP IN THE LOW CLOUD
SHIELD. WOULD NOT BE SURPRISED TO EVEN SEE THE CEILING AT UNV GO
BRIEFLY MVFR BEFORE THE CLOUDS MIC AND BASES LIFT UP THIS
AFTERNOON.
THE LARGER PICTURE SHOWS AN INCREASINGLY MOIST SOUTHERLY FLOW
BEGINNING TO DEVELOP WHICH WILL BRING A CHANCE OF A SHOWER OR
THUNDERSTORM LATER TODAY INTO TONIGHT...MAINLY OVER WESTERN
AREAS.
MVFR/IFR CIGS ARE LIKELY ACROSS THE SERN TERMINALS LATE
TONIGHT. LOW CIGS WILL IMPROVE EARLY TUES GIVING WAY TO VFR BY
TUES AFTERNOON.
OUTLOOK...
TUE...AM LOW CLOUDS SOUTH/EAST.
WED...SCT PM TSTM IMPACTS PSBL.
THU...SCT-NMRS TSTM IMPACTS PSBL WITH COLD FROPA.
FRI...MVFR/SCT SHOWERS PSBL N/W...VFR CENTRAL/EAST.
SAT...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD/LA CORTE
NEAR TERM...FITZGERALD/LA CORTE
SHORT TERM...FITZGERALD/LA CORTE
LONG TERM...GARTNER/MARTIN
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
434 PM EDT SUN SEP 8 2013
.SYNOPSIS...
A COLD FRONT DROPPING SOUTH THROUGH THE STATE WILL USHER IN A
COOLER AND DRIER NORTHERLY FLOW FOR TONIGHT AND MONDAY.
TEMPERATURES WILL QUICKLY RECOVER ON TUESDAY AS A WARM FRONT LIFTS
NORTH ACROSS THE AREA. UNSEASONABLY WARM AND HUMID SUMMER-LIKE
WEATHER IS EXPECTED THROUGH MIDWEEK BEFORE A COLD FRONT MOVES
THROUGH ON THURSDAY. FAIR WEATHER AND SEASONABLY COOL TEMPERATURES
SHOULD RETURN BY THE END OF THE WEEK AS ANOTHER REFRESHING FALL-
LIKE CANADIAN AIR MASS MOVES INTO THE REGION.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
CLEARING SKIES TAKING PLACE EARLY THIS EVENING...AS COLD FRONT
PUSHES SOUTH OF THE AREA AND MUCH DRIER AIR NOW FLOWING INTO THE
STATE ON A NORTHERLY FLOW. LATEST RAP RH FIELDS SUGGEST LINGERING
CU ACROSS SOUTHERN PA WILL DRY UP BY 00Z...LEAVING CLEAR SKIES
FOR THE REST OF THE NIGHT.
THE MODIFIED CANADIAN AIR MASS ACCOMPANYING THIS HIGH PRES SYSTEM IS
NOT QUITE AS COOL AND CHILLY AS THE ONE OF A FEW DAYS PAST.
HOWEVER...STILL CANT RULE OUT SOME PATCHY FROST ACROSS THE COLDER
POCKETS OF THE NRN MTNS WHERE MINS SHOULD DIP INTO THE UPPER 30S
TO AROUND 40F. MID 40S TO LOW 50S WILL BE COMMON ELSEWHERE. ALSO
LOOK FOR FOG TO FORM IN THE NRN RIVER/STREAM VALLEYS TOWARDS DAWN.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
THE HIGH IS EXPECTED TO QUICKLY SLIDE OFF THE EAST COAST MONDAY
SETTING UP A RETURN FLOW OF AIR OUT OF THE SOUTH. SREF/GEFS BOTH
SHOW PWATS OF 1-2 SD ABOVE NORMAL SLIDING BACK INTO WESTERN PA BY
THE END OF THE DAY. SHORT RANGE OPERATIONAL MODELS SHOW THE CHANCE
FOR SHOWERS OVER MY FAR WESTERN ZONES BEFORE NIGHTFALL. SREF AND
GEFS BOTH SHOW SMALL CHANCES FOR RAIN...THE SREF BEING SLIGHTLY
MORE AGGRESSIVE THAN THE GEFS. IT ALL POINTS TO SCATTERED SHOWERS
OR EVEN A THUNDERSTORM BY LATE DAY.
I LEANED TWD A MULTI-MODEL MOS BLEND FOR TOMORROW`S MAX TEMPS
WHICH YIELDS READINGS FROM THE UPPER 60S TO MID 70S FROM NE TO SW.
THIS WILL RANGE FROM NEAR NORMAL OVER THE NORTH TO SEVERAL DEG
COOLER THAN NORMAL OVER THE SOUTHEAST.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
NOT A LOT OF CHANGE FROM YESTERDAY. LOOKING AT A LARGE AREA OF
HIGH PRESSURE BUILDING ACROSS THE REGION...WITH A SLAB OF HOT
AIR FROM THE HIGH SOUTHERN PLAINS MOVING EASTWAFD. WITH AN EML
AIRMASS IN PLACE...AND A TENDENCY TO CAP ANY CONVECTION...THINK
VERY LITTLE CHC OF RAIN WITH WARM FRONT LATE MONDAY NIGHT...AND
NOT MUCH IN THE WARM SECTOR ON WED...MAYBE A FEW STORMS LATE.
DID UP TEMPS SOME AND LOWER POPS A LITTLE.
HIGHEST CHC OF STORMS WILL BE ON THU...AS COLD FRONT NEARS.
COMPLEX FRONT...MORE LIKE 2 COLD FRONTS.
COLDER AIR FOR LATE IN THE WEEK...BUT THIS IS COMPLEX TOO.
EC RUNS HINT AT LESS HIGH PRESSURE MAY BUILD IN...AND UPPER LVL
TROUGH COULD TRY TO CLOSE OFF JUST EAST OF THIS AREA.
AS FAR AS LAKE EFFECT GOES...HARD TO SEE MUCH...PERHAPS SOME
LATER ON FRIDAY...AS COLD AIR DEEPENS...AND WINDS ALOFT BECOME
MORE NW.
THE MAIN STORY WILL BE THE HEAT. MANY SPOTS WILL LIKELY SEE
90 DEGREES...BETWEEN TUE AND LATE THU...AS PLUS 18 DEGREE AIR
OR HIGHER MOVES IN AT 850 MB ON WESTERLY FLOW. NAM STILL THE
WARMEST MODEL.
NOT SURE I BUY INTO THE HIGH DEWPOINTS ON TUE...ETC...WITH THIS
AIRMASS...GIVEN WHERE THE AIRMASS COMES FROM. WHILE THERE WILL BE
POTENTIAL FOR STRONG STORMS AT SOME POINT...THIS WILL LARGELY
DEPEND ON HOW MUCH LOW LVL MOISTURE WORKS INTO THE AREA. ANYWAY...
ENJOY THE LATE SUMMER WEATHER...AS WE MAKE UP FOR WHAT WAS A WET
EARLY SUMMER.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
THE SFC COLD FRONT IS CLEARING MY SERN ZONES AS OF EARLY
AFTERNOON. STILL A BAND OF CLOUDS BEHIND THE FRONT WITH MVFR CIGS
HANGING IN OVER THE AREA FROM JST-AOO NORTHWARD. STILL EXPECTING
DRY AIR TO MIX IN AND ALLOW FOR IMPROVEMENT TO VFR AT ALL SITES BY
MID AFTERNOON.
HIGH PRES WILL MOVE INTO THE AIRSPACE TONIGHT WITH SFC WINDS
SHIFTING FROM NORTH TO ENE-SSE AND BECOMING LIGHT. FOG IS POSSIBLE
OVER THE NRN RIVER VALLEYS LATE TONIGHT UNTIL SHORTLY AFTER
SUNRISE MONDAY UNDER THE CLEAR SKIES AND LIGHT WINDS.
THE FOG WILL LIFT MONDAY MORNING AND ALL SITES WILL BECOME VFR BY
MID MORNING...AND REMAIN SO THROUGHOUT THE DAY. COULD BE A LATE
DAY SHOWER OR THUNDERSTORM OVER WESTERN SXNS.
OUTLOOK...
TUE...AM FOG PSBL. ISOLD PM TSTM IMPACTS PSBL.
WED...SCT PM TSTM IMPACTS PSBL.
THU...SCT-NMRS TSTM IMPACTS PSBL WITH COLD FROPA.
FRI...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD/LA CORTE
SHORT TERM...LA CORTE
LONG TERM...MARTIN
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
942 AM CDT SUN SEP 8 2013
.DISCUSSION...
NO CHANGES TO THE MORNING FORECAST ARE ANTICIPATED.
HAVE BEEN MONITORING MCS NEAR ST. LOUIS...WHICH IS SLOWLY
WEAKENING. THE LATEST HRRR AND 12Z NAM MODEL IS ALSO INDICATING
THIS TREND THROUGH THE EARLY AFTERNOON HOURS...WITH SOME ISOLATED
REDEVELOPMENT ON IT`S SOUTHERN FLANK LATER TODAY ACROSS OUR NORTH.
THUS LATE AFTERNOON AND OVERNIGHT RAIN CHANCES LOOK TO BE ON
TRACK FOR NOW. QUESTION THAT ARISES FOR THE AFTERNOON FORECAST
PACKAGE WILL BE COVERAGE AFTER SUNSET AS THE NAM KEEPS ACTIVITY
GOING THROUGH LATE MONDAY MORNING. IF THIS SCENARIO
UNFOLDS...SEVERAL LOCATIONS ALONG AND NORTH OF INTERSTATE FORTY
COULD RECEIVE A WELCOMED SIGNIFICANT RAINFALL.
HIGH LEVEL MOISTURE FROM COMPLEX WILL CONTINUE TO BUILD SOUTH
INTO OUR AREA OVER THE NEXT 3 TO 6 HOURS...KEEPING HIGHS A FEW
DEGREES BELOW GUIDANCE.
JAB
&&
.PREV DISCUSSION... /ISSUED 630 AM CDT SUN SEP 8 2013/
DISCUSSION... /ISSUED 507 AM CDT SUN SEP 8 2013/
FEW CHANGES TO RECENT FORECASTS. A LARGE AN UNSEASONABLY STRONG
UPPER LEVEL HIGH PRESSURE RIDGE REMAINS THE PRIMARY WEATHER
FEATURE...WHICH WILL RESULT IN DAYTIME TEMPS AVERAGING SEVERAL
CATEGORIES ABOVE EARLY/MID SEPTEMBER CLIMATOLOGICAL NORMALS.
THE UPPER RIDGE WAS CENTERED OVER THE CENTRAL PLAINS EARLY THIS
MORNING...WITH WEAK NORTH/NORTHWEST UPPER LEVEL FLOW OVER THE
MIDSOUTH. GOES WATER VAPOR IMAGERY SHOWED A WEAK SHORTWAVE
EMBEDDED IN THIS NORTHWEST FLOW OVER CENTRAL IL. THIS FEATURE WILL
DROP INTO THE MIDSOUTH BY THIS EVENING... SLOWING ITS PROGRESS
WITH THE APPROACH OF THE UPPER RIDGE CENTER. A FEW THUNDERSTORMS
MAY OCCUR TO THE NORTH AND NORTHEAST OF MEMPHIS THIS AFTERNOON AND
EARLY EVENING...WHERE COOLER MIDLEVEL TEMPS AID IN WEAKENING THE
OTHERWISE ROBUST CINH /CONVECTIVE INHIBITION/.
THE GFS AND NAM DIFFER GREATLY WITH DAYTIME RAIN CHANCES MONDAY
AND TUESDAY. THE NAM CONTINUES TO DEVELOP RATHER ROBUST QPF FIELDS
UNDER THE UPPER RIDGE CENTER...WHILE THE GFS SHOWS MUCH MORE LIMITED
QPF. SOUNDINGS ARE SIMILAR ENOUGH BETWEEN THE TWO MODELS AND
SUSPECT THE DIFFERENCES ARE PRIMARILY DUE TO CONVECTIVE PARAMETRIZATION
IN THE WEAK KINEMATIC ENVIRONMENT UNDER THE ROBUST UPPER RIDGE.
THE DRIER GFS APPEARS TO BE WELL CORROBORATED BY THE ECMWF AND AS
SUCH HAS BEEN USED AS THE BASIS FOR FORECAST POPS.
MIDWEEK PERIODS LOOK TO BE HOT UNDER THE UPPER RIDGE. A DEEP BUT
PROGRESSIVE UPPER TROF WILL DROP INTO THE NORTHEASTERN THIRD OF THE
U.S. ON THURSDAY...BRINGING UPPER LEVEL NORTHWEST FLOW AND ASSOCIATED
SURFACE COLD FRONTAL PASSAGE TO THE MIDSOUTH. THIS FRONT WILL PROVIDE
FOCUS FOR ISOLATED THUNDERSTORM DEVELOPMENT...FOLLOWED BY NOTICEABLY
LOWER DEWPOINTS A SOME RELIEF FROM THE HEAT HEADED INTO THE EARLY
WEEKEND.
THE UPPER LEVEL RIDGE WILL QUICKLY BUILD BACK BY SUNDAY...CENTERED
OVER THE OZARK PLATEAU. THIS RIDGE WILL THEN EXPAND EASTWARD
THROUGH THE MIDDLE OF NEXT WEEK... DOMINATING THE SOUTHEASTERN
THIRD OF THE LOWER 48 BEYOND THE MID SEPTEMBER MARK.
PWB
&&
.AVIATION...
12Z TAF SET
VFR CONDITIONS EXPECTED OVER NEXT 24 HOURS. CLUSTER OF SHRAS/TSRAS
CURRENTLY NORTH OF ST LOUIS WILL PUSH SOUTH TODAY. EXPECT A DYING
BROKEN LINE OF SHRAS TO MOVE ACROSS MO/AR AND KY/TN BORDER AROUND
20Z. WILL MENTION OF VCSH AT KJBR AND KMKL. SHRAS SHOULD DISSIPATE
BY 00Z. REDEVELOPMENT OF SHRAS/TSRAS COULD OCCUR DURING EVENING
INTO OVERNIGHT HOURS AS A SHORTWAVE MOVES TO THE AREA. NOT
CONFIDENT ENOUGH TO MENTION IN TAFS AT THIS POINT. LIGHT SW WINDS
EXPECTED THROUGH THE PERIOD.
KRM
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 94 75 95 74 / 10 10 20 10
MKL 92 67 93 68 / 20 20 10 10
JBR 96 70 96 69 / 20 20 20 10
TUP 94 70 94 69 / 0 10 20 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1140 PM CDT SAT SEP 7 2013
.UPDATE...AREA RADARS SHOWED SOME ISOLATED TO SCATTERED SHOWERS
DROPPING SOUTHWARD ACROSS SOUTHERN ILLINOIS LATE TONIGHT, AND
LATEST HRRR SUGGESTS THAT AT LEAST ISOLATED SHOWERS OR
THUNDERSTORMS COULD MAKE IT DOWN INTO NORTHEASTERN MIDDLE
TENNESSEE TOWARD SUNRISE, AS WEAK COLD FRONT DROPS SOUTHWARD.
THESE ISOLATED SHOWERS AND STORMS MAY VERY WELL PERSIST DURING THE
LATER MORNING HOURS OVER EASTERN AREAS. THUS, HAVE ADDED THE
POSSIBILITY OF ISOLATED SHOWERS AND STORMS TO EASTERN AREAS AFTER 12Z.
HAVE ALSO RAISED DEW POINTS AND MIN TEMP EXPECTATIONS A BIT, BASED
ON LATEST TRENDS AND MOS GUIDANCE.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
19
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
155 PM CDT SUN SEP 8 2013
.UPDATE...
Adjusted POPS and temperatures for the remainder of the afternoon
hours.
&&
.DISCUSSION...
Isolated to widely scattered showers are developing across southern
sections early this afternoon. Based on latest observational trends
and recent HRRR data, should see a bit better coverage across
southern sections. POPS were increased slightly across the Northern
Edwards Plateau and Northwest Hill Country counties where scattered
convection is expected. Also increased cloud cover across southern
sections and decreased max temps a couple of degrees based on
current trends. Highs should top out in the upper 80s along the
I-10 corridor to the mid and upper 90s across the Big
Country.
&&
.PREV DISCUSSION... /ISSUED 1230 PM CDT SUN SEP 8 2013/
DISCUSSION...
See 18Z aviation discussion below.
AVIATION...
Isolated to widely scattered convection will be possible across
the southern terminals this afternoon. Thunder should be limited
but did include VCSH at both the KJCT and KSOA terminals after 20Z.
Brief MVFR conditions possible with any of the showers and will
amend as necessary based on convective trends. Stratus returns to
the southern terminals after 09Z Monday with MVFR conditions
expected at KJCT, KSOA and KBBD through mid/late morning hours.
PREV DISCUSSION... /ISSUED 621 AM CDT SUN SEP 8 2013/
DISCUSSION...
See 12Z aviation discussion below.
AVIATION...
Scattered areas of low level stratus are moving north across mainly
the Northern Edwards Plateau and Northwest Hill Country. Will keep
the southern terminals VFR and keep an eye low cloud trends the next
few hours for possible amendments. Otherwise, expect VFR conditions
the next 24 hours. Isolated showers and thunderstorms will be
possible this afternoon across the southern 1/3, mainly south of a
San Angelo to Brownwood line. Will not include in the TAFS due to
very limited coverage.
21
PREV DISCUSSION... /ISSUED 338 AM CDT SUN SEP 8 2013/
SHORT TERM...
/Today and Tonight/
An upper level high was over the Central Plains this morning,
with upper level easterly flow over West Central Texas. At the
surface, low level moisture was increasing across the area with
dewpoints in the 60s. Mild temperatures prevailed with readings
in the 70s.
The upper level high will still have an influence across West
Central Texas today. However, the combination of the upper level
easterly flow and some instability will lead to the possibility of
isolated afternoon and early evening showers and thunderstorms
across southern areas, mainly south of a San Angelo to Brownwood
line. The thunderstorms will have the potential to produce
dangerous lightning and gusty winds. Highs will be in the 90s. The
warmest readings/upper 90s/ will be across the Northern Big
Country a little closer to the 850 MB thermal ridge.
Isolated convection will dissipate by 02Z Monday. Otherwise for
tonight, expect mostly clear skies with lows mainly in the lower
70s.
21
LONG TERM...
/Monday through Saturday/
Continued warm, with possible isolated afternoon showers and
thunderstorms through Tuesday.
By Monday...the upper level ridge currently centered in the
Central Plains will be in the process of re-centering over the
southeastern U. S. The result in our area will be deep, moist,
southeasterly flow from Monday into the mid week. Thus, we could
see continue to see isolated showers and thunderstorms,
especially across our southern counties that will have better low
level moisture to work with. So, will go ahead with isolated
thunderstorm wording for areas mainly south of a Barnhart to San
Saba line for Monday afternoon, and a slight chance on Tuesday
afternoon for roughly the same area. With the high sliding off to
the east, and better moisture moving into the area, we could see
some slight relief from the hot temperatures, and have cooler our
highs through the next several days a few degrees. However, we
will still remain a few degrees above normal through the end of
the forecast period.
Beyond Tuesday, kept the forecast dry for now. The GFS shows a
distinct upper low moving across our southern counties Thursday.
However the EC is much weaker with the same feature, and the GFS
has been inconsistent as far as path and timing for the same
feature, so it`s hard to trust it wholly at this point.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 95 70 93 69 91 / 10 5 5 5 5
San Angelo 93 70 91 69 91 / 20 10 10 5 20
Junction 89 71 89 67 89 / 30 20 10 10 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
1010 PM MST MON SEP 9 2013
...ELEVATED PRECIPITATION CHANCES WITH HEAVY RAINFALL POTENTIAL
CONTINUES TONIGHT AND TUESDAY...
.SYNOPSIS...
AN UPPER LOW WILL CONTINUE TO PROVIDE WEATHER DISTURBANCES TO
INTERACT WITH MONSOON MOISTURE...SUPPORTING A CONTINUED WET AND
ACTIVE STORM PATTERN WITH THE THREAT FOR HEAVY RAINFALL. CLOUDY
SKIES IN COMBINATION WITH SHOWERS AND THUNDERSTORMS WILL KEEP
DAYTIME HIGHS WELL BELOW NORMAL THROUGH MIDWEEK. MOISTURE WILL BE
SLOW TO CLEAR OUT OF THE AREA...KEEPING AT LEAST SLIGHT CHANCES IN
THE FORECAST THROUGH THE END OF THE WORK WEEK. TEMPERATURES WILL
ALSO BEGIN A SLOW CLIMB BACK TOWARDS MORE NORMAL READINGS.
&&
.DISCUSSION...
STORM ACTIVITY APPEARS TO BE WINDING DOWN FOR THE EVENING OVER OUR
FORECAST AREA THOUGH THERE ARE LINGERING SHOWERS AND ISOLATED
THUNDERSTORMS OVER SOUTHWEST ARIZONA AND FAR SOUTHEAST CALIFORNIA AS
OF THIS WRITING. THIS IS WHERE THE MAJORITY OF THE ACTION WAS FROM
ROUGHLY MID AFTERNOON ONWARD. TODAY AND YESTERDAY VORT MAXES FROM
MEXICO HAVE BEEN PULLED NORTHWARD INTO ARIZONA LEADING TO ANOMALOUS
EARLY DAY PRECIPITATION OVER SOUTH-CENTRAL ARIZONA. SATELLITE
IMAGERY SHOWS MAIN UPPER LOW REMAINS CENTERED OVER SOUTHEAST
CALIFORNIA. THIS LOW AND AND SUFFICIENT SURFACE HEATING HELPED MAKE
THINGS ACTIVE OVER SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA. THE
LATEST RUC SUGGESTS ANOTHER VORT MAX FROM NORTHERN MEXICO WILL MOVE
INTO SOUTH-CENTRAL ARIZONA OVERNIGHT BUT IT ONLY GENERATES PRECIP
OVER OUR HIGHER TERRAIN ZONE EAST OF THE PHOENIX AREA. IT ALSO SHOWS
A VORT LOBE ROTATING AROUND THE MAIN LOW CENTER AFFECTING SOUTHWEST
ARIZONA. THE GFS AND NAM HAVE VARIATIONS ON THAT SAME THEME WITH THE
NAM SHOWING WEAKER VORTICITY FEATURES. THE LATEST HRRR MODEL
SUPPORTS THE RUC SCENARIO BUT ALSO HAS SPOTTY PRECIP ELSEWHERE
THROUGH THE MORNING HOURS INCLUDING THE PHOENIX AREA. HOWEVER...IT
HAS BEEN OVERDOING THE PRECIP IN WESTERN PORTIONS OF OUR FORECAST.
GIVEN THE GENERAL AGREEMENT ON FURTHER PRECIP POTENTIAL...WILL HOLD
ON TO THE HIGH POPS. OF NOTE...THE PRECIPITABLE WATER HAS BEEN
COMING DOWN PER GPS DATA AND BLENDED SATELLITE IMAGERY...THOUGH THE
LATTER IS A BIT UNDERDONE IN SOME SPOTS. THIS MAY KEEP SUBSEQUENT
DISTURBANCES FROM BEING QUITE AS PRODIGIOUS IN RAIN PRODUCTION.
REGARDING KIWA RADAR DATA OUTAGE...TELEPHONE COMPANY HAS BEEN
WORKING ON REPAIRING DATA CONNECTION AND WE MAY JUST NOW BE GETTING
DATA RESTORED.
&&
.PREVIOUS DISCUSSION ISSUED 304 PM...
INGREDIENTS CAME TOGETHER TODAY AT THE RIGHT TIME TO SUPPORT EARLY
MORNING SHOWER ACTIVITY THAT DEVELOPED INTO LARGER AND HEAVIER
THUNDERSHOWER ACTIVITY ACROSS MUCH OF CENTRAL ARIZONA. DEEP PLUME OF
TROPICAL MOISTURE OVERSPREADING THE REGION...WITH PWATS PUSHING 2
INCHES EARLIER IN THE DAY...WITH BLENDED TPW CURRENTLY SHOWING 1.75
INCH AMOUNTS ACROSS CENTRAL ARIZONA. CUT-OFF UPPER TROUGH/LOW TO OUR
WEST CONTINUED A SLOW EASTWARD PROGRESSION THROUGH THE DAY...ADDING
FAVORABLE CYCLONIC SPIN ACROSS THE AREA. COUPLE THAT WITH ADDITIONAL
EMBEDDED SHORTWAVES/IMPULSES AROUND THE RIDGE FLOW TO OUR EAST
OCCURRING DURING THE MIDDAY HOURS...AND WIDESPREAD SHOWER AND STORM
DEVELOPMENT ENSUED.
SCATTERED STORM ACTIVITY CONTINUES ACROSS WESTERN ARIZONA AND TO A
MORE ISOLATED EFFECT ACROSS SOUTHEAST CALIFORNIA...WHERE SKIES WERE
CLEAR FOR MUCH OF THE DAY. RADAR LOOP OF THE REGION SHOWS THE BROAD
UPPER LOW CIRCULATION JUST REACHING THE COLORADO RIVER VALLEY AND
THAT WILL AID IN FURTHER SHOWER AND STORM DEVELOPMENT THROUGH THE
EVENING. WITH THE AMOUNT OF TROPICAL MOISTURE AVAILABLE...EXPECT
EVEN SMALL SHOWERS TO HAVE HEAVY RAINFALL POTENTIAL. EVEN WITH THE
EARLIER SHOWER ACTIVITY WITH THE BROAD SCALE DYNAMICS AND CONTINUED
MOISTURE PRESENCE...UNSETTLED SHOWERY AND THUNDERSHOWER CONDITIONS
WILL PERSIST EVEN BACK INTO CENTRAL ARIZONA TONIGHT. CONDITIONS COULD
BE COME UNSTABLE ENOUGH ACROSS CENTRAL ARIZONA NOW THAT CONDITIONS
HAVE CLEAR TO SEE STORMS ACROSS WESTERN ARIZONA MOVE INTO THE PHOENIX
AREA AGAIN...PRODUCING ADDITIONAL HEAVY RAINFALL THROUGHOUT THE
EVENING.
MAINTAINED LIKELY SHOWER MENTION WITH CONTINUED ISOLATED THUNDER
THROUGH LATE EVENING...WITH THUNDERSHOWER CHANCES INTO EARLY TUESDAY
MORNING FOR MUCH OF THE FORECAST AREA. FOR TUESDAY...VERY SIMILAR
SET-UP...WITH THE CONTINUAL PRESENCE OF THE UPPER LOW/TROUGH
STALLING OUT NEAR THE COLORADO RIVER AND ADDITIONAL SPOKES OF
SHORTWAVE ENERGY MOVING THROUGH THE REGION. FORECAST MODEL SOUNDINGS
STILL HOLD ON TO AT LEAST 1.5 TO 1.7 INCHES PWAT THROUGH TUESDAY
EVENING. AM INCLINED TO WEIGHT THE FORECAST CLOSER TO THE NAM12 AND
NAMDNG5 FORECASTS...WHO HAVE BEEN THE BEST PERFORMERS IN TERMS OF
TEMPERATURE GUIDANCE AND CONVECTIVE/PRECIPITATION PLACEMENT RECENTLY.
ANOTHER BELOW NORMAL DAY EXPECTED WITH TEMPERATURES FORECAST AREA
WIDE...WITH THE WESTERN DESERTS OF IMPERIAL COUNTY AND FAR WESTERN
ARIZONA SEEING THE BEST CHANCES FOR CLEAR ENOUGH TO SKIES TO WARM
INTO THE 90S TUESDAY.
MINOR DETAILS FROM THE GUIDANCE WILL BE VERY HARD TO RESOLVE OVER
THE NEXT FEW DAYS...SUCH AS THE LITTLE DISTURBANCES/VORT MAXES MOVING
THROUGH THE FLOW. HOWEVER...BASIC FORECAST IDEA IS HANDLED FAIRLY
WELL AND THE PROGS CONTINUE TO ADVERTISE THE UPPER LOW TO MORE OR
LESS REMAIN IN PLACE THROUGH TUESDAY NIGHT. A SERIES OF VORT SPOKES
WILL ROTATE AROUND THE LOW...AND ADDITIONAL VORT MAXES WILL MOVE
NORTH OUT OF MEXICO...AND THESE FEATURES WILL ACT ON A VERY MOIST AND
RATHER UNSTABLE AIRMASS TO PRODUCE SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS. UNLIKE A MORE NORMAL MONSOONAL PATTERN THE
SHOWERS/STORMS WILL BE ABLE TO OCCUR AT ANY TIME...NOT THE FAVORED
LATE AFTERNOON AND EVENING TIMES DURING A TYPICAL MONSOON DAY.
THUS...POPS WILL BE VERY HIGH AND BROAD BRUSHED THROUGH TUESDAY
NIGHT...WITH GOOD CHANCE TO LIKELY NUMBERS ACROSS MOST OF THE CWA
EACH PERIOD. GIVEN THE HIGH MOISTURE CONTENT THE PRIMARY WEATHER
THREAT WILL BE LOCALLY HEAVY RAIN WHICH COULD LEAD TO SOME FLOODING
OR FLASH FLOODING. OF COURSE GUSTY WINDS ARE POSSIBLE...SUCH AS SEEN
IN A WET MICROBURST...BUT HEAVY RAIN IS A MORE LIKELY OCCURRENCE. MAX
TEMPS ARE FORECAST TO RUN WELL BELOW SEASONAL NORMALS TODAY AND
TUESDAY...ESPECIALLY OVER SOUTH CENTRAL AZ WHERE HIGHS BOTH DAYS WILL
STRUGGLE TO REACH INTO THE LOW OR MID 90S.
BY WEDNESDAY THE LOW TO OUR WEST IS FORECAST TO MIGRATE NORTHWARD
INTO NORTHERN AZ OR SOUTHERN NEVADA/UTAH. AS THIS OCCURS STEERING
FLOW BECOMES SOUTHWEST TO WEST AND THIS WILL LEAD TO A GRADUAL
EROSION OF MOISTURE AND A DECREASE IN OUR POP TRENDS. BY WED EVENING
POPS WILL LOWER TO MOSTLY LESS THAN 25 PERCENT EXCEPT FOR HIGHER
TERRAIN AREAS EAST OF PHOENIX. HIGH TEMPS WILL STILL BE SUPPRESSED
AS MOISTURE WILL STILL BE SOMEWHAT ON THE HIGH SIDE. FOR THURSDAY
INTO THE WEEKEND...THE PERSISTENT WEST OR NORTHWEST STEERING FLOW
WILL CONTINUE TO ERODE MOISTURE...AND POPS WILL LOWER INTO THE
SINGLE DIGITS OVER THE WESTERN DESERTS...WITH ONLY SLIGHT CHANCES
LEFT OVER SOUTH CENTRAL ARIZONA. IN FACT...BY THE WEEKEND STORMS
SHOULD BE MOSTLY CONFINED TO HIGHER TERRAIN LOCATIONS SOUTHEAST AND
EAST OF THE GREATER PHOENIX AREA...WITH MOSTLY SUNNY SKIES EXPECTED
ACROSS THE CENTRAL AND WESTERN DESERTS. OF COURSE THERE WILL BE A
WARMING TREND AS THE MOISTURE THINS...WITH TRIPLE DIGIT HIGHS
FORECAST OVER MOST OF THE LOWER DESERTS BY THURSDAY. HIGHS SHOULD
REACH BACK TO SEASONAL NORMALS ACROSS THE CENTRAL AZ DESERTS BY THE
WEEKEND.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
ANTICIPATE QUIET CONDITIONS THROUGH 07Z BEFORE ANOTHER DISTURBANCE
BEGINS TO BRING SHOWERS AND ISOLATED THUNDERSTORMS TO SOUTH-CENTRAL
ARIZONA. HOWEVER...MAIN AREA OF ACTIVITY EXPECTED TO BE FOCUSED MORE
OVER THE HIGHER TERRAIN JUST EAST OF THE METRO AREA. MOISTURE
AVAILABILITY NOT AS GOOD AS MONDAY MORNING WAS AND THUS NOT
EXPECTING A REPEAT. HOWEVER...FOCUS AREA COULD EASILY WIND UP OVER
PHOENIX AREA. FOR NOW...WILL HOLD ON TO VCSH IN TAFS. MAIN WINDOW
FOR PRECIP/CEILING POTENTIAL WILL BE PRIOR TO 20Z TUESDAY.
ANTICIPATE LIGHT AND VARIABLE WINDS.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE
OVERNIGHT DUE TO A LINGERING UPPER LOW CENTERED OVER THE AREA. WILL
HOLD ON TO VCSH IN TAFS. SOME AFTERNOON REDEVELOPMENT OF TSTMS IS
POSSIBLE BUT CONFIDENCE TOO LOW TO REFLECT IN TAFS. OTHERWISE
ANTICIPATE LIGHT AND VARIABLE WINDS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
DRIER AND WARMER CONDITIONS WILL PREVAIL THIS PERIOD. LIGHT WIND.
ISOLATED AFTERNOON AND EVENING TSTMS POSSIBLE HIGHER TERRAIN OF
SOUTHERN GILA COUNTY. MINIMUM RELATIVE HUMIDITIES WILL GENERALLY
FALL INTO THE TEENS ON THE DESERTS...AND NEAR 30 PERCENT IN THE
HIGHER TERRAIN OF SOUTHERN GILA COUNTY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ
PREVIOUS DISCUSSION...NOLTE/CB
AVIATION....AJ
FIRE WEATHER...VASQUEZ
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
307 AM MDT TUE SEP 10 2013
.SHORT TERM...AN UPPER LEVEL LOW WILL REMAIN OVER THE SWRN US AS
DISTURBANCES EMBEDDED IN THE FLOW OF SUBTROPICAL MOISTURE MOVE
NNE ACROSS COLORADO. ONE WELL DEFINED FEATURE IS ALREADY MOVING
NORTHWARD OVER WRN CO EARLY THIS MORNING AND IS HELPING MAINTAIN
SHOWER ACTIVITY IN THE MTNS AND ALONG AND NR THE FOOTHILLS. AS
THIS FEATURE CONTINUES TO LIFT NORTH WOULD EXPECT SHOWER ACTIVITY
TO DECREASE BY MID MORNING IN MOST AREAS.
FOR THIS AFTN THERE IS A 2ND FEATURE CURRENTLY NOW ALONG THE ENCTRL
AZ-WCNTRL NM BORDER WHICH IS MOVING NNE AS WELL. AS THIS FEATURE
LIFTS NNE INTO SWRN CO BY AFTN WOULD EXPECT SHOWERS AND TSTMS
TO INCREASE IN THE MTNS. EAST OF THE MTNS NOT SURE HOW THINGS ARE
GOING TO EVOLVE THIS AFTN. THE LATST HRRR DEVELOPS A WEAK CYCLONE
OVER SRN DOUGLAS COUNTY THIS AFTN WITH MAINLY ELY LOW LVL FLOW
OVER NERN CO. THE HRRR WARMS HIGHS INTO THE MID TO UPPER 70S OVER
THE PALMER DIVIDE WHILE FURTHER NORTH READINGS ARE ONLY IN THE
UPPER 60S TO NEAR 70 FM NORTH OF DENVER TO THE WY BORDER. IF THIS
ENDS UP BEING CORRECT THEN THE BEST CHC OF STRONGER STORMS WOULD
BE FM THE SRN FOOTHILLS ACROSS THE PALMER DIVIDE WHILE ACTIVITY
FURTHER NORTH WOULD NOT BE AS STG AND LESS WIDESPREAD. SO WILL
KEEP THE HIGHEST POPS FM DENVER SOUTH TO THE PALMER DIVIDE TOWARDS
LIMON. WITH PRECIPITABLE WATER VALUES RANGING FM 1.10 TO 1.20
INCHES THE STRONGER STORMS COULD EASILY PRODUCE UP TO 2 INCHES OF
RAIN IN LESS THAN AN HOUR. MEANWHILE OVER THE NERN PLAINS TEMPS
LOOK LIKE THEY WILL BE IN THE UPPER 70S TO LOWER 80S WITH TSTM
COVERAGE NOT AS GREAT.
FOR TONIGHT THE DISTURBANCE OVER SWRN CO WILL PROBABLY MOVE NNE
ACROSS THE MTNS AS SHOWN BY THE LATEST ECMWF. AS A RESULT THERE
WILL BE ADDITIONAL SHOWERS AND A FEW TSTMS IN THE MTNS WITH SOME OF
THIS ACTIVITY SPREADING ACROSS THE FOOTHILLS AND PORTIONS OF THE
URBAN CORRIDOR OVERNIGHT.
.LONG TERM...MODELS CONTINUE TO INDICATE A DEEP...ANOMALOUSLY
MOIST SUBTROPICAL FLOW OVER NEW MEXICO...COLORADO AND THE WESTERN
GREAT PLAINS WEDNESDAY AND THURSDAY. MEAN LAYER PRECIPITABLE WATER
VALUES QUITE IMPRESSIVE FOR THIS TIME OF YEAR OVER EASTERN
COLORADO. VALUES MORE OFTEN OBSERVED IN JULY-EARLY AUGUST. FOR
INSTANCE...THE NAM...GFS...WRF AND SREF INDICATE PW VALUES UP
AROUND 1.25 INCHES ALONG THE FRONT RANGE FOOTHILLS WEDNESDAY
AFTERNOON. GFS STAYS JUST AS MOIST WEDNESDAY NIGHT AND
THURSDAY...WHILE THE NAM AND SREF INDICATE SOME DRYING ON
THURSDAY...BUT PW VALUES STILL ABOVE THE CLIMATOLOGICAL NORM. THIS
MOIST SOUTHERLY FLOW IS DRIVEN BY A NEARLY VERTICALLY STACKED
CYCLONE CENTERED NEAR LAS VEGAS ON WEDNESDAY. MODELS SHOW LITTLE
MOVEMENT IN THIS FEATURE THROUGH WEDNESDAY NIGHT. DIVERGENT FLOW
ALOFT EAST OF THE LOW OVER COLORADO IS PROGGED TO STRENGTHEN SOME
ON THURSDAY AS THE CYCLONE BEGINS ITS SLOW NORTHWARD MIGRATION.
STRONGEST UPWARD QUASI-GEOSTROPHIC VERTICAL VELOCITIES WEDNESDAY/
THURSDAY OVER EASTERN UTAH AND WESTERN COLORADO...WITH WEAK
RISING MOTIONS OVER EASTERN COLORADO. BY FRIDAY...MODELS SHOW THE
MEAN UPPER LOW OVER NRN UTAH/SERN IDAHO AND A SOUTHWESTERLY FLOW
OVER COLORADO. THIS WILL LOWER PW AND SPECIFIC HUMIDITY VALUES
ACROSS THE FORECAST AREA ON SATURDAY...PARTICULARLY IN THE HIGH
COUNTRY AS THE CLOSED UPPER CYCLONE OPENS UP INTO A TROUGH AND
SWINGS EAST OVER MONTANA AND WYOMING. BY SUNDAY ECMWF AND GFS
SHOW THE TROUGH PASSING OVER THE DAKOTAS ON SUNDAY...WITH THE
TAIL END OF THIS TROUGH AND WHAT APPEARS TO BE A COLD FRONT
BRUSHING NORTHEAST COLORADO. THIS WILL COOL TEMPERATURES BY AT
LEAST A FEW DEGS AND GIVE THE AREA ANOTHER CHANCE OF SHOWERS.
THEREFORE...WILL HANG ONTO THE HIGH POPS ON WEDNESDAY AND
THURSDAY...AND WITH THE WETBULB ZERO LOWERING LATE WEDNESDAY AND
THURSDAY...COULD SEE A SOME SNOW ACCUMULATION ON THE HIGHER PEAKS.
INSTABILITY WILL BE LIMITED DUE TO A HEAVY CLOUD COVER AND COOLER
TEMPERATURES. THIS WILL LIMIT THUNDERSTORM DEVELOPMENT AND THE
CHANCE OF HEAVY RAINFALL. SFC TEMPERATURES ARE LIKELY TO BE WELL
BELOW AVERAGE THROUGH AT LEAST THURSDAY NIGHT. LATEST NAM AND GFS
TEMPERATURE GUIDANCE FOR BOTH DAYS NOW LOOKS SLIGHTLY COOLER THAN
EARLIER GUIDANCE INDICATED. ECMWF TEMP GUIDANCE IS NOT AS COOL.
FCST HIGH TEMPERATURES BOTH DAYS IN THE 60S AT LOWER ELEVATIONS
AND 40S TO AROUND 60 IN THE HIGH COUNTRY. AT ANY RATE...IT`LL
DEFINITELY FEEL FALL-LIKE AFTER THE RECORD/NEAR RECORD HEAT OF THE
PAST COUPLE WEEKS. CONDITIONS SHOULD BEGIN TO WARM AND DRY OUT
FROM WEST TO EAST...SLOWLY AT FIRST...ON FRIDAY AND SATURDAY.
SHOULD SEE A MOVE AWAY FROM UPSLOPE TYPE STRATIFORM PRECIP TO
CONVECTIVE PRECIP/T-STORM ACTIVITY ON SATURDAY WITH THE LIFT
GENERATED BY THE TROUGH PASSING TO OUR NORTH AND WITH MORE SOLAR
HEATING. TEMPERATURES SHOULD BE NEAR AVERAGE ON SATURDAY. THEN A
DIP IN TEMPERATURE AND ANOTHER CHANCE OF SHOWERS ON SUNDAY WITH
THE PASSAGE OF THE COLD FRONT REFERRED TO ABOVE. BY MONDAY...
MODELS SHOW A RETURN TO DRIER AND WARMER CONDITIONS WITH WEST-
NORTHWESTERLY FLOW ALOFT AND DOWNSLOPE FLOW DOWN LOW.
&&
.AVIATION...A FEW SHOWERS MAY AFFECT THE AREA EARLY THIS MORNING
WITH BRIEF MVFR CONDITIONS POSSIBLE. WITH 5000-6000 FOOT CEILINGS
AROUND NOT SURE IF IFR CONDITIONS ARE GOING TO DVLP BUT AM NOT
CONFIDENT ENOUGH TO TOTALLY YANK THEM OUT AT THIS POINT.
FOR THIS AFTN SFC WINDS SHOULD BE MAINLY ELY. AS TALKED ABOUT ABV
BEST CHC OF STRONGER STORMS LOOKS TO BE FM DENVER SOUTH TO THE
PALMER DIVIDE WITH ACTIVITY DEVELOPING BY 20Z-21Z. DIA MAY END UP
BEING ON THE NRN FRINGE OF THE STRONGER ACTIVITY. HOWEVER IF A
STRONGER STORM WERE TO MOVE ACROSS THEN MVFR CONDITIONS COULD
BRIEFLY OCCUR.
BY TONIGHT INITIAL BATCH OF SHOWERS AND TSTMS WILL PROBABLY DIMINISH
BY 01Z HOWEVER SOME ADDITIONAL SHOWERS AND POSSIBLY A TSTM COULD
REDEVELOP AFTER MIDNIGHT AS A 2ND DISTURBANCE MOVES ACROSS. ONCE
AGAIN THERE COULD BE SOME POTENTIAL FOR STRATUS AND FOG BY 12Z WED
IF SKIES CLEAR LATE.
&&
.HYDROLOGY...SHOWERS AND THUNDERSTORMS WILL INCREASE BY EARLY
AFTERNOON IN THE MOUNTAINS...FOOTHILLS AND ALONG THE FRONT RANGE.
AT THIS TIME IT APPEARS THE STRONGEST STORMS WILL FOCUS FROM
DENVER SOUTHWARD ACROSS THE PALMER DIVIDE INTO THE SOUTHERN
FOOTHILLS. RAINFALL AMOUNTS OF 1 TO 2 INCHES WILL BE POSSIBLE WITH
THE STRONGER STORMS IN LESS THAN 45 MINUTES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER
LONG TERM....RPK
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1111 PM MDT MON SEP 9 2013
.UPDATE...
ISSUED AT 907 PM MDT MON SEP 9 2013
IN THE SHORT TERM...ONE FEATURE STANDS OUT AND THAT IS THE MASS OF
HIGH CLOUD TOPS OVER SE UTAH AND SW COLORADO. LATEST SATELLITE
IMAGERY SHOW WARMING CLOUD TOPS...BUT CONVECTIVE CELLS STILL
CAPABLE OF GENERATING HEAVY SHOWERS WITH CORTEZ ASOS PICKING UP
FOUR TENTHS OF AN INCH IN A SHORT PERIOD OF TIME. THE HRRR SHOW
A BROAD AREA OF ONE HALF TO ONE INCH OF RAIN COVERING SW COLORADO
AND PORTIONS OF SE UTAH BY SUNRISE TUESDAY MORNING. THIS COULD BE
PROBLEMATIC AS SOILS MAY BECOME SATURATED WITH ENHANCED FLOWS IN
DRAINAGES OR NORMALLY DRY WASHES. THE ANTECEDENT CONDITIONS SETS
THE STAGE FOR WHAT IS EXPECTED ON TUESDAY.
TUESDAY...MODEL DATA SHOW A STRONG WAVE LIFTING NORTHWARD ACROSS
THE WESTERN SLOPE. THIS WAVE ENTERS SOUTHWEST COLORADO DURING THE
MORNING HOURS AND MOVES NORTHWARD DURING THE DAY...DEPARTING
NORTHWEST COLORADO LATE TUESDAY NIGHT. ASSOCIATED WITH THIS WAVE
IS DEEP LAYERED MOISTURE TRANSPORT...ISENTROPIC UPGLIDE...AND EVEN
SOME DYNAMICAL FORCING AS WELL TO ENHANCE LIFT. SPEED MAXIMA OF
50 KTS AT 300 MB WILL CREATE AN AREA OF UPPER LEVEL DIVERGENCE.
COMBINED WITH LOW LEVEL CONVERGENCE ASSOCIATED WITH THE BROAD AREA
OF SURFACE LOW PRESSURE...THE NET RESULT WILL BE DEEP CONVECTIVE
TOWERS WHERE CLOUD TOPS MAY BECOME COLDER THAN -60C.
RAINFALL AMOUNTS COULD EXCEED THOSE ON MONDAY...AND WITH SOILS AND
DRAINAGE AREAS BECOMING SATURATED (IF NOT ALREADY)...ADDITIONAL FLASH
FLOODING COULD RESULT. EXPANDED THE AREA OF POTENTIAL FLASH FLOODING
TO COVER THE REST OF THE WESTERN SLOPE THAT WAS NOT COVERED BY THE
WATCH EARLIER.
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 400 PM MDT MON SEP 9 2013
EXCEPTIONALLY WET PERIOD CONTINUES WITH WIDESPREAD PRECIPITATION
OCCURRING ACROSS BOTH CO AND UT WITH THIS TREND CONTINUING. WATER
VAPOR IMAGERY CURRENTLY SHOWING ANOMALOUS AMOUNTS OF MOISTURE
STREAMING UP FROM THE SOUTH WHILE A DEFORMATION AXIS HAS SET UP
OVER NEVADA INTO NRN UTAH. THIS AXIS IS ALLOWING MOISTURE AND
IMPULSES TO CONTINUE STREAMING INTO OUR AREA. LATEST GUIDANCE TO
INCLUDE THE NAM...RAP AND HRRR SHOW PRECIP CONTINUING THROUGH
TONIGHT AND THEN A RELATIVE LULL BEFORE ANOTHER WAVE CAUSES PRECIP
AGAIN DURING THE MORNING HOURS TOMORROW. WITH PLENTY OF RAIN
HAVING ALREADY FALLEN AND MORE ON THE WAY...EXTENDED THE FLASH
FLOOD WATCH THROUGH TUESDAY NIGHT AND ALSO ADDED THE UNCOMPAGHRE
AND ROAN/TAVAPUTS PLATEAUS SINCE THEY SAW THE BULK OF PRECIP
TODAY. SO FAR ONLY A FEW AREAS (PORTIONS OF ARCHES AND CANYONLANDS
NATIONAL PARK) HAVE REPORTED FLOODING DUE TO THE MAINLY STRATIFORM
NATURE OF THE PRECIP THOUGH A FEW EMBEDDED STORMS HAVE FIRED THIS
AFTERNOON. THE BIGGEST CONCERN HAS BEEN...AND CONTINUES TO
BE...SERN UTAH DUE TO THE SLOT CANYON AND DESERT TERRAIN. LOTS OF
CLOUDS HAVE INHIBITED CONVECTION SO FAR TODAY THOUGH VIS IMAGERY
DOES SHOW SOME BREAKS STARTING TO FORM. WILL ALERT NEXT SHIFTS TO
KEEP AN EYE ON AREA. MOST TEMPS ARE RUNNING ABOUT 5 TO 10 DEGREES
COOLER THAN NORMAL DUE TO RAINFALL AND CLOUDS.
OVERNIGHT...SOME MODELS DEPICT MORE STEADY PRECIP TO
CONTINUE...ESPECIALLY FOR THE ABAJOS...LA SALS AND
UNCOMPAGHRE/ROAN/TAVAPUTS PLATEAUS. OTHER MODELS SHOW MORE OF A
LULL. KEPT PRECIP IN FORECAST AS MOISTURE WILL CONTINUE TO STREAM
OVERHEAD AND ANY WEAK DISTURBANCE/IMPULSE WILL CREATE SHOWERS. FOR
TOMORROW THOUGH...MORE IMPULSES WILL CONTINUE TO MOVE OVER THE CWA
WITH WHAT APPEARS TO BE A SIGNIFICANT IMPULSE MOVING INTO THE 4
CORNERS BY 7AM AND THEN SPREADING NWRD BY NOON. FOR TUESDAY
THEN...ANOTHER DAY LIKE TODAY...CLOUDS...RAIN...COOL TEMPERATURES
WITH INCREASED FLOODING CONCERNS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 400 PM MDT MON SEP 9 2013
THE MAIN STORM TRACK WITH THE STRONGER WESTERLIES WILL REMAIN WELL
TO THE NORTH OF THE INTERMOUNTAIN WEST THROUGH THIS EXTENDED PERIOD.
BY WEDNESDAY STRONG TROUGHING INTO THE GREAT LAKES REGION AND INTO
THE GULF OF ALASKA LEAVES AN AMPLIFIED RIDGE OVER THE NORTHERN US
AND CANADIAN ROCKIES. THIS NORTHERN RIDGE WILL LEAD TO A REX PATTERN
DUE TO AN AREA OF LOW PRESSURE THAT GETS CUT OFF....AND WILL WOBBLE
AROUND THE GREAT BASIN. THIS LOW WILL BE HELD FROM MOVING WEST TO
EAST BY THE SUBTROPICAL HIGH OVER THE SOUTHEAST STATES AND PACIFIC
HIGH PRESSURE BUILDING TOWARD THE WEST COAST. THIS PATTERN WILL BE
STATIC THROUGH AT LEAST THURSDAY AFTER WHICH MEDIUM RANGE MODELS
SWING SOME STRONGER ENERGY INTO WESTERN CANADA...BREAKING THE REX
BLOCK...AND ALLOWING THE GREAT BASIN LOW TO TO BEGIN TO LIFT
NORTHWARD. HOWEVER THERE ARE MODEL CONFLICTS WITH HOW THIS LOW
INTERACTS WITH THE ENERGY BREAKING DOWN THE RIDGE BY LATE IN THE
FORECAST...LEAVING VERY LOW CONFIDENCE IN THE LATTER PERIODS SO
BLENDED MODELS GENERALLY FOLLOWED.
SO TO FOCUS ON THE PERIOD WHEN THE UPPER LOW IS CUTOFF IN THE GREAT
BASIN WEDNESDAY AND THURSDAY. THE MODELS ARE SIMILAR IN LIFTING ONE
LOBE OF STRONGER ENERGY NORTHWARD OUT OF OUR CWA ON
WEDNESDAY...WHILE ROTATING ANOTHER STRONG PIECE ACROSS UTAH ON
THURSDAY. SUBSIDENCE BEHIND THE FIRST WAVE WILL GENERALLY BRING
SOMEWHAT OF A DOWNTURN TO THE PRECIPITATION FOR WEDNESDAY...WITH THE
FAMILIAR PATTERN OF STORMS FOCUSING ON THE TERRAIN BY EARLY
AFTERNOON BEFORE SPREADING INTO THE VALLEYS. ASCENT WILL BEGIN TO
INCREASE SIGNIFICANTLY ON THURSDAY AFTERNOON OVER OUR CWA THURSDAY
WITH THE DYNAMIC TROP DIPPING DOWN TOWARD 400MB WHICH SHOULD ENHANCE
THE INSTABILITY AND BRING AN UPTURN TO STORMS FOR THURSDAY. THE
STRONGER MONSOON PLUME WILL GET DISRUPTED BUT STILL PLENTY OF
MOISTURE AROUND FOR MAKING STORMS. THE DRY CONVEYOR BELT ASSOCIATED
WITH THE PV LOBE MAY ALSO LEAD TO SOME STRONGER STORM DEVELOPMENT.
FROM FRIDAY ONWARD THE LOW WILL HAVE LIFTED NORTH AND EAST OF OUR
AREA BUT A RESIDUAL TROF REMAINS IN PLACE. MOISTURE WILL BEGIN TO
WANE BUT PWATS STILL HOVER AROUND OR JUST ABOVE NORMAL FOR MID
SEPTEMBER AND THIS WILL KEEP A THREAT OF SHOWERS AND THUNDERSTORMS
GOING INTO THE LATE PERIODS. TEMPERATURES THROUGH THE EXTENDED
PERIOD LOOK TO HOVER NEAR THE SEASONAL NORMALS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1109 PM MDT MON SEP 9 2013
RAINFALL CONTINUES FOR MUCH OF THE NEXT 24 HOURS. MVFR AND OCCNL
IFR IS EXPECTED THROUGH THE MORNING HOURS WITH LOW CIGS AND VIS UNDER
THE STRONGER SHOWERS AND STORMS THAT FORM. FOG WILL ALSO BE A
CONCERN ESPECIALLY IN THE MORNING DUE TO AMOUNT OF MOISTURE IN THE
AIR. ALL TAF SITES ARE UNDER THE GUN FOR PRECIP...LOW CLOUDS AND
VISIBILITIES THROUGH 06Z TOMORROW. MOUNTAIN OBSCURATIONS CAN BE
EXPECTED OVER ALL HIGHER TERRAIN.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR COZ003-017-020-021.
FLASH FLOOD WATCH FROM 9 AM MDT TUESDAY THROUGH TUESDAY EVENING
FOR COZ001-002-004>014-018-019-022-023.
UT...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR UTZ022-025-027>029.
&&
$$
UPDATE...PF
SHORT TERM...TGR
LONG TERM...15
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS ALBANY NY
203 AM EDT TUE SEP 10 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE WILL CONTINUE TO MOVE AWAY FROM
THE REGION TONIGHT. A WARM FRONT WILL APPROACH THE REGION LATE
TONIGHT AND MOVE ACROSS THE REGION TUESDAY...ALLOWING FOR THE CHANCE
FOR SOME SHOWERS AND STRONG THUNDERSTORMS...MAINLY FOR AREAS TO
THE NORTH OF THE MOHAWK RIVER AND INTERSTATE 90. MUCH WARMER AND
MUGGY AIR WILL BE IN PLACE THROUGH THURSDAY WITH A CONTINUED
CHANCE FOR SHOWERS AND THUNDERSTORMS...BEFORE A STRONG COLD FRONT
BRINGS COOLER WEATHER BACK TO THE REGION FOR THE LATE WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1230 AM EDT...SHOWERS ALONG WITH A FEW EMBEDDED
THUNDERSTORMS APPROACHING NW CORNER OF FA AND HAVE ADJUSTED POP
AND WEATHER GRIDS ACCORDING. THE HIGHER THERMAL AND THETA-E
GRADIENT MAGNITUDES WERE JUST NORTH OF THE GREAT LAKES REGION
ALONG WITH A WEST-SOUTHWEST LOW LEVEL JET. THE LINEAR CONVECTIVE
COMPLEX WAS DEVELOPING IN THE EASTERN U.P. OF MICHIGAN AND PER THE
CORFIDI AND 850-300 THICKNESS TRAJECTORIES...THERE IS THE
POTENTIAL FOR THIS UPSTREAM COMPLEX TO TRACK INTO UPSTATE NY
OVERNIGHT. LATEST HRRR REMAINS VERY AGGRESSIVE WITH TRACKING THIS
FEATURE INTO WESTERN NY LATE TONIGHT AND WEAKENING AS IT MOVES
ACROSS EASTERN NY AROUND SUNRISE. FOR NOW...WE RAISED POPS EARLIER
AND HAVE LEFT THOSE INTACT FOR THIS UPDATE. MODIFIED DEWPOINTS
UPWARD A BIT PER OBSERVATIONS AND LEFT OVERNIGHT LOWS PER THE
PREVIOUS FORECASTS.
AS OF 412 PM EDT...OUR REGION IS SITUATED ON THE NORTHERN SIDE OF
A STRONG RIDGE EXPANDING FROM THE CENTRAL PLAINS TOWARDS THE
SOUTHEASTERN CONUS. A SHORTWAVE EMBEDDED IN THE WESTERLY FLOW ON
THE TOP OF THE RIDGE IS MOVING ACROSS THE UPPER MIDWEST...AND IS
HEADED EASTWARD TOWARDS THE GREAT LAKES AND NORTHEAST.
MEANWHILE...HIGH PRESSURE OFF THE NEW ENGLAND COAST WILL CONTINUE TO
SLIDE EASTWARD AND AWAY FROM THE REGION TONIGHT. WHILE SKIES WILL
START OFF MOSTLY CLEAR/PARTLY CLOUDY...CLOUDS WILL INCREASE
THIS EVENING AND INTO THE OVERNIGHT AHEAD OF THE ADVANCING
SHORTWAVE. A SURFACE WARM FRONT WILL SITUATED ACROSS THE MIDWEST
AND MID ATLANTIC STATES...AND THIS WILL BE STARTING TO MOVE
NORTHEAST TOWARDS OUR AREA. THIS WARM FRONT CAN EASILY BE SEEN IN
THE OBSERVATIONS THIS AFTERNOON...WITH SIGNIFICANTLY WARMER TEMPS
IN THE UPPER 80S...AND DEWPOINTS IN THE UPPER 60S TO LOW 70S
ACROSS THE MIDWEST...AS WE SIT WITH TEMPS IN THE 60S AND DEWPOINTS
IN THE 40S ACROSS UPSTATE NY AND WESTERN NEW ENGLAND.
MODEL GUIDANCE SUGGESTS THAT A COMPLEX OF SHOWERS AND
THUNDERSTORMS...AIDED BY STRONG WARM AIR ADVECTION/ISENTROPIC
LIFT AND STEEP MID LEVEL LAPSE RATES...WILL MOVE EASTWARD ACROSS
ONTARIO AND THE ST. LAWRENCE VALLEY BY LATE TONIGHT. RIGHT
NOW...IT APPEARS THAT THE BULK OF THE ACTIVITY WILL REMAIN NORTH
OF OUR REGION...BUT THE SOUTHERN EXTENT OF THESE
SHOWERS/THUNDERSTORMS MAY BRUSH OUR ADIRONDACK ZONES. WE WILL GO
WITH CHC POPS FOR OUR NORTHERN ZONES FOR LATE TONIGHT...WITH
SLIGHT CHC POPS ELSEWHERE WITH THE APPROACH OF THE WARM FRONT.
WHILE SVR WX ISN/T ANTICIPATED WITH THIS ACTIVITY DUE TO THE
NOCTURNAL TIMING...HEAVY DOWNPOURS WILL BE POSSIBLE WITHIN ANY
THUNDERSTORM...DUE TO HIGHER PWAT AIR BEING ADVECTED INTO THE
REGION.
MIN TEMPS TONIGHT WON/T BE AS COOL AS RECENT NIGHTS...WITH MINS
GENERALLY IN THE 50S TO LOW 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
THERE WILL LIKELY BE SOME CONVECTIVE DEBRIS CLOUDS FOR TOMORROW
MORNING IN THE WAKE OF THE MORNING SHOWERS AND THUNDERSTORMS THAT
WILL BE MOVING ACROSS FAR NORTHERN PARTS OF THE AREA. DURING THE
MORNING HOURS...THE SFC WARM FRONT WILL BE LIFTING NORTHWARD...AND
DAYTIME MIXING SHOULD ALLOW FOR SOME BREAKS OF SUN TO EVENTUALLY
BREAK OUT.
ONCE THE SUN BREAKS OUT...TEMPS WILL BE MUCH WARMER THAN RECENT
DAYS...WITH LOW TO MID 80S ACROSS THE REGION...AND DEWPOINTS WILL
RETURN TO SUMMERLIKE LEVELS IN THE 60S. WITH THE WARM FRONT DRAPED
OR SLOWLY MOVING ACROSS THE NORTHERN PART OF THE AREA...THIS COULD
PROVIDE A FOCUS FOR ADDITIONAL SHOWER AND THUNDERSTORM
ACTIVITY...ESP DURING THE AFTN HOURS. ANY LINGERING BOUNDARIES
FROM THE MORNING CONVECTION COULD ALSO PROVIDE A FOCUS FOR
SHOWER/THUNDERSTORM DEVELOPMENT.
THERE IS THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS ON TUESDAY
FOR THE CENTRAL AND NORTHERN HALF OF THE AREA. 0-6 KM BULK SHEAR
VALUES WILL BE 30-40 KTS. IF SKIES CLEAR OUT ENOUGH AS THE MODELS
ANTICIPATE....THERE COULD BE AROUND 2000 J/KG OF CAPE. THE
PROXIMITY OF THE LOW LEVEL WARM FRONTAL BOUNDARY WOULD PROVIDE
SOME TURNING OF THE WINDS AT LOW LEVELS...AND THE 12Z NAM12 HAS
DEPICTED SOME IMPRESSIVE 0-1 KM HELICITY VALUES IN EXCESS OF 300
M2/S2 ACROSS OUR NORTHERN ZONES. ALSO IMPRESSIVE IS THE PRESENCE
OF AN ELEVATED MIXED LAYER /EML/ WITH MID LEVEL LAPSE RATES AT
700HPA-500HPA OF AROUND 7 C/KM.
IF DISCRETE CELLS DO DEVELOP...THERE WILL BE THE THREAT FOR
SUPERCELLS AND AN ISOLATED TORNADO TO DEVELOP...MAINLY FOR AREAS
TO THE NORTH OF MOHAWK VALLEY/I-90. WITH THE STRONG SHEAR...IT/S
POSSIBLE THAT ANY CELLS COULD MERGE AND ORGANIZE INTO BOW SEGMENTS OR
SQUALL LINE AS WELL...BRINGING A RISK OF DAMAGING WINDS. SPC HAS
PLACED THE CENTRAL/NORTHERN HALF OF OUR AREA IN A SLIGHT RISK FOR
SVR STORMS FOR TUESDAY. THE EXACT NATURE OF THE THREAT WILL HINGE ON
THE LOCATION OF THE SFC BOUNDARY DURING THE LATE MORNING/AFTN
HOURS...AND EXACTLY HOW MUCH INSTABILITY IS IN PLACE. IF THE FRONT
MOVES QUICKER AND/OR CLOUDS DO NOT CLEAR OUT...THE SVR THREAT WILL
BE LESS.
THE THREAT FOR SHOWERS AND THUNDERSTORMS WILL DIMINISH ON TUESDAY
NIGHT AS THE WARM FRONT LIFTS NORTHWARD...AND OUR REGION IS IN THE
WARM SECTOR. MIN TEMPS ON TUESDAY NIGHT WILL BE IN THE 60S TO NEAR
70 WITH MUGGY CONDITIONS IN PLACE. ON WEDNESDAY...THERE WILL BE A
LOW CHC OR SLIGHT CHC FOR A SHOWER OR THUNDERSTORM DURING THE AFTN
HOURS...OTHERWISE IT WILL BE HOT AND STICKY. MAX TEMPS LOOK TO
REACH INTO THE 90S. MUGGY AND WARM CONDITIONS WILL CONTINUE INTO
WED NIGHT WITH MINS AGAIN IN THE 60S TO NEAR 70 WITH A CONTINUED
LOW CHC THREAT FOR A SHOWER OR THUNDERSTORM.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THURSDAY THROUGH FRIDAY NIGHT...LATEST MODEL GUIDANCE SHOWS AN UPPER
LEVEL LONGWAVE TROUGH MOVING SOUTHEAST ACROSS THE GREAT LAKES FROM
WESTERN ONTARIO. WITH OUR AREA BEING DOWNSTREAM OF THE TROUGH
AXIS...A BROAD AREA OF UPPER LEVEL DIVERGENCE ALONG WITH A COLD
FRONT PASSAGE ASSOCIATED WITH A SURFACE LOW DEVELOPING IN
NORTHERN MAINE WILL BRING TO THE REGION A SCATTERED TO LIKELY
CHANCE OF SHOWERS AND THUNDERSTORMS ESPECIALLY AS WE GO INTO
THURSDAY AFTERNOON. PRECIPITATION WILL WORK ITS WAY ACROSS THE
AREA FROM NORTHWEST TO SOUTHEAST AS THE FRONT MOVES THROUGH THE
REGION AND AS THE LOW PRESSURE SYSTEM EXITS OFF THE COAST INTO THE
CANADIAN MARITIMES. HIGH TEMPERATURES ON THURSDAY AHEAD OF THE
COLD FRONT WITH A SOUTH-SOUTHWESTERLY FLOW WILL ALLOW TEMPS TO
WARM UP INTO THE MID AND UPPER 70S IN THE HIGH TERRAIN TO LOWER
80S ACROSS THE HUDSON VALLEY. AS WE GO INTO THE DAY ON FRIDAY
AFTER THE COLD FRONT PASSES THROUGH THE REGION...A MORE DEFINED
FALL AIR MASS WILL MOVE INTO THE REGION AS HIGH TEMPERATURES ON
FRIDAY WILL ONLY RANGE FROM THE LOW TO MID 50S IN THE HIGH TERRAIN
TO THE UPPER 50S AND LOWER 60S FOR THE REST OF THE REGION WITH A
MUCH DRIER AIRMASS TO ACCOMPANY THE COOLER HIGH TEMPS. WITH SOME
MODELS SHOWING A UPPER LEVEL LOW WITH LOWER 550 DM HEIGHTS...HIGH
TEMPS ON FRIDAY WILL BE ABOUT 10 DEGREES BELOW NORMAL. SLIGHT POPS
REMAIN FOR THE AREA ON FRIDAY AS LAKE ENHANCED SHOWERS ALONG THE
WEST SIDE OF THE DEPARTING UPPER LEVEL LOW MAY IMPACT SOME AREAS
ESPECIALLY NORTH AND WEST OF THE IMMEDIATE CAPITAL REGION. LATEST
GUIDANCE ALSO SHOWS LOW TEMPS ON FRIDAY TO BE BELOW AVERAGE AS
WELL AS WE GET INTO A DOMINANT NORTHWEST FLOW WITH LARGE AREAS OF
UPPER LEVEL CONVERGENCE AND CLEARING SKIES. LOWS ON FRIDAY NIGHT
WILL RANGE FROM THE LOWER 30S IN THE ADIRONDACKS TO MID AND UPPER
30S FOR THE REST OF THE HIGH TERRAIN TO LOWER 40S IN VALLEY
LOCATIONS. MODEL GUIDANCE SHOWS COOL TEMPS WITH T850 NEAR 0C IN
THE ADIRONDACKS ALONG WITH 1C-3C ACROSS THE REST OF THE AREA AND
T925 TEMPS RANGING FROM 3C-5C ACROSS THE ENTIRE AREA.
SATURDAY THROUGH MONDAY...THE REST OF THE EXTENDED PERIOD LOOKS TO
BE RATHER TRANQUIL AS A HIGH PRESSURE SYSTEM FROM THE OHIO VALLEY
MOVES INTO THE REGION ON SATURDAY AND SLOWLY MOVES TO THE EAST
ACROSS OUR REGION THROUGHOUT THE WEEKEND. OUR NEXT CHANCE OF
PRECIPITATION AHEAD OF THE NEXT FRONTAL SYSTEM MOVING ACROSS THE
GREAT LAKES WILL BE DURING THE DAY ON MONDAY WHERE PRE-FRONTAL
SHOWERS MAY APPEAR IN THE HIGH TERRAIN ACROSS THE ADIRONDACKS.
OTHERWISE...A PLEASANT SECOND HALF OF THE EXTENDED WITH HIGH TEMPS
DURING THIS TIME EXPECTED TO BE FROM THE UPPER 50S TO MID 60S ON
SATURDAY WITH A WARM UP BY SUNDAY AND MONDAY WITH HIGHS RANGING FROM
THE MID 60S IN THE HIGH TERRAIN TO LOWER 70S IN VALLEY LOCATIONS.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE CONTINUES TO MOVE EAST OF THE GULF OF MAINE. A WARM
FRONT CONTINUES TO APPROACH FROM THE LOWER GREAT LAKES
REGION...AND THE OHIO VALLEY. THE WARM FRONT WILL MOVE THROUGH ERN
NY AND WRN NEW ENGLAND IN THE AFTERNOON...AS A WARM AND HUMID AIR
MASS BUILDS IN FROM THE SOUTH.
VFR CONDITIONS WILL CONTINUE TO LOWER TO MVFR LEVELS AS MVFR
STRATUS FORMS...AND MOVES IN FROM THE SOUTH. ALSO...SPOTTY SHOWERS
WITH A WEAK MID LEVEL DISTURBANCE...AND A WARM FRONT WILL IMPACT
THE TERMINALS BTWN 09Z-14Z. A VCSH GROUP WAS USED IN THIS TIME
FRAME TO ADDRESS SOME LIGHT SHOWERS AROUND. CIGS WILL FALL INTO
THE 1.5-3.0 KFT AGL RANGE IN THE WARM ADVECTION REGIME. THE CIGS
SHOULD RISE BACK TO VFR LEVELS TOWARDS 16Z/NOONTIME/.
SOME POP-UP SHOWERS AND THUNDERSTORMS MAY FORM IN THE WARM
SECTOR...AS THE BOUNDARY RACES N/NE INTO QUEBEC. SOME VCSH GROUP
WERE USED HERE WITH CIGS IN THE 3.5-5 KFT AGL RANGE. THUNDERSTORM
PROBS MAY NEED TO BE ADDED WITH LATER TAFS.
THE SKIES WILL LIKELY CLEAR THIS EVENING WITH MORE MOISTURE IN THE
BOUNDARY LAYER...SOME PATCHY MIST OR FOG MAY FORM BEFORE MIDNIGHT.
THE WINDS WILL BE LIGHT AND VARIABLE THIS MORNING...EXCEPT AT KALB
WHERE SOUTHERLY WINDS AROUND 10 KTS WILL CONTINUE DUE TO THE
CONFLUENT FLOW UP THE HUDSON RIVER VALLEY. THE 2.0 KFT AGL WINDS
WILL INCREASE TO ABOUT 30 KTS...SO LLWS GROUPS WERE KEPT IN FROM
ROUGHLY 09Z-14Z AT KPOU/KPSF/KGFL. ONCE THE WARM FRONT MOVES
NORTH...LLWS WILL NOT BE AN ISSUE. EXPECT S/SW WIND OF 8-15 KTS
WITH SOME GUSTS CLOSE TO 25 KTS AT KALB IN THE AFTERNOON
OUTLOOK...
TUESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
WEDNESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
THURSDAY: MODERATE OPERATIONAL IMPACT. NUMEROUS SHRA...TSRA.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. SCATTERED SHRA...TSRA.
FRIDAY: LOW OPERATIONAL IMPACT. ISOLATED SHRA.
FRIDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER ARE ANTICIPATED OVER THE NEXT SEVERAL DAYS.
A WARM FRONT WILL TRACK THROUGH OUR AREA LATE TONIGHT INTO TOMORROW
WITH THE CHANCE FOR SHOWERS AND THUNDERSTORMS...MAINLY ACROSS
NORTHERN AREAS. THE THREAT FOR ADDITIONAL SHOWERS AND THUNDERSTORMS
WILL BE IN PLACE WEDNESDAY AND THURSDAY AS OUR REGION WILL BE IN A
WARM AND MUGGY AIR MASS AHEAD OF AN APPROACHING COLD FRONT. RH
VALUES WILL BE HIGH AT NIGHT...NEARLY 100 PERCENT AT TIMES. RH
VALUES WILL ONLY DROP TO 50 TO 60 PERCENT DURING THE DAYTIME HOURS.
&&
.HYDROLOGY...
THERE WILL BE A THREAT FOR SHOWERS AND THUNDERSTORMS OVER THE
SEVERAL DAYS AS A WARM FRONT MOVES THROUGH THE AREA TOMORROW...AND A
COLD FRONT ON THURSDAY. PWAT VALUES WILL BE QUITE HIGH OVER THE NEXT
FEW DAYS...WITH PWAT VALUES 1.50 TO 2.00 INCHES. THIS WILL ALLOW FOR
ANY SHOWER OR THUNDERSTORM TO BE CAPABLE OF PRODUCING VERY HEAVY
RAINFALL IN A SHORT PERIOD OF TIME. THUNDERSTORMS LOOK TO BE MOST
WIDESPREAD ON THURSDAY AHEAD OF THE ADVANCING COLD FRONT. THE THREAT
FOR HEAVY SHOWERS AND THUNDERSTORMS WILL END WITH THE PASSAGE OF THE
COLD FRONT LATE THURSDAY...WITH MUCH DRIER AND LESS HUMID WEATHER
FOR THE LATE WEEK PERIOD.
WITHIN ANY SHOWER OR THUNDERSTORM...THERE WILL BE THE POTENTIAL FOR
MINOR FLOODING OF POOR DRAINAGE...URBAN...AND LOW LYING AREAS DUE TO
VERY HEAVY RAINFALL IN A SHORT PERIOD OF TIME. WHILE WIDESPREAD MAIN
STEM RIVER FLOODING IS NOT ANTICIPATED OVER THE NEXT FEW
DAYS...THERE WILL BE SOME POTENTIAL FOR FLOODING OF SMALL CREEKS AND
STREAMS DUE TO THE THUNDERSTORM ACTIVITY.
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...FRUGIS
NEAR TERM...FRUGIS/BGM/11
SHORT TERM...FRUGIS
LONG TERM...LFM
AVIATION...WASULA
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1235 AM EDT TUE SEP 10 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE WILL CONTINUE TO MOVE AWAY FROM
THE REGION TONIGHT. A WARM FRONT WILL APPROACH THE REGION LATE
TONIGHT AND MOVE ACROSS THE REGION TUESDAY...ALLOWING FOR THE CHANCE
FOR SOME SHOWERS AND STRONG THUNDERSTORMS...MAINLY FOR AREAS TO
THE NORTH OF THE MOHAWK RIVER AND INTERSTATE 90. MUCH WARMER AND
MUGGY AIR WILL BE IN PLACE THROUGH THURSDAY WITH A CONTINUED
CHANCE FOR SHOWERS AND THUNDERSTORMS...BEFORE A STRONG COLD FRONT
BRINGS COOLER WEATHER BACK TO THE REGION FOR THE LATE WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1230 AM EDT...SHOWERS ALONG WITH A FEW EMBEDDED
THUNDERSTORMS APPROACHING NW CORNER OF FA AND HAVE ADJUSTED POP
AND WEATHER GRIDS ACCORDING. THE HIGHER THERMAL AND THETA-E
GRADIENT MAGNITUDES WERE JUST NORTH OF THE GREAT LAKES REGION
ALONG WITH A WEST-SOUTHWEST LOW LEVEL JET. THE LINEAR CONVECTIVE
COMPLEX WAS DEVELOPING IN THE EASTERN U.P. OF MICHIGAN AND PER THE
CORFIDI AND 850-300 THICKNESS TRAJECTORIES...THERE IS THE
POTENTIAL FOR THIS UPSTREAM COMPLEX TO TRACK INTO UPSTATE NY
OVERNIGHT. LATEST HRRR REMAINS VERY AGGRESSIVE WITH TRACKING THIS
FEATURE INTO WESTERN NY LATE TONIGHT AND WEAKENING AS IT MOVES
ACROSS EASTERN NY AROUND SUNRISE. FOR NOW...WE RAISED POPS EARLIER
AND HAVE LEFT THOSE INTACT FOR THIS UPDATE. MODIFIED DEWPOINTS
UPWARD A BIT PER OBSERVATIONS AND LEFT OVERNIGHT LOWS PER THE
PREVIOUS FORECASTS.
AS OF 412 PM EDT...OUR REGION IS SITUATED ON THE NORTHERN SIDE OF
A STRONG RIDGE EXPANDING FROM THE CENTRAL PLAINS TOWARDS THE
SOUTHEASTERN CONUS. A SHORTWAVE EMBEDDED IN THE WESTERLY FLOW ON
THE TOP OF THE RIDGE IS MOVING ACROSS THE UPPER MIDWEST...AND IS
HEADED EASTWARD TOWARDS THE GREAT LAKES AND NORTHEAST.
MEANWHILE...HIGH PRESSURE OFF THE NEW ENGLAND COAST WILL CONTINUE TO
SLIDE EASTWARD AND AWAY FROM THE REGION TONIGHT. WHILE SKIES WILL
START OFF MOSTLY CLEAR/PARTLY CLOUDY...CLOUDS WILL INCREASE
THIS EVENING AND INTO THE OVERNIGHT AHEAD OF THE ADVANCING
SHORTWAVE. A SURFACE WARM FRONT WILL SITUATED ACROSS THE MIDWEST
AND MID ATLANTIC STATES...AND THIS WILL BE STARTING TO MOVE
NORTHEAST TOWARDS OUR AREA. THIS WARM FRONT CAN EASILY BE SEEN IN
THE OBSERVATIONS THIS AFTERNOON...WITH SIGNIFICANTLY WARMER TEMPS
IN THE UPPER 80S...AND DEWPOINTS IN THE UPPER 60S TO LOW 70S
ACROSS THE MIDWEST...AS WE SIT WITH TEMPS IN THE 60S AND DEWPOINTS
IN THE 40S ACROSS UPSTATE NY AND WESTERN NEW ENGLAND.
MODEL GUIDANCE SUGGESTS THAT A COMPLEX OF SHOWERS AND
THUNDERSTORMS...AIDED BY STRONG WARM AIR ADVECTION/ISENTROPIC
LIFT AND STEEP MID LEVEL LAPSE RATES...WILL MOVE EASTWARD ACROSS
ONTARIO AND THE ST. LAWRENCE VALLEY BY LATE TONIGHT. RIGHT
NOW...IT APPEARS THAT THE BULK OF THE ACTIVITY WILL REMAIN NORTH
OF OUR REGION...BUT THE SOUTHERN EXTENT OF THESE
SHOWERS/THUNDERSTORMS MAY BRUSH OUR ADIRONDACK ZONES. WE WILL GO
WITH CHC POPS FOR OUR NORTHERN ZONES FOR LATE TONIGHT...WITH
SLIGHT CHC POPS ELSEWHERE WITH THE APPROACH OF THE WARM FRONT.
WHILE SVR WX ISN/T ANTICIPATED WITH THIS ACTIVITY DUE TO THE
NOCTURNAL TIMING...HEAVY DOWNPOURS WILL BE POSSIBLE WITHIN ANY
THUNDERSTORM...DUE TO HIGHER PWAT AIR BEING ADVECTED INTO THE
REGION.
MIN TEMPS TONIGHT WON/T BE AS COOL AS RECENT NIGHTS...WITH MINS
GENERALLY IN THE 50S TO LOW 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
THERE WILL LIKELY BE SOME CONVECTIVE DEBRIS CLOUDS FOR TOMORROW
MORNING IN THE WAKE OF THE MORNING SHOWERS AND THUNDERSTORMS THAT
WILL BE MOVING ACROSS FAR NORTHERN PARTS OF THE AREA. DURING THE
MORNING HOURS...THE SFC WARM FRONT WILL BE LIFTING NORTHWARD...AND
DAYTIME MIXING SHOULD ALLOW FOR SOME BREAKS OF SUN TO EVENTUALLY
BREAK OUT.
ONCE THE SUN BREAKS OUT...TEMPS WILL BE MUCH WARMER THAN RECENT
DAYS...WITH LOW TO MID 80S ACROSS THE REGION...AND DEWPOINTS WILL
RETURN TO SUMMERLIKE LEVELS IN THE 60S. WITH THE WARM FRONT DRAPED
OR SLOWLY MOVING ACROSS THE NORTHERN PART OF THE AREA...THIS COULD
PROVIDE A FOCUS FOR ADDITIONAL SHOWER AND THUNDERSTORM
ACTIVITY...ESP DURING THE AFTN HOURS. ANY LINGERING BOUNDARIES
FROM THE MORNING CONVECTION COULD ALSO PROVIDE A FOCUS FOR
SHOWER/THUNDERSTORM DEVELOPMENT.
THERE IS THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS ON TUESDAY
FOR THE CENTRAL AND NORTHERN HALF OF THE AREA. 0-6 KM BULK SHEAR
VALUES WILL BE 30-40 KTS. IF SKIES CLEAR OUT ENOUGH AS THE MODELS
ANTICIPATE....THERE COULD BE AROUND 2000 J/KG OF CAPE. THE
PROXIMITY OF THE LOW LEVEL WARM FRONTAL BOUNDARY WOULD PROVIDE
SOME TURNING OF THE WINDS AT LOW LEVELS...AND THE 12Z NAM12 HAS
DEPICTED SOME IMPRESSIVE 0-1 KM HELICITY VALUES IN EXCESS OF 300
M2/S2 ACROSS OUR NORTHERN ZONES. ALSO IMPRESSIVE IS THE PRESENCE
OF AN ELEVATED MIXED LAYER /EML/ WITH MID LEVEL LAPSE RATES AT
700HPA-500HPA OF AROUND 7 C/KM.
IF DISCRETE CELLS DO DEVELOP...THERE WILL BE THE THREAT FOR
SUPERCELLS AND AN ISOLATED TORNADO TO DEVELOP...MAINLY FOR AREAS
TO THE NORTH OF MOHAWK VALLEY/I-90. WITH THE STRONG SHEAR...IT/S
POSSIBLE THAT ANY CELLS COULD MERGE AND ORGANIZE INTO BOW SEGMENTS OR
SQUALL LINE AS WELL...BRINGING A RISK OF DAMAGING WINDS. SPC HAS
PLACED THE CENTRAL/NORTHERN HALF OF OUR AREA IN A SLIGHT RISK FOR
SVR STORMS FOR TUESDAY. THE EXACT NATURE OF THE THREAT WILL HINGE ON
THE LOCATION OF THE SFC BOUNDARY DURING THE LATE MORNING/AFTN
HOURS...AND EXACTLY HOW MUCH INSTABILITY IS IN PLACE. IF THE FRONT
MOVES QUICKER AND/OR CLOUDS DO NOT CLEAR OUT...THE SVR THREAT WILL
BE LESS.
THE THREAT FOR SHOWERS AND THUNDERSTORMS WILL DIMINISH ON TUESDAY
NIGHT AS THE WARM FRONT LIFTS NORTHWARD...AND OUR REGION IS IN THE
WARM SECTOR. MIN TEMPS ON TUESDAY NIGHT WILL BE IN THE 60S TO NEAR
70 WITH MUGGY CONDITIONS IN PLACE. ON WEDNESDAY...THERE WILL BE A
LOW CHC OR SLIGHT CHC FOR A SHOWER OR THUNDERSTORM DURING THE AFTN
HOURS...OTHERWISE IT WILL BE HOT AND STICKY. MAX TEMPS LOOK TO
REACH INTO THE 90S. MUGGY AND WARM CONDITIONS WILL CONTINUE INTO
WED NIGHT WITH MINS AGAIN IN THE 60S TO NEAR 70 WITH A CONTINUED
LOW CHC THREAT FOR A SHOWER OR THUNDERSTORM.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THURSDAY THROUGH FRIDAY NIGHT...LATEST MODEL GUIDANCE SHOWS AN UPPER
LEVEL LONGWAVE TROUGH MOVING SOUTHEAST ACROSS THE GREAT LAKES FROM
WESTERN ONTARIO. WITH OUR AREA BEING DOWNSTREAM OF THE TROUGH
AXIS...A BROAD AREA OF UPPER LEVEL DIVERGENCE ALONG WITH A COLD
FRONT PASSAGE ASSOCIATED WITH A SURFACE LOW DEVELOPING IN
NORTHERN MAINE WILL BRING TO THE REGION A SCATTERED TO LIKELY
CHANCE OF SHOWERS AND THUNDERSTORMS ESPECIALLY AS WE GO INTO
THURSDAY AFTERNOON. PRECIPITATION WILL WORK ITS WAY ACROSS THE
AREA FROM NORTHWEST TO SOUTHEAST AS THE FRONT MOVES THROUGH THE
REGION AND AS THE LOW PRESSURE SYSTEM EXITS OFF THE COAST INTO THE
CANADIAN MARITIMES. HIGH TEMPERATURES ON THURSDAY AHEAD OF THE
COLD FRONT WITH A SOUTH-SOUTHWESTERLY FLOW WILL ALLOW TEMPS TO
WARM UP INTO THE MID AND UPPER 70S IN THE HIGH TERRAIN TO LOWER
80S ACROSS THE HUDSON VALLEY. AS WE GO INTO THE DAY ON FRIDAY
AFTER THE COLD FRONT PASSES THROUGH THE REGION...A MORE DEFINED
FALL AIR MASS WILL MOVE INTO THE REGION AS HIGH TEMPERATURES ON
FRIDAY WILL ONLY RANGE FROM THE LOW TO MID 50S IN THE HIGH TERRAIN
TO THE UPPER 50S AND LOWER 60S FOR THE REST OF THE REGION WITH A
MUCH DRIER AIRMASS TO ACCOMPANY THE COOLER HIGH TEMPS. WITH SOME
MODELS SHOWING A UPPER LEVEL LOW WITH LOWER 550 DM HEIGHTS...HIGH
TEMPS ON FRIDAY WILL BE ABOUT 10 DEGREES BELOW NORMAL. SLIGHT POPS
REMAIN FOR THE AREA ON FRIDAY AS LAKE ENHANCED SHOWERS ALONG THE
WEST SIDE OF THE DEPARTING UPPER LEVEL LOW MAY IMPACT SOME AREAS
ESPECIALLY NORTH AND WEST OF THE IMMEDIATE CAPITAL REGION. LATEST
GUIDANCE ALSO SHOWS LOW TEMPS ON FRIDAY TO BE BELOW AVERAGE AS
WELL AS WE GET INTO A DOMINANT NORTHWEST FLOW WITH LARGE AREAS OF
UPPER LEVEL CONVERGENCE AND CLEARING SKIES. LOWS ON FRIDAY NIGHT
WILL RANGE FROM THE LOWER 30S IN THE ADIRONDACKS TO MID AND UPPER
30S FOR THE REST OF THE HIGH TERRAIN TO LOWER 40S IN VALLEY
LOCATIONS. MODEL GUIDANCE SHOWS COOL TEMPS WITH T850 NEAR 0C IN
THE ADIRONDACKS ALONG WITH 1C-3C ACROSS THE REST OF THE AREA AND
T925 TEMPS RANGING FROM 3C-5C ACROSS THE ENTIRE AREA.
SATURDAY THROUGH MONDAY...THE REST OF THE EXTENDED PERIOD LOOKS TO
BE RATHER TRANQUIL AS A HIGH PRESSURE SYSTEM FROM THE OHIO VALLEY
MOVES INTO THE REGION ON SATURDAY AND SLOWLY MOVES TO THE EAST
ACROSS OUR REGION THROUGHOUT THE WEEKEND. OUR NEXT CHANCE OF
PRECIPITATION AHEAD OF THE NEXT FRONTAL SYSTEM MOVING ACROSS THE
GREAT LAKES WILL BE DURING THE DAY ON MONDAY WHERE PRE-FRONTAL
SHOWERS MAY APPEAR IN THE HIGH TERRAIN ACROSS THE ADIRONDACKS.
OTHERWISE...A PLEASANT SECOND HALF OF THE EXTENDED WITH HIGH TEMPS
DURING THIS TIME EXPECTED TO BE FROM THE UPPER 50S TO MID 60S ON
SATURDAY WITH A WARM UP BY SUNDAY AND MONDAY WITH HIGHS RANGING FROM
THE MID 60S IN THE HIGH TERRAIN TO LOWER 70S IN VALLEY LOCATIONS.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS ARE EXPECTED UNTIL THE WARM FRONT GETS CLOSER AND
CIGS LOWER DUE TO WARM AIR ADVECTION WITH MVFR CONDITIONS
EXPECTED OVERNIGHT. AN IMPROVEMENT BACK TO VFR WILL OCCUR WITH
THE WARM FRONTAL PASSAGE DURING THE DAYLIGHT MORNING HOURS
TUESDAY.
THERE WILL BE A CHANCE FOR CONVECTION LATER TONIGHT AS THE
STRENGTH OF WARM ADVECTION AND FORCING WILL RESULT IN SOME
SCATTERED ACTIVITY. HOWEVER...WE WILL PLACE `VCSH` AT THIS TIME
UNTIL TRENDS UNFOLD UPSTREAM.
WE ARE EXPECTED TO BE WELL INTO THE WARM SECTOR TUESDAY AS
CONVECTIVE TRENDS WILL BECOME A CHALLENGE. AT THIS TIME...WE WILL
KEEP THE MENTION OUT OF THE TAFS...
SOUTH WINDS 5 TO 10 KNOTS WILL DIMINISH THIS EVENING. LOW LEVEL
WINDS WILL INCREASE TO AROUND 30 KNOTS OVERNIGHT SO HAVE CONTINUED
LOW LEVEL WIND SHEAR IN TAFS. ONCE THE WARM FRONT MOVES BY THREAT OF
LLWS WILL END AND SOUTH-SOUTHWEST SURFACE FLOW WILL DEVELOP WITH
GUSTY CONDITIONS EXPECTED...MORE NOTICEABLE AT KALB.
OUTLOOK...
TUESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
WEDNESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
THURSDAY: MODERATE OPERATIONAL IMPACT. NUMEROUS SHRA...TSRA.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. SCATTERED SHRA...TSRA.
FRIDAY: LOW OPERATIONAL IMPACT. ISOLATED SHRA.
FRIDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER ARE ANTICIPATED OVER THE NEXT SEVERAL DAYS.
A WARM FRONT WILL TRACK THROUGH OUR AREA LATE TONIGHT INTO TOMORROW
WITH THE CHANCE FOR SHOWERS AND THUNDERSTORMS...MAINLY ACROSS
NORTHERN AREAS. THE THREAT FOR ADDITIONAL SHOWERS AND THUNDERSTORMS
WILL BE IN PLACE WEDNESDAY AND THURSDAY AS OUR REGION WILL BE IN A
WARM AND MUGGY AIR MASS AHEAD OF AN APPROACHING COLD FRONT. RH
VALUES WILL BE HIGH AT NIGHT...NEARLY 100 PERCENT AT TIMES. RH
VALUES WILL ONLY DROP TO 50 TO 60 PERCENT DURING THE DAYTIME HOURS.
&&
.HYDROLOGY...
THERE WILL BE A THREAT FOR SHOWERS AND THUNDERSTORMS OVER THE
SEVERAL DAYS AS A WARM FRONT MOVES THROUGH THE AREA TOMORROW...AND A
COLD FRONT ON THURSDAY. PWAT VALUES WILL BE QUITE HIGH OVER THE NEXT
FEW DAYS...WITH PWAT VALUES 1.50 TO 2.00 INCHES. THIS WILL ALLOW FOR
ANY SHOWER OR THUNDERSTORM TO BE CAPABLE OF PRODUCING VERY HEAVY
RAINFALL IN A SHORT PERIOD OF TIME. THUNDERSTORMS LOOK TO BE MOST
WIDESPREAD ON THURSDAY AHEAD OF THE ADVANCING COLD FRONT. THE THREAT
FOR HEAVY SHOWERS AND THUNDERSTORMS WILL END WITH THE PASSAGE OF THE
COLD FRONT LATE THURSDAY...WITH MUCH DRIER AND LESS HUMID WEATHER
FOR THE LATE WEEK PERIOD.
WITHIN ANY SHOWER OR THUNDERSTORM...THERE WILL BE THE POTENTIAL FOR
MINOR FLOODING OF POOR DRAINAGE...URBAN...AND LOW LYING AREAS DUE TO
VERY HEAVY RAINFALL IN A SHORT PERIOD OF TIME. WHILE WIDESPREAD MAIN
STEM RIVER FLOODING IS NOT ANTICIPATED OVER THE NEXT FEW
DAYS...THERE WILL BE SOME POTENTIAL FOR FLOODING OF SMALL CREEKS AND
STREAMS DUE TO THE THUNDERSTORM ACTIVITY.
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...FRUGIS
NEAR TERM...FRUGIS/BGM/11
SHORT TERM...FRUGIS
LONG TERM...LFM
AVIATION...IAA/BGM
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
344 AM EDT TUE SEP 10 2013
.SYNOPSIS...
A WARM FRONT WAS LIFTING THROUGH OUR REGION EARLY THIS MORNING.
VERY WARM HIGH PRESSURE IS FORECAST TO INFLUENCE NORTHEASTERN
MARYLAND, DELAWARE, EASTERN PENNSYLVANIA AND NEW JERSEY DURING THE
MID WEEK PERIOD. A STRONG COLD FRONT IS EXPECTED TO APPROACH FROM
THE NORTHWEST ON THURSDAY AND IT SHOULD PASS THROUGH OUR REGION ON
THURSDAY NIGHT. HIGH PRESSURE IS ANTICIPATED TO FOLLOW FOR FRIDAY
AND FOR THE WEEKEND. ANOTHER COLD FRONT FROM THE NORTHWEST MAY
ARRIVE EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW PRESSURE NR THE NR GRTLKS WAS SLOWLY MOVG EWD AND ITS ASSOCD
WMFNT WAS MOVG THRU THE AREA. THIS FRONT WILL BRING A MARKED RISE
IN TEMPS OVER THE NEXT FEW DAYS, BEGINNING WITH TODAY AN HAD
TRIGGERED SOME EARLIER SHOWERS OVER NERN PA. HOWEVER, LATEST RADAR
IMAGERY INDICATED THAT THESE SHOWERS HAVE ALL BUT FALLEN APART.
LATEST HRRR GUID INDICATES THAT REGION SHUD REMAIN DRY THRU THE
ERLY MRNG AND ALL OF THE GUID INDICATES A DRY DAY, SO WILL REMOVE
ALL POPS ATTM, EXCEPT FOR EXTREME NRN NJ. TEMPS WILL AVERAGE 7 TO
10 DEGREES ABV NRML. THIS WILL ULTIMATELY DEPEND ON HOW QUICKLY WE
CLEAR OUT. LATEST GUID INDICATES THAT THE MRNG WILL START OUT
FAIRLY CLOUDY WITH LINGERING STRATUS, BUT BY LATE MRNG/ERLY AFTN
THE SKY WILL BECOME MOSTLY SUNNY AND TEMPS SHUD WARM QUITE NICELY
AS SWLY FLOW INCREASES, WELL INTO THE 80S AND PSBLY EVEN PUSH 90
IN SOME AREAS, IF THE WARMER MET MOS IS CORRECT. DEW POINTS WILL
RISE AS WELL MAKING FOR THE START OF A RATHER UNCOMFORTABLE
PERIOD.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
WITH THE AFOREMENTIONED LOW OVER ERN CANADA AND HIGH PRESSURE
BUILDING TO THE S, WE WILL BE IN THE WARM SECTOR AND IT WILL BE A
RATHER UNEVENTFUL NIGHT. TEMPS WILL REMAIN WARM AND DEW POINTS
WILL INCREASE A BIT MORE SO A HUMID NIGHT IS IN STORE.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
VERY WARM AIR SHOULD BE IN PLACE OVER OUR REGION FOR WEDNESDAY.
TEMPERATURES AT 850 HPA ARE FORECAST TO CLIMB AROUND +19C TO +20C
WITH THE WARMEST OF THE AIR BEING ACROSS THE NORTH. TEMPERATURES
ARE EXPECTED TO REACH THE LOWER 90S IN MUCH OF OUR FORECAST AREA.
ONE EXCEPTION WILL BE THE ELEVATED TERRAIN UP NORTH WHERE HIGH
TEMPERATURES SHOULD BE IN THE UPPER 80S. MAXIMUM READINGS IN THE
80S ARE ANTICIPATED RIGHT ALONG THE COAST. DEW POINT TEMPERATURES
NEAR 70 SHOULD RESULT IN MAXIMUM HEAT INDEX VALUES IN THE MIDDLE
9OS AT MOST LOCATIONS.
THERE WILL BE RELATIVELY MILD TEMPERATURES AND SOME RIDGING ALOFT
ON WEDNESDAY LIMITING CONVECTIVE DEVELOPMENT. WE WILL CONTINUE TO
MENTION A CHANCE OF MAINLY AFTERNOON THUNDERSTORMS IN OUR
NORTHWESTERN COUNTIES FOR WEDNESDAY. WE ARE NOT EXPECTING ANY
PRECIPITATION ALONG THE INTERSTATE 95 CORRIDOR OR ON THE COASTAL
PLAIN.
THE CORE OF THE WARM AIR IS EXPECTED TO LIFT TO OUR NORTHEAST ON
WEDNESDAY NIGHT AND THURSDAY. TEMPERATURES AT 850 HPA ARE FORECAST
TO SLIP DOWN INTO THE +17C TO +18C RANGE FOR THURSDAY AFTERNOON.
MAXIMUM READINGS AT THE SURFACE ARE EXPECTED TO BE GENERALLY ABOUT
3F TO 5F DEGREES LOWER THAN THOSE ON WEDNESDAY. THE DIFFERENCE MAY
BE A BIT GREATER IF THERE IS MORE CLOUD COVER THAN ANTICIPATED.
THE MID LEVEL RIDGE WILL LIKELY CONTINUE TO LOSE ITS INFLUENCE
OVER OUR WEATHER ON THURSDAY. THERE SHOULD BE AN INCREASING CHANCE
OF SHOWERS AND THUNDERSTORMS AS A STRONG COLD FRONT BEGINS TO
APPROACH FROM THE NORTHWEST. IT APPEARS AS THOUGH THE COLD FRONT
WILL PUSH THROUGH OUR REGION LATE ON THURSDAY NIGHT. ADDITIONAL
SHOWERS AND THUNDERSTORMS ARE EXPECTED FOR THURSDAY EVENING IN
ADVANCE OF THE BOUNDARY.
STRONG COLD ADVECTION IS EXPECTED FOR LATE THURSDAY NIGHT AND
FRIDAY. MAXIMUM TEMPERATURES ON FRIDAY SHOULD BE ABOUT 15 TO 20
DEGREES COOLER THAN THOSE ON THURSDAY.
HIGH PRESSURE IS FORECAST TO BRING DRY WEATHER AND BELOW NORMAL
TEMPERATURES FOR SATURDAY AND SUNDAY.
ANOTHER COLD FRONT FROM THE NORTHWEST IS EXPECTED TO ARRIVE ON
MONDAY. THE 0000 UTC GFS BRINGS THE BOUNDARY THROUGH OUR REGION
DRY WHILE THE 0000 UTC ECMWF INDICATES SOME SHOWERS WITH THE
FRONT. BEING THAT WE ARE NOT GETTING A UNIFIED SIGNAL AT THIS
TIME, WE WILL LEAVE THE MENTION OF PRECIPITATION OUT OF MONDAY`S
FORECAST, AT LEAST FOR THE TIME BEING.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
CONDS RANGED FROM VFR TO MVFR ACRS THE REGION EARLY THIS MRNG.
THERE COULD BE A BIT MORE DETERIORATION TWD DAY BREAK AND ITS
STILL PSBL TO SEE SOME FOG, BUT IT APPEARS THAT ANY WIDESPREAD IFR
CONDS WILL BE AVOIDED.
CONDS WILL REMAIN GENLY MVFR UNTIL MID MRNG THEN IMPROVE TO VFR
FOR THE BALANCE OF THE DAY. THERE COULD BE SOME LCL MVFR FOG
OVERNIGHT AS DEW POINTS CONTINUE TO INCREASE IN WHAT WOULD NRMLY
BE A SUMMERTIME AMS.
THE WIND IS EXPECTED TO BE SWLY GENLY INCREASING TO AROUND 10 KTS
DURG THE AFTN BEFORE DIMINISHING TO 5-8 KTS AFTER SUNSET.
OUTLOOK...
WEDNESDAY...MAINLY VFR AFTER POSSIBLE EARLY MORNING VISIBILITY
RESTRICTIONS. A CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS NEAR
KRDG AND KABE.
WEDNESDAY NIGHT...MAINLY VFR EARLY, THEN POSSIBLE LOW CLOUDS AND
VISIBILITY RESTRICTIONS LATE.
THURSDAY...MAINLY VFR AFTER POSSIBLE EARLY MORNING LOW CLOUDS AND
VISIBILITY RESTRICTIONS. A CHANCE OF SHOWERS AND THUNDERSTORMS
WHICH MAY BE ACCOMPANIED BY IFR CONDITIONS.
THURSDAY NIGHT...MAINLY VFR. A CHANCE OF SHOWERS AND
THUNDERSTORMS MAINLY IN THE EVENING.
FRIDAY THROUGH SATURDAY...MAINLY VFR.
&&
.MARINE...
RELATIVELY QUIET CONDS ARE EXPECTED ON THE AREA WATERS WITH SEAS
IN THE 3 TO 4 FT RANGE AND A SW WIND GENLY 10 TO 15 KT WITH GUSTS
TO AROUND 20 KT. NO SCA FLAGS ARE ANTICIPATED DURG THE NEAR AND
SHORT TERM PDS.
OUTLOOK...
HIGH PRESSURE IS FORECAST TO INFLUENCE THE COASTAL WATERS OF NEW
JERSEY AND DELAWARE FOR WEDNESDAY AND THURSDAY. A STRONG COLD
FRONT FROM THE NORTHWEST IS EXPECTED TO ARRIVE LATE ON THURSDAY
NIGHT FOLLOWED BY ANOTHER AREA OF HIGH PRESSURE FOR FRIDAY AND
SATURDAY. WIND GUSTS MAY REACH OR EXCEED 25 KNOTS FROM FRIDAY INTO
SATURDAY IN THE COLD ADVECTION. WAVE HEIGHTS ON OUR OCEAN WATERS
MAY APPROACH 5 FEET AT THAT TIME.
&&
.CLIMATE...
THE MOST RECENT 90 DEGREES IN OUR AREA THIS SUMMER /CLIMATE
SITES/...
ACY...AUGUST 9.
PHL...JULY 21.
ILG...JULY 21.
ABE...JULY 20.
RDG...JULY 20.
TTN...JULY 20.
GED...JULY 24.
MPO...JULY 18.
RECORD HIGH TEMPERATURES FOR SEPTEMBER 11TH ARE MOSTLY OUT OF
REACH, HOWEVER THEY ARE INCLUDED BELOW AS A REFERENCE...
ABE....96 IN 1983.
ACY....99 IN 1983.
ILG...100 IN 1983.
MPO....89 IN 1983. HAS A GOOD CHANCE OF BEING NEAR RECORD.
PHL....98 IN 1983.
RDG....98 IN 1983.
TTN...100 IN 1983.
GED....92 IN 1989 /DATA MISSING FOR 1983/.
NOTE: PER MEDIA INQUIRY. LATEST EVER 90F IN PHL OCT 10
1939.
AVG NUMBER OF SEPTEMBER 90 DEGREE DAYS IN PHL 1.1.
ALL TIME PHL SEPT RECORD 102 ON SEPT 7 1881.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...NIERENBERG
SHORT TERM...NIERENBERG
LONG TERM...IOVINO
AVIATION...IOVINO/NIERENBERG
MARINE...IOVINO/NIERENBERG
CLIMATE...DRAG
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
352 AM EDT TUE SEP 10 2013
.DISCUSSION...
TODAY-TONIGHT...
H100-H70 RIDGE AXIS EXTENDING FROM THE SRN PLAINS INTO THE
CENTRAL ATLC NE GOMEX TO NOVA SCOTIA WILL GENERATE A DEEP E/NE
FLOW REGIME ACRS CENTRAL FL. DUE TO THE ELONGATED NATURE OF THE
RIDGE THE ERLY FETCH EXTENDS WELL PAST THE BAHAMA BANK TO THE
REMNANT CIRCULATION OF FORMER T.C. GABRIELLE.
WITH SUCH A CLEAR SOURCE REGION...THE FCST IS PRETTY STRAIGHT
FORWARD. THE IMMEDIATE UPSTREAM AIRMASS IS ON THE DRY SIDE...LATEST
RUC ANALYSIS SHOWS THE H100-H70 MEAN RH VALUES AS LOW AS 50PCT E OF
KJAX...INCREASING TO ARND 80PCT OVER THE NRN BAHAMAS. A DEEP
MOISTURE TONGUE BEHIND THE DRY AIR SLUG WILL PUSH INTO THE FL
PENINSULA EVENTUALLY...BUT NOT UNTIL AFT SUNSET.
ALOFT...A RIPPLE IN THE H85-H50 VORT FIELD EMBEDDED IN THE ERLY FLOW
N OF THE BAHAMAS WILL GENERATE SOME MID LVL SUPPORT FOR PRECIP.
HOWEVER...THIS WILL BE COUNTERED BY THE POSITION OF A HIGH AMPLITUDE
TUTT AXIS EXTENDING FROM THE SE GOMEX ACRS S FL. THIS FEATURE HAS
BEEN NEARLY STATIONARY FOR THE PAST SEVERAL HRS DUE TO THE CUTOFF
LOW N OF THE BAHAMAS...AS CUTOFFS ARE SO WONT TO DO.
BOTH GFS AND ECMWF DRIFT THE TUTT AXIS SLOWLY NW THRU SUNRISE
WED...BUT MOST OF THE CWA WILL BE UNDER THE INFLUENCE OF ITS
DESCENDING FLANK THRU SUNSET. FURTHERMORE...DEEP E/NERLY FLOW
REGIMES TEND TO FAVOR THE W FL PENINSULA FOR HIGHEST PRECIP
COVERAGE. POPS WILL REFLECT THE MOISTURE PROFILE WITH BLO 20PCT OVER
THE NRN CWA...INCREASING TO 30PCT OVER THE SRN COUNTIES. WILL KEEP
TSRAS ISOLD AND LIMIT THEM TO THE INTERIOR COUNTIES AS NE FLOW
TYPICALLY DOES NOT SUPPORT DEEP CONVECTION OVER THE E CENTRAL
PENINSULA. MAX TEMPS WITHIN A DEG OR TWO OF 90F.
DEEP 10-15KT ERLY FLOW WILL CONTINUE OVERNIGHT WHILE THE TUTT AXIS
DRIFTS NWD ACRS THE CENTRAL PENINSULA...GRADUALLY PLACING THE CWA
UNDER ITS ASCENDING FLANK. BY THEN...THE DEEP MOISTURE NE OF THE
BAHAMAS WILL HAVE PUSHED FAR ENOUGH INTO THE CWA TO REQUIRE MENTION
OF A SLGT CHC OF SHRAS ALL COUNTIES OVERNIGHT. ONSHORE FLOW WILL
KEEP MIN TEMPS A FEW DEG ABV AVG (L/M70S).
WED-THU...
MAIN FEATURE OF NOTE WILL BE MID-UPPER LEVEL COLD LOW THAT IS
FORECAST TO MOVE SLOWLY NORTHWEST INTO CENTRAL FLORIDA WED AND
THEN SHIFT NORTH OF THE AREA THU. AT THE SURFACE...A HIGH PRESSURE
RIDGE NORTH OF THE STATE WILL BRING AN ONSHORE FLOW 10-15 MPH ON
WED...THEN THE RIDGE WILL WEAKEN THU AND SHIFT CLOSER TO CENTRAL
FLORIDA. THIS WILL CAUSE ONSHORE FLOW TO WEAKEN...HOWEVER THE GFS
INDICATES A WEAK LOW LEVEL TROUGH AFFECTING THE AREA.
MOISTURE IS FORECAST TO INCREASE THROUGH THE PERIOD SO EXPECT
SCATTERED POPS 30-40 PERCENT WED AND 40-50 PERCENT THU.
WITH COLDER TEMPS ALOFT...SOME AFTERNOON STORMS...ESPECIALLY
ACROSS THE INTERIOR...SHOULD BE STRONG.
FRI-WEEKEND...
MID TO UPPER LEVEL TROUGH SHOULD LIFT OUT TO THE NORTHEAST BY
EARLY FRI BUT WEAK SURFACE RIDGE AXIS NEAR OKEECHOBEE WILL DELAY
INLAND PUSH OF THE SEA BREEZE. THIS SHOULD ALLOW FOR ISOLATED
AFTERNOON STORMS TO FORM ON THE SLOWLY INLAND MOVING SEA
BREEZE...THEN COVERAGE SHOULD INCREASE TO SCATTERED BY LATE
AFTERNOON AS BOUNDARY INTERACTIONS BECOME MORE NUMEROUS.
OVER THE WEEKEND...A WEAK FRONTAL TROUGH IS FORECAST TO PUSH
SOUTH OVER THE ATLANTIC WATERS AND GRADUALLY WASH OUT. WEAK HIGH
PRESSURE RIDGE VICINITY EAST CENTRAL FLORIDA ON SAT WILL CAUSE
LIGHT WINDS AND EXPECT POPS AROUND 30 PERCENT COAST AND 40 PERCENT
INLAND. STRONGER HIGH PRESSURE BUILDING NORTH OF THE REGION ON
SUNDAY WILL PRODUCE ONSHORE LOW LEVEL FLOW AND RATHER UNIFORM POPS
AROUND 30 PERCENT EXPECTED.
MON-TUE...
THE ONSHORE FLOW PATTERN WILL CONTINUE THROUGH EARLY NEXT WEEK.
THIS WILL FAVOR NIGHT/MORNING RAIN CHANCES ALONG THE COAST AND THE
GREATEST CHANCE FOR STORMS TO BE INLAND DURING THE AFTERNOON.
&&
.AVIATION...
THRU 10/17Z...E/NE SFC WNDS 4-8KTS INCREASING TO 10-12KTS BTWN
12Z-14Z...BRIEF MVFR SHRAS COASTAL SITES. BTWN 10/17Z-10/24Z...E/NE
SFC WND G20-23KTS ALL SITES...SCT MVFR SHRAS/ISOLD IFR TSRAS S OF
KVRB-KGIF...ISOLD MVFR SHRAS/IFR TSRAS N OF KVRB-KGIF...STORM MOTION
W/SW ARND 15-20KTS. AFT 11/24Z...E/NE SFC WNDS DIMINISHING TO
4-8KTS...ISOLD MVFR SHRAS ALL SITES.
&&
.MARINE...
TODAY-TONIGHT...
ELONGATED SFC RIDGE EXTENDING FROM THE NE GOMEX TO NOVA SCOTIA
WILL GENERATE A GENTLE TO MODERATE ERLY BREEZE ACRS THE LCL ATLC.
THESE WINDS WILL CONTINUE TO PUSH A 2-3FT ERLY SWELL INTO THE E FL
COAST. DATA BUOYS CONFIRM THIS WITH 2-3FT SEAS NEARSHORE AND 3-4FT
SEAS OFFSHORE. MOST RECENT OBS SHOW THE DOMINANT PDS HAVE FALLEN
FROM 8-9SEC DOWN TO 4-6SEC. LATEST RUC ANALYSIS DOES SHOW A SMALL
WIND SURGE UPSTREAM WITH SFC/LOW LVL WINDS ARND 15KTS ON COURSE TO
AFFECT THE LCL ATLC AFT SUNRISE. THE 10/00Z SWAN GUIDANCE HAS
PICKED UP ON THIS BY DROPPING SHORTENING THE DOMINANT PDS OVER THE
NEARSHORE LEG BLO 6SEC BY EARLY AFTN...THEN INTO THE OFFSHORE
WATERS OVERNIGHT.
WED-SAT...
EAST FLOW ON WED LOOKS TO BE 10-15 KNOTS WITH SCATTERED SHOWERS
AND ISOLATED STORMS OCCURRING...EVEN DURING THE DAY AS A MID-UPPER
LEVEL LOW WILL BE NEARBY.
ONSHORE WINDS WILL DIMINISH TO 10 KNOTS OR LESS ON THU AND STILL
EXPECT SCATTERED SHOWERS AND ISOLATED STORMS DUE TO HIGH MOISTURE
AND A TROUGH ALOFT.
HIGH PRESSURE RIDGE OVER CENTRAL TO SOUTH CENTRAL FLORIDA ON FRI
SHOULD PRODUCE A LIGHT OFFSHORE WIND FLOW. SCATTERED AFTERNOON
STORMS OVER THE MAINLAND MAY PUSH BACK TO THE COAST OR AT LEAST
PRODUCE GUSTY OUTFLOW BOUNDARY WINDS THAT AFFECT THE COAST.
WEAK HIGH PRESSURE RIDGE NEARBY ON SAT SHOULD PRODUCE WINDS LESS
THAN 10 KNOTS. SCATTERED AFTERNOON STORMS SHOULD REMAIN OVER THE
MAINLAND.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 88 74 89 74 / 20 20 30 20
MCO 91 74 92 72 / 20 20 30 20
MLB 88 74 89 74 / 20 20 30 20
VRB 88 73 89 73 / 20 20 30 20
LEE 91 72 92 74 / 20 20 30 20
SFB 90 74 92 74 / 20 20 30 20
ORL 91 75 91 75 / 20 20 30 20
FPR 88 73 88 73 / 30 20 40 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...BRAGAW
LONG TERM....LASCODY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
350 AM EDT TUE SEP 10 2013
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS NORTHERN STREAM FLOW
RIDING THROUGH THE GREAT LAKES/NEW ENGLAND REGION OVER THE TOP OF
LONGWAVE RIDGING CENTERED OVER THE SE CONUS. EASTERN PERIPHERY OF
THIS RIDGE IS BEING PUSHED BACK BY AN ORGANIZING UPPER LEVEL LOW
SPINNING OFF THE GA/NE FLORIDA COAST. THIS UPPER LOW WILL RETROGRADE
DURING THE NEXT 24-30 HOURS TO A POSITION OVER CENTRAL AND NORTHERN
FLORIDA. 00Z KTBW SOUNDING STILL SHOWED A FAIRLY DRY PROFILE ABOVE
750MB WITH A DEEP MIXED BOUNDARY LAYER. THE LOWER PORTION OF THIS
PROFILE IS MORE REMINISCENT OF THE WELL MIXED DAYS WE SEE DURING THE
LATE SPRING. THE DRY MID/UPPER LEVELS NOTED ON THE SOUNDING ARE
DISPLAYED WELL IN THE EARLY MORNING WV IMAGERY OVER THE STATE. THIS
DEEP AND HOSTILE LAYER TO DEEP CONVECTION WILL HOLD ON FOR ANOTHER
DAY...WITH THE CONTINUING TREND OF THE DEEPEST AND MOST HOSTILE
AIRMASS FROM THE TAMPA BAY AREA NORTHWARD THROUGH THE NATURE COAST.
THE AIRMASS ALOFT ALONG WITH GENERAL SYNOPTIC SUPPRESSION ARE
KEEPING SKIES MOSTLY CLEAR THIS MORNING.
AT THE SURFACE...1020+MB HIGH PRESSURE IS CENTERED OVER THE
MID-ATLANTIC/CAROLINAS AND EXTENDS SOUTH TO THE FL PENINSULA AND
NORTHEAST GULF OF MEXICO. THE EXPECTED NOCTURNAL SURGE OVER THE
COASTAL WATERS DEVELOPED DURING THE LATE EVENING WITH MANY COASTAL
AND OFFSHORE STATIONS SEEING WINDS BETWEEN 15-20KTS WITH EVEN SOME
HIGHER GUSTS AT A FEW SPOTS LIKE CEDAR KEY. THE HIGH POSITION AND
STRENGTH WILL FAVOR ONE MORE NIGHT WITH A POTENTIALLY CAUTIONARY
LEVEL SURGE OVER THE COASTAL WATERS BEGINNING SHORTLY AFTER SUNSET
THIS EVENING.
&&
.SHORT TERM (TODAY THROUGH THURSDAY)...
TODAY/TONIGHT...
THE DRY AIR ALOFT WILL CONTINUE TO HINDER DEEP CONVECTION
DEVELOPMENT. WITH STRONG HIGH PRESSURE CENTERED TO OUR NORTH...THE
LOW LEVEL FLOW HAS BECOME DEFINED EASTERLY FOR ALL ZONES. THIS FLOW
WILL HELP TO FOCUS AT LEAST SOME LOW LEVEL CONVERGENCE ALONG THE
FLORIDA WEST COAST...CAUSE OTHERWISE EVEN ISOLATED STORMS WOULD BE
HARD TO DEVELOP UNDER THIS ENVIRONMENT. THE FLOW APPEARS TOO STRONG
IN ORDER TO ALLOW A DEFINED SEA-BREEZE TO DEVELOP...HOWEVER AT LEAST
SOME WEAKENING/COLLAPSE OF THE LOCAL GRADIENT DURING THE AFTERNOON
ACROSS THE NEAR SHORE WATERS SHOULD ALLOW MODEST SPEED CONVERGENCE
NEAR THE COAST. WITH THIS IN MIND WILL CONTINUE THE FORECAST OF 30%
POPS FOR WIDELY SCT LATE AFTERNOON/EVENING STORMS SOUTH OF
HILLSBOROUGH AND POLK COUNTIES. UNDER THE "BEST" MOISTURE PROFILE
WILL DRAW A SMALL AREA OF 40% POPS AROUND FORT MYERS AFTER 4PM.
CONVECTIVE DEVELOPMENT FROM TAMPA BAY NORTHWARD ACROSS THE NATURE
COAST AGAIN LOOKS ISOLATED AT BEST. WILL KEEP THE 20% FOR THE I-4
CORRIDOR OF THE STATE...BUT THEN DROP RAIN CHANCES TO A SILENT 10%
NORTH OF PASCO COUNTY. THE DEPTH AND STRENGTH OF THE SYNOPTIC
SUPPRESSION OVER THESE FAR NORTHERN ZONES SIMPLY DOES NOT WARRANT
STORM MENTION IN THE CURRENT FORECAST. CROSS SECTIONAL ANALYSIS FROM
THE GFS AND NAM ALSO SHOW A LAYER OF 315-318K THETA-E AIR BETWEEN
750-700MB THIS AFTERNOON TO THE NORTH OF THE I-4 CORRIDOR. THIS IS A
VERY HOSTILE LAYER FOR ANYTHING BUT ISOLATED DEEP CONVECTION TO
OVERCOME. THESE RAIN CHANCES LIE A BIT ABOVE THE STATISTICAL
GUIDANCE...BUT WELL BELOW THE CLIMO RAIN CHANCES ASSOCIATED WITH AN
EASTERLY FLOW REGIME.
THE LACK OF CONVECTION...EVEN SOUTH...UNTIL VERY LATE IN THE DAY
ALONG WITH THE DEEP LAYER SUPPRESSION SHOULD PROMOTE ANOTHER DAY OF
EXCELLENT DIURNAL MIXING. WOULD EXPECT MANY LOCATIONS TO EASILY
REACH THE LOWER/MIDDLE 90S FOR HIGH TEMPS.
WEDNESDAY/WEDNESDAY NIGHT...UPPER LOW FEATURE IS SHOWN BY ALL
NUMERICAL GUIDANCE MEMBERS TO RETROGRADE OVER THE CENTRAL AND
NORTHERN PORTION OF THE STATE BY EARLY WEDNESDAY MORNING. THIS
FEATURE SHOULD BRING AT LEAST SOME INCREASE IN DEEP LAYER
MOISTURE...ALTHOUGH CERTAINLY NOT GOING TO MAKE THE ATMOSPHERE MOIST
OVERHEAD...BUT RATHER POTENTIALLY NOT QUITE AS HOSTILE TO DEEP
CONVECTION. IN ADDITION TO THE SLIGHTLY BETTER MOISTURE
PROFILES...WE WILL SEE OUR MID-LEVEL TEMPS DROP A FEW DEGREES
ASSOCIATED WITH THE COOL POOL UNDER THE UPPER LOW. THIS SLIGHT TEMP
DROP SHOULD AID THE DECREASE IN STABILITY. INHERITED RAIN CHANCES OF
25-35% NORTH AND 35-50% SOUTH LOOK ON TRACK. THESE NUMBERS AGREE
WELL WITH ECMWF AND MAV STATISTICAL GUIDANCE SOUTH OF TAMPA
BAY...AND ARE A BIT ABOVE THESE NUMBERS FOR THE NORTHERN HALF OF THE
AREA.
WITH THE UPPER LOW IN PLACE OVER THE REGION WED NIGHT AND AN INFLUX
OF DEEP MOISTURE (SHOWN BY BOTH THE ECMWF AND GFS) APPROACHING FROM
THE SOUTH...WILL LEAVE AT LEAST A SMALL CHANCE FOR SHOWERS IN THE
GRIDS. QUITE OFTEN IT IS FAVORABLE TO SEE SHOWERS DEVELOP (EVEN AT
NIGHT) ALONG THESE MOISTURE GRADIENTS.
THURSDAY...UPPER LOW OPENS UP AND LEAVES THE REGION UNDER BROAD
SW TO NE ORIENTED TROUGHING. LOW LEVEL GRADIENT COLLAPSES COMPLETELY
LEAVING A VARIABLE WIND FLOW. THE LACK OF A DEFINED FLOW
REGIME...ADEQUATE MOISTURE AND SOME SYNOPTIC SUPPORT ALOFT WILL LEAD
TO CHANCE 40-50% POPS REGION-WIDE. SHOWERS MAY CERTAINLY BE AROUND
IN THE MORNING...HOWEVER THE GREATEST CHANCE OF SEEING A DOWNPOUR
WILL BE DURING THE AFTERNOON DURING PEAK INSOLATION / HEATING.
&&
.LONG TERM (FRIDAY THROUGH NEXT MONDAY)...
N UPPER LEVEL TROUGH RESIDES DOWN THE EASTERN BOARD INTO FL THROUGH
SUN. THIS TROUGH BEGINS TO SHIFTS OUT OVER THE ATLANTIC MON AS
RIDGING BUILDS IN OVER THE LOWER MISSISSIPPI VALLY/ 09/12Z ECMWF/ OR
ACROSS THE CENTRAL AND EASTERN GULF REGION/ 10/00Z GFS/. AT THE
SURFACE HIGH PRESSURE FROM THE ATLANTIC RIDGES ACROSS FL INTO THE
GULF THROUGH THE WEEKEND AS A FRONTAL BOUNDARY SAGS ACROSS THE SE
U.S TO NORTHERN FL AND BECOMES DIFFUSE. HIGH PRESSURE OVER THE LOWER
GREAT LAKES/MID-ATLANTIC STATES BRIDGES WHATEVER IS LEFT OF THE
BOUNDARY LATE SUN AND ON MON. THE ECMWF AND GFS ARE FAIRLY
CONSISTENT WITH AN AREA OF LOW PRESSURE IN THE SW GULF THAT DRIFTS
WEST OR NW THROUGH THE PERIOD.
THE FORECAST AREA INITIALLY IS UNDER THE INFLUENCE OF LIGHT FLOW
WITH AFTERNOON SEA BREEZES. HOWEVER THIS GIVES WAY TO MORE EASTERLY
FLOW AS THE HIGH BUILDS IN FROM THE NORTH. THE ATMOSPHERE REMAINS
MOIST ENOUGH FOR ISOLATED TO SCATTERED THUNDERSTORMS WITH THE
HIGHEST COVERAGE IN THE AFTERNOONS. RAIN CHANCES WILL BE GENERALLY
IN THE 30 TO 40/50 PERCENT RANGE...FROM NORTH TO SOUTH.
&&
.MARINE...
NOCTURNAL EASTERLY SURGE HAS DROPPED BACK BELOW CAUTIONARY LEVELS
NEAR THE COAST AND WILL DIMINISH OFFSHORE BY SHORTLY AFTER SUNRISE.
AFTER A BRIEF LULL IN THE ELEVATED WINDS THIS AFTERNOON...ANOTHER
EASTERLY SURGE TO CAUTIONARY LEVELS IS ANTICIPATED FOR THE LATE
EVENING AND EARLY MORNING HOURS TONIGHT. THEREAFTER...HIGH PRESSURE
WILL BUILD SOUTH OVER THE EASTERN GULF OF MEXICO AND DIMINISH WINDS
AND SEAS WELL BELOW HEADLINE CRITERIA FOR THE SECOND HALF OF THE
WEEK.
&&
.AVIATION...
10/06Z...PREVAILING VFR FOR THE NEXT 24 HOURS. GENERALLY DRY EXCEPT
FOR ISOLD SHRA/TSRA NEAR PGD/FMY/RSW AFTER 19Z. EASTERLY
WINDS...ROBUST AT TIMES IN THE LATE AFTERNOON-EARLY EVENING.
&&
.FIRE WEATHER...
HIGH PRESSURE TO OUR NORTH KEEPS AN EASTERLY FLOW IN PLACE THROUGH
WEDNESDAY ACROSS THE PENINSULA. WILL BEGIN TO SEE A SLOW INCREASE IN
ATLANTIC MOISTURE ONCE AGAIN DURING THE MIDDLE OF THE WEEK...ALONG
WITH SLOWLY INCREASING CHANCES FOR DIURNAL STORMS FURTHER NORTH INTO
THE TAMPA BAY AND NATURE COAST ZONES. NOT ANTICIPATING ANY CRITICAL
LEVELS OF RELATIVE HUMIDITY THE NEXT SEVERAL DAYS...HOWEVER
DISPERSION INDICES WILL BE ON THE HIGH SIDE...ESPECIALLY FROM THE
I-4 CORRIDOR NORTHWARD.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 93 75 92 75 / 20 10 30 20
FMY 92 75 91 74 / 40 20 50 30
GIF 92 72 91 72 / 20 10 30 20
SRQ 92 74 91 73 / 30 10 40 30
BKV 92 69 92 70 / 20 10 30 20
SPG 93 78 90 77 / 20 10 30 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1152 PM CDT MON SEP 9 2013
.SHORT TERM.../TONIGHT /...
ISSUED AT 324 PM CDT MON SEP 9 2013
MAIN FORECAST CONCERN IS WITH WEAK FRONT EXPECTED TO DIP INTO FAR
NORTHERN IOWA OVERNIGHT TONIGHT. LATEST HOPWRF SUGGEST SOME WEAK
ISOLATED DEVELOPMENT ALONG THE FRONT PAST 05Z TUESDAY IN SOUTHERN
MINNESOTA AND NORTHWEST IOWA. THE HRRR AND 4.0 SPC WRF SUGGEST
SIMILAR TREND...ALTHOUGH SLIGHTLY FURTHER NORTHWEST. THERE IS SOME
WEAK FRONTOGENETICAL FORCING BETWEEN 850MB AND 700MB LATER TONIGHT
INTO EARLY TUESDAY MORNING THAT SNEAKS INTO NORTHWEST IOWA. SO
KEPT SLIGHT POPS GOING ACROSS THE NORTH TONIGHT...BUT HAVE LOW
CONFIDENCE WITH ANY SIGNIFICANT RAINFALL SINCE SHOWERS WILL BE
VERY HIGH BASED. WENT CLOSER TO THE ECMWF FOR LOW TEMPS TONIGHT
WITH THE WAA CONTINUING AHEAD OF THE FRONT.
.LONG TERM.../TUESDAY THROUGH MONDAY/...
ISSUED AT 324 PM CDT MON SEP 9 2013
MAIN FORECAST CONCERNS FOR TUESDAY INT WEDNESDAY REVOLVE AROUND A
COLD FRONTAL PASSAGE. MOST OF THE FORCING WITH THE FRONT SHIFTS
NORTH AND EAST OF THE AREA. WHILE DEEP SHEAR IS UNIMPRESSIVE THERE
IS SOME LOW LEVEL SHEAR COINCIDENT WITH THE FRONT. MODELS CONTINUE
TO SHOW LITTLE IN THE WAY OF RAINFALL AND THAT BEING POST FRONTAL.
THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL COME LATE
AFTERNOON AND EVENING WHEN A SHORT WAVE MOVES ACROSS MAINLY THE
NORTHERN FORECAST AREA AND INTERACTS WITH THE FRONT. SOUNDINGS
SHOW STEEP LAPSE RATES SO WHILE ANY STORMS WOULD BE ISOLATED TO
SCATTERED AT BEST THERE IS SOME POTENTIAL FOR AN ISOLATED WIND
THREAT. THE HEAT WILL STILL BE ON FOR SOUTHEAST PORTIONS OF THE
STATE TOMORROW AND THERE IS SOME CONCERN THAT WITH TWO WARM NIGHTS
NOW AND WHAT WILL BE THE SECOND HOT DAY THERE COULD BE SOME
CUMULATIVE EFFECTS OF PROLONGED HEAT. HOWEVER WITH LONGER NIGHTS
THERE SHOULD BE MORE TIME FOR THE BODY TO RECOVER SO WE WILL
CONTINUE TO HANDLE THE HEAT WITH A SPECIAL WEATHER STATEMENT.
THE FRONT GRADUALLY SHIFTS TO THE SOUTH THROUGH WEDNESDAY FOLLOWED
BY COOLER TEMPS FOR THE REST OF THE WEEK.
FOR THE WEEKEND THE MODELS SUGGEST A SHORTWAVE PUSHING ACROSS THE
NORTHERN PLAINS AGAIN AND POSSIBLY INTO THE UPPER MIDWEST. TIMING
AND STRENGTH OF THE SHORTWAVE ARE STILL IN QUESTION BUT THERE
APPEAR TO BE AT LEAST CHANCES FOR THUNDERSTORMS AND GRIDS CONTINUE
TO REFLECT THESE CHANCES.
&&
.AVIATION...10/06Z
ISSUED AT 1147 PM CDT MON SEP 9 2013
WEAK SURFACE FRONT WILL SETTLE INTO THE STATE OVER THE DURATION OF
THE FORECAST PERIOD. DESPITE THE ARRIVAL OF THE BOUNDARY...
CONDITIONS WILL REMAIN VFR ACROSS THE FORECAST AREA THROUGH
TUESDAY. SOME ISOLATED TO SCATTERED CONVECTION IS EXPECTED TUESDAY
EVENING IN VICINITY OF THE FRONT. WINDS WILL BE LIGHT AND VARIABLE
NEAR THE FRONT WITH SOUTHWEST WINDS SOUTH OF THE BOUNDARY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...FAB/PODRAZIK
LONG TERM...FAB
AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1116 PM MDT MON SEP 9 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 237 PM MDT MON SEP 9 2013
AS OF 3 PM CDT...2 PM MDT...SKIES ACROSS THE TRI-STATE AREA WERE
MOSTLY CLEAR WITH THE EXCEPTION OF SOME PATCHES OF DAYTIME CUMULUS.
TEMPERATURES HAVE RISEN INTO THE LOW 90S TO NEAR 100 IN A FEW SPOTS
ACROSS RED WILLOW...DECATUR...NORTON AND GRAHAM COUNTIES. WINDS WERE
GENERALLY FROM THE SOUTH AT 10 TO 20 MPH WITH GUSTS 25 TO 30 MPH.
DEWPOINTS WERE ON A SLOW DECLINE THIS AFTERNOON. A COLD FRONT WAS
LOCATED ACROSS NORTHEAST COLORADO AND SOUTHWEST NEBRASKA. AN AREA OF
LOW PRESSURE WAS DRAPED ACROSS THE AREA...STRETCHING FROM SOUTHWEST
NEBRASKA TO THE COLORADO FRONT RANGE. FIRE WEATHER HAS BECOME A
CONCERN THIS AFTERNOON AND WILL BE ADDRESSED IN A FIRE WEATHER
SECTION BELOW.
FOR THIS AFTERNOON AND TONIGHT...SURFACE CONVERGENCE IS PROJECTED TO
INCREASE ALONG THE COLD FRONT...ALLOWING SOME ISOLATED TO WIDELY
SCATTERED THUNDERSTORMS TO DEVELOP. IN ADDITION...CONVECTION
DEVELOPING OVER THE ROCKIES MAY ORGANIZE AND MOVE EAST INTO THE
REGION FROM THE LATEST RUNS OF THE HRRR MODEL. MOST OTHER MODELS
HOLD ALL PRECIPITATION OFF AND KEEP IT TO THE NORTHWEST OF THE
FORECAST AREA. A STRONG STORM OR TWO IS POSSIBLE WITH DAMAGING
WINDS AND SMALL HAIL AS THE MAIN THREAT. HOWEVER...INSTABILITY IS
NOT AS HIGH AS NEEDED FOR A MORE WIDESPREAD THREAT OF SEVERE
WEATHER. THE FRONT SHOULD MOVE TO THE SOUTH DURING THE OVERNIGHT
HOURS...BRINGING COOLER TEMPERATURES...MORE MOISTURE TO THE AIR
AND A WIND SHIFT. LOW TEMPERATURES WILL VARY ACROSS THE REGION
WITH LOW 60S ACROSS EAST COLORADO AND MID 60S TO NEAR 70 FOR THE
REST OF THE AREA.
FOR TOMORROW...THE COLD FRONT IS EXPECTED TO STALL ACROSS THE AREA.
IN ADDITION TO THE FRONT...AN UPPER LEVEL DISTURBANCE WILL APPROACH
FROM THE WEST...PROVIDING EXTRA LIFT FOR SHOWER AND THUNDERSTORM
DEVELOPMENT. CHANCES FOR PRECIPITATION WILL BE MUCH HIGHER DURING
THE LATE AFTERNOON TO EVENING HOURS FOR A LARGER AREA. TEMPERATURES
BEHIND THE FRONT WILL BE NOTICEABLY COOLER WITH HIGHS IN THE UPPER
70S TO LOW 80S. ALONG AND AHEAD OF THE FRONT...TEMPERATURES WILL BE
WARM WITH HIGHS IN THE MID 80S TO LOW 90S WHERE DAYTIME HEATING
LASTS LONGER BEFORE CLOUDS AND CONVECTIVE ACTIVITY DEVELOPS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 1249 PM MDT MON SEP 9 2013
PATTERN CHANGE WILL OCCUR DURING THIS PERIOD AS THE UPPER RIDGE
WHICH HAS BEEN DOMINANT WILL SHIFT TO THE SOUTHEASTERN CONUS AND
TROUGH WHICH HAS BEEN OVER THE WEST WILL MOVE TO THE CENTRAL AND
NORTHERN ROCKIES. THIS WILL BRING NEAR TO BELOW NORMAL
TEMPERATURES AND OCCASIONAL CHANCES FOR PRECIPITATION TO THE AREA.
FIRST CHANCE FOR RAIN WILL OCCUR TUESDAY NIGHT WITH SHORTWAVE
TROUGH MOVING UP IN THE SOUTHWEST FLOW ALOFT. ANOTHER SHORTWAVE IS
FORECAST ON THURSDAY. BOTH SYSTEMS WILL HAVE PLENTIFUL MOISTURE TO
WORK WITH A TROPICAL CONNECTION TO THE BAJA. RAIN CHANCES CONTINUE
THROUGH THE WEEKEND AS THE UPPER LOW OPENS UP AND EVENTUALLY GETS
ENTRAINED IN THE NORTHERN STREAM. LATE IN THE PERIOD AN UPPER RIDGE
WILL BEGIN TO REBUILD BEHIND THE DEPARTING SYSTEM SIGNALING THE
RETURN OF WARM AND DRY CONDITIONS EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1116 PM MDT MON SEP 9 2013
VFR CONDITIONS SHOULD PREVAIL THROUGH THE TAF PERIOD AT BOTH KGLD
AND KMCK TERMINALS. WITH MOSTLY CLEAR SKIES AND WINDS BECOMING
LIGHT BY SUNRISE I COULDNT RULE OUT SHALLOW FOG OR ISOLATED
STRATUS WITH BL MOISTURE INCREASING NORTHEAST OF FRONT. AT THIS
POINT CONFIDENCE IS VERY LOW IN OCCURRENCE AT EITHER TERMINAL...AND
GUIDANCE CONTINUES TO KEEP CONDITIONS CLEAR...SO I WILL NOT ADD
DURING THIS ISSUANCE. WE COULD CONTINUE TO SEE A FEW BRIEF GUSTS
IMMEDIATELY BEHIND A FRONT THAT IS CURRENTLY JUST NORTH OF KMCK
EXTENDING EAST OF KGLD. OTHER THAN BRIEF GUSTS EARLY WINDS SHOULD
REMAIN BELOW 12KT WITH GRADIENT FAIRLY WEAK. THUNDERSTORMS WILL BE
POSSIBLE TUE AFTERNOON/EVENING...HOWEVER CONFIDENCE WAS TOO LOW TO
ADD MENTION FOR EITHER TERMINAL.
&&
.FIRE WEATHER...
ISSUED AT 237 PM MDT MON SEP 9 2013
NEAR CRITICAL FIRE WEATHER CONDITIONS HAVE DEVELOPED ACROSS PORTIONS
OF THE REGION THIS AFTERNOON. HOT TEMPERATURES AND LOW DEWPOINTS
HAVE LEAD TO RELATIVE HUMIDITIES DROPPING OFF INTO THE 15-25 PERCENT
RANGE. WINDS HAVE BEEN GUSTY AND A FEW LOCATIONS WERE BARELY MEETING
CRITERIA. HOWEVER...WHETHER OR NOT THE CONDITIONS WOULD LAST THE
FULL THREE HOURS TO MEET WARNING CRITERIA HAS BEEN PROBLEMATIC AS
THE WINDS HAVE BEEN BOUNCING UP AND DOWN THIS AFTERNOON. IN
ADDITION...A SLIGHT RISE IN DEWPOINTS FROM SOUTH TO NORTH HAS BEEN
NOTED AS A MORE MOIST AIR MASS ADVECTS IN FROM THE SOUTH. AS A
RESULT...CONFIDENCE WAS NOT QUITE HIGH ENOUGH TO GO AHEAD AND
ISSUE A RED FLAG WARNING FOR REDWILLOW...HITCHCOCK...DECATUR...
HOXIE...SHERIDAN...THOMAS....ST FRANCIS AND SHERMAN COUNTIES. IF
IT BECOMES APPARENT THAT WINDS WILL STAY UP...A SHORT DURATION RED
FLAG WARNING MAY BE REQUIRED. WILL UPDATE THE FIRE WEATHER
FORECAST TO REFLECT THE LATEST TRENDS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...RRH
LONG TERM...024
AVIATION...DR
FIRE WEATHER...RRH
AREA FORECAST DISCUSSION
NWS JACKSON KY
135 AM EDT TUE SEP 10 2013
.UPDATE...
ISSUED AT 135 AM EDT TUE SEP 10 2013
MADE SOME MINOR TWEAKS TO GET THE FIRST 12 HOURS OF THE FORECAST TO
BETTER REFLECT CURRENT CONDITIONS AND MODEL TRENDS. THE REST OF THE
FORECAST IS ON TRACK AND NO NEW ZONE FORECASTS WILL BE ISSUED.
UPDATE ISSUED AT 747 PM EDT MON SEP 9 2013
AS ANTICIPATED SHOWERS HAVE ALL DISSIPATED...LEAVING BEHIND MAINLY
CLEAR SKIES FOR THE REMAINDER OF THE NIGHT. WILL UPDATE FORECAST TO
REFLECT LESS CLOUD COVER OVERNIGHT AS WELL AS ADJUSTING LOWS DOWN A
TAD TOWARDS WHAT WE SAW LAST NIGHT. THIS SHOULD YIELD ANOTHER NIGHT
OF VALLEY FOG WITH DEWPOINTS ACTUALLY RUNNING A FEW DEGREES HIGHER
THAN YESTERDAY AT THIS TIME.
UPDATE ISSUED AT 553 PM EDT MON SEP 9 2013
A FEW SHOWERS AND THUNDERSTORMS HAVE DEVELOPED NORTHWARD INTO SOUTH
CENTRAL KENTUCKY...BASICALLY EASTERN WAYNE COUNTY/MCCREARY
COUNTY...NORTH INTO EASTERN PULASKI COUNTY. BASED ON SATELLITE...THIS
ACTIVITY SHOULD REMAIN CONFINED TO THESE AREAS OVER THE NEXT HOUR OR
TWO BEFORE WEAKENING AND DISSIPATING AS THE SUN GOES DOWN. THIS
SHOULD ALLOW ACTIVITY TO DIE OFF BY ROUGHLY 00Z. UPDATED NDFD GRIDS
TO REFINE THE POPS...BUT WILL NOT ISSUE A NEW ZFP WITH THE ISOLATED
NATURE OF THIS ACTIVITY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 340 PM EDT MON SEP 9 2013
18Z SFC ANALYSIS SHOWS WEAK HIGH PRESSURE IN PLACE OVER EAST KENTUCKY
WITH LOW PRESSURE FOUND OFF TO THE NORTHWEST. A DOME OF HIGHER
HEIGHTS IS BUILDING OVER THE REGION AND THIS HAS HELPED TO CONTRIBUTE
TO A VERY WARM LATE SUMMER DAY ACROSS EAST KENTUCKY WITH TEMPS
APPROACHING 90 DEGREES. PRETTY HIGH DEWPOINTS IN THE MID AND UPPER
60S ARE MAKING IT FEEL EVEN WARMER...IN ADDITION TO PROVIDING AN
UNCOMFORTABLE HUMIDITY LEVEL. HERE AT PEAK HEATING...A FEW OF THE CU
HAVE MANAGED TO GET DEEP ENOUGH THAT A SHOWER OR THUNDERSTORM WILL
BE POSSIBLE...MAINLY ALONG OUR SOUTHERN AND EASTERN BORDERS.
OTHERWISE...SKIES ARE MOSTLY CLEAR AND THE CU SHALLOW.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
DEPICTING A MODERATELY STRONG RIDGE PUSHING INTO THE LOWER OHIO
VALLEY AND ACROSS TO THE MID ATLANTIC COAST. THIS RIDGE WILL NOT BE
COMPLETELY FREE OF ENERGY OR PROHIBITIVELY WARM AT MID LEVELS...
THOUGH...SO ITS ABILITY TO PUT A CAP ON CONVECTION WILL BE LIMITED.
IN THIS KIND OF ENVIRONMENT...THE MESOSCALE WILL DOMINATE FOR WEATHER
SPECIFICS SO HAVE FAVORED A MORE SUBDUED VERSION OF THE NAM12 WITH
INPUT FROM THE HRRR IN THE NEAR TERM. ALSO FAVORED AN ENHANCED
DIURNAL TRACE FOR POPS.
SENSIBLE WEATHER WILL FEATURE MORE IN THE WAY OF PERSISTENCE THROUGH
WEDNESDAY MORNING. AT NIGHT...WE CAN EXPECT A FADE OUT OF THE
DAYTIME CLOUDS AND PATCHY FOG...LOCALLY DENSE IN THE VALLEYS...
DEVELOPING BY DAWN. HIGH DEWPOINTS WILL KEEP THERE FROM BEING MUCH OF
A RIDGE TO VALLEY TEMP SPLIT BOTH TONIGHT AND TUESDAY NIGHT. FOR THE
DAY TUESDAY...IT WILL BE ANOTHER WARM AND HUMID ONE WITH A SMALL
CHANCE OF SHOWERS AND THUNDERSTORMS DEVELOPING WITH PEAK HEATING...
DESPITE THE RIDGING ALOFT.
JUMP STARTED THE TD AND WIND GRIDS WITH CONSSHORT DATA THROUGH 12Z
TUESDAY AND THE CONSALL THEREAFTER. FOR TEMPERATURES...PREFERRED THE
OBS DATABASE AS A GUIDE FOR THE DIURNAL CURVE AND MODIFIED CONSALL
FOR MAX AND MIN TEMPS...TEMPERING THE TOO WARM GRIDDED MOS HIGHS ON
TUESDAY WITH SOME RAW MODEL OUTPUT. AS FOR POPS...ENDED UP PRETTY
CLOSE TO AN AVERAGE OF THE GUIDANCE THROUGH THE SHORT TERM PERIOD.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 245 PM EDT MON SEP 9 2013
THE MODELS ALL AGREE THAT WEDNESDAY AND THURSDAY WILL BE THE ACTIVE
DAYS OF THE EXTENDED PERIOD. A SERIES OF WEATHER SYSTEMS...BOTH
SURFACE FRONTS AND TROUGHS OF LOW PRESSURE ALOFT...WILL BRING
SHOWERS AND THUNDERSTORMS TO EASTERN KENTUCKY DURING THE MIDDLE OF
THE WEEK. THE MORE POTENT WEATHER MAKER WILL BE A SIGNIFICANT COLD
FRONT THAT IS EXPECTED TO MOVE ACROSS THE AREA THURSDAY INTO
THURSDAY EVENING. THE FRONT WILL LIKELY BE SLOWED UP A BIT BY THE
HIGH TERRAIN OF EAST KENTUCKY FOR IT FINALLY EXITS THE AREA THURSDAY
EVENING. ONCE THE FRONT IS OUT OF THE AREA...A LARGE AND WELL
DEFINED AREA OF HIGH PRESSURE WILL MIGRATE SOUTHWARD OUT OF CANADA
AND THEN THE OHIO VALLEY...BEFORE FINALLY SETTLING OVER THE EASTERN
CONUS FROM FRIDAY ONWARD. THE AIR MASS ASSOCIATED WITH THIS RIDGE
WILL BRING VERY UNSEASONABLY COOL TEMPERATURES TO THE REGION FRIDAY
AND SATURDAY. HIGHS ON FRIDAY AND SATURDAY WILL ONLY BE TOPPING OUT
IN THE LOW TO MID 70S...BEFORE REBOUNDING A BIT ON SUNDAY...WHEN
HIGHS IN THE UPPER 70S TO AROUND 80 ARE EXPECTED. THE
GFS...ECMWF...AND NAEFS MODELS ALL BEGIN THE PERIOD WITH A LARGE
TROUGH OF LOW PRESSURE ALOFT ACROSS THE EASTERN CONUS...WITH A
STRONG RIDGE OF HIGH PRESSURE SETTING UP OUT WEST. THE MIDDLE OF THE
WEEK WILL FEATURE WARM AND WET WEATHER...WHILE THE END OF THE WEEK
AND THE UPCOMING WEEKEND WILL BE VERY COOL AND DRY AND FALL LIKE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 135 AM EDT TUE SEP 10 2013
VFR CONDITIONS WILL GIVE WAY TO MVFR/IFR FOG DEVELOPMENT IN THE
VALLEYS OVERNIGHT. SIMILAR TO THE LAST FEW NIGHTS...THIS FOG WILL
ONCE AGAIN IMPACT THE TAF SITES. WENT WITH SIMILAR FOG AS LAST NIGHT
IN THE TAFS SINCE CONDITIONS REMAIN VERY SIMILAR AND WOULD EXPECT
SIMILAR RESULTS. FOG WILL BURN OFF BY 13Z TOMORROW MORNING...LEAVING
BEHIND VFR CONDITIONS FOR THE REMAINDER OF THE DAY. AN ISOLATED
SHOWER OR THUNDERSTORM WILL BE POSSIBLE AGAIN...BUT NOT ENOUGH
CONFIDENCE TO INCLUDE IN THE FORECAST AT THIS TIME.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
528 AM EDT TUE SEP 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 527 AM EDT TUE SEP 10 2013
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...THE MID LEVEL LOW THAT
WAS OVER THE PACIFIC NW FOR SEVERAL DAYS IS NOW AN OPEN WAVE OVER
THE DAKOTAS INTO SRN MANITOBA. AT THE SFC...A LOW PRES TROF EXTENDS
FROM NW MN ACROSS LAKE SUPERIOR.
INITIALLY...WILL HAVE TO DEAL WITH SOME FOG EARLY THIS MORNING WHICH
WILL BE LOCALLY DENSE. WITH WESTERLY WINDS S OF THE SFC TROF
INCREASING A BIT OVER THE NEXT FEW HRS...FOG SHOULD CLEAR OUT OF THE
AREAS THAT SEE DOWNSLOPING WITH A W WIND. WHERE WINDS UPSLOPE...FOG
WILL DISSIPATE BY LATE MORNING UNDER A COMBINATION OF DAYTIME
HEATING AND MECHANICAL MIXING WITH INCREASING LOW-LEVEL WINDS. AS OF
09Z...KMQT RADAR DOES NOT SHOW ANY PCPN ACROSS THE FCST AREA.
HOWEVER...RIGHT ENTRANCE OF WSW TO ENE ORIENTED UPPER JET ASSOCIATED
WITH DAKOTAS/MANITOBA SHORTWAVE IS SUPPORTING A BKN BAND OF SHRA
FROM THE NEBRASKA TO NE MN. SOME OF THESE SHRA AND PERHAPS A TSRA
MAY AFFECT MAINLY WRN UPPER MI THIS MORNING AS UPPER JET TRANSLATES
EASTWARD. THIS AFTN...ATTENTION TURNS TO THE ERN FCST AREA AS
DAYTIME HEATING/LOW-LEVEL MOISTURE LEAD TO MLCAPE INCREASING TO
500-1000J/KG. WESTERLY LOW-LEVEL WINDS WILL LEAD TO ENHANCED
CONVERGENCE ACROSS INTERIOR ERN UPPER MI AS WINDS VEER NEAR LAKE
SUPERIOR AND BACK NEAR LAKE MICHIGAN AS LAKE BREEZE COMPONENT
DEVELOPS. EXPECT SCT SHRA/TSRA TO DEVELOP ROUGHLY ALONG A LINE
MIDWAY BTWN ESCANABA/MUNISING E TO NEWBERRY. ISOLATED SHRA/TSRA MAY
DEVELOP AS FAR W AS TOWARD KSAW/KIMT. AS FOR TEMPS...WITH INCREASING
W WINDS...DOWNSLOPE AREAS WILL SEE LOW CLOUDS CLEAR OUT THIS
MORNING. THIS WILL LIKELY LEAD TO A HOT/HUMID DAY OVER SCNTRL UPPER
MI AS DOWNSLOPING ENHANCES THE ALREADY VERY WARM START TO THE DAY.
MIXING TO 850-800MB ON NAM/GFS FCST SOUNDINGS SUGGESTS POTENTIAL FOR
MAX TEMPS INTO THE LOW/MID 90S OVER THE SCNTRL. SOME CLOUD COVER
THIS AFTN MAY LIMIT MIXING DEPTH...BUT DOWNSLOPING COULD STILL
SUPPORT TEMPS OVER 90F. FOR NOW...RAISED MAX TEMPS TO THE UPPER 80S
OVER THE SCNTRL WITH LOWER 80S EXTENDING INTO THE INTERIOR ERN FCST
AREA. ELSEWHERE...70S SHOULD BE THE RULE...THOUGH TEMPS MAY TOP 80F
WHERE W WINDS DOWNSLOPE.
AS UPPER JET CONTINUES TO TRANSLATE EASTWARD TONIGHT...RIGHT
ENTRANCE OF JET WILL AID A RIBBON OF LOW-MIDLEVEL FRONTOGENESIS
ACROSS THE UPPER LAKES. CONSENSUS OF MODEL GUIDANCE SHOWS THIS
FORCING SUPPORTING A BAND OF SHRA STREAKING ENE ACROSS WI TOWARD THE
STRAITS. THERE IS SOME UNCERTAINTY IN EXACTLY WHERE THIS RELATIVELY
NARROW BAND OF PCPN WILL BE LOCATED...BUT BULK OF GUIDANCE SUGGESTS
THE FAR SCNTRL/SE FCST AREA WILL BE CLIPPED. OPTED TO INCLUDE LOW
CHC POPS IN THAT AREA. SOME OF THE HIGHER RESOLUTION MODEL GUIDANCE
ALSO INDICATE LATE AFTN SHRA OVER NRN MN MAKING IT ACROSS LAKE
SUPERIOR AND AFFECTING WRN UPPER MI THIS EVENING. INCLUDED SCHC POPS
OVER THE W THIS EVENING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 525 AM EDT TUE SEP 10 2013
OUR ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH THURSDAY. WE WILL
FINALLY DISPLACE THE 500MB TROUGH THAT HAS BEEN BEEN SET UP ACROSS
THE NORTHERN TIER OF CENTRAL AND EASTERN U.S. FRIDAY NIGHT THROUGH
THE START OF THE UPCOMING WEEKEND...AS THE RIDGE MOVES OVERHEAD.
STARTING OUT AT 12Z WEDNESDAY...THE SFC LOW OVER N ONTARIO WILL BE
DRAGGING A COLD FRONT ACROSS MN AND FAR W LAKE SUPERIOR. MAINLY
AFTERNOON CONVECTION IS EXPECTED AS THE COLD FRONT DRAGS ACROSS THE
AREA...WITH THE ASSIST OF DAYTIME HEATING. ML CAPE VALUES TO OUT
AROUND 500J/KG OR LESS WEDNESDAY AFTERNOON OVER THE E HALF TO
TWO-THIRDS OF UPPER MI...AND QUICKLY DIMINISH TOWARD 00Z.
LARGE HIGH PRESSURE OVER S CENTRAL CANADA AND THE N PLAINS WEDNESDAY
NIGHT/THURSDAY MORNING WILL THEN BE THE MAIN INFLUENCE ON OUR
WEATHER FOR THE END OF THE WEEK. STRONG N WINDS /SLOWED DOWN APPROX
3-6HRS/ STILL LOOK REASONABLE...USHERING IN COLD AIR ACROSS LAKE
SUPERIOR AND UPPER MI.
THE COLDEST AIR OVERHEAD LOOKS TO BE SET UP AROUND 06Z FRIDAY...WITH
850MB TEMPS FALLING TO 1 TO -4C /COOLEST OFF THE ECMWF/. WHILE THERE
REMAINS THE POTENTIAL FOR FROST DEVELOPMENT...WITH THE COLD AIR
OVERHEAD AND PW VALUES FALLING TO AROUND 45 PERCENT OF NORMAL
/0.3-0.4IN/...N-NNE WINDS OFF LAKE SUPERIOR MAY STILL BE BRINGING
LOW CLOUDS AND EVEN LAKE ENHANCED RAIN SHOWERS/DRIZZLE ON N-NNE
WINDS OFF LAKE SUPERIOR.
AS FOR THE FROST POTENTIAL FOR FRIDAY NIGHT INTO SATURDAY
MORNING...WITH THE SFC HIGH SLIDING TO S CENTRAL AND EASTERN UPPER
MI...THE LIGHTEST WINDS WILL BE THERE. PW VALUES WILL NOT BE QUITE
AS LOW...IN THE 0.4-0.5 RANGE OR AROUND 50 PERCENT OF NORMAL. THESE
SLIGHTLY HIGHER PW VALUES AND 850MB TEMPS AROUND 5C WILL BE OFFSET
BY THE LIGHTER WINDS AND CLEAR SKY...WITH SIMILAR TEMP READINGS
EXPECTED ACROSS CENTRAL AREAS.
LOOK FOR A TEMPORARILY BREAK TO THE COOL WEATHER ON SATURDAY AND TO
A LESSER EXTENT SUNDAY...AS HIGHS TOP OUT IN THE 60S. THIS IS STILL
4-10F BELOW NORMAL FOR THIS TIME OF YEAR. WAA ON WSW WINDS SATURDAY
SHOULD ALLOW 850MB TEMPS TO RISE TO 8-10C. SUNDAY WILL BE A
DIFFERENT STORY...AS A SHORTWAVE LOOKS TO PUT AN END TO OUR DRY
WEATHER ON SUNDAY. SLOWED DOWN OUR INITIAL BLEND FOR THE EXTENDED
PERIOD...BUT LOOKING AT THE LATEST 10/00Z GFS/ECMWF RUNS. IN
FACT...THE SCATTERED POPS FOR SATURDAY NIGHT THROUGH SUNDAY LOOK TO
BE IN JEOPARDY IF THE 10/00Z GFS IS CORRECT...AS IT KEEPS US DRY
THROUGH AT LEAST NEXT MONDAY. WILL WAIT TO SEE HOW THE NEXT COUPLE
RUNS PLAY UP THIS FEATURE BEFORE MAKING TOO MANY CHANGES TO THE
ONGOING FCST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 125 AM EDT TUE SEP 10 2013
WITH ABUNDANT LOW LEVEL MOISTURE OVER THE AREA...VLIFR CONDITIONS
SHOULD PERSIST AT SAW/CMX OVERNIGHT INTO THE MORNING HRS. CONDITIONS
MAY BRIEFLY IMPROVE AT SAW AS SCT SHRA AND POSSIBLY A TSRA MOVE
THROUGH OVERNIGHT. MVFR CIGS AT IWD ARE ALSO EXPECTED TO GIVE WAY TO
IFR CIGS OVERNIGHT AS WINDS VEER LIGHT WRLY. ONLY GRADUAL
IMPROVEMENT IS EXPECTED BY MIDDAY WITH DAYTIME MIXING AND MODEST DRY
ADVECTION WITH INCREASING WRLY FLOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 318 AM EDT TUE SEP 10 2013
PATCHY TO AREAS OF FOG SHOULD SLOWLY DISSIPATE THIS MORNING. LOW
PRESSURE EXITING E LAKE SUPERIOR TODAY WILL BE REPLACED BY A BROAD
TROUGH THAT WILL BE EXTENDING SOUTHWARD FROM NORTHERN ONTARIO LATE
TONIGHT THROUGH EARLY WEDNESDAY EVENING. A LARGE HIGH PRESSURE
ENCOMPASSING MUCH OF S CENTRAL CANADA AND THE N PLAINS WEDNESDAY
NIGHT WILL SLOWLY DRIFT ACROSS THE UPPER GREAT LAKES FRIDAY INTO
SATURDAY...BEFORE EXITING TO THE LOWER GREAT LAKES AND THE E COAST
FOR THE LATTER HALF OF THE WEEKEND. THE STRONGEST WINDS OVER LAKE
SUPERIOR...OUTSIDE OF THUNDERSTORMS...WILL BE THURSDAY MORNING
THROUGH EARLY FRIDAY MORNING...WITH NW GUSTS OF 20-30KTS CENTERED
ACROSS MAINLY CENTRAL AND E LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...JLB
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
526 AM EDT TUE SEP 10 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 419 PM EDT MON SEP 9 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A MID LEVEL LOW OVER NE
MT. LOW IS WEAKENING/OPENING UP ON WATER VAPOR LOOP/ANALYSIS AND IS
FCST TO MOVE E THROUGH THE NRN PLAINS STATES TONIGHT. ASSOC SFC LOW
NOW OVER SW MN IS IN TURN FCST TO LIFT NE ACROSS THE FCST AREA
TONIGHT WITH APPROACH OF NRN PLAINS SHORTWAVE. STRONG WAA/ISENTROPIC
LIFT AHEAD OF FRONTAL BOUNDARY AS IT LIFTS FM SRN WI TOWARD SCNTRL
UPR MI THIS EVENING WILL PROVIDE FOCUS FOR ANOTHER ROUND OF
CONVECTION TONIGHT WITH THE POTENTIAL FOR STRONG TO POSSIBLY SVR
STORMS.
TONIGHT...BIGGEST THING GOING AGAINST SVR WX TONIGHT WILL BE LACK OF
SFC-BASED INSTABILITY FM TODAY DUE TO THICK CLOUDS PERSISTING OVER
THE AREA FM EARLIER MCS OVER THE NRN PLAINS. EVEN SO...COMBINATION
OF STRENGTHING LOW-LVL JET...INCREASING WAA/ISENTROPIC LIFT AND
ADVANCE OF WARM FRONTAL BOUNDARY TOWARD SCNTRL FCST AREA WILL ALLOW
FOR INCREASING ELEVATED INSTABILITY (NAM AND RUC SHOW ELEVATED CAPES
IN EXCESS OF 2000 J/KG THIS EVENING) AND DEEP LAYER SHEAR TO 45-50
KT WHICH COULD BRING POTENTIAL FOR STRONG TO POSSIBLY SVR
STORMS...WITH THE BEST THREAT FOR SVR OVER SCNTRL MI AND SE UPR MI
IN CLOSER PROXIMITY TO ADVANCING WARM FRONT. GIVEN LACK OF SFC-BASED
INSTABILITY...THERE MAY BE MORE OF A THREAT OF ELEVATED STORMS WITH
LARGE HAIL PERHAPS BEING THE BIGGER THREAT FOR OUR AREA. WILL
CONTINUE TO MENTION STRONG TO SEVERE STORMS IN THE HWO WITH THE BEST
THREAT OF HEAVY RAINFALL ACROSS NRN UPR MI AND THE KEWEENAW
PENINSULA. MODEL QPF STILL SUGGESTS THE KEWEENAW PENINSULA AND ERN
UPR MI WILL HAVE BEST CHC FOR HEAVY RAINFALL TONIGHT. LOOK FOR A
GENERAL DIMINISHING TREND IN CONVECTION OVERNIGHT (AFT 06Z) AS
LOW-LVL JET VEERS FM SW TO A MORE WRLY DIRECTION.
DENSE FOG HAS BEEN OBSERVED OVER THE KEWEENAW PENINSULA AND LAKE
SUPERIOR THIS AFTERNOON AND WOULD EXPECT FOG TO CONTINUE INTO THIS
EVENING WITH SHRA MOVING OVER THE AREA AND ONSHORE E-SE FLOW
PERSISTING. EXPECT PATCHY FOG TO MOVE ONSHORE TO NRN ZONES LATE
TONIGHT AS WIND SHIFTS N-NW BEHIND SFC TROUGH.
TUESDAY...THERE COULD BE SOME LINGERING UPSLOPE DZ IN THE MORNING
OVER NRN ZONES AS LOW-LVLS REMAIN MOIST. SOME ISOLD SHRA ARE ALSO
POSSIBLE MAINLY OVER SCNTRL AND ERN SECTIONS OF THE CWA UNTIL
LINGERING SFC BOUNDARY SAGS SE OF THE AREA LATE IN THE DAY.
PERSISTENT CLOUDS OVER THE AREA WILL RESULT IN HIGH TEMPS RANGING
FROM THE 60S NEAR LAKE SUPERIOR IN ONSHORE FLOW TO THE MID 70S
SCNTRL AND EAST ALONG FRONTAL BOUNDARY.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 525 AM EDT TUE SEP 10 2013
OUR ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH THURSDAY. WE WILL
FINALLY DISPLACE THE 500MB TROUGH THAT HAS BEEN BEEN SET UP ACROSS
THE NORTHERN TIER OF CENTRAL AND EASTERN U.S. FRIDAY NIGHT THROUGH
THE START OF THE UPCOMING WEEKEND...AS THE RIDGE MOVES OVERHEAD.
STARTING OUT AT 12Z WEDNESDAY...THE SFC LOW OVER N ONTARIO WILL BE
DRAGGING A COLD FRONT ACROSS MN AND FAR W LAKE SUPERIOR. MAINLY
AFTERNOON CONVECTION IS EXPECTED AS THE COLD FRONT DRAGS ACROSS THE
AREA...WITH THE ASSIST OF DAYTIME HEATING. ML CAPE VALUES TO OUT
AROUND 500J/KG OR LESS WEDNESDAY AFTERNOON OVER THE E HALF TO
TWO-THIRDS OF UPPER MI...AND QUICKLY DIMINISH TOWARD 00Z.
LARGE HIGH PRESSURE OVER S CENTRAL CANADA AND THE N PLAINS WEDNESDAY
NIGHT/THURSDAY MORNING WILL THEN BE THE MAIN INFLUENCE ON OUR
WEATHER FOR THE END OF THE WEEK. STRONG N WINDS /SLOWED DOWN APPROX
3-6HRS/ STILL LOOK REASONABLE...USHERING IN COLD AIR ACROSS LAKE
SUPERIOR AND UPPER MI.
THE COLDEST AIR OVERHEAD LOOKS TO BE SET UP AROUND 06Z FRIDAY...WITH
850MB TEMPS FALLING TO 1 TO -4C /COOLEST OFF THE ECMWF/. WHILE THERE
REMAINS THE POTENTIAL FOR FROST DEVELOPMENT...WITH THE COLD AIR
OVERHEAD AND PW VALUES FALLING TO AROUND 45 PERCENT OF NORMAL
/0.3-0.4IN/...N-NNE WINDS OFF LAKE SUPERIOR MAY STILL BE BRINGING
LOW CLOUDS AND EVEN LAKE ENHANCED RAIN SHOWERS/DRIZZLE ON N-NNE
WINDS OFF LAKE SUPERIOR.
AS FOR THE FROST POTENTIAL FOR FRIDAY NIGHT INTO SATURDAY
MORNING...WITH THE SFC HIGH SLIDING TO S CENTRAL AND EASTERN UPPER
MI...THE LIGHTEST WINDS WILL BE THERE. PW VALUES WILL NOT BE QUITE
AS LOW...IN THE 0.4-0.5 RANGE OR AROUND 50 PERCENT OF NORMAL. THESE
SLIGHTLY HIGHER PW VALUES AND 850MB TEMPS AROUND 5C WILL BE OFFSET
BY THE LIGHTER WINDS AND CLEAR SKY...WITH SIMILAR TEMP READINGS
EXPECTED ACROSS CENTRAL AREAS.
LOOK FOR A TEMPORARILY BREAK TO THE COOL WEATHER ON SATURDAY AND TO
A LESSER EXTENT SUNDAY...AS HIGHS TOP OUT IN THE 60S. THIS IS STILL
4-10F BELOW NORMAL FOR THIS TIME OF YEAR. WAA ON WSW WINDS SATURDAY
SHOULD ALLOW 850MB TEMPS TO RISE TO 8-10C. SUNDAY WILL BE A
DIFFERENT STORY...AS A SHORTWAVE LOOKS TO PUT AN END TO OUR DRY
WEATHER ON SUNDAY. SLOWED DOWN OUR INITIAL BLEND FOR THE EXTENDED
PERIOD...BUT LOOKING AT THE LATEST 10/00Z GFS/ECMWF RUNS. IN
FACT...THE SCATTERED POPS FOR SATURDAY NIGHT THROUGH SUNDAY LOOK TO
BE IN JEOPARDY IF THE 10/00Z GFS IS CORRECT...AS IT KEEPS US DRY
THROUGH AT LEAST NEXT MONDAY. WILL WAIT TO SEE HOW THE NEXT COUPLE
RUNS PLAY UP THIS FEATURE BEFORE MAKING TOO MANY CHANGES TO THE
ONGOING FCST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 125 AM EDT TUE SEP 10 2013
WITH ABUNDANT LOW LEVEL MOISTURE OVER THE AREA...VLIFR CONDITIONS
SHOULD PERSIST AT SAW/CMX OVERNIGHT INTO THE MORNING HRS. CONDITIONS
MAY BRIEFLY IMPROVE AT SAW AS SCT SHRA AND POSSIBLY A TSRA MOVE
THROUGH OVERNIGHT. MVFR CIGS AT IWD ARE ALSO EXPECTED TO GIVE WAY TO
IFR CIGS OVERNIGHT AS WINDS VEER LIGHT WRLY. ONLY GRADUAL
IMPROVEMENT IS EXPECTED BY MIDDAY WITH DAYTIME MIXING AND MODEST DRY
ADVECTION WITH INCREASING WRLY FLOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 318 AM EDT TUE SEP 10 2013
PATCHY TO AREAS OF FOG SHOULD SLOWLY DISSIPATE THIS MORNING. LOW
PRESSURE EXITING E LAKE SUPERIOR TODAY WILL BE REPLACED BY A BROAD
TROUGH THAT WILL BE EXTENDING SOUTHWARD FROM NORTHERN ONTARIO LATE
TONIGHT THROUGH EARLY WEDNESDAY EVENING. A LARGE HIGH PRESSURE
ENCOMPASSING MUCH OF S CENTRAL CANADA AND THE N PLAINS WEDNESDAY
NIGHT WILL SLOWLY DRIFT ACROSS THE UPPER GREAT LAKES FRIDAY INTO
SATURDAY...BEFORE EXITING TO THE LOWER GREAT LAKES AND THE E COAST
FOR THE LATTER HALF OF THE WEEKEND. THE STRONGEST WINDS OVER LAKE
SUPERIOR...OUTSIDE OF THUNDERSTORMS...WILL BE THURSDAY MORNING
THROUGH EARLY FRIDAY MORNING...WITH NW GUSTS OF 20-30KTS CENTERED
ACROSS MAINLY CENTRAL AND E LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...JLB
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
318 AM EDT TUE SEP 10 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 419 PM EDT MON SEP 9 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A MID LEVEL LOW OVER NE
MT. LOW IS WEAKENING/OPENING UP ON WATER VAPOR LOOP/ANALYSIS AND IS
FCST TO MOVE E THROUGH THE NRN PLAINS STATES TONIGHT. ASSOC SFC LOW
NOW OVER SW MN IS IN TURN FCST TO LIFT NE ACROSS THE FCST AREA
TONIGHT WITH APPROACH OF NRN PLAINS SHORTWAVE. STRONG WAA/ISENTROPIC
LIFT AHEAD OF FRONTAL BOUNDARY AS IT LIFTS FM SRN WI TOWARD SCNTRL
UPR MI THIS EVENING WILL PROVIDE FOCUS FOR ANOTHER ROUND OF
CONVECTION TONIGHT WITH THE POTENTIAL FOR STRONG TO POSSIBLY SVR
STORMS.
TONIGHT...BIGGEST THING GOING AGAINST SVR WX TONIGHT WILL BE LACK OF
SFC-BASED INSTABILITY FM TODAY DUE TO THICK CLOUDS PERSISTING OVER
THE AREA FM EARLIER MCS OVER THE NRN PLAINS. EVEN SO...COMBINATION
OF STRENGTHING LOW-LVL JET...INCREASING WAA/ISENTROPIC LIFT AND
ADVANCE OF WARM FRONTAL BOUNDARY TOWARD SCNTRL FCST AREA WILL ALLOW
FOR INCREASING ELEVATED INSTABILITY (NAM AND RUC SHOW ELEVATED CAPES
IN EXCESS OF 2000 J/KG THIS EVENING) AND DEEP LAYER SHEAR TO 45-50
KT WHICH COULD BRING POTENTIAL FOR STRONG TO POSSIBLY SVR
STORMS...WITH THE BEST THREAT FOR SVR OVER SCNTRL MI AND SE UPR MI
IN CLOSER PROXIMITY TO ADVANCING WARM FRONT. GIVEN LACK OF SFC-BASED
INSTABILITY...THERE MAY BE MORE OF A THREAT OF ELEVATED STORMS WITH
LARGE HAIL PERHAPS BEING THE BIGGER THREAT FOR OUR AREA. WILL
CONTINUE TO MENTION STRONG TO SEVERE STORMS IN THE HWO WITH THE BEST
THREAT OF HEAVY RAINFALL ACROSS NRN UPR MI AND THE KEWEENAW
PENINSULA. MODEL QPF STILL SUGGESTS THE KEWEENAW PENINSULA AND ERN
UPR MI WILL HAVE BEST CHC FOR HEAVY RAINFALL TONIGHT. LOOK FOR A
GENERAL DIMINISHING TREND IN CONVECTION OVERNIGHT (AFT 06Z) AS
LOW-LVL JET VEERS FM SW TO A MORE WRLY DIRECTION.
DENSE FOG HAS BEEN OBSERVED OVER THE KEWEENAW PENINSULA AND LAKE
SUPERIOR THIS AFTERNOON AND WOULD EXPECT FOG TO CONTINUE INTO THIS
EVENING WITH SHRA MOVING OVER THE AREA AND ONSHORE E-SE FLOW
PERSISTING. EXPECT PATCHY FOG TO MOVE ONSHORE TO NRN ZONES LATE
TONIGHT AS WIND SHIFTS N-NW BEHIND SFC TROUGH.
TUESDAY...THERE COULD BE SOME LINGERING UPSLOPE DZ IN THE MORNING
OVER NRN ZONES AS LOW-LVLS REMAIN MOIST. SOME ISOLD SHRA ARE ALSO
POSSIBLE MAINLY OVER SCNTRL AND ERN SECTIONS OF THE CWA UNTIL
LINGERING SFC BOUNDARY SAGS SE OF THE AREA LATE IN THE DAY.
PERSISTENT CLOUDS OVER THE AREA WILL RESULT IN HIGH TEMPS RANGING
FROM THE 60S NEAR LAKE SUPERIOR IN ONSHORE FLOW TO THE MID 70S
SCNTRL AND EAST ALONG FRONTAL BOUNDARY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 419 PM EDT MON SEP 9 2013
A WEAK HIGH PRESSURE RIDGE WILL SLIDE OVER THE AREA ON TUESDAY
NIGHT BEHIND THE EXITING LOW PRESSURE SYSTEM. WITH THE AREA STILL
UNDER THE RIGHT REAR OF THE UPPER JET...A WEAK SHORTWAVE MOVING
THROUGH...AND SOME LINGERING MOISTURE...OPTED TO LINGER A FEW
ISOLATED SHOWERS NEAR LAKE MICHIGAN FOR THE FIRST PART OF THE
EVENING.
ATTENTION THEN TURNS TO THE SHORTWAVE THAT IS CURRENTLY IN THE
WESTERN PART OF THE NORTHWEST TERRITORIES. THIS SHORTWAVE WILL DIVE
SOUTHEAST TO LAKE WINNIPEG BY 12Z WEDNESDAY AND THEN THROUGH THE
UPPER GREAT LAKES WEDNESDAY NIGHT AND CONTINUE TO INFLUENCE THE
WEATHER INTO THURSDAY. A LOW PRESSURE SYSTEM ASSOCIATED WITH THIS
SHORTWAVE WILL TRACK ACROSS NORTHERN ONTARIO AND SWEEP THE MAIN COLD
FRONT ACROSS THE CWA LATE WEDNESDAY MORNING AND INTO THE AFTERNOON.
A WEAK TROUGH WILL TRY TO SLIDE ACROSS THE AREA LATE TUESDAY
NIGHT...WHICH COULD PRODUCE A FEW SHOWERS. BUT THE BEST CHANCE WILL
BE IN THE AFTERNOON WITH THE MAIN FRONT AND ASSISTANCE FROM DIURNAL
HEATING. THE MAIN INHIBITING FACTOR FOR MORE WIDESPREAD SHOWERS IS
THE SPLOTCHY NATURE OF THE DEEPER MOISTURE IN THE MODELS.
THUS...WILL GO FOR MORE LOW END CHANCES...WITH THE HIGHEST OVER THE
EAST BASED OFF THE TIMING OF THE FRONT WITH PEAK HEATING. DID CAP
THUNDER MENTION AT SLIGHT CHANCES...DUE TO THE WIDE VARIETY OF
MLCAPE VALUES IN THE MODELS (RANGING FROM 200-700 J/KG).
THURSDAY WILL BE COOL AND BREEZY ACROSS THE AREA WITH THE TIGHT
PRESSURE GRADIENT AS HIGH PRESSURE BUILDS INTO THE NORTHERN PLAINS.
850MB TEMPS WILL FALL FROM AROUND 11C ON WEDNESDAY TO 0-2C BY 00Z
THURSDAY. THE COOL TEMPERATURES OVER THE WARM LAKE WATERS WILL
COMBINE WITH THE LOW LEVEL MOISTURE SHOWN ON BOTH ECMWF/GFS FOR
LAKE INDUCED CLOUDS AND PROBABLY A FEW SHOWERS OVER THE LOCATIONS
FAVORED BY NORTH-NORTHWEST WINDS. EXPECT THE STRONGEST WIND GUSTS
TO BE OVER THE EASTERN CWA...WHERE WINDS WILL BE GUSTING TO
30MPH. WITH TEMPERATURES IN THE UPPER 50S AND LOWER 60S...THE
CLOUDS/WINDS/SHOWERS WILL LEAD TO A VERY OCTOBER LIKE DAY FOR MID
SEPTEMBER.
THE HIGH WILL BUILD SOUTHEAST ON THURSDAY NIGHT AND BE CENTERED
OVER THE AREA FOR FRIDAY AFTERNOON AND EVENING. THE DRY AIR
ASSOCIATED WITH THE HIGH WILL DIMINISH THE CLOUDS...BUT ALSO BRING
THE POTENTIAL FOR FROST OVER THE INTERIOR LOCATIONS THURSDAY NIGHT
AND FRIDAY NIGHT. CONFIDENCE IS FAIRLY LOW FOR THURSDAY NIGHT...AS
IT WILL DEPEND ON THE TIMING OF THE EXITING CLOUDS AND ALSO THE
WINDS WEAKENING UP FOR DECENT RADIATIONAL COOLING. THINK THE WESTERN
CWA WILL HAVE THE BEST CHANCE ON THURSDAY NIGHT AND WILL CONTINUE
THE COOLEST TEMPS THERE. THE CENTRAL AND EAST WILL HAVE THE BEST
SHOT FOR FROST ON FRIDAY NIGHT...SINCE THEY WILL BE THE CLOSEST TO
THE HIGH CENTER WITH THE LIGHTER WINDS. OVER THE FAR
WEST...SOUTHERLY RETURN FLOW ON THE BACK SIDE OF THE HIGH ON
FRIDAY NIGHT PRODUCES A LITTLE MORE UNCERTAINTY ON HOW COLD THE
TEMPS WILL GET BEFORE WINDS BEGIN TO PICK UP.
UPPER RIDGE WILL MOVE INTO THE AREA FOR SATURDAY AND BRING
TEMPERATURES BACK UP TOWARDS THE MID-UPPER 60S. THE NEXT SYSTEM
LOOKS TO AFFECT THE AREA ON SATURDAY NIGHT INTO SUNDAY. THIS
SHORTWAVE AND SURFACE LOW LOOK TO TAKE A SIMILAR TRACK TO THE ONE
THIS WEDNESDAY...ALTHOUGH THERE APPEARS TO BE A BETTER OPPORTUNITY
FOR RETURN FLOW TO PROVIDE MORE MOISTURE FOR SHOWERS AS THE FRONT
MOVES THROUGH. INSTABILITY AND MID-LEVEL LAPSE RATES ARE VERY
WEAK...SO HAVE LEFT THE MENTION OF THUNDER OUT OF THE FORECAST.
ONCE AGAIN...HIGH PRESSURE AND COOLER 850MB TEMPS WILL MOVE IN FOR
SUNDAY AFTERNOON INTO MONDAY...BRINGING ANOTHER BELOW NORMAL
TEMPERATURE DAY FOR MONDAY. GFS/ECMWF DO DIFFER ON THE AMOUNT OF
LOW LEVEL MOISTURE PRESENT FOR SUNDAY NIGHT INTO MONDAY...BUT WITH
THE COLD TEMPERATURES ALOFT IT SHOULDN/T TAKE MUCH TO KICK OF LAKE
CLOUDS OR EVEN SOME SHOWERS (AT LEAST FOR SUNDAY NIGHT).
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 125 AM EDT TUE SEP 10 2013
WITH ABUNDANT LOW LEVEL MOISTURE OVER THE AREA...VLIFR CONDITIONS
SHOULD PERSIST AT SAW/CMX OVERNIGHT INTO THE MORNING HRS. CONDITIONS
MAY BRIEFLY IMPROVE AT SAW AS SCT SHRA AND POSSIBLY A TSRA MOVE
THROUGH OVERNIGHT. MVFR CIGS AT IWD ARE ALSO EXPECTED TO GIVE WAY TO
IFR CIGS OVERNIGHT AS WINDS VEER LIGHT WRLY. ONLY GRADUAL
IMPROVEMENT IS EXPECTED BY MIDDAY WITH DAYTIME MIXING AND MODEST DRY
ADVECTION WITH INCREASING WRLY FLOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 318 AM EDT TUE SEP 10 2013
PATCHY TO AREAS OF FOG SHOULD SLOWLY DISSIPATE THIS MORNING. LOW
PRESSURE EXITING E LAKE SUPERIOR TODAY WILL BE REPLACED BY A BROAD
TROUGH THAT WILL BE EXTENDING SOUTHWARD FROM NORTHERN ONTARIO LATE
TONIGHT THROUGH EARLY WEDNESDAY EVENING. A LARGE HIGH PRESSURE
ENCOMPASING MUCH OF S CENTRAL CANADA AND THE N PLAINS WEDNESDAY
NIGHT WILL SLOWLY DRIFT ACROSS THE UPPER GREAT LAKES FRIDAY INTO
SATURDAY...BEFORE EXITING TO THE LOWER GREAT LAKES AND THE E COAST
FOR THE LATTER HALF OF THE WEEKEND. THE STRONGEST WINDS OVER LAKE
SUPERIOR...OUTSIDE OF THUNDERSTORMS...WILL BE THURSDAY MORNING
THROUGH EARLY FRIDAY MORNING...WITH NW GUSTS OF 20-30KTS CENTERED
ACROSS MAINLY CENTRAL AND E LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...JLB
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
127 AM EDT TUE SEP 10 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 419 PM EDT MON SEP 9 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A MID LEVEL LOW OVER NE
MT. LOW IS WEAKENING/OPENING UP ON WATER VAPOR LOOP/ANALYSIS AND IS
FCST TO MOVE E THROUGH THE NRN PLAINS STATES TONIGHT. ASSOC SFC LOW
NOW OVER SW MN IS IN TURN FCST TO LIFT NE ACROSS THE FCST AREA
TONIGHT WITH APPROACH OF NRN PLAINS SHORTWAVE. STRONG WAA/ISENTROPIC
LIFT AHEAD OF FRONTAL BOUNDARY AS IT LIFTS FM SRN WI TOWARD SCNTRL
UPR MI THIS EVENING WILL PROVIDE FOCUS FOR ANOTHER ROUND OF
CONVECTION TONIGHT WITH THE POTENTIAL FOR STRONG TO POSSIBLY SVR
STORMS.
TONIGHT...BIGGEST THING GOING AGAINST SVR WX TONIGHT WILL BE LACK OF
SFC-BASED INSTABILITY FM TODAY DUE TO THICK CLOUDS PERSISTING OVER
THE AREA FM EARLIER MCS OVER THE NRN PLAINS. EVEN SO...COMBINATION
OF STRENGTHING LOW-LVL JET...INCREASING WAA/ISENTROPIC LIFT AND
ADVANCE OF WARM FRONTAL BOUNDARY TOWARD SCNTRL FCST AREA WILL ALLOW
FOR INCREASING ELEVATED INSTABILITY (NAM AND RUC SHOW ELEVATED CAPES
IN EXCESS OF 2000 J/KG THIS EVENING) AND DEEP LAYER SHEAR TO 45-50
KT WHICH COULD BRING POTENTIAL FOR STRONG TO POSSIBLY SVR
STORMS...WITH THE BEST THREAT FOR SVR OVER SCNTRL MI AND SE UPR MI
IN CLOSER PROXIMITY TO ADVANCING WARM FRONT. GIVEN LACK OF SFC-BASED
INSTABILITY...THERE MAY BE MORE OF A THREAT OF ELEVATED STORMS WITH
LARGE HAIL PERHAPS BEING THE BIGGER THREAT FOR OUR AREA. WILL
CONTINUE TO MENTION STRONG TO SEVERE STORMS IN THE HWO WITH THE BEST
THREAT OF HEAVY RAINFALL ACROSS NRN UPR MI AND THE KEWEENAW
PENINSULA. MODEL QPF STILL SUGGESTS THE KEWEENAW PENINSULA AND ERN
UPR MI WILL HAVE BEST CHC FOR HEAVY RAINFALL TONIGHT. LOOK FOR A
GENERAL DIMINISHING TREND IN CONVECTION OVERNIGHT (AFT 06Z) AS
LOW-LVL JET VEERS FM SW TO A MORE WRLY DIRECTION.
DENSE FOG HAS BEEN OBSERVED OVER THE KEWEENAW PENINSULA AND LAKE
SUPERIOR THIS AFTERNOON AND WOULD EXPECT FOG TO CONTINUE INTO THIS
EVENING WITH SHRA MOVING OVER THE AREA AND ONSHORE E-SE FLOW
PERSISTING. EXPECT PATCHY FOG TO MOVE ONSHORE TO NRN ZONES LATE
TONIGHT AS WIND SHIFTS N-NW BEHIND SFC TROUGH.
TUESDAY...THERE COULD BE SOME LINGERING UPSLOPE DZ IN THE MORNING
OVER NRN ZONES AS LOW-LVLS REMAIN MOIST. SOME ISOLD SHRA ARE ALSO
POSSIBLE MAINLY OVER SCNTRL AND ERN SECTIONS OF THE CWA UNTIL
LINGERING SFC BOUNDARY SAGS SE OF THE AREA LATE IN THE DAY.
PERSISTENT CLOUDS OVER THE AREA WILL RESULT IN HIGH TEMPS RANGING
FROM THE 60S NEAR LAKE SUPERIOR IN ONSHORE FLOW TO THE MID 70S
SCNTRL AND EAST ALONG FRONTAL BOUNDARY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 419 PM EDT MON SEP 9 2013
A WEAK HIGH PRESSURE RIDGE WILL SLIDE OVER THE AREA ON TUESDAY
NIGHT BEHIND THE EXITING LOW PRESSURE SYSTEM. WITH THE AREA STILL
UNDER THE RIGHT REAR OF THE UPPER JET...A WEAK SHORTWAVE MOVING
THROUGH...AND SOME LINGERING MOISTURE...OPTED TO LINGER A FEW
ISOLATED SHOWERS NEAR LAKE MICHIGAN FOR THE FIRST PART OF THE
EVENING.
ATTENTION THEN TURNS TO THE SHORTWAVE THAT IS CURRENTLY IN THE
WESTERN PART OF THE NORTHWEST TERRITORIES. THIS SHORTWAVE WILL DIVE
SOUTHEAST TO LAKE WINNIPEG BY 12Z WEDNESDAY AND THEN THROUGH THE
UPPER GREAT LAKES WEDNESDAY NIGHT AND CONTINUE TO INFLUENCE THE
WEATHER INTO THURSDAY. A LOW PRESSURE SYSTEM ASSOCIATED WITH THIS
SHORTWAVE WILL TRACK ACROSS NORTHERN ONTARIO AND SWEEP THE MAIN COLD
FRONT ACROSS THE CWA LATE WEDNESDAY MORNING AND INTO THE AFTERNOON.
A WEAK TROUGH WILL TRY TO SLIDE ACROSS THE AREA LATE TUESDAY
NIGHT...WHICH COULD PRODUCE A FEW SHOWERS. BUT THE BEST CHANCE WILL
BE IN THE AFTERNOON WITH THE MAIN FRONT AND ASSISTANCE FROM DIURNAL
HEATING. THE MAIN INHIBITING FACTOR FOR MORE WIDESPREAD SHOWERS IS
THE SPLOTCHY NATURE OF THE DEEPER MOISTURE IN THE MODELS.
THUS...WILL GO FOR MORE LOW END CHANCES...WITH THE HIGHEST OVER THE
EAST BASED OFF THE TIMING OF THE FRONT WITH PEAK HEATING. DID CAP
THUNDER MENTION AT SLIGHT CHANCES...DUE TO THE WIDE VARIETY OF
MLCAPE VALUES IN THE MODELS (RANGING FROM 200-700 J/KG).
THURSDAY WILL BE COOL AND BREEZY ACROSS THE AREA WITH THE TIGHT
PRESSURE GRADIENT AS HIGH PRESSURE BUILDS INTO THE NORTHERN PLAINS.
850MB TEMPS WILL FALL FROM AROUND 11C ON WEDNESDAY TO 0-2C BY 00Z
THURSDAY. THE COOL TEMPERATURES OVER THE WARM LAKE WATERS WILL
COMBINE WITH THE LOW LEVEL MOISTURE SHOWN ON BOTH ECMWF/GFS FOR
LAKE INDUCED CLOUDS AND PROBABLY A FEW SHOWERS OVER THE LOCATIONS
FAVORED BY NORTH-NORTHWEST WINDS. EXPECT THE STRONGEST WIND GUSTS
TO BE OVER THE EASTERN CWA...WHERE WINDS WILL BE GUSTING TO
30MPH. WITH TEMPERATURES IN THE UPPER 50S AND LOWER 60S...THE
CLOUDS/WINDS/SHOWERS WILL LEAD TO A VERY OCTOBER LIKE DAY FOR MID
SEPTEMBER.
THE HIGH WILL BUILD SOUTHEAST ON THURSDAY NIGHT AND BE CENTERED
OVER THE AREA FOR FRIDAY AFTERNOON AND EVENING. THE DRY AIR
ASSOCIATED WITH THE HIGH WILL DIMINISH THE CLOUDS...BUT ALSO BRING
THE POTENTIAL FOR FROST OVER THE INTERIOR LOCATIONS THURSDAY NIGHT
AND FRIDAY NIGHT. CONFIDENCE IS FAIRLY LOW FOR THURSDAY NIGHT...AS
IT WILL DEPEND ON THE TIMING OF THE EXITING CLOUDS AND ALSO THE
WINDS WEAKENING UP FOR DECENT RADIATIONAL COOLING. THINK THE WESTERN
CWA WILL HAVE THE BEST CHANCE ON THURSDAY NIGHT AND WILL CONTINUE
THE COOLEST TEMPS THERE. THE CENTRAL AND EAST WILL HAVE THE BEST
SHOT FOR FROST ON FRIDAY NIGHT...SINCE THEY WILL BE THE CLOSEST TO
THE HIGH CENTER WITH THE LIGHTER WINDS. OVER THE FAR
WEST...SOUTHERLY RETURN FLOW ON THE BACK SIDE OF THE HIGH ON
FRIDAY NIGHT PRODUCES A LITTLE MORE UNCERTAINTY ON HOW COLD THE
TEMPS WILL GET BEFORE WINDS BEGIN TO PICK UP.
UPPER RIDGE WILL MOVE INTO THE AREA FOR SATURDAY AND BRING
TEMPERATURES BACK UP TOWARDS THE MID-UPPER 60S. THE NEXT SYSTEM
LOOKS TO AFFECT THE AREA ON SATURDAY NIGHT INTO SUNDAY. THIS
SHORTWAVE AND SURFACE LOW LOOK TO TAKE A SIMILAR TRACK TO THE ONE
THIS WEDNESDAY...ALTHOUGH THERE APPEARS TO BE A BETTER OPPORTUNITY
FOR RETURN FLOW TO PROVIDE MORE MOISTURE FOR SHOWERS AS THE FRONT
MOVES THROUGH. INSTABILITY AND MID-LEVEL LAPSE RATES ARE VERY
WEAK...SO HAVE LEFT THE MENTION OF THUNDER OUT OF THE FORECAST.
ONCE AGAIN...HIGH PRESSURE AND COOLER 850MB TEMPS WILL MOVE IN FOR
SUNDAY AFTERNOON INTO MONDAY...BRINGING ANOTHER BELOW NORMAL
TEMPERATURE DAY FOR MONDAY. GFS/ECMWF DO DIFFER ON THE AMOUNT OF
LOW LEVEL MOISTURE PRESENT FOR SUNDAY NIGHT INTO MONDAY...BUT WITH
THE COLD TEMPERATURES ALOFT IT SHOULDN/T TAKE MUCH TO KICK OF LAKE
CLOUDS OR EVEN SOME SHOWERS (AT LEAST FOR SUNDAY NIGHT).
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 125 AM EDT TUE SEP 10 2013
WITH ABUNDANT LOW LEVEL MOISTURE OVER THE AREA...VLIFR CONDITIONS
SHOULD PERSIST AT SAW/CMX OVERNIGHT INTO THE MORNING HRS. CONDITIONS
MAY BRIEFLY IMPROVE AT SAW AS SCT SHRA AND POSSIBLY A TSRA MOVE
THROUGH OVERNIGHT. MVFR CIGS AT IWD ARE ALSO EXPECTED TO GIVE WAY TO
IFR CIGS OVERNIGHT AS WINDS VEER LIGHT WRLY. ONLY GRADUAL
IMPROVEMENT IS EXPECTED BY MIDDAY WITH DAYTIME MIXING AND MODEST DRY
ADVECTION WITH INCREASING WRLY FLOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EDT MON SEP 9 2013
LOW PRESSURE OVER NORTHEAST SD WILL LIFT INTO CENTRAL AND ERN UPR MI
TONIGHT AND THEN INTO FAR SE ONTARIO ON TUESDAY. NE WINDS FUNNELING
DOWN THE WRN PORTION OF LAKE SUPERIOR COULD GUST OVER 20 KT THIS
EVENING ON THE BACKSIDE OF THE LOW. A BRIEF RIDGE WILL MOVE OVER
LAKE SUPERIOR TUESDAY AFTERNOON THROUGH TUESDAY NIGHT...OUT AHEAD OF
A WEAK TROUGH EXTENDING FROM NORTHERN ONTARIO DURING THE DAY
WEDNESDAY. LARGE HIGH PRESSURE OVER SOUTH CENTRAL CANADA WEDNESDAY
NIGHT WILL SLOWLY SINK ACROSS GREAT LAKES...WHERE IT WILL REMAIN
FROM THURSDAY NIGHT THROUGH FRIDAY NIGHT. NW WINDS WILL LIKELY GUST
20-30KTS LATE WEDNESDAY NIGHT THROUGH LATE THURSDAY NIGHT AS HIGH
PRESSURE SINKS IN FROM THE NNW. OTHERWISE WITH HIGH PRESSURE
OVERHEAD...LIGHT WINDS LESS THAN 20KTS ARE EXPECTED BY FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
358 AM CDT TUE SEP 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT TUE SEP 10 2013
A RATHER CONVOLUTED SURFACE/UPPER AIR PATTERN OVER THE REGION THIS
MORNING. CENTERS OF LOW PRESSURE WERE NOTED OVER NORTHERN WI...
NORTHERN MN AND ND. A LEAD COLD FRONT MEANDERED FROM NORTHERN WI
THROUGH SE MN AND EASTERN NE WHILE A SECONDARY COLD FRONT CURVED
ACROSS THE DAKOTAS. A THIRD AND REAL COLD FRONT WAS ACROSS SOUTH
CENTRAL CANADA... WHICH THE LONG TERM WILL DISCUSS BELOW. UPSTAIRS...
SUBTROPICAL MOISTURE WAS FLOWING NORTHEAST ACROSS THE CWA FROM THE
DESERT SOUTHWEST. A WAVE IN THE SUBTROPICAL FEED WAS NOTED OVER
WESTERN NE. THIS FEATURE IS PROGGED OVER SE MN BY THIS EVENING. A
LITTLE FURTHER NORTHWEST... A TROUGH IN THE POLAR JET WAS NEARING
THE ND/MN BORDER. THE DAY AHEAD WILL FEATURE INCREASING MID LEVEL
FRONTOGENESIS SPREADING NORTHEAST FROM SD/NE... THE INTERACTION
BETWEEN THE TWO WAVES ALOFT. SOME SHOWERS AND ISOLATED
THUNDERSTORMS HAVE ALREADY SPREAD INTO SOUTHWEST AND WEST CENTRAL
MN EARLY THIS MORNING. ALTHOUGH THE ACTIVITY IS MOVING NE A SLIGHT
NORTHWARD DRIFT IS SEEN IN THE OVERALL PATTERN. VARIOUS MODEL
SOLUTIONS SHOW PLENTY OF LAYER RH ALONG WITH THE MID LEVEL
FRONTOGENESIS. HOWEVER...LITTLE TO NO QPF IS PRODUCED WHICH DOES
NOT SEEM RIGHT WHEN LOOKING AT THE ADIABATIC OMEGA AND
SATURATION ON THE 305/310K THETA SURFACES. THE NAM PRODUCES THE
MOST QPF BUT APPEARS TO BE TOO FAR SOUTH INITIALLY. THE PAST FEW
RUNS OF THE HRRR MATCH WELL WITH THE TRENDS AND WOULD SUGGEST THAT
THE SHOWERS AND ISOLATED THUNDERSTORMS OVER WEST CENTRAL MN WILL
MOVE NORTHEAST THIS MORNING WITH A PERIOD OF DRYING IN THEIR WAKE.
THEN...MORE SHOWERS DEVELOP THIS AFTERNOON ACROSS SOUTHERN MN AND
ADJOINING AREAS OF WEST CENTRAL WI AS THE WAVE FROM NE ARRIVES AND
THE MID LEVEL FRONTOGENESIS BEGINS SLIPPING SOUTH. THE SHOWERS
SHOULD THEN END THIS EVENING OVER FAR EASTERN AND SOUTHERN AREAS
FOLLOWED BY DECREASING CLOUDINESS. HIGHS TODAY WILL BE TIED TO THE
CLOUDS AND SHOWERS. THE WARMEST AREAS WILL STRETCH FROM SOUTH
CENTRAL MN THROUGH KEAU WHERE MIDDLE 80S ARE LIKELY. TO THE NORTH
AND WEST... MIDDLE 70S TO LOWER 80S ARE FORECAST. IT WILL STILL BE
MILD TONIGHT WITH LOWS IN THE UPPER 50S TO MIDDLE 60S BUT THAT
WILL CERTAINLY BE CHANGING FOR WEDNESDAY AND THURSDAY MORNINGS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 345 AM CDT TUE SEP 10 2013
MODEL AGREEMENT ON THE EVOLUTION OF THE UPPER AIR PATTERN IS HIGH
THROUGH THE COURSE OF THE WORK WEEK...BUT BEGIN TO DIVERGE
SIGNIFICANTLY OVER THE WEEKEND. DURING THE WEEK...WE WILL SEE A
RE-AMPLIFICATION OF WHAT HAS BECOME THE ALL TOO FAMILIAR H5 PATTERN
SINCE MID JULY OF A WRN NOAM RIDGE AND ERN NOAM THROUGH...WITH NW
FLOW FOR US STUCK IN THE MIDDLE. WITHIN THE RIDGE...A MONSOONAL WAVE
CURRENTLY OVER THE FOUR CORNERS WILL SLOWLY DRIFT NE INTO THE NRN
PLAINS THIS WEEKEND. FROM THERE...TWO DIFFERENT STORIES APPEAR. THE
PROTAGONIST IN BOTH OF THESE STORIES IS A NRN STREAM WAVE THAT WILL
BE WORKING ACROSS THE TOP OF THE RIDGE OVER SRN CANADA THIS WEEKEND.
THE 10.00 ECMWF...10.00 GEM...AND 09.12 GFS DIG THIS NRN WAVE FAR
ENOUGH SOUTH TO PICK UP THE MONSOONAL DISTURBANCE...AND DRIVE A
FAIRLY POTENT POSITIVELY TITLED THROUGH THE GREAT LAKES/UPPER MS
VALLEY SAT NIGHT. THE 10.00 GFS AND 09.12 ECMWF KEEP THIS NRN STREAM
WAVE FAR ENOUGH NORTH THAT THE MONSOONAL WAVE IS LEFT TO WANDER OVER
THE NRN PLAINS WITHIN THE RIDGE FOR THE WEEKEND INTO NEXT WEEK. AS
YOU CAN IMAGINE...WITH THE ECMWF/GFS SWAPPING THEIR POSITIONS
BETWEEN THE 09.12 AND 10.00 RUNS...CONFIDENCE IN THE FORECAST BEGINS
TO DECREASE CONSIDERABLY THIS WEEKEND.
AT THE SFC...WEDNESDAY WILL FEATURE THE PASSAGE OF A SECONDARY COLD
FRONT...THAT WILL GIVE WAY TO COOL/DRY HIGH PRESSURE FOR THU/FRI.
RETURN FLOW SETS UP FOR SATURDAY...WITH RAIN CHANCES RETURNING AS A
RESULT. THE CURRENT RUN OF THE ECMWF /OLD GFS/ DRIVE ANOTHER FRONT
THROUGH SAT NIGHT/SUNDAY...WHILE THE OLD ECMWF /NEW GFS/ KEEP A
MOIST SRLY FETCH GOING THROUGH THE WEEKEND AND INTO NEXT AS THE
MONSOONAL WAVE SITS AND SPINS OVER THE NRN PLAINS.
FOR TEMPERATURES...WEDNESDAY WILL BE THE WARMEST DAY...AS 925-850 MB
TEMPS CONTINUE TO RUN BETWEEN 16C AND 20C. A MAINLY SUNNY DAY IS
EXPECTED IN THE WAKE OF ALL OF TODAY/TONIGHTS WAVINESS...AND MIXING
THESE TEMPS DOWN SUPPORTS HIGHS IN THE LOW/MID 80S. THE SECONDARY
COLD FRONT CLEARING THE AREA WEDNESDAY NIGHT WILL SEND 925-850 MB
TEMPS BACK INTO THE SINGLE DIGITS...WHICH WILL BRING BACK
TEMPERATURES SLIGHTLY BELOW NORMAL TO END THE WEEK. IN ADDITION...
ON FRIDAY MORNING...HIGH PRESSURE WILL BE OVER/AROUND WRN LAKE
SUPERIOR AND THE COMBO OF CLEAR SKIES AND CALM WILL GIVE US OUR
FIRST SHOT AT SEEING SOME FROST /WITH LOWS INTO THE MID 30S/ ACROSS
RUSK/BARRON/DUNN/CHIPPEWA COUNTIES IN WI. BY THE WEEKEND...
TEMPS/THICKNESSES WILL INCREASE...BUT THE RETURN OF CLOUD COVER WILL
HELP HOLD HIGHS BACK AROUND NORMAL...WHICH ARE ALREADY DOWN INTO THE
LOW/MID 70S.
AS FOR PRECIP...MODELS HAVE BEEN TRENDING SLOWER WITH ITS RETURN
OVER THE WEEKEND...SO SLOWED THE EASTWARD ADVANCEMENT OF POPS ACROSS
THE AREA ON SATURDAY AS A RESULT. THE HIGHER POPS IN THE FORECAST
SAT NIGHT INTO SUNDAY WOULD FAVOR THE 10.00 ECMWF SOLUTION...BUT THE
IMPACT OF THE 10.00 GFS /ALONG WITH THE 09.12 ECMWF/ WAS TO HAVE
SLIGHTS CONTINUE INTO MONDAY. DOES NOT LOOK PRECIP AMOUNTS WOULD BE
OVERWHELMING WITH THIS SYSTEM...BUT CONSIDERING MSP HAS ONLY
MEASURED 9 HUNDREDTHS OF AN INCH OF RAIN SINCE 1.33 INCHES FELL ON
AUGUST 6TH...WE WILL TAKE ANYTHING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1110 PM CDT MON SEP 9 2013
LATEST GUIDANCE IS BACKPEDALING AWAY FROM THE IDEA OF FOG...BUT
LOW LEVEL STRATUS WILL BE THE MAIN CONCERN. THE LOWEST CEILINGS
WILL BE FURTHER NORTH...BUT AXN AND STC IN PARTICULAR WILL BE THE
MOST VULNERABLE TO CEILINGS UNDER 2K FT. FOG POTENTIAL MAY BE
LIMITED DUE TO THE DECLINING DEW POINTS AND WESTERLY SURFACE
WINDS. BEYOND THE OVERNIGHT HOURS...VFR CONDITIONS WILL PREVAIL AS
JUST MID AND HIGH CLOUDS WILL BE LEFT OVER. OVERALL...RAISED VSBYS
AND CEILINGS...BUT DUE TO MODEL DISAGREEMENT FROM THE HRRR TO THE
RAP...THIS IS A LOWER CONFIDENCE FORECAST THAT HAS TAKEN THE HRRR
SIDE. IF THE RAP PANS OUT BETTER...WIDESPREAD LOW CEILINGS WILL
AFFECT MSP AND WESTERN WISCONSIN. THERE IS A CHANCE OF SHOWERS
TOMORROW AFTERNOON...BUT DID NOT INTRODUCE AT ANY TAF SITES AT
THIS TIME.
KMSP...CURRENTLY FORECASTING VFR CONDITIONS THROUGH THE TAF
PERIOD...BUT AGAIN THE RAP IS CONCERNING IN THAT IT WANTS TO BRING
IFR CIGS DOWN FROM THE NORTHWEST. CURRENT THINKING IS THAT IT IS
OVER ZEALOUS ON BOUNDARY LAYER MOISTURE SO HAVE TAKEN A MORE
OPTIMISTIC APPROACH. BEYOND MORNING...VFR CONDITIONS WILL PREVAIL.
/OUTLOOK FOR KMSP/
WED...VFR. WINDS NW AT 10KTS
TRU...VFR. WINDS N AT 10KTS.
FRI...VFR. WINDS SE AT 05KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...RAH
LONG TERM...MPG
AVIATION...SPD
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1120 PM CDT MON SEP 9 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 315 PM CDT MON SEP 9 2013
PERHAPS THIS WILL BE THE LAST 90 DEGREE DAY OF THE YEAR FOR THE CWA.
A 24HR LOOP OF WATER VAPOR TOGETHER WITH 500MB HEIGHTS SHOWED THE
UPPER LEVEL RIDGE ACROSS THE SOUTHEASTERN US...WITH A DEAMPLIFYING
SHORTWAVE OVER THE MT/ND BORDER. A SURFACE LOW WAS LOCATED AHEAD OF
THIS SHORTWAVE IN THE EASTERN DAKOTAS...WITH A WELL DEFINED WARM
FRONT EXTENDING EASTWARD THROUGH CENTRAL MN INTO NORTHERN WI. A
TRAILING COLD FRONT EXTENDED SOUTHWEST THROUGH WESTERN NEBRASKA.
THIS SETUP PLACED THE WARM SECTOR DIRECTLY OVER THE CORN BELT
REGION.
DESPITE THE MORNING STRATUS...EARLY AFTERNOON TEMPERATURES
WERE IN THE LOW 90S ACROSS SOUTHERN MN AND WESTERN WI...AS A WARM
NOSE OF H850 TEMPERATURES OF 25C WAS LOCATED OVER SOUTHEASTERN MN.
MECHANICAL MIXING...TOGETHER WITH DIABATIC HEATING SHOULD ALLOW
SURFACE TEMPS TO RAISE A FEW MORE DEGREES YET THIS AFTERNOON. THIS
WILL LEAD TO A CONDITIONALLY UNSTABLE AIRMASS IN THE AFOREMENTIONED
WARM SECTOR. HOWEVER...H700 OF 12-13C SHOULD KEEP THE AIRMASS CAPPED
ACROSS SOUTHERN MN. CLOSER TO THE WARM FRONT INCREASED ISENTROPIC
ASCENT AND UPPER LEVEL FORCING WITH THE APPROACHING 500MB WAVE WILL
SUPPORT THUNDERSTORMS LATER THIS EVENING AND OVERNIGHT. THE 15Z RUN
OF THE HOPWRF DEVELOPS A FEW CONVECTIVE CELLS NORTH OF THE METRO
INTO WESTERN WI. DEEP LAYER SHEAR OF AROUND 40KTS...TOGETHER WITH
VEERING WINDS IN THE LOWER LEVELS ALONG THE WARM FRONT WILL SUPPORT
SUPERCELLS ALONG WITH THE THREAT OF A TORNADO EARLY ON WHERE THE
LOWER LCLS AND HIGH HELICITY VALUES OF THE WARM FRONT MEET THE
EAST/WEST CAPE GRADIENT. MOST OF THE HIRES MODELS...SUCH AS THE SPC
WRFNMM AND HRRR...ALSO WANT TO DEVELOP THUNDERSTORMS ALONG THE COLD
FRONT. THERE IS NOT MUCH LOW LEVEL CONVERGENCE ALONG THE COLD
FRONT...ESPECIALLY CONSIDERING THE STRONG CAP IN PLACE...SO
THEREFORE THINK THE WARM FRONT HAS THE HIGHEST POTENTIAL FOR SEVERE
WEATHER.
LATER TONIGHT THE LOW LEVEL MOISTURE WILL SUPPORT LOW STRATUS AND
PATCHY FOG...ESPECIALLY ACROSS THE NORTHERN PORTION OF THE CWA.
THEREFORE ADDED PATCH FOG TO THE GRIDS. ON TUESDAY THE SURFACE
BOUNDARY WILL BE ACROSS THE FAR EASTER PART OF THE CWA...AND THIS
WILL ONCE AGAIN BE THE FOCUS FOR A FEW AFTERNOON SHOWERS AND
THUNDERSTORMS. THEREFORE HAVE THE PRECIP CHANCES TAPERING OFF BY
EARLY TUESDAY MORNING...AND RETURNING LATE TUESDAY AFTERNOON.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 315 PM CDT MON SEP 9 2013
COOLER /BUT NOT COOL/ TEMPERATURES WILL ARRIVE IN THE WAKE OF THE
COLD FRONT FOR TUESDAY AND WEDNESDAY...ALTHOUGH THE NOTABLY COOLER
AIR WILL NOT BE FELT UNTIL THURSDAY AS BROAD SURFACE HIGH PRESSURE
SETTLES IN BEHIND A SECONDARY COLD FRONT. HIGHS GENERALLY FROM 78
TO 85 WILL PREVAIL FOR TUESDAY AND WEDNESDAY...WITH HIGHS FROM 65
TO 75 ON THURSDAY AND FRIDAY. AS FAR AS PRECIPITATION GOES FOR THE
REMAINDER OF THE WORK WEEK...COULD SEE A FEW SHOWERS IN
THE FAR SOUTHEAST ON TUESDAY EVENING /MAINLY INTERSTATE 90
CORRIDOR/ AS WEAK MID LEVEL SHORTWAVE ENERGY PASSES OVER WITH THE
DEPARTING FRONT NEARBY. OTHERWISE...DRY CONDITIONS ARE EXPECTED
THROUGH FRIDAY.
MODELS ARE STILL FORECASTING A TRANSITION TO RETURN FLOW ON FRIDAY
NIGHT...WITH A NOTABLE LOW LEVEL JET PROGGED TO INSTIGATE THE
DEVELOPMENT SHOWERS AND THUNDERSTORMS ON SATURDAY AND SUNDAY.
UNFORTUNATELY...THERE ARE STILL A FAIR AMOUNT OF DIFFERENCES
BETWEEN THE ECMWF AND GFS REGARDING TIMING. HAVE RETAINED HIGH
CHANCE POPS AT THIS POINT. BY NEXT MONDAY...WIDESPREAD HIGHS IN
THE 60S APPEAR REASONABLE...WITH LOWS IN THE 40S /POSSIBLY EVEN
UPPER 30S OVER WEST CENTRAL WI/.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1110 PM CDT MON SEP 9 2013
LATEST GUIDANCE IS BACKPEDALING AWAY FROM THE IDEA OF FOG...BUT
LOW LEVEL STRATUS WILL BE THE MAIN CONCERN. THE LOWEST CEILINGS
WILL BE FURTHER NORTH...BUT AXN AND STC IN PARTICULAR WILL BE THE
MOST VULNERABLE TO CEILINGS UNDER 2K FT. FOG POTENTIAL MAY BE
LIMITED DUE TO THE DECLINING DEW POINTS AND WESTERLY SURFACE
WINDS. BEYOND THE OVERNIGHT HOURS...VFR CONDITIONS WILL PREVAIL AS
JUST MID AND HIGH CLOUDS WILL BE LEFT OVER. OVERALL...RAISED VSBYS
AND CEILINGS...BUT DUE TO MODEL DISAGREEMENT FROM THE HRRR TO THE
RAP...THIS IS A LOWER CONFIDENCE FORECAST THAT HAS TAKEN THE HRRR
SIDE. IF THE RAP PANS OUT BETTER...WIDESPREAD LOW CEILINGS WILL
AFFECT MSP AND WESTERN WISCONSIN. THERE IS A CHANCE OF SHOWERS
TOMORROW AFTERNOON...BUT DID NOT INTRODUCE AT ANY TAF SITES AT
THIS TIME.
KMSP...CURRENTLY FORECASTING VFR CONDITIONS THROUGH THE TAF
PERIOD...BUT AGAIN THE RAP IS CONCERNING IN THAT IT WANTS TO BRING
IFR CIGS DOWN FROM THE NORTHWEST. CURRENT THINKING IS THAT IT IS
OVER ZEALOUS ON BOUNDARY LAYER MOISTURE SO HAVE TAKEN A MORE
OPTIMISTIC APPROACH. BEYOND MORNING...VFR CONDITIONS WILL PREVAIL.
/OUTLOOK FOR KMSP/
WED...VFR. WINDS NW AT 10KTS
TRU...VFR. WINDS N AT 10KTS.
FRI...VFR. WINDS SE AT 05KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...LS
AVIATION...SPD
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
356 AM CDT TUE SEP 10 2013
.DISCUSSION...
FORECAST CONCERNS THROUGH WEDNESDAY EVENING WILL BE PRECIPITATION
COVERAGE ALONG AND BEHIND THE COLD FRONT...THEN COOLER AND DRIER
WEATHER THURSDAY AND FRIDAY.
LINCOLN TIED THEIR RECORD OF 100 DEGREES MONDAY SET BACK IN 1931.
OMAHA EPPLEY JUST MISSED THE RECORD WITH A HIGH OF 99 AND NORFOLK
TOPPED OUT AT 97. OMAHA DID TIE A RECORD WARM MINIMUM FOR MONDAY
WITH 75 DEGREES (TIED WITH 1983/1931 AND 1927).
THE 00Z UPPER AIR MAPS HAD A 90KT H3 JET OVER NORTH DAKOTA WITH THE
H5 TROF SIMILARLY OVER NORTH DAKOTA...EXTENDING SOUTHWEST TOWARD
ARIZONA AND SOUTHERN CALIFORNIA. WARM H7 TEMPERATURES OF +10 TO +13C
EXTENDED ACROSS MUCH OF THE CENTRAL PLAINS...WITH THE THERMAL
GRADIENT FROM NORTHWEST NEBRASKA NORTHWARD ACROSS THE NORTHERN
PLAINS. H7 MOISTURE WAS NOTED ON THE WATER VAPOR IMAGERY AND UA
CHARTS FROM THE SOUTHWEST U.S. INTO THE UPPER MIDWEST. AT H85 THE
THERMAL RIDGE EXTENDED FROM SOUTHWEST NEBRASKA AND NORTHWEST KANSAS
NORTHEAST ACROSS THE FORECAST AREA WITH THE GRADIENT COMPARABLE TO
THE H7 PATTERN ACROSS THE DAKOTAS. ALTHOUGH THE SURFACE FRONT HAS
PUSHED INTO THE CWA AND THE OAX RADAR SHOWED A BOUNDARY
APPROACHING VALLEY WITH A WIND SHIFT AT KFET. THE SURFACE WINDS
WERE LIGHT FROM THE SOUTH AT KOFK AGAIN. THE WSR-88D MOSAIC HAD
THE LEADING EDGE OF THE PRECIPITATION FROM BROKEN BOW TO MITCHELL
SOUTH DAKOTA INTO SOUTHWEST MINNESOTA AT 06Z AND BY 0830Z THERE
WERE A FEW ECHOES IN BOYD AND KNOX COUNTIES...BUT NOT MUCH
REACHING THE GROUND. THE TREND ON THE IR SATELLITE LOOP SHOWED
EXPANDING/COOLING TOPS WITH THE PRECIPITATION. WPC HAD THE
EXCESSIVE DAY 1 RAINFALL OVER THE SOUTHWEST U.S. INTO WESTERN
COLORADO.
TODAY...THE NORTHERN PLAINS SHORT WAVE TROF WILL CONTINUE TO SHIFT
EAST ACROSS MINNESOTA INTO WISCONSIN...WHILE THE H5 LOW OVER THE
SOUTHWEST U.S. CUTS OFF. THIS WILL SLOW THE PUSH OF THE FRONT TO
SOMEWHERE ALONG I80 THROUGH 00Z. THE LOW LEVEL JET WILL STRENGTHEN
THIS ACROSS NORTH CENTRAL KANSAS INTO CENTRAL NEBRASKA AND THE
OAX FORECAST AREA...WITH ISENTROPIC LIFT AND SATURATION NORTH OF
THE FRONT IN PARTS OF NORTHEAST NEBRASKA. THE FORCING THIS
MORNING WILL MAINLY BE NORTHWEST OF THE FORECAST AREA BUT COULD
CLIP THE COUNTIES NEAR THE SD BORDER. FARTHER SOUTH THE FORCING
IS MORE NEGLIGIBLE. THE MODELS ARE HINTING AT A SECOND AREA OF
SATURATION FARTHER SOUTH CLOSER TO I80...BUT FOR NOW WILL INCREASE
CLOUDS AND MAY INCLUDE SPRINKLES MENTION. THIS AFTERNOON...THERE
IS WEAK CONVERGENCE ALONG THE FRONT AND A DECENT THERMAL BOUNDARY
IS EXPECTED. MODELS KEEP IS MAINLY DRY...HOWEVER HRRR DOES
GENERATE PRECIP ALONG THE FRONT. WILL MAINTAIN ISOLATED POPS ALONG
AND BEHIND THE FRONT WHERE DEEPER MOISTURE IS PRESENT WITH COOLING
ALOFT. TEMPERATURES TODAY SHOULD BE HOT AHEAD OF THE FRONT AND
WHERE THERE IS SUNSHINE. CLOUDS WILL IMPACT HIGHS...BUT GENERALLY
HAVE READINGS AROUND 80 NORTH NEAR THE SD BORDER TO THE UPPER 90S
NEAR THE MISSOURI AND KANSAS BORDERS.
TONIGHT THROUGH WEDNESDAY NIGHT THE MID TROPOSPHERIC TROF
DEEPENS OVER THE GREAT LAKES AND THE SURFACE FRONT IS PUSHED
FARTHER SOUTH. MONSOONAL MOISTURE STREAMING INTO THE ROCKIES AND
MAKING IT INTO THE PLAINS...POOLING AHEAD OF THE TROF COMBINE WITH
THE LOW...MID AND UPPER LEVEL SUPPORT WILL PROVIDE AT LEAST SOME
CHANCES FOR PRECIPITATION DURING THE PERIOD...ALTHOUGH COVERAGE
STILL LOOKS SCATTERED TO ISOLATED FOR THE COUNTY WARNING AREA.
HIGHS WEDNESDAY SHOULD RANGE FROM THE LOWER 80S NORTH TO THE LOWER
90S SOUTH.
COOL HIGH PRESSURE BUILDS IN FOR THURSDAY AND FRIDAY WITH MAINLY
DRY CONDITIONS. NEAR NORMAL HIGHS AROUND 80S THURSDAY WITH BELOW
NORMAL HIGHS IN THE 70S FRIDAY.
SATURDAY THROUGH TUESDAY...AS THE SURFACE HIGH
RETREATS...SOUTHWEST FLOW WILL RETURN DEEPER MOISTURE TO THE AREA
AND SHOWERS WILL TRY TO RETURN TO THE WESTERN CWA FRIDAY NIGHT.
SHORTWAVE TROF ENERGY ADVANCES INTO THE PLAINS SATURDAY THROUGH
SUNDAY...SO THERE APPEARS TO BE A GOOD SHOT AT PRECIPITATION
DURING THIS PERIOD. BEYOND THIS PERIOD...THERE IS NOT GOOD MODEL
CONSENSUS...BUT PRECIP CHANCES COULD LINGER INTO MONDAY. HIGHS
STILL BELOW NORMAL FOR MUCH OF THE EXTENDED.
&&
.AVIATION...
06Z TAFS FOR KOMA...KLNK...AND KOFK.
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF CYCLE. WINDS HAVE
GONE LIGHT/VARIABLE AT KOFK...AND WILL INCREASE OUT OF THE
NORTHEAST BY MID-MORNING. KEPT SHRA/TSRA MENTION OUT OF THE TAF
FOR NOW WITH UNCERTAINTY ON IF/WHEN SHRA WILL MOVE INTO NORTHEAST
NEB...AND COVERAGE OF ANY SHRA THAT DOES MOVE IN. FRONT SHOULD
REMAIN NORTH OF KOMA/KLNK UNTIL EVENING...WITH WINDS BECOMING
LIGHT/VARIABLE AFTER 02Z KOMA/CLOSER TO MIDNIGHT KLNK AS FRONT
APPROACHES. INCLUDED MID-LEVEL CEILINGS...BUT AGAIN...NO SHRA
MENTION AT THIS POINT UNTIL CONFIDENCE ON COVERAGE IMPROVES.
MAYES
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS BUFFALO NY
417 AM EDT TUE SEP 10 2013
.SYNOPSIS...
A WARM FRONT WILL CONTINUE TO LIFT NORTHEASTWARD ACROSS THE EASTERN
GREAT LAKES REGION THIS MORNING...ACCOMPANIED WITH SHOWERS AND
THUNDERSTORMS. BEHIND THIS WARM FRONT CLOUDS WILL BREAK FOR SOME
SUNSHINE LATER TODAY WHICH WILL AID IN AN UNSEASONABLY HOT AND
MUGGY AFTERNOON. THESE VERY WARM AND HUMID CONDITIONS WILL PERSIST
THROUGH WEDNESDAY NIGHT. EXPECT SHOWERS AND THUNDERSTORMS TO BREAK
OUT WEDNESDAY NIGHT AND THURSDAY AHEAD OF A COLD FRONT THAT WILL
BRING A RETURN TO MUCH COOLER WEATHER BY THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
REGIONAL RADARS AND SATELLITE IMAGERY THIS MORNING DISPLAY A LARGE
MCS NEAR GEORGIAN BAY AND ADVANCING SOUTH AND EASTWARD ACROSS
SOUTHERN CANADA AND JUST NORTH OF LAKE ONTARIO. SOUTH OF THIS
FEATURE A FEW SHOWERS ARE BLOSSOMING ACROSS THE SOUTHERN PENINSULA
OF ONTARIO AND DRIFTING ACROSS LAKE ERIE. AT THE SURFACE A WARM FRONT IS
PUSHING NORTHWARD FROM THE OHIO VALLEY AND INTO WESTERN NEW YORK
THIS MORNING. TODAY WILL BE AN ACTIVE DAY WITH SHOWERS AND
THUNDERSTORMS PRIMARILY THROUGH THE MORNING HOURS FOR THE CWA...WITH
ATTENTION THEN TURNING TO THE GUSTY WINDS AND AFTERNOON HEAT.
THUNDERSTORMS...
MOISTURE ADVECTION BEHIND THE LIFTING WARM FRONT...ALONG WITH
ISENTROPIC UPGLIDE ALONG A 35 TO 40 KNOT LOW LEVEL JET WILL CONTINUE
TO FUEL THE POTENTIAL FOR SOME SHOWERS AND A FEW THUNDERSTORMS
ACROSS WNY THIS EARLY MORNING. WITH THE LATEST RADAR IMAGES
DISPLAYING A FEW CONVECTIVE SHOWERS ACROSS CANADA...AND WITH SUPPORT
FROM THE MESO SCALE MODELS OF THE HRRR AND YESTERDAYS SSEO...EXPECT
THIS ACTIVITY TO INCREASE IN COVERAGE AREA SOME THIS MORNING AS IT
DRIFTS EAST-SOUTHEASTWARD ACROSS WNY. AFTER SUNRISE WITH DAYTIME
MIXING...AND LOWERING DEW POINTS TO THE EAST EXPECT THIS SCATTERED
ACTIVITY TO QUICKLY DIMINISH IN COVERAGE AREA AS IT SHIFTS DEEPER
INTO WESTERN NEW YORK.
ALSO THIS MORNING EXPECT THE LARGE MCS OVER SOUTHERN CANADA TO DROP
SOUTHEASTWARD...FOLLOWING A STREAM OF HIGHER THETA-E AIR AND ALONG
THE 1000-500 THICKNESS LINES. THIS TRACK WILL BRING A CLUSTER OF
SHOWERS AND THUNDERSTORMS TO LAKE ONTARIO...AND THEN THROUGH THE
EASTERN LAKE ONTARIO REGION. ON THE SOUTHERN PERIPHERY SOME ACTIVITY
MAY BRUSH BY THE LINE OF COUNTIES JUST SOUTH OF LAKE
ONTARIO...ESPECIALLY THE WAYNE-CAYUGA CORRIDOR. THE CONVECTIVE
ACTIVITY WILL ENTER THE CWA BEFORE DAWN AND CLEAR THROUGH THE CWA
WITHIN A FEW HOURS AFTER DAWN.
LATER IN THE DAY...AND BEHIND THE MCS...THERE WILL ALSO BE A CHANCE
FOR A FEW THUNDERSTORMS ALONG THE WARM FRONTAL BOUNDARY THAT WILL
STALL NEAR THE U.S. AND CANADIAN BORDER. AREAS POSSIBLE FOR STORMS
WILL LARGELY BE CONFINED TO THE EASTERN LAKE ONTARIO REGION. IN
ADDITION TO THE SBCAPES OF 1000 TO 1500 J/KG THROUGH THIS
REGION...THERE WILL BE A SLIGHTLY STRONGER LLJ IN ADDITION TO THE
WARM FRONTAL BOUNDARY THAT COULD CONTINUE TO INITIATE CONVECTION.
WITH THE PASSAGE OF THE LARGE MCS FEEL THAT SHOWER AND THUNDERSTORM
ACTIVITY BEHIND THIS FEATURE WILL JUST BE SCATTERED IN NATURE AND
FOCUS MORE UPON THE INLAND HILLS AND WILL QUICKLY DROP POPS DOWN TO
THE CHANCE RANGE FROM MID MORNING ONWARD. WITH DECENT HELICITY OF
200 T0 400 M2/S2...DECENT DIRECTIONAL SHEER AND CONTINUED 35 TO 40
KNOT LLJ AROUND 925 HPA THERE WILL BE THE CONTINUED THREAT THAT ANY
THUNDERSTORM COULD BECOME STRONG WITH GUSTY WINDS AND HAIL THROUGH
THE AFTERNOON AND EARLY EVENING HOURS.
HEAT...
BEHIND THIS WARM FRONT UNSEASONABLY WARM TEMPERATURES WILL BE
FOUND AS THE RECENT HEAT ACROSS THE PLAINS SLIDES NORTHEASTWARD. THE
CENTER OF A 592 DM 500 HPA RIDGE WILL REMAIN WELL TO OUR SOUTH OVER
THE SOUTHEASTERN STATES...BUT ITS AXIS WILL CROSS THE EASTERN GREAT
LAKES REGION TODAY. AT 850 HPA TEMPERATURES WILL RISE TO 20 TO AS
MUCH AS 22C WHICH WOULD FACTOR AT 2 SD ABOVE NORMAL. THESE
TEMPERATURES ALOFT WILL TRANSLATE TO AFTERNOON HIGHS WELL IN TO THE
80S...WITH THE VALLEYS WARMER INCLUDING THE GENESEE VALLEY WHERE LOW
90S ARE LIKELY. A SOUTHWEST WIND OFF A LOW 70S LAKE WILL KEEP AREAS
AROUND BUFFALO AND JUST NORTH OF WATERTOWN A FEW DEGREES COOLER. FOR
MORE DETAILS ON RECORD TEMPERATURES TODAY AND WEDNESDAY PLEASE
REFERENCE THE CLIMATE SECTION BELOW. WITH THE WARMEST DAYS THIS YEAR
IN THE LOW TO MID 90S ACROSS THE REGION...TODAY WILL BE ONE OF THE
WARMEST DAYS THIS YEAR...AND POSSIBLY A FEW LOCATIONS IN THE GENESEE
VALLEY COULD HAVE A SHOT OF TUESDAY BEING THE WARMEST DAY OF THE
YEAR. WHEN FACTORING IN THE HUMIDITY THIS AFTERNOON`S APPARENT
TEMPERATURES WILL SOAR WELL INTO THE 90S ACROSS THE LOWER ELEVATIONS
OF WESTERN NEW YORK...AND POSSIBLY UPPER 90S WITHIN THE GENESEE
VALLEY AND NORTHERN FINGER LAKES REGION.
WINDS...
TODAY WILL ALSO BE QUITE BREEZY AS THE PRESSURE GRADIENT
INCREASES BETWEEN HIGH PRESSURE ARCHED ALONG THE EAST COAST AND THE
LOW PRESSURE/COLD FRONT WHICH WILL BE ADVANCING INTO THE SOUTHERN
ONTARIO PENINSULA TODAY. ALSO AIDING IN THE STRONGER WINDS TODAY
WILL BE DAYTIME MIXING. THOUGH RECENT RUNS OF THE 00Z NAM AND GFS
SUGGEST SLIGHTLY LESS OF A LLJ THAN PRIOR RUNS TODAY SHOULD STILL BE
ON THE WINDY SIDE ESPECIALLY DOWNWIND OF THE LAKES. SOUTHWEST WINDS
WILL AID IN WARMING THE VALLEYS OF THE CWA...WHILE ALSO GUSTING
DOWNWIND OF LAKE ERIE INTO THE 35 TO 40 MPH RANGE.
THESE SOUTHWEST WINDS BEHIND A WARM FRONT THAT WILL STALL NEAR THE
U.S. AND CANADIAN BORDER WILL ALSO BRING INCREASING MOISTURE AND
HUMIDITY INTO THE REGION. DEWPOINTS WILL RISE INTO THE MID AND UPPER
60S...WHICH COMBINED WITH THE VERY WARM TEMPERATURES WILL BRING
IMPRESSIVE SBCAPE VALUES TO OUR REGION. SBCAPES RANGING FROM 2000 TO
JUST OVER 2500 J/KG ARE POSSIBLE BEHIND THIS WARM FRONT...HOWEVER
WITH NO TRIGGER TO INITIATE CONVECTION (UPPER LEVEL SHORTWAVE RIDING
TO OUR NORTH ALONG THE CANADIAN BORDER) AS WELL AS WARMING IN THE
MID LEVELS...WILL LEAVE AREAS SOUTH OF THE WARM FRONT DRY AFTER THE
SCATTERED EARLY MORNING ACTIVITY. EXPECT CLOUDS TO DIMINISH THROUGH
THE DAY TIME SOUTH OF LAKE ONTARIO.
TUESDAY NIGHT WILL CONTINUE TO BE MUGGY AND LARGELY BE QUIET SOUTH
OF LAKE ONTARIO...WHILE THE STALLING WARM FRONT WILL CONTINUE THE
POTENTIAL FOR A FEW SHOWERS AND THUNDERSTORMS OVERNIGHT ACROSS THE
NORTH COUNTRY. CENTERED WITHIN THE WARM SECTOR OF THIS STORM SYSTEM
THIS NIGHT WILL BE UNSEASONABLY WARM WITH TEMPERATURES LIKELY TO NOT
DROP OUT OF THE LOW 70S ACROSS MUCH OF THE CWA. INLAND AND ACROSS
THE HILL TOPS WILL BE SLIGHTLY COOLER AND THESE AREAS WILL BE THE
LOCATIONS THAT WILL DROP INTO THE UPPER 60S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ANOTHER UNSEASONABLY HOT AND HUMID DAY IN STORE FOR WESTERN AND
NORTH CENTRAL NEW YORK WEDNESDAY...AS THERMAL BUBBLE REMAINS ACROSS
THE REGION AHEAD OF SLOW MOVING COLD FRONT. RIBBON OF 850 MB
TEMPERATURES AROUND 20C SHOULD ONCE AGAIN SUPPORT AFTERNOON
TEMPERATURES WELL INTO THE 80S TO PERHAPS THE LOWER 90S IN THE
VALLEYS AND ALONG THE LAKE PLAINS. SURFACE DEWPOINTS IN THE MID 60S
WILL SEND APPARENT TEMPERATURES INTO THE MID 90S. CONVECTIVE CHANCES
WEDNESDAY LOOK PROBLEMATIC WITH LITTLE FORCING FORECAST ACROSS THE
REGION WITH THE COLD FRONT STILL OFF TO OUR NORTHWEST. ALTHOUGH THE
PRE-FRONTAL ENVIRONMENT WILL BECOME INCREASINGLY UNSTABLE...IT LOOKS
TO BE LARGELY CAPPED WITH A WARM NOSE AROUND 800 MB STILL NOTED ON
MODEL SOUNDINGS. PRIMARY THREAT FOR CONVECTION WILL BE ALONG
LOCALIZED LAKE BREEZE BOUNDARIES INLAND FROM THE LAKES. IF
THUNDERSTORMS CAN DEVELOP...ISOLATED SEVERE STORMS ARE POSSIBLE WITH
DECENT SURFACE BASED CAPE PROFILES AND MAINTENANCE OF STRONG
KINEMATICS.
MORE INTERESTING SET UP DEVELOPING WEDNESDAY NIGHT AND THURSDAY AS
NEXT WAVE AND SHARPER TROUGHING ARRIVES...REINVIGORATING THE
APPROACHING COLD FRONT. THE RESULTING ENHANCEMENT OF MID AND
UPPER-LEVEL ASCENT FIELDS WILL MAKE THE LATE WEDNESDAY NIGHT AND
EARLY THURSDAY TIME FRAME THE PRIME PERIOD FOR SHOWER AND
THUNDERSTORM DEVELOPMENT WITHIN THE NARROW MID-LEVEL THETA-E RIBBON
ALONG THE FRONT. SHEAR PROFILES SUGGEST SOME POTENTIAL FOR DAMAGING
WIND GUSTS IF MORE ORGANIZED CONVECTION CAN DEVELOP.
THE FRONT IS EXPECTED TO BE THROUGH OUR AREA BY EARLY THURSDAY
AFTERNOON WITH NOTABLY DRIER AND COOLER CANADIAN AIR CLEARING OUT
OUR SKIES FROM THE NORTHWEST. WILL TAPER OFF THE POPS ACCORDINGLY
WITH ONLY SLGT CHC POPS REMAINING EAST OF ROCHESTER BY EVENING. IN
TERMS OF TEMPERATURES...WE SHOULD MAX OUT IN THE MID 70S EARLY IN
THE DAY WITH STEADY OR SLOWLY FALLING MERCURY READINGS ANTICIPATED
FOR THE AFTERNOON WHEN DEW POINTS WILL DROP OFF THROUGH THE 50S.
OUR ATTENTION WILL TURN FROM SYNOPTIC TO MESOSCALE THURSDAY NIGHT AS
SEASONABLY CHILLY AIR WILL POUR ACROSS THE LOWER LAKES IN ADVANCE OF
AN EXPANSIVE AREA OF HIGH PRESSURE OVER WESTERN ONTARIO. H85 TEMPS
ARE PROJECTED TO DROP TO ARND 4C BY DAYBREAK FRIDAY...AND WITH A
DEEP CYCLONIC NORTHWEST FLOW IN PLACE...THERE WILL CERTAINLY BE
ENOUGH LAKE INSTABILITY TO SUPPORT SOME LAKE CLOUDINESS...AND
POSSIBLY NUISANCE SHOWERS EAST/SOUTHEAST OF LK ONTARIO. LOW
TEMPERATURES WILL RANGE FROM THE LOWER 50S ACROSS THE LAKE PLAINS TO
THE MID 40S IN THE SRN TIER VALLEYS/EAST OF THE BLACK RIVER VALLEY.
THESE READINGS WILL BE AT LEAST 15 DEG F LOWER THEN PREVIOUS NIGHTS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
TEMPERATURES WILL AVERAGE NEAR TO BELOW NORMAL DURING THIS PERIOD AS
AN AMPLIFIED LONGWAVE PATTERN OVER THE LOWER 48 WILL BREAK DOWN...
LEAVING MORE OF A ZONAL FLOW ACROSS OUR REGION.
A VIGOROUS SHORTWAVE WILL DROP INTO THE BASE OF A LONGWAVE TROUGH
CENTERED OVER THE LOWER GREAT LAKES ON FRIDAY. THIS FEATURE WILL
COUPLE WITH STRONG COLD ADVECTION TO PRODUCE SOME SHOWERS SOUTH OF
LAKE ONTARIO DURING THE MIDDAY AND AFTERNOON...WHILE TEMPERATURES
WILL STRUGGLE TO REACH 60. THE STRONG MID LEVEL FEATURE WILL SWING
OFF ACROSS NEW ENGLAND FRIDAY NIGHT...WHILE STRONG RIDGING WILL
BUILD IN FROM THE UPPER GREAT LAKES. THIS WILL QUICKLY CLEAR OUT ANY
LEFTOVER SHOWER ACTIVITY...ALTHOUGH SOME NUISANCE LAKE DRIVEN
SHOWERS CANNOT BE RULED OUT WITHIN WEAK CYCLONIC FLOW BETWEEN ROC
AND SYR.
BOTH DAYS OF THE WEEKEND WILL THEN BE DOMINATED BY AN EXPANSIVE AREA
OF HIGH PRESSURE THAT WILL BE PARKED OVER THE GREAT LAKES REGION.
WHILE IT WILL BE SEASONABLY COOL ON SATURDAY WITH HIGHS CLOSE TO
60...WEAK WARM ADVECTION DURING THE SECOND HALF OF THE WEEKEND WILL
BOOST DAYTIME TEMPS BY SOME 10 DEGREES FOR SUNDAY. THIS WILL
TRANSLATE INTO READINGS THAT WILL BE RIGHT ON TARGET FOR NORMALS IN
MID SEPTEMBER...WHICH ARE WITHIN A FEW DEGREES OF 70.
CONFIDENCE IN THE FORECAST WILL DROP OFF SIGNIFICANTLY ON MONDAY...
AS THE DETERMINISTIC PACKAGES ARE AT ODDS OVER THE PASSAGE OF THE
NEXT FRONTAL SYSTEM. WILL CARRY SLGT CHC POPS FOR NOW WHILE LEAVING
TEMPS CLOSE TO THOSE FROM SUNDAY.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
AT 06Z VFR FLIGHT CONDITIONS WERE COMMON ACROSS THE REGION...WITH
MID LEVEL CLOUDS DIVING SOUTHEASTWARD. EXPECT SOME LOWERING TO MVFR
AND LOWER AS MOISTURE BUILDS AND SHOWERS AND THUNDERSTORMS INCREASE
IN COVERAGE AREA AND CROSS THE REGION.
THROUGH THE EARLY MORNING HOURS A STRONG WARM FRONT WILL CROSS THE
REGION WITH INCREASING COVERAGE OF SHOWERS ACROSS MUCH OF THE
AREA...ALONG WITH A FEW EMBEDDED THUNDERSTORMS. THUNDERSTORMS THIS
MORNING WILL BE MOST LIKELY ACROSS LAKE ONTARIO AND THE EASTERN LAKE
ONTARIO REGION AS AN UPSTREAM MCS CONTINUES TO NEAR THE REGION THIS
MORNING. THIS ACTIVITY WILL BRING BRIEF PERIODS OF MVFR/IFR
CONDITIONS IN ANY OF THE HEAVIER SHOWERS. THE SHOWERS AND ANY
THUNDER WILL END FROM SOUTHWEST TO NORTHEAST TUESDAY MORNING AS THE
WARM FRONT LIFTS NORTHEAST ACROSS THE AREA. ANY LINGERING MVFR/IFR
CONDITIONS ASSOCIATED WITH THE SHOWERS WILL ALSO END.
FOLLOWING THE WARM FRONT...SKIES WILL CLEAR AND WINDS WILL BECOME
RATHER STRONG WITH GUSTS OF AROUND 30 KNOTS LIKELY ACROSS WESTERN NY
FROM KBUF-KIAG-KROC...WITH 20-25 KNOTS ELSEWHERE.
SOME LOW LEVEL WIND SHEAR IS LIKELY TONIGHT AS THE WARM FRONT LIFTS
NORTHEASTWARD AND A 35-40 KNOT LOW LEVEL JET CROSSES THE AREA. WINDS
WILL STILL BE STRONG JUST OFF THE DECK ON TUESDAY...BUT AS SURFACE
WINDS INCREASE THIS WILL ALLEVIATE ANY SHEAR.
WINDS WILL DIMINISH SOME THIS EVENING AS THE LOW PRESSURE WEAKENS
SOME...AND THE PRESSURE GRADIENT RELAXES. THOUGH WE WILL LOSE THE
STRONG GUSTS AND STILL SOUTHWEST WIND AROUND 10 KNOTS AND OCCASIONAL
LIGHT GUSTS WILL BE COMMON.
OUTLOOK...
WEDNESDAY...VFR.
WEDNESDAY NIGHT AND THURSDAY...MAINLY VFR WITH SHOWERS LIKELY AND
A CHANCE OF THUNDERSTORMS ALONG WITH ASSOCIATED BRIEF MVFR/IFR.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
SATURDAY...VFR.
&&
.MARINE...
SOUTHWEST WINDS WILL CONTINUE TO STRENGTHEN TODAY WITH SUSTAINED
WINDS AROUND 20 KNOTS ON LAKE ERIE...ACROSS THE NIAGARA RIVER AND
ACROSS THE WESTERN HALF OF LAKE ONTARIO. WILL CONTINUE THE SCA FOR
THESE AREAS TODAY...AS WELL AS THE EASTERN END OF LAKE ONTARIO
WHERE WINDS WILL AVERAGE 15 TO 20 KNOTS...AND WAVES NEAR 4 FOOT IN
THE NORTHEAST CORNER OF THE LAKE.
THESE WINDS SHOULD RELAX TUESDAY NIGHT AS THE LOW PRESSURE WEAKENS.
SHOWERS AND THUNDERSTORMS WILL BE A THREAT ONCE AGAIN WEDNESDAY
NIGHT INTO THURSDAY AHEAD OF A COLD FRONT THAT IS EXPECTED TO CROSS
THE LAKES LATER ON THURSDAY...BRINGING ANOTHER CHANCE OF SMALL CRAFT
ADVISORY LEVEL NORTHWESTERLY WINDS THURSDAY NIGHT AND FRIDAY.
&&
.CLIMATE...
TUESDAY AND WEDNESDAY A LATE SUMMER AIRMASS WILL SETTLE ACROSS
THE REGION WITH MANY AREAS WELL INTO THE 80S. BELOW ARE THE RECORD
HIGHS...AND RECORD WARM LOWS FOR OUR THREE CLIMATE SITES:
BUFFALO..
TUESDAY HIGH: 90 (1955) LOW: 75 (1983)
WEDNESDAY HIGH: 87 (1952) LOW: 72 (1931)
ROCHESTER..
TUESDAY HIGH: 94 (1897) LOW: 73 (1925)
WEDNESDAY HIGH: 94 (1931) LOW: 71 (1931)
WATERTOWN..
TUESDAY HIGH: 90 (1959) LOW: 70 (1962)
WEDNESDAY HIGH: 89 (1961) LOW: 70 (1961)
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 6 PM EDT THIS
EVENING FOR LEZ020-040-041.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 6 PM
EDT THIS EVENING FOR LOZ030.
SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 8 PM EDT
THIS EVENING FOR LOZ042-043.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
LOZ045.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...THOMAS
SHORT TERM...RSH/TMA
LONG TERM...RSH
AVIATION...THOMAS
MARINE...THOMAS
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
403 AM EDT TUE SEP 10 2013
.SYNOPSIS...
THE NEXT COUPLE OF DAYS WILL FEATURE A BRIEF RETURN TO SUMMER
WEATHER BEFORE TEMPERATURES COOL BACK OFF TO MORE FALL-LIKE
LEVELS BY THE END OF THE WEEK AND INTO THE WEEKEND. THERE WILL
ALSO BE SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS FROM LATE
TONIGHT THROUGH THURSDAY...SOME POTENTIALLY STRONG TO
SEVERE...ESPECIALLY LATE WEDNESDAY.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
AS OF 1258 AM EDT TUESDAY...ONLY MINOR ADJUSTMENTS MADE TO HOURLY
PARAMETERS FOR NEXT SEVERAL HOURS BASED ON LATEST OBSERVATIONAL
DATA AND NEAR TERM GUIDANCE. SHOWERS APPROACHING ST LWR VLY...AND
WILL CONTINUE TO MONITOR MCS OVER NORTHERN GRTLKS AS IT MOVES
SEWRD OVRNGHT.
PREVIOUS DISCUSSION...
MOSTLY MINOR TWEAKS MADE TO TEMPERATURES AND DEWPOINTS TO ACCOUNT
FOR LATEST SFC OBSERVATIONS. HOWEVER...AN ELEVATED MCS THAT IS NOW
EXITING LAKE SUPERIOR HAS RESULTED IN SOME MORE SIGNIFICANT
CHANGES TO POPS TOWARDS THE MORNING. THIS MCS HAS FORMED ON
NORTHERN EDGE OF INSTABILITY GRADIENT WHICH EXTENDS FROM THE
NORTHERN GREAT LAKES INTO SOUTHERN NY/PA. BASED ON CORFIDI VECTORS
BEING NORTHWEST AROUND 25-30 KTS EXPECT THIS MCS TO MOVE
SOUTHEASTWARD. LATEST HRRR AND RAP SIMULATED REFLECTIVITY PROGS
TAKE THE COMPLEX SOUTHEASTWARD ACROSS CENTRAL NEW YORK AROUND
SUNRISE. ITS EVOLUTION & TRACK WILL BE MONITORED THIS EVENING FOR
ANY SHIFT NORTHWARD. THOUGH THE ENTIRE NORTH COUNTRY WILL STAND TO
SEE SHOWERS/THUNDERSTORMS TOWARDS MORNING DUE TO THE STRONG WARM
ADVECTION & ISENTROPIC LIFT THAT WILL BE TAKING PLACE...I SUSPECT
THE BEST CHANCE AT THUNDERSTORMS WOULD BE FOR OUR SOUTHWESTERN CWA
AREAS /FROM AN OGDENSBURG-SARANAC LAKE-NEWCOMB LINE/. I HAVE
RAISED POPS ACCORDINGLY IN THE ADIRONDACKS AND SOUTHERN SAINT
LAWRENCE COUNTY TO BETTER REFLECT ABOVE REASONING. UNTIL
THEN...EXPECT SKIES TO CONTINUE TO FILL IN WITH TEMPERATURES
LEVELING OFF BEFORE RISING TOWARDS MORNING.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH THURSDAY/...
AS OF 325 PM EDT MONDAY...ACTIVE PERIOD OF WEATHER CONTINUES ON
TUESDAY...WITH THE POTENTIAL FOR A FEW STRONG-SEVERE
THUNDERSTORMS. MORNING SHOWERS/TSTORMS ASSOCIATED WITH STRONG WAA
AND CONVECTIVE COMPLEX SHOULD PUSH EAST OF THE REGION BY AROUND
15Z. AT THE SAME TIME THE SURFACE WARM FRONT WILL LIFT
NORTHEASTWARD AND BE DRAPED ACROSS THE AREA...LIKELY BISECTING
THE REGION. THE POSITION OF THIS WARM FRONT IS QUITE CRITICAL FOR
ANY SEVERE CONVECTIVE THREAT. ON SOUTH SIDE OF FRONT...EXPECTING
AT LEAST PARTIAL CLEARING LEADING TO DEVELOPMENT OF 1000-2000
J/KG OF MLCAPE BY LATE WEDNESDAY. THIS COMBINED WITH NEAR 50
KNOTS OF 0-6KM SHEAR AND 20-30 KNOTS OF 0-1KM SHEAR WILL LEAD TO
A CONDITIONAL THREAT OF SEVERE WEATHER. FORECAST SOUNDINGS FOR
TUESDAY AFTERNOON AT BTV/SLK/OGS SHOW CAPPING INVERSION LIMITING
OVERALL CONVECTIVE INITIATION. THUS WILL BE RELYING ON RELATIVELY
WEAK FORCING WITH POSSIBLE LEFTOVER BOUNDARIES FROM EARLY MORNING
CONVECTION OR THE WARM FRONT ITSELF. ON THE COOLER NORTH SIDE OF
BOUNDARY...ANY CONVECTIVE ACTIVITY IS LIKELY TO BE MORE ELEVATED
IN NATURE. THAT ALL BEING SAID...CURRENT THINKING IS THAT WARM
FRONT WILL BE SITUATED FROM THE SAINT LAWRENCE VALLEY ACROSS THE
ADIRONDACKS AND INTO THE CHAMPLAIN VALLEY...WITH THE BEST THREAT
OF ISOLATED SEVERE WEATHER FROM THE CHAMPLAIN VALLEY WESTWARD
ACROSS THE ADIRONDACKS AND INTO THE SAINT LAWRENCE VALLEY WHERE
CONVERGENCE MAY BE ENHANCED BY NORTHEAST FLOW DOWN THE NORTHERN
SAINT LAWRENCE VALLEY. WHILE COVERAGE IS EXPECTED TO BE
LIMITED...ANY THUNDERSTORM THAT MAY DEVELOP ALONG THE WARM FRONT
HAS THE POTENTIAL TO BECOME SEVERE WITH LARGE HAIL...DAMAGING
WINDS...HEAVY RAIN...AND A VERY LOW CHANCE OF A TORNADO.
OTHERWISE...HIGHS WILL ALSO BE VERY DEPENDENT ON POSITION OF WARM
FRONT WITH LOW 80S ON THE WARM SIDE AND LOW 70S ON THE COOL SIDE.
SYNOPTIC WIND GUSTS OUTSIDE OF THUNDERSTORM ACTIVITY WILL LIKELY
REACH 20-30 MPH ON WARM SIDE OF FRONT IN PRONOUNCED SOUTHWEST
FLOW.
THE FRONTAL BOUNDARY WILL REMAIN NEAR THE REGION INTO TUESDAY
NIGHT...WITH INSTABILITY REMAINING...ESPECIALLY ALOFT WITH
PRESENCE OF AN ELEVATED MIXED LAYER. THIS COMBINED WITH ABUNDANT
MOISTURE...AS NOTED BY 1.5-2" PRECIPITABLE WATER VALUES...WILL
KEEP THE CHANCE OF SHOWERS/THUNDERSTORMS AROUND THROUGH THE
NIGHT. TEMPERATURES WILL HAVE TROUBLE FALLING...SO LOOKING AT A
LOT OF UPPER 60S AND LOWER 70S.
POTENTIALLY MORE WIDESPREAD STRONG-SEVERE THUNDERSTORMS ARE
POSSIBLE LATER WEDNESDAY. THE WEAK BOUNDARY WILL REMAIN NEAR THE
REGION...AND FORCING WILL BE ENHANCED BY THE APPROACH OF AN UPPER
TROUGH FROM THE WEST...ESPECIALLY LATER WEDNESDAY AND INTO
WEDNESDAY NIGHT. THE AREA IS EXPECTED TO BE LARGELY INTO THE WARM
SECTOR WITH WIDESPREAD 80S FOR HIGHS...POSSIBLY EVEN A SPOT 90F
IN THE CHAMPLAIN VALLEY. THIS COUPLED WITH DEW POINTS IN THE
UPPER 60S TO NEAR 70 WILL PRODUCE A VERY UNSTABLE AIRMASS WITH
UPWARDS OF 2000 J/KG OF MLCAPE. SHEAR PROFILES STILL LOOK VERY
FAVORABLE FOR STRONG-SEVERE THUNDERSTORM DEVELOPMENT WITH 40-50
KNOTS OF 0-6KM SHEAR ANTICIPATED. 0-1KM SHEAR VALUES ARE
SIGNIFICANTLY LOWER THAN TUESDAY...WITH MAIN POTENTIAL IMPACTS
BEING LARGE HAIL AND DAMAGING WINDS. GREATEST THREAT OF SEVERE
THUNDERSTORMS SHOULD BE 21Z-03Z. GIVEN HIGH MOISTURE
CONTENT...HEAVY RAIN AND MINOR FLOODING WILL BE POSSIBLE IN ANY
THUNDERSTORMS.
COLD FRONT NEARS THE REGION LATER WEDNESDAY NIGHT WITH POTENTIAL
FOR ELEVATED CONVECTIVE ACTIVITY CONTINUING. STRONG SOUTHWEST FLOW
IS ALSO MAINTAINED SO LOWS IN THE UPPER 60S/LOWER 70S LOOK GOOD
AGAIN.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 403 AM EDT TUESDAY...MDLS BRING SLOW MVG FRNTL BOUNDARY ACROSS
THE REGION THURSDAY NIGHT INTO FRIDAY...FOLLOWED BY UPPER LEVEL
TROUGH INTO SATURDAY MORNING. THIS WILL BE FOLLOWED UP WITH SFC
RIDGE BUILDING EAST FROM THE MIDWEST REGION LATER SATURDAY THRU
THE REST OF THE UPCOMING WEEKEND INTO THE BEGINNING OF NEXT WEEK.
WK FRNT IS EXPECTED TO PUSH SOUTH OUT OF QUEBEC MONDAY FOLLOWED BY
HIGH PRESSURE AGAIN GOING INTO MIDWEEK.
THE FRNTL PASSAGE IN THE BEGINNING PORTION OF THE EXTENDED WILL BE
MAIN WX FEATURE. HIGHEST POPS WILL OCCUR DURING THE OVERNGT HRS
THURSDAY INTO FRIDAY MORNING. -RW(W/ SL CHANCE FOR -TRW THRU 06Z
FRI) WILL TAPER FRIDAY MORNING AS SFC RIDGE/DRIER AIR WORKS INTO SE
ONTARIO. WILL CARRY LIKELY POPS FOR MAINLY E VT/CWA AND TAPER TO
CHANCE OF -RW BFR ENDING EARLY SAT MORNING. SFC WAVE ALONG FRNT WILL
ENHANCE PRECIP LATE BFR ENDING. POSSIBLE FOR CUTOFF UPPER LOW
FORMING IN BASE OF TROUGH BEHIND FRNT. GFS LIGHTER ON RAIN VERSUS
ECMWF...SO WILL KEEP AT SL CHANCE FOR SAT MORNING DUE TO UNCERTAINTY
AND MDL CONSISTENCY. QPF AMTS WILL RANGE FROM 0.10" TO NEAR LOCALLY
0.20" AMTS ESPECIALLY IN E VT.
LOW LEVEL COLDER AIR ON NORTHERLY FLOW AHEAD OF APPROACHING SFC
RIDGE WILL SET UP CWA FOR BLW NORMAL TEMPS FOR THE REMAINDER OF THE
WEEKEND INTO NEXT WEEK. 850/925 TEMPS WILL RANGE FROM 0C TO +4/5C.
THE ARRIVAL OF COLDER AIR AT 850 WILL NOT COINCIDE WITH FRNTL PRECIP
BUT COULD BRING SOME PATCHY FROST OVER WEEKEND AT SPOTS IN HIR ELEV
OF DACKS/NC NE VT. OVERALL HIGHS WILL BE IN THE 60S WITH LOWS IN THE
30S TO MID40S WITH SOME NEAR 50F TOWARDS END OF EXTENDED MONDAY
NIGHT AS BRIEF SSW FLOW SETS UP ALONG FRNT.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
THROUGH 06Z WEDNESDAY...PERIODS OF VFR/MVFR CONDITIONS THRU THE
FORECAST PERIOD AS WARM FRONT MOVES ACROSS THE AREA. CEILINGS WILL
RANGE FROM BKN015-020 UP TO BKN050-100 IN VFR SKY COND. LIGHT
RAIN/FG WILL BRING VSBY DOWN TO 4-6SM AT TIMES FOR MPV/SLK/MSS AND
NO RESTRICTIONS FOR OTHER 3 SITES DUE TO SOUTHERLY WINDS. WINDS
WILL RANGE FROM SE TO SW 5-15KTS W/ GUSTS 20-25KTS AT TIMES
ESPECIALLY IN THE CVLY. SOME TRW COULD DEVELOP LATER TODAY AS FRNT
PUSHES THRU AREA.
OUTLOOK 06Z WEDNESDAY THROUGH SATURDAY...
PRIMARILY VFR...THOUGH PERIODS OF IFR/MVFR VSBYS WITH SCATTERED
SHOWERS AND THUNDERSTORMS AS WARM FRONT MOVES THROUGH REGION
TUESDAY FOLLOWED BY COLD FRONTAL PASSAGE THURSDAY. A FEW OF THE
STORMS MAY BE STRONG TO LOCALLY SEVERE TUESDAY EVENING ALONG THE
INTL BORDER...AND ACROSS THE ENTIRE FCST AREA WEDNESDAY AFTERNOON
AND EVENING. ANY STORMS THAT DO BECOME SEVERE MAY CONTAIN STRONG
TURBULENCE...LARGE HAIL AND STRONG SFC WINDS. THE UPPER LEVEL
TROUGH ASSOCIATED WITH THESE FRONTS WILL MOVE THROUGH
FRIDAY...KEEPING A THREAT OF SHOWERS OVER THE NORTH COUNTRY
THROUGH LATE FRIDAY. SATURDAY HIGH PRESSURE WILL BUILD IN AT THE
SFC.
&&
.EQUIPMENT...
AS OF 719 PM EDT SATURDAY...NOAA WEATHER RADIO STATION WXM 44,
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR DUE TO A DAMAGED ANTENNA. REPLACEMENT PARTS HAVE BEEN
ORDERED AND THE REPAIR WORK HAS NOW BEEN SCHEDULED FOR SEPTEMBER
17-20.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MUCCILLI
NEAR TERM...LOCONTO/MUCCILLI
SHORT TERM...MUCCILLI
LONG TERM...JN
AVIATION...JMG/JN
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BUFFALO NY
149 AM EDT TUE SEP 10 2013
.SYNOPSIS...
A WARM FRONT LIFTING ACROSS THE LOWER GREAT LAKES TONIGHT WILL BRING
A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS LATER TONIGHT THROUGH
EARLY TUESDAY ACROSS MUCH OF THE REGION. THIS WARM FRONT WILL
USHER IN UNSEASONABLY HOT AND MUGGY WEATHER TUESDAY AND
WEDNESDAY. EXPECT SHOWERS AND THUNDERSTORMS TO BREAK OUT WEDNESDAY
NIGHT AND THURSDAY AHEAD OF A COLD FRONT THAT WILL BRING A RETURN
TO MUCH COOLER WEATHER BY THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
RADAR IMAGERY SHOWING AN AREA OF SHOWERS SLOWLY INCREASING OVER
SOUTHERN ONTARIO. EXPECT THIS AREA OF SHOWERS TO CONTINUE TO SLOWLY
INCREASE IN COVERAGE AND INTENSITY OVER THE NEXT FEW HOURS AS WARM
ADVECTION INCREASES.
LATER TONIGHT OUR ATTENTION TURNS TO RAIN POTENTIAL ACROSS A BROADER
AREA. STRONG WARM ADVECTION WILL DEVELOP OVERNIGHT AS A WARM FRONTAL
ZONE OVER THE CENTRAL GREAT LAKES MOVES EAST. THE WARM ADVECTION AND
ISENTROPIC UPGLIDE WILL BE SUPPORTED BY A 35-40 KNOT LOW LEVEL
JET...WHICH WILL AID IN LIFT ACROSS THE WARM FRONTAL BOUNDARY AND
ALSO INCREASE MOISTURE CONVERGENCE OVERNIGHT. MESOSCALE MODEL
GUIDANCE IS TRENDING MORE AGGRESSIVE IN DEVELOPING SHOWERS AND A FEW
THUNDERSTORMS ALONG THE ADVANCING WARM FRONT OVERNIGHT. THE PAST FEW
RUNS OF THE HIGH RESOLUTION RAPID REFRESH /HRRR/ BRINGS AN ORGANIZED
AREA OF CONVECTION ACROSS LAKE ONTARIO AND INTO WESTERN AND CENTRAL
NY AROUND 10Z. THE SPC STORM SCALE ENSEMBLE OF OPPORTUNITY IS ALSO
WETTER AND FARTHER SOUTH THAN OPERATIONAL MODEL GUIDANCE...AND
BRINGS MEASURABLE RAIN INTO MUCH OF THE AREA IN THE 06Z-12Z TIME
FRAME.
THE HRRR GUIDANCE SEEMS TOO SLOW GIVEN UPSTREAM RADAR TRENDS...WITH
SHOWERS ALREADY SPREADING ACROSS THE THUMB OF MICHIGAN AT 2330Z.
TYPICALLY WITH AVERAGE STORM MOTION SHOWERS CAN MAKE IT FROM THE
THUMB TO WESTERN NY IN ABOUT 6 HOURS. ALSO OF NOTE...THE LAST FEW
VISIBLE SATELLITE SHOTS OF THE DAY SHOWED A NICE FIELD OF TEXTURED
CLOUDS ACROSS NORTHERN LOWER MICHIGAN...MARKING AN AREA OF MID LEVEL
ELEVATED INSTABILITY. GIVEN THE UPSTREAM RADAR AND SATELLITE
TRENDS...AM INCLINED TO BUY INTO THE MORE AGGRESSIVE MESOSCALE MODEL
SOLUTIONS FOR LATER TONIGHT.
THE MATURING MCS OVER EASTERN LAKE SUPERIOR WILL ALSO NEED TO BE
WATCHED FOR VERY LATE TONIGHT AND EARLY TUESDAY. IF THIS FEATURE
SURVIVES OVERNIGHT...IT SHOULD START TO TURN RIGHT SOME ALONG THE
INSTABILITY GRADIENT AND ALSO DUE TO THE INCREASING LOW LEVEL JET
AND ITS INFLUENCE ON CORFIDI VECTORS.
WITH THE ABOVE IN MIND...HAVE INCREASED POPS TO LIKELY AFTER
MIDNIGHT AND SPREAD POPS MUCH FARTHER TO THE SOUTH AND WEST...WITH
THE MOST LIKELY TRACK OF SHOWERS LATE TONIGHT FROM THE NIAGARA
FRONTIER INTO CENTRAL NY AND THE FINGER LAKES. EXPECT A FEW EMBEDDED
THUNDERSTORMS AS WELL WITH LOCALLY HEAVY DOWNPOURS IF THIS
MATERIALIZES.
ANY ONGOING SHOWERS AND THUNDERSTORMS SHOULD LIFT OFF TO OUR
NORTHEAST TUESDAY MORNING...LEAVING WESTERN AND NORTH-CENTRAL NEW
YORK HOT AND RAIN-FREE FOR THE REST OF THE DAY. RAIN-FREE..BUT NOT
DRY HOWEVER AS DEWPOINTS WELL SOAR INTO THE MID TO UPPER 60S. WITH
850MB TEMPS CLIMBING POTENTIALLY AS HIGH AS +22C AND SOUTHERLY
WINDS...LOOK FOR READINGS TO SOAR INTO THE 90S ACROSS MANY
AREAS...POSSIBLY EVEN FLIRTING WITH RECORD HIGHS AT ROCHESTER.
BUFFALO SHOULD BE SPARED THE HOTTEST TEMPERATURES THANKS TO BRISK
ONSHORE SOUTHWESTERLY FLOW...AS WILL THE NORTH COUNTRY...HOWEVER IT
WILL BE UNUSUALLY HOT ELSEWHERE.
REGARDING WINDS FOR TOMORROW...THE CLEARING SKIES AND SOARING
TEMPERATURES WILL ALLOW FOR PLENTY OF MIXING OF THE BOUNDARY
LAYER...AND THIS WILL LEAD TO GUSTY WINDS...PARTICULARLY ACROSS THE
NIAGARA FRONTIER AND ALONG LAKE ERIE WHERE THE STRONGEST WINDS ALOFT
WILL BE. NAM MODEL PROFILES INDICATE THAT GUSTS COULD APPROACH
ADVISORY LEVELS...HOWEVER THEY HAVE CONSTANTLY BEEN THE OUTLIERS ON
THE STRONG SIDE AND FOR NOW WILL SIDE WITH THE WEAKER GFS/ECMWF/GEM
AND MAINTAIN CONTINUITY WITH GUSTS TO AROUND 35 KNOTS.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
IT WILL BE QUITE WARM TO START THIS PERIOD AS A LOW AMPLITUDE SPLIT
FLOW OVER THE LOWER 48 WILL INCLUDE AN ANOMALOUSLY WARM RIDGE THAT
WILL BE PARKED OVER THE SOUTHEASTERN STATES. THIS RIDGE WILL FEATURE
H925 TEMPS OF AT LEAST 20C (+3 STD) FOR THE SECOND DAY IN A ROW FOR
OUR FORECAST AREA...BUT A CHANGE TO MUCH COOLER WEATHER WILL BE ON
THE HORIZON. AS HEAD TOWARDS THE END OF THE WEEK...SIGNIFICANT
AMPLIFICATION WILL TAKE PLACE WITHIN A PHASED UPPER LEVEL FLOW. THIS
WILL PLACE A DEEP TROUGH OVER THE LOWER GREAT LAKES WHICH WILL
RESULT IN BELOW NORMAL TEMPS FOR THE END OF THE WEEK. MORE ON THIS
IN THE LONG TERM PORTION OF THIS DISCUSSION.
ALL OF WESTERN AND NORTH CENTRAL NEW YORK WILL BE POSITIONED DEEP
WITHIN A WARM SECTOR TUESDAY NIGHT...AS A STALLED WARM FRONTAL WILL
BE FOUND IN THE VCNTY OF THE OTTAWA VALLEY. WHILE THERE COULD BE A
SHOWER OR THUNDERSTORM OVER THE NORTH COUNTRY/THOUSAND ISLANDS
REGION EARLY THURSDAY NIGHT...DRY BUT SULTRY CONDITIONS WILL PREVAIL
OVER THE REGION. AFTER AN AFTERNOON OF NEAR RECORD HEAT...H85 TEMPS
OF +22C AND STRONG SOUTHERLY FLOW WILL EASILY HOLD OUR OVERNIGHT
TEMPS SOME 15 TO 20 DEG F ABV NORMAL VALUES WITH MINS NOT FAR 70.
THIS WILL BE FOLLOWED BY ANOTHER HOT AND HUMID DAY ON WEDNESDAY AS A
BROAD SOUTHWESTERLY FLOW WILL KEEP UNSEASONABLY WARM AIR IN PLACE.
H85 TEMPS NEAR 20C WILL ONCE AGAIN SUPPORT AFTERNOON TEMPS IN THE
UPPER 80S TO LOWER 90S IN THE VALLEYS AND LAKE PLAINS...SO WILL ADD
A FEW DEGREES TO CONTINUITY. THIS HEAT WILL COMBINE WITH DEW POINTS
IN THE UPPER 60S TO PROVIDE PLENTY OF FUEL FOR AFTERNOON CONVECTION.
SBCAPES ARE FORECAST TO REACH 1500-2000 J/KG AWAY FROM THE LAKES...
AND WHILE AIRMASSES LIKE THIS ARE TYPICALLY CAPPED...LAPSE RATES OF
8 TO >10 DEG C/KM ARE FORECAST UP THROUGH H6. THIS LARGE AMOUNT OF
INSTABILITY WILL NEED A TRIGGER TO BE REALIZED THOUGH...AND WITHOUT
ANY SYNOPTIC FORCING TO WORK WITH...THE `LIFTING` WILL HAVE TO COME
FROM LOCALIZED OROGRAPHICS OR LAKE BREEZE BOUNDARIES. THIS SHOULD
LIMIT CONVECTION TO AREAS WELL AWAY FROM THE LAKES...WITH THE LOWEST
POPS FOUND OVER THE IAG FRONTIER WHERE THE STABILIZING EFFECTS OF A
SOUTHWEST FLOW WILL BE IN PLACE. WILL THUS REMOVE MENTION OF STORMS
FOR THE IAG FRONTIER FROM CONTINUITY WHILE ADDING A LITTLE ENHANCED
WORDING FOR GUSTY WINDS TO THE STORMS OVER THE SRN TIER AND FINGER
LAKES.
A ROBUST SHORTWAVE OVER WESTERN ONTARIO WEDNESDAY EVENING WILL PUSH
A STRENGTHENING COLD FRONT ACROSS LOWER MICHIGAN AND SOUTHERN
ONTARIO DURING THE COURSE OF THE OVERNIGHT. WHILE THE FIRST OF
WEDNESDAY NIGHT SHOULD BE WARM AND RAIN FREE OVER MUCH OF OUR
REGION...SHOWERS AND THUNDERSTORMS WILL LIKELY DEVELOP OUT OF THE
FRONT BY DAYBREAK THURSDAY WHEN THE BOUNDARY IS FORECAST TO BE OVER
THE LOWER GREAT LAKES.
THE FRONT IS EXPECTED TO BE THROUGH OUR AREA BY EARLY THURSDAY
AFTERNOON WITH NOTABLY DRIER AND COOLER CANADIAN AIR CLEARING OUT
OUR SKIES FROM THE NORTHWEST. WILL TAPER OFF THE POPS ACCORDINGLY
WITH ONLY SLGT CHC POPS REMAINING EAST OF ROCHESTER BY EVENING. IN
TERMS OF TEMPERATURES...WE SHOULD MAX OUT IN THE MID 70S EARLY IN
THE DAY WITH STEADY OR SLOWLY FALLING MERCURY READINGS ANTICIPATED
FOR THE AFTERNOON WHEN DEW POINTS WILL DROP OFF THROUGH THE 50S.
OUR ATTENTION WILL TURN FROM SYNOPTIC TO MESOSCALE THURSDAY NIGHT AS
SEASONABLY CHILLY AIR WILL POUR ACROSS THE LOWER LAKES IN ADVANCE OF
AN EXPANSIVE AREA OF HIGH PRESSURE OVER WESTERN ONTARIO. H85 TEMPS
ARE PROJECTED TO DROP TO ARND 4C BY DAYBREAK FRIDAY...AND WITH A
DEEP CYCLONIC NORTHWEST FLOW IN PLACE...THERE WILL CERTAINLY BE
ENOUGH LAKE INSTABILITY TO SUPPORT SOME LAKE CLOUDINESS...AND
POSSIBLY NUISANCE SHOWERS EAST/SOUTHEAST OF LK ONTARIO. LOW
TEMPERATURES WILL RANGE FROM THE LOWER 50S ACROSS THE LAKE PLAINS TO
THE MID 40S IN THE SRN TIER VALLEYS/EAST OF THE BLACK RIVER VALLEY.
THESE READINGS WILL BE AT LEAST 15 DEG F LOWER THEN PREVIOUS NIGHTS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
TEMPERATURES WILL AVERAGE NEAR TO BELOW NORMAL DURING THIS PERIOD AS
AN AMPLIFIED LONGWAVE PATTERN OVER THE LOWER 48 WILL BREAK DOWN...
LEAVING MORE OF A ZONAL FLOW ACROSS OUR REGION.
A VIGOROUS SHORTWAVE WILL DROP INTO THE BASE OF A LONGWAVE TROUGH
CENTERED OVER THE LOWER GREAT LAKES ON FRIDAY. THIS FEATURE WILL
COUPLE WITH STRONG COLD ADVECTION TO PRODUCE SOME SHOWERS SOUTH OF
LAKE ONTARIO DURING THE MIDDAY AND AFTERNOON...WHILE TEMPERATURES
WILL STRUGGLE TO REACH 60. THE STRONG MID LEVEL FEATURE WILL SWING
OFF ACROSS NEW ENGLAND FRIDAY NIGHT...WHILE STRONG RIDGING WILL
BUILD IN FROM THE UPPER GREAT LAKES. THIS WILL QUICKLY CLEAR OUT ANY
LEFTOVER SHOWER ACTIVITY...ALTHOUGH SOME NUISANCE LAKE DRIVEN
SHOWERS CANNOT BE RULED OUT WITHIN WEAK CYCLONIC FLOW BETWEEN ROC
AND SYR.
BOTH DAYS OF THE WEEKEND WILL THEN BE DOMINATED BY AN EXPANSIVE AREA
OF HIGH PRESSURE THAT WILL BE PARKED OVER THE GREAT LAKES REGION.
WHILE IT WILL BE SEASONABLY COOL ON SATURDAY WITH HIGHS CLOSE TO
60...WEAK WARM ADVECTION DURING THE SECOND HALF OF THE WEEKEND WILL
BOOST DAYTIME TEMPS BY SOME 10 DEGREES FOR SUNDAY. THIS WILL
TRANSLATE INTO READINGS THAT WILL BE RIGHT ON TARGET FOR NORMALS IN
MID SEPTEMBER...WHICH ARE WITHIN A FEW DEGREES OF 70.
CONFIDENCE IN THE FORECAST WILL DROP OFF SIGNIFICANTLY ON MONDAY...
AS THE DETERMINISTIC PACKAGES ARE AT ODDS OVER THE PASSAGE OF THE
NEXT FRONTAL SYSTEM. WILL CARRY SLGT CHC POPS FOR NOW WHILE LEAVING
TEMPS CLOSE TO THOSE FROM SUNDAY.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AT 06Z VFR FLIGHT CONDITIONS WERE COMMON ACROSS THE REGION...WITH
MID LEVEL CLOUDS DIVING SOUTHEASTWARD. EXPECT SOME LOWERING TO MVFR
AND LOWER AS MOISTURE BUILDS AND SHOWERS AND THUNDERSTORMS INCREASE
IN COVERAGE AREA AND CROSS THE REGION.
THROUGH THE EARLY MORNING HOURS A STRONG WARM FRONT WILL CROSS THE
REGION WITH INCREASING COVERAGE OF SHOWERS ACROSS MUCH OF THE
AREA...ALONG WITH A FEW EMBEDDED THUNDERSTORMS. THUNDERSTORMS THIS
MORNING WILL BE MOST LIKELY ACROSS LAKE ONTARIO AND THE EASTERN LAKE
ONTARIO REGION AS AN UPSTREAM MCS CONTINUES TO NEAR THE REGION THIS
MORNING. THIS ACTIVITY WILL BRING BRIEF PERIODS OF MVFR/IFR
CONDITIONS IN ANY OF THE HEAVIER SHOWERS. THE SHOWERS AND ANY
THUNDER WILL END FROM SOUTHWEST TO NORTHEAST TUESDAY MORNING AS THE
WARM FRONT LIFTS NORTHEAST ACROSS THE AREA. ANY LINGERING MVFR/IFR
CONDITIONS ASSOCIATED WITH THE SHOWERS WILL ALSO END.
FOLLOWING THE WARM FRONT...SKIES WILL CLEAR AND WINDS WILL BECOME
RATHER STRONG WITH GUSTS OF AROUND 30 KNOTS LIKELY ACROSS WESTERN NY
FROM KBUF-KIAG-KROC...WITH 20-25 KNOTS ELSEWHERE.
SOME LOW LEVEL WIND SHEAR IS LIKELY TONIGHT AS THE WARM FRONT LIFTS
NORTHEASTWARD AND A 35-40 KNOT LOW LEVEL JET CROSSES THE AREA. WINDS
WILL STILL BE STRONG JUST OFF THE DECK ON TUESDAY...BUT AS SURFACE
WINDS INCREASE THIS WILL ALLEVIATE ANY SHEAR.
WINDS WILL DIMINISH SOME THIS EVENING AS THE LOW PRESSURE WEAKENS
SOME...AND THE PRESSURE GRADIENT RELAXES. THOUGH WE WILL LOSE THE
STRONG GUSTS AND STILL SOUTHWEST WIND AROUND 10 KNOTS AND OCCASIONAL
LIGHT GUSTS WILL BE COMMON.
OUTLOOK...
TUESDAY NIGHT AND WEDNESDAY...VFR.
WEDNESDAY NIGHT AND THURSDAY...MAINLY VFR WITH SHOWERS LIKELY AND A
CHANCE OF THUNDERSTORMS ALONG WITH ASSOCIATED BRIEF MVFR/IFR.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
SATURDAY...VFR.
&&
.MARINE...
RELATIVELY LIGHT WINDS ON THE LAKES THIS EVENING WILL GRADUALLY
STRENGTHEN OVERNIGHT AS A WARM FRONT LIFTS NORTH ACROSS THE REGION.
THIS FRONT WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS...MAINLY
TO THE WATERS OF LAKE ONTARIO...LATER TONIGHT AND INTO TUESDAY
MORNING. EXPECT SOUTHWESTERLY FLOW TO FRESHEN ON TUESDAY AS AN AREA
OF LOW PRESSURE SKIRTS BY TO THE NORTH OF THE LAKES WITH WINDS
STRENGTHENING ENOUGH TO WARRANT SMALL CRAFT ADVISORIES FOR THE
NEARSHORE WATERS OF EASTERN LAKE ERIE/WESTERN LAKE ONTARIO ON
TUESDAY. WINDS WILL ALSO INCREASE TO SMALL CRAFT ADVISORY LEVELS AT
THE NORTHEAST END OF LAKE ONTARIO. THESE WINDS SHOULD RELAX TUESDAY
NIGHT AS THE LOW WEAKENS.
SHOWERS AND THUNDERSTORMS WILL BE A THREAT ONCE AGAIN WEDNESDAY
NIGHT INTO THURSDAY AHEAD OF A COLD FRONT THAT IS EXPECTED TO CROSS
THE LAKES LATER ON THURSDAY...BRINGING ANOTHER CHANCE OF SMALL CRAFT
ADVISORY LEVEL NORTHWESTERLY WINDS.
&&
.CLIMATE...
TUESDAY AND WEDNESDAY A LATE SUMMER AIRMASS WILL SETTLE ACROSS
THE REGION WITH MANY AREAS WELL INTO THE 80S. BELOW ARE THE RECORD
HIGHS...AND RECORD WARM LOWS FOR OUR THREE CLIMATE SITES:
BUFFALO..
TUESDAY HIGH: 90 (1955) LOW: 75 (1983)
WEDNESDAY HIGH: 87 (1952) LOW: 72 (1931)
ROCHESTER..
TUESDAY HIGH: 94 (1897) LOW: 73 (1925)
WEDNESDAY HIGH: 94 (1931) LOW: 71 (1931)
WATERTOWN..
TUESDAY HIGH: 90 (1959) LOW: 70 (1962)
WEDNESDAY HIGH: 89 (1961) LOW: 70 (1961)
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 6 PM EDT THIS
EVENING FOR LEZ020-040-041.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 6 PM
EDT THIS EVENING FOR LOZ030.
SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 8 PM EDT
THIS EVENING FOR LOZ042-043.
SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 6 PM EDT
THIS EVENING FOR LOZ045.
&&
$$
SYNOPSIS...HITCHCOCK/WOOD
NEAR TERM...HITCHCOCK/WOOD
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...THOMAS
MARINE...WOOD
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
102 AM EDT TUE SEP 10 2013
.SYNOPSIS...
THE NEXT COUPLE OF DAYS WILL FEATURE A BRIEF RETURN TO SUMMER
WEATHER BEFORE TEMPERATURES COOL BACK OFF TO MORE FALL-LIKE
LEVELS BY THE END OF THE WEEK AND INTO THE WEEKEND. THERE WILL
ALSO BE SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS FROM LATE
TONIGHT THROUGH THURSDAY...SOME POTENTIALLY STRONG TO
SEVERE...ESPECIALLY LATE WEDNESDAY.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
AS OF 1258 AM EDT TUESDAY...ONLY MINOR ADJUSTMENTS MADE TO HOURLY
PARAMETERS FOR NEXT SEVERAL HOURS BASED ON LATEST OBSERVATIONAL
DATA AND NEAR TERM GUIDANCE. SHOWERS APPROACHING ST LWR VLY...AND
WILL CONTINUE TO MONITOR MCS OVER NORTHERN GRTLKS AS IT MOVES
SEWRD OVRNGHT.
PREVIOUS DISCUSSION...
MOSTLY MINOR TWEAKS MADE TO TEMPERATURES AND DEWPOINTS TO ACCOUNT
FOR LATEST SFC OBSERVATIONS. HOWEVER...AN ELEVATED MCS THAT IS NOW
EXITING LAKE SUPERIOR HAS RESULTED IN SOME MORE SIGNIFICANT
CHANGES TO POPS TOWARDS THE MORNING. THIS MCS HAS FORMED ON
NORTHERN EDGE OF INSTABILITY GRADIENT WHICH EXTENDS FROM THE
NORTHERN GREAT LAKES INTO SOUTHERN NY/PA. BASED ON CORFIDI VECTORS
BEING NORTHWEST AROUND 25-30 KTS EXPECT THIS MCS TO MOVE
SOUTHEASTWARD. LATEST HRRR AND RAP SIMULATED REFLECTIVITY PROGS
TAKE THE COMPLEX SOUTHEASTWARD ACROSS CENTRAL NEW YORK AROUND
SUNRISE. ITS EVOLUTION & TRACK WILL BE MONITORED THIS EVENING FOR
ANY SHIFT NORTHWARD. THOUGH THE ENTIRE NORTH COUNTRY WILL STAND TO
SEE SHOWERS/THUNDERSTORMS TOWARDS MORNING DUE TO THE STRONG WARM
ADVECTION & ISENTROPIC LIFT THAT WILL BE TAKING PLACE...I SUSPECT
THE BEST CHANCE AT THUNDERSTORMS WOULD BE FOR OUR SOUTHWESTERN CWA
AREAS /FROM AN OGDENSBURG-SARANAC LAKE-NEWCOMB LINE/. I HAVE
RAISED POPS ACCORDINGLY IN THE ADIRONDACKS AND SOUTHERN SAINT
LAWRENCE COUNTY TO BETTER REFLECT ABOVE REASONING. UNTIL
THEN...EXPECT SKIES TO CONTINUE TO FILL IN WITH TEMPERATURES
LEVELING OFF BEFORE RISING TOWARDS MORNING.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 325 PM EDT MONDAY...ACTIVE PERIOD OF WEATHER CONTINUES ON
TUESDAY...WITH THE POTENTIAL FOR A FEW STRONG-SEVERE
THUNDERSTORMS. MORNING SHOWERS/TSTORMS ASSOCIATED WITH STRONG WAA
AND CONVECTIVE COMPLEX SHOULD PUSH EAST OF THE REGION BY AROUND
15Z. AT THE SAME TIME THE SURFACE WARM FRONT WILL LIFT
NORTHEASTWARD AND BE DRAPED ACROSS THE AREA...LIKELY BISECTING
THE REGION. THE POSITION OF THIS WARM FRONT IS QUITE CRITICAL FOR
ANY SEVERE CONVECTIVE THREAT. ON SOUTH SIDE OF FRONT...EXPECTING
AT LEAST PARTIAL CLEARING LEADING TO DEVELOPMENT OF 1000-2000
J/KG OF MLCAPE BY LATE WEDNESDAY. THIS COMBINED WITH NEAR 50
KNOTS OF 0-6KM SHEAR AND 20-30 KNOTS OF 0-1KM SHEAR WILL LEAD TO
A CONDITIONAL THREAT OF SEVERE WEATHER. FORECAST SOUNDINGS FOR
TUESDAY AFTERNOON AT BTV/SLK/OGS SHOW CAPPING INVERSION LIMITING
OVERALL CONVECTIVE INITIATION. THUS WILL BE RELYING ON RELATIVELY
WEAK FORCING WITH POSSIBLE LEFTOVER BOUNDARIES FROM EARLY MORNING
CONVECTION OR THE WARM FRONT ITSELF. ON THE COOLER NORTH SIDE OF
BOUNDARY...ANY CONVECTIVE ACTIVITY IS LIKELY TO BE MORE ELEVATED
IN NATURE. THAT ALL BEING SAID...CURRENT THINKING IS THAT WARM
FRONT WILL BE SITUATED FROM THE SAINT LAWRENCE VALLEY ACROSS THE
ADIRONDACKS AND INTO THE CHAMPLAIN VALLEY...WITH THE BEST THREAT
OF ISOLATED SEVERE WEATHER FROM THE CHAMPLAIN VALLEY WESTWARD
ACROSS THE ADIRONDACKS AND INTO THE SAINT LAWRENCE VALLEY WHERE
CONVERGENCE MAY BE ENHANCED BY NORTHEAST FLOW DOWN THE NORTHERN
SAINT LAWRENCE VALLEY. WHILE COVERAGE IS EXPECTED TO BE
LIMITED...ANY THUNDERSTORM THAT MAY DEVELOP ALONG THE WARM FRONT
HAS THE POTENTIAL TO BECOME SEVERE WITH LARGE HAIL...DAMAGING
WINDS...HEAVY RAIN...AND A VERY LOW CHANCE OF A TORNADO.
OTHERWISE...HIGHS WILL ALSO BE VERY DEPENDENT ON POSITION OF WARM
FRONT WITH LOW 80S ON THE WARM SIDE AND LOW 70S ON THE COOL SIDE.
SYNOPTIC WIND GUSTS OUTSIDE OF THUNDERSTORM ACTIVITY WILL LIKELY
REACH 20-30 MPH ON WARM SIDE OF FRONT IN PRONOUNCED SOUTHWEST
FLOW.
THE FRONTAL BOUNDARY WILL REMAIN NEAR THE REGION INTO TUESDAY
NIGHT...WITH INSTABILITY REMAINING...ESPECIALLY ALOFT WITH
PRESENCE OF AN ELEVATED MIXED LAYER. THIS COMBINED WITH ABUNDANT
MOISTURE...AS NOTED BY 1.5-2" PRECIPITABLE WATER VALUES...WILL
KEEP THE CHANCE OF SHOWERS/THUNDERSTORMS AROUND THROUGH THE
NIGHT. TEMPERATURES WILL HAVE TROUBLE FALLING...SO LOOKING AT A
LOT OF UPPER 60S AND LOWER 70S.
POTENTIALLY MORE WIDESPREAD STRONG-SEVERE THUNDERSTORMS ARE
POSSIBLE LATER WEDNESDAY. THE WEAK BOUNDARY WILL REMAIN NEAR THE
REGION...AND FORCING WILL BE ENHANCED BY THE APPROACH OF AN UPPER
TROUGH FROM THE WEST...ESPECIALLY LATER WEDNESDAY AND INTO
WEDNESDAY NIGHT. THE AREA IS EXPECTED TO BE LARGELY INTO THE WARM
SECTOR WITH WIDESPREAD 80S FOR HIGHS...POSSIBLY EVEN A SPOT 90F
IN THE CHAMPLAIN VALLEY. THIS COUPLED WITH DEW POINTS IN THE
UPPER 60S TO NEAR 70 WILL PRODUCE A VERY UNSTABLE AIRMASS WITH
UPWARDS OF 2000 J/KG OF MLCAPE. SHEAR PROFILES STILL LOOK VERY
FAVORABLE FOR STRONG-SEVERE THUNDERSTORM DEVELOPMENT WITH 40-50
KNOTS OF 0-6KM SHEAR ANTICIPATED. 0-1KM SHEAR VALUES ARE
SIGNIFICANTLY LOWER THAN TUESDAY...WITH MAIN POTENTIAL IMPACTS
BEING LARGE HAIL AND DAMAGING WINDS. GREATEST THREAT OF SEVERE
THUNDERSTORMS SHOULD BE 21Z-03Z. GIVEN HIGH MOISTURE
CONTENT...HEAVY RAIN AND MINOR FLOODING WILL BE POSSIBLE IN ANY
THUNDERSTORMS.
COLD FRONT NEARS THE REGION LATER WEDNESDAY NIGHT WITH POTENTIAL
FOR ELEVATED CONVECTIVE ACTIVITY CONTINUING. STRONG SOUTHWEST FLOW
IS ALSO MAINTAINED SO LOWS IN THE UPPER 60S/LOWER 70S LOOK GOOD
AGAIN.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 345 PM EDT MONDAY...COLD FRONT WILL MOVE THROUGH THE NORTH
COUNTRY FROM WEST TO EAST THURSDAY INTO THURSDAY NIGHT...
PRODUCING SHOWERS AND THUNDERSTORMS ACROSS THE AREA. THIS FRONT
WILL EXIT SERN VT EARLY FRIDAY MORNING WITH LINGERING SHOWERS
PSBL AS THE ASSOCIATED UPPER LEVEL TROUGH BRINGS A POTENT
SHORTWAVE THRU THE REGION ON FRIDAY...KEEPING SKIES MOSTLY
CLOUDY. NW-N WINDS WILL INCREASE AT THE SFC WITH TIGHT PRESSURE
GRADIENT IN PLACE AS A RIDGE OF HIGH PRESSURE BUILD OVER THE
GREAT LAKES REGION. COLDER AIR WILL USHER IN ON THE NORTHERLY
FLOW BEHIND THE AFOREMENTIONED COLD FRONT WITH 850MB TEMPS
DROPPING TO 0C-2C BY LATE FRIDAY. THIS WILL BRING THE SLIGHTLY
WARMER THAN NORMAL TEMPS OF M-U70S ON THURSDAY COOLING TO THE
M50S-L60S ON FRIDAY...WITH MIN TEMPS IN THE 30S-L40S.
THE UPPER LEVEL TROUGH WILL EXIT TO THE EAST SOMETIME LATE
SATURDAY INTO EARLY SUNDAY...WITH CLOUDS DECREASING OVER THE AREA
AND RIDGE OF HIGH PRESSURE AT THE SFC SLIDING EAST...CENTERED
OVER SRN NY/NRN PA AREA. THIS WILL BRING SRLY FLOW AND MODERATING
TEMPERATURES TO THE NORTH COUNTRY SUNDAY AND MONDAY. MAX TEMPS
WILL BE IN THE M-U60S AND MIN TEMPS IN THE U30S-U40S.
MODEL GUIDANCE DIVERGES ON SOLNS TOWARD THE END OF THE PERIOD.
HIGH PRESSURE LOOKS TO KEEP THINGS DRY THROUGH AT LEAST SUNDAY
NT/EARLY MONDAY. GFS BRINGS ANOTHER LOW PRESSURE SYSTEM ACROSS
THE ERN GREAT LAKES BY MONDAY AFTN...WITH ANOTHER COLD FRONT
DRAPED TO THE SW BRINGING SHOWERS AND PSBL TSTMS TO END THE
PERIOD. THE 12Z ECMWF KEEPS THE HIGH PRESSURE OVER THE AREA
THROUGH LATE TUESDAY.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
THROUGH 00Z WEDNESDAY...VFR CONDS EXPECTED THROUGH 08-10Z WITH
SCT/BKN HIGH CLOUDS AND LIGHT SOUTHERLY FLOW FROM 3-8 KTS.
EXCEPTION AT KRUT WHERE SOUTHEASTERLY DRAINAGE FLOWS AROUND 10KTS
EXPECTED OVERNIGHT. APPROACH OF STRONG WARM FRONT TOWARD TUESDAY
MORNING WILL BRING A PERIOD OF SCT SHOWERS/ISOLD THUNDER TO MOST
TERMINALS IN THE 08-14Z TIME FRAME. DRY CONDS MAY PREVAIL AT KRUT.
MAINLY VFR AS ACTIVITY PASSES THOUGH SOME BKN/OVC MVFR CIGS
POSSIBLE AT KMSS/KSLK/KMPV THROUGH THE MORNING HOURS ON TUESDAY.
AFTER 16-18Z WARM FRONT SLOWLY LIFTS TO THE INTL BORDER WITH
INCREASINGLY GUSTY SOUTH/SOUTHWESTERLY FLOW. SOME GUSTS TO 25 KTS
POSSIBLE AT KBTV/KPBG. WHILE THREAT CONDITIONAL...NATL STORM
PREDICTION CENTER CONTINUES TO HIGHLIGHT AREA IN SLIGHT RISK OF
SVR WX LATER TOMORROW/TOMORROW EVENING ON THE SOUTHERN SIDE OF THE
FRONT. HAVE KEPT MOST TERMINALS DRY DUE TO UNCERTAINTY OF
CONVECTIVE DEVELOPMENT. PLEASE NOTE HOWEVER THAT IF ANY STORMS CAN
FORM...THREAT OF ISOLD STRONG/SVR WX IS POSSIBLE.
OUTLOOK 00Z WEDNESDAY THROUGH SATURDAY...
PRIMARILY VFR...THOUGH PERIODS OF IFR/MVFR VSBYS WITH SCATTERED
SHOWERS AND THUNDERSTORMS AS WARM FRONT MOVES THROUGH REGION
TUESDAY FOLLOWED BY COLD FRONTAL PASSAGE THURSDAY. A FEW OF THE
STORMS MAY BE STRONG TO LOCALLY SEVERE TUESDAY EVENING ALONG THE
INTL BORDER...AND ACROSS THE ENTIRE FCST AREA WEDNESDAY AFTERNOON
AND EVENING. ANY STORMS THAT DO BECOME SEVERE MAY CONTAIN STRONG
TURBULENCE...LARGE HAIL AND STRONG SFC WINDS. THE UPPER LEVEL
TROUGH ASSOCIATED WITH THESE FRONTS WILL MOVE THROUGH
FRIDAY...KEEPING A THREAT OF SHOWERS OVER THE NORTH COUNTRY
THROUGH LATE FRIDAY. SATURDAY HIGH PRESSURE WILL BUILD IN AT THE
SFC.
&&
.EQUIPMENT...
AS OF 719 PM EDT SATURDAY...NOAA WEATHER RADIO STATION WXM 44,
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR DUE TO A DAMAGED ANTENNA. REPLACEMENT PARTS HAVE BEEN
ORDERED AND THE REPAIR WORK HAS NOW BEEN SCHEDULED FOR SEPTEMBER
17-20.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MUCCILLI
NEAR TERM...LOCONTO/MUCCILLI
SHORT TERM...MUCCILLI
LONG TERM...KGM
AVIATION...JMG/KGM
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1143 PM CDT MON SEP 9 2013
.UPDATE...
ISSUED AT 1143 PM CDT MON SEP 9 2013
MADE FURTHER ADJUSTMENTS TO POPS AS A LINE OF THUNDERSTORMS MOVES
THROUGH THE DEVILS LAKE AREA TONIGHT. THINK THERE WILL CONTINUE TO
BE A WEAKENING TREND BUT KEPT POPS IN THE LIKELY TO HIGH CHANCE
RANGE FOR A WHILE FOR THE NORTHWEST TO NORTH CENTRAL COUNTIES.
THINK THAT THE SHORTWAVE WILL CONTINUE TO PRODUCE LIFT AND PRECIP
ALTHOUGH INSTABILITY WILL BE LACKING AS WE CONTINUE THROUGH THE
NIGHT.
UPDATE ISSUED AT 931 PM CDT MON SEP 9 2013
BUMPED UP POPS INTO THE 50-60 PERCENT RANGE IN THE DEVILS LAKE
BASIN FOR THE REST OF THE EVENING AS THE LINE OF STORMS OVER NORTH
CENTRAL ND HAS HELD TOGETHER. NAM AND HRRR HAVE THE STORMS
CONTINUING THROUGH THE DEVILS LAKE BASIN BEFORE DIMINISHING AS
THEY MOVE FURTHER EAST. THINK THAT THERE WILL BE SOME WEAKENING
AND DISSIPATING AS THE LINE MOVES FURTHER EAST INTO STABLE AIR
OVER THE NORTHERN RED RIVER VALLEY SO KEPT POPS AROUND 30-40
ACROSS THE REST OF THE NORTHERN FORECAST AREA.
A FEW SPOTS HAVE LOWERED IN VISIBILITY THIS EVENING...BUT NO DENSE
FOG YET. WILL CONTINUE JUST TO KEEP A PATCHY MENTION FOR NOW AS
WITH WINDS SHIFTING WEST BEHIND THE WEAK SFC TROUGH THERE SHOULD
BE SOME MIXING AND SLIGHTLY DRIER AIR MOVING IN.
UPDATE ISSUED AT 629 PM CDT MON SEP 9 2013
RADAR TRENDS SHOW US FAIRLY QUIET FOR THE TIME BEING EXCEPT FOR
SOME LIGHT SHOWERS OR DRIZZLE IN SOME SPOTS. CONVECTION OUT IN
NORTHWESTERN ND IS ON TRACK TO MOVE INTO THE NORTHWESTERN COUNTIES
LATER ON THIS EVENING. HOWEVER...THE NAM AND HRRR SHOW THE
ACTIVITY DISSIPATING BEFORE GETTING VERY FAR INTO OUR AREA. A FEW
OF THE OTHER SOLUTIONS KEEP SOME PRECIP MOVING IN...BUT GIVEN THE
LACK OF EVEN ELEVATED INSTABILITY AM NOT OPTIMISTIC. CONTINUED TO
KEEP 30-40 POPS GOING IN THE NORTH FOR ANYTHING HOLDING TOGETHER
AS THE SHORTWAVE MOVES EAST THIS EVENING BUT WILL HOLD OFF ON ANY
RAISING OR LOWERING OF POPS AT THIS POINT.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 300 PM CDT MON SEP 9 2013
THE GFS IS DOING THE BEST JOB INITIALIZING THE CURRENT DEFORMATION
RAIN BAND...SO WILL UTILIZE THIS SOLUTION WITH NO MODEL DOING VERY
WELL OF LATE.
FOR TONIGHT...EXPECT SHOWERS AND A FEW STORMS MAINLY IN THE
NORTHERN 1/3 OF THE AREA. A FEW STORMS COULD EVEN BE STRONG TO
PERHAPS LOCALLY SEVERE IN THE DVL BASIN...WITH LARGE HAIL
POSSIBLE/STRONG IF SOME INSOLATION DEVELOPS LATE THIS AFTERNOON.
THERE IS ALSO SOME LINGERING INSTABILITY IN THE SOUTH AND EAST
THROUGH THIS EVENING AHEAD OF THE SFC BOUNDARY...SO A FEW STRONG
STORMS ALSO POSSIBLE THERE. SINCE THIS AREA HAS BEEN UNDER CLOUDS
ALL DAY...NOT ANTICIPATING TOO MUCH WIDESPREAD ACTIVITY HERE EITHER.
THERE SHOULD ALSO BE PATCHY FOG IN ALL AREAS TONIGHT...GIVEN VERY
HIGH LOW LEVEL MOISTURE. IF AREAS CLEAR OUT MORE LATER
TONIGHT...THEN FOG COULD BECOME LOCALLY DENSE BUT EXPECTING CLOUDS
TO REMAIN IN MOST AREAS TONIGHT.
ON TUE...THE UPPER WAVE WILL MOVE SLOWLY EAST AND THERE COULD BE A
FEW SHOWERS/STORMS MAINLY IN THE NORTH. TEMPS WILL BE A BIT WARMER
THAN TODAY WITH MORE SUNSHINE.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON SEP 9 2013
FOR WED/THU...EXPECT DRY AND COOL WEATHER WITH HIGH PRESSURE
BUILDING INTO THE REGION. THERE WILL ALSO BE PLENTIFUL SUNSHINE
WITH DEEP LAYERED SUBSIDENCE AND A DRY AIRMASS IN PLACE...SO IT
WILL BE COOL OVERNIGHT.
THURSDAY NIGHT THROUGH MONDAY...12 UTC GFS/ECMWF IN GOOD AGREEMENT
THROUGH 00 UTC SATURDAY...DIVERGING THEREAFTER WITH INTERACTION
BETWEEN A HUDSON BAY TROUGH AND A STAGNANT GREAT BASIN CLOSED LOW.
GENERAL SYNOPTIC IDEA SHOWS A CANADIAN TROUGH MOVING INTO HUDSON
BAY BY 00 UTC SUNDAY AND IN THE PROCESS ENVELOPES A CLOSED LOW
ACROSS THE CENTRAL ROCKIES. WITH THIS PATTERN...TWO POTENTIAL AREAS
OF PRECIPITATION COULD DEVELOP ACROSS THE FORECAST AREA ON SATURDAY.
THE FIRST IS ASSOCIATED WITH THE CANADIAN COLD FRONT DROPPING SOUTH
AND THE SECOND IS FROM WARM AIR ADVECTION ASSOCIATED WITH THE CLOSED
LOW TO THE SOUTH. THE ECMWF IS MOST BULLISH WITH PRECIPITATION FROM
THE SOUTH...WHEREAS THE GFS/DGEX/GEM ARE FARTHER SOUTH AND DRIER
ACROSS THE FORECAST AREA. WILL COVER THIS IN THE GRIDS WITH CHANCE
POPS SPREADING FROM WEST TO EAST FRIDAY NIGHT THROUGH SATURDAY
NIGHT. REST OF THE PERIOD SHOULD BE DRY WITH SURFACE HIGH PRESSURE
ACROSS THE REGION. TEMPERATURES WILL BE MUCH CLOSER TO SEASONAL
NORMALS WITH HIGHS FROM THE MID 60S TO LOWER 70S AND LOWS FROM THE
MID 40S TO MID 50S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1143 PM CDT MON SEP 9 2013
THE NORTHEASTERN TAF SITES HAVE STAYED MVFR AND LOWER WHILE KFAR
AND KDVL HAVE SEEN SOME IMPROVEMENT TO VFR. STORMS MOVING THROUGH
THE KDVL AREA WILL BE THROUGH BY THE TIME THE 06Z TAFS COME INTO
EFFECT. THERE WILL BE A LOT OF LOW LEVEL MOISTURE TONIGHT
PARTICULARLY IN THE NORTHERN COUNTIES WHICH WILL SEE THE MOST
RECENT RAIN. THINK THAT VIS GOING DOWN TO 3-5SM IS POSSIBLE...WITH
SOME MODEL GUIDENCE SHOWING KBJI DOWN TO LESS THAN 1SM. WILL KEEP
AN EYE ON IT BUT JUST WENT 1SM FOR NOW. MVFR CIGS HAVE ALREADY
ENTERED NORTHWESTERN ND AND WILL CONTINUE TO MOVE THROUGH OUR
NORTHERN COUNTIES SO CONDITIONS SHOULD GO BACK DOWN AT KDVL. THINK
THAT KFAR HAS THE BEST CHANCE OF STAYING VFR. CONDITIONS SHOULD
IMPROVE AT ALL TAF SITES BY LATE MORNING...ALTHOUGH SOME MVFR
COULD HANG ON A BIT LONGER AT KBJI.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...DK
LONG TERM...DK/ROGERS
AVIATION...JR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
440 AM EDT TUE SEP 10 2013
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE HOT AND HUMID CONDITIONS THROUGH
WEDNESDAY. A COLD FRONT WILL PUSH THROUGH ON THURSDAY WITH
SHOWERS AND THUNDERSTORMS. MUCH COOLER AIR WILL SETTLE IN BEHIND
THE FRONT FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AREA WILL BE UNDER A HOT AND HUMID SOUTHWEST FLOW BETWEEN HIGH
PRESSURE CENTERED OVER THE CAROLINAS AND LOW PRESSURE PUSHING
ACROSS SOUTHERN CANADA. THERE IS LITTLE FORCING FOR OUR AREA IN
THIS REGIME...THOUGH ISOLATED THUNDERSTORMS WILL BE POSSIBLE THIS
AFTERNOON IN A MODERATELY UNSTABLE ENVIRONMENT.
HIGH TEMPERATURES IN THE LOWER 90S WILL COMBINE WITH DEW POINTS
IN THE UPPER 60S TO PRODUCE HEAT INDICES IN THE UPPER
90S...APPROACHING CRITERIA FOR HEAT ADVISORY, WILL ISSUE SPS TO
HIGHLIGHT HEAT PROBLEMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
PARTLY CLOUDY AND DRY WEATHER IS EXPECTED FOR TONIGHT. ON
WEDNESDAY...HIGH PRESSURE WILL WEAKEN IN RESPONSE TO SHORT WAVE
ENERGY. THUNDERSTORMS WILL BE POSSIBLE WEDNESDAY AFTERNOON AS THE
SHORT WAVE ENERGY INTERACTS WITH THE PERSISTENTLY UNSTABLE
AIRMASS. CLOUD FORMATION MAY ALLOW TEMPERATURES TO STAY A FEW
DEGREES COOLER ON WEDNESDAY...WITH HIGHS AROUND 90.
AN EAST-WEST ORIENTED COLD FRONT WILL BE DROPPING FROM THE GREAT
LAKES LATE WEDNESDAY NIGHT...BEFORE CROSSING THE AREA ON THURSDAY.
THIS WILL BRING THE LIKELIHOOD FOR SHOWERS AND THUNDERSTORMS.
THERE WILL BE MODERATE SHEAR AND INSTABILITY ALONG AND AHEAD OF
THE FRONT...BUT THE FRONT ARRIVING BEFORE PEAK HEATING MAY REDUCE
THE CHANCE FOR SEVERE THUNDERSTORMS. COLD ADVECTION...CLOUDS AND
PRECIP WILL ALLOW FOR HIGHS IN THE 80S ON THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
COLD FRONT WILL CLEAR THE REGION BY THURSDAY NIGHT.
HIGH PRESSURE WILL BUILD ACROSS THE REGION FRIDAY THROUGH SUNDAY.
TEMPERATURES WILL DROP BELOW NORMAL INITIALLY. BUT THEN READINGS
SHOULD REBOUND CLOSER TO SEASONAL AVERAGE BY SUNDAY AS SOUTHERLY
FLOW RETURNS ON THE BACK SIDE OF THE HIGH. UNCERTAINTY INCREASES ON
MONDAY AS 12Z MODELS DIVERGE ON WHETHER ANOTHER COLD FRONT WILL PUSH
INTO THE REGION. AT THIS POINT HAVE SIDED WITH 12Z GEFS MEAN WHICH
IS NOT TOO FAR FROM WPC GUIDANCE.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
MID LEVEL RIDGE TO BUILD EAST BECOMING CENTERED OVER THE TN VLY
TODAY. IN THE MOIST SRLY FLOW...SATL IMGRY SHOWING THE DEVELOPMENT
OF CLOUDS BETWEEN 5000 AND 7000 FEET. LATEST RAP MODEL SHOWS THIS
INCREASE IN LOW LEVEL RH GENERALLY ALONG AND SOUTHEAST OF I-71.
THESE CLOUDS WILL BE BROKEN AT TIMES AND WILL MITIGATE THE
DEVELOPMENT OF WIDESPREAD FOG. THEREFORE...HAVE LIMITED MENTION OF
VSBY RESTRICTION TO MVFR FOR A FEW HOURS PRIOR TO SUNRISE AT
KCVG/KLUK...KILN AND KLCK.
VFR CONDITIONS WITH FEW TO SCT CU AND SOUTHWEST WINDS AROUND 10 KT
ARE EXPECTED DURG THE DAY ON TUESDAY. FROM THE LATE MORNING
THROUGH THE EARLY EVENING. ISOLATED SHOWERS AND THUNDERSTORMS MAY
OCCUR DURING THE AFTERNOON AND EARLY EVENING. HOWEVER...THE LACK
OF FORCING AND MID LEVEL RIDGE IN PLACE WILL LIMIT COVERAGE.
THEREFORE...WILL KEEP THE MENTION OF PRECIPITATION OUT OF THIS TAF
PACKAGE.
OUTLOOK...THUNDERSTORMS POSSIBLE WEDNESDAY NIGHT INTO THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...CONIGLIO
SHORT TERM...CONIGLIO
LONG TERM...
AVIATION...AR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
113 AM EDT TUE SEP 10 2013
.SYNOPSIS...
HOT AND HUMID CONDITIONS WILL BE PRESENT THROUGH WEDNESDAY. A COLD
FRONT WILL MOVE THROUGH THE REGION WEDNESDAY NIGHT INTO THURSDAY.
HIGH PRESSURE WILL BUILD INTO THE AREA FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A WARM AND HUMID AIRMASS REMAINS IN PLACE TONIGHT WITH HIGH
PRESSURE CENTERED TO OUR SOUTH. MOST CLOUD COVER HAS DISSIPATED
ACROSS OUR AREA THIS EVENING AND MOSTLY CLEAR SKIES ARE EXPECTED
OVERNIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
EXPECT TUESDAY TO BE THE WARMEST DAY OF THE WEEK WITH TEMPERATURES
ACROSS THE FA IN THE LOWER 90S. HEAT INDEX VALUES WILL BE IN THE
MIDDLE AND UPPER 90S WHICH IS JUST BELOW HEAT ADVISORY CRITERIA.
WILL CONTINUE TO MENTION THE HEAT IN THE HWO. THERE IS A SLIGHT
CHANCE FOR A COUPLE OF ISOLATED THUNDERSTORMS DURING THE DAYTIME
HOURS ON TUESDAY ACROSS THE SOUTHERN HALF OF THE FA WITH THE
UNSTABLE AIRMASS. EXPECT ANY THUNDERSTORM ACTIVITY TO DECREASE
DURING THE EVENING HOURS ON TUESDAY AND FOR DRY CONDITIONS TO
CONTINUE THROUGH THE NIGHT TUESDAY NIGHT.
ADDITIONAL THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE DURING THE
DAYTIME HOURS ON WEDNESDAY. EXPECT MORE THUNDERSTORM ACTIVITY ON
WEDNESDAY THAN ON TUESDAY. ADDITIONAL CLOUD COVER AND
PRECIPITATION ON WEDNESDAY WILL KEEP TEMPERATURES A COUPLE OF
DEGREES COOLER ON WEDNESDAY THAN ON TUESDAY. THIS THUNDERSTORM
ACTIVITY WILL DECREASE DURING BY SUNSET HOWEVER ADDITIONAL
THUNDERSTORMS WILL BE EDGING TOWARDS THE AREA AS A COLD FRONT
APPROACHES THE REGION. ADDITIONAL THUNDERSTORM ACTIVITY WILL
SPREAD INTO THE FA WEDNESDAY NIGHT WITH THE BEST CHANCE OF
PRECIPITATION ACROSS NORTHERN PORTIONS OF THE FA.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
COLD FRONT WILL CONTINUE PUSHING THROUGH THE REGION THURSDAY.
SOMEWHAT UNCERTAIN HOW EXTENSIVE CONVECTION WILL BE WITH THE
BOUNDARY. THERE IS SOME INDICATION THAT THERE COULD BE WEAKENING IN
THE MORNING AND THEN REDEVELOPMENT IN THE AFTERNOON. THIS WILL ALL
CLEAR THE REGION BY THURSDAY NIGHT.
HIGH PRESSURE WILL BUILD ACROSS THE REGION FRIDAY THROUGH SUNDAY.
TEMPERATURES WILL DROP BELOW NORMAL INITIALLY. BUT THEN READINGS
SHOULD REBOUND CLOSER TO SEASONAL AVERAGE BY SUNDAY AS SOUTHERLY
FLOW RETURNS ON THE BACK SIDE OF THE HIGH. UNCERTAINTY INCREASES ON
MONDAY AS 12Z MODELS DIVERGE ON WHETHER ANOTHER COLD FRONT WILL PUSH
INTO THE REGION. AT THIS POINT HAVE SIDED WITH 12Z GEFS MEAN WHICH
IS NOT TOO FAR FROM WPC GUIDANCE.
&&
.AVIATION /05Z TUESDAY THROUGH SATURDAY/...
MID LEVEL RIDGE TO BUILD EAST BECOMING CENTERED OVER THE TN VLY
TODAY. IN THE MOIST SRLY FLOW...SATL IMGRY SHOWING THE DEVELOPMENT
OF CLOUDS BETWEEN 5000 AND 7000 FEET. LATEST RAP MODEL SHOWS THIS
INCREASE IN LOW LEVEL RH GENERALLY ALONG AND SOUTHEAST OF I-71.
THESE CLOUDS WILL BE BROKEN AT TIMES AND WILL MITIGATE THE
DEVELOPMENT OF WIDESPREAD FOG. THEREFORE...HAVE LIMITED MENTION OF
VSBY RESTRICTION TO MVFR FOR A FEW HOURS PRIOR TO SUNRISE AT
KCVG/KLUK...KILN AND KLCK.
VFR CONDITIONS WITH FEW TO SCT CU AND SOUTHWEST WINDS AROUND 10 KT
ARE EXPECTED DURG THE DAY ON TUESDAY. FROM THE LATE MORNING
THROUGH THE EARLY EVENING. ISOLATED SHOWERS AND THUNDERSTORMS MAY
OCCUR DURING THE AFTERNOON AND EARLY EVENING. HOWEVER...THE LACK
OF FORCING AND MID LEVEL RIDGE IN PLACE WILL LIMIT COVERAGE.
THEREFORE...WILL KEEP THE MENTION OF PRECIPITATION OUT OF THIS TAF
PACKAGE.
OUTLOOK...THUNDERSTORMS POSSIBLE WEDNESDAY NIGHT INTO THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...NOVAK
NEAR TERM...LATTO
SHORT TERM...NOVAK
LONG TERM...
AVIATION...AR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
256 AM EDT TUE SEP 10 2013
.SYNOPSIS...
A WARM FRONT WILL PUSH THROUGH THE REGION LATER THIS MORNING.
UNSEASONABLY HOT AND HUMID CONDITIONS ARE EXPECTED THROUGH MIDWEEK
WITH SCATTERED SHOWERS AND THUNDERSTORMS. SHARPLY COOLER
CONDITIONS WILL ARRIVE BEHIND A COLD FRONT THURSDAY...WITH BELOW
NORMAL TEMPERATURES FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SFC WARM FRONT PUSHING INTO NORTHWEST PA EARLY THIS MORNING.
INCREASING BOUNDARY LAYER MOISTURE WITH JUST ENOUGH CONVERGENCE TO
MAINTAIN ISOLATED COVERAGE OF LIGHT SHOWERS FROM SOUTHERN ONTARIO
TO THE PA LAKE ERIE SHORELINE. EARLIER ACTIVITY HAS EXITED
EASTWARD AND DWINDLED ACROSS THE SOUTH CENTRAL MOUNTAINS AND
MIDDLE SUSQ RIVER VALLEY...BUT UPSTREAM MOISTURE FLUX WITH AN
AMPLIFYING 850 MB THETA-E RIDGE AND BOUNDARY LAYER CONVERGENCE OVER
ACROSS WRN AND NRN PA WILL KEEP ISOLATED SHOWERS GOING FOR THE
NEXT FEW TO SEVERAL HOURS. NOT ANTICIPATING MUCH MORE THAN TRACE
AMOUNTS IN MOST AREAS.
ANOTHER ISSUE CONCERNS THE POTENTIAL OF FOG IN THE PRE DAWN HOURS.
AREA MOST LIKELY TO SEE SIG VSBY REDUCTIONS WILL BE JUST NORTH OF
THE WARM FRONT ACROSS NE PA. LATEST SREF AND RAP SUPPORT THIS
SCENARIO WITH THE NE COUNTIES SEEING THE HIGHEST PROBS OF LOW VSBY
AND HIGHEST SFC RH/S RESPECTIVELY.
CLOUD COVER AND INCREASING HUMIDITY WILL LEAD TO A MUCH MILDER
NIGHT WITH LOWS RANGING FROM THE U50S ACROSS THE N MTNS...TO BTWN
60-65F ELSEWHERE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 AM WEDNESDAY/...
WARM FRONT SHOULD PUSH NE OF THE ENTIRE AREA BY LATE AM...BRINGING
CLEARING SKIES AND RAPIDLY RISING TEMPS. BASED ON UPSTREAM CONDS THIS
AFTN ACROSS THE UPPER MIDWEST...LOOKS LIKE MID SUMMER HEAT AND
HUMIDITY BY TUE AFTN WITH HIGHS APPROACHING 90F IN MANY LOCATIONS.
AN ISOLATED PM SHOWER OR STORM CANNOT BE RULED OUT BUT WITH MODEL
FCST TEMPS IN THE MID LEVELS TOPPING 10C...THE CAP WILL BE PRETTY
HARD TO BREAK. WILL KEEP POPS OF ONLY ARND 10 PCT.
PARTLY TO MOSTLY CLOUDY SKIES TUESDAY NIGHT WITHIN THE EXTENSIVE
WARM SECTOR...WILL COMBINE WITH A SOUTHERLY LIGHT WIND AND SFC
DEWPOINTS IN THE MID TO UPPER 60S...LEADING TO A MUGGY NIGHT WITH
JUST A SCHC FOR TSRA PERSISTING ACROSS NRN PENN.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
ANOMALOUS UPPER RIDGE TO START THE PERIOD WILL BE DISPLACED BY A
DEEP UPPER TROF DROPPING SOUTHWARD FROM THE NORTHERN TERRITORIES
MID TO LATE WEEK. SFC COLD FRONT TIMING STILL APPEARS TO BE
THURSDAY MORNING...WITH THE CORE OF COLDEST AIR AT 850 MB REACHING
CENTRAL PA BY 12Z SAT. LATEST GUIDANCE SUGGESTS THE 850 MB ZERO
LINE DROPS SOUTH OF THE PA/NY BORDER THIS SATURDAY MORNING AS THE
UPPER TROF CLOSES OFF OVER CENTRAL AND SOUTHERN NEW ENGLAND. THIS
WILL SET THE STAGE FOR IMPRESSIVE DROPOFFS IN TEMPERATURE AFTER
MUCH ABOVE NORMAL MIDWEEK HIGHS VISIT THE COMMONWEALTH.
WEDNESDAY WILL LIKELY BE THE HOTTEST DAY UNTIL LATER NEXT SPRING
OR SUMMER...WITH HIGH TEMPS REACHING INTO THE MID 80S /MTNS/ AND
LOWER 90S ACROSS THE LOWER SUSQ VALLEY.
A PRE-FRONTAL/LEE TROF WILL LIKELY DEVELOP ACROSS THE SUSQ VALLEY
WEDNESDAY...HELPING TO FOCUS THE BEST CHC FOR AT LEAST SCATTERED
AFTERNOON TSRA THERE. ACROSS THE NW...THE FIRST OF TWO SFC CFRONTS
WILL APPROACH LATER IN THE DAY/EVENING...SPARKING A BKN BAND OF
SHOWERS AND SCATTERED TSRA.
A PAIR OF COLD FRONTS WILL MOVES SE ACROSS THE STATE WED NIGHT AND
THURSDAY...WITH ANOTHER ROUND OR TO OF SHOWERS/TSRA. FOR LATE IN
THE WEEK AND OVER THE UPCOMING WEEKEND...A SPRAWLING/COOL CANADIAN
HIGH AND ANOMALOUSLY DEEP UPPER TROUGH WILL MOVE SOUTHEAST FROM
THE GLAKES...BRINGING A RETURN TO MUCH LOWER DEWPOINTS AND BELOW
NORMAL TEMPS.
THE ZERO C 850 MB ISOTHERM /IN THE LATEST...03Z SREF/ WILL MOVE OVER
THE NRN GREAT LAKES REGION THURSDAY...BEFORE DIVING SOUTHEAST TO
MAKE A RARE EARLY SEASON APPEARANCE NEAR THE PA/NY BORDER AND
SOUTHERN NEW ENGLAND COAST FRIDAY INTO EARLY SATURDAY. THESE -2 TO
-3 SIGMA TEMPS AT 850 MB WILL UNDOUBTEDLY LEAD TO WIDESPREAD COLD
AIR STRATO CU WITH LAKE EFFECT AND OROGRAPHICALLY ENHANCED
SHOWERS. WE MAY BE UNDERPLAYING THE AMOUNT OF CLOUDS AND POPS FOR
FRIDAY AND SATURDAY HERE IN CENTRAL AND NRN PENN WITHIN THE
COLD...GUSTY AND WELL-ALIGNED DEEP NWRLY FLOW.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
COMPLEX AVN FCST FOR EARLY THIS MORNING. HIGHEST CONFIDENCE IN
LOW CLOUDS IMPACTING THE ERN TERMINALS WITH MVFR/IFR CIGS. THE WRN
AND CNTRL AIRFIELDS COULD SEE SHALLOW STRATUS AND FOG FORM THRU
THE PREDAWN HOURS...AS LLVL MSTR CONTINUES TO INCREASE ALONG WARM
FNT. BFD IS THE MOST LKLY CANDIDATE FOR IFR GIVEN RESIDUAL MSTR
FROM EARLIER RAIN. SOME HI-RES MDL DATA ALSO WANTS TO DEVELOP AN
AREA OF TSTMS OVER THE LWR LKS AND BRING THEM INTO N-CNTRL PA BY
12Z. WITH NOTHING SIGNIFICANT ON UPSTREAM RADAR AS OF 06Z..WILL
MONITOR RADAR TRENDS CLOSELY AND AMD IF TSTM THREAT BECOMES MORE
DEFINED. AS THE WARM FRONT SHIFTS NORTH OF THE AREA LATER
TODAY...EXPECT A.M. VIS/CIG RESTRICTIONS TO IMPROVE TO VFR FOR
BY LATE MORNING WITH VFR PREVAILING THRU THE AFTN/EVE. VERY WARM
AIR ALOFT WILL MOVE OVER THE AIRSPACE THIS AFTN AND ACT AS A CAP
TO PREVENT/LIMIT DIURNAL CONVECTION. LGT WINDS AND DEWPOINTS IN
THE 60S SHOULD FAVOR AREAS OF FOG OVERNIGHT.
OUTLOOK...
WED...SCT PM TSTM IMPACTS PSBL.
THU...SCT-NMRS TSTM IMPACTS PSBL WITH COLD FROPA.
FRI...MVFR/SCT SHOWERS PSBL N/W...VFR CENTRAL/EAST. BREEZY.
SAT...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD/LA CORTE
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...FITZGERALD/LA CORTE
LONG TERM...DEVOIR/GARTNER/MARTIN
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
207 AM EDT TUE SEP 10 2013
.SYNOPSIS...
A WARM FRONT WILL PUSH THROUGH THE REGION LATER THIS MORNING.
UNSEASONABLY HOT AND HUMID CONDITIONS ARE EXPECTED THROUGH MIDWEEK
WITH SCATTERED SHOWERS AND THUNDERSTORMS. SHARPLY COOLER
CONDITIONS WILL ARRIVE BEHIND A COLD FRONT THURSDAY...WITH BELOW
NORMAL TEMPERATURES FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SFC WARM FRONT PUSHING INTO NORTHWEST PA EARLY THIS MORNING.
INCREASING BOUNDARY LAYER MOISTURE WITH JUST ENOUGH CONVERGENCE TO
MAINTAIN ISOLATED COVERAGE OF LIGHT SHOWERS FROM SOUTHERN ONTARIO
TO THE PA LAKE ERIE SHORELINE. EARLIER ACTIVITY HAS EXITED
EASTWARD AND DWINDLED ACROSS THE SOUTH CENTRAL MOUNTAINS AND
MIDDLE SUSQ RIVER VALLEY...BUT UPSTREAM MOISTURE FLUX WITH AN
AMPLIFYING 850 MB THETA-E RIDGE AND BOUNDARY LAYER CONVERGENCE OVER
ACROSS WRN AND NRN PA WILL KEEP ISOLATED SHOWERS GOING FOR THE
NEXT FEW TO SEVERAL HOURS. NOT ANTICIPATING MUCH MORE THAN TRACE
AMOUNTS IN MOST AREAS.
ANOTHER ISSUE CONCERNS THE POTENTIAL OF FOG IN THE PRE DAWN HOURS.
AREA MOST LIKELY TO SEE SIG VSBY REDUCTIONS WILL BE JUST NORTH OF
THE WARM FRONT ACROSS NE PA. LATEST SREF AND RAP SUPPORT THIS
SCENARIO WITH THE NE COUNTIES SEEING THE HIGHEST PROBS OF LOW VSBY
AND HIGHEST SFC RH/S RESPECTIVELY.
CLOUD COVER AND INCREASING HUMIDITY WILL LEAD TO A MUCH MILDER
NIGHT WITH LOWS RANGING FROM THE U50S ACROSS THE N MTNS...TO BTWN
60-65F ELSEWHERE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
WARM FRONT SHOULD PUSH NE OF THE ENTIRE AREA BY LATE AM...BRINGING
CLEARING SKIES AND RAPIDLY RISING TEMPS. BASED ON UPSTREAM CONDS THIS
AFTN ACROSS THE UPPER MIDWEST...LOOKS LIKE MID SUMMER HEAT AND
HUMIDITY BY TUE AFTN WITH HIGHS APPROACHING 90F IN MANY LOCATIONS.
AN ISOLATED PM SHOWER OR STORM CANNOT BE RULED OUT BUT WITH MODEL
FCST TEMPS IN THE MID LEVELS TOPPING 10C...THE CAP WILL BE PRETTY
HARD TO BREAK. WILL KEEP POPS OF ONLY ARND 10 PCT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
PARTLY TO MOSTLY CLOUDY SKIES TUESDAY NIGHT WITHIN THE EXTENSIVE
WARM SECTOR...WILL COMBINE WITH A SOUTHERLY LIGHT WIND AND SFC
DEWPOINTS IN THE MID TO UPPER 60S...LEADING TO A MUGGY NIGHT WITH
JUST A SCHC FOR TSRA PERSISTING ACROSS NRN PENN.
LIKELY THE HOTTEST DAY UNTIL LATER NEXT SPRING OR SUMMER WILL OCCUR
WEDNESDAY...WITH HIGH TEMPS REACHING INTO THE MID 80S /MTNS/ AND
LOWER 90S ACROSS THE LOWER SUSQ VALLEY.
A PRE-FRONTAL/LEE TROF WILL LIKELY DEVELOP ACROSS THE SUSQ VALLEY
WEDNESDAY...HELPING TO FOCUS THE BEST CHC FOR AT LEAST SCATTERED
AFTERNOON TSRA THERE. ACROSS THE NW...THE FIRST OF TWO SFC CFRONTS
WILL APPROACH LATER IN THE DAY/EVENING...SPARKING A BKN BAND OF
SHOWERS AND SCATTERED TSRA.
THE PAIR OF COLD FRONTS WILL MOVES SE ACROSS THE STATE WED NIGHT AND
THURSDAY...WITH ANOTHER ROUND OR TO OF SHOWERS/TSRA. FOR LATE IN THE
WEEK AND OVER THE UPCOMING WEEKEND...A SPRAWLING/COOL CANADIAN HIGH
AND ANOMALOUSLY DEEP UPPER TROUGH WILL MOVE SOUTHEAST FROM THE
GLAKES...BRINGING A RETURN TO MUCH LOWER DEWPOINTS AND BELOW NORMAL
TEMPS.
THE ZERO C 850 MB ISOTHERM /IN THE LATEST...03Z SREF/ WILL MOVE OVER
THE NRN GREAT LAKES REGION THURSDAY...BEFORE DIVING SOUTHEAST TO
MAKE A RARE EARLY SEASON APPEARANCE NEAR THE PENN/NEW YORK BORDER
AND SOUTHERN NEW ENGLAND COAST FRIDAY INTO EARLY SATURDAY. THESE -2
TO -3 SIGMA TEMPS AT 850 MB WILL UNDOUBTEDLY LEAD TO WIDESPREAD COLD
AIR STRATO CU WITH LAKE EFFECT AND OROGRAPHICALLY ENHANCED SHOWERS.
WE MAY BE UNDERPLAYING THE AMOUNT OF CLOUDS AND POPS FOR FRIDAY AND
SATURDAY HERE IN CENTRAL AND NRN PENN WITHIN THE COLD...GUSTY AND
WELL-ALIGNED DEEP NWRLY FLOW.
SO...IN SUMMARY...THE MAIN STORIES FOR THIS PERIOD WILL BE THE HEAT
TO START...SCATTERED STRONG TO SEVERE STORMS POSSIBLE LATER TUESDAY
AND WEDNESDAY...MAINLY NORTH OF THE REGION/...AND THE UNSEASONABLY
CHILLY AIRMASS TO CLOSE IT OUT.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
COMPLEX AVN FCST FOR EARLY THIS MORNING. HIGHEST CONFIDENCE IN
LOW CLOUDS IMPACTING THE ERN TERMINALS WITH MVFR/IFR CIGS. THE WRN
AND CNTRL AIRFIELDS COULD SEE SHALLOW STRATUS AND FOG FORM THRU
THE PREDAWN HOURS...AS LLVL MSTR CONTINUES TO INCREASE ALONG WARM
FNT. BFD IS THE MOST LKLY CANDIDATE FOR IFR GIVEN RESIDUAL MSTR
FROM EARLIER RAIN. SOME HI-RES MDL DATA ALSO WANTS TO DEVELOP AN
AREA OF TSTMS OVER THE LWR LKS AND BRING THEM INTO N-CNTRL PA BY
12Z. WITH NOTHING SIGNIFICANT ON UPSTREAM RADAR AS OF 06Z..WILL
MONITOR RADAR TRENDS CLOSELY AND AMD IF TSTM THREAT BECOMES MORE
DEFINED. AS THE WARM FRONT SHIFTS NORTH OF THE AREA LATER
TODAY...EXPECT A.M. VIS/CIG RESTRICTIONS TO IMPROVE TO VFR FOR
BY LATE MORNING WITH VFR PREVAILING THRU THE AFTN/EVE. VERY WARM
AIR ALOFT WILL MOVE OVER THE AIRSPACE THIS AFTN AND ACT AS A CAP
TO PREVENT/LIMIT DIURNAL CONVECTION. LGT WINDS AND DEWPOINTS IN
THE 60S SHOULD FAVOR AREAS OF FOG OVERNIGHT.
OUTLOOK...
WED...SCT PM TSTM IMPACTS PSBL.
THU...SCT-NMRS TSTM IMPACTS PSBL WITH COLD FROPA.
FRI...MVFR/SCT SHOWERS PSBL N/W...VFR CENTRAL/EAST. BREEZY.
SAT...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD/LA CORTE
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...FITZGERALD/LA CORTE
LONG TERM...GARTNER/MARTIN
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
111 AM EDT TUE SEP 10 2013
.SYNOPSIS...
A WARM FRONT WILL PUSH THROUGH THE REGION LATER THIS MORNING.
UNSEASONABLY HOT AND HUMID CONDITIONS ARE EXPECTED THROUGH MIDWEEK
WITH SCATTERED SHOWERS AND THUNDERSTORMS. SHARPLY COOLER
CONDITIONS WILL ARRIVE BEHIND A COLD FRONT THURSDAY...WITH BELOW
NORMAL TEMPERATURES FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SFC WARM FRONT PUSHING INTO NORTHWEST PA EARLY THIS MORNING.
INCREASING BOUNDARY LAYER MOISTURE WITH JUST ENOUGH CONVERGENCE TO
MAINTAIN ISOLATED COVERAGE OF LIGHT SHOWERS FROM SOUTHERN ONTARIO
TO THE PA LAKE ERIE SHORELINE. EARLIER ACTIVITY HAS EXITED
EASTWARD AND DWINDLED ACROSS THE SOUTH CENTRAL MOUNTAINS AND
MIDDLE SUSQ RIVER VALLEY...BUT UPSTREAM MOISTURE FLUX WITH AN
AMPLIFYING 850 MB THTE RIDGE AND BOUNDARY LAYER CONVERGENCE OVER
ACROSS WRN AND NRN PA WILL KEEP ISOLATED SHOWERS GOING FOR THE
NEXT FEW TO SEVERAL HOURS. NOT ANTICIPATING MUCH MORE THAN TRACE
AMOUNTS IN MOST AREAS.
ANOTHER ISSUE CONCERNS THE POTENTIAL OF FOG IN THE PRE DAWN HOURS.
AREA MOST LIKELY TO SEE SIG VSBY REDUCTIONS WILL BE JUST NORTH OF
THE WARM FRONT ACROSS NE PA. LATEST SREF AND RAP SUPPORT THIS
SCENARIO WITH THE NE COUNTIES SEEING THE HIGHEST PROBS OF LOW VSBY
AND HIGHEST SFC RH/S RESPECTIVELY.
CLOUD COVER AND INCREASING HUMIDITY WILL LEAD TO A MUCH MILDER
NIGHT WITH LOWS RANGING FROM THE U50S ACROSS THE N MTNS...TO BTWN
60-65F ELSEWHERE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
WARM FRONT SHOULD PUSH NE OF THE ENTIRE AREA BY LATE AM...BRINGING
CLEARING SKIES AND RAPIDLY RISING TEMPS. BASED ON UPSTREAM CONDS THIS
AFTN ACROSS THE UPPER MIDWEST...LOOKS LIKE MID SUMMER HEAT AND
HUMIDITY BY TUE AFTN WITH HIGHS APPROACHING 90F IN MANY LOCATIONS.
AN ISOLATED PM SHOWER OR STORM CANNOT BE RULED OUT BUT WITH MODEL
FCST TEMPS IN THE MID LEVELS TOPPING 10C...THE CAP WILL BE PRETTY
HARD TO BREAK. WILL KEEP POPS OF ONLY ARND 10 PCT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
PARTLY TO MOSTLY CLOUDY SKIES TUESDAY NIGHT WITHIN THE EXTENSIVE
WARM SECTOR...WILL COMBINE WITH A SOUTHERLY LIGHT WIND AND SFC
DEWPOINTS IN THE MID TO UPPER 60S...LEADING TO A MUGGY NIGHT WITH
JUST A SCHC FOR TSRA PERSISTING ACROSS NRN PENN.
LIKELY THE HOTTEST DAY UNTIL LATER NEXT SPRING OR SUMMER WILL OCCUR
WEDNESDAY...WITH HIGH TEMPS REACHING INTO THE MID 80S /MTNS/ AND
LOWER 90S ACROSS THE LOWER SUSQ VALLEY.
A PRE-FRONTAL/LEE TROF WILL LIKELY DEVELOP ACROSS THE SUSQ VALLEY
WEDNESDAY...HELPING TO FOCUS THE BEST CHC FOR AT LEAST SCATTERED
AFTERNOON TSRA THERE. ACROSS THE NW...THE FIRST OF TWO SFC CFRONTS
WILL APPROACH LATER IN THE DAY/EVENING...SPARKING A BKN BAND OF
SHOWERS AND SCATTERED TSRA.
THE PAIR OF COLD FRONTS WILL MOVES SE ACROSS THE STATE WED NIGHT AND
THURSDAY...WITH ANOTHER ROUND OR TO OF SHOWERS/TSRA. FOR LATE IN THE
WEEK AND OVER THE UPCOMING WEEKEND...A SPRAWLING/COOL CANADIAN HIGH
AND ANOMALOUSLY DEEP UPPER TROUGH WILL MOVE SOUTHEAST FROM THE
GLAKES...BRINGING A RETURN TO MUCH LOWER DEWPOINTS AND BELOW NORMAL
TEMPS.
THE ZERO C 850 MB ISOTHERM /IN THE LATEST...03Z SREF/ WILL MOVE OVER
THE NRN GREAT LAKES REGION THURSDAY...BEFORE DIVING SOUTHEAST TO
MAKE A RARE EARLY SEASON APPEARANCE NEAR THE PENN/NEW YORK BORDER
AND SOUTHERN NEW ENGLAND COAST FRIDAY INTO EARLY SATURDAY. THESE -2
TO -3 SIGMA TEMPS AT 850 MB WILL UNDOUBTEDLY LEAD TO WIDESPREAD COLD
AIR STRATO CU WITH LAKE EFFECT AND OROGRAPHICALLY ENHANCED SHOWERS.
WE MAY BE UNDERPLAYING THE AMOUNT OF CLOUDS AND POPS FOR FRIDAY AND
SATURDAY HERE IN CENTRAL AND NRN PENN WITHIN THE COLD...GUSTY AND
WELL-ALIGNED DEEP NWRLY FLOW.
SO...IN SUMMARY...THE MAIN STORIES FOR THIS PERIOD WILL BE THE HEAT
TO START...SCATTERED STRONG TO SEVERE STORMS POSSIBLE LATER TUESDAY
AND WEDNESDAY...MAINLY NORTH OF THE REGION/...AND THE UNSEASONABLY
CHILLY AIRMASS TO CLOSE IT OUT.
&&
.AVIATION /05Z TUESDAY THROUGH SATURDAY/...
ONLY A FEW ADJUSTMENTS BASED ON CURRENT RADAR.
EARLIER DISCUSSION BELOW.
FEW LOWER CLDS AT TIMES EARLIER THIS AFT IN RETURN FLOW.
MAIN THING OVERNIGHT WILL BE A FEW SHOWERS...PERHAPS A
RUMBLE OF THUNDER...AS WARM FRONT MOVES INTO THE AREA. VERY
HOT AIRMASS TO THE WEST...DEWPOINTS QUITE HIGH...THUS WILL
HAVE TO MONITOR FOR NEW STORM DEVELOPMENT TO THE WEST.
WENT WITH VFR CONDITIONS ON TUE. EML TYPE AIRMASS WILL LIKELY
KEEP MID LVL TEMPS WARM ENOUGH TO PREVENT SHOWERS AND STORM
FORMATION...SO LEFT THEM OUT OF THE TAFS FOR NOW.
IT WILL BE BREEZY OUT...ESPECIALLY ACROSS NW PA...GIVEN BLAST
OF HOT AIR FROM THE PLAINS.
SIMILAR CONDITIONS FOR WED...MORE IN THE WAY OF A CHC OF A
SHOWER OR STORM...ESPECIALLY LATE...AS THE COLD FRONT NEARS.
MUCH COOLER AND BREEZY CONDITIONS FOR LATE WEEK...AS HIGH
PRESSURE BUILDS SE FROM CANADA.
OUTLOOK...
WED...SCT PM TSTM IMPACTS PSBL.
THU...SCT-NMRS TSTM IMPACTS PSBL WITH COLD FROPA.
FRI...MVFR/SCT SHOWERS PSBL N/W...VFR CENTRAL/EAST.
SAT...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR/
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...FITZGERALD/LA CORTE
LONG TERM...GARTNER/MARTIN
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
110 PM CDT SUN SEP 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 409 AM CDT SUN SEP 8 2013
COMPLEX OF STORMS ACROSS NORTH CENTRAL SOUTH DAKOTA IS EXPECTED TO
SHIFT EAST THIS MORNING AND MAY SCRAPE THE NORTHERN EDGE OF THE
FORECAST AREA THIS MORNING. APPEARS AS THOUGH STORMS ARE DEVELOPING
BEHIND THE LEADING EDGE OF WARM AIR/THETA-E ADVECTION IN A MORE
UNSTABLE ENVIRONMENT. HI RES MODELS HANDLING THE SHORT TERM
RELATIVELY POORLY...WITH MOTH THE RAP AND THE HRRR SUGGESTING THE
ACTIVITY WOULD REMAIN WELL TO THE NORTH NEAR THE NORTH DAKOTA
BORDER. IN GENERAL...WIND SHEAR APPEARS TO BE FAIRLY WEAK SO AM NOT
ANTICIPATING SEVERE WEATHER THROUGH THE MORNING WITH THIS ACTIVITY
AS IT WORKS EAST.
INCREASING SOUTHERLY FLOW ACROSS THE AREA TODAY WILL LEAD TO ANOTHER
WARM AND HUMID DAY ACROSS THE REGION. HAVE TRIMMED BACK FORECAST
HIGHS IN THE NORTH WITH EXPECTED CONVECTION AND CLOUD COVER LIMITING
HEATING POTENTIAL SOME. WITH 925 HPA WINDS INCREASING TO NEAR 20
KNOTS...SHOULD SEE GUSTY WINDS OF 15-20 KNOTS.
EXPECT WIND GUSTS TO DROP OFF THROUGH THE EVENING...BUT SHOULD BE A
FAIRLY WARM NIGHT ACROSS THE REGION WITH SUSTAINED WINDS REMAINING
IN THE 10-15 KNOT RANGE. MODELS SUGGEST A SECONDARY WARM FRONT WILL
LIFT THROUGH THE REGION AND MAY BECOME THE FOCUSING MECHANISM FOR
ELEVATED STORMS ACROSS SOUTHWEST MINNESOTA AND ADJACENT AREAS. WENT
AHEAD AND INCREASED POPS FOR THIS AREA...WITH THE POTENTIAL FOR A
FEW STORMS TO BE MARGINALLY SEVERE WITH STRONGLY VEERING WIND SHEAR
PROFILES.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 409 AM CDT SUN SEP 8 2013
THE COLD FRONT WILL WORK ITS WAY ACROSS THE CWA MONDAY AFTERNOON
INTO THE OVERNIGHT HOURS. LOOKS LIKE GOOD HEATING POTENTIAL AHEAD OF
THE FRONT...WITH A SOUTHWESTERLY BREEZE GUSTING TO AROUND 30 MPH AND
COMPRESSIONAL HEATING. GIVEN OUR LACK OF GOOD MIXING RECENTLY...WAS
HESITANT TO GO TOO WARM WITH HIGHS...SO WHILE I DID GO HIGHER THAN
THE COOL BIAS CORRECTED VALUES...DID NOT GO WITH FULL MIXING TO 850
MB. FRONTAL TIMING IS STILL A BIT UNCERTAIN...AND THIS WILL HAVE AN
IMPACT ON HIGHS AS WELL. HIGHEST READINGS SHOULD BE ACROSS NORTHWEST
IOWA AND PORTIONS OF SOUTHWEST MINNESOTA...WHERE MID AND A FEW UPPER
90S SEEM PROBABLE. THE MARSHALL TO SIOUX FALLS TO YANKTON CORRIDOR
HAS THE HIGHER UNCERTAINTY...HOWEVER MOST MODEL SOLUTIONS KEEP THE
FRONT SLOW ENOUGH TO ALLOW THESE AREAS TO WARM INTO THE LOW TO MID
90S. CURRENTLY LOOKS LIKE HEAT INDICES WILL BE IN THE MID TO UPPER
90S...BUT SHOULD REMAIN BELOW 100...WITH THE INCREASED MIXING ALSO
HELPING TO LOWER DEWPOINTS SOME AHEAD OF THE FRONT.
LOOKING AT TWO POTENTIAL CHANCES FOR PRECIPITATION WITH THE FRONTAL
PASSAGE. THE PRE FRONTAL ATMOSPHERE SHOULD GENERALLY REMAIN CAPPED
THROUGH THE DAY. HOWEVER...RIGHT ALONG AND JUST BEHIND THE
FRONT...INDICATIONS THAT MOISTURE POOLING WILL RESULT IN AN INCREASE
IN DEWPOINTS. IT IS POSSIBLE THAT THIS...COMBINED WITH
FRONTOGENETICAL FORCING WILL BE ENOUGH TO BREAK THE CAP. IF THIS
HAPPENS IT WOULD LIKELY BE IN THE 21Z TO 03Z TIMEFRAME....GENERALLY
ALONG AND NORTHWEST OF A YANKTON TO WORTHINGTON LINE. THIS IMMEDIATE
POST FRONTAL ATMOSPHERE SHOULD BE CHARACTERIZED BY CAPE AROUND 1500
J/KG AND EFFECTIVE DEEP LAYER SHEAR OF ABOUT 30 KTS. SO WHILE
NOTHING TOO IMPRESSIVE...THESE PARAMETERS ARE ENOUGH TO SUGGEST AN
ISOLATED SEVERE STORM WOULD BE POSSIBLE. THE SECOND THREAT WILL BE
AS THE MAIN UPPER WAVE PASSES TO OUR NORTH. WHILE THE BEST PV
ADVECTION WILL REMAIN NORTH...A 60 TO 80 KT UPPER JET PASSING TO OUR
NORTH WILL PUT US IN FAVORED THE RIGHT ENTRANCE REGION. WHILE THIS
UPPER LEVEL SUPPORT APPEARS TOO LATE TO HELP WITH THE NEAR SURFACED
BASED CONVECTION POTENTIAL DISCUSSED ABOVE...IT MAY INTERACT WITH
THE 700 MB FRONT AND ALLOW FOR THE DEVELOPMENT OF ADDITIONAL SHOWER
AND THUNDERSTORMS FROM ABOUT 06Z ON. BY THIS TIME...MID LEVEL LAPSE
RATES BECOME PRETTY WEAK...AND THUS ELEVATED INSTABILITY WILL BE
LOW. MAYBE ENOUGH TO GET THUNDER...BUT WOULD NOT EXPECT ANYTHING
SEVERE WITH THIS ACTIVITY. WITH PWATS RUNNING 2 TO 3 STANDARD
DEVIATIONS ABOVE NORMAL...AND STORM MOTIONS NEARLY PARALLEL TO THE
MID LEVEL FRONT...LOCALLY HEAVY RAIN WOULD BE POSSIBLE. WILL JUST
KEEP HIGH CHANCE POPS FOR NOW...AS THE OVERNIGHT ACTIVITY WILL
PROBABLY BE PRETTY NARROW AND FOCUSED CLOSE TO THE 700 MB
FRONT...AND UNCERTAINTY EXISTS ON WHERE EXACTLY THIS WILL SET UP.
ALSO SOME MODEL RUNS ARE PRETTY WEAK ON QPF...POSSIBLY DUE TO THE
WEAK INSTABILITY AND A BIT OF A DRY LAYER AROUND 850 MB...SO WHILE
IT LOOKS LIKE A GOOD CHANCE MONDAY NIGHT...WILL CONTINUE TO HOLD OFF
ON LIKELY POPS FOR THE TIME BEING.
MODELS TRENDING TOWARDS STALLING THE FRONT FURTHER SOUTH THAN
PREVIOUSLY THOUGHT. THIS WILL PROBABLY LIMIT THE PRECIP POTENTIAL
TUESDAY INTO TUESDAY NIGHT...BUT WILL KEEP A SMALL POP GOING ACROSS
NORTHWEST IOWA. WE WILL SEE COOLER TEMPERATURES FILTER IN BEHIND THE
FRONT TUESDAY INTO WEDNESDAY AS THE RIDGE FLATTENS. ALTHOUGH STILL
EXPECTING ABOVE NORMAL READINGS IN THE LOW TO MID 80S. DEWPOINTS MAY
LINGER IN THE LOW 60S TUESDAY...BUT SHOULD FINALLY DROP INTO THE 50S
BY WEDNESDAY...BRINGING AN END TO THE HUMID PERIOD. A STRONG WAVE
MOVING ACROSS SOUTHERN CANADA WILL HELP PUSH A A BACKDOOR COLD FRONT
AND EVEN COOLER AND LESS HUMID CONDITIONS INTO THE REGION THURSDAY
INTO FRIDAY. EXPECTING HIGHS IN THE 70S BOTH DAYS...WITH ONLY AREAS
NEAR THE MISSOURI RIVER POTENTIALLY HITTING 80. ALSO WOULD EXPECT
COOLER NIGHTTIME TEMPERATURES WITH HIGH PRESSURE CENTERED TO OUR
NORTHEAST. FRIDAY MORNING CURRENTLY LOOKS TO BE THE
COOLEST...POSSIBLY BEING THE FIRST NIGHT IN A WHILE WHERE LOWS
ACTUALLY END UP BELOW NORMAL...IN THE UPPER 40S TO MID 50S. AS THE
RIDGE BEGINS TO BUILD BACK IN LATER FRIDAY INTO SATURDAY...THE
THUNDERSTORM THREAT SHOULD AGAIN BEGIN TO INCREASE OVER THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1259 PM CDT SUN SEP 8 2013
NEAR TERM CONCERNS ARE STRATUS AND THEN WIND SHAR. A LARGE AREA OF
STRATUS CONTINUES TO TRY TO SPREAD EAST FROM SW MN AND NW IA AND
INTO SE SE. DO HAVE A BREIF PERIOD OF BKN STRATUS EARLY THIS
AFTERNOON AROUD KFSD. HOWEVER...COULD SEE BKN-OVC STRATUS AT KHON
AND KFSD THROUGH MUCH OF THE AFTERNOON AND EVENING AS AMPLE LOW
LEVEL MOISTURE REMAINS TRAPPED BELOW A VERY STRONG INVERSION.
IF STRATUS IS MAINTAINED IT COULD LAST THROUGH 06Z AT BOTH
LOCATIONS.
OVERNIGHT...A STRONG SOUTHWESTERLY LOW LEVEL JET OF 40 TO 50 KTS WILL
DEVELOP AND WITH WINDS AT THE SURFACE SOUTHEAST AROUND 10
KTS...THERE WILL BE SOME LOW LEVEL WIND SHEAR LATER TONIGHT ACROSS
THE AREA. IN ADDITION...ISOALTED THUNDERSTORMS MAY FORM NORTHEAST
OF SIOUX FALLS BUT ANY STORMS ARE NOT EXPECTED TO AFFECT TAF
LOCATIONS. OTHERWISE...A COLD FRONT WILL MOVE INTO SOUTHEAST SOUTH
DAKOTA DURING THE MORNING WITH THE FRONT EXPECTED TO MOVE THROUGH
KHON AROUND 15Z...AND KFSD BETWEEN 18Z AND 20Z. ANY PRECIPITATION
IS EXPECTED TO HOLD OFF UNTIL AFTER 21Z MONDAY WITH THE BEST
CHANCE AFTER 00Z TUESDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...CHENARD
AVIATION...SCHUMACHER
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
635 AM CDT SUN SEP 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 409 AM CDT SUN SEP 8 2013
COMPLEX OF STORMS ACROSS NORTH CENTRAL SOUTH DAKOTA IS EXPECTED TO
SHIFT EAST THIS MORNING AND MAY SCRAPE THE NORTHERN EDGE OF THE
FORECAST AREA THIS MORNING. APPEARS AS THOUGH STORMS ARE DEVELOPING
BEHIND THE LEADING EDGE OF WARM AIR/THETA-E ADVECTION IN A MORE
UNSTABLE ENVIRONMENT. HI RES MODELS HANDLING THE SHORT TERM
RELATIVELY POORLY...WITH MOTH THE RAP AND THE HRRR SUGGESTING THE
ACTIVITY WOULD REMAIN WELL TO THE NORTH NEAR THE NORTH DAKOTA
BORDER. IN GENERAL...WIND SHEAR APPEARS TO BE FAIRLY WEAK SO AM NOT
ANTICIPATING SEVERE WEATHER THROUGH THE MORNING WITH THIS ACTIVITY
AS IT WORKS EAST.
INCREASING SOUTHERLY FLOW ACROSS THE AREA TODAY WILL LEAD TO ANOTHER
WARM AND HUMID DAY ACROSS THE REGION. HAVE TRIMMED BACK FORECAST
HIGHS IN THE NORTH WITH EXPECTED CONVECTION AND CLOUD COVER LIMITING
HEATING POTENTIAL SOME. WITH 925 HPA WINDS INCREASING TO NEAR 20
KNOTS...SHOULD SEE GUSTY WINDS OF 15-20 KNOTS.
EXPECT WIND GUSTS TO DROP OFF THROUGH THE EVENING...BUT SHOULD BE A
FAIRLY WARM NIGHT ACROSS THE REGION WITH SUSTAINED WINDS REMAINING
IN THE 10-15 KNOT RANGE. MODELS SUGGEST A SECONDARY WARM FRONT WILL
LIFT THROUGH THE REGION AND MAY BECOME THE FOCUSING MECHANISM FOR
ELEVATED STORMS ACROSS SOUTHWEST MINNESOTA AND ADJACENT AREAS. WENT
AHEAD AND INCREASED POPS FOR THIS AREA...WITH THE POTENTIAL FOR A
FEW STORMS TO BE MARGINALLY SEVERE WITH STRONGLY VEERING WIND SHEAR
PROFILES.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 409 AM CDT SUN SEP 8 2013
THE COLD FRONT WILL WORK ITS WAY ACROSS THE CWA MONDAY AFTERNOON
INTO THE OVERNIGHT HOURS. LOOKS LIKE GOOD HEATING POTENTIAL AHEAD OF
THE FRONT...WITH A SOUTHWESTERLY BREEZE GUSTING TO AROUND 30 MPH AND
COMPRESSIONAL HEATING. GIVEN OUR LACK OF GOOD MIXING RECENTLY...WAS
HESITANT TO GO TOO WARM WITH HIGHS...SO WHILE I DID GO HIGHER THAN
THE COOL BIAS CORRECTED VALUES...DID NOT GO WITH FULL MIXING TO 850
MB. FRONTAL TIMING IS STILL A BIT UNCERTAIN...AND THIS WILL HAVE AN
IMPACT ON HIGHS AS WELL. HIGHEST READINGS SHOULD BE ACROSS NORTHWEST
IOWA AND PORTIONS OF SOUTHWEST MINNESOTA...WHERE MID AND A FEW UPPER
90S SEEM PROBABLE. THE MARSHALL TO SIOUX FALLS TO YANKTON CORRIDOR
HAS THE HIGHER UNCERTAINTY...HOWEVER MOST MODEL SOLUTIONS KEEP THE
FRONT SLOW ENOUGH TO ALLOW THESE AREAS TO WARM INTO THE LOW TO MID
90S. CURRENTLY LOOKS LIKE HEAT INDICES WILL BE IN THE MID TO UPPER
90S...BUT SHOULD REMAIN BELOW 100...WITH THE INCREASED MIXING ALSO
HELPING TO LOWER DEWPOINTS SOME AHEAD OF THE FRONT.
LOOKING AT TWO POTENTIAL CHANCES FOR PRECIPITATION WITH THE FRONTAL
PASSAGE. THE PRE FRONTAL ATMOSPHERE SHOULD GENERALLY REMAIN CAPPED
THROUGH THE DAY. HOWEVER...RIGHT ALONG AND JUST BEHIND THE
FRONT...INDICATIONS THAT MOISTURE POOLING WILL RESULT IN AN INCREASE
IN DEWPOINTS. IT IS POSSIBLE THAT THIS...COMBINED WITH
FRONTOGENETICAL FORCING WILL BE ENOUGH TO BREAK THE CAP. IF THIS
HAPPENS IT WOULD LIKELY BE IN THE 21Z TO 03Z TIMEFRAME....GENERALLY
ALONG AND NORTHWEST OF A YANKTON TO WORTHINGTON LINE. THIS IMMEDIATE
POST FRONTAL ATMOSPHERE SHOULD BE CHARACTERIZED BY CAPE AROUND 1500
J/KG AND EFFECTIVE DEEP LAYER SHEAR OF ABOUT 30 KTS. SO WHILE
NOTHING TOO IMPRESSIVE...THESE PARAMETERS ARE ENOUGH TO SUGGEST AN
ISOLATED SEVERE STORM WOULD BE POSSIBLE. THE SECOND THREAT WILL BE
AS THE MAIN UPPER WAVE PASSES TO OUR NORTH. WHILE THE BEST PV
ADVECTION WILL REMAIN NORTH...A 60 TO 80 KT UPPER JET PASSING TO OUR
NORTH WILL PUT US IN FAVORED THE RIGHT ENTRANCE REGION. WHILE THIS
UPPER LEVEL SUPPORT APPEARS TOO LATE TO HELP WITH THE NEAR SURFACED
BASED CONVECTION POTENTIAL DISCUSSED ABOVE...IT MAY INTERACT WITH
THE 700 MB FRONT AND ALLOW FOR THE DEVELOPMENT OF ADDITIONAL SHOWER
AND THUNDERSTORMS FROM ABOUT 06Z ON. BY THIS TIME...MID LEVEL LAPSE
RATES BECOME PRETTY WEAK...AND THUS ELEVATED INSTABILITY WILL BE
LOW. MAYBE ENOUGH TO GET THUNDER...BUT WOULD NOT EXPECT ANYTHING
SEVERE WITH THIS ACTIVITY. WITH PWATS RUNNING 2 TO 3 STANDARD
DEVIATIONS ABOVE NORMAL...AND STORM MOTIONS NEARLY PARALLEL TO THE
MID LEVEL FRONT...LOCALLY HEAVY RAIN WOULD BE POSSIBLE. WILL JUST
KEEP HIGH CHANCE POPS FOR NOW...AS THE OVERNIGHT ACTIVITY WILL
PROBABLY BE PRETTY NARROW AND FOCUSED CLOSE TO THE 700 MB
FRONT...AND UNCERTAINTY EXISTS ON WHERE EXACTLY THIS WILL SET UP.
ALSO SOME MODEL RUNS ARE PRETTY WEAK ON QPF...POSSIBLY DUE TO THE
WEAK INSTABILITY AND A BIT OF A DRY LAYER AROUND 850 MB...SO WHILE
IT LOOKS LIKE A GOOD CHANCE MONDAY NIGHT...WILL CONTINUE TO HOLD OFF
ON LIKELY POPS FOR THE TIME BEING.
MODELS TRENDING TOWARDS STALLING THE FRONT FURTHER SOUTH THAN
PREVIOUSLY THOUGHT. THIS WILL PROBABLY LIMIT THE PRECIP POTENTIAL
TUESDAY INTO TUESDAY NIGHT...BUT WILL KEEP A SMALL POP GOING ACROSS
NORTHWEST IOWA. WE WILL SEE COOLER TEMPERATURES FILTER IN BEHIND THE
FRONT TUESDAY INTO WEDNESDAY AS THE RIDGE FLATTENS. ALTHOUGH STILL
EXPECTING ABOVE NORMAL READINGS IN THE LOW TO MID 80S. DEWPOINTS MAY
LINGER IN THE LOW 60S TUESDAY...BUT SHOULD FINALLY DROP INTO THE 50S
BY WEDNESDAY...BRINGING AN END TO THE HUMID PERIOD. A STRONG WAVE
MOVING ACROSS SOUTHERN CANADA WILL HELP PUSH A A BACKDOOR COLD FRONT
AND EVEN COOLER AND LESS HUMID CONDITIONS INTO THE REGION THURSDAY
INTO FRIDAY. EXPECTING HIGHS IN THE 70S BOTH DAYS...WITH ONLY AREAS
NEAR THE MISSOURI RIVER POTENTIALLY HITTING 80. ALSO WOULD EXPECT
COOLER NIGHTTIME TEMPERATURES WITH HIGH PRESSURE CENTERED TO OUR
NORTHEAST. FRIDAY MORNING CURRENTLY LOOKS TO BE THE
COOLEST...POSSIBLY BEING THE FIRST NIGHT IN A WHILE WHERE LOWS
ACTUALLY END UP BELOW NORMAL...IN THE UPPER 40S TO MID 50S. AS THE
RIDGE BEGINS TO BUILD BACK IN LATER FRIDAY INTO SATURDAY...THE
THUNDERSTORM THREAT SHOULD AGAIN BEGIN TO INCREASE OVER THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 628 AM CDT SUN SEP 8 2013
SEVERAL AVIATION ISSUES THIS MORNING. ELEVATED SHOWERS MOVING INTO
THE HURON AREA SHOULD NOT RESULT IN A REDUCTION IN CONDITIONS
BELOW VFR. SHOWERS SHOULD REMAIN NORTH OF THE KFSD TERMINAL.
FURTHER TO THE SOUTH...LOW LYING FOG NEAR THE KSUX TERMINAL IS
EXPECTED TO BURN OFF A FEW HOURS AFTER SUNRISE. SOUTHERLY WINDS
WILL INCREASE THROUGHOUT THE DAY AND BECOME SOMEWHAT GUSTY. THE
LOW LEVEL JET IS EXPECTED TO INCREASE TO 40-50 KNOTS ACROSS THE
FORECAST AREA TONIGHT...AND HAVE ADDED LOW LEVEL WIND SHEAR TO
BOTH KHON AND KFSD TERMINALS. CONSIDERED ALSO ADDING IT TO
KSUX...THOUGH WINDS APPEARED TO BE SOMEWHAT MARGINAL THERE SO
OPTED TO LEAVE OUT FOR NOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...CHENARD
AVIATION...
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1239 AM CDT TUE SEP 10 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 403 PM CDT MON SEP 9 2013
PLENTY OF QUESTIONS REMAIN REGARDING THE CHANCE FOR CONVECTION
TODAY. THERE WERE EVEN A FEW SHOWERS THAT WERE ON THEIR WAY OUT
OF THE AREA AT 20Z THAT APPEAR TO HAVE DEVELOPED ALONG A BOUNDARY
FROM THE THUNDERSTORM COMPLEX THAT MOVED ACROSS MINNESOTA
OVERNIGHT. THERE IS PLENTY OF INSTABILITY...MESOANALYSIS HAD
MUCAPES MAINLY IN THE 1000-3000J/KG RANGE EXCEPT NEAR THE UPPER
MICHIGAN BORDER WHERE THEY WERE IN THE 500-1000J/KG RANGE AT 20Z.
WEAKEST CIN WAS FROM NORTH CENTRAL AND NORTHEAST WISCONSIN
SOUTHWEST INTO EASTERN IOWA...BUT STRONG WARM ADVECTION ALOFT
CONTINUED TO HAMPER CONVECTIVE DEVELOPMENT ACROSS THE AREA.
LIGHT EAST OR SOUTH WINDS THIS MORNING HAVE BECOME SOUTHERLY AND
INCREASED DURING THE DAY. A WARM FRONT WAS MOVING NORTHEAST INTO
CENTRAL WISCONSIN THIS AFTERNOON AND WAS FORECAST TO MAKE IT TO
NEAR THE WISCONSIN/UPPER MICHIGAN BORDER BY 00Z. THIS MAY BE A
BIT TOO QUICK BASED ON ITS SPEED DURING THE DAY. THE WESTERLY FLOW
OF WARM AIR ALOFT WAS HELPING TO PRODUCE STRONG LOW-LEVEL AND
DEEP-LAYER SHEAR...ESPECIALLY ACROSS NORTHERN WISCONSIN AND UPPER
MICHIGAN.
STORMS MAY FIRE AS THE SURFACE LOW IN EASTERN MINNESOTA MOVES
ACROSS NORTHERN WISCONSIN LATER TONIGHT. EXPERIMENTAL COMPOSITE
REFLECTIVITY FROM THE 18Z HRRR DID NOT REALLY SHOW ANYTHING ACROSS
THE AREA...THOUGH IT DID SUGGEST CONVECTIVE ACTIVITY IN
CENTRAL/SOUTHERN WISCONSIN TODAY THAT DID NOT DEVELOP. IF STORMS
DO DEVELOP...THEY COULD PRODUCE LARGE HAIL AND DAMAGING WINDS. AN
ISOLATED TORNADO WAS EVEN MENTIONED BY SPC IN THEIR DAY ONE
OUTLOOK...WITH STORMS DEVELOPING INTO A FORWARD PROPAGATING MCS
WITH LLJ DEVELOPMENT...RESULTING IN MAINLY A DAMAGING WIND EVENT
THEREAFTER.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 403 PM CDT MON SEP 9 2013
LITTLE CHANGE IN SCENARIO FROM PAST FEW DAYS WITH AREA
TRANSITIONING INTO A NORTHWEST FLOW REGIME BY WED. MODELS IN
SIMILAR AGREEMENT THROUGH THE END OF THE WORK WEEK...THEN BEGIN
TO DIFFER AS MORE ZONAL PATTERN BUILDS IN. PRECIPITATION CHANCES
FIRST PART OF FORECAST MAIN CONCERNS.
WEAK COLD FRONT WILL SLOWLY SAG SOUTH THROUGH CWA ON TUE...THEN
SOUTH OF THE REGION TUESDAY NIGHT. MODELS TRENDING DRY THROUGH AM
WITH LIMITED CONVERGENCE ALONG FRONT AND NO UPPER SUPPORT. MODELS
A BIT MORE BULLISH ON QPF CHANCES LATE TUE AFTN AND OVERNIGHT...AS
WEAK WAVE MOVES NORTHEAST ALONG FRONT IN RESPONSE TO SHORT WAVE
TROF AND SOME JET ENERGY MOVING THROUGH. BUMPED POPS UP TO LIKELY
IN THE FAR SOUTH. PW`S STILL IN THE 1.5 TO 2 INCH RANGE WITH HEAVY
RAIN BIGGEST THREAT.
POSSIBILITY OF SHOWERS CONTINUES INTO THU AS UPPER DISTURBANCES
DROP SOUTHEAST THROUGH THE WESTERN LAKES. LINGERING LOW LEVEL
MOISTURE TO LEAD TO BETTER INSTABILITY AND CHANCE OF PCPN ON WED BUT
LATEST RUNS SHOW RATHER STRONG SYSTEM DROPPING THROUGH ON THU.
HAVE STAYED DRY THU ATTM GIVEN MOISTURE AND TIMING CONCERNS.
HIGH PRESSURE BUILDS IN LATER THU FOR DRY CONDITIONS THROUGH SAT.
HIGH TO SHIFT EAST OF AREA SAT NIGHT ALLOWING RETURN FLOW TO
DEVELOP. THIS WILL BRING A GOOD CHANCE OF SHOWERS AND ISOLD TSTMS
TO THE REGION SAT NIGHT INTO SUN.
COLDER AIR MOVES IN BEHIND STRONG COLD FRONT ON WED WITH
TEMPERATURES FALLING BACK TO NORMAL OR BELOW FOR REMAINDER OF
PERIOD. COOLEST TEMPERATURES EXPECTED FRI WITH COOL NORTHEAST
FLOW.
MAINTAINED SMALL CHANCE FOR LAKE EFFECT SHOWERS ON THU...THOUGH
WINDS MARGINAL. WILL LIKELY SEE LAKE CLOUDS AT TIMES OVER THE
NORTH THOUGH CAUSING HAVOC WITH LOW TEMP FORECASTS.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1238 AM CDT TUE SEP 10 2013
IFR/LIFR CIGS VSBYS WILL LINGER ACROSS THE NORTH AHEAD
OF WARM FRONT ACROSS NORTHERN WISCONSIN. MAINLY VFR CONDITIONS
WITH PATCHY MVFR VSBYS DUE TO HAZE ELSEWHERE. SOUTH SURFACE WINDS
AROUND 10 KNOTS WITH NEAR 40 KNOTS WINDS AT 2000 FEET WILL PRODUCE
LLWS CONDITIONS THIS MORNING.
SCATTERED CONVECTION ACROSS THE NORTH WILL COMBINE WITH THE
IFR/LIFR CONDITIONS THIS MORNING. SCATTERED CONVECTION WILL BE ON
THE INCREASE AGAIN LATER TODAY INTO TONIGHT AS A COLD FRONT DROPS
SOUTH OVER THE STATE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MG
LONG TERM......TE
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
931 AM MDT TUE SEP 10 2013
.UPDATE...A MOIST SOUTH-SOUTHWEST FLOW ALOFT WILL CONTINUE TO
PREVAIL THROUGH TONIGHT. IT APPEARS ON SATELLITE THAT A WAVE IS
MOVING ACROSS THE FOUR CORNERS AND IS TRIGGERING SHOWERS ACROSS
SOUTHEAST UTAH...SOUTHWEST COLORADO AND WESTERN NEW MEXICO. EVEN
THOUGH THE 06Z GFS HAS DRY CONDITIONS OVER NORTHEAST COLORADO THIS
AFTERNOON...EXPECT THE SHOWERS AND SCATTERED THUNDERSTORMS TO
FORM AS THIS WAVE SHIFT TO THE NORTHEAST. THE HRRR...RAP...AND
ECMWF ALL SUPPORT THIS. BEST CHANCE WILL BE OVER THE MOUNTAINS. IT
WILL WARM INTO THE 70S OVER FAR EASTERN COLORADO WHERE IT IS
PARTLY CLOUDY TO SUNNY. THIS WILL PRODUCE CAPES OF UP TO 500 J/KG.
THIS IS WHERE THE BEST CHANCE FOR STORMS WILL BE THIS AFTERNOON.
DECREASED TEMPERATURES A FEW DEGREES ALONG THE FRONT RANGE WHERE
CLOUD COVER WILL KEEP TEMPERATURES IN THE 60S TODAY. DID BUMP UP
POPS WEST OF INTERSTATE 25 WHERE SHOWERS AND A FEW THUNDERSTORMS
APPEAR LIKELY TODAY.
FOR TONIGHT...SOME DISAGREEMENT AMONG THE MODELS. ECMWF AND RAP
SHOW WIDESPREAD RAIN FROM GREELEY TO DIA AND WEST...WHILE THE NAM
AND GFS ARE DRY. FAVOR THE RAP AND ECMWF AT THIS TIME. RAISED
POPS FOR TONIGHT BUT WILL KEEP THEM IN 50-70 PERCENT RANGE UNTIL
IT BECOMES MORE CERTAIN THAT RAIN WILL OCCUR.
&&
.AVIATION...VERY LOW CEILINGS...LESS THAN 1000 FEET MAY LINGER
UNTIL 18Z ALONG THE FRONT RANGE. ELSEWHERE ACROSS THE DENVER
AREA...CEILINGS OF 1500 TO 3000 FEET WILL CONTINUE THROUGH 18Z.
CEILINGS WILL REMAIN 2500 TO 5000 THROUGH THE DAY TODAY. MAY BE
SOME SLIGHT VISIBILITY RESTRICTIONS UNDER THE STRONGER SHOWERS.
CEILINGS WILL LOWER AGAIN TONIGHT AND MAY DROP BELOW 1000 FEET
BETWEEN 06Z AND 18Z WEDNESDAY. IN ADDITION TO THE RAIN SHOWERS...A
FEW EMBEDDED THUNDERSTORMS WILL BE POSSIBLE BETWEEN 20Z AND 03Z
TODAY.
&&
.PREV DISCUSSION... /ISSUED 307 AM MDT TUE SEP 10 2013/
SHORT TERM...AN UPPER LEVEL LOW WILL REMAIN OVER THE SWRN US AS
DISTURBANCES EMBEDDED IN THE FLOW OF SUBTROPICAL MOISTURE MOVE
NNE ACROSS COLORADO. ONE WELL DEFINED FEATURE IS ALREADY MOVING
NORTHWARD OVER WRN CO EARLY THIS MORNING AND IS HELPING MAINTAIN
SHOWER ACTIVITY IN THE MTNS AND ALONG AND NR THE FOOTHILLS. AS
THIS FEATURE CONTINUES TO LIFT NORTH WOULD EXPECT SHOWER ACTIVITY
TO DECREASE BY MID MORNING IN MOST AREAS.
FOR THIS AFTN THERE IS A 2ND FEATURE CURRENTLY NOW ALONG THE ECTRL
AZ-WCNTRL NM BORDER WHICH IS MOVING NNE AS WELL. AS THIS FEATURE
LIFTS NNE INTO SWRN CO BY AFTN WOULD EXPECT SHOWERS AND TSTMS TO
INCREASE IN THE MTNS. EAST OF THE MTNS NOT SURE HOW THINGS ARE
GOING TO EVOLVE THIS AFTN. THE LATST HRRR DEVELOPS A WEAK CYCLONE
OVER SRN DOUGLAS COUNTY THIS AFTN WITH MAINLY ELY LOW LVL FLOW
OVER NERN CO. THE HRRR WARMS HIGHS INTO THE MID TO UPPER 70S OVER
THE PALMER DIVIDE WHILE FURTHER NORTH READINGS ARE ONLY IN THE
UPPER 60S TO NEAR 70 FM NORTH OF DENVER TO THE WY BORDER. IF THIS
ENDS UP BEING CORRECT THEN THE BEST CHC OF STRONGER STORMS WOULD
BE FM THE SRN FOOTHILLS ACROSS THE PALMER DIVIDE WHILE ACTIVITY
FURTHER NORTH WOULD NOT BE AS STG AND LESS WIDESPREAD. SO WILL
KEEP THE HIGHEST POPS FM DENVER SOUTH TO THE PALMER DIVIDE TOWARDS
LIMON. WITH PRECIPITABLE WATER VALUES RANGING FM 1.10 TO 1.20
INCHES THE STRONGER STORMS COULD EASILY PRODUCE UP TO 2 INCHES OF
RAIN IN LESS THAN AN HOUR. MEANWHILE OVER THE NERN PLAINS TEMPS
LOOK LIKE THEY WILL BE IN THE UPPER 70S TO LOWER 80S WITH TSTM
COVERAGE NOT AS GREAT.
FOR TONIGHT THE DISTURBANCE OVER SWRN CO WILL PROBABLY MOVE NNE
ACROSS THE MTNS AS SHOWN BY THE LATEST ECMWF. AS A RESULT THERE
WILL BE ADDITIONAL SHOWERS AND A FEW TSTMS IN THE MTNS WITH SOME OF
THIS ACTIVITY SPREADING ACROSS THE FOOTHILLS AND PORTIONS OF THE
URBAN CORRIDOR OVERNIGHT.
LONG TERM...MODELS CONTINUE TO INDICATE A DEEP...ANOMALOUSLY
MOIST SUBTROPICAL FLOW OVER NEW MEXICO...COLORADO AND THE WESTERN
GREAT PLAINS WEDNESDAY AND THURSDAY. MEAN LAYER PRECIPITABLE WATER
VALUES QUITE IMPRESSIVE FOR THIS TIME OF YEAR OVER EASTERN
COLORADO. VALUES MORE OFTEN OBSERVED IN JULY-EARLY AUGUST. FOR
INSTANCE...THE NAM...GFS...WRF AND SREF INDICATE PW VALUES UP
AROUND 1.25 INCHES ALONG THE FRONT RANGE FOOTHILLS WEDNESDAY
AFTERNOON. GFS STAYS JUST AS MOIST WEDNESDAY NIGHT AND
THURSDAY...WHILE THE NAM AND SREF INDICATE SOME DRYING ON
THURSDAY...BUT PW VALUES STILL ABOVE THE CLIMATOLOGICAL NORM. THIS
MOIST SOUTHERLY FLOW IS DRIVEN BY A NEARLY VERTICALLY STACKED
CYCLONE CENTERED NEAR LAS VEGAS ON WEDNESDAY. MODELS SHOW LITTLE
MOVEMENT IN THIS FEATURE THROUGH WEDNESDAY NIGHT. DIVERGENT FLOW
ALOFT EAST OF THE LOW OVER COLORADO IS PROGGED TO STRENGTHEN SOME
ON THURSDAY AS THE CYCLONE BEGINS ITS SLOW NORTHWARD MIGRATION.
STRONGEST UPWARD QUASI-GEOSTROPHIC VERTICAL VELOCITIES WEDNESDAY/
THURSDAY OVER EASTERN UTAH AND WESTERN COLORADO...WITH WEAK
RISING MOTIONS OVER EASTERN COLORADO. BY FRIDAY...MODELS SHOW THE
MEAN UPPER LOW OVER NRN UTAH/SERN IDAHO AND A SOUTHWESTERLY FLOW
OVER COLORADO. THIS WILL LOWER PW AND SPECIFIC HUMIDITY VALUES
ACROSS THE FORECAST AREA ON SATURDAY...PARTICULARLY IN THE HIGH
COUNTRY AS THE CLOSED UPPER CYCLONE OPENS UP INTO A TROUGH AND
SWINGS EAST OVER MONTANA AND WYOMING. BY SUNDAY ECMWF AND GFS
SHOW THE TROUGH PASSING OVER THE DAKOTAS ON SUNDAY...WITH THE
TAIL END OF THIS TROUGH AND WHAT APPEARS TO BE A COLD FRONT
BRUSHING NORTHEAST COLORADO. THIS WILL COOL TEMPERATURES BY AT
LEAST A FEW DEGS AND GIVE THE AREA ANOTHER CHANCE OF SHOWERS.
THEREFORE...WILL HANG ONTO THE HIGH POPS ON WEDNESDAY AND
THURSDAY...AND WITH THE WETBULB ZERO LOWERING LATE WEDNESDAY AND
THURSDAY...COULD SEE A SOME SNOW ACCUMULATION ON THE HIGHER PEAKS.
INSTABILITY WILL BE LIMITED DUE TO A HEAVY CLOUD COVER AND COOLER
TEMPERATURES. THIS WILL LIMIT THUNDERSTORM DEVELOPMENT AND THE
CHANCE OF HEAVY RAINFALL. SFC TEMPERATURES ARE LIKELY TO BE WELL
BELOW AVERAGE THROUGH AT LEAST THURSDAY NIGHT. LATEST NAM AND GFS
TEMPERATURE GUIDANCE FOR BOTH DAYS NOW LOOKS SLIGHTLY COOLER THAN
EARLIER GUIDANCE INDICATED. ECMWF TEMP GUIDANCE IS NOT AS COOL.
FCST HIGH TEMPERATURES BOTH DAYS IN THE 60S AT LOWER ELEVATIONS
AND 40S TO AROUND 60 IN THE HIGH COUNTRY. AT ANY RATE...IT`LL
DEFINITELY FEEL FALL-LIKE AFTER THE RECORD/NEAR RECORD HEAT OF THE
PAST COUPLE WEEKS. CONDITIONS SHOULD BEGIN TO WARM AND DRY OUT
FROM WEST TO EAST...SLOWLY AT FIRST...ON FRIDAY AND SATURDAY.
SHOULD SEE A MOVE AWAY FROM UPSLOPE TYPE STRATIFORM PRECIP TO
CONVECTIVE PRECIP/T-STORM ACTIVITY ON SATURDAY WITH THE LIFT
GENERATED BY THE TROUGH PASSING TO OUR NORTH AND WITH MORE SOLAR
HEATING. TEMPERATURES SHOULD BE NEAR AVERAGE ON SATURDAY. THEN A
DIP IN TEMPERATURE AND ANOTHER CHANCE OF SHOWERS ON SUNDAY WITH
THE PASSAGE OF THE COLD FRONT REFERRED TO ABOVE. BY MONDAY...
MODELS SHOW A RETURN TO DRIER AND WARMER CONDITIONS WITH WEST-
NORTHWESTERLY FLOW ALOFT AND DOWNSLOPE FLOW DOWN LOW.
AVIATION...A FEW SHOWERS MAY AFFECT THE AREA EARLY THIS MORNING
WITH BRIEF MVFR CONDITIONS POSSIBLE. WITH 5000-6000 FOOT CEILINGS
AROUND NOT SURE IF IFR CONDITIONS ARE GOING TO DVLP BUT AM NOT
CONFIDENT ENOUGH TO TOTALLY YANK THEM OUT AT THIS POINT.
FOR THIS AFTN SFC WINDS SHOULD BE MAINLY ELY. AS TALKED ABOUT ABV
BEST CHC OF STRONGER STORMS LOOKS TO BE FM DENVER SOUTH TO THE
PALMER DIVIDE WITH ACTIVITY DEVELOPING BY 20Z-21Z. DIA MAY END UP
BEING ON THE NRN FRINGE OF THE STRONGER ACTIVITY. HOWEVER IF A
STRONGER STORM WERE TO MOVE ACROSS THEN MVFR CONDITIONS COULD
BRIEFLY OCCUR.
BY TONIGHT INITIAL BATCH OF SHOWERS AND TSTMS WILL PROBABLY DIMINISH
BY 01Z HOWEVER SOME ADDITIONAL SHOWERS AND POSSIBLY A TSTM COULD
REDEVELOP AFTER MIDNIGHT AS A 2ND DISTURBANCE MOVES ACROSS. ONCE
AGAIN THERE COULD BE SOME POTENTIAL FOR STRATUS AND FOG BY 12Z WED
IF SKIES CLEAR LATE.
HYDROLOGY...SHOWERS AND THUNDERSTORMS WILL INCREASE BY EARLY
AFTERNOON IN THE MOUNTAINS...FOOTHILLS AND ALONG THE FRONT RANGE.
AT THIS TIME IT APPEARS THE STRONGEST STORMS WILL FOCUS FROM
DENVER SOUTHWARD ACROSS THE PALMER DIVIDE INTO THE SOUTHERN
FOOTHILLS. RAINFALL AMOUNTS OF 1 TO 2 INCHES WILL BE POSSIBLE WITH
THE STRONGER STORMS IN LESS THAN 45 MINUTES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....BAKER
AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1051 AM EDT TUE SEP 10 2013
.SYNOPSIS...
HIGH PRESSURE PUSHES EAST AS A WARM FRONT LIFTS NORTH THROUGH THE
NORTHEAST TODAY INTO TONIGHT. A COLD FRONT APPROACHES FROM THE
WEST WEDNESDAY INTO THURSDAY AND CROSSES THURSDAY NIGHT INTO
EARLY FRIDAY. CANADIAN HIGH PRESSURE BUILDS INTO THE REGION THIS
WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS AND THUNDERSTORMS CONTINUE TO APPROACH FROM THE
NORTH...AND SHOULD MOVE INTO ORANGE AND PUTNAM COUNTIES...AS WELL
AS INTERIOR PORTIONS OF SOUTHERN CT...WITHIN THE HOUR. LIGHTNING
ASSOCIATED WITH THESE STORMS HAVE DIMINISHED FAIRLY SIGNIFICANTLY
OVER THE LAST HOUR OR SO...AND WOULD EXPECT THAT TREND TO CONTINUE
AS THOSE STORMS TRACK TO THE SOUTHEAST.
BRIEF PERIOD OF LOCALLY HEAVY RAIN POSSIBLE...MAINLY FOR THE
INTERIOR ZONES AND FOR CT. LATEST HRRR HAS BEEN FAIRLY CONSISTENT
WITH ITS IMPACTING THOSE AREAS AND ITS CONTINUED WEAKENING INTO
THE EARLY AFTERNOON HOURS.
CONDITIONS EXPECTED TO DRY OUT BY THE AFTERNOON AS SUBSIDENCE
BUILDS IN ALOFT AND WARM FRONT MOVES NORTH.
TEMPS TODAY WELL ABOVE NORMAL...AND A GOOD 10 DEGREES WARMER THAN
YESTERDAY AS WE SEE THE WARM ADVECTION INCREASING 850MB TEMPS FROM
THE LOWER TEENS TO NEAR 20 DEGREES CELSIUS BY 00Z WED. DEPENDENT ON
HOW QUICKLY SKIES CLEAR...COULD SEE AN ADDITIONAL COUPLE DEGREES
ADDED TO FORECASTED HIGHS. FOR NOW WENT WITH BLEND OF MET/MAV WITH
EACH PROVIDING SIMILAR GUIDANCE.
THERE IS A MODERATE RIP CURRENT RISK AT THE OCEAN BEACHES TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
QUIET NIGHT IN STORE FOR THE TRI STATE WITH THE WARM FRONT QUICKLY
PUSHING TO THE NORTH AND THE ASSOCIATED LOW PRESSURE SYSTEM WELL TO
WEST. INCREASING SUBSIDENCE ALOFT SHOULD KEEP SKIES MAINLY
CLEAR...WITH INCREASING CLOUD COVERAGE BY EARLY TOMORROW MORNING. AN
INCREASING MOISTURE FIELD IN THE LOWER LEVELS COULD LEAD TO PATCHY
FOG DEVELOPMENT LATE IN THE NIGHT AS WELL...ESPECIALLY WITH WINDS
WEAKENING AFTER 06Z.
MAIN STORY FOR WEDNESDAY WILL BE THE WELL ABOVE NORMAL
TEMPERATURES...OVER 10 DEGREES ABOVE NORMAL AND SOME AREAS EVEN
NEARING RECORD HIGHS AS 850MB TEMPS SURGE INTO THE LOWER 20S. MUCH
BIGGER SPREAD IN TEMP GUIDANCE FOR HIGHS WED...AS THE MET PUSHES
TEMPS INTO THE LOWER 90S FOR MOST OF THE AREA. FEEL THIS MIGHT BE
A TAD TOO HIGH...SO SIDED WITH THE SLIGHTLY COOLER
SOLUTIONS...ESPECIALLY WITH INCREASING SKY COVERAGE AHEAD OF THE
APPROACHING COLD FRONT. HOWEVER...WITH DEW PTS ALSO PUSHING TO
AROUND 70...COULD STILL SEE A PERIOD WED AFTN WITH HEAT INDICES
REACHING INTO THE MID TO UPPER 90S OVER THE NYC METRO AREA AND
LOWER HUDSON RIVER VALLEY AND POSSIBLY EVEN REACHING THE CENTURY
MARK IN NYC. HOWEVER...CONFIDENCE IS NOT AS HIGH ON THIS BEING
ACCOMPLISHED...WITH THE BETTER CHANCE OF HEAT ADVISORY
CRITERIA...HI OF 95...BEING MET FOR A COUPLE OF HOURS. HIGH
CONFIDENCE OVERALL THOUGH OF A HOT AND HUMID DAY.
EXPECTING GENERALLY DRY CONDITIONS FOR THE FIRST PART OF WED...WITH
INCREASING POPS OVER AREAS WEST AND NORTH OF THE CITY BY LATE IN THE
DAY WITH INCREASING SURFACE BASED INSTABILITY AND AS THE UPPER LEVEL
TROUGH DEEPENS INTO THE NORTHEAST...PUSHING THROUGH MULTIPLE
SHORTWAVES. HOWEVER...THINKING THAT THE MAIN FORCING DURING THE DAY
WILL REMAIN NORTH OF THE AREA...WITH THE BETTER CHANCE FOR PRECIP
COMING WED NIGHT INTO THURSDAY. BECAUSE OF THE DEEP MOISTURE...ANY
THUNDERSTORM THAT DOES FORM COULD PRODUCE A QUICK HEAVY
RAINFALL...RESULTING IN MINOR FLOODING OF URBAN...AND POOR DRAINAGE
AREAS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
MODELS IN GOOD AGREEMENT WITH A TROUGH DIGGING FROM THE GREAT LAKES
TOWARDS THE NORTHEAST WED NIGHT THROUGH THU NIGHT.
ANY CONVECTION ACROSS WESTERN ZONES WEDNESDAY EVENING SHOULD
DIMINISH IN INTENSITY...WITH MAINLY ISOLATED SHRA/TSRA POTENTIAL
OVERNIGHT ACROSS FAR NW ZONES IN VICINITY OF A PRE-FRONTAL TROUGH.
VERY WARM AND HUMID CONDITIONS CONTINUE FOR THU...BUT MORE IN THE
WAY OF CLOUD COVER SHOULD KEEP TEMPS MAINLY IN THE LOWER TO MID 80S.
UPPER 80S POSSIBLE ACROSS NYC/NJ METRO IF ANY EXTENDED SUNSHINE.
MODELS HAVE TRENDED A BIT SLOWER WITH THE UPPER TROUGH APPROACH ON
THU. IF THIS TREND HOLD...THIS WOULD RETARD THE DEVELOPMENT OF MORE
WIDESPREAD SHOWER AND TSTM ACTIVITY ALONG/AHEAD OF A PRE-FRONTAL
TROUGH. FOR NOW HAVE TRENDED FORECAST IN THIS DIRECTION...WITH
SCATTERED TO NUMEROUS SHRA/TSRA DEVELOPING ACROSS WESTERN ZONES
ALONG/AHEAD OF THE PRE-FRONTAL TROUGH THU AFTERNOON. ISOLATED
DEVELOPMENT POSSIBLE ALONG SEA BREEZE BOUNDARY AND HIGHER ELEVATION
ELSEWHERE. WOULD EXPECTED THE ACTIVITY TO GRADUALLY TRANSLATE EAST
IN THE EVENING AS THE COLD FRONT ENTERS AND CROSSES THE REGION.
THE SLOWER APPROACH OF THE TROUGH WOULD KEEP STRONGER SHEAR TO THE
WEST OF THE REGION UNTIL LATE IN THE DAY. THIS WOULD ALSO MEAN
WEAKER MID-LEVEL LAPSE RATES...WITH MODERATE DE-STABILIZATION
DEPENDENT ON AMOUNT OF SUNSHINE. THE WEAKER SHEAR AND WIND PROFILE
WOULD ALSO LEAN AGAINST STORM ORGANIZATION. IF THIS TREND
HOLDS...A FEW PULSE STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE
ACROSS THE NYC/NJ METRO AND INTERIOR WITH ENOUGH SUNSHINE...BUT
PROBABILITY FOR ORGANIZED SEVERE WEATHER IS LOW. THIS WILL HAVE TO
WATCHED THOUGH AS A SLIGHTLY QUICKER TROUGH APPROACH WOULD INCREASE
THE SEVERE THREAT. SEE HYDROLOGY SECTION FOR FLOODING THREAT.
WITH APPROACHING SYNOPTIC SUPPORT THU NIGHT...AT LEAST SCATTERED
SHOWERS AND ISOLATED TSTM ACTIVITY SHOULD TRANSLATE INTO EASTERN
ZONES AHEAD OF THE COLD FRONTAL PASSAGE. ANY SEVERE THREAT SHOULD
DIMINISH IN THE EVENING WITH WEAKENING SURFACE INSTABILITY.
THEREAFTER...MODELS HAVE SIMILARLY TRENDED SLOWER WITH THE PASSAGE
OF THE TROUGH FRIDAY INTO SATURDAY...AS A SHORTWAVE COMING DOWN THE
BACKSIDE OF THE TROUGH DIGS IT INTO THE NORTHEAST...AND PERHAPS EVEN
DEVELOPS A CUTOFF LOW. THERE IS STILL SOME UNCERTAINTY ON THE
EVOLUTION OF THIS TROUGH...WHICH WILL DEPEND ON THE STRENGTH OF THE
BACKSIDE SHORTWAVE. A SLOWER AND MORE NEUTRALLY TILTED TROUGH
PASSAGE WOULD MEAN A SLOWER COLD FRONTAL PASSAGE...WITH SHOWER
ACTIVITY PRESUMABLY LINGERING INTO FRIDAY MORNING OR EVEN AFTERNOON.
CONFIDENCE IS AT LEAST INCREASING IN INSTABILITY CU AND ISOLATED
SHRA ACTIVITY FRI AFTERNOON AS THE UPPER TROUGH MOVING OVER THE
REGION.
OTHERWISE...A COOL FALL TYPE WEEKEND IS FORECAST WITH TEMPERATURES
AVERAGING 5 TO 10 DEGREES BELOW NORMAL SATURDAY THROUGH SUNDAY. DAY
TIME HIGH TEMPERATURES ON SATURDAY SHOULD REMAIN IN THE 60S WITH AT
LEAST PARTIAL SUNSHINE. DEPENDING ON TROUGH EVOLUTION...SATURDAY
COULD BE COOLER THAN FORECAST WITH MORE IN THE WAY OF INSTABILITY CU
AND EVEN A FEW SHOWERS N AND E.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
WARM FRONT LIFTS ACROSS THE AREA DURING THE FIRST HALF OF THE DAY.
MVFR CIGS TO PERSIST THROUGH 17-18Z...AND THEN SCATTER OUT. EASTERN
TERMINALS MAY HOLD ONTO MVFR CIGS UNTIL 19Z.
WINDS FROM S-SW PICK UP TO 10-15 KT SUSTAINED THRU LATE MORNING/EARLY
AFTERNOON WITH GUSTS AFTER 18Z UP TO 20 KT OR SO. OCCASIONAL GUSTS
PRIOR TO 18Z.
RAIN/SHOWERS EXPECTED TO REACH THE TERMINALS NORTH OF NYC. LOWER
CHANCE OF RAIN REACHING THE NYC TERMINAL. LOW POTENTIAL FOR ANY
THUNDER TO MAKE IT...ESPECIALLY TO THE CITY TERMINALS.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: TIMING OF END OF MVFR CIGS MAY BE OFF BY 1-2
HRS FROM FORECAST. GUSTS COULD BE A FEW KT HIGHER THAN FORECAST.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: TIMING OF END OF MVFR CIGS MAY BE OFF BY 1-2
HRS FROM FORECAST. GUSTS COULD BE A FEW KT HIGHER THAN FORECAST.
KLGA FCSTER COMMENTS: TIMING OF END OF MVFR CIGS MAY BE OFF BY 1-2
HRS FROM FORECAST. GUSTS COULD BE A FEW KT HIGHER THAN FORECAST.
KTEB FCSTER COMMENTS: TIMING OF END OF MVFR CIGS MAY BE OFF BY 1-2
HRS FROM FORECAST. GUSTS COULD BE MORE OCCASIONAL THAN FREQUENT
TODAY.
KHPN FCSTER COMMENTS: TIMING OF END OF MVFR CIGS MAY BE OFF BY
1-2 HRS FROM FORECAST.
KISP FCSTER COMMENTS: TIMING OF END OF MVFR CIGS MAY BE OFF BY 1-2
HRS FROM FORECAST. GUSTS COULD BE A FEW KT HIGHER THAN FORECAST.
OUTLOOK FOR 12Z WED THROUGH SAT...
.TUE NIGHT...PSBL MVFR/IFR VSBYS IN AREAS OF FOG THROUGH MORNING.
.WED-WED NIGHT...GENERALLY VFR WITH PSBL MVFR LATE IN THE DAY WITH
ISO-SCT PCPN AHEAD OF APPROACHING COLD FRONT. REDUCED CIGS/VIS
OVERNIGHT.
.THU...SCT SHOWERS/TSTMS WITH OCNL MVFR OR LOWER CONDS. COLD
FROPA LATE THU NIGHT.
.FRI...VFR. NW GUSTS 15-20 KTS PSBL IN THE AFTN.
.SAT...VFR. NW GUSTS 15-20 KTS PSBL IN THE AFTN.
&&
.MARINE...
OCCASIONAL GUSTS TO 25 KTS POSSIBLE ON THE OCEAN WATERS AND LONG
ISLAND BAYS TODAY WITH INCREASING ONSHORE FLOW. HOWEVER...
EXPECTING WINDS TO DIMINISH TONIGHT WITH THE FRONTAL PASSAGE...AND
WITH SUB-SCA CONDITIONS THEN REMAINING IN PLACE FOR ALL WATERS
THROUGH WED AS HIGH PRESSURE REMAINS ANCHORED OFFSHORE TO THE
EAST. SEAS INCREASE AS WELL WITH THE INCREASED WIND FLOW...BUT ARE
EXPECTED TO REMAIN BELOW 5 FT.
A STRENGTHENING S/SW FLOW LIKELY AHEAD OF AN APPROACHING COLD FRONT
WEDNESDAY NIGHT INTO THURSDAY. MARGINAL SCA GUSTS ARE POSSIBLE ON
THE OCEAN WATERS THU. THIS FLOW COULD HAVE SEAS BUILD TO AROUND 5 FT
LATE THU INTO THU NIGHT.
THE COLD FRONT CROSSES THE WATERS THURSDAY NIGHT THEN HIGH PRESSURE
BUILDS OVER THE WATERS FOR FRIDAY AND FRIDAY NIGHT. A PERIOD OF
MARGINAL SCA GUSTS POSSIBLE WITH STRONGEST CAA LATE FRI/FRI EVENING.
OFFSHORE FLOW SHOULD HAVE SEAS SUBSIDING BELOW SCA ON FRI.
AT THIS POINT IT APPEARS THAT SWELL CONTRIBUTIONS FROM TROPICAL
STORM GABRIELLE WILL BE SMALL...1 TO 2 FT LONG PERIOD ESE SWELLS
FOR FROM LATE WEEK INTO WEEKEND. REFER TO THE NATIONAL HURRICANE
CENTER FOR THE LATEST ON GABRIELLE.
SUB SCA CONDS EXPECTED FOR THE WEEKEND INTO EARLY NEXT WEEK AS HIGH
PRESSURE BUILDS INTO THE REGION.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH WEDNESDAY NIGHT.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EXPECTED THU
AFTERNOON THROUGH THURSDAY EVENING. MINOR URBAN AND POOR DRAINAGE
FLOODING IS THE PRIMARY THREAT...WITH A LOCALIZED FLASH FLOOD THREAT
WITH ANY TRAINING ACTIVITY.
ON AVERAGE WED NIGHT THRU THU NIGHT...A THIRD TO ONE INCH OF
RAINFALL IS POSSIBLE. THE HIGHEST AMOUNTS WILL LIKELY BE ACROSS
NORTHERN AND WESTERN ZONES.
&&
.CLIMATE...
WEDNESDAY IS FORECASTED TO BE THE WARMEST DAY THIS WEEK...WITH
HIGH TEMPERATURES PUSHING WELL ABOVE NORMAL. WHILE MOST OF THE
AREA IS FORECASTED TO HAVE HIGHS REMAIN A FEW DEGREES BELOW RECORD
VALUES...THESE TEMPS COMBINED WITH A VERY MOIST AIRMASS WILL
RESULT IN A HOT...UNSEASONABLE DAY.
LISTED BELOW ARE THE RECORD HIGHS AND THE FORECASTED HIGHS FOR
WEDNESDAY FOR EACH OF OUR 6 CLIMATE SITES.
SITE RECORD TEMPFORECASTED TEMP
------------------------------
BDR 90 (1983) 87
EWR 99 (1983) 93
ISP 88 (1989) 87
JFK 96 (1983) 88
LGA 96 (1983) 90
NYC 99 (1983)91
&&
.EQUIPMENT...
DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD EMERGENCY
BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS WEATHER
RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL WEATHER
SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES TO
ISOLATE AND RESOLVE THE TECHNICAL PROBLEM.
DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE
INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO
DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE
WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE
INTERFERENCE ISSUE HAS BEEN RESOLVED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SEARS/NV
NEAR TERM...SEARS/MPS
SHORT TERM...SEARS
LONG TERM...NV
AVIATION...BC/PICCA
MARINE...SEARS/NV
HYDROLOGY...SEARS/NV
CLIMATE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1035 AM EDT TUE SEP 10 2013
.SYNOPSIS...
HIGH PRESSURE PUSHES EAST AS A WARM FRONT LIFTS NORTH THROUGH THE
NORTHEAST TODAY INTO TONIGHT. A COLD FRONT APPROACHES FROM THE
WEST WEDNESDAY INTO THURSDAY AND CROSSES THURSDAY NIGHT INTO
EARLY FRIDAY. CANADIAN HIGH PRESSURE BUILDS INTO THE REGION THIS
WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS AND THUNDERSTORMS CONTINUE TO APPROACH FROM THE
NORTH...AND SHOULD MOVE INTO ORANGE AND PUTNAM COUNTIES...AS WELL
AS INTERIOR PORTIONS OF SOUTHERN CT...WITHIN THE HOUR. LIGHTNING
ASSOCIATED WITH THESE STORMS HAVE DIMINISHED FAIRLY SIGNIFICANTLY
OVER THE LAST HOUR OR SO...AND WOULD EXPECT THAT TREND TO CONTINUE
AS THOSE STORMS TRACK TO THE SOUTHEAST.
BRIEF PERIOD OF LOCALLY HEAVY RAIN POSSIBLE...MAINLY FOR THE
INTERIOR ZONES AND FOR CT. LATEST HRRR HAS BEEN FAIRLY CONSISTENT
WITH ITS IMPACTING THOSE AREAS AND ITS CONTINUED WEAKENING INTO
THE EARLY AFTERNOON HOURS.
CONDITIONS EXPECTED TO DRY OUT BY THE AFTERNOON AS SUBSIDENCE
BUILDS IN ALOFT AND WARM FRONT MOVES NORTH.
TEMPS TODAY WELL ABOVE NORMAL...AND A GOOD 10 DEGREES WARMER THAN
YESTERDAY AS WE SEE THE WARM ADVECTION INCREASING 850MB TEMPS FROM
THE LOWER TEENS TO NEAR 20 DEGREES CELSIUS BY 00Z WED. DEPENDENT ON
HOW QUICKLY SKIES CLEAR...COULD SEE AN ADDITIONAL COUPLE DEGREES
ADDED TO FORECASTED HIGHS. FOR NOW WENT WITH BLEND OF MET/MAV WITH
EACH PROVIDING SIMILAR GUIDANCE.
THERE IS A MODERATE RIP CURRENT RISK AT THE OCEAN BEACHES TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
QUIET NIGHT IN STORE FOR THE TRI STATE WITH THE WARM FRONT QUICKLY
PUSHING TO THE NORTH AND THE ASSOCIATED LOW PRESSURE SYSTEM WELL TO
WEST. INCREASING SUBSIDENCE ALOFT SHOULD KEEP SKIES MAINLY
CLEAR...WITH INCREASING CLOUD COVERAGE BY EARLY TOMORROW MORNING. AN
INCREASING MOISTURE FIELD IN THE LOWER LEVELS COULD LEAD TO PATCHY
FOG DEVELOPMENT LATE IN THE NIGHT AS WELL...ESPECIALLY WITH WINDS
WEAKENING AFTER 06Z.
MAIN STORY FOR WEDNESDAY WILL BE THE WELL ABOVE NORMAL
TEMPERATURES...OVER 10 DEGREES ABOVE NORMAL AND SOME AREAS EVEN
NEARING RECORD HIGHS AS 850MB TEMPS SURGE INTO THE LOWER 20S. MUCH
BIGGER SPREAD IN TEMP GUIDANCE FOR HIGHS WED...AS THE MET PUSHES
TEMPS INTO THE LOWER 90S FOR MOST OF THE AREA. FEEL THIS MIGHT BE
A TAD TOO HIGH...SO SIDED WITH THE SLIGHTLY COOLER
SOLUTIONS...ESPECIALLY WITH INCREASING SKY COVERAGE AHEAD OF THE
APPROACHING COLD FRONT. HOWEVER...WITH DEW PTS ALSO PUSHING TO
AROUND 70...COULD STILL SEE A PERIOD WED AFTN WITH HEAT INDICES
REACHING INTO THE MID TO UPPER 90S OVER THE NYC METRO AREA AND
LOWER HUDSON RIVER VALLEY AND POSSIBLY EVEN REACHING THE CENTURY
MARK IN NYC. HOWEVER...CONFIDENCE IS NOT AS HIGH ON THIS BEING
ACCOMPLISHED...WITH THE BETTER CHANCE OF HEAT ADVISORY
CRITERIA...HI OF 95...BEING MET FOR A COUPLE OF HOURS. HIGH
CONFIDENCE OVERALL THOUGH OF A HOT AND HUMID DAY.
EXPECTING GENERALLY DRY CONDITIONS FOR THE FIRST PART OF WED...WITH
INCREASING POPS OVER AREAS WEST AND NORTH OF THE CITY BY LATE IN THE
DAY WITH INCREASING SURFACE BASED INSTABILITY AND AS THE UPPER LEVEL
TROUGH DEEPENS INTO THE NORTHEAST...PUSHING THROUGH MULTIPLE
SHORTWAVES. HOWEVER...THINKING THAT THE MAIN FORCING DURING THE DAY
WILL REMAIN NORTH OF THE AREA...WITH THE BETTER CHANCE FOR PRECIP
COMING WED NIGHT INTO THURSDAY. BECAUSE OF THE DEEP MOISTURE...ANY
THUNDERSTORM THAT DOES FORM COULD PRODUCE A QUICK HEAVY
RAINFALL...RESULTING IN MINOR FLOODING OF URBAN...AND POOR DRAINAGE
AREAS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
MODELS IN GOOD AGREEMENT WITH A TROUGH DIGGING FROM THE GREAT LAKES
TOWARDS THE NORTHEAST WED NIGHT THROUGH THU NIGHT.
ANY CONVECTION ACROSS WESTERN ZONES WEDNESDAY EVENING SHOULD
DIMINISH IN INTENSITY...WITH MAINLY ISOLATED SHRA/TSRA POTENTIAL
OVERNIGHT ACROSS FAR NW ZONES IN VICINITY OF A PRE-FRONTAL TROUGH.
VERY WARM AND HUMID CONDITIONS CONTINUE FOR THU...BUT MORE IN THE
WAY OF CLOUD COVER SHOULD KEEP TEMPS MAINLY IN THE LOWER TO MID 80S.
UPPER 80S POSSIBLE ACROSS NYC/NJ METRO IF ANY EXTENDED SUNSHINE.
MODELS HAVE TRENDED A BIT SLOWER WITH THE UPPER TROUGH APPROACH ON
THU. IF THIS TREND HOLD...THIS WOULD RETARD THE DEVELOPMENT OF MORE
WIDESPREAD SHOWER AND TSTM ACTIVITY ALONG/AHEAD OF A PRE-FRONTAL
TROUGH. FOR NOW HAVE TRENDED FORECAST IN THIS DIRECTION...WITH
SCATTERED TO NUMEROUS SHRA/TSRA DEVELOPING ACROSS WESTERN ZONES
ALONG/AHEAD OF THE PRE-FRONTAL TROUGH THU AFTERNOON. ISOLATED
DEVELOPMENT POSSIBLE ALONG SEA BREEZE BOUNDARY AND HIGHER ELEVATION
ELSEWHERE. WOULD EXPECTED THE ACTIVITY TO GRADUALLY TRANSLATE EAST
IN THE EVENING AS THE COLD FRONT ENTERS AND CROSSES THE REGION.
THE SLOWER APPROACH OF THE TROUGH WOULD KEEP STRONGER SHEAR TO THE
WEST OF THE REGION UNTIL LATE IN THE DAY. THIS WOULD ALSO MEAN
WEAKER MID-LEVEL LAPSE RATES...WITH MODERATE DE-STABILIZATION
DEPENDENT ON AMOUNT OF SUNSHINE. THE WEAKER SHEAR AND WIND PROFILE
WOULD ALSO LEAN AGAINST STORM ORGANIZATION. IF THIS TREND
HOLDS...A FEW PULSE STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE
ACROSS THE NYC/NJ METRO AND INTERIOR WITH ENOUGH SUNSHINE...BUT
PROBABILITY FOR ORGANIZED SEVERE WEATHER IS LOW. THIS WILL HAVE TO
WATCHED THOUGH AS A SLIGHTLY QUICKER TROUGH APPROACH WOULD INCREASE
THE SEVERE THREAT. SEE HYDROLOGY SECTION FOR FLOODING THREAT.
WITH APPROACHING SYNOPTIC SUPPORT THU NIGHT...AT LEAST SCATTERED
SHOWERS AND ISOLATED TSTM ACTIVITY SHOULD TRANSLATE INTO EASTERN
ZONES AHEAD OF THE COLD FRONTAL PASSAGE. ANY SEVERE THREAT SHOULD
DIMINISH IN THE EVENING WITH WEAKENING SURFACE INSTABILITY.
THEREAFTER...MODELS HAVE SIMILARLY TRENDED SLOWER WITH THE PASSAGE
OF THE TROUGH FRIDAY INTO SATURDAY...AS A SHORTWAVE COMING DOWN THE
BACKSIDE OF THE TROUGH DIGS IT INTO THE NORTHEAST...AND PERHAPS EVEN
DEVELOPS A CUTOFF LOW. THERE IS STILL SOME UNCERTAINTY ON THE
EVOLUTION OF THIS TROUGH...WHICH WILL DEPEND ON THE STRENGTH OF THE
BACKSIDE SHORTWAVE. A SLOWER AND MORE NEUTRALLY TILTED TROUGH
PASSAGE WOULD MEAN A SLOWER COLD FRONTAL PASSAGE...WITH SHOWER
ACTIVITY PRESUMABLY LINGERING INTO FRIDAY MORNING OR EVEN AFTERNOON.
CONFIDENCE IS AT LEAST INCREASING IN INSTABILITY CU AND ISOLATED
SHRA ACTIVITY FRI AFTERNOON AS THE UPPER TROUGH MOVING OVER THE
REGION.
OTHERWISE...A COOL FALL TYPE WEEKEND IS FORECAST WITH TEMPERATURES
AVERAGING 5 TO 10 DEGREES BELOW NORMAL SATURDAY THROUGH SUNDAY. DAY
TIME HIGH TEMPERATURES ON SATURDAY SHOULD REMAIN IN THE 60S WITH AT
LEAST PARTIAL SUNSHINE. DEPENDING ON TROUGH EVOLUTION...SATURDAY
COULD BE COOLER THAN FORECAST WITH MORE IN THE WAY OF INSTABILITY CU
AND EVEN A FEW SHOWERS N AND E.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
WARM FRONT LIFTS ACROSS THE AREA DURING THE FIRST HALF OF THE DAY.
MVFR CIGS TO PERSIST THROUGH 15-16Z...AND THEN SCATTER OUT. LOW
POTENTIAL FOR KEWR/KTEB/KHPN/KSWF TO SEE BRIEF IFR CIGS OVER NEXT
COUPLE OF HOURS. EASTERN TERMINALS MAY HOLD ONTO MVFR CIGS UNTIL
17-18Z.
WINDS FROM S-SW PICK UP TO 10-15 KT SUSTAINED THRU LATE MORNING /
EARLY AFTERNOON WITH GUSTS UP TO 20 KT OR SO. OCCASIONAL GUSTS
PRIOR TO 15-16Z.
SOME POTENTIAL FOR SHOWERS FROM UPSTATE COMPLEX TO REACH NW
TERMINALS THIS AFTERNOON. LOW POTENTIAL FOR ANY THUNDER TO MAKE
IT...ESPECIALLY TO THE CITY TERMINALS. THEREFORE...NO MENTION IN
TAFS.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: TIMING OF END OF MVFR CIGS MAY BE OFF BY 1-2
HRS FROM FORECAST. GUSTS COULD BE A FEW KT HIGHER THAN FORECAST.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: TIMING OF END OF MVFR CIGS MAY BE OFF BY 1-2
HRS FROM FORECAST. GUSTS COULD BE A FEW KT HIGHER THAN FORECAST.
KLGA FCSTER COMMENTS: TIMING OF END OF MVFR CIGS MAY BE OFF BY 1-2
HRS FROM FORECAST. GUSTS COULD BE A FEW KT HIGHER THAN FORECAST.
KTEB FCSTER COMMENTS: TIMING OF END OF MVFR CIGS MAY BE OFF BY 1-2
HRS FROM FORECAST. GUSTS COULD BE MORE OCCASIONAL THAN FREQUENT
TODAY.
KHPN FCSTER COMMENTS: TIMING OF END OF MVFR CIGS MAY BE OFF BY
1-2 HRS FROM FORECAST.
KISP FCSTER COMMENTS: TIMING OF END OF MVFR CIGS MAY BE OFF BY 1-2
HRS FROM FORECAST. GUSTS COULD BE A FEW KT HIGHER THAN FORECAST.
OUTLOOK FOR 12Z WED THROUGH SAT...
.TUE NIGHT...PSBL MVFR/IFR VSBYS IN AREAS OF FOG THROUGH MORNING.
.WED-WED NIGHT...GENERALLY VFR WITH PSBL MVFR LATE IN THE DAY WITH
ISO-SCT PCPN AHEAD OF APPROACHING COLD FRONT. REDUCED CIGS/VIS
OVERNIGHT.
.THU...SCT SHOWERS/TSTMS WITH OCNL MVFR OR LOWER CONDS. COLD
FROPA LATE THU NIGHT.
.FRI...VFR. NW GUSTS 15-20 KTS PSBL IN THE AFTN.
.SAT...VFR. NW GUSTS 15-20 KTS PSBL IN THE AFTN.
&&
.MARINE...
OCCASIONAL GUSTS TO 25 KTS POSSIBLE ON THE OCEAN WATERS AND LONG
ISLAND BAYS TODAY WITH INCREASING ONSHORE FLOW. HOWEVER...
EXPECTING WINDS TO DIMINISH TONIGHT WITH THE FRONTAL PASSAGE...AND
WITH SUB-SCA CONDITIONS THEN REMAINING IN PLACE FOR ALL WATERS
THROUGH WED AS HIGH PRESSURE REMAINS ANCHORED OFFSHORE TO THE
EAST. SEAS INCREASE AS WELL WITH THE INCREASED WIND FLOW...BUT ARE
EXPECTED TO REMAIN BELOW 5 FT.
A STRENGTHENING S/SW FLOW LIKELY AHEAD OF AN APPROACHING COLD FRONT
WEDNESDAY NIGHT INTO THURSDAY. MARGINAL SCA GUSTS ARE POSSIBLE ON
THE OCEAN WATERS THU. THIS FLOW COULD HAVE SEAS BUILD TO AROUND 5 FT
LATE THU INTO THU NIGHT.
THE COLD FRONT CROSSES THE WATERS THURSDAY NIGHT THEN HIGH PRESSURE
BUILDS OVER THE WATERS FOR FRIDAY AND FRIDAY NIGHT. A PERIOD OF
MARGINAL SCA GUSTS POSSIBLE WITH STRONGEST CAA LATE FRI/FRI EVENING.
OFFSHORE FLOW SHOULD HAVE SEAS SUBSIDING BELOW SCA ON FRI.
AT THIS POINT IT APPEARS THAT SWELL CONTRIBUTIONS FROM TROPICAL
STORM GABRIELLE WILL BE SMALL...1 TO 2 FT LONG PERIOD ESE SWELLS
FOR FROM LATE WEEK INTO WEEKEND. REFER TO THE NATIONAL HURRICANE
CENTER FOR THE LATEST ON GABRIELLE.
SUB SCA CONDS EXPECTED FOR THE WEEKEND INTO EARLY NEXT WEEK AS HIGH
PRESSURE BUILDS INTO THE REGION.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH WEDNESDAY NIGHT.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EXPECTED THU
AFTERNOON THROUGH THURSDAY EVENING. MINOR URBAN AND POOR DRAINAGE
FLOODING IS THE PRIMARY THREAT...WITH A LOCALIZED FLASH FLOOD THREAT
WITH ANY TRAINING ACTIVITY.
ON AVERAGE WED NIGHT THRU THU NIGHT...A THIRD TO ONE INCH OF
RAINFALL IS POSSIBLE. THE HIGHEST AMOUNTS WILL LIKELY BE ACROSS
NORTHERN AND WESTERN ZONES.
&&
.CLIMATE...
WEDNESDAY IS FORECASTED TO BE THE WARMEST DAY THIS WEEK...WITH
HIGH TEMPERATURES PUSHING WELL ABOVE NORMAL. WHILE MOST OF THE
AREA IS FORECASTED TO HAVE HIGHS REMAIN A FEW DEGREES BELOW RECORD
VALUES...THESE TEMPS COMBINED WITH A VERY MOIST AIRMASS WILL
RESULT IN A HOT...UNSEASONABLE DAY.
LISTED BELOW ARE THE RECORD HIGHS AND THE FORECASTED HIGHS FOR
WEDNESDAY FOR EACH OF OUR 6 CLIMATE SITES.
SITE RECORD TEMPFORECASTED TEMP
------------------------------
BDR 90 (1983) 87
EWR 99 (1983) 93
ISP 88 (1989) 87
JFK 96 (1983) 88
LGA 96 (1983) 90
NYC 99 (1983)91
&&
.EQUIPMENT...
DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD EMERGENCY
BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS WEATHER
RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL WEATHER
SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES TO
ISOLATE AND RESOLVE THE TECHNICAL PROBLEM.
DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE
INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO
DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE
WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE
INTERFERENCE ISSUE HAS BEEN RESOLVED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SEARS/NV
NEAR TERM...SEARS/MPS
SHORT TERM...SEARS
LONG TERM...NV
AVIATION...PICCA
MARINE...SEARS/NV
HYDROLOGY...SEARS/NV
CLIMATE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1032 AM EDT TUE SEP 10 2013
.SYNOPSIS...
AN APPROACHING WARM FRONT WILL BRING CLOUDS ACROSS THE REGION
ALONG WITH THE CHANCE OF A FEW SHOWERS THIS MORNING. THE FRONT
WILL LIFT THROUGH THE REGION LATE TODAY AND TONIGHT...BRINGING
VERY WARM AND MORE HUMID WEATHER FOR MID WEEK. A COLD FRONT WILL
LIKELY BRING SHOWERS AND THUNDERSTORMS WITH GUSTY WINDS AND HEAVY
RAIN THURSDAY AND THURSDAY NIGHT. HIGH PRESSURE RETURNS FOR NEXT
WEEKEND WITH DRY AND MUCH COOLER WEATHER.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1030 AM UPDATE...
CONVECTIVE COMPLEX ENTERING WESTERN NEW ENGLAND CONTINUES TO SHOW
SLOW WEAKENING WITH TIME AS IT OUT RUNS BETTER INSTABILITY ALOFT
WESTWARD ACROSS NY STATE AND THE GREAT LAKES. HOWEVER THESE STORMS
WILL CONTAIN BRIEF HEAVY RAIN AND LIGHTNING. AS FOR WINDS...SOUTHERN
NEW ENGLAND REMAINS ON THE COOL SIDE OF THE BOUNDARY SO STABLE LOW
LEVELS SHOULD PRECLUDE STRONGER WINDS ALOFT FROM MIXING DOWNWARD
TO THE SURFACE.
ONLY THE HRRR IS CAPTURING THE EVOLUTION OF THIS CONVECTIVE
COMPLEX. THUS THIS FORECAST UPDATE IS HEAVILY BASED ON THE TIMING
FROM THE PAST FEW RUNS OF THE HRRR. SHOWERS AND TSTMS WILL RACE
ACROSS THE ENTIRE REGION AND MAKE IT ALL THE WAY TO THE CAPE
/ALBEIT IN A WEAKEN STATE/ AROUND 19Z AND THEN OFFSHORE 21Z- 23Z.
COULD SEE SOME LATE DAY SUNSHINE ACROSS WESTERN AREAS BUT TRUE
WARM SECTOR WILL NOT OVERSPREAD THE REGION UNTIL TONIGHT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
TONIGHT...
WARM SECTOR WORKS IN FULL FORCE TONIGHT WITH A WARM...SULTRY NIGHT
IN PLACE ACROSS THE REGION. EXPECT PATCHY FOG TO DEVELOP...SOME OF
WHICH WILL BE LOCALLY DENSE ALONG THE COAST WITH HIGH DEWPTS IN
PLACE. H5 RIDGING BUILDS ACROSS THOUGH TENDS TO FLATTEN
OVERNIGHT. NOT EXPECTING ANY PRECIP THANKS TO H5 RIDGING THAT
BUILDS ACROSS...THOUGH TENDS TO FLATTEN OVERNIGHT. LOWS WILL BE IN
THE MID 60S TO LOWER 70S...MILDEST ALONG THE COAST AND URBAN
CENTERS.
WEDNESDAY...
HARD TO IGNORE SHORT RANGE MODELS WITH RATHER STRONG CONVECTIVE
SIGNALS WHICH HAVE CARRIED ON FOR SEVERAL MODEL RUNS NOW. NOTING A
WEAK TROUGH LINGERING ACROSS THE REGION AT THE SURFACE...BUT BULK
OF PRECIP WILL REMAIN WELL NW OF THE REGION WITH THE COLD FRONT
WORKING OUT OF SOUTHERN CANADA. LOOKS LIKE THIS TROUGHING WILL BE
THE FOCUS OF ANY SHOWERS/TSTMS THAT DEVELOP DURING THE
AFTERNOON/EVENING HOURS. GOOD LAPSE RATES TO MOVE IN ACROSS THE
REGION...ON ORDER OF 6.5 TO 7C/KM WITH MARGINAL SW SHEAR AT 20-25
KT. BETTER JET DYNAMICS REMAIN ACROSS CENTRAL AND NORTHERN NEW
ENGLAND. BIG ISSUE WITH ALL THIS WILL BE WHETHER LOW CLOUDS/FOG
BREAK TO ALLOW FOR MIXING AND BREAKING THE CAPPING IN PLACE WITH
RATHER HIGH CIN IN PLACE.
FEEL THERE WILL BE A CHANCE FOR SHOWERS/TSTMS MAINLY FROM NEAR
KLWM-KBED-KHFD N AND W DURING THE AFTERNOON. DID NOT USE ENHANCED
WORDING YET...BUT COULD SEE SOME HEAVY RAINFALL WITH SOME OF THESE
STORMS AS PWATS INCREASE TO 1.5 TO 1.75 INCHES. THIS WILL NEED TO
BE WATCHED CAREFULLY THOUGH...AS SOME OF THE INSTABILITY
PARAMETERS ARE IMPRESSIVE INCLUDING CAPES UP TO 2400 J/KG AND
TOTAL TOTALS IN THE LOWER-MID 50S AS SEEN ON THE 00Z GFS...NOT TOO
FAR FROM THAT ON THE 12Z ECWMF.
WILL BE A VERY WARM AND HUMID DAY WITH DEWPTS IN THE LOWER 70S.
HIGHS WILL BE IN THE LOWER 90S WELL INLAND...HOLDING IN THE UPPER
70S- MID 80S ALONG THE S COAST...CAPE COD AND THE ISLANDS. ONE
MORE ASPECT...IT IS MARGINAL AT THIS POINT BUT MAY NEED TO
CONSIDER HEAT ADVISORY IF TEMPS GO HIGHER THAN LOWER 90S. NO
RECORDS APPEAR TO BE THREATENED AS THE 9/11 RECORD HIGHS APPEAR TO
BE THE HIGHEST FOR THE MONTH OF SEPTEMBER. PLEASE SEE LIST IN THE
CLIMATE SECTION.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
BIG PICTURE...
SUBTROPICAL HIGH BUILDS THROUGH THE WESTERN USA WHILE A TROUGH
DIGS OVER THE NORTHEAST. THE WESTERN HIGH BREAKS DOWN BY THE
WEEKEND. THE ECMWF AND GFS BOTH TRY TO FORM A CUTOFF LOW OVER NEW
ENGLAND DURING THE WEEKEND...BUT THEY JUST AS QUICKLY MOVE THE LOW
OFF THROUGH THE MARITIMES ON SUNDAY. SHORTWAVE FROM NORTHERN
CANADA SWEEPS SOUTH AND REACHES NEW ENGLAND EARLY NEXT WEEK. THIS
WILL MAINTAIN THE EASTERN TROUGH.
THE GFS AND ECMWF MASS FIELDS ARE SIMILAR THROUGH SUNDAY...WITH
EMERGING DIFFERENCES WITH THE CANADIAN SHORTWAVE ON MONDAY. THE
FORECAST USES A BLEND OF LONG RANGE GUIDANCE.
THE DAILIES...
WEDNESDAY NIGHT...GFS AND GGEM SHOW A GOOD UPPER DIVERGENCE/LOW
LEVEL CONVERGENCE COUPLET OVER CT-RI-SE MASS AT 00Z. THE REMAINING
MODELS ARE LESS CLEAR ON THIS POINT. FAVORABLE MID LEVEL LAPSE
RATES OF AROUND 7C/KM LINGER THROUGH THE FIRST PART OF THE NIGHT.
TOTALS IN THE LOWER 50S. SURFACE BASED CAPES 1000-2000J/KG DURING
THE FIRST PART OF THE NIGHT...MAINLY SRN NH AND NORTHWEST MASS.
PRECIPITABLE WATER VALUES BETWEEN 1.5 AND 2.0.
EXPECT A LINGERING CHANCE OF TSTMS ESPECIALLY ACROSS SOUTHERN NH AND
WESTERN/CENTRAL MASS. COULD BE SOME HEAVY DOWNPOURS WITH ANY TSTMS.
A MILD MUGGY NIGHT WITH MIN TEMPS AROUND 70 AS PER MOS.
THURSDAY... TROUGH DIGGING OVER THE GREAT LAKES PUSHES A COLD FRONT
INTO THE WARM HUMID AIRMASS OVER NEW ENGLAND. SEVERAL FEATURES OF
INTEREST INCLUDING FAVORABLE INSTABILITY AND AN APPROACHING RIGHT
ENTRANCE REGION OF THE UPPER JET. HIGH PW VALUES LINGER. WINDS
ALOFT BECOME MORE FAVORABLE WITH 20-30 KNOTS AT 850 MB AND 40 KNOTS
AT 500 MB. THIS POINTS TO POTENTIAL FOR STRONG CONVECTION WITH THE
BEST CHANCE IN SOUTHWEST NH AND NORTHWEST MASS. HEAVY DOWNPOURS AND
LOCAL POOR DRAINAGE FLOODING ALSO LOOK POSSIBLE. SUFFICIENT FACTORS
EXIST TO SUPPORT LIKELY POPS FOR SHOWERS/TSTMS.
HIGH TEMPS WILL DEPEND ON THE AMOUNT OF SUNSHINE THAT WE GET THAT
DAY...SIGNIFICANT CLOUD DEBRIS FROM UPSTREAM CONVECTION WOULD HOLD
DOWN THE HEATING. HIGH DEWPOINTS SHOULD START THE MORNING AROUND 70.
MIXING TO 850 MB WOULD SUPPORT MAX TEMPS IN THE 80S. SUCH MIXING
WOULD ALSO BRING SOUTHWEST WINDS OF 20-25 KNOTS TO THE SURFACE.
CONSENSUS ON FRONTAL PASSAGE BRINGS IT THROUGH NEW ENGLAND DURING
THURSDAY NIGHT. EXPECT THE CHANCE OF SHOWERS TO DIMINISH AFTER FROPA
WITH WINDS TURNING NORTHWEST.
FRIDAY... QUESTION MARK FOR FRIDAY WILL BE THE AMOUNT OF CLOUDS THAT
LINGER OVER THE REGION. THE APPROACHING TROUGH AND ITS ASSOCIATED
JET MAY BE ABLE TO GENERATE A WAVE ALONG THE DEPARTING COLD FRONT.
THIS WOULD KEEP CLOUDS/SHOWERS OVER AT LEAST A PART OF OUR AREA...RI
AND EASTERN MASS WOULD BE MOST AT RISK. MEANWHILE THE APPROACHING
COLD POOL ALOFT WOULD SERVE TO DESTABILIZE THE AIRMASS AND PROMOTE
DIURNAL CLOUDS AND POSSIBLY A SHOWER. SO IF ONE DOESN/T GET US
PERHAPS THE OTHER WILL? THE FORECAST SHOWS A MIX OF CLOUDS AND SUN
WITH DEPARTING SHOWERS OFF THE EAST COAST AND ARRIVING SHOWERS OVER
THE NORTHERN INTERIOR.
SATURDAY-SUNDAY... HIGH PRESSURE BUILDS IN AT THE SURFACE WHILE THE
UPPER LOW TWIRLS OVERHEAD. EXPECT SOME CLOUDS AND WIDELY SCATTERED
SHOWERS ESPECIALLY ON SATURDAY AND ESPECIALLY OVER SOUTHERN
NH/NORTHERN MASS. TEMPS AT 850 MB WILL BE 2-4C SATURDAY AND 6-9C ON
SUNDAY. SO MAX TEMPS SATURDAY SHOULD BE IN THE 60S AND WITH WARMER
TEMPS ON SUNDAY.
MONDAY... COLD FRONT DRIVES SOUTH FROM CANADA. THE ECMWF SHOWS
CLOUDS AND SHOWERS...THE GFS HAS A PERIOD OF CLOUDS BUT DIMINISHES
THE SHOWERS AS THE FRONT MOVES INTO NEW ENGLAND. NOT MUCH CONFIDENCE
IN THE OCCURRENCE OF SHOWERS SO WE HELD AT SLIGHT CHANCE.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW /THROUGH WEDNESDAY/...MODERATE CONFIDENCE THIS MORNING...
THEN LOWER CONFIDENCE THIS AFTERNOON THROUGH WEDNESDAY.
1030 AM UPDATE...
TSTMS OVER WESTERN NEW ENGLAND WILL CONTINUE TO SLOWLY WEAKEN
BUT SHOULD HOLD TOGETHER AND MOVE ACROSS THE ENTIRE REGION
REACHING BOSTON AROUND 16Z AND PROVIDENCE 17Z-18Z THEN TO CAPE COD
AND THE ISLANDS 19Z-21Z AND FINALLY OFFSHORE BY 23Z. STRONG WINDS
ALOFT WILL LIKELY NOT REACH THE SURFACE GIVEN COOL/STABLE LOW
LEVELS. MAIN THREATS HEAVY RAIN AND LIGHTNING.
--------------------------------------------------------------
TODAY...MAINLY VFR. AREAS OF MVFR CIGS THIS MORNING WITH SCT
SHOWERS/TSTMS THROUGH 15Z ACROSS S NH/N CENTRAL AND W MA INTO N
CENTRAL CT. TIMING ON EROSION OF MVFR CIGS TOUGH AS HUMIDITY
INCREASE WITH WARM FRONTAL PASSAGE. EXPECT ANY PRECIP THREAT TO
DIMINISH DURING THE AFTERNOON.
TONIGHT...EXPECT LINGERING MVFR/VFR CIGS. PATCHY FOG DEVELOPING
WITH MVFR VSBYS. IFR CIGS/VSBYS MAY DEVELOP AROUND OR AFTER
MIDNIGHT...ESPECIALLY OVER RI/E MA...THOUGH LOW CONFIDENCE ON
THIS ASPECT.
WEDNESDAY...MODERATE CONFIDENCE. MAINLY VFR...BUT AREAS OF EARLY
MORNING MVFR/IFR STRATUS/FOG. LOW PROB OF SCT TSTMS DURING THE
AFTERNOON/EVENING NW AREAS.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF THIS MORNING...THEN
INCREASING UNCERTAINTY THIS AFTN AND EVENING. ANY MVFR CLOUDS/CIGS
MAY BE STUBBORN TO BURN OFF THIS AFTN...THEN MAY REFORM TUE NIGHT
INTO IFR CONDITIONS.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF THROUGH TUE MORNING THEN
INCREASING UNCERTAINTY TUE AFTN AND NIGHT.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
WEDNESDAY NIGHT...LINGERING SHOWERS/TSTMS ESPECIALLY OVER SOUTHERN
NH AND NORTHWEST MASS. BRIEF LOW CIGS AND VSBYS WITH ANY STORMS.
THURSDAY...PATCHES OF FOG AND LOW CLOUDS THURSDAY MORNING WITH
RESULTING IFR CONDITIONS. AS THE CLOUDS BURN OFF...INCREASING
SOUTHWEST WINDS WITH GUSTS 20-25 KNOTS POSSIBLE IN THE AFTERNOON.
ALSO IN THE AFTERNOON/EVENING WILL BE A CHANCE OF SHOWERS/TSTMS WITH
BRIEF LOWERING OF CIGS/VSBYS AS WELL AS STRONG WIND GUSTS AND HEAVY
DOWNPOURS. WINDS SHIFT TO NORTHWEST AND DIMINISH LATE THURSDAY
NIGHT. MODERATE CONFIDENCE.
FRIDAY...POTENTIAL FOR LINGERING CLOUDS IN THE MORNING ESPECIALLY
CAPE COD AND ISLANDS. GENERALLY VFR WITH NORTHWEST WINDS GUSTING TO
20 KNOTS. MODERATE CONFIDENCE.
SATURDAY...VFR. MODERATE TO HIGH CONFIDENCE.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH TUESDAY NIGHT/...HIGH CONFIDENCE.
TODAY...LIGHT S-SW WINDS WILL PICK UP AS WARM FRONT APPROACHES
THIS AFTERNOON. BIG QUESTION WILL BE HOW MUCH WIND MIXES DOWN
THIS AFTERNOON AS WARM AIR SURGES IN. WHILE IT IS MARGINAL...
DECIDED TO RAISE SMALL CRAFTS FOR THE OUTER WATERS WITH GUSTS TO
25 KT AND SEAS UP TO 5 FT.
TONIGHT...EXPECT SW WINDS TO CONTINUE THOUGH DIMINISHING DURING
THE OVERNIGHT HOURS. STILL EXPECT GUSTS UP TO 25 KT AND SEAS
AROUND 5 FT ON OUTER WATERS...BUT SHOULD SUBSIDE BY WED MORNING.
WITH HUMID AIRMASS IN PLACE...EXPECT PATCHY FOG TO DEVELOP WITH
LOCALLY DENSE POCKETS.
WEDNESDAY...SW WINDS CONTINUE THOUGH NOT QUITE AS GUSTY. MAY START
TO PICK UP AS COLD FRONT BEGINS TO APPROACH. SEAS MAY REMAIN
AROUND 5 FT ON THE SOUTHERN OUTER WATERS WITH CONTINUED SW FETCH.
VSBYS WILL LIKELY BE REDUCED DUE TO AREAS OF FOG...SOME LOCALLY
DENSE THROUGH MIDDAY.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
WEDNESDAY NIGHT...SEAS REMAIN AROUND 5 FEET ON THE OUTER WATERS.
SOUTHWEST WINDS AROUND 15 KNOTS. A SMALL CRAFT ADVISORY MAY BE
NEEDED FOR THE OUTER WATERS.
THURSDAY...SOUTHWEST WINDS GUSTING TO 25 KNOTS. SEAS ON THE EXPOSED
WATERS WILL BE 5-6 FEET. A SMALL CRAFT ADVISORY WILL BE LIKELY FOR
THURSDAY. SHOWERS AND TSTMS DEVELOP AHEAD OF AN APPROACHING COLD
FRONT. THE FRONT MOVES THROUGH DURING THURSDAY NIGHT...WINDS THEN
BECOME NORTHWEST.
FRIDAY... NORTHWEST WINDS GUSTING TO 20 KNOTS. SEAS START NEAR 5
FEET AND SUBSIDE THROUGH THE DAY.
SATURDAY...NORTH WINDS WITH GUSTS 20 TO 25 KNOTS ESPECIALLY EAST OF
CAPE COD. SEA RE-BUILD TO 5-6 FEET.
&&
.CLIMATE...
RECORD MAX TEMPS FOR WED 9/11...
BOS 99/1983
PVD 100/1983
BDL 99/1983
ORH 91/1983
LATEST MAX TEMP OF 90 OR HIGHER...
BOS OCTOBER 12 1954
PVD SEPTEMBER 23 1970
BDL OCTOBER 17 1908
ORH SEPTEMBER 26 1930
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 6 PM EDT
WEDNESDAY FOR ANZ250-254>256.
&&
$$
SYNOPSIS...WTB/EVT
NEAR TERM...WTB/NOCERA/EVT
SHORT TERM...EVT
LONG TERM...WTB
AVIATION...WTB/NOCERA/EVT
MARINE...WTB/EVT
CLIMATE...
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
929 AM EDT TUE SEP 10 2013
...MODERATE RISK FOR RIP CURRENTS ALONG THE BEACHES OF NORTH
COASTAL GEORGIA THROUGH THIS EVENING...
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND ACROSS THE AREA THROUGH THE MIDDLE OF
THE WEEK BEFORE A BACKDOOR COLD FRONT DROPS ACROSS THE AREA LATE
FRIDAY AND FRIDAY NIGHT. COOLER HIGH PRESSURE WILL THEN BUILD INTO
THE REGION FROM THE NORTH INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A WELL DEFINED LAND BREEZE COUPLED WITH A NOTICEABLE WIND SURGE
WORKING DOWN THE SOUTH CAROLINA AND GEORGIA COASTS HAS PROMOTED
STRONG SURFACE MOISTURE FLUX CONVERGENCE IN EXCESS OF 20 G/KG/12HR
ACROSS THE COASTAL WATERS AND NORTH COASTAL GEORGIA THIS MORNING.
THIS HAS ALLOWED SOME SHOWER ACTIVITY TO DEVELOP AND MOVE ONSHORE
THIS MORNING. THE H3R AND RAP IDENTIFIED THIS ACTIVITY RATHER WELL
AND MAINTAIN A STREAM OF ISOLATED SHOWERS MOVING ONSHORE FOR MUCH
OF THE DAY...MAINLY FROM HILTON HEAD SOUTH INTO SOUTHEAST GEORGIA.
HAVE ADJUSTED POPS FOR THE LATE MORNING UPDATE TO MATCH GOING
NEAR TERM AND MODEL TRENDS...EXTENDING SLIGHT CHANCE POPS FROM THE
CHARLESTON COUNTY BEACHES INTO SOUTHEAST GEORGIA. SLIGHT CHANCE
POPS ARE ONLY SHOWN THROUGH EARLY AFTERNOON FOR CHARLESTON COUNTY
AND COASTAL COLLETON AS THE BEST SURFACE MOISTURE CONVERGENCE IS
EXPECTED TO REMAIN TO THE SOUTH...BUT THIS MAY NEED TO BE
READJUSTED LATER TODAY ONCE MESOSCALE TRENDS BECOME MORE APPARENT.
OTHERWISE...EXPECT DRY CONDITIONS INLAND TODAY WITH HIGHS RANGING
FROM THE LOWER 90S INLAND TO MID 80S AT THE BEACHES. IT WILL ALSO
BE RATHER BREEZY FROM ROUGHLY TYBEE ISLAND SOUTH TO SAPELO ISLAND
WITH WINDS 15-25 MPH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
TONIGHT...SURFACE HIGH PRESSURE WILL CONTINUE NORTH OF THE AREA
WHILE ANOTHER WEAK COASTAL TROUGH DEVELOPS AGAIN. SOME DEEPER
MOISTURE SHIFTING TOWARD THE COAST ON THE NORTH SIDE OF THE UPPER
LOW ALONG WITH THE SURFACE TROUGH SHOULD PRODUCE A BIT MORE IN THE
WAY OF SHOWERS AND POSSIBLY A FEW THUNDERSTORMS OVER THE ATLANTIC
WHICH WILL SHIFT TOWARD THE COAST LATE...MAINLY IN GEORGIA. LOWS
SHOULD REACH THE MID/UPPER 60S INLAND WITH MID 70S AROUND THE
COASTAL AREAS.
WEDNESDAY THROUGH FRIDAY...AN INVERTED UPPER LEVEL TROUGH WILL
RETROGRADE TOWARD THE SOUTHEAST U.S. COAST ON WEDNESDAY...CAUSING
THE EASTERN PERIPHERY OF THE UPPER LEVEL RIDGE OVER THE REGION TO
ERODE. THE INVERTED TROUGH WILL THEN BECOME ABSORBED INTO A LARGER
LONGWAVE TROUGH DIGGING INTO THE EASTERN U.S. ON THURSDAY AND
FRIDAY. MEANWHILE AT THE SURFACE...HIGH PRESSURE WILL BUILD INTO
THE REGION FROM THE NORTH ON WEDNESDAY...WITH ITS AXIS THEN
SHIFTING ACROSS THE AREA ON THURSDAY BEFORE IT BECOMES ESTABLISHED
OVER THE WESTERN ATLANTIC AHEAD OF A NEARING BACKDOOR COLD FRONT
ON FRIDAY.
STRONG SUBSIDENCE AND A LACK OF DEEP MOISTURE WILL PREVENT THE
FORMATION OF ANY CONVECTION INTO FRIDAY MORNING...ALTHOUGH SLIGHTLY
ENHANCED LOW LEVEL CONVERGENCE OFFSHORE COULD SUPPORT A FEW
SHOWERS/THUNDERSTORMS AT TIMES. TRAJECTORIES COULD ALLOW AN ISOLATED
SHOWER/THUNDERSTORM TO ADVECT INLAND ALONG PORTIONS OF THE IMMEDIATE
GEORGIA COAST...BUT OVERALL PROBABILITIES ARE LOW. MOISTURE SHOULD
INCREASE SUFFICIENTLY AHEAD OF THE APPROACHING BACKDOOR COLD FRONT
TO SUPPORT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS FRIDAY
AFTERNOON...WITH THE GREATEST COVERAGE ACROSS SOUTHEAST SOUTH
CAROLINA.
HIGH TEMPERATURES WILL REMAIN AROUND 90 INLAND FROM COOLER COASTAL
AREAS...WITH LOWS RANGING FROM THE MID 60S WELL INLAND TO THE LOWER
AND MID 70S NEAR THE IMMEDIATE COAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
MEDIUM RANGE GUIDANCE REMAINS IN VERY GOOD AGREEMENT FOR MOST OF THE
LONG TERM PERIOD. A LONGWAVE UPPER LEVEL TROUGH WILL PREVAIL OVER
THE EASTERN U.S. THROUGH SATURDAY...BEFORE LIFTING OUT TO THE
NORTHEAST AND ALLOWING A RIDGE AND/OR MORE ZONAL FLOW TO DEVELOP
ALOFT AND PREVAIL INTO EARLY NEXT WEEK. AT THE SURFACE...A BACKDOOR
COLD FRONT WILL DROP THROUGH THE AREA FRIDAY NIGHT...THEN BECOME
NEARLY STATIONARY SOMEWHERE ACROSS FAR SOUTHERN GEORGIA OR NORTHERN
FLORIDA INTO EARLY NEXT WEEK AS IT BECOMES ALIGNED WITH THE FLOW
ALOFT. BEHIND THE FRONT...HIGH PRESSURE WILL BUILD INTO THE REGION
FROM THE NORTH.
AS FOR EXPECTED WEATHER...THERE IS A CHANCE FOR SHOWERS AND
THUNDERSTORMS TO ACCOMPANY THE PASSAGE OF THE FRONT FRIDAY NIGHT
WITH LINGERING MOISTURE BEHIND THE FRONT KEEPING EITHER A SLIGHT
CHANCE OR CHANCE OF SHOWERS IN THE FORECAST FOR SATURDAY. THE
PROXIMITY OF THE FRONT AND LOW LEVEL TRAJECTORIES WILL FAVOR KEEPING
A SLIGHT CHANCE OF PRECIPITATION IN THE FORECAST INTO EARLY NEXT
WEEK FOR PORTIONS OF SOUTHEAST GEORGIA AND FAR SOUTHERN SOUTH
CAROLINA...BUT ESPECIALLY ALONG THE SOUTHEAST GEORGIA COAST.
SIGNIFICANTLY COOLER TEMPERATURES WILL OCCUR FOLLOWING THE PASSAGE
OF THE BACKDOOR COLD FRONT...WITH A NORTHEAST FLOW ONLY SUPPORTING
HIGHS IN THE LOWER TO MID 80S OVER THE WEEKEND. TEMPERATURES WILL
THEN BEGIN TO MODERATE EARLY NEXT WEEK.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS ARE EXPECTED AT KCHS AND KSAV THROUGH 12Z WEDNESDAY.
GIVEN THE DEEP EASTERLY FLOW THERE IS THE POTENTIAL FOR A FEW
SHOWERS/TSTMS TODAY...MAINLY AT KSAV WHERE DEEPER MOISTURE WILL BE
FOUND. HOWEVER...PROBABILITIES ARE TO LOW TO INCLUDE IN THE TAFS
AT THIS TIME.
EXTENDED AVIATION OUTLOOK...THERE ARE NO CONCERNS WITH A GREATER
THAN 30 PERCENT CONFIDENCE.
&&
.MARINE...
TODAY...MODEST WIND SURGE IS ONGOING ACROSS THE WATERS THIS
MORNING WITH SPEEDS ROUGHLY 15-20 KT...EXCEPT 15 KT OFF THE
CHARLESTON COUNTY COAST. RAP/H3R SHOW 15-20 KT WINDS HOLDING FOR
MUCH OF THE DAY. SEAS WILL BUILD SLIGHTLY...3-4 FT MOST ZONES.
TONIGHT...HIGH PRESSURE WILL REMAIN NORTH OF THE AREA WITH MOSTLY
EAST WINDS 15 KNOTS OR LESS AND SEAS UP TO 3 FT WITHIN 20 NM AND
UP TO 4 FT IN THE 20-60 NM GEORGIA ZONE.
WEDNESDAY THROUGH SUNDAY...HIGH PRESSURE WILL PERSIST OVER THE
WATERS THROUGH WEDNESDAY NIGHT...MAINTAINING QUIET CONDITIONS. THE
FLOW WILL BECOME MORE SOUTHERLY THURSDAY AND FRIDAY AHEAD OF AN
APPROACHING COLD FRONT...WHICH IS EXPECTED TO DROP ACROSS THE WATERS
LATE FRIDAY AND FRIDAY NIGHT. A STRONG NORTHEAST SURGE WILL THEN
OCCUR IN WAKE OF THE FRONT SATURDAY AND SUNDAY...LIKELY RESULTING IN
SMALL CRAFT ADVISORY CONDITIONS OVER MOST OF THE WATERS. SEAS WILL
GENERALLY BE NO HIGHER THAN 2-4 FT...GREATEST OVER THE OUTER GEORGIA
WATERS...THROUGH FRIDAY BEFORE INCREASING A COUPLE OF FEET OVER THE
WEEKEND AS THE STRONG NORTHEAST FLOW DEVELOPS AND THE FETCH
INCREASES.
RIP CURRENTS...WINDS ARE BEEN AVERAGING 15-20 MPH ALONG THE
GEORGIA BEACHES THIS MORNING WITH OCCASIONAL HIGHER GUSTS. RAP/H3R
KEEP BREEZY CONDITIONS IN PLACE AS ISOLATED SHOWERS MOVE INLAND
THROUGHOUT THE DAY. THIS COUPLED WITH 3 FOOT SEAS AND PERIODS
AROUND 8 SECONDS WILL SUPPORT A LOW-END MODERATE RISK FOR RIP
CURRENTS THROUGH EARLY THIS EVENING. WILL MAINTAIN A LOW RISK FOR
THE SOUTH CAROLINA BEACHES GIVEN THE SLIGHTLY LOWER WIND SPEEDS
THAT ARE EXPECTED...BUT THIS WILL BE MONITORED THROUGHOUT THE DAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
746 AM EDT TUE SEP 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 527 AM EDT TUE SEP 10 2013
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...THE MID LEVEL LOW THAT
WAS OVER THE PACIFIC NW FOR SEVERAL DAYS IS NOW AN OPEN WAVE OVER
THE DAKOTAS INTO SRN MANITOBA. AT THE SFC...A LOW PRES TROF EXTENDS
FROM NW MN ACROSS LAKE SUPERIOR.
INITIALLY...WILL HAVE TO DEAL WITH SOME FOG EARLY THIS MORNING WHICH
WILL BE LOCALLY DENSE. WITH WESTERLY WINDS S OF THE SFC TROF
INCREASING A BIT OVER THE NEXT FEW HRS...FOG SHOULD CLEAR OUT OF THE
AREAS THAT SEE DOWNSLOPING WITH A W WIND. WHERE WINDS UPSLOPE...FOG
WILL DISSIPATE BY LATE MORNING UNDER A COMBINATION OF DAYTIME
HEATING AND MECHANICAL MIXING WITH INCREASING LOW-LEVEL WINDS. AS OF
09Z...KMQT RADAR DOES NOT SHOW ANY PCPN ACROSS THE FCST AREA.
HOWEVER...RIGHT ENTRANCE OF WSW TO ENE ORIENTED UPPER JET ASSOCIATED
WITH DAKOTAS/MANITOBA SHORTWAVE IS SUPPORTING A BKN BAND OF SHRA
FROM THE NEBRASKA TO NE MN. SOME OF THESE SHRA AND PERHAPS A TSRA
MAY AFFECT MAINLY WRN UPPER MI THIS MORNING AS UPPER JET TRANSLATES
EASTWARD. THIS AFTN...ATTENTION TURNS TO THE ERN FCST AREA AS
DAYTIME HEATING/LOW-LEVEL MOISTURE LEAD TO MLCAPE INCREASING TO
500-1000J/KG. WESTERLY LOW-LEVEL WINDS WILL LEAD TO ENHANCED
CONVERGENCE ACROSS INTERIOR ERN UPPER MI AS WINDS VEER NEAR LAKE
SUPERIOR AND BACK NEAR LAKE MICHIGAN AS LAKE BREEZE COMPONENT
DEVELOPS. EXPECT SCT SHRA/TSRA TO DEVELOP ROUGHLY ALONG A LINE
MIDWAY BTWN ESCANABA/MUNISING E TO NEWBERRY. ISOLATED SHRA/TSRA MAY
DEVELOP AS FAR W AS TOWARD KSAW/KIMT. AS FOR TEMPS...WITH INCREASING
W WINDS...DOWNSLOPE AREAS WILL SEE LOW CLOUDS CLEAR OUT THIS
MORNING. THIS WILL LIKELY LEAD TO A HOT/HUMID DAY OVER SCNTRL UPPER
MI AS DOWNSLOPING ENHANCES THE ALREADY VERY WARM START TO THE DAY.
MIXING TO 850-800MB ON NAM/GFS FCST SOUNDINGS SUGGESTS POTENTIAL FOR
MAX TEMPS INTO THE LOW/MID 90S OVER THE SCNTRL. SOME CLOUD COVER
THIS AFTN MAY LIMIT MIXING DEPTH...BUT DOWNSLOPING COULD STILL
SUPPORT TEMPS OVER 90F. FOR NOW...RAISED MAX TEMPS TO THE UPPER 80S
OVER THE SCNTRL WITH LOWER 80S EXTENDING INTO THE INTERIOR ERN FCST
AREA. ELSEWHERE...70S SHOULD BE THE RULE...THOUGH TEMPS MAY TOP 80F
WHERE W WINDS DOWNSLOPE.
AS UPPER JET CONTINUES TO TRANSLATE EASTWARD TONIGHT...RIGHT
ENTRANCE OF JET WILL AID A RIBBON OF LOW-MIDLEVEL FRONTOGENESIS
ACROSS THE UPPER LAKES. CONSENSUS OF MODEL GUIDANCE SHOWS THIS
FORCING SUPPORTING A BAND OF SHRA STREAKING ENE ACROSS WI TOWARD THE
STRAITS. THERE IS SOME UNCERTAINTY IN EXACTLY WHERE THIS RELATIVELY
NARROW BAND OF PCPN WILL BE LOCATED...BUT BULK OF GUIDANCE SUGGESTS
THE FAR SCNTRL/SE FCST AREA WILL BE CLIPPED. OPTED TO INCLUDE LOW
CHC POPS IN THAT AREA. SOME OF THE HIGHER RESOLUTION MODEL GUIDANCE
ALSO INDICATE LATE AFTN SHRA OVER NRN MN MAKING IT ACROSS LAKE
SUPERIOR AND AFFECTING WRN UPPER MI THIS EVENING. INCLUDED SCHC POPS
OVER THE W THIS EVENING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 525 AM EDT TUE SEP 10 2013
OUR ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH THURSDAY. WE WILL
FINALLY DISPLACE THE 500MB TROUGH THAT HAS BEEN BEEN SET UP ACROSS
THE NORTHERN TIER OF CENTRAL AND EASTERN U.S. FRIDAY NIGHT THROUGH
THE START OF THE UPCOMING WEEKEND...AS THE RIDGE MOVES OVERHEAD.
STARTING OUT AT 12Z WEDNESDAY...THE SFC LOW OVER N ONTARIO WILL BE
DRAGGING A COLD FRONT ACROSS MN AND FAR W LAKE SUPERIOR. MAINLY
AFTERNOON CONVECTION IS EXPECTED AS THE COLD FRONT DRAGS ACROSS THE
AREA...WITH THE ASSIST OF DAYTIME HEATING. ML CAPE VALUES TO OUT
AROUND 500J/KG OR LESS WEDNESDAY AFTERNOON OVER THE E HALF TO
TWO-THIRDS OF UPPER MI...AND QUICKLY DIMINISH TOWARD 00Z.
LARGE HIGH PRESSURE OVER S CENTRAL CANADA AND THE N PLAINS WEDNESDAY
NIGHT/THURSDAY MORNING WILL THEN BE THE MAIN INFLUENCE ON OUR
WEATHER FOR THE END OF THE WEEK. STRONG N WINDS /SLOWED DOWN APPROX
3-6HRS/ STILL LOOK REASONABLE...USHERING IN COLD AIR ACROSS LAKE
SUPERIOR AND UPPER MI.
THE COLDEST AIR OVERHEAD LOOKS TO BE SET UP AROUND 06Z FRIDAY...WITH
850MB TEMPS FALLING TO 1 TO -4C /COOLEST OFF THE ECMWF/. WHILE THERE
REMAINS THE POTENTIAL FOR FROST DEVELOPMENT...WITH THE COLD AIR
OVERHEAD AND PW VALUES FALLING TO AROUND 45 PERCENT OF NORMAL
/0.3-0.4IN/...N-NNE WINDS OFF LAKE SUPERIOR MAY STILL BE BRINGING
LOW CLOUDS AND EVEN LAKE ENHANCED RAIN SHOWERS/DRIZZLE ON N-NNE
WINDS OFF LAKE SUPERIOR.
AS FOR THE FROST POTENTIAL FOR FRIDAY NIGHT INTO SATURDAY
MORNING...WITH THE SFC HIGH SLIDING TO S CENTRAL AND EASTERN UPPER
MI...THE LIGHTEST WINDS WILL BE THERE. PW VALUES WILL NOT BE QUITE
AS LOW...IN THE 0.4-0.5 RANGE OR AROUND 50 PERCENT OF NORMAL. THESE
SLIGHTLY HIGHER PW VALUES AND 850MB TEMPS AROUND 5C WILL BE OFFSET
BY THE LIGHTER WINDS AND CLEAR SKY...WITH SIMILAR TEMP READINGS
EXPECTED ACROSS CENTRAL AREAS.
LOOK FOR A TEMPORARILY BREAK TO THE COOL WEATHER ON SATURDAY AND TO
A LESSER EXTENT SUNDAY...AS HIGHS TOP OUT IN THE 60S. THIS IS STILL
4-10F BELOW NORMAL FOR THIS TIME OF YEAR. WAA ON WSW WINDS SATURDAY
SHOULD ALLOW 850MB TEMPS TO RISE TO 8-10C. SUNDAY WILL BE A
DIFFERENT STORY...AS A SHORTWAVE LOOKS TO PUT AN END TO OUR DRY
WEATHER ON SUNDAY. SLOWED DOWN OUR INITIAL BLEND FOR THE EXTENDED
PERIOD...BUT LOOKING AT THE LATEST 10/00Z GFS/ECMWF RUNS. IN
FACT...THE SCATTERED POPS FOR SATURDAY NIGHT THROUGH SUNDAY LOOK TO
BE IN JEOPARDY IF THE 10/00Z GFS IS CORRECT...AS IT KEEPS US DRY
THROUGH AT LEAST NEXT MONDAY. WILL WAIT TO SEE HOW THE NEXT COUPLE
RUNS PLAY UP THIS FEATURE BEFORE MAKING TOO MANY CHANGES TO THE
ONGOING FCST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 745 AM EDT TUE SEP 10 2013
LIFR/IFR CONDITIONS IN FOG/STRATUS WILL START THE FCST AT
KIWD/KCMX/KSAW. THEN...INCREASING WESTERLY FLOW AND DAYTIME HEATING
WILL WORK TO MIX OUT THE LOW-LEVEL MOISTURE THIS MORNING INTO THE
EARLY AFTN. UPSLOPE NATURE OF THE FLOW AT KCMX SHOULD RESULT IN
IMPROVEMENT BEING SLOWEST THERE THAN AT KIWD/KSAW...BUT ALL
TERMINALS WILL BE VFR BY MID AFTN. BAND OF SHRA OVER CNTRL MN INTO
NW WI MAY HOLD TOGETHER AND AFFECT KIWD/KCMX THIS MORNING. VFR
CONDITIONS SHOULD CONTINUE TONIGHT...BUT WILL NEED TO WATCH FOR THE
POTENTIAL OF FOG REDEVELOPMENT...ESPECIALLY IF SKIES BECOME MOSTLY
CLEAR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 318 AM EDT TUE SEP 10 2013
PATCHY TO AREAS OF FOG SHOULD SLOWLY DISSIPATE THIS MORNING. LOW
PRESSURE EXITING E LAKE SUPERIOR TODAY WILL BE REPLACED BY A BROAD
TROUGH THAT WILL BE EXTENDING SOUTHWARD FROM NORTHERN ONTARIO LATE
TONIGHT THROUGH EARLY WEDNESDAY EVENING. A LARGE HIGH PRESSURE
ENCOMPASSING MUCH OF S CENTRAL CANADA AND THE N PLAINS WEDNESDAY
NIGHT WILL SLOWLY DRIFT ACROSS THE UPPER GREAT LAKES FRIDAY INTO
SATURDAY...BEFORE EXITING TO THE LOWER GREAT LAKES AND THE E COAST
FOR THE LATTER HALF OF THE WEEKEND. THE STRONGEST WINDS OVER LAKE
SUPERIOR...OUTSIDE OF THUNDERSTORMS...WILL BE THURSDAY MORNING
THROUGH EARLY FRIDAY MORNING...WITH NW GUSTS OF 20-30KTS CENTERED
ACROSS MAINLY CENTRAL AND E LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
633 AM CDT TUE SEP 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT TUE SEP 10 2013
A RATHER CONVOLUTED SURFACE/UPPER AIR PATTERN OVER THE REGION THIS
MORNING. CENTERS OF LOW PRESSURE WERE NOTED OVER NORTHERN WI...
NORTHERN MN AND ND. A LEAD COLD FRONT MEANDERED FROM NORTHERN WI
THROUGH SE MN AND EASTERN NE WHILE A SECONDARY COLD FRONT CURVED
ACROSS THE DAKOTAS. A THIRD AND REAL COLD FRONT WAS ACROSS SOUTH
CENTRAL CANADA... WHICH THE LONG TERM WILL DISCUSS BELOW. UPSTAIRS...
SUBTROPICAL MOISTURE WAS FLOWING NORTHEAST ACROSS THE CWA FROM THE
DESERT SOUTHWEST. A WAVE IN THE SUBTROPICAL FEED WAS NOTED OVER
WESTERN NE. THIS FEATURE IS PROGGED OVER SE MN BY THIS EVENING. A
LITTLE FURTHER NORTHWEST... A TROUGH IN THE POLAR JET WAS NEARING
THE ND/MN BORDER. THE DAY AHEAD WILL FEATURE INCREASING MID LEVEL
FRONTOGENESIS SPREADING NORTHEAST FROM SD/NE... THE INTERACTION
BETWEEN THE TWO WAVES ALOFT. SOME SHOWERS AND ISOLATED
THUNDERSTORMS HAVE ALREADY SPREAD INTO SOUTHWEST AND WEST CENTRAL
MN EARLY THIS MORNING. ALTHOUGH THE ACTIVITY IS MOVING NE A SLIGHT
NORTHWARD DRIFT IS SEEN IN THE OVERALL PATTERN. VARIOUS MODEL
SOLUTIONS SHOW PLENTY OF LAYER RH ALONG WITH THE MID LEVEL
FRONTOGENESIS. HOWEVER...LITTLE TO NO QPF IS PRODUCED WHICH DOES
NOT SEEM RIGHT WHEN LOOKING AT THE ADIABATIC OMEGA AND
SATURATION ON THE 305/310K THETA SURFACES. THE NAM PRODUCES THE
MOST QPF BUT APPEARS TO BE TOO FAR SOUTH INITIALLY. THE PAST FEW
RUNS OF THE HRRR MATCH WELL WITH THE TRENDS AND WOULD SUGGEST THAT
THE SHOWERS AND ISOLATED THUNDERSTORMS OVER WEST CENTRAL MN WILL
MOVE NORTHEAST THIS MORNING WITH A PERIOD OF DRYING IN THEIR WAKE.
THEN...MORE SHOWERS DEVELOP THIS AFTERNOON ACROSS SOUTHERN MN AND
ADJOINING AREAS OF WEST CENTRAL WI AS THE WAVE FROM NE ARRIVES AND
THE MID LEVEL FRONTOGENESIS BEGINS SLIPPING SOUTH. THE SHOWERS
SHOULD THEN END THIS EVENING OVER FAR EASTERN AND SOUTHERN AREAS
FOLLOWED BY DECREASING CLOUDINESS. HIGHS TODAY WILL BE TIED TO THE
CLOUDS AND SHOWERS. THE WARMEST AREAS WILL STRETCH FROM SOUTH
CENTRAL MN THROUGH KEAU WHERE MIDDLE 80S ARE LIKELY. TO THE NORTH
AND WEST... MIDDLE 70S TO LOWER 80S ARE FORECAST. IT WILL STILL BE
MILD TONIGHT WITH LOWS IN THE UPPER 50S TO MIDDLE 60S BUT THAT
WILL CERTAINLY BE CHANGING FOR WEDNESDAY AND THURSDAY MORNINGS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 345 AM CDT TUE SEP 10 2013
MODEL AGREEMENT ON THE EVOLUTION OF THE UPPER AIR PATTERN IS HIGH
THROUGH THE COURSE OF THE WORK WEEK...BUT BEGIN TO DIVERGE
SIGNIFICANTLY OVER THE WEEKEND. DURING THE WEEK...WE WILL SEE A
RE-AMPLIFICATION OF WHAT HAS BECOME THE ALL TOO FAMILIAR H5 PATTERN
SINCE MID JULY OF A WRN NOAM RIDGE AND ERN NOAM THROUGH...WITH NW
FLOW FOR US STUCK IN THE MIDDLE. WITHIN THE RIDGE...A MONSOONAL WAVE
CURRENTLY OVER THE FOUR CORNERS WILL SLOWLY DRIFT NE INTO THE NRN
PLAINS THIS WEEKEND. FROM THERE...TWO DIFFERENT STORIES APPEAR. THE
PROTAGONIST IN BOTH OF THESE STORIES IS A NRN STREAM WAVE THAT WILL
BE WORKING ACROSS THE TOP OF THE RIDGE OVER SRN CANADA THIS WEEKEND.
THE 10.00 ECMWF...10.00 GEM...AND 09.12 GFS DIG THIS NRN WAVE FAR
ENOUGH SOUTH TO PICK UP THE MONSOONAL DISTURBANCE...AND DRIVE A
FAIRLY POTENT POSITIVELY TITLED THROUGH THE GREAT LAKES/UPPER MS
VALLEY SAT NIGHT. THE 10.00 GFS AND 09.12 ECMWF KEEP THIS NRN STREAM
WAVE FAR ENOUGH NORTH THAT THE MONSOONAL WAVE IS LEFT TO WANDER OVER
THE NRN PLAINS WITHIN THE RIDGE FOR THE WEEKEND INTO NEXT WEEK. AS
YOU CAN IMAGINE...WITH THE ECMWF/GFS SWAPPING THEIR POSITIONS
BETWEEN THE 09.12 AND 10.00 RUNS...CONFIDENCE IN THE FORECAST BEGINS
TO DECREASE CONSIDERABLY THIS WEEKEND.
AT THE SFC...WEDNESDAY WILL FEATURE THE PASSAGE OF A SECONDARY COLD
FRONT...THAT WILL GIVE WAY TO COOL/DRY HIGH PRESSURE FOR THU/FRI.
RETURN FLOW SETS UP FOR SATURDAY...WITH RAIN CHANCES RETURNING AS A
RESULT. THE CURRENT RUN OF THE ECMWF /OLD GFS/ DRIVE ANOTHER FRONT
THROUGH SAT NIGHT/SUNDAY...WHILE THE OLD ECMWF /NEW GFS/ KEEP A
MOIST SRLY FETCH GOING THROUGH THE WEEKEND AND INTO NEXT AS THE
MONSOONAL WAVE SITS AND SPINS OVER THE NRN PLAINS.
FOR TEMPERATURES...WEDNESDAY WILL BE THE WARMEST DAY...AS 925-850 MB
TEMPS CONTINUE TO RUN BETWEEN 16C AND 20C. A MAINLY SUNNY DAY IS
EXPECTED IN THE WAKE OF ALL OF TODAY/TONIGHTS WAVINESS...AND MIXING
THESE TEMPS DOWN SUPPORTS HIGHS IN THE LOW/MID 80S. THE SECONDARY
COLD FRONT CLEARING THE AREA WEDNESDAY NIGHT WILL SEND 925-850 MB
TEMPS BACK INTO THE SINGLE DIGITS...WHICH WILL BRING BACK
TEMPERATURES SLIGHTLY BELOW NORMAL TO END THE WEEK. IN ADDITION...
ON FRIDAY MORNING...HIGH PRESSURE WILL BE OVER/AROUND WRN LAKE
SUPERIOR AND THE COMBO OF CLEAR SKIES AND CALM WILL GIVE US OUR
FIRST SHOT AT SEEING SOME FROST /WITH LOWS INTO THE MID 30S/ ACROSS
RUSK/BARRON/DUNN/CHIPPEWA COUNTIES IN WI. BY THE WEEKEND...
TEMPS/THICKNESSES WILL INCREASE...BUT THE RETURN OF CLOUD COVER WILL
HELP HOLD HIGHS BACK AROUND NORMAL...WHICH ARE ALREADY DOWN INTO THE
LOW/MID 70S.
AS FOR PRECIP...MODELS HAVE BEEN TRENDING SLOWER WITH ITS RETURN
OVER THE WEEKEND...SO SLOWED THE EASTWARD ADVANCEMENT OF POPS ACROSS
THE AREA ON SATURDAY AS A RESULT. THE HIGHER POPS IN THE FORECAST
SAT NIGHT INTO SUNDAY WOULD FAVOR THE 10.00 ECMWF SOLUTION...BUT THE
IMPACT OF THE 10.00 GFS /ALONG WITH THE 09.12 ECMWF/ WAS TO HAVE
SLIGHTS CONTINUE INTO MONDAY. DOES NOT LOOK PRECIP AMOUNTS WOULD BE
OVERWHELMING WITH THIS SYSTEM...BUT CONSIDERING MSP HAS ONLY
MEASURED 9 HUNDREDTHS OF AN INCH OF RAIN SINCE 1.33 INCHES FELL ON
AUGUST 6TH...WE WILL TAKE ANYTHING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM CDT TUE SEP 10 2013
STILL DEALING WITH SOME FINGERS OF MVFR CIGS JUST TO THE NORTH AND
EAST OF KSTC AND KMSP EARLY THIS MORNING. THE TREND THE PAST FEW HOURS
HAS BEEN FOR SOME CONTRACTION OFF TO THE NORTHEAST. PART OF THIS
MAY BE DUE TO THE LOW LEVEL FLOW BACKING IN ADVANCE OF THE NEXT
COOL FRONT ACROSS NW MN. KRNH AND KEAU AT MOST RISK FOR BKN015
FOR A FEW HOURS THIS MORNING. SHOWERS HAVE BEEN ON THE INCREASE AS
WELL FROM WEST CENTRAL MN THROUGH KDLH OVERNIGHT AS A MID LEVEL WAVE
APPROACHES FROM THE CENTRAL PLAINS. SHORT TERM SOLUTIONS SUGGEST
THAT KSTC IS IN THE PATH OF -SHRA FOR A FEW HOURS THIS MORNING
WITH THE SOUTHERN EDGE OF THE ACTIVITY LIKELY SKIRTING KMSP AND
KRNH. A LULL IN THE SHOWERS THEN EXPECTED DURING THE LATE MORNING
AND EARLY AFTERNOON HOURS WITH MORE SHOWERS DEVELOPING NEAR A
KRWF - SOUTH TWIN CITIES METRO - KEAU LINE DURING THE AFTERNOON
AND THEN PUSHING OFF TO THE SOUTHEAST THIS EVENING. ISOLATED
THUNDER CAN/T BE RULED OUT. CEILINGS OUTSIDE OF EARLY THIS MORNING
WILL BE MORE SCT-BKN040-60 BKN-OVC080-100. WESTERLY WINDS UP TO 10
KNOT TODAY THEN DIMINISHING TO 6 KNOTS OR LESS TONIGHT. RISK FOR
MVFR FOG TONIGHT AT KSTC...KRNH AND KEAU WITH 3-5 SM INSERTED AT
THIS POINT AT 09Z.
KMSP...
EXPECT MVFR CIGS TO STAY JUST NORTHEAST OF THE AIRFIELD THIS
MORNING. SOME LIGHT RAIN/SPRINKLES WILL SKIRT THE AREA BETWEEN 13Z
AND 16Z. THERE IS ANOTHER THREAT FOR SHOWERS AND ISOLATED
THUNDERSTORMS IN THE 21Z-24Z TIME FRAME. WESTERLY WINDS TODAY
(260-290) AROUND 6 KNOTS THIS MORNING AND 10 KNOTS THIS AFTERNOON.
/OUTLOOK FOR KMSP/
WED...VFR. NW WINDS 10-15 KTS.
THU...VFR. N WINDS 10-15 KTS.
FRI...VFR. E WINDS 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...RAH
LONG TERM...MPG
AVIATION...RAH
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
624 AM CDT TUE SEP 10 2013
.AVIATION...12Z TAFS FOR KOMA...KLNK AND KOFK. VFR CONDITIONS AT
ALL TAF SITES THROUGH THE PERIOD. A COLD FRONT WILL CONTINUE TO
SLOWLY DRIFT SOUTHWARD THROUGH THE REGION TODAY. THE FRONT WAS
ALREADY PAST KOFK WITH A LIGHT NORTHERLY WIND...AND SHOULD REACH
KOMA/KLNK BY 01-02Z. PRECIP CHANCES APPEAR BEST AT KOMA/KLNK WITH
THE ARRIVAL OF THE FRONT AND OPTED FOR A 6 HOUR WINDOW WITH A 30
PERCENT CHANCE OF SHOWERS AT THOSE 2 LOCATIONS. PRECIP CHANCES AT
KOFK APPEARED TOO LIMITED TO MENTION IN THE TAF AT THIS TIME.
DEWALD
&&
.PREV DISCUSSION... /ISSUED 356 AM CDT TUE SEP 10 2013/
DISCUSSION...
FORECAST CONCERNS THROUGH WEDNESDAY EVENING WILL BE PRECIPITATION
COVERAGE ALONG AND BEHIND THE COLD FRONT...THEN COOLER AND DRIER
WEATHER THURSDAY AND FRIDAY.
LINCOLN TIED THEIR RECORD OF 100 DEGREES MONDAY SET BACK IN 1931.
OMAHA EPPLEY JUST MISSED THE RECORD WITH A HIGH OF 99 AND NORFOLK
TOPPED OUT AT 97. OMAHA DID TIE A RECORD WARM MINIMUM FOR MONDAY
WITH 75 DEGREES (TIED WITH 1983/1931 AND 1927).
THE 00Z UPPER AIR MAPS HAD A 90KT H3 JET OVER NORTH DAKOTA WITH THE
H5 TROF SIMILARLY OVER NORTH DAKOTA...EXTENDING SOUTHWEST TOWARD
ARIZONA AND SOUTHERN CALIFORNIA. WARM H7 TEMPERATURES OF +10 TO +13C
EXTENDED ACROSS MUCH OF THE CENTRAL PLAINS...WITH THE THERMAL
GRADIENT FROM NORTHWEST NEBRASKA NORTHWARD ACROSS THE NORTHERN
PLAINS. H7 MOISTURE WAS NOTED ON THE WATER VAPOR IMAGERY AND UA
CHARTS FROM THE SOUTHWEST U.S. INTO THE UPPER MIDWEST. AT H85 THE
THERMAL RIDGE EXTENDED FROM SOUTHWEST NEBRASKA AND NORTHWEST KANSAS
NORTHEAST ACROSS THE FORECAST AREA WITH THE GRADIENT COMPARABLE TO
THE H7 PATTERN ACROSS THE DAKOTAS. ALTHOUGH THE SURFACE FRONT HAS
PUSHED INTO THE CWA AND THE OAX RADAR SHOWED A BOUNDARY
APPROACHING VALLEY WITH A WIND SHIFT AT KFET. THE SURFACE WINDS
WERE LIGHT FROM THE SOUTH AT KOFK AGAIN. THE WSR-88D MOSAIC HAD
THE LEADING EDGE OF THE PRECIPITATION FROM BROKEN BOW TO MITCHELL
SOUTH DAKOTA INTO SOUTHWEST MINNESOTA AT 06Z AND BY 0830Z THERE
WERE A FEW ECHOES IN BOYD AND KNOX COUNTIES...BUT NOT MUCH
REACHING THE GROUND. THE TREND ON THE IR SATELLITE LOOP SHOWED
EXPANDING/COOLING TOPS WITH THE PRECIPITATION. WPC HAD THE
EXCESSIVE DAY 1 RAINFALL OVER THE SOUTHWEST U.S. INTO WESTERN
COLORADO.
TODAY...THE NORTHERN PLAINS SHORT WAVE TROF WILL CONTINUE TO SHIFT
EAST ACROSS MINNESOTA INTO WISCONSIN...WHILE THE H5 LOW OVER THE
SOUTHWEST U.S. CUTS OFF. THIS WILL SLOW THE PUSH OF THE FRONT TO
SOMEWHERE ALONG I80 THROUGH 00Z. THE LOW LEVEL JET WILL STRENGTHEN
THIS ACROSS NORTH CENTRAL KANSAS INTO CENTRAL NEBRASKA AND THE
OAX FORECAST AREA...WITH ISENTROPIC LIFT AND SATURATION NORTH OF
THE FRONT IN PARTS OF NORTHEAST NEBRASKA. THE FORCING THIS
MORNING WILL MAINLY BE NORTHWEST OF THE FORECAST AREA BUT COULD
CLIP THE COUNTIES NEAR THE SD BORDER. FARTHER SOUTH THE FORCING
IS MORE NEGLIGIBLE. THE MODELS ARE HINTING AT A SECOND AREA OF
SATURATION FARTHER SOUTH CLOSER TO I80...BUT FOR NOW WILL INCREASE
CLOUDS AND MAY INCLUDE SPRINKLES MENTION. THIS AFTERNOON...THERE
IS WEAK CONVERGENCE ALONG THE FRONT AND A DECENT THERMAL BOUNDARY
IS EXPECTED. MODELS KEEP IS MAINLY DRY...HOWEVER HRRR DOES
GENERATE PRECIP ALONG THE FRONT. WILL MAINTAIN ISOLATED POPS ALONG
AND BEHIND THE FRONT WHERE DEEPER MOISTURE IS PRESENT WITH COOLING
ALOFT. TEMPERATURES TODAY SHOULD BE HOT AHEAD OF THE FRONT AND
WHERE THERE IS SUNSHINE. CLOUDS WILL IMPACT HIGHS...BUT GENERALLY
HAVE READINGS AROUND 80 NORTH NEAR THE SD BORDER TO THE UPPER 90S
NEAR THE MISSOURI AND KANSAS BORDERS.
TONIGHT THROUGH WEDNESDAY NIGHT THE MID TROPOSPHERIC TROF
DEEPENS OVER THE GREAT LAKES AND THE SURFACE FRONT IS PUSHED
FARTHER SOUTH. MONSOONAL MOISTURE STREAMING INTO THE ROCKIES AND
MAKING IT INTO THE PLAINS...POOLING AHEAD OF THE TROF COMBINE WITH
THE LOW...MID AND UPPER LEVEL SUPPORT WILL PROVIDE AT LEAST SOME
CHANCES FOR PRECIPITATION DURING THE PERIOD...ALTHOUGH COVERAGE
STILL LOOKS SCATTERED TO ISOLATED FOR THE COUNTY WARNING AREA.
HIGHS WEDNESDAY SHOULD RANGE FROM THE LOWER 80S NORTH TO THE LOWER
90S SOUTH.
COOL HIGH PRESSURE BUILDS IN FOR THURSDAY AND FRIDAY WITH MAINLY
DRY CONDITIONS. NEAR NORMAL HIGHS AROUND 80S THURSDAY WITH BELOW
NORMAL HIGHS IN THE 70S FRIDAY.
SATURDAY THROUGH TUESDAY...AS THE SURFACE HIGH
RETREATS...SOUTHWEST FLOW WILL RETURN DEEPER MOISTURE TO THE AREA
AND SHOWERS WILL TRY TO RETURN TO THE WESTERN CWA FRIDAY NIGHT.
SHORTWAVE TROF ENERGY ADVANCES INTO THE PLAINS SATURDAY THROUGH
SUNDAY...SO THERE APPEARS TO BE A GOOD SHOT AT PRECIPITATION
DURING THIS PERIOD. BEYOND THIS PERIOD...THERE IS NOT GOOD MODEL
CONSENSUS...BUT PRECIP CHANCES COULD LINGER INTO MONDAY. HIGHS
STILL BELOW NORMAL FOR MUCH OF THE EXTENDED.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1052 AM CDT TUE SEP 10 2013
.UPDATE...
SOME RR QUADRANT JET STREAK AND MID LEVEL FRONTAL ZONE CLOUDS
WILL STREAM OVER THE CWA FROM SOUTHWEST TO NORTHEAST THROUGH THE
DAY. ALSO...VISIBLE SATELLITE SHOWS STRATUS/STRATOCU CLOUDS
HEADING SOUTH INTO NORTHERN SD/WEST CENTRAL MN LATE THIS MORNING.
THESE ARE EXPECTED TO MIX OUT SOME AND BE MORE SCATTERED AS THEY
MOVE ACROSS THE EASTERN PART OF THE CWA. OVERALL...SKIES WILL BE
PARTLY CLOUDY THROUGH THE DAY WITH STEADY NORTHWEST BREEZES.
EXPECT ANY SHOWER/THUNDER ACTIVITY TO REMAIN SOUTH OF OUR CWA THIS
AFTERNOON ALONG THE FRONTAL ZONE. MIXED OUT HIGHS WILL BE AROUND
80 TO 85 DEGREES BY LATE AFTERNOON. FORECAST LOOKS GOOD.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH THURSDAY
A BAND OF RAIN SHOWERS CONTINUES ACROSS PARTS OF SOUTH CENTRAL
SOUTH DAKOTA THROUGH WEST CENTRAL MINNESOTA THIS MORNING. THIS IS
MAINLY INFLUENCING THE SIOUX FALLS CWA...HOWEVER...IT DOES REQUIRE
POPS ACROSS THE FAR SOUTHERN TIER OF COUNTIES THROUGH MOST OF THE
MORNING HOURS TODAY. THIS IS CURRENTLY THE ONLY CHANCE FOR
PRECIPITATION THROUGH THE SHORT TERM FORECAST...AS THE ENERGY
ASSOCIATED WITH THE UPPER SHORTWAVE TROUGH MOVES NORTHEAST INTO
THE ONTARIO REGION TODAY. NORTHWEST FLOW FOLLOWS....AND WILL
PREVAIL ACROSS THE DAKOTAS THROUGH THE SHORT TERM. ANOTHER TROUGH
DOES DROP OUT OF CANADA AND ACROSS NORTH DAKOTA ON WEDNESDAY...BUT
THE BEST FORCING WILL REMAIN NORTH AND EAST OF THIS CWA. AN
ASSOCIATED SURFACE COLD FRONT WILL DROP SOUTHWARD AS WELL. SO WITH
SLIGHTLY ABOVE NORMAL TEMPERATURES TODAY AND WEDNESDAY...TEMPERATURES
WILL DROP TO NEAR NORMAL VALUES ON WEDNESDAY NIGHT AND THURSDAY
BEHIND THE FRONT. THE SURFACE HIGH CENTER WILL REMAIN IN
CANADA...HOWEVER THE RIDGE WILL EXTEND ACROSS THE DAKOTAS AND
WINDS WILL GO LIGHT THURSDAY MORNING. ALONG WITH COLD AIR
ADVECTION AND CLEAR SKIES...THURSDAY MORNING LOWS WILL BE DROPPING
INTO THE MID 40S ACROSS THE NORTH. HIGHS ON THURSDAY WILL THEN BE
IN THE LOW TO UPPER 70S.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
A COOL/DRY CANADIAN-SOURCED AIRMASS SHOULD BE SETTING UP SHOP
ACROSS THE CWA AS THE PERIOD OPENS. A RATHER AMPLIFIED/BLOCKY
UPPER FLOW PATTERN WILL ONLY HAD ANOTHER LAYER OF FORECAST
DIFFICULTY TO SYSTEM TIMING/PLACEMENT/STRENGTH OVER THE WEEKEND AS
AN UPPER LOW DEPICTED IN WATER VAPOR IMAGERY OUT OVER ARIZONA
MEANDERS ITS WAY UP INTO THE CENTRAL/NORTHERN PLAINS. THE 00Z
GFS/CANADIAN/ECMWF DETERMINISTIC SOLUTIONS ALL CONTINUE TO SPREAD
PRECIPITATION UP INTO THE CWA LATE FRIDAY NIGHT. THE PRECIP SHIELD
THEN SLOWLY SPREADS NORTH AND EAST ACROSS THE CWA
SATURDAY/SATURDAY NIGHT. NOT A WHOLE LOT OF STEERING FLOW ALOFT
OVER THE CWA DURING THE EXTENDED FORECAST PERIOD. SO...IF THE RAIN
FORECAST PANS OUT...THERE IS CERTAINLY THE POTENTIAL FOR A
RAIN-COOLED BOUNDARY LAYER TO SATURATE BY SATURDAY NIGHT AND
PRODUCE EITHER FOG OR LOW STRATUS. WITHOUT A REAL NOTEWORTHY
PRESSURE FIELD/GRADIENT OR MIXING WIND ANTICIPATED...PARTIAL TO
WIDESPREAD STRATUS CONDITIONS COULD BE ADDING A NEW WRINKLE TO THE
FORECAST FOR SUNDAY/MONDAY.
DURING THE FORECAST PERIOD...TEMPERATURES ARE NOT EXPECTED TO STRAY
MORE THAN A FEW DEGREES EITHER SIDE OF CLIMO NORM FOR
MID-SEPTEMBER.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
ONE MORE RAIN SHOWER SHOULD BE AFFECTING THE KATY TERMINAL RIGHT
AT THE START OF THE TAF VALID PERIOD FOR JUST A SHORT WHILE.
THEN...ALL FOUR TERMINALS SHOULD SEE DRY CONDITIONS THROUGH
WEDNESDAY MORNING. THERE IS SOME IFR/MVFR STRATUS TRYING TO WORK
DOWN OUT OF NORTH DAKOTA EARLY THIS MORNING. COULD SEE A TEMPORARY
SUB-VFR STRATUS CEILING SPREADING OVER THE KABR TERMINAL THIS
MORNING AS THE MORNING SUN IS WORKING TO MIX THINGS OUT.
OTHERWISE...ALL FOUR TERMINALS SHOULD BE EXPERIENCING VFR FLYING
WEATHER CONDITIONS ON A LIGHT WEST-NORTHWEST WIND.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...SERR
LONG TERM...DORN
AVIATION...DORN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1011 AM CDT TUE SEP 10 2013
.DISCUSSION...LOWERED TEMPERATURES MAINLY SOUTHEASTERN SECTIONS
AND INCREASED POPS JUST A TAD OVER THE SOUTHERN COASTAL AREAS. RUC
AND HRRR IS SHOWING CONVECTION CONTINUING NEAR THE SOUTHERN
COASTAL AREAS FROM TIME TO TIME TIL EARLY AFTERNOON BEFORE MOST
OF IT PUSHES INLAND. CAN BELIEVE THIS GIVEN RADAR TRENDS/HISTORY
AND OBSERVED/FORECAST SURFACE FORCING. MORNING SOUNDING VERY
WET...WITH LITTLE TO NO CONVECTIVE INHIBITION. THUS...SCATTERED
CONVECTION (MORE NUMEROUS SOUTHERN COASTAL AREAS) SEEMS REASONABLE
THIS MORNING...WITH ACTIVITY PUSHING FARTHER WEST DURING THE
AFTERNOON ONCE ENOUGH DAYTIME HEATING GETS GOING TO GET A SEA-
BREEZE STARTED. OTHER ADJUSTMENTS TO FIRST AND SECOND PERIOD
GRIDS. PRODUCTS ARE OUT. MARINE FORECAST FOR NOW LOOKS REASONABLE.
&&
.PREV DISCUSSION... /ISSUED 643 AM CDT TUE SEP 10 2013/
DISCUSSION...UPDATED FOR THE 12Z AVIATION DISCUSSION.
AVIATION...GENERAL VFR CONDITIONS...WITH BRIEF MVFR CIGS/IFR
VSBYS IN AND AROUND SHOWERS/STORMS. RAIN COVERAGE IS EXPECTED TO
INCREASE...ESPECIALLY ACROSS THE COASTAL PLAINS FROM CRP-ALI-VCT
THROUGH THE LATE MRNG/EARLY AFTN. ISOLATED DEVELOPMENT IS EXPECTED
TO REACH LRD BY MID AFTN...THEREFORE WILL ONLY MAINTAIN VCTS IN
TAFS FOR NOW. THE TROPICAL AIRMASS WILL LEAD TO MOSTLY SHOWER
ACTIVITY...HOWEVER WITH ADDITIONAL HEATING AND WEAK UPPER LEVEL
SUPPORT...THUNDER REMAINS POSSIBLE DURING THE LATE MRNG/AFTN/EVNG
HOURS. ACTIVITY SHOULD WANE FROM EAST TO WEST THROUGH THE EVENING.
GENERAL EASTERLY WINDS 10-15 KTS ARE EXPECTED TO DEVELOP INTO THE
AFTERNOON BEFORE DECOUPLING THIS EVENING.
PREV DISCUSSION... /ISSUED 417 AM CDT TUE SEP 10 2013/
SHORT TERM (TODAY THROUGH WEDNESDAY)...ISOLATED SHOWERS DEVELOPING
ACROSS PORTIONS OF SOUTH TEXAS THIS MORNING DUE TO PWATS NEAR 2
AND SURFACE COASTAL TROUGH SOUTH OF THE AREA WITH WEAK PVA AT H5
ACROSS THE NORTHEASTERN CWA. ADDITIONAL COVERAGE IS EXPECTED TO
DEVELOP THROUGH THE LATE MORNING AND AFTERNOON...WITH HIGHER
CHANCE POPS MAINLY ACROSS THE EASTERN HALF OF THE CWA. AN UPPER
WEAK JET STREAK SHOULD PROVIDE A BIT MORE DIFFLUENT FLOW ACROSS
THE AREA...WHICH MAY LEAD TO A FEW STORMS BECOMING STRONG THIS
AFTERNOON...PARTICULARLY OVER THE COASTAL PLAINS. OTHERWISE...MOST
ACTIVITY SHOULD REMAIN AS SHOWERS WITH GENERAL THUNDER. DUE TO
DEEP TROPICAL MOISTURE...LOCALLY HEAVY RAINFALL CAN BE
EXPERIENCED. RAIN CHANCES WILL THEN TAPER OFF THROUGH THE EVENING
HOURS WITH THE LOSS OF HEATING. THE MID/UPPER LEVEL RIDGE ACROSS
THE EASTERN U.S. WILL SLOWLY SHIFT WESTWARD THROUGH WEDNESDAY WITH
DRIER AIR APPROACHING FROM THE NORTHEAST. HOWEVER PWATS NEAR 1.8
INCHES WILL REMAIN ACROSS THE SOUTH TEXAS...LEADING TO A SLIGHT
CHANCE TO LOW END CHANCE POPS FOR SHOWERS THROUGH WEDNESDAY. AS
FOR TEMPERATURES...HIGHS ARE DEPENDENT ON CLOUD AND RAIN
COVERAGE...HOWEVER WITH BETTER CHANCES FOR RAIN ACROSS THE COASTAL
BEND...WILL MAINTAIN TEMPS IN THE UPPER 80S...WITH LOWER 90S
FARTHER INLAND. SLIGHTLY WARMER TEMPERATURES ARE EXPECTED FOR
WEDNESDAY.
LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...MODELS CONTINUE TO
INDICATED MID LEVEL DRYING OCCURS FROM NORTHEAST TO SOUTHWEST
THURSDAY AND FRIDAY...AS THE MID AND UPPER LEVEL RIDGE ACROSS THE
SOUTHEAST U.S. BUILDS BACK TO THE WEST. PRECIPITABLE WATER VALUES
FALL TO 1.6-1.8 INCHES ON THURSDAY AND TO LESS THAN 1.5 INCHES ON
FRIDAY. EXPECT COVERAGE OF SHOWERS AND THUNDERSTORMS TO DECREASE
TO ISOLATED...WITH BEST CHANCES FOR PRECIP MAINLY ACROSS MARINE AND
SOUTHERN AREAS OF THE CWA.
ATTENTION SHIFTS TO THE BAY OF CAMPECHE DURING THE LATTER HALF OF
THE WEEK AND INTO THE WEEKEND. AN AREA OF DISTURBED WEATHER LOCATED
OVER THE NORTHWESTERN CARIBBEAN SEA IS MOVING WESTWARD AND IS
FORECAST TO MOVE ACROSS THE YUCATAN PENINSULA AND INTO THE BAY OF
CAMPECHE BY LATE THURSDAY. MODELS ARE INDICATING AN AREA OF BROAD
LOW PRESSURE TO FORM IN THE BAY OF CAMPECHE...AND NHC HAS
HIGHLIGHTED THIS REGION FOR A HIGH CHANCE OF TROPICAL CYCLONE
DEVELOPMENT DURING THIS TIME. GFS AND ECMWF INDICATE EITHER WAVE OR
CLOSED LOW MOVING WEST-NORTHWEST INTO VERACRUZ OR TAMAULIPAS MEXICO
SUNDAY OR MONDAY. HOWEVER...MODELS ARE INDICATING THE MID AND UPPER
LEVEL RIDGE ACROSS TO BUILD BACK INTO THE SOUTHEAST U.S. DURING THIS
TIME...ALLOWING DEEP SURGE OF TROPICAL MOISTURE NORTH OF THE
POTENTIAL SYSTEM TO POSSIBLY MAKE IT INTO SOUTH TEXAS. HAVE RAISED
POPS INTO THE HIGH END SCATTERED RANGE SUNDAY AND MONDAY AND LOWERED
FORECAST HIGHS. FURTHER FORECAST ADJUSTMENTS SUNDAY AND MONDAY ARE
LIKELY GIVEN THE UNCERTAINTY. FINALLY...AN INCREASE IN LONG PERIOD
SWELLS AND DEEP EASTERLY FETCH WILL LEAD TO AN INCREASE IN THE RIP
CURRENT THREAT ALONG THE BARRIER ISLANDS OVER THE WEEKEND AND INTO
EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 87 77 93 76 93 / 60 20 20 20 30
VICTORIA 91 74 93 74 94 / 50 20 20 10 20
LAREDO 95 75 96 76 95 / 30 20 30 20 30
ALICE 87 74 90 74 92 / 50 20 20 10 30
ROCKPORT 88 78 91 78 90 / 50 20 20 20 20
COTULLA 92 74 95 73 95 / 40 20 20 20 20
KINGSVILLE 87 75 92 75 93 / 50 20 30 20 30
NAVY CORPUS 87 77 90 78 89 / 60 20 20 20 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...SHORT TERM
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1216 PM EDT TUE SEP 10 2013
...MODERATE RISK FOR RIP CURRENTS ALONG THE BEACHES OF NORTH
COASTAL GEORGIA THROUGH THIS EVENING...
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND ACROSS THE AREA THROUGH THE MIDDLE OF
THE WEEK BEFORE A BACKDOOR COLD FRONT DROPS ACROSS THE AREA LATE
FRIDAY AND FRIDAY NIGHT. COOLER HIGH PRESSURE WILL THEN BUILD INTO
THE REGION FROM THE NORTH INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FOR THE REMAINDER OF
THE AFTERNOON HOURS. SHOWERS CONTINUE TO STREAM IN FROM OFF THE
ATLANTIC AND IMPACT PORTIONS OF COASTAL GEORGIA. INCREASED POPS TO
30 PERCENT AND NUDGED CLOUD COVER UP A BIT IN THIS AREA.
OTHERWISE...THE FORECAST IS ON TRACK.
A WELL DEFINED LAND BREEZE COUPLED WITH A NOTICEABLE WIND SURGE
WORKING DOWN THE SOUTH CAROLINA AND GEORGIA COASTS HAS PROMOTED
STRONG SURFACE MOISTURE FLUX CONVERGENCE IN EXCESS OF 20 G/KG/12HR
ACROSS THE COASTAL WATERS AND NORTH COASTAL GEORGIA THIS MORNING.
THIS HAS ALLOWED SOME SHOWER ACTIVITY TO DEVELOP AND MOVE ONSHORE
THIS MORNING. THE H3R AND RAP IDENTIFIED THIS ACTIVITY RATHER WELL
AND MAINTAIN A STREAM OF ISOLATED SHOWERS MOVING ONSHORE FOR MUCH
OF THE DAY...MAINLY FROM HILTON HEAD SOUTH INTO SOUTHEAST GEORGIA.
HAVE ADJUSTED POPS FOR THE LATE MORNING UPDATE TO MATCH GOING
NEAR TERM AND MODEL TRENDS...EXTENDING SLIGHT CHANCE POPS FROM THE
CHARLESTON COUNTY BEACHES INTO SOUTHEAST GEORGIA. SLIGHT CHANCE
POPS ARE ONLY SHOWN THROUGH EARLY AFTERNOON FOR CHARLESTON COUNTY
AND COASTAL COLLETON AS THE BEST SURFACE MOISTURE CONVERGENCE IS
EXPECTED TO REMAIN TO THE SOUTH...BUT THIS MAY NEED TO BE
READJUSTED LATER TODAY ONCE MESOSCALE TRENDS BECOME MORE APPARENT.
OTHERWISE...EXPECT DRY CONDITIONS INLAND TODAY WITH HIGHS RANGING
FROM THE LOWER 90S INLAND TO MID 80S AT THE BEACHES. IT WILL ALSO
BE RATHER BREEZY FROM ROUGHLY TYBEE ISLAND SOUTH TO SAPELO ISLAND
WITH WINDS 15-25 MPH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
TONIGHT...SURFACE HIGH PRESSURE WILL CONTINUE NORTH OF THE AREA
WHILE ANOTHER WEAK COASTAL TROUGH DEVELOPS AGAIN. SOME DEEPER
MOISTURE SHIFTING TOWARD THE COAST ON THE NORTH SIDE OF THE UPPER
LOW ALONG WITH THE SURFACE TROUGH SHOULD PRODUCE A BIT MORE IN THE
WAY OF SHOWERS AND POSSIBLY A FEW THUNDERSTORMS OVER THE ATLANTIC
WHICH WILL SHIFT TOWARD THE COAST LATE...MAINLY IN GEORGIA. LOWS
SHOULD REACH THE MID/UPPER 60S INLAND WITH MID 70S AROUND THE
COASTAL AREAS.
WEDNESDAY THROUGH FRIDAY...AN INVERTED UPPER LEVEL TROUGH WILL
RETROGRADE TOWARD THE SOUTHEAST U.S. COAST ON WEDNESDAY...CAUSING
THE EASTERN PERIPHERY OF THE UPPER LEVEL RIDGE OVER THE REGION TO
ERODE. THE INVERTED TROUGH WILL THEN BECOME ABSORBED INTO A LARGER
LONGWAVE TROUGH DIGGING INTO THE EASTERN U.S. ON THURSDAY AND
FRIDAY. MEANWHILE AT THE SURFACE...HIGH PRESSURE WILL BUILD INTO
THE REGION FROM THE NORTH ON WEDNESDAY...WITH ITS AXIS THEN
SHIFTING ACROSS THE AREA ON THURSDAY BEFORE IT BECOMES ESTABLISHED
OVER THE WESTERN ATLANTIC AHEAD OF A NEARING BACKDOOR COLD FRONT
ON FRIDAY.
STRONG SUBSIDENCE AND A LACK OF DEEP MOISTURE WILL PREVENT THE
FORMATION OF ANY CONVECTION INTO FRIDAY MORNING...ALTHOUGH SLIGHTLY
ENHANCED LOW LEVEL CONVERGENCE OFFSHORE COULD SUPPORT A FEW
SHOWERS/THUNDERSTORMS AT TIMES. TRAJECTORIES COULD ALLOW AN ISOLATED
SHOWER/THUNDERSTORM TO ADVECT INLAND ALONG PORTIONS OF THE IMMEDIATE
GEORGIA COAST...BUT OVERALL PROBABILITIES ARE LOW. MOISTURE SHOULD
INCREASE SUFFICIENTLY AHEAD OF THE APPROACHING BACKDOOR COLD FRONT
TO SUPPORT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS FRIDAY
AFTERNOON...WITH THE GREATEST COVERAGE ACROSS SOUTHEAST SOUTH
CAROLINA.
HIGH TEMPERATURES WILL REMAIN AROUND 90 INLAND FROM COOLER COASTAL
AREAS...WITH LOWS RANGING FROM THE MID 60S WELL INLAND TO THE LOWER
AND MID 70S NEAR THE IMMEDIATE COAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
MEDIUM RANGE GUIDANCE REMAINS IN VERY GOOD AGREEMENT FOR MOST OF THE
LONG TERM PERIOD. A LONGWAVE UPPER LEVEL TROUGH WILL PREVAIL OVER
THE EASTERN U.S. THROUGH SATURDAY...BEFORE LIFTING OUT TO THE
NORTHEAST AND ALLOWING A RIDGE AND/OR MORE ZONAL FLOW TO DEVELOP
ALOFT AND PREVAIL INTO EARLY NEXT WEEK. AT THE SURFACE...A BACKDOOR
COLD FRONT WILL DROP THROUGH THE AREA FRIDAY NIGHT...THEN BECOME
NEARLY STATIONARY SOMEWHERE ACROSS FAR SOUTHERN GEORGIA OR NORTHERN
FLORIDA INTO EARLY NEXT WEEK AS IT BECOMES ALIGNED WITH THE FLOW
ALOFT. BEHIND THE FRONT...HIGH PRESSURE WILL BUILD INTO THE REGION
FROM THE NORTH.
AS FOR EXPECTED WEATHER...THERE IS A CHANCE FOR SHOWERS AND
THUNDERSTORMS TO ACCOMPANY THE PASSAGE OF THE FRONT FRIDAY NIGHT
WITH LINGERING MOISTURE BEHIND THE FRONT KEEPING EITHER A SLIGHT
CHANCE OR CHANCE OF SHOWERS IN THE FORECAST FOR SATURDAY. THE
PROXIMITY OF THE FRONT AND LOW LEVEL TRAJECTORIES WILL FAVOR KEEPING
A SLIGHT CHANCE OF PRECIPITATION IN THE FORECAST INTO EARLY NEXT
WEEK FOR PORTIONS OF SOUTHEAST GEORGIA AND FAR SOUTHERN SOUTH
CAROLINA...BUT ESPECIALLY ALONG THE SOUTHEAST GEORGIA COAST.
SIGNIFICANTLY COOLER TEMPERATURES WILL OCCUR FOLLOWING THE PASSAGE
OF THE BACKDOOR COLD FRONT...WITH A NORTHEAST FLOW ONLY SUPPORTING
HIGHS IN THE LOWER TO MID 80S OVER THE WEEKEND. TEMPERATURES WILL
THEN BEGIN TO MODERATE EARLY NEXT WEEK.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
VFR. ISOLATED SHOWER ACTIVITY COULD IMPACT KSAV AT JUST ABOUT ANY
TIME THROUGH SUNRISE WEDNESDAY. HOWEVER...MOST ACTIVITY IS
EXPECTED TO REMAIN SOUTH AND EAST OF THE TERMINAL. SHOULD RAIN
OCCUR...IT WOULD BE FAIRLY BRIEF WITH ONLY VERY LIMITED
IMPACTS...IF ANY. WILL NOT INCLUDE A MENTION ATTM GIVEN THE
LIMITED IMPACTS.
EXTENDED AVIATION OUTLOOK...THERE ARE NO CONCERNS WITH A GREATER
THAN 30 PERCENT CONFIDENCE.
&&
.MARINE...
TODAY...MODEST WIND SURGE IS ONGOING ACROSS THE WATERS THIS
MORNING WITH SPEEDS ROUGHLY 15-20 KT...EXCEPT 15 KT OFF THE
CHARLESTON COUNTY COAST. RAP/H3R SHOW 15-20 KT WINDS HOLDING FOR
MUCH OF THE DAY. SEAS WILL BUILD SLIGHTLY...3-4 FT MOST ZONES.
TONIGHT...HIGH PRESSURE WILL REMAIN NORTH OF THE AREA WITH MOSTLY
EAST WINDS 15 KNOTS OR LESS AND SEAS UP TO 3 FT WITHIN 20 NM AND
UP TO 4 FT IN THE 20-60 NM GEORGIA ZONE.
WEDNESDAY THROUGH SUNDAY...HIGH PRESSURE WILL PERSIST OVER THE
WATERS THROUGH WEDNESDAY NIGHT...MAINTAINING QUIET CONDITIONS. THE
FLOW WILL BECOME MORE SOUTHERLY THURSDAY AND FRIDAY AHEAD OF AN
APPROACHING COLD FRONT...WHICH IS EXPECTED TO DROP ACROSS THE WATERS
LATE FRIDAY AND FRIDAY NIGHT. A STRONG NORTHEAST SURGE WILL THEN
OCCUR IN WAKE OF THE FRONT SATURDAY AND SUNDAY...LIKELY RESULTING IN
SMALL CRAFT ADVISORY CONDITIONS OVER MOST OF THE WATERS. SEAS WILL
GENERALLY BE NO HIGHER THAN 2-4 FT...GREATEST OVER THE OUTER GEORGIA
WATERS...THROUGH FRIDAY BEFORE INCREASING A COUPLE OF FEET OVER THE
WEEKEND AS THE STRONG NORTHEAST FLOW DEVELOPS AND THE FETCH
INCREASES.
RIP CURRENTS...WINDS ARE BEEN AVERAGING 15-20 MPH ALONG THE
GEORGIA BEACHES THIS MORNING WITH OCCASIONAL HIGHER GUSTS. RAP/H3R
KEEP BREEZY CONDITIONS IN PLACE AS ISOLATED SHOWERS MOVE INLAND
THROUGHOUT THE DAY. THIS COUPLED WITH 3 FOOT SEAS AND PERIODS
AROUND 8 SECONDS WILL SUPPORT A LOW-END MODERATE RISK FOR RIP
CURRENTS THROUGH EARLY THIS EVENING. WILL MAINTAIN A LOW RISK FOR
THE SOUTH CAROLINA BEACHES GIVEN THE SLIGHTLY LOWER WIND SPEEDS
THAT ARE EXPECTED...BUT THIS WILL BE MONITORED THROUGHOUT THE DAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
409 PM EDT TUE SEP 10 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 408 PM EDT TUE SEP 10 2013
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...A SHORTWAVE MOVING ACROSS
NRN ONTARIO AND LAKE SUPERIOR THIS AFTERNOON COMBINED WITH UPR DIV
IN RIGHT ENTRANCE REGION OF ASSOC 100+ KT 3H JET HAVE HELPED SUSTAIN
A COUPLE DIFFERENT BATCHES OF SHRA WHICH HAVE MOVED OVER THE WEST
HALF OF UPPER MI THIS AFTERNOON. UPSLOPE FOG WHICH PLAGUED THE
KEWEENAW INTO THE EARLY AFTERNOON HOURS LOOKS LIKE IT HAS FINALLY
LIFTED PER SFC OBS AND WEB CAMS BUT STRATUS CLOUDS STILL REMAIN. AT
THE SFC...A COUPLE OF SFC TROUGHS EXTEND FM LOW PRES CENTERED NE OF
LAKE SUPERIOR...ONE TROUGH EXTENDS INTO ERN AND SCNTRL UPR MI WHILE
ANOTHER IS STILL SITUATED OVER FAR NRN LAKE SUPERIOR AND ONTARIO.
TONIGHT...EXPECT AREA OF SHOWERS NOW EXTENDING FM IRON COUNTY INTO
WRN MQT COUNTY TO MOVE SLOWLY EAST OVER THE NEXT COUPLE OF HOURS AND
THEN GRADUALLY DISSIPATE THIS EVENING AS 700-650 MB FGEN SLOWLY
WEAKENS. THERE IS A CONCERN THAT A STRONG TO POSSIBLY SVR STORM
COULD FORM OVER THE ERN HALF OF UPPER MI IN THE NEXT FEW HOURS.
PARTIAL SUNSHINE HAS ALLOWED MLCAPES TO BUILD UP TO AROUND 2000
J/KG. THIS ALONG WITH EFFECTIVE SHEAR OF 50-60 KT AND ENHANCED
CONVERGENCE ALONG SFC TROUGH COULD TRIGGER STORMS OVER ERN UPPER MI
LATE AFTERNOON INTO EARLY EVENING. THIS WILL NEED TO BE CLOSELY
MONITORED ON THE EVENING SHIFT.
THE OTHER CONCERN TONIGHT IS THE POTENTIAL FOR MORE FOG TO FORM LATE
EVENING INTO OVERNIGHT HRS AS TEMPS RADIATE THROUGH UPPER 50S/LOWER
60S DEWPOINTS UNDER LIGHT WINDS AND PARTIAL CLEARING. HAVE EXPANDED
MENTION OF PATCHY TO AREAS OF FOG ACROSS THE CWA AND WOULD NOT BE
SURPRISED TO SEE SOME LOCALLY DENSE FOG AT SOME LOCATIONS.
WEDNESDAY...ANOTHER SHORTWAVE NOW DROPPING DOWN FROM NRN
SASKATCHEWAN/NRN MANITOBA WILL HELP PUSH FRONTAL BOUNDARY INTO THE
AREA. SCNTRL AND ERN UPR MI WILL AGAIN HAVE BEST CHC OF AFTERNOON
SHRA/TSRA AS MLCAPES ARE FCST BY MODELS TO INCREASE TO 500-1000
J/KG. WILL INCLUDE HIGHER CHC 40 PCT POPS OVER THIS AREA. WITH WEAK
DOWNSLOPE WRLY FLOW INTO THE BAY OF GREEN BAY...EXPECT THE WARMEST
HIGH TEMPS (LOWER TO MID 80S) OVER MNM COUNTY. ELSEWHERE MAX TEMPS
WILL GENERALLY BE IN THE 70S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 408 PM EDT TUE SEP 10 2013
COLD FRONT WILL BE DEPARTING THE CWA AT THE START OF THE LONG TERM
PERIOD...WHILE A POTENT SHORTWAVE DROPS SOUTHEAST ACROSS THE UPPER
GREAT LAKES REGION. THE MAIN PRECIPITATION WITH THE COLD
FRONT WILL BE SLIDING SOUTHEAST OVER THE EASTERN CWA TO START THE
PERIOD. BEHIND THIS...THERE SHOULD BE A QUICK BREAK TO THE
PRECIPITATION BEFORE COLDER AIR AND ABUNDANT LOW LEVEL MOISTURE
SURGES SOUTH ACROSS LAKE SUPERIOR LATE WEDNESDAY NIGHT INTO THURSDAY
ON THE EAST SIDE OF THE HIGH MOVING INTO THE NORTHERN PLAINS.
THUS...WOULD EXPECT A PERIOD OF PARTLY CLOUDY SKIES FOR A TIME
WEDNESDAY NIGHT BEFORE THE 850MB TEMPS FALL TO 0C BETWEEN 18Z
THURSDAY TO 00Z FRIDAY. SINCE LAKE SUPERIOR TEMPS ARE AROUND
12-16C...THIS INCREASING COLD AIR WILL PUSH DELTA T VALUES TOWARDS
FAVORABLE LAKE EFFECT RAIN SHOWERS AND CLOUDS. THE INVERSION HEIGHT
IS RIGHT AROUND 825MB OR 4.5KFT...SO THAT WILL LIMIT THE CLOUD DEPTH
FOR STRONGER SHOWERS...BUT STILL THINK THERE WILL BE ENOUGH AROUND
FOR ISOLATED/SCATTERED MENTION IN THE FAVORED NORTH-NORTHWEST WIND
LOCATIONS. WILL RAMP UP THE POPS THROUGH THE DAY AS THE COLDEST AIR
AND BEST MOISTURE ARRIVES IN THE AFTERNOON AND EARLY EVENING.
IT IS STARTING TO LOOK LIKE THE CLOUDS WILL LINGER LONGER ON
THURSDAY NIGHT...WHICH BRINGS THE LOW FORECAST AND FROST
POTENTIAL INTO QUESTION. OPTED TO TREND TEMPS AND CLOUDS UP SOME
THROUGH THE NIGHT. THE BEST OPPORTUNITY FOR BREAKS IN THE CLOUDS
LOOKS TO BE OVER THE VERY FAR WEST (GOGEBIC/ONTONAGON COUNTIES) AND
WILL KEEP THE COLDEST TEMPERATURES THERE. THIS LONGER LASTING
MOISTURE CALLS FOR THE CLOUDS TO HANG ON INTO AT LEAST FRIDAY
MORNING AND HAVE TRENDED THE SKY FORECAST UP SIGNIFICANTLY FOR THAT
TIME. ALSO DELAYED THE END OF THE SHOWER CHANCES INTO THE MORNING
FOR LOCATIONS FROM MARQUETTE EASTWARD. ALL OF THE MODELS ARE SHOWING
THE MOISTURE DIMINISHING FROM WEST TO EAST DURING THE AFTERNOON AS
THE HIGH MOVES OVER THE CWA. HIGHS ON FRIDAY WILL BE FAIRLY
COOL...WITH HIGHS IN THE MID AND UPPER 50S.
THIS HIGH WILL LEAD TO A VERY CHILLY NIGHT ON FRIDAY NIGHT. SINCE
WINDS WILL BECOME CALM...SKIES WILL BE CLEAR...AND PWATS ARE AROUND
40-45 PERCENT OF NORMAL...EXPECT A GOOD RADIATIONAL COOLING NIGHT.
FORECAST HAS BEEN HITTING THE POTENTIAL FOR FROST ON FRIDAY NIGHT
AND THAT CONTINUES TO SEEM REASONABLE. DID TREND LOWS DOWN A COUPLE
DEGREES OVER THE INTERIOR LOCATIONS AND IT APPEARS LIKE THERE WILL
BE A DECENT OPPORTUNITY FOR FROST IN THAT AREA WITH LOWS IN THE MID
30S. SOME OF THE TRADITIONAL COLD SPOTS OVER THE CENTRAL/EAST MAY
EVEN FALL BELOW FREEZING FOR AWHILE.
THE HIGH WILL SHIFT SOUTHEAST ON SATURDAY AND INCREASING SOUTHERLY
FLOW WILL PUSH TEMPERATURES BACK TOWARDS NORMAL AND AROUND . WITH
10 DEGREES WARMER THAN FRIDAY. THE AREA UNDER A RIDGE ALOFT...EXPECT
A MOSTLY SUNNY DAY ON SATURDAY.
THE NEXT SHORTWAVE AND ASSOCIATED COLD FRONT WILL MOVE ACROSS THE
AREA SATURDAY NIGHT INTO SUNDAY MORNING. THE 12Z MODEL RUNS OF
THE ECMWF/GFS/GEM HAVE COME INTO DECENT AGREEMENT WITH THE
TRACK OF THE SHORTWAVE BRUSHING THE UPPER GREAT LAKES REGION
AND THUS THE TIMING/LOCATION OF THE FRONT AND PRECIPITATION.
SINCE THE MAIN FORCING/MOISTURE LOOKS TO TRACK ACROSS
NORTHEAST LAKE SUPERIOR...HAVE TRENDED POPS DOWN SOMEWHAT AND
TOWARDS SLIGHT CHANCE AND LOW CHANCE POPS. COLD AIR
WILL ONLY BRUSH THE AREA BEHIND THIS FRONT...SO THINK THE POTENTIAL
FOR LAKE ENHANCED CLOUDS/SHOWERS FOR SUNDAY NIGHT INTO MONDAY LOOKS
TO BE LESS LIKELY THAN SHOWN ON YESTERDAY/S RUNS. HIGH PRESSURE
BUILDS IN FOR MONDAY AND MONDAY NIGHT AND SHOULD LEAD TO DRY WEATHER
FOR THE START OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 320 PM EDT TUE SEP 10 2013
IFR CONDITIONS AT KCMX IN FOG/STRATUS WILL GRADUALLY LIFT TO MVFR
LATER THIS AFTERNOON WITH INCREASING WESTERLY FLOW AND DAYTIME
HEATING...ALTHOUGH UPSLOPE FLOW WILL LIMIT IMPROVEMENT. KIWD/KSAW
HAVE ALREADY IMPROVED TO VFR THIS AFTN. BAND OF SHRA OVER WRN UPR
MI/N CNTRL WI MAY HOLD TOGETHER TO GIVE KSAW SOME SHRA LATER THIS
AFTERNOON. VFR CONDITIONS SHOULD CONTINUE INTO EARLY EVENING AT KIWD
AND KSAW...BUT EXPECT MORE FOG REDEVELOPING BY LATE EVENING/OVERNIGHT
UNDER LIGHT WINDS AND PARTIAL CLEARING WITH LIFR TO VLIFR EXPECTED AT
ALL SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 408 PM EDT TUE SEP 10 2013
PATCHY TO AREAS OF FOG SHOULD SLOWLY DISSIPATE INTO THIS EVENING AS
DRIER AIR WORKS IN FROM THE NORTH. WEAK HIGH PRESSURE THIS EVENING
WILL BE REPLACED BY A BROAD TROUGH THAT WILL BE EXTENDING SOUTHWARD
FROM NORTHERN ONTARIO LATE TONIGHT THROUGH EARLY WEDNESDAY EVENING.
A LARGE HIGH PRESSURE ENCOMPASSING MUCH OF S CENTRAL CANADA AND THE
N PLAINS WEDNESDAY NIGHT WILL SLOWLY DRIFT ACROSS THE UPPER GREAT
LAKES FRIDAY INTO SATURDAY...BEFORE EXITING TO THE LOWER GREAT LAKES
AND THE E COAST FOR THE LATTER HALF OF THE WEEKEND. THE STRONGEST
WINDS OVER LAKE SUPERIOR...OUTSIDE OF THUNDERSTORMS...WILL BE LATE
WEDNESDAY NIGHT THROUGH EARLY FRIDAY MORNING...WITH N GUSTS OF
20-30KTS CENTERED ACROSS MAINLY CENTRAL AND E LAKE SUPERIOR.
&&
.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
327 PM EDT TUE SEP 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 527 AM EDT TUE SEP 10 2013
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...THE MID LEVEL LOW THAT
WAS OVER THE PACIFIC NW FOR SEVERAL DAYS IS NOW AN OPEN WAVE OVER
THE DAKOTAS INTO SRN MANITOBA. AT THE SFC...A LOW PRES TROF EXTENDS
FROM NW MN ACROSS LAKE SUPERIOR.
INITIALLY...WILL HAVE TO DEAL WITH SOME FOG EARLY THIS MORNING WHICH
WILL BE LOCALLY DENSE. WITH WESTERLY WINDS S OF THE SFC TROF
INCREASING A BIT OVER THE NEXT FEW HRS...FOG SHOULD CLEAR OUT OF THE
AREAS THAT SEE DOWNSLOPING WITH A W WIND. WHERE WINDS UPSLOPE...FOG
WILL DISSIPATE BY LATE MORNING UNDER A COMBINATION OF DAYTIME
HEATING AND MECHANICAL MIXING WITH INCREASING LOW-LEVEL WINDS. AS OF
09Z...KMQT RADAR DOES NOT SHOW ANY PCPN ACROSS THE FCST AREA.
HOWEVER...RIGHT ENTRANCE OF WSW TO ENE ORIENTED UPPER JET ASSOCIATED
WITH DAKOTAS/MANITOBA SHORTWAVE IS SUPPORTING A BKN BAND OF SHRA
FROM THE NEBRASKA TO NE MN. SOME OF THESE SHRA AND PERHAPS A TSRA
MAY AFFECT MAINLY WRN UPPER MI THIS MORNING AS UPPER JET TRANSLATES
EASTWARD. THIS AFTN...ATTENTION TURNS TO THE ERN FCST AREA AS
DAYTIME HEATING/LOW-LEVEL MOISTURE LEAD TO MLCAPE INCREASING TO
500-1000J/KG. WESTERLY LOW-LEVEL WINDS WILL LEAD TO ENHANCED
CONVERGENCE ACROSS INTERIOR ERN UPPER MI AS WINDS VEER NEAR LAKE
SUPERIOR AND BACK NEAR LAKE MICHIGAN AS LAKE BREEZE COMPONENT
DEVELOPS. EXPECT SCT SHRA/TSRA TO DEVELOP ROUGHLY ALONG A LINE
MIDWAY BTWN ESCANABA/MUNISING E TO NEWBERRY. ISOLATED SHRA/TSRA MAY
DEVELOP AS FAR W AS TOWARD KSAW/KIMT. AS FOR TEMPS...WITH INCREASING
W WINDS...DOWNSLOPE AREAS WILL SEE LOW CLOUDS CLEAR OUT THIS
MORNING. THIS WILL LIKELY LEAD TO A HOT/HUMID DAY OVER SCNTRL UPPER
MI AS DOWNSLOPING ENHANCES THE ALREADY VERY WARM START TO THE DAY.
MIXING TO 850-800MB ON NAM/GFS FCST SOUNDINGS SUGGESTS POTENTIAL FOR
MAX TEMPS INTO THE LOW/MID 90S OVER THE SCNTRL. SOME CLOUD COVER
THIS AFTN MAY LIMIT MIXING DEPTH...BUT DOWNSLOPING COULD STILL
SUPPORT TEMPS OVER 90F. FOR NOW...RAISED MAX TEMPS TO THE UPPER 80S
OVER THE SCNTRL WITH LOWER 80S EXTENDING INTO THE INTERIOR ERN FCST
AREA. ELSEWHERE...70S SHOULD BE THE RULE...THOUGH TEMPS MAY TOP 80F
WHERE W WINDS DOWNSLOPE.
AS UPPER JET CONTINUES TO TRANSLATE EASTWARD TONIGHT...RIGHT
ENTRANCE OF JET WILL AID A RIBBON OF LOW-MIDLEVEL FRONTOGENESIS
ACROSS THE UPPER LAKES. CONSENSUS OF MODEL GUIDANCE SHOWS THIS
FORCING SUPPORTING A BAND OF SHRA STREAKING ENE ACROSS WI TOWARD THE
STRAITS. THERE IS SOME UNCERTAINTY IN EXACTLY WHERE THIS RELATIVELY
NARROW BAND OF PCPN WILL BE LOCATED...BUT BULK OF GUIDANCE SUGGESTS
THE FAR SCNTRL/SE FCST AREA WILL BE CLIPPED. OPTED TO INCLUDE LOW
CHC POPS IN THAT AREA. SOME OF THE HIGHER RESOLUTION MODEL GUIDANCE
ALSO INDICATE LATE AFTN SHRA OVER NRN MN MAKING IT ACROSS LAKE
SUPERIOR AND AFFECTING WRN UPPER MI THIS EVENING. INCLUDED SCHC POPS
OVER THE W THIS EVENING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 525 AM EDT TUE SEP 10 2013
OUR ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH THURSDAY. WE WILL
FINALLY DISPLACE THE 500MB TROUGH THAT HAS BEEN BEEN SET UP ACROSS
THE NORTHERN TIER OF CENTRAL AND EASTERN U.S. FRIDAY NIGHT THROUGH
THE START OF THE UPCOMING WEEKEND...AS THE RIDGE MOVES OVERHEAD.
STARTING OUT AT 12Z WEDNESDAY...THE SFC LOW OVER N ONTARIO WILL BE
DRAGGING A COLD FRONT ACROSS MN AND FAR W LAKE SUPERIOR. MAINLY
AFTERNOON CONVECTION IS EXPECTED AS THE COLD FRONT DRAGS ACROSS THE
AREA...WITH THE ASSIST OF DAYTIME HEATING. ML CAPE VALUES TO OUT
AROUND 500J/KG OR LESS WEDNESDAY AFTERNOON OVER THE E HALF TO
TWO-THIRDS OF UPPER MI...AND QUICKLY DIMINISH TOWARD 00Z.
LARGE HIGH PRESSURE OVER S CENTRAL CANADA AND THE N PLAINS WEDNESDAY
NIGHT/THURSDAY MORNING WILL THEN BE THE MAIN INFLUENCE ON OUR
WEATHER FOR THE END OF THE WEEK. STRONG N WINDS /SLOWED DOWN APPROX
3-6HRS/ STILL LOOK REASONABLE...USHERING IN COLD AIR ACROSS LAKE
SUPERIOR AND UPPER MI.
THE COLDEST AIR OVERHEAD LOOKS TO BE SET UP AROUND 06Z FRIDAY...WITH
850MB TEMPS FALLING TO 1 TO -4C /COOLEST OFF THE ECMWF/. WHILE THERE
REMAINS THE POTENTIAL FOR FROST DEVELOPMENT...WITH THE COLD AIR
OVERHEAD AND PW VALUES FALLING TO AROUND 45 PERCENT OF NORMAL
/0.3-0.4IN/...N-NNE WINDS OFF LAKE SUPERIOR MAY STILL BE BRINGING
LOW CLOUDS AND EVEN LAKE ENHANCED RAIN SHOWERS/DRIZZLE ON N-NNE
WINDS OFF LAKE SUPERIOR.
AS FOR THE FROST POTENTIAL FOR FRIDAY NIGHT INTO SATURDAY
MORNING...WITH THE SFC HIGH SLIDING TO S CENTRAL AND EASTERN UPPER
MI...THE LIGHTEST WINDS WILL BE THERE. PW VALUES WILL NOT BE QUITE
AS LOW...IN THE 0.4-0.5 RANGE OR AROUND 50 PERCENT OF NORMAL. THESE
SLIGHTLY HIGHER PW VALUES AND 850MB TEMPS AROUND 5C WILL BE OFFSET
BY THE LIGHTER WINDS AND CLEAR SKY...WITH SIMILAR TEMP READINGS
EXPECTED ACROSS CENTRAL AREAS.
LOOK FOR A TEMPORARILY BREAK TO THE COOL WEATHER ON SATURDAY AND TO
A LESSER EXTENT SUNDAY...AS HIGHS TOP OUT IN THE 60S. THIS IS STILL
4-10F BELOW NORMAL FOR THIS TIME OF YEAR. WAA ON WSW WINDS SATURDAY
SHOULD ALLOW 850MB TEMPS TO RISE TO 8-10C. SUNDAY WILL BE A
DIFFERENT STORY...AS A SHORTWAVE LOOKS TO PUT AN END TO OUR DRY
WEATHER ON SUNDAY. SLOWED DOWN OUR INITIAL BLEND FOR THE EXTENDED
PERIOD...BUT LOOKING AT THE LATEST 10/00Z GFS/ECMWF RUNS. IN
FACT...THE SCATTERED POPS FOR SATURDAY NIGHT THROUGH SUNDAY LOOK TO
BE IN JEOPARDY IF THE 10/00Z GFS IS CORRECT...AS IT KEEPS US DRY
THROUGH AT LEAST NEXT MONDAY. WILL WAIT TO SEE HOW THE NEXT COUPLE
RUNS PLAY UP THIS FEATURE BEFORE MAKING TOO MANY CHANGES TO THE
ONGOING FCST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 320 PM EDT TUE SEP 10 2013
IFR CONDITIONS AT KCMX IN FOG/STRATUS WILL GRADUALLY LIFT TO MVFR
LATER THIS AFTERNOON WITH INCREASING WESTERLY FLOW AND DAYTIME
HEATING...ALTHOUGH UPSLOPE FLOW WILL LIMIT IMPROVEMENT. KIWD/KSAW
HAVE ALREADY IMPROVED TO VFR THIS AFTN. BAND OF SHRA OVER WRN UPR
MI/N CNTRL WI MAY HOLD TOGETHER TO GIVE KSAW SOME SHRA LATER THIS
AFTERNOON. VFR CONDITIONS SHOULD CONTINUE INTO EARLY EVENING AT KIWD
AND KSAW...BUT EXPECT MORE FOG REDEVELOPING BY LATE EVENING/OVERNIGHT
UNDER LIGHT WINDS AND PARTIAL CLEARING WITH LIFR TO VLIFR EXPECTED AT
ALL SITES. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 318 AM EDT TUE SEP 10 2013
PATCHY TO AREAS OF FOG SHOULD SLOWLY DISSIPATE THIS MORNING. LOW
PRESSURE EXITING E LAKE SUPERIOR TODAY WILL BE REPLACED BY A BROAD
TROUGH THAT WILL BE EXTENDING SOUTHWARD FROM NORTHERN ONTARIO LATE
TONIGHT THROUGH EARLY WEDNESDAY EVENING. A LARGE HIGH PRESSURE
ENCOMPASSING MUCH OF S CENTRAL CANADA AND THE N PLAINS WEDNESDAY
NIGHT WILL SLOWLY DRIFT ACROSS THE UPPER GREAT LAKES FRIDAY INTO
SATURDAY...BEFORE EXITING TO THE LOWER GREAT LAKES AND THE E COAST
FOR THE LATTER HALF OF THE WEEKEND. THE STRONGEST WINDS OVER LAKE
SUPERIOR...OUTSIDE OF THUNDERSTORMS...WILL BE THURSDAY MORNING
THROUGH EARLY FRIDAY MORNING...WITH NW GUSTS OF 20-30KTS CENTERED
ACROSS MAINLY CENTRAL AND E LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...VOSS
MARINE...KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1221 PM CDT TUE SEP 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT TUE SEP 10 2013
A RATHER CONVOLUTED SURFACE/UPPER AIR PATTERN OVER THE REGION THIS
MORNING. CENTERS OF LOW PRESSURE WERE NOTED OVER NORTHERN WI...
NORTHERN MN AND ND. A LEAD COLD FRONT MEANDERED FROM NORTHERN WI
THROUGH SE MN AND EASTERN NE WHILE A SECONDARY COLD FRONT CURVED
ACROSS THE DAKOTAS. A THIRD AND REAL COLD FRONT WAS ACROSS SOUTH
CENTRAL CANADA... WHICH THE LONG TERM WILL DISCUSS BELOW. UPSTAIRS...
SUBTROPICAL MOISTURE WAS FLOWING NORTHEAST ACROSS THE CWA FROM THE
DESERT SOUTHWEST. A WAVE IN THE SUBTROPICAL FEED WAS NOTED OVER
WESTERN NE. THIS FEATURE IS PROGGED OVER SE MN BY THIS EVENING. A
LITTLE FURTHER NORTHWEST... A TROUGH IN THE POLAR JET WAS NEARING
THE ND/MN BORDER. THE DAY AHEAD WILL FEATURE INCREASING MID LEVEL
FRONTOGENESIS SPREADING NORTHEAST FROM SD/NE... THE INTERACTION
BETWEEN THE TWO WAVES ALOFT. SOME SHOWERS AND ISOLATED
THUNDERSTORMS HAVE ALREADY SPREAD INTO SOUTHWEST AND WEST CENTRAL
MN EARLY THIS MORNING. ALTHOUGH THE ACTIVITY IS MOVING NE A SLIGHT
NORTHWARD DRIFT IS SEEN IN THE OVERALL PATTERN. VARIOUS MODEL
SOLUTIONS SHOW PLENTY OF LAYER RH ALONG WITH THE MID LEVEL
FRONTOGENESIS. HOWEVER...LITTLE TO NO QPF IS PRODUCED WHICH DOES
NOT SEEM RIGHT WHEN LOOKING AT THE ADIABATIC OMEGA AND
SATURATION ON THE 305/310K THETA SURFACES. THE NAM PRODUCES THE
MOST QPF BUT APPEARS TO BE TOO FAR SOUTH INITIALLY. THE PAST FEW
RUNS OF THE HRRR MATCH WELL WITH THE TRENDS AND WOULD SUGGEST THAT
THE SHOWERS AND ISOLATED THUNDERSTORMS OVER WEST CENTRAL MN WILL
MOVE NORTHEAST THIS MORNING WITH A PERIOD OF DRYING IN THEIR WAKE.
THEN...MORE SHOWERS DEVELOP THIS AFTERNOON ACROSS SOUTHERN MN AND
ADJOINING AREAS OF WEST CENTRAL WI AS THE WAVE FROM NE ARRIVES AND
THE MID LEVEL FRONTOGENESIS BEGINS SLIPPING SOUTH. THE SHOWERS
SHOULD THEN END THIS EVENING OVER FAR EASTERN AND SOUTHERN AREAS
FOLLOWED BY DECREASING CLOUDINESS. HIGHS TODAY WILL BE TIED TO THE
CLOUDS AND SHOWERS. THE WARMEST AREAS WILL STRETCH FROM SOUTH
CENTRAL MN THROUGH KEAU WHERE MIDDLE 80S ARE LIKELY. TO THE NORTH
AND WEST... MIDDLE 70S TO LOWER 80S ARE FORECAST. IT WILL STILL BE
MILD TONIGHT WITH LOWS IN THE UPPER 50S TO MIDDLE 60S BUT THAT
WILL CERTAINLY BE CHANGING FOR WEDNESDAY AND THURSDAY MORNINGS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 345 AM CDT TUE SEP 10 2013
MODEL AGREEMENT ON THE EVOLUTION OF THE UPPER AIR PATTERN IS HIGH
THROUGH THE COURSE OF THE WORK WEEK...BUT BEGIN TO DIVERGE
SIGNIFICANTLY OVER THE WEEKEND. DURING THE WEEK...WE WILL SEE A
RE-AMPLIFICATION OF WHAT HAS BECOME THE ALL TOO FAMILIAR H5 PATTERN
SINCE MID JULY OF A WRN NOAM RIDGE AND ERN NOAM THROUGH...WITH NW
FLOW FOR US STUCK IN THE MIDDLE. WITHIN THE RIDGE...A MONSOONAL WAVE
CURRENTLY OVER THE FOUR CORNERS WILL SLOWLY DRIFT NE INTO THE NRN
PLAINS THIS WEEKEND. FROM THERE...TWO DIFFERENT STORIES APPEAR. THE
PROTAGONIST IN BOTH OF THESE STORIES IS A NRN STREAM WAVE THAT WILL
BE WORKING ACROSS THE TOP OF THE RIDGE OVER SRN CANADA THIS WEEKEND.
THE 10.00 ECMWF...10.00 GEM...AND 09.12 GFS DIG THIS NRN WAVE FAR
ENOUGH SOUTH TO PICK UP THE MONSOONAL DISTURBANCE...AND DRIVE A
FAIRLY POTENT POSITIVELY TILTED TROUGH THROUGH THE GREAT
LAKES/UPPER MS VALLEY SAT NIGHT. THE 10.00 GFS AND 09.12 ECMWF
KEEP THIS NRN STREAM WAVE FAR ENOUGH NORTH THAT THE MONSOONAL WAVE
IS LEFT TO WANDER OVER THE NRN PLAINS WITHIN THE RIDGE FOR THE
WEEKEND INTO NEXT WEEK. AS YOU CAN IMAGINE...WITH THE ECMWF/GFS
SWAPPING THEIR POSITIONS BETWEEN THE 09.12 AND 10.00
RUNS...CONFIDENCE IN THE FORECAST BEGINS TO DECREASE CONSIDERABLY
THIS WEEKEND.
AT THE SFC...WEDNESDAY WILL FEATURE THE PASSAGE OF A SECONDARY COLD
FRONT...THAT WILL GIVE WAY TO COOL/DRY HIGH PRESSURE FOR THU/FRI.
RETURN FLOW SETS UP FOR SATURDAY...WITH RAIN CHANCES RETURNING AS A
RESULT. THE CURRENT RUN OF THE ECMWF /OLD GFS/ DRIVE ANOTHER FRONT
THROUGH SAT NIGHT/SUNDAY...WHILE THE OLD ECMWF /NEW GFS/ KEEP A
MOIST SRLY FETCH GOING THROUGH THE WEEKEND AND INTO NEXT AS THE
MONSOONAL WAVE SITS AND SPINS OVER THE NRN PLAINS.
FOR TEMPERATURES...WEDNESDAY WILL BE THE WARMEST DAY...AS 925-850 MB
TEMPS CONTINUE TO RUN BETWEEN 16C AND 20C. A MAINLY SUNNY DAY IS
EXPECTED IN THE WAKE OF ALL OF TODAY/TONIGHTS WAVINESS...AND MIXING
THESE TEMPS DOWN SUPPORTS HIGHS IN THE LOW/MID 80S. THE SECONDARY
COLD FRONT CLEARING THE AREA WEDNESDAY NIGHT WILL SEND 925-850 MB
TEMPS BACK INTO THE SINGLE DIGITS...WHICH WILL BRING BACK
TEMPERATURES SLIGHTLY BELOW NORMAL TO END THE WEEK. IN ADDITION...
ON FRIDAY MORNING...HIGH PRESSURE WILL BE OVER/AROUND WRN LAKE
SUPERIOR AND THE COMBO OF CLEAR SKIES AND CALM WILL GIVE US OUR
FIRST SHOT AT SEEING SOME FROST /WITH LOWS INTO THE MID 30S/ ACROSS
RUSK/BARRON/DUNN/CHIPPEWA COUNTIES IN WI. BY THE WEEKEND...
TEMPS/THICKNESSES WILL INCREASE...BUT THE RETURN OF CLOUD COVER WILL
HELP HOLD HIGHS BACK AROUND NORMAL...WHICH ARE ALREADY DOWN INTO THE
LOW/MID 70S.
AS FOR PRECIP...MODELS HAVE BEEN TRENDING SLOWER WITH ITS RETURN
OVER THE WEEKEND...SO SLOWED THE EASTWARD ADVANCEMENT OF POPS ACROSS
THE AREA ON SATURDAY AS A RESULT. THE HIGHER POPS IN THE FORECAST
SAT NIGHT INTO SUNDAY WOULD FAVOR THE 10.00 ECMWF SOLUTION...BUT THE
IMPACT OF THE 10.00 GFS /ALONG WITH THE 09.12 ECMWF/ WAS TO HAVE
SLIGHTS CONTINUE INTO MONDAY. DOES NOT LOOK PRECIP AMOUNTS WOULD BE
OVERWHELMING WITH THIS SYSTEM...BUT CONSIDERING MSP HAS ONLY
MEASURED 9 HUNDREDTHS OF AN INCH OF RAIN SINCE 1.33 INCHES FELL ON
AUGUST 6TH...WE WILL TAKE ANYTHING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1204 PM CDT TUE SEP 10 2013
A BAND OF -SHRA CONTINUED TO MOVE ACROSS EC/SC MN AND INTO WC WI
EARLY THIS AFTN. CIGS AND VSBYS REMAIN VFR AND WILL REMAIN VFR
THRU 00Z/11. HOWEVER...MVFR/IFR CIGS ARE NOTED ALONG THE FAR
NORTHERN PART OF MPX FA...WHICH COULD AFFECT KAXN IN THE NEXT HR
OR TWO. WILL CONTINUE WITH VFR CIGS AT KAXN...WITH MAYBE A
TEMPORARY PERIOD FOR AN HR OR TWO OF MVFR CIGS. OTHERWISE...NOT
MUCH AVIATION CONCERNS THRU THE AFTN WITH THE BULK OF THE TSRA
ACTIVITY SOUTH OF MPX FA. WINDS WILL REMAIN FROM THE SW TO W/WNW
DURING THE AFTN...WITH A MORE W/WNW DIRECTION OVERNIGHT...AND
BECOMING STRONGER AND GUSTY BY WEDNESDAY AFTN. SOME FG/BR IS
POSSIBLE AT KSTC/KRNH/KEAU...BUT CLOUD COVER MAY HINDER WIDESPREAD
DEVELOPMENT. SOMETHING TO WATCH BASED ON CURRENT MODEL TRENDS
DECREASING CLOUD COVER BY MORNING.
KMSP...
VCSH WILL CONTINUE THRU 21Z...WITH THE BULK OF THE RESTRICTIONS TO
VSBYS OCCURRING EAST OF THE TERMINAL BEGINNING AT 18Z. CIGS WILL
REMAIN AOA 11K THRU THE AFTN...WITH WINDS GENERALLY FROM THE
WSW/SW EARLY...MORE W/WSW AFTN 21Z. WINDS WILL SHIFT MORE WNW/NW
BY WEDNESDAY AFTN ALONG WITH A FEW GUSTS.
/OUTLOOK FOR KMSP/
THU...VFR. NNW WINDS 10-15 KTS.
FRI...VFR. E/SE WINDS 5 KTS.
SAT...VFR SW WINDS 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...RAH
LONG TERM...MPG
AVIATION...JLT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
317 PM CDT TUE SEP 10 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 317 PM CDT TUE SEP 10 2013
MORNING MAP ANALYSIS INDICATES A CLOSED MID LEVEL LOW OVER THE
SOUTHWESTERN CONUS...WITH RIDGING OVER THE EAST. A MID LEVEL
SHORTWAVE IS ALSO NOTED OVER SOUTH CENTRAL CANADA AND MOVING EAST.
THE PRIMARY AXIS OF MID TO UPPER LEVEL JET ENERGY EXTENDS FROM
WESTERN CANADA...SOUTHEAST INTO THE NORTHERN PLAINS...AND THEN
EAST/NORTHEAST INTO SOUTHEASTERN CANADA. MID TO UPPER LEVEL FLOW
IS FAIRLY WEAK OVER OUR AREA AS A RESULT...ONLY MAXING OUT AT
AROUND 30KTS AT VARIOUS POINT BETWEEN 500MB AND 200MB PER 12Z
SOUNDING DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY ALSO SHOWS
THE AFOREMENTIONED MID LEVEL LOW OVER THE SOUTHWESTERN CONUS...AS
WELL AS THE MID LEVEL SHORTWAVE OVER SOUTH CENTRAL CANADA. THE MID
LEVEL LOW OVER THE SOUTHWESTERN CONUS IS HELPING PULL MID LEVEL
MOISTURE NORTHWARD FROM MEXICO AND AS A RESULT...INCREASED VALUES
OF MID LEVEL MOISTURE ARE NOTED EXTENDING FROM THE SOUTHWESTERN
CONUS...NORTHEAST INTO THE ROCKY MOUNTAIN RANGE AND INTO PORTIONS
OF THE NORTHERN AND CENTRAL PLAINS. AT THE SURFACE A NEARLY
STATIONARY BOUNDARY IS NOTED EXTENDING FROM WESTERN KANSAS INTO
EASTERN NEBRASKA AND WESTERN IOWA. THIS BOUNDARY BISECTS OUR CWA
AND AS A RESULT...THE LOW LEVEL WIND FIELD ACROSS THE NORTHWESTERN
HALF OF OUR CWA REMAINS FROM THE NORTHEAST...WHILE LOCATIONS
FARTHER SOUTHEAST CONTINUE TO OBSERVE A SOUTHWESTERLY LOW LEVEL
WIND FIELD.
TO THE SOUTH OF THE LOW LEVEL BAROCLINIC ZONE...AFTERNOON SURFACE
TEMPERATURES HAVE CLIMBED WELL INTO THE 90S...WITH PROXIMITY
SOUNDINGS FROM LAPS AND RAP ANALYSIS INDICATING CONVECTIVE
TEMPERATURES HAVE BEEN REACHED. KUEX INDICATES ISOLATED SHOWER AND
THUNDERSTORM ACTIVITY DEVELOPING FROM WESTERN KANSAS INTO NORTH
CENTRAL KANSAS...INCLUDING SOUTHERN PORTIONS OF OUR CWA. THESE
SAME PROXIMITY SOUNDINGS SUGGEST ~1000J/KG OF POTENTIAL ENERGY IS
READY FOR UPDRAFT PRODUCTION...BUT VERY LITTLE IN THE WAY OF DEEP
LAYER BULK SHEAR IS PRESENT...PERHAPS NO HIGHER THAN 15 OR 20KTS.
GIVEN ALL THIS...ISOLATED SHOWER AND THUNDERSTORM ACTIVITY WILL
LIKELY PERSIST ACROSS SOUTHEASTERN PORTIONS OF OUR CWA THROUGH THE
REST OF THIS AFTERNOON. MULTIPLE SETS OF GUIDANCE SUGGEST LOW
LEVEL CONVERGENCE AND RESULTANT FORCING ALONG THE LOW LEVEL
BAROCLINIC ZONE MAY ALSO PROMOTE ISOLATED TO SCATTERED SHOWER AND
THUNDERSTORM CONVECTION ACROSS THE AREA. AS A RESULT...KEPT THE
~20% POP GOING ACROSS MUCH OF THE CWA 21-00Z.
ANY SURFACE-BASED CONVECTION THAT CAN BE REALIZED THIS AFTERNOON
AND/OR EVENING ACROSS OUR SOUTHERN COUNTIES...OR FARTHER NORTH
ALONG THE LOW LEVEL BAROCLINIC ZONE...SHOULD DISSIPATE SHORTLY
AFTER SUNSET AS DIABATIC HEATING IS LOST. THAT BEING
SAID...GUIDANCE SUGGESTS THE MID LEVEL SHORTWAVE...CURRENTLY OVER
SOUTH CENTRAL CANADA...WILL MOVE SOUTHEAST THUS PUSHING THE MID
LEVEL JET AXIS FARTHER SOUTH AS WELL. THIS WILL IN TURN PUSH A
30-40KT MID LEVEL JET STREAK FARTHER SOUTH INTO THE UPPER
MISSISSIPPI VALLEY AND PORTIONS OF THE NORTHERN PLAINS...WITH THE
RIGHT-REAR QUADRANT OF THIS JET STREAK SETTING UP OVER NORTHERN
PORTIONS OF OUR CWA. IT APPEARS AS THOUGH THERE WILL BE ENOUGH OF
A THERMALLY-DIRECT CIRCULATION AND RESULTANT OMEGA FOR ADDITIONAL
SHOWER AND THUNDERSTORM DEVELOPMENT...PRIMARILY ACROSS OUR
NORTH...OVERNIGHT TONIGHT AND AS A RESULT...~30% POPS HAVE BEEN
PLACED PRIMARILY ACROSS THE NORTHERN HALF OF OUR CWA 00-12Z
WEDNESDAY.
THERE MAY BE SOME LINGERING SHOWER AND THUNDERSTORM ACTIVITY EARLY
WEDNESDAY MORNING...BUT GUIDANCE SUGGESTS THIS ACTIVITY SHOULD
DISSIPATE BY AROUND SUNRISE. DRY CONDITIONS WILL MORE THAN LIKELY
BE OBSERVED THROUGH MUCH OF THE DAY WEDNESDAY...HOWEVER THE LOW
LEVEL BAROCLINIC ZONE...CURRENTLY OVER CENTRAL PORTIONS OF OUR
CWA...IS ONLY EXPECTED TO SHIFT SLIGHTLY SOUTH TONIGHT AND BY
WEDNESDAY AFTERNOON IS EXPECTED TO STRETCH ACROSS THE SOUTHEASTERN
ONE-THIRD OF OUR CWA. LOW LEVEL CONVERGENCE AND RESULTANT FORCING
ALONG THE LOW LEVEL BAROCLINIC ZONE MAY PROMOTE ANOTHER ROUND OF
AFTERNOON SHOWER AND THUNDERSTORM ACTIVITY ON WEDNESDAY AND AS A
RESULT...20-30% POPS HAVE BEEN PLACED ACROSS PORTIONS OF THE CWA
FOR WEDNESDAY AFTERNOON AND EVENING...WITH THE HIGHEST POPS
RELEGATED TO OUR SOUTHEAST IN CLOSEST PROXIMITY TO THE LOW LEVEL
BAROCLINIC ZONE.
GUIDANCE SUGGESTS POTENTIAL ENERGY WILL NOT CLIMB MUCH HIGHER THAN
1000J/KG THIS AFTERNOON AND EVENING...AND WITH LITTLE IN THE WAY
OF DEEP LAYER BULK SHEAR...THE THREAT FOR SEVERE WEATHER SEEMS
FAIRLY LIMITED. THAT BEING SAID...THERE IS A CHANCE UPDRAFT
STRENGTH COULD BE STRONG ENOUGH TO PROMOTE SOME HAIL...CURRENTLY
EXPECTED TO REMAIN SUB-SEVERE...AND SO WILL OUTLOOK THIS IN THE
HWO. IN ADDITION...FORECAST PROXIMITY SOUNDINGS SUGGEST FAIRLY
DEEP INVERTED-V SOUNDINGS...TO BETWEEN 800MB AND 750MB...COULD
ALSO PROMOTE A WIND GUST THREAT. WILL GO AHEAD AND OUTLOOK BRIEF
WIND GUSTS TO AROUND 50 MPH IN THE HWO FOR THIS AFTERNOON AND
EVENING AS WELL. TROPOSPHERIC CONDITIONS...FOR LOCATIONS NEAR AND
AHEAD OF THE LOW LEVEL BAROCLINIC ZONE...APPEAR AS THOUGH THEY
WILL BE SIMILAR ON WEDNESDAY WHEN COMPARED TO TODAY AND AS A
RESULT...WILL GO AHEAD AND OUTLOOK THE THREAT FOR SUB-SEVERE HAIL
AND WIND GUSTS...PRIMARILY ACROSS OUR SOUTH...FOR WEDNESDAY
AFTERNOON AND EVENING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 317 PM CDT TUE SEP 10 2013
WEDNESDAY NIGHT...THE SFC COOL FRONT WILL REMAIN WELL TO THE SOUTH
OF OUR FORECAST AREA AND WILL LIKELY BE LOCATED OVER OKLAHOMA. AN
UPPER LEVEL TROUGH WILL BE SCOOTING TO OUR NORTHEAST AND THE BEST
CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE ASSOCIATED WITH AN
OVERRUNNING SET UP ACROSS KANSAS. NEBRASKA WILL BE SO FAR NORTH OF
THE FRONT WITH DRIER AIR STARTING TO WORK IN AND HENCE LESSER POPS
AS YOU HEAD NORTH THROUGH OUR NEBRASKA ZONES.
THURSDAY AND FRIDAY...A SFC HIGH WILL SLIDE INTO THE GREAT LAKES
RESULTING IN A WIND SHIFT AS WE BEGIN TO GET MORE OF AN EASTERLY
UPSLOPE FLOW ON THURSDAY AND THEN A RETURN SOUTHEASTERLY STILL
SOMEWHAT UPSLOPE FLOW ON FRIDAY. THIS WILL RESULT IN THUNDERSTORM
CHANCES ACROSS THE HIGH PLAINS AND THEN SLIGHT CHANCES OF SHOWERS
AND THUNDERSTORMS ACROSS OUR FAR SOUTHWESTERN COUNTIES AS WESTERN
THUNDERSTORMS TRY TO MAKE IT EAST...BUT WILL LIKELY STRUGGLE. THE
TRI CITIES AND POINTS NORTH AND EAST ARE LIKELY GOING TO BE DRY
DURING THIS PERIOD. TEMPERATURES SHOULD BE BELOW NORMAL FOR THE
FIRST TIME SINCE AROUND THE MIDDLE OF AUGUST...WHICH WAS THE LAST
TIME WE SAW HIGHS ONLY IN THE 70S. ALTHOUGH BOTH THURSDAY AND
FRIDAY WILL BE COOL IN THE 70S FOR HIGHS...FRIDAY WILL BE THE
COOLEST OF THE TWO DAYS WITH HIGHS ONLY IN THE LOWER TO MID 70S.
WEEKEND...THE COOL WEATHER WILL PERSIST WITH CLOUDS AND SEVERAL
CHANCES OF SHOWERS AND THUNDERSTORMS AS WEAK PIECES OF A SHORTWAVE
TROUGH TRACK THROUGH THE CENTRAL PLAINS. PRECIPITATION CHANCES
SEEM FAIR GENERALLY IN THE 30 TO 40 PERCENT RANGE. THESE CHANCES
MAY BE RAISED IN COMING DAYS IF CURRENT WET LOOKING MODEL TRENDS
CONTINUE. HIGHS SHOULD CONTINUE TO BE IN THE 70S ACROSS NEBRASKA
TO NEAR 80 IN KANSAS. HOWEVER...COULD SEE THESE HIGHS BEING
LOWERED...PARTICULARLY ON SUNDAY...IF RAIN CHANCES INCREASE DUE TO
CLOUDS AND COOLER EAST NORTHEASTERLY FLOW. CONSEQUENTLY...THIS IS
A HEADS UP THAT OUR FORECAST HIGHS ARE CURRENTLY ON THE WARMER END
OF THE MODEL GUIDANCE...SO DO NOT BE SURPRISED IF HIGHS ARE
LOWERED WITH FUTURE FORECAST UPDATES.
MONDAY AND TUESDAY...CONFIDENCE IS LOW WITH SOME MODELS INDICATING
CONTINUED SHORT WAVES AND THUNDERSTORM CHANCES WHILE OTHER
FORECAST MODELS DRY OUT. POPS WILL BE LOW DUE TO UNCERTAINTY.
TEMPERATURES SHOULD BE SOMEWHAT NEAR NORMAL AND WILL BE CALLING
FOR HIGHS IN THE UPPER 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 109 PM CDT TUE SEP 10 2013
VFR9CONDITIONS ARE FORECAST THROUGH THE NEXT 24 HOURS.
CLEAR9SKIES WILL PERSIST THROUGH THE FIRST FEW HOURS OF THE
TAF...WITH INCREASING CLOUD COVER EXPECTED LATE THIS AFTERNOON
INTO WEDNESDAY MORNING. AT THIS TIME HOWEVER...THE CEILING AT GRI
IS NOT EXPECTED TO DROP BELOW 7000FT AGL. THE SURFACE WIND WILL
REMAIN LIGHT AND VARIABLE THROUGH THIS EVENING...BEFORE BECOMING
MORE ESTABLISHED FROM THE NORTHEAST...SUSTAINED AT AROUND
06KTS...STARTING 08Z WEDNESDAY. THERE IS A SLIGHT CHANCE OF SHOWER
AND THUNDERSTORM ACTIVITY LATE THIS AFTERNOON INTO THIS
EVENING...WITH A SOMEWHAT BETTER CHANCE DURING THE OVERNIGHT
HOURS. THAT BEING SAID...THE PROBABILITY OF SUCH ACTIVITY BEING
REALIZED AT GRI DURING THE TAF PERIOD IS TOO LOW FOR INCLUSION IN
THE TAF. SHOULD SHOWER AND/OR THUNDERSTORM ACTIVITY BE REALIZED AT
GRI...THEN VISIBILITY RESTRICTION IN PRECIPITATION WILL ALSO BE
POSSIBLE. BUT AGAIN...THE PROBABILITY OF SUCH ACTIVITY BEING
REALIZED AT GRI IS TOO LOW FOR INCLUSION IN THE TAF AND AS A
RESULT...VISIBILITY RESTRICTION IS NOT FORECAST AT GRI THROUGH THE
NEXT 24 HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...BRYANT
LONG TERM...WESELY
AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1251 PM CDT TUE SEP 10 2013
.AVIATION...
18Z TAFS FOR KOMA...KOFK...KLNK
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. SFC CDFNT IS
THROUGH OFK AND WILL BE MOVING THRU OMA/LNK AROUND 00-01Z. THIS
WILL ALLOW FOR THE SW WINDS AT OMA/LNK TO BECOME NORTHWEST AND AN
INCREASE IN CLOUDS. WE MAY ALSO SEE A FEW ISO SHOWERS DEVELOP THIS
AFTERNOON ALONG THE COLD FRONT WHERE THE MIXING IS MAXIMIZED.
THESE SHOWERS MAY CONT INTO THE OVERNIGHT HOURS ALONG AND BEHIND
THE FRNT...BUT WILL JUST INCLUDE AN EVENING SHOWER IN THE FORECAST
ATTM DUE TO UNCERTAINTY IN COVERAGE LATE IN THE PERIOD. OTHERWISE
A GOOD DEAL OF MID AND HIGH LEVEL CLOUDS WILL CONT THRU THE
PERIOD.
BOUSTEAD
&&
PREV DISCUSSION... /ISSUED 356 AM CDT TUE SEP 10 2013/
DISCUSSION...
FORECAST CONCERNS THROUGH WEDNESDAY EVENING WILL BE PRECIPITATION
COVERAGE ALONG AND BEHIND THE COLD FRONT...THEN COOLER AND DRIER
WEATHER THURSDAY AND FRIDAY.
LINCOLN TIED THEIR RECORD OF 100 DEGREES MONDAY SET BACK IN 1931.
OMAHA EPPLEY JUST MISSED THE RECORD WITH A HIGH OF 99 AND NORFOLK
TOPPED OUT AT 97. OMAHA DID TIE A RECORD WARM MINIMUM FOR MONDAY
WITH 75 DEGREES (TIED WITH 1983/1931 AND 1927).
THE 00Z UPPER AIR MAPS HAD A 90KT H3 JET OVER NORTH DAKOTA WITH THE
H5 TROF SIMILARLY OVER NORTH DAKOTA...EXTENDING SOUTHWEST TOWARD
ARIZONA AND SOUTHERN CALIFORNIA. WARM H7 TEMPERATURES OF +10 TO +13C
EXTENDED ACROSS MUCH OF THE CENTRAL PLAINS...WITH THE THERMAL
GRADIENT FROM NORTHWEST NEBRASKA NORTHWARD ACROSS THE NORTHERN
PLAINS. H7 MOISTURE WAS NOTED ON THE WATER VAPOR IMAGERY AND UA
CHARTS FROM THE SOUTHWEST U.S. INTO THE UPPER MIDWEST. AT H85 THE
THERMAL RIDGE EXTENDED FROM SOUTHWEST NEBRASKA AND NORTHWEST KANSAS
NORTHEAST ACROSS THE FORECAST AREA WITH THE GRADIENT COMPARABLE TO
THE H7 PATTERN ACROSS THE DAKOTAS. ALTHOUGH THE SURFACE FRONT HAS
PUSHED INTO THE CWA AND THE OAX RADAR SHOWED A BOUNDARY
APPROACHING VALLEY WITH A WIND SHIFT AT KFET. THE SURFACE WINDS
WERE LIGHT FROM THE SOUTH AT KOFK AGAIN. THE WSR-88D MOSAIC HAD
THE LEADING EDGE OF THE PRECIPITATION FROM BROKEN BOW TO MITCHELL
SOUTH DAKOTA INTO SOUTHWEST MINNESOTA AT 06Z AND BY 0830Z THERE
WERE A FEW ECHOES IN BOYD AND KNOX COUNTIES...BUT NOT MUCH
REACHING THE GROUND. THE TREND ON THE IR SATELLITE LOOP SHOWED
EXPANDING/COOLING TOPS WITH THE PRECIPITATION. WPC HAD THE
EXCESSIVE DAY 1 RAINFALL OVER THE SOUTHWEST U.S. INTO WESTERN
COLORADO.
TODAY...THE NORTHERN PLAINS SHORT WAVE TROF WILL CONTINUE TO SHIFT
EAST ACROSS MINNESOTA INTO WISCONSIN...WHILE THE H5 LOW OVER THE
SOUTHWEST U.S. CUTS OFF. THIS WILL SLOW THE PUSH OF THE FRONT TO
SOMEWHERE ALONG I80 THROUGH 00Z. THE LOW LEVEL JET WILL STRENGTHEN
THIS ACROSS NORTH CENTRAL KANSAS INTO CENTRAL NEBRASKA AND THE
OAX FORECAST AREA...WITH ISENTROPIC LIFT AND SATURATION NORTH OF
THE FRONT IN PARTS OF NORTHEAST NEBRASKA. THE FORCING THIS
MORNING WILL MAINLY BE NORTHWEST OF THE FORECAST AREA BUT COULD
CLIP THE COUNTIES NEAR THE SD BORDER. FARTHER SOUTH THE FORCING
IS MORE NEGLIGIBLE. THE MODELS ARE HINTING AT A SECOND AREA OF
SATURATION FARTHER SOUTH CLOSER TO I80...BUT FOR NOW WILL INCREASE
CLOUDS AND MAY INCLUDE SPRINKLES MENTION. THIS AFTERNOON...THERE
IS WEAK CONVERGENCE ALONG THE FRONT AND A DECENT THERMAL BOUNDARY
IS EXPECTED. MODELS KEEP IS MAINLY DRY...HOWEVER HRRR DOES
GENERATE PRECIP ALONG THE FRONT. WILL MAINTAIN ISOLATED POPS ALONG
AND BEHIND THE FRONT WHERE DEEPER MOISTURE IS PRESENT WITH COOLING
ALOFT. TEMPERATURES TODAY SHOULD BE HOT AHEAD OF THE FRONT AND
WHERE THERE IS SUNSHINE. CLOUDS WILL IMPACT HIGHS...BUT GENERALLY
HAVE READINGS AROUND 80 NORTH NEAR THE SD BORDER TO THE UPPER 90S
NEAR THE MISSOURI AND KANSAS BORDERS.
TONIGHT THROUGH WEDNESDAY NIGHT THE MID TROPOSPHERIC TROF
DEEPENS OVER THE GREAT LAKES AND THE SURFACE FRONT IS PUSHED
FARTHER SOUTH. MONSOONAL MOISTURE STREAMING INTO THE ROCKIES AND
MAKING IT INTO THE PLAINS...POOLING AHEAD OF THE TROF COMBINE WITH
THE LOW...MID AND UPPER LEVEL SUPPORT WILL PROVIDE AT LEAST SOME
CHANCES FOR PRECIPITATION DURING THE PERIOD...ALTHOUGH COVERAGE
STILL LOOKS SCATTERED TO ISOLATED FOR THE COUNTY WARNING AREA.
HIGHS WEDNESDAY SHOULD RANGE FROM THE LOWER 80S NORTH TO THE LOWER
90S SOUTH.
COOL HIGH PRESSURE BUILDS IN FOR THURSDAY AND FRIDAY WITH MAINLY
DRY CONDITIONS. NEAR NORMAL HIGHS AROUND 80S THURSDAY WITH BELOW
NORMAL HIGHS IN THE 70S FRIDAY.
SATURDAY THROUGH TUESDAY...AS THE SURFACE HIGH
RETREATS...SOUTHWEST FLOW WILL RETURN DEEPER MOISTURE TO THE AREA
AND SHOWERS WILL TRY TO RETURN TO THE WESTERN CWA FRIDAY NIGHT.
SHORTWAVE TROF ENERGY ADVANCES INTO THE PLAINS SATURDAY THROUGH
SUNDAY...SO THERE APPEARS TO BE A GOOD SHOT AT PRECIPITATION
DURING THIS PERIOD. BEYOND THIS PERIOD...THERE IS NOT GOOD MODEL
CONSENSUS...BUT PRECIP CHANCES COULD LINGER INTO MONDAY. HIGHS
STILL BELOW NORMAL FOR MUCH OF THE EXTENDED.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1225 PM CDT TUE SEP 10 2013
.UPDATE...
UPDATED AVIATION DISCUSSION BELOW FOR 18Z TAFS.
SOME RR QUADRANT JET STREAK AND MID LEVEL FRONTAL ZONE CLOUDS
WILL STREAM OVER THE CWA FROM SOUTHWEST TO NORTHEAST THROUGH THE
DAY. ALSO...VISIBLE SATELLITE SHOWS STRATUS/STRATOCU CLOUDS
HEADING SOUTH INTO NORTHERN SD/WEST CENTRAL MN LATE THIS MORNING.
THESE ARE EXPECTED TO MIX OUT SOME AND BE MORE SCATTERED AS THEY
MOVE ACROSS THE EASTERN PART OF THE CWA. OVERALL...SKIES WILL BE
PARTLY CLOUDY THROUGH THE DAY WITH STEADY NORTHWEST BREEZES.
EXPECT ANY SHOWER/THUNDER ACTIVITY TO REMAIN SOUTH OF OUR CWA THIS
AFTERNOON ALONG THE FRONTAL ZONE. MIXED OUT HIGHS WILL BE AROUND
80 TO 85 DEGREES BY LATE AFTERNOON. FORECAST LOOKS GOOD.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH THURSDAY
A BAND OF RAIN SHOWERS CONTINUES ACROSS PARTS OF SOUTH CENTRAL
SOUTH DAKOTA THROUGH WEST CENTRAL MINNESOTA THIS MORNING. THIS IS
MAINLY INFLUENCING THE SIOUX FALLS CWA...HOWEVER...IT DOES REQUIRE
POPS ACROSS THE FAR SOUTHERN TIER OF COUNTIES THROUGH MOST OF THE
MORNING HOURS TODAY. THIS IS CURRENTLY THE ONLY CHANCE FOR
PRECIPITATION THROUGH THE SHORT TERM FORECAST...AS THE ENERGY
ASSOCIATED WITH THE UPPER SHORTWAVE TROUGH MOVES NORTHEAST INTO
THE ONTARIO REGION TODAY. NORTHWEST FLOW FOLLOWS....AND WILL
PREVAIL ACROSS THE DAKOTAS THROUGH THE SHORT TERM. ANOTHER TROUGH
DOES DROP OUT OF CANADA AND ACROSS NORTH DAKOTA ON WEDNESDAY...BUT
THE BEST FORCING WILL REMAIN NORTH AND EAST OF THIS CWA. AN
ASSOCIATED SURFACE COLD FRONT WILL DROP SOUTHWARD AS WELL. SO WITH
SLIGHTLY ABOVE NORMAL TEMPERATURES TODAY AND WEDNESDAY...TEMPERATURES
WILL DROP TO NEAR NORMAL VALUES ON WEDNESDAY NIGHT AND THURSDAY
BEHIND THE FRONT. THE SURFACE HIGH CENTER WILL REMAIN IN
CANADA...HOWEVER THE RIDGE WILL EXTEND ACROSS THE DAKOTAS AND
WINDS WILL GO LIGHT THURSDAY MORNING. ALONG WITH COLD AIR
ADVECTION AND CLEAR SKIES...THURSDAY MORNING LOWS WILL BE DROPPING
INTO THE MID 40S ACROSS THE NORTH. HIGHS ON THURSDAY WILL THEN BE
IN THE LOW TO UPPER 70S.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
A COOL/DRY CANADIAN-SOURCED AIRMASS SHOULD BE SETTING UP SHOP
ACROSS THE CWA AS THE PERIOD OPENS. A RATHER AMPLIFIED/BLOCKY
UPPER FLOW PATTERN WILL ONLY HAD ANOTHER LAYER OF FORECAST
DIFFICULTY TO SYSTEM TIMING/PLACEMENT/STRENGTH OVER THE WEEKEND AS
AN UPPER LOW DEPICTED IN WATER VAPOR IMAGERY OUT OVER ARIZONA
MEANDERS ITS WAY UP INTO THE CENTRAL/NORTHERN PLAINS. THE 00Z
GFS/CANADIAN/ECMWF DETERMINISTIC SOLUTIONS ALL CONTINUE TO SPREAD
PRECIPITATION UP INTO THE CWA LATE FRIDAY NIGHT. THE PRECIP SHIELD
THEN SLOWLY SPREADS NORTH AND EAST ACROSS THE CWA
SATURDAY/SATURDAY NIGHT. NOT A WHOLE LOT OF STEERING FLOW ALOFT
OVER THE CWA DURING THE EXTENDED FORECAST PERIOD. SO...IF THE RAIN
FORECAST PANS OUT...THERE IS CERTAINLY THE POTENTIAL FOR A
RAIN-COOLED BOUNDARY LAYER TO SATURATE BY SATURDAY NIGHT AND
PRODUCE EITHER FOG OR LOW STRATUS. WITHOUT A REAL NOTEWORTHY
PRESSURE FIELD/GRADIENT OR MIXING WIND ANTICIPATED...PARTIAL TO
WIDESPREAD STRATUS CONDITIONS COULD BE ADDING A NEW WRINKLE TO THE
FORECAST FOR SUNDAY/MONDAY.
DURING THE FORECAST PERIOD...TEMPERATURES ARE NOT EXPECTED TO STRAY
MORE THAN A FEW DEGREES EITHER SIDE OF CLIMO NORM FOR
MID-SEPTEMBER.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH A WNW
BREEZE AND PASSING MID/HIGH LEVEL CLOUDS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR/TMT
SHORT TERM...SERR
LONG TERM...DORN
AVIATION...TMT
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1248 PM CDT TUE SEP 10 2013
.DISCUSSION...SEE 18Z AVIATION DISCUSSION.
&&
.AVIATION...MAIN ISSUE IS THE CONVECTION THIS AFTERNOON AND THIS
EVENING (A BIT LESS OF A CONCERN FOR 12Z-18Z WEDNESDAY).
CONVECTION ON THE WANE NEAR THE COAST...BUT STILL A POTENTIAL FOR
SOMETHING IN KCRP BEFORE 20Z SO HAD TO KEEP VCTS. FARTHER WEST AND
NORTH...POTENTIAL FOR CONVECTION (TSRA) AT KVCT AND KALI TIL ABOUT
22Z/23Z...THEN AT KLRD TIL ABOUT 11/00Z. WINDS SHOULD BEGIN TO
INCREASE WITH END OF CONVECTION ALL SITES (OBVIOUSLY THE FARTHER
EAST THE SOONER IN THE TERMINAL FORECAST)...BUT THEN DIE DOWN
AGAIN AND MAINLY EAST A COUPLE OF HOURS AFTER SUNSET. DRIER MID
LEVEL AIR STARTS TO COME IN TONIGHT FROM THE NORTHEAST...SO THINK
ANY CONVECTIVE ACTIVITY FOR WEDNESDAY THROUGH 18Z WILL BE
RESTRICTED TO THE KCRP AND KALI TERMINALS. HOWEVER...WITH IT BEING
SO LATE IN THE FORECAST...WILL ONLY GO WITH VCTS AND KCRP AND VCSH
AT KALI AFTER 12Z (NO MENTION ELSEWHERE)...SINCE CONFIDENCE IN
GETTING INTO THE TERMINAL ITSELF IS NOT HIGH. CONCERNING CIGS
OUTSIDE OF CONVECTION...AM EXPECTING MVFR CONDITIONS AT KLRD TWD
12Z WEDNESDAY OTHERWISE VFR CONDITIONS FOR CIGS. CONCERNING FOG
OUTSIDE OF CONVECTION...MAY SEE SOME AT KVCT AGAIN TOWARD 12Z BUT
FOR NOW AM ONLY GOING TO GO WITH NEAR MVFR 08Z ENDING BY 14Z. EAST
WINDS LESS THAN 11 KNOTS AFTER 12Z WEDNESDAY.
&&
.PREV DISCUSSION... /ISSUED 1011 AM CDT TUE SEP 10 2013/
DISCUSSION...LOWERED TEMPERATURES MAINLY SOUTHEASTERN SECTIONS
AND INCREASED POPS JUST A TAD OVER THE SOUTHERN COASTAL AREAS. RUC
AND HRRR IS SHOWING CONVECTION CONTINUING NEAR THE SOUTHERN
COASTAL AREAS FROM TIME TO TIME TIL EARLY AFTERNOON BEFORE MOST
OF IT PUSHES INLAND. CAN BELIEVE THIS GIVEN RADAR TRENDS/HISTORY
AND OBSERVED/FORECAST SURFACE FORCING. MORNING SOUNDING VERY
WET...WITH LITTLE TO NO CONVECTIVE INHIBITION. THUS...SCATTERED
CONVECTION (MORE NUMEROUS SOUTHERN COASTAL AREAS) SEEMS REASONABLE
THIS MORNING...WITH ACTIVITY PUSHING FARTHER WEST DURING THE
AFTERNOON ONCE ENOUGH DAYTIME HEATING GETS GOING TO GET A SEA-
BREEZE STARTED. OTHER ADJUSTMENTS TO FIRST AND SECOND PERIOD
GRIDS. PRODUCTS ARE OUT. MARINE FORECAST FOR NOW LOOKS REASONABLE.
PREV DISCUSSION... /ISSUED 643 AM CDT TUE SEP 10 2013/
DISCUSSION...UPDATED FOR THE 12Z AVIATION DISCUSSION.
AVIATION...GENERAL VFR CONDITIONS...WITH BRIEF MVFR CIGS/IFR
VSBYS IN AND AROUND SHOWERS/STORMS. RAIN COVERAGE IS EXPECTED TO
INCREASE...ESPECIALLY ACROSS THE COASTAL PLAINS FROM CRP-ALI-VCT
THROUGH THE LATE MRNG/EARLY AFTN. ISOLATED DEVELOPMENT IS EXPECTED
TO REACH LRD BY MID AFTN...THEREFORE WILL ONLY MAINTAIN VCTS IN
TAFS FOR NOW. THE TROPICAL AIRMASS WILL LEAD TO MOSTLY SHOWER
ACTIVITY...HOWEVER WITH ADDITIONAL HEATING AND WEAK UPPER LEVEL
SUPPORT...THUNDER REMAINS POSSIBLE DURING THE LATE MRNG/AFTN/EVNG
HOURS. ACTIVITY SHOULD WANE FROM EAST TO WEST THROUGH THE EVENING.
GENERAL EASTERLY WINDS 10-15 KTS ARE EXPECTED TO DEVELOP INTO THE
AFTERNOON BEFORE DECOUPLING THIS EVENING.
PREV DISCUSSION... /ISSUED 417 AM CDT TUE SEP 10 2013/
SHORT TERM (TODAY THROUGH WEDNESDAY)...ISOLATED SHOWERS DEVELOPING
ACROSS PORTIONS OF SOUTH TEXAS THIS MORNING DUE TO PWATS NEAR 2
AND SURFACE COASTAL TROUGH SOUTH OF THE AREA WITH WEAK PVA AT H5
ACROSS THE NORTHEASTERN CWA. ADDITIONAL COVERAGE IS EXPECTED TO
DEVELOP THROUGH THE LATE MORNING AND AFTERNOON...WITH HIGHER
CHANCE POPS MAINLY ACROSS THE EASTERN HALF OF THE CWA. AN UPPER
WEAK JET STREAK SHOULD PROVIDE A BIT MORE DIFFLUENT FLOW ACROSS
THE AREA...WHICH MAY LEAD TO A FEW STORMS BECOMING STRONG THIS
AFTERNOON...PARTICULARLY OVER THE COASTAL PLAINS. OTHERWISE...MOST
ACTIVITY SHOULD REMAIN AS SHOWERS WITH GENERAL THUNDER. DUE TO
DEEP TROPICAL MOISTURE...LOCALLY HEAVY RAINFALL CAN BE
EXPERIENCED. RAIN CHANCES WILL THEN TAPER OFF THROUGH THE EVENING
HOURS WITH THE LOSS OF HEATING. THE MID/UPPER LEVEL RIDGE ACROSS
THE EASTERN U.S. WILL SLOWLY SHIFT WESTWARD THROUGH WEDNESDAY WITH
DRIER AIR APPROACHING FROM THE NORTHEAST. HOWEVER PWATS NEAR 1.8
INCHES WILL REMAIN ACROSS THE SOUTH TEXAS...LEADING TO A SLIGHT
CHANCE TO LOW END CHANCE POPS FOR SHOWERS THROUGH WEDNESDAY. AS
FOR TEMPERATURES...HIGHS ARE DEPENDENT ON CLOUD AND RAIN
COVERAGE...HOWEVER WITH BETTER CHANCES FOR RAIN ACROSS THE COASTAL
BEND...WILL MAINTAIN TEMPS IN THE UPPER 80S...WITH LOWER 90S
FARTHER INLAND. SLIGHTLY WARMER TEMPERATURES ARE EXPECTED FOR
WEDNESDAY.
LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...MODELS CONTINUE TO
INDICATED MID LEVEL DRYING OCCURS FROM NORTHEAST TO SOUTHWEST
THURSDAY AND FRIDAY...AS THE MID AND UPPER LEVEL RIDGE ACROSS THE
SOUTHEAST U.S. BUILDS BACK TO THE WEST. PRECIPITABLE WATER VALUES
FALL TO 1.6-1.8 INCHES ON THURSDAY AND TO LESS THAN 1.5 INCHES ON
FRIDAY. EXPECT COVERAGE OF SHOWERS AND THUNDERSTORMS TO DECREASE
TO ISOLATED...WITH BEST CHANCES FOR PRECIP MAINLY ACROSS MARINE AND
SOUTHERN AREAS OF THE CWA.
ATTENTION SHIFTS TO THE BAY OF CAMPECHE DURING THE LATTER HALF OF
THE WEEK AND INTO THE WEEKEND. AN AREA OF DISTURBED WEATHER LOCATED
OVER THE NORTHWESTERN CARIBBEAN SEA IS MOVING WESTWARD AND IS
FORECAST TO MOVE ACROSS THE YUCATAN PENINSULA AND INTO THE BAY OF
CAMPECHE BY LATE THURSDAY. MODELS ARE INDICATING AN AREA OF BROAD
LOW PRESSURE TO FORM IN THE BAY OF CAMPECHE...AND NHC HAS
HIGHLIGHTED THIS REGION FOR A HIGH CHANCE OF TROPICAL CYCLONE
DEVELOPMENT DURING THIS TIME. GFS AND ECMWF INDICATE EITHER WAVE OR
CLOSED LOW MOVING WEST-NORTHWEST INTO VERACRUZ OR TAMAULIPAS MEXICO
SUNDAY OR MONDAY. HOWEVER...MODELS ARE INDICATING THE MID AND UPPER
LEVEL RIDGE ACROSS TO BUILD BACK INTO THE SOUTHEAST U.S. DURING THIS
TIME...ALLOWING DEEP SURGE OF TROPICAL MOISTURE NORTH OF THE
POTENTIAL SYSTEM TO POSSIBLY MAKE IT INTO SOUTH TEXAS. HAVE RAISED
POPS INTO THE HIGH END SCATTERED RANGE SUNDAY AND MONDAY AND LOWERED
FORECAST HIGHS. FURTHER FORECAST ADJUSTMENTS SUNDAY AND MONDAY ARE
LIKELY GIVEN THE UNCERTAINTY. FINALLY...AN INCREASE IN LONG PERIOD
SWELLS AND DEEP EASTERLY FETCH WILL LEAD TO AN INCREASE IN THE RIP
CURRENT THREAT ALONG THE BARRIER ISLANDS OVER THE WEEKEND AND INTO
EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 87 77 93 76 93 / 60 20 20 20 30
VICTORIA 91 74 93 74 94 / 50 20 20 10 20
LAREDO 95 75 96 76 95 / 30 20 30 20 30
ALICE 87 74 90 74 92 / 50 20 20 10 30
ROCKPORT 88 78 91 78 90 / 50 20 20 20 20
COTULLA 92 74 95 73 95 / 40 20 20 20 20
KINGSVILLE 87 75 92 75 93 / 50 20 30 20 30
NAVY CORPUS 87 77 90 78 89 / 60 20 20 20 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...AVIATION
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
337 PM CDT TUE SEP 10 2013
.SHORT TERM...
TONIGHT...FORECAST CONFIDENCE MEDIUM
BROAD 500 MILLIBAR TROUGH SHIFTING EAST FROM THE NORTHERN PLAINS.
WATER VAPOR SHOWS MOISTURE PLUME AND JET MAX FROM SOUTH DAKOTA TO
LAKE SUPERIOR. ANOTHER MOISTURE PLUME LIFTING NNE FROM IOWA. 12Z
4.5KM SPC WRF APPEARS TOO QUICK ON DEVELOPMENT THIS AFTERNOON
ACROSS SW WI. LEANING MORE TOWARDS HRRR SOLUTION WITH DEVELOPMENT
NORTH OF THE CWA AND THEN JUST OOZING INTO CWA LATER THIS EVENING
AND OVERNIGHT. FRONT WILL NOT HAVE MUCH OOMPH INTO SRN WI AS THE
NIGHT GOES ON SO INSTABILITY EVEN LESS THAN THE AFTN 500-1000
J/KG...SO CONFIDENCE NOT GREAT THAT ANYTHING REORGANIZED WILL
SURVIVE TOO DEEP INTO SRN WI.
WEDNESDAY...FORECAST CONFIDENCE MEDIUM
WEAK 850 MILLIBAR CONVERGENCE ALONG WITH 500 MILLIBAR CYCLONIC
FLOW WILL RESULT IN SMALL POPS ACROSS MAINLY THE SOUTHERN CWA. 12Z
NAM IS DRY WHILE OTHER MODELS SHOWING LIGHT QPF. BULK OF ACTIVITY
LOOKS LIKE IT WILL BE FURTHER SOUTH OF THE STATE WITH BETTER
INSTABILITY. 925 TEMPS AVERAGED AMONGST THE MODELS SHOWS 21-23C
WHICH YIELDS QUITE A BIT OF HIGHS IN THE MID 80S.
WEDNESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
THE INITIAL...WEAK COLD FRONT WILL SLIDE SWD INTO NRN IL AND NRN
IN BY WED EVENING WITH ANY TSTORM DEVELOPMENT EXPECTED THERE. THE
SECONDARY AND STRONGER COLD FRONT WILL THEN ARRIVE FROM THE NORTH
LATE WED NT. A SHARP CANADIAN UPPER TROUGH WILL ACCOMPANY THE
FRONT AND MOVE INTO THE NRN GRTLKS AND WI BY 12Z THU AND WILL MOVE
EAST OF WI BY FRI. LOW LEVEL INSTABILITY VIA COLD AIR ALOFT MAY
LEAD TO SCT SHOWERS OVER THE ERN CWA THU INTO THU EVENING. A NNELY
1000-850 MB FLOW AND LAKE TO 850 MB TEMP DIFFERENCES OF 13C OR
GREATER MAY CONTRIBUTE TO THE SHOWER POTENTIAL OVER THE LAKE
COUNTIES AS WELL. THE COLD AND DRY AIR ADVECTION TO SLOW DOWN BY
THU NT WITH MORE SUN THEN EXPECTED FOR FRI AS THE CANADIAN HIGH
CENTERS OVER WI. EXPECTED 925 MB TEMPS OF THE MID TO UPPER TEENS
CELSIUS FOR THU AND AROUND 10C FOR FRI...WILL YIELD HIGHS IN THE
MID 70S FOR THU AND LOWER TO MID 60S FOR FRI.
.LONG TERM...
SATURDAY THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM
THE MAIN POLAR JET STREAM WILL REMAIN IN CANADA WITH ANOTHER
STRONG UPPER TROUGH AND LOW PRESSURE AREA MOVING ACROSS CANADA. SWLY
WINDS AND WARMER TEMPS WILL RETURN FOR SAT AND SUN OVER SRN WI
AHEAD OF THE TRAILING CANADIAN COLD FRONT THAT WILL PASS ON
SUNDAY. ONLY SMALL CHANCES FOR PCPN WITH THE FRONT. CANADIAN HIGH
PRESSURE WILL THEN TRACK FROM THE NRN GRTLKS SUN NT TO THE ERN
GRTLKS FOR MON AND POSSIBLY TUE. A DRY ELY FLOW WILL PREVAIL OVER
THE AREA WITH PLEASANT AND NEAR TO SLIGHTLY BELOW NORMAL TEMPS.
&&
.AVIATION/00Z TAFS/...VFR SKC INTO THE EVENING HOURS FOR TAF SITES.
EXPECT MID CLOUDS TO INCREASE TONIGHT AS FRONTAL BOUNDARY SAGS SOUTH
AND INFLUENCE OF UPPER JET ENHANCES VERTICAL MOTION. LATEST HRRR
KEEPS CONVECTION NORTH OF TAF SITES THROUGH 05Z. WILL BRING SOME
SHRA/TSRA INTO THE AREA LATER IN THE NIGHT. THE NAM IS THE ONLY
MODEL NOT SHOWING PRECIP WEDNESDAY. WARY THAT SOME SHRA WILL
LINGER THOUGH FORCING NEAR NIL ONCE LOW LEVEL BOUNDARY SAGS SOUTH.
&&
.MARINE...A FEW SOUTHWEST WIND GUSTS EXCEEDING CRITERIA SO WILL
LEAVE SMALL CRAFT GOING UNTIL 7 PM.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
TONIGHT/WEDNESDAY AND AVIATION/MARINE...COLLAR
WEDNESDAY NIGHT THROUGH TUESDAY...GEHRING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
244 PM CDT TUE SEP 10 2013
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 244 PM CDT TUE SEP 10 2013
SURFACE MAP HAS LOW PRESSURE OVER LAKE SUPERIOR WITH A COLD FRONT
EXTENDING THROUGH CENTRAL UPPER MI TO JUST NORTH OF LA CROSSE...AND
THEN THROUGH NORTHERN IA. RADAR MOSAIC WAS SHOWING A SCATTERED BAND
OF POST-FRONTAL SHOWERS ACROSS WESTERN UPPER MI THROUGH NORTH
CENTRAL WI INTO SOUTHERN MN. NOT MUCH OF THIS REFLECTIVITY WAS BEING
REALIZED AT THE SURFACE...AND WHERE IT WAS...RAINFALL WAS SCANT WITH
GENERALLY .02 INCH OR LESS. PER THE RAP MODEL...THIS BAND OF SHOWERS
WAS TIED TO SOME 850-700MB FRONTOGENESIS BEHIND THE SURFACE FRONT.
OTHERWISE...TEMPERATURES ACROSS THE AREA RANGED FROM NEAR 80 ACROSS
NORTH CENTRAL WI...TO A FEW LOWER 90S ACROSS NORTHEAST IA INTO
SOUTHWEST WI.
SO...MAIN FORECAST CHALLENGE WILL BE RAIN CHANCES TONIGHT INTO
WEDNESDAY WITH THE PASSAGE OF THIS FRONT AND POST-FRONTAL FORCING.
LOOK FOR THE THE MAIN SURFACE FRONT TO CONTINUE PUSHING SOUTHEAST
THROUGH THE AREA TONIGHT WHILE 850-700MB FRONTOGENESIS LAGS BEHIND.
RAP SHOWING 850-700MB FG-FORCING...ALBEIT NOT OVERLY
STRONG...MAINTAINING ITSELF AS IT DRIFTS SOUTHEAST ACROSS THE AREA
THIS EVENING/OVERNIGHT. THE NAM ACTUALLY SHOWS THIS FORCING
INTENSIFYING A BIT...BUT MORE ACROSS EAST CENTRAL WI. BASED ON WHAT
IS HAPPENING NOW AND FORECAST FORCING SIGNAL...HAVE DOWNPLAYED
RAIN CHANCES AND DROPPED THUNDER MENTION AS FORCING AND CAPE WANE.
PLAN ON OVERNIGHT LOW TEMPERATURES IN THE UPPER 50S TO THE MIDDLE
60S.
FOR WEDNESDAY...WILL BE WATCHING THE COLD FRONTAL BOUNDARY CONTINUE
TO SLIP SOUTH OF OUR AREA WITH 850-700MB FG-FORCING ALMOST
NON-EXISTENT. AS SUCH...PUSHED ANY REMAINING SHOWER CHANCES SOUTH OF
THE FORECAST AREA BY AFTERNOON. OTHERWISE...LOOKING AT A MID-LEVEL
TROUGH/REINFORCING SHOT OF COOLER AIR DROPPING INT NORTHERN WI BY
LATE IN THE AFTERNOON. MODELS ARE PRODUCING SOME SHRA/ISOLATED
THUNDER WITH THIS WAVE...BUT KEEPING IT NORTH OF THE FORECAST AREA.
OTHERWISE...LOOK FOR HIGHS ACROSS THE FORECAST AREA IN THE 80-85
DEGREE RANGE.
COOLER/DRIER AIR FILTERS IN FOR WEDNESDAY NIGHT AS HIGH PRESSURE
BUILDS INTO THE UPPER MISSISSIPPI RIVER REGION FROM THE CENTRAL
CANADIAN PROVINCES. LOOK FOR OVERNIGHT LOWS IN THE 50-60 DEGREE
RANGE WITH NORTHWEST WINDS OF 5-10 MPH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 244 PM CDT TUE SEP 10 2013
CONTINUED DRY/COOL FLOW CONTINUES INTO THE AREA ON THURSDAY AS HIGH
PRESSURE BUILDS IN ACROSS THE NORTHERN PLAINS/MN. FAIRLY STEEP LAPSE
RATES WILL BE IN PLACE WITH 925MB TEMPERATURES IN THE 10-17C RANGE
AND 500MB IN THE -5 TO -15C RANGE. THIS IS EXPECTED TO PRODUCE A
PRETTY GOOD FIELD OF CUMULUS/STRATOCUMULUS...ESPECIALLY AREAS
NORTHEAST OF I-94. ANY SHOWER THREAT LOOKS TO STAY NORTH OF THE
AREA.
HIGH PRESSURE WILL CONTINUE TO DOMINATE THE WEATHER PICTURE THURSDAY
NIGHT THROUGH SATURDAY. THURSDAY NIGHT AND ESPECIALLY FRIDAY NIGHT
WILL SET UP FAVORABLE RIVER VALLEY FOG CONDITIONS WITH CLEAR SKIES
AND LIGHT/CALM WINDS. RATHER CHILLY OVERNIGHT LOWS ARE ALSO EXPECTED
THURSDAY NIGHT AND FRIDAY NIGHT WITH PLANNED FORECAST LOWS
DROPPING INTO UPPER 30S IN THE FAVORED COLD SPOTS ALONG AND
NORTHEAST OF I-94. WILL HAVE TO WATCH CLOSELY FOR THE POTENTIAL OF
PATCHY FROST ACROSS THIS AREA THURSDAY NIGHT AS THE COLDEST CORE OF
AIR ALOFT SINKS ACROSS THE REGION.
WILL BE WATCHING THE HIGH DRIFT EAST OF THE AREA SATURDAY NIGHT INTO SUNDAY
AS A FAIRLY VIGOROUS //AT LEAST ACCORDING TO THE ECMWF//
MID-LEVEL TROUGH AND SURFACE COLD FRONT DROPS SOUTHEAST INTO THE
AREA. THE GFS IS NOT AS ENTHUSED AS THE ECMWF. NEW 12Z ECMWF LOOKING
MORE LIKE THE GFS NOW....KEEPING POPS SPLIT TO THE NORTH AND SOUTH
OF THE AREA. LOWERED POPS FOR NOW...BUT IF TREND CONTINUES...COULD
PROBABLY DROP POPS ALTOGETHER FOR THE AREA. WILL KEEP AN EYE ON
THIS.
A STRONG AREA OF CANADIAN HIGH PRESSURE BUILDS INTO THE AREA FOR
SUNDAY NIGHT AND HOLDS AT LEAST THROUGH MONDAY NIGHT. THIS IS
EXPECTED TO YIELD DRY CONDITIONS WITH SLIGHTLY BELOW NORMAL
TEMPERATURES THROUGH THE PERIOD. LOOK FOR OVERNIGHT LOWS IN THE
UPPER 40S TO THE LOWER 50S WITH HIGHS IN THE MIDDLE 60S TO AROUND
THE 70 DEGREE MARK.
THE ECMWF AND GFS THEN DIFFER A BIT WITH SPEED OF A SHORTWAVE TROUGH
PUSHING EAST OUT OF THE PLAINS ON TUESDAY. THE ECMWF IS THE FASTER
OF THE TWO...SPREADING SHOWER/THUNDERSTORM CHANCES IN DURING THE
DAY. THE GFS IS MUCH SLOW AND MAINTAINS RIDGING ACROSS THE AREA.
WILL KEEP A DRY/COOL FORECAST GOING FOR NOW AND WAIT FOR BETTER
MODEL CONSENSUS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1248 PM CDT TUE SEP 10 2013
AT 10.18Z...A COLD FRONT EXTENDED FROM JUST SOUTH OF MARSHFIELD
WISCONSIN TO AUSTIN MINNESOTA. BEHIND THIS FRONT...THERE IS A BROKEN
DECK OF 10-15K OF CLOUDS. FURTHER TO THE NORTHWEST...ANOTHER COLD
FRONT EXTENDED FROM DULUTH TO REDWOOD FALLS. AHEAD OF THIS FRONT
THERE IS A NARROW BAND OF SHOWERS. 10.12Z MESO MODELS SUGGEST THAT
THE FRONTOGENETIC FORCING ALONG THE NORTHERN FRONT WILL
DRAMATICALLY WEAKEN THIS AFTERNOON AND INCREASE ALONG THE SOUTHERN
FRONT. AS THIS OCCURS...THERE WILL BE THE POTENTIAL THAT BOTH TAF
SITES WILL MISS OUT ON THE SHOWERS. FELT CONFIDENT TO REMOVE THE
SHOWERS AT KRST...AND TIGHTENED THE TIME PERIOD OF THEIR
OCCURRENCE AT KLSE TO BETWEEN 11.04Z AND 11.08Z. BETWEEN 11.11Z AND
11.14Z...THE 10-15K FOOT DECK WILL LIKELY BECOME SCATTERED AS THE
FRONT CONTINUES TO PUSH AWAY FROM THE REGION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....BOYNE