Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/14/14
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
800 PM MST SAT SEP 13 2014
.SYNOPSIS...
AN INCREASE IN MOISTURE FROM THE EAST WILL MAINTAIN A SLIGHT CHANCE
THUNDERSTORMS THROUGH MONDAY. DEEPER TROPICAL MOISTURE WILL BEGIN TO
MOVE IN TUESDAY FOR A SIGNIFICANT INCREASE IN STORM CHANCES THE REST
OF NEXT WEEK.
&&
.DISCUSSION..
AT 03Z SKIES WERE MOSTLY CLEAR THIS SATURDAY EVENING WITH NO SHWRS
ACROSS THE ENTIRE FORECAST AREA...SOUTHEAST CA TO SOUTH CENTRAL AZ.
BOUNDARY LAYER MOISTURE DID INCREASE SOMEWHAT ACROSS THE REGION
UNDER BREEZY LOW LEVEL SOUTHEASTERLY WINDS SATURDAY. HOWEVER...
WINDS ALOFT WERE MOSTLY CONVERGENT AND NOT VERY SUPPORTIVE OF ANY
TALL CONVECTION. A FEW LOW TOPPED AFTERNOON MOUNTAIN SHWRS/TSTMS...
MOST NOTABLY OVER THE MOGOLLON...AND SOME NEAR THE MEXICAN BORDER
HAVE DISSIPATED.
LOW LEVEL SOUTHEASTERLY WINDS WILL DIMINISH THE REMAINDER OF THIS
EVENING WITH NOT MUCH MORE MOISTURE INPUT INTO THE REGION SUNDAY.
THEREFORE A REPEAT DAY IS EXPECTED SUNDAY AFTERNOON WITH MOSTLY A
LOW THREAT OF LOW TOPPED MOUNTAIN CONVECTIVE STORMS. EARLIER UPDATES
WERE TO REMOVE CONVECTIVE THREATS FOR THE REMAINDER OF TONIGHT
ACROSS THE FORECAST AREA...AND REMOVE CONVECTIVE THREATS FOR OUR
PHOENIX ZONE 23 JUST FOR THE AFTERNOON PERIOD SUNDAY.
.PREVIOUS DISCUSSION...350 PM MST...
REST OF TODAY THROUGH MONDAY...
TIGHT SURFACE PRESSURE GRADIENT ACROSS ARIZONA AND NEW MEXICO WITH
LOWER PRESSURE OVER THE MOHAVE DESERT AND HIGH PRESSURE OVER THE
PLAINS. THIS IS DUE TO A BACK DOOR COLD FRONT SPILLING OVER THE
SOUTHERN CONTINENTAL DIVIDE. BREEZY EASTERLY WINDS HAVE RESULTED AS
HAVE HIGHER DEW POINTS AND COOLER TEMPERATURES...MOST NOTICEABLY
OVER EASTERN PORTIONS OF OUR FORECAST AREA. THE INCREASED MOISTURE
HOWEVER LOOKS TO BE OFFSET BY AN INCREASE IN CIN...AT LEAST OVER
SOUTHERN ARIZONA. NCEP MODELS AS WELL AS HRRR AND LOCAL HI-RES
MODELS ARE NOT VERY ENTHUSIASTIC ABOUT STORM ACTIVITY THE REST OF
TODAY AND TONIGHT FOR OUR AREA. HOWEVER...WITH THE MOISTURE THERE IS
A SLIGHT CHANCE OF OUTFLOW FROM DISTANT STORMS KICKING OFF A
STORM...MAINLY EAST OF THE LOWER COLORADO RIVER VALLEY. FOR SUNDAY
AND MONDAY...THE MODELS AGREE ON THE IDEA OF A SLOW WARMING OF THE
BOUNDARY LAYER TO REDUCE THE CAP BUT NO INCREASE IN MOISTURE...EVEN
DECREASING A BIT. SO SLIGHT CHANCES CONTINUE. ONE DIFFERENCE MIGHT
BE FOR MONDAY AS AN ANTICYCLONE BECOMES CENTERED OVER SOUTHERN
NEVADA LEADING TO NORTHEASTERLY STEERING FLOW...PER GFS...WHICH
COULD AID THE ADVECTION OF MOGOLLON RIM STORMS INTO OUR HIGHER
TERRAIN ZONE EAST OF PHOENIX. THE PRESSURE GRADIENT CONTINUES SUNDAY
FOR MORE BREEZINESS BEFORE WEAKENING MONDAY. MEANWHILE...HURRICANE
ODILE CURRENTLY SEVERAL HUNDRED MILES SOUTH-SOUTHEAST OF THE
SOUTHERN TIP OF BAJA IS FORECAST TO MOVE NORTHWESTWARD WITH THE EYE
GETTING FAIRLY CLOSE TO CABO SAN LUCAS LATE SUNDAY NIGHT/EARLY
MONDAY MORNING.
TUESDAY THROUGH SATURDAY...
MODELS INDICATE SOMETHING OF A GULF SURGE...MOST LIKELY DRIVEN BY
HURRICANE ODILE...MOVING INTO OUR FORECAST AREA BY TUESDAY. POPS GO
UP A BIT DUE TO INCREASED MOISTURE AND GREATER LIKELIHOOD OF
MOUNTAIN STORMS BUT THERE MAY BE SOME BOUNDARY LAYER COOLING WHICH
HURTS INSTABILITY OVER THE LOWER ELEVATIONS. 12Z GFS AND ECMWF BEGIN
DIVERGING MORE NOTICEABLY IN THEIR POSITIONING OF ODILE AS WELL AS
THE ANTICYCLONE TO THE NORTH AND THE NORTHEAST PACIFIC TROUGH. THE
ECMWF IS A BIT MORE AMPLIFIED WITH THE FLOW AND HAS THE MID LATITUDE
WAVE A BIT FURTHER WEST WITH ODILE CLOSER TO THE BAJA COAST. IT
BRINGS REMNANTS OF ODILE INLAND BY FRIDAY. THE 12Z GFS TRACKS ODILE
FURTHER WEST. HOWEVER...THE GFS HAS A MORE DISTINCT SHORT WAVE
MOVING NORTHWARD INTO ARIZONA WEDNESDAY NIGHT AND THURSDAY BECAUSE
IT HAS THE ANTICYCLONE FURTHER EAST. THE NATIONAL HURRICANE CENTER
FORECAST IS CLOSER TO THE ECWMF POSITION. A QUICK LOOK AT THE 18Z
GFS SHOWS THAT IT NOW LOOKS A LOT MORE LIKE THE ECMWF. IN
SHORT...THEY BOTH ARE INDICATING THAT THE BEST CHANCES FOR STORMS
AND ASSOCIATED FLOODING POTENTIAL IS IN THE WEDNESDAY THROUGH FRIDAY
TIME FRAME. IT SHOULD BE NOTED THAT NEITHER MODEL HAS ESPECIALLY
IMPRESSIVE MODEL RUN TOTAL PRECIP ACCUMULATIONS CONSIDERING THE
ABUNDANT PRECIPITABLE WATER THAT WILL BE AVAILABLE. LIKEWISE WITH
THE WPC FORECASTS. FORECASTS REFLECT POPS THAT ARE SUBSTANTIALLY
ABOVE CLIMO ALONG WITH COOLER TEMPS. FAR TOO EARLY FOR FLASH FLOOD
WATCHES BUT WILL CONTINUE TO EVALUATE.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...AND SOUTHEAST
CALIFORNIA AND SOUTHWEST ARIZONA...INCLUDING KIPL AND KBLH...
THROUGH 20Z SUN...MOSTLY CLEAR SKIES AND LIGHT WIND UNDER 9 KNOTS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
MOISTURE WILL STEADILY INCREASE ACROSS THE AREA DURING THE WEEK WITH
A NOTEWORTHY INCREASE IN HUMIDITIES TAKING PLACE ON WEDNESDAY.
SHOWERS WILL INCREASE IN COVERAGE WEDNESDAY NIGHT THROUGH FRIDAY
WITH SOME AREAS POTENTIALLY LOOKING AT PERIODS OF HEAVY RAINFALL. AS
SUCH...AFTERNOON HUMIDITIES WILL REMAIN ELEVATED WITH GOOD TO
EXCELLENT RECOVERIES EXPECTED. WINDS SHOULD BE LIGHT DURING THE WEEK
OUTSIDE OF THUNDERSTORM INDUCED OUTFLOWS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...VASQUEZ/AJ
AVIATION...VASQUEZ
FIRE WEATHER...MEYERS/LEINS
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
934 PM MDT SAT SEP 13 2014
.UPDATE...
ISSUED AT 930 PM MDT SAT SEP 13 2014
AT 9 PM...TEMPERATURES ARE GENERALLY RUNNING A FEW DEGREES WARMER
THAN LAST NIGHT...EXCEPT AROUND 10 DEGREES WARMER ACROSS THE
NORTH. A WEAK DISTURBANCE WITH SOME MID CLOUDS IS TRACKING INTO
EASTERN UTAH. THE HRRR MODEL IS PRODUCING SOME LIGHT SHOWERS
TONIGHT OVER THE LA SALS AND UNCOMPAHGRE PLATEAU...WHILE THE RAP
AND NAM12 DO NOT. NO POP MENTION IS IN THE FORECAST FOR NOW.
THE 00Z NAM HOLDS NO SURPRISES. MOISTURE IS VERY MARGINAL INTO THE
FOUR CORNERS GENERALLY STAYING IN THE 0.5INCH/NORTH TO 0.75/SOUTH
RANGE SUNDAY AND MONDAY PERHAPS INCREASING A BIT INTO TUESDAY. ANY
LATE DAY STORMS WILL FAVOR THE SOUTHERN MOUNTAINS AND WILL PRODUCE
MORE GUSTY WIND THAN SHOWERS.
TEMPERATURES RISE 2-5 DEGREES ON SUNDAY AND A FEW MORE DEGREES ON
MONDAY FOR SOME LATE SUMMER WARMTH.
MOISTURE FROM ODILE IS STILL ON TRACK FOR THURSDAY NIGHT-FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 235 PM MDT SAT SEP 13 2014
SOMEWHAT NON DESCRIPT WESTERLY FLOW WILL CONTINUE OVER THE REGION
DURING THIS PERIOD. PACIFIC MOISTURE ALOFT CURRENTLY OVER CA/NV
WILL BE OVER OUR AREA TOMORROW AND WITH A MODEST INCREASE IN PRECIP
WATER FROM THE SOUTH BACK INTO THE 0.50 TO 0.75 INCH RANGE...WILL
HAVE A LITTLE MORE COVERAGE OF DIURNALLY DRIVEN CONVECTION OVER
THE HIGHER TERRAIN. OVERNIGHT LOWS MODERATE OFF THE LOWS OF THE
PAST TWO NIGHTS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 235 PM MDT SAT SEP 13 2014
EXPECT BASICALLY THE SAME WEATHER CONDITIONS MONDAY AS SUNDAY WITH
LITTLE CHANGE IN THE OVERALL PATTERN. HOWEVER...WITH AMPLIFICATION
OF UPPER LEVEL RIDGE OVER UT TUESDAY THROUGH WEDNESDAY SHOULD SEE
RELATIVELY DRIER DAYS WITH UPPER LEVEL WINDS VEERING TO THE
NORTHWEST...INCREASED SUBSIDENCE AND LOWER PRECIP WATER VALUES
OVER THE REGION. THIS WILL ALSO MEAN TEMPS RUNNING 3 TO 8 DEGREES
ABOVE NORMAL.
THURSDAY THROUGH SATURDAY THE PATTERN BECOMES MORE INTERESTING BUT
ALSO LESS CERTAIN...ESPECIALLY HEADING INTO THE WEEKEND. ON
THURSDAY...THE REMNANTS OF HURRICANE ODILE WILL BE SOMEWHERE OFF
THE NORTH CENTRAL COAST OF BAJA CALIFORNIA WHILE AN UPPER LEVEL
TROUGH DIGS DOWN THE WEST COAST. IT APPEARS THE UPPER LEVEL RIDGE
INITIALLY OVER UT WEDNESDAY WILL BE OVER CO ON THURSDAY AND SHOULD
HOLD COVERAGE OF PRECIP AT BAY...WITH BEST SURGE OF TROPICAL
MOISTURE FROM THE VICINITY OF ODILE BEING PULLED NORTH ACROSS THE
GREAT BASIN. THERE IS AGREEMENT IN TRANSLATING THIS PLUME EASTWARD
OVER OUR AREA FRIDAY...SO HAVE RAISED POPS OVER THE ENSEMBLE BLEND
FOR THIS PERIOD. THEN THE MODELS DIVERGE. THE GFS SHOWS NORTHERN
STREAM TROUGH LEAVING ODILE BEHIND IN THE PACIFIC AND CLEARING THE
ROCKIES BY SATURDAY MORNING...USHERING IN DRIER NW FLOW FOR
SATURDAY. THE 12Z ECMWF CUTS OFF AN UPPER LEVEL LOW OFF THE CA
COAST FRI NIGHT...ABSORBS THE MOISTURE FROM ODILE AND KEEPS OUR
REGION IN A MOIST...UNSETTLED SOUTHWESTERLY FLOW PATTERN THROUGH
SUNDAY. CONSENSUS RIGHT NOW IS TO GO WITH A BLEND OF THE GFS AND
ECMWF ENSEMBLE SOLUTIONS WHICH FAVORS THE UPPER LEVEL TROUGH
PASSAGE FRIDAY NIGHT AND A DRIER PATTERN FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 930 PM MDT SAT SEP 13 2014
VFR CONDITIONS THROUGH THE PERIOD. WINDS WILL FOLLOW NORMAL THE
DIURNAL CYCLE. ISOLATED SHRA OR TSRA ARE POSSIBLE OVER THE
SOUTHERN MOUNTAINS SUNDAY AFTERNOON. THE ONLY IMPACT MAY BE GUSTY
ERRATIC OUTFLOW WINDS AT KDRO KTEX KMTJ AFTER 21Z.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JOE
SHORT TERM...BEN
LONG TERM...BEN
AVIATION...JOE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
303 PM MDT FRI SEP 12 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 242 PM MDT FRI SEP 12 2014
WIDESPREAD LOW CLOUDS CONTINUE TO COVER THE SERN CO PLAINS THIS
AFTERNOON...WITH TEMPS IN THE 40S. THE REST OF THE FORECAST AREA
HAS HAD MOSTLY SUNNY SKIES...WITH SOME CONVECTIVE CLOUDS DEVELOPING
OVER THE SRN MTNS AND SAN LUIS VALLEY. THERE CONTINUES TO BE SOME
SPOTTY LIGHT DRIZZLE IN LOCATIONS NR THE ERN MTNS. THE NAM HAS WAY
OVERDONE THE PCPN OVR THE SERN PLAINS FOR TODAY...WITH THE HRRR
BEING MORE REASONABLE. FOR THIS EVENING AND OVERNIGHT THE NAM
PRINTS OUT SOME ISOLD PCPN OVR THE SRN CO MTNS. THE HRRR IS DRY FOR
THIS EVENING. IT IS POSSIBLE THAT A FEW SHOWERS COULD DEVELOP FOR
THE EVENING HOURS...BUT FOR NOW WL LEAVE SILENT POPS IN THE
FORECAST. THE NAM AND HRRR ARE STILL SHOWING A DECREASE IN LOW LEVEL
CLOUD COVER LATER THIS AFTERNOON AND EARLY THIS EVENING...BUT NOT
SEEING ANY EVIDENCE OF THIS IN THE SATELLITE IMAGES YET. BOTH MODELS
THEN SHOW THE POTENTIAL FOR LOW CLOUD REFORMING OVR PORTIONS OF THE
PLAINS BY LATE EVENING. OVERNIGHT LOW TEMPS ARE EXPECTED TO BE IN
THE UPPER 30S TO LOWER 40S OVR THE SERN PLAINS...THE COLDEST AREAS
LOOK TO BE NORTHERN PORTIONS OF PUEBLO COUNTY...EL PASO AND CROWLEY
COUNTIES. LOWS IN THESE LOCATIONS LOOK LIKE THEY WL BE IN THE LOWER
30S. HAVE DECIDED TO ISSUE A FROST ADVISORY FOR THESE COUNTIES JUST
IN CASE THERE ARE POCKETS OF FROST.
MODELS ARE INDICATING THAT THE LOW CLOUDS SHOULD DISSIPATE BY LATE
MORNING ON SATURDAY WITH A GOOD WARM UP IN STORE. HIGHS ON SAT OVR
THE SERN PLAINS SHOULD BE IN THE 70S...WITH MID TO UPPER 70S IN THE
SAN LUIS VALLEY. GENERALLY DRY WESTERLY FLOW ALOFT IS EXPECTED OVR
THE FORECAST AREA. THE NAM AGAIN PRINTS OUT SOME LIGHT PCPN OVR THE
SRN CO MTNS AND SAN LUIS VALLEY SAT AFTERNOON...SO WL LEAVE SOME
ISOLD POPS IN THE FORECAST FOR THE SW MTNS AND THE SANGRES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 242 PM MDT FRI SEP 12 2014
MODELS IN GOOD AGREEMENT THROUGH THE EXTENDED PERIOD WITH SMALL
ENSEMBLE SPREADS AND HIGHER FORECAST CONFIDENCE.
SATURDAY NIGHT THROUGH SUNDAY NIGHT...FLAT ZONAL WESTERLY FLOW
WILL PERSIST ACROSS COLORADO THROUGH THIS PERIOD AS AN UPPER RIDGE
BEGINS TO BUILD ALONG THE WEST COAST AND SHORTWAVE TROUGH DROPS
SOUTH OUT OF CANADA INTO THE NORTHERN PLAINS. EXPECT ISOLATED
SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS ON SATURDAY EVENING
TO DISSIPATE AROUND SUNDOWN WITH LOSS OF DAYTIME INSTABILITY.
OVERNIGHT LOWS WILL FALL INTO THE MID TO UPPER 40S FOR MUCH OF THE
REGION. A WEAK DISTURBANCE EMBEDDED IN THE WESTERLY FLOW ALOFT
WILL MOVE ACROSS THE STATE ON SUNDAY AFTERNOON. ANOTHER ROUND OF
ISOLATED TO SCATTERED MOUNTAIN SHOWERS AND THUNDERSTORMS ARE
EXPECTED...WHICH SHOULD DISSIPATE ON SUNDAY EVENING. HIGHS SUNDAY
WILL REACH INTO THE 80S FOR THE LOWER ELEVATIONS.
MONDAY AND MONDAY NIGHT...MODELS IN GOOD AGREEMENT WITH A STRONG
COLD FRONT DROPPING SOUTH ACROSS THE EASTERN PLAINS ON MONDAY
MORNING. THE NAM IS THE FASTEST SOLUTION...WITH IT CLEARING SOUTH
INTO NEW MEXICO BY 12Z...WHILE THE ECMWF AND GFS ARE ABOUT 6 HOURS
SLOWER. FEEL THAT A BIT FASTER SOLUTIONS WILL LIKELY PLAY OUT AND
FOLLOWED THE NAM FRONTAL PROGRESSION. EXPECT LOW LEVEL FLOW TO
TURN EASTERLY AND USHER IN MUCH COOLER AIR INTO THE PLAINS.
UPGLIDE AND MOISTURE BEHIND THE FRONT WILL LIKELY LEAD TO LIGHT
RAIN FOR THE PLAINS THROUGH MONDAY AFTERNOON. WARMER TEMPERATURES
AND GREATER INSTABILITY WILL EXIST OVER THE MOUNTAIN AREAS MONDAY
AFTERNOON AND SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED.
MODELS IN AGREEMENT WITH THE LIGHT RAIN COMING TO AN END FOR THE
PLAINS FROM NORTH TO SOUTH THROUGH THE AFTERNOON HOURS. EXPECT
THUNDERSTORMS OVER THE MOUNTAINS TO DISSIPATE AFTER SUNSET.
TEMPERATURES WILL BE MUCH COOLER BEHIND THE FRONT WITH THE PLAINS
LIKELY ONLY SEEING 60S FOR HIGHS.
TUESDAY THROUGH FRIDAY...THE UPPER PATTERN WILL BECOME AMPLIFIED
ACROSS THE CONUS WITH HIGH PRESSURE BUILDING OVER THE WEST AND A
TROUGH OVER THE EASTERN STATES. THIS WILL PUT SOUTHERN COLORADO
UNDER BROAD NORTHWEST FLOW. EXPECT GENERALLY DRY CONDITIONS ACROSS
THE REGION WITH DAILY AFTERNOON AND EVENING MOUNTAIN CONVECTION
POSSIBLE. TEMPERATURES WILL BE QUICK TO WARM UP WITH 80S FOR THE
LOWER ELEVATIONS THROUGH THE MIDDLE OF THE WEEK.
BY FRIDAY MODELS ARE BRINGING A PIECE OF ENERGY FROM TROPICAL
STORM ODILE WHICH IS FORECAST TO BE OFF THE NORTHERN BAJA COAST BY
FRIDAY. IF THIS DISTURBANCE AND MOISTURE DOES MATERIALIZE...THERE
WILL BE MUCH BETTER CHANCES FOR PRECIPITATION...ESPECIALLY ALONG
THE CONTINENTAL DIVIDE...BY FRIDAY. THIS WILL NEED TO BE
MONITORED. MOZLEY
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 242 PM MDT FRI SEP 12 2014
KPUB WL HAVE LOW VFR CIGS TONIGHT...POSSIBLY BEING MVFR AT TIMES.
CLOUD WILL DECREASE SAT MORNING WITH VFR CONDITIONS EXPECTED. KCOS
WL HAVE MVFR OR LOW VFR CONDITIONS TONIGHT. CLOUDS WILL DECREASE BY
LATE SAT MORNING. KALS IS EXPECTED TO HAVE VFR CONDITIONS TONIGHT
THROUGH SATURDAY.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 1 AM TO 8 AM MDT SATURDAY FOR COZ084>086-089.
&&
$$
SHORT TERM...28
LONG TERM...MOZLEY
AVIATION...28
AREA FORECAST DISCUSSION
NWS MIAMI FL
927 PM EDT SAT SEP 13 2014
.UPDATE...
DEEP TROPICAL FLOW REMAINS IN PLACE ACROSS SOUTH FLORIDA AS
EVIDENCED ON THE 00Z MFL SOUNDING THIS EVENING. THE PWAT IS JUST
OVER TWO INCHES WHICH IS SLIGHTLY ABOVE THE AVERAGE FOR MID
SEPTEMBER. SATELLITE AND RADAR SIGNATURES ALSO REFLECT THIS WITH
AMPLE SHOWER ACTIVITY WITH SOME EMBEDDED TSRA. SO NO CHANGES ARE
PLANNED AT THIS TIME AND WILL KEEP HIGH END CHANCES FOR RAIN
THROUGH THE NIGHT.
KOB
&&
.PREV DISCUSSION... /ISSUED 812 PM EDT SAT SEP 13 2014/
AVIATION...
EXTENSIVE CLUSTER OF SHOWERS AND THUNDERSTORMS THAT EXITED CUBA
THIS AFTERNOON IS PROGRESSING INTO MIAMI-DADE COUNTY AT TAF
ISSUANCE TIME. TEMPO TSRA GROUPS FOR ALL MIAMI-DADE TERMINALS
THROUGH 2Z...WITH VCTS AREAWIDE UNTIL 6Z. LOCALLY GUSTY WINDS...35
KNOTS CANT BE RULED OUT...AND SIGNIFICANT RESTRICTIONS POSSIBLE
WITH THIS ACTIVITY. BY MIDNIGHT...UNCERTAIN ON SHWR/TSTM COVERAGE
AS GUIDANCES SUGGESTS CLIMATOLOGICALLY UNUSUAL OCCURRENCE OF
SHOWERS/TSTMS INTO SUNDAY MORNING. FOR NOW WILL HANDLE WITH
VCSH...ALTHOUGH PERIODS OF THUNDER QUITE POSSIBLE...ESPECIALLY
CONSIDERING LAST NIGHT HAD SIMILAR ACTIVITY. THUNDERSTORMS SHOULD
REINVIGORATE BY LATE MORNING. AWAY FROM CONVECTION...ESE WINDS 5
KTS OVERNIGHT...10-15 KTS SUNDAY.
PREV DISCUSSION... /ISSUED 348 PM EDT SAT SEP 13 2014/
DISCUSSION...
THE LATEST CONSENSUS OF THE MODEL GUIDANCE...BOTH THE GLOBAL
MODELS AND THE LATEST HRRR RUN...INDICATE THE POTENTIAL FOR
SHOWERS AND THUNDERSTORMS TO FORM ACROSS THE FLORIDA STRAITS THIS
EVENING AND AFFECT THE SOUTHERN PORTIONS OF SOUTH FLORIDA AND
ADJACENT WATERS LATER THIS EVENING AND POSSIBLY CONTINUING INTO
THE EARLY MORNING HOURS ON SUNDAY. RECENT SATELLITE IMAGERY AND
RADAR RETURNS INDICATE THIS PROCESS IS ALREADY UNDERWAY WITH BANDS
OF SHOWERS AND THUNDERSTORMS OBSERVED ACROSS THE FLORIDA STRAITS.
OVER NIGHT AND INTO SUNDAY...A BROAD AREA OF SURFACE LOW PRESSURE
ACROSS THE EASTERN GULF WILL CONTINUE TO TRACK WESTWARD INTO THE
CENTRAL GULF. THE MORE RECENT GUIDANCE HAS CONSISTENTLY BEEN
INDICATING THAT DEEP TROPICAL MOISTURE WILL CONTINUE TO LINGER
ACROSS SOUTH FLORIDA AND ADJACENT WATERS WITH LOW LEVEL MASS AND
MOISTURE CONVERGENCE CONTINUING ACROSS THE REGION INTO SUNDAY
MORNING. IN ADDITION THE UPPER LEVEL WINDS COULD BE FAVORABLE FOR
SPEED DIVERGENCE DURING THE AFTERNOON HOURS. DAY TIME HEATING AND
WITH THE LINGERING DEEP MOISTURE WILL ALLOW FOR AFTERNOON
CONVECTION ON SUNDAY WITH THE GREATEST COVERAGE OF SHOWERS AND
THUNDERSTORMS EXPECTED INLAND AND WEST.
FOR MONDAY AND TUESDAY...SOME RELATIVELY DRIER AIR IS FORECAST TO
ENTER THE REGION ALTHOUGH THE GUIDANCE CONSENSUS INDICATES THAT
LINGERING MOISTURE COULD BE SUFFICIENT FOR AFTERNOON SHOWERS AND
THUNDERSTORMS...MAINLY OVER THE THE PENINSULA. THE EXTENDED
GUIDANCE CONTINUES TO SUGGEST THAT LATE NEXT WEEK DEEP MOISTURE
COULD EXTEND FROM THE YUCATAN PENINSULA NORTHEASTWARD ACROSS SOUTH
FLORIDA AND INTO THE WESTERN ATLANTIC WITH A LARGE AMPLITUDE UPPER
LEVEL TROUGH DEEPENING INTO THE CENTRAL GULF. THIS PATTERN IS
FORECAST TO LINGER INTO NEXT WEEKEND WITH THE POTENTIAL FOR
WIDESPREAD LOCAL CONVECTION.
MARINE...
MAINLY EASTERLY WINDS ARE FORECAST TO BE IN THE 10 TO 15 KNOT
RANGE ACROSS THE REGIONAL WATERS TONIGHT THROUGH SUNDAY THEN
SLOWLY DECREASING INTO EARLY NEXT WEEK WHILE REMAINING EASTERLY.
REGIONAL SEAS ARE FORECAST TO BE MAINLY AROUND 2 FEET OR LESS THE
REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 76 86 76 87 / 40 60 20 50
FORT LAUDERDALE 77 88 79 88 / 50 50 20 50
MIAMI 77 87 78 88 / 50 50 20 50
NAPLES 75 87 76 89 / 40 60 20 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
812 PM EDT SAT SEP 13 2014
.AVIATION...
EXTENSIVE CLUSTER OF SHOWERS AND THUNDERSTORMS THAT EXITED CUBA
THIS AFTERNOON IS PROGRESSING INTO MIAMI-DADE COUNTY AT TAF
ISSUANCE TIME. TEMPO TSRA GROUPS FOR ALL MIAMI-DADE TERMINALS
THROUGH 2Z...WITH VCTS AREAWIDE UNTIL 6Z. LOCALLY GUSTY WINDS...35
KNOTS CANT BE RULED OUT...AND SIGNIFICANT RESTRICTIONS POSSIBLE
WITH THIS ACTIVITY. BY MIDNIGHT...UNCERTAIN ON SHWR/TSTM COVERAGE
AS GUIDANCES SUGGESTS CLIMATOLOGICALLY UNUSUAL OCCURRENCE OF
SHOWERS/TSTMS INTO SUNDAY MORNING. FOR NOW WILL HANDLE WITH
VCSH...ALTHOUGH PERIODS OF THUNDER QUITE POSSIBLE...ESPECIALLY
CONSIDERING LAST NIGHT HAD SIMILAR ACTIVITY. THUNDERSTORMS SHOULD
REINVIGORATE BY LATE MORNING. AWAY FROM CONVECTION...ESE WINDS 5
KTS OVERNIGHT...10-15 KTS SUNDAY.
&&
.PREV DISCUSSION... /ISSUED 348 PM EDT SAT SEP 13 2014/
DISCUSSION...
THE LATEST CONSENSUS OF THE MODEL GUIDANCE...BOTH THE GLOBAL
MODELS AND THE LATEST HRRR RUN...INDICATE THE POTENTIAL FOR
SHOWERS AND THUNDERSTORMS TO FORM ACROSS THE FLORIDA STRAITS THIS
EVENING AND AFFECT THE SOUTHERN PORTIONS OF SOUTH FLORIDA AND
ADJACENT WATERS LATER THIS EVENING AND POSSIBLY CONTINUING INTO
THE EARLY MORNING HOURS ON SUNDAY. RECENT SATELLITE IMAGERY AND
RADAR RETURNS INDICATE THIS PROCESS IS ALREADY UNDERWAY WITH BANDS
OF SHOWERS AND THUNDERSTORMS OBSERVED ACROSS THE FLORIDA STRAITS.
OVER NIGHT AND INTO SUNDAY...A BROAD AREA OF SURFACE LOW PRESSURE
ACROSS THE EASTERN GULF WILL CONTINUE TO TRACK WESTWARD INTO THE
CENTRAL GULF. THE MORE RECENT GUIDANCE HAS CONSISTENTLY BEEN
INDICATING THAT DEEP TROPICAL MOISTURE WILL CONTINUE TO LINGER
ACROSS SOUTH FLORIDA AND ADJACENT WATERS WITH LOW LEVEL MASS AND
MOISTURE CONVERGENCE CONTINUING ACROSS THE REGION INTO SUNDAY
MORNING. IN ADDITION THE UPPER LEVEL WINDS COULD BE FAVORABLE FOR
SPEED DIVERGENCE DURING THE AFTERNOON HOURS. DAY TIME HEATING AND
WITH THE LINGERING DEEP MOISTURE WILL ALLOW FOR AFTERNOON
CONVECTION ON SUNDAY WITH THE GREATEST COVERAGE OF SHOWERS AND
THUNDERSTORMS EXPECTED INLAND AND WEST.
FOR MONDAY AND TUESDAY...SOME RELATIVELY DRIER AIR IS FORECAST TO
ENTER THE REGION ALTHOUGH THE GUIDANCE CONSENSUS INDICATES THAT
LINGERING MOISTURE COULD BE SUFFICIENT FOR AFTERNOON SHOWERS AND
THUNDERSTORMS...MAINLY OVER THE THE PENINSULA. THE EXTENDED
GUIDANCE CONTINUES TO SUGGEST THAT LATE NEXT WEEK DEEP MOISTURE
COULD EXTEND FROM THE YUCATAN PENINSULA NORTHEASTWARD ACROSS SOUTH
FLORIDA AND INTO THE WESTERN ATLANTIC WITH A LARGE AMPLITUDE UPPER
LEVEL TROUGH DEEPENING INTO THE CENTRAL GULF. THIS PATTERN IS
FORECAST TO LINGER INTO NEXT WEEKEND WITH THE POTENTIAL FOR
WIDESPREAD LOCAL CONVECTION.
MARINE...
MAINLY EASTERLY WINDS ARE FORECAST TO BE IN THE 10 TO 15 KNOT
RANGE ACROSS THE REGIONAL WATERS TONIGHT THROUGH SUNDAY THEN
SLOWLY DECREASING INTO EARLY NEXT WEEK WHILE REMAINING EASTERLY.
REGIONAL SEAS ARE FORECAST TO BE MAINLY AROUND 2 FEET OR LESS THE
REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 76 86 76 87 / 40 60 20 50
FORT LAUDERDALE 77 88 79 88 / 50 50 20 50
MIAMI 77 87 78 88 / 50 50 20 50
NAPLES 75 87 76 89 / 40 60 20 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...30/KOB
LONG TERM....60/BD
AVIATION...23/SK
AREA FORECAST DISCUSSION...CORRECTED
NWS MIAMI FL
147 PM EDT FRI SEP 12 2014
.AVIATION...
AREA OF LOW PRESSURE MOVING WEST SOUTHWEST ACROSS SOUTH CENTRAL
FLORIDA, IS RESPONSIBLE FOR INCREASING SHOWERS AND THUNDERSTORMS
NEAR KAPF AT THIS HOUR. SOME BRIEF IFR CONDS ARE POSSIBLE, BUT
TRAINING STORMS COULD CREATE MORE PERSISTENT IFR CONDS THERE IN
THE NEXT FEW HOURS. SHOWERS AND STORMS ACROSS THE ATLANTIC WATERS
ARE HAVING A DIFFICULT TIME CROSSING THE BEACHES, ESPECIALLY WITH
CLOUDS BREAKING. HOWEVER, INSOLATION THIS AFTERNOON MAY ALLOW
STORMS TO DEVELOP NEAR THE TAF SITES EVENTUALLY AS INSTABILITY
INCREASES. WITH EASTERLY FLOW CONTINUING TONIGHT, VCSH MAY BE
NEEDED FOR MUCH OF THE NIGHT WITH SHOWERS ARRIVING OVERNIGHT FROM
THE ATLANTIC WATERS.
&&
.PREV DISCUSSION... /ISSUED 833 AM EDT FRI SEP 12 2014/
AVIATION...
TROPICAL RAIN SHOWERS WITH EMBEDDED THUNDER ARE MOVING SSW THROUGH
SOUTH FLORIDA. THE HEAVIEST RAIN IS MOSTLY WEST OF THE TERMINALS
AT THIS HOUR, WITH LINES OF SHOWERS WITH SOME STORMS MOVING NORTH
ACROSS THE ATLANTIC WATERS DUE TO FLOW AROUND LOW PRESSURE. AS
THE AREA OF LOW PRESSURE MOVES SW, WHICH IS NOW JUST SW OF KPBI,
SHOWERS AND STORMS WILL LIKELY REDEVELOP ALONG THE COAST THIS
AFTERNOON ESPECIALLY WITH BREAKS IN THE CLOUDINESS ADDING TO THE
INSTABILITY. ALTHOUGH POPS ARE HIGH, PINPOINTING THUNDER IS MORE
TRICKY, SO MAY NEED TO WAIT A WHILE BEFORE INSERTING TEMPO GROUPS
FOR THIS AFTERNOON. DESPITE ABUNDANT MOISTURE, CONVERGENCE AND
NEARBY H5 DISTURBANCE, HRRR IS RATHER DRY THIS AFTERNOON, WHICH
REDUCES CONFIDENCE. 1K FT CIG THIS EARLY MORNING AT KPBI MAY
BRIEFLY FALL TO IFR, BEFORE IMPROVEMENT LATER THIS MORNING.
PREV DISCUSSION... /ISSUED 445 AM EDT FRI SEP 12 2014/
DISCUSSION...
VERY HEAVY RAIN IS FALLING ACROSS INLAND PALM BEACH COUNTY EARLY
THIS MORNING. THE AREA OF LOW PRESSURE MAY HAVE REDEVELOPED NEAR
THE COAST JUST OFF OF PALM BEACH COUNTY. AN MCV FEATURE DEVELOPED
OVER EASTERN PALM BEACH COUNTY VERY EARLY THIS MORNING TO THE
SOUTHWEST OF THE AREA OF LOW PRESSURE...WITH EXPANDING CLOUD TOPS
AS COLD AS -75C. THIS FEATURE HAS BEEN MOVING SLOWLY TOWARDS THE
WEST SOUTHWEST...WITH 2-3 INCH PER HOUR RAINFALL RATES. MORE
RECENTLY...THE HEAVIEST RAIN HAS BEEN WEAKENING IN INTENSITY AND
CLOUD TOPS HAVE BEGUN TO WARM. THE NORTH TO NORTHEASTERLY SHEAR
WILL PUSH THE HEAVIEST RAIN TO THE SOUTHWEST OF THE AREA OF LOW
PRESSURE...AND THE HEAVY RAIN MAY MOVES TOWARDS THE NAPLES REGION
LATER THIS MORNING IF IT HOLDS TOGETHER. LOCALLY HEAVY RAIN AND
FLOODING IS POSSIBLE...AND AN ISOLATED TORNADO CANNOT BE RULED
OUT.
FOR THE EAST COAST...POPS MAY BE A LITTLE TOO HIGH DUE TO THE
CLOUD COVER AND STORMS BEING PUSHED TO THE SOUTHWEST OF THE AREA
OF LOW PRESSURE. HOWEVER...STORMS COULD REDEVELOP AND FOCUS OVER
THE EAST COAST THIS AFTERNOON...AND MOST AREAS WILL SEE AT LEAST
LIGHT RAIN THIS MORNING. SO KEPT LIKELY POPS ACROSS THE
BOARD...BUT AMOUNTS ARE UNCERTAIN AT THIS TIME. FOR
TEMPERATURES...MOST LOCATIONS WILL REACH THE LOW/MID 80S...WITH
RAIN COOLED LOCATIONS REMAINING IN THE 70S.
THE AREA OF LOW PRESSURE/MCV WILL MOVE WEST SOUTHWEST ACROSS THE
REGION THROUGH THE DAY...AND EXIT INTO THE GULF OF MEXICO TONIGHT.
THE MODELS STILL DIFFER ON THE LOCATION OF THE LOW AND RAINFALL
CHANCES ACROSS THE REGION OVERNIGHT. THE ECMWF IS MUCH WETTER THAN
THE GFS...KEEPING DEEPER MOISTURE AND MORE SOUTHERLY FLOW ACROSS
SOUTH FLORIDA. KEPT WITH THE WETTER SOLUTION FOR THE SOUTHERN
PORTIONS OF THE REGION AND THE COASTAL AREAS OVERNIGHT.
SATURDAY...RIDGE OF HIGH PRESSURE WILL BUILD OVER THE WESTERN
ATLANTIC TO THE NORTHEAST OF THE REGION ON SATURDAY. THE AREA OF
LOW PRESSURE WILL CONTINUE WESTWARD INTO THE SOUTH CENTRAL GULF.
SOUTHEAST FLOW AND DEEP MOISTURE IS FORECAST TO CONTINUE...AND
RAIN CHANCES WILL CONTINUE IN THE 50-70 PERCENT RANGE...HIGHEST
ACROSS THE GULF COAST.
SUNDAY...DIFFERENCES STILL REMAIN IN THE MODELS ON SUNDAY. THE GFS
IS MUCH FASTER WITH THE AREA OF LOW PRESSURE OVER THE GULF.
THUS...THE REGION WOULD RETURN TO A MORE TYPICAL EASTERLY FLOW
REGIME...WITH SCATTERED STORMS DEVELOPING INLAND OF THE EAST COAST
AND THEN PUSHING TOWARDS THE GULF COAST IN THE AFTERNOON. THE
ECMWF IS MORE THAN 2 DEGREES TO THE EAST. THE ECMWF KEEPS THE
MOISTURE AXIS ACROSS SOUTH FLORIDA FROM THE AREA OF LOW PRESSURE
OVER THE GULF...WITH A LIGHT SOUTHERLY FLOW ACROSS THE REGION.
RAIN CHANCES WOULD THEN REMAIN VERY HIGH ACROSS MOST OF THE
REGION. FOR NOW KEPT SCATTERED POPS ALONG THE EAST COAST AND
LIKELY ACROSS THE INTERIOR AND GULF.
EARLY TO MIDDLE OF NEXT WEEK...AN UPPER TROUGH IS FORECAST TO DIG
ACROSS THE EASTERN CONUS AND INTO THE SOUTHEAST THE EARLY TO MIDDLE
PART OF THE WEEK. THE ECMWF IS DEEPER WITH THE TROUGH AND PUSHES A
COLD FRONT INTO SOUTHERN GEORGIA BY THE MIDDLE OF THE WEEK. THE
ECMWF PUSHES THE RIDGE AXIS OVER THE REGION ON MONDAY AND THEN
SOUTH OF THE REGION BY THE MIDDLE OF THE WEEK...WITH WEST TO
SOUTHWESTERLY FLOW. THIS WOULD FAVOR HIGHER RAIN CHANCES FOR THE
EAST AND NORTHEAST METRO AREAS.
AVIATION...
A WEAK AREA OF LOW PRESSURE CENTERED AROUND THE PALM BEACH COAST
WILL CONTINUE WESTWARD TOWARD THE GULF COAST THROUGH THE PERIOD.
PERIODS OF HEAVY RAINFALL WILL REMAIN IN THE FORECAST ACROSS THE
SOUTH FLORIDA REGION THROUGH THIS TIME. WINDS OVER THE EAST COAST
TAF SITES WILL SHIFT TO THE SOUTHEAST SOMETIME THROUGH THE
AFTERNOON HOURS TODAY AS THE LOW CONTINUES WESTWARD. WINDS AT
NAPLES WILL REMAIN LIGHT AND VARIABLE THROUGH THE PERIOD AS
UNCERTAINTY REGARDING THE EXACT TRACK OF THE LOW RELATIVE TO THE
APF TERMINAL REMAINS HIGH AT THIS TIME. AS THE LOW SHIFTS WESTWARD
OFF OF THE NAPLES COAST...LIGHT TO MODERATE SE WINDS WILL RETURN
ACROSS THE AREA. /85
MARINE...
A WEAK AREA OF LOW PRESSURE NEAR THE PALM BEACH COAST EARLY THIS
MORNING WILL MOVE ACROSS SOUTH FLORIDA TODAY...AND THEN INTO THE
REGIONAL GULF WATERS TONIGHT. THERE COULD BE SOME WATERSPOUTS
TODAY, ESPECIALLY ACROSS THE ATLANTIC WATERS, WITH CIRCULATION
AROUND THE AREA OF LOW PRESSURE, WHICH WILL BE MOVING SW THROUGH
SOUTH FLORIDA TODAY. RAIN CHANCES WILL REMAIN HIGH OVER THE
ATLANTIC AND GULF WATERS TODAY INTO THE WEEKEND. THE NHC IS
MONITORING THIS AREA OF LOW PRESSURE...AND THERE IS A MEDIUM
CHANCE OF DEVELOPMENT ONCE IT MOVES INTO THE GULF OF MEXICO. THIS
COULD IMPACT THE GULF FORECAST OVER THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 76 88 76 89 / 40 50 40 50
FORT LAUDERDALE 77 89 77 90 / 40 60 40 50
MIAMI 77 89 77 90 / 40 60 40 50
NAPLES 73 89 74 91 / 50 70 30 60
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...60/BD
LONG TERM....60/BD
AVIATION...21/KM
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1000 AM EDT FRI SEP 12 2014
.DISCUSSION...
.UPDATE...WEAK SFC LOW MOVED ONSHORE EARLY THIS MORNING WITH A
1012.3 MB SFC PRESSURE READING AT WEST PALM BEACH AT 5 AM. AT 9
AM...THE SFC LOW HAD MOVED INLAND SOUTH OF LAKE OKEECHOBEE AND
SHOULD CONTINUE TO MOVE SLOWLY W/WSW. A CONVERGENT BAND OF SCATTERED
SHOWERS HAD AFFECTED VOLUSIA COUNTY AROUND SUNRISE BUT THAT ACTIVITY
HAS RECENTLY DIMINISHED. MORNING CAPE SOUNDING AT 10Z INDICATED DEEP
MOISTURE WITH PRECIPITABLE WATER VALUE OF 2.15 WITH DEEP LAYER NE
FLOW IN THE MID TO UPPER LEVELS. UPSTREAM SOUNDING AT JAX WAS MUCH
DRIER WITH A PWAT OF 1.66 AND SUBSTANTIAL DRY LAYER ABOVE 600 MBS.
06Z GFS HAS THE LOW LVL CIRCULATION IN THE H9-H8 LAYER SHIFTING
WESTWARD TOWARD FT MYERS BY THIS EVENING WITH LOW TO MID LVL FLOW
BECOMING SE INTO THIS AFTERNOON ACROSS E CENTRAL FL. NORMALLY THIS
WOULD BE A FAVORABLE ENVIRONMENT ON THE ASCENDANT SIDE OF THE LOW
LVL CIRCULATION TO SEE A HIGH COVERAGE OF AFTERNOON STORMS WITH
ADEQUATE DEEP MOISTURE. A CLOSER LOOK AT GFS MODEL MEAN RH FIELDS
SHOWS DECREASING MOISTURE IN THE 700-300 MB LAYER ACROSS OUR SRN
AREAS THIS AFTERNOON AND HRRR INDICATES A LACK OF DEEP CONVECTION
DEVELOPING ACROSS MUCH E CENTRAL FL THIS AFTERNOON WITH MAINLY
SHOWER ACTIVITY. WILL STILL FAVOR SRN INTERIOR SECTIONS FOR HIGHEST
AFTERNOON SHOWERS/THUNDERSTORM CHANCES CLOSER TO THE SFC LOW
PRESSURE AREA AND WHERE LOW LVL CONVERGENCE SHOULD BE MAXIMIZED AS
DIFFUSE EAST COAST SEA BREEZE SHOULD MOVE INLAND LATE THIS AFTN.
HIGHS WILL AVERAGE IN THE UPPER 80S ALONG THE EAST COAST TO AROUND
90/LOWER 90S OVER THE INTERIOR.
&&
.AVIATION...
CHC FOR TSRA DEVELOPMENT LOWER THAN NORMAL FOR TERMINALS WITH HIGHER
CHANCE OF AFTERNOON CONVECTIVE COVERAGE SOUTH OF KISM TO AROUND KOBE
VCNTY AND MAINLY INLAND FROM SRN CSTL TERMINALS FROM KVRB-KSUA. VCSH
IN AT MOST TERMINALS INTO THIS AFTN WITH SCT SHRA AND ISOLATED TSRA
DEVELOPMENT ACROSS E CENTRAL FL INTO MID-LATE AFTN AS SFC LOW PRES
AREA MOVES WESTWARD ACROSS THE SRN PENINSULA. BRIEF MVFR/CIGS VSBY
MAY OCCUR WITH CONVECTION THIS AFTERNOON...MAINLY AFT 18Z.
&&
.MARINE...
E-SE WINDS TO 10-15 KNOTS WILL VEER TO THE SE BY LATE AFTERNOON. SEAS
MAINLY 3 FT NEARSHORE TO 3-4 FT OFFSHORE TODAY WITH SHORTER PERIOD
WIND WAVE THE PRIMARY COMPONENT.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
VOLKMER/SEDLOCK
AREA FORECAST DISCUSSION
NWS MIAMI FL
833 AM EDT FRI SEP 12 2014
.AVIATION...
TROPICAL RAIN SHOWERS WITH EMBEDDED THUNDER ARE MOVING SSW THROUGH
SOUTH FLORIDA. THE HEAVIEST RAIN IS MOSTLY WEST OF THE TERMINALS
AT THIS HOUR, WITH LINES OF SHOWERS WITH SOME STORMS MOVING NORTH
ACROSS THE ATLANTIC WATERS DUE TO FLOW AROUND LOW PRESSURE. AS
THE AREA OF LOW PRESSURE MOVES SW, WHICH IS NOW JUST SW OF KPBI,
SHOWERS AND STORMS WILL LIKELY REDEVELOP ALONG THE COAST THIS
AFTERNOON ESPECIALLY WITH BREAKS IN THE CLOUDINESS ADDING TO THE
INSTABILITY. ALTHOUGH POPS ARE HIGH, PINPOINTING THUNDER IS MORE
TRICKY, SO MAY NEED TO WAIT A WHILE BEFORE INSERTING TEMPO GROUPS
FOR THIS AFTERNOON. DESPITE ABUNDANT MOISTURE, CONVERGENCE AND
NEARBY H5 DISTURBANCE, HRRR IS RATHER DRY THIS AFTERNOON, WHICH
REDUCES CONFIDENCE. 1K FT CIG THIS EARLY MORNING AT KPBI MAY
BRIEFLY FALL TO IFR, BEFORE IMPROVEMENT LATER THIS MORNING.
&&
.PREV DISCUSSION... /ISSUED 445 AM EDT FRI SEP 12 2014/
DISCUSSION...
VERY HEAVY RAIN IS FALLING ACROSS INLAND PALM BEACH COUNTY EARLY
THIS MORNING. THE AREA OF LOW PRESSURE MAY HAVE REDEVELOPED NEAR
THE COAST JUST OFF OF PALM BEACH COUNTY. AN MCV FEATURE DEVELOPED
OVER EASTERN PALM BEACH COUNTY VERY EARLY THIS MORNING TO THE
SOUTHWEST OF THE AREA OF LOW PRESSURE...WITH EXPANDING CLOUD TOPS
AS COLD AS -75C. THIS FEATURE HAS BEEN MOVING SLOWLY TOWARDS THE
WEST SOUTHWEST...WITH 2-3 INCH PER HOUR RAINFALL RATES. MORE
RECENTLY...THE HEAVIEST RAIN HAS BEEN WEAKENING IN INTENSITY AND
CLOUD TOPS HAVE BEGUN TO WARM. THE NORTH TO NORTHEASTERLY SHEAR
WILL PUSH THE HEAVIEST RAIN TO THE SOUTHWEST OF THE AREA OF LOW
PRESSURE...AND THE HEAVY RAIN MAY MOVES TOWARDS THE NAPLES REGION
LATER THIS MORNING IF IT HOLDS TOGETHER. LOCALLY HEAVY RAIN AND
FLOODING IS POSSIBLE...AND AN ISOLATED TORNADO CANNOT BE RULED
OUT.
FOR THE EAST COAST...POPS MAY BE A LITTLE TOO HIGH DUE TO THE
CLOUD COVER AND STORMS BEING PUSHED TO THE SOUTHWEST OF THE AREA
OF LOW PRESSURE. HOWEVER...STORMS COULD REDEVELOP AND FOCUS OVER
THE EAST COAST THIS AFTERNOON...AND MOST AREAS WILL SEE AT LEAST
LIGHT RAIN THIS MORNING. SO KEPT LIKELY POPS ACROSS THE
BOARD...BUT AMOUNTS ARE UNCERTAIN AT THIS TIME. FOR
TEMPERATURES...MOST LOCATIONS WILL REACH THE LOW/MID 80S...WITH
RAIN COOLED LOCATIONS REMAINING IN THE 70S.
THE AREA OF LOW PRESSURE/MCV WILL MOVE WEST SOUTHWEST ACROSS THE
REGION THROUGH THE DAY...AND EXIT INTO THE GULF OF MEXICO TONIGHT.
THE MODELS STILL DIFFER ON THE LOCATION OF THE LOW AND RAINFALL
CHANCES ACROSS THE REGION OVERNIGHT. THE ECMWF IS MUCH WETTER THAN
THE GFS...KEEPING DEEPER MOISTURE AND MORE SOUTHERLY FLOW ACROSS
SOUTH FLORIDA. KEPT WITH THE WETTER SOLUTION FOR THE SOUTHERN
PORTIONS OF THE REGION AND THE COASTAL AREAS OVERNIGHT.
SATURDAY...RIDGE OF HIGH PRESSURE WILL BUILD OVER THE WESTERN
ATLANTIC TO THE NORTHEAST OF THE REGION ON SATURDAY. THE AREA OF
LOW PRESSURE WILL CONTINUE WESTWARD INTO THE SOUTH CENTRAL GULF.
SOUTHEAST FLOW AND DEEP MOISTURE IS FORECAST TO CONTINUE...AND
RAIN CHANCES WILL CONTINUE IN THE 50-70 PERCENT RANGE...HIGHEST
ACROSS THE GULF COAST.
SUNDAY...DIFFERENCES STILL REMAIN IN THE MODELS ON SUNDAY. THE GFS
IS MUCH FASTER WITH THE AREA OF LOW PRESSURE OVER THE GULF.
THUS...THE REGION WOULD RETURN TO A MORE TYPICAL EASTERLY FLOW
REGIME...WITH SCATTERED STORMS DEVELOPING INLAND OF THE EAST COAST
AND THEN PUSHING TOWARDS THE GULF COAST IN THE AFTERNOON. THE
ECMWF IS MORE THAN 2 DEGREES TO THE EAST. THE ECMWF KEEPS THE
MOISTURE AXIS ACROSS SOUTH FLORIDA FROM THE AREA OF LOW PRESSURE
OVER THE GULF...WITH A LIGHT SOUTHERLY FLOW ACROSS THE REGION.
RAIN CHANCES WOULD THEN REMAIN VERY HIGH ACROSS MOST OF THE
REGION. FOR NOW KEPT SCATTERED POPS ALONG THE EAST COAST AND
LIKELY ACROSS THE INTERIOR AND GULF.
EARLY TO MIDDLE OF NEXT WEEK...AN UPPER TROUGH IS FORECAST TO DIG
ACROSS THE EASTERN CONUS AND INTO THE SOUTHEAST THE EARLY TO MIDDLE
PART OF THE WEEK. THE ECMWF IS DEEPER WITH THE TROUGH AND PUSHES A
COLD FRONT INTO SOUTHERN GEORGIA BY THE MIDDLE OF THE WEEK. THE
ECMWF PUSHES THE RIDGE AXIS OVER THE REGION ON MONDAY AND THEN
SOUTH OF THE REGION BY THE MIDDLE OF THE WEEK...WITH WEST TO
SOUTHWESTERLY FLOW. THIS WOULD FAVOR HIGHER RAIN CHANCES FOR THE
EAST AND NORTHEAST METRO AREAS.
AVIATION...
A WEAK AREA OF LOW PRESSURE CENTERED AROUND THE PALM BEACH COAST
WILL CONTINUE WESTWARD TOWARD THE GULF COAST THROUGH THE PERIOD.
PERIODS OF HEAVY RAINFALL WILL REMAIN IN THE FORECAST ACROSS THE
SOUTH FLORIDA REGION THROUGH THIS TIME. WINDS OVER THE EAST COAST
TAF SITES WILL SHIFT TO THE SOUTHEAST SOMETIME THROUGH THE
AFTERNOON HOURS TODAY AS THE LOW CONTINUES WESTWARD. WINDS AT
NAPLES WILL REMAIN LIGHT AND VARIABLE THROUGH THE PERIOD AS
UNCERTAINTY REGARDING THE EXACT TRACK OF THE LOW RELATIVE TO THE
APF TERMINAL REMAINS HIGH AT THIS TIME. AS THE LOW SHIFTS WESTWARD
OFF OF THE NAPLES COAST...LIGHT TO MODERATE SE WINDS WILL RETURN
ACROSS THE AREA. /85
MARINE...
A WEAK AREA OF LOW PRESSURE NEAR THE PALM BEACH COAST EARLY THIS
MORNING WILL MOVE ACROSS SOUTH FLORIDA TODAY...AND THEN INTO THE
REGIONAL GULF WATERS TONIGHT. RAIN CHANCES WILL REMAIN HIGH OVER
THE ATLANTIC AND GULF WATERS TODAY INTO THE WEEKEND. THE NHC IS
MONITORING THIS AREA OF LOW PRESSURE...AND THERE IS A MEDIUM
CHANCE OF DEVELOPMENT ONCE IT MOVES INTO THE GULF OF MEXICO. THIS
COULD IMPACT THE GULF FORECAST OVER THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 87 76 88 76 / 70 40 50 40
FORT LAUDERDALE 85 77 89 77 / 70 40 60 40
MIAMI 85 77 89 77 / 70 40 60 40
NAPLES 86 73 89 74 / 70 50 70 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...84/AK
LONG TERM....84/AK
AVIATION...21/KM
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1008 PM EDT SAT SEP 13 2014
.SYNOPSIS...
A COLD FRONT TO THE NORTH AND WEST WILL STALL NEARBY THROUGH EARLY
NEXT WEEK...BEFORE A STRONGER COLD FRONT PUSHES THROUGH THE REGION
BY THE MIDDLE OF THE WEEK. STRONG SURFACE HIGH PRESSURE WILL BUILD
FROM THE NORTH IN THE WAKE OF THE FRONT DURING THE LATE WEEK PERIOD.
&&
.NEAR TERM /THROUGH SUNDAY/...
OPERATIONAL EMC RAP MODEL INDICATED SHORTLY AFTER 00Z THAT 0-3KM
MLCAPES VALUES HAD INCREASED INTO THE 150/175 J/KG RANGE WHICH
WAS ENOUGH TO BREAK WEAK CAPPING IN PARTS OF SE GEORGIA W OF I-95.
DEEP CONVECTION ALONG WITH LOCALIZED TORRENTIAL RAINS AND FREQUENT
LIGHTNING STRIKES BETWEEN SPRINGFIELD AND GLENNVILLE GEORGIA.
TSTMS DEVELOPED ALONG MESOSCALE BOUNDARIES AND SURVIVED TO THIS
POINT VIA COMPLEX MULTI-CELL INTERACTIONS. A SMALL POCKET OF UPPER
DIFLUENCE LIKELY ASSISTED SOME OF THE STRONGER UPDRAFTS W AND NW
OF SAVANNAH AND HINESVILLE THIS EVENING.
00Z CHARLESTON SOUNDING PORTRAYED PWATS OVER 2.3 INCHES WITH DECENT
ELEVATED INSTABILITY. WE MAINTAINED THE POTENTIAL FOR ADDITIONAL
SHOWERS AND TSTMS TO DEVELOP ACROSS THE REGION OVERNIGHT BUT THE
MAIN FOCUS AFTER 2-3 AM SHOULD SHIFT UP TOWARD THE CHARLESTON/BERKELEY
COUNTY REGION AS A BACKDOOR COLD FRONT SAGS INTO SOUTH CAROLINA.
WE INITIALIZED WITH HIGHER POPS IN SE GEORGIA THROUGH MIDNIGHT AND
SHIFTED THEM TOWARD THE IMMEDIATE COASTAL AREAS NORTH OF SAVANNAH
LATE.
NO OTHER SIGNIFICANT CHANGES MADE TO THE LATE EVENING UPDATE WITH
MINOR TEMP TWEAKS AND VARIABLE LIGHT WIND DIRECTIONS IN MANY PLACES.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
SUNDAY...THE SECOND DAY OF THE WEEKEND PROMISES TO BE A FAIRLY
ACTIVE CONVECTIVE DAY...COURTESY OF ABUNDANT AND DEEP MOISTURE...A
COLD FRONT SITUATED ACROSS THE FORECAST AREA...SOME UPPER LEVEL
DIVERGENCE AND ADEQUATE INSTABILITY. THE CHALLENGE THOUGH WILL BE
TWOFOLD...WHERE THE FRONT WILL ORIENT ITSELF AND THUS THE RESULTING
COVERAGE OF CONVECTION...PLUS OUR DIURNAL TEMP CURVE WHICH WILL BE
DICTATED TO THE FIRST CONDITION.
THE DAY WILL START WITH LEFTOVER SCATTERED CONVECTION NEAR OR JUST
OUTSIDE OUR NW ZONES IN PROXIMITY TO THE 850 MB FRONT...WITH A
GREATER CONCENTRATION NEAR THE IMMEDIATE COAST OR MORE LIKELY JUST
OFFSHORE. WITH CONVECTIVE TEMPS IN THE LOWER AND MIDDLE 80S HOWEVER
LAND BASED CONVECTION WILL DEVELOP QUICKLY...AND COVERAGE WILL
INCREASE DURING THE SECOND HALF OF THE MORNING INTO THE AFTERNOON.
FOR NOW WE HAVE PAINTED THE BEST RISK OF SHOWERS AND T-STORMS FROM
CHARLESTON AND BERKELEY COUNTIES TO LOCATIONS WEST AND SW OF
SAVANNAH IN PROXIMITY TO THE COLD FRONT AND WHERE IT INTERACTS WITH
THE SEA BREEZE AND VARIOUS MESO-SCALE BOUNDARIES. HIGHEST
PROBABILITIES WILL BE 60-70 PERCENT IN THESE LOCATIONS...WITH 40-50
POPS ELSEWHERE. STORM MOTION IS SLUGGISH AND WITH PWATS BETWEEN 1
AND 2 STANDARD DEVIATIONS ABOVE NORMAL WE ANTICIPATE OCCASIONAL
HEAVY RAINS AND AT LEAST MINOR FLOODING CONCERNS. IN FACT WITH THE
COLD FRONT IN THE VICINITY WE MIGHT NEED TO CONSIDER A LARGER AND
MORE ENHANCED RISK OF FLOODING. FOR NOW WE/LL ADD TO THE HAZARDOUS
WEATHER OUTLOOK...BUT ANY FLASH FLOOD WATCH POTENTIAL IS NOT YET
HIGH ENOUGH TO WARRANT ISSUING SUCH A PRODUCT.
CONSIDERABLE CLOUD COVER WILL HOLD TEMPS DOWN IN THE MID OR UPPER
80S...AND THE ONSET OF THE RAIN-COOLED ENVIRONMENT WILL RESULT THE
DIURNAL TEMP CURVE BOUNCING AROUND PENDING WHEN AND WHERE IT/S
RAINING. WE HAVE TRENDED THE CURVE TOWARD SUCH CONDITIONS BUT NO
DOUBT FUTURISTIC ADJUSTMENTS WILL BECOME NECESSARY.
SUNDAY NIGHT...INTERACTING/MERGING BOUNDARIES AND PLENTIFUL MOISTURE
WILL ALLOW FOR ONLY SLOWLY DIMINISHING CONCENTRATION TO SHOWERS AND
T-STORMS IN THE EVENING. AND GIVEN THE COLD FRONT LYING NEAR OR
CENTRAL ZONES WE ARE COMPELLED TO HOLD ONTO SLIGHT CHANCE AND CHANCE
POPS EVEN AFTER MIDNIGHT. THERE ARE INDICATIONS OF SOME BUILD-DOWN
OF STRATUS LATE...AND WITH CONDENSATION PRESSURE DEFICITS AS LOW AS
10-30 MB AND SOME LOCALES TO ACHIEVE THEIR CROSS-OVER TEMPS WE ARE
CARRYING PATCHY LATE NIGHT FOG FAR INLAND. LOWS WILL AVERAGE IN THE
LOWER OR MIDDLE 70S...EXCEPT FOR A FEW UPPER 60S NW TIER.
MONDAY...THE SURFACE COLD FRONT BECOMES MORE ILL-DEFINED AS IT
BECOMES MASKED BY SEA BREEZE CIRCULATIONS. IN TURN THE SURFACE
PRESSURE PATTERN IS ALSO LESS PRONOUNCED AND QUITE NEBULOUS.
MESO-SCALE BOUNDARIES AND THE REMNANTS OF THE COLD FRONT WILL HAVE
AMPLE MOISTURE AN INSTABILITY TO AGAIN TRIGGER AN ENHANCED RISK FOR
SHOWERS AND T-STORMS. COVERAGE WILL INCREASE DURING THE LATE MORNING
AND AFTERNOON AS WE ACHIEVE OUR CONVECTIVE TEMPS AND BOUNDARY
INTERACTIONS OCCUR. HIGHEST CHANCES WILL BE INLAND FROM THE US-17
CORRIDOR...PEAKING IN THE 50-60 PERCENTILE. WIND FIELDS IN THE
STEERING LAYER FROM ROUGHLY 800-600 MB IS YET AGAIN
WEAK...SUPPORTIVE OF LOCALLY HEAVY RAINFALL. AND SIMILAR TO MONDAY
OUR TEMPS WILL BE DICTATED BY ONSET OF CONVECTION...BUT STILL WE
SHOULD REACH THE MID AND UPPER 80S ACROSS THE BOARD.
TUESDAY...A BROAD TROUGH WILL HAVE SET UP ACROSS THE EASTERN UNITED
STATES AND WILL SEND THE NEXT UPSTREAM COLD FRONT TOWARD THE
FORECAST AREA FROM THE NW LATE IN THE PERIOD. EMBEDDED WITHIN THE
TROUGH WE FIND A FAIRLY WELL DEFINED SHORT WAVE THAT WAS LOCATED IN
NORTHERN OLD MEXICO ON SATURDAY...THAT SHIFTS THROUGH DURING THE
DAY. THE ADDITIONAL FORCING ALOFT WITH THIS FEATURE PLUS THE RIGHT
ENTRANCE REGION TO THE NEARBY UPPER JET WILL TRIGGER AT LEAST
SCATTERED POPS. THERMODYNAMICS ARE GOOD AND THERE IS SOME STRONGER
MID LEVEL FLOW WITH 0-6 KM BULK SHEAR ON THE ORDER OF 25-30
KT...WHICH POINTS TOWARD THE POTENTIAL OF A FEW STRONGER OR EVEN
ISOLATED SEVERE STORMS. A DEEP OFFSHORE FLOW WILL HELP IN NEGATING
THE EXTENSIVE CLOUD COVER AND TEMPS WILL MAX OUT NEAR MID-SEPTEMBER
NORMS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THE AXIS OF THE UPPER TROUGH WILL BE AMPLIFYING JUST UPSTREAM BY
THE MID WEEK PERIOD...WHILE THE COLD FRONT MOVING OFF THE
COASTLINE STALLS JUST TO THE SOUTH AND EAST. SHORTWAVE ENERGY
MOVING ALONG THE BASE OF THE UPPER TROUGH COULD SUPPORT THE
FORMATION OF LOW PRESSURE WAVES ALONG THE LINGERING OFFSHORE FRONT
WEDNESDAY THROUGH LATE WEEK. SURFACE HIGH PRESSURE WILL BE
BUILDING STRONGLY FROM THE NORTH AT THE SAME TIME...WITH THE
OFFSHORE LOW PRESSURE/COASTAL TROUGH FORMING THE PERIPHERY OF A
WELL-DEFINED INLAND WEDGE STRETCHING DOWN THE APPALACHIAN REGION.
IF THIS PATTERN EVOLVES AS MEDIUM RANGE MODEL SOLUTIONS ARE
SUGGESTING...THEN STRONG NORTH/NORTHEAST FLOW COULD DEVELOP
THURSDAY INTO POSSIBLY THE WEEKEND AND SUPPORT NOTABLY COOLER
CONDITIONS. HAVE INDICATED HIGH TEMPERATURES BEHIND THE FRONT ON
WEDNESDAY IN THE MID 80S...TRENDING EVEN COOLER IN THE LOW 80S FOR
THE LATE WEEK TIME FRAME. LOW TEMPERATURES WILL ALSO REFLECT THE
WEDGE PATTERN...FALLING INTO THE LOW TO MID 60S BY THURSDAY NIGHT.
RAIN CHANCES WILL STILL BE RATHER HIGH IN THE 30 TO 40 PERCENT
RANGE ON WEDNESDAY AND THURSDAY...WITH BEST COVERAGE ACROSS
SOUTHERN AREAS CLOSEST TO THE LINGERING FRONT. SHOWER/THUNDERSTORM
POTENTIAL IS THEN EXPECTED TO DECREASE FRIDAY AND SATURDAY...AS
THE BEST MOISTURE AND CONVERGENCE REMAINS OFFSHORE WITH THE
INTENSIFYING COASTAL TROUGH.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
MOSTLY VFR THROUGH LATER TONIGHT. THEN AS A WEAK BACKDOOR FRONT
SAGS INTO THE REGION TOWARD DAYBREAK ON SUNDAY...CHANCES FOR LOWER
CLOUDS IN THE IFR/MVFR RANGE WILL INCREASE. IT IS UNCERTAIN HOW
FAR THE BOUNDARY WILL REACH BY MID TO LATE MORNING WITH 18Z
GUIDANCE SOMEWHAT SLOWER THAN THE 12Z MODEL RUN. MODELS DO SUGGEST
SHOWERS WILL BE SCATTERED TO NUMEROUS ON SUNDAY...ESPECIALLY AT KCHS
WITH AN INFLUX OF ATLC MOISTURE. SIMILAR CONDITIONS AT KSAV BUT WE
HAVE LEANED MORE TOWARD VCSH THAT PREVAILING SHOWERS. TSTMS ARE
POSSIBLE BUT CONFIDENCE IN TIMING/OCCURRENCE ARE LOW.
EXTENDED AVIATION OUTLOOK...PERIODIC RAIN CHANCES AND POSSIBLE
TEMPORARY FLIGHT RESTRICTIONS THROUGH EARLY NEXT WEEK...AS A COLD
FRONT STALLS OVER OR NEAR THE AREA. SOME EARLY MORNING FOG AND/OR
LOW CLOUDS WILL ALSO BE POSSIBLE...ALSO RESULTING IN THE RISK OF
SUB-VFR WEATHER.
&&
.MARINE...
OVERNIGHT...A WEAK COLD FRONT WILL SHIFT SOUTHEAST TOWARD THE
NORTHERN SOUTH CAROLINA WATERS. A WEAK PRESSURE GRADIENT IS IN
PLACE. WINDS MAINLY 10 KT OR LESS AND SEAS 1-2 FT OVERNIGHT. WINDS
WILL BE VARIABLE IN DIRECTIONS AT TIMES.
SUNDAY THROUGH TUESDAY...OUTSIDE OF CONVECTION AND ANY POTENTIAL
WATERSPOUT ACTIVITY...WIND AND SEA CONDITIONS WILL BE RATHER QUIET.
WINDS WILL TURN ONSHORE SUNDAY INTO SUNDAY NIGHT...BEFORE
TEMPORARILY VEERING TO AN OFFSHORE FETCH LATE SUNDAY NIGHT/EARLY
MONDAY WITH LAND BREEZE INFLUENCES. THE PATTERN WILL THEN START ANEW
AGAIN LATER MONDAY MORNING AND PERSIST INTO TUESDAY. MARINERS SHOULD
MONITOR NOAA WEATHER RADIO ALL HAZARDS OR ASSOCIATED VHF CHANNELS
SINCE THERE IS A RISK FOR OCCASIONAL STRONGER STORMS THROUGH THE
PERIOD.
WEDNESDAY THROUGH FRIDAY...A MID WEEK AND STRONGER COLD FRONT WILL
PUSH THROUGH THE LOCAL WATERS AS A BUILDING HIGH PRESSURE WEDGE
DEVELOPS INLAND. A ROBUST PINCHING OF THE NE GRADIENT WILL GRADUALLY
DEVELOP FOR THURSDAY AND FRIDAY...AND WINDS AND SEAS WILL BE
SIGNIFICANTLY HIGHER. SMALL CRAFT ADVISORIES SEEM A GOOD BET THE
SECOND PART OF THE WEEK.
WATERSPOUTS...CONDITIONS APPEAR TO FAVOR THE DEVELOPMENT OF
WATERSPOUTS SUNDAY MORNING GIVEN LIGHT WIND FIELDS...SUFFICIENT
MOISTURE AND INSTABILITY AND AN EAST/NE TO SW/WEST ALIGNED COLD FRONT
BISECTING COASTAL WATERS. HOWEVER...SINCE ANY WATERSPOUTS WILL BE SO
ISOLATED IN SCOPE WE WILL DEFER TO THE MIDNIGHT FORECASTERS AS TO
WHETHER TO ADD TO THE HAZARDOUS WEATHER OUTLOOK AND/OR TO ISSUE A
MARINE WEATHER STATEMENT.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...
SHORT TERM...33
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
246 AM CDT FRI SEP 12 2014
.DISCUSSION...
905 PM CDT
MAIN FOCUS THIS EVENING IS ON POPS. FIRST...AN AREA OF SHEARED
VORTICITY STRETCHING FROM SOUTHERN NEBRASKA TO SOUTHEAST IOWA IS
CONTINUING TO GENERATE SOME SPOTTY SHOWER ACTIVITY ACROSS THESE
AREAS BUT THE FOCUS OF FORCING SHOULD DIMINISH THROUGH THE
EVENING. THUS AM NOT EXPECTING MEASURABLE PRECIP WITH THIS FEATURE
THOUGH SOME SPRINKLES CANNOT BE RULED OUT.
ATTENTION TURNS TO LAKE EFFECT SHOWERS THROUGH THE OVERNIGHT. WITH
HIGH PRESSURE SPREADING ACROSS THE CENTRAL/NORTHERN PLAINS AND MID
AND UPPER MISSISSIPPI RIVER VALLEY THE EVOLVING PRESSURE GRADIENT
WILL LEAD TO A NORTHEASTERLY LOW LEVEL FLOW OVERNIGHT. LAKE TO H85
DELTA T OF AROUND 17C IS CERTAINLY SUPPORTIVE OF LAKE EFFECT BUT
INVERSION HEIGHTS ARE ON THE LOWER END OF THE FAVORABLE SCALE
PEAKING AROUND 6 KFT. RADAR CONTINUES TO SHOW BANDS OF WEAK
RETURNS OVER SOUTHERN LAKE MICHIGAN WITH SOME SPOTTY RAIN REPORTED
EARLIER IN NW INDIANA. RADAR TRENDS SHOW THE LOW LEVEL FLOW HAS
BEGUN TO TURN NORTHEASTERLY. EXPECT THAT INTENSITY MAY BEGIN TO
INCREASE WITH TIME AS CONVERGENCE LIKELY BECOMES BETTER FOCUSED
INTO THE OVERNIGHT. STILL DECIDING ON DETAILS BUT AM PLANNING ON
INCREASING POPS AND ADJUSTING TO COVERAGE WORDING ACROSS MUCH OF
THE CHICAGO METRO THROUGH THE OVERNIGHT...WITH BEST CHANCES AFTER
MIDNIGHT. OTHERWISE HAVE ADJUSTED TEMPS TO BETTER REFLECT HOURLY
TRENDS WITH MINIMAL CHANGE TO OVERNIGHT LOWS.
MDB
//PREV DISCUSSION...
240 PM...FORECAST CONCERNS INCLUDE MUCH BELOW NORMAL TEMPERATURES
AND CHANCES FOR SHOWERS THROUGH SATURDAY AND AGAIN ON MONDAY.
STRATUS DECK HAS REMAINED MOSTLY OVERCAST TODAY AND THAT HAS HELD
TEMPS IN THE LOWER/MID 50S MOST AREAS...SOME 20 TO 25 DEGREES
BELOW NORMAL FOR MID SEPTEMBER. SEE CLIMATE SECTION BELOW FOR
RECORDS. CLOUD COVER IS EXPECTED TO REMAIN AT LEAST BROKEN IF NOT
OVERCAST OVERNIGHT INTO FRIDAY MORNING...SO NOT EXPECTING MUCH OF
A SWING IN TEMPS WITH LOWS TONIGHT IN THE MID/UPPER 40S.
AS COLDER AIR CONTINUES TO SPREAD ACROSS THE AREA...A FEW LAKE
EFFECT RAIN SHOWERS HAVE DEVELOPED OVER THE SOUTHEASTERN PART OF
THE LAKE. AS HIGH PRESSURE MOVES NORTH OF THE AREA TONIGHT...
WINDS WILL TURN MORE NORTHEAST AND THESE LAKE EFFECT RAIN SHOWERS
WILL BEGIN TO AFFECT NORTHEAST IL OVERNIGHT INTO FRIDAY MORNING.
COVERAGE REMAINS A BIT UNCERTAIN AND HAVE ONLY BUMPED POPS UP TO
LOW CHANCE. TRENDS WILL NEED TO BE MONITORED LATER TONIGHT WITH
THE POSSIBILITY THAT POPS WILL NEED TO BE BUMPED UP FURTHER.
LAKE EFFECT RAIN SHOWERS WILL CONTINUE INLAND ACROSS NORTHERN IL
FRIDAY MORNING AS FLOW TURNS MORE EAST/NORTHEAST. CLOUD COVER WILL
LIKELY REMAIN MOSTLY CLOUDY AND THIS COULD LIMIT TEMPS TO JUST THE
50S AGAIN ON FRIDAY. SOUTHERN AREAS MAY SEE A FEW BREAKS WITH THE
POTENTIAL TO REACH 60...BUT OVERALL FRIDAY WILL CONTINUE MUCH
BELOW NORMAL.
AN UPPER WAVE WILL MOVE ACROSS THE REGION FRIDAY AFTERNOON INTO
FRIDAY EVENING WITH SHOWERS/LIGHT RAIN SPREADING ACROSS THE
NORTHWEST CWA IN THE AFTERNOON THEN ACROSS MUCH OF THE AREA EARLY
FRIDAY EVENING. BUMPED POPS UP SOME...WITH LIKELY OVER THE
NORTHERN TWO THIRDS OF THE CWA...POSSIBLE POPS WILL NEED TO BE
INCREASED HERE AS WELL...THOUGH TOTAL QFP AMOUNTS SHOULD BE IN THE
0.25 TO 0.5 INCH RANGE. THIS WAVE IS FAIRLY PROGRESSIVE...SO
TRIMMED POPS FROM THE WEST OVERNIGHT. LAKE EFFECT RAIN SHOWERS MAY
CONTINUE INTO NORTHWEST INDIANA SATURDAY MORNING BEFORE ENDING IN
THE AFTERNOON.
DESPITE SOME SUNSHINE SATURDAY...AIRMASS WILL BE EVEN COLDER THAN
TODAY AND FRIDAY. NOT SURE HOW MUCH MID SEPTEMBER SUN WILL AID
TEMP INCREASE SO MAINTAINED JUST LOWER 60S FOR HIGHS. HIGH
PRESSURE PASSES ACROSS THE REGION SATURDAY NIGHT INTO SUNDAY
MORNING WITH LOWS DIPPING INTO THE LOWER 40S MOST AREAS...BUT
WARMER IN THE IMMEDIATE CHICAGO METRO AREA.
ANOTHER FAST MOVING WAVE WILL MOVE ACROSS THE AREA MONDAY
BRINGING ANOTHER CHANCE OF SHOWERS. DEPENDING ON TIMING...CLOUD
COVER AND PRECIP COULD HOLD TEMPS DOWN MONDAY BUT FOR NOW HAVE
MAINTAINED 60S. BEYOND MONDAY...HIGH PRESSURE SPREADS ACROSS THE
REGION WITH DRY WEATHER EXPECTED MID WEEK BUT TEMPS STILL BELOW
NORMAL. CMS
&&
.CLIMATE...
900 PM CDT SEP 11 2014
AN UNSEASONABLY COOL AIR MASS OVER THE REGION INTO THE WEEKEND
COULD PUT RECORD TEMPERATURES IN JEOPARDY AT CHICAGO AND
ROCKFORD. RECORD LOW MAX TEMPERATURES ARE MOST LIKELY TO BE
THREATENED.
RECORD LOW MAX TEMPERATURES SEPTEMBER 12-13
-------------------------------------------
SEPTEMBER 12 SEPTEMBER 13
------------ ------------
CHICAGO 53/1902 55/1880
ROCKFORD 56/1943 55/1970
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NNW/N WINDS OVERNIGHT INTO EARLY FRIDAY TURNING NORTHEAST.
* PERIODS OF MVFR CIGS. IFR A POSSIBILITY ESPECIALLY FRIDAY
EVENING.
* RAIN MOVING ACROSS THE REGION FRIDAY EVENING.
BMD
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE IS STARTING TO BUILD IN FROM THE NORTHWEST OVERNIGHT
WITH LOWER CLOUDS STARTING TO ERODE. RFD ALREADY SOLIDLY IN AREA OF
VFR CONDITIONS...AND INTERMITTENTLY VFR CONDITIONS ARE IN PLACE
OVER THE CHICAGO TERMINALS. EXPECT MOST OF THE OVERNIGHT HOURS TO BE
VFR UNTIL WINDS TURN NORTHEAST FRIDAY WITH FLOW OFF THE LAKE
BRINGING LOWER LAKE EFFECT CLOUDINESS/SHOWERS BACK OVERHEAD. TIMING
THIS SHIFT REMAINS A BIT UNCERTAIN WITH LOWER RES MODEL GUIDANCE
SUGGESTING EARLIER TIMING WHILE HIGH RES GUIDANCE SUGGEST THAT THE
NNW/N WINDS WILL HOLD ON LATER INTO THE MORNING. FOR NOW...FEEL THAT
THE HIGH RES GUIDANCE HAS A BETTER HANDLE ON THE LOW LEVEL
CONVERGENCE OVER THE LAKE WHICH WOULD RESULT IN WINDS STAYING BACKED
LONGER OVER THE CHICAGO TERMINALS. THAT SAID THERE REMAINS LOW
CONFIDENCE ON TIMING THE SWITCH TO NORTHEAST...THOUGH WHEN IT DOES
HAPPEN IT WILL LIKELY BE IN THE 10-12KT RANGE. LAKE EFFECT LIGHT
SHOWERS/SPRINKLES ARE EXPECTED TO MOVE INLAND AND MAY MOVE OVER THE
TERMINALS PERIODICALLY...THOUGH IMPACTS TO VSBY SHOULD BE MINIMAL.
AN UPPER LEVEL DISTURBANCE IS PROGGED TO MOVE OVER THE AREA FRIDAY
EVENING AND SHOULD BRING MORE WIDESPREAD RAIN TO THE AREA...ALONG
WITH THE POSSIBILITY OF IFR CIGS.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN WINDS OVERNIGHT...AND HIGH CONFIDENCE IN A
WIND SHIFT TO THE NORTHEAST...BUT LOW CONFIDENCE IN TIMING.
* MEDIUM CONFIDENCE IN CIG TRENDS...EXCEPT LOW CONFIDENCE FRIDAY
EVENING WITH RAIN.
* MEDIUM-HIGH CONFIDENCE IN RAIN MOVING ACROSS THE REGION FRIDAY
EVENING.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR.
SUNDAY...SCHC SHRA LATE.
MONDAY...CHC SHRA THEN SCHC SHRA OVERNIGHT. MVFR CIGS PSBL.
TUESDAY AND WEDNESDAY...VFR.
JEE
&&
.MARINE...
246 AM CDT
RIDGING IS IN PLACE THIS MORNING OVER LAKE MICHIGAN AND WINDS
SHOULD HOLD FAIRLY STEADY THROUGH THE DAY TODAY. TONIGHT
HOWEVER...LOW PRESSURE IS PROGGED TO DEVELOP OVER THE UPPER OHIO
VALLEY AND LIFT TOWARDS THE EASTERN LAKES CAUSING THE GRADIENT TO
TIGHTEN. IN ADDITION...STRONG LAKE INDUCED INSTABILITY WITH THE
UNSEASONABLY COOL AIRMASS AND COLD UPPER LOW WILL RESULT IN A BAND
OF LAKE EFFECT SHOWERS AND THUNDERSTORMS THAT WILL RESULT IN
ADDITIONAL LOW LEVEL CONVERGENCE. THE NET RESULT OF ALL THIS WILL
BE AN INCREASE IN WINDS...ESPECIALLY OVER THE SOUTH HALF OF THE
LAKE WHERE WINDS ARE EXPECTED TO INCREASE TO 30 KT FOR A SHORT
PERIOD...AND CANNOT RULE OUT SOME GALES...ESPECIALLY NEAR THE
BETTER CONVERGENCE WITHIN THE LAKE EFFECT BAND. THE SMALL CRAFT
ADVISORY MAY HAVE TO BE EXTENDED...PARTICULARLY FOR THE INDIANA
ZONES. CONDITIONS MAY BE MORE MARGINAL OVER THE ILLINOIS ZONES
WITH OFFSHORE FLOW. IN ADDITION TO THE STRONGER WINDS...CONDITIONS
WILL BE FAVORABLE FOR THE FORMATION OF WATERSPOUTS TONIGHT INTO
EARLY SATURDAY. WINDS WILL DIMINISH THROUGH THE DAY SATURDAY AS
HIGH PRESSURE BUILDS OVERHEAD...THEN TURN SOUTHWEST AND FRESHEN UP
OVER THE NORTH HALF OF THE LAKE SUNDAY AS THE HIGH SLIPS EAST OF
THE AREA AND ANOTHER LOW SKIRTS EAST OVER THE CANADIAN PRAIRIES.
THIS LOW WILL DRAG ANOTHER COLD FRONT ACROSS LAKE MICHIGAN ON
MONDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 5 PM SATURDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 5 PM SATURDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
233 AM CDT Fri Sep 12 2014
.SHORT TERM...(Today)
ISSUED AT 233 AM CDT FRI SEP 12 2014
Short-wave trough evident on 07z/2am water vapor imagery over
western South Dakota will track E/NE today, spreading clouds and
showers across Iowa into north-central Illinois. All models agree
that precip will remain west of the KILX CWA until afternoon, so
have gone with a mostly cloudy and dry forecast this morning. Still
some model discrepancies concerning QPF with this system: however,
it appears the strongest forcing for widespread precip will
generally shift into Wisconsin/northern Illinois later today. Have
therefore focused highest PoPs across the northwest CWA this
afternoon, with dry conditions expected to continue for the balance
of the day east of the I-55 corridor. High temperatures will once
again be well below normal for this time of year, with readings
ranging from the upper 50s north to the middle 60s far south.
&&
.LONG TERM...(Tonight through Thursday)
ISSUED AT 233 AM CDT FRI SEP 12 2014
Upper wave will pass into the Great Lakes tonight, with most
concentrated area of showers skimming central Illinois to the
north. As a result of the expected track of the strongest forcing
and the diurnal nature of the precip, have focused chance PoPs
across the north, with only slight chances further south. Total
rainfall with this feature will be quite light, only amounting to
one tenth of an inch or less. Showers will come to an end from west
to east after midnight, with partial clearing occurring across the
Illinois River Valley late.
High pressure will build in from the Plains on Saturday, resulting
in a return to sunny and dry conditions. Temperatures will remain
below normal through the weekend, with afternoon highs mainly in the
60s and overnight lows dipping into the 40s. Next northern stream
short-wave is still on target for early next week. Both the GFS and
ECMWF show this feature tracking across central Illinois on Monday,
and both models try to bring light precip into the NW CWA as early
as Sunday night. Given dry airmass initially in place, have gone
with a dry forecast across the board Sunday night followed by high
chance PoPs on Monday as stronger forcing and deeper moisture
arrive. After that, cool and dry weather will once again take hold
across the Midwest Tuesday through Thursday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1144 PM CDT THU SEP 11 2014
MVFR clouds will prevail over the next 24 hours, with some
periodic IFR cloud heights possible late tonight and early Friday
morning. Did not include IFR, as RAP soundings show 1200FT as the
base of the cloud layer. Subsidence under a cold dome of high
pressure is keeping a blanket of low moisture in place across much
of the Upper Midwest. A fast moving shortwave continues to trigger a
narrow band of showers across south-central Iowa, that are drifting
toward N IL. No precip was included at PIA the rest of the night,
as the trajectory of the showers and forecast soundings do not
look supportive of precip that far south with this wave. There is
some indication that drizzle may develop for PIA, SPI and BMI
later tonight into Friday morning. As the upper trough rotates
into N IL tomorrow, coverage of showers will increase west of
I-55. We included a VCSH in the afternoon for all sites but CMI,
where VCSH was included after 00z. Shower chances will continue
through the end of the TAF period at 06z.
Winds will remain north to northeast over the next 24 hours, with
wind speeds climbing to around 10kt during the day, and
diminishing to 5-7kt at night.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1235 AM CDT FRI SEP 12 2014
.DISCUSSION...
905 PM CDT
MAIN FOCUS THIS EVENING IS ON POPS. FIRST...AN AREA OF SHEARED
VORTICITY STRETCHING FROM SOUTHERN NEBRASKA TO SOUTHEAST IOWA IS
CONTINUING TO GENERATE SOME SPOTTY SHOWER ACTIVITY ACROSS THESE
AREAS BUT THE FOCUS OF FORCING SHOULD DIMINISH THROUGH THE
EVENING. THUS AM NOT EXPECTING MEASURABLE PRECIP WITH THIS FEATURE
THOUGH SOME SPRINKLES CANNOT BE RULED OUT.
ATTENTION TURNS TO LAKE EFFECT SHOWERS THROUGH THE OVERNIGHT. WITH
HIGH PRESSURE SPREADING ACROSS THE CENTRAL/NORTHERN PLAINS AND MID
AND UPPER MISSISSIPPI RIVER VALLEY THE EVOLVING PRESSURE GRADIENT
WILL LEAD TO A NORTHEASTERLY LOW LEVEL FLOW OVERNIGHT. LAKE TO H85
DELTA T OF AROUND 17C IS CERTAINLY SUPPORTIVE OF LAKE EFFECT BUT
INVERSION HEIGHTS ARE ON THE LOWER END OF THE FAVORABLE SCALE
PEAKING AROUND 6 KFT. RADAR CONTINUES TO SHOW BANDS OF WEAK
RETURNS OVER SOUTHERN LAKE MICHIGAN WITH SOME SPOTTY RAIN REPORTED
EARLIER IN NW INDIANA. RADAR TRENDS SHOW THE LOW LEVEL FLOW HAS
BEGUN TO TURN NORTHEASTERLY. EXPECT THAT INTENSITY MAY BEGIN TO
INCREASE WITH TIME AS CONVERGENCE LIKELY BECOMES BETTER FOCUSED
INTO THE OVERNIGHT. STILL DECIDING ON DETAILS BUT AM PLANNING ON
INCREASING POPS AND ADJUSTING TO COVERAGE WORDING ACROSS MUCH OF
THE CHICAGO METRO THROUGH THE OVERNIGHT...WITH BEST CHANCES AFTER
MIDNIGHT. OTHERWISE HAVE ADJUSTED TEMPS TO BETTER REFLECT HOURLY
TRENDS WITH MINIMAL CHANGE TO OVERNIGHT LOWS.
MDB
//PREV DISCUSSION...
240 PM...FORECAST CONCERNS INCLUDE MUCH BELOW NORMAL TEMPERATURES
AND CHANCES FOR SHOWERS THROUGH SATURDAY AND AGAIN ON MONDAY.
STRATUS DECK HAS REMAINED MOSTLY OVERCAST TODAY AND THAT HAS HELD
TEMPS IN THE LOWER/MID 50S MOST AREAS...SOME 20 TO 25 DEGREES
BELOW NORMAL FOR MID SEPTEMBER. SEE CLIMATE SECTION BELOW FOR
RECORDS. CLOUD COVER IS EXPECTED TO REMAIN AT LEAST BROKEN IF NOT
OVERCAST OVERNIGHT INTO FRIDAY MORNING...SO NOT EXPECTING MUCH OF
A SWING IN TEMPS WITH LOWS TONIGHT IN THE MID/UPPER 40S.
AS COLDER AIR CONTINUES TO SPREAD ACROSS THE AREA...A FEW LAKE
EFFECT RAIN SHOWERS HAVE DEVELOPED OVER THE SOUTHEASTERN PART OF
THE LAKE. AS HIGH PRESSURE MOVES NORTH OF THE AREA TONIGHT...
WINDS WILL TURN MORE NORTHEAST AND THESE LAKE EFFECT RAIN SHOWERS
WILL BEGIN TO AFFECT NORTHEAST IL OVERNIGHT INTO FRIDAY MORNING.
COVERAGE REMAINS A BIT UNCERTAIN AND HAVE ONLY BUMPED POPS UP TO
LOW CHANCE. TRENDS WILL NEED TO BE MONITORED LATER TONIGHT WITH
THE POSSIBILITY THAT POPS WILL NEED TO BE BUMPED UP FURTHER.
LAKE EFFECT RAIN SHOWERS WILL CONTINUE INLAND ACROSS NORTHERN IL
FRIDAY MORNING AS FLOW TURNS MORE EAST/NORTHEAST. CLOUD COVER WILL
LIKELY REMAIN MOSTLY CLOUDY AND THIS COULD LIMIT TEMPS TO JUST THE
50S AGAIN ON FRIDAY. SOUTHERN AREAS MAY SEE A FEW BREAKS WITH THE
POTENTIAL TO REACH 60...BUT OVERALL FRIDAY WILL CONTINUE MUCH
BELOW NORMAL.
AN UPPER WAVE WILL MOVE ACROSS THE REGION FRIDAY AFTERNOON INTO
FRIDAY EVENING WITH SHOWERS/LIGHT RAIN SPREADING ACROSS THE
NORTHWEST CWA IN THE AFTERNOON THEN ACROSS MUCH OF THE AREA EARLY
FRIDAY EVENING. BUMPED POPS UP SOME...WITH LIKELY OVER THE
NORTHERN TWO THIRDS OF THE CWA...POSSIBLE POPS WILL NEED TO BE
INCREASED HERE AS WELL...THOUGH TOTAL QFP AMOUNTS SHOULD BE IN THE
0.25 TO 0.5 INCH RANGE. THIS WAVE IS FAIRLY PROGRESSIVE...SO
TRIMMED POPS FROM THE WEST OVERNIGHT. LAKE EFFECT RAIN SHOWERS MAY
CONTINUE INTO NORTHWEST INDIANA SATURDAY MORNING BEFORE ENDING IN
THE AFTERNOON.
DESPITE SOME SUNSHINE SATURDAY...AIRMASS WILL BE EVEN COLDER THAN
TODAY AND FRIDAY. NOT SURE HOW MUCH MID SEPTEMBER SUN WILL AID
TEMP INCREASE SO MAINTAINED JUST LOWER 60S FOR HIGHS. HIGH
PRESSURE PASSES ACROSS THE REGION SATURDAY NIGHT INTO SUNDAY
MORNING WITH LOWS DIPPING INTO THE LOWER 40S MOST AREAS...BUT
WARMER IN THE IMMEDIATE CHICAGO METRO AREA.
ANOTHER FAST MOVING WAVE WILL MOVE ACROSS THE AREA MONDAY
BRINGING ANOTHER CHANCE OF SHOWERS. DEPENDING ON TIMING...CLOUD
COVER AND PRECIP COULD HOLD TEMPS DOWN MONDAY BUT FOR NOW HAVE
MAINTAINED 60S. BEYOND MONDAY...HIGH PRESSURE SPREADS ACROSS THE
REGION WITH DRY WEATHER EXPECTED MID WEEK BUT TEMPS STILL BELOW
NORMAL. CMS
&&
.CLIMATE...
900 PM CDT SEP 11 2014
AN UNSEASONABLY COOL AIR MASS OVER THE REGION INTO THE WEEKEND
COULD PUT RECORD TEMPERATURES IN JEOPARDY AT CHICAGO AND
ROCKFORD. RECORD LOW MAX TEMPERATURES ARE MOST LIKELY TO BE
THREATENED.
RECORD LOW MAX TEMPERATURES SEPTEMBER 12-13
-------------------------------------------
SEPTEMBER 12 SEPTEMBER 13
------------ ------------
CHICAGO 53/1902 55/1880
ROCKFORD 56/1943 55/1970
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NNW/N WINDS OVERNIGHT INTO EARLY FRIDAY TURNING NORTHEAST.
* PERIODS OF MVFR CIGS. IFR A POSSIBILITY ESPECIALLY FRIDAY
EVENING.
* RAIN MOVING ACROSS THE REGION FRIDAY EVENING.
BMD
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE IS STARTING TO BUILD IN FROM THE NORTHWEST OVERNIGHT
WITH LOWER CLOUDS STARTING TO ERODE. RFD ALREADY SOLIDLY IN AREA OF
VFR CONDITIONS...AND INTERMITTENTLY VFR CONDITIONS ARE IN PLACE
OVER THE CHICAGO TERMINALS. EXPECT MOST OF THE OVERNIGHT HOURS TO BE
VFR UNTIL WINDS TURN NORTHEAST FRIDAY WITH FLOW OFF THE LAKE
BRINGING LOWER LAKE EFFECT CLOUDINESS/SHOWERS BACK OVERHEAD. TIMING
THIS SHIFT REMAINS A BIT UNCERTAIN WITH LOWER RES MODEL GUIDANCE
SUGGESTING EARLIER TIMING WHILE HIGH RES GUIDANCE SUGGEST THAT THE
NNW/N WINDS WILL HOLD ON LATER INTO THE MORNING. FOR NOW...FEEL THAT
THE HIGH RES GUIDANCE HAS A BETTER HANDLE ON THE LOW LEVEL
CONVERGENCE OVER THE LAKE WHICH WOULD RESULT IN WINDS STAYING BACKED
LONGER OVER THE CHICAGO TERMINALS. THAT SAID THERE REMAINS LOW
CONFIDENCE ON TIMING THE SWITCH TO NORTHEAST...THOUGH WHEN IT DOES
HAPPEN IT WILL LIKELY BE IN THE 10-12KT RANGE. LAKE EFFECT LIGHT
SHOWERS/SPRINKLES ARE EXPECTED TO MOVE INLAND AND MAY MOVE OVER THE
TERMINALS PERIODICALLY...THOUGH IMPACTS TO VSBY SHOULD BE MINIMAL.
AN UPPER LEVEL DISTURBANCE IS PROGGED TO MOVE OVER THE AREA FRIDAY
EVENING AND SHOULD BRING MORE WIDESPREAD RAIN TO THE AREA...ALONG
WITH THE POSSIBILITY OF IFR CIGS.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN WINDS OVERNIGHT...AND HIGH CONFIDENCE IN A
WIND SHIFT TO THE NORTHEAST...BUT LOW CONFIDENCE IN TIMING.
* MEDIUM CONFIDENCE IN CIG TRENDS...EXCEPT LOW CONFIDENCE FRIDAY
EVENING WITH RAIN.
* MEDIUM-HIGH CONFIDENCE IN RAIN MOVING ACROSS THE REGION FRIDAY
EVENING.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR.
SUNDAY...SCHC SHRA LATE.
MONDAY...CHC SHRA THEN SCHC SHRA OVERNIGHT. MVFR CIGS PSBL.
TUESDAY AND WEDNESDAY...VFR.
JEE
&&
.MARINE...
209 PM CDT
STRONG LOW PRESSURE SYSTEM THAT BROUGHT THE GALE FORCE WINDS HAS
CONTINUED TO LIFT NORTHEAST AWAY FROM THE GREAT LAKES REGION...WITH
THE GRADIENT OVER LAKE MICHIGAN STEADILY WEAKENING. THE GRADIENT
WILL REMAIN JUST ENOUGH TO PRODUCE WINDS BETWEEN 15 AND 25 KT
OVERNIGHT GENERALLY FROM THE NORTH...BEGINNING TO TURN SLIGHTLY
NORTHEAST AHEAD OF THE BROAD RIDGE OF HIGH PRESSURE OVER THE CENTRAL
PLAINS THAT IS POISED TO ARRIVE SATURDAY INTO SUNDAY MORNING.
ANOTHER FRONTAL BOUNDARY WILL ARRIVE FRIDAY EVENING WHICH WILL
PROVIDE A REINFORCING PUSH OF GUSTY NORTH WINDS TO THE LAKE...WITH
THE GRADIENT BEING SLIGHTLY TIGHTER ALONG THE SOUTHERN HALF OF THE
LAKE FRIDAY NIGHT THROUGH EARLY SATURDAY. WAVES WILL REMAIN ELEVATED
THROUGH FRIDAY NIGHT...CREATING HAZARDOUS WAVES TO SMALL CRAFT
THROUGH THIS PERIOD. THEN THE WAVES SHOULD STEADILY DIMINISH BY
EARLY SATURDAY MORNING TO ALLOW THE SMALL CRAFT TO END. HOWEVER IF
THE WINDS REMAIN ELEVATED...THIS WILL KEEP WAVES UP AS WELL THROUGH
DAYBREAK SAT. HIGH PRESSURE IS THEN POISED TO BUILD OVER LAKE
MICHIGAN SATURDAY EVENING AND CONTINUE THROUGH SUNDAY. WHICH WILL
THEN PROVIDE MUCH LIGHTER WINDS AND SUBSIDING WAVES.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 5 PM SATURDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 5 PM SATURDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1144 PM CDT Thu Sep 11 2014
.UPDATE...
ISSUED AT 900 PM CDT THU SEP 11 2014
High pressure at the surface extends from Montana to Ohio, but an
abundance of low level moisture trapped near the surface is
keeping cloud cover across a majority of the Upper Midwest. An
upper level trough positioned on top of the surface high is
focusing jet stream dynamics from South Dakota through the Great
Lakes to Ontario. Short waves in the leading edge of the upper
trough are triggering spotty showers and spreading mid and high
clouds toward western IL. Overall, a blanket of low clouds will
dominate the next 24 to 36 hours, with sunshine probably not making
much of an appearance until Saturday afternoon. Unseasonably cool
conditions will continue during that time as well, with diurnal
swings in temperature generally less than 10F.
The main updates for this evening were to increase cloud cover
tonight and tomorrow, and trim a degree or two from the low temps
across our northern counties. Updated info will be available shortly.
&&
.SHORT TERM...(Tonight)
ISSUED AT 259 PM CDT THU SEP 11 2014
Cold front just south of the Ohio River Valley this afternoon as
high pressure builds into the Midwest. Northerly flow at the sfc
bringing unseasonably cool temps into the region, in stark contrast
to the weather of the last few days. Cooler temperatures expected
to continue into the overnight hours. With lows dipping into the
upper 40s across the nrn portions of the state...and low 50s before
dawn for much of Illinois. Breaks in the cloud cover off to the
west not having much success in moving into the region. As a
result, continued cloud coverage expected through the overnight
hours as llvl RH has remained trapped. Both NAM and HRRR slow to
move clouds out, though some brief clearing is possible NW of the
Illinois River.
&&
.LONG TERM...(Friday through Thursday)
ISSUED AT 259 PM CDT THU SEP 11 2014
Cool and cloudy conditions are expected again Friday as low level
northerly flow continues with a strong capping inversion at around
850 mb. An upper level shortwave will be rapidly approaching from
the west. The axis of the shortwave expected to cross Illinois late
Friday evening to early Saturday morning...pushing another frontal
boundary through the region. Current model forecasts are fairly
consistent keeping precipitation with this feature mainly north of
I-72...and modest amounts around 0.10 inches or less. Have PoPs
beginning Friday afternoon west of I-55 as lift associated with the
approaching shortwave begins...then PoPs spread through most areas
I-55 northward Friday evening. The system moves rapidly east-
northeastward leaving a cool and dry weekend behind it...with highs
in the 60s and lows in the 40s...as high pressure settles over the
area.
The next chance for precipitation will be Monday as models
consistently track another broad trough through the midwest. Cool
dry northwesterly flow aloft is expected to follow for the remainder
of the week with little chance for any precipitation and below
normal temperatures continuing.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1144 PM CDT THU SEP 11 2014
MVFR clouds will prevail over the next 24 hours, with some
periodic IFR cloud heights possible late tonight and early Friday
morning. Did not include IFR, as RAP soundings show 1200FT as the
base of the cloud layer. Subsidence under a cold dome of high
pressure is keeping a blanket of low moisture in place across much
of the Upper Midwest. A fast moving shortwave continues to trigger a
narrow band of showers across south-central Iowa, that are drifting
toward N IL. No precip was included at PIA the rest of the night,
as the trajectory of the showers and forecast soundings do not
look supportive of precip that far south with this wave. There is
some indication that drizzle may develop for PIA, SPI and BMI
later tonight into Friday morning. As the upper trough rotates
into N IL tomorrow, coverage of showers will increase west of
I-55. We included a VCSH in the afternoon for all sites but CMI,
where VCSH was included after 00z. Shower chances will continue
through the end of the TAF period at 06z.
Winds will remain north to northeast over the next 24 hours, with
wind speeds climbing to around 10kt during the day, and
diminishing to 5-7kt at night.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHIMON
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1240 PM CDT FRI SEP 12 2014
.SHORT TERM /TODAY/...
ISSUED AT 333 AM CDT FRI SEP 12 2014
PRECIP AND TEMP TRENDS WILL BE THE PRIMARY CONCERNS TODAY. RIGHT
ENTRANCE REGION DIVERGENCE OF STRONG 120KT JET FROM MO VALLEY INTO
SERN CANADA CONTINUES TO ENHANCE BROAD SWATH OF PRECIP FROM NE/KS
INTO THE NWRN HALF OF IA. FORCING IS MAINLY KINEMATIC AND MID LEVEL
BASED DRIVEN BY DIVERGENCE AND DPVA...AND ALTHOUGH THERE IS LITTLE
TO NO THETA-E ADVECTION BELOW 3KM...THERE DOES APPEAR TO BE FAIRLY
HIGH BASED FRONTOGENETICAL FORCING AND RESPONSE. ENHANCED SW-NE
PRECIP BANDS LINE UP FAIRLY NICELY WITH RAP H7/H5 FN DIVERGENCE AND
LOWER STATIC STABILITY NOTED BY SLIGHTLY NEGATIVE EPV IN THE SAME
LAYER. HIGH RES MODEL PRECIP DEPICTIONS ARE IN QUITE GOOD AGREEMENT
BUT LOOK SLOW AT THE MOMENT SUGGESTING PRECIP WILL MAINLY BE IN THE
MORNING...AND CERTAINLY BE EXITING TO THE EAST 21Z-00Z.
TEMPS WILL BE PROBLEMATIC WITH EXTREMELY ANOMALOUS AIRMASS JUST
UPSTREAM. BOTH THE NAEFS CLIMATOLOGICAL AND GEFS M-CLIMATE
PERCENTILES ARE IN THEIR LOWEST AND HIGHEST RESPECTIVE 1 PERCENT FOR
TEMPS AND MSLP. THIS COLD AIRMASS COMBINED WITH PRECIP WILL RESULT
IN LITTLE TEMP REBOUND TODAY AND SOME NON-DIURNAL TRENDS WITH HIGHS
NO BETTER THAN THE LOWER 50S. ALTHOUGH NOT IN THE FORECAST...WOULD
NOT BE SURPRISED TO SEE A FEW SPOTS STRUGGLE TO REACH 50F. THESE
HIGHS WOULD AGAIN BREAK MIN MAX RECORDS WHICH RANGE FROM 53-56F AT
MASON CITY...WATERLOO...DES MOINES AND OTTUMWA.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 333 AM CDT FRI SEP 12 2014
LITTLE CHANGES TO THE GOING FORECAST AS MODELS REMAIN IN AGREEMENT
BOTH FROM RUN TO RUN AND AMONG EACH OTHER. LARGE AREA OF HIGH
PRESSURE TO BUILD INTO THE STATE TONIGHT WITH DRY CONDITIONS AND
CLEARING SKIES. VERY COLD AIR FOR THIS TIME OF YEAR TO REMAIN IN
PLACE ACROSS THE REGION...WITH H85 TEMPS AROUND 0C TONIGHT AND ONLY
WARMING TO AROUND +5C THROUGH THE WEEKEND. WITH THE COOL AIR AND
HIGH PRESSURE IN PLACE TONIGHT...CLEAR SKIES AND LIGHT WINDS
TEMPERATURES EXPECTED TO DROP OFF QUITE A BIT. HOWEVER THE TEMPS MAY
BE TEMPERED SOME BY THE LINGERING MOISTURE FROM ALL THE RAIN THE
PAST FEW DAYS AND ADDITIONAL RAIN TODAY...WHICH LEADS TO BEING
SOMEWHAT HESITANT ON POTENTIAL FOR FROST FORMATION AS WELL.
THEREFORE STUCK WITH LOWS IN THE MID TO UPPER 30S AND SOME PATCHY
FROST WORDING ACROSS THE WEST/NORTH WHERE COOLEST TEMPS EXPECTED.
HIGH PRESSURE TO DOMINATE OVER THE WEEKEND...WITH TEMPS GRADUALLY
WARMING A BIT. OTHERWISE NEXT CHANCE FOR PRECIPITATION AS ANOTHER
WEAK UPPER LEVEL WAVE AND ASSOCIATED COLD FRONT DROPS THROUGH THE
REGION. ANOTHER LARGE AREA OF HIGH PRESSURE TO THEN BUILD INTO THE
CENTRAL US FOR MUCH OF NEXT WEEK. THERMAL PROFILES WARM SOME WHICH
SHOULD ALLOW TEMPERATURES TO CREEP BACK INTO THE 70S BY WEDNESDAY
INTO THURSDAY. A LARGER UPPER LEVEL WAVE THEN LOOKS TO DIG INTO THE
CENTRAL US BY NEXT FRIDAY INTO THE WEEKEND WHICH SHOULD BRING
ADDITIONAL CHANCES FOR PRECIPITATION TO MUCH OF THE AREA. EVEN WITH
THE WARMING BY THE END OF THE FORECAST PERIOD...TEMPERATURES WILL
REMAIN WELL BELOW THE SEASONAL AVERAGES THROUGH MUCH OF NEXT WEEK.
&&
.AVIATION...12/18Z
ISSUED AT 1232 PM CDT FRI SEP 12 2014
NEXT 6 OR SO HOURS IS WINDOW OF MAIN WEATHER AS TAF SITES HOVER IN
MVFR CEILINGS. AFTER 02Z...ALL SITES BECOMING SKC...WITH CALM WINDS
THROUGH SUNRISE SATURDAY MORNING AS HIGH PRESSURE TO BLAST AWAY
CLOUDS AND PUT ALL TAF SITES INTO VFR. FOR THE REST OF
TODAY...BAND OF SHOWERS TO CONTINUE MOVING EASTWARD. NO REASON FOR
PRECIP TO INTENSIFY AND/OR PRODUCE TS...SO HAVE LEFT THUNDER OUT
OF TAFS AND HAVE NOT REDUCED VSBYS BELOW 6SM.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...BEERENDS
AVIATION...KOTENBERG
AREA FORECAST DISCUSSION
NWS DES MOINES IA
652 AM CDT FRI SEP 12 2014
.SHORT TERM /TODAY/...
ISSUED AT 333 AM CDT FRI SEP 12 2014
PRECIP AND TEMP TRENDS WILL BE THE PRIMARY CONCERNS TODAY. RIGHT
ENTRANCE REGION DIVERGENCE OF STRONG 120KT JET FROM MO VALLEY INTO
SERN CANADA CONTINUES TO ENHANCE BROAD SWATH OF PRECIP FROM NE/KS
INTO THE NWRN HALF OF IA. FORCING IS MAINLY KINEMATIC AND MID LEVEL
BASED DRIVEN BY DIVERGENCE AND DPVA...AND ALTHOUGH THERE IS LITTLE
TO NO THETA-E ADVECTION BELOW 3KM...THERE DOES APPEAR TO BE FAIRLY
HIGH BASED FRONTOGENETICAL FORCING AND RESPONSE. ENHANCED SW-NE
PRECIP BANDS LINE UP FAIRLY NICELY WITH RAP H7/H5 FN DIVERGENCE AND
LOWER STATIC STABILITY NOTED BY SLIGHTLY NEGATIVE EPV IN THE SAME
LAYER. HIGH RES MODEL PRECIP DEPICTIONS ARE IN QUITE GOOD AGREEMENT
BUT LOOK SLOW AT THE MOMENT SUGGESTING PRECIP WILL MAINLY BE IN THE
MORNING...AND CERTAINLY BE EXITING TO THE EAST 21Z-00Z.
TEMPS WILL BE PROBLEMATIC WITH EXTREMELY ANOMALOUS AIRMASS JUST
UPSTREAM. BOTH THE NAEFS CLIMATOLOGICAL AND GEFS M-CLIMATE
PERCENTILES ARE IN THEIR LOWEST AND HIGHEST RESPECTIVE 1 PERCENT FOR
TEMPS AND MSLP. THIS COLD AIRMASS COMBINED WITH PRECIP WILL RESULT
IN LITTLE TEMP REBOUND TODAY AND SOME NON-DIURNAL TRENDS WITH HIGHS
NO BETTER THAN THE LOWER 50S. ALTHOUGH NOT IN THE FORECAST...WOULD
NOT BE SURPRISED TO SEE A FEW SPOTS STRUGGLE TO REACH 50F. THESE
HIGHS WOULD AGAIN BREAK MIN MAX RECORDS WHICH RANGE FROM 53-56F AT
MASON CITY...WATERLOO...DES MOINES AND OTTUMWA.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 333 AM CDT FRI SEP 12 2014
LITTLE CHANGES TO THE GOING FORECAST AS MODELS REMAIN IN AGREEMENT
BOTH FROM RUN TO RUN AND AMONG EACH OTHER. LARGE AREA OF HIGH
PRESSURE TO BUILD INTO THE STATE TONIGHT WITH DRY CONDITIONS AND
CLEARING SKIES. VERY COLD AIR FOR THIS TIME OF YEAR TO REMAIN IN
PLACE ACROSS THE REGION...WITH H85 TEMPS AROUND 0C TONIGHT AND ONLY
WARMING TO AROUND +5C THROUGH THE WEEKEND. WITH THE COOL AIR AND
HIGH PRESSURE IN PLACE TONIGHT...CLEAR SKIES AND LIGHT WINDS
TEMPERATURES EXPECTED TO DROP OFF QUITE A BIT. HOWEVER THE TEMPS MAY
BE TEMPERED SOME BY THE LINGERING MOISTURE FROM ALL THE RAIN THE
PAST FEW DAYS AND ADDITIONAL RAIN TODAY...WHICH LEADS TO BEING
SOMEWHAT HESITANT ON POTENTIAL FOR FROST FORMATION AS WELL.
THEREFORE STUCK WITH LOWS IN THE MID TO UPPER 30S AND SOME PATCHY
FROST WORDING ACROSS THE WEST/NORTH WHERE COOLEST TEMPS EXPECTED.
HIGH PRESSURE TO DOMINATE OVER THE WEEKEND...WITH TEMPS GRADUALLY
WARMING A BIT. OTHERWISE NEXT CHANCE FOR PRECIPITATION AS ANOTHER
WEAK UPPER LEVEL WAVE AND ASSOCIATED COLD FRONT DROPS THROUGH THE
REGION. ANOTHER LARGE AREA OF HIGH PRESSURE TO THEN BUILD INTO THE
CENTRAL US FOR MUCH OF NEXT WEEK. THERMAL PROFILES WARM SOME WHICH
SHOULD ALLOW TEMPERATURES TO CREEP BACK INTO THE 70S BY WEDNESDAY
INTO THURSDAY. A LARGER UPPER LEVEL WAVE THEN LOOKS TO DIG INTO THE
CENTRAL US BY NEXT FRIDAY INTO THE WEEKEND WHICH SHOULD BRING
ADDITIONAL CHANCES FOR PRECIPITATION TO MUCH OF THE AREA. EVEN WITH
THE WARMING BY THE END OF THE FORECAST PERIOD...TEMPERATURES WILL
REMAIN WELL BELOW THE SEASONAL AVERAGES THROUGH MUCH OF NEXT WEEK.
&&
.AVIATION...12/12Z
ISSUED AT 651 AM CDT FRI SEP 12 2014
WIDESPREAD MVFR TO VFR CIGS WITH RAIN ARE IN PLACE FROM SW-NE IA
AT 12Z. THESE CONDITIONS WILL CONTINUE ADVANCING SOUTH AND EAST
THROUGH THE DAY GIVING WAY TO VFR CIGS AS THE PRECIP ENDS. LATER
THIS EVENING SKIES SHOULD CLEAR...LIKELY LEADING TO VFR
OVERNIGHT. WINDS WILL BECOME LIGHT...AND THERE IS SOME POTENTIAL
FOR RADIATION FOG TO RESTRICT VSBYS...BUT CONFIDENCE IS NOT THERE
FOR INCLUSION JUST YET.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...BEERENDS
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS DES MOINES IA
333 AM CDT FRI SEP 12 2014
.SHORT TERM /TODAY/...
ISSUED AT 333 AM CDT FRI SEP 12 2014
PRECIP AND TEMP TRENDS WILL BE THE PRIMARY CONCERNS TODAY. RIGHT
ENTRANCE REGION DIVERGENCE OF STRONG 120KT JET FROM MO VALLEY INTO
SERN CANADA CONTINUES TO ENHANCE BROAD SWATH OF PRECIP FROM NE/KS
INTO THE NWRN HALF OF IA. FORCING IS MAINLY KINEMATIC AND MID LEVEL
BASED DRIVEN BY DIVERGENCE AND DPVA...AND ALTHOUGH THERE IS LITTLE
TO NO THETA-E ADVECTION BELOW 3KM...THERE DOES APPEAR TO BE FAIRLY
HIGH BASED FRONTOGENETICAL FORCING AND RESPONSE. ENHANCED SW-NE
PRECIP BANDS LINE UP FAIRLY NICELY WITH RAP H7/H5 FN DIVERGENCE AND
LOWER STATIC STABILITY NOTED BY SLIGHTLY NEGATIVE EPV IN THE SAME
LAYER. HIGH RES MODEL PRECIP DEPICTIONS ARE IN QUITE GOOD AGREEMENT
BUT LOOK SLOW AT THE MOMENT SUGGESTING PRECIP WILL MAINLY BE IN THE
MORNING...AND CERTAINLY BE EXITING TO THE EAST 21Z-00Z.
TEMPS WILL BE PROBLEMATIC WITH EXTREMELY ANOMALOUS AIRMASS JUST
UPSTREAM. BOTH THE NAEFS CLIMATOLOGICAL AND GEFS M-CLIMATE
PERCENTILES ARE IN THEIR LOWEST AND HIGHEST RESPECTIVE 1 PERCENT FOR
TEMPS AND MSLP. THIS COLD AIRMASS COMBINED WITH PRECIP WILL RESULT
IN LITTLE TEMP REBOUND TODAY AND SOME NON-DIURNAL TRENDS WITH HIGHS
NO BETTER THAN THE LOWER 50S. ALTHOUGH NOT IN THE FORECAST...WOULD
NOT BE SURPRISED TO SEE A FEW SPOTS STRUGGLE TO REACH 50F. THESE
HIGHS WOULD AGAIN BREAK MIN MAX RECORDS WHICH RANGE FROM 53-56F AT
MASON CITY...WATERLOO...DES MOINES AND OTTUMWA.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 333 AM CDT FRI SEP 12 2014
LITTLE CHANGES TO THE GOING FORECAST AS MODELS REMAIN IN AGREEMENT
BOTH FROM RUN TO RUN AND AMONG EACH OTHER. LARGE AREA OF HIGH
PRESSURE TO BUILD INTO THE STATE TONIGHT WITH DRY CONDITIONS AND
CLEARING SKIES. VERY COLD AIR FOR THIS TIME OF YEAR TO REMAIN IN
PLACE ACROSS THE REGION...WITH H85 TEMPS AROUND 0C TONIGHT AND ONLY
WARMING TO AROUND +5C THROUGH THE WEEKEND. WITH THE COOL AIR AND
HIGH PRESSURE IN PLACE TONIGHT...CLEAR SKIES AND LIGHT WINDS
TEMPERATURES EXPECTED TO DROP OFF QUITE A BIT. HOWEVER THE TEMPS MAY
BE TEMPERED SOME BY THE LINGERING MOISTURE FROM ALL THE RAIN THE
PAST FEW DAYS AND ADDITIONAL RAIN TODAY...WHICH LEADS TO BEING
SOMEWHAT HESITANT ON POTENTIAL FOR FROST FORMATION AS WELL.
THEREFORE STUCK WITH LOWS IN THE MID TO UPPER 30S AND SOME PATCHY
FROST WORDING ACROSS THE WEST/NORTH WHERE COOLEST TEMPS EXPECTED.
HIGH PRESSURE TO DOMINATE OVER THE WEEKEND...WITH TEMPS GRADUALLY
WARMING A BIT. OTHERWISE NEXT CHANCE FOR PRECIPITATION AS ANOTHER
WEAK UPPER LEVEL WAVE AND ASSOCIATED COLD FRONT DROPS THROUGH THE
REGION. ANOTHER LARGE AREA OF HIGH PRESSURE TO THEN BUILD INTO THE
CENTRAL US FOR MUCH OF NEXT WEEK. THERMAL PROFILES WARM SOME WHICH
SHOULD ALLOW TEMPERATURES TO CREEP BACK INTO THE 70S BY WEDNESDAY
INTO THURSDAY. A LARGER UPPER LEVEL WAVE THEN LOOKS TO DIG INTO THE
CENTRAL US BY NEXT FRIDAY INTO THE WEEKEND WHICH SHOULD BRING
ADDITIONAL CHANCES FOR PRECIPITATION TO MUCH OF THE AREA. EVEN WITH
THE WARMING BY THE END OF THE FORECAST PERIOD...TEMPERATURES WILL
REMAIN WELL BELOW THE SEASONAL AVERAGES THROUGH MUCH OF NEXT WEEK.
&&
.AVIATION...12/06Z
ISSUED AT 1159 PM CDT THU SEP 11 2014
CONDITIONS WILL CONTINUE TO DETERIORATE OVERNIGHT WITH CIGS AND
VSBYS DIMINISHING ESPECIALLY BETWEEN 09Z- 14Z. CIGS AND VSBYS EACH
MAY DROP TO IFR AT TIMES FRIDAY MORNING. PRECIPITATION WILL
GRADUALLY END FROM WEST TO EAST FRIDAY AFTERNOON. STRATUS LIKELY
TO LINGER THROUGH LATE AFTERNOON TO MID EVENING. THE WIND WILL
REMAIN 10KTS OR LESS THROUGH THE PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...BEERENDS
AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
208 PM CDT FRI SEP 12 2014
...UPDATED LONG TERM SECTION...
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 144 PM CDT FRI SEP 12 2014
SKIES WILL CLEAR FROM NORTH TO SOUTH EARLY TONIGHT ACROSS WESTERN
KANSAS AS SUBSIDENCE DEVELOPS BEHIND AN UPPER LEVEL TROUGH AS IT
MOVES INTO THE MISSISSIPPI VALLEY. AS SKIES CLEAR THE SURFACE
WINDS WILL BECOME LIGHT AS A SURFACE HIGH BUILDS ACROSS NORTHERN
AND CENTRAL KANSAS. MODELS TODAY ARE IN GOOD AGREEMENT WITH THE
LIGHTER WINDS NEAR THE CENTER OF THE SURFACE HIGH TO BE LOCATED
EAST OF HIGHWAY 283 BETWEEN MIDNIGHT AND 7 AM SATURDAY. BASED ON
THESE LIGHT WINDS, CLEARING SKIES, AND EXPECTED SURFACE DEW
POINTS EARLY SATURDAY MORNING WILL UNDERCUT THE COOLER MET
GUIDANCE BY A FEW DEGREES ACROSS NORTH CENTRAL AND SOUTH CENTRAL
KANSAS FOR OVERNIGHT LOWS. WILL STAY NEAR THE LATEST MET/MAV
FURTHER WEST GIVEN THE SLIGHT INCREASE IN WINDS AFTER MIDNIGHT.
THIS SOLUTION CONTINUES TO SUPPORT THE PREVIOUS FORECAST WITH LOWS
BOTTOMING OUT IN THE MID 30S TO NEAR 40 WITH THE THE COOLER
TEMPERATURES OCCURRING ACROSS NORTH CENTRAL AND PORTIONS OF WEST
CENTRAL KANSAS. SOME PATCHY FROST WILL ALSO BE POSSIBLE NORTH OF A
PRATT TO SYRACUSE LINE.
ON SATURDAY A TROUGH OF LOW PRESSURE AT THE SURFACE WILL DEVELOP
ALONG THE LEE OF THE ROCKIES AS A WESTERLY DOWN SLOPE FLOW
IMPROVES ACROSS THE CENTRAL HIGH PLAINS. SOUTHERLY WINDS WILL
INCREASE DURING THE DAY ACROSS ALL OF WESTERN KANSAS AS THE
SURFACE PRESSURES FALL ALONG THE LEE OF THE ROCKIES. IN ADDITION
TO THE INCREASING WINDS ON SATURDAY THE 850MB TEMPERATURES AT 00Z
SUNDAY WILL RANGE FROM NEAR 8C IN NORTH CENTRAL KANSAS TO 17C
ALONG THE COLORADO BORDER. THIS IS A 5C TO 10C WARM UP BETWEEN 00Z
SATURDAY TO 00Z SUNDAY. USING THIS AS A GUIDE FOR HIGHS SATURDAY
AFTERNOON THE PREVIOUS SHIFT STILL LOOKS ON TRACK WITH
TEMPERATURES CLIMBING INTO THE MID 60S TO LOWER 70S. THE WARMER
TEMPERATURES WILL BE LOCATED NEAR THE COLORADO BORDER.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 203 PM CDT FRI SEP 12 2014
THE REMNANTS OF TROPICAL STORM FENGSHEN THAT INTENSIFIED BRIEFLY
EAST OF JAPAN ON 7 SEPTEMBER RIPPLED THROUGH THE WESTERLIES AND WAS
MOVING OVER WESTERN ALASKA ON THE EAST SIDE OF AN INTENSE UPPER
LEVEL CYCLONE CENTERED NEAR 170W THIS MORNING. STRONG RIDGING WAS IN
PROGRESS FROM THE WEST COAST OF CANADA ACROSS THE NORTHWEST
TERRITORIES INTO NORTHERN ALASKA. DOWNSTREAM AMPLIFICATION OF A MEAN
LONG WAVE TROUGH IN EASTERN CANADA WAS IN PROGRESS AND LIKELY WILL
CONTINUE THROUGH MID WEEK. SEVERAL SHORT WAVE TROUGHS EMBEDDED IN
THE POLAR JET WILL MOVE OVER THE PROGRESSIVE LONG WAVE RIDGE AND DIG
INTO THE MEAN TROUGH POSITION IN THE EXTENDED PERIOD. THE LONG WAVE
RIDGE WILL WEAKEN AS THE UPPER LEVEL LOW WEST OF ALASKA OCCLUDES AND
WEAKENS AND WILL PROGRESS INTO THE WESTERN UNITED STATES EARLY NEXT
WEEK. BROAD RIDGING WILL BUILD INTO THE CENTRAL PLAINS NEXT THURSDAY
AND FRIDAY, AND ANOTHER STRONG PROGRESSIVE TROUGH WILL MOVE INTO THE
NORTHERN PLAINS LATE NEXT WEEK.
A KELVIN WAVE WAS MOVING RAPIDLY EAST THROUGH THE WESTERN HEMISPHERE
AND WAS CENTERED NEAR 120W THIS MORNING. THE NUMERICAL MODELS
SUGGEST THAT THE KELVIN WAVE WILL CONTINUE ITS EASTWARD PROGRESSION
AND ENHANCE THUNDERSTORM COVERAGE IN AFRICA BY AROUND 20 SEPTEMBER.
TROPICAL CYCLONE DEVELOPMENT WILL CONTINUE TO BE FAVORED IN THE
EASTERN PACIFIC AS THE KELVIN WAVE PASSES, AND ENHANCED HIGH LEVEL
TROPICAL MOISTURE ASSOCIATED WITH ODILE MAY MOVE INTO THE CENTRAL
PLAINS NEXT WEEKEND.
AN UPPER LEVEL TROUGH IN THE NORTHWEST TERRITORIES WILL DIG INTO THE
DAKOTAS SUNDAY, AND AN AREA OF LOW PRESSURE WILL DEEPEN IN EASTERN
COLORADO. A PLUME OF WARM AIR WILL SPREAD ACROSS WESTERN KANSAS
SUNDAY, AND TEMPERATURES WILL RISE BACK TO NEAR SEASONAL AVERAGES
SUNDAY AFTERNOON. AN ELEVATED MIXED LAYER WILL SPREAD ACROSS KANSAS
SUNDAY, AND H7 TEMPERATURES WILL BE AT LEAST 10C IN WESTERN KANSAS
SUNDAY AFTERNOON. THERE WILL BE SOME WEAK SURFACE CONVERGENCE ALONG
A WARM FRONT AS IT LIFTS NORTH ACROSS WESTERN KANSAS SUNDAY, BUT
VERY WARM TEMPERATURES ALOFT LIKELY WILL PRECLUDE DEVELOPMENT OF
THUNDERSTORMS ALONG THE BOUNDARY. THUNDERSTORMS OVER THE HIGHER
TERRAIN IN COLORADO MAY APPROACH THE KANSAS BORDER SUNDAY EVENING
BUT PROBABLY WILL BE NORTH OF HAMILTON COUNTY.
A COLD FRONT WILL MOVE INTO NORTHERN KANSAS SUNDAY NIGHT AND SHOULD
REACH MEDICINE LODGE BY LATE MORNING MONDAY. THE GFS AND GEM ARE
SLIGHTLY MORE AMPLIFIED WITH THE UPPER LEVEL TROUGH THAT DIGS
THROUGH THE NORTHERN PLAINS SUNDAY NIGHT THAN THE GFS AND ARE A
LITTLE FASTER WITH THE COLD FRONTAL PASSAGE. A NUMBER OF THE GFS
ENSEMBLE MEMBERS ARE FASTER WITH THE FRONT THAN THE OPERATIONAL RUN
AND ARE MORE IN AGREEMENT WITH THE ECMWF AND GEM. THE PREPONDERANCE
OF EVIDENCE SUPPORTS THE FASTER MOVEMENT OF THE FRONT, AND THE ECMWF
LARGELY WAS USED FOR MINOR GRID ADJUSTMENTS. THE FRONT WILL PASS
DURING THE NIGHTTIME HOURS UNDER A PLUME OF WARM TEMPERATURES ALOFT,
AND THUNDERSTORM DEVELOPMENT ALONG THE BOUNDARY LIKELY WILL BE
CONFINED TO NORTH CENTRAL AND EASTERN KANSAS WHERE MID LEVEL
TEMPERATURES ARE SLIGHTLY COOLER AND ISENTROPIC LIFTING WILL ENHANCE
UPWARD VERTICAL MOTION IN THE WARM SECTOR. WIDESPREAD STRATUS WILL
MOVE INTO WESTERN KANSAS BEHIND THE COLD FRONT AND WILL KEEP
TEMPERATURES COOL DURING THE DAY MONDAY. THERE MAY BE SOME LIGHT
SHOWERS IN THE ELEVATED FRONTOGENETIC REGION BEHIND THE SURFACE
BOUNDARY, BUT SIGNIFICANT RAINFALL IS UNLIKELY.
UPPER LEVEL RIDGING WILL BUILD TOWARD THE CENTRAL PART OF THE
COUNTRY TUESDAY THROUGH FRIDAY, AND TEMPERATURES WILL WARM INTO THE
UPPER 70S AND LOWER 80S TUESDAY. HIGHS WEDNESDAY THROUGH FRIDAY
LIKELY WILL BE IN THE UPPER 80S AND LOWER 90S. A MINOR UPPER LEVEL
TROUGH IN THE NORTHWEST FLOW ALOFT WILL MOVE FROM SOUTH DAKOTA INTO
THE MISSISSIPPI VALLEY WEDNESDAY, AND A WEAK FRONT WILL MOVE INTO
WESTERN KANSAS DURING THE DAY AND BECOME STATIONARY NEAR THE
OKLAHOMA BORDER WEDNESDAY AFTERNOON. THIS MAY PROVIDE A FOCUS FOR
DEVELOPMENT OF A FEW AFTERNOON THUNDERSTORMS AND ADDITIONAL
NOCTURNAL THUNDERSTORMS AS A MODEST LOW LEVEL JET DEVELOPS AND
ENHANCES ISENTROPIC LIFTING IN SOUTH CENTRAL KANSAS. THE BOUNDARY
MAY STILL BE WALLOWING IN KANSAS THURSDAY, AND ANOTHER ROUND OF
NOCTURNAL THUNDERSTORMS MAY OCCUR IN CENTRAL KANSAS THURSDAY NIGHT.
BY SATURDAY A COLD FRONT WILL ENTER WESTERN KANSAS AND PROVIDE
ANOTHER OPPORTUNITY FOR THUNDERSTORM DEVELOPMENT. TROPICAL HIGH
LEVEL MOISTURE FROM ODILE MAY ENHANCE RAINFALL POTENTIAL WITH THE
FRONT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1203 PM CDT FRI SEP 12 2014
AN AREA OF HIGH PRESSURE AT THE SURFACE WILL BUILD ACROSS NORTHERN
AND CENTRAL KANSAS OVERNIGHT. THIS WILL RESULT IN DECREASING
NORTHERLY WINDS THIS AFTERNOON AND LIGHT WINDS OVERNIGHT GRADUALLY
VEERING TO THE EAST/SOUTHEAST TOWARDS BY DAYBREAK ON SATURDAY.
CLEARING CONDITIONS WILL DEVELOP FROM NORTH OF SOUTH LATE TODAY
BEHIND AN UPPER LEVEL TROUGH WHICH WILL MOVE OUT OF THE NORTHERN
PLAINS LATE THIS AFTERNOON INTO THE MID/UPPER MISSISSIPPI VALLEY.
BASED ON BUFR SOUNDINGS AND HRRR MVFR CONDITIONS ARE EXPECTED TO
IMPROVE INTO THE VFR CATEGORY BETWEEN 21Z FRIDAY AND 00Z SATURDAY.
SOME PATCHY FOG WILL BE POSSIBLE AROUND DAYBREAK GIVEN CLEAR SKIES
AND LIGHT EAST/SOUTHEAST WINDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 37 67 49 79 / 0 0 10 0
GCK 36 68 49 79 / 0 0 0 0
EHA 41 72 52 80 / 0 0 10 0
LBL 39 71 53 81 / 0 0 10 0
HYS 35 64 47 77 / 0 0 10 0
P28 39 68 52 79 / 0 0 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...RUTHI
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
147 PM CDT FRI SEP 12 2014
...UPDATED SHORT TERM DISCUSSION...
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 144 PM CDT FRI SEP 12 2014
SKIES WILL CLEAR FROM NORTH TO SOUTH EARLY TONIGHT ACROSS WESTERN
KANSAS AS SUBSIDENCE DEVELOPS BEHIND AN UPPER LEVEL TROUGH AS IT
MOVES INTO THE MISSISSIPPI VALLEY. AS SKIES CLEAR THE SURFACE
WINDS WILL BECOME LIGHT AS A SURFACE HIGH BUILDS ACROSS NORTHERN
AND CENTRAL KANSAS. MODELS TODAY ARE IN GOOD AGREEMENT WITH THE
LIGHTER WINDS NEAR THE CENTER OF THE SURFACE HIGH TO BE LOCATED
EAST OF HIGHWAY 283 BETWEEN MIDNIGHT AND 7 AM SATURDAY. BASED ON
THESE LIGHT WINDS, CLEARING SKIES, AND EXPECTED SURFACE DEW
POINTS EARLY SATURDAY MORNING WILL UNDERCUT THE COOLER MET
GUIDANCE BY A FEW DEGREES ACROSS NORTH CENTRAL AND SOUTH CENTRAL
KANSAS FOR OVERNIGHT LOWS. WILL STAY NEAR THE LATEST MET/MAV
FURTHER WEST GIVEN THE SLIGHT INCREASE IN WINDS AFTER MIDNIGHT.
THIS SOLUTION CONTINUES TO SUPPORT THE PREVIOUS FORECAST WITH LOWS
BOTTOMING OUT IN THE MID 30S TO NEAR 40 WITH THE THE COOLER
TEMPERATURES OCCURRING ACROSS NORTH CENTRAL AND PORTIONS OF WEST
CENTRAL KANSAS. SOME PATCHY FROST WILL ALSO BE POSSIBLE NORTH OF A
PRATT TO SYRACUSE LINE.
ON SATURDAY A TROUGH OF LOW PRESSURE AT THE SURFACE WILL DEVELOP
ALONG THE LEE OF THE ROCKIES AS A WESTERLY DOWN SLOPE FLOW
IMPROVES ACROSS THE CENTRAL HIGH PLAINS. SOUTHERLY WINDS WILL
INCREASE DURING THE DAY ACROSS ALL OF WESTERN KANSAS AS THE
SURFACE PRESSURES FALL ALONG THE LEE OF THE ROCKIES. IN ADDITION
TO THE INCREASING WINDS ON SATURDAY THE 850MB TEMPERATURES AT 00Z
SUNDAY WILL RANGE FROM NEAR 8C IN NORTH CENTRAL KANSAS TO 17C
ALONG THE COLORADO BORDER. THIS IS A 5C TO 10C WARM UP BETWEEN 00Z
SATURDAY TO 00Z SUNDAY. USING THIS AS A GUIDE FOR HIGHS SATURDAY
AFTERNOON THE PREVIOUS SHIFT STILL LOOKS ON TRACK WITH
TEMPERATURES CLIMBING INTO THE MID 60S TO LOWER 70S. THE WARMER
TEMPERATURES WILL BE LOCATED NEAR THE COLORADO BORDER.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 302 AM CDT FRI SEP 12 2014
THIS EXTENDED PERIOD WILL BE DOMINATED BY A SERIES OF UPPER LEVEL
TROUGHS AND WAVES. THE FIRST WILL COME ALONG ABOUT LATE SUNDAY
NIGHT, DRAGGING A COLD FRONT DOWN THROUGH THE CENTRAL PLAINS WITH
IT. SATURDAY AND SUNDAY WILL GO THROUGH A SLOW WARMING TREND, WITH
MID 60S TO LOWER 70S FOR HIGHS ON SATURDAY, FOLLOWED BY HIGHS ON
SUNDAY IN THE UPPER 70S TO NEAR 80F DEGREE RANGE. THE FLOW ALOFT
DURING THE WEEKEND WILL BE ZONAL, WITH A BROAD HIGH PRESSURE RIDGE
TO OUR SOUTH AND AN UPPER TROUGH TO OUR NORTHEAST. THE IS A TROUGH
AND ASSOCIATED COLD FRONT SWEEPING DOWN FROM THE NORTH SUNDAY
NIGHT INTO MONDAY, WHICH WILL BRING A CHANCE FOR THUNDERSTORMS TO
SOUTHWESTERN KANSAS. I DID NOT GO VERY HIGH WITH POPS MONDAY,
EXCEPT FOR 30 TO 40 PERCENT IN OUR SOUTHEAST ZONES NEAR BARBER
AND PRATT COUNTIES, WHERE MOISTURE WILL BE THE GREATEST. IT WILL
ALSO BE A PRIME TIME FOR LIGHT RAIN MONDAY NIGHT, WITH THE COOLER
SURFACE AIR AND A PASSING UPPER WAVE. THIS UPPER FORCING WILL
SLIDE OFF TO THE SOUTHEAST BY TUESDAY AFTERNOON, TAKING THE
PRECIPITATION WITH IT.
THE SOUTHWEST FLOW WILL BRING WARM TEMPERATURES BACK INTO WESTERN
KANSAS WEDNESDAY. MAX TEMPERATURES BOTH WEDNESDAY AND THURSDAY
WILL REACH THE MID TO UPPER 80S, MAKING IT FEEL MORE LIKE SUMMER
AGAIN. A LEE SIDE TROUGH IN FAR WESTERN KANSAS WEDNESDAY AFTERNOON
WILL BRING A SLIGHT CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS
THERE. THERE IS ANOTHER SHORT WAVE CUTTING EAST THROUGH
SOUTHWESTERN KANSAS ON WEDNESDAY NIGHT, AND LOWER END POPS FOR
SHOWERS AND ISOLATED THUNDERSTORMS WILL EXIST WEDNESDAY NIGHT.
I ACCEPTED AND KEPT THE MIN TEMPS WHICH WERE ALREADY IN THE GRIDS,
OR THE NEW CR_EXTENDED APPLICATION GAVE. MINIMUMS WILL BASICALLY
BE IN THE 55F TO 65F DEGREE RANGE FOR THIS 3 TO 7 DAY FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1203 PM CDT FRI SEP 12 2014
AN AREA OF HIGH PRESSURE AT THE SURFACE WILL BUILD ACROSS NORTHERN
AND CENTRAL KANSAS OVERNIGHT. THIS WILL RESULT IN DECREASING
NORTHERLY WINDS THIS AFTERNOON AND LIGHT WINDS OVERNIGHT GRADUALLY
VEERING TO THE EAST/SOUTHEAST TOWARDS BY DAYBREAK ON SATURDAY.
CLEARING CONDITIONS WILL DEVELOP FROM NORTH OF SOUTH LATE TODAY
BEHIND AN UPPER LEVEL TROUGH WHICH WILL MOVE OUT OF THE NORTHERN
PLAINS LATE THIS AFTERNOON INTO THE MID/UPPER MISSISSIPPI VALLEY.
BASED ON BUFR SOUNDINGS AND HRRR MVFR CONDITIONS ARE EXPECTED TO
IMPROVE INTO THE VFR CATEGORY BETWEEN 21Z FRIDAY AND 00Z SATURDAY.
SOME PATCHY FOG WILL BE POSSIBLE AROUND DAYBREAK GIVEN CLEAR SKIES
AND LIGHT EAST/SOUTHEAST WINDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 37 67 49 79 / 0 0 10 0
GCK 36 68 49 79 / 0 0 0 0
EHA 41 72 52 80 / 0 0 10 0
LBL 39 71 53 81 / 0 0 10 0
HYS 35 64 47 77 / 0 0 10 0
P28 39 68 52 79 / 0 0 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...BURKE
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1211 PM CDT FRI SEP 12 2014
...UPDATED SYNOPSIS AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1203 PM CDT FRI SEP 12 2014
AT 12Z FRIDAY A -25C 500MB TROUGH EXTENDED FROM SOUTHEAST WYOMING
TO THE WESTERLY GREAT LAKES. A 300MB JET STRETCHED FROM NEBRASKA
TO QUEBEC. A 700MB BAROCLINIC ZONE WAS LOCATED NEAR THE RIGHT EXIT
REGION OF THIS UPPER LEVEL JET AND EXTENDED FROM EAST CENTRAL
COLORADO TO SOUTHWEST IOWA. A SURFACE TO 850MB HIGH WAS CENTERED
OVER FAR WESTERN NEBRASKA/SOUTHEAST WYOMING AT 12Z FRIDAY AND
SURFACE TEMPERATURES THIS MORNING IN THIS REGION WERE MAINLY IN
THE LOW TO MID 30S. 850MB TEMPERATURES RANGED FROM +10C AT
AMARILLO TO -1C AT NORTH PLATTE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 205 AM CDT FRI SEP 12 2014
SHORT TERM MODELS INDICATE AN UPPER LEVEL SHORTWAVE TROUGH TURNING
EASTWARD ACROSS THE CENTRAL PLAINS EARLY TODAY PROVIDING INCREASED
CHANCES FOR PRECIP ACROSS PORTIONS OF WESTERN AND CENTRAL KANSAS
THROUGH MID DAY. AS THE SHORTWAVE TRANSITIONS THROUGH, A STRONG
+90KT UPPER LEVEL JET WITH A RIGHT FRONT ENTRANCE REGION SET UP
ACROSS CENTRAL AND PORTIONS OF WESTERN KANSAS, WILL GRADUALLY
SHIFT EASTWARD THROUGH THIS AFTERNOON. MEANWHILE, THE NAM AND GFS
SHOW H7 FRONTOGENETIC BANDING MIGRATING EASTWARD ACROSS WESTERN
KANSAS THIS MORNING IN WAKE OF SECONDARY FRONT PUSHING SOUTH
ACROSS THE AREA. AS A RESULT, ONGOING SCATTERED SHOWERS MOVING
EAST ACROSS WESTERN KANSAS EARLY THIS MORNING WILL TRACK FURTHER
EAST INTO CENTRAL KANSAS THROUGH LATE MORNING WITH ANY LINGERING
PRECIP COMING TO AN END WEST TO EAST BY THIS AFTERNOON. DRIER
CONDITIONS ARE THEN EXPECTED ACROSS WESTERN KANSAS FRIDAY NIGHT AS
THE UPPER LEVEL SHORTWAVE LIFTS NORTHEAST INTO THE GREAT LAKES
REGION.
TEMPERATURES WILL REMAIN WELL BELOW NORMAL TODAY AS A SECONDARY
SURGE OF COOLER AIR MOVES SOUTHWARD INTO WESTERN KANSAS AHEAD OF A
BROAD SURFACE HIGH EDGING SOUTHEAST INTO THE CENTRAL PLAINS. THE
REINFORCED COOLER AIR MASS COMBINED WITH LINGERING PRECIP AND A
PREVAILING STRATUS DECK WILL KEEP TEMPERATURES FROM CLIMBING ABOVE
THE LOWER TO MID 50S(F) TODAY WITH TEMPERATURES LIKELY FALLING
INTO THE 40S(F) IN SOME LOCATIONS BY THIS AFTERNOON AS THE COLDER
AIR SETTLES IN. FOR TONIGHT, SURFACE HIGH PRESSURE ACROSS WESTERN
KANSAS WILL KEEP THE MUCH COOLER AIR MASS LOCKED IN PLACE ACROSS
WESTERN KANSAS. ALONG WITH THE HELP OF LIGHTER WINDS AND CLEARING
SKIES, LOOK FOR LOWS DROPPING DOWN INTO THE MID TO UPPER 30S(F)
ACROSS MUCH OF CENTRAL AND SOUTHWEST KANSAS WITH NEAR 40F STILL
POSSIBLE CLOSER TO THE OKLAHOMA BORDER. WITH AMPLE RESIDUAL
MOISTURE PRESENT, THE POTENTIAL FOR FROST DEVELOPMENT WILL EXIST
EARLY SATURDAY MORNING ACROSS WEST CENTRAL AND CENTRAL KANSAS AND
POSSIBLY FURTHER SOUTH INTO NORTHERN PORTIONS OF SOUTHWEST KANSAS.
FROST HEADLINES MAY NEED TO BE CONSIDERED BY THE FOLLOWING SHIFT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 302 AM CDT FRI SEP 12 2014
THIS EXTENDED PERIOD WILL BE DOMINATED BY A SERIES OF UPPER LEVEL
TROUGHS AND WAVES. THE FIRST WILL COME ALONG ABOUT LATE SUNDAY
NIGHT, DRAGGING A COLD FRONT DOWN THROUGH THE CENTRAL PLAINS WITH
IT. SATURDAY AND SUNDAY WILL GO THROUGH A SLOW WARMING TREND, WITH
MID 60S TO LOWER 70S FOR HIGHS ON SATURDAY, FOLLOWED BY HIGHS ON
SUNDAY IN THE UPPER 70S TO NEAR 80F DEGREE RANGE. THE FLOW ALOFT
DURING THE WEEKEND WILL BE ZONAL, WITH A BROAD HIGH PRESSURE RIDGE
TO OUR SOUTH AND AN UPPER TROUGH TO OUR NORTHEAST. THE IS A TROUGH
AND ASSOCIATED COLD FRONT SWEEPING DOWN FROM THE NORTH SUNDAY
NIGHT INTO MONDAY, WHICH WILL BRING A CHANCE FOR THUNDERSTORMS TO
SOUTHWESTERN KANSAS. I DID NOT GO VERY HIGH WITH POPS MONDAY,
EXCEPT FOR 30 TO 40 PERCENT IN OUR SOUTHEAST ZONES NEAR BARBER
AND PRATT COUNTIES, WHERE MOISTURE WILL BE THE GREATEST. IT WILL
ALSO BE A PRIME TIME FOR LIGHT RAIN MONDAY NIGHT, WITH THE COOLER
SURFACE AIR AND A PASSING UPPER WAVE. THIS UPPER FORCING WILL
SLIDE OFF TO THE SOUTHEAST BY TUESDAY AFTERNOON, TAKING THE
PRECIPITATION WITH IT.
THE SOUTHWEST FLOW WILL BRING WARM TEMPERATURES BACK INTO WESTERN
KANSAS WEDNESDAY. MAX TEMPERATURES BOTH WEDNESDAY AND THURSDAY
WILL REACH THE MID TO UPPER 80S, MAKING IT FEEL MORE LIKE SUMMER
AGAIN. A LEE SIDE TROUGH IN FAR WESTERN KANSAS WEDNESDAY AFTERNOON
WILL BRING A SLIGHT CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS
THERE. THERE IS ANOTHER SHORT WAVE CUTTING EAST THROUGH
SOUTHWESTERN KANSAS ON WEDNESDAY NIGHT, AND LOWER END POPS FOR
SHOWERS AND ISOLATED THUNDERSTORMS WILL EXIST WEDNESDAY NIGHT.
I ACCEPTED AND KEPT THE MIN TEMPS WHICH WERE ALREADY IN THE GRIDS,
OR THE NEW CR_EXTENDED APPLICATION GAVE. MINIMUMS WILL BASICALLY
BE IN THE 55F TO 65F DEGREE RANGE FOR THIS 3 TO 7 DAY FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1203 PM CDT FRI SEP 12 2014
AN AREA OF HIGH PRESSURE AT THE SURFACE WILL BUILD ACROSS NORTHERN
AND CENTRAL KANSAS OVERNIGHT. THIS WILL RESULT IN DECREASING
NORTHERLY WINDS THIS AFTERNOON AND LIGHT WINDS OVERNIGHT GRADUALLY
VEERING TO THE EAST/SOUTHEAST TOWARDS BY DAYBREAK ON SATURDAY.
CLEARING CONDITIONS WILL DEVELOP FROM NORTH OF SOUTH LATE TODAY
BEHIND AN UPPER LEVEL TROUGH WHICH WILL MOVE OUT OF THE NORTHERN
PLAINS LATE THIS AFTERNOON INTO THE MID/UPPER MISSISSIPPI VALLEY.
BASED ON BUFR SOUNDINGS AND HRRR MVFR CONDITIONS ARE EXPECTED TO
IMPROVE INTO THE VFR CATEGORY BETWEEN 21Z FRIDAY AND 00Z SATURDAY.
SOME PATCHY FOG WILL BE POSSIBLE AROUND DAYBREAK GIVEN CLEAR SKIES
AND LIGHT EAST/SOUTHEAST WINDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 50 38 67 49 / 70 0 0 10
GCK 49 35 68 49 / 70 0 0 0
EHA 49 42 72 52 / 70 0 0 10
LBL 52 41 71 53 / 70 0 0 10
HYS 50 37 64 47 / 60 0 0 10
P28 55 42 68 52 / 50 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...JJOHNSON
LONG TERM...BURKE
AVIATION...BURGERT
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
215 AM EDT FRI SEP 12 2014
.UPDATE...
ISSUED AT 1252 AM EDT FRI SEP 12 2014
SPOTTY LIGHT RADAR RETURNS ARE SHOWING UP ACROSS LOCATIONS ALONG AND
SOUTH OF THE MOUNTAIN PARKWAY. THE LATEST HRRR TRENDS SUPPORT THE
CONTINUATION OF AT LEAST ISOLATED LIGHT RAIN/SHOWERS THROUGH DAWN...
AND GIVEN THE DEEP MOISTURE STILL IN PLACE...SEE NO REASON TO ARGUE.
HAVE EXPANDED THE ISOLATED POPS BACK TOWARDS THE I-64 CORRIDOR
THROUGH DAWN. THE REST OF THE FORECAST REMAINS ON TRACK.
UPDATE ISSUED AT 1039 PM EDT THU SEP 11 2014
UPDATED TO REMOVE THE HIGHER POPS FROM THE FORECAST AS RAIN SHOWERS
HAVE DIMINISHED ACROSS SOUTHEAST KENTUCKY. ISOLATED SHOWERS MAY STILL
BE POSSIBLE OVER THE NEXT HOUR...BUT WE SHOULD SEE A FAIRLY QUIET
SECOND HALF OF THE NIGHT. GIVEN THE PRESENCE OF THE WASHED OUT
BOUNDARY ACROSS OUR SOUTHERN AREAS...PLAN TO BRING SOME ISOLATED
SHOWERS BACK INTO THE FORECAST TOWARDS DAWN WITH THE ABUNDANCE OF
MOISTURE LOCATED ALONG THE FRONT. THIS COULD MANIFEST ITSELF MORE AS
DRIZZLE...BUT REGARDLESS...SOME POPS ARE WARRANTED.
OTHERWISE...HOURLY GRIDS SEEM PRETTY GOOD.
UPDATE ISSUED AT 727 PM EDT THU SEP 11 2014
UPDATED TO REMOVE THE LAST OF THE THUNDER. STILL WATCHING AN INTENSE
BAND OF SHOWERS AS THEY MOVE SOUTH ACROSS SOUTHEAST KENTUCKY. THESE
ARE PEGGED TO CLEAR THE SOUTHEAST COUNTIES BY 10 PM. THE REST OF THE
NIGHT SHOULD THEN FEATURE DRIER WEATHER. LOOKS LIKE STRATUS SHOULD
BUILD IN BEHIND THE STALLING COLD FRONT. IT IS POSSIBLE WE COULD SEE
A LITTLE DRIZZLE IF THE MOISTURE DEPTH CAN INCREASE ENOUGH. CERTAINLY
ENOUGH OF A THREAT TO LEAVE SOME SMALL POPS IN LATE TONIGHT. CLOUDS
WILL HOLD TOUGH THROUGH THE NIGHT AND MAY HOLD ON THROUGH MUCH OF THE
DAY TOMORROW AS WINDS TURN NORTH-NORTHEASTERLY...HELPING TO MAINTAIN
THE LOW CLOUDS. WITH THE CLOUDS...IT SHOULD HELP CUT DOWN ON THE FOG
POTENTIAL TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 400 PM EDT THU SEP 11 2014
A LINE OF CONVECTION DEVELOPED AND MOVED THROUGH SE KENTUCKY THIS
AFTERNOON. THE EFFECTIVE COLD FRONT APPEARS TO BE WITH THIS LINE. A
FEW SHOWERS HAVE DEVELOPED TO THE NW...BUT PRECIP HAS BEEN SPARSE.
MODELS HAVE NOT HANDLED THIS VERY WELL. IN LIGHT OF TRENDS...HAVE
GONE BELOW MODEL GUIDANCE FOR POPS OVER MUCH OF THE AREA FOR TONIGHT.
EVEN BEHIND THE FRONT...MOISTURE WILL LINGER...AND ADDITIONAL SHOWERS
CAN NOT BE RULED OUT ON FRIDAY OR FRIDAY NIGHT. A SHORTWAVE TROUGH
PASSING ACROSS THE GREAT LAKES MAY ALSO ENHANCE OUR POP ON FRIDAY
NIGHT BEFORE DRIER AIR FINALLY ARRIVES IN ITS WAKE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 354 PM EDT THU SEP 11 2014
MID TERM MODELS ARE STILL IN GOOD AGREEMENT FOR THE UPPER LEVEL LONG
WAVE PATTERN. A CLOSED LOW WILL BE PASSING ALONG THE UPPER GREAT
LAKES AT THE START OF THE FORECAST PERIOD...QUICKLY MOVING EASTWARD
AND LOSING STRENGTH. MEANWHILE...AN UPPER LEVEL RIDGE ACROSS THE
SOUTHERN CONUS WILL KEEP A GOOD TRANSITION ZONE OVER THE OHIO RIVER
VALLEY WITH STRONG WRLY FLOW. THIS SHORTWAVE/CLOSED LOW WILL CAUSE A
DISTURBANCE AT THE SURFACE...WITH A STRONG AREA OF QVECTOR
CONVERGENCE EXPECTED TO MOVE ACROSS THE UPPER GREAT LAKES REGION AS
WELL BY THE START OF THE FORECAST PERIOD. KY WILL FIND ITSELF ON THE
SOUTHERN FRINGES OF THIS DISTURBANCE...EXITING AS WE HEAD INTO 12Z
SATURDAY. AS IT QUICKLY PUSHES OFF TO THE EAST DURING THE DAY...ANY
PRECIP CHANCES WILL CEASE ACROSS FAR SE KY BY LATE SAT AFTERNOON.
MODELS ARE CONTINUING TO SUPPORT A FASTER EXIT OF PRECIPITATION
COMPARED TO THAT OF PREVIOUS RUNS FOR DURING THE DAY SATURDAY. CUT
BACK POPS SLIGHTLY...WITH ALL RAIN EXITING KY BY 0Z SUNDAY. THE
BOUNDARY WILL BECOME STALLED OUT ONCE MORE TO OUR SOUTH...NEAR THE
ATLANTIC COAST. HOWEVER...WITH THE INFLUX OF MOISTURE FROM THE
ATLANTIC...DAYTIME INSTABILITY WILL HELP PRECIP CHANCES SPREAD
FARTHER NORTH...POSSIBLY MAKING IT TO THE FAR SE BORDER OF KY DURING
THE DAY SUNDAY. PREVIOUS FORECAST LEFT MENTION OF PRECIP OUT
ALONG THE BORDER. HOWEVER...LATEST MODEL RUNS ARE ALL IN VERY
GOOD AGREEMENT THAT POPS MOVE CLOSE ENOUGH TO OUR BORDER THAT
CONFIDENCE ERORRED ON THE SIDE AT LEAST INCLUDING SOME SLIGHT CHANCE
POPS FOR THE HIGH TERRAIN ALONG THE TN/VA BORDER. THE SAME APPLIES
FOR DURING THE DAY MONDAY....ALTHOUGH MODELS ARE GOOD AGREEMENT OF
THE PRECIP SPREADING FARTHER INTO THE CWA DURING THE DAY AS THE
BOUNDARY SHIFTS SLIGHTLY NORTHWARD.
MEANWHILE MONDAY...ANOTHER SHORTWAVE WILL DEVELOP IN THE LONGWAVE
PATTERN...DROPPING HEIGHTS SLIGHTLY ACROSS EASTERN KY AND BRINGING
YET ANOTHER QUICK MOVING BUT WEAK SURFACE COLD FRONT THAT WILL SWEEP
THROUGH KY LATE MONDAY NIGHT. ONCE AGAIN...ERN KY WILL FIND ITSELF
ON THE SOUTHERN FRINGES OF THIS DISTURBANCE...BUT THE BOUNDARY
SHOULD INTERACT ENOUGH WITH THE ONGOING PRECIP IN THE SE TO KEEP
POPS GOING THROUGHOUT MOST OF THE NIGHT MONDAY NIGHT AS WELL. STRONG
SUBSIDENCE WILL MOVE IN BEHIND THE FRONTAL BOUNDARY...WITH POPS
QUICKLY TAPERING OFF BY EARLY TUESDAY. WIDESPREAD CLOUD COVER WILL
ALSO ACCOMPANY THIS SYSTEM...SLOWLY CLEARING THROUGHOUT THE DAY
TUESDAY. HIGH PRESSURE...ONCE IN CONTROL...SHOULD STAY FOR THE
REMAINDER OF THE FORECAST PERIOD...WITH EASTERN KY FINALLY EXPECTED
TO HAVE A BREAK FROM THE PRECIP FROM TUESDAY THROUGH THURSDAY.
OVERALL...STRONG ZONAL FLOW ACROSS KY WILL KEEP TEMPERATURES
MODERATED IN THE MID 70S THROUGH MUCH OF THE EXTENDED FORECAST.
OVERNIGHT LOWS WILL BE CLOUD DEPENDENT. FOR THOSE NIGHTS WHEN
CLEARING IS EXPECTED...LOWS COULD DROP DOWN INTO THE CHILLY LOW TO
MID 50S. AND WHEN THERE IS CLOUD COVER INVOLVED...AS IS THE CASE IN
THE SE FOR MUCH OF THE EXTENDED...UPPER 50S AND LOW 60S WILL BE
THE RANGE TO LOOK FOR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 215 AM EDT FRI SEP 12 2014
IFR TO MVFR STRATUS WILL BE THE RULE ACROSS MOST OF EASTERN KENTUCKY
THROUGH THE PERIOD...ALTHOUGH A FEW PASSING AREAS OF LIGHT
RAIN/SHOWERS MAY IMPROVE CEILINGS TEMPORARILY. WINDS WILL REMAIN
OUT OF THE NORTH AND NORTHEAST AT AROUND 5 KTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...HAL
LONG TERM...JMW
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1253 AM EDT FRI SEP 12 2014
.UPDATE...
ISSUED AT 1252 AM EDT FRI SEP 12 2014
SPOTTY LIGHT RADAR RETURNS ARE SHOWING UP ACROSS LOCATIONS ALONG AND
SOUTH OF THE MOUNTAIN PARKWAY. THE LATEST HRRR TRENDS SUPPORT THE
CONTINUATION OF AT LEAST ISOLATED LIGHT RAIN/SHOWERS THROUGH DAWN...
AND GIVEN THE DEEP MOISTURE STILL IN PLACE...SEE NO REASON TO ARGUE.
HAVE EXPANDED THE ISOLATED POPS BACK TOWARDS THE I-64 CORRIDOR
THROUGH DAWN. THE REST OF THE FORECAST REMAINS ON TRACK.
UPDATE ISSUED AT 1039 PM EDT THU SEP 11 2014
UPDATED TO REMOVE THE HIGHER POPS FROM THE FORECAST AS RAIN SHOWERS
HAVE DIMINISHED ACROSS SOUTHEAST KENTUCKY. ISOLATED SHOWERS MAY STILL
BE POSSIBLE OVER THE NEXT HOUR...BUT WE SHOULD SEE A FAIRLY QUIET
SECOND HALF OF THE NIGHT. GIVEN THE PRESENCE OF THE WASHED OUT
BOUNDARY ACROSS OUR SOUTHERN AREAS...PLAN TO BRING SOME ISOLATED
SHOWERS BACK INTO THE FORECAST TOWARDS DAWN WITH THE ABUNDANCE OF
MOISTURE LOCATED ALONG THE FRONT. THIS COULD MANIFEST ITSELF MORE AS
DRIZZLE...BUT REGARDLESS...SOME POPS ARE WARRANTED.
OTHERWISE...HOURLY GRIDS SEEM PRETTY GOOD.
UPDATE ISSUED AT 727 PM EDT THU SEP 11 2014
UPDATED TO REMOVE THE LAST OF THE THUNDER. STILL WATCHING AN INTENSE
BAND OF SHOWERS AS THEY MOVE SOUTH ACROSS SOUTHEAST KENTUCKY. THESE
ARE PEGGED TO CLEAR THE SOUTHEAST COUNTIES BY 10 PM. THE REST OF THE
NIGHT SHOULD THEN FEATURE DRIER WEATHER. LOOKS LIKE STRATUS SHOULD
BUILD IN BEHIND THE STALLING COLD FRONT. IT IS POSSIBLE WE COULD SEE
A LITTLE DRIZZLE IF THE MOISTURE DEPTH CAN INCREASE ENOUGH. CERTAINLY
ENOUGH OF A THREAT TO LEAVE SOME SMALL POPS IN LATE TONIGHT. CLOUDS
WILL HOLD TOUGH THROUGH THE NIGHT AND MAY HOLD ON THROUGH MUCH OF THE
DAY TOMORROW AS WINDS TURN NORTH-NORTHEASTERLY...HELPING TO MAINTAIN
THE LOW CLOUDS. WITH THE CLOUDS...IT SHOULD HELP CUT DOWN ON THE FOG
POTENTIAL TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 400 PM EDT THU SEP 11 2014
A LINE OF CONVECTION DEVELOPED AND MOVED THROUGH SE KENTUCKY THIS
AFTERNOON. THE EFFECTIVE COLD FRONT APPEARS TO BE WITH THIS LINE. A
FEW SHOWERS HAVE DEVELOPED TO THE NW...BUT PRECIP HAS BEEN SPARSE.
MODELS HAVE NOT HANDLED THIS VERY WELL. IN LIGHT OF TRENDS...HAVE
GONE BELOW MODEL GUIDANCE FOR POPS OVER MUCH OF THE AREA FOR TONIGHT.
EVEN BEHIND THE FRONT...MOISTURE WILL LINGER...AND ADDITIONAL SHOWERS
CAN NOT BE RULED OUT ON FRIDAY OR FRIDAY NIGHT. A SHORTWAVE TROUGH
PASSING ACROSS THE GREAT LAKES MAY ALSO ENHANCE OUR POP ON FRIDAY
NIGHT BEFORE DRIER AIR FINALLY ARRIVES IN ITS WAKE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 354 PM EDT THU SEP 11 2014
MID TERM MODELS ARE STILL IN GOOD AGREEMENT FOR THE UPPER LEVEL LONG
WAVE PATTERN. A CLOSED LOW WILL BE PASSING ALONG THE UPPER GREAT
LAKES AT THE START OF THE FORECAST PERIOD...QUICKLY MOVING EASTWARD
AND LOSING STRENGTH. MEANWHILE...AN UPPER LEVEL RIDGE ACROSS THE
SOUTHERN CONUS WILL KEEP A GOOD TRANSITION ZONE OVER THE OHIO RIVER
VALLEY WITH STRONG WRLY FLOW. THIS SHORTWAVE/CLOSED LOW WILL CAUSE A
DISTURBANCE AT THE SURFACE...WITH A STRONG AREA OF QVECTOR
CONVERGENCE EXPECTED TO MOVE ACROSS THE UPPER GREAT LAKES REGION AS
WELL BY THE START OF THE FORECAST PERIOD. KY WILL FIND ITSELF ON THE
SOUTHERN FRINGES OF THIS DISTURBANCE...EXITING AS WE HEAD INTO 12Z
SATURDAY. AS IT QUICKLY PUSHES OFF TO THE EAST DURING THE DAY...ANY
PRECIP CHANCES WILL CEASE ACROSS FAR SE KY BY LATE SAT AFTERNOON.
MODELS ARE CONTINUING TO SUPPORT A FASTER EXIT OF PRECIPITATION
COMPARED TO THAT OF PREVIOUS RUNS FOR DURING THE DAY SATURDAY. CUT
BACK POPS SLIGHTLY...WITH ALL RAIN EXITING KY BY 0Z SUNDAY. THE
BOUNDARY WILL BECOME STALLED OUT ONCE MORE TO OUR SOUTH...NEAR THE
ATLANTIC COAST. HOWEVER...WITH THE INFLUX OF MOISTURE FROM THE
ATLANTIC...DAYTIME INSTABILITY WILL HELP PRECIP CHANCES SPREAD
FARTHER NORTH...POSSIBLY MAKING IT TO THE FAR SE BORDER OF KY DURING
THE DAY SUNDAY. PREVIOUS FORECAST LEFT MENTION OF PRECIP OUT
ALONG THE BORDER. HOWEVER...LATEST MODEL RUNS ARE ALL IN VERY
GOOD AGREEMENT THAT POPS MOVE CLOSE ENOUGH TO OUR BORDER THAT
CONFIDENCE ERRED ON THE SIDE AT LEAST INCLUDING SOME SLIGHT CHANCE
POPS FOR THE HIGH TERRAIN ALONG THE TN/VA BORDER. THE SAME APPLIES
FOR DURING THE DAY MONDAY....ALTHOUGH MODELS ARE GOOD AGREEMENT OF
THE PRECIP SPREADING FARTHER INTO THE CWA DURING THE DAY AS THE
BOUNDARY SHIFTS SLIGHTLY NORTHWARD.
MEANWHILE MONDAY...ANOTHER SHORTWAVE WILL DEVELOP IN THE LONGWAVE
PATTERN...DROPPING HEIGHTS SLIGHTLY ACROSS EASTERN KY AND BRINGING
YET ANOTHER QUICK MOVING BUT WEAK SURFACE COLD FRONT THAT WILL SWEEP
THROUGH KY LATE MONDAY NIGHT. ONCE AGAIN...ERN KY WILL FIND ITSELF
ON THE SOUTHERN FRINGES OF THIS DISTURBANCE...BUT THE BOUNDARY
SHOULD INTERACT ENOUGH WITH THE ONGOING PRECIP IN THE SE TO KEEP
POPS GOING THROUGHOUT MOST OF THE NIGHT MONDAY NIGHT AS WELL. STRONG
SUBSIDENCE WILL MOVE IN BEHIND THE FRONTAL BOUNDARY...WITH POPS
QUICKLY TAPERING OFF BY EARLY TUESDAY. WIDESPREAD CLOUD COVER WILL
ALSO ACCOMPANY THIS SYSTEM...SLOWLY CLEARING THROUGHOUT THE DAY
TUESDAY. HIGH PRESSURE...ONCE IN CONTROL...SHOULD STAY FOR THE
REMAINDER OF THE FORECAST PERIOD...WITH EASTERN KY FINALLY EXPECTED
TO HAVE A BREAK FROM THE PRECIP FROM TUESDAY THROUGH THURSDAY.
OVERALL...STRONG ZONAL FLOW ACROSS KY WILL KEEP TEMPERATURES
MODERATED IN THE MID 70S THROUGH MUCH OF THE EXTENDED FORECAST.
OVERNIGHT LOWS WILL BE CLOUD DEPENDENT. FOR THOSE NIGHTS WHEN
CLEARING IS EXPECTED...LOWS COULD DROP DOWN INTO THE CHILLY LOW TO
MID 50S. AND WHEN THERE IS CLOUD COVER INVOLVED...AS IS THE CASE IN
THE SE FOR MUCH OF THE EXTENDED...UPPER 50S AND LOW 60S WILL BE
RANGE TO LOOK FOR.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 727 PM EDT THU SEP 11 2014
LOW CLOUDS WILL CONTINUE TO SPREAD SOUTH INTO EASTERN KENTUCKY BEHIND
A DEPARTING COLD FRONT. THIS WILL SET THE STAGE FOR IFR TO MVFR CIGS
THROUGH THE OVERNIGHT HOURS. BY LATE TONIGHT...MOST AREAS SHOULD BE
IFR OR VERY LOW MVFR. SOME GRADUAL IMPROVEMENT WILL BE SEEN AS WE
HEAD THROUGH THE DAYLIGHT HOURS TOMORROW...BUT WE WILL STRUGGLE TO
GET OUT OF THE MVFR CATEGORY. WINDS WILL REMAIN LIGHT OUT OF THE
NORTH TO NORTHEAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...HAL
LONG TERM...JMW
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
348 PM CDT FRI SEP 12 2014
.DISCUSSION...
OUR WEAK COLD FRONT REMAINS STATIONARY JUST S OF THE I-20 CORRIDOR
OF E TX/N LA THIS AFTERNOON...WITH A LARGE SUCKER HOLE RECENTLY
OPENING UP ACROSS NW LA. TEMPS IN THESE AREAS HAVE WARMED INTO THE
LOWER/MID 80S THIS AFTERNOON...BUT TEMPS REMAIN MUCH COOLER UNDER
THE LOW STRATUS FARTHER W AND N. AS EXPECTED...SCT CONVECTION HAS
DEVELOPED ALONG THE FRONTAL ZONE OVER DEEP E TX...WITH THE WEAK
SEABREEZE APPROACHING THIS AREA AS WELL AS WCNTRL LA FROM SE TX/SW
LA. BELIEVE THAT THIS CONVECTION WILL CONTINUE THROUGH A PORTION
OF THIS EVENING BEFORE DIMINISHING WITH THE LOSS OF
HEATING/INSTABILITY...WITH THE FRONTAL BNDRY EXPECTED TO SLOWLY
DRIFT BACK S ACROSS THIS AREA AND THE SRN SECTIONS OF NCNTRL LA
THIS EVENING/OVERNIGHT. THE HRRR AND TO SOME EXTENT...THE 12Z WRF
DOES INDICATE THE ONGOING CONVECTION POSSIBLY BUILDING BACK A
LITTLE FARTHER NNE TO NEAR/JUST S OF THE I-20 CORRIDOR OF E TX/NW
LA THIS EVENING...WITH ONLY ISOLATED -SHRA EXPECTED FARTHER N
CLOSER TO THE WEAK 850MB TROUGH AS IT REMAINS JUST N OF THE REGION
OVER SE OK/WRN AND CNTRL AR. DID MAINTAIN HIGH CHANCE POPS FOR
AREAS NEAR/S OF THE FRONT THIS EVENING...LOWERING POPS A TAD LATE
AS THE CONVECTION SHOULD WANE ONCE OVERALL FORCING WEAKENS. SHOULD
SEE A WIDE RANGE IN MIN TEMPS OVERNIGHT GIVEN THE SHALLOW NATURE
OF THE POST-FRONTAL AIR MASS...WITH TEMPS POSSIBLY FALLING INTO
THE UPPER 50S OVER SE OK/SW AR.
THE WEAK COLD FRONT IS EXPECTED TO NEAR THE COAST AROUND 12Z
SATURDAY...WITH THE POST-FRONTAL STRATUS HOLDING TOUGH THROUGH THE
DAY. GIVEN THE DEPTH OF THE MOISTURE IN PLACE...DID INSERT SLIGHT
CHANCE POPS AREAWIDE SATURDAY AS ANY WEAK FORCING WILL EASILY
RESULT IN -SHRA DEVELOPMENT...WITH DAYTIME TEMPS ONLY RISING 10
DEGREES OR SO FROM THE MORNING LOWS. THE LOW STRATUS SHOULD BEGIN
TO SLOWLY LIFT SUNDAY...POSSIBLY SCATTERING OUT IN THE AFTERNOON
OVER PORTIONS OF THE REGION. THIS SHOULD RESULT IN MODERATING
TEMPS...ALTHOUGH SFC RIDGING IN PLACE WILL MAINTAIN ABNORMALLY LOW
DEWPOINTS AND COMFORTABLE RH/S FOR THIS TIME OF YEAR. SHOULD BEGIN
TO SEE A RETURN OF HIGHER RH/S BY TUESDAY AS THE BROAD UPPER LEVEL
LOW/TROPICAL WAVE...NOW OVER SRN FL...BEGINS TO SHIFT W ACROSS THE
GULF OF MX THIS WEEKEND AND POSSIBLY IMPACT THE TX COAST.
ATTM...ENOUGH SHEAR ALOFT SHOULD KEEP THIS SYSTEM FROM
INTENSIFYING THIS WEEKEND AND EARLY NEXT WEEK...ALTHOUGH IT WILL
HELP ENHANCE THE SEABREEZE AS IT MOVES INLAND ACROSS SE AND DEEP E
TX/SRN AND CNTRL LA TUESDAY. IN ADDITION...A SHORTWAVE IN THE NW
FLOW ALOFT WILL DROP SE ACROSS THE REGION TUESDAY AS WELL...WHICH
COULD FURTHER ENHANCE FORCING OVER THE SRN SECTIONS OF THE REGION.
HAVE INCREASED POPS TO MID CHANCE S OF I-20 TUESDAY...WITH
CONVECTION DIMINISHING TUESDAY NIGHT/WEDNESDAY AS DRIER AIR ALOFT
MIXES SE IN WAKE OF THIS SHORTWAVE. A DRY NW FLOW LOOKS TO PERSIST
THROUGHOUT THE REMAINDER OF THE WEEK AS UPPER LEVEL RIDGING BUILDS
OVER THE DESERT SW AND THE ROCKIES. TEMPS SHOULD BE NEAR CLIMO
THROUGH THE PERIOD AS WELL.
PRELIMS TO FOLLOW BELOW...
15
&&
.PREV DISCUSSION... /ISSUED 1222 PM CDT FRI SEP 12 2014/
AVIATION...
IFR CEILINGS ABOUND AT ALL SITES EXCEPT FOR LFK...FOR THEY ARE
VERY NEAR THE COLD FRONT BOUNDARY. DO NOT EXPECT CONDITIONS TO
IMPROVE MUCH THIS FORECAST PERIOD AS THE MOISTURE OVERRUNNING THE
FRONT WILL STAY IN PLACE UNTIL SATURDAY. /35/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 65 76 61 85 66 / 30 20 10 10 10
MLU 65 77 61 84 65 / 30 20 10 10 10
DEQ 59 71 57 79 62 / 30 20 10 10 10
TXK 60 72 58 81 63 / 30 20 10 10 10
ELD 61 74 57 81 62 / 30 20 10 10 10
TYR 63 74 61 85 68 / 40 20 10 10 10
GGG 65 75 61 85 66 / 40 20 10 10 10
LFK 69 80 64 88 68 / 50 30 10 10 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
15
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1222 PM CDT FRI SEP 12 2014
.AVIATION...
IFR CEILINGS ABOUND AT ALL SITES EXCEPT FOR LFK...FOR THEY ARE
VERY NEAR THE COLD FRONT BOUNDARY. DO NOT EXPECT CONDITIONS TO
IMPROVE MUCH THIS FORECAST PERIOD AS THE MOISTURE OVERRUNNING THE
FRONT WILL STAY IN PLACE UNTIL TOMORROW. /35/
&&
.PREV DISCUSSION... /ISSUED 1153 AM CDT FRI SEP 12 2014/
DISCUSSION...
A WEAK COLD FRONT REMAINS DRAPED FROM W TO E ACROSS THE REGION
THIS MORNING...AND SHOWS UP WELL VIA THE LOW STRATUS FIELD ON THE
VISIBLE SATELLITE IMAGERY. THE LEADING EDGE OF THIS BNDRY EXTENDS
FROM NEAR A ACT...TO PSN/JSO...TO RFI...THEN SE TO NEAR A IER TO
ESF LINE AS OF 16Z...WITH THE SHORT TERM PROGS HOLDING IT NEARLY
STATIONARY THROUGH THE AFTERNOON BEFORE SLOWLY MIXING IT S JUST
BEFORE SUNSET. MEANWHILE...SCT TO NUMEROUS AREAS OF SHRA WITH
EMBEDDED TSRA CONTINUE N OF THE FRONT ACROSS EXTREME NE TX/SW
AR/SE OK...WHERE 850MB THETA-E RIDGING HAS DEVELOPED JUST AHEAD OF
THE 850MB TROUGH OVER SE OK/SW AR. THIS RAINFALL IS BEING FURTHER
ENHANCED FROM ELEVATED MOISTURE FROM TS ODILE ALONG THE WRN MX
COAST...WHICH IS ROUNDING THE FLAT UPPER RIDGING OVER SE TX/GULF
COAST REGION. FORTUNATELY...RAINFALL RATES HAVE NOT BEEN
EXCESSIVELY HEAVY THIS MORNING BUT LOOKS TO PERSIST THROUGH AT
LEAST MID-AFTERNOON /PER THE 12Z PROGS AND LATEST HRRR RUNS/
BEFORE DIMINISHING. MEANWHILE...A WEAK SEABREEZE OVER SE TX/SW LA
IS BEING ENHANCED BY AN UPPER LOW OVER ERN OLD MX...WITH SCT
CONVECTION HAVING ALREADY DEVELOPED ALONG THE COAST. VISIBLE
SATELLITE IMAGE INDICATES THAT TOWERS HAVE DEVELOPED JUST AHEAD OF
THE FRONT OVER DEEP E TX/WCNTRL LA...WITH 2500-3000 J/KG OF SBCAPE
HAVING DEVELOPED. DEEP LAYER SHEAR REMAINS QUITE WEAK...THUS THE
CONVECTION SHOULD BE PULSY BUT STILL CAPABLE OF BRIEF DOWNPOURS
GIVEN THE PW/S IN EXCESS OF 2 INCHES EVIDENT ON THE REGIONAL 12Z
RAOBS. BELIEVE THAT THE CONVECTION OVER SE TX SHOULD BECOME MORE
NUMEROUS THIS AFTERNOON AS IT INTERACTS WITH THE NEARLY STATIONARY
FRONT.
HAVE HAD TO MAKE QUITE A FEW CHANGES TO THE FORECAST FOR THE LATE
MORNING UPDATE...LOWERING POPS TO MID CHANCE ALONG THE I-20
CORRIDOR OF E TX/N LA...WHILE ALSO TAPERING POPS A BIT FARTHER N
BUT BELOW I-30 INTO EXTREME SRN AR. DID MAINTAIN LIKELY POPS TODAY
FOR THE NRN ZONES AS WELL AS DEEP E TX/SRN SECTIONS OF NCNTRL
LA...WITH ANY HEAVY RAIN THREAT BRIEF AND LOCALIZED. ALSO HAD TO
LOWER TEMPS CONSIDERABLY N OF THE STALLED FRONT...ESPECIALLY ALONG
THE I-20 CORRIDOR OF E TX/N LA. AREAS NEAR/S OF THE FRONT OVER
DEEP E TX/NCNTRL LA ARE ALREADY NEARING THEIR FORECAST MAX
TEMPS...BUT WITH CONVECTION EXPECTED TO AFFECT THESE AREAS BY
EARLY AFTERNOON...TEMPS SHOULD NOT WARM MUCH FURTHER BEFORE THE
CONVECTION SETS IN.
ZONE UPDATE ALREADY OUT...GRIDS WILL BE AVAILABLE SHORTLY.
15
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 81 66 80 65 86 / 40 30 20 10 10
MLU 81 68 80 63 83 / 40 50 20 10 10
DEQ 71 61 73 59 79 / 70 30 10 10 10
TXK 73 62 76 60 81 / 60 30 10 10 10
ELD 74 64 75 60 80 / 50 30 10 10 10
TYR 80 64 78 65 87 / 40 30 10 10 10
GGG 81 65 80 65 87 / 40 30 10 10 10
LFK 92 70 85 67 89 / 60 50 30 10 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1153 AM CDT FRI SEP 12 2014
.DISCUSSION...
A WEAK COLD FRONT REMAINS DRAPED FROM W TO E ACROSS THE REGION
THIS MORNING...AND SHOWS UP WELL VIA THE LOW STRATUS FIELD ON THE
VISIBLE SATELLITE IMAGERY. THE LEADING EDGE OF THIS BNDRY EXTENDS
FROM NEAR A ACT...TO PSN/JSO...TO RFI...THEN SE TO NEAR A IER TO
ESF LINE AS OF 16Z...WITH THE SHORT TERM PROGS HOLDING IT NEARLY
STATIONARY THROUGH THE AFTERNOON BEFORE SLOWLY MIXING IT S JUST
BEFORE SUNSET. MEANWHILE...SCT TO NUMEROUS AREAS OF SHRA WITH
EMBEDDED TSRA CONTINUE N OF THE FRONT ACROSS EXTREME NE TX/SW
AR/SE OK...WHERE 850MB THETA-E RIDGING HAS DEVELOPED JUST AHEAD OF
THE 850MB TROUGH OVER SE OK/SW AR. THIS RAINFALL IS BEING FURTHER
ENHANCED FROM ELEVATED MOISTURE FROM TS ODILE ALONG THE WRN MX
COAST...WHICH IS ROUNDING THE FLAT UPPER RIDGING OVER SE TX/GULF
COAST REGION. FORTUNATELY...RAINFALL RATES HAVE NOT BEEN
EXCESSIVELY HEAVY THIS MORNING BUT LOOKS TO PERSIST THROUGH AT
LEAST MID-AFTERNOON /PER THE 12Z PROGS AND LATEST HRRR RUNS/
BEFORE DIMINISHING. MEANWHILE...A WEAK SEABREEZE OVER SE TX/SW LA
IS BEING ENHANCED BY AN UPPER LOW OVER ERN OLD MX...WITH SCT
CONVECTION HAVING ALREADY DEVELOPED ALONG THE COAST. VISIBLE
SATELLITE IMAGE INDICATES THAT TOWERS HAVE DEVELOPED JUST AHEAD OF
THE FRONT OVER DEEP E TX/WCNTRL LA...WITH 2500-3000 J/KG OF SBCAPE
HAVING DEVELOPED. DEEP LAYER SHEAR REMAINS QUITE WEAK...THUS THE
CONVECTION SHOULD BE PULSY BUT STILL CAPABLE OF BRIEF DOWNPOURS
GIVEN THE PW/S IN EXCESS OF 2 INCHES EVIDENT ON THE REGIONAL 12Z
RAOBS. BELIEVE THAT THE CONVECTION OVER SE TX SHOULD BECOME MORE
NUMEROUS THIS AFTERNOON AS IT INTERACTS WITH THE NEARLY STATIONARY
FRONT.
HAVE HAD TO MAKE QUITE A FEW CHANGES TO THE FORECAST FOR THE LATE
MORNING UPDATE...LOWERING POPS TO MID CHANCE ALONG THE I-20
CORRIDOR OF E TX/N LA...WHILE ALSO TAPERING POPS A BIT FARTHER N
BUT BELOW I-30 INTO EXTREME SRN AR. DID MAINTAIN LIKELY POPS TODAY
FOR THE NRN ZONES AS WELL AS DEEP E TX/SRN SECTIONS OF NCNTRL
LA...WITH ANY HEAVY RAIN THREAT BRIEF AND LOCALIZED. ALSO HAD TO
LOWER TEMPS CONSIDERABLY N OF THE STALLED FRONT...ESPECIALLY ALONG
THE I-20 CORRIDOR OF E TX/N LA. AREAS NEAR/S OF THE FRONT OVER
DEEP E TX/NCNTRL LA ARE ALREADY NEARING THEIR FORECAST MAX
TEMPS...BUT WITH CONVECTION EXPECTED TO AFFECT THESE AREAS BY
EARLY AFTERNOON...TEMPS SHOULD NOT WARM MUCH FURTHER BEFORE THE
CONVECTION SETS IN.
ZONE UPDATE ALREADY OUT...GRIDS WILL BE AVAILABLE SHORTLY.
15
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 81 66 80 65 86 / 40 30 20 10 10
MLU 81 68 80 63 83 / 40 50 20 10 10
DEQ 71 61 73 59 79 / 70 30 10 10 10
TXK 73 62 76 60 81 / 60 30 10 10 10
ELD 74 64 75 60 80 / 50 30 10 10 10
TYR 80 64 78 65 87 / 40 30 10 10 10
GGG 81 65 80 65 87 / 40 30 10 10 10
LFK 92 70 85 67 89 / 60 50 30 10 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
15
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
609 PM EDT FRI SEP 12 2014
.SYNOPSIS...
COOL WEATHER WILL CARRY THROUGH MUCH OF THE NEXT SEVEN DAYS. LOW
PRESSURE PASSING SATURDAY BRINGS THE CHANCE FOR SHOWERS...OUTSIDE
EASTERN OHIO. AFTER A PERIOD OF DRY WEATHER THANKS TO HIGH
PRESSURE...THE NEXT COLD FRONT IS PREDICTED TO CROSS TUESDAY INTO
WEDNESDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
SKIES HAVE GENERALLY CLEARED IN THE RIDGES AND IN ALL POINTS TO
THEIR EAST. AS LOW LEVEL FLOW AS TURNED A BIT MORE EASTERLY...A
HINT OF DOWNSLOPE MAY ERODE THE EASTERN EDGE OF THE STRATUS SHIELD
PRIOR TO MID-CLOUD INCREASING. SKY GRIDS WERE ADJUSTED
ACCORDINGLY...HOWEVER ONLY THE EASTERN FRINGE OF THE FORECAST AREA
IS LIKELY TO BENEFIT FROM ANY SCATTERING OUT/CLEARING...WHILE THE
STRATUS SHOULD HOLD IN THE MAJORITY OF THE AREA UNTIL THE ARRIVAL
OF A DEEPER CLOUD SHIELD. FRIES
PREVIOUS DISCUSSION FOLLOWS AND IS STILL LARGELY
APPLICABLE...CLOUDY DAY ACROSS THE PBZ CWA. MDCRS PLOT FROM PIT
CONTINUES TO SHOW A STOUT INVERSION JUST ABOVE H900.
HOWEVER...CLOUDS ARE STARTING TO ERODE A BIT FROM THE EASTERN
RIDGES...GARRETT AND TUCKER COUNTIES IN PARTICULAR ARE GETTING
SOME SUN. WHILE THIS SLOW TREND SHOULD CONTINUE FOR A FEW HOURS
WITH LBE AND DUJ BENEFITING A BIT...I AM DUBIOUS THAT MUCH CLOUD
BREAKUP WILL OCCUR FROM PIT ON WEST. RAP SOUNDINGS CONCUR WITH
THIS. IN ANY EVENT...AREAS THAT CLEAR WILL START TO SEE MID CLOUDS
INCREASE THIS EVENING IN SW FLOW ALOFT AHEAD OF NEXT SYSTEM.
MODELS ARE IN GOOD AGREEMENT ON THE SCENARIO. FAIRLY SHARP H500
SHORWAVE WILL MOVE ACROSS THE GREAT LAKES TONIGHT AND INTO SOUTHERN
QUEBEC BY 00Z SUNDAY. A WEAK SURFACE WAVE WILL FORM ALONG THE FRONT
FROM YESTERDAY AND MOVES NORTHEAST THROUGH THE CAROLINAS TONIGHT.
IN OUR CWA...INVERTED TROUGHING AT THE SURFACE WILL HELP TO PULL
DEEPER MOISTURE BACK NORTHWARD...ESPECIALLY EAST OF THE OHIO RIVER.
PWATS RISE TO AROUND 1.5 INCHES FOR A SHORT TIME SOUTH OF PIT LATE
TONIGHT. POPS LITTLE CHANGED FROM PREVIOUS SHIFT...WITH LIKELY
VALUES EAST OF HLG/PIT/FKL AND LESSER TO THE WEST. LOOKING FOR A
QUARTER TO A HALF INCH OF RAIN AT MOST ALONG THE RIDGES. THUNDER
NOT EXPECTED.
SHORTWAVE TROUGH AXIS QUICKLY ROTATES THROUGH AFTER 12Z
SATURDAY...WHICH WILL SHUNT THE DEEP MOISTURE EASTWARD BY
MIDAFTERNOON. A FEW SHOWERS MAY LINGER IN LOW LEVEL NW FLOW...BUT
EXPECTING ALL RAIN TO WRAP UP BY 00Z SUNDAY...WHEN A SURFACE HIGH
BEGINS TO ARRIVE FROM THE WEST.
BELOW SEASONAL TEMPERATURES WILL CONTINUE.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
BLDG HIGH PRES WL BRING DRY WEA THRU ERLY MON. THE HIGH WL SHIFT E
MON AFTN...WITH INCRG CLDS AHD OF THE NXT APCHG SHRTWV. TEMPS WL
CONT TO AVG BLO SEASONAL LVLS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE ADVNG SHRTWV IS EXPD TO SPAWN SHWRS MONDAY NGT AND EARLY TUES.
SFC HIGH PRES...UNDR BROAD ERN CONUS TROFG...IS THEN FORECAST TO
MAINTAIN DRY...BUT SEASONABLY COOL WEATHER FOR THE RMNDR OF THE
LONG TERM PD. LONG TERM TEMPS WERE FORECAST USING HPC GUIDANCE...
TWEAKED UPWARD VIA GFS MOS TRENDS.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
MVFR CIGS ACROSS THE BOARD CONTINUE THIS AFTERNOON. INVERSION
ALOFT IS HANGING TOUGH BUT IS STARTING TO BREAK ALONG THE RIDGES
EAST OF LBE/DUJ. THINK SOME CLEARING...AND RETURN TO VFR
CONDITIONS...WILL REACH LBE/DUJ/MGW OVER THE NEXT FEW HOURS.
FORECAST BECOMES A BIT MORE PROBLEMATIC FURTHER WEST AS MODELS
SHOW INVERSION HANGING ON HERE. FOR NOW KEEPING A HIGH MVFR/LOW
VFR CIG AT PIT/AGC/HLG THIS EVENING AND WILL WATCH TRENDS. NEXT
SHORTWAVE/WEAK SURFACE WAVE APPROACHES LATER TONIGHT AND PASSES
THROUGH SATURDAY MORNING. MVFR CIG/VIS IN SHRA MAINLY FROM PIT ON
EAST. BORDERLINE MVFR/VFR CIGS WITH LESS CHANCE OF SHRA TO THE WEST.
OUTLOOK...THURSDAY NIGHT THROUGH TUESDAY...
NEXT FRONTAL SYSTEM WITH POSSIBLE RESTRICTIONS ARRIVES MONDAY
NIGHT INTO TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
244 PM EDT FRI SEP 12 2014
.SYNOPSIS...
COOL WEATHER WILL CARRY THROUGH MUCH OF THE NEXT SEVEN DAYS. LOW
PRESSURE PASSING SATURDAY BRINGS THE CHANCE FOR SHOWERS...OUTSIDE
EASTERN OHIO. AFTER A PERIOD OF DRY WEATHER THANKS TO HIGH
PRESSURE...THE NEXT COLD FRONT IS PREDICTED TO CROSS TUESDAY INTO
WEDNESDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
CLOUDY DAY ACROSS THE PBZ CWA. MDCRS PLOT FROM PIT CONTINUES TO
SHOW A STOUT INVERSION JUST ABOVE H900. HOWEVER...CLOUDS ARE
STARTING TO ERODE A BIT FROM THE EASTERN RIDGES...GARRETT AND TUCKER
COUNTIES IN PARTICULAR ARE GETTING SOME SUN. WHILE THIS SLOW TREND
SHOULD CONTINUE FOR A FEW HOURS WITH LBE AND DUJ BENEFITING A
BIT...I AM DUBIOUS THAT MUCH CLOUD BREAKUP WILL OCCUR FROM PIT ON
WEST. RAP SOUNDINGS CONCUR WITH THIS. IN ANY EVENT...AREAS THAT
CLEAR WILL START TO SEE MID CLOUDS INCREASE THIS EVENING IN SW FLOW
ALOFT AHEAD OF NEXT SYSTEM.
MODELS ARE IN GOOD AGREEMENT ON THE SCENARIO. FAIRLY SHARP H500
SHORWAVE WILL MOVE ACROSS THE GREAT LAKES TONIGHT AND INTO SOUTHERN
QUEBEC BY 00Z SUNDAY. A WEAK SURFACE WAVE WILL FORM ALONG THE FRONT
FROM YESTERDAY AND MOVES NORTHEAST THROUGH THE CAROLINAS TONIGHT.
IN OUR CWA...INVERTED TROUGHING AT THE SURFACE WILL HELP TO PULL
DEEPER MOISTURE BACK NORTHWARD...ESPECIALLY EAST OF THE OHIO RIVER.
PWATS RISE TO AROUND 1.5 INCHES FOR A SHORT TIME SOUTH OF PIT LATE
TONIGHT. POPS LITTLE CHANGED FROM PREVIOUS SHIFT...WITH LIKELY
VALUES EAST OF HLG/PIT/FKL AND LESSER TO THE WEST. LOOKING FOR A
QUARTER TO A HALF INCH OF RAIN AT MOST ALONG THE RIDGES. THUNDER
NOT EXPECTED.
SHORTWAVE TROUGH AXIS QUICKLY ROTATES THROUGH AFTER 12Z
SATURDAY...WHICH WILL SHUNT THE DEEP MOISTURE EASTWARD BY
MIDAFTERNOON. A FEW SHOWERS MAY LINGER IN LOW LEVEL NW FLOW...BUT
EXPECTING ALL RAIN TO WRAP UP BY 00Z SUNDAY...WHEN A SURFACE HIGH
BEGINS TO ARRIVE FROM THE WEST.
BELOW SEASONAL TEMPERATURES WILL CONTINUE.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
BLDG HIGH PRES WL BRING DRY WEA THRU ERLY MON. THE HIGH WL SHIFT E
MON AFTN...WITH INCRG CLDS AHD OF THE NXT APCHG SHRTWV. TEMPS WL
CONT TO AVG BLO SEASONAL LVLS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE ADVNG SHRTWV IS EXPD TO SPAWN SHWRS MONDAY NGT AND EARLY TUES.
SFC HIGH PRES...UNDR BROAD ERN CONUS TROFG...IS THEN FORECAST TO
MAINTAIN DRY...BUT SEASONABLY COOL WEATHER FOR THE RMNDR OF THE
LONG TERM PD. LONG TERM TEMPS WERE FORECAST USING HPC GUIDANCE...
TWEAKED UPWARD VIA GFS MOS TRENDS.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
MVFR CIGS ACROSS THE BOARD CONTINUE THIS AFTERNOON. INVERSION
ALOFT IS HANGING TOUGH BUT IS STARTING TO BREAK ALONG THE RIDGES
EAST OF LBE/DUJ. THINK SOME CLEARING...AND RETURN TO VFR
CONDITIONS...WILL REACH LBE/DUJ/MGW OVER THE NEXT FEW HOURS.
FORECAST BECOMES A BIT MORE PROBLEMATIC FURTHER WEST AS MODELS
SHOW INVERSION HANGING ON HERE. FOR NOW KEEPING A HIGH MVFR/LOW
VFR CIG AT PIT/AGC/HLG THIS EVENING AND WILL WATCH TRENDS. NEXT
SHORTWAVE/WEAK SURFACE WAVE APPROACHES LATER TONIGHT AND PASSES
THROUGH SATURDAY MORNING. MVFR CIG/VIS IN SHRA MAINLY FROM PIT ON
EAST. BORDERLINE MVFR/VFR CIGS WITH LESS CHANCE OF SHRA TO THE WEST.
OUTLOOK...THURSDAY NIGHT THROUGH TUESDAY...
NEXT FRONTAL SYSTEM WITH POSSIBLE RESTRICTIONS ARRIVES MONDAY
NIGHT INTO TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
715 PM EDT SAT SEP 13 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 409 PM EDT SAT SEP 13 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW THE VIGOROUS SHORTWAVE
THAT PRODUCED PCPN OVER MUCH OF UPPER MI LAST NIGHT NOW MOVING THRU
SRN ONTARIO INTO QUEBEC. UPSTREAM...A PAIR OF SHORTWAVES ARE
NOTED...ONE OVER ND/SRN MANITOBA AND THE OTHER OVER SRN
SASKATCHEWAN. THESE WAVES WILL BRING THE NEXT PCPN CHC TO UPPER MI
ON SUNDAY. IN THE WAKE OF LAST NIGHTS SYSTEM...850MB TEMPS ARE
CURRENTLY -1 TO -2C OVER LAKE SUPERIOR. TYPICALLY AT THIS TIME OF
YEAR...THIS WOULD BE MORE THAN SUFFICIENT FOR LAKE EFFECT CLOUDS AND
PCPN. HOWEVER...WITH A LARGE PORTION OF LAKE SUPERIOR HAVING SFC
WATER TEMPS PROBABLY ONLY AROUND 7-9C...THERE WAS NOT MUCH IN THE
WAY OF LAKE EFFECT CLOUDS EARLIER TODAY. IN FACT...THE LAKE HAS
BEHAVED MOSTLY AS STABILIZING INFLUENCE. ONE BAND WITH A FEW
SPRINKLES DID STREAM INTO ERN MARQUETTE COUNTY BRIEFLY THIS MORNING
DUE TO LAND BREEZE CONVERGENCE AND WARMER WATER TO THE S AND E OF
THE KEWEENAW. THIS AFTN...DAYTIME HEATING/LOW-LEVEL CONVERGENCE AND
MOISTURE FROM THE LAKE RESULTED IN ADDITIONAL SPRINKLES DEVELOPING
IN ERN MARQUETTE COUNTY. THESE SPRINKLES ARE DRIFTING SE THRU DELTA
AND WRN ALGER COUNTIES. WHILE LAKE EFFECT CLOUDS WERE AT A MINIMUM
EARLIER TODAY...850MB THERMAL TROF COMBINED WITH ADDED MOISTURE FROM
THE LAKE RESULTED IN WIDESPREAD CU/STRATOCU DEVELOPING OVER THE LAND
ONCE DAYTIME HEATING BEGAN.
TONIGHT...MAIN FCST CONCERN IS FROST POTENTIAL. WHILE CU/STRATOCU IS
STILL QUITE EXTENSIVE...THE DIURNAL NATURE OF THE CLOUD DEVELOPMENT
SUGGESTS THE CLOUDS WILL DISSIPATE THIS EVENING WITH THE LOSS OF
DAYTIME HEATING. MEANWHILE...LEAD SHORTWAVE TO THE W IS GENERATING A
FAIR AMOUNT OF HIGH CLOUDINESS WHICH WILL STREAM OVER THE FCST AREA
AS THE WAVE MOVES OVER THE UPPER LAKES. DISSIPATING STRATOCU THIS
EVENING BEING REPLACED BY HIGH CLOUDS WILL BE ONE FACTOR HELPING TO
KEEP TEMPS FROM CRASHING. OTHER FACTOR WILL BE DEPARTURE OF HIGH
PRES RIDGE CURRENTLY OVER THE AREA. AS PRES GRADIENT TIGHTENS BTWN
THE EXITING HIGH AND APPROACHING SFC TROF... THERE WILL BE SOME
INCREASE IN MIXING. THAT SAID...THE INITIAL DRY AIR MASS
(PRECIPITABLE WATER 45-55PCT OF NORMAL) AND LIGHT WINDS OVER THE
AREA WILL STILL ALLOW TEMPS TO FALL INTO THE MID 30S AND TO EVEN THE
LOWER 30S IN TRADITIONAL COLD SPOTS. SO...FCST WILL SHOW PATCHY
FROST OVER MUCH OF THE INTERIOR. AT THIS POINT...NOT EXPECTING
COVERAGE TO BE LARGE ENOUGH TO WARRANT A FROST ADVY. EVENING SHIFT
WILL NEED TO MONITOR CLOUD TRENDS AND TEMPS TO RE-EXAMINE THE NEED
FOR HEADLINE ISSUANCE BY LATE EVENING.
ON SUN...SECOND SHORTWAVE WILL SWING ACROSS THE UPPER GREAT LAKES.
AS IN PREVIOUS DAYS...MODELS CONTINUE TO INDICATE BEST
MOISTURE/FORCING PASSING JUST N OF THE AREA...ALONG AND N OF
PROJECTED VORT TRACK. SEE NO REASON TO DEVIATE MUCH FROM PREVIOUS
FCST WITH MAINLY CHC POPS SPREADING INTO WRN UPPER MI IN THE MID TO
LATE MORNING AND THEN REACHING THE E MID TO LATE AFTN. EXPECT HIGH
TEMPS GENERALLY IN THE UPPER 50S TO LWR 60S.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 350 PM EDT SAT SEP 13 2014
SPLIT FLOW PATTERN ALOFT TO START THE LONG TERM PERIOD BUT NORTHERN
BRANCH IS BY FAR STRONGER AND MORE INFLUENTIAL ON THE WEATHER OVER
MUCH OF NORTH AMERICA. TROUGHING CENTERED OVER NUNAVUT CANADA TO THE
NORTH OF HUDSON BAY WILL KEEP A TROUGH/BELOW NORMAL TEMPS OVER MOST
OF CANADA AND INTO THE GREAT LAKES AND REST OF THE EASTERN CONUS
THIS WEEK. RIDGING OVER THE WESTERN CONUS AND WESTERN CANADA SHOULD
SLOWLY SLIDE EAST BY THE END OF THE WEEK AS DEEP TROUGH CURRENTLY
OVER ALASKA RE-ORIENTS OVER THE GULF OF ALASKA WHILE SLIGHTLY
OPENING UP. MAY SEE A WARM UP LATE THIS WEEK AND BEYOND AS
RIDGING...OR AT LEAST LESS TROUGHING...AFFECTS THE PLAINS AND GREAT
LAKES. PATTERN DOES NOT LOOK TO PROVIDE MUCH IN WAY OF RAIN THE NEXT
WEEK. PRIMARY CHANCES WOULD BE WITH COLD FRONT MOVING THROUGH ON
TUESDAY NIGHT AND AGAIN BY NEXT WEEKEND AS WARM AIR ADVECTION STARTS
TO SPREAD IN FROM THE WEST.
SUNDAY NIGHT INTO MONDAY...SHORTWAVE AND ASSOCIATED COLD FRONT MOVES
OUT OF EASTERN CWA AFTER MIDNIGHT ON SUNDAY NIGHT. WILL LINGER SLIGHT
CHANCE POPS OVER THE EAST AFTER MIDNIGHT. THERMAL TROUGH WITH LOWER
H7 TEMPS AND A POCKET OF H85-H7 RH ALONG WITH DAYTIME HEATING MAY
RESULT IN ISOLD SHRA VCNTY OF LAKE BREEZES OVER EASTERN CWA ON
MONDAY AFTN. DRYING AND SUBSIDENCE IN WAKE OF THE SUNDAY NIGHT
SHORTWAVE SHOULD LIMIT COVERAGE AND WILL ONLY KEEP SLIGHT CHANCES.
LI/S ARE A BIT BLO 0C BUT THINK THAT WITH FROPA WITHIN PREVIOUS 12
HR...THERE WILL ONLY BE ENOUGH INSTABILITY FOR SHRA SO DID NOT
MENTION ANY THUNDER.
SFC RIDGE SETTLES FROM THE NORTHERN PLAINS TO THE OHIO VALLEY BY
TUESDAY MORNING. COULD BE HIGH CLOUDS ON MONDAY NIGHT...BUT PWATS
ARE BLO 50 PCT OF NORMAL SO IT COULD BE CHILLY NIGHT WITH SOME FROST
POSSIBLE. WINDS LIGHT NEAR THE RIDGE AND THERE IS LIMITED ONSHORE
COMPONENT ANYWHERE IN CWA...SEEMS THAT ALL INTERIOR WOULD BE AT RISK
FOR THE COLD TEMPS/FROST. TUESDAY SHOULD BE DRY AS UPPER LAKES IS
BTWN THE RIDGE AND AN APPROACHING COLD FRONT. WSW WINDS AHEAD OF
FRONT AND H85 TEMPS UP TO 4-6C SHOULD RESULT IN TEMPS INTO THE 60S
WHICH IS AT LEAST CLOSER TO NORMAL. FRONT DROPS NORTH TO SOUTH OVER
THE AREA ON TUESDAY NIGHT OR WEDNESDAY MORNING. A BRIEF INTERLUDE OF
INCREASING H8-H6 MOISTURE AND WEAK LIFT JUST IN WAKE OF THE FRONT
MAY BE ENOUGH TO KICK OFF SOME SHOWERS TUESDAY NIGHT. COVERAGE OF
ANY SHOWERS WILL BE HELD BACK AS STRONGER FORCING FOR LIFT REMAINS
OVER NORTHERN ONTARIO CLOSER TO TRACK OF UPPER LEVEL JET DIGGING
INTO THE PERSISTENT TROUGH. INTO WEDNESDAY...COULD BE A LOT OF LOW
CLOUDS LINGERING BENEATH SUBSIDENCE ALOFT AS SUB H85 IT REMAINS COOL
AND MOIST WITH EASTERLY FLOW. ADDITIONAL MID CLOUDS MAY STREAM ACROSS
IN THE AFTN AS WELL. TEMPS WILL BE MUCH COOLER THAN THE DAY BEFORE
AND IT WILL ESPECIALLY FEEL THAT WAY WITH THE CLOUDS AND EAST WIND.
TEMPS IN THE LOW 50S NEAR LK SUPERIOR AND NEAR 60 OVER THE SCNTRL.
AS TROUGH ALOFT OVER EASTERN CANADA AND THE NORTHEAST CONUS SLOWLY
MOVES EAST AND RIDGE OVER WESTERN CONUS ALSO MOVES EAST...CONFLUENT
FLOW RESULTS IN SFC RIDGE MOVING FROM CNTRL CANADA ACROSS THE GREAT
LAKES AND EVENTUALLY TO THE EASTERN SEABOARD BY SATURDAY. DRY WEATHER
SHOULD HOLD OVER UPPER LAKES THROUGH THU NIGHT...WITH CHANCES
FOR RAIN INCREASING BY NEXT WEEKEND AS SHORTWAVE TROUGH MOVES TO THE
CNTRL PLAINS AND SFC FRONT SLIDES EASTWARD. LATEST GFS WHICH HAD
BEEN VERY AGRESSIVE IN PREVIOUS MODEL RUNS BRINGING QPF TO THE
UPPER GREAT LAKES BY FRIDAY NOW LOOKS SIMILAR TO THE SLOWER 00Z
ECMWF. ON THE FLIP SIDE...THE LATEST ECMWF IS MUCH MORE BULLISH
BRINGING QPF ACROSS ALL OF UPR MICHIGAN BY FRIDAY AFTN AS WHERE IT
HAD BEEN INSISTENT ON A RIDGE...IT HAS A STRONGER SHORTWAVE TROUGH.
MODEL CONSISTENCY IS LACKING AND WILL GO WITH A CONSENSUS OF ALL THE
MODELS WITH LOW CHANCES FOR SHRA/TSRA BEGINNING ON FRIDAY AND
LASTING INTO NEXT WEEKEND. GENERALLY...TEMPS WILL RUN BELOW NORMAL
THE UPCOMING WEEK...THOUGH IT DOES APPEAR THAT IN ADDITION TO THE
WARMER TEMPS ON TUESDAY AHEAD OF A COLD FRONT...READINGS ON FRIDAY
AND SATURDAY MAY TRY TO PUSH TO AROUND NORMAL. WILL ALL DEPEND ON
EXTENT OF CLOUDS AND SHRA/TSRA. COUPLE OF CHILLY NIGHTS POSSIBLE
WEDNESDAY NIGHT AND THURSDAY NIGHT AS THE HIGH IS IN THE VCNTY AND
PWATS ARE WELL BLO 50 PCT OF NORMAL. IF SKIES ARE MAINLY CLEAR
EITHER NIGHT...TEMPS COULD BE AROUND FREEZING AND THERE WOULD BE
FROST. ATTM...BEST CHANCE FOR IDEAL RADIATIONAL COOLING CONDITIONS
WOULD BE ON WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 715 PM EDT SAT SEP 13 2014
UNDER RELATIVELY DRY LOW LEVELS...VFR CONDITIONS WILL PREVAIL THRU
THE FCST PERIOD AT KIWD/KCMX/KSAW. ON SUN...AN APPROACHING LOW PRES
TROF SHOULD BRING SCT -SHRA INTO NW UPPER MI BY AFTN. HAVE INCLUDED
A VCSH MENTION AT KCMX.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 409 PM EDT SAT SEP 13 2014
APPROACHING LOW PRES TROF WILL RESULT IN INCREASING S TO SW WINDS
TONIGHT INTO SUN. WHILE LOWER OBS PLATFORMS SHOULDN`T SEE WINDS
GREATER THAN THE 10-20KT RANGE...HIGH OBS PLATFORMS WILL PROBABLY
SEE GUSTS TO AROUND 25KT. WINDS SHOULD FALL BACK TO MOSTLY 10-20KT
SUN NIGHT THRU MON. THERE MAY BE SOMEWHAT HIGHER WINDS AGAIN LATE
MON NIGHT THRU EARLY WED AHEAD OF AND BEHIND A COLD FRONT THAT WILL
DROP S ACROSS LAKE SUPERIOR TUE. LIGHTER WINDS WILL THEN BE THE RULE
LATER WED THRU THU HAS HIGH PRES MOVE SE ACROSS NRN ONTARIO TOWARD
THE LOWER LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...07
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
146 PM EDT FRI SEP 12 2014
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 12 2014
COOL WEATHER WILL CONTINUE INTO THE WEEKEND. WEAK LOW PRESSURE
WILL BRING SOME SHOWERS LATE TODAY THROUGH TONIGHT. THE HIGH
PRESSURE BUILDS IN FOR SATURDAY AND SUNDAY. SOME FROST IS EXPECTED
NORTH OF GRAND RAPIDS SATURDAY NIGHT.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY EVENING)
ISSUED AT 1121 AM EDT FRI SEP 12 2014
LITTLE QUESTION THERE WILL BE RAIN ACROSS THE CWA TONIGHT THANKS A
CLOSING OFF UPPER LOW. THE BEST DYNAMICS ARE OVER CENTRAL AND
NORTHERN LOWER MICHIGAN... SO THAT IS WHERE IT BELIEVE THE HEAVIEST
RAIN WILL BE. NEARLY ALL OF OUR CWA WILL GET RAIN FROM THIS
SYSTEM. BASED ON THE LATEST HRRR AND LOOKING AT CONDENSATION
PRESSURE DEFICITS FROM THE NAM 12Z RUN... IT WOULD SEEM THE RAIN
MAY START AS EARLY AS 3-4 PM NEAR ROUTE 10 BUT NOT REACH I-96 TILL
NEAR US-131 BY 8-9 PM. I UPDATED THE GRIDS TO REFLECT THIS TIMING.
AS A SIDE NOTE SEEMS WE WILL GET A NORTH TO SOUTH MID LAKE
ENHANCED PRECIPITATION BAND BUT THAT SHOULD STAY OFF SHORE THROUGH
THE NIGHT DUE TO THE NORTH WINDS DURING THE EVENT TONIGHT. HOWEVER
THE BAND MAY TOUCH PARTS OF EXTREME WESTERN MASON COUNTY TOWARD
MORNING. IF IT DOES EXPECT A PERIOD OF HEAVIER RAIN SHOWERS.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 324 AM EDT FRI SEP 12 2014
THE FOCUS OF THE LONG TERM IS CENTERED ON THE MON/MON NIGHT TIME
FRAME WHEN OUR BEST CHC FOR PCPN WILL BE.
THE DRY WEATHER FOR THE LATTER HALF OF THE UPCOMING WEEKEND WILL
GRADUALLY COME TO AN END LATE SUN NIGHT AND MON ACROSS THE AREA. WE
WILL SEE A COLD FRONT DROP INTO THE AREA AT THAT TIME AS A LONG WAVE
TROUGH ACROSS CENTRAL AND EASTERN CANADA SLIPS SOUTH INTO THE AREA.
PCPN ALONG THE FRONT IS INITIALLY A BIT SPARSE...HOWEVER THIS LOOKS
TO CHANGE AS A STRONG SHORT WAVE ROUNDING THE BASE OF THE LONG WAVE
TROUGH WILL INTERACT WITH THE FRONT ON MON AND MON EVENING.
RAIN WILL COME TO AN END ACROSS THE ENTIRE AREA BY 12Z TUE AS THE
SHORT WAVE TROUGH AXIS MOVES EAST OF THE CWFA. DRY WEATHER IS THEN
LIKELY TO HOLD FOR THE REMAINDER OF THE WEEK. WE WILL SEE A COOL NW
FLOW HOLD IN ACROSS THE AREA FOR THE REMAINDER OF THE WEEK. THE GOOD
THING IS THAT WE WILL BE IMMEDIATELY DOWNSTREAM FROM THE LONG WAVE
UPPER RIDGE AXIS ACROSS THE ROCKIES. THE SUBSIDENCE DOWNSTREAM FROM
THE RIDGE WILL KEEP THE WEATHER QUIET AND COOL. THE RIDGE GETS
FLATTENED A BIT BY THE END OF THE PERIOD AS ENERGY DIVING SOUTH FROM
CANADA TRIES TO MOVE IN. THE UPPER JET WILL REMAIN NORTH OF THE AREA
AND WILL HOLD A COLD FRONT ACROSS LAKE SUPERIOR UP THERE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 146 PM EDT FRI SEP 12 2014
AS MENTIONED IN THE PREVIOUS DISCUSSION...EXPECT MVFR CIGS TO
SPREAD SOUTHEAST THIS AFTERNOON AND TONIGHT WITH AN AREA OF MOSTLY
LIGHT RAIN. ALTHOUGH NOT ADVERTISED AT ALL OF THE TERMINALS...
CEILINGS COULD DROP BELOW THE FUEL ALTERNATE THRESHOLD OF 2000 FT
AGL. IFR CEILINGS ARE ALSO NOT OUT OF THE QUESTION AT MKG AFTER
06Z. OVERALL...THERE ARE FEWER CONCERNS ABOUT RESTRICTIONS TO
VISIBILITY.
&&
.MARINE...
ISSUED AT 1121 AM EDT FRI SEP 12 2014
I ADDED WATER SPOUTS TO THE NEAR SHORE FORECAST FROM LATE
AFTERNOON INTO MID MORNING SATURDAY BASED ON THE CONVECTIVE DEPTH
BEING BETWEEN 10000 FT AND 15000 FT AT MID LAKE... USING LAKE
TEMP TO 850 TEMP DIFFERENCES BETWEEN 15C AND 18C. WINDS WILL NOT BE
STRONG ENOUGH FOR SCA. IN SUPPORT OF THAT...BEACH CAMS AT 11 AM SHOW
LITTLE IN THE WAY OF SIGNIFICANT WAVE ACTION. THE PORT SHELDON HAS
SHOWN 1 TO 1.3 FOOT WAVES OVER THE PAST SEVERAL HOURS.
&&
.HYDROLOGY...
ISSUED AT 324 AM EDT FRI SEP 12 2014
NO HYDRO ISSUES EXPECTED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...OSTUNO
SHORT TERM...WDM
LONG TERM...NJJ
AVIATION...TJT
HYDROLOGY...OSTUNO
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1121 AM EDT FRI SEP 12 2014
LATEST UPDATE...
SHORT TERM/MARINE
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 12 2014
COOL WEATHER WILL CONTINUE INTO THE WEEKEND. WEAK LOW PRESSURE
WILL BRING SOME SHOWERS LATE TODAY THROUGH TONIGHT. THE HIGH
PRESSURE BUILDS IN FOR SATURDAY AND SUNDAY. SOME FROST IS EXPECTED
NORTH OF GRAND RAPIDS SATURDAY NIGHT.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY EVENING)
ISSUED AT 1121 AM EDT FRI SEP 12 2014
LITTLE QUESTION THERE WILL BE RAIN ACROSS THE CWA TONIGHT THANKS A
CLOSING OFF UPPER LOW. THE BEST DYNAMICS ARE OVER CENTRAL AND
NORTHERN LOWER MICHIGAN... SO THAT IS WHERE IT BELIEVE THE HEAVIEST
RAIN WILL BE. NEARLY ALL OF OUR CWA WILL GET RAIN FROM THIS
SYSTEM. BASED ON THE LATEST HRRR AND LOOKING AT CONDENSATION
PRESSURE DEFICITS FROM THE NAM 12Z RUN... IT WOULD SEEM THE RAIN
MAY START AS EARLY AS 3-4 PM NEAR ROUTE 10 BUT NOT REACH I-96 TILL
NEAR US-131 BY 8-9 PM. I UPDATED THE GRIDS TO REFLECT THIS TIMING.
AS A SIDE NOTE SEEMS WE WILL GET A NORTH TO SOUTH MID LAKE
ENHANCED PRECIPITATION BAND BUT THAT SHOULD STAY OFF SHORE THROUGH
THE NIGHT DUE TO THE NORTH WINDS DURING THE EVENT TONIGHT. HOWEVER
THE BAND MAY TOUCH PARTS OF EXTREME WESTERN MASON COUNTY TOWARD
MORNING. IF IT DOES EXPECT A PERIOD OF HEAVIER RAIN SHOWERS.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 324 AM EDT FRI SEP 12 2014
THE FOCUS OF THE LONG TERM IS CENTERED ON THE MON/MON NIGHT TIME
FRAME WHEN OUR BEST CHC FOR PCPN WILL BE.
THE DRY WEATHER FOR THE LATTER HALF OF THE UPCOMING WEEKEND WILL
GRADUALLY COME TO AN END LATE SUN NIGHT AND MON ACROSS THE AREA. WE
WILL SEE A COLD FRONT DROP INTO THE AREA AT THAT TIME AS A LONG WAVE
TROUGH ACROSS CENTRAL AND EASTERN CANADA SLIPS SOUTH INTO THE AREA.
PCPN ALONG THE FRONT IS INITIALLY A BIT SPARSE...HOWEVER THIS LOOKS
TO CHANGE AS A STRONG SHORT WAVE ROUNDING THE BASE OF THE LONG WAVE
TROUGH WILL INTERACT WITH THE FRONT ON MON AND MON EVENING.
RAIN WILL COME TO AN END ACROSS THE ENTIRE AREA BY 12Z TUE AS THE
SHORT WAVE TROUGH AXIS MOVES EAST OF THE CWFA. DRY WEATHER IS THEN
LIKELY TO HOLD FOR THE REMAINDER OF THE WEEK. WE WILL SEE A COOL NW
FLOW HOLD IN ACROSS THE AREA FOR THE REMAINDER OF THE WEEK. THE GOOD
THING IS THAT WE WILL BE IMMEDIATELY DOWNSTREAM FROM THE LONG WAVE
UPPER RIDGE AXIS ACROSS THE ROCKIES. THE SUBSIDENCE DOWNSTREAM FROM
THE RIDGE WILL KEEP THE WEATHER QUIET AND COOL. THE RIDGE GETS
FLATTENED A BIT BY THE END OF THE PERIOD AS ENERGY DIVING SOUTH FROM
CANADA TRIES TO MOVE IN. THE UPPER JET WILL REMAIN NORTH OF THE AREA
AND WILL HOLD A COLD FRONT ACROSS LAKE SUPERIOR UP THERE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 732 AM EDT FRI SEP 12 2014
SOME IFR CEILINGS THIS MORNING AT AZO AND BTL BUT LOW STRATUS
SHOULD START TO LIFT TO MVFR THEN VFR BY THIS AFTERNOON. RAIN
SHOWERS WILL ARRIVE THIS EVENING WITH WIDESPREAD MVFR CONDITIONS
EXPECTED OVERNIGHT.
&&
.MARINE...
ISSUED AT 1121 AM EDT FRI SEP 12 2014
I ADDED WATER SPOUTS TO THE NEAR SHORE FORECAST FROM LATE
AFTERNOON INTO MID MORNING SATURDAY BASED ON THE CONVECTIVE DEPTH
BEING BETWEEN 10000 FT AND 15000 FT AT MID LAKE... USING LAKE
TEMP TO 850 TEMP DIFFERENCES BETWEEN 15C AND 18C. WINDS WILL NOT BE
STRONG ENOUGH FOR SCA. IN SUPPORT OF THAT...BEACH CAMS AT 11 AM SHOW
LITTLE IN THE WAY OF SIGNIFICANT WAVE ACTION. THE PORT SHELDON HAS
SHOWN 1 TO 1.3 FOOT WAVES OVER THE PAST SEVERAL HOURS.
&&
.HYDROLOGY...
ISSUED AT 324 AM EDT FRI SEP 12 2014
NO HYDRO ISSUES EXPECTED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...OSTUNO
SHORT TERM...WDM
LONG TERM...NJJ
AVIATION...OSTUNO
HYDROLOGY...OSTUNO
MARINE...WDM
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
541 PM CDT Fri Sep 12 2014
.SHORT TERM: (Through Tonight)
Issued at 236 PM CDT Fri Sep 12 2014
Cloud cover continues to cover the area this afternoon as stratus is
trapped under a low level inversion and mid-high level clouds are
streaming in ahead of a mid level trough. There has been some light
rain associated with the mid-level trough moving across northern
Missouri early this afternoon, but it`s coverage has been limited.
Latest runs of the RAP and HRRR still show some redevelopment of
some light rain over western Missouri this afternoon and this
evening ahead of the upper trough that will move across the CWA this
evening. Then expect clearing of the clouds from north to south
after 06Z as the upper trough moves to the east allowing subsidence
to set in. Drier air will move into the low levels as the inversion
weakens which should allow the low level clouds to move out.
Temperatures should fall close to agreeable MOS guidance for lows
once skies begin to clear with the light northeasterly winds.
Britt
.LONG TERM: (Saturday through Next Friday)
Issued at 236 PM CDT Fri Sep 12 2014
(Saturday through Monday)
Overall, mdls are in good agreement thru this period. Period begins
with a large sfc ridge settling across the region. This ridge will
keep temps around 15 degrees below seasonal average despite ample
insolation. As the ridge retreats, the approaching trof and sfc fnt
will bring another chance for precip to the region late in the
period. Some minor differences in timing are apparent among the mdl
guidance. Will keep PoPs lower except where mdls are in agreement.
(Tuesday through Friday)
Not much change from the prev forecast. Mdls remain in good
agreement overall thru the period with respect to mass fields
anyway. Sfc ridge builds into the region on Tues with precip coming
to an end Mon night. Cool temps will prevail thru mid week, tho not
as cool as this weekend. Mdls differ regarding precip chances for
late Wed into Thurs. The ECMWF is more robust with nocturnal
convection developing along a stationary fnt across the region. The
GFS would suggest height rising with the sfc ridge still holding on
into the area. Have kept PoPs low given the uncertainty forecasting
mesoscale features on day 7.
As for temps, have trended twd the warmer guidance thru the period
given heights over the region.
Tilly
&&
.AVIATION: (For the 00z TAFs through 00z Saturday Evening)
Issued at 534 PM CDT Fri Sep 12 2014
An extensive area of MVFR stratus/stratocumulus was in place
across the region at TAF issuance. Although drier air will be
working into the region overnight, there is still a lot of
moisture trapped below an inversion. This suggests that clouds
will be slow to clear even with the drier air. On the other hand,
recent satellite imagery has shown that upstream stratocu was
breaking up over IA/NE, and it is possible that cigs may clear
earlier than expected. Ceilings could fall to IFR at times
overnight until the drier air arrives. Intermittent light drizzle
or light rain may also occur over the next several hours.
Initially northerly winds will back slightly overnight then veer
tomorrow.
Specifics for KSTL: It is likely that MVFR ceilings will persist
overnight. Ceilings should rise by tomorrow morning at the latest
due to diurnal mixing and drier low-level air. Initially northerly
winds will back slightly overnight then veer tomorrow and become
easterly towards the end of the valid TAF period.
Kanofsky
&&
.CLIMATE:
Issued at 236 PM CDT Fri Sep 12 2014
Record Lows This Weekend:
STL COU UIN
13 43(1975) 33(1902) 33(1902)
14 46(1996) 40(1892) 38(1996)
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
239 PM CDT Fri Sep 12 2014
.SHORT TERM: (Through Tonight)
Issued at 236 PM CDT Fri Sep 12 2014
Cloud cover continues to cover the area this afternoon as stratus is
trapped under a low level inversion and mid-high level clouds are
streaming in ahead of a mid level trough. There has been some light
rain associated with the mid-level trough moving across northern
Missouri early this afternoon, but it`s coverage has been limited.
Latest runs of the RAP and HRRR still show some redevelopment of
some light rain over western Missouri this afternoon and this
evening ahead of the upper trough that will move across the CWA this
evening. Then expect clearing of the clouds from north to south
after 06Z as the upper trough moves to the east allowing subsidence
to set in. Drier air will move into the low levels as the inversion
weakens which should allow the low level clouds to move out.
Temperatures should fall close to agreeable MOS guidance for lows
once skies begin to clear with the light northeasterly winds.
Britt
.LONG TERM: (Saturday through Next Friday)
Issued at 236 PM CDT Fri Sep 12 2014
(Saturday through Monday)
Overall, mdls are in good agreement thru this period. Period begins
with a large sfc ridge settling across the region. This ridge will
keep temps around 15 degrees below seasonal average despite ample
insolation. As the ridge retreats, the approaching trof and sfc fnt
will bring another chance for precip to the region late in the
period. Some minor differences in timing are apparent among the mdl
guidance. Will keep PoPs lower except where mdls are in agreement.
(Tuesday through Friday)
Not much change from the prev forecast. Mdls remain in good
agreement overall thru the period with respect to mass fields
anyway. Sfc ridge builds into the region on Tues with precip coming
to an end Mon night. Cool temps will prevail thru mid week, tho not
as cool as this weekend. Mdls differ regarding precip chances for
late Wed into Thurs. The ECMWF is more robust with nocturnal
convection developing along a stationary fnt across the region. The
GFS would suggest height rising with the sfc ridge still holding on
into the area. Have kept PoPs low given the uncertainty forecasting
mesoscale features on day 7.
As for temps, have trended twd the warmer guidance thru the period
given heights over the region.
Tilly
&&
.AVIATION: (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 133 PM CDT Fri Sep 12 2014
Ceilings are expected to gradually increase above 2000 ft this
evening. Some light rain is expected to move across the area into
this evening, with most of this rain moving across northern
Missouri into central Illinois. The most likely TAF to be affected
by light rain will be Quincy. Then drier air moving into the area
overnight which will cause ceilings to climb above 3000 feet from
north to south. Dry and VFR conditions are then expected at the
terminals after 09Z.
Specifics for KSTL: Ceilings are expected to climb above 2000 ft
this afternoon and then become VFR tonight. There is some chance
for light rain between 00-06Z, but confidence is not high enough
to include in the TAF at this time. Dry and VFR conditions are
expected after 09Z.
Britt
&&
.CLIMATE:
Issued at 236 PM CDT Fri Sep 12 2014
Record Lows This Weekend:
STL COU UIN
13 43(1975) 33(1902) 33(1902)
14 46(1996) 40(1892) 38(1996)
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 47 66 48 72 / 20 0 0 0
Quincy 40 63 43 69 / 30 0 0 0
Columbia 41 65 43 72 / 30 0 0 5
Jefferson City 43 66 43 73 / 30 0 0 5
Salem 46 66 45 71 / 20 0 0 0
Farmington 44 66 40 72 / 20 0 0 0
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1121 PM CDT Thu Sep 11 2014
.UPDATE:
Issued at 950 PM CDT Thu Sep 11 2014
Grids have been updated to add patchy drizzle late tonight and
tomorrow morning.
Kanofsky
&&
.SHORT TERM: (Through Late Tonight)
Issued at 252 PM CDT Thu Sep 11 2014
Clouds have not cleared out this afternoon even though high
pressure has begun to build into the low levels. This is because
of persistent low level inversion that the RAP is showing around
900mb. Moisture is being trapped below this inversion, so expect
these clouds to persist into the night. Drizzle may redevelop over
the area toward morning. Temperatures did not climb much today and
do not have far to fall tonight to reach agreeable MOS guidance
for lows.
Britt
.LONG TERM: (Friday through Next Thursday)
Issued at 252 PM CDT Thu Sep 11 2014
Next shortwave to continue sliding southeast into forecast area on
Friday. Models in good agreement on timing and precipitation
associated with it. Will see isolated/widely scattered showers
develop and spread southeast across forecast area during the day
on Friday exiting late Friday evening. QPF amounts will be rather
light with best chances along and north of I-70. As for
temperatures, to remain well below normal with highs only in the
upper 50s to upper 60s. Lows Friday night will be in the low 40s
to low 50s.
Then on Saturday, strong ridge of high pressure to build in and
skies to clear out. Despite the sunshine, it will continue to feel
like fall with high temperatures only in the 60s and lows Saturday
night in the 40s.
By Sunday, surface ridge begins to move off to the east allowing
temperatures to slowly moderate. Highs will be in the upper 60s to
low 70s. Then Sunday night the next weather system to approach the
region with showers developing and spread southeast through region
Sunday night through Monday night. Frontal boundary to stall out
just south of forecast area early Tuesday morning with weak surface
ridging building in. Could see some lingering isolated/scattered
showers through Wednesday night for western and southern portions of
the area. As for temperatures, highs will be in the 70s and lows in
the 50s through next Thursday.
Byrd
&&
.AVIATION: (For the 06z TAFs through 06z Friday Night)
Issued at 1110 PM CDT Thu Sep 11 2014
Stratus remains widespread late this evening producing MVFR flight
conditions at all the terminals. There is however some drier air
slowly advecting southwestward due to northeasterly low level
winds. This has brought a jagged clearing line into far northern
MO which then curves back into far northern IL. There is potential
that KUIN could clear out for a time only to have clouds move back
in - confidence is low on the trends. I have also added a prob30
for light rain in the afternoon as an upper trof digs across the
upper MS valley. Elsewhere the aforementioned dry air has lessened
my confidence in the previously anticipated lower cigs overnight
and threat of drizzle. I have maintained it in the new TAFS
although with higher cigs and only a TEMPO group. Clearing should
commence at all sites Friday night, some of which is beyond the
valid forecast period.
Specifics for KSTL:
Stratus remains widespread late this evening producing MVFR flight
conditions. There is however some drier air slowly advecting
southwestward due to northeasterly low level winds. This could
could initially result in the cig height bouncing from 1800-2000
ft. The dry air has also lessened my confidence in the previously
anticipated lower cigs overnight and threat of drizzle. I have
maintained it in the new TAFS although with higher cigs and only a
TEMPO group. Otherwise MVFR flight conditions will persist on
Friday with with clearing late on Friday night.
Glass
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1246 PM CDT FRI SEP 12 2014
.SYNOPSIS...
ISSUED AT 337 AM CDT FRI SEP 12 2014
STRONG HIGH HOLDS OVER THE SOUTHERN CONUS. MAINLY ZONAL FLOW FROM
THE MISSOURI VALLEY THROUGH THE EAST COAST. PROGRESSIVE TROUGH OVER
THE NORTHERN PLAINS AND WEAK RIDGING INTO THE PACIFIC NORTHWEST.
&&
.UPDATE...
ISSUED AT 1021 AM CDT FRI SEP 12 2014
MORNING TEMPS ON THE RISE SO ALLOWED FROST/FREEZE HEADLINE TO
EXPIRE ACROSS THE NORTHWEST. NO CHANGE TO THE FROST HEADLINE FOR
THE SOUTHEAST CWA TONIGHT. COLD AIR ALOFT SHOULD COMBINE WITH
WARMING TEMPS ACROSS N CENTRAL...AS SKIES ARE CLEARING THERE TO
PRODUCE STEEP AFTERNOON LAPSE RATES. CLOUDS SHOULD QUICKLY FORM
AND EVEN COULD SEEM SOME SPRINKLES OR LIGHT RAIN SHOWERS. NAM AND
THE HRRR SUPPORT THE LIGHT RAIN SHOWERS PRODUCING SOME POCKETS OF
QPF.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT FRI SEP 12 2014
MODELS IN GOOD AGREEMENT AND WILL USE BLEND FOR THE FORECAST. MAIN
FORECAST CONCERN WILL BE ENDING OF PRECIPITATION AND PTYPE WITH
HIGHLIGHTS FOR FROST IN THE NORTHWEST THIS MORNING AND THEN FROST IN
THE FORECAST EARLY SATURDAY MORNING.
PRECIPITATION SOUTH OF A LINE FROM AINSWORTH TO OSHKOSH THIS MORNING.
MOST AREAS REPORTING RAIN THIS MORNING BUT SOME AREAS OF DRIZZLE AND
SIDNEY REPORTING SNOW WITH TEMPERATURES RIGHT AROUND FREEZING.
CEILINGS LIFTING TO THE NORTH AND SOME CLEARING OVER NORTHWEST SOUTH
DAKOTA. CLEARING LINE IS MOVING TO THE SOUTHEAST AROUND 20 KTS AND
SHOULD BE THROUGH KVTN MID MORNING. 1037MB SURFACE HIGH CENTERED
OVER KCDR THIS MORNING WITH 850MB TEMPERATURES AROUND -1C.
TEMPERATURES OVER NORTHWEST IN THE MID 30S WITH LIGHT NORTHERLY
WINDS WILL CONTINUE FREEZE WARNING FOR SHERIDAN COUNTY AND FROST
ADVISORY INTO THE WESTERN SANDHILLS. CLEARING SKIES THIS MORNING AND
PRECIPITATION ENDING AROUND NOON. MOST AREAS WILL SEE TEMPERATURES
IN THE 50S THIS AFTERNOON.
TONIGHT THE SURFACE HIGH WILL MOVE INTO SOUTH CENTRAL NEBRASKA WITH
SURFACE WINDS OVER WESTERN NEBRASKA FROM THE SOUTH UNDER CLEAR
SKIES. TEMPERATURES INTO THE 30S. HAVE ISSUED A FROST ADVISORY FROM
NORTH PLATTE TO BROKEN BOW FOR EARLY SATURDAY MORNING WITH PATCHY
FROST ALONG THE NORTH PLATTE RIVER VALLEY FROM NORTH PLATTE INTO THE
PANHANDLE. THE NORTHERN SANDHILLS LOOK TO STAY IN THE UPPER 30S FOR
LOWS AS 850MB TEMPERATURES WARM OVER NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 337 AM CDT FRI SEP 12 2014
MODELS CONTINUE TO SHOW DECENT AGREEMENT FROM THE WEEKEND THROUGH
MUCH OF NEXT WEEK...LEADING TO FAIR TO GOOD CONFIDENCE IN THIS
FORECAST PACKAGE. THE UPPER LEVEL PATTERN WILL MODERATE OVER THE
NEXT FEW DAYS AND INTO THE FIRST PART OF NEXT WEEK...HOWEVER THE
LOCAL AREA WILL REMAIN UNDER THE INFLUENCE OF NORTHWEST FLOW UNTIL
LATER IN THE FORECAST PERIOD /WEDNESDAY AND THURSDAY/. AT THIS
TIME RIDGING LOOKS TO BUILD IN OVER THE PLAINS AS A LARGE-SCALE
TROUGH PUSHES ONTO THE WEST COAST.
BEGINNING ON SATURDAY...HIGH PRESSURE AT THE SURFACE WILL BE
LOCATED EAST OF THE AREA...WITH THE AXIS FROM CENTRAL KANSAS INTO
WISCONSIN. RETURN SOUTHERLY FLOW WILL BE IN PLACE THROUGH THE DAY
OVER MUCH OF THE AREA WHICH WILL ALLOW WARM AIR ADVECTION TO TAKE
PLACE AS 850MB TEMPERATURES RISE 10 TO 13 DEGREES IN THE 24 HOURS
ENDING AT 00Z SUNDAY. THAT BEING SAID...850MB TEMPERATURES WILL
ONLY RANGE FROM 8C TO 16C AT THAT TIME...LEAVING TEMPERATURES TO
REMAIN 10 TO 20 DEGREES BELOW NORMAL ON SATURDAY.
SATURDAY NIGHT AND SUNDAY WILL SEE ANOTHER INFLUX OF COLDER AIR
COMING IN FROM THE NORTH AS A COLD FRONT TIED TO AN UPPER LEVEL
SHORTWAVE TROUGH MOVING ACROSS THE DAKOTAS PUSHES ACROSS
NEBRASKA. THIS WILL LEAD TO CONTINUED BELOW NORMAL TEMPERATURES.
LIGHT WINDS SATURDAY NIGHT WILL ALLOW THE BOUNDARY LAYER TO
DECOUPLE AND WITH DRY AIR IN PLACE TO PROMOTE MOSTLY CLEAR
SKIES...EXPECTING DECENT RADIATIONAL COOLING...WITH LOWS FALLING
TO THE UPPER 30S TO MID 40S. ON SUNDAY 60S AND LOW 70S ARE LIKELY
FOR MUCH OF THE FORECAST AREA...WHILE AREAS ACROSS FAR SOUTHWEST
NEBRASKA COULD SEE MID TO UPPER 70S AS PLENTIFUL SUNSHINE IS
EXPECTED AND THE FRONT LAYS UP JUST NORTH OF THOSE AREAS TO KEEP THE
WARMER AIR IN PLACE. MUCH OF THE AREA WILL BE UNDER LARGE SCALE
SUBSIDENCE AS THE STATE SITS BETWEEN THE CONVERGENCE OF THE POLAR
AND TROPICAL JETS. THE POLAR JET MAY DIP SOUTH ENOUGH TO BRING
SOME ENHANCED LIFT TO NORTH CENTRAL NEBRASKA AS IT WOULD BE IN THE
RIGHT ENTRANCE REGION OF THE JET STREAK ON SUNDAY. HAVE INCLUDED A
LOW CHANCE FOR RAIN IN THESE AREAS FOR SUNDAY.
A SECOND SHORTWAVE TROUGH WILL BE RIGHT BEHIND THE SATURDAY SYSTEM
WHICH IS LOOKING TO BE STRONGER AND WILL DIG FROM THE DAKOTAS INTO
THE MID MISSISSIPPI RIVER VALLEY SUNDAY NIGHT AND MONDAY. THERE IS
SOME DIFFERENCES IN TIMING WITH THE PASSAGE OF THIS IMPULSE OF
ENERGY...HOWEVER AS IT MOVES THROUGH...WITH A COLD FRONT SITUATED
WEST TO EAST ACROSS KANSAS AND HIGH PRESSURE BUILDING SOUTHEAST
FROM THE NORTHERN HIGH PLAINS AN AREA OF CONVERGENCE WILL EXIST
ROUGHLY ALONG THE NEBRASKA/KANSAS BORDER. EASTERLY UPSLOPE FLOW IN
THE LOW LEVELS WILL BRING MORE MOIST AIR INTO THIS AREA AND CROSS
SECTIONS SHOW ENOUGH LIFT TO PRODUCE PRECIPITATION AS THE SYSTEM
MOVES THROUGH. THE NAM AND ECMWF ARE A BIT QUICKER THAN THE GFS
AND PRODUCE THE RAIN SUNDAY NIGHT...WHILE THE GFS WOULD INCLUDE
THE SHOWERS DURING THE DAY MONDAY. HEDGED TOWARDS THE FASTER
SOLUTIONS SO ADDED SHOWER AND ISOLATED THUNDER CHANCES FOR SUNDAY
NIGHT IN THE SOUTHERN COUNTIES. THIS RAIN WILL PUSH SOUTH THROUGH
THE DAY MONDAY AS THE SURFACE HIGH MOVES SOUTHEAST TO BRING MORE
DRY AIR INTO THE AREA...LEAVING A DRY FORECAST FOR MONDAY.
THE REMAINDER OF THE WEEK WILL SEE A FEW PERIODIC CHANCES FOR RAIN
AS SEVERAL WEAK SHORTWAVE TROUGHS MOVE THROUGH THE QUICK NORTHWEST
FLOW TO BRING FAVORABLE CONDITIONS FOR SOME RAIN OR THUNDERSTORMS
ACROSS PORTIONS OF THE AREA. CONFIDENCE ON TIMING OF THESE SYSTEMS
IS NOT HIGH...BUT DO BELIEVE THERE WILL BE SCATTERED SHOWERS AND
STORMS FROM TIME TO TIME THROUGH THE NEXT WEEK DESPITE WARMING
TEMPERATURES AS THE UPPER LEVEL RIDGE BUILDS INTO THE PLAINS.
SPEAKING OF TEMPERATURES...EXPECT A SLOW MODERATION OF
TEMPERATURES THROUGH THE FIRST HALF OF NEXT WEEK AS THE NORTHWEST
FLOW KEEPS COOLER AIR ACROSS THE AREA. BUT BY THURSDAY...850MB
TEMPERATURES RISE BACK INTO THE LOW 20S...SO LOOKING FOR A RETURN
TO NEAR TO ABOVE NORMAL TEMPERATURES WHICH ARE NEAR 80 DEGREES FOR
HIGHS AND 50 DEGREES FOR LOWS AT THIS TIME OF THE YEAR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1245 PM CDT FRI SEP 12 2014
CLOUDY TO MOSTLY CLOUDY SKIES THIS AFTERNOON WITH POCKETS OF MVFR
LIFTING TO WIDESPREAD VFR THRU THE EARLY AFTERNOON HOURS. HIGH
PRESSURE BUILDS IN WITH SKIES BECOMING SKC TOWARDS SUNSET AND
CONTINUING OVERNIGHT. WINDS DECOUPLE AND BECOME LIGHT AND
VARIABLE OVERNIGHT...HOWEVER LOCALLY SOUTHERLY WINDS OF 5 TO 10
KTS POSSIBLE. TOMORROW MORNING SKIES CONTINUE TO BE SKC WITH
SOUTHERLY WINDS GUSTING TO AROUND 15 KTS ONCE THE BL BEGINS TO
MIX.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 4 AM TO 10 AM CDT SATURDAY FOR NEZ028-029-
038-059-071.
&&
$$
UPDATE...MASEK
SYNOPSIS...POWER
SHORT TERM...POWER
LONG TERM...BROOKS
AVIATION...MASEK
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1023 AM CDT FRI SEP 12 2014
.SYNOPSIS...
ISSUED AT 337 AM CDT FRI SEP 12 2014
STRONG HIGH HOLDS OVER THE SOUTHERN CONUS. MAINLY ZONAL FLOW FROM
THE MISSOURI VALLEY THROUGH THE EAST COAST. PROGRESSIVE TROUGH OVER
THE NORTHERN PLAINS AND WEAK RIDGING INTO THE PACIFIC NORTHWEST.
&&
.UPDATE...
ISSUED AT 1021 AM CDT FRI SEP 12 2014
MORNING TEMPS ON THE RISE SO ALLOWED FROST/FREEZE HEADLINE TO
EXPIRE ACROSS THE NORTHWEST. NO CHANGE TO THE FROST HEADLINE FOR
THE SOUTHEAST CWA TONIGHT. COLD AIR ALOFT SHOULD COMBINE WITH
WARMING TEMPS ACROSS N CENTRAL...AS SKIES ARE CLEARING THERE TO
PRODUCE STEEP AFTERNOON LAPSE RATES. CLOUDS SHOULD QUICKLY FORM
AND EVEN COULD SEEM SOME SPRINKLES OR LIGHT RAIN SHOWERS. NAM AND
THE HRRR SUPPORT THE LIGHT RAIN SHOWERS PRODUCING SOME POCKETS OF
QPF.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT FRI SEP 12 2014
MODELS IN GOOD AGREEMENT AND WILL USE BLEND FOR THE FORECAST. MAIN
FORECAST CONCERN WILL BE ENDING OF PRECIPITATION AND PTYPE WITH
HIGHLIGHTS FOR FROST IN THE NORTHWEST THIS MORNING AND THEN FROST IN
THE FORECAST EARLY SATURDAY MORNING.
PRECIPITATION SOUTH OF A LINE FROM AINSWORTH TO OSHKOSH THIS MORNING.
MOST AREAS REPORTING RAIN THIS MORNING BUT SOME AREAS OF DRIZZLE AND
SIDNEY REPORTING SNOW WITH TEMPERATURES RIGHT AROUND FREEZING.
CEILINGS LIFTING TO THE NORTH AND SOME CLEARING OVER NORTHWEST SOUTH
DAKOTA. CLEARING LINE IS MOVING TO THE SOUTHEAST AROUND 20 KTS AND
SHOULD BE THROUGH KVTN MID MORNING. 1037MB SURFACE HIGH CENTERED
OVER KCDR THIS MORNING WITH 850MB TEMPERATURES AROUND -1C.
TEMPERATURES OVER NORTHWEST IN THE MID 30S WITH LIGHT NORTHERLY
WINDS WILL CONTINUE FREEZE WARNING FOR SHERIDAN COUNTY AND FROST
ADVISORY INTO THE WESTERN SANDHILLS. CLEARING SKIES THIS MORNING AND
PRECIPITATION ENDING AROUND NOON. MOST AREAS WILL SEE TEMPERATURES
IN THE 50S THIS AFTERNOON.
TONIGHT THE SURFACE HIGH WILL MOVE INTO SOUTH CENTRAL NEBRASKA WITH
SURFACE WINDS OVER WESTERN NEBRASKA FROM THE SOUTH UNDER CLEAR
SKIES. TEMPERATURES INTO THE 30S. HAVE ISSUED A FROST ADVISORY FROM
NORTH PLATTE TO BROKEN BOW FOR EARLY SATURDAY MORNING WITH PATCHY
FROST ALONG THE NORTH PLATTE RIVER VALLEY FROM NORTH PLATTE INTO THE
PANHANDLE. THE NORTHERN SANDHILLS LOOK TO STAY IN THE UPPER 30S FOR
LOWS AS 850MB TEMPERATURES WARM OVER NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 337 AM CDT FRI SEP 12 2014
MODELS CONTINUE TO SHOW DECENT AGREEMENT FROM THE WEEKEND THROUGH
MUCH OF NEXT WEEK...LEADING TO FAIR TO GOOD CONFIDENCE IN THIS
FORECAST PACKAGE. THE UPPER LEVEL PATTERN WILL MODERATE OVER THE
NEXT FEW DAYS AND INTO THE FIRST PART OF NEXT WEEK...HOWEVER THE
LOCAL AREA WILL REMAIN UNDER THE INFLUENCE OF NORTHWEST FLOW UNTIL
LATER IN THE FORECAST PERIOD /WEDNESDAY AND THURSDAY/. AT THIS
TIME RIDGING LOOKS TO BUILD IN OVER THE PLAINS AS A LARGE-SCALE
TROUGH PUSHES ONTO THE WEST COAST.
BEGINNING ON SATURDAY...HIGH PRESSURE AT THE SURFACE WILL BE
LOCATED EAST OF THE AREA...WITH THE AXIS FROM CENTRAL KANSAS INTO
WISCONSIN. RETURN SOUTHERLY FLOW WILL BE IN PLACE THROUGH THE DAY
OVER MUCH OF THE AREA WHICH WILL ALLOW WARM AIR ADVECTION TO TAKE
PLACE AS 850MB TEMPERATURES RISE 10 TO 13 DEGREES IN THE 24 HOURS
ENDING AT 00Z SUNDAY. THAT BEING SAID...850MB TEMPERATURES WILL
ONLY RANGE FROM 8C TO 16C AT THAT TIME...LEAVING TEMPERATURES TO
REMAIN 10 TO 20 DEGREES BELOW NORMAL ON SATURDAY.
SATURDAY NIGHT AND SUNDAY WILL SEE ANOTHER INFLUX OF COLDER AIR
COMING IN FROM THE NORTH AS A COLD FRONT TIED TO AN UPPER LEVEL
SHORTWAVE TROUGH MOVING ACROSS THE DAKOTAS PUSHES ACROSS
NEBRASKA. THIS WILL LEAD TO CONTINUED BELOW NORMAL TEMPERATURES.
LIGHT WINDS SATURDAY NIGHT WILL ALLOW THE BOUNDARY LAYER TO
DECOUPLE AND WITH DRY AIR IN PLACE TO PROMOTE MOSTLY CLEAR
SKIES...EXPECTING DECENT RADIATIONAL COOLING...WITH LOWS FALLING
TO THE UPPER 30S TO MID 40S. ON SUNDAY 60S AND LOW 70S ARE LIKELY
FOR MUCH OF THE FORECAST AREA...WHILE AREAS ACROSS FAR SOUTHWEST
NEBRASKA COULD SEE MID TO UPPER 70S AS PLENTIFUL SUNSHINE IS
EXPECTED AND THE FRONT LAYS UP JUST NORTH OF THOSE AREAS TO KEEP THE
WARMER AIR IN PLACE. MUCH OF THE AREA WILL BE UNDER LARGE SCALE
SUBSIDENCE AS THE STATE SITS BETWEEN THE CONVERGENCE OF THE POLAR
AND TROPICAL JETS. THE POLAR JET MAY DIP SOUTH ENOUGH TO BRING
SOME ENHANCED LIFT TO NORTH CENTRAL NEBRASKA AS IT WOULD BE IN THE
RIGHT ENTRANCE REGION OF THE JET STREAK ON SUNDAY. HAVE INCLUDED A
LOW CHANCE FOR RAIN IN THESE AREAS FOR SUNDAY.
A SECOND SHORTWAVE TROUGH WILL BE RIGHT BEHIND THE SATURDAY SYSTEM
WHICH IS LOOKING TO BE STRONGER AND WILL DIG FROM THE DAKOTAS INTO
THE MID MISSISSIPPI RIVER VALLEY SUNDAY NIGHT AND MONDAY. THERE IS
SOME DIFFERENCES IN TIMING WITH THE PASSAGE OF THIS IMPULSE OF
ENERGY...HOWEVER AS IT MOVES THROUGH...WITH A COLD FRONT SITUATED
WEST TO EAST ACROSS KANSAS AND HIGH PRESSURE BUILDING SOUTHEAST
FROM THE NORTHERN HIGH PLAINS AN AREA OF CONVERGENCE WILL EXIST
ROUGHLY ALONG THE NEBRASKA/KANSAS BORDER. EASTERLY UPSLOPE FLOW IN
THE LOW LEVELS WILL BRING MORE MOIST AIR INTO THIS AREA AND CROSS
SECTIONS SHOW ENOUGH LIFT TO PRODUCE PRECIPITATION AS THE SYSTEM
MOVES THROUGH. THE NAM AND ECMWF ARE A BIT QUICKER THAN THE GFS
AND PRODUCE THE RAIN SUNDAY NIGHT...WHILE THE GFS WOULD INCLUDE
THE SHOWERS DURING THE DAY MONDAY. HEDGED TOWARDS THE FASTER
SOLUTIONS SO ADDED SHOWER AND ISOLATED THUNDER CHANCES FOR SUNDAY
NIGHT IN THE SOUTHERN COUNTIES. THIS RAIN WILL PUSH SOUTH THROUGH
THE DAY MONDAY AS THE SURFACE HIGH MOVES SOUTHEAST TO BRING MORE
DRY AIR INTO THE AREA...LEAVING A DRY FORECAST FOR MONDAY.
THE REMAINDER OF THE WEEK WILL SEE A FEW PERIODIC CHANCES FOR RAIN
AS SEVERAL WEAK SHORTWAVE TROUGHS MOVE THROUGH THE QUICK NORTHWEST
FLOW TO BRING FAVORABLE CONDITIONS FOR SOME RAIN OR THUNDERSTORMS
ACROSS PORTIONS OF THE AREA. CONFIDENCE ON TIMING OF THESE SYSTEMS
IS NOT HIGH...BUT DO BELIEVE THERE WILL BE SCATTERED SHOWERS AND
STORMS FROM TIME TO TIME THROUGH THE NEXT WEEK DESPITE WARMING
TEMPERATURES AS THE UPPER LEVEL RIDGE BUILDS INTO THE PLAINS.
SPEAKING OF TEMPERATURES...EXPECT A SLOW MODERATION OF
TEMPERATURES THROUGH THE FIRST HALF OF NEXT WEEK AS THE NORTHWEST
FLOW KEEPS COOLER AIR ACROSS THE AREA. BUT BY THURSDAY...850MB
TEMPERATURES RISE BACK INTO THE LOW 20S...SO LOOKING FOR A RETURN
TO NEAR TO ABOVE NORMAL TEMPERATURES WHICH ARE NEAR 80 DEGREES FOR
HIGHS AND 50 DEGREES FOR LOWS AT THIS TIME OF THE YEAR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 750 AM CDT FRI SEP 12 2014
PRECIPITATION WILL END OVER WESTERN NEBRASKA THIS MORNING.SOME
AREAS OF LIGHT RAIN AND DRIZZLE CONTINUE OVER SOUTHWEST NEBRASKA
SOUTH OF A LINE FROM BROKEN BOW TO IMPERIAL. LOW CLOUDS CEILINGS
IN IFR CATEGORIES WILL BEGIN TO LIFT EARLY THIS MORNING AS DRY AIR
MOVES EAST. VFR CONDITIONS EXPECTED AFTER 18Z OVER ALL OF WESTERN
AND NORTH CENTRAL NEBRASKA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 4 AM TO 10 AM CDT SATURDAY FOR NEZ028-029-
038-059-071.
&&
$$
UPDATE...MASEK
SYNOPSIS...POWER
SHORT TERM...POWER
LONG TERM...BROOKS
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1030 AM EDT FRI SEP 12 2014
.SYNOPSIS...
CLEARING SKIES...COOLER AND DRIER WEATHER IS EXPECTED TODAY WITH
HIGHS IN THE UPPER 50S TO MID 60S. TEMPERATURES WILL REMAIN EARLY
OCTOBER-LIKE THIS WEEKEND. SHOWERS WILL MOVE IN SATURDAY AFTERNOON
AND NIGHT AS AN AREA OF LOW PRESSURE MOVES ACROSS THE REGION. HIGH
PRESSURE WILL BRING A RETURN OF DRY WEATHER WITH SOME SUNSHINE ON
SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1025 AM EDT FRIDAY...WENT MORE PESSIMISTIC ON CLOUD COVER
AND THUS COOLER MAX TEMPS THIS AFTERNOON. VISIBLE SATELLITE
SHOWING SOLID CLOUD COVER AND MORE LOW LEVEL MOISTURE TO THE NORTH
STREAMING TO THE SOUTH. EXCEPTION IS IN SOUTHERN VERMONT AND
SOUTHERN ESSEX COUNTY NY WHERE DOWNSLOPE FLOW IS CREATING SOME
BREAKS IN THE CLOUD COVER. USED RUC13 925 MB RH FIELD TO POPULATE
SKY COVER THROUGH THE AFTERNOON AND THEN BLENDED INTO PREVIOUS
FORECAST TOWARD SUNSET. EVENTUALLY DRIER LAYER ABOVE THE CLOUDS
WILL MIX DOWNWARD, BUT WILL BE A STRUGGLE AS OVERCAST INHIBITS
SURFACE HEATING NEEDED TO OVERTURN THE BOUNDARY LAYER. UPDATED
TEMPS WITH LATEST LAV GUIDANCE WHICH DROPS MAX TEMPS A COUPLE
DEGREES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
AS OF 419 AM EDT FRIDAY...
IT WILL BE COOL ONCE AGAIN TONIGHT...STARTING OUT CLEAR BUT SOME
INCREASE IN CLOUDS OVERNIGHT WILL KEEP LOWS MOSTLY IN THE LOWER TO
MID 40S...EXCEPT FOR SOME 30S IN THE ADIRONDACKS AND NORTHEAST
VERMONT. MOST PLACES SHOULD ONCE AGAIN AVOID A FROST THOUGH HAVE
PUT A FEW GRIDS IN WITH PATCHY FROST AROUND SLK AND CANAAN.
ON SATURDAY...A WEAK (~1020 MB) LOW PRESSURE (1020 MB) DEVELOPS
OVER THE EASTERN GREAT LAKES AND MOVES UP THE ST. LAW VALLEY TO
NEAR CYUL BY 00Z SUNDAY IN RESPONSE TO A SHORT WAVE WITH 12 DM HGT
FALL NEAR CYUL AT 00Z SUN
SOME MODERATE QG FORCING WITH WARM ADVECTION AT 850-500 MB AND PV
ADVECTION ALOFT AND DIVERGENCE IN THE RIGHT ENTRANCE REGION OF 250
MB JET TO DRIVE VERTICAL MOTION. THIS COMBINED WITH SUFFICIENT
MOISTURE ADVECTION OF UP TO AN INCH OF PRECIPITABLE WATER WILL BE
ENOUGH TO PRODUCE SOME LIGHT RAIN/SHOWERS...WHICH WILL DEVELOP
FROM WEST TO EAST DURING THE AFTERNOON AND THEN TAPER OFF IN
SIMILAR FASHION SATURDAY NIGHT. PRECIPITATION AMOUNTS WILL BE
GENERALLY LIGHT...WITH 0.10-0.35 INCHES EXPECTED.
IT WILL CONTINUE COOL SAT BUT PERHAPS A FEW DEGREES COOLER THAN
TODAY WITH THICKENING CLOUD COVER AND DEPENDING ON WHEN THE RAIN
ARRIVES. 925 TEMP AGAIN AROUND +8C FOR HIGHS IN THE UPPER 50S TO
LOWER 60S.
COLD ADVECTION AND UPSLOPE FLOW BEHIND THE SYSTEM SATURDAY NIGHT
INTO EARLY SUNDAY WILL CONTINUE CLOUDS AND SOME CHANCE OF SHOWERS
MAINLY IN THE MOUNTAINS. LOW TEMPS IN THE 40S.
HIGH PRESSURE BUILDS IN SLOWLY FOR SUNDAY WITH RISING HEIGHTS AND
WEAK SHORTWAVE RIDGING BUT IT MAY UNTIL AFTERNOON SOMETIME TO
CLEAR OUT THE CLOUDS. 925 TEMPS A DEGREE COOLER SO HIGHS MID 50S
TO LOWER 60S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 435 AM EDT FRIDAY...ECMWF AND GFS MODELS IN GOOD AGREEMENT
IN SHOWING A RIDGE OF HIGH PRESSURE OVER THE REGION SUNDAY NIGHT
AND MONDAY WITH FAIR AND DRY WEATHER EXPECTED. LATE MONDAY NIGHT
INTO TUESDAY...MODELS SHOWING AN UPPER SHORTWAVE WILL DIG EAST-
SOUTHEAST FROM THE GREAT LAKES AND BRING A CHANCE OF RAIN SHOWERS
TO THE NORTH COUNTRY LATE MONDAY NIGHT INTO TUESDAY. GFS MODEL IS
FASTER THAN THE ECMWF MODEL IN BRINGING SHOWERS INTO THE REGION
LATE MONDAY NIGHT AND TUESDAY...AND ALSO WANTS TO END SHOWER
ACTIVITY EARLIER ON TUESDAY THAN THE ECMWF. ECMWF HAS MORE SHARPER
UPPER SHORTWAVE COMING FROM THE GREAT LAKES AND ALSO KEEPS IN
SHOWER ACTIVITY IN ACROSS THE REGION LONGER ON TUESDAY. HAVE GONE
WITH THE TIMING OF THE ECMWF FOR SHOWERS FOR LATE MONDAY NIGHT AND
TUESDAY. HIGH PRESSURE WILL THEN BUILD EAST FROM THE GREAT LAKES
AND OHIO VALLEY TUESDAY NIGHT AND WILL REMAIN OVER THE NORTH
COUNTRY THROUGH THURSDAY WITH FAIR AND DRY WEATHER EXPECTED. BELOW
NORMAL TEMPERATURES EXPECTED THROUGH THE PERIOD...WITH HIGHS
MAINLY IN THE 60S.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
THROUGH 06Z SATURDAY...SATELLITE LOOP AS OF 0600Z FRIDAY SHOWING
PLENTY OF LOW CLOUD COVER ACROSS THE REGION WITH MAINLY MVFR/VFR
CEILINGS. A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION TODAY.
EXPECTING CONDITIONS TO BECOME VFR THROUGHOUT BY 18Z FRIDAY. ALSO EXPECTING
LOW CLOUD COVER TO BECOME SCATTERED BY 18Z AS DRIER AIR WORKS INTO
THE REGION. EXPECTING SURFACE WINDS TO DIMINISH TO LESS THAN 10
KNOTS BY 14Z FRIDAY.
OUTLOOK 06Z SATURDAY THROUGH TUESDAY...
06Z-18Z SATURDAY...VFR EXCEPT FOR LOCAL IFR IN ANY PATCHY LATE
NIGHT FOG AT SLK AND MPV.
18Z SATURDAY - 12Z SUNDAY...MVFR POSSIBLE IN SHOWERS
12Z SUNDAY - 12Z TUESDAY...VFR EXCEPT POSSIBLE IFR IN LATE NIGHT
FOG AT SLK AND MPV.
12Z TUESDAY ONWARD...MVFR POSSIBLE IN SHOWERS.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...SISSON
NEAR TERM...HANSON
SHORT TERM...SISSON
LONG TERM...WGH
AVIATION...WGH/NASH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
307 PM EDT FRI SEP 12 2014
.SYNOPSIS...
A COLD FRONT WILL BRING UNSETTLED WEATHER THROUGH THE WEEKEND. THE
FRONT WILL WEAKEN ON MONDAY BUT MOISTURE WILL LINGER FOR A
SCATTERING OF SHOWERS MONDAY. ANOTHER COLD FRONT SHOULD AFFECT THE
REGION ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM FRIDAY...CONVECTIVE PROCESSES WELL UNDERWAY WITH SLOW
MOVING HARD-HITTING CELLS SMACKING PAVEMENT...YARDS AND FIELDS
WITH SCATTERED TORRENTIAL RAINFALL CORES. THE SEA-BREEZE FRONT
WAS NEARLY FILLED IN WITH TOWERING CUMULUS CELLS...AND ROUGHLY
ALONG A QUASI-STATIONARY FRONTAL BOUNDARY DRAPED ACROSS OUR
SE NC INTERIOR NORTHERN TIER. THE BOUNDARY EXTENDED SOUTHWEST
INTO CENTRAL SC WHERE HEAVY RAIN CORES WERE DRIFTING SLOWLY E.
BECAUSE OF THE TENUOUS UPPER SUPPORT WITH THIS SYSTEM...DIURNAL
HEATING AND COOLING DIURNAL TRENDS WILL LIKELY REMAIN SIGNIFICANT
INFLUENCES ON PCPN GENERATION AND RAIN-RATES. HIGH PWATS AND
OUTFLOWS AS WELL AS THE SEA BREEZE CONVERGENCE ITSELF WILL SUSTAIN
STORMS INTO THE EVENING HOURS. A FEW IMPULSES ALOFT TRAVERSING THE
SFC BOUNDARY WILL LIKELY KEEP A CHANCE OF SHRA/TSTMS GOING EVEN
INTO THE OVERNIGHT...BUT OVERALL RAIN-RATES AND STORM COVERAGE IS
EXPECTED TO SHOW SOME SCALING BACK AS SURFACE HEATING TAILS OFF
AND IS TAPPED INTO OVER THE NEXT 8 HOURS. TROPICAL MOISTURE AND
WEAK STEERING WINDS WILL ALLOW SOME AREAS TO EXPERIENCE LOCALIZED
FLOODING AT TIMES THROUGH EARLY SATURDAY.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...ANOTHER FAIRLY UNSETTLED AFTERNOON IN STORE FOR
THE REGION SATURDAY AS COLD FRONT ENTERS THE COASTAL PLAIN IN THE
PRESENCE OF FAIRLY DEEP TROPICAL MOISTURE. THE MOST WIDESPREAD
COVERAGE WILL BE OVER NWRN ZONES WHICH WILL BE MOST PROXIMAL TO THE
BOUNDARY...PERHAPS RADAR COVERAGE NOT UNLIKE THAT OF THIS AFTERNOON.
WITH A MORE CLOUDY START COMPARED TO TODAY AFTERNOON TEMPERATURES
WILL NOT GROW AS HOT AND TEND TO BE QUITE SEASONABLE. PRECIPITABLE
WATER REMAINS ABOVE 2 INCHES WHILE STORM MOTION REMAINS BELOW 5KT SO
CHANCE FOR HEAVY DOWNPOURS REMAINS INTACT. RAIN CHANCES WILL HAVE A
HARD TIME DIPPING MUCH LOWER THAN LOW END CHANCE RANGE SATURDAY
NIGHT AS THE FRONT MOVES ATOP OF THE FORECAST AREA...ALTHOUGH THE
LOSS OF DAYTIME HEATING SHOULD DIMINISH THEIR INTENSITY AND THE
HEAVY RAIN THREAT. WE WIND UP ON THE OTHER SIDE OF THE FRONT ON
SUNDAY AS IT REMAINS NEARLY STALLED TO OUR SOUTH AND EAST. RAIN
CHANCES WILL BE SHIFTED SOUTH AND EAST ACCORDINGLY AND THE HEAVY
RAIN THREAT WILL BE RELATIVELY MITIGATED. SUNDAY AFTERNOON MAY OFFER
UP A RANGE OF HIGH TEMPERATURES FROM NORTH TO SOUTH FROM THE UPPER
70S TO THE MID 80S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 3 PM FRIDAY...WEAKENING FRONT STALLED IN THE AREA AT THE START
OF THE PERIOD AND DEEP TROPICAL MOISTURE ENSURE THE FIRST HALF OF
NEXT WEEK REMAIN UNSETTLED. PRECIPITABLE WATER VALUES AROUND 2
INCHES MON AND TUE IN A MODERATELY UNSTABLE AIRMASS SHOULD LEAD TO
SHOWER AND THUNDERSTORM DEVELOPMENT. PLAN TO CARRY CHC POP WITH A
DIURNAL DISTRIBUTION. THE LACK OF FORCING ALOFT SHOULD LEAD TO A
DECREASE IN COVERAGE/ACTIVITY OVERNIGHT BUT DO NOT THINK STORMS WILL
COMPLETELY DISSIPATE. STORM MOTIONS WILL REMAIN 10 KT OR LESS WHICH
WILL MAINTAIN FLOODING POTENTIAL.
A STRONGER COLD FRONT WILL DROP IN FROM THE NORTHWEST MID WEEK. THIS
FRONT HAS A MORE DEFINED TROUGH BEHIND IT WHICH WILL PUSH THE
BOUNDARY SOUTH OF THE AREA BY THE END OF THE WEEK. HOWEVER THERE IS
STILL SOME UNCERTAINTY AS TO HOW FAR SOUTH THIS FRONT MOVES BEFORE
STALLING. ECMWF HAS THE FRONT FARTHER SOUTH...SO DOES WPC...WHILE
THE GFS KEEPS THE FRONT CLOSER TO THE CAROLINAS. BOTH MEDIUM RANGE
SOLUTIONS DEVELOP A WEAK LOW ON THE FRONT AND LIFT IT NORTH...THOUGH
TIMING IS DIFFERENT. ECMWF SOLUTION WOULD PRODUCE SLIGHT CHC TO LOW
CHC OF PRECIP THROUGH THU...MAINLY ALONG THE COAST...WITH DRYING
FRI. GFS IS WETTER WITH HIGH CHC TO LIKELY POP THROUGH THE END OF
THE PERIOD FOR MUCH OF THE FORECAST AREA. PREVIOUS FORECASTS HAVE
BEEN IN LINE WITH THE DRIER ECMWF/WPC SOLUTION AND AT THIS POINT CAN
SEE NO REASON TO MAKE A CHANGE. CONFIDENCE REMAINS LOW SO
SIGNIFICANT CHANGES IN LATER FORECASTS IS STILL A POSSIBILITY.
TEMPERATURE RANGES EARLY IN THE PERIOD WILL BE ON THE NARROW END
WITH CLOUD COVER AND PRECIP KEEPING HIGHS NEAR TO SLIGHTLY BELOW
CLIMO BUT HELPING HOLD LOWS SEVERAL DEGREES ABOVE CLIMO. PASSAGE OF
FRONT MID WEEK WILL BRING BELOW CLIMO TEMPS FOR THE END OF THE WEEK.
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 18Z...THE HRRR MODEL HAS PRETTY ROBUST SEA BREEZE CONVECTION
THIS AFTERNOON. DO BELIEVE THE RESULTANT WILL BE THE FOCUS...BUT
ONLY SCATTERED CONVECTION EXPECTED. BRIEF PERIODS OF LOW
VISIBILITIES EXPECTED IN THE HEAVIER SHOWERS AND ISOLATED THUNDER.
STEERING FLOW WILL LIKELY KEEP MOST OF THE ACTIVITY NEAR THE
COAST...REACHING INLAND AFTER 20Z. TONIGHT COLD FRONT WILL BE
THROUGH MOST OF THE CWA...WITH AN IFR CEILING EXPECTED AFTER
MIDNIGHT...POSSIBLY THROUGH MID MORNING. FRONTAL BOUNDARY WILL STILL
BE OVER THE AREA...WITH CONVECTION EXPECTED TO REFIRE BY LATE
MORNING. LITTLE TO NO PRESSURE GRADIENT...SO WINDS WILL BE VARIABLE.
EXTENDED OUTLOOK...A GOOD CHANCE FOR SHOWERS/TSTMS AND TEMPO MVFR
THROUGH THE WEDNESDAY WITH A STALLED COLD FRONT.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 3 PM FRIDAY...OUTSIDE OF TSTMS NO REAL PROBLEMS EXPECTED ON
THE WATERS WITH LIGHT WINDS OVERALL AND SEAS 2 FEET OR LESS...AS A
WEAK FRONTAL BOUNDARY REMAINS IN VICINITY OF THE AREA. MOST STORMS
SHOULD STAY OVER LAND BUT TONIGHT CELLS MAY BEGIN TO FAVOR THE
0-20 NM WATERS. SEAS AROUND 2 FEET IN A MIX OF SE WAVES 1-1.5 FT
EVERY 8-9 SECONDS AND S WAVES 0.5-1 FT EVERY 3-4 SECONDS. WITHIN
TSTMS WINDS AND SEAS WILL BE LOCALLY AND SIGNIFICANTLY HIGHER.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...PREFRONTAL SOUTHWESTERLY FLOW ON SATURDAY SHOULD
REMAIN AT 10 KT PREVENTING SEAS FROM ATTAINING HEIGHTS MORE THAN 2
FT. LATE SATURDAY NIGHT AS THE FRONT DRAWS NEAR THE COAST THERE MAY
BE A GENTLE BACKING OF THE FLOW FOLLOWED BY A MORE PRECIPITOUS VEER
ON SUNDAY ASSOCIATED WITH ACTUAL FROPA. THE FRONT WILL NOT MOVE VERY
FAR TO OUR SOUTH BEFORE STALLING WHICH PRECLUDES MUCH OF A SURGE OF
HIGH PRESSURE AND THUS ANY HIGHER WINDS. THUS THE VEER TO ENE FLOW
APPEARS TO BE THE MAIN EFFECT OF THE FROPA AS WIND SPEEDS AND WAVE
HEIGHTS REMAIN UNCHANGED...ALTHOUGH WAVE PERIODS MAY SHORTEN UP A
BIT.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 3 PM FRIDAY...DIMINISHING NORTHERLY SURGE AT THE START OF THE
PERIOD WILL LEAVE LIGHT AND VARIABLE WINDS OVER THE WATERS FOR MUCH
OF MON AND TUE GIVEN PROXIMITY TO THE STALLED FRONT. ANOTHER COLD
FRONT WILL DROP IN FROM THE NORTHWEST DURING THE SECOND HALF OF THE
PERIOD. THIS FRONT IS MORE DEFINED AND SHOULD BE ACCOMPANIED BY A
STRONGER NORTHERLY SURGE LATER WED INTO WED NIGHT. WINDS WILL
APPROACH A SOLID 15 KT WED NIGHT WITH GUSTS AROUND 20 KT POSSIBLE.
SEAS 2 TO 3 FT FOR MUCH OF THE PERIOD WILL BUILD AS HIGH AS 5 FT AS
THE PERIOD ENDS DUE TO THE PROLONGED AND STEADILY INCREASING NATURE
OF THE NORTHERLY SURGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MBB
NEAR TERM...MJC
SHORT TERM...MBB
LONG TERM...III
AVIATION...DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
122 PM EDT FRI SEP 12 2014
.SYNOPSIS...
A COLD FRONT WILL APPROACH SLOWLY FROM THE NORTHWEST TODAY BEFORE
BECOMING STATIONARY ALONG THE COAST. UNSETTLED WEATHER AS A RESULT
WILL LIKELY PREVAIL AT TIMES THROUGH EARLY NEXT WEEK WITH SCATTERED
LOCALLY HEAVY RAIN SHOWERS AND THUNDERSTORMS. CANADIAN HIGH PRESSURE
IS EXPECTED TO EDGE INTO THE CAROLINAS NEXT WEEK...BRINGING COOLER
AIR INTO THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 955 AM FRIDAY...LONGER LOOP WATER VAPOR ANIMATIONS SHOW THE
APPROACHING FRONTAL SYSTEM HAS BEEN ENCOMPASSED BY DRY MID-LEVEL
AIR THROUGH MUCH OF ITS EVOLUTION AND PROGRESSION EASTWARD. EVEN
WITH PRECIPITABLE WATERS OF AROUND 2 INCHES CURRENTLY...12Z RAOBS
SHOW DRY SLABS CAPPING THE COLUMN INDUCING A DEGREE OF INHIBITION
THIS MORNING. AS A RESULT FULLY EXPECT DIURNAL HEATING TO PLAY A
SIGNIFICANT ROLE IN PCPN GENERATION LATER TODAY...PARTICULARLY AS
IMPLIED BY VSBL DATA...THAT SURFACE HEATING/INCREASING STABILITY
IS PRESENTLY UNDERWAY.
SURFACE ANALYSIS SHOWS A DEWPOINT BOUNDARY IS DIPPING SOUTHWARD
ACROSS VIRGINIA AT 14Z/10AM...WITH BALMY SW FLOW AND ELEVATED TD
VALUES SOUTH OF THIS BOUNDARY. PRESSURE ANALYSIS SUGGESTS THE COLD
FRONT IS POSITIONED FROM OBX NC TO PGV TO SOP TO CAE SC TO MCN GA.
INSOLATION AND DEEP MOISTURE AS THE CAP IS OVERCOME SHOULD HAVE
NO ISSUES IN CREATING CUMULO-NIMBUS CELLS IN THE AFTERNOON WHILE
STEERING WINDS APPEAR POISED TO DIRECT ACTIVITY SLUGGISHLY TO THE
EAST. THUS WITH A VAPOR LOADED COLUMN AND SLOW STORM MOTION A LOW-
END THREAT OF LOCALIZED FLOODING OR PONDING ON CONCRETE IS IN THE
CARDS THIS AFTERNOON AND TONIGHT. THE SEA BREEZE CONVERGENCE WILL
SERVE AS ADDED LOW-LEVEL FOCUS.
WILL NEED TO TAKE A CLOSER LOOK A MAX T TODAY. TRENDS ARE HEATING
UP QUICK BUT AT SOME POINT SUSPECT THE TEMP CURVES SHOULD LEVEL
OFF OR FLATTEN AS CU DEVELOPMENT AND CLOUD-TEAMING UNFOLDS. ANY
CHANGES WITH THE MORNING UPDATE WOULD BE TO RAISE CURRENT MAX T
NUMBERS POTENTIALLY A DEGREE OR TWO.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 330 AM FRIDAY...COLD FRONT WILL BE HUNG UP OVER THE
COASTAL CAROLINAS THROUGH THE WEEKEND KEEPING UNSETTLED WEATHER
AND REMAINING THE FOCAL POINT FOR CONVECTIVE DEVELOPMENT. A
SHORTWAVE RIDING AROUND VERY BROAD TROUGH EXTENDING DOWN FROM THE
GREAT LAKES WILL TRY AND NUDGE IT SOUTHWARD LATE SATURDAY INTO
SUNDAY BUT IT COMES UP AGAINST RIDGE TO THE SOUTH AND ENDS UP
REMAINING IN THE VICINITY STRETCHING OUT FROM W-SW TO E-NE NEAR
THE BORDER BETWEEN NORTH AND SOUTH CAROLINA. MAY GET SOME BREAKS
IN PCP THROUGH THE WEEKEND BUT IT LOOKS LIKE COLUMN WILL REMAIN
NEARLY SATURATED MOST OF THE TIME AND THEREFORE COUNTING ON PLENTY
OF CLOUD COVER AND PCP. MAY SEE WINDS FLUCTUATE AS COLD FRONT
MEANDERS ACROSS THE REGION BUT OVERALL GRADIENT REMAINS RELAXED
WITH LIGHT WINDS. LOOKS LIKE BEST CHC OF HEAVIER PCP WILL BE
FOCUSED OVER NC EARLIER IN THE WEEKEND AND THEN SHIFT OVER SC INTO
EARLY NEXT WEEK. PCP WATER VALUES REMAIN UP AROUND 2.25 INCHES
WITH ONLY A SLIGHT DROP OVER NC BY END OF WEEKEND. BEST SHORTWAVE
ENERGY AND JET DYNAMICS REMAIN NORTH OF AREA SAT AFTN AND
THEREFORE EXPECT STRONGEST CONVECTION TO REMAIN WELL NORTH OF
AREA...BUT FRONT WILL REMAIN FOCAL POINT FOR CONVECTION THROUGH
THE WEEKEND. QPF AMOUNTS SHOULD BE GREATER OVER NC ON
SAT...SHIFTING SOUTH AND CLOSER TO THE COAST BY SUNDAY.
MAXIMUM TEMPERATURES ARE EXPECTED TO REACH INTO THE LOWER TO
MIDDLE 80S EACH DAY WITH MINIMUM TEMPERATURES FALLING TO AROUND
70 DEGREES. BY SUNDAY COOLER AIR WILL BLEED IN FROM THE NORTH AS
BOUNDARY GETS PUSHED SOUTH. THEREFORE EXPECT TEMPS TO RUN BELOW 80
OVER PEE DEE REGION WITH PLENTY OF CLOUDS BOTH DAYS.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 330 AM FRIDAY...LINGERING COLD FRONT NEAR OR JUST SOUTH OF
LOCAL FORECAST AREA THE COASTAL CAROLINAS WILL WEAKEN MON INTO
TUES. SHOULD SEE COOL NORTHEASTERLY FLOW OVER MUCH OF THE AREA
EARLY MONDAY WITH W-SW FLOW RIDING OVER IT. THIS MAY CREATE A NICE
BLANKET OF STRATUS...BUT ALSO MAY HAVE ENOUGH CONVERGENCE ALONG
FRONT TO PRODUCE SOME CONVECTION. WILL DEPEND ON EXACT LOCATION OF
FRONT AND AT THIS POINT SOME UNCERTAINTY STILL EXISTS. MOISTURE
PROFILES DO SHOW OVERALL MOISTURE THROUGH THE COLUMN DIMINISHING
SLIGHTLY BUT STILL SEEING PCP WATER VALUES NOT DROPPING MUCH BELOW
2 INCHES THROUGH WED. OVERALL EXPECT PLENTY OF CLOUDS AND PROBABLY
LOWER END QPF AMOUNTS OVERALL BUT CAN NOT RULE OUT CONVECTIVE
DEVELOPMENT ALONG LINGERING FRONT. MAY EVEN SEE TEMPS INTO THE MID
80S MON AND TUES AS MID TO UPPER RIDGE RIDGE BUILDS SLIGHTLY
ACROSS THE AREA...BUT THESE TEMPS MAY END UP TOO HIGH IN THICKER
CLOUD COVER AND PCP.
BY WED INTO THURS THE BROAD UPPER TROUGH OVER THE GREAT LAKES INTO
CANADA WILL BEGIN TO SHIFT EAST DIGGING DOWN INTO THE SOUTHEAST.
THIS MAY PUSH A SECONDARY FRONT SOUTH AND MAY GIVE ENOUGH OF A
PUSH TO FINALLY CLEAR OUT THE WEATHER BUT LATEST GFS SHOWS A WAVE
OF LOW PRESSURE DEVELOPING ALONG THE THE FRONT WHICH MAY KEEP
UNSETTLED WEATHER OVER THE AREA FOR YET ANOTHER DAY. THE ECMWF
REMAINS MORE OPTIMISTIC PUSHING THE FRONT OFF SHORE WITH COOLER
AND DRIER HIGH PRESSURE BUILDING DOWN BEHIND IT.
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 18Z...THE HRRR MODEL HAS PRETTY ROBUST SEA BREEZE CONVECTION
THIS AFTERNOON. DO BELIEVE THE RESULTANT WILL BE THE FOCUS...BUT
ONLY SCATTERED CONVECTION EXPECTED. BRIEF PERIODS OF LOW
VISIBILITIES EXPECTED IN THE HEAVIER SHOWERS AND ISOLATED THUNDER.
STEERING FLOW WILL LIKELY KEEP MOST OF THE ACTIVITY NEAR THE
COAST...REACHING INLAND AFTER 20Z. TONIGHT COLD FRONT WILL BE
THROUGH MOST OF THE CWA...WITH AN IFR CEILING EXPECTED AFTER
MIDNIGHT...POSSIBLY THROUGH MID MORNING. FRONTAL BOUNDARY WILL STILL
BE OVER THE AREA...WITH CONVECTION EXPECTED TO REFIRE BY LATE
MORNING. LITTLE TO NO PRESSURE GRADIENT...SO WINDS WILL BE VARIABLE.
EXTENDED OUTLOOK...A GOOD CHANCE FOR SHOWERS/TSTMS AND TEMPO MVFR
THROUGH THE WEDNESDAY WITH A STALLED COLD FRONT.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 955 AM FRIDAY...DOCILE WIND FORECAST THIS PERIOD DUE TO A WEAK
SFC COLD FRONT DROPPING SE-WARD. THE SFC PG AHEAD OF THIS BOUNDARY
NOT ALL THAT IMPRESSIVE AND THUS WILL KEEP WINDS LESS THAN OR
EQUAL TO 15 KT. THE WIND DIRECTION FORECAST HAS AN INCREASED BUST
POTENTIAL DUE TO EACH OF THE MODELS OWN PARTICULAR SOLUTION WITH
REGARD TO THE POSITIONING OF THE COLD FRONT DURING THE NEXT 24
HRS. AT THIS POINT...WILL KEEP THE SFC COLD FRONT INLAND THIS
PERIOD ALLOWING WIND DIRECTIONS TO KEEP A SOUTHERLY TRAJECTORY TO
THE WIND FIELD. SIGNIFICANT SEAS WILL RUN 2 TO OCCASIONALLY 3 FT.
A 1-2 FOOT EASTERLY PSEUDO GROUND SWELL AT 8 SECOND PERIODS WILL
MOSTLY DOMINATE SIG. SEAS...WITH THE OTHER PORTION COMING FROM THE
LOCALLY PRODUCED 3 TO 5 SECOND PERIOD WIND DRIVEN WAVES.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...A LIGHT SOUTHERLY FLOW AHEAD OF COLD FRONT
WILL SHIFT AROUND TO NORTHEAST AS SHORTWAVE PUSHES COLD FRONT SOUTH OF
THROUGH LATE SATURDAY INTO SUNDAY. OVERALL EXPECT RATHER BENIGN
SEAS OF LESS THAN 3 FT OVER THE WEEKEND AS WINDS REMAIN 10 KTS OR
LESS AND MAY FLUCTUATE DEPENDING ON HOW FAR SOUTH THE FRONT MAKES
IT BEFORE STALLING OUT. CLOUD COVER AND PCP WILL HAMPER SURFACE
HEATING OVER THE LAND AND THEREFORE WILL KEEP SEA BREEZE WEAKER.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 330 AM FRIDAY...WINDS WILL REMAIN VERY LIGHT AND SOMEWHAT
VARIABLE AS LINGERING COLD FRONT WASHES OUT OVER THE WATERS
THROUGH EARLY NEXT WEEK. SEAS GENERALLY LESS THAN 3 FT THROUGH MONDAY
INTO EARLY TUES...BUT WNA SHOWS A LONGER PERIOD UP TO 14 SECOND EASTERLY
SWELL MOVING IN BY LATE TUES...POSSIBLY FROM TROPICAL SYSTEM
MOVING OUT OVER THE DISTANT ATLANTIC WATERS. THIS SHOULD PRODUCE A
GRADUAL RISE IN SEAS UP FROM 2 TO 3 FT TO AROUND 4 FT IN OUTER
WATERS.
&&
.TIDES/COASTAL FLOODING...
AS OF 10 AM FRIDAY...LATEST MODEL GUIDANCE ONCE AGAIN PUSH THE
TIDE GAGE LOCATED IN THE LOWER CAPE FEAR RIVER IN THE VICINITY OF
DOWNTOWN WILMINGTON...ABOVE THE 5.5 FT MLLW THRESHOLD FOR
SHALLOW/MINOR COASTAL FLOODING. IN FACT...MODELS TAKE IT TO JUST
6.00 FT MLLW AROUND 1 PM THIS AFTERNOON. OVERALL...BETWEEN THE
HOURS OF NOON AND 3 PM TODAY...MODEL GUIDANCE SUGGESTS GREATER
THAN OR EQUAL TO 5.5 FT MLLW TO OCCUR. AS A RESULT...A CFW HAS
BEEN ISSUED FOR BOTH INLAND AND COASTAL NEW HANOVER. COASTAL NEW
HANOVER IS INCLUDED...PARTICULAR FOR ROADWAYS SOUTH OF SNOWS CUT
BRIDGE BORDERING THE LOWER CAPE FEAR RIVER. AND...ACROSS CANAL
DRIVE OF CAROLINA BEACH.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...COASTAL FLOOD ADVISORY UNTIL 3 PM EDT THIS AFTERNOON FOR
NCZ107-108.
MARINE...NONE.
&&
$$
SYNOPSIS...MJC
NEAR TERM...DCH/MJC
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...DL
TIDES/COASTAL FLOODING...DCH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
952 PM CDT SAT SEP 13 2014
.UPDATE...
ISSUED AT 951 PM CDT SAT SEP 13 2014
NO SIGNIFICANT CHANGES REQUIRED WITH THIS UPDATE. DECIDED TO NOT
EXPAND THE FROST ADVISORY AS THE LOWEST DEW POINTS IN THE MID 30S
AS OF 0230 UTC RESIDE WITHIN THE CURRENT ADVISORY...WITH WINDS
EXPECTED TO BECOME CALM AS THE SURFACE RIDGE AXIS PROPAGATES INTO
WESTERN NORTH DAKOTA. ELSEWHERE OUTSIDE OF THE
ADVISORY...RELATIVELY GREATER LOW LEVEL MOISTURE...STRONGER WINDS
AND GREATER CLOUD COVER SHOULD KEEP TEMPERATURES WARM ENOUGH TO
PREVENT WIDESPREAD FROST.
UPDATE ISSUED AT 652 PM CDT SAT SEP 13 2014
NO CHANGES PLANNED AT THIS TIME IN REGARDS TO THE FROST ADVISORY
FOR TONIGHT...WHICH IS IN LINE WITH THE 18 UTC NAM/GFS/MAV. WILL
CONTINUE TO MONITOR CLOUD TRENDS THROUGH EVENING SHOULD A SMALL
EXPANSION OF THE ADVISORY BE NECESSARY.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 329 PM CDT SAT SEP 13 2014
COLD FRONT MOVING THROUGH THE REGION WILL GENERATE WIDELY
SCATTERED SHOWERS ACROSS NORTHERN NORTH DAKOTA THIS AFTERNOON AND
EARLY THIS EVENING. GENERALLY FOLLOWED THE HRRR IN AREA AND TIMING
OF THE SHOWERS. SHOWERS WILL END BEFORE MIDNIGHT. SKIES WILL CLEAR
WITH OVERNIGHT LOWS IN THE LOWER TO MIDDLE 30S WEST. ISSUED A
FROST ADVISORY ACROSS THE WEST...GENERALLY WEST OF THE MISSOURI
RIVER AND WEST OF MINOT. SURFACE HIGH PRESSURE WILL COVER THE
REGION SUNDAY AND ANOTHER ROUND OF PATCH FROST IS POSSIBLE SUNDAY
NIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 329 PM CDT SAT SEP 13 2014
THE EXTENDED PERIOD WILL REMAIN LARGELY DRY THROUGH THURSDAY AS A
LARGE UPPER LOW ACROSS EASTERN CANADA SLOWLY MOVES EAST. AS THIS
HAPPENS BROAD RIDGING WILL DEVELOP OVER THE CENTRAL AND NORTHERN
PLAINS. THIS WILL ALLOW A SLOW WARMING TREND THROUGH THE MIDDLE TO
AND OF NEXT WEEK. BY NEXT WEEKEND A COLD FRONT WILL MOVE THROUGH
BRINGING SCATTERED THUNDERSTORMS TO THE REGION THURSDAY NIGHT INTO
FRIDAY NIGHT.
FOR TEMPERATURES...SUNDAY NIGHT COULD SEE SOME SCATTERED FROST
BEFORE THE WARM UP BEGINS. OTHER THAN THAT...MORNING LOWS WILL B IN
THE 40S TO MIDDLE 50S WITH HIGHS IN THE 60S MONDAY AND THE 70S TO
AROUND 80 TUESDAY THROUGH SATURDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 941 PM CDT SAT SEP 13 2014
MVFR STRATUS WILL IMPACT KMOT THIS EVENING AND INTO THE EARLY
OVERNIGHT...POSSIBLY APPROACHING KJMS LATER TONIGHT. OTHERWISE...VFR
CONDITIONS ARE FORECAST FOR THE REMAINING TERMINALS FOR THE 00 UTC
TAF CYCLE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 3 AM CDT /2 AM MDT/ TO 9 AM CDT /8 AM MDT/
SUNDAY FOR NDZ001-002-009-010-017>021-031>034-040>045.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...WAA
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
652 PM CDT SAT SEP 13 2014
.UPDATE...
ISSUED AT 652 PM CDT SAT SEP 13 2014
NO CHANGES PLANNED AT THIS TIME IN REGARDS TO THE FROST ADVISORY
FOR TONIGHT...WHICH IS IN LINE WITH THE 18 UTC NAM/GFS/MAV. WILL
CONTINUE TO MONITOR CLOUD TRENDS THROUGH EVENING SHOULD A SMALL
EXPANSION OF THE ADVISORY BE NECESSARY.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 329 PM CDT SAT SEP 13 2014
COLD FRONT MOVING THROUGH THE REGION WILL GENERATE WIDELY
SCATTERED SHOWERS ACROSS NORTHERN NORTH DAKOTA THIS AFTERNOON AND
EARLY THIS EVENING. GENERALLY FOLLOWED THE HRRR IN AREA AND TIMING
OF THE SHOWERS. SHOWERS WILL END BEFORE MIDNIGHT. SKIES WILL CLEAR
WITH OVERNIGHT LOWS IN THE LOWER TO MIDDLE 30S WEST. ISSUED A
FROST ADVISORY ACROSS THE WEST...GENERALLY WEST OF THE MISSOURI
RIVER AND WEST OF MINOT. SURFACE HIGH PRESSURE WILL COVER THE
REGION SUNDAY AND ANOTHER ROUND OF PATCH FROST IS POSSIBLE SUNDAY
NIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 329 PM CDT SAT SEP 13 2014
THE EXTENDED PERIOD WILL REMAIN LARGELY DRY THROUGH THURSDAY AS A
LARGE UPPER LOW ACROSS EASTERN CANADA SLOWLY MOVES EAST. AS THIS
HAPPENS BROAD RIDGING WILL DEVELOP OVER THE CENTRAL AND NORTHERN
PLAINS. THIS WILL ALLOW A SLOW WARMING TREND THROUGH THE MIDDLE TO
AND OF NEXT WEEK. BY NEXT WEEKEND A COLD FRONT WILL MOVE THROUGH
BRINGING SCATTERED THUNDERSTORMS TO THE REGION THURSDAY NIGHT INTO
FRIDAY NIGHT.
FOR TEMPERATURES...SUNDAY NIGHT COULD SEE SOME SCATTERED FROST
BEFORE THE WARM UP BEGINS. OTHER THAN THAT...MORNING LOWS WILL B IN
THE 40S TO MIDDLE 50S WITH HIGHS IN THE 60S MONDAY AND THE 70S TO
AROUND 80 TUESDAY THROUGH SATURDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 651 PM CDT SAT SEP 13 2014
COLD FRONT PROGRESSING THROUGH THE REGION. WHILE VFR CONDITIONS
ARE FORECAST THROUGH THE PERIOD...CLOUDS AS LOW AS 3 THOUSAND AGL
ARE POSSIBLE AT KISN-KMOT AS THE COOLER AIR MOVES IN TONIGHT.
SCATTERED SHOWERS EXPECTED ACROSS THE NORTH UNTIL 03Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 3 AM CDT /2 AM MDT/ TO 9 AM CDT /8 AM MDT/
SUNDAY FOR NDZ001-002-009-010-017>021-031>034-040>045.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...WAA
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS TULSA OK
1152 PM CDT THU SEP 11 2014
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
MVFR CEILINGS ARE EXPECTED TO REMAIN ACROSS THE REGION THROUGH THE
MAJORITY OF THE TAF PERIOD. PERIODS OF IFR CONDITIONS LOOK TO BE
POSSIBLE LATE TONIGHT/EARLY FRIDAY MORNING OVER SOUTHEAST
OKLAHOMA AND NORTHWEST ARKANSAS AS CHANCES FOR SHOWERS AND
THUNDERSTORMS SPREAD NORTHWARD. SOME AREAS OF LIGHT DRIZZLE/RAIN
COULD ALSO BE POSSIBLE OVER PARTS OF NORTHEAST OKLAHOMA WHICH
COULD CREATE AREAS OF IFR CEILINGS. GREATER PRECIP CHANCES LOOK
TO BE MAINLY OVER SOUTHEAST OKLAHOMA INTO WEST CENTRAL ARKANSAS
INTO THE AFTERNOON HOURS.
&&
.PREV DISCUSSION... /ISSUED 929 PM CDT THU SEP 11 2014/
DISCUSSION...
REGIONAL SFC ANALYSIS SHOWS FRONTAL BOUNDARY STALLED NEAR/SOUTH OF
I-20 IN TEXAS WITH A SECOND...STRONGER SURGE OF COLD AIR SLIDING
DOWN THE FRONT RANGE OF THE ROCKIES. THUS FAR NO PRECIP IN THE
AREA BUT LATER TONIGHT IN RESPONSE TO MID LEVEL WAVE DIVING
THROUGH CENTRAL ROCKIES...EXPECT LIFT TO INCREASE NORTH OF THE
STALLED BOUNDARY RESULTING IN INCREASING COVERAGE OF SHOWERS
MAINLY ALONG AND SOUTH OF I-40 TOWARD MORNING. BOTH HRRR AND LOCAL
WRF HAVE REMAINED CONSISTENT IN DEPICTING THIS SCENARIO WITH
ELEVATED INSTABILITY ALSO INCREASING. THUS WILL KEEP THE HIGHER
CHANCES OF SHOWERS LATE TONIGHT IN SOUTHERN AREAS...ONLY REAL
CHANGE TO FORECAST WAS TO TAKE OUT MOST PRECIP THROUGH 06Z. TEMPS
FALLING SLOWLY UNDER LOW CLOUD DECK WHICH WILL HOLD FIRM...HOWEVER
SECOND SURGE OF COLDER AIR LIKELY WILL DROP AREAS NEAR KS BORDER
INTO THE 50S BY MORNING. NO ADDITIONAL UPDATES AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 60 68 51 72 / 20 50 20 10
FSM 65 71 57 74 / 50 50 30 10
MLC 65 69 55 72 / 50 60 30 10
BVO 56 66 46 70 / 10 50 20 0
FYV 58 66 50 69 / 20 40 30 10
BYV 57 67 50 68 / 20 40 30 10
MKO 62 67 52 71 / 30 50 30 10
MIO 56 67 47 69 / 10 30 20 0
F10 61 68 52 71 / 30 50 30 10
HHW 68 73 60 75 / 70 70 40 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...20
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1115 PM CDT THU SEP 11 2014
.AVIATION...
MVFR CIGS ARE FILTERING SOUTH INTO METROPLEX NOW...AND GFS/NAM
MOS SHOW IFR NEAR SUNRISE. THIS IS LIKELY DUE TO COLUMN
SATURATION AS THE WARM ADVECTION SHRA/TSRA DEVELOP IN THE EARLY
MORNING. HAVE PRETTY MUCH CONTINUED WITH PREVIOUS TAF/S OVERNIGHT
PRECIP SCENARIO. RAIN STILL APPEARS TO BE MORE LIKELY NORTH OF
THE METROPLEX AND HAVE CONTINUED THE SHRA WITH VCTS RATHER THAN
HITTING PRECIP HARDER.
THE STRONG COLD ADVECTION DURING THE DAY FRIDAY WILL KEEP
CEILINGS FROM LIFTING ABOVE 020 AND HAVE LOWERED CEILINGS NOW FOR
THE ENTIRE DAY. NORTH WINDS WILL PICK UP IN THE MORNING REACHING
THE HIGH TEENS WITH GUSTS INTO THE MID 20S.
COLD ADVECTION WILL ALSO AFFECT WACO...HOLDING IN LOWER CEILINGS.
I DO NOT EXPECT AFTERNOON STORMS THERE (THEY SHOULD BE FARTHER
SOUTH) DUE TO THE STABILIZING EFFECTS OF THE COLD ADVECTION. 84
&&
.UPDATE...
A POTENT UPPER TROUGH IS NOW SWINGING INTO THE NORTHERN PLAINS
AND AN UNSEASONABLY COLD AIR MASS HAS INVADED MUCH OF THE GREAT
PLAINS REGION. TEMPERATURES IN THE 40S EXTEND AS FAR SOUTH AS NW
KANSAS WITH READINGS IN THE 30S FARTHER NORTHWEST NEAR THE CORE OF
A 1035 MB HIGH PRESSURE CELL. AGAIN THIS IS UNUSUALLY COLD FOR
THIS TIME OF DAY IN EARLY TO MID SEPTEMBER. THE SURFACE HIGH WILL
CONTINUE TO DROP SOUTHEAST AND SEND A REINFORCING SURGE OF COLD
AIR SOUTH IN THE REGION BY MORNING. NORTH WINDS WILL INCREASE
DURING THE DAY...LIKELY INTO THE 15 TO 20 MPH RANGE BY MID-LATE
AFTERNOON. FORECASTED HIGH TEMPS FOR TOMORROW LOOK GOOD...BUT DUE
TO THE STRONG COLD ADVECTION...DID UPDATE TO SHOW FALLING
TEMPERATURES DURING THE AFTERNOON HOURS BEHIND THE FRONT. IT
CERTAINLY WILL FEEL FALL-LIKE TOMORROW. ALSO LOWERED LOW TEMPS
FRIDAY NIGHT A FEW DEGREES ACROSS THE WESTERN AND CENTRAL ZONES IN
ACCORDANCE WITH THE WRF FORECASTS...WHICH ARE USUALLY SUPERIOR
WITH TEMPS IN THIS PATTERN.
AS FAR AS RAIN CHANCES GO...WE ARE IN A LULL THIS EVENING AS
EXPECTED...BUT ALL GUIDANCE CONTINUES TO ADVERTISE AN INCREASE IN
ISENTROPIC ASCENT NEAR 700-850MB WHERE PARCELS ARE CONVECTIVELY
UNSTABLE. MOST OF THIS ELEVATED CONVECTION WILL FORM PRIMARILY
NORTHEAST OF A BOWIE TO DFW TO CORSICANA LINE AFTER MIDNIGHT
WHERE THE ISENTROPIC LIFT...MOISTURE AND INSTABILITY ALL ALIGN
BEST. WHEN THE REINFORCING COLD FRONT ARRIVES AFTER
SUNRISE...FRONTOGENETIC FORCING WILL RAMP UP AND AID IN ADDITIONAL
LIFT WITH A BAND OF RAIN/STORMS FORMING ROUGHLY ALONG A COMANCHE
TO DFW TO PARIS LINE BY MID MORNING. THIS ACTIVITY WILL GRADUALLY
WORK/DEVELOP SOUTHEASTWARD DURING THE DAY...BUT LIKELY WILL NOT
MAINTAIN A SOLID/CONTINUOUS LINE AS IT DOES SO. ALL IN ALL NO
CHANGE TO THE PRECIP FORECAST WAS REQUIRED.
TR.92
&&
.PREV DISCUSSION... /ISSUED 321 PM CDT THU SEP 11 2014/
PLENTY OF CHALLENGES THIS FORECAST PACKAGE AS WE TRACK A SLOW-
MOVING FRONT NOW EXTENDING FROM A GATESVILLE...TO CORSICANA...TO
CANTON LINE. A BROKEN LINE OF SHOWERS AND THUNDERSTORMS CONTAINING
LOCALLY HEAVY RAINFALL HAS ERUPTED IN THE PAST 1-2 HOURS ALONG THE
BOUNDARY. IN ADDITION...LOCALIZED FLOODING ISSUES WILL NEED TO BE
MONITORED ALONG THE COLD FRONT WITH THIS BROKEN LINE OF STORMS
WITH RICH PRECIPITABLE WATER VALUES WELL ABOVE 2 INCHES AND HIGH
THETA-E AIR BETWEEN 700-850MB. ANY TRAINING ACTIVITY WILL LIKELY
CAUSE SOME LOCALIZED HYDROLOGIC PROBLEMS. WE WILL CARRY THE HIGHEST
RAIN CHANCES THIS EVENING ALONG AND AHEAD OF THE FRONT OR ACROSS
THE SOUTHEAST HALF OF THE REGION. THE BEST INSTABILITY AND FORCING
WITH THE COLD FRONT WILL MOST LIKELY DRIVE THIS ACTIVITY THROUGH
NIGHTFALL. IN ADDITION...WE HAVE ADDED HIGHER CHANCES ACROSS THE
FAR WESTERN COUNTIES FOR LATE EVENING. THE APPROACH OF A SUBTLE
DISTURBANCE OVER WEST TEXAS WILL LIKELY PROVIDE ENOUGH LIFT TO
SUSTAIN A FEW SHOWER OR STORMS ACROSS THE FAR WESTERN COUNTIES
AFTER SUNSET.
THE WEST TEXAS DISTURBANCE WILL CONTINUE TO MOVE OVER THE RED RIVER
AREA AND SOUTHERN OKLAHOMA TONIGHT. NORTHERN AREAS...ESPECIALLY
THOSE ALONG AND NORTH OF I-20 WILL BE UNDERNEATH THE RIGHT ENTRANCE
REGION OF A 60-70KT JET STREAK STREAMING OVER OKLAHOMA. AS WE HEAD
INTO FRIDAY MORNING...A STRONGER DISTURBANCE CURRENTLY OVER WYOMING
WILL ROTATE SOUTHEAST OVER THE KANSAS/NEBRASKA BORDER AND SHOULD
SHUNT THE JET STREAK A LITTLE FURTHER SOUTH. THE COMBINATION OF
THESE FEATURES WILL PROVIDE THE SYNOPTIC LIFT...WHILE NOCTURNAL
LOW LEVEL WARM ADVECTION OVERRIDES THE SHALLOW FRONTAL INVERSION.
WITH THE FOCUS SHIFTING BACK NORTH...WILL MAINTAIN LIKELY CHANCES
FOR RAINFALL WHICH AT TIMES COULD BE LOCALLY HEAVY...BUT NOT ENOUGH
ALONG WITH ANTECEDENT DRY SOIL CONDITIONS TO ISSUE ANY FLOOD WATCHES
AT THIS POINT. 500-700MB LAPSE RATES WILL BE HOVERING AROUND 6 DEG/KM
WITH BOTH RUC AND NAM12 BUFKIT SOUNDINGS INDICATING A DEEP...BUT
SKINNY LAYER OF CAPE. ALL TOLD...SHOWERS WILL BE LIKELY OVERNIGHT
TONIGHT INTO FRIDAY MORNING ACROSS THESE AREAS WITH EMBEDDED/ELEVATED
THUNDERSTORMS AT TIMES. RAIN CHANCES AFTER NIGHTFALL ACROSS CENTRAL
TEXAS SHOULD DIMINISH TO LOWER CHANCES THAN WHAT WILL BE SEEN
ACROSS THE NORTH. THERE WILL BE QUITE A VARIANCE ON HIGH TEMPERATURES
FROM NORTHWEST TO SOUTHEAST FRIDAY. HIGHS WILL ONLY PUSH TO AROUND
70 DEGREES ACROSS THE FAR NORTHWEST... TO THE LOWER 90S ACROSS THE
FAR SOUTHEAST.
BETTER RAIN CHANCES SHIFT BACK OVER CENTRAL TEXAS ONCE AGAIN
FRIDAY AFTERNOON INTO SATURDAY MORNING. THE PASSAGE OF THE STRONG
SHORTWAVE TO THE NORTH TOWARD NORTHERN MISSOURI AND IOWA WILL HELP
SEND A STRONGER AND DEEPER PUSH OF COOLER AIR INTO THE NORTHERN
COUNTIES WITH THE SOUTH REMAINING WARMER AND MORE UNSTABLE. THE
UPPER HIGH WILL STRENGTHEN SOME BACK OVER THE AREA THIS WEEKEND
WITH JUST LINGERING LOW RAIN CHANCES ACROSS CENTRAL TEXAS WHERE
DEEPER MOISTURE WILL LINGER. THESE CHANCES SHOULD END BY NIGHTFALL
SATURDAY EVENING AS THE ATMOSPHERE STABILIZES. EVEN SO...CLOUD
COVER ON AND ABOVE THE DEEPENING FRONTAL INVERSION WILL MAINTAIN
CONSIDERABLE CLOUDINESS ACROSS THE REGION. THE CLOUDS COMBINED
WITH THE COOLER AIRMASS WILL HOLD HIGHS BETWEEN 75 AND 85 DEGREES
SATURDAY THAT WILL SLOWLY MODIFY TO THE 80S ON SUNDAY.
THE FORECAST AFTER THE WEEKEND BECOMES CHALLENGING ONCE AGAIN AS
WE MONITOR AN UPPER DISTURBANCE ROTATING AROUND THE WESTERN PERIPHERY
OF THE UPPER HIGH OVER THE WESTERN GULF COAST ON MONDAY. BY MONDAY
NIGHT AND TUESDAY...ANOTHER STRONG DISTURBANCE WILL MOVE DOWN
WITHIN NORTHWEST FLOW ALOFT ACROSS THE CENTRAL PLAINS AND DRAG A
SECOND COLD FRONT INTO SOUTHERN PLAINS BY TUESDAY. MOISTURE WILL
BE PLENTIFUL ENOUGH THAT WE HAVE MAINTAINED THE LOW CHANCES FOR
SHOWERS AND STORMS UNTIL TIMING AND ENVIRONMENTAL DETAILS BECOME
CLEARER FOR THAT TIME FRAME AND WE CAN DIAGNOSE WHEN THE BEST
CHANCES WILL OCCUR. THE LATTER HALF OF NEXT WEEK WAS KEPT DRY AND
WARM FOR NOW...AS THE SECOND FRONT WASHES OUT OVER THE SOUTHERN
PART OF THE STATE. HOWEVER...LOW RAIN CHANCES MAY NEED TO BE
EXTENDED ACROSS OUR CENTRAL TEXAS COUNTIES IF THE FRONT STALLS
FURTHER NORTH. HIGH TEMPERATURES WILL MODIFY BACK TO THE MID AND
UPPER 80S WITH A FEW READINGS IN THE LOWER 90S POSSIBLE ACROSS OUR
CENTRAL TEXAS COUNTIES.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 73 75 60 77 66 / 70 70 20 10 10
WACO, TX 73 84 63 79 65 / 40 50 40 30 10
PARIS, TX 71 72 59 75 62 / 70 70 20 10 10
DENTON, TX 70 72 58 77 64 / 70 70 20 10 10
MCKINNEY, TX 70 73 58 75 63 / 70 70 20 10 10
DALLAS, TX 73 76 60 76 67 / 60 70 20 10 10
TERRELL, TX 73 79 61 76 64 / 60 70 30 10 10
CORSICANA, TX 74 83 63 79 65 / 40 50 40 20 10
TEMPLE, TX 72 88 63 78 65 / 20 60 50 30 20
MINERAL WELLS, TX 69 72 57 75 63 / 70 70 20 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
129 PM EDT FRI SEP 12 2014
.SYNOPSIS...
A COLD FRONT EXTENDS FROM THE MID ATLANTIC COAST...WEST THROUGH
THE LOWER TENNESSEE VALLEY AND INTO EAST TEXAS. THIS FRONT WILL
DRIFT A LITTLE FARTHER SOUTH TODAY...BECOMING NEARLY STATIONARY
JUST SOUTH OF OUR REGION. A WAVE OF LOW PRESSURE WILL RIPPLE EAST
ALONG THE FRONT TONIGHT AND SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1225 PM EDT FRIDAY...
WEDGE HAS ADVANCED THROUGH THE EASTERN COUNTY WARNING AREA WITH
LOWER DEW POINTS AND MORE STABLE AIR AS SEEN ON THE MSAS LIFTED
INDEX ANALYSIS AT 16Z/NOON. MOST LIKELY LOCATION FOR SCATTERED
THUNDERSTORMS THIS AFTERNOON REMAIN IN THE NORTH CAROLINA
MOUNTAINS AND FOOTHILLS WERE THERE HAS BEEN SOME HEATING AND CAPES
WERE UP CLOSE TO 900 J/KG. LOCAL WRF AND HRRR RUNS HAVE STORMS
DEVELOPING BETWEEN 17Z/1PM AND 19Z/3PM. MODELS ALSO BRING LOW
LEVEL WINDS AROUND TO THE NORTHEAST THEN EAST BY 20Z/4PM WHICH
WILL ALSO INCREASE THE CONVERGENCE ALONG THE SOUTHERN BLUE RIDGE
DURING THIS TIME FRAME.
HAVE ADJUSTED THE MAXIMUM TEMPERATURES A COUPLE OF DEGREES DOWN IN
THE NORTHEAST UNDER THE WEDGE...AND A FEW DEGREES WARMER IN THE
SOUTHWEST WHERE THERE HAS BEEN MORE SUN.
BY TONIGHT ALL AREAS WILL BE UNDER THE GUN FOR NUMEROUS
SHOWERS...AND OR A MUCH LARGER SCALE RAIN EVENT. MODELS ARE IN
AGREEMENT THAT A WAVE OF LOW PRESSURE WILL RIPPLE EAST ALONG THE
FRONT TONIGHT...WIDESPREAD RAIN/DRIZZLE DEVELOPING OVER THE
AREA...CONTINUING SATURDAY. THERE IS A VERY DISTINCT UPPER LEVEL
TROUGH THAT WILL BE MOVING OUT OF THE CENTRAL PLAINS
TODAY...CROSSING THE OHIO VALLEY TONIGHT. STRONG DYNAMIC LIFT
ASSOCIATED WITH THIS FEATURE WILL RESULT IN A BAND OF RAIN THAT
WILL MOVE EAST ACROSS THE OHIO VALLEY...APPROACHING OUR AREA FROM
THE WEST. MORE IMPORTANTLY...BACKING FLOW AHEAD OF THIS TROF WILL
CAUSE LOW LEVEL WINDS OVER THE MID ATLANTIC REGION TO BECOME
SOUTHEASTERLY. THIS SOUTHEAST WIND WILL THEN MOVE UPSLOPE INTO THE
BLUE RIDGE...THIS INCREASING OROGRAPHIC LIFT RESULTING IN
RAIN/DRIZZLE/FOG.
GENERAL RAINFALL ACROSS THE CWA THROUGH TONIGHT IS EXPECTED TO
BE AROUND A QUARTER OF AN INCH. HOWEVER...AN ENHANCED AREA OF
RAINFALL IS LIKELY TO OCCUR OVER THE NORTH CAROLINA MOUNTAINS
WHERE UPWARDS OF AN INCH OF RAIN MAY OCCUR. A SIMILAR SITUATION
OCCURRED LAST WEEKEND WHEN THE NC HIGH COUNTRY ENDED UP WITH 1-3
INCHES OF RAIN...THE FRONT AT THAT TIME LAGGING. THE NET RESULT
WAS WARMER TEMPERATURES DURING THE DAY PRIOR TO THE RAINFALL (6
DEG ABOVE GUIDANCE) AND CAPES OF ABOUT 1000 J/KG. BUFKIT SOUNDING
AT BOONE TODAY IS SUGGESTING THE CAPE WILL REACH 750 J/KG. COMBINE
THIS WITH A PWAT THAT IS CLOSE TO 200% ABOVE NORMAL AND THE NET
EFFECT MAY BE THE SAME AS LAST SUNDAYS HIGH COUNTRY DELUGE.
CLOUDS WILL EVENTUALLY FILL BACK IN PER THE APPROACHING UPPER
LEVEL TROUGH AND BACKING LOW LEVEL FLOW. TEMPERATURES TONIGHT
SHOULD LEVEL OFF CLOSE TO THE DEWPOINT VALUES...THE RAIN COOLED
AIR RESULTING IN TMINS IN THE U50S/L60S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 430 AM EDT FRIDAY...
BY SATURDAY MORNING...AN UPPER LEVEL TROUGH WILL PASS RAPIDLY
EASTWARD ACROSS THE GREAT LAKES...WHILE UPPER LEVEL RIDGING WILL
REMAIN STEADFAST ACROSS THE SOUTHEAST. DEEPENING SURFACE LOW
PRESSURE ASSOCIATED WITH THE UPPER TROUGH WILL BE RACING NORTHEAST
OF OUR AREA INTO QUEBEC...DRAGGING A COLD FRONT TOWARD THE
APPALACHIAN CHAIN.
WITH WINDS HAVING SHIFTED SOUTHWESTERLY AHEAD OF THE APPROACHING
COLD FRONT...ATLANTIC MOISTURE WILL POOL ACROSS OUR AREA...PUSHING
PRECIPITABLE WATER VALUES INTO THE 1.6 TO 1.9 INCH RANGE.
INSTABILITY ASSOCIATED WITH THE UPPER TROUGH...COMBINED WITH LOW
LEVEL CONVERGENCE AHEAD OF THE FRONT...WILL SUPPORT RAIN FOR MUCH OF
OUR AREA...SOME OF WHICH WILL BE LOCALLY HEAVY. BELIEVE RAINFALL
WILL BE ON AND OFF BUT NEARLY EVERYWHERE WILL OBSERVE MEASURABLE
RAINFALL AT SOME POINT DURING THE MORNING. THE COLD FRONT WILL ENTER
OUR SOUTHEAST WEST VIRGINIA COUNTIES BY LATE MORNING...WITH DRIER
COOLER CANADIAN AIR BUILDING FROM BEHIND. AS SUCH...EXPECT
DECREASING RAIN CHANCES FROM NORTHWEST TO SOUTHEAST DURING THE
AFTERNOON AS THE FRONT PASSES THROUGH. EXPECT ONLY SPOTTY SHOWERS
REMAINING ACROSS THE PIEDMONT DURING EARLY EVENING...AS WELL AS IN
THE NORTHWEST WIND UPSLOPE AREAS ACROSS THE MOUNTAINS. THE FRONT
WILL BEGIN TO STALL ACROSS THE CAROLINAS SATURDAY NIGHT AS UPPER
RIDGING ACROSS THE AREA HALTS ITS SOUTHWARD ADVANCE.
HIGH PRESSURE WILL SHIFT ACROSS THE GREAT LAKES SATURDAY NIGHT INTO
NEW ENGLAND...WHERE IT WILL THEN BUILD SOUTHWARD...HUGGING THE
EASTERN FACE OF THE APPALACHIANS. NORTHEAST WINDS FLOWING AROUND THE
HIGH WILL DRAW COOL MARITIME AIR INTO OUR AREA...FORCING IT UP THE
BLUE RIDGE. AS SUCH...EXPECT MOSTLY CLOUDY SKIES WITH AREAS OF
DRIZZLE OR LIGHT RAIN AND PATCHES OF FOG IN THE MOUNTAINS. HAVE
UNDERCUT MAV/MET GUIDANCE FOR AFTERNOON TEMPERATURES ON SUNDAY...
HOLDING MOST LOCATIONS IN THE 60S FOR HIGHS. THE EXCEPTION MAY BE IN
PORTIONS OF THE MOUNTAIN EMPIRE ON THE WESTERN SIDE OF THE HIGHER
RIDGELINES...WHICH MAY WARM INTO THE MID 70S IF THE SUN BREAKS OUT
OF THE CLOUDS.
ON MONDAY...HIGH PRESSURE WILL MOVE OFFSHORE...ALLOWING WINDS TO
GRADUALLY SHIFT MORE SOUTHERLY AS ANOTHER COLD FRONT APPROACHES FROM
THE WEST. AS SUCH...EXPECT WARMER TEMPERATURES...WITH AFTERNOON
HIGHS CLIMBING INTO THE LOW TO MID 70S. RAIN CHANCES WILL INCREASE
DURING THE EVENING...WITH THE COLD FRONT ENTERING THE AREA MONDAY
NIGHT.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 330 AM EDT FRIDAY...
UNSETTLED WEATHER CONTINUES TUESDAY AS SEVERAL UPPER LEVEL
DISTURBANCES WILL SHIFT EAST ACROSS OUR AREA. SOME DRIER AIR WILL
TRY TO PUSH ACROSS THE REGION TUESDAY NIGHT INTO WEDNESDAY.
HOWEVER...SOME ISOLATED CONVECTION MAY FORM ACROSS THE SOUTHWESTERN
HIGH TERRAIN CLOSER TO THE FRONTAL BOUNDARY WITH BETTER INSTABILITY.
WEDNESDAY NIGHT INTO FRIDAY...THE HIGH CENTER OVER NEW ENGLAND WILL
SLOWLY MOVE EAST TOWARDS THE ATLANTIC OCEAN.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 100 PM EDT FRIDAY...
GOOD CONFIDENCE IN POOR AVIATION CONDITIONS FOR TAF SITES THROUGH
THIS FORECAST PERIOD. FRONTAL BOUNDARY WHICH PUSHED THROUGH THE
REGION YESTERDAY HAS STALLED OVER THE AREA...AND ENERGY ALOFT WILL
HELP WAVES OF LOW PRESSURE TO RIPPLE ALONG THE FRONT. THIS WILL KEEP
A MOIST ELY FLOW RUNNING UP INTO THE BLUE RIDGE THROUGH SATURDAY.
MULTILAYER CLOUDS WILL MAKE IT HARD TO PIN DOWN CIGS...BUT EXPECT THE
OVERALL FLAVOR OF AVIATION CONDITIONS TO LEAN TOWARD MVFR/VFR VERY
EARLY IN THE PERIOD...THOUGH LOWER CONDITIONS WILL BRIEFLY PREVAIL
AS PATCHY AREAS OF LIGHT RAIN/DRIZZLE AFFECT INDIVIDUAL SITES...THEN
A RAPID DESCENT TO LIFR/IFR TONIGHT. BELIEVE THE BIGGEST ISSUE WILL BE
LOW CIGS THROUGH KLWB WILL LIKELY BE SOCKED IN WITH LOW VSBY AS WELL.
THERE LOOKS TO BE SOME IMPROVEMENT IN CONDITIONS LATE IN THE PERIOD AS
THE ENERGY BEGINS TO PULL AWAY AND HIGH PRESSURE OVER THE UPPER MIDWEST
NUDGES THE FRONT A BIT FURTHER SOUTH.
EXTENDED AVIATION DISCUSSION...
NOT EXPECTING MUCH IF ANY IMPROVEMENT THROUGH THE WEEKEND...EVEN
AFTER THE -RA ENDS SUNDAY...LOW LEVEL CLOUDINESS WILL REMAIN.
BEYOND SUNDAY...HIGH AMPLITUDE SYSTEMS WILL RIDE BY TO OUR NORTH IN
QUASI ZONAL FLOW. THIS WILL KEEP US ON THE EDGE OF WEATHER SYSTEMS
THROUGH THE EXTENDED PERIOD. MODELS SHOWING OVERALL MVFR TO
PERSIST INTO MONDAY BEFORE SOUTHWEST WINDS ALOFT BEGIN TO RESULT
IN IMPROVING CONDITIONS. EVEN THOUGH LOW CLOUDS ERODE ON
MONDAY...LINGERING MOISTURE EXPECTING POTENTIAL FOR MVFR AT TIMES
IN SPOTTY SHOWERS MONDAY AFTERNOON AS ANOTHER UPPER TROUGH
APPROACHES THE REGION FROM THE WEST.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PM
NEAR TERM...AMS/PM
SHORT TERM...NF
LONG TERM...NF
AVIATION...MBS/PM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1232 PM EDT FRI SEP 12 2014
.SYNOPSIS...
A COLD FRONT EXTENDS FROM THE MID ATLANTIC COAST...WEST THROUGH
THE LOWER TENNESSEE VALLEY AND INTO EAST TEXAS. THIS FRONT WILL
DRIFT A LITTLE FARTHER SOUTH TODAY...BECOMING NEARLY STATIONARY
JUST SOUTH OF OUR REGION. A WAVE OF LOW PRESSURE WILL RIPPLE EAST
ALONG THE FRONT TONIGHT AND SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1225 PM EDT FRIDAY...
WEDGE HAS ADVANCED THROUGH THE EASTERN COUNTY WARNING AREA WITH
LOWER DEW POINTS AND MORE STABLE AIR AS SEEN ON THE MSAS LIFTED
INDEX ANALYSIS AT 16Z/NOON. MOST LIKELY LOCATION FOR SCATTERED
THUNDERSTORMS THIS AFTERNOON REMAIN IN THE NORTH CAROLINA
MOUNTAINS AND FOOTHILLS WERE THERE HAS BEEN SOME HEATING AND CAPES
WERE UP CLOSE TO 900 J/KG. LOCAL WRF AND HRRR RUNS HAVE STORMS
DEVELOPING BETWEEN 17Z/1PM AND 19Z/3PM. MODELS ALSO BRING LOW
LEVEL WINDS AROUND TO THE NORTHEAST THEN EAST BY 20Z/4PM WHICH
WILL ALSO INCREASE THE CONVERGENCE ALONG THE SOUTHERN BLUE RIDGE
DURING THIS TIME FRAME.
HAVE ADJUSTED THE MAXIMUM TEMPERATURES A COUPLE OF DEGREES DOWN IN
THE NORTHEAST UNDER THE WEDGE...AND A FEW DEGREES WARMER IN THE
SOUTHWEST WHERE THERE HAS BEEN MORE SUN.
BY TONIGHT ALL AREAS WILL BE UNDER THE GUN FOR NUMEROUS
SHOWERS...AND OR A MUCH LARGER SCALE RAIN EVENT. MODELS ARE IN
AGREEMENT THAT A WAVE OF LOW PRESSURE WILL RIPPLE EAST ALONG THE
FRONT TONIGHT...WIDESPREAD RAIN/DRIZZLE DEVELOPING OVER THE
AREA...CONTINUING SATURDAY. THERE IS A VERY DISTINCT UPPER LEVEL
TROUGH THAT WILL BE MOVING OUT OF THE CENTRAL PLAINS
TODAY...CROSSING THE OHIO VALLEY TONIGHT. STRONG DYNAMIC LIFT
ASSOCIATED WITH THIS FEATURE WILL RESULT IN A BAND OF RAIN THAT
WILL MOVE EAST ACROSS THE OHIO VALLEY...APPROACHING OUR AREA FROM
THE WEST. MORE IMPORTANTLY...BACKING FLOW AHEAD OF THIS TROF WILL
CAUSE LOW LEVEL WINDS OVER THE MID ATLANTIC REGION TO BECOME
SOUTHEASTERLY. THIS SOUTHEAST WIND WILL THEN MOVE UPSLOPE INTO THE
BLUE RIDGE...THIS INCREASING OROGRAPHIC LIFT RESULTING IN
RAIN/DRIZZLE/FOG.
GENERAL RAINFALL ACROSS THE CWA THROUGH TONIGHT IS EXPECTED TO
BE AROUND A QUARTER OF AN INCH. HOWEVER...AN ENHANCED AREA OF
RAINFALL IS LIKELY TO OCCUR OVER THE NORTH CAROLINA MOUNTAINS
WHERE UPWARDS OF AN INCH OF RAIN MAY OCCUR. A SIMILAR SITUATION
OCCURRED LAST WEEKEND WHEN THE NC HIGH COUNTRY ENDED UP WITH 1-3
INCHES OF RAIN...THE FRONT AT THAT TIME LAGGING. THE NET RESULT
WAS WARMER TEMPERATURES DURING THE DAY PRIOR TO THE RAINFALL (6
DEG ABOVE GUIDANCE) AND CAPES OF ABOUT 1000 J/KG. BUFKIT SOUNDING
AT BOONE TODAY IS SUGGESTING THE CAPE WILL REACH 750 J/KG. COMBINE
THIS WITH A PWAT THAT IS CLOSE TO 200% ABOVE NORMAL AND THE NET
EFFECT MAY BE THE SAME AS LAST SUNDAYS HIGH COUNTRY DELUGE.
CLOUDS WILL EVENTUALLY FILL BACK IN PER THE APPROACHING UPPER
LEVEL TROUGH AND BACKING LOW LEVEL FLOW. TEMPERATURES TONIGHT
SHOULD LEVEL OFF CLOSE TO THE DEWPOINT VALUES...THE RAIN COOLED
AIR RESULTING IN TMINS IN THE U50S/L60S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 430 AM EDT FRIDAY...
BY SATURDAY MORNING...AN UPPER LEVEL TROUGH WILL PASS RAPIDLY
EASTWARD ACROSS THE GREAT LAKES...WHILE UPPER LEVEL RIDGING WILL
REMAIN STEADFAST ACROSS THE SOUTHEAST. DEEPENING SURFACE LOW
PRESSURE ASSOCIATED WITH THE UPPER TROUGH WILL BE RACING NORTHEAST
OF OUR AREA INTO QUEBEC...DRAGGING A COLD FRONT TOWARD THE
APPALACHIAN CHAIN.
WITH WINDS HAVING SHIFTED SOUTHWESTERLY AHEAD OF THE APPROACHING
COLD FRONT...ATLANTIC MOISTURE WILL POOL ACROSS OUR AREA...PUSHING
PRECIPITABLE WATER VALUES INTO THE 1.6 TO 1.9 INCH RANGE.
INSTABILITY ASSOCIATED WITH THE UPPER TROUGH...COMBINED WITH LOW
LEVEL CONVERGENCE AHEAD OF THE FRONT...WILL SUPPORT RAIN FOR MUCH OF
OUR AREA...SOME OF WHICH WILL BE LOCALLY HEAVY. BELIEVE RAINFALL
WILL BE ON AND OFF BUT NEARLY EVERYWHERE WILL OBSERVE MEASURABLE
RAINFALL AT SOME POINT DURING THE MORNING. THE COLD FRONT WILL ENTER
OUR SOUTHEAST WEST VIRGINIA COUNTIES BY LATE MORNING...WITH DRIER
COOLER CANADIAN AIR BUILDING FROM BEHIND. AS SUCH...EXPECT
DECREASING RAIN CHANCES FROM NORTHWEST TO SOUTHEAST DURING THE
AFTERNOON AS THE FRONT PASSES THROUGH. EXPECT ONLY SPOTTY SHOWERS
REMAINING ACROSS THE PIEDMONT DURING EARLY EVENING...AS WELL AS IN
THE NORTHWEST WIND UPSLOPE AREAS ACROSS THE MOUNTAINS. THE FRONT
WILL BEGIN TO STALL ACROSS THE CAROLINAS SATURDAY NIGHT AS UPPER
RIDGING ACROSS THE AREA HALTS ITS SOUTHWARD ADVANCE.
HIGH PRESSURE WILL SHIFT ACROSS THE GREAT LAKES SATURDAY NIGHT INTO
NEW ENGLAND...WHERE IT WILL THEN BUILD SOUTHWARD...HUGGING THE
EASTERN FACE OF THE APPALACHIANS. NORTHEAST WINDS FLOWING AROUND THE
HIGH WILL DRAW COOL MARITIME AIR INTO OUR AREA...FORCING IT UP THE
BLUE RIDGE. AS SUCH...EXPECT MOSTLY CLOUDY SKIES WITH AREAS OF
DRIZZLE OR LIGHT RAIN AND PATCHES OF FOG IN THE MOUNTAINS. HAVE
UNDERCUT MAV/MET GUIDANCE FOR AFTERNOON TEMPERATURES ON SUNDAY...
HOLDING MOST LOCATIONS IN THE 60S FOR HIGHS. THE EXCEPTION MAY BE IN
PORTIONS OF THE MOUNTAIN EMPIRE ON THE WESTERN SIDE OF THE HIGHER
RIDGELINES...WHICH MAY WARM INTO THE MID 70S IF THE SUN BREAKS OUT
OF THE CLOUDS.
ON MONDAY...HIGH PRESSURE WILL MOVE OFFSHORE...ALLOWING WINDS TO
GRADUALLY SHIFT MORE SOUTHERLY AS ANOTHER COLD FRONT APPROACHES FROM
THE WEST. AS SUCH...EXPECT WARMER TEMPERATURES...WITH AFTERNOON
HIGHS CLIMBING INTO THE LOW TO MID 70S. RAIN CHANCES WILL INCREASE
DURING THE EVENING...WITH THE COLD FRONT ENTERING THE AREA MONDAY
NIGHT.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 330 AM EDT FRIDAY...
UNSETTLED WEATHER CONTINUES TUESDAY AS SEVERAL UPPER LEVEL
DISTURBANCES WILL SHIFT EAST ACROSS OUR AREA. SOME DRIER AIR WILL
TRY TO PUSH ACROSS THE REGION TUESDAY NIGHT INTO WEDNESDAY.
HOWEVER...SOME ISOLATED CONVECTION MAY FORM ACROSS THE SOUTHWESTERN
HIGH TERRAIN CLOSER TO THE FRONTAL BOUNDARY WITH BETTER INSTABILITY.
WEDNESDAY NIGHT INTO FRIDAY...THE HIGH CENTER OVER NEW ENGLAND WILL
SLOWLY MOVE EAST TOWARDS THE ATLANTIC OCEAN.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 800 AM EDT FRIDAY...
EXTENDED PERIOD OF MVFR OR WORSE CIGS/VSBYS EXPECTED ACROSS THE
CWA.
COLD FRONT WILL BECOME NEARLY STATIONARY AND ORIENTED EAST-WEST
JUST SOUTH OF THE REGION TODAY. THIS BOUNDARY WILL BECOME THE
FOCUS FOR OVERRUNNING MOISTURE WHICH WILL RESULT IN PERIODS OF
-RA/DZ THROUGH MUCH OF THE UPCOMING WEEKEND.
NORTH TO NORTHEAST WINDS TODAY WILL BECOME EASTERLY TONIGHT. THIS
EASTERLY UPSLOPE FLOW WILL LIKELY RESULT IN LOWERING CLOUD BASES
THAT WILL OBSCURE THE RIDGES TONIGHT...A PERSISTENT DRIZZLE
DEVELOPING OVER MOST OF THE FORECAST AREA IN ADDITION TO PERIODS
OF RAIN...CONDITIONS LOWERING TO IFR.
EXTENDED AVIATION DISCUSSION...
NOT EXPECTING MUCH IF ANY IMPROVEMENT THROUGH THE WEEKEND...EVEN
AFTER THE -RA ENDS SUNDAY...LOW LEVEL CLOUDINESS WILL REMAIN.
BEYOND SUNDAY...LOW CONFIDENCE. MODELS SHOWING OVERALL MVFR TO
PERSIST INTO MONDAY BEFORE SOUTHWEST WINDS ALOFT BEGIN TO RESULT
IN IMPROVING CONDITIONS. EVEN THOUGH LOW CLOUDS ERODE ON
MONDAY...LINGERING MOISTURE EXPECTING POTENTIAL FOR MVFR AT TIMES
IN SPOTTY SHOWERS MONDAY AFTERNOON AS ANOTHER UPPER TROUGH
APPROACHES THE REGION FROM THE WEST.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PM
NEAR TERM...AMS/PM
SHORT TERM...NF
LONG TERM...NF
AVIATION...PM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
600 PM CDT FRI SEP 12 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 257 PM CDT FRI SEP 12 2014
MAIN FORECAST CONCERNS ARE FROST AND FOG POTENTIAL TONIGHT.
LATEST WATER VAPOR SATELLITE IMAGERY SHOWING VIGOROUS SHORTWAVE
TROUGH OVER THE NORTHERN PLAINS. MOSAIC RADAR INDICATING
FRONTOGENETICAL BAND OF RAIN EXTENDING FROM NORTHEAST WISCONSIN INTO
NORTHEAST IOWA PER 12.15Z RAP 700-600MB FN VECTOR CONVERGENCE.
ALSO...MOSAIC RADAR SHOWING DIURNALLY DRIVEN SCATTERED SHOWERS OVER
CENTRAL MINNESOTA UNDERNEATH MAIN SHORTWAVE TROUGH.
TONIGHT...SHORTWAVE TROUGH AND ASSOCIATED LOW LEVEL MOISTURE/RAIN
PROGGED TO PUSH QUICKLY EAST INTO MICHIGAN THIS EVENING PER THE
LATEST 12.12Z GFS/NAM AND 12.15Z RAP RELATIVE HUMIDITY FIELDS. THIS
IS EVIDENT PER LATEST VISIBLE SATELLITE IMAGERY SHOWING DIURNAL
CUMULUS FIELD WEST OF A LINE FROM FAIRMONT MINNESOTA TO NEAR DULUTH
MINNESOTA. THIS CUMULUS FIELD WILL QUICKLY EVAPORATE DUE TO LOSS OF
DAYTIME HEATING THIS EVENING AND ALLOW SKIES TO CLEAR WEST TO EAST
ACROSS THE FORECAST AREA. SURFACE RIDGE BUILDS INTO THE FORECAST
AREA BY 06Z AND PRODUCE CALM WINDS AND DRIER AIRMASS TO ADVECT IN.
TEMPERATURES WILL BE ABLE TO FALL RAPIDLY INTO THE 30S AND THE UPPER
20S IN THE COLD SPOTS OF CENTRAL WISCONSIN. FOR THIS...A FROST
ADVISORY WILL BE IN EFFECT FOR PORTIONS OF SOUTHEAST
MINNESOTA...NORTHEAST IOWA AND CENTRAL WISCONSIN TONIGHT. IN
ADDITION...THE COMBINATION OF RAIN TODAY...CALM WINDS AND INVERSION
DEVELOPING TONIGHT PER BUFKIT SOUNDINGS...AREAS OF FOG WILL DEVELOP
IN RIVER VALLEYS AND PARTS OF CENTRAL WISCONSIN AFTER 06Z.
DRY WEATHER CONDITIONS AND UNSEASONABLY COOL TEMPERATURES WILL
PREVAIL ACROSS THE AREA SATURDAY...AS SURFACE RIDGE REMAINS IN
CONTROL.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 257 PM CDT FRI SEP 12 2014
WARMER AIR ADVECTS INTO THE FORECAST AREA SUNDAY OUT AHEAD OF NEXT
SHORTWAVE TROUGH TO AFFECT THE REGION. TEMPERATURES WILL BE A FEW
DEGREES WARMER AND SLIGHTLY BELOW NORMAL.
NEXT CONCERN IS SHORTWAVE TROUGH MOVING OVER THE GREAT LAKES REGION
EMBEDDED IN THE WEST TO NORTHWEST FLOW SUNDAY NIGHT INTO MONDAY.
BOTH THE 12.12Z GFS/NAM SHOW STRONG PV ADVECTION/QG FORCING AND
FN CONVERGENCE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST
AREA. SOME SLIGHT DIFFERENCES OCCUR WITH THE PLACEMENT AND TIMING
OF SURFACE FEATURES BETWEEN THE 12.12Z GFS/NAM/ECMWF. WITH THE
MODELS CONTINUE TO SHOW DECENT DYNAMIC FORCING/LIFT IN ASSOCIATED
WITH SHORTWAVE TROUGH...WILL MAINTAIN PRECIPITATION CHANCES SUNDAY
INTO MONDAY MAINLY FOR THE SOUTHERN HALF OF THE FORECAST AREA.
MAIN FORECAST CONCERN ARE PRECIPITATION CHANCES FRIDAY...OTHERWISE
TEMPERATURES TUESDAY THROUGH FRIDAY. THE 12.12Z GFS/GEM/ECMWF
CONTINUE TO HAVE GOOD RUN TO RUN CONSISTENCY IN DIGGING UPPER LEVEL
TROUGH OVER THE NORTHEAST UNITED STATES AND GREAT LAKES REGION AND
SURFACE RIDGE DOMINATING THE UPPER MIDWEST TUESDAY THROUGH THURSDAY.
WITH SUBSIDENCE OVER THE FORECAST AREA...DUE TO SURFACE RIDGE...DRY
WEATHER CONDITIONS CAN BE EXPECTED ACROSS THE FORECAST AREA DURING
THIS TIME FRAME. TEMPERATURES SHOULD BE NEAR OR SLIGHTLY BELOW
NORMAL TUESDAY THROUGH THURSDAY...AS THE 12.00Z GFS/GEM/ECMWF
INDICATE 850MB TEMPERATURES RANGING FROM PLUS 5 TO PLUS 10 DEGREES
CELSIUS AND 12.12Z GEFS SHOW STANDARD ANOMALIES OF MINUS 0.5 TO
MINUS 1 DEGREE CELSIUS. SIGNIFICANT DIFFERENCES SHOW UP BETWEEN THE
12.12Z GFS/ECMWF FRIDAY...AS THE 12.12Z GFS MORE AMPLIFIED WITH
UPPER LEVEL RIDGE OVER THE UPPER MIDWEST THAN THE ECMWF AND THE
12.12Z ECMWF IS SLOWER IN PROGRESSING THE UPPER LEVEL RIDGE INTO THE
UPPER MIDWEST AND GREAT LAKES REGION. THIS HAS IMPACTS ON HOW FAST
WARMER AIR ADVECTS INTO THE REGION AND TIMING OF SURFACE WARM FRONT
INTO THE FORECAST AREA. THIS SURFACE WARM FRONT WILL BE THE FOCUS
OF PRECIPITATION CHANCES FRIDAY...WITH BOTH THE 12.12Z GFS/ECMWF
INDICATE DECENT 850MB MOISTURE TRANSPORT AND CONVERGENCE IN
ASSOCIATION WITH IMPULSE OVER THE NORTHERN PLAINS AND NORTHERN
ROCKIES. CONFIDENCE IN FORECAST ON FRIDAY IS LOW DUE TO TIMING AND
STRENGTH OF UPPER LEVEL RIDGE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 600 PM CDT FRI SEP 12 2014
LOTS OF DIURNAL ELEMENTS TO THE CLOUDS WEST OF THE MISSISSIPPI RIVER
EARLY THIS EVENING...AND EXPECT THESE TO QUICKLY DISSIPATE WITH
SUNDOWN. IN THE EAST...THE CLOUD MASS IS ASSOCIATED WITH A DEPARTING
UPPER LEVEL SHORTWAVE...AND THESE WILL TAKE A BIT LONGER TO CLEAR.
KRST SHOULD SCATTER OUT EARLY THIS EVENING...WHILE IT MIGHT HOLD OFF
UNTIL AFTER 03Z FOR THE CLEARING LINE TO REACH KLSE.
WITH CLOUDS HOLDING T/TD SPREADS CLOSE THROUGH THE DAY...AND
CLEARING SKIES JUST IN TIME FOR NIGHTTIME...ITS A FAVORABLE SETUP
FOR DIURNAL COOLING INDUCED RIVER VALLEY FOG. NOT AS MUCH T/TD
SPREAD TO MAKEUP. SFC WINDS ARE ALSO EXPECTED TO BE LIGHT THROUGH
THE NIGHT. HOWEVER...A SIGNIFICANT DRAWBACK WILL BE THE DEPTH OF THE
LIGHT WIND LAYER. RAP/NAM BUFKIT SOUNDINGS SUGGEST AT 10+ KTS OF
WIND BY 300 FT FOR MOST OF THE NIGHT. GENERALLY...THIS IT NOT
FAVORABLE FOR DENSE FOG. CERTAINLY...SOME VSBY RESTRICTIONS ARE
POSSIBLE...AND COULD SEE THICKER FOG/STRATUS BANK SITTING ON THE
MISSISSIPPI RIVER...BUT UNSURE IF IT WILL SPREAD ACROSS KLSE.
SOMETHING TO WATCH CLOSELY TONIGHT.
HIGH PRESSURE BUILDS IN SATURDAY...AND WILL RESULT IN VFR CONDITIONS
OUTSIDE OF THE EARLY MORNING FOG POTENTIAL. WINDS WILL GRADUALLY
SWING FROM WEST TO SOUTHWEST. LATER SAT NIGHT...SOME CIGS NEAR 4KFT
COULD RETURN AS LOW LEVEL WARM AIR ADVECTION AND WEAK MOISTURE
TRANSPORT LEAD A SHORTWAVE MOVING EAST ACROSS THE NORTHERN PLAINS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY FROM 3 AM TO 8 AM CDT SATURDAY FOR WIZ017-029-033-
034-042>044.
MN...FROST ADVISORY FROM 3 AM TO 8 AM CDT SATURDAY FOR MNZ086-087-094-
095.
IA...FROST ADVISORY FROM 3 AM TO 8 AM CDT SATURDAY FOR IAZ008>010-018-
019-029.
&&
$$
SHORT TERM...DTJ
LONG TERM...DTJ
AVIATION...RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
257 PM CDT FRI SEP 12 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 257 PM CDT FRI SEP 12 2014
MAIN FORECAST CONCERNS ARE FROST AND FOG POTENTIAL TONIGHT.
LATEST WATER VAPOR SATELLITE IMAGERY SHOWING VIGOROUS SHORTWAVE
TROUGH OVER THE NORTHERN PLAINS. MOSAIC RADAR INDICATING
FRONTOGENETICAL BAND OF RAIN EXTENDING FROM NORTHEAST WISCONSIN INTO
NORTHEAST IOWA PER 12.15Z RAP 700-600MB FN VECTOR CONVERGENCE.
ALSO...MOSAIC RADAR SHOWING DIURNALLY DRIVEN SCATTERED SHOWERS OVER
CENTRAL MINNESOTA UNDERNEATH MAIN SHORTWAVE TROUGH.
TONIGHT...SHORTWAVE TROUGH AND ASSOCIATED LOW LEVEL MOISTURE/RAIN
PROGGED TO PUSH QUICKLY EAST INTO MICHIGAN THIS EVENING PER THE
LATEST 12.12Z GFS/NAM AND 12.15Z RAP RELATIVE HUMIDITY FIELDS. THIS
IS EVIDENT PER LATEST VISIBLE SATELLITE IMAGERY SHOWING DIURNAL
CUMULUS FIELD WEST OF A LINE FROM FAIRMONT MINNESOTA TO NEAR DULUTH
MINNESOTA. THIS CUMULUS FIELD WILL QUICKLY EVAPORATE DUE TO LOSS OF
DAYTIME HEATING THIS EVENING AND ALLOW SKIES TO CLEAR WEST TO EAST
ACROSS THE FORECAST AREA. SURFACE RIDGE BUILDS INTO THE FORECAST
AREA BY 06Z AND PRODUCE CALM WINDS AND DRIER AIRMASS TO ADVECT IN.
TEMPERATURES WILL BE ABLE TO FALL RAPIDLY INTO THE 30S AND THE UPPER
20S IN THE COLD SPOTS OF CENTRAL WISCONSIN. FOR THIS...A FROST
ADVISORY WILL BE IN EFFECT FOR PORTIONS OF SOUTHEAST
MINNESOTA...NORTHEAST IOWA AND CENTRAL WISCONSIN TONIGHT. IN
ADDITION...THE COMBINATION OF RAIN TODAY...CALM WINDS AND INVERSION
DEVELOPING TONIGHT PER BUFKIT SOUNDINGS...AREAS OF FOG WILL DEVELOP
IN RIVER VALLEYS AND PARTS OF CENTRAL WISCONSIN AFTER 06Z.
DRY WEATHER CONDITIONS AND UNSEASONABLY COOL TEMPERATURES WILL
PREVAIL ACROSS THE AREA SATURDAY...AS SURFACE RIDGE REMAINS IN
CONTROL.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 257 PM CDT FRI SEP 12 2014
WARMER AIR ADVECTS INTO THE FORECAST AREA SUNDAY OUT AHEAD OF NEXT
SHORTWAVE TROUGH TO AFFECT THE REGION. TEMPERATURES WILL BE A FEW
DEGREES WARMER AND SLIGHTLY BELOW NORMAL.
NEXT CONCERN IS SHORTWAVE TROUGH MOVING OVER THE GREAT LAKES REGION
EMBEDDED IN THE WEST TO NORTHWEST FLOW SUNDAY NIGHT INTO MONDAY.
BOTH THE 12.12Z GFS/NAM SHOW STRONG PV ADVECTION/QG FORCING AND
FN CONVERGENCE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST
AREA. SOME SLIGHT DIFFERENCES OCCUR WITH THE PLACEMENT AND TIMING
OF SURFACE FEATURES BETWEEN THE 12.12Z GFS/NAM/ECMWF. WITH THE
MODELS CONTINUE TO SHOW DECENT DYNAMIC FORCING/LIFT IN ASSOCIATED
WITH SHORTWAVE TROUGH...WILL MAINTAIN PRECIPITATION CHANCES SUNDAY
INTO MONDAY MAINLY FOR THE SOUTHERN HALF OF THE FORECAST AREA.
MAIN FORECAST CONCERN ARE PRECIPITATION CHANCES FRIDAY...OTHERWISE
TEMPERATURES TUESDAY THROUGH FRIDAY. THE 12.12Z GFS/GEM/ECMWF
CONTINUE TO HAVE GOOD RUN TO RUN CONSISTENCY IN DIGGING UPPER LEVEL
TROUGH OVER THE NORTHEAST UNITED STATES AND GREAT LAKES REGION AND
SURFACE RIDGE DOMINATING THE UPPER MIDWEST TUESDAY THROUGH THURSDAY.
WITH SUBSIDENCE OVER THE FORECAST AREA...DUE TO SURFACE RIDGE...DRY
WEATHER CONDITIONS CAN BE EXPECTED ACROSS THE FORECAST AREA DURING
THIS TIME FRAME. TEMPERATURES SHOULD BE NEAR OR SLIGHTLY BELOW
NORMAL TUESDAY THROUGH THURSDAY...AS THE 12.00Z GFS/GEM/ECMWF
INDICATE 850MB TEMPERATURES RANGING FROM PLUS 5 TO PLUS 10 DEGREES
CELSIUS AND 12.12Z GEFS SHOW STANDARD ANOMALIES OF MINUS 0.5 TO
MINUS 1 DEGREE CELSIUS. SIGNIFICANT DIFFERENCES SHOW UP BETWEEN THE
12.12Z GFS/ECMWF FRIDAY...AS THE 12.12Z GFS MORE AMPLIFIED WITH
UPPER LEVEL RIDGE OVER THE UPPER MIDWEST THAN THE ECMWF AND THE
12.12Z ECMWF IS SLOWER IN PROGRESSING THE UPPER LEVEL RIDGE INTO THE
UPPER MIDWEST AND GREAT LAKES REGION. THIS HAS IMPACTS ON HOW FAST
WARMER AIR ADVECTS INTO THE REGION AND TIMING OF SURFACE WARM FRONT
INTO THE FORECAST AREA. THIS SURFACE WARM FRONT WILL BE THE FOCUS
OF PRECIPITATION CHANCES FRIDAY...WITH BOTH THE 12.12Z GFS/ECMWF
INDICATE DECENT 850MB MOISTURE TRANSPORT AND CONVERGENCE IN
ASSOCIATION WITH IMPULSE OVER THE NORTHERN PLAINS AND NORTHERN
ROCKIES. CONFIDENCE IN FORECAST ON FRIDAY IS LOW DUE TO TIMING AND
STRENGTH OF UPPER LEVEL RIDGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1237 PM CDT FRI SEP 12 2014
MID LEVEL FRONTOGENETIC BAND PRODUCING RAIN MUCH OF TODAY CONTINUES
TO PRODUCE MVFR TO VFR CEILINGS. BULK OF LOWER CEILINGS ARE SOUTH
AND EAST OF TAF SITES...WITH CONDITIONS EXPECTED TO IMPROVE LATE IN
THE DAY AS THESE BANDS MOVE OFF WITH SHORT WAVE FORCING.
RAPID CLEARING EXPECTED GOING INTO THIS EVENING AS SURFACE RIDGE
BUILDS IN. WITH CLEARING SKIES...MOIST LOW LEVELS AND LIGHT WINDS...
SOME VALLEY FOG EXPECTED...ESPECIALLY SOUTH AND EAST OF KLSE. EXTENT
OF THIS UNCLEAR WITH 10-15 KTS ON HIGHER SIDE OF BOUNDARY LAYER.
VFR CONDITIONS WILL PREVAIL SATURDAY ONCE VALLEY FOG BURNS OFF AS
SURFACE RIDGE PASSES THROUGH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY FROM 3 AM TO 8 AM CDT SATURDAY FOR WIZ017-029-033-
034-042>044.
MN...FROST ADVISORY FROM 3 AM TO 8 AM CDT SATURDAY FOR MNZ086-087-094-
095.
IA...FROST ADVISORY FROM 3 AM TO 8 AM CDT SATURDAY FOR IAZ008>010-018-
019-029.
&&
$$
SHORT TERM...DTJ
LONG TERM...DTJ
AVIATION...SHEA
AREA FORECAST DISCUSSION
NWS MIAMI FL
402 AM EDT SUN SEP 14 2014
.SHORT TERM...(TODAY-TUESDAY)
THE EARLY MORNING SURFACE ANALYSIS SHOWED SOUTHEAST FLOW ACROSS THE
LOCAL AREA WITH A WEAK FRONTAL BOUNDARY EXTENDING SW ACROSS THE
REGION TO THE NORTH AND A WEAK TROUGH OF LOW PRESSURE CENTERED OVER
THE CENTRAL GULF OF MEXICO. THE LATEST WATER VAPOR LOOP SHOWED A
COMPLEX MID/UPPER LEVEL PATTERN ACROSS THE REGION CHARACTERIZED WITH
A RIDGE AXIS ORIENTED FROM EAST TO WEST OVER THE NORTHERN GULF COAST
STATES AND TWO UPPER LOWS EAST AND WEST OF THE FLORIDA PENINSULA.
PLENTY OF MID-UPPER MOISTURE CONTINUES TO LIFT NORTH OVER THE AREA
EAST OF THE UPPER LOW OVER THE GULF OF MEXICO...WHICH SUPPORTS THE
WIDESPREAD SHOWER ACTIVITY OVER THE ATLANTIC AND EAST COAST
LOCATIONS THIS MORNING. THE LATEST HRRR MODEL RUN HAS INITIALIZED
WELL WITH THIS ACTIVITY AND GENERALLY INDICATES A LARGE SHIELD OF
MAINLY LIGHT TO MODERATE RAIN REMAINING POSSIBLE THROUGH THE MID-
MORNING HOURS BEFORE DIMINISHING. LATER THIS AFTERNOON THE LATEST
MODEL SOUNDINGS INDICATE SOME DRIER FILLING IN FROM THE SOUTHEAST
WITH PWS DROPPING TOWARD 1.6" OVER THE SE FLORIDA COAST AND
INCREASING TO OVER THE 2" MARK BETWEEN NAPLES AND THE LAKE LATER
TODAY. THIS GRADIENT WILL BE REFLECTED IN THE LATEST FORECAST
PACKAGE SHOWING THE GREATEST RAINFALL CHANCES ALONG THE SOUTHEAST
FLORIDA COAST THROUGH THE MORNING HOURS AND ACROSS THE INTERIOR AND
LAKE REGION LATER THIS AFTERNOON THROUGH THIS EVENING. MONDAY
THROUGH TUESDAY...CONDITIONS ARE EXPECTED TO TREND BACK TOWARD
NORMAL AS SOME ADDITIONAL MID-LEVEL DRY AIR MOVES INTO THE AREA.
EASTERLY LOW-LEVEL FLOW UP TO 700 MB WILL PERSIST THROUGH THIS
TIME...WHICH WILL KEEP THE DIURNALLY DRIVEN CONVECTIVE ACTIVITY
FOCUSED INLAND AND TOWARD THE GULF COAST EACH AFTERNOON/EVENING.
/85
.LONG TERM (WEDNESDAY-FRIDAY)...
THE LATEST EXTENDED GUIDANCE REMAINS IN DECENT AGREEMENT AND
GENERALLY INDICATES FALLING UPPER HEIGHTS IN RESPONSE TO A DEEPENING
UPPER TROUGH ACROSS THE REGION. A FRONTAL BOUNDARY IS PROJECTED TO
SHIFT SOUTHWARD TOWARD AND POSSIBLY INTO THE LOCAL AREA BEFORE
STALLING. THE GFS AND ECMWF HAVE COME INTO BETTER AGREEMENT IN THIS
00Z CYCLE REGARDING THE SOUTHWARD PROGRESSION OF THIS BOUNDARY
MOVING INTO THE AREA BY THURSDAY DUE TO A SHORTWAVE WRAPPING AROUND
THE BASE OF THE UPPER TROUGH NORTH OF THE AREA AND SFC WAVE
DEVELOPING ALONG THE BOUNDARY OFF OF THE GA/SC COAST BY THURSDAY.
THIS SHOULD TRANSLATE TO A WET PATTERN FOR SOUTH FLORIDA WITH SW LOW-
LEVEL FLOW AHEAD OF THE BOUNDARY AND PLENTY OF DEEP LAYER MOISTURE.
THE HIGHEST RAINFALL PROBABILITIES ARE PROJECTED TO SET UP AND
FOCUSING ALONG THE EAST COAST AREAS EACH AFTERNOON GOING INTO THE
WEEKEND EACH DAY.
/85
&&
.AVIATION...
SHOWERS AND STORMS WERE ONGOING ACROSS THE ATLANTIC WATERS...AND
ISOLATED SHOWERS WERE MOVING BACK INTO THE EAST COAST NEAR KFLL.
SHOWERS MAY MOVE BACK INTO THE EAST COAST OVERNIGHT AND THEN TAPER
OFF IN THE MORNING. BRIEF MVFR/IFR CONDITIONS ARE POSSIBLE. GUIDANCE
IS INDICATING DRIER AIR MAY BEGIN MOVING INTO THE EASTERN PORTIONS
OF THE REGION IN THE AFTERNOON. SO REMOVED VCTS FOR THE EAST COAST
METRO AREAS FOR THE AFTERNOON HOURS. LIGHT WINDS EARLY THIS MORNING
WILL BECOME SOUTHEAST AROUND 10 KNOTS IN THE AFTERNOON...AND THEN
DIMINISH AGAIN IN THE EVENING. FOR KAPF...A WEAK GULF COAST SEA
BREEZE MAY DEVELOP IN THE AFTERNOON. THE BEST CHANCE OF STORMS NEAR
KAPF IS ALSO FORECAST TO BE IN THE AFTERNOON.
/84
&&
.MARINE...
AN UPPER LOW WILL KEEP THE RAIN CHANCES IN THE FORECAST ACROSS THE
MARINE AREAS THROUGH THE REMAINDER OF THE WEEKEND WITH LIGHT TO
MODERATE SOUTHEAST WINDS CONTINUING. WINDS AND SEAS WILL BE LOCALLY
HIGHER IN AND AROUND HEAVIER SHOWERS AND STORMS. HIGH PRESSURE WILL
BUILD BACK ACROSS THE REGION THROUGH THE FIRST HALF OF THE UPCOMING
WEEK WITH SOUTHEAST WINDS CONTINUING. A COLD FRONT WILL APPROACH
FROM THE NORTH AND MAY LEAD TO SOUTH AND SOUTHWEST WINDS BY THE END
OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 76 87 76 / 60 20 50 20
FORT LAUDERDALE 88 79 88 79 / 50 20 50 10
MIAMI 87 78 88 78 / 50 20 50 10
NAPLES 87 76 89 76 / 60 20 40 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION...85/AG
AVIATION....84/AK
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
349 AM EDT Sun Sep 14 2014
.Near Term [Through Today]...
The 11 pm EDT regional surface analysis showed a quasi-stationary
front from the southeast LA coast, through Columbus, GA, to the east
coast of NC. Outflow from the numerous storms Saturday evening had
flipped the winds across much of our forecast area to the north, but
that was not the cold front, and we expect these winds to return to
light E-SE flow later this morning. Vapor imagery and upper air data
showed a narrow ridge along the Gulf Coast, so we don`t expect any
further progress of the aforementioned front, and very little (if
any) Q-G forcing. However, deep layer moisture remains plentiful,
and mesoscale forcing and/or weak convergence near the nearby front
will help generate scattered deep moist convection this afternoon.
Our PoP is in the 30-50% range, with the highest PoP north of Dothan
and Albany (nearest the frontal system), and around the Panama City
area (where the CAMs show more favorable sea breeze forcing). Highs
will be in the lower to mid 90s. The synoptic environment doesn`t
appears favorable for widespread flooding and/or severe storms,
though we can`t completely rule out an isolated, marginal incident
of either.
.Short Term [Tonight Through Tuesday]...
Rain chances will be gradually increasing through the short term
period as the "dirty" upper level ridge (with plenty of deep layer
moisture still underneath it) continues to weaken over the next
couple of days, before being replaced by a slowly steepening trof
over the SE U.S. by Tuesday and Wednesday. Lingering PoPs this
evening will range from 30% over much of the interior, with a small
area of 40%s across N portions of our AL and GA zones. On Monday, as
the southerly flow increases over the region, PoPs will rise from
40% south and 30% north in the morning, to 50% south and 60% north
by the afternoon, and once again linger well into the evening hours.
On Tuesday, as the upper level trof begins to become better
established, widespread 60% PoPs (with even a few areas of 70%) are
expected across the CWA. This pattern change could result in the
potential for more widespread heavy rainfall over the region through
mid week, before a significant punch of drier air works into the
area from the northwest by the end of the week as mentioned in the
long term discussion below. Initially, temps should still average a
few degrees above climo, but high temps on Tuesday may need a slight
downward adjustment based on the final cloud cover and rainfall
chances.
.Long Term [Tuesday Night Through Saturday]...
Deep moisture will continue to be present across the area with a
stalled frontal boundary also in the vicinity. These ingredients
point to an unsettled period coming up with an above average chance
of rain on Tuesday and Wednesday. Some locally heavy rain is
possible given the weak boundary and deep tropical moisture
expected to be in place. A drying trend is possible for most of
the area with the exception of the southeast big bend near the end
of the week as the deepest moisture may get pushed to the south.
Daytime highs are expected to be near to slightly below normal
through most of the week.
&&
.Aviation...
[through 06z Monday] There were some mixed signals among the latest
NWP guidance for the overnight and early morning period. Based on
recent rain and satellite imagery (which showed a gradual clearing
trend across much of our forecast area), we think there is a good
chance for periods of low-end MVFR cigs and vis at KDHN, KECP, and
KABY between 10z and 14z. (The 02z HRRR forecast LIFR conditions,
while most of the MOS forecast high-end MVFR conditions). Generally
VFR conditions are expected by late morning through afternoon and
evening, except in isolated to scattered TSRA. The highest PoP is at
KECP. Elsewhere the PoP is currently too low to mention TSRA in the
TAFs.
&&
.Marine...
Winds and seas will remain a bit elevated across the offshore legs
today and Monday, as a trough of low pressure (the remnants of a
weak tropical disturbance) passes well to the south of the marine
area. Thereafter, light winds and low seas are expected over the
coastal waters as a weak surface pressure returns to the marine
area.
&&
.Fire Weather...
Red Flag conditions are not expected through at least mid week.
&&
.Hydrology...
Although areas of locally heavy rainfall will be possible through
mid-week, at this time it does not appear as though there will be
enough time or organization to this precipitation to cause a
widespread impact on our area rivers and streams. However, the
situation does still bear monitoring, and if the steepening of the
upper level trof and subsequent cold frontal passage are slightly
slower than expected, the hydrological outlook may need to be
re-visited.
&&
.Preliminary Point Temps/PoPs...
Tallahassee 93 72 93 72 91 / 30 30 50 30 60
Panama City 90 77 89 76 88 / 50 30 50 30 60
Dothan 91 71 92 71 91 / 30 30 60 40 60
Albany 91 71 92 72 92 / 40 40 60 40 60
Valdosta 92 71 93 71 92 / 30 30 60 30 60
Cross City 92 71 91 71 91 / 30 30 50 30 60
Apalachicola 89 77 88 77 87 / 30 30 50 30 60
&&
.TAE Watches/Warnings/Advisories...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...FOURNIER
SHORT TERM...GOULD
LONG TERM...DVD
AVIATION...FOURNIER
MARINE...GOULD
FIRE WEATHER...FOURNIER
HYDROLOGY...GOULD
AREA FORECAST DISCUSSION
NWS MIAMI FL
146 AM EDT SUN SEP 14 2014
.AVIATION...
SHOWERS AND STORMS WERE ONGOING ACROSS THE ATLANTIC WATERS...AND
ISOLATED SHOWERS WERE MOVING BACK INTO THE EAST COAST NEAR KFLL.
SHOWERS MAY MOVE BACK INTO THE EAST COAST OVERNIGHT AND THEN TAPER
OFF IN THE MORNING. BRIEF MVFR/IFR CONDITIONS ARE POSSIBLE. GUIDANCE
IS INDICATING DRIER AIR MAY BEGIN MOVING INTO THE EASTERN PORTIONS
OF THE REGION IN THE AFTERNOON. SO REMOVED VCTS FOR THE EAST COAST
METRO AREAS FOR THE AFTERNOON HOURS. LIGHT WINDS EARLY THIS
MORNING WILL BECOME SOUTHEAST AROUND 10 KNOTS IN THE
AFTERNOON...AND THEN DIMINISH AGAIN IN THE EVENING. FOR KAPF...A
WEAK GULF COAST SEA BREEZE MAY DEVELOP IN THE AFTERNOON. THE BEST
CHANCE OF STORMS NEAR KAPF IS ALSO FORECAST TO BE IN THE
AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 927 PM EDT SAT SEP 13 2014/
UPDATE...
DEEP TROPICAL FLOW REMAINS IN PLACE ACROSS SOUTH FLORIDA AS
EVIDENCED ON THE 00Z MFL SOUNDING THIS EVENING. THE PWAT IS JUST
OVER TWO INCHES WHICH IS SLIGHTLY ABOVE THE AVERAGE FOR MID
SEPTEMBER. SATELLITE AND RADAR SIGNATURES ALSO REFLECT THIS WITH
AMPLE SHOWER ACTIVITY WITH SOME EMBEDDED TSRA. SO NO CHANGES ARE
PLANNED AT THIS TIME AND WILL KEEP HIGH END CHANCES FOR RAIN
THROUGH THE NIGHT.
KOB
PREV DISCUSSION... /ISSUED 812 PM EDT SAT SEP 13 2014/
AVIATION...
EXTENSIVE CLUSTER OF SHOWERS AND THUNDERSTORMS THAT EXITED CUBA
THIS AFTERNOON IS PROGRESSING INTO MIAMI-DADE COUNTY AT TAF
ISSUANCE TIME. TEMPO TSRA GROUPS FOR ALL MIAMI-DADE TERMINALS
THROUGH 2Z...WITH VCTS AREAWIDE UNTIL 6Z. LOCALLY GUSTY WINDS...35
KNOTS CANT BE RULED OUT...AND SIGNIFICANT RESTRICTIONS POSSIBLE
WITH THIS ACTIVITY. BY MIDNIGHT...UNCERTAIN ON SHWR/TSTM COVERAGE
AS GUIDANCES SUGGESTS CLIMATOLOGICALLY UNUSUAL OCCURRENCE OF
SHOWERS/TSTMS INTO SUNDAY MORNING. FOR NOW WILL HANDLE WITH
VCSH...ALTHOUGH PERIODS OF THUNDER QUITE POSSIBLE...ESPECIALLY
CONSIDERING LAST NIGHT HAD SIMILAR ACTIVITY. THUNDERSTORMS SHOULD
REINVIGORATE BY LATE MORNING. AWAY FROM CONVECTION...ESE WINDS 5
KTS OVERNIGHT...10-15 KTS SUNDAY.
PREV DISCUSSION... /ISSUED 348 PM EDT SAT SEP 13 2014/
DISCUSSION...
THE LATEST CONSENSUS OF THE MODEL GUIDANCE...BOTH THE GLOBAL
MODELS AND THE LATEST HRRR RUN...INDICATE THE POTENTIAL FOR
SHOWERS AND THUNDERSTORMS TO FORM ACROSS THE FLORIDA STRAITS THIS
EVENING AND AFFECT THE SOUTHERN PORTIONS OF SOUTH FLORIDA AND
ADJACENT WATERS LATER THIS EVENING AND POSSIBLY CONTINUING INTO
THE EARLY MORNING HOURS ON SUNDAY. RECENT SATELLITE IMAGERY AND
RADAR RETURNS INDICATE THIS PROCESS IS ALREADY UNDERWAY WITH BANDS
OF SHOWERS AND THUNDERSTORMS OBSERVED ACROSS THE FLORIDA STRAITS.
OVER NIGHT AND INTO SUNDAY...A BROAD AREA OF SURFACE LOW PRESSURE
ACROSS THE EASTERN GULF WILL CONTINUE TO TRACK WESTWARD INTO THE
CENTRAL GULF. THE MORE RECENT GUIDANCE HAS CONSISTENTLY BEEN
INDICATING THAT DEEP TROPICAL MOISTURE WILL CONTINUE TO LINGER
ACROSS SOUTH FLORIDA AND ADJACENT WATERS WITH LOW LEVEL MASS AND
MOISTURE CONVERGENCE CONTINUING ACROSS THE REGION INTO SUNDAY
MORNING. IN ADDITION THE UPPER LEVEL WINDS COULD BE FAVORABLE FOR
SPEED DIVERGENCE DURING THE AFTERNOON HOURS. DAY TIME HEATING AND
WITH THE LINGERING DEEP MOISTURE WILL ALLOW FOR AFTERNOON
CONVECTION ON SUNDAY WITH THE GREATEST COVERAGE OF SHOWERS AND
THUNDERSTORMS EXPECTED INLAND AND WEST.
FOR MONDAY AND TUESDAY...SOME RELATIVELY DRIER AIR IS FORECAST TO
ENTER THE REGION ALTHOUGH THE GUIDANCE CONSENSUS INDICATES THAT
LINGERING MOISTURE COULD BE SUFFICIENT FOR AFTERNOON SHOWERS AND
THUNDERSTORMS...MAINLY OVER THE THE PENINSULA. THE EXTENDED
GUIDANCE CONTINUES TO SUGGEST THAT LATE NEXT WEEK DEEP MOISTURE
COULD EXTEND FROM THE YUCATAN PENINSULA NORTHEASTWARD ACROSS SOUTH
FLORIDA AND INTO THE WESTERN ATLANTIC WITH A LARGE AMPLITUDE UPPER
LEVEL TROUGH DEEPENING INTO THE CENTRAL GULF. THIS PATTERN IS
FORECAST TO LINGER INTO NEXT WEEKEND WITH THE POTENTIAL FOR
WIDESPREAD LOCAL CONVECTION.
MARINE...
MAINLY EASTERLY WINDS ARE FORECAST TO BE IN THE 10 TO 15 KNOT
RANGE ACROSS THE REGIONAL WATERS TONIGHT THROUGH SUNDAY THEN
SLOWLY DECREASING INTO EARLY NEXT WEEK WHILE REMAINING EASTERLY.
REGIONAL SEAS ARE FORECAST TO BE MAINLY AROUND 2 FEET OR LESS THE
REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 76 87 76 / 60 20 50 20
FORT LAUDERDALE 88 79 88 79 / 50 20 50 10
MIAMI 87 78 88 78 / 50 20 50 10
NAPLES 87 76 89 76 / 60 20 40 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...85/AG
LONG TERM....85/AG
AVIATION...84/AK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1151 PM CDT SAT SEP 13 2014
.UPDATE...
ISSUED AT 1149 PM CDT SAT SEP 13 2014
A ROUGHLY 75 MILE WIDE AREA OF LOW CLOUDS...EVIDENT ON IR IMAGERY EXTENDING
NORTHEAST FROM NE KS...THROUGH NW IA INTO NW WI APPEARED TO BE
ASSOCIATED WITH AN AXIS OF MOISTURE CONVERGENCE AND WARM ADVECTION
AROUND THE 800 MB LEVEL AS SEEN ON THE 00Z KOMA SOUNDING. THIS
WILL CONTINUE TO PROGRESS EASTWARD OVERNIGHT FOLLOWING AN ELEVATED
WARM FRONT LINKED TO AN UPPER LEVEL TROUGH MOVING THROUGH
MANITOBA. WHILE THE LATEST RAP RUNS HAVE MOISTURE DEPICTED AT
THIS LEVEL MIGRATING EASTWARD INTO THE FORECAST AREA BY MORNING...THE
ASSOCIATED ISENTROPIC LIFT AND CONDENSATION PRESSURE DEFICITS
OVERALL DEPICT A WEAKENING TREND...SUGGESTING THIS DECK WILL BREAK
UP AND BECOME LESS ORGANIZED.
HAVE UPDATED THE FORECAST TO BRING IN THESE SCATTERED TO BROKEN
CLOUDS INTO MUCH OF EASTERN IA BY SUNRISE. EVEN SCATTERED CLOUDS
SHOULD LOWER THE POTENTIAL FOR FOG AND FROST AND HAVE REMOVED
MENTION IN THE FAR WEST...BUT WILL LEAVE IN OVER THE REMAINDER OF
THE FORECAST AREA WHERE THE TIMING SUGGESTS SKIES WILL BE AT
LEAST MOSTLY CLEAR THROUGH SUNRISE. WITH TEMPERATURES AND
DEWPOINTS RUNNING SIMILAR TO LAST NIGHT AT THIS TIME...FORECAST
MINS FROM THE UPPER 30S TO AROUND 40...WITH A FEW MID 30S IN
CENTRAL AND NORTHEAST VALLEYS...LOOK ON TRACK.
&&
.SYNOPSIS...
ISSUED AT 250 PM CDT SAT SEP 13 2014
LARGE AND SEASONABLY QUITE COOL EARLY FALL HIGH PRESSURE KEEPING
TEMPERATURES IN THE MID TO UPPER 50S WITH LIGHT WINDS AND JUST
ISOLATED CUMULUS CLOUDS. UPPER AIR ANALYSIS SHOWS NEXT SHORT WAVE
TO IMPACT REGION IS STILL 48 HOURS AWAY AND JUST ENTERING NW CONUS
WITH LIMITED MOISTURE SUGGESTING LIGHT RAIN AMOUNTS...IF ANY. LOTS
OF SW MONSOON MOISTURE WITH NEXT TROPICAL SYSTEM OFF MEXICO MAY
MAKE ITS WAY TOWARD AREA AGAIN...SIMILAR TO LAST EVENT...IN A WEEK
OR SO.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 250 PM CDT SAT SEP 13 2014
SHORT TERM FORECAST CONFIDENCE ASSESSMENT...ABOVE AVERAGE TO WELL
ABOVE AVERAGE OR GOOD TO EXCELLENT. LITTLE SENSIBLE WEATHER ISSUES
WITH CLEAR SKIES AND LIGHT WINDS. STRONG VERIFICATION OF PERSISTENCE
AND LOCAL TOOLS SUGGEST TEMPERATURES PROGGED PER LOCAL TOOLS SHOULD
BE WITHIN A DEGREE OR TWO FOR MOST AREAS NEXT 24 HOURS.
TONIGHT...FAIR SKIES AND LIGHT TO CALM WINDS TO ALLOW FOR BL DECOUPLING
WITH PATCHY FOG POSSIBLE TOWARD MORNING IN LOW LYING PLACES. MINS PER
LOCAL TOOLS HAVE LOWERED 1 TO 2 DEGREES WITH SOME PLACES POSSIBLY STILL
A DEGREE OR SO STILL TOO MILD. LOWS SHOULD BE CLOSE TO BREAKING OR
TYING LOW RECORDS AT BRL/MLI.
SUNDAY...ANOTHER FAIR AND SEASONABLY COOL DAY WITH SOME HIGH CLOUDS
AND FEW/SCT COVERAGE OF FAIR WEATHER CUMULUS CLOUDS MID DAY. HIGHS
WITH SOUTH WINDS OF 5 TO 10 MPH AND MODIFICATION SHOULD BE MOSTLY
IN THE MIDDLE 60S WITH SOME UPPER 60S SW SECTIONS. THESE TEMPERATURES
WILL STILL BE 10 DEGREES OR SO COOLER THAN NORMAL FOR MID SEPTEMBER.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 250 PM CDT SAT SEP 13 2014
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...
FORECAST FOCUS ON THE NEXT RAIN EVENT ON MONDAY FOLLOWED BY A MAINLY
DRY EXTENDED...WITH TEMPERATURES REMAINING BELOW NORMAL.
SUNDAY NIGHT THROUGH MONDAY NIGHT...SIGNIFICANT UPPER LEVEL TROUGH
WILL SWING ACROSS THE REGION IN THE NORTHWEST FLOW. MODERATE TO
STRONG VERTICAL MOTION IS FORECAST BY THE MODELS WHICH WILL SQUEEZE
OUT THE INCREASING PRECIPITABLE WATER. HAVE RAISED POPS INTO THE
LIKELY CATEGORY WITH ROOM TO RAISE THEM EVEN FURTHER. THE RAIN
SHOULD ARRIVE INTO EASTERN IA WELL AFTER MIDNIGHT SUNDAY NIGHT THEN
SPREAD OVER ALL THE CWA MONDAY MORNING. I WILL WALK OUT THE RAIN IN
OUR EASTERN CWA SOMETIME MONDAY EVENING. RAINFALL AMOUNTS SHOULD
RANGE FROM ABOUT 0.15 INCH IN THE NORTH...AROUND 2 TENTHS ALONG THE
I-80 CORRIDOR AND UP TO 1/2 INCH IN THE SOUTH.
TEMPERATURES ARE PROBLEMATIC ON MONDAY WITH AN ALL-DAY RAIN OVER
MOST OF THE CWA WITH 850 MB TEMPERATURES OF +6 TO 10C OVER THE CWA.
WHILE GUIDANCE INDICATES HIGHS IN THE LOWER TO MID 60S THIS SEEMS
TOO WARM BASED ON LOCAL TECHNIQUES...AND HAVE LOWERED READINGS TO
NEAR 60. THIS STILL MAY BE TOO WARM AND HIGHS IN THE 50S MAY BE MORE
REASONABLE WHERE THE RAIN PERSISTS ALL DAY.
TUESDAY THROUGH THURSDAY...HIGH PRESSURE WILL BE IN CONTROL WITH A
DRY NORTHWEST FLOW EXPECTED DURING THIS TIME FRAME. TEMPERATURES
SHOULD MODERATE DURING THE WEEK WITH HIGHS IN THE 60S TUESDAY
WARMING INTO THE LOWER TO MID 70S THURSDAY.
FRIDAY INTO NEXT WEEKEND...LOW CONFIDENCE AS ECMWF BRINGS A ZONAL
FLOW INTO THE MIDWEST WITH THE POTENTIAL FOR THUNDERSTORMS ON THE
EDGE OF A BUILDING HEAT DOME IN THE SOUTHERN PLAINS. THE GFS REMAINS
DRY WITH A SHARPENING TROUGH PUSHING INTO THE PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1149 PM CDT SAT SEP 13 2014
AN AXIS OF SCATTERED TO BROKEN CLOUDS AROUND 5000 T0 6000 FEET
MAY MOVE INTO ESPECIALLY THE CID...DBQ AND MLI BETWEEN 4 AND 9 AM.
OTHERWISE...DEPARTING HIGH PRESSURE OVER THE GREAT LAKES WILL
CONTINUE TO INFLUENCE THE AREA WITH LIGHT SE TO SOUTH WINDS
THROUGH SUNDAY. CONDITIONS WILL LIKELY REMAIN VFR WELL INTO SUNDAY
EVENING...WITH LOWERING CLOUDS AND THEN RAIN EXPECTED TO
OVERSPREAD THE AREA JUST BEYOND THE FORECAST PERIOD.
&&
.CLIMATE...
ISSUED AT 250 PM CDT SAT SEP 13 2014
RECORD LOWS FOR SEPTEMBER 14...
MOLINE.........39 IN 1974
CEDAR RAPIDS...36 IN 1929
DUBUQUE........34 IN 1974
BURLINGTON.....38 IN 1974
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...SHEETS
SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...HAASE
AVIATION...SHEETS
CLIMATE...NICHOLS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
457 AM EDT SUN SEP 14 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 457 AM EDT SUN SEP 14 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS SHORTWAVE/PV
ANOMALY UPSTREAM OVER NRN MN. PV ADVECTION AND 290-295K ISENTROPIC
ASCENT AHEAD OF THIS FEATURE HAS PRODUCED NARROW LINE OF SHRA FROM
WRN TIP OF LAKE SUPERIOR OVER THE MN ARROWHEAD EARLY THIS MORNING.
TODAY...MODEL CONSENSUS INDICATES SHORTWAVE WILL TRACK ACROSS NRN
LAKE SUPERIOR TODAY AND THEN EXIT NE OF THE LAKE LATE THIS
AFTERNOON. PV ADVECTION...ISENTROPIC ASCENT AND LOWERING
CONDENSATION PRES DEFICITS SUGGEST MUCH OF PCPN WITH THIS SYSTEM
WILL STAY ALONG AND NORTH OF PROJECTED VORT TRACK. WILL MAINTAIN
SLIGHT CHC TO LOW CHC POPS OVER MAINLY THE NRN TIER OF UPPER MI WITH
HIGHER CHC POPS OVER LAKE SUPERIOR TODAY ALONG/AHEAD OF COLD FRONTAL
PASSAGE. EXPECT HIGH TEMPS GENERALLY IN THE UPPER 50S TO LWR 60S.
TONIGHT...WITH SHORTWAVE AND ASSOC FORCING ALREADY NE OF LAKE
SUPERIOR...EXPECT SHRA OVER ERN COUNTIES TO DIMINISH QUICKLY THIS
EVENING ALONG FRONTAL BOUNDARY. WL MAINTAIN SLIGHT CHC POPS THIS
EVENING FOR ERN COUNTIES BUT OTHERWISE EXPECT DRYING/PARTIAL
CLEARING THIS EVENING FROM THE WEST BEHIND THE FRONT. EXPECT LOW
TEMPS TO RANGE IN THE UPPER 30S OVER MUCH OF THE WRN INTERIOR AND
THE TYPICAL COLD SPOTS OF THE ERN INTERIOR TO THE MID TO UPPER 40S
NEAR THE GREAT LAKES.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 401 AM EDT SUN SEP 14 2014
FOR MON...A SHORTWAVE LOOKS TO MOVE INTO THE UPPER TROUGH POSITIONED
OVER THE GREAT LAKES REGION...BUT THE SHORTWAVE WILL BE BEHIND A SFC
COLD FRONT THAT WILL MOVE THROUGH ABOUT 12 HOURS AHEAD ON SUN NIGHT.
GIVEN THAT THE BEST MOISTURE WILL BE ALONG AND AHEAD OF THE FRONT AS
A 1022MB SFC HIGH OVER THE PLAINS NOSES INTO THE REGION BEHIND THE
FRONT...WIDESPREAD PRECIP IS NOT EXPECTED ON MON. COULD SEE
SCATTERED SHOWERS AS THE SHORTWAVE PASSES OR RIGHT BEHIND THE
SHORTWAVE AS THE 850MB THERMAL TROUGH PASSES...WHICH MAY PROVIDE
SOME ADDITIONAL WEAK INSTABILITY. HIGH TEMPS WILL BE IN THE 50S.
THE UPPER TROUGH INTENSIFIES AND MOVES SLOWLY E THROUGH MID WEEK AS
THE UPPER RIDGE OVER THE WRN CONUS MOVES OVER THE ROCKIES. UPPER
LEVEL ENERGY TUE THROUGH THU WILL BE MAINLY N/NE OF THE CWA...BUT
SOME LOWER LEVEL FEATURES MAY LEAD TO SOME RAIN. MODELS GENERALLY
AGREE THAT A WEAK COLD FRONT WILL MOVE IN FROM THE N/NNE TUE NIGHT
AND THEN STALL OVER THE AREA WHILE DIMINISHING WED INTO THU. BEST
CHANCES FOR PRECIP DURING THIS TIME IS TUE NIGHT INTO WED SINCE A
SFC HIGH MOVES JUST N/NE OF THE CWA WED NIGHT INTO THU...RESULTING
IN A DRIER AIRMASS. ADDITIONALLY...THERE IS POTENTIAL FOR FRONT MON
NIGHT AND WED NIGHT.
THE PATTERN BECOMES MORE PROGRESSIVE FRI INTO SAT...WHICH MAY LEAD
TO A LOW PRESSURE SYSTEM OR JUST A TROUGH MOVING IN FROM THE W ON
SAT. THERE IS DISAGREEMENT BETWEEN MODELS FOR FRI AND SAT...WHICH IS
TO BE EXPECTED GIVEN THE MORE PROGRESSIVE/TRANSITIONAL FLOW. GENERAL
CONSENSUS DOES SHOW WAA FRI INTO EARLY SAT...BRINGING A WARMER
AIRMASS WITH 850MB TEMPS OF 13C-15C. PRECIP WILL BE POSSIBLE DURING
THIS TIME GIVEN THE WAA...POSSIBLE SHORTWAVE ENERGY HINTED AT BY
MODELS...AND THE ARRIVAL OF A SFC LOW OR TROUGH. DEPENDING ON AMOUNT
OF CLEARING...MAY SEE TEMPS TOP OUT IN THE 70S IN SPOTS BOTH
DAYS...BUT WILL LEAN MORE TOWARD COOLER CONSENSUS GUIDANCE GIVEN THE
CHANCES FOR PRECIP/CLOUD COVER...WHICH HAS HIGHS IN THE MID 60S TO
70.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 457 AM EDT SUN SEP 14 2014
UNDER RELATIVELY DRY LOW LEVELS...VFR CONDITIONS WILL PREVAIL THRU
THE FCST PERIOD AT KIWD/KCMX/KSAW. ON SUN...AN APPROACHING LOW PRES
TROF SHOULD BRING SCT -SHRA INTO NW UPPER MI BY AFTN. HAVE INCLUDED
A VCSH MENTION AT KCMX.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 457 AM EDT SUN SEP 14 2014
A LOW PRES TROF OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY AS
S TO SW WINDS OF 10-20 KT SHIFT WEST ACROSS THE LAKE. THERE MAY BE
PERIODS OF SOMEWHAT HIGHER WINDS TO 25 KTS LATE MON NIGHT THRU EARLY
WED AHEAD OF AND BEHIND A COLD FRONT THAT WILL DROP S ACROSS LAKE
SUPERIOR TUE. LIGHTER WINDS WILL THEN BE THE RULE LATER WED THRU THU
HAS HIGH PRES MOVE SE ACROSS NRN ONTARIO TOWARD THE LOWER LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...07
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
401 AM EDT SUN SEP 14 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 409 PM EDT SAT SEP 13 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW THE VIGOROUS SHORTWAVE
THAT PRODUCED PCPN OVER MUCH OF UPPER MI LAST NIGHT NOW MOVING THRU
SRN ONTARIO INTO QUEBEC. UPSTREAM...A PAIR OF SHORTWAVES ARE
NOTED...ONE OVER ND/SRN MANITOBA AND THE OTHER OVER SRN
SASKATCHEWAN. THESE WAVES WILL BRING THE NEXT PCPN CHC TO UPPER MI
ON SUNDAY. IN THE WAKE OF LAST NIGHTS SYSTEM...850MB TEMPS ARE
CURRENTLY -1 TO -2C OVER LAKE SUPERIOR. TYPICALLY AT THIS TIME OF
YEAR...THIS WOULD BE MORE THAN SUFFICIENT FOR LAKE EFFECT CLOUDS AND
PCPN. HOWEVER...WITH A LARGE PORTION OF LAKE SUPERIOR HAVING SFC
WATER TEMPS PROBABLY ONLY AROUND 7-9C...THERE WAS NOT MUCH IN THE
WAY OF LAKE EFFECT CLOUDS EARLIER TODAY. IN FACT...THE LAKE HAS
BEHAVED MOSTLY AS STABILIZING INFLUENCE. ONE BAND WITH A FEW
SPRINKLES DID STREAM INTO ERN MARQUETTE COUNTY BRIEFLY THIS MORNING
DUE TO LAND BREEZE CONVERGENCE AND WARMER WATER TO THE S AND E OF
THE KEWEENAW. THIS AFTN...DAYTIME HEATING/LOW-LEVEL CONVERGENCE AND
MOISTURE FROM THE LAKE RESULTED IN ADDITIONAL SPRINKLES DEVELOPING
IN ERN MARQUETTE COUNTY. THESE SPRINKLES ARE DRIFTING SE THRU DELTA
AND WRN ALGER COUNTIES. WHILE LAKE EFFECT CLOUDS WERE AT A MINIMUM
EARLIER TODAY...850MB THERMAL TROF COMBINED WITH ADDED MOISTURE FROM
THE LAKE RESULTED IN WIDESPREAD CU/STRATOCU DEVELOPING OVER THE LAND
ONCE DAYTIME HEATING BEGAN.
TONIGHT...MAIN FCST CONCERN IS FROST POTENTIAL. WHILE CU/STRATOCU IS
STILL QUITE EXTENSIVE...THE DIURNAL NATURE OF THE CLOUD DEVELOPMENT
SUGGESTS THE CLOUDS WILL DISSIPATE THIS EVENING WITH THE LOSS OF
DAYTIME HEATING. MEANWHILE...LEAD SHORTWAVE TO THE W IS GENERATING A
FAIR AMOUNT OF HIGH CLOUDINESS WHICH WILL STREAM OVER THE FCST AREA
AS THE WAVE MOVES OVER THE UPPER LAKES. DISSIPATING STRATOCU THIS
EVENING BEING REPLACED BY HIGH CLOUDS WILL BE ONE FACTOR HELPING TO
KEEP TEMPS FROM CRASHING. OTHER FACTOR WILL BE DEPARTURE OF HIGH
PRES RIDGE CURRENTLY OVER THE AREA. AS PRES GRADIENT TIGHTENS BTWN
THE EXITING HIGH AND APPROACHING SFC TROF... THERE WILL BE SOME
INCREASE IN MIXING. THAT SAID...THE INITIAL DRY AIR MASS
(PRECIPITABLE WATER 45-55PCT OF NORMAL) AND LIGHT WINDS OVER THE
AREA WILL STILL ALLOW TEMPS TO FALL INTO THE MID 30S AND TO EVEN THE
LOWER 30S IN TRADITIONAL COLD SPOTS. SO...FCST WILL SHOW PATCHY
FROST OVER MUCH OF THE INTERIOR. AT THIS POINT...NOT EXPECTING
COVERAGE TO BE LARGE ENOUGH TO WARRANT A FROST ADVY. EVENING SHIFT
WILL NEED TO MONITOR CLOUD TRENDS AND TEMPS TO RE-EXAMINE THE NEED
FOR HEADLINE ISSUANCE BY LATE EVENING.
ON SUN...SECOND SHORTWAVE WILL SWING ACROSS THE UPPER GREAT LAKES.
AS IN PREVIOUS DAYS...MODELS CONTINUE TO INDICATE BEST
MOISTURE/FORCING PASSING JUST N OF THE AREA...ALONG AND N OF
PROJECTED VORT TRACK. SEE NO REASON TO DEVIATE MUCH FROM PREVIOUS
FCST WITH MAINLY CHC POPS SPREADING INTO WRN UPPER MI IN THE MID TO
LATE MORNING AND THEN REACHING THE E MID TO LATE AFTN. EXPECT HIGH
TEMPS GENERALLY IN THE UPPER 50S TO LWR 60S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 401 AM EDT SUN SEP 14 2014
FOR MON...A SHORTWAVE LOOKS TO MOVE INTO THE UPPER TROUGH POSITIONED
OVER THE GREAT LAKES REGION...BUT THE SHORTWAVE WILL BE BEHIND A SFC
COLD FRONT THAT WILL MOVE THROUGH ABOUT 12 HOURS AHEAD ON SUN NIGHT.
GIVEN THAT THE BEST MOISTURE WILL BE ALONG AND AHEAD OF THE FRONT AS
A 1022MB SFC HIGH OVER THE PLAINS NOSES INTO THE REGION BEHIND THE
FRONT...WIDESPREAD PRECIP IS NOT EXPECTED ON MON. COULD SEE
SCATTERED SHOWERS AS THE SHORTWAVE PASSES OR RIGHT BEHIND THE
SHORTWAVE AS THE 850MB THERMAL TROUGH PASSES...WHICH MAY PROVIDE
SOME ADDITIONAL WEAK INSTABILITY. HIGH TEMPS WILL BE IN THE 50S.
THE UPPER TROUGH INTENSIFIES AND MOVES SLOWLY E THROUGH MID WEEK AS
THE UPPER RIDGE OVER THE WRN CONUS MOVES OVER THE ROCKIES. UPPER
LEVEL ENERGY TUE THROUGH THU WILL BE MAINLY N/NE OF THE CWA...BUT
SOME LOWER LEVEL FEATURES MAY LEAD TO SOME RAIN. MODELS GENERALLY
AGREE THAT A WEAK COLD FRONT WILL MOVE IN FROM THE N/NNE TUE NIGHT
AND THEN STALL OVER THE AREA WHILE DIMINISHING WED INTO THU. BEST
CHANCES FOR PRECIP DURING THIS TIME IS TUE NIGHT INTO WED SINCE A
SFC HIGH MOVES JUST N/NE OF THE CWA WED NIGHT INTO THU...RESULTING
IN A DRIER AIRMASS. ADDITIONALLY...THERE IS POTENTIAL FOR FRONT MON
NIGHT AND WED NIGHT.
THE PATTERN BECOMES MORE PROGRESSIVE FRI INTO SAT...WHICH MAY LEAD
TO A LOW PRESSURE SYSTEM OR JUST A TROUGH MOVING IN FROM THE W ON
SAT. THERE IS DISAGREEMENT BETWEEN MODELS FOR FRI AND SAT...WHICH IS
TO BE EXPECTED GIVEN THE MORE PROGRESSIVE/TRANSITIONAL FLOW. GENERAL
CONSENSUS DOES SHOW WAA FRI INTO EARLY SAT...BRINGING A WARMER
AIRMASS WITH 850MB TEMPS OF 13C-15C. PRECIP WILL BE POSSIBLE DURING
THIS TIME GIVEN THE WAA...POSSIBLE SHORTWAVE ENERGY HINTED AT BY
MODELS...AND THE ARRIVAL OF A SFC LOW OR TROUGH. DEPENDING ON AMOUNT
OF CLEARING...MAY SEE TEMPS TOP OUT IN THE 70S IN SPOTS BOTH
DAYS...BUT WILL LEAN MORE TOWARD COOLER CONSENSUS GUIDANCE GIVEN THE
CHANCES FOR PRECIP/CLOUD COVER...WHICH HAS HIGHS IN THE MID 60S TO
70.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 715 PM EDT SAT SEP 13 2014
UNDER RELATIVELY DRY LOW LEVELS...VFR CONDITIONS WILL PREVAIL THRU
THE FCST PERIOD AT KIWD/KCMX/KSAW. ON SUN...AN APPROACHING LOW PRES
TROF SHOULD BRING SCT -SHRA INTO NW UPPER MI BY AFTN. HAVE INCLUDED
A VCSH MENTION AT KCMX.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 409 PM EDT SAT SEP 13 2014
APPROACHING LOW PRES TROF WILL RESULT IN INCREASING S TO SW WINDS
TONIGHT INTO SUN. WHILE LOWER OBS PLATFORMS SHOULDN`T SEE WINDS
GREATER THAN THE 10-20KT RANGE...HIGH OBS PLATFORMS WILL PROBABLY
SEE GUSTS TO AROUND 25KT. WINDS SHOULD FALL BACK TO MOSTLY 10-20KT
SUN NIGHT THRU MON. THERE MAY BE SOMEWHAT HIGHER WINDS AGAIN LATE
MON NIGHT THRU EARLY WED AHEAD OF AND BEHIND A COLD FRONT THAT WILL
DROP S ACROSS LAKE SUPERIOR TUE. LIGHTER WINDS WILL THEN BE THE RULE
LATER WED THRU THU HAS HIGH PRES MOVE SE ACROSS NRN ONTARIO TOWARD
THE LOWER LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...TITUS
AVIATION...07
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
342 AM CDT SUN SEP 14 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CDT SUN SEP 14 2014
MAIN UPPER PV ANOMALY LOCATED ACROSS NRN ND WILL CONTINUE ITS QUICK
EWD PROGRESSION TO THE NRN GREAT LAKES REGION THROUGH THE DAY WHILE
ASSOCIATED FRONT LOSES SWD MOMENTUM AND IS PROGGED BY THE MODELS TO
STALL ACROSS NRN NEB. THIS IS IN LINE WITH CURRENT PRESSURE FIELDS
EARLY THIS MORNING AS BEST FALLS ARE OVER NRN MN AND WEAK RISES
BEHIND THE FRONT AS IT ENTERS THE NRN PORTION OF THE STATE. UNDULAR
BORE EVIDENT WITH THE FRONT CURRENTLY ON KLNX 88D INDICATING STABLE
LOW LEVELS...HOWEVER RAP ANALYSIS AND IR IMAGERY SUGGEST SMALL AREA
OF WEAK MID LEVEL FRONTOGENESIS INDICATIVE OF DEVELOPING WARM AIR
ADVECTION ACROSS NWRN FCST AREA CURRENTLY AND LIKELY TAPPING WEAK
INSTABILITY BASED ON CONVECTIVE NATURE TO CLOUDS...AND ECHOES
SHOWING UP ALOFT ON KLNX 88D. FOR THE REST OF THE AREA...VERY LITTLE
IN THE WAY OF CLOUDS ASSOCIATED WITH THE FRONT WHICH IS EVIDENCE OF
ITS KATABATIC NATURE WITH 0.5KM/1KM AND 700 MB VWP WINDS FROM AREA
RADARS AND RAP SHORT TERM FCST SOUNDINGS SHOWING NWRLY WINDS AHEAD
OF THE FRONT. HAVE INCLUDED SPRINKLES EARLY THIS MORNING BASED ON
RADAR TRENDS MENTIONED ABOVE.
AS UPPER PV ANOMALY AND ASSOCIATED UPPER LOW MOVES INTO NRN MN THIS
MORNING...MID AND UPPER FLOW BECOMES ZONAL ACROSS THE CENTRAL
ROCKIES AND HIGH PLAINS. IN RESPONSE...MID LEVEL WINDS BECOME SWRLY
WHICH WILL ADVECT THE EML EWD OVER THE EWD ADVANCING DRYLINE ACROSS
ERN CO...AS LOWER LEVEL WINDS BACK AND BECOME S/SERLY DURING THE
AFTERNOON. NAM PROGS SFC DEW POINTS INTO THE MID 50S ACROSS SWRN
NEB...HOWEVER THE AFOREMENTIONED EML DEVELOPS A SIGNIFICANT CAP EAST
OF THE DRYLINE IN SWRN NEB DURING THE AFTERNOON HOURS. SCT/BKN CLOUD
COVER IS EXPECTED EAST OF THE DRYLINE AS WELL WHICH WILL BE EVIDENCE
OF THE HIGHER LOW LEVEL THETA E AND HIGHER CAPE. HOWEVER...DESPITE
THE NEXT APPROACHING UPPER PV ANOMALY AND STALLED SFC BOUNDARY
ACROSS THE NRN PORTION OF THE STATE...AND THE PREVIOUSLY MENTION
HIGHER CAPE AND DECENT SHEAR...THE CAP IS EXPECTED TO BE TOO STRONG
TO ALLOW CONVECTIVE INITIATION DURING THE AFTERNOON IN WRN NEB.
HOWEVER...CONVECTION ALLOWING MODELS /CAMS/ ARE QUICKER TO DEVELOP
STORMS ACROSS NRN NEB INTO SERN SD BY EVENING WHICH WILL BE CLOSER
TO MAIN UPPER LEVEL SUPPORT AND SFC WARM FRONT SO PRECIP CHANCES
WILL BE RETAINED IN THE NERN PORTION OF THE FCST AREA...THOUGH MAY
BE PUSHED BACK IN TIME A LITTLE.
NEXT SIGNIFICANT UPPER PV ANOMALY AND ASSOCIATED UPPER LOW WILL MOVE
INTO THE NRN PLAINS THIS EVENING AND SUNDAY NIGHT. THIS WILL GIVE A
NUDGE TO THE STALLED SFC BOUNDARY AND WILL MOVE IT SWD
SOMEWHAT...BUT THE HIGH PLAINS NOCTURNAL LOW LEVEL JET WILL DEVELOP
AS DRIER AIR ACROSS THE HIGHER ELEVATIONS FURTHER WEST COOLS RAPIDLY
AFTER SUNSET...BUT ALSO PARTLY IN RESPONSE TO THE LOWERING HEIGHTS
ACROSS THE NRN PLAINS. THIS LIFT WILL BE ABLE TO TAP THE ELEVATED
INSTABILITY STILL RESIDING ACROSS SWRN NEBR TO DEVELOP THUNDERSTORMS
OVERNIGHT SUNDAY NIGHT AS THE FRONT SLOWLY CONTINUES TO SAG ACROSS
THE REMAINDER OF THE STATE. THOUGH THE NAM SUPPORTS PRECIP IN THE
SWRN PORTION OF THE STATE OVERNIGHT...CAMS FOCUS MOST OF THE PRECIP
ALONG THE COLD FRONT IN NRN NEB.
AS FOR TEMPERATURES...DESPITE DEVELOPING CLOUD COVER DURING THE
AFTERNOON IN THE SW...TEMPS WILL BE MUCH WARMER WITH INCREASING SRLY
WINDS BUT WILL BE SLIGHTLY COOLER ACROSS THE NORTH AS WINDS BECOME
ERLY NORTH OF THE WARM FRONT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 342 AM CDT SUN SEP 14 2014
QUASI-ZONAL UPPER TROPOSPHERIC FLOW TO PREVAIL BEHIND A PASSING
NORTHERN PLAINS WAVE EARLY IN THE EXTENDED...BUT WILL EVENTUALLY
GIVE WAY TO NORTHWESTERLY AS A WESTERN CONUS RIDGE BUILDS EAST. AS
A RESULT A GENERAL LACK OF OMEGA IS ANTICIPATED ATOP MUCH OF THE
FORECAST AREA THROUGH TUESDAY AFTERNOON...WITH THE MODELS
PROJECTING NO ATMOSPHERIC DISTURBANCES IMPACTING THE REGION.
TUESDAY EVENING INTO WEDNESDAY...THE OPERATIONAL MODELS /GFS
INITIALLY...THEN ECMWF WEDNESDAY MORNING/ GENERATES MEASURABLE QPF
ACROSS SOUTHEASTERN PORTIONS OF THE CWA...THE MODELS ARE KEYING ON
SUFFICIENT THERMAL ADVECTION/UPGLIDE IN THE 305-310K SFC FOR
PRECIPITATION PRODUCTION. DESPITE THIS...DECIDED TO LEAVE QPF OUT
OF THE FORECAST AS PROXIMITY AND BUFR SOUNDINGS SUGGEST A MOISTURE
CHALLENGED ATMOSPHERE ABOVE THE BOUNDARY LAYER WITH THE GFS
SHOWING SIGNIFICANT DRY MID LEVELS. WITH THIS IN MIND...FELT THAT
POPS WILL BE ISOLATED AT BEST IN COVERAGE WITH QPF AMOUNTS LIGHT.
IF SHOWERS/STORMS ARE TO GO...SOUTHEASTERN PORTIONS OF THE CWA
OVERNIGHT TUESDAY INTO EARLY WEDNESDAY WOULD BE THE MOST LIKELY OF
LOCATIONS. ADDITIONAL THERMAL ADVECTION INDUCED STORMS ARE SHOWN
WEDNESDAY NIGHT INTO THURSDAY...BUT MOSTLY REMOVED /SOUTH AND
EAST/ FROM OUR CWA. CR ALLBLEND PULLED ALL MENTION OF QPF OUT OF
OUR CWA DURING THIS TIME PERIOD...WHICH IS FINE FOR NOW. UPPER
PATTERN UNDERGOES A CHANGE LATE IN THE WEEK WITH THE APPROACH OF A
WESTERN CONUS TROUGH AND ATTENDANT COLD FRONT PASSAGE. THE
TROUGH/COLD FRONT WILL SUPPRESS THE RIDGE EAST OF THE FORECAST
AREA LATE WEEK AND PROVIDE FOR PRECIPITATION. THE GFS IN
COMPARISON TO THE EC REMAINS MUCH STRONGER WITH THIS LATE WEEK
TROUGH AND MORE FAVORABLE FOR WIDESPREAD SHOWERS/STORMS. THE CR
ALLBLEND PROCEDURE RAMPS UP POPS STARTING FRIDAY...WITH POPS
MAXIMIZED NEAR 40 PERCENT FOR SATURDAY AND INTO EARLY SUNDAY. TO
BE HONEST...REALLY NOT TOO KEEN ON 4 PERIODS OF QPF THAT IS
ASSOCIATED WITH THE PASSAGE OF THIS DISTURBANCE/FRONT...ESPECIALLY
IN A SOMEWHAT PROGRESSIVE PATTERN...BUT WILL LEAVE THE PROCEDURE
UNCHANGED DUE TO THE USUAL TIMING/STRENGTH DIFFERENCES SEEN THIS
FAR OUT.
DRIZZLE REPLACED THE SLIGHT CHANCE MENTION OF QPF FROM 12-15Z THIS
MONDAY AS PROXIMITY SOUNDINGS REVEAL DRYING ALOFT...BUT A SATURATED
BL WITH WEAK LIFT. THIS DRIZZLE SHOULD NOT LAST LONG AS PROXIMITY
SOUNDINGS REVEAL RAPID BL DRYING BEHIND THE FRONT. WILL ALSO NEED
TO MONITOR THE RETURN OF LOW LEVEL MOISTURE EARLY TUESDAY AS SURFACE
HIGH PRESSURE BUILDS EAST OF THE MISSOURI VALLEY. NAM12 0.5AGL RH
WOULD INDICATE A SIGHT POTENTIAL OF FOG ACROSS SOUTHWEST
NEBRASKA...BUT CONFIDENCE WAS NOT SUFFICIENT TO INCLUDE THE MENTION
WITH THIS FORECAST.
RETURN SOUTHERLY FLOW AND RESULTANT THERMAL ADVECTION WILL PROMOTE A
WARMING TREND MONDAY THROUGH MID-LATE WEEK...WIDESPREAD HIGHS IN THE
80S BY THURSDAY ARE ANTICIPATED. WARMEST READINGS WILL BE ACROSS
OUR WEST EACH DAY WITH A GREATER INFLUENCE FROM THE UPPER TROPOSPHERIC
RIDGE. OVERNIGHT LOWS WILL BENEFIT AS WELL...RISING FROM THE 40S
MONDAY MORNING...TO POSSIBLY THE 50S TO 60S BY WEEKS END.
TEMPERATURES COOL LATE WEEK BEHIND THE FRONT...BUT AT THAT...NOT
ANTICIPATING WHAT WE SAW A FEW DAYS AGO...NO FROST OR FREEZE
ISSUES ARE EXPECTED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1230 AM CDT SUN SEP 14 2014
VISUAL FLIGHT RULES REST OF TONIGHT INTO SUNDAY AT THE KLBF AND
KVTN TERMINALS. MODELS ARE IN GOOD AGREEMENT...WHERE A WEAK
SURFACE BOUNDARY MOVES SOUTH TONIGHT THEN RETURNS NORTH ACROSS
SOUTHWEST NEBRASKA BY LATE SUNDAY AFTERNOON AS A WARM FRONT. FEW
CLOUDS WILL BE SEEN UNTIL LATE AFTERNOON AS MOISTURE SLOWLY
RETURNS ACROSS THE SOUTHWEST. ISOLATED SHOWERS AND/OR
THUNDERSTORMS MAY DEVELOP AS INSTABILITY INCREASES WITH SURFACE
HEATINGS...BUT LOW CONFIDENCE AT THIS TIME.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JWS
LONG TERM...JACOBS
AVIATION...KECK/JWS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1212 AM CDT SUN SEP 14 2014
.UPDATE...
ISSUED AT 1209 AM CDT SUN SEP 14 2014
MADE ONLY MINOR ADJUSTMENTS TO THE FORECAST FOR THIS UPDATE. EARLY
MORNING 11-3.9 MICRON SATELLITE IMAGERY SHOWS STRATUS MOVING
SOUTHEAST INTO NORTH CENTRAL NORTH DAKOTA. THE 14.00Z NAM SUGGESTS
THE CLOUDS MAY LINGER A BIT LONGER TODAY (SUNDAY) IN THE NORTHEAST
PORTION OF THE FORECAST AREA...SO STARTED THAT TREND IN THIS
UPDATE. THE FROST ADVISORY STILL LOOKS GOOD SO LEFT IT IN PLACE.
UPDATE ISSUED AT 951 PM CDT SAT SEP 13 2014
NO SIGNIFICANT CHANGES REQUIRED WITH THIS UPDATE. DECIDED TO NOT
EXPAND THE FROST ADVISORY AS THE LOWEST DEW POINTS IN THE MID 30S
AS OF 0230 UTC RESIDE WITHIN THE CURRENT ADVISORY...WITH WINDS
EXPECTED TO BECOME CALM AS THE SURFACE RIDGE AXIS PROPAGATES INTO
WESTERN NORTH DAKOTA. ELSEWHERE OUTSIDE OF THE
ADVISORY...RELATIVELY GREATER LOW LEVEL MOISTURE...STRONGER WINDS
AND GREATER CLOUD COVER SHOULD KEEP TEMPERATURES WARM ENOUGH TO
PREVENT WIDESPREAD FROST.
UPDATE ISSUED AT 652 PM CDT SAT SEP 13 2014
NO CHANGES PLANNED AT THIS TIME IN REGARDS TO THE FROST ADVISORY
FOR TONIGHT...WHICH IS IN LINE WITH THE 18 UTC NAM/GFS/MAV. WILL
CONTINUE TO MONITOR CLOUD TRENDS THROUGH EVENING SHOULD A SMALL
EXPANSION OF THE ADVISORY BE NECESSARY.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 329 PM CDT SAT SEP 13 2014
COLD FRONT MOVING THROUGH THE REGION WILL GENERATE WIDELY
SCATTERED SHOWERS ACROSS NORTHERN NORTH DAKOTA THIS AFTERNOON AND
EARLY THIS EVENING. GENERALLY FOLLOWED THE HRRR IN AREA AND TIMING
OF THE SHOWERS. SHOWERS WILL END BEFORE MIDNIGHT. SKIES WILL CLEAR
WITH OVERNIGHT LOWS IN THE LOWER TO MIDDLE 30S WEST. ISSUED A
FROST ADVISORY ACROSS THE WEST...GENERALLY WEST OF THE MISSOURI
RIVER AND WEST OF MINOT. SURFACE HIGH PRESSURE WILL COVER THE
REGION SUNDAY AND ANOTHER ROUND OF PATCH FROST IS POSSIBLE SUNDAY
NIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 329 PM CDT SAT SEP 13 2014
THE EXTENDED PERIOD WILL REMAIN LARGELY DRY THROUGH THURSDAY AS A
LARGE UPPER LOW ACROSS EASTERN CANADA SLOWLY MOVES EAST. AS THIS
HAPPENS BROAD RIDGING WILL DEVELOP OVER THE CENTRAL AND NORTHERN
PLAINS. THIS WILL ALLOW A SLOW WARMING TREND THROUGH THE MIDDLE TO
AND OF NEXT WEEK. BY NEXT WEEKEND A COLD FRONT WILL MOVE THROUGH
BRINGING SCATTERED THUNDERSTORMS TO THE REGION THURSDAY NIGHT INTO
FRIDAY NIGHT.
FOR TEMPERATURES...SUNDAY NIGHT COULD SEE SOME SCATTERED FROST
BEFORE THE WARM UP BEGINS. OTHER THAN THAT...MORNING LOWS WILL B IN
THE 40S TO MIDDLE 50S WITH HIGHS IN THE 60S MONDAY AND THE 70S TO
AROUND 80 TUESDAY THROUGH SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1209 AM CDT SUN SEP 14 2014
MVFR CEILINGS ARE POSSIBLE AT KMOT EARLY THIS SUNDAY MORNING AS
THEY PIVOT IN BEHIND A DEPARTING AREA OF SURFACE LOW PRESSURE.
WILL KEEP THE OTHER TERMINAL LOCATIONS VFR...THOUGH KJMS WILL HAVE
TO BE MONITORED SINCE IT APPEARS THE MVFR STRATUS MAY APPROACH
THAT AREA LATER TODAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY UNTIL 9 AM CDT /8 AM MDT/ THIS MORNING FOR NDZ001-
002-009-010-017>021-031>034-040>045.
&&
$$
UPDATE...CK
SHORT TERM...WAA
LONG TERM...WAA
AVIATION...CK
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
1135 AM EDT SUN SEP 14 2014
.UPDATE...
A SLIVER OF DRIER AIR HAS MOVED THROUGH THE AREA THIS MORNING ON
THE EDGE OF AN UPPER LEVEL JET SETTLING SOUTH ACROSS THE
PENINSULA. THE JET SHOULD SLIP SOUTH ACROSS A FORT MYERS TO FORT
PIERCE LINE...PUSHING THE DRIER AIR SOUTH INTO THE FLORIDA
STRAITS. THIS SHOULD ALLOW MOISTURE TO RETURN OVER WEST CENTRAL
AND SOUTHWEST FLORIDA LATER TODAY WHICH WILL COMBINE WITH A GULF
COAST SEA BREEZE AND DIURNAL HEATING TO PRODUCE SHOWERS AND
THUNDERSTORMS THIS AFTERNOON AND EVENING.
AN OUTFLOW FROM EARLIER CONVECTION NEAR THE KEYS HAS MADE ITS WAY
INTO THE WATERS OFF SOUTHWEST FLORIDA AND WILL SOON COME ASHORE.
HAVE ADJUSTED POPS OFF THE OBSERVED TRENDS ALONG WITH NEW HRRR AND
LOCAL CAM GUIDANCE RUNS. UPDATED ZONES HAVE ALREADY BEEN
SENT...EXPECT A LATE START TO DIURNAL CONVECTION AGAIN TODAY WITH
ACTIVITY FORMING INLAND AND ALONG THE SEA BREEZE AS IT PUSHES IN
ALONG THE INTERSTATE 75 CORRIDOR. THE SOUTHEASTERLY FLOW WILL THEN
PUSH THE CONVECTION TO THE NORTHWEST. THE FLOW SHOULD PROMOTE
QUICK STORM MOVEMENT...THOUGH SOME AREAS COULD SEE NUISANCE
FLOODING FROM SEVERAL STORMS AND TRAINING OF STORMS OVER THE SAME
AREA. GUSTY WINDS AND LIGHTNING ARE THE PRIMARY CONCERNS WITH
CONVECTION TODAY. AFTER SUNSET...THE REMAINING ACTIVITY SHOULD
PUSH OFFSHORE AND DIMINISH OVER LAND.
&&
.AVIATION...
VFR EXPECTED THROUGH THE PERIOD...THOUGH BRIEF MVFR/IFR POSSIBLE
WITH STORMS TODAY. SOUTHEAST FLOW AROUND 10 KNOTS TODAY...WITH
GUSTY VARIABILITY AROUND CONVECTION. TIMING OF CONVECTION START THIS
AFTERNOON FROM AROUND 17Z-18Z IN SW FLORIDA TO 20-21Z AROUND THE
TAMPA BAY AREA TERMINALS. CONVECTION SHOULD DIMINISH FROM SOUTH TO
NORTH SIMILARLY...BETWEEN 00Z TO 04Z.
&&
.MARINE...
A RIDGE OF HIGH PRESSURE NORTH OF THE WATERS TODAY WILL BEGIN TO
WEAKEN AND SLIP SOUTH INTO THE COASTAL WATERS MONDAY AND TUESDAY. A
WEAK COLD FRONT WILL APPROACH THE NORTHEAST GULF TUESDAY NIGHT THEN
MOVE VERY SLOWLY SOUTHWARD THROUGH THE WATERS WEDNESDAY AND
THURSDAY. SEAS MAY BE AS HIGH AS 3 FEET WELL OFFSHORE EARLY
TODAY...BUT THE OVERALL TREND WILL BE FOR DECREASING WINDS AND SEAS
OVER THE NEXT COUPLE OF DAYS AS THE RIDGE SETTLES IN OVER FLORIDA.
AFTER THAT...SOME WESTERLY FLOW WILL DEVELOP AHEAD OF THE WEAK
FRONTAL BOUNDARY TOWARD THE MIDDLE OF THE WEEK...BUT AT THIS TIME WE
DO NOT EXPECT WINDS AND SEAS TO INCREASE SIGNIFICANTLY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 91 76 91 77 / 60 40 40 30
FMY 91 73 92 75 / 70 30 60 30
GIF 92 74 92 74 / 50 40 50 30
SRQ 91 74 91 76 / 60 40 40 30
BKV 92 71 92 71 / 50 40 50 40
SPG 90 78 90 79 / 60 40 40 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/AVIATION...02/GARCIA
MARINE...63/JILLSON
DECISION SUPPORT...57/MCMICHAEL
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1020 AM EDT SUN SEP 14 2014
.DISCUSSION...
.UPDATE...10Z CAPE SOUNDING INDICATED PRECIPITABLE WATER VALUES NEAR
1.8 INCHES WITH LOW LVL S/SE FLOW BACKING TO THE E/ENE ABOVE 700 MBS
WITH 40-45 KNOTS OF NE UPPER LEVEL WINDS ABOVE 300 MBS. GPS PRECIP
WATER VALUES HAVE BEEN TRENDING DOWN THIS MORNING WITH READING OF
1.67 AT THE CAPE AT 1145Z...1.65 AT OKEECHOBEE...1.45 AT BARTOW AND
1.48 INCHES IN GAINESVILLE. MODELS INDICATE ADDITIONAL DRYING IN THE
H7-H5 LAYER AND ALSO ALOFT FROM THE E AND NE WHICH SHOULD ACT TO
LIMIT COVERAGE OF SHOWER AND THUNDERSTORMS. 10 AM SFC DWPTS RANGED
FROM 68 DEGS AT KFPR AND KSUA TO THE LOWER 70S ACROSS NRN AREAS.
WATER VAPOR IMAGERY SHOWS SOME VERY DRY AIR ALOFT ACROSS MARTIN
COUNTY AND THE LAKE OKEECHOBEE REGION WITH SOME LARGE SCALE
SUBSIDENCE LIKELY ALONG THE NOSE OF AN 250 MB JET STREAK. THE SHORT
RANGE MESOSCALE RUNS FROM THE HRRR ARE ALSO NOT THAT ROBUST WITH
CONVECTION SHOWING MAINLY SHOWERS DEVELOPING OVER THE INTERIOR THIS
AFTERNOON AND MOVING WESTWARD INTO THE LATE AFTERNOON AND EARLY
EVENING. WILL BE ABLE TO LOWER POPS ALONG THE COAST IN THIS REGIME
TO AROUND 20 PCT AND WILL PROBABLY CONTINUE WITH 30-40 PCT RAIN
CHANCES FOR INTERIOR AREAS. HIGHS EXPECTED IN THE UPPER 80S COAST TO
AROUND 90 TO THE LOWER 90S ACROSS THE INTERIOR.
&&
.AVIATION...SHOULD SEE ISOLD-SCT SHRA/TSRA DVLP ACROSS INTERIOR
AREAS THIS AFTERNOON AND MOVE WESTWARD. CHCS DO NOT LOOK HIGH ENOUGH
TO HAVE MORE THAN VC IN TERMINALS AT THIS TIME.
&&
.MARINE...
SE WINDS 5 TO 10 KNOTS WITH SEAS AROUND 2 FT ACROSS THE WATERS WITH
ONLY ISOLATED SHOWERS/THUNDERSTORMS AT BEST. FORECAST ON TRACK.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
VOLKMER/SEDLOCK
AREA FORECAST DISCUSSION
NWS MIAMI FL
756 AM EDT SUN SEP 14 2014
.AVIATION...
EASTERLY FLOW CONTINUES TODAY, HOWEVER RELATIVELY MID LEVEL DRIER
AIR ARRIVING THIS AFTERNOON, AS SEEN ON CURRENT WATER VAPOR IMAGES
SHOULD KEEP PRECIP CHANCES LOW AND THUNDERSTORMS WIDELY SCATTERED
KTMB/KOPF/KMIA. AGAIN, EXPECTING BEST COVERAGE OF SHOWERS AND
STORMS TO BE ACROSS INLAND SECTIONS AND WEST COAST. GUIDANCE HAS
BACKED OFF A BIT WITH REGARDS TO A GULF BREEZE DEVELOPING AT KAPF
THIS PM, BUT STORMS PROGRESSING ACROSS THE PENINSULA SHOULD
EVENTUALLY AFFECT THAT TERMINAL. SOME MVFR/IFR CONDS POSSIBLE
WITH TEMPO GROUPS NECESSARY THIS PM AT KAPF. ELSEWHERE, CAN`T
RULE OUT SOME SHOWERS MAINLY THIS MORNING DEVELOPING ALONG THE
IMMEDIATE EAST COAST, OR ARRIVING FROM OFFSHORE BUT WILL NOT BE
INCLUDING ANY VCTS AT THIS TIME FOR AFTERNOON STORMS, AS MOST EAST
COAST TERMINALS SHOULD BE BEHIND THE SEA BREEZE BOUNDARY. ENOUGH
MID LEVEL DRIER AIR MAY REMAIN TONIGHT TO BREAK THE STRING OF WET
AND STORMY OVERNIGHTS.
&&
.PREV DISCUSSION... /ISSUED 402 AM EDT SUN SEP 14 2014/
SHORT TERM...(TODAY-TUESDAY)
THE EARLY MORNING SURFACE ANALYSIS SHOWED SOUTHEAST FLOW ACROSS THE
LOCAL AREA WITH A WEAK FRONTAL BOUNDARY EXTENDING SW ACROSS THE
REGION TO THE NORTH AND A WEAK TROUGH OF LOW PRESSURE CENTERED OVER
THE CENTRAL GULF OF MEXICO. THE LATEST WATER VAPOR LOOP SHOWED A
COMPLEX MID/UPPER LEVEL PATTERN ACROSS THE REGION CHARACTERIZED WITH
A RIDGE AXIS ORIENTED FROM EAST TO WEST OVER THE NORTHERN GULF COAST
STATES AND TWO UPPER LOWS EAST AND WEST OF THE FLORIDA PENINSULA.
PLENTY OF MID-UPPER MOISTURE CONTINUES TO LIFT NORTH OVER THE AREA
EAST OF THE UPPER LOW OVER THE GULF OF MEXICO...WHICH SUPPORTS THE
WIDESPREAD SHOWER ACTIVITY OVER THE ATLANTIC AND EAST COAST
LOCATIONS THIS MORNING. THE LATEST HRRR MODEL RUN HAS INITIALIZED
WELL WITH THIS ACTIVITY AND GENERALLY INDICATES A LARGE SHIELD OF
MAINLY LIGHT TO MODERATE RAIN REMAINING POSSIBLE THROUGH THE MID-
MORNING HOURS BEFORE DIMINISHING. LATER THIS AFTERNOON THE LATEST
MODEL SOUNDINGS INDICATE SOME DRIER AIR FILLING IN FROM THE
SOUTHEAST WITH PWATS DROPPING TOWARD 1.6" OVER THE SE FLORIDA
COAST AND INCREASING TO OVER THE 2" MARK BETWEEN NAPLES AND THE
LAKE LATER TODAY. THIS GRADIENT WILL BE REFLECTED IN THE LATEST
FORECAST PACKAGE SHOWING THE GREATEST RAINFALL CHANCES ALONG THE
SOUTHEAST FLORIDA COAST THROUGH THE MORNING HOURS AND ACROSS THE
INTERIOR AND LAKE REGION LATER THIS AFTERNOON THROUGH THIS
EVENING. MONDAY THROUGH TUESDAY...CONDITIONS ARE EXPECTED TO TREND
BACK TOWARD NORMAL AS SOME ADDITIONAL MID-LEVEL DRY AIR MOVES INTO
THE AREA. EASTERLY LOW-LEVEL FLOW UP TO 700 MB WILL PERSIST
THROUGH THIS TIME...WHICH WILL KEEP THE DIURNALLY DRIVEN
CONVECTIVE ACTIVITY FOCUSED INLAND AND TOWARD THE GULF COAST EACH
AFTERNOON/EVENING.
/85
LONG TERM (WEDNESDAY-FRIDAY)...
THE LATEST EXTENDED GUIDANCE REMAINS IN DECENT AGREEMENT AND
GENERALLY INDICATES FALLING UPPER HEIGHTS IN RESPONSE TO A DEEPENING
UPPER TROUGH ACROSS THE REGION. A FRONTAL BOUNDARY IS PROJECTED TO
SHIFT SOUTHWARD TOWARD AND POSSIBLY INTO THE LOCAL AREA BEFORE
STALLING. THE GFS AND ECMWF HAVE COME INTO BETTER AGREEMENT IN THIS
00Z CYCLE REGARDING THE SOUTHWARD PROGRESSION OF THIS BOUNDARY
MOVING INTO THE AREA BY THURSDAY DUE TO A SHORTWAVE WRAPPING AROUND
THE BASE OF THE UPPER TROUGH NORTH OF THE AREA AND SFC WAVE
DEVELOPING ALONG THE BOUNDARY OFF OF THE GA/SC COAST BY THURSDAY.
THIS SHOULD TRANSLATE TO A WET PATTERN FOR SOUTH FLORIDA WITH SW LOW-
LEVEL FLOW AHEAD OF THE BOUNDARY AND PLENTY OF DEEP LAYER MOISTURE.
THE HIGHEST RAINFALL PROBABILITIES ARE PROJECTED TO SET UP AND
FOCUSING ALONG THE EAST COAST AREAS EACH AFTERNOON GOING INTO THE
WEEKEND EACH DAY.
/85
AVIATION...
SHOWERS AND STORMS WERE ONGOING ACROSS THE ATLANTIC WATERS...AND
ISOLATED SHOWERS WERE MOVING BACK INTO THE EAST COAST NEAR KFLL.
SHOWERS MAY MOVE BACK INTO THE EAST COAST OVERNIGHT AND THEN TAPER
OFF IN THE MORNING. BRIEF MVFR/IFR CONDITIONS ARE POSSIBLE. GUIDANCE
IS INDICATING DRIER AIR MAY BEGIN MOVING INTO THE EASTERN PORTIONS
OF THE REGION IN THE AFTERNOON. SO REMOVED VCTS FOR THE EAST COAST
METRO AREAS FOR THE AFTERNOON HOURS. LIGHT WINDS EARLY THIS MORNING
WILL BECOME SOUTHEAST AROUND 10 KNOTS IN THE AFTERNOON...AND THEN
DIMINISH AGAIN IN THE EVENING. FOR KAPF...A WEAK GULF COAST SEA
BREEZE MAY DEVELOP IN THE AFTERNOON. THE BEST CHANCE OF STORMS NEAR
KAPF IS ALSO FORECAST TO BE IN THE AFTERNOON.
/84
MARINE...
AN UPPER LOW WILL KEEP THE RAIN CHANCES IN THE FORECAST ACROSS THE
MARINE AREAS THROUGH THE REMAINDER OF THE WEEKEND WITH LIGHT TO
MODERATE SOUTHEAST WINDS CONTINUING. WINDS AND SEAS WILL BE LOCALLY
HIGHER IN AND AROUND HEAVIER SHOWERS AND STORMS. HIGH PRESSURE WILL
BUILD BACK ACROSS THE REGION THROUGH THE FIRST HALF OF THE UPCOMING
WEEK WITH SOUTHEAST WINDS CONTINUING. A COLD FRONT WILL APPROACH
FROM THE NORTH AND MAY LEAD TO SOUTH AND SOUTHWEST WINDS BY THE END
OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 77 87 77 / 40 20 40 20
FORT LAUDERDALE 87 79 88 79 / 30 20 30 20
MIAMI 87 78 88 78 / 20 20 30 20
NAPLES 88 75 90 76 / 70 20 40 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...85/AG
LONG TERM....85/AG
AVIATION...21/KM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
708 AM EDT SUN SEP 14 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 457 AM EDT SUN SEP 14 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS SHORTWAVE/PV
ANOMALY UPSTREAM OVER NRN MN. PV ADVECTION AND 290-295K ISENTROPIC
ASCENT AHEAD OF THIS FEATURE HAS PRODUCED NARROW LINE OF SHRA FROM
WRN TIP OF LAKE SUPERIOR OVER THE MN ARROWHEAD EARLY THIS MORNING.
TODAY...MODEL CONSENSUS INDICATES SHORTWAVE WILL TRACK ACROSS NRN
LAKE SUPERIOR TODAY AND THEN EXIT NE OF THE LAKE LATE THIS
AFTERNOON. PV ADVECTION...ISENTROPIC ASCENT AND LOWERING
CONDENSATION PRES DEFICITS SUGGEST MUCH OF PCPN WITH THIS SYSTEM
WILL STAY ALONG AND NORTH OF PROJECTED VORT TRACK. WILL MAINTAIN
SLIGHT CHC TO LOW CHC POPS OVER MAINLY THE NRN TIER OF UPPER MI WITH
HIGHER CHC POPS OVER LAKE SUPERIOR TODAY ALONG/AHEAD OF COLD FRONTAL
PASSAGE. EXPECT HIGH TEMPS GENERALLY IN THE UPPER 50S TO LWR 60S.
TONIGHT...WITH SHORTWAVE AND ASSOC FORCING ALREADY NE OF LAKE
SUPERIOR...EXPECT SHRA OVER ERN COUNTIES TO DIMINISH QUICKLY THIS
EVENING ALONG FRONTAL BOUNDARY. WL MAINTAIN SLIGHT CHC POPS THIS
EVENING FOR ERN COUNTIES BUT OTHERWISE EXPECT DRYING/PARTIAL
CLEARING THIS EVENING FROM THE WEST BEHIND THE FRONT. EXPECT LOW
TEMPS TO RANGE IN THE UPPER 30S OVER MUCH OF THE WRN INTERIOR AND
THE TYPICAL COLD SPOTS OF THE ERN INTERIOR TO THE MID TO UPPER 40S
NEAR THE GREAT LAKES.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 401 AM EDT SUN SEP 14 2014
FOR MON...A SHORTWAVE LOOKS TO MOVE INTO THE UPPER TROUGH POSITIONED
OVER THE GREAT LAKES REGION...BUT THE SHORTWAVE WILL BE BEHIND A SFC
COLD FRONT THAT WILL MOVE THROUGH ABOUT 12 HOURS AHEAD ON SUN NIGHT.
GIVEN THAT THE BEST MOISTURE WILL BE ALONG AND AHEAD OF THE FRONT AS
A 1022MB SFC HIGH OVER THE PLAINS NOSES INTO THE REGION BEHIND THE
FRONT...WIDESPREAD PRECIP IS NOT EXPECTED ON MON. COULD SEE
SCATTERED SHOWERS AS THE SHORTWAVE PASSES OR RIGHT BEHIND THE
SHORTWAVE AS THE 850MB THERMAL TROUGH PASSES...WHICH MAY PROVIDE
SOME ADDITIONAL WEAK INSTABILITY. HIGH TEMPS WILL BE IN THE 50S.
THE UPPER TROUGH INTENSIFIES AND MOVES SLOWLY E THROUGH MID WEEK AS
THE UPPER RIDGE OVER THE WRN CONUS MOVES OVER THE ROCKIES. UPPER
LEVEL ENERGY TUE THROUGH THU WILL BE MAINLY N/NE OF THE CWA...BUT
SOME LOWER LEVEL FEATURES MAY LEAD TO SOME RAIN. MODELS GENERALLY
AGREE THAT A WEAK COLD FRONT WILL MOVE IN FROM THE N/NNE TUE NIGHT
AND THEN STALL OVER THE AREA WHILE DIMINISHING WED INTO THU. BEST
CHANCES FOR PRECIP DURING THIS TIME IS TUE NIGHT INTO WED SINCE A
SFC HIGH MOVES JUST N/NE OF THE CWA WED NIGHT INTO THU...RESULTING
IN A DRIER AIRMASS. ADDITIONALLY...THERE IS POTENTIAL FOR FRONT MON
NIGHT AND WED NIGHT.
THE PATTERN BECOMES MORE PROGRESSIVE FRI INTO SAT...WHICH MAY LEAD
TO A LOW PRESSURE SYSTEM OR JUST A TROUGH MOVING IN FROM THE W ON
SAT. THERE IS DISAGREEMENT BETWEEN MODELS FOR FRI AND SAT...WHICH IS
TO BE EXPECTED GIVEN THE MORE PROGRESSIVE/TRANSITIONAL FLOW. GENERAL
CONSENSUS DOES SHOW WAA FRI INTO EARLY SAT...BRINGING A WARMER
AIRMASS WITH 850MB TEMPS OF 13C-15C. PRECIP WILL BE POSSIBLE DURING
THIS TIME GIVEN THE WAA...POSSIBLE SHORTWAVE ENERGY HINTED AT BY
MODELS...AND THE ARRIVAL OF A SFC LOW OR TROUGH. DEPENDING ON AMOUNT
OF CLEARING...MAY SEE TEMPS TOP OUT IN THE 70S IN SPOTS BOTH
DAYS...BUT WILL LEAN MORE TOWARD COOLER CONSENSUS GUIDANCE GIVEN THE
CHANCES FOR PRECIP/CLOUD COVER...WHICH HAS HIGHS IN THE MID 60S TO
70.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 655 AM EDT SUN SEP 14 2014
UNDER RELATIVELY DRY LOW LEVELS...VFR CONDITIONS SHOULD PREVAIL THRU
THE FCST PERIOD AT KIWD/KCMX/KSAW. AN APPROACHING COLD FRONT SHOULD
BRING SCT -SHRA INTO NW UPPER MI BY AFTN. HAVE INCLUDED A VCSH
MENTION AT KCMX. SW WINDS GUSTING TO 20 KT WILL SHIFT W BEHIND THE
FRONT THIS AFTERNOON AND MAY GUST AS HIGH AS 25 KTS AT KCMX BEFORE
TAPERING OFF TOWARD EVENING. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 457 AM EDT SUN SEP 14 2014
A LOW PRES TROF OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY AS
S TO SW WINDS OF 10-20 KT SHIFT WEST ACROSS THE LAKE. THERE MAY BE
PERIODS OF SOMEWHAT HIGHER WINDS TO 25 KTS LATE MON NIGHT THRU EARLY
WED AHEAD OF AND BEHIND A COLD FRONT THAT WILL DROP S ACROSS LAKE
SUPERIOR TUE. LIGHTER WINDS WILL THEN BE THE RULE LATER WED THRU THU
HAS HIGH PRES MOVE SE ACROSS NRN ONTARIO TOWARD THE LOWER LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
653 AM CDT SUN SEP 14 2014
.UPDATE...
ISSUED AT 652 AM CDT SUN SEP 14 2014
DESPITE MID LEVEL CLOUDINESS IN AN AREA OF WEAK FRONTOGENESIS AND
DECENT ELEVATED INSTABILITY...ECHOES HAVE DECREASED ACROSS CHERRY
COUNTY THIS MORNING AND HAVE THEREFORE PULLED THEM FROM THE FCST.
OTHERWISE NO MAJOR CHANGES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CDT SUN SEP 14 2014
MAIN UPPER PV ANOMALY LOCATED ACROSS NRN ND WILL CONTINUE ITS QUICK
EWD PROGRESSION TO THE NRN GREAT LAKES REGION THROUGH THE DAY WHILE
ASSOCIATED FRONT LOSES SWD MOMENTUM AND IS PROGGED BY THE MODELS TO
STALL ACROSS NRN NEB. THIS IS IN LINE WITH CURRENT PRESSURE FIELDS
EARLY THIS MORNING AS BEST FALLS ARE OVER NRN MN AND WEAK RISES
BEHIND THE FRONT AS IT ENTERS THE NRN PORTION OF THE STATE. UNDULAR
BORE EVIDENT WITH THE FRONT CURRENTLY ON KLNX 88D INDICATING STABLE
LOW LEVELS...HOWEVER RAP ANALYSIS AND IR IMAGERY SUGGEST SMALL AREA
OF WEAK MID LEVEL FRONTOGENESIS INDICATIVE OF DEVELOPING WARM AIR
ADVECTION ACROSS NWRN FCST AREA CURRENTLY AND LIKELY TAPPING WEAK
INSTABILITY BASED ON CONVECTIVE NATURE TO CLOUDS...AND ECHOES
SHOWING UP ALOFT ON KLNX 88D. FOR THE REST OF THE AREA...VERY LITTLE
IN THE WAY OF CLOUDS ASSOCIATED WITH THE FRONT WHICH IS EVIDENCE OF
ITS KATABATIC NATURE WITH 0.5KM/1KM AND 700 MB VWP WINDS FROM AREA
RADARS AND RAP SHORT TERM FCST SOUNDINGS SHOWING NWRLY WINDS AHEAD
OF THE FRONT. HAVE INCLUDED SPRINKLES EARLY THIS MORNING BASED ON
RADAR TRENDS MENTIONED ABOVE.
AS UPPER PV ANOMALY AND ASSOCIATED UPPER LOW MOVES INTO NRN MN THIS
MORNING...MID AND UPPER FLOW BECOMES ZONAL ACROSS THE CENTRAL
ROCKIES AND HIGH PLAINS. IN RESPONSE...MID LEVEL WINDS BECOME SWRLY
WHICH WILL ADVECT THE EML EWD OVER THE EWD ADVANCING DRYLINE ACROSS
ERN CO...AS LOWER LEVEL WINDS BACK AND BECOME S/SERLY DURING THE
AFTERNOON. NAM PROGS SFC DEW POINTS INTO THE MID 50S ACROSS SWRN
NEB...HOWEVER THE AFOREMENTIONED EML DEVELOPS A SIGNIFICANT CAP EAST
OF THE DRYLINE IN SWRN NEB DURING THE AFTERNOON HOURS. SCT/BKN CLOUD
COVER IS EXPECTED EAST OF THE DRYLINE AS WELL WHICH WILL BE EVIDENCE
OF THE HIGHER LOW LEVEL THETA E AND HIGHER CAPE. HOWEVER...DESPITE
THE NEXT APPROACHING UPPER PV ANOMALY AND STALLED SFC BOUNDARY
ACROSS THE NRN PORTION OF THE STATE...AND THE PREVIOUSLY MENTION
HIGHER CAPE AND DECENT SHEAR...THE CAP IS EXPECTED TO BE TOO STRONG
TO ALLOW CONVECTIVE INITIATION DURING THE AFTERNOON IN WRN NEB.
HOWEVER...CONVECTION ALLOWING MODELS /CAMS/ ARE QUICKER TO DEVELOP
STORMS ACROSS NRN NEB INTO SERN SD BY EVENING WHICH WILL BE CLOSER
TO MAIN UPPER LEVEL SUPPORT AND SFC WARM FRONT SO PRECIP CHANCES
WILL BE RETAINED IN THE NERN PORTION OF THE FCST AREA...THOUGH MAY
BE PUSHED BACK IN TIME A LITTLE.
NEXT SIGNIFICANT UPPER PV ANOMALY AND ASSOCIATED UPPER LOW WILL MOVE
INTO THE NRN PLAINS THIS EVENING AND SUNDAY NIGHT. THIS WILL GIVE A
NUDGE TO THE STALLED SFC BOUNDARY AND WILL MOVE IT SWD
SOMEWHAT...BUT THE HIGH PLAINS NOCTURNAL LOW LEVEL JET WILL DEVELOP
AS DRIER AIR ACROSS THE HIGHER ELEVATIONS FURTHER WEST COOLS RAPIDLY
AFTER SUNSET...BUT ALSO PARTLY IN RESPONSE TO THE LOWERING HEIGHTS
ACROSS THE NRN PLAINS. THIS LIFT WILL BE ABLE TO TAP THE ELEVATED
INSTABILITY STILL RESIDING ACROSS SWRN NEBR TO DEVELOP THUNDERSTORMS
OVERNIGHT SUNDAY NIGHT AS THE FRONT SLOWLY CONTINUES TO SAG ACROSS
THE REMAINDER OF THE STATE. THOUGH THE NAM SUPPORTS PRECIP IN THE
SWRN PORTION OF THE STATE OVERNIGHT...CAMS FOCUS MOST OF THE PRECIP
ALONG THE COLD FRONT IN NRN NEB.
AS FOR TEMPERATURES...DESPITE DEVELOPING CLOUD COVER DURING THE
AFTERNOON IN THE SW...TEMPS WILL BE MUCH WARMER WITH INCREASING SRLY
WINDS BUT WILL BE SLIGHTLY COOLER ACROSS THE NORTH AS WINDS BECOME
ERLY NORTH OF THE WARM FRONT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 342 AM CDT SUN SEP 14 2014
QUASI-ZONAL UPPER TROPOSPHERIC FLOW TO PREVAIL BEHIND A PASSING
NORTHERN PLAINS WAVE EARLY IN THE EXTENDED...BUT WILL EVENTUALLY
GIVE WAY TO NORTHWESTERLY AS A WESTERN CONUS RIDGE BUILDS EAST. AS
A RESULT A GENERAL LACK OF OMEGA IS ANTICIPATED ATOP MUCH OF THE
FORECAST AREA THROUGH TUESDAY AFTERNOON...WITH THE MODELS
PROJECTING NO ATMOSPHERIC DISTURBANCES IMPACTING THE REGION.
TUESDAY EVENING INTO WEDNESDAY...THE OPERATIONAL MODELS /GFS
INITIALLY...THEN ECMWF WEDNESDAY MORNING/ GENERATES MEASURABLE QPF
ACROSS SOUTHEASTERN PORTIONS OF THE CWA...THE MODELS ARE KEYING ON
SUFFICIENT THERMAL ADVECTION/UPGLIDE IN THE 305-310K SFC FOR
PRECIPITATION PRODUCTION. DESPITE THIS...DECIDED TO LEAVE QPF OUT
OF THE FORECAST AS PROXIMITY AND BUFR SOUNDINGS SUGGEST A MOISTURE
CHALLENGED ATMOSPHERE ABOVE THE BOUNDARY LAYER WITH THE GFS
SHOWING SIGNIFICANT DRY MID LEVELS. WITH THIS IN MIND...FELT THAT
POPS WILL BE ISOLATED AT BEST IN COVERAGE WITH QPF AMOUNTS LIGHT.
IF SHOWERS/STORMS ARE TO GO...SOUTHEASTERN PORTIONS OF THE CWA
OVERNIGHT TUESDAY INTO EARLY WEDNESDAY WOULD BE THE MOST LIKELY OF
LOCATIONS. ADDITIONAL THERMAL ADVECTION INDUCED STORMS ARE SHOWN
WEDNESDAY NIGHT INTO THURSDAY...BUT MOSTLY REMOVED /SOUTH AND
EAST/ FROM OUR CWA. CR ALLBLEND PULLED ALL MENTION OF QPF OUT OF
OUR CWA DURING THIS TIME PERIOD...WHICH IS FINE FOR NOW. UPPER
PATTERN UNDERGOES A CHANGE LATE IN THE WEEK WITH THE APPROACH OF A
WESTERN CONUS TROUGH AND ATTENDANT COLD FRONT PASSAGE. THE
TROUGH/COLD FRONT WILL SUPPRESS THE RIDGE EAST OF THE FORECAST
AREA LATE WEEK AND PROVIDE FOR PRECIPITATION. THE GFS IN
COMPARISON TO THE EC REMAINS MUCH STRONGER WITH THIS LATE WEEK
TROUGH AND MORE FAVORABLE FOR WIDESPREAD SHOWERS/STORMS. THE CR
ALLBLEND PROCEDURE RAMPS UP POPS STARTING FRIDAY...WITH POPS
MAXIMIZED NEAR 40 PERCENT FOR SATURDAY AND INTO EARLY SUNDAY. TO
BE HONEST...REALLY NOT TOO KEEN ON 4 PERIODS OF QPF THAT IS
ASSOCIATED WITH THE PASSAGE OF THIS DISTURBANCE/FRONT...ESPECIALLY
IN A SOMEWHAT PROGRESSIVE PATTERN...BUT WILL LEAVE THE PROCEDURE
UNCHANGED DUE TO THE USUAL TIMING/STRENGTH DIFFERENCES SEEN THIS
FAR OUT.
DRIZZLE REPLACED THE SLIGHT CHANCE MENTION OF QPF FROM 12-15Z THIS
MONDAY AS PROXIMITY SOUNDINGS REVEAL DRYING ALOFT...BUT A SATURATED
BL WITH WEAK LIFT. THIS DRIZZLE SHOULD NOT LAST LONG AS PROXIMITY
SOUNDINGS REVEAL RAPID BL DRYING BEHIND THE FRONT. WILL ALSO NEED
TO MONITOR THE RETURN OF LOW LEVEL MOISTURE EARLY TUESDAY AS SURFACE
HIGH PRESSURE BUILDS EAST OF THE MISSOURI VALLEY. NAM12 0.5AGL RH
WOULD INDICATE A SIGHT POTENTIAL OF FOG ACROSS SOUTHWEST
NEBRASKA...BUT CONFIDENCE WAS NOT SUFFICIENT TO INCLUDE THE MENTION
WITH THIS FORECAST.
RETURN SOUTHERLY FLOW AND RESULTANT THERMAL ADVECTION WILL PROMOTE A
WARMING TREND MONDAY THROUGH MID-LATE WEEK...WIDESPREAD HIGHS IN THE
80S BY THURSDAY ARE ANTICIPATED. WARMEST READINGS WILL BE ACROSS
OUR WEST EACH DAY WITH A GREATER INFLUENCE FROM THE UPPER TROPOSPHERIC
RIDGE. OVERNIGHT LOWS WILL BENEFIT AS WELL...RISING FROM THE 40S
MONDAY MORNING...TO POSSIBLY THE 50S TO 60S BY WEEKS END.
TEMPERATURES COOL LATE WEEK BEHIND THE FRONT...BUT AT THAT...NOT
ANTICIPATING WHAT WE SAW A FEW DAYS AGO...NO FROST OR FREEZE
ISSUES ARE EXPECTED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 652 AM CDT SUN SEP 14 2014
AVIATION FCST DIFFICULTY LIES WITH EXTENT OF TSRA THIS
EVE/TONIGHT ALONG COLD FRONT. HAVE LEFT IT OUT OF KVTN DUE TO
UNCERTAIN EXTENT OF DEVELOPMENT ACROSS NC NEB...THOUGH SHORT RANGE
MODELS INDICATING THERE SHOULD BE GOOD COVERAGE BUT POSSIBLY
FURTHER EAST. FOR KVTN HOWEVER WILL BE THE POTENTIAL FOR MVFR
CONDITIONS LATER TONIGHT. FURTHER S NEAR KLBF BELIEVE LLJ SHOULD
CONTRIBUTE TO DEVELOPMENT THERE AND HAVE THEREFORE LEFT A PROB30
GROUP IN. OTHERWISE VFR FOR THE MOST PATRT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JWS
SHORT TERM...JWS
LONG TERM...JACOBS
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
653 PM EDT SUN SEP 14 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 401 PM EDT SUN SEP 14 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM CENTRAL CANADA INTO THE NRN CONUS. A SHORTWAVE TROUGH WAS
MOVING THROUGH NRN ONTARIO JUST N OF LAKE SUPERIOR WHILE THE MOST
PROMINENT UPSTREAM SHRTWV WAS DIVING INTO ERN MONTANA. AT THE
SFC...LOW PRES NEAR CYQT HAD DRAGGED A COLD FRONT THROUGH WRN UPPER
MI. THE SHRTWV TAIL AHEAD OF THE COLD FRONT WITH MODERATE 700-300
QVECTOR CONV WAS ENOUGH TO SUPPORT SCT LIGHT SHOWERS OR SPRINKLES
FROM ERN LAKE SUPERIOR INTO CNTRL UPPER MI. RELATIVELY DRY LOW LEVEL
AND THE QUICK MOVEMENT OF THE SHOWERS HAS LIMITED POTENTIAL FOR MORE
THAN TRACE PCPN AMOUNTS. OTHERWISE...PARTIAL CLEARING WAS MOVING
INTO W UPPER MI WITH A PROMINENT CU FIELD IN THE SEASONABLY COOL
AIRMASS WHERE 850 MB TEMPS WERE NEAR 4C.
TONIGHT...AS THE SHRTWV TROUGH EXITS TO THE EAST...EXPECT THE
REMAINING SHOWERS OVER THE ERN CWA TO DIMINISH THROUGH THE LATE
AFTERNOON AND EARLY EVENING. PARTLY CLOUDY SKIES AND DIMINISHING
WINDS WILL RESULT IN FAVORABLE RADIATIONAL COOLING CONDITIONS LATE
THIS EVENING. HOWEVER...THERE IS UNCERTAINTY ON HOW MUCH CLOUD COVER
WILL HOLD TOGETHER OVERNIGHT AS ADDITIONAL MOISTURE WILL SLIDE IN
WITH 850 MB TEMPS DROPPING TO NEAR 1C. EXPECT MIN READINGS TO DROP
INTO THE UPPER 30S AND LOWER 40S INLAND.
MONDAY...MODELS WERE IN GOOD AGREEMENT THAT THE STRONGEST QVECTOR
CONV AND PCPN ASSOCIATED WITH THE MONTANA SHRTWV WILL REMAIN SOUTH
OF UPPER MI. HOWEVER...THERE MAY BE ENOUGH LOW LEVEL MOISTURE
COMBINED WITH 850 MB TEMPS NEAR 1C TO SUPPORT SOME SHALLOW
CONVECTION WITH SCATTERED LIGHT SHOWERS OR SPRINKLES AS DAYTIME
HEATING INCREASES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 350 PM EDT SUN SEP 14 2014
MODEL AGREEMENT IS GOOD IN THE EVOLUTION OF OVERALL LARGE SCALE
PATTERN INTO NEXT WEEKEND. TROUGHS CENTERED OVER ALASKA AND NUNAVUT
IN NORTHERN CANADA ARE EXPECTED TO DEAMPLIFY WITH FLOW ALOFT OVER
THE NORTHERN CONUS BECOMING MORE ZONAL THROUGH THE PERIOD. UNTIL
MIDWEEK THE TROUGH OVER THE GREAT LAKES AND ACROSS EASTERN CANADA
WILL KEEP GETTING REINORCED AS UPPER JET ENERGY DIGGING SSE OVER
WESTERN CANADA SLIDES INTO BASE OF TROUGH. STRONGER SHORTWAVE
WITHIN THE TROUGH CROSSES NORTHERN ONTARIO MONDAY NIGHT AND MOVES
INTO QUEBEC ON TUESDAY. COLD FRONT TIED TO THAT WAVE ALONG WITH
ANOTHER SHEARED OUT SHORTWAVE AND RIBBON OF HIGHER H85-H7 RH MAY
RESULT IN LGT RAIN OR SHOWERS TURSDAY NIGHT INTO WEDNESDAY AND
POSSIBLY EVEN INTO WEDNESDAY NIGHT IF THE ECMWF AND GEM-NH ARE ON
THE RIGHT TRACK. MAIN IMPACT WILL BE A NOTICABLE COOLER DAY ON
WEDNESDAY COMPARED TO TUESDAY WHERE TEMPS WILL ACTUALLY BE AROUND OR
EVEN SLIGHTLY ABOVE NORMAL /NORMAL HIGHS AVERAGE THE MID 60S FOR
MID SEPT/.
SFC HIGH PRESSURE BUILDS ACROSS WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT IN CONFLUENT FLOW IN UPPER LEVELS BTWN RIDGING EXPANDING OVER
THE WESTERN CONUS AND DEPARTING TROUGH OVER EASTERN CANADA. MAINLY
DRY WEATHER ALONG WITH PARTLY CLOUDY OR MOSTLY CLEAR SKIES SHOULD
RESULT. STILL COULD BE CHILLY OVER THE INLAND AREAS ON WEDNESDAY
NIGHT WITH FROST. HOWEVER...BASED ON THAT SIGNAL OF MID-LEVEL
MOISTURE RIBBON FM ECMWF/GEM-NH...LOWEST TEMPS AND GREATEST RISK OF
FROST MIGHT END UP OVER THE INTERIOR EAST CWA.
BY LATE THIS WEEK...RIDGING OVER THE WESTERN CONUS IS REPLACED BY
TROUGHING AS SHORTWAVE AND UPPER JET STREAKS CURRENTLY OVER PACIFIC
WELL OFFSHORE OF WESTERN CONUS COAST SLIDES ACROSS THE NORTHERN AND
CENTRAL PLAINS WITH A SFC TROUGH ALSO PUSHING WEST TO EAST. MAIN
QUESTION IS HOW QUICKLY THIS OCCURS. NO REAL TREND IN THE MODEL
GUIDANCE...AS THE ECMWF AND GFS HAVE JUMPED AROUND IN HOW QUICKLY TO
BRING THE TROUGH AND INITIAL SURGE OF H85 THETA-E ADVECTION ACROSS
THE NORTHERN PLAINS AND DOWNSTREAM INTO THE UPPER GREAT LAKES. ONCE
THE FRONT...AND MORE SO THE THETA-E ADVECTION AHEAD OF THE FRONT...
ARRIVES COULD BE MULTIPLE ROUNDS OF SHRA/TSRA LATER FRIDAY THROUGH
SATURDAY WITH MAINLY JUST SHRA ON SUNDAY. HEAVY RAINS POSSIBLE SINCE
THE SFC FRONT WOULD BE PARALLEL TO THE UPPER LEVEL FLOW AND PWATS
ARE FORECAST 200-250 PCT OF NORMAL. AT FIRST GLANCE AND IT IS JUST
THAT...LOOKS LIKE ONLY A SMALLER RISK OF SEVERE WX AS INITIAL
ELEVATED INSTABILITY...MAYBE UP TO 500 J/KG...ON FRIDAY/FRIDAY NIGHT
DOES NOT LINK UP WITH MUCH EFFECTIVE SHEAR. THEN AS PRIMARY FRONT
COMES THROUGH EITHER SATURDAY AS IT LOOKS NOW...APPEARS BETTER
MLCAPE REMAINS SOUTH OF THE AREA CLOSER TO AREA OF 65F SFC DWPNTS.
ALL THAT SAID...GIVEN THE STRONG WINDS ALOFT THAT WILL BE
PRESENT...IF INSTABILITY ENDS UP GREATER THAN FORECAST...WOULD BE AT
LEAST SOME RISK OF STRONGER STORMS FRIDAY THROUGH SUNDAY. MAX TEMPS
BOTH FRI AND SAT MAY TRY TO REACH 70 DEGREES IF THERE IS ENOUGH
BREAKS IN THE CLOUD COVER AS H85 TEMPS ARE WELL ABOVE +12C. A BIT
LOWER TEMPS NEXT SUNDAY...THOUGH COOLDOWN WILL NOT BE AS MUCH AS
THAT EXPECTED ON WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 652 PM EDT SUN SEP 14 2014
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THROUGH THE FCST
PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 350 PM EDT SUN SEP 14 2014
SW WINDS GUST TO 25 KTS THROUGH EARLY THIS EVENING...THEN WEST
WINDS DIMINISH TO LESS THAN 20 KTS LATER TONIGHT INTO MONDAY. WEST
WINDS MAY INCREASE TO 25 KTS MONDAY NIGHT INTO TUESDAY AHEAD OF A
COLD FRONT. WINDS THEN SHIFT TO NORTHEAST UP TO 25 KTS IN WAKE OF
THE COLD FRONT TUESDAY NIGHT. WINDS DIMINISH TO LESS THAN 20 KTS
LATER WED INTO THU AS HIGH PRESSURE RIDGE CROSSES REGION. NEXT
CHANCE OF STRONG WINDS ARRIVES FRIDAY WITH SOUTH WINDS INCREASING
TO 20 TO 30 KTS AHEAD OF DEVELOPING LOW PRESSURE SYSTEM IN THE
PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...07
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
402 PM EDT SUN SEP 14 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 401 PM EDT SUN SEP 14 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM CENTRAL CANADA INTO THE NRN CONUS. A SHORTWAVE TROUGH WAS
MOVING THROUGH NRN ONTARIO JUST N OF LAKE SUPERIOR WHILE THE MOST
PROMINENT UPSTREAM SHRTWV WAS DIVING INTO ERN MONTANA. AT THE
SFC...LOW PRES NEAR CYQT HAD DRAGGED A COLD FRONT THROUGH WRN UPPER
MI. THE SHRTWV TAIL AHEAD OF THE COLD FRONT WITH MODERATE 700-300
QVECTOR CONV WAS ENOUGH TO SUPPORT SCT LIGHT SHOWERS OR SPRINKLES
FROM ERN LAKE SUPERIOR INTO CNTRL UPPER MI. RELATIVELY DRY LOW LEVEL
AND THE QUICK MOVEMENT OF THE SHOWERS HAS LIMITED POTENTIAL FOR MORE
THAN TRACE PCPN AMOUNTS. OTHERWISE...PARTIAL CLEARING WAS MOVING
INTO W UPPER MI WITH A PROMINENT CU FIELD IN THE SEASONABLY COOL
AIRMASS WHERE 850 MB TEMPS WERE NEAR 4C.
TONIGHT...AS THE SHRTWV TROUGH EXITS TO THE EAST...EXPECT THE
REMAINING SHOWERS OVER THE ERN CWA TO DIMINISH THROUGH THE LATE
AFTERNOON AND EARLY EVENING. PARTLY CLOUDY SKIES AND DIMINISHING
WINDS WILL RESULT IN FAVORABLE RADIATIONAL COOLING CONDITIONS LATE
THIS EVENING. HOWEVER...THERE IS UNCERTAINTY ON HOW MUCH CLOUD COVER
WILL HOLD TOGETHER OVERNIGHT AS ADDITIONAL MOISTURE WILL SLIDE IN
WITH 850 MB TEMPS DROPPING TO NEAR 1C. EXPECT MIN READINGS TO DROP
INTO THE UPPER 30S AND LOWER 40S INLAND.
MONDAY...MODELS WERE IN GOOD AGREEMENT THAT THE STRONGEST QVECTOR
CONV AND PCPN ASSOCIATED WITH THE MONTANA SHRTWV WILL REMAIN SOUTH
OF UPPER MI. HOWEVER...THERE MAY BE ENOUGH LOW LEVEL MOISTURE
COMBINED WITH 850 MB TEMPS NEAR 1C TO SUPPORT SOME SHALLOW
CONVECTION WITH SCATTERED LIGHT SHOWERS OR SPRINKLES AS DAYTIME
HEATING INCREASES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 350 PM EDT SUN SEP 14 2014
MODEL AGREEMENT IS GOOD IN THE EVOLUTION OF OVERALL LARGE SCALE
PATTERN INTO NEXT WEEKEND. TROUGHS CENTERED OVER ALASKA AND NUNAVUT
IN NORTHERN CANADA ARE EXPECTED TO DEAMPLIFY WITH FLOW ALOFT OVER
THE NORTHERN CONUS BECOMING MORE ZONAL THROUGH THE PERIOD. UNTIL
MIDWEEK THE TROUGH OVER THE GREAT LAKES AND ACROSS EASTERN CANADA
WILL KEEP GETTING REINORCED AS UPPER JET ENERGY DIGGING SSE OVER
WESTERN CANADA SLIDES INTO BASE OF TROUGH. STRONGER SHORTWAVE
WITHIN THE TROUGH CROSSES NORTHERN ONTARIO MONDAY NIGHT AND MOVES
INTO QUEBEC ON TUESDAY. COLD FRONT TIED TO THAT WAVE ALONG WITH
ANOTHER SHEARED OUT SHORTWAVE AND RIBBON OF HIGHER H85-H7 RH MAY
RESULT IN LGT RAIN OR SHOWERS TURSDAY NIGHT INTO WEDNESDAY AND
POSSIBLY EVEN INTO WEDNESDAY NIGHT IF THE ECMWF AND GEM-NH ARE ON
THE RIGHT TRACK. MAIN IMPACT WILL BE A NOTICABLE COOLER DAY ON
WEDNESDAY COMPARED TO TUESDAY WHERE TEMPS WILL ACTUALLY BE AROUND OR
EVEN SLIGHTLY ABOVE NORMAL /NORMAL HIGHS AVERAGE THE MID 60S FOR
MID SEPT/.
SFC HIGH PRESSURE BUILDS ACROSS WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT IN CONFLUENT FLOW IN UPPER LEVELS BTWN RIDGING EXPANDING OVER
THE WESTERN CONUS AND DEPARTING TROUGH OVER EASTERN CANADA. MAINLY
DRY WEATHER ALONG WITH PARTLY CLOUDY OR MOSTLY CLEAR SKIES SHOULD
RESULT. STILL COULD BE CHILLY OVER THE INLAND AREAS ON WEDNESDAY
NIGHT WITH FROST. HOWEVER...BASED ON THAT SIGNAL OF MID-LEVEL
MOISTURE RIBBON FM ECMWF/GEM-NH...LOWEST TEMPS AND GREATEST RISK OF
FROST MIGHT END UP OVER THE INTERIOR EAST CWA.
BY LATE THIS WEEK...RIDGING OVER THE WESTERN CONUS IS REPLACED BY
TROUGHING AS SHORTWAVE AND UPPER JET STREAKS CURRENTLY OVER PACIFIC
WELL OFFSHORE OF WESTERN CONUS COAST SLIDES ACROSS THE NORTHERN AND
CENTRAL PLAINS WITH A SFC TROUGH ALSO PUSHING WEST TO EAST. MAIN
QUESTION IS HOW QUICKLY THIS OCCURS. NO REAL TREND IN THE MODEL
GUIDANCE...AS THE ECMWF AND GFS HAVE JUMPED AROUND IN HOW QUICKLY TO
BRING THE TROUGH AND INITIAL SURGE OF H85 THETA-E ADVECTION ACROSS
THE NORTHERN PLAINS AND DOWNSTREAM INTO THE UPPER GREAT LAKES. ONCE
THE FRONT...AND MORE SO THE THETA-E ADVECTION AHEAD OF THE FRONT...
ARRIVES COULD BE MULTIPLE ROUNDS OF SHRA/TSRA LATER FRIDAY THROUGH
SATURDAY WITH MAINLY JUST SHRA ON SUNDAY. HEAVY RAINS POSSIBLE SINCE
THE SFC FRONT WOULD BE PARALLEL TO THE UPPER LEVEL FLOW AND PWATS
ARE FORECAST 200-250 PCT OF NORMAL. AT FIRST GLANCE AND IT IS JUST
THAT...LOOKS LIKE ONLY A SMALLER RISK OF SEVERE WX AS INITIAL
ELEVATED INSTABILITY...MAYBE UP TO 500 J/KG...ON FRIDAY/FRIDAY NIGHT
DOES NOT LINK UP WITH MUCH EFFECTIVE SHEAR. THEN AS PRIMARY FRONT
COMES THROUGH EITHER SATURDAY AS IT LOOKS NOW...APPEARS BETTER
MLCAPE REMAINS SOUTH OF THE AREA CLOSER TO AREA OF 65F SFC DWPNTS.
ALL THAT SAID...GIVEN THE STRONG WINDS ALOFT THAT WILL BE
PRESENT...IF INSTABILITY ENDS UP GREATER THAN FORECAST...WOULD BE AT
LEAST SOME RISK OF STRONGER STORMS FRIDAY THROUGH SUNDAY. MAX TEMPS
BOTH FRI AND SAT MAY TRY TO REACH 70 DEGREES IF THERE IS ENOUGH
BREAKS IN THE CLOUD COVER AS H85 TEMPS ARE WELL ABOVE +12C. A BIT
LOWER TEMPS NEXT SUNDAY...THOUGH COOLDOWN WILL NOT BE AS MUCH AS
THAT EXPECTED ON WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 132 PM EDT SUN SEP 14 2014
EXCEPT FOR SOME MVFR CIGS AT CMX EARLY THIS AFTERNOON...UNDER
RELATIVELY DRY LOW LEVELS...MAINLY VFR CONDITIONS WILL PREVAIL AT
THE TAF SITES THROUGH THE FCST PERIOD. ROACHING COLD FRONT WILL
BRING SCT -SHRA OR SPRINKLES AT SAW EARLY THIS AFTERNOON WHERE VCSH
WAS MENTIONED. SW WINDS GUSTING TO 20 KT WILL SHIFT W BEHIND THE
FRONT THIS AFTERNOON AND MAY GUST AS HIGH AS 25 KTS AT KCMX BEFORE
TAPERING OFF TOWARD EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 350 PM EDT SUN SEP 14 2014
SW WINDS GUST TO 25 KTS THROUGH EARLY THIS EVENING...THEN WEST
WINDS DIMINISH TO LESS THAN 20 KTS LATER TONIGHT INTO MONDAY. WEST
WINDS MAY INCREASE TO 25 KTS MONDAY NIGHT INTO TUESDAY AHEAD OF A
COLD FRONT. WINDS THEN SHIFT TO NORTHEAST UP TO 25 KTS IN WAKE OF
THE COLD FRONT TUESDAY NIGHT. WINDS DIMINISH TO LESS THAN 20 KTS
LATER WED INTO THU AS HIGH PRESSURE RIDGE CROSSES REGION. NEXT
CHANCE OF STRONG WINDS ARRIVES FRIDAY WITH SOUTH WINDS INCREASING
TO 20 TO 30 KTS AHEAD OF DEVELOPING LOW PRESSURE SYSTEM IN THE
PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
351 PM EDT SUN SEP 14 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 457 AM EDT SUN SEP 14 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS SHORTWAVE/PV
ANOMALY UPSTREAM OVER NRN MN. PV ADVECTION AND 290-295K ISENTROPIC
ASCENT AHEAD OF THIS FEATURE HAS PRODUCED NARROW LINE OF SHRA FROM
WRN TIP OF LAKE SUPERIOR OVER THE MN ARROWHEAD EARLY THIS MORNING.
TODAY...MODEL CONSENSUS INDICATES SHORTWAVE WILL TRACK ACROSS NRN
LAKE SUPERIOR TODAY AND THEN EXIT NE OF THE LAKE LATE THIS
AFTERNOON. PV ADVECTION...ISENTROPIC ASCENT AND LOWERING
CONDENSATION PRES DEFICITS SUGGEST MUCH OF PCPN WITH THIS SYSTEM
WILL STAY ALONG AND NORTH OF PROJECTED VORT TRACK. WILL MAINTAIN
SLIGHT CHC TO LOW CHC POPS OVER MAINLY THE NRN TIER OF UPPER MI WITH
HIGHER CHC POPS OVER LAKE SUPERIOR TODAY ALONG/AHEAD OF COLD FRONTAL
PASSAGE. EXPECT HIGH TEMPS GENERALLY IN THE UPPER 50S TO LWR 60S.
TONIGHT...WITH SHORTWAVE AND ASSOC FORCING ALREADY NE OF LAKE
SUPERIOR...EXPECT SHRA OVER ERN COUNTIES TO DIMINISH QUICKLY THIS
EVENING ALONG FRONTAL BOUNDARY. WL MAINTAIN SLIGHT CHC POPS THIS
EVENING FOR ERN COUNTIES BUT OTHERWISE EXPECT DRYING/PARTIAL
CLEARING THIS EVENING FROM THE WEST BEHIND THE FRONT. EXPECT LOW
TEMPS TO RANGE IN THE UPPER 30S OVER MUCH OF THE WRN INTERIOR AND
THE TYPICAL COLD SPOTS OF THE ERN INTERIOR TO THE MID TO UPPER 40S
NEAR THE GREAT LAKES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 350 PM EDT SUN SEP 14 2014
MODEL AGREEMENT IS GOOD IN THE EVOLUTION OF OVERALL LARGE SCALE
PATTERN INTO NEXT WEEKEND. TROUGHS CENTERED OVER ALASKA AND NUNAVUT
IN NORTHERN CANADA ARE EXPECTED TO DEAMPLIFY WITH FLOW ALOFT OVER
THE NORTHERN CONUS BECOMING MORE ZONAL THROUGH THE PERIOD. UNTIL
MIDWEEK THE TROUGH OVER THE GREAT LAKES AND ACROSS EASTERN CANADA
WILL KEEP GETTING REINORCED AS UPPER JET ENERGY DIGGING SSE OVER
WESTERN CANADA SLIDES INTO BASE OF TROUGH. STRONGER SHORTWAVE
WITHIN THE TROUGH CROSSES NORTHERN ONTARIO MONDAY NIGHT AND MOVES
INTO QUEBEC ON TUESDAY. COLD FRONT TIED TO THAT WAVE ALONG WITH
ANOTHER SHEARED OUT SHORTWAVE AND RIBBON OF HIGHER H85-H7 RH MAY
RESULT IN LGT RAIN OR SHOWERS TURSDAY NIGHT INTO WEDNESDAY AND
POSSIBLY EVEN INTO WEDNESDAY NIGHT IF THE ECMWF AND GEM-NH ARE ON
THE RIGHT TRACK. MAIN IMPACT WILL BE A NOTICABLE COOLER DAY ON
WEDNESDAY COMPARED TO TUESDAY WHERE TEMPS WILL ACTUALLY BE AROUND OR
EVEN SLIGHTLY ABOVE NORMAL /NORMAL HIGHS AVERAGE THE MID 60S FOR
MID SEPT/.
SFC HIGH PRESSURE BUILDS ACROSS WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT IN CONFLUENT FLOW IN UPPER LEVELS BTWN RIDGING EXPANDING OVER
THE WESTERN CONUS AND DEPARTING TROUGH OVER EASTERN CANADA. MAINLY
DRY WEATHER ALONG WITH PARTLY CLOUDY OR MOSTLY CLEAR SKIES SHOULD
RESULT. STILL COULD BE CHILLY OVER THE INLAND AREAS ON WEDNESDAY
NIGHT WITH FROST. HOWEVER...BASED ON THAT SIGNAL OF MID-LEVEL
MOISTURE RIBBON FM ECMWF/GEM-NH...LOWEST TEMPS AND GREATEST RISK OF
FROST MIGHT END UP OVER THE INTERIOR EAST CWA.
BY LATE THIS WEEK...RIDGING OVER THE WESTERN CONUS IS REPLACED BY
TROUGHING AS SHORTWAVE AND UPPER JET STREAKS CURRENTLY OVER PACIFIC
WELL OFFSHORE OF WESTERN CONUS COAST SLIDES ACROSS THE NORTHERN AND
CENTRAL PLAINS WITH A SFC TROUGH ALSO PUSHING WEST TO EAST. MAIN
QUESTION IS HOW QUICKLY THIS OCCURS. NO REAL TREND IN THE MODEL
GUIDANCE...AS THE ECMWF AND GFS HAVE JUMPED AROUND IN HOW QUICKLY TO
BRING THE TROUGH AND INITIAL SURGE OF H85 THETA-E ADVECTION ACROSS
THE NORTHERN PLAINS AND DOWNSTREAM INTO THE UPPER GREAT LAKES. ONCE
THE FRONT...AND MORE SO THE THETA-E ADVECTION AHEAD OF THE FRONT...
ARRIVES COULD BE MULTIPLE ROUNDS OF SHRA/TSRA LATER FRIDAY THROUGH
SATURDAY WITH MAINLY JUST SHRA ON SUNDAY. HEAVY RAINS POSSIBLE SINCE
THE SFC FRONT WOULD BE PARALLEL TO THE UPPER LEVEL FLOW AND PWATS
ARE FORECAST 200-250 PCT OF NORMAL. AT FIRST GLANCE AND IT IS JUST
THAT...LOOKS LIKE ONLY A SMALLER RISK OF SEVERE WX AS INITIAL
ELEVATED INSTABILITY...MAYBE UP TO 500 J/KG...ON FRIDAY/FRIDAY NIGHT
DOES NOT LINK UP WITH MUCH EFFECTIVE SHEAR. THEN AS PRIMARY FRONT
COMES THROUGH EITHER SATURDAY AS IT LOOKS NOW...APPEARS BETTER
MLCAPE REMAINS SOUTH OF THE AREA CLOSER TO AREA OF 65F SFC DWPNTS.
ALL THAT SAID...GIVEN THE STRONG WINDS ALOFT THAT WILL BE
PRESENT...IF INSTABILITY ENDS UP GREATER THAN FORECAST...WOULD BE AT
LEAST SOME RISK OF STRONGER STORMS FRIDAY THROUGH SUNDAY. MAX TEMPS
BOTH FRI AND SAT MAY TRY TO REACH 70 DEGREES IF THERE IS ENOUGH
BREAKS IN THE CLOUD COVER AS H85 TEMPS ARE WELL ABOVE +12C. A BIT
LOWER TEMPS NEXT SUNDAY...THOUGH COOLDOWN WILL NOT BE AS MUCH AS
THAT EXPECTED ON WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 132 PM EDT SUN SEP 14 2014
EXCEPT FOR SOME MVFR CIGS AT CMX EARLY THIS AFTERNOON...UNDER
RELATIVELY DRY LOW LEVELS...MAINLY VFR CONDITIONS WILL PREVAIL AT
THE TAF SITES THROUGH THE FCST PERIOD. ROACHING COLD FRONT WILL
BRING SCT -SHRA OR SPRINKLES AT SAW EARLY THIS AFTERNOON WHERE VCSH
WAS MENTIONED. SW WINDS GUSTING TO 20 KT WILL SHIFT W BEHIND THE
FRONT THIS AFTERNOON AND MAY GUST AS HIGH AS 25 KTS AT KCMX BEFORE
TAPERING OFF TOWARD EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 350 PM EDT SUN SEP 14 2014
SW WINDS GUST TO 25 KTS THROUGH EARLY THIS EVENING...THEN WEST
WINDS DIMINISH TO LESS THAN 20 KTS LATER TONIGHT INTO MONDAY. WEST
WINDS MAY INCREASE TO 25 KTS MONDAY NIGHT INTO TUESDAY AHEAD OF A
COLD FRONT. WINDS THEN SHIFT TO NORTHEAST UP TO 25 KTS IN WAKE OF
THE COLD FRONT TUESDAY NIGHT. WINDS DIMINISH TO LESS THAN 20 KTS
LATER WED INTO THU AS HIGH PRESSURE RIDGE CROSSES REGION. NEXT
CHANCE OF STRONG WINDS ARRIVES FRIDAY WITH SOUTH WINDS INCREASING
TO 20 TO 30 KTS AHEAD OF DEVELOPING LOW PRESSURE SYSTEM IN THE
PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
139 PM EDT SUN SEP 14 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 457 AM EDT SUN SEP 14 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS SHORTWAVE/PV
ANOMALY UPSTREAM OVER NRN MN. PV ADVECTION AND 290-295K ISENTROPIC
ASCENT AHEAD OF THIS FEATURE HAS PRODUCED NARROW LINE OF SHRA FROM
WRN TIP OF LAKE SUPERIOR OVER THE MN ARROWHEAD EARLY THIS MORNING.
TODAY...MODEL CONSENSUS INDICATES SHORTWAVE WILL TRACK ACROSS NRN
LAKE SUPERIOR TODAY AND THEN EXIT NE OF THE LAKE LATE THIS
AFTERNOON. PV ADVECTION...ISENTROPIC ASCENT AND LOWERING
CONDENSATION PRES DEFICITS SUGGEST MUCH OF PCPN WITH THIS SYSTEM
WILL STAY ALONG AND NORTH OF PROJECTED VORT TRACK. WILL MAINTAIN
SLIGHT CHC TO LOW CHC POPS OVER MAINLY THE NRN TIER OF UPPER MI WITH
HIGHER CHC POPS OVER LAKE SUPERIOR TODAY ALONG/AHEAD OF COLD FRONTAL
PASSAGE. EXPECT HIGH TEMPS GENERALLY IN THE UPPER 50S TO LWR 60S.
TONIGHT...WITH SHORTWAVE AND ASSOC FORCING ALREADY NE OF LAKE
SUPERIOR...EXPECT SHRA OVER ERN COUNTIES TO DIMINISH QUICKLY THIS
EVENING ALONG FRONTAL BOUNDARY. WL MAINTAIN SLIGHT CHC POPS THIS
EVENING FOR ERN COUNTIES BUT OTHERWISE EXPECT DRYING/PARTIAL
CLEARING THIS EVENING FROM THE WEST BEHIND THE FRONT. EXPECT LOW
TEMPS TO RANGE IN THE UPPER 30S OVER MUCH OF THE WRN INTERIOR AND
THE TYPICAL COLD SPOTS OF THE ERN INTERIOR TO THE MID TO UPPER 40S
NEAR THE GREAT LAKES.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 401 AM EDT SUN SEP 14 2014
FOR MON...A SHORTWAVE LOOKS TO MOVE INTO THE UPPER TROUGH POSITIONED
OVER THE GREAT LAKES REGION...BUT THE SHORTWAVE WILL BE BEHIND A SFC
COLD FRONT THAT WILL MOVE THROUGH ABOUT 12 HOURS AHEAD ON SUN NIGHT.
GIVEN THAT THE BEST MOISTURE WILL BE ALONG AND AHEAD OF THE FRONT AS
A 1022MB SFC HIGH OVER THE PLAINS NOSES INTO THE REGION BEHIND THE
FRONT...WIDESPREAD PRECIP IS NOT EXPECTED ON MON. COULD SEE
SCATTERED SHOWERS AS THE SHORTWAVE PASSES OR RIGHT BEHIND THE
SHORTWAVE AS THE 850MB THERMAL TROUGH PASSES...WHICH MAY PROVIDE
SOME ADDITIONAL WEAK INSTABILITY. HIGH TEMPS WILL BE IN THE 50S.
THE UPPER TROUGH INTENSIFIES AND MOVES SLOWLY E THROUGH MID WEEK AS
THE UPPER RIDGE OVER THE WRN CONUS MOVES OVER THE ROCKIES. UPPER
LEVEL ENERGY TUE THROUGH THU WILL BE MAINLY N/NE OF THE CWA...BUT
SOME LOWER LEVEL FEATURES MAY LEAD TO SOME RAIN. MODELS GENERALLY
AGREE THAT A WEAK COLD FRONT WILL MOVE IN FROM THE N/NNE TUE NIGHT
AND THEN STALL OVER THE AREA WHILE DIMINISHING WED INTO THU. BEST
CHANCES FOR PRECIP DURING THIS TIME IS TUE NIGHT INTO WED SINCE A
SFC HIGH MOVES JUST N/NE OF THE CWA WED NIGHT INTO THU...RESULTING
IN A DRIER AIRMASS. ADDITIONALLY...THERE IS POTENTIAL FOR FRONT MON
NIGHT AND WED NIGHT.
THE PATTERN BECOMES MORE PROGRESSIVE FRI INTO SAT...WHICH MAY LEAD
TO A LOW PRESSURE SYSTEM OR JUST A TROUGH MOVING IN FROM THE W ON
SAT. THERE IS DISAGREEMENT BETWEEN MODELS FOR FRI AND SAT...WHICH IS
TO BE EXPECTED GIVEN THE MORE PROGRESSIVE/TRANSITIONAL FLOW. GENERAL
CONSENSUS DOES SHOW WAA FRI INTO EARLY SAT...BRINGING A WARMER
AIRMASS WITH 850MB TEMPS OF 13C-15C. PRECIP WILL BE POSSIBLE DURING
THIS TIME GIVEN THE WAA...POSSIBLE SHORTWAVE ENERGY HINTED AT BY
MODELS...AND THE ARRIVAL OF A SFC LOW OR TROUGH. DEPENDING ON AMOUNT
OF CLEARING...MAY SEE TEMPS TOP OUT IN THE 70S IN SPOTS BOTH
DAYS...BUT WILL LEAN MORE TOWARD COOLER CONSENSUS GUIDANCE GIVEN THE
CHANCES FOR PRECIP/CLOUD COVER...WHICH HAS HIGHS IN THE MID 60S TO
70.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 132 PM EDT SUN SEP 14 2014
EXCEPT FOR SOME MVFR CIGS AT CMX EARLY THIS AFTERNOON...UNDER
RELATIVELY DRY LOW LEVELS...MAINLY VFR CONDITIONS WILL PREVAIL AT
THE TAF SITES THROUGH THE FCST PERIOD. ROACHING COLD FRONT WILL
BRING SCT -SHRA OR SPRINKLES AT SAW EARLY THIS AFTERNOON WHERE VCSH
WAS MENTIONED. SW WINDS GUSTING TO 20 KT WILL SHIFT W BEHIND THE
FRONT THIS AFTERNOON AND MAY GUST AS HIGH AS 25 KTS AT KCMX BEFORE
TAPERING OFF TOWARD EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 457 AM EDT SUN SEP 14 2014
A LOW PRES TROF OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY AS
S TO SW WINDS OF 10-20 KT SHIFT WEST ACROSS THE LAKE. THERE MAY BE
PERIODS OF SOMEWHAT HIGHER WINDS TO 25 KTS LATE MON NIGHT THRU EARLY
WED AHEAD OF AND BEHIND A COLD FRONT THAT WILL DROP S ACROSS LAKE
SUPERIOR TUE. LIGHTER WINDS WILL THEN BE THE RULE LATER WED THRU THU
HAS HIGH PRES MOVE SE ACROSS NRN ONTARIO TOWARD THE LOWER LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
348 PM CDT SUN SEP 14 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 246 PM CDT SUN SEP 14 2014
ALTHOUGH NOWHERE NEAR AS INTERESTING ON SATELLITE AS HURRICANE ODILE
IN THE ERN PAC...WATER VAPOR IMAGERY WITH RAP H5 ANALYSIS DOES SHOW
A STRONG WAVE CURRENTLY WORKING SOUTH ACROSS MANITOBA. THIS WAVE
WILL DIVE SE ACROSS NODAK AND SRN MN TONIGHT AND ACROSS CENTRAL WI
MONDAY. THIS IS A PRETTY POTENT WAVE...WITH THE NAM SHOWING THE 1.5
PV SFC /APPROXIMATE TROPOPAUSE LEVEL/ GETTING DOWN TO H5. BESIDE THE
PV ADVECTION OUT AHEAD OF THE WAVE...A FAIRLY STRONG BAND OF FGEN
WILL BE SETTING UP ACROSS SRN MN IN THE H7-H6 LAYER.
HOWEVER...CONCURRENT WITH THIS FORCING IN THE H7-H6 LAYER IS A VERY
DRY LAYER OF AIR BETWEEN H8 AND H7 THAT RAP SOUNDINGS SHOW NOW BEING
IN PLACE ACROSS THE AREA. MAJORITY OF SHORT TERM MODELS /BOTH CAMS
AND NON-CAMS/ SHOW THIS DEFORMATION BAND SETTING UP FROM RWF TO THE
SRN TWIN CITIES METRO AND OVER TO EAU. ALTHOUGH WE HAVE THAT DRY AIR
TO WORK WITH...FORCING LOOKS TO BE AROUND LONG ENOUGH TO ALLOW LIGHT
RAIN TO FALL ALONG THE LINE MENTIONED ABOVE. MAY SEE RAIN FOR
SEVERAL HOURS TONIGHT...BUT WILL BE A STRUGGLE TO EVEN GET TO A
TENTH OF AN INCH. WHAT THIS DRY AIR WILL DO IS RESULT IN A VERY
TIGHT PRECIP GRADIENT...WITH POP FORECAST AS OF 3 PM HAVING NEAR 50
POPS DOWN TOWARD LAKEVILLE...WITH NEAR ZERO BY THE TIME YOU GET TO
ANOKA.
AFTER 6Z...A STRONGER BURST OF RAIN LOOKS TO COME INTO SW MN AND
TRACK ACROSS I-90 THROUGH 12Z AND THIS IS ASSOCIATED WITH THE PV
FEATURE MOVING THROUGH. THIS AREA OF PRECIP LOOKS TO BE A BIT MORE
EFFICIENT AT PRODUCING RAIN...SO WENT WITH AN ECMWF/GFS/HPC QPF
BLEND...WHICH RESULTED ABOUT A QUARTER INCH OF RAIN FORECAST BETWEEN
MKT AND THE IOWA BORDER TONIGHT ALONG WITH CATEGORICAL POPS.
FOR TEMPERATURES...DID BOOST LOWS SOME ACROSS SRN MN...WHERE CLOUDS
WILL LIMIT THE AMOUNT OF COOLING...BUT VERY LITTLE CHANGE WAS MADE
TO THE FORECAST TOMORROW...AS SKIES LOOK TO CLEAR OUT IN THE
MORNING...WITH A BEAUTIFUL EARLY FALL DAY ENSUING THEREAFTER WITH
HIGHS IN THE UPPER 50S TO MID 60S...CLOSE TO WHAT A BLEND OF THE
BIAS CORRECTED RAW MODEL GUIDANCE GIVES YOU.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 246 PM CDT SUN SEP 14 2014
A SURFACE HIGH BUILDS IN ACROSS THE FORECAST AREA ON MONDAY AS THE
RAIN AND CLOUD COVER MOVE OUT DURING THE AFTERNOON. A DRY AND COOL
ATMOSPHERIC COLUMN IS EXPECTED TUESDAY THROUGH THURSDAY. TUESDAY
COULD STILL BE QUITE COOL AS MN/WI REMAIN ON THE BACK SIDE OF AN
850MB COLD POCKET STRETCHING EASTWARD TOWARD THE GREAT LAKES.
THERE IS A WEAK SURFACE TROUGH AND INSTABILITY POOLING ALONG A
MOISTURE AXIS STRETCHING FROM THE SOUTHERN PLAINS INTO NORTH
CENTRAL SD TUESDAY/TUESDAY NIGHT...BUT THERE DOESN`T SEEM TO BE
MUCH CONVERGENCE AT THIS TIME AND THE BOUNDARY WOULD REMAIN WELL
SOUTHWEST OF THE AREA ANYWAY. SO...ZERO POPS IT IS TUESDAY AND
WEDNESDAY. THERE IS 925-850MB WARM ADVECTION ON WEDNESDAY AND
THURSDAY...SO THERE COULD BE A LITTLE MORE WARMING THAN WHAT IS
CURRENTLY IN THE FORECAST. WHILE MONDAY AND TUESDAY SHOULD FEATURE
PLENTY OF 60S DURING THE AFTERNOON...THERE IS THE POTENTIAL FOR
LOW 70S IN MN WEDNESDAY AND THURSDAY AFTERNOON. IT ALSO LOOKS LIKE
OVERNIGHT LOWS IN THE COMING WEEK SHOULD BE WELL ABOVE THE
FREEZING MARK...SO THERE IS VERY LITTLE THREAT OF MORNING FROST
THIS COMING WEEK.
THE NEXT CHANCE FOR PRECIP AFTER MONDAY WILL HAVE TO WAIT UNTIL AT
LEAST FRIDAY WHEN BOTH THE 14.12Z GFS/ECMWF DEPICT LIGHT QPF ACROSS
THE FORECAST AREA. THE MODELS DON`T REALLY SHOW MUCH MOISTENING BELOW
700MB BEFORE SHORTWAVE ENERGY MAKES IT INTO THE EASTERN HALF OF
MN...SO MUCH OF THE FORECAST AREA MIGHT END UP WITH VERY LIGHT RAIN
OR VIRGA DURING THE DAY ON FRIDAY /OR NOTHING/.
NONETHELESS...THERE IS GOOD LOW LEVEL SOUTHWEST FLOW AND
TEMPERATURE ADVECTION DURING THE DAY WITH A MODEST INCREASE IN
INSTABILITY...ESPECIALLY IN WESTERN AND SOUTHERN MN. THE TIMING OF
THE WAVE THROUGH THE DAY ON FRIDAY AND INTO SATURDAY IS STILL
UNCERTAIN. THE 12Z ECMWF IS FASTER THAN THE GFS...AND THE GFS ALSO
DEVELOPS A WEAK SECONDARY LOW NEAR THE COLD FRONT AND SATURDAY.
THIS WOULD PROLONG THE PRECIP WELL INTO THE
WEEKEND...HOWEVER...THE LAST 4-5 RUNS OF THE GFS HAVE REALLY
LACKED CONSISTENCY. WE ARE CARRYING CHANCE POPS FOR SHOWERS WITH
EMBEDDED THUNDER FOR NOW WITH THAT THE IDEA THAT A BROKEN BAND OF
SHOWERS WILL SWING THROUGH WITH THE COLD FRONT FRIDAY NIGHT OR
SATURDAY MORNING. IF THERE IS A LESSON TO BE LEARNED OVER THE PAST
COUPLE MONTHS...IT`S THAT THE HEAVIER SHOWERS AND MORE ROBUST
THUNDERSTORMS WILL END UP SOUTH OF THE FORECAST AREA IN IOWA AND
PORTIONS OF IL AND SOUTHERN WI...WHERE THE HIGHEST INSTABILITY IS
FORECAST TO BE LOCATED. STILL SOME TIME TO WORK THIS LATE WEEK
SYSTEM OUT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1249 PM CDT SUN SEP 14 2014
COLD FRONT IN THE PROCESS OF CLEARING EAU...WITH POST FRONTAL
STRATOCU SNEAKING DOWN INTO CENTRAL MN. AXN WILL HAVE AT LEAST
A COUPLE OF HOURS OF MVFR CIGS. THESE CLOUDS MAY GET AS FAR SOUTH
AS STC...BUT NOT EXPECTING THEM ANY FARTHER SOUTH THAN THAT. BIG
QUESTION FOR TONIGHT IS HOW FAR NORTH WILL PRECIP MAKE IT. THE
COMPLICATING FACTOR IS THE DRY AIR THAT WILL EXIST BELOW THE
FORCING...BUT THE RAP/HRRR/NAM SHOW SOME LIGHT RAIN GETTING UP TO
RWF/MSP/EAU. DID INTRODUCE SOME -RA TO RWF...BUT FEEL DRY AIR WILL
BE STOUT ENOUGH WITH SFC HIGH DROPPING SOUTH TO KEEP MSP/EAU TO
REPORTING VIRGA.
KMSP...BEGINNING TO SEE INDICATIONS WITH SOME OF THE SHORT TERM
MODELS THAT RAIN MAY GET AS FAR NORTH AS MSP...BUT WE WILL HAVE A
PRETTY STRONG AND DEEP LAYER OF DRY AIR BELOW THE PRECIP THAT
SHOULD ALLOW FOR NOTHING MORE THAN VIRGA. EVEN IF PRECIP DOES
REACH THE GROUND...SAID DRY AIR WILL KEEP CIGS VFR...WHILE RATES
WILL NOT BE STRONG ENOUGH TO DROP VSBYS. OTHER THAN
THAT...CONFIDENCE IS HIGH WITH THE REMAINING ASPECTS OF THE TAF.
/OUTLOOK FOR KMSP/
TUE...VFR. WINDS SW AT 10 KTS.
WED...VFR. WINDS SSE AT 5 KTS.
THU...VFR. WINDS SE AT 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...CLF
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
113 PM CDT SUN SEP 14 2014
.UPDATE...
ISSUED AT 652 AM CDT SUN SEP 14 2014
DESPITE MID LEVEL CLOUDINESS IN AN AREA OF WEAK FRONTOGENESIS AND
DECENT ELEVATED INSTABILITY...ECHOES HAVE DECREASED ACROSS CHERRY
COUNTY THIS MORNING AND HAVE THEREFORE PULLED THEM FROM THE FCST.
OTHERWISE NO MAJOR CHANGES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CDT SUN SEP 14 2014
MAIN UPPER PV ANOMALY LOCATED ACROSS NRN ND WILL CONTINUE ITS QUICK
EWD PROGRESSION TO THE NRN GREAT LAKES REGION THROUGH THE DAY WHILE
ASSOCIATED FRONT LOSES SWD MOMENTUM AND IS PROGGED BY THE MODELS TO
STALL ACROSS NRN NEB. THIS IS IN LINE WITH CURRENT PRESSURE FIELDS
EARLY THIS MORNING AS BEST FALLS ARE OVER NRN MN AND WEAK RISES
BEHIND THE FRONT AS IT ENTERS THE NRN PORTION OF THE STATE. UNDULAR
BORE EVIDENT WITH THE FRONT CURRENTLY ON KLNX 88D INDICATING STABLE
LOW LEVELS...HOWEVER RAP ANALYSIS AND IR IMAGERY SUGGEST SMALL AREA
OF WEAK MID LEVEL FRONTOGENESIS INDICATIVE OF DEVELOPING WARM AIR
ADVECTION ACROSS NWRN FCST AREA CURRENTLY AND LIKELY TAPPING WEAK
INSTABILITY BASED ON CONVECTIVE NATURE TO CLOUDS...AND ECHOES
SHOWING UP ALOFT ON KLNX 88D. FOR THE REST OF THE AREA...VERY LITTLE
IN THE WAY OF CLOUDS ASSOCIATED WITH THE FRONT WHICH IS EVIDENCE OF
ITS KATABATIC NATURE WITH 0.5KM/1KM AND 700 MB VWP WINDS FROM AREA
RADARS AND RAP SHORT TERM FCST SOUNDINGS SHOWING NWRLY WINDS AHEAD
OF THE FRONT. HAVE INCLUDED SPRINKLES EARLY THIS MORNING BASED ON
RADAR TRENDS MENTIONED ABOVE.
AS UPPER PV ANOMALY AND ASSOCIATED UPPER LOW MOVES INTO NRN MN THIS
MORNING...MID AND UPPER FLOW BECOMES ZONAL ACROSS THE CENTRAL
ROCKIES AND HIGH PLAINS. IN RESPONSE...MID LEVEL WINDS BECOME SWRLY
WHICH WILL ADVECT THE EML EWD OVER THE EWD ADVANCING DRYLINE ACROSS
ERN CO...AS LOWER LEVEL WINDS BACK AND BECOME S/SERLY DURING THE
AFTERNOON. NAM PROGS SFC DEW POINTS INTO THE MID 50S ACROSS SWRN
NEB...HOWEVER THE AFOREMENTIONED EML DEVELOPS A SIGNIFICANT CAP EAST
OF THE DRYLINE IN SWRN NEB DURING THE AFTERNOON HOURS. SCT/BKN CLOUD
COVER IS EXPECTED EAST OF THE DRYLINE AS WELL WHICH WILL BE EVIDENCE
OF THE HIGHER LOW LEVEL THETA E AND HIGHER CAPE. HOWEVER...DESPITE
THE NEXT APPROACHING UPPER PV ANOMALY AND STALLED SFC BOUNDARY
ACROSS THE NRN PORTION OF THE STATE...AND THE PREVIOUSLY MENTION
HIGHER CAPE AND DECENT SHEAR...THE CAP IS EXPECTED TO BE TOO STRONG
TO ALLOW CONVECTIVE INITIATION DURING THE AFTERNOON IN WRN NEB.
HOWEVER...CONVECTION ALLOWING MODELS /CAMS/ ARE QUICKER TO DEVELOP
STORMS ACROSS NRN NEB INTO SERN SD BY EVENING WHICH WILL BE CLOSER
TO MAIN UPPER LEVEL SUPPORT AND SFC WARM FRONT SO PRECIP CHANCES
WILL BE RETAINED IN THE NERN PORTION OF THE FCST AREA...THOUGH MAY
BE PUSHED BACK IN TIME A LITTLE.
NEXT SIGNIFICANT UPPER PV ANOMALY AND ASSOCIATED UPPER LOW WILL MOVE
INTO THE NRN PLAINS THIS EVENING AND SUNDAY NIGHT. THIS WILL GIVE A
NUDGE TO THE STALLED SFC BOUNDARY AND WILL MOVE IT SWD
SOMEWHAT...BUT THE HIGH PLAINS NOCTURNAL LOW LEVEL JET WILL DEVELOP
AS DRIER AIR ACROSS THE HIGHER ELEVATIONS FURTHER WEST COOLS RAPIDLY
AFTER SUNSET...BUT ALSO PARTLY IN RESPONSE TO THE LOWERING HEIGHTS
ACROSS THE NRN PLAINS. THIS LIFT WILL BE ABLE TO TAP THE ELEVATED
INSTABILITY STILL RESIDING ACROSS SWRN NEBR TO DEVELOP THUNDERSTORMS
OVERNIGHT SUNDAY NIGHT AS THE FRONT SLOWLY CONTINUES TO SAG ACROSS
THE REMAINDER OF THE STATE. THOUGH THE NAM SUPPORTS PRECIP IN THE
SWRN PORTION OF THE STATE OVERNIGHT...CAMS FOCUS MOST OF THE PRECIP
ALONG THE COLD FRONT IN NRN NEB.
AS FOR TEMPERATURES...DESPITE DEVELOPING CLOUD COVER DURING THE
AFTERNOON IN THE SW...TEMPS WILL BE MUCH WARMER WITH INCREASING SRLY
WINDS BUT WILL BE SLIGHTLY COOLER ACROSS THE NORTH AS WINDS BECOME
ERLY NORTH OF THE WARM FRONT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 342 AM CDT SUN SEP 14 2014
QUASI-ZONAL UPPER TROPOSPHERIC FLOW TO PREVAIL BEHIND A PASSING
NORTHERN PLAINS WAVE EARLY IN THE EXTENDED...BUT WILL EVENTUALLY
GIVE WAY TO NORTHWESTERLY AS A WESTERN CONUS RIDGE BUILDS EAST. AS
A RESULT A GENERAL LACK OF OMEGA IS ANTICIPATED ATOP MUCH OF THE
FORECAST AREA THROUGH TUESDAY AFTERNOON...WITH THE MODELS
PROJECTING NO ATMOSPHERIC DISTURBANCES IMPACTING THE REGION.
TUESDAY EVENING INTO WEDNESDAY...THE OPERATIONAL MODELS /GFS
INITIALLY...THEN ECMWF WEDNESDAY MORNING/ GENERATES MEASURABLE QPF
ACROSS SOUTHEASTERN PORTIONS OF THE CWA...THE MODELS ARE KEYING ON
SUFFICIENT THERMAL ADVECTION/UPGLIDE IN THE 305-310K SFC FOR
PRECIPITATION PRODUCTION. DESPITE THIS...DECIDED TO LEAVE QPF OUT
OF THE FORECAST AS PROXIMITY AND BUFR SOUNDINGS SUGGEST A MOISTURE
CHALLENGED ATMOSPHERE ABOVE THE BOUNDARY LAYER WITH THE GFS
SHOWING SIGNIFICANT DRY MID LEVELS. WITH THIS IN MIND...FELT THAT
POPS WILL BE ISOLATED AT BEST IN COVERAGE WITH QPF AMOUNTS LIGHT.
IF SHOWERS/STORMS ARE TO GO...SOUTHEASTERN PORTIONS OF THE CWA
OVERNIGHT TUESDAY INTO EARLY WEDNESDAY WOULD BE THE MOST LIKELY OF
LOCATIONS. ADDITIONAL THERMAL ADVECTION INDUCED STORMS ARE SHOWN
WEDNESDAY NIGHT INTO THURSDAY...BUT MOSTLY REMOVED /SOUTH AND
EAST/ FROM OUR CWA. CR ALLBLEND PULLED ALL MENTION OF QPF OUT OF
OUR CWA DURING THIS TIME PERIOD...WHICH IS FINE FOR NOW. UPPER
PATTERN UNDERGOES A CHANGE LATE IN THE WEEK WITH THE APPROACH OF A
WESTERN CONUS TROUGH AND ATTENDANT COLD FRONT PASSAGE. THE
TROUGH/COLD FRONT WILL SUPPRESS THE RIDGE EAST OF THE FORECAST
AREA LATE WEEK AND PROVIDE FOR PRECIPITATION. THE GFS IN
COMPARISON TO THE EC REMAINS MUCH STRONGER WITH THIS LATE WEEK
TROUGH AND MORE FAVORABLE FOR WIDESPREAD SHOWERS/STORMS. THE CR
ALLBLEND PROCEDURE RAMPS UP POPS STARTING FRIDAY...WITH POPS
MAXIMIZED NEAR 40 PERCENT FOR SATURDAY AND INTO EARLY SUNDAY. TO
BE HONEST...REALLY NOT TOO KEEN ON 4 PERIODS OF QPF THAT IS
ASSOCIATED WITH THE PASSAGE OF THIS DISTURBANCE/FRONT...ESPECIALLY
IN A SOMEWHAT PROGRESSIVE PATTERN...BUT WILL LEAVE THE PROCEDURE
UNCHANGED DUE TO THE USUAL TIMING/STRENGTH DIFFERENCES SEEN THIS
FAR OUT.
DRIZZLE REPLACED THE SLIGHT CHANCE MENTION OF QPF FROM 12-15Z THIS
MONDAY AS PROXIMITY SOUNDINGS REVEAL DRYING ALOFT...BUT A SATURATED
BL WITH WEAK LIFT. THIS DRIZZLE SHOULD NOT LAST LONG AS PROXIMITY
SOUNDINGS REVEAL RAPID BL DRYING BEHIND THE FRONT. WILL ALSO NEED
TO MONITOR THE RETURN OF LOW LEVEL MOISTURE EARLY TUESDAY AS SURFACE
HIGH PRESSURE BUILDS EAST OF THE MISSOURI VALLEY. NAM12 0.5AGL RH
WOULD INDICATE A SIGHT POTENTIAL OF FOG ACROSS SOUTHWEST
NEBRASKA...BUT CONFIDENCE WAS NOT SUFFICIENT TO INCLUDE THE MENTION
WITH THIS FORECAST.
RETURN SOUTHERLY FLOW AND RESULTANT THERMAL ADVECTION WILL PROMOTE A
WARMING TREND MONDAY THROUGH MID-LATE WEEK...WIDESPREAD HIGHS IN THE
80S BY THURSDAY ARE ANTICIPATED. WARMEST READINGS WILL BE ACROSS
OUR WEST EACH DAY WITH A GREATER INFLUENCE FROM THE UPPER TROPOSPHERIC
RIDGE. OVERNIGHT LOWS WILL BENEFIT AS WELL...RISING FROM THE 40S
MONDAY MORNING...TO POSSIBLY THE 50S TO 60S BY WEEKS END.
TEMPERATURES COOL LATE WEEK BEHIND THE FRONT...BUT AT THAT...NOT
ANTICIPATING WHAT WE SAW A FEW DAYS AGO...NO FROST OR FREEZE
ISSUES ARE EXPECTED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 112 PM CDT SUN SEP 14 2014
TROUGH MOVING ACROSS THE AREA THIS EVENING LIKELY TO SPARK SOME
THUNDERSTORMS. FAVORABLE MODEL SOUNDINGS SUPPORT IMPACT OVERNIGHT
TO KLBF HOWEVER STILL HAVE SOME UNCERTAINTY FOR KVTN. WILL
CONTINUE THE PROB30 FOR KLBF...WITH NO MENTION YET FOR KVTN...AND
WILL MONITOR FOR POSSIBLE AMENDMENT. LATER TONIGHT...BEHIND
THUNDERSTORM ACTIVITY...EXPECT SOME STRATUS TO DEVELOP WITH MVFR
CIGS...POSSIBLY IFR. ACTIVITY WILL BE ERODE FROM THE NW AS HIGH
PRESSURE BUILDS SOUTH.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JWS
SHORT TERM...JWS
LONG TERM...JACOBS
AVIATION...MASEK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
600 PM CDT SUN SEP 14 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 336 PM CDT SUN SEP 14 2014
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF THE U.S. INTO BRITISH
CLIMB...WHILE DEEP TROUGHING ENCOMPASSED MUCH OF CENTRAL CANADA
INTO THE NORTHERN TIER OF THE CENTRAL U.S.. WITHIN THIS DEEP
TROUGH...THE TWO SHORTWAVE TROUGHS OF INTEREST WERE OVER LAKE
SUPERIOR AND IN SOUTHWEST SASKATCHEWAN. THE LAKE SUPERIOR
SHORTWAVE TROUGH WAS DRAGGING A COLD FRONT THROUGH THE FORECAST
AREA TODAY...BUT WITH LITTLE FAN FARE AS THE FRONT HAS BEEN
MOISTURE STARVED. 12Z SOUNDINGS FROM MPX AND ESPECIALLY GRB
REFLECT THE LACK OF MOISTURE. ADDITIONALLY...THE FRONT HAS BEEN
BASICALLY TURNING INTO A WIND SHIFT WITH 925MB TEMPS RUNNING
AROUND 10C ACROSS THE FORECAST AREA PER LATEST RAP ANALYSIS. THESE
TEMPS...BEING 2-4C WARMER THAN YESTERDAY...COMBINED WITH FULL SUN
HAS ALLOWED READINGS TO CLIMB INTO THE 60S. FARTHER TO THE
WEST...A SECONDARY COLD FRONT WAS DROPPING THROUGH NORTHWEST MN
WITH TEMPERATURES IN THE 50S AND SOME STRATUS IN ITS WAKE. AHEAD
OF THE FRONT...A STREAM OF MID CLOUDS WERE EXPANDING ACROSS
NORTHERN SOUTH DAKOTA INTO SOUTHERN MN...ASSOCIATED WITH MID-LEVEL
FRONTOGENESIS DOWNSTREAM OF THE SASKATCHEWAN SHORTWAVE. A 100 KT
JET STREAK FROM CENTRAL MN INTO UPPER MI AT 250MB IS ALSO
SUPPORTING THE MID CLOUDS.
MODELS ARE IN GOOD AGREEMENT TAKING THE SHORTWAVE OVER SOUTHWEST
SASKATCHEWAN THROUGH SOUTHWEST MN MONDAY MORNING AND ACROSS THE
FORECAST AREA MONDAY AFTERNOON. ADDITIONALLY...MODELS CONTINUE TO
SUGGEST THE SHORTWAVE WILL STRENGTHEN AS IT APPROACHES THE FORECAST
AREA...WHICH IN TURN INDUCES AN INCREASE IN THE UPPER JET STREAK
DOWNSTREAM AS WELL AS THE MID LEVEL FRONTOGENESIS. IN FACT...BY 12Z
MONDAY...THE SOUTHERN PORTION OF THE FORECAST AREA LIES IN A VERY
FAVORABLE DYNAMIC SITUATION...WITH A RIGHT ENTRANCE REGION OF THE
UPPER JET...DPVA AHEAD OF THE SHORTWAVE AND A FAIRLY STRONG COUPLET
OF MID LEVEL FRONTOGENESIS AND FRONTOLYSIS.
THE OVERALL BIG PROBLEM FOR PRECIPITATION IS MOISTURE. MOISTURE
TRANSPORT AHEAD OF THE SHORTWAVE WILL HELP PULL HIGHER PRECIPITABLE
WATER FROM THE SOUTHERN PLAINS TOWARDS THE REGION TONIGHT.
HOWEVER...CONVECTION SHOULD BREAK OUT ON THE NOSE OF THIS TRANSPORT
ACROSS NORTHERN MO...PUTTING A WALL UP ON THE MOISTURE RETURN.
STILL...PRECIPITABLE WATER SHOULD CLIMB UP TO ABOUT 1 INCH WHICH
WITH THE FORCING SHOULD BE ABLE TO SQUEEZE OUT SOME RAIN. DRY SUB-
CLOUD AIR MAY HINDER AMOUNTS TO SOME DEGREE.
TIMING WISE...SOME LIGHT RAIN COULD BREAK OUT AS EARLY AS THIS
EVENING...BUT THE BETTER CHANCE FOR RAIN COMES AFTER MIDNIGHT INTO
MONDAY MORNING. LOCATIONS AROUND AND SOUTH OF I-90 APPEAR TO HAVE
THE BEST CHANCE TO SEE RAIN. PRECIPITATION WILL DIMINISH RAPIDLY
MONDAY AFTERNOON AS THE SHORTWAVE MOVES THROUGH...WITH SKIES
CLEARING TOO.
REGARDING TEMPERATURES. THE SECONDARY COLD FRONT LOOKS TO PUSH
THROUGH THE FORECAST AREA TONIGHT...SENDING READINGS DOWN INTO THE
40S TO NEAR 50. IF THE CLOUDS STAYED IN ALL DAY MONDAY...HIGHS WOULD
STRUGGLE TO GET ABOVE THE MID 50S. HOWEVER...CONFIDENCE IS HIGH FOR
SUNSHINE IN THE AFTERNOON...WHICH SHOULD MUCH OF THE FORECAST AREA
CLIMB INTO THE UPPER 50S TO LOW 60S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 336 PM CDT SUN SEP 14 2014
FROM LATE MONDAY NIGHT AND TUESDAY MORNING...CANADIAN HIGH
PRESSURE WILL BUILD ACROSS THE AREA. THIS HIGH WILL PROVIDE CLEAR
SKIES ACROSS THE AREA. WITH THE CENTER OF THIS HIGH PASSING TO
SOUTHWEST...THERE WILL BE A SHALLOW LAYER OF LIGHT WINDS BELOW 950
MB. MEANWHILE THE WINDS WILL BE IN THE 10 TO 15 KNOT RANGE BETWEEN
950 AND 800 MB. THESE WINDS MAY HINDER THE DEVELOPMENT OF FOG AND
FROST. HOWEVER IS A STRONG SHALLOW NOCTURNAL INVERSION CAN
DEVELOPMENT CANNOT RULE OUT EITHER FROM OCCURRING...SO INCLUDED A
MENTION OF PATCHY VALLEY FOG IN THE MISSISSIPPI TRIBUTARIES AND IN
CENTRAL WISCONSIN. IN ADDITION WITH TEMPERATURES IN THE MID 30S
ACROSS PARTS OF WESTERN WISCONSIN... THERE MAY BE PATCHY FROST
TOO.
FROM LATE TUESDAY NIGHT AND WEDNESDAY MORNING...THERE WILL BE A
DEEPER LAYER OF LIGHT WINDS /UP TO 800 MB/. THE NAM CONTINUES TO
PRODUCE A VERY SHALLOW SATURATED LAYER. MEANWHILE THE GFS DOES NOT
PRODUCE THIS. WITH THE LIGHT WINDS AND COOL TEMPERATURES OVER THE
WARM RIVER WATERS...EXPECT THAT THERE WILL PATCHY TO AREAS OF FOG
IN THE RIVER VALLEYS AND OVER THE CRANBERRY BOGS OF CENTRAL
WISCONSIN. DUE TO THIS INCLUDED...IT IN THE FORECAST GRIDS.
ON WEDNESDAY...A BACK DOOR COLD FRONT MOVES THROUGH THE FORECAST
AREA. THE GEM PRODUCES SOME LIGHT PRECIPITATION ALONG AND NORTH OF
INTERSTATE 94. MEANWHILE THE ECMWF AND GFS KEEPS THE AREA DRY.
WITH THE BUFKIT SOUNDINGS SHOWING ONLY ABOUT 50 MB OF MOISTURE
BETWEEN 800 AND 850 MB...KEPT THE FORECAST DRY.
FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY MORNING...IT LOOKS LIKE
THERE WILL BE YET ANOTHER NIGHT FOR THE POTENTIAL OF VALLEY FOG AS
THE LIGHT WINDS ASCEND UP TO 700 MB. HOWEVER WITH THE WINDS
INCREASING INTO THE 10 TO 15 KNOTS LATE IN THE NIGHT...WE MAY END
UP WITH FOG DEVELOPING EARLIER IN THE NIGHT AND THEN BECOMING A
LAYER OF STRATUS AS THE LOW LEVEL WINDS INCREASE. DUE TO THIS
UNCERTAINTY...KEPT THE MENTION OF FOG OUT OF THE FORECAST GRIDS
FOR NOW.
FRIDAY INTO FRIDAY EVENING IS STARTING TO LOOK MORE INTERESTING AS
BOTH MODELS ARE STARTING TO CONVERGE ON A SOLUTION. A WARM FRONT
MOVES THROUGH THE AREA DURING THE MORNING AND THEN A COLD FRONT
MOVES INTO THE AREA ON FRIDAY EVENING. AS THE AREA MOVES INTO THE
WARM SECTOR OF THIS SYSTEM...THE ML CAPES CLIMB INTO THE 1500 TO
2500 J/KG RANGE. IN ADDITION...THE 0-6 KM SHEAR CLIMBS ABOVE 40
KNOTS. THIS COULD POTENTIALLY RESULT IN THE DEVELOPMENT OF SUPER
CELL THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS BEING THE
PRIMARY THREATS.
ON SATURDAY...THE 14.00Z MODELS SHOW A SURFACE LOW MOVING THROUGH
THE AREA. THIS KEEPS THE 0 TO 6 KM SHEAR ABOVE 45 KNOTS. WITH ML
CAPES IN THE 1000 TO 1500 J/KG...THERE COULD BE THE POTENTIAL FOR
SUPER CELL THUNDERSTORMS ACROSS NORTHEAST IOWA...AND SOUTHWEST AND
CENTRAL WISCONSIN. WITH 0-1 KM CAPES OVER 150 J/KG...LCL HEIGHTS
LESS THAN 2K FEET...AND 0-1 KM HELICITY OVER 100 M2/S2 ALONG THE
WARM FRONT WHICH IS LOCATED NEAR THE INTERSTATE 90 CORRIDOR IN
WISCONSIN...COULD NOT RULE THE POSSIBILITY OF ISOLATED TORNADOES
TO GO ALONG WITH THE THREAT FOR LARGE HAIL AND DAMAGING WINDS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 600 PM CDT SUN SEP 14 2014
RAIN CONTINUES TO DEVELOP AND EXPAND EASTWARD ALONG A WEST-EAST
RUNNING FRONTAL BOUNDARY...LAID UP ACROSS SOUTHERN MN INTO WESTERN
WI. THE PCPN IS FALLING OUT OF MID LEVEL CLOUDS CURRENTLY. AS AN
UPPER LEVEL SHORTWAVE STARTS TO PUSH IN FROM THE NORTHERN PLAINS
OVERNIGHT...THE PCPN WILL BECOME MORE WIDESPREAD AND START TO SINK
SOUTH. LOW LEVEL RH INCREASES...PER BUFKIT SOUNDINGS...AND
CONDITIONS LOOK FAVORABLE FOR A DROP INTO MVFR FOR A FEW HOURS.
MESO MODELS TAKE THIS SYSTEM ACROSS THE REGION DURING THE
AFTERNOON...EXITING BY EARLY EVENING. PCPN SHOULD FOLLOW
SUIT...MOVING EAST/SOUTHEAST OF THE TAF SITES BETWEEN 18-21Z.
SUBSIDENCE POST THE SHORTWAVE ALONG WITH A SFC HIGH INFLUENCING FROM
THE CENTRAL PLAINS SHOULD CLEAR SKIES LATER MON AFTERNOON/EARLY
EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....BOYNE
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
337 PM CDT SUN SEP 14 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 336 PM CDT SUN SEP 14 2014
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF THE U.S. INTO BRITISH
CLIMB...WHILE DEEP TROUGHING ENCOMPASSED MUCH OF CENTRAL CANADA
INTO THE NORTHERN TIER OF THE CENTRAL U.S.. WITHIN THIS DEEP
TROUGH...THE TWO SHORTWAVE TROUGHS OF INTEREST WERE OVER LAKE
SUPERIOR AND IN SOUTHWEST SASKATCHEWAN. THE LAKE SUPERIOR
SHORTWAVE TROUGH WAS DRAGGING A COLD FRONT THROUGH THE FORECAST
AREA TODAY...BUT WITH LITTLE FAN FARE AS THE FRONT HAS BEEN
MOISTURE STARVED. 12Z SOUNDINGS FROM MPX AND ESPECIALLY GRB
REFLECT THE LACK OF MOISTURE. ADDITIONALLY...THE FRONT HAS BEEN
BASICALLY TURNING INTO A WIND SHIFT WITH 925MB TEMPS RUNNING
AROUND 10C ACROSS THE FORECAST AREA PER LATEST RAP ANALYSIS. THESE
TEMPS...BEING 2-4C WARMER THAN YESTERDAY...COMBINED WITH FULL SUN
HAS ALLOWED READINGS TO CLIMB INTO THE 60S. FARTHER TO THE
WEST...A SECONDARY COLD FRONT WAS DROPPING THROUGH NORTHWEST MN
WITH TEMPERATURES IN THE 50S AND SOME STRATUS IN ITS WAKE. AHEAD
OF THE FRONT...A STREAM OF MID CLOUDS WERE EXPANDING ACROSS
NORTHERN SOUTH DAKOTA INTO SOUTHERN MN...ASSOCIATED WITH MID-LEVEL
FRONTOGENESIS DOWNSTREAM OF THE SASKATCHEWAN SHORTWAVE. A 100 KT
JET STREAK FROM CENTRAL MN INTO UPPER MI AT 250MB IS ALSO
SUPPORTING THE MID CLOUDS.
MODELS ARE IN GOOD AGREEMENT TAKING THE SHORTWAVE OVER SOUTHWEST
SASKATCHEWAN THROUGH SOUTHWEST MN MONDAY MORNING AND ACROSS THE
FORECAST AREA MONDAY AFTERNOON. ADDITIONALLY...MODELS CONTINUE TO
SUGGEST THE SHORTWAVE WILL STRENGTHEN AS IT APPROACHES THE FORECAST
AREA...WHICH IN TURN INDUCES AN INCREASE IN THE UPPER JET STREAK
DOWNSTREAM AS WELL AS THE MID LEVEL FRONTOGENESIS. IN FACT...BY 12Z
MONDAY...THE SOUTHERN PORTION OF THE FORECAST AREA LIES IN A VERY
FAVORABLE DYNAMIC SITUATION...WITH A RIGHT ENTRANCE REGION OF THE
UPPER JET...DPVA AHEAD OF THE SHORTWAVE AND A FAIRLY STRONG COUPLET
OF MID LEVEL FRONTOGENESIS AND FRONTOLYSIS.
THE OVERALL BIG PROBLEM FOR PRECIPITATION IS MOISTURE. MOISTURE
TRANSPORT AHEAD OF THE SHORTWAVE WILL HELP PULL HIGHER PRECIPITABLE
WATER FROM THE SOUTHERN PLAINS TOWARDS THE REGION TONIGHT.
HOWEVER...CONVECTION SHOULD BREAK OUT ON THE NOSE OF THIS TRANSPORT
ACROSS NORTHERN MO...PUTTING A WALL UP ON THE MOISTURE RETURN.
STILL...PRECIPITABLE WATER SHOULD CLIMB UP TO ABOUT 1 INCH WHICH
WITH THE FORCING SHOULD BE ABLE TO SQUEEZE OUT SOME RAIN. DRY SUB-
CLOUD AIR MAY HINDER AMOUNTS TO SOME DEGREE.
TIMING WISE...SOME LIGHT RAIN COULD BREAK OUT AS EARLY AS THIS
EVENING...BUT THE BETTER CHANCE FOR RAIN COMES AFTER MIDNIGHT INTO
MONDAY MORNING. LOCATIONS AROUND AND SOUTH OF I-90 APPEAR TO HAVE
THE BEST CHANCE TO SEE RAIN. PRECIPITATION WILL DIMINISH RAPIDLY
MONDAY AFTERNOON AS THE SHORTWAVE MOVES THROUGH...WITH SKIES
CLEARING TOO.
REGARDING TEMPERATURES. THE SECONDARY COLD FRONT LOOKS TO PUSH
THROUGH THE FORECAST AREA TONIGHT...SENDING READINGS DOWN INTO THE
40S TO NEAR 50. IF THE CLOUDS STAYED IN ALL DAY MONDAY...HIGHS WOULD
STRUGGLE TO GET ABOVE THE MID 50S. HOWEVER...CONFIDENCE IS HIGH FOR
SUNSHINE IN THE AFTERNOON...WHICH SHOULD MUCH OF THE FORECAST AREA
CLIMB INTO THE UPPER 50S TO LOW 60S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 336 PM CDT SUN SEP 14 2014
FROM LATE MONDAY NIGHT AND TUESDAY MORNING...CANADIAN HIGH
PRESSURE WILL BUILD ACROSS THE AREA. THIS HIGH WILL PROVIDE CLEAR
SKIES ACROSS THE AREA. WITH THE CENTER OF THIS HIGH PASSING TO
SOUTHWEST...THERE WILL BE A SHALLOW LAYER OF LIGHT WINDS BELOW 950
MB. MEANWHILE THE WINDS WILL BE IN THE 10 TO 15 KNOT RANGE BETWEEN
950 AND 800 MB. THESE WINDS MAY HINDER THE DEVELOPMENT OF FOG AND
FROST. HOWEVER IS A STRONG SHALLOW NOCTURNAL INVERSION CAN
DEVELOPMENT CANNOT RULE OUT EITHER FROM OCCURRING...SO INCLUDED A
MENTION OF PATCHY VALLEY FOG IN THE MISSISSIPPI TRIBUTARIES AND IN
CENTRAL WISCONSIN. IN ADDITION WITH TEMPERATURES IN THE MID 30S
ACROSS PARTS OF WESTERN WISCONSIN... THERE MAY BE PATCHY FROST
TOO.
FROM LATE TUESDAY NIGHT AND WEDNESDAY MORNING...THERE WILL BE A
DEEPER LAYER OF LIGHT WINDS /UP TO 800 MB/. THE NAM CONTINUES TO
PRODUCE A VERY SHALLOW SATURATED LAYER. MEANWHILE THE GFS DOES NOT
PRODUCE THIS. WITH THE LIGHT WINDS AND COOL TEMPERATURES OVER THE
WARM RIVER WATERS...EXPECT THAT THERE WILL PATCHY TO AREAS OF FOG
IN THE RIVER VALLEYS AND OVER THE CRANBERRY BOGS OF CENTRAL
WISCONSIN. DUE TO THIS INCLUDED...IT IN THE FORECAST GRIDS.
ON WEDNESDAY...A BACK DOOR COLD FRONT MOVES THROUGH THE FORECAST
AREA. THE GEM PRODUCES SOME LIGHT PRECIPITATION ALONG AND NORTH OF
INTERSTATE 94. MEANWHILE THE ECMWF AND GFS KEEPS THE AREA DRY.
WITH THE BUFKIT SOUNDINGS SHOWING ONLY ABOUT 50 MB OF MOISTURE
BETWEEN 800 AND 850 MB...KEPT THE FORECAST DRY.
FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY MORNING...IT LOOKS LIKE
THERE WILL BE YET ANOTHER NIGHT FOR THE POTENTIAL OF VALLEY FOG AS
THE LIGHT WINDS ASCEND UP TO 700 MB. HOWEVER WITH THE WINDS
INCREASING INTO THE 10 TO 15 KNOTS LATE IN THE NIGHT...WE MAY END
UP WITH FOG DEVELOPING EARLIER IN THE NIGHT AND THEN BECOMING A
LAYER OF STRATUS AS THE LOW LEVEL WINDS INCREASE. DUE TO THIS
UNCERTAINTY...KEPT THE MENTION OF FOG OUT OF THE FORECAST GRIDS
FOR NOW.
FRIDAY INTO FRIDAY EVENING IS STARTING TO LOOK MORE INTERESTING AS
BOTH MODELS ARE STARTING TO CONVERGE ON A SOLUTION. A WARM FRONT
MOVES THROUGH THE AREA DURING THE MORNING AND THEN A COLD FRONT
MOVES INTO THE AREA ON FRIDAY EVENING. AS THE AREA MOVES INTO THE
WARM SECTOR OF THIS SYSTEM...THE ML CAPES CLIMB INTO THE 1500 TO
2500 J/KG RANGE. IN ADDITION...THE 0-6 KM SHEAR CLIMBS ABOVE 40
KNOTS. THIS COULD POTENTIALLY RESULT IN THE DEVELOPMENT OF SUPER
CELL THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS BEING THE
PRIMARY THREATS.
ON SATURDAY...THE 14.00Z MODELS SHOW A SURFACE LOW MOVING THROUGH
THE AREA. THIS KEEPS THE 0 TO 6 KM SHEAR ABOVE 45 KNOTS. WITH ML
CAPES IN THE 1000 TO 1500 J/KG...THERE COULD BE THE POTENTIAL FOR
SUPER CELL THUNDERSTORMS ACROSS NORTHEAST IOWA...AND SOUTHWEST AND
CENTRAL WISCONSIN. WITH 0-1 KM CAPES OVER 150 J/KG...LCL HEIGHTS
LESS THAN 2K FEET...AND 0-1 KM HELICITY OVER 100 M2/S2 ALONG THE
WARM FRONT WHICH IS LOCATED NEAR THE INTERSTATE 90 CORRIDOR IN
WISCONSIN...COULD NOT RULE THE POSSIBILITY OF ISOLATED TORNADOES
TO GO ALONG WITH THE THREAT FOR LARGE HAIL AND DAMAGING WINDS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1237 PM CDT SUN SEP 14 2014
VFR CONDITIONS LOOK TO DOMINATE THROUGH MUCH OF TONIGHT...DESPITE
THE PASSAGE OF TWO COLD FRONTS. THIS IS DUE TO PLENTY OF DRY AIR.
HOWEVER...AFTER MIDNIGHT...A BAND OF RAIN LOOKS TO SET UP BEHIND
THE PASSAGE OF THE SECOND COLD FRONT. THIS RAIN SHOULD GRADUALLY
LOWER CEILINGS...AND THERE ARE SOME SIGNS THAT A MVFR CEILING
COULD DEVELOP FOR A TIME MONDAY MORNING. INCLUDED A TEMPO GROUP
FOR THIS. NO VISIBILITIES RESTRICTIONS ARE EXPECTED DUE TO THE
AFOREMENTIONED DRY AIR AND LIGHT RAIN RATES. REGARDING
WINDS...GUSTS OF 20-25 KT HAVE DEVELOPED THIS MORNING. THESE
SHOULD CONTINUE UNTIL THE COMBINATION OF ALTOSTRATUS MOVING IN
LATE IN THE DAY AND LOSS OF DAYTIME HEATING STOP THE MIXING. WINDS
WILL DIMINISH FURTHER THIS EVENING WITH A SWITCH TO THE NORTHWEST
IN THE WAKE OF THE SECOND COLD FRONT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...BOYNE
AVIATION...AJ