Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/03/14
AREA FORECAST DISCUSSION
NWS PUEBLO CO
311 PM MDT MON SEP 1 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 240 PM MDT MON SEP 1 2014
MAIN NEAR/SHORT-TERM METEOROLOGICAL ISSUES ARE
TEMPERATURES...LOCALIZED GUSTY WINDS AT TIMES AND LOCALIZED LOW-
GRADE POPS.
CWFA EXPERIENCING NEAR SEASONAL SEPTEMBER AFTERNOON TEMPERATURES IN
COMBINATION WITH GENERALLY SUNNY SKIES...ALTHOUGH SOME VARIABLE
CLOUDS NOTED OVER PRIMARILY HIGHER TERRAIN LOCATIONS.
IN ADDITION...WIND GUSTS EXCEEDING 30 MPH AT TIMES HAVE BEEN
OBSERVED OVER THE MOUNTAINS OF CHAFFEE COUNTY. RECENT RADAR RETURNS
INDICATE SHOWERS AND THUNDERSTORMS NEARING FAR NORTHEASTERN
COLORADO...WELL NORTH OF OUR CWFA.
LATEST COMPUTER SIMULATIONS...REAL-TIME DATA AND FORECAST MODEL
SOUNDINGS INDICATE THAT GENERALLY DRY CONDITIONS SHOULD CONTINUE
OVER THE MAJORITY OF THE FORECAST DISTRICT FROM LATE THIS AFTERNOON
INTO TUESDAY AFTERNOON...ALTHOUGH RECENT HRRR MODEL DATA SUGGESTS
THAT SHOWERS AND THUNDERSTORMS MAY THREATEN PORTIONS OF NORTHERN EL
PASO AND KIOWA COUNTIES AS WELL AS SECTIONS OF LAS ANIMAS AND BACA
COUNTIES FROM LATER THIS AFTERNOON INTO THIS EVENING.
FOR TUESDAY...THE HIGHEST PROBABILITY OF ISOLATED SHOWER AND
THUNDERSTORM ACTIVITY SHOULD BE NOTED OVER WESTERN HIGHER TERRAIN
LOCATIONS...PRIMARILY DURING THE AFTERNOON AND EVENING HOURS.
GUSTY...PRIMARILY HIGHER TERRAIN WINDS ARE ALSO ANTICIPATED AT TIMES
FROM LATER THIS AFTERNOON INTO TUESDAY WHILE ABOVE SEASONAL EARLY
SEPTEMBER AFTERNOON TEMPERATURES ARE PROJECTED TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 240 PM MDT MON SEP 1 2014
...HOT WITH LOW THUNDERSTORM CHANCES THROUGH EARLY THURSDAY THEN
COOLER WITH INCREASING THUNDERSTORM CHANCES...
TUESDAY EVENING INTO EARLY THURSDAY...THE AIR MASS OVER THE REGION
WILL BE QUITE WARM AND THE THUNDERSTORM CHANCES WILL BE LOW. COULD
BE SOME SPOTTY DRY THUNDERSTORMS AROUND TUESDAY EVENING...MAINLY
OVER THE MOUNTAINS. THEN...WEDNESDAY AFTERNOON...COULD BE SOME
SPOTTY DRY LINE ACTIVITY ACROSS THE FAR SOUTHEAST PLAINS. MODELS
HAVE BEEN BACK AND FORTH ON THIS SO CONFIDENCE IS A LITTLE LOW BUT
THE POSSIBILITY REMAINS ALIVE.
ON THURSDAY...THINGS START TO TRANSITION TO A COOLER...WETTER
PATTERN. MODELS HAVE BEEN PRETTY CONSISTENT ON THIS SO CONFIDENCE
IS INCREASING. IT STARTS WITH THE ARRIVAL OF A COLD FRONT THROUGH
THE EASTERN PLAINS THURSDAY AFTERNOON. THE FRONT PUSHES INTO THE
REGION AS THE RESULT OF AN UPPER DISTURBANCE MOVING THROUGH THE
NORTHERN ROCKIES AND PLAINS. AS THE FRONT MOVES IN...MOIST UPSLOPE
WINDS BEHIND THE FRONT GRADUALLY FIRE THUNDERSTORMS OVER AND NEAR
THE MOUNTAINS IN THE AFTERNOON...SOME OF WHICH WORK EAST ACROSS THE
PLAINS BY LATE IN THE DAY. WITH ADDED MOISTURE IN THE AIR AND
UPSLOPE WINDS...THE THREAT FOR STRONG STORMS WILL INCREASE THIS DAY.
FRIDAY THROUGH MONDAY...WE COULD BE DEALING WITH SOME RICH
SUBTROPICAL MOISTURE AT TIMES...JUST DEPENDING ON HOW THINGS TRACK
OVER THE NEXT FEW DAYS. RIGHT NOW...INDICATIONS ARE THAT FRIDAY AND
SATURDAY COULD BOTH BE PRETTY WET OVER THE REGION WITH CONCERNS OF
FLASH FLOODING. SUNDAY AND MONDAY STILL LOOK PRETTY WET FOR THE
MOUNTAINS...BUT THE PLAINS LOOK MORE STABLE WITH LESS ACTIVITY. ALL
OF THIS IS STILL SEVERAL DAYS AWAY AND HIGHLY SUBJECT TO
CHANGE...HOWEVER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 240 PM MDT MON SEP 1 2014
VFR CONDITIONS ARE ANTICIPATED AT THE KALS...KCOS AND KPUB TAF SITES
THROUGH TUESDAY AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...77
LONG TERM...LW
AVIATION...LW
AREA FORECAST DISCUSSION
NWS TAUNTON MA
716 PM EDT TUE SEP 2 2014
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TONIGHT AND WILL BE ACCOMPANIED
BY SCATTERED SHOWERS AND THUNDERSTORMS. BEHIND THE FRONT DRIER AND
MUCH LESS HUMID AIR OVERSPREADS THE AREA WEDNESDAY AND THURSDAY.
HUMIDITY WILL ONCE AGAIN INCREASE BY THE END OF THE WEEK AS THE NEXT
COLD FRONT BRINGS THE RISK FOR MORE SCATTERED SHOWERS/THUNDERSTORMS
FRIDAY NIGHT AND SATURDAY. MORE AUTUMN-LIKE WEATHER FOLLOWS SUNDAY
AND INTO AT LEAST EARLY NEXT WEEK WITH COOLER AND LESS HUMID
CONDITIONS.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
7 PM UPDATE...
NOT MUCH CHANGE TO PREVIOUS FORECAST. LATEST MESOSCALE MODELS
INCLUDING THE RAP13 AND HRRR SUGGEST UPSTREAM CONVECTION OVER
WESTERN-CENTRAL NY INTO PA WILL ENTER WESTERN NEW ENGLAND BETWEEN
9 PM AND 11 PM. A FEW STRONG STORMS ARE POSSIBLE ACROSS THIS AREA
WITH GUSTY WINDS/HAIL AND HEAVY DOWNPOURS. THE LINE OF STORMS IS
THEN EXPECTED TO WEAKEN LATER THIS EVENING AND OVERNIGHT AS THE
ACTIVITY MOVES EAST OF THE CT RVR. PREVIOUS FORECAST CAPTURES
THESE DETAILS NICELY SO NO MAJOR CHANGES WITH THIS UPDATE. EARLIER
DISCUSSION BELOW.
==================================================================
TONIGHT...
STRONG COLD FRONT WILL MOVE ACROSS THE NORTHEAST OVERNIGHT. THIS
FRONT IS EXPECTED TO MOVE INTO THE WESTERN ZONES AROUND 02-04Z AND
OFFSHORE BETWEEN 10-12Z. ANTICIPATE CONVECTION WILL BE ONGOING AS IT
APPROACHES THE REGION PER THE AMOUNT OF SURFACE HEATING AND DYNAMICS
OUT AHEAD OF IT IN WESTERN CWA`S. BY THE TIME IT APPROACHES THE
REGION A GOOD AMOUNT OF INSTABILITY WILL BE LOSS SO WE MAY SEE DYING
CONVECTION. HOWEVER SOME MODELS...ESP THE HIGH-RES GUIDANCE SHOWS
ABOUT 500 J/KG OF CAPE LINGERING BY THE TIME THE FRONT APPROACHES.
ON TOP OF THE POSSIBLE INSTABILITY...850MB LLJ DOES INCREASE AS THE
FRONT APPROACHES AND SHEAR VALUES INCREASE AS WELL. IN
FACT...GUIDANCE SHOWS THAT 0-6KM SHEAR INCREASES TO 25KTS...BUT IT
IS THE 0-1 KM SHEAR THAT INCREASES TO 30-40KTS. LASTLY K-INDEX PLUME
MOVES OVER THE REGION DURING THIS TIMEFRAME GIVING THE REGION THE
MOISTURE IT NEEDS FOR THUNDERSTORMS TO CONTINUE.
THEREFORE BELIEVE THAT ALL THE INGREDIENT MENTIONED ABOVE MAY ALLOW
FOR A FEW STRONG TO PERHAPS A SEVERE STORM AS THE FRONT MOVES THE
REGION. KEEP IN MIND THAT THIS IS AN OVERNIGHT EVENT WHICH IS NOT IN
THE NORTHEAST FAVOR PER CLIMO...BUT CONDITIONS DO SHOW THAT A FEW
STRONG STORMS ARE POSSIBLE. LASTLY...EVEN THOUGH THE REGION DID SEE
SOME ACTION TODAY...THE ATMOSPHERE DID BOUNCE BACK VERY WELL AFTER
THE STORMS PASSED.
AS THE FRONT MOVES THROUGH THE K-INDEX VALUE AS WELL AS THE
INSTABILITY DO DROP AFTER 06Z SO THAT THE CHANCE FOR ANY CONVECTION
TO OCCUR DISSIPATES SIGNIFICANTLY. IN FACT...THE SHOWERS AND
THUNDERSTORMS FROM THE FRONT WILL FRAGMENT AND BECOME VERY ISO IN
NATURE BY THIS TIME FRAME AND MAY EVEN STRUGGLE TO REACH THE EAST
COAST. WITH THE AMOUNT OF MOISTURE IN THE ATMOSPHERE BELIEVE THAT A
FEW SHOWERS WILL REACH SO CONTINUED THE SLIGHT CHANCE POP FOR NOW.
OVERNIGHT TEMPS WILL STRUGGLE TO DROP AS CLOUD COVER WILL KEEP TEMPS
FROM RADIATING OUT OVERNIGHT AND DEWPOINTS WILL REMAIN IN THE 70S
UNTIL FRONTAL PASSAGE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
TOMORROW AND TOMORROW NIGHT...
SURFACE FRONT WILL MOVE OFFSHORE BY EARLY TOMORROW MORNING AS UPPER
LEVEL TROUGH WILL PUSH THROUGH AS WELL. 850 MB RIDGE WILL BEGIN TO
SET UP OVER THE REGION ALLOWING FOR DRY AIR TO MOVE INTO THE AREA.
THIS WILL KEEP THE WEATHER DRY FOR BOTH TOMORROW AND TOMORROW NIGHT.
850 MB TEMPS DROP DOWN TO -14C AND WITH MIXING UP TO 850MB WILL ALLOW
FOR TEMPS TO REACH INTO THE MID TO UPPER 80S. DIFFERENCE WILL BE THE
HUMIDITY AS DRY AIR WILL MIX DOWN DROPPING DEWS DOWN INTO THE UPPER
50S. WINDS WILL BE GUSTY REACHING ABOUT 20 MPH.
OVERNIGHT...WITH CLEAR SKIES AND WINDS BECOME LIGHT AND
VARIABLE...ANTICIPATE RADIATIONAL COOLING. LOWS WILL DROP INTO THE
MID TO LOW 50S. A FEW SITES COULD EVEN DROP INTO THE UPPER 40S
ACROSS CT VALLEY.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS:
* DRY THU/FRI WITH WARMER THAN NORMAL AFTERNOON TEMPS
* MORE HUMID SAT WITH SCATTERED STORMS POSSIBLE
* TREND TOWARD COOLER/LESS HUMID WEATHER SUN INTO EARLY NEXT WEEK
THURSDAY AND FRIDAY...
DRY/QUIET WEATHER CONTINUES THU WITH HIGH PRES AND A DRY/STABLE
AIRMASS OVER THE REGION. IT WILL BE WARM WITH HIGHS OF 80-
85...COOLER ALONG THE COAST WITH AFTERNOON SEABREEZES...HOWEVER DEW
PTS REMAINING IN THE 50S WILL PROVIDE COMFORTABLE HUMIDITY LEVELS.
BY FRIDAY THE SUBTROPICAL RIDGE ALONG THE EAST COAST BRIEFLY BUILDS
NORTHWARD INTO SOUTHERN NEW ENGLAND AHEAD OF THE NEXT NORTHERN
STREAM TROUGH. THIS WILL RESULT IN WARMER TEMPS WITH HIGHS WELL INTO
THE 80S COMBINED WITH MORE HUMID CONDITIONS AS DEW PTS CLIMB FROM
THE 50S INTO THE 60S. THUS A WARM AND HUMID DAY FRIDAY.
ALL MODEL GUIDANCE INCLUDING THE 12Z GEFS AND NEW 12Z ECMWF SUGGEST
JET DYNAMICS/BEST SHEAR/INSTABILITY AND CONVERGENCE ASSOCIATED WITH
COLD FRONT HOLD OFF UNTIL SAT. THUS SLIGHT CHANCE POPS CONFINED TO
WESTERN NEW ENGLAND LATE FRI FROM A MODEL BLEND SEEMS REASONABLE.
HENCE MOST OF THE AREA ESPECIALLY RI AND EASTERN MA MAY REMAIN DRY
FRI.
SATURDAY...
ALL DETERMINISTIC AND PROBABILISTIC /12Z GEFS AND 12Z ECENS/ GUIDANCE
SUGGEST COLD FRONT WILL MOVE SLOWLY INTO THE REGION SAT. TEMPS ARE
PROJECTED TO BE IN THE 80S SAT ALONG WITH DEW PTS IN THE 60S TO NEAR
70 SO THIS SHOULD YIELD AT LEAST MARGINAL INSTABILITY. THE 12Z GEFS
SUGGEST A 30-40% PROBABILITY OF UP TO 1200 J/KG OF CAPE. THIS
COMBINED WITH MODEST JET DYNAMICS/SHEAR AND FRONTAL CONVERGENCE
EXPECTING A RISK FOR SCATTERED THUNDERSTORMS ALONG WITH A THREAT FOR
HEAVY RAIN AS PWATS CLIMB ABOVE NORMAL. COULD BE A FEW STRONG STORMS
GIVEN THE PARAMETERS MENTIONED ABOVE.
SUNDAY...
LIKELY OUR TRANSITION DAY AS BOTH ENSEMBLES /12Z ECENS AND GEFS/
SUGGEST FRONT MAY BE SLOW TO CLEAR THE COAST SUN MORNING. THUS
SHOWERS MAY LINGER EARLY SUNDAY ESPECIALLY SOUTH COAST WITH A TREND
TOWARD DRIER WEATHER AS THE DAY PROGRESSES FROM NW TO SE.
MONDAY AND TUESDAY...
SHOULD BE DRIER...COOLER AND LESS HUMID AS FRONT MOVES OFFSHORE.
HOWEVER SOME OF THE GUIDANCE SHOWS UNCERTAINTY HOW FAR OFFSHORE THIS
BOUNDARY GETS. THUS CLOUDS AND POSSIBLE UNSETTLED WEATHER MAY LURK
JUST OFFSHORE. WILL KEEP THE FORECAST DRY FOR NOW.
&&
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH WEDNESDAY NIGHT/...HIGH CONFIDENCE IN
TRENDS.
7 PM UPDATE...NO MAJOR CHANGES FROM 18Z TAFS. SHOWERS AND T-STORMS
OVER MA CONTINUE TO ERODE. NEXT ROUND OF T-STORMS OVER WESTERN-
CENTRAL NY AND PA ARRIVES IN WESTERN NEW ENGLAND 01Z-03Z THEN
WEAKENS AS IT ENTERS EASTERN NEW ENGLAND. FOG AT NANTUCKET WILL
PERSIST AND THEN BEGIN TO IMPROVE AROUND 06Z AND ESPECIALLY 09Z-
12Z WHEN FRONTAL PASSAGE OCCURS. EARLIER DISCUSSION BELOW.
==============================================================
TONIGHT...A LULL IN ACTIVITY AFTER 00Z. BEFORE ANOTHER ROUND OF
SHOWERS WITH ISO THUNDER MOVES THROUGH AFTER 03/04Z. THIS
CONVECTION IS ASSOCIATED WITH AN APPROACHING COLD FRONT WHICH
WILL PASS THROUGH THE REGION OVERNIGHT. EXPECT CONVECTION TO
WEAKEN AS IT MOVES THROUGH WITH BRIEF LOWERING IN CIG HEIGHTS.
PATCHY FOG IS EXPECT AHEAD OF THE FRONT AND SHOULD DISSIPATE AS
IT PASSES THROUGH.
WED INTO WED NIGHT...VFR. PATCHY FOG IN CT VALLEY WED NIGHT.
KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS. MAY BE A SHOWER OR
THUNDERSHOWER IN THE AFTERNOON.
KBDL TERMINAL...HIGH CONFIDENCE.
OUTLOOK...THURSDAY THROUGH SATURDAY...
THU AND FRIDAY...HIGH CONFIDENCE. MAINLY VFR CONDITIONS OTHER THAN
LATE NIGHT/EARLY MORNING PATCHY GROUND FOG IN THE TYPICALLY PRONE
LOCATIONS.
FRIDAY NIGHT AND SATURDAY...MODERATE CONFIDENCE. A PERIOD OF MVFR-
IFR CONDITIONS EXPECTED IN LOW CLOUDS/FOG PATCHES AND SCT
SHOWERS/THUNDERSTORMS. TIMING HIGHLY UNCERTAIN AT THIS POINT.
SUNDAY...ANY MVFR ALONG SOUTH COAST SHOULD TREND TOWARD VFR WITH
POTENTIAL SHOWERS MOVING OFFSHORE. OTHERWISE VFR PREVAILS
ELSEWHERE.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH THE PERIOD WEDNESDAY NIGHT.
TONIGHT...
SW FLOW BEGINS TONIGHT BEFORE A COLD FRONT PASSES OVER THE WATERS
OVERNIGHT. EXPECT A FEW GUSTS TO AROUND 20 KT ARE POSSIBLE AS THE
WINDS SHIFT TO THE W-NW. A FEW SHOWERS AND THUNDERSTORMS MAY MOVE
OVER THE SOUTHERN WATERS BY MIDNIGHT LASTING TIL ABOUT 3AM. SEAS
MAY APPROACH 5 FT ON THE SOUTH OCEAN WATERS BUT HAVE LOW
CONFIDENCE AND HELD OFF ON ISSUING A SCA. OTHERWISE...SOME FOG MAY
LEAD TO VSBY REDUCTIONS TONIGHT BEFORE THE FRONT PASSES.
WED INTO WED NIGHT...QUIET BOATING WEATHER. A FEW GUSTS NEAR 15KTS
POSSIBLE DURING THE DAY.
OUTLOOK...THURSDAY THROUGH SATURDAY...
MODERATE CONFIDENCE THROUGH THIS PERIOD.
THURSDAY...HIGH CONFIDENCE. WEAK PRESSURE GRADIENT YIELDS LIGHT
WINDS AND SEAS ALONG WITH GOOD VISIBILITIES SHOULD MAKE FOR NICE
BOATING WEATHER. AFTERNOON SEABREEZES EXPECTED.
FRIDAY...MODERATE TO HIGH CONFIDENCE. NEAR SHORE SOUTHWEST WIND
GUSTS OF 20 TO 25 KNOTS MAY DEVELOP IN THE AFTERNOON WITH GOOD
MIXING OVER THE LAND. SW WIND WAVES DEVELOP ESPECIALLY NEAR SHORE.
DRY WEATHER WILL PREVAIL WITH A CHANCE OF SHOWERS/T-STORMS
INCREASING AFTER SUNSET.
FRIDAY NIGHT AND SATURDAY...MODERATE CONFIDENCE. AREAS OF FOG MAY
AFFECT THE SOUTHERN WATERS. SOUTHWEST WIND GUSTS AROUND 20 KNOTS
ARE EXPECTED AHEAD OF AN APPROACHING COLD FRONT. THERE WILL BE THE
RISK OF SCT SHOWERS AND THUNDERSTORMS DURING THE DAY SATURDAY WITH A
FEW STRONG STORMS POSSIBLE...WIND AND HEAVY RAIN.
SUNDAY...FRONT BEGINS TO MOVE OFFSHORE SLOWLY BUT SHOWERS MAY LINGER
ESPECIALLY IN THE MORNING.
&&
.CLIMATE...
BOSTON LOGAN AIRPORT REACHED 93 DEGREES TODAY. THIS IS THE WARMEST
TEMPERATURE IN BOSTON SO FAR THIS SUMMER.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NOCERA/DUNTEN
NEAR TERM...NOCERA/DUNTEN
SHORT TERM...DUNTEN
LONG TERM...NOCERA
AVIATION...NOCERA/DUNTEN
MARINE...NOCERA/DUNTEN
CLIMATE...
AREA FORECAST DISCUSSION
NWS ALBANY NY
1034 AM EDT MON SEP 1 2014
.SYNOPSIS...
HIGH PRESSURE WILL BRING A RETURN TO SOME SUNSHINE AND
VERY WARM TEMPERATURES TODAY. IT WILL REMAIN HUMID...AS
TEMPERATURES COULD TURN EVEN HOTTER ON TUESDAY. A COLD FRONT WILL
APPROACH THE REGION LATE TUESDAY INTO TUESDAY EVENING BRINGING
NUMEROUS SHOWERS AND THUNDERSTORMS...AND SLIGHTLY COOLER AND
NOTICEABLY DRIER AIR WILL FOLLOW ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1034 AM EDT...A WEAK SFC RIDGE WILL BUILD IN OVER NY AND NEW
ENGLAND TODAY...AS THE WATER VAPOR LOOP SHOWS SOME DRYING ALOFT
WITH THE PASSAGE OF A MID-LEVEL SHORT WAVE OVER NRN NEW ENGLAND.
MID LEVEL HEIGHTS ARE BUILDING UPSTREAM OVER SE CANADA...W-CNTRL NY
AND PA THIS MORNING.
THE LATEST 3-KM HRRR SHOWS VERY LITTLE CONVECTIVE ACTIVITY THIS PM
WITH A MID LEVEL CAP SETTING UP...AND A LACK OF A GOOD FOCUSING
MECHANISM. THE BEST CHC FOR AN ISOLD-SCT POP UP SHOWER OR
THUNDERSTORM IS SOUTH OF THE CAPITAL REGION. SBCAPE VALUES WILL BE
IN THE 1000-1500 J/KG RANGE THERE...AND THE DIFFERENTIAL HEATING
BTWN THE MTNS/VALLEYS COULD ALLOW FOR SOME POP-UP ACTIVITY. ISOLD-
SCT SHOWERS WITH AN ISOLD THUNDERSTORM WERE ONLY KEPT IN THE FCST
SOUTH OF THE CAPITAL REGION FOR MAINLY THE MID TO LATE PM.
HIGHS TODAY WILL GENERALLY BE IN THE LOWER TO M80S...WITH A FEW
U80S IN THE MID HUDSON VALLEY/NW CT. EXPECT U70S TO L80S OVER THE
MTNS. IT WILL REMAIN VERY HUMIDITY WITH SFC DEWPTS IN THE M60S TO
L70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
ANY LEFTOVER CONVECTION WILL END SHORTLY AFTER SUNSET...LEAVING US
WITH A RAINFREE BUT MUGGY OVERNIGHT. MORE PATCHES OR EVEN AREAS OF
FOG WILL FORM AFTER MIDNIGHT. LOWS WILL BE IN THE 60S...CLOSE TO 70
IN THE TRI-CITY REGION.
TUESDAY...A SOUTH TO SOUTHWEST WIND WILL INCREASE A LITTLE AHEAD OF
COLD FRONT APPROACHING FROM THE NORTHWEST. H850 TEMPERATURES LOOK TO
RAMP UP TO ABOUT +18C. WITH ANY MORNING AND MIDDAY
SUNSHINE...TEMPERATURES LOOK TO GO EVEN A LITTLE HIGHER THAN
TODAY...80S...TO NEAR 90 JUST SOUTH OF THE CAPITAL REGION. THE ONLY
EXCEPTION WILL BE THE ADIRONDACK PARK WHERE MORE CLOUDS AND
SHOWERS/THUNDERSTORMS...ASSOCIATED WITH AN ADVANCING COLD
FRONT...WILL KEEP TEMPERATURES HELD TO THE UPPER 70S.
APPARENT TEMPERATURES ON TUESDAY AFTERNOON ARE FORECASTED TO REACH
THE UPPER 90S IN PORTIONS OF THE MID HUDSON VALLEY...GENERALLY LOWER
TO MID MOST OTHER VALLEY AREAS...80S OVER THE HIGHER TERRAIN.
THE AFOREMENTIONED COLD FRONT (AND PERHAPS A PRE-FRONTAL TROUGH)
WILL ADVANCE OVER MOST OUR REGION DURING THE AFTERNOON AND EARLY
EVENING HOURS. THIS FRONT PRODUCED QUITE OF BIT OF THUNDERSTORM WIND
DAMAGE AND SOME LARGE HAIL IN THE MID WEST.
SHOWERS AND THUNDERSTORMS WILL LIKELY DEVELOP ALONG OR A LITTLE
AHEAD OF THESE FEATURES. IT DOES APPEAR THE BEST FORCING WILL
ACTUALLY LIFT INTO CANADA AS THE RIGHT ENTRANCE REGION OF THE UPPER
LEVEL JET MOVES THAT WAY.
NEVERTHELESS THERE SHOULD BE PLENTY OF INSTABILITY...LOW LEVEL
CONVERGENCE (ASSOCIATED WITH THE FRONT)...AND MOISTURE...TO GENERATE
SHOWERS AND STORMS. AN ORGANIZED LINE COULD EVEN FORM. FOR
NOW...SINCE WE ARE NOT OFFICIALLY OUTLOOKED BY SPC...WE WILL ONLY
MENTION POSSIBLE HEAVY RAINFALL WITH THE THUNDERSTORMS ON TUESDAY
SINCE PWAT VALUES WILL ONCE AGAIN INCREASE TO 2 INCHES OR
BETTER...EXCEEDING 70% OF NORMAL AMOUNTS FOR EARLY SEPTEMBER.
SHOWERS AND THUNDERSTORMS COULD LINGER INTO TUESDAY EVENING...BUT AT
THIS POINT...THE FRONT LOOKS TO MOVE FAIRLY QUICKLY EAST AND BE
REPLACED BY SOMEWHAT DRIER AND COOLER AIR. THE THUNDERSTORM THREAT
LOOKS TO WANE BY MIDNIGHT. TEMPERATURES OVERNIGHT TUESDAY LOOK TO
FALL BACK INTO THE MID 50S TO THE NORTHWEST OF ALBANY...60-65
FURTHER SOUTH.
AN AIRMASS ORIGINATING FROM SOUTHERN CANADA WILL BRING A GUSTY
NORTHWEST BREEZE WHICH WILL DROP DEWPOINTS BACK INTO THE 50S ON
WEDNESDAY. HIGH TEMPERATURES WILL ACTUALLY STILL BE SLIGHTLY ABOVE
NORMAL...RANGING FROM THE MID 70S TO MID 80S...LOCALLY AROUND 80 IN
ALBANY. HOWEVER...WITH THE BREEZE AND LOWER HUMIDITY...IT WILL BE
MORE PLEASANT OUTDOORS.
A MAINLY CLEAR NIGHT ON WEDNESDAY AND LIGHT WIND WILL ALLOW
TEMPERATURES SETTLE BACK INTO THE 50S ACROSS MUCH OF OUR
AREA...EXCEPT MID OR UPPER 40S OVER PORTIONS OF THE ADIRONDACKS AND
SOUTHERN GREENS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE LONG TERM PERIOD STARTS OUT WITH HIGH PRESSURE IN CONTROL AND
INCREASINGLY WARM TEMPS AS A SOUTHWESTERLY FLOW TAKES HOLD ON THE
WESTERN SIDE OF A LARGE HIGH PRESSURE THAT WILL BE SLIDING OFF THE
COAST. MAINLY DRY WEATHER IS FORECAST WITH ONLY A SLIGHT CHANCE OF
SHOWERS/TSTMS LATER FRIDAY AFTN AS A COLD APPROACHES FROM THE GREAT
LAKES. HIGHS THURSDAY WILL BE IN THE UPPER 70S TO MID 80S...AND A
COUPLE OF DEGREES WARMER ON FRIDAY. LOWS THURSDAY NIGHT IN THE MID
50S TO LOWER 60S.
THE COLD FRONT WILL MOVE INTO THE REGION AT THE START OF THE WEEKEND
ALONG WITH THE THREAT OF SHOWERS/TSTMS. SOME MODEL DISAGREEMENT AS
TO HOW FAST THIS FRONT WILL MOVE THROUGH. THE CANADIAN MODEL IS THE
FASTEST OF ALL AND ACTUALLY HAS THE FRONT SOUTH AND EAST OF THE
REGION BY SATURDAY MORNING WITH PCPN ENDING. ECMWF LINGERS THE FRONT
OVER THE REGION THROUGH THE WEEKEND WITH A CHANCE OF SHOWERS/TSTMS
THROUGH MUCH OF SUNDAY. THE GFS IS IN BETWEEN WITH THE FRONT SOUTH
AND EAST OF THE REGION BY SATURDAY AFTERNOON WITH THE THREAT OF
SHOWERS CONFINED TO FRIDAY NIGHT AND EARLY SATURDAY. CANADIAN SEEMS
TOO FAST...SO TAKEN A COMPROMISE BETWEEN THE GFS AND ECMWF WITH A
CHANCE OF SHOWERS FORECAST FRIDAY NIGHT THROUGH SATURDAY
NIGHT...THEN CLEARING AND COOLER ON SUNDAY AS A LARGE CANADIAN HIGH
PRESSURE SYSTEM BUILDS INTO THE REGION. LOWS FRIDAY NIGHT WILL BE IN
THE UPPER 50S TO MID 60S. HIGHS SATURDAY IN THE 70S TO LOWER 80S.
LOWS SATURDAY NIGHT IN THE UPPER 40S AND 50S. HIGHS SUNDAY IN THE
MID 60S TO MID 70S.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
MVFR TO OCCASIONAL IFR CONDITIONS DUE TO FOG/STRATUS WILL PERSIST AT
THE KGFL/KALB/KPSF TAF SITES TO 12Z-14Z THIS MORNING...WITH VFR TO
OCCASIONALLY MVFR VSBYS AT KPOU THROUGH 14Z. AFTER AROUND
13Z...VFR CONDITIONS WILL RETURN TO ALL THE TAF SITES. LINGERING
LOW LEVEL MOISTURE AND SOME WEAK INSTABILITY COULD RESULT IN
ISOLATED SHOWERS/TSTMS THIS AFTN...SO HAVE INCLUDED VCSH IN THE
TAF FORECASTS FROM AROUND 19Z THRU 00Z TUESDAY. FOR
TONIGHT...EXPECT MAINLY CLEAR SKIES AND LIGHT WINDS...SO FOG
FORMATION IS LIKELY AGAIN. HAVE FORECAST CONDITIONS TO LOWER TO
MVFR/IFR AT ALL THE TAF SITES AROUND AND AFTER MIDNIGHT.
WINDS WILL BE CALM OR LIGHT AND VARIABLE EARLY THIS MORNING...THEN
BECOME SOUTH OR SOUTHWEST AT 8 KTS OR LESS DURING THE REST OF THE
DAY. THE WINDS WILL BECOME LIGHT AND VARIABLE OR CALM AGAIN TONIGHT.
OUTLOOK...
TUESDAY: HIGH OPERATIONAL IMPACT. LIKELY PM SHRA...TSRA.
TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHC SHRA...TSRA.
WEDNESDAY THROUGH FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
TODAY WILL FEATURE PATCHES OF FOG TO START THE DAY. A STRAY SHOWER
OR THUNDERSTORM IS POSSIBLE THIS AFTERNOON...MAINLY SOUTH OF
ALBANY...BUT THAT WILL BE EXCEPTION RATHER THAN THE RULE.
WITH ONLY A LIGHT WIND...MAINLY OUT OF THE SOUTHWEST...RH VALUES
WILL REMAIN ELEVATED TODAY...ONLY DROPPING TO THE 55-65 PERCENT
RANGE. IT WILL BE VERY WARM WITH A GOOD DEAL OF SUNSHINE (ONCE THE
FOG BURNS OFF).
LOOK FOR A FULL RECOVERY TONIGHT WITH MORE FOG AND RH VALUES NEAR
100 PERCENT.
TUESDAY WILL BE VERY WARM ONCE MORE. SOME SUNSHINE SHOULD BURN THE
FOG AWAY PERHAPS A LITTLE QUICKER THAN TODAY. BY AFTERNOON
THOUGH...A COLD FRONT WILL APPROACH...LIKELY TRIGGERING ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS...SOME OF WHICH COULD CONTAIN
TORRENTIAL RAINFALL.
DRIER AND SLIGHTLY COOLER AIR WILL FILTER IN BEHIND THE COLD FRONT
LATE TUESDAY NIGHT AND HOLD FOR THE REMAINDER OF THE WEEK.
&&
.HYDROLOGY...
THERE WERE POCKETS OF ONE INCH OR MORE OF RAINFALL...MAINLY NORTH
AND SOUTH OF THE CAPITAL REGION ON SUNDAY. MOST AREAS HOWEVER
RECEIVED WELL UNDER AN INCH OF RAINFALL. THERE WAS LITTLE IF ANY
IMPACT ON MAIN STEM RIVERS SINCE WE HAD BEEN DRY BEFORE THIS RAIN
MOVED IN.
ANY SHOWERS OR THUNDERSTORMS TODAY WILL BE WIDELY SCATTERED AND
SHOULD HAVE NO IMPACT ON OUR WATERSHED.
TUESDAY COULD BE A DIFFERENT STORY. WE EXPECT NUMEROUS SHOWERS AND
THUNDERSTORMS AFTERNOON AND EVENING. AVERAGE BASIN RAINFALL LOOKS TO
BE MAINLY UNDER AN INCH SO ONCE AGAIN WE DO NOT EXPECT MANY IF ANY
RISES ON THE RIVERS. HOWEVER...RAINFALL COULD BE LOCALLY HEAVY
PRODUCING THE USUAL PONDING PROBLEMS.
DRIER WEATHER RETURNS BY WEDNESDAY...LASTING THROUGH THE REMAINDER
OF THE WORKWEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...HWJIV/WASULA
NEAR TERM...WASULA
SHORT TERM...HWJIV
LONG TERM...GJM
AVIATION...GJM/WASULA
FIRE WEATHER...HWJIV
HYDROLOGY...HWJIV
AREA FORECAST DISCUSSION
NWS MIAMI FL
130 PM EDT MON SEP 1 2014
.AVIATION...
MOSTLY VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST. SEA
BREEZE CIRCULATION APPEARS TO HAVE FINALLY SET UP ALONG THE EAST
COAST WITH MOST SHRA ACTIVITY DIMINISHING. STILL COULD HAVE ONE OR
TWO SHRA DEVELOP UNTIL AROUND 20Z BUT TOO ISOLATED TO PLACE
MENTION IN THE TAF AT THIS TIME. LATEST SHORT TERM HIGH RESOLUTION
GUIDANCE INDICATES CONVECTION WILL BEGIN TO FIRE ALONG THE
SOUTHWEST COAST BTWN 18-19Z SO KEPT MENTION OF VCTS IN THE KAPF
TAF. GUIDANCE ALSO INSISTING EAST FLOW TOO STRONG AND WILL INHIBIT
THE WEST COAST SEA BREEZE FROM SETTING UP BUT THE WIND AT KAPF MAY
BECOME MORE SSE AS THE CIRCULATION TRIES TO DEVELOP.
KOB
&&
.PREV DISCUSSION... /ISSUED 1021 AM EDT MON SEP 1 2014/
UPDATE...
THE LATEST WATER VAPOR IMAGERY INDICATES THE MID TO UPPER LEVEL
TROUGH CONTINUES TO RETROGRADE TO THE SOUTHWEST AND IS ENTERING
THE NORTHWEST BAHAMAS. THIS IS BRINGING IN SOME DRIER MID TO UPPER
LEVEL AIR INTO SOUTH FLORIDA AND ADJACENT WATERS THIS MORNING.
RECENT RADAR RETURNS INDICATE ISOLATED SHOWER ACTIVITY MAINLY
ACROSS THE ATLANTIC WATERS. MINOR UPDATES WERE DONE TO THE SHORT
TERM FORECAST TO REFLECT THE CURRENT CONDITIONS. BUT AS THE
AFOREMENTIONED TROUGH CONTINUES TO MOVE TO THE SOUTHWEST AND INTO
THE REGIONAL ATLANTIC WATERS...THAT WILL LIKELY ALLOW FOR SOME
POTENTIAL FOR CONVECTION. THERE IS CURRENTLY ACTIVE CONVECTION IN
THE NORTHWEST BAHAMAS ISLANDS. SO THE FORECAST REFLECTS SCATTERED
SHOWER/THUNDERSTORM ACTIVITY POSSIBLE OVER THE ATLANTIC WATERS
AND EAST COAST METRO AREAS LATER THIS AFTERNOON WITH GREATER
COVERAGE EXPECTED ACROSS THE WESTERN PENINSULA LATE THIS AFTERNOON
WHERE THE SURFACE CONVERGENCE WILL BE MOST DOMINANT. SO OVERALL NO
SIGNIFICANT CHANGES FROM PREVIOUS FORECAST OR SYNOPTIC REASONING
EXCEPT FOR THE VERY SHORT TERM.
60
PREV DISCUSSION... /ISSUED 728 AM EDT MON SEP 1 2014/
AVIATION...
MOSTLY VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST WITH A
MODERATE EAST WIND FLOW. ANTICIPATED TSRA DEVELOPMENT WILL BE OVER
THE INTERIOR WITH A WESTWARD PROPAGATION. AT THIS TIME, PLACED A
VCTS IN THE KAPF TAF AFT 19Z AND THEY COULD HAVE A BRIEF MVFR OR
EVEN IFR CIG/VSBY THROUGH THE AFTERNOON. EAST FLOW WILL PREVENT A
SEA BREEZE ALONG THE SOUTHWEST COAST BUT WIND IS LIKELY TO VEER TO
THE SSE AS IT TRIES TO FORM.
KOB
PREV DISCUSSION... /ISSUED 329 AM EDT MON SEP 1 2014/
HIGHLIGHTS...
* MODERATE RISK OF RIP CURRENTS ATLANTIC BEACHES
* SLIGHT TSTORM CHANCE EAST COAST, BETTER CHANCE GULF COAST TODAY
* STORMIER PATTERN MID-LATE WEEK; STRONG STORMS POSSIBLE
DISCUSSION...
THE WEATHER PATTERN ON THIS LABOR DAY WILL REMAIN
MOSTLY UNCHANGED FROM YESTERDAY. RIDGE AXIS WILL REMAIN OVER NORTH
FLORIDA, MAINTAINING AN EASTERLY WIND FLOW LOCALLY WITH CONVECTIVE
FOCUS ALONG THE GULF COAST IN THE AFTERNOON. LOW LEVEL WINDS WILL
BE STRONG ENOUGH TO DISALLOW A FULL GULF SEA BREEZE FROM
DEVELOPING, BUT SOME VEERING OF THE WIND FIELD IS EXPECTEDTHERE
WHICH AGAIN WILL LEAD TO ENOUGH CONVERGENCE TO SPARK SOME TSTORM
DEVELOPMENT. ACROSS THE EAST COAST, HRRR SHOWS A SCENARIO SIMILAR
TO YESTERDAY WITH QUICK PASSING SHOWERS DEVELOPING. CANNOT RULE
OUT TSTORMS EAST COAST BUT CONVERGENCE WILL BE LACKING SO COVERAGE
WOULD BE ISOLATED AT BEST.
LIKE YESTERDAY, A LIMITING FACTOR FOR MORE ACTIVE TSTORMS IS THE
LACK OF A FULL FLEDGED ONSHORE GULF SEA BREEZE. HOWEVER, CANNOT
RULE OUT A STRONG TSTORM OR TWO GIVEN SOME CONVERGENCE ALONG WITH
THE INSTABILITY AND CONTINUED DRY AIR ALOFT. WIND GUSTS OF 40-50
MPH IS THE PRIMARY THREAT.
A DEEP LAYERED TROUGH EAST OF THE BAHAMAS IS SHOWN BY THE GLOBAL
MODELS TO MOVE WEST AND ACROSS SOUTH FLORIDA WED NIGHT-THU. THIS
WILL BE ASSOCIATED WITH COOLING ALOFT ALONG WITH INCREASING
MOISTURE, SPELLING A STORMIER PERIOD MID WEEK AND EVEN INTO LATE
WEEK AS HIGHER INSTABILITY REMAINS. POPS ACCORDINGLY SHOW AN
UPWARD TREND MID-LATE WEEK. COULD SEE SOME STRONG STORMS ANYWHERE
BEGINNING WED THROUGH LATE WEEK DUE TO THE COLD AIR ALOFT AND
TROUGH PASSAGE, THOUGH MORE CLOUDINESS WOULD BE A LIMITING FACTOR.
/GREGORIA
AVIATION...
HIGH PRESSURE WILL SLOWLY WEAKEN OVER THE SOUTHEASTERN UNITED
STATES TODAY WHICH IN TURN WILL KEEP A EASTERLY WIND FLOW OF
AROUND 5 KNOTS THROUGH EARLY THIS MORNING AT ALL OF THE TAF SITES.
THE WIND DIRECTION WILL REMAIN EASTERLY AFTER 14Z TODAY BUT
INCREASE TO AROUND 10 KNOTS OVER ALL OF THE TAF SITES.
THE WEATHER SHOULD REMAIN DRY THROUGH THE EARLY MORNING HOURS BEFORE
SOME SHOWERS WORKS INTO THE EAST COAST TAF SITES AFTER 14Z.
SO WILL PUT IN VCSH AFTER 14Z FOR THE EAST COAST TAF SITES. FOR
KAPF TAF SITE...THE WEATHER WILL ALSO REMAIN DRY THROUGH MOST OF
THIS LABOR DAY. HOWEVER...A LATE WEST COAST SEA BREEZE COULD
DEVELOP AND PUSH INTO THE KAPF TAF SITE AFTER 21Z TODAY. SO WILL
PUT IN VCTS BETWEEN 21Z AND 00Z TODAY.
THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS AT ALL
OF THE TAF SITES FOR THIS LABOR DAY.
MARINE...EAST SOUTHEAST WINDS LESS THAN 15 KT WILL PREVAIL AS
THE ATLANTIC RIDGE REMAINS NORTH OF THE LOCAL WATERS. SEAS WILL BE
CORRESPONDINGLY LOW. A TROUGH WILL MOVE ACROSS THE WATERS LATE
WED- THU, BRINGING AN INCREASING CHANCE OF THUNDERSTORMS
ESPECIALLY ACROSS THE ATLANTIC WATERS.
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
1021 AM EDT MON SEP 1 2014
.UPDATE...
THE LATEST WATER VAPOR IMAGERY INDICATES THE MID TO UPPER LEVEL
TROUGH CONTINUES TO RETROGRADE TO THE SOUTHWEST AND IS ENTERING
THE NORTHWEST BAHAMAS. THIS IS BRINGING IN SOME DRIER MID TO UPPER
LEVEL AIR INTO SOUTH FLORIDA AND ADJACENT WATERS THIS MORNING.
RECENT RADAR RETURNS INDICATE ISOLATED SHOWER ACTIVITY MAINLY
ACROSS THE ATLANTIC WATERS. MINOR UPDATES WERE DONE TO THE SHORT
TERM FORECAST TO REFLECT THE CURRENT CONDITIONS. BUT AS THE
AFOREMENTIONED TROUGH CONTINUES TO MOVE TO THE SOUTHWEST AND INTO
THE REGIONAL ATLANTIC WATERS...THAT WILL LIKELY ALLOW FOR SOME
POTENTIAL FOR CONVECTION. THERE IS CURRENTLY ACTIVE CONVECTION IN
THE NORTHWEST BAHAMAS ISLANDS. SO THE FORECAST REFLECTS SCATTERED
SHOWER/THUNDERSTORM ACTIVITY POSSIBLE OVER THE ATLANTIC WATERS
AND EAST COAST METRO AREAS LATER THIS AFTERNOON WITH GREATER
COVERAGE EXPECTED ACROSS THE WESTERN PENINSULA LATE THIS AFTERNOON
WHERE THE SURFACE CONVERGENCE WILL BE MOST DOMINANT. SO OVERALL NO
SIGNIFICANT CHANGES FROM PREVIOUS FORECAST OR SYNOPTIC REASONING
EXCEPT FOR THE VERY SHORT TERM.
60
&&
.PREV DISCUSSION... /ISSUED 728 AM EDT MON SEP 1 2014/
AVIATION...
MOSTLY VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST WITH A
MODERATE EAST WIND FLOW. ANTICIPATED TSRA DEVELOPMENT WILL BE OVER
THE INTERIOR WITH A WESTWARD PROPAGATION. AT THIS TIME, PLACED A
VCTS IN THE KAPF TAF AFT 19Z AND THEY COULD HAVE A BRIEF MVFR OR
EVEN IFR CIG/VSBY THROUGH THE AFTERNOON. EAST FLOW WILL PREVENT A
SEA BREEZE ALONG THE SOUTHWEST COAST BUT WIND IS LIKELY TO VEER TO
THE SSE AS IT TRIES TO FORM.
KOB
PREV DISCUSSION... /ISSUED 329 AM EDT MON SEP 1 2014/
HIGHLIGHTS...
* MODERATE RISK OF RIP CURRENTS ATLANTIC BEACHES
* SLIGHT TSTORM CHANCE EAST COAST, BETTER CHANCE GULF COAST TODAY
* STORMIER PATTERN MID-LATE WEEK; STRONG STORMS POSSIBLE
DISCUSSION...
THE WEATHER PATTERN ON THIS LABOR DAY WILL REMAIN
MOSTLY UNCHANGED FROM YESTERDAY. RIDGE AXIS WILL REMAIN OVER NORTH
FLORIDA, MAINTAINING AN EASTERLY WIND FLOW LOCALLY WITH CONVECTIVE
FOCUS ALONG THE GULF COAST IN THE AFTERNOON. LOW LEVEL WINDS WILL
BE STRONG ENOUGH TO DISALLOW A FULL GULF SEA BREEZE FROM
DEVELOPING, BUT SOME VEERING OF THE WIND FIELD IS EXPECTEDTHERE
WHICH AGAIN WILL LEAD TO ENOUGH CONVERGENCE TO SPARK SOME TSTORM
DEVELOPMENT. ACROSS THE EAST COAST, HRRR SHOWS A SCENARIO SIMILAR
TO YESTERDAY WITH QUICK PASSING SHOWERS DEVELOPING. CANNOT RULE
OUT TSTORMS EAST COAST BUT CONVERGENCE WILL BE LACKING SO COVERAGE
WOULD BE ISOLATED AT BEST.
LIKE YESTERDAY, A LIMITING FACTOR FOR MORE ACTIVE TSTORMS IS THE
LACK OF A FULL FLEDGED ONSHORE GULF SEA BREEZE. HOWEVER, CANNOT
RULE OUT A STRONG TSTORM OR TWO GIVEN SOME CONVERGENCE ALONG WITH
THE INSTABILITY AND CONTINUED DRY AIR ALOFT. WIND GUSTS OF 40-50
MPH IS THE PRIMARY THREAT.
A DEEP LAYERED TROUGH EAST OF THE BAHAMAS IS SHOWN BY THE GLOBAL
MODELS TO MOVE WEST AND ACROSS SOUTH FLORIDA WED NIGHT-THU. THIS
WILL BE ASSOCIATED WITH COOLING ALOFT ALONG WITH INCREASING
MOISTURE, SPELLING A STORMIER PERIOD MID WEEK AND EVEN INTO LATE
WEEK AS HIGHER INSTABILITY REMAINS. POPS ACCORDINGLY SHOW AN
UPWARD TREND MID-LATE WEEK. COULD SEE SOME STRONG STORMS ANYWHERE
BEGINNING WED THROUGH LATE WEEK DUE TO THE COLD AIR ALOFT AND
TROUGH PASSAGE, THOUGH MORE CLOUDINESS WOULD BE A LIMITING FACTOR.
/GREGORIA
AVIATION...
HIGH PRESSURE WILL SLOWLY WEAKEN OVER THE SOUTHEASTERN UNITED
STATES TODAY WHICH IN TURN WILL KEEP A EASTERLY WIND FLOW OF
AROUND 5 KNOTS THROUGH EARLY THIS MORNING AT ALL OF THE TAF SITES.
THE WIND DIRECTION WILL REMAIN EASTERLY AFTER 14Z TODAY BUT
INCREASE TO AROUND 10 KNOTS OVER ALL OF THE TAF SITES.
THE WEATHER SHOULD REMAIN DRY THROUGH THE EARLY MORNING HOURS BEFORE
SOME SHOWERS WORKS INTO THE EAST COAST TAF SITES AFTER 14Z.
SO WILL PUT IN VCSH AFTER 14Z FOR THE EAST COAST TAF SITES. FOR
KAPF TAF SITE...THE WEATHER WILL ALSO REMAIN DRY THROUGH MOST OF
THIS LABOR DAY. HOWEVER...A LATE WEST COAST SEA BREEZE COULD
DEVELOP AND PUSH INTO THE KAPF TAF SITE AFTER 21Z TODAY. SO WILL
PUT IN VCTS BETWEEN 21Z AND 00Z TODAY.
THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS AT ALL
OF THE TAF SITES FOR THIS LABOR DAY.
MARINE...EAST SOUTHEAST WINDS LESS THAN 15 KT WILL PREVAIL AS
THE ATLANTIC RIDGE REMAINS NORTH OF THE LOCAL WATERS. SEAS WILL BE
CORRESPONDINGLY LOW. A TROUGH WILL MOVE ACROSS THE WATERS LATE
WED- THU, BRINGING AN INCREASING CHANCE OF THUNDERSTORMS
ESPECIALLY ACROSS THE ATLANTIC WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 90 79 90 77 / 30 20 40 20
FORT LAUDERDALE 91 80 90 80 / 30 20 50 20
MIAMI 90 80 89 78 / 30 20 50 20
NAPLES 91 76 91 76 / 60 30 60 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...30/KOB
LONG TERM....60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
728 AM EDT MON SEP 1 2014
.AVIATION...
MOSTLY VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST WITH A
MODERATE EAST WIND FLOW. ANTICIPATED TSRA DEVELOPMENT WILL BE OVER
THE INTERIOR WITH A WESTWARD PROPAGATION. AT THIS TIME, PLACED A
VCTS IN THE KAPF TAF AFT 19Z AND THEY COULD HAVE A BRIEF MVFR OR
EVEN IFR CIG/VSBY THROUGH THE AFTERNOON. EAST FLOW WILL PREVENT A
SEA BREEZE ALONG THE SOUTHWEST COAST BUT WIND IS LIKELY TO VEER TO
THE SSE AS IT TRIES TO FORM.
KOB
&&
.PREV DISCUSSION... /ISSUED 329 AM EDT MON SEP 1 2014/
HIGHLIGHTS...
* MODERATE RISK OF RIP CURRENTS ATLANTIC BEACHES
* SLIGHT TSTORM CHANCE EAST COAST, BETTER CHANCE GULF COAST TODAY
* STORMIER PATTERN MID-LATE WEEK; STRONG STORMS POSSIBLE
DISCUSSION...
THE WEATHER PATTERN ON THIS LABOR DAY WILL REMAIN
MOSTLY UNCHANGED FROM YESTERDAY. RIDGE AXIS WILL REMAIN OVER NORTH
FLORIDA, MAINTAINING AN EASTERLY WIND FLOW LOCALLY WITH CONVECTIVE
FOCUS ALONG THE GULF COAST IN THE AFTERNOON. LOW LEVEL WINDS WILL
BE STRONG ENOUGH TO DISALLOW A FULL GULF SEA BREEZE FROM
DEVELOPING, BUT SOME VEERING OF THE WIND FIELD IS EXPECTEDTHERE
WHICH AGAIN WILL LEAD TO ENOUGH CONVERGENCE TO SPARK SOME TSTORM
DEVELOPMENT. ACROSS THE EAST COAST, HRRR SHOWS A SCENARIO SIMILAR
TO YESTERDAY WITH QUICK PASSING SHOWERS DEVELOPING. CANNOT RULE
OUT TSTORMS EAST COAST BUT CONVERGENCE WILL BE LACKING SO COVERAGE
WOULD BE ISOLATED AT BEST.
LIKE YESTERDAY, A LIMITING FACTOR FOR MORE ACTIVE TSTORMS IS THE
LACK OF A FULL FLEDGED ONSHORE GULF SEA BREEZE. HOWEVER, CANNOT
RULE OUT A STRONG TSTORM OR TWO GIVEN SOME CONVERGENCE ALONG WITH
THE INSTABILITY AND CONTINUED DRY AIR ALOFT. WIND GUSTS OF 40-50
MPH IS THE PRIMARY THREAT.
A DEEP LAYERED TROUGH EAST OF THE BAHAMAS IS SHOWN BY THE GLOBAL
MODELS TO MOVE WEST AND ACROSS SOUTH FLORIDA WED NIGHT-THU. THIS
WILL BE ASSOCIATED WITH COOLING ALOFT ALONG WITH INCREASING
MOISTURE, SPELLING A STORMIER PERIOD MID WEEK AND EVEN INTO LATE
WEEK AS HIGHER INSTABILITY REMAINS. POPS ACCORDINGLY SHOW AN
UPWARD TREND MID-LATE WEEK. COULD SEE SOME STRONG STORMS ANYWHERE
BEGINNING WED THROUGH LATE WEEK DUE TO THE COLD AIR ALOFT AND
TROUGH PASSAGE, THOUGH MORE CLOUDINESS WOULD BE A LIMITING FACTOR.
/GREGORIA
AVIATION...
HIGH PRESSURE WILL SLOWLY WEAKEN OVER THE SOUTHEASTERN UNITED
STATES TODAY WHICH IN TURN WILL KEEP A EASTERLY WIND FLOW OF
AROUND 5 KNOTS THROUGH EARLY THIS MORNING AT ALL OF THE TAF SITES.
THE WIND DIRECTION WILL REMAIN EASTERLY AFTER 14Z TODAY BUT
INCREASE TO AROUND 10 KNOTS OVER ALL OF THE TAF SITES.
THE WEATHER SHOULD REMAIN DRY THROUGH THE EARLY MORNING HOURS BEFORE
SOME SHOWERS WORKS INTO THE EAST COAST TAF SITES AFTER 14Z.
SO WILL PUT IN VCSH AFTER 14Z FOR THE EAST COAST TAF SITES. FOR
KAPF TAF SITE...THE WEATHER WILL ALSO REMAIN DRY THROUGH MOST OF
THIS LABOR DAY. HOWEVER...A LATE WEST COAST SEA BREEZE COULD
DEVELOP AND PUSH INTO THE KAPF TAF SITE AFTER 21Z TODAY. SO WILL
PUT IN VCTS BETWEEN 21Z AND 00Z TODAY.
THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS AT ALL
OF THE TAF SITES FOR THIS LABOR DAY.
MARINE...EAST SOUTHEAST WINDS LESS THAN 15 KT WILL PREVAIL AS
THE ATLANTIC RIDGE REMAINS NORTH OF THE LOCAL WATERS. SEAS WILL BE
CORRESPONDINGLY LOW. A TROUGH WILL MOVE ACROSS THE WATERS LATE
WED- THU, BRINGING AN INCREASING CHANCE OF THUNDERSTORMS
ESPECIALLY ACROSS THE ATLANTIC WATERS.
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
329 AM EDT MON SEP 1 2014
.HIGHLIGHTS...
* MODERATE RISK OF RIP CURRENTS ATLANTIC BEACHES
* SLIGHT TSTORM CHANCE EAST COAST, BETTER CHANCE GULF COAST TODAY
* STORMIER PATTERN MID-LATE WEEK; STRONG STORMS POSSIBLE
.DISCUSSION...
THE WEATHER PATTERN ON THIS LABOR DAY WILL REMAIN
MOSTLY UNCHANGED FROM YESTERDAY. RIDGE AXIS WILL REMAIN OVER NORTH
FLORIDA, MAINTAINING AN EASTERLY WIND FLOW LOCALLY WITH CONVECTIVE
FOCUS ALONG THE GULF COAST IN THE AFTERNOON. LOW LEVEL WINDS WILL
BE STRONG ENOUGH TO DISALLOW A FULL GULF SEA BREEZE FROM
DEVELOPING, BUT SOME VEERING OF THE WIND FIELD IS EXPECTEDTHERE
WHICH AGAIN WILL LEAD TO ENOUGH CONVERGENCE TO SPARK SOME TSTORM
DEVELOPMENT. ACROSS THE EAST COAST, HRRR SHOWS A SCENARIO SIMILAR
TO YESTERDAY WITH QUICK PASSING SHOWERS DEVELOPING. CANNOT RULE
OUT TSTORMS EAST COAST BUT CONVERGENCE WILL BE LACKING SO COVERAGE
WOULD BE ISOLATED AT BEST.
LIKE YESTERDAY, A LIMITING FACTOR FOR MORE ACTIVE TSTORMS IS THE
LACK OF A FULL FLEDGED ONSHORE GULF SEA BREEZE. HOWEVER, CANNOT
RULE OUT A STRONG TSTORM OR TWO GIVEN SOME CONVERGENCE ALONG WITH
THE INSTABILITY AND CONTINUED DRY AIR ALOFT. WIND GUSTS OF 40-50
MPH IS THE PRIMARY THREAT.
A DEEP LAYERED TROUGH EAST OF THE BAHAMAS IS SHOWN BY THE GLOBAL
MODELS TO MOVE WEST AND ACROSS SOUTH FLORIDA WED NIGHT-THU. THIS
WILL BE ASSOCIATED WITH COOLING ALOFT ALONG WITH INCREASING
MOISTURE, SPELLING A STORMIER PERIOD MID WEEK AND EVEN INTO LATE
WEEK AS HIGHER INSTABILITY REMAINS. POPS ACCORDINGLY SHOW AN
UPWARD TREND MID-LATE WEEK. COULD SEE SOME STRONG STORMS ANYWHERE
BEGINNING WED THROUGH LATE WEEK DUE TO THE COLD AIR ALOFT AND
TROUGH PASSAGE, THOUGH MORE CLOUDINESS WOULD BE A LIMITING FACTOR.
/GREGORIA
&&
.AVIATION...
HIGH PRESSURE WILL SLOWLY WEAKEN OVER THE SOUTHEASTERN UNITED
STATES TODAY WHICH IN TURN WILL KEEP A EASTERLY WIND FLOW OF
AROUND 5 KNOTS THROUGH EARLY THIS MORNING AT ALL OF THE TAF SITES.
THE WIND DIRECTION WILL REMAIN EASTERLY AFTER 14Z TODAY BUT
INCREASE TO AROUND 10 KNOTS OVER ALL OF THE TAF SITES.
THE WEATHER SHOULD REMAIN DRY THROUGH THE EARLY MORNING HOURS BEFORE
SOME SHOWERS WORKS INTO THE EAST COAST TAF SITES AFTER 14Z.
SO WILL PUT IN VCSH AFTER 14Z FOR THE EAST COAST TAF SITES. FOR
KAPF TAF SITE...THE WEATHER WILL ALSO REMAIN DRY THROUGH MOST OF
THIS LABOR DAY. HOWEVER...A LATE WEST COAST SEA BREEZE COULD
DEVELOP AND PUSH INTO THE KAPF TAF SITE AFTER 21Z TODAY. SO WILL
PUT IN VCTS BETWEEN 21Z AND 00Z TODAY.
THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS AT ALL
OF THE TAF SITES FOR THIS LABOR DAY.
&&
.MARINE...EAST SOUTHEAST WINDS LESS THAN 15 KT WILL PREVAIL AS
THE ATLANTIC RIDGE REMAINS NORTH OF THE LOCAL WATERS. SEAS WILL BE
CORRESPONDINGLY LOW. A TROUGH WILL MOVE ACROSS THE WATERS LATE
WED- THU, BRINGING AN INCREASING CHANCE OF THUNDERSTORMS
ESPECIALLY ACROSS THE ATLANTIC WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 90 79 90 77 / 30 20 40 20
FORT LAUDERDALE 91 80 90 80 / 30 20 50 20
MIAMI 90 80 89 78 / 30 20 50 20
NAPLES 91 76 91 76 / 60 30 60 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...57/DG
LONG TERM....57/DG
AVIATION...54/BNB
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1029 PM EDT TUE SEP 2 2014
.UPDATE...
AFTER AN EARLY START TO CONVECTION OVER THE ATLANTA METRO...FOCUS
QUICKLY SHIFTED TO THE SOUTHEAST ZONES WHERE MIDDLE GEORGIA SAW
NUMEROUS STRONG TO SEVERE THUNDERSTORMS. THIS ACTIVITY HAS SENT AN
OUTFLOW NORTHWARD BACK TO THE METRO BUT NEWLY GENERATED ACTIVITY
HAS BEEN HARD TO COME BY. HRRR DOES INDICATE NW ACTIVITY WILL
SPREAD EASTWARD AND INTERACT WITH AFOREMENTIONED OUTFLOW BUT
REMAINS UNCLEAR IF THIS WILL BE ENOUGH TO GENERATE ADDITIONAL
OVERNIGHT THUNDERSTORM ACTIVITY. FOR NOW...HAVE PLAYED IT AS LOW
END CHANCE POPS IN THE GRIDS FOR MOST LOCATIONS...EXCEPT NORTHWEST
WHERE I HAVE GONE SLIGHTLY HIGHER GIVEN ADDED DYNAMICS IN PLAY.
OTHERWISE FORECAST IS IN GOOD SHAPE AND NO CHANGES ARE PLANNED.
DEESE
&&
.PREV DISCUSSION... /ISSUED 817 PM EDT TUE SEP 2 2014/
PREV DISCUSSION... /ISSUED 301 PM EDT TUE SEP 2 2014/
SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
WEAK IMPULSE IN THE FLOW PUSHING ACROSS THE EASTERN CONUS TODAY AND
THIS MAY HELP THE SHOWERS AND THUNDERSTORMS ACROSS NORTH GEORGIA
CONTINUE INTO TONIGHT. AFTER THIS THOUGH...NO SIGNIFICANT FEATURE AT
THE UPPER LEVELS TO KEY IN ON IN THE SHORT TERM. BASICALLY WILL
CONTINUE AGAIN TOMORROW WITH THE DIURNALLY DRIVEN THUNDERSTORMS IN
THE AFTERNOON AND EVENING. WITH MUCAPE VALUES OVER 2000 J/KG
WEDNESDAY AFTERNOON...STRONG TO ISOLATED SEVERE STORMS WILL BE
POSSIBLE. THE MAIN THREATS TOMORROW AFTERNOON APPEAR TO BE GUSTY
WINDS AND LOCALLY HEAVY RAINFALL.
FAIRLY BIG DISCREPANCIES IN THE TEMPERATURE GUIDANCE FOR TOMORROW
WITH THE MAV BEING WARMER THAN THE MET. AT ATL...THERE IS A SIX
DEGREE TEMPERATURE DIFFERENCE BETWEEN THESE TWO FOR HIGHS TOMORROW
AFTERNOON. MUCH OF THIS IS CAUSED BY MORE CLOUD COVERAGE DEPICTED BY
THE NAM. THINK THE NAM IS OVERDOING CLOUD COVERAGE THOUGH SO STARTED
WITH A BLEND...AND THEN LEANED TOWARDS THE WARMER SIDE FOR HIGH
TEMPS TOMORROW. ONCE AGAIN BOTH HIGH AND LOW TEMPERATURES WILL BE
ABOVE NORMAL.
11
LONG TERM /THURSDAY THROUGH TUESDAY/...
NO CHANGES TO THE CURRENT LONG TERM. SEE PREVIOUS DISCUSSION BELOW...
17
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED 325 AM EDT TUE SEP 2 2014/
SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS EXPECTED
EACH DAY THROUGH THE LONG TERM.
WEAK TROUGH STILL IN PLACE ACROSS CENTRAL GA WEDNESDAY NIGHT...BUT
WILL EVENTUALLY DISSIPATE ON THURSDAY. ALOFT...A WEAK SHEAR AXIS
WILL REMAIN THROUGH FRIDAY. THE DISSIPATING BOUNDARY AND SHEAR AXIS
ALOFT MAY SERVE TO FOCUS ANY CONVECTION THURSDAY INTO FRIDAY.
A WEAK FRONT IS STILL ON TRACK FOR THE MID TO LATE WEEKEND. WITH
SUCCESSIVE RUNS...THE MODELS HAVE SLOWED THE SOUTHWARD PROGRESS OF
THE BOUNDARY. CURRENTLY...THE FRONT SHOULD MOVE ACROSS NORTHERN GA
LATE SATURDAY/EARLY SUNDAY THEN STALL ACROSS CENTRAL GA BY LATE
SUNDAY/EARLY MONDAY. THE FRONT LOOKS TO BECOME DIFFUSE BY TUESDAY.
TEMPS STILL EXPECTED TO BE ABOVE NORMAL THROUGH THE PERIOD.
NLISTEMAA
AVIATION...
00Z UPDATE...
TSRA WHICH AFFECTED THE ATL TERMINALS EARLIER THIS AFTERNOON HAVE
SHIFTED WELL SOUTH TO AFFECT THE SOUTHERNMOST TERMINALS. OUTFLOW
BOUNDARIES COMBINED WITH APPROACHING SEABREEZE MAY KEEP ACTIVITY
IN THE MCN VICINITY THROUGH MIDNIGHT. OTHERWISE...ANOTHER ROUND OF
TSRA WITH SIMILAR TIMING ON WEDNESDAY WARRANTS INCLUSION OF A
PROB30 WHICH WILL IN ALL LIKELIHOOD TRANSITION TO A TEMPO TSRA WITH
SUBSEQUENT FORECASTS.
//ATL CONFIDENCE...00Z UPDATE...
HIGH ON ALL ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 70 95 71 92 / 30 40 30 40
ATLANTA 73 90 73 88 / 30 40 40 40
BLAIRSVILLE 66 86 66 84 / 30 40 30 40
CARTERSVILLE 68 91 69 90 / 40 30 30 40
COLUMBUS 73 94 74 90 / 30 40 40 30
GAINESVILLE 71 90 72 89 / 30 40 30 40
MACON 71 94 71 92 / 60 40 40 30
ROME 68 92 69 91 / 40 30 30 40
PEACHTREE CITY 68 90 70 88 / 50 40 40 40
VIDALIA 73 95 73 92 / 20 40 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DEESE
LONG TERM....30
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
149 PM EDT MON SEP 1 2014
.SYNOPSIS...
SURFACE HIGH PRESSURE WILL EXTEND INTO THE FORECAST AREA FROM THE
ATLANTIC THROUGH THE MIDDLE OF THE WEEK. A PERSISTENT UPPER RIDGE
WILL HELP MAINTAIN THE HOT TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
VISIBLE IMAGERY EARLY THIS AFTERNOON SHOWING LESS CUMULUS COVERAGE
THAN 24 HOURS AGO AND THIS MAY BE ATTRIBUTED TO HIGHER CONVECTIVE
TEMPS IN THE MID 90S TODAY...SOME DRIER AIR NOTED AT 850MB...AND
PRECIPITABLE WATER VALUES AROUND 1.7 INCHES. ENHANCED CUMULUS AND
SOME ISOLATED SHOWERS BEING OBSERVED OVER CENTRAL GEORGIA WHERE
MOISTURE IS BETTER. CURRENTLY WEAK INSTABILITY ACROSS THE AREA
WITH LIFTED INDEX VALUES AROUND -3C TO -5C BUT LAPSE RATES
CONTINUE TO RISE AND ARE UP TO 7.5 C/KM.
SUCCESSIVE RUNS OF THE HRRR CONTINUE TO SHOW LITTLE CONVECTION
OVER THE FORECAST AREA LATE THIS AFTERNOON AND TONIGHT...WHILE THE
LATEST 12Z SPC WRF RUN IS VERY SIMILAR TO ITS 00Z RUN SHOWING
CONVECTION DEVELOPING IN THE CSRA AND WESTERN MIDLANDS LATE
AFTERNOON AND DRIFTING SOUTHEAST AND MERGING WITH SEA BREEZE
CONVECTION OVER THE LOWER CSRA AND SOUTHEASTERN MIDLANDS. WILL
MAINTAIN SLIGHT CHANCE POPS ACROSS THE NORTHERN AND CENTRAL
MIDLANDS WHILE KEEPING LOW CHANCE POPS IN THE MORE FAVORABLE AREA
OF THE CSRA AND SOUTHEASTERN MIDLANDS 21Z-02Z. CANNOT RULE OUT AN
ISOLATED SEVERE THUNDERSTORM AND WEAK STORM MOTION WILL PROVIDE A
LOCALLY HEAVY RAIN AND POSSIBLE FLOODING THREAT WHERE STORMS TRAIN
OR REMAIN NEARLY STATIONARY. EXPECT SOME CONVECTIVE DEBRIS CLOUDS
AROUND OVERNIGHT WHICH WILL HELP LIMIT FOG POTENTIAL AND EXPECT
OVERNIGHT LOWS IN THE MID 70S.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
SURFACE RIDGING SHOULD CONTINUE EAST AND SOUTH OF THE FORECAST
AREA. EXPECT WEAK LEE-SIDE TROUGHING IN THE AREA. STRONG HEATING
AND CONVERGENCE INTO THIS FEATURE SHOULD HELP SUPPORT
THUNDERSTORMS...BUT CONTINUED UPPER RIDGING SHOULD LIMIT COVERAGE.
ALSO...THE SURFACE FEATURE SHOULD REMAIN WEAK. THE NAM AND GFS
MOS HAVE LOW POPS WITH THE CONSENSUS AROUND 20 PERCENT. IT WILL
REMAIN HOT. USED THE WARMER TEMPERATURE GUIDANCE BASED ON RECENT
VERIFICATION.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE GFS AND ECMWF SHOW A WEAKENING FRONT STALLING BEFORE REACHING
THE AREA DURING THE MIDDLE OF THE WEEK. THE MODELS SHOW ANOTHER
FRONT MAY REACH THE AREA LATE IN THE MEDIUM-RANGE PERIOD. THE
MODELS INDICATE UPPER-LEVEL RIDGING CONTINUING. THE
GFS...ECMWF...AND EKD MOS SHOW ABOVE NORMAL TEMPERATURES WITH POPS
20 TO 30 PERCENT THROUGH THE PERIOD.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
HIGHER CONVECTIVE TEMPS TODAY ALONG WITH SOME DRIER AIR AT 850MB
HAS RESULTED IN A LATER START TO THE CUMULUS DEVELOPMENT BUT IT IS
UNDERWAY WITH WEAK TO MODERATE INSTABILITY IN PLACE. ISOLATED
CONVECTION IS EXPECTED BUT LOW CONFIDENCE IN ANY STORMS IMPACTING
TERMINALS SO NOT IN THE FORECAST AT THIS TIME. EXPECT VFR
CONDITIONS THROUGHOUT THE FORECAST PERIOD EXCEPT FOR SOME MVFR FOG
AT FOG PRONE AGS/OGB...FOG APPEARS LESS LIKELY AT CAE/CUB/DNL.
LIGHT SOUTHERLY WINDS THIS AFTERNOON WILL BECOME NEAR CALM
OVERNIGHT AND PICK UP FROM THE SOUTH AGAIN AFTER 15Z TUESDAY...LESS
THAN 5 KNOTS.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN LATE NIGHT
AND EARLY MORNING STRATUS AND FOG. SCATTERED MAINLY AFTERNOON
SHOWERS AND THUNDERSTORMS TUESDAY THROUGH SATURDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
NEAR TERM...HC
AVIATION...HC
AREA FORECAST DISCUSSION...UPDATED
NWS COLUMBIA SC
1106 AM EDT MON SEP 1 2014
.SYNOPSIS...
SURFACE HIGH PRESSURE WILL EXTEND INTO THE FORECAST AREA FROM THE
ATLANTIC THROUGH THE MIDDLE OF THE WEEK. A PERSISTENT UPPER RIDGE
WILL HELP MAINTAIN THE HOT TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NOT MUCH HAS CHANGED IN THE ATMOSPHERE OVER THE PAST 24 HOURS
REGARDING THE OVERALL WEATHER PATTERN OVER THE REGION. SURFACE
HIGH PRESSURE CENTERED OVER THE WESTERN ATLANTIC WILL CONTINUE TO
RIDGE INTO THE FORECAST AREA TODAY WITH GENERALLY MOIST SOUTHERLY
FLOW. IN THE UPPER LEVELS...THE RIDGE AXIS HAS SHIFTED SLIGHTLY TO
THE EAST TOWARDS THE COAST IN RESPONSE TO SHORTWAVE ENERGY PUSHING
INTO THE OHIO/TENNESSEE VALLEYS. MORNING MESOANALYSIS SHOWS A
PRECIPITABLE WATER GRADIENT ACROSS THE REGION FROM 1.5 INCHES IN
THE WESTERN MIDLANDS TO 1.8 INCHES IN THE EASTER MIDLANDS WITH A
POCKET OF DRY AIR AROUND 850MB IN THE UPSTATE INTO THE WESTERN
MIDLANDS.
DESPITE THE UPPER RIDGING OVER THE REGION...THE NAM SHOWS A
SHORTWAVE TROUGH MOVING INTO THE RIDGE OVER THE FORECAST AREA
LATE THIS AFTERNOON AND EVENING. THE COMBINATION OF STRONG
HEATING...WEAK CONVERGENCE INTO THE LEE-SIDE TROUGH...AND ABUNDANT
LOW LEVEL MOISTURE IN PLACE SHOULD SUPPORT LATE DAY THUNDERSTORM
DEVELOPMENT...ALTHOUGH UNCERTAINTY REMAINS ABOUT THE OVERALL
COVERAGE. THE SPC WRF SHOWS SCATTERED COVERAGE IN THE AFTERNOON
BECOMING WIDESPREAD DURING THE EVENING...WHILE THE LATEST HRRR AND
LOCAL OFFICE HI-RES WRF ARE VERY LIMITED WITH ANY CONVECTION.
WILL FAVOR HIGHEST POPS...CHANCE 30-40 PERCENT...IN THE
SOUTHEASTERN MIDLANDS AND CSRA WITH SLIGHT CHANCE POPS ELSEWHERE
LATE AFTERNOON INTO THE EVENING. SLOW STORM MOTION AND
RECOVERING PRECIPITABLE WATER VALUES NEAR 2 INCHES WILL SUPPORT
LOCALLY HEAVY RAIN. CANNOT RULE OUT AN ISOLATED SEVERE STORM OR
TWO OR LOCALIZED FLOODING DUE TO MODERATE INSTABILITIES.
TEMPERATURES ARE QUICKLY RISING AGAIN THROUGH THE UPPER 80S AT
THIS TIME AND WILL REACH THE MID TO UPPER 90S AGAIN TODAY. WENT
ABOVE MOS GUIDANCE WHICH HAS SHOWN A COOL BIAS FOR SEVERAL DAYS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
SURFACE RIDGING SHOULD CONTINUE EAST AND SOUTH OF THE FORECAST
AREA. EXPECT WEAK LEE-SIDE TROUGHING IN THE AREA. STRONG HEATING
AND CONVERGENCE INTO THIS FEATURE SHOULD HELP SUPPORT
THUNDERSTORMS...BUT CONTINUED UPPER RIDGING SHOULD LIMIT COVERAGE.
ALSO...THE SURFACE FEATURE SHOULD REMAIN WEAK. THE NAM AND GFS
MOS HAVE LOW POPS WITH THE CONSENSUS AROUND 20 PERCENT. IT WILL
REMAIN HOT. USED THE WARMER TEMPERATURE GUIDANCE BASED ON RECENT
VERIFICATION.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE GFS AND ECMWF SHOW A WEAKENING FRONT STALLING BEFORE REACHING
THE AREA DURING THE MIDDLE OF THE WEEK. THE MODELS SHOW ANOTHER
FRONT MAY REACH THE AREA LATE IN THE MEDIUM-RANGE PERIOD. THE
MODELS INDICATE UPPER-LEVEL RIDGING CONTINUING. THE
GFS...ECMWF...AND EKD MOS SHOW ABOVE NORMAL TEMPERATURES WITH POPS
20 TO 30 PERCENT THROUGH THE PERIOD.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
SOME LINGERING CONVECTIVE DEBRIS CLOUDS AROUND THE AREA BUT VFR
CONDITIONS ARE EXPECTED THROUGH MUCH OF THE FORECAST PERIOD
OUTSIDE OF SCATTERED SHOWERS AND THUNDERSTORMS WHICH MAY IMPOSE
BRIEF MVFR/IFR CONDITIONS. THE CONFIDENCE IN ANY STORMS IMPACTING
ANY TERMINAL IS LOW AND THEREFORE NOT FORECAST AT THIS TIME BUT
SCATTERED CONVECTION IS EXPECTED AFTER 20Z. LIGHT AND VARIABLE
WINDS WILL BECOME MORE SOUTHERLY BY AFTERNOON BEFORE GOING LIGHT
AND VARIABLE TO CALM AGAIN OVERNIGHT.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN LATE NIGHT
AND EARLY MORNING STRATUS AND FOG. SCATTERED MAINLY AFTERNOON
SHOWERS AND THUNDERSTORMS TUESDAY THROUGH FRIDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
NEAR TERM...HC
AVIATION...HC
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
104 PM CDT MON SEP 1 2014
.DISCUSSION...
1115 AM CDT
FOR MORNING UPDATE...
THUNDERSTORM AND SEVERE WEATHER THREAT APPEARS TO HAVE DIMINISHED
SIGNIFICANTLY FOR MUCH OF THE FORECAST AREA TODAY...DUE TO CLOUD
COVER AND DRIER AIR WHICH HAS SPREAD EAST ACROSS NORTHERN IL WITH
OUTFLOW FROM OVERNIGHT MCS TO OUR WEST. SEE UPDATED SPC DAY 1
OUTLOOK WHICH REMOVES SLIGHT RISK GENERALLY ALONG/WEST OF I-57.
HAVE ALSO BOOSTED TEMPS ACROSS THE SOUTHEAST TO THE LOW-MID 80S
WHERE TEMPS QUICKLY WARMING.
LEAD SHORT WAVE...POSSIBLY ENHANCED BY MCS/MCV FROM NOCTURNAL MCS
OVER IOWA...HAS MOVED INTO NORTHERN IL THIS MORNING ACCOMPANIED BY A
PRE-FRONTAL TROUGH AND SHIFT TO WESTERLY WINDS GENERALLY WEST OF THE
FOX RIVER VALLEY AS OF 11 AM. EXTENSIVE CLOUD COVER..AND LOWER SFC
DEW POINTS BEHIND THE BOUNDARY HAVE STABILIZED ATMOSPHERE...WITH
HIGHER THETA-E AIR CHARACTERIZED BY LOWER 70S DEW POINT TEMPS NOW
MAINLY ALONG/EAST OF THE INTERSTATE 57 CORRIDOR. WHILE SOME EROSION
OF CLOUD COVER WAS NOTED ACROSS WESTERN IL...IT APPEARS THAT THE
MAIN INSTABILITY AXIS WILL BE ACROSS THE FAR EASTERN CWA AND AREAS
FARTHER EAST. HIGH-RES CONVECTION ALLOWING GUIDANCE INCLUDING THE
HRRR AND NATIONAL/LOCAL ARW RUNS INDICATE LITTLE IN THE WAY OF
ROBUST CONVECTION DEVELOPING ACROSS NORTHERN IL...WITH DIURNAL
DESTABILIZATION AND STRONGER THUNDERSTORM INITIATION FOCUSED EARLY
THIS AFTERNOON ALONG OUR EASTERN CWA BOUNDARY. THUS IT APPEARS OUR
SEVERE WEATHER THREAT HAS DECREASED SIGNIFICANTLY...AND SPC HAS
REMOVED MUCH OF THE CWA WEST OF I-57 FROM THEIR DAY 1 SLIGHT RISK.
THE SYNOPTIC COLD FRONT STILL REMAINS TO OUR WEST...FROM JUST EAST
OF THE TWIN CITIES TO SOUTHWEST IOWA AT 11 AM...AND THIS WILL MOVE
EAST THROUGH THE AFTERNOON AND EVENING. GUIDANCE DOES DEPICT A LINE
OF SHOWERS/ISOLATED THUNDERSTORMS DEVELOPING AHEAD OF THE FRONT LATE
THIS AFTERNOON AND EVENING...THOUGH SEVERE THREAT APPEARS VERY LOW
IN RATHER WEAK MLCAPE ENVIRONMENT. POTENTIAL FOR STRONGER STORM
DEVELOPMENT DOES REMAIN LATER TONIGHT ALONG THE FRONT AS MAIN SHORT
WAVE MOVES ACROSS THE AREA...THOUGH TRENDS FROM 12Z GUIDANCE
INDICATE ONLY A SMALL PORTION OF OUR SOUTHEAST CWA MAY BE
AFFECTED. HAVE TRIMMED BACK POPS QUITE A BIT ACROSS THE NORTHERN
3/4 OR SO OF THE CWA AND MAY BE ABLE TO TRIM EVEN FURTHER
DEPENDING ON TRENDS OVER THE NEXT FEW HOURS.
RATZER
//PREV DISCUSSION...
340 AM CDT
ENTERING SEPTEMBER AND METEOROLOGICAL AUTUMN WE STILL FIND THE
FORECAST CHALLENGES TO BE MORE SUMMER-LIKE...AT LEAST EARLY ON IN
THE FORECAST. THAT IS STORM AND HEAVY RAIN POTENTIAL TODAY AND
TONIGHT...THEN STORM CHANCES WEDNESDAY NIGHT AND FRIDAY WHICH
SANDWICH A POSSIBLE 90 PLUS DEGREE DAY ON THURSDAY. LESS BUT
STILL SOME TIME WAS SPENT ON THE FINAL CHALLENGE OF HOW MUCH OF A
COOL DOWN OCCURS THE FIRST FULL WEEKEND OF THIS NEW METEOROLOGICAL
SEASON.
SYNOPSIS...
A LONG WAVE TROUGH EXTENDING SOUTHWARD THROUGH CANADA INTO THE NORTH
CENTRAL U.S. HAS A VERY PROGRESSIVE SHORT WAVE FEATURE MOVING
THROUGH ITS SOUTHERN BASE. THIS IS SPEEDING EAST-NORTHEAST ACROSS
IA EARLY THIS MORNING. A SURFACE COLD FRONT MOVING EAST LAGS THIS
SHORT WAVE...EXTENDING FROM NORTHERN MN THROUGH THE TX PANHANDLE
EARLY THIS MORNING...WITH MULTIPLE SURFACE WAVES IN THE 1003MB
NEIGHBORHOOD ALONG IT. NORTHWEST SURFACE FLOW BEHIND THIS FRONT IS
NOT PARTICULARLY STRONG SO THIS FRONT WILL CONTINUE TO BE A SLOW-
MOVER TODAY...NOT EXPECTED TO ENTER THE FORECAST AREA UNTIL THIS
EVE. BEING WITHIN A WARM SECTOR UNDER QUICKENING UPPER/MID-LEVEL
FLOW PRESENTS THE STORM CHANCES THESE 24 HOURS.
THIS MORNING...
A LOOSELY DEFINED MCS MOVING EASTWARD INTO NORTHWEST IL EARLY THIS
MORNING WANED CONSIDERABLY WITH WARMING CLOUD TOPS AND OUTFLOW
EXTENDING WELL AHEAD OF IT. SEEING AN UPTICK ACROSS WEST CENTRAL IL
LIKELY ASSOCIATED WITH LIFT OF THE AFOREMENTIONED PROGRESSIVE SHORT
WAVE. HIGH RESOLUTION MODELS GREATLY VARY ON WHAT WILL HAPPEN EVEN
JUST A FEW HOURS OUT...BUT WOULD EXPECT SYNOPTICALLY TO SEE SOME
CONVECTION EVOLVE INTO THE FORECAST AREA THIS MORNING...POSSIBLY
ONLY THE WESTERN/SOUTHWESTERN AREA BUT STILL CANT RULE OUT SCATTERED
ACTIVITY MOVING EASTWARD THROUGH THE ENTIRE AREA INCLUDING
CHICAGO DURING MID/LATE MORNING. DESPITE A FAIRLY STRONG LOW-LEVEL
JET INTO ANY ACTIVITY...THE CONTINUED BROAD AREA OF STORMS ACROSS
EASTERN KS INTO WEST/SOUTHWEST MO THROUGH EARLY TO MID MORNING
SHOULD LESSEN MOISTURE TRANSPORT AND THUS ABILITY TO REALIZE STEEP
LAPSE RATES ALOFT FOR MORE ROBUST ACTIVITY...AND MAYBE EVEN
THUNDER IN GENERAL NORTH OF INTERSTATE 80.
THIS AFTERNOON AND TONIGHT...
DESPITE THIS BEING IN THE FIRST 12 HOURS OF THE FORECAST...DUE TO
INFLUENCE OF MORNING STORMS AND LARGE MODEL DIFFERENCES...CONFIDENCE
ON SPECIFICS IN THESE PERIODS REMAIN LOW. THERE SHOULD BE SOME
FORM OF OUTFLOW BOUNDARY OR BOUNDARIES FROM MORNING ACTIVITY/CLOUD
COVER THAT LINGER INTO THE FORECAST AREA INTO THE AFTERNOON...MOST
FAVORED SOUTH OF INTERSTATE 80. AS WARMING AND DESTABILIZATION
OCCURS WITH DEW POINTS AROUND 70F...COULD SEE SCATTERED ACTIVITY
DEVELOP NEAR ANY SUCH BOUNDARIES DURING THE MID TO LATE AFTERNOON.
THE SECOND UPPER WAVE ACROSS WESTERN WY THIS MORNING WILL BEGIN TO
APPROACH THE REGION AS WELL BY LATE IN THE DAY...WITH FORCING FROM
THIS POSSIBLY AIDING IN SCATTERED STORM DEVELOPMENT ACROSS MUCH OF
THE REGION. EVEN EARLY THIS MORNING THERE ARE A HANDFUL OF STORMS
ACROSS THE UPPER MIDWEST NOT LINKED TO ANY SPECIFIC SURFACE
FEATURE. INCREASING DEEP LAYER SHEAR OF 35 TO 50 KT WILL SUPPORT
ISOLATED TO SCATTERED SEVERE DISCRETE STORMS IN THE REGION.
WHILE IT REMAINS DIFFICULT TO PINPOINT TIMING...IT WOULD SEEM THE
GREATEST COVERAGE IN REDEVELOPING STORMS THIS EVENING WOULD BE IN
THE SOUTHERN FORECAST AREA WHERE AFOREMENTIONED BOUNDARY MAY OCCUR
AND MODEST SOUTHWEST 850-925MB FLOW AND MOISTURE TRANSPORT
REMAINS. AS THE AREA BECOMES UNDER A RIGHT ENTRANCE REGION TO THE
UPPER JET...DO EXPECT INCREASING ASCENT TONIGHT IN THE REGION FOR
MORE ROBUST CONVECTION AND POTENTIAL SEVERE AND HEAVY RAIN
THREATS. RIGHT NOW A GUIDANCE OVERLAP WOULD INDICATE THE FAR
SOUTHEAST FORECAST AREA IS MOST FAVORED FOR THIS. PRECIPITABLE
WATERS AROUND TWO INCHES AND STORM MOTIONS NEARLY PARALLEL TO THE
UPPER AND MID LEVEL FLOW WILL PRESENT HEAVY RAIN THREATS IN
THE GENERAL CENTRAL TO SOUTHERN IL INTO IN REGIONS...BUT AGAIN AT
THIS TIME CONFIDENCE VARIES ON PLACEMENT. BECAUSE OF THAT WILL
CONTINUE WITH THE HYDROLOGIC OUTLOOK /ESF/ FOR THE AREAS HIT HARD
ON SATURDAY NIGHT WITH HEAVY RAINFALL.
TUESDAY AND WEDNESDAY...
THE FRONT SHOULD CLEAR THE FORECAST AREA SOMETIME TUESDAY MORNING.
WHILE DRY AIR ADVECTION WILL OCCUR...LIMITED CONVERGENCE REMAINS
IN THE SOUTHEAST FORECAST AREA FOR POSSIBLY A STORM OR TWO TUESDAY
BUT IT LOOKS TO BE A LOW CHANCE. TEMPERATURES ONLY COOL SLIGHTLY
AS HIGH PRESSURE QUICKLY MOVES ATOP THE AREA TUESDAY NIGHT AND
THEN EASTWARD.
WEDNESDAY NIGHT THROUGH FRIDAY...
WARM AIR ADVECTION AND A RAPID PRECIPITABLE WATER INCREASE IS
FORECAST WEDNESDAY NIGHT ON ALL GUIDANCE. FEEL THAT MODELS MAY BE
UNDER-DOING THE STORM CHANCES GIVEN FORECAST PROFILES OF STEEPENING
LAPSE RATES WITHIN A RAPIDLY MOISTENING COLUMN...AT LEAST IN THE
WESTERN FORECAST AREA. SO HAVE INCREASED POPS IN THAT AREA. AS FOR
THURSDAY...HAVE GONE DRY IN MANY AREAS COLLABORATING AND
UNDERCUTTING A MODEL BLEND OF POPS. THE SYNOPTIC PATTERN FAVORS A
HOT DAY AND BARRING ANY STRATUS ISSUES WITH WEDNESDAY NIGHTS WARM
AIR ADVECTION AND POSSIBLE PRECIP...SHOULD SEE THE 90 DEGREE MARK
REACHED OR EXCEEDED ACROSS A GOOD PART OF THE FORECAST AREA BASED
ON STRONG SOUTHWEST FLOW AND FORECAST 850MB AND 925MB TEMPERATURES
COMPARED TO CLIMATOLOGY. FOR NOW HAVE KEPT THE NORTH A LITTLE
BELOW THAT WITH THE POSSIBILITY OF MORNING CLOUDS. THE SYSTEM
COLD FRONT IS PRESENTLY FORECAST BY THE EC AND THE GFS TO COME
THROUGH THE AREA SOMETIME ON FRIDAY WHICH WOULD BRING STORM
CHANCES WITH IT...AS WELL AS FLOW TURNING OFF THE LAKE BEHIND ITS
PASSAGE.
BEYOND...
NO CHANGES MADE TO THIS WEEKEND WHERE HIGHS LOOK TO BE AROUND 70
WITH DRY CONDITIONS BEHIND THE AFOREMENTIONED FRONT. HIGH PRESSURE
AROUND 1023MB IS FORECAST BY A BLEND OF GUIDANCE. GIVEN THE 925MB
TEMPERATURES FORECAST IF THAT HIGH IS CENTERED OVER THE FORECAST
AREA SOMETIME SUNDAY OR MONDAY NIGHTS /7TH OR 8TH/...LOWS IN
OUTLYING AREAS WOULD LIKELY BE IN THE 40S.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* TSRA CHANCES THIS AFTERNOON AND EVENING.
* CEILING TRENDS THIS AFTERNOON.
* MORE SHRA AND TSRA POSSIBLE TOWARD EVENING.
LENNING
//DISCUSSION...UPDATED 18Z...
CONVECTION HAS BLOSSOMED ALONG A LINE OVER LOWER MI BUT MANAGED TO
AVOID MOST OF THE LOCAL AREA THIS MORNING. AN ADDITIONAL CLUSTER
OF STORMS IS STARTING TO FORM OVER NORTHEAST IOWA ALONG A COLD
FRONT THAT IS MOVING THIS DIRECTION. TIMING OF THE IOWA ACTIVITY
INTO THE LOCAL AREA IS UNCERTAIN...BUT FEEL THAT 00Z TO 03Z
IS A GOOD FIRST ESTIMATE AT ORD AND MDW AS PER 18Z TAF.
CEILINGS HAVE SCATTERED EXCEPT FOR SOME LINGERING MVFR...BUT AM
NOT CONFIDENT THAT SCT-CLR SKIES WILL BE WIDESPREAD THIS
AFTERNOON GIVEN THE AMOUNT OF MOISTURE IN THE AIR. AREAS THAT HAD
CLEARED EARLIER ARE ALREADY STARTING TO FILL BACK IN WITH DIURNAL
HEATING...BUT FOR THE MOST PART ARE STAYING VFR.
OVERNIGHT TOWARD MORNING THERE IS A CHANCE OF LOWER VSBYS WITH
LIGHT WINDS AND MOIST AIR IN PLACE...BUT GUIDANCE SHOWS BETTER
CHANCES TOWARD RFD THAN IN THE MDW/ORD TERMINALS...LIKELY DUE TO
BETTER COOLING THAN IN THE CITY. HAVE NOT PUT THIS IN THE TAFS YET
BUT WILL MONITOR FOR LATER INCLUSION.
LENNING
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE FOR ALL ELEMENTS.
LENNING
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT THROUGH THURSDAY...PREDOMINANTLY VFR.
FRIDAY...CHANCE OF SHRA/TSRA.
SATURDAY AND SUNDAY...PREDOMINANTLY VFR.
KJB
&&
.MARINE...
232 AM CDT
IT LOOKS TO BE AN ACTIVE WEATHER DAY ACROSS THE LAKE...WITH STOUT
SOUTHERLY WINDS LAKE-WIDE...AND THE THREAT FOR SOME STRONG TO SEVERE
THUNDERSTORMS ACROSS SOUTHERN LAKE MICHIGAN. THESE STRONG SOUTHERLY
WINDS WILL RESULT IN WINDS AROUND 25 KT AND THE ONGOING SMALL CRAFT
ADVISORY STILL APPEARS GOOD. THE SURFACE LOW...RESPONSIBLE FOR THESE
STRONG SOUTHERLY WINDS TODAY...WILL SHIFT ACROSS ONTARIO...AND TO
NEAR JAMES BAY BY THIS EVENING WHILE DEEPENING TO AROUND 29.2
INCHES. AS THIS OCCURS...AN ASSOCIATED COLD FRONT WILL BE DRAWN
EASTWARD ACROSS THE LAKE BY EARLY TUESDAY MORNING. WINDS WILL BECOME
WESTERLY AND ABATE SIGNIFICANTLY WITH THE PASSAGE OF THIS FRONT.
ANOTHER PERIOD OF STRONGER SOUTHERLY WINDS LOOKS TO SET UP AGAIN
WEDNESDAY NIGHT AND THURSDAY AS ANOTHER POTENT AREA OF LOW PRESSURE
TRACKS EASTWARD ACROSS ONTARIO. WINDS SPEEDS COULD AGAIN BE AROUND
25 KT OUT OF THE SOUTH DURING THIS PERIOD. ANOTHER STRONGER COLD
FRONT LOOKS TO SHIFT DOWN THE LAKE IN THE WAKE OF THIS LOW LATE
FRIDAY AND THIS COULD SET THE STAGE FOR A DECENT NORTHERLY WIND
EVENT ACROSS THE LAKE AS A STOUT AREA OF HIGH PRESSURE QUICKLY
BUILDS EASTWARD ACROSS THE UPPER MIDWEST. STRONG NORTHERLY WINDS OF
25 TO 30 KT APPEAR QUITE POSSIBLE IN THE WAKE OF THIS COLD FRONT
FRIDAY NIGHT INTO SATURDAY...WHICH WOULD ALSO RESULT IN LARGE WAVES
IN EXCESS OF 5 FEET ACROSS SOUTHERN LAKE MICHIGAN INTO NEXT
WEEKEND.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM MONDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1249 PM CDT Mon Sep 1 2014
.UPDATE...
ISSUED AT 1001 AM CDT MON SEP 1 2014
Line of strong to severe thunderstorms tracked across Iowa last
night, then rapidly dissipated as it pushed toward the
Mississippi River early this morning. Outflow boundary from this
dying convection is currently approaching the I-55 corridor
as evidenced by westerly winds across all sites in the Illinois
River Valley. Think this outflow will eventually serve as the
primary focus for additional thunderstorm development later today.
Still some question as to exactly where the boundary will lay out
and when convection will fire, but the latest thinking from SPC
has pushed the best severe weather risk much further southeast,
generally along/south of a Danville to Jacksonville line. HRRR is
performing very poorly this morning and its solution has been
completely disregarded. Meanwhile, the 12z NAM seems to have at
least a reasonable handle on the situation, showing storms
developing by early afternoon near I-55, then shifting further
east and south later in the day. Will continue to monitor
stability parameters to see if projected 1500 to 2500J/kg CAPEs
can be realized. If the airmass destabilizes as predicted,
increasing shear values will help storms organize and potentially
produce large hail and damaging winds this afternoon into this
evening. Am still concerned about the threat for heavy rainfall
across the E/SE CWA tonight as favorable jet dynamics produce
enhanced synoptic lift along/ahead of approaching cold front. As
storms become parallel to upper flow, training appears likely
tonight along/south of a Danville to Jacksonville line. Latest NAM
continues to put down some hefty rainfall totals across this area.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 355 AM CDT MON SEP 1 2014
Shortwave trough axis approaching Illinois from the west this
morning bringing a line of thunderstorms to the region. Trends this
morning are for the line splitting into to intense lines...one
grazing Knox, Peoria, Stark county and likely Marshall and Woodford
as it continues this morning. Have reports of pea-sized hail and
wind gusts 30-40 mph with the more intense storm cells. The intense
activity looks like it will have a break through central IL in the
early morning once this initial activity shifts east-northeastward.
Isolated thunderstorms will likely develop throughout the CWA during
the morning...however daytime heating will likely be necessary to
bring CAPE values up to 1500-2500 J/KG range to bring a better
chance for severe storms when combined with 30-50 kt bulk shear
values also shifting into central Illinois. Large hail and severe
wind gusts will be a threat with the stronger storms this
afternoon...and have continued mention of severe hail and heavy rain
in forecast grids beginning at 3 pm this afternoon...continuing
through around midnight. Heavy rain will continue through the night
as a potent and moist low-level jet continues to push through the
CWA...along with lift associated with the progressive trough and
cold frontal boundary.
&&
.LONG TERM...(Tuesday through Sunday)
ISSUED AT 355 AM CDT MON SEP 1 2014
00Z models have trended slower with frontal boundary pushing into
southeast IL Tue especially the NAM model and have increase pops to
likely se of I-70 Tue morning. NAM model may be overdoing qpf
amounts Tue morning over southeast IL but models have trended higher
with qpf amounts with precipitable water values of 1.5-2 inches
from 12-15Z Tue and have increased qpf amounts to around a quarter
inch in southeast IL. IL river valley should be dry Tue and chances
of showers and thunderstorms will diminish from nw to se during
Tue afternoon. Highs 82-88F Tue and still rather humid especially
in southeast IL with dewpoints 70-75F while dewpoints lower into
mid 60s over IL river valley. Dry conditions return across area
Tue night with frontal boundary dropping south of area. Lows in
the low to mid 60s Tue night.
Models show frontal boundary starting to lift back north especially
over MS river valley and MO on Wed and have kept 20-30% chance of
showers and thunderstorms sw areas by Wed afternoon with ne areas
staying dry Wed. Warm highs in the mid to upper 80s Wed and model
guidance has trended upward in high temps Wed. Dewpoints elevate
during day Wed into upper 60s and lower 70s Wed afternoon.
Convection chances appear highest over northern IL Wed night closer
to short waves tracking into WI/northern IL and eventually eastward
into lower MI and northern IN. Have areas south of I-72 dry Wed
night.
Thu and Fri still appear to be back into the heat and humidity with
highs in the upper 80s and lower 90s and dewpoints peaking in the
low to mid 70s giving afternoon heat indices of upper 90s to lower 100s
especially Thu afternoon and in southeast IL Friday afternoon. A 593
dm 500 mb high pressure ridge over the southeast states builds the
heat into central/southeast IL late this work week. Most of our area
should be dry Thu and Thu night with just slight chance of
convection Thu afternoon mainly over the Wabash river valley and
nw of IL river Thu night. Models have trended faster with cold
front dropping se through central IL Friday and thru southeast IL
Fri evening. Have increased pops Friday and also trending cooler
with temps and dewpoints during the weekend as 1025 mb high
pressure settles into the Great Lakes region.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1248 PM CDT MON SEP 1 2014
Convective development/evolution remains in question, as previous
outflow boundary has pushed east of the I-55 corridor early this
afternoon. Most model solutions are keeping central Illinois
largely dry through the afternoon, with thunderstorms
developing/increasing after dark across the south. Based on 12z
NAM and latest HRRR, it appears the axis of heavy rain will be
focused along the I-70 corridor between 05z and 12z. As such, have
kept both KPIA and KBMI dry through the entire 18z TAF period.
Further south, have introduced -RA with VCTS at the remaining
terminals after 05/06z, thinking they may be on the northern
fringe of the low-level jet enhanced precip area overnight.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BARNES
SHORT TERM...ONTON
LONG TERM...07
AVIATION...BARNES
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1115 AM CDT MON SEP 1 2014
.DISCUSSION...
340 AM CDT
ENTERING SEPTEMBER AND METEOROLOGICAL AUTUMN WE STILL FIND THE
FORECAST CHALLENGES TO BE MORE SUMMER-LIKE...AT LEAST EARLY ON IN
THE FORECAST. THAT IS STORM AND HEAVY RAIN POTENTIAL TODAY AND
TONIGHT...THEN STORM CHANCES WEDNESDAY NIGHT AND FRIDAY WHICH
SANDWICH A POSSIBLE 90 PLUS DEGREE DAY ON THURSDAY. LESS BUT
STILL SOME TIME WAS SPENT ON THE FINAL CHALLENGE OF HOW MUCH OF A
COOL DOWN OCCURS THE FIRST FULL WEEKEND OF THIS NEW METEOROLOGICAL
SEASON.
SYNOPSIS...
A LONG WAVE TROUGH EXTENDING SOUTHWARD THROUGH CANADA INTO THE NORTH
CENTRAL U.S. HAS A VERY PROGRESSIVE SHORT WAVE FEATURE MOVING
THROUGH ITS SOUTHERN BASE. THIS IS SPEEDING EAST-NORTHEAST ACROSS
IA EARLY THIS MORNING. A SURFACE COLD FRONT MOVING EAST LAGS THIS
SHORT WAVE...EXTENDING FROM NORTHERN MN THROUGH THE TX PANHANDLE
EARLY THIS MORNING...WITH MULTIPLE SURFACE WAVES IN THE 1003MB
NEIGHBORHOOD ALONG IT. NORTHWEST SURFACE FLOW BEHIND THIS FRONT IS
NOT PARTICULARLY STRONG SO THIS FRONT WILL CONTINUE TO BE A SLOW-
MOVER TODAY...NOT EXPECTED TO ENTER THE FORECAST AREA UNTIL THIS
EVE. BEING WITHIN A WARM SECTOR UNDER QUICKENING UPPER/MID-LEVEL
FLOW PRESENTS THE STORM CHANCES THESE 24 HOURS.
THIS MORNING...
A LOOSELY DEFINED MCS MOVING EASTWARD INTO NORTHWEST IL EARLY THIS
MORNING WANED CONSIDERABLY WITH WARMING CLOUD TOPS AND OUTFLOW
EXTENDING WELL AHEAD OF IT. SEEING AN UPTICK ACROSS WEST CENTRAL IL
LIKELY ASSOCIATED WITH LIFT OF THE AFOREMENTIONED PROGRESSIVE SHORT
WAVE. HIGH RESOLUTION MODELS GREATLY VARY ON WHAT WILL HAPPEN EVEN
JUST A FEW HOURS OUT...BUT WOULD EXPECT SYNOPTICALLY TO SEE SOME
CONVECTION EVOLVE INTO THE FORECAST AREA THIS MORNING...POSSIBLY
ONLY THE WESTERN/SOUTHWESTERN AREA BUT STILL CANT RULE OUT SCATTERED
ACTIVITY MOVING EASTWARD THROUGH THE ENTIRE AREA INCLUDING
CHICAGO DURING MID/LATE MORNING. DESPITE A FAIRLY STRONG LOW-LEVEL
JET INTO ANY ACTIVITY...THE CONTINUED BROAD AREA OF STORMS ACROSS
EASTERN KS INTO WEST/SOUTHWEST MO THROUGH EARLY TO MID MORNING
SHOULD LESSEN MOISTURE TRANSPORT AND THUS ABILITY TO REALIZE STEEP
LAPSE RATES ALOFT FOR MORE ROBUST ACTIVITY...AND MAYBE EVEN
THUNDER IN GENERAL NORTH OF INTERSTATE 80.
THIS AFTERNOON AND TONIGHT...
DESPITE THIS BEING IN THE FIRST 12 HOURS OF THE FORECAST...DUE TO
INFLUENCE OF MORNING STORMS AND LARGE MODEL DIFFERENCES...CONFIDENCE
ON SPECIFICS IN THESE PERIODS REMAIN LOW. THERE SHOULD BE SOME
FORM OF OUTFLOW BOUNDARY OR BOUNDARIES FROM MORNING ACTIVITY/CLOUD
COVER THAT LINGER INTO THE FORECAST AREA INTO THE AFTERNOON...MOST
FAVORED SOUTH OF INTERSTATE 80. AS WARMING AND DESTABILIZATION
OCCURS WITH DEW POINTS AROUND 70F...COULD SEE SCATTERED ACTIVITY
DEVELOP NEAR ANY SUCH BOUNDARIES DURING THE MID TO LATE AFTERNOON.
THE SECOND UPPER WAVE ACROSS WESTERN WY THIS MORNING WILL BEGIN TO
APPROACH THE REGION AS WELL BY LATE IN THE DAY...WITH FORCING FROM
THIS POSSIBLY AIDING IN SCATTERED STORM DEVELOPMENT ACROSS MUCH OF
THE REGION. EVEN EARLY THIS MORNING THERE ARE A HANDFUL OF STORMS
ACROSS THE UPPER MIDWEST NOT LINKED TO ANY SPECIFIC SURFACE
FEATURE. INCREASING DEEP LAYER SHEAR OF 35 TO 50 KT WILL SUPPORT
ISOLATED TO SCATTERED SEVERE DISCRETE STORMS IN THE REGION.
WHILE IT REMAINS DIFFICULT TO PINPOINT TIMING...IT WOULD SEEM THE
GREATEST COVERAGE IN REDEVELOPING STORMS THIS EVENING WOULD BE IN
THE SOUTHERN FORECAST AREA WHERE AFOREMENTIONED BOUNDARY MAY OCCUR
AND MODEST SOUTHWEST 850-925MB FLOW AND MOISTURE TRANSPORT
REMAINS. AS THE AREA BECOMES UNDER A RIGHT ENTRANCE REGION TO THE
UPPER JET...DO EXPECT INCREASING ASCENT TONIGHT IN THE REGION FOR
MORE ROBUST CONVECTION AND POTENTIAL SEVERE AND HEAVY RAIN
THREATS. RIGHT NOW A GUIDANCE OVERLAP WOULD INDICATE THE FAR
SOUTHEAST FORECAST AREA IS MOST FAVORED FOR THIS. PRECIPITABLE
WATERS AROUND TWO INCHES AND STORM MOTIONS NEARLY PARALLEL TO THE
UPPER AND MID LEVEL FLOW WILL PRESENT HEAVY RAIN THREATS IN
THE GENERAL CENTRAL TO SOUTHERN IL INTO IN REGIONS...BUT AGAIN AT
THIS TIME CONFIDENCE VARIES ON PLACEMENT. BECAUSE OF THAT WILL
CONTINUE WITH THE HYDROLOGIC OUTLOOK /ESF/ FOR THE AREAS HIT HARD
ON SATURDAY NIGHT WITH HEAVY RAINFALL.
TUESDAY AND WEDNESDAY...
THE FRONT SHOULD CLEAR THE FORECAST AREA SOMETIME TUESDAY MORNING.
WHILE DRY AIR ADVECTION WILL OCCUR...LIMITED CONVERGENCE REMAINS
IN THE SOUTHEAST FORECAST AREA FOR POSSIBLY A STORM OR TWO TUESDAY
BUT IT LOOKS TO BE A LOW CHANCE. TEMPERATURES ONLY COOL SLIGHTLY
AS HIGH PRESSURE QUICKLY MOVES ATOP THE AREA TUESDAY NIGHT AND
THEN EASTWARD.
WEDNESDAY NIGHT THROUGH FRIDAY...
WARM AIR ADVECTION AND A RAPID PRECIPITABLE WATER INCREASE IS
FORECAST WEDNESDAY NIGHT ON ALL GUIDANCE. FEEL THAT MODELS MAY BE
UNDER-DOING THE STORM CHANCES GIVEN FORECAST PROFILES OF STEEPENING
LAPSE RATES WITHIN A RAPIDLY MOISTENING COLUMN...AT LEAST IN THE
WESTERN FORECAST AREA. SO HAVE INCREASED POPS IN THAT AREA. AS FOR
THURSDAY...HAVE GONE DRY IN MANY AREAS COLLABORATING AND
UNDERCUTTING A MODEL BLEND OF POPS. THE SYNOPTIC PATTERN FAVORS A
HOT DAY AND BARRING ANY STRATUS ISSUES WITH WEDNESDAY NIGHTS WARM
AIR ADVECTION AND POSSIBLE PRECIP...SHOULD SEE THE 90 DEGREE MARK
REACHED OR EXCEEDED ACROSS A GOOD PART OF THE FORECAST AREA BASED
ON STRONG SOUTHWEST FLOW AND FORECAST 850MB AND 925MB TEMPERATURES
COMPARED TO CLIMATOLOGY. FOR NOW HAVE KEPT THE NORTH A LITTLE
BELOW THAT WITH THE POSSIBILITY OF MORNING CLOUDS. THE SYSTEM
COLD FRONT IS PRESENTLY FORECAST BY THE EC AND THE GFS TO COME
THROUGH THE AREA SOMETIME ON FRIDAY WHICH WOULD BRING STORM
CHANCES WITH IT...AS WELL AS FLOW TURNING OFF THE LAKE BEHIND ITS
PASSAGE.
BEYOND...
NO CHANGES MADE TO THIS WEEKEND WHERE HIGHS LOOK TO BE AROUND 70
WITH DRY CONDITIONS BEHIND THE AFOREMENTIONED FRONT. HIGH PRESSURE
AROUND 1023MB IS FORECAST BY A BLEND OF GUIDANCE. GIVEN THE 925MB
TEMPERATURES FORECAST IF THAT HIGH IS CENTERED OVER THE FORECAST
AREA SOMETIME SUNDAY OR MONDAY NIGHTS /7TH OR 8TH/...LOWS IN
OUTLYING AREAS WOULD LIKELY BE IN THE 40S.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* MVFR CIGS/VSBYS IN THE SHORT TERM WITH SHRA.
* CEILING TRENDS THROUGH THE AFTERNOON...MVFR POSSIBLE.
* WINDS GRADUALLY VEERING MORE WESTERLY THEN NORTHWEST LATE.
* VCSH AGAIN THIS EVENING...ISOLATED TSRA NOT OUT OF THE QUESTION.
LENNING
//DISCUSSION...UPDATED 12Z...
CONVECTIVE CHANCES AND TIMING CONTINUE TO BE THE PRIMARY WEATHER
CONCERN AND FOCUS FOR THE AREA TODAY.
THE OVERNIGHT THUNDERSTORM ACTIVITY TO OUR WEST HAS DISSIPATED AS
IT MOVED ACROSS NORTHERN ILLINOIS. HOWEVER...ITS EFFECTS ON THE
SURFACE WINDS AND CIGS REMAIN. AS SUCH...IT APPEARS THAT A SHORT
PERIOD OF LOW MVFR CIGS AND AN EAST-SOUTHEASTERLY WIND COMPONENT
ARE EXPECTED THROUGH AROUND 14 UTC THIS MORNING BEFORE THE WINDS
REVERT BACK OUT OF THE SOUTHWEST AND BECOME A BIT GUSTY BY MID TO
LATE MORNING.
UNCERTAINTY REMAINS SOMEWHAT HIGH IN WHETHER OR NOT ANY CONVECTIVE
ACTIVITY WILL IMPACT THE TERMINALS TODAY. OVERALL IT APPEARS THE
BEST CHANCES IN THE NEAR TERM WILL BE ROUGHLY BETWEEN 16 AND 19
UTC AS A WEATHER DISTURBANCE ACROSS NORTHEASTERN MISSOURI SHIFTS
EASTWARD OVER THE AREA. THIS COULD LEAD TO SOME DEVELOPMENT
NEAR...OR JUST SOUTH OF THE TERMINALS DURING THIS PERIOD.
THEREAFTER...IT ALSO APPEARS THERE MAY BE ANOTHER CHANCE FOR SOME
SCT STORMS THIS EVENING AFTER 23 UTC AS ANOTHER STOUT UPPER LEVEL
DISTURBANCE MOVES OVER NORTHERN ILLINOIS AS A COLD FRONT
APPROACHES. TIMING AT THIS JUNCTURE REMAINS VERY DIFFICULT TO PIN
DOWN...AND THIS WILL NEED TO BE IRONED OUT AS WE GET A BETTER
HANDEL ON TRENDS THROUGH THE DAY. EITHER WAY...THERE WILL LIKELY
BE AREAS OF CONVECTIVE ACTIVITY THIS AFTERNOON AND TONIGHT SOUTH
OF THE TERMINALS.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM TO HIGH CONFIDENCE OF BRIEF MVFR CIGS/VSBYS IN THE SHORT
TERM WITH SHRA...THEN IMPROVING.
* MEDIUM TO HIGH CONFIDENCE IN WINDS...AND HIGH CONFIDENCE THEY
REMAIN FROM A WESTERLY COMPONENT.
* MEDIUM TO LOW CONFIDENCE OF SHRA AGAIN THIS EVENING...AND LOW
CONFIDENCE REGARDING ISOLATED TSRA.
LENNING
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT THROUGH THURSDAY...PREDOMINANTLY VFR.
FRIDAY...CHANCE OF SHRA/TSRA.
SATURDAY AND SUNDAY...PREDOMINANTLY VFR.
KJB
&&
.MARINE...
232 AM CDT
IT LOOKS TO BE AN ACTIVE WEATHER DAY ACROSS THE LAKE...WITH STOUT
SOUTHERLY WINDS LAKE-WIDE...AND THE THREAT FOR SOME STRONG TO SEVERE
THUNDERSTORMS ACROSS SOUTHERN LAKE MICHIGAN. THESE STRONG SOUTHERLY
WINDS WILL RESULT IN WINDS AROUND 25 KT AND THE ONGOING SMALL CRAFT
ADVISORY STILL APPEARS GOOD. THE SURFACE LOW...RESPONSIBLE FOR THESE
STRONG SOUTHERLY WINDS TODAY...WILL SHIFT ACROSS ONTARIO...AND TO
NEAR JAMES BAY BY THIS EVENING WHILE DEEPENING TO AROUND 29.2
INCHES. AS THIS OCCURS...AN ASSOCIATED COLD FRONT WILL BE DRAWN
EASTWARD ACROSS THE LAKE BY EARLY TUESDAY MORNING. WINDS WILL BECOME
WESTERLY AND ABATE SIGNIFICANTLY WITH THE PASSAGE OF THIS FRONT.
ANOTHER PERIOD OF STRONGER SOUTHERLY WINDS LOOKS TO SET UP AGAIN
WEDNESDAY NIGHT AND THURSDAY AS ANOTHER POTENT AREA OF LOW PRESSURE
TRACKS EASTWARD ACROSS ONTARIO. WINDS SPEEDS COULD AGAIN BE AROUND
25 KT OUT OF THE SOUTH DURING THIS PERIOD. ANOTHER STRONGER COLD
FRONT LOOKS TO SHIFT DOWN THE LAKE IN THE WAKE OF THIS LOW LATE
FRIDAY AND THIS COULD SET THE STAGE FOR A DECENT NORTHERLY WIND
EVENT ACROSS THE LAKE AS A STOUT AREA OF HIGH PRESSURE QUICKLY
BUILDS EASTWARD ACROSS THE UPPER MIDWEST. STRONG NORTHERLY WINDS OF
25 TO 30 KT APPEAR QUITE POSSIBLE IN THE WAKE OF THIS COLD FRONT
FRIDAY NIGHT INTO SATURDAY...WHICH WOULD ALSO RESULT IN LARGE WAVES
IN EXCESS OF 5 FEET ACROSS SOUTHERN LAKE MICHIGAN INTO NEXT
WEEKEND.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM MONDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1001 AM CDT Mon Sep 1 2014
.UPDATE...
ISSUED AT 1001 AM CDT MON SEP 1 2014
Line of strong to severe thunderstorms tracked across Iowa last
night, then rapidly dissipated as it pushed toward the
Mississippi River early this morning. Outflow boundary from this
dying convection is currently approaching the I-55 corridor
as evidenced by westerly winds across all sites in the Illinois
River Valley. Think this outflow will eventually serve as the
primary focus for additional thunderstorm development later today.
Still some question as to exactly where the boundary will lay out
and when convection will fire, but the latest thinking from SPC
has pushed the best severe weather risk much further southeast,
generally along/south of a Danville to Jacksonville line. HRRR is
performing very poorly this morning and its solution has been
completely disregarded. Meanwhile, the 12z NAM seems to have at
least a reasonable handle on the situation, showing storms
developing by early afternoon near I-55, then shifting further
east and south later in the day. Will continue to monitor
stability parameters to see if projected 1500 to 2500J/kg CAPEs
can be realized. If the airmass destabilizes as predicted,
increasing shear values will help storms organize and potentially
produce large hail and damaging winds this afternoon into this
evening. Am still concerned about the threat for heavy rainfall
across the E/SE CWA tonight as favorable jet dynamics produce
enhanced synoptic lift along/ahead of approaching cold front. As
storms become parallel to upper flow, training appears likely
tonight along/south of a Danville to Jacksonville line. Latest NAM
continues to put down some hefty rainfall totals across this area.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 355 AM CDT MON SEP 1 2014
Shortwave trough axis approaching Illinois from the west this
morning bringing a line of thunderstorms to the region. Trends this
morning are for the line splitting into to intense lines...one
grazing Knox, Peoria, Stark county and likely Marshall and Woodford
as it continues this morning. Have reports of pea-sized hail and
wind gusts 30-40 mph with the more intense storm cells. The intense
activity looks like it will have a break through central IL in the
early morning once this initial activity shifts east-northeastward.
Isolated thunderstorms will likely develop throughout the CWA during
the morning...however daytime heating will likely be necessary to
bring CAPE values up to 1500-2500 J/KG range to bring a better
chance for severe storms when combined with 30-50 kt bulk shear
values also shifting into central Illinois. Large hail and severe
wind gusts will be a threat with the stronger storms this
afternoon...and have continued mention of severe hail and heavy rain
in forecast grids beginning at 3 pm this afternoon...continuing
through around midnight. Heavy rain will continue through the night
as a potent and moist low-level jet continues to push through the
CWA...along with lift associated with the progressive trough and
cold frontal boundary.
&&
.LONG TERM...(Tuesday through Sunday)
ISSUED AT 355 AM CDT MON SEP 1 2014
00Z models have trended slower with frontal boundary pushing into
southeast IL Tue especially the NAM model and have increase pops to
likely se of I-70 Tue morning. NAM model may be overdoing qpf
amounts Tue morning over southeast IL but models have trended higher
with qpf amounts with precipitable water values of 1.5-2 inches
from 12-15Z Tue and have increased qpf amounts to around a quarter
inch in southeast IL. IL river valley should be dry Tue and chances
of showers and thunderstorms will diminish from nw to se during
Tue afternoon. Highs 82-88F Tue and still rather humid especially
in southeast IL with dewpoints 70-75F while dewpoints lower into
mid 60s over IL river valley. Dry conditions return across area
Tue night with frontal boundary dropping south of area. Lows in
the low to mid 60s Tue night.
Models show frontal boundary starting to lift back north especially
over MS river valley and MO on Wed and have kept 20-30% chance of
showers and thunderstorms sw areas by Wed afternoon with ne areas
staying dry Wed. Warm highs in the mid to upper 80s Wed and model
guidance has trended upward in high temps Wed. Dewpoints elevate
during day Wed into upper 60s and lower 70s Wed afternoon.
Convection chances appear highest over northern IL Wed night closer
to short waves tracking into WI/northern IL and eventually eastward
into lower MI and northern IN. Have areas south of I-72 dry Wed
night.
Thu and Fri still appear to be back into the heat and humidity with
highs in the upper 80s and lower 90s and dewpoints peaking in the
low to mid 70s giving afternoon heat indices of upper 90s to lower 100s
especially Thu afternoon and in southeast IL Friday afternoon. A 593
dm 500 mb high pressure ridge over the southeast states builds the
heat into central/southeast IL late this work week. Most of our area
should be dry Thu and Thu night with just slight chance of
convection Thu afternoon mainly over the Wabash river valley and
nw of IL river Thu night. Models have trended faster with cold
front dropping se through central IL Friday and thru southeast IL
Fri evening. Have increased pops Friday and also trending cooler
with temps and dewpoints during the weekend as 1025 mb high
pressure settles into the Great Lakes region.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 708 AM CDT MON SEP 1 2014
A mix of IFR and MVFR ceilings and southerly winds generally 8-12
kts this morning across central Illinois as a cold front
approaches from the west. A line of thunderstorm activity ahead of
the front continues to approach, however activity is generally weak
along portions of the line headed for central IL. As surface
heating takes place, thunderstorm development will intensify
through the early afternoon as daytime heating initiates and the
most intense portions of the storm system move into the region.
Some storms may become severe with hail and severe wind gusts this
afternoon and evening. Thunderstorm activity will shift toward
southeast portions of the state tonight. As no clear features
exist at this point to pinpoint timing of thunderstorms, have
broad-brushed thunderstorm activity with predominant -SHRA and VCTS
in TAFs starting 16Z- 17Z...then diminished VCTS/VCSH mention from
northwest to southeast overnight. Doubtful MVFR ceilings will
dissipate significantly through the day so have kept cigs no
better than bkn020-025 for the next 24 hours.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BARNES
SHORT TERM...ONTON
LONG TERM...07
AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1247 AM CDT MON SEP 1 2014
.UPDATE...
ISSUED AT 820 PM CDT SUN AUG 31 2014
EVENING UPDATE FOR TIMING/INTENSITY OF THUNDERSTORMS INTO THE
FORECAST AREA LATE TONIGHT INTO MONDAY MORNING.
LATEST RADAR TRENDS...MODELED WELL BY THE HRRR/RAP...INDICATE
STORMS PUSHING INTO THE WESTERN FRINGE OF THE FORECAST AREA NEAR
AND AFTER 11 PM CDT. HAVE UPDATED FORECAST GRIDS TO ADJUST TIMING
AND BRING HIGHER POPS IN EARLIER. DESPITE THE COOLING BOUNDARY
LAYER...THE COMPLEX MOVING INTO CENTRAL IOWA MAY BE ABLE TO
SUSTAIN A DAMAGING WIND THREAT UNTIL 2 OR 3 AM CDT. CONVECTION
STILL EXPECTED TO WEAKEN OVERNIGHT AND DECREASE IN COVERAGE NEAR
AND EAST OF THE MISSISSIPPI RIVER. HAVE UPDATED THE HAZARDOUS
WEATHER OUTLOOK TO REFLECT FORECAST CHANGES.
&&
.SYNOPSIS...
ISSUED AT 313 PM CDT SUN AUG 31 2014
A WARM...MID SUMMER-LIKE DAY IS FOUND OVER OUR CWA TODAY AS WE
REMAIN WELL EAST OF THE COLD FRONT APPROACHING IOWA THIS AFTERNOON.
THE COLD FRONT IS SLOWLY MOVING EAST...AND HAS ALREADY SPAWNED A FEW
HIGH BASED THUNDERSTORMS FROM SOUTHERN MN TO FAR EASTERN NE.
TEMPERATURES WITH FULL SUN TODAY HAVE REACHED THE MID 80S AS OF 2
PM...AND APPEAR SET FOR HIGHS IN THE MID TO UPPER 80S BEFORE CLOUDS
INTERRUPT THE HEATING LATER THIS AFTERNOON. SURFACE BASED STORMS
REMAIN CAPPED FOR NOW...THOUGH CAPE VALUES ARE SHOWN ON RAP DATA TO BE
2000 TO 4000 J/KG.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 313 PM CDT SUN AUG 31 2014
THERE IS LITTLE DOUBT THERE WILL BE AN IMPRESSIVE CONVECTIVE EVENT
TONIGHT. THERE IS PLENTY OF DOUBT THAT IT WILL STRONGLY AFFECT MORE
THAN JUST THE WESTERN MOST PORTION OF OUR CWA. THE SLOW MOVING
FRONT SHOULD BE ENOUGH TO FOCUS STORMS WITH PLENTY OF CAPE AND
MOISTURE AVAILABLE TO THE WEST...LIKELY NEAR THE MISSOURI RIVER.
THEY SHOULD MOVE EAST...SLOWLY. THIS PLACES THE WEAKENING PHASE OF
THE COMPLEX INTO EASTERN IOWA BETWEEN MIDNIGHT AND 9 AM MONDAY. THIS
POOR DIURNAL TIMING COMBINED WITH LESS THAN IDEAL MOISTURE TRANSPORT
DURING THAT TIME FRAME SUGGESTS BOTH INTENSITY AND COVERAGE OF
STORMS WILL BE ON THE WANE IN THAT PERIOD. I HAVE CONFINED HIGH POPS
TO ONLY THE WESTERN CWA LATE TONIGHT...AND LOWERED TO CHANCE FOR
MONDAY MORNING SINCE MOST MODELS SUGGEST A FRAGMENTED LINE...AND
THAT SEEMS MOST LIKELY TO ME AS WELL. QPF SHOULD BE IMPRESSIVE TO
THE WEST...BUT MAY BE INSIGNIFICANT IN OUR CWA...GENERALLY 0.25 OR
LESS IN ALL BE THE FAR WEST...WHERE 0.5 TO 1.0 IS POSSIBLE.
MONDAY WILL SEE FAR BETTER DYNAMICS...THUS THE SPC OUTLOOK FOR
SEVERE WEATHER. HOWEVER...THE CONVERGENT OUTFLOW BOUNDARY WILL
LIKELY BE WELL IN ADVANCE OF THE COLD FRONT...WHICH SHOULD ALSO
DEFLECT THE STRONGEST HEATING WELL EAST OF THE CWA AS WELL.
THUS...THE WEAKENING CONVECTIVE DEBRIS SHOULD INHIBIT OUR MONDAY
SEVERE POTENTIAL...AS WELL AS WIDESPREAD RAIN POTENTIAL AGAIN. SURE
SEEMS THIS EVENT SHOULD PRODUCE THE MAJORITY OF ITS RAIN WEST AND
SOUTHEAST OF OUR CWA.
ERVIN
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 313 PM CDT SUN AUG 31 2014
THE FRONT WILL CLEAR THE SOUTHEAST HALF OF THE AREA LATE MONDAY
EVENING. THE SOUTHEAST HALF OF THE AREA SHOULD SEE PRECIPITATION
ONGOING AT SUNSET THAT ENDS FROM NORTHWEST TO SOUTHEAST AFTER
MIDNIGHT. DRIER AIR MOVING INTO THE AREA SHOULD RESULT IN LOWS NEAR
OR SLIGHTLY BELOW NORMAL BY SUNRISE TUESDAY.
TUESDAY/TUESDAY NIGHT DRY CONDITIONS ARE EXPECTED AS HIGH PRESSURE
MOVES THROUGH THE MIDWEST. TEMPERATURES SHOULD BE CLOSE TO NORMAL.
WEDNESDAY MORNING LOOKS TO BE DRY ACROSS THE AREA AS THE HIGH MOVES
TOWARD THE EAST COAST. A WEAK DISTURBANCE WILL MOVE THROUGH THE AREA
WEDNESDAY AFTERNOON. THE OVERALL FORCING IS NOT STRONG AND MOISTURE
AVAILABILITY IS IN QUESTION. IF PRECIPITATION DOES OCCUR IT WOULD BE
ISOLATED IN NATURE WITH THE SOUTH HALF BEING FAVORED.
WEDNESDAY NIGHT ON...
THE MODEL CONSENSUS HAS SLIGHT CHANCE TO CHANCE POPS IN EACH 12 HR
PERIOD FROM WEDNESDAY NIGHT THROUGH SATURDAY.
THERE IS A WEAK DISTURBANCE MOVING THROUGH THE AREA WEDNESDAY
NIGHT/THURSDAY. MOISTURE AVAILABILITY WILL BE ON THE INCREASE BUT
THE OVERALL FORCING IS NOT STRONG. THE POSSIBILITY DOES EXIST THERE
WILL BE PERIODS OF DRY WEATHER WEDNESDAY NIGHT/THURSDAY.
THE MODELS DIFFER SOMEWHAT ON THE TIMING BUT AGREE THAT ANOTHER COLD
FRONT WILL MOVE THROUGH THE AREA IN THE THURSDAY NIGHT THROUGH
FRIDAY NIGHT TIME FRAME.
SEVERAL MODELS ARE PUSHING A SIGNIFICANT HIGH INTO THE WESTERN GREAT
LAKES ON SATURDAY. THE CURRENT MODEL CONSENSUS HAS SLIGHT CHANCE
POPS ACROSS THE SOUTH QUARTER OF THE AREA BUT THE OVERALL TREND IS
SUGGESTING DECREASING PRECIPITATION CHANCES.
SATURDAY NIGHT THROUGH SUNDAY THE MODEL CONSENSUS HAS DRY CONDITIONS
WITH HIGH PRESSURE OVER THE GREAT LAKES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1237 AM CDT MON SEP 1 2014
LINEAR MESOSCALE CONVECTIVE SYSTEM WILL CONTINUE TO MOVE ACROSS THE
REGION OVERNIGHT WHILE SLOWLY WEAKENING. GUSTY WINDS WITH MVFR TO
LOCALLY IFR CONDITIONS EXPECTED IN THE STORMS... WITH AN ISOLATED
SEVERE WIND GUST TO 60 MPH POSSIBLE NEAR TO SOUTHWEST OF QUAD CITIES.
WAKE LOW FOLLOWING MAY RESULT IN GUSTY EAST/SOUTHEAST WINDS DEVELOPING
INTO EASTERN IA ESPECIALLY AT KCID TERMINAL. COLD FRONT ANTICIPATED
TO PASS THROUGH THE TERMINALS THIS AFTERNOON. REDEVELOPMENT OF SOME
SHOWERS AND STORMS IS POSSIBLE AHEAD OF THE FRONT FAVORING KMLI AND
KBRL...BUT NOT CONFIDENT TO INTRODUCE AT THIS TIME DUE TO POSSIBLE
LINGERING DEBRIS CLOUDS FROM AM CONVECTION AND WEAK FRONTAL CONVERGENCE.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...RP KINNEY
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...08
AVIATION...05
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
622 PM CDT TUE SEP 2 2014
...UPDATE TO AVIATION...
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 344 PM CDT TUE SEP 2 2014
THE MID TO UPPER LEVEL FLOW HAS BECOME ZONAL IN THE WAKE OF THE
MINOR SHORTWAVE TROUGH THAT TRAVERSED THE CENTRAL PLAINS MONDAY
EVENING. THE EFFECTIVE FRONTAL BOUNDARY AFTER ALL OF THE NIGHTTIME
CONVECTION WAS SITUATED ACROSS CENTRAL OKLAHOMA AND SOUTHERN
ARKANSAS. SOUTH OF THIS FRONT, TEMPERATURES WERE ABOVE 90 AS OF 2
PM, BUT ON THE COOL SIDE OF THE FRONT, MOST READINGS WERE IN THE
70S TO LOWER 80S. LEE TROUGHING WILL DEVELOP TONIGHT AND
WEDNESDAY IN RESPONSE TO THE ZONAL FLOW. LATE TONIGHT, WARMER MID
LEVEL TEMPERATURES WILL SPREAD ACROSS SOUTHWEST KANSAS, CAPPING
THE ELEVATED MOIST LAYER. THE NAM INDICATES THAT LOW LEVEL WINDS
WILL BECOME SOUTHERLY AS THE WARM FRONT SHIFTS INTO NORTHERN
KANSAS BY WEDNESDAY MORNING. HOWEVER, THE RAP SHOWS THE BOUNDARY
STILL SITUATED ALONG THE KANSAS/OKLAHOMA BORDER AT 12Z. SINCE WE
MAY MAINTAIN UPSLOPE SOUTHEASTERLY FLOW MOST OF THE NIGHT, I OPTED
TO BRING THE LOW CLOUDS AND FOG BACK IN TOWARD 09Z. A MID LEVEL
CLOUD DECK MAY DEVELOP AS THE LOW LEVEL JET DEVELOPS THIS EVENING
AND AN ELEVATED THUNDERSTORM OR TWO CAN`T BE COMPLETELY RULED OUT
OVER SOUTH CENTRAL KANSAS BEFORE THE STRONG CAPPING INVERSION
DEVELOPS.
ON WEDNESDAY, THE LEE TROUGH WILL BECOME ESTABLISHED ACROSS THE
HIGH PLAINS, WITH A WEAK SURFACE DRYLINE SITUATED ACROSS FAR
WESTERN KANSAS. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT
LATE IN THE DAY. HIGH TEMPERATURES WILL BE IN THE MID TO HIGH 90S,WITH
SOME READINGS CLOSE TO 100F.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 357 PM CDT TUE SEP 2 2014
A STRONG UPPER LEVEL SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST
WILL MOVE EASTWARD INTO THE NORTHERN PLAINS AND UPPER MIDWEST BY
FRIDAY. THIS SYSTEM WILL PUSH A COLD FRONT ACROSS WESTERN KANSAS AND
THE CENTRAL PLAINS ON THURSDAY BRINGING THE BEST CHANCES FOR SHOWERS
AND THUNDERSTORMS. THE STRONGEST MID AND UPPER LEVEL WINDS WILL BE
IN NEBRASKA, SO NOT EXPECTING LOTS OF SEVERE WITH THE FRONT. CAPE
VALUES AROUND 2000 J/KG WILL BE SUFFICIENT TO PRODUCE SOME SMALL
HAIL AND STRONG WINDS AS THE COLD FRONT SWEEPS ACROSS WESTERN KANSAS
TO NEAR DODGE CITY BY 7 PM THURSDAY AND THROUGH MEDICINE LODGE BY
AROUND MIDNIGHT.
HIGH TEMPERATURES WILL BE VERY WARM AHEAD OF THE COLD FRONT ON
THURSDAY WITH LOW TO MID AND UPPER 90S FORECAST. HIGHS THEN COOL
INTO THE 70S INTO FRIDAY WITH A CONTINUED CHANCE FOR MAINLY
AFTERNOON THUNDERSTORMS BEHIND THE FRONT IN MOIST SURFACE UPSLOPE
FLOW.
BY MONDAY HIGHS WARM BACK INTO THE 80S AS THE COOL HIGH PRESSURE
AREA MOVES EAST AND WARM SOUTHERLY WINDS INCREASE. MORE THUNDERSTORM
CHANCES CONTINUE INTO TUESDAY WITH DISTURBANCES IN SOUTHWEST FLOW
ALOFT AND UPPER JET.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 618 PM CDT TUE SEP 2 2014
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH LATE THIS
EVENING. AREAS OF LOW LEVEL STRATUS ARE EXPECTED TO DEVELOP ACROSS
PORTIONS OF CENTRAL AND SOUTHWEST KANSAS LATE TONIGHT AS A RESULT
OF HIGH RELATIVE HUMDITY AND LIGHT SOUTHEAST UPSLOPE WINDS. IFR
CIGS WILL BE POSSIBLE IN THE VICINITY OF ALL TAF SITES OVERNIGHT.
THE POTENTIAL FOR FOG EXISTS AS WELL TOWARD DAYBREAK WEDNESDAY
MORNING RESULTING IN POTENTIAL MVFR VSBYS IN THE VICINITY OF ALL
TAF SITES. VFR CONDITIONS WILL RETURN BY MID DAY WEDNESDAY.
SOUTHEASTERLY WINDS OF AROUND 5 TO 15KT TONIGHT WILL BECOME MORE
SOUTHERLY LATE WEDNESDAY MORNING WHILE INCREASING TO AROUND 20 TO
30KT AS A LEE SIDE TROUGH STRENGTHENS ACROSS EASTERN COLORADO.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 70 97 72 95 / 10 0 10 30
GCK 68 99 70 92 / 0 0 10 40
EHA 66 99 68 94 / 0 10 10 30
LBL 70 98 71 96 / 0 0 10 20
HYS 68 98 72 92 / 10 10 10 50
P28 72 97 74 97 / 30 10 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...KRUSE
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS TOPEKA KS
319 PM CDT Mon Sep 1 2014
.SHORT TERM...(This Evening through Tuesday)
Issued at 319 PM CDT MON SEP 1 2014
Quick cyclonic upper flow remains in place with the core of last
night`s wave already in the Great Lakes and another weaker wave
coming into the High Plains per recent water vapor imagery. The cold
front`s location is hard to nail down behind outflow from the
overnight convection and weak pressure fields, but appears to be
bisecting the local area from southwest to northeast. Lower cloud
under a modest inversion has been rather prevalent today, keeping
temps in the 70s.
Modest convergence persists in east central Kansas this afternoon.
With still some CIN remaining per RAP analysis, confirmed by recent
visible satellite imagery, and the western upper wave staying well
north, storm chances don`t look great, but will maintain some
mention ahead of the front in east central Kansas, diminishing with
time as weak high pressure continues to move across northern sections
of the state. There are some breaks in the clouds to the south, and
some increase in instability is anticipated for the next few hours.
Deep layer is not very high in the weak low level wind fields, but
hard to completely rule out with mixed layer CAPE likely rising to
near 1500 J/kg. As the surface high builds in, winds should be
rather light, and depending on cloud trends particularly with
convection, a fairly good setup for radiational fog will be in place
with cloudy skies and limited mixing today and low cloud scouring
out following the recent heavy rain. Will go ahead with some patchy
fog mention at this point and let later shifts watch trends. Storm
chances continue to look like Tuesday but with the boundary again
possibly not far south, will keep a small chance near it. Better
mixing and insolation should yield highs back into the 80s.
.LONG TERM...(Tuesday Night through Monday)
Issued at 319 PM CDT MON SEP 1 2014
Models continue to show the potential for elevated thunderstorms
and large hail Tuesday night. The one wrinkle is the NAM appears to
be quite a bit stronger in magnitude for both the elevated
instability and effective shear. There is still good theta-e
advection along the nose of the low level jet as well as
isentropic upglide, so I think there should be some storms over
eastern KS. The question is whether they will be strong enough to
produce severe hail. Have continued with a chance POP through the
night and think the potential still exists for some severe storms.
It just may be more marginal than the NAM would suggest.
With the exception of some elevated precip possibly lingering
through the morning Wednesday, the forecast should quiet down as
the models keep the jet stream and synoptic scale energy north of
the forecast through Thursday morning. By Thursday night, a frontal
system is projected to begin moving into the area. There is some
uncertainty in the timing of the frontal system as most solutions
have trended faster with the front, the NAM being the fastest. For
now I`ve not made many changes from the previous forecast thinking
the front would move through mainly Friday and Friday evening with
the higher chances for precip in these periods. However if the
faster trend continues, the POPs may need to be pushed up in the
forecast as well. Have continued to trend POPs down for Saturday
and kept a dry forecast for Sunday with models showing surface
ridging and relatively dryer air over KS. By Monday, there is some
disagreement with the GFS and ECMWF in the amplification of an
upper trough across the west. Because the GFS is the more
amplified solution, it is quick to set up return flow with the
potential for shortwaves within southwesterly flow aloft to pass
near the area. Have taken a conservative approach with the
forecast at this time and have introduced only a slight chance for
precip on Monday until there is a little more agreement in
solutions.
Temps will remain quite warm Wednesday and Thursday as the models
show the thermal ridge over portions of the state. Because of this
have continued with highs in the 90s and lows from around 70 to
the mid 70s. Cold air advection is expected to increase Thursday
night as the front moves through the area. This should bring a
cool down for the weekend with highs in the 70s and lows in the
50s to around 60.
&&
.AVIATION...(For the 18Z TAFs through 18Z Tuesday Afternoon)
Issued at 1251 PM CDT MON SEP 1 2014
Appears convective concerns at TOP and FOE are somewhat lower than
earlier expectations with persistent cloud keeping instability in
check and area of convergence near passing boundary should be
south before instability develops. Flow behind the boundary should
clear skies somewhat allowing for decent radiational fog setup
around 11Z. Have introduced MVFR BR at this point.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...65
LONG TERM...Wolters
AVIATION...65
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1241 AM CDT Mon Sep 1 2014
.MESOSCALE DISCUSSION...
Issued at 1240 AM CDT MON SEP 1 2014
The midnight through 3 AM period will continue to see at least some
low end potential for marginally severe hail, and perhaps localized
damaging wind gusts in the strongest storms able to downburst and
transport momentum to the surface through the inversion (refer to
recent SPC mesoscale discussion for more details).
Aside from severe potential, the potential for flash flooding is
increasing and could see additional warnings needed during the
overnight hours. The outflow from the complex of storms has pushed
into southern Kansas and stretched west-to-east while the upper
trough and overall storm motion remains east southeast nearly
parallel to the effective boundary. Moisture transport is very
impressive into and over the frontal zone into central and east
central Kansas while precipitable water values are running 2 to 2.2
inches according to RAP analysis. Dual-pol signatures have at times
indicated very heavy rainfall rates to around 2" per hour with the
heaviest activity and spotters have reported 15-20 minute periods
with 1 to 1.5 inches of rain. The orientation of the front and storm
motion suggests training of individual convective updrafts over the
same areas from southern Dickinson through Morris, Lyon, Coffey,
Anderson, southern Osage and southern Franklin counties. Dual-pol
rain estimates as of midnight range from 4" in southern Dickinson
county to 2.5" in Lyon county to 2" in Osage/Franklin counties.
Given current trends and expectations, could end up seeing a broad
swatch of 2 to 5" with locally 6+ inches possible.
There are some indications that the rear edge of the convection is
beginning to forward propagate toward the southeast which may help
put a slightly faster end to the very heavy rain, but should
continue to see development in advance of the upper trough axis and
north of the outflow which could persist even behind any forward
propagating segments. This heavy precip is also falling across the
parts of the area that have been driest as of late, and can handle
more water. However, the torrential rates alone will produce
substantial runoff and may be sufficient for flash flooding even in
the dry conditions.
&&
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Monday)
Issued at 311 PM CDT SUN AUG 31 2014
Elevated activity has weakened and exited with good insolation in
recent hours in weak subsidence allowing for a quick increase in
winds and temps. 19Z surface observations suggest cold front from
south central Nebraska to the SW corner of Kansas with some CU
development on the north end. Recent water vapor imagery shows
main upper wave pushing through southern Wyoming with convection
in NC Colorado well behind the front.
Overall setup continues to support a rather wet next 12-18 hours
with cold front coming into northern and western areas overnight and
upper trough following, with low level jet ramping up to around
60kts. Nearby 12Z observed precipitable water values were at to just
above normal and continued advection of deeper moisture to the south
will pump these values up.
Still having some question on the early hours of the event. With
surface low pressure in far SE Colorado, convergence along the front
is not great, and the main upper trough well behind will not boost
convergence until perhaps the daytime hours of Labor Day. Various
higher resolution models are delayed with the convective initiation
until around 23-0Z and could occur well into the CWA. Dewpoint
depressions should remain in the 25-40F range for somewhat high
cloud bases, but increasing low level wind fields will support
strong low level helicity. Again, with the trough lagging, mid level
winds are somewhat low to support a long-lived supercell, and wind
and hail continue to the be the main severe weather concerns with ML
CAPE of 2000-2500 J/kg and downdraft CAPE around 1200 J/kg currently
analyzed. The high-res models are also similar with a secondary
impulse of convection moving through in the late evening to
overnight hours, perhaps via a sustained MCS from the current NC
Colorado storms. This could track over northern areas again and
bring an increased flooding concern, but with recent rains spotty at
best, am not confident enough for a Watch. Convection should overall
slowly clear from northwest to central areas overnight.
Cold front still appears to sag south into southern areas for the
afternoon hours of Labor Day. This again is not a clear-cut forecast
with convective activity possibly affecting the location of the
effective front. If at least some insolation can occur, cooling mid
levels behind the upper trough should allow for moderate instability
to again develop along and ahead of the effective front with plenty
of shear to support severe storms. This time, upper winds will be
stronger but weaker near the surface.
.LONG TERM...(Monday Night through Sunday)
Issued at 311 PM CDT SUN AUG 31 2014
For Monday night and Tuesday, have continued chances for precip as
the expected outflow boundary from tonight`s convection gets hung
up across southeast and south central KS. In general would anticipate
POPs diminishing and becoming increasingly confined to far
southern portions of the forecast area with time through the day
Tuesday as the upper forcing moves east of the area and the low
level jet veers to the southwest decreasing convergence along the
front.
Tuesday night may be more interesting in terms of strong to
possibly severe thunderstorms. Most model guidance is pointing to
strong theta-e advection overnight with good isentropic upglide.
Additionally model forecast soundings have fairly steep mid level
lapse rates with potentially 1000 to 1500 J/km of elevated
instability. The NAM also shows around 30 KTS of effective bulk
shear, so it is not out of the question that there could be some
elevated storms capable of producing large hail. This activity may
linger into Wednesday morning. After that the forecast is
expecting a dry period through Thursday before models bring a
frontal system into the area Thursday night through Friday night.
Because of this boundary, have continued with some chance POPs for
Thursday night through Friday. By Saturday, both the GFS and ECMWF
build a surface ridge into the central plains with dryer air
advecting in. Because of this, have trended POPs down for Saturday
and kept Sunday dry.
Temps are expected to remain warm through Thursday until the
frontal system enters the region with chances for rain. The
warmest days look to be Wednesday and Thursday as 850 temps warm
to around 25C. Therefore have highs in the mid 90s with lows
around 70 to the lower 70s. Temps should trend cooler by the
weekend due to cold air advection behind the front. May see lows
in the 50s with highs in the upper 70s to around 80 by Sunday.
&&
.AVIATION...(For the 06Z TAFs through 06Z Monday Night)
Issued at 1240 AM CDT MON SEP 1 2014
For the 06z TAFs, widespread showers and embedded thunderstorms will
persist through the overnight hours into Monday morning. Some models
are suggesting that areas of fog may develop before sunrise,
especially near KTOP/KFOE. There is still uncertainty with regards
to whether or not this will occur as winds may stay just high enough
to diminish this threat, but went ahead and added a TEMPO group at
this time and will continue to monitor the trends through the
overnight hours. Expect this precipitation to shift south of the TAF
sites during the morning hours with winds veering to the northwest
and eventually north-northeast with the frontal passage. There is a
chance for additional scattered thunderstorm develop late afternoon
into early evening. However, the TAF sites may be near the northern
edge of this precipitation development, so have only mentioned VCTS
at this time due to the uncertainty in the exact location of these
storms. Any storms that do develop near the TAF sites should shift
southward by mid to late evening.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE...Barjenbruch
SHORT TERM...65
LONG TERM...Wolters
AVIATION...Hennecke
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1020 PM EDT TUE SEP 2 2014
.UPDATE...
ISSUED AT 1020 PM EDT TUE SEP 2 2014
01Z SFC ANALYSIS SHOWS WAKE HIGH PRESSURE OVER MUCH OF EAST KENTUCKY
TRAILING THE LINEAR MCS THAT PASSED THROUGH DURING THE EVENING WITH
STRONG TO SEVERE STORMS THAT PRODUCED MAINLY DAMAGING WIND GUSTS.
THIS SYSTEM HAS ESSENTIALLY WASHED OUT THE FRONT AND PUSHED IT MAINLY
SOUTH AND EAST OF KENTUCKY. HOWEVER...THERE WILL STILL BE SOME
SCATTERED SHOWERS AND PERHAPS A STRAY STORM AROUND THE FAR SOUTHEAST
PORTION OF THE CWA INTO THE NIGHT. THE CLOUDS WILL GRADUALLY THIN AND
CLEAR OVERNIGHT AND THIS WILL LIKELY SET THE STAGE FOR FOG
FORMATION...BECOMING LOCALLY DENSE IN THE VALLEYS BY DAWN. HAVE
INCLUDED THIS ALL IN THE GRIDS WITH THIS UPDATE. ALSO FINE TUNED THE
TEMPS AND DEWPOINTS THROUGH MORNING PER THE LATEST OBS...TRENDS...AND
GUIDANCE FROM THE CONSSHORT. THESE HAVE BEEN SENT TO THE NDFD AND WEB
SERVERS. A FRESHENED SET OF ZONES AND HWO HAVE BEEN SENT.
UPDATE ISSUED AT 758 PM EDT TUE SEP 2 2014
THE MAIN LINE OF STORMS IS FINALLY MOVING INTO THE NEIGHBORING
STATES. A SECONDARY TROUGH IS MOVING THROUGH THE BLUEGRASS AND
APPEARS TO BE FALLING APART. THIS SYSTEM WILL CONTINUE TO MOVE TO THE
SOUTH AND EAST AND WILL BE OUT OF THE AREA BY MORNING. HAD TO LOWER
THE TEMPERATURES AS THEY DROPPED DOWN MUCH LOWER THAN EXPECTED AS THE
LINE WENT THROUGH THE AREA. EXPECT FOG TO BE FORMING AS THE SYSTEM
MOVES OUT. IT WILL BE PATCHY...BUT MAINLY DENSE. SOME ISOLATED
SHOWERS MAY DEVELOP BEHIND THE MAIN SYSTEM TONIGHT...SO DID NOT
IMMEDIATELY END THE PRECIPITATION CHANCES. THE REST OF THE FORECAST
IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 343 PM EDT TUE SEP 2 2014
A LINE OF THUNDERSTORMS WITH HEAVY RAINS HAS FORMED ALONG AN OLD
OUTFLOW BOUNDARY ACROSS THE MID SECTION OF EASTERN KENTUCKY. SOME OF
THE STORMS HAVE BECOME NEAR SEVERE AND EXPECT SOME SEVERE STORM
WARNINGS TO BE ISSUED DURING THE NEXT FEW HOURS. THE MAIN THREAT
WILL BE WIND GUSTS. ANOTHER CONCERN IS THAT WITH UNIDIRECTIONAL FLOW
AND HIGH PRECIPITABLE WATER...FLOODING CONCERNS WILL BE A REAL ISSUE
THIS AFTERNOON AND EVENING...MAINLY IN THE SOUTHERN HALF OF EASTERN
KENTUCKY AND ESPECIALLY ALONG THE OLD OUTFLOW BOUNDARY. EXPECT THE
FRONT TO PUSH THE PRECIPITATION SOUTH OF THE AREA BY WEDNESDAY
MORNING. IN GENERAL...THE HRRR AND RAP HAVE NOT BEEN DOING TOO WELL
WITH THIS SYSTEM SO FAR. WEDNESDAY FIGURES TO BE A LITTLE MORE
COMFORTABLE AS THE HUMIDITY WILL BE A LITTLE LOWER.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 301 PM EDT TUE SEP 2 2014
THE MODELS BEGIN THE EXTENDED PERIOD IN PRETTY GOOD AGREEMENT ONCE
AGAIN...WITH A RIDGE OF HIGH PRESSURE...BOTH ALOFT AND AT THE
SURFACE...CENTERED OVER THE EASTERN GULF OF MEXICO...ALONG WITH A
WELL DEFINED TROUGH OF LOW PRESSURE ALOFT TAKING SHAPE OVER THE
NORTHERN PLAINS. THE MODELS HAVE THE RIDGE STEADILY BREAKING DOWN
TO BEGIN THE PERIOD...WITH SHOWERS AND STORMS POPPING UP BENEATH IT
ACROSS THE TENNESSEE VALLEY DOWN TO THE GULF AND ACROSS PORTIONS OF
THE SOUTHEASTERN CONUS. AS THE TROUGH EVOLVES AND STRENGTHENS...IT
WILL EJECT OUT OF THE PLAINS WEDNESDAY AND THURSDAY...AND PUSH
ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS. THE COLD FRONT
TRAILING FROM THIS UPPER LOW WILL END UP BEING OUR WEATHER MAKER FOR
THE UPCOMING WEEKEND. THE FRONT IS EXPECTED TO INTERACT WITH
MOISTURE COMING OFF THE GULF OF MEXICO ON SOUTHWESTERLY WINDS. THE
FRONT WILL HAVE A DIFFICULT TIME MOVING EASTWARD...HOWEVER...AS THE
RIDGE DIGS IN A BIT JUST OFF THE SOUTHEAST COAST AND FLOW ALOFT
BECOMES MORE ZONAL. THERE WILL BE A GOOD CHANCE OF RAIN FRIDAY
MORNING THROUGH SUNDAY MORNING...AS LIFT AND MOISTURE ALONG THE
SLUGGISH FRONT SET OFF REPEATED ROUNDS OF SHOWERS AND STORMS. THE
RAIN SHOULD FINALLY MOVE OUT OF THE AREA SUNDAY EVENING...AS THE
FRONT FINALLY MOVES OUT OF THE AREA.
TEMPERATURES TO BEGIN THE PERIOD LOOK TO BE ABOVE NORMAL...WITH
HIGHS TOPPING OUT AROUND IN THE MID TO UPPER 80S THURSDAY AND
FRIDAY. ONCE THE FRONT STALLS ACROSS THE AREA AND PRECIPITATION
BECOMES MORE WIDESPREAD...TEMPERATURES WILL LIKELY MAX OUT BELOW
NORMAL VALUES SATURDAY THROUGH MONDAY. THE POSITIONING OF THE FRONT
OVER THE WEEKEND WILL ALLOW FOR SOME COOLER AND DRIER AIR TO FILTER
INTO THE AREA. HIGHS ON SATURDAY SHOULD BE JUST BELOW NORMAL...AS
THE BULK OF COOL AIR SHOULD STILL BE TRAPPED NORTH OF THE OHIO
RIVER. ON SUNDAY...HOWEVER...ONCE WINDS HAVE SHIFTED TO THE
NORTH...TEMPERATURES WILL BE QUITE COOL...WITH READINGS PEAKING IN
THE MID TO UPPER 70S FOR MOST LOCATIONS. THE NORTHERLY FLOW WILL
ONLY ALLOW FOR A SMALL WARM UP ON MONDAY...AS HIGHS THAT DAY WILL
LIKELY ONLY TOP OUT IN THE UPPER 70S AND LOWER 80S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 758 PM EDT TUE SEP 2 2014
THE THUNDERSTORMS HAVE MOVED OUT OF EASTERN KENTUCKY. SOME SHOWERS
WILL BE POSSIBLE FOR A WHILE BEHIND THE SYSTEM. AS SOME CLEARING
OCCURS...EXPECT SOME DENSE FOG TO FORM. THE FOG SHOULD BE DENSE AND
EVENTUALLY BRING ALL THE TAF STATIONS TO VLIFR. EXPECT A RETURN TO
VFR AFTER 14Z. FROM 00 TO 04Z...THE FOG MAY MOVE IN AND OUT OF
AREAS...ESPECIALLY AT JKL AS SOME STRATUS MOVES OUT OF THE VALLEY AND
MOVES ACROSS THE VSBY SENSOR.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...JJ
LONG TERM...AR
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
759 PM EDT TUE SEP 2 2014
.UPDATE...
ISSUED AT 758 PM EDT TUE SEP 2 2014
THE MAIN LINE OF STORMS IS FINALLY MOVING INTO THE NEIGHBORING
STATES. A SECONDARY TROUGH IS MOVING THROUGH THE BLUEGRASS AND
APPEARS TO BE FALLING APART. THIS SYSTEM WILL CONTINUE TO MOVE TO THE
SOUTH AND EAST AND WILL BE OUT OF THE AREA BY MORNING. HAD TO LOWER
THE TEMPERATURES AS THEY DROPPED DOWN MUCH LOWER THAN EXPECTED AS THE
LINE WENT THROUGH THE AREA. EXPECT FOG TO BE FORMING AS THE SYSTEM
MOVES OUT. IT WILL BE PATCHY...BUT MAINLY DENSE. SOME ISOLATED
SHOWERS MAY DEVELOP BEHIND THE MAIN SYSTEM TONIGHT...SO DID NOT
IMMEDIATELY END THE PRECIPITATION CHANCES. THE REST OF THE FORECAST
IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 343 PM EDT TUE SEP 2 2014
A LINE OF THUNDERSTORMS WITH HEAVY RAINS HAS FORMED ALONG AN OLD
OUTFLOW BOUNDARY ACROSS THE MID SECTION OF EASTERN KENTUCKY. SOME OF
THE STORMS HAVE BECOME NEAR SEVERE AND EXPECT SOME SEVERE STORM
WARNINGS TO BE ISSUED DURING THE NEXT FEW HOURS. THE MAIN THREAT
WILL BE WIND GUSTS. ANOTHER CONCERN IS THAT WITH UNIDIRECTIONAL FLOW
AND HIGH PRECIPITABLE WATER...FLOODING CONCERNS WILL BE A REAL ISSUE
THIS AFTERNOON AND EVENING...MAINLY IN THE SOUTHERN HALF OF EASTERN
KENTUCKY AND ESPECIALLY ALONG THE OLD OUTFLOW BOUNDARY. EXPECT THE
FRONT TO PUSH THE PRECIPITATION SOUTH OF THE AREA BY WEDNESDAY
MORNING. IN GENERAL...THE HRRR AND RAP HAVE NOT BEEN DOING TOO WELL
WITH THIS SYSTEM SO FAR. WEDNESDAY FIGURES TO BE A LITTLE MORE
COMFORTABLE AS THE HUMIDITY WILL BE A LITTLE LOWER.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 301 PM EDT TUE SEP 2 2014
THE MODELS BEGIN THE EXTENDED PERIOD IN PRETTY GOOD AGREEMENT ONCE
AGAIN...WITH A RIDGE OF HIGH PRESSURE...BOTH ALOFT AND AT THE
SURFACE...CENTERED OVER THE EASTERN GULF OF MEXICO...ALONG WITH A
WELL DEFINED TROUGH OF LOW PRESSURE ALOFT TAKING SHAPE OVER THE
NORTHERN PLAINS. THE MODELS HAVE THE RIDGE STEADILY BREAKING DOWN
TO BEGIN THE PERIOD...WITH SHOWERS AND STORMS POPPING UP BENEATH IT
ACROSS THE TENNESSEE VALLEY DOWN TO THE GULF AND ACROSS PORTIONS OF
THE SOUTHEASTERN CONUS. AS THE TROUGH EVOLVES AND STRENGTHENS...IT
WILL EJECT OUT OF THE PLAINS WEDNESDAY AND THURSDAY...AND PUSH
ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS. THE COLD FRONT
TRAILING FROM THIS UPPER LOW WILL END UP BEING OUR WEATHER MAKER FOR
THE UPCOMING WEEKEND. THE FRONT IS EXPECTED TO INTERACT WITH
MOISTURE COMING OFF THE GULF OF MEXICO ON SOUTHWESTERLY WINDS. THE
FRONT WILL HAVE A DIFFICULT TIME MOVING EASTWARD...HOWEVER...AS THE
RIDGE DIGS IN A BIT JUST OFF THE SOUTHEAST COAST AND FLOW ALOFT
BECOMES MORE ZONAL. THERE WILL BE A GOOD CHANCE OF RAIN FRIDAY
MORNING THROUGH SUNDAY MORNING...AS LIFT AND MOISTURE ALONG THE
SLUGGISH FRONT SET OFF REPEATED ROUNDS OF SHOWERS AND STORMS. THE
RAIN SHOULD FINALLY MOVE OUT OF THE AREA SUNDAY EVENING...AS THE
FRONT FINALLY MOVES OUT OF THE AREA.
TEMPERATURES TO BEGIN THE PERIOD LOOK TO BE ABOVE NORMAL...WITH
HIGHS TOPPING OUT AROUND IN THE MID TO UPPER 80S THURSDAY AND
FRIDAY. ONCE THE FRONT STALLS ACROSS THE AREA AND PRECIPITATION
BECOMES MORE WIDESPREAD...TEMPERATURES WILL LIKELY MAX OUT BELOW
NORMAL VALUES SATURDAY THROUGH MONDAY. THE POSITIONING OF THE FRONT
OVER THE WEEKEND WILL ALLOW FOR SOME COOLER AND DRIER AIR TO FILTER
INTO THE AREA. HIGHS ON SATURDAY SHOULD BE JUST BELOW NORMAL...AS
THE BULK OF COOL AIR SHOULD STILL BE TRAPPED NORTH OF THE OHIO
RIVER. ON SUNDAY...HOWEVER...ONCE WINDS HAVE SHIFTED TO THE
NORTH...TEMPERATURES WILL BE QUITE COOL...WITH READINGS PEAKING IN
THE MID TO UPPER 70S FOR MOST LOCATIONS. THE NORTHERLY FLOW WILL
ONLY ALLOW FOR A SMALL WARM UP ON MONDAY...AS HIGHS THAT DAY WILL
LIKELY ONLY TOP OUT IN THE UPPER 70S AND LOWER 80S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 758 PM EDT TUE SEP 2 2014
THE THUNDERSTORMS HAVE MOVED OUT OF EASTERN KENTUCKY. SOME SHOWERS
WILL BE POSSIBLE FOR A WHILE BEHIND THE SYSTEM. AS SOME CLEARING
OCCURS...EXPECT SOME DENSE FOG TO FORM. THE FOG SHOULD BE DENSE AND
EVENTUALLY BRING ALL THE TAF STATIONS TO VLIFR. EXPECT A RETURN TO
VFR AFTER 14Z. FROM 00 TO 04Z...THE FOG MAY MOVE IN AND OUT OF
AREAS...ESPECIALLY AT JKL AS SOME STRATUS MOVES OUT OF THE VALLEY AND
MOVES ACROSS THE VSBY SENSOR.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...JJ
LONG TERM...AR
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
155 PM EDT MON SEP 1 2014
.UPDATE...
ISSUED AT 155 PM EDT MON SEP 1 2014
UPDATED THE FORECAST TO BETTER TIME A LINE OF SCATTERED SHOWERS AND
THUNDERSTORMS MOVING IN FROM THE WEST. THIS LINE IS OUT AHEAD OF THE
COLD FRONT IN THE WARM AIR. THERE IS A BIT OF CURVATURE TO THE LINE
OF HEAVIEST STORMS;...SO WILL BE WATCHING FOR SOME POTENTIALLY STRONG
WIND GUSTS AS THE LINE GOES THROUGH. THE MERCER AND LINCOLN COUNTY
MESONET SITES SAW WIND GUSTS OF 30 MPH AS THE LINE WENT THROUGH.
CURRENT THINKING IS THE MAX GUSTS WILL STAY BELOW 40 MPH AND WILL BE
IN THE 20 TO 30 MPH RANGE AS THE STORMS MOVE INTO EASTERN KENTUCKY.
THE HEATING WILL BE A LITTLE BETTER...HOWEVER THE STORMS SEEM TO BE
WEAKENING A LITTLE BIT. SO FAR...HAVE ONLY BEEN SEEING UP TO ONE
QUARTER OF AN INCH OF RAIN FROM THE STORMS. HAVE A LITTLE CONCERN FOR
PARTS OF EASTERN KENTUCKY THAT GOT HAMMERED LAST NIGHT FROM THE HEAVY
RAIN...HOWEVER THESE STORMS HAVE BEEN QUITE PROGRESSIVE AND HAVE NOT
YET SEEN ANY TRAINING OF THE ECHOES.
UPDATE ISSUED AT 1048 AM EDT MON SEP 1 2014
UPDATED THE FORECAST TO INCLUDE ALL OF EASTERN KENTUCKY IN THE CHANCE
OF PRECIPITATION TODAY BASED ON THE HIGH HRRR AND RUC MODEL OUTPUT AS
WELL AS THE CURRENT RADAR. BASED ON THE NAM BUFFER SOUNDINGS...DO
HAVE SOME CONCERN THAT SOME OF THE STORMS TODAY COULD PRODUCE
STRONG...BUT SUB SEVERE...WIND GUSTS TODAY. THERE IS SUFFICIENT
INSTABILITY AND SOME DRY AIR ALOFT THAT WOULD MAKE THIS FAVORABLE.
STILL HAVE CONCERN FOR SOME STRONG STORMS FOR TUESDAY AFTERNOON AND
EVENING AS WELL. WOULD NOT BE TOO SURPRISED TO SEE EASTERN KENTUCKY IN
AN SPC SLIGHT RISK BOX FOR TOMORROW. THE REST OF THE FORECAST IS ON TRACK.
UPDATE ISSUED AT 647 AM EDT MON SEP 1 2014
CLOUD COVER HAS EXPANDED A BIT FROM EARLIER...SO HAVE ADJUSTED THE
SKY COVER TO REFLECT CLOUDIER SKIES THROUGH DAYBREAK. ALSO ADJUSTED
TEMPERATURES UP A FEW DEGREES ACROSS THE BOARD AS THE CLOUDS ARE
HOLDING TEMPERATURES UP MAINLY IN THE LOW 70S. HRRR CONTINUES TO
PAINT OUT SOME ISOLATED TO SCATTERED SHOWERS AND STORMS THIS
AFTERNOON...AND THE 06Z NAM HAS ALSO NOW SUPPORTING A FEW SHOWERS AND
STORMS. THUS IT DOES LOOK LIKE SOME ACTIVITY CAN BE EXPECTED BY THE
AFTERNOON HOURS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 331 AM EDT MON SEP 1 2014
ZONAL FLOW RESIDES ACROSS KENTUCKY THIS MORNING...WITH A SHORTWAVE
TROUGH PUSHING ACROSS THE NORTHERN PLAINS. THE ZONAL FLOW FOR TODAY
WILL MEAN A QUIETER DAY. HOWEVER...A SUBTLE UPPER LEVEL WAVE WILL
PUSH ACROSS CENTRAL/NORTHEAST KENTUCKY THIS AFTERNOON AND EVENING.
WHILE OPERATIONAL GUIDANCE SUGGESTS VERY LITTLE IF ANY PRECIPITATION
TODAY...HI RES MODELS HAVE BEEN CONSISTENT ON SHOWING ISOLATED TO
SCATTERED CONVECTION DEVELOPING TODAY. THE MODEL GUIDANCE DOESN`T
SEEM TO MATCH UP TO WHAT THE HI RES MODELS ARE SHOWING. GIVEN THE
RECENT HISTORY OF HI RES MODELS DOING FAIRLY WELL WITH
CONVECTION...HAVE OPTED TO GO WITH ISOLATED TO SCATTERED SHOWERS AND
STORMS THIS AFTERNOON WITH THE HIGHEST CORRIDOR OF POPS FROM SOUTH
CENTRAL KENTUCKY...INTO NORTHERN AND NORTHEAST KENTUCKY.
HOWEVER...CANNOT RULE OUT A FEW ISOLATED SHOWERS OR STORMS DEVELOPING
ON THE HIGHER TERRAIN TO THE SOUTHEAST. WITH MODEST PRECIPITABLE
WATER VALUES AROUND 1.7 AND VERY HIGH FREEZING LEVELS (>15KFT)
POTENTIAL MAY EXISTS FOR SOME PERIODS OF VERY HEAVY RAIN.
FORTUNATELY...STORM MOVEMENT SHOULD BE SUFFICIENT TO LIMIT ANY
FLOODING CONCERNS TODAY.
THE SHOWERS/STORMS TODAY WILL BE TIED TO THE PEAK INSTABILITY HOURS
FROM MID AFTERNOON TO EARLY EVENING...BEFORE DYING OFF. THIS WILL
YIELD A QUITE NIGHT ACROSS THE AREA TODAY. CLEARING SKIES COULD YIELD
SOME PATCHY FOG...BUT WE MAY KEEP ENOUGH WIND AGAIN TO LIMIT IT TO
SOME DEGREE. THE SHORTWAVE TROUGH OVER THE NORTHERN PLAINS WILL SEND
A WEAK COLD FRONT INTO THE OHIO RIVER VALLEY REGION. THIS WILL SPARK
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP ON
TUESDAY. THESE WILL TRACK SOUTHEAST ACROSS EASTERN KENTUCKY THROUGH
THE AFTERNOON AND EVENING HOURS. WITH MODEST 30-40KT BULK SHEAR
VALUES...THE POTENTIAL WILL EXISTS FOR SOME LINEAR STORM SEGMENTS
CAPABLE OF DAMAGING WINDS. PLAN TO CONTINUE TO HIGHLIGHT THIS
POTENTIAL IN THE HWO. THE FRONT WILL WASH OUT AND STALL OVER SOUTHERN
KENTUCKY BY THE EVENING HOURS WITH ACTIVITY DYING OUT WITH THE LOSS
OF DAYTIME HEATING.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 410 AM EDT MON SEP 1 2014
WARM WEATHER IS EXPECTED TO CONTINUE INTO THE EXTENDED PERIOD. THE
EXTENDED PERIOD OF THE FORECAST WILL BEGIN WITH THE TROUGH IN THE
NEAR TERM DEPARTING TO THE NORTH AND EAST...WITH A RATHER ZONAL
PATTERN TO START OVERALL. THE NEAR TERM COLD FRONT IS EXPECTED TO
BE DROPPING OR HAVE DROPPED ACROSS THE REGION AT THE START OF THE
PERIOD...FROM TUE NIGHT INTO EARLY ON WEDNESDAY AND BRING ISOLATED TO
SCATTERED CONVECTION. THE BOUNDARY SHOULD BECOME MORE ILL DEFINED AND
RATHER WASHED OUT ON WEDNESDAY AS IT REACHES THE TN VALLEY REGION.
WITH THE BOUNDARY IN THE AREA...CONVECTION WILL REMAIN POSSIBLE
MAINLY ACROSS THE SOUTH AND SOUTHEAST ON WEDNESDAY. MID AND UPPER
LEVEL RIDGING IS THEN EXPECTED TO BRIEFLY AMPLIFY ACROSS THE
SOUTHEASTERN AND MID ATLANTIC STATES THROUGH FRIDAY.
AS THE RIDGE BUILDS AND A SHORTWAVE TROUGH OR TWO IN THE ZONAL FLOW
MOVES FROM THE CENTRAL PLAINS TOWARD THE LOWER OH VALLEY REGION AND
INTO THE MIDDLE OH VALLEY REGION...WHAT IS LEFT OF THE BOUNDARY AND
DEEPER MOISTURE SHOULD ALSO BEGIN TO RETREAT BACK INTO THE REGION BY
WED NIGHT INTO THU. THIS SHOULD LEAD TO AN ADDITIONAL PERIOD WHERE
CONVECTION IS POSSIBLE. THE MODEL CONSENSUS IS FOR THE RIDGE TO
BUILD IN BEHIND THIS SHORTWAVE FOR THU NIGHT AND INTO EARLY ON FRI.
OVERALL...CONVECTION FROM THU NIGHT INTO FRIDAY MAY HAVE SOMEWHAT OF
A DIURNAL FLAVOR.
ALSO DURING THIS TIME...A SERIES OF TROUGHS WILL TRAVERSE THE
NORTHERN STREAM AND SEND A COLD FRONT SOUTH INTO AND GRADUALLY ACROSS
THE THE LOWER OH VALLEY REGION AND EASTERN KENTUCKY THIS WEEKEND.
THIS WILL BRING PERIOD OF UNSETTLED WEATHER...WITH PROLONGED CHANCES
FOR SHOWERS AND THUNDERSTORMS FROM SATURDAY INTO SUNDAY.
TEMPERATURES ARE EXPECTED TO AVERAGE NEAR TO A FEW DEGREES ABOVE
NORMAL FROM WED INTO SATURDAY FOR DAYTIME HIGHS...WITH OVERNIGHT LOW
HAVING THE GREATER DEPARTURE OF NEARLY 5 DEGREES ON AVERAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 155 PM EDT MON SEP 1 2014
A LINE OF SCATTERED SHOWERS AND THUNDERSTORMS ARE MOVING IN FROM THE
WEST. THIS LINE IS OUT AHEAD OF THE COLD FRONT IN THE WARM AIR. THERE
IS A BIT OF CURVATURE TO THE LINE OF HEAVIEST STORMS;...SO WILL BE
WATCHING FOR SOME POTENTIALLY STRONG WIND GUSTS AS THE LINE GOES
THROUGH. THE MERCER AND LINCOLN COUNTY MESONET SITES SAW WIND GUSTS
OF 30 MPH AS THE LINE WENT THROUGH. CURRENT THINKING IS THE MAX GUSTS
WILL STAY BELOW 40 MPH AND WILL BE IN THE 20 TO 30 MPH RANGE AS THE
STORMS MOVE INTO EASTERN KENTUCKY. THE HEATING WILL BE A LITTLE
BETTER...HOWEVER THE STORMS SEEM TO BE WEAKENING A LITTLE BIT. SOME
TEMPO IFR IS POSSIBLE WITH THE HEAVIEST STORMS. OTHERWISE VFR
CONDITIONS WILL PREVAIL UNTIL 6 TO 8Z WHEN SOME MVFR MIST MAY BE
EFFECTING THE TAF SITES. LOOKING FOR VSBY DOWN TO ABOUT 2 SM AT THE
TAF SITES BUT DOWN TO 1/2SM IN THE RIVER VALLEYS...ESPECIALLY IN
AREAS THAT GET RAIN TODAY. ONCE THE MIST CLEARS IN THE
MORNING...EXPECTING TO SEE SOME CONVECTION DEVELOP AGAIN TOMORROW.
THE CHANCE FOR STRONG THUNDERSTORMS IS GREATER FOR TOMORROW THAN IT
WAS TODAY. THE TIMING OF STORMS FOR TOMORROW IS TOO
UNCERTAIN...HOWEVER SHOULD BE AFTER 16Z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...KAS
LONG TERM...JP
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1221 PM CDT Mon Sep 1 2014
.UPDATE...
Issued at 1221 PM CDT MON SEP 1 2014
Updated the AVIATION section.
UPDATE Issued at 849 AM CDT MON SEP 1 2014
Clearly evident yesterday`s and even some of last night`s models
were unable to resolve and capture several ongoing elements. PoPs
have been modified to capture ongoing convection over the east
that wasn`t model depicted prior. Also, winds were up quicker than
forecast this morning. 12z upper air data shows 30-40kt low level
jet already established. Thus, that leads us to the fact we are
already at Lake Wind Advisory criteria. Given it`s the holiday,
will go ahead with one. Gusty southwest winds expected 10 to 20
mph with 25+ mph winds possible at times. Not necessarily the
optimum trajectory, but quite breezy none the less. Meanwhile,
kept chance of convection going more aggressively than previously
forecast, given the amount of heating we will see ahead of the
decaying activity to our west. The HRRR shows some development in
this region of less cloud cover over the next several hours,
before dying off later in the afternoon. Will see if this actually
comes to fruition. For now, will keep PoPs in the chance category.
&&
.SHORT TERM...(Today through Wednesday)
Issued at 200 AM CDT MON SEP 1 2014
MCS dropping down across MO will spread its clouds into/across PAH
FA this morning. It will also lay out some boundaries, the primary
one of which lays out across our northern tier this afternoon,
where we`ll have a slgt/small chance mentionable Pop.
As the mean energy in the long wave moves across the MS and Wabash
river valleys tonight and Tuesday, it will drag this primary
boundary into the heart of the FA and result in an uptick in Pops
to likely cat or better, particularly during the day Tuesday. This
has been a consistent model signal and looks a good bet with fropa
thru much of the area by 00Z Wed.
The front/boundary hangs up across our southern tier or just to
the south Tue night, and returns as a warm sector boundary late
Tue night and Wed. This is indicated by several model members so we
adjusted Pops accordingly.
Temps look to remain summerlike at or just above climo norms from
the mid/upr 80s to near 90 for highs, and generally in the
u60s/lower 70s for lows, with continued muggy dew points.
.LONG TERM...(Wednesday Night through Sunday)
Issued at 302 AM CDT MON SEP 1 2014
The PAH forecast area will be under the stabilizing influence
(aloft) of a broad mid level ridge late in the week, though some
models indicate that, with the substantial diurnal lower trop
instability present each day, some deep moist convection may be
strong enough to get past the warm mid level cap in some locations
during the daytime.
Meanwhile, a nrn stream longwave trof will be in the process of
lowering mid level heights across most of the CONUS. A sfc cold
front is forecast to sink sewd into the OH river valley by sometime
early Sat, with some timing differences among the med range models.
This feature will provide additional focus for lifting of abundant
moist air, thus PoPs are now 40-50 percent during the day Sat behind
the front. By Sunday, a drier air mass should be making its way into
our region, cutting off pcpn. However, the GFS and its ensemble
means suggested the center of the high (over the upper Midwest) may
be farther east than the ECMWF and its ensemble means indicated, and
therefore some warm advection showers/tstms may erupt just to our
west. We will have to wait and see how long the drying effects of
the dome of high sfc pressure actually last.
Warm and humid conditions will prevail late in the week ahead of the
front, with heat indices peaking around 100 Thu and Fri, but
especially Fri. For this forecast package, the frontal passage
should provide us end-of-the-weekend dewpoints in the 60s along with
&&
.AVIATION...
Issued at 1221 PM CDT MON SEP 1 2014
Prob of convection not high enough to include at the Terminals this
afternoon. Gusty SW winds will persist, 10-20kt +. Ocnl clouds aoa
12k/ft will continue, with sct-bkn025-035 expected, gradually
higher bases with time. Kept best chance of convection tonight,
within Prob30`s mainly aft 06z as convective chances increase
markedly after midnight. Winds will back to the south and fall to
aob 10 kts tonight.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...LAKE WIND ADVISORY until 6 PM CDT this evening FOR ILZ075>078-
080>094.
MO...LAKE WIND ADVISORY until 6 PM CDT this evening FOR MOZ076-086-
087-100-107>112-114.
IN...LAKE WIND ADVISORY until 6 PM CDT this evening FOR INZ081-082-
085>088.
KY...LAKE WIND ADVISORY until 6 PM CDT this evening FOR KYZ001>022.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
121 PM EDT Mon Sep 1 2014
...Updated Aviation Discussion...
...Forecast Update...
Issued at 1153 AM EDT Mon Sep 1 2014
A small cluster of showers with some embedded thunder is progressing
quickly across central Kentucky and will be capable of producing
some locally gusty winds into the 40-50 mph range as it moves into
the Green River Lake region and an area of maximized DCAPE and
surface instability. Have updated the forecast grids to reflect
this area of precipitation, along with the few other showers that
are scattered around the area.
Issued at 859 AM EDT Mon Sep 1 2014
Widely scattered showers have formed in a corridor of higher surface
dew points and CAPE, and diminished CIN, from Memphis to Detroit.
have upped PoPs for a few hours this morning in the northwest LMK
CWA to account for this.
.SHORT TERM (Now through Tuesday)...
Issued at 310 AM EDT Mon Sep 1 2014
A slow-moving cool front to our northwest will bring a noticeable
increase in southwesterly winds today, with gusts of 15 to 25 mph
likely this afternoon. First off though we may see some isolated
low-topped showers this morning, with convergence along a weak
low-level jet early this morning already initiating some in central
IN. HRRR indicates better coverage than what I`ll have in my
forecast, as current guidance coverage already is too high.
Cloud cover from the moist low levels and as additional moisture
streams into the region today in a deep southwesterly flow should
keep high temperatures from getting too far above normal, with
readings likely topping out in the mid to upper 80s. The focus for
storms this evening will be to our west and northwest, closer to the
approaching front. These storms may be able to get into our southern
Indiana counties around or after midnight.
There still are some uncertainties about how convective development
will occur from early to late Tuesday, as a lot will depend on the
evolution of these storms moving into our region. Should those
storms get in here more toward daybreak, then convective debris
could be enough to prevent furthern development during the day
Tuesday, despite relatively high precipitable waters. Should those
storms die off overnight and leave boundaries behind, Tuesday could
become more active with heating. Will leave in likely pops for the
day Tuesday, as would lean more towards the latter solution that
we`ll see a few breaks in the clouds to generate more storms.
.LONG TERM (Tuesday Night through Sunday)...
Issued at 305 AM EDT Mon Sep 01 2014
Tuesday Night and Wednesday...
Surface high pressure will slide over the Ohio Valley behind the
nearly washed out front to our south on Tuesday night. An isolated
shower or storm could linger into the evening hours across the south
or east CWA, otherwise expect a dry and slightly cooler night. Lows
should drop into the upper 60s and around 70. Isolated or widely
scattered diurnally driven showers/storms are expected to be
possible across southern KY on Wednesday. Most areas will stay dry
with mostly sunny skies and highs in the 85 to 88 degree range.
Wednesday Night - Friday...
The southern CONUS upper ridge will build over the area to end the
week, however this will not be enough to suppress diurnally
driven convection each afternoon and early evening. Will continue
mention of isolated to widely scattered coverage on Thursday, with
better coverage on Friday more solidly in the scattered range. Along
with this ridge, the heat and humidity will return with highs in the
upper 80s to around 90 each day. With dew points in the low 70s each
day, conditions will feel quite muggy. The environment should become
pretty unstable each afternoon/evening, however the lack of deep
layer flow will keep any convection pulse in nature. Lows by
Thursday night will be back in the low 70s.
Friday Night - Saturday Night...
The upper ridge will be suppressed southward to start the weekend, as
a wave skirts along the eastern US/Canada border. This will drag a
stronger cold front toward our moist and unstable airmass, keeping
scattered storms in play on Friday night. Saturday should bring the
best chance of storms for the whole forecast period as the front
tries to slide through. Have gone with 40-50% coverage. With
slightly better deep layer flow over the area, the threat for a few
stronger storms seems reasonable. Biggest concern would be gusty
winds, along with cloud to ground lightning and brief heavy
rainfall. A few storms could linger in our south and east Saturday
evening.
Expect more mild lows on Friday night with the mercury only dropping
to the low 70s. Highs on Saturday will be dependent on convection
and where the frontal boundary resides, but it looks like temps will
max out around 80 north, to the mid or upper 80s south. Lows
Saturday night will be cooler on the north side of the boundary.
Look for readings in the 60s.
Sunday...
Surface high pressure takes back over on Sunday, bringing dry and
cooler conditions to start the new work week. Look for highs in the
upper 70s and low 80s, with lows Sunday night expected to be in the
upper 50s and low 60s!
&&
.AVIATION (18Z TAF Update)...
Issued at 121 PM EDT Mon Sep 1 2014
Scattered showers and isolated thunderstorms will be possible this
afternoon in the warm, humid, unstable air over central Kentucky.
Any convection will be moving quickly and would affect any one
airfield only very briefly. For now will stick with VCSH, and
monitor radar closely for any helpful AMDs.
Winds this afternoon will be gusty from the southwest, gusting into
the 22 to 26 knot range.
Tonight winds will settle down though there will still be a
southerly breeze around 5 to 9 knots as we sit in accelerated flow
ahead of an approaching cold front. Isolated convection will be
possible, but at this time chances appear slight enough to omit from
the TAFs.
Toward morning that cold front will be entering the region, bringing
a band of showers and thunderstorms along with it. Right now will
time it into SDF around dawn and a little later at LEX/BWG, though
they could end up coming in a little quicker than that.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........13
Short Term.....RJS
Long Term......BJS
Aviation.......13
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1153 AM EDT Mon Sep 1 2014
...Forecast Update...
Issued at 1153 AM EDT Mon Sep 1 2014
A small cluster of showers with some embedded thunder is progressing
quickly across central Kentucky and will be capable of producing
some locally gusty winds into the 40-50 mph range as it moves into
the Green River Lake region and an area of maximized DCAPE and
surface instability. Have updated the forecast grids to reflect
this area of precipitation, along with the few other showers that
are scattered around the area.
Issued at 859 AM EDT Mon Sep 1 2014
Widely scattered showers have formed in a corridor of higher surface
dew points and CAPE, and diminished CIN, from Memphis to Detroit.
have upped PoPs for a few hours this morning in the northwest LMK
CWA to account for this.
.SHORT TERM (Now through Tuesday)...
Issued at 310 AM EDT Mon Sep 1 2014
A slow-moving cool front to our northwest will bring a noticeable
increase in southwesterly winds today, with gusts of 15 to 25 mph
likely this afternoon. First off though we may see some isolated
low-topped showers this morning, with convergence along a weak
low-level jet early this morning already initiating some in central
IN. HRRR indicates better coverage than what I`ll have in my
forecast, as current guidance coverage already is too high.
Cloud cover from the moist low levels and as additional moisture
streams into the region today in a deep southwesterly flow should
keep high temperatures from getting too far above normal, with
readings likely topping out in the mid to upper 80s. The focus for
storms this evening will be to our west and northwest, closer to the
approaching front. These storms may be able to get into our southern
Indiana counties around or after midnight.
There still are some uncertainties about how convective development
will occur from early to late Tuesday, as a lot will depend on the
evolution of these storms moving into our region. Should those
storms get in here more toward daybreak, then convective debris
could be enough to prevent furthern development during the day
Tuesday, despite relatively high precipitable waters. Should those
storms die off overnight and leave boundaries behind, Tuesday could
become more active with heating. Will leave in likely pops for the
day Tuesday, as would lean more towards the latter solution that
we`ll see a few breaks in the clouds to generate more storms.
.LONG TERM (Tuesday Night through Sunday)...
Issued at 305 AM EDT Mon Sep 01 2014
Tuesday Night and Wednesday...
Surface high pressure will slide over the Ohio Valley behind the
nearly washed out front to our south on Tuesday night. An isolated
shower or storm could linger into the evening hours across the south
or east CWA, otherwise expect a dry and slightly cooler night. Lows
should drop into the upper 60s and around 70. Isolated or widely
scattered diurnally driven showers/storms are expected to be
possible across southern KY on Wednesday. Most areas will stay dry
with mostly sunny skies and highs in the 85 to 88 degree range.
Wednesday Night - Friday...
The southern CONUS upper ridge will build over the area to end the
week, however this will not be enough to suppress diurnally
driven convection each afternoon and early evening. Will continue
mention of isolated to widely scattered coverage on Thursday, with
better coverage on Friday more solidly in the scattered range. Along
with this ridge, the heat and humidity will return with highs in the
upper 80s to around 90 each day. With dew points in the low 70s each
day, conditions will feel quite muggy. The environment should become
pretty unstable each afternoon/evening, however the lack of deep
layer flow will keep any convection pulse in nature. Lows by
Thursday night will be back in the low 70s.
Friday Night - Saturday Night...
The upper ridge will be suppressed southward to start the weekend, as
a wave skirts along the eastern US/Canada border. This will drag a
stronger cold front toward our moist and unstable airmass, keeping
scattered storms in play on Friday night. Saturday should bring the
best chance of storms for the whole forecast period as the front
tries to slide through. Have gone with 40-50% coverage. With
slightly better deep layer flow over the area, the threat for a few
stronger storms seems reasonable. Biggest concern would be gusty
winds, along with cloud to ground lightning and brief heavy
rainfall. A few storms could linger in our south and east Saturday
evening.
Expect more mild lows on Friday night with the mercury only dropping
to the low 70s. Highs on Saturday will be dependent on convection
and where the frontal boundary resides, but it looks like temps will
max out around 80 north, to the mid or upper 80s south. Lows
Saturday night will be cooler on the north side of the boundary.
Look for readings in the 60s.
Sunday...
Surface high pressure takes back over on Sunday, bringing dry and
cooler conditions to start the new work week. Look for highs in the
upper 70s and low 80s, with lows Sunday night expected to be in the
upper 50s and low 60s!
&&
.AVIATION (12Z TAF Update)...
Issued at 640 AM EDT Mon Sep 1 2014
Have a few light rain showers forming north of a KSDF/KLEX line this
hour, but even should the rain make the terminals it should be light
enough not to reduce visibility much. The bigger factor now is
ceilings, with them hovering between MVFR and IFR at those two
sites, and KBWG may see it soon too. These clouds will lift by mid
morning. An isolated storm still cannot be ruled out later this
afternoon, but again coverage too limited to put in TAFs at this
time. Should see more storms coming in early Tuesday, first at KSDF
as a cool front approaches the region.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........13
Short Term.....RJS
Long Term......BJS
Aviation.......RJS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1048 AM EDT MON SEP 1 2014
.UPDATE...
ISSUED AT 1048 AM EDT MON SEP 1 2014
UPDATED THE FORECAST TO INCLUDE ALL OF EASTERN KENTUCKY IN THE CHANCE
OF PRECIPITATION TODAY BASED ON THE HIGH HRRR AND RUC MODEL OUTPUT AS
WELL AS THE CURRENT RADAR. BASED ON THE NAM BUFFER SOUNDINGS...DO
HAVE SOME CONCERN THAT SOME OF THE STORMS TODAY COULD PRODUCE
STRONG...BUT SUB SEVERE...WIND GUSTS TODAY. THERE IS SUFFICIENT
INSTABILITY AND SOME DRY AIR ALOFT THAT WOULD MAKE THIS FAVORABLE.
STILL HAVE CONCERN FOR SOME STRONG STORMS FOR TUESDAY AFTERNOON AND
EVENING AS WELL. WOULD NOT BE TOO SURPRISED TO SEE EASTERN KENTUCKY IN
AN SPC SLIGHT RISK BOX FOR TOMORROW. THE REST OF THE FORECAST IS ON TRACK.
UPDATE ISSUED AT 647 AM EDT MON SEP 1 2014
CLOUD COVER HAS EXPANDED A BIT FROM EARLIER...SO HAVE ADJUSTED THE
SKY COVER TO REFLECT CLOUDIER SKIES THROUGH DAYBREAK. ALSO ADJUSTED
TEMPERATURES UP A FEW DEGREES ACROSS THE BOARD AS THE CLOUDS ARE
HOLDING TEMPERATURES UP MAINLY IN THE LOW 70S. HRRR CONTINUES TO
PAINT OUT SOME ISOLATED TO SCATTERED SHOWERS AND STORMS THIS
AFTERNOON...AND THE 06Z NAM HAS ALSO NOW SUPPORTING A FEW SHOWERS AND
STORMS. THUS IT DOES LOOK LIKE SOME ACTIVITY CAN BE EXPECTED BY THE
AFTERNOON HOURS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 331 AM EDT MON SEP 1 2014
ZONAL FLOW RESIDES ACROSS KENTUCKY THIS MORNING...WITH A SHORTWAVE
TROUGH PUSHING ACROSS THE NORTHERN PLAINS. THE ZONAL FLOW FOR TODAY
WILL MEAN A QUIETER DAY. HOWEVER...A SUBTLE UPPER LEVEL WAVE WILL
PUSH ACROSS CENTRAL/NORTHEAST KENTUCKY THIS AFTERNOON AND EVENING.
WHILE OPERATIONAL GUIDANCE SUGGESTS VERY LITTLE IF ANY PRECIPITATION
TODAY...HI RES MODELS HAVE BEEN CONSISTENT ON SHOWING ISOLATED TO
SCATTERED CONVECTION DEVELOPING TODAY. THE MODEL GUIDANCE DOESN`T
SEEM TO MATCH UP TO WHAT THE HI RES MODELS ARE SHOWING. GIVEN THE
RECENT HISTORY OF HI RES MODELS DOING FAIRLY WELL WITH
CONVECTION...HAVE OPTED TO GO WITH ISOLATED TO SCATTERED SHOWERS AND
STORMS THIS AFTERNOON WITH THE HIGHEST CORRIDOR OF POPS FROM SOUTH
CENTRAL KENTUCKY...INTO NORTHERN AND NORTHEAST KENTUCKY.
HOWEVER...CANNOT RULE OUT A FEW ISOLATED SHOWERS OR STORMS DEVELOPING
ON THE HIGHER TERRAIN TO THE SOUTHEAST. WITH MODEST PRECIPITABLE
WATER VALUES AROUND 1.7 AND VERY HIGH FREEZING LEVELS (>15KFT)
POTENTIAL MAY EXISTS FOR SOME PERIODS OF VERY HEAVY RAIN.
FORTUNATELY...STORM MOVEMENT SHOULD BE SUFFICIENT TO LIMIT ANY
FLOODING CONCERNS TODAY.
THE SHOWERS/STORMS TODAY WILL BE TIED TO THE PEAK INSTABILITY HOURS
FROM MID AFTERNOON TO EARLY EVENING...BEFORE DYING OFF. THIS WILL
YIELD A QUITE NIGHT ACROSS THE AREA TODAY. CLEARING SKIES COULD YIELD
SOME PATCHY FOG...BUT WE MAY KEEP ENOUGH WIND AGAIN TO LIMIT IT TO
SOME DEGREE. THE SHORTWAVE TROUGH OVER THE NORTHERN PLAINS WILL SEND
A WEAK COLD FRONT INTO THE OHIO RIVER VALLEY REGION. THIS WILL SPARK
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP ON
TUESDAY. THESE WILL TRACK SOUTHEAST ACROSS EASTERN KENTUCKY THROUGH
THE AFTERNOON AND EVENING HOURS. WITH MODEST 30-40KT BULK SHEAR
VALUES...THE POTENTIAL WILL EXISTS FOR SOME LINEAR STORM SEGMENTS
CAPABLE OF DAMAGING WINDS. PLAN TO CONTINUE TO HIGHLIGHT THIS
POTENTIAL IN THE HWO. THE FRONT WILL WASH OUT AND STALL OVER SOUTHERN
KENTUCKY BY THE EVENING HOURS WITH ACTIVITY DYING OUT WITH THE LOSS
OF DAYTIME HEATING.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 410 AM EDT MON SEP 1 2014
WARM WEATHER IS EXPECTED TO CONTINUE INTO THE EXTENDED PERIOD. THE
EXTENDED PERIOD OF THE FORECAST WILL BEGIN WITH THE TROUGH IN THE
NEAR TERM DEPARTING TO THE NORTH AND EAST...WITH A RATHER ZONAL
PATTERN TO START OVERALL. THE NEAR TERM COLD FRONT IS EXPECTED TO
BE DROPPING OR HAVE DROPPED ACROSS THE REGION AT THE START OF THE
PERIOD...FROM TUE NIGHT INTO EARLY ON WEDNESDAY AND BRING ISOLATED TO
SCATTERED CONVECTION. THE BOUNDARY SHOULD BECOME MORE ILL DEFINED AND
RATHER WASHED OUT ON WEDNESDAY AS IT REACHES THE TN VALLEY REGION.
WITH THE BOUNDARY IN THE AREA...CONVECTION WILL REMAIN POSSIBLE
MAINLY ACROSS THE SOUTH AND SOUTHEAST ON WEDNESDAY. MID AND UPPER
LEVEL RIDGING IS THEN EXPECTED TO BRIEFLY AMPLIFY ACROSS THE
SOUTHEASTERN AND MID ATLANTIC STATES THROUGH FRIDAY.
AS THE RIDGE BUILDS AND A SHORTWAVE TROUGH OR TWO IN THE ZONAL FLOW
MOVES FROM THE CENTRAL PLAINS TOWARD THE LOWER OH VALLEY REGION AND
INTO THE MIDDLE OH VALLEY REGION...WHAT IS LEFT OF THE BOUNDARY AND
DEEPER MOISTURE SHOULD ALSO BEGIN TO RETREAT BACK INTO THE REGION BY
WED NIGHT INTO THU. THIS SHOULD LEAD TO AN ADDITIONAL PERIOD WHERE
CONVECTION IS POSSIBLE. THE MODEL CONSENSUS IS FOR THE RIDGE TO
BUILD IN BEHIND THIS SHORTWAVE FOR THU NIGHT AND INTO EARLY ON FRI.
OVERALL...CONVECTION FROM THU NIGHT INTO FRIDAY MAY HAVE SOMEWHAT OF
A DIURNAL FLAVOR.
ALSO DURING THIS TIME...A SERIES OF TROUGHS WILL TRAVERSE THE
NORTHERN STREAM AND SEND A COLD FRONT SOUTH INTO AND GRADUALLY ACROSS
THE THE LOWER OH VALLEY REGION AND EASTERN KENTUCKY THIS WEEKEND.
THIS WILL BRING PERIOD OF UNSETTLED WEATHER...WITH PROLONGED CHANCES
FOR SHOWERS AND THUNDERSTORMS FROM SATURDAY INTO SUNDAY.
TEMPERATURES ARE EXPECTED TO AVERAGE NEAR TO A FEW DEGREES ABOVE
NORMAL FROM WED INTO SATURDAY FOR DAYTIME HIGHS...WITH OVERNIGHT LOW
HAVING THE GREATER DEPARTURE OF NEARLY 5 DEGREES ON AVERAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 647 AM EDT MON SEP 1 2014
LOW CLOUDS HAVE DEVELOPED AND SPREAD ACROSS MUCH OF EASTERN KENTUCKY
THIS MORNING. FOR THE MOST PART...MVFR CIGS ARE BEING REPORTED.
HOWEVER...A FEW SPOTS IN THE NORTH MAY BE DOWN TO IFR CIGS. WE SHOULD
SEE GRADUAL IMPROVEMENT THROUGH THE MORNING HOURS BEFORE VFR
CONDITIONS RETURN BY MIDDAY. ISOLATED TO SCATTERED SHOWERS AND STORMS
STILL LOOK LIKE A POSSIBILITY THIS AFTERNOON...BUT NO ENOUGH COVERAGE
OR CONFIDENCE TO INCLUDE IN THE TAFS. VFR CONDITIONS LOOK TO CONTINUE
THROUGH TONIGHT WITH ONLY SOME VERY PATCHY VALLEY FOG. AT THIS
TIME...THIS IS NOT EXPECTED TO IMPACT THE TAF SITES TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...KAS
LONG TERM...JP
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
849 AM CDT Mon Sep 1 2014
.UPDATE...
Issued at 849 AM CDT MON SEP 1 2014
Clearly evident yesterday`s and even some of last night`s models
were unable to resolve and capture several ongoing elements. PoPs
have been modified to capture ongoing convection over the east
that wasn`t model depicted prior. Also, winds were up quicker than
forecast this morning. 12z upper air data shows 30-40kt low level
jet already established. Thus, that leads us to the fact we are
already at Lake Wind Advisory criteria. Given it`s the holiday,
will go ahead with one. Gusty southwest winds expected 10 to 20
mph with 25+ mph winds possible at times. Not necessarily the
optimum trajectory, but quite breezy none the less. Meanwhile,
kept chance of convection going more aggressively than previously
forecast, given the amount of heating we will see ahead of the
decaying activity to our west. The HRRR shows some development in
this region of less cloud cover over the next several hours,
before dying off later in the afternoon. Will see if this actually
comes to fruition. For now, will keep PoPs in the chance category.
&&
.SHORT TERM...(Today through Wednesday)
Issued at 200 AM CDT MON SEP 1 2014
MCS dropping down across MO will spread its clouds into/across PAH
FA this morning. It will also lay out some boundaries, the primary
one of which lays out across our northern tier this afternoon,
where we`ll have a slgt/small chance mentionable Pop.
As the mean energy in the long wave moves across the MS and Wabash
river valleys tonight and Tuesday, it will drag this primary
boundary into the heart of the FA and result in an uptick in Pops
to likely cat or better, particularly during the day Tuesday. This
has been a consistent model signal and looks a good bet with fropa
thru much of the area by 00Z Wed.
The front/boundary hangs up across our southern tier or just to
the south Tue night, and returns as a warm sector boundary late
Tue night and Wed. This is indicated by several model members so we
adjusted Pops accordingly.
Temps look to remain summerlike at or just above climo norms from
the mid/upr 80s to near 90 for highs, and generally in the
u60s/lower 70s for lows, with continued muggy dew points.
.LONG TERM...(Wednesday Night through Sunday)
Issued at 302 AM CDT MON SEP 1 2014
The PAH forecast area will be under the stabilizing influence
(aloft) of a broad mid level ridge late in the week, though some
models indicate that, with the substantial diurnal lower trop
instability present each day, some deep moist convection may be
strong enough to get past the warm mid level cap in some locations
during the daytime.
Meanwhile, a nrn stream longwave trof will be in the process of
lowering mid level heights across most of the CONUS. A sfc cold
front is forecast to sink sewd into the OH river valley by sometime
early Sat, with some timing differences among the med range models.
This feature will provide additional focus for lifting of abundant
moist air, thus PoPs are now 40-50 percent during the day Sat behind
the front. By Sunday, a drier air mass should be making its way into
our region, cutting off pcpn. However, the GFS and its ensemble
means suggested the center of the high (over the upper Midwest) may
be farther east than the ECMWF and its ensemble means indicated, and
therefore some warm advection showers/tstms may erupt just to our
west. We will have to wait and see how long the drying effects of
the dome of high sfc pressure actually last.
Warm and humid conditions will prevail late in the week ahead of the
front, with heat indices peaking around 100 Thu and Fri, but
especially Fri. For this forecast package, the frontal passage
should provide us end-of-the-weekend dewpoints in the 60s along with
&&
.AVIATION...
Issued at 200 AM CDT MON SEP 1 2014
Will monitor tonight for any possible developing restrictions to
vsbys pre dawn. Cigs develop as MCS moves this way, restrictions
to MVFR possible at times, but believe will generally stay VFR.
Anticipate increasing gradient/winds during the day ahead of
approaching boundary. Pops enter forecast tonight but refrain from
terminal mention at this writing.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...LAKE WIND ADVISORY until 6 PM CDT this evening FOR ILZ075>078-
080>094.
MO...LAKE WIND ADVISORY until 6 PM CDT this evening FOR MOZ076-086-
087-100-107>112-114.
IN...LAKE WIND ADVISORY until 6 PM CDT this evening FOR INZ081-082-
085>088.
KY...LAKE WIND ADVISORY until 6 PM CDT this evening FOR KYZ001>022.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
859 AM EDT Mon Sep 1 2014
...Forecast Update...
Issued at 859 AM EDT Mon Sep 1 2014
Widely scattered showers have formed in a corridor of higher surface
dew points and CAPE, and diminished CIN, from Memphis to Detroit.
have upped PoPs for a few hours this morning in the northwest LMK
CWA to account for this.
.SHORT TERM (Now through Tuesday)...
Issued at 310 AM EDT Mon Sep 1 2014
A slow-moving cool front to our northwest will bring a noticeable
increase in southwesterly winds today, with gusts of 15 to 25 mph
likely this afternoon. First off though we may see some isolated
low-topped showers this morning, with convergence along a weak
low-level jet early this morning already initiating some in central
IN. HRRR indicates better coverage than what I`ll have in my
forecast, as current guidance coverage already is too high.
Cloud cover from the moist low levels and as additional moisture
streams into the region today in a deep southwesterly flow should
keep high temperatures from getting too far above normal, with
readings likely topping out in the mid to upper 80s. The focus for
storms this evening will be to our west and northwest, closer to the
approaching front. These storms may be able to get into our southern
Indiana counties around or after midnight.
There still are some uncertainties about how convective development
will occur from early to late Tuesday, as a lot will depend on the
evolution of these storms moving into our region. Should those
storms get in here more toward daybreak, then convective debris
could be enough to prevent furthern development during the day
Tuesday, despite relatively high precipitable waters. Should those
storms die off overnight and leave boundaries behind, Tuesday could
become more active with heating. Will leave in likely pops for the
day Tuesday, as would lean more towards the latter solution that
we`ll see a few breaks in the clouds to generate more storms.
.LONG TERM (Tuesday Night through Sunday)...
Issued at 305 AM EDT Mon Sep 01 2014
Tuesday Night and Wednesday...
Surface high pressure will slide over the Ohio Valley behind the
nearly washed out front to our south on Tuesday night. An isolated
shower or storm could linger into the evening hours across the south
or east CWA, otherwise expect a dry and slightly cooler night. Lows
should drop into the upper 60s and around 70. Isolated or widely
scattered diurnally driven showers/storms are expected to be
possible across southern KY on Wednesday. Most areas will stay dry
with mostly sunny skies and highs in the 85 to 88 degree range.
Wednesday Night - Friday...
The southern CONUS upper ridge will build over the area to end the
week, however this will not be enough to suppress diurnally
driven convection each afternoon and early evening. Will continue
mention of isolated to widely scattered coverage on Thursday, with
better coverage on Friday more solidly in the scattered range. Along
with this ridge, the heat and humidity will return with highs in the
upper 80s to around 90 each day. With dew points in the low 70s each
day, conditions will feel quite muggy. The environment should become
pretty unstable each afternoon/evening, however the lack of deep
layer flow will keep any convection pulse in nature. Lows by
Thursday night will be back in the low 70s.
Friday Night - Saturday Night...
The upper ridge will be suppressed southward to start the weekend, as
a wave skirts along the eastern US/Canada border. This will drag a
stronger cold front toward our moist and unstable airmass, keeping
scattered storms in play on Friday night. Saturday should bring the
best chance of storms for the whole forecast period as the front
tries to slide through. Have gone with 40-50% coverage. With
slightly better deep layer flow over the area, the threat for a few
stronger storms seems reasonable. Biggest concern would be gusty
winds, along with cloud to ground lightning and brief heavy
rainfall. A few storms could linger in our south and east Saturday
evening.
Expect more mild lows on Friday night with the mercury only dropping
to the low 70s. Highs on Saturday will be dependent on convection
and where the frontal boundary resides, but it looks like temps will
max out around 80 north, to the mid or upper 80s south. Lows
Saturday night will be cooler on the north side of the boundary.
Look for readings in the 60s.
Sunday...
Surface high pressure takes back over on Sunday, bringing dry and
cooler conditions to start the new work week. Look for highs in the
upper 70s and low 80s, with lows Sunday night expected to be in the
upper 50s and low 60s!
&&
.AVIATION (12Z TAF Update)...
Issued at 640 AM EDT Mon Sep 1 2014
Have a few light rain showers forming north of a KSDF/KLEX line this
hour, but even should the rain make the terminals it should be light
enough not to reduce visibility much. The bigger factor now is
ceilings, with them hovering between MVFR and IFR at those two
sites, and KBWG may see it soon too. These clouds will lift by mid
morning. An isolated storm still cannot be ruled out later this
afternoon, but again coverage too limited to put in TAFs at this
time. Should see more storms coming in early Tuesday, first at KSDF
as a cool front approaches the region.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........13
Short Term.....RJS
Long Term......BJS
Aviation.......RJS
AREA FORECAST DISCUSSION
NWS JACKSON KY
647 AM EDT MON SEP 1 2014
.UPDATE...
ISSUED AT 647 AM EDT MON SEP 1 2014
CLOUD COVER HAS EXPANDED A BIT FROM EARLIER...SO HAVE ADJUSTED THE
SKY COVER TO REFLECT CLOUDIER SKIES THROUGH DAYBREAK. ALSO ADJUSTED
TEMPERATURES UP A FEW DEGREES ACROSS THE BOARD AS THE CLOUDS ARE
HOLDING TEMPERATURES UP MAINLY IN THE LOW 70S. HRRR CONTINUES TO
PAINT OUT SOME ISOLATED TO SCATTERED SHOWERS AND STORMS THIS
AFTERNOON...AND THE 06Z NAM HAS ALSO NOW SUPPORTING A FEW SHOWERS AND
STORMS. THUS IT DOES LOOK LIKE SOME ACTIVITY CAN BE EXPECTED BY THE
AFTERNOON HOURS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 331 AM EDT MON SEP 1 2014
ZONAL FLOW RESIDES ACROSS KENTUCKY THIS MORNING...WITH A SHORTWAVE
TROUGH PUSHING ACROSS THE NORTHERN PLAINS. THE ZONAL FLOW FOR TODAY
WILL MEAN A QUIETER DAY. HOWEVER...A SUBTLE UPPER LEVEL WAVE WILL
PUSH ACROSS CENTRAL/NORTHEAST KENTUCKY THIS AFTERNOON AND EVENING.
WHILE OPERATIONAL GUIDANCE SUGGESTS VERY LITTLE IF ANY PRECIPITATION
TODAY...HI RES MODELS HAVE BEEN CONSISTENT ON SHOWING ISOLATED TO
SCATTERED CONVECTION DEVELOPING TODAY. THE MODEL GUIDANCE DOESN`T
SEEM TO MATCH UP TO WHAT THE HI RES MODELS ARE SHOWING. GIVEN THE
RECENT HISTORY OF HI RES MODELS DOING FAIRLY WELL WITH
CONVECTION...HAVE OPTED TO GO WITH ISOLATED TO SCATTERED SHOWERS AND
STORMS THIS AFTERNOON WITH THE HIGHEST CORRIDOR OF POPS FROM SOUTH
CENTRAL KENTUCKY...INTO NORTHERN AND NORTHEAST KENTUCKY.
HOWEVER...CANNOT RULE OUT A FEW ISOLATED SHOWERS OR STORMS DEVELOPING
ON THE HIGHER TERRAIN TO THE SOUTHEAST. WITH MODEST PW`S AROUND 1.7
AND VERY HIGH FREEZING LEVELS (>15KFT) POTENTIAL MAY EXISTS FOR SOME
PERIODS OF VERY HEAVY RAIN. FORTUNATELY...STORM MOVEMENT SHOULD BE
SUFFICIENT TO LIMIT ANY FLOODING CONCERNS TODAY.
THE SHOWERS/STORMS TODAY WILL BE TIED TO THE PEAK INSTABILITY HOURS
FROM MID AFTERNOON TO EARLY EVENING...BEFORE DYING OFF. THIS WILL
YIELD A QUITE NIGHT ACROSS THE AREA TODAY. CLEARING SKIES COULD YIELD
SOME PATCHY FOG...BUT WE MAY KEEP ENOUGH WIND AGAIN TO LIMIT IT TO
SOME DEGREE. THE SHORTWAVE TROUGH OVER THE NORTHERN PLAINS WILL SEND
A WEAK COLD FRONT INTO THE OHIO RIVER VALLEY REGION. THIS WILL SPARK
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP ON
TUESDAY. THESE WILL TRACK SOUTHEAST ACROSS EASTERN KENTUCKY THROUGH
THE AFTERNOON AND EVENING HOURS. WITH MODEST 30-40KT BULK SHEAR
VALUES...THE POTENTIAL WILL EXISTS FOR SOME LINEAR STORM SEGMENTS
CAPABLE OF DAMAGING WINDS. PLAN TO CONTINUE TO HIGHLIGHT THIS
POTENTIAL IN THE HWO. THE FRONT WILL WASH OUT AND STALL OVER SOUTHERN
KENTUCKY BY THE EVENING HOURS WITH ACTIVITY DYING OUT WITH THE LOSS
OF DAYTIME HEATING.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 410 AM EDT MON SEP 1 2014
WARM WEATHER IS EXPECTED TO CONTINUE INTO THE EXTENDED PERIOD. THE
EXTENDED PERIOD OF THE FORECAST WILL BEGIN WITH THE TROUGH IN THE
NEAR TERM DEPARTING TO THE NORTH AND EAST...WITH A RATHER ZONAL
PATTERN TO START OVERALL. THE NEAR TERM COLD FRONT IS EXPECTED TO
BE DROPPING OR HAVE DROPPED ACROSS THE REGION AT THE START OF THE
PERIOD...FROM TUE NIGHT INTO EARLY ON WEDNESDAY AND BRING ISOLATED TO
SCATTERED CONVECTION. THE BOUNDARY SHOULD BECOME MORE ILL DEFINED AND
RATHER WASHED OUT ON WEDNESDAY AS IT REACHES THE TN VALLEY REGION.
WITH THE BOUNDARY IN THE AREA...CONVECTION WILL REMAIN POSSIBLE
MAINLY ACROSS THE SOUTH AND SOUTHEAST ON WEDNESDAY. MID AND UPPER
LEVEL RIDGING IS THEN EXPECTED TO BRIEFLY AMPLIFY ACROSS THE
SOUTHEASTERN AND MID ATLANTIC STATES THROUGH FRIDAY.
AS THE RIDGE BUILDS AND A SHORTWAVE TROUGH OR TWO IN THE ZONAL FLOW
MOVES FROM THE CENTRAL PLAINS TOWARD THE LOWER OH VALLEY REGION AND
INTO THE MIDDLE OH VALLEY REGION...WHAT IS LEFT OF THE BOUNDARY AND
DEEPER MOISTURE SHOULD ALSO BEGIN TO RETREAT BACK INTO THE REGION BY
WED NIGHT INTO THU. THIS SHOULD LEAD TO AN ADDITIONAL PERIOD WHERE
CONVECTION IS POSSIBLE. THE MODEL CONSENSUS IS FOR THE RIDGE TO
BUILD IN BEHIND THIS SHORTWAVE FOR THU NIGHT AND INTO EARLY ON FRI.
OVERALL...CONVECTION FROM THU NIGHT INTO FRIDAY MAY HAVE SOMEWHAT OF
A DIURNAL FLAVOR.
ALSO DURING THIS TIME...A SERIES OF TROUGHS WILL TRAVERSE THE
NORTHERN STREAM AND SEND A COLD FRONT SOUTH INTO AND GRADUALLY ACROSS
THE THE LOWER OH VALLEY REGION AND EASTERN KENTUCKY THIS WEEKEND.
THIS WILL BRING PERIOD OF UNSETTLED WEATHER...WITH PROLONGED CHANCES
FOR SHOWERS AND THUNDERSTORMS FROM SATURDAY INTO SUNDAY.
TEMPERATURES ARE EXPECTED TO AVERAGE NEAR TO A FEW DEGREES ABOVE
NORMAL FROM WED INTO SATURDAY FOR DAYTIME HIGHS...WITH OVERNIGHT LOW
HAVING THE GREATER DEPARTURE OF NEARLY 5 DEGREES ON AVERAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 647 AM EDT MON SEP 1 2014
LOW CLOUDS HAVE DEVELOPED AND SPREAD ACROSS MUCH OF EASTERN KENTUCKY
THIS MORNING. FOR THE MOST PART...MVFR CIGS ARE BEING REPORTED.
HOWEVER...A FEW SPOTS IN THE NORTH MAY BE DOWN TO IFR CIGS. WE SHOULD
SEE GRADUAL IMPROVEMENT THROUGH THE MORNING HOURS BEFORE VFR
CONDITIONS RETURN BY MIDDAY. ISOLATED TO SCATTERED SHOWERS AND STORMS
STILL LOOK LIKE A POSSIBILITY THIS AFTERNOON...BUT NO ENOUGH COVERAGE
OR CONFIDENCE TO INCLUDE IN THE TAFS. VFR CONDITIONS LOOK TO CONTINUE
THROUGH TONIGHT WITH ONLY SOME VERY PATCHY VALLEY FOG. AT THIS
TIME...THIS IS NOT EXPECTED TO IMPACT THE TAF SITES TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM...JP
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
640 AM EDT Mon Sep 1 2014
...Updated Aviation Discussion...
.SHORT TERM (Now through Tuesday)...
Issued at 310 AM EDT Mon Sep 1 2014
A slow-moving cool front to our northwest will bring a noticeable
increase in southwesterly winds today, with gusts of 15 to 25 mph
likely this afternoon. First off though we may see some isolated
low-topped showers this morning, with convergence along a weak
low-level jet early this morning already initiating some in central
IN. HRRR indicates better coverage than what I`ll have in my
forecast, as current guidance coverage already is too high.
Cloud cover from the moist low levels and as additional moisture
streams into the region today in a deep southwesterly flow should
keep high temperatures from getting too far above normal, with
readings likely topping out in the mid to upper 80s. The focus for
storms this evening will be to our west and northwest, closer to the
approaching front. These storms may be able to get into our southern
Indiana counties around or after midnight.
There still are some uncertainties about how convective development
will occur from early to late Tuesday, as a lot will depend on the
evolution of these storms moving into our region. Should those
storms get in here more toward daybreak, then convective debris
could be enough to prevent furthern development during the day
Tuesday, despite relatively high precipitable waters. Should those
storms die off overnight and leave boundaries behind, Tuesday could
become more active with heating. Will leave in likely pops for the
day Tuesday, as would lean more towards the latter solution that
we`ll see a few breaks in the clouds to generate more storms.
.LONG TERM (Tuesday Night through Sunday)...
Issued at 305 AM EDT Mon Sep 01 2014
Tuesday Night and Wednesday...
Surface high pressure will slide over the Ohio Valley behind the
nearly washed out front to our south on Tuesday night. An isolated
shower or storm could linger into the evening hours across the south
or east CWA, otherwise expect a dry and slightly cooler night. Lows
should drop into the upper 60s and around 70. Isolated or widely
scattered diurnally driven showers/storms are expected to be
possible across southern KY on Wednesday. Most areas will stay dry
with mostly sunny skies and highs in the 85 to 88 degree range.
Wednesday Night - Friday...
The southern CONUS upper ridge will build over the area to end the
week, however this will not be enough to suppress diurnally
driven convection each afternoon and early evening. Will continue
mention of isolated to widely scattered coverage on Thursday, with
better coverage on Friday more solidly in the scattered range. Along
with this ridge, the heat and humidity will return with highs in the
upper 80s to around 90 each day. With dew points in the low 70s each
day, conditions will feel quite muggy. The environment should become
pretty unstable each afternoon/evening, however the lack of deep
layer flow will keep any convection pulse in nature. Lows by
Thursday night will be back in the low 70s.
Friday Night - Saturday Night...
The upper ridge will be suppressed southward to start the weekend, as
a wave skirts along the eastern US/Canada border. This will drag a
stronger cold front toward our moist and unstable airmass, keeping
scattered storms in play on Friday night. Saturday should bring the
best chance of storms for the whole forecast period as the front
tries to slide through. Have gone with 40-50% coverage. With
slightly better deep layer flow over the area, the threat for a few
stronger storms seems reasonable. Biggest concern would be gusty
winds, along with cloud to ground lightning and brief heavy
rainfall. A few storms could linger in our south and east Saturday
evening.
Expect more mild lows on Friday night with the mercury only dropping
to the low 70s. Highs on Saturday will be dependent on convection
and where the frontal boundary resides, but it looks like temps will
max out around 80 north, to the mid or upper 80s south. Lows
Saturday night will be cooler on the north side of the boundary.
Look for readings in the 60s.
Sunday...
Surface high pressure takes back over on Sunday, bringing dry and
cooler conditions to start the new work week. Look for highs in the
upper 70s and low 80s, with lows Sunday night expected to be in the
upper 50s and low 60s!
&&
.AVIATION (12Z TAF Update)...
Issued at 640 AM EDT Mon Sep 1 2014
Have a few light rain showers forming north of a KSDF/KLEX line this
hour, but even should the rain make the terminals it should be light
enough not to reduce visibility much. The bigger factor now is
ceilings, with them hovering between MVFR and IFR at those two
sites, and KBWG may see it soon too. These clouds will lift by mid
morning. An isolated storm still cannot be ruled out later this
afternoon, but again coverage too limited to put in TAFs at this
time. Should see more storms coming in early Tuesday, first at KSDF
as a cool front approaches the region.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Short Term........RJS
Long Term.........BJS
Aviation..........RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
315 AM EDT Mon Sep 1 2014
.SHORT TERM (Now through Tuesday)...
Issued at 310 AM EDT Mon Sep 1 2014
A slow-moving cool front to our northwest will bring a noticeable
increase in southwesterly winds today, with gusts of 15 to 25 mph
likely this afternoon. First off though we may see some isolated
low-topped showers this morning, with convergence along a weak
low-level jet early this morning already initiating some in central
IN. HRRR indicates better coverage than what I`ll have in my
forecast, as current guidance coverage already is too high.
Cloud cover from the moist low levels and as additional moisture
streams into the region today in a deep southwesterly flow should
keep high temperatures from getting too far above normal, with
readings likely topping out in the mid to upper 80s. The focus for
storms this evening will be to our west and northwest, closer to the
approaching front. These storms may be able to get into our southern
Indiana counties around or after midnight.
There still are some uncertainties about how convective development
will occur from early to late Tuesday, as a lot will depend on the
evolution of these storms moving into our region. Should those
storms get in here more toward daybreak, then convective debris
could be enough to prevent furthern development during the day
Tuesday, despite relatively high precipitable waters. Should those
storms die off overnight and leave boundaries behind, Tuesday could
become more active with heating. Will leave in likely pops for the
day Tuesday, as would lean more towards the latter solution that
we`ll see a few breaks in the clouds to generate more storms.
.LONG TERM (Tuesday Night through Sunday)...
Issued at 305 AM EDT Mon Sep 01 2014
Tuesday Night and Wednesday...
Surface high pressure will slide over the Ohio Valley behind the
nearly washed out front to our south on Tuesday night. An isolated
shower or storm could linger into the evening hours across the south
or east CWA, otherwise expect a dry and slightly cooler night. Lows
should drop into the upper 60s and around 70. Isolated or widely
scattered diurnally driven showers/storms are expected to be
possible across southern KY on Wednesday. Most areas will stay dry
with mostly sunny skies and highs in the 85 to 88 degree range.
Wednesday Night - Friday...
The southern CONUS upper ridge will build over the area to end the
week, however this will not be enough to suppress diurnally
driven convection each afternoon and early evening. Will continue
mention of isolated to widely scattered coverage on Thursday, with
better coverage on Friday more solidly in the scattered range. Along
with this ridge, the heat and humidity will return with highs in the
upper 80s to around 90 each day. With dew points in the low 70s each
day, conditions will feel quite muggy. The environment should become
pretty unstable each afternoon/evening, however the lack of deep
layer flow will keep any convection pulse in nature. Lows by
Thursday night will be back in the low 70s.
Friday Night - Saturday Night...
The upper ridge will be suppressed southward to start the weekend, as
a wave skirts along the eastern US/Canada border. This will drag a
stronger cold front toward our moist and unstable airmass, keeping
scattered storms in play on Friday night. Saturday should bring the
best chance of storms for the whole forecast period as the front
tries to slide through. Have gone with 40-50% coverage. With
slightly better deep layer flow over the area, the threat for a few
stronger storms seems reasonable. Biggest concern would be gusty
winds, along with cloud to ground lightning and brief heavy
rainfall. A few storms could linger in our south and east Saturday
evening.
Expect more mild lows on Friday night with the mercury only dropping
to the low 70s. Highs on Saturday will be dependent on convection
and where the frontal boundary resides, but it looks like temps will
max out around 80 north, to the mid or upper 80s south. Lows
Saturday night will be cooler on the north side of the boundary.
Look for readings in the 60s.
Sunday...
Surface high pressure takes back over on Sunday, bringing dry and
cooler conditions to start the new work week. Look for highs in the
upper 70s and low 80s, with lows Sunday night expected to be in the
upper 50s and low 60s!
&&
.AVIATION (06Z TAF Update)...
Issued at 120 AM EDT Mon Sep 1 2014
Have some mid-level drying out their now, helping to rid the region
of showers/storms for now, but not necessarily lower-level issues.
Each of the terminals may see some periods of MVFR clouds through
daybreak. Then we will see winds pick up from the southwest, ahead
of a cold front approaching from the northwest. Gusts of 20-25 knots
are possible through the day. An isolated pop-up storm is possible
in the afternoon, but not confident enough to put in the forecast at
this time. The better chance for rain will come Tuesday.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Short Term........RJS
Long Term.........BJS
Aviation..........RJS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
940 PM EDT TUE SEP 2 2014
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION LATE TONIGHT THROUGH EARLY
WEDNESDAY. HIGH PRESSURE WILL BUILD ACROSS THE REGION LATER
WEDNESDAY THROUGH THURSDAY. THE NEXT COLD FRONT WILL MOVE THROUGH
FRIDAY NIGHT.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
930 PM UPDATE: LATEST RADAR INDICATES THAT THE FIRST WAVE OF SHWRS
AND TSTMS HAS MOVED E ACROSS NRN PTNS OF THE FA AS OF MID EVE. ONE
NARROW BAND OF TSTMS OVR CNTRL AND NRN PTNS OF PISCATAQUIS COUNTY
NORTHEAST OF THE N END OF MOOSEHEAD LK MAY BE RESULTING IN LCLZD
STREAM FLOODING IN THIS AREA. OTHERWISE RNFL HAS BEEN LGT. BOTH
3-6 HR SYNOPTIC AND HRRR (HRLY) GUIDANCE SUGGESTS MORE GENERAL
RNFL MOVG ACROSS ALL OF THE FA LATER TNGT...WITH THE BEST
POTENTIAL OF ELEVATED CNVCTN RE-ALIGNING OVR WSW AND DOWNEAST
PTNS OF THE FA WHERE MUCAPES WILL REMAIN NEAR 1000 J/KG WELL INTO
THE LATE NGT.
OTHERWISE...WE INCREASED CVRG OF FOG OVRNGT ACROSS THE SRN HLF OF
THE FA BASED ON LATEST OBS ALREADY SHOWING MORE DENSE FOG THERE.
OTHERWISE...HRLY FCST TEMPS TO POSTED OVRNGT LOWS AT 5 TO 6 AM
WERE MODIFIED SLGTLY BASED ON TRENDS FROM 9 PM OBS FROM THE PREV
FCST OF TEMPS AT 9 PM.
ORGNL DISC: THE AREA IS CURRENTLY IN A HUMID AIRMASS AHEAD OF A
COLD FRONT WITH LINGERING LOW CLOUDS DOWNEAST. THERE HAVE BEEN
SOME SHOWERS ACROSS THE NORTH THIS AFTERNOON HOWEVER WE EXPECT
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS TO OCCUR TONIGHT WITH
THE ACTUAL COLD FRONTAL PASSAGE. SHOWERS/STORMS WILL ARRIVE THIS
EVENING IN THE NORTH AND WEST AND REACH DOWNEAST AREAS OVERNIGHT.
FORECAST MODELS DO DEPICT CAPES OF 500 TO 1000 K/KG ACROSS THE
NORTH AND WEST BUT THIS BECOME MAINLY ELEVATED CAPE AND LAPSE
RATES ARE NOT PARTICULARLY IMPRESSIVE. FOR THIS REASON DO NOT SEE
A HIGH THREAT FOR SEVERE WEATHER BUT WITH PWATS OF 1.5 TO 2.0
INCHES ALONG WITH A DEEP WARM CLOUD LAYER THERE WILL BE THE
POTENTIAL FOR SOME HEAVY RAIN WITH THESE STORMS...ESPECIALLY IN
THE NORTH THIS EVENING SO DID ADD THE ENHANCED WORDING OF HEAVY
RAIN TO THE N/W ZONES THROUGH THE EVENING. ALSO EXPECT SOME FOG TO
DEVELOP ONCE AGAIN OVERNIGHT.
THE FRONT WILL CLEAR EASTERN AREAS EARLY WEDNESDAY MORNING WITH
ANY LEFT OVER SHOWERS ENDING. THE REMAINDER OF THE DAY WILL
FEATURE MAINLY SUNNY SKIES IN THE SOUTH WITH A MIX OF SUN AND
CLOUDS NORTH WITH THE CHANCE OF SOME SCATTERED SHOWERS ONCE AGAIN
BY AFTERNOON AS A WEAK DISTURBANCE MOVES THROUGH. HIGHS WILL BE IN
THE 70S TO AROUND 80 WITH LOWER HUMIDITY.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT, HIGH PRESSURE WILL BE
POSITIONED JUST SOUTH OF THE GULF OF MAINE. WITH US BEING JUST
NORTH OF THE HIGH, LOOK FOR STABLE WESTERLY FLOW WITH DRY
CONDITIONS AND GENERALLY MOSTLY CLEAR SKIES.
ON FRIDAY, THE HIGH MOVES EAST FURTHER OUT INTO THE NORTH ATLANTIC,
AND A COLD FRONT BEGINS TO APPROACH FROM THE WEST. THIS WILL LEAD
TO A SOUTHERLY BREEZE AND MUGGIER AIRMASS. CLOUDS WILL INCREASE
THROUGH THE DAY FRIDAY, BUT IT APPEARS PRECIP CHANCES WILL HOLD
OFF UNTIL FRIDAY EVENING FOR MOST PLACES EXCEPT PERHAPS FAR
NORTH/NORTHWEST MAINE.
MODELS ARE IN GOOD AGREEMENT THROUGH FRIDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A COLD FRONT WILL MOVE THROUGH FROM NORTHWEST TO SOUTHEAST FRIDAY
NIGHT, WITH SHOWERS AND STORMS POSSIBLE. HIGH PRESSURE AND COOLER
AIR BUILD IN FROM THE NORTH FOR SATURDAY AND SUNDAY, ALTHOUGH
THERE IS SOME QUESTION AS TO HOW QUICKLY THE FRONT CAN CLEAR
DOWNEAST MAINE. BUT GENERALLY, IMPROVING WEATHER FROM NORTH TO
SOUTH ON THE WEEKEND, WITH VERY LIKELY THAT EVEN DOWNEAST WILL BE
DRY FOR SUNDAY.
ANOTHER WEAK COLD FRONT IS EXPECTED TO PASS THROUGH AROUND SUNDAY
NIGHT OR MONDAY, WITH THE FRONT PROBABLY LACKING ANY
PRECIPITATION. THIS WILL KEEP TEMPERATURES NEAR OR A BIT BELOW
AVERAGE INTO EARLY NEXT WEEK. IF WE HAVE A NIGHT WHERE HIGH
PRESSURE SETS UP JUST RIGHT, THERE COULD BE SOME FROST IN MORE
PROTECTED VALLEYS.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
NEAR TERM: EXPECT CONDITIONS TO DETERIORATE ONCE AGAIN TONIGHT AS
SHOWERS AND POTENTIAL THUNDERSTORMS MOVE IN WITH A COLD FRONT AND
LOW STRATUS AND FOG BECOMES AN ISSUE ALONG THE COAST. EXPECT IFR
ONCE AGAIN BY THE OVERNIGHT IN THE NORTH WITH LIFR FOR THE SOUTHERN
SITES. CONDITIONS IMPROVE TO VFR THROUGH WEDNESDAY MORNING BEHIND
THE FRONT.
SHORT TERM: VFR EXPECTED WEDNESDAY NIGHT THROUGH FRIDAY, WITH THE
POSSIBLE EXCEPTION OF PATCHY FOG EARLY THURSDAY MORNING. MVFR AND
IFR POSSIBLE FRIDAY NIGHT AS A COLD FRONT PASSES THROUGH, THEN
IMPROVING TO VFR FOR MOST AREAS BY LATE SATURDAY, WITH VFR
CONTINUING INTO EARLY NEXT WEEK.
&&
.MARINE...
NEAR TERM: FOG WILL CONTINUE TO BE AN ISSUE THROUGH TONIGHT WITH
SOME SHOWERS AND THUNDERSTORMS ALSO MOVING THROUGH TONIGHT WITH A
COLD FRONT. HOWEVER WINDS/SEAS REMAIN BELOW SCA LEVELS. CONDITIONS
CLEAR WEDNESDAY WITH WEST WINDS BEHIND THE FRONT.
SHORT TERM: SUB SMALL CRAFT WINDS AND SEAS WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. AS A COLD FRONT APPROACHES FRIDAY, SOUTH WINDS AND
SEAS WILL BEGIN TO INCREASE, WITH BOTH POSSIBLY REACHING SMALL
CRAFT LEVELS LATE FRIDAY AFTERNOON AND PERSISTING THROUGH FRIDAY
NIGHT, BEFORE CONDITIONS IMPROVE FOR SATURDAY AND SUNDAY BACK TO
SUB SMALL CRAFT LEVELS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...VJN
SHORT TERM...FOISY
LONG TERM...FOISY
AVIATION...VJN/FOISY
MARINE...VJN/FOISY
AREA FORECAST DISCUSSION
NWS GRAY ME
1240 AM EDT MON SEP 1 2014
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTHEAST THROUGH THE REGION O0VERNIGHT
AND WILL STALL OFF THE COAST ON MONDAY. A SECOND COLD FRONT WILL
APPROACH FROM THE WEST ON TUESDAY AND WILL CROSS THE REGION
TUESDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE WEST ON
WEDNESDAY AND WILL CREST OVER THE REGION THURSDAY BEFORE SHIFTING
OFFSHORE. HIGH PRESSURE WILL HOLD OFF THE NEW ENGLAND COAST ON
FRIDAY. A COLD FRONT WILL CROSS THE AREA ON SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATE...
HAVE UPDATED THE GRIDS BASED ON CURRENT CONDITIONS. SOAKING RAINS
IN THE PORTLAND AREA HAVE SHIFTED EAST AND INTO THE GULF OF MAINE
EARLY THIS MORNING. IN ITS WAKE...PLENTY OF FOG WILL DEVELOP WITH
LOW LEVEL MOISTURE IN PLACE AND CLEARING SKIES. MODIFIED CLOUD AND
DEW POINT GRIDS...OTHERWISE...NO SIGNIFICANT CHANGES THIS HOUR.
PREV DISC...
SHOWERS AND EMBEDDED TSTMS CONTINUE TO SLOWLY MOVE EWD ACROSS THE
SRN PART OF THE FORECAST AREA. IN A LINE FROM JUST E OF KCON TO
KPWM RAIN IS HEAVY AT TIMES...WITH OCNL RATES IN EXCESS OF 3
INCHES/HR. BACK EDGE IS QUICKLY APPROACHING THE COAST...THOUGH
HEAVIEST RATES WILL LINGER WITHIN THIS LINE. TO EITHER SIDE OF
THAT LINE...A LIGHTER RAIN WILL CONTINUE TO FALL FOR THE NEXT
COUPLE OF HOURS. HAVE ADJUSTED POP BASED ON RADAR TREND AND LATEST
HI-RES MODEL GUIDANCE. SHOULD BE A MOSTLY DRY NIGHT ONCE THIS RNFL
CLEARS THE COAST...EXCEPT FOR THE FAR NRN ZONES WHERE LINGERING
CONVECTION ASSOCIATED WITH LEADING EDGE OF S/WV TROF MAY HOLD
TOGETHER.
PREVIOUS DISCUSSION...A SHORT WAVE TROUGH APPROACHING FROM THE
WEST WILL WEAKEN THIS EVENING AS IT MOVES EASTWARD TOWARD NORTHERN
NEW ENGLAND. THE ATTENDANT SFC COLD FRONT WILL APPROACH AS
WELL...AND ALSO WEAKEN. A SHIELD OF LIGHT RAIN CONTINUES TO
TRAVERSE ACROSS NORTHERN AND CENTRAL ZONES AS OF 19Z THIS SUNDAY
AFTERNOON. THIS WILL STABILIZE THE AIRMASS ACROSS THIS AREA.
HOWEVER...ALONG THE COASTAL PLAIN SWWD OVER TO SOUTHERNMOST NH
SHOULD REMAIN MOSTLY DRY FOR THE NEXT SEVERAL HOURS.
THEREFORE...THESE AREAS SHOULD RETAIN THE INSTABILITY /1000-1500
J/KG SBCAPE/ THROUGH EARLY EVENING. THE QUESTION IS DO
THUNDERSTORMS DEVELOP IN THIS AREA.
SEVERAL OF THE LATEST RUNS OF THE HRRR CONTINUE TO SHOW
THUNDERSTORMS WILL HEAVY RAINFALL MOVING ACROSS SOUTHERNMOST NH
AND SOUTHERNMOST ME BETWEEN 22Z AND 03Z. THIS SEEMS REASONABLE
GIVEN THE CURRENT MESOSCALE SETUP. AS A RESULT WILL CONTINUE WITH
HIGH POPS...ESPECIALLY IN THIS AREA. MODERATE DEEP LAYER SHEAR MAY
AID IN A FEW OF THESE STORMS BECOMING STRONG...WITH GUSTY WINDS
BEING THE MAIN THREAT. WITH PWATS INCREASING TO AROUND 2 INCHES BY
EARLY EVENING...TORRENTIAL DOWNPOURS WILL BE LIKELY IN ANY
THUNDERSTORM. THERE IS A LOW PROB FOR TRAINING STORMS ACROSS
SOUTHERN NH AND SOUTHERNMOST ME...SO LOCALIZED FLASH FLOODING WILL
BE POSSIBLE THIS EVENING. THE BULK OF THE ACTIVITY SHOULD MOVE
OFFSHORE AROUND MIDNIGHT LEADING TO A MAINLY DRY OVERNIGHT.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM TUESDAY/...
ON MONDAY...THE SHORT WAVE TROUGH WILL DEPART IN THE MORNING.
STILL...WITH MODERATE AMOUNTS OF LOW LEVEL THETA-E IN TANDEM WITH
SLIGHTLY COOLER TEMPS ALOFT AND A WEAK SFC FRONT IN THE VCNTY...WE
COULD SEE A FEW SHOWERS DURING THE DAY...PERHAPS A THUNDERSTORM.
HOWEVER...ACTIVITY SHOULD BE FEW AND FAR BETWEEN...WITH HIGHEST
POPS ACROSS CENTRAL AND NORTHERN ZONES. HUMID CONDITIONS WILL
CONTINUE.
MUGGY AND QUIET MONDAY NIGHT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
COLD FRONT APPROACHES FROM THE WEST ON TUESDAY AND WILL
SET THE STAGE FOR POSSIBLE SEVERE WEATHER. PRE-FRONTAL
TROUGH FORECAST TO PUSH IN FROM THE WEST DURING PRIME TIME
HEATING. MODERATE CAPES AND INCREASING SHEAR DURING THE
AFTERNOON AND EVENING HOURS WILL LIKELY RESULT IN MORE
ORGANIZED CONVECTION DURING THE LATE AFTERNOON AND EVENING WITH
DAMAGING WINDS THE MAIN THREAT. STRONGER CELLS MAY ALSO PRODUCE
SOME HAIL BUT FREEZING LEVELS WILL BE QUITE HIGH SO NOT LOOKING
FOR MUCH IN THE WAY OF SEVERE HAIL. WILL SEE A HOT AND MUGGY DAY
WITH HIGHS RANGING THROUGH THE 80S.
COLD FRONT WILL PUSH OFFSHORE TUESDAY NIGHT WITH CONVECTION ENDING
ACROSS THE REGION BY MIDNIGHT. HIGH PRESSURE BUILDING IN FROM THE
WEST WILL BRING CLEARING DOWNWIND OF THE MOUNTAINS. LOW TEMPS
OVERNIGHT WILL RANGE THROUGH THE 60S.
COOLER AND MUCH DRIER AIR PUSHES IN FOR WEDNESDAY AS HIGH PRESSURE
CONTINUES TO BUILD INTO THE NORTHEAST. SHOULD SEE A MOSTLY SUNNY
DAY WITH HIGHS FROM THE MID 70S TO LOWER 80S.
FAIR WEATHER WILL CONTINUE THURSDAY AND FRIDAY AS HIGH PRESSURE
CONTINUES TO BUILD SOUTH OF THE REGION FINALLY PUSHING OFFSHORE
ON FRIDAY. AFTER A STELLAR LATE SUMMER DAY ON THURSDAY...RETURN
FLOW WILL BEGIN TO PUMP WARMER AND MORE HUMID AIR BACK INTO THE
REGION ON FRIDAY. MAY SEE ENOUGH INSTABILITY CREEP INTO THE
CONNECTICUT VALLEY LATE FRIDAY TO KICK OFF AN ISOLATED SHOWER OR
THUNDERSTORM BUT THE MAJORITY OF THE FORECAST AREA WILL SEE A DRY
DAY.
RATHER STRONG LOOKING COLD FRONT FORECAST TO PUSH IN FROM THE WEST
ON SATURDAY WHICH COULD PRODUCE ANOTHER ROUND OF SEVERE
THUNDERSTORMS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
.SHORT TERM...LOCAL IFR IN SHOWERS AND THUNDERSTORMS THIS
EVENING. AFTER MIDNIGHT...FOG AND SOME LOW STRATUS MAY DEVELOP AND
RESULT IN LOW CONDITIONS AS WELL. MAINLY VFR EXPECTED ON MONDAY
OUTSIDE OF WDLY SCT SHOWERS.
.LONG TERM...MAINLY VFR EXPECTED OUTSIDE OF ANY SHOWERS AND
THUNDERSTORMS TUE EVE/NIGHT. SOME VALLEY FOG AND COASTAL STRATUS
POSSIBLE DURING THE PERIOD LATE AT NIGHT.
&&
.MARINE...
.SHORT TERM...HAVE DROPPED THE SCAS FOR TONIGHT.
.LONG TERM...SUB-SCA EXPECTED TUE THROUGH FRI.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
658 PM EDT MON SEP 1 2014
.AVIATION...
//DISCUSSION...
CONVECTION WILL BE ENDING AT THE BEGINNING OF THE FORECAST PERIOD
EVEN AS SURFACE TROUGH IS LAGGING WELL TO THE WEST. LIGHT SOUTHWEST
FLOW IN ADVANCE OF THIS FEATURE WILL MAINTAIN ABUNDANT LOW LEVEL
MOISTURE INTO TONIGHT WITH PATCHY/AREAS OF FOG AND STRATUS AGAIN
LATE TONIGHT INTO TUESDAY MORNING. DRIER AIR THEN MIXES INTO THE
AREA FROM MID/LATE MORNING TUESDAY ON INTO THE AFTERNOON WITH VFR
CONDITIONS EXPECTED WITH TIME.
FOR DTW...REMAINING SHRAS WITH PERHAPS A RUMBLE OF THUNDER WILL BE
MOVING EAST AND SOUTHEAST OF THE TERMINAL AS THIS FORECAST PERIOD
BEGINS. OTHERWISE...PATCHY FOG/STRATUS WILL BE POSSIBLE IN THE 07Z
TO 14Z TIME FRAME.
//DTW THRESHOLD THREATS...
* LOW CONFIDENCE THAT A THUNDERSTORM WILL IMPACT THE TERMINAL THRU
01Z THIS EVENING.
* LOW CONFIDENCE IN CEILINGS BELOW 5000 FEET LATE TONIGHT INTO EARLY
TUESDAY.
&&
.PREV DISCUSSION...ISSUED 244 PM EDT MON SEP 1 2014
SHORT TERM...THIS EVENING AND TONIGHT
18Z SPECIAL CONFIRMS THE WARMER COLUMN DEPICTED BY THE RAP AND THEN
SOME. 900MB INVERSION IS QUITE A BIT MORE ROBUST THAN DEPICTED BY
THE GUIDANCE AS IS THE 600MB CAP. THUS, EVEN THE MOST TAME
DEPICTIONS OF CONVECTION IN THE NWP ARE LIKELY TOO AGGRESSIVE AND
CONCERNS REGARDING CAPPING NOTED IN THE MORNING UPDATE ARE
CONFIRMED. UPDRAFTS WILL STRUGGLE ACROSS MOST OF THE CWA WITH THE
EXCEPTION OF LOCATIONS NORTH OF I-69 AND ESPECIALLY WEST OF US-23
WHERE MID-LEVEL COOLING AND FORCING WILL BE MAXIMIZED. WITH THE LINE
ALREADY MARCHING TOWARD THIS AREA, EXPECT THAT THE ABUNDANCE OF
MID-LEVEL DRY AIR AND UNIDIRECTIONAL FLOW ABOVE 1.5KM WILL SUPPORT
BOWING SEGMENTS CARRYING A LOW-END SEVERE WIND THREAT. IN ADDITION,
ISOLATED TORNADO THREAT OUTLINED IN THE EARLIER UPDATE REMAINS IN
TACT. FOR REMAINING AREAS, EXPECT NOTHING MORE THAN A GUST TO 40
MPH. IN ADDITION, BACKED OFF ON POPS AS EARLIER SUSPICIONS REGARDING
COVERAGE POTENTIAL STILL LOOM.
A WEAK COLD FRONT WILL SAG THROUGH THE AREA TONIGHT. FRONTAL
INVERSION WILL PROMOTE EXPANSION OF STRATUS LATE TONIGHT, BUT EXPECT
THAT MOISTURE WILL BE TOO SHALLOW AND FORCING TOO WEAK TO SUPPORT
ANY LEGITIMATE COVERAGE OR INTENSITY OF SHOWERS. WITH UPPER SUPPORT
IN THE FORM OF A SHEARING SHORTWAVE NOT SCHEDULED TO ARRIVE UNTIL
TUESDAY MORNING PER 12Z GUIDANCE, AND MAINLY SOUTH OF THE AREA AT
THAT, NOTHING MORE THAN A CHC POP IS WARRANTED ATTM.
LONG TERM...TUESDAY THROUGH NEXT MONDAY
A COLD FRONT WILL BE SOUTHEAST OF THE CWA TO START OUT TUESDAY
MORNING. HOWEVER A MID LEVEL SHORTWAVE RIDING NORTHEAST ALONG THE
FRONT WILL BRING THE CHANCE FOR SHOWERS AND THUNDERSTORMS TO THE
AREA TUESDAY MORNING. AFTER THE SHORTWAVE TRACKS OFF TO THE
NORTHEAST SIGNIFICANT DRYING WILL TAKE PLACE AS A SLUG OF 30 PERCENT
RELATIVE HUMIDITY AT 700 MB ADVECTS IN FROM THE WEST...ENDING RAIN
CHANCES QUICKLY EARLY TUESDAY AFTERNOON. WHILE THERE IS STILL SOME
UNCERTAINTY REGARDING HOW FAR WEST THE RAIN WILL FALL GIVEN THE PUSH
OF DRY AIR ADVECTING IN...THE LATEST SUITE OF MODELS HAS THE DRIER
AIR PUSHING IN A BIT SOONER THAN THE 00Z RUNS. THEREFORE WILL NUDGE
THE FORECAST A BIT DRIER TUESDAY AFTERNOON FROM THE PREVIOUS
FORECAST. DESPITE THE PASSAGE OF A COLD FRONT THERE ISN`T A LARGE
PUSH OF COLD AIR ASSOCIATED WITH IT...MEANING DAYTIME HIGHS ARE
EXPECTED TO GET AROUND 80 TUESDAY AFTERNOON BEHIND THE FRONT.
RIDGING WILL KEEP THE FORECAST DRY THROUGH WEDNESDAY AS REBOUNDING
HEIGHTS ALLOW DAYTIME HIGHS TO GET BACK INTO THE LOWER 80S BY
WEDNESDAY AFTERNOON.
MOISTURE SURGE FROM THE GULF OF MEXICO COMMENCES ON THURSDAY AS A
LOW CHANCE FOR CONVECTION EXISTS WITHIN THE WARM SECTOR OF A
REGION-WIDE LOW PRESSURE SYSTEM. BEST CHANCE FOR THUNDERSTORMS
/POSSIBLY SEVERE/ WILL BE FRIDAY AS WARM AND MOIST AIRMASS (85/70
T/TD) IS IN PLACE ALONG WITH FORECASTED CAPE OF 3000 J/KG. BULK
SHEAR INCREASES TO NEAR 30 KT IN THE 1-6 KM LAYER AS WELL. THESE
INGREDIENTS WILL BE IN PLACE AS A RAGGED COLD FRONT CROSSES THE
STATE. THIS BRINGS A TRIPLE THREAT OF SEVERE WEATHER WITH
WIND...HAIL...AND ISOLATED TORNADOES ALL POSSIBLE
MARINE...
SHOWERS AND THUNDERSTORMS WILL TRACK THROUGH THE CENTRAL GREAT LAKES
TONIGHT AS A COLD FRONT MOVES THROUGH LAKE HURON AND LOWER MICHIGAN.
SOME OF THESE STORMS MAY BE SEVERE...MAINLY ACROSS THE NORTHERN
PORTION OF LAKE HURON. HIGH PRESSURE WILL BUILD INTO THE REGION
BEHIND THIS FRONT ON TUESDAY...WHICH WILL REMAIN IN CONTROL OF THE
WEATHER THROUGH THURSDAY...PROVIDING FAVORABLE BOATING CONDITIONS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....99
SHORT TERM...JVC
LONG TERM....KURIMSKI/MM
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
244 PM EDT MON SEP 1 2014
.SHORT TERM...THIS EVENING AND TONIGHT
18Z SPECIAL CONFIRMS THE WARMER COLUMN DEPICTED BY THE RAP AND THEN
SOME. 900MB INVERSION IS QUITE A BIT MORE ROBUST THAN DEPICTED BY
THE GUIDANCE AS IS THE 600MB CAP. THUS, EVEN THE MOST TAME
DEPICTIONS OF CONVECTION IN THE NWP ARE LIKELY TOO AGGRESSIVE AND
CONCERNS REGARDING CAPPING NOTED IN THE MORNING UPDATE ARE
CONFIRMED. UPDRAFTS WILL STRUGGLE ACROSS MOST OF THE CWA WITH THE
EXCEPTION OF LOCATIONS NORTH OF I-69 AND ESPECIALLY WEST OF US-23
WHERE MID-LEVEL COOLING AND FORCING WILL BE MAXIMIZED. WITH THE LINE
ALREADY MARCHING TOWARD THIS AREA, EXPECT THAT THE ABUNDANCE OF
MID-LEVEL DRY AIR AND UNIDIRECTIONAL FLOW ABOVE 1.5KM WILL SUPPORT
BOWING SEGMENTS CARRYING A LOW-END SEVERE WIND THREAT. IN ADDITION,
ISOLATED TORNADO THREAT OUTLINED IN THE EARLIER UPDATE REMAINS IN
TACT. FOR REMAINING AREAS, EXPECT NOTHING MORE THAN A GUST TO 40
MPH. IN ADDITION, BACKED OFF ON POPS AS EARLIER SUSPICIONS REGARDING
COVERAGE POTENTIAL STILL LOOM.
A WEAK COLD FRONT WILL SAG THROUGH THE AREA TONIGHT. FRONTAL
INVERSION WILL PROMOTE EXPANSION OF STRATUS LATE TONIGHT, BUT EXPECT
THAT MOISTURE WILL BE TOO SHALLOW AND FORCING TOO WEAK TO SUPPORT
ANY LEGITIMATE COVERAGE OR INTENSITY OF SHOWERS. WITH UPPER SUPPORT
IN THE FORM OF A SHEARING SHORTWAVE NOT SCHEDULED TO ARRIVE UNTIL
TUESDAY MORNING PER 12Z GUIDANCE, AND MAINLY SOUTH OF THE AREA AT
THAT, NOTHING MORE THAN A CHC POP IS WARRANTED ATTM.
&&
.LONG TERM...TUESDAY THROUGH NEXT MONDAY
A COLD FRONT WILL BE SOUTHEAST OF THE CWA TO START OUT TUESDAY
MORNING. HOWEVER A MID LEVEL SHORTWAVE RIDING NORTHEAST ALONG THE
FRONT WILL BRING THE CHANCE FOR SHOWERS AND THUNDERSTORMS TO THE
AREA TUESDAY MORNING. AFTER THE SHORTWAVE TRACKS OFF TO THE
NORTHEAST SIGNIFICANT DRYING WILL TAKE PLACE AS A SLUG OF 30 PERCENT
RELATIVE HUMIDITY AT 700 MB ADVECTS IN FROM THE WEST...ENDING RAIN
CHANCES QUICKLY EARLY TUESDAY AFTERNOON. WHILE THERE IS STILL SOME
UNCERTAINTY REGARDING HOW FAR WEST THE RAIN WILL FALL GIVEN THE PUSH
OF DRY AIR ADVECTING IN...THE LATEST SUITE OF MODELS HAS THE DRIER
AIR PUSHING IN A BIT SOONER THAN THE 00Z RUNS. THEREFORE WILL NUDGE
THE FORECAST A BIT DRIER TUESDAY AFTERNOON FROM THE PREVIOUS
FORECAST. DESPITE THE PASSAGE OF A COLD FRONT THERE ISN`T A LARGE
PUSH OF COLD AIR ASSOCIATED WITH IT...MEANING DAYTIME HIGHS ARE
EXPECTED TO GET AROUND 80 TUESDAY AFTERNOON BEHIND THE FRONT.
RIDGING WILL KEEP THE FORECAST DRY THROUGH WEDNESDAY AS REBOUNDING
HEIGHTS ALLOW DAYTIME HIGHS TO GET BACK INTO THE LOWER 80S BY
WEDNESDAY AFTERNOON.
MOISTURE SURGE FROM THE GULF OF MEXICO COMMENCES ON THURSDAY AS A
LOW CHANCE FOR CONVECTION EXISTS WITHIN THE WARM SECTOR OF A
REGION-WIDE LOW PRESSURE SYSTEM. BEST CHANCE FOR THUNDERSTORMS
/POSSIBLY SEVERE/ WILL BE FRIDAY AS WARM AND MOIST AIRMASS (85/70
T/TD) IS IN PLACE ALONG WITH FORECASTED CAPE OF 3000 J/KG. BULK
SHEAR INCREASES TO NEAR 30 KT IN THE 1-6 KM LAYER AS WELL. THESE
INGREDIENTS WILL BE IN PLACE AS A RAGGED COLD FRONT CROSSES THE
STATE. THIS BRINGS A TRIPLE THREAT OF SEVERE WEATHER WITH
WIND...HAIL...AND ISOLATED TORNADOES ALL POSSIBLE
&&
.MARINE...
SHOWERS AND THUNDERSTORMS WILL TRACK THROUGH THE CENTRAL GREAT LAKES
TONIGHT AS A COLD FRONT MOVES THROUGH LAKE HURON AND LOWER MICHIGAN.
SOME OF THESE STORMS MAY BE SEVERE...MAINLY ACROSS THE NORTHERN
PORTION OF LAKE HURON. HIGH PRESSURE WILL BUILD INTO THE REGION
BEHIND THIS FRONT ON TUESDAY...WHICH WILL REMAIN IN CONTROL OF THE
WEATHER THROUGH THURSDAY...PROVIDING FAVORABLE BOATING CONDITIONS.
&&
.AVIATION...ISSUED 114 PM EDT MON SEP 1 2014
//DISCUSSION...
LOW STRATUS CONTINUES TO MIX UP TO LOW VFR DIURNALLY FORCED CU.
EXPECT THIS TREND TO CONTINUE THROUGH THE NEAR TERM. ATTENTION
THEN TURNS TOWARD TSTORM CHANCES THIS AFTERNOON. CAPPING WILL
LIMIT POTENTIAL SOUTH OF KPTK SO TSHRA WAS REMOVED FOR THESE
LOCATIONS AS THE PROBABILITY IS NOW TOO LOW TO WARRANT A MENTION
IN THE TAFS. EXPECTATIONS REMAIN UNCHANGED FROM KFNT NORTH
UPSTREAM ACTIVITY IS MORE CERTAIN TO MOVE IN THIS AFTERNOON. LOW CLOUDS AND
PERHAPS A VISIBILITY RESTRICTION WILL BE POSSIBLE BEHIND THE FRONT
LATE TONIGHT BUT ONCE AGAIN EXPECT PRECIP POTENTIAL TO REMAIN
RATHER LOW WITH THE BULK OF 12Z GUIDANCE HOLDING ACTIVITY SOUTH OF
THE MICHIGAN BORDER.
FOR DTW...ALTHOUGH CONFIDENCE IN TSTORMS HAS DECREASED...IT AT LEAST
REMAINS PLAUSIBLE. THE BEST TIME FOR A THUNDERSTORM TO IMPACT THE
AIRPORT WILL BE 21Z-23Z THIS AFTERNOON. CONFIDENCE IN SHOWER
COVERAGE TOWARD MORNING IS ALSO QUITE LOW. ELECTED TO ELIMINATE
SPECIFIC MENTION FROM THE TAF UNTIL POTENTIALLY IMPACTED AREA BECOMES
MORE CLEAR.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILINGS BELOW 5KFT THIS AFTERNOON AND LATE TONIGHT
* LOW CONFIDENCE THAT A TSTORM WILL IMPACT KDTW
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...JVC
LONG TERM....KURIMSKI/MM
MARINE.......KURIMSKI
AVIATION.....JVC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
127 PM EDT MON SEP 1 2014
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 AM EDT MON SEP 1 2014
A COLD FRONT WILL MOVE INTO THE GREAT LAKES REGION FROM THE WEST
LATER TODAY AND INTO TONIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED
TO DEVELOP OVER SOUTHWEST LOWER MICHIGAN FROM THE LATE MORNING HOURS
PERSISTING INTO THE EVENING. SOME OF THE STORMS FROM THE MIDDAY
HOURS THROUGH THE EVENING MAY BE SEVERE WITH LARGE HAIL AND STRONG
WINDS. SHOWERS AND STORMS WILL GRADUALLY TAPER OFF TONIGHT
FROM NORTH TO SOUTH AS THE FRONT DROPS SOUTHWARD INTO INDIANA. DRY
WEATHER IS THEN EXPECTED FOR THE MOST PART FROM TUESDAY THROUGH
WEDNESDAY. CHANCES FOR SHOWERS AND STORMS INCREASE ONCE AGAIN
WEDNESDAY NIGHT THROUGH FRIDAY AS A LOW PRESSURE SYSTEM TRAVERSES
THE AREA. TEMPERATURES THIS WEEK WILL BE NEAR TO ABOVE NORMAL WITH
HIGHS IN THE UPPER 70S TO 80S ALL WEEK. A COOL DOWN IS EXPECTED NEXT
WEEKEND BEHIND A COLD FRONT THAT MOVES THROUGH ON FRIDAY.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 1100 AM EDT MON SEP 1 2014
ISOLATED SEVERE WEATHER THREAT CONTINUES THIS AFTERNOON (2PM - 8PM)
EAST OF U.S. 131 WITH DAMAGING WIND GUSTS THE MAIN THREAT. BRIEF
LOCALIZED FLOODING TYPICAL OF STRONG THUNDERSTORMS IS ALSO POSSIBLE.
APPROACHING WEAK FRONTAL BOUNDARY...SEPARATING DEWPOINTS IN THE LOW
70S FROM THOSE IN THE MID 60S...IS CURRENTLY ORIENTED NORTH-SOUTH
ACROSS EASTERN WISCONSIN AND ILLINOIS. THERE IS ALSO CONSIDERABLE
CLOUDINESS ALONG AND AHEAD OF FRONT WHICH IS TEMPERATURES AND
DESTABILIZATION OFTHE AIRMASS.
THE FRONT WILL SWEEP EASTWARD ACROSS THE CWA THIS AFTERNOON AND
EARLY EVENING PROVIDING LOW LEVEL LIFT AND POTENTIAL FOCUS FOR
DEVELOPMENT OF NEW STORMS. ALOFT HOWEVER...THE LEAD SHORTWAVE AND
NOSE OF UPPER JET WILL PUSH EASTWARD OVER THE REGION WITH BEST DEEP
LIFT NORTH MAINLY NORTH OF THE AREA.
INSTABILITY AND WIND FIELDS ARE FAVORABLE FOR SEVERE STORMS WITH
CAPE VALUES OF 500 - 1500 J/KG...0-6 KM BULK SHEAR VALUES NEAR 40
KTS...AND 0-1KM SHEAR VALUES AROUND 20 KTS. HOWEVER...LACK OF DEEP
LIFT WILL LIMIT COVERAGE OF STORMS AND OVERALL SEVERE THEAT
SIGNICANTLY. THIS SOLUTION IS REFLECTED IN MANY OF THE HIGHER
RESOLUTION CONVECTION ALLOWING MODELS INCLUDING LAST FEW NSSL WRF
AND HRRR RUNS.
OTHERWISE...THE SHORT TERM IS RELATIVELY QUIET. ANY STORMS THIS
EVENING SHOULD WORK SOUTH OF THE AREA OVERNIGHT. NOT OUT OF THE
REALM OF POSSIBILITIES FOR A FEW SHOWERS ON TUESDAY...BUT FELT THE
THREAT WAS SMALL ENOUGH TO GO DRY. TUESDAY NIGHT AND WEDNESDAY
SHOULD BE DRY WITH RIDGING IN PLACE AT THE SURFACE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM EDT MON SEP 1 2014
THE MOST UNSETTLED WEATHER IN THE LONG TERM LOOKS TO OCCUR IN THE
FIRST COUPLE OF DAYS...FROM THE BEGINNING OF THE PERIOD WED NIGHT
INTO FRI NIGHT. THE LATEST TREND IS FOR A LITTLE MORE POSSIBLE PCPN
WED NIGHT INTO THU WITH THE PASSAGE OF THE WARM FRONT THROUGH THE
AREA. THIS LOOKS TO BE THE CASE DUE TO THE GRADIENT/LOW LEVEL JET
EXPECTED TO BE A LITTLE STRONGER WITH A STRONGER TROUGH MOVING IN.
HOW QUICKLY THE FRONT MOVES THROUGH WILL DICTATE HOW WARM WE GET ON
THU. IF THE FRONT MOVES QUICK ENOUGH...WE COULD HAVE A CHC TO WARM
TOWARD 90 WITH H850 TEMPS OF 20C ADVECTING IN. FOR NOW...WE HAVE
SETTLED WITH THE MID-UPPER 80S WITH THE UNCERTAINTY OF THE PCPN.
WE WILL SEE ANOTHER BATCH OF CONVECTION BE POSSIBLE THEN CENTERED
AROUND FRI AS THE COLD FRONT PUSHES THROUGH AND ENCOUNTERING THE
VERY WARM AND MOIST AIR MASS. WE COULD HAVE SOME ASSISTANCE VIA THE
RRQ OF AN UPPER JET TO OUR N/NE THAT WOULD SUPPLEMENT THE COLD
FRONTAL PASSAGE.
THE REMAINDER OF THE LONG TERM FROM SAT THROUGH SUN LOOKS TO BE
RATHER QUIET...YET COOL. WE WILL SEE A CANADIAN AIR MASS FILTER IN
BEHIND THE THU/FRI SYSTEM WITH A DECENT NNE LOW LEVEL FLOW USHERING
IT IN. THE UPPER FLOW WILL BE FROM THE NW AND A BIT OF A TROUGH WILL
BE OVER THE AREA. THE FAR ERN FLANK OF A SFC RIDGE WILL BE
BUILDING IN AS THE SYNOPTIC PATTERN OVER THE COUNTRY WILL FEATURE A
FAIRLY BROAD/EXPANSIVE UPPER RIDGE FROM THE ERN PACIFIC INTO THE
ROCKIES. THIS SHOULD KEEP THE AREA DRY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 122 PM EDT MON SEP 1 2014
A LINE OF SHOWERS AND THUNDERSTORMS WILL CROSS LOWER MICHIGAN THIS
AFTERNOON. BRIEF PERIODS OF HEAVY RAINFALL IS POSSIBLE WITH VSBYS
FALLING TO IFR/MVFR CONDITIONS. THE ACTUAL COLD FRONT WON/T PASS
THROUGH UNTIL AFTER MIDNIGHT. AS A RESULT...WE KEPT MVFR CIGS IN
THE TAFS UNTIL AROUND MIDNIGHT.
&&
.MARINE...
ISSUED AT 1100 AM EDT MON SEP 1 2014
SCA/BEACH HAZARD WORKING WELL WITHWIND GUSTS NEAR 30 KTS AND WAVE
AROUND 4 FT OBSERVED NORTH OF HOLLAND TOWARDS LUDINGTON AT THIS
TIME. WINDS WILL CONTINUE NEXT SEVERAL HOURS WITH WAVES UP TO 5
FEET. WINDS / WAVES WILL SUBSIDE QUICKLY LATE THIS AFTERNOON WITH
PASSAGE OF FRONT AND SHIFT OF WINDS TO A MORE WESTERLY DIRECTION.
THE NEXT POSSIBLE SET OF HEADLINES THAT MAY BE NEEDED FOR THE
NEARSHORE WATERS LOOKS TO START IN THE WED NIGHT/THU TIME FRAME AS
THE FLOW STRENGTHENS WITH A SURGE OF WARMER AIR WITH THE NEXT
FRONTAL SYSTEM POISED TO MOVE IN.
&&
.HYDROLOGY...
ISSUED AT 1237 PM EDT MON SEP 1 2014
RIVERS ARE RUNNING A LITTLE ABOVE NORMAL... BUT ARE STILL FAR BELOW
BANK FULL. PRECIPITATION THROUGH THIS EVENING IS EXPECTED TO TOTAL
AROUND A QUARTER OF AN INCH WITH ISOLATED LOCATIONS NORTHWEST OF
GRAND RAPIDS RECEIVING NEARLY AN INCH. THIS SHOULD LEAD TO SMALL
RISES ON AREA RIVERS WITH PEAK LEVELS BELOW BANK FULL BY MID WEEK.
ADDITIONAL PRECIPITATION IS POSSIBLE WEDNESDAY INTO FRIDAY NIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT UNTIL 10 PM EDT THIS EVENING FOR MIZ037-
043-050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LMZ844>849.
&&
$$
SYNOPSIS...DUKE
SHORT TERM...COBB
LONG TERM...NJJ
AVIATION...93
HYDROLOGY...63
MARINE...COBB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
123 PM EDT MON SEP 1 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 510 AM EDT MON SEP 1 2014
WV IMAGERY AND RUC INDICATED A BROAD MID/UPPER LEVEL TROUGH FROM THE
ROCKIES INTO THE NRN/CNTRL PLAINS. AT THE SFC...A COLD FRONT
EXTENDED FROM NEAR INL THROUGH CNTRL MN INTO NW IA. A WEAK SHRTWV
FROM NE MN INTO NW WI SUPPORTED AN AREA OF SHOWERS AND ISOLD TSRA
OVER ERN MN INTO NW WI AND LAKE SUPERIOR. A STRONGER SHRTWV WAS
LOCATED OVER SW MN INTO NW IA. WITH ONLY MODEST 500-1000 J/KG
MUCAPE...ONLY A FEW TSRA WERE NOTED OVER THE REGION. THE MORE ACTIVE
CONVECTION OVER ERN LAKE SUPERIOR WAS ASSOCIATED WITH AN AREA OF
STRONGER 850 THETA-E ADVECTION AT THE NOSE OF THE LLJ.
TODAY...AS THE NW IA SHRTWV LIFTS TOWARD THE AREA WITH MODERATE
700-300 MB QVECTOR CONV AND THE COLD FRONT APPROACHES THE
AREA...EXPECT SHRA/TSRA COVERAGE TO INCREASE THIS MORNING. EVEN WITH
0-1KM/0-6KM SHEAR AROUND 40 KNOTS...SINCE INSTABILITY WILL REMAIN
LIMITED...MAINLY JUST BRIEF HEAVY RAIN IS EXPECTED. OVERALL RAINFALL
AMOUNTS SHOULD BE LIMITED GIVEN THE QUICK MOVEMENT OF THE CONVECTIVE
CELLS AND LACK OF LARGE SCALE ORGANIZATION. THE PCPN WILL DIMINISH
FROM WEST TO EAST THIS AFTERNOON AS THE COLD FRONT MOVES THROUGH AND
QVECTOR DIV SPREADS INTO UPPER MI IN THE WAKE OF THE SHRTWV. CLOUD
COVER WILL KEEP HIGH TEMPS NEAR OR SLIGHTLY BELOW SEASONAL AVERAGES
IN THE UPPER 60S TO AROUND 70.
TONIGHT...ANY LINGERING PCPN OVER THE ERN CWA IN THE EVENING WILL
END EARLY. OTHERWISE...A DRIER AIRMASS MOVING INTO THE AREA WITH
DEWPOINTS DROPPING TOWARD THE LOWER 50S WILL ALLOW TEMPS TO ALSO
DROP INTO THE LOWER TO MID 50S AS SKIES PARTIALLY CLEAR. AN INCREASE
IN CLOUD COVER IS EXPECTED LATE OVER THE SW CWA AHEAD OF THE NEXT
WEAK SHRTWV.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 321 AM EDT MON SEP 1 2014
IN THE WAKE OF STRONGER SHORTWAVE AND SFC FRONT MOVING THROUGH
TODAY...ANOTHER SHORTWAVE CLIPS ACROSS THE AREA ON TUESDAY IN
INCREASINGLY ZONAL FLOW ALOFT. MOISTURE IS LIMITED WITH THE WAVE AS
SOUNDINGS ONLY SHOW MOISTURE H8-H7. PRETTY HIGH BASED SHRA AND WILL
ALSO MENTION ISOLD TSRA WITH MLCAPE 500-1000 J/KG PER ECMWF AND GFS.
WILL INCLUDE SLIGHT CHANCE POPS. A LULL FOR TUE NIGHT AS SFC RIDGE
MOVES FROM MIDDLE MISSISSIPPI RIVER VALLEY TO THE OHIO VALLEY. LGT
SW WINDS ON PERIFERY OF THE RIDGE WILL LIMIT COOLING. LOWEST PWAT
FAR EAST CWA WHERE MIN TEMPS MAY FALL TO AROUND 50 DEGREES. ON
WEDNESDAY...GFS AND GEM-NH INDICATE SOME SHOWERS COULD OCCUR IN THE
AFTN OVER MAINLY THE WEST HALF CWA. WEAK SHORTWAVE IS THERE BUT ONLY
APPEARS THAT BEST MOISTURE INFLOW IS OVER FAR WEST CWA. WARM AIR
ADVECTION BOOSTS H85 TEMPS TO AROUND +15C SO AS LONG AS SKIES STAY
AT LEAST PARTLY CLOUDY...MAX TEMPS WILL TOP OUT IN THE MID 70S TO
LOWER 80S.
LATER WEDNESDAY NIGHT INTO THURSDAY MORNING LARGER SCALE LIFT
AHEAD OF UPPER TROUGH INCREASES OVER NORTHERN PLAINS AND WESTERN
GREAT LAKES. LIKELY WILL BE SOME SHORTWAVES SLIDING OUT OF NORTHERN
PLAINS AS WELL...THOUGH RIGHT NOW SIGNAL OF ANY STRONGER SHORTWAVE
IS MINIMAL. THERE IS A MID LEVEL JET MAX SLIDING OVER THE AREA AND
H85-H5 Q-VECTOR CONVERGENCE WILL BE ON THE INCREASE. PRIMARY SFC
TROUGH WILL BE OVER MINNESOTA AND BASED ON SFC WINDS AND
DWPNTS...THERE WILL BE A WARM FRONT VCNTY OF SOUTHERN/CENTRAL
MINNESOTA INTO WESTERN WISCONSIN. BULGE OF WARMTH ALOFT RESULTS IN
AN ELEVATED MIXED LAYER WITH H7-H5 LAPSE RATES OVER 8C/KM MAKING IT
OVER UPR LAKES AHEAD OF THE SFC TROUGH. RESERVOIR OF ML MUCAPE OVER
2000J/KG WILL BE JUST SOUTHWEST OF UPR MICHIGAN WITH MID LEVEL FLOW
SW-NE. EDGE OF SFC BASED CAPE AND ORIENTATION OF H85-H3 THICKNESSES
INDICATE THAT STRONGER STORMS MAY BE MORE TO SOUTHWEST OF UPR
MICHIGAN LATER WEDNESDAY NIGHT INTO THURSDAY MORNING. TOUGH TO SAY
AT THIS POINT THOUGH. CONSENSUS CHANCE POPS WORK FOR NOW SINCE THERE
WILL BE LARGE SCALE WARM AIR ADVECTION AND H85-H7 MOISTURE TRANSPORT
AIMED INTO THE AREA. MORE SHRA/TSRA POSSIBLE AS SFC FRONT WORKS
ACROSS UPR MICHIGAN LATER ON THURSDAY. PLENTY OF INSTABILITY AS
TEMPS IN THE SOUTH-SOUTHWEST FLOW AHEAD OF FRONT SHOULD REACH TOWARD
80 DEGREES WITH EVEN A FEW HOURS OF PARTIAL CLEARING SINCE H85 TEMPS
ARE 18-20C. MOISTURE AVAILABILITY/MID LEVEL CAPPING ALONG THE FRONT
REMAINS A CONCERN FOR COVERAGE OF SFC BASED STORMS IN THE AFTN. MODELS
MAY BE PICKING UP ON THIS AS GFS/ECMWF SHOW A MIN IN QPF 18Z-24Z BUT
THEN INCREASE IT BY 06Z ON FRIDAY AS FRONT WILL MAINLY BE SOUTH AND
EAST OF CWA BY THAT TIME. NO NEED TO GET TOO FANCY WITH THE GRIDS
ATTM GIVEN ALL THE UNCERTAINTY. KEPT WITH THE CONSENSUS CHANCE POPS
ON THURSDAY WITH THIS DROPPING OFF TO LOWER CHANCES THURSDAY NIGHT
CLOSER TO THE DEPARTING FRONT.
REST OF THE FORECAST LOOKS DRY AND COOLER AS HIGH PRESSURE BUILDS IN
ON FRIDAY AND WILL HOLD ON THROUGH NEXT WEEKEND. MAX TEMPS IN THE
MID 60S TO LOWER 70S. CHILLY LOWS POSSIBLE INLAND BOTH FRIDAY NIGHT
AND SATURDAY NIGHT DUE TO THE DRY AIRMASS AND LGT WINDS BENEATH THE
HIGH PRESSURE. BIAS CORRECTED GUIDANCES SHOWED MINS IN THE LOWER 40S
BUT WOULD NOT BE SURPRISED TO SEE READINGS DIPPING INTO THE 30S
EITHER OF THOSE NIGHTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 122 PM EDT MON SEP 1 2014
IWD...MVFR CONDITIONS WILL PREDOMINATE EARLY BEFORE DRIER AIR MOVES
IN AND ALLOWS FOR CONDITIONS TO IMPROVE TO VFR BY THIS EVENING.
CMX...CONTINUED -SHRA EARLY SHOULD RESULT IN A PERIOD OF IFR
CONDITIONS DURING THE EARLY AFTERNOON BEFORE THE W WIND TAPS DRIER
AIR AND RESULTS IN IMPROVEMENT TO VFR THIS EVENING.
SAW...SOME SHRA WITH MVFR CONDITIONS WILL CONTINUE WITH THE APPROACH
OF A SFC COLD FRONT MOVING THROUGH EARLY THIS PERIOD. EXPECT
IMPROVEMENT LATE IN THE AFTERNOON WITH A WSHFT TO A DOWNSLOPE W
DIRECTION AND THE ARRIVAL OF DRIER AIR FOLLOWING THE FROPA.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 510 AM EDT MON SEP 1 2014
WINDS WILL BE 20 KNOTS OR LESS THROUGH THIS FORECAST PERIOD WITH
AREAS OF FOG PERSISTING UNTIL DRIER AIR MOVES INTO THE REGION
TONIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
114 PM EDT MON SEP 1 2014
.AVIATION...
//DISCUSSION...
LOW STRATUS CONTINUES TO MIX UP TO LOW VFR DIURNALLY FORCED CU.
EXPECT THIS TREND TO CONTINUE THROUGH THE NEAR TERM. ATTENTION
THEN TURNS TOWARD TSTORM CHANCES THIS AFTERNOON. CAPPING WILL
LIMIT POTENTIAL SOUTH OF KPTK SO TSHRA WAS REMOVED FOR THESE
LOCATIONS AS THE PROBABILITY IS NOW TOO LOW TO WARRANT A MENTION
IN THE TAFS. EXPECTATIONS REMAIN UNCHANGED FROM KFNT NORTH
UPSTREAM ACTIVITY IS MORE CERTAIN TO MOVE IN THIS AFTERNOON. LOW CLOUDS AND
PERHAPS A VISIBILITY RESTRICTION WILL BE POSSIBLE BEHIND THE FRONT
LATE TONIGHT BUT ONCE AGAIN EXPECT PRECIP POTENTIAL TO REMAIN
RATHER LOW WITH THE BULK OF 12Z GUIDANCE HOLDING ACTIVITY SOUTH OF
THE MICHIGAN BORDER.
FOR DTW...ALTHOUGH CONFIDENCE IN TSTORMS HAS DECREASED...IT AT LEAST
REMAINS PLAUSIBLE. THE BEST TIME FOR A THUNDERSTORM TO IMPACT THE
AIRPORT WILL BE 21Z-23Z THIS AFTERNOON. CONFIDENCE IN SHOWER
COVERAGE TOWARD MORNING IS ALSO QUITE LOW. ELECTED TO ELIMINATE
SPECIFIC MENTION FROM THE TAF UNTIL POTENTIALLY IMPACTED AREA BECOMES
MORE CLEAR.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILINGS BELOW 5KFT THIS AFTERNOON AND LATE TONIGHT
* LOW CONFIDENCE THAT A TSTORM WILL IMPACT KDTW
&&
.PREV DISCUSSION...ISSUED 1227 PM EDT MON SEP 1 2014
UPDATE...
MOST OF SOUTHEAST MICHIGAN REMAINS SHROUDED IN LOW AND MID-LEVEL
CLOUDS EARLY THIS AFTERNOON, ALTHOUGH THE LATEST TRENDS ON VISIBLE
INDICATE THAT THE STRATUS DECK HAS BEGUN TO EVOLVE TOWARD A
DIURNALLY FORCED CU FIELD. AS A RESULT, TEMPERATURES HAVE RISEN INTO
THE MID TO UPPER 70S FROM WESTERN LOWER MI NORTHEASTWARD INTO THE
THUMB WHILE DEWPOINTS REMAIN LOCKED IN AROUND 70 DEGREES.
THE STOUT 600MB CAP INDICATED ON THIS MORNING`S SOUNDING REMAINS THE
ONLY IMPEDANCE, ALBEIT A POTENTIALLY SIGNIFICANT ONE, TO WIDESPREAD
SEVERE WEATHER THIS AFTERNOON. CAP NOTWITHSTANDING, THERMODYNAMIC
PROFILES ARE IMPRESSIVE. MODERATE DESTABILIZATION IS STILL FAVORED
GIVEN THE ABUNDANCE OF LOW-LEVEL MOISTURE AND SURFACE TEMPERATURES
ALREADY PUSHING UPPER 70S AT NOON. 0-6KM BULK SHEAR FEATURING
VEERING THROUGH THE LOWEST 1.5KM AGL AND AFOREMENTIONED DEGREE OF
DESTABILIZATION WILL SUPPORT AN INITIAL CONVECTIVE MODE OF
SUPERCELLS. ANY SUPERCELLS WILL CARRY TORNADIC POTENTIAL GIVEN
FAVORABLE THERMODYNAMIC PROFILES FOR STRETCHING IN THE LOWEST
LEVELS, VEERED SFC-1KM WIND PROFILES, AND REASONABLY LOW LCLS OF
700-900M. UNIDIRECTIONAL MID-LEVEL WIND PROFILE AND PLENTY DRY AIR
WOULD THEN SUPPORT A QUICK EVOLUTION TOWARD DOWNDRAFT MODULATED
CONVECTION AND A CORRESPONDING EVOLUTION TOWARD DYNAMIC BOWS EARLY
IN THE CONVECTIVE CYCLE. GIVEN THE HIGH FREEZING LEVELS, THE LACK
OF MESOCYCLONE FORCING WITHIN BOWS WILL TEND TO LIMIT THE THREAT
TO WIND ONLY.
IN SPITE OF THE RIPE ENVIRONMENT, CAPPING LOOMS LARGE. THE 12Z NAM12
ALLOWS ENCROACHING HEIGHT FALLS TO USHER IN SUFFICIENT MID-LEVEL
COOLING SUPPORTIVE OF STRONG, DEEP CONVECTION THROUGH THE
EARLY/MID AFTERNOON. AT THE SAME TIME, THE LAST SEVERAL RUNS OF
THE RAP IS CONSIDERABLY SLOWER COOLING THE COLUMN AND LIMITS ANY
SEVERE THREAT TO THE SAGINAW VALLEY AREA WHERE MID-LEVEL
COOLING/FORCING WILL BE MAXIMIZED. THE SOLUTION SPACE REMAINS WIDE
OPEN AND CONFIDENCE IN SEVERE WX IS CORRESPONDINGLY LOW. AT THIS
POINT, EVEN COVERAGE OF CONVECTION SEEMS TO BE IN QUESTION,
PARTICULARLY IF THE LATEST NON NAM GUIDANCE IS TO BE BELIEVED. IN
PURSUIT OF CLARITY, AN 18Z SOUNDING IS FORTHCOMING.
PREV DISCUSSION...ISSUED 405 AM EDT MON SEP 1 2014
SHORT TERM... TODAY AND TONIGHT
THUNDERSTORMS AND THE POTENTIAL FOR SEVERE WEATHER WILL BE THE
PRIMARY SUBJECT OF THE FORECAST FOR TODAY AND TONIGHT AS INGREDIENTS
COME TOGETHER FOR AN ACTIVE AFTERNOON AND EVENING AROUND SE
MICHIGAN. A FEW ELEVATED SHOWERS OR WEAK THUNDERSTORMS WILL BE
POSSIBLE DURING THE MORNING AS THE WARM SECTOR OF THE BROAD LOW
PRESSURE SYSTEM BUILDS INTO LOWER MICHIGAN. EXPECT THIS TO BE
FOLLOWED BY SURFACE BASED STORMS LIKELY INITIATING IN THE LEE OF
LAKE MICHIGAN EARLY TO MID AFTERNOON AND PROGRESSING THROUGH SE
MICHIGAN AS THE LEADING EDGE OF THE UPPER WAVE/MCV REMNANTS INTERACT
WITH THE LOW LEVEL MOISTURE AXIS DURING PEAK HEATING. A SECOND ROUND
OF STORMS IS THEN LIKELY TO INITIATE ALONG AND AHEAD OF THE COLD
FRONT AND FOLLOW THE AFTERNOON STORMS THROUGH OUR AREA MID EVENING
THROUGH THE OVERNIGHT.
EARLY MORNING IR SATELLITE IMAGERY INDICATES STRONGLY WARMING CLOUD
TOPS ASSOCIATED WITH THE UPSTREAM CONVECTION WHICH SUPPORTS THE
DISSIPATING TREND ADVERTISED IN MODEL DATA AND THE SCENARIO OF NEW
DEVELOPMENT OVER LOWER MICHIGAN DURING THE DAY. THIS DISSIPATING
TREND IS HAPPENING SOON ENOUGH TO ALLOW DEBRIS CLOUDS TO ERODE
AND/OR GET CARRIED TO OUR WEST AND NORTH BY THE SOUTHWEST FLOW
ALOFT. THAT LEAVES JUST PATCHY MID CLOUDS...ALONG WITH AREAS OF FOG
AND LOW STRATUS...AS A MINIMAL OBSTRUCTION TO STRONG SURFACE HEATING
TO START THE DAY. IT THEN SEEMS REASONABLE TO ASSUME MAX TEMPS OF
80-85 WILL BE REACHABLE WITH SURFACE DEWPOINT AROUND 70 CARRYING
0-1KM LAYER CAPE TOWARD 1500 J/KG. A SURFACE PARCEL AT 85/72
GENERATES SURFACE BASED CAPE NEAR 2500 J/KG AS A WORST CASE
SCENARIO. THESE VALUES ARE PLENTY HIGH ENOUGH TO INTERACT WITH A
STRENGTHENING UNIDIRECTIONAL WIND PROFILE INCREASING TO NEAR 40 KNOTS
OF BULK SHEAR IN THE 0-6KM LAYER...WITH MOST OF THAT IN THE 0-3KM
LAYER. THIS WILL ALLOW DISCRETE CELLS TO DEVELOP SUPERCELL CHARACTER
EARLY ON WITH SPLITS AND MERGERS GROWING UPSCALE INTO LINEAR SEGMENTS
AS CONVECTION MATURES LATE AFTERNOON INTO EARLY EVENING. DAMAGING
WIND WILL BE THE PRIMARY HAZARD. LARGE HAIL WILL BE POSSIBLE BUT
LIKELY LIMITED TO ONLY THE STRONGEST MESO ENHANCED UPDRAFTS DUE TO
HIGH FREEZING LEVEL. IT IS ALSO IMPORTANT TO NOTE THAT MODEL
SOUNDINGS INDICATE CAPE EXCEEDING 300 J/KG IN THE LOWEST 3 KM ALONG
WITH 0-3 KM HELICITY AROUND 200 M2/S2 AND LCL BETWEEN 3500 AND 4000
FT. THESE ARE FAVORABLE PARAMETERS FOR TORNADOGENESIS.
ROUND TWO OF STORMS WILL BE TRIGGERED BY THE COLD FRONT WEST OF LAKE
MICHIGAN DURING THE LATE AFTERNOON. SEVERE POTENTIAL WITH THIS
ACTIVITY WILL BE LOWER BY THE TIME IT REACHES OUR AREA TOWARD LATE
EVENING INTO THE OVERNIGHT...BOTH DUE TO THE DOWNSIDE OF DAYTIME
HEATING AND THE PRECEDING STORMS. HEAVY RAINFALL MAY END UP BEING
THE MAIN CONCERN AS THE THE SLOW MOVING COLD FRONT ENDS UP THE FOCUS
OF LARGE SCALE SUPPORT FROM THE ENTRANCE REGION OF THE UPPER JET AND
CONTINUED LOW LEVEL MOISTURE TRANSPORT. THIS WILL DEPEND ON HOW MUCH
POST FRONTAL/ELEVATED CONVECTION IS ABLE TO OCCUR WHICH THE MODELS
SUGGEST WILL BE MINIMAL...INSTEAD FOCUSING ADDITIONAL RAINFALL ALONG
AND AHEAD OF THE FRONT THROUGH SUNRISE TUESDAY.
LONG TERM...
WARMER/ABOVE NORMAL TEMPERATURES APPEAR TO BE IN STORE FOR THE FIRST
SEVERAL DAYS OF SEPTEMBER.
BROAD UPPER LEVEL TROUGH WILL BE SWINGING THROUGH THE CENTRAL GREAT
LAKES ON TUESDAY...AND IT APPEARS THE SURFACE COLD FRONT/MOISTURE
AXIS WILL HAVE CLEARED SOUTHEAST MICHIGAN AROUND 12Z TUESDAY...WITH
A DRAMATIC DRYING TREND TAKING PLACE AS PW VALUES AROUND 2 INCHES
NEAR THE OHIO BORDER ARE JUST ABOUT CUT IN HALF TO AROUND 1 INCH.
HOWEVER...THERE IS AN EMBEDDED STRONG SHORTWAVE QUICKLY TRACKING OUT
OF EASTERN IOWA EARLY TUESDAY MORNING...AND NEED TO ACCOUNT FOR THE
POSSIBILITY OF THE FLOW OUT AHEAD OF THIS FEATURE A BIT MORE
BACKED...SLOWING THE PROGRESS OF THE FRONTAL BOUNDARY TO THE
SOUTH...AND CARRY LOW CHANCE POPS...AS DAYTIME SURFACE BASED
INSTABILITY SETS IN AS WELL...WITH AROUND 1000 J/KG TO WORK WITH PER
00Z NAM. ALTHOUGH...THE 00Z GFS IS DRIER AND DECIDEDLY MORE
ANTICYCLONIC AT THE SURFACE...WHILE THE CANADIAN IS THE WETTEST.
SHORT LIVED ENERGETIC ZONAL FLOW OVER THE NORTHERN CONUS TUESDAY
NIGHT WITH STRONGER UPPER WAVE DIVING SOUTHEAST THROUGH THE PACIFIC
NORTHWEST. HEIGHTS WILL REBOUND OVER THE EASTERN CONUS
WEDNESDAY/THURSDAY WITH FAVORABLE DEEP SOUTHWEST FLOW AROUND SURFACE
HIGH CENTERED OVER THE EASTERN SEABOARD. HIGHS THE 80S APPEAR IN
THE OFFING...AS 850 MB TEMPS RISE TOWARD 20 C ON THURSDAY...AND
REACH OR POSSIBLY SLIGHTLY EXCEED 20 C ON FRIDAY...WHICH MAKES A RUN
TOWARD A 90 DEGREE DAY A REAL POSSIBILITY. HOWEVER...A COLD FRONT
WILL PROBABLY ALREADY BE ARRIVING...SUPPORTING CLOUDS AND A GOOD
CHANCE OF SHOWERS AND THUNDERSTORMS...WHICH OF COURSE WOULD HINDER
MAXES. MUCH LOWER CHANCE OF PRECIPITATION ON THURSDAY AS WARM FRONT
LIFTS THROUGH THE WESTERN GREAT LAKES.
MARINE...
SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON...AND CONTINUE
TONIGHT AS A COLD FRONT MOVES THROUGH LAKE HURON AND LOWER MICHIGAN.
SOME OF THESE STORMS MAY BE SEVERE. HIGH PRESSURE WILL BUILD INTO
THE REGION BEHIND THIS FRONT ON TUESDAY...WHICH WILL REMAIN IN
CONTROL OF THE WEATHER THROUGH THURSDAY...PROVIDING FAVORABLE
BOATING CONDITIONS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....JVC
UPDATE.......JVC
SHORT TERM...BT
LONG TERM....SF
MARINE.......SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1237 PM EDT MON SEP 1 2014
LATEST UPDATE...
HYDRO
.SYNOPSIS...
ISSUED AT 330 AM EDT MON SEP 1 2014
A COLD FRONT WILL MOVE INTO THE GREAT LAKES REGION FROM THE WEST
LATER TODAY AND INTO TONIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED
TO DEVELOP OVER SOUTHWEST LOWER MICHIGAN FROM THE LATE MORNING HOURS
PERSISTING INTO THE EVENING. SOME OF THE STORMS FROM THE MIDDAY
HOURS THROUGH THE EVENING MAY BE SEVERE WITH LARGE HAIL AND STRONG
WINDS. SHOWERS AND STORMS WILL GRADUALLY TAPER OFF TONIGHT
FROM NORTH TO SOUTH AS THE FRONT DROPS SOUTHWARD INTO INDIANA. DRY
WEATHER IS THEN EXPECTED FOR THE MOST PART FROM TUESDAY THROUGH
WEDNESDAY. CHANCES FOR SHOWERS AND STORMS INCREASE ONCE AGAIN
WEDNESDAY NIGHT THROUGH FRIDAY AS A LOW PRESSURE SYSTEM TRAVERSES
THE AREA. TEMPERATURES THIS WEEK WILL BE NEAR TO ABOVE NORMAL WITH
HIGHS IN THE UPPER 70S TO 80S ALL WEEK. A COOL DOWN IS EXPECTED NEXT
WEEKEND BEHIND A COLD FRONT THAT MOVES THROUGH ON FRIDAY.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 1100 AM EDT MON SEP 1 2014
ISOLATED SEVERE WEATHER THREAT CONTINUES THIS AFTERNOON (2PM - 8PM)
EAST OF U.S. 131 WITH DAMAGING WIND GUSTS THE MAIN THREAT. BRIEF
LOCALIZED FLOODING TYPICAL OF STRONG THUNDERSTORMS IS ALSO POSSIBLE.
APPROACHING WEAK FRONTAL BOUNDARY...SEPARATING DEWPOINTS IN THE LOW
70S FROM THOSE IN THE MID 60S...IS CURRENTLY ORIENTED NORTH-SOUTH
ACROSS EASTERN WISCONSIN AND ILLINOIS. THERE IS ALSO CONSIDERABLE
CLOUDINESS ALONG AND AHEAD OF FRONT WHICH IS TEMPERATURES AND
DESTABILIZATION OFTHE AIRMASS.
THE FRONT WILL SWEEP EASTWARD ACROSS THE CWA THIS AFTERNOON AND
EARLY EVENING PROVIDING LOW LEVEL LIFT AND POTENTIAL FOCUS FOR
DEVELOPMENT OF NEW STORMS. ALOFT HOWEVER...THE LEAD SHORTWAVE AND
NOSE OF UPPER JET WILL PUSH EASTWARD OVER THE REGION WITH BEST DEEP
LIFT NORTH MAINLY NORTH OF THE AREA.
INSTABILITY AND WIND FIELDS ARE FAVORABLE FOR SEVERE STORMS WITH
CAPE VALUES OF 500 - 1500 J/KG...0-6 KM BULK SHEAR VALUES NEAR 40
KTS...AND 0-1KM SHEAR VALUES AROUND 20 KTS. HOWEVER...LACK OF DEEP
LIFT WILL LIMIT COVERAGE OF STORMS AND OVERALL SEVERE THEAT
SIGNICANTLY. THIS SOLUTION IS REFLECTED IN MANY OF THE HIGHER
RESOLUTION CONVECTION ALLOWING MODELS INCLUDING LAST FEW NSSL WRF
AND HRRR RUNS.
OTHERWISE...THE SHORT TERM IS RELATIVELY QUIET. ANY STORMS THIS
EVENING SHOULD WORK SOUTH OF THE AREA OVERNIGHT. NOT OUT OF THE
REALM OF POSSIBILITIES FOR A FEW SHOWERS ON TUESDAY...BUT FELT THE
THREAT WAS SMALL ENOUGH TO GO DRY. TUESDAY NIGHT AND WEDNESDAY
SHOULD BE DRY WITH RIDGING IN PLACE AT THE SURFACE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM EDT MON SEP 1 2014
THE MOST UNSETTLED WEATHER IN THE LONG TERM LOOKS TO OCCUR IN THE
FIRST COUPLE OF DAYS...FROM THE BEGINNING OF THE PERIOD WED NIGHT
INTO FRI NIGHT. THE LATEST TREND IS FOR A LITTLE MORE POSSIBLE PCPN
WED NIGHT INTO THU WITH THE PASSAGE OF THE WARM FRONT THROUGH THE
AREA. THIS LOOKS TO BE THE CASE DUE TO THE GRADIENT/LOW LEVEL JET
EXPECTED TO BE A LITTLE STRONGER WITH A STRONGER TROUGH MOVING IN.
HOW QUICKLY THE FRONT MOVES THROUGH WILL DICTATE HOW WARM WE GET ON
THU. IF THE FRONT MOVES QUICK ENOUGH...WE COULD HAVE A CHC TO WARM
TOWARD 90 WITH H850 TEMPS OF 20C ADVECTING IN. FOR NOW...WE HAVE
SETTLED WITH THE MID-UPPER 80S WITH THE UNCERTAINTY OF THE PCPN.
WE WILL SEE ANOTHER BATCH OF CONVECTION BE POSSIBLE THEN CENTERED
AROUND FRI AS THE COLD FRONT PUSHES THROUGH AND ENCOUNTERING THE
VERY WARM AND MOIST AIR MASS. WE COULD HAVE SOME ASSISTANCE VIA THE
RRQ OF AN UPPER JET TO OUR N/NE THAT WOULD SUPPLEMENT THE COLD
FRONTAL PASSAGE.
THE REMAINDER OF THE LONG TERM FROM SAT THROUGH SUN LOOKS TO BE
RATHER QUIET...YET COOL. WE WILL SEE A CANADIAN AIR MASS FILTER IN
BEHIND THE THU/FRI SYSTEM WITH A DECENT NNE LOW LEVEL FLOW USHERING
IT IN. THE UPPER FLOW WILL BE FROM THE NW AND A BIT OF A TROUGH WILL
BE OVER THE AREA. THE FAR ERN FLANK OF A SFC RIDGE WILL BE
BUILDING IN AS THE SYNOPTIC PATTERN OVER THE COUNTRY WILL FEATURE A
FAIRLY BROAD/EXPANSIVE UPPER RIDGE FROM THE ERN PACIFIC INTO THE
ROCKIES. THIS SHOULD KEEP THE AREA DRY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 749 AM EDT MON SEP 1 2014
COMPLICATED WEATHER SCENARIO IN PLACE THIS MORNING WITH STRATUS
MOVING NORTH THROUGH THE TAF SITES AND THE POTENTIAL FOR
THUNDERSTORMS LOOMING.
THE STRATUS AND FOG SHOULD GRADUALLY LIFT THROUGH THE COURSE OF
THE MORNING...BUT IT HAS BECOME FAIRLY EXTENSIVE ACROSS SOUTHERN
LOWER MICHIGAN. BY AFTERNOON...EXPECTING VFR CEILINGS AND VSBYS
OUTSIDE OF THUNDERSTORMS.
AS FOR THUNDERSTORMS...THEY ARE ALREADY DEVELOPING ACROSS
PORTIONS OF NORTHERN ILLINOIS AND NORTHERN INDIANA. THE TREND
SHOULD BE FOR SCATTERED SHOWERS AND THUNDERSTORMS TO MOVE THROUGH
THE TAF SITES FROM 14Z OR SO THROUGH 23Z. TOO DIFFICULT TO NAIL
DOWN PREVAILING TIMING AT THIS POINT GIVEN THE HIT OR MISS NATURE
TO TODAY/S STORMS...SO HAVE VCTS WORDING IN ALL THE TAFS THIS
AFTERNOON.
OVERNIGHT...EXPECTING THE SHOWERS AND STORMS TO END WITH MVFR
CEILINGS TRYING TO SETTLE BACK IN.
IT WILL BECOME WINDY TODAY OUT OF THE SOUTH-SOUTHWEST...ESPECIALLY
FROM 15Z-23Z. WINDS FROM 200-220 AT 15-25 KNOTS SHOULD BE COMMON.
&&
.MARINE...
ISSUED AT 1100 AM EDT MON SEP 1 2014
SCA/BEACH HAZARD WORKING WELL WITHWIND GUSTS NEAR 30 KTS AND WAVE
AROUND 4 FT OBSERVED NORTH OF HOLLAND TOWARDS LUDINGTON AT THIS
TIME. WINDS WILL CONTINUE NEXT SEVERAL HOURS WITH WAVES UP TO 5
FEET. WINDS / WAVES WILL SUBSIDE QUICKLY LATE THIS AFTERNOON WITH
PASSAGE OF FRONT AND SHIFT OF WINDS TO A MORE WESTERLY DIRECTION.
THE NEXT POSSIBLE SET OF HEADLINES THAT MAY BE NEEDED FOR THE
NEARSHORE WATERS LOOKS TO START IN THE WED NIGHT/THU TIME FRAME AS
THE FLOW STRENGTHENS WITH A SURGE OF WARMER AIR WITH THE NEXT
FRONTAL SYSTEM POISED TO MOVE IN.
&&
.HYDROLOGY...
ISSUED AT 1237 PM EDT MON SEP 1 2014
RIVERS ARE RUNNING A LITTLE ABOVE NORMAL... BUT ARE STILL FAR BELOW
BANK FULL. PRECIPITATION THROUGH THIS EVENING IS EXPECTED TO TOTAL
AROUND A QUARTER OF AN INCH WITH ISOLATED LOCATIONS NORTHWEST OF
GRAND RAPIDS RECEIVING NEARLY AN INCH. THIS SHOULD LEAD TO SMALL
RISES ON AREA RIVERS WITH PEAK LEVELS BELOW BANK FULL BY MID WEEK.
ADDITIONAL PRECIPITATION IS POSSIBLE WEDNESDAY INTO FRIDAY NIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT UNTIL 10 PM EDT THIS EVENING FOR MIZ037-
043-050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LMZ844>849.
&&
$$
SYNOPSIS...DUKE
SHORT TERM...COBB
LONG TERM...NJJ
AVIATION...DUKE
HYDROLOGY...63
MARINE...COBB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1227 PM EDT MON SEP 1 2014
.UPDATE...
MOST OF SOUTHEAST MICHIGAN REMAINS SHROUDED IN LOW AND MID-LEVEL
CLOUDS EARLY THIS AFTERNOON, ALTHOUGH THE LATEST TRENDS ON VISIBLE
INDICATE THAT THE STRATUS DECK HAS BEGUN TO EVOLVE TOWARD A
DIURNALLY FORCED CU FIELD. AS A RESULT, TEMPERATURES HAVE RISEN INTO
THE MID TO UPPER 70S FROM WESTERN LOWER MI NORTHEASTWARD INTO THE
THUMB WHILE DEWPOINTS REMAIN LOCKED IN AROUND 70 DEGREES.
THE STOUT 600MB CAP INDICATED ON THIS MORNING`S SOUNDING REMAINS THE
ONLY IMPEDANCE, ALBEIT A POTENTIALLY SIGNIFICANT ONE, TO WIDESPREAD
SEVERE WEATHER THIS AFTERNOON. CAP NOTWITHSTANDING, THERMODYNAMIC
PROFILES ARE IMPRESSIVE. MODERATE DESTABILIZATION IS STILL FAVORED
GIVEN THE ABUNDANCE OF LOW-LEVEL MOISTURE AND SURFACE TEMPERATURES
ALREADY PUSHING UPPER 70S AT NOON. 0-6KM BULK SHEAR FEATURING
VEERING THROUGH THE LOWEST 1.5KM AGL AND AFOREMENTIONED DEGREE OF
DESTABILIZATION WILL SUPPORT AN INITIAL CONVECTIVE MODE OF
SUPERCELLS. ANY SUPERCELLS WILL CARRY TORNADIC POTENTIAL GIVEN
FAVORABLE THERMODYNAMIC PROFILES FOR STRETCHING IN THE LOWEST
LEVELS, VEERED SFC-1KM WIND PROFILES, AND REASONABLY LOW LCLS OF
700-900M. UNIDIRECTIONAL MID-LEVEL WIND PROFILE AND PLENTY DRY AIR
WOULD THEN SUPPORT A QUICK EVOLUTION TOWARD DOWNDRAFT MODULATED
CONVECTION AND A CORRESPONDING EVOLUTION TOWARD DYNAMIC BOWS EARLY
IN THE CONVECTIVE CYCLE. GIVEN THE HIGH FREEZING LEVELS, THE LACK
OF MESOCYCLONE FORCING WITHIN BOWS WILL TEND TO LIMIT THE THREAT
TO WIND ONLY.
IN SPITE OF THE RIPE ENVIRONMENT, CAPPING LOOMS LARGE. THE 12Z NAM12
ALLOWS ENCROACHING HEIGHT FALLS TO USHER IN SUFFICIENT MID-LEVEL
COOLING SUPPORTIVE OF STRONG, DEEP CONVECTION THROUGH THE
EARLY/MID AFTERNOON. AT THE SAME TIME, THE LAST SEVERAL RUNS OF
THE RAP IS CONSIDERABLY SLOWER COOLING THE COLUMN AND LIMITS ANY
SEVERE THREAT TO THE SAGINAW VALLEY AREA WHERE MID-LEVEL
COOLING/FORCING WILL BE MAXIMIZED. THE SOLUTION SPACE REMAINS WIDE
OPEN AND CONFIDENCE IN SEVERE WX IS CORRESPONDINGLY LOW. AT THIS
POINT, EVEN COVERAGE OF CONVECTION SEEMS TO BE IN QUESTION,
PARTICULARLY IF THE LATEST NON NAM GUIDANCE IS TO BE BELIEVED. IN
PURSUIT OF CLARITY, AN 18Z SOUNDING IS FORTHCOMING.
&&
.AVIATION...ISSUED 703 AM EDT MON SEP 1 2014
//DISCUSSION...
FOG AND STRATUS IN THE WARM AND HUMID AIR OVER SE MICHIGAN WILL
PRESENT LIFR/IFR CONDITIONS AS THE FIRST CONCERN FOR AVIATION
INTERESTS. INCREASING SOUTH TO SOUTHWEST WIND AND SURFACE HEATING
WILL HELP LIFT THE FOG AND MIX THE LOW CLOUDS DURING THE MORNING.
THUNDERSTORMS WILL THEN BECOME THE MAIN CHALLENGE DURING THE
AFTERNOON AND TONIGHT. TWO ROUNDS OF STORMS ARE LIKELY TO AFFECT
THE ENTIRE TERMINAL CORRIDOR...FIRST DURING THE MID AFTERNOON TO
MID EVENING DURING THE WARMEST PART OF THE DAY...AND THEN FROM
LATE EVENING THROUGH THE OVERNIGHT AS A COLD FRONT MOVES SLOWLY
ACROSS SE MICHIGAN. THE MAIN AREA OF RAIN WILL BE ON TRACK TO EXIT
TO THE SOUTH AND EAST BY SUNRISE TUESDAY LEAVING BEHIND ANOTHER
ROUND OF FOG AND STRATUS BEHIND THE COLD FRONT.
FOR DTW... A STRAY SHOWER OR THUNDERSTORM WILL BE POSSIBLE DURING
THE MORNING AND EARLY AFTERNOON BUT THE MAIN WINDOW FOR STORMS AND
POSSIBLE SEVERE WEATHER REMAINS LATE AFTERNOON THROUGH EARLY EVENING
FOR DTW.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET DURING THE MORNING.
* MEDIUM CONFIDENCE IN THUNDERSTORM TIMING AND COVERAGE.
&&
.PREV DISCUSSION...ISSUED 405 AM EDT MON SEP 1 2014
SHORT TERM... TODAY AND TONIGHT
THUNDERSTORMS AND THE POTENTIAL FOR SEVERE WEATHER WILL BE THE
PRIMARY SUBJECT OF THE FORECAST FOR TODAY AND TONIGHT AS INGREDIENTS
COME TOGETHER FOR AN ACTIVE AFTERNOON AND EVENING AROUND SE
MICHIGAN. A FEW ELEVATED SHOWERS OR WEAK THUNDERSTORMS WILL BE
POSSIBLE DURING THE MORNING AS THE WARM SECTOR OF THE BROAD LOW
PRESSURE SYSTEM BUILDS INTO LOWER MICHIGAN. EXPECT THIS TO BE
FOLLOWED BY SURFACE BASED STORMS LIKELY INITIATING IN THE LEE OF
LAKE MICHIGAN EARLY TO MID AFTERNOON AND PROGRESSING THROUGH SE
MICHIGAN AS THE LEADING EDGE OF THE UPPER WAVE/MCV REMNANTS INTERACT
WITH THE LOW LEVEL MOISTURE AXIS DURING PEAK HEATING. A SECOND ROUND
OF STORMS IS THEN LIKELY TO INITIATE ALONG AND AHEAD OF THE COLD
FRONT AND FOLLOW THE AFTERNOON STORMS THROUGH OUR AREA MID EVENING
THROUGH THE OVERNIGHT.
EARLY MORNING IR SATELLITE IMAGERY INDICATES STRONGLY WARMING CLOUD
TOPS ASSOCIATED WITH THE UPSTREAM CONVECTION WHICH SUPPORTS THE
DISSIPATING TREND ADVERTISED IN MODEL DATA AND THE SCENARIO OF NEW
DEVELOPMENT OVER LOWER MICHIGAN DURING THE DAY. THIS DISSIPATING
TREND IS HAPPENING SOON ENOUGH TO ALLOW DEBRIS CLOUDS TO ERODE
AND/OR GET CARRIED TO OUR WEST AND NORTH BY THE SOUTHWEST FLOW
ALOFT. THAT LEAVES JUST PATCHY MID CLOUDS...ALONG WITH AREAS OF FOG
AND LOW STRATUS...AS A MINIMAL OBSTRUCTION TO STRONG SURFACE HEATING
TO START THE DAY. IT THEN SEEMS REASONABLE TO ASSUME MAX TEMPS OF
80-85 WILL BE REACHABLE WITH SURFACE DEWPOINT AROUND 70 CARRYING
0-1KM LAYER CAPE TOWARD 1500 J/KG. A SURFACE PARCEL AT 85/72
GENERATES SURFACE BASED CAPE NEAR 2500 J/KG AS A WORST CASE
SCENARIO. THESE VALUES ARE PLENTY HIGH ENOUGH TO INTERACT WITH A
STRENGTHENING UNIDIRECTIONAL WIND PROFILE INCREASING TO NEAR 40 KNOTS
OF BULK SHEAR IN THE 0-6KM LAYER...WITH MOST OF THAT IN THE 0-3KM
LAYER. THIS WILL ALLOW DISCRETE CELLS TO DEVELOP SUPERCELL CHARACTER
EARLY ON WITH SPLITS AND MERGERS GROWING UPSCALE INTO LINEAR SEGMENTS
AS CONVECTION MATURES LATE AFTERNOON INTO EARLY EVENING. DAMAGING
WIND WILL BE THE PRIMARY HAZARD. LARGE HAIL WILL BE POSSIBLE BUT
LIKELY LIMITED TO ONLY THE STRONGEST MESO ENHANCED UPDRAFTS DUE TO
HIGH FREEZING LEVEL. IT IS ALSO IMPORTANT TO NOTE THAT MODEL
SOUNDINGS INDICATE CAPE EXCEEDING 300 J/KG IN THE LOWEST 3 KM ALONG
WITH 0-3 KM HELICITY AROUND 200 M2/S2 AND LCL BETWEEN 3500 AND 4000
FT. THESE ARE FAVORABLE PARAMETERS FOR TORNADOGENESIS.
ROUND TWO OF STORMS WILL BE TRIGGERED BY THE COLD FRONT WEST OF LAKE
MICHIGAN DURING THE LATE AFTERNOON. SEVERE POTENTIAL WITH THIS
ACTIVITY WILL BE LOWER BY THE TIME IT REACHES OUR AREA TOWARD LATE
EVENING INTO THE OVERNIGHT...BOTH DUE TO THE DOWNSIDE OF DAYTIME
HEATING AND THE PRECEDING STORMS. HEAVY RAINFALL MAY END UP BEING
THE MAIN CONCERN AS THE THE SLOW MOVING COLD FRONT ENDS UP THE FOCUS
OF LARGE SCALE SUPPORT FROM THE ENTRANCE REGION OF THE UPPER JET AND
CONTINUED LOW LEVEL MOISTURE TRANSPORT. THIS WILL DEPEND ON HOW MUCH
POST FRONTAL/ELEVATED CONVECTION IS ABLE TO OCCUR WHICH THE MODELS
SUGGEST WILL BE MINIMAL...INSTEAD FOCUSING ADDITIONAL RAINFALL ALONG
AND AHEAD OF THE FRONT THROUGH SUNRISE TUESDAY.
LONG TERM...
WARMER/ABOVE NORMAL TEMPERATURES APPEAR TO BE IN STORE FOR THE FIRST
SEVERAL DAYS OF SEPTEMBER.
BROAD UPPER LEVEL TROUGH WILL BE SWINGING THROUGH THE CENTRAL GREAT
LAKES ON TUESDAY...AND IT APPEARS THE SURFACE COLD FRONT/MOISTURE
AXIS WILL HAVE CLEARED SOUTHEAST MICHIGAN AROUND 12Z TUESDAY...WITH
A DRAMATIC DRYING TREND TAKING PLACE AS PW VALUES AROUND 2 INCHES
NEAR THE OHIO BORDER ARE JUST ABOUT CUT IN HALF TO AROUND 1 INCH.
HOWEVER...THERE IS AN EMBEDDED STRONG SHORTWAVE QUICKLY TRACKING OUT
OF EASTERN IOWA EARLY TUESDAY MORNING...AND NEED TO ACCOUNT FOR THE
POSSIBILITY OF THE FLOW OUT AHEAD OF THIS FEATURE A BIT MORE
BACKED...SLOWING THE PROGRESS OF THE FRONTAL BOUNDARY TO THE
SOUTH...AND CARRY LOW CHANCE POPS...AS DAYTIME SURFACE BASED
INSTABILITY SETS IN AS WELL...WITH AROUND 1000 J/KG TO WORK WITH PER
00Z NAM. ALTHOUGH...THE 00Z GFS IS DRIER AND DECIDEDLY MORE
ANTICYCLONIC AT THE SURFACE...WHILE THE CANADIAN IS THE WETTEST.
SHORT LIVED ENERGETIC ZONAL FLOW OVER THE NORTHERN CONUS TUESDAY
NIGHT WITH STRONGER UPPER WAVE DIVING SOUTHEAST THROUGH THE PACIFIC
NORTHWEST. HEIGHTS WILL REBOUND OVER THE EASTERN CONUS
WEDNESDAY/THURSDAY WITH FAVORABLE DEEP SOUTHWEST FLOW AROUND SURFACE
HIGH CENTERED OVER THE EASTERN SEABOARD. HIGHS THE 80S APPEAR IN
THE OFFING...AS 850 MB TEMPS RISE TOWARD 20 C ON THURSDAY...AND
REACH OR POSSIBLY SLIGHTLY EXCEED 20 C ON FRIDAY...WHICH MAKES A RUN
TOWARD A 90 DEGREE DAY A REAL POSSIBILITY. HOWEVER...A COLD FRONT
WILL PROBABLY ALREADY BE ARRIVING...SUPPORTING CLOUDS AND A GOOD
CHANCE OF SHOWERS AND THUNDERSTORMS...WHICH OF COURSE WOULD HINDER
MAXES. MUCH LOWER CHANCE OF PRECIPITATION ON THURSDAY AS WARM FRONT
LIFTS THROUGH THE WESTERN GREAT LAKES.
MARINE...
SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON...AND CONTINUE
TONIGHT AS A COLD FRONT MOVES THROUGH LAKE HURON AND LOWER MICHIGAN.
SOME OF THESE STORMS MAY BE SEVERE. HIGH PRESSURE WILL BUILD INTO
THE REGION BEHIND THIS FRONT ON TUESDAY...WHICH WILL REMAIN IN
CONTROL OF THE WEATHER THROUGH THURSDAY...PROVIDING FAVORABLE
BOATING CONDITIONS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......JVC
AVIATION.....BT
SHORT TERM...BT
LONG TERM....SF
MARINE.......SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1100 AM EDT MON SEP 1 2014
LATEST UPDATE...
SHORT TERM
.SYNOPSIS...
ISSUED AT 330 AM EDT MON SEP 1 2014
A COLD FRONT WILL MOVE INTO THE GREAT LAKES REGION FROM THE WEST
LATER TODAY AND INTO TONIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED
TO DEVELOP OVER SOUTHWEST LOWER MICHIGAN FROM THE LATE MORNING HOURS
PERSISTING INTO THE EVENING. SOME OF THE STORMS FROM THE MIDDAY
HOURS THROUGH THE EVENING MAY BE SEVERE WITH LARGE HAIL AND STRONG
WINDS. SHOWERS AND STORMS WILL GRADUALLY TAPER OFF TONIGHT
FROM NORTH TO SOUTH AS THE FRONT DROPS SOUTHWARD INTO INDIANA. DRY
WEATHER IS THEN EXPECTED FOR THE MOST PART FROM TUESDAY THROUGH
WEDNESDAY. CHANCES FOR SHOWERS AND STORMS INCREASE ONCE AGAIN
WEDNESDAY NIGHT THROUGH FRIDAY AS A LOW PRESSURE SYSTEM TRAVERSES
THE AREA. TEMPERATURES THIS WEEK WILL BE NEAR TO ABOVE NORMAL WITH
HIGHS IN THE UPPER 70S TO 80S ALL WEEK. A COOL DOWN IS EXPECTED NEXT
WEEKEND BEHIND A COLD FRONT THAT MOVES THROUGH ON FRIDAY.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 1100 AM EDT MON SEP 1 2014
ISOLATED SEVERE WEATHER THREAT CONTINUES THIS AFTERNOON (2PM - 8PM)
EAST OF U.S. 131 WITH DAMAGING WIND GUSTS THE MAIN THREAT. BRIEF
LOCALIZED FLOODING TYPICAL OF STRONG THUNDERSTORMS IS ALSO POSSIBLE.
APPROACHING WEAK FRONTAL BOUNDARY...SEPARATING DEWPOINTS IN THE LOW
70S FROM THOSE IN THE MID 60S...IS CURRENTLY ORIENTED NORTH-SOUTH
ACROSS EASTERN WISCONSIN AND ILLINOIS. THERE IS ALSO CONSIDERABLE
CLOUDINESS ALONG AND AHEAD OF FRONT WHICH IS TEMPERATURES AND
DESTABILIZATION OFTHE AIRMASS.
THE FRONT WILL SWEEP EASTWARD ACROSS THE CWA THIS AFTERNOON AND
EARLY EVENING PROVIDING LOW LEVEL LIFT AND POTENTIAL FOCUS FOR
DEVELOPMENT OF NEW STORMS. ALOFT HOWEVER...THE LEAD SHORTWAVE AND
NOSE OF UPPER JET WILL PUSH EASTWARD OVER THE REGION WITH BEST DEEP
LIFT NORTH MAINLY NORTH OF THE AREA.
INSTABILITY AND WIND FIELDS ARE FAVORABLE FOR SEVERE STORMS WITH
CAPE VALUES OF 500 - 1500 J/KG...0-6 KM BULK SHEAR VALUES NEAR 40
KTS...AND 0-1KM SHEAR VALUES AROUND 20 KTS. HOWEVER...LACK OF DEEP
LIFT WILL LIMIT COVERAGE OF STORMS AND OVERALL SEVERE THEAT
SIGNICANTLY. THIS SOLUTION IS REFLECTED IN MANY OF THE HIGHER
RESOLUTION CONVECTION ALLOWING MODELS INCLUDING LAST FEW NSSL WRF
AND HRRR RUNS.
OTHERWISE...THE SHORT TERM IS RELATIVELY QUIET. ANY STORMS THIS
EVENING SHOULD WORK SOUTH OF THE AREA OVERNIGHT. NOT OUT OF THE
REALM OF POSSIBILITIES FOR A FEW SHOWERS ON TUESDAY...BUT FELT THE
THREAT WAS SMALL ENOUGH TO GO DRY. TUESDAY NIGHT AND WEDNESDAY
SHOULD BE DRY WITH RIDGING IN PLACE AT THE SURFACE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM EDT MON SEP 1 2014
THE MOST UNSETTLED WEATHER IN THE LONG TERM LOOKS TO OCCUR IN THE
FIRST COUPLE OF DAYS...FROM THE BEGINNING OF THE PERIOD WED NIGHT
INTO FRI NIGHT. THE LATEST TREND IS FOR A LITTLE MORE POSSIBLE PCPN
WED NIGHT INTO THU WITH THE PASSAGE OF THE WARM FRONT THROUGH THE
AREA. THIS LOOKS TO BE THE CASE DUE TO THE GRADIENT/LOW LEVEL JET
EXPECTED TO BE A LITTLE STRONGER WITH A STRONGER TROUGH MOVING IN.
HOW QUICKLY THE FRONT MOVES THROUGH WILL DICTATE HOW WARM WE GET ON
THU. IF THE FRONT MOVES QUICK ENOUGH...WE COULD HAVE A CHC TO WARM
TOWARD 90 WITH H850 TEMPS OF 20C ADVECTING IN. FOR NOW...WE HAVE
SETTLED WITH THE MID-UPPER 80S WITH THE UNCERTAINTY OF THE PCPN.
WE WILL SEE ANOTHER BATCH OF CONVECTION BE POSSIBLE THEN CENTERED
AROUND FRI AS THE COLD FRONT PUSHES THROUGH AND ENCOUNTERING THE
VERY WARM AND MOIST AIR MASS. WE COULD HAVE SOME ASSISTANCE VIA THE
RRQ OF AN UPPER JET TO OUR N/NE THAT WOULD SUPPLEMENT THE COLD
FRONTAL PASSAGE.
THE REMAINDER OF THE LONG TERM FROM SAT THROUGH SUN LOOKS TO BE
RATHER QUIET...YET COOL. WE WILL SEE A CANADIAN AIR MASS FILTER IN
BEHIND THE THU/FRI SYSTEM WITH A DECENT NNE LOW LEVEL FLOW USHERING
IT IN. THE UPPER FLOW WILL BE FROM THE NW AND A BIT OF A TROUGH WILL
BE OVER THE AREA. THE FAR ERN FLANK OF A SFC RIDGE WILL BE
BUILDING IN AS THE SYNOPTIC PATTERN OVER THE COUNTRY WILL FEATURE A
FAIRLY BROAD/EXPANSIVE UPPER RIDGE FROM THE ERN PACIFIC INTO THE
ROCKIES. THIS SHOULD KEEP THE AREA DRY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 749 AM EDT MON SEP 1 2014
COMPLICATED WEATHER SCENARIO IN PLACE THIS MORNING WITH STRATUS
MOVING NORTH THROUGH THE TAF SITES AND THE POTENTIAL FOR
THUNDERSTORMS LOOMING.
THE STRATUS AND FOG SHOULD GRADUALLY LIFT THROUGH THE COURSE OF
THE MORNING...BUT IT HAS BECOME FAIRLY EXTENSIVE ACROSS SOUTHERN
LOWER MICHIGAN. BY AFTERNOON...EXPECTING VFR CEILINGS AND VSBYS
OUTSIDE OF THUNDERSTORMS.
AS FOR THUNDERSTORMS...THEY ARE ALREADY DEVELOPING ACROSS
PORTIONS OF NORTHERN ILLINOIS AND NORTHERN INDIANA. THE TREND
SHOULD BE FOR SCATTERED SHOWERS AND THUNDERSTORMS TO MOVE THROUGH
THE TAF SITES FROM 14Z OR SO THROUGH 23Z. TOO DIFFICULT TO NAIL
DOWN PREVAILING TIMING AT THIS POINT GIVEN THE HIT OR MISS NATURE
TO TODAY/S STORMS...SO HAVE VCTS WORDING IN ALL THE TAFS THIS
AFTERNOON.
OVERNIGHT...EXPECTING THE SHOWERS AND STORMS TO END WITH MVFR
CEILINGS TRYING TO SETTLE BACK IN.
IT WILL BECOME WINDY TODAY OUT OF THE SOUTH-SOUTHWEST...ESPECIALLY
FROM 15Z-23Z. WINDS FROM 200-220 AT 15-25 KNOTS SHOULD BE COMMON.
&&
.MARINE...
ISSUED AT 1100 AM EDT MON SEP 1 2014
SCA/BEACH HAZARD WORKING WELL WITHWIND GUSTS NEAR 30 KTS AND WAVE
AROUND 4 FT OBSERVED NORTH OF HOLLAND TOWARDS LUDINGTON AT THIS
TIME. WINDS WILL CONTINUE NEXT SEVERAL HOURS WITH WAVES UP TO 5
FEET. WINDS / WAVES WILL SUBSIDE QUICKLY LATE THIS AFTERNOON WITH
PASSAGE OF FRONT AND SHIFT OF WINDS TO A MORE WESTERLY DIRECTION.
THE NEXT POSSIBLE SET OF HEADLINES THAT MAY BE NEEDED FOR THE
NEARSHORE WATERS LOOKS TO START IN THE WED NIGHT/THU TIME FRAME AS
THE FLOW STRENGTHENS WITH A SURGE OF WARMER AIR WITH THE NEXT
FRONTAL SYSTEM POISED TO MOVE IN.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT MON SEP 1 2014
LOCALLY HEAVY RAIN IS CERTAINLY POSSIBLE TODAY GIVEN PRECIPITABLE
WATER VALUES SURGING TOWARDS 2 INCHES THIS AFTERNOON. THE RAIN WILL
BE CONVECTIVE IN NATURE THOUGH...SO ANY HEAVY RAIN WILL OCCUR IN
SWATHS AS OPPOSED TO BEING WIDESPREAD. RIVER LEVELS ARE ALL WITHIN
BANK...AND FORECAST BASIN AVERAGE RAINFALL AMOUNTS ARE ON THE ORDER
OF 0.20 TO 0.50 INCHES. THESE AMOUNTS SHOULD BE ABLE TO BE ABSORBED
BY THE RIVER SYSTEMS WITHOUT MUCH ISSUE.
TODAY/S ISSUE THOUGH WILL BE MONITORING THE SWATHS OF HEAVIER RAIN
THAT SWEEP THROUGH WITH THE STORMS. THINKING THE MOTION WILL BE
QUICK ENOUGH (NORTHEAST AT 35-45 MPH)...TO PREVENT MUCH OF AN ISSUE
WITH FLASH FLOODING.
NEXT GOOD CHANCE FOR RAIN WILL COME LATER THIS WEEK WITH A WARM
FRONT WEDNESDAY NIGHT INTO THURSDAY MORNING AND AGAIN FRIDAY AHEAD
OF A COLD FRONT. TOTAL RAINFALL WITH THIS SYSTEM COULD BE ON THE
ORDER OF A HALF INCH TO AN INCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR MIZ037-043-050-
056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR
LMZ844>849.
&&
$$
SYNOPSIS...DUKE
SHORT TERM...COBB
LONG TERM...NJJ
AVIATION...DUKE
HYDROLOGY...DUKE
MARINE...COBB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
744 AM EDT MON SEP 1 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 510 AM EDT MON SEP 1 2014
WV IMAGERY AND RUC INDICATED A BROAD MID/UPPER LEVEL TROUGH FROM THE
ROCKIES INTO THE NRN/CNTRL PLAINS. AT THE SFC...A COLD FRONT
EXTENDED FROM NEAR INL THROUGH CNTRL MN INTO NW IA. A WEAK SHRTWV
FROM NE MN INTO NW WI SUPPORTED AN AREA OF SHOWERS AND ISOLD TSRA
OVER ERN MN INTO NW WI AND LAKE SUPERIOR. A STRONGER SHRTWV WAS
LOCATED OVER SW MN INTO NW IA. WITH ONLY MODEST 500-1000 J/KG
MUCAPE...ONLY A FEW TSRA WERE NOTED OVER THE REGION. THE MORE ACTIVE
CONVECTION OVER ERN LAKE SUPERIOR WAS ASSOCIATED WITH AN AREA OF
STRONGER 850 THETA-E ADVECTION AT THE NOSE OF THE LLJ.
TODAY...AS THE NW IA SHRTWV LIFTS TOWARD THE AREA WITH MODERATE
700-300 MB QVECTOR CONV AND THE COLD FRONT APPROACHES THE
AREA...EXPECT SHRA/TSRA COVERAGE TO INCREASE THIS MORNING. EVEN WITH
0-1KM/0-6KM SHEAR AROUND 40 KNOTS...SINCE INSTABILITY WILL REMAIN
LIMITED...MAINLY JUST BRIEF HEAVY RAIN IS EXPECTED. OVERALL RAINFALL
AMOUNTS SHOULD BE LIMITED GIVEN THE QUICK MOVEMENT OF THE CONVECTIVE
CELLS AND LACK OF LARGE SCALE ORGANIZATION. THE PCPN WILL DIMINISH
FROM WEST TO EAST THIS AFTERNOON AS THE COLD FRONT MOVES THROUGH AND
QVECTOR DIV SPREADS INTO UPPER MI IN THE WAKE OF THE SHRTWV. CLOUD
COVER WILL KEEP HIGH TEMPS NEAR OR SLIGHTLY BELOW SEASONAL AVERAGES
IN THE UPPER 60S TO AROUND 70.
TONIGHT...ANY LINGERING PCPN OVER THE ERN CWA IN THE EVENING WILL
END EARLY. OTHERWISE...A DRIER AIRMASS MOVING INTO THE AREA WITH
DEWPOINTS DROPPING TOWARD THE LOWER 50S WILL ALLOW TEMPS TO ALSO
DROP INTO THE LOWER TO MID 50S AS SKIES PARTIALLY CLEAR. AN INCREASE
IN CLOUD COVER IS EXPECTED LATE OVER THE SW CWA AHEAD OF THE NEXT
WEAK SHRTWV.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 321 AM EDT MON SEP 1 2014
IN THE WAKE OF STRONGER SHORTWAVE AND SFC FRONT MOVING THROUGH
TODAY...ANOTHER SHORTWAVE CLIPS ACROSS THE AREA ON TUESDAY IN
INCREASINGLY ZONAL FLOW ALOFT. MOISTURE IS LIMITED WITH THE WAVE AS
SOUNDINGS ONLY SHOW MOISTURE H8-H7. PRETTY HIGH BASED SHRA AND WILL
ALSO MENTION ISOLD TSRA WITH MLCAPE 500-1000 J/KG PER ECMWF AND GFS.
WILL INCLUDE SLIGHT CHANCE POPS. A LULL FOR TUE NIGHT AS SFC RIDGE
MOVES FROM MIDDLE MISSISSIPPI RIVER VALLEY TO THE OHIO VALLEY. LGT
SW WINDS ON PERIFERY OF THE RIDGE WILL LIMIT COOLING. LOWEST PWAT
FAR EAST CWA WHERE MIN TEMPS MAY FALL TO AROUND 50 DEGREES. ON
WEDNESDAY...GFS AND GEM-NH INDICATE SOME SHOWERS COULD OCCUR IN THE
AFTN OVER MAINLY THE WEST HALF CWA. WEAK SHORTWAVE IS THERE BUT ONLY
APPEARS THAT BEST MOISTURE INFLOW IS OVER FAR WEST CWA. WARM AIR
ADVECTION BOOSTS H85 TEMPS TO AROUND +15C SO AS LONG AS SKIES STAY
AT LEAST PARTLY CLOUDY...MAX TEMPS WILL TOP OUT IN THE MID 70S TO
LOWER 80S.
LATER WEDNESDAY NIGHT INTO THURSDAY MORNING LARGER SCALE LIFT
AHEAD OF UPPER TROUGH INCREASES OVER NORTHERN PLAINS AND WESTERN
GREAT LAKES. LIKELY WILL BE SOME SHORTWAVES SLIDING OUT OF NORTHERN
PLAINS AS WELL...THOUGH RIGHT NOW SIGNAL OF ANY STRONGER SHORTWAVE
IS MINIMAL. THERE IS A MID LEVEL JET MAX SLIDING OVER THE AREA AND
H85-H5 Q-VECTOR CONVERGENCE WILL BE ON THE INCREASE. PRIMARY SFC
TROUGH WILL BE OVER MINNESOTA AND BASED ON SFC WINDS AND
DWPNTS...THERE WILL BE A WARM FRONT VCNTY OF SOUTHERN/CENTRAL
MINNESOTA INTO WESTERN WISCONSIN. BULGE OF WARMTH ALOFT RESULTS IN
AN ELEVATED MIXED LAYER WITH H7-H5 LAPSE RATES OVER 8C/KM MAKING IT
OVER UPR LAKES AHEAD OF THE SFC TROUGH. RESERVOIR OF ML MUCAPE OVER
2000J/KG WILL BE JUST SOUTHWEST OF UPR MICHIGAN WITH MID LEVEL FLOW
SW-NE. EDGE OF SFC BASED CAPE AND ORIENTATION OF H85-H3 THICKNESSES
INDICATE THAT STRONGER STORMS MAY BE MORE TO SOUTHWEST OF UPR
MICHIGAN LATER WEDNESDAY NIGHT INTO THURSDAY MORNING. TOUGH TO SAY
AT THIS POINT THOUGH. CONSENSUS CHANCE POPS WORK FOR NOW SINCE THERE
WILL BE LARGE SCALE WARM AIR ADVECTION AND H85-H7 MOISTURE TRANSPORT
AIMED INTO THE AREA. MORE SHRA/TSRA POSSIBLE AS SFC FRONT WORKS
ACROSS UPR MICHIGAN LATER ON THURSDAY. PLENTY OF INSTABILITY AS
TEMPS IN THE SOUTH-SOUTHWEST FLOW AHEAD OF FRONT SHOULD REACH TOWARD
80 DEGREES WITH EVEN A FEW HOURS OF PARTIAL CLEARING SINCE H85 TEMPS
ARE 18-20C. MOISTURE AVAILABILITY/MID LEVEL CAPPING ALONG THE FRONT
REMAINS A CONCERN FOR COVERAGE OF SFC BASED STORMS IN THE AFTN. MODELS
MAY BE PICKING UP ON THIS AS GFS/ECMWF SHOW A MIN IN QPF 18Z-24Z BUT
THEN INCREASE IT BY 06Z ON FRIDAY AS FRONT WILL MAINLY BE SOUTH AND
EAST OF CWA BY THAT TIME. NO NEED TO GET TOO FANCY WITH THE GRIDS
ATTM GIVEN ALL THE UNCERTAINTY. KEPT WITH THE CONSENSUS CHANCE POPS
ON THURSDAY WITH THIS DROPPING OFF TO LOWER CHANCES THURSDAY NIGHT
CLOSER TO THE DEPARTING FRONT.
REST OF THE FORECAST LOOKS DRY AND COOLER AS HIGH PRESSURE BUILDS IN
ON FRIDAY AND WILL HOLD ON THROUGH NEXT WEEKEND. MAX TEMPS IN THE
MID 60S TO LOWER 70S. CHILLY LOWS POSSIBLE INLAND BOTH FRIDAY NIGHT
AND SATURDAY NIGHT DUE TO THE DRY AIRMASS AND LGT WINDS BENEATH THE
HIGH PRESSURE. BIAS CORRECTED GUIDANCES SHOWED MINS IN THE LOWER 40S
BUT WOULD NOT BE SURPRISED TO SEE READINGS DIPPING INTO THE 30S
EITHER OF THOSE NIGHTS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 743 AM EDT MON SEP 1 2014
IWD...ALTHOUGH THERE MAY BE SOME BREAKS IN THE SHRA...MVFR
CONDITIONS WL PREDOMINATE EARLY. THE CIGS ARE LIKELY TO FALL INTO THE IFR
RANGE BRIEFLY DURING MID MRNG AS THE FRONT PASSES AND THE WIND SHIFTS
TO AN UPSLOPE WNW DIRECTION. THE W WIND BEHIND THE FROPA WILL TAP
DRIER AIR AND ALLOW FOR CONDITIONS TO IMPROVE TO VFR DURING THE AFTN.
CMX...MVFR CONDITIONS WILL PREDOMINATE EARLY WITH PERIODS OF SHOWERS.
A WSHFT TO AN UPSLOPE W DIRECTION BEHIND A FROPA AND WITH SOME
CONTINUED -SHRA SHOULD RESULT IN A PERIOD OF IFR CONDITIONS DURING THE
LATE MRNG/EARLY AFTN BEFORE THE W WIND TAPS DRIER AIR AND RESULTS IN
IMPROVEMENT TO VFR BY LATE IN THE DAY.
SAW...EXPECT IFR CIGS TO PERSIST THIS MORNING WITH ABUNDANT LOW
LEVEL MOISTURE AND UPSLOPE SRLY FLOW. EXPECT SOME SHRA WITH MVFR
CONDITIONS TO DEVELOPP BY LATE MORNING WITH THE APPROACH OF A SFC
COLD FRONT. EXPECT IMPROVEMENT LATE IN THE AFTERNOON WITH A WSHFT TO
A DOWNSLOPE W DIRECTION AND THE ARRIVAL OF DRIER AIR FOLLOWING THE
FROPA.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 510 AM EDT MON SEP 1 2014
WINDS WILL BE 20 KNOTS OR LESS THROUGH THIS FORECAST PERIOD WITH
AREAS OF FOG PERSISTING UNTIL DRIER AIR MOVES INTO THE REGION
TONIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
515 AM EDT MON SEP 1 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 510 AM EDT MON SEP 1 2014
WV IMAGERY AND RUC INDICATED A BROAD MID/UPPER LEVEL TROUGH FROM THE
ROCKIES INTO THE NRN/CNTRL PLAINS. AT THE SFC...A COLD FRONT
EXTENDED FROM NEAR INL THROUGH CNTRL MN INTO NW IA. A WEAK SHRTWV
FROM NE MN INTO NW WI SUPPORTED AN AREA OF SHOWERS AND ISOLD TSRA
OVER ERN MN INTO NW WI AND LAKE SUPERIOR. A STRONGER SHRTWV WAS
LOCATED OVER SW MN INTO NW IA. WITH ONLY MODEST 500-1000 J/KG
MUCAPE...ONLY A FEW TSRA WERE NOTED OVER THE REGION. THE MORE ACTIVE
CONVECTION OVER ERN LAKE SUPERIOR WAS ASSOCIATED WITH AN AREA OF
STRONGER 850 THETA-E ADVECTION AT THE NOSE OF THE LLJ.
TODAY...AS THE NW IA SHRTWV LIFTS TOWARD THE AREA WITH MODERATE
700-300 MB QVECTOR CONV AND THE COLD FRONT APPROACHES THE
AREA...EXPECT SHRA/TSRA COVERAGE TO INCREASE THIS MORNING. EVEN WITH
0-1KM/0-6KM SHEAR AROUND 40 KNOTS...SINCE INSTABILITY WILL REMAIN
LIMITED...MAINLY JUST BRIEF HEAVY RAIN IS EXPECTED. OVERALL RAINFALL
AMOUNTS SHOULD BE LIMITED GIVEN THE QUICK MOVEMENT OF THE CONVECTIVE
CELLS AND LACK OF LARGE SCALE ORGANIZATION. THE PCPN WILL DIMINISH
FROM WEST TO EAST THIS AFTERNOON AS THE COLD FRONT MOVES THROUGH AND
QVECTOR DIV SPREADS INTO UPPER MI IN THE WAKE OF THE SHRTWV. CLOUD
COVER WILL KEEP HIGH TEMPS NEAR OR SLIGHTLY BELOW SEASONAL AVERAGES
IN THE UPPER 60S TO AROUND 70.
TONIGHT...ANY LINGERING PCPN OVER THE ERN CWA IN THE EVENING WILL
END EARLY. OTHERWISE...A DRIER AIRMASS MOVING INTO THE AREA WITH
DEWPOINTS DROPPING TOWARD THE LOWER 50S WILL ALLOW TEMPS TO ALSO
DROP INTO THE LOWER TO MID 50S AS SKIES PARTIALLY CLEAR. AN INCREASE
IN CLOUD COVER IS EXPECTED LATE OVER THE SW CWA AHEAD OF THE NEXT
WEAK SHRTWV.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 321 AM EDT MON SEP 1 2014
IN THE WAKE OF STRONGER SHORTWAVE AND SFC FRONT MOVING THROUGH
TODAY...ANOTHER SHORTWAVE CLIPS ACROSS THE AREA ON TUESDAY IN
INCREASINGLY ZONAL FLOW ALOFT. MOISTURE IS LIMITED WITH THE WAVE AS
SOUNDINGS ONLY SHOW MOISTURE H8-H7. PRETTY HIGH BASED SHRA AND WILL
ALSO MENTION ISOLD TSRA WITH MLCAPE 500-1000 J/KG PER ECMWF AND GFS.
WILL INCLUDE SLIGHT CHANCE POPS. A LULL FOR TUE NIGHT AS SFC RIDGE
MOVES FROM MIDDLE MISSISSIPPI RIVER VALLEY TO THE OHIO VALLEY. LGT
SW WINDS ON PERIFERY OF THE RIDGE WILL LIMIT COOLING. LOWEST PWAT
FAR EAST CWA WHERE MIN TEMPS MAY FALL TO AROUND 50 DEGREES. ON
WEDNESDAY...GFS AND GEM-NH INDICATE SOME SHOWERS COULD OCCUR IN THE
AFTN OVER MAINLY THE WEST HALF CWA. WEAK SHORTWAVE IS THERE BUT ONLY
APPEARS THAT BEST MOISTURE INFLOW IS OVER FAR WEST CWA. WARM AIR
ADVECTION BOOSTS H85 TEMPS TO AROUND +15C SO AS LONG AS SKIES STAY
AT LEAST PARTLY CLOUDY...MAX TEMPS WILL TOP OUT IN THE MID 70S TO
LOWER 80S.
LATER WEDNESDAY NIGHT INTO THURSDAY MORNING LARGER SCALE LIFT
AHEAD OF UPPER TROUGH INCREASES OVER NORTHERN PLAINS AND WESTERN
GREAT LAKES. LIKELY WILL BE SOME SHORTWAVES SLIDING OUT OF NORTHERN
PLAINS AS WELL...THOUGH RIGHT NOW SIGNAL OF ANY STRONGER SHORTWAVE
IS MINIMAL. THERE IS A MID LEVEL JET MAX SLIDING OVER THE AREA AND
H85-H5 Q-VECTOR CONVERGENCE WILL BE ON THE INCREASE. PRIMARY SFC
TROUGH WILL BE OVER MINNESOTA AND BASED ON SFC WINDS AND
DWPNTS...THERE WILL BE A WARM FRONT VCNTY OF SOUTHERN/CENTRAL
MINNESOTA INTO WESTERN WISCONSIN. BULGE OF WARMTH ALOFT RESULTS IN
AN ELEVATED MIXED LAYER WITH H7-H5 LAPSE RATES OVER 8C/KM MAKING IT
OVER UPR LAKES AHEAD OF THE SFC TROUGH. RESERVOIR OF ML MUCAPE OVER
2000J/KG WILL BE JUST SOUTHWEST OF UPR MICHIGAN WITH MID LEVEL FLOW
SW-NE. EDGE OF SFC BASED CAPE AND ORIENTATION OF H85-H3 THICKNESSES
INDICATE THAT STRONGER STORMS MAY BE MORE TO SOUTHWEST OF UPR
MICHIGAN LATER WEDNESDAY NIGHT INTO THURSDAY MORNING. TOUGH TO SAY
AT THIS POINT THOUGH. CONSENSUS CHANCE POPS WORK FOR NOW SINCE THERE
WILL BE LARGE SCALE WARM AIR ADVECTION AND H85-H7 MOISTURE TRANSPORT
AIMED INTO THE AREA. MORE SHRA/TSRA POSSIBLE AS SFC FRONT WORKS
ACROSS UPR MICHIGAN LATER ON THURSDAY. PLENTY OF INSTABILITY AS
TEMPS IN THE SOUTH-SOUTHWEST FLOW AHEAD OF FRONT SHOULD REACH TOWARD
80 DEGREES WITH EVEN A FEW HOURS OF PARTIAL CLEARING SINCE H85 TEMPS
ARE 18-20C. MOISTURE AVAILABILITY/MID LEVEL CAPPING ALONG THE FRONT
REMAINS A CONCERN FOR COVERAGE OF SFC BASED STORMS IN THE AFTN. MODELS
MAY BE PICKING UP ON THIS AS GFS/ECMWF SHOW A MIN IN QPF 18Z-24Z BUT
THEN INCREASE IT BY 06Z ON FRIDAY AS FRONT WILL MAINLY BE SOUTH AND
EAST OF CWA BY THAT TIME. NO NEED TO GET TOO FANCY WITH THE GRIDS
ATTM GIVEN ALL THE UNCERTAINTY. KEPT WITH THE CONSENSUS CHANCE POPS
ON THURSDAY WITH THIS DROPPING OFF TO LOWER CHANCES THURSDAY NIGHT
CLOSER TO THE DEPARTING FRONT.
REST OF THE FORECAST LOOKS DRY AND COOLER AS HIGH PRESSURE BUILDS IN
ON FRIDAY AND WILL HOLD ON THROUGH NEXT WEEKEND. MAX TEMPS IN THE
MID 60S TO LOWER 70S. CHILLY LOWS POSSIBLE INLAND BOTH FRIDAY NIGHT
AND SATURDAY NIGHT DUE TO THE DRY AIRMASS AND LGT WINDS BENEATH THE
HIGH PRESSURE. BIAS CORRECTED GUIDANCES SHOWED MINS IN THE LOWER 40S
BUT WOULD NOT BE SURPRISED TO SEE READINGS DIPPING INTO THE 30S
EITHER OF THOSE NIGHTS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 132 AM EDT MON SEP 1 2014
IWD...LLWS AND NMRS HEAVY SHRA WITH SOME EMBEDDED TS RIDING NNEWD
UNDER A STRONG SSW LLJ IN ADVANCE OF A SLOW MOVING COLD FNT WILL
IMPACT THIS SITE THRU SUNRISE. ALTHOUGH THERE MAY BE SOME BREAKS IN
THE HEAVIER SHRA...MVFR CONDITIONS WL PREDOMINATE. THE CIGS ARE
LIKELY TO FALL INTO THE IFR RANGE BRIEFLY DURING MID MRNG AS THE FNT
PASSES AND THE WIND SHIFTS TO AN UPSLOPE WNW DIRECTION. THE W WIND
BEHIND THE FROPA WL TAP DRIER AIR AND ALLOW FOR CONDITIONS TO
IMPROVE TO VFR DURING THE AFTN.
CMX...VFR CONDITIONS WL DOMINATE EARLY IN THE TAF PERIOD BUT THEN
GIVE WAY TO MVFR WX AS A BAND OF MDT-HVY SHRA AHEAD OF THE SLOWLY
APRCHG COLD FNT EDGES SLOWLY TO THE E. LLWS WL BE THE RULE THRU
SUNRISE UNDER A STRONG SW LLJ. A WSHFT TO AN UPSLOPE W DIRECTION
BEHIND THE FROPA AND WITH SOME CONTINUED -SHRA WL RESULT IN A PERIOD
OF IFR CONDITIONS DURING THE LATE MRNG/EARLY AFTN BEFORE THE W WIND
TAPS DRIER AIR AND RESULTS IN IMPROVEMENT TO VFR BY LATE IN THE DAY.
SAW...EXPECT LO CLDS/IFR CIGS TO LINGER THRU THE NGT WITH A MOIST
SLY FLOW UNDER A STRONG SW LLJ SUFFICIENT TO CAUSE LLWS DRAWING LLVL
MSTR N FM LK MI IN THE PRESENCE OF DIURNAL COOLING. EXPECT SOME SHRA
WITH MVFR CONDITIONS TO DVLP BY LATE MRNG WITH THE CLOSER APRCH OF
SFC COLD FNT. EXPECT IMPROVEMENT LATE IN THE AFTN WITH A WSHFT TO A
DOWNSLOPE W DIRECTION AND ARRIVAL OF DRIER AIR FOLLOWING THE FROPA.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 510 AM EDT MON SEP 1 2014
WINDS WILL BE 20 KNOTS OR LESS THROUGH THIS FORECAST PERIOD WITH
AREAS OF FOG PERSISTING UNTIL DRIER AIR MOVES INTO THE REGION
TONIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
149 AM EDT MON SEP 1 2014
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 322 PM EDT SUN AUG 31 2014
A WEAK AREA OF HIGH PRESSURE WILL KEEP MUCH OF THE REGION DRY INTO
THE EVENING. A COLD FRONT WILL APPROACH FROM THE WEST ON LABOR DAY
TRIGGERING SHOWERS AND THUNDERSTORMS. HIGH PRESSURE WILL RETURN
FOR TUESDAY DRYING THE REGION OUT.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 322 PM EDT SUN AUG 31 2014
THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH THE POTENTIAL FOR
SEVERE WEATHER ON MONDAY. OVERALL THE POTENTIAL STILL EXISTS.
ONE POTENTIAL LIMITING FACTOR WILL BE WHAT IMPACTS THE DECAYING
AREA OF THUNDERSTORMS WILL HAVE AS IT MOVES IN FROM THE WEST
MONDAY MORNING. THE HRRR RUC SHOWS THIS SYSTEM WEAKENING WELL
BEFORE IT ARRIVES IN MI...SO I AM THINKING THIS WILL HAVE A
MINIMAL IMPACT ON THE POTENTIAL INSTABILITY MONDAY. THE
COMBINATION OF HEATING AND MOISTURE ADVECTION SUPPORTS CAPE OVER
1500 J/KG ON MONDAY. DEEP LAYER SHEAR INCREASES TOWARD 18Z AS THE
MID LEVEL WAVE CURRENTLY IN WI ARRIVES IN NW LOWER. THE LIFT
ASSOCIATED WITH THIS FEATURE SHOULD TRIGGER STORMS. THE SHEAR WILL
HELP TO INCREASE THE POTENTIAL FOR ORGANIZED CONVECTION AND
RESULTING SEVERE WEATHER. DAMAGING WINDS AND LARGE HAIL A THREAT.
SRH VALUES AROUND 200 M2/S2 DO SUPPORT A RISK FOR TORNADOES.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 322 PM EDT SUN AUG 31 2014
MEDIUM RANGE MODELS ARE IN DECENT AGREEMENT INTO NEXT WEEKEND...
HOWEVER THERE ARE TIMING DIFFERENCES WITH A STRONG COLD FRONT THAT
COMES THROUGH FRIDAY/FRIDAY NIGHT.
LARGE HIGH PRESSURE IS EXPECTED TO BE SITTING OVER THE EAST SEABOARD
BY MID WEEK. THIS WILL BRING WARMING SOUTHERLY FLOW TO THE GREAT
LAKES REGION. IT CONTINUES TO LOOK LIKE THURSDAY WILL BE THE
WARMEST DAY OF THE WEEK WITH 80S FOR HIGHS. THE RISK FOR SHOWERS
AND STORMS WILL INCREASE ON THURSDAY WITH A COLD FRONT MOVING INTO
THE WESTERN GREAT LAKES. WARM AND MOIST AIR WITH MOVE IN AHEAD OF
THIS FRONT. IF A LOW LEVEL JET COMES INTO PLAY WE COULD BE LOOKING
AT STRONG TO SEVERE STORMS TOWARD THE END OF THE DAY.
THERE CONTINUES TO BE TIMING DIFFERENCES WITH THE FRONT...BUT THE
GFS SLOWED THE FRONT DOWN...CLOSER TO THE WHAT THE ECMWF HAS SHOWN.
THEREFORE BELIEVE THE FRONT WILL BE COMING THROUGH ON FRIDAY WITH
ADDITIONAL CHANCES FOR SHOWERS AND STORMS. MUCH COOLER AIR FOLLOWS
THIS STRONG FRONT FOR FRIDAY NIGHT AND INTO NEXT WEEKEND. H8 TEMPS
DROP TO +7 TO +10C AS COMPARED TO AROUND +19C AHEAD OF THE COLD
FRONT. THE WEEKEND SHOULD FEATURE HIGHS IN THE UPPER 60S TO MID 70S
WITH MAINLY DRY WEATHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 149 AM EDT MON SEP 1 2014
THERE ARE A FEW ITEMS THAT COULD IMPACT AVIATION OPERATIONS OVER
THE NEXT 24 HOURS ACROSS SW LOWER MI. THE FIRST ITEM IS FOG
POTENTIAL. A DECENT AMOUNT OF LOW LEVEL MOISTURE REMAINS IN
PLACE THIS MORNING AND TEMPS AND DEW POINTS ARE CLOSE ALREADY. THE
BEST CHC FOR FOG AND SOME POSSIBLE STRATUS WILL BE ALONG AND SE OF
I-69 WHERE A FEW SHOWERS WERE PRESENT EARLIER AND WHERE THE
MOISTURE HAS HUNG IN THE MOST. CAN NOT RULE OUT SOME NEAR KGRR AND
KAZO...BUT THE FURTHER WEST THE WINDS WILL REMAIN UP AND LIMIT FOG POTENTIAL.
THE NEXT THING IS THE POTENTIAL FOR PCPN TODAY. MOST DATA
INDICATES THAT WHATEVER IS LEFT OF THE LINE OF SHOWERS/STORMS NEAR
THE MISSISSIPPI RIVER AS OF 0545Z WILL MOVE INTO THE AREA
TOWARD 15Z OR SO. IT WILL INITIALLY FALL APART WITH LESS CHC OF
IMPACTS FROM IT TOWARD THE LAKESHORE. AS IT ENCOUNTERS SOME
DIURNAL INSTABILITY TOWARD THE EAST...WE EXPECT IT TO REINTENSIFY
INTO A LINE OF STORMS BY THE TIME IT REACHES U.S.-127 BY 19Z OR
SO. BEST CHC FOR LOWER CONDITIONS WILL BE ACROSS THE EAST WHERE
IFR WOULD BE LIKELY IN HEAVY RAINFALL. THIS CAN BE FINE TUNED
CLOSER TO THE EVENT.
ONCE THE LINE OF STORMS MOVES EAST...THERE SHOULD BE SOMEWHAT OF A
BREAK. ANOTHER PERIOD OF SOME SHOWERS WILL BE POSSIBLE WITH THE
WAVE TOWARD 00Z AND AFTER THAT.
&&
.MARINE...
ISSUED AT 322 PM EDT SUN AUG 31 2014
BEACH HAZARDS AND SCA ISSUED FOR MONDAY
&&
.HYDROLOGY...
ISSUED AT 322 PM EDT SUN AUG 31 2014
HIGH PWAT VALUES SUPPORT LOCALLY HEAVY RAIN ON MONDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT FROM 10 AM EDT THIS MORNING THROUGH THIS
EVENING FOR MIZ037-043-050-056-064-071.
LM...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 10 PM EDT THIS
EVENING FOR LMZ844>849.
&&
$$
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...JK
AVIATION...NJJ
HYDROLOGY...MJS
MARINE...MJS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
447 AM CDT MON SEP 1 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT MON SEP 1 2014
A FAIRLY BROAD LONGWAVE TROUGH WAS SETTING UP THIS MORNING FROM THE
GREAT LAKES BACK TO THE PAC NW. THE MAIN PIECE OF ENERGY EMBEDDED
WITHIN THIS TROUGH IS THE TROUGH WORKING INTO WRN IA/SRN MN THIS
MORNING. THERE IS A FAIRLY POTENT SHORTWAVE WITHIN THIS TROUGH NEAR
SIOUX FALLS...AS EVIDENCE BY THE NICE SPIN SEEN WITHIN THE KFSD
REFLECTIVITY. AT THE SFC...A BROAD FRONTAL TROUGH WAS SITUATED
ACROSS MN...THOUGH THE WIND SHIFT AND T/TD DROP YOU COULD ASSOCIATE
WITH THE MAIN FRONT WAS SITUATED FROM ABOUT CANBY UP TO
INTERNATIONAL FALLS. 8Z SPC MESO ANALYSIS STILL SHOWED ABOUT 500
J/KG OF SBCAPE OUT AHEAD OF THIS BOUNDARY. THIS INSTABILITY COMBINED
WITH LIFT FROM THE WAVE NEAR SIOUX FALLS EXPLAINS WHY WE HAVE
CONTINUED TO SEE NEW CONVECTION DEVELOP THROUGH THE NIGHT OUT IN WRN
MN. ALTHOUGH NONE OF THE CAMS HAVE HANDLED THIS TRAILING ACTIVITY
WELL...THE LOCAL WRF HAS HANDLED IT THE BEST THIS MORNING...SO
FOLLOWED IT FOR SLOWLY DRAGGING POPS ACROSS THE AREA THIS MORNING.
LOOKS LIKE IT WILL TAKE UNTIL BETWEEN 15 AND 18Z TO COMPLETELY CLEAR
THIS ACTIVITY OUT OF WRN WI. DUE TO LIMITED INSTABILITY...THE SEVERE
POTENTIAL WITH THIS ACTIVITY WILL ESSENTIALLY BE NIL...BUT WE WILL
CONTINUE TO SEE HEAVY DOWNPOURS...WITH A QUICK HALF TO ONE INCH OF
RAIN LIKELY FOR AREAS THAT GET UNDER HEAVIER RAIN CORES.
BEHIND THIS SYSTEM SKIES WILL CLEAR OUT FOR A BIT...BUT BY THE
AFTERNOON...TROUGH AXIS CURRENTLY SITUATED FROM SASKATCHEWAN DOWN
INTO ERN IDAHO WILL BE SPREADING MID CLOUDS INTO WRN MN AS IT
QUICKLY TRACKS ACROSS THE DAKOTAS WITHIN A MODERATELY FAST ZONAL
FLOW. WILL LIKELY SEE SOME SCATTERED DIURNALLY DRIVEN ACTIVITY
DEVELOP ACROSS THE DAKOTAS AHEAD OF THE WAVE THAT WILL MAKE A RUN
FOR WRN MN EARLY THIS EVENING BEFORE WE LOSE DAYTIME HEATING. AS A
RESULT...REMOVED POPS AFTER 3Z. THALER QG DIAGNOSTICS SHOWS
SUBSIDENCE DOMINATING MN/WI TONIGHT AND WITH THE LOSS OF DIURNAL
HEATING...ALL CAMS SHOW ACTIVITY DISSIPATING. ALTHOUGH THE NAM/GFS
CONTINUE TO SHOW SOME LIGHT QPF ACROSS MN THROUGH THE
NIGHT...DECIDED TO SIDE MORE TOWARD THE FORCING THAN MODEL GENERATED
QPF IN GOING WITH THE DRY FORECAST AFTER 3Z.
FOR HIGHS TODAY...DO EXPECT A DESCENT AMOUNT OF SUNSHINE FOR THE
LATE MORNING THROUGH MUCH OF THE AFTERNOON...WITH H85 TEMPS EXPECTED
TO BE A COUPLE OF DEGREES ON EITHER SIDE OF 16C. BUFKIT SOUNDINGS
SHOW US MIXING UP TO ABOUT 825 AND MIXING THOSE TEMPERATURES DOWN TO
THE SFC ON THE NAM SPIT BACK OUT HIGHS IN THE MID/UPPER 70S...SO DID
NUDGE HIGHS UP A FEW DEGREES...WHICH SIMPLY PUT US TOWARD THE HIGHER
END OF THE GUIDANCE ENVELOP.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 340 AM CDT MON SEP 1 2014
SIGNS OF EARLY FALL ARE IN THE AIR WITH A PERSISTENT WEST COAST
TROUGH AND WESTERLY FLOW ACROSS THE UPPER MISSISSIPPI THROUGH THE
EXTENDED. THERE ARE ALSO A STRONG COLD FRONTS EXPECTED OVER THE NEXT
7-10 DAYS PRECEDED BY BRIEF BOUTS OF WARMTH AND INCREASED
HUMIDITY.
TUESDAY SHOULD FEATURE QUIET AND PLEASANT WEATHER WITH MID-LEVEL
HEIGHT RISES...AND SURFACE RIDGING JUST SOUTH OF THE FORECAST AREA.
WARM AIR ADVECTION SHOULD BEGIN IN EARNEST BY TUESDAY AFTERNOON AS
WARMER AIR FROM THE PLAINS REPLACES THE COOLER AIR MASS TIED TO
MONDAY`S TROUGH. WEDNESDAY LOOKS LIKE THE MOST INTERESTING DAY OF
THE UPCOMING WEEK IN TERMS OF THUNDER POTENTIAL AND EVEN SMALL
PROBABILITIES FOR SEVERE WEATHER IN MN. A FAST MOVING UPPER WAVE
WILL MOVE FROM THE PACIFIC NORTHWEST TO NEARLY HUDSON BAY IN
APPROXIMATELY 48 HOURS. A SURFACE LOW IS EXPECTED TO DEVELOP IN THE
DAKOTAS AND MOVE INTO NW MN BY 12Z THURSDAY. THE LOCATION OF THE
ASSOCIATED WARM FRONT SHOULD FOCUS A MAJORITY OF THE CONVECTION
ACROSS THE NORTHERN HALF OF MN...WITH THE 01.00Z GFS/NAM/ECMWF
KEEPING QPF BULLS EYE NORTH OF I-94. THERE IS THE POTENTIAL FOR
STRONG TO SEVERE STORMS NEAR THE WARM FRONT. BOTH THE GFS/NAM
GENERATE 2000-2500J/KG OF MUCAPE BY 21-00Z WEDNESDAY. THERE IS ALSO
DECENT FLOW ALOFT WITH 30-40KTS OF DEEP LAYER SHEER AND A VEERING
HODOGRAPH. SOUTH OF THE MOST ROBUST CONVECTION...IT SHOULD BE WARM
AND STEAMY. WARMEST PLUME OF 850MB ARRIVES THURSDAY
MORNING...SETTING UP ANOTHER POTENTIALLY WARM AND HUMID DAY IN THE
EASTERN FORECAST AREA ON THURSDAY. BOTH WEDNESDAY AND THURSDAY COULD
FEATURE A LOT OF HEAT INDICES IN THE UPPER 80S AND LOWER 90S. A
STRONG COLD FRONT PASSES THROUGH BY FRIDAY AND WILL RESULT IN A DRY
AND COOLER WEEKEND UNDER HIGH PRESSURE. SO IT LOOKS A FAIRLY QUIET
EXTENDED UNTIL PERHAPS THE MIDDLE OF NEXT WEEK WHEN ANOTHER BRIEF
WARM-UP AND SHARP COLD FRONT ARE SHOWING UP OFF THE GFS AND ECMWF.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1219 AM CDT MON SEP 1 2014
THUNDER THREAT LARGELY DONE ACROSS THE MPX AIRSPACE...BUT STRONG
UPPER WAVE BACK BY SIOUX FALLS STILL HAS TO WORK ACROSS SRN MN/WRN
WI TONIGHT...WHICH WILL KEEP SCT SHOWERS GOING THROUGH MUCH OF THE
NIGHT...AS WE ARE SEEING WITH THE HRRR. BIGGER QUESTION MARK
REVOLVES AROUND STRATUS/FOG POTENTIAL TONIGHT. CERTAINLY THIS
STRATIFORM RAIN WE ARE SEE OUT THERE NOW WILL HELP MOISTEN THE
ATMO AND INCREASE THE THREAT FOR STRATUS...BUT CIGS AT THE START
ARE LARGELY UP AROUND 10K FT...SO WE HAVE A WAYS TO GO. FOLLOWED
THE IDEA OF THE RAP THOUGH WITH STATUS EVENTUALLY FILLING IN
WITHIN AND EAST OF THE WEAKENING SFC TROUGH...WHICH AT 6Z
STRETCHED FROM ABOUT NEW ULM TO MILLE LACS LAKE. THIS MOISTURE
LOOKS TO GET SCOURED OUT PRETTY QUICK BY WNW WINDS IN THE
MORNING...WITH MOST OF LABOR DAY GOING BY WITH VFR CONDS. DURING
THE LATE AFTERNOON...ANOTHER UPPER WAVE WILL BE COMING OUT OF THE
DAKOTAS...BUT IT LOOKS TO DO NOTHING MORE THAN PROVIDE US WITH AN
INCREASE IN MID CLOUDS AND PERHAPS A FEW SPRINKLES AS WE HEAD INTO
MONDAY NIGHT.
KMSP...STRATIFORM RAIN WE ARE SEEING NOW FAVORED ME TOWARD KEEPING
THE DEVELOPMENT OF SUB 018 CIGS WE HAD IN THE TAF...BUT WITH CIGS
STILL ABOVE 5K FT...NOT COMPLETELY SOLD ON THOSE RESTRICTIONS
HAPPENING. OTHER THAN THAT...NO OTHER CONCERNS ARE EXPECTED THIS
PERIOD.
/OUTLOOK FOR KMSP/
TUE...VFR. WINDS WSW 5-10 KTS.
WED...VFR. CHC MVFR/TSRA LATE. WINDS S 5-10 KTS.
THU...VFR. CHC MVFR/TSRA. WINDS S BCMG W 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...CLF
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1233 AM CDT MON SEP 1 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 252 PM CDT SUN AUG 31 2014
SVR WX PARAMETERS REMAIN FAVORABLE FOR LARGE HAIL/DAMAGING WINDS
THIS AFTN/EARLY EVENING. THE MAIN PROBLEM IS AFTN CAP /BASED ON
18Z KMPX SOUNDING/ WHICH HAS SUPPRESSED MOST OF THE CONVECTION
ACROSS SOUTHERN MN EARLY THIS AFTN. IN ADDITION...THE MAIN SHRTWV
AND UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE JET CORE MOVING
ACROSS COLORADO...IS NOT EXPECTED TO MOVE ACROSS NE/IA/MN UNTIL
LATER THIS EVENING. A STRONGER STORM NORTH OF KOMA AS OF 19Z IS A
REFLECTION OF A STRENGTHENING LLJ AHEAD OF THIS JET ENERGY MOVING
OUT OF COLORADO.
SHORT TERM MESOSCALE CONVECTIVE PARAMETERS /HRRR/RUC/ HAVE
DEPICTED THAT THE SHRA/TSRA ACROSS SOUTHERN MN SHOULD BE MOVING
ACROSS EASTERN MN/WESTERN WI BY 00Z...WITH MOST OF THE
STRONGER/SVR ACTIVITY FORMING SOUTH ACROSS IOWA. IN
ADDITION...THESE SAME MESOSCALE CONVECTIVE PARAMETERS HAVE ANOTHER
LINE OF SHRA/TSRA FORMING WEST OF THE TWIN CITIES ARND 2-4Z ALONG
AND AHEAD OF THE APPROACHING SFC FRONT. THIS MAY BE THE MAIN
PLAYER TONIGHT...AS SAID BEFORE...THE AFTN CAP WILL LIKELY HOLD
FOR A FEW MORE HRS...SETTING THE STAGE FOR AN EVENING EVENT.
OTHERWISE...SHRA/TSRA SHOULD CONTINUE TO FORM ALONG AND AHEAD OF
THIS SFC FRONT LATER THIS EVENING AND MOVE EASTWARD DURING THE
OVERNIGHT HRS. BY MORNING...MOST OF THE ACTIVITY SHOULD BE EAST OF
MPX FA...WITH ONLY RESIDUAL SHRA IN WC WI.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 252 PM CDT SUN AUG 31 2014
TUESDAY-WEDNESDAY...THE FIRST COUPLE DAYS OF THE EXTENDED PORTION
WILL BE DOMINATED BY GENERALLY ZONAL FLOW ALOFT WHILE SFC HIGH
PRES OVER THE CENTRAL PLAINS SHIFTS E INTO THE OHIO VALLEY. THIS
WILL SPELL A WEAK PRES PATTERN OVER THE UPR MISS RIVER VALLEY
REGION WITH WEAK SUPPORT ALOFT. HOWEVER...THE RELATIVELY WEAK
INFLUENCE OF HIGH PRESSURE AS IT STAYS S OF THE REGION MEANS THAT
THERE WILL BE FAIRLY INEFFECTIVE CAPPING WITHIN A CONTINUED DEEPLY
MOIST ENVIRONMENT. WEAK BUCKLES IN THE ZONAL FLOW CAN EASILY SPARK
ISOLD SHOWERS AND POSSIBLY EVEN A HANDFUL OF TSTMS ACRS THE REGION
DURING THIS PERIOD SO SPOTTY SLGT CHC POPS ARE MAINTAINED IN THE
FCST. MUCH OF THE FCST AREA WILL REMAIN DRY...BUT ANY LOCATIONS
THAT DO SEE SOME PRECIP WILL NOT RECEIVE MUCH IN THE WAY OF QPF.
OTHERWISE...TEMPS AND DEWPOINTS WILL GO ON A SLIGHT INCREASING
TREND AS WINDS SHIFT FROM WLY TO SLY ON THE BACKSIDE OF THE
DEPARTING HIGH PRES AREA.
WEDNESDAY NIGHT-THURSDAY NIGHT...A LARGE LONGWAVE TROUGH DROPPING
OUT OF THE GULF OF ALASKA MON WILL MOVE ONSHORE THE PAC NW
REGION TUE EVE AND SLOWLY MAKE ITS WAY INTO THE CENTRAL CONUS
DURING THE MIDDLE PORTION OF THE WEEK. THIS TROUGH WILL PICK UP A
DEVELOPING LOW PRES CENTER OVER MT...SHIFTING IT INTO THE DAKOTAS
AND EVENTUALLY NRN MN BY MIDDAY THU. THE COMBINATION OF THE
DIGGING TROUGH AND THIS LOW PRES CENTER DEEPENING OVER THE ERN
DAKOTAS AND MN WILL CREATE ADDITIONAL POTENTIAL FOR SCATTERED
SHOWERS AND THUNDERSTORMS FOR MUCH OF THE AREA LATE WED THRU THU
NIGHT. THE FRONT LOOKS TO STALL OUT OVER CENTRAL MN THU...SO THIS
MAY ALTER THE DURATION OF HAVING POPS IN THE FCST OVER THE NEXT
FEW DAYS WORTH OF MODEL RUNS.
FRIDAY-SUNDAY...THOUGH THE SFC REFLECTION OF THE LOW PRES SYSTEM
LOOKS TO BE E OF THE WFO MPX CWFA BY DAYBREAK FRI MRNG...THE
ASSOCIATED TROUGH AXIS ALOFT WILL BE DRAGGING ITS WAY THROUGH THE
REGION DURG THE DAY ON FRI. THIS MAY LEAD TO SOME SHOWERS WITH THE
RELATIVE CORE OF THE SYSTEM STILL PASSING THRU. BEHIND THESE
DISTURBANCES AT THE SFC AND ALOFT...MORE PRONOUNCED NW FLOW ALOFT
WILL DOMINATE THRU THE WEEKEND WHILE HIGH PRES SLOWLY SHIFTS SE.
THIS COMBINATION WILL ALLOW FOR A DRYING OUT PERIOD FOR NEXT
WEEKEND ALONG WITH COOLER AND LESS HUMID CONDITIONS. HIGHS WILL
DROP BACK TO THE UPR 60S AND LWR 70S BY NEXT WEEKEND WITH LOWS
FALLING INTO THE UPR 40S AND LWR 50S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1219 AM CDT MON SEP 1 2014
THUNDER THREAT LARGELY DONE ACROSS THE MPX AIRSPACE...BUT STRONG
UPPER WAVE BACK BY SIOUX FALLS STILL HAS TO WORK ACROSS SRN MN/WRN
WI TONIGHT...WHICH WILL KEEP SCT SHOWERS GOING THROUGH MUCH OF THE
NIGHT...AS WE ARE SEEING WITH THE HRRR. BIGGER QUESTION MARK
REVOLVES AROUND STRATUS/FOG POTENTIAL TONIGHT. CERTAINLY THIS
STRATIFORM RAIN WE ARE SEE OUT THERE NOW WILL HELP MOISTEN THE
ATMO AND INCREASE THE THREAT FOR STRATUS...BUT CIGS AT THE START
ARE LARGELY UP AROUND 10K FT...SO WE HAVE A WAYS TO GO. FOLLOWED
THE IDEA OF THE RAP THOUGH WITH STATUS EVENTUALLY FILLING IN
WITHIN AND EAST OF THE WEAKENING SFC TROUGH...WHICH AT 6Z
STRETCHED FROM ABOUT NEW ULM TO MILLE LACS LAKE. THIS MOISTURE
LOOKS TO GET SCOURED OUT PRETTY QUICK BY WNW WINDS IN THE
MORNING...WITH MOST OF LABOR DAY GOING BY WITH VFR CONDS. DURING
THE LATE AFTERNOON...ANOTHER UPPER WAVE WILL BE COMING OUT OF THE
DAKOTAS...BUT IT LOOKS TO DO NOTHING MORE THAN PROVIDE US WITH AN
INCREASE IN MID CLOUDS AND PERHAPS A FEW SPRINKLES AS WE HEAD INTO
MONDAY NIGHT.
KMSP...STRATIFORM RAIN WE ARE SEEING NOW FAVORED ME TOWARD KEEPING
THE DEVELOPMENT OF SUB 018 CIGS WE HAD IN THE TAF...BUT WITH CIGS
STILL ABOVE 5K FT...NOT COMPLETELY SOLD ON THOSE RESTRICTIONS
HAPPENING. OTHER THAN THAT...NO OTHER CONCERNS ARE EXPECTED THIS
PERIOD.
/OUTLOOK FOR KMSP/
TUE...VFR. WINDS WSW 5-10 KTS.
WED...VFR. CHC MVFR/TSRA LATE. WINDS S 5-10 KTS.
THU...VFR. CHC MVFR/TSRA. WINDS S BCMG W 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JLT
LONG TERM...JPC
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1151 PM CDT Sun Aug 31 2014
.SHORT TERM...(This Evening through Wednesday Afternoon)
Issued at 357 PM CDT SUN AUG 31 2014
Afternoon water vapor imagery showing long advertised Pacific trough
digging into the central Plains this afternoon...with strong
shortwave energy now seen entering western Nebraska. Strengthening
wind fields along the southern edge of this feature have advected
Mexican Plateau air /i.e. elevated mixed layer/ east across the
central/southern Plains as seen on the latest 7.4 micron water vapor
GOES sounder channel. Latest RUC analysis shows 7-500 mb lapse rates
approaching 9C/km across western Kansas and Nebraska...and fcst
models suggest this mid-level airmass will continue tracking east
into our region overnight. Along the surface...latest analysis shows
a developing leeside low across southeastern Colorado...with a
northward extending frontal boundary draped across the Plains which
then joins the main area of low pressure now found along the
Minnesota/Manitoba border. With time this evening...aforementioned
boundary will progress eastward as upstream troughing continues to
settle into the central and southern Plains. Airmass ahead of both
the cold front and upper wave continues to destabilize with latest
SPC meso graphics yielding as much as 3500 joules of MLCAPE between
KC and Topeka. Most importantly however...deep layered shear will
continue increasing as well as mid- level wind max moves into the
area overnight. All said...ingredients appear to be coming together
for a fairly active evening and overnight period.
Latest radar trends now showing developing cells across north-central
Kansas along the previously mentioned frontal boundary. Storms
should continue to fire this afternoon before gradually spreading east
through the early evening and overnight. As has been advertised in
recent days quite well by numerical models...isolated convection to
our west and north will likely congeal into a forward propagating MCS
this evening just before it enters northwestern Missouri. As this
occurs...deep layered shear will continue to strengthen as a low-
level jet increases to nearly 50 kts directly overhead. This poses
two potential issues for our region:
1) Maintenance of ongoing severe weather as cold pool continues to
track southeast with time into northwest Missouri/northeast Kansas
2) Increasing likelihood for developing heavy rain/possible flooding as
low-level jet ascends any convectively generated cold pools
The above said...main concerns severe-wise for our area will remain
strong damaging winds as cold pool for developing MCS tracks south
and east with time. Current thinking is damaging wind potential will
gradually decrease as storms approach the greater KC area...however
cannot rule out strong gusts in and around the metro during the late
evening hrs. Additionally...a low-end tornado threat does exist across
far northwest Missouri as strong updrafts continue to tilt horizontal
vorticity into the vertical along the leading edge of the cold pool
as it tracks south and east with time. For now...agree completely with
where SPC has the highest tornado threat /NW MO/ as further progress
to the south and east will likely result in a less favorable
environment due to nocturnal cooling/low-level stabilization effects.
In terms of hydro concerns...have elected to go with a flash flood
watch for much of northwest MO/northeast Kansas as potential exists
for training convection if an outflow boundary lays out across
central Missouri. As alluded to above...strength of developing low-
level jet is a little concerning especially when PWAT values are
expected to increase to anywhere between 2-3 standard deviations
above normal as main front approaches. HPC QPF shows a 2+ inch
bullseye directly west of KC which appears to be in favor of
developing training after midnight. Would rather play it safe hence
the current flash flood watch which runs from 2z this evening through
15z Monday morning.
Front to slowly settle south of the region during the early morning
hrs. Another round of strong to severe storms is possible on
Monday...primarly south of the the greater KC area as daytime
heating combines with still impressive wind fields aloft. For
tomorrow...more optimal timing may support isolated supercell
structures as opposed to tonight/s linear activity. Regardless...have
maintained likely pops for most areas south of I-70 during the
afternoon hrs.
Front to clear the area tomorrow night which should support a mostly
dry Tuesday. Front slowly expected to lift north as a warm front
through the day on Wednesday but minimal impacts expected as no
significant features are at play to enhance upward vertical motion.
Temps by then should begin to rise with low to mid 90s possible
Wednesday afternoon as southerly flow reinvades the area.
.LONG TERM...(Wednesday Evening through Sunday)
Issued at 357 PM CDT SUN AUG 31 2014
A little bit of everything during the extended portion of the
forecast. Storms early Wednesday, followed by a return of hot and
humid air until a cold front and more storms on Friday, then finally
some fall-like weather over the weekend.
Medium range models all on the same page with the overall pattern.
Mid-week zonal flow backs to the southwest in response to an upper
trough tracking east from the Northern Rockies through the Upper MS
Valley by Friday.
Elevated convection associated with a northward returning warm front
will affect the CWA early Wednesday followed by hot and humid air
spreading back into the region. This will likely last into Friday
when the southern extension of the Northern Plains upper trough
forces a cold front south and through the Mid MO River Valley by
Saturday morning. Moderately strong and broad area of high pressure
expanding southward will bring some much needed relief from the high
humidities.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 1151 PM CDT SUN AUG 31 2014
Line of storms that affected the terminals tonight has moved through as
of this time, leaving strati-form rain and VCTS as the primary weather
at our sites currently. This activity could last through 11Z at the
Kansas City terminals, but should end sooner at KSTJ --09Z--.
Otherwise, expect southerly winds to prevail for much of the day
behind the exiting rain. There will be a returning threat for
thunderstorms generally near and south of Kansas City again Monday
afternoon, so have inserted VCTS in after 21Z.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH until 10 AM CDT Monday FOR KSZ025-102>105.
MO...FLASH FLOOD WATCH until 10 AM CDT Monday FOR MOZ001>005-011>014-
020>022-028>030-037.
&&
$$
SHORT TERM...32
LONG TERM...MJ
AVIATION...Cutter
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1123 PM CDT Sun Aug 31 2014
.UPDATE:
Issued at 905 PM CDT Sun Aug 31 2014
Progressive UA trof and associated cold front, as well as outflow
boundaries produced by intense convection so far this evening,
should cause convection stretching from western Iowa to central KS to
push across the NW half of our FA overnight. Rough timing based
on extrapolation of upstream radar data suggests leading edge of
precip moving into the Edina area by 05z/midnight. While we are
missing much of today`s explicit guidance, from the data that is
available believe that the latest HRRR output has a best handle on
overnight trends in two aspects...being faster with the eastward
progression and suggesting that some precip may be knocking on the
western door of the STL metro by daybreak, and secondly more of a
focus on late night/predawn convection over eastern KS/W MO where
there should be good cold pool/low level jet interaction which
should focus the most robust convection in this area.
Forecast inherited from dayshift already trended specifics towards
the trends mentioned above, so going forecast looks quite good and
only minor adjustments needed to speed up onset of higher PoPs by
1-2 hours. If HRRR scenario does pan out I`m not too certain
about how much of a severe weather threat will reach our area, but
as mentioned by day shift there will likely be at least some
impact from upstream outflows that propagate east and produce
gusty winds.
Specific trends for Labor Day and Monday night...including the
potential for severe weather and heavy rain...will largely hinge on
how convection evolves across the region during the predawn hours
and into Monday morning; specifically how long the early morning
convection lingers and where the associated outflow boundary will be
located during the afternoon. While there is still quite a bit of
uncertainty on how the convection will evolve, it certainly appears
that outdoor plans may be altered in many areas due to the
weather.
Update will be issued as soon as 02x surface data can be ingested
and assimilated into database.
Truett
&&
.SHORT TERM: (Through Late Tonight)
Issued at 350 PM CDT Sun Aug 31 2014
Isolated to widely scattered thunderstorms over southeast portions
of the CWFA should dissipate fairly quickly this evening. Until
then, locally heavy downpours will continue over parts of the
eastern Ozarks. Attention turns to tonight as a strong shortwave
will move from eastern Wyoming into the eastern Nebraska/northwest
Missouri. An MCS is expected to develop ahead of it on the nose of
a 40kt low level jet over the eastern Plains. The model consensus
keeps the vast majority of the precipitation over western/north
central Missouri tonight. However, it does look like the leading
edge will nose into central and northeast Missouri between 08Z and
12Z. Not sure how much of the strength of the storms by that
point. Current thinking is that the cold pool may outrun the best
forcing causing the MCS to weaken as it moves east. This scenario
would have the rain moving into western portions of the CWFA between
08Z and 10Z. There may be some gusty winds as the outflow moves
through, but the most significant impact would likely be locally
heavy rain; and that looks more likely over western Missouri than in
central Missouri.
Carney
.LONG TERM: (Monday through Next Sunday)
Issued at 350 PM CDT Sun Aug 31 2014
We will see a break in what has been a hot pattern for us this past
week, as the upper level ridge breaks down, thanks to a pair of
decently strong shortwave TROFs. Much of the energy from these
shortwaves will pass us to the north, but nevertheless, we are
expecting high probabilities of rain from both of these systems
because of either a favorable position of the low level jet or
synoptic front and a very moist, deep warm-cloud atmosphere.
The first system is expected to be ongoing early Monday morning for
areas north and west of STL metro while in a slowly weakening
state. This rain is expected to reach the STL metro area before
dissipating or scattering out, with an anticipated boundary setup
near or just south of the I-70 corridor for new development in the
afternoon. There is also some potential for scattered development
Monday afternoon further north and west near the synoptic front in
northern MO and central IL.
The second system on Monday night should make more of a pass to the
south and interact with the synoptic front now deeper into our
region and favorable axis of the low level jet. In addition, there
is potential for localized heavy rainfall with PWs of around 2
inches and warm-cloud depths in excess of 4km and training storms.
The front is then expected to stall over southern MO Tuesday before
pushing north as a warm front on Wednesday with persistent, but
lesser, chances for storms.
While the humidity air never really goes away thru late week, it
should be just cool enough to prevent any dangerous heat and
humidity conditions until perhaps when the warm front pushes thru
Wednesday and into Friday.
A period of dry weather is anticipated Thursday through early Friday
with a warm-sector setup, with the next, and what looks to be much
stronger, cold front pushing thru late Friday thru early Saturday.
Increased chances for rain will return with the front with all early
indications showing a cool and dry period next weekend for most
areas.
TES
&&
.AVIATION: (For the 06z TAFs through 06z Monday Night)
Issued at 1103 PM CDT Sun Aug 31 2014
Convection extending from IA southwest through northwestern MO and
KS just ahead of a cold front will drop southeastward into the
UIN and COU areas late tonight, and then eventually into the St
Louis metro area towards morning as it weakens. New convective
development is expected late Monday afternoon and early evening
mainly in COU and the St Louis metro area between the approaching
cold front and an outflow boundary left from the late
night/morning storm complex. S-sely surface winds late tonight
will gradually veer around to a swly direction Monday morning.
Specifics for KSTL: Weakening showers and storms are expected to
drop southeastward into STL area by early Monday morning. There
will be a break in the convection with redevelopment of storms
expected late Monday afternoon and evening. S-sely surface winds
late tonight wlll increase to around 14 kts by late Monday
morning from a swly direction.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1050 PM EDT TUE SEP 2 2014
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL PUSH ACROSS THE NORTH COUNTRY
THROUGH THE EVENING HOURS AHEAD OF A COLD FRONT. EXPECT LOCALLY
HEAVY DOWNPOURS AND GUSTY WINDS WITH THE STRONGER STORMS. SUNNY,
DRY AND COOLER WEATHER WILL LAST INTO THURSDAY. WARM SUMMER WEATHER
RETURNS FRIDAY BUT WILL BE SHORT LIVED AS ANOTHER COLD FRONT SWEEPS IN
EARLY SATURDAY GIVING A TASTE OF FALL-LIKE WEATHER FOR SUNDAY AND
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/...
AS OF 1044 PM EDT TUESDAY...COLD FRONT CONTINUES TO MAKE ITS WAY
EASTWARD ACROSS VERMONT LATE THIS EVENING...AND WILL EXIT THE
FORECAST AREA BETWEEN 05Z-06Z. HEAVIEST PRECIPITATION WITH SOME
EMBEDDED THUNDER ALONG THE COLD FRONT...WITH POST FRONTAL RAINS
ACROSS REST OF VERMONT AND NORTHEAST NEW YORK ASSOCIATED WITH
TRAILING MID LEVEL SHORTWAVE. MAIN THREAT THIS EVENING HAS BEEN HEAVY
RAINFALL. HOWEVER...RAINFALL RATES IN HEAVIER PRECIPITATION HAVE
DECREASED ENOUGH SO THAT THREAT OF FLASH FLOODING HAS DIMINISHED.
HAVE MADE SOME MINOR ADJUSTMENTS TO FORECAST WITH LATEST UPDATE TO
ACCOUNT FOR LATEST OBSERVATIONAL DATA AND TRENDS.
EARLIER DISCUSSION...
WELL, THE ATMOSPHERE IS FAIRLY PRIMED. VERY WARM AND HUMID
AIRMASS IS RESULTING IN MODEST SURFACE BASED INSTABILITY (CAPE
PUSHING 2000 J/KG AND LIFTED INDEX OF -2 TO -4C). SO FAR THE
ACTIVITY HAS BEEN SPARSE ACROSS THE FORECAST AREA, HOWEVER RADAR
SHOWS THE BUILDING LINE OF SHOWERS AND THUNDERSTORMS OUT ACROSS
ONTARIO. THESE STORMS SHOULD BE CROSSING INTO THE UNITED STATES IN
THE NEXT COUPLE OF HOURS. STILL LIKE HOW THE HRRR AND OUR LOCAL
6KM WRF ARE HANDLING THE EVOLUTION OF THE CONVECTION. STILL LOOKS
LIKE AN ETA INTO THE CHAMPLAIN VALLEY DURING THE EVENING (LET`S GO
WITH 6-8PM) AND THEN INTO EASTERN VERMONT BY 10PM. UPPER LEVEL
SHORTWAVE WHICH IS THE PRIMARY TRIGGER FOR THE CONVECTION IS NOW
OVER MICHIGAN AND STARTING TO LIFT NORTHEAST. OUT AHEAD OF THAT
SHORT WAVE THE WIND FIELDS AND RELATED SHEAR INCREASE, BUT AT THE
SAME TIME WE ARE GETTING CLOSER TO SUNSET AND LOSS OF HEATING. SO
IT`S A BATTLE BETWEEN TIMING OF THE BEST DYNAMICS VS BEST
INSTABILITY.
AT THIS POINT STILL SEE NOTHING TO CHANGE THE IDEA THAT WE`LL HAVE
AT LEAST A FEW STRONG T-STORMS AROUND, ESPECIALLY THIS EVENING AND
MAINLY WEST OF THE GREEN MOUNTAINS. HAVE MAINTAINED THE IDEA OF
GUSTY WINDS AND HEAVY RAIN AS THE PRIMARY THREATS.
THE ACTIVITY WINDS DOWN BY MID EVENING IN THE ST LAWRENCE VALLEY
TO JUST AFTER MIDNIGHT IN EASTERN VERMONT. DEPENDING ON HOW MUCH
CLEARING WE GET, WE COULD HAVE A BIT OF PATCHY FOG LATE TONIGHT.
THE COOLER AIR LAGS THE WEATHER A BIT, SO IT WILL STILL BE A MUGGY
NIGHT WITH LOWS IN THE 60S.
&&
.SHORT TERM /8 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 355 PM EDT TUESDAY...IT WILL BE A QUIET 48 HOURS. SHORT TERM
MODELS IN PRETTY GOOD AGREEMENT WITH REGARD TO RIDGING OVER THE REGION.
DAILY SPECIFICS...
WEDNESDAY: FLOW TURNS NORTHWEST DURING THE MORNING. 850MB
TEMPERATURES FALL TO 11-12C WHICH WILL SUPPORT HIGH TEMPERATURES
IN THE MID-UPPER 70S. WITH SOME WEAK COLD-AIR ADVECTION AND A GOOD
DEAL OF SUN, WE`LL HAVE SOME EXCELLENT MIXING DURING THE
AFTERNOON. WE SHOULD BE ABLE TO TAP SOME OF THE 20KT OR SO OF WIND
THAT WILL BE A FEW THOUSAND FEET UP, SO IT SHOULD GET A LITTLE
BREEZY IN THE AFTERNOON.
WEDNESDAY NIGHT: HIGH PRESSURE OVERHEAD. CLEAR AND CALM, SO PATCHY
FOG LOOKS LIKE A GOOD BET, ESPECIALLY SINCE THE GROUND WILL STILL
BE A BIT DAMP FROM THE RAIN THIS EVENING. TEMPERATURES MAINLY IN
THE 50S, THOUGH UPPER 40S POSSIBLE IN COLD SPOTS LIKE SARANAC LAKE.
THURSDAY: SHORTWAVE RIDGING AND SURFACE HIGH PRESSURE STILL NEARLY
OVERHEAD, BUT STARTING TO PUSH EAST OF THE AREA. 850MB
TEMPERATURES UP TO 12-13C, WHICH SUPPORTS UPPER 70S TO LOW 80S FOR
HIGHS. PLENTY OF SUN AS WELL.
THURSDAY NIGHT: DISCARDED THE NAM AS IT SEEMS TOO AGRESSIVE WITH
THE LEADING EDGE OF WARM AIR ADVECTION AND PRODUCES THICKENING
CLOUDS AND EVEN SOME LIGHT SHOWERS. THINK IT WILL REMAIN MOSTLY
CLEAR AND DRY PER OTHER MODELS. HOWEVER WITH SOUTHWEST FLOW
DEVELOPING, IT WON`T BE AS COLD, LOTS OF 50S AND EVEN LOW 60S FOR
LOWS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 350 PM EDT TUESDAY...EXTENDED PERIOD REMAINS PREDOMINATELY
QUIET...LARGELY DOMINATED BY HIGH PRESSURE STARTING THE LATTER
PART OF THE WEEKEND...BUT WET TO BEGIN. FOR THE START OF THE
PERIOD...RISING HEIGHTS AND WARMING TEMPERATURES CONTINUE FRIDAY
AS AN UPPER RIDGE CRESTS OVER THE NORTHEAST IN ADVANCE OF OUR NEXT
SURFACE FRONT. MEAN 925MB TEMPS OF +20-23C WILL SUPPORT HIGHS WELL
ABOVE NORMAL FOR EARLY SEPTEMBER WITH WIDESPREAD 80`S EXPECTED.
IT`LL BE MUGGY TOO WITH DEWPOINTS RANGING THROUGH THE 60S WHICH
WILL CREATE AMPLE SURFACE INSTABILITY TO SUPPORT SHOWER AND
THUNDERSTORM DEVELOPMENT ALONG/AHEAD OF THE AFOREMENTIONED FRONT
WHICH WILL SHIFT INTO THE BTV CWA LATE IN THE DAY AND THROUGH THE
EVENING. STILL LOOKS LIKE THE BEST UPPER DYNAMICS PASSES TO OUR
NORTH...WITH THE SURFACE BOUNDARY PARALLEL WITH UPPER FLOW
SUPPORTING THE IDEA OF A SLOW EASTWARD PROGRESSION WHICH IS
MAINTAINED BY THE LATEST ECMWF. GFS REMAINS A BIT FASTER PUSHING
THE BOUNDARY THROUGH THE CWA BY SATURDAY MORNING SO HAVE CONTINUED
ON WITH THE PREVIOUS FORECAST THINKING LEANING TOWARDS THE ECMWF.
BY LATE SATURDAY TREND WILL BE TOWARDS CLEARER AND DRIER WEATHER AS
THE UPPER FLOW TURNS ZONAL AND SURFACE HIGH PRESSURE BUILDS
EASTWARD OUT OF THE CENTRAL CONUS. THIS HIGH THEN SLOWLY SHIFTS EAST
THROUGH THE NORTHEAST AND OFF INTO THE CANADIAN MARITIMES BY LATE
TUESDAY OFFERING A NICE STRETCH OF LATE SUMMER WEATHER. TEMPS RETURN
TO MORE SEASONABLE LEVELS TO MAYBE SLIGHTLY BELOW NORMAL WITH
EXPECTED HIGHS SATURDAY THROUGH TUESDAY IN THE UPPER 60S TO LOW
70S...AND LOWS IN THE MID 40S TO LOW 50S.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 00Z THURSDAY...VARIABLE FLIGHT CONDITIONS ACROSS THE
FORECAST AREA THIS EVENING AS SHOWERS AND THUNDERSTORMS
ALONG/AHEAD OF A COLD FRONT ADVANCE EASTWARD ACROSS FORECAST AREA
THROUGH MIDNIGHT. CIGS WILL PRIMARILY REMAIN VFR BUT VSBY WILL BE
REDUCED TO MVFR/IFR IN HEAVIER SHOWERS AND EMBEDDED STORMS. AFTER
06Z...PRECIP IS EAST OF THE REGION LEAVING GENERALLY CLOUDY SKIES.
CIGS OVERNIGHT WILL GENERALLY BE VFR AT KMSS/KPBG/KBTV...BUT MVFR
AT KRUT/KSLK/KMPV WITH POSSIBLE IFR AT KRUT UNDER BLOCKED FLOW.
SOME PATCHY FOG ALSO POSSIBLE...ESPECIALLY AT KSLK/KMPV.
AFTER 12Z...ALL CIGS LIFT TO VFR WITH SCT-BKN DIURNAL
STRATOCUMULUS EXPECTED THROUGH THE DAY.
OUTLOOK 00Z THURSDAY THROUGH SUNDAY...
00Z THU - 00Z SAT...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR
FOG POSSIBLE...ESPECIALLY AT KMPV/KSLK.
00Z SAT - 00Z SUN...POSSIBLE MVFR AND BRIEF IFR IN SCATTERED SHOWERS
AND THUNDERSTORMS.
00Z SUN - 00Z MON...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR FOG
POSSIBLE...ESPECIALLY AT KMPV/KSLK.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...NASH
NEAR TERM...RJS/NASH
SHORT TERM...NASH
LONG TERM...LAHIFF
AVIATION...RJS/LAHIFF
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
812 PM EDT TUE SEP 2 2014
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL PUSH ACROSS THE NORTH COUNTRY
THROUGH THE EVENING HOURS AHEAD OF A COLD FRONT. EXPECT LOCALLY
HEAVY DOWNPOURS AND GUSTY WINDS WITH THE STRONGER STORMS. SUNNY,
DRY AND COOLER WEATHER WILL LAST INTO THURSDAY. WARM SUMMER WEATHER
RETURNS FRIDAY BUT WILL BE SHORT LIVED AS ANOTHER COLD FRONT SWEEPS IN
EARLY SATURDAY GIVING A TASTE OF FALL-LIKE WEATHER FOR SUNDAY AND
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/...
AS OF 755 PM EDT TUESDAY...COLD FRONT MOVING THROUGH NORTHERN
PORTION OF CHAMPLAIN VALLEY AT THIS TIME...WILL CONTINUE TO MAKE
ITS WAY EAST THIS EVENING AND EXIT THE FORECAST AREA BETWEEN 04Z-
06Z. HEAVIEST PRECIPITATION WITH SOME EMBEDDED THUNDER ALONG THE
COLD FRONT...WITH POST FRONTAL RAINS ACROSS NORTHERN NEW YORK
ASSOCIATED WITH TRAILING MID LEVEL SHORTWAVE. MAIN THREAT THIS
EVENING WILL BE HEAVY RAINFALL AND THREAT OF FLASH
FLOODING...MAINLY FROM CHAMPLAIN VALLEY EASTWARD. ONLY MINOR
ADJUSTMENTS MADE TO FORECAST WITH LATEST UPDATE.
PREVIOUS DISCUSSION... WELL, THE ATMOSPHERE IS FAIRLY PRIMED. VERY
WARM AND HUMID AIRMASS IS RESULTING IN MODEST SURFACE BASED
INSTABILITY (CAPE PUSHING 2000 J/KG AND LIFTED INDEX OF -2 TO
-4C). SO FAR THE ACTIVITY HAS BEEN SPARSE ACROSS THE FORECAST
AREA, HOWEVER RADAR SHOWS THE BUILDING LINE OF SHOWERS AND
THUNDERSTORMS OUT ACROSS ONTARIO. THESE STORMS SHOULD BE CROSSING
INTO THE UNITED STATES IN THE NEXT COUPLE OF HOURS. STILL LIKE HOW
THE HRRR AND OUR LOCAL 6KM WRF ARE HANDLING THE EVOLUTION OF THE
CONVECTION. STILL LOOKS LIKE AN ETA INTO THE CHAMPLAIN VALLEY
DURING THE EVENING (LET`S GO WITH 6-8PM) AND THEN INTO EASTERN
VERMONT BY 10PM. UPPER LEVEL SHORTWAVE WHICH IS THE PRIMARY
TRIGGER FOR THE CONVECTION IS NOW OVER MICHIGAN AND STARTING TO
LIFT NORTHEAST. OUT AHEAD OF THAT SHORT WAVE THE WIND FIELDS AND
RELATED SHEAR INCREASE, BUT AT THE SAME TIME WE ARE GETTING CLOSER
TO SUNSET AND LOSS OF HEATING. SO IT`S A BATTLE BETWEEN TIMING OF
THE BEST DYNAMICS VS BEST INSTABILITY.
AT THIS POINT STILL SEE NOTHING TO CHANGE THE IDEA THAT WE`LL HAVE
AT LEAST A FEW STRONG T-STORMS AROUND, ESPECIALLY THIS EVENING AND
MAINLY WEST OF THE GREEN MOUNTAINS. HAVE MAINTAINED THE IDEA OF
GUSTY WINDS AND HEAVY RAIN AS THE PRIMARY THREATS.
THE ACTIVITY WINDS DOWN BY MID EVENING IN THE ST LAWRENCE VALLEY
TO JUST AFTER MIDNIGHT IN EASTERN VERMONT. DEPENDING ON HOW MUCH
CLEARING WE GET, WE COULD HAVE A BIT OF PATCHY FOG LATE TONIGHT.
THE COOLER AIR LAGS THE WEATHER A BIT, SO IT WILL STILL BE A MUGGY
NIGHT WITH LOWS IN THE 60S.
&&
.SHORT TERM /8 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 355 PM EDT TUESDAY...IT WILL BE A QUIET 48 HOURS. SHORT TERM
MODELS IN PRETTY GOOD AGREEMENT WITH REGARD TO RIDGING OVER THE REGION.
DAILY SPECIFICS...
WEDNESDAY: FLOW TURNS NORTHWEST DURING THE MORNING. 850MB
TEMPERATURES FALL TO 11-12C WHICH WILL SUPPORT HIGH TEMPERATURES
IN THE MID-UPPER 70S. WITH SOME WEAK COLD-AIR ADVECTION AND A GOOD
DEAL OF SUN, WE`LL HAVE SOME EXCELLENT MIXING DURING THE
AFTERNOON. WE SHOULD BE ABLE TO TAP SOME OF THE 20KT OR SO OF WIND
THAT WILL BE A FEW THOUSAND FEET UP, SO IT SHOULD GET A LITTLE
BREEZY IN THE AFTERNOON.
WEDNESDAY NIGHT: HIGH PRESSURE OVERHEAD. CLEAR AND CALM, SO PATCHY
FOG LOOKS LIKE A GOOD BET, ESPECIALLY SINCE THE GROUND WILL STILL
BE A BIT DAMP FROM THE RAIN THIS EVENING. TEMPERATURES MAINLY IN
THE 50S, THOUGH UPPER 40S POSSIBLE IN COLD SPOTS LIKE SARANAC LAKE.
THURSDAY: SHORTWAVE RIDGING AND SURFACE HIGH PRESSURE STILL NEARLY
OVERHEAD, BUT STARTING TO PUSH EAST OF THE AREA. 850MB
TEMPERATURES UP TO 12-13C, WHICH SUPPORTS UPPER 70S TO LOW 80S FOR
HIGHS. PLENTY OF SUN AS WELL.
THURSDAY NIGHT: DISCARDED THE NAM AS IT SEEMS TOO AGRESSIVE WITH
THE LEADING EDGE OF WARM AIR ADVECTION AND PRODUCES THICKENING
CLOUDS AND EVEN SOME LIGHT SHOWERS. THINK IT WILL REMAIN MOSTLY
CLEAR AND DRY PER OTHER MODELS. HOWEVER WITH SOUTHWEST FLOW
DEVELOPING, IT WON`T BE AS COLD, LOTS OF 50S AND EVEN LOW 60S FOR
LOWS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 350 PM EDT TUESDAY...EXTENDED PERIOD REMAINS PREDOMINATELY
QUIET...LARGELY DOMINATED BY HIGH PRESSURE STARTING THE LATTER
PART OF THE WEEKEND...BUT WET TO BEGIN. FOR THE START OF THE
PERIOD...RISING HEIGHTS AND WARMING TEMPERATURES CONTINUE FRIDAY
AS AN UPPER RIDGE CRESTS OVER THE NORTHEAST IN ADVANCE OF OUR NEXT
SURFACE FRONT. MEAN 925MB TEMPS OF +20-23C WILL SUPPORT HIGHS WELL
ABOVE NORMAL FOR EARLY SEPTEMBER WITH WIDESPREAD 80`S EXPECTED.
IT`LL BE MUGGY TOO WITH DEWPOINTS RANGING THROUGH THE 60S WHICH
WILL CREATE AMPLE SURFACE INSTABILITY TO SUPPORT SHOWER AND
THUNDERSTORM DEVELOPMENT ALONG/AHEAD OF THE AFOREMENTIONED FRONT
WHICH WILL SHIFT INTO THE BTV CWA LATE IN THE DAY AND THROUGH THE
EVENING. STILL LOOKS LIKE THE BEST UPPER DYNAMICS PASSES TO OUR
NORTH...WITH THE SURFACE BOUNDARY PARALLEL WITH UPPER FLOW
SUPPORTING THE IDEA OF A SLOW EASTWARD PROGRESSION WHICH IS
MAINTAINED BY THE LATEST ECMWF. GFS REMAINS A BIT FASTER PUSHING
THE BOUNDARY THROUGH THE CWA BY SATURDAY MORNING SO HAVE CONTINUED
ON WITH THE PREVIOUS FORECAST THINKING LEANING TOWARDS THE ECMWF.
BY LATE SATURDAY TREND WILL BE TOWARDS CLEARER AND DRIER WEATHER AS
THE UPPER FLOW TURNS ZONAL AND SURFACE HIGH PRESSURE BUILDS
EASTWARD OUT OF THE CENTRAL CONUS. THIS HIGH THEN SLOWLY SHIFTS EAST
THROUGH THE NORTHEAST AND OFF INTO THE CANADIAN MARITIMES BY LATE
TUESDAY OFFERING A NICE STRETCH OF LATE SUMMER WEATHER. TEMPS RETURN
TO MORE SEASONABLE LEVELS TO MAYBE SLIGHTLY BELOW NORMAL WITH
EXPECTED HIGHS SATURDAY THROUGH TUESDAY IN THE UPPER 60S TO LOW
70S...AND LOWS IN THE MID 40S TO LOW 50S.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 00Z THURSDAY...VARIABLE FLIGHT CONDITIONS ACROSS THE
FORECAST AREA THIS EVENING AS SHOWERS AND THUNDERSTORMS
ALONG/AHEAD OF A COLD FRONT ADVANCE EASTWARD ACROSS FORECAST AREA
THROUGH MIDNIGHT. CIGS WILL PRIMARILY REMAIN VFR BUT VSBY WILL BE
REDUCED TO MVFR/IFR IN HEAVIER SHOWERS AND EMBEDDED STORMS. AFTER
06Z...PRECIP IS EAST OF THE REGION LEAVING GENERALLY CLOUDY SKIES.
CIGS OVERNIGHT WILL GENERALLY BE VFR AT KMSS/KPBG/KBTV...BUT MVFR
AT KRUT/KSLK/KMPV WITH POSSIBLE IFR AT KRUT UNDER BLOCKED FLOW.
SOME PATCHY FOG ALSO POSSIBLE...ESPECIALLY AT KSLK/KMPV.
AFTER 12Z...ALL CIGS LIFT TO VFR WITH SCT-BKN DIURNAL
STRATOCUMULUS EXPECTED THROUGH THE DAY.
OUTLOOK 00Z THURSDAY THROUGH SUNDAY...
00Z THU - 00Z SAT...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR
FOG POSSIBLE...ESPECIALLY AT KMPV/KSLK.
00Z SAT - 00Z SUN...POSSIBLE MVFR AND BRIEF IFR IN SCATTERED SHOWERS
AND THUNDERSTORMS.
00Z SUN - 00Z MON...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR FOG
POSSIBLE...ESPECIALLY AT KMPV/KSLK.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...NASH
NEAR TERM...RJS/NASH
SHORT TERM...NASH
LONG TERM...LAHIFF
AVIATION...RJS/LAHIFF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1033 PM EDT TUE SEP 2 2014
.SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS CENTRAL NC
ON WEDNESDAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR THE
REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM TUESDAY...
CONVECTION HAS LARGELY DISSIPATED ACROSS THE AREA THIS EVENING WITH
NOCTURNAL STABILIZATION TAKING HOLD. HOWEVER... AN APPROACHING LINE
OF SHOWERS AND STORMS... CURRENTLY MOVING EAST-SOUTHEASTWARD THROUGH
THE NC AND VA MOUNTAINS... IN ADVANCE OF A WEAK COLD FRONT IS
EXPECTED TO APPROACH/POSSIBLY MOVE INTO PORTIONS OF THE AREA
OVERNIGHT. WITH THE SPC MESOPAGE STILL SHOWING 1000-2000 J/KG OF
MUCAPE ACROSS OUR NORTHWEST/NORTHERN PIEDMONT AND THE LATEST RAP AND
HRRR SHOWING THE POTENTIAL FOR SOME OF THIS ACTIVITY TO MOVE INTO
THIS AREA (NW/N PIEDMONT) WILL LEAVE A CHANCE OF SHOWERS AND STORMS
IN THE FORECAST FOR THIS AREA. HOWEVER.. WITH THE LACK OF GOOD DEEP
SHEAR AND DAYTIME HEATING THINK THIS LINE WILL CONTINUE TO SHOW A
WEAKENING TREND AS IT MOVES INTO NW/N PORTIONS OF CENTRAL NC AROUND
MIDNIGHT OR SHORTLY AFTER. THUS... WOULD EXPECT ANY OF THIS
WEAKENING LINE TO REMAIN BELOW SEVERE LIMITS.
WHERE HEAVY RAINFALL OCCURRED THIS PAST AFTERNOON-EVENING (GENERALLY
ALONG AND SOUTH OF A LINE FROM ASHEBORO TO RALEIGH TO WILSON) AND
SKIES PARTIALLY CLEAR OVERNIGHT... WE COULD SEE PATCHES OF FOG
DEVELOP DURING THE PRE-DAWN HOURS OF WEDNESDAY. MIN TEMPS NEAR 70-
LOWER 70S.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 335 PM TUESDAY...
SHEAR AXIS AND ATTENDANT SURFACE BOUNDARY WILL LIE ACROSS THE
SOUTHERN COUNTIES OF CENTRAL NC. ISOLATED SHOWERS AND STORMS ALONG
THIS FEATURE WEDNESDAY MORNING WILL GROW IN COVERAGE AS THE
ATMOSPHERE HEATS UP...LEADING TO GREATER LOW LEVEL INSTABILITY.
RELATIVELY WEAK STEERING FLOW SUGGEST THAT THE STORMS WILL BE SLOW
MOVING. IF STORMS OCCUR OVER URBAN LOCATIONS...THIS MAY LEAD TO
MINOR FLOODING OF STREETS AND POOR DRAINAGE AREAS.
PLAN TO CAP POPS AT 50 PERCENT ACROSS THE SOUTH...DWINDLING TO 25-35
PERCENT ACROSS THE NW.
MAX TEMPS WEDNESDAY DEPENDENT ON WHEN CONVECTIVE COVERAGE INCREASES
AND WHETHER ANY PERIODS OF PARTIAL SUN OCCUR. BETTING ON SOME
PARTIAL SUN INT HE LATE MORNING-EARLY AFTERNOON PRIOR TO CONVECTION
INCREASING AFTER 2-3 PM. IF SKIES REMAIN OVERCAST OR CONVECTION
BECOMES ACTIVE BY LUNCHTIME...MAX TEMPS MAY END UP BEING 5-6 DEGREES
COOLER. CONTINUED WARM AND MUGGY WEDNESDAY NIGHT WITH SCATTERED
CONVECTION SLOWLY DIMINISHING/DISSIPATING. MIN TEMPS NEAR 70-LOWER
70S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 255 PM TUESDAY...
FOR THU/FRI: CONTINUED WARM/HUMID WITH DAILY SCATTERED SHOWERS AND
STORMS. AT THE SURFACE... THE WEAK FRONTAL ZONE WILL LIKELY HAVE
WASHED OUT BY THU MORNING... AND THE SURFACE HIGH CENTERED OFF THE
SOUTHEAST COAST WILL INTRODUCE A MOIST CONFLUENT LOW LEVEL FLOW OFF
THE ATLANTIC INTO NC. A POSITIVELY TILTED TROUGH WILL SHIFT FROM
MT/DAKOTAS/SCENTRAL CANADA EARLY THU ACROSS ONT/QUE BY FRI NIGHT...
PROPELLING A COLD FRONT THROUGH THE GREAT LAKES/MID MISS VALLEY. AS
THE FLAT RIDGE HOLDS ACROSS THE SOUTHEAST/MIDSOUTH/GULF STATES
HOWEVER... WE`LL STAY WITHIN AN ENVIRONMENT CHARACTERIZED BY WEAK
SHEAR AND MODERATE INSTABILITY (TEMPERED BY WARM MID LEVELS). PW
VALUES SHOULD STAY ABOVE NORMAL AT 1.7-1.9"... NOT UNEXPECTED GIVEN
THE TROPICAL NATURE OF THE INCOMING AIR MASS... AND SUFFICIENT TO
SUPPORT SCATTERED CONVECTION ALONG THE SEA BREEZE... DYING FRONTAL
ZONE... OR ANY OTHER SUBTLE BOUNDARY. WILL RETAIN AFTERNOON AND
EVENING STORM CHANCES BOTH DAYS... WITH TEMPS HOLDING ABOUT A
CATEGORY ABOVE NORMAL AS THICKNESSES STAY AROUND 10 M ABOVE NORMAL.
FOR SAT-TUE: STILL EXPECT A TRANSITION FROM THE WARM/HUMID WEATHER
TO MORE SEASONABLE CONDITIONS LATE IN THE WEEKEND. THE INITIAL MID
LEVEL TROUGH OVER ERN QUEBEC WILL CONTINUE SHIFTING EAST OVER THE
MARITIMES... WHILE A STRONG SLUG OF STRONG VORTICITY EMANATING FROM
A STRONG COLD VORTEX OVER THE BEAUFORT SEA WILL PUSH EASTWARD CLOSE
ON ITS HEELS... CROSSING HUDSON BAY ON SUNDAY. THIS SHOULD PUSH THE
SURFACE COLD FRONT TO JUST NW OF NC BY SUN... AND WELL INTO THE
STATE BY EARLY MON. BOTH THE GFS AND ECMWF TRACK THEIR COOL PARENT
HIGHS OVER THE ST LAWRENCE VALLEY/SRN QUEBEC MON/TUE... WITH THE
COLD FRONT PUSHING TO ERN NC AND ACROSS NWRN SC. THIS MODEL
AGREEMENT LEADS TO GROWING CONFIDENCE THAT THE PARENT HIGH WILL BE
DENSE ENOUGH TO PUSH THIS COOLER AIR WELL INTO CENTRAL NC...
ALTHOUGH IT MAY NOT HAPPEN UNTIL LATE SUN NIGHT INTO MON MORNING.
WILL FOLLOW THIS TREND WITH TEMPS HOLDING ABOVE NORMAL SAT/SUN (BUT
NOT AS WARM IN THE NORTH SUN DUE TO MORE CLOUDS) WITH HIGHS IN THE
MID 80S TO NEAR 90... BUT THEN EXPECT TEMPS TO PLUNGE FOR MON/TUE
WITH THICKNESSES DROPPING TO 10-20 M BELOW NORMAL... YIELDING HIGHS
NEAR 80 TO LOWER 80S. REGARDING PRECIP CHANCES... WE`RE LIKELY TO
SEE SCATTERED TO PERHAPS NUMEROUS SHOWERS AND STORMS LATE SAT
THROUGH AT LEAST SUN NIGHT... BOTH ALONG THE PREFRONTAL PIEDMONT
TROUGH AND AHEAD OF AND WITH THE FRONT ITSELF. SHOWER/STORM CHANCES
ARE EXPECTED TO PEAK SUN AFTERNOON. WITH THE MID LEVEL TROUGH AXIS
SWINGING THROUGH THE REGION MON... WE MAY SEE LINGERING CHANCES FOR
RAIN ESPECIALLY SOUTH AND EAST. THE SURFACE RIDGE NOSING IN FROM THE
NORTH LATE MON INTO TUE ACCOMPANIED BY LOWERING PW VALUES SHOULD
MEAN MOSTLY DRY WEATHER TUE... AS THE MID LEVEL TROUGH AXIS LIFTS NE
AWAY FROM THE REGION FOLLOWED BY WEAK MID LEVEL SHORTWAVE RIDGING
OVER THE CAROLINAS. -GIH
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 110 PM TUESDAY...
SCATTERED SHOWERS AND STORMS CONTINUE ACROSS THE AREA... BUT ARE NOT
CURRENTLY AFFECTING ANY TERMINALS. A FEW STORMS ARE POSSIBLE THROUGH
THE OVERNIGHT HOURS AS A WEAK BOUNDARY APPROACHES THE AREA FROM THE
NORTHWEST. SUB-VFR CONDITIONS WITH LOW CLOUDS/FOG ARE POSSIBLE EARLY
WEDNESDAY AT KFAY AND KRWI WHERE LOW LEVEL MOISTURE REMAINS HIGH...
PARTICULARLY AT KFAY WHERE 1-2 INCHES OF RAIN FELL THIS EVENING.
SCATTERED CONVECTION WILL BE MORE PROMINENT WEDNESDAY AFTERNOON-
EVENING...MAINLY ACROSS THE SOUTHERN COUNTIES INCLUDING IN VICINITY
OF THE KFAY TERMINAL. OTHERWISE VFR CONDITIONS ARE EXPECTED
TYPICAL SUMMERTIME WEATHER CONDITIONS ANTICIPATED THURSDAY THROUGH
SATURDAY WITH AREAS OF EARLY MORNING FOG AND LOW CLOUDS GIVING WAY
TO VFR CONDITIONS ASIDE FROM SUB-VFR CONDITIONS IN VICINITY OF
SCATTERED AFTERNOON-EARLY EVENING CONVECTION. ON SUNDAY...A FRONT
WILL BE APPROACHING FROM THE NW. THIS WEATHER SYSTEM WILL LIKELY
ENHANCE THE PROBABILITY OF CONVECTION ACROSS CENTRAL NC.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD/WSS
NEAR TERM...BSD/WSS
SHORT TERM...WSS
LONG TERM...HARTFIELD
AVIATION...SEC/WSS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
305 PM EDT MON SEP 1 2014
.SYNOPSIS...AN AREA OF HIGH PRESSURE WILL EXTEND OVER THE REGION
THROUGH TUESDAY. A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS
CENTRAL NC ON WEDNESDAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA
FOR THE REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 305 PM MONDAY...
LATE THIS AFTERNOON THROUGH TONIGHT... SLIGHT TO MODERATELY UNSTABLE
COVERS CENTRAL NC AT MID AFTERNOON WITH A WEAK SHEAR AXIS SLOWLY
EDGING EASTWARD ACROSS THE REGION. BEST DYNAMICS/LIFT ASSOCIATED
WITH THIS FEATURE WELL NORTH OF OUR REGION AS SHEAR AXIS IS IMPEDING
UPON A MID-UPPER LEVEL RIDGE POSITIONED OVER EASTERN NC. THE RIDGE
WILL CONTINUE TO INHIBIT MOST CONVECTIVE DEVELOPMENT BUT COULD STILL
SEE AN ISOLATED STORM OR TWO DEVELOP ACROSS THE REGION. BASED ON 18Z
MESO-ANALYSIS...ISOLATED CONVECTIVE DEVELOPMENT APPEARS TO BE
FAVORED OVER THE WESTERN PIEDMONT...AND NEAR THE VIRGINIA BORDER
COUNTIES. THIS SCENARIO HAS THE SUPPORT OF THE LATEST HRRR (WHICH
HAS BEEN TRENDING WETTER). THE CONVECTIVE ALLOWING
MODELS...THOUGH...HAVE BEEN TRENDING DRIER AND NOW SUGGEST THAT
ISOLATED CONVECTION WILL OCCUR OUTSIDE OF OUR FORECAST AREA.
WILL LIKELY SEE PATCHES OF FOG DEVELOP AFTER MIDNIGHT...MAINLY OVER
THE COASTAL PLAIN..SANDHILLS AND EASTERN PIEDMONT. HOWEVER DENSE FOG
WILL BE RARE WITH BULK OF THE VISIBILITIES AT OR ABOVE 1-2 MILES.
MIN TEMPS OVERNIGHT NEAR 70-LOWER 70S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 305 PM MONDAY...
TUESDAY AND TUESDAY NIGHT... MID-UPPER LEVEL RIDGE PROJECTED TO
SLOWLY WEAKEN THIS PERIOD. THIS MAY ALLOW A FEW MORE T-STORMS TO
DEVELOP IN THE SLIGHT-MODERATELY UNSTABLE AIR MASS TUESDAY AFTERNOON-
EVENING. IN ADDITION...A S/W RESPONSIBLE FOR TRIGGERING THE
CONVECTION ACROSS PARTS OF THE MISSOURI VALLEY/OZARKS THIS AFTERNOON-
EVENING WILL APPROACH CENTRAL NC FROM THE NW LATE IN THE DAY. THIS
FEATURE MAY TRIGGER ADDITIONAL ISOLATED-SCATTERED CONVECTION TUESDAY
EVENING ACROSS THE NW PIEDMONT...AND OVERNIGHT TUESDAY INTO EARLY
WEDNESDAY OVER THE REMAINDER OF CENTRAL NC. WHILE FORCING IS BETTER
COMPARED TO THE PAST FEW DAYS...LIFT IS STILL CONSIDERED WEAK-
MARGINAL AT BEST. THUS WILL LIMIT POPS TO NO HIGHER THAN LOW CHANCE.
ANOTHER HOT DAY IN STORE FOR THE REGION. AFTERNOON THICKNESSES WILL
REMAIN 20-25M ABOVE NORMAL...SUPPORTIVE OF HIGH TEMPS IN THE LOW-MID
90S UNDER FULL SUN CONDITIONS. WHEN THE HUMIDITY IS FACTORED
IN...HEAT INDEX VALUES NEAR 100-104 WILL BE COMMON WITH THE HIGHEST
H.I.VALUES IN THE SOUTHERN COASTAL PLAIN AND SANDHILLS. MIN TEMPS
TUESDAY NIGHT GENERALLY IN THE LOWER 70S. -WSS
FOR WED/WED NIGHT: THE WEAK SURFACE REFLECTION THAT REMAINS FROM THE
COLD FRONT APPROACHING CENTRAL NC WILL BECOME EVEN MORE WASHED OUT
AS IT SHIFTS INTO THE LEE TROUGH OVER CENTRAL NC. MODELS SHOW A VERY
WEAK VORTICITY LOBE ASSOCIATED WITH THIS FRONT PUSHING ESE THROUGH
NC EARLY WED... AND ITS APPROACH ALONG WITH LINGERING STRONG LOW
LEVEL MOISTURE TRANSPORT OVER ERN NC SHOULD SUPPORT AN AREA OF
ATYPICAL MORNING SHOWERS/STORMS OVER THE ERN AND ESPECIALLY SE CWA
WED MORNING. THE DEPARTURE AND DAMPENING OF THE MEAN MID LEVEL
TROUGH WELL TO OUR NE WILL RESULT IN MODEST RISING HEIGHTS (15-25 M)
WITHIN THE FLAT (W-E ORIENTED) MID LEVEL RIDGE ACROSS NC THROUGH WED
NIGHT. THE LATEST NAM RUN IS CONSISTENT WITH PREVIOUS RUNS IN
BRINGING LOWER PW (UNDER 1.5") INTO MUCH OF THE CWA FROM THE NW WITH
A BIT STRONGER 850-700 MB NW WIND AS COMPARED TO THE GFS... WHICH
KEEPS PW VALUES UP TO 1.7-1.9". GIVEN THE FACT THAT THE MID LEVEL
TROUGH WILL BE DAMPENING WITH LITTLE REASON TO SUPPORT A STRONG PUSH
OF DRY AIR PAST THE MOUNTAINS... THE GFS`S MORE SUBDUED TROUGH
INFLUENCE APPEARS MORE LIKELY... BASED ON THE PERSISTENCE OF THE
STRONG RIDGE. MODERATE INSTABILITY IS EXPECTED OVER ALL BUT PERHAPS
THE FAR NW... WITH THE GFS SHOWING MUCAPE PEAKING AT 1000-2500 J/KG.
WILL STAY CLOSE TO THE GFS/ECMWF SOLUTION WITH SCATTERED AFTERNOON
THROUGH EVENING STORMS... WITH BEST COVERAGE ACROSS THE SOUTHERN CWA
AND ALONG/EAST OF THE PERSISTENT LEE TROUGH... AS WELL AS ALONG THE
INLAND-TRACKING SEA BREEZE. WITH ABOVE-NORMAL PW AND WEAK MID LEVEL
FLOW... SLOW-MOVERS AND HEAVY-RAINERS ARE POSSIBLE. WITH THICKNESSES
A TAD LOWER THAN TUE BUT REMAINING 12-20 M ABOVE NORMAL... EXPECT
WARM AND STICKY HIGHS OF 91-95... DESPITE A GOOD CHANCE OF DEBRIS
CLOUD COVER THROUGH THE DAY. CONVECTION CHANCES SHOULD RECEDE WED
NIGHT BUT THE GFS INDICATES PLENTY OF ELEVATED BUOYANCY POTENTIAL
OVERNIGHT... INCLUDING MLCAPE OF 500-1000 J/KG RESULTING FROM VERY
WARM 960-920 MB TEMPS. WILL HOLD ONTO CHANCE POPS MAINLY SOUTH HALF
OVERNIGHT. MUGGY LOWS IN THE LOW-MID 70S. -GIH
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 230 PM MONDAY...
FOR THU/FRI: CONTINUED ABOVE-NORMAL WARMTH WITH ONLY MINOR CHANGES
IN AIR MASS. AT THE SURFACE... THE WEAK LEE TROUGH HOLDS THROUGH
CENTRAL NC... ALONG WITH A HUMID AND SOMEWHAT STAGNANT AIR MASS. A
POSITIVELY TILTED TROUGH SHIFTS THROUGH THE PACIFIC NORTHWEST AND SW
CANADA INTO THE DAKOTAS THU... RESULTING IN BUILDING HEIGHTS AND
GRADUAL MID LEVEL WARMING OVER THE SOUTHEAST STATES. THIS POLAR
STREAM TROUGH THEN SHIFTS INTO ERN CANADA... WHILE THE FLAT RIDGE
HOLDS ACROSS NC. WITH PLENTY OF LOW LEVEL MOISTURE POOLING...
ISOLATED TO SCATTERED STORMS FOCUSED ALONG A SEA BREEZE OR SOME
OTHER SUBTLE BOUNDARY REMAIN A GOOD BET... DESPITE THE WARMING TEMPS
ALOFT. WILL RETAIN AFTERNOON AND EVENING STORM CHANCES BOTH DAYS...
WITH TEMPS HOLDING ABOUT A CATEGORY ABOVE NORMAL AS THICKNESSES STAY
10-15 M ABOVE NORMAL.
FOR SAT THROUGH MON: A PATTERN TRANSITION IS LIKELY NEXT WEEKEND.
THE INITIAL MID LEVEL TROUGH CONTINUES HEADING EASTWARD OVER ERN
CANADA EARLY SAT... HOWEVER A SLUG OF STRONG VORTICITY EMANATING
FROM A STRONG COLD VORTEX OVER THE BEAUFORT SEA WILL PUSH EASTWARD
CLOSE ON ITS HEELS... TAKING A COLD FRONT TO NEW ENGLAND AND THE OH
VALLEY BY EARLY SAT. THE RESULTING TROUGH OVER ERN NOAM SUNDAY
SHOULD HELP PUSH THE FRONT SOUTHWARD INTO NC... AFTER WHICH TIME IT
IS APT TO LAY WEST/EAST AND STALL OVER THE CAROLINAS FOR LATE SUN
THROUGH MON. THE GFS HAS A STRONGER/FASTER TIME FRAME THAN THE
ECMWF... WITH THE FORMER MODEL SOLUTION TAKING THICKNESSES MUCH
COLDER... UP TO 25 M BELOW NORMAL AS OPPOSED TO THE ECMWF WHICH IS
BARELY 5 M BELOW NORMAL. TOUGH TO RESOLVE SUCH DIFFERENCES BUT GIVEN
THE STRENGTH OF THE SRN CONUS RIDGE... AND THE FAR-NORTH TRACK OF
THE POLAR LOW... I REMAIN SKEPTICAL ABOUT A STRONG COLD FRONTAL
PASSAGE THROUGH NC. WILL STAY ON THE CONSERVATIVE SIDE OF THE TEMP
TREND... WITH HIGHS/LOWS INITIALLY AROUND 90/AROUND 70 SAT...
SLIPPING TO LOW-MID 80S/UPPER 60S BY MON. PRECIP CHANCES AND
PATTERNS ARE LIKELY TO CHANGE LITTLE THROUGH SUN... PERHAPS
INCREASING IN COVERAGE AS THE FRONT APPROACHES WITH FALLING HEIGHTS
ALOFT... STRENGTHENING (YET STILL SOMEWHAT WEAK) MID LEVEL FLOW...
AND A PERSISTENT CONFLUENT INFLUX OF GULF AND ATLANTIC MOISTURE IN
THE LOW LEVELS. WILL MAINTAIN SCATTERED SHOWERS AND STORMS FOCUSED
ON -- BUT NOT RESTRICTED TO -- AFTERNOON AND EVENING HOURS. WILL
KEEP A CLIMO CHANCE POP ON MON... WITH LOWER THAN USUAL CONFIDENCE
AS CONVECTION WILL GREATLY DEPEND ON WHETHER THE FRONT HOLDS UP
ACROSS NC OR SHIFTS TO OUR SOUTH. -GIH
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 120 PM MONDAY...
VFR CONDITIONS WILL CONTINUE ACROSS MUCH OF CENTRAL NC THROUGH
TUESDAY NIGHT. THE EXCEPTION WILL BE A GOOD PROBABILITY OF EARLY
STRATUS AND FOG (AND ASSOCIATED IFR/LIFR CONDITIONS)OCCURRING NEAR
KRWI...KFAY AND POTENTIALLY NEAR KRDU. THE FOG/STRATUS WILL BE MOST
LIKELY BETWEEN 09Z-12Z.
ANY CONVECTION THIS AFTERNOON WILL BE LIMITED TO THE SEABREEZE WHICH
MAY TRIGGER AN ISOLATED THUNDERSTORM NEAR OR SOUTH OF KGSB AND KRWI
AND TO THE EAST-SE OF KFAY. THE SAME STORY WILL HOLD FOR TUESDAY
AFTERNOON THOUGH AN ISOLATED THUNDERSTORM MAY OCCUR IN VICINITY OF
KINT AND KGSO LATE IN THE DAY INTO THE EVENING HOURS.
THE WEATHER PATTERN MAY BECOME A LITTLE MORE UNSETTLED WEDNESDAY AS
A WEAK SURFACE BOUNDARY WILL DRIFT INTO CENTRAL NC. THIS FEATURE
WILL SERVE AS A FOCUS FOR THE DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS...MAINLY IN THE AFTERNOON-EVENING HOURS. THIS BOUNDARY
IS PROJECTED TO WEAKEN THURSDAY WHILE HIGH PRESSURE WILL BUILD BACK
INTO THE REGION FRIDAY AND SATURDAY. OTHERWISE...THE OCCURRENCE OF
EARLY MORNING FOG/STRATUS WILL CONTINUE THROUGH THE PERIOD.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS
SHORT TERM...WSS/HARTFIELD
LONG TERM...HARTFIELD
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1256 PM EDT MON SEP 1 2014
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND OVER THE AREA THROUGH TUESDAY. A
WEAK COLD FRONT WILL APPROACH THE AREA FROM THE NORTH
WEDNESDAY...THEN STALL AND DISSIPATE THURSDAY AND FRIDAY. HIGH
PRESSURE RIDGES INTO THE REGION FROM OFFSHORE FRIDAY AND
SATURDAY...THEN ANOTHER COLD FRONT WILL DROP INTO THE AREA LATE IN
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1230 PM MONDAY...MADE MINOR ADJUSTMENTS TO NEAR TERM WX/POP
GRIDS. WITH THE LATEST MOS GUIDANCE AND HRRR MODEL HAVE DECREASED
POPS MAINLY ACROSS THE COASTAL PLAINS. SHOULD STILL SEE SHOWERS
AND THUNDERSTORMS TO DEVELOP ALONG THE SEA BREEZE LATER THIS
AFTERNOON. HIGHS ARE EXPECT TO BE IN THE LOW 90S INLAND TO MID 80S
TO AROUND 90 NEAR THE COAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
AS OF 330 AM MONDAY...WEAK SHRT WV MOVING ACROSS SUPPORTS ISOLD TSTM
THREAT ALONG AND E OF HWY 17 OVERNIGHT...OTHERWISE A REPEAT OF WARM
AND MUGGY CONDITIONS OF PAST FEW NIGHTS. MIN TEMPS FROM MID 70S
INLAND TO NEAR 80 COAST.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 345 AM MON...THE UPPER RIDGE FLATTENS TUES INTO WED AS A
STRONGER SHORTWAVE MOVES ACROSS THE OHIO RIVER VALLEY AND THROUGH
NEW ENGLAND. MAINLY ISOL CONVECTION TUES WITH LIMITED FORCING BUT
BETTER CHANCES WED AFTERNOON THROUGH THURS AS A BACKDOOR COLD FRONT
DROPS INTO AND STALLS ACROSS THE AREA. UPPER LEVEL DYNAMICS REMAIN
RATHER WEAK WITH THE CORE OF THE UPPER JET REMAINING WELL NORTH OF
THE REGION BUT PLENTY OF MOISTURE WILL BE IN PLACE WITH MODERATE TO
STRONG INSTABILITY TO ALLOW FOR SCT SHOWERS AND THUNDERSTORMS...
ESPECIALLY INVOF THE FRONT WHERE BETTER SFC CONVERGENCE WILL RESIDE.
SHEAR AND MID LEVEL LAPSE RATES REMAIN RATHER WEAK SO SEVERE CHANCES
WILL REMAIN LOW BUT COULD SEE LOCALLY HEAVY PRECIP WITH WEAK
STEERING FLOW AND HIGH PWATS.
THE FRONTAL BOUNDARY DISSIPATES LATE THURS INTO FRI WITH HIGH PRES
STRENGTHENING OFFSHORE AND UPPER RIDGING BUILDING ALOFT AND EXPECT
MAINLY ISOLATED DIURNALLY DRIVEN CONVECTION FRI INTO SAT. THE UPPER
RIDGE IS SUPPRESSED AGAIN LATE IN THE WEEKEND WITH ANOTHER SHORTWAVE
TRAVERSING ACROSS THE GREAT LAKES INTO NEW ENGLAND WITH THE
ATTENDANT BACKDOOR COLD FRONT MOVING INTO THE REGION SUN BRINGING
BETTER CHANCES OF SHOWERS AND THUNDERSTORMS.
LOW LEVEL THICKNESSES SUPPORT HIGHS IN THE LOW TO MID 90S THROUGH
MUCH OF THE EXTENDED WHICH IS ABOUT 5 TO AS MUCH AS 10 DEGREES ABOVE
CLIMO. WARMEST DAYS LOOK TO BE TUES AND WED WHEN LOW LEVEL
THICKNESSES ARE GREATEST. SLIGHT COOLING THURS WITH GREATER CLOUD
COVER...ESPECIALLY NORTHERN AREA WHERE NE/ELY FLOW EXPECTED NORTH OF
THE BACKDOOR COLD FRONT...HOWEVER WINDS EXPECTED TO BE RATHER LIGHT.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
SHORT TERM /THROUGH 12Z TUESDAY/...
AS OF 1 PM MON...VFR CONDITIONS WILL DOMINATE MOST OF THE TAF PERIOD
UNDER HIGH PRESSURE. ISOLATED SHOWERS/THUNDERSTORMS MAY DEVELOP
THIS AFTERNOON MAINLY AFFECTING THE COASTAL TAF SITES (EWN/OAJ).
MAY AGAIN SEE SOME PATCHY FOG/STRATUS CONDITIONS LATE TONIGHT INTO
THE EARLY MORNING HOURS...BRINGING CONDITIONS TO MVFR FOR ALL TAF
SITES EXCEPT EWN. ANY FOG/STRATUS WILL START TO MIX OUT AFTER
SUNRISE...BRING CONDITIONS BACK TO VFR.
LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 345 AM MON...GENERALLY VFR CONDITIONS EXPECTED THROUGH THE
LONG TERM ALTHOUGH PATCHY LIGHT FOG POSSIBLE DURING THE EARLY
MORNING HOURS. ISOL-SCT CONVECTION POSSIBLE EACH DAY WITH BEST
CHANCES WED THROUGH THURS AS A BACKDOOR FRONT DROPS INTO THE REGION.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 1230 PM MON...NO CHANGES TO FORECAST. THE LATEST BUOY OBS
ARE SHOWING SW WINDS 5 TO 15 KTS WITH SEAS 2 TO 3 FEET. SW WINDS
WILL CONTINUE UNDER THE PERSIST BERMUDA HIGH AND INLAND TROF
PATTERN THROUGH THE PERIOD. SPEEDS WILL DIMINISH TO 10-15 KT THIS
MORNING...THEN INCREASE TO 15-20 KT LATE AFTN INTO THIS
EVENING...DIMINISHING AGAIN LATE TONIGHT.
WW3 INITIALIZED BETTER WITH SEAS MAINLY AROUND 3 FT...AND ADJUSTED
FCST ACCORDINGLY. HEIGHTS BUILDING TO AROUND 4 FT OUTER PORTIONS OF
CENTRAL AND NRN WATERS THIS AFTN AND EVENING.
LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 345 AM MON...THE BERMUDA HIGH OFFSHORE WILL BRING S/SW WINDS
ACROSS THE WATERS INTO WED. WINDS GENERALLY AROUND 5-15 KT DURING
LATE NIGHT AND MORNING HOURS BUT GRADIENTS TIGHTEN DURING THE
AFTERNOON AND EVENING HOURS BOTH MON AND TUES AS THE PIEDMONT
THERMAL TROUGH STRENGTHENS ALLOWING WINDS TO INCREASE TO AROUND
10-20 KT. A BACKDOOR FRONT DROPS INTO THE REGION WED THROUGH THURS
BRINGING LIGHT WINDS...GENERALLY LESS THAN 10 KT. WINDS NORTH OF THE
FRONT EXPECTED TO BE E TO NE WHILE REMAINING S/SW TO THE SOUTH. THE
FRONT IS PROGGED TO DISSIPATE BY FRI WITH SLY FLOW AROUND 5-10
RETURNING TO ALL WATERS. MODELS IN GOOD AGREEMENT KEEPING SEAS
AROUND 2-4 FT...LOCALLY TO 5 FT NEAR DIAMOND SHOALS...INTO EARLY WED
BUT THEN SUBSIDE TO AROUND 2 FT THURS AND FRI WITH LIGHT WINDS
ACROSS THE WATERS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM/BM
SHORT TERM...JBM
LONG TERM...SK
AVIATION...JBM/SK/BM
MARINE...JBM/SK/BM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1129 PM CDT SUN AUG 31 2014
.UPDATE...
ISSUED AT 1115 PM CDT SUN AUG 31 2014
NO MAJOR CHANGES PLANNED...SHOULD BE A DRY NIGHT. THERE COULD BE
SOME PATCHY FOG WHERE SKIES CLEAR...BUT FOR NOW FEEL ITS NOT WORTH
A MENTION WITH THE HRRR NOT INDICATING ANY LOW VSBYS...BUT
SOMETHING FOR THE MID SHIFT TO WATCH.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 305 PM CDT SUN AUG 31 2014
AS OF 20Z...THE REGION IS IN A RELATIVELY QUIET PERIOD BETWEEN
UPPER WAVES (ALTHOUGH AREAS OF DRIZZLE/LIGHT RAIN MAY BE
PERSISTING). THE NEXT WAVE WILL PROPAGATE INTO THE REGION FROM THE
SOUTHWEST...AND SPREAD SHOWERS INTO PORTIONS OF THE SOUTHERN FA.
MOST GUIDANCE SUGGESTS COVERAGE WILL DISSIPATE AS THE STRONGER
ACTIVITY INITIATES ACROSS NEBRASKA/IOWA. LATEST MESOSCALE ANALYSIS
INDICATES MLCAPE AOA 1000 J/KG ALONG AND EAST OF A LINE FROM KBJI
TO KBWP. HOWEVER...MLCIN IS STILL 60-80 J/KG...AND ANTICIPATE THIS
AIRMASS TO BE EAST OF THE FA (AS MORE STABLE/DRIER AIR ADVECTS IN
FROM THE WEST) BY THE TIME MLCIN IS WEAK ENOUGH FOR THUNDER
INITIATION. STILL CANNOT RULE OUT AN ISOLD SHOWER/STORM THIS
EVENING...BUT CHANCES APPEAR VERY LOW (AND HIGH RES MODELS AGREE).
MUCH OF TONIGHT INTO MONDAY WILL BE DRY. HOWEVER...THE REGION DOES
REMAIN IN GENERAL CYCLONIC FLOW ALOFT...AND THERE SHOULD BE WEAK
UPPER WAVES ROTATING THROUGH THE REGION. DID INTRODUCE SLIGHT
THUNDER CHANCES FOR MONDAY AFTERNOON/EVENING WHEN MODELS AGREE ON
A STRONGER UPPER WAVE THAT WOULD INTERACT WITH WEAK INSTABILITY
FROM DAYTIME HEATING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 305 PM CDT SUN AUG 31 2014
TUESDAY-WEDNESDAY...MUCH LIKE THE SHORT TERM PERIOD...WEAK UPPER
WAVES IN THE UPPER FLOW PATTERN COULD LEAD TO PRECIP...BUT MOST
AREAS SHOULD BE DRY A MAJORITY OF THE PERIOD. THE MAIN CONCERN
WILL BE WEDNESDAY AFTERNOON AS MODELS INDICATE A WARM FRONTAL TYPE
BOUNDARY LIFTING INTO WEST CENTRAL MINNESOTA...WHICH MAY LEAD TO
STRONGER THUNDERSTORM POTENTIAL.
WEDNESDAY NIGHT-SUNDAY...LONG TERM MODELS ARE IN GOOD AGREEMENT
WITH OVERALL UPPER AIR PATTERN AND PLACEMENT OF PRECIP FOR MID
WEEK CHANCES OF CONVECTION. BOTH MODELS SHOWING AN UPPER
LOW/TROUGH OVER SRN SASK AROUND 06Z THU MOVE INTO WRN ONTARIO BY
00Z FRI. SW FLOW OVER THE DAKOTAS WILL BRING A CHANCE OF
CONVECTION TO NORTHERN AND NORTHEASTERN ZONES WED NIGHT THROUGH
THU NIGHT. NW FLOW THEN RETURNS WITH A COOL AND DRY AIRMASS IN
PLACE...BRINGING COOLER THAN NORMAL TEMPS TO THE REGION. THIS DRY
PERIOD SHOULD BE IN PLACE BY FRI AND CONTINUE THROUGH NEXT WKND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1115 PM CDT SUN AUG 31 2014
EXPECT VFR CONDITIONS WITH THE CHANCE OF SOME PATCHY FOG LATER
TONIGHT WHERE IT CLEAR. FOR NOW WILL NOT MENTION ANY FOG...BUT
SOMETHING TO KEEP IN MIND. THERE WILL BE A FEW SHOWERS AND STORMS
MONDAY AFTERNOON MOVING FROM WEST TO EAST. WILL MENTION SOME VCSH
IN THE 19-3Z TIMEFRAME...BUT HOLD OF ON THUNDER MENTION WITH
FAIRLY ISOLATED COVERAGE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...DK
SHORT TERM...TG
LONG TERM...TG/SPEICHER
AVIATION...DK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
921 PM EDT TUE SEP 2 2014
.SYNOPSIS...
HIGH PRESSURE WILL BUILD NORTHEAST UP THE APPALACHIAN MOUNTAINS
THROUGH WEDNESDAY NIGHT AND OFF THE EAST COAST BY THURSDAY NIGHT. A
WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA THURSDAY FOLLOWED BY
A COLD FRONT FRIDAY EVENING. HIGH PRESSURE WILL BUILD SOUTHEAST
ACROSS THE REGION INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CONVECTION WITH DIFFUSE COLD FRONT NOW REDUCED TO 3 SMALL CLUSTERS.
VERY LITTLE LIGHTNING OCCURRING. RUC HANGS ON TO A FEW CELLS THRUT
THE NIGHT SO WILL SLOW POP DROP OFF ENOUGH TO KEEP SLIGHT CHANCE
GOING LONGER INTO THE NIGHT.
MUCH OF THE CLOUD COVER FROM EARLIER IN THE DAY HAS DISSIPATED
LEAVING PATCHY LOWER CLOUDS WITH BAND OF JET INDUCED CIRRUS ABOVE.
WEAK COLD ADVECTION LOOKS EVEN MORE LIKELY TO NOT BE STRONG ENOUGH
TO BRING IN THE DRIER AIR AS QUICK AS THOUGHT EARLIER SO WILL INCH
LOWS UP EVEN ANOTHER DEG OVER THE SE 2/3 OF THE AREA.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/...
BROAD UPPER LEVEL TROUGH WILL MOVE EAST OF THE AREA OVERNIGHT
SETTING UP A ZONAL FLOW ACROSS THE COUNTRY ONCE AGAIN. SURFACE HIGH
WILL BUILD NORTHEAST AND THEN EAST OF THE AREA BY WEDNESDAY NIGHT.
WARM AIR ADVECTION WILL RESUME ON THURSDAY WITH A PRETTY GOOD SURGE
OF WARM AIR RACING NORTHEAST INTO THE FORECAST AREA. 850 MB
TEMPERATURES RISE FROM 16C WEDNESDAY NIGHT TO 20C BY FRIDAY.
INCREASED DEW POINT AIR WILL RETURN AND BRING WITH IT HIGHER
HUMIDITY ON FRIDAY.
COLD FRONT IS EXPECTED TO MOVE EAST ACROSS THE REGION FRIDAY
EVENING. CONVECTION IS EXPECTED TO REMAIN ASSOCIATED WITH THE COLD
FRONT FRIDAY AFTERNOON INTO FRIDAY NIGHT. OTHERWISE...NO MAJOR
THREAT FOR SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED PERIOD
UNTIL FRIDAY AFTERNOON. WILL HAVE TO KEEP AN EYE ON THE COLD FRONT
FRIDAY FOR SEVERE POTENTIAL DUE TO IDEAL TIMING IN THE HEAT OF THE
DAY.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
A SURFACE COLD FRONT WILL BE JUST ABOUT OUT OF THE AREA AT DAYBREAK
SATURDAY. THERE COULD BE A FEW SHOWERS ALONG AND BEHIND THE FRONT
BUT RAPID DRYING WILL OCCUR DURING THE AFTERNOON. READINGS NEXT
WEEKEND WILL BE BACK BELOW NORMAL WITH LOWS MONDAY MORNING POSSIBLY
GETTING INTO THE 40S. SUNDAY WILL BE A PLEASANT DAY WITH ABUNDANT
SUNSHINE. THE FALL LIKE WEATHER WILL CONTINUE ON MONDAY. THE
SURFACE HIGH RESPONSIBLE FOR THE QUIET WEATHER WILL EVENTUALLY MOVE
OFF TO THE EAST ON TUESDAY ALLOWING WARMER SOUTHERLY FLOW TO
RETURN. EXPECT TEMPS TUESDAY TO AVERAGE NEAR NORMAL. PRECIP
CHANCES SHOULD HOLD OFF TILL JUST AFTER THE PERIOD ENDS.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
THE COLD FRONT WILL SAG ACROSS THE AREA THIS EVENING WITH A FEW
MORE SHOWERS THAT MAY PRODUCE BRIEF MVFR CONDITIONS. THE DRIER AIR
WILL BE SLOW TO FILTER IN AND THE WIND WILL BECOME LIGHT AND FOG
IS LIKELY IN MANY AREAS BY DAYBREAK. STRATUS IS ALSO POSSIBLE...
MAINLY AT INLAND SITES AND IFR CONDITIONS MAY OCCUR FOR SEVERAL
HOURS INTO MID MORNING. THE FOG AND STRATUS SHOULD
DISSIPATE...PERHAPS EVOLVING INTO A CUMULUS FIELD (SCT-BKN035-045)
FOR A WHILE. VFR CONDITIONS SHOULD PREVAIL BY LATE MORNING
EVERYWHERE. LAKE BREEZE WIND SHIFTS LIKELY AT KCLE AND KERI.
OUTLOOK...NON VFR LIKELY IN SHOWERS AND THUNDERSTORMS BY FRIDAY
EVENING INTO SATURDAY WITH THE NEXT COLD FRONT.
&&
.MARINE...
A SURFACE COLD FRONT WILL MOVE EAST OF THE LAKE BY EARLY THIS
EVENING. LINGERING SHOWERS OVER THE LAKE WILL ALSO BE GONE BY THAT
TIME. EXPECT THE FLOW TO BECOME WESTERLY BEHIND THE FRONT AND THEN
LIGHT AND VARIABLE OVERNIGHT. LIGHT FLOW WILL THEN CONTINUE
WEDNESDAY WITH SOUTHERLY FLOW DEVELOPING ON THURSDAY AS A SURFACE
RIDGE PUSHES EAST OF THE LAKE. SOUTH TO SOUTHWEST FLOW WILL THEN
GRADUALLY INCREASE AHEAD OF A COLD FRONT THAT WILL DROP SOUTH ACROSS
THE LAKE EARLY SATURDAY. MORE PRECIP IS LIKELY WITH THIS FRONT WITH
THE FLOW BECOMING NORTH BEHIND IT. DO NOT THINK SPEEDS WILL BE
STRONG ENOUGH FOR SMALL CRAFT HEADLINES. NORTHERLY FLOW WILL
CONTINUE THROUGH SUNDAY. SPEEDS MOST IF NOT THE ENTIRE PERIOD WILL
BE UNDER 15 KNOTS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY/ADAMS
SHORT TERM...LOMBARDY
LONG TERM...KUBINA
AVIATION...KOSARIK
MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS TULSA OK
329 PM CDT MON SEP 1 2014
.DISCUSSION...
A PROGRESSIVE...LOW AMPLITUDE SHORTWAVE TROUGH IS SLIDING EAST
ACROSS THE NORTH CENTRAL PART OF THE COUNTRY TODAY. A PAIR OF
EMBEDDED VORTICITY MAXIMA EXIST...ONE LIFTING QUICKLY NORTHEAST
INTO THE GREAT LAKES...AND ANOTHER MOVING ACROSS WY ATTM.
NORTHEAST OK/NORTHWEST AR LIES ON THE SOUTHERN FRINGE OF THE
DECENT WESTERLY FLOW IN THE MID LEVELS. AT THE SURFACE...A MORE
COMPLEX PATTERN EXISTS DUE TO OVERNIGHT CONVECTION THAT WAS MORE
EXTENSIVE THAN FORECAST. THE OUTFLOW BOUNDARY FROM THAT CONVECTION
HAS BEEN RETREATING NORTH DURING THE AFTERNOON AND IS
APPROACHING THE KANSAS BORDER. MEANWHILE...THE SYNOPTIC COLD FRONT
HAS BECOME NEARLY STATIONARY ACROSS CENTRAL AND SW KS. THE HRRR
HAS BEEN CONSISTENT ALL DAY IN DVLPNG STORMS BTWN 22-00Z IN THE
ZONE BTWN THE TWO BOUNDARIES. DIRECTIONAL/SPEED SHEAR SHOULD BE
GREAT ENOUGH TO SUPPORT SUPERCELLS...ESPECIALLY GIVEN AVAILABLE
CAPE. LOW LEVEL BACKED WINDS IN BTWN THE TWO BOUNDARIES
SUGGESTS...IF A SUPERCELL CAN GET GOING...THAT A LARGE HAIL/TORNADO
RISK EXISTS BEFORE CELLS GRADUALLY CONGEAL INTO CLUSTERS AND THEN
MOVE E/SE THIS EVENING...WHEN THE MAIN THREAT BECOMES DAMAGING
WINDS. MORE DEVELOPMENT IS FORECAST BY THE HRRR LATER TONIGHT
NORTH OF THE EFFECTIVE BOUNDARY. THERE WILL BE A SHARP CUTOFF AS
YOU GO SOUTH WHERE RAIN FALLS AND WHERE IT DOESN`T...GIVEN STRONG
CAP IN PLACE DUE TO EML.
I BACKED OFF SOME ON LOWS TONIGHT ACROSS THE NE OK AND NW AR GIVEN
POTENTIAL FOR CONVECTIVELY COOLED OUTFLOW...MUCH LIKE LAST NIGHT.
RAIN/STORM CHANCES WILL CONTINUE INTO TUESDAY MAINLY ACROSS NE
OK/NW AR NEAR AND NORTH OF THE EFFECTIVE BOUNDARY...WHICH WILL
BEGIN TO RETREAT AGAIN TOMORROW AND ESPECIALLY TOMORROW NIGHT. THE
BEST CHANCES FOR RAIN/STORMS TUESDAY NIGHT WILL BE NORTH AND EAST
OF TULSA IN THE WARM ADVECTION REGIME. PRECIP CHANCES COME TO AN
END WEDNESDAY AS THE BOUNDARY LIFTS NORTH OF THE REGION AND MID
LEVEL HEIGHTS RISE. GUSTY SOUTHWEST WINDS WILL PUSH TEMPS BACK
INTO THE UPPER 90S WEDNESDAY AFTERNOON ACROSS NE OK.
THE DETERMINISTIC RUNS OF THE GFS/ECMWF TODAY ARE SLOWER WITH THE
FRONT TOWARD THE END OF THE WEEK...GFS MORE SO THAN THE ECMWF.
NEVERTHELESS...POPS WILL BE CARRIED FRIDAY AND
SATURDAY...GRADUALLY TAPERING OFF SUNDAY. TEMPS WILL FALL BACK
INTO THE 80S FOR HIGHS AND 60S FOR LOWS.
THE RATHER ACTIVE PATTERN ACROSS THE NORTHERN TIER OF STATES
CONTINUES INTO NEXT WEEK...AS ANOTHER STRONG SYSTEM MOVES ACROSS
THE NORTHERN PART OF THE COUNTRY. AN EVEN STRONGER FRONT COULD BE
ON THE WAY IN ABOUT 10 DAYS...A SIGN OF THE CHANGE IN SEASONS.
LACY
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 71 91 75 96 / 60 40 20 10
FSM 75 91 73 94 / 30 40 20 10
MLC 77 93 76 93 / 30 30 10 10
BVO 69 90 69 96 / 60 40 30 10
FYV 71 86 69 91 / 60 50 30 20
BYV 71 86 69 91 / 60 50 30 20
MKO 73 90 72 93 / 50 40 20 10
MIO 71 88 72 94 / 60 40 40 10
F10 74 92 74 93 / 40 30 20 10
HHW 75 94 74 95 / 10 10 10 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
LONG TERM....30
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
815 PM EDT TUE SEP 2 2014
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE AREA THIS EVENING. HIGH
PRESSURE WILL BUILD ALONG THE EAST COAST LATE THIS WEEK...THEN
ANOTHER COLD FRONT WILL LIKELY PUSH SOUTH ACROSS THE REGION BY
SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
SENT ANOTHER UPDATE TO BEGIN TRIMMING BACK THE WATCH AS THE LINE
MOVES INTO CENTRAL PA.
MAIN LINE OF CONVECTION EXTENDS FROM SULLIVAN COUNTY BACK TO
SOUTHERN CAMBRIA. OVERALL THE ACTIVITY SEEMS TO BE WEAKENING. IF
THIS TREND CONTINUES...WE WILL CONTINUING CANCELING COUNTIES OUT
OF THE WATCH.
BIGGER QUESTION SWITCHES TO HOW MUCH ADDITIONAL CONVECTION WE CAN
EXPECT FOR THE REMAINDER OF THE EVENING IN THE AREAS WORKED OVER
BY THE EARLIER LINE OF STORMS. LATEST HRRR SHOWS ACTIVITY DROPPING
OFF SMARTLY AFTER SUNDOWN SO I HAVE STARTED LOWERING THE EVENING
AND OVERNIGHT POPS.
DRIER AIR BEHIND THE COLD FRONT WILL REPLACE THE SULTRY LATE
SEASON HUMIDITY WE HAVE EXPERIENCED FOR THE LAST SEVERAL DAYS. IT
WILL STILL BE RATHER MILD WITH LOWS IN THE 60S. CLEARING
SKIES...A LIGHT WIND WIND AND WET GROUND WILL LIKELY LEAD TO
AREAS OF FOG LATE TONIGHT.
HIGH PRES AND ASSOC DRIER AIR MASS WILL BE OVR THE AREA
WEDNESDAY...SUPPLYING MSUNNY AND WARM CONDS. ENS MEAN 8H TEMPS NR
15C SHOULD SUPPORT MAX TEMPS FROM THE M70S NW MTNS TO THE M80S
IN THE SUSQ VALLEY.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
IT WILL CONTINUE FAIR WEDNESDAY NIGHT WITH LITTLE MORE THAN AREAS
OF LATE NIGHT FOG AS THE ONLY REAL SENSIBLE WEATHER.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
SUBTROPICAL RIDGE CENTERED OVER THE CAROLINAS WILL BE SUPPRESSED BY
SHORTWAVE ENERGY AND MODERATE-INTENSITY SFC CYCLONE TRACKING NEWD
FROM THE NRN HIGH PLAINS ACROSS WRN ONTARIO INTO NRN QUEBEC THU THRU
SAT. ITS TRAILING COLD FRONT REMAINS THE FOCUS FOR PCPN HEADING INTO
THE WEEKEND WITH CONTINUED UNCERTAINTY IN THE SEWD FRONTAL
PROGRESSION. A SLOWER TREND MAY BE EMERGING IN THE 12Z GFS/GEFS WITH
ITS FRONTAL ZONE ALIGNING CLOSER WITH THE ECMWF/GEM BY 00Z SUN. MAX
POPS SHIFT FROM NW TO SE OVER THE CWA FROM 00Z SAT TO 00Z SUN. AHEAD
OF CDFRONT...TEMPS ARE LIKELY TO PEAK ON FRIDAY WITH MEAN H85 TEMPS
+18-20C SUPPORTING WIDESPREAD HIGHS 85-90F.
THE NEXT QUESTION CONCERNS HOW QUICKLY THE FRONT CLEARS SRN PA ON
SUNDAY WITH MODEL DATA SUGGESTING THE UPPER LEVEL FRONT HANGS
BACK ALONG THE APPLCHNS/MID-ATLC PIEDMONT...AS ENERGY IS SHEARED
NEWD THRU THE NRN NEW ENGLAND AND CANADIAN MARITIMES AND FLOW
ALOFT BECOMES ORIENTED MORE WESTERLY. MEAN PW FIELDS SHOW DRIER
AIR SPREADING INTO THE REGION FROM THE NW BEHIND THE FRONT AS
HIGH PRES BECOMES ESTABLISHED IN THE NORTHEAST BY EARLY NEXT
WEEK. THEREFORE EXPECT TEMPS AND POPS TO TREND LOWER DURING THE
LATER PERIODS.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
THIN LINE OF SHRA MOVING S/SE WILL LIKELY CONTINUE TO WEAKEN AS IT
APPROACHES KMDT AND KLNS. A BRIEF BIT OF CLEARING WILL DO WONDERS
TO MAKE CONDITIONS DETERIORATE OVER THE NEXT FEW HOURS. THE HIGH
MOISTURE AND LIGHT WEST WINDS WILL LIKELY LEAD TO FOG/LOW CLOUDS
FORMING OVER AT LEAST BFD AND JST. THE REST OF THE TERMINALS WILL
ALSO FOG UP THROUGH THE NIGHT...WITH LIFR FOG POSSIBLE AT MANY
LOCATIONS. SINCE HIGH PRESSURE WILL BE OVERHEAD VIS/CIG
IMPROVEMENTS WILL HAPPEN SLOWLY DURING THE MORNING - ESP WHERE
THE LOW CLOUDS RESIDE. THE LESS-CLOUDY AREAS IN THE EAST WILL
HAVE THE FOG DISSIPATE BEFORE THE LOW CLOUDS IN THE WEST BREAK UP.
THERE COULD BE SOME TALLER CU IN THE SRN TIER IN THE AFTERNOON
THANKS TO ALL THE MOISTURE. SOME LOW STRATUS MAY FORM WED NIGHT AS
THE FLOW BECOMES SOUTHERLY. A COUPLE OF SHOWERS ARE POSSIBLE THURS
AFTERNOON AS HEATING POPS BIGGER CU OFF THE HIGH TERRAIN - ESP IN
THE S/E. FOG IS EXPECTED THURSDAY MORNING AS WELL...BUT IT SHOULD
NOT BE AS WIDESPREAD AS TONIGHT.
OUTLOOK...
FRI...MAINLY VFR. CHC OF PM TSTMS WEST.
SAT...VFR/MVFR WITH SCT SHWRS/TSTMS. COLD FROPA.
SUN...AM FOG. OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/RXR
NEAR TERM...LA CORTE/RXR
SHORT TERM...FITZGERALD
LONG TERM...STEINBUGL
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
751 PM EDT TUE SEP 2 2014
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE AREA THIS EVENING. HIGH
PRESSURE WILL BUILD ALONG THE EAST COAST LATE THIS WEEK...THEN
ANOTHER COLD FRONT WILL LIKELY PUSH SOUTH ACROSS THE REGION BY
SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
SENT ANOTHER UPDATE TO BEGIN TRIMMING BACK THE WATCH AS THE LINE
MOVES INTO CENTRAL PA.
MAIN LINE OF CONVECTION EXTENDS FROM SULLIVAN COUNTY BACK TO
SOUTHERN CAMBRIA. OVERALL THE ACTIVITY SEEMS TO BE WEAKENING. IF
THIS TREND CONTINUES...WE WILL CONTINUING CANCELING COUNTIES OUT
OF THE WATCH.
BIGGER QUESTION SWITCHES TO HOW MUCH ADDITIONAL CONVECTION WE CAN
EXPECT FOR THE REMAINDER OF THE EVENING IN THE AREAS WORKED OVER
BY THE EARLIER LINE OF STORMS. LATEST HRRR SHOWS ACTIVITY DROPPING
OFF SMARTLY AFTER SUNDOWN SO I HAVE STARTED LOWERING THE EVENING
AND OVERNIGHT POPS.
DRIER AIR BEHIND THE COLD FRONT WILL REPLACE THE SULTRY LATE
SEASON HUMIDITY WE HAVE EXPERIENCED FOR THE LAST SEVERAL DAYS. IT
WILL STILL BE RATHER MILD WITH LOWS IN THE 60S. CLEARING
SKIES...A LIGHT WIND WIND AND WET GROUND WILL LIKELY LEAD TO
AREAS OF FOG LATE TONIGHT.
HIGH PRES AND ASSOC DRIER AIR MASS WILL BE OVR THE AREA
WEDNESDAY...SUPPLYING MSUNNY AND WARM CONDS. ENS MEAN 8H TEMPS NR
15C SHOULD SUPPORT MAX TEMPS FROM THE M70S NW MTNS TO THE M80S
IN THE SUSQ VALLEY.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
IT WILL CONTINUE FAIR WEDNESDAY NIGHT WITH LITTLE MORE THAN AREAS
OF LATE NIGHT FOG AS THE ONLY REAL SENSIBLE WEATHER.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
SUBTROPICAL RIDGE CENTERED OVER THE CAROLINAS WILL BE SUPPRESSED BY
SHORTWAVE ENERGY AND MODERATE-INTENSITY SFC CYCLONE TRACKING NEWD
FROM THE NRN HIGH PLAINS ACROSS WRN ONTARIO INTO NRN QUEBEC THU THRU
SAT. ITS TRAILING COLD FRONT REMAINS THE FOCUS FOR PCPN HEADING INTO
THE WEEKEND WITH CONTINUED UNCERTAINTY IN THE SEWD FRONTAL
PROGRESSION. A SLOWER TREND MAY BE EMERGING IN THE 12Z GFS/GEFS WITH
ITS FRONTAL ZONE ALIGNING CLOSER WITH THE ECMWF/GEM BY 00Z SUN. MAX
POPS SHIFT FROM NW TO SE OVER THE CWA FROM 00Z SAT TO 00Z SUN. AHEAD
OF CDFRONT...TEMPS ARE LIKELY TO PEAK ON FRIDAY WITH MEAN H85 TEMPS
+18-20C SUPPORTING WIDESPREAD HIGHS 85-90F.
THE NEXT QUESTION CONCERNS HOW QUICKLY THE FRONT CLEARS SRN PA ON
SUNDAY WITH MODEL DATA SUGGESTING THE UPPER LEVEL FRONT HANGS
BACK ALONG THE APPLCHNS/MID-ATLC PIEDMONT...AS ENERGY IS SHEARED
NEWD THRU THE NRN NEW ENGLAND AND CANADIAN MARITIMES AND FLOW
ALOFT BECOMES ORIENTED MORE WESTERLY. MEAN PW FIELDS SHOW DRIER
AIR SPREADING INTO THE REGION FROM THE NW BEHIND THE FRONT AS
HIGH PRES BECOMES ESTABLISHED IN THE NORTHEAST BY EARLY NEXT
WEEK. THEREFORE EXPECT TEMPS AND POPS TO TREND LOWER DURING THE
LATER PERIODS.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
GENERALLY VFR CONDITIONS ACROSS CENTRAL PA AT 18Z. BUT SOME
RESTRICTIONS ARE IN STORE FOR THIS AFTERNOON AND EVENING...ESP
ACROSS THE NORTH AND CENTRAL MTNS...AS A SHORTWAVE WITH INCREASING
MID LEVEL FLOW TRIGGERS A LINE OF SHOWERS/TSTMS. MOST WIDESPREAD
IMPACTS WILL BE ACROSS NORTHERN PA /GENERALLY NORTH OF I-80/ WITH
A MORE SOLID LINE OF CONVECTION LATE THIS AFTERNOON AND EARLY THIS
EVENING...THOUGH SCATTERED TSTMS ALSO POSS FURTHER SOUTH. THE
STRONGEST STORMS COULD PRODUCE DAMAGING WIND GUSTS AND SIGNIFICANT
REDUCTIONS AT AIRFIELDS AS THEY PASS THROUGH.
STORMS SHOULD CLEAR THE WESTERN HALF BY 22-24Z AND THE EAST BY
01-03Z. THEN CLEARING SKIES...A LIGHT WIND AND WET GROUND WILL
LIKELY LEAD TO AREAS OF FOG LATE TONIGHT.
OUTLOOK...
WED-THU...PATCHY AM FOG...OTHERWISE VFR.
FRI...MAINLY VFR. CHC OF PM TSTMS WEST.
SAT...VFR/MVFR WITH SCT SHWRS/TSTMS ASSOCD WITH COLD FROPA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/RXR
NEAR TERM...LA CORTE/RXR
SHORT TERM...FITZGERALD
LONG TERM...STEINBUGL
AVIATION...MARTIN/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
343 PM EDT MON SEP 1 2014
.SYNOPSIS...
WARM AND HUMID CONDITIONS WILL CONTINUE INTO TUESDAY UNTIL A COLD
FRONTAL PASSAGE BRINGS DRIER AND SLIGHTLY COOLER AIR TO CENTRAL
PENNSYLVANIA THROUGH MID WEEK. HUMIDITY WILL RETURN TOWARD THE
END OF THE WEEK AHEAD OF THE NEXT FRONTAL SYSTEM THAT WILL BRING
THE CHANCE OF RAIN FOR THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
18Z...RADAR LOOP INDICATES CONVECTIVE PCPN IS STARTING TO INCREASE
IN CVRG OVER THE LAST 30 MINUTES OVER THE SRN 1/3 OF THE CWA WHERE
THE RAP SHOWS THE HIGHEST CAPE IN PA. EVEN BETTER INSTABILITY CAN
BE FOUND SOUTH OF THE MASON DIXON LINE NEAR THE I95 CORRIDOR WHERE
THE FIRST LTG STRIKE OF THE AFTN HAS BEEN DETECTED. HIGHEST POPS
/30-40%/ HAVE BEEN PAINTED OVER THE SRN TIER ZONES THRU THE EARLY
EVENING HOURS. FURTHER TO THE NORTH...WEAK LG SCALE FORCING
COUPLED WITH MARGINAL INSTABILITY /HINDERED BY CLOUD COVER/ AND
VERY MOIST/HUMID AIRMASS CONTINUES TO SUPPORT IDEA OF MAINLY ISOLD
SHOWERS. MESO MDL GUIDANCE SHOWS EVE STORMS EVENTUALLY DISSIPATING
AFTER DARK WITH THE LOSS OF HEATING. UPSTREAM STORMS OVER THE GRT
LWR MI/OH VLY SHOULD ALSO EXHIBIT A CONSIDERABLE WEAKENING TREND
AS THE EVOLVE EWD AND MAY SURVIVE INTO WRN PA LATE TNGT.
MAIN FOCUS WILL SHIFT TO THE WEST TONIGHT AS A WELL-DEFINED COLD
FRONT APPROACHES THE AREA FROM THE N/W. HIGHEST POPS /40-50%/
WILL BE OVER THE FAR NW MTNS BASED ON MULTI-MODEL ENSEMBLE CONSENSUS
QPF. IT WILL BE MUGGY WITH LOWS 65-70F. LGT WINDS AND HI DEWPOINTS
ALONG WITH SOME PARTIAL CLEARING FAVORS SOME LOW CLOUDS/FOG.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
A RELATIVELY LOW AMPLITUDE SHORTWAVE TROUGH WILL SLIDE EWD FROM
THE GREAT LAKES/MIDWEST INTO NRN NEW ENGLAND BY THE END OF THE
PERIOD. THIS FEATURE WILL DRIVE A WELL-DEFINED COLD FRONT /WITH
SHARP MSTR-PW GRADIENT/ SEWD FROM THE LWR LKS/OH VLY ACRS THE
N-CNTRL APPALACHIANS. A CONDITIONAL RISK FOR STRONG TO ISOLATED
SEVERE STORMS WILL EXIST FROM LATE TUE MORNING THROUGH THE
AFTERNOON WITH THE PRIMARY POTNL TSTM HAZARD BEING DAMAGING
WINDS.
CLOUD COVER FROM UPSTREAM CONVECTION LKLY ONGOING AT 12Z ALONG
WITH RESIDUAL OVERNIGHT LOW STRATUS/FOG SHOULD ACT TO LIMIT
DESTABILIZATION EARLY TOMORROW. ALTHOUGH 700-500MB LAPSE RATES
WILL GENERALLY REMAIN WEAK TO POOR...THE MODELS SHOW A BELT OF
STRONGER WESTERLY MID-LVL FLOW AND DEEP LYR SHEAR. THIS SHOULD
HELP TO SUPPORT AN INCREASE IN CONVECTIVE PCPN/INTENSITY AS
RENEWED DEVELOPMENT OCCURS ALONG OUTFLOWS/DIFFERENTIAL HEATING
ZONES BY LATE MORNING INTO THE AFTERNOON...WITH SOME ORGANIZATION
INTO LINE SEGMENTS/CLUSTERS. THIS SHOULD YIELD AT LEAST AN ISOLD
DMGG WIND THREAT...WARRANTING AN UPGRADE BY SPC TO A CATEGORICAL
/SLGT/ RISK DESIGNATION. THIS HAS BEEN REFLECTED IN AN UPDATED
HWO.
EARLY CLOUDS SHOULD BREAK FOR A WARM AND HUMID DAY WITH FCST
HIGHS EXPECTED TO RANGE FROM THE MID 70S OVER THE NW TO NEAR 90
OVER THE LOWER SUSQ VLY. THE SECOND HALF OF THE PERIOD ESPECIALLY
AFTER MIDNIGHT SHOULD FEATURE A COOLER/DRYING TREND BEHIND THE
FRONT WITH PWS FALLING AOB NORMAL BY 12Z WED.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
COLD FRONT EXITING TO THE EAST TUE NIGHT ALONG WITH NORTHWEST
FLOW AROUND BUILDING HIGH PRESSURE AREA OVER OHIO VALLEY WILL
BRING A TRANSITION TO A NOTICABLY DRIER AIRMASS FOR MIDWEEK.
DAYTIME HIGHS WILL REMAIN SLIGHTLY ABOVE NORMAL...BUT LOWER
DEWPOINTS WILL MAKE IT FEEL MORE COMFORTABLE. OVERNIGHT LOWS WED
NIGHT WILL DIP TO NEAR 50F IN THE NORTHERN MTNS TO AROUND 60F IN
THE SE.
THE HIGH WILL MOVE OFF THE EAST COAST THU INTO FRI...ALLOWING MORE
HUMID AIR TO BEGIN RETURNING TO THE REGION. A SURFACE LOW SLIDES
FROM THE NORTHERN PLAINS ACROSS THE GREAT LAKES AND LIFTING INTO
S CANADA ON FRI...DRAGGING A COLD FRONT ALONG BEHIND. AS THIS
FRONT APPROACHES...AN AREA OF HIGHER PWATS /1-2"/ SURGES INTO THE
OHIO VALLEY...AND THEN INTO PA FRI NIGHT INTO SAT. AT SAME TIME A
BROAD UPPER TROUGH SAGS SOUTHWARD. THIS WILL BRING ELEVATED
CHANCES FOR SHOWERS/TSTMS STARTING FRI NIGHT IN THE NW AND
SPREADING AREAWIDE ON SAT.
BEHIND THE FRONT...AIRMASS CHANGE WILL USHER IN MUCH COOLER AND
DRIER AIR FOR LATE WEEKEND INTO EARLY NEXT WEEK. HIGHS WILL FALL
BACK ABOUT 10F...RANGING FROM THE UPPER 60S TO MID 70S. AS LARGE
HIGH PRESSURE AREA TRACKS ACROSS NEW ENGLAND...MORNING LOWS SHOULD
DIP WELL INTO THE 40S ACROSS THE NORTHERN MTNS...AND IN THE LOWER
TO MID 50S ACROSS THE SOUTH.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
18Z...CIGS/VISBYS HAVE IMPROVED TO VFR OR MVFR AS EXPECTED.
HOWEVER DESPITE A GENERAL INCREASE IN SHOWER ACTIVITY THERE IS
STILL LOW CONFIDENCE IN POINT TERMINAL IMPACTS. EVOLUTION OF
CONVECTIVE ACTIVITY AND COLLOCATION OF BEST INSTABILITY SUGGESTS
THE SRN TAFS HAVE THE BEST CHC TO SEE SCT SHOWERS OR A BRIEF TSRA
DOWNPOUR. HAVE ADDED SOME 1HR TEMPS THRU 19Z WITH SHOWERS MOVG
THRU AOO/UNV.
OTHER CONCERN WILL BE CLOUD TRENDS OVERNIGHT WITH MOIST AIRMASS
LKLY PROMOTING ANOTHER PERIOD OF LOW CIGS/FOG INTO TUE MORNING. A
COLD FRONT MOVG EWD THRU THE MIDWEST WILL ALSO BRING THE CHC FOR
SOME SHOWERS TO REACH THE NW 1/4 TO 1/3 OF THE AIRSPACE BY
EARLY TUE MORNING. THIS FRONT WILL BE A FOCUS FOR SCT-NMRS
SHWRS/TSTMS TUES AFTN-EVE AS IT MOVES SEWD ACRS CENTRAL PA. THE
RECENT GUIDANCE SUGGESTS A SLIGHTLY HIGHER PROBABILITY FOR LCL
SVR STORMS AND AT LEAST AN ISOLD THREAT FOR DAMAGING TSTM WIND
GUSTS.
OUTLOOK...
WED-THU...PATCHY AM FOG...OTHERWISE VFR.
FRI...MAINLY VFR. CHC OF PM TSTMS WEST.
SAT...VFR/MVFR WITH SCT SHWRS/TSTMS ASSOCD WITH COLD FROPA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...RXR
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
249 PM EDT MON SEP 1 2014
.SYNOPSIS...
WARM AND HUMID CONDITIONS WILL CONTINUE INTO TUESDAY UNTIL A COLD
FRONTAL PASSAGE BRINGS DRIER AND SLIGHTLY COOLER AIR TO CENTRAL
PENNSYLVANIA THROUGH MID WEEK. HUMIDITY WILL RETURN TOWARD THE
END OF THE WEEK AHEAD OF THE NEXT FRONTAL SYSTEM THAT WILL BRING
THE CHANCE OF RAIN FOR THE UPCOMING WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z...RADAR LOOP INDICATES CONVECTIVE PCPN IS STARTING TO INCREASE
IN CVRG OVER THE LAST 30 MINUTES OVER THE SRN 1/3 OF THE CWA WHERE
THE RAP SHOWS THE HIGHEST CAPE IN PA. EVEN BETTER INSTABILITY CAN
BE FOUND SOUTH OF THE MASON DIXON LINE NEAR THE I95 CORRIDOR WHERE
THE FIRST LTG STRIKE OF THE AFTN HAS BEEN DETECTED. HIGHEST POPS
/30-40%/ HAVE BEEN PAINTED OVER THE SRN TIER ZONES THRU THE EARLY
EVENING HOURS. FURTHER TO THE NORTH...WEAK LG SCALE FORCING
COUPLED WITH MARGINAL INSTABILITY /HINDERED BY CLOUD COVER/ AND
VERY MOIST/HUMID AIRMASS CONTINUES TO SUPPORT IDEA OF MAINLY ISOLD
SHOWERS. MESO MDL GUIDANCE SHOWS EVE STORMS EVENTUALLY DISSIPATING
AFTER DARK WITH THE LOSS OF HEATING. UPSTREAM STORMS OVER THE GRT
LWR MI/OH VLY SHOULD ALSO EXHIBIT A CONSIDERABLE WEAKENING TREND
AS THE EVOLVE EWD AND MAY SURVIVE INTO WRN PA LATE TNGT.
MAIN FOCUS WILL SHIFT TO THE WEST TONIGHT AS A WELL-DEFINED COLD
FRONT APPROACHES THE AREA FROM THE N/W. HIGHEST POPS /40-50%/
WILL BE OVER THE FAR NW MTNS BASED ON MULTI-MODEL ENSEMBLE CONSENSUS
QPF. IT WILL BE MUGGY WITH LOWS 65-70F. LGT WINDS AND HI DEWPOINTS
ALONG WITH SOME PARTIAL CLEARING FAVORS SOME LOW CLOUDS/FOG.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
A RELATIVELY LOW AMPLITUDE SHORTWAVE TROUGH WILL SLIDE EWD FROM
THE GREAT LAKES/MIDWEST INTO NRN NEW ENGLAND BY THE END OF THE
PERIOD. THIS FEATURE WILL DRIVE A WELL-DEFINED COLD FRONT /WITH
SHARP MSTR-PW GRADIENT/ SEWD FROM THE LWR LKS/OH VLY ACRS THE
N-CNTRL APPALACHIANS. A CONDITIONAL RISK FOR STRONG TO ISOLATED
SEVERE STORMS WILL EXIST FROM LATE TUE MORNING THROUGH THE
AFTERNOON WITH THE PRIMARY POTNL TSTM HAZARD BEING DAMAGING
WINDS.
CLOUD COVER FROM UPSTREAM CONVECTION LKLY ONGOING AT 12Z ALONG
WITH RESIDUAL OVERNIGHT LOW STRATUS/FOG SHOULD ACT TO LIMIT
DESTABILIZATION EARLY TOMORROW. ALTHOUGH 700-500MB LAPSE RATES
WILL GENERALLY REMAIN WEAK TO POOR...THE MODELS SHOW A BELT OF
STRONGER WESTERLY MID-LVL FLOW AND DEEP LYR SHEAR. THIS SHOULD
HELP TO SUPPORT AN INCREASE IN CONVECTIVE PCPN/INTENSITY AS
RENEWED DEVELOPMENT OCCURS ALONG OUTFLOWS/DIFFERENTIAL HEATING
ZONES BY LATE MORNING INTO THE AFTERNOON...WITH SOME ORGANIZATION
INTO LINE SEGMENTS/CLUSTERS. THIS SHOULD YIELD AT LEAST AN ISOLD
DMGG WIND THREAT...WARRANTING AN UPGRADE BY SPC TO A CATEGORICAL
/SLGT/ RISK DESIGNATION. THIS HAS BEEN REFLECTED IN AN UPDATED
HWO.
EARLY CLOUDS SHOULD BREAK FOR A WARM AND HUMID DAY WITH FCST
HIGHS EXPECTED TO RANGE FROM THE MID 70S OVER THE NW TO NEAR 90
OVER THE LOWER SUSQ VLY. THE SECOND HALF OF THE PERIOD ESPECIALLY
AFTER MIDNIGHT SHOULD FEATURE A COOLER/DRYING TREND BEHIND THE
FRONT WITH PWS FALLING AOB NORMAL BY 12Z WED.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL BUILD IN FOR MIDWEEK...BRINGING AT LEAST A
COUPLE OF DAYS OF MILD AND LESS HUMID WEATHER. THE HIGH SHOULD
MOVE OFF THE EAST COAST LATE IN THE WEEK ALLOWING A RETURN FLOW OF
MORE HUMID AIR INTO THE REGION...ALONG WITH THE CHANCE OF SOME
MAINLY DIURNAL CONVECTION STARTING FRIDAY.
GUIDANCE IS IN PRETTY GOOD AGREEMENT DRAGGING A COLD FRONT THROUGH
THE AREA FRIDAY NIGHT AND SATURDAY...ACCOMPANIED BY MORE SHOWERS
AND THUNDERSTORMS.
THE UPCOMING WEEK WILL BE ONE OF THE RARE EXTENDED PERIODS OF
WARMER THAN NORMAL TEMPERATURES WE HAVE SEEN THIS SUMMER. HIGH
TEMPERATURES WILL CLIMB TO ALMOST 90 ACROSS THE SOUTH AND EAST ON
TUESDAY AHEAD OF THE FRONTAL PASSAGE. THEN THE UPPER RIDGE WILL
REBOUND OVER THE EASTERN US FOR THE SECOND HALF OF THE
WEEK...KEEPING HIGH TEMPERATURES AT OR SLIGHTLY ABOVE SEASONAL
NORMALS FOR EARLY SEPTEMBER.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
18Z...CIGS/VISBYS HAVE IMPROVED TO VFR OR MVFR AS EXPECTED.
HOWEVER DESPITE A GENERAL INCREASE IN SHOWER ACTIVITY THERE IS
STILL LOW CONFIDENCE IN POINT TERMINAL IMPACTS. EVOLUTION OF
CONVECTIVE ACTIVITY AND COLLOCATION OF BEST INSTABILITY SUGGESTS
THE SRN TAFS HAVE THE BEST CHC TO SEE SCT SHOWERS OR A BRIEF TSRA
DOWNPOUR. HAVE ADDED SOME 1HR TEMPS THRU 19Z WITH SHOWERS MOVG
THRU AOO/UNV.
OTHER CONCERN WILL BE CLOUD TRENDS OVERNIGHT WITH MOIST AIRMASS
LKLY PROMOTING ANOTHER PERIOD OF LOW CIGS/FOG INTO TUE MORNING. A
COLD FRONT MOVG EWD THRU THE MIDWEST WILL ALSO BRING THE CHC FOR
SOME SHOWERS TO REACH THE NW 1/4 TO 1/3 OF THE AIRSPACE BY
EARLY TUE MORNING. THIS FRONT WILL BE A FOCUS FOR SCT-NMRS
SHWRS/TSTMS TUES AFTN-EVE AS IT MOVES SEWD ACRS CENTRAL PA. THE
RECENT GUIDANCE SUGGESTS A SLIGHTLY HIGHER PROBABILITY FOR LCL
SVR STORMS AND AT LEAST AN ISOLD THREAT FOR DAMAGING TSTM WIND
GUSTS.
OUTLOOK...
WED-THU...PATCHY AM FOG...OTHERWISE VFR.
FRI...MAINLY VFR. CHC OF PM TSTMS WEST.
SAT...VFR/MVFR WITH SCT SHWRS/TSTMS ASSOCD WITH COLD FROPA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...LA CORTE
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
108 AM CDT MON SEP 1 2014
.UPDATE...
06Z AVIATION DISCUSSION UPDATED BELOW.
&&
.SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT
POTENT SHORTWAVE EVIDENT ON WATER VAPOR OVER WYOMING. AHEAD OF
THIS WAVE...OMEGA AND UPPER JET MAX HELPING TO MAINTAIN BAND OF
RAINFALL THAT HAS TREKKED FROM SOUTH CENTRAL SD TO NORTHEAST SD
OVER THE PAST SEVERAL HOURS. HAVE BEEN ADJUSTING POPS FOR THIS
BAND OF RAIN AS IT APPEARS IT WILL SURVIVE MOST IF NOT ALL THE WAY
ACROSS THE CWA. HRRR PICKING UP ON THIS QUITE NICELY.
OVERNIGHT...EXPECTING SCATTERED SHOWERS AND STORMS TO MOVE EAST
ACROSS THE STATE BUT WITH MINIMAL SEVERE THREAT DUE TO LACK OF
INSTABILITY. ONLY QUESTION IS THE DEGREE OF AREAL COVERAGE OF
PRECIP. SOME MODELS GREATER THAN OTHERS...WITH THE HRRR
PARTICULARLY DRY AND SORT OF THE OUTLIER. MOST OTHER MODELS HAVE
ACTIVITY MOVING ACROSS AT LEAST THE SOUTHERN HALF OF SD TONIGHT.
HAVE ADJUSTED POPS ACCORDINGLY AND LINGERED THEM A BIT LONGER
THROUGH THE NIGHT AS NSSL WRF STILL SHOWS CONVECTIVE CLUSTERS OVER
SOUTHEAST SD AT 09Z TONIGHT.
A WEAKER WAVE MOVES ACROSS THE AREA MONDAY...BUT SHOULD STILL
PROVIDE FOR A FEW SCATTERED SHOWERS OR STORMS. AREAL COVERAGE DOES
NOT APPEAR IT WILL QUITE MATCH UP TO WHATS MOVING INTO WESTERN SD
RIGHT NOW...BUT WORTHY OF 20/30 POPS NONETHELESS. AGAIN A LACK OF
INSTABILITY TOMORROW SO SEVERE THREAT IS VERY LOW.
TUESDAY STILL LOOKS DRY WITH NO NOTABLE SYSTEMS IN THE AREA. 500
MB HEIGHTS RISE SLOWLY THROUGH THE DAY WITH WARM AIR ADVECTION
DEVELOPING. HIGHS WILL BUMP UP INTO THE UPPER 70S TO LOW 80S FOR
MOST AREAS.
.LONG TERM...WEDNESDAY THROUGH SUNDAY
THE EARLY PART OF THE PERIOD STARTS OFF SOMEWHAT ACTIVE AS FAIRLY
STRONG SYSTEM MOVES ACROSS THE NORTHERN PLAINS. LATEST MODELS ARE
IN FAIR AGREEMENT ON AVAILABLE MOISTURE/INSTABILITY BUT DO SUGGEST
CAPPING MIGHT FORCE MOST ACTIVITY TO REMAIN NORTH OF THE CWA
WEDNESDAY NIGHT INTO THURSDAY AS COLD FRONT MOVES EAST. THUS POPS
NO HIGHER THAN CHC NEEDED AT THIS POINT. BEHIND THE FRONT IT LOOKS
FAIRLY DRY FROM THURSDAY THROUGH SUNDAY AS HIGH PRESSURE PROVES
DOMINANT. TEMPERATURES WILL START OFF ABOVE NORMAL AT THE
BEGINNING OF THE PERIOD THEN TREND TOWARD NORMAL OR EVEN BELOW BY
THE END OF THE WEEK.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
A SHORT WAVE TROUGH MOVING EAST OF THE REGION TONIGHT WILL TAKE
THE VFR MID LEVEL CLOUDS AND SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS WITH IT. THESE MAY AFFECT ABR AND ATY.
OTHERWISE...ANOTHER SHORT WAVE TROUGH WILL DROP INTO THE REGION
FROM THE NORTHWEST LATE THIS MORNING THROUGH THIS EVENING. WITH
STEEP LAPSE RATES...SOME INSTABILITY AND MID LEVEL MOISTURE
...EXPECT MORE MID LEVEL CLOUDS ALONG WITH SCATTERED SHOWERS/STORMS
TO DEVELOP AGAIN. SOME OF THESE MAY AFFECT THE TERMINALS. INSERTED
SOME VICINITY SHOWERS IN AT ALL LOCATIONS. THESE WILL MOVE ON TO
THE EAST MONDAY EVENING.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...TMT
LONG TERM...TDK
AVIATION...MOHR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1155 PM CDT SUN AUG 31 2014
.UPDATE...FOR 06Z AVIATION.
&&
.AVIATION...06Z TAF DISCUSSION.
SKIES HAVE BEEN CLEARING OVER THE MID-STATE FOR THE LAST COUPLE OF
HOURS. THERE IS STILL A POTENTIAL FOR AN IFR CLOUD DECK TO DEVELOP
OVER THE NEXT SEVERAL HOURS ACROSS SOUTHERN PORTIONS OF THE STATE
AND SLIP NORTHWARD OVER ALL 3 TERMINALS. WHILE THERE ARE NO
INDICATIONS OF THIS WANTING TO HAPPEN IN THE CURRENT SATELLITE
IMAGERY...SOME OF THE SHORT TERM-HI RES GUIDANCE IS SUGGESTING
THIS POSSIBILITY. EVEN IF THIS DOESN`T HAPPEN...WE MAY END UP WITH
IFR TO MVFR FOG BY SUNRISE. EITHER WAY...SOME FLIGHT CATEGORY
REDUCTION IS POSSIBLE OVERNIGHT.
SOUTHERLY WINDS WILL REMAIN LIGHT UNTIL LATE MORNING AND EARLY
AFTERNOON ON LABOR DAY WHEN SOUTHWESTERLY BREEZY CONDITIONS
DEVELOP. SOME GUSTS OF 16-20 KTS WILL BE POSSIBLE UNTIL 00Z
TUESDAY.
UNGER
&&
.PREV DISCUSSION... /ISSUED 842 PM CDT SUN AUG 31 2014/
UPDATE...
AT 830 PM...RADAR RETURNS WERE MOST DEFINITELY ON A DOWNWARD
TREND. SOME SLOW MOVING CELLS DROPPED HEALTHY AMOUNTS OF RAINFALL
OVER SE WILSON COUNTY ENOUGH TO WARRANT A FLOOD ADVISORY. DID
RECEIVE A CALL MENTIONING LOW LYING AREAS BECOMING INUNDATED IN
THAT AREA. HOWEVER...COVERAGE HAS DIMINISHED AND THE MID AND UPPER
LEVEL DYNAMICS HAVE MOVED OFF EAST OF THE PLATEAU. AS A
RESULT...LOWERED POP CHANCES ACROSS THE AREA UP UNTIL MIDNIGHT AND
REMOVED SLGT CHC POPS AFTER MIDNIGHT.
IR SATELLITE AND RUC FORECAST SOUNDINGS SHOW MID LEVEL DRYING OVER
THE REST OF THE EVENING AND OVERNIGHT...LIKELY RESULTING IN MOSTLY
CLEAR SKIES AT LEAST FOR A BIT BEFORE SOME BOUNDARY LAYER MOISTURE
ADVECTS NORTHWARD OUT OF NORTHERN ALABAMA DURING THE OVERNIGHT
PERIOD. SINCE SFC MOISTURE WILL STAY IN THE UPPER 60S AND LOW 70S
AND LOW LEVEL FLOW WILL STAY SOUTHWESTERLY...LEFT PATCHY FOG
MENTION IN THE GRIDS THROUGH THE FIRST PART OF THE MORNING. BUT
WITH DECENT WIND FIELDS IN THE BOUNDARY LAYER AND AT LEAST SOME
CLOUD COVER EXPECTED TOWARDS DAYBREAK...DID NOT SEE REASON TO
INCREASE THE FOG COVERAGE TO AREAS OR DENSE WORDING.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
27
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
706 PM CDT TUE SEP 2 2014
.AVIATION...
ISOLATED THUNDERSTORMS APPEAR TO HAVE BY-PASSED KLBB WHILE
REMAINING FAR WEST OF KCDS THIS EVENING. VFR EXPECTED TO DOMINATE
OTHER THAN A RISK FOR AN IFR/MVFR CLOUD LAYER TO DEVELOP JUST
AFTER DAYBREAK WEDNESDAY AT KLBB. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 531 PM CDT TUE SEP 2 2014/
UPDATE...
THUNDERSTORMS HAVE DEVELOPED OVER THE WESTERN AND CENTRAL SOUTH
PLAINS...A BIT SOUTH OF PREVIOUS BEST-GUESS...BUT GIVE SHORT TERM
SOLUTIONS SOME CREDIT. WE HAVE UPDATED FOR LOW COVERAGE THUNDER
THROUGH EARLY THIS EVENING. 1500-2000 JOULES PER KILOGRAM OF
CONVECTIVE ENERGY BUT VERY LITTLE SHEAR CONTRIBUTING TO BRIEF
HEAVY SHOWERS AND BRIEF MOSTLY WEAK HAIL INDICATIONS AT THIS TIME.
ACTIVITY SHOULD TAKE ON BETTER NORTHERLY DRIFT...THOUGH BELIEVE
MOST ACTIVITY WILL RELENT BY DARK. RMCQUEEN
PREV DISCUSSION... /ISSUED 306 PM CDT TUE SEP 2 2014/
SHORT TERM...
FOCUS IN THE SHORT TERM IS ON SMALL CHANCE FOR ISOLATED SHOWERS
AND/OR THUNDERSTORMS LATE THIS AFTN AND THIS EVENING. RADAR IS QUIET
ATTM BUT SATELLITE SHOWING AN AREA OF CUMULUS DEVELOPMENT TO THE
EAST AND SOUTHEAST OF LUBBOCK IN AN AREA WHERE OBJECTIVE ANALYSIS
SHOWS ENHANCED INSTABILITY AND WEAKENING INHIBITION. SOME VERY
MODEST LOW LEVEL SPEED CONVERGENCE AND MOISTURE ADVECTION IN THIS
AREA MAY NOT HELP TOO MUCH BUT CERTAINLY WILL NOT HURT. A WEAK
FRONTAL BOUNDARY PULLED UP STATIONARY NEAR A MORTON TO TULIA LINE
WITH WEAK CONFLUENCE IN ITS VICINITY BUT WITH SFC DEW POINTS ABOUT 5
DEGREES LOWER THAN IN THE FORMER AREA. WOULD EXPECT THESE TWO AREAS
HAVE THE BEST CHANCE OF SEEING CONVECTIVE DEVELOPMENT. 12Z WRF-NAM
HIGHLIGHTS THE LATTER WHILE RECENT RUNS OF THE HRRR FEATURES THE
FORMER. EITHER WAY WILL LIKELY BE DIFFICULT TO GENERATE ANYTHING
OTHER THAN SMALL-SCALE AND ISOLATED SHOWERS WITH AREAL COVERAGE NOT
WARRANTING MENTION IN THE ZONE FCST ATTM.
WEDNESDAY SHOULD BE EVEN MORE DIFFICULT TO PRODUCE PRECIP WITH
STRENGTHENING HIGH PRESSURE OVERHEAD AND LOW LEVEL FLOW BECOMING
MORE UNIFORM FROM THE SOUTH. TEMPS TO REMAIN WARMER THAN NORMAL WITH
BOTH LOWS AND HIGHS NEAR WARMER MAV GUIDANCE LOOKING MORE LIKELY
ATTM.
LONG TERM...
ONLY MINOR CHANGES TO THE LONG TERM FORECAST FOR THIS ITERATION...AS
A MUTED COOLING TREND WILL BE FOLLOWED BY A POTENTIALLY WET WEEKEND
FOR PARTS OF THE REGION.
BY WEDNESDAY EVENING...A MOSTLY ZONAL UPPER FLOW REGIME WILL BE IN
PLACE ACROSS THE CONUS...WITH AN ELONGATED UPPER RIDGE IN PLACE
ACROSS MOST OF THE SOUTH...INCLUDING WEST TEXAS. WHILE THIS WILL
CONTINUE TO ENSURE MOSTLY DRY CONDITIONS THROUGH THE END OF THE WORK
WEEK...GRADUALLY DROPPING 1000-500 MB THICKNESSES WILL ALLOW
TEMPERATURES TO INCREMENTALLY FALL BACK TO A MORE REASONABLE UPPER
80S ON THE SOUTH PLAINS TO MID 90S ON THE ROLLING PLAINS.
BY LATE IN THE WEEK AND THROUGH THE WEEKEND...A BROAD UPPER TROUGH
WILL PUSH EASTWARD ACROSS THE NORTHERN CONUS...SENDING A
MODEST COLD FRONT SOUTHWARD THROUGH THE CENTRAL PLAINS AND AT LEAST
THE TEXAS PANHANDLE. MEANWHILE DEEPER MONSOONAL MOISTURE...POSSIBLY
WITH A CONNECTION TO REMNANTS OF TROPICAL STORM DOLLY...WILL BE
DRAWN NORTHWARD INTO THE SOUTHWEST AND EVENTUALLY EASTWARD AS IT
GETS CAUGHT IN THE WESTERLY UPPER FLOW ASSOCIATED WITH THE
PREVIOUSLY MENTIONED TROUGH. ALL OF THIS IS EXPECTED TO RESULT IN
INCREASING RAIN CHANCES BEGINNING AS EARLY AS LATE FRIDAY...AND
POSSIBLY LASTING THROUGH LATE SUNDAY DEPENDING ON A FEW FACTORS.
THE MOST PROMINENT OF THESE FACTORS SEEMS TO BE THE TIMING AND
STRENGTH OF THE APPROACHING COLD FRONT...AS THE GFS AND ECMWF REMAIN
ABOUT 24 HOURS APART IN THIS REGARD. THE GFS INDICATES A
SLOWER...WEAKER FRONT REACHING THE NORTHERN BORDER OF THE CWA LATE
SATURDAY AFTERNOON AND WASHING OUT ACROSS THE CWA SUNDAY.
MEANWHILE...THE ECMWF SOLUTION BRINGS THIS FRONT INTO THE AREA AS
EARLY AS LATE FRIDAY...AND PUSHES THE BOUNDARY WELL THROUGH THE CWA
BY LATE SATURDAY. THE LATTER SOLUTION NOT SURPRISINGLY DEVELOPS THE
HEAVIEST PRECIPITATION DURING THE LATE FRIDAY THROUGH SATURDAY
TIME FRAME...WHILE THE GFS SEEMS TO BE FOCUSING ON THE LATE SATURDAY
THROUGH LATE SUNDAY TIME FRAME. GIVEN THAT THE BOUNDARY WILL BE WELL
REMOVED FROM ITS PARENT TROUGH BY THE TIME IT REACHES THIS
LATITUDE...WE WILL CONTINUE TO SIDE WITH THE SLOWER GFS SOLUTION AND
HIGHLIGHT LATE SATURDAY WITH THE HIGHEST POPS. LIKEWISE...LOW END POPS
WERE ALSO EXTENDED THROUGH SUNDAY EVENING GIVEN THAT IN THIS SLOWER
SCENARIO REMNANTS OF THIS BOUNDARY AND AMPLE MOISTURE WOULD LIKELY
LINGER THROUGH THIS PERIOD. HOWEVER...UNCERTAINTIES REGARDING
FRONTAL TIMING AND STRENGTH ARE COMPOUNDED FURTHER ON SUNDAY WITH
THE POSSIBILITY OF LINGERING NOCTURNAL CONVECTION AND STABILIZING
OUTFLOWS.
BY MONDAY...THE UPPER RIDGE IS EXPECTED TO SLIGHTLY AMPLIFY ACROSS
THE SOUTHERN PLAINS WHILE THE COLUMN DRIES CONSIDERABLY. THIS
SHOULD TAPER OFF PRECIPITATION CHANCES UNTIL LATER IN THE WEEK WHEN
ANOTHER POSSIBLY STRONGER COLD FRONT MOVES THROUGH THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 61 92 62 90 62 / 10 0 10 10 10
TULIA 68 93 66 91 66 / 20 0 10 0 10
PLAINVIEW 68 93 66 90 66 / 20 0 0 0 10
LEVELLAND 66 92 66 90 67 / 20 0 10 10 0
LUBBOCK 72 93 68 92 67 / 20 0 0 10 0
DENVER CITY 66 91 66 89 66 / 20 0 10 10 10
BROWNFIELD 68 93 67 90 67 / 20 0 0 10 0
CHILDRESS 75 97 75 96 72 / 10 0 0 0 0
SPUR 73 97 72 94 71 / 10 0 0 10 10
ASPERMONT 76 99 74 96 73 / 0 0 0 10 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/05
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
141 AM EDT MON SEP 1 2014
.SYNOPSIS...
THE REGION WILL STAY BETWEEN A LARGE HIGH PRESSURE SYSTEM OVER
THE SOUTHEAST UNITED STATES AND A COMPLEX LOW PRESSURE SYSTEM
CROSSING THE GREAT LAKES. DISTURBANCES PASSING BETWEEN THESE TWO
FEATURES WILL COMBINE WITH HEAT AND HUMIDITY TO RESULT IN
PERIODIC CHANCES OF SHOWERS AND STORMS INTO EARLY WEEK. A COLD
FRONT FINALLY ARRIVES FROM THE NORTH WEDNESDAY INTO THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 102 AM EDT MONDAY...
MADE SOME MINOR ADJUSTMENTS IN POPS AND TEMPERATURES FOR THIS
MORNING. SHAPED POPS THIS MORNING TOWARDS A BLEND OF RAP AND HRRR.
MORE CHANGES LATER THIS MORNING.
AS OF 920 PM EDT SUNDAY...
MAIN AXIS OF MOISTURE CONVERGENCE LIES FROM MD-CENTRAL WV. MAIN
UPPER IMPULSE THAT WAS OVER TN EARLIER HAS WEAKENED AS HAVE THE
SHOWERS UPSTREAM. OVERNIGHT NOT REALLY SEEING MUCH AS AIRMASS
STABILIZES. WILL KEEP THE HIGHER POPS OVER THE WV MTNS INTO FAR SW
VA...AS ANOTHER WEAK IMPULSE EDGES CLOSER TO THE MTNS BY DAWN.
OTHERWISE EXPECT MID DECK OF CLOUDS TO REMAIN IN THE WESTERN HALF
OF THE CWA WHILE THE EAST CLEARS SOME TOWARD MORNING. OVERALL FOG
THREAT IS PATCHY BUT COULD GET DENSE OUT EAST IF IT CLEARS OUT
ENOUGH. NO OTHER MAJOR CHANGES TO THE FORECAST THROUGH DAWN.
PREVIOUS VALID DISCUSSION...
SHORTWAVES WILL BE EXITING BY EARLY MONDAY LEAVING THE REGION IN DECENT
WEST/SW FLOW ALOFT BUT WITHOUT MUCH FORCING WELL IN ADVANCE OF THE NEXT
UPSTREAM 5H TROF/COLD FRONT TO THE NW. FORECAST SOUNDINGS SHOW QUITE A
DEEP WESTERLY FLOW WHICH RESULTS IN DRYING ALOFT/LOWERING PWATS ESPCLY
WEST MONDAY AFTERNOON AND A LEE TROUGH ACROSS THE PIEDMONT. MOST
GUIDANCE SOLUTIONS SHOW A LACK OF MUCH CONVECTION IN THIS REGIME WITH
ANY FOCUS PROVIDED BY OROGRAPHICS DUE TO WESTERLY CONVERGENCE AND
PERHAPS LATE DAY LOW LEVEL BACKING SE. THUS WILL LEAVE IN SOME LOW POPS
MAINLY WEST AS APPEARS A SUBTLE WAVE ALOFT COULD SNEAK THROUGH AROUND
THE TIME OF MAX HEATING. OTRW EXPECT WEAK LAPSES...LACK OF DEEP
INSTABILITY AND EASTERN DOWNSLOPE TO LIMIT OVERALL COVERAGE WITH MUCH
OF THE DAY LIKELY DRY AFTER EARLY MID DECK/FOG ERODE.
COULD BE ONE OF THE WARMEST DAYS SEEN IN A WHILE WITH 85H TEMPS PUSHING
+21C OVER DECENT DOWNSLOPE AND UNDER AMPLE AFTERNOON SUN. THIS WOULD
SUPPORT SOME MID 90S PIEDMONT...WITH UPPER 80S/LOW 90S BLUE RIDGE...
AND LOW/MID 80S WESTERN ELEVATIONS IF CAN GET A TEMP JUMP AFTER A WARM
START IN THE MORNING.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 230 PM EDT SUNDAY...
WITH WEAK HIGH PRESSURE BUILDING IN FROM THE SOUTH...EXPECT TO HEAD
INTO LATE MONDAY NIGHT WITH MOSTLY CLEAR SKIES AND LIGHT WINDS. AS
SUCH...WOULD NOT BE SURPRISED TO SEE PATCHY FOG DEVELOP IN SOME OF
THE MOUNTAIN VALLEYS EARLY MORNING...WHICH WILL BURN OFF QUICKLY
SHORTLY AFTER 9 AM.
DURING TUESDAY AFTERNOON...SHOWER AND THUNDERSTORM ACTIVITY WILL
INCREASE AS AN UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT APPROACH
FROM THE WEST. ACTIVITY WILL START OFF ACROSS THE MOUNTAINS...SPOTTY
AT FIRST DUE TO THE WESTERLY DOWNSLOPE FLOW...AND THEN WILL SPREAD
EAST ACROSS THE PIEDMONT DURING THE EVENING AS THE UPPER LEVEL
ENERGY SHIFTS EAST. LIGHT WINDS AND WARM TEMPERATURES ALOFT WILL
LIMIT INSTABILITY...AND BELIEVE STRONG THUNDERSTORMS WILL BE
ISOLATED AND SHORT LIVED. SHOWER AND THUNDERSTORM ACTIVITY WILL THEN
DIMINISH THROUGH THE NIGHT WITH THE LOSS OF HEATING.
BY WEDNESDAY MORNING...WILL HAVE A WEAK BOUNDARY SITUATED ACROSS OUR
AREA...WHICH WILL EXHIBIT LITTLE MORE THAN A SHIFT IN WIND DIRECTION
FROM ONE SIDE TO THE OTHER AS THE TRULY COOLER AND DRIER AIR WILL
REMAIN WELL NORTH OF OUR AREA. REGARDLESS...THE LOW LEVEL
CONVERGENCE ALONG THE BOUNDARY WILL BE ENOUGH TO TRIGGER ANOTHER
ROUND OF SPOTTY SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON AND
EVENING. BETTER CHANCES FOR RAINFALL WILL BE FOUND SOUTH OF HIGHWAY
460.
TEMPERATURES HEADING INTO THE MIDDLE OF THE WEEK WILL BE WARMER THAN
NORMAL THANKS TO UPPER LEVEL RIDGING ACROSS THE SOUTHEAST STATES.
LOOK FOR HIGHS TO RANGE FROM THE LOW/MID 80S ACROSS THE MOUNTAINS...
TO THE LOW/MID 90S ACROSS THE SOUTHSIDE. OVERNIGHT LOWS WILL RANGE
FROM THE MID 60S WEST TO THE LOW 70S EAST.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 345 PM SUNDAY...
A WEAK BOUNDARY WILL REMAIN SITUATED ACROSS THE AREA ON
THURSDAY... PROVIDING THE LOW LEVEL FOCUS FOR SHOWERS AND
THUNDERSTORMS... MAINLY SOUTH OF HIGHWAY 460. ACTIVITY IS EXPECTED
TO REMAIN WIDELY SCATTERED DUE TO THE UPPER LEVEL RIDGE ACROSS THE
SOUTHEAST STATES BUILDING NORTH...HELPING TO LIMIT INSTABILITY.
HIGH PRESSURE WILL PASS ACROSS NEW ENGLAND...ALLOWING WINDS TO
SHIFT EASTERLY THROUGH THE DAY...AND THEN SOUTHEASTERLY DURING THE
EVENING.
AN APPROACHING UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT WILL
TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE REGION ON
FRIDAY AND SATURDAY. THE COLD FRONT WILL MOVE ACROSS OUR AREA
SATURDAY NIGHT...USHERING IN COOLER AND DRIER CANADIAN HIGH
PRESSURE.
TROPICAL AIR WILL REMAIN ACROSS THE AREA THROUGH THE END OF THE
WEEK. AS SUCH...EXPECT WARM AND MUGGY CONDITIONS...WITH
TEMPERATURES HOLDING SLIGHTLY ABOVE NORMAL. COOLER TEMPERATURES
WILL ARRIVE WITH THE COLD FRONT AT THE END OF THE WEEK.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 127 AM EDT MONDAY...
A SHORTWAVE WILL LIFT NORTHEAST THIS MORNING ACROSS THE REGION.
A FEW SHOWERS WILL MOVE EAST ACROSS THE REGION THIS MORNING.
THE BEST CHANCE OF A SHOWER WILL OCCUR AT BLF AND LWB. IN THE
WAKE OF THE SHORTWAVE...THE OVERALL THREAT OF SHOWERS WILL FADE
WITH A SCT/BKN MID DECK LINGERING.
PATCHY FOG MAY DEVELOP THIS MORNING...BUT THE MID DECK SHOULD
LIMIT HOW FAR DOWN VSBYS DROP. WILL KEEP MOST TAF SITES NO WORSE
THAN MVFR THIS MORNING WITH LWB DROPPING OCCASIONALLY TO IFR
AFTER 10Z.
AHEAD OF THE UPSTREAM COLD FRONT...DEEP WESTERLY FLOW COMBINED
WITH LACK OF FOCUS AND DECENT MIXING SHOULD INHIBIT MUCH
CONVECTION TODAY ESPECIALLY IF EARLY MID DECK PERSISTS. THIS
SUPPORTS GOOD FLYING CONDITIONS FOR MUCH OF LABOR DAY AFTER EARLY
LOW CLOUDS/FOG FADE WITH ONLY ISOLATED CONVECTION LIKELY.
MEDIUM CONFIDENCE ON CEILINGS...VISIBILITIES AND WINDS DURING THE
TAF PERIOD.
EXTENDED DISCUSSION...
UPPER TROUGH AND ITS ASSOCIATED COLD FRONT WILL APPROACH FROM THE
NORTHWEST TUESDAY WITH SIMILAR ISOLATED SHOWERS/STORMS EXPECTED
DURING THE DAY AHEAD OF THE BOUNDARY. FRONT SETTLES CLOSER TUESDAY
NIGHT INTO WEDNESDAY...WHEN BETTER COVERAGE OF SHRA/TSRA IS
EXPECTED...AND THEN ACROSS THE SOUTH THURSDAY WHERE THE BOUNDARY
STALLS. HOWEVER LOW CONFIDENCE ON THE TIMING AND SOUTHWARD
POSITION OF THE BOUNDARY AT THIS POINT. THUS APPEARS MAINLY VFR
ON TUESDAY...WITH PERIODS OF MVFR WEDNESDAY-THURSDAY IN MORE
ORGANIZED MAINLY AFTERNOON/EVENING CONVECTION...AND MVFR/IFR UNDER
EARLY MORNING FOG IN THE VALLEYS AND WHERE EARLIER HEAVY RAIN
OCCURRED. FRONT WASHES OUT TO THE SOUTH OF THE AREA FRIDAY WITH
MORE DIURNAL NATURE SHOWERS AND STORMS...OTRW VFR.
&&
.EQUIPMENT...
AS OF 730 AM EDT FRIDAY ...
THE VISIBILITY SENSOR AT KDAN...DANVILLE REGIONAL AIRPORT...WILL
BE OUT OF SERVICE UNTIL FURTHER NOTICE. A PART HAS BEEN BACK-ORDERED.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/JH
NEAR TERM...JH/KK/WP
SHORT TERM...NF
LONG TERM...NF
AVIATION...JH/KK/WP
EQUIPMENT...AMS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
102 AM EDT MON SEP 1 2014
.SYNOPSIS...
THE REGION WILL STAY BETWEEN A LARGE HIGH PRESSURE SYSTEM OVER
THE SOUTHEAST UNITED STATES AND A COMPLEX LOW PRESSURE SYSTEM
CROSSING THE GREAT LAKES. DISTURBANCES PASSING BETWEEN THESE TWO
FEATURES WILL COMBINE WITH HEAT AND HUMIDITY TO RESULT IN
PERIODIC CHANCES OF SHOWERS AND STORMS INTO EARLY WEEK. A COLD
FRONT FINALLY ARRIVES FROM THE NORTH WEDNESDAY INTO THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 102 AM EDT MONDAY...
MADE SOME MINOR ADJUSTMENTS IN POPS AND TEMPERATURES FOR THIS
MORNING. SHAPED POPS THIS MORNING TOWARDS A BLEND OF RAP AND HRRR.
MORE CHANGES LATER THIS MORNING.
AS OF 920 PM EDT SUNDAY...
MAIN AXIS OF MOISTURE CONVERGENCE LIES FROM MD-CENTRAL WV. MAIN
UPPER IMPULSE THAT WAS OVER TN EARLIER HAS WEAKENED AS HAVE THE
SHOWERS UPSTREAM. OVERNIGHT NOT REALLY SEEING MUCH AS AIRMASS
STABILIZES. WILL KEEP THE HIGHER POPS OVER THE WV MTNS INTO FAR SW
VA...AS ANOTHER WEAK IMPULSE EDGES CLOSER TO THE MTNS BY DAWN.
OTHERWISE EXPECT MID DECK OF CLOUDS TO REMAIN IN THE WESTERN HALF
OF THE CWA WHILE THE EAST CLEARS SOME TOWARD MORNING. OVERALL FOG
THREAT IS PATCHY BUT COULD GET DENSE OUT EAST IF IT CLEARS OUT
ENOUGH. NO OTHER MAJOR CHANGES TO THE FORECAST THROUGH DAWN.
PREVIOUS VALID DISCUSSION...
SHORTWAVES WILL BE EXITING BY EARLY MONDAY LEAVING THE REGION IN DECENT
WEST/SW FLOW ALOFT BUT WITHOUT MUCH FORCING WELL IN ADVANCE OF THE NEXT
UPSTREAM 5H TROF/COLD FRONT TO THE NW. FORECAST SOUNDINGS SHOW QUITE A
DEEP WESTERLY FLOW WHICH RESULTS IN DRYING ALOFT/LOWERING PWATS ESPCLY
WEST MONDAY AFTERNOON AND A LEE TROUGH ACROSS THE PIEDMONT. MOST
GUIDANCE SOLUTIONS SHOW A LACK OF MUCH CONVECTION IN THIS REGIME WITH
ANY FOCUS PROVIDED BY OROGRAPHICS DUE TO WESTERLY CONVERGENCE AND
PERHAPS LATE DAY LOW LEVEL BACKING SE. THUS WILL LEAVE IN SOME LOW POPS
MAINLY WEST AS APPEARS A SUBTLE WAVE ALOFT COULD SNEAK THROUGH AROUND
THE TIME OF MAX HEATING. OTRW EXPECT WEAK LAPSES...LACK OF DEEP
INSTABILITY AND EASTERN DOWNSLOPE TO LIMIT OVERALL COVERAGE WITH MUCH
OF THE DAY LIKELY DRY AFTER EARLY MID DECK/FOG ERODE.
COULD BE ONE OF THE WARMEST DAYS SEEN IN A WHILE WITH 85H TEMPS PUSHING
+21C OVER DECENT DOWNSLOPE AND UNDER AMPLE AFTERNOON SUN. THIS WOULD
SUPPORT SOME MID 90S PIEDMONT...WITH UPPER 80S/LOW 90S BLUE RIDGE...
AND LOW/MID 80S WESTERN ELEVATIONS IF CAN GET A TEMP JUMP AFTER A WARM
START IN THE MORNING.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 230 PM EDT SUNDAY...
WITH WEAK HIGH PRESSURE BUILDING IN FROM THE SOUTH...EXPECT TO HEAD
INTO LATE MONDAY NIGHT WITH MOSTLY CLEAR SKIES AND LIGHT WINDS. AS
SUCH...WOULD NOT BE SURPRISED TO SEE PATCHY FOG DEVELOP IN SOME OF
THE MOUNTAIN VALLEYS EARLY MORNING...WHICH WILL BURN OFF QUICKLY
SHORTLY AFTER 9 AM.
DURING TUESDAY AFTERNOON...SHOWER AND THUNDERSTORM ACTIVITY WILL
INCREASE AS AN UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT APPROACH
FROM THE WEST. ACTIVITY WILL START OFF ACROSS THE MOUNTAINS...SPOTTY
AT FIRST DUE TO THE WESTERLY DOWNSLOPE FLOW...AND THEN WILL SPREAD
EAST ACROSS THE PIEDMONT DURING THE EVENING AS THE UPPER LEVEL
ENERGY SHIFTS EAST. LIGHT WINDS AND WARM TEMPERATURES ALOFT WILL
LIMIT INSTABILITY...AND BELIEVE STRONG THUNDERSTORMS WILL BE
ISOLATED AND SHORT LIVED. SHOWER AND THUNDERSTORM ACTIVITY WILL THEN
DIMINISH THROUGH THE NIGHT WITH THE LOSS OF HEATING.
BY WEDNESDAY MORNING...WILL HAVE A WEAK BOUNDARY SITUATED ACROSS OUR
AREA...WHICH WILL EXHIBIT LITTLE MORE THAN A SHIFT IN WIND DIRECTION
FROM ONE SIDE TO THE OTHER AS THE TRULY COOLER AND DRIER AIR WILL
REMAIN WELL NORTH OF OUR AREA. REGARDLESS...THE LOW LEVEL
CONVERGENCE ALONG THE BOUNDARY WILL BE ENOUGH TO TRIGGER ANOTHER
ROUND OF SPOTTY SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON AND
EVENING. BETTER CHANCES FOR RAINFALL WILL BE FOUND SOUTH OF HIGHWAY
460.
TEMPERATURES HEADING INTO THE MIDDLE OF THE WEEK WILL BE WARMER THAN
NORMAL THANKS TO UPPER LEVEL RIDGING ACROSS THE SOUTHEAST STATES.
LOOK FOR HIGHS TO RANGE FROM THE LOW/MID 80S ACROSS THE MOUNTAINS...
TO THE LOW/MID 90S ACROSS THE SOUTHSIDE. OVERNIGHT LOWS WILL RANGE
FROM THE MID 60S WEST TO THE LOW 70S EAST.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 345 PM SUNDAY...
A WEAK BOUNDARY WILL REMAIN SITUATED ACROSS THE AREA ON
THURSDAY... PROVIDING THE LOW LEVEL FOCUS FOR SHOWERS AND
THUNDERSTORMS... MAINLY SOUTH OF HIGHWAY 460. ACTIVITY IS EXPECTED
TO REMAIN WIDELY SCATTERED DUE TO THE UPPER LEVEL RIDGE ACROSS THE
SOUTHEAST STATES BUILDING NORTH...HELPING TO LIMIT INSTABILITY.
HIGH PRESSURE WILL PASS ACROSS NEW ENGLAND...ALLOWING WINDS TO
SHIFT EASTERLY THROUGH THE DAY...AND THEN SOUTHEASTERLY DURING THE
EVENING.
AN APPROACHING UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT WILL
TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE REGION ON
FRIDAY AND SATURDAY. THE COLD FRONT WILL MOVE ACROSS OUR AREA
SATURDAY NIGHT...USHERING IN COOLER AND DRIER CANADIAN HIGH
PRESSURE.
TROPICAL AIR WILL REMAIN ACROSS THE AREA THROUGH THE END OF THE
WEEK. AS SUCH...EXPECT WARM AND MUGGY CONDITIONS...WITH
TEMPERATURES HOLDING SLIGHTLY ABOVE NORMAL. COOLER TEMPERATURES
WILL ARRIVE WITH THE COLD FRONT AT THE END OF THE WEEK.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 725 PM EDT SUNDAY...
TOOK SHOWERS OUT OF THE LWB TAF THIS EVENING. STILL CANNOT RULE
OUT A SHOWER INVOF BLF/LWB OVERNIGHT BUT THE CHANCES ARE LIMITED.
OTHERWISE...OVERNIGHT THE OVERALL THREAT OF SHOWERS WILL FADE WITH
A SCT/BKN MID DECK LINGERING. FOG CHANCES ARE GOOD BUT THE MID
DECK SHOULD LIMIT HOW FAR DOWN VSBYS DROP. WILL KEEP MOST TAF
SITES NO WORSE THAN MVFR OVERNIGHT WITH LWB DROPPING OCCASIONALLY
TO IFR AFTER 10Z.
LAST MID LEVEL WAVE WILL PASS TO THE NW BY EARLY MONDAY LEAVING
THE AREA IN BETWEEN THIS FEATURE AND THE NEXT UPSTREAM COLD FRONT.
DEEP WESTERLY FLOW COMBINED WITH LACK OF FOCUS AND DECENT MIXING
SHOULD INHIBIT MUCH CONVECTION DURING MONDAY ESPCLY IF EARLY MID
DECK PERSISTS. THIS SUPPORTS GOOD FLYING CONDITIONS FOR MUCH OF
MONDAY AFTER EARLY LOW CLOUDS/FOG FADE WITH ONLY ISOLATED
CONVECTION LIKELY.
EXTENDED DISCUSSION...
UPPER TROUGH AND ITS ASSOCIATED COLD FRONT WILL APPROACH FROM THE
NORTHWEST TUESDAY WITH SIMILAR ISOLATED SHOWERS/STORMS EXPECTED
DURING THE DAY AHEAD OF THE BOUNDARY. FRONT SETTLES CLOSER TUESDAY
NIGHT INTO WEDNESDAY...WHEN BETTER COVERAGE OF SHRA/TSRA IS
EXPECTED...AND THEN ACROSS THE SOUTH THURSDAY WHERE THE BOUNDARY
STALLS. HOWEVER LOW CONFIDENCE ON THE TIMING AND SOUTHWARD
POSITION OF THE BOUNDARY AT THIS POINT. THUS APPEARS MAINLY VFR
ON TUESDAY...WITH PERIODS OF MVFR WEDNESDAY-THURSDAY IN MORE
ORGANIZED MAINLY AFTERNOON/EVENING CONVECTION...AND MVFR/IFR UNDER
EARLY MORNING FOG IN THE VALLEYS AND WHERE EARLIER HEAVY RAIN
OCCURRED. FRONT WASHES OUT TO THE SOUTH OF THE AREA FRIDAY WITH
MORE DIURNAL NATURE SHOWERS AND STORMS...OTRW VFR.
&&
.EQUIPMENT...
AS OF 730 AM EDT FRIDAY ...
THE VISIBILITY SENSOR AT KDAN...DANVILLE REGIONAL AIRPORT...WILL
BE OUT OF SERVICE UNTIL FURTHER NOTICE. A PART HAS BEEN BACK-ORDERED.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/JH
NEAR TERM...JH/KK/WP
SHORT TERM...NF
LONG TERM...NF
AVIATION...AMS/JH/WP
EQUIPMENT...AMS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1239 PM CDT MON SEP 1 2014
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 308 AM CDT MON SEP 1 2014
WATER VAPOR SATELLITE LOOP COUPLED WITH RAP ANALYSIS SHOWS VIGOROUS
MID-LEVEL TROUGH ROTATING THROUGH THE PLAINS TOWARD THE UPPER
MISSISSIPPI RIVER VALLEY. AT THE SURFACE 999MB LOWS WAS OVER WESTERN
ONTARIO WITH A COLD FRONT EXTENDING SOUTHWARD THROUGH MN/NW
IA/CENTRAL NEB. RADAR WAS LIT UP WITH SHOWERS/THUNDERSTORMS ACROSS
EASTERN MN INTO THE FORECAST AREA AHEAD OF THE MID-LEVEL WAVE AND
SURFACE COLD FRONT. OTHERWISE...TEMPERATURES ACROSS THE AREA EARLY
THIS MORNING WERE IN THE 60S.
LOOK FOR THE SURFACE COLD FRONT AND ASSOCIATED CONVECTION TO
CONTINUE PUSHING EAST ACROSS THE AREA THIS MORNING WITH THE BULK OF
THE RAIN EXITING EAST BY LATE MORNING. KEPT LINGERING AND
DIMINISHING CHANCES GOING HOWEVER INTO THE AFTERNOON AS THE MID-
LEVEL TROUGH/COLD AIR ALOFT POSSIBLY POPPING A FEW INSTABILITY
SHOWERS AND THUNDERSTORMS. NOT EXPECTING ANY SEVERE THREAT AS BEST
CAPE AND WIND SHEAR SHIFT EAST/SOUTHEAST OF THE AREA.
FOR TONIGHT...WILL SEE ANOTHER WEAK MID-LEVEL WAVE ROTATE TOWARD THE
AREA FROM THE NORTHERN PLAINS. NAM SHOWING A DECENT SHOT OF 700-
300MB PVA MOVING IN MAINLY WEST OF THE MISSISSIPPI RIVER AFTER
MIDNIGHT WITH BUFKIT SHOWING INSTABILITY/MOISTURE MAINLY CONFINED
ABOVE 800MB. KEPT A SMALL-END CHANCE OF SHOWERS/ISOLATED WEST OF THE
MISSISSIPPI AFTER MIDNIGHT BASED ON THIS SIGNAL. OVERNIGHT LOWS ARE
EXPECTED TO FALL INTO THE 50S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 308 AM CDT MON SEP 1 2014
A SMALL CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO
TUESDAY MAINLY NORTH OF I-94 AS THE WEAK MID-LEVEL TROUGH ROTATES
ACROSS THE FORECAST AREA. PLAN ON HIGHS RANGING FROM THE MIDDLE 70S
ACROSS NORTH CENTRAL WI...TO THE UPPER 70S/LOWER 80S ELSEWHERE.
SURFACE CYCLOGENESIS OVER THE NORTHERN PLAINS WILL PUSH A WARM FRONT
TOWARD THE AREA WEDNESDAY/WEDNESDAY NIGHT. ALL MODELS SHOW
INCREASING 850MB MOISTURE TRANSPORT/WARM AIR ADVECTION NOSING INTO
THE AREA WITH THE FRONT FOR INCREASING COVERAGE OF THUNDERSTORMS.
PRECIPITABLE WATER VALUES PUSHING 1.9 INCHES BY THURSDAY MORNING WITH
WARM CLOUD DEPTH LAYERS INCREASING INTO THE 4-4.5KM RANGE. BASED ON
THIS SIGNAL...WILL HAVE TO WATCH FOR A HEAVY RAINFALL POTENTIAL
ALONG WITH OTHER SEVERE THREATS AS WELL AS CAPE AND BULK SHEAR
INCREASE ALONG THE WARM FRONT. AT THIS POINT...MODELS SHOWING HIGHER
SEVERE POTENTIAL STAYING WEST OF THE MISSISSIPPI RIVER IN MORE
FAVORABLE CAPE/SHEAR ENVIRONMENT. WILL HAVE TO KEEP A CLOSE ON THIS
OVER THE NEXT COUPLE DAYS. LOOK FOR HIGHS ON WEDNESDAY TO TOP OFF IN
THE UPPER 70S TO MIDDLE 80S WITH DEW POINTS CREEPING UP INTO THE 65-
70 DEGREE RANGE.
THUNDERSTORM CHANCES CONTINUE THURSDAY INTO THURSDAY NIGHT AS THE
LOW PULLS NORTHEAST INTO ONTARIO CANADA...PUSHING A COLD FRONT
THROUGH THE AREA. THURSDAY WILL HAVE TO BE WATCHED CLOSELY AS WELL
FOR SEVERE POTENTIAL AS THE GFS IS SHOWING 0-6KM BULK SHEAR OF 30-
50KT COUPLED WITH MUCAPE POOL OF 2500-4500J/KG. HIGHS ON THURSDAY
AHEAD OF THE COLD FRONT ARE EXPECTED TO TOP OFF WELL INTO THE 80S
WITH DEW POINTS IN THE 70-75 DEGREE RANGE.
DRIER/COOLER AIR FILTERS INTO THE AREA FRIDAY AND INTO THE WEEKEND
AS CANADIAN HIGH PRESSURE BUILD INTO THE REGION. PLAN ON
TEMPERATURES BY THIS WEEKEND TO FEEL A BIT MORE LIKE FALL WITH HIGHS
IN THE 60S/LOWER 70S AND LOWS IN THE 50S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1239 PM CDT MON SEP 1 2014
MAIN AVIATION FORECAST CONCERNS IS FOG POTENTIAL IN THE MISSISSIPPI
RIVER VALLEY TONIGHT. LATEST KARX RADAR INDICATES LAST LINE OF
SHOWERS ALONG SURFACE COLD FRONT EXTENDING FROM WESTERN WISCONSIN
INTO NORTHEAST IOWA PER LATEST 17Z SURFACE ANALYSIS. LATEST 17Z
METARS ARE INDICATING CEILING HEIGHTS RISING ABOVE MVFR CONDITIONS
AND BECOMING VFR CONDITIONS AT TAF SITES THIS AFTERNOON. WEAK
SURFACE RIDGE BUILDS INTO NORTHERN IOWA BEHIND COLD FRONT AND ALLOWS
SKIES TO CLEAR WEST TO EAST ACROSS THE AREA THIS AFTERNOON INTO THIS
EVENING. THE 02.12Z NAM BUFKIT SOUNDING SHOWS INVERSION DEVELOPING
AT LSE TAF SITE AND WINDS BECOME LIGHT WITHIN THE LOWEST 500
FEET...HOWEVER BUFKIT SOUNDING SHOW 15 KNOTS JUST ABOVE 500 FEET
PLUS A WEAK IMPULSE PRODUCES A MID LEVEL CLOUD DECK OVER THE REGION.
THIS WOULD INHIBIT ANY FOG DEVELOPMENT IN THE MISSISSIPPI RIVER
VALLEY AND AT LSE TAF SITE. AT THIS TIME...DID NOT INTRODUCE ANY
FOG AT LSE TAF SITE AND LATER SHIFTS WILL HAVE TO MONITOR IF SKIES
REMAIN CLEAR THROUGH THE NIGHT TIME HOURS. VFR CONDITIONS WILL
PREVAIL AT RST TAF SITE THROUGH MUCH OF THE PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...DTJ
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1050 AM CDT MON SEP 1 2014
.AVIATION/18Z TAFS/...LOW PRESSURE LIFTING NORTHEAST FROM LAKE
SUPERIOR WITH TRAILING COLD FRONT INTO NW WI THROUGH CNTRL IA.
AIRMASS QUITE STABLE ATTM AHEAD OF THIS FRONT WITH JUST A COUPLE
BATCHES OF SHRA. CLOUD COVER IS EXTENSIVE AND PRIMARY
SHORTWAVE/SPEED MAX LIFTING NORTHEAST. EXTENSIVE CLOUD COVER
UPSTREAM LIKELY TO KEEP INSTABILITY FROM GETTING OUT OF
HAND....THOUGH SOME HERE AND THERE. SO WHILE FRONT IS YET TO WORK
THROUGH...SVR CONVECTIVE DEVELOPMENT NOT LIKELY. MESO MODELS
CONTINUE TO PULL BACK ON STORM STRENGTH THIS AFTN/EVE...SO AGREE
WITH SPC/S REMOVAL OF SLGT RISK FROM SRN WI. EXPECT MVFR CIGS TO
LINGER INTO THE AFTERNOON WITH THE VERY MOIST LOW LEVELS AHEAD OF
THE COLD FRONT. SOME IMPROVEMENT OF THESE CIGS INTO THIS EVENING
ONCE SFC COLD FRONT WORKS THROUGH AND DRIER NW WINDS KICK IN.
WEAK HIGH BUILDS IN TNGT WITH SFC TROUGH POSSIBLY GENERATING A FEW
SHRA TUE AFTN.
PC
&&
.PREV DISCUSSION... /ISSUED 355 AM CDT MON SEP 1 2014/
TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.
AREA OF RAIN SHOWERS AND A FEW THUNDERSTORMS OVER SOUTHWEST
WISCONSIN...INTO FAR EASTERN IOWA AND FAR NORTHWEST ILLINOIS...HAS
BEEN SLOWLY WEAKENING OVER THE PAST FEW HOURS. THIS WAS BEING DRIVEN
BY 500 MB VORTICITY MAXIMUM MOVING INTO THE AREA...UPPER DIVERGENCE
WITH RIGHT REAR QUADRANT OF 250 MB JET STREAK...ALONG WITH 850 MB
LOW LEVEL JET. SPC MESOANALYSIS PAGE SHOWING A GOOD AMOUNT OF
CONVECTIVE INHIBITION OVER THE AREA...WHICH MAY BE HELPING WEAKEN
CONVECTION.
STILL...THE ABOVE MAIN FEATURES SHOULD CONTINUE TO BRING SOME
SHOWERS ACROSS THE AREA THROUGH THE MIDDLE MORNING HOURS. THIS IS
SUPPORTED BY THE HRRR AND OTHER MESOSCALE MODELS...THOUGH THEY AREA
SOMEWHAT OVERDONE WITH CURRENT PRECIPITATION TRENDS. THUS...WILL
CONTINUE HIGH POPS THROUGH THE MIDDLE MORNING HOURS FOR SHOWERS AND
ISOLATED STORMS.
MAIN ISSUE WILL BE CONVECTIVE TRENDS THIS AFTERNOON AND EVENING WITH
PASSING COLD FRONT AND SEVERE WEATHER POSSIBILITIES. COLD FRONT WILL
PASS EAST THROUGH THE AREA THIS AFTERNOON...EXITING THE SOUTHEAST BY
MIDDLE TO LATE EVENING. SYNOPTIC MODELS VARY A BIT IN THE TIMING OF
THE FRONT. FRONTOGENESIS RESPONSE WITH FRONT IS WEAK AS IT MOVES
THROUGH THE AREA...THOUGH ELONGATED 500 MB VORTICITY MAXIMUM PUSHES
INTO THE AREA FROM THE WEST. WENT WITH CHANCE POPS FOR THIS
AFTERNOON...AND EVENING IN THE SOUTHEAST...AS THERE IS SOME
UNCERTAINTY WITH THE AREAL COVERAGE OF CONVECTION WITH THE FRONT.
IF MORNING PRECIPITATION CAN MOVE OUT AND CLOUDS BREAK UP THIS
AFTERNOON...SHOULD SEE AT LEAST 1000 TO 1500 J/KG OF MEAN LAYER CAPE
AND AROUND 50 KNOTS OR SO OF DEEP LAYER SHEAR. THIS IS CERTAINLY
SUPPORTIVE OF SEVERE CONVECTION...WITH LARGE HAIL AND DAMAGING WINDS
POSSIBLE. SPC HAS MOST OF THE AREA IN A SLIGHT RISK FOR SEVERE
STORMS THIS AFTERNOON AND EARLY THIS EVENING.
DRIER AIR WORKS INTO THE AREA LATER TONIGHT...BRINGING QUIETER
WEATHER. HIGHS TODAY WILL DEPEND ON AMOUNT OF CLOUDS LINGERING FROM
MORNING PRECIPITATION. WENT WITH UPPER 70S TO LOWER 80S FOR NOW.
LOWS TONIGHT SHOULD DROP INTO THE UPPER 50S TO LOWER/MID 60S.
TUESDAY AND WEDNESDAY...FORECAST CONFIDENCE...HIGH
IT LOOKS MAINLY DRY TUESDAY AND WEDNESDAY AS SURFACE HIGH PRESSURE
SLIDES THROUGH THE AREA. DID ADD A SLIGHT CHANCE FOR
SHOWERS/STORMS IN THE NORTH TUESDAY...AS MODELS NOW IN DECENT
AGREEMENT WITH A WEAK SHORTWAVE PASSING THROUGH. WARM TEMPS WILL
CONTINUE BOTH DAYS WITH HIGHS NEAR TO A FEW DEGREES ABOVE NORMAL.
WEDNESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM
BUMPED POPS UP WEDNESDAY NIGHT...AS MODELS ARE IN PRETTY GOOD
AGREEMENT IN BRINGING STRONG WARM AIR ADVECTION INTO SOUTHERN
WISCONSIN ON THE NOSE OF A 40-50 KT LLJ. LOOKS LIKE A SHORTWAVE
WILL ALSO BE MOVING THROUGH...WHICH SHOULD HELP TO FIRE OFF SOME
SHOWERS/STORMS.
THE PRECIP MAY HANG ON INTO THURSDAY MORNING...WITH MOST MODELS
THEN SHOWING A DRIER AND VERY WARM AFTERNOON IF THE SUN CAN COME
OUT. MODEL 925 MB TEMPS GET UP TO AROUND 25-26C...WHICH WOULD
RESULT IN HIGHS AROUND 90 GIVEN ENOUGH SUN. THROW IN DEWPOINTS IN
THE LOW 70S AND IT COULD END UP BEING AN UNCOMFORTABLE EARLY
SEPTEMBER DAY.
THE COLD FRONT IS EXPECTED TO MOVE THROUGH THURSDAY
NIGHT...BRINGING MORE THUNDERSTORM CHANCES. LINGERED SOME POPS
INTO FRIDAY DUE TO A COUPLE MODELS BEING A BIT SLOWER WITH THE
TIMING OF THE FRONT AND SHORTWAVE. SHOULD SEE HIGH TEMPS BACK DOWN
TO AROUND NORMAL FOR FRIDAY.
SATURDAY AND SUNDAY...FORECAST CONFIDENCE...MEDIUM
IT LOOKS COOLER AND DRY SATURDAY AND SUNDAY AS HIGH PRESSURE
SETTLES INTO THE GREAT LAKES REGION. TEMPERATURES WILL LIKELY BE
A FEW DEGREES BELOW NORMAL IF CURRENT MODEL FORECASTS VERIFY.
AVIATION/12Z TAFS/...
AREA OF SHOWERS AND A FEW STORMS WILL SHIFT EAST NORTHEAST THROUGH
THE AREA INTO THE MIDDLE MORNING HOURS. MAY SEE MVFR VISIBILITIES
AND CEILINGS WITH THESE SHOWERS. GUSTY SOUTH SOUTHWEST WINDS ARE
EXPECTED BY THE AFTERNOON HOURS...WITH GUSTS TO 25 KNOTS AT TIMES.
COLD FRONT WILL PUSH EASTWARD THROUGH TAF SITES BETWEEN 21Z TODAY
AND 03Z TUESDAY. SHOWERS AND STORMS ARE POSSIBLE ALONG AND AHEAD OF
THE FRONT. STRONG/SEVERE STORMS ARE POSSIBLE WITH HAIL AND GUSTY
WINDS. UNCERTAINTY EXISTS WITH THE AREAL COVERAGE OF STORMS...SO
WILL JUST USE VICINITY THUNDER WORDING FOR NOW IN TAFS. MVFR/IFR
VISIBILITIES AND CEILINGS ARE POSSIBLE IN ANY STORMS.
QUIET WEATHER WILL RETURN AFTER THE FRONTAL PASSAGE AND LINGER
THROUGH THE REST OF TONIGHT. LIGHT WINDS AND LINGERING MOISTURE MAY
BRING MVFR/IFR FOG AND CEILINGS TO THE AREA AFTER 06Z TUESDAY.
MARINE...
CANCELLED MARINE DENSE FOG ADVISORY EARLY...AS INCREASING SOUTH
WINDS SHOULD MIX OUT ANY LINGERING FOG NORTH OF NORTH POINT
LIGHTHOUSE.
SMALL CRAFT ADVISORY CONTINUES FOR THE NEARSHORE WATERS FROM 15Z
UNTIL 23Z TODAY. TIGHT PRESSURE GRADIENT WILL ALLOW FOR GUSTY SOUTH
SOUTHWEST WINDS TO 25 KNOTS AT TIMES. THIS WILL BRING WAVES OF 3 TO
5 FEET TOWARD THE OPEN WATERS. WINDS AND WAVES WILL SUBSIDE BY THIS
EVENING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...WOOD
TUESDAY THROUGH SUNDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
618 AM CDT MON SEP 1 2014
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 308 AM CDT MON SEP 1 2014
WATER VAPOR SATELLITE LOOP COUPLED WITH RAP ANALYSIS SHOWS VIGOROUS
MID-LEVEL TROUGH ROTATING THROUGH THE PLAINS TOWARD THE UPPER
MISSISSIPPI RIVER VALLEY. AT THE SURFACE 999MB LOWS WAS OVER WESTERN
ONTARIO WITH A COLD FRONT EXTENDING SOUTHWARD THROUGH MN/NW
IA/CENTRAL NEB. RADAR WAS LIT UP WITH SHOWERS/THUNDERSTORMS ACROSS
EASTERN MN INTO THE FORECAST AREA AHEAD OF THE MID-LEVEL WAVE AND
SURFACE COLD FRONT. OTHERWISE...TEMPERATURES ACROSS THE AREA EARLY
THIS MORNING WERE IN THE 60S.
LOOK FOR THE SURFACE COLD FRONT AND ASSOCIATED CONVECTION TO
CONTINUE PUSHING EAST ACROSS THE AREA THIS MORNING WITH THE BULK OF
THE RAIN EXITING EAST BY LATE MORNING. KEPT LINGERING AND
DIMINISHING CHANCES GOING HOWEVER INTO THE AFTERNOON AS THE MID-
LEVEL TROUGH/COLD AIR ALOFT POSSIBLY POPPING A FEW INSTABILITY
SHOWERS AND THUNDERSTORMS. NOT EXPECTING ANY SEVERE THREAT AS BEST
CAPE AND WIND SHEAR SHIFT EAST/SOUTHEAST OF THE AREA.
FOR TONIGHT...WILL SEE ANOTHER WEAK MID-LEVEL WAVE ROTATE TOWARD THE
AREA FROM THE NORTHERN PLAINS. NAM SHOWING A DECENT SHOT OF 700-
300MB PVA MOVING IN MAINLY WEST OF THE MISSISSIPPI RIVER AFTER
MIDNIGHT WITH BUFKIT SHOWING INSTABILITY/MOISTURE MAINLY CONFINED
ABOVE 800MB. KEPT A SMALL-END CHANCE OF SHOWERS/ISOLATED WEST OF THE
MISSISSIPPI AFTER MIDNIGHT BASED ON THIS SIGNAL. OVERNIGHT LOWS ARE
EXPECTED TO FALL INTO THE 50S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 308 AM CDT MON SEP 1 2014
A SMALL CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO
TUESDAY MAINLY NORTH OF I-94 AS THE WEAK MID-LEVEL TROUGH ROTATES
ACROSS THE FORECAST AREA. PLAN ON HIGHS RANGING FROM THE MIDDLE 70S
ACROSS NORTH CENTRAL WI...TO THE UPPER 70S/LOWER 80S ELSEWHERE.
SURFACE CYCLOGENESIS OVER THE NORTHERN PLAINS WILL PUSH A WARM FRONT
TOWARD THE AREA WEDNESDAY/WEDNESDAY NIGHT. ALL MODELS SHOW
INCREASING 850MB MOISTURE TRANSPORT/WARM AIR ADVECTION NOSING INTO
THE AREA WITH THE FRONT FOR INCREASING COVERAGE OF THUNDERSTORMS.
PRECIPITABLE WATER VALUES PUSHING 1.9 INCHES BY THURSDAY MORNING WITH
WARM CLOUD DEPTH LAYERS INCREASING INTO THE 4-4.5KM RANGE. BASED ON
THIS SIGNAL...WILL HAVE TO WATCH FOR A HEAVY RAINFALL POTENTIAL
ALONG WITH OTHER SEVERE THREATS AS WELL AS CAPE AND BULK SHEAR
INCREASE ALONG THE WARM FRONT. AT THIS POINT...MODELS SHOWING HIGHER
SEVERE POTENTIAL STAYING WEST OF THE MISSISSIPPI RIVER IN MORE
FAVORABLE CAPE/SHEAR ENVIRONMENT. WILL HAVE TO KEEP A CLOSE ON THIS
OVER THE NEXT COUPLE DAYS. LOOK FOR HIGHS ON WEDNESDAY TO TOP OFF IN
THE UPPER 70S TO MIDDLE 80S WITH DEW POINTS CREEPING UP INTO THE 65-
70 DEGREE RANGE.
THUNDERSTORM CHANCES CONTINUE THURSDAY INTO THURSDAY NIGHT AS THE
LOW PULLS NORTHEAST INTO ONTARIO CANADA...PUSHING A COLD FRONT
THROUGH THE AREA. THURSDAY WILL HAVE TO BE WATCHED CLOSELY AS WELL
FOR SEVERE POTENTIAL AS THE GFS IS SHOWING 0-6KM BULK SHEAR OF 30-
50KT COUPLED WITH MUCAPE POOL OF 2500-4500J/KG. HIGHS ON THURSDAY
AHEAD OF THE COLD FRONT ARE EXPECTED TO TOP OFF WELL INTO THE 80S
WITH DEW POINTS IN THE 70-75 DEGREE RANGE.
DRIER/COOLER AIR FILTERS INTO THE AREA FRIDAY AND INTO THE WEEKEND
AS CANADIAN HIGH PRESSURE BUILD INTO THE REGION. PLAN ON
TEMPERATURES BY THIS WEEKEND TO FEEL A BIT MORE LIKE FALL WITH HIGHS
IN THE 60S/LOWER 70S AND LOWS IN THE 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 618 AM CDT MON SEP 1 2014
SECOND ROUND OF CONVECTION HAS FORMED AHEAD OF THE FRONT AND
EXPECT THIS TO MOVE THROUGH BEFORE 12Z AT KRST AND KLSE BY 14Z.
IFR CONDITIONS WILL BE POSSIBLE IN THIS ACTIVITY. THE FRONT IS
THEN EXPECTED TO PUSH THROUGH SHORTLY BEHIND THE CONVECTION
SWINGING THE WINDS AROUND TO THE WEST AND ALLOWING AN AREA OF MVFR
CEILINGS TO MOVE IN. BOTH THE 01.06Z NAM AND 01.09Z RAP SUGGEST
THESE CEILINGS WILL ONLY LAST THROUGH THE MORNING BEFORE
SCATTERING OUT WITH VFR CONDITIONS THEN EXPECTED THROUGH THE REST
OF THE PERIOD. SOME CONCERN FOR FOG DEVELOPMENT LATE
TONIGHT...ESPECIALLY AT KLSE. FORECAST SOUNDINGS FROM THE NAM
INDICATE SATURATION MAY OCCUR AT THE SURFACE WITH A LIGHT WIND
PROFILE UP THROUGH ABOUT 25OO FEET OR SO. HOWEVER...UNSURE HOW
MUCH MID AND HIGH LEVEL CLOUDS MAY BE AROUND AHEAD OF AN
APPROACHING WEAK SHORT WAVE TROUGH. WILL LET LATER SHIFTS ACCESS
THIS POTENTIAL AND ADD IF NEEDED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
355 AM CDT MON SEP 1 2014
.TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.
AREA OF RAIN SHOWERS AND A FEW THUNDERSTORMS OVER SOUTHWEST
WISCONSIN...INTO FAR EASTERN IOWA AND FAR NORTHWEST ILLINOIS...HAS
BEEN SLOWLY WEAKENING OVER THE PAST FEW HOURS. THIS WAS BEING DRIVEN
BY 500 MB VORTICITY MAXIMUM MOVING INTO THE AREA...UPPER DIVERGENCE
WITH RIGHT REAR QUADRANT OF 250 MB JET STREAK...ALONG WITH 850 MB
LOW LEVEL JET. SPC MESOANALYSIS PAGE SHOWING A GOOD AMOUNT OF
CONVECTIVE INHIBITION OVER THE AREA...WHICH MAY BE HELPING WEAKEN
CONVECTION.
STILL...THE ABOVE MAIN FEATURES SHOULD CONTINUE TO BRING SOME
SHOWERS ACROSS THE AREA THROUGH THE MIDDLE MORNING HOURS. THIS IS
SUPPORTED BY THE HRRR AND OTHER MESOSCALE MODELS...THOUGH THEY AREA
SOMEWHAT OVERDONE WITH CURRENT PRECIPITATION TRENDS. THUS...WILL
CONTINUE HIGH POPS THROUGH THE MIDDLE MORNING HOURS FOR SHOWERS AND
ISOLATED STORMS.
MAIN ISSUE WILL BE CONVECTIVE TRENDS THIS AFTERNOON AND EVENING WITH
PASSING COLD FRONT AND SEVERE WEATHER POSSIBILITIES. COLD FRONT WILL
PASS EAST THROUGH THE AREA THIS AFTERNOON...EXITING THE SOUTHEAST BY
MIDDLE TO LATE EVENING. SYNOPTIC MODELS VARY A BIT IN THE TIMING OF
THE FRONT. FRONTOGENESIS RESPONSE WITH FRONT IS WEAK AS IT MOVES
THROUGH THE AREA...THOUGH ELONGATED 500 MB VORTICITY MAXIMUM PUSHES
INTO THE AREA FROM THE WEST. WENT WITH CHANCE POPS FOR THIS
AFTERNOON...AND EVENING IN THE SOUTHEAST...AS THERE IS SOME
UNCERTAINTY WITH THE AREAL COVERAGE OF CONVECTION WITH THE FRONT.
IF MORNING PRECIPITATION CAN MOVE OUT AND CLOUDS BREAK UP THIS
AFTERNOON...SHOULD SEE AT LEAST 1000 TO 1500 J/KG OF MEAN LAYER CAPE
AND AROUND 50 KNOTS OR SO OF DEEP LAYER SHEAR. THIS IS CERTAINLY
SUPPORTIVE OF SEVERE CONVECTION...WITH LARGE HAIL AND DAMAGING WINDS
POSSIBLE. SPC HAS MOST OF THE AREA IN A SLIGHT RISK FOR SEVERE
STORMS THIS AFTERNOON AND EARLY THIS EVENING.
DRIER AIR WORKS INTO THE AREA LATER TONIGHT...BRINGING QUIETER
WEATHER. HIGHS TODAY WILL DEPEND ON AMOUNT OF CLOUDS LINGERING FROM
MORNING PRECIPITATION. WENT WITH UPPER 70S TO LOWER 80S FOR NOW.
LOWS TONIGHT SHOULD DROP INTO THE UPPER 50S TO LOWER/MID 60S.
.TUESDAY AND WEDNESDAY...FORECAST CONFIDENCE...HIGH
IT LOOKS MAINLY DRY TUESDAY AND WEDNESDAY AS SURFACE HIGH PRESSURE
SLIDES THROUGH THE AREA. DID ADD A SLIGHT CHANCE FOR
SHOWERS/STORMS IN THE NORTH TUESDAY...AS MODELS NOW IN DECENT
AGREEMENT WITH A WEAK SHORTWAVE PASSING THROUGH. WARM TEMPS WILL
CONTINUE BOTH DAYS WITH HIGHS NEAR TO A FEW DEGREES ABOVE NORMAL.
.WEDNESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM
BUMPED POPS UP WEDNESDAY NIGHT...AS MODELS ARE IN PRETTY GOOD
AGREEMENT IN BRINGING STRONG WARM AIR ADVECTION INTO SOUTHERN
WISCONSIN ON THE NOSE OF A 40-50 KT LLJ. LOOKS LIKE A SHORTWAVE
WILL ALSO BE MOVING THROUGH...WHICH SHOULD HELP TO FIRE OFF SOME
SHOWERS/STORMS.
THE PRECIP MAY HANG ON INTO THURSDAY MORNING...WITH MOST MODELS
THEN SHOWING A DRIER AND VERY WARM AFTERNOON IF THE SUN CAN COME
OUT. MODEL 925 MB TEMPS GET UP TO AROUND 25-26C...WHICH WOULD
RESULT IN HIGHS AROUND 90 GIVEN ENOUGH SUN. THROW IN DEWPOINTS IN
THE LOW 70S AND IT COULD END UP BEING AN UNCOMFORTABLE EARLY
SEPTEMBER DAY.
THE COLD FRONT IS EXPECTED TO MOVE THROUGH THURSDAY
NIGHT...BRINGING MORE THUNDERSTORM CHANCES. LINGERED SOME POPS
INTO FRIDAY DUE TO A COUPLE MODELS BEING A BIT SLOWER WITH THE
TIMING OF THE FRONT AND SHORTWAVE. SHOULD SEE HIGH TEMPS BACK DOWN
TO AROUND NORMAL FOR FRIDAY.
.SATURDAY AND SUNDAY...FORECAST CONFIDENCE...MEDIUM
IT LOOKS COOLER AND DRY SATURDAY AND SUNDAY AS HIGH PRESSURE
SETTLES INTO THE GREAT LAKES REGION. TEMPERATURES WILL LIKELY BE
A FEW DEGREES BELOW NORMAL IF CURRENT MODEL FORECASTS VERIFY.
&&
.AVIATION/12Z TAFS/...
AREA OF SHOWERS AND A FEW STORMS WILL SHIFT EAST NORTHEAST THROUGH
THE AREA INTO THE MIDDLE MORNING HOURS. MAY SEE MVFR VISIBILITIES
AND CEILINGS WITH THESE SHOWERS. GUSTY SOUTH SOUTHWEST WINDS ARE
EXPECTED BY THE AFTERNOON HOURS...WITH GUSTS TO 25 KNOTS AT TIMES.
COLD FRONT WILL PUSH EASTWARD THROUGH TAF SITES BETWEEN 21Z TODAY
AND 03Z TUESDAY. SHOWERS AND STORMS ARE POSSIBLE ALONG AND AHEAD OF
THE FRONT. STRONG/SEVERE STORMS ARE POSSIBLE WITH HAIL AND GUSTY
WINDS. UNCERTAINTY EXISTS WITH THE AREAL COVERAGE OF STORMS...SO
WILL JUST USE VICINITY THUNDER WORDING FOR NOW IN TAFS. MVFR/IFR
VISIBILITIES AND CEILINGS ARE POSSIBLE IN ANY STORMS.
QUIET WEATHER WILL RETURN AFTER THE FRONTAL PASSAGE AND LINGER
THROUGH THE REST OF TONIGHT. LIGHT WINDS AND LINGERING MOISTURE MAY
BRING MVFR/IFR FOG AND CEILINGS TO THE AREA AFTER 06Z TUESDAY.
&&
.MARINE...
CANCELLED MARINE DENSE FOG ADVISORY EARLY...AS INCREASING SOUTH
WINDS SHOULD MIX OUT ANY LINGERING FOG NORTH OF NORTH POINT
LIGHTHOUSE.
SMALL CRAFT ADVISORY CONTINUES FOR THE NEARSHORE WATERS FROM 15Z
UNTIL 23Z TODAY. TIGHT PRESSURE GRADIENT WILL ALLOW FOR GUSTY SOUTH
SOUTHWEST WINDS TO 25 KNOTS AT TIMES. THIS WILL BRING WAVES OF 3 TO
5 FEET TOWARD THE OPEN WATERS. WINDS AND WAVES WILL SUBSIDE BY THIS
EVENING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 6 PM CDT THIS
EVENING FOR LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...WOOD
TUESDAY THROUGH SUNDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
308 AM CDT MON SEP 1 2014
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 308 AM CDT MON SEP 1 2014
WATER VAPOR SATELLITE LOOP COUPLED WITH RAP ANALYSIS SHOWS VIGOROUS
MID-LEVEL TROUGH ROTATING THROUGH THE PLAINS TOWARD THE UPPER
MISSISSIPPI RIVER VALLEY. AT THE SURFACE 999MB LOWS WAS OVER WESTERN
ONTARIO WITH A COLD FRONT EXTENDING SOUTHWARD THROUGH MN/NW
IA/CENTRAL NEB. RADAR WAS LIT UP WITH SHOWERS/THUNDERSTORMS ACROSS
EASTERN MN INTO THE FORECAST AREA AHEAD OF THE MID-LEVEL WAVE AND
SURFACE COLD FRONT. OTHERWISE...TEMPERATURES ACROSS THE AREA EARLY
THIS MORNING WERE IN THE 60S.
LOOK FOR THE SURFACE COLD FRONT AND ASSOCIATED CONVECTION TO
CONTINUE PUSHING EAST ACROSS THE AREA THIS MORNING WITH THE BULK OF
THE RAIN EXITING EAST BY LATE MORNING. KEPT LINGERING AND
DIMINISHING CHANCES GOING HOWEVER INTO THE AFTERNOON AS THE MID-
LEVEL TROUGH/COLD AIR ALOFT POSSIBLY POPPING A FEW INSTABILITY
SHOWERS AND THUNDERSTORMS. NOT EXPECTING ANY SEVERE THREAT AS BEST
CAPE AND WIND SHEAR SHIFT EAST/SOUTHEAST OF THE AREA.
FOR TONIGHT...WILL SEE ANOTHER WEAK MID-LEVEL WAVE ROTATE TOWARD THE
AREA FROM THE NORTHERN PLAINS. NAM SHOWING A DECENT SHOT OF 700-
300MB PVA MOVING IN MAINLY WEST OF THE MISSISSIPPI RIVER AFTER
MIDNIGHT WITH BUFKIT SHOWING INSTABILITY/MOISTURE MAINLY CONFINED
ABOVE 800MB. KEPT A SMALL-END CHANCE OF SHOWERS/ISOLATED WEST OF THE
MISSISSIPPI AFTER MIDNIGHT BASED ON THIS SIGNAL. OVERNIGHT LOWS ARE
EXPECTED TO FALL INTO THE 50S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 308 AM CDT MON SEP 1 2014
A SMALL CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO
TUESDAY MAINLY NORTH OF I-94 AS THE WEAK MID-LEVEL TROUGH ROTATES
ACROSS THE FORECAST AREA. PLAN ON HIGHS RANGING FROM THE MIDDLE 70S
ACROSS NORTH CENTRAL WI...TO THE UPPER 70S/LOWER 80S ELSEWHERE.
SURFACE CYCLOGENESIS OVER THE NORTHERN PLAINS WILL PUSH A WARM FRONT
TOWARD THE AREA WEDNESDAY/WEDNESDAY NIGHT. ALL MODELS SHOW
INCREASING 850MB MOISTURE TRANSPORT/WARM AIR ADVECTION NOSING INTO
THE AREA WITH THE FRONT FOR INCREASING COVERAGE OF THUNDERSTORMS.
PRECIPITABLE WATER VALUES PUSHING 1.9 INCHES BY THURSDAY MORNING WITH
WARM CLOUD DEPTH LAYERS INCREASING INTO THE 4-4.5KM RANGE. BASED ON
THIS SIGNAL...WILL HAVE TO WATCH FOR A HEAVY RAINFALL POTENTIAL
ALONG WITH OTHER SEVERE THREATS AS WELL AS CAPE AND BULK SHEAR
INCREASE ALONG THE WARM FRONT. AT THIS POINT...MODELS SHOWING HIGHER
SEVERE POTENTIAL STAYING WEST OF THE MISSISSIPPI RIVER IN MORE
FAVORABLE CAPE/SHEAR ENVIRONMENT. WILL HAVE TO KEEP A CLOSE ON THIS
OVER THE NEXT COUPLE DAYS. LOOK FOR HIGHS ON WEDNESDAY TO TOP OFF IN
THE UPPER 70S TO MIDDLE 80S WITH DEW POINTS CREEPING UP INTO THE 65-
70 DEGREE RANGE.
THUNDERSTORM CHANCES CONTINUE THURSDAY INTO THURSDAY NIGHT AS THE
LOW PULLS NORTHEAST INTO ONTARIO CANADA...PUSHING A COLD FRONT
THROUGH THE AREA. THURSDAY WILL HAVE TO BE WATCHED CLOSELY AS WELL
FOR SEVERE POTENTIAL AS THE GFS IS SHOWING 0-6KM BULK SHEAR OF 30-
50KT COUPLED WITH MUCAPE POOL OF 2500-4500J/KG. HIGHS ON THURSDAY
AHEAD OF THE COLD FRONT ARE EXPECTED TO TOP OFF WELL INTO THE 80S
WITH DEW POINTS IN THE 70-75 DEGREE RANGE.
DRIER/COOLER AIR FILTERS INTO THE AREA FRIDAY AND INTO THE WEEKEND
AS CANADIAN HIGH PRESSURE BUILD INTO THE REGION. PLAN ON
TEMPERATURES BY THIS WEEKEND TO FEEL A BIT MORE LIKE FALL WITH HIGHS
IN THE 60S/LOWER 70S AND LOWS IN THE 50S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1144 PM CDT SUN AUG 31 2014
01.0430Z RADAR SHOWS A LARGE SWATH OF MODERATE TO HEAVY RAIN WITH
EMBEDDED THUNDER ALONG AND WEST OF THE MISSISSIPPI RIVER. BACK
EDGE OF THIS PRECIPITATION IS JUST WEST OF KRST SUCH THAT DRY
CONDITIONS ARE EXPECTED NO LATER THAN 01.07Z AT KRST AND 01.09Z AT
KLSE. WITH SATURATED NEAR SURFACE LAYER...EXPECT CEILINGS TO LOWER
OVERNIGHT WITH MVFR VISIBILITY IN MIST. CONDITIONS EXPECTED TO
SLOWLY IMPROVE LABOR DAY MORNING...BUT REMAIN MVFR THROUGH MUCH OF
THE DAY...FINALLY IMPROVING TO VFR BY 02.00Z. WINDS WILL SHIFT TO
THE NORTHWEST AFTER FRONTAL PASSAGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1154 PM CDT SUN AUG 31 2014
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
AND NEW INFORMATION ADDED TO UPDATE SECTION
.UPDATE...
ISSUED AT 1148 PM CDT SUN AUG 31 2014
HAVE CONTINUED TO HIT LOWER VISBY AT LAKESHORE WITH SPS AS NOT
WIDESPREAD ENOUGH TO GO WITH ADVISORY. IS STARTING TO IMPROVE IN
MANITOWOC AND WILL CONTIUE TO IMPROVE NEXT HOUR OR SO. WILL BE
WATCHING AREA OF STORMS/SHOWERS MOVING THROUGH SOUTHERN WI. WINDS
AT LEAD EDGE STILL RATHER STRONG.
&&
.SYNOPSIS...
ISSUED AT 218 PM CDT SUN AUG 31 2014
WARM AND RATHER HUMID WITH SHOWERS AND THUNDERSTORMS AT TIMES FOR
THE REST OF THE HOLIDAY WEEKEND AND THROUGH THE UPCOMING WORK
WEEK.
STG SUBTROPICAL RIDGE ACRS THE SRN CONUS WL EXPAND NWD A BIT AS
SOMEWHAT PROGRESSIVE BAND OF WESTERLIES GRADUALLY RECEDES NWD
DURING THE PERIOD. NOTHING SPECIAL ABOUT THIS PATTERN FOR THIS
TIME OF YEAR...AS THE WESTERLIES ARE TYPICALLY STRONGER THAN
DURING THE MIDDLE SUMMER...BUT ARE STILL USUALLY CENTERED N OF THE
AREA.
THE PRIMARY FRONTAL ZONE SEPARATING WARM AND VERY MOIST TROPICAL
AIR TO THE S FM COOLER AND DRIER CANADIAN AIR TO THE N WL REMAIN
STETCHED OUT W-E ALONG THE SRN EDGE OF THE MAIN WESTERLIES...AND
CLOSE TO THE FCST AREA MUCH OF THE TIME. THIS WL RESULT IN
SEVERAL OPPORTUNITIES FOR PCPN...LIKELY RESULTING IN ABV NORMAL
AMNTS. TEMPS ARE EXPECTED TO REMAIN AOA NORMAL FOR MUCH OF THE
FCST PERIOD BEFORE DROPPING BACK CLOSE TO NORMAL LATE. IT WILL
ALSO BE HUMID AT TIMES.
&&
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 218 PM CDT SUN AUG 31 2014
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW
PRESSURE MOVING NORTHEAST OVER FAR NORTHWEST MINNESOTA AND A COLD
FRONT MOVING EASTWARD FROM THE LOW TO THE CENTRAL GREAT PLAINS.
STORMS HAVE BEGUN TO FIRE ALONG THE FRONT OVER SOUTH CENTRAL
MINNESOTA...BUT THE ATMOSPHERE IS STRUGGLING TO DESTABILIZE DUE IN
PART TO A PRONOUNCED CAP AND DRY AIR ON THE 18Z MINNEAPOLIS
SOUNDING. HOWEVER...AS A SHORTWAVE OVER NEBRASKA MOVES INTO THE
NORTHERN MISSISSIPPI VALLEY...THE CAP IS EXPECTED TO WEAKEN LATE
THIS AFTERNOON THAT WILL RESULT IN A FAVORABLE ENVIRONMENT FOR
SEVERE STORMS. THESE STORMS COULD MOVE INTO NORTH-CENTRAL WISCONSIN
LATER THIS EVENING. THE MAIN SHORTWAVE IS MOVING EAST OVER EASTERN
WYOMING AND ANTICIPATED TO ARRIVE INTO WISCONSIN LATE TONIGHT INTO
MONDAY MORNING...ALONG WITH THE COLD FRONT. THUNDERSTORM TIMING AND
IMPACTS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...A COLD FRONT WILL SLOWLY MOVE ACROSS THE NORTHERN
MISSISSIPPI VALLEY AS IT WAITS FOR A SHORTWAVE OVER WYOMING TO GIVE
IT A FORWARD PUSH. ASSUMING STRONG TO SEVERE CONVECTION AHEAD OF
THE FRONT DEVELOPS AS PLANNED LATER THIS AFTERNOON INTO THIS
EVENING...GUIDANCE SUGGESTS THIS CONVECTION WILL MAKE A RUN AT
NORTH-CENTRAL WISCONSIN LATE THIS EVENING...THOUGH WILL BE WEAKENING
AS DIURNAL INSTABILITY IS LOST. MODELS SUGGEST AROUND 1000 J/KG OF
ELEVATED CAPE WILL BE PRESENT AS THIS CONVECTION APPROACHES THE
NORTHWEST FORECAST AREA SO NOT OUT OF THE QUESTION THAT A FEW STRONG
STORMS COULD REACH NORTH-CENTRAL WISCONSIN. AN ISOLATED SEVERE
STORM CANNOT BE RULED OUT...MAINLY FOR DAMAGING WINDS AND LARGE
HAIL. WOULDNT BE SURPRISE TO SEE A FEW HOUR BREAK OVERNIGHT BETWEEN
THIS CONVECTION AS IT WEAKENS/LIFTS TO THE NORTHEAST...AND A MORE
WIDESPREAD AREA OF SHOWERS AND THUNDERSTORMS AHEAD OF THE MAIN
SHORTWAVE WHICH WILL MOVE INTO THE NORTHERN MISSISSIPPI VALLEY BY
12Z. THIS AREA OF PRECIP SHOULD MOVE ACROSS CENTRAL AND
NORTH-CENTRAL WI LATE TONIGHT. ELEVATED CAPES LOOK TO BE APPROX 500
J/KG SO NOT ANTICIPATING SEVERE CONVECTION. LOWS MAINLY IN THE
MIDDLE 60S.
MONDAY...THE SHORTWAVE TROUGH WILL LIFT NORTHEAST ACROSS WISCONSIN
MONDAY MORNING...DRIVING THE AREA OF SHOWERS AND THUNDERSTORMS
ACROSS NORTH-CENTRAL AND NORTHEAST WISCONSIN. THE HEAVIEST RAINFALL
LOOKS TO OCCUR OVER CENTRAL AND NORTH-CENTRAL WISCONSIN WITH THIS
EVENT AND COULD SEE AN INCH TO 1.50 INCHES IF CONVECTION REACHES
INTO THIS AREA THIS EVENING. WITH PRECIPITATION OCCURRING DURING
THE MORNING AND THE SHORTWAVE LIFTING NORTHEAST OF THE AREA IN THE
AFTERNOON...SEEMS LIKE AN AWFULLY SMALL TIME PERIOD FOR
REDEVELOPMENT OF STORMS ALONG THE COLD FRONT OVER NORTHEAST
WISCONSIN. THE BEST BET MAY BE TO HAVE STORMS CONTINUOUSLY REFIRE
ALONG THE TAIL OF THE SHORTWAVE...BUT THIS ADMITTEDLY SEEMS LIKE
A SMALL CHANCE SINCE THE ATMOSPHERE WILL HAVE BEEN WORKED OVER
BY THIS TIME...AND PRECIPITATION WILL HAVE SQUASHED SURFACE BASED
INSTABILITY. AS A RESULT...SPC HAS SHIFTED THE SLIGHT RISK OF
SEVERE WEATHER TO THE SOUTH AND EAST OF THE FORECAST AREA AND THIS
SEEMS REASONABLE. WILL MENTION THE CHANCE OF GUSTY WINDS AND SMALL
HAIL BUT LEAVE THE THREAT OF SEVERE WEATHER OUT OF THE HWO.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 218 PM CDT SUN AUG 31 2014
SOME LINGERING PCPN WL BE POSSIBLE MON EVENING...MAINLY OVER E-C
WI. CARRIED CHC POPS INTO THE EARLY EVENING. WHILE ISOLD SHRA
COULD LINGER WELL INTO THE NGT...THE MAIN POOL OF INSTABILITY WL
BE WELL S BY THEN...SO OPTED TO GO WITH A DRY FCST AFTER MIDNIGHT.
LATER SHIFTS MAY NEED TO TAKE ANOTHER LOOK AT THAT.
THERE ARE PROS AND CONS FOR PCPN CHCS TUE. ON ONE HAND...UPR TROF
WL STILL BE ACRS THE AREA DURING THE MORNING...AND WNWLY UPR FLOW
WL KEEP MODEST MID-LVL LAPSE RATES ACRS THE RGN. ON THE OTHER...
UPR HEIGHTS WL BE RISING AS THE TROF SHIFTS E...AND QG FORCING
WL BE FAVORING SUBSIDENCE. OPTED TO KEEP FAIRLY LOW POPS...BUT
WENT WITH ISOLD SHRA ACRS ALL BUT THE FAR SRN PART OF THE AREA.
PCPN UNLIKELY TO BE A BIG DEAL...BUT CONFIDENCE IN TOTALLY DRY DAY
ISN/T THAT GREAT EITHER.
UPR HEIGHTS SHOULD CONT TO RISE TUE NGT/WED. STAYED DRY TUE NGT...
BUT N-C WI WL BE CLOSE ENOUGH TO THE RETURN FLOW TO JUSTIFY
HAVING A CHC OF TSRA WED.
WENT WITH A BLEND OF TOP PERFORING GUIDANCE PRODUCTS FOR TEMPS...
WHICH WERE DOMINATED BY THE ECMWF AND IT/S MOS AND BIAS-CORRECTED
DERIVATIVES.
NO SIG CHGS NEED TO BROAD-BASED EXTENDED FCST INITIALIZATION
GRIDS.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1148 PM CDT SUN AUG 31 2014
IMPROVING CONDITIONS AT LAKESHORE AS WINDS INCREASE OVERNIGHT.
SHOWERS AND STROMS AHEAD OF A COLD FRONT WILL MOVE ACROSS THE
REGION LATE TONIGHT INTO MONDAY...SCATTERED MVFR CIGS AND
VSBYS...LOCALLY IFR...WILL DEVELOP DUE TO HEAVY RAIN AND POSSIBLE
THUNDERSTORMS. SOME STORMS MAY CONTAIN STRONG GUSTY WINDS AS THEY
MOVE INTO CENTRAL AND NORTH-CENTRAL WISCONSIN OVERNIGHT. HAVE
ADDED SOME LLWS AS LOW LEVEL JET STRENGTHENS OVERNIGHT. IMPROVING
CONDITIONS EXPECTED BY MON AFTN. &&
.GRB WATCHES/WARNINGS/ADVISORIES...
BEACH HAZARDS STATEMENT FROM 8 AM CDT MONDAY THROUGH MONDAY
EVENING FOR WIZ022-040-050.
&&
$$
UPDATE.........TE
SYNOPSIS.......SKOWRONSKI
SHORT TERM.....MPC
LONG TERM......SKOWRONSKI
AVIATION.......TE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
657 PM MDT TUE SEP 2 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 420 PM MDT TUE SEP 2 2014
MAIN FORECAST CONCERN OVER THE NEXT FEW DAYS WILL BE THE
CRITICAL FIRE WEATHER CONDITIONS ACROSS THE CWA. IT TOOK A LITTLE
WHILE FOR RH VALUES TO DROP TO CRITICAL LEVELS THIS
AFTERNOON...BUT WE ARE CURRENTLY SEEING A RH OF AROUND 15 PERCENT
IN THE FOOTHILLS OF THE LARAMIE RANGE (FIRE WEATHER ZONES 309 AND
301). RH VALUES ARE GENERALLY 15-20 PERCENT TO THE WEST OF THE
LARAMIE RANGE. WITH GUSTS TO 25-30 MPH THROUGH EARLY
EVENING...THIS CONTINUES TO LOOK LIKE A MARGINAL RED FLAG EVENT
AND WILL KEEP THE WARNINGS GOING. CLOUD COVER THIS AFTERNOON IS
QUITE LIMITED WITH ONLY ISOLATED CUMULUS. SFC MOISTURE IS BETTER
IN SOUTHERLY WINDS JUST TO THE EAST OF THE CWA (DEUEL AND GARDEN
COUNTIES) BUT IT WILL BE TOUGH TO ADVECT THIS MOISTURE WESTWARD.
THE HRRR MODEL ALONG WITH THE OTHER MODELS DO NOT SHOW ANY QPF
OVER THE PANHANDLE TONIGHT SO WILL KEEP SLIGHT CHANE POPS OUT OF
THE FCST.
WEDNESDAY CONTINUES TO LOOK LIKE A MORE CRITICAL FIRE WEATHER DAY
OVER THE REGION. A SHORTWAVE MOVING FROM WASHINGTON INTO MONTANA
WILL INDUCE PRESSURE FALLS OVER WESTERN SOUTH DAKOTA WHICH
STRENGTHENS THE PRESSURE GRADIENT OVER ESPECIALLY SOUTHEAST WY.
MOS GUIDANCE SHOWS WINDS ABOUT 5 KTS HIGHER THAN THIS AFTN ALONG
WITH AN ADDITIONAL 5 DEGREES OF WARMING. THE FIRE WEATHER WATCH
FOR TOMORROW AFTN INCLUDES TWO ZONES (310 AND 306) THAT ARE NOT
INCLUDED IN TODAYS RED FLAG WARNING. THIS LOOKS GOOD SINCE BOTH
THESE ZONES WERE CLOSE TO HITTING THE CRITERIA TODAY AND
CONDITIONS WILL BE DRIER AND MORE BREEZY TOMORROW. THE DEEP
SOUTHWESTERLY FLOW WILL RESULT IN A VERY WARM DAY WITH HIGHS
RISING INTO THE UPPER 80S TO MID 90S ACROSS THE PLAINS. THIS COULD
BE ONE OF THE WARMEST DAYS FOR THE REST OF THE YEAR SINCE A COLD
FRONTAL PASSAGE IS STILL PROGGED FOR THURS MORNING. TEMPS WILL
DROP CLOSE TO 20 DEGREES ON THURS. STILL NO GOOD CHANCE OF PRECIP
THROUGH AT LEAST THURS EVENING. COULD BE ISOLATED SHOWERS
DEVELOPING BY THURS NIGHT ALTHOUGH THE MODEL TREND HAS BEEN TO
SHIFT THE MORE WIDESPREAD RAIN WELL TO THE SOUTH OVER NORTHWEST KS.
.LONG TERM...(FRIDAY THROUGH MONDAY NIGHT)
ISSUED AT 420 PM MDT TUE SEP 2 2014
MODELS ARE IN FAIR AGREEMENT WITH THE MEDIUM RANGE PERIOD SHOWING A
PERSISTENT QUASI-ZONAL PATTERN OVER THE CENTRAL CONUS. TEMPERATURES
WILL START OFF BELOW AVERAGE ON FRIDAY IN THE POST FRONTAL
AIRMASS...WITH THE SFC HIGH SLIDING TO THE SOUTHEAST ACROSS THE
CENTRAL PLAINS. SFC WINDS ACROSS THE HIGH PLAINS WILL BE OUT OF THE
SOUTHEAST AS THE SFC HIGH SLIDES SOUTHEAST...WITH CONVECTION
DEVELOPING OVER THE MOUNTAINS IN THE LATE AFTERNOON IN THIS LLVL
UPSLOPE REGIME. SHOULD STAY FAIRLY CAPPED ACROSS THE PLAINS WITHIN
THE COOLER AIRMASS...BUT CANT RULE OUT SHOWERS/WEAK TSTORMS
MAINTAINING AS THEY MOVE OFF THE MOUNTAINS AS A 70 KT JET AND
SHORTWAVE ENERGY WILL BE MOVING OVERHEAD AT THIS TIME. SATURDAY
LOOKS VERY SIMILAR ALBEIT WITH WEAKER UPSLOPE FLOW AND SLIGHTLY
WARMER TEMPS/HIGH INSTABILITY. SUNDAY AND MONDAY COULD SEE A BIT
MORE SUBTROPICAL MOISTURE ADVECT UP FROM THE SOUTHWEST AS A TROUGH
DIGS ALONG THE WEST COAST AND MOVES ACROSS THE GREAT BASIN. THE
DEEPEST MOISTURE LOOKS TO REMAIN TO OUR SOUTH...BUT CAN SEE SOME OF
THIS MOISTURE MAKING IT UP TO SOUTHERN PORTIONS OF THE CWA SO WILL
MAINTAIN AT LEAST SLIGHT CHANCE POPS FOR MUCH OF THE CWA. TEMPS WILL
INCREASE BACK TO MORE NORMAL VALUES FOR THIS TIME OF YEAR BY MONDAY
AS THE UPPER TROUGH DEEPENS AND A WARM AIR ADVECTION PATTERN
DEVELOPS OVER THE ROCKIES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY AFTERNOON)
ISSUED AT 644 PM MDT TUE SEP 2 2014
VFR CONDITIONS TO PREVAIL THRU THE PERIOD. WINDS WILL SUBSIDE
AROUND 02Z...BUT BECOME GUSTY AFTER 16Z WEDNESDAY.
&&
.FIRE WEATHER...
ISSUED AT 649 PM MDT TUE SEP 2 2014
PER OUR FIRE WEATHER BRIEFING AND MODEL GUIDANCE...RED FLAG
CONDITIONS LOOKING EVEN MORE LIKELY FOR PORTIONS OF SOUTHEAST
WYOMING ON WEDNESDAY...THUS WE HAVE UPGRADED THE FIRE WEATHER
WATCH TO A RED FLAG WARNING...AND HAVE ALSO CANCELLED THE RED
FLAG WARNING THAT WAS IN EFFECT FOR THIS AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM NOON TO 7 PM MDT WEDNESDAY FOR WYZ301-302-
304-306-309-310.
NE...NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...RJM
AVIATION...HAHN
FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
644 PM MDT TUE SEP 2 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 420 PM MDT TUE SEP 2 2014
MAIN FORECAST CONCERN OVER THE NEXT FEW DAYS WILL BE THE
CRITICAL FIRE WEATHER CONDITIONS ACROSS THE CWA. IT TOOK A LITTLE
WHILE FOR RH VALUES TO DROP TO CRITICAL LEVELS THIS
AFTERNOON...BUT WE ARE CURRENTLY SEEING A RH OF AROUND 15 PERCENT
IN THE FOOTHILLS OF THE LARAMIE RANGE (FIRE WEATHER ZONES 309 AND
301). RH VALUES ARE GENERALLY 15-20 PERCENT TO THE WEST OF THE
LARAMIE RANGE. WITH GUSTS TO 25-30 MPH THROUGH EARLY
EVENING...THIS CONTINUES TO LOOK LIKE A MARGINAL RED FLAG EVENT
AND WILL KEEP THE WARNINGS GOING. CLOUD COVER THIS AFTERNOON IS
QUITE LIMITED WITH ONLY ISOLATED CUMULUS. SFC MOISTURE IS BETTER
IN SOUTHERLY WINDS JUST TO THE EAST OF THE CWA (DEUEL AND GARDEN
COUNTIES) BUT IT WILL BE TOUGH TO ADVECT THIS MOISTURE WESTWARD.
THE HRRR MODEL ALONG WITH THE OTHER MODELS DO NOT SHOW ANY QPF
OVER THE PANHANDLE TONIGHT SO WILL KEEP SLIGHT CHANE POPS OUT OF
THE FCST.
WEDNESDAY CONTINUES TO LOOK LIKE A MORE CRITICAL FIRE WEATHER DAY
OVER THE REGION. A SHORTWAVE MOVING FROM WASHINGTON INTO MONTANA
WILL INDUCE PRESSURE FALLS OVER WESTERN SOUTH DAKOTA WHICH
STRENGTHENS THE PRESSURE GRADIENT OVER ESPECIALLY SOUTHEAST WY.
MOS GUIDANCE SHOWS WINDS ABOUT 5 KTS HIGHER THAN THIS AFTN ALONG
WITH AN ADDITIONAL 5 DEGREES OF WARMING. THE FIRE WEATHER WATCH
FOR TOMORROW AFTN INCLUDES TWO ZONES (310 AND 306) THAT ARE NOT
INCLUDED IN TODAYS RED FLAG WARNING. THIS LOOKS GOOD SINCE BOTH
THESE ZONES WERE CLOSE TO HITTING THE CRITERIA TODAY AND
CONDITIONS WILL BE DRIER AND MORE BREEZY TOMORROW. THE DEEP
SOUTHWESTERLY FLOW WILL RESULT IN A VERY WARM DAY WITH HIGHS
RISING INTO THE UPPER 80S TO MID 90S ACROSS THE PLAINS. THIS COULD
BE ONE OF THE WARMEST DAYS FOR THE REST OF THE YEAR SINCE A COLD
FRONTAL PASSAGE IS STILL PROGGED FOR THURS MORNING. TEMPS WILL
DROP CLOSE TO 20 DEGREES ON THURS. STILL NO GOOD CHANCE OF PRECIP
THROUGH AT LEAST THURS EVENING. COULD BE ISOLATED SHOWERS
DEVELOPING BY THURS NIGHT ALTHOUGH THE MODEL TREND HAS BEEN TO
SHIFT THE MORE WIDESPREAD RAIN WELL TO THE SOUTH OVER NORTHWEST KS.
.LONG TERM...(FRIDAY THROUGH MONDAY NIGHT)
ISSUED AT 420 PM MDT TUE SEP 2 2014
MODELS ARE IN FAIR AGREEMENT WITH THE MEDIUM RANGE PERIOD SHOWING A
PERSISTENT QUASI-ZONAL PATTERN OVER THE CENTRAL CONUS. TEMPERATURES
WILL START OFF BELOW AVERAGE ON FRIDAY IN THE POST FRONTAL
AIRMASS...WITH THE SFC HIGH SLIDING TO THE SOUTHEAST ACROSS THE
CENTRAL PLAINS. SFC WINDS ACROSS THE HIGH PLAINS WILL BE OUT OF THE
SOUTHEAST AS THE SFC HIGH SLIDES SOUTHEAST...WITH CONVECTION
DEVELOPING OVER THE MOUNTAINS IN THE LATE AFTERNOON IN THIS LLVL
UPSLOPE REGIME. SHOULD STAY FAIRLY CAPPED ACROSS THE PLAINS WITHIN
THE COOLER AIRMASS...BUT CANT RULE OUT SHOWERS/WEAK TSTORMS
MAINTAINING AS THEY MOVE OFF THE MOUNTAINS AS A 70 KT JET AND
SHORTWAVE ENERGY WILL BE MOVING OVERHEAD AT THIS TIME. SATURDAY
LOOKS VERY SIMILAR ALBEIT WITH WEAKER UPSLOPE FLOW AND SLIGHTLY
WARMER TEMPS/HIGH INSTABILITY. SUNDAY AND MONDAY COULD SEE A BIT
MORE SUBTROPICAL MOISTURE ADVECT UP FROM THE SOUTHWEST AS A TROUGH
DIGS ALONG THE WEST COAST AND MOVES ACROSS THE GREAT BASIN. THE
DEEPEST MOISTURE LOOKS TO REMAIN TO OUR SOUTH...BUT CAN SEE SOME OF
THIS MOISTURE MAKING IT UP TO SOUTHERN PORTIONS OF THE CWA SO WILL
MAINTAIN AT LEAST SLIGHT CHANCE POPS FOR MUCH OF THE CWA. TEMPS WILL
INCREASE BACK TO MORE NORMAL VALUES FOR THIS TIME OF YEAR BY MONDAY
AS THE UPPER TROUGH DEEPENS AND A WARM AIR ADVECTION PATTERN
DEVELOPS OVER THE ROCKIES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY AFTERNOON)
ISSUED AT 644 PM MDT TUE SEP 2 2014
VFR CONDITIONS TO PREVAIL THRU THE PERIOD. WINDS WILL SUBSIDE
AROUND 02Z...BUT BECOME GUSTY AFTER 16Z WEDNESDAY.
&&
.FIRE WEATHER...
ISSUED AT 420 PM MDT TUE SEP 2 2014
RELATIVE HUMIDITY VALUES HAVE DROPPED TO AROUND 15 PERCENT THIS
AFTERNOON OVER LOWER ELEVATIONS OF SOUTHEAST WYOMING. IN
ADDITION...WEST AND SOUTHWEST WINDS HAVE BEEN GUSTING TO 20-30
MPH. A RED FLAG WARNING REMAINS IN EFFECT THROUGH EARLY THIS
EVENING OVER PORTIONS OF SOUTHEAST WYOMING. TEMPERATURES WILL WARM
ON WEDNESDAY AND WINDS WILL BE MORE BREEZY DURING THE AFTERNOON
DUE TO A STRENGTHENING PRESSURE GRADIENT. THUS...EXPECT CRITICAL
FIRE WEATHER CONDITIONS TO BE MORE WIDESPREAD OVER SOUTHEAST
WYOMING AND FIRE WEATHER WATCHES ARE IN EFFECT. AN ELEVATED FIRE
WEATHER THREAT IS PREDICTED OVER THE WESTERN NEBRASKA PANHANDLE
DUE TO HUMIDITY VALUES FALLING TO 15-20 PERCENT AND WIND GUSTS OF
20-25 MPH DURING THE AFTERNOON. A COLD FRONT ON THURSDAY MORNING
WILL PUSH ACROSS THE AREA WITH MUCH COOLER TEMPERATURES FOR
THURSDAY AND INTO THE WEEKEND.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR WYZ301-302-304-306-309-310.
RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301-302-304-
309.
NE...NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...RJM
AVIATION...HAHN
FIRE WEATHER...FINCH
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
425 AM EDT WED SEP 3 2014
...SCATTERED TO NUMEROUS THUNDERSTORMS TODAY...
.CURRENTLY...
DEEP LAYER RIDGING HAS SHIFTED A BIT FURTHER W SINCE TUE AFTN
AS A MID TO UPPER LEVEL LOW OVER THE SW BAHAMAS IMPINGES ON THE
REGION. AN ATLC SFC RIDGE EXTENDS INTO NRN FL AND CENTRAL GULF COAST.
DEEP LAYER MOISTURE REMAINS IN PLACE WITH PWATS NEAR 2 INCHES PER
00Z RAOB WITH GPS MET DATA SHOWING SLIGHTLY LOWER VALUES. SFC TEMPS
ARE COOLER THAN 24 HRS AGO AND WITH RECENT RAINFALL OVER INLAND
AREAS THERE IS A GOOD CHANCE OF SOME PATCHY FOG DEVELOPING THROUGH
EARLY MORNING. SOME DEBRIS CLOUDS AOA 20 KFT EXPECTED TO SLOWLY
DISSIPATE FROM TUE EVENINGS CONVECTION. LATEST RADAR SHOWS A FEW
SHOWERS OFFSHORE FROM 20NM AND BEYOND LIFTING NWD.
TODAY...A RELATIVELY SIMILAR ENVIRONMENT TO YESTERDAY WITH ELEVATED
MOISTURE LEVELS AND A LIGHT WIND FLOW REGIME ENABLING SEA BREEZES
TO BECOME ACTIVE ONCE AGAIN. A FEW SHOWERS AND STORMS OVER THE
COASTAL WATERS WILL SLOWLY DIMINISH DURING THE DAY DUE TO THE
DEVELOPMENT OF THE E COAST SEA BREEZE. DEEP LAYER FLOW WILL BE WEAK
GENERALLY LESS THAN 5 KNOTS...WITH RIDGING HOLDS WHILE MID TO UPPER
LOW AND TROUGH OVER CUBA AND SRN FL SLOWLY TREKS WWD. MEAN LAYER
WINDS BEGIN TO BECOME ELY BY EARLY EVENING HOURS. THE HRRR MODEL AND
GFS SUGGEST ANOTHER EARLY START TO DEVELOPMENT OF SHOWERS AND
STORMS...MAINLY ALONG AND NEAR THE E COAST SEA BREEZE AROUND
15Z-17Z...AND THEN FAIRLY STEADY INCREASE IN COVERAGE THROUGH THE
AFTN OVER INLAND AREAS. HAVE INCREASED POPS AREA-WIDE TO AROUND
40-60% RANGE WITH SOME HIGH END LIKELY POPS POSSIBLE NEAR THE I-75
CORRIDOR BY LATE AFTN DUE TO INTERACTIONS OF W COAST SEA
BREEZE...OUTFLOWS AND E COAST SEA BREEZE. SIMILAR THREATS
FROM STORMS FROM YESTERDAY...FREQUENT/EXCESSIVE LIGHTNING...LOCALLY
HEAVY RAIN...AND GUSTY WINDS. HIGHS ARE NUDGE DOWNWARD DUE TO
SLIGHTLY LOWER 850 MB TEMPS AND INCREASED DEEP CONVECTIVE
ACTIVITY...WITH LOWER 90S INLAND AND 88-90 AT THE COAST.
TONIGHT...ISOLD TO SCT CONVECTION EXPECTED IN THE EVENING HOURS
BEFORE FADING AFTER MIDNIGHT. THE GFS SHOWS A DRY SLOT NW OF THE
TROUGH TO OUR S SLIDING UP THROUGH OUR FORECAST AREA BY 12Z THU.
THIS WILL ENABLE SOME CLEARING SKIES AND DRY CONDITIONS FILTERING
INTO THE AREA. DESPITE THIS...ARW AND NMM MODELS AS WELL AS THE EURO
MODEL INDICATE ISOLD TO SCT SHOWERS AND STORMS POSSIBLE OVER THE
COASTAL WATERS FROM LOW LEVEL MOISTURE CONVERGENCE. SOME OF THIS
ACTIVITY MAY DRIFT INTO THE BEACHES AND INTRACOASTAL WATERWAY NEAR
OR BEFORE SUNRISE. PATCHY FOG POSSIBLE WELL INLAND AND LOWS MAINLY
LOWER TO MID 70S.
THURSDAY...MUCH DRIER CONDITIONS IN THE MID AND UPPER LEVELS WILL
SHIFT NWWD OVER THE CWA AND HELP LIMIT CONVECTIVE COVERAGE TO AROUND
20-40% WITH A SLIGHTLY HIGHER CHANCE OVER S ZONES WHERE THERE WILL
BE LESS SUBSIDENCE AND MORE MOISTURE AVAILABLE. MEAN FLOW MORE ELY
AND INCREASED A FEW KNOTS HELPING TO PUSH THE E COAST SEA BREEZE
INLAND MORE QUICKLY THAN TODAY. HIGHS CONTINUE IN THE LOWER 90S MOST
LOCATIONS.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...
DEEP MOISTURE WILL INCREASE FROM SOUTH TO NORTH DURING THIS
TIME FRAME AS A WEAKENING TUTT FEATURE MOVES INTO THE
SOUTHEASTERN GULF OF MEXICO...AND A WEAK SURFACE REFLECTION
SLIDES NORTHWARD UP THE FL PENINSULA. INCREASED NOCTURNAL POPS
TO HIGH-END CHANCE OVER THE COASTAL WATERS THURS NIGHT...AND
ADDED CHANCE POPS IN THE COASTAL COUNTIES AND NORTH CENTRAL
FL ON FRI MORNING AS ENHANCED MOISTURE ADVECTS INTO THESE AREAS.
LOWS WILL GENERALLY FALL INTO THE LOWER 70S INLAND...WITH UPPER
70S AT THE COAST. EXPECTING NUMEROUS COVERAGE ALONG THE I-75
CORRIDOR DURING THE AFTERNOON HOURS...WITH DECREASING POPS
TOWARDS THE EARLY EVENING HOURS IN THE COASTAL COUNTIES AS THE
ATLANTIC SEA BREEZE PUSHES WELL INLAND. INCREASING POPS AND CLOUD
COVER SHOULD HOLD HIGHS IN THE UPPER 80S ACROSS MOST OF NORTH
CENTRAL AND NE FL...AND NEAR 90 IN SE GA. SOUTHERLY FLOW BEHIND
THE WEAK SURFACE WAVE WILL LIKELY PUSH ACTIVITY INTO INTERIOR SE
GA DURING THE EVENING HOURS...WHERE ACTIVITY MAY LINGER THROUGH
AROUND MIDNIGHT. OTHERWISE...EXPECTING CONVECTION TO AGAIN BLOSSOM
OVER THE COASTAL WATERS DURING THE OVERNIGHT HOURS DUE TO
DEEPENING SOUTHERLY FLOW. INCREASED MOISTURE AND CLOUD COVER WILL
KEEP LOWS IN THE MID 70S INLAND...AND NEAR 80 AT THE COAST.
.LONG TERM (SATURDAY THROUGH WEDNESDAY)...
FLOW ALOFT WILL TRANSITION TO SOUTHWESTERLY THIS WEEKEND REGION-WIDE
AS WEAK TROUGHING ATTEMPTS TO PUSH INTO THE SOUTHEASTERN STATES...WHICH
WILL SUPPRESS THE AXIS OF ATLANTIC RIDGING TO A POSITION OVER THE FL
PENINSULA. THIS CHANGE IN THE REGIME WILL FOCUS AFTERNOON AND EARLY
EVENING CONVECTION CLOSER TO THE I-95 CORRIDOR...WITH SCATTERED TO
NUMEROUS COVERAGE EXPECTED THIS WEEKEND. OFFSHORE FLOW SHOULD ALLOW FOR
ABOVE NORMAL HIGHS REGION-WIDE...WITH HIGHS CLIMBING INTO THE LOWER 90S
AWAY FROM THE IMMEDIATE COAST...WHERE THE GRADIENT SHOULD REMAIN LOOSE
ENOUGH FOR AN EARLY AFTERNOON SEA BREEZE TO KEEP HIGHS IN THE UPPER 80S.
A RATHER WEAK SURFACE PRESSURE PATTERN WILL PREVAIL FOR THE EARLY AND
MIDDLE PORTIONS OF NEXT WEEK...AND PLENTY OF DEEP-LAYERED MOISTURE WILL
AID IN THE DEVELOPMENT OF AT LEAST SCATTERED DIURNAL CONVECTION...WITH
THE FOCUS SHIFTING BACK TO INLAND LOCATIONS DURING THE AFTERNOON AND
EARLY EVENING HOURS. TEMPERATURES WILL REMAIN ABOVE CLIMO DURING THIS
TIME FRAME.
&&
.AVIATION...PREVAILING VFR TODAY WITH BRIEF PERIOD OF MVFR VSBY
POSSIBLE FOR GNV AND VQQ FROM ABOUT 09Z-11Z. FAVORABLE CONDS FOR
SHOWERS AND STORMS AGAIN TODAY WITH FIRST DEVELOPMENT OF A SHOWER OR
STORM AROUND 16Z-17Z FOR THE COASTAL TAFS. INCLUDED 3 HR TEMPO GROUP
AROUND 17Z-20Z FOR JAX/CRG/VQQ WITH LATER START FOR GNV BY 18Z-19Z.
MVFR CONDS IN STORMS WITH GUSTY WINDS AND SHORT PERIOD OF IFR ALSO
POSSIBLE IN THE STRONGER STORMS. CONVECTION CHANCES DECREASE BY 22Z
OR SO FOR COASTAL TAFS AND AFTER 00Z FOR GNV.
&&
.MARINE...SOUTHEAST TO SOUTH WINDS 10 TO 15 KNOTS WITH SEAS AROUND 2
TO 3 FT. LOCAL SEA BREEZES ALONG THE COAST IN THE AFTERNOONS.
GENERAL FLOW REGIME CHANGE LATE IN THE WEEKEND AS SFC RIDGE
GRADUALLY SHIFTS SWD INTO CENTRAL FL WHILE A WEAK FRONT MOVES INTO
CENTRAL GA...WITH MORE PREVAILING SWLY WINDS SUN.
RIP CURRENTS: MAINLY LOW RISK WITH SMALL SWELLS AROUND 1 TO 1.5 FT
AND SOUTHEAST SEA BREEZES DURING THE DAYTIME HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 93 72 92 71 / 60 30 30 20
SSI 86 76 86 76 / 40 20 20 20
JAX 90 72 90 73 / 50 20 30 20
SGJ 88 74 87 75 / 40 20 30 20
GNV 90 70 91 71 / 60 30 40 30
OCF 90 71 91 72 / 60 30 50 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
SHASHY/NELSON
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
216 AM EDT WED SEP 3 2014
.PREV DISCUSSION... /ISSUED 1029 PM EDT TUE SEP 2 2014/
.UPDATE...
AFTER AN EARLY START TO CONVECTION OVER THE ATLANTA METRO...FOCUS
QUICKLY SHIFTED TO THE SOUTHEAST ZONES WHERE MIDDLE GEORGIA SAW
NUMEROUS STRONG TO SEVERE THUNDERSTORMS. THIS ACTIVITY HAS SENT AN
OUTFLOW NORTHWARD BACK TO THE METRO BUT NEWLY GENERATED ACTIVITY
HAS BEEN HARD TO COME BY. HRRR DOES INDICATE NW ACTIVITY WILL
SPREAD EASTWARD AND INTERACT WITH AFOREMENTIONED OUTFLOW BUT
REMAINS UNCLEAR IF THIS WILL BE ENOUGH TO GENERATE ADDITIONAL
OVERNIGHT THUNDERSTORM ACTIVITY. FOR NOW...HAVE PLAYED IT AS LOW
END CHANCE POPS IN THE GRIDS FOR MOST LOCATIONS...EXCEPT NORTHWEST
WHERE I HAVE GONE SLIGHTLY HIGHER GIVEN ADDED DYNAMICS IN PLAY.
OTHERWISE FORECAST IS IN GOOD SHAPE AND NO CHANGES ARE PLANNED.
DEESE
&&
PREV DISCUSSION... /ISSUED 817 PM EDT TUE SEP 2 2014/
PREV DISCUSSION... /ISSUED 301 PM EDT TUE SEP 2 2014/
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
WEAK IMPULSE IN THE FLOW PUSHING ACROSS THE EASTERN CONUS TODAY AND
THIS MAY HELP THE SHOWERS AND THUNDERSTORMS ACROSS NORTH GEORGIA
CONTINUE INTO TONIGHT. AFTER THIS THOUGH...NO SIGNIFICANT FEATURE AT
THE UPPER LEVELS TO KEY IN ON IN THE SHORT TERM. BASICALLY WILL
CONTINUE AGAIN TOMORROW WITH THE DIURNALLY DRIVEN THUNDERSTORMS IN
THE AFTERNOON AND EVENING. WITH MUCAPE VALUES OVER 2000 J/KG
WEDNESDAY AFTERNOON...STRONG TO ISOLATED SEVERE STORMS WILL BE
POSSIBLE. THE MAIN THREATS TOMORROW AFTERNOON APPEAR TO BE GUSTY
WINDS AND LOCALLY HEAVY RAINFALL.
FAIRLY BIG DISCREPANCIES IN THE TEMPERATURE GUIDANCE FOR TOMORROW
WITH THE MAV BEING WARMER THAN THE MET. AT ATL...THERE IS A SIX
DEGREE TEMPERATURE DIFFERENCE BETWEEN THESE TWO FOR HIGHS TOMORROW
AFTERNOON. MUCH OF THIS IS CAUSED BY MORE CLOUD COVERAGE DEPICTED BY
THE NAM. THINK THE NAM IS OVERDOING CLOUD COVERAGE THOUGH SO STARTED
WITH A BLEND...AND THEN LEANED TOWARDS THE WARMER SIDE FOR HIGH
TEMPS TOMORROW. ONCE AGAIN BOTH HIGH AND LOW TEMPERATURES WILL BE
ABOVE NORMAL.
11
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
NO CHANGES TO THE CURRENT LONG TERM. SEE PREVIOUS DISCUSSION BELOW...
17
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED 325 AM EDT TUE SEP 2 2014/
SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS EXPECTED
EACH DAY THROUGH THE LONG TERM.
WEAK TROUGH STILL IN PLACE ACROSS CENTRAL GA WEDNESDAY NIGHT...BUT
WILL EVENTUALLY DISSIPATE ON THURSDAY. ALOFT...A WEAK SHEAR AXIS
WILL REMAIN THROUGH FRIDAY. THE DISSIPATING BOUNDARY AND SHEAR AXIS
ALOFT MAY SERVE TO FOCUS ANY CONVECTION THURSDAY INTO FRIDAY.
A WEAK FRONT IS STILL ON TRACK FOR THE MID TO LATE WEEKEND. WITH
SUCCESSIVE RUNS...THE MODELS HAVE SLOWED THE SOUTHWARD PROGRESS OF
THE BOUNDARY. CURRENTLY...THE FRONT SHOULD MOVE ACROSS NORTHERN GA
LATE SATURDAY/EARLY SUNDAY THEN STALL ACROSS CENTRAL GA BY LATE
SUNDAY/EARLY MONDAY. THE FRONT LOOKS TO BECOME DIFFUSE BY TUESDAY.
TEMPS STILL EXPECTED TO BE ABOVE NORMAL THROUGH THE PERIOD.
NLISTEMAA
&&
.AVIATION...
06Z UPDATE...
MAINLY VFR CONDITIONS THOUGH CHANCE FOR MORNING MVFR VSBYS AT SOME
SITES. CIGS GENERALLY NEAR 12 KFT THIS MORNING WITH SOME SCT NEAR
5 KFT. AFTERNOON CU FIELD LIKELY IN 4-5 KFT RANGE ALONG WITH
DECENT TSRA POTENTIAL AFTER 18-19Z. WINDS GENERALLY LIGHT AND VRB
TO CALM INITIALLY BECOMING NW TO W UNDER 7 KTS TODAY. VRB GUSTS
AND REDUCED VSBYS AGAIN POSSIBLE WITH ANY STORM DEVELOPMENT.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM IN PRECIP TIMING.
HIGH ALL ELSE.
BAKER
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 95 71 92 69 / 40 30 40 30
ATLANTA 90 73 88 70 / 40 40 40 30
BLAIRSVILLE 86 66 84 63 / 40 30 40 30
CARTERSVILLE 91 69 90 68 / 30 30 40 30
COLUMBUS 94 74 90 71 / 40 40 30 20
GAINESVILLE 90 72 89 69 / 40 30 40 30
MACON 94 71 92 69 / 40 40 30 20
ROME 92 69 91 68 / 30 30 40 30
PEACHTREE CITY 90 70 88 68 / 40 40 40 30
VIDALIA 95 73 92 71 / 40 30 30 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11/DEESE
LONG TERM...NLISTEMAA/17
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
135 AM EDT WED SEP 3 2014
.SYNOPSIS...
ISSUED AT 130 AM EDT TUE SEP 2 2014
WITH HIGH PRESSURE OVER THE REGION...SKIES WILL BE MOSTLY CLEAR
AND LOW TEMPERATURES WILL DROP INTO THE 50S OVERNIGHT. THERE WILL
BE AREAS OF FOG WITH PATCHY DENSE FOG IN LOW LYING AREAS AND NEAR
BODIES OF WATER. ONCE THE FOG BURNS OFF ON WEDNESDAY A BEAUTIFUL
EARLY SEPTEMBER DAY WILL BE IN STORE WITH HIGHS IN THE MIDDLE 80S
ALONG WITH LOWER HUMIDITY.
&&
.UPDATE...
ISSUED AT 656 PM EDT TUE SEP 2 2014
FORECAST STILL ON TRACK NEXT COUPLE OF HOURS AS SEVERAL BOUNDARIES
(OUTFLOW AND LAKE BREEZE) WERE DRIFTING SOUTH ACROSS N INDIANA AND
NW OHIO. ISOLATED SHOWERS HAVE POPPED HERE AND THERE AND EVEN A
STRAY LIGHTNING STRIKE A FEW HOURS AGO. TRENDS SHOULD CONTINUE
DOWNWARD WITH LOSS OF HEATING AND EVENTUAL TRANSLATION OF
BOUNDARIES OUT OF THE AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 344 PM EDT TUE SEP 2 2014
INFILTRATION OF DRIER AIR INTO THE REGION HAS BEEN SLOW THIS
AFTERNOON...WITH AMPLE BOUNDARY LAYER MOISTURE AMID WASHED OUT
SURFACE BOUNDARY ACROSS THE FORECAST AREA. LOW CLOUDS HAVE BEEN SLOW
TO MIX OUT THROUGH EARLY AFTERNOON BUT LATEST SAT TRENDS SHOWING
MORE SCT LOW LVL CLOUD LAYER...ESPECIALLY NW. ISOLD SHOWERS
CURRENTLY NOTED ON RADAR ACROSS NW/NC IN...GIVEN AMPLE BOUNDARY
LAYER MOISTURE...WEAK SFC CONVERGENCE AND SFC HEATING YIELDING VERY
MODEST SB CAPES UP TO 1000 J/KG ACROSS THE REGION. HRRR AND EVEN
NAM12 HINTING AT ISOLD SHOWER ACTIVITY SPREADING EAST ACROSS THE
FORECAST AREA THROUGH SUNSET. THEREFORE HAVE KEPT AN ISOLD SHOWER
MENTION THROUGH 00Z IN THE FCST. LOW CONFIDENCE FOR THUNDER AT THIS
TIME GIVEN LACK OF FORCING AND WEAK MID LVL LAPSE RATES.
AS RIDGING BUILDS EASTWARD INTO THE OVERNIGHT HOURS...CLEARING SKIES
AND DRY CONDITIONS EXPECTED. WITH SLACKENING GRADIENT AND LOW LVL
MOISTURE...ESPECIALLY SE W/ THE PRECIP OVER THE PAST 24 HRS...FOG
DEVELOPMENT LOOKS LIKELY LATE IN THE OVERNIGHT INTO DAYBREAK
WEDNESDAY. KEPT PREVIOUS FCST IN TACT WITH AREAS OF FOG MENTION FROM
09-12Z. LOW CONFIDENCE WITH THE POSSIBILITY OF DENSE FOG AT THIS
TIME...GIVEN LOW LEVEL DRY ADVECTION AND EXTENSIVE CIRRUS SHIELD
NOTED ACROSS THE SOUTHWEST HALF OF THE FORECAST AREA THIS AFTERNOON.
IF CLOUD COVER IS QUICK TO DIMINISH TONIGHT...W/ LACK OF ANY
CONVECTIVE DEBRIS...THEN DENSE FOG CHANCES WOULD INCREASE TOWARD
TOMORROW MORNING...ESPECIALLY SE. WILL MONITOR TRENDS THROUGH THE
EVENING AND WILL UPDATE AS NECESSARY.
RIDGING BUILDS EAST OF THE AREA THROUGH THE DAY ON WEDNESDAY...WITH
MOSTLY SUNNY SKIES AND FAIR CONDITIONS. KEPT HIGH TEMPS SLIGHTLY
BELOW MAV...ALTHOUGH UPWARD ADJUSTMENT MAY BE NEEDED IN THE NEXT
FCST WITH WAA INTO THE AREA BY THE AFTERNOON HOURS ON THE WESTERN
PERIPHERY OF THE RIDGE.
&&
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 344 PM EDT TUE SEP 2 2014
THE GFS AND ECMWF HAVE APPEARED TO INITIALIZE THE UPSTREAM SHORT
WAVE WELL AND ALSO SEEM HAVE A REASONABLE TRACK WITH THIS SYSTEM
ACROSS THE CONUS THIS WEEK. THE ECMWF AND GFS HAVE ALSO SHOWN GOOD
CONSISTENCY FROM RUN TO RUN WITH THIS SYSTEM THE PAST SEVERAL RUNS.
LOW LEVEL THETA E AND MOISTURE FLUX WILL INCREASE RAPIDLY WEDNESDAY
NIGHT...ESPECIALLY NORTH AND NORTHWEST OF THE AREA. HAVE ADDED A
SMALL CHANCE FOR THUNDERSTORMS OVERNIGHT WEDNESDAY NIGHT ON THE
LEADING EDGE OF THIS THETA E ADVECTION OVER FAR NORTHWEST AREAS...
ESPECIALLY BERRIEN AND LAPORTE COUNTY. KEPT THURSDAY DRY AS THE
PRIMARY LOW LEVEL FORCING SHIFTS NORTH OF THE AREA AND AS A LOW
LEVEL INVERSION INCREASES AT THE BASE OF A WEAK TO MODERATE ELEVATED
MIXED LAYER. THE GFS MAV/MEX TEMPERATURES HAVE BEEN CONSISTENT AT
GENERALLY 5 TO 10 DEGREES ABOVE NORMAL FOR THURSDAY AND FRIDAY AND
APPEAR ON TRACK WITH 850 MB TEMPERATURES APPROACHING 20C.
THUNDERSTORM CHANCES LOOK BEST OVERNIGHT THURSDAY NIGHT THROUGH
FRIDAY NIGHT AS A COLD FRONT APPROACHES. GIVEN THE TIMING OF THE
FRONT AND SUBSTANTIAL INSTABILITY BY LATE THURSDAY AND FRIDAY
AFTERNOON/EARLY EVENING WITH CAPES AS HIGH AS 2000 TO 3000
J/KG...CONCERN FOR AN UPSTREAM CONVECTIVE COMPLEX TO DROP SOUTHEAST
OR SOUTH INTO THE FORECAST AREA AS RICH THETA E SPREADS OVER THE
AREA. EXPANDED THUNDERSTORM CHANCES THURSDAY NIGHT IN THIS REGARD.
OTHERWISE...KEPT STORM CHANCES FRIDAY AND FRIDAY NIGHT. OTHERWISE...
COOLER AND DRIER CONDITIONS CAN BE EXPECTED FOR THE WEEKEND INTO
NEXT WEEK WITH HIGHS IN THE 70S THROUGH TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 130 AM EDT WED SEP 3 2014
A WEAK SHORT WAVE PASSING THROUGH THE REGION WAS GENERATING SOME
MID LEVEL CLOUDS. THESE SHOULD BE SHORT LIVED WITH VFR TO START
THE TAF PERIOD. LIGHT WINDS AND MOSTLY CLEAR SKIES WILL ALSO ALLOW
BR TO FORM. HAVE ALREADY SEEN SOME PATCHY MVFR AND IFR IN RURAL
AREAS. STILL EXPECT KFWA TO HAVE BEST CHANCE OF SEEING MVFR AND
IFR CONDITIONS OVERNIGHT. FOG SHOULD BURN OFF QUICKLY AFTER
SUNRISE WITH VFR AND SOUTH TO SOUTHWEST WINDS UNDER 10 KNOTS
EXPECTED REMAINDER OF PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...FISHER
SYNOPSIS...LASHLEY
SHORT TERM...NG
LONG TERM...SKIPPER
AVIATION...LASHLEY
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AREA FORECAST DISCUSSION
NWS DODGE CITY KS
103 AM CDT WED SEP 3 2014
...UPDATED AVIATION SECTION...
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 344 PM CDT TUE SEP 2 2014
THE MID TO UPPER LEVEL FLOW HAS BECOME ZONAL IN THE WAKE OF THE
MINOR SHORTWAVE TROUGH THAT TRAVERSED THE CENTRAL PLAINS MONDAY
EVENING. THE EFFECTIVE FRONTAL BOUNDARY AFTER ALL OF THE NIGHTTIME
CONVECTION WAS SITUATED ACROSS CENTRAL OKLAHOMA AND SOUTHERN
ARKANSAS. SOUTH OF THIS FRONT, TEMPERATURES WERE ABOVE 90 AS OF 2
PM, BUT ON THE COOL SIDE OF THE FRONT, MOST READINGS WERE IN THE
70S TO LOWER 80S. LEE TROUGHING WILL DEVELOP TONIGHT AND
WEDNESDAY IN RESPONSE TO THE ZONAL FLOW. LATE TONIGHT, WARMER MID
LEVEL TEMPERATURES WILL SPREAD ACROSS SOUTHWEST KANSAS, CAPPING
THE ELEVATED MOIST LAYER. THE NAM INDICATES THAT LOW LEVEL WINDS
WILL BECOME SOUTHERLY AS THE WARM FRONT SHIFTS INTO NORTHERN
KANSAS BY WEDNESDAY MORNING. HOWEVER, THE RAP SHOWS THE BOUNDARY
STILL SITUATED ALONG THE KANSAS/OKLAHOMA BORDER AT 12Z. SINCE WE
MAY MAINTAIN UPSLOPE SOUTHEASTERLY FLOW MOST OF THE NIGHT, I OPTED
TO BRING THE LOW CLOUDS AND FOG BACK IN TOWARD 09Z. A MID LEVEL
CLOUD DECK MAY DEVELOP AS THE LOW LEVEL JET DEVELOPS THIS EVENING
AND AN ELEVATED THUNDERSTORM OR TWO CAN`T BE COMPLETELY RULED OUT
OVER SOUTH CENTRAL KANSAS BEFORE THE STRONG CAPPING INVERSION
DEVELOPS.
ON WEDNESDAY, THE LEE TROUGH WILL BECOME ESTABLISHED ACROSS THE
HIGH PLAINS, WITH A WEAK SURFACE DRYLINE SITUATED ACROSS FAR
WESTERN KANSAS. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT
LATE IN THE DAY. HIGH TEMPERATURES WILL BE IN THE MID TO HIGH 90S,WITH
SOME READINGS CLOSE TO 100F.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 357 PM CDT TUE SEP 2 2014
A STRONG UPPER LEVEL SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST
WILL MOVE EASTWARD INTO THE NORTHERN PLAINS AND UPPER MIDWEST BY
FRIDAY. THIS SYSTEM WILL PUSH A COLD FRONT ACROSS WESTERN KANSAS AND
THE CENTRAL PLAINS ON THURSDAY BRINGING THE BEST CHANCES FOR SHOWERS
AND THUNDERSTORMS. THE STRONGEST MID AND UPPER LEVEL WINDS WILL BE
IN NEBRASKA, SO NOT EXPECTING LOTS OF SEVERE WITH THE FRONT. CAPE
VALUES AROUND 2000 J/KG WILL BE SUFFICIENT TO PRODUCE SOME SMALL
HAIL AND STRONG WINDS AS THE COLD FRONT SWEEPS ACROSS WESTERN KANSAS
TO NEAR DODGE CITY BY 7 PM THURSDAY AND THROUGH MEDICINE LODGE BY
AROUND MIDNIGHT.
HIGH TEMPERATURES WILL BE VERY WARM AHEAD OF THE COLD FRONT ON
THURSDAY WITH LOW TO MID AND UPPER 90S FORECAST. HIGHS THEN COOL
INTO THE 70S INTO FRIDAY WITH A CONTINUED CHANCE FOR MAINLY
AFTERNOON THUNDERSTORMS BEHIND THE FRONT IN MOIST SURFACE UPSLOPE
FLOW.
BY MONDAY HIGHS WARM BACK INTO THE 80S AS THE COOL HIGH PRESSURE
AREA MOVES EAST AND WARM SOUTHERLY WINDS INCREASE. MORE THUNDERSTORM
CHANCES CONTINUE INTO TUESDAY WITH DISTURBANCES IN SOUTHWEST FLOW
ALOFT AND UPPER JET.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1259 AM CDT WED SEP 3 2014
THE AVIATION FORECAST THROUGH 12-15Z TIME FRAME WEDNESDAY WILL BE
CHALLENGING. WE WILL MAINTAIN THE PESSIMISTIC FORECAST OF CEILING
FALLING TO AROUND 200-300 FEET AT GCK AND DDC STARTING AROUND 10Z.
THE LIFR CONDITIONS SHOULD EXIST FOR AT LEAST A COUPLE HOURS
BEFORE DRIER AIR MOVES IN FROM THE SOUTHWEST AS LOW LEVEL
SOUTHWEST MOMENTUM INCREASES BY DAYBREAK. FOR NOW, WE WILL KEEP
HYS AWAY FROM THE IFR/LIFR CONDITIONS, BUT THIS IS ALSO A LOW
CONFIDENCE FORECAST WITH AMENDMENTS QUITE POSSIBLE. SOUTHWEST
WINDS WILL INCREASE DURING THE LATE MORNING THROUGH MIDDAY TIME
FRAME, GUSTING TO 30+ KNOTS BY AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 72 95 64 78 / 0 10 40 40
GCK 70 92 61 76 / 0 20 40 40
EHA 68 94 63 79 / 10 10 60 30
LBL 71 96 66 81 / 10 0 40 40
HYS 72 92 61 72 / 10 20 50 40
P28 74 97 70 83 / 10 0 30 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...KRUSE
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS JACKSON KY
151 AM EDT WED SEP 3 2014
.UPDATE...
ISSUED AT 1020 PM EDT TUE SEP 2 2014
01Z SFC ANALYSIS SHOWS WAKE HIGH PRESSURE OVER MUCH OF EAST KENTUCKY
TRAILING THE LINEAR MCS THAT PASSED THROUGH DURING THE EVENING WITH
STRONG TO SEVERE STORMS THAT PRODUCED MAINLY DAMAGING WIND GUSTS.
THIS SYSTEM HAS ESSENTIALLY WASHED OUT THE FRONT AND PUSHED IT MAINLY
SOUTH AND EAST OF KENTUCKY. HOWEVER...THERE WILL STILL BE SOME
SCATTERED SHOWERS AND PERHAPS A STRAY STORM AROUND THE FAR SOUTHEAST
PORTION OF THE CWA INTO THE NIGHT. THE CLOUDS WILL GRADUALLY THIN AND
CLEAR OVERNIGHT AND THIS WILL LIKELY SET THE STAGE FOR FOG
FORMATION...BECOMING LOCALLY DENSE IN THE VALLEYS BY DAWN. HAVE
INCLUDED THIS ALL IN THE GRIDS WITH THIS UPDATE. ALSO FINE TUNED THE
TEMPS AND DEW POINTS THROUGH MORNING PER THE LATEST OBS...TRENDS...AND
GUIDANCE FROM THE CONSSHORT. THESE HAVE BEEN SENT TO THE NDFD AND WEB
SERVERS. A FRESHENED SET OF ZONES AND HWO HAVE BEEN SENT.
UPDATE ISSUED AT 758 PM EDT TUE SEP 2 2014
THE MAIN LINE OF STORMS IS FINALLY MOVING INTO THE NEIGHBORING
STATES. A SECONDARY TROUGH IS MOVING THROUGH THE BLUEGRASS AND
APPEARS TO BE FALLING APART. THIS SYSTEM WILL CONTINUE TO MOVE TO THE
SOUTH AND EAST AND WILL BE OUT OF THE AREA BY MORNING. HAD TO LOWER
THE TEMPERATURES AS THEY DROPPED DOWN MUCH LOWER THAN EXPECTED AS THE
LINE WENT THROUGH THE AREA. EXPECT FOG TO BE FORMING AS THE SYSTEM
MOVES OUT. IT WILL BE PATCHY...BUT MAINLY DENSE. SOME ISOLATED
SHOWERS MAY DEVELOP BEHIND THE MAIN SYSTEM TONIGHT...SO DID NOT
IMMEDIATELY END THE PRECIPITATION CHANCES. THE REST OF THE FORECAST
IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 343 PM EDT TUE SEP 2 2014
A LINE OF THUNDERSTORMS WITH HEAVY RAINS HAS FORMED ALONG AN OLD
OUTFLOW BOUNDARY ACROSS THE MID SECTION OF EASTERN KENTUCKY. SOME OF
THE STORMS HAVE BECOME NEAR SEVERE AND EXPECT SOME SEVERE STORM
WARNINGS TO BE ISSUED DURING THE NEXT FEW HOURS. THE MAIN THREAT
WILL BE WIND GUSTS. ANOTHER CONCERN IS THAT WITH UNIDIRECTIONAL FLOW
AND HIGH PRECIPITABLE WATER...FLOODING CONCERNS WILL BE A REAL ISSUE
THIS AFTERNOON AND EVENING...MAINLY IN THE SOUTHERN HALF OF EASTERN
KENTUCKY AND ESPECIALLY ALONG THE OLD OUTFLOW BOUNDARY. EXPECT THE
FRONT TO PUSH THE PRECIPITATION SOUTH OF THE AREA BY WEDNESDAY
MORNING. IN GENERAL...THE HRRR AND RAP HAVE NOT BEEN DOING TOO WELL
WITH THIS SYSTEM SO FAR. WEDNESDAY FIGURES TO BE A LITTLE MORE
COMFORTABLE AS THE HUMIDITY WILL BE A LITTLE LOWER.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 301 PM EDT TUE SEP 2 2014
THE MODELS BEGIN THE EXTENDED PERIOD IN PRETTY GOOD AGREEMENT ONCE
AGAIN...WITH A RIDGE OF HIGH PRESSURE...BOTH ALOFT AND AT THE
SURFACE...CENTERED OVER THE EASTERN GULF OF MEXICO...ALONG WITH A
WELL DEFINED TROUGH OF LOW PRESSURE ALOFT TAKING SHAPE OVER THE
NORTHERN PLAINS. THE MODELS HAVE THE RIDGE STEADILY BREAKING DOWN
TO BEGIN THE PERIOD...WITH SHOWERS AND STORMS POPPING UP BENEATH IT
ACROSS THE TENNESSEE VALLEY DOWN TO THE GULF AND ACROSS PORTIONS OF
THE SOUTHEASTERN CONUS. AS THE TROUGH EVOLVES AND STRENGTHENS...IT
WILL EJECT OUT OF THE PLAINS WEDNESDAY AND THURSDAY...AND PUSH
ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS. THE COLD FRONT
TRAILING FROM THIS UPPER LOW WILL END UP BEING OUR WEATHER MAKER FOR
THE UPCOMING WEEKEND. THE FRONT IS EXPECTED TO INTERACT WITH
MOISTURE COMING OFF THE GULF OF MEXICO ON SOUTHWESTERLY WINDS. THE
FRONT WILL HAVE A DIFFICULT TIME MOVING EASTWARD...HOWEVER...AS THE
RIDGE DIGS IN A BIT JUST OFF THE SOUTHEAST COAST AND FLOW ALOFT
BECOMES MORE ZONAL. THERE WILL BE A GOOD CHANCE OF RAIN FRIDAY
MORNING THROUGH SUNDAY MORNING...AS LIFT AND MOISTURE ALONG THE
SLUGGISH FRONT SET OFF REPEATED ROUNDS OF SHOWERS AND STORMS. THE
RAIN SHOULD FINALLY MOVE OUT OF THE AREA SUNDAY EVENING...AS THE
FRONT FINALLY MOVES OUT OF THE AREA.
TEMPERATURES TO BEGIN THE PERIOD LOOK TO BE ABOVE NORMAL...WITH
HIGHS TOPPING OUT AROUND IN THE MID TO UPPER 80S THURSDAY AND
FRIDAY. ONCE THE FRONT STALLS ACROSS THE AREA AND PRECIPITATION
BECOMES MORE WIDESPREAD...TEMPERATURES WILL LIKELY MAX OUT BELOW
NORMAL VALUES SATURDAY THROUGH MONDAY. THE POSITIONING OF THE FRONT
OVER THE WEEKEND WILL ALLOW FOR SOME COOLER AND DRIER AIR TO FILTER
INTO THE AREA. HIGHS ON SATURDAY SHOULD BE JUST BELOW NORMAL...AS
THE BULK OF COOL AIR SHOULD STILL BE TRAPPED NORTH OF THE OHIO
RIVER. ON SUNDAY...HOWEVER...ONCE WINDS HAVE SHIFTED TO THE
NORTH...TEMPERATURES WILL BE QUITE COOL...WITH READINGS PEAKING IN
THE MID TO UPPER 70S FOR MOST LOCATIONS. THE NORTHERLY FLOW WILL
ONLY ALLOW FOR A SMALL WARM UP ON MONDAY...AS HIGHS THAT DAY WILL
LIKELY ONLY TOP OUT IN THE UPPER 70S AND LOWER 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 151 AM EDT WED SEP 3 2014
CONDITIONS VARIED WIDELY AT TAF ISSUANCE FROM VLIFR TO VFR. AS
MID/HIGH CLOUDS DECREASE DURING THE NIGHT...WILL EXPECT FOG AND LOW
CLOUDS TO BECOME MORE EXTENSIVE...WITH MOST PLACES SETTLING TO IFR OR
WORSE BY DAWN. SLOW IMPROVEMENT IS FORECAST DURING THE DAY ON
WEDNESDAY...WITH VFR FINALLY RETURNING DURING THE AFTERNOON.
SCATTERED SHOWERS SHOULD ALSO DEVELOP IN THE AFTERNOON...MAINLY NEAR
AND SOUTH OF A LINE FROM SOMERSET TO PIKEVILLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...JJ
LONG TERM...AR
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS HASTINGS NE
418 AM CDT WED SEP 3 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM CDT WED SEP 3 2014
UPPER AIR AND SATELLITE DATA SHOWING THE AREA CONTINUING TO BE
INFLUENCED BY ZONAL FLOW...AS HIGH PRESSURE EXTENDS ACROSS THE SRN
CONUS AND BROAD TROUGHING IS IN PLACE NEAR/NORTH OF THE CANADIAN
BORDER...THOUGH AN AREA OF LOW PRESSURE IS PUSHING ITS WAY FURTHER
INLAND FROM THE PAC NW COAST. AS WAS SHOWN BY MODELS...CONVECTION
DEVELOPED EARLIER ACROSS CENTRAL KANSAS...IN RESPONSE TO A WEAK
DISTURBANCE AS WELL AS INCREASED LIFT VIA WARM AIR/MOISTURE
ADVECTION ASSOCIATED WITH A STRONGER LLJ. EARLY ON THE FAR
SOUTHEASTERN CORNER OF MITCHELL COUNTY WAS CLIPPED BY THIS
ACTIVITY...BUT SINCE THEN HAS REMAINED OVER ERN KS. THERE IS A
COUPLE ISOLATED SHOWERS OVER WESTERN KS...AND THE HRRR/RAP HINT AT
SOME ADDITIONAL ACTIVITY POSSIBLY LINGERING INTO THE MID MORNING
HOURS...SO WILL HAVE TO MONITOR HOW THIS ACTIVITY EVOLVES OVER
NEXT FEW HOURS. SATELLITE IMAGERY ALSO SHOWING SOME LOW/MID LEVEL
STRATUS STARTING TO INCREASE IN COVERAGE...BUT MODELS DIFFER SOME
ON HOW EXPANSIVE IT WILL END UP BEING. AT THE SURFACE...THE CWA IS
SET UP BETWEEN HIGH PRESSURE AFFECTING MUCH OF THE ERN CONUS...AND
A TROUGH OF LOW PRESSURE OVER THE HIGH PLAINS. WINDS REMAIN
SOUTHERLY...WITH SPEEDS RANGING FROM 5 TO 15 MPH. TEMPS ARE MORE
MILD THAN 24 HRS AGO...WITH 3 AM TEMPS IN THE MID 60S TO LOWER
70S.
THE MAIN STORY IN THE SHORT TERM PERIOD LIES WITH
TEMPERATURES...AS TODAY IS EXPECTED TO BE THE WARMEST OVER THE
NEXT 7. IN THE UPPER LEVELS...MODELS IN GOOD AGREEMENT SHOWING THE
FLOW TRANSITIONING TO MORE SOUTHWESTERLY AS THAT ABOVE MENTION PAC
NW DISTURBANCE SHIFTS FURTHER EASTWARD INTO THE NRN ROCKIES. WHILE
NOT EXPECTING MUCH IN THE WAY OF PRECIP CHANCES THROUGH TONIGHT
/THOUGH CHANCES ARE NOT ZERO/...THIS PATTERN WILL HELP TO CONTINUE
THE ADVECTION OF WARMER AIR ALOFT INTO THE REGION. THIS WILL
CONTINUE RIGHT ON INTO THE OVERNIGHT HOURS AS THE ASSOCIATED SFC
COLD FRONT CREEPS IN FROM THE WEST. BY SUNRISE THURS...MODEL
TIMING ISNT BAD...SHOWING THE FRONT DRAPED ACROSS THE NWRN CORNER
OF THE CWA.
TEMPERATURES FOR TODAY ARE A LITTLE TRICKY...AS SOME MODELS
SHOWING POOLING OF MOISTURE/HIGHER DPTS IN THE SOMEWHAT USUAL
PLACES FOR OUR CWA...ROUGHLY THE NERN THIRD OR SO...WITH DPTS IN
THE LOWER 70S. THOSE HIGHER DPTS MAY KEEP TEMPS DOWN A TOUCH IN
THOSE AREAS...AND HAVE FORECAST HIGHS RIGHT AROUND 90. FURTHER
SW...THINKING THAT TEMPS WILL REACH INTO THE MID/UPPER 90S WITH
DPTS IN THE LOWER 60S. NOT BUYING INTO THE RAP WHICH IS SHOWING
LOW/MID 50S BY MID AFTERNOON DOWN THERE...WITH TEMPS THEN CLIMBING
INTO THE LOW 100S. SOMETHING FOR THE DAY SHIFT TO WATCH THOUGH. AS
WE GET INTO TONIGHT...WITH THE CONTINUED SOUTHERLY FLOW EXPECTED
THROUGH THE MAJORITY OF THE NIGHT...OVERNIGHT LOWS LOOK TO REMAIN
MILD IN THE MID 60S TO MID 70S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 417 AM CDT WED SEP 3 2014
MAIN ISSUE WILL BE POTENTIAL FOR PRECIPITATION.
WE BEGIN THE LONG TERM ON THURSDAY UNDER UPPER LEVEL SOUTHWEST
FLOW WITH A SUBTROPICAL HIGH IN THE SOUTHEASTERN UNITED STATES.
AND A POSITIVELY TILTED TROUGH OVER THE NORTHWESTERN UNITED
STATES.
MOST IF NOT ALL OF THURSDAY SHOULD BE DRY...DESPITE A SURFACE COLD
FRONT MAKING ITS WAY SLOWLY SOUTH AS NUMERICAL MODELS CONTINUE
TO SHOW POST-FRONTAL PRECIPITATION DEVELOPING MAINLY THURSDAY
EVENING CLOSER TO THE VICINITY OF THE UPPER LEVEL JET
STREAK...WHICH WILL NUDGE SOUTH OVER TIME...AND IN TURN PUSHING
THE COLD FRONT FARTHER SOUTH.
INSTABILITY EVENTUALLY WANES AND THERE WILL BE LESS OF A
THUNDERSTORM CHANCE HEADING INTO FRIDAY AND TOOK OUT THUNDER BY
LATE EVENING FRIDAY NIGHT INTO SATURDAY.
THE FRONT IS STILL EXPECTED TO MAKE A RETURN AS THE SURFACE HIGH
THAT HELPED PUSH THE COLD FRONT SOUTH...MAKES A FAIRLY QUICK
RETREAT TO THE EAST...ALLOWING THE FRONT TO RETURN NORTH AS A
WARM FRONT.
ANOTHER COLD FRONT TUESDAY AFTERNOON/NIGHT WILL BRING IN SOME
COOLER WEATHER FOR WEDNESDAY.
THERE COULD BE ENOUGH OF A COMBINATION OF SHEAR AND INSTABILITY
FOR STRONG TO SEVERE THUNDERSTORMS ANYWHERE FROM SUNDAY NIGHT
INTO TUESDAY...BUT IT WOULD BE A TOUGH CALL TO NAIL ANYTHING DOWN
RIGHT NOW.
FOR TEMPERATURES...I WENT WITH CONSRAW FOR LOWS THURSDAY NIGHT AND
FRIDAY NIGHT. NAM FOR HIGHS THURSDAY AND BCCONSRAW FOR HIGHS
FRIDAY...WHICH ARE CONSIDERABLY COOLER. IN FACT...FRIDAY SHOULD
FEEL RATHER FALL-LIKE. OTHER NUMERICAL MODEL SOLUTIONS HAVE NOT
CAUGHT ON LIKE THE BCCONSRAW HAS...BUT I STRONGLY SUSPECT THAT
THEY WILL SOON...CONSIDERING THE TRACK RECORD OF THIS SOLUTION THE
DAY AFTER A COLD FRONT PASSAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1224 AM CDT WED SEP 3 2014
PRIMARY CONCERN FOR THIS TAF PERIOD COMES THROUGH THE AT LEAST
MIDMORNING...WITH MODELS STILL SHOWING THE POTENTIAL FOR
FOG/STRATUS DEVELOPMENT AS MOISTURE CONTINUES TO ADVECT INTO THE
AREA FROM THE SOUTH. IF MODEL TRENDS PAN OUT...CONDITIONS SHOULD
IMPROVE AS WE GET TOWARD MIDDAY...WITH VFR CONDITIONS FOLLOWING.
NO NOTABLE CHANGES IN WINDS ARE EXPECTED...REMAINING
SOUTHERLY...THOUGH WILL BECOME MORE GUSTY THIS AFTERNOON. SPEEDS
OF 15 TO 20 MPH AND GUSTS NEAR 25 MPH ARE EXPECTED.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...ADO
LONG TERM...HEINLEIN
AVIATION...ADO
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
126 AM EDT WED SEP 3 2014
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL PUSH ACROSS THE NORTH COUNTRY
THROUGH THE EVENING HOURS AHEAD OF A COLD FRONT. EXPECT LOCALLY
HEAVY DOWNPOURS AND GUSTY WINDS WITH THE STRONGER STORMS. SUNNY,
DRY AND COOLER WEATHER WILL LAST INTO THURSDAY. WARM SUMMER WEATHER
RETURNS FRIDAY BUT WILL BE SHORT LIVED AS ANOTHER COLD FRONT SWEEPS IN
EARLY SATURDAY GIVING A TASTE OF FALL-LIKE WEATHER FOR SUNDAY AND
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
AS OF 1044 PM EDT TUESDAY...COLD FRONT CONTINUES TO MAKE ITS WAY
EASTWARD ACROSS VERMONT LATE THIS EVENING...AND WILL EXIT THE
FORECAST AREA BETWEEN 05Z-06Z. HEAVIEST PRECIPITATION WITH SOME
EMBEDDED THUNDER ALONG THE COLD FRONT...WITH POST FRONTAL RAINS
ACROSS REST OF VERMONT AND NORTHEAST NEW YORK ASSOCIATED WITH
TRAILING MID LEVEL SHORTWAVE. MAIN THREAT THIS EVENING HAS BEEN HEAVY
RAINFALL. HOWEVER...RAINFALL RATES IN HEAVIER PRECIPITATION HAVE
DECREASED ENOUGH SO THAT THREAT OF FLASH FLOODING HAS DIMINISHED.
HAVE MADE SOME MINOR ADJUSTMENTS TO FORECAST WITH LATEST UPDATE TO
ACCOUNT FOR LATEST OBSERVATIONAL DATA AND TRENDS.
EARLIER DISCUSSION...
WELL, THE ATMOSPHERE IS FAIRLY PRIMED. VERY WARM AND HUMID
AIRMASS IS RESULTING IN MODEST SURFACE BASED INSTABILITY (CAPE
PUSHING 2000 J/KG AND LIFTED INDEX OF -2 TO -4C). SO FAR THE
ACTIVITY HAS BEEN SPARSE ACROSS THE FORECAST AREA, HOWEVER RADAR
SHOWS THE BUILDING LINE OF SHOWERS AND THUNDERSTORMS OUT ACROSS
ONTARIO. THESE STORMS SHOULD BE CROSSING INTO THE UNITED STATES IN
THE NEXT COUPLE OF HOURS. STILL LIKE HOW THE HRRR AND OUR LOCAL
6KM WRF ARE HANDLING THE EVOLUTION OF THE CONVECTION. STILL LOOKS
LIKE AN ETA INTO THE CHAMPLAIN VALLEY DURING THE EVENING (LET`S GO
WITH 6-8PM) AND THEN INTO EASTERN VERMONT BY 10PM. UPPER LEVEL
SHORTWAVE WHICH IS THE PRIMARY TRIGGER FOR THE CONVECTION IS NOW
OVER MICHIGAN AND STARTING TO LIFT NORTHEAST. OUT AHEAD OF THAT
SHORT WAVE THE WIND FIELDS AND RELATED SHEAR INCREASE, BUT AT THE
SAME TIME WE ARE GETTING CLOSER TO SUNSET AND LOSS OF HEATING. SO
IT`S A BATTLE BETWEEN TIMING OF THE BEST DYNAMICS VS BEST
INSTABILITY.
AT THIS POINT STILL SEE NOTHING TO CHANGE THE IDEA THAT WE`LL HAVE
AT LEAST A FEW STRONG T-STORMS AROUND, ESPECIALLY THIS EVENING AND
MAINLY WEST OF THE GREEN MOUNTAINS. HAVE MAINTAINED THE IDEA OF
GUSTY WINDS AND HEAVY RAIN AS THE PRIMARY THREATS.
THE ACTIVITY WINDS DOWN BY MID EVENING IN THE ST LAWRENCE VALLEY
TO JUST AFTER MIDNIGHT IN EASTERN VERMONT. DEPENDING ON HOW MUCH
CLEARING WE GET, WE COULD HAVE A BIT OF PATCHY FOG LATE TONIGHT.
THE COOLER AIR LAGS THE WEATHER A BIT, SO IT WILL STILL BE A MUGGY
NIGHT WITH LOWS IN THE 60S.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH THURSDAY NIGHT/...
AS OF 355 PM EDT TUESDAY...IT WILL BE A QUIET 48 HOURS. SHORT TERM
MODELS IN PRETTY GOOD AGREEMENT WITH REGARD TO RIDGING OVER THE REGION.
DAILY SPECIFICS...
WEDNESDAY: FLOW TURNS NORTHWEST DURING THE MORNING. 850MB
TEMPERATURES FALL TO 11-12C WHICH WILL SUPPORT HIGH TEMPERATURES
IN THE MID-UPPER 70S. WITH SOME WEAK COLD-AIR ADVECTION AND A GOOD
DEAL OF SUN, WE`LL HAVE SOME EXCELLENT MIXING DURING THE
AFTERNOON. WE SHOULD BE ABLE TO TAP SOME OF THE 20KT OR SO OF WIND
THAT WILL BE A FEW THOUSAND FEET UP, SO IT SHOULD GET A LITTLE
BREEZY IN THE AFTERNOON.
WEDNESDAY NIGHT: HIGH PRESSURE OVERHEAD. CLEAR AND CALM, SO PATCHY
FOG LOOKS LIKE A GOOD BET, ESPECIALLY SINCE THE GROUND WILL STILL
BE A BIT DAMP FROM THE RAIN THIS EVENING. TEMPERATURES MAINLY IN
THE 50S, THOUGH UPPER 40S POSSIBLE IN COLD SPOTS LIKE SARANAC LAKE.
THURSDAY: SHORTWAVE RIDGING AND SURFACE HIGH PRESSURE STILL NEARLY
OVERHEAD, BUT STARTING TO PUSH EAST OF THE AREA. 850MB
TEMPERATURES UP TO 12-13C, WHICH SUPPORTS UPPER 70S TO LOW 80S FOR
HIGHS. PLENTY OF SUN AS WELL.
THURSDAY NIGHT: DISCARDED THE NAM AS IT SEEMS TOO AGRESSIVE WITH
THE LEADING EDGE OF WARM AIR ADVECTION AND PRODUCES THICKENING
CLOUDS AND EVEN SOME LIGHT SHOWERS. THINK IT WILL REMAIN MOSTLY
CLEAR AND DRY PER OTHER MODELS. HOWEVER WITH SOUTHWEST FLOW
DEVELOPING, IT WON`T BE AS COLD, LOTS OF 50S AND EVEN LOW 60S FOR
LOWS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 350 PM EDT TUESDAY...EXTENDED PERIOD REMAINS PREDOMINATELY
QUIET...LARGELY DOMINATED BY HIGH PRESSURE STARTING THE LATTER
PART OF THE WEEKEND...BUT WET TO BEGIN. FOR THE START OF THE
PERIOD...RISING HEIGHTS AND WARMING TEMPERATURES CONTINUE FRIDAY
AS AN UPPER RIDGE CRESTS OVER THE NORTHEAST IN ADVANCE OF OUR NEXT
SURFACE FRONT. MEAN 925MB TEMPS OF +20-23C WILL SUPPORT HIGHS WELL
ABOVE NORMAL FOR EARLY SEPTEMBER WITH WIDESPREAD 80`S EXPECTED.
IT`LL BE MUGGY TOO WITH DEWPOINTS RANGING THROUGH THE 60S WHICH
WILL CREATE AMPLE SURFACE INSTABILITY TO SUPPORT SHOWER AND
THUNDERSTORM DEVELOPMENT ALONG/AHEAD OF THE AFOREMENTIONED FRONT
WHICH WILL SHIFT INTO THE BTV CWA LATE IN THE DAY AND THROUGH THE
EVENING. STILL LOOKS LIKE THE BEST UPPER DYNAMICS PASSES TO OUR
NORTH...WITH THE SURFACE BOUNDARY PARALLEL WITH UPPER FLOW
SUPPORTING THE IDEA OF A SLOW EASTWARD PROGRESSION WHICH IS
MAINTAINED BY THE LATEST ECMWF. GFS REMAINS A BIT FASTER PUSHING
THE BOUNDARY THROUGH THE CWA BY SATURDAY MORNING SO HAVE CONTINUED
ON WITH THE PREVIOUS FORECAST THINKING LEANING TOWARDS THE ECMWF.
BY LATE SATURDAY TREND WILL BE TOWARDS CLEARER AND DRIER WEATHER AS
THE UPPER FLOW TURNS ZONAL AND SURFACE HIGH PRESSURE BUILDS
EASTWARD OUT OF THE CENTRAL CONUS. THIS HIGH THEN SLOWLY SHIFTS EAST
THROUGH THE NORTHEAST AND OFF INTO THE CANADIAN MARITIMES BY LATE
TUESDAY OFFERING A NICE STRETCH OF LATE SUMMER WEATHER. TEMPS RETURN
TO MORE SEASONABLE LEVELS TO MAYBE SLIGHTLY BELOW NORMAL WITH
EXPECTED HIGHS SATURDAY THROUGH TUESDAY IN THE UPPER 60S TO LOW
70S...AND LOWS IN THE MID 40S TO LOW 50S.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 06Z THURSDAY...BULK OF THE RAINFALL HAS MOVED EAST OUT OF
VERMONT AND ALL TAF SITES FORECASTS ARE RAIN FREE. LIFR CEILINGS
AT KMSS KSLK KMPV EXPECTED TO CONTINUE OVERNIGHT. VFR CIGS ELSEWHERE
THROUGH 12Z THEN CONDITIONS IMPROVE TO VFR CLR. QUITE A BIT OF
VARIABILITY WITH CLOUD COVER ACROSS THE AREA...AND EXPECT TO BE
CHASING OBS WITH AMENDMENTS THROUGH MORNING HOURS AS CIGS VARY UP
AND DOWN IN THE LIFR LOCATIONS. DID NOT HIT VIS TOO HARD DESPITE
OVERNIGHT RAINFALL...THINKING CLOUD COVER WILL INHIBIT RADIATIONAL
COOLING AND FOG FORMATION. LIGHT WEST TO NW WIND THROUGH THE
FORECAST PERIOD.
OUTLOOK 00Z THURSDAY THROUGH SUNDAY...
06Z THU - 00Z SAT...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR
FOG POSSIBLE...ESPECIALLY AT KMPV/KSLK.
00Z SAT - 00Z SUN...POSSIBLE MVFR AND BRIEF IFR IN SCATTERED SHOWERS
AND THUNDERSTORMS.
00Z SUN - 00Z MON...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR FOG
POSSIBLE...ESPECIALLY AT KMPV/KSLK.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...NASH
NEAR TERM...RJS/NASH
SHORT TERM...NASH
LONG TERM...LAHIFF
AVIATION...HANSON
AREA FORECAST DISCUSSION
NWS RALEIGH NC
330 AM EDT WED SEP 3 2014
.SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS
CENTRAL NC TODAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR
THE REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 305 AM WEDNESDAY...
A FEW SHOWERS POPPING UP ALONG REMNANT OUTFLOW FROM CONVECTION
CROSSING THE MOUNTAINS LATE LAST EVENING WILL CONTINUE TO MOVE OFF
TO THE NORTHEAST ACROSS THE NORTHERN PIEDMONT THIS MORNING.
LINGERING INSTABILITY AND RECENT RADAR TRENDS SUGGEST THAT A COUPLE
ISOLATED THUNDERSTORMS ARE POSSIBLE AS WELL. THE OUTLFOW WILL
SETTLE SOUTH THIS MORNING AND SHOULD PRETTY MUCH BISECT THE AREA
FROM SOUTHWEST TO NORTHEAST BASED ON THE LATEST RAP FORECAST. THERE
IS NO REAL AIRMASS CHANGE ACROSS THE AREA AND THE BLENDED TOTAL PW
PRODUCT SHOWS PW VALUES OF 1.8 TO 2 INCHES HIS MORNING. H85 TEMPS
ARE DOWN A COUPLE DEGREES FROM THE LATEST COUPLE OF DAYS AND HIGHS
SHOULD ONLY BE IN THE LOW TO MID 90S TODAY. HOWEVER..THE STRONG
HEATING COMBINED WITH THE MOIST AIRMASS WILL LEAD TO MODERATE
INSTABILITY AGAIN THIS AFTERNOON. LOW-LEVEL CONVERGENCE AND A
REMNANT DISTURBANCE/SHEAR AXIS ALOFT WILL SERVE AS A TRIGGER FOR
SCATTERED TO SOMETIMES NUMEROUS SHOWERS AND STORMS...AND WHILE
MOISTURE/INSTABILITY SHOULD FAVOR BETTER COVERAGE ACROSS THE
SOUTH...WEAK STEERING FLOW AND PROPAGATING OUTFLOWS MAKES IT
DIFFICULT TO ASSESS WHERE STORM COVERAGE WILL BE THE GREATEST. MOST
HIRES GUIDANCE SHOWS STORMS DEVELOPING ACROSS THE SOUTH BY 19Z AND
THEN SHIFTING NORTHWARD AS THE AFOREMENTIONED BOUNDARY WASHES OUT.
HEAVY RAIN...MINOR FLOODING AND A FEW STRONG WIND GUSTS WILL BE THE
MAIN STORM THREATS.
CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE
COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO
SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER
60S AND LOWER 70S.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 305 AM WEDNESDAY...
THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A
SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS
HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE
AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION
SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR
SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED
COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL
THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH
NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL
INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN
THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 330 AM WEDNESDAY...
THE SUB-TROPICAL RIDGE WILL BRIEFLY EXPAND NORTH INTO THE OH VALLEY
AND MIDDLE ATLANTIC...AND CONSEQUENTLY CAUSE THE MID LEVEL SHEAR AND
MOIST AXIS SETTLING INTO CENTRAL NC THIS MORNING...TO WEAKEN AND BOW
NORTH INTO VA FRI-SAT. MEDIUM RANGE ENSEMBLE GUIDANCE SUGGESTS THE
SUB-TROPICAL RIDGE WILL THEN WEAKEN AND BECOME SUPPRESSED...BY A
PAIR OF SHORTWAVE TROUGHS FORECAST TO CROSS THE NE US AND SE CANADA
IN PROGRESSIVE FLOW ALOFT THROUGH THE END OF THE WEEKEND. GUIDANCE
IS ALSO IN AGREEMENT THAT SOME DEGREE OF TROUGHING WILL BE LEFT
BEHIND IN A POSITIVE TILT FASHION OVER THE MIDDLE ATLANTIC...THOUGH
THE DEGREE OF WHICH REMAINS UNCERTAIN DUE TO ABOVE AVERAGE MODEL
SPREAD OF THE H5 PATTERN BY DAYS 6-7 (MON-TUE). THE EBB AND FLOW OF
THE PATTERN ALOFT...AND ASSOCIATED SUPPRESSION OF THE SUB-TROPICAL
RIDGE...WILL ALLOW THE POLAR FRONT TO SETTLE SE THROUGH CENTRAL NC
CENTERED AROUND THE DAY SUNDAY...BEFORE SLOWING AS IT DRIFTS
OFFSHORE AND INTO THE VICINITY OF THE GULF STREAM THROUGH MID-WEEK.
A WEAK WAVE OF LOW PRESSURE...OR TWO...ARE APT TO DEVELOP ALONG THE
SLOWING FRONT...AS THE AFOREMENTIONED POSITIVELY TILTED TROUGH ALOFT
INTERACTS WITH SEASONABLY STRONG BAROCLINICITY DRIVEN BY THE
INCOMING COOL/DRY CANADIAN AIR MASS INTO THE WARM/MOIST GULF STREAM
WATERS.
FRI-SAT: A PATTERN OF WEAK SYNOPTIC-SCALE ASCENT AHEAD OF THE
AFOREMENTIONED POLAR FRONT WILL FAVOR NEAR CLIMO PROBABILITIES OF
DIURNALLY-DRIVEN CONVECTION ALONG THE SEA BREEZE AND MOUNTAINS...
BOTH OF WHICH WILL BE APT TO PROPAGATE INTO THE WESTERN AND EASTERN
EDGES OF THE RAH CWFA EACH AFTERNOON AND EVENING. THE DISSIPATION
AND NORTHWARD DEPARTURE OF MID-HIGH CLOUDINESS ASSOCIATED WITH THE
AFOREMENTIONED SHEAR AXIS ALOFT...RESULTING FROM THE BRIEFLY
BUILDING SUB-TROPICAL RIDGE...SHOULD ALLOW FULL-SUN (OR NEARLY SO)
H85 TEMPS IN THE 17-18C RANGE TO BE REALIZED...SUPPORTIVE OF HIGHS
OF 88 TO 93 DEGREES. SAT NIGHT-SUN: THE BEST CHANCE OF SHOWERS AND
STORMS DURING THE LONG TERM PERIOD WILL UNDOUBTEDLY ACCOMPANY THE
ARRIVAL/PASSAGE OF THE POLAR FRONT...ONE WHOSE LOW LEVEL FRONTAL
CIRCULATION WILL BE SUPPORTED THROUGH THE MID-UPPER LEVELS BY
PERSISTENT RIGHT ENTRANCE REGION UPPER JET FORCING. THE COMBINATION
OF INCREASING MID-HIGH CLOUDS AND NUMEROUS TO WIDESPREAD SHOWERS AND
STORMS SHOULD HOLD TEMPERATURES GENERALLY IN THE LOWER TO MIDDLE
80S.
SUN NIGHT-MON NIGHT: SUBSIDENCE DRYING AND LESSENING PROBABILITIES
OF RAIN WILL DEVELOP FROM NW TO SE...BUT NORTHEASTERLY LOW-MID LEVEL
FLOW ON THE WEST SIDE OF THE FRONTAL ZONE AND PROBABLE WAVES OF LOW
PRESSURE WILL RESULT IN MOSTLY CLOUDY CONDITIONS AND A CHANCE OF
RAIN OVER THE EASTERN CWFA...RANGING TO PARTIAL SUNSHINE AND
GENERALLY DRY CONDITIONS OVER THE WESTERN PIEDMONT. COOLER WITH
HIGHS IN THE UPPER 70S TO LOWER 80S.
TUE: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE NORTHEASTERLY
FLOW...AND INCREASING AMOUNTS OF SUNSHINE. MILD WITH HIGHS AGAIN IN
THE UPPER 70S TO LOWER OR PERHAPS MIDDLE 80S.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 150 AM WEDNESDAY...
A LINE OF SHOWERS AND STORMS CROSSING THE MOUNTAINS HAS WEAKENED
DRAMATICALLY SINCE 04Z. OUTFLOW AHEAD OF THE DISSIPATING CONVECTION
MAY STILL TRIGGER A FEW ISOLATED SHOWERS EARLY THIS MORNING...WITH
HIRES MODELS SHOWING A FEW SHOWERS FROM KRDU NORTH BY 09Z.
MEANWHILE...PATCHY STRATUS WILL BE POSSIBLE BY 12Z...WITH SLIGHTLY
HIGHER CHANCES AT KGSO/KINT AND KFAY BASED ON FORECAST SOUNDINGS.
HOWEVER..CONFIDENCE IN IFR OR LIFR CEILINGS IS STILL LOW AT THIS
TIME.
ADDITIONAL SHOWERS AND STORMS ARE EXPECTED TO DEVELOP BY THIS
AFTERNOON AS A THIS MORNINGS OUTFLOW AND A SURFACE TROUGH WILL
LIKELY SERVE AS A FOCUS FOR CONVECTION. WEAK STEERING FLOW AND THE
POTENTIAL FOR VARIOUS OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME
CONVECTION AT ANY SPECIFIC TAF SITE...BUT CONFIDENCE IS FAIRLY HIGH
THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS AFTERNOON/EVENING.
OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING
STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING
COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE
THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD/WSS
NEAR TERM...BLS
SHORT TERM...BLS
LONG TERM...MWS
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 AM EDT WED SEP 3 2014
.SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS
CENTRAL NC TODAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR
THE REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 305 AM WEDNESDAY...
A FEW SHOWERS POPPING UP ALONG REMNANT OUTFLOW FROM CONVECTION
CROSSING THE MOUNTAINS LATE LAST EVENING WILL CONTINUE TO MOVE OFF
TO THE NORTHEAST ACROSS THE NORTHERN PIEDMONT THIS MORNING.
LINGERING INSTABILITY AND RECENT RADAR TRENDS SUGGEST THAT A COUPLE
ISOLATED THUNDERSTORMS ARE POSSIBLE AS WELL. THE OUTLFOW WILL
SETTLE SOUTH THIS MORNING AND SHOULD PRETTY MUCH BISECT THE AREA
FROM SOUTHWEST TO NORTHEAST BASED ON THE LATEST RAP FORECAST. THERE
IS NO REAL AIRMASS CHANGE ACROSS THE AREA AND THE BLENDED TOTAL PW
PRODUCT SHOWS PW VALUES OF 1.8 TO 2 INCHES HIS MORNING. H85 TEMPS
ARE DOWN A COUPLE DEGREES FROM THE LATEST COUPLE OF DAYS AND HIGHS
SHOULD ONLY BE IN THE LOW TO MID 90S TODAY. HOWEVER..THE STRONG
HEATING COMBINED WITH THE MOIST AIRMASS WILL LEAD TO MODERATE
INSTABILITY AGAIN THIS AFTERNOON. LOW-LEVEL CONVERGENCE AND A
REMNANT DISTURBANCE/SHEAR AXIS ALOFT WILL SERVE AS A TRIGGER FOR
SCATTERED TO SOMETIMES NUMEROUS SHOWERS AND STORMS...AND WHILE
MOISTURE/INSTABILITY SHOULD FAVOR BETTER COVERAGE ACROSS THE
SOUTH...WEAK STEERING FLOW AND PROPAGATING OUTFLOWS MAKES IT
DIFFICULT TO ASSESS WHERE STORM COVERAGE WILL BE THE GREATEST. MOST
HIRES GUIDANCE SHOWS STORMS DEVELOPING ACROSS THE SOUTH BY 19Z AND
THEN SHIFTING NORTHWARD AS THE AFOREMENTIONED BOUNDARY WASHES OUT.
HEAVY RAIN...MINOR FLOODING AND A FEW STRONG WIND GUSTS WILL BE THE
MAIN STORM THREATS.
CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE
COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO
SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER
60S AND LOWER 70S.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 305 AM WEDNESDAY...
THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A
SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS
HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE
AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION
SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR
SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED
COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL
THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH
NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL
INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN
THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 255 PM TUESDAY...
FOR THU/FRI: CONTINUED WARM/HUMID WITH DAILY SCATTERED SHOWERS AND
STORMS. AT THE SURFACE... THE WEAK FRONTAL ZONE WILL LIKELY HAVE
WASHED OUT BY THU MORNING... AND THE SURFACE HIGH CENTERED OFF THE
SOUTHEAST COAST WILL INTRODUCE A MOIST CONFLUENT LOW LEVEL FLOW OFF
THE ATLANTIC INTO NC. A POSITIVELY TILTED TROUGH WILL SHIFT FROM
MT/DAKOTAS/SCENTRAL CANADA EARLY THU ACROSS ONT/QUE BY FRI NIGHT...
PROPELLING A COLD FRONT THROUGH THE GREAT LAKES/MID MISS VALLEY. AS
THE FLAT RIDGE HOLDS ACROSS THE SOUTHEAST/MIDSOUTH/GULF STATES
HOWEVER... WE`LL STAY WITHIN AN ENVIRONMENT CHARACTERIZED BY WEAK
SHEAR AND MODERATE INSTABILITY (TEMPERED BY WARM MID LEVELS). PW
VALUES SHOULD STAY ABOVE NORMAL AT 1.7-1.9"... NOT UNEXPECTED GIVEN
THE TROPICAL NATURE OF THE INCOMING AIR MASS... AND SUFFICIENT TO
SUPPORT SCATTERED CONVECTION ALONG THE SEA BREEZE... DYING FRONTAL
ZONE... OR ANY OTHER SUBTLE BOUNDARY. WILL RETAIN AFTERNOON AND
EVENING STORM CHANCES BOTH DAYS... WITH TEMPS HOLDING ABOUT A
CATEGORY ABOVE NORMAL AS THICKNESSES STAY AROUND 10 M ABOVE NORMAL.
FOR SAT-TUE: STILL EXPECT A TRANSITION FROM THE WARM/HUMID WEATHER
TO MORE SEASONABLE CONDITIONS LATE IN THE WEEKEND. THE INITIAL MID
LEVEL TROUGH OVER ERN QUEBEC WILL CONTINUE SHIFTING EAST OVER THE
MARITIMES... WHILE A STRONG SLUG OF STRONG VORTICITY EMANATING FROM
A STRONG COLD VORTEX OVER THE BEAUFORT SEA WILL PUSH EASTWARD CLOSE
ON ITS HEELS... CROSSING HUDSON BAY ON SUNDAY. THIS SHOULD PUSH THE
SURFACE COLD FRONT TO JUST NW OF NC BY SUN... AND WELL INTO THE
STATE BY EARLY MON. BOTH THE GFS AND ECMWF TRACK THEIR COOL PARENT
HIGHS OVER THE ST LAWRENCE VALLEY/SRN QUEBEC MON/TUE... WITH THE
COLD FRONT PUSHING TO ERN NC AND ACROSS NWRN SC. THIS MODEL
AGREEMENT LEADS TO GROWING CONFIDENCE THAT THE PARENT HIGH WILL BE
DENSE ENOUGH TO PUSH THIS COOLER AIR WELL INTO CENTRAL NC...
ALTHOUGH IT MAY NOT HAPPEN UNTIL LATE SUN NIGHT INTO MON MORNING.
WILL FOLLOW THIS TREND WITH TEMPS HOLDING ABOVE NORMAL SAT/SUN (BUT
NOT AS WARM IN THE NORTH SUN DUE TO MORE CLOUDS) WITH HIGHS IN THE
MID 80S TO NEAR 90... BUT THEN EXPECT TEMPS TO PLUNGE FOR MON/TUE
WITH THICKNESSES DROPPING TO 10-20 M BELOW NORMAL... YIELDING HIGHS
NEAR 80 TO LOWER 80S. REGARDING PRECIP CHANCES... WE`RE LIKELY TO
SEE SCATTERED TO PERHAPS NUMEROUS SHOWERS AND STORMS LATE SAT
THROUGH AT LEAST SUN NIGHT... BOTH ALONG THE PREFRONTAL PIEDMONT
TROUGH AND AHEAD OF AND WITH THE FRONT ITSELF. SHOWER/STORM CHANCES
ARE EXPECTED TO PEAK SUN AFTERNOON. WITH THE MID LEVEL TROUGH AXIS
SWINGING THROUGH THE REGION MON... WE MAY SEE LINGERING CHANCES FOR
RAIN ESPECIALLY SOUTH AND EAST. THE SURFACE RIDGE NOSING IN FROM THE
NORTH LATE MON INTO TUE ACCOMPANIED BY LOWERING PW VALUES SHOULD
MEAN MOSTLY DRY WEATHER TUE... AS THE MID LEVEL TROUGH AXIS LIFTS NE
AWAY FROM THE REGION FOLLOWED BY WEAK MID LEVEL SHORTWAVE RIDGING
OVER THE CAROLINAS. -GIH
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 150 AM WEDNESDAY...
A LINE OF SHOWERS AND STORMS CROSSING THE MOUNTAINS HAS WEAKENED
DRAMATICALLY SINCE 04Z. OUTFLOW AHEAD OF THE DISSIPATING CONVECTION
MAY STILL TRIGGER A FEW ISOLATED SHOWERS EARLY THIS MORNING...WITH
HIRES MODELS SHOWING A FEW SHOWERS FROM KRDU NORTH BY 09Z.
MEANWHILE...PATCHY STRATUS WILL BE POSSIBLE BY 12Z...WITH SLIGHTLY
HIGHER CHANCES AT KGSO/KINT AND KFAY BASED ON FORECAST SOUNDINGS.
HOWEVER..CONFIDENCE IN IFR OR LIFR CEILINGS IS STILL LOW AT THIS
TIME.
ADDITIONAL SHOWERS AND STORMS ARE EXPECTED TO DEVELOP BY THIS
AFTERNOON AS A THIS MORNINGS OUTFLOW AND A SURFACE TROUGH WILL
LIKELY SERVE AS A FOCUS FOR CONVECTION. WEAK STEERING FLOW AND THE
POTENTIAL FOR VARIOUS OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME
CONVECTION AT ANY SPECIFIC TAF SITE...BUT CONFIDENCE IS FAIRLY HIGH
THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS AFTERNOON/EVENING.
OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING
STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING
COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE
THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD/WSS
NEAR TERM...BLS
SHORT TERM...BLS
LONG TERM...HARTFIELD
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
150 AM EDT WED SEP 3 2014
.SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS
CENTRAL NC TODAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR
THE REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM TUESDAY...
CONVECTION HAS LARGELY DISSIPATED ACROSS THE AREA THIS EVENING WITH
NOCTURNAL STABILIZATION TAKING HOLD. HOWEVER... AN APPROACHING LINE
OF SHOWERS AND STORMS... CURRENTLY MOVING EAST-SOUTHEASTWARD THROUGH
THE NC AND VA MOUNTAINS... IN ADVANCE OF A WEAK COLD FRONT IS
EXPECTED TO APPROACH/POSSIBLY MOVE INTO PORTIONS OF THE AREA
OVERNIGHT. WITH THE SPC MESOPAGE STILL SHOWING 1000-2000 J/KG OF
MUCAPE ACROSS OUR NORTHWEST/NORTHERN PIEDMONT AND THE LATEST RAP AND
HRRR SHOWING THE POTENTIAL FOR SOME OF THIS ACTIVITY TO MOVE INTO
THIS AREA (NW/N PIEDMONT) WILL LEAVE A CHANCE OF SHOWERS AND STORMS
IN THE FORECAST FOR THIS AREA. HOWEVER.. WITH THE LACK OF GOOD DEEP
SHEAR AND DAYTIME HEATING THINK THIS LINE WILL CONTINUE TO SHOW A
WEAKENING TREND AS IT MOVES INTO NW/N PORTIONS OF CENTRAL NC AROUND
MIDNIGHT OR SHORTLY AFTER. THUS... WOULD EXPECT ANY OF THIS
WEAKENING LINE TO REMAIN BELOW SEVERE LIMITS.
WHERE HEAVY RAINFALL OCCURRED THIS PAST AFTERNOON-EVENING (GENERALLY
ALONG AND SOUTH OF A LINE FROM ASHEBORO TO RALEIGH TO WILSON) AND
SKIES PARTIALLY CLEAR OVERNIGHT... WE COULD SEE PATCHES OF FOG
DEVELOP DURING THE PRE-DAWN HOURS OF WEDNESDAY. MIN TEMPS NEAR 70-
LOWER 70S.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 335 PM TUESDAY...
SHEAR AXIS AND ATTENDANT SURFACE BOUNDARY WILL LIE ACROSS THE
SOUTHERN COUNTIES OF CENTRAL NC. ISOLATED SHOWERS AND STORMS ALONG
THIS FEATURE WEDNESDAY MORNING WILL GROW IN COVERAGE AS THE
ATMOSPHERE HEATS UP...LEADING TO GREATER LOW LEVEL INSTABILITY.
RELATIVELY WEAK STEERING FLOW SUGGEST THAT THE STORMS WILL BE SLOW
MOVING. IF STORMS OCCUR OVER URBAN LOCATIONS...THIS MAY LEAD TO
MINOR FLOODING OF STREETS AND POOR DRAINAGE AREAS.
PLAN TO CAP POPS AT 50 PERCENT ACROSS THE SOUTH...DWINDLING TO 25-35
PERCENT ACROSS THE NW.
MAX TEMPS WEDNESDAY DEPENDENT ON WHEN CONVECTIVE COVERAGE INCREASES
AND WHETHER ANY PERIODS OF PARTIAL SUN OCCUR. BETTING ON SOME
PARTIAL SUN INT HE LATE MORNING-EARLY AFTERNOON PRIOR TO CONVECTION
INCREASING AFTER 2-3 PM. IF SKIES REMAIN OVERCAST OR CONVECTION
BECOMES ACTIVE BY LUNCHTIME...MAX TEMPS MAY END UP BEING 5-6 DEGREES
COOLER. CONTINUED WARM AND MUGGY WEDNESDAY NIGHT WITH SCATTERED
CONVECTION SLOWLY DIMINISHING/DISSIPATING. MIN TEMPS NEAR 70-LOWER
70S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 255 PM TUESDAY...
FOR THU/FRI: CONTINUED WARM/HUMID WITH DAILY SCATTERED SHOWERS AND
STORMS. AT THE SURFACE... THE WEAK FRONTAL ZONE WILL LIKELY HAVE
WASHED OUT BY THU MORNING... AND THE SURFACE HIGH CENTERED OFF THE
SOUTHEAST COAST WILL INTRODUCE A MOIST CONFLUENT LOW LEVEL FLOW OFF
THE ATLANTIC INTO NC. A POSITIVELY TILTED TROUGH WILL SHIFT FROM
MT/DAKOTAS/SCENTRAL CANADA EARLY THU ACROSS ONT/QUE BY FRI NIGHT...
PROPELLING A COLD FRONT THROUGH THE GREAT LAKES/MID MISS VALLEY. AS
THE FLAT RIDGE HOLDS ACROSS THE SOUTHEAST/MIDSOUTH/GULF STATES
HOWEVER... WE`LL STAY WITHIN AN ENVIRONMENT CHARACTERIZED BY WEAK
SHEAR AND MODERATE INSTABILITY (TEMPERED BY WARM MID LEVELS). PW
VALUES SHOULD STAY ABOVE NORMAL AT 1.7-1.9"... NOT UNEXPECTED GIVEN
THE TROPICAL NATURE OF THE INCOMING AIR MASS... AND SUFFICIENT TO
SUPPORT SCATTERED CONVECTION ALONG THE SEA BREEZE... DYING FRONTAL
ZONE... OR ANY OTHER SUBTLE BOUNDARY. WILL RETAIN AFTERNOON AND
EVENING STORM CHANCES BOTH DAYS... WITH TEMPS HOLDING ABOUT A
CATEGORY ABOVE NORMAL AS THICKNESSES STAY AROUND 10 M ABOVE NORMAL.
FOR SAT-TUE: STILL EXPECT A TRANSITION FROM THE WARM/HUMID WEATHER
TO MORE SEASONABLE CONDITIONS LATE IN THE WEEKEND. THE INITIAL MID
LEVEL TROUGH OVER ERN QUEBEC WILL CONTINUE SHIFTING EAST OVER THE
MARITIMES... WHILE A STRONG SLUG OF STRONG VORTICITY EMANATING FROM
A STRONG COLD VORTEX OVER THE BEAUFORT SEA WILL PUSH EASTWARD CLOSE
ON ITS HEELS... CROSSING HUDSON BAY ON SUNDAY. THIS SHOULD PUSH THE
SURFACE COLD FRONT TO JUST NW OF NC BY SUN... AND WELL INTO THE
STATE BY EARLY MON. BOTH THE GFS AND ECMWF TRACK THEIR COOL PARENT
HIGHS OVER THE ST LAWRENCE VALLEY/SRN QUEBEC MON/TUE... WITH THE
COLD FRONT PUSHING TO ERN NC AND ACROSS NWRN SC. THIS MODEL
AGREEMENT LEADS TO GROWING CONFIDENCE THAT THE PARENT HIGH WILL BE
DENSE ENOUGH TO PUSH THIS COOLER AIR WELL INTO CENTRAL NC...
ALTHOUGH IT MAY NOT HAPPEN UNTIL LATE SUN NIGHT INTO MON MORNING.
WILL FOLLOW THIS TREND WITH TEMPS HOLDING ABOVE NORMAL SAT/SUN (BUT
NOT AS WARM IN THE NORTH SUN DUE TO MORE CLOUDS) WITH HIGHS IN THE
MID 80S TO NEAR 90... BUT THEN EXPECT TEMPS TO PLUNGE FOR MON/TUE
WITH THICKNESSES DROPPING TO 10-20 M BELOW NORMAL... YIELDING HIGHS
NEAR 80 TO LOWER 80S. REGARDING PRECIP CHANCES... WE`RE LIKELY TO
SEE SCATTERED TO PERHAPS NUMEROUS SHOWERS AND STORMS LATE SAT
THROUGH AT LEAST SUN NIGHT... BOTH ALONG THE PREFRONTAL PIEDMONT
TROUGH AND AHEAD OF AND WITH THE FRONT ITSELF. SHOWER/STORM CHANCES
ARE EXPECTED TO PEAK SUN AFTERNOON. WITH THE MID LEVEL TROUGH AXIS
SWINGING THROUGH THE REGION MON... WE MAY SEE LINGERING CHANCES FOR
RAIN ESPECIALLY SOUTH AND EAST. THE SURFACE RIDGE NOSING IN FROM THE
NORTH LATE MON INTO TUE ACCOMPANIED BY LOWERING PW VALUES SHOULD
MEAN MOSTLY DRY WEATHER TUE... AS THE MID LEVEL TROUGH AXIS LIFTS NE
AWAY FROM THE REGION FOLLOWED BY WEAK MID LEVEL SHORTWAVE RIDGING
OVER THE CAROLINAS. -GIH
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 150 AM WEDNESDAY...
A LINE OF SHOWERS AND STORMS CROSSING THE MOUNTAINS HAS WEAKENED
DRAMATICALLY SINCE 04Z. OUTFLOW AHEAD OF THE DISSIPATING CONVECTION
MAY STILL TRIGGER A FEW ISOLATED SHOWERS EARLY THIS MORNING...WITH
HIRES MODELS SHOWING A FEW SHOWERS FROM KRDU NORTH BY 09Z.
MEANWHILE...PATCHY STRATUS WILL BE POSSIBLE BY 12Z...WITH SLIGHTLY
HIGHER CHANCES AT KGSO/KINT AND KFAY BASED ON FORECAST SOUNDINGS.
HOWEVER..CONFIDENCE IN IFR OR LIFR CEILINGS IS STILL LOW AT THIS
TIME.
ADDITIONAL SHOWERS AND STORMS ARE EXPECTED TO DEVELOP BY THIS
AFTERNOON AS A THIS MORNINGS OUTFLOW AND A SURFACE TROUGH WILL
LIKELY SERVE AS A FOCUS FOR CONVECTION. WEAK STEERING FLOW AND THE
POTENTIAL FOR VARIOUS OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME
CONVECTION AT ANY SPECIFIC TAF SITE...BUT CONFIDENCE IS FAIRLY HIGH
THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS AFTERNOON/EVENING.
OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING
STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING
COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE
THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD/WSS
NEAR TERM...BSD/WSS
SHORT TERM...WSS
LONG TERM...HARTFIELD
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1231 AM EDT WED SEP 3 2014
.SYNOPSIS...
HIGH PRESSURE WILL BUILD NORTHEAST UP THE APPALACHIAN MOUNTAINS
THROUGH WEDNESDAY NIGHT AND OFF THE EAST COAST BY THURSDAY NIGHT. A
WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA THURSDAY FOLLOWED BY
A COLD FRONT FRIDAY EVENING. HIGH PRESSURE WILL BUILD SOUTHEAST
ACROSS THE REGION INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CONVECTION WITH DIFFUSE COLD FRONT NOW REDUCED TO 3 SMALL CLUSTERS.
VERY LITTLE LIGHTNING OCCURRING. RUC HANGS ON TO A FEW CELLS THRU
THE NIGHT SO WILL SLOW POP DROP OFF ENOUGH TO KEEP SLIGHT CHANCE
GOING LONGER INTO THE NIGHT.
MUCH OF THE CLOUD COVER FROM EARLIER IN THE DAY HAS DISSIPATED
LEAVING PATCHY LOWER CLOUDS WITH BAND OF JET INDUCED CIRRUS ABOVE.
WEAK COLD ADVECTION LOOKS EVEN MORE LIKELY TO NOT BE STRONG ENOUGH
TO BRING IN THE DRIER AIR AS QUICK AS THOUGHT EARLIER SO WILL INCH
LOWS UP EVEN ANOTHER DEG OVER THE SE 2/3 OF THE AREA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
BROAD UPPER LEVEL TROUGH WILL MOVE EAST OF THE AREA OVERNIGHT
SETTING UP A ZONAL FLOW ACROSS THE COUNTRY ONCE AGAIN. SURFACE HIGH
WILL BUILD NORTHEAST AND THEN EAST OF THE AREA BY WEDNESDAY NIGHT.
WARM AIR ADVECTION WILL RESUME ON THURSDAY WITH A PRETTY GOOD SURGE
OF WARM AIR RACING NORTHEAST INTO THE FORECAST AREA. 850 MB
TEMPERATURES RISE FROM 16C WEDNESDAY NIGHT TO 20C BY FRIDAY.
INCREASED DEW POINT AIR WILL RETURN AND BRING WITH IT HIGHER
HUMIDITY ON FRIDAY.
COLD FRONT IS EXPECTED TO MOVE EAST ACROSS THE REGION FRIDAY
EVENING. CONVECTION IS EXPECTED TO REMAIN ASSOCIATED WITH THE COLD
FRONT FRIDAY AFTERNOON INTO FRIDAY NIGHT. OTHERWISE...NO MAJOR
THREAT FOR SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED PERIOD
UNTIL FRIDAY AFTERNOON. WILL HAVE TO KEEP AN EYE ON THE COLD FRONT
FRIDAY FOR SEVERE POTENTIAL DUE TO IDEAL TIMING IN THE HEAT OF THE
DAY.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
A SURFACE COLD FRONT WILL BE JUST ABOUT OUT OF THE AREA AT DAYBREAK
SATURDAY. THERE COULD BE A FEW SHOWERS ALONG AND BEHIND THE FRONT
BUT RAPID DRYING WILL OCCUR DURING THE AFTERNOON. READINGS NEXT
WEEKEND WILL BE BACK BELOW NORMAL WITH LOWS MONDAY MORNING POSSIBLY
GETTING INTO THE 40S. SUNDAY WILL BE A PLEASANT DAY WITH ABUNDANT
SUNSHINE. THE FALL LIKE WEATHER WILL CONTINUE ON MONDAY. THE
SURFACE HIGH RESPONSIBLE FOR THE QUIET WEATHER WILL EVENTUALLY MOVE
OFF TO THE EAST ON TUESDAY ALLOWING WARMER SOUTHERLY FLOW TO
RETURN. EXPECT TEMPS TUESDAY TO AVERAGE NEAR NORMAL. PRECIP
CHANCES SHOULD HOLD OFF TILL JUST AFTER THE PERIOD ENDS.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL BUILD IN TODAY BEHIND A COLD FRONT THAT WILL BE
SOUTH OF THE AREA. MAIN CONCERN IS FOR EARLY OVERNIGHT/EARLY
MORNING FOG AND LOW STRATUS DEVELOPING ACROSS THE AREA. AMPLE LOW
LEVEL MOISTURE...DRYING ALOFT...AND LIGHT WINDS SHOULD ALLOW THE
FOR TO DEVELOP WITH WIDESPREAD MVFR/IFR RESTRICTIONS DEVELOPING
BEFORE DAYBREAK. AFTER FOG LIFTS EXPECT VFR CONDITIONS THROUGH THE
DAY. NEAR LAKE ERIE...KCLE AND KERI...EXPECT LAKE BREEZE TO
DEVELOP IN WEAK GRADIENT.
OUTLOOK...NON VFR LIKELY IN SHOWERS AND THUNDERSTORMS BY FRIDAY
EVENING INTO SATURDAY WITH THE NEXT COLD FRONT.
&&
.MARINE...
A SURFACE COLD FRONT WILL MOVE EAST OF THE LAKE BY EARLY THIS
EVENING. LINGERING SHOWERS OVER THE LAKE WILL ALSO BE GONE BY THAT
TIME. EXPECT THE FLOW TO BECOME WESTERLY BEHIND THE FRONT AND THEN
LIGHT AND VARIABLE OVERNIGHT. LIGHT FLOW WILL THEN CONTINUE
WEDNESDAY WITH SOUTHERLY FLOW DEVELOPING ON THURSDAY AS A SURFACE
RIDGE PUSHES EAST OF THE LAKE. SOUTH TO SOUTHWEST FLOW WILL THEN
GRADUALLY INCREASE AHEAD OF A COLD FRONT THAT WILL DROP SOUTH ACROSS
THE LAKE EARLY SATURDAY. MORE PRECIP IS LIKELY WITH THIS FRONT WITH
THE FLOW BECOMING NORTH BEHIND IT. DO NOT THINK SPEEDS WILL BE
STRONG ENOUGH FOR SMALL CRAFT HEADLINES. NORTHERLY FLOW WILL
CONTINUE THROUGH SUNDAY. SPEEDS MOST IF NOT THE ENTIRE PERIOD WILL
BE UNDER 15 KNOTS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...KUBINA
AVIATION...TK
MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1132 PM CDT TUE SEP 2 2014
.AVIATION...
CONFIDENCE IS A BIT LOWER THAT AN IFR OR MVFR CLOUD DECK WILL
DEVELOP NEAR OR SOUTHWEST OF KLBB EARLY WEDNESDAY...AND ADVECT
OVER THE AIRPORT. LATEST WRF/NAM HAS DRIED THE H850 MB A BIT WHILE
THE RAP H850 MB LAYER IS SLIGHTLY MORE MOIST THAN PREVIOUS RUNS.
ALTHOUGH WE WILL BACK OFF SLIGHTLY ON THE CLOUD LAYER POTENTIAL...
WE WILL RETAIN SOME CHANCE OF A DECK IMPACTING KLBB JUST AFTER
DAYBREAK WEDNESDAY. OTHERWISE...UPPER LEVEL HIGH PRESSURE WILL
DOMINATE THROUGH WEDNESDAY WITH WEAKER FLOW THAN TUESDAY AND
LESSER THUNDER CHANCES. A LOW LEVEL JET TONIGHT SHOULD REMAIN JUST
TO THE NORTH OF THE AREA. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 706 PM CDT TUE SEP 2 2014/
AVIATION...
ISOLATED THUNDERSTORMS APPEAR TO HAVE BY-PASSED KLBB WHILE
REMAINING FAR WEST OF KCDS THIS EVENING. VFR EXPECTED TO DOMINATE
OTHER THAN A RISK FOR AN IFR/MVFR CLOUD LAYER TO DEVELOP JUST
AFTER DAYBREAK WEDNESDAY AT KLBB. RMCQUEEN
PREV DISCUSSION... /ISSUED 531 PM CDT TUE SEP 2 2014/
UPDATE...
THUNDERSTORMS HAVE DEVELOPED OVER THE WESTERN AND CENTRAL SOUTH
PLAINS...A BIT SOUTH OF PREVIOUS BEST-GUESS...BUT GIVE SHORT TERM
SOLUTIONS SOME CREDIT. WE HAVE UPDATED FOR LOW COVERAGE THUNDER
THROUGH EARLY THIS EVENING. 1500-2000 JOULES PER KILOGRAM OF
CONVECTIVE ENERGY BUT VERY LITTLE SHEAR CONTRIBUTING TO BRIEF
HEAVY SHOWERS AND BRIEF MOSTLY WEAK HAIL INDICATIONS AT THIS TIME.
ACTIVITY SHOULD TAKE ON BETTER NORTHERLY DRIFT...THOUGH BELIEVE
MOST ACTIVITY WILL RELENT BY DARK. RMCQUEEN
PREV DISCUSSION... /ISSUED 306 PM CDT TUE SEP 2 2014/
SHORT TERM...
FOCUS IN THE SHORT TERM IS ON SMALL CHANCE FOR ISOLATED SHOWERS
AND/OR THUNDERSTORMS LATE THIS AFTN AND THIS EVENING. RADAR IS QUIET
ATTM BUT SATELLITE SHOWING AN AREA OF CUMULUS DEVELOPMENT TO THE
EAST AND SOUTHEAST OF LUBBOCK IN AN AREA WHERE OBJECTIVE ANALYSIS
SHOWS ENHANCED INSTABILITY AND WEAKENING INHIBITION. SOME VERY
MODEST LOW LEVEL SPEED CONVERGENCE AND MOISTURE ADVECTION IN THIS
AREA MAY NOT HELP TOO MUCH BUT CERTAINLY WILL NOT HURT. A WEAK
FRONTAL BOUNDARY PULLED UP STATIONARY NEAR A MORTON TO TULIA LINE
WITH WEAK CONFLUENCE IN ITS VICINITY BUT WITH SFC DEW POINTS ABOUT 5
DEGREES LOWER THAN IN THE FORMER AREA. WOULD EXPECT THESE TWO AREAS
HAVE THE BEST CHANCE OF SEEING CONVECTIVE DEVELOPMENT. 12Z WRF-NAM
HIGHLIGHTS THE LATTER WHILE RECENT RUNS OF THE HRRR FEATURES THE
FORMER. EITHER WAY WILL LIKELY BE DIFFICULT TO GENERATE ANYTHING
OTHER THAN SMALL-SCALE AND ISOLATED SHOWERS WITH AREAL COVERAGE NOT
WARRANTING MENTION IN THE ZONE FCST ATTM.
WEDNESDAY SHOULD BE EVEN MORE DIFFICULT TO PRODUCE PRECIP WITH
STRENGTHENING HIGH PRESSURE OVERHEAD AND LOW LEVEL FLOW BECOMING
MORE UNIFORM FROM THE SOUTH. TEMPS TO REMAIN WARMER THAN NORMAL WITH
BOTH LOWS AND HIGHS NEAR WARMER MAV GUIDANCE LOOKING MORE LIKELY
ATTM.
LONG TERM...
ONLY MINOR CHANGES TO THE LONG TERM FORECAST FOR THIS ITERATION...AS
A MUTED COOLING TREND WILL BE FOLLOWED BY A POTENTIALLY WET WEEKEND
FOR PARTS OF THE REGION.
BY WEDNESDAY EVENING...A MOSTLY ZONAL UPPER FLOW REGIME WILL BE IN
PLACE ACROSS THE CONUS...WITH AN ELONGATED UPPER RIDGE IN PLACE
ACROSS MOST OF THE SOUTH...INCLUDING WEST TEXAS. WHILE THIS WILL
CONTINUE TO ENSURE MOSTLY DRY CONDITIONS THROUGH THE END OF THE WORK
WEEK...GRADUALLY DROPPING 1000-500 MB THICKNESSES WILL ALLOW
TEMPERATURES TO INCREMENTALLY FALL BACK TO A MORE REASONABLE UPPER
80S ON THE SOUTH PLAINS TO MID 90S ON THE ROLLING PLAINS.
BY LATE IN THE WEEK AND THROUGH THE WEEKEND...A BROAD UPPER TROUGH
WILL PUSH EASTWARD ACROSS THE NORTHERN CONUS...SENDING A
MODEST COLD FRONT SOUTHWARD THROUGH THE CENTRAL PLAINS AND AT LEAST
THE TEXAS PANHANDLE. MEANWHILE DEEPER MONSOONAL MOISTURE...POSSIBLY
WITH A CONNECTION TO REMNANTS OF TROPICAL STORM DOLLY...WILL BE
DRAWN NORTHWARD INTO THE SOUTHWEST AND EVENTUALLY EASTWARD AS IT
GETS CAUGHT IN THE WESTERLY UPPER FLOW ASSOCIATED WITH THE
PREVIOUSLY MENTIONED TROUGH. ALL OF THIS IS EXPECTED TO RESULT IN
INCREASING RAIN CHANCES BEGINNING AS EARLY AS LATE FRIDAY...AND
POSSIBLY LASTING THROUGH LATE SUNDAY DEPENDING ON A FEW FACTORS.
THE MOST PROMINENT OF THESE FACTORS SEEMS TO BE THE TIMING AND
STRENGTH OF THE APPROACHING COLD FRONT...AS THE GFS AND ECMWF REMAIN
ABOUT 24 HOURS APART IN THIS REGARD. THE GFS INDICATES A
SLOWER...WEAKER FRONT REACHING THE NORTHERN BORDER OF THE CWA LATE
SATURDAY AFTERNOON AND WASHING OUT ACROSS THE CWA SUNDAY.
MEANWHILE...THE ECMWF SOLUTION BRINGS THIS FRONT INTO THE AREA AS
EARLY AS LATE FRIDAY...AND PUSHES THE BOUNDARY WELL THROUGH THE CWA
BY LATE SATURDAY. THE LATTER SOLUTION NOT SURPRISINGLY DEVELOPS THE
HEAVIEST PRECIPITATION DURING THE LATE FRIDAY THROUGH SATURDAY
TIME FRAME...WHILE THE GFS SEEMS TO BE FOCUSING ON THE LATE SATURDAY
THROUGH LATE SUNDAY TIME FRAME. GIVEN THAT THE BOUNDARY WILL BE WELL
REMOVED FROM ITS PARENT TROUGH BY THE TIME IT REACHES THIS
LATITUDE...WE WILL CONTINUE TO SIDE WITH THE SLOWER GFS SOLUTION AND
HIGHLIGHT LATE SATURDAY WITH THE HIGHEST POPS. LIKEWISE...LOW END POPS
WERE ALSO EXTENDED THROUGH SUNDAY EVENING GIVEN THAT IN THIS SLOWER
SCENARIO REMNANTS OF THIS BOUNDARY AND AMPLE MOISTURE WOULD LIKELY
LINGER THROUGH THIS PERIOD. HOWEVER...UNCERTAINTIES REGARDING
FRONTAL TIMING AND STRENGTH ARE COMPOUNDED FURTHER ON SUNDAY WITH
THE POSSIBILITY OF LINGERING NOCTURNAL CONVECTION AND STABILIZING
OUTFLOWS.
BY MONDAY...THE UPPER RIDGE IS EXPECTED TO SLIGHTLY AMPLIFY ACROSS
THE SOUTHERN PLAINS WHILE THE COLUMN DRIES CONSIDERABLY. THIS
SHOULD TAPER OFF PRECIPITATION CHANCES UNTIL LATER IN THE WEEK WHEN
ANOTHER POSSIBLY STRONGER COLD FRONT MOVES THROUGH THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 61 92 62 90 62 / 10 0 10 10 10
TULIA 68 93 66 91 66 / 20 0 10 0 10
PLAINVIEW 68 93 66 90 66 / 20 0 0 0 10
LEVELLAND 66 92 66 90 67 / 20 0 10 10 0
LUBBOCK 72 93 68 92 67 / 20 0 0 10 0
DENVER CITY 66 91 66 89 66 / 20 0 10 10 10
BROWNFIELD 68 93 67 90 67 / 20 0 0 10 0
CHILDRESS 75 97 75 96 72 / 10 0 0 0 0
SPUR 73 97 72 94 71 / 10 0 0 10 10
ASPERMONT 76 99 74 96 73 / 0 0 0 10 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/05
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1059 PM MDT TUE SEP 2 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 420 PM MDT TUE SEP 2 2014
MAIN FORECAST CONCERN OVER THE NEXT FEW DAYS WILL BE THE
CRITICAL FIRE WEATHER CONDITIONS ACROSS THE CWA. IT TOOK A LITTLE
WHILE FOR RH VALUES TO DROP TO CRITICAL LEVELS THIS
AFTERNOON...BUT WE ARE CURRENTLY SEEING A RH OF AROUND 15 PERCENT
IN THE FOOTHILLS OF THE LARAMIE RANGE (FIRE WEATHER ZONES 309 AND
301). RH VALUES ARE GENERALLY 15-20 PERCENT TO THE WEST OF THE
LARAMIE RANGE. WITH GUSTS TO 25-30 MPH THROUGH EARLY
EVENING...THIS CONTINUES TO LOOK LIKE A MARGINAL RED FLAG EVENT
AND WILL KEEP THE WARNINGS GOING. CLOUD COVER THIS AFTERNOON IS
QUITE LIMITED WITH ONLY ISOLATED CUMULUS. SFC MOISTURE IS BETTER
IN SOUTHERLY WINDS JUST TO THE EAST OF THE CWA (DEUEL AND GARDEN
COUNTIES) BUT IT WILL BE TOUGH TO ADVECT THIS MOISTURE WESTWARD.
THE HRRR MODEL ALONG WITH THE OTHER MODELS DO NOT SHOW ANY QPF
OVER THE PANHANDLE TONIGHT SO WILL KEEP SLIGHT CHANE POPS OUT OF
THE FCST.
WEDNESDAY CONTINUES TO LOOK LIKE A MORE CRITICAL FIRE WEATHER DAY
OVER THE REGION. A SHORTWAVE MOVING FROM WASHINGTON INTO MONTANA
WILL INDUCE PRESSURE FALLS OVER WESTERN SOUTH DAKOTA WHICH
STRENGTHENS THE PRESSURE GRADIENT OVER ESPECIALLY SOUTHEAST WY.
MOS GUIDANCE SHOWS WINDS ABOUT 5 KTS HIGHER THAN THIS AFTN ALONG
WITH AN ADDITIONAL 5 DEGREES OF WARMING. THE FIRE WEATHER WATCH
FOR TOMORROW AFTN INCLUDES TWO ZONES (310 AND 306) THAT ARE NOT
INCLUDED IN TODAYS RED FLAG WARNING. THIS LOOKS GOOD SINCE BOTH
THESE ZONES WERE CLOSE TO HITTING THE CRITERIA TODAY AND
CONDITIONS WILL BE DRIER AND MORE BREEZY TOMORROW. THE DEEP
SOUTHWESTERLY FLOW WILL RESULT IN A VERY WARM DAY WITH HIGHS
RISING INTO THE UPPER 80S TO MID 90S ACROSS THE PLAINS. THIS COULD
BE ONE OF THE WARMEST DAYS FOR THE REST OF THE YEAR SINCE A COLD
FRONTAL PASSAGE IS STILL PROGGED FOR THURS MORNING. TEMPS WILL
DROP CLOSE TO 20 DEGREES ON THURS. STILL NO GOOD CHANCE OF PRECIP
THROUGH AT LEAST THURS EVENING. COULD BE ISOLATED SHOWERS
DEVELOPING BY THURS NIGHT ALTHOUGH THE MODEL TREND HAS BEEN TO
SHIFT THE MORE WIDESPREAD RAIN WELL TO THE SOUTH OVER NORTHWEST KS.
.LONG TERM...(FRIDAY THROUGH MONDAY NIGHT)
ISSUED AT 420 PM MDT TUE SEP 2 2014
MODELS ARE IN FAIR AGREEMENT WITH THE MEDIUM RANGE PERIOD SHOWING A
PERSISTENT QUASI-ZONAL PATTERN OVER THE CENTRAL CONUS. TEMPERATURES
WILL START OFF BELOW AVERAGE ON FRIDAY IN THE POST FRONTAL
AIRMASS...WITH THE SFC HIGH SLIDING TO THE SOUTHEAST ACROSS THE
CENTRAL PLAINS. SFC WINDS ACROSS THE HIGH PLAINS WILL BE OUT OF THE
SOUTHEAST AS THE SFC HIGH SLIDES SOUTHEAST...WITH CONVECTION
DEVELOPING OVER THE MOUNTAINS IN THE LATE AFTERNOON IN THIS LLVL
UPSLOPE REGIME. SHOULD STAY FAIRLY CAPPED ACROSS THE PLAINS WITHIN
THE COOLER AIRMASS...BUT CANT RULE OUT SHOWERS/WEAK TSTORMS
MAINTAINING AS THEY MOVE OFF THE MOUNTAINS AS A 70 KT JET AND
SHORTWAVE ENERGY WILL BE MOVING OVERHEAD AT THIS TIME. SATURDAY
LOOKS VERY SIMILAR ALBEIT WITH WEAKER UPSLOPE FLOW AND SLIGHTLY
WARMER TEMPS/HIGH INSTABILITY. SUNDAY AND MONDAY COULD SEE A BIT
MORE SUBTROPICAL MOISTURE ADVECT UP FROM THE SOUTHWEST AS A TROUGH
DIGS ALONG THE WEST COAST AND MOVES ACROSS THE GREAT BASIN. THE
DEEPEST MOISTURE LOOKS TO REMAIN TO OUR SOUTH...BUT CAN SEE SOME OF
THIS MOISTURE MAKING IT UP TO SOUTHERN PORTIONS OF THE CWA SO WILL
MAINTAIN AT LEAST SLIGHT CHANCE POPS FOR MUCH OF THE CWA. TEMPS WILL
INCREASE BACK TO MORE NORMAL VALUES FOR THIS TIME OF YEAR BY MONDAY
AS THE UPPER TROUGH DEEPENS AND A WARM AIR ADVECTION PATTERN
DEVELOPS OVER THE ROCKIES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING)
ISSUED AT 1058 PM MDT TUE SEP 2 2014
VFR CONDITIONS TO PREVAIL THRU THE PERIOD. WINDS WILL BE GENERALLY
LIGHT AT LESS THAN 10 KNOTS OVERNIGHT...BUT BECOME GUSTY AFTER 16Z
WEDNESDAY.
&&
.FIRE WEATHER...
ISSUED AT 649 PM MDT TUE SEP 2 2014
PER OUR FIRE WEATHER BRIEFING AND MODEL GUIDANCE...RED FLAG
CONDITIONS LOOKING EVEN MORE LIKELY FOR PORTIONS OF SOUTHEAST
WYOMING ON WEDNESDAY...THUS WE HAVE UPGRADED THE FIRE WEATHER
WATCH TO A RED FLAG WARNING...AND HAVE ALSO CANCELLED THE RED
FLAG WARNING THAT WAS IN EFFECT FOR THIS AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM NOON TO 7 PM MDT WEDNESDAY FOR WYZ301-302-
304-306-309-310.
NE...NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...RJM
AVIATION...HAHN
FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
955 AM EDT WED SEP 3 2014
.DISCUSSION...
LATEST RUC ANALYSIS SHOWING AN H100-H70 HI PRES RIDGE EXTENDING FM
THE NRN GULF COAST INTO THE W ATLC...BISECTED BY AN ERLY WAVE BTWN
FL AND THE BAHAMA BANK. WV SAT IMAGERY CONTINUES TO SHOW A BAND OF
DRY MID LYR AIR DRAPED OVER THE S HALF OF FL...THOUGH DEEPER
MOISTURE ASSOCD WITH THE WAVE WAS IMPINGING ON THE SE FL COAST.
MORNING RAOBS CONFIRM THIS WITH PWAT READINGS ARND 1.6" AT
KXMR/KTBW...INCREASING TO 1.9" AT KMFL. MID LVL THERMODYNAMIC
PROFILE HAS BECOME A SLIGHTLY MORE UNSTABLE OVER THE PAST 24HRS WITH
H70 TEMPS ARND 8C...H50 TEMPS ARND -7C...THOUGH LAPSE RATES THRU THE
LYR ARE LANGUISHING BTWN 5.5-6.0C/KM.
ONE NOTEWORTHY TREND ON THE KXMR SOUNDING IS AN INCREASE IN H100-H70
MOISTURE. TREND WILL CONTINUE THRU THE DAY AS RUC ANALYSIS SHOWS
MEAN RH VALUES THRU THE LYR INCREASING UPSTREAM TO ARND 85PCT.
ALTHOUGH THE ASCENDING BACKSIDE OF THE APPROACHING ERLY WAVE REMAINS
BACK OVER THE BAHAMA BANK/FL STRAITS...WITH SFC DEWPOINTS HOLDING IN
THE L/M70S...SHOULD SEE HIGHER PRECIP COVERAGE ACRS E CENT FL THAN
IN RECENT DAYS.
LCL PRECIP MODELS FOCUSING MOST ACTIVITY OVER THE INTERIOR AND ALONG
THE TREASURE COAST...BY AND LARGE BYPASSING THE SPACE COAST. FCST IS
REASONABLE AS STEERING LVL WINDS WILL SHIFT TO THE SE AS THE WAVE
PUSHES ACRS THE REGION THRU LATE AFTN. MINOR ADJUSTMENTS TO PRECIP
TIMING AND COVERAGE...BUT OVERALL TREND WILL REMAIN. COASTAL SHRAS
THRU ERLY AFTN WITH PRECIP SHIFTING INLAND ON THE SEABREEZE. SCT
TSTMS DVLPG INTERIOR THRU LATE AFTN...LINGERING DRY AIR ALOFT WILL
ADD TO DOWNBURST POTENTIAL.
&&
.AVIATION...
THRU 03/16Z...E/SE SFC WNDS AOB 8KTS...BRIEF ISOLD MVFR COASTAL
SHRAS BTWN KTIX-KSUA. BTWN 03/16Z-03/24Z...E/SE SFC WND 8-12KTS...SW
OF KVRB-KDED SCT MVFR SHRAS/ISOLD IFR TSRAS WITH PSBL SFC WND
G25-30KTS...E OF KVRB-KDED ISOLD MVFR SHRAS. AFT 04/00Z...SE SFC
WNDS AOB 5KTS...SCT MVFR SHRAS/ISOLD IFR TSRAS CSTL SITES.
&&
.MARINE...
ERLY WAVE AXIS BTWN THE FL PENINSULA AND THE BAHAMA BANK WILL DRIFT
WEST AND PRODUCE A GENTLE TO MODERATE E/SE BREEZE ACRS THE LCL
ATLC...SEAS SEAS 2-3FT WITH DOMINANT PDS AOA 8SEC. SHRA/TSTM
ACTIVITY WILL INCREASE THRU LATE AFTN AS THE E FL PENINSULA GAINS
THE WAVE`S ASCENDING REAR FLANK.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECAST/AVIATION...BRAGAW
RADAR/IMPACT WX.....CRISTALDI
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
651 AM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 645 AM CDT WED SEP 3 2014
A NARROW N-S BAND OF WIDELY SCATTERED THUNDERSTORMS DEVELOPED
OVER THE LAST HALF HOUR THROUGH THE HIGHWAY 83 CORRIDOR.THIS
APPEARS TO BE ASSOCIATED WITH AN 850 MB MOISTURE TRANSPORT SIGNAL
ACROSS SOUTHWEST KANSAS. THE HRRR MODEL IS ALSO PICKING UP ON THIS
ACTIVITY AND HAVE UPDATED FOR A MENTION OF THUNDERSTORMS THROUGH
MID MORNING FROM GARDEN CITY TO DODGE CITY AND HAYS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 339 AM CDT WED SEP 3 2014
THE WEAK FRONTAL BOUNDARY THAT WAS RESIDING ALONG THE WESTERN KANSAS-
OKLAHOMA BORDER CONTINUED TO SLOWLY DISSOLVE AS WINDS NORTH OF THE
FRONT WERE STILL VEERING FROM 090 TO 140 AT DDC. WINDS WERE ALSO 10
TO 12 KNOTS WHICH WAS KEEPING THE BOUNDARY LAYER MIXED ENOUGH TO
PREVENT FOG DEVELOPMENT. LOW STRATUS IS ABOUT ALL WE CAN EXPECT
EXCEPT FOR EXTREME WEST-CENTRAL KANSAS, SO WE WILL KEEP AREAS OF
1/2SM FOG CONFINED TO SYRACUSE TO SCOTT CITY AREAS. VERY WARM LOWER
TROPOSPHERIC AIR WILL CONTINUE TO EXPAND NORTH-NORTHEASTWARD THROUGH
THE DAY. HIGHS AROUND 100F ARE LIKELY ALONG/WEST OF HIGHWAY 83 TO
THE COLORADO BORDER. LEE TROUGH CONVERGENCE AXIS WILL SET UP ALONG
THE COLORADO BORDER AS WELL BY MID-LATE AFTERNOON, AND ALL THE
MESOSCALE AND STORM SCALE MODELS (NAM12, WRF-ARW, WRF-NMMB, RAP13,
AND EVEN THE 13-15HR VALID TIMES OF THE LATEST HRRR) SHOW SOME
SEMBLANCE OF CONVECTION INITIATING SOMEWHERE ACROSS THE WESTERN SIX
COUNTIES (HAMILTON-MORTON-STANTON-KEARNY-GRANT-STEVENS), SO WE WILL
INTRODUCE SOME 20-30 POPS IN THIS AREA. GIVEN THE SIGNIFICANT
TEMPERATURE-DEWPOINT SPREADS WITH TEMPS IN THE UPPER 90S/100 AND
DEWPOINTS IN THE LOW TO MID 50S, DRY MICROBURSTS ARE CERTAINLY GOING
TO BE THE GREATEST THREAT FROM CONVECTION...ESPECIALLY ON THE NORTH
SIDE OF CONVECTION WITH OUTFLOW WIND ADDING TO THE BACKGROUND STRONG
SYNOPTIC WINDS (WHICH OUTSIDE OF STORMS WILL BE 20 TO 25 KNOTS
SUSTAINED). GIVEN THE LACK OF ANY LARGE SCALE FORCING FOR ASCENT,
ANY CONVECTION WHICH DEVELOPS SHOULD DISSIPATE NOT TOO LONG AFTER
SUNSET. ANOTHER MILD NIGHT IS FORECAST TONIGHT INTO EARLY THURSDAY
MORNING WITH CONTINUED SOUTH WINDS OF 14 TO 17 KNOTS. THIS WILL KEEP
THE BOUNDARY LAYER MIXED THROUGH THE NIGHT WITH LOWS ONLY DOWN TO 70-
73F FOR MUCH OF SOUTHWEST AND SOUTH CENTRAL KANSAS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 353 AM CDT WED SEP 3 2014
OVERALL EXPECTATIONS FOR THE EXTENDED PERIOD FORECAST HAVE NOT
CHANGED IN THE LAST DAY, HOWEVER THE SENSIBLE WEATHER IMPACTS MAY
BECOME MORE CLEAR WITH TIME. THURSDAY WILL STILL BE A WARM DAY WITH
SOUTHERLY, SLIGHTLY DOWNSLOPE COMPONENT BREEZY CONDITIONS IN ADVANCE
OF AN APPROACHING COLD FRONT WHICH MAY INFLUENCE THE EXTREME WEST
CENTRAL COUNTIES DURING THE DAY. AGAIN THE NAM WAS FOLLOWED FAIRLY
CLOSE FOR THIS DAY WITH RESPECT TO HIGHS AND CLOUD COVER.
THUNDERSTORMS WILL BECOME A THREAT INTO THE EVENING AS THE FRONT
MOVES THROUGH THE AREA, BUT AGAIN UPPER SUPPORT IS SOMEWHAT LACKING.
POP TRENDS ARE INCREASING INTO THE SATURDAY PERIOD AS WELL AS THE
UPPER WAVE EJECTS ACROSS THE NORTHERN PLAINS, WHICH WILL INCREASE
MID LEVEL BAROCLINICITY ACROSS THE CENTRAL HIGH PLAINS. NAM MODEL
SATURATES THE BOUNDARY LAYER NICELY WITH SOME ELEVATED CAPE AND
UPSLOPE SURFACE FLOW SUGGESTING SHOWERS THUNDERSTORMS AND PROBABLY
FOG DEVELOPMENT AS WELL OVERNIGHT FRIDAY INTO SATURDAY MORNING.
FRIDAY AND SATURDAY WILL BE RELATIVELY COOL DAYS, WHILE CLOUDS AND
SHOWERS/ISOLATED THUNDERSTORMS MAY LINGER INTO SATURDAY EVENING IN
THE SOUTHERN COUNTIES. SHORTWAVE ENERGY IS SHOWN BY THE GFS TO
SPREAD ACROSS THE HIGH PLAINS AGAIN BY MONDAY, BRINGING ADDITIONAL
CHANCES FOR CONVECTION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1259 AM CDT WED SEP 3 2014
THE AVIATION FORECAST THROUGH 12-15Z TIME FRAME WEDNESDAY WILL BE
CHALLENGING. WE WILL MAINTAIN THE PESSIMISTIC FORECAST OF CEILING
FALLING TO AROUND 200-300 FEET AT GCK AND DDC STARTING AROUND 10Z.
THE LIFR CONDITIONS SHOULD EXIST FOR AT LEAST A COUPLE HOURS
BEFORE DRIER AIR MOVES IN FROM THE SOUTHWEST AS LOW LEVEL
SOUTHWEST MOMENTUM INCREASES BY DAYBREAK. FOR NOW, WE WILL KEEP
HYS AWAY FROM THE IFR/LIFR CONDITIONS, BUT THIS IS ALSO A LOW
CONFIDENCE FORECAST WITH AMENDMENTS QUITE POSSIBLE. SOUTHWEST
WINDS WILL INCREASE DURING THE LATE MORNING THROUGH MIDDAY TIME
FRAME, GUSTING TO 30+ KNOTS BY AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 97 72 96 64 / 10 10 10 40
GCK 98 70 97 61 / 10 30 20 40
EHA 99 68 96 63 / 20 20 10 60
LBL 100 71 97 66 / 10 20 0 40
HYS 98 72 97 61 / 10 10 20 50
P28 97 74 98 70 / 10 10 0 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RUSSELL
SHORT TERM...UMSCHEID
LONG TERM...RUSSELL
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS CARIBOU ME
939 AM EDT WED SEP 3 2014
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION THIS MORNING. HIGH PRESSURE
WILL BUILD ACROSS THE REGION LATER TODAY INTO THURSDAY. THE NEXT
COLD FRONT WILL MOVE THROUGH FRIDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
935 AM UPDATE...THE COLD FRONT HAS PUSHED OFFSHORE, AND THE HEAVY
PRECIPITATION THAT AFFECTED THE REGION EARLY THIS MORNING HAS
EXITED INTO CANADA. WHILE DRIER AIR IS WORKING INTO THE REGION,
THERE IS ALSO A WEAK SHORTWAVE IN THE FLOW ALOFT WHICH WILL TREK
ACROSS NORTHERN MAINE THIS AFTERNOON. THIS COMBINED WITH SOME
HEATING COULD BE ENOUGH TO ALLOW CUMULUS AND EVEN A FEW SHOWERS TO
DEVELOP THIS AFTERNOON, MAINLY ACROSS NORTHERN AROOSTOOK COUNTY.
THE HRRR MODEL BACKS UP THIS THINKING. ELSEWHERE, EXPECT JUST
PARTLY TO MOSTLY SUNNY SKIES. HAVE UPDATED THE FORECAST TO
INTRODUCE A SLIGHT CHANCE OF A SHOWER AND ADJUST CLOUD COVER.
OTHERWISE, NO OTHER CHANGES WERE NEEDED.
PREVIOUS DISCUSSION...A COLD FRONT IS CURRENTLY MOVING ACROSS THE REGION. A
LINE OF SHOWERS AND SOME THUNDERSTORMS IS ACCOMPANYING THIS SYSTEM
AS IT MOVES ACROSS THE STATE. BOTH THE NAM AND GFS ARE DOING A
GOOD JOB WITH BOTH PRECIPITATION AND TIMING... SO WILL USE A MODEL
CONSENSUS APPROACH AND BLEND THESE MODELS FOR POP...QPF AND SKY
COVER. BEHIND THE FRONT DRIER CONDITIONS AND A COLDER AIR MASS
WILL MOVE IN FROM HE WEST ALONG WITH STRONG HIGH PRESSURE. BASED
ON VERIFICATION OVER LAST 24 HOURS HAVE USED THE BIAS CORRECTED
RAW BLEND FOR MAXIMUM AND MINIMUM TEMPERATURE AND DEWPOINT.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
HIGH PRES WILL GRAB CONTROL OF THE REGION`S WX RIGHT THROUGH THIS
TERM WITH A COLD FRONT APPROACHING THE REGION FROM THE WEST LATER
IN THE DAY ON FRIDAY. UNTIL THEN, IT LOOKS LIKE WARM TEMPERATURES
FOR EARLY SEPTEMBER W/DAYTIME HIGHS ON THURSDAY IN THE UPPER 70S
TO AROUND 80 WITH EVEN WARMER READINGS ON FRIDAY. WE ARE TALKING
LOW TO MID 80S FOR AFTERNOON HIGHS ON FRIDAY AS A SSW WIND TAKES
HOLD AHEAD OF THE APPROACHING COLD FRONT.
AS FAR AS PRECIP CHANCES, DECIDED TO STAY W/THE DAYCREW`S THINKING
OF DRY CONDITIONS FOR THURSDAY W/A CHANCE OF SHOWERS(30-40%) BY LATE
FRIDAY AFTERNOON AND THIS WILL MAINLY BE ACROSS THE FAR W AND NW
AREAS. SOME OF THE INSTABILITY PARAMETERS SUCH AS 0-6KM SHEAR,
PWATS 1.5+" AND AN INVERTED V TYPE SOUNDING SUGGEST THE THREAT FOR
TSTMS. 0-6KM SHEAR IS FORECAST FROM BOTH THE NAM AND GFS TO BE
AROUND 35 KTS W/GOOD DIRECTIONAL AND SPEED SHEAR NOTED. DECIDED TO
KEEP THE MENTION OF TSTMS IN THERE FOR LATE FRIDAY AFTERNOON. THE
DAYCREW CAN ASSESS THIS FURTHER W/THE LATER MODEL GUIDANCE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE COLD FRONT IS FORECAST TO MOVE ACROSS THE REGION FRIDAY NIGHT
AND STALL ACROSS THE DOWNEAST REGION ON SATURDAY INTO SATURDAY
NIGHT AS IT BECOMES ALIGNED W/THE UPPER FLOW. A WEAK SURFACE LOW
IS SHOWN BY THE GFS AND ECMWF TO DEVELOP ON THE FRONT WHICH WOULD
KEEP THE RAIN GOING A WHILE LONGER. THE ECMWF IS FURTHER N W/THE
RAIN SHIELD WHILE THE GFS AND ITS ENSEMBLE KEEP THE RAIN ACROSS
THE CENTRAL AND DOWNEAST REGION. DECIDED ON A CONSENSUS FOR THIS
CYCLE YIELDING 60% FOR SHOWERS/RAIN ACROSS THE DOWNEAST AND COAST
AND 20-40% FURTHER N.
A COOLER AIRMASS IS EXPECTED SUNDAY INTO EARLY NEXT WEEK AS HIGH
PRES SLIDE SE FROM CENTRAL CANADA. IT WILL BE A NOTICEABLE CHANGE
AS DAYTIME TEMPERATURES ARE FORECAST TO BE SOME 10-15 DEGREES
COOLER THAN THEY HAVE BEEN THIS WEEK.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: EXPECT IFR/MVFR CONDITIONS THIS MORNING AS SHOWERS AND
THUNDERSTORMS MOVE THROUGH WITH A COLD FRONT....IMPROVING TO VFR
LATER THIS MORNING AS HIGH PRESSURE AND DRIER AIR MOVES IN FROM
THE WEST.
SHORT TERM: VFR THURSDAY INTO FRIDAY. THE CAVEAT TO THIS WILL BE
THE POTENTIAL FOR SOME SHALLOW FOG ESPECIALLY THURSDAY MORNING
THANKS IN PART TO THE RAINFALL THAT OCCURRED EARLIER. SOME
TERMINALS ESPECIALLY THE NORTHERN SITES COULD SEE A PERIOD OF MVFR
OR PERHAPS IFR IN THE MORNING. PERIODS OF MVFR FOR THE NORTHERN
TAF SITES W/A COLD FROPA FRIDAY EVENING WHILE IFR/MVFR IS
POSSIBLE ACROSS KBGR AND KBHB FRIDAY NIGHT INTO SATURDAY.
&&
.MARINE...
NEAR TERM: HAVE USED THE NAM12 TO INITIALIZE THE SUSTAINED WIND
GRIDS. FOR WAVES: A SOUTHERLY FETCH CONTINUES TO DEVELOP ACROSS
THE GULF OF MAINE AHEAD OF AN APPROACHING COLD FRONT. MOST OF THIS
FETCH IS OVER THE GULF OF MAINE WHERE COLDER AIR TEMPERATURE IS
SUPPRESSING WIND SPEEDS REACHING SURFACE. THIS FETCH IS GENERATING
THE PRIMARY WAVE SYSTEM (SOUTH 3 FEET/7-8 SECONDS). WAVE MODELS
APPEAR TOO HIGH DUE TO BOUNDARY CONDITIONS... SO HAVE INITIALIZED
WAVES WITH NEAR SHORE WAVE MODEL AND WILL ADJUST LOWER BY 20
PERCENT. WAVE FIELD ALSO ACCOMPANIED BY SECONDARY WAVE GROUP FROM
SOUTHEAST 1 FOOT/9-10 SECONDS.
SHORT TERM: NO HEADLINES FORESEEN UNTIL LATER FRIDAY NIGHT INTO
SATURDAY W/ A COLD FRONT SLIDING ACROSS THE WATERS. ATTM, DECIDED
TO STAY W/GUSTS TO 25 KTS AND SEAS CLIMBING TO 6 FT BY EARLY
SATURDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS/MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...HASTINGS/MIGNONE/HEWITT
MARINE...HASTINGS/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS DULUTH MN
1009 AM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 950 AM CDT WED SEP 3 2014
UPDATED TO ADJUST POPS ALONG THE SOUTHERN BORDER OF THE FCST AREA
BASED ON NORTHERN EXTENT OF THE PRECIP AREA IN SOUTHERN MN. THERE
IS SOME BACK BUILDING OF THE AREA IN THE SOUTH SO THE QUESTION IS
HOW MUCH WILL THE AREA AFFECT NE MN AND MW WI. IF THERE IS A LONG
WENOUGH BREAK IN THE PRECIP...THIS COULD ALLOW HIGHER DEWPOINTS TO
MOVE UP INTO THE FORECAST AREA. THE SREF AND HRRR IS HINTING AT
SOME DEVELOPMENT ACROSS THE SOUTHERN COUNTIES OF THE FORECAST AREA
AND MOVING NORTH BUT NOT AS MUCH AS EARLIER MODELS THIS MORNING.
THE NEXT 2-4 HOURS WILL INDICATE HOW THE SOUTHERN PRCIP AREA IS
AFFECTING DEVELOPMENT IN THE NORTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT WED SEP 3 2014
THE FOCUS IS ON THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS
THIS AFTERNOON AND TONIGHT. AT THE TIME OF THIS WRITING...THE
STORM PREDICTION CENTER HAD A SLIGHT RISK OF SEVERE STORMS OVER
MOST OF THE FORECAST AREA TODAY...WITH EXCEPTION OF THE FAR NORTH.
THERE IS THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...HEAVY
RAINFALL...AND EVEN TORNADOES. THE RISK WAS FOR THE SW AND SOUTH
CENTRAL FORECAST AREA.
A LOW PRESSURE SYSTEM IN THE ROCKIES IS EXPECTED TO MOVE INTO THE
NORTHERN HIGH PLAINS THIS MORNING AND GRADUALLY ORGANIZE AS IT
MOVES INTO WESTERN SOUTH DAKOTA THIS AFTERNOON. THERE WILL BE WARM
AND MOIST SOUTHERLY FLOW OVER THE NORTHERN PLAINS AND UPPER
MIDWEST...INCLUDING THE NORTHLAND. THE MODELS ARE PRIMARILY
INDICATING THAT A WARM/STATIONARY FRONT WILL SET UP OVER EASTERN
NORTH DAKOTA AND NORTHERN MINNESOTA. THIS FRONT AND FRONTOGENESIS
ALOFT WILL CONTRIBUTE TO INCREASING CHANCES FOR SHOWERS AND STORMS
IN ITS AREA LATE THIS MORNING AND THIS AFTERNOON. SOME MODELS ARE
ALSO SUGGESTING ANOTHER BOUNDARY...IN THE FORM OF ANOTHER
WARM/STATIONARY FRONT...COULD SET UP ACROSS THE SOUTHERN FORECAST
AREA. THIS OTHER FRONT WILL ALSO AID THE DEVELOPMENT OF SHOWERS
AND STORMS. SOME MODELS PLACE MORE EMPHASIS ON THE NORTHERN
BOUNDARY AND RESULTING SHOWERS AND STORMS...WHILE OTHERS PLACE
MORE EMPHASIS ON THE SOUTHERN BOUNDARY. SINCE THERE COULD BE
INITIAL CAPPING ISSUES OVER THE SOUTHERN FORECAST AREA DUE TO WARM
AIR ALOFT...I HAVE PCPN INCREASING MORE RAPIDLY NEAR THE NORTHERN
BOUNDARY.
THE ENVIRONMENT WILL SUPPORT THE POTENTIAL FOR STRONG TO SEVERE
STORMS OVER MUCH OF THE FORECAST AREA. MIXED LAYER CAPE COULD
APPROACH OR EXCEED 2000 J/KG LATE THIS AFTERNOON AND EARLY THIS
EVENING...WITH THE HIGHER INSTABILITY OVER THE SW AND SOUTHERN
FORECAST AREA. THE COMBINATION OF THIS INSTABILITY AND AT LEAST
30 TO 45 KNOTS OF DEEP LAYER (0-6 KM) WIND SHEAR WILL SUPPORT THE
DEVELOPMENT OF ORGANIZED SUPERCELLS DURING THE LATE AFTERNOON AND
EARLY EVENING. THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE
AREAS OF NE MINNESOTA SOUTH OF HIGHWAY 2...INCLUDING THE BRAINERD
LAKES REGION...WHERE INSTABILITY WILL LIKELY BE GREATEST WITH
SUFFICIENT SHEAR AND LOCATED NEAR THE SOUTHERN BOUNDARY. THIS IS
WHERE THERE WILL ALSO BE AN INCREASED POTENTIAL FOR TORNADOES.
MOST OF THE MODELS SUGGEST THAT AFTER THE INITIAL HOURS OF
CONVECTION LATE THIS AFTERNOON AND EARLY THIS EVENING...THAT THE
STORMS COULD FORM A COMPLEX WHICH WOULD LIKELY MOVE EAST...TAPPING
INTO THE STRONG INSTABILITY AND 850 HPA FLOW AND MOISTURE
TRANSPORT ACROSS THE SOUTHERN FORECAST AREA. WHILE THE INITIAL
THREAT OF TODAY MAY BE LARGE HAIL AND TORNADOES...THIS WOULD
PROBABLY TRANSITION TO MORE OF A THREAT OF DAMAGING WINDS. THE
PRECIPITABLE WATER VALUES...WHICH COULD REACH THE 1.75 TO 2 INCH
RANGE...ALSO SUPPORT POTENTIAL HEAVY RAIN. SOME AREAS COULD SEE A
QUICK 1 TO 2 INCHES OF RAIN DEPENDING ON THE DEVELOPMENT AND TRACK
OF STORMS.
THE CHANCES OF SHOWERS AND STORMS WILL DECREASE FROM WEST TO EAST
OVERNIGHT AS AXIS OF THE LOW JET...AND THE MOISTURE TRANSPORT
AXIS...SHIFTS TO THE EAST. THE SURFACE LOW IN WESTERN SOUTH DAKOTA
WILL MOVE TO THE SD/MN BORDER BY LATE IN THE NIGHT...AND ITS
INVERTED TROUGH WILL MOVE TO NEAR THE ND/MN BORDER. THERE ARE LOW
CHANCES OF LINGERING SHOWERS AND STORMS OVER THE FAR NW FORECAST
AREA DUE TO THE LINGERING SUBTLE BOUNDARY OVER NORTHERN MINNESOTA
OR NW ONTARIO AND RESIDUAL FRONTOGENESIS ALOFT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 350 AM CDT WED SEP 3 2014
INITIAL FOCUS FOR LONG TERM IS THE TIMING OF THE COLD FRONT
PASSAGE AND TSTM POTENTIAL THURSDAY. HAVE MADE MINOR ADJUSTMENTS
TO PREVIOUS FCST TO REFINE TIMING OF THE WIND SHIFT/POPS FOR A
SLIGHTLY SLOWER FROPA. LATEST ECM/NAM/GFS ARE ALL IN GOOD
AGREEMENT THE COLD FRONT/SFC LOW REACHES THE WRN MN BORDER
THURSDAY MORNING AROUND DAYBREAK...TRACKS EAST ACROSS NORTH-
CENTRAL MINNESOTA THROUGH THE EARLY AFTERNOON...REACHING LOCATIONS
ALONG A LINE FROM KHIB/KDLH/K04W AROUND 00Z...THEN QUICKLY PASSES
OVER THE NRN WISCONSIN ZONES BY MIDNIGHT.
THIS TIMING WILL POSITION MUCH OF THE FORECAST AREA IN THE WARM
SECTOR WITH INCREASING MOISTURE/DEW POINTS FOR MUCH OF THE DAY
THURSDAY. LATEST GUIDANCE SUGGESTS DEW POINTS REACH THE LOW 70S
ACROSS THE ST CROIX RIVER VALLEY AND ACROSS NORTHERN WISCONSIN. IN
ADDITION...THE RESULTING PRESSURE GRADIENT DUE TO THE APPROACHING
FRONT WILL PROMOTE EAST WINDS OVER LAKE SUPERIOR. HAVE LOWERED
TEMPS AND INTRODUCED AREAS OF FOG FOR LOCATIONS ALONG THE NORTH
SHORE AND WESTERN TIP OF LAKE SUPERIOR TO ACCOUNT FOR THE MARINE
AIR MASS.
THE STRONG BAROCLINIC ZONE AND ABUNDANT MOISTURE WILL SUPPORT
STRONG TO SEVERE THUNDERSTORMS ALONG THE FRONT...MAINLY DURING
THE AFTERNOON/EVENING HOURS THURSDAY. HOWEVER...THE LIMITING
FACTOR WILL BE THE NORTHERN EXTENT OF A A STRONG MID-LEVEL CAP.
LATEST NAM BUFR SOUNDING AT KBRD SHOWS H700-H800 TEMPS AROUND 15C.
FURTHER NORTH...TOWARDS KHIB/KELO TEMPERATURES ARE COOLER...BUT
STILL INTRODUCE A LEVEL OF UNCERTAINTY IN THE ABILITY TO TRIGGER
CONVECTION.
IN THE WAKE OF THE COLD FRONT...H85 WINDS ON THE ORDER OF 30-40 KT
WILL ALLOW MUCH COOLER AND DRIER AIR TO SURGE INTO THE
NORTHLAND. THE COLD AIR ALOFT WILL ALLOW FOR FAVORABLE LOW LEVEL
LAPSE RATES THURSDAY NIGHT TO MAINTAIN A FEW THOUSAND FT MIXED
LAYER. HAVE INCREASED WINDS/GUSTS THURS NIGHT AND MAY NEED TO BE
FURTHER INCREASED ON LATER SHIFTS. AT THIS TIME...A PERIOD OF
WINDS GUSTING AROUND 30-35 KT THURSDAY NIGHT IS EXPECTED OVER MUCH
OF THE DLH FORECAST AREA/LAKE SUPERIOR. THE HIGHEST WIND GUSTS ARE
ANTICIPATED ALONG THE NORTH SHORE OF LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 650 AM CDT WED SEP 3 2014
A WARM FRONT WILL LIFT OVER THE FORECAST AREA TODAY...BRINGING
LOWERING CEILINGS AND INCREASING THUNDER CHANCES THROUGH THE
AFTERNOON AND EVENING. BY 06Z...WIDESPREAD MVFR/IFR CONDITIONS
WILL BE FOUND AFTER 06Z AS LOW CLOUDS AND SCATTERED SHOWERS AND
THUNDERSTORMS ARE FOUND ACROSS THE REGION. HAVE BROUGHT IN LIFR
CONDITIONS TO KDLH AFTER 06Z...AS WINDS TURN OUT OF THE EAST AND
ELEVATED DEW POINTS ALLOW FOR FOG/-DZ.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 75 62 70 55 / 60 70 40 10
INL 76 57 72 46 / 40 50 50 30
BRD 78 64 76 50 / 70 80 20 20
HYR 78 66 83 52 / 40 80 60 20
ASX 79 63 81 53 / 50 70 70 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
UPDATE...STEWART
SHORT TERM...GROCHOCINSKI
LONG TERM...GRANING
AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS HASTINGS NE
639 AM CDT WED SEP 3 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM CDT WED SEP 3 2014
UPPER AIR AND SATELLITE DATA SHOWING THE AREA CONTINUING TO BE
INFLUENCED BY ZONAL FLOW...AS HIGH PRESSURE EXTENDS ACROSS THE SRN
CONUS AND BROAD TROUGHING IS IN PLACE NEAR/NORTH OF THE CANADIAN
BORDER...THOUGH AN AREA OF LOW PRESSURE IS PUSHING ITS WAY FURTHER
INLAND FROM THE PAC NW COAST. AS WAS SHOWN BY MODELS...CONVECTION
DEVELOPED EARLIER ACROSS CENTRAL KANSAS...IN RESPONSE TO A WEAK
DISTURBANCE AS WELL AS INCREASED LIFT VIA WARM AIR/MOISTURE
ADVECTION ASSOCIATED WITH A STRONGER LLJ. EARLY ON THE FAR
SOUTHEASTERN CORNER OF MITCHELL COUNTY WAS CLIPPED BY THIS
ACTIVITY...BUT SINCE THEN HAS REMAINED OVER ERN KS. THERE IS A
COUPLE ISOLATED SHOWERS OVER WESTERN KS...AND THE HRRR/RAP HINT AT
SOME ADDITIONAL ACTIVITY POSSIBLY LINGERING INTO THE MID MORNING
HOURS...SO WILL HAVE TO MONITOR HOW THIS ACTIVITY EVOLVES OVER
NEXT FEW HOURS. SATELLITE IMAGERY ALSO SHOWING SOME LOW/MID LEVEL
STRATUS STARTING TO INCREASE IN COVERAGE...BUT MODELS DIFFER SOME
ON HOW EXPANSIVE IT WILL END UP BEING. AT THE SURFACE...THE CWA IS
SET UP BETWEEN HIGH PRESSURE AFFECTING MUCH OF THE ERN CONUS...AND
A TROUGH OF LOW PRESSURE OVER THE HIGH PLAINS. WINDS REMAIN
SOUTHERLY...WITH SPEEDS RANGING FROM 5 TO 15 MPH. TEMPS ARE MORE
MILD THAN 24 HRS AGO...WITH 3 AM TEMPS IN THE MID 60S TO LOWER
70S.
THE MAIN STORY IN THE SHORT TERM PERIOD LIES WITH
TEMPERATURES...AS TODAY IS EXPECTED TO BE THE WARMEST OVER THE
NEXT 7. IN THE UPPER LEVELS...MODELS IN GOOD AGREEMENT SHOWING THE
FLOW TRANSITIONING TO MORE SOUTHWESTERLY AS THAT ABOVE MENTION PAC
NW DISTURBANCE SHIFTS FURTHER EASTWARD INTO THE NRN ROCKIES. WHILE
NOT EXPECTING MUCH IN THE WAY OF PRECIP CHANCES THROUGH TONIGHT
/THOUGH CHANCES ARE NOT ZERO/...THIS PATTERN WILL HELP TO CONTINUE
THE ADVECTION OF WARMER AIR ALOFT INTO THE REGION. THIS WILL
CONTINUE RIGHT ON INTO THE OVERNIGHT HOURS AS THE ASSOCIATED SFC
COLD FRONT CREEPS IN FROM THE WEST. BY SUNRISE THURS...MODEL
TIMING ISNT BAD...SHOWING THE FRONT DRAPED ACROSS THE NWRN CORNER
OF THE CWA.
TEMPERATURES FOR TODAY ARE A LITTLE TRICKY...AS SOME MODELS
SHOWING POOLING OF MOISTURE/HIGHER DPTS IN THE SOMEWHAT USUAL
PLACES FOR OUR CWA...ROUGHLY THE NERN THIRD OR SO...WITH DPTS IN
THE LOWER 70S. THOSE HIGHER DPTS MAY KEEP TEMPS DOWN A TOUCH IN
THOSE AREAS...AND HAVE FORECAST HIGHS RIGHT AROUND 90. FURTHER
SW...THINKING THAT TEMPS WILL REACH INTO THE MID/UPPER 90S WITH
DPTS IN THE LOWER 60S. NOT BUYING INTO THE RAP WHICH IS SHOWING
LOW/MID 50S BY MID AFTERNOON DOWN THERE...WITH TEMPS THEN CLIMBING
INTO THE LOW 100S. SOMETHING FOR THE DAY SHIFT TO WATCH THOUGH. AS
WE GET INTO TONIGHT...WITH THE CONTINUED SOUTHERLY FLOW EXPECTED
THROUGH THE MAJORITY OF THE NIGHT...OVERNIGHT LOWS LOOK TO REMAIN
MILD IN THE MID 60S TO MID 70S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 417 AM CDT WED SEP 3 2014
MAIN ISSUE WILL BE POTENTIAL FOR PRECIPITATION.
WE BEGIN THE LONG TERM ON THURSDAY UNDER UPPER LEVEL SOUTHWEST
FLOW WITH A SUBTROPICAL HIGH IN THE SOUTHEASTERN UNITED STATES.
AND A POSITIVELY TILTED TROUGH OVER THE NORTHWESTERN UNITED
STATES.
MOST IF NOT ALL OF THURSDAY SHOULD BE DRY...DESPITE A SURFACE COLD
FRONT MAKING ITS WAY SLOWLY SOUTH AS NUMERICAL MODELS CONTINUE
TO SHOW POST-FRONTAL PRECIPITATION DEVELOPING MAINLY THURSDAY
EVENING CLOSER TO THE VICINITY OF THE UPPER LEVEL JET
STREAK...WHICH WILL NUDGE SOUTH OVER TIME...AND IN TURN PUSHING
THE COLD FRONT FARTHER SOUTH.
INSTABILITY EVENTUALLY WANES AND THERE WILL BE LESS OF A
THUNDERSTORM CHANCE HEADING INTO FRIDAY AND TOOK OUT THUNDER BY
LATE EVENING FRIDAY NIGHT INTO SATURDAY.
THE FRONT IS STILL EXPECTED TO MAKE A RETURN AS THE SURFACE HIGH
THAT HELPED PUSH THE COLD FRONT SOUTH...MAKES A FAIRLY QUICK
RETREAT TO THE EAST...ALLOWING THE FRONT TO RETURN NORTH AS A
WARM FRONT.
ANOTHER COLD FRONT TUESDAY AFTERNOON/NIGHT WILL BRING IN SOME
COOLER WEATHER FOR WEDNESDAY.
THERE COULD BE ENOUGH OF A COMBINATION OF SHEAR AND INSTABILITY
FOR STRONG TO SEVERE THUNDERSTORMS ANYWHERE FROM SUNDAY NIGHT
INTO TUESDAY...BUT IT WOULD BE A TOUGH CALL TO NAIL ANYTHING DOWN
RIGHT NOW.
FOR TEMPERATURES...I WENT WITH CONSRAW FOR LOWS THURSDAY NIGHT AND
FRIDAY NIGHT. NAM FOR HIGHS THURSDAY AND BCCONSRAW FOR HIGHS
FRIDAY...WHICH ARE CONSIDERABLY COOLER. IN FACT...FRIDAY SHOULD
FEEL RATHER FALL-LIKE. OTHER NUMERICAL MODEL SOLUTIONS HAVE NOT
CAUGHT ON LIKE THE BCCONSRAW HAS...BUT I STRONGLY SUSPECT THAT
THEY WILL SOON...CONSIDERING THE TRACK RECORD OF THIS SOLUTION THE
DAY AFTER A COLD FRONT PASSAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 635 AM CDT WED SEP 3 2014
MAIN FORECAST CONCERN COMES THIS MORNING...AS RESTRICTIONS WITH AT
LEAST CEILINGS SEEMS LIKELY AS AN AREA OF LOW LEVEL STRATUS
EXPANDS ACROSS THE AREA. SURROUND OBS SHOWING CEILINGS LESS THAN
1000FT...AND HAVE THOSE CONDITIONS IN AT BOTH TERMINALS THROUGH
MID MORNING...LIFTING A BIT FOR THE LATE MORNING HOURS. MODELS
SUGGEST VFR CONDITIONS ARE EXPECTED TO RETURN THIS
AFTERNOON...WILL SEE HOW THAT PANS OUT. ADJUSTMENTS TO THE TIMING
OF CEILING IMPROVEMENTS MAY BE NEEDED. ONGOING PRECIPITAITON
SLIDING IN FROM THE WEST AT THIS POINT LOOKS TO REMAIN SOUTH OF
THE TERMINAL AREAS. WINDS THROUGH THE PERIOD WILL REMAIN
SOUTHERLY...INCREASING WITH TIME...WITH SPEEDS THIS AFTERNOON IN
THE 15 TO 25 MPH RANGE...GUSTS NEAR 30 MPH POSSIBLE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...ADO
LONG TERM...HEINLEIN
AVIATION...ADO
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1055 AM EDT WED SEP 3 2014
.SYNOPSIS...A SURFACE TROUGH WILL BE LOCATED OVER CENTRAL NORTH
CAROLINA THIS AFTERNOON AS A COLD FRONT REMAINS JUST TO OUR NORTH.
HIGH PRESSURE THEN WILL BUILD BACK OVER THE AREA FOR THE REMAINDER
OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM WEDNESDAY...
THE LATEST SURFACE ANALYSIS SHOWED A SURFACE FRONT OVER NORTHERN
VIRGINIA WITH SURFACE TROUGHS CLOSE TO THE VIRGINIA BORDER EXTENDING
WEST TO EAST...AND OVER THE WESTERN PART OF CENTRAL NORTH CAROLINA.
WIND SHEAR WAS WEAK AND SHOULD REMAIN SO THROUGH THE REST OF THE
DAY...WITH RAP FORECAST 0-3KM VALUES ON THE ORDER OF 10KT OR LESS.
THE LATEST SPC MESOANALYSIS SHOWED GOOD CIN OVER THE WESTERN
PIEDMONT WITH INSTABILITY...TO 2000J/KG...ALONG THE IMMEDIATE COAST.
THE RAP FORECASTS THIS CIN...ASSOCIATED WITH A LOW-LEVEL CAP AND
GOOD DEW POINT SPREADS SUCH AS NOTED ON THE 12Z KGSO SOUNDING...
ERODING THIS AFTERNOON AROUND 20Z. WHILE IN THE MID-LEVELS THERE
SHOULD BE A WEAK SHEAR AXIS AND VORTICITY CLOSER TO THE VIRGINIA
BORDER THIS AFTERNOON...BETTER LOW-LEVEL FORCING IS EXPECTED IN
SURFACE TROUGHINESS CLOSER TO THE COASTAL PLAIN WHERE THE
INSTABILITY SHOULD ALSO BE GREATER...ON THE ORDER OF 1500J/KG THIS
AFTERNOON BASED ON RAP SOUNDINGS. THE RAP FORECASTS THE BETTER LIFT
IN THAT AREA AS WELL...GRADUALLY PROPAGATING WEST IN THE LIGHT WINDS
AND WEAK SHEAR. THE VARIETIES OF HRRR WRF GUIDANCE LEAN TOWARD
INITIAL DEEP CONVECTIVE DEVELOPMENT TOWARD INTERSTATE 95 GRADUALLY
PROPAGATING NORTHWEST...STRUGGLING TO MAKE IT INTO THE TRIAD WHERE
OVERALL STABILITY SHOULD BE GREATER. FOR THE MORNING UPDATE...
DELAYED THE ONSET OF ISOLATED TO SCATTERED POPS AND TRENDED ANY TO
LATE IN THE DAY AND INTO THIS EVENING OVER THE NORTHWEST PIEDMONT.
GIVEN DCAPE FORECAST AT A MAXIMUM AROUND 700J/KG THIS AFTERNOON...
AN ISOLATED STORM COULD PRODUCE A STRONG WIND GUST...BUT INSTANCES
OF SUCH SHOULD BE PULSE-LIKE IN WEAK SHEAR AND WEAK WINDS ALOFT.
WITH GOOD SUN THROUGH THE MORNING AND A FAST RISE TO TEMPERATURES...
IN SEVERAL LOCATIONS RAISED MAXES A DEGREE OR TWO...FOR HIGHS OF 90
TO 95. APPARENT TEMPERATURES...LIKE IN THE HWO...SHOULD BE WITHIN
A DEGREE OR TWO OF 100 EAST OF ABOUT U.S. 1.
CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE
COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO
SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER
60S AND LOWER 70S.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 305 AM WEDNESDAY...
THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A
SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS
HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE
AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION
SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR
SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED
COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL
THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH
NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL
INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN
THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 330 AM WEDNESDAY...
THE SUB-TROPICAL RIDGE WILL BRIEFLY EXPAND NORTH INTO THE OH VALLEY
AND MIDDLE ATLANTIC...AND CONSEQUENTLY CAUSE THE MID LEVEL SHEAR AND
MOIST AXIS SETTLING INTO CENTRAL NC THIS MORNING...TO WEAKEN AND BOW
NORTH INTO VA FRI-SAT. MEDIUM RANGE ENSEMBLE GUIDANCE SUGGESTS THE
SUB-TROPICAL RIDGE WILL THEN WEAKEN AND BECOME SUPPRESSED...BY A
PAIR OF SHORTWAVE TROUGHS FORECAST TO CROSS THE NE US AND SE CANADA
IN PROGRESSIVE FLOW ALOFT THROUGH THE END OF THE WEEKEND. GUIDANCE
IS ALSO IN AGREEMENT THAT SOME DEGREE OF TROUGHING WILL BE LEFT
BEHIND IN A POSITIVE TILT FASHION OVER THE MIDDLE ATLANTIC...THOUGH
THE DEGREE OF WHICH REMAINS UNCERTAIN DUE TO ABOVE AVERAGE MODEL
SPREAD OF THE H5 PATTERN BY DAYS 6-7 (MON-TUE). THE EBB AND FLOW OF
THE PATTERN ALOFT...AND ASSOCIATED SUPPRESSION OF THE SUB-TROPICAL
RIDGE...WILL ALLOW THE POLAR FRONT TO SETTLE SE THROUGH CENTRAL NC
CENTERED AROUND THE DAY SUNDAY...BEFORE SLOWING AS IT DRIFTS
OFFSHORE AND INTO THE VICINITY OF THE GULF STREAM THROUGH MID-WEEK.
A WEAK WAVE OF LOW PRESSURE...OR TWO...ARE APT TO DEVELOP ALONG THE
SLOWING FRONT...AS THE AFOREMENTIONED POSITIVELY TILTED TROUGH ALOFT
INTERACTS WITH SEASONABLY STRONG BAROCLINICITY DRIVEN BY THE
INCOMING COOL/DRY CANADIAN AIR MASS INTO THE WARM/MOIST GULF STREAM
WATERS.
FRI-SAT: A PATTERN OF WEAK SYNOPTIC-SCALE ASCENT AHEAD OF THE
AFOREMENTIONED POLAR FRONT WILL FAVOR NEAR CLIMO PROBABILITIES OF
DIURNALLY-DRIVEN CONVECTION ALONG THE SEA BREEZE AND MOUNTAINS...
BOTH OF WHICH WILL BE APT TO PROPAGATE INTO THE WESTERN AND EASTERN
EDGES OF THE RAH CWFA EACH AFTERNOON AND EVENING. THE DISSIPATION
AND NORTHWARD DEPARTURE OF MID-HIGH CLOUDINESS ASSOCIATED WITH THE
AFOREMENTIONED SHEAR AXIS ALOFT...RESULTING FROM THE BRIEFLY
BUILDING SUB-TROPICAL RIDGE...SHOULD ALLOW FULL-SUN (OR NEARLY SO)
H85 TEMPS IN THE 17-18C RANGE TO BE REALIZED...SUPPORTIVE OF HIGHS
OF 88 TO 93 DEGREES. SAT NIGHT-SUN: THE BEST CHANCE OF SHOWERS AND
STORMS DURING THE LONG TERM PERIOD WILL UNDOUBTEDLY ACCOMPANY THE
ARRIVAL/PASSAGE OF THE POLAR FRONT...ONE WHOSE LOW LEVEL FRONTAL
CIRCULATION WILL BE SUPPORTED THROUGH THE MID-UPPER LEVELS BY
PERSISTENT RIGHT ENTRANCE REGION UPPER JET FORCING. THE COMBINATION
OF INCREASING MID-HIGH CLOUDS AND NUMEROUS TO WIDESPREAD SHOWERS AND
STORMS SHOULD HOLD TEMPERATURES GENERALLY IN THE LOWER TO MIDDLE
80S.
SUN NIGHT-MON NIGHT: SUBSIDENCE DRYING AND LESSENING PROBABILITIES
OF RAIN WILL DEVELOP FROM NW TO SE...BUT NORTHEASTERLY LOW-MID LEVEL
FLOW ON THE WEST SIDE OF THE FRONTAL ZONE AND PROBABLE WAVES OF LOW
PRESSURE WILL RESULT IN MOSTLY CLOUDY CONDITIONS AND A CHANCE OF
RAIN OVER THE EASTERN CWFA...RANGING TO PARTIAL SUNSHINE AND
GENERALLY DRY CONDITIONS OVER THE WESTERN PIEDMONT. COOLER WITH
HIGHS IN THE UPPER 70S TO LOWER 80S.
TUE: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE NORTHEASTERLY
FLOW...AND INCREASING AMOUNTS OF SUNSHINE. MILD WITH HIGHS AGAIN IN
THE UPPER 70S TO LOWER OR PERHAPS MIDDLE 80S.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1055 AM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THIS AFTERNOON THROUGH THIS
EVENING OUTSIDE OF DEEP CONVECTION. SHOWERS AND STORMS ARE EXPECTED
TO DEVELOP BY THIS AFTERNOON IN THE VICINITY OF A SURFACE TROUGH
OVER THE AREA. WEAK STEERING FLOW AND THE POTENTIAL FOR VARIOUS
OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME CONVECTION AT ANY
SPECIFIC TAF SITE...BUT THE PRESENCE OF THE TROUGH LENDS BETTER
CHANCES TO KFAY...KRWI AND KRDU. HOWEVER...CONFIDENCE IS FAIRLY HIGH
THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS AFTERNOON AND
EVENING. A LIGHT SOUTHERLY WIND IS EXPECTED TO REDEVELOP
TONIGHT...WHICH MAY INDUCE PATCHY STRATUS ACROSS THE AREA BY
THURSDAY MORNING.
OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING
STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING
COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE
THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF/BLS
SHORT TERM...BLS
LONG TERM...MWS
AVIATION...DJF/BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
730 AM EDT WED SEP 3 2014
.SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS
CENTRAL NC TODAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR
THE REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 305 AM WEDNESDAY...
A FEW SHOWERS POPPING UP ALONG REMNANT OUTFLOW FROM CONVECTION
CROSSING THE MOUNTAINS LATE LAST EVENING WILL CONTINUE TO MOVE OFF
TO THE NORTHEAST ACROSS THE NORTHERN PIEDMONT THIS MORNING.
LINGERING INSTABILITY AND RECENT RADAR TRENDS SUGGEST THAT A COUPLE
ISOLATED THUNDERSTORMS ARE POSSIBLE AS WELL. THE OUTLFOW WILL
SETTLE SOUTH THIS MORNING AND SHOULD PRETTY MUCH BISECT THE AREA
FROM SOUTHWEST TO NORTHEAST BASED ON THE LATEST RAP FORECAST. THERE
IS NO REAL AIRMASS CHANGE ACROSS THE AREA AND THE BLENDED TOTAL PW
PRODUCT SHOWS PW VALUES OF 1.8 TO 2 INCHES HIS MORNING. H85 TEMPS
ARE DOWN A COUPLE DEGREES FROM THE LATEST COUPLE OF DAYS AND HIGHS
SHOULD ONLY BE IN THE LOW TO MID 90S TODAY. HOWEVER..THE STRONG
HEATING COMBINED WITH THE MOIST AIRMASS WILL LEAD TO MODERATE
INSTABILITY AGAIN THIS AFTERNOON. LOW-LEVEL CONVERGENCE AND A
REMNANT DISTURBANCE/SHEAR AXIS ALOFT WILL SERVE AS A TRIGGER FOR
SCATTERED TO SOMETIMES NUMEROUS SHOWERS AND STORMS...AND WHILE
MOISTURE/INSTABILITY SHOULD FAVOR BETTER COVERAGE ACROSS THE
SOUTH...WEAK STEERING FLOW AND PROPAGATING OUTFLOWS MAKES IT
DIFFICULT TO ASSESS WHERE STORM COVERAGE WILL BE THE GREATEST. MOST
HIRES GUIDANCE SHOWS STORMS DEVELOPING ACROSS THE SOUTH BY 19Z AND
THEN SHIFTING NORTHWARD AS THE AFOREMENTIONED BOUNDARY WASHES OUT.
HEAVY RAIN...MINOR FLOODING AND A FEW STRONG WIND GUSTS WILL BE THE
MAIN STORM THREATS.
CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE
COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO
SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER
60S AND LOWER 70S.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 305 AM WEDNESDAY...
THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A
SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS
HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE
AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION
SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR
SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED
COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL
THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH
NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL
INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN
THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 330 AM WEDNESDAY...
THE SUB-TROPICAL RIDGE WILL BRIEFLY EXPAND NORTH INTO THE OH VALLEY
AND MIDDLE ATLANTIC...AND CONSEQUENTLY CAUSE THE MID LEVEL SHEAR AND
MOIST AXIS SETTLING INTO CENTRAL NC THIS MORNING...TO WEAKEN AND BOW
NORTH INTO VA FRI-SAT. MEDIUM RANGE ENSEMBLE GUIDANCE SUGGESTS THE
SUB-TROPICAL RIDGE WILL THEN WEAKEN AND BECOME SUPPRESSED...BY A
PAIR OF SHORTWAVE TROUGHS FORECAST TO CROSS THE NE US AND SE CANADA
IN PROGRESSIVE FLOW ALOFT THROUGH THE END OF THE WEEKEND. GUIDANCE
IS ALSO IN AGREEMENT THAT SOME DEGREE OF TROUGHING WILL BE LEFT
BEHIND IN A POSITIVE TILT FASHION OVER THE MIDDLE ATLANTIC...THOUGH
THE DEGREE OF WHICH REMAINS UNCERTAIN DUE TO ABOVE AVERAGE MODEL
SPREAD OF THE H5 PATTERN BY DAYS 6-7 (MON-TUE). THE EBB AND FLOW OF
THE PATTERN ALOFT...AND ASSOCIATED SUPPRESSION OF THE SUB-TROPICAL
RIDGE...WILL ALLOW THE POLAR FRONT TO SETTLE SE THROUGH CENTRAL NC
CENTERED AROUND THE DAY SUNDAY...BEFORE SLOWING AS IT DRIFTS
OFFSHORE AND INTO THE VICINITY OF THE GULF STREAM THROUGH MID-WEEK.
A WEAK WAVE OF LOW PRESSURE...OR TWO...ARE APT TO DEVELOP ALONG THE
SLOWING FRONT...AS THE AFOREMENTIONED POSITIVELY TILTED TROUGH ALOFT
INTERACTS WITH SEASONABLY STRONG BAROCLINICITY DRIVEN BY THE
INCOMING COOL/DRY CANADIAN AIR MASS INTO THE WARM/MOIST GULF STREAM
WATERS.
FRI-SAT: A PATTERN OF WEAK SYNOPTIC-SCALE ASCENT AHEAD OF THE
AFOREMENTIONED POLAR FRONT WILL FAVOR NEAR CLIMO PROBABILITIES OF
DIURNALLY-DRIVEN CONVECTION ALONG THE SEA BREEZE AND MOUNTAINS...
BOTH OF WHICH WILL BE APT TO PROPAGATE INTO THE WESTERN AND EASTERN
EDGES OF THE RAH CWFA EACH AFTERNOON AND EVENING. THE DISSIPATION
AND NORTHWARD DEPARTURE OF MID-HIGH CLOUDINESS ASSOCIATED WITH THE
AFOREMENTIONED SHEAR AXIS ALOFT...RESULTING FROM THE BRIEFLY
BUILDING SUB-TROPICAL RIDGE...SHOULD ALLOW FULL-SUN (OR NEARLY SO)
H85 TEMPS IN THE 17-18C RANGE TO BE REALIZED...SUPPORTIVE OF HIGHS
OF 88 TO 93 DEGREES. SAT NIGHT-SUN: THE BEST CHANCE OF SHOWERS AND
STORMS DURING THE LONG TERM PERIOD WILL UNDOUBTEDLY ACCOMPANY THE
ARRIVAL/PASSAGE OF THE POLAR FRONT...ONE WHOSE LOW LEVEL FRONTAL
CIRCULATION WILL BE SUPPORTED THROUGH THE MID-UPPER LEVELS BY
PERSISTENT RIGHT ENTRANCE REGION UPPER JET FORCING. THE COMBINATION
OF INCREASING MID-HIGH CLOUDS AND NUMEROUS TO WIDESPREAD SHOWERS AND
STORMS SHOULD HOLD TEMPERATURES GENERALLY IN THE LOWER TO MIDDLE
80S.
SUN NIGHT-MON NIGHT: SUBSIDENCE DRYING AND LESSENING PROBABILITIES
OF RAIN WILL DEVELOP FROM NW TO SE...BUT NORTHEASTERLY LOW-MID LEVEL
FLOW ON THE WEST SIDE OF THE FRONTAL ZONE AND PROBABLE WAVES OF LOW
PRESSURE WILL RESULT IN MOSTLY CLOUDY CONDITIONS AND A CHANCE OF
RAIN OVER THE EASTERN CWFA...RANGING TO PARTIAL SUNSHINE AND
GENERALLY DRY CONDITIONS OVER THE WESTERN PIEDMONT. COOLER WITH
HIGHS IN THE UPPER 70S TO LOWER 80S.
TUE: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE NORTHEASTERLY
FLOW...AND INCREASING AMOUNTS OF SUNSHINE. MILD WITH HIGHS AGAIN IN
THE UPPER 70S TO LOWER OR PERHAPS MIDDLE 80S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 730 AM WEDNESDAY...
ONCE THE BRIEF MVFR VSBYS AT KRWI IMPROVE...LIKELY BY 13Z...VFR
CONDITIONS ARE EXPECTED TO PREVAIL OUTSIDE OF CONVECTION. SHOWERS
AND STORMS ARE EXPECTED TO DEVELOP BY THIS AFTERNOON IN THE VICINITY
OF A SURFACE TROUGH OVER THE AREA. WEAK STEERING FLOW AND THE
POTENTIAL FOR VARIOUS OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME
CONVECTION AT ANY SPECIFIC TAF SITE...BUT THE PRESENCE OF THE TROUGH
LENDS BETTER CHANCES TO KFAY...KRWI AND KRDU. HOWEVER... CONFIDENCE
IS FAIRLY HIGH THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS
AFTERNOON/EVENING.
A LIGHT SOUTHERLY WIND IS EXPECTED TO REDEVELOP TONIGHT...WHICH MAY
INDUCE PATCHY STRATUS ACROSS THE AREA BY THURSDAY MORNING.
OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING
STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING
COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE
THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD/WSS
NEAR TERM...BLS
SHORT TERM...BLS
LONG TERM...MWS
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1011 AM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 1001 AM CDT WED SEP 3 2014
MAIN FOCUS REMAINS ON WHAT WILL HAPPEN LATER TODAY IN TERMS OF
SEVERE CONVECTION IN FAR NORTHEASTERN SD..WEST CENTRAL-CENTRAL MN
AND HOW FAR NORTH WILL IT REACH. INCOMING 12Z DATA FROM NAM AND
LATEST RAP/HRRR MODELS INDICATE ABOUT THE SAME SCENERIO WITH
EVENTUAL NORTHWARD ADVANCE OF CONVECTION ZONE THAT IS NOW FROM
BTWN BROOKINGS AND WATERTOWN SD TOWARD THE TWIN CITIES...WITH IT
REACHING NEAR THE SISSETON-ALEXANDRIA-LONG PRAIRIE MN LINE EARLY
TO MID AFTERNOON. HOWEVER HRRR MAY BE A TAD FAST IN SPREADING IT
NORTH AS ABUNDANCE OF CLOUD COVER MAY KEEP TRUE WARM FRONT A BIT
SOUTH YET OF PROGGED POSITION...WHICH FROM THE HRRR IS ROUGHLY NR
A WATERTOWN-WILMAR LINE AT 21Z. REGARDLESS...MAIN THREAT FOR ANY
PRECIP NOT REACHING THE FAR SOUTHEASTERN FCST TIL THIS AFTN WITH
INCREASING CHANCES BY LATE AFTN. RISK OF SEVERE THERE...THOUGH
HIGHEST SEVERE PARAMETERS REMAIN A TAD SOUTH. OTHERWISE DRY OVER
MUCH OF NW MN INTO ERN ND (OUTSIDE OF FAR SOUTHEASTERN CORNER).
MAIN UPPER LOW TO LIVE EAST-NORTHEAST WITH CONVECTION DEVELOPING
ALONG FRONT THIS EVENING IN FAR WESTERN ND AND THEN SOME CHANCE OF
A COMPLEX MOVING EAST INTO ERN ND OVERNIGHT. LATEST RAP SHOWS
QUITE IMPRESSIVE SHOWALTERS DOWN TO -10C 06Z-07Z INTO SE ND IN THE
LEFT QUAD OF A 40-45 KT LOW LEVEL JET OVER EASTERN SD. SO IN THAT
RESPECT MODELS MAYBE UNDERESTIMATING PRECIP TONIGHT.
AFTER COORD WITH WFO BIS....ONLY REAL CHANGE TO FCST IS TO REMOVE
THAT BLENDED POP ZONE IN DEVILS LAKE REGION WE HAD LATE THIS AFTN.
NOTHING THERE TIL PAST 00Z.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 315 AM CDT WED SEP 3 2014
CONVECTION CHANCES...SEVERITY...AND TIMING WILL BE THE HEADACHES
FOR THE SHORT TERM.
STRONG SHORTWAVE TROUGH CURRENTLY DIGGING INTO THE PAC NW WILL
QUICKLY MOVE INTO MT DURING THE DAY TODAY. SFC LOW PRESSURE OVER
MT/WY WILL MOVE INTO THE DAKTOAS BY THIS AFTERNOON. CONVECTION FIRING
ALONG THE NOSE OF THE LOW LEVEL JET OVER EASTERN SOUTH DAKOTA WILL
CONTINUE NORTHEASTWARD AND MAY CLIP PART OF GRANT COUNTY LATER
THIS MORNING. THUS...KEPT SOME LOW POPS GOING FOR THIS MORNING BUT
THINK THE BETTER PRECIP CHANCES WILL HOLD OFF UNTIL LATER THIS
AFTERNOON AS THE SFC LOW COMES EAST AND A WARM FRONT LIFTS INTO
OUR FAR SOUTHERN COUNTIES. MODELS BRING UP QUITE A LOT OF MOISTURE
WITH THE FRONT...WITH THE NAM SHOWING LOW 70S DEW POINTS IN OUR
FAR SOUTH BY AFTERNOON. HOWEVER...GIVEN THE CURRENT READINGS OVER
NEB THINK THAT THE ECMWF/GFS WITH DEW POINTS IN THE 60S WILL BE
MORE IN LINE WITH REALITY. WITH WINDS ALOFT INCREASING AHEAD OF
THE SHORTWAVE BULK SHEAR VALUES WILL BE PUSHING 50 KTS BY THIS
AFTERNOON. SEVERE WEATHER WILL BE A POSSIBILITY...PARTICULARLY IN
THE LOW LEVEL SHEAR AREA NEAR THE WARM FRONT.
TONIGHT...THE SHORTWAVE TROUGH WILL MOVE INTO WESTERN ND...WITH
THE SFC LOW ENTERING THE EASTERN DAKOTAS. THERE WILL BE SOME GOOD
FRONTOGENESIS IN NORTHEASTERN SD AND OUR FAR SOUTHERN COUNTIES AS
THE SFC LOW PUSHES EAST. GFS/NAM BREAK OUT PRECIP OVER THE
SISSETON HILLS REGION INTO OUR SOUTHERN COUNTIES BUT THE ECMWF AND
GEM ARE DRIER. WARM MID LEVEL TEMPS MAY KEEP A LID ON CONVECTION
BUT THINK THAT THERE IS ENOUGH CHANCE FOR STORMS ALONG THAT
SOUTHERN SFC LOW CENTER THAT CONTINUED TO KEEP SOME CHANCE POPS
GOING. FURTHER NORTH...THE MAIN SHORTWAVE WILL BE MOVING INTO
SOUTHERN CANADA AND THE MODELS SHOW SOME HEAVY QPF ALONG THE
DEFORMATION ZONE TO THE NORTHWEST OF A NORTHERN LOW CENTER
DEVELOPING ALONG THE CANADIAN BORDER. CONTINUED TO KEEP HIGH POPS
GOING FOR THE NORTH IN AREAS THAT WILL BE CLOSER TO THE MAIN
UPPER SHORTWAVE. CENTRAL COUNTIES WILL SEE LESSER CHANCES THAN THE
FAR NORTH AND FAR SOUTH...BUT KEPT SOME SLIGHT POPS.
THURSDAY...THE MAIN SHORTWAVE WILL MOVE OFF INTO SOUTHERN
CANADA...WITH THE SFC LOW MOVING INTO THE GREAT LAKES. THERE WILL
BE SOME GOOD ISENTROPIC DOWNGLIDE MOVING INTO OUR WESTERN COUNTIES
AND THEN ACROSS THE CWA FROM MID MORNING INTO THE AFTERNOON. THERE
COULD BE SOME WRAP AROUND PRECIP IN THE NORTH...BUT MODELS ARE
SHOWING A TREND OF A DRY SLOT COMING IN FOR MUCH OF THE CWA. WINDS
WILL BE A GREATER CONCERN WITH STRONG COLD AIR ADVECTION AND A
TIGHT PRESSURE GRADIENT. CONTINUED TO KEEP SPEEDS BELOW ADVISORY
CRITERIA FOR NOW BUT WILL MONITOR. THE NORTHWEST WINDS WILL BRING
IN SOME COOLER AIR AND OUR NORTHWESTERN COUNTIES COULD STAY IN THE
LOW 60S WHILE THE SOUTHEAST WILL BE WARMER WITH A LATER FRONTAL
PASSAGE.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 315 AM CDT WED SEP 3 2014
THURSDAY NIGHT THROUGH FRIDAY NIGHT...SOME LINGERING SHOWERS WILL
BE POSSIBLE THURSDAY NIGHT AS THE SFC LOW PULLS AWAY INTO THE
GREAT LAKES. TEMPS SHOULD BE FAIRLY CHILLY IN THE 40S AS CLOUDS
BEGIN TO CLEAR OUT AND HIGH PRESSURE BUILDS INTO THE PLAINS. WEST
TO SOUTHWESTERLY WINDS WILL BRING IN SOME SLIGHTLY WARMER AIR FOR
FRIDAY WHICH WILL HELP KEEP TEMPS IN THE UPPER 60S...BUT ANOTHER
REINFORCING SHORT WAVE WILL BE DIGGING INTO THE PLAINS FRIDAY AND
FRIDAY NIGHT AND BRING DOWN ANOTHER FRONTAL BOUNDARY. A FEW OF THE
MODELS BREAK OUT SOME PRECIP WITH THIS REINFORCING FRONT...BUT
THINK THAT THERE WILL NOT BE MUCH MOISTURE AVAILABLE SO KEPT THE
FORECAST DRY FOR NOW. TEMPS FRIDAY NIGHT WILL BE MODERATED BY
CLOUD COVER BUT WILL STILL BE MAINLY IN THE 40S THANKS TO COLD AIR
ADVECTION.
SATURDAY THROUGH TUESDAY...PERIOD STARTS WITH A NORTHWEST FLOW AND
ENDS WITH THE NEXT SIGNIFICANT UPPER WAVE. FOR THE FIRST HALF OF
THIS PERIOD...INTO SUNDAY... THE WEATHER SHOULD BE PRECIPITATION
FREE. TIMING OF PRECIPITATION BECOMES PROBLEMATIC MONDAY AND
TUESDAY...AS RAW MODEL QPF IS PRETTY SCANT INTO 12Z MONDAY.
HOWEVER...WITH INCREASING SOUTHWEST FLOW ALOFT AND LOW - MID LEVEL
WAA AND INCREASINGLY COUPLED 200 MB JET STRUCTURE ARGUES FOR BROAD
LIFT. WITH THE GUIDANCE SUGGESTING ANOMALOUSLY HIGH...FOR
SEPTEMBER...TD AND PWATS APPROACHING +2 SIGMA CANNOT ARGUE AGAINST
BLENDED POPS. OVERALL TEMPERATURES AS FORECAST ARE PRETTY CLOSE TO
EARLY SEPTEMBER MEDIAN VALUES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 641 AM CDT WED SEP 3 2014
PATCHY FOG HAS IMPACTED KTVF AND KGFK AT TIMES THIS
MORNING...GOING RAPIDLY UP AND DOWN IN VIS. INCLUDED TEMPO GROUP
AT KGFK TO ACCOUNT FOR PATCHY FOG BUT THINK THAT ALL SITES WILL
SEE FOG DISSIPATE BY 13 OR 14Z. VFR CONDITIONS WILL CONTINUE FOR
MUCH OF THE PERIOD WITH EAST WINDS AROUND 10 KTS. WARM FRONT
MOVING IN FROM THE SOUTH MAY BRING SOME STORMS NEAR THE KFAR
AREA...AND THERE WILL BE ANOTHER ROUND OF STORMS POSSIBLE AFTER
06Z IN THE NORTHERN TAF SITES. JUST INCLUDED VCTS MENTION AT
KFAR...KDVL...AND KGFK FOR NOW. THERE COULD BE SOME MVFR CIGS LATE
IN THE PERIOD WITH MORE MOISTURE IN THE REGION...BUT JUST INCLUDED
THE LOWER CIGS AT KDVL AND KBJI FOR NOW.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...JR
LONG TERM...JR/EWENS
AVIATION...JR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
618 AM CDT WED SEP 3 2014
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 338 AM CDT WED SEP 3 2014
MAIN CONCERN FOCUSED ON SEVERE POTENTIAL TONIGHT AND AGAIN THURSDAY
NIGHT.
WATER VAPOR OR BIG PICTURE VIEW SHOWS A FAIRLY HIGH ZONAL FLOW
ACROSS THE NORTHERN CONUS. A WEAK EMBEDDED MID-LEVEL TROUGH WAS
NOTED EJECTING NORTHEAST OUT OF WY INTO WESTERN SD. AT THE
SURFACE...A WARM FRONT EXTENDED FROM SOUTHWEST SD INTO EASTERN NEB.
LIFT AHEAD OF THE WAVE AND WARM FRONT WAS PRODUCING A SMALL AREA OF
SHOWERS/THUNDERSTORMS OVER EASTERN SD/FAR SOUTHWEST MN PER LATEST
REGIONAL RADAR MOSAIC. OTHERWISE...CLOSER TO HOME...HIGH PRESSURE WAS
PRODUCING MOSTLY CLEAR SKIES ACROSS THE FORECAST AREA WITH
TEMPERATURES RANGING FROM THE LOWER 50S A NEAR 60 DEGREES.
FOR TODAY...SURFACE CYCLOGENESIS WILL CONTINUE TO TAKE SHAPE OVER
MT/NORTHERN PLAINS. THIS WILL LIFT THE AFOREMENTIONED WARM FRONT OUT
OF THE CENTRAL PLAINS INTO SOUTHERN MN. ALSO...STRENGTHENING
SOUTHERLY FLOW WILL PRODUCE INCREASING MOISTURE TRANSPORT/ISENTROPIC
LIFT INTO THE AREA. THIS IS EXPECTED TO FUEL ELEVATED AND SCATTERED
SHOWERS/THUNDERSTORMS MAINLY ALONG AND NORTH OF I-90 THROUGH THE
DAY. PLAN ON HIGHS IN THE 75-85 DEGREE RANGE.
AS WE GO INTO TONIGHT...STRENGTHENING LOW PRESSURE MOVING FROM THE
DAKOTAS INTO WESTERN MN WILL DRIVE THE WARM FRONT FARTHER
NORTHEAST...NEAR THE I-94 CORRIDOR BY MORNING. THIS IS WHERE IT GETS
COMPLICATED. 850MB MOISTURE TRANSPORTS CRANKS UP SIGNIFICANTLY WITH
VECTORS POINTED DIRECTLY INTO THE AREA. AT THE SAME TIME...STRONG
CAP SETS UP ALONG THE MISSISSIPPI RIVER AS EVIDENCED BY THE NAM/GFS
BUFKIT SOUNDINGS. EXPECTING A COMPLEX OF THUNDERSTORMS TO FIRE
SOMEWHERE ALONG I-94 BETWEEN THE TWIN CITIES AND SAINT CLOUD MN BY
THIS EVENING ON THE EDGE OF THIS CAP AND ON THE NOSE OF THE MOISTURE
TRANSPORT. FORWARD PROPAGATING CORFIDI VECTORS BRING THIS COMPLEX
SOUTHEAST AND THEN ON A MORE SOUTHERLY TRAJECTORY ONCE IT GETS EAST
OF THE MISSISSIPPI...AGAIN ON THE EDGE OF THE CAP AND IN THE
CORRIDOR OF VERY RICH MOISTURE FEED.
THIS COMPLEX WILL HAVE TO BE WATCHED CLOSELY FOR SEVERE THREAT.
EARLY ON IN THE EVENING...MODEL CONSENSUS 0-3KM MUCAPE OF 2500-
4000J/KG AND 0-6KM BULK SHEAR OF 40-50KT WILL BE SUFFICIENT FOR
SUPERCELL DEVELOPMENT MAINLY ACROSS EAST CENTRAL MN INTO NORTHWEST
WI FOR LARGE HAIL POTENTIAL...AND TORNADO THREAT IF STORMS GET
ROOTED IN THE BOUNDARY LAYER. AS MENTIONED...THEN EXPECTING THIS
THUNDERSTORM COMPLEX TO FOLLOW CORFIDI VECTORS...TAKING INTO DIRECTLY
OVER OUR AREA MAINLY EAST OF THE MISSISSIPPI RIVER TONIGHT. BY THEN
MOST OF THESE STORMS WILL BE ELEVATED IN NATURE. WITH PRECIPITABLE
WATER VALUES OF 1.5-2 INCHES OFF THE NAM AND GFS...HEAVY RAINFALL
BECOMES THE MAIN THREAT ALONG WITH DAMAGING WIND POTENTIAL. SOME
LARGE HAIL WILL ALSO BE POSSIBLE. CANNOT RULE OUT THE POSSIBILITY OF
SOME FLASH FLOODING IF THERE IS ANY REPETITIVE CONVECTION OVER NAY
ONE AREA...BUT SYSTEM SEEMS OVERALL PRETTY PROGRESSIVE IN NATURE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 338 AM CDT WED SEP 3 2014
MODELS SHOW DEEP AREA OF LOW PRESSURE MOVING NORTH OUT OF WESTERN MN
INTO WESTERN ONTARIO BY LATE AFTERNOON. AS A RESULT...WARM FRONT WILL
PUSH NORTHEAST THROUGH THE AREA WITH A VERY WARM/HUMID/CAPPED DAY IN
STORE. HIGH TEMPERATURES ARE EXPECTED TO PUSH INTO THE 85-91 DEGREE
RANGE WITH DEW POINTS IN THE LOWER 70S. THIS WILL RESULT IN HEAT
INDICES OF 90-100.
AS THE LOW CONTINUES TO LIFT NORTHEAST INTO ONTARIO A COLD FRONT
WILL THEN PUSH THROUGH THE AREA THURSDAY NIGHT. INITIALLY THE AREA
REMAINS UNDER THE INFLUENCE OF THE STRONG CAP...BUT CONVECTION IS
EXPECTED TO EVENTUALLY FIRE IN THE EVENING AFTER 6 PM...AS THE
FRONT/ALONG WITH MID-LEVEL TROUGH MOVES IN WITH COOLING
ALOFT...WHICH SHOULD THEN BE ENOUGH TO OVERCOME THE CAP. SOME OF
THESE STORMS SHOULD BE COME SEVERE WITH DAMAGING WIND AND LARGE HAIL
BEING THE MAIN THREATS.
FOR FRIDAY INTO THE WEEKEND...
DRIER/COOLER AIR MOVES INTO THE AREA FRIDAY BEHIND THE FRONT. LOOK
FOR HIGHS IN THE UPPER 60S TO THE MIDDLE 70S.
COOL AND DRY CONDITIONS LOOK TO PERSIST THROUGH THE WEEKEND AS
CANADIAN HIGH PRESSURE DOMINATES THE MID-SECTION OF THE CONUS/UPPER
MISSISSIPPI RIVER VALLEY REGIONS. HIGHS SATURDAY AND SUNDAY STAY IN
THE UPPER 60S/LOWER 70S WITH OVERNIGHT LOWS DIPPING INTO THE 40S AND
LOWER 50S.
FOR MONDAY INTO TUESDAY...
HIGH PRESSURE DRIFTS OFF TO THE EAST AS LOW PRESSURE APPROACHES FROM
THE PLAINS. AS A RESULT...PLAN ON SHOWER/THUNDERSTORM CHANCES TO
INCREASE THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 617 AM CDT WED SEP 3 2014
AREA OF ELEVATED SHOWERS AND STORMS OVER SOUTHWEST MINNESOTA IN
ASSOCIATION WITH A WEAK SHORT WAVE TROUGH. THE 03.09Z RAP SUGGESTS
THE WAVE WILL CONTINUE TO MOVE EAST TOWARD THE AREA WHILE THE MID
LEVEL MOISTURE TRANSPORT LIFTS NORTHEAST. THE 03.00Z HI-RES ARW
AND 03.09Z HRRR BOTH SUGGEST THE ACTIVITY WILL LIFT NORTHEAST WITH
THE MOISTURE TRANSPORT AND MISS BOTH TAF SITES. FEEL THE BULK OF
THE ACTIVITY SHOULD MISS THE TAF SITES BUT WILL CARRY A VCTS AT
KRST IN THE EVENT THAT THE MOVEMENT ENDS UP BEING MORE TO THE
EAST. AFTER THAT...WARM AIR ALOFT WILL RAPIDLY BUILD OVER THE AREA
TODAY PUTTING A CAP IN PLACE THAT SHOULD ALLOW THE NEXT ROUND OF
CONVECTION TO FORM NORTH OF BOTH TAF SITES LATE THIS AFTERNOON
INTO THE EVENING. ALL THE MESO MODELS SUGGEST THE ACTIVITY WILL
THEN STAY NORTH OF THE AREA THROUGH THE OVERNIGHT...BUT THE 03.00Z
ECMWF SUGGEST SOME SOUTHEAST MOVEMENT ALONG THE EDGE OF THE CAP
CLOSE TO THE BACKWARD PROPAGATING CORFIDI VECTORS. IF THIS CAN
OCCUR...THERE IS A CHANCE SOME ACTIVITY COULD MOVE DOWN THE
MISSISSIPPI RIVER INTO WESTERN WISCONSIN AND WILL CONTINUE TO
CARRY A VCTS IN THE LATE EVENING FOR THIS AT KLSE BUT THINK IT
WILL MISS KRST...IF IT CAN TURN SOUTHEAST. WITH THE STRONG LOW
LEVEL JET FEEDING INTO THE CONVECTIVE ACTIVITY...LOW LEVEL WIND
SHEAR SHOULD BE PRESENT AND HAVE INCLUDED THIS OUTSIDE OF THE
THUNDER TIME IN THE EVENING AND OVERNIGHT HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
350 PM EDT WED SEP 3 2014
.DISCUSSION...
CURRENT/TONIGHT...
LATEST RUC SHOWS THE AXIS OF THE ERLY WAVE HAS MOVED LITTLE SINCE
DAYBREAK WITH THE H85-H50 AXIS AS WELL AS ITS H100-H70 REFLECTION
STILL LURKING JUST OFF THE E FL COAST AS OF MID AFTN. RADAR SHOWING
SCT SHRAS OVER THE INTERIOR THAT WILL PUSH W OF THE CWA WELL BEFORE
SUNSET. UPSTREAM...A SECOND BAND OF SHRAS/TSTMS OVER THE ATLC WILL
PROVIDE NEXT ROUND OF PRECIP FOR EAST CENT FL.
WHILE MID LVL ENERGY IS PRESENT IN THE FORM OF A BAND OF DEEP LYR
VORT BTWN THE NRN BAHAMAS AND THE E FL COAST...THE BULK OF THE
ENERGY REMAINS WELL S AND E OF LAKE OKEECHOBEE. RUC ANALYSIS
INDICATES MID LVL LAPSE RATES HAVE CHANGED LITTLE SINCE THE MRNG
RAOBS WITH H85-H50 READINGS HOLDING ARND 5.5C-KM. UPSTREAM MOISTURE
REMAINS PLENTIFUL WITH H100-H70 MEAN RH VALUES AOA 80PCT...H85-H50
VALUES AOA 60PC...BUT A REFLECTION OF THE DRY TONGUE LINGERS OVER
THE SPACE COAST WITH H85-H50 RH DECREASING TO AOB 40PCT.
CHC SHRAS ALONG THE COAST OVERNIGHT AND OKEECHOBEE COUNTY
OVERNIGHT...INCREASING N TO S TO REFLECT THE CURRENT MOISTURE
PROFILE. WILL KEEP SLGT CHC SHRAS IN FOR THE INTERIOR N OF
OKEECHOBEE COUNTY THRU 02Z TO ACCOUNT FOR ONGOING PRECIP...BUT GIVEN
THE LACK OF EITHER DYNAMIC OR THERMODYNAMIC INSTABILITY...THESE
SHOULD COLLAPSE ONCE THE LOSS OF DIURNAL HEATING KICKS IN. MIN TEMPS
IN THE L/M70S.
THU-FRI...
THE ERLY WAVE WILL ROTATE AROUND THE WRN FLANK OF THE ATLC RIDGE AND
ALLOW DEEP MOISTURE TO INCREASE ACRS CENTRAL FL WITH PWATS
RECOVERING TO ARND 1.8" ON THU...AND BTWN 2.0"-2.2" ON FRI. WITH THE
CWA GAINING THE ASCENDING SIDE OF THE WAVE...NUMEROUS SHRA AND SCT
TSRAS SHOULD FORM EACH DAY. LCL HEAVY RAIN MAY OCCUR WITH STRONGER
THAT DVLP IN THE AFTERNOON AS H50 TEMPS COOL TO ARND -8C. PRECIP
CHANCES SLIGHTLY LOW ON FRI AS THE WAVE BEGINS TO PUSH INTO THE
GOMEX WITH THE ATLC RIDGE REBUILDING IN ITS WAKE.
DESPITE INCREASING CLOUD COVER...SE LOW LVL WINDS WILL GENERATE AFTN
MAX TEMPS TO PUSH MAX TEMPS INTO THE U80S/L90S AREAWIDE. ONSHORE
FLOW AND SFC DEWPOINTS IN THE L/M70S WILL KEEP MIN TEMPS A FEW DEGS
ABV AVG...GENERALLY IN THE M/U70S.
EXTENDED...(PREV DISC)
SAT-SUN...THE ATLANTIC RIDGE WILL EXTEND WEST ACROSS CENTRAL FL OVER
THE WEEKEND WITH A RETURN A MORE TYPICAL SEA BREEZE REGIME WITH LESS
INFLUENCE FROM UPPER LEVEL FEATURES AS THE MID LVL RIDGE REBUILDS
OVER THE STATE. THE EAST COAST SEA BREEZE SHOULD MOVE INLAND EACH
AFTERNOON WITH THE HIGHEST SHOWER/THUNDERSTORM COVERAGE WEST OF I-95
INTO THE INTERIOR BY THE MID TO LATE AFTERNOON HOURS. RAIN CHANCES
AROUND 30 CLOSE TO THE COAST AND 40-50 PERCENT FOR THE INTERIOR.
HIGHS AROUND 90 COAST TO AROUND 93 FOR THE INTERIOR ZONES.
MON-WED...APPEARS THE MID LVL RIDGE WILL REMAIN IN CONTROL EARLY
NEXT WEEK WITH LOW LVL SE WINDS FORECAST. THIS SHOULD AGAIN FAVOR
THE INTERIOR FOR AFTERNOON STORMS WITH THE INLAND MOVING DIFFUSE
EAST COAST BREEZE. MOISTURE LEVELS LOOK TO DIMINISH SOME SO WILL
FORECAST RAIN CHANCES 30 PCT COASTAL TO 40 PCT FOR THE INTERIOR. NOT
MUCH DAY TO DAY CHANGE IN HIGH TEMPS EXPECTED WITH AROUND 90 COAST
TO THE LOWER 90S INLAND.
&&
.AVIATION...
THRU 04/00Z...E/SE SFC WND 8-12KTS...SW OF KDED-KVRB SCT MVFR
SHRAS/ISOLD IFR TSRAS WITH PSBL SFC WND G25-30KTS...NE OF KDED-KVRB
ISOLD MVFR SHRAS. BTWN 04/00-04/12Z...SE SFC WNDS AOB 5KTS...CHC
MVFR SHRAS E OF KOMN-KOBE. AFT 04/12Z...E/SE SFC WNDS 5-10KTS...
PREVAILING CIGS BTWN FL100-120...CHC MVFR SHRAS ALL SITES.
&&
.MARINE...
TONIGHT...LIGHT TO GENTLE ERLY BREEZE BCMG SE AS THE AXIS OF AN ERLY
WAVE PUSHES ACRS THE LCL ATLC...SEAS AOB 2FT NEARSHORE AND 2-3FT
OFFSHORE WITH DOMINANT PDS AOA 8SEC. SCT SHRAS AND ISOLD TSRAS...
MORE NUMEROUS GULF STREAM AND NEARSHORE WATERS S OF SEBASTIAN INLET.
THU-FRI...GENTLE TO MODERATE SERLY BREEZE WILL PREVAIL AS THE ERLY
WAVE ROTATES AROUND THE WRN FLANK OF THE ATLC RIDGE. SEAS AOB 2FT
NEARSHORE AND 2-3FT OFFSHORE...DOMINANT PDS ARND 8SEC THU...
DECREASING TO 7SEC N OF ST. LUCIE INLET AND 4-5SEC S OF THE INLET AS
THE SE BREEZE PLACES THE LCL ATLC UNDER THE SHADOW OF GRAND BAHAMA
ISLAND. NMRS SHRAS AND SCT TSTMS THU...BCMG SCT/ISOLD ON FRI AS THE
WAVE LIFTS INTO THE GOMEX.
SAT-SUN...
SFC/BNDRY LYR WINDS WILL SHIFT MORE TO THE S ARND 10KTS AS THE ATLC
RIDGE REBUILDS OVER THE FL STRAITS IN THE WAKE OF THE DEPARTING
WAVE. SEAS 2-3FT AREAWIDE. SHRA/TSTM CHANCES DECREASING AS SLIGHTLY
DRIER AND MORE STABLE AIR PUSHES INTO THE LCL ATLC.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 74 89 75 88 / 30 50 30 40
MCO 74 93 75 92 / 20 50 20 40
MLB 75 90 77 89 / 40 60 30 40
VRB 72 90 76 89 / 50 60 30 30
LEE 74 93 76 91 / 20 50 20 40
SFB 75 93 76 92 / 20 50 20 40
ORL 75 93 76 92 / 20 50 20 40
FPR 74 89 75 88 / 50 60 30 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECAST/AVIATION...BRAGAW
RADAR/IMPACT WX.....CRISTALDI
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
625 PM EDT WED SEP 3 2014
.SYNOPSIS...
HIGH PRESSURE WILL PREVAIL INTO THIS WEEKEND. A COLD FRONT WILL
STALL AND DISSIPATE NORTH OF THE REGION BY LATE WEEK...THEN A
STRONGER COLD FRONT COULD ADVANCE INTO THE REGION LATE IN THE
WEEKEND OR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WATER VAPOR IMAGERY AND RAP VORTICITY DATA SUGGEST THE AREA IS
UNDER THE INFLUENCE OF BROAD DIFFERENTIAL NEGATIVE VORTICITY
ADVECTION. THIS HAS RESULT IN A GENERAL LACK OF CONVECTIVE
ACTIVITY THIS AFTERNOON...DESPITE ADEQUATE INSTABILITY. THERE IS
STILL A RISK OF AN ISOLATED SHOWER OR TSTMS ACROSS FAR INTERIOR
SOUTHEAST GEORGIA AHEAD OF THE SEA BREEZE...BUT ANY ACTIVITY THAT
FIRES WILL BE SHORT LIVED. ADJUSTED POPS TO 20 PERCENT IN THIS
AREA WITH DRY CONDITIONS ELSEWHERE THROUGH THE EVENING HOURS.
LATER TONIGHT...ISOLATED SHOWERS/TSTMS COULD MOVE ONSHORE IN THE
ONSHORE FLOW/COASTAL CONVERGENCE REGIME. THE LATEST RUNS OF THE
RAP AND H3R SUPPORT THIS SCENARIO. MAINTAINED SLIGHT CHANCE POPS
OVER THE COASTAL WATERS AND BEACHES. LOWS WILL RANGE FROM THE
LOWER-MID 70S INLAND TO THE MID-UPPER 70S AT THE COAST AND
DOWNTOWN CHARLESTON.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
A MODERATELY STRONG...DEEP LAYER RIDGE OF HIGH PRESSURE WILL REMAIN
ANCHORED ACROSS THE ATLANTIC AND SOUTHEAST STATES THROUGH AT LEAST
FRIDAY. BY SATURDAY...THE WESTERN PORTION OF THE RIDGE BEGINS TO
ERODE/BREAK DOWN AS A BROAD UPPER TROUGH BUILDS INTO THE GREAT
LAKES STATES AND NORTHEAST U.S.. THIS UPPER TROUGH WILL ALSO PUSH A
WEAK COLD FRONT TO JUST NORTHWEST OF THE REGION BY LATE SATURDAY.
THURSDAY...MODELS HAVE BEEN CONSISTENTLY SHOWING A NARROW BAND OF
MID AND UPPER LEVEL DRYING TO MOVE INTO THE AREA FOR THE FIRST PART
OF THE DAY AROUND THE NW FRINGE OF THE UPPER/TUTT LOW...CURRENTLY
STRETCHING FROM THE BAHAMAS...SOUTHWEST INTO CUBA. THIS DRIER AIR
WILL HELP TO LIMIT CONVECTIVE COVERAGE. THUS...HAVE KEPT SLIGHT
CHANCE POPS MOST AREAS...EXCEPT LOW END CHANCE EXTREME INTERIOR
WHERE MAX HEATING COMBINES WITH A LATE DAY SEA BREEZE. MAX TEMPS
STILL IN THE LOWER 90S MOST AREAS...AND COMBINED WITH MODERATE LOW
LEVEL HUMIDITY... WILL RESULT IN MAX HEAT INDICES OF 100-103. ANY
CONVECTION SHOULD DIE DOWN AFTER SUNSET...THEN PARTLY CLOUDY WITH
LOWS IN THE 70S.
FRIDAY...BETTER DEEP LAYER MOISTURE ADVANCES BACK IN FROM THE
SOUTHEAST ON THE NW EDGE OF THE UPPER/TUTT LOW WELL TO THE SOUTH IN
THE GULF OF MEXICO. EXPECT SCATTERED MAINLY AFTERNOON AND EARLY
EVENING SHOWERS/THUNDERSTORMS...WITH BEST COVERAGE LIKELY INLAND.
HIGHS AROUND 90 TO THE LOWER 90S. GUIDANCE TRIES TO HOLD ONTO POPS
ALL NIGHT FRIDAY NIGHT...BUT STILL FEEL CONVECTION WILL BE MAINLY
DIURNALLY FORCED. TO LEAN MORE TOWARD GUIDANCE AND TO BETTER
COLLABORATE WITH SURROUNDING OFFICES...HAVE KEPT SLIGHT CHANCE OVER
LAND AND CHANCE OVER WATER/ATLANTIC REGION. LOWS AGAIN IN THE 70S.
SATURDAY...DEEP LAYER MOISTURE REMAINS HIGH WITH PRECIPITABLE WATER
VALUES OVER 2 INCHES. NAM SHOWING A WEAK SURFACE LOW MOVING UP THE
COAST FROM FL TO OFF SC COAST. OTHER MODELS MAINLY SHOW A WEAK
INVERTED SURFACE TROUGH. THE DETAILS OF THE SURFACE FEATURES ARE
STILL UNCERTAIN. HOWEVER...GIVEN SLIGHTLY LOWER UPPER HEIGHTS AND
SUFFICIENT TROPICAL MOISTURE...EXPECT AT LEAST SCATTERED
CONVECTION...AND WOULD NOT BE SURPRISED IF POPS NEED TO BE RAISED
MORE WITH LATER FORECASTS. HIGH TEMPERATURES AROUND 90 TO THE LOWER
90S...BUT MAY BE LOWER IF CONVECTIVE COVERAGE ENDS UP BEING HIGHER
THAN CURRENTLY FORECASTED.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A SHIFT IN THE PATTERN WILL BRING ABOUT IMPROVING RAIN CHANCES INTO
THE EARLY PART OF NEXT WEEK WITH COOLER TEMPERATURES RESULTING.
HEIGHTS WILL FALL ALOFT AS THE AFOREMENTIONED NORTHERN STREAM TROUGH
MOVES PAST. THIS WILL DRAG A COLD FRONT INTO THE AREA SOMETIME
SUNDAY...LINGERING IN THE VICINITY THROUGH MONDAY BEFORE DISSIPATING
THEREAFTER. PWATS WILL INCREASE TO OVER 2 INCHES AND THE CONVERGENCE
WITHIN THE BOUNDARY IS EXPECTED TO RESULT IN MUCH BETTER COVERAGE OF
SHOWERS AND THUNDERSTORMS SUNDAY...SUNDAY NIGHT...AND INTO MONDAY.
POPS HAVE BEEN INCREASED INTO THE 50 PERCENT RANGE. BY THE LATTER
PORTION OF THE FORECAST...CONFIDENCE IS A BIT LOWER AS THE MODELS
SHOW HIGH PRESSURE TO THE NORTHEAST BUILDING IN WITH THE REMNANT
BOUNDARY SOMEWHERE ALONG THE COAST OR JUST OFFSHORE. IN SHORT...THE
LONG TERM PERIOD FEATURES INCREASING RAIN CHANCES AND COOLER
TEMPERATURES.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
VFR.
EXTENDED AVIATION OUTLOOK...VFR EXPECTED TO PREVAIL THROUGH
FRIDAY. ONLY ISOLATED TO SCATTERED AFTERNOON SHOWERS/THUNDERSTORMS
EXPECTED BOTH TERMINALS WITH BRIEF PERIODS OF FLIGHT RESTRICTIONS
POSSIBLE. RAIN CHANCES MAY INCREASE SATURDAY AND SUNDAY AS EVEN
DEEP TROPICAL MOISTURE TRIES TO MOVE FROM THE SOUTH INTO THE
REGION...AND INTERACTS WITH AN APPROACHING COLD FRONT LATE WEEKEND
AND EARLY NEXT WEEK.
&&
.MARINE...
TONIGHT THROUGH SUNDAY...HIGH PRESSURE WILL CONTINUE TO BE THE PRIMARY
FEATURE THROUGH THE END OF THE PERIOD. A COLD FRONT WILL BEGIN TO
APPROACH THE LOCAL WATERS LATE IN THE WEEKEND...BUT WILL NOT HAVE
A SIGNIFICANT EFFECT ON WINDS/SEAS. THE PREVAILING FLOW WILL
CONTINUE TO BE SOUTH TO SOUTHEASTERLY WITH SPEEDS LESS THAN 15 KT.
PERIODS OF STRONGER FLOW WILL BE POSSIBLE ALONG THE LAND/SEA
INTERFACE WITH THE SEA BREEZE...AS WELL IN MODEST NOCTURNAL
SURGING. SEAS WILL CONTINUE TO BE 1-3 FT...HIGHEST BEYOND 20 NM.
&&
.TIDES/COASTAL FLOODING...
ASTRONOMICAL TIDE HEIGHTS WILL GRADUALLY INCREASE THROUGH THE WEEK
AS WE APPROACH A PERIGEAN FULL MOON NEXT WEEK AND EARLY NEXT WEEK.
EXTRA-TROPICAL STORM SURGE MODEL RUNS HAVE BEEN TRENDING TOWARD
INCREASING TIDE LEVELS THROUGH THE WEEK...WITH THE LATEST RUN NOW
PREDICTING TIDES JUST ABOVE 7 FT MLLW FOR CHARLESTON /MARGINAL
COASTAL FLOODING/...BUT REMAIN JUST BELOW 9 FT FOR FT. PULASKI.
GIVEN THIS LATEST FORECAST...LOOKS LIKE THE BEST THREAT FOR MINOR
COASTAL FLOODING WOULD BE THE CHARLESTON/SC COAST BY SATURDAY. IF
THE ONSHORE FLOW IS STRONGER THAN CURRENTLY PREDICTED...MINOR
COASTAL FLOODING COULD BEGIN AS EARLY AS FRIDAY EVENING.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS TOPEKA KS
348 PM CDT Wed Sep 3 2014
.SHORT TERM...(This Evening through Thursday)
Issued at 345 PM CDT WED SEP 3 2014
Water vapor loop shows relatively zonal flow across the Central
Plains with weak disturbances moving through. One vort max appears
to be along the border between northwest KS and southwest NE and
seems to be associated with thunderstorm cluster moving into eastern
Nebraska. HRRR has been the only model that developed convection
into central KS this evening, and has done so for the last several
runs. RAP just recently has forecast precip into same general area
in the next several hours. Meanwhile, all other models are keeping
central and eastern KS dry tonight. Confidence is not high enough
that HRRR is right, and thus have continued with POPs below 20% for
tonight in forecast area.
Good pressure gradient across the area tonight will maintain
southerly winds of 10 to 15 kts most areas. This should help keep
minimum temperatures up in the lower to middle 70s.
On Thursday, more sunshine than today and warm temperature aloft
will allow highs to reach the mid 90s most areas. Combined with
dewpoints generally in the upper 60s to lower 70s, peak afternoon
heat indices should reach the 100 to 105 range. Frontal boundary
approaches northwest corner of our CWA around 21Z on Thursday, thus
the chance of late afternoon thunderstorms is continued in that
area.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 345 PM CDT WED SEP 3 2014
Models are in good agreement that the cold front will traverse the
county warning area Thursday night into midday Friday...although
the GFS is the fastest. Convection that develops along and front
Thursday night will have the greatest impact with coverage and
rainfall amounts across the northern 1/3 of the cwa through sunrise
Friday as the front advances southeastward. Will range pops from
likely in the northwest counties to only a slight chance in the
far southeast near Garnett...then keep higher end chance pops all
areas on Friday along and behind the frontal passage and the
approach of a shortwave trough from the central high plains. This
wave will move east of the cwa early Saturday with diminishing
chances for rain north to south as much drier air overspreads the
area. With the frontal passage/cold air advection/clouds and
precip in the area will see much cooler highs from the upper 60s
around Belleville to the middle 80s south of I 35.
This will set the stage for lows in the 50s most areas Friday night
and Saturday night. With the dry air in place and high pressure
center over the area...will keep the area dry late Saturday through
Sunday with highs in the 70s both days.
With the flow aloft slowly transitioning from northwest on Saturday
to a more unsettled west to southwest flow into next week. As it
does...the chances for more thunderstorms will increase and so
will the high temperatures ahead of the next front which is
expected by early Wednesday as a larger scale upper trough moves
into the plains.
Will introduce pops in the north central by Sunday night and then
across the remainder of the cwa Monday into Wednesday.
Highs will generally be in the 80s...cooling slightly into the upper
70s and lower 80s by Wednesday.
&&
.AVIATION...(For the 18Z TAFs through 18Z Thursday Afternoon)
Issued at 1221 PM CDT WED SEP 3 2014
CIGS rising and clouds are scattering out so VFR conditions
expected through the forecast period. Southerly winds should
increase and be gusty into early evening. Very small chance that
some thunderstorms could develop across central KS this evening
and move toward MHK overnight. But chances too low for TEMPO or
PROB30 in TAF.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GDP
LONG TERM...63
AVIATION...GDP
AREA FORECAST DISCUSSION
NWS GOODLAND KS
244 PM MDT WED SEP 3 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 150 PM MDT WED SEP 3 2014
WARM SOUTHWESTERLY MID LEVEL FLOW AND DEEP MIXING HAS RESULTED IN
SIGNIFICANTLY ABOVE NORMAL TEMPERATURES TODAY WELL INTO THE 90S AT
MOST LOCATIONS. SOME HIGH BASED CU HAS FORMED EARLY THIS AFTERNOON
MAINLY OVER EASTERN COLORADO AND A FEW ISOLATED SHOWERS/STORMS ARE
POSSIBLE LATE THIS AFTERNOON AND EVENING. THE BEST CHANCE WILL BE
THE FAR SOUTHERN PORTION OF THE FORECAST AREA WHERE RAP SOUNDINGS
SHOW DEEP MIXING BUT MORE BOUNDARY LAYER MOISTURE AND INSTABILITY
THAN FURTHER NORTH.
AN UPPER LEVEL SHORTWAVE IS EVIDENT ON WATER VAPOR IMAGERY
OVER THE NORTHERN ROCKIES MOVING EASTWARD. THIS SHORTWAVE WILL MOVE
INTO THE NORTHERN PLAINS TONIGHT FORCING SURFACE CYCLOGENESIS TO
OUR NORTH. TIGHTENING SURFACE PRESSURE GRADIENT WILL RESULT IN
INCREASING WINDS BACKING TO MORE OF A SOUTHERLY DIRECTION THIS
EVENING AND INTO THE NIGHT. SUFFICIENT MIXING AND LESS LOW LEVEL
MOISTURE THAN PREVIOUS NIGHTS SHOULD PRECLUDE A FOG THREAT
OVERNIGHT. A COLD FRONT WILL EVOLVE FROM LEE TROUGHING AND SURGE
SOUTHWARD ACROSS THE FORECAST AREA TOMORROW MORNING BRINGING COOLER
TEMPERATURES. WARM/MOIST ADVECTION OVER SURFACE BOUNDARY WILL RESULT
IN SHOWERS AND THUNDERSTORMS INCREASING BY LATE IN THE DAY TOMORROW
ACROSS THE SOUTHWESTERN PORTION OF THE AREA AND ESPECIALLY JUST
AFTER THE SHORT TERM PERIOD.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 242 PM MDT WED SEP 3 2014
THURSDAY NIGHT AND FRIDAY WIDESPREAD RAINFALL...HEAVY AT TIMES...LOOKS
VERY LIKELY FOR THE AREA.
THURSDAY NIGHT MID AND UPPER LEVEL MIXING RATIOS INCREASE AHEAD OF A
COMPACT UPPER LEVEL SHORT WAVE TROUGH THAT WILL MOVE ACROSS THE AREA
THROUGH THE NIGHT. AHEAD OF THE TROUGH ELEVATED CAPE DEVELOPS AS
THE JET AT 750MB NOSES IN THE FROM THE SOUTHEAST...AND PROGRESSES
NORTHWEST ACROSS MOST OF THE AREA THROUGH THE NIGHT. WITH
ISENTROPIC AS WELL AS SYNOPTIC LIFT OCCURRING ALONG THE NOSE OF THIS
JET...ANTICIPATE ELEVATED STORMS TO DEVELOP ALONG IT BY EARLY
EVENING. ELEVATED CAPE ABOVE 750MB MAY BE AS HIGH AS 2500J/KG ALONG
AND SOUTHEAST OF THE NOSE OF THE 750MB JET...WITH INSTABILITY
DECREASING DRAMATICALLY NORTHWEST OF THE NOSE. IF STORMS ARE ABLE
TO TAP INTO THE HIGHER INSTABILITY HAIL UP TO 2 INCHES IN DIAMETER
WILL BE POSSIBLE DUE TO DEEP LAYER SHEAR OF 35KTS. HOWEVER FURTHER
NORTHWEST OF THE JET NOSE HAIL SIZE WILL TAPPER OFF DRAMATICALLY DUE
TO LITTLE TO NO ELEVATED CAPE. PLACED SEVERE WORDING IN THE
FORECAST WHERE SEVERE STORMS WILL BE MOST LIKELY. IN ADDITION TO
THE LARGE HAIL...MEAN STORM MOTION WILL BE AROUND 20MPH AND WILL BE
PARALLEL TO THE NOSE OF THE 750MB JET. THIS WILL LEAD TO SLOW
MOVING TRAINING STORMS CAPABLE OF PRODUCING HEAVY RAINFALL.
ANTICIPATE STORMS TO START OFF AS MORE SUPER CELLULAR IN THE EVENING
WHEN ELEVATED CAPE IS HIGHEST. OVERNIGHT AS THE ELEVATED
INSTABILITY DIMINISHES AND ICE NUCLEI SEEDING FROM UPWIND STORMS
OCCURS...BELIEVE THE HAIL SIZE WILL BECOME SMALLER THAN ONE INCH IN
DIAMETER. HOWEVER HEAVY RAINFALL WILL BECOME MORE OF A THREAT.
FURTHER NORTHWEST OF THE NOSE OF THE 750MB JET 700-500MB THETA-E
LAPSE RATES INDICATE A CONVECTIVELY UNSTABLE ENVIRONMENT DESPITE THE
LACK OF ELEVATED CAPE. WITH UPPER LEVEL SHORT WAVE TROUGH MOVING
ACROSS MOST OF THE AREA THROUGH THE NIGHT DECIDED TO KEEP THE
RAINFALL CHANCES GOING FOR THE REST OF THE AREA...WITH THE BEST
CHANCE FOR RAINFALL ACTUALLY SHIFTING NORTH TOWARD THE NE BORDER
OVERNIGHT FOLLOWING THE HIGHER 700-500MB MIXING RATIOS AND 700-500MB
FRONTOGENESIS.
ASIDE FROM THE WIDESPREAD RAINFALL...A SECOND SURGE OF COOLER AIR
WILL MOVE INTO THE AREA FROM THE NORTH THROUGH THE NIGHT.
FRIDAY MORNING THE UPPER LEVEL SHORT WAVE TROUGH FROM LAST NIGHT
WILL EXIT THE AREA AS ANOTHER SHORT WAVE TROUGH DEEPENS OVER THE
WESTERN PART OF THE AREA. MEANWHILE THE BAND OF 700-500MB
FRONTOGENESIS STRENGTHENS THROUGH THE DAY AND MOVES EAST ACROSS THE
AREA AHEAD OF THIS SECOND SHORT WAVE TROUGH. CAPE WILL BE AROUND
1000J/KG OR LESS SO DO NOT ANTICIPATE A SEVERE THREAT SINCE THE CAPE
PROFILE WILL BE TALL AND NARROW WHICH FAVORS HEAVY RAINFALL. MEAN
STORM MOTION WILL CONTINUE TO BE AROUND 20MPH ALSO FAVORING HEAVY
RAINFALL. ANTICIPATE THE RAINFALL TO END FROM WEST TO EAST DURING
THE AFTERNOON AS THE UPPER LEVEL SHORT WAVE TROUGH EXITS THE AREA.
DUE TO THE COUPLE ROUNDS OF HEAVY RAINFALL POSSIBLE...A FLASH FLOOD
WATCH MAY BE NEEDED BUT WILL HOLD OFF FOR NOW IN ORDER TO GET A GOOD
HANDLE AS TO WHERE THE FLOODING THREAT WILL BE MOST LIKELY.
FRIDAY EVENING THERE MAY BE SOME LINGERING SHOWERS OVER THE EASTERN
PART OF THE AREA AS THE SHORT WAVE TROUGH MOVES EAST. DURING THE
LATE EVENING AND OVERNIGHT HOURS ANOTHER LESS COMPACT UPPER LEVEL
SHORT WAVE TROUGH WILL MOVE THROUGH THE AREA. CURRENTLY THE SOUTH
HALF TO 1/3 HAS THE BEST LIFT AND INSTABILITY SO WILL HAVE THE
HIGHER RAINFALL CHANCES THERE.
SATURDAY THROUGH WEDNESDAY NUMEROUS UPPER LEVEL SHORT WAVE TROUGHS
MOVE ACROSS THE AREA. TWO STRONGER SHORT WAVE TROUGHS WILL MOVE
THROUGH MONDAY AFTERNOON AND MONDAY NIGHT. AS A RESULT WILL HAVE
HIGHER RAINFALL CHANCES FOR MONDAY NIGHT. OTHERWISE LOW RAINFALL
CHANCES ARE FORECAST FOR VARIOUS PARTS OF THE AREA AS THE WEAKER
UPPER LEVEL DISTURBANCES MOVE THROUGH.
TEMPERATURES FOR THE PERIOD WILL START OFF COOLER THAN NORMAL THEN
GRADUALLY WARM TO NEAR NORMAL AS THE COOLER AIR MASS MOVES EAST OF
THE AREA. WEDNESDAY ANOTHER COLD FRONT WILL MOVE INTO THE AREA
BRINGING BELOW NORMAL TEMPERATURES WITH IT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1136 AM MDT WED SEP 3 2014
LOW STRATUS HAS DEPARTED THE AREA LEAVING CLEAR SKIES. VFR
CONDITIONS WILL PREVAIL THROUGH THE END OF THE TAF PERIOD. THE
SURFACE LEE SIDE TROUGH WILL STRENGTHEN THIS EVENING AND WINDS
SHOULD BACK SLIGHTLY TO A MORE SOUTHERLY DIRECTION AND INCREASE.
GUSTS OVER 20 KNOTS ARE POSSIBLE THIS EVENING AND MUCH OF THE
NIGHT...ESPECIALLY AT KGLD...BEFORE A PERIOD OF LIGHTER WINDS
TOMORROW MORNING. BY MID MORNING A COLD FRONT WILL PASS THROUGH
AND THE WINDS WILL SHIFT TO THE NORTH. GUSTS TO AROUND 25 KNOTS
ARE EXPECTED THROUGH LATE MORNING IMMEDIATELY BEHIND THE FRONT.
EXTENSIVE CLOUDS AND PRECIPITATION WILL HOLD OFF UNTIL WELL AFTER
THE END OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BRB
LONG TERM...JTL
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
150 PM MDT WED SEP 3 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 150 PM MDT WED SEP 3 2014
WARM SOUTHWESTERLY MID LEVEL FLOW AND DEEP MIXING HAS RESULTED IN
SIGNIFICANTLY ABOVE NORMAL TEMPERATURES TODAY WELL INTO THE 90S AT
MOST LOCATIONS. SOME HIGH BASED CU HAS FORMED EARLY THIS AFTERNOON
MAINLY OVER EASTERN COLORADO AND A FEW ISOLATED SHOWERS/STORMS ARE
POSSIBLE LATE THIS AFTERNOON AND EVENING. THE BEST CHANCE WILL BE
THE FAR SOUTHERN PORTION OF THE FORECAST AREA WHERE RAP SOUNDINGS
SHOW DEEP MIXING BUT MORE BOUNDARY LAYER MOISTURE AND INSTABILITY
THAN FURTHER NORTH.
AN UPPER LEVEL SHORTWAVE IS EVIDENT ON WATER VAPOR IMAGERY
OVER THE NORTHERN ROCKIES MOVING EASTWARD. THIS SHORTWAVE WILL MOVE
INTO THE NORTHERN PLAINS TONIGHT FORCING SURFACE CYCLOGENESIS TO
OUR NORTH. TIGHTENING SURFACE PRESSURE GRADIENT WILL RESULT IN
INCREASING WINDS BACKING TO MORE OF A SOUTHERLY DIRECTION THIS
EVENING AND INTO THE NIGHT. SUFFICIENT MIXING AND LESS LOW LEVEL
MOISTURE THAN PREVIOUS NIGHTS SHOULD PRECLUDE A FOG THREAT
OVERNIGHT. A COLD FRONT WILL EVOLVE FROM LEE TROUGHING AND SURGE
SOUTHWARD ACROSS THE FORECAST AREA TOMORROW MORNING BRINGING COOLER
TEMPERATURES. WARM/MOIST ADVECTION OVER SURFACE BOUNDARY WILL RESULT
IN SHOWERS AND THUNDERSTORMS INCREASING BY LATE IN THE DAY TOMORROW
ACROSS THE SOUTHWESTERN PORTION OF THE AREA AND ESPECIALLY JUST
AFTER THE SHORT TERM PERIOD.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 251 AM MDT WED SEP 3 2014
SEASONABLE PATTERN FOR THE FIRST WEEKEND OF SEPTEMBER WITH SOME LOW
CHANCES FOR PRECIP AND HIGHS RANGING FROM THE LOW 70S TO MID 80S.
ON THE SYNOPTIC SCALE AN UPPER RIDGE OVER WEST TEXAS/EAST NEW MEXICO
WILL GRADUALLY WEAKEN OVER THE WEEKEND. MODELS IN GENERALLY GOOD
AGREEMENT AT MID-LEVELS FOR A NORTHWEST TO ZONAL TO SOUTHWESTERLY
FLOW OVER THE WEEKEND...THOUGH SIGNIFICANT DIFFERENCES DEVELOP BY
LATE MONDAY ON THE TIMING OF MID-LEVEL SHORTWAVE TROUGHS. ECMWF
SEEMS TO PREFER A MORE ORGANIZED TROUGH AXIS MOVING THROUGH THE
CENTRAL HIGH PLAINS LATE MONDAY INTO EARLY TUESDAY...WHILE GFS
DEPICTS MORE NUMEROUS WEAK IMPULSES WHICH MAKE IT MORE DIFFICULT TO
FORECAST THE FINE-SCALE DETAILS.
AT THE SURFACE HIGH PRESSURE WILL DEVELOP ACROSS THE CENTRAL AND
NORTHERN PLAINS ON SATURDAY...DRIFTING EASTWARD INTO THE UPPER
MIDWEST ON SUNDAY. A NORTH-SOUTH ORIENTED SURFACE TROUGH WILL
DEVELOP NEAR THE KANSAS-COLORADO BORDER SUNDAY AND MONDAY RESULTING
IN BREEZY CONDITIONS AND OFFERING A FOCUS FOR STORMS TO DEVELOP EACH
DAY.
SATURDAY AND SUNDAY...REDUCED POPS SIGNIFICANTLY IN COLLABORATION
WITH NEIGHBORS AS IT APPEARS COLD FRONT WILL BE FARTHER SOUTH THAN
PREVIOUSLY THOUGHT. WITH NO LARGE-SCALE FORCING IN PLAY IT LOOKS
LIKE JUST A FEW DIURNALLY-DRIVEN SHOWERS/STORMS POSSIBLE ON SUNDAY
AFTERNOON. ALSO...AS SFC HIGH PRESSURE MOVES EAST SATURDAY INTO
SUNDAY THERE WILL BE LOW/MID LEVEL MOISTURE ADVECTION FROM THE
SOUTHWEST LEADING TO A CLOUDY DAY TO START MONDAY...LIMITING HEATING
AND THEREFOR FURTHER REDUCING THE LIKELIHOOD OF SHOWERS/STORMS ON
SUNDAY.
MONDAY/TUESDAY...BREEZY ON MONDAY WITH A SURFACE TROUGH DEVELOPING
AS PREVIOUSLY MENTIONED. ECMWF CLEARLY BRINGS A MID-LEVEL SHORTWAVE
TROUGH ACROSS THE REGION LATE MONDAY INTO TUESDAY WHILE THE
DETERMINISTIC GFS JUST DEPICTS A SERIES OF SUBTLE IMPULSES MOVING
FROMM EST TO EAST ACROSS THE ENTIRE GREAT PLAINS REGION. A NUMBER OF
GEFS MEMBERS DEPICT A PATTERN SIMILAR TO THE ECMWF DURING THIS
PERIOD...SO ULTIMATELY DECIDED TO KEEP THE TEENS TO 20S POPS. WITH
SOUTHERLY LOW-LEVEL FLOW THROUGH THE SUNDAY/MONDAY/TUESDAY TIMEFRAME
WILL SEE WARM AIR ADVECTION LEADING TO A WARMING TREND IN
TEMPS...WITH HIGHS REACHING THE LOW TO MID 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1136 AM MDT WED SEP 3 2014
LOW STRATUS HAS DEPARTED THE AREA LEAVING CLEAR SKIES. VFR
CONDITIONS WILL PREVAIL THROUGH THE END OF THE TAF PERIOD. THE
SURFACE LEE SIDE TROUGH WILL STRENGTHEN THIS EVENING AND WINDS
SHOULD BACK SLIGHTLY TO A MORE SOUTHERLY DIRECTION AND INCREASE.
GUSTS OVER 20 KNOTS ARE POSSIBLE THIS EVENING AND MUCH OF THE
NIGHT...ESPECIALLY AT KGLD...BEFORE A PERIOD OF LIGHTER WINDS
TOMORROW MORNING. BY MID MORNING A COLD FRONT WILL PASS THROUGH
AND THE WINDS WILL SHIFT TO THE NORTH. GUSTS TO AROUND 25 KNOTS
ARE EXPECTED THROUGH LATE MORNING IMMEDIATELY BEHIND THE FRONT.
EXTENSIVE CLOUDS AND PRECIPITATION WILL HOLD OFF UNTIL WELL AFTER
THE END OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BRB
LONG TERM...JJM
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS DULUTH MN
1253 PM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 1251 PM CDT WED SEP 3 2014
UPDATED FOR ONGOING THUNDERSTORMS IN THE ARROWHEAD. THESE STORMS
DEVELOPED ALONG A LINE OF ACCAS IN THE AREA.
UPDATE ISSUED AT 1229 PM CDT WED SEP 3 2014
UPDATED FOR AVIATION DISCUSSION BELOW.
UPDATE ISSUED AT 1110 AM CDT WED SEP 3 2014
UPDATED TO ADD HIGHER POPS TO SOUTHERN COUNTIES OF FCST AREA WITH
PRECIP SLOWLY DRIFTING NORTH.
UPDATE ISSUED AT 950 AM CDT WED SEP 3 2014
UPDATED TO ADJUST POPS ALONG THE SOUTHERN BORDER OF THE FCST AREA
BASED ON NORTHERN EXTENT OF THE PRECIP AREA IN SOUTHERN MN. THERE
IS SOME BACK BUILDING OF THE AREA IN THE SOUTH SO THE QUESTION IS
HOW MUCH WILL THE AREA AFFECT NE MN AND MW WI. IF THERE IS A LONG
ENOUGH BREAK IN THE PRECIP...THIS COULD ALLOW HIGHER DEWPOINTS TO
MOVE UP INTO THE FORECAST AREA. THE SREF AND HRRR IS HINTING AT
SOME DEVELOPMENT ACROSS THE SOUTHERN COUNTIES OF THE FORECAST AREA
AND MOVING NORTH BUT NOT AS MUCH AS EARLIER MODELS THIS MORNING.
THE NEXT 2-4 HOURS WILL INDICATE HOW THE SOUTHERN PRCIP AREA IS
AFFECTING DEVELOPMENT IN THE NORTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT WED SEP 3 2014
THE FOCUS IS ON THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS
THIS AFTERNOON AND TONIGHT. AT THE TIME OF THIS WRITING...THE
STORM PREDICTION CENTER HAD A SLIGHT RISK OF SEVERE STORMS OVER
MOST OF THE FORECAST AREA TODAY...WITH EXCEPTION OF THE FAR NORTH.
THERE IS THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...HEAVY
RAINFALL...AND EVEN TORNADOES. THE RISK WAS FOR THE SW AND SOUTH
CENTRAL FORECAST AREA.
A LOW PRESSURE SYSTEM IN THE ROCKIES IS EXPECTED TO MOVE INTO THE
NORTHERN HIGH PLAINS THIS MORNING AND GRADUALLY ORGANIZE AS IT
MOVES INTO WESTERN SOUTH DAKOTA THIS AFTERNOON. THERE WILL BE WARM
AND MOIST SOUTHERLY FLOW OVER THE NORTHERN PLAINS AND UPPER
MIDWEST...INCLUDING THE NORTHLAND. THE MODELS ARE PRIMARILY
INDICATING THAT A WARM/STATIONARY FRONT WILL SET UP OVER EASTERN
NORTH DAKOTA AND NORTHERN MINNESOTA. THIS FRONT AND FRONTOGENESIS
ALOFT WILL CONTRIBUTE TO INCREASING CHANCES FOR SHOWERS AND STORMS
IN ITS AREA LATE THIS MORNING AND THIS AFTERNOON. SOME MODELS ARE
ALSO SUGGESTING ANOTHER BOUNDARY...IN THE FORM OF ANOTHER
WARM/STATIONARY FRONT...COULD SET UP ACROSS THE SOUTHERN FORECAST
AREA. THIS OTHER FRONT WILL ALSO AID THE DEVELOPMENT OF SHOWERS
AND STORMS. SOME MODELS PLACE MORE EMPHASIS ON THE NORTHERN
BOUNDARY AND RESULTING SHOWERS AND STORMS...WHILE OTHERS PLACE
MORE EMPHASIS ON THE SOUTHERN BOUNDARY. SINCE THERE COULD BE
INITIAL CAPPING ISSUES OVER THE SOUTHERN FORECAST AREA DUE TO WARM
AIR ALOFT...I HAVE PCPN INCREASING MORE RAPIDLY NEAR THE NORTHERN
BOUNDARY.
THE ENVIRONMENT WILL SUPPORT THE POTENTIAL FOR STRONG TO SEVERE
STORMS OVER MUCH OF THE FORECAST AREA. MIXED LAYER CAPE COULD
APPROACH OR EXCEED 2000 J/KG LATE THIS AFTERNOON AND EARLY THIS
EVENING...WITH THE HIGHER INSTABILITY OVER THE SW AND SOUTHERN
FORECAST AREA. THE COMBINATION OF THIS INSTABILITY AND AT LEAST
30 TO 45 KNOTS OF DEEP LAYER (0-6 KM) WIND SHEAR WILL SUPPORT THE
DEVELOPMENT OF ORGANIZED SUPERCELLS DURING THE LATE AFTERNOON AND
EARLY EVENING. THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE
AREAS OF NE MINNESOTA SOUTH OF HIGHWAY 2...INCLUDING THE BRAINERD
LAKES REGION...WHERE INSTABILITY WILL LIKELY BE GREATEST WITH
SUFFICIENT SHEAR AND LOCATED NEAR THE SOUTHERN BOUNDARY. THIS IS
WHERE THERE WILL ALSO BE AN INCREASED POTENTIAL FOR TORNADOES.
MOST OF THE MODELS SUGGEST THAT AFTER THE INITIAL HOURS OF
CONVECTION LATE THIS AFTERNOON AND EARLY THIS EVENING...THAT THE
STORMS COULD FORM A COMPLEX WHICH WOULD LIKELY MOVE EAST...TAPPING
INTO THE STRONG INSTABILITY AND 850 HPA FLOW AND MOISTURE
TRANSPORT ACROSS THE SOUTHERN FORECAST AREA. WHILE THE INITIAL
THREAT OF TODAY MAY BE LARGE HAIL AND TORNADOES...THIS WOULD
PROBABLY TRANSITION TO MORE OF A THREAT OF DAMAGING WINDS. THE
PRECIPITABLE WATER VALUES...WHICH COULD REACH THE 1.75 TO 2 INCH
RANGE...ALSO SUPPORT POTENTIAL HEAVY RAIN. SOME AREAS COULD SEE A
QUICK 1 TO 2 INCHES OF RAIN DEPENDING ON THE DEVELOPMENT AND TRACK
OF STORMS.
THE CHANCES OF SHOWERS AND STORMS WILL DECREASE FROM WEST TO EAST
OVERNIGHT AS AXIS OF THE LOW JET...AND THE MOISTURE TRANSPORT
AXIS...SHIFTS TO THE EAST. THE SURFACE LOW IN WESTERN SOUTH DAKOTA
WILL MOVE TO THE SD/MN BORDER BY LATE IN THE NIGHT...AND ITS
INVERTED TROUGH WILL MOVE TO NEAR THE ND/MN BORDER. THERE ARE LOW
CHANCES OF LINGERING SHOWERS AND STORMS OVER THE FAR NW FORECAST
AREA DUE TO THE LINGERING SUBTLE BOUNDARY OVER NORTHERN MINNESOTA
OR NW ONTARIO AND RESIDUAL FRONTOGENESIS ALOFT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 350 AM CDT WED SEP 3 2014
INITIAL FOCUS FOR LONG TERM IS THE TIMING OF THE COLD FRONT
PASSAGE AND TSTM POTENTIAL THURSDAY. HAVE MADE MINOR ADJUSTMENTS
TO PREVIOUS FCST TO REFINE TIMING OF THE WIND SHIFT/POPS FOR A
SLIGHTLY SLOWER FROPA. LATEST ECM/NAM/GFS ARE ALL IN GOOD
AGREEMENT THE COLD FRONT/SFC LOW REACHES THE WRN MN BORDER
THURSDAY MORNING AROUND DAYBREAK...TRACKS EAST ACROSS NORTH-
CENTRAL MINNESOTA THROUGH THE EARLY AFTERNOON...REACHING LOCATIONS
ALONG A LINE FROM KHIB/KDLH/K04W AROUND 00Z...THEN QUICKLY PASSES
OVER THE NRN WISCONSIN ZONES BY MIDNIGHT.
THIS TIMING WILL POSITION MUCH OF THE FORECAST AREA IN THE WARM
SECTOR WITH INCREASING MOISTURE/DEW POINTS FOR MUCH OF THE DAY
THURSDAY. LATEST GUIDANCE SUGGESTS DEW POINTS REACH THE LOW 70S
ACROSS THE ST CROIX RIVER VALLEY AND ACROSS NORTHERN WISCONSIN. IN
ADDITION...THE RESULTING PRESSURE GRADIENT DUE TO THE APPROACHING
FRONT WILL PROMOTE EAST WINDS OVER LAKE SUPERIOR. HAVE LOWERED
TEMPS AND INTRODUCED AREAS OF FOG FOR LOCATIONS ALONG THE NORTH
SHORE AND WESTERN TIP OF LAKE SUPERIOR TO ACCOUNT FOR THE MARINE
AIR MASS.
THE STRONG BAROCLINIC ZONE AND ABUNDANT MOISTURE WILL SUPPORT
STRONG TO SEVERE THUNDERSTORMS ALONG THE FRONT...MAINLY DURING
THE AFTERNOON/EVENING HOURS THURSDAY. HOWEVER...THE LIMITING
FACTOR WILL BE THE NORTHERN EXTENT OF A A STRONG MID-LEVEL CAP.
LATEST NAM BUFR SOUNDING AT KBRD SHOWS H700-H800 TEMPS AROUND 15C.
FURTHER NORTH...TOWARDS KHIB/KELO TEMPERATURES ARE COOLER...BUT
STILL INTRODUCE A LEVEL OF UNCERTAINTY IN THE ABILITY TO TRIGGER
CONVECTION.
IN THE WAKE OF THE COLD FRONT...H85 WINDS ON THE ORDER OF 30-40 KT
WILL ALLOW MUCH COOLER AND DRIER AIR TO SURGE INTO THE
NORTHLAND. THE COLD AIR ALOFT WILL ALLOW FOR FAVORABLE LOW LEVEL
LAPSE RATES THURSDAY NIGHT TO MAINTAIN A FEW THOUSAND FT MIXED
LAYER. HAVE INCREASED WINDS/GUSTS THURS NIGHT AND MAY NEED TO BE
FURTHER INCREASED ON LATER SHIFTS. AT THIS TIME...A PERIOD OF
WINDS GUSTING AROUND 30-35 KT THURSDAY NIGHT IS EXPECTED OVER MUCH
OF THE DLH FORECAST AREA/LAKE SUPERIOR. THE HIGHEST WIND GUSTS ARE
ANTICIPATED ALONG THE NORTH SHORE OF LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1229 PM CDT WED SEP 3 2014
LINE OF THUNDERSTORMS TO THE SOUTH WILL SLOWLY ENCROACH UPON THE
REGION THROUGH THE AFTERNOON. MODEL GUIDANCE IS KEEPING THE STORMS
FROM TRACKING TOO FAR NORTH...BUT WILL CLIP BRD AND DLH AND PUSH
ACROSS HYR THROUGH THE EVENING. A SECONDARY LINE OF WEAKER
CONVECTION WILL DEVELOP OVER NE MN THIS AFTERNOON AND LINGER OVER
THE REGION TONIGHT AS WELL. WILL LIKELY SEE FOG DEVELOP BEHIND THE
SYSTEM WITH LIFR CIGS/VSBYS AND SOME -DZ POSSIBLE ALONG THE NORTH
SHORE AND AROUND DLH. A FEW LIGHT RAIN SHOWERS ARE POSSIBLE
THURSDAY MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 75 62 70 55 / 60 70 40 10
INL 76 57 72 46 / 40 50 50 30
BRD 78 64 76 50 / 70 90 20 20
HYR 78 66 83 52 / 50 90 60 20
ASX 79 63 81 53 / 50 70 70 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
UPDATE...STEWART
SHORT TERM...GROCHOCINSKI
LONG TERM...GRANING
AVIATION...BJT
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1229 PM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 1229 PM CDT WED SEP 3 2014
UPDATED FOR AVIATION DISCUSSION BELOW.
UPDATE ISSUED AT 1110 AM CDT WED SEP 3 2014
UPDATED TO ADD HIGHER POPS TO SOUTHERN COUNTIES OF FCST AREA WITH
PRECIP SLOWLY DRIFTING NORTH.
UPDATE ISSUED AT 950 AM CDT WED SEP 3 2014
UPDATED TO ADJUST POPS ALONG THE SOUTHERN BORDER OF THE FCST AREA
BASED ON NORTHERN EXTENT OF THE PRECIP AREA IN SOUTHERN MN. THERE
IS SOME BACK BUILDING OF THE AREA IN THE SOUTH SO THE QUESTION IS
HOW MUCH WILL THE AREA AFFECT NE MN AND MW WI. IF THERE IS A LONG
ENOUGH BREAK IN THE PRECIP...THIS COULD ALLOW HIGHER DEWPOINTS TO
MOVE UP INTO THE FORECAST AREA. THE SREF AND HRRR IS HINTING AT
SOME DEVELOPMENT ACROSS THE SOUTHERN COUNTIES OF THE FORECAST AREA
AND MOVING NORTH BUT NOT AS MUCH AS EARLIER MODELS THIS MORNING.
THE NEXT 2-4 HOURS WILL INDICATE HOW THE SOUTHERN PRCIP AREA IS
AFFECTING DEVELOPMENT IN THE NORTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT WED SEP 3 2014
THE FOCUS IS ON THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS
THIS AFTERNOON AND TONIGHT. AT THE TIME OF THIS WRITING...THE
STORM PREDICTION CENTER HAD A SLIGHT RISK OF SEVERE STORMS OVER
MOST OF THE FORECAST AREA TODAY...WITH EXCEPTION OF THE FAR NORTH.
THERE IS THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...HEAVY
RAINFALL...AND EVEN TORNADOES. THE RISK WAS FOR THE SW AND SOUTH
CENTRAL FORECAST AREA.
A LOW PRESSURE SYSTEM IN THE ROCKIES IS EXPECTED TO MOVE INTO THE
NORTHERN HIGH PLAINS THIS MORNING AND GRADUALLY ORGANIZE AS IT
MOVES INTO WESTERN SOUTH DAKOTA THIS AFTERNOON. THERE WILL BE WARM
AND MOIST SOUTHERLY FLOW OVER THE NORTHERN PLAINS AND UPPER
MIDWEST...INCLUDING THE NORTHLAND. THE MODELS ARE PRIMARILY
INDICATING THAT A WARM/STATIONARY FRONT WILL SET UP OVER EASTERN
NORTH DAKOTA AND NORTHERN MINNESOTA. THIS FRONT AND FRONTOGENESIS
ALOFT WILL CONTRIBUTE TO INCREASING CHANCES FOR SHOWERS AND STORMS
IN ITS AREA LATE THIS MORNING AND THIS AFTERNOON. SOME MODELS ARE
ALSO SUGGESTING ANOTHER BOUNDARY...IN THE FORM OF ANOTHER
WARM/STATIONARY FRONT...COULD SET UP ACROSS THE SOUTHERN FORECAST
AREA. THIS OTHER FRONT WILL ALSO AID THE DEVELOPMENT OF SHOWERS
AND STORMS. SOME MODELS PLACE MORE EMPHASIS ON THE NORTHERN
BOUNDARY AND RESULTING SHOWERS AND STORMS...WHILE OTHERS PLACE
MORE EMPHASIS ON THE SOUTHERN BOUNDARY. SINCE THERE COULD BE
INITIAL CAPPING ISSUES OVER THE SOUTHERN FORECAST AREA DUE TO WARM
AIR ALOFT...I HAVE PCPN INCREASING MORE RAPIDLY NEAR THE NORTHERN
BOUNDARY.
THE ENVIRONMENT WILL SUPPORT THE POTENTIAL FOR STRONG TO SEVERE
STORMS OVER MUCH OF THE FORECAST AREA. MIXED LAYER CAPE COULD
APPROACH OR EXCEED 2000 J/KG LATE THIS AFTERNOON AND EARLY THIS
EVENING...WITH THE HIGHER INSTABILITY OVER THE SW AND SOUTHERN
FORECAST AREA. THE COMBINATION OF THIS INSTABILITY AND AT LEAST
30 TO 45 KNOTS OF DEEP LAYER (0-6 KM) WIND SHEAR WILL SUPPORT THE
DEVELOPMENT OF ORGANIZED SUPERCELLS DURING THE LATE AFTERNOON AND
EARLY EVENING. THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE
AREAS OF NE MINNESOTA SOUTH OF HIGHWAY 2...INCLUDING THE BRAINERD
LAKES REGION...WHERE INSTABILITY WILL LIKELY BE GREATEST WITH
SUFFICIENT SHEAR AND LOCATED NEAR THE SOUTHERN BOUNDARY. THIS IS
WHERE THERE WILL ALSO BE AN INCREASED POTENTIAL FOR TORNADOES.
MOST OF THE MODELS SUGGEST THAT AFTER THE INITIAL HOURS OF
CONVECTION LATE THIS AFTERNOON AND EARLY THIS EVENING...THAT THE
STORMS COULD FORM A COMPLEX WHICH WOULD LIKELY MOVE EAST...TAPPING
INTO THE STRONG INSTABILITY AND 850 HPA FLOW AND MOISTURE
TRANSPORT ACROSS THE SOUTHERN FORECAST AREA. WHILE THE INITIAL
THREAT OF TODAY MAY BE LARGE HAIL AND TORNADOES...THIS WOULD
PROBABLY TRANSITION TO MORE OF A THREAT OF DAMAGING WINDS. THE
PRECIPITABLE WATER VALUES...WHICH COULD REACH THE 1.75 TO 2 INCH
RANGE...ALSO SUPPORT POTENTIAL HEAVY RAIN. SOME AREAS COULD SEE A
QUICK 1 TO 2 INCHES OF RAIN DEPENDING ON THE DEVELOPMENT AND TRACK
OF STORMS.
THE CHANCES OF SHOWERS AND STORMS WILL DECREASE FROM WEST TO EAST
OVERNIGHT AS AXIS OF THE LOW JET...AND THE MOISTURE TRANSPORT
AXIS...SHIFTS TO THE EAST. THE SURFACE LOW IN WESTERN SOUTH DAKOTA
WILL MOVE TO THE SD/MN BORDER BY LATE IN THE NIGHT...AND ITS
INVERTED TROUGH WILL MOVE TO NEAR THE ND/MN BORDER. THERE ARE LOW
CHANCES OF LINGERING SHOWERS AND STORMS OVER THE FAR NW FORECAST
AREA DUE TO THE LINGERING SUBTLE BOUNDARY OVER NORTHERN MINNESOTA
OR NW ONTARIO AND RESIDUAL FRONTOGENESIS ALOFT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 350 AM CDT WED SEP 3 2014
INITIAL FOCUS FOR LONG TERM IS THE TIMING OF THE COLD FRONT
PASSAGE AND TSTM POTENTIAL THURSDAY. HAVE MADE MINOR ADJUSTMENTS
TO PREVIOUS FCST TO REFINE TIMING OF THE WIND SHIFT/POPS FOR A
SLIGHTLY SLOWER FROPA. LATEST ECM/NAM/GFS ARE ALL IN GOOD
AGREEMENT THE COLD FRONT/SFC LOW REACHES THE WRN MN BORDER
THURSDAY MORNING AROUND DAYBREAK...TRACKS EAST ACROSS NORTH-
CENTRAL MINNESOTA THROUGH THE EARLY AFTERNOON...REACHING LOCATIONS
ALONG A LINE FROM KHIB/KDLH/K04W AROUND 00Z...THEN QUICKLY PASSES
OVER THE NRN WISCONSIN ZONES BY MIDNIGHT.
THIS TIMING WILL POSITION MUCH OF THE FORECAST AREA IN THE WARM
SECTOR WITH INCREASING MOISTURE/DEW POINTS FOR MUCH OF THE DAY
THURSDAY. LATEST GUIDANCE SUGGESTS DEW POINTS REACH THE LOW 70S
ACROSS THE ST CROIX RIVER VALLEY AND ACROSS NORTHERN WISCONSIN. IN
ADDITION...THE RESULTING PRESSURE GRADIENT DUE TO THE APPROACHING
FRONT WILL PROMOTE EAST WINDS OVER LAKE SUPERIOR. HAVE LOWERED
TEMPS AND INTRODUCED AREAS OF FOG FOR LOCATIONS ALONG THE NORTH
SHORE AND WESTERN TIP OF LAKE SUPERIOR TO ACCOUNT FOR THE MARINE
AIR MASS.
THE STRONG BAROCLINIC ZONE AND ABUNDANT MOISTURE WILL SUPPORT
STRONG TO SEVERE THUNDERSTORMS ALONG THE FRONT...MAINLY DURING
THE AFTERNOON/EVENING HOURS THURSDAY. HOWEVER...THE LIMITING
FACTOR WILL BE THE NORTHERN EXTENT OF A A STRONG MID-LEVEL CAP.
LATEST NAM BUFR SOUNDING AT KBRD SHOWS H700-H800 TEMPS AROUND 15C.
FURTHER NORTH...TOWARDS KHIB/KELO TEMPERATURES ARE COOLER...BUT
STILL INTRODUCE A LEVEL OF UNCERTAINTY IN THE ABILITY TO TRIGGER
CONVECTION.
IN THE WAKE OF THE COLD FRONT...H85 WINDS ON THE ORDER OF 30-40 KT
WILL ALLOW MUCH COOLER AND DRIER AIR TO SURGE INTO THE
NORTHLAND. THE COLD AIR ALOFT WILL ALLOW FOR FAVORABLE LOW LEVEL
LAPSE RATES THURSDAY NIGHT TO MAINTAIN A FEW THOUSAND FT MIXED
LAYER. HAVE INCREASED WINDS/GUSTS THURS NIGHT AND MAY NEED TO BE
FURTHER INCREASED ON LATER SHIFTS. AT THIS TIME...A PERIOD OF
WINDS GUSTING AROUND 30-35 KT THURSDAY NIGHT IS EXPECTED OVER MUCH
OF THE DLH FORECAST AREA/LAKE SUPERIOR. THE HIGHEST WIND GUSTS ARE
ANTICIPATED ALONG THE NORTH SHORE OF LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1229 PM CDT WED SEP 3 2014
LINE OF THUNDERSTORMS TO THE SOUTH WILL SLOWLY ENCROACH UPON THE
REGION THROUGH THE AFTERNOON. MODEL GUIDANCE IS KEEPING THE STORMS
FROM TRACKING TOO FAR NORTH...BUT WILL CLIP BRD AND DLH AND PUSH
ACROSS HYR THROUGH THE EVENING. A SECONDARY LINE OF WEAKER
CONVECTION WILL DEVELOP OVER NE MN THIS AFTERNOON AND LINGER OVER
THE REGION TONIGHT AS WELL. WILL LIKELY SEE FOG DEVELOP BEHIND THE
SYSTEM WITH LIFR CIGS/VSBYS AND SOME -DZ POSSIBLE ALONG THE NORTH
SHORE AND AROUND DLH. A FEW LIGHT RAIN SHOWERS ARE POSSIBLE
THURSDAY MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 75 62 70 55 / 60 70 40 10
INL 76 57 72 46 / 40 50 50 30
BRD 78 64 76 50 / 70 80 20 20
HYR 78 66 83 52 / 40 80 60 20
ASX 79 63 81 53 / 50 70 70 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM...GRANING
AVIATION...BJT
AREA FORECAST DISCUSSION
NWS DULUTH MN
1111 AM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 1110 AM CDT WED SEP 3 2014
UPDATED TO ADD HIGHER POPS TO SOUTHERN COUNTIES OF FCST AREA WITH
PRECIP SLOWLY DRIFTING NORTH.
UPDATE ISSUED AT 950 AM CDT WED SEP 3 2014
UPDATED TO ADJUST POPS ALONG THE SOUTHERN BORDER OF THE FCST AREA
BASED ON NORTHERN EXTENT OF THE PRECIP AREA IN SOUTHERN MN. THERE
IS SOME BACK BUILDING OF THE AREA IN THE SOUTH SO THE QUESTION IS
HOW MUCH WILL THE AREA AFFECT NE MN AND MW WI. IF THERE IS A LONG
WENOUGH BREAK IN THE PRECIP...THIS COULD ALLOW HIGHER DEWPOINTS TO
MOVE UP INTO THE FORECAST AREA. THE SREF AND HRRR IS HINTING AT
SOME DEVELOPMENT ACROSS THE SOUTHERN COUNTIES OF THE FORECAST AREA
AND MOVING NORTH BUT NOT AS MUCH AS EARLIER MODELS THIS MORNING.
THE NEXT 2-4 HOURS WILL INDICATE HOW THE SOUTHERN PRCIP AREA IS
AFFECTING DEVELOPMENT IN THE NORTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT WED SEP 3 2014
THE FOCUS IS ON THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS
THIS AFTERNOON AND TONIGHT. AT THE TIME OF THIS WRITING...THE
STORM PREDICTION CENTER HAD A SLIGHT RISK OF SEVERE STORMS OVER
MOST OF THE FORECAST AREA TODAY...WITH EXCEPTION OF THE FAR NORTH.
THERE IS THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...HEAVY
RAINFALL...AND EVEN TORNADOES. THE RISK WAS FOR THE SW AND SOUTH
CENTRAL FORECAST AREA.
A LOW PRESSURE SYSTEM IN THE ROCKIES IS EXPECTED TO MOVE INTO THE
NORTHERN HIGH PLAINS THIS MORNING AND GRADUALLY ORGANIZE AS IT
MOVES INTO WESTERN SOUTH DAKOTA THIS AFTERNOON. THERE WILL BE WARM
AND MOIST SOUTHERLY FLOW OVER THE NORTHERN PLAINS AND UPPER
MIDWEST...INCLUDING THE NORTHLAND. THE MODELS ARE PRIMARILY
INDICATING THAT A WARM/STATIONARY FRONT WILL SET UP OVER EASTERN
NORTH DAKOTA AND NORTHERN MINNESOTA. THIS FRONT AND FRONTOGENESIS
ALOFT WILL CONTRIBUTE TO INCREASING CHANCES FOR SHOWERS AND STORMS
IN ITS AREA LATE THIS MORNING AND THIS AFTERNOON. SOME MODELS ARE
ALSO SUGGESTING ANOTHER BOUNDARY...IN THE FORM OF ANOTHER
WARM/STATIONARY FRONT...COULD SET UP ACROSS THE SOUTHERN FORECAST
AREA. THIS OTHER FRONT WILL ALSO AID THE DEVELOPMENT OF SHOWERS
AND STORMS. SOME MODELS PLACE MORE EMPHASIS ON THE NORTHERN
BOUNDARY AND RESULTING SHOWERS AND STORMS...WHILE OTHERS PLACE
MORE EMPHASIS ON THE SOUTHERN BOUNDARY. SINCE THERE COULD BE
INITIAL CAPPING ISSUES OVER THE SOUTHERN FORECAST AREA DUE TO WARM
AIR ALOFT...I HAVE PCPN INCREASING MORE RAPIDLY NEAR THE NORTHERN
BOUNDARY.
THE ENVIRONMENT WILL SUPPORT THE POTENTIAL FOR STRONG TO SEVERE
STORMS OVER MUCH OF THE FORECAST AREA. MIXED LAYER CAPE COULD
APPROACH OR EXCEED 2000 J/KG LATE THIS AFTERNOON AND EARLY THIS
EVENING...WITH THE HIGHER INSTABILITY OVER THE SW AND SOUTHERN
FORECAST AREA. THE COMBINATION OF THIS INSTABILITY AND AT LEAST
30 TO 45 KNOTS OF DEEP LAYER (0-6 KM) WIND SHEAR WILL SUPPORT THE
DEVELOPMENT OF ORGANIZED SUPERCELLS DURING THE LATE AFTERNOON AND
EARLY EVENING. THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE
AREAS OF NE MINNESOTA SOUTH OF HIGHWAY 2...INCLUDING THE BRAINERD
LAKES REGION...WHERE INSTABILITY WILL LIKELY BE GREATEST WITH
SUFFICIENT SHEAR AND LOCATED NEAR THE SOUTHERN BOUNDARY. THIS IS
WHERE THERE WILL ALSO BE AN INCREASED POTENTIAL FOR TORNADOES.
MOST OF THE MODELS SUGGEST THAT AFTER THE INITIAL HOURS OF
CONVECTION LATE THIS AFTERNOON AND EARLY THIS EVENING...THAT THE
STORMS COULD FORM A COMPLEX WHICH WOULD LIKELY MOVE EAST...TAPPING
INTO THE STRONG INSTABILITY AND 850 HPA FLOW AND MOISTURE
TRANSPORT ACROSS THE SOUTHERN FORECAST AREA. WHILE THE INITIAL
THREAT OF TODAY MAY BE LARGE HAIL AND TORNADOES...THIS WOULD
PROBABLY TRANSITION TO MORE OF A THREAT OF DAMAGING WINDS. THE
PRECIPITABLE WATER VALUES...WHICH COULD REACH THE 1.75 TO 2 INCH
RANGE...ALSO SUPPORT POTENTIAL HEAVY RAIN. SOME AREAS COULD SEE A
QUICK 1 TO 2 INCHES OF RAIN DEPENDING ON THE DEVELOPMENT AND TRACK
OF STORMS.
THE CHANCES OF SHOWERS AND STORMS WILL DECREASE FROM WEST TO EAST
OVERNIGHT AS AXIS OF THE LOW JET...AND THE MOISTURE TRANSPORT
AXIS...SHIFTS TO THE EAST. THE SURFACE LOW IN WESTERN SOUTH DAKOTA
WILL MOVE TO THE SD/MN BORDER BY LATE IN THE NIGHT...AND ITS
INVERTED TROUGH WILL MOVE TO NEAR THE ND/MN BORDER. THERE ARE LOW
CHANCES OF LINGERING SHOWERS AND STORMS OVER THE FAR NW FORECAST
AREA DUE TO THE LINGERING SUBTLE BOUNDARY OVER NORTHERN MINNESOTA
OR NW ONTARIO AND RESIDUAL FRONTOGENESIS ALOFT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 350 AM CDT WED SEP 3 2014
INITIAL FOCUS FOR LONG TERM IS THE TIMING OF THE COLD FRONT
PASSAGE AND TSTM POTENTIAL THURSDAY. HAVE MADE MINOR ADJUSTMENTS
TO PREVIOUS FCST TO REFINE TIMING OF THE WIND SHIFT/POPS FOR A
SLIGHTLY SLOWER FROPA. LATEST ECM/NAM/GFS ARE ALL IN GOOD
AGREEMENT THE COLD FRONT/SFC LOW REACHES THE WRN MN BORDER
THURSDAY MORNING AROUND DAYBREAK...TRACKS EAST ACROSS NORTH-
CENTRAL MINNESOTA THROUGH THE EARLY AFTERNOON...REACHING LOCATIONS
ALONG A LINE FROM KHIB/KDLH/K04W AROUND 00Z...THEN QUICKLY PASSES
OVER THE NRN WISCONSIN ZONES BY MIDNIGHT.
THIS TIMING WILL POSITION MUCH OF THE FORECAST AREA IN THE WARM
SECTOR WITH INCREASING MOISTURE/DEW POINTS FOR MUCH OF THE DAY
THURSDAY. LATEST GUIDANCE SUGGESTS DEW POINTS REACH THE LOW 70S
ACROSS THE ST CROIX RIVER VALLEY AND ACROSS NORTHERN WISCONSIN. IN
ADDITION...THE RESULTING PRESSURE GRADIENT DUE TO THE APPROACHING
FRONT WILL PROMOTE EAST WINDS OVER LAKE SUPERIOR. HAVE LOWERED
TEMPS AND INTRODUCED AREAS OF FOG FOR LOCATIONS ALONG THE NORTH
SHORE AND WESTERN TIP OF LAKE SUPERIOR TO ACCOUNT FOR THE MARINE
AIR MASS.
THE STRONG BAROCLINIC ZONE AND ABUNDANT MOISTURE WILL SUPPORT
STRONG TO SEVERE THUNDERSTORMS ALONG THE FRONT...MAINLY DURING
THE AFTERNOON/EVENING HOURS THURSDAY. HOWEVER...THE LIMITING
FACTOR WILL BE THE NORTHERN EXTENT OF A A STRONG MID-LEVEL CAP.
LATEST NAM BUFR SOUNDING AT KBRD SHOWS H700-H800 TEMPS AROUND 15C.
FURTHER NORTH...TOWARDS KHIB/KELO TEMPERATURES ARE COOLER...BUT
STILL INTRODUCE A LEVEL OF UNCERTAINTY IN THE ABILITY TO TRIGGER
CONVECTION.
IN THE WAKE OF THE COLD FRONT...H85 WINDS ON THE ORDER OF 30-40 KT
WILL ALLOW MUCH COOLER AND DRIER AIR TO SURGE INTO THE
NORTHLAND. THE COLD AIR ALOFT WILL ALLOW FOR FAVORABLE LOW LEVEL
LAPSE RATES THURSDAY NIGHT TO MAINTAIN A FEW THOUSAND FT MIXED
LAYER. HAVE INCREASED WINDS/GUSTS THURS NIGHT AND MAY NEED TO BE
FURTHER INCREASED ON LATER SHIFTS. AT THIS TIME...A PERIOD OF
WINDS GUSTING AROUND 30-35 KT THURSDAY NIGHT IS EXPECTED OVER MUCH
OF THE DLH FORECAST AREA/LAKE SUPERIOR. THE HIGHEST WIND GUSTS ARE
ANTICIPATED ALONG THE NORTH SHORE OF LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 650 AM CDT WED SEP 3 2014
A WARM FRONT WILL LIFT OVER THE FORECAST AREA TODAY...BRINGING
LOWERING CEILINGS AND INCREASING THUNDER CHANCES THROUGH THE
AFTERNOON AND EVENING. BY 06Z...WIDESPREAD MVFR/IFR CONDITIONS
WILL BE FOUND AFTER 06Z AS LOW CLOUDS AND SCATTERED SHOWERS AND
THUNDERSTORMS ARE FOUND ACROSS THE REGION. HAVE BROUGHT IN LIFR
CONDITIONS TO KDLH AFTER 06Z...AS WINDS TURN OUT OF THE EAST AND
ELEVATED DEW POINTS ALLOW FOR FOG/-DZ.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 75 62 70 55 / 60 70 40 10
INL 76 57 72 46 / 40 50 50 30
BRD 78 64 76 50 / 70 80 20 20
HYR 78 66 83 52 / 40 80 60 20
ASX 79 63 81 53 / 50 70 70 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
UPDATE...STEWART
SHORT TERM...GROCHOCINSKI
LONG TERM...GRANING
AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1234 PM CDT WED SEP 3 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM CDT WED SEP 3 2014
UPPER AIR AND SATELLITE DATA SHOWING THE AREA CONTINUING TO BE
INFLUENCED BY ZONAL FLOW...AS HIGH PRESSURE EXTENDS ACROSS THE SRN
CONUS AND BROAD TROUGHING IS IN PLACE NEAR/NORTH OF THE CANADIAN
BORDER...THOUGH AN AREA OF LOW PRESSURE IS PUSHING ITS WAY FURTHER
INLAND FROM THE PAC NW COAST. AS WAS SHOWN BY MODELS...CONVECTION
DEVELOPED EARLIER ACROSS CENTRAL KANSAS...IN RESPONSE TO A WEAK
DISTURBANCE AS WELL AS INCREASED LIFT VIA WARM AIR/MOISTURE
ADVECTION ASSOCIATED WITH A STRONGER LLJ. EARLY ON THE FAR
SOUTHEASTERN CORNER OF MITCHELL COUNTY WAS CLIPPED BY THIS
ACTIVITY...BUT SINCE THEN HAS REMAINED OVER ERN KS. THERE IS A
COUPLE ISOLATED SHOWERS OVER WESTERN KS...AND THE HRRR/RAP HINT AT
SOME ADDITIONAL ACTIVITY POSSIBLY LINGERING INTO THE MID MORNING
HOURS...SO WILL HAVE TO MONITOR HOW THIS ACTIVITY EVOLVES OVER
NEXT FEW HOURS. SATELLITE IMAGERY ALSO SHOWING SOME LOW/MID LEVEL
STRATUS STARTING TO INCREASE IN COVERAGE...BUT MODELS DIFFER SOME
ON HOW EXPANSIVE IT WILL END UP BEING. AT THE SURFACE...THE CWA IS
SET UP BETWEEN HIGH PRESSURE AFFECTING MUCH OF THE ERN CONUS...AND
A TROUGH OF LOW PRESSURE OVER THE HIGH PLAINS. WINDS REMAIN
SOUTHERLY...WITH SPEEDS RANGING FROM 5 TO 15 MPH. TEMPS ARE MORE
MILD THAN 24 HRS AGO...WITH 3 AM TEMPS IN THE MID 60S TO LOWER
70S.
THE MAIN STORY IN THE SHORT TERM PERIOD LIES WITH
TEMPERATURES...AS TODAY IS EXPECTED TO BE THE WARMEST OVER THE
NEXT 7. IN THE UPPER LEVELS...MODELS IN GOOD AGREEMENT SHOWING THE
FLOW TRANSITIONING TO MORE SOUTHWESTERLY AS THAT ABOVE MENTION PAC
NW DISTURBANCE SHIFTS FURTHER EASTWARD INTO THE NRN ROCKIES. WHILE
NOT EXPECTING MUCH IN THE WAY OF PRECIP CHANCES THROUGH TONIGHT
/THOUGH CHANCES ARE NOT ZERO/...THIS PATTERN WILL HELP TO CONTINUE
THE ADVECTION OF WARMER AIR ALOFT INTO THE REGION. THIS WILL
CONTINUE RIGHT ON INTO THE OVERNIGHT HOURS AS THE ASSOCIATED SFC
COLD FRONT CREEPS IN FROM THE WEST. BY SUNRISE THURS...MODEL
TIMING ISNT BAD...SHOWING THE FRONT DRAPED ACROSS THE NWRN CORNER
OF THE CWA.
TEMPERATURES FOR TODAY ARE A LITTLE TRICKY...AS SOME MODELS
SHOWING POOLING OF MOISTURE/HIGHER DPTS IN THE SOMEWHAT USUAL
PLACES FOR OUR CWA...ROUGHLY THE NERN THIRD OR SO...WITH DPTS IN
THE LOWER 70S. THOSE HIGHER DPTS MAY KEEP TEMPS DOWN A TOUCH IN
THOSE AREAS...AND HAVE FORECAST HIGHS RIGHT AROUND 90. FURTHER
SW...THINKING THAT TEMPS WILL REACH INTO THE MID/UPPER 90S WITH
DPTS IN THE LOWER 60S. NOT BUYING INTO THE RAP WHICH IS SHOWING
LOW/MID 50S BY MID AFTERNOON DOWN THERE...WITH TEMPS THEN CLIMBING
INTO THE LOW 100S. SOMETHING FOR THE DAY SHIFT TO WATCH THOUGH. AS
WE GET INTO TONIGHT...WITH THE CONTINUED SOUTHERLY FLOW EXPECTED
THROUGH THE MAJORITY OF THE NIGHT...OVERNIGHT LOWS LOOK TO REMAIN
MILD IN THE MID 60S TO MID 70S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 417 AM CDT WED SEP 3 2014
MAIN ISSUE WILL BE POTENTIAL FOR PRECIPITATION.
WE BEGIN THE LONG TERM ON THURSDAY UNDER UPPER LEVEL SOUTHWEST
FLOW WITH A SUBTROPICAL HIGH IN THE SOUTHEASTERN UNITED STATES.
AND A POSITIVELY TILTED TROUGH OVER THE NORTHWESTERN UNITED
STATES.
MOST IF NOT ALL OF THURSDAY SHOULD BE DRY...DESPITE A SURFACE COLD
FRONT MAKING ITS WAY SLOWLY SOUTH AS NUMERICAL MODELS CONTINUE
TO SHOW POST-FRONTAL PRECIPITATION DEVELOPING MAINLY THURSDAY
EVENING CLOSER TO THE VICINITY OF THE UPPER LEVEL JET
STREAK...WHICH WILL NUDGE SOUTH OVER TIME...AND IN TURN PUSHING
THE COLD FRONT FARTHER SOUTH.
INSTABILITY EVENTUALLY WANES AND THERE WILL BE LESS OF A
THUNDERSTORM CHANCE HEADING INTO FRIDAY AND TOOK OUT THUNDER BY
LATE EVENING FRIDAY NIGHT INTO SATURDAY.
THE FRONT IS STILL EXPECTED TO MAKE A RETURN AS THE SURFACE HIGH
THAT HELPED PUSH THE COLD FRONT SOUTH...MAKES A FAIRLY QUICK
RETREAT TO THE EAST...ALLOWING THE FRONT TO RETURN NORTH AS A
WARM FRONT.
ANOTHER COLD FRONT TUESDAY AFTERNOON/NIGHT WILL BRING IN SOME
COOLER WEATHER FOR WEDNESDAY.
THERE COULD BE ENOUGH OF A COMBINATION OF SHEAR AND INSTABILITY
FOR STRONG TO SEVERE THUNDERSTORMS ANYWHERE FROM SUNDAY NIGHT
INTO TUESDAY...BUT IT WOULD BE A TOUGH CALL TO NAIL ANYTHING DOWN
RIGHT NOW.
FOR TEMPERATURES...I WENT WITH CONSRAW FOR LOWS THURSDAY NIGHT AND
FRIDAY NIGHT. NAM FOR HIGHS THURSDAY AND BCCONSRAW FOR HIGHS
FRIDAY...WHICH ARE CONSIDERABLY COOLER. IN FACT...FRIDAY SHOULD
FEEL RATHER FALL-LIKE. OTHER NUMERICAL MODEL SOLUTIONS HAVE NOT
CAUGHT ON LIKE THE BCCONSRAW HAS...BUT I STRONGLY SUSPECT THAT
THEY WILL SOON...CONSIDERING THE TRACK RECORD OF THIS SOLUTION THE
DAY AFTER A COLD FRONT PASSAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1229 PM CDT WED SEP 3 2014
PERSISTENT MVFR CIGS THIS MORNING ARE EXPECTED TO DISSIPATE OVER
THE NEXT FEW HOURS AS SATELLITE IMAGERY IS CONTINUING TO SHOW THIS
AREA OF CLOUD COVER SLOWLY ERODING. OTHERWISE...EXPECT MAINLY
CLEAR SKIES ONCE THE STRATUS DOES BURN OFF...WITH OCCASIONALLY
GUSTY SOUTHERLY WINDS TO 25 KTS OR SO. OVERNIGHT...EXPECT THE
POSSIBILITY OF SOME MARGINAL WIND SHEAR AS THE LOW LEVEL JET
INCREASES...AND INCLUDED THIS MENTION AT BOTH SITES AS WELL. A
STRONG COLD FRONT IS THEN EXPECTED TO CROSS THE TERMINALS BETWEEN
04/15Z-04/18Z...AND INDICATED A WIND SHIFT AHEAD OF THIS FRONT
TOWARDS THE TAIL END OF THE VALID TAF PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...ADO
LONG TERM...HEINLEIN
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS RALEIGH NC
125 PM EDT WED SEP 3 2014
.SYNOPSIS...A SURFACE TROUGH WILL BE LOCATED OVER CENTRAL NORTH
CAROLINA THIS AFTERNOON AS A COLD FRONT REMAINS JUST TO OUR NORTH.
HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR THE REMAINDER OF THE
WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM WEDNESDAY...
THE LATEST SURFACE ANALYSIS SHOWED A SURFACE FRONT OVER NORTHERN
VIRGINIA WITH SURFACE TROUGHS CLOSE TO THE VIRGINIA BORDER EXTENDING
WEST TO EAST...AND OVER THE WESTERN PART OF CENTRAL NORTH CAROLINA.
WIND SHEAR WAS WEAK AND SHOULD REMAIN SO THROUGH THE REST OF THE
DAY...WITH RAP FORECAST 0-3KM VALUES ON THE ORDER OF 10KT OR LESS.
THE LATEST SPC MESOANALYSIS SHOWED GOOD CIN OVER THE WESTERN
PIEDMONT WITH INSTABILITY...TO 2000J/KG...ALONG THE IMMEDIATE COAST.
THE RAP FORECASTS THIS CIN...ASSOCIATED WITH A LOW-LEVEL CAP AND
GOOD DEW POINT SPREADS SUCH AS NOTED ON THE 12Z KGSO SOUNDING...
ERODING THIS AFTERNOON AROUND 20Z. WHILE IN THE MID-LEVELS THERE
SHOULD BE A WEAK SHEAR AXIS AND VORTICITY CLOSER TO THE VIRGINIA
BORDER THIS AFTERNOON...BETTER LOW-LEVEL FORCING IS EXPECTED IN
SURFACE TROUGHINESS CLOSER TO THE COASTAL PLAIN WHERE THE
INSTABILITY SHOULD ALSO BE GREATER...ON THE ORDER OF 1500J/KG THIS
AFTERNOON BASED ON RAP SOUNDINGS. THE RAP FORECASTS THE BETTER LIFT
IN THAT AREA AS WELL...GRADUALLY PROPAGATING WEST IN THE LIGHT WINDS
AND WEAK SHEAR. THE VARIETIES OF HRRR WRF GUIDANCE LEAN TOWARD
INITIAL DEEP CONVECTIVE DEVELOPMENT TOWARD INTERSTATE 95 GRADUALLY
PROPAGATING NORTHWEST...STRUGGLING TO MAKE IT INTO THE TRIAD WHERE
OVERALL STABILITY SHOULD BE GREATER. FOR THE MORNING UPDATE...
DELAYED THE ONSET OF ISOLATED TO SCATTERED POPS AND TRENDED ANY TO
LATE IN THE DAY AND INTO THIS EVENING OVER THE NORTHWEST PIEDMONT.
GIVEN DCAPE FORECAST AT A MAXIMUM AROUND 700J/KG THIS AFTERNOON...
AN ISOLATED STORM COULD PRODUCE A STRONG WIND GUST...BUT INSTANCES
OF SUCH SHOULD BE PULSE-LIKE IN WEAK SHEAR AND WEAK WINDS ALOFT.
WITH GOOD SUN THROUGH THE MORNING AND A FAST RISE TO TEMPERATURES...
IN SEVERAL LOCATIONS RAISED MAXES A DEGREE OR TWO...FOR HIGHS OF 90
TO 95. APPARENT TEMPERATURES...LIKE IN THE HWO...SHOULD BE WITHIN
A DEGREE OR TWO OF 100 EAST OF ABOUT U.S. 1.
CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE
COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO
SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER
60S AND LOWER 70S.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 305 AM WEDNESDAY...
THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A
SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS
HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE
AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION
SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR
SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED
COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL
THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH
NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL
INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN
THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 330 AM WEDNESDAY...
THE SUB-TROPICAL RIDGE WILL BRIEFLY EXPAND NORTH INTO THE OH VALLEY
AND MIDDLE ATLANTIC...AND CONSEQUENTLY CAUSE THE MID LEVEL SHEAR AND
MOIST AXIS SETTLING INTO CENTRAL NC THIS MORNING...TO WEAKEN AND BOW
NORTH INTO VA FRI-SAT. MEDIUM RANGE ENSEMBLE GUIDANCE SUGGESTS THE
SUB-TROPICAL RIDGE WILL THEN WEAKEN AND BECOME SUPPRESSED...BY A
PAIR OF SHORTWAVE TROUGHS FORECAST TO CROSS THE NE US AND SE CANADA
IN PROGRESSIVE FLOW ALOFT THROUGH THE END OF THE WEEKEND. GUIDANCE
IS ALSO IN AGREEMENT THAT SOME DEGREE OF TROUGHING WILL BE LEFT
BEHIND IN A POSITIVE TILT FASHION OVER THE MIDDLE ATLANTIC...THOUGH
THE DEGREE OF WHICH REMAINS UNCERTAIN DUE TO ABOVE AVERAGE MODEL
SPREAD OF THE H5 PATTERN BY DAYS 6-7 (MON-TUE). THE EBB AND FLOW OF
THE PATTERN ALOFT...AND ASSOCIATED SUPPRESSION OF THE SUB-TROPICAL
RIDGE...WILL ALLOW THE POLAR FRONT TO SETTLE SE THROUGH CENTRAL NC
CENTERED AROUND THE DAY SUNDAY...BEFORE SLOWING AS IT DRIFTS
OFFSHORE AND INTO THE VICINITY OF THE GULF STREAM THROUGH MID-WEEK.
A WEAK WAVE OF LOW PRESSURE...OR TWO...ARE APT TO DEVELOP ALONG THE
SLOWING FRONT...AS THE AFOREMENTIONED POSITIVELY TILTED TROUGH ALOFT
INTERACTS WITH SEASONABLY STRONG BAROCLINICITY DRIVEN BY THE
INCOMING COOL/DRY CANADIAN AIR MASS INTO THE WARM/MOIST GULF STREAM
WATERS.
FRI-SAT: A PATTERN OF WEAK SYNOPTIC-SCALE ASCENT AHEAD OF THE
AFOREMENTIONED POLAR FRONT WILL FAVOR NEAR CLIMO PROBABILITIES OF
DIURNALLY-DRIVEN CONVECTION ALONG THE SEA BREEZE AND MOUNTAINS...
BOTH OF WHICH WILL BE APT TO PROPAGATE INTO THE WESTERN AND EASTERN
EDGES OF THE RAH CWFA EACH AFTERNOON AND EVENING. THE DISSIPATION
AND NORTHWARD DEPARTURE OF MID-HIGH CLOUDINESS ASSOCIATED WITH THE
AFOREMENTIONED SHEAR AXIS ALOFT...RESULTING FROM THE BRIEFLY
BUILDING SUB-TROPICAL RIDGE...SHOULD ALLOW FULL-SUN (OR NEARLY SO)
H85 TEMPS IN THE 17-18C RANGE TO BE REALIZED...SUPPORTIVE OF HIGHS
OF 88 TO 93 DEGREES. SAT NIGHT-SUN: THE BEST CHANCE OF SHOWERS AND
STORMS DURING THE LONG TERM PERIOD WILL UNDOUBTEDLY ACCOMPANY THE
ARRIVAL/PASSAGE OF THE POLAR FRONT...ONE WHOSE LOW LEVEL FRONTAL
CIRCULATION WILL BE SUPPORTED THROUGH THE MID-UPPER LEVELS BY
PERSISTENT RIGHT ENTRANCE REGION UPPER JET FORCING. THE COMBINATION
OF INCREASING MID-HIGH CLOUDS AND NUMEROUS TO WIDESPREAD SHOWERS AND
STORMS SHOULD HOLD TEMPERATURES GENERALLY IN THE LOWER TO MIDDLE
80S.
SUN NIGHT-MON NIGHT: SUBSIDENCE DRYING AND LESSENING PROBABILITIES
OF RAIN WILL DEVELOP FROM NW TO SE...BUT NORTHEASTERLY LOW-MID LEVEL
FLOW ON THE WEST SIDE OF THE FRONTAL ZONE AND PROBABLE WAVES OF LOW
PRESSURE WILL RESULT IN MOSTLY CLOUDY CONDITIONS AND A CHANCE OF
RAIN OVER THE EASTERN CWFA...RANGING TO PARTIAL SUNSHINE AND
GENERALLY DRY CONDITIONS OVER THE WESTERN PIEDMONT. COOLER WITH
HIGHS IN THE UPPER 70S TO LOWER 80S.
TUE: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE NORTHEASTERLY
FLOW...AND INCREASING AMOUNTS OF SUNSHINE. MILD WITH HIGHS AGAIN IN
THE UPPER 70S TO LOWER OR PERHAPS MIDDLE 80S.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 125 PM WEDNESDAY...
A MODERATELY MOIST AND UNSTABLE AIR MASS WILL SUPPORT THE
DEVELOPMENT OF SCATTERED CONVECTION LATE THIS AFTERNOON THROUGH THIS
EVENING. THE CONVECTION WILL MOST LIKELY DEVELOP INITIALLY IN THE
VICINITY OF KFAY AND KGSB. OUTFLOWS FROM THIS AREA OF CONVECTION
WILL TRIGGER ADDITIONAL CONVECTION IN THE VICINITY OF KRWI AND KRDU
PRIOR TO SUNSET. ISOLATED TO SCATTERED CONVECTION MAY ALSO OCCUR IN
VICINITY OF KINT AND KGSO BY THIS EVENING. EXPECT BRIEF INSTANCES OF
MVFR/IFR CEILING AND VISIBILITIES IN PROXIMITY OF THE STORMS. AN
ISOLATED WIND GUSTS NEAR 40KTS MAY ALSO OCCUR.
BULK OF CONVECTION WILL DIMINISH BEFORE MIDNIGHT. EXPECT AREAS OF
MVFR/IFR CEILINGS TO DEVELOP PRIOR TO SUNRISE WITH THE NEAR TERM
MODELS FAVORING THE PIEDMONT/KINT-KGSO-KRDU TERMINALS WITH THE
GREATEST LIKELIHOOD OF ADVERSE AVIATION WEATHER CONDITIONS. MVFR
CEILINGS APPEAR TO BE A GOOD PROBABILITY FOR MOST SITES EARLY
THURSDAY MORNING WITH CEILINGS LIFTING INTO THE LOW END VFR CATEGORY
BY 16Z.
ANOTHER ROUND OF SCATTERED THUNDERSTORMS IS EXPECTED THURSDAY
AFTERNOON WITH THE GREATEST PROBABILITY OVER THE NORTHERN PIEDMONT
INCLUDING KGSO...KINT AND KRDU.
EXPECT MAINLY VFR CONDITIONS FRIDAY AND SATURDAY WITH A PERIOD OF
EARLY MORNING LOW CLOUDS AND FOG ANTICIPATED EACH DAY....AND
ISOLATED CONVECTION EACH AFTERNOON.
AN APPROACHING COLD FRONT WILL INCREASE THE THREAT FOR SCATTERED
SHOWERS AND THUNDERSTORMS SUNDAY AND MONDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF/BLS
SHORT TERM...BLS
LONG TERM...MWS
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
332 PM CDT WED SEP 3 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 319 PM CDT WED SEP 3 2014
CONCERN REMAINS HOW FAR NORTH CONVECTION GETS INTO SOUTHEASTERN
FCST AREA LATE THIS AFTN/EVE AND HOW MUCH CONVECTION/PRECIP
DEVELOPS IN WRN ND THIS EVE AND MOVES EAST OVERNIGHT. RAP/HRRR AND
NAM12 HAVE BEEN DOING REASONABLE IN THEIR DEPICTION OF CONVECTION
IN CNTRL MN NORTH OF THE WARM FRONT. OBS INDICATE LIKELY WARM
FRONT FROM ABOUT WATERTOWN TO CANBY MN THEN TOWARD HUTCHINSON MN
THEN TO THE TWIN CITIES. IT HAS BEEN MOVING NORTHWARD. RAP SHOWS
LOW LEVEL JET FEEDING INTO BAND OF STORMS THAT HAS BEEN SLOWLY
LIFTING NORTHEAST THRU CNTRL MN TURNING A BIT MORE SOUTHWEST TO
NORTHEAST ORIENTATION AFTER 00Z AND THUS FOCUS OF PRECIP WILL
SHIFT EAST. REGIONAL RADARS SHOWING NOW SOME DEVELOPING SOUTHWEST
OF LINE INTO THE WARM SECTOR WEST OF WILMAR..THOUGH IT IS WEAK
NOW. IDEA FROM EARLIER SWOMCD IS FOR ACTIVITY TO INCREASE IN THE
AREA NORTHWEST AND WEST OF THE TWIN CITIES NEXT FEW HOURS. IT DOES
APPEAR MORE AND MORE LIKELY THAT ONLY THE FAR SOUTHEASTERN FCST
AREA WILL HAVE ANY IMPACTS FROM THESE STORMS AND THAT MOST WILL
STAY JUST SOUTHEAST OF OUR AREA. THUS TRIMMED POPS SOME BUT DID
KEEP SEVERE MENTION AT LEAST FOR NOW INTO THE EVE IN FAR
SOUTHEASTERN FCST AREA. REST OF THE AREA DRY THRU MID EVENING.
THEN WHAT HAPPENS IS IN QUESTION. RAP SHOWS A DEVELOPING LOW LEVEL
JET AND QUITE STRONG 850 THETA-E ADVECTION AND AN AREA OF
SHOWWALTERS TO -10C MOVING NORTH INTO SE ND 06Z AND JUST
AFTERWARDS. MAIN FORCING WILL BE MORE NORTHWEST TOWARD UPPER LOW
IN SOUTHEASTERN SASK. MODELS NOT EXCITED ABOUT TOO MUCH IN THIS
ELEVATED UNSTABLE LAYER AS IT MOVES INTO SE ND OVERNIGHT BUT AREA
IS IN FAVORABLE POSITION OF LOW LEVEL JET (LEFT QUAD) AND STRONG
INSTABILITY GRADIENT SO WOULDNT BE SUPRISED IF TSTMS DEVELOP
OVERNIGHT AHD OF COLD FRONT IN A MORE WIDESPREAD FASHION THAN
MODEL ADVERTISES.
ANYHOW....DID KEEP SEVERE MENTION OVERNIGHT PER DAY 1 SLIGHT RISK
OVER CNTRL INTO SE ND AND THIS CAN BE ADJUSTED AS NEEDED. IF 850
MB SHOWWALTERS AND LOW LEVEL JET ARE ACCURATE THEN WOULD BE ENOUGH
FOR SOME SEVERE HAILERS. MU CAPES INTHE 2500 J/KG RANGE IN SE ND.
LESS INSTABILITY FARTHER NORTH BUT MAYBE A BIT BETTER CHC OF A
BAND OF SHOWERS/STORMS LATE NIGHT INTO EARLY THURSDAY. PRECIP WILL
EXIT NW MN THURSDAY AFTN...THEN DRIER AND COOLER AIR MOVES IN THU
NIGHT. THOUGH SOME WRAPAROUND CLOUD COVER PSBL ESP IN NW MN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 319 PM CDT WED SEP 3 2014
HIGH PRESSURE IN CONTROL FRIDAY WITH LIKELY DIURNAL CU WITH COOLER
AIR ALOFT.
FOR FRI NIGHT INTO TUESDAY...
A NORTHWEST FLOW PATTERN ALOFT...VOID OF ANY APPRECIABLE MOISTURE
TRANSPORT INTO THE AREA...WILL KEEP A DRY AND COOL AIR MASS IN PLACE
THROUGH THE UPCOMING WEEKEND. THE UPPER AIR PATTERN BECOMES ZONAL
SUNDAY AND TURNS TO THE SOUTHWEST SUNDAY NIGHT...WITH LEE SIDE LOW
PRESSURE MOVING INTO THE PLAINS ON MONDAY. THIS WILL OPEN UP THE
GULF FOR INCREASED MOISTURE TRANSPORT INTO THE AREA AND BRING MORE
ACTIVE WEATHER FOR THE EARLY TO MIDDLE PART OF NEXT WEEK.
TEMPERATURES WILL TYPICALLY BE RIGHT AT OR SLIGHTLY COOLER THAN
SEASONAL NORMS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 113 PM CDT WED SEP 3 2014
VFR CONDS WILL CONTINUE THROUGH THE DAY AND INTO THE LATE
EVENING. THUNDERSTORMS ARE THEN EXPECTED TO SPREAD ACROSS THE AREA
BY EARLY THU MORNING...WITH CIGS GENERALLY REMAINING VFR EXCEPT IN
VCNTY OF TSTMS. WILL KEEP VCTS IN ALL TAF SITES.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...RIDDLE
LONG TERM... RIDDLE/SPEICHER
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS TULSA OK
604 PM CDT WED SEP 3 2014
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS ARE EXPECTED THROUGH THE ENTIRE TAF PERIOD
AT ALL SITES.
&&
.PREV DISCUSSION... /ISSUED 353 PM CDT WED SEP 3 2014/
DISCUSSION...
WARM TEMPERATURES AND BREEZY SOUTHERLY WINDS WERE COMMON ACROSS
EASTERN OKLAHOMA AND NORTHWEST ARKANSAS THIS AFTERNOON AS HIGH
PRESSURE CONTINUED TO HOLD OVER THE SOUTHERN PLAINS. SOME
SCATTERED CONVECTION HAD DEVELOPED OVER FAR SOUTHEAST KANSAS LATE
THIS AFTERNOON...AND THE LATEST HRRR TRIES TO DEVELOP THIS PRECIP
AND PUSH IT SOUTHEAST INTO NORTHWEST/NORTH CENTRAL OKLAHOMA THIS
EVENING AND OVERNIGHT. WILL KEEP POPS BELOW MENTIONABLE CRITERIA
FOR NOW AS MOST OF THIS ACTIVITY SHOULD REMAIN NORTHWEST OF THE
CWA. EVENING SHIFT WILL NEED TO MONITOR FOR ANY CHANGING
CONDITIONS.
HOT TEMPERATURES AND BREEZY SOUTH SOUTHWESTERLY WINDS WILL
CONTINUE ACROSS THE CWA THURSDAY BEFORE A COLD FRONT IS EXPECTED
TO MOVE INTO THE REGION FRIDAY. A WAVE MOVING EASTWARD ALONG THE
U.S./CANADA BORDER WILL PUSH A TRAILING COLD FRONT SOUTHEASTWARD
THROUGH THE PLAINS AND INTO THE CWA DURING THE DAY FRIDAY. CHANCES
FOR SHOWERS AND THUNDERSTORMS BECOME POSSIBLE FRIDAY MORNING AS
THE FRONT NEARS THE REGION AND SHOULD INCREASE IN COVERAGE FRIDAY
AFTERNOON/EVENING WHILE THE FRONT PUSHES INTO THE CWA. CONDITIONS
AHEAD OF THE FRONT AND PRECIP SHOULD CONTINUE TO BE WARM WITH
SOUTHWESTERLY WINDS.
THE FRONTAL BOUNDARY IS FORECAST TO MOVE THROUGH THE REGION FRIDAY
NIGHT AND SATURDAY WITH CONTINUED CHANCES FOR SHOWERS AND
THUNDERSTORMS. POST FRONTAL PRECIP WILL BE POSSIBLE SATURDAY
NIGHT INTO SUNDAY BEFORE THE UPPER LEVEL TROF AXIS ASSOCIATED WITH
THE WAVE OVER SOUTHERN CANADA MOVES OUT OF THE PLAINS. IN THE WAKE
OF THE EXITING TROF...COOLER TEMPS AND NORTHERLY WINDS ARE
EXPECTED ACROSS THE REGION INTO THE START OF THE NEXT WORK WEEK.
SOUTHERLY WINDS QUICKLY RETURN WITH WARMER TEMPERATURES AGAIN FOR
THE MIDDLE PART OF NEXT WEEK AHEAD OF A LONGWAVE TROF FORECAST
TO MOVE OUT OF SOUTHERN CANADA INTO THE PLAINS. LATEST GFS AND
ECMWF DISAGREE ON TIMING OF THIS NEXT WAVE AND ASSOCIATED COLD
FRONT INTO THE CWA. THE ECMWF IS ABOUT 12-24 HRS FASTER COMPARED
TO THE GFS. WILL USE A BLENDED MODEL SOLUTION ALONG WITH PREVIOUS
FORECAST...PUSHING THE FRONT THROUGH WEDNESDAY NIGHT AND THURSDAY.
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL AGAIN BECOME POSSIBLE
MID WEEK AND CONTINUE INTO THE SECOND HALF OF NEXT WEEK AS THE
FRONT MOVES THROUGH. COOLER TEMPS WILL AGAIN BE POSSIBLE LATE NEXT
WEEK.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...23
AREA FORECAST DISCUSSION
NWS TULSA OK
353 PM CDT WED SEP 3 2014
.DISCUSSION...
WARM TEMPERATURES AND BREEZY SOUTHERLY WINDS WERE COMMON ACROSS
EASTERN OKLAHOMA AND NORTHWEST ARKANSAS THIS AFTERNOON AS HIGH
PRESSURE CONTINUED TO HOLD OVER THE SOUTHERN PLAINS. SOME
SCATTERED CONVECTION HAD DEVELOPED OVER FAR SOUTHEAST KANSAS LATE
THIS AFTERNOON...AND THE LATEST HRRR TRIES TO DEVELOP THIS PRECIP
AND PUSH IT SOUTHEAST INTO NORTHWEST/NORTH CENTRAL OKLAHOMA THIS
EVENING AND OVERNIGHT. WILL KEEP POPS BELOW MENTIONABLE CRITERIA
FOR NOW AS MOST OF THIS ACTIVITY SHOULD REMAIN NORTHWEST OF THE
CWA. EVENING SHIFT WILL NEED TO MONITOR FOR ANY CHANGING
CONDITIONS.
HOT TEMPERATURES AND BREEZY SOUTH SOUTHWESTERLY WINDS WILL
CONTINUE ACROSS THE CWA THURSDAY BEFORE A COLD FRONT IS EXPECTED
TO MOVE INTO THE REGION FRIDAY. A WAVE MOVING EASTWARD ALONG THE
U.S./CANADA BORDER WILL PUSH A TRAILING COLD FRONT SOUTHEASTWARD
THROUGH THE PLAINS AND INTO THE CWA DURING THE DAY FRIDAY. CHANCES
FOR SHOWERS AND THUNDERSTORMS BECOME POSSIBLE FRIDAY MORNING AS
THE FRONT NEARS THE REGION AND SHOULD INCREASE IN COVERAGE FRIDAY
AFTERNOON/EVENING WHILE THE FRONT PUSHES INTO THE CWA. CONDITIONS
AHEAD OF THE FRONT AND PRECIP SHOULD CONTINUE TO BE WARM WITH
SOUTHWESTERLY WINDS.
THE FRONTAL BOUNDARY IS FORECAST TO MOVE THROUGH THE REGION FRIDAY
NIGHT AND SATURDAY WITH CONTINUED CHANCES FOR SHOWERS AND
THUNDERSTORMS. POST FRONTAL PRECIP WILL BE POSSIBLE SATURDAY
NIGHT INTO SUNDAY BEFORE THE UPPER LEVEL TROF AXIS ASSOCIATED WITH
THE WAVE OVER SOUTHERN CANADA MOVES OUT OF THE PLAINS. IN THE WAKE
OF THE EXITING TROF...COOLER TEMPS AND NORTHERLY WINDS ARE
EXPECTED ACROSS THE REGION INTO THE START OF THE NEXT WORK WEEK.
SOUTHERLY WINDS QUICKLY RETURN WITH WARMER TEMPERATURES AGAIN FOR
THE MIDDLE PART OF NEXT WEEK AHEAD OF A LONGWAVE TROF FORECAST
TO MOVE OUT OF SOUTHERN CANADA INTO THE PLAINS. LATEST GFS AND
ECMWF DISAGREE ON TIMING OF THIS NEXT WAVE AND ASSOCIATED COLD
FRONT INTO THE CWA. THE ECMWF IS ABOUT 12-24 HRS FASTER COMPARED
TO THE GFS. WILL USE A BLENDED MODEL SOLUTION ALONG WITH PREVIOUS
FORECAST...PUSHING THE FRONT THROUGH WEDNESDAY NIGHT AND THURSDAY.
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL AGAIN BECOME POSSIBLE
MID WEEK AND CONTINUE INTO THE SECOND HALF OF NEXT WEEK AS THE
FRONT MOVES THROUGH. COOLER TEMPS WILL AGAIN BE POSSIBLE LATE NEXT
WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 77 97 75 94 / 0 0 10 30
FSM 74 95 73 95 / 0 10 10 10
MLC 75 95 74 94 / 0 0 0 10
BVO 73 96 69 92 / 0 10 10 40
FYV 69 91 67 92 / 10 10 10 30
BYV 70 93 69 92 / 10 10 10 30
MKO 74 95 73 94 / 0 10 10 30
MIO 73 95 71 91 / 0 10 10 40
F10 75 95 74 94 / 0 0 10 30
HHW 74 95 73 95 / 0 0 0 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...30
LONG TERM....20
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
500 PM CDT WED SEP 3 2014
.MESOSCALE DISCUSSION...
ISSUED AT 500 PM CDT WED SEP 3 2014
CONVECTIVE EVOLUTION FOR TONIGHT REMAINS UNCERTAIN...SO PLAN ON
PROVIDING MESOSCALE DISCUSSION UPDATES THROUGHOUT THE EVENING.
ONGOING SHOWERS AND THUNDERSTORMS FROM NORTH OF ST CLOUD INTO
NORTHERN WI EXIST ON THE NOSE OF 925-850MB MOISTURE TRANSPORT...AS
WELL AS NORTH OF A WARM FRONTAL BOUNDARY SITUATED ALONG I-94.
THESE HAVE CONTINUED TO MOVE NORTHEAST THROUGH THE DAY AS A RESULT
OF PERSISTENT SOUTHERLY FLOW...AS SEEN ON KMPX VAD WIND PROFILE.
WATER VAPOR FOR THE MOST PART IS VERY NON-DESCRIPT IN TERMS OF
EASILY IDENTIFIABLE SHORTWAVES FROM THE DAKOTAS INTO OUR REGION.
THERE COULD BE ONE NEAR ABERDEEN SD AND ANOTHER NEAR OMAHA...BOTH
MOVING NORTHEAST...BUT THATS IT.
CLOSELY MONITORING TO SEE IF CONVECTION CAN DEVELOP OVER WEST-
CENTRAL MN OVER THE NEXT FEW HOURS. IF IT DOES AND CAN EVOLVE INTO
AN MCS...WHICH WOULD SEEM LIKELY GIVEN STRENGTHENING 850MB
MOISTURE TRANSPORT THROUGH THE EVENING AND PLENTIFUL
CAPE...CORFIDI VECTORS WOULD BRING IT INTO THE AREA.
OTHERWISE...SEEMS THE MAIN FOCUS FOR THE EVENING IS WATCHING THE
STRONGER CONVECTION NORTH OF ST CLOUD AND IF IT CAN MATURE INTO AN
MCS...CAUSING IT TO ROLL THROUGH LOCATIONS MAINLY ALONG/NORTH OF
I-94 LATE IN THE EVENING.
HEADING INTO THE OVERNIGHT...THE 03.20Z/21Z RAP...03.19Z/20Z HRRR
AND THE 03.18Z NAM-NEST ALL POP UP CONVECTION OVER NORTHEAST IOWA
AND SOUTHWEST WI BETWEEN MIDNIGHT AND 2 AM. THIS IS ON THE NOSE
OF A SECOND 850MB MOISTURE TRANSPORT MAXIMA COMING UP THROUGH
IOWA...LIKELY INDUCED BY THE NORMAL NOCTURNAL INCREASE AND THE TWO
SHORTWAVES APPROACHING THE AREA FROM THE WEST. WILL KEEP AN EYE ON
THIS SCENARIO THROUGH THE EVENING. SHOULD THIS SCENARIO
OCCUR...RAP SOUNDINGS SUGGEST VERY HEAVY RAIN THAT COULD RESULT IN
FLASH FLOODING AND MARGINALLY SEVERE HAIL WOULD BE THE MAIN
HAZARDS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 350 PM CDT WED SEP 3 2014
AT 3 PM...A WARM FRONT EXTENDED FROM WOODLAKE MINNESOTA SOUTHEAST
TO FAIRFIELD IOWA /SOUTHEAST CORNER OF THE STATE/. DEW POINTS
SOUTH OF THIS FRONT WERE IN THE LOWER 70S. MEANWHILE NORTH OF THIS
FRONT DEW POINTS RANGED FROM MID 50S TO MID 60S. THE LOWEST DEW
POINTS WERE FOUND ACROSS CENTRAL WISCONSIN. THERE IS NO WEATHER
CURRENTLY ASSOCIATED WITH THIS FRONT. MEANWHILE FURTHER NORTH...A
GENERALLY WEST TO EAST BAND OF PRECIPITATION WAS LOCATED FROM
ALEXANDRIA MINNESOTA TO MERRILL WISCONSIN. THIS BAND WAS
DEVELOPING IN AN AREA OF 850 TO 700 MB FRONTOGENESIS FORCING AND
MOISTURE TRANSPORT. IN ADDITION...THERE IS A SHORT WAVE TROUGH
MOVING THROUGH NORTHERN MINNESOTA. THE LATEST RAP SUGGESTS THAT
THIS WAVE WILL TAKE THE BEST 850 TO 700 MB MOISTURE TRANSPORT
NORTH NORTHEAST TOWARD UPPER MICHIGAN THIS EVENING. MOST OF THE
MESO MODELS SUGGEST THAT THIS BAND OF PRECIPITATION WILL REMAIN
ACROSS CENTRAL MINNESOTA AND NORTHERN WISCONSIN THIS EVENING. THIS
BAND MAY POSSIBLY IMPACT TAYLOR AND CLARK COUNTIES IN NORTH-
CENTRAL WISCONSIN. THERE IS SUFFICIENT 0-6KM SHEAR FOR SUPERCELL
DEVELOPMENT INITIALLY AND THIS EVOLVES INTO A LINE AS THE COLD
POOL DEVELOPS. THE MAIN SEVERE WEATHER THREATS WOULD BE DAMAGING
WINDS AND POSSIBLY LARGE HAIL BETWEEN 04.02Z AND 04.06Z. IN
ADDITION WITH WARM CLOUD LAYERS DEPTHS AROUND 4 KM AND
PRECIPITABLE WATER AROUND 1.5 INCHES...THE STORMS WILL BE
EFFICIENT RAIN PRODUCERS. WE WILL HAVE TO WATCH CLOSELY FOR
TRAINING CELLS.
FOR THE OVERNIGHT...THERE IS QUITE A BIT OF UNCERTAINTY ON HOW
THINGS WILL EVOLVE. THE LATEST RAP SUGGESTS THAT ANOTHER WING OF
STRONG 850 MB TO 700 MB MOISTURE TRANSPORT DEVELOPS OVER NORTHEAST
IOWA AS ANOTHER SHORT WAVE /CURRENTLY OVER SOUTH DAKOTA/ MOVES
INTO THE AREA. THIS WOULD SUGGEST THE POSSIBILITY THAT ANOTHER
AREA OF SHOWERS AND STORMS WILL DEVELOP ACROSS EAST-CENTRAL
MINNESOTA AND WEST-CENTRAL WISCONSIN. LIKE ITS PREDECESSOR...THE
STORMS WOULD INITIALLY FORM AS SUPERCELLS AND THEN EVOLVE INTO
ANOTHER LINE OR LINES OF STORMS WOULD DROP SOUTH ALONG AND NORTH
ACROSS WESTERN WISCONSIN WITH A MAJORITY OF THE ACTIVITY ALONG AND
NORTH OF THE INTERSTATE 94 CORRIDOR. THIS IS ACTUALLY IN DECENT
AGREEMENT WITH WHAT THE 03.12Z NAM...ARW...AND NMM IS SHOWING IN
THEIR DETERMINISTIC SOLUTIONS. THE MAIN THREAT WOULD BE HAIL
INITIALLY AND THEN QUICKLY EVOLVE INTO A WIND THREAT AS THEY
FOLLOW THE CORFIDI VECTORS TO THE SOUTHEAST INTO THE HIGHER CAPES.
ANOTHER SCENARIO SHOWS UP IN THE SPC WRF WHERE IT TAKES THE
CURRENT LINE OF CONVECTION AND DIVES THIS SOUTH THROUGH OUR
FORECAST AREA. OVERALL PREFER THE LATTER SOLUTION...SO TRENDED THE
FORECAST TOWARD IT.
ON THURSDAY...A STRONG CAP DEVELOPS ACROSS THE AREA. 700 MB
TEMPERATURES IN THIS CAP CLIMB TO 14C. THIS IS THE STRONGEST CAP
OF THE YEAR FOR OUR AREA. BOTH THE GFS AND ECMWF SUGGEST THAT THIS
CAP WILL KEEP MOST OF THE AREA DRY FOR THIS TIME PERIOD. MEANWHILE
THE NAM SHOWS THAT A SHORT WAVE...CURRENTLY OVER COLORADO...WILL
MOVE THROUGH NORTH CENTRAL WISCONSIN DURING THE AFTERNOON. THE
LIFT ASSOCIATED WITH THIS WAVE CAUSE THIS CAP TO COOL INTO THE 8C
TO 10C RANGE. WITH MOST UNSTABLE CAPES IN THE 2 TO 4K
RANGE...THUNDERSTORMS WOULD RAPIDLY DEVELOP. THE 0-6 KM SHEAR
WOULD BE SUFFICIENT FOR SUPERCELLS INITIALLY...AND THEN QUICKLY
EVOLVE INTO A LINE AS THE 0-3KM SHEAR TAKES OVER. CONFIDENCE IN
THIS SCENARIO WAS NOT EXCEPTIONALLY HIGH...SO KEPT PRECIPITATION
CHANCES IN THE 20 TO 50 PERCENT RANGE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 PM CDT WED SEP 3 2014
ON THURSDAY NIGHT...THE 03.12Z MODELS CONTINUE TO SHOW THAT A
STRONG CANADIAN COLD FRONT WILL MOVE EAST THROUGH THE FORECAST
AREA. THIS FRONT WILL BE MOVING EAST INTO 3 TO 5K MOST UNSTABLE
CAPES. THE BEST LIFT WITH THIS WAVE IS FURTHER NORTH...SO IT IS
GOING TO TAKE SOME TIME TO COOL THE CAP. SO THERE ARE SOME
QUESTIONS ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA ON HOW
WIDESPREAD AND HOW FAST THE STORMS WILL DEVELOP. WHILE THE 0-6KM
SHEAR IS NOT AS STRONG AS IT WILL BE TONIGHT AND ON THURSDAY...
THE 0-3 KM SHEAR WILL BE SUFFICIENT FOR SOME DAMAGING WINDS. IN
ADDITION...THE STRONG CAPES MAY ALSO AID IN THE DEVELOPMENT OF
LARGE HAIL.
ON SATURDAY NIGHT...ANOTHER SHORT WAVE TROUGH WILL MOVE THROUGH
THE AREA. WITH THE AIRMASS RATHER DRY...EXPECT THAT THIS SYSTEM
WILL JUST BRING ANOTHER REINFORCING SHOT OF COOL AIR.
FROM MONDAY NIGHT INTO TUESDAY...A LONG WAVE TROUGH WILL MOVE
THROUGH THE REGION. WHILE THE GFS HAS THIS SYSTEM NEGATIVELY
TILTED...THE BEST 0-6 KM STAYS TO OUR SOUTH. IN ADDITION...THE
TIMING OF THIS WAVE IS NOT THAT FAVORABLE FOR THAT MUCH
INSTABILITY ACROSS OUR AREA. AS A RESULT...NOT EXPECTING ANY
SEVERE WEATHER AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1245 PM CDT WED SEP 3 2014
GUSTY SOUTH WINDS ARE EXPECTED AT THE TAF SITES TODAY AS A WARM
FRONT LIFTS THROUGH THE REGION...WITH SOUTH WINDS OF 13 TO 16 KTS
WITH GUSTS AROUND 25 KTS POSSIBLE. LOOK FOR SCT TO BKN CUMULUS
THIS AFTERNOON WITH CLOUD BASES IN THE 2-4KFT RANGE. SHOWERS AND
STORMS ARE EXPECTED TO DEVELOP NORTH OF THE TAF SITES LATE THIS
AFTERNOON AND EARLY EVENING...CLOSER TO THE INTERSTATE 94
CORRIDOR NEAR THE TWIN CITIES. THESE STORMS ARE THEN EXPECTED TO
TRACK EAST/SOUTHEAST INTO PORTION OF WESTERN AND NORTHERN
WISCONSIN. AT THIS TIME THE STORMS LOOK TO STAY NORTH OF THE TAF
SITES BUT IF THEY TAKE A HARD SOUTHEAST TURN...THEY COULD IMPACT
KLSE AND POSSIBLY KRST. IF THEY WOULD MAKE IT TO THE TAF
SITES...STRONG AND GUSTY WINDS WOULD BE A POSSIBILITY. WILL HAVE
TO KEEP A VERY CLOSE EYE ON THE EVOLUTION OF THE STORMS LATE THIS
AFTERNOON INTO THIS EVENING. ANOTHER CONCERN TONIGHT WILL BE LOW
LEVEL WIND SHEAR WITH A STRONG LOW LEVEL JET SETTING UP THIS
EVENING AND PERSISTING INTO THE OVERNIGHT HOURS. PLAN ON WINDS
INCREASING TO 50 KTS AT 2KFT. THE LOW LEVEL JET WILL SUBSIDE AFTER
14Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
MESOSCALE...AJ
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
352 PM CDT WED SEP 3 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 350 PM CDT WED SEP 3 2014
AT 3 PM...A WARM FRONT EXTENDED FROM WOODLAKE MINNESOTA SOUTHEAST
TO FAIRFIELD IOWA /SOUTHEAST CORNER OF THE STATE/. DEW POINTS
SOUTH OF THIS FRONT WERE IN THE LOWER 70S. MEANWHILE NORTH OF THIS
FRONT DEW POINTS RANGED FROM MID 50S TO MID 60S. THE LOWEST DEW
POINTS WERE FOUND ACROSS CENTRAL WISCONSIN. THERE IS NO WEATHER
CURRENTLY ASSOCIATED WITH THIS FRONT. MEANWHILE FURTHER NORTH...A
GENERALLY WEST TO EAST BAND OF PRECIPITATION WAS LOCATED FROM
ALEXANDRIA MINNESOTA TO MERRILL WISCONSIN. THIS BAND WAS
DEVELOPING IN AN AREA OF 850 TO 700 MB FRONTOGENESIS FORCING AND
MOISTURE TRANSPORT. IN ADDITION...THERE IS A SHORT WAVE TROUGH
MOVING THROUGH NORTHERN MINNESOTA. THE LATEST RAP SUGGESTS THAT
THIS WAVE WILL TAKE THE BEST 850 TO 700 MB MOISTURE TRANSPORT
NORTH NORTHEAST TOWARD UPPER MICHIGAN THIS EVENING. MOST OF THE
MESO MODELS SUGGEST THAT THIS BAND OF PRECIPITATION WILL REMAIN
ACROSS CENTRAL MINNESOTA AND NORTHERN WISCONSIN THIS EVENING. THIS
BAND MAY POSSIBLY IMPACT TAYLOR AND CLARK COUNTIES IN NORTH-
CENTRAL WISCONSIN. THERE IS SUFFICIENT 0-6KM SHEAR FOR SUPERCELL
DEVELOPMENT INITIALLY AND THIS EVOLVES INTO A LINE AS THE COLD
POOL DEVELOPS. THE MAIN SEVERE WEATHER THREATS WOULD BE DAMAGING
WINDS AND POSSIBLY LARGE HAIL BETWEEN 04.02Z AND 04.06Z. IN
ADDITION WITH WARM CLOUD LAYERS DEPTHS AROUND 4 KM AND
PRECIPITABLE WATER AROUND 1.5 INCHES...THE STORMS WILL BE
EFFICIENT RAIN PRODUCERS. WE WILL HAVE TO WATCH CLOSELY FOR
TRAINING CELLS.
FOR THE OVERNIGHT...THERE IS QUITE A BIT OF UNCERTAINTY ON HOW
THINGS WILL EVOLVE. THE LATEST RAP SUGGESTS THAT ANOTHER WING OF
STRONG 850 MB TO 700 MB MOISTURE TRANSPORT DEVELOPS OVER NORTHEAST
IOWA AS ANOTHER SHORT WAVE /CURRENTLY OVER SOUTH DAKOTA/ MOVES
INTO THE AREA. THIS WOULD SUGGEST THE POSSIBILITY THAT ANOTHER
AREA OF SHOWERS AND STORMS WILL DEVELOP ACROSS EAST-CENTRAL
MINNESOTA AND WEST-CENTRAL WISCONSIN. LIKE ITS PREDECESSOR...THE
STORMS WOULD INITIALLY FORM AS SUPERCELLS AND THEN EVOLVE INTO
ANOTHER LINE OR LINES OF STORMS WOULD DROP SOUTH ALONG AND NORTH
ACROSS WESTERN WISCONSIN WITH A MAJORITY OF THE ACTIVITY ALONG AND
NORTH OF THE INTERSTATE 94 CORRIDOR. THIS IS ACTUALLY IN DECENT
AGREEMENT WITH WHAT THE 03.12Z NAM...ARW...AND NMM IS SHOWING IN
THEIR DETERMINISTIC SOLUTIONS. THE MAIN THREAT WOULD BE HAIL
INITIALLY AND THEN QUICKLY EVOLVE INTO A WIND THREAT AS THEY
FOLLOW THE CORFIDI VECTORS TO THE SOUTHEAST INTO THE HIGHER CAPES.
ANOTHER SCENARIO SHOWS UP IN THE SPC WRF WHERE IT TAKES THE
CURRENT LINE OF CONVECTION AND DIVES THIS SOUTH THROUGH OUR
FORECAST AREA. OVERALL PREFER THE LATTER SOLUTION...SO TRENDED THE
FORECAST TOWARD IT.
ON THURSDAY...A STRONG CAP DEVELOPS ACROSS THE AREA. 700 MB
TEMPERATURES IN THIS CAP CLIMB TO 14C. THIS IS THE STRONGEST CAP
OF THE YEAR FOR OUR AREA. BOTH THE GFS AND ECMWF SUGGEST THAT THIS
CAP WILL KEEP MOST OF THE AREA DRY FOR THIS TIME PERIOD. MEANWHILE
THE NAM SHOWS THAT A SHORT WAVE...CURRENTLY OVER COLORADO...WILL
MOVE THROUGH NORTH CENTRAL WISCONSIN DURING THE AFTERNOON. THE
LIFT ASSOCIATED WITH THIS WAVE CAUSE THIS CAP TO COOL INTO THE 8C
TO 10C RANGE. WITH MOST UNSTABLE CAPES IN THE 2 TO 4K
RANGE...THUNDERSTORMS WOULD RAPIDLY DEVELOP. THE 0-6 KM SHEAR
WOULD BE SUFFICIENT FOR SUPERCELLS INITIALLY...AND THEN QUICKLY
EVOLVE INTO A LINE AS THE 0-3KM SHEAR TAKES OVER. CONFIDENCE IN
THIS SCENARIO WAS NOT EXCEPTIONALLY HIGH...SO KEPT PRECIPITATION
CHANCES IN THE 20 TO 50 PERCENT RANGE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 PM CDT WED SEP 3 2014
ON THURSDAY NIGHT...THE 03.12Z MODELS CONTINUE TO SHOW THAT A
STRONG CANADIAN COLD FRONT WILL MOVE EAST THROUGH THE FORECAST
AREA. THIS FRONT WILL BE MOVING EAST INTO 3 TO 5K MOST UNSTABLE
CAPES. THE BEST LIFT WITH THIS WAVE IS FURTHER NORTH...SO IT IS
GOING TO TAKE SOME TIME TO COOL THE CAP. SO THERE ARE SOME
QUESTIONS ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA ON HOW
WIDESPREAD AND HOW FAST THE STORMS WILL DEVELOP. WHILE THE 0-6KM
SHEAR IS NOT AS STRONG AS IT WILL BE TONIGHT AND ON THURSDAY...
THE 0-3 KM SHEAR WILL BE SUFFICIENT FOR SOME DAMAGING WINDS. IN
ADDITION...THE STRONG CAPES MAY ALSO AID IN THE DEVELOPMENT OF
LARGE HAIL.
ON SATURDAY NIGHT...ANOTHER SHORT WAVE TROUGH WILL MOVE THROUGH
THE AREA. WITH THE AIRMASS RATHER DRY...EXPECT THAT THIS SYSTEM
WILL JUST BRING ANOTHER REINFORCING SHOT OF COOL AIR.
FROM MONDAY NIGHT INTO TUESDAY...A LONG WAVE TROUGH WILL MOVE
THROUGH THE REGION. WHILE THE GFS HAS THIS SYSTEM NEGATIVELY
TILTED...THE BEST 0-6 KM STAYS TO OUR SOUTH. IN ADDITION...THE
TIMING OF THIS WAVE IS NOT THAT FAVORABLE FOR THAT MUCH
INSTABILITY ACROSS OUR AREA. AS A RESULT...NOT EXPECTING ANY
SEVERE WEATHER AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1245 PM CDT WED SEP 3 2014
GUSTY SOUTH WINDS ARE EXPECTED AT THE TAF SITES TODAY AS A WARM
FRONT LIFTS THROUGH THE REGION...WITH SOUTH WINDS OF 13 TO 16 KTS
WITH GUSTS AROUND 25 KTS POSSIBLE. LOOK FOR SCT TO BKN CUMULUS
THIS AFTERNOON WITH CLOUD BASES IN THE 2-4KFT RANGE. SHOWERS AND
STORMS ARE EXPECTED TO DEVELOP NORTH OF THE TAF SITES LATE THIS
AFTERNOON AND EARLY EVENING...CLOSER TO THE INTERSTATE 94
CORRIDOR NEAR THE TWIN CITIES. THESE STORMS ARE THEN EXPECTED TO
TRACK EAST/SOUTHEAST INTO PORTION OF WESTERN AND NORTHERN
WISCONSIN. AT THIS TIME THE STORMS LOOK TO STAY NORTH OF THE TAF
SITES BUT IF THEY TAKE A HARD SOUTHEAST TURN...THEY COULD IMPACT
KLSE AND POSSIBLY KRST. IF THEY WOULD MAKE IT TO THE TAF
SITES...STRONG AND GUSTY WINDS WOULD BE A POSSIBILITY. WILL HAVE
TO KEEP A VERY CLOSE EYE ON THE EVOLUTION OF THE STORMS LATE THIS
AFTERNOON INTO THIS EVENING. ANOTHER CONCERN TONIGHT WILL BE LOW
LEVEL WIND SHEAR WITH A STRONG LOW LEVEL JET SETTING UP THIS
EVENING AND PERSISTING INTO THE OVERNIGHT HOURS. PLAN ON WINDS
INCREASING TO 50 KTS AT 2KFT. THE LOW LEVEL JET WILL SUBSIDE AFTER
14Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1108 AM CDT WED SEP 3 2014
.UPDATE...FOR SEVERE WEATHER POTENTIAL TONIGHT
ISSUED AT 1108 AM CDT WED SEP 3 2014
THE SEVERE WEATHER THREAT REMAINS ON TRACK FOR TONIGHT. SEVERE
THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE THIS AFTERNOON INTO
EARLY THIS EVENING OVER PORTIONS OF CENTRAL MINNESOTA THEN TRACK
EAST INTO WISCONSIN THROUGH THE EVENING HOURS. CONFIDENCE IS THE
HIGHEST ON AREAS ALONG AND NORTH OF INTERSTATE 94 SEEING THIS
ACTIVITY. DAMAGING WINDS...LARGE HAIL...AND HEAVY RAINFALL APPEAR
THE BE THE MAIN HAZARDS. CANNOT RULE OUT AN ISOLATED TORNADO IF
THE STORMS WOULD MOVE IN DURING THE EARLY TO MID EVENING HOURS.
MESOSCALE MODELS CONTINUE TO SHOW THE BULK OF THE ACTIVITY
IMPACTING LOCATIONS NORTH OF INTERSTATE 94...IMPACTING MAINLY
CLARK AND TAYLOR COUNTIES. HOWEVER...THE 12Z NAM AND 00Z ECMWF
CONTINUE TO BRING AN MCS SOUTHEAST INTO THE FORECAST AREA FROM
THE TWIN CITIES AREA AROUND MID EVENING. IF THIS TRACK
HOLDS...LOCATIONS NORTH OF INTERSTATE 90 WOULD BE IMPACTED. WILL
HAVE TO KEEP AN EYE ON HEAVY RAIN POTENTIAL TONIGHT AS WELL WITH
PRECIPITABLE WATER VALUES INCREASING INTO THE 1.8 TO 2.0 INCH
RANGE AND WARM CLOUD DEPTHS CLIMBING TO 4.0 KM.
MOISTURE CONTINUES TO STREAM NORTHWARD THROUGH IOWA LATE THIS
MORNING WITH DEW POINTS CLIMBING INTO 70S. SO MOISTURE IS
STREAMING NORTHWARD AND WILL FUEL SEVERE THUNDERSTORM DEVELOPMENT
LATE THIS AFTERNOON INTO THIS EVENING. ONGOING STORMS THIS
MORNING OVER CENTRAL MINNESOTA SHOULD DISSIPATE AND CONTINUE TO
SHIFT NORTH INTO EARLY THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 338 AM CDT WED SEP 3 2014
MAIN CONCERN FOCUSED ON SEVERE POTENTIAL TONIGHT AND AGAIN THURSDAY
NIGHT.
WATER VAPOR OR BIG PICTURE VIEW SHOWS A FAIRLY HIGH ZONAL FLOW
ACROSS THE NORTHERN CONUS. A WEAK EMBEDDED MID-LEVEL TROUGH WAS
NOTED EJECTING NORTHEAST OUT OF WY INTO WESTERN SD. AT THE
SURFACE...A WARM FRONT EXTENDED FROM SOUTHWEST SD INTO EASTERN NEB.
LIFT AHEAD OF THE WAVE AND WARM FRONT WAS PRODUCING A SMALL AREA OF
SHOWERS/THUNDERSTORMS OVER EASTERN SD/FAR SOUTHWEST MN PER LATEST
REGIONAL RADAR MOSAIC. OTHERWISE...CLOSER TO HOME...HIGH PRESSURE WAS
PRODUCING MOSTLY CLEAR SKIES ACROSS THE FORECAST AREA WITH
TEMPERATURES RANGING FROM THE LOWER 50S A NEAR 60 DEGREES.
FOR TODAY...SURFACE CYCLOGENESIS WILL CONTINUE TO TAKE SHAPE OVER
MT/NORTHERN PLAINS. THIS WILL LIFT THE AFOREMENTIONED WARM FRONT OUT
OF THE CENTRAL PLAINS INTO SOUTHERN MN. ALSO...STRENGTHENING
SOUTHERLY FLOW WILL PRODUCE INCREASING MOISTURE TRANSPORT/ISENTROPIC
LIFT INTO THE AREA. THIS IS EXPECTED TO FUEL ELEVATED AND SCATTERED
SHOWERS/THUNDERSTORMS MAINLY ALONG AND NORTH OF I-90 THROUGH THE
DAY. PLAN ON HIGHS IN THE 75-85 DEGREE RANGE.
AS WE GO INTO TONIGHT...STRENGTHENING LOW PRESSURE MOVING FROM THE
DAKOTAS INTO WESTERN MN WILL DRIVE THE WARM FRONT FARTHER
NORTHEAST...NEAR THE I-94 CORRIDOR BY MORNING. THIS IS WHERE IT GETS
COMPLICATED. 850MB MOISTURE TRANSPORTS CRANKS UP SIGNIFICANTLY WITH
VECTORS POINTED DIRECTLY INTO THE AREA. AT THE SAME TIME...STRONG
CAP SETS UP ALONG THE MISSISSIPPI RIVER AS EVIDENCED BY THE NAM/GFS
BUFKIT SOUNDINGS. EXPECTING A COMPLEX OF THUNDERSTORMS TO FIRE
SOMEWHERE ALONG I-94 BETWEEN THE TWIN CITIES AND SAINT CLOUD MN BY
THIS EVENING ON THE EDGE OF THIS CAP AND ON THE NOSE OF THE MOISTURE
TRANSPORT. FORWARD PROPAGATING CORFIDI VECTORS BRING THIS COMPLEX
SOUTHEAST AND THEN ON A MORE SOUTHERLY TRAJECTORY ONCE IT GETS EAST
OF THE MISSISSIPPI...AGAIN ON THE EDGE OF THE CAP AND IN THE
CORRIDOR OF VERY RICH MOISTURE FEED.
THIS COMPLEX WILL HAVE TO BE WATCHED CLOSELY FOR SEVERE THREAT.
EARLY ON IN THE EVENING...MODEL CONSENSUS 0-3KM MUCAPE OF 2500-
4000J/KG AND 0-6KM BULK SHEAR OF 40-50KT WILL BE SUFFICIENT FOR
SUPERCELL DEVELOPMENT MAINLY ACROSS EAST CENTRAL MN INTO NORTHWEST
WI FOR LARGE HAIL POTENTIAL...AND TORNADO THREAT IF STORMS GET
ROOTED IN THE BOUNDARY LAYER. AS MENTIONED...THEN EXPECTING THIS
THUNDERSTORM COMPLEX TO FOLLOW CORFIDI VECTORS...TAKING INTO DIRECTLY
OVER OUR AREA MAINLY EAST OF THE MISSISSIPPI RIVER TONIGHT. BY THEN
MOST OF THESE STORMS WILL BE ELEVATED IN NATURE. WITH PRECIPITABLE
WATER VALUES OF 1.5-2 INCHES OFF THE NAM AND GFS...HEAVY RAINFALL
BECOMES THE MAIN THREAT ALONG WITH DAMAGING WIND POTENTIAL. SOME
LARGE HAIL WILL ALSO BE POSSIBLE. CANNOT RULE OUT THE POSSIBILITY OF
SOME FLASH FLOODING IF THERE IS ANY REPETITIVE CONVECTION OVER NAY
ONE AREA...BUT SYSTEM SEEMS OVERALL PRETTY PROGRESSIVE IN NATURE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 338 AM CDT WED SEP 3 2014
MODELS SHOW DEEP AREA OF LOW PRESSURE MOVING NORTH OUT OF WESTERN MN
INTO WESTERN ONTARIO BY LATE AFTERNOON. AS A RESULT...WARM FRONT WILL
PUSH NORTHEAST THROUGH THE AREA WITH A VERY WARM/HUMID/CAPPED DAY IN
STORE. HIGH TEMPERATURES ARE EXPECTED TO PUSH INTO THE 85-91 DEGREE
RANGE WITH DEW POINTS IN THE LOWER 70S. THIS WILL RESULT IN HEAT
INDICES OF 90-100.
AS THE LOW CONTINUES TO LIFT NORTHEAST INTO ONTARIO A COLD FRONT
WILL THEN PUSH THROUGH THE AREA THURSDAY NIGHT. INITIALLY THE AREA
REMAINS UNDER THE INFLUENCE OF THE STRONG CAP...BUT CONVECTION IS
EXPECTED TO EVENTUALLY FIRE IN THE EVENING AFTER 6 PM...AS THE
FRONT/ALONG WITH MID-LEVEL TROUGH MOVES IN WITH COOLING
ALOFT...WHICH SHOULD THEN BE ENOUGH TO OVERCOME THE CAP. SOME OF
THESE STORMS SHOULD BE COME SEVERE WITH DAMAGING WIND AND LARGE HAIL
BEING THE MAIN THREATS.
FOR FRIDAY INTO THE WEEKEND...
DRIER/COOLER AIR MOVES INTO THE AREA FRIDAY BEHIND THE FRONT. LOOK
FOR HIGHS IN THE UPPER 60S TO THE MIDDLE 70S.
COOL AND DRY CONDITIONS LOOK TO PERSIST THROUGH THE WEEKEND AS
CANADIAN HIGH PRESSURE DOMINATES THE MID-SECTION OF THE CONUS/UPPER
MISSISSIPPI RIVER VALLEY REGIONS. HIGHS SATURDAY AND SUNDAY STAY IN
THE UPPER 60S/LOWER 70S WITH OVERNIGHT LOWS DIPPING INTO THE 40S AND
LOWER 50S.
FOR MONDAY INTO TUESDAY...
HIGH PRESSURE DRIFTS OFF TO THE EAST AS LOW PRESSURE APPROACHES FROM
THE PLAINS. AS A RESULT...PLAN ON SHOWER/THUNDERSTORM CHANCES TO
INCREASE THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 617 AM CDT WED SEP 3 2014
AREA OF ELEVATED SHOWERS AND STORMS OVER SOUTHWEST MINNESOTA IN
ASSOCIATION WITH A WEAK SHORT WAVE TROUGH. THE 03.09Z RAP SUGGESTS
THE WAVE WILL CONTINUE TO MOVE EAST TOWARD THE AREA WHILE THE MID
LEVEL MOISTURE TRANSPORT LIFTS NORTHEAST. THE 03.00Z HI-RES ARW
AND 03.09Z HRRR BOTH SUGGEST THE ACTIVITY WILL LIFT NORTHEAST WITH
THE MOISTURE TRANSPORT AND MISS BOTH TAF SITES. FEEL THE BULK OF
THE ACTIVITY SHOULD MISS THE TAF SITES BUT WILL CARRY A VCTS AT
KRST IN THE EVENT THAT THE MOVEMENT ENDS UP BEING MORE TO THE
EAST. AFTER THAT...WARM AIR ALOFT WILL RAPIDLY BUILD OVER THE AREA
TODAY PUTTING A CAP IN PLACE THAT SHOULD ALLOW THE NEXT ROUND OF
CONVECTION TO FORM NORTH OF BOTH TAF SITES LATE THIS AFTERNOON
INTO THE EVENING. ALL THE MESO MODELS SUGGEST THE ACTIVITY WILL
THEN STAY NORTH OF THE AREA THROUGH THE OVERNIGHT...BUT THE 03.00Z
ECMWF SUGGEST SOME SOUTHEAST MOVEMENT ALONG THE EDGE OF THE CAP
CLOSE TO THE BACKWARD PROPAGATING CORFIDI VECTORS. IF THIS CAN
OCCUR...THERE IS A CHANCE SOME ACTIVITY COULD MOVE DOWN THE
MISSISSIPPI RIVER INTO WESTERN WISCONSIN AND WILL CONTINUE TO
CARRY A VCTS IN THE LATE EVENING FOR THIS AT KLSE BUT THINK IT
WILL MISS KRST...IF IT CAN TURN SOUTHEAST. WITH THE STRONG LOW
LEVEL JET FEEDING INTO THE CONVECTIVE ACTIVITY...LOW LEVEL WIND
SHEAR SHOULD BE PRESENT AND HAVE INCLUDED THIS OUTSIDE OF THE
THUNDER TIME IN THE EVENING AND OVERNIGHT HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...WETENKAMP
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04