Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/06/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
826 PM MST MON AUG 5 2013
.SYNOPSIS...SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS
WILL CONTINUE THROUGH THE EARLY PORTION OF THE WEEK...THEN A BIT
DRIER WITH ISOLATED TO SCATTERED THUNDERSTORMS FROM THE MIDDLE OF
THE WEEK INTO NEXT WEEKEND.
&&
.DISCUSSION...STORMS THIS EVENING ARE HEAVY RAIN PRODUCERS WITH SOME
AREAS RECEIVING OVER AN INCH IN TWENTY MINUTES. THEY ARE HOWEVER
MOVING FAST ENOUGH TO AVOID ANY MAJOR FLOODING CONCERNS. THERE IS
SOME CONCERN STILL WITH REDUCED VISIBILITY...PONDING ON ROADWAYS
AND LOCALIZED FLOODING ASSOCIATED WITH THESE STORMS. CARE SHOULD
SHOULD ALSO BE TAKEN AS WASHES WILL BE FLOWING.
STORMS ARE CONTINUING TO FIRE UP ALONG AN OUTFLOW BOUNDARY MOVING
WEST OUT OF COCHISE COUNTY...THIS OUTFLOW HAS THE POTENTIAL TO MAKE
IT INTO THE TUCSON METRO AREA TONIGHT. THERE IS ALSO A CHANCE FOR
SOME CONTINUED OVERNIGHT ACTIVITY AS AN UPPER LEVEL VORTICITY MAX
MOVES FROM NORTHERN MEXICO INTO THE AREA. THE SYSTEM WILL CONTINUE
INTO THE NORTHERN PART OF THE STATE BY LATE TOMORROW. FORCING FROM
THIS SYSTEM SHOULD RESULT IN SCATTERED STORM DEVELOPMENT OVER MOST
OF THE DESERT/VALLEY LOCATIONS AND SLIGHTLY BETTER CHANCES FOR THE
HIGHER TERRAIN TOMORROW.
FOR EXTENDED FORECAST SEE PREVIOUS DISCUSSION.
&&
.AVIATION...SCT SHRA/TSRA ACTIVITY PERSISTING OVERNIGHT THROUGH
06/15Z...THEN SCT TSRA DEVELOPING AFT 06/23Z AND CONTINUING THRU
07/05Z...WIND GUSTS TO 45 KTS NEAR ANY TSRA...AS WELL AS LOCAL
MVFR/IFR CIGS/VSBYS. OTHERWISE...SURFACE WIND GENERALLY LESS THAN 10
KTS THRU 07/18Z. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...MOISTURE WILL REMAIN IN PLACE ACROSS THE REGION
THROUGH THE FIRST PART OF THIS WEEK...RESULTING IN A CHANCE OF
MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ACROSS
SOUTHEAST ARIZONA. SLIGHTLY DRIER AIR WILL MOVE IN FROM THE WEST
DURING THE LATTER PART OF THE WEEK AND INTO THE WEEKEND FOR SLIGHTLY
LESSER RAIN CHANCES. OUTSIDE OF GUSTY THUNDERSTORM OUTFLOWS...WINDS
DURING THE PERIOD ARE EXPECTED TO BE LIGHT...GENERALLY LESS THAN 15
MPH AND DIURNALLY DRIVEN.
&&
.PREV DISCUSSION...VISIBLE IMAGERY SHOWS A DOUBLE VORTEX MCV FROM
THE DECAYING COMPLEX LAST NIGHT AND EARLY THIS MORNING IS NOW NEAR
SHOW LOW. MEANWHILE...ANOTHER MCV IS OVER WEST CENTRAL
SONORA...RIGHT ALONG THE COAST. EXTENSIVE MID LEVEL CLOUDINESS
ASSOCIATED WITH THIS SYSTEM EXTENDS NORTHWARD ACROSS NORTHWEST
SONORA AND INTO SOUTH CENTRAL ARIZONA.
MEANWHILE...MOSTLY CLEAR SKIES ARE EVIDENT ACROSS SOUTHEAST
ARIZONA...MORE SPECIFICALLY OVER MUCH OF GREENLEE...GRAHAM AND
COCHISE COUNTIES. IN ADDITION...CONVECTION HAS BEEN IGNITING OVER
THE SIERRA MADRES OF NORTHWEST CHIHUAHUA. THIS BAND OF STORMS SHOULD
CONTINUE TO LIFT TO THE NORTH WITH VARIOUS MODELS SUGGESTING THAT
ACTIVITY WILL GET STARTED ALONG THE INTERNATIONAL BORDER THIS
AFTERNOON. THAT SAID...WATER VAPOR IMAGERY SHOWS AN IMPULSE OVER
SOUTHERN SONORA MEXICO AND MOVING NORTHWARD WHICH HAS BEEN PART OF
THE IMPETUS FOR THE CURRENT DEVELOPMENT OVER THE SIERRA MADRES.
MODELS PICK UP ON THIS FEATURE WITH THE MODELS SHOWING IT MOVING
ACROSS NORTHERN SONORA MEXICO AND INTO SOUTHERN ARIZONA OVERNIGHT.
IN ADDITION...THE HRRR AND THE U OF A WRF-NAM SUGGEST THAT WE SHOULD
SEE LIGHT ACTIVITY THROUGH THE EARLY AFTERNOON...BUT CONVECTION WILL
IGNITE EITHER SIDE OF THE INTERNATIONAL BORDER AND SPREAD NORTH
DURING THE MID TO LATE AFTERNOON AND CONTINUE INTO THE EVENING
HOURS. SHOULD EVEN SEE CONVECTION CONTINUE AFTER MIDNIGHT TONIGHT AS
THE VORT MAX MOVES THROUGH THE AREA. ADJUSTED THE POP FORECAST FOR
THE 00Z-06Z PERIOD TO INCREASE CHANCES ALONG THE INTERNATIONAL
BORDER WEST OF NOGALES AND COVERING SOUTHERN PORTIONS OF THE TOHONO
O`ODHAM NATION.
AS THE SYSTEM FROM NORTHERN MEXICO MAKES ITS WAY NORTHWARD THROUGH
THIS EVENING AND OVERNIGHT...AND EVENTUALLY INTO THE NORTHERN PART
OF THE STATE BY LATE TUESDAY...THE FORCING FROM THIS SYSTEM SHOULD
RESULT IN SCATTERED STORM DEVELOPMENT OVER MOST OF THE DESERT/VALLEY
LOCATIONS AND SLIGHTLY BETTER CHANCES FOR THE HIGHER TERRAIN ON
TUESDAY.
BY WEDNESDAY THE PACIFIC STORM SYSTEM WILL BEGIN TO MOVE ALONG THE
COASTAL AREAS OF NORTHERN CALIFORNIA BY LATE WEDNESDAY OR EARLY
THURSDAY. THIS WILL RESULT IN WEST TO SOUTHWEST WINDS ALOFT AHEAD OF
THIS SYSTEM PUSHING MOISTURE TO THE EAST. RAIN CHANCES WILL DECREASE
FROM THE MIDDLE TO LATTER PART OF THE WEEK. AS THE PACIFIC LOW LIFTS
INTO OREGON OVER THE WEEKEND...THE HIGH TO THE EAST WILL RETROGRADE
A BIT FOR A WARMING TREND.
HIGHS WILL GENERALLY BE AROUND 3 TO 5 DEGS BELOW NORMAL TUESDAY...
THEN NEAR NORMAL FOR WEDNESDAY...AND SLIGHTLY ABOVE NORMAL FOR
THURSDAY. THEREAFTER...HIGHS ABOUT 3 TO 5 DEGS ABOVE NORMAL. LOWS
WILL BE AROUND 1 TO 3 DEGS ABOVE NORMAL FOR TUESDAY THROUGH FRIDAY
MORNINGS...THEN ABOUT 4 TO 6 DEGS ABOVE NORMAL FOR SATURDAY THROUGH
MONDAY.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
935 PM MDT MON AUG 5 2013
.UPDATE...
&&
.SHORT TERM...STRONG CONVECTION HAS MOVED OUT OF THE AREA. STILL
SOME ISOLATED WEAK SHOWERS MOVING INTO THE MOUNTAINS...WILL HOLD
ON TO THESE AND A SLIGHT CHANCE OF REDEVELOPING WEAK SHOWERS NEAR
THE EASTERN BORDER FOR A FEW MORE HOURS. UPDATING TO REMOVE POPS
ELSEWHERE.
&&
.AVIATION...VFR CONDITIONS THROUGH TUESDAY. SOME VARIATION IN WIND
DIRECTION BETWEEN W AND S AT KDEN/KAPA OVERNIGHT. ISOLATED HIGH
BASED STORMS EXPECTED TUESDAY AFTERNOON...BETTER COVERAGE WITH
MORE IMPACT POSSIBLE TUESDAY EVENING.
&&
.PREV DISCUSSION... /ISSUED 352 PM MDT MON AUG 5 2013/
SHORT TERM...CURRENT ANALYSIS SHOWS SCATTERED STORMS OVER THE
MOUNTAINS WITH A FEW JUST BEGINNING TO SPREAD EASTWARD ONTO THE
HIGHER TERRAIN NEAR THE WYOMING BORDER. STILL SEE THE MAIN THREAT
OF ANY SEVERE STORMS NORTHEAST OF A LINE FROM WELLINGTON TO FORT
MORGAN AND LIMON WHERE BEST COMBINATION OF DAYTIME HEATING AND
DEEPEST MOISTURE/INSTABILITY EXISTS WITH CAPES OF 1000-2000 J/KG.
FARTHER WEST INCLUDING THE I-25 URBAN CORRIDOR...TEMPERATURES WERE
FINALLY BEGINNING TO WARM POST SURGE...BUT STILL STRUGGLING TO
REACH CONVECTIVE TEMPS. AS A RESULT...NOT CERTAIN WE WILL SEE
STORMS BUT STILL HAVE A COUPLE HOURS TO WARM AND HELP BREAK THE
CAP. IN ANY CASE...DEWPOINTS WERE BEGINNING TO MIX SO THREAT OF
ANY STRONGER STORMS CLOSER TO THE FOOTHILLS LOOKS LOW BARRING ANY
STRONGER OUTFLOWS.
SHOWERS AND STORMS ARE EXPECTED TO DECREASE FROM WEST TO EAST
THROUGH THE COURSE OF THE EVENING AS UPPER LEVEL DIVERGENCE
ASSOCIATED WITH RIGHT REAR ENTRANCE REGION OF UPPER JET CONTINUES
TO PUSH EAST.
FOR TUESDAY...THE PLAINS FORECAST WILL LIKELY HINGE ON THE
POSSIBILITY OF ANOTHER SURGE OF SLIGHTLY COOLER BUT MORE MOIST
AIR. THIS WOULD BE FROM YET ANOTHER STORM COMPLEX LIKELY TO
ORIGINATE IN THE NORTHERN PLAINS AND ROLL SOUTHEAST THROUGH
NEBRASKA OVERNIGHT. AS A RESULT...HAVE COOLED OFF THE NORTHEAST
CORNER A BIT...RAISED DEWPOINTS...AND WILL KEEP A LITTLE BETTER
CHANCE OF STORMS ON THE PLAINS LATE IN THE AFTERNOON.
LONG TERM...CHANCE OF STORMS TO PERSIST ACROSS THE MOUNTAINS
THROUGH THE EVENING WITH SOME INCREASE IN SUBTROPICAL MOISTURE.
ACROSS PLAINS...AIRMASS LOOKING MORE MOIST WITH AN INCREASE IN LOW
LEVEL MOISTURE BUT A BIT MORE STABLE BEHIND AFTERNOON`S COLD
FRONT..NOW LOOKING LIKE THE BEST CHANCE FOR STORMS TO BE ALONG
FOOTHILLS AND PALMER DIVIDE. AFTER MIDNIGHT...THERE IS SOME
INCREASE IN MID LEVEL QG ASCENT AS UPPER TROUGH MOVES INTO THE
GREAT BASIN. THIS SHOULD ALLOW FOR AT LEAST A CHANCE OF STORMS
OVER THE MOUNTAINS WITH PERHAPS SOME INCREASE ACROSS THE PLAINS.
WITH THE INCREASE IN LOW LEVEL MOISTURE...SOME STORMS COULD
PRODUCE BRIEF MODERATE TO HEAVY RAINFALL. ON WEDNESDAY...UPPER
TROUGH TO SLOWLY MOVE ACROSS COLORADO WITH AN INCREASE IN MID
LEVEL QG ASCENT. CROSS SECTIONS STILL INDICATING DECENT MOISTURE
ACROSS AREA. ENOUGH SHEAR AND MID LEVEL ASCENT WILL HELP TO
INCREASE STORM CHANCES ACROSS MOUNTAINS IN AND NEAR FOOTHILLS BY
THE AFTERNOON AND WILL INCREASE POPS TO THE LIKELY CATEGORY.
COOLER AIRMASS TO LIMIT THE INTENSITY OF THE STORMS...STILL THE
POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH AN INCREASING THREAT OF
FLOODING ALONG THE FOOTHILLS. HIGHS TO COOL INTO THE MIDDLE 70S
ACROSS THE PLAINS. STORMS TO DECREASE DURING THE EVENING AS TROUGH
AXIS SHIFTS ACROSS THE EASTERN PLAINS...ENDING OVER MUCH OF THE
AREA AFTER MIDNIGHT. ON THURSDAY....UPPER TROUGH TO BE EAST OF THE
AREA WITH WEAK SUBSIDENCE SPREADING INTO NORTHWEST COLORADO. CROSS
SECTIONS STILL SHOW GOOD MOISTURE ACROSS THE AREA...MAINLY ACROSS
THE MOUNTAINS. WILL MAINTAIN THE CHANCE OF STORMS FOR THE HIGH
COUNTRY AND A SLIGHT CHANCE OVER THE PLAINS. TEMPERATURES TO WARM
SLIGHTLY...INTO THE LOWER AND MIDDLE 80S ACROSS THE PLAINS. ON
FRIDAY...SOUTHWEST FLOW ALOFT TO PREVAIL WITH UPPER HIGH CENTERED
OVER EASTERN TEXAS. FLOW TO BRING AN INCREASE IN SUBTROPICAL
MOISTURE ACROSS THE AREA... MAINLY ACROSS THE MOUNTAINS. BEST
CHANCE FOR STORMS TO BE OVER THE HIGH COUNTRY DURING THE AFTERNOON
AND EVENING.
FOR THE LATER DAYS SATURDAY THROUGH SUNDAY: SOUTHWEST FLOW ALOFT
TO PREVAIL WITH SUBTROPICAL MOISTURE STILL AFFECTING THE AREA.
LATEST MODELS KEEP SURFACE FRONT EAST OF THE AREA SATURDAY...SO
CHANCES FOR STORMS ACROSS PLAINS NOT EXPECTED TO INCREASE. WILL
MAINTAIN THE CHANCE FOR THUNDERSTORMS ACROSS THE MOUNTAINS DURING
THE AFTERNOON AND EVENING...WITH A SLIGHT CHANCE OVER THE PLAINS.
TEMPERATURES TO GRADUALLY WARM INTO THE MID AND UPPER 80S ACROSS
THE PLAINS.
AVIATION...THREAT OF AT LEAST SOME HIGH BASED CONVECTION IS HIGH
ENOUGH TO WARRANT POSSIBILITY OF GUSTY WINDS TIL AROUND 02Z-03Z.
MESOSCALE HRRR MODELS SUPPORTS THIS SCENARIO AS WELL. WILL ADDRESS
THUNDER THREAT AS NEEDED...BUT ONLY A CHANCE AT THIS POINT.
OTHERWISE WINDS WILL EVENTUALLY TRANSITION TO DRAINAGE WINDS
OVERNIGHT...AND THEN BACK TO NORTH/NORTHEASTERLIES BY 16Z-18Z
TUESDAY.
HYDROLOGY...LOOKS LIKE THE FOOTHILL BURN SCARS ARE ON THE EDGE
OF DEEPER MOISTURE AND HEAVIER RAIN THREAT. STRONGER STORMS ON
THE PLAINS WILL BE CAPABLE OF PRODUCING 1 TO 1.5 INCHES IN 40
MINUTES...WHILE STRONGER FOOTHILL STORMS COULD PRODUCE 0.5 TO
0.75 INCH. SIMILAR SITUATION EXPECTED TUESDAY.
ON WEDNESDAY...PRECIPITABLE WATER VALUES INCREASE AND MORE
EFFICIENT RAINERS ARE ANTICIPATED. STORM COVERAGE SHOULD ALSO BE
CONSIDERABLY HIGHER RESULTING IN A HIGHER THREAT OF FLOODING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....D-L
AVIATION/UPDATE...GIMMESTAD
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1129 PM MDT SAT AUG 3 2013
.UPDATE...
ISSUED AT 959 PM MDT SAT AUG 3 2013
UPDATED FOR EXPIRATION OF SEVERE TSTM WATCH. ALSO TO REFLECT
CURRENT PCPN TRENDS. WILL LEAVE FLASH FLOOD WATCH IN PLACE FOR EL
PASO COUNTY BECAUSE SOME MODERATE TO HEAVY RAIN IS CONTINUING OVER
PORTIONS OF SOUTHERN/SOUTHEAST EL PASO COUNTY.
UPDATE ISSUED AT 900 PM MDT SAT AUG 3 2013
UPDATED TO CANCEL FLASH FLOOD WATCH FOR TELLER COUNTY/RAMPART
RANGE...TO CANCEL SEVERE TSTM WATCH FOR TELLER COUNTY/PIKES PEAK
AREA AS WELL. ALSO UPDATED TO REFLECT CURRENT PCPN TRENDS.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 249 PM MDT SAT AUG 3 2013
...FLASH FLOODING THREAT FOR THE BURN SCARS AND SEVERE THUNDERSTORM
THREAT FOR THE SOUTHEAST PLAINS THROUGH THIS EVENING...
RICH LOW LEVEL MOISTURE IN PLACE ACROSS SOUTHEAST PLAINS AS OF EARLY
THIS AFTERNOON...WITH SFC DEW POINTS IN THE 60S. THIS IS BEING
ADVECTED IN BY LOW LEVEL EASTERLY FLOW. CLOUD COVER HAS HUNG IN
LONGER ACROSS THE PLAINS THIS AFTERNOON BUT IS ERODING ON WESTWARD
EDGE WHICH SHOULD ERODE CIN FROM WEST TO EAST AS THE AFTERNOON
PROGRESSES. MEANWHILE...MONSOON PLUME CONTINUES TO LAY ACROSS THE
REGION CAUGHT UP IN SOUTHWEST FLOW AROUND WEST SIDE OF SFC HIGH AND
SFC DEW POINT ACROSS THE MOUNTAINS ARE QUITE RESPECTABLE...IN THE
40S WITH SOME LOWER 30S ACROSS INTERIOR VALLEY OF LAKE/CHAFFEE
COUNTIES.
FOR THE REMAINDER OF THIS AFTERNOON AND EVENING...THUNDERSTORMS OVER
THE MOUNTAINS WILL SPREAD EASTWARD ACROSS THE ADJACENT PLAINS WITH
MODELS SUGGESTING ONE OR MORE THUNDERSTORM COMPLEXES TAKING SHAPE
AROUND 03Z BEFORE DROPPING TO THE SOUTHEAST INTO SOUTHWEST KS AND
TX/OK PANHANDLES TOWARDS MORNING. SPC MESO ANALYSIS AS OF 18Z
SHOWING 2000+ J/KG OF CAPE. 0-6KM SHEARS WILL BE RUNNING AROUND
30-35 KTS OF DEEP LAYER SHEAR. THUS...MULTICELL STORMS WILL PROBABLY
BE THE MAIN STORM THREAT...THOUGH COULD NOT RULE OUT AN ISOLATED
SUPERCELL ESPECIALLY WHERE LOW LEVEL EASTERLIES MAXIMIZE. THIS
WOULD MOST LIKELY OCCUR ACROSS NORTHERN SECTIONS OF THE FORECAST
AREA...PARTICULARLY KIOWA COUNTY.
OF POTENTIALLY EQUAL OR GREATER CONCERN WILL BE POTENTIAL FOR FLASH
FLOODING ON THE BURN SCARS...PARTICULARLY WALDO AND BLACK FOREST.
SOUTHEAST UPSLOPE FLOW COMBINED WITH HEATING...AND WEAK SHORTWAVE
ENERGY EMBEDDED IN MONSOON PLUME ALOFT SHOULD TRIGGER THUNDERSTORMS
OVER THE PIKES PEAK REGION THROUGH 2 PM...WITH A LINE OF
THUNDERSTORMS MOVING OFF TO THE EAST ACROSS THE WALDO AND BLACK
FOREST BURN SCARS BETWEEN 3 AND 6 PM. A MYRIAD OF SHORT RANGE HIGH
RES MODELS SHOW THIS...THOUGH WITH VARYING TIMING. OF COURSE...HAVE
SEEN THIS BEFORE IN THE MODELS AND HAD STORMS MIRACULOUSLY SPARE THE
BURN SCARS...BUT DEW POINTS SO HIGH (40S AND 50S) THREAT SHOULD BE
FAIRLY HIGH TODAY. FLASH FLOOD WATCH STILL LOOKS ON TRACK. THINK
THREAT SHOULD DIMINISH AFTER 8 PM...BUT HRRR OCCASIONALLY SHOWS
ANOTHER ROUND MOVING OFF AROUND 04Z SO WILL MAINTAIN THE MIDNIGHT
END TIME OF THE WATCH FOR NOW. FREQUENTLY THE HRRR OVERESTIMATES
THE INTENSITY OF ANY TRAILING ROUNDS OF CONVECTION.
THE WEST FORK BURN SCAR IS ALSO UNDER THE GUN TODAY FOR FLASH
FLOODING...THOUGH THREAT DOES NOT LOOK AS HIGH AS YESTERDAY. WITH
PRECIP WATERS RUNNING AROUND 150% OF NORMAL ACROSS THE WESTERN
PORTIONS OF CO...HEAVY RAIN WILL BE A THREAT WITH ANY THUNDERSTORMS
WHICH COULD CAUSE FLASH FLOODING SHOULD IT IMPACT THE WEST FORK BURN
SCAR. SO WILL BE MONITORING THIS REGION AS WELL.
OVERNIGHT...ACTIVITY SHOULD SHIFT EASTWARD AND EXIT THE AREA WITH
STRATUS SPREADING/DEVELOPING ACROSS SOUTHEAST COLORADO OVERNIGHT.
SUNDAY WILL BE HUMID AGAIN ACROSS THE SOUTHEAST PLAINS WITH DEW
POINTS IN THE 50S AND 60S IN THE MORNING AND MONSOON PLUME STILL
OVER THE REGION. MODELS SUGGEST LESS CONVECTION TOMORROW...AND EVEN
DRY SFC DEW POINTS ACROSS THE SOUTHEAST MTS A LITTLE IN THE
AFTERNOON STILL LOOKING AT CAPES AROUND 1500 J/KG ACROSS THE FAR
EAST PLAINS AND WITH MONSOON PLUME STILL OVERHEAD...AT LEAST THE
TYPICAL SCATTERED AFTERNOON AND EVENING THUNDERSTORMS. BURN SCARS
WILL BE UNDER THE GUN AGAIN AS USUAL...BUT THREAT APPEARS A LITTLE
LOWER THAN TODAY...SO WILL NOT HOIST ANY WATCHES AT THIS TIME.
LATER SHIFTS CAN GET A LOOK AT THE LATEST RUNS AND REASSESS.
OTHERWISE...TEMPERATURES TOMORROW SHOULD SKEW SLIGHTLY WARMER THAN
THOSE OF TODAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 249 PM MDT SAT AUG 3 2013
...SEASONAL MONSOON WILL REMAIN IN PLACE THROUGH NEXT WEEK...
MOIST PATTERN WILL CONTINUE. SOUTHWEST MONSOON WILL CONTINUE TO
TAKE AIM AT SOUTHERN COLORADO THROUGH MOST OF NEXT WEEK.
ADDITIONALLY...A LARGE UPPER TROUGH OVER THE NORTHERN SOUTHERN
CANADA AND THE NORTHERN TIER OF THE US...WILL SEND SURFACE
BOUNDARIES SOUTH THROUGH THE CENTRAL PLAINS AT TIMES...BACKING
THE MOISTURE UP AGAINST THE MOUNTAINS. THIS PATTERN SHOULD KEEP
PLENTY OF LOW LEVEL MOISTURE IN PLACE ACROSS THE PLAINS AND EAST
SLOPES OF THE MOUNTAINS. ALSO...PERIODS OF ENHANCED UPSLOPE FLOW
BEHIND THE BOUNDARIES WILL HELP TO LIFT THE AIR AND SQUEEZE OUT THE
PRECIPITATION ON A MORE WIDESPREAD BASIS ACROSS THE AREA. SO...ALL
SEEMS IN PLACE FOR A RATHER WET PERIOD ACROSS SOUTHERN
COLORADO...WITH PERIODS OF HEAVY RAIN AND FLASH FLOODING POSSIBLE
EACH DAY OF NEXT WEEK. SPECIFICS OF THE FORECAST ARE DIFFICULT BUT
INDICATIONS ARE THAT WE COULD SEE CONVECTIVE COMPLEXES AFFECTING THE
PLAINS MONDAY AND TUESDAY NIGHTS...A MORE WIDESPREAD AREA OF
PRECIPITATION WEDNESDAY INTO THURSDAY...AND THEN MORE SCATTERED
PRECIPITATION AGAIN FRIDAY INTO SATURDAY. ALL OF THESE DETAILS
ARE SUBJECT TO CHANGE. STAY TUNED. LW
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1125 PM MDT SAT AUG 3 2013
WITH ALL THE RAIN THAT FELL IN THE KCOS AND KPUB AREAS
TONIGHT...EXPECTING STRATUS AND POSSIBLY SOME FOG...RESULTING IN
MVFR OR IFR CONDITIONS THAT SHOULD END BY MIDMORNING SUNDAY.
EXPECTING KALS TO HAVE VFR CONDITIONS TONIGHT. THUNDERSTORMS WILL
ONCE AGAIN DEVELOP OVER THE MOUNTAINS ON SUNDAY AND MOVE OVER THE
LOWER ELEVATIONS FOR THE AFTERNOON AND EVENING HOURS. THUS ALL
THREE TERMINAL SITES WILL HAVE THE CHANCE FOR TSTMS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR COZ084-085.
&&
$$
UPDATE...28
SHORT TERM...KT
LONG TERM...LW
AVIATION...28
AREA FORECAST DISCUSSION
NWS NEW YORK NY
825 PM EDT MON AUG 5 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE EAST ON TUESDAY AS A WARM FRONT APPROACHES
FROM THE WEST. THE WARM FRONT WILL LIFT THROUGH DURING THURSDAY
MORNING...FOLLOWED BY A COLD FRONT ON SATURDAY. WEAK HIGH PRESSURE
WILL THEN RETURN INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
BKN-OVC HIGH CLOUDS ASSOCIATED WITH A MID LEVEL VORT MAX ARE
SPILLING INTO NYC METRO AND THE LOWER HUDSON VALLEY ATTM.
THERE COULD BE SOME CLEARING IN THOSE AREAS LATE TONIGHT PER
LATEST RAP AS THIS UPPER LEVEL FORCING MOVES TO THE EAST...DECIDED
TO BLEND WITH PREV FCST FOR NOW AND GO FROM MOSTLY CLOUDY THIS
EVENING TO PTCLDY LATE. CENTRAL/EASTERN PORTIONS OF CT/LONG ISLAND
SHOULD REMAIN MOSTLY CLEAR.
WILL AVE TO MONITOR IR SAT FOR CLOUD TRENDS THIS EVENING AND
ADJUST NIGHTTIME LOWS ACCORDINGLY WITH NEXT UPDATE. FOR NOW...
FCST TEMPERATURES TONIGHT WILL BE QUITE PLEASANT...BOTTOMING OUT
IN THE MID AND UPPER 60S IN/AROUND NYC...AND IN THE MID AND UPPER
50S ACROSS LONG ISLAND...MUCH OF NE NJ AND COASTAL CT. FOR THE
LOWER HUDSON VALLEY...INTERIOR PORTIONS OF SOUTHERN CT...AND THE
PINE BARRENS OF LONG ISLAND...EXPECTING STRONG RADIATIONAL COOLING
AND LOWS IN THE MID AND UPPER 40S. TEMPERATURES TONIGHT WILL BE
ANYWHERE FROM 10 TO 15 DEGREES BELOW AVG.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
HIGH PRES CONTINUES TO MOVE OFFSHORE TUESDAY MORNING...AND THEN
WILL MEANDER OVER THE WESTERN ATLANTIC THROUGH TUESDAY NIGHT. LOW
PRES WILL TRACK ACROSS THE NORTHERN PLAINS...AND WILL PULL A WARM
FRONT INTO THE REGION LATE TUESDAY AND TUESDAY NIGHT. A FEW LIGHT
SHOWERS ARE POSSIBLE ACROSS FAR WESTERN ZONES...TUESDAY AFTERNOON
AND EVENING...AND THEN MORE SHOWERS WILL ORGANIZE WEST OF THE AREA
TUESDAY NIGHT AS THE WARM FRONT PUSHES CLOSER. BASED ON THE LATEST
NAM/GFS QPF FIELDS...HAVING A HARD TIME JUSTIFYING POPS EAST OF
THE HUDSON RIVER THROUGH TUESDAY NIGHT. WILL THEREFORE GO WITH A
DRY FORECAST ON TUESDAY...AND THEN CHANCE POPS FOR THE WESTERN
THIRD OF THE CWA TUESDAY NIGHT WITH THE SHOWERS MAINLY COMING
AFTER MIDNIGHT.
ANOTHER PLEASANT DAY ON TAP FOR TUESDAY WITH HIGHS IN THE UPPER
70S TO LOWER 80S. LOWS TUESDAY NIGHT WILL BE IN THE MID TO UPPER
60S IN/AROUND NYC AND IN THE UPPER 50S TO LOW 60S ELSEWHERE.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
GLOBAL MODELS IN MODEST AGREEMENT WITH THE OVERALL UPPER PATTERN
THROUGH THE LONG TERM PERIOD...ALTHOUGH TIMING OF FEATURES BEGIN
TO DIVERGE FOR THE SECOND HALF OF THE PERIOD. WEAK UPPER LEVEL
RIDGING WILL MOVE ACROSS THE AREA ON WED. MEANWHILE A CUTOFF LOW
PRES SYSTEM OVER CENTRAL CANADA WILL TRACK EASTWARD AS ANOTHER
SHORTWAVE FURTHER N MERGES WITH IT. THIS WILL RESULT IN A LARGE
UPPER LEVEL TROUGH/CUTOFF LOW PRES OVER EASTERN CANADA BY THE
WEEKEND...WITH THE LOCAL AREA ON THE SOUTHERN EDGE OF THIS
FEATURE. TO THE S...HEIGHTS WILL RISE AND BATTLE THE TROUGH TO THE
N...BUT THE TROUGH APPEARS TO WIN OUT AND THE HOT TEMPERATURES
(AOA 90 DEGREES) WILL REMAIN S OF THE AREA.
AT THE SFC...AS A WARM FRONT APPROACHES FROM THE SW...ISENTROPIC
LIFT WILL INCREASE WITH WAA RAIN DEVELOPING ON WED. THERE IS SOME
QUESTION ON TIMING DUE TO RETREATING HIGH PRES...AND MAY BE A BIT
EARLY BRINGING IN POPS...BUT THIS CAN BE REFINED IN SUBSEQUENT
FORECAST UPDATES. DO THINK THE GFS IS TOO FAST...WHICH IS TYPICAL
IN THIS TYPE OF SCENARIO. RAIN BECOMES LIKELY ACROSS THE AREA WED
NIGHT...AND WITH SHOWALTER VALUES AROUND ZERO OR SLIGHTLY
BELOW...EXPECT SOME RUMBLES OF THUNDER AS WELL. HUMIDITY LEVELS
WILL NOTICEABLY INCREASE AS WELL.
WARM FRONT LIFTS THROUGH THE AREA ON THU WITH ORGANIZED RAIN
SHIELD MOVING NE. THIS IS WHERE MODELS BEGIN TO DIVERGE...ALTHOUGH
DO THINK A TROUGH REMAINS OVER THE AREA WITH SHOWERS AROUND UNTIL
A COLD FRONT MOVES THROUGH EITHER FRI OR SAT. MOISTURE LEVELS MAY
HAVE ENOUGH TIME OF INCREASE THROUGH THE COLUMN DURING THIS TIME
WITH A SLY FLOW...THEREFORE THERE IS THE CHANCE FOR HEAVY RAIN
WITH THE COLD FRONTAL PASSAGE. NOT CONFIDENCE THAT THIS WILL
RESULT IN FLASH FLOODING...SO WILL NOT INCLUDE IN THE HWO AT THIS
TIME.
WEAK HIGH PRES BUILDS IN AT THE SFC BEHIND THE FRONT RESULTING IN
DRY...SEASONABLE WEATHER INTO EARLY NEXT WEEK.
TEMPS WILL BE NEAR NORMAL LEVELS THROUGH THE PERIOD.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT AND OFFSHORE
TUESDAY.
VFR THRU THE TAF PERIOD BUT WITH SOME POSSIBILITY FOR 30 HR TAF
SITES TO HAVE SOME LIGHT SHOWERS AND MVFR CONDITIONS FOR 0-6Z WED.
WINDS WILL BE DECREASING TO LESS THAN 10 KT TONIGHT. SEA BREEZE
MOVING INTO KJFK BUT WILL TAKE AN EXTRA HOUR TO MOVE NEAR KEWR AND
KLGA WHILE WEAKENING IN THE PROCESS. SO...WINDS WILL BECOME
ESSENTIALLY LIGHT AND VARIABLE. HIGH CLOUDS WILL BE STREAMING IN
FROM THE WEST.
FOR TUESDAY...WINDS PICK UP OUT OF THE SOUTHEAST TO AROUND 10-15
KT BY LATE AFTERNOON AND THEN DECREASE AGAIN BY THE EVENING.
CLOUDS CONTINUE TO INCREASE...EVENTUALLY LOWERING AND THICKENING.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: WIND SPEED COULD BE OCCASIONALLY A FEW KT
HIGHER THAN FORECAST BEFORE 02Z. FOR TUESDAY...WIND SPEED MAY BE
OFF BY A FEW KT.
KLGA FCSTER COMMENTS: LOW CONFIDENCE FOR WIND DIRECTION IN THE
2-4Z TIME FRAME. COULD BE JUST LIGHT AND VARIABLE. FOR
TUESDAY...WIND SPEED MAY BE OFF BY A FEW KT.
KEWR FCSTER COMMENTS: FOR TUESDAY...WIND SPEED MAY BE OFF BY A FEW
KT.
KTEB FCSTER COMMENTS: FOR TUESDAY...WIND SPEED MAY BE OFF BY A FEW
KT.
KHPN FCSTER COMMENTS: FOR TUESDAY...WIND SPEED MAY BE OFF BY A FEW
KT.
KISP FCSTER COMMENTS: WIND DIRECTION COULD BE OFF BY 30-50 DEGREES
EARLY THIS EVENING. FOR TUESDAY...WIND SPEED MAY BE OFF BY A FEW
KT.
.OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY...
.TUE NGT...VFR.
.WED-WED NGT...WARM FRONT APPROACHES. AREAS MVFR OR LOWER...MAINLY
WED NGT. CHC FOR TSTMS.
.THU-THU NIGHT...CHANCE OF TSTMS. MVFR OR LOWER AT TIMES.
.FRI...SCT TSTMS POSSIBLE. MVFR OR LOWER POSSIBLE.
.SAT...TSTMS POSSIBLE WITH A COLD FRONTAL PASSAGE.
&&
.MARINE...
TRANQUIL CONDS WITH WINDS/SEAS BELOW SCA CRITERIA THROUGH TUESDAY
NIGHT AS HIGH PRES INFLUENCES THE WATERS.
WINDS ARE EXPECTED TO REMAIN BLO SCA LEVELS THROUGH THE REMAINDER
OF THE PERIOD. A PROLONGED SLY FLOW MAY CAUSE MARGINAL SCA SEAS ON
THE OCEAN FROM TIME TO TIME WED NIGHT THROUGH THU NIGHT.
&&
.HYDROLOGY...
GENERALLY LIGHT QPF WITH NO HYDRO ISSUES EXPECTED TUESDAY NIGHT.
THERE IS SOME VARIABILITY IN RAINFALL TOTALS AMONGST THE GUIDANCE
WED INTO THU. GENERALLY EXPECT ANYWHERE FROM 1/2 TO 1 1/2 INCHES
WITH LOCALLY HIGHER AMOUNTS
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GOODMAN/24/MPS
NEAR TERM...GOODMAN/MPS
SHORT TERM...MPS
LONG TERM...24
AVIATION...JM
MARINE...GOODMAN/24/MPS
HYDROLOGY...24/MPS
AREA FORECAST DISCUSSION
NWS ALBANY NY
320 PM EDT SUN AUG 4 2013
.SYNOPSIS...
A COOLER AIR MASS WILL FILTER INTO THE REGION AS A COLD FRONT MOVES
ACROSS THE REGION TODAY. A FEW SHOWERS AND THUNDERSTORMS WILL
OCCUR...BUT MOST OF THE TIME IT WILL BE RAIN FREE. BELOW NORMAL
TEMPERATURES FOR THIS TIME OF THE YEAR WILL CONTINUE INTO EARLY NEXT
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 115 PM...A BKN LINE OF SHOWERS/TSTMS EXTENDED FROM NRN NH TO
SOUTHERN VT AND THEN TO THE SOUTHEAST CATSKILLS. THIS LINE SHOWS UP
WELL ON STLT PICS AS WELL. HAVE RAISED POPS TO 50 PERCENT OVER THE
CENTRAL PART OF THE FORECAST AREA AND 40 PERCENT OVER THE SOUTHEAST.
OTHERWISE NO CHANGES MADE TO THE PREVIOUS GRIDDED FORECASTS.
.PREVIOUS DISCUSSION...
FOR ALL THESE REASONS...WILL KEEP CHANCE SHOWER/THUNDER WITH THE
MENTION OF SMALL HAIL WITH THIS PACKAGE. HOURLY TEMPERATURES WERE
GENERALLY RUNNING 3 DEGREES OR HIGHER THAN THE PREVIOUSLY PROJECTED
HOURLY TEMPS SO WENT AHEAD RE-TOOLED. DID RAISE A FEW TEMPERATURES
2-3 DEGREES...MAINLY IN THE MID HUDSON VALLEY. OTHERWISE LEFT THEM
ALONE.
LOOK FOR HIGH TEMPERATURES 70 TO 75 VALLEY AREAS...UPPER 70S MID
HUDSON VALLEY BUT ONLY IN THE 60S ACROSS THE ELEVATED TERRAIN. A
BREEZE WILL PICK UP FROM THE NORTHWEST 10 TO 15 MPH...GUSTING TO 25
OR MORE IN MORE WIND PRONE AREAS. THE RUC13 SUGGESTS SBCAPES AROUND
1K J/KG WITH WET BULB ZERO HEIGHTS FALLING TO NEAR 8K FEET BY EARLY
AFTERNOON SO THE MENTION OF SMALL HAIL REMAINS IN THE FORECAST.
WITH THE LOSS OF DAYTIME HEATING AND PASSAGE OF THE LAST IN THE
SERIES OF FROPA/S...A CLEARING SKY THIS EVENING. WINDS SHOULD
DECOUPLE AS WE WATCH TEMPERATURES FALL RATHER QUICKLY AS DEWPOINTS
DROP BACK INTO THE 40S. LOWS OVERNIGHT WILL MAINLY BE IN THE 40S
WITH AROUND 50 FOR THE IMMEDIATE CAPITAL REGION AND POINTS SOUTH
ALONG THE HUDSON RIVER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
A LARGE CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE REGION AND
CONTROL OUR WEATHER MONDAY THROUGH MONDAY NIGHT. A MAINLY CLEAR
SKY IS FORECAST BUT IT WILL BE COOL DURING
THIS PERIOD WITH LOWS GENERALLY IN THE 40S TO AROUND 50. HIGHS
IN THE UPPER 60S AND MID 70S...WITH A GRADUAL INCREASE EXPECTED
TUESDAY AFTERNOON.
WARM ADVECTION IS EXPECTED TO UNFOLD UPSTREAM OF THE CWFA WITH
VARIOUS MODELS VARYING ON THE TIMING OF THIS WITH THE LATEST
ECMWF/GGEM THE SLOWEST WITH THE ONSET OF THIS WAA. WE WILL PLACE A
SLIGHT CHANCE POPS FOR PORTIONS OF THE SCHOHARIE VALLEY...WESTERN
MOHAWK VALLEY AND ADIRONDACKS DURING THE AFTERNOON HOURS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WILL START TO SHIFT EAST OF THE AREA ON TUESDAY NIGHT.
THIS WILL ALLOW FOR A MOIST SOUTHERLY FLOW TO RETURN TO THE
REGION...WHICH WILL START TO INCREASE THE CLOUDS AND RETURN THE
THREAT FOR RAINFALL. STILL...MOST AREAS WILL HAVE ANOTHER COOL NIGHT
ON TUES NIGHT WITH MINS IN THE UPPER 40S TO UPPER 50S...AS THE
CLOUDS WON/T BE TOO THICK JUST YET AND ANY SHOWER ACTIVITY LOOKS
RATHER SCATTERED IN NATURE AND LIMITED TO JUST SOUTHWESTERN PARTS OF
THE AREA.
A WARM FRONT WILL MOVE ACROSS THE AREA FOR WEDNESDAY. THE BEST CHC
OF SEEING A SHOWER WILL BE FOR SOUTHERN AND WESTERN AREAS. MAX TEMPS
LOOK SIMILAR TO RECENT DAYS WITH 70S FOR MOST PLACES ALTHOUGH IT
WILL START TO FEEL A LITTLE MORE MUGGY THAN RECENT DAYS...WITH
DEWPOINTS STARTING TO CREEP UP IN THE 60S.
THE MODELS AREN/T IN EXACT AGREEMENT REGARDING THE TIMING OF A COLD
FRONT. AT SOME POINT BETWEEN WED NIGHT AND THURSDAY NIGHT...A COLD
FRONT LOOKS TO MOVE ACROSS THE REGION. A WAVE OF LOW PRESSURE MAY
DEVELOP ALONG THIS BOUNDARY...INCREASING THE THREAT FOR SHOWERS AND
THUNDERSTORMS. WITH PWAT VALUES RISING TO NEARLY TWO INCHES...HEAVY
RAINFALL MAY ACCOMPANY ANY OF THE SHOWERS OR THUNDERSTORMS.
DEPENDING ON THE AMOUNT OF INSTABILITY AND TIMING OF THE FRONT ON
THURSDAY...WE MAY HAVE TO WATCH FOR THE POTENTIAL FOR SOME STRONG
TSTMS ON THURSDAY AS WELL...ALTHOUGH THE MAIN THREAT LOOKS TO BE
HEAVY RAINFALL AT THIS POINT. MIN TEMPS ON WED NIGHT AND THURSDAY
NIGHT WILL BE MAINLY IN THE 60S...WITH 70S TO LOW 80S DURING THE DAY
ON THURSDAY.
BEHIND THE FRONT...THE THREAT FOR RAIN SHOULD DIMINISH. SOUTHEASTERN
PARTS OF THE AREA MAY CONTINUE TO SEE A THREAT FOR RAIN SHOWERS ON
FRIDAY DEPENDING ON HOW QUICKLY THE FRONT EXITS THE REGION AND IF IT
STALLS NEARBY. DEWPOINTS WILL DROP SOMEWHAT ON FRIDAY...ALTHOUGH
THE BEST PUSH OF DRY AIR MAY NOT ARRIVE UNTIL LATER IN THE WEEKEND.
MAX TEMPS ON FRIDAY WILL BE NEAR NORMAL...WITH VALLEY TEMPS IN THE
LOW 80S.
IT SHOULD BE DRY FOR FRIDAY NIGHT INTO SATURDAY FOR MOST
PLACES...ALTHOUGH AN UPPER LEVEL DISTURBANCE PASSING TO THE NORTH
MAY ALLOW FOR A SHOWER ACROSS THE ADIRONDACKS. TEMPS WILL CONTINUE
RUN CLOSE TO SEASONAL NORMALS.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
A DISCRETE SURFACE TROUGH AND UPPER LEVEL DISTURBANCE HAS TRIGGERED
SHOWERS AND THUNDERSTORMS ACROSS KGFL AND KALB ALREADY TODAY. THIS
BROKEN LINE HAS PUSHED SOUTH AND EAST OF THESE TAF SITES AND COULD
IMPACT KPSF/KPOU SOON. BEHIND THIS FEATURE STILL SOME WIDELY
SCATTERED SHOWERS AND PERHAPS A THUNDERSTORM SO HAVE ASSIGNED VCSH
TO THE TAFS UNTIL 22Z-00Z (LATEST AT KPSF AND KPOU). THESE SHOWERS
AND STORMS COULD BRIEFLY LOWER CONDITIONS TO MVFR OR PERHAPS
IFR...BUT ONLY FOR A VERY BRIEF TIME.
A GUSTY NORTHWEST BREEZE 10-15 KTS WILL DIMINISH TOWARD DAYBREAK AS
WELL.
OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH THIS EVENING. SCT-BKN
CU BASES GENERALLY AROUND 5000 FEET WILL DISSIPATE TOWARD DARK. WE
ARE CONCERNED ABOUT IFR AT MAINLY KGFL OVERNIGHT BUT PROBABLY JUST
ENOUGH MIXING TO PREVENT IFR FOG AT THE OTHER SITES.
ANY FOG DISSIPATE BY DAYBREAK TOMORROW WITH A GREAT FLYING DAY ON
TAP. THE DAY WILL SEE FEW IF ANY SENSIBLE CLOUDS...UNRESTRICTED
VISIBILITY AND A NORTH TO NORTHWEST WIND 10KTS OR LESS.
OUTLOOK...
MONDAY NIGHT: LOW OPERATIONAL IMPACT. NO SIG WX.
TUESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
WEDNESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
FRIDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
&&
.FIRE WEATHER...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON
TODAY AS THE LAST IN A SERIES OF UPPER LEVEL DISTURBANCES MOVES
ACROSS THE REGION.
RH VALUES WILL LOWER TO BETWEEN 45 AND 65 PERCENT ON SUNDAY...AND
RECOVER TO GREATER THAN 90 PERCENT OVERNIGHT.
WEST-NORTHWEST WINDS WILL INCREASE TO 10 TO 20 MPH WITH GUSTS OF
25 TO 30 MPH BY THIS AFTERNOON...AND BECOME LIGHT LATER TONIGHT AS
THE SURFACE RIDGE BUILDS INTO THE REGION.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THROUGH THE PERIOD.
AS ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
OCCUR TODAY AS ANOTHER IN A SERIES OF UPPER LEVEL DISTURBANCES AND
FRONTAL BOUNDARIES CROSS THE REGION. BASIN AVERAGE QPF AMOUNTS FOR
THE REST OF THE WEEKEND WILL BE UNDER A QUARTER OF AN INCH...SO THE
RAINFALL WILL HAVE LITTLE IMPACT ON AREA STREAMS AND RIVERS. DRY
WEATHER IS EXPECTED MONDAY AND TUESDAY. NEXT CHANCE FOR RAINFALL
ARRIVES LATER WEDNESDAY.
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/BGM
NEAR TERM...GJM/HWJIV/BGM
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...HWJIV
FIRE WEATHER...FRUGIS
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
152 PM EDT SUN AUG 4 2013
.SYNOPSIS...
A COOLER AIR MASS WILL FILTER INTO THE REGION AS A COLD FRONT MOVES
ACROSS THE REGION TODAY. A FEW SHOWERS AND THUNDERSTORMS WILL
OCCUR...BUT MOST OF THE TIME IT WILL BE RAIN FREE. BELOW NORMAL
TEMPERATURES FOR THIS TIME OF THE YEAR WILL CONTINUE INTO EARLY NEXT
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 115 PM...A BKN LINE OF SHOWERS/TSTMS EXTENDED FROM NRN NH TO
SOUTHERN VT AND THEN TO THE SOUTHEAST CATSKILLS. THIS LINE SHOWS UP
WELL ON STLT PICS AS WELL. HAVE RAISED POPS TO 50 PERCENT OVER THE
CENTRAL PART OF THE FORECAST AREA AND 40 PERCENT OVER THE SOUTHEAST.
OTHERWISE NO CHANGES MADE TO THE PREVIOUS GRIDDED FORECASTS.
.PREVIOUS DISCUSSION...
FOR ALL THESE REASONS...WILL KEEP CHANCE SHOWER/THUNDER WITH THE
MENTION OF SMALL HAIL WITH THIS PACKAGE. HOURLY TEMPERATURES WERE
GENERALLY RUNNING 3 DEGREES OR HIGHER THAN THE PREVIOUSLY PROJECTED
HOURLY TEMPS SO WENT AHEAD RE-TOOLED. DID RAISE A FEW TEMPERATURES
2-3 DEGREES...MAINLY IN THE MID HUDSON VALLEY. OTHERWISE LEFT THEM
ALONE.
LOOK FOR HIGH TEMPERATURES 70 TO 75 VALLEY AREAS...UPPER 70S MID
HUDSON VALLEY BUT ONLY IN THE 60S ACROSS THE ELEVATED TERRAIN. A
BREEZE WILL PICK UP FROM THE NORTHWEST 10 TO 15 MPH...GUSTING TO 25
OR MORE IN MORE WIND PRONE AREAS. THE RUC13 SUGGESTS SBCAPES AROUND
1K J/KG WITH WET BULB ZERO HEIGHTS FALLING TO NEAR 8K FEET BY EARLY
AFTERNOON SO THE MENTION OF SMALL HAIL REMAINS IN THE FORECAST.
WITH THE LOSS OF DAYTIME HEATING AND PASSAGE OF THE LAST IN THE
SERIES OF FROPA/S...A CLEARING SKY THIS EVENING. WINDS SHOULD
DECOUPLE AS WE WATCH TEMPERATURES FALL RATHER QUICKLY AS DEWPOINTS
DROP BACK INTO THE 40S. LOWS OVERNIGHT WILL MAINLY BE IN THE 40S
WITH AROUND 50 FOR THE IMMEDIATE CAPITAL REGION AND POINTS SOUTH
ALONG THE HUDSON RIVER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
A LARGE CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE REGION AND
CONTROL OUR WEATHER MONDAY THROUGH MONDAY NIGHT. A MAINLY CLEAR
SKY IS FORECAST BUT IT WILL BE COOL DURING
THIS PERIOD WITH LOWS GENERALLY IN THE 40S TO AROUND 50. HIGHS
IN THE UPPER 60S AND MID 70S...WITH A GRADUAL INCREASE EXPECTED
TUESDAY AFTERNOON.
WARM ADVECTION IS EXPECTED TO UNFOLD UPSTREAM OF THE CWFA WITH
VARIOUS MODELS VARYING ON THE TIMING OF THIS WITH THE LATEST
ECMWF/GGEM THE SLOWEST WITH THE ONSET OF THIS WAA. WE WILL PLACE A
SLIGHT CHANCE POPS FOR PORTIONS OF THE SCHOHARIE VALLEY...WESTERN
MOHAWK VALLEY AND ADIRONDACKS DURING THE AFTERNOON HOURS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WILL START TO SHIFT EAST OF THE AREA ON TUESDAY NIGHT.
THIS WILL ALLOW FOR A MOIST SOUTHERLY FLOW TO RETURN TO THE
REGION...WHICH WILL START TO INCREASE THE CLOUDS AND RETURN THE
THREAT FOR RAINFALL. STILL...MOST AREAS WILL HAVE ANOTHER COOL NIGHT
ON TUES NIGHT WITH MINS IN THE UPPER 40S TO UPPER 50S...AS THE
CLOUDS WON/T BE TOO THICK JUST YET AND ANY SHOWER ACTIVITY LOOKS
RATHER SCATTERED IN NATURE AND LIMITED TO JUST SOUTHWESTERN PARTS OF
THE AREA.
A WARM FRONT WILL MOVE ACROSS THE AREA FOR WEDNESDAY. THE BEST CHC
OF SEEING A SHOWER WILL BE FOR SOUTHERN AND WESTERN AREAS. MAX TEMPS
LOOK SIMILAR TO RECENT DAYS WITH 70S FOR MOST PLACES ALTHOUGH IT
WILL START TO FEEL A LITTLE MORE MUGGY THAN RECENT DAYS...WITH
DEWPOINTS STARTING TO CREEP UP IN THE 60S.
THE MODELS AREN/T IN EXACT AGREEMENT REGARDING THE TIMING OF A COLD
FRONT. AT SOME POINT BETWEEN WED NIGHT AND THURSDAY NIGHT...A COLD
FRONT LOOKS TO MOVE ACROSS THE REGION. A WAVE OF LOW PRESSURE MAY
DEVELOP ALONG THIS BOUNDARY...INCREASING THE THREAT FOR SHOWERS AND
THUNDERSTORMS. WITH PWAT VALUES RISING TO NEARLY TWO INCHES...HEAVY
RAINFALL MAY ACCOMPANY ANY OF THE SHOWERS OR THUNDERSTORMS.
DEPENDING ON THE AMOUNT OF INSTABILITY AND TIMING OF THE FRONT ON
THURSDAY...WE MAY HAVE TO WATCH FOR THE POTENTIAL FOR SOME STRONG
TSTMS ON THURSDAY AS WELL...ALTHOUGH THE MAIN THREAT LOOKS TO BE
HEAVY RAINFALL AT THIS POINT. MIN TEMPS ON WED NIGHT AND THURSDAY
NIGHT WILL BE MAINLY IN THE 60S...WITH 70S TO LOW 80S DURING THE DAY
ON THURSDAY.
BEHIND THE FRONT...THE THREAT FOR RAIN SHOULD DIMINISH. SOUTHEASTERN
PARTS OF THE AREA MAY CONTINUE TO SEE A THREAT FOR RAIN SHOWERS ON
FRIDAY DEPENDING ON HOW QUICKLY THE FRONT EXITS THE REGION AND IF IT
STALLS NEARBY. DEWPOINTS WILL DROP SOMEWHAT ON FRIDAY...ALTHOUGH
THE BEST PUSH OF DRY AIR MAY NOT ARRIVE UNTIL LATER IN THE WEEKEND.
MAX TEMPS ON FRIDAY WILL BE NEAR NORMAL...WITH VALLEY TEMPS IN THE
LOW 80S.
IT SHOULD BE DRY FOR FRIDAY NIGHT INTO SATURDAY FOR MOST
PLACES...ALTHOUGH AN UPPER LEVEL DISTURBANCE PASSING TO THE NORTH
MAY ALLOW FOR A SHOWER ACROSS THE ADIRONDACKS. TEMPS WILL CONTINUE
RUN CLOSE TO SEASONAL NORMALS.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
A DISCRETE SURFACE TROUGH AND UPPER LEVEL DISTURBANCE HAS TRIGGERED
SHOWERS AND THUNDERSTORMS ACROSS KGFL AND KALB ALREADY TODAY. THIS
BROKEN LINE HAS PUSHED SOUTH AND EAST OF THESE TAF SITES AND COULD
IMPACT KPSF/KPOU SOON. BEHIND THIS FEATURE STILL SOME WIDELY
SCATTERED SHOWERS AND PERHAPS A THUNDERSTORM SO HAVE ASSIGNED VCSH
TO THE TAFS UNTIL 22Z-00Z (LATEST AT KPSF AND KPOU). THESE SHOWERS
AND STORMS COULD BRIEFLY LOWER CONDITIONS TO MVFR OR PERHAPS
IFR...BUT ONLY FOR A VERY BRIEF TIME.
A GUSTY NORTHWEST BREEZE 10-15 KTS WILL DIMINISH TOWARD DAYBREAK AS
WELL.
OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH THIS EVENING. SCT-BKN
CU BASES GENERALLY AROUND 5000 FEET WILL DISSIPATE TOWARD DARK. WE
ARE CONCERNED ABOUT IFR AT MAINLY KGFL OVERNIGHT BUT PROBABLY JUST
ENOUGH MIXING TO PREVENT IFR FOG AT THE OTHER SITES.
ANY FOG DISSIPATE BY DAYBREAK TOMORROW WITH A GREAT FLYING DAY ON
TAP. THE DAY WILL SEE FEW IF ANY SENSIBLE CLOUDS...UNRESTRICTED
VISIBILITY AND A NORTH TO NORTHWEST WIND 10KTS OR LESS.
OUTLOOK...
MONDAY THROUGH TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY THROUGH THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF
SHRA...TSRA.
&&
.FIRE WEATHER...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON
TODAY AS THE LAST IN A SERIES OF UPPER LEVEL DISTURBANCES MOVES
ACROSS THE REGION.
RH VALUES WILL LOWER TO BETWEEN 45 AND 65 PERCENT ON SUNDAY...AND
RECOVER TO GREATER THAN 90 PERCENT OVERNIGHT.
WEST-NORTHWEST WINDS WILL INCREASE TO 10 TO 20 MPH WITH GUSTS OF
25 TO 30 MPH BY THIS AFTERNOON...AND BECOME LIGHT LATER TONIGHT AS
THE SURFACE RIDGE BUILDS INTO THE REGION.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THROUGH THE PERIOD.
AS ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
OCCUR TODAY AS ANOTHER IN A SERIES OF UPPER LEVEL DISTURBANCES AND
FRONTAL BOUNDARIES CROSS THE REGION. BASIN AVERAGE QPF AMOUNTS FOR
THE REST OF THE WEEKEND WILL BE UNDER A QUARTER OF AN INCH...SO THE
RAINFALL WILL HAVE LITTLE IMPACT ON AREA STREAMS AND RIVERS. DRY
WEATHER IS EXPECTED MONDAY AND TUESDAY. NEXT CHANCE FOR RAINFALL
ARRIVES LATER WEDNESDAY.
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/BGM
NEAR TERM...GJM/HWJIV/BGM
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...HWJIV
FIRE WEATHER...FRUGIS
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
142 PM EDT SUN AUG 4 2013
.SYNOPSIS...
A COOLER AIR MASS WILL FILTER INTO THE REGION AS A COLD FRONT MOVES
ACROSS THE REGION TODAY. A FEW SHOWERS AND THUNDERSTORMS ARE
POSSIBLE...BUT MOST OF THE TIME IT SHOULD REMAIN DRY. BELOW NORMAL
TEMPERATURES FOR THIS TIME OF THE YEAR WILL CONTINUE INTO EARLY NEXT
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 AM EDT...SHOWERS HAD DISSIPATED TO THE EAST OF LAKE
ONTARIO. HOWEVER...ANOTHER CLUSTER HAS DEVELOPED IN ONEIDA COUNTY.
CLOUDS WERE BEGINNING TO PERCOLATE AS THE MID LEVELS OF THE
ATMOSPHERE COOL...STEEPENING THE LOW LEVEL LAPSE AND INSTABILITY.
ALSO...H20 WATER VAPOR LOOP INDICATES A SERIES OF DISTURBANCES
HEADING WAY LATER TODAY.
FOR ALL THESE REASONS...WILL KEEP CHANCE SHOWER/THUNDER WITH THE
MENTION OF SMALL HAIL WITH THIS PACKAGE. HOURLY TEMPERATURES WERE
GENERALLY RUNNING 3 DEGREES OR HIGHER THAN THE PREVIOUSLY PROJECTED
HOURLY TEMPS SO WENT AHEAD RE-TOOLED. DID RAISE A FEW TEMPERATURES
2-3 DEGREES...MAINLY IN THE MID HUDSON VALLEY. OTHERWISE LEFT THEM
ALONE.
LOOK FOR HIGH TEMPERATURES 70 TO 75 VALLEY AREAS...UPPER 70S MID
HUDSON VALLEY BUT ONLY IN THE 60S ACROSS THE ELEVATED TERRAIN. A
BREEZE WILL PICK UP FROM THE NORTHWEST 10 TO 15 MPH...GUSTING TO 25
OR MORE IN MORE WIND PRONE AREAS. THE RUC13 SUGGESTS SBCAPES AROUND
1K J/KG WITH WET BULB ZERO HEIGHTS FALLING TO NEAR 8K FEET BY EARLY
AFTERNOON SO THE MENTION OF SMALL HAIL REMAINS IN THE FORECAST.
WITH THE LOSS OF DAYTIME HEATING AND PASSAGE OF THE LAST IN THE
SERIES OF FROPA/S...A CLEARING SKY THIS EVENING. WINDS SHOULD
DECOUPLE AS WE WATCH TEMPERATURES FALL RATHER QUICKLY AS DEWPOINTS
DROP BACK INTO THE 40S. LOWS OVERNIGHT WILL MAINLY BE IN THE 40S
WITH AROUND 50 FOR THE IMMEDIATE CAPITAL REGION AND POINTS SOUTH
ALONG THE HUDSON RIVER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
A LARGE CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE REGION AND
CONTROL OUR WEATHER MONDAY THROUGH MONDAY NIGHT. A MAINLY CLEAR
SKY IS FORECAST BUT IT WILL BE COOL DURING
THIS PERIOD WITH LOWS GENERALLY IN THE 40S TO AROUND 50. HIGHS
IN THE UPPER 60S AND MID 70S...WITH A GRADUAL INCREASE EXPECTED
TUESDAY AFTERNOON.
WARM ADVECTION IS EXPECTED TO UNFOLD UPSTREAM OF THE CWFA WITH
VARIOUS MODELS VARYING ON THE TIMING OF THIS WITH THE LATEST
ECMWF/GGEM THE SLOWEST WITH THE ONSET OF THIS WAA. WE WILL PLACE A
SLIGHT CHANCE POPS FOR PORTIONS OF THE SCHOHARIE VALLEY...WESTERN
MOHAWK VALLEY AND ADIRONDACKS DURING THE AFTERNOON HOURS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WILL START TO SHIFT EAST OF THE AREA ON TUESDAY NIGHT.
THIS WILL ALLOW FOR A MOIST SOUTHERLY FLOW TO RETURN TO THE
REGION...WHICH WILL START TO INCREASE THE CLOUDS AND RETURN THE
THREAT FOR RAINFALL. STILL...MOST AREAS WILL HAVE ANOTHER COOL NIGHT
ON TUES NIGHT WITH MINS IN THE UPPER 40S TO UPPER 50S...AS THE
CLOUDS WON/T BE TOO THICK JUST YET AND ANY SHOWER ACTIVITY LOOKS
RATHER SCATTERED IN NATURE AND LIMITED TO JUST SOUTHWESTERN PARTS OF
THE AREA.
A WARM FRONT WILL MOVE ACROSS THE AREA FOR WEDNESDAY. THE BEST CHC
OF SEEING A SHOWER WILL BE FOR SOUTHERN AND WESTERN AREAS. MAX TEMPS
LOOK SIMILAR TO RECENT DAYS WITH 70S FOR MOST PLACES ALTHOUGH IT
WILL START TO FEEL A LITTLE MORE MUGGY THAN RECENT DAYS...WITH
DEWPOINTS STARTING TO CREEP UP IN THE 60S.
THE MODELS AREN/T IN EXACT AGREEMENT REGARDING THE TIMING OF A COLD
FRONT. AT SOME POINT BETWEEN WED NIGHT AND THURSDAY NIGHT...A COLD
FRONT LOOKS TO MOVE ACROSS THE REGION. A WAVE OF LOW PRESSURE MAY
DEVELOP ALONG THIS BOUNDARY...INCREASING THE THREAT FOR SHOWERS AND
THUNDERSTORMS. WITH PWAT VALUES RISING TO NEARLY TWO INCHES...HEAVY
RAINFALL MAY ACCOMPANY ANY OF THE SHOWERS OR THUNDERSTORMS.
DEPENDING ON THE AMOUNT OF INSTABILITY AND TIMING OF THE FRONT ON
THURSDAY...WE MAY HAVE TO WATCH FOR THE POTENTIAL FOR SOME STRONG
TSTMS ON THURSDAY AS WELL...ALTHOUGH THE MAIN THREAT LOOKS TO BE
HEAVY RAINFALL AT THIS POINT. MIN TEMPS ON WED NIGHT AND THURSDAY
NIGHT WILL BE MAINLY IN THE 60S...WITH 70S TO LOW 80S DURING THE DAY
ON THURSDAY.
BEHIND THE FRONT...THE THREAT FOR RAIN SHOULD DIMINISH. SOUTHEASTERN
PARTS OF THE AREA MAY CONTINUE TO SEE A THREAT FOR RAIN SHOWERS ON
FRIDAY DEPENDING ON HOW QUICKLY THE FRONT EXITS THE REGION AND IF IT
STALLS NEARBY. DEWPOINTS WILL DROP SOMEWHAT ON FRIDAY...ALTHOUGH
THE BEST PUSH OF DRY AIR MAY NOT ARRIVE UNTIL LATER IN THE WEEKEND.
MAX TEMPS ON FRIDAY WILL BE NEAR NORMAL...WITH VALLEY TEMPS IN THE
LOW 80S.
IT SHOULD BE DRY FOR FRIDAY NIGHT INTO SATURDAY FOR MOST
PLACES...ALTHOUGH AN UPPER LEVEL DISTURBANCE PASSING TO THE NORTH
MAY ALLOW FOR A SHOWER ACROSS THE ADIRONDACKS. TEMPS WILL CONTINUE
RUN CLOSE TO SEASONAL NORMALS.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
A DISCRETE SURFACE TROUGH AND UPPER LEVEL DISTURBANCE HAS TRIGGERED
SHOWERS AND THUNDERSTORMS ACROSS KGFL AND KALB ALREADY TODAY. THIS
BROKEN LINE HAS PUSHED SOUTH AND EAST OF THESE TAF SITES AND COULD
IMPACT KPSF/KPOU SOON. BEHIND THIS FEATURE STILL SOME WIDELY
SCATTERED SHOWERS AND PERHAPS A THUNDERSTORM SO HAVE ASSIGNED VCSH
TO THE TAFS UNTIL 22Z-00Z (LATEST AT KPSF AND KPOU). THESE SHOWERS
AND STORMS COULD BRIEFLY LOWER CONDITIONS TO MVFR OR PERHAPS
IFR...BUT ONLY FOR A VERY BRIEF TIME.
A GUSTY NORTHWEST BREEZE 10-15 KTS WILL DIMINISH TOWARD DAYBREAK AS
WELL.
OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH THIS EVENING. SCT-BKN
CU BASES GENERALLY AROUND 5000 FEET WILL DISSIPATE TOWARD DARK. WE
ARE CONCERNED ABOUT IFR AT MAINLY KGFL OVERNIGHT BUT PROBABLY JUST
ENOUGH MIXING TO PREVENT IFR FOG AT THE OTHER SITES.
ANY FOG DISSIPATE BY DAYBREAK TOMORROW WITH A GREAT FLYING DAY ON
TAP. THE DAY WILL SEE FEW IF ANY SENSIBLE CLOUDS...UNRESTRICTED
VISIBILITY AND A NORTH TO NORTHWEST WIND 10KTS OR LESS.
OUTLOOK...
MONDAY THROUGH TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY THROUGH THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF
SHRA...TSRA.
&&
.FIRE WEATHER...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON
TODAY AS THE LAST IN A SERIES OF UPPER LEVEL DISTURBANCES MOVES
ACROSS THE REGION.
RH VALUES WILL LOWER TO BETWEEN 45 AND 65 PERCENT ON SUNDAY...AND
RECOVER TO GREATER THAN 90 PERCENT OVERNIGHT.
WEST-NORTHWEST WINDS WILL INCREASE TO 10 TO 20 MPH WITH GUSTS OF
25 TO 30 MPH BY THIS AFTERNOON...AND BECOME LIGHT LATER TONIGHT AS
THE SURFACE RIDGE BUILDS INTO THE REGION.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THROUGH THE PERIOD.
AS ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
OCCUR TODAY AS ANOTHER IN A SERIES OF UPPER LEVEL DISTURBANCES AND
FRONTAL BOUNDARIES CROSS THE REGION. BASIN AVERAGE QPF AMOUNTS FOR
THE REST OF THE WEEKEND WILL BE UNDER A QUARTER OF AN INCH...SO THE
RAINFALL WILL HAVE LITTLE IMPACT ON AREA STREAMS AND RIVERS. DRY
WEATHER IS EXPECTED MONDAY AND TUESDAY. NEXT CHANCE FOR RAINFALL
ARRIVES LATER WEDNESDAY.
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/BGM
NEAR TERM...HWJIV/BGM
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...HWJIV
FIRE WEATHER...FRUGIS
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1020 AM EDT SUN AUG 4 2013
.SYNOPSIS...
A FALL-LIKE AIRMASS HAS BEGUN TO OVERSPREAD THE REGION AND WILL
CONTINUE TO DO SO INTO THE EARLY PORTION OF THIS WEEK. CONDITIONS
WILL BE MORE TYPICAL OF SEPTEMBER THAN AUGUST. DRY WEATHER LIKELY
MONDAY THROUGH WEDNESDAY OF NEXT WEEK THEN BECOMING UNSETTLED
WEDNESDAY NIGHT INTO THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1030 AM UPDATE...
EVALUATING THE HRRR AND OTHER NEAR-TERM MODEL GUIDANCE...
EXPECTING SHOWERS AND ISOLATED THUNDERSTORMS. ACTIVITY MAY BE
DELAYED TILL MID- TO LATE-AFTERNOON BY A DRY AIR INVERSION PER
THE 12Z ALBANY SOUNDING. CONSIDERING WEAK AND THIN INSTABILITY
PROFILES /ALLOWING DRY-AIR ENTRAINMENT INTO ANY UPDRAFT/ COUPLED
WITH A FAIRLY DRY SOUNDING /PWATS LESS THAN AN INCH/ AND AN
INVERTED-V PROFILE AT THE SURFACE...ANY STORMS COULD HAVE THE
POTENTIAL OF PRODUCING A BRIEF HEAVY DOWNPOUR ALONG WITH GUSTY
WINDS. WITH THE WIDELY SCATTERED NATURE OF THE ACTIVITY...HAVE
REMOVED HEAVY RAIN AND GUSTY WIND WORDING FROM THE FORECAST. LOW
CONFIDENCE ON HAIL POTENTIAL.
FEEL ACTIVITY WILL BE CENTERED ON THE REGION WITH BEST MID-LEVEL
LAPSE RATES AND LOW-LEVEL FORCING...PRESENTLY ALONG THE WEAK
TROUGH AXIS OVER UPSTATE NY INTO NORTHERN NEW ENGLAND. LOW-LEVEL
CONVERGENCE POPPING THROUGH A WEAKENING DRY-AIR INVERSION /SEE 12Z
BUFFALO SOUNDING/ AND BOUNDARY LAYER DESTABILIZATION ALREADY
YIELDING SOME SCATTERED ACTIVITY SOUTH AND EAST OF LAKE ONTARIO.
THIS IS COLLOCATED WITH A WEAK WAVE DISTURBANCE AND ENHANCED
ASCENT ALONG THE H5 FLOW /PRESENTLY ENTERING THE ADIRONDACKS/
WHILE SCATTERED SHOWERS MAY DEVELOP AROUND 1 TO 2 PM...AM
EXPECTING THE BULK OF THE ACTIVITY WITHIN THE BETTER REGION OF
LIFT TO PRESS INTO THE NORTHERN AND CENTRAL NEW ENGLAND AROUND 3
TO 4 PM MOVING EAST AND OFFSHORE INTO EVENING. GREATER THREATS OF
HEAVY DOWNPOURS AND GUSTY WINDS MAY REMAIN ALONG AND NORTH OF THE
MASSACHUSETTS TURNPIKE...LOWER CONFIDENCE SOUTH.
TEMPERATURES...DEWPOINTS...AND SKY GRIDS LOOK TO REMAIN ON TRACK.
FEEL THE RAP IS DOING WELL IN HANDLING CLOUD COVER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
SUNDAY...
*** A FALL-LIKE AIRMASS ARRIVES TONIGHT INTO MONDAY ***
NOTABLE COLD AIR ADVECTION TONIGHT...WITH 850 MB TEMPERATURE
REACHING +6C TO +8C BY 12Z MONDAY. LATEST MOS GUIDANCE STILL
FORECASTING TEMPERATURES ABOUT 4-5 DEGREES ABOVE THE RECORD MIN
TEMPERATURES FOR AUGUST 5. WE DO EXPECT WINDS TO DIMINISH BRIEFLY
THIS EVENING...WHICH COULD LEAD TO SEVERAL HOURS OF DECENT
RADIATIONAL COOLING. AT THIS POINT...WE STILL THINK THESE RECORDS
ARE LIKELY OUT OF REACH BUT IT WILL BE CLOSE.
HIGH PRESSURE REACHES THE MID ATLANTIC COAST MONDAY EVENING...
PROVIDING DRY WEATHER TO OUR REGION. BELOW NORMAL TEMPERATURES
CONTINUE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
HIGHLIGHTS...
* MOSTLY DRY...SEASONABLE TO SEASONABLY COOL WEATHER THROUGH TUE
* NEXT CHANCE OF WIDESPREAD RAIN THU
OVERVIEW AND MODEL PREFERENCES...
04/00Z EXTENDED MODEL GUIDANCE SUITE CONTINUES TO SHOW REASONABLY
GOOD SYNOPTIC SCALE AGREEMENT DESPITE THE TRANSITION TO A MORE
MERIDIONAL PATTERN FOR THE LATTER HALF OF THE WEEK. AS USUAL THERE
ARE STILL SOME MORE SUBTLE SUB-SYNOPTIC SCALE ISSUES THAT WILL
NEED TO BE RESOLVED WHICH WILL DICTATE EXACT TIMING/NATURE OF
SENSIBLE WX DETAILS...BUT GIVEN THE BROAD AGREEMENT...PREFER TO
STICK TO A GFS/ECMWF DETERMINISTIC BLEND AS EVEN THEIR RESPECTIVE
ENSEMBLES ARE CLOSELY ON BOARD WITH THE PATTERN.
SRN CONUS RIDGE WHICH WILL FORCE A LONGWAVE TROF DEEPER INTO
CANADA EARLY IN THE WEEK LOSES ITS GRIP IN RESPONSE TO STRONG
CUTOFF WHICH WILL SLIDE S AND E INTO THE GREAT LAKES FROM HUDSON
BAY TOWARD THE LATTER HALF OF THE WEEK. THEREFORE...A DRY AND COOL
PERIOD WILL TRANSITION TO A MORE WET...UNSETTLED AND WARMER
PATTERN LATE IN THE WORK WEEK. HOWEVER...AS THE TROF SLIDES AGAIN
TO THE E...WE MAY SEE ANOTHER ROUND OF DRY WX BY THE COMING
WEEKEND.
DETAILS...
MON NIGHT INTO EARLY WED...
HIGH PRES WILL GRADUALLY CREST OVER THE REGION THROUGH THE
PERIOD. THIS WILL DELIVER DRY CONDITIONS TO SRN NEW ENGLAND. H85
TEMPS BEGIN AROUND +7C THEN INCREASE GRADUALLY TO ABOUT +10C BY
EARLY WED. SO A COOL START WITH HIGHS ONLY BREAKING INTO THE
70S...WITH NIGHTS IN THE 40S TO 50S. TRANSITIONING TO HIGHS NEARER
TO THE LOW 80S BY WED.
WED NIGHT INTO FRI...
CUTOFF LOW AND ASSOCIATED SFC LOW PRES WILL SLIDE INTO SRN CANADA
INITIALLY DRAGGING AN OCCLUDING WARM AND COLD FRONTAL SYSTEM INTO
THE NORTHEAST. INITIALLY IT APPEARS THAT THE SFC WARM FRONT WILL
SLIDE N OF THE REGION ALLOWING SRN NEW ENGLAND INTO THE WARM
SECTOR...HOWEVER...SOME GUIDANCE NOW HAS SECONDARY LOW PRES
DEVELOPMENT IN THE VICINITY OF A POSSIBLE TRIPLE POINT.
THEREFORE...EXPECT THAT RAIN WITH SOME EMBEDDED THUNDER WILL MOVE
IN AHEAD OF THIS FRONT WED NIGHT. WHETHER OR NOT THERE IS MORE
THUNDER ON THU WILL BE DEPENDENT ON THIS SECONDARY LOW PRES
DEVELOPMENT AND IF THE CLOUDS CAN BREAK ENOUGH FOR DIURNAL
DESTABILIZATION. WILL CONTINUE TO CARRY SOME ISOLD THUNDER BUT
THIS WILL HAVE TO BE WATCHED GIVEN THE MITIGATING FACTORS IN
PLACE. WILL HAVE TO WATCH FOR HEAVY RAIN IN EITHER CASE
HOWEVER...GIVEN VERY HIGH PWATS /AROUND 2.0 INCHES/ AND DECENT
DYNAMICS. GUIDANCE DOES HAVE THIS FRONT SLOWING TO A NEAR STALL S
OF NEW ENGLAND FOR FRI...SO MORE CLOUDS AND POSSIBLE WET WX
LINGERS UNTIL HIGH PRES CAN NOSE IN BY FRI EVENING.
THIS COMING WEEKEND...
WILL LEAN A BIT FURTHER AWAY FROM THE MOST RECENT GFS WITH THIS
UPDATE FOR THE WEEKEND...MAINLY DUE TO ITS RECENT INSISTENCE OF
MORE WET WX DESPITE HIGH PRES...NW FLOW AND COLD ADVECTION. WILL
LEAN MORE ON THE DRY ECMWF FOR ANOTHER PERIOD OF DRY WX WITH TEMPS
NEAR NORMAL FOR MID AUGUST.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE CONFIDENCE TODAY
A DRY START...VFR DOMINATES MOST OF THE DAY. MAY BE BRIEF MVFR/IFR
DIP IN VSBYS AND CIGS IN SOME SCT -SHRA/TSRA THIS AFTERNOON. SEA
BREEZE AND INCOMING TROUGH MAY PROVIDE A FOCUS FOR THIS. LOW
CONFIDENCE ON EXACT TIMING OR HOW FAR INLAND SEA BREEZE GETS.
TONIGHT AND MONDAY...ANY LEFTOVER EARLY EVENING SHOWERS/TSTMS
ACROSS EASTERN MA WILL DISSIPATE AND/OR DRIFT OFFSHORE. VFR AND
DRY WEATHER THEN PREVAIL WITH AN INCREASING WNW WIND LATE EVENING.
HIGH CONFIDENCE.
KBOS TERMINAL...HIGH CONFIDENCE IN MAINLY VFR. LOWER CONFIDENCE ON
EXACT TIMING OR IF SEA BREEZE WILL EFFECT TERMINALS. AN AFTERNOON
SHOWER OR THUNDERSTORM MAY ALSO EFFECT THE TERMINAL THIS AFTERNOON.
HIGHEST PROBABILITY FOR SEABREEZE IS FOR 16-18Z START THEN WNW
WINDS SHOULD DOMINATE.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF...MAINLY DUE TO TIMING
AND COVERAGE OF AFTERNOON SHOWER OR THUNDERSTORM POTENTIAL.
OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...
MONDAY NIGHT THROUGH EARLY WEDNESDAY...HIGH CONFIDENCE.
VFR.
WEDNESDAY NIGHT INTO THURSDAY...MODERATE TO HIGH CONFIDENCE.
MVFR/IFR CONDITIONS LIKELY IN SHRA/TSRA/FOG. IMPROVEMENT TO VFR
POSSIBLE AT TIMES.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE.
TODAY...VARIABLE WINDS AHEAD OF THE NEXT FRONT. SCT SHOWERS/TSTMS
NEAR SHORE DURING THIS AFTERNOON...THEN DIMINISHING WITH SUNSET.
TONIGHT...WINDS BECOME NW 15-20 KT WITH HIGHER GUSTS POSSIBLE.
GOOD VSBY.
MONDAY...NW WINDS SLOWLY DIMINISH AND SHIFT MORE WEST DURING THE
AFTERNOON. GOOD VSBY.
OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...
HIGH CONFIDENCE INTO WED...LOWER CONFIDENCE LATE WED AND THU.
MOSTLY QUIET BOATING WEATHER EXPECTED MONDAY NIGHT THROUGH
WEDNESDAY. SEAS START TO INCREASE TO AROUND 5-6 FEET ON THE OUTER
WATERS THURSDAY. MAINLY SOUTHWESTERLY WINDS WILL REMAIN BELOW 25
KTS FOR THE MOST PART THROUGH WED. THE WINDS THEN SHIFT TO THE
SOUTH WEDNESDAY NIGHT AND THURSDAY. WINDS INCREASE...GUSTING TO
AROUND 25 KTS ON THURSDAY. FOG...SHOWERS...AND THUNDERSTORMS WILL
LIMIT VISIBILITIES BEGINNING WEDNESDAY NIGHT.
&&
.CLIMATE...
RECORD LOWS FOR MONDAY AUGUST 5TH...
BOS...54...1972
PVD...51...1972
BDL...47...1972
ORH...48...1929
RECORD LOWS FOR TUESDAY AUGUST 6TH...
BOS...52...1883
PVD...50...1934
BDL...47...1957
ORH...45...1942
&&
.EQUIPMENT...
THE KBOX RADAR HAS BEEN PLACED ON STANDBY PENDING WEATHER FOR
LATER TODAY. FAILURES ON THE AIR CIRCULATION SYSTEMS HAVE RESULTED
IN THE RADAR EQUIPMENT ROOM TO OVERHEAT THEREBY TRIGGERING A RADAR
SHUT DOWN. KEEPING THE EQUIPMENT COOL FOR NOW WILL ALLOW LATER USE
OF THE RADAR FOR TODAY WITH ANY WEATHER. THE RADAR IS EXPECTED TO
REMAIN ON STANDBY DURING ANY QUIET WEATHER FOR AN INDETERMINATE
AMOUNT OF TIME DUE TO THE AFOREMENTIONED FAILURES.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BELK/DOODY
NEAR TERM...SIPPRELL
SHORT TERM...BELK
LONG TERM...DOODY
AVIATION...BELK/DOODY
MARINE...BELK/DOODY
CLIMATE...SIPPRELL
EQUIPMENT...SIPPRELL
AREA FORECAST DISCUSSION
NWS ALBANY NY
945 AM EDT SUN AUG 4 2013
.SYNOPSIS...
A COOLER AIR MASS WILL FILTER INTO THE REGION AS A COLD FRONT MOVES
ACROSS THE REGION TODAY. A FEW SHOWERS AND THUNDERSTORMS ARE
POSSIBLE...BUT MOST OF THE TIME IT SHOULD REMAIN DRY. BELOW NORMAL
TEMPERATURES FOR THIS TIME OF THE YEAR WILL CONTINUE INTO EARLY NEXT
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 AM EDT...SHOWERS HAD DISSIPATED TO THE EAST OF LAKE
ONTARIO. HOWEVER...ANOTHER CLUSTER HAS DEVELOPED IN ONEIDA COUNTY.
CLOUDS WERE BEGINNING TO PERCOLATE AS THE MID LEVELS OF THE
ATMOSPHERE COOL...STEEPENING THE LOW LEVEL LAPSE AND INSTABILITY.
ALSO...H20 WATER VAPOR LOOP INDICATES A SERIES OF DISTURBANCES
HEADING WAY LATER TODAY.
FOR ALL THESE REASONS...WILL KEEP CHANCE SHOWER/THUNDER WITH THE
MENTION OF SMALL HAIL WITH THIS PACKAGE. HOURLY TEMPERATURES WERE
GENERALLY RUNNING 3 DEGREES OR HIGHER THAN THE PREVIOUSLY PROJECTED
HOURLY TEMPS SO WENT AHEAD RE-TOOLED. DID RAISE A FEW TEMPERATURES
2-3 DEGREES...MAINLY IN THE MID HUDSON VALLEY. OTHERWISE LEFT THEM
ALONE.
LOOK FOR HIGH TEMPERATURES 70 TO 75 VALLEY AREAS...UPPER 70S MID
HUDSON VALLEY BUT ONLY IN THE 60S ACROSS THE ELEVATED TERRAIN. A
BREEZE WILL PICK UP FROM THE NORTHWEST 10 TO 15 MPH...GUSTING TO 25
OR MORE IN MORE WIND PRONE AREAS. THE RUC13 SUGGESTS SBCAPES AROUND
1K J/KG WITH WET BULB ZERO HEIGHTS FALLING TO NEAR 8K FEET BY EARLY
AFTERNOON SO THE MENTION OF SMALL HAIL REMAINS IN THE FORECAST.
WITH THE LOSS OF DAYTIME HEATING AND PASSAGE OF THE LAST IN THE
SERIES OF FROPA/S...A CLEARING SKY THIS EVENING. WINDS SHOULD
DECOUPLE AS WE WATCH TEMPERATURES FALL RATHER QUICKLY AS DEWPOINTS
DROP BACK INTO THE 40S. LOWS OVERNIGHT WILL MAINLY BE IN THE 40S
WITH AROUND 50 FOR THE IMMEDIATE CAPITAL REGION AND POINTS SOUTH
ALONG THE HUDSON RIVER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
A LARGE CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE REGION AND
CONTROL OUR WEATHER MONDAY THROUGH MONDAY NIGHT. A MAINLY CLEAR
SKY IS FORECAST BUT IT WILL BE COOL DURING
THIS PERIOD WITH LOWS GENERALLY IN THE 40S TO AROUND 50. HIGHS
IN THE UPPER 60S AND MID 70S...WITH A GRADUAL INCREASE EXPECTED
TUESDAY AFTERNOON.
WARM ADVECTION IS EXPECTED TO UNFOLD UPSTREAM OF THE CWFA WITH
VARIOUS MODELS VARYING ON THE TIMING OF THIS WITH THE LATEST
ECMWF/GGEM THE SLOWEST WITH THE ONSET OF THIS WAA. WE WILL PLACE A
SLIGHT CHANCE POPS FOR PORTIONS OF THE SCHOHARIE VALLEY...WESTERN
MOHAWK VALLEY AND ADIRONDACKS DURING THE AFTERNOON HOURS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WILL START TO SHIFT EAST OF THE AREA ON TUESDAY NIGHT.
THIS WILL ALLOW FOR A MOIST SOUTHERLY FLOW TO RETURN TO THE
REGION...WHICH WILL START TO INCREASE THE CLOUDS AND RETURN THE
THREAT FOR RAINFALL. STILL...MOST AREAS WILL HAVE ANOTHER COOL NIGHT
ON TUES NIGHT WITH MINS IN THE UPPER 40S TO UPPER 50S...AS THE
CLOUDS WON/T BE TOO THICK JUST YET AND ANY SHOWER ACTIVITY LOOKS
RATHER SCATTERED IN NATURE AND LIMITED TO JUST SOUTHWESTERN PARTS OF
THE AREA.
A WARM FRONT WILL MOVE ACROSS THE AREA FOR WEDNESDAY. THE BEST CHC
OF SEEING A SHOWER WILL BE FOR SOUTHERN AND WESTERN AREAS. MAX TEMPS
LOOK SIMILAR TO RECENT DAYS WITH 70S FOR MOST PLACES ALTHOUGH IT
WILL START TO FEEL A LITTLE MORE MUGGY THAN RECENT DAYS...WITH
DEWPOINTS STARTING TO CREEP UP IN THE 60S.
THE MODELS AREN/T IN EXACT AGREEMENT REGARDING THE TIMING OF A COLD
FRONT. AT SOME POINT BETWEEN WED NIGHT AND THURSDAY NIGHT...A COLD
FRONT LOOKS TO MOVE ACROSS THE REGION. A WAVE OF LOW PRESSURE MAY
DEVELOP ALONG THIS BOUNDARY...INCREASING THE THREAT FOR SHOWERS AND
THUNDERSTORMS. WITH PWAT VALUES RISING TO NEARLY TWO INCHES...HEAVY
RAINFALL MAY ACCOMPANY ANY OF THE SHOWERS OR THUNDERSTORMS.
DEPENDING ON THE AMOUNT OF INSTABILITY AND TIMING OF THE FRONT ON
THURSDAY...WE MAY HAVE TO WATCH FOR THE POTENTIAL FOR SOME STRONG
TSTMS ON THURSDAY AS WELL...ALTHOUGH THE MAIN THREAT LOOKS TO BE
HEAVY RAINFALL AT THIS POINT. MIN TEMPS ON WED NIGHT AND THURSDAY
NIGHT WILL BE MAINLY IN THE 60S...WITH 70S TO LOW 80S DURING THE DAY
ON THURSDAY.
BEHIND THE FRONT...THE THREAT FOR RAIN SHOULD DIMINISH. SOUTHEASTERN
PARTS OF THE AREA MAY CONTINUE TO SEE A THREAT FOR RAIN SHOWERS ON
FRIDAY DEPENDING ON HOW QUICKLY THE FRONT EXITS THE REGION AND IF IT
STALLS NEARBY. DEWPOINTS WILL DROP SOMEWHAT ON FRIDAY...ALTHOUGH
THE BEST PUSH OF DRY AIR MAY NOT ARRIVE UNTIL LATER IN THE WEEKEND.
MAX TEMPS ON FRIDAY WILL BE NEAR NORMAL...WITH VALLEY TEMPS IN THE
LOW 80S.
IT SHOULD BE DRY FOR FRIDAY NIGHT INTO SATURDAY FOR MOST
PLACES...ALTHOUGH AN UPPER LEVEL DISTURBANCE PASSING TO THE NORTH
MAY ALLOW FOR A SHOWER ACROSS THE ADIRONDACKS. TEMPS WILL CONTINUE
RUN CLOSE TO SEASONAL NORMALS.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
WHILE THERE WERE SOME BRIEF PERIODS OF IFR FOG AT KGFL/KPOU...THIS
SHOULD DISSIPATE BEFORE THE START OF THE TAF PERIOD. THIS WILL ALLOW
FOR VFR CONDITIONS AT ALL TAF SITES...WITH JUST FEW-SCT LOW AND MID
LEVEL CLOUDS...WITH SCT-BKN HIGH LEVEL CIRROSTRATUS AS WELL.
AS AN UPPER LEVEL DISTURBANCE MOVES NORTH OF THE REGION TODAY...SOME
SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE REGION...MAINLY
FROM THE CAPITAL REGION NORTHWARD AND DURING THE AFTN HOURS.
COVERAGE WILL ONLY BE ISOLD-SCT SO WE WILL HANDLE THIS WITH JUST A
VCSH FOR KALB/KPSF/KGFL. IF ANY LOCATION DOES SEE A SHOWER OR
THUNDERSTORM...A VERY BRIEF PERIOD OF MVFR CONDITIONS COULD
POTENTIALLY OCCUR...ALTHOUGH CONFIDENCE IN THIS OCCURRING AT ANY
SPECIFIC TIME IS TOO LOW TO INCLUDE IN THE TAF AT THIS POINT.
OTHERWISE...SCT-BKN CLOUDS OF 5-7 KFT WITH BE IN PLACE ALONG WITH
SOME MID LEVEL CLOUDS AS WELL AND CONTINUED VFR CONDITIONS. WESTERLY
WINDS WILL PICK UP TO AROUND 10 KTS...WITH A FEW HIGHER GUSTS AT
KALB/KPSF.
WINDS WILL DECREASE WITH THE LOSS OF HEATING BY EVENING...AND AS THE
DISTURBANCE MOVE AWAY...THE THREAT FOR SHOWERS/TSTMS WILL END AS
WELL. ANY BKN CLOUDS WILL BREAK UP...AND SKIES SHOULD GO CLEAR AT
ALL SITES BY MIDNIGHT. SOME BR MAY DEVELOP TOWARDS MIDNIGHT AT KGFL
AND POSSIBLY KPSF AS WELL. THE THREAT WILL BE EVEN HIGHER IF ANY
PRECIP FALLS AT ANY OF THESE TERMINALS DURING THE DAY TODAY. IFR FOG
MAY OCCUR AT KGFL JUST PRIOR TO SUNRISE MONDAY...AND WE WILL HAVE TO
MONITOR KPSF FOR THE POTENTIAL OF THIS AS WELL. WINDS TONIGHT WILL
BE CALM TO LIGHT AT ALL SITES.
OUTLOOK...
MONDAY THROUGH TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY THROUGH THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF
SHRA...TSRA.
&&
.FIRE WEATHER...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON
TODAY AS THE LAST IN A SERIES OF UPPER LEVEL DISTURBANCES MOVES
ACROSS THE REGION.
RH VALUES WILL LOWER TO BETWEEN 45 AND 65 PERCENT ON SUNDAY...AND
RECOVER TO GREATER THAN 90 PERCENT OVERNIGHT.
WEST-NORTHWEST WINDS WILL INCREASE TO 10 TO 20 MPH WITH GUSTS OF
25 TO 30 MPH BY THIS AFTERNOON...AND BECOME LIGHT LATER TONIGHT AS
THE SURFACE RIDGE BUILDS INTO THE REGION.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THROUGH THE PERIOD.
AS ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
OCCUR TODAY AS ANOTHER IN A SERIES OF UPPER LEVEL DISTURBANCES AND
FRONTAL BOUNDARIES CROSS THE REGION. BASIN AVERAGE QPF AMOUNTS FOR
THE REST OF THE WEEKEND WILL BE UNDER A QUARTER OF AN INCH...SO THE
RAINFALL WILL HAVE LITTLE IMPACT ON AREA STREAMS AND RIVERS. DRY
WEATHER IS EXPECTED MONDAY AND TUESDAY. NEXT CHANCE FOR RAINFALL
ARRIVES LATER WEDNESDAY.
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/BGM
NEAR TERM...HWJIV/BGM
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...FRUGIS/JPV
FIRE WEATHER...FRUGIS
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
805 AM EDT SUN AUG 4 2013
.SYNOPSIS...
A COOLER AIR MASS WILL FILTER INTO THE REGION AS A COLD FRONT
MOVES ACROSS THE REGION TODAY. A FEW SHOWERS AND THUNDERSTORMS ARE
EXPECTED...BUT MOST OF THE TIME IT SHOULD REMAIN DRY. BELOW NORMAL
TEMPERATURES FOR THIS TIME OF THE YEAR WILL CONTINUE INTO EARLY
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 615 AM EDT...A FEW SHOWERS HAVE EVOLVED DOWNWIND OF LAKE
ONTARIO EXTENDING INTO THE WESTERN MOHAWK VALLEY. H2O VAPOR LOOP
CLEARLY DEFINES THE LEADING EDGE OF THE APPROACHING SHORT WAVE
TROUGH APPROACHING THE NIAGARA FRONTIER AND EXPERIMENTAL
REFLECTIVITY FORECASTS SUGGEST WIDELY SCATTERED CONVECTION
DEVELOPING LATER THIS MORNING. NEW RUC13 SUGGESTS SBCAPES AROUND 1K
J/KG WITH WET BULB ZERO HEIGHTS FALLING TO NEAR 8K FEET BY EARLY
AFTERNOON SO THE MENTION OF SMALL HAIL REMAINS IN THE FORECAST. THE
MAIN CHANGE WAS TO END POPS/WX A LITTLE SOONER PER TIMING OF THE
UPSTREAM TROUGH AND RUC13 FORECASTS. REMAINDER OF THE FORECAST
REMAINS IN GOOD SHAPE...
REGIONAL RADAR MOSAIC IS RATHER QUIET AS OF 300 AM
EDT...ALTHOUGH...SOME HINTS OF MID LEVEL ECHOES INCREASING
DOWNWIND OF LAKE ONTARIO. THIS IS DUE TO THE COLD ADVECTION MOVING
ACROSS WATER TEMPERATURES INTO THE LOWER 70S AS THOSE DELTA T/S
ARE ON THE INCREASE. SURFACE ANALYSIS REVEALS THE COLD FRONT WAS
JUST NORTH OF LAKE ONTARIO WITH A FEW TROUGHS THAT MESOSCALE
MODELS SUGGEST WILL TRACK THROUGH THE REGION TODAY. SBCAPES ARE
EXPECTED TO BE AROUND 1000 J/KG WITH DROPPING WET BULB ZERO
HEIGHTS AND RATHER STEEP LOW-MID LEVEL LAPSE RATES TO CONTINUE THE
MENTION FOR ISOLATED-SCATTERED CONVECTION WITH SOME SMALL HAIL. IN
FACT...THE LATEST H2O VAPOR LOOP REVEALS THE LEADING EDGE OF THIS
COLDER AIR DIVING SOUTHWARD ACROSS THE UPPER GREAT LAKES SO WE
WILL CONTINUE WITH A SCT-BKN SKY FORECAST AND TEMPERATURES A GOOD
5 DEGREES COOLER THAN YESTERDAY. WEST-NORTHWEST WINDS WILL ALSO BE
ON THE INCREASE WITH A TIGHTENING PRESSURE GRADIENT AND MIXING
LAYER HEIGHTS CLIMBING WELL INTO THE H800 LAYER WHERE 20KTS
RESIDES. HIGHS TODAY GENERALLY IN THE MID 60S TO MID 70S.
WITH THE LOSS OF DAYTIME HEATING AND PASSAGE OF THE LAST IN THE
SERIES OF FROPA/S...CLEARING SKIES THIS EVENING. WINDS SHOULD
DECOUPLE AS WE WATCH TEMPERATURES FALL RATHER QUICKLY AS DEWPOINTS
DROP BACK INTO THE 40S. LOWS OVERNIGHT WILL MAINLY BE IN THE 40S
WITH AROUND 50 FOR THE IMMEDIATE CAPITAL REGION AND POINTS SOUTH
ALONG THE HUDSON RIVER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
A LARGE CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE REGION AND
CONTROL OUR WEATHER MONDAY THROUGH MONDAY NIGHT. A MAINLY CLEAR
SKY IS FORECAST BUT IT WILL BE COOL DURING
THIS PERIOD WITH LOWS GENERALLY IN THE 40S TO AROUND 50. HIGHS
IN THE UPPER 60S AND MID 70S...WITH A GRADUAL INCREASE EXPECTED
TUESDAY AFTERNOON.
WARM ADVECTION IS EXPECTED TO UNFOLD UPSTREAM OF THE CWFA WITH
VARIOUS MODELS VARYING ON THE TIMING OF THIS WITH THE LATEST
ECMWF/GGEM THE SLOWEST WITH THE ONSET OF THIS WAA. WE WILL PLACE A
SLIGHT CHANCE POPS FOR PORTIONS OF THE SCHOHARIE VALLEY...WESTERN
MOHAWK VALLEY AND ADIRONDACKS DURING THE AFTERNOON HOURS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WILL START TO SHIFT EAST OF THE AREA ON TUESDAY NIGHT.
THIS WILL ALLOW FOR A MOIST SOUTHERLY FLOW TO RETURN TO THE
REGION...WHICH WILL START TO INCREASE THE CLOUDS AND RETURN THE
THREAT FOR RAINFALL. STILL...MOST AREAS WILL HAVE ANOTHER COOL NIGHT
ON TUES NIGHT WITH MINS IN THE UPPER 40S TO UPPER 50S...AS THE
CLOUDS WON/T BE TOO THICK JUST YET AND ANY SHOWER ACTIVITY LOOKS
RATHER SCATTERED IN NATURE AND LIMITED TO JUST SOUTHWESTERN PARTS OF
THE AREA.
A WARM FRONT WILL MOVE ACROSS THE AREA FOR WEDNESDAY. THE BEST CHC
OF SEEING A SHOWER WILL BE FOR SOUTHERN AND WESTERN AREAS. MAX TEMPS
LOOK SIMILAR TO RECENT DAYS WITH 70S FOR MOST PLACES ALTHOUGH IT
WILL START TO FEEL A LITTLE MORE MUGGY THAN RECENT DAYS...WITH
DEWPOINTS STARTING TO CREEP UP IN THE 60S.
THE MODELS AREN/T IN EXACT AGREEMENT REGARDING THE TIMING OF A COLD
FRONT. AT SOME POINT BETWEEN WED NIGHT AND THURSDAY NIGHT...A COLD
FRONT LOOKS TO MOVE ACROSS THE REGION. A WAVE OF LOW PRESSURE MAY
DEVELOP ALONG THIS BOUNDARY...INCREASING THE THREAT FOR SHOWERS AND
THUNDERSTORMS. WITH PWAT VALUES RISING TO NEARLY TWO INCHES...HEAVY
RAINFALL MAY ACCOMPANY ANY OF THE SHOWERS OR THUNDERSTORMS.
DEPENDING ON THE AMOUNT OF INSTABILITY AND TIMING OF THE FRONT ON
THURSDAY...WE MAY HAVE TO WATCH FOR THE POTENTIAL FOR SOME STRONG
TSTMS ON THURSDAY AS WELL...ALTHOUGH THE MAIN THREAT LOOKS TO BE
HEAVY RAINFALL AT THIS POINT. MIN TEMPS ON WED NIGHT AND THURSDAY
NIGHT WILL BE MAINLY IN THE 60S...WITH 70S TO LOW 80S DURING THE DAY
ON THURSDAY.
BEHIND THE FRONT...THE THREAT FOR RAIN SHOULD DIMINISH. SOUTHEASTERN
PARTS OF THE AREA MAY CONTINUE TO SEE A THREAT FOR RAIN SHOWERS ON
FRIDAY DEPENDING ON HOW QUICKLY THE FRONT EXITS THE REGION AND IF IT
STALLS NEARBY. DEWPOINTS WILL DROP SOMEWHAT ON FRIDAY...ALTHOUGH
THE BEST PUSH OF DRY AIR MAY NOT ARRIVE UNTIL LATER IN THE WEEKEND.
MAX TEMPS ON FRIDAY WILL BE NEAR NORMAL...WITH VALLEY TEMPS IN THE
LOW 80S.
IT SHOULD BE DRY FOR FRIDAY NIGHT INTO SATURDAY FOR MOST
PLACES...ALTHOUGH AN UPPER LEVEL DISTURBANCE PASSING TO THE NORTH
MAY ALLOW FOR A SHOWER ACROSS THE ADIRONDACKS. TEMPS WILL CONTINUE
RUN CLOSE TO SEASONAL NORMALS.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
WHILE THERE WERE SOME BRIEF PERIODS OF IFR FOG AT KGFL/KPOU...THIS
SHOULD DISSIPATE BEFORE THE START OF THE TAF PERIOD. THIS WILL ALLOW
FOR VFR CONDITIONS AT ALL TAF SITES...WITH JUST FEW-SCT LOW AND MID
LEVEL CLOUDS...WITH SCT-BKN HIGH LEVEL CIRROSTRATUS AS WELL.
AS AN UPPER LEVEL DISTURBANCE MOVES NORTH OF THE REGION TODAY...SOME
SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE REGION...MAINLY
FROM THE CAPITAL REGION NORTHWARD AND DURING THE AFTN HOURS.
COVERAGE WILL ONLY BE ISOLD-SCT SO WE WILL HANDLE THIS WITH JUST A
VCSH FOR KALB/KPSF/KGFL. IF ANY LOCATION DOES SEE A SHOWER OR
THUNDERSTORM...A VERY BRIEF PERIOD OF MVFR CONDITIONS COULD
POTENTIALLY OCCUR...ALTHOUGH CONFIDENCE IN THIS OCCURRING AT ANY
SPECIFIC TIME IS TOO LOW TO INCLUDE IN THE TAF AT THIS POINT.
OTHERWISE...SCT-BKN CLOUDS OF 5-7 KFT WITH BE IN PLACE ALONG WITH
SOME MID LEVEL CLOUDS AS WELL AND CONTINUED VFR CONDITIONS. WESTERLY
WINDS WILL PICK UP TO AROUND 10 KTS...WITH A FEW HIGHER GUSTS AT
KALB/KPSF.
WINDS WILL DECREASE WITH THE LOSS OF HEATING BY EVENING...AND AS THE
DISTURBANCE MOVE AWAY...THE THREAT FOR SHOWERS/TSTMS WILL END AS
WELL. ANY BKN CLOUDS WILL BREAK UP...AND SKIES SHOULD GO CLEAR AT
ALL SITES BY MIDNIGHT. SOME BR MAY DEVELOP TOWARDS MIDNIGHT AT KGFL
AND POSSIBLY KPSF AS WELL. THE THREAT WILL BE EVEN HIGHER IF ANY
PRECIP FALLS AT ANY OF THESE TERMINALS DURING THE DAY TODAY. IFR FOG
MAY OCCUR AT KGFL JUST PRIOR TO SUNRISE MONDAY...AND WE WILL HAVE TO
MONITOR KPSF FOR THE POTENTIAL OF THIS AS WELL. WINDS TONIGHT WILL
BE CALM TO LIGHT AT ALL SITES.
OUTLOOK...
MONDAY THROUGH TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY THROUGH THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF
SHRA...TSRA.
&&
.FIRE WEATHER...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON
TODAY AS THE LAST IN A SERIES OF UPPER LEVEL DISTURBANCES MOVES
ACROSS THE REGION.
RH VALUES WILL LOWER TO BETWEEN 45 AND 65 PERCENT ON SUNDAY...AND
RECOVER TO GREATER THAN 90 PERCENT OVERNIGHT.
WEST-NORTHWEST WINDS WILL INCREASE TO 10 TO 20 MPH WITH GUSTS OF
25 TO 30 MPH BY THIS AFTERNOON...AND BECOME LIGHT LATER TONIGHT AS
THE SURFACE RIDGE BUILDS INTO THE REGION.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THROUGH THE PERIOD.
AS ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
OCCUR TODAY AS ANOTHER IN A SERIES OF UPPER LEVEL DISTURBANCES AND
FRONTAL BOUNDARIES CROSS THE REGION. BASIN AVERAGE QPF AMOUNTS FOR
THE REST OF THE WEEKEND WILL BE UNDER A QUARTER OF AN INCH...SO THE
RAINFALL WILL HAVE LITTLE IMPACT ON AREA STREAMS AND RIVERS. DRY
WEATHER IS EXPECTED MONDAY AND TUESDAY. NEXT CHANCE FOR RAINFALL
ARRIVES LATER WEDNESDAY.
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...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...FRUGIS/JPV
FIRE WEATHER...FRUGIS
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
620 AM EDT SUN AUG 4 2013
.SYNOPSIS...
A COOLER AIR MASS WILL FILTER INTO THE REGION AS A COLD FRONT
MOVES ACROSS THE REGION TODAY. A FEW SHOWERS AND THUNDERSTORMS ARE
EXPECTED...BUT MOST OF THE TIME IT SHOULD REMAIN DRY. BELOW NORMAL
TEMPERATURES FOR THIS TIME OF THE YEAR WILL CONTINUE INTO EARLY
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 615 AM EDT...A FEW SHOWERS HAVE EVOLVED DOWNWIND OF LAKE
ONTARIO EXTENDING INTO THE WESTERN MOHAWK VALLEY. H2O VAPOR LOOP
CLEARLY DEFINES THE LEADING EDGE OF THE APPROACHING SHORT WAVE
TROUGH APPROACHING THE NIAGARA FRONTIER AND EXPERIMENTAL
REFLECTIVITY FORECASTS SUGGEST WIDELY SCATTERED CONVECTION
DEVELOPING LATER THIS MORNING. NEW RUC13 SUGGESTS SBCAPES AROUND 1K
J/KG WITH WET BULB ZERO HEIGHTS FALLING TO NEAR 8K FEET BY EARLY
AFTERNOON SO THE MENTION OF SMALL HAIL REMAINS IN THE FORECAST. THE
MAIN CHANGE WAS TO END POPS/WX A LITTLE SOONER PER TIMING OF THE
UPSTREAM TROUGH AND RUC13 FORECASTS. REMAINDER OF THE FORECAST
REMAINS IN GOOD SHAPE...
REGIONAL RADAR MOSAIC IS RATHER QUIET AS OF 300 AM
EDT...ALTHOUGH...SOME HINTS OF MID LEVEL ECHOES INCREASING
DOWNWIND OF LAKE ONTARIO. THIS IS DUE TO THE COLD ADVECTION MOVING
ACROSS WATER TEMPERATURES INTO THE LOWER 70S AS THOSE DELTA T/S
ARE ON THE INCREASE. SURFACE ANALYSIS REVEALS THE COLD FRONT WAS
JUST NORTH OF LAKE ONTARIO WITH A FEW TROUGHS THAT MESOSCALE
MODELS SUGGEST WILL TRACK THROUGH THE REGION TODAY. SBCAPES ARE
EXPECTED TO BE AROUND 1000 J/KG WITH DROPPING WET BULB ZERO
HEIGHTS AND RATHER STEEP LOW-MID LEVEL LAPSE RATES TO CONTINUE THE
MENTION FOR ISOLATED-SCATTERED CONVECTION WITH SOME SMALL HAIL. IN
FACT...THE LATEST H2O VAPOR LOOP REVEALS THE LEADING EDGE OF THIS
COLDER AIR DIVING SOUTHWARD ACROSS THE UPPER GREAT LAKES SO WE
WILL CONTINUE WITH A SCT-BKN SKY FORECAST AND TEMPERATURES A GOOD
5 DEGREES COOLER THAN YESTERDAY. WEST-NORTHWEST WINDS WILL ALSO BE
ON THE INCREASE WITH A TIGHTENING PRESSURE GRADIENT AND MIXING
LAYER HEIGHTS CLIMBING WELL INTO THE H800 LAYER WHERE 20KTS
RESIDES. HIGHS TODAY GENERALLY IN THE MID 60S TO MID 70S.
WITH THE LOSS OF DAYTIME HEATING AND PASSAGE OF THE LAST IN THE
SERIES OF FROPA/S...CLEARING SKIES THIS EVENING. WINDS SHOULD
DECOUPLE AS WE WATCH TEMPERATURES FALL RATHER QUICKLY AS DEWPOINTS
DROP BACK INTO THE 40S. LOWS OVERNIGHT WILL MAINLY BE IN THE 40S
WITH AROUND 50 FOR THE IMMEDIATE CAPITAL REGION AND POINTS SOUTH
ALONG THE HUDSON RIVER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
A LARGE CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE REGION AND
CONTROL OUR WEATHER MONDAY THROUGH MONDAY NIGHT. A MAINLY CLEAR
SKY IS FORECAST BUT IT WILL BE COOL DURING
THIS PERIOD WITH LOWS GENERALLY IN THE 40S TO AROUND 50. HIGHS
IN THE UPPER 60S AND MID 70S...WITH A GRADUAL INCREASE EXPECTED
TUESDAY AFTERNOON.
WARM ADVECTION IS EXPECTED TO UNFOLD UPSTREAM OF THE CWFA WITH
VARIOUS MODELS VARYING ON THE TIMING OF THIS WITH THE LATEST
ECMWF/GGEM THE SLOWEST WITH THE ONSET OF THIS WAA. WE WILL PLACE A
SLIGHT CHANCE POPS FOR PORTIONS OF THE SCHOHARIE VALLEY...WESTERN
MOHAWK VALLEY AND ADIRONDACKS DURING THE AFTERNOON HOURS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WILL START TO SHIFT EAST OF THE AREA ON TUESDAY NIGHT.
THIS WILL ALLOW FOR A MOIST SOUTHERLY FLOW TO RETURN TO THE
REGION...WHICH WILL START TO INCREASE THE CLOUDS AND RETURN THE
THREAT FOR RAINFALL. STILL...MOST AREAS WILL HAVE ANOTHER COOL NIGHT
ON TUES NIGHT WITH MINS IN THE UPPER 40S TO UPPER 50S...AS THE
CLOUDS WON/T BE TOO THICK JUST YET AND ANY SHOWER ACTIVITY LOOKS
RATHER SCATTERED IN NATURE AND LIMITED TO JUST SOUTHWESTERN PARTS OF
THE AREA.
A WARM FRONT WILL MOVE ACROSS THE AREA FOR WEDNESDAY. THE BEST CHC
OF SEEING A SHOWER WILL BE FOR SOUTHERN AND WESTERN AREAS. MAX TEMPS
LOOK SIMILAR TO RECENT DAYS WITH 70S FOR MOST PLACES ALTHOUGH IT
WILL START TO FEEL A LITTLE MORE MUGGY THAN RECENT DAYS...WITH
DEWPOINTS STARTING TO CREEP UP IN THE 60S.
THE MODELS AREN/T IN EXACT AGREEMENT REGARDING THE TIMING OF A COLD
FRONT. AT SOME POINT BETWEEN WED NIGHT AND THURSDAY NIGHT...A COLD
FRONT LOOKS TO MOVE ACROSS THE REGION. A WAVE OF LOW PRESSURE MAY
DEVELOP ALONG THIS BOUNDARY...INCREASING THE THREAT FOR SHOWERS AND
THUNDERSTORMS. WITH PWAT VALUES RISING TO NEARLY TWO INCHES...HEAVY
RAINFALL MAY ACCOMPANY ANY OF THE SHOWERS OR THUNDERSTORMS.
DEPENDING ON THE AMOUNT OF INSTABILITY AND TIMING OF THE FRONT ON
THURSDAY...WE MAY HAVE TO WATCH FOR THE POTENTIAL FOR SOME STRONG
TSTMS ON THURSDAY AS WELL...ALTHOUGH THE MAIN THREAT LOOKS TO BE
HEAVY RAINFALL AT THIS POINT. MIN TEMPS ON WED NIGHT AND THURSDAY
NIGHT WILL BE MAINLY IN THE 60S...WITH 70S TO LOW 80S DURING THE DAY
ON THURSDAY.
BEHIND THE FRONT...THE THREAT FOR RAIN SHOULD DIMINISH. SOUTHEASTERN
PARTS OF THE AREA MAY CONTINUE TO SEE A THREAT FOR RAIN SHOWERS ON
FRIDAY DEPENDING ON HOW QUICKLY THE FRONT EXITS THE REGION AND IF IT
STALLS NEARBY. DEWPOINTS WILL DROP SOMEWHAT ON FRIDAY...ALTHOUGH
THE BEST PUSH OF DRY AIR MAY NOT ARRIVE UNTIL LATER IN THE WEEKEND.
MAX TEMPS ON FRIDAY WILL BE NEAR NORMAL...WITH VALLEY TEMPS IN THE
LOW 80S.
IT SHOULD BE DRY FOR FRIDAY NIGHT INTO SATURDAY FOR MOST
PLACES...ALTHOUGH AN UPPER LEVEL DISTURBANCE PASSING TO THE NORTH
MAY ALLOW FOR A SHOWER ACROSS THE ADIRONDACKS. TEMPS WILL CONTINUE
RUN CLOSE TO SEASONAL NORMALS.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
WHILE THERE WERE SOME BRIEF PERIODS OF IFR FOG AT KGFL/KPOU...THIS
SHOULD DISSIPATE BEFORE THE START OF THE TAF PERIOD. THIS WILL ALLOW
FOR VFR CONDITIONS AT ALL TAF SITES...WITH JUST FEW-SCT LOW AND MID
LEVEL CLOUDS...WITH SCT-BKN HIGH LEVEL CIRROSTRATUS AS WELL.
AS AN UPPER LEVEL DISTURBANCE MOVES NORTH OF THE REGION TODAY...SOME
SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE REGION...MAINLY
FROM THE CAPITAL REGION NORTHWARD AND DURING THE AFTN HOURS.
COVERAGE WILL ONLY BE ISOLD-SCT SO WE WILL HANDLE THIS WITH JUST A
VCSH FOR KALB/KPSF/KGFL. IF ANY LOCATION DOES SEE A SHOWER OR
THUNDERSTORM...A VERY BRIEF PERIOD OF MVFR CONDITIONS COULD
POTENTIALLY OCCUR...ALTHOUGH CONFIDENCE IN THIS OCCURRING AT ANY
SPECIFIC TIME IS TOO LOW TO INCLUDE IN THE TAF AT THIS POINT.
OTHERWISE...SCT-BKN CLOUDS OF 5-7 KFT WITH BE IN PLACE ALONG WITH
SOME MID LEVEL CLOUDS AS WELL AND CONTINUED VFR CONDITIONS. WESTERLY
WINDS WILL PICK UP TO AROUND 10 KTS...WITH A FEW HIGHER GUSTS AT
KALB/KPSF.
WINDS WILL DECREASE WITH THE LOSS OF HEATING BY EVENING...AND AS THE
DISTURBANCE MOVE AWAY...THE THREAT FOR SHOWERS/TSTMS WILL END AS
WELL. ANY BKN CLOUDS WILL BREAK UP...AND SKIES SHOULD GO CLEAR AT
ALL SITES BY MIDNIGHT. SOME BR MAY DEVELOP TOWARDS MIDNIGHT AT KGFL
AND POSSIBLY KPSF AS WELL. THE THREAT WILL BE EVEN HIGHER IF ANY
PRECIP FALLS AT ANY OF THESE TERMINALS DURING THE DAY TODAY. IFR FOG
MAY OCCUR AT KGFL JUST PRIOR TO SUNRISE MONDAY...AND WE WILL HAVE TO
MONITOR KPSF FOR THE POTENTIAL OF THIS AS WELL. WINDS TONIGHT WILL
BE CALM TO LIGHT AT ALL SITES.
OUTLOOK...
MONDAY THROUGH TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY THROUGH THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF
SHRA...TSRA.
&&
.FIRE WEATHER...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON
TODAY AS THE LAST IN A SERIES OF UPPER LEVEL DISTURBANCES MOVES
ACROSS THE REGION.
RH VALUES WILL LOWER TO BETWEEN 45 AND 65 PERCENT ON SUNDAY...AND
RECOVER TO GREATER THAN 90 PERCENT OVERNIGHT.
WEST-NORTHWEST WINDS WILL INCREASE TO 10 TO 20 MPH WITH GUSTS OF
25 TO 30 MPH BY THIS AFTERNOON...AND BECOME LIGHT LATER TONIGHT AS
THE SURFACE RIDGE BUILDS INTO THE REGION.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THROUGH THE PERIOD.
AS ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
OCCUR TODAY AS ANOTHER IN A SERIES OF UPPER LEVEL DISTURBANCES AND
FRONTAL BOUNDARIES CROSS THE REGION. BASIN AVERAGE QPF AMOUNTS FOR
THE REST OF THE WEEKEND WILL BE UNDER A QUARTER OF AN INCH...SO THE
RAINFALL WILL HAVE LITTLE IMPACT ON AREA STREAMS AND RIVERS. DRY
WEATHER IS EXPECTED MONDAY AND TUESDAY. NEXT CHANCE FOR RAINFALL
ARRIVES LATER WEDNESDAY.
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...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...FRUGIS/JPV
FIRE WEATHER...BGM
HYDROLOGY...BGM
FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS MIAMI FL
815 PM EDT MON AUG 5 2013
.UPDATE...
CONVECTIVE ACTIVITY CONTINUES TO WANE ACROSS THE NORTHWEST
INTERIOR THIS EVENING...DEVOLVING INTO MAINLY MODERATE STRATIFORM
RAIN SHOWERS. LATEST HRRR CONTINUES TO SHOW THE REMAINDER OF THE
LINGERING RAINFALL TO DISSIPATE OVER THE NEXT FEW HOURS AS IT
SLOWLY HEADS TO THE SOUTH. INCREASED POPS THROUGH THE EVENING TO
ACCOUNT FOR THE RATHER LARGE STRATIFORM RAIN SHIELD. THE REMAINDER
OF THE FORECAST LOOKS GOOD AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 755 PM EDT MON AUG 5 2013/
AVIATION...
CONCERNS...EXTENSIVE MID-HI LVL CLDS HAVE HELPED SUPPRESS MOST OF
THE TSTMS AS THEY MOVE SOUTH OF LAKE OKEE INTO THIS EVENING. COULD HAVE
SOME LINGERING SHRA/TSRA REACH MIA & FLL VICINITY NEXT COUPLE OF
HOURS SO PUT VCTS TIL AROUND 03Z. DESPITE THIS, VFR CONDITIONS
SHOULD PREVAIL. LATE NIGHT INTO TUE MORNING, NO SGFNT WX EXPD. SCT
TSTMS DEVELOPING MIDDAY TOMORROW THRU THE EVENING BUT OVERALL (OUTSIDE
ACTIVITY MOVING DIRECTLY OVER AIRPORT WHEN BRIEF IFR CONDITIONS
CANNOT BE RULED OUT) MOSTLY VFR CONDITIONS WITH PERHAPS SOME MVFR
CONDITIONS SHOULD PREVAIL THROUGH THE PERIOD. FOR NOW DECIDED TO
PUT VCTS GROUP IN ALL TAFS FOR THAT PORTION OF THE FCST PERIOD.
SFC WIND...LGT AND VRBL LOOKS GOOD FOR OVERNIGHT ALONG EAST COAST
TERMINALS. THEN ON TUE COULD BRIEFLY GO NE OR E AROUND 16-17Z BFR
SHFTG TO SE 6-8KT AFT 18Z ALONG EAST COAST. LIGHT AND VARIABLE
WINDS AT APF SHOULD TURN ONSHORE AROUND 5-10 KTS BY EARLY PART OF
AFTERNOON.
PREV DISCUSSION... /ISSUED 208 PM EDT MON AUG 5 2013/
SHORT TERM (TONIGHT-TUESDAY NIGHT)...
CURRENT SYNOPTIC ANALYSIS SHOWS STRONG MID LEVEL RIDGE CENTERED OVER
TEXAS WITH ITS RIDGE AXIS STRETCHING TO THE SOUTHEAST ACROSS THE
STRAITS OF FLORIDA. AT THE SURFACE, A TROUGH EXTENDS ACROSS NORTH
CENTRAL FLORIDA INTO THE ATLANTIC WITH A SURFACE RIDGE OVER THE
FLORIDA KEYS. THIS IS CONTINUING THE WESTERLY STEERING FLOW FOR SOUTH
FLORIDA WITH THE BEST CHANCES FOR THUNDERSTORMS OVER THE INTERIOR
AND EAST COAST METRO REGION THROUGH EARLY THIS EVENING. THE
OVERNIGHT HOURS TONIGHT WILL BE MOSTLY TRANQUIL ONCE THE DIURNAL
HEATING CYCLE IS LOST AND THE LOW LEVEL FLOW BECOMES LIGHT AND
VARIABLE.
ON TUESDAY, SOUTH FLORIDA WILL UNDERGO A TRANSITIONAL PERIOD AS A
MID LEVEL INVERTED TROUGH APPROACHES FROM THE EAST. THIS TROUGH IS
CURRENTLY NEAR HISPANIOLA AND HAS BEEN WELL TRACKED BY THE GLOBAL
MODELS. IT WILL MOVE INTO THE EASTERN BAHAMAS ON TUESDAY WHICH WILL
GRADUALLY SHIFT THE MID/UPPER WIND FLOW TO A NORTHEAST DIRECTION. AT
THE SAME TIME, A SURFACE RIDGE WILL BUILD FROM THE CENTRAL GULF OF
MEXICO TO THE SOUTHEAST U.S. VEERING THE LOW LEVEL WIND TO AN EAST
DIRECTION ACROSS OUR REGION. THE FORECAST SOUNDINGS ARE INDICATING
PWAT REMAINING NEAR TWO INCHES SO STORMS WILL TEND TO DEVELOP NEAR
THE EAST COAST AND THEN SLOWLY DRIFT TOWARDS THE WEST INTO THE
EVERGLADES AND SOUTHWEST COAST. THE INVERTED TROUGH WILL MOVE INTO
THE CENTRAL BAHAMAS ON WEDNESDAY WITH A SURFACE RIDGE ACROSS NORTH
FLORIDA. THIS WILL RESULT IN A DEEP EASTERLY FLOW BECOMING
ESTABLISHED ACROSS SOUTH FLORIDA. THIS COULD BRING AN INCREASING
CHANCE OF NOCTURNAL SHOWERS ALONG THE EAST COAST TUESDAY NIGHT INTO
WEDNESDAY MORNING AND A THREAT FOR AFTERNOON THUNDERSTORMS ACROSS
THE INTERIOR AND SOUTHWEST COAST. AT THIS TIME, THE ATMOSPHERIC
INSTABILITY PROFILE DOES NOT CHANGE MUCH WITH PWAT CONTINUING AROUND
TWO INCHES AND WEAK MID LEVEL LAPSE RATES.
LONG TERM (WEDNESDAY-MONDAY)...
LOOKING AHEAD INTO THE EXTENDED PERIOD, THURSDAY APPEARS TO BE
SOMEWHAT UNCERTAIN AS TO THE CHANCE FOR THUNDER. THE INVERTED TROUGH
WILL MOVE ACROSS THE AREA WITH A STRONG DEEP LAYER RIDGE OVER NORTH
FLORIDA. THIS TRANSLATES TO EASTERLY FLOW THROUGH THE ENTIRE
ATMOSPHERE ACROSS SOUTH FLORIDA. IN FACT, THE LATEST 12Z RUN OF THE
GFS IS INDICATING A STEERING FLOW OF 15 TO 20 MPH BY THURSDAY
AFTERNOON AND IF THIS VERIFIES THE CHANCE FOR THUNDER WOULD BE
MINIMAL WITH A MAJORITY OF THE ACTION BEING FAST MOVING SHOWERS.
HOWEVER, THE TROUGH IN PLACE WILL ALSO DESTABILIZE THE MID LEVELS
WITH MODELS ALSO SHOWING SIGNIFICANT COOLING ALOFT. FOR THIS REASON,
DO NOT PLAN TO CHANGE FROM THE CURRENT FORECAST AND WILL WAIT FOR
FUTURE GUIDANCE BEFORE MAKING A DECISION. THE TROUGH WILL CONTINUE
MOVING WEST INTO THE GULF OF MEXICO ON FRIDAY AND INTO THE WEEKEND
WITH THE ATLANTIC RIDGE BUILDING WEST ACROSS THE PENINSULA. THE GFS
IS ALSO SHOWING SIGNIFICANT DRYING ALOFT WITH DEEP EASTERLY FLOW
CONTINUING SO THIS WILL SET THE STAGE FOR SCATTERED SHOWERS/ISOLATED
THUNDER MOSTLY OVER THE INTERIOR AND SOUTHWEST COAST.
MARINE...
THE SOUTHWEST TO WEST WIND WILL GRADUALLY SHIFT TO THE NORTHEAST
AND EAST ON TUESDAY THEN BECOMING EAST ON WEDNESDAY WHILE
INCREASING SPEED TO POSSIBLY 15 KNOTS OVER THE ATLANTIC. THIS WILL
RESULT IN BUILDING SEAS BY MIDWEEK BUT REMAINING BELOW ADVISORY
LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 75 91 77 90 / 40 50 20 30
FORT LAUDERDALE 77 89 80 89 / 30 50 20 30
MIAMI 78 91 78 89 / 30 50 20 30
NAPLES 77 92 76 92 / 20 40 20 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...52/PS
AREA FORECAST DISCUSSION
NWS MIAMI FL
138 AM EDT SUN AUG 4 2013
.AVIATION...CALM WINDS EARLY WILL BECOME W-SW AT AROUND 5 KT THIS
MORNING BEFORE A SEA BREEZE DEVELOPS ALONG THE ATLANTIC COAST WITH
SE WINDS 5-10 KT EXPECTED IN THE AFTERNOON. SCATTERED TSTORMS ARE
EXPECTED DURING THE AFTERNOON, SO CONTINUED WITH VCTS ALL
TERMINALS THEN. THE TSTORMS WILL BE MOST FOCUSED INTERIOR/EAST
COAST LATE IN THE AFTERNOON. BRIEF IFR AND GUSTY WINDS IS
POSSIBLE WITH ANY DIRECT TSTORM IMPACTS. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 745 PM EDT SAT AUG 3 2013/
AVIATION...
ONLY LIGHT TO MODERATE SHRAS REMAIN ACROSS MAINLY THE LAKE
OKEECHOBEE REGION THIS EVENING. LATEST HRRR AND LOCAL SHORT RANGE
MODELS SHOW THIS ACTIVITY DIMINISHING IN COVERAGE OVER THE NEXT
FEW HOURS. THEREFORE DID NOT PREVAIL ANY PRECIPITATION AT ANY
SITE OVERNIGHT...ALTHOUGH COULD NOT RULE OUT AN ISOLATED BRIEF
SHRA AT ANY SITE THROUGH THE REMAINDER OF THIS EVENING.
OTHERWISE...WINDS ARE EXPECTED TO BE NEARLY CALM THROUGH THE NIGHT
AND MAINLY LIGHT OUT OF THE SOUTHWEST DURING THE DAY SUNDAY...WITH
A WEAK EAST COAST SEA BREEZE DEVELOPING BY EARLY AFTERNOON.
PREV DISCUSSION... /ISSUED 725 PM EDT SAT AUG 3 2013/
UPDATE...
THUNDERSTORM ACTIVITY HAS DIMINISHED ACROSS SOUTH FLORIDA,
HOWEVER, THERE STILL ARE SOME SHOWERS IN THE AREA ESPECIALLY
ACROSS THE NORTHERN AREAS. THESE SHOWERS WILL LINGER THROUGH THE
EVENING HOURS BEFORE DIMINISHING. A LIGHT SOUTHWESTERLY STEERING
FLOW WILL CONTINUE THROUGH THE REST OF THE WEEKEND. SCATTERED
SHOWERS AND THUNDERSTORMS WILL REDEVELOP TOMORROW AFTERNOON AND
EVENING ESPECIALLY ACROSS INTERIOR AND EAST COAST SECTIONS. A DEEP
LAYER RIDGE WILL BUILD BACK INTO THE REGION BY THE MIDDLE OF NEXT
WEEK. THIS WILL ALLOW FOR EASTERLY FLOW TO RETURN WHICH WILL FOCUS
THE SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS INTERIOR AND WEST
COAST SECTIONS.
PREV DISCUSSION... /ISSUED 210 PM EDT SAT AUG 3 2013/
SHORT TERM (TONIGHT-MONDAY NIGHT)...
GLOBAL MODELS INITIALIZED QUITE WELL THIS MORNING SHOWING THE WEAK
SURFACE CIRCULATION ASSOCIATED WITH T.D. DORIAN LOCATED OFF THE
NORTHEAST FLORIDA PENINSULA COAST AND A WEAK MID LEVEL TROUGH WHICH
WAS LOCATED JUST EAST OF MLB. A TROUGH BOUNDARY EXTENDS SOUTHWEST OF
THIS FEATURE ACROSS SOUTH FLORIDA AND ALL OF THIS HAD EARLIER HELPED
ENHANCE A LARGE CLUSTER OF CONVECTION ACROSS THE ATLANTIC WATERS
MOSTLY NORTH OF OUR AREA ALONG WITH DIURNAL CYCLE ACTIVITY ACROSS
THE MAINLAND. THE CONVECTION OVER THE WATERS HAS BEGUN TO DIMINISH
AT THIS POINT. THE MODELS ARE ALSO IN GOOD AGREEMENT THAT A DIGGING
MID LEVEL TROUGH INTO THE EASTERN U.S. WILL PUSH A COLD FRONT INTO
THE SOUTHEAST STATES THIS EVENING WHICH WILL PICK UP DORIAN AND LIFT
IT TO THE NORTHEAST BECOMING ABSORBED INTO THE MAIN TROUGH. AT THE
SAME TIME, THE WEAK TROUGH BOUNDARY ACROSS SOUTH FLORIDA WILL ALSO
LIFT TO THE NORTHEAST THIS EVENING SO THE CONVECTION THIS AFTERNOON
DEVELOPING MOSTLY DUE TO THE INFLUENCE OF THE TROUGH AND DIURNAL
HEATING WILL DIMINISH RAPIDLY AFTER SUNSET.
SOUTH FLORIDA WILL THEN ENTER A STAGNANT WEATHER PATTERN FOR THE
REMAINDER OF THIS PERIOD. THE LOW LEVEL RIDGE WILL REMAIN ACROSS THE
FLORIDA STRAITS AS A LARGE MID LEVEL TROUGH MOVES LITTLE ACROSS THE
EASTERN STATES AND A STRONG MID LEVEL RIDGE CENTERED OVER TEXAS WILL
BUILD EAST INTO THE EASTERN GULF OF MEXICO AND THE FLORIDA
PENINSULA. THIS WILL YIELD A WESTERLY STEERING FLOW WITH A
NORTHERLY FLOW IN THE UPPER LEVELS OF THE ATMOSPHERE WHILE
MAINTAINING PWAT OF AROUND TWO INCHES OR SLIGHTLY LESS AND VERY
LITTLE CHANGE TO THE 500MB TEMPERATURES WHICH WILL RUN AROUND -6
CELSIUS. THIS IS RIGHT AT THE NORMAL VALUES FOR EARLY AUGUST. SO
POPS WILL AVERAGE CLOSE TO AUGUST AVERAGES BUT WITH THE HIGHEST
CHANCES OF RAINFALL OVER THE INTERIOR AND EAST COAST METRO AREAS.
FORECAST SOUNDINGS SHOW THE PRIMARY THREAT WILL BE AFTERNOON
THUNDERSTORMS WITH THE CAPABILITY OF PRODUCING SOME ISOLATED STRONG
WIND GUSTS AND THE TYPICAL BRIEF HEAVY DOWNPOURS ALONG WITH FREQUENT
LIGHTNING STRIKES.
LONG TERM (TUESDAY-SATURDAY)...
TUESDAY WILL BE A TRANSITIONAL DAY AS IT APPEARS NOW WITH THE LARGE
SCALE TROUGH OVER THE EAST LIFTING TO THE EAST WHICH WILL ALLOW FOR
A DEEP LAYER RIDGE TO BUILD ACROSS NORTH FLORIDA. SO AS THIS BEGINS
TO OCCUR, THE CONVECTION WILL BE MOSTLY DRIVEN BY SEA BREEZE
BOUNDARIES ON TUESDAY. THEN, AS THE RIDGE BECOMES FIRMLY DEVELOPED
BY WEDNESDAY THROUGH THE REMAINDER OF THE WEEK AND INTO NEXT WEEKEND
THE HIGHEST CHANCES FOR RAIN WILL REVERT TO THE INTERIOR AND
SOUTHWEST COAST. OF COURSE, THERE IS ALWAYS GREATER UNCERTAINTY BY
DAYS 6 AND 7 SO WILL MAINTAIN A BROAD BRUSH CHANCE OF THUNDERSTORMS
FOR ALL AREAS AND WILL ADJUST AS THE FORECAST BECOMES MORE FINE
TUNED.
MARINE...
DUE TO A SOUTHWEST WIND, SEAS WILL BE TRANQUIL THROUGH EARLY NEXT
WEEK OUTSIDE OF STRONGER THUNDERSTORMS WHICH COULD MAKE FOR
HAZARDOUS LOCAL SEAS IN GUSTY WINDS. THE WIND WILL BECOME EAST AT
MOSTLY LESS THAN 15 KNOTS BY LATE TUESDAY THROUGH THE MIDDLE OF
NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 79 92 79 91 / 10 50 20 30
FORT LAUDERDALE 78 89 78 90 / 10 50 20 30
MIAMI 78 91 78 91 / 10 50 20 30
NAPLES 77 90 77 90 / 10 40 10 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1041 PM EDT MON AUG 5 2013
.UPDATE...
NO MAJOR CHANGES TO THE FORECAST THIS EVENING. WILL NEED TO WATCH
TRENDS OVERNIGHT PER LATEST HRRR RUNS WHICH FIRE UP SOME STORMS
OVER CENTRAL GA AROUND 07Z. HARD TO FIND ANY EVIDENCE IN OTHER
SHORT TERM MODELS...BUT WORTH WATCHING NONETHELESS AS THE REMNANT
SEA BREEZE BOUNDARY WORKS INTO THAT REGION. OF MORE INTEREST IS
THE CONVECTION NOTED IN NE GA AFTER 07Z IN BOTH THE HRRR AND RUC.
WILL AGAIN NEED TO WATCH TRENDS AS ONLY THE LATEST RUNS HAVE BEEN
INDICATING THIS.
&&
.PREV DISCUSSION... /ISSUED 827 PM EDT MON AUG 5 2013/
AVIATION...
00Z UPDATE...
STARTING TO SEE CLOUDS TRANSITION TO VFR AT MOST SITES. SHOULD SEE
THAT TREND CONTINUE INTO THE OVERNIGHT UNTIL AROUND 07Z TO 09Z WHEN
CIGS SHOULD DECREASE DOWN TO MVFR AND POSSIBLY IFR FOR A SHORT
STINT. AM CARRYING MVFR AND ON THE CUSP IFR CIGS THROUGH AROUND 15Z
AT MOST SITES BEFORE LIFTING INTO MVFR FOR MOST OF THE DAY. STILL
THINK CONVECTION CHANCES IN THE AFTERNOON WARRANT PROB 30...HOWEVER
TIMING IS STILL TRICKY AS IT WILL LIKELY BE RELATED TO MORNING CIG
BURNOFF RATES. WINDS ARE GOING TO BE A LITTLE TOUGHER AS MODELS ARE
INDICATING A WEAK BOUNDARY ACROSS THE AREA. TO THE NW OF THE
BOUNDARY WINDS ARE EXPECTED TO BE LIGHT OUT OF THE NW. TO THE SE OF
THE BOUNDARY WINDS ARE EXPECTED TO BE OUT OF THE SE. MOST TAF SITES
SHOULD REMAIN ON THE SE SIDE AND THUS AM MAINTAINING A LIGHT...LESS
THAN 5 KTS...SE WIND.
//ATL CONFIDENCE...00Z UPDATE...
MODERATE ON EXACT TIMING OF TRANSITION TO MVFR.
MODERATE ON WIND DIRECTION TUESDAY AFTERNOON
HIGH ALL OTHER ELEMENTS.
30
PREV DISCUSSION... /ISSUED 348 PM EDT MON AUG 5 2013/
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
MODELS CONSISTENT THROUGH THE SHORT TERM WITH LARGE UPPER LEVEL
RIDGE OVER THE SOUTH-CENTRAL U.S. AND LONG-WAVE TROUGH PUSHING EAST
OF THE ATLANTIC COAST. MORE OF A ZONAL FLOW ANTICIPATED ACROSS THE
REGION AS A RESULT...BUT NOT BEFORE SHORTWAVE DROPS INTO THE AREA
TONIGHT AND INTO TUESDAY.
ALREADY SEEING SOME VERY ISOLATED SHOWER DEVELOPMENT THIS
AFTERNOON...MAINLY ALONG THE SOUTHEASTERN EDGE OF THE CWA WITH THE
INFLUENCE OF THE STALLED WEAK SURFACE BOUNDARY. EXPECT THE LOCATION
OF ACTIVITY TO TRANSITION TO THE NORTH AS SHORTWAVE APPROACHES. HAVE
CONTINUED WITH SLIGHT CHANCE TO CHANCE POPS EVERYWHERE THROUGH THE
AFTERNOON...WITH ONLY SLIGHT CHANCE POPS ACROSS THE NORTH AFTER
03-04Z. POPS INCREASE INTO TUESDAY MORNING AND CONTINUE WITH GOOD
CHANCE POPS THROUGH TUESDAY AS SHORTWAVE...COMBINED WITH GOOD
MOISTURE ACROSS THE AREA...RESULTS IN BETTER COVERAGE OF SHOWERS AND
THUNDERSTORMS.
AS FOR TEMPERATURES...HAVE GONE WITH A BLEND OF THE MODEL
GUIDANCE...WHICH HAS WORKED WELL THE LAST SEVERAL DAYS. TUESDAY
HIGHS WILL BE CLOSELY TIED TO PRECIP AND CLOUD COVER...SO ALTHOUGH
FORECAST IS SHOWING MID 80S TO NEAR 90...COULD SEE A FEW DEGREE
ADJUSTMENT BASED ON FUTURE MODEL RUN GUIDANCE.
31
LONG TERM /WEDNESDAY THROUGH MONDAY/...
NO MAJOR CHANGES WERE MADE TO THE EXTENDED PERIOD. LONG RANGE
MODELS CONTINUE TO SHOW A DEEP SOUTHERLY WIND FLOW BECOMING
ESTABLISHED ON WEDNESDAY AND AN OLD FRONTAL BOUNDARY BECOMING
DIFFUSE. THE INCREASING MOISTURE AND INSTABILITY WILL RESULT IN A
MORE SCATTERED TO NUMEROUS COVERAGE OF MAINLY DIURNALLY DRIVEN
CONVECTION THROUGH FRIDAY. MODELS SHOW A FRONTAL BOUNDARY APPROACHING
NORTH GA ON SATURDAY... PUSHING INTO NORTH GA ON SUNDAY... AND
BECOMING NEARLY STATIONARY ACROSS CENTRAL GA ON MONDAY. THIS WOULD
WARRANT SLIGHTLY HIGHER POPS ACROSS AT LEAST NORTH GA ON SATURDAY
AND SUNDAY... THEN ACROSS CENTRAL GA BY MONDAY... AS A DRIER... MORE
STABLE AIR MASS BEGINS TO SPREAD INTO NORTH GA ON MONDAY BEHIND
THE FRONT. ALTHOUGH WIDESPREAD ORGANIZED SEVERE STORMS ARE NOT
EXPECTED WITH THIS OVERALL SYNOPTIC WEATHER PATTERN... AN ISOLATED
PULSE STRONG TO SEVERE STORM CANNOT BE RULED OUT EACH DAY...
ESPECIALLY DURING MAX DAYTIME HEATING.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 84 71 86 / 30 40 30 50
ATLANTA 72 86 72 86 / 20 40 30 50
BLAIRSVILLE 65 83 69 80 / 40 40 40 60
CARTERSVILLE 68 87 72 87 / 30 30 30 50
COLUMBUS 73 92 74 90 / 20 30 20 40
GAINESVILLE 70 83 71 83 / 40 40 30 50
MACON 72 88 71 88 / 20 40 20 40
ROME 67 89 72 88 / 30 30 30 50
PEACHTREE CITY 69 87 71 87 / 20 40 20 50
VIDALIA 73 88 72 91 / 20 40 20 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...30
LONG TERM....DEESE
AVIATION...30
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
407 AM EDT SUN AUG 4 2013
.SYNOPSIS...
THE RETURN OF HIGH PRESSURE WILL BRING MAINLY DRY CONDITIONS FOR
TODAY. MOISTURE WILL INCREASE MONDAY...BRINGING ANOTHER CHANCE OF
SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THIS MORNING...A SHORT WAVE MOVE THROUGH OVERNIGHT BRINGING DRIER
AIR TO THE REGION. A WEAK COLD FRONT WAS IN THE PROCESS OF MOVING
THROUGH THE REGION THIS MORNING AND SHOULD MOVE TO THE SOUTH AND
EAST OF THE FORECAST AREA LATER THIS MORNING. OUR FORECAST REMAINS
DRY THIS MORNING WITH LOWS IN THE LOWER 70S.
TODAY...WEAK HIGH PRESSURE WILL BUILD IN WITH DRY WEATHER EXPECTED.
FORECAST SOUNDINGS INDICATE ATMOSPHERE NOT QUITE AS DRY AND CAPPED
AS IN RECENT DAYS. LFC FAIRLY HIGH. MODERATE INSTABILITIES PROJECTED.
IT APPEARS CONVECTION WILL BE FOCUSED MAINLY ALONG THE WEAKENING
FRONTAL BOUNDARY MAINLY TO THE SOUTH OF THE FORECAST AREA AND ALSO
IN THE COASTAL PLAIN. SOME MODEL DISCREPANCY ON LOCATION...BUT
GENERAL MODEL CONSENSUS FAVORS THE SOUTHERN FA AND COASTAL PLAIN
THIS AFTN/EVE. ANY TSRA THAT FORM COULD PRODUCE STG WND GUSTS DUE
TO DRY AIR ALOFT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
SUNDAY NIGHT...THE FRONT WILL BE SETTLING OVER SOUTHERN GA AS THE
HIGH PRESSURE TRACKS NORTH OF THE FORECAST AREA. THIS WILL PUT THE
AREA UNDER NORTHEASTERLY FLOW. WINDS ALOFT WILL BE NORTHWESTERLY
ALLOWING FOR DOWNSLOPING AND DRYING. WILL CONTINUE POPS LESS THAN
10 PERCENT. OVERNIGHT LOWS IN THE UPPER 60S TO LOWER 70S.
MONDAY AND MONDAY NIGHT...HIGH PRESSURE WILL BEGIN SLIDING EAST OF
THE AREA WITH MOISTURE RETURNING AS FLOW TURNS SOUTHEASTERLY. MID
AND UPPER LEVEL FLOW WILL REMAIN NORTHWESTERLY WHICH WILL KEEP
DRIER AIR IN THE MID AND UPPER LEVELS THROUGH THE DAY LIMITING
CONVECTIVE POTENTIAL. BEST CHANCE OF CONVECTION WILL BE OVER THE
SOUTHERN MIDLANDS AND CSRA WHERE MOISTURE WILL BE A BIT MORE
PLENTIFUL. RAIN CHANCES WILL CONTINUE THROUGH MONDAY NIGHT AS AN
UPPER LEVEL SHORT WAVE MOVES INTO THE AREA. HIGH TEMPERATURES
MONDAY AFTERNOON WILL BE IN THE UPPER 80S TO LOWER 90S WITH LOWS
MONDAY NIGHT IN THE LOWER 70S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
UPPER LEVEL PATTERN WILL BE SLOW TO PROGRESS THROUGH THE LONG TERM
AS A BLOCKING PATTERN REMAINS STRETCHED FROM AK THROUGH THE CANADIAN
PROVINCES. THIS WILL KEEP AN UPPER LEVEL LOW NEAR HUDSON BAY WITH
THE CORRESPONDING TROUGH OVER THE EASTERN US. UPPER RIDGE TO THE
SOUTH AND WEST TRIES TO BUILD TOWARD THE REGION LATE IN THE PERIOD
FRIDAY AND SATURDAY BUT WILL MEET A LOT OF RESISTANCE FROM THE
EASTERN CONUS TROUGH WHICH REMAINS FAIRLY STRONG. THIS WILL KEEP
AN ACTIVE WEATHER PATTERN OVER THE AREA AS A FRONTAL BOUNDARY
STALLS OVER THE REGION WEDNESDAY THROUGH THE END OF THE LONG TERM.
THIS WILL KEEP CHANCES OF SHOWERS AND THUNDERSTORMS IN THE
FORECAST WITH INCREASING CHANCES DURING THE LATTER HALF OF THE
LONG TERM. TEMPERATURES THROUGH THE LONG TERM WILL BE SLIGHTLY
BELOW TO NEAR NORMAL FOR DAYTIME HIGHS WITH OVERNIGHT LOWS NEAR
NORMAL.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
LATEST LAPS SOUNDINGS INDICATE LOW LEVEL MOISTURE HAS BECOME
SHALLOW. SATL INDICATES UPPER LEVEL CLOUDINESS STREAMING ACROSS THE
REGION. NAM BUFKIT INDICATES BOUNDARY LAYER WINDS STAYING UP AROUND
20 KT AND VEERING TO WNW AS A WEAK SURFACE TROUGH COMES THROUGH.
THESE FACTORS...PLUS LACK OF CONVECTION AND RAIN COOLED AIR SATURDAY
ALSO LIMITS FOG THREAT. LATEST HRRR CONFINES ANY STRATUS/FOG
PROJECTIONS TO THE CSRA....WHILE LATEST RAP AND GFS LAMP MORE
OPTIMISTIC. FOR NOW...WILL RESTRICT ANY FOG MENTION TO FOG PRONE
AGS/OGB...KEEPING IT MVFR AT OGB...AND IFR AT AGS.
AFTER ANY LATE NIGHT/EARLY MORNING RESTRICTIONS...VFR EXPECTED.
SURFACE TROUGH WILL PUSH SOUTH TODAY. GFS FORECAST SOUNDINGS
INDICATE ATMOSPHERE NOT QUITE AS DRY AND CAPPED AS IN RECENT DAYS.
IT APPEARS AFTN/EVE CONVECTIVE ACTIVITY WILL BE CONFINED TO A
SURFACE TROUGH MAINLY NEAR THE COASTAL PLAIN...AND POSSIBLY OUR
SOUTHERN FA. CONVECTIVE CHANCES TOO LOW TO INCLUDE TS MENTION IN THE
TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN AFTERNOON
CONVECTION AS WELL AS LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
124 AM EDT SUN AUG 4 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL CROSS THE AREA OVERNIGHT. THE RETURN OF
HIGH PRESSURE WILL BRING MAINLY DRY CONDITIONS FOR SUNDAY.
MOISTURE WILL INCREASE MONDAY...BRINGING ANOTHER CHANCE OF SHOWERS
AND THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
HIGH CLOUDS BLANKETED THE AREA THIS EVENING. AN UPPER TROUGH WAS
MOVING OFF THE COAST PROVIDING NORTHWEST FLOW ALOFT FOR OUR AREA.
A COLD FRONT EXTENDING ACROSS THE CENTRAL APPALACHIANS INTO
WESTERN TN WILL MOVE INTO THE CAROLINAS LATE TONIGHT. NO
SIGNIFICANT SHORT WAVES ARE FORECAST TO AFFECT AREA. GUIDANCE
AGREE ON LITTLE...IF ANY...PRECIP AS THE FRONT WILL ARRIVE AT AN
UNFAVORABLE TIME FOR CONVECTION. OUR FORECAST REMAINS DRY
OVERNIGHT WITH LOWS IN THE LOWER 70S.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH MONDAY NIGHT/...
SUNDAY AND SUNDAY NIGHT...WEAK FRONTAL BOUNDARY WILL HAVE CROSSED
THE AREA BY DAYBREAK WITH WEAK HIGH PRESSURE IN CONTROL OF THE AREA
THROUGH THE DAY. BY EVENING THE FRONT WILL BE SETTLING OVER SOUTHERN
GA AS THE HIGH PRESSURE TRACKS NORTH OF THE FORECAST AREA. THIS WILL
PUT THE AREA UNDER NORTHERLY FLOW SUNDAY WITH NORTHEASTERLY FLOW
SUNDAY NIGHT. WINDS ALOFT WILL BE NORTHWESTERLY ALLOWING FOR
DOWNSLOPING AND DRYING. AS SUCH HAVE REMOVED POPS FOR SUNDAY AND
SUNDAY NIGHT. AFTERNOON HIGH TEMPERATURES WILL BE IN THE LOWER TO
MIDDLE 90S WITH OVERNIGHT LOWS IN THE LOWER 70S.
MONDAY AND MONDAY NIGHT...HIGH PRESSURE WILL BEGIN SLIDING EAST OF
THE AREA WITH MOISTURE RETURNING AS FLOW TURNS SOUTHEASTERLY. MID
AND UPPER LEVEL FLOW WILL REMAIN NORTHWESTERLY WHICH WILL KEEP
DRIER AIR IN THE MID AND UPPER LEVELS THROUGH THE DAY LIMITING
CONVECTIVE POTENTIAL. BEST CHANCE OF CONVECTION WILL BE OVER THE
SOUTHERN MIDLANDS AND CSRA WHERE MOISTURE WILL BE A BIT MORE
PLENTIFUL. RAIN CHANCES WILL CONTINUE THROUGH MONDAY NIGHT AS AN
UPPER LEVEL SHORT WAVE MOVES INTO THE AREA. HIGH TEMPERATURES
MONDAY AFTERNOON WILL BE IN THE UPPER 80S TO LOWER 90S WITH LOWS
MONDAY NIGHT IN THE LOWER 70S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
UPPER LEVEL PATTERN WILL BE SLOW TO PROGRESS THROUGH THE LONG TERM
AS A BLOCKING PATTERN REMAINS STRETCHED FROM AK THROUGH THE CANADIAN
PROVINCES. THIS WILL KEEP AN UPPER LEVEL LOW NEAR HUDSON BAY WITH
THE CORRESPONDING TROUGH OVER THE EASTERN US. THIS WILL KEEP AN
ACTIVE WEATHER PATTERN OVER THE AREA AS A FRONTAL BOUNDARY STALLS
OVER THE REGION WEDNESDAY THROUGH THE END OF THE LONG TERM. THIS
WILL KEEP CHANCES OF SHOWERS AND THUNDERSTORMS IN THE FORECAST
WITH INCREASING CHANCES DURING THE LATTER HALF OF THE LONG TERM.
TEMPERATURES THROUGH THE LONG TERM WILL BE SLIGHTLY BELOW TO NEAR
NORMAL FOR DAYTIME HIGHS WITH OVERNIGHT LOWS NEAR NORMAL.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
LATEST LAPS SOUNDINGS INDICATE LOW LEVEL MOISTURE HAS BECOME
SHALLOW. SATL INDICATES UPPER LEVEL CLOUDINESS STREAMING ACROSS THE
REGION. NAM BUFKIT INDICATES BOUNDARY LAYER WINDS STAYING UP AROUND
20 KT AND VEERING TO WNW AS A WEAK SURFACE TROUGH COMES THROUGH.
THESE FACTORS...PLUS LACK OF CONVECTION AND RAIN COOLED AIR SATURDAY
ALSO LIMITS FOG THREAT. LATEST HRRR CONFINES ANY STRATUS/FOG
PROJECTIONS TO THE CSRA....WHILE LATEST RAP AND GFS LAMP MORE
OPTIMISITIC. FOR NOW...WILL RESTRICT ANY FOG MENTION TO FOG PRONE
AGS/OGB...KEEPING IT MVFR AT OGB...AND IFR AT AGS.
AFTER ANY LATE NIGHT/EARLY MORNING RESTRICTIONS...VFR EXPECTED.
SURFACE TROUGH WILL PUSH SOUTH TODAY. GFS FORECAST SOUNDINGS
INDICATE ATMOSPHERE NOT QUITE AS DRY AND CAPPED AS IN RECENT DAYS.
IT APPEARS AFTN/EVE CONVECTIVE ACTIVITY WILL BE CONFINED TO A
SURFACE TROUGH MAINLY NEAR THE COASTAL PLAIN...AND POSSIBLY OUR
SOUTHERN FA. CONVECTIVE CHANCES TOO LOW TO INCLUDE TS MENTION IN THE
TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN AFTERNOON
CONVECTION AS WELL AS LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1004 PM CDT MON AUG 5 2013
.DISCUSSION...
755 PM CDT
EVENING UPDATE:
MADE TWEAKS TO EVENING GRIDS TO BACK OFF TO ISOLATED SHRA MENTION
FOR APPROXIMATELY NORTHEASTERN HALF OF CWA. SHEARED OUT WAVE AND
MID LEVEL SPEED MAX CONTINUES TO PUSH ACROSS REGION WITH
SIGNIFICANT DRYING NOTED ON WATER VAPOR IN WAKE OF THIS WAVE.
LATEST RAP MESOANALYSIS HAS SHOWN IN INCREASE IN ELEVATED CAPE BUT
00Z DVN RAOB INDICATES THAT THIS IS LIKELY OVERDONE WITH VERY
MARGINAL INSTABILITY AND WEAK MID LEVEL LAPSE RATES ON THE
SOUNDING. WITH THE FORCING FROM THE MIDLEVEL WAVE
OVERHEAD...RETURNS OVER SOUTHWEST WISCONSIN HAVE INCREASED A BIT
IN RECENT SCANS BUT GIVEN THAT INSTABILITY FURTHER DIMINISHES INTO
OUR CWA...THIS ACTIVITY WILL LIKELY ONLY SURVIVE INTO CWA AS
SPOTTY PRIMARILY LIGHT SHOWERS. AN OUTSIDE CHANCE EXISTS FOR AN
ISOLATED T-STORM. THEN WENT WITH A DRY FORECAST AFTER MIDNIGHT FOR
ENTIRE AREA AS FORCING FROM VORT MAX WILL TRANSLATE EAST OF US BY
ABOUT MIDNIGHT.
ATTENTION WILL THEN TURN TO FOG POTENTIAL OVERNIGHT AS AIR MASS
REMAINS MOIST AND WINDS WILL CONTINUE TO DIMINISH. UNCERTAINTY AS
TO WHETHER STRATUS OR FOG IS THE PRIMARY MODE BUT IF BETTER CLEARING
CAN OCCUR...FOG WOULD BECOME MORE FAVORABLE AND EVEN POTENTIALLY
BECOME LOCALLY DENSE. OBS OVER SW WISCONSIN SHOW VSBY BETWEEN 2
AND 4 MILES AND LATEST GUIDANCE STILL SUPPORTS BEST CHANCE FOR
MORE WIDESPREAD FOG TO DEVELOP WELL WEST OF THE LAKEFRONT SO WILL
CONTINUE TO MONITOR OBSERVATIONAL TRENDS THIS EVENING AND MAKE
FURTHER UPDATES IF NEEDED. UPDATED ZONE PRODUCT HAS BEEN SENT.
RC
//PREV DISCUSSION...
312 PM CDT
A PREDOMINANTLY NORTHWESTERLY UPPER FLOW PATTERN WILL BE IN PLACE
THROUGH THE PERIOD WITH OCCASIONAL BUCKLING TO A MORE WESTERLY
DIRECTION OVER THE NEXT FEW DAYS. AS A RESULT...TIMING MODEST PRECIP
CHANCES WILL BE THE MAIN CHALLENGE THROUGH LATE WEEK. WATER VAPOR
IMAGERY SHOWS AN UPPER LOW CENTERED OVER SOUTHWESTERN PORTIONS OF
HUDSON BAY WHILE A LARGE UPPER ANTICYCLONE SPINS OVER TEXAS. BETWEEN
THE TWO...IS A BELT OF NORTHWESTERLY UPPER FLOW STRETCHED FROM THE
NORTHERN U.S. ROCKIES TO THE SOUTHEAST COAST. A CLOSER LOOK AT
SATELLITE SHOWS SEVERAL EMBEDDED SHORTWAVES WITHIN THIS FLOW...WITH
ONE HAVING PASSED OVER THE AREA EARLIER TODAY WITH ANOTHER
APPROACHING LATE THIS AFTERNOON. A LARGER SCALE TROUGH AXIS EXTENDS
FROM THE HUDSON BAY LOW WEST-SOUTHWEST WHERE A SMALLER SCALE
CIRCULATION IS NOTED OVER SOUTHERN ALBERTA. THIS WILL BE KEY IN OUR
WEATHER TUESDAY NIGHT AND WEDNESDAY. FURTHER WEST...ANOTHER UPPER
LOW IS CUTOFF OFF THE NORTHERN CALIFORNIA COAST AND MOVING VERY
LITTLE AS A RESULT. AT THE SURFACE...HIGH PRESSURE IS CENTERED OVER
EASTERN OHIO AND WESTERN PENNSYLVANIA WHILE A LOW IS CENTERED OVER
NORTHERN ONTARIO. A TROUGH AXIS EXTENDS SOUTHWARD FROM THE LOW INTO
EASTERN MINNESOTA AND IOWA.
THIS EVENING THROUGH TUESDAY...A WEAK SHORTWAVE CONTINUES TO CROSS
THE LOCAL AREA WITH A SMALL CLUSTER OF SHRA/TSRA WORKING
EAST-SOUTHEAST ACROSS THE FAR NORTHWEST ILLINOIS BORDER. THIS LOOKS
TO MAINTAIN ITSELF OVER THE NEXT FEW HOURS BUT LITTLE IF ANY LOW
LEVEL INSTABILITY HAS DEVELOPED THANKS TO AN EXTENSIVE...BUT
THINNING...CLOUD SHIELD. WHAT HAS DEVELOPED THOUGH SUGGESTS THAT
THIS CLUSTER WILL WORK SOUTHEAST TOWARD ROCKFORD...ROCHELLE...AND ON
INTO THE WESTERN/SOUTHWESTERN CHICAGO METRO IF IT MAINTAINS. IN
ADDITION...SOME SPOTTY ACTIVITY MAY DEVELOP AROUND THIS CLUSTER
INTO THE EVENING. A FEW STRONGER CORES HAVE POPPED UP FROM TIME TO
TIME IN THE LAST FEW RADAR SCANS WITH THE ACTIVITY BUT WITH SUCH
LIMITED INSTABILITY...THOUGH THERE IS STRONG SHEAR...MORE THAN AN
ISOLATED HAIL CORE OR WIND GUST LOOKS UNLIKELY. CHANCES WILL
DIMINISH THROUGH THE EVENING. THE AFOREMENTIONED TROUGH AXIS/COOL
FRONT MOVING ACROSS MINNESOTA WILL CONTINUE EASTWARD BUT FALL APART
WITH TIME OVERNIGHT. MID LEVEL DRYING IS EXPECTED OVERNIGHT AND WITH
NO COHERENT SOURCE OF FORCING DO NOT SEE MUCH CHANCE FOR PRECIP BY
LATE TONIGHT...IF NOT BEFORE THAT. THE AREA WILL BE BETWEEN SYSTEMS
TUESDAY WHICH SHOULD LEAD TO DRY CONDITIONS THROUGH AT LEAST THE
FIRST PART OF THE DAY BEFORE SMALL CHANCES INCREASE LATER IN THE DAY
AS THE NEXT TROUGH APPROACHES. MORNING CLOUD COVER WILL BE THE WILD
CARD FOR TEMPS AS IT MAY BE EXTENSIVE ALONG WITH SOME MORNING
FOG...BUT A DECREASE IS EXPECTED THROUGH LATE MORNING...WITH SOME
DIURNAL CU AND SOME APPROACHING CIRRUS FOR THE AFTERNOON. H85 TEMPS
WILL BE QUITE WARM RELATIVE TO RECENT DAYS...WITH READINGS AROUND
+16C. THIS COMBINED WITH EXPECTED INCREASE IN SUNSHINE DURING THE
AFTERNOON...AND A MODEST SOUTH-SOUTHWEST WIND SHOULD ALLOW FOR HIGHS
TO WARM INTO THE LOW TO MID 80S...WITH A FEW UPPER 80S POSSIBLE IF
CLOUD COVER IS LESS THAN FORECAST.
TUESDAY NIGHT AND WEDNESDAY...THE UPPER LOW OVER HUDSON BAY WILL
RE-POSITION ITSELF ACROSS EASTERN MANITOBA TUESDAY WITH ANOTHER
TROUGH AXIS ROTATING AROUND IT. THIS WILL PUSH ANOTHER WEAK COOL
FRONT SOUTHEASTWARD ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI
RIVER VALLEY INTO TUESDAY EVENING WHICH WILL THEN CROSS THE LOCAL
AREA EARLY WEDNESDAY. THIS FRONT LOOKS TO BE BETTER ORGANIZED THAN
THE ONE APPROACHING TONIGHT GIVEN THAT THE PARENT SFC LOW WILL BE
FURTHER SOUTH AND BETTER ORGANIZED AS IT CROSSES THE UPPER LAKES AND
CENTRAL ONTARIO. A MOIST AIRMASS WILL BE IN PLACE ACROSS THE AREA
WITH PRECIPITABLE WATER VALUES RUNNING BETWEEN 1.4 AND 1.7 INCHES.
IT APPEARS THAT THERE MAY BE SEVERAL SHORTWAVES THAT CROSS THE AREA
FROM TUESDAY EVENING THROUGH WEDNESDAY MORNING WITH THE MAIN FRONT
NOT PASSING UNTIL WEDNESDAY MORNING. WILL MAINTAIN THE LOW END
LIKELY POPS FROM THE PREVIOUS FORECAST BUT REFINE THE TIMING...WITH
THE BETTER CHANCES STARTING TUESDAY NIGHT. A DRYING TREND IS
EXPECTED WEDNESDAY AFTERNOON AS HIGH PRESSURE DROPS SOUTHEASTWARD
INTO THE AREA SHIFTING WINDS TO THE NORTH AND EAST. HIGHS MAY STILL
BE RATHER MILD WEDNESDAY WITH LOW TO MID 80S...THANKS TO THE UPPER
FLOW BEING ZONAL KEEPING MID LEVEL COOL ADVECTION AT A MINIMUM
THROUGH THE AFTERNOON. HOWEVER...TEMPS NEAR THE LAKESHORE WILL
LIKELY COOL AS WINDS TURN ONSHORE.
THURSDAY THROUGH THE WEEKEND...THE FRONT WILL STALL OUT SOUTH OF THE
AREA INTO EARLY THURSDAY WHILE HIGH PRESSURE MOVES OVERHEAD AND THEN
SHIFTS TO THE EAST. MID LEVEL COOL ADVECTION WILL BE UNDERWAY INTO
THURSDAY LEADING TO HIGHS BACK INTO THE MID TO UPPER 70S...WITH A
FEW 80S SOUTH. COOLEST READINGS WILL BE ALONG THE LAKESHORE AS
ONSHORE FLOW CONTINUES. ONE LAST TROUGH AXIS IS EXPECTED TO ROTATE
AROUND THE UPPER LOW OVER MANITOBA/ONTARIO. GUIDANCE IS LESS CLEAR
IN HOW THIS EVOLVES...WITH SOME SUGGESTION OF A STRONGER WAVE
THANKS TO PHASING OF ENERGY BETWEEN THE MAIN UPPER LOW AND ENERGY
OVERTOPPING A RIDGE ACROSS THE PACIFIC NORTHWEST. THIS WILL HAVE A
BIG IMPACT ON LOCAL POPS LATER THURSDAY AND FRIDAY AS A STRONGER
SYSTEM WOULD FORCE BETTER ORGANIZED SURFACE LOW/INVERTED TROUGH
DEVELOPMENT ACROSS THE MID MISSISSIPPI RIVER VALLEY ALONG THE OLD
FRONTAL BOUNDARY. THE STRONGER THE SURFACE LOW THE FURTHER NORTH THE
OLD BOUNDARY WILL MOVE AND THE GREATER THE CHANCES FOR PRECIP ACROSS
THE CWA. CONFIDENCE IS LOW GIVEN THAT THE UPPER FLOW PATTERN IS
ACTIVE BETWEEN NOW AND THEN AND ITS EVOLUTION MAY BE AFFECTED. AT
THE MOMENT IT APPEARS THAT THE BEST PRECIP CHANCES WILL BE SOUTH OF
THE AREA LATER THURSDAY/FRIDAY...WITH ANOTHER SURFACE HIGH BUILDING
IN INTO SATURDAY. HAVE BETTER CONFIDENCE IN THE MAIN UPPER LOW
MOVING EASTWARD WHICH WILL ALLOW RIDGING TO BUILD WEST AND A MORE
PRONOUNCED NORTHWEST FLOW ALOFT OF THE LOCAL AREA FOR THE WEEKEND.
THIS WILL LIKELY RESULT IN HIGHS THAT CONTINUE TO BE SEVERAL DEGREES
BELOW NORMAL. EXPECT DRY CONDITIONS SATURDAY BEFORE A SLIGHT INFLUX
IN MOISTURE ARRIVES SUNDAY/MONDAY WITH THE UPPER FLOW LOOKING TO
BECOME MORE ACTIVE. WILL LEAVE SUNDAY DRY FOR NOW.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* ISOLD/SCT SHRA THROUGH LATE EVENING. MAINLY VFR...THOUGH PATCHY
MVFR CIGS PSBL IN SHRA. ISOLD TS NOT OUT OF QUESTION BUT IS NOT
LIKELY. PRECIP MOST LIKELY NORTH OF ORD/MDW.
* POTENTIAL FOR MVFR CIG/VIS CONDITIONS TO GRADUALLY DEVELOP AFTER
SUNSET TONIGHT IN MOIST LOW LEVEL ENVIRONMENT. APPEARS THERE
WILL BE A PRELIMINARY BRIEF ~2 HR PERIOD OF 2500 FT LATE
EVENING...THEN LIKELY LONGER DURATION/LOWER CONDITIONS AFTER ANY
LATE CLEARING. IF STRATUS FOG DO DEVELOP OVERNIGHT IMPROVEMENT
MAY BE SLOW TUESDAY MORNING.
* CHANCE OF TSRA INCREASES LATER TUESDAY NIGHT.
RATZER
//DISCUSSION...UPDATED 00Z...
ISOLATED/SCATTERED SHOWERS CONTINUE TO SLIDE SOUTHEAST ACROSS
PARTS OF SOUTHERN WI/NORTHERN IL AND NORTHWEST IN EARLY THIS
EVENING IN ASSOCIATION WITH AN ELEVATED WARM FRONT AND A PASSING
UPPER LEVEL DISTURBANCE. EXTRAPOLATION PER SATELLITE IMAGERY
INDICATES THIS DISTURBANCE WILL TRACK OFF TO THE SOUTHEAST OF THE
AREA LATE THIS EVENING...WITH WEAK BUT PERSISTENT MOIST ASCENT
LIKELY CONTINUING TO PRODUCE SPOTTY SHRA UNTIL IT PASSES. FORECAST
SOUNDINGS CONTINUE TO DEPICT A SLIGHT INCREASE IN ELEVATED
INSTABILITY ACROSS THE AREA THIS EVENING...THOUGH SUSPECT ANY TSRA
WILL REMAIN ISOLATED WITH VERY LOW PROBABILITY AT ANY PARTICULAR
TERMINAL SITE.
WEAK FRONTAL BOUNDARY ACROSS MN/IA WILL THEN GRADUALLY DRIFT TO
THE EAST INTO WI/IL OVERNIGHT...BEFORE STALLING AND WASHING OUT.
POOLED MOISTURE NEAR THIS WEAKENING BOUNDARY WILL RESULT IN
INCREASINGLY HUMID CONDITIONS LATER TONIGHT INTO TUESDAY. FAIRLY
EXTENSIVE AREA OF MVFR/IFR CIGS ACROSS IA AND WI CURRENTLY...AND
MODEL GUIDANCE DEPICTS A GRADUAL DETERIORATION OF CIG/VIS CONDITIONS
INTO MVFR ACROSS NORTHERN IL AND NORTHWEST IN TERMINALS OVERNIGHT.
AM A LITTLE RELUCTANT TO FORECAST CONDITIONS TOO LOW AT THIS POINT
WITH RAIN HAVING BEEN MORE SPOTTY THAN MANY MODEL FORECASTS
INDICATED...THOUGH DEVELOPMENT OF MVFR CIG/VIS CONDITIONS DOES
SEEM REASONABLE GIVEN PERSISTENT ALBEIT LIGHT WEST-SOUTHWEST FLOW
IN LOW LEVELS AND AFOREMENTIONED MOISTURE POOLING/HUMID BOUNDARY
LAYER AND SCATTERING OF HIGHER CLOUD LAYERS OVERNIGHT IN WAKE OF
AFOREMENTIONED DISTURBANCE. WITH FRONT BECOMING LESS DISCERNIBLE
WITH TIME...AND LITTLE DYNAMIC PUSH FOR CLEARING...IT MAY TAKE
SEVERAL HOURS TUESDAY MORNING FOR IMPROVEMENT BACK TO VFR.
WINDS HAVE BACKED SLIGHTLY TO SOUTH-SOUTHEAST LATE THIS
AFTERNOON/EARLY EVENING...THOUGH THEY SHOULD EVENTUALLY SETTLE
BACK TO MORE OF A SOUTH-SOUTHWEST DIRECTION OVERNIGHT AND TUESDAY
AHEAD OF STALLING FRONTAL BOUNDARY. SPEEDS EXPECTED TO BE
GENERALLY 10 KT OR LESS TONIGHT...AROUND 10 KT WITH PERHAPS A FEW
GUSTS NEAR 15 KT BY TUESDAY AFTERNOON.
NEXT UPPER DISTURBANCE OF SUBSTANCE APPROACHES THE AREA TUESDAY
NIGHT...WHICH LOOKS TO GRADUALLY INCREASE POTENTIAL FOR SHRA/TSRA
BEYOND 00Z WED.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH CONFIDENCE IN SHRA TRENDS THIS EVENING.
* MEDIUM CONFIDENCE IN MVFR CIG/VIS CONDITIONS DEVELOPING LATER
THIS EVENING/OVERNIGHT AND LINGERING INTO TUESDAY MORNING.
* LOW CONFIDENCE IN CIG HEIGHT TRENDS TUESDAY...ESPECIALLY
MORNING.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...CHANCE TSRA MAINLY MORNING. OTHERWISE VFR.
THURSDAY THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY SOUTH OF
CHICAGO THURSDAY NIGHT.
RATZER
&&
.MARINE...
240 PM...A BROAD WEAK TROUGH EXTENDING ACROSS THE PLAINS FROM A
SLIGHTLY STRONGER LOW OVER ONTARIO WILL SLOWLY MOVE EAST ACROSS
THE WESTERN LAKES WEDNESDAY...WITH THE LOW OVER ONTARIO SLOWLY
MOVING EAST THROUGH MID WEEK. AHEAD OF THIS TROUGH...SOUTHERLY
WINDS HAVE INCREASED TO 10-20 KT AND FORECAST SOUNDINGS SUGGEST
THE POTENTIAL FOR SOME WINDS INTO THE 15-25 KT RANGE THIS EVENING
BEFORE SLOWLY DIMINISHING OVERNIGHT. ONCE THE TROUGH/COLD FRONT
MOVES ACROSS THE LAKE MIDDAY WEDNESDAY...WINDS WILL SHIFT
NORTHERLY WITH A PERIOD OF 10-20 KTS POSSIBLE BUT APPEARS THAT
WOULD BE SHORT LIVED AS HIGH PRESSURE SPREADS ACROSS THE LAKES
REGION WEDNESDAY NIGHT INTO THURSDAY. THE LOW OVER ONTARIO FINALLY
SHIFTS EAST INTO QUEBEC ON FRIDAY...WITH A WEAK COLD FRONT MOVING
ACROSS THE WESTERN LAKES FRIDAY NIGHT SHIFTING WINDS BACK
NORTHERLY INTO SATURDAY WITH ANOTHER HIGH MOVING ACROSS THE LAKES
SATURDAY NIGHT INTO SUNDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
758 PM CDT MON AUG 5 2013
.DISCUSSION...
755 PM CDT
EVENING UPDATE:
MADE TWEAKS TO EVENING GRIDS TO BACK OFF TO ISOLATED SHRA MENTION
FOR APPROXIMATELY NORTHEASTERN HALF OF CWA. SHEARED OUT WAVE AND
MID LEVEL SPEED MAX CONTINUES TO PUSH ACROSS REGION WITH
SIGNIFICANT DRYING NOTED ON WATER VAPOR IN WAKE OF THIS WAVE.
LATEST RAP MESOANALYSIS HAS SHOWN IN INCREASE IN ELEVATED CAPE BUT
00Z DVN RAOB INDICATES THAT THIS IS LIKELY OVERDONE WITH VERY
MARGINAL INSTABILITY AND WEAK MID LEVEL LAPSE RATES ON THE
SOUNDING. WITH THE FORCING FROM THE MIDLEVEL WAVE
OVERHEAD...RETURNS OVER SOUTHWEST WISCONSIN HAVE INCREASED A BIT
IN RECENT SCANS BUT GIVEN THAT INSTABILITY FURTHER DIMINISHES INTO
OUR CWA...THIS ACTIVITY WILL LIKELY ONLY SURVIVE INTO CWA AS
SPOTTY PRIMARILY LIGHT SHOWERS. AN OUTSIDE CHANCE EXISTS FOR AN
ISOLATED T-STORM. THEN WENT WITH A DRY FORECAST AFTER MIDNIGHT FOR
ENTIRE AREA AS FORCING FROM VORT MAX WILL TRANSLATE EAST OF US BY
ABOUT MIDNIGHT.
ATTENTION WILL THEN TURN TO FOG POTENTIAL OVERNIGHT AS AIR MASS
REMAINS MOIST AND WINDS WILL CONTINUE TO DIMINISH. UNCERTAINTY AS
TO WHETHER STRATUS OR FOG IS THE PRIMARY MODE BUT IF BETTER CLEARING
CAN OCCUR...FOG WOULD BECOME MORE FAVORABLE AND EVEN POTENTIALLY
BECOME LOCALLY DENSE. OBS OVER SW WISCONSIN SHOW VSBY BETWEEN 2
AND 4 MILES AND LATEST GUIDANCE STILL SUPPORTS BEST CHANCE FOR
MORE WIDESPREAD FOG TO DEVELOP WELL WEST OF THE LAKEFRONT SO WILL
CONTINUE TO MONITOR OBSERVATIONAL TRENDS THIS EVENING AND MAKE
FURTHER UPDATES IF NEEDED. UPDATED ZONE PRODUCT HAS BEEN SENT.
RC
&&
.PREV DISCUSSION...
312 PM CDT
A PREDOMINANTLY NORTHWESTERLY UPPER FLOW PATTERN WILL BE IN PLACE
THROUGH THE PERIOD WITH OCCASIONAL BUCKLING TO A MORE WESTERLY
DIRECTION OVER THE NEXT FEW DAYS. AS A RESULT...TIMING MODEST PRECIP
CHANCES WILL BE THE MAIN CHALLENGE THROUGH LATE WEEK. WATER VAPOR
IMAGERY SHOWS AN UPPER LOW CENTERED OVER SOUTHWESTERN PORTIONS OF
HUDSON BAY WHILE A LARGE UPPER ANTICYCLONE SPINS OVER TEXAS. BETWEEN
THE TWO...IS A BELT OF NORTHWESTERLY UPPER FLOW STRETCHED FROM THE
NORTHERN U.S. ROCKIES TO THE SOUTHEAST COAST. A CLOSER LOOK AT
SATELLITE SHOWS SEVERAL EMBEDDED SHORTWAVES WITHIN THIS FLOW...WITH
ONE HAVING PASSED OVER THE AREA EARLIER TODAY WITH ANOTHER
APPROACHING LATE THIS AFTERNOON. A LARGER SCALE TROUGH AXIS EXTENDS
FROM THE HUDSON BAY LOW WEST-SOUTHWEST WHERE A SMALLER SCALE
CIRCULATION IS NOTED OVER SOUTHERN ALBERTA. THIS WILL BE KEY IN OUR
WEATHER TUESDAY NIGHT AND WEDNESDAY. FURTHER WEST...ANOTHER UPPER
LOW IS CUTOFF OFF THE NORTHERN CALIFORNIA COAST AND MOVING VERY
LITTLE AS A RESULT. AT THE SURFACE...HIGH PRESSURE IS CENTERED OVER
EASTERN OHIO AND WESTERN PENNSYLVANIA WHILE A LOW IS CENTERED OVER
NORTHERN ONTARIO. A TROUGH AXIS EXTENDS SOUTHWARD FROM THE LOW INTO
EASTERN MINNESOTA AND IOWA.
THIS EVENING THROUGH TUESDAY...A WEAK SHORTWAVE CONTINUES TO CROSS
THE LOCAL AREA WITH A SMALL CLUSTER OF SHRA/TSRA WORKING
EAST-SOUTHEAST ACROSS THE FAR NORTHWEST ILLINOIS BORDER. THIS LOOKS
TO MAINTAIN ITSELF OVER THE NEXT FEW HOURS BUT LITTLE IF ANY LOW
LEVEL INSTABILITY HAS DEVELOPED THANKS TO AN EXTENSIVE...BUT
THINNING...CLOUD SHIELD. WHAT HAS DEVELOPED THOUGH SUGGESTS THAT
THIS CLUSTER WILL WORK SOUTHEAST TOWARD ROCKFORD...ROCHELLE...AND ON
INTO THE WESTERN/SOUTHWESTERN CHICAGO METRO IF IT MAINTAINS. IN
ADDITION...SOME SPOTTY ACTIVITY MAY DEVELOP AROUND THIS CLUSTER
INTO THE EVENING. A FEW STRONGER CORES HAVE POPPED UP FROM TIME TO
TIME IN THE LAST FEW RADAR SCANS WITH THE ACTIVITY BUT WITH SUCH
LIMITED INSTABILITY...THOUGH THERE IS STRONG SHEAR...MORE THAN AN
ISOLATED HAIL CORE OR WIND GUST LOOKS UNLIKELY. CHANCES WILL
DIMINISH THROUGH THE EVENING. THE AFOREMENTIONED TROUGH AXIS/COOL
FRONT MOVING ACROSS MINNESOTA WILL CONTINUE EASTWARD BUT FALL APART
WITH TIME OVERNIGHT. MID LEVEL DRYING IS EXPECTED OVERNIGHT AND WITH
NO COHERENT SOURCE OF FORCING DO NOT SEE MUCH CHANCE FOR PRECIP BY
LATE TONIGHT...IF NOT BEFORE THAT. THE AREA WILL BE BETWEEN SYSTEMS
TUESDAY WHICH SHOULD LEAD TO DRY CONDITIONS THROUGH AT LEAST THE
FIRST PART OF THE DAY BEFORE SMALL CHANCES INCREASE LATER IN THE DAY
AS THE NEXT TROUGH APPROACHES. MORNING CLOUD COVER WILL BE THE WILD
CARD FOR TEMPS AS IT MAY BE EXTENSIVE ALONG WITH SOME MORNING
FOG...BUT A DECREASE IS EXPECTED THROUGH LATE MORNING...WITH SOME
DIURNAL CU AND SOME APPROACHING CIRRUS FOR THE AFTERNOON. H85 TEMPS
WILL BE QUITE WARM RELATIVE TO RECENT DAYS...WITH READINGS AROUND
+16C. THIS COMBINED WITH EXPECTED INCREASE IN SUNSHINE DURING THE
AFTERNOON...AND A MODEST SOUTH-SOUTHWEST WIND SHOULD ALLOW FOR HIGHS
TO WARM INTO THE LOW TO MID 80S...WITH A FEW UPPER 80S POSSIBLE IF
CLOUD COVER IS LESS THAN FORECAST.
TUESDAY NIGHT AND WEDNESDAY...THE UPPER LOW OVER HUDSON BAY WILL
RE-POSITION ITSELF ACROSS EASTERN MANITOBA TUESDAY WITH ANOTHER
TROUGH AXIS ROTATING AROUND IT. THIS WILL PUSH ANOTHER WEAK COOL
FRONT SOUTHEASTWARD ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI
RIVER VALLEY INTO TUESDAY EVENING WHICH WILL THEN CROSS THE LOCAL
AREA EARLY WEDNESDAY. THIS FRONT LOOKS TO BE BETTER ORGANIZED THAN
THE ONE APPROACHING TONIGHT GIVEN THAT THE PARENT SFC LOW WILL BE
FURTHER SOUTH AND BETTER ORGANIZED AS IT CROSSES THE UPPER LAKES AND
CENTRAL ONTARIO. A MOIST AIRMASS WILL BE IN PLACE ACROSS THE AREA
WITH PRECIPITABLE WATER VALUES RUNNING BETWEEN 1.4 AND 1.7 INCHES.
IT APPEARS THAT THERE MAY BE SEVERAL SHORTWAVES THAT CROSS THE AREA
FROM TUESDAY EVENING THROUGH WEDNESDAY MORNING WITH THE MAIN FRONT
NOT PASSING UNTIL WEDNESDAY MORNING. WILL MAINTAIN THE LOW END
LIKELY POPS FROM THE PREVIOUS FORECAST BUT REFINE THE TIMING...WITH
THE BETTER CHANCES STARTING TUESDAY NIGHT. A DRYING TREND IS
EXPECTED WEDNESDAY AFTERNOON AS HIGH PRESSURE DROPS SOUTHEASTWARD
INTO THE AREA SHIFTING WINDS TO THE NORTH AND EAST. HIGHS MAY STILL
BE RATHER MILD WEDNESDAY WITH LOW TO MID 80S...THANKS TO THE UPPER
FLOW BEING ZONAL KEEPING MID LEVEL COOL ADVECTION AT A MINIMUM
THROUGH THE AFTERNOON. HOWEVER...TEMPS NEAR THE LAKESHORE WILL
LIKELY COOL AS WINDS TURN ONSHORE.
THURSDAY THROUGH THE WEEKEND...THE FRONT WILL STALL OUT SOUTH OF THE
AREA INTO EARLY THURSDAY WHILE HIGH PRESSURE MOVES OVERHEAD AND THEN
SHIFTS TO THE EAST. MID LEVEL COOL ADVECTION WILL BE UNDERWAY INTO
THURSDAY LEADING TO HIGHS BACK INTO THE MID TO UPPER 70S...WITH A
FEW 80S SOUTH. COOLEST READINGS WILL BE ALONG THE LAKESHORE AS
ONSHORE FLOW CONTINUES. ONE LAST TROUGH AXIS IS EXPECTED TO ROTATE
AROUND THE UPPER LOW OVER MANITOBA/ONTARIO. GUIDANCE IS LESS CLEAR
IN HOW THIS EVOLVES...WITH SOME SUGGESTION OF A STRONGER WAVE
THANKS TO PHASING OF ENERGY BETWEEN THE MAIN UPPER LOW AND ENERGY
OVERTOPPING A RIDGE ACROSS THE PACIFIC NORTHWEST. THIS WILL HAVE A
BIG IMPACT ON LOCAL POPS LATER THURSDAY AND FRIDAY AS A STRONGER
SYSTEM WOULD FORCE BETTER ORGANIZED SURFACE LOW/INVERTED TROUGH
DEVELOPMENT ACROSS THE MID MISSISSIPPI RIVER VALLEY ALONG THE OLD
FRONTAL BOUNDARY. THE STRONGER THE SURFACE LOW THE FURTHER NORTH THE
OLD BOUNDARY WILL MOVE AND THE GREATER THE CHANCES FOR PRECIP ACROSS
THE CWA. CONFIDENCE IS LOW GIVEN THAT THE UPPER FLOW PATTERN IS
ACTIVE BETWEEN NOW AND THEN AND ITS EVOLUTION MAY BE AFFECTED. AT
THE MOMENT IT APPEARS THAT THE BEST PRECIP CHANCES WILL BE SOUTH OF
THE AREA LATER THURSDAY/FRIDAY...WITH ANOTHER SURFACE HIGH BUILDING
IN INTO SATURDAY. HAVE BETTER CONFIDENCE IN THE MAIN UPPER LOW
MOVING EASTWARD WHICH WILL ALLOW RIDGING TO BUILD WEST AND A MORE
PRONOUNCED NORTHWEST FLOW ALOFT OF THE LOCAL AREA FOR THE WEEKEND.
THIS WILL LIKELY RESULT IN HIGHS THAT CONTINUE TO BE SEVERAL DEGREES
BELOW NORMAL. EXPECT DRY CONDITIONS SATURDAY BEFORE A SLIGHT INFLUX
IN MOISTURE ARRIVES SUNDAY/MONDAY WITH THE UPPER FLOW LOOKING TO
BECOME MORE ACTIVE. WILL LEAVE SUNDAY DRY FOR NOW.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* ISOLD/SCT SHRA EARLY THIS EVENING. MAINLY VFR...THOUGH PATCHY
MVFR CIGS PSBL IN SHRA. ISOLD TS NOT OUT OF QUESTION BUT IS NOT
LIKELY.
* POTENTIAL FOR MVFR CIG/VIS CONDITIONS TO GRADUALLY DEVELOP AFTER
SUNSET TONIGHT IN MOIST LOW LEVEL ENVIRONMENT. IF STRATUS FOG DO
DEVELOP OVERNIGHT IMPROVEMENT MAY BE SLOW TUESDAY MORNING.
* CHANCE OF TSRA INCREASES LATER TUESDAY NIGHT.
RATZER
//DISCUSSION...UPDATED 00Z...
ISOLATED/SCATTERED SHOWERS CONTINUE TO SLIDE SOUTHEAST ACROSS
PARTS OF SOUTHERN WI/NORTHERN IL AND NORTHWEST IN EARLY THIS
EVENING IN ASSOCIATION WITH AN ELEVATED WARM FRONT AND A PASSING
UPPER LEVEL DISTURBANCE. EXTRAPOLATION PER SATELLITE IMAGERY
INDICATES THIS DISTURBANCE WILL TRACK OFF TO THE SOUTHEAST OF THE
AREA LATE THIS EVENING...WITH WEAK BUT PERSISTENT MOIST ASCENT
LIKELY CONTINUING TO PRODUCE SPOTTY SHRA UNTIL IT PASSES. FORECAST
SOUNDINGS CONTINUE TO DEPICT A SLIGHT INCREASE IN ELEVATED
INSTABILITY ACROSS THE AREA THIS EVENING...THOUGH SUSPECT ANY TSRA
WILL REMAIN ISOLATED WITH VERY LOW PROBABILITY AT ANY PARTICULAR
TERMINAL SITE.
WEAK FRONTAL BOUNDARY ACROSS MN/IA WILL THEN GRADUALLY DRIFT TO
THE EAST INTO WI/IL OVERNIGHT...BEFORE STALLING AND WASHING OUT.
POOLED MOISTURE NEAR THIS WEAKENING BOUNDARY WILL RESULT IN
INCREASINGLY HUMID CONDITIONS LATER TONIGHT INTO TUESDAY. FAIRLY
EXTENSIVE AREA OF MVFR/IFR CIGS ACROSS IA AND WI CURRENTLY...AND
MODEL GUIDANCE DEPICTS A GRADUAL DETERIORATION OF CIG/VIS CONDITIONS
INTO MVFR ACROSS NORTHERN IL AND NORTHWEST IN TERMINALS OVERNIGHT.
AM A LITTLE RELUCTANT TO FORECAST CONDITIONS TOO LOW AT THIS POINT
WITH RAIN HAVING BEEN MORE SPOTTY THAN MANY MODEL FORECASTS
INDICATED...THOUGH DEVELOPMENT OF MVFR CIG/VIS CONDITIONS DOES
SEEM REASONABLE GIVEN PERSISTENT ALBEIT LIGHT WEST-SOUTHWEST FLOW
IN LOW LEVELS AND AFOREMENTIONED MOISTURE POOLING/HUMID BOUNDARY
LAYER AND SCATTERING OF HIGHER CLOUD LAYERS OVERNIGHT IN WAKE OF
AFOREMENTIONED DISTURBANCE. WITH FRONT BECOMING LESS DISCERNIBLE
WITH TIME...AND LITTLE DYNAMIC PUSH FOR CLEARING...IT MAY TAKE
SEVERAL HOURS TUESDAY MORNING FOR IMPROVEMENT BACK TO VFR.
WINDS HAVE BACKED SLIGHTLY TO SOUTH-SOUTHEAST LATE THIS
AFTERNOON/EARLY EVENING...THOUGH THEY SHOULD EVENTUALLY SETTLE
BACK TO MORE OF A SOUTH-SOUTHWEST DIRECTION OVERNIGHT AND TUESDAY
AHEAD OF STALLING FRONTAL BOUNDARY. SPEEDS EXPECTED TO BE
GENERALLY 10 KT OR LESS TONIGHT...AROUND 10 KT WITH PERHAPS A FEW
GUSTS NEAR 15 KT BY TUESDAY AFTERNOON.
NEXT UPPER DISTURBANCE OF SUBSTANCE APPROACHES THE AREA TUESDAY
NIGHT...WHICH LOOKS TO GRADUALLY INCREASE POTENTIAL FOR SHRA/TSRA
BEYOND 00Z WED.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN SHRA TRENDS THIS EVENING.
* MEDIUM CONFIDENCE IN MVFR CIG/VIS CONDITIONS DEVELOPING LATER
THIS EVENING/OVERNIGHT AND LINGERING INTO TUESDAY MORNING.
* LOW CONFIDENCE IN CIG HEIGHT TRENDS TUESDAY...ESPECIALLY
MORNING.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...CHANCE TSRA MAINLY MORNING. OTHERWISE VFR.
THURSDAY THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY SOUTH OF
CHICAGO THURSDAY NIGHT.
RATZER
&&
.MARINE...
240 PM...A BROAD WEAK TROUGH EXTENDING ACROSS THE PLAINS FROM A
SLIGHTLY STRONGER LOW OVER ONTARIO WILL SLOWLY MOVE EAST ACROSS
THE WESTERN LAKES WEDNESDAY...WITH THE LOW OVER ONTARIO SLOWLY
MOVING EAST THROUGH MID WEEK. AHEAD OF THIS TROUGH...SOUTHERLY
WINDS HAVE INCREASED TO 10-20 KT AND FORECAST SOUNDINGS SUGGEST
THE POTENTIAL FOR SOME WINDS INTO THE 15-25 KT RANGE THIS EVENING
BEFORE SLOWLY DIMINISHING OVERNIGHT. ONCE THE TROUGH/COLD FRONT
MOVES ACROSS THE LAKE MIDDAY WEDNESDAY...WINDS WILL SHIFT
NORTHERLY WITH A PERIOD OF 10-20 KTS POSSIBLE BUT APPEARS THAT
WOULD BE SHORT LIVED AS HIGH PRESSURE SPREADS ACROSS THE LAKES
REGION WEDNESDAY NIGHT INTO THURSDAY. THE LOW OVER ONTARIO FINALLY
SHIFTS EAST INTO QUEBEC ON FRIDAY...WITH A WEAK COLD FRONT MOVING
ACROSS THE WESTERN LAKES FRIDAY NIGHT SHIFTING WINDS BACK
NORTHERLY INTO SATURDAY WITH ANOTHER HIGH MOVING ACROSS THE LAKES
SATURDAY NIGHT INTO SUNDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
920 AM CDT Sun Aug 4 2013
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
ISSUED AT 912 AM CDT SUN AUG 4 2013
A weak upper level ridge of high pressure remains situated across
the western high plains and the south plains of west Texas. A
strong +110kt upper level jet is streaming southeast out of the
western Great Lakes Region into the upper Ohio River Valley. Near
the surface, a large area of high pressure is drifting slowly east
across the upper midwest. Ample low level moisture remains across
central and southwest Kansas with surface dewpoints mainly in the
mid to upper 60s(F).
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 321 AM CDT SUN AUG 4 2013
Precipitation chances will remain high through the early morning
hours in most areas across southwest Kansas, and at least moderate
into the late morning and afternoon. The latest NAM model forecast
fields indicate segments of a disjointed 400 mb level PV anomaly
still rotating eastward along the upper ridge apex, which will
likely continue to set off heavy rain showers through the day.
We`ve increased shower chances to near 50 percent into the early
afternoon. The severe threat has been negligible and that trend is
continued to be expected. The shower and thunderstorms will remain
very efficient heavy rain producers in this tropical deep moist
convective environment.
The latest Nam maximum temperature forecast is far more reasonable
as well with the highs this afternoon; a range of around 80 degrees
near Hays to near 90 degrees near the Oklahoma panhandle. although
the atmosphere should be weakly conditionally unstable again tonight
the lack of forcing mechanisms and latest model precipitation field
support a generally low probability of significant convection.
.LONG TERM...(Monday through Saturday)
ISSUED AT 321 AM CDT SUN AUG 4 2013
Upper level ridge axis will weaken early next week as a upper level
disturbance moves out of the south central Canada and starts to
cross the northern plains. the GFS and ECMWF both were in decent
agreement with this upper level system crossing the plains Tuesday
night and Wednesday and as it does a cold front will move south
across Kansas. Moisture convergence along this front along with
improving upper level dynamics ahead of the 500mb trough/right
entrance region of a 250mb jet supports the improving chances for
convection Tuesday night into early Wednesday. This boundary is
forecast to moving into Oklahoma on Thursday as an ridge of high
pressure at the surface builds into the central plains. Given the
warm air advection and isentropic lift north of this front on
Thursday will favor the latest CRExtendFcst_Init with chance/slight
chance for precipitation. As the ridge of high pressure late builds
into Kansas late week the chances may decrease, however given some
uncertainty on the location of where the front will be late week
along with any moisture upslope flow north of this front am
reluctant to remove all mention of precipitation just yet.
As for temperatures next week...the warming trend Monday and Tuesday
still looks on track given the 850mb temperature trend. Behind the
cold front highs only in the 80s still appears reasonable.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 613 AM CDT SUN AUG 4 2013
VFR conditions will develop as showers and thunderstorms taper
off from west to east. Bufr soundings and HRRR both suggest low
level status will be possible with these thunderstorms and given
the 10z surface observations will keep these cigs in the ifr
category as these showers and thunderstorms pass. Given the latest
radar trend it appears precipitation will continue in/near the Hays
area until around 15z so will also keep status present until then.
further southwest VFR conditions were already observed at Dodge
and Garden City. The prevailing wind direction outside the early
morning thunderstorms will be southeast at 10 to 15kts.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 67 100 69 / 70 20 20 20
GCK 86 67 100 69 / 40 20 20 20
EHA 91 67 100 70 / 40 20 20 20
LBL 94 70 102 70 / 40 20 20 20
HYS 83 68 93 69 / 60 20 30 30
P28 89 70 99 73 / 90 20 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJOHNSON
SHORT TERM...RUSSELL
LONG TERM...BURGERT
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
615 AM CDT Sun Aug 4 2013
...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 321 AM CDT SUN AUG 4 2013
Very heavy rain producing thunderstorms were anchored along a 300k
level isentropic lift zone from near Scott City to near Pratt. The
heaviest rainfall fell along a narrow zone over central and eastern
Hodgeman county where dual pol radar estimates of as much as 5
inches fell. As of 2 am, the convection has become not as tied to
that narrow corridor and more scattered in nature. The mesoanalysis
indicated precipitable water across the area had increase to above
the 99th percentile at 2 inches at Dodge City.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 321 AM CDT SUN AUG 4 2013
Precipitation chances will remain high through the early morning
hours in most areas across southwest Kansas, and at least moderate
into the late morning and afternoon. The latest NAM model forecast
fields indicate segments of a disjointed 400 mb level PV anomaly
still rotating eastward along the upper ridge apex, which will
likely continue to set off heavy rain showers through the day.
We`ve increased shower chances to near 50 percent into the early
afternoon. The severe threat has been negligible and that trend is
continued to be expected. The shower and thunderstorms will remain
very efficient heavy rain producers in this tropical deep moist
convective environment.
The latest Nam maximum temperature forecast is far more reasonable
as well with the highs this afternoon; a range of around 80 degrees
near Hays to near 90 degrees near the Oklahoma panhandle. although
the atmosphere should be weakly conditionally unstable again tonight
the lack of forcing mechanisms and latest model precipitation field
support a generally low probability of significant convection.
.LONG TERM...(Monday through Saturday)
ISSUED AT 321 AM CDT SUN AUG 4 2013
Upper level ridge axis will weaken early next week as a upper level
disturbance moves out of the south central Canada and starts to
cross the northern plains. the GFS and ECMWF both were in decent
agreement with this upper level system crossing the plains Tuesday
night and Wednesday and as it does a cold front will move south
across Kansas. Moisture convergence along this front along with
improving upper level dynamics ahead of the 500mb trough/right
entrance region of a 250mb jet supports the improving chances for
convection Tuesday night into early Wednesday. This boundary is
forecast to moving into Oklahoma on Thursday as an ridge of high
pressure at the surface builds into the central plains. Given the
warm air advection and isentropic lift north of this front on
Thursday will favor the latest CRExtendFcst_Init with chance/slight
chance for precipitation. As the ridge of high pressure late builds
into Kansas late week the chances may decrease, however given some
uncertainty on the location of where the front will be late week
along with any moisture upslope flow north of this front am
reluctant to remove all mention of precipitation just yet.
As for temperatures next week...the warming trend Monday and Tuesday
still looks on track given the 850mb temperature trend. Behind the
cold front highs only in the 80s still appears reasonable.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 613 AM CDT SUN AUG 4 2013
VFR conditions will develop as showers and thunderstorms taper
off from west to east. Bufr soundings and HRRR both suggest low
level status will be possible with these thunderstorms and given
the 10z surface observations will keep these cigs in the ifr
category as these showers and thunderstorms pass. Given the latest
radar trend it appears precipitation will continue in/near the Hays
area until around 15z so will also keep status present until then.
further southwest VFR conditions were already observed at Dodge
and Garden City. The prevailing wind direction outside the early
morning thunderstorms will be southeast at 10 to 15kts.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 68 100 69 / 80 20 20 20
GCK 86 68 100 69 / 90 20 20 20
EHA 91 68 100 70 / 40 20 20 20
LBL 94 71 101 70 / 40 20 20 20
HYS 83 70 93 69 / 90 20 30 30
P28 89 71 99 73 / 80 20 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RUSSELL
SHORT TERM...RUSSELL
LONG TERM...BURGERT
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1026 PM EDT MON AUG 5 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC STATES MOVES OFF THE COAST
TONIGHT AND TUESDAY. A WARM FRONT WILL LIFT BACK NORTH INTO THE
REGION LATE TONIGHT THROUGH TUESDAY. A MOIST AIR MASS WILL PREVAIL
THE REST OF THE WEEK...RESULTING IN DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TUESDAY/...
THE LATEST WATER VAPOR IMAGERY ALONG WITH 00Z UPPER AIR
OBSERVATIONS INDICATE NW MID/UPPER FLOW FROM THE UPPER MIDWEST
THROUGH THE MID ATLANTIC BETWEEN TWO PRIMARY TROUGHS OVER CENTRAL
AND ATLANTIC CANADA...AND AN UPPER RIDGE CENTERED OVER TX. WV
IMAGERY INDICATES A SHORTWAVE TROUGH DIVING ESE ACROSS THE LOWER
GREAT LAKES. WAA RETURNS AHEAD OF THIS FEATURE LATE TONIGHT ALONG
WITH ISENTROPIC LIFT AROUND THE 305-310K RANGE. IN EFFECT...THE
80H WARM FRONT WILL PASS THROUGH THE AREA TUESDAY MORNING. THIS
WILL BEGIN OVER THE MOUNTAINS OF SOUTHWEST VIRGINIA AND DEVELOP TO
THE E AND NE. THE LAST FEW RUNS OF THE RUC ALONG WITH SUPPORT FROM
THE 18Z NAM/GFS INDICATE RATHER STRONG LIFT OVER THE NW QUADRANT
OF THE CWA LATE TONIGHT INTO EARLY TUESDAY MORNING (08-12Z). GIVEN
THIS...POPS WERE RAISED TO LIKELY FOR THE NW CORNER OF THE AREA
DURING THIS TIMEFRAME. OTHERWISE...POPS REMAIN AS IS FOR REST OF
THE AREA.
LOW TEMPERATURES WILL RANGE FROM THE LOWER 60S ON THE LOWER EASTERN
SHORE TO THE MID AND UPR 60S ELSEWHERE.
ON TUESDAY...FOLLOWED CLOSE TO NAM FORECAST. BOTH THE NAM AND MOS
GUIDE HAVE THE HIGHEST POPS OVER THE FAR NORTH PART OF OUR AREA
(DORCHESTER COUNTY MD AND PART OF THE NORTHERN NECK). HAVE LIKELY
POPS IN THIS AREA THROUGH EARLY TUESDAY AFTN. A CHANCE FOR SHOWERS
AND THUNDERSTORMS WILL EXTEND ACROSS THE CWA TUESDAY AFTN WITH
LOWEST POPS (20 PERCENT) JUST ALONG THE ALBEMARLE SOUND. KEPT
THUNDERSTORM MENTION TO SLIGHT CHANCE UNTIL 18Z TUESDAY.
TEMPERATURES WILL BE HELD DOWN SOME BY CLOUD COVER AND PCPN WITH
READINGS AROUND 80 IN THE NORTH TO THE MID 80S NEAR THE VA/NC
BORDER.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
CONTINUED WITH THE CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH MOST
OF THE SHORT TERM PERIOD. MOST POPS ARE IN THE 30 TO 40 PERCENT
RANGE. DEEPEST MOISTURE APPEARS TO BE OVER THE NORTHWEST HALF OF THE
AREA. SOME LOCALLY HEAVY RAINFALL IS POSSIBLE...MAINLY WEST OF I95
AND ACROSS THE NORTHERN COUNTIES...BUT DO NOT SEE A NEED TO
HIGHLIGHT IN THE HWO AT THIS POINT.
HIGHEST CHANCES APPEAR TO BE WEDNESDAY NIGHT WHEN MOST MODELS
INDICATE A SHORT WAVE MOVING THROUGH. WITH THIS BEING IN THE FIFTH
PERIOD...HIGHEST CHANCES ARE ACROSS OUR NORTHERN AREAS...SIMILAR TO
TUESDAY MORNING. WAS NOT CONFIDENT ENOUGH WITH THE TIMING TO GO
LIKELY AT THIS POINT. HIGH TEMPERATURES WEDNESDAY ARE FORECAST TO BE
IN THE LOW TO MID 80S WEDNESDAY AND MID 80S TO NEAR 90 ON THURSDAY.
LOWS SHOULD RANGE FROM 65 TO 70.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MEDIUM RANGE MODELS CONTINUE TO HANDLE THE OVERALL UPPER PATTERN
WELL. STRONG UPPER LEVEL CLOSED LOW WILL BEGIN TO EJECT EWD FRI AS A
SPEED MAX ROUNDS THE BASE OF THE LOW...AMPLIFYING A MID LEVEL TROUGH
OVER THE NE STATES. THE EJECTING LOW WILL PUSH A SFC LOW THRU SE
CANADA WITH AN ATTENDANT COLD FRONT STRETCHING SWWD INTO THE OH
VALLEY. MEANWHILE...MID LEVEL HIGH PRESSURE WILL LOCATE JUST OFF THE
SOUTHEAST COAST FRI WITH RIDGING OVER THE WRN ATLANTIC. THE RESULT
WILL BE INCREASING SW FLOW OVER THE LOCAL AREA. PRECIP WATER VALUES
PROGGED TO INCREASE AOA 2 INCHES FRI AFTERNOON WITH STRONG H85
MOISTURE TRANSPORT. SHORTWAVE ENERGY EMBEDDED IN THE WSW FLOW ALOFT
WILL PROVIDE SUBTLE FORCING FOR ASCENT FRI AFTERNOON. LEE SIDE
TROUGH AND THE APPROACHING COLD FRONT...AS WELL AS LOCAL CONVERGENCE
BOUNDARIES...WILL COMBINE WITH MID LEVEL FORCING AND ABUNDANT
MOISTURE FOR SCATTERED SHOWERS AND THUNDERSTORMS FRI AFTERNOON. THE
BEST COVERAGE WILL BE OVER THE PIEDMONT...CLOSEST TO THE FRONT AND
BEST MOISTURE. HIGH PRESSURE AND LESS MOISTURE ALONG THE COAST WILL
LIMIT PRECIP CHANCES ACROSS THE SE. AS THE UPPER LEVEL FORCING WANES
FRI NIGHT IN ADVANCE OF THE FRONT...EXPECT PRECIP CHANCES TO
DIMINISH LATE FRI NIGHT/EARLY SAT MORNING. THE FRONT WILL SAG SWD
THROUGH THE LOCAL AREA SAT. ADDITIONAL SHORTWAVE ENERGY AS WELL AS
RRQ OF 70 KT UPPER LEVEL JET WILL PROVIDE BETTER FORCING FOR ASCENT
SAT ALONG THE COLD FRONT...RESULTING IN BETTER COVERAGE (ALBEIT
CHANCE) OF SHOWERS AND THUNDERSTORMS OVER THE LOCAL AREA. REGARDLESS
OF ABUNDANT MOISTURE (+1 TO +2 STD DEV PRECIP WATER) AND LIMITED
FORCING FOR ASCENT...THE BEST DYNAMICS WILL REMAIN WELL NORTH OF THE
LOCAL AREA. THIS WILL LIKELY LIMIT THE COVERAGE OF
SHOWERS/THUNDERSTORMS...BUT LOCALLY HEAVY RAINFALL WILL STILL BE
POSSIBLE DUE TO THE VERY MOIST AIRMASS. FLOW PARALLEL TO THE FRONT
AND HIGH PRESSURE ALONG THE SE COAST WILL RESULT IN THE FRONT
SLOWING AS IT REACHES THE COAST. WILL HOLD ONTO SLIGHT CHANCE-CHANCE
POPS ACROSS THE SE SUN TO ACCOUNT FOR THE SLOWING FRONT. HIGH
PRESSURE WILL THEN BUILD IN BEHIND THE DEPARTING COLD FRONT.
HOWEVER...COLDEST AIR EXPECTED TO REMAIN NORTH OF THE LOCAL AREA.
MAIN CHANGES POST FRONTAL WILL BE DRIER AIR AND NLY WINDS.
TEMPS DURING THE EXTENDED WILL REMAIN AROUND SEASONABLE NORMS
(MID/UPPER 80S) UNDER PARTLY CLOUDY TO MOSTLY CLOUDY SKIES. MILD
OVERNIGHT TEMPS WITH LOWS GENERALLY IN THE UPPER 60S/LOW 70S. HUMID
FRI-SAT BEFORE DRYING OUT POST FRONTAL SAT NIGHT-MON.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL PREVAIL THIS EVENING ALTHOUGH INCREASING
MOISTURE FROM AN APPROACHING WARM FRONT WILL BRING BKN/OVC
CONDITIONS TO MOST OF THE AREA BETWEEN 06-12Z. FAIRLY DRY LOW
LEVELS SHOULD TEND TO KEEP CIGS ABOVE 3 K FT EVEN THOUGH -RA WAS
ADDED TO TAFS AT KRIC/KPHF/KSBY PRIOR TO 12Z (CHANCE FOR ANY TSTMS
IS TOO LOW TO INCLUDE IN TAFS). WINDS SHIFT FROM SE TO S/SW TUE
AFTN WITH THE POTENTIAL FOR AT LEAST SCATTERED SHRA OR TSRA BUT
GIVEN UNCERTAINTY WENT WITH "VCSH" IN TAFS FOR NOW.
OTHERWISE...SOMEWHAT WARMER AND MORE HUMID AIRMASS WILL PREVAIL
WED-FRI WITH SHOWERS AND TSTMS POSSIBLE MAINLY IN THE AFTN/EVENING
HRS. COLD FRONT SLOWLY PUSHES THROUGH ON SAT...BRINGING WITH IT
CONTINUED CHANCES FOR SHRA/TSRA.
&&
.MARINE...
LIGHT N-NE WINDS AOB 10 KT OVER THE WATERS TODAY AS HIGH PRESSURE
ORIENTS ALONG THE MID ATLANTIC COAST. HIGH PRESSURE WILL CONTINUE
TO SLIDE OFFSHORE TONIGHT AS WINDS TURN TO THE S-SE. A WARM FRONT
WILL LIFT THROUGH THE MID ATLANTIC REGION LATE TUE-WED. WINDS WILL
INCREASE BEHIND THE FRONT AS THE GRADIENT TIGHTENS BTWN HIGH
PRESSURE OFFSHORE AND LOW PRESSURE OVER THE GREAT LAKES
REGION...BUT ARE EXPECTED TO REMAIN BELOW SCA SPEEDS. SOME SLY
CHANNELING MAY LEAD TO ENHANCED WINDS OVER THE MIDDLE BAY TUES
NIGHT-WED. GRADIENT WILL REMAIN THROUGH THURS WITH SLY WINDS AOB
15 KT. S-SE WINDS OVER THE COASTAL WATERS WILL BUILD SEAS 3-5 FT
WED NIGHT-THURS OVER THE NRN COASTAL ZONES BEFORE DIMINISHING
THURS EVENING. UNSETTLED CONDITIONS WILL REMAIN OVER THE WATERS
THROUGH EARLY THIS WEEKEND AS A COLD FRONT APPROACHES FROM THE
NORTHWEST. THE FRONT IS EXPECTED TO REACH...AND STALL OVER THE
WATERS SAT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LSA
NEAR TERM...AJZ/LSA
SHORT TERM...LSA
LONG TERM...SAM
AVIATION...LKB
MARINE...SAM
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
903 AM EDT SUN AUG 4 2013
.SYNOPSIS...
AFTER A FEW MORNING SHOWERS...DRY AND COOL WEATHER CAN BE EXPECTED FOR THE
START OF THE NEW WEEK AS HIGH PRESSURE SETTLES OVER THE UPPER OHIO VALLEY
REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
DENSE FOG ADZY HAS BEEN ALLOWED TO EXPIRE AS SCHEDULED. PREV
DISCUSSION FOLLOWS...
7AM UPDATE. ADDED DENSE FOG TO WESTMORELAND FAYETTE GARRETT TUCKER
AND PRESTON COUNTIES. ADDED DENSE FOG ADVISORY TILL 9AM FOR THESE COUNTIES.
PREVIOUS DISCUSSION...
NR DAWN UPDATE WAS ISSUED TO ADJUST FOR HOURLY TRENDS OF
TEMP AND PCPN PROBABILITY.
FEW SHOWERS THAT HAVE FORMED N OF I 80 ALNG A SFC TROF/WEAK
SECONDARY FRONT HAVE SAGGED SWD THIS MRNG TWD THE METRO AREA.
SLGT TO CHC POPS WERE THUS MAINTAINED PAST DAWN IN ACCORDANCE
WITH LATEST RUC GUIDCANCE AND RADAR TRENDS.
OTHERWISE...SFC HIGH PRES UNDR NW FLOW ALOFT WL SETTLE OVR THE
GREAT LAKES AND UPR OH REGIONS TDA. CONVECTIVE THRESHOLDS ARE
EXPECTED TO BE EXCEEDED BY LATE MRNG...HENCE STRATOCU/CU DVLPMNT
SHOULD BE SUFFICIENTLY EXTENSIVE FOR AT LEAST A BROKEN CLOUD DECK.
THE PROGGED MIXING LAYER APPEARS SUFFICIENTLY SHALLOW TO PRECLUDE
SHOWER DVLPMNT THIS AFTN...SO A DRY FORECAST WL BE INITIALLY
RETAINED. DUE TO THE EXPANSE IN CLOUD COVER...TEMPS ARE FORECAST
ABOUT 10 DEGREES BELOW SEASONAL AVERAGES.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
SHRTWV IN THE NW FLOW THAT IS NAM AND GFS PROJECTED ACRS THE
GREAT LAKES LTR ON MONDAY...WL REINITIATE WARM ADVCTN WITH THE
ADVN TWD THE UPR OH VALLEY. A SLIGHT...LATE DAY SHWR CHC WAS
INCLUDED FOR ZONES FM PIT SWD...WHERE SOME WEAK ELEVATED
CONVECTION MAY DVLP TO THE N OF THE SLOWLY RTNG SFC BNDRY.
RAIN CHCS THEREAFTER WL GRADUALLY INCRS THROUGH THE SHORT TERM PD
AS WARM FRONT SURGES NWD UNDR A SERIES OF CROSSING DISTURBANCES.
THE WARM ADVCTN REGIME WL QUICKLY MODERATE SHORT TERM TEMPS CLOSE
TO THE SEASONAL AVERAGES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS AND ECMWF RMN IN GENL AGRMNT IN DVLPG A DEEP UPR LOW OVR
MANITOBA BY MIDWEEK...THEN PR0JECTING IT TWD/ACRS JAMES BAY BY THE
WEEKEND. EWD PROGRESS OF THE LOW WL SEND A CDFNT ACRS THE AREA...HENCE
THE POP INCRS FOR THU...ALTHOUGH A DEEP MSTR SURGE IS NOT ANTICIPATED
GIVEN THE ENTRENCHMENT OF A BROAD RIDGE OVR THE GULF COAST STATES.
POST FRONTAL TEMPS WERE FORECAST CONSERVATIVELY...JUST A FEW
DEGREES UNDR THE AVERAGES FOR NXT WEEKEND.
&&
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
IFR FOG IN THE SOUTH TO BEGIN THE FORECAST. ELSEWHERE GENERAL VFR
WITH MID-DECK AND AN ISO NON-RESTRICTIVE SHOWER.
VFR FORECAST FOR ALL PORTS SHORTLY AFTER DAWN WITH BKN-OVC CU
EXPECTED THROUGH THE REST OF THE DAY.
OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... NO WIDESPREAD IFR
WEATHER IS PREDICTED. PATTERN BECOMES UNSETTLED BY TUESDAY
NIGHT...WITH A CHANCE OF SHOWERS/THUNDERSTORMS TUESDAY NIGHT
THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
UPDATE...KRAMAR
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
708 AM EDT SUN AUG 4 2013
.SYNOPSIS...
AFTER A FEW MORNING SHOWERS...DRY AND COOL WEATHER CAN BE EXPECTED FOR THE
START OF THE NEW WEEK AS HIGH PRESSURE SETTLES OVER THE UPPER OHIO VALLEY
REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
7AM UPDATE. ADDED DENSE FOG TO WESTMORELAND FAYETTE GARRETT TUCKER
AND PRESTON COUNTIES. ADDED DENSE FOG ADVISORY TILL 9AM FOR THESE COUNTIES.
PREVIOUS DISCUSSION...
NR DAWN UPDATE WAS ISSUED TO ADJUST FOR HOURLY TRENDS OF
TEMP AND PCPN PROBABILITY.
FEW SHOWERS THAT HAVE FORMED N OF I 80 ALNG A SFC TROF/WEAK
SECONDARY FRONT HAVE SAGGED SWD THIS MRNG TWD THE METRO AREA.
SLGT TO CHC POPS WERE THUS MAINTAINED PAST DAWN IN ACCORDANCE
WITH LATEST RUC GUIDCANCE AND RADAR TRENDS.
OTHERWISE...SFC HIGH PRES UNDR NW FLOW ALOFT WL SETTLE OVR THE
GREAT LAKES AND UPR OH REGIONS TDA. CONVECTIVE THRESHOLDS ARE
EXPECTED TO BE EXCEEDED BY LATE MRNG...HENCE STRATOCU/CU DVLPMNT
SHOULD BE SUFFICIENTLY EXTENSIVE FOR AT LEAST A BROKEN CLOUD DECK.
THE PROGGED MIXING LAYER APPEARS SUFFICIENTLY SHALLOW TO PRECLUDE
SHOWER DVLPMNT THIS AFTN...SO A DRY FORECAST WL BE INITIALLY
RETAINED. DUE TO THE EXPANSE IN CLOUD COVER...TEMPS ARE FORECAST
ABOUT 10 DEGREES BELOW SEASONAL AVERAGES.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
SHRTWV IN THE NW FLOW THAT IS NAM AND GFS PROJECTED ACRS THE
GREAT LAKES LTR ON MONDAY...WL REINITIATE WARM ADVCTN WITH THE
ADVN TWD THE UPR OH VALLEY. A SLIGHT...LATE DAY SHWR CHC WAS
INCLUDED FOR ZONES FM PIT SWD...WHERE SOME WEAK ELEVATED
CONVECTION MAY DVLP TO THE N OF THE SLOWLY RTNG SFC BNDRY.
RAIN CHCS THEREAFTER WL GRADUALLY INCRS THROUGH THE SHORT TERM PD
AS WARM FRONT SURGES NWD UNDR A SERIES OF CROSSING DISTURBANCES.
THE WARM ADVCTN REGIME WL QUICKLY MODERATE SHORT TERM TEMPS CLOSE
TO THE SEASONAL AVERAGES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS AND ECMWF RMN IN GENL AGRMNT IN DVLPG A DEEP UPR LOW OVR
MANITOBA BY MIDWEEK...THEN PR0JECTING IT TWD/ACRS JAMES BAY BY THE
WEEKEND. EWD PROGRESS OF THE LOW WL SEND A CDFNT ACRS THE AREA...HENCE
THE POP INCRS FOR THU...ALTHOUGH A DEEP MSTR SURGE IS NOT ANTICIPATED
GIVEN THE ENTRENCHMENT OF A BROAD RIDGE OVR THE GULF COAST STATES.
POST FRONTAL TEMPS WERE FORECAST CONSERVATIVELY...JUST A FEW
DEGREES UNDR THE AVERAGES FOR NXT WEEKEND.
&&
.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
IFR FOG IN THE SOUTH TO BEGIN THE FORECAST. ELSEWHERE GENERAL VFR
WITH MID-DECK AND AN ISO NON-RESTRICTIVE SHOWER.
VFR FORECAST FOR ALL PORTS SHORTLY AFTER DAWN WITH BKN-OVC CU
EXPECTED THROUGH THE REST OF THE DAY.
OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... NO WIDESPREAD IFR
WEATHER IS PREDICTED. PATTERN BECOMES UNSETTLED BY TUESDAY
NIGHT...WITH A CHANCE OF SHOWERS/THUNDERSTORMS TUESDAY NIGHT
THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR MDZ001.
OH...NONE.
PA...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR PAZ073>076.
WV...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
657 AM EDT SUN AUG 4 2013
.SYNOPSIS...
AFTER A FEW MORNING SHOWERS...DRY AND COOL WEATHER CAN BE EXPECTED FOR THE
START OF THE NEW WEEK AS HIGH PRESSURE SETTLES OVER THE UPPER OHIO VALLEY
REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
7AM UPDATE. ADDED DENSE FOG TO WESTMORELAND FAYETTE GARRETT TUCKER
AND PRESTON COUNTIES.
PREVIOUS DISCUSSION...
NR DAWN UPDATE WAS ISSUED TO ADJUST FOR HOURLY TRENDS OF
TEMP AND PCPN PROBABILITY.
FEW SHOWERS THAT HAVE FORMED N OF I 80 ALNG A SFC TROF/WEAK
SECONDARY FRONT HAVE SAGGED SWD THIS MRNG TWD THE METRO AREA.
SLGT TO CHC POPS WERE THUS MAINTAINED PAST DAWN IN ACCORDANCE
WITH LATEST RUC GUIDCANCE AND RADAR TRENDS.
OTHERWISE...SFC HIGH PRES UNDR NW FLOW ALOFT WL SETTLE OVR THE
GREAT LAKES AND UPR OH REGIONS TDA. CONVECTIVE THRESHOLDS ARE
EXPECTED TO BE EXCEEDED BY LATE MRNG...HENCE STRATOCU/CU DVLPMNT
SHOULD BE SUFFICIENTLY EXTENSIVE FOR AT LEAST A BROKEN CLOUD DECK.
THE PROGGED MIXING LAYER APPEARS SUFFICIENTLY SHALLOW TO PRECLUDE
SHOWER DVLPMNT THIS AFTN...SO A DRY FORECAST WL BE INITIALLY
RETAINED. DUE TO THE EXPANSE IN CLOUD COVER...TEMPS ARE FORECAST
ABOUT 10 DEGREES BELOW SEASONAL AVERAGES.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
SHRTWV IN THE NW FLOW THAT IS NAM AND GFS PROJECTED ACRS THE
GREAT LAKES LTR ON MONDAY...WL REINITIATE WARM ADVCTN WITH THE
ADVN TWD THE UPR OH VALLEY. A SLIGHT...LATE DAY SHWR CHC WAS
INCLUDED FOR ZONES FM PIT SWD...WHERE SOME WEAK ELEVATED
CONVECTION MAY DVLP TO THE N OF THE SLOWLY RTNG SFC BNDRY.
RAIN CHCS THEREAFTER WL GRADUALLY INCRS THROUGH THE SHORT TERM PD
AS WARM FRONT SURGES NWD UNDR A SERIES OF CROSSING DISTURBANCES.
THE WARM ADVCTN REGIME WL QUICKLY MODERATE SHORT TERM TEMPS CLOSE
TO THE SEASONAL AVERAGES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS AND ECMWF RMN IN GENL AGRMNT IN DVLPG A DEEP UPR LOW OVR
MANITOBA BY MIDWEEK...THEN PR0JECTING IT TWD/ACRS JAMES BAY BY THE
WEEKEND. EWD PROGRESS OF THE LOW WL SEND A CDFNT ACRS THE AREA...HENCE
THE POP INCRS FOR THU...ALTHOUGH A DEEP MSTR SURGE IS NOT ANTICIPATED
GIVEN THE ENTRENCHMENT OF A BROAD RIDGE OVR THE GULF COAST STATES.
POST FRONTAL TEMPS WERE FORECAST CONSERVATIVELY...JUST A FEW
DEGREES UNDR THE AVERAGES FOR NXT WEEKEND.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
IFR FOG IN THE SOUTH TO BEGIN THE FORECAST. ELSEWHERE GENERAL VFR
WITH MID-DECK AND AN ISO NON-RESTRICTIVE SHOWER.
VFR FORECAST FOR ALL PORTS SHORTLY AFTER DAWN WITH BKN-OVC CU
EXPECTED THROUGH THE REST OF THE DAY.
OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... NO WIDESPREAD IFR
WEATHER IS PREDICTED. PATTERN BECOMES UNSETTLED BY TUESDAY
NIGHT...WITH A CHANCE OF SHOWERS/THUNDERSTORMS TUESDAY NIGHT
THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
520 AM EDT SUN AUG 4 2013
.SYNOPSIS...
AFTER A FEW MORNING SHOWERS...DRY AND COOL WEATHER CAN BE EXPECTED FOR THE
START OF THE NEW WEEK AS HIGH PRESSURE SETTLES OVER THE UPPER OHIO VALLEY
REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
NR DAWN UPDATE WAS ISSUED TO ADJUST FOR HOURLY TRENDS OF TEMP AND
PCPN PROBABILITY.
FEW SHOWERS THAT HAVE FORMED N OF I 80 ALNG A SFC TROF/WEAK
SECONDARY FRONT HAVE SAGGED SWD THIS MRNG TWD THE METRO AREA.
SLGT TO CHC POPS WERE THUS MAINTAINED PAST DAWN IN ACCORDANCE
WITH LATEST RUC GUIDCANCE AND RADAR TRENDS.
OTHERWISE...SFC HIGH PRES UNDR NW FLOW ALOFT WL SETTLE OVR THE
GREAT LAKES AND UPR OH REGIONS TDA. CONVECTIVE THRESHOLDS ARE
EXPECTED TO BE EXCEEDED BY LATE MRNG...HENCE STRATOCU/CU DVLPMNT
SHOULD BE SUFFICIENTLY EXTENSIVE FOR AT LEAST A BROKEN CLOUD DECK.
THE PROGGED MIXING LAYER APPEARS SUFFICIENTLY SHALLOW TO PRECLUDE
SHOWER DVLPMNT THIS AFTN...SO A DRY FORECAST WL BE INITIALLY
RETAINED. DUE TO THE EXPANSE IN CLOUD COVER...TEMPS ARE FORECAST
ABOUT 10 DEGREES BELOW SEASONAL AVERAGES.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
SHRTWV IN THE NW FLOW THAT IS NAM AND GFS PROJECTED ACRS THE
GREAT LAKES LTR ON MONDAY...WL REINITIATE WARM ADVCTN WITH THE
ADVN TWD THE UPR OH VALLEY. A SLIGHT...LATE DAY SHWR CHC WAS
INCLUDED FOR ZONES FM PIT SWD...WHERE SOME WEAK ELEVATED
CONVECTION MAY DVLP TO THE N OF THE SLOWLY RTNG SFC BNDRY.
RAIN CHCS THEREAFTER WL GRADUALLY INCRS THROUGH THE SHORT TERM PD
AS WARM FRONT SURGES NWD UNDR A SERIES OF CROSSING DISTURBANCES.
THE WARM ADVCTN REGIME WL QUICKLY MODERATE SHORT TERM TEMPS CLOSE
TO THE SEASONAL AVERAGES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS AND ECMWF RMN IN GENL AGRMNT IN DVLPG A DEEP UPR LOW OVR
MANITOBA BY MIDWEEK...THEN PR0JECTING IT TWD/ACRS JAMES BAY BY THE
WEEKEND. EWD PROGRESS OF THE LOW WL SEND A CDFNT ACRS THE AREA...HENCE
THE POP INCRS FOR THU...ALTHOUGH A DEEP MSTR SURGE IS NOT ANTICIPATED
GIVEN THE ENTRENCHMENT OF A BROAD RIDGE OVR THE GULF COAST STATES.
POST FRONTAL TEMPS WERE FORECAST CONSERVATIVELY...JUST A FEW
DEGREES UNDR THE AVERAGES FOR NXT WEEKEND.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
IFR FOG IN THE SOUTH TO BEGIN THE FORECAST. ELSEWHERE GENERAL VFR
WITH MID-DECK AND AN ISO NON-RESTRICTIVE SHOWER.
VFR FORECAST FOR ALL PORTS SHORTLY AFTER DAWN WITH BKN-OVC CU
EXPECTED THROUGH THE REST OF THE DAY.
OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... NO WIDESPREAD IFR
WEATHER IS PREDICTED. PATTERN BECOMES UNSETTLED BY TUESDAY
NIGHT...WITH A CHANCE OF SHOWERS/THUNDERSTORMS TUESDAY NIGHT
THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
323 AM EDT SUN AUG 4 2013
.SYNOPSIS...
DRY AND COOL WEATHER CAN BE EXPECTED FOR THE START OF THE NEW WEEK
AS HIGH PRESSURE SETTLES OVER THE UPPER OHIO VALLEY REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
FEW SHOWERS HAVE FORMED ALNG/N OF I 80 AS CROSSING SHRTWV HAS
IGNITED A SFC TROF/WEAK SECONDARY FRONT MOVG OFF LAKE ERIE.
SLGT TO CHC POPS WERE THUS INTRODUCED FOR THE MRNG OVR AREAS N OF
PIT...IN ACCORDANCE WITH LATEST RUC GUIDCANCE AND RADAR TRENDS.
OTHERWISE...SFC HIGH PRES UNDR NW FLOW ALOFT WL SETTLE OVR THE
GREAT LAKES AND UPR OH REGIONS TDA. CONVECTIVE THRESHOLDS ARE
EXPECTED TO BE EXCEEDED BY LATE MRNG...HENCE STRATOCU/CU DVLPMNT
SHOULD BE SUFFICIENTLY EXTENSIVE FOR AT LEAST A BROKEN CLOUD DECK.
THE PROGGED MIXING LAYER APPEARS SUFFICIENTLY SHALLOW TO PRECLUDE
SHOWER DVLPMNT THIS AFTN...SO A DRY FORECAST WL BE INITIALLY
RETAINED. DUE TO THE EXPANSE IN CLOUD COVER...TEMPS ARE FORECAST
ABOUT 10 DEGREES BELOW SEASONAL AVERAGES.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
SHRTWV IN THE NW FLOW THAT IS NAM AND GFS PROJECTED ACRS THE
GREAT LAKES LTR ON MONDAY...WL REINITIATE WARM ADVCTN WITH THE
ADVN TWD THE UPR OH VALLEY. A SLIGHT...LATE DAY SHWR CHC WAS
INCLUDED FOR ZONES FM PIT SWD...WHERE SOME WEAK ELEVATED
CONVECTION MAY DVLP TO THE N OF THE SLOWLY RTNG SFC BNDRY.
RAIN CHCS THEREAFTER WL GRADUALLY INCRS THROUGH THE SHORT TERM PD
AS WARM FRONT SURGES NWD UNDR A SERIES OF CROSSING DISTURBANCES.
THE WARM ADVCTN REGIME WL QUICKLY MODERATE SHORT TERM TEMPS CLOSE
TO THE SEASONAL AVERAGES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS AND ECMWF RMN IN GENL AGRMNT IN DVLPG A DEEP UPR LOW OVR
MANITOBA BY MIDWEEK...THEN PR0JECTING IT TWD/ACRS JAMES BAY BY THE
WEEKEND. EWD PROGRESS OF THE LOW WL SEND A CDFNT ACRS THE AREA...HENCE
THE POP INCRS FOR THU...ALTHOUGH A DEEP MSTR SURGE IS NOT ANTICIPATED
GIVEN THE ENTRENCHMENT OF A BROAD RIDGE OVR THE GULF COAST STATES.
POST FRONTAL TEMPS WERE FORECAST CONSERVATIVELY...JUST A FEW
DEGREES UNDR THE AVERAGES FOR NXT WEEKEND.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
QUESTION OVERNIGHT...WHERE TO PLACE RESTRICTIONS WITH FOG AND HOW
LOW TO GO WITH RESTRICTIONS. USING A COMBINATION OF CURRENT
CONDITIONS... FORECAST SOUNDINGS AND BUFKIT DATA...HAVE DECIDED TO
INCLUDE THE FOG AT ALL PORTS EXCEPT PIT...AGC AND BVI. WITH THE
EXCEPTION OF ZZV AND HLG...WILL GO WITH MVFR RESTRICTIONS
TEMPORARILY LOWERING TO IFR. AT THE PREVIOUS 2 PORTS HAVE DECIDED
ON A TEMPO GROUP OF MVFR. CURRENTLY MGW HAS GONE LIFR...WHICH
FALLS IN LINE WITH SURROUNDING PORTS IN NORTHERN WV. WILL LEAVE
THEM AT LIFR FOR THE REST OF THE NIGHT.
CONTINUING TO RELY ON THE FORECAST SOUNDINGS...ALL PORTS SHOULD SEE
BKN-OVC CU DEVELOP LATER THIS MORNING AND REMAIN THROUGH THE
FORECAST PERIOD. THE CU WILL BE IN THE VFR CAT.
HAVE LOWERED WINDS A BIT FROM PREVIOUS FORECAST...AS THE DEVELOPMENT
OF CU SHOULD PREVENT THE STRONGER WINDS ALOFT FROM MIXING DOWN.
OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
NO WIDESPREAD IFR WEATHER IS PREDICTED. PATTERN BECOMES UNSETTLED
BY TUESDAY NIGHT...WITH A CHANCE OF SHOWERS/THUNDERSTORMS TUESDAY
NIGHT THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
15/22
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
126 AM EDT SUN AUG 4 2013
.SYNOPSIS...
DRY AND COOL WEATHER CAN BE EXPECTED FOR THE START OF THE NEW WEEK
AS HIGH PRESSURE SETTLES OVER THE UPPER OHIO VALLEY REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
FEW SHOWERS HAVE FORMED TO THE N OF I 80 AS CROSSING SHRTWV HAS
IGNITED A SFC TROF/WEAK SECONDARY FRONT MOVG OFF LAKE ERIE.
SLGT/ISOLD POPS HAVE THUS BEEN INTRODUCED FOR THE MRNG OVR AREAS N
OF PIT...IN ACCORDANCE WITH LATEST RUC GUIDCANCE AND RADAR TRENDS.
OTHERWISE...SFC HIGH PRES UNDR NW FLOW ALOFT WL SETTLE OVR THE
GREAT LAKES AND UPR OH REGIONS TDA. CONVECTIVE THRESHOLDS ARE
EXPECTED TO BE EXCEEDED BY LATE MRNG...HENCE STRATOCU/CU DVLPMNT
SHOULD BE SUFFICIENTLY EXTENSIVE FOR AT LEAST A BROKEN CLOUD DECK.
THE PROGGED MIXING LAYER APPEARS SUFFICIENTLY SHALLOW TO PRECLUDE
SHOWER DVLPMNT THIS AFTN...SO A DRY FORECAST WL BE INITIALLY
RETAINED. DUE TO THE EXPANSE IN CLOUD COVER...TEMPS ARE FORECAST
ABOUT 10 DEGREES BELOW SEASONAL AVERAGES.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
SHRTWV IN THE NW FLOW THAT IS NAM AND GFS PROJECTED ACRS THE
GREAT LAKES LTR ON MONDAY...WL REINITIATE WARM ADVCTN WITH THE
ADVN TWD THE UPR OH VALLEY. A SLIGHT...LATE DAY SHWR CHC WAS
INCLUDED FOR ZONES FM PIT SWD...WHERE SOME WEAK ELEVATED
CONVECTION MAY DVLP TO THE N OF THE SLOWLY RTNG SFC BNDRY.
RAIN CHCS THEREAFTER WL GRADUALLY INCRS THROUGH THE SHORT TERM PD
AS WARM FRONT SURGES NWD UNDR A SERIES OF CROSSING DISTURBANCES.
THE WARM ADVCTN REGIME WL QUICKLY MODERATE SHORT TERM TEMPS CLOSE
TO THE SEASONAL AVERAGES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS AND ECMWF RMN IN GENL AGRMNT IN DVLPG A DEEP UPR LOW OVR
MANITOBA BY MIDWEEK...THEN PR0JECTING IT TWD/ACRS JAMES BAY BY THE
WEEKEND. EWD PROGRESS OF THE LOW WL SEND A CDFNT ACRS THE AREA...HENCE
THE POP INCRS FOR THU...ALTHOUGH A DEEP MSTR SURGE IS NOT ANTICIPATED
GIVEN THE ENTRENCHMENT OF A BROAD RIDGE OVR THE GULF COAST STATES.
POST FRONTAL TEMPS WERE FORECAST CONSERVATIVELY...JUST A FEW
DEGREES UNDR THE AVERAGES FOR NXT WEEKEND.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
QUESTION OVERNIGHT...WHERE TO PLACE RESTRICTIONS WITH FOG AND HOW
LOW TO GO WITH RESTRICTIONS. USING A COMBINATION OF CURRENT
CONDITIONS... FORECAST SOUNDINGS AND BUFKIT DATA...HAVE DECIDED TO
INCLUDE THE FOG AT ALL PORTS EXCEPT PIT...AGC AND BVI. WITH THE
EXCEPTION OF ZZV AND HLG...WILL GO WITH MVFR RESTRICTIONS
TEMPORARILY LOWERING TO IFR. AT THE PREVIOUS 2 PORTS HAVE DECIDED
ON A TEMPO GROUP OF MVFR. CURRENTLY MGW HAS GONE LIFR...WHICH
FALLS IN LINE WITH SURROUNDING PORTS IN NORTHERN WV. WILL LEAVE
THEM AT LIFR FOR THE REST OF THE NIGHT.
CONTINUING TO RELY ON THE FORECAST SOUNDINGS...ALL PORTS SHOULD SEE
BKN-OVC CU DEVELOP LATER THIS MORNING AND REMAIN THROUGH THE
FORECAST PERIOD. THE CU WILL BE IN THE VFR CAT.
HAVE LOWERED WINDS A BIT FROM PREVIOUS FORECAST...AS THE DEVELOPMENT
OF CU SHOULD PREVENT THE STRONGER WINDS ALOFT FROM MIXING DOWN.
OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
NO WIDESPREAD IFR WEATHER IS PREDICTED. PATTERN BECOMES UNSETTLED
BY TUESDAY NIGHT...WITH A CHANCE OF SHOWERS/THUNDERSTORMS TUESDAY
NIGHT THROUGH THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1153 PM EDT MON AUG 5 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 337 PM EDT MON AUG 5 2013
A WARM FRONT IN THE AREA WILL BRING SHOWERS TO THE REGION TONIGHT
ALONG WITH A FEW THUNDERSTORMS. A WARMER MORE MUGGY DAY IS EXPECTED
ON TUESDAY AS SOUTHWEST LOWER MICHIGAN WILL BE SITUATED IN SOUTHERLY
WINDS. ONLY SCATTERED SHOWERS OR STORMS ARE EXPECTED TUESDAY.
TUESDAY NIGHT A COLD FRONT WILL APPROACH FROM THE WEST WITH CHANCES
FOR SHOWERS AND STORMS INCREASING LATE. WEDNESDAY A COLD FRONT WILL
SWING THROUGH THE STATE BRINGING A GOOD CHANCE FOR MORE SHOWERS AND
STORMS. BY WEDNESDAY EVENING MOST LOCATIONS WILL HAVE SEEN SEVERAL
TENTHS OF AN INCH OF RAINFALL.
&&
.UPDATE...
ISSUED AT 805 PM EDT MON AUG 5 2013
I HAVE SIGNIFICANTLY LOWERED THE CHANCES OF RAIN TONIGHT ACROSS THE
CWA. JUST LOOKING AT THE WATER VAPOR LOOPS SHOWING ALL THAT MID-
LEVEL DRY AIR SURGING OUR WAY FROM WISCONSIN CAUSES ME TO WONDER
WHERE THE RAIN WOULD ACTUALLY COME FROM GIVEN THE PRIMARY
SHORTWAVE THAT WOULD DRIVE IT IN THE FIRST PLACE IS CURRENTLY
COMING THROUGH THE CWA WITH ONLY ISOLATED SHOWERS.
THE RAP MODEL SHOWS THE LOW LEVEL JET RAMPING UP AROUND MIDNIGHT
FROM SBN TO GRR. IF THAT TRULY HAPPENED...SURE IT WOULD INDEED
RAIN BUT GIVEN WHAT THE WATER VAPOR IMAGES SHOW... I AM HAVING A
HARD TIME BUYING INTO THE RAP MODEL. SO I HAVE LOWERED POPS TO
30-40 PCT TONIGHT AND WILL CALL THAT GOOD FOR NOW.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 337 PM EDT MON AUG 5 2013
PRECIPITATION HAS STRUGGLED TO DEVELOP THIS AFTERNOON ACROSS
SOUTHWEST LOWER MICHIGAN. THE LACK OF DEEP MOISTURE IS THE
CULPRIT. MOISTURE SHOULD INCREASE THIS EVENING HOWEVER AND REGIONAL
RADAR LOOPS ARE SHOWING AN INCREASE IN SHOWERS FINALLY OVER CENTRAL
LOWER MICHIGAN. THINKING SHOWERS ARE LIKELY TONIGHT WITH A FEW
EMBEDDED STORMS NOT OUT OF THE QUESTION. BOTH THE NSSL AND SPC 12Z
WRF RUNS BRING A DECENT AMOUNT OF PRECIP ACROSS THE FORECAST AREA
TONIGHT. BOTH THE GFS AND NAM SHOW A SMALL LLJ SLIDING ACROSS THE
AREA COINCIDING WITH A BURST OF 850MB MOISTURE TRANSPORT. NEITHER
ARE IMPRESSIVE BUT SHOULD BE ENOUGH TO GENERATE PRECIPITATION.
TUESDAY...AS HAS BEEN THOUGHT THE LAST DAY OR SO SHOULD BE A BIT OF
A LULL IN THE PRECIPITATION AS THE AREA WILL BE IN THE WARM SECTOR.
NOT MUCH OF A FOCUS FOR SHOWERS AND STORMS...BUT INSTABILITY WILL
BUILD WITH A LOW LEVEL MOISTURE RETURN AND SOME SUN BREAKING OUT.
SURFACE FLOW LOOKS TO BE DIVERGENT OFF THE LAKE WHICH IS USUALLY NOT
CONDUCIVE FOR MUCH IN THE WAY OF PRECIP. GIVEN THE INSTABILITY IN
PLACE THOUGH WILL CONTINUE THE 20/30 POPS.
TUESDAY NIGHT INTO WEDNESDAY WILL BE THE MOST LIKELY TIME FRAME FOR
SHOWERS AND STORMS AS A COLD FRONT DRIVES INTO DEEP MOISTURE.
PRECIPITABLE WATER VALUES WILL RISE INTO THE 1.5 TO 1.6 INCH RANGE.
THESE VALUES WHILE NOT HIGH BY AUGUST STANDARDS ARE MUCH HIGHER
THAN WE HAVE SEEN THE LAST FEW DAYS. THERE WILL LIKELY BE SOME
UPSTREAM CONVECTION THAT SPILLS INTO THE AREA LATE TUESDAY NIGHT
WEDNESDAY MORNING ALONG AND AHEAD OF THE COLD FRONT. THE FRONT WILL
BE IN THE FAR SOUTHEAST CWA TOWARD BTL/LAN AND JXN WEDNESDAY
AFTERNOON. NOT OUT OF THE QUESTION TO SEE SOME STRONG STORMS IN THIS
AREA THEN...BUT GIVEN CLOUDS AND LIKELY PRECIP IN THE AREA NOT
THINKING WE HAVE A SIGNIFICANT SEVERE STORM CHANCE. OVERALL THE LOW
LEVEL JET THROUGH THIS TIME FRAME IS FAIRLY WEAK AS WELL. IF THERE
IS A TIME FRAME TO KEEP AN EYE ON THOUGH IT WILL BE WEDNESDAY
AFTERNOON IN THE SOUTHEAST CWA.
WEDNESDAY NIGHT CLOUDS AND PRECIPITATION SHOULD SWEEP SOUTHEAST
QUICKLY WITH COOLER AND DRIER AIR ADVECTING IN.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 337 PM EDT MON AUG 5 2013
UPPER LOW OVER ONTARIO WILL PLAY A ROLE IN OUR WX FOR THE FIRST PART
OF THE PERIOD. INITIALLY...SFC HIGH PRESSURE WILL BE CENTERED OVER
LOWER MICHIGAN BUT THEN DRIFT EAST THURSDAY NIGHT ALLOWING LOW
PRESSURE IN THE SOUTHERN PLAINS TO MOVE TOWARD THE OHIO VALLEY.
CONFIDENCE ISN/T HIGH THAT THE LOW WILL MOVE CLOSE ENOUGH TO THE CWA
TO PRODUCE RAIN BUT MIGHT IF THE FARTHER NORTH GFS SOLUTION
VERIFIES. THE WEAKER ECMWF RENDERS THE CWA DRY THROUGH FRIDAY
COURTESY OF A MUCH WEAKER LOW. AS A RESULT...THE PUSH OF COLD AIR
BEHIND THE TRAILING COLD FRONT ISN/T AS STRONG WITH THE ECMWF AS IT
IS WITH THE GFS. GIVEN THE ABUNDANT COLD AIR INTRUSIONS INTO THE CWA
THIS SUMMER IT WOULD BE EASY TO SIDE WITH THE COLDER GFS. HOWEVER
BOTH THE AO AND NAO ARE TRENDING POSITIVE DURING THAT TIME WHICH
SUGGESTS TO ME THAT THE COLD AIR PUNCH MIGHT NOT BE AS STRONG.
NEXT WEEKEND LOOKS PLEASANT WITH SUNSHINE AND HIGHS IN THE MID 70S.
NEXT CHANCE OF RAIN IS VERY LATE IN THE WEEKEND INTO EARLY NEXT WEEK
WITH THE ARRIVAL OF ANOTHER SHORT WAVE. GIVEN THE NW FLOW ALOFT...WE
DON/T ANTICIPATE ANY HEAVY RAIN EVENTS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1152 PM EDT MON AUG 5 2013
AS I WAS THINKING AT 6 PM... THE LOW CLOUDS WILL COME IN FROM
WISCONSIN OVERNIGHT BRINGING IFR CIGS ACROSS THE AREA THAT WILL
NOT LIFT UNTIL LATE MORNING OR EARLY AFTERNOON TO TUESDAY.
THE REAL QUESTION IS WILL THERE BE SHOWERS OVERNIGHT... ENOUGH TO
LOWER THE VISIBILITIES THAT IS? GIVEN THE WATER VAPOR IMAGE LOOPS
SHOWING SO MUCH MID-LEVEL DRY AIR.... AND SEEING RAP AND NAM 00Z
MODEL RUN SOUNDINGS SHOWING SO MUCH DRY AIR ABOVE 700 MB THROUGH
THE NIGHT... EVEN SOUTH OF INTERSTATE 94... IT IS HARD TO IMAGE
ANYTHING TO SIGNIFICANT DEVELOPING. WHAT EVER DOES HAPPEN.. ARE
MORE LIKELY SOUTH OF INTERSTATE 96... SINCE THAT AREA IS CLOSER
THE TO BETTER MOISTURE AND BETTER LOW LEVEL INFLOW. I FEATURES
SHOWERS OVER THE SOUTHERN TAF SITES ONLY ON THE 06Z TAF SET.
&&
.MARINE...
ISSUED AT 337 PM EDT MON AUG 5 2013
A SOUTHEAST TO SOUTH WIND WILL PICK UP THIS EVENING IN ADVANCE OF A
WARM FRONT. THE GRADIENT SLACKENS OFF LATE...SO EXPECTING WAVES TO
COME UP INTO THE 1-3/2-4 FOOT RANGE UP NORTH BEFORE SUBSIDING A BIT.
THE GRADIENT REMAINS SOMEWHAT SLACK ON TUESDAY WITH WAVES REMAINING
IN THE 1-3 FOOT RANGE IN A WARM AIR ADVECTION SOUTHERLY FLOW REGIME.
THE GRADIENT TIGHTENS AGAIN TUESDAY NIGHT AHEAD OF A COLD FRONT AND
WAVES UP NEAR THE POINTS WILL PUSH TOWARDS 2-4 FEET AGAIN. WEDNESDAY
THE COLD FRONT PASSES WITH WAVES INCREASE IN NORTHERLY FLOW COLD AIR
ADVECTION BEHIND THE FRONT. THE WINDS AND WAVES WILL COME UP
CONSIDERABLY DURING THE AFTERNOON WITH SMALL CRAFT ADVISORIES AND
BEACH HAZARDS STATEMENTS MOST LIKELY NEEDED.
&&
.HYDROLOGY...
ISSUED AT 337 PM EDT MON AUG 5 2013
RIVERS REMAIN AT NORMAL/WITHIN BANK LEVELS TODAY ACROSS SOUTHWEST
LOWER MICHIGAN. RAINFALL IS EXPECTED FROM TONIGHT INTO WEDNESDAY
EVENING. TONIGHT/S RAIN WILL LIKELY BE ON THE ORDER OF 0.10 TO 0.50
OF AN INCH. TONIGHT/S RAIN SHOULD INFILTRATE/RUNOFF WITHOUT MUCH
ISSUE. ADDITIONAL RAINFALL IS EXPECTED FROM TUESDAY NIGHT INTO
WEDNESDAY. THIS PRECIPITATION COULD BE HEAVIER ON THE ORDER OF A
HALF INCH TO AN INCH. GIVEN THE LOW RIVER FLOWS AT THIS POINT...NOT
EXPECTING MUCH ISSUE FROM THIS RAIN EITHER IF WE INDEED SEE THAT
MUCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...93
AVIATION...WDM
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
804 PM EDT MON AUG 5 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 337 PM EDT MON AUG 5 2013
A WARM FRONT IN THE AREA WILL BRING SHOWERS TO THE REGION TONIGHT
ALONG WITH A FEW THUNDERSTORMS. A WARMER MORE MUGGY DAY IS EXPECTED
ON TUESDAY AS SOUTHWEST LOWER MICHIGAN WILL BE SITUATED IN SOUTHERLY
WINDS. ONLY SCATTERED SHOWERS OR STORMS ARE EXPECTED TUESDAY.
TUESDAY NIGHT A COLD FRONT WILL APPROACH FROM THE WEST WITH CHANCES
FOR SHOWERS AND STORMS INCREASING LATE. WEDNESDAY A COLD FRONT WILL
SWING THROUGH THE STATE BRINGING A GOOD CHANCE FOR MORE SHOWERS AND
STORMS. BY WEDNESDAY EVENING MOST LOCATIONS WILL HAVE SEEN SEVERAL
TENTHS OF AN INCH OF RAINFALL.
&&
.UPDATE...
ISSUED AT 805 PM EDT MON AUG 5 2013
I HAVE SIGNIFICANTLY LOWERED THE CHANCES OF RAIN TONIGHT ACROSS THE
CWA. JUST LOOKING AT THE WATER VAPOR LOOPS SHOWING ALL THAT MID-
LEVEL DRY AIR SURGING OUR WAY FROM WISCONSIN CAUSES ME TO WONDER
WHERE THE RAIN WOULD ACTUALLY COME FROM GIVEN THE PRIMARY
SHORTWAVE THAT WOULD DRIVE IT IN THE FIRST PLACE IS CURRENTLY
COMING THROUGH THE CWA WITH ONLY ISOLATED SHOWERS.
THE RAP MODEL SHOWS THE LOW LEVEL JET RAMPING UP AROUND MIDNIGHT
FROM SBN TO GRR. IF THAT TRULY HAPPENED...SURE IT WOULD INDEED
RAIN BUT GIVEN WHAT THE WATER VAPOR IMAGES SHOW... I AM HAVING A
HARD TIME BUYING INTO THE RAP MODEL. SO I HAVE LOWERED POPS TO
30-40 PCT TONIGHT AND WILL CALL THAT GOOD FOR NOW.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 337 PM EDT MON AUG 5 2013
PRECIPITATION HAS STRUGGLED TO DEVELOP THIS AFTERNOON ACROSS
SOUTHWEST LOWER MICHIGAN. THE LACK OF DEEP MOISTURE IS THE
CULPRIT. MOISTURE SHOULD INCREASE THIS EVENING HOWEVER AND REGIONAL
RADAR LOOPS ARE SHOWING AN INCREASE IN SHOWERS FINALLY OVER CENTRAL
LOWER MICHIGAN. THINKING SHOWERS ARE LIKELY TONIGHT WITH A FEW
EMBEDDED STORMS NOT OUT OF THE QUESTION. BOTH THE NSSL AND SPC 12Z
WRF RUNS BRING A DECENT AMOUNT OF PRECIP ACROSS THE FORECAST AREA
TONIGHT. BOTH THE GFS AND NAM SHOW A SMALL LLJ SLIDING ACROSS THE
AREA COINCIDING WITH A BURST OF 850MB MOISTURE TRANSPORT. NEITHER
ARE IMPRESSIVE BUT SHOULD BE ENOUGH TO GENERATE PRECIPITATION.
TUESDAY...AS HAS BEEN THOUGHT THE LAST DAY OR SO SHOULD BE A BIT OF
A LULL IN THE PRECIPITATION AS THE AREA WILL BE IN THE WARM SECTOR.
NOT MUCH OF A FOCUS FOR SHOWERS AND STORMS...BUT INSTABILITY WILL
BUILD WITH A LOW LEVEL MOISTURE RETURN AND SOME SUN BREAKING OUT.
SURFACE FLOW LOOKS TO BE DIVERGENT OFF THE LAKE WHICH IS USUALLY NOT
CONDUCIVE FOR MUCH IN THE WAY OF PRECIP. GIVEN THE INSTABILITY IN
PLACE THOUGH WILL CONTINUE THE 20/30 POPS.
TUESDAY NIGHT INTO WEDNESDAY WILL BE THE MOST LIKELY TIME FRAME FOR
SHOWERS AND STORMS AS A COLD FRONT DRIVES INTO DEEP MOISTURE.
PRECIPITABLE WATER VALUES WILL RISE INTO THE 1.5 TO 1.6 INCH RANGE.
THESE VALUES WHILE NOT HIGH BY AUGUST STANDARDS ARE MUCH HIGHER
THAN WE HAVE SEEN THE LAST FEW DAYS. THERE WILL LIKELY BE SOME
UPSTREAM CONVECTION THAT SPILLS INTO THE AREA LATE TUESDAY NIGHT
WEDNESDAY MORNING ALONG AND AHEAD OF THE COLD FRONT. THE FRONT WILL
BE IN THE FAR SOUTHEAST CWA TOWARD BTL/LAN AND JXN WEDNESDAY
AFTERNOON. NOT OUT OF THE QUESTION TO SEE SOME STRONG STORMS IN THIS
AREA THEN...BUT GIVEN CLOUDS AND LIKELY PRECIP IN THE AREA NOT
THINKING WE HAVE A SIGNIFICANT SEVERE STORM CHANCE. OVERALL THE LOW
LEVEL JET THROUGH THIS TIME FRAME IS FAIRLY WEAK AS WELL. IF THERE
IS A TIME FRAME TO KEEP AN EYE ON THOUGH IT WILL BE WEDNESDAY
AFTERNOON IN THE SOUTHEAST CWA.
WEDNESDAY NIGHT CLOUDS AND PRECIPITATION SHOULD SWEEP SOUTHEAST
QUICKLY WITH COOLER AND DRIER AIR ADVECTING IN.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 337 PM EDT MON AUG 5 2013
UPPER LOW OVER ONTARIO WILL PLAY A ROLE IN OUR WX FOR THE FIRST PART
OF THE PERIOD. INITIALLY...SFC HIGH PRESSURE WILL BE CENTERED OVER
LOWER MICHIGAN BUT THEN DRIFT EAST THURSDAY NIGHT ALLOWING LOW
PRESSURE IN THE SOUTHERN PLAINS TO MOVE TOWARD THE OHIO VALLEY.
CONFIDENCE ISN/T HIGH THAT THE LOW WILL MOVE CLOSE ENOUGH TO THE CWA
TO PRODUCE RAIN BUT MIGHT IF THE FARTHER NORTH GFS SOLUTION
VERIFIES. THE WEAKER ECMWF RENDERS THE CWA DRY THROUGH FRIDAY
COURTESY OF A MUCH WEAKER LOW. AS A RESULT...THE PUSH OF COLD AIR
BEHIND THE TRAILING COLD FRONT ISN/T AS STRONG WITH THE ECMWF AS IT
IS WITH THE GFS. GIVEN THE ABUNDANT COLD AIR INTRUSIONS INTO THE CWA
THIS SUMMER IT WOULD BE EASY TO SIDE WITH THE COLDER GFS. HOWEVER
BOTH THE AO AND NAO ARE TRENDING POSITIVE DURING THAT TIME WHICH
SUGGESTS TO ME THAT THE COLD AIR PUNCH MIGHT NOT BE AS STRONG.
NEXT WEEKEND LOOKS PLEASANT WITH SUNSHINE AND HIGHS IN THE MID 70S.
NEXT CHANCE OF RAIN IS VERY LATE IN THE WEEKEND INTO EARLY NEXT WEEK
WITH THE ARRIVAL OF ANOTHER SHORT WAVE. GIVEN THE NW FLOW ALOFT...WE
DON/T ANTICIPATE ANY HEAVY RAIN EVENTS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 728 PM EDT MON AUG 5 2013
I HAVE A HIGH AMOUNT OF CONFIDENCE THAT CIGS WILL GO IFR ACROSS
ALL OF THE TAF SITES BY 09Z OR SO. THE WARMER AND MORE MOIST AIR
OVER IOWA...WESTERN ILLINOIS AND SOUTHWEST WISCONSIN IS HEAD THIS
WAY. AT 23Z MOST OF THE OBSERVATION SITES ACROSS EASTERN IOWA AND SOUTHERN
WISCONSIN HAVE IFR OR MVFR CIGS...IT IS THAT AREA I AM WATCHING
MOVE OUR WAY OVERNIGHT. THIS WILL BE SLOW TO LEAVE TUESDAY.
THE QUESTION OF RAINFALL IS A MUCH HARDER QUESTION TO ANSWER SINCE
A QUICK LOOK AT THE WATER VAPOR LOOPS SHOWS A LARGE AREA OF MID
LEVEL DRY AIR ALREADY NOSING INTO WESTERN LOWER MICHIGAN. THAT
WOULD SUGGEST TO ME THE DEEP MOISTURE WILL STAY SOUTH OF OUR AREA
AND LARGELY KILL ANY RISK OF RAINFALL TONIGHT. HOWEVER THE HOURS
UPDATES OF THE RAP MODEL LIKE THE IDEA OF A LOW LEVEL JET RAMPING
UP AROUND 06Z FOCUSING ON THE SOUTHWEST SECTIONS OF LOWER
MICHIGAN. IF THAT DOES HAPPEN THERE COULD STILL BE A DECENT RAIN
EVENT LATER TONIGHT OVER THE TAF SITES. FOR NOW I INCLUDED IT IN
THE FORECAST BUT I HAVE TO SAY IT IS A 50/50 QUESTION IF IT WILL
RAIN AT ALL TONIGHT OVER SOUTHWEST MICHIGAN.
&&
.MARINE...
ISSUED AT 337 PM EDT MON AUG 5 2013
A SOUTHEAST TO SOUTH WIND WILL PICK UP THIS EVENING IN ADVANCE OF A
WARM FRONT. THE GRADIENT SLACKENS OFF LATE...SO EXPECTING WAVES TO
COME UP INTO THE 1-3/2-4 FOOT RANGE UP NORTH BEFORE SUBSIDING A BIT.
THE GRADIENT REMAINS SOMEWHAT SLACK ON TUESDAY WITH WAVES REMAINING
IN THE 1-3 FOOT RANGE IN A WARM AIR ADVECTION SOUTHERLY FLOW REGIME.
THE GRADIENT TIGHTENS AGAIN TUESDAY NIGHT AHEAD OF A COLD FRONT AND
WAVES UP NEAR THE POINTS WILL PUSH TOWARDS 2-4 FEET AGAIN. WEDNESDAY
THE COLD FRONT PASSES WITH WAVES INCREASE IN NORTHERLY FLOW COLD AIR
ADVECTION BEHIND THE FRONT. THE WINDS AND WAVES WILL COME UP
CONSIDERABLY DURING THE AFTERNOON WITH SMALL CRAFT ADVISORIES AND
BEACH HAZARDS STATEMENTS MOST LIKELY NEEDED.
&&
.HYDROLOGY...
ISSUED AT 337 PM EDT MON AUG 5 2013
RIVERS REMAIN AT NORMAL/WITHIN BANK LEVELS TODAY ACROSS SOUTHWEST
LOWER MICHIGAN. RAINFALL IS EXPECTED FROM TONIGHT INTO WEDNESDAY
EVENING. TONIGHT/S RAIN WILL LIKELY BE ON THE ORDER OF 0.10 TO 0.50
OF AN INCH. TONIGHT/S RAIN SHOULD INFILTRATE/RUNOFF WITHOUT MUCH
ISSUE. ADDITIONAL RAINFALL IS EXPECTED FROM TUESDAY NIGHT INTO
WEDNESDAY. THIS PRECIPITATION COULD BE HEAVIER ON THE ORDER OF A
HALF INCH TO AN INCH. GIVEN THE LOW RIVER FLOWS AT THIS POINT...NOT
EXPECTING MUCH ISSUE FROM THIS RAIN EITHER IF WE INDEED SEE THAT
MUCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...93
AVIATION...WDM
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
728 PM EDT MON AUG 5 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 337 PM EDT MON AUG 5 2013
A WARM FRONT IN THE AREA WILL BRING SHOWERS TO THE REGION TONIGHT
ALONG WITH A FEW THUNDERSTORMS. A WARMER MORE MUGGY DAY IS EXPECTED
ON TUESDAY AS SOUTHWEST LOWER MICHIGAN WILL BE SITUATED IN SOUTHERLY
WINDS. ONLY SCATTERED SHOWERS OR STORMS ARE EXPECTED TUESDAY.
TUESDAY NIGHT A COLD FRONT WILL APPROACH FROM THE WEST WITH CHANCES
FOR SHOWERS AND STORMS INCREASING LATE. WEDNESDAY A COLD FRONT WILL
SWING THROUGH THE STATE BRINGING A GOOD CHANCE FOR MORE SHOWERS AND
STORMS. BY WEDNESDAY EVENING MOST LOCATIONS WILL HAVE SEEN SEVERAL
TENTHS OF AN INCH OF RAINFALL.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 337 PM EDT MON AUG 5 2013
PRECIPITATION HAS STRUGGLED TO DEVELOP THIS AFTERNOON ACROSS
SOUTHWEST LOWER MICHIGAN. THE LACK OF DEEP MOISTURE IS THE
CULPRIT. MOISTURE SHOULD INCREASE THIS EVENING HOWEVER AND REGIONAL
RADAR LOOPS ARE SHOWING AN INCREASE IN SHOWERS FINALLY OVER CENTRAL
LOWER MICHIGAN. THINKING SHOWERS ARE LIKELY TONIGHT WITH A FEW
EMBEDDED STORMS NOT OUT OF THE QUESTION. BOTH THE NSSL AND SPC 12Z
WRF RUNS BRING A DECENT AMOUNT OF PRECIP ACROSS THE FORECAST AREA
TONIGHT. BOTH THE GFS AND NAM SHOW A SMALL LLJ SLIDING ACROSS THE
AREA COINCIDING WITH A BURST OF 850MB MOISTURE TRANSPORT. NEITHER
ARE IMPRESSIVE BUT SHOULD BE ENOUGH TO GENERATE PRECIPITATION.
TUESDAY...AS HAS BEEN THOUGHT THE LAST DAY OR SO SHOULD BE A BIT OF
A LULL IN THE PRECIPITATION AS THE AREA WILL BE IN THE WARM SECTOR.
NOT MUCH OF A FOCUS FOR SHOWERS AND STORMS...BUT INSTABILITY WILL
BUILD WITH A LOW LEVEL MOISTURE RETURN AND SOME SUN BREAKING OUT.
SURFACE FLOW LOOKS TO BE DIVERGENT OFF THE LAKE WHICH IS USUALLY NOT
CONDUCIVE FOR MUCH IN THE WAY OF PRECIP. GIVEN THE INSTABILITY IN
PLACE THOUGH WILL CONTINUE THE 20/30 POPS.
TUESDAY NIGHT INTO WEDNESDAY WILL BE THE MOST LIKELY TIME FRAME FOR
SHOWERS AND STORMS AS A COLD FRONT DRIVES INTO DEEP MOISTURE.
PRECIPITABLE WATER VALUES WILL RISE INTO THE 1.5 TO 1.6 INCH RANGE.
THESE VALUES WHILE NOT HIGH BY AUGUST STANDARDS ARE MUCH HIGHER
THAN WE HAVE SEEN THE LAST FEW DAYS. THERE WILL LIKELY BE SOME
UPSTREAM CONVECTION THAT SPILLS INTO THE AREA LATE TUESDAY NIGHT
WEDNESDAY MORNING ALONG AND AHEAD OF THE COLD FRONT. THE FRONT WILL
BE IN THE FAR SOUTHEAST CWA TOWARD BTL/LAN AND JXN WEDNESDAY
AFTERNOON. NOT OUT OF THE QUESTION TO SEE SOME STRONG STORMS IN THIS
AREA THEN...BUT GIVEN CLOUDS AND LIKELY PRECIP IN THE AREA NOT
THINKING WE HAVE A SIGNIFICANT SEVERE STORM CHANCE. OVERALL THE LOW
LEVEL JET THROUGH THIS TIME FRAME IS FAIRLY WEAK AS WELL. IF THERE
IS A TIME FRAME TO KEEP AN EYE ON THOUGH IT WILL BE WEDNESDAY
AFTERNOON IN THE SOUTHEAST CWA.
WEDNESDAY NIGHT CLOUDS AND PRECIPITATION SHOULD SWEEP SOUTHEAST
QUICKLY WITH COOLER AND DRIER AIR ADVECTING IN.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 337 PM EDT MON AUG 5 2013
UPPER LOW OVER ONTARIO WILL PLAY A ROLE IN OUR WX FOR THE FIRST PART
OF THE PERIOD. INITIALLY...SFC HIGH PRESSURE WILL BE CENTERED OVER
LOWER MICHIGAN BUT THEN DRIFT EAST THURSDAY NIGHT ALLOWING LOW
PRESSURE IN THE SOUTHERN PLAINS TO MOVE TOWARD THE OHIO VALLEY.
CONFIDENCE ISN/T HIGH THAT THE LOW WILL MOVE CLOSE ENOUGH TO THE CWA
TO PRODUCE RAIN BUT MIGHT IF THE FARTHER NORTH GFS SOLUTION
VERIFIES. THE WEAKER ECMWF RENDERS THE CWA DRY THROUGH FRIDAY
COURTESY OF A MUCH WEAKER LOW. AS A RESULT...THE PUSH OF COLD AIR
BEHIND THE TRAILING COLD FRONT ISN/T AS STRONG WITH THE ECMWF AS IT
IS WITH THE GFS. GIVEN THE ABUNDANT COLD AIR INTRUSIONS INTO THE CWA
THIS SUMMER IT WOULD BE EASY TO SIDE WITH THE COLDER GFS. HOWEVER
BOTH THE AO AND NAO ARE TRENDING POSITIVE DURING THAT TIME WHICH
SUGGESTS TO ME THAT THE COLD AIR PUNCH MIGHT NOT BE AS STRONG.
NEXT WEEKEND LOOKS PLEASANT WITH SUNSHINE AND HIGHS IN THE MID 70S.
NEXT CHANCE OF RAIN IS VERY LATE IN THE WEEKEND INTO EARLY NEXT WEEK
WITH THE ARRIVAL OF ANOTHER SHORT WAVE. GIVEN THE NW FLOW ALOFT...WE
DON/T ANTICIPATE ANY HEAVY RAIN EVENTS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 728 PM EDT MON AUG 5 2013
I HAVE A HIGH AMOUNT OF CONFIDENCE THAT CIGS WILL GO IFR ACROSS
ALL OF THE TAF SITES BY 09Z OR SO. THE WARMER AND MORE MOIST AIR
OVER IOWA...WESTERN ILLINOIS AND SOUTHWEST WISCONSIN IS HEAD THIS
WAY. AT 23Z MOST OF THE OBSERVATION SITES ACROSS EASTERN IOWA AND SOUTHERN
WISCONSIN HAVE IFR OR MVFR CIGS...IT IS THAT AREA I AM WATCHING
MOVE OUR WAY OVERNIGHT. THIS WILL BE SLOW TO LEAVE TUESDAY.
THE QUESTION OF RAINFALL IS A MUCH HARDER QUESTION TO ANSWER SINCE
A QUICK LOOK AT THE WATER VAPOR LOOPS SHOWS A LARGE AREA OF MID
LEVEL DRY AIR ALREADY NOSING INTO WESTERN LOWER MICHIGAN. THAT
WOULD SUGGEST TO ME THE DEEP MOISTURE WILL STAY SOUTH OF OUR AREA
AND LARGELY KILL ANY RISK OF RAINFALL TONIGHT. HOWEVER THE HOURS
UPDATES OF THE RAP MODEL LIKE THE IDEA OF A LOW LEVEL JET RAMPING
UP AROUND 06Z FOCUSING ON THE SOUTHWEST SECTIONS OF LOWER
MICHIGAN. IF THAT DOES HAPPEN THERE COULD STILL BE A DECENT RAIN
EVENT LATER TONIGHT OVER THE TAF SITES. FOR NOW I INCLUDED IT IN
THE FORECAST BUT I HAVE TO SAY IT IS A 50/50 QUESTION IF IT WILL
RAIN AT ALL TONIGHT OVER SOUTHWEST MICHIGAN.
&&
.MARINE...
ISSUED AT 337 PM EDT MON AUG 5 2013
A SOUTHEAST TO SOUTH WIND WILL PICK UP THIS EVENING IN ADVANCE OF A
WARM FRONT. THE GRADIENT SLACKENS OFF LATE...SO EXPECTING WAVES TO
COME UP INTO THE 1-3/2-4 FOOT RANGE UP NORTH BEFORE SUBSIDING A BIT.
THE GRADIENT REMAINS SOMEWHAT SLACK ON TUESDAY WITH WAVES REMAINING
IN THE 1-3 FOOT RANGE IN A WARM AIR ADVECTION SOUTHERLY FLOW REGIME.
THE GRADIENT TIGHTENS AGAIN TUESDAY NIGHT AHEAD OF A COLD FRONT AND
WAVES UP NEAR THE POINTS WILL PUSH TOWARDS 2-4 FEET AGAIN. WEDNESDAY
THE COLD FRONT PASSES WITH WAVES INCREASE IN NORTHERLY FLOW COLD AIR
ADVECTION BEHIND THE FRONT. THE WINDS AND WAVES WILL COME UP
CONSIDERABLY DURING THE AFTERNOON WITH SMALL CRAFT ADVISORIES AND
BEACH HAZARDS STATEMENTS MOST LIKELY NEEDED.
&&
.HYDROLOGY...
ISSUED AT 337 PM EDT MON AUG 5 2013
RIVERS REMAIN AT NORMAL/WITHIN BANK LEVELS TODAY ACROSS SOUTHWEST
LOWER MICHIGAN. RAINFALL IS EXPECTED FROM TONIGHT INTO WEDNESDAY
EVENING. TONIGHT/S RAIN WILL LIKELY BE ON THE ORDER OF 0.10 TO 0.50
OF AN INCH. TONIGHT/S RAIN SHOULD INFILTRATE/RUNOFF WITHOUT MUCH
ISSUE. ADDITIONAL RAINFALL IS EXPECTED FROM TUESDAY NIGHT INTO
WEDNESDAY. THIS PRECIPITATION COULD BE HEAVIER ON THE ORDER OF A
HALF INCH TO AN INCH. GIVEN THE LOW RIVER FLOWS AT THIS POINT...NOT
EXPECTING MUCH ISSUE FROM THIS RAIN EITHER IF WE INDEED SEE THAT
MUCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...93
AVIATION...WDM
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
716 AM EDT SUN AUG 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 454 AM EDT SUN AUG 4 2013
NW FLOW ALOFT REMAINS IN PLACE BUT HEIGHTS ARE FLATTER ACROSS LK
SUPERIOR REGION COMPARED TO YESTERDAY. WV LOOP SHOWS RIBBON OF
DRYING WITH ENHANCED MOISTURE STAYING MOSTLY NORTH AND EAST OF
UPPER MICHIGAN. FLOW BECOMES MORE ZONAL FM PACIFIC NORTHWEST
THROUGH NORTHERN PLAINS INTO SOUTHERN PORTIONS OF ALBERTA AND
SASKATCHEWAN. MORE FORMIDABLE SHORTWAVE IS LOCATED HERE AND THAT
WAVE ALONG WITH SFC TROUGH AND ASSOCIATED WARM/MOIST ADVECTION IS
HELPING TO GENERATE CLUSTERS OF SHRA/TSRA FM SOUTHERN SASKATCHEWAN
THROUGH WESTERN DAKOTAS. THE SHORTWAVE AND SFC TROUGH APPROACH UPPER
LAKES REGION LATE TONIGHT AND COULD BRING SOME SHOWERS TO THE AREA.
MORE ON THAT LATER ON.
CURRENTLY OVER UPPER MICHIGAN...1026MB HIGH PRESSURE RIDGE CENTERED
OVER CENTRAL MINNESOTA IS TRYING TO RIDGE ACROSS WESTERN CWA. TEMPS
ARE AS COLD AS LOWER 40S THERE BUT ARE STILL INTO THE 50S ALONG LK
SUPERIOR AND OVER EASTERN HALF OF CWA. COOL/MOIST AIR AND LIGHT
WINDS OVER WEST RESULTING IN SOME FOG AS SEEN IN VSBY LESS THAN 3SM
AT IWD AND EGV THROUGH THE NIGHT. OTHERWISE...SKIES ARE MAINLY CLEAR
THOUGH STRATOCU IS HANGING TOUGH IN THE EAST CLOSER TO H9-H8 THERMAL
TROUGH. UPSTREAM SOUNDING AT CYPL SHOWED WELL MIXED LOWER BLYR WITH
SHALLOW LAYER OF MOISTURE AROUND 800MB/6KFT AND SUBSIDENCE INVERSION
BETWEEN H8-H7. CONVECTIVE TEMPS PRETTY LOW OVR CWA TODAY...MID-UPR
60S...SO THINK THIS MOISTURE WILL TURN INTO FAIRLY DECENT CU DECK BY
EARLY AFTN. SKIES COULD TURN MOSTLY CLOUDY FOR A TIME WHERE LAKE
BREEZE CONVERGENCE IS STRONGEST OVR CNTRL UPR MICHIGAN. GIVEN MORE
UNFAVORABLE LARGE SCALE SETUP FOR PRECIP WITH NO REAL SHORTWAVES
MOVING ACROSS AND WITH THERMAL TROUGHING EXITING THROUGH AFTN ALONG
WITH NOT AS MUCH MOISTURE DEPTH AS YESTERDAY...WILL GO WITH DRY
FORECAST TODAY. PER MODELED RADAR REFLECTIVITY ONLY THE LOCAL
RUM-WRF MODEL INDICATES POSSIBLY SEEING A SHRA WHILE HRRR SHOWS
LITTLE IN WAY OF SHRA DEVELOPMENT.
ATTN TONIGHT IS ON THE SHORTWAVE OVER SOUTHERN SASKATCHEWAN. EXPECT
THIS WAVE TO PUSH ACROSS NORTH DAKOTA THIS EVENING AND INTO NORTHEAST
MINNESOTA LATE TONIGHT. ANOTHER WAVE AND UPPER JETLET CURRENTLY
LIFTING ACROSS WESTERN MONTANA SLIDES TO CENTRAL MINNESOTA LATER
TONIGHT. SFC-H85 TROUGH WORKS EAST INTO MINNESOTA BY LATE TONIGHT.
MAINLY H7 MOISTURE ADVECTION AND FRONTOGENESIS AHEAD OF THE WAVES
ALONG WITH H85 TEMPERATURE ADVECTION WILL BE MAIN SUPPORT FOR SHRA
TONIGHT. A LOT OF TSRA CURRENTLY OVER DAKOTAS BUT EDGE OF 1-6KM
MUCAPE STAYS WELL TO THE SOUTHWEST OF UPR MICHIGAN TO NOT INCLUDE
TSRA. GFS/NAM/ECMWF/GEM IN GENERAL AGREEMENT ABOUT TONIGHT...BUT
NAM AND ASSOCIATED HIGHER RESOLUTION MODELS THAT ARE INITIALIZED OFF
OF IT...ARE MORE AGGRESSIVE WITH SHRA DEVELOPMENT OVER UPR MICHIGAN
OVERNIGHT TONIGHT. DO THINK H85-H6 MOISTURE ADVECTION/LIFT AND WARM
AIR ADVECTION AT H85 IS ENOUGH TO INCLUDE SLIGHT CHANCES WORKING
FROM WEST TO CENTRAL CWA. BUMPED POPS UP LATE TO LOWER CHANCE TOWARD
OVER FAR SW...VCNTY OF IWD AND IRON RIVER...WITH CLOSER PROXIMITY TO
LARGER SCALE WAVES MOVING INTO THE UPPER LAKES REGION. H7-H5 MOISTURE
SHOULD INCREASE STEADILY FM WEST TO EAST TONIGHT...WHICH WILL AFFECT
MIN TEMPS. COLD SPOT WILL BE INTERIOR EAST CWA /MID 40S MIN TEMPS/
AS LONGER PERIOD OF CLEAR SKIES/MINIMUM OF PWAT RESULTS IN BETTER
RADIATIONAL COOLING. TEMPS OVER FAR WEST WILL ONLY FALL INTO THE MID
50S WITH MORE CLOUD COVER AND INCREASING RETURN FLOW AHEAD OF SFC
TROUGH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 454 AM EDT SUN AUG 4 2013
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT ON THE BIG PICTURE THRU
THIS WEEK. IN THE MEAN...A TROF IS EXPECTED TO REMAIN IN PLACE
GENERALLY FROM HUDSON BAY VCNTY TO THE GREAT LAKES...NEW ENGLAND AND
SE CANADA. MAIN FEATURE THAT WILL CONTROL THE WEATHER OVER THE UPPER
LAKES DURING THE LONG TERM IS THE ENERGY THAT HAS PEELED OFF THE
DEEP POLAR VORTEX OVER THE WRN ARCTIC AND IS NOW IN THE PROCESS OF
FORMING A MID LEVEL LOW OVER HUDSON BAY. FARTHER N...THE RIDGES OVER
WRN NAMERICA AND BTWN GREENLAND AND BAFFIN ISLAND WILL CONNECT
ACROSS NRN CANADA OVER THE NEXT DAY OR TWO...FORCING THE MID LEVEL
LOW TO MEANDER EVEN FARTHER S DURING THE WEEK. AT SOME POINT...IT
WILL PASS ACROSS THE UPPER GREAT LAKES/NRN ONTARIO LATE THIS WEEK.
END RESULT IS A CONTINUATION OF A GENERAL BELOW NORMAL TEMP REGIME
FOR UPPER MI OVER THE NEXT 7-10DAYS. WHILE SOME DAYS WILL SEE TEMPS
AROUND NORMAL...THE OVERALL PATTERN SUGGESTS THE POTENTIAL FOR SOME
CHILLY DAYS FOR EARLY AUG STANDARDS AS WELL. THIS IS ESPECIALLY TRUE
LATE WEEK WHEN THE MID LEVEL LOW PASSES AND BRINGS ITS ASSOCIATED
COLD AIR INTO THE AREA. AS FOR PCPN...THERE WILL BE INCREASING PCPN
CHANCES MON/TUE AND PROBABLY INTO WED MORNING AS SHORTWAVES EJECT
FROM A PACIFIC NW/SW CANADA TROF AND TRACK E ACROSS THE NRN CONUS
UNDERNEATH THE MID LEVEL LOW. UNSETTLED WEATHER MAY PUSH THRU THE
AREA AGAIN LATE WEEK DEPENDING ON TRACK OF THE MID LEVEL LOW ACROSS
THE UPPER LAKES AND/OR NRN ONTARIO AND DEPENDING ON WHETHER ANY
ADDITIONAL SHORTWAVES ROTATE AROUND THE LOW.
BEGINNING MON...ATTENTION WILL BE ON THE WELL-DEFINED SHORTWAVE
CURRENTLY OVER SRN SASKATCHEWAN. GIVEN THE PRONOUNCED NW FLOW THIS
MORNING OVER THE UPPER LAKES...IT WOULD SEEM THIS WAVE WON`T BE ABLE
TO MAKE A STRONG PUSH E TO UPPER MI. MODELS DO SHOW FLOW BACKING
WITH UPPER MI UNDER WNW FLOW MON...WHICH STILL SHOULD DIRECT THE
SHORTWAVE AND BULK OF FORCING ESE THRU WI AS DEPICTED BY DEEP LAYER
QVECTORS. THE AXIS OF INSTABILITY REMAINS WELL TO THE SW WITH EVEN
THE INSTABILITY GRADIENT TO THE SW OF HERE. THIS ALSO SUPPORTS THE
IDEA OF MAIN AREA OF PCPN PASSING BY TO THE S. THAT SAID...GIVEN THE
WELL-DEFINED LOOK OF THE SHORTWAVE...SOME PCPN WILL PROBABLY STILL
BRUSH UPPER MI MON AS INDICATED BY ALL MODEL GUIDANCE. IN THE END...
PREFER THE MORE LIMITED NORTHWARD PUSH OF PCPN SHOWN BY THE ECMWF
AND THE 4KM HIGH RES NAM NEST GIVEN ABOVE DISCUSSION. WITH
INSTABILITY AND INSTABILITY GRADIENT TO THE SW...THUNDER LOOKS
UNLIKELY AND WON`T BE MENTIONED. IF THERE IS ANY THUNDER...IT
SHOULD ONLY AFFECT AREAS TOWARD THE WI BORDER.
FCST FOR MON NIGHT IS FAIRLY UNCERTAIN. IT WOULD SEEM DRY WEATHER
SHOULD FOLLOW AS SHORTWAVE CONTINUES TO THE ESE. 850MB WAA AND 850MB
WINDS ARE WEAK (10-15KT)...CERTAINLY SUGGESTING MINIMAL POTENTIAL
FOR MORE ORGANIZED PCPN AREAS. HOWEVER...WITH CYCLONIC 850MB FLOW
AND HINTS OF ONE OR TWO SUBTLE TROFS IN THE WIND FIELD...WILL
MAINTAIN SCHC POPS FOR MUCH OF THE AREA THRU THE NIGHT.
ON TUE...UNUSUALLY DEEP MID LEVEL LOW FOR EARLY AUG WILL BE WOBBLING
S ROUGHLY ALONG THE NE MANITOBA/NRN ONTARIO BORDER. AS A RESULT...
FLOW WILL CONTINUE TO BACK ACROSS THE UPPER GREAT LAKES UNDER THE
EXPANDING CIRCULATION AROUND THE LOW. TO THE W...COMBINATION OF A
SHORTWAVE ROTATING AROUND THE MID LEVEL LOW AND A SHORTWAVE PICKED
UP FROM THE PACIFIC NW/SW CANADA WILL LEAD TO AN ORGANIZING COLD
FRONT MOVING ACROSS THE NRN PLAINS TUE. ORGANIZED PCPN ASSOCIATED
WITH FRONT SHOULD REMAIN W OF UPPER MI THRU TUE AFTN. ACROSS UPPER
MI...NAM/GFS SHOW MLCAPE INCREASING TO AROUND 500J/KG TUE. WITH
HINTS OF A SUBTLE SHORTWAVE PASSING ACROSS THE AREA...WILL INCLUDE
LOW CHC POPS FOR SHRA/TSRA.
AS WAS THE CASE YESTERDAY...MODELS STILL SUGGEST TUE NIGHT AS HAVING
THE BEST SHOT OF SHRA/TSRA AS COLD FRONT PASSES ACROSS UPPER MI TUE
NIGHT/WED MORNING. THERE ARE STILL SOME TIMING ISSUES TO SORT OUT AS
THE GFS/NAM HAVE FRONT OVER THE FAR ERN FCST AREA AT 12Z WED WHILE
THE ECMWF/GEM ARE ABOUT 6-9HRS SLOWER. THE TIMING UNCERTAINTY LEADS
TO LOWER CONFIDENCE IN PIN POINTING PERIOD OF HIGHER POPS. TAKING
INTO ACCOUNT GFS/ECMWF GUIDANCE OVER THE LAST DAY OR TWO...WILL
HEDGE FCST SLIGHTLY TOWARD THE SLOWER SOLUTION...WHICH RESULTS IN
HANGING ONTO HIGHER POPS OVER THE E INTO WED MORNING. IN THE WAKE OF
SHORTWAVE/COLD FRONT...DRY WEATHER WILL FOLLOW W TO E DURING THE DAY
WED.
PLENTY OF UNCERTAINTY REMAINS FOR THU/FRI/SAT REGARDING TIMING/TRACK
OF THE UNUSUALLY DEEP MID LEVEL LOW (500MB HEIGHTS MAY BE AROUND 2.5
STANDARD DEVIATIONS BELOW LONG TERM AVG). IF ANYTHING...THE LAST DAY
OR TWO OF GFS/ECMWF MODEL RUNS SUGGEST A TREND FOR A SLIGHTLY SLOWER
PROGRESSION OF THE MID LEVEL LOW ACROSS NRN ONTARIO DURING THE LAST
HALF OF THE WEEK. THIS SLOWER TREND RAISES THE PROSPECT FOR AT LEAST
ONE SHORTWAVE ROTATING AROUND THE LOW TO AFFECT UPPER MI. THE
PREDICTABILITY OF TIMING A WAVE ROTATING AROUND A MID LEVEL LOW 4 TO
6 DAYS OUT IN A MODEL RUN IS VERY LOW. FOR WHAT IT`S WORTH...LATEST
GUIDANCE SUGGESTS A SHORTWAVE MAY ROTATE THRU THE UPPER LAKES FRI...
PROVIDING THE POTENTIAL FOR SOME SHRA. TEMPS WILL TURN COOLER LATE
WEEK. IN FACT...THERE COULD BE AT LEAST 1 DAY OF WELL BELOW NORMAL
TEMPS WITH HIGHS POTENTIALLY ONLY IN THE MID 50S NEAR LAKE SUPERIOR
AND LOW/MID 60S INLAND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 711 AM EDT SUN AUG 4 2013
VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE FORECAST. HIGH
PRESSURE OVERHEAD TODAY RESULTS IN LIGHT WINDS...TAKING ON FAVORED
LAKE BREEZE DIRECTION BY THIS AFTN. MID CLOUDS INCREASE TONIGHT OUT
AHEAD OF APPROACHING DISTURBANCE AND SURFACE TROUGH. COULD BE ENOUGH
LOW-LEVEL MOISTURE ADVECTION TO FORM SOME SHOWERS LATE AT IWD SO
HAVE PUT IN A VCNTY SHRA. AT CMX AND SAW...ANY RAIN SHOULD HOLD OFF
TIL JUST BEYOND TAF PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 454 AM EDT SUN AUG 4 2013
THROUGH THIS FCST PERIOD...WINDS SHOULD BE NO HIGHER THAN 20KT WITH
GENERALLY A WEAK PRESSURE GRADIENT DOMINATING THE UPPER GREAT LAKES.
HOWEVER...WILL NEED TO CONTINUE WATCHING THE MID WEEK PERIOD AS A
PASSING COLD FRONT COULD LEAD TO STRONGER PRE FRONTAL AND ESPECIALLY
POST FRONTAL WINDS IN THE LATE TUE/WED TIME FRAME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...JLA
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
457 AM EDT SUN AUG 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 454 AM EDT SUN AUG 4 2013
NW FLOW ALOFT REMAINS IN PLACE BUT HEIGHTS ARE FLATTER ACROSS LK
SUPERIOR REGION COMPARED TO YESTERDAY. WV LOOP SHOWS RIBBON OF
DRYING WITH ENHANCED MOISTURE STAYING MOSTLY NORTH AND EAST OF
UPPER MICHIGAN. FLOW BECOMES MORE ZONAL FM PACIFIC NORTHWEST
THROUGH NORTHERN PLAINS INTO SOUTHERN PORTIONS OF ALBERTA AND
SASKATCHEWAN. MORE FORMIDABLE SHORTWAVE IS LOCATED HERE AND THAT
WAVE ALONG WITH SFC TROUGH AND ASSOCIATED WARM/MOIST ADVECTION IS
HELPING TO GENERATE CLUSTERS OF SHRA/TSRA FM SOUTHERN SASKATCHEWAN
THROUGH WESTERN DAKOTAS. THE SHORTWAVE AND SFC TROUGH APPROACH UPPER
LAKES REGION LATE TONIGHT AND COULD BRING SOME SHOWERS TO THE AREA.
MORE ON THAT LATER ON.
CURRENTLY OVER UPPER MICHIGAN...1026MB HIGH PRESSURE RIDGE CENTERED
OVER CENTRAL MINNESOTA IS TRYING TO RIDGE ACROSS WESTERN CWA. TEMPS
ARE AS COLD AS LOWER 40S THERE BUT ARE STILL INTO THE 50S ALONG LK
SUPERIOR AND OVER EASTERN HALF OF CWA. COOL/MOIST AIR AND LIGHT
WINDS OVER WEST RESULTING IN SOME FOG AS SEEN IN VSBY LESS THAN 3SM
AT IWD AND EGV THROUGH THE NIGHT. OTHERWISE...SKIES ARE MAINLY CLEAR
THOUGH STRATOCU IS HANGING TOUGH IN THE EAST CLOSER TO H9-H8 THERMAL
TROUGH. UPSTREAM SOUNDING AT CYPL SHOWED WELL MIXED LOWER BLYR WITH
SHALLOW LAYER OF MOISTURE AROUND 800MB/6KFT AND SUBSIDENCE INVERSION
BETWEEN H8-H7. CONVECTIVE TEMPS PRETTY LOW OVR CWA TODAY...MID-UPR
60S...SO THINK THIS MOISTURE WILL TURN INTO FAIRLY DECENT CU DECK BY
EARLY AFTN. SKIES COULD TURN MOSTLY CLOUDY FOR A TIME WHERE LAKE
BREEZE CONVERGENCE IS STRONGEST OVR CNTRL UPR MICHIGAN. GIVEN MORE
UNFAVORABLE LARGE SCALE SETUP FOR PRECIP WITH NO REAL SHORTWAVES
MOVING ACROSS AND WITH THERMAL TROUGHING EXITING THROUGH AFTN ALONG
WITH NOT AS MUCH MOISTURE DEPTH AS YESTERDAY...WILL GO WITH DRY
FORECAST TODAY. PER MODELED RADAR REFLECTIVITY ONLY THE LOCAL
RUM-WRF MODEL INDICATES POSSIBLY SEEING A SHRA WHILE HRRR SHOWS
LITTLE IN WAY OF SHRA DEVELOPMENT.
ATTN TONIGHT IS ON THE SHORTWAVE OVER SOUTHERN SASKATCHEWAN. EXPECT
THIS WAVE TO PUSH ACROSS NORTH DAKOTA THIS EVENING AND INTO NORTHEAST
MINNESOTA LATE TONIGHT. ANOTHER WAVE AND UPPER JETLET CURRENTLY
LIFTING ACROSS WESTERN MONTANA SLIDES TO CENTRAL MINNESOTA LATER
TONIGHT. SFC-H85 TROUGH WORKS EAST INTO MINNESOTA BY LATE TONIGHT.
MAINLY H7 MOISTURE ADVECTION AND FRONTOGENESIS AHEAD OF THE WAVES
ALONG WITH H85 TEMPERATURE ADVECTION WILL BE MAIN SUPPORT FOR SHRA
TONIGHT. A LOT OF TSRA CURRENTLY OVER DAKOTAS BUT EDGE OF 1-6KM
MUCAPE STAYS WELL TO THE SOUTHWEST OF UPR MICHIGAN TO NOT INCLUDE
TSRA. GFS/NAM/ECMWF/GEM IN GENERAL AGREEMENT ABOUT TONIGHT...BUT
NAM AND ASSOCIATED HIGHER RESOLUTION MODELS THAT ARE INITIALIZED OFF
OF IT...ARE MORE AGGRESSIVE WITH SHRA DEVELOPMENT OVER UPR MICHIGAN
OVERNIGHT TONIGHT. DO THINK H85-H6 MOISTURE ADVECTION/LIFT AND WARM
AIR ADVECTION AT H85 IS ENOUGH TO INCLUDE SLIGHT CHANCES WORKING
FROM WEST TO CENTRAL CWA. BUMPED POPS UP LATE TO LOWER CHANCE TOWARD
OVER FAR SW...VCNTY OF IWD AND IRON RIVER...WITH CLOSER PROXIMITY TO
LARGER SCALE WAVES MOVING INTO THE UPPER LAKES REGION. H7-H5 MOISTURE
SHOULD INCREASE STEADILY FM WEST TO EAST TONIGHT...WHICH WILL AFFECT
MIN TEMPS. COLD SPOT WILL BE INTERIOR EAST CWA /MID 40S MIN TEMPS/
AS LONGER PERIOD OF CLEAR SKIES/MINIMUM OF PWAT RESULTS IN BETTER
RADIATIONAL COOLING. TEMPS OVER FAR WEST WILL ONLY FALL INTO THE MID
50S WITH MORE CLOUD COVER AND INCREASING RETURN FLOW AHEAD OF SFC
TROUGH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 454 AM EDT SUN AUG 4 2013
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT ON THE BIG PICTURE THRU
THIS WEEK. IN THE MEAN...A TROF IS EXPECTED TO REMAIN IN PLACE
GENERALLY FROM HUDSON BAY VCNTY TO THE GREAT LAKES...NEW ENGLAND AND
SE CANADA. MAIN FEATURE THAT WILL CONTROL THE WEATHER OVER THE UPPER
LAKES DURING THE LONG TERM IS THE ENERGY THAT HAS PEELED OFF THE
DEEP POLAR VORTEX OVER THE WRN ARCTIC AND IS NOW IN THE PROCESS OF
FORMING A MID LEVEL LOW OVER HUDSON BAY. FARTHER N...THE RIDGES OVER
WRN NAMERICA AND BTWN GREENLAND AND BAFFIN ISLAND WILL CONNECT
ACROSS NRN CANADA OVER THE NEXT DAY OR TWO...FORCING THE MID LEVEL
LOW TO MEANDER EVEN FARTHER S DURING THE WEEK. AT SOME POINT...IT
WILL PASS ACROSS THE UPPER GREAT LAKES/NRN ONTARIO LATE THIS WEEK.
END RESULT IS A CONTINUATION OF A GENERAL BELOW NORMAL TEMP REGIME
FOR UPPER MI OVER THE NEXT 7-10DAYS. WHILE SOME DAYS WILL SEE TEMPS
AROUND NORMAL...THE OVERALL PATTERN SUGGESTS THE POTENTIAL FOR SOME
CHILLY DAYS FOR EARLY AUG STANDARDS AS WELL. THIS IS ESPECIALLY TRUE
LATE WEEK WHEN THE MID LEVEL LOW PASSES AND BRINGS ITS ASSOCIATED
COLD AIR INTO THE AREA. AS FOR PCPN...THERE WILL BE INCREASING PCPN
CHANCES MON/TUE AND PROBABLY INTO WED MORNING AS SHORTWAVES EJECT
FROM A PACIFIC NW/SW CANADA TROF AND TRACK E ACROSS THE NRN CONUS
UNDERNEATH THE MID LEVEL LOW. UNSETTLED WEATHER MAY PUSH THRU THE
AREA AGAIN LATE WEEK DEPENDING ON TRACK OF THE MID LEVEL LOW ACROSS
THE UPPER LAKES AND/OR NRN ONTARIO AND DEPENDING ON WHETHER ANY
ADDITIONAL SHORTWAVES ROTATE AROUND THE LOW.
BEGINNING MON...ATTENTION WILL BE ON THE WELL-DEFINED SHORTWAVE
CURRENTLY OVER SRN SASKATCHEWAN. GIVEN THE PRONOUNCED NW FLOW THIS
MORNING OVER THE UPPER LAKES...IT WOULD SEEM THIS WAVE WON`T BE ABLE
TO MAKE A STRONG PUSH E TO UPPER MI. MODELS DO SHOW FLOW BACKING
WITH UPPER MI UNDER WNW FLOW MON...WHICH STILL SHOULD DIRECT THE
SHORTWAVE AND BULK OF FORCING ESE THRU WI AS DEPICTED BY DEEP LAYER
QVECTORS. THE AXIS OF INSTABILITY REMAINS WELL TO THE SW WITH EVEN
THE INSTABILITY GRADIENT TO THE SW OF HERE. THIS ALSO SUPPORTS THE
IDEA OF MAIN AREA OF PCPN PASSING BY TO THE S. THAT SAID...GIVEN THE
WELL-DEFINED LOOK OF THE SHORTWAVE...SOME PCPN WILL PROBABLY STILL
BRUSH UPPER MI MON AS INDICATED BY ALL MODEL GUIDANCE. IN THE END...
PREFER THE MORE LIMITED NORTHWARD PUSH OF PCPN SHOWN BY THE ECMWF
AND THE 4KM HIGH RES NAM NEST GIVEN ABOVE DISCUSSION. WITH
INSTABILITY AND INSTABILITY GRADIENT TO THE SW...THUNDER LOOKS
UNLIKELY AND WON`T BE MENTIONED. IF THERE IS ANY THUNDER...IT
SHOULD ONLY AFFECT AREAS TOWARD THE WI BORDER.
FCST FOR MON NIGHT IS FAIRLY UNCERTAIN. IT WOULD SEEM DRY WEATHER
SHOULD FOLLOW AS SHORTWAVE CONTINUES TO THE ESE. 850MB WAA AND 850MB
WINDS ARE WEAK (10-15KT)...CERTAINLY SUGGESTING MINIMAL POTENTIAL
FOR MORE ORGANIZED PCPN AREAS. HOWEVER...WITH CYCLONIC 850MB FLOW
AND HINTS OF ONE OR TWO SUBTLE TROFS IN THE WIND FIELD...WILL
MAINTAIN SCHC POPS FOR MUCH OF THE AREA THRU THE NIGHT.
ON TUE...UNUSUALLY DEEP MID LEVEL LOW FOR EARLY AUG WILL BE WOBBLING
S ROUGHLY ALONG THE NE MANITOBA/NRN ONTARIO BORDER. AS A RESULT...
FLOW WILL CONTINUE TO BACK ACROSS THE UPPER GREAT LAKES UNDER THE
EXPANDING CIRCULATION AROUND THE LOW. TO THE W...COMBINATION OF A
SHORTWAVE ROTATING AROUND THE MID LEVEL LOW AND A SHORTWAVE PICKED
UP FROM THE PACIFIC NW/SW CANADA WILL LEAD TO AN ORGANIZING COLD
FRONT MOVING ACROSS THE NRN PLAINS TUE. ORGANIZED PCPN ASSOCIATED
WITH FRONT SHOULD REMAIN W OF UPPER MI THRU TUE AFTN. ACROSS UPPER
MI...NAM/GFS SHOW MLCAPE INCREASING TO AROUND 500J/KG TUE. WITH
HINTS OF A SUBTLE SHORTWAVE PASSING ACROSS THE AREA...WILL INCLUDE
LOW CHC POPS FOR SHRA/TSRA.
AS WAS THE CASE YESTERDAY...MODELS STILL SUGGEST TUE NIGHT AS HAVING
THE BEST SHOT OF SHRA/TSRA AS COLD FRONT PASSES ACROSS UPPER MI TUE
NIGHT/WED MORNING. THERE ARE STILL SOME TIMING ISSUES TO SORT OUT AS
THE GFS/NAM HAVE FRONT OVER THE FAR ERN FCST AREA AT 12Z WED WHILE
THE ECMWF/GEM ARE ABOUT 6-9HRS SLOWER. THE TIMING UNCERTAINTY LEADS
TO LOWER CONFIDENCE IN PIN POINTING PERIOD OF HIGHER POPS. TAKING
INTO ACCOUNT GFS/ECMWF GUIDANCE OVER THE LAST DAY OR TWO...WILL
HEDGE FCST SLIGHTLY TOWARD THE SLOWER SOLUTION...WHICH RESULTS IN
HANGING ONTO HIGHER POPS OVER THE E INTO WED MORNING. IN THE WAKE OF
SHORTWAVE/COLD FRONT...DRY WEATHER WILL FOLLOW W TO E DURING THE DAY
WED.
PLENTY OF UNCERTAINTY REMAINS FOR THU/FRI/SAT REGARDING TIMING/TRACK
OF THE UNUSUALLY DEEP MID LEVEL LOW (500MB HEIGHTS MAY BE AROUND 2.5
STANDARD DEVIATIONS BELOW LONG TERM AVG). IF ANYTHING...THE LAST DAY
OR TWO OF GFS/ECMWF MODEL RUNS SUGGEST A TREND FOR A SLIGHTLY SLOWER
PROGRESSION OF THE MID LEVEL LOW ACROSS NRN ONTARIO DURING THE LAST
HALF OF THE WEEK. THIS SLOWER TREND RAISES THE PROSPECT FOR AT LEAST
ONE SHORTWAVE ROTATING AROUND THE LOW TO AFFECT UPPER MI. THE
PREDICTABILITY OF TIMING A WAVE ROTATING AROUND A MID LEVEL LOW 4 TO
6 DAYS OUT IN A MODEL RUN IS VERY LOW. FOR WHAT IT`S WORTH...LATEST
GUIDANCE SUGGESTS A SHORTWAVE MAY ROTATE THRU THE UPPER LAKES FRI...
PROVIDING THE POTENTIAL FOR SOME SHRA. TEMPS WILL TURN COOLER LATE
WEEK. IN FACT...THERE COULD BE AT LEAST 1 DAY OF WELL BELOW NORMAL
TEMPS WITH HIGHS POTENTIALLY ONLY IN THE MID 50S NEAR LAKE SUPERIOR
AND LOW/MID 60S INLAND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 258 AM EDT SUN AUG 4 2013
VFR CONDITIONS TO PREVAIL THROUGH THE FORECAST. PATCHY GROUND FOG
DEVELOPED AND THEN DISSIPATED AT KIWD EARLIER THIS
EVENING...TEMPORARILY PRODUCING IFR VISIBILITIES...AND MAY REFORM
LATER OVERNIGHT AS TEMPS/DEWPOINTS CONVERGE. WILL INCLUDE IN FOG IN
KIWD FORECAST AS A TEMPO GROUP AS CONFIDENCE IS NOT HIGH FOR ANY FOG
TO PERSIST. HIGH PRESSURE CONTINUES TO BUILD INTO THE REGION
OVERNIGHT PRODUCING MOSTLY CLEAR SKIES AND LIGHT WINDS. AFTER
DAYBREAK...WINDS WILL PICK UP AGAIN SLIGHTLY BUT SPEEDS WILL REMAIN
BELOW 10 KTS. KSAW WILL ONCE AGAIN BE AFFECTED BY A LAKE BREEZE
DURING THE LATE MORNING HOURS. CLOUD COVER WILL BE ON THE INCREASE
LATE IN THE FORECAST AT KIWD WITH APPROACH OF THE NEXT SYSTEM BUT
ANY PRECIPITATION WILL HOLD OFF BEYOND THIS FORECAST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 454 AM EDT SUN AUG 4 2013
THROUGH THIS FCST PERIOD...WINDS SHOULD BE NO HIGHER THAN 20KT WITH
GENERALLY A WEAK PRESSURE GRADIENT DOMINATING THE UPPER GREAT LAKES.
HOWEVER...WILL NEED TO CONTINUE WATCHING THE MID WEEK PERIOD AS A
PASSING COLD FRONT COULD LEAD TO STRONGER PRE FRONTAL AND ESPECIALLY
POST FRONTAL WINDS IN THE LATE TUE/WED TIME FRAME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...RJT
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
537 AM CDT SUN AUG 4 2013
.UPDATE...
AVIATION ADDED BELOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT SUN AUG 4 2013
SFC HIGH PRESSURE OVERHEAD TO START TODAY HAS US STARTING OUT WITH
ANOTHER SEASONABLY COOL EARLY AUGUST MORNING. A QUICK LOOK AT WATER
VAPOR SHOWS THE CULPRIT FOR WHAT EVENTUALLY WILL BECOME CATEGORICAL
POPS TONIGHT AND THAT IS A PRETTY POTENT SHORT WAVE SPINNING ACROSS
FAR SW ALBERTA. THIS WAVE GENERATED SOME FAIRLY ROBUST CONVECTION
ACROSS MONTANA LAST NIGHT...WHICH IS NOW ACROSS THE WRN DAKOTAS. A
CONVECTIVELY INDUCED SHORT WAVE IS ASSOCIATED WITH THE DAKOTAS
ACTIVITY. THE DAKOTAS SHORTWAVE IS PROGGED BY THE RAP TO MOVE INTO
NRN MN BY THIS AFTERNOON. HOWEVER...IT WILL NOT BE BRINGING THE
ELEVATED INSTABILITY AND MOISTURE TRANSPORT WITH IT...SO THIS WAVE
WILL DO NOTHING MORE THAN GIVE US A CLOUDIER DAY THAN WHAT WAS SEEN
YESTERDAY. THE ALBERTA WAVE WILL FOLLOW ON THE HEELS OF THE DAKOTAS
WAVE FOR TONIGHT AND WILL BE THE IMPETUS FOR WHAT WILL LIKELY BE AN
ELEVATED MCS ACROSS MUCH OF THE ERN HALF MPX AREA TONIGHT.
FOR TODAY...AS THE SFC HIGH WORKS INTO THE GREAT LAKES...WE WILL
START GETTING INTO WEAK WAA...WITH 925-850 TEMPS LOOKING TO BE A FEW
DEGREES WARMER THAN YESTERDAY...ESPECIALLY ACROSS MN. HOWEVER...MORE
CLOUD COVER IS EXPECTED TODAY THAN YESTERDAY...WHICH SHOULD OFFSET
THIS SLIGHT WARMING...WITH HIGHS TODAY VERY SIMILAR TO SATURDAY AS A
RESULT. STILL HAVE SOME CHANCE POPS REMAINING OUT IN WRN MN THIS
AFTERNOON AS H85 MOISTURE TRANSPORT AND ELEVATED INSTABILITY
BEGIN WORKING INTO MN. BEST SIGNAL FOR PRECIP FOR TODAY LOOKS TO BE
ACROSS NRN MN...WHERE THE GFS/NAM ARE SHOWING SOME DECENT FGEN
DEVELOPING IN THE H85-H5 LAYER...WHICH IS ALSO AT THE NOSE OF THE
H85 MOISTURE TRANSPORT. THIS SHOULD GENERATE AN AREA OF SHOWERS
ACROSS NW MN THAT MAY BLEED INTO WEST CENTRAL MN AFTER 18Z...BUT
STILL SEEING BETTER SIGNAL DOWN HERE FOR PRECIP TONIGHT.
AS FOR TONIGHT...THOUGH SHEERING OUT SOME...THE ALBERTA WAVE WILL BE
MOVING ACROSS NRN MN TONIGHT AND WILL STILL BE STRONG ENOUGH TO
INDUCE A NOCTURNAL STRENGTHENING OF THE LLJ ACROSS MN. NAM/ECMWF/GFS
ALL FAIRLY SIMILAR WITH THE NOSE OF AN ENHANCED AREA OF 925-850
MOISTURE TRANSPORT COMING UP TO ABOUT I-94 FROM 6Z AND BEYOND. AS A
RESULT...HELD OFF ON ANY LIKELY OR HIGHER POPS UNTIL AFTER 6Z...WITH
HEAVIEST AXIS OF PRECIP TONIGHT EXPECTED FROM STC DOWN TOWARD
RST/LSE AND OVER TOWARD EAU. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...BUT PLENTY OF ELEVATED INSTABILITY WILL BE PRESENT TO
ENSURE THESE SHOWERS COME IN THE FORM OF THUNDERSTORMS. AS FOR
PRECIP AMOUNTS...THIS FEATURE LOOKS TO BE TRANSIENT ENOUGH TO KEEP
ACTIVITY MOVING ALONG...BUT WITH PWATS INCREASING TO NEAR 1.5
INCHES...COULD CERTAINLY SEEN AN AXIS OR TWO OF 1 TO 2 INCH RAINFALL
AMOUNTS IF SOME CELL TRAINING OCCURS...THOUGH FOR THE MOST PART
RAINFALL AMOUNTS WILL LIKELY BE A HALF TO ONE INCH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 317 AM CDT SUN AUG 4 2013
SOME RESIDUAL PCPN FROM TONIGHT/S ACTIVITY SHOULD STILL BE
LINGERING OVER THE EASTERN PORTION OF THE AREA MONDAY MORNING.
HOWEVER... THE 850MB FRONTOGENESIS AND MOISTURE TRANSPORT QUICKLY
SHIFTS EAST OF THE AREA ON MONDAY ALONG WITH THE 305-310K
ISENTROPIC LIFT. SO... EXPECT THE MORE WIDESPREAD PCPN TO SHIFT TO
OUR EAST MONDAY MORNING... LEAVING MAINLY DRY CONDITIONS FOR THE
REMAINDER OF THE DAY. HOWEVER... NEGATIVE 850-500MB DIFFERENTIAL
THETA-E VALUES REMAIN IN PLACE THROUGH THE DAY... INDICATING THE
RESIDUAL CONVECTIVE INSTABILITY THAT WILL BE OVER THE AREA. WITH
NO LARGE SCALE FORCING... DON/T EXPECT MUCH PCPN AFTER MONDAY
MORNING... BUT THE LINGERING INSTABILITY COULD LEAD TO A FEW
SHRA/TSRA MONDAY AFTERNOON INTO MONDAY EVENING... PARTICULARLY
OVER THE NORTHERN AND EASTERN PORTION OF THE AREA WHERE BETTER
LAPSE RATES ARE SUGGESTED. THE ARW AND NMM HIGH RESOLUTION WINDOW
RUNS BOTH MANAGE TO DEVELOP SOME SCATTERED SHRA/TSRA MONDAY
AFTERNOON GIVEN THIS SCENARIO... SO KEPT SOME LOW CHANCE POPS
GOING TO ACCOUNT FOR THE POSSIBILITY.
CHANCES FOR MORE WIDESPREAD PCPN WILL RETURN FROM WEST TO EAST ON
TUESDAY AS THE MAIN FRONTAL BOUNDARY WORKS INTO THE AREA WHILE A
STRONG 500MB TROUGH DROPS SOUTH FROM CENTRAL CANADA TOWARD THE
UPPER GREAT LAKES. THERE APPEARS TO BE LESS IN THE WAY OF POTENTIAL
FOR SEVERE WEATHER IN COMPARISON TO EARLIER GUIDANCE... WITH THE
BETTER INSTABILITY STAYING SOUTH OF THE AREA... AND THE FRONTAL
BOUNDARY LOOKING TO BE MORE DIFFUSE AND LATER IN ITS ARRIVAL.
HOWEVER... DEEP LAYER SHEAR IS STILL PROGGED BY THE NAM AND GFS TO
BE AOA 40 KT TUESDAY AFTERNOON INTO TUESDAY EVENING... WITH SOME
MLCAPE VALUES AOA 1000 J/KG CERTAINLY STILL POSSIBLE. LOW LEVEL
SHEAR IS MINIMAL WITH LOW LEVEL WINDS LOOKING TO BECOME
SOUTHWESTERLY AHEAD OF THE FRONT GIVEN ITS ORIENTATION AND LACK OF
ANY DECENT PRESSURE FALLS. WITH THE BEST DYNAMIC FORCING TO OUR
NORTH AND THE BEST THERMODYNAMIC FORCING TO OUR SOUTH... DON/T
EXPECT TO SEE ANYTHING TOO SIGNIFICANT ACROSS OUR AREA AT THIS
POINT. THERE APPEARS TO BE SUFFICIENT INSTABILITY... LOW LEVEL
CONVERGENCE... AND DIFFERENTIAL DIVERGENCE TO GET SOME SHRA/TSRA
GOING... AND GIVEN THE DECENT DEEP LAYER SHEAR IT/S POSSIBLE FOR A
FEW NEAR-SEVERE STORMS... BUT ANYTHING OF SIGNIFICANCE LOOKS TO BE
TO OUR SOUTH AT THIS POINT.
HIGH PRESSURE WILL BUILD ACROSS THE AREA TUESDAY NIGHT INTO
WEDNESDAY... WITH DRY AND COOLER CONDITIONS EXPECTED TO PERSIST
INTO THURSDAY. ANOTHER COLD FRONT WILL MOVE ACROSS THE AREA
SOMETIME FROM LATE THURSDAY INTO FRIDAY... BRINGING A CHANCE FOR
SHRA/TSRA... ALTHOUGH THERE DOESN/T LOOK TO BE MUCH OPPORTUNITY
FOR MOISTURE TRANSPORT AHEAD OF IT. THE TIMING OF THIS NEXT FRONT
IS A GOOD 18 HOURS DIFFERENT BETWEEN THE GFS AND ECMWF... WITH THE
GFS BEING QUICKER. PLAYED THE TIMING IN THE MIDDLE OF THE TWO
SOLUTIONS AT THIS POINT RATHER THAN BLANKETING AN OVERLY LONG
PERIOD WITH CHANCE POPS. ONCE THIS FRONT PUSHES THROUGH WE/LL SEE
HIGH PRESSURE BUILD IN ACROSS THE AREA FOR SATURDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 520 AM CDT SUN AUG 4 2013
HIGH PRESSURE WILL SLIDE FROM MN THIS MORNING INTO THE GREAT
LAKES TONIGHT. RETURN FLOW WILL BECOME ESTABLISHED ACROSS MN
TODAY...AND BY TONIGHT...CONFIDENCE IS INCREASING IN A COMPLEX OF
TSRA DEVELOPING...ESPECIALLY AFTER 6Z EAST OF AXN/RWF. STILL
DISSAGREEMENT ON PLACEMENT OF THIS ACTIVITY...WITH NAM MAINLY
NORTH OF I-94...ECMWF SOUTH OF I-94 AND THE GFS ALONG I-94. STUCK
WITH THE MIDDLE ROAD FOR THESE TAFS. ONCE FOG BURNS OFF IN EAU
THIS MORNING...EXPECT ANOTHER PERIOD OF VFR CONDITIONS OUTSIDE OF
ANY PRECIP. MAIN CHANGE IN WEATHER COMPARED TO SATURDAY IS THERE
WILL BE MORE MID/UPPER LEVEL CLOUD COVER DURING THE DAY...AND
WINDS WILL BE TURNING OVER TO THE SOUTH.
KMSP...CONDITIONS LOOK GOOD UNTIL TONIGHT...WHEN THUNDERSTORMS ARE
EXPECTED TO DEVELOP ON THE NOSE OF A LLJ. COULD SEE ACIVITIY MOVE
IN PRIOR TO 6Z...BUT LLJ SUPPORT DOES NOT LOOK TO BECOME FAVORABLE
UNTIL AFTER 6Z...WITH THE 8-12Z WINDOW CURRENTLY LOOKING THE MOST
LIKELY ONE FOR SEEING THUNDER. FUTURE SHIFTS SHOULD BE ABLE TO
NARROW DOWN THE PRECIP WINDOW FROM 6 TO 2 OR 3 HOURS AS CONFIDENCE
IN TIMING INCREASES.
/OUTLOOK FOR KMSP/
MON...VFR. ISOL TSRA POSSIBLE IN AFTERNOON. WINDS BMNG NW AT LESS
THAN 10 KTS.
TUE...MVFR CONDS POSSIBLE WITH A CHANCE OF SHRA/TSRA. WINDS SW
5-10 KTS...SHIFTING TO NW OVERNIGHT.
WED...VFR. WINDS NNW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
333 AM CDT SUN AUG 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT SUN AUG 4 2013
SFC HIGH PRESSURE OVERHEAD TO START TODAY HAS US STARTING OUT WITH
ANOTHER SEASONABLY COOL EARLY AUGUST MORNING. A QUICK LOOK AT WATER
VAPOR SHOWS THE CULPRIT FOR WHAT EVENTUALLY WILL BECOME CATEGORICAL
POPS TONIGHT AND THAT IS A PRETTY POTENT SHORT WAVE SPINNING ACROSS
FAR SW ALBERTA. THIS WAVE GENERATED SOME FAIRLY ROBUST CONVECTION
ACROSS MONTANA LAST NIGHT...WHICH IS NOW ACROSS THE WRN DAKOTAS. A
CONVECTIVELY INDUCED SHORT WAVE IS ASSOCIATED WITH THE DAKOTAS
ACTIVITY. THE DAKOTAS SHORTWAVE IS PROGGED BY THE RAP TO MOVE INTO
NRN MN BY THIS AFTERNOON. HOWEVER...IT WILL NOT BE BRINGING THE
ELEVATED INSTABILITY AND MOISTURE TRANSPORT WITH IT...SO THIS WAVE
WILL DO NOTHING MORE THAN GIVE US A CLOUDIER DAY THAN WHAT WAS SEEN
YESTERDAY. THE ALBERTA WAVE WILL FOLLOW ON THE HEELS OF THE DAKOTAS
WAVE FOR TONIGHT AND WILL BE THE IMPETUS FOR WHAT WILL LIKELY BE AN
ELEVATED MCS ACROSS MUCH OF THE ERN HALF MPX AREA TONIGHT.
FOR TODAY...AS THE SFC HIGH WORKS INTO THE GREAT LAKES...WE WILL
START GETTING INTO WEAK WAA...WITH 925-850 TEMPS LOOKING TO BE A FEW
DEGREES WARMER THAN YESTERDAY...ESPECIALLY ACROSS MN. HOWEVER...MORE
CLOUD COVER IS EXPECTED TODAY THAN YESTERDAY...WHICH SHOULD OFFSET
THIS SLIGHT WARMING...WITH HIGHS TODAY VERY SIMILAR TO SATURDAY AS A
RESULT. STILL HAVE SOME CHANCE POPS REMAINING OUT IN WRN MN THIS
AFTERNOON AS H85 MOISTURE TRANSPORT AND ELEVATED INSTABILITY
BEGIN WORKING INTO MN. BEST SIGNAL FOR PRECIP FOR TODAY LOOKS TO BE
ACROSS NRN MN...WHERE THE GFS/NAM ARE SHOWING SOME DECENT FGEN
DEVELOPING IN THE H85-H5 LAYER...WHICH IS ALSO AT THE NOSE OF THE
H85 MOISTURE TRANSPORT. THIS SHOULD GENERATE AN AREA OF SHOWERS
ACROSS NW MN THAT MAY BLEED INTO WEST CENTRAL MN AFTER 18Z...BUT
STILL SEEING BETTER SIGNAL DOWN HERE FOR PRECIP TONIGHT.
AS FOR TONIGHT...THOUGH SHEERING OUT SOME...THE ALBERTA WAVE WILL BE
MOVING ACROSS NRN MN TONIGHT AND WILL STILL BE STRONG ENOUGH TO
INDUCE A NOCTURNAL STRENGTHENING OF THE LLJ ACROSS MN. NAM/ECMWF/GFS
ALL FAIRLY SIMILAR WITH THE NOSE OF AN ENHANCED AREA OF 925-850
MOISTURE TRANSPORT COMING UP TO ABOUT I-94 FROM 6Z AND BEYOND. AS A
RESULT...HELD OFF ON ANY LIKELY OR HIGHER POPS UNTIL AFTER 6Z...WITH
HEAVIEST AXIS OF PRECIP TONIGHT EXPECTED FROM STC DOWN TOWARD
RST/LSE AND OVER TOWARD EAU. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...BUT PLENTY OF ELEVATED INSTABILITY WILL BE PRESENT TO
ENSURE THESE SHOWERS COME IN THE FORM OF THUNDERSTORMS. AS FOR
PRECIP AMOUNTS...THIS FEATURE LOOKS TO BE TRANSIENT ENOUGH TO KEEP
ACTIVITY MOVING ALONG...BUT WITH PWATS INCREASING TO NEAR 1.5
INCHES...COULD CERTAINLY SEEN AN AXIS OR TWO OF 1 TO 2 INCH RAINFALL
AMOUNTS IF SOME CELL TRAINING OCCURS...THOUGH FOR THE MOST PART
RAINFALL AMOUNTS WILL LIKELY BE A HALF TO ONE INCH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 317 AM CDT SUN AUG 4 2013
SOME RESIDUAL PCPN FROM TONIGHT/S ACTIVITY SHOULD STILL BE
LINGERING OVER THE EASTERN PORTION OF THE AREA MONDAY MORNING.
HOWEVER... THE 850MB FRONTOGENESIS AND MOISTURE TRANSPORT QUICKLY
SHIFTS EAST OF THE AREA ON MONDAY ALONG WITH THE 305-310K
ISENTROPIC LIFT. SO... EXPECT THE MORE WIDESPREAD PCPN TO SHIFT TO
OUR EAST MONDAY MORNING... LEAVING MAINLY DRY CONDITIONS FOR THE
REMAINDER OF THE DAY. HOWEVER... NEGATIVE 850-500MB DIFFERENTIAL
THETA-E VALUES REMAIN IN PLACE THROUGH THE DAY... INDICATING THE
RESIDUAL CONVECTIVE INSTABILITY THAT WILL BE OVER THE AREA. WITH
NO LARGE SCALE FORCING... DON/T EXPECT MUCH PCPN AFTER MONDAY
MORNING... BUT THE LINGERING INSTABILITY COULD LEAD TO A FEW
SHRA/TSRA MONDAY AFTERNOON INTO MONDAY EVENING... PARTICULARLY
OVER THE NORTHERN AND EASTERN PORTION OF THE AREA WHERE BETTER
LAPSE RATES ARE SUGGESTED. THE ARW AND NMM HIGH RESOLUTION WINDOW
RUNS BOTH MANAGE TO DEVELOP SOME SCATTERED SHRA/TSRA MONDAY
AFTERNOON GIVEN THIS SCENARIO... SO KEPT SOME LOW CHANCE POPS
GOING TO ACCOUNT FOR THE POSSIBILITY.
CHANCES FOR MORE WIDESPREAD PCPN WILL RETURN FROM WEST TO EAST ON
TUESDAY AS THE MAIN FRONTAL BOUNDARY WORKS INTO THE AREA WHILE A
STRONG 500MB TROUGH DROPS SOUTH FROM CENTRAL CANADA TOWARD THE
UPPER GREAT LAKES. THERE APPEARS TO BE LESS IN THE WAY OF POTENTIAL
FOR SEVERE WEATHER IN COMPARISON TO EARLIER GUIDANCE... WITH THE
BETTER INSTABILITY STAYING SOUTH OF THE AREA... AND THE FRONTAL
BOUNDARY LOOKING TO BE MORE DIFFUSE AND LATER IN ITS ARRIVAL.
HOWEVER... DEEP LAYER SHEAR IS STILL PROGGED BY THE NAM AND GFS TO
BE AOA 40 KT TUESDAY AFTERNOON INTO TUESDAY EVENING... WITH SOME
MLCAPE VALUES AOA 1000 J/KG CERTAINLY STILL POSSIBLE. LOW LEVEL
SHEAR IS MINIMAL WITH LOW LEVEL WINDS LOOKING TO BECOME
SOUTHWESTERLY AHEAD OF THE FRONT GIVEN ITS ORIENTATION AND LACK OF
ANY DECENT PRESSURE FALLS. WITH THE BEST DYNAMIC FORCING TO OUR
NORTH AND THE BEST THERMODYNAMIC FORCING TO OUR SOUTH... DON/T
EXPECT TO SEE ANYTHING TOO SIGNIFICANT ACROSS OUR AREA AT THIS
POINT. THERE APPEARS TO BE SUFFICIENT INSTABILITY... LOW LEVEL
CONVERGENCE... AND DIFFERENTIAL DIVERGENCE TO GET SOME SHRA/TSRA
GOING... AND GIVEN THE DECENT DEEP LAYER SHEAR IT/S POSSIBLE FOR A
FEW NEAR-SEVERE STORMS... BUT ANYTHING OF SIGNIFICANCE LOOKS TO BE
TO OUR SOUTH AT THIS POINT.
HIGH PRESSURE WILL BUILD ACROSS THE AREA TUESDAY NIGHT INTO
WEDNESDAY... WITH DRY AND COOLER CONDITIONS EXPECTED TO PERSIST
INTO THURSDAY. ANOTHER COLD FRONT WILL MOVE ACROSS THE AREA
SOMETIME FROM LATE THURSDAY INTO FRIDAY... BRINGING A CHANCE FOR
SHRA/TSRA... ALTHOUGH THERE DOESN/T LOOK TO BE MUCH OPPORTUNITY
FOR MOISTURE TRANSPORT AHEAD OF IT. THE TIMING OF THIS NEXT FRONT
IS A GOOD 18 HOURS DIFFERENT BETWEEN THE GFS AND ECMWF... WITH THE
GFS BEING QUICKER. PLAYED THE TIMING IN THE MIDDLE OF THE TWO
SOLUTIONS AT THIS POINT RATHER THAN BLANKETING AN OVERLY LONG
PERIOD WITH CHANCE POPS. ONCE THIS FRONT PUSHES THROUGH WE/LL SEE
HIGH PRESSURE BUILD IN ACROSS THE AREA FOR SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 951 PM CDT SAT AUG 3 2013
VFR TAF...WITH MORE INTERESTING WEATHER BY THE END OF THE PERIOD.
BROUGHT SHOWERS INTO KAXN/KRWF/KSTC BY THE END OF THE TAF. THINK THERE
WILL BE GOOD COVERAGE OF SHOWERS WITH ISOLATED TO SCATTERED WEAK
THUNDERSTORMS DEVELOPING IN MN BETWEEN 02-06 Z TOMORROW NIGHT.
SLIGHTLY HIGHER CONFIDENCE IN OUR RAIN CHANCES FOR SUNDAY NIGHT
AND MONDAY MORNING. EAU CLAIRE COULD ONCE AGAIN SEE AN HOUR OF FOG
NEAR SUNRISE.
KMSP...
THREW IN A PROB30 FOR WEAK THUNDERSTORMS NEAR THE END OF THE TAF.
COVERAGE SHOULD BE SCATTERED...SO NOT HIGH CONFIDENCE IN THE
AIRPORT GETTING HIT AT THIS TIME. BETTER FOCUS MIGHT BE JUST A
COUNTY OR TWO SOUTH OF THE AIRPORT - SHOULD BE CLOSE THOUGH.
/OUTLOOK FOR KMSP/
MON...MVFR CONDS POSSIBLE IN THE MORNING WITH A CHANCE OF
SHRA/TSRA. WINDS S TO W LESS THAN 10 KT.
TUE...MVFR CONDS POSSIBLE WITH A CHANCE OF SHRA/TSRA. WINDS SW 5-10
KTS...SHIFTING TO NW OVERNIGHT.
WED...VFR. WINDS NNW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...
AVIATION...CLF
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
844 PM CDT MON AUG 5 2013
.UPDATE...
ISSUED AT 844 PM CDT MON AUG 5 2013
THUNDERSTORMS HAVE STAYED SOUTHWEST OF THE CWA THIS EVENING...
THOUGH DO EXPECT ADDITIONAL STORMS TO DEVELOP FROM EASTERN KANSAS
INTO SOUTHEAST MISSOURI OVERNIGHT. THESE STORMS WILL DEVELOP IN A
BAND OF LOW LEVEL MOISTURE CONVERGENCE ON THE BROAD NOSE OF A LOW
LEVEL JET. LATEST RUNS OF THE HRRR SUGGESTS THAT NORTHERN AND
EASTERN EDGE OF THUNDERSTORMS WILL MOVE INTO CENTRAL AND SOUTHEAST
MISSOURI TOWARD SUNRISE...WITH BEST COVERAGE ACROSS SOUTHEAST
MISSOURI INTO SOUTHERN ILLINOIS BETWEEN 10-15Z. HAVE ADJUSTED RAIN
CHANCES TO GO ALONG WITH THIS IDEA. OTHERWISE...GOING FORECAST
LOOKS GOOD AND ONLY MADE MINOR TWEAKS TO TEMPERATURE AND CLOUD
COVER TO MATCH WITH GOING TRENDS.
BRITT
&&
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 333 PM CDT MON AUG 5 2013
FRONTAL BOUNDARY TO THE SOUTH WILL SLOWLY RETREAT AND MOVE NORTHWARD
OVERNIGHT TONIGHT. ISOLATED TO SCATERRED CONVECTION HAS DEVELOPED
ALONG IT OVER THE PAST COUPLE OF HOURS ACROSS PORTIONS OF SW
MISSOURI. THINKING THAT THIS CONVECTION SHOULD WEAKEN AND DIE OUT
THIS EVENING WITH LOSS OF DAYLIGHT HEATING. TIED HIGHEST POPS
TONIGHT TO PORTIONS OF SOUTH CENTRAL AND SOUTHEAST MISSOURI WHICH
WILL BE IN CLOSER PROXIMITY TO AFOREMENTIONED FRONT. DID LOWER
POPS A BIT FROM PREVIOUS FORECAST AS CONVERGENCE ALONG FRONT IS
RATHER WEAK AND LOW LEVEL FORCING IS PROGGED TO BE NOT NEARLY AS
STRONG OR FOCUSED TONIGHT AS PREVIOUS FEW NIGHTS. ALONG AND NORTH
OF BOUNDARY LOW STRATUS...AND POSSIBLY FOG...TO AFFECT MUCH OF THE
REGION WHICH WILL HELP KEEP LOW TEMPERATURES UP IN THE UPPER 60S
TO LOW 70S. BOOSTED LOWS A DEGREE OR TWO ABOVE WARMER MAV
GUIDANCE DUE TO EXPECTED LOW CLOUD COVER OVERNIGHT TONIGHT.
GOSSELIN
.LONG TERM...(TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 333 PM CDT MON AUG 5 2013
WITH WAA/ISENTROPIC ASCENT STILL OVER OUR AREA TUESDAY MORNING
COUPLED WITH A FEW VORTICITY MAXIMA RIDING OVER A RIDGE TO OUR SW...
THE SHOWERS AND THUNDERSTORMS THAT DEVELOPS OVERNIGHT SHOULD
CONTINUE TO PROPAGATE INTO OUR S COUNTIES DURING THE
MORNING...WITH LIKELY POPS AS FAR N AS A COLUMBIA TO SPARTA LINE.
ELSEWHERE...WILL MAINTAIN CHANCE OF POPS THROUGHOUT THE DAY...AS
TONGUE OF WAA PERSISTS OVER OUR AREA COUPLED WITH A FEW WEAK
SHORTWAVES WITHIN THE GENERAL FLOW. BY TUESDAY NIGHT...EXPECTING
AN UPTICK IN CONVECTIVE ACTIVITY OVER THE N 2/3 OF THE CWA AS WAA
INTENSIFIES EVEN MORE AHEAD OF APPRROACHING SHORTWAVE AND
ASSOCIATED COLD FRONT.
ON WEDNESDAY THE COLD FRONT IS EXPECTED TO SWEEP ACROSS THE AREA.
SOME MODELS SUGGEST THAT THE IMPACTS OF THE OVERNIGHT CONVECTION MAY
INHIBIT ADDITIONAL DEVELOPMENT OF CONVECTION ALONG THE FRONT DURING
THE DAY. HOWEVER...HAVE NOT MADE ANY MAJOR CHANGES TO CURRENT POPS ATTM.
12Z GFS REBOUNDS THE FRONTAL BOUNDARY AS A WARM FRONT ACROSS
OUR AREA LATE WEDNESDAY INTO THURSDAY MORNING IN RESPONSE TO A
DEEPENING SHORTWAVE TO THE WEST...WHILE MANY OF THE OTHER 12Z
SOLUTIONS ALLOW THE FRONTAL BOUNDARY TO SETTLE INTO N ARKANSAS.
WHILE THIS WILL IMPACT TEMPS...ALL SOLUTIONS POINT TO ACTIVE
BAROCLINIC ZONE REMAINING OVER S MISSOURI AND S ILLINOIS. THEREFORE
HAVE MAINTAINED LIKELY POPS OVER SOUTHERN SECTIONS OF THE CWA
THROUGH THURSDAY NIGHT WITH A CHANCE OF POPS ACROSS THE NORTH.
WITH TIME...MEDIUM RANGE SOLUTIONS DO INIDICATE THAT THE
BAROCLINIC ZONE WILL SAG SOUTH...WHICH IN TURN SHOULD ALLOW A SLOW
DECREASE IN POPS IN THE FRIDAY-SATURDAY TIME FRAME. HOWEVER...IT
APPEARS THAT TSRA THREAT WILL BE RETURNING BY THE START OF NEXT
WEEK AS LOW LEVEL WARM ADVECTION REDEVELOPS ACROSS THE REGION.
HUSTEDDE/TRUETT
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1241 PM CDT MON AUG 5 2013
RIDGE OF SFC HIGH PRESSURE CONTINUE TO SLIDE OFF TO THE EAST WITH
WINDS NOW OUT OF THE SOUTH NEAR 10 KTS. RAIN ASSOCIATED WITH
OVERNIGHT MCS HAS LARGELY STAYED SOUTH OF TAF SITES.
HOWEVER...SOME MVFR CEILINGS ARE POSSIBLE THROUGH MID AFTERNOON TO
THE NORTH OF THIS FEATURE. CEILINGS WILL ALSO BE THE PRIMARY
CONCERN TONIGHT. FRONT OVER THE MID SOUTH WILL RETREAT NORTHWARD
TONIGHT AS A WARM FRONT WITH WINDS BACKING MORE TO THE SOUTHEAST
AROUND 5 KNOTS. LOW CEILINGS ARE LIKELY WITH FOG POSSIBLE AHEAD OF THE
FRONT AND AM FORECASTING MVFR CEILINGS...THOUGH MODELS INDICATE
THEY COULD DIP DOWN INTO IFR. WARM FRONT WILL PASS THROUGH THE
AREA BY AROUND NOON WITH AREAS TO THE SOUTH OF THE BOUNDARY
HAVING WINDS VEER TO THE SOUTH SOUTHWEST.
SPECIFICS FOR KSTL...
RIDGE OF SFC HIGH PRESSURE CONTINUE TO SLIDE OFF TO THE EAST WITH
WINDS NOW OUT OF THE SOUTH NEAR 10 KTS. RAIN ASSOCIATED WITH
OVERNIGHT MCS HAS LARGELY STAYED SOUTH OF LAMBERT FIELD.
HOWEVER...SOME MVFR CEILINGS ARE POSSIBLE THROUGH MID AFTERNOON TO
THE NORTH OF THIS FEATURE. LEFT OUT OF TAF FOR NOW AS 975 TO 900
HPA MEAN FLOW HAS VEERED TO THE WEST NORTHWEST AND SHOULD KEEP
THESE AFOREMENTIONED CEILINGS JUST TO THE SOUTH OF THE TERMINAL.
HOWEVER...WILL MONITOR AND AMEND AS NECESSARY THIS AFTERNOON. CEILINGS
WILL ALSO BE THE PRIMARY CONCERN TONIGHT. FRONT OVER THE MID SOUTH
WILL RETREAT NORTHWARD TONIGHT AS A WARM FRONT WITH WINDS BACKING
MORE TO THE SOUTHEAST AROUND 5 KNOTS. LOW CEILINGS ARE LIKELY WITH
FOG POSSIBLE AHEAD OF THE FRONT AND AM FORECASTING MVFR
CEILINGS...THOUGH MODELS INDICATE THEY COULD DIP DOWN INTO IFR.
WARM FRONT WILL PASS THROUGH THE AREA BY AROUND NOON WITH AREAS TO
THE SOUTH OF THE BOUNDARY HAVING WINDS VEER TO THE SOUTH
SOUTHWEST. THE ATMOSPHERE WILL ALSO BECOME INCREASINGLY UNSTABLE
SO INTRODUCED A VCSH GROUP BEGINNING AT 1900 UTC.
GOSSELIN
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
406 PM CDT Sun Aug 4 2013
.SHORT TERM...(This Evening through Monday Night)
Issued at 406 PM CDT SUN AUG 4 2013
Tonight...12Z operational models, especially the NAM, had difficulty
evaluating the mesoscale features from last nights/todays MCS with
double MVC...mesoscale vorticity center...structure. As one would
expect the short range HRRR did a much better job with this system.
The trailing MVC now moving into southeastern KS is aiding
downstream scattered areas of rain from the southern CWA southward
across southern MO. The latest HRRR maintains this area of
precipitation through mid evening and then steadily diminishes it.
Will follow this trend for the evening hours. Thunder chances look
minimal owing to less than stellar instability due to the
rain-cooled airmass and extensive cloud shield.
Looking upstream within the monsoonal flow circulating around the
Southern Plains upper high yields little if any clues for the next
shortwave or disturbance aloft which could generate new convection.
However, believe convection for the overnight hours lies with the
increasing southwesterly low level jet that is expected to form from
the Southern Plains into KS. GFS and NAM output both signal
increasing moisture convergence and isentropic ascent will likely
generate another convective complex. Due to the subsidence left
behind from todays MCS and the models poor handling of this feature
have some question as to where this convection will form. For now
will place my bet on southeastern KS with the activity spreading
into and across mainly the southern CWA. In addition to the rain
tonight am expecting to see MVFR type fog form.
Monday-Monday night...Models show no discernible disturbances
embedded with the northwest flow which will affect the CWA during
the daylight hours. So, rain chances are most likely tied to the
morning hours and across the far southern counties where the combo
of isentropic lift and a weakening low level jet aid a departing
MCS. Have backed off on high temperatures by a handful of degrees as
warm front not likely to move into the CWA and amount of residual
cloud cover will impact surface heating.
The nocturnal low-level jet is expected to reform Monday night and
enhance the lift along/north of the surface front which is expected
to lift northward across central/eastern KS and west central MO
later in the evening. Have moderate confidence this will generate
some healthy convection and will increase PoPs after midnight for
the western counties.
.LONG TERM...(Tuesday through Sunday)
Issued at 406 PM CDT SUN AUG 4 2013
Slight northwest to almost zonal type flow regime will continue
across the central US as the Hudson Bay vortex across southern
Canada will deepen as it slowly progresses towards southern Ontario
and the northern Great Lakes region. A shortwave trough will rotate
along the periphery of this system and help to push a cold front
southeastward through the Central Plains. This front will near the
area by Tuesday night and will be the focus for convective
development Tuesday night into Wednesday morning. The expected MCS
will initially develop north of the CWA, along the front, during the
afternoon and gradually make its way into the CWA as the evening
progresses.
The remainder of the week will see spotty precipitation chances as
the Hudson Bay low gradually moves eastward and ridging remains
positioned across the Rockies. A few shortwave troughs may ride the
ridge and help to initiate convection across the region.
Temperatures will be slightly cooler behind this front as surface
high slides into the region, but will gradually warm into the mid
80s as we near the weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon)
Issued at 1240 PM CDT SUN AUG 4 2013
Complicated and messy forecast. Rain continues to have a hard time
advancing east as drier air advects in from the east. Satellite and
radar trends indicate the area of rain is dissipating. Prefer
following the short range convective allowing HRRR model as it has a
better handle on the MCS generated precipitation that is moving
across eastern KS and western MO. MVFR/IFR cigs upstream are a
concern and think cigs will bounce around between these two
categories at KMCI and KMKC during the early afternoon.
Have little confidence on seeing much if any precipitation after
this afternoon as GFS/NAM having problems resolving the MCS moving
through with the NAM developing way too much precipitation this
evening, thus the dry forecast tonight. Due to the recent rain and
considerable low level moisture left behind plus the light winds
believe MVFR fog likely with IFR cigs. Some question as to how soon
cigs could drop to IFR so amendments can be expected tonight.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...MJ
LONG TERM...PMM
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1250 PM CDT Sun Aug 4 2013
.UPDATE...
Issued at 940 AM CDT SUN AUG 4 2013
Lowered temperatures across the southwest 1/3 of the CWA based upon
extensive cloud cover and rain-cooled air. Precipitation shield
associated with KS MCS running into a brick wall of drier air that
covers northern and central MO, courtesy of easterly boundary layer
flow advecting in mid/upper 50 dewpoints, so leading edge of
convection can only creep eastward over the western CWA. Satellite
imagery shows cloud tops have markedly warmed over the past few hours
with a corresponding decrease in precipitation rates. However, cloud
tops have cooled considerably over southwest MO and thus convection
to the south of the CWA has blossomed. 12Z NAM is much more bullish
on rain over the western and central CWA for later this morning and
afternoon but given the current satellite and radar trends I have my
doubts this model is able to handle the MCS feature correctly. Prefer
to side with the latest HRRR output which appears to have a better
handle on precipitation.
&&
.SHORT TERM...(Today through Monday Afternoon)
Issued at 323 AM CDT SUN AUG 4 2013
Shortwave energy crossing the Central Plains today will bring an
increasing chance for rain to much of eastern Kansas and the western
half of Missouri today. Early this morning, a widespread area of
showers and thunderstorms continued to slowly cross central Kansas
as a shortwave visible in WV approached western Kansas. Regional VAD wind
profile data indicated that 850mb winds were finally veering this
morning in response to the shortwave. This directional turn suggests
a northward shift in the 850 baroclinic zone towards the area, with
increasing isentropic lift allowing for scattered showers to develop
across southern Nebraska and NE Kansas.
Today: Low level winds will continue to slowly veer this morning as
the shortwave tracks east southeast into central Kansas. Rain
chances will gradually increase through the morning hours as
low-level flow finally turns southwest by mid-late morning.
However, given the track of the shortwave and fairly pronounced
influences of high pressure centered over the Great Lakes, some
questions remain as to how far east rain will track today. Models
suggest highest precip chances will focus themselves during the late
morning through mid-aftn hours.
Tonight: Despite a departing shortwave, an increasing low level jet
should interact with considerable low-mid level moisture in the
region to allow for redevelopment of thunderstorms over west central
Missouri. The prevailing flow should take this activity into the
Ozarks by daybreak Monday.
Monday: The majority of Monday will likely be warm, humid but dry.
Low level thermal ridge axis stretched across the CWA will promote
rather warm temperatures approaching the 90s in some areas. A weak
surface trough and perhaps remnant outflow from overnight convection
will be a focal point for potential thunderstorm development late
Monday afternoon into Monday evening.
.LONG TERM...(Monday Evening through Saturday)
Issued at 323 AM CDT SUN AUG 4 2013
Most models agree on a weak wave tracking across the area Monday
night while a weak low-level jet noses into eastern KS. This could
support another wave of convection Monday evening particularly
across areas south of I-70. Better chances for thunderstorms still
appear in store Tuesday evening and overnight as a cold front moves
through. Better chances for widespread storms will be north of
Highway 36 where the front will arrive sooner and have better
instability to work with. Instability and shear profiles are
supportive of a large convective system with damaging winds coming
out of Nebraska and Iowa, which could survive after dark as far
south as the Missouri River.
Medium range models continue to show a rather extensive surface high
building in from the north Wednesday through Friday. This should act
to keep things mostly dry once lingering storms clear out from north
to south on Wednesday. Boundary should stall over the Ozarks on
Thursday, which could support additional storms across that region
through the end of the week. Better chances for rain through this
time should stay south of the forecast area.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon)
Issued at 1240 PM CDT SUN AUG 4 2013
Complicated and messy forecast. Rain continues to have a hard time
advancing east as drier air advects in from the east. Satellite and
radar trends indicate the area of rain is dissipating. Prefer
following the short range convective allowing HRRR model as it has a
better handle on the MCS generated precipitation that is moving
across eastern KS and western MO. MVFR/IFR cigs upstream are a
concern and think cigs will bounce around between these two
categories at KMCI and KMKC during the early afternoon.
Have little confidence on seeing much if any precipitation after
this afternoon as GFS/NAM having problems resolving the MCS moving
through with the NAM developing way too much precipitation this
evening, thus the dry forecast tonight. Due to the recent rain and
considerable low level moisture left behind plus the light winds
believe MVFR fog likely with IFR cigs. Some question as to how soon
cigs could drop to IFR so amendments can be expected tonight.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...MJ
SHORT TERM...Dux
LONG TERM...Hawblitzel
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
941 AM CDT Sun Aug 4 2013
.UPDATE...
Issued at 940 AM CDT SUN AUG 4 2013
Lowered temperatures across the southwest 1/3 of the CWA based upon
extensive cloud cover and rain-cooled air. Precipitation shield
associated with KS MCS running into a brick wall of drier air that
covers northern and central MO, courtesy of easterly boundary layer
flow advecting in mid/upper 50 dewpoints, so leading edge of
convection can only creep eastward over the western CWA. Satellite
imagery shows cloud tops have markedly warmed over the past few hours
with a corresponding decrease in precipitation rates. However, cloud
tops have cooled considerably over southwest MO and thus convection
to the south of the CWA has blossomed. 12Z NAM is much more bullish
on rain over the western and central CWA for later this morning and
afternoon but given the current satellite and radar trends I have my
doubts this model is able to handle the MCS feature correctly. Prefer
to side with the latest HRRR output which appears to have a better
handle on precipitation.
&&
.SHORT TERM...(Today through Monday Afternoon)
Issued at 323 AM CDT SUN AUG 4 2013
Shortwave energy crossing the Central Plains today will bring an
increasing chance for rain to much of eastern Kansas and the western
half of Missouri today. Early this morning, a widespread area of
showers and thunderstorms continued to slowly cross central Kansas
as a shortwave visible in WV approached western Kansas. Regional VAD wind
profile data indicated that 850mb winds were finally veering this
morning in response to the shortwave. This directional turn suggests
a northward shift in the 850 baroclinic zone towards the area, with
increasing isentropic lift allowing for scattered showers to develop
across southern Nebraska and NE Kansas.
Today: Low level winds will continue to slowly veer this morning as
the shortwave tracks east southeast into central Kansas. Rain
chances will gradually increase through the morning hours as
low-level flow finally turns southwest by mid-late morning.
However, given the track of the shortwave and fairly pronounced
influences of high pressure centered over the Great Lakes, some
questions remain as to how far east rain will track today. Models
suggest highest precip chances will focus themselves during the late
morning through mid-aftn hours.
Tonight: Despite a departing shortwave, an increasing low level jet
should interact with considerable low-mid level moisture in the
region to allow for redevelopment of thunderstorms over west central
Missouri. The prevailing flow should take this activity into the
Ozarks by daybreak Monday.
Monday: The majority of Monday will likely be warm, humid but dry.
Low level thermal ridge axis stretched across the CWA will promote
rather warm temperatures approaching the 90s in some areas. A weak
surface trough and perhaps remnant outflow from overnight convection
will be a focal point for potential thunderstorm development late
Monday afternoon into Monday evening.
.LONG TERM...(Monday Evening through Saturday)
Issued at 323 AM CDT SUN AUG 4 2013
Most models agree on a weak wave tracking across the area Monday
night while a weak low-level jet noses into eastern KS. This could
support another wave of convection Monday evening particularly
across areas south of I-70. Better chances for thunderstorms still
appear in store Tuesday evening and overnight as a cold front moves
through. Better chances for widespread storms will be north of
Highway 36 where the front will arrive sooner and have better
instability to work with. Instability and shear profiles are
supportive of a large convective system with damaging winds coming
out of Nebraska and Iowa, which could survive after dark as far
south as the Missouri River.
Medium range models continue to show a rather extensive surface high
building in from the north Wednesday through Friday. This should act
to keep things mostly dry once lingering storms clear out from north
to south on Wednesday. Boundary should stall over the Ozarks on
Thursday, which could support additional storms across that region
through the end of the week. Better chances for rain through this
time should stay south of the forecast area.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday Morning)
Issued at 626 AM CDT SUN AUG 4 2013
MCS continues to roll across central Kansas this morning, with
scattered showers and thunderstorms beginning to develop on the
eastern edge of precipitation shield. This wave will slide south of the
KC terminals today, but should spread light rain across the KC
terminals in the upcoming few hours. Generally ceilings will remain
VFR, with brief reductions to visibility should heavier showers move
through the area.
As this wave slides into southwestern Missouri this afternoon, it
should also take MVFR ceilings along with it. Can`t rule out
afternoon redevelopment on the backside of this disturbance near the
KS/MO state line, but confidence in coverage and occurrence too low to indicate.
Overnight, a strengthening low level jet will induce scattered
showers once again towards midnight. Feel this area will be focused in
central Missouri, thus will not include in current TAF, but will need
to be monitored.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...MJ
SHORT TERM...Dux
LONG TERM...Hawblitzel
AVIATION...Dux
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1148 PM CDT SAT AUG 3 2013
.UPDATE...
ISSUED AT 933 PM CDT SAT AUG 3 2013
GOING FORECAST STILL LOOKS ON TRACK. SLIGHTLY DRIER AIR CONTINUES
TO ADVECT INTO THE AREA WHICH HAS CAUSED DEWPOINTS TO LOWER THIS
EVENING. SKIES HAVE CLEARED OUT IN MANY LOCATIONS...THOUGH
CONVECTIVE DEBRIS CLOUDS ARE MOVING QUICKLY EASTWARD ACROSS
NORTHERN MO THAT WILL SPREAD ACROSS THE CWA THE NEXT FEW HOURS.
THESE FACTORS SHOULD LIMIT FOG DEVELOPMENT TONIGHT...THOUGH STILL
COULD SEE SOME FORMATION IN LOW LYING AREA. NEAREST THUNDERSTORMS
AT THIS HOUR ARE WELL WEST OF THE CWA IN CENTRAL AND WESTERN
PARTS OF OK/KS. LATEST RAP AND LOCAL WRF RUNS DO NOT BRING ANY LOW
LEVEL MOISTURE CONVERGENCE INTO CENTRAL MO UNTIL AT LEAST MID
MORNING SUNDAY...SO HAVE PUSHED BACK CHANCES OF SHOWERS AND
THUNDERSTORMS UNTIL AT LEAST 15Z.
BRITT
&&
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 324 PM CDT SAT AUG 3 2013
RESIDUAL CLOUD COVER DUE TO THE MCS THAT MOVED SOUTHEASTWARD ACROSS
THE REGION EARLIER TODAY CONTINUES TO DIMINISH...AND WILL ALLOW FOR
PARTLY CLOUDY TO MOSTLY CLEAR SKIES OVERNIGHT. REGARDING
PRECIPITATION CHANCES...HAVE GONE AHEAD AND REMOVED POPS OVERNIGHT
ACROSS SOUTHEASTERN AND CENTRAL MISSOURI. DESPITE ADDITIONAL
CONVECTION EXPECTED TO DEVELOP OVER EASTERN KANSAS AND GROW UPSCALE
INTO ANOTHER MCS...GIVEN THE SOUTHWARD PROGRESSION OF THE COLD FRONT
AND BUILDING HIGH PRESSURE...EXPECT THE PROPAGATION OF THE
CONVECTION TO HAVE A MORE SIGNIFICANT SOUTHERLY COMPONENT THAN SHOWN
BY THE MCS LAST NIGHT. RECENT MODEL OUTPUT FROM THE GFS...NAM...AND
ECMWF ECHO THIS IDEA WITH LITTLE IF ANY QPF ANYWHERE OVER THE CWA
PRIOR TO 12Z SUNDAY. THUS...A TRANQUIL EVENING IS EXPECTED ACROSS
THE AREA TONIGHT...WITH LOW TEMPERATURES RANGING FROM THE UPPER 50S
TO MID 60S...SLIGHTLY BELOW NORMAL FOR THIS TIME OF YEAR.
JP
TRUETT
.LONG TERM...(SUNDAY THROUGH NEXT SATURDAY)
ISSUED AT 324 PM CDT SAT AUG 3 2013
AS WE HEAD INTO THE NEW WEEK...QUESTION BECOMES WHEN AND HOW HARD TO
HIT RETURN OF TSRA CHANCES ACROSS THE REGION. AS MENTIONED IN THE
SHORT TERM PORTION OF THE DISCUSSION STRONG INTRUSION OF SURFACE
HIGH TODAY AND TONIGHT...COUPLED WITH EFFECTS OF RAIN-COOLED AMS
FROM LAST NIGHTS MCS...HAS ALLOWED THE BEST INSTABILITY AND
BAROCLINICITY TO MAKE A SUBTLE BUT SIGNIFICANT SW SHIFT.
SO...WHILE THE E FRINGES OF OVERNIGHT CONVECTION MAY BE APPROACHING
OUR W COUNTIES ON SUNDAY MORNING...THE MORE STABLE AND DRIER AIR MAY
CAUSE THE PRECIP TO STRUGGLE TO MAKE TOO MUCH HEADWAY INTO OUR
CWA...ESPECIALLY SINCE LOW LEVEL FLOW MAINTAINS A FAIRLY
PRONOUNCED S COMPONENT THROUGHOUT THE DAY.
HOWEVER...ALL SYNOPTIC MODELS ARE FORECASTING THE LOW LEVEL JET TO
VEER AND BECOME FOCUSED ACROSS THE AREA SUNDAY NIGHT AS SURFACE
RIDGE RETREATS TO THE EAST. THIS WILL TRANSPORT INCREASINGLY MOIST
AND UNSTABLE AIR INTO THE REGION AND INDUCE ISENTROPIC ASCENT OVER
MOST OF NOT ALL OF THE CWA....LEADING TO A THREAT OF NOCTURNAL
CONVECTION FOR MOST OF THE AREA BY DAYBREAK MONDAY. ONCE THE
TSRA CHANCES RETURN SUNDAY NIGHT...IT WOULD APPEAR THAT A
THUNDERSTORM THREAT WILL REMAIN LOCKED OVER THE MID MISSISSIPPI
VALLEY THROUGH MIDWEEK AS DISTURBANCES IN THE NW MID LEVEL FLOW
WILL INTERACT WITH THE MOIST AND UNSTABLE AIRMASS THAT WILL BE
PARKED OVER THE CENTRAL CONUS.
PATTERN IS CERTAINLY ONE THAT COULD LEAD TO A SERIES OF
CONVECTIVE COMPLEXES TO PROPAGATE ACROSS THE AREA THROUGH TUESDAY.
AS IS TYPICAL MODELS ARE VARYING IN THE SPECIFICS OF
FORCING/THERMODYNAMICS AND EVOLUTION OF CONVECTION...BUT HAVE
BASED FORECAST TRENDS MORE ON EXPECTED SYNOPTIC PATTERN THAN ON
THE SPECIFICS OF ANY ONE MODEL. FOR NOW HAVE GONE WITH MIDDLE OF
THE ROAD CHANCE POPS...BUT FULLY EXPECT THAT THERE WILL BE LARGER
SWINGS IN POP NUMBERS AS THE DETAILS/TIMING OF EACH POTENTIAL MCS
BECOMES A BIT CLEARER IN THE NEAR TERM.
OBVIOUSLY...TEMPERATURE SPECIFICS WILL BE HIGHLY DEPENDENT ON TIMING AND
EXTENT OF CONVECTION...BUT FOR NOW HAVE MAINTAINED HIGHS IN THE
80S AND LOWS IN THE UPPER 60S TO LOWER 70S.
MEDIUM RANGE SOLUTIONS ARE NOW FORECASTING AN UPPER LOW TO DIP
INTO S CANADA AND CLIP THE UPPER GREAT LAKES DURING THE LATTER
HALF OF THE WEEK. LEAD SHORTWAVE AND ASSOCIATED COLD FRONT WILL
WORK ACROSS THE REGION WEDNESDAY AND INTO WEDNESDAY EVENING
CONTINUING A THREAT OF SHOWERS AND THUNDERSTORMS. HOWEVER...12Z GFS
AND ECMWF NOW SUGGESTING THAT PRIMARY BAROCLINIC ZONE WILL BE
SHIFTED INTO S MO AND N AR BY THE END OF THE WORK WEEK WITH COOLER
AND MORE STABLE DROPPING S INTO THE N AND MID MISSISSIPPI VALLEY.
BASED ON THIS PATTERN SHIFT HAVE LIMITED CHANCE POPS TO S SECTIONS
OF THE CWA ON THURSDAY AND FRIDAY.
TEMPERATURES DURING THE EXTENDED MAY NOT BE TOO MUCH DIFFERENT
THAN THOSE OF EARLY IN THE WEEK...BUT HUMIDITY LEVELS SHOULD BE LOWER.
TRUETT
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1141 PM CDT SAT AUG 3 2013
EXPECT VFR FLIGHT CONDITIONS TO PREVAIL FOR THE REST OF THE
NIGHT...EXCEPT IN LOCALIZED AREAS IN RIVER VALLEYS. THINK
RELATIVELY THICK CIRRUS OVER THE AREA SHOULD KEEP FOG TO A
MINIMUM...THO MVFR AND EVEN SOME PATCHY IFR IS STILL POSSIBLE IN
THE RIVER VALLEYS. SOME SHORT RANGE GUIDANCE IS HINTING THAT AN
AREA OF SHOWERS AND THUNDERSTORMS MAY AFFECT PARTS OF CENTRAL
MISSOURI AFTER 12Z...BUT THERE SEEMS TO BE NO CONSENSUS YET ON THE
LOCATION OF THE PRECIPITATION...MOST MODELS ARE KEEPING IT FURTHER
TO THE SOUTHWEST. WILL ADD IN VCSH TO THE KCOU TAF SUNDAY
MORNING...BUT AM NOT VERY CONFIDENT IN THE PLACEMENT OF THE
PRECIPITATION. EXPECT THE REMAINDER OF THE AREA TOR REMAIN DRY
WITH VFR CONDITIONS SUNDAY INTO SUNDAY EVENING.
SPECIFICS FOR KSTL...
VFR FLIGHT CONDITIONS WILL CONTINUE TO PREVAIL AT LAMBERT. THERE
COULD BE SOME SHOWERS AND STORMS FIRING UP EARLY SUNDAY MORNING
OVER CENTRAL MISSOURI...BUT I EXPECT ANY STORMS THAT DO FORM TO
REMAIN WELL WEST OF THE TERMINAL.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
258 PM MDT SUN AUG 4 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH TUESDAY...
AS THE REMNANTS OF THE SHEARED LOW PRESSURE SYSTEM FROM THE
PACIFIC NORTHWEST FIZZLES OUT ALONG THE MONTANA-SASKATCHEWAN
BORDER...VERY SMALL ISOLATED RAIN SHOWERS ARE GETTING A START
ACROSS A FEW PORTIONS OF NORTHEAST MONTANA. THE HRRR MODEL
CONTINUES TO IGNORE THE THIN BAND OF LIGHT RAIN SHOWERS FROM
JORDAN TO CIRCLE TODAY...BUT IS PERSISTENT IN SUPPORTING A LARGER
CLUSTER OF THUNDERSTORMS MOVING FROM NORTHERN PHILLIPS COUNTY
SOUTHEASTWARD THROUGH THE FORT PECK AREA LATER THIS AFTERNOON AND
EVENING. TRIED TO BETTER REPRESENT THESE TRENDS IN THE FORECAST
GRIDS AND PLAN TO ISSUE THE FORECAST WITH A PRE-FIRST PERIOD TO
REPRESENT THIS THINKING TO THE PUBLIC.
TONIGHT...UPPER LEVEL FLOW OVER MONTANA SHOWS A VERY SMALL SCALE
RIDGE INFLUENCE FROM THE SOUTH BETWEEN SYSTEMS BEFORE THE FLOW OVER
OUR REGION FALLS UNDER GREATER INFLUENCE FROM THE LARGE UPPER LOW
COMPLEX TOWARDS THE NORTHEAST...COURTESY OF THE RELATIVELY ARCTIC
INTRUSION FROM THE HUDSON BAY REGION. THE ATTENDANT COLD FRONT
WILL MOVE THROUGH OUR CWA SOMETIME TUESDAY AFTERNOON AND WILL
RESULT IN ABOUT A 10 DEGREE DROP IN DAYTIME TEMPERATURES THROUGH
MOST OF THE WORK WEEK.
AFTER A DRY MONDAY MORNING TOMORROW...THIS OTHER STEERING
INFLUENCE WILL INTRODUCE PERIODS OF SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH PORTIONS OF THE CWA THROUGH THE REMAINDER OF
THE FORECAST PERIOD. FORCING FOR ASCENT WILL REMAIN NEUTRAL OR
MINIMAL AT BEST AND NO SIGNIFICANT WEATHER SYSTEMS ARE EXPECTED TO
IMPACT THE REGION. BMICKELSON
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...
UPDATE...VERY LITTLE CHANGE IN THE EXTENDED FORECAST. GUIDANCE
KEEPS WITH THE PREVIOUS FORECAST. DID ADD VERY LOW POPS TO THE END
OF THE FORECAST WITH THE SPREAD OF THE GUIDANCE BEING ENOUGH TO
BRING A SLIM CHANCE OF PRECIPITATION. THE ONLY MAJOR CHANGE OTHER
THAN BRUSHING UP THE EDGES WITH CHANGES MADE AROUND THE REGION. PROTON
SYNOPTIC SET UP A CLOSED LOW EXISTS OVER THE THE ONTARIO/MANITOBA
BORDER WITH A COLD FRONT EXTENSION OVER THE UPPER MISSISSIPPI
VALLEY THE NORTHERN US PLAINS AND THE CENTRAL US HIGH PLAINS. COLD
AIR BEHIND THE FRONT WILL SMASH THE INTENSITY OF THE LARGE HEAT
DOME OVER THE FOUR CORNERS AND REDUCING IT TO A RIDGE OVER THE
INTER-MOUNTAIN WEST AND BRITISH COLUMBIA. A LARGE TROUGH IS
DEVELOPING OVER THE GULF OF ALASKA WITH A FAR WEAKER TROUGH OFF
THE COAST OF CALIFORNIA AND THE PACIFIC NORTHWEST.
TUESDAY NIGHT THROUGH FRIDAY... NORTHEAST MONTANA LIES IN A ZONAL
TO NORTHWEST FLOW PATTERN WITH WEAK SHORTWAVES COMING ACROSS ON A
REGULAR BASIS. TIMING OF THE WAVES IS DIFFICULT. HOWEVER... THE
TROUGH OVER ONTARIO AND MANITOBA WILL SEND A COLD FRONT DOWN
THROUGH THE AREA WEDNESDAY EVENING. TEMPERATURES ARE ANTICIPATED
TO COOL OFF BY ABOUT 10 DEGREES POST FRONT FOR HIGHS AND LOWS
WITH THE AFFECT LINGERING THROUGH FRIDAY EVENING. CHANCES FOR RAIN WILL
EXIST ALONG AND BEHIND THE FRONT.
SATURDAY ONWARD... THE LARGE TROUGH OVER ONTARIO WILL PUSH EAST
INTO QUEBEC ALLOWING THE LARGE RIDGE TO THE WEST TO GAIN
INCREASING DOMINION OVER THE NORTHEAST MONTANA WEATHER PATTERN.
EXPECTED TEMPERATURES TO CREEP UPWARDS TO NEAR NORMAL AGAIN WITH
CHANCES FOR RAIN DROPPING SLOWLY. GAH
&&
.AVIATION...
VFR FOR MOST LOCATION THROUGH THE PERIOD. MVFR REMAINS NEAR THE
YELLOWSTONE RIVER AND MISSOURI RIVE CONFLUENCE AREA EARLY THIS
AFTERNOON. THIS AREA OF MVFR SHOULD LIFT TO AN IFR CEILING AROUND
21Z THIS AFTERNOON. CONVECTIVE SHOWERS ARE DOTTED AROUND THE
REGION THIS AFTERNOON...THEREFORE A BRIEF SHOT OF MVFR WITH THESE
SHOWERS ARE POSSIBLE IF THEY HIT A TAF SITE...HOWEVER THE
PROBABILITY OF THIS IS TOO LOW TO PUT INTO THE FORECAST AT THIS
TIME. PROTON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS BILLINGS MT
245 PM MDT SUN AUG 4 2013
.SHORT TERM...VALID FOR MON AND TUE...
WATER VAPOR IMAGERY SHOWS WEAK PV MAX MOVING THROUGH NE MT NOW.
THIS ENERGY IS STRUGGLING TO PRODUCE MUCH IN THE WAY OF CONVECTION
AS THE EASTERN MT AIRMASS IS A BIT DRIER AND CERTAINLY MORE CAPPED
THAN YESTERDAY WITH WEAK COLD ADVECTION UNDERWAY. A WEAK
THUNDERSTORM DID DEVELOP OVER THE SNOWY MTNS BUT THIS CELL HAS NOT
BEEN ABLE TO DETACH FROM THE HIGH TERRAIN SO FAR. ASCENT FROM
AFOREMENTIONED SHORTWAVE IS GREATEST IN FAR EASTERN MT THIS
AFTERNOON...WITH DESCENT EXPECTED BY EVENING...SO FORCING IS
MINIMAL. NOT EXPECTING TOO MUCH ACTIVITY INTO THIS EVENING BUT
FOCUS OF POTENTIAL STRONGER TSTMS MAY BE ALONG THE MT/WY BORDER
FROM SHERIDAN COUNTY EASTWARD...IN AN AREA OF HIGHER THETA-E AIR
AND A BIT MORE FAVORABLE LOW LEVEL WIND SHEAR NEAR STALLED SFC
BOUNDARY. HRRR RUNS HAVE BEEN CONSISTENT IN KEEPING DEVELOPMENT
MAINLY IN NE WY...WITH ONLY VERY WEAK CELLS FURTHER NORTH. WILL
KEEP POPS IN LINE WITH THIS THINKING...AND WILL CONTINUE TO
ADVERTISE THE POSSIBILITY OF A STRONGER STORM NEAR THE SE MT/WY
BORDER INTO THE EARLY EVENING. EVENING ACTIVITY SHOULD BE DONE BY
SUNSET AND THE REMAINDER OF THE NIGHT SHOULD BE DRY WITH A TREND
TOWARD RIDGING ALOFT.
HEIGHTS BEGIN TO FALL AGAIN BY TOMORROW AFTERNOON AS BRITISH
COLUMBIA SHORTWAVE DROPS INTO WESTERN MT. SFC HEATING WILL
DESTABILIZE THE AIRMASS ENOUGH TO ALLOW FOR SOME LATE AFTERNOON
AND EVENING SHOWER/TSTM ACTIVITY...WITH ENHANCEMENT BY EVENING
WITH A FRONTAL PASSAGE...THOUGH WITH A DRIER PREFRONTAL AIRMASS
AS WE MIX W-NW MID LEVEL WINDS. FOCUS OF POTENTIAL STRONGER STORMS
WILL AGAIN BE IN FAR SOUTHEAST MT WHERE MOISTURE/INSTABILITY WILL
BE GREATEST ALONG WEAK SFC TROF/AREA OF PRESSURE FALLS. HAVE
RAISED POPS TO SCATTERED ACROSS MUCH OF THE AREA BY MONDAY NIGHT
PER FORCING FROM THE BC SHORTWAVE.
EXPECT ISOLATED SHOWERS/TSTMS ON TUESDAY UNDER CYCLONIC NW FLOW
ALOFT...BUT WITH NOTHING STRONG OR SEVERE AS DEEP MOISTURE/
INSTABILITY AXIS WILL BE SHIFTED WELL INTO THE CENTRAL PLAINS.
TEMPERATURES ON MONDAY WILL JUMP UP WITH PREFRONTAL WARMING AND A
PERIOD OF DOWNSLOPE WINDS. SHOULD SEE TEMPS NEAR 90 DEGREES FOR
THE FIRST TIME IN AWHILE. TUESDAY WILL BE SEVERAL DEGREES COOLER
THOUGH...AND BACK BELOW NORMAL...IN A POST FRONTAL REGIME WITH
SOMEWHAT GUSTY NW WINDS.
JKL
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
NO SIGNIFICANT CHANGES WERE MADE TO THE EXTENDED PERIOD FOR THIS
FORECAST PACKAGE. MODELS CONTINUE TO BE CONSISTENT WITH A
POWERFUL UPPER LOW OVER THE HUDSON BAY AREA DIRECTING OUR OVERALL
WEATHER PATTERN. THIS KEEPS US IN QUASI CYCLONIC TO NORTHWEST FLOW
ALOFT WITH OCCASIONAL BACK DOOR COLD FRONTS SLIPPING INTO EASTERN
MONTANA. THE TIMING AND STRENGTH OF THESE FRONTS ARE IN QUESTION
AS THE GFS AND ECMWF OFFER SOMEWHAT DIFFERENT SOLUTIONS. MAIN
THEME THOUGH IS SAME...COOLER THAN NORMAL AND AT LEAST SOMEWHAT
UNSETTLED. BT
&&
.AVIATION...
EXPECT PARTLY CLEAR SKIES THIS EVENING WITH A SLIGHT CHANCE FOR A
SHOWER OR THUNDERSTORM...MAINLY OVER ROUTES FROM KSHR EASTWARD.
EXPECT MVFR CONDITIONS IN AND NEAR ANY THUNDERSTORM ACTIVITY.
OTHERWISE...VFR CONDITIONS WILL PREVAIL OVERNIGHT. BT
&&
.PRELIMINARY POINT TEMP/POPS...
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 058/090 059/081 057/084 058/079 057/081 058/085 059/086
22/T 32/T 21/U 12/T 22/T 22/T 22/T
LVM 052/088 050/084 051/084 052/083 051/082 051/086 052/086
22/T 32/T 21/B 12/T 22/T 23/T 22/T
HDN 056/092 058/084 054/085 057/081 057/084 058/087 059/088
22/T 32/T 21/U 11/B 22/T 22/T 22/T
MLS 057/091 060/080 056/083 057/079 055/082 058/086 061/087
22/T 32/T 11/U 21/B 22/T 22/T 22/T
4BQ 056/090 058/081 052/083 054/081 053/081 056/085 058/087
32/T 32/T 11/U 11/B 22/T 22/T 22/T
BHK 053/087 058/076 049/077 052/075 051/077 053/079 056/080
22/T 32/T 11/U 21/U 12/T 21/B 22/T
SHR 055/091 055/083 052/084 053/082 053/083 055/087 056/088
32/T 32/T 21/U 22/T 22/T 22/T 22/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
951 AM MDT SUN AUG 4 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH TUESDAY...
SENT A MINOR FORECAST UPDATE THIS MORNING. ALTHOUGH GENERAL
THUNDERSTORMS ARE EXPECTED FOR OUR ENTIRE CWA ON THE NATIONAL
LEVEL...MULTIPLE SMALLER SCALE AND HIGH RESOLUTION PRODUCTS
INDICATE THAT CENTRAL AND SOUTHERN PORTIONS OF OUR CWA WILL BE
QUIET TODAY. I ADJUSTED THE POPS AND WEATHER GRIDS BY CUTTING THEM
BACK TO SILENT...FOLLOWING THE MAJORITY OF MODEL CONSENSUS I COULD
FIND. MODEL FORCING FOR ASCENT SHOWS NEUTRAL BEING REPLACED BY
SUBSIDENCE LATER ON THIS AFTERNOON AND EVENING. THE HRRR MODEL
DOES SHOW SOME AFTERNOON SHOWERS AND THUNDERSTORMS BUT THEY DO NOT
REACH MUCH FURTHER SOUTH THAN NEAR FORT PECK LAKE AND THE MISSOURI
RIVER EASTWARD. BMICKELSON
PREVIOUS SHORT TERM DISCUSSION...SPLITTING UPPER TROF OVER THE
PACIFIC NORTHWEST WEST WILL BE THE MAIN WEATHER FEATURE FOR THE
NEXT 24 TO 36 HOURS. AT THAT POINT THE UPPER LOW OVER HUDSON BAY
DROPPING INTO CENTRAL CANADA WILL DOMINANT THE NORTHERN PLAINS.
LIGHT WINDS AND MOISTURE LINGERING OVER THE REGION FROM YESTERDAYS
STORMS ALLOWING SOME LOW CLOUDS AND FOG TO FORM THIS MORNING. WITH
ANOTHER SHORTWAVE MOVING INTO THE STATE TODAY...TO ENCOUNTER THE
MOISTURE UNSTABLE AIR MASS OVER EASTERN MONTANA...EXPECT A FEW
THUNDERSTORMS IN THE AFTERNOON.
A SLIGHTLY DRIER RIDGE DEVELOPS TONIGHT BEFORE BEING SUPPRESSED BY
SHORTWAVE SLIDING DOWN THE CANADIAN ROCKIES ON MONDAY. THIS WAVE
HELPS TO PULL THE HUDSON BAY LOW WESTWARD INTO MANITOBA BY
TUESDAY. CANADIAN SHORTWAVE PUSHES COLD FRONT THROUGH NORTHEAST
MONTANA LATE MONDAY WITH SHOWERS AND A FEW THUNDERSTORMS. ENOUGH
INSTABILITY LINGERS WITH THE COOLER AIR FOR ADDITIONAL SHOWERS ON
TUESDAY. EBERT
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...
SYNOPTIC SET UP A CLOSED LOW EXISTS OVER THE THE ONTARIO/MANITOBA
BORDER WITH A COLD FRONT EXTENSION OVER THE UPPER MISSISSIPPI
VALLEY THE NORTHERN US PLAINS AND THE CENTRAL US HIGH PLAINS.
COLD AIR BEHIND THE FRONT WILL SMASH THE INTENSITY OF THE LARGE
HEAT DOME OVER THE FOUR CORNERS AND REDUCING IT TO A RIDGE OVER
THE INTER-MOUNTAIN WEST AND BRITISH COLUMBIA. A LARGE TROUGH IS
DEVELOPING OVER THE GULF OF ALASKA WITH A FAR WEAKER TROUGH OFF THE
COAST OF CALIFORNIA AND THE PACIFIC NORTHWEST.
TUESDAY NIGHT THROUGH FRIDAY... NORTHEAST MONTANA LIES IN A ZONAL
TO NORTHWEST FLOW PATTERN WITH WEAK SHORTWAVES COMING ACROSS ON A
REGULAR BASIS. TIMING OF THE WAVES IS DIFFICULT. HOWEVER... THE
TROUGH OVER ONTARIO AND MANITOBA WILL SEND A COLD FRONT DOWN
THROUGH THE AREA WEDNESDAY EVENING. TEMPERATURES ARE ANTICIPATED
TO COOL OFF BY ABOUT 10 DEGREES POST FRONT FOR HIGHS AND LOWS
WITH THE AFFECT LINGERING THROUGH FRIDAY EVENING. CHANCES FOR RAIN WILL
EXIST ALONG AND BEHIND THE FRONT.
SATURDAY ONWARD... THE LARGE TROUGH OVER ONTARIO WILL PUSH EAST
INTO QUEBEC ALLOWING THE LARGE RIDGE TO THE WEST TO GAIN
INCREASING DOMINION OVER THE NORTHEAST MONTANA WEATHER PATTERN.
EXPECTED TEMPERATURES TO CREEP UPWARDS TO NEAR NORMAL AGAIN WITH
CHANCES FOR RAIN DROPPING SLOWLY. GAH
&&
.AVIATION...
AREAS OF MVFR WITH SOME LOCALIZED IFR...THIS SHOULD ALL BECOME VFR
BY 18Z. 12Z SOUNDING AT KGGW SHOWS THE INVERSION THAT IS CREATING
THE LOW CEILINGS AND FOG TO BE AROUND 3200 AGL...WITH A BURN OFF
TEMPERATURE AROUND 72 WHICH SHOULD LINE UP WITH MID DAY. THEN JUST
SOME LIGHT CONVECTIVE ACTIVITY FOR THE AFTERNOON HOURS. PROTON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
345 PM CDT SUN AUG 4 2013
.SYNOPSIS...
LITTLE CHANGE TO THE OVERALL PATTERN IN THE LAST 24 HOURS. UPPER
LEVEL RIDGE REMAINS CENTERED OVER NW TX. SEVERAL SHORT WAVES RIDING
AROUND THE PERIPHERY OF THE RIDGE...WITH GOOD TAP TO TROPICAL
MOISTURE. AT THE SFC SOUTHEASTER FLOW CONTINUES TO PUMP MOISTURE
INTO THE REGION. DEW PTS HAVE CREPT UP INTO THE MID 60S...WITH LOWER
70S ACROSS MUCH OF KANSAS.
&&
.DISCUSSION...
TONIGHT...THE NEXT SHORT WAVE RIDING ACROSS THE CENTRAL ROCKIES
WILL BE THE FOCUS FOR CONVECTION ALONG THE FRONT RANGE. SOME
UNCERTAINTY TO THE SUSTAINABILITY FOR THE STORMS AS THEY MOVE OFF
THE HIGHER TERRAIN. THE HRRR SUGGESTS THE STORMS WILL MAKE IT INTO
WESTERN NEBRASKA...WHILE THE NAM/RUC FAVOR NORTHERN NEB...UTILIZED
THE BLACK HILLS FOR INITIATION. THE NOSE OF THE LL JET OVERNIGHT
FOCUSES NEAR THE NEB/S DAKOTA BORDER AND WILL FAVOR THE NORTHERN
ZONES WITH THE HIGHEST POPS. LOW LEVEL MOISTURE REMAINS EXCELLENT
AND GUIDANCE IN AGREEMENT WITH LOW CLOUDS TO CONTINUE/REDEVELOP
ACROSS THE AREA OVERNIGHT. COULD SEE SOME FOG ACROSS SW NEB AS DEW
POINTS ARE UP A FEW DEGREES FROM THE PAST COUPLE OF DAYS AND
EXPECT TO EASILY SEE 100 PERCENT RH AS TEMPS COOL INTO THE LOWER
TO MID 60S...HOWEVER THE LATEST MOS GUIDANCE HOLD VSBY IN THE 4 TO
6 MILE RANGE AND FORECAST FAVORS THE LOW STRATUS WITH POCKETS OF
FOG. NOT EXPECTING FOG TO BE WIDESPREAD ENOUGH AT THIS TIME TO
INCLUDE IN FORECAST...HOWEVER WILL MONITOR.
MONDAY...LINGERING THUNDERSHOWERS ACROSS NORTH CENTRAL NEBRASKA
SHOULD DECAY IN THE MORNING WHILE STRATUS ELSEWHERE WILL BE SLOW TO
ERODE. ANOTHER SHORT WAVE...A STRONGER SYSTEM...WILL ENTER THE
REGION FOR THE AFTERNOON. AS THE CLOUDS FINALLY BEGIN TO BREAK AND
TEMPS QUICKLY BUMP INTO THE 80S WITH A FEW LOWER 90S ACROSS THE
SW...GROWING INSTABILITY SHOULD BE ENOUGH FOR CONVECTION. SPC HAS
A SLGHT RISK IN PLACE FOR WESTERN NEBRASKA AND AGREE WITH 40 TO
50 KTS OF SHEAR WITH DEW PTS IN THE 60S. THUNDERSTORMS SHOULD
BREAK THE CAP IN THE AFTERNOON. PRECIPITABLE WATER AROUND 130 TO
150 PERCENT OF NORMAL SHOULD BE SUFFICIENT FOR LOCALLY HEAVY
RAINFALL.
MONDAY NIGHT THROUGH WEDNESDAY...DESPITE THE DEEP MOISTURE...THE
MODELS ARE BACKING OFF ON ANY SORT OF WIDESPREAD HP EVENT LATE
MONDAY. IT MAY BE THAT THE CAP IS VERY STRONG IN THE LATEST SOLNS
SHOWING A STRENGTHENING CAP OF 12C TO 14C AT 700 MB ACROSS WRN NEB
AND THE UPPER LEVEL FORCING IS WEAK MONDAY. MODEL BLENDED POPS ARE
AROUND 30 PERCENT AND QPF IS LESS THAN 1/10 OF AN INCH FOR MONDAY
NIGHT.
ON TUESDAY A COLD FRONT WILL DROP THROUGH THE FCST AREA PROVIDING
FOCUS FOR STORM DEVELOPMENT. THE 00Z WEDNESDAY MODEL CONSENSUS SHOWS
THE SFC LOW ACROSS SWRN KS WHICH IS A POST FRONTAL ENVIRONMENT FOR
POPS ACROSS THE FCST AREA. THE GEM...GFS AND ECM ARE KEYING ON
MOISTURE TRAPPED BEHIND THE COLD FRONT ACROSS ERN PTNS OF NCNTL NEB
WHERE THE CAP WILL BE WEAKEST. POPS ARE 40 PERCENT THERE IN THE AFTN
BUT FALL OFF TUESDAY EVENING AS A MCS DROPS SOUTH THRU CNTL AND ERN
NEB.
ALL MODELS SHOW A 12C-14C CAP ACROSS SWRN NEB TUESDAY WHICH IS LIKELY
LIMITING CONVECTION. THIS THERMAL RIDGE WILL DROP SOUTH LATE TUESDAY
AFTN WHICH COULD OPEN UP THE FCST AREA TO MORE WIDESPREAD CONVECTION
THAN INDICATED BY THE MODELS. THE FRONT WILL DROP SOUTH ON THE HEALS
OF A 300 MB JET IN COMBINATION WITH A DEEP UPPER LEVEL LOW DROPPING
THROUGH MANITOBA. THIS PRODUCES 45 TO 55 KT OF 0-6KM BULK SHEAR
TUESDAY AFTN WITH ML CAPE OVER 3000J/KG EAST OF HIGHWAY 83. THE
SHEAR AND CAPE VALUES ARE MUCH WEAKER MONDAY EVENING SO THE BEST
CHANCE FOR SEVERE WEATHER IS TUESDAY ALONG AND EAST OF HIGHWAY 83.
THE DEEP UPPER LEVEL CYCLONE DROPPING THRU MANITOBA WILL PUSH A
STRONG COLD FRONT THROUGH THE FCST AREA WEDNESDAY AND HIGH TEMPS
WILL STRUGGLE TO REACH 80F. HIGHS TUESDAY RISE INTO THE LOWER 90S
SOUTH WITH THE THERMAL RIDGE OVERHEAD. 80S ARE EXPECTED ELSEWHERE.
ANY CONVECTION THAT FIRES SHOULD BE MOSTLY SOUTH AND WEST OF THE
FCST AREA. THERE IS A GLITCH IN THE FORECAST THOUGH. THE 18Z NAM
IS LIFTING A SUBTROPICAL SHORT WAVE THROUGH SWRN NEB WEDNESDAY
AFTN. THE GEM...ECM AND GFS MOVE THIS WAVE THROUGH KS SOUTH OF THE
FCST AREA. FOR THE FCST USES THE CONSENSUS WHICH IS FOR ISOLATED
STORMS ACROSS THE SOUTH WEDNESDAY.
WEDNESDAY NIGHT THROUGH SUNDAY...A NEW DEVELOPMENT IN THE 12Z MODEL
RUNS IS THEY ARE NOT NEARLY AS STRONG WITH A REINFORCING COLD FRONT
THAT WAS FCST TO PULL VERY COOL AIR SOUTH OUT OF CANADA. THE GFS
ENSEMBLE HOLDS THE HIGH ACROSS MANITOBA AND SASKATCHEWAN WITH A
STATIONARY FRONT DRAPED ACROSS THE CNTL PLAINS. IN FACT THE FCST AREA
REMAINS UNDER SOUTH AND SOUTHEAST WINDS AT 850 MB. NOW THE ALLBLEND
TOTAL QPF FOR THIS PERIOD SHOWS AROUND 1 INCH ACROSS SCNTL NEB TO
LESS THAN 1/4 OF AN INCH ACROSS WRN/NRN NEB SUGGESTING A STATIONARY
FRONT WILL OPERATE ACROSS THE FCST AREA. POPS ARE STILL ISOLATED TO
SCATTERED AND TEMPS ARE A BIT WARMER...UPPER 70S TO LOWER 80S. IT
WOULD APPEAR THAT THE SOUTHERLY WINDS ARE BACKED AROUND THE MANITOBA
HIGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 111 PM CDT SUN AUG 4 2013
MVFR TO IFR CIGS WILL SEE MORE AND LARGER POCKETS OF VFR CIGS AS
CLOUDS ERODE WITH HEATING OF THE AFTERNOON. LAST TO LIFT IS ALONG
THE HIGHER TERRAIN ACROSS WESTERN NEBRASKA. WITH THE DECREASING
CLOUDS AND WARMING TEMPERATURES...AN ISOLATED THUNDERSTORM IS
POSSIBLE...MAINLY ACROSS WESTERN NEBRASKA...HOWEVER ACTIVITY MAY
REMAIN CLOSER TO THE FRONT RANGE.
TONIGHT A RETURN OF THE LOWER MVFR/IFR CIGS IS EXPECTED. LOCALLY
SOME REDUCED VSBY FROM FOG IS ALSO POSSIBLE. A SHORT WAVE WILL
BRING A SLIGHT CHANCE FOR SOME ISOLD TO SCT STORMS. MODELS VARY ON
LOCATION AND WITH THE MAJORITY IMPACTING NORTHERN NEBRASKA...THUS
HAVE INCLUDED VCTS IN THE KVTN TAF...AND WILL LOOK TO UPDATE AND
TIMING BECOMES MORE DEFINED.
BY TOMORROW MORNING THE LOWER CIGS WILL SLOWLY LIFT...WITH A FEW
LINGERING ISOLD STORMS POSSIBLE. PROBABILITY IS TO LOW TO INCLUDE
IN EITHER TAF AT THIS TIME. WINDS THROUGH THE PERIOD WILL
GENERALLY BE SOUTHEASTERLY TO SOUTHERLY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...MASEK
LONG TERM...CDC
AVIATION....MASEK
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
632 PM MDT MON AUG 5 2013
.AVIATION...
00Z TAF CYCLE
AN ACTIVE EVENING. CARRYING A COUPLE OF HOURS OF TEMPO FOR TS
EARLY THIS EVENING ALL TAF SITES EXCEPT KROW. NO MVFR BUT CANT
RULE OUT BRIEF MVFR CIGS AND VSBYS AND MT OBSCURATIONS. MOST
OF THE CONVECTION WILL BE OVER BY 06Z. VFR CONDITIONS 06Z TO
18Z TUE. NEXT CROP OF CONVECTION TUESDAY MAY BE EVEN MORE
WIDESPREAD THAN TODAY. WILL CARRY VCTS ALL TERMINALS TUE PM
EXCEPT KTCC AND KROW WHERE CHANCES WILL BE LOWEST.
&&
.PREV DISCUSSION...244 PM MDT MON AUG 5 2013...
LESS ACTIVE TODAY THAN AT THIS TIME YESTERDAY. SHOWERS AND STORMS
WITH LOCALLY HVY RAIN ARE STILL DEVELOPING OVER THE NORTHERN AND
WESTERN HIGH TERRAIN AND EASTERN HIGH PLAINS. STORM MOTIONS ARE
FASTER AND MORE TO THE NORTHEAST. LAPS PARAMETERS STILL INDICATE
POTENTIAL FOR A FEW STRONG STORMS ARE FLASH FLOODING IS NOT OUT
OF THE QUESTION FOR ANY AREA. RUC GUIDANCE AGAIN SHOWS ACTIVITY
MERGING INTO THE RGV THIS VALLEY HOWEVER CONFIDENCE NOT AS HIGH
SINCE OTHER GUIDANCE MEMBERS KEEP ALL ACTIVITY FARTHER SOUTH AND
THERE IS A LESS THAN IMPRESSIVE CU FIELD OVER THE AREA ATTM. THE
INTERESTINGLY THERE IS A WELL DEFINED WAVE THAT HAS DEVELOPED IN
THE MONSOONAL PLUME HEADING NORTH INTO THE NM BOOTHEEL. FOR THIS
REASON HAVE KEPT A LARGER THAN TYPICAL AREA OF CHANCE POPS FOR
THE OVERNIGHT.
THE NEXT VERY WELL DEFINED WAVE IS POISED OVER THE BAJA REGION
AND THIS WILL MOVE NORTH THROUGH THE MONSOON PLUME TUESDAY. TOTAL
BLENDED PWAT VALUES PER CIRA IMAGERY WITH THIS WAVE ARE IN THE
2.25-2.50 RANGE. 12Z GFS INDICATES THE MAX THETA-E WAVE ASSOCIATED
WITH THIS SYSTEM WILL SLIDE OVER CENTRAL AND WESTERN NM NOW...
WHICH IS A LITTLE FARTHER EAST THAN PREVIOUS RUNS. STORM MOTIONS
WILL BE FASTER TO THE NE BUT FLASH FLOODING IS STILL A CONCERN.
THIS UPPER WAVE WILL GET CAUGHT UP IN INCREASING WESTERLY FLOW
OVER THE CENTRAL ROCKIES THEN NW FLOW OVER THE GREAT PLAINS.
A BACK DOOR FRONTAL BOUNDARY WILL BE FORCED SOUTHWARD INTO THE NE
PLAINS BEHIND THESE UPPER DYNAMICS. VERY MOIST UPSLOPE FLOW WILL
IMPACT THE SANGRES EASTWARD ACROSS THE PLAINS AND GIVEN LATEST
ROUNDS OF HEAVY RAINFALL IN THIS AREA...THE FLASH FLOOD THREAT
WILL BE QUITE HIGH. WEDNESDAY NIGHT EXPECTING TO SEE A LARGE RAIN
SHIELD SHIFTING SOUTHEAST OVER THE EAST...FOLLOWED BY A DRIER DAY
FOR THURSDAY. TEMPS WILL BE BELOW NORMAL THROUGH THE WHOLE PERIOD.
THE FRIDAY THROUGH MONDAY PERIOD LOOKS INTERESTING WITH ANOTHER
MONSOON BURST POSSIBLE DURING THIS TIME OVER CENTRAL AND WESTERN
NM. MODEL CONSISTENCY ON TIMING AND PLACEMENT IS NOT THE BEST
SO WILL KEEP VALUES JUST AT CLIMO OR BELOW FOR NOW.
GUYER
.FIRE WEATHER...
UPPER HIGH WILL REMAIN CENTERED OVER PORTIONS OF TEXAS AND THE LOWER
MISSISSIPPI VALLEY THROUGH TUESDAY. THE MONSOONAL MOISTURE PLUME
WILL REMAIN CENTERED OVER WESTERN AND CENTRAL NEW MEXICO DURING THIS
PERIOD. WETTING THUNDERSTORMS WILL BE EMBEDDED WITHIN THIS PLUME
WITH HIGHER HUMIDITY.
MODELS SHOWS A GRADUAL CHANGE IN THE MONSOON FLOW WEDNESDAY AND
THURSDAY AS A WEAK TROUGH SWINGS ACROSS THE SOUTHERN AND CENTRAL
ROCKIES. WEDNESDAY COULD BE QUITE DYNAMIC AS FAR AS AN EXPECTED
DRIER TREND ACROSS THE WEST AND WETTING THUNDERSTORMS CENTRAL AND
EASTERN AREAS. MODELS SHOW AN UPTICK IN THE UPPER FLOW SO THIS
SHOULD TRANSLATE INTO A LITTLE STRONGER SURFACE WIND VERSUS WHAT WE
HAVE HAD THE PAST SEVERAL DAYS. MIGHT BE A LITTLE LOW IN THE GRIDDED
WIND FORECAST SO WILL WATCH THE TREND IN THE MODELS. A BACK DOOR
COLD FRONT TIED TO A VIGOROUS LOW PRESSURE AREA SHOULD ADD TO THE
THUNDERSTORM FOCUS ACROSS THE NORTHEAST. IT APPEARS THAT HUMIDITY
VALUES LOWER THE MOST ACROSS THE SOUTHWEST HALF. THURSDAY LOOKS TO
BE DRIER BOTH HUMIDITY AND WETTING THUNDERSTORM WISE. WINDS ALSO
LOOK TO BE LIGHTER ON THURSDAY VERSUS WEDNESDAY.
BOTH THE ECMWF AND GFS WEATHER MODELS SHOW THE UPPER HIGH
REDEVELOPING OVER CENTRAL TEXAS ON FRIDAY. MONSOONAL MOISTURE WOULD
TRY TO FLOW BACK OVER THE AREA. AS OF RIGHT NOW...RESIDUAL OR
LEFTOVER MOISTURE SHOULD FOCUS WETTING THUNDERSTORM DEVELOPMENT OVER
THE NORTH CENTRAL MOUNTAINS AND PORTIONS OF THE NORTHEAST PLAINS.
THE PLUME OF MOISTURE SHOULD REINVIGORATE OVER WESTERN AND CENTRAL
NEW MEXICO DURING THE WEEKEND. HUMIDITY VALUES WOULD TREND UP. A
MONSOON BURST CONCENTRATING SIGNIFICANT MOISTURE AND STORMS WOULD BE
POSSIBLE DURING THIS PERIOD.
WEATHER MODELS TRY TO ELONGATE THE UPPER HIGH OVER PORTIONS OF NEW
MEXICO EARLY NEXT WEEK. RESIDUAL MOISTURE WOULD BE AROUND AND CAUGHT
WITHIN THIS UPPER HIGH ALTHOUGH STORMS WOULD BE MORE IN THE RECYCLE
MODE VERSUS A TRUE MONSOON BURST MODE. THUS THE WETTING RAIN
COVERAGE WOULD GRADUALLY DECLINE. WILL CONTINUE TO MONITOR THIS
TREND.
50
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
216 PM MDT SUN AUG 4 2013
.DISCUSSION...
...INCREASED POTENTIAL FOR LOCALLY HEAVY RAINFALL THROUGH TONIGHT...
RADAR TRENDS INDICATING SCATTERED TO NUMEROUS STORMS ACROSS THE HIGH
TERRAIN OF CENTRAL NM. 19Z LAPS ANALYSIS SHOWS A SIGNIFICANT AMOUNT
OF MOIST INSTABILITY OVER THE AREA WITH 2000-3500J/KG CAPE AND LIFTED
INDICES BTWN -3 AND -6C FROM THE RGV INTO THE NE PLAINS. 700-500MB
STORM MOTION VECTORS ARE NORTH NEAR 5 KTS WHICH IS MUCH SLOWER THAN
YESTERDAY...SO THE HEAVY RAINFALL THREAT IS HIGHER AS WELL. PLACED
MENTION OF LCL HEAVY RAIN IN GRIDS BUT WILL NOT ISSUE A FLASH FLOOD
WATCH. OUTFLOW BOUNDARIES WILL ACTIVATE IN THIS REGIME TO PRODUCE
MORE STORMS FOR VALLEY AREAS LATER IN THE DAY AS SHOWN BY THE RUC
AND HRRR GUIDANCE. A LARGE PRECIP SHIELD IS LIKELY TO MOVE SLOWLY
NORTH OVER CENTRAL NM AS WELL TONIGHT. RAISED POPS CONSIDERABLY FOR
THIS REGION.
MONDAY WILL BE AN ACTIVE DAY AGAIN. THE GFS INDICATES PWAT VALUES
WILL TREND DOWN JUST SLIGHTLY AND THE MAIN AXIS OF INSTABILITY WILL
SHIFT A LITTLE EAST ONTO THE HIGH PLAINS. STORM MOTIONS WILL BE MORE
SOUTHWESTERLY AND SLOW AGAIN. THIS WILL BRING A LITTLE MORE COVERAGE
TO THE EASTERN PLAINS DURING THE EVENING. WESTERN NM WILL STILL SEE
VERY WEAK STORM MOTIONS WITH LCL HEAVY RAINFALL. TUESDAY IS EXPECTED
TO BE ACTIVE AS WELL. AN EASTERLY WAVE NOTED ON WATER VAPOR ALONG
THE WEST CENTRAL MEXICAN COAST WILL SHIFT NORTH AND IMPACT EASTERN
AZ/WESTERN NM. RAISED POPS FOR TUESDAY. STEERING FLOW WILL INCREASE
MORE BUT STILL REMAIN LIGHT ENOUGH FOR HEAVY RAINERS.
DRIER MORE STABLE AIR WILL WORK INTO WESTERN/CENTRAL NM BEHIND THE
UPPER WAVE. STORM COVERAGE WILL DIMINISH CONSIDERABLY FOR THE
WEST. THIS UPPER WAVE WILL BECOME CAUGHT UP IN NORTHWEST FLOW OVER
THE CENTRAL PLAINS STATES AND ENHANCE A SURFACE BACK DOOR FRONTAL
BOUNDARY OVER NORTHEAST NM. THE NAM IS BULLISH WITH THE STRENGTH
OF THIS SURFACE BOUNDARY AND THE COVERAGE OF STORMS. OVERALL THE
PATTERN THROUGH THE REMAINDER OF THE WEEK LOOKS TO LOCK IN A VERY
WELL DEFINED MONSOONAL CIRCULATION OVER CENTRAL/WESTERN NM.
GUYER
&&
.FIRE WEATHER...
UPPER HIGH ANCHORED OVER CENTRAL TEXAS WILL SLOWLY SHIFT TOWARD THE
EAST AND SOUTH THROUGH LATE TUESDAY...BECOMING ELONGATED NEAR THE TX
GULF COAST REGION BY WEDNESDAY MORNING. WELL ADVERTISED UPTICK IN
THUNDERSTORM COVERAGE FOR THIS AFTERNOON HAS PANNED OUT WELL WITH
STORM MOTIONS GENERALLY TOWARD THE NORTH-NORTHEAST AT 15 MPH OR
LESS. OUTFLOW BOUNDARY INTERACTIONS IN THE PRESENCE OF A MUCH MORE
UNSTABLE ENVIRONMENT SHOULD RESULT IN QUITE A BIT MORE THUNDERSTORM
ACTIVITY IN THE VALLEYS BY MID TO LATE AFTERNOON AND INTO THE EVENING
AS COMPARED TO SATURDAY...WITH THE POTENTIAL FOR HEAVY THUNDERSTORM
RAINS INCREASING AND EXPANDING ACROSS THE NORTHEAST. THE UPPER FLOW
REGIME WILL FAVOR LATE NIGHT OR NOCTURNAL SHOWERS FOR AREAS BETWEEN
THE CONTINENTAL DIVIDE AND CENTRAL MOUNTAIN CHAIN WITH THE CENTRAL
VALLEY CORRIDOR ESPECIALLY FAVORED.
WELL-ESTABLISHED MONSOON PLUME ALONG THE WESTERN PERIPHERY OF THE
RIDGE WILL CHANGE VERY LITTLE OVER THE NEXT 24-36 HOURS. LINGERING
CLOUD COVER MONDAY MORNING MAY LIMIT EARLY DAYTIME HEATING AND THUS
TOMORROW/S CROP OF THUNDERSTORMS MAY NOT BE QUITE AS WIDESPREAD AS
TODAY BUT THE PATTERN WILL REMAIN FAVORABLE FOR THE WESTERN
TWO-THIRDS OF THE AREA.
TUESDAY WILL MARK A TRANSITION TO A RELATIVELY FASTER SW TO NE
STEERING FLOW...AND POSSIBLY AN ENHANCED WINDOW OF MOISTURE/DYNAMIC
FORCING ASSOCIATED WITH AN EASTERLY WAVE THAT WILL SLOWLY APPROACH
THE REGION IN THE CLOCKWISE FLOW AROUND THE HIGH. WHILE MODELS SHOW
THIS FEATURE TRACKING NORTH-NORTHWEST WELL TO OUR SOUTHWEST...ITS
REMNANTS SHOULD EVENTUALLY WORK BACK TOWARD THE EAST AND THE FOUR
CORNERS. MEDIUM RANGE GUIDANCE SHOWING SOME NICE CONSISTENCY THUS
FAR AND WE WILL SEE IF THE TREND CONTINUES. OVERALL LOW CONFIDENCE IN
WHAT WILL BECOME OF THIS FEATURE...HOW FAR NORTH IT MAY TRACK BUT
THE MODELS ARE GENERALLY IN DECENT AGREEMENT SHOWING THE WAVE
TRANSLATING EASTWARD OVER SOUTHERN COLORADO AND NORTHERN NEW MEXICO
WED-WED PM. AT THE SAME TIME...A GOOD LOOKING BACKDOOR COLD FRONT
IS INDICATED TO SURGE SOUTHWARD SETTING UP A POTENTIALLY VERY ACTIVE
PATTERN FOR AREAS EAST OF THE CENTRAL MOUNTAIN CHAIN AND ESPECIALLY
THE NORTHEAST. EXTENT OF LOWER LEVEL DRYING ACROSS THE WEST REMAINS
A BIG QUESTION MARK...AS MODELS ARE QUITE AGGRESSIVE IN DRYING DEW
POINTS DURING THE WED/THU PERIOD.
KJ
&&
.AVIATION...
18Z TAF CYCLE
CONSIDERABLY MORE ACTIVE THUNDERSTORM CROP FOR WESTERN AND MUCH OF
NORTHERN NEW MEXICO TODAY...AS COMPARED TO 24-HOURS AGO. THIS
INCLUDES THE ABQ-SANTA FE CORRIDOR. STEERING FLOW GENERALLY S-SW
TO N-NE BUT WEAKER THAN YESTERDAY. AS A RESULT...ANY POTENTIAL
TSRA IMPACTS AT KSAF AND KABQ NOT EXPECTED UNTIL MID- AFTERNOON AT
THE EARLIEST. EARLIER IMPACTS AT KGUP AND KLVS AND HAVE INCLUDED
TEMPO GROUP THERE WHERE CONFIDENCE HIGHEST. FLOW REGIME FAVORABLE
FOR AREAS OF SHRA IN THE VICINITY OF KABQ LATE INTO EVENING IF NOT
PAST MIDNIGHT. ELSEWHERE...AIR MASS LEAST UNSTABLE OVER THE
SOUTHEAST PLAINS AND UNFAVORABLE STEERING FLOW WILL PRECLUDE TSRA
AT KROW. ISOLATED CONVECTION OVER EC/NE NM BUT NOT AS ROBUST AS
YESTERDAY. OUTSIDE OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON/
TONIGHT...VFR CONDITIONS EXPECTED TO PREVAIL.
KJ
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 66 92 65 90 / 40 20 20 20
DULCE........................... 55 86 54 83 / 50 40 30 40
CUBA............................ 56 87 55 84 / 60 40 40 30
GALLUP.......................... 59 84 58 84 / 40 30 30 30
EL MORRO........................ 55 78 53 77 / 50 40 30 40
GRANTS.......................... 58 83 57 82 / 60 30 30 30
QUEMADO......................... 57 81 55 80 / 40 50 30 30
GLENWOOD........................ 61 87 60 85 / 30 30 30 20
CHAMA........................... 52 77 51 74 / 60 50 30 40
LOS ALAMOS...................... 61 82 59 80 / 60 40 30 40
PECOS........................... 59 80 58 77 / 60 40 30 40
CERRO/QUESTA.................... 56 79 55 77 / 60 40 30 40
RED RIVER....................... 49 71 48 69 / 60 50 30 50
ANGEL FIRE...................... 48 75 46 73 / 50 40 30 50
TAOS............................ 56 84 54 82 / 60 30 20 40
MORA............................ 55 79 54 77 / 50 40 30 40
ESPANOLA........................ 62 86 61 84 / 60 30 20 30
SANTA FE........................ 61 83 59 80 / 60 30 20 40
SANTA FE AIRPORT................ 62 87 61 83 / 60 30 20 30
ALBUQUERQUE FOOTHILLS........... 66 89 66 86 / 60 20 20 30
ALBUQUERQUE HEIGHTS............. 67 91 68 88 / 60 20 20 20
ALBUQUERQUE VALLEY.............. 65 92 65 90 / 60 20 20 20
ALBUQUERQUE WEST MESA........... 66 93 66 91 / 60 20 20 20
LOS LUNAS....................... 67 90 65 87 / 60 20 20 20
RIO RANCHO...................... 66 93 66 90 / 60 20 20 20
SOCORRO......................... 67 96 66 91 / 40 20 30 20
SANDIA PARK/CEDAR CREST......... 61 86 60 84 / 60 30 30 30
TIJERAS......................... 62 87 61 85 / 60 30 20 30
MORIARTY/ESTANCIA............... 59 87 58 84 / 60 40 30 30
CLINES CORNERS.................. 61 83 60 81 / 50 50 30 40
GRAN QUIVIRA.................... 61 87 60 83 / 40 30 30 40
CARRIZOZO....................... 65 91 64 86 / 30 30 30 30
RUIDOSO......................... 58 82 57 78 / 30 50 30 60
CAPULIN......................... 57 83 58 82 / 50 40 30 40
RATON........................... 59 88 59 87 / 50 30 30 40
SPRINGER........................ 60 88 59 87 / 40 30 30 30
LAS VEGAS....................... 59 83 58 82 / 50 40 30 40
CLAYTON......................... 67 91 67 92 / 30 30 30 30
ROY............................. 64 88 63 88 / 30 40 30 30
CONCHAS......................... 70 95 69 94 / 20 20 20 30
SANTA ROSA...................... 69 93 68 92 / 20 30 20 30
TUCUMCARI....................... 73 99 72 98 / 10 10 20 20
CLOVIS.......................... 69 95 68 95 / 5 5 10 10
PORTALES........................ 69 95 68 96 / 5 5 10 10
FORT SUMNER..................... 71 95 71 94 / 10 10 20 20
ROSWELL......................... 72 98 72 97 / 5 5 10 20
PICACHO......................... 64 90 66 89 / 20 20 20 30
ELK............................. 61 83 61 82 / 20 30 30 30
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1136 AM MDT SUN AUG 4 2013
.AVIATION...
18Z TAF CYCLE
CONSIDERABLY MORE ACTIVE THUNDERSTORM CROP FOR WESTERN AND MUCH OF
NORTHERN NEW MEXICO TODAY...AS COMPARED TO 24-HOURS AGO. THIS
INCLUDES THE ABQ-SANTA FE CORRIDOR. STEERING FLOW GENERALLY S-SW
TO N-NE BUT WEAKER THAN YESTERDAY. AS A RESULT...ANY POTENTIAL
TSRA IMPACTS AT KSAF AND KABQ NOT EXPECTED UNTIL MID- AFTERNOON AT
THE EARLIEST. EARLIER IMPACTS AT KGUP AND KLVS AND HAVE INCLUDED
TEMPO GROUP THERE WHERE CONFIDENCE HIGHEST. FLOW REGIME FAVORABLE
FOR AREAS OF SHRA IN THE VICINITY OF KABQ LATE INTO EVENING IF NOT
PAST MIDNIGHT. ELSEWHERE...AIR MASS LEAST UNSTABLE OVER THE
SOUTHEAST PLAINS AND UNFAVORABLE STEERING FLOW WILL PRECLUDE TSRA
AT KROW. ISOLATED CONVECTION OVER EC/NE NM BUT NOT AS ROBUST AS
YESTERDAY. OUTSIDE OF SHOWERS AND THUNDERSTORMS THIS
AFTERNOON/TONIGHT...VFR CONDITIONS EXPECTED TO PREVAIL. KJ
&&
.PREV DISCUSSION...1054 AM MDT SUN AUG 4 2013...
16Z LAPS ANALYSIS AND RADAR TRENDS SHOW A LOT MORE ACTIVITY SO FAR
THIS MORNING THAN SATURDAY. STORM MOTIONS WILL TRACK NORTH BTWN 5
AND 10 MPH SO ADDED LOCALLY HEAVY WORDING TO ZONES. A WELL DEFINED
AREA OF MID LEVEL CLOUDINESS AND INSTABILITY MOVING NORTH INTO THE
WESTERN HALF OF LINCOLN AND EASTERN SOCORRO COUNTIES IS SHOWN BY
THE RUC AND HRRR TO EXPAND STORM COVERAGE THIS AFTERNOON. INCREASED
POPS TO HIGH CHANCE/LIKELY FOR MUCH OF THE CENTRAL MOUNTAIN CHAIN
EASTWARD ALONG THE EAST SLOPES. ALSO RAISED CHANCES FOR ABQ METRO
AREA GIVEN CONVECTION ALREADY DEVELOPING TO OUR SOUTH.
GUYER
.PREV DISCUSSION...324 AM MDT SUN AUG 4 2013...
SUBSIDENCE INVERSION JUST ABOVE 700MB PROGGED TO GRADUALLY DISSIPATE
EARLY THIS MORNING AS OUTFLOWS FROM STORMS OVER NE NM CONTINUES TO
PUSH SOUTHWESTWARD THROUGH THE CANYONS OF THE CENTRAL MTNS...USHERING
IN SLIGHTLY COOLER MID LEVEL AIR. NAMBUFR DATA ALSO PROGGING A
MUCH BETTER INSTABILITY PROFILE FOR THIS AFTERNOON AS SURFACE
TEMPERATURES WARM TO A DEGREE OR TWO ABOVE SATURDAY HIGHS AND 500MB
TEMPS COOL BY ABOUT 1.5C. SCATTERED THUNDERSTORMS WILL DEVELOP OVER
THE WESTERN AND NORTHERN MOUNTAINS DURING THE LATE MORNING/EARLY
AFTERNOON...THEN MOVE TO THE NORTHEAST BTWN 10-20MPH OVER THE
CENTRAL AND WEST-CENTRAL PORTIONS OF THE STATE. STORMS WILL MOVE
EASTWARD BTWN 5-10 MPH OVER THE NORTH AS THE FLOW ALOFT CURLS
CLOCKWISE AROUND THE UPPER HIGH CENTER OVER WEST TX.
AS THE UPPER HIGH CENTER INCHES EASTWARD MONDAY...500MB TEMPERATURES
COOL ANOTHER DEGREE C OR SO...MAKING FOR A SLIGHTLY MORE UNSTABLE
AIRMASS. ELY WAVE IS FORECAST BY ALL NWP MODELS TO ROUND THE BASE
OF THE UPPER HIGH AND HEAD NORTHWARD INTO AZ TUESDAY FORENOON.
DEEP SUBTROPICAL MOISTURE GETS PULLED UP IN THE SLY FLOW AHEAD OF
THE WAVE OVER NM TUESDAY AFTERNOON. BOTH NAM AND GFS DEEPEN THE
WAVE OVER SE COLORADO TUESDAY NIGHT...CLOSING IT OFF NEAR THE FOUR
CORNERS WEDNESDAY. THIS FEATURE SHOULD ACT TO HELP GET SCATTERED
TO NUMEROUS STORMS TO FIRE OVER CENTRAL AND NORTHERN NM WEDNESDAY
AS COLDER AIR ALOFT ASSOCIATED WITH THE UPPER LOW GRADUALLY INVADE
THE AREA FROM THE NORTHWEST.
UPPER LEVEL RIDGE PUMPS UP RAPIDLY OVER THE REGION THURSDAY...MAKING
FOR A DOWN DAY FOR CONVECTIVE ACTIVITY FORECAST AREA-WIDE. BOTH
GFS AND ECMWF BRING BACK THE MONSOONAL PLUME IN A HURRY THURSDAY
NIGHT AND CONTINUE IT THROUGH NEXT WEEKEND.
33
.FIRE WEATHER...
WETTING RAINS WILL FAVOR WESTERN PORTIONS OF THE FORECAST AREA TODAY
UNDER THE EASTERN-MOST EXTENT OF THE MONSOONAL MOISTURE PLUME. THE
SANGRE DE CRISTO MOUNTAINS...NORTHEAST HIGHLANDS AND NORTHEAST
PLAINS WILL LIKELY BENEFIT FROM WETTING RAINS AS WELL. TEMPERATURES
WILL GENERALLY BE NEAR NORMAL WEST AND ABOVE NORMAL EAST. VENT RATES
ARE FORECAST TO BE FAIR TO POOR CENTRAL AND WEST...BUT HIGHLY
DEPENDENT ON CLOUDS AND POTENTIAL RAIN-COOLING LIMITING SURFACE
HEATING.
MORE OF THE SAME ON MONDAY AS THE UPPER HIGH CENTER REMAINS TO THE
EAST OVER CENTRAL TEXAS. TUESDAY WILL BE A TRANSITION DAY AS
PRESSURE HEIGHTS DECREASE WITH AN EASTERLY WAVE MOVING AROUND THE
UPPER HIGH CIRCULATION OVER ARIZONA AND INTO THE FOUR CORNERS AREA.
THIS WILL HELP TO DESTABILIZE THE ATMOSPHERE AND SHOULD LEAD TO AN
UPTICK IN WETTING RAINS FOR MUCH OF THE AREA. A BACKDOOR FRONT WILL
GET INTO THE MIX TUESDAY NIGHT THROUGH WEDNESDAY ACROSS THE EASTERN
PLAINS AND COMBINE WITH THE EASTERLY WAVE TO BRING WETTING RAINS TO
MUCH OF THE EAST...ESPECIALLY NORTHEAST. TEMPERATURES WILL TREND
DOWN DURING THIS PERIOD ACROSS THE EAST AND HUMIDITIES WILL TREND
UP. A MORE TRADITIONAL MONSOON SYNOPTIC WEATHER PATTERN LOOKS TO
DEVELOP BY THE END OF THE WORK WEEK...WITH THE UPPER HIGH NEAR THE
ARKLATEX AND A WEST COAST TROUGH ALLOWING FOR DEEP SOUTHERLIES
ACROSS NEW MEXICO. NO END IN SIGHT TO DAILY ROUNDS OF WETTING
SHOWERS AND STORMS.
11
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1054 AM MDT SUN AUG 4 2013
.UPDATE...
16Z LAPS ANALYSIS AND RADAR TRENDS SHOW A LOT MORE ACTIVITY SO FAR
THIS MORNING THAN SATURDAY. STORM MOTIONS WILL TRACK NORTH BTWN 5
AND 10 MPH SO ADDED LOCALLY HEAVY WORDING TO ZONES. A WELL DEFINED
AREA OF MID LEVEL CLOUDINESS AND INSTABILITY MOVING NORTH INTO THE
WESTERN HALF OF LINCOLN AND EASTERN SOCORRO COUNTIES IS SHOWN BY
THE RUC AND HRRR TO EXPAND STORM COVERAGE THIS AFTERNOON. INCREASED
POPS TO HIGH CHANCE/LIKELY FOR MUCH OF THE CENTRAL MOUNTAIN CHAIN
EASTWARD ALONG THE EAST SLOPES. ALSO RAISED CHANCES FOR ABQ METRO
AREA GIVEN CONVECTION ALREADY DEVELOPING TO OUR SOUTH.
GUYER
&&
.PREV DISCUSSION...532 AM MDT SUN AUG 4 2013...
.AVIATION...
12Z TAF CYCLE
SHORT-LIVED MVFR CIGS MAY DEVELOP AT KLVS EARLY THIS MORNING...
OTHERWISE VFR CONDITIONS TO PREVAIL AT TERMINALS OUTSIDE OF
SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON/EVENING.
MVFR...AND EVEN SHORT-LIVED IFR CONDITIONS LIKELY IN/NEAR STORMS
TODAY. TERMINALS MOST LIKELY TO BE IMPACTED BY TSRA TODAY INCLUDE
KGUP...KSAF AND KLVS.
11
.PREV DISCUSSION...324 AM MDT SUN AUG 4 2013...
SUBSIDENCE INVERSION JUST ABOVE 700MB PROGGED TO GRADUALLY DISSIPATE
EARLY THIS MORNING AS OUTFLOWS FROM STORMS OVER NE NM CONTINUES TO
PUSH SOUTHWESTWARD THROUGH THE CANYONS OF THE CENTRAL MTNS...USHERING
IN SLIGHTLY COOLER MID LEVEL AIR. NAMBUFR DATA ALSO PROGGING A
MUCH BETTER INSTABILITY PROFILE FOR THIS AFTERNOON AS SURFACE
TEMPERATURES WARM TO A DEGREE OR TWO ABOVE SATURDAY HIGHS AND 500MB
TEMPS COOL BY ABOUT 1.5C. SCATTERED THUNDERSTORMS WILL DEVELOP OVER
THE WESTERN AND NORTHERN MOUNTAINS DURING THE LATE MORNING/EARLY
AFTERNOON...THEN MOVE TO THE NORTHEAST BTWN 10-20MPH OVER THE
CENTRAL AND WEST-CENTRAL PORTIONS OF THE STATE. STORMS WILL MOVE
EASTWARD BTWN 5-10 MPH OVER THE NORTH AS THE FLOW ALOFT CURLS
CLOCKWISE AROUND THE UPPER HIGH CENTER OVER WEST TX.
AS THE UPPER HIGH CENTER INCHES EASTWARD MONDAY...500MB TEMPERATURES
COOL ANOTHER DEGREE C OR SO...MAKING FOR A SLIGHTLY MORE UNSTABLE
AIRMASS. ELY WAVE IS FORECAST BY ALL NWP MODELS TO ROUND THE BASE
OF THE UPPER HIGH AND HEAD NORTHWARD INTO AZ TUESDAY FORENOON.
DEEP SUBTROPICAL MOISTURE GETS PULLED UP IN THE SLY FLOW AHEAD OF
THE WAVE OVER NM TUESDAY AFTERNOON. BOTH NAM AND GFS DEEPEN THE
WAVE OVER SE COLORADO TUESDAY NIGHT...CLOSING IT OFF NEAR THE FOUR
CORNERS WEDNESDAY. THIS FEATURE SHOULD ACT TO HELP GET SCATTERED
TO NUMEROUS STORMS TO FIRE OVER CENTRAL AND NORTHERN NM WEDNESDAY
AS COLDER AIR ALOFT ASSOCIATED WITH THE UPPER LOW GRADUALLY INVADE
THE AREA FROM THE NORTHWEST.
UPPER LEVEL RIDGE PUMPS UP RAPIDLY OVER THE REGION THURSDAY...MAKING
FOR A DOWN DAY FOR CONVECTIVE ACTIVITY FORECAST AREA-WIDE. BOTH
GFS AND ECMWF BRING BACK THE MONSOONAL PLUME IN A HURRY THURSDAY
NIGHT AND CONTINUE IT THROUGH NEXT WEEKEND.
33
.FIRE WEATHER...
WETTING RAINS WILL FAVOR WESTERN PORTIONS OF THE FORECAST AREA TODAY
UNDER THE EASTERN-MOST EXTENT OF THE MONSOONAL MOISTURE PLUME. THE
SANGRE DE CRISTO MOUNTAINS...NORTHEAST HIGHLANDS AND NORTHEAST
PLAINS WILL LIKELY BENEFIT FROM WETTING RAINS AS WELL. TEMPERATURES
WILL GENERALLY BE NEAR NORMAL WEST AND ABOVE NORMAL EAST. VENT RATES
ARE FORECAST TO BE FAIR TO POOR CENTRAL AND WEST...BUT HIGHLY
DEPENDENT ON CLOUDS AND POTENTIAL RAIN-COOLING LIMITING SURFACE
HEATING.
MORE OF THE SAME ON MONDAY AS THE UPPER HIGH CENTER REMAINS TO THE
EAST OVER CENTRAL TEXAS. TUESDAY WILL BE A TRANSITION DAY AS
PRESSURE HEIGHTS DECREASE WITH AN EASTERLY WAVE MOVING AROUND THE
UPPER HIGH CIRCULATION OVER ARIZONA AND INTO THE FOUR CORNERS AREA.
THIS WILL HELP TO DESTABILIZE THE ATMOSPHERE AND SHOULD LEAD TO AN
UPTICK IN WETTING RAINS FOR MUCH OF THE AREA. A BACKDOOR FRONT WILL
GET INTO THE MIX TUESDAY NIGHT THROUGH WEDNESDAY ACROSS THE EASTERN
PLAINS AND COMBINE WITH THE EASTERLY WAVE TO BRING WETTING RAINS TO
MUCH OF THE EAST...ESPECIALLY NORTHEAST. TEMPERATURES WILL TREND
DOWN DURING THIS PERIOD ACROSS THE EAST AND HUMIDITIES WILL TREND
UP. A MORE TRADITIONAL MONSOON SYNOPTIC WEATHER PATTERN LOOKS TO
DEVELOP BY THE END OF THE WORK WEEK...WITH THE UPPER HIGH NEAR THE
ARKLATEX AND A WEST COAST TROUGH ALLOWING FOR DEEP SOUTHERLIES
ACROSS NEW MEXICO. NO END IN SIGHT TO DAILY ROUNDS OF WETTING
SHOWERS AND STORMS.
11
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
735 PM EDT MON AUG 5 2013
.SYNOPSIS...
HIGH PRESSURE OVER NEW YORK WILL MOVE OFF THE EAST COAST TONIGHT.
AN INCREASINGLY MOIST SOUTHERLY FLOW WILL DEVELOP ON TUESDAY AND
CONTINUE INTO WEDNESDAY AHEAD OF A COLD FRONT. SCATTERED SHOWERS
WILL BE POSSIBLE ON TUESDAY OVER PORTIONS OF NORTHEAST
PENNSYLVANIA AND CENTRAL NEW YORK...WITH SHOWERS AND THUNDERSTORMS
BECOMING MORE LIKELY ON WEDNESDAY AND WEDNESDAY NIGHT AS THE COLD
FRONT APPROACHES. LINGERING SHOWERS WILL BE POSSIBLE ACROSS
NORTHEAST PENNSYLVANIA INTO THURSDAY AFTERNOON NEAR THE DEPARTING
FRONT.
&&
.NEAR TERM /THROUGH TUESDAY/...
SFC HI PRES CNTRD OVER NY/PA THIS AFTN WILL DRIFT EWD OFF THE EAST
CST TNGT. DIURNAL CU XPCTD TO DSPT LATER THIS AFTN...WITH SOME MID
AND HI LVL CLDS WORKING INTO THE RGN TNGT. RUC LOOKS OVERDONE WITH
RETURNING LOW LVL MSTR LATER TNGT...AND XPCT ANY CONVECTION ASSCD
WITH UPSTREAM S/WV`S OVER THE GTLAKES TO DSPT/WEAKEN AS THEY MOV
EWD TWDS THE RGN.
K INDICES ON TUE AFTN SUGGEST BEST CHC FOR SCT CONVECTION ACRS
PORTIONS OF THE WYOMING VLY INTO THE CNTRL SRN TIER AND FINGER
LAKES WHERE K`S >32 AND BL LI`S ARND -1 TO -2. GFS ALSO SUGGESTS
BEST CHC FOR SCT ACTIVITY WILL BE ACRS WRN ZONES ON TUE BASED ON
LOW LVL CONVERGENCE AND INSTABILTY FIELDS. FOR NOW JUST INDICATED
THE CHC FOR -SHRA ON TUE ACRS THESE AREAS. CLD FIELDS AVERAGED OUT
TO MOSTLY CLDY...BUT WE`LL LIKELY SEE A DECENT AMT OF SUNSHINE
THROUGH THE MID/UPR DECK. MAXES GNRLY M/U70S.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
CONFIDENCE FACTOR DECREASES IN THE SHORT TERM...AS DETERMINISTIC
MDLS STILL SHOW DIFFS IN TIMING OF FNT AND POTNL CONVECTIVE
SYSTEMS. LOW LVL MSTR WILL INCRS ON SRLY FLOW...WITH LOW CLDS PSBL
ACRS THE SRN TIER AND NE PA BY WED MRNG. FOR NOW RETAINED SLGT
CHC/LOW CHC POPS ON TUE NGT...INCRSNG TO LIKELY BY WED NGT WITH
APRCH OF THE CDFNT. BY 12Z THU...IT APPEARS THAT THE FNT WILL JUST
BE ENTERING THE FAR WRN/NW ZONES...GETTING INTO THE SRN CATSKILLS
AND NE PA BY THU EVNG. SOME IMPRVMNT IS LIKELY IN THE AFTN ACRS
THE FINGER LAKES...CNTRL SRN TIER AND SRN TUG ON THU AFTN...WITH
CHC POPS ACRS SE ZONES CLOSER TO THE FNT.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
CHGS MADE TO EXTNDD PORTION OF THE FCST BASED ON 12Z GUIDANCE
FILTERING IN. 12Z GFS BRINGS BNDRY THRU THURSDAY AND THEN IT APPEARS
TO GET HUNG UP ACRS THE AREA. THIS WL SET THE STAGE FOR SFC LOW TO
RIDE UP ALONG THE FRONT PER GFS AND LATEST CMC ON FRIDAY. GFS IS
FURTHER NORTH THAN CMC AT THIS POINT RIDING IT NORTH ALONG THE AXIS
OF THE GREAT LKS, WHEREAS CMC MVS IT ACRS NRN TIER OF PA INTO HUDSON
VLY BY 06Z SATURDAY. 00Z EURO ALSO HINTING AT A WK LOW TREKKING ACRS
THE AREA ON FRIDAY THO NOT AS STRONG AS GFS OR CMC. BASED ON LATEST
TRENDS, HV BUMPED POPS TO BTWN 40-50% FOR FRIDAY AND DROPPED AFTN
MAXES INTO THE 70S.
FROPA LOOKS TO FINALLY OCCUR FRIDAY NIGHT AS SFC LOW HEADS INTO
CANADIAN MARITIMES WITH DRYING HIPRES BUILDING IN AND POPS DWINDLING
BY 12Z SATURDAY. NW FLOW WL FILTER IN COOL ADVECTION WITH H8 TEMPS
DROPPING TO NR +10C FOR SATURDAY AFTN. CAA CONTS FOR SUNDAY AS NW
FLOW RMNS OVR THE AREA THUS EXPECTING TEMPS TO BE COOLER ON SUNDAY
WITH OVERALL TEMPS THRU THE PD RUNNING BLO NORMAL.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
730 PM UPDATE...
HIGH PRESSURE AND VFR CONDITIONS ACROSS THE AREA TTONIGHT. SOME
MID AND HIGH CLOUDS NOW. KELM HAS THE POTENTIAL FOR SOME MVFR
VSBY VALLEY FOG LATE TONIGHT. BOUNDARY LAYER WINDS PICK UP TOWARDS
12Z SO BETWEEN THE CLOUDS THIS EVENING AND THE MIXING WINDS LATE
TONIGHT DO NOT THINK IT WILL FALL TO IFR.
DURING THE DAY TUESDAY MORE CU WILL FORM WITH SCATTERED SHOWERS
MOVING IN FROM THE WEST IN THE AFTN. DO NOT EXPECT ANYTHING OTHER
THAN VFR. BETTER CHANCES OF SHOWERS TUE NGT INTO WED.
WINDS LESS THAN 5 KTS TONIGHT...MAINLY OUT OF THE EAST. TUESDAY S
WINDS 5 TO 10 KTS.
OUTLOOK...
TUE NIGHT...CHC MVFR SHWRS.
WED/WED NIGHT...MVFR SHWRS/TSRA.
THU...MVFR IN SHRA AND TSRA IMPROVING TO VFR LATE.
FRI...VFR BUT MVFR IN SHRA/TSRA.
SAT...BECOMING VFR UNDER HIGH PRESSURE
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...PVN
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
203 PM EDT SUN AUG 4 2013
.SYNOPSIS...
A COOLER NORTHWEST FLOW WILL DEVELOP TODAY...ALONG WITH SCATTERED
LIGHT SHOWERS THROUGH EARLY AFTERNOON...MAINLY OVER CENTRAL NEW
YORK. A HIGH PRESSURE SYSTEM WILL THEN BUILD IN TONIGHT THROUGH
MONDAY...WITH MAINLY CLEAR SKIES. VERY COOL TEMPERATURES
OVERNIGHT...WILL MODERATE BACK INTO THE 70S MONDAY AFTERNOON.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
930 AM...LAKE EFFECT CLDS ARE NOW WELL ENTRENCHED IN THE AREA THIS
MRNG. NAM TRIES TO DRY US OUT LTR IN THE AFTN WHILE THE HRRR KEEPS
THE CLDS AND SPRINKLES THRU THE DAY. LEAN TWRDS THE HRRR SOLN AS
IT/S NEVER SMART TO UNDERESTIMATE THE ABILITY OF UPSTATE NY TO
GENERATE CLDS IN A COOL NW FLOW. HAVE LWRD AFTN HI/S A BIT AND
INCRSD CLDS AND PCPN CHANCE.
415 AM UPDATE... WATER VAPOR IMAGERY SHOWS AN UPR LVL TROUGH IN
THE PROCESS OF DEEPENING ACRS THE UPR LKS RGN...SERN CANADA...AND
THE NERN CONUS THIS MRNG. AS THIS EVOLUTION CONTS TDY...A NWLY
FLOW REGIME AND LOW-LVL CAA WILL PREVAIL. THE LATEST MESO`S
ALREADY SHOW 850 MB TEMPS DOWN TO ABT 7C OVER LK ONT...WITH
READINGS PROGGED TO DROP TO 5-6C BY ARND 18Z. GIVEN LK ONT WATER
TEMPS OF 22-24C...ALG WITH THE PRESENCE OF LOW-LVL MOISTURE
TRAPPED UNDER A SUBSIDENCE INVERSION ALOFT...SCTD LK EFF -SHRA
WILL PREVAIL THROUGH MIDDAY-EARLY AFTN. A 290-300 VECTOR FAVORS A
CORRIDOR THROUGH ONONDAGA/SRN CAYUGA/NRN CORTLAND/ONEIDA/MADISON/CHENANGO/
OTSEGO/NRN DELAWARE CNTYS. THESE SHWRS SHOULD DIMINISH BY
18-21Z...AS THE COLUMN BEGINS TO DRY OUT BY THIS TIME.
FARTHER S AND W...ACRS THE TWIN TIERS...THE WYO/LACK VLYS...AND
THE POCONOS...PTLY TO MOSTLY SUNNY SKIES WILL PREVAIL.
AS ALLUDED TO ABV...MAX TEMPS WILL BE COOLER TDY (HIGHS RANGING
FROM THE UPR 60S-MID 70S).
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
430 AM UPDATE... GENERALLY QUIET WX FORESEEN THIS PD...AS RIDGING
BOTH SFC AND ALOFT BUILD IN TNT-MON...GRADUALLY MOVING OFF THE
COAST ON TUE.
THE COMBO OF CLEARING SKIES AND A COOL AMS WILL LEAD TO MIN TEMPS
DOWN TO THE MID 40S IN NORMALLY CHILLIER VLYS LTR TNT/EARLY MON...WITH
PATCHY VLY FOG PSBL ACRS THE TWIN TIERS. AS THE AMS MODIFIES DURG
THE DAY MON...PLENTY OF SUNSHINE SHOULD HELP AFTN TEMPS RECOVER
INTO THE 70S (2-4 DEGS HIGHER THAN ON SUN MOST AREAS).
BY TUE...A RETURN SRLY FLOW DVLPS...LEADING TO WARM AND MOIST
ADVECTION. WE MAY SEE A FEW -SHRA DVLP...BUT MOST OF THESE WILL
LIKELY RESIDE ACRS OUR WRN/SRN ZNS...CLOSER TO PASSING S/WV
ENERGY...AND ALSO AN APPROACHING WARM FRNTL BNDRY. FOR NOW...WE`LL
SIMPLY CALL FOR ISOLD-SCTD SHWRS THESE AREAS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
GDNC COMING INTO BETTER AGREEMENT WITH MID TO LATE WEEK FROPA
ASSCD WITH S/WV ROTATING ARND A CLOSED LOW OVER CNTRL CANADA. SOME
QUESTION ON THE XTNT OF SRN STREAM INFLUENCES ON THIS SYSTEM.
OVERALL...XPCT CDFNT TO PASS MOST OF THE RGN ON THU...ALTHO SOME
LINGERING PCPN PSBL FAR SE ZONES ON FRI CLOSER TO THE RETREATING FNTL
BNDRY. OTRW...HIGH PRES BUILDS INTO THE AREA LATE WEEK INTO NXT
WEEKEND. 2NDRY CDFNT HINTED AT FOR NXT WEEKEND (SAT) BUT IT LOOKS
FAIRLY DRY AT THIS POINT. SO AFTER THURSDAY`S FROPA...GNRLY DRY WX
AND TEMPS AVERAGING NEAR OR A FEW DEG BLO NORMAL. WPC GUIDANCE
LOOKED GOOD AND UTILIZED WITH LTL MODIFICATION.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
2 PM EDT UPDATE... GENERALLY VFR WITH AN AREA OF SCATTERED
SHOWERS WITH MVFR CIGS 020-030 AND VSBY GENERALLY 5SM IN -SHRA IS
MOVING ACROSS THE CATSKILLS..SOUTHERN TIER OF NY AND NORTHERN TIER
OF PA AT 18Z. THIS AREA WILL CONTINUE MOVING SOUTHEAST WITH
CLEARING BEHIND IT JUST LEAVING SOME SCATTER VFR STRATOCU 030-050
BASES WHICH WILL DISSIPATE FURTHER WITH SUNSET.
WINDS ARE FROM THE NW AT 10-15KT WITH SOME GUSTS 20KT. WINDS WILL
ALSO SETTLE DOWN NEAR SUNSET. STRONG RADIATIONAL COOLING TONIGHT
WILL LEAD TO LIGHT WINDS IN THE VALLEYS AND IFR FOG OVER THE
RIVERS AND LAKES FROM 09 TO 12Z. EXPECTING FOG TO BE SHALLOW AND
JUST LAST A FEW HOURS DUE TO BOUNDARY LAYER WINDS AND DRY AIR
MOVING DOWN FROM THE NORTHWEST.
MONDAY WILL BE VFR WITH FEW CLOUDS.
OUTLOOK...
MON NIGHT...VFR. LOCAL IFR VALLEY FOG.
TUE...GENERALLY VFR. CHC MVFR SHWRS.
TUE NIGHT - WED NIGHT...MVFR CIGS SHWRS/TSRA.
THU...MVFR IN SHRA AND TSRA IMPROVING TO VFR LATE.
FRI...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...MLJ
SHORT TERM...DGM/MLJ
LONG TERM...
AVIATION...BMW
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
135 PM EDT SUN AUG 4 2013
.SYNOPSIS...
A DEEP TROUGH OF LOW PRESSURE CONTINUES ACROSS OUR REGION TODAY WITH
ADDITIONAL SHOWERS WITH EMBEDDED THUNDERSTORMS POSSIBLE.
TEMPERATURES WILL BE 5 TO 10 DEGREES BELOW NORMAL WITH HIGHS MAINLY
IN THE 60S TO NEAR 70. HIGH PRESSURE LOCATED OVER THE CENTRAL GREAT
LAKES WILL SHIFT INTO THE REGION ON MONDAY...WITH CLEARING SKIES AND
COOL TEMPERATURES. A WARMING TREND IS EXPECTED BY THE MIDDLE OF THIS
UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1030 AM EDT SUNDAY...FORECAST APPEARS ON TRACK AND JUST SOME
MINOR EDITS NECESSARY. SCATTERED SHOWERS BEGINNING TO APPEAR AS
SHORT WAVE TROF SWINGS THROUGH. BEST CHANCE FOR SHOWERS WILL BE
NORTHERN VERMONT...THOUGH MOST AREAS WILL SEE SOME SCATTERED
ACTIVITY. BEST CHANCE FOR A T-STORM WILL BE CENTRAL/SOUTHERN
VERMONT TODAY WHERE SUNSHINE APPEARED THIS MORNING AND BEST
INSTABILITY EXISTS. INCREASED TEMPS SLIGHTLY ACROSS THE SOUTHERN
VERMONT TO ACCOUNT FOR ADDITIONAL SUNSHINE...OTHERWISE MINOR
CHANGES.
ONCE AGAIN FCST FOCUS WL BE AREAL COVERAGE/INTENSITY OF
SHOWERS/STORMS TODAY. WATER VAPOR SHOWS DEEP MID/UPPER LVL TROF
ACRS THE NE CONUS...WITH TWO ADDITIONAL S/W`S EXPECTED TO IMPACT
OUR CWA TODAY. FIRST S/W IS LOCATED OVER JUST NORTH OF THE EASTERN
GREAT LAKES...AND WL BE ACRS OUR WESTERN ZNS BTWN 12-15Z
TODAY...MEANWHILE STRONG ENERGY BTWN HUDSON BAY AND NORTHERN GREAT
LAKES WL APPROACH OUR CWA BY 18Z TODAY. THIS PIECE OF ENERGY
DIVING ALONG THE SOUTHERN PERIPHERY OF TROF WL HELP DEVELOP A
CLOSED 5H/7H CIRCULATION OVER SOUTHERN CANADA BY 00Z MONDAY. THIS
CYCLONIC UPSLOPE FLW...ALONG WITH LLVL CAA...AND LEFTOVER 1000 TO
700 MOISTURE WL HELP IN THE DEVELOPMENT OF ADDITIONAL UPSLOPE
SHOWERS THIS EVENING. FOR TODAY...WL CONT TO MENTION LIKELY POPS
WITH GREATEST CHCS ACRS THE NORTHERN/CENTRAL ZNS...WHERE 850 TO
500MB RH IS THE DEEPEST. IN ADDITION...BEST PVA ASSOCIATED WITH 5H
VORT AND NOSE OF 25H JET IS ACRS THIS REGION. LATEST RAP SOUNDINGS
CONT TO SUPPORT SOME SFC HEATING RESULTING IN CAPE VALUES BTWN 800
AND 1200 J/KG...AND LIS AROUND -2C...FROM DEVELOPING COLD POOL
ALOFT. THIS INSTABILITY SHOULD PROMOTE STRONG ENOUGH UPDRAFTS TO
SUPPORT MENTION OF THUNDER...ESPECIALLY MTNS AND NORTHERN CWA. THE
COMBINATION OF LOW WET BULB ZERO HEIGHTS ASSOCIATED WITH COLD
THERMAL PROFILES...SOME SMALL HAIL WL BE POSSIBLE...IN ADDITION TO
LOCALIZED WIND GUSTS TO 30 MPH. THE LACK OF INSTABILITY WL KEEP
STORMS BLW SVR LIMITS THIS AFTN AND LIMITED DEEP MOISTURE WL LIMIT
AREAL COVERAGE. WL MENTION CHCS IN HWO...BUT NOT ZONES ATTM. CWMW
SOUNDING SHOWS 1000 TO 850MB TEMPS BTWN 1 AND 3C COOLER THAN 24HR
AGO...SUPPORTING HIGHS ONLY IN THE 60S MTNS TO NEAR 70F VALLEYS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
AS OF 415 AM EDT SUNDAY...LARGE SCALE SYNOPTIC FORCING FROM
POTENT 5H VORT WL TRANSITION TO MESOSCALE UPSLOPE LIFT AS CYCLONIC
NW FLW CONTS ACRS OUR REGION TONIGHT. EXPECT AREAL COVERAGE/INTENSITY OF
PRECIP TO QUICKLY DISSIPATE BY 00Z THIS EVENING...WITH
PRECIP CONFINED ALONG THE UPSLOPE REGIONS OF THE NORTHERN DACKS AND
CENTRAL/GREEN MTNS. UPSLOPE PROCEDURE SHOWS GOOD 1000 TO 700MB
RH...FAVORABLE SFC TO 700MB FLW OF 20 TO 30 KNOTS...AND ASSOCIATED
ENHANCED UVVS ACRS THE WESTERN SLOPES. WL MENTION LIKELY POPS THRU
03Z ACRS THE MTNS...WITH SCHC/CHC POPS ELSEWHERE...AFT 03Z DEEP
LAYER MOISTURE QUICKLY DECREASES AS SUBSIDENCE DEVELOPS. THIS WL
RESULT IN CLRING SKIES IN MOST LOCATIONS BY MORNING...EXCEPT
NORTHERN VT. LLVL CAA RESULTS IN PROGGED 85H TEMPS BTWN 2-4C BY
12Z MONDAY...WITH GOOD BL MIXING. THIS WL SUPPORT ADVECTION TYPE
COOLING WITH LOWS RANGING FROM THE U30S SLK TO NEAR 50F CPV. IF
WINDS DECOUPLE AT SLK...COULD SEE TEMPS DROP INTO THE MID 30S BY
12Z MONDAY.
MONDAY AND TUESDAY...SFC HIGH PRES BUILDING ACRS OUR CWA WL RESULT
IN DRY CONDITIONS AND BLW NORMAL TEMPS. THERMAL SOUNDINGS SUGGEST
MORE OF A FALL LIKE TEMP PROFILE ON MONDAY. PROGGED 85H TEMPS BTWN
4-6C...WITH MOSTLY SUNNY SKIES SUPPORT HIGHS 60S TO NEAR 70 MOST
LOCATIONS. A CHILLY NIGHT IS EXPECTED ON MONDAY NIGHT/TUES MORNING
WITH LOWS RANGING FROM M30S SLK/LAKE PLACID/NEK TO M/U 40S CPV...AND
MID 50S NEAR THE LAKE. TUESDAY...WEAK LLVL WAA DEVELOPS WITH MAINLY
CLR SKIES AND TEMPS IN THE 70S. INTERESTING TO SEE THE GOOD MIXING
ON MONDAY AFTN...AND HOW THE SFC DWPTS DROP INTO THE M/U 30S...VERY
DRY AIR IS PROGGED TO MIX DOWN....RESULTING IN LOW RH VALUES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 415 AM EDT SUNDAY...LARGE UPPER TROUGH TAKES SHAPE OVER CENTRAL
CANADA AND THE UPPER MIDWEST TUESDAY NIGHT INTO WEDNESDAY
MORNING. THIS WILL HELP TO BACK THE UPPER FLOW TO THE WEST AND
SOUTHWEST ON WEDNESDAY. THIS WILL ALLOW 850/925 MILLIBAR
TEMPERATURES TO RISE AND LOOKING AT HIGH TEMPERATURES RIGHT AROUND
SEASONAL NORMALS WEDNESDAY. CLOUDS WILL ALSO BE ON THE INCREASE
AND THERE COULD BE SOME AFTERNOON THUNDERSTORMS...BUT IT APPEARS
BEST DYNAMIC SUPPORT/SURFACE COLD FRONT DO NOT MOVE INTO THE AREA
UNTIL WEDNESDAY NIGHT AND THURSDAY. GOING FORECAST HAS THIS IDEA
COVERED WELL AND HAVE CONTINUED THIS THINKING IN THE GRIDS.
FORCING/COLD FRONT MOVE EAST OF THE AREA THURSDAY NIGHT FOR A
DRYING TREND AND PRONOUNCED WESTERLY FLOW ALOFT DEVELOPS OVER THE
AREA ON FRIDAY. LOW LEVEL THERMAL PROFILE SHOWS WARMEST READINGS
OF THE WEEK MOVE INTO THE AREA ON FRIDAY. THIS WILL PRODUCE HIGH
TEMPERATURES AT OR SLIGHTLY ABOVE SEASONAL NORMALS. AN UPPER LEVEL
DISTURBANCE WILL APPROACH THE AREA LATER ON SATURDAY... BUT BEST
FORCING LOOKS TO STAY UP IN CANADA...THUS GOING FORECAST OF A
SLIGHT CHANCE OF SHOWERS LOOKS GOOD.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
THROUGH 18Z MONDAY...SCT-BKN VFR CLOUDS WILL PERSIST THROUGH THE
REMAINDER OF THE DAYLIGHT HOURS AND INTO THE EARLY EVENING ALONG
WITH SCATTERED RAIN SHOWERS WITH POSSIBLY A FEW LIGHTNING STRIKES
AND SOME SMALL HAIL. SKIES TREND TOWARDS CLEAR AFTER 02Z AS HIGH
PRESSURE BUILDS INTO THE AREA...WITH GUSTY WEST/NORTHWEST WINDS
ABATING. CLEARING SKIES OVERNIGHT COULD LEAD TO SOME FOG DEVELOPMENT
AFTER 05Z...ESPECIALLY AT KSLK BUT BOUNDARY LAYER WINDS MAY STAY
STRONG ENOUGH TO INHIBIT IT. NOT OVERLY CONFIDENT AT THIS TIME SO
HAVE OFFERED SOME 3SM BR FOR NOW AND WILL ALLOW THE NEXT SHIFT TO
REASSESS. AFTER 12Z MONDAY...CLEAR SKIES WILL GIVE WAY TO FEW-SCT
FAIR WEATHER CLOUDS...WITH CONDITIONS REMAINING VFR ALONG WITH NW
WINDS OF 5-10 KNOTS.
OUTLOOK 18Z MONDAY THROUGH FRIDAY...
18Z MONDAY THROUGH 12Z WEDNESDAY...VFR UNDER SURFACE HIGH PRESSURE.
12Z WEDNESDAY THROUGH 00Z THURSDAY...MAINLY VFR WITH A CHANCE FOR
SOME ISOLATED/SCATTERED SHOWERS AS A WARM FRONT APPROACHES.
00Z THURSDAY THROUGH 00Z FRIDAY...VFR TRENDING TO MVFR/IFR IN
SHOWERS AND STORMS AS A WARM FRONT LIFTS ACROSS THE NORTHEAST.
00Z FRIDAY THROUGH 00Z SATURDAY...VFR UNDER SURFACE HIGH PRESSURE.
&&
.EQUIPMENT...
AS OF 1225 PM EDT SATURDAY...NOAA WEATHER RADIO WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
KTYX RADAR HAS RETURNED TO SERVICE. HOWEVER...TECHNICIANS HAVE
DETERMINED THAT ADDITIONAL WORK IS NEEDED AT THE SITE. PARTS ARE
ON ORDER...WITH ADDITIONAL DOWNTIME EXPECTED AS EARLY AS NEXT
WEEK.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...TABER/NF
SHORT TERM...TABER
LONG TERM...EVENSON
AVIATION...LAHIFF
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
105 PM EDT SUN AUG 4 2013
.SYNOPSIS...
A COOLER NORTHWEST FLOW WILL DEVELOP TODAY...ALONG WITH SCATTERED
LIGHT SHOWERS THROUGH EARLY AFTERNOON...MAINLY OVER CENTRAL NEW
YORK. A HIGH PRESSURE SYSTEM WILL THEN BUILD IN TONIGHT THROUGH
MONDAY...WITH MAINLY CLEAR SKIES. VERY COOL TEMPERATURES
OVERNIGHT...WILL MODERATE BACK INTO THE 70S MONDAY AFTERNOON.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
930 AM...LAKE EFFECT CLDS ARE NOW WELL ENTRENCHED IN THE AREA THIS
MRNG. NAM TRIES TO DRY US OUT LTR IN THE AFTN WHILE THE HRRR KEEPS
THE CLDS AND SPRINKLES THRU THE DAY. LEAN TWRDS THE HRRR SOLN AS
IT/S NEVER SMART TO UNDERESTIMATE THE ABILITY OF UPSTATE NY TO
GENERATE CLDS IN A COOL NW FLOW. HAVE LWRD AFTN HI/S A BIT AND
INCRSD CLDS AND PCPN CHANCE.
415 AM UPDATE... WATER VAPOR IMAGERY SHOWS AN UPR LVL TROUGH IN
THE PROCESS OF DEEPENING ACRS THE UPR LKS RGN...SERN CANADA...AND
THE NERN CONUS THIS MRNG. AS THIS EVOLUTION CONTS TDY...A NWLY
FLOW REGIME AND LOW-LVL CAA WILL PREVAIL. THE LATEST MESO`S
ALREADY SHOW 850 MB TEMPS DOWN TO ABT 7C OVER LK ONT...WITH
READINGS PROGGED TO DROP TO 5-6C BY ARND 18Z. GIVEN LK ONT WATER
TEMPS OF 22-24C...ALG WITH THE PRESENCE OF LOW-LVL MOISTURE
TRAPPED UNDER A SUBSIDENCE INVERSION ALOFT...SCTD LK EFF -SHRA
WILL PREVAIL THROUGH MIDDAY-EARLY AFTN. A 290-300 VECTOR FAVORS A
CORRIDOR THROUGH ONONDAGA/SRN CAYUGA/NRN CORTLAND/ONEIDA/MADISON/CHENANGO/
OTSEGO/NRN DELAWARE CNTYS. THESE SHWRS SHOULD DIMINISH BY
18-21Z...AS THE COLUMN BEGINS TO DRY OUT BY THIS TIME.
FARTHER S AND W...ACRS THE TWIN TIERS...THE WYO/LACK VLYS...AND
THE POCONOS...PTLY TO MOSTLY SUNNY SKIES WILL PREVAIL.
AS ALLUDED TO ABV...MAX TEMPS WILL BE COOLER TDY (HIGHS RANGING
FROM THE UPR 60S-MID 70S).
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
430 AM UPDATE... GENERALLY QUIET WX FORESEEN THIS PD...AS RIDGING
BOTH SFC AND ALOFT BUILD IN TNT-MON...GRADUALLY MOVING OFF THE
COAST ON TUE.
THE COMBO OF CLEARING SKIES AND A COOL AMS WILL LEAD TO MIN TEMPS
DOWN TO THE MID 40S IN NORMALLY CHILLIER VLYS LTR TNT/EARLY MON...WITH
PATCHY VLY FOG PSBL ACRS THE TWIN TIERS. AS THE AMS MODIFIES DURG
THE DAY MON...PLENTY OF SUNSHINE SHOULD HELP AFTN TEMPS RECOVER
INTO THE 70S (2-4 DEGS HIGHER THAN ON SUN MOST AREAS).
BY TUE...A RETURN SRLY FLOW DVLPS...LEADING TO WARM AND MOIST
ADVECTION. WE MAY SEE A FEW -SHRA DVLP...BUT MOST OF THESE WILL
LIKELY RESIDE ACRS OUR WRN/SRN ZNS...CLOSER TO PASSING S/WV
ENERGY...AND ALSO AN APPROACHING WARM FRNTL BNDRY. FOR NOW...WE`LL
SIMPLY CALL FOR ISOLD-SCTD SHWRS THESE AREAS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
GDNC COMING INTO BETTER AGREEMENT WITH MID TO LATE WEEK FROPA
ASSCD WITH S/WV ROTATING ARND A CLOSED LOW OVER CNTRL CANADA. SOME
QUESTION ON THE XTNT OF SRN STREAM INFLUENCES ON THIS SYSTEM.
OVERALL...XPCT CDFNT TO PASS MOST OF THE RGN ON THU...ALTHO SOME
LINGERING PCPN PSBL FAR SE ZONES ON FRI CLOSER TO THE RETREATING FNTL
BNDRY. OTRW...HIGH PRES BUILDS INTO THE AREA LATE WEEK INTO NXT
WEEKEND. 2NDRY CDFNT HINTED AT FOR NXT WEEKEND (SAT) BUT IT LOOKS
FAIRLY DRY AT THIS POINT. SO AFTER THURSDAY`S FROPA...GNRLY DRY WX
AND TEMPS AVERAGING NEAR OR A FEW DEG BLO NORMAL. WPC GUIDANCE
LOOKED GOOD AND UTILIZED WITH LTL MODIFICATION.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
630 AM EDT UPDATE...
MVFR LAKE EFFECT CLOUDS HAVE DEVELOPED ACROSS MUCH OF THE REGION
THIS MORNING. CLOUDS ARE EXPECTED TO BECOME MORE DENSE AND
WIDESPREAD AS WEST/NORTHWESTERLY WINDS INCREASE THIS MORNING AND
COLDER AIR MOVES ACROSS THE FINGER LAKES. BY MID AFTERNOON CLOUDS
WILL LIFT TO VFR AND START TO SLOWLY DIMINISH. BY SUNDAY NIGHT THE
MAJORITY OF THE CLOUDS WILL DISSIPATE AND RADIATIONAL COOLING WILL
START TO OCCUR. AS RADIATIONAL COOLING TAKES PLACE FOG WILL
DEVELOP ACROSS CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA. AS THE
NIGHT TRANSITIONS INTO MONDAY MORNING THE FOG WILL BECOME
DENSE...THUS PUT BR IN TAFS FOR KRME... KITH... KELM... AND KBGM
WHERE CONFIDENCE IS HIGHEST WHERE DEVELOPMENT WILL TAKE PLACE.
MON THRU WED...MAINLY VFR.
THU...MVFR IN SHRA AND TSRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...MLJ
SHORT TERM...DGM/MLJ
LONG TERM...
AVIATION...KAH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1035 AM EDT SUN AUG 4 2013
.SYNOPSIS...
A DEEP TROUGH OF LOW PRESSURE CONTINUES ACROSS OUR REGION TODAY WITH
ADDITIONAL SHOWERS WITH EMBEDDED THUNDERSTORMS POSSIBLE.
TEMPERATURES WILL BE 5 TO 10 DEGREES BELOW NORMAL WITH HIGHS MAINLY
IN THE 60S TO NEAR 70. HIGH PRESSURE LOCATED OVER THE CENTRAL GREAT
LAKES WILL SHIFT INTO THE REGION ON MONDAY...WITH CLEARING SKIES AND
COOL TEMPERATURES. A WARMING TREND IS EXPECTED BY THE MIDDLE OF THIS
UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1030 AM EDT SUNDAY...FORECAST APPEARS ON TRACK AND JUST SOME
MINOR EDITS NECESSARY. SCATTERED SHOWERS BEGINNING TO APPEAR AS
SHORT WAVE TROF SWINGS THROUGH. BEST CHANCE FOR SHOWERS WILL BE
NORTHERN VERMONT...THOUGH MOST AREAS WILL SEE SOME SCATTERED
ACTIVITY. BEST CHANCE FOR A T-STORM WILL BE CENTRAL/SOUTHERN
VERMONT TODAY WHERE SUNSHINE APPEARED THIS MORNING AND BEST
INSTABILITY EXISTS. INCREASED TEMPS SLIGHTLY ACROSS THE SOUTHERN
VERMONT TO ACCOUNT FOR ADDITIONAL SUNSHINE...OTHERWISE MINOR
CHANGES.
ONCE AGAIN FCST FOCUS WL BE AREAL COVERAGE/INTENSITY OF
SHOWERS/STORMS TODAY. WATER VAPOR SHOWS DEEP MID/UPPER LVL TROF
ACRS THE NE CONUS...WITH TWO ADDITIONAL S/W`S EXPECTED TO IMPACT
OUR CWA TODAY. FIRST S/W IS LOCATED OVER JUST NORTH OF THE EASTERN
GREAT LAKES...AND WL BE ACRS OUR WESTERN ZNS BTWN 12-15Z
TODAY...MEANWHILE STRONG ENERGY BTWN HUDSON BAY AND NORTHERN GREAT
LAKES WL APPROACH OUR CWA BY 18Z TODAY. THIS PIECE OF ENERGY
DIVING ALONG THE SOUTHERN PERIPHERY OF TROF WL HELP DEVELOP A
CLOSED 5H/7H CIRCULATION OVER SOUTHERN CANADA BY 00Z MONDAY. THIS
CYCLONIC UPSLOPE FLW...ALONG WITH LLVL CAA...AND LEFTOVER 1000 TO
700 MOISTURE WL HELP IN THE DEVELOPMENT OF ADDITIONAL UPSLOPE
SHOWERS THIS EVENING. FOR TODAY...WL CONT TO MENTION LIKELY POPS
WITH GREATEST CHCS ACRS THE NORTHERN/CENTRAL ZNS...WHERE 850 TO
500MB RH IS THE DEEPEST. IN ADDITION...BEST PVA ASSOCIATED WITH 5H
VORT AND NOSE OF 25H JET IS ACRS THIS REGION. LATEST RAP SOUNDINGS
CONT TO SUPPORT SOME SFC HEATING RESULTING IN CAPE VALUES BTWN 800
AND 1200 J/KG...AND LIS AROUND -2C...FROM DEVELOPING COLD POOL
ALOFT. THIS INSTABILITY SHOULD PROMOTE STRONG ENOUGH UPDRAFTS TO
SUPPORT MENTION OF THUNDER...ESPECIALLY MTNS AND NORTHERN CWA. THE
COMBINATION OF LOW WET BULB ZERO HEIGHTS ASSOCIATED WITH COLD
THERMAL PROFILES...SOME SMALL HAIL WL BE POSSIBLE...IN ADDITION TO
LOCALIZED WIND GUSTS TO 30 MPH. THE LACK OF INSTABILITY WL KEEP
STORMS BLW SVR LIMITS THIS AFTN AND LIMITED DEEP MOISTURE WL LIMIT
AREAL COVERAGE. WL MENTION CHCS IN HWO...BUT NOT ZONES ATTM. CWMW
SOUNDING SHOWS 1000 TO 850MB TEMPS BTWN 1 AND 3C COOLER THAN 24HR
AGO...SUPPORTING HIGHS ONLY IN THE 60S MTNS TO NEAR 70F VALLEYS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
AS OF 415 AM EDT SUNDAY...LARGE SCALE SYNOPTIC FORCING FROM
POTENT 5H VORT WL TRANSITION TO MESOSCALE UPSLOPE LIFT AS CYCLONIC
NW FLW CONTS ACRS OUR REGION TONIGHT. EXPECT AREAL COVERAGE/INTENSITY OF
PRECIP TO QUICKLY DISSIPATE BY 00Z THIS EVENING...WITH
PRECIP CONFINED ALONG THE UPSLOPE REGIONS OF THE NORTHERN DACKS AND
CENTRAL/GREEN MTNS. UPSLOPE PROCEDURE SHOWS GOOD 1000 TO 700MB
RH...FAVORABLE SFC TO 700MB FLW OF 20 TO 30 KNOTS...AND ASSOCIATED
ENHANCED UVVS ACRS THE WESTERN SLOPES. WL MENTION LIKELY POPS THRU
03Z ACRS THE MTNS...WITH SCHC/CHC POPS ELSEWHERE...AFT 03Z DEEP
LAYER MOISTURE QUICKLY DECREASES AS SUBSIDENCE DEVELOPS. THIS WL
RESULT IN CLRING SKIES IN MOST LOCATIONS BY MORNING...EXCEPT
NORTHERN VT. LLVL CAA RESULTS IN PROGGED 85H TEMPS BTWN 2-4C BY
12Z MONDAY...WITH GOOD BL MIXING. THIS WL SUPPORT ADVECTION TYPE
COOLING WITH LOWS RANGING FROM THE U30S SLK TO NEAR 50F CPV. IF
WINDS DECOUPLE AT SLK...COULD SEE TEMPS DROP INTO THE MID 30S BY
12Z MONDAY.
MONDAY AND TUESDAY...SFC HIGH PRES BUILDING ACRS OUR CWA WL RESULT
IN DRY CONDITIONS AND BLW NORMAL TEMPS. THERMAL SOUNDINGS SUGGEST
MORE OF A FALL LIKE TEMP PROFILE ON MONDAY. PROGGED 85H TEMPS BTWN
4-6C...WITH MOSTLY SUNNY SKIES SUPPORT HIGHS 60S TO NEAR 70 MOST
LOCATIONS. A CHILLY NIGHT IS EXPECTED ON MONDAY NIGHT/TUES MORNING
WITH LOWS RANGING FROM M30S SLK/LAKE PLACID/NEK TO M/U 40S CPV...AND
MID 50S NEAR THE LAKE. TUESDAY...WEAK LLVL WAA DEVELOPS WITH MAINLY
CLR SKIES AND TEMPS IN THE 70S. INTERESTING TO SEE THE GOOD MIXING
ON MONDAY AFTN...AND HOW THE SFC DWPTS DROP INTO THE M/U 30S...VERY
DRY AIR IS PROGGED TO MIX DOWN....RESULTING IN LOW RH VALUES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 415 AM EDT SUNDAY...LARGE UPPER TROUGH TAKES SHAPE OVER CENTRAL
CANADA AND THE UPPER MIDWEST TUESDAY NIGHT INTO WEDNESDAY
MORNING. THIS WILL HELP TO BACK THE UPPER FLOW TO THE WEST AND
SOUTHWEST ON WEDNESDAY. THIS WILL ALLOW 850/925 MILLIBAR
TEMPERATURES TO RISE AND LOOKING AT HIGH TEMPERATURES RIGHT AROUND
SEASONAL NORMALS WEDNESDAY. CLOUDS WILL ALSO BE ON THE INCREASE
AND THERE COULD BE SOME AFTERNOON THUNDERSTORMS...BUT IT APPEARS
BEST DYNAMIC SUPPORT/SURFACE COLD FRONT DO NOT MOVE INTO THE AREA
UNTIL WEDNESDAY NIGHT AND THURSDAY. GOING FORECAST HAS THIS IDEA
COVERED WELL AND HAVE CONTINUED THIS THINKING IN THE GRIDS.
FORCING/COLD FRONT MOVE EAST OF THE AREA THURSDAY NIGHT FOR A
DRYING TREND AND PRONOUNCED WESTERLY FLOW ALOFT DEVELOPS OVER THE
AREA ON FRIDAY. LOW LEVEL THERMAL PROFILE SHOWS WARMEST READINGS
OF THE WEEK MOVE INTO THE AREA ON FRIDAY. THIS WILL PRODUCE HIGH
TEMPERATURES AT OR SLIGHTLY ABOVE SEASONAL NORMALS. AN UPPER LEVEL
DISTURBANCE WILL APPROACH THE AREA LATER ON SATURDAY... BUT BEST
FORCING LOOKS TO STAY UP IN CANADA...THUS GOING FORECAST OF A
SLIGHT CHANCE OF SHOWERS LOOKS GOOD.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
THROUGH 12Z MONDAY...TRENDS THROUGH 15Z WILL TAKE CEILINGS FROM
THE VFR CATEGORY DOWN INTO THE MVFR CATEGORY AND CEILINGS WILL
REMAIN IN THE MVFR CATEGORY THROUGH THE REMAINDER OF THE PERIOD.
THE ONLY EXCEPTION TO THIS WILL BE KSLK WHICH WILL START IN THE
IFR CATEGORY AND INCREASE UP INTO THE MVFR CATEGORY. SCATTERED
SHOWERS WILL MOVE DOWN FROM SOUTHERN QUEBEC PROVINCE AND ACROSS
THE AREA BETWEEN 15Z AND 02Z. HOWEVER...VISIBILITIES WILL REMAIN
IN THE VFR CATEGORY. WINDS WILL INCREASE INTO THE 10 TO 15 KNOT
RANGE BY 14Z...BUT WILL TAPER OFF UNDER 10 KNOTS AFTER 00Z.
OUTLOOK 12Z MONDAY THROUGH THURSDAY...
12Z MONDAY THROUGH 00Z THURSDAY...VFR UNDER SURFACE HIGH PRESSURE.
00Z THURSDAY THROUGH 00Z FRIDAY...VFR TRENDING TO MVFR/IFR IN
SHOWERS AND STORMS AS A WARM FRONT LIFTS ACROSS THE NORTHEAST.
&&
.EQUIPMENT...
AS OF 1225 PM EDT SATURDAY...NOAA WEATHER RADIO WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
KTYX RADAR HAS RETURNED TO SERVICE. HOWEVER...TECHNICIANS HAVE
DETERMINED THAT ADDITIONAL WORK IS NEEDED AT THE SITE. PARTS ARE
ON ORDER...WITH ADDITIONAL DOWNTIME EXPECTED AS EARLY AS NEXT
WEEK.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...TABER/NF
SHORT TERM...TABER
LONG TERM...EVENSON
AVIATION...EVENSON/LAHIFF
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
934 AM EDT SUN AUG 4 2013
.SYNOPSIS...
A COOLER NORTHWEST FLOW WILL DEVELOP TODAY...ALONG WITH SCATTERED
LIGHT SHOWERS THROUGH EARLY AFTERNOON...MAINLY OVER CENTRAL NEW
YORK. A HIGH PRESSURE SYSTEM WILL THEN BUILD IN TONIGHT THROUGH
MONDAY...WITH MAINLY CLEAR SKIES. VERY COOL TEMPERATURES
OVERNIGHT...WILL MODERATE BACK INTO THE 70S MONDAY AFTERNOON.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
930 AM...LAKE EFFECT CLDS ARE NOW WELL ENTRENCHED IN THE AREA THIS
MRNG. NAM TRIES TO DRY US OUT LTR IN THE AFTN WHILE THE HRRR KEEPS
THE CLDS AND SPRINKLES THRU THE DAY. LEAN TWRDS THE HRRR SOLN AS
IT/S NEVER SMART TO UNDERESTIMATE THE ABILITY OF UPSTATE NY TO
GENERATE CLDS IN A COOL NW FLOW. HAVE LWRD AFTN HI/S A BIT AND
INCRSD CLDS AND PCPN CHANCE.
415 AM UPDATE... WATER VAPOR IMAGERY SHOWS AN UPR LVL TROUGH IN
THE PROCESS OF DEEPENING ACRS THE UPR LKS RGN...SERN CANADA...AND
THE NERN CONUS THIS MRNG. AS THIS EVOLUTION CONTS TDY...A NWLY
FLOW REGIME AND LOW-LVL CAA WILL PREVAIL. THE LATEST MESO`S
ALREADY SHOW 850 MB TEMPS DOWN TO ABT 7C OVER LK ONT...WITH
READINGS PROGGED TO DROP TO 5-6C BY ARND 18Z. GIVEN LK ONT WATER
TEMPS OF 22-24C...ALG WITH THE PRESENCE OF LOW-LVL MOISTURE
TRAPPED UNDER A SUBSIDENCE INVERSION ALOFT...SCTD LK EFF -SHRA
WILL PREVAIL THROUGH MIDDAY-EARLY AFTN. A 290-300 VECTOR FAVORS A
CORRIDOR THROUGH ONONDAGA/SRN CAYUGA/NRN CORTLAND/ONEIDA/MADISON/CHENANGO/
OTSEGO/NRN DELAWARE CNTYS. THESE SHWRS SHOULD DIMINISH BY
18-21Z...AS THE COLUMN BEGINS TO DRY OUT BY THIS TIME.
FARTHER S AND W...ACRS THE TWIN TIERS...THE WYO/LACK VLYS...AND
THE POCONOS...PTLY TO MOSTLY SUNNY SKIES WILL PREVAIL.
AS ALLUDED TO ABV...MAX TEMPS WILL BE COOLER TDY (HIGHS RANGING
FROM THE UPR 60S-MID 70S).
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
430 AM UPDATE... GENERALLY QUIET WX FORESEEN THIS PD...AS RIDGING
BOTH SFC AND ALOFT BUILD IN TNT-MON...GRADUALLY MOVING OFF THE
COAST ON TUE.
THE COMBO OF CLEARING SKIES AND A COOL AMS WILL LEAD TO MIN TEMPS
DOWN TO THE MID 40S IN NORMALLY CHILLIER VLYS LTR TNT/EARLY MON...WITH
PATCHY VLY FOG PSBL ACRS THE TWIN TIERS. AS THE AMS MODIFIES DURG
THE DAY MON...PLENTY OF SUNSHINE SHOULD HELP AFTN TEMPS RECOVER
INTO THE 70S (2-4 DEGS HIGHER THAN ON SUN MOST AREAS).
BY TUE...A RETURN SRLY FLOW DVLPS...LEADING TO WARM AND MOIST
ADVECTION. WE MAY SEE A FEW -SHRA DVLP...BUT MOST OF THESE WILL
LIKELY RESIDE ACRS OUR WRN/SRN ZNS...CLOSER TO PASSING S/WV
ENERGY...AND ALSO AN APPROACHING WARM FRNTL BNDRY. FOR NOW...WE`LL
SIMPLY CALL FOR ISOLD-SCTD SHWRS THESE AREAS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
630 AM EDT UPDATE...
FORECAST IS IN GOOD SHAPE. MINOR CHANGES WERE MADE.
PREVIOUS UPDATE...
RISING HGTS ON TUE WILL RESULT IN SOME INCRSG CLDS BUT
SHWRS SHD BE LIMITED DUE TO STUBBORN LL DRY AIR. YET ANOTHER
DIGGING LOW APCHS FOR WED AND THU AND PUSHES A SFC BNDRY THRU THE
AREA. GOOD GULF CONNECTIONS SHD LEAD TO GOOD CVRG OF SHWRS AND
TRWS LATE WED INTO THU AHD OF THE TROF. DRIER AND COOLER AIR
RETURNS ON FRI BHD THE FNT. ATTM IT LOOKS DRY BHD THE FNT BUT
EVENTUALLY THE LWRG HGTS WITH THE LRG UA LOW WILL RESULT IN MAINLY
AFTN CONV.
TEMPS WILL CONT TO AVG WELL BLO SEASONAL NORMS THRU THE PD. MEX
GUID WAS RUNNING A BIT HIER THRU THE PD THAN HPC BUT SEEMED LIKE
THE COOLER EURO HAD A BETTER HANDLE ON THE UA LOW SO MORE CLOSELY
FLWD HPC GUID.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
630 AM EDT UPDATE...
MVFR LAKE EFFECT CLOUDS HAVE DEVELOPED ACROSS MUCH OF THE REGION
THIS MORNING. CLOUDS ARE EXPECTED TO BECOME MORE DENSE AND
WIDESPREAD AS WEST/NORTHWESTERLY WINDS INCREASE THIS MORNING AND
COLDER AIR MOVES ACROSS THE FINGER LAKES. BY MID AFTERNOON CLOUDS
WILL LIFT TO VFR AND START TO SLOWLY DIMINISH. BY SUNDAY NIGHT THE
MAJORITY OF THE CLOUDS WILL DISSIPATE AND RADIATIONAL COOLING WILL
START TO OCCUR. AS RADIATIONAL COOLING TAKES PLACE FOG WILL
DEVELOP ACROSS CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA. AS THE
NIGHT TRANSITIONS INTO MONDAY MORNING THE FOG WILL BECOME
DENSE...THUS PUT BR IN TAFS FOR KRME... KITH... KELM... AND KBGM
WHERE CONFIDENCE IS HIGHEST WHERE DEVELOPMENT WILL TAKE PLACE.
MON THRU WED...MAINLY VFR.
THU...MVFR IN SHRA AND TSRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...MLJ
SHORT TERM...DGM/MLJ
LONG TERM...DGM
AVIATION...KAH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
734 AM EDT SUN AUG 4 2013
.SYNOPSIS...
A DEEP TROUGH OF LOW PRESSURE CONTINUES ACROSS OUR REGION TODAY WITH
ADDITIONAL SHOWERS WITH EMBEDDED THUNDERSTORMS POSSIBLE.
TEMPERATURES WILL BE 5 TO 10 DEGREES BELOW NORMAL WITH HIGHS MAINLY
IN THE 60S TO NEAR 70. HIGH PRESSURE LOCATED OVER THE CENTRAL GREAT
LAKES WILL SHIFT INTO THE REGION ON MONDAY...WITH CLEARING SKIES AND
COOL TEMPERATURES. A WARMING TREND IS EXPECTED BY THE MIDDLE OF THIS
UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 706 AM EDT SUNDAY...MINOR UPDATE FOR CRNT OBS AND LATEST
RADAR/SATL TRENDS. OBS SHOW LIGHT RAIN ALREADY AT
MONTREAL...ASSOCIATED WITH NEXT S/W. EXPECT AREAL COVERAGE OF
PRECIP TO INCREASE ACRS OUR NORTHERN CWA BTWN 14-16Z. TEMPS WL
SLOWLY WARM INTO THE 60S TO NEAR 70F BY THIS AFTN.
ONCE AGAIN FCST FOCUS WL BE AREAL COVERAGE/INTENSITY OF
SHOWERS/STORMS TODAY. WATER VAPOR SHOWS DEEP MID/UPPER LVL TROF
ACRS THE NE CONUS...WITH TWO ADDITIONAL S/W`S EXPECTED TO IMPACT
OUR CWA TODAY. FIRST S/W IS LOCATED OVER JUST NORTH OF THE EASTERN
GREAT LAKES...AND WL BE ACRS OUR WESTERN ZNS BTWN 12-15Z
TODAY...MEANWHILE STRONG ENERGY BTWN HUDSON BAY AND NORTHERN GREAT
LAKES WL APPROACH OUR CWA BY 18Z TODAY. THIS PIECE OF ENERGY
DIVING ALONG THE SOUTHERN PERIPHERY OF TROF WL HELP DEVELOP A
CLOSED 5H/7H CIRCULATION OVER SOUTHERN CANADA BY 00Z MONDAY. THIS
CYCLONIC UPSLOPE FLW...ALONG WITH LLVL CAA...AND LEFTOVER 1000 TO
700 MOISTURE WL HELP IN THE DEVELOPMENT OF ADDITIONAL UPSLOPE
SHOWERS THIS EVENING. FOR TODAY...WL CONT TO MENTION LIKELY POPS
WITH GREATEST CHCS ACRS THE NORTHERN/CENTRAL ZNS...WHERE 850 TO
500MB RH IS THE DEEPEST. IN ADDITION...BEST PVA ASSOCIATED WITH 5H
VORT AND NOSE OF 25H JET IS ACRS THIS REGION. LATEST RAP SOUNDINGS
CONT TO SUPPORT SOME SFC HEATING RESULTING IN CAPE VALUES BTWN 800
AND 1200 J/KG...AND LIS AROUND -2C...FROM DEVELOPING COLD POOL
ALOFT. THIS INSTABILITY SHOULD PROMOTE STRONG ENOUGH UPDRAFTS TO
SUPPORT MENTION OF THUNDER...ESPECIALLY MTNS AND NORTHERN CWA. THE
COMBINATION OF LOW WET BULB ZERO HEIGHTS ASSOCIATED WITH COLD
THERMAL PROFILES...SOME SMALL HAIL WL BE POSSIBLE...IN ADDITION TO
LOCALIZED WIND GUSTS TO 30 MPH. THE LACK OF INSTABILITY WL KEEP
STORMS BLW SVR LIMITS THIS AFTN AND LIMITED DEEP MOISTURE WL LIMIT
AREAL COVERAGE. WL MENTION CHCS IN HWO...BUT NOT ZONES ATTM. CWMW
SOUNDING SHOWS 1000 TO 850MB TEMPS BTWN 1 AND 3C COOLER THAN 24HR
AGO...SUPPORTING HIGHS ONLY IN THE 60S MTNS TO NEAR 70F VALLEYS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
AS OF 415 AM EDT SUNDAY...LARGE SCALE SYNOPTIC FORCING FROM
POTENT 5H VORT WL TRANSITION TO MESOSCALE UPSLOPE LIFT AS CYCLONIC
NW FLW CONTS ACRS OUR REGION TONIGHT. EXPECT AREAL COVERAGE/INTENSITY OF
PRECIP TO QUICKLY DISSIPATE BY 00Z THIS EVENING...WITH
PRECIP CONFINED ALONG THE UPSLOPE REGIONS OF THE NORTHERN DACKS AND
CENTRAL/GREEN MTNS. UPSLOPE PROCEDURE SHOWS GOOD 1000 TO 700MB
RH...FAVORABLE SFC TO 700MB FLW OF 20 TO 30 KNOTS...AND ASSOCIATED
ENHANCED UVVS ACRS THE WESTERN SLOPES. WL MENTION LIKELY POPS THRU
03Z ACRS THE MTNS...WITH SCHC/CHC POPS ELSEWHERE...AFT 03Z DEEP
LAYER MOISTURE QUICKLY DECREASES AS SUBSIDENCE DEVELOPS. THIS WL
RESULT IN CLRING SKIES IN MOST LOCATIONS BY MORNING...EXCEPT
NORTHERN VT. LLVL CAA RESULTS IN PROGGED 85H TEMPS BTWN 2-4C BY
12Z MONDAY...WITH GOOD BL MIXING. THIS WL SUPPORT ADVECTION TYPE
COOLING WITH LOWS RANGING FROM THE U30S SLK TO NEAR 50F CPV. IF
WINDS DECOUPLE AT SLK...COULD SEE TEMPS DROP INTO THE MID 30S BY
12Z MONDAY.
MONDAY AND TUESDAY...SFC HIGH PRES BUILDING ACRS OUR CWA WL RESULT
IN DRY CONDITIONS AND BLW NORMAL TEMPS. THERMAL SOUNDINGS SUGGEST
MORE OF A FALL LIKE TEMP PROFILE ON MONDAY. PROGGED 85H TEMPS BTWN
4-6C...WITH MOSTLY SUNNY SKIES SUPPORT HIGHS 60S TO NEAR 70 MOST
LOCATIONS. A CHILLY NIGHT IS EXPECTED ON MONDAY NIGHT/TUES MORNING
WITH LOWS RANGING FROM M30S SLK/LAKE PLACID/NEK TO M/U 40S CPV...AND
MID 50S NEAR THE LAKE. TUESDAY...WEAK LLVL WAA DEVELOPS WITH MAINLY
CLR SKIES AND TEMPS IN THE 70S. INTERESTING TO SEE THE GOOD MIXING
ON MONDAY AFTN...AND HOW THE SFC DWPTS DROP INTO THE M/U 30S...VERY
DRY AIR IS PROGGED TO MIX DOWN....RESULTING IN LOW RH VALUES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 415 AM EDT SUNDAY...LARGE UPPER TROUGH TAKES SHAPE OVER CENTRAL
CANADA AND THE UPPER MIDWEST TUESDAY NIGHT INTO WEDNESDAY
MORNING. THIS WILL HELP TO BACK THE UPPER FLOW TO THE WEST AND
SOUTHWEST ON WEDNESDAY. THIS WILL ALLOW 850/925 MILLIBAR
TEMPERATURES TO RISE AND LOOKING AT HIGH TEMPERATURES RIGHT AROUND
SEASONAL NORMALS WEDNESDAY. CLOUDS WILL ALSO BE ON THE INCREASE
AND THERE COULD BE SOME AFTERNOON THUNDERSTORMS...BUT IT APPEARS
BEST DYNAMIC SUPPORT/SURFACE COLD FRONT DO NOT MOVE INTO THE AREA
UNTIL WEDNESDAY NIGHT AND THURSDAY. GOING FORECAST HAS THIS IDEA
COVERED WELL AND HAVE CONTINUED THIS THINKING IN THE GRIDS.
FORCING/COLD FRONT MOVE EAST OF THE AREA THURSDAY NIGHT FOR A
DRYING TREND AND PRONOUNCED WESTERLY FLOW ALOFT DEVELOPS OVER THE
AREA ON FRIDAY. LOW LEVEL THERMAL PROFILE SHOWS WARMEST READINGS
OF THE WEEK MOVE INTO THE AREA ON FRIDAY. THIS WILL PRODUCE HIGH
TEMPERATURES AT OR SLIGHTLY ABOVE SEASONAL NORMALS. AN UPPER LEVEL
DISTURBANCE WILL APPROACH THE AREA LATER ON SATURDAY... BUT BEST
FORCING LOOKS TO STAY UP IN CANADA...THUS GOING FORECAST OF A
SLIGHT CHANCE OF SHOWERS LOOKS GOOD.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
THROUGH 12Z MONDAY...TRENDS THROUGH 15Z WILL TAKE CEILINGS FROM
THE VFR CATEGORY DOWN INTO THE MVFR CATEGORY AND CEILINGS WILL
REMAIN IN THE MVFR CATEGORY THROUGH THE REMAINDER OF THE PERIOD.
THE ONLY EXCEPTION TO THIS WILL BE KSLK WHICH WILL START IN THE
IFR CATEGORY AND INCREASE UP INTO THE MVFR CATEGORY. SCATTERED
SHOWERS WILL MOVE DOWN FROM SOUTHERN QUEBEC PROVINCE AND ACROSS
THE AREA BETWEEN 15Z AND 02Z. HOWEVER...VISIBILITIES WILL REMAIN
IN THE VFR CATEGORY. WINDS WILL INCREASE INTO THE 10 TO 15 KNOT
RANGE BY 14Z...BUT WILL TAPER OFF UNDER 10 KNOTS AFTER 00Z.
OUTLOOK 12Z MONDAY THROUGH THURSDAY...
12Z MONDAY THROUGH 00Z THURSDAY...VFR UNDER SURFACE HIGH PRESSURE.
00Z THURSDAY THROUGH 00Z FRIDAY...VFR TRENDING TO MVFR/IFR IN
SHOWERS AND STORMS AS A WARM FRONT LIFTS ACROSS THE NORTHEAST.
&&
.EQUIPMENT...
AS OF 1225 PM EDT SATURDAY...NOAA WEATHER RADIO WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
KTYX RADAR HAS RETURNED TO SERVICE. HOWEVER...TECHNICIANS HAVE
DETERMINED THAT ADDITIONAL WORK IS NEEDED AT THE SITE. PARTS ARE
ON ORDER...WITH ADDITIONAL DOWNTIME EXPECTED AS EARLY AS NEXT
WEEK.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...TABER
SHORT TERM...TABER
LONG TERM...EVENSON
AVIATION...EVENSON/LAHIFF
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
417 AM EDT SUN AUG 4 2013
.SYNOPSIS...
A DEEP TROUGH OF LOW PRESSURE CONTINUES ACROSS OUR REGION TODAY WITH
ADDITIONAL SHOWERS WITH EMBEDDED THUNDERSTORMS POSSIBLE.
TEMPERATURES WILL BE 5 TO 10 DEGREES BELOW NORMAL WITH HIGHS MAINLY
IN THE 60S TO NEAR 70. HIGH PRESSURE LOCATED OVER THE CENTRAL GREAT
LAKES WILL SHIFT INTO THE REGION ON MONDAY...WITH CLEARING SKIES AND
COOL TEMPERATURES. A WARMING TREND IS EXPECTED BY THE MIDDLE OF THIS
UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 415 AM EDT SUNDAY...ONCE AGAIN FCST FOCUS WL BE AREAL
COVERAGE/INTENSITY OF SHOWERS/STORMS TODAY. WATER VAPOR SHOWS
DEEP MID/UPPER LVL TROF ACRS THE NE CONUS...WITH TWO ADDITIONAL
S/W`S EXPECTED TO IMPACT OUR CWA TODAY. FIRST S/W IS LOCATED OVER
JUST NORTH OF THE EASTERN GREAT LAKES...AND WL BE ACRS OUR WESTERN
ZNS BTWN 12-15Z TODAY...MEANWHILE STRONG ENERGY BTWN HUDSON BAY
AND NORTHERN GREAT LAKES WL APPROACH OUR CWA BY 18Z TODAY. THIS
PIECE OF ENERGY DIVING ALONG THE SOUTHERN PERIPHERY OF TROF WL
HELP DEVELOP A CLOSED 5H/7H CIRCULATION OVER SOUTHERN CANADA BY
00Z MONDAY. THIS CYCLONIC UPSLOPE FLW...ALONG WITH LLVL CAA...AND
LEFTOVER 1000 TO 700 MOISTURE WL HELP IN THE DEVELOPMENT OF
ADDITIONAL UPSLOPE SHOWERS THIS EVENING. FOR TODAY...WL CONT TO
MENTION LIKELY POPS WITH GREATEST CHCS ACRS THE NORTHERN/CENTRAL
ZNS...WHERE 850 TO 500MB RH IS THE DEEPEST. IN ADDITION...BEST PVA
ASSOCIATED WITH 5H VORT AND NOSE OF 25H JET IS ACRS THIS REGION.
LATEST RAP SOUNDINGS CONT TO SUPPORT SOME SFC HEATING RESULTING IN
CAPE VALUES BTWN 800 AND 1200 J/KG...AND LIS AROUND -2C...FROM
DEVELOPING COLD POOL ALOFT. THIS INSTABILITY SHOULD PROMOTE STRONG
ENOUGH UPDRAFTS TO SUPPORT MENTION OF THUNDER...ESPECIALLY MTNS
AND NORTHERN CWA. THE COMBINATION OF LOW WET BULB ZERO HEIGHTS
ASSOCIATED WITH COLD THERMAL PROFILES...SOME SMALL HAIL WL BE
POSSIBLE...IN ADDITION TO LOCALIZED WIND GUSTS TO 30 MPH. THE LACK
OF INSTABILITY WL KEEP STORMS BLW SVR LIMITS THIS AFTN AND LIMITED
DEEP MOISTURE WL LIMIT AREAL COVERAGE. WL MENTION CHCS IN
HWO...BUT NOT ZONES ATTM. CWMW SOUNDING SHOWS 1000 TO 850MB TEMPS
BTWN 1 AND 3C COOLER THAN 24HR AGO...SUPPORTING HIGHS ONLY IN THE
60S MTNS TO NEAR 70F VALLEYS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
AS OF 415 AM EDT SUNDAY...LARGE SCALE SYNOPTIC FORCING FROM
POTENT 5H VORT WL TRANSITION TO MESOSCALE UPSLOPE LIFT AS CYCLONIC
NW FLW CONTS ACRS OUR REGION TONIGHT. EXPECT AREAL COVERAGE/INTENSITY OF
PRECIP TO QUICKLY DISSIPATE BY 00Z THIS EVENING...WITH
PRECIP CONFINED ALONG THE UPSLOPE REGIONS OF THE NORTHERN DACKS AND
CENTRAL/GREEN MTNS. UPSLOPE PROCEDURE SHOWS GOOD 1000 TO 700MB
RH...FAVORABLE SFC TO 700MB FLW OF 20 TO 30 KNOTS...AND ASSOCIATED
ENHANCED UVVS ACRS THE WESTERN SLOPES. WL MENTION LIKELY POPS THRU
03Z ACRS THE MTNS...WITH SCHC/CHC POPS ELSEWHERE...AFT 03Z DEEP
LAYER MOISTURE QUICKLY DECREASES AS SUBSIDENCE DEVELOPS. THIS WL
RESULT IN CLRING SKIES IN MOST LOCATIONS BY MORNING...EXCEPT
NORTHERN VT. LLVL CAA RESULTS IN PROGGED 85H TEMPS BTWN 2-4C BY
12Z MONDAY...WITH GOOD BL MIXING. THIS WL SUPPORT ADVECTION TYPE
COOLING WITH LOWS RANGING FROM THE U30S SLK TO NEAR 50F CPV. IF
WINDS DECOUPLE AT SLK...COULD SEE TEMPS DROP INTO THE MID 30S BY
12Z MONDAY.
MONDAY AND TUESDAY...SFC HIGH PRES BUILDING ACRS OUR CWA WL RESULT
IN DRY CONDITIONS AND BLW NORMAL TEMPS. THERMAL SOUNDINGS SUGGEST
MORE OF A FALL LIKE TEMP PROFILE ON MONDAY. PROGGED 85H TEMPS BTWN
4-6C...WITH MOSTLY SUNNY SKIES SUPPORT HIGHS 60S TO NEAR 70 MOST
LOCATIONS. A CHILLY NIGHT IS EXPECTED ON MONDAY NIGHT/TUES MORNING
WITH LOWS RANGING FROM M30S SLK/LAKE PLACID/NEK TO M/U 40S CPV...AND
MID 50S NEAR THE LAKE. TUESDAY...WEAK LLVL WAA DEVELOPS WITH MAINLY
CLR SKIES AND TEMPS IN THE 70S. INTERESTING TO SEE THE GOOD MIXING
ON MONDAY AFTN...AND HOW THE SFC DWPTS DROP INTO THE M/U 30S...VERY
DRY AIR IS PROGGED TO MIX DOWN....RESULTING IN LOW RH VALUES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 415 AM EDT SUNDAY...LARGE UPPER TROUGH TAKES SHAPE OVER CENTRAL
CANADA AND THE UPPER MIDWEST TUESDAY NIGHT INTO WEDNESDAY
MORNING. THIS WILL HELP TO BACK THE UPPER FLOW TO THE WEST AND
SOUTHWEST ON WEDNESDAY. THIS WILL ALLOW 850/925 MILLIBAR
TEMPERATURES TO RISE AND LOOKING AT HIGH TEMPERATURES RIGHT AROUND
SEASONAL NORMALS WEDNESDAY. CLOUDS WILL ALSO BE ON THE INCREASE
AND THERE COULD BE SOME AFTERNOON THUNDERSTORMS...BUT IT APPEARS
BEST DYNAMIC SUPPORT/SURFACE COLD FRONT DO NOT MOVE INTO THE AREA
UNTIL WEDNESDAY NIGHT AND THURSDAY. GOING FORECAST HAS THIS IDEA
COVERED WELL AND HAVE CONTINUED THIS THINKING IN THE GRIDS.
FORCING/COLD FRONT MOVE EAST OF THE AREA THURSDAY NIGHT FOR A
DRYING TREND AND PRONOUNCED WESTERLY FLOW ALOFT DEVELOPS OVER THE
AREA ON FRIDAY. LOW LEVEL THERMAL PROFILE SHOWS WARMEST READINGS
OF THE WEEK MOVE INTO THE AREA ON FRIDAY. THIS WILL PRODUCE HIGH
TEMPERATURES AT OR SLIGHTLY ABOVE SEASONAL NORMALS. AN UPPER LEVEL
DISTURBANCE WILL APPROACH THE AREA LATER ON SATURDAY... BUT BEST
FORCING LOOKS TO STAY UP IN CANADA...THUS GOING FORECAST OF A
SLIGHT CHANCE OF SHOWERS LOOKS GOOD.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
THROUGH 06Z MONDAY...VFR CONDITIONS ARE EXPECTED THROUGH
14Z...THEN AN UPPER LEVEL DISTURBANCE DROPS DOWN FROM CANADA AND ENHANCES
THE POTENTIAL FOR PRECIPITATION RIGHT THROUGH 02Z. THE SHOWERS WILL
GENERALLY BE LIGHT AND VISIBILITIES WILL REMAIN IN THE VFR CATEGORY.
HOWEVER...VISIBILITIES WILL LOWER INTO THE MVFR CATEGORY AFTER 14Z
AND REMAIN THERE FOR THE REMAINDER OF THE PERIOD. LIGHT WINDS EARLY
THIS MORNING WILL BECOME NORTHWEST AFTER 12Z AT SPEEDS AROUND 10
KNOTS THROUGH MUCH OF THE REMAINDER OF THE PERIOD.
OUTLOOK 06Z MONDAY THROUGH THURSDAY...
06Z MONDAY THROUGH 00Z THURSDAY...VFR UNDER SURFACE HIGH PRESSURE.
00Z THURSDAY THROUGH 00Z FRIDAY...VFR TRENDING TO MVFR/IFR IN
SHOWERS AND STORMS AS A WARM FRONT LIFTS ACROSS THE NORTHEAST.
&&
.EQUIPMENT...
AS OF 1225 PM EDT SATURDAY...NOAA WEATHER RADIO WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
KTYX RADAR HAS RETURNED TO SERVICE. HOWEVER...TECHNICIANS HAVE
DETERMINED THAT ADDITIONAL WORK IS NEEDED AT THE SITE. PARTS ARE
ON ORDER...WITH ADDITIONAL DOWNTIME EXPECTED AS EARLY AS NEXT
WEEK.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...TABER
SHORT TERM...TABER
LONG TERM...EVENSON
AVIATION...EVENSON/LAHIFF
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
148 AM EDT SUN AUG 4 2013
.SYNOPSIS...
COOL HIGH PRESSURE WILL MOVE OVER NY AND PA TO START THE NEW WEEK.
CHILLY AIR FLOWING OVER THE WARM LAKES WILL PRODUCE A FEW
SPRINKLES OR SHOWERS OVER NORTHERN PORTIONS OF OUR REGION ON
SUNDAY. MILDER AIR AND A FEW SHOWERS ARE EXPECTED TUESDAY, AS
MOISTURE RETURNS FROM THE SOUTH.
&&
.NEAR TERM /THROUGH TODAY/...
945 PM UPDATE...
SHOWER ACTIVITY ALONG THE CENTRAL/NORTHERN PA FRONTAL REMNANTS IS
DIMINISHING, WHILE NEW ACTIVITY IS POPPING UP OVER NORTHERN NY
AHEAD OF APPROACHING SHORT WAVE.
MINOR CHANGES TO THE POP/TEMP GRIDS OVERNIGHT TO REFLECT OBSERVED
TRENDS. OTHERWISE, THINKING REMAINS THE SAME - APPROACHING SHORT
WAVE WILL DESTABILIZE LOWER ATMOSPHERE OVER NORTHERN NY. COOL AIR
FLOWING OVER RELATIVELY WARM LAKE WATERS WILL CAUSE LAKE EFFECT OR
ENHANCED SHOWERS AND SPRINKLES INTO SUNDAY.
PREV DISC...
RADAR WAS LARGELY FREE OF ECHOES EARLY THIS AFTERNOON EXCEPT FOR A
FEW VERY ISLD SHRA OCCASIONALLY POPPING UP HERE AND THERE BUT
BEING SHORT-LIVED. ACVTY SEEMS TO BE A TAD MORE PREVALENT IN NE
PA NR SFC FRNT WHICH EXTENDED FROM NRN CATSKILLS TO BTWN IPT AND
AVP IN NE PA IN OUR FORECAST AREA. WATER VAPOR IMAGERY SHOWS
SIGNIFICANT UPPER LEVEL WAVE MOVG ACRS NRN NEW ENGLAND AND SERN
CANADA. THIS WAVE WAS ENHANCING STRG UPR CONFLUENCE ACRS NEW
ENGLAND TO NOVA SCOTIA AND HENCE AN UPPER LEVEL JET STREAK WAS
POSITIONED IN THIS AREA. ENHANCED DVRG IN THE RR QUAD OF THE JET
WAS PROMOTING SOME LIFTING INTO NE PA AND ITS LOWER LEVEL AGEO
FORCING WAS ALSO PUSH THE FRNT SOUTHWARD. BEST SHOT OF A FEW SHRA
AND EVEN A LITTLE TSRA WILL BE MAINLY ACRS OUR FAR SE FORECAST
AREA IN THE POCONOS TO SRN CATSKILLS FOR THE REST OF THE
AFTERNOON DUE TO THIS DYNAMICAL FORCING. NORTH OF THE FRNT...THE
CUMULUS WAS BUILDING BUT NOT TO EXTENT THAT I EARLIER THHOUGHT.
THE ONLY EXCEPTION WAS OVER AREAS DIRECTLY DOWNWIND OF LAKE
ONTARIO WHERE LAKE MOISTURE WAS ENHANCING LL MOISTURE AND LEADING
TO DEEPER CUMULUS AND A LITTLE ISLD SHRA ACVTY AT TIMES. HENCE
HAVE SOME ISLD CHC OF SHRA WELL N OF THE FRNT ACRS CNTRL NY AND
NRN PA. THIS ACVTY WILL WANE SOON EXCEPT IN NC NY DOWNWIND OF LAKE
ONTARIO.
FOR TONIGHT...INITIALLY CUMULUS AND ISLD SHRA WILL FALL APART WITH
LOSS OF INSOLATION. CONTINUED LL NW FLOW AND CAA WILL CONT ACRS
THE RELATIVELY WARM WATERS OF LAKE ONTARIO. LAKE ONTARIO TEMPS
WERE RUNNING ARND 20-21C AS 850 MB TEMPS DROP TO ARND 7-8C OR SO BY
LATE TONIGHT. ADDTNLY ANOTHER SHRT WAVE WILL DROP SOUTHWARD
OVERNIGHT REACHING SOUTHEAST ONTARIO AND WESTERN QUEBEC BY 12Z.
LIFTING FROM THIS WAVE IN ASSCTN WITH LAKE MOISTURE WILL TRIGGER
SHRA AGAIN LATER TONIGHT IN NC NY...WITH NO PRECIPITATION EXPECTED
IN SC NY DOWN TO NE PA BEFORE 12Z.
THEN FOR SUNDAY...UPPER LEVEL WAVE PASSES TO THE EAST BUT IS
FOLLOWING BY AN EVEN CHILLIER SHOT OF AIR WITH 850 MB TEMPS
DROPPING TO ARND 6C WHICH IS ABT A 14-15C DIFFERENTIAL. THE FLOW
REMAINS ABT 310 OR SO WHICH WILL BRING LAKE MOISTURE DOWN INTO THE
HILLS OF NC NY AND DOWN TO SC NY AND FAR NE PA. WITH INSOLATION
AND COLD TEMPERATURES AT 850 MB I SEE ISLD TO SCT SHRA FROM NRN PA
TO SC NY AND SCT SHRA INTO NC NY DIRECTLY DOWNWIND OF LAKE
ONTARIO. THE ACVTY WILL WANE LATER IN THE DAY AS INSOLATION BREAKS
UP ANY ORGANIZED LAKE EFFECT RAINS. HAVE SLGHT CHC IN NE PA TO LO
CHC IN SC NY TO HIGH CHC IN NC NY FOR SUNDAY.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
HIGH PRESSURE WILL BUILD OVER THE REGION SUNDAY NIGHT AND CROSS
THE REGION MONDAY AND MONDAY NIGHT WITH FAIR WEATHER. WITH LIGHT
WINDS I EXPECT PLENTY OF VALLEY FOG LATE SUNDAY NIGHT AND LATE
MONDAY NIGHT. FOR TUESDAY A WARM FRONT AND SOUTHERLY RETURN FLOW
WILL LIKELY SPREAD A FEW SHRA INTO NE PA AND C NY. THE
CMC...EURO...GFS AND NAM ALL INDICATE TO VARYING DEGREES THAT
THERE WILL BE ENUF MOISTURE ADVECTION FOR SOME PATCHY SHRA ACTVY.
I WENT SLGHT CHC FOR NOW FOR SHRA. OTHERWISE...FAIRLY QUIET ON
TUESDAY AND A LITTLE MILDER.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
RISING HGTS ON TUE WILL RESULT IN SOME INCRSG CLDS BUT SHWRS SHD
BE LIMITED DUE TO STUBBORN LL DRY AIR. YET ANOTHER DIGGING LOW
APCHS FOR WED AND THU AND PUSHES A SFC BNDRY THRU THE AREA. GOOD
GULF CONNECTIONS SHD LEAD TO GOOD CVRG OF SHWRS AND TRWS LATE WED
INTO THU AHD OF THE TROF. DRIER AND COOLER AIR RETURNS ON FRI BHD
THE FNT. ATTM IT LOOKS DRY BHD THE FNT BUT EVENTUALLY THE LWRG
HGTS WITH THE LRG UA LOW WILL RESULT IN MAINLY AFTN CONV.
TEMPS WILL CONT TO AVG WELL BLO SEASONAL NORMS THRU THE PD. MEX
GUID WAS RUNNING A BIT HIER THRU THE PD THAN HPC BUT SEEMED LIKE
THE COOLER EURO HAD A BETTER HANDLE ON THE UA LOW SO MORE CLOSELY
FLWD HPC GUID.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
130 AM EDT UPDATE...
A COLD FRONT WILL MOVE ACROSS THE REGION LATE TONIGHT AND SCATTERED
SHOWERS WILL DEVELOP IN ITS WAKE. BEHIND THE COLD FRONT MVFR CIGS
AND GUSTY WINDS WILL DEVELOP AND ARE EXPECTED TO PREVAIL THROUGH
MID DAY SUNDAY FOR MUCH OF THE AREA. SHOWERS ARE EXPECTED TO
CONTINUE THROUGH THE AFTERNOON AS WELL. MVFR CIGS WILL START TO
LIFT TO VFR BY EARLY EVENING OVER NORTHEAST PENNSYLVANIA. VFR
CONDITIONS WILL MOVE WESTWARD AS THE EVENING HOURS PROGRESS. AFTER
SUNSET WINDS WILL BECOME LIGHT AND VARIABLE WITH SCATTERED TO FEW
CLOUDS.
MON THRU WED...MAINLY VFR.
THU...MVFR IN SHRA AND TSRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJP
NEAR TERM...DJN/DJP
SHORT TERM...DJN
LONG TERM...DGM
AVIATION...KAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
919 PM EDT MON AUG 5 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO SLOWLY SHIFT FURTHER OFFSHORE
TONIGHT. A MOIST SOUTHERLY LOW LEVEL RETURN FLOW WILL PREVAIL
THROUGH MID TO LATE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 915 PM MONDAY...
TONIGHT:
SURFACE HIGH PRESSURE HAS SHIFTED JUST OFF THE SOUTHERN MID-ATLANTIC
COAST THIS EVENING... WHILE THE MID/UPPER LEVEL FLOW ALOFT CONTINUES
TO BE OUT OF THE NORTHWEST. THIS HAS RESULTED IN A LIGHT
SOUTH/SOUTHEASTERLY SURFACE/LOW LEVEL RETURN FLOW UP AND INTO THE
HIGHER TERRAIN ALONG WITH WEAK PERTURBATION MOVING THROUGH THE
NORTHWEST FLOW ALOFT... WHICH HAS ALLOWED SOME SHOWERS TO DEVELOP IN
THE HIGHER TERRAIN. THESE SHOWERS (AND PERHAPS A THUNDERSTORM OR
TWO) HAVE HAD A HARD TIME COMING OFF THE HIGHER TERRAIN AND INTO THE
PIEDMONT. HOWEVER... THE LATEST HRRR AND SOME OF THE OTHER HI-RES
GUIDANCE IS NOW SHOWING THIS ACTIVITY SLOWLY SHIFTING EASTWARD AND
INTO THE PIEDMONT LATER THIS EVENING INTO THE OVERNIGHT HOURS. GIVEN
THE RATHER WEAK INSTABILITY EXPECTED OVER OUR AREA... WE DO NOT
ANTICIPATE ANY SVR WEATHER FROM THIS ACTIVITY. HOWEVER... WE COULD
SEE A BRIEF HEAVY DOWNPOUR AND REDUCED VISIBILITY AS A SHOWER AND/OR
STORM MOVES ACROSS A GIVEN LOCATION. THE HIGHEST PROBABILITIES WILL
REMAIN ACROSS THE NORTH/NORTHWESTERN PIEDMONT THIS EVENING/TONIGHT.
THUS... WILL CONTINUE TO SHOW THE FAR NORTHWEST PIEDMONT WITH THE
HIGHEST POPS AFTER MIDNIGHT (CHANCE... 25-40 PERCENT) TO SLIGHT
CHANCE JUST WEST OF RALEIGH. GIVEN THIS EXPECT SKIES WILL GENERALLY
BE PARTLY TO MOSTLY CLOUDY/CLOUDY OVERNIGHT... WHICH WILL HELP TO
KEEP TEMPS UP A BIT TONIGHT... ALONG WITH THE INCREASE IN LOW LEVEL
MOISTURE. THUS... EXPECT LOWS TO RANGE FROM THE MID 60S EAST TO
UPPER 60S WEST. -BSD
TUESDAY:
EXPECT AN INCREASING POTENTIAL FOR SHOWER (THUNDERSTORM) ACTIVITY
TUESDAY MORNING (AFTERNOON) AS A SEASONABLY MOIST SOUTHERLY
LOW-LEVEL RETURN FLOW AIDS IN MARGINAL TO MODERATE DIURNAL
DESTABILIZATION IN THE PRESENCE OF WEAK LOW-LEVEL CONVERGENCE AND AN
INCREASED POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN NW FLOW
ALOFT. WILL INDICATE PRECIP CHANCES RANGING FROM 20-50%...HIGHEST IN
THE WESTERN PIEDMONT AND LOWEST IN THE COASTAL PLAIN WHERE LOW-LEVEL
MOISTURE /DIURNAL DESTABILIZATION/ IS EXPECTED TO BE MARGINAL. HIGHS
WILL BE SIMILAR TO TODAY AND PRIMARILY DEPEND ON CLOUD COVER...
RANGING FROM NEAR 80F IN THE N/NW PIEDMONT TO MID/UPPER 80S IN THE
SANDHILLS AND COASTAL PLAIN. -VINCENT
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 318 PM MONDAY...
TUESDAY NIGHT...APPROACH OF A WEAK MID-UPPER LEVEL DISTURBANCE
COUPLED WITH AN INCREASINGLY MOIST AIR MASS WILL SUPPORT THE
POTENTIAL FOR A FEW SHOWERS/ISOLATED THUNDER WELL INTO THE
NIGHT...MAINLY OVER THE NW PIEDMONT. INCREASING/THICKENING CLOUD
COVER AND A LIGHT SLY WIND WILL RESULT IN A FAIRLY UNIFORM TEMP
FIELD OVERNIGHT. MIN TEMPS UPPER 60S TO AROUND 70.
WEDNESDAY AND WEDNESDAY NIGHT...THE MID-UPPER LEVEL TROUGH TRANSLATE
SLOWLY EWD TOWARD AND ACROSS THE MID ATLANTIC AND CAROLINAS WED
AFTERNOON-EVENING. 12Z GFS NOT TOO IMPRESSIVE WITH ITS CONVECTIVE
PARAMETERS WED AFTERNOON-EVENING ...DEPICTING MARGINAL/SLIGHT
INSTABILITY AT BEST. STILL...FAVORED LOW LEVEL CONFLUENCE OVER THE
WESTERN PIEDMONT DURING PRIME HEATING SUPPORT HIGH CHANCE POP IN
THIS REGION....WITH POPS TAPERING TO SLIGHT CHANCE OVER THE SOUTHERN
COASTAL PLAINS AND SANDHILLS. MORE CLOUDS THAN SUN WILL LIMIT NORMAL
DIURNAL TEMP RISE IN THE WEST-NW WHERE MAX TEMPS EXPECTED TO BE
LOWER 80S. PARTIAL SUN OVER THE SE HALF SHOULD WARM TEMPS WELL INTO
THE 80S. CONSIDERABLE CLOUDINESS WEDNESDAY NIGHT WILL MAINTAIN HUMID
CONDITIONS. MIN TEMPS AROUND 70/LOWER 70S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 318 PM MONDAY...
THURSDAY...
LINGERING MID-UPPER LEVEL TROUGH WILL MAINTAIN A DECENT THREAT FOR
SCATTERED SHOWERS AND THUNDERSTORMS THURSDAY AS LOW LEVEL
CONVERGENCE PROJECTED TO BE MAXIMIZED OVER OUR REGION. ONLY CAVEAT
IS THAT BUILDING MID-UPPER LEVEL HEIGHTS MAY RESULT IN THE
DEVELOPMENT OF A LAYER OF WARM AIR ALOFT...POSSIBLY CAPPING AIR MASS
AND LIMITING CONVECTIVE DEVELOPMENT. HOWEVER CONSIDERING THE AMOUNT
OF LOW LEVEL CONVERGENCE AND AVAILABLE MOISTURE SUPPORT CHANCE POPS
THURSDAY.
FRIDAY-SATURDAY....SUB TROPICAL RIDGE PROJECTED TO EXPAND/STRENGTHEN
WEST-TO-EAST ACROSS THE LOWER MS VALLEY AND SE U.S. THIS WILL PLACE
CENTRAL NC ON THE PERIPHERY OF THIS WEATHER SYSTEM. WEAK
PERTURBATIONS TRAVERSING EWD COUPLED WITH AVAILABLE MOISTURE AND
INSTABILITY SUGGEST A THREAT FOR SCATTERED SHOWERS AND STORMS EACH
DAY...MORE SO ON SATURDAY AFTERNOON AS A S/W IN THE NORTHERN STREAM
PROPELS A SFC FRONT SWD TOWARD CENTRAL NC. PLAN TO HAVE
CHANCE-SLIGHT CHANCE POPS NW-SE ACROSS THE REGION FRIDAY WITH HIGH
CHANCE POPS MOST LOCATIONS LATE SATURDAY-SATURDAY NIGHT.
SUNDAY INTO MONDAY....LATEST GFS HAS TRENDED TOWARD THE MORE
PROGRESSIVE ECMWF WHICH PUSHES THE SFC COLD FRONT SWD ACROSS CENTRAL
NC SUNDAY...AND POSITIONED SOUTH OF THE REGION MONDAY. THIS SUGGEST
A DECREASING THREAT FOR SCATTERED SHOWERS AND STORMS. PLAN TO
MAINTAIN MENTION OF A SMALL CHANCE BOTH DAYS...SUNDAY TO ACCOUNT FOR
POSSIBLE MODEL TIMING ISSUES WITH THE FRONTAL PASSAGE...AND ON
MONDAY AS DEVELOPING NW FLOW ALOFT MAY PROVIDE AN AVENUE FOR
DISTURBANCES ROTATING AROUND A DEEP CLOSED UPPER LOW OVER THE
NORTHERN LAKES TO TRANSLATE INTO OUR REGION.
TEMPS THURSDAY THROUGH MONDAY DEPENDENT UPON EXTENT OF CLOUD COVER
AND AREAL COVERAGE OF CONVECTION. EXPECT AFTERNOON TEMPS TO AVERAGE
A COUPLE OF DEGREES BELOW NORMAL WHILE OVERNIGHT TEMPS WILL BE 3-5
DEGREES ABOVE NORMAL.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 745 PM MONDAY...
24 HOUR TAF PERIOD: A FEW SHOWERS POPPING UP ON RADAR AND SHOWN BY
HIGH RESOLUTION MODEL RUNS SHOULD REACH THE TRIAD OVER THE NEXT
COUPLE OF HOURS. WILL AMEND THE TAFS AS NEEDED. SOUNDINGS INDICATE
VERY DRY LOW LEVELS HOWEVER AND CEILINGS ARE NOT EXPECTED TO DROP TO
MVFR UNTIL 15Z. THE AFOREMENTIONED SHOWERS MAY HAMPER THAT THEORY IN
LOCALIZED AREAS IF THE LOW LEVELS MOISTEN ENOUGH THERE COULD BE
SUB-VFR CONDITIONS BEFORE 15Z. EAST OF THE TRIAD CONDITIONS WILL
REMAIN DRY OVERNIGHT BUT POTENTIAL SHOWERS WILL SPREAD SLOWLY
EASTWARD BY MORNING AND INTO THE AFTERNOON BRINGING POTENTIAL FOR
SHOWERS AT ALL TERMINALS LATE IN THE TAF PERIOD WITH THE GREATEST
THREAT STILL ACROSS THE WEST.
LONG TERM: AS HIGH PRESSURE MOVES OFFSHORE...CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL INCREASE EACH DAY THROUGH MIDWEEK LEADING UP TO A
PERIOD OF MORE UNSETTLED WEATHER BY THURSDAY WHEN A NEW FRONTAL
SYSTEM WILL MOVE IN FROM THE NORTHWEST.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD
NEAR TERM...BSD/VINCENT
SHORT TERM..WSS
LONG TERM...WSS
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
743 PM EDT MON AUG 5 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC WILL MOVE OFFSHORE
TONIGHT. A MOIST SOUTHERLY LOW LEVEL RETURN FLOW WILL PREVAIL
THROUGH MID TO LATE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 300 PM MONDAY...
OVERVIEW:
SYNOPTIC SUBSIDENCE /HEIGHT RISES/ OVER THE MID-ATLANTIC THIS
MORNING WILL WANE AND SHIFT TO NEW ENGLAND THIS AFT/TONIGHT AS AN
UPPER LEVEL TROUGH PROGRESSES FURTHER NORTHEAST INTO THE CANADIAN
MARITIMES. ACCORDINGLY...1021 MB SFC HIGH PRESSURE CENTERED OVER THE
MID-ATLANTIC THIS MORNING WILL WEAKEN AND SHIFT OFFSHORE THE MID-
ATLANTIC COAST. AS THE SFC HIGH PROGRESSES EASTWARD AND A LIGHT S/SE
RETURN FLOW DEVELOPS OVER THE WESTERN CAROLINAS THIS AFT/EVE...A
STATIONARY FRONT EXTENDING EASTWARD FROM NORTHERN GA INTO
CENTRAL/UPSTATE SC WILL BEGIN TO LIFT NORTH FROM UPSTATE SC INTO
WESTERN NC (ALONG AND WEST OF I-77)...WITH MOISTURE SLOWLY
INCREASING TONIGHT ALONG AND WEST OF THE HIGHWAY 1 CORRIDOR.
TONIGHT:
GIVEN THE AFOREMENTIONED MOISTURE IN ADDITION TO SEASONABLY WEAK
MID-LEVEL LAPSE RATES...DIURNAL DESTABILIZATION TODAY WILL BE
MARGINAL AND LARGELY CONFINED TO WESTERN PORTIONS OF THE STATE WHERE
LOW-LEVEL CONVERGENCE /MOISTURE POOLING/ AND THE SLOW NORTHWARD
RETREAT OF THE FRONT WILL CONTRIBUTE TO PERHAPS 250-500 J/KG MLCAPE.
GRADUAL LOW-LEVEL MOISTURE RETURN OVERNIGHT WILL RESULT IN A SLOW
INCREASE IN MUCAPE...PERHAPS UP TO 500 J/KG IN THE WESTERN PIEDMONT
AND 1000 J/KG IN THE FOOTHILLS/MOUNTAINS BY 12Z TUE MORNING. FORCING
FOR ASCENT WILL BE CONFINED TO WEAK/SHALLOW LOW-LEVEL CONVERGENCE
AND UPSLOPE FLOW IN WESTERN NC THIS AFTERNOON INTO TONIGHT. ALTHOUGH
THERE IS AT LEAST A POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN
W/NW FLOW ALOFT THROUGH TONIGHT...19Z WV IMAGERY AND RAP DATA DO NOT
SUGGEST ANY SIGNIFICANT DPVA WILL BE PRESENT. PER 19Z VIS SAT/RADAR
IMAGERY INDICATING SHALLOW AGITATED CU AND A FEW BRIEF SHOWERS IN
THE WEST...WILL INDICATE A SLIGHT CHANCE OF SHOWERS THROUGH THIS
EVENING. INCREASINGLY MOIST LOW-LEVEL UPSLOPE FLOW AND A RELATIVELY
BETTER CHANCE FOR SMALL AMPLITUDE DISTURBANCES ALOFT SHOULD RESULT
IN A BETTER CHANCE FOR ISOLD/SCT SHOWERS IN THE WESTERN PIEDMONT
PRIOR TO SUNRISE TUE...SUPPORTED BY THE LATEST HIGH-RES CONVECTION
ALLOWING MODELS. WILL INDICATE INCREASING PRECIP CHANCES. EXPECT
LOWS TONIGHT NEAR OR SLIGHTLY BELOW NORMAL...IN THE LOWER TO UPPER
60S...WARMEST IN THE WEST/SW PIEDMONT WHERE MORE CLOUD COVER AND
BETTER LOW-LEVEL MOISTURE WILL BE PRESENT AND COOLEST IN THE TYPICAL
AREAS OF THE NORTHERN PIEDMONT AND NE COASTAL PLAIN WHERE A DRIER
AIRMASS AND LESS CLOUD COVER (AT LEAST INITIALLY) WILL PREVAIL.
TUESDAY:
EXPECT AN INCREASING POTENTIAL FOR SHOWER (THUNDERSTORM) ACTIVITY
TUESDAY MORNING (AFTERNOON) AS A SEASONABLY MOIST SOUTHERLY
LOW-LEVEL RETURN FLOW AIDS IN MARGINAL TO MODERATE DIURNAL
DESTABILIZATION IN THE PRESENCE OF WEAK LOW-LEVEL CONVERGENCE AND AN
INCREASED POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN NW FLOW
ALOFT. WILL INDICATE PRECIP CHANCES RANGING FROM 20-50%...HIGHEST IN
THE WESTERN PIEDMONT AND LOWEST IN THE COASTAL PLAIN WHERE LOW-LEVEL
MOISTURE /DIURNAL DESTABILIZATION/ IS EXPECTED TO BE MARGINAL. HIGHS
WILL BE SIMILAR TO TODAY AND PRIMARILY DEPEND ON CLOUD COVER...
RANGING FROM NEAR 80F IN THE N/NW PIEDMONT TO MID/UPPER 80S IN THE
SANDHILLS AND COASTAL PLAIN. -VINCENT
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 318 PM MONDAY...
TUESDAY NIGHT...APPROACH OF A WEAK MID-UPPER LEVEL DISTURBANCE
COUPLED WITH AN INCREASINGLY MOIST AIR MASS WILL SUPPORT THE
POTENTIAL FOR A FEW SHOWERS/ISOLATED THUNDER WELL INTO THE
NIGHT...MAINLY OVER THE NW PIEDMONT. INCREASING/THICKENING CLOUD
COVER AND A LIGHT SLY WIND WILL RESULT IN A FAIRLY UNIFORM TEMP
FIELD OVERNIGHT. MIN TEMPS UPPER 60S TO AROUND 70.
WEDNESDAY AND WEDNESDAY NIGHT...THE MID-UPPER LEVEL TROUGH TRANSLATE
SLOWLY EWD TOWARD AND ACROSS THE MID ATLANTIC AND CAROLINAS WED
AFTERNOON-EVENING. 12Z GFS NOT TOO IMPRESSIVE WITH ITS CONVECTIVE
PARAMETERS WED AFTERNOON-EVENING ...DEPICTING MARGINAL/SLIGHT
INSTABILITY AT BEST. STILL...FAVORED LOW LEVEL CONFLUENCE OVER THE
WESTERN PIEDMONT DURING PRIME HEATING SUPPORT HIGH CHANCE POP IN
THIS REGION....WITH POPS TAPERING TO SLIGHT CHANCE OVER THE SOUTHERN
COASTAL PLAINS AND SANDHILLS. MORE CLOUDS THAN SUN WILL LIMIT NORMAL
DIURNAL TEMP RISE IN THE WEST-NW WHERE MAX TEMPS EXPECTED TO BE
LOWER 80S. PARTIAL SUN OVER THE SE HALF SHOULD WARM TEMPS WELL INTO
THE 80S. CONSIDERABLE CLOUDINESS WEDNESDAY NIGHT WILL MAINTAIN HUMID
CONDITIONS. MIN TEMPS AROUND 70/LOWER 70S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 318 PM MONDAY...
THURSDAY...
LINGERING MID-UPPER LEVEL TROUGH WILL MAINTAIN A DECENT THREAT FOR
SCATTERED SHOWERS AND THUNDERSTORMS THURSDAY AS LOW LEVEL
CONVERGENCE PROJECTED TO BE MAXIMIZED OVER OUR REGION. ONLY CAVEAT
IS THAT BUILDING MID-UPPER LEVEL HEIGHTS MAY RESULT IN THE
DEVELOPMENT OF A LAYER OF WARM AIR ALOFT...POSSIBLY CAPPING AIR MASS
AND LIMITING CONVECTIVE DEVELOPMENT. HOWEVER CONSIDERING THE AMOUNT
OF LOW LEVEL CONVERGENCE AND AVAILABLE MOISTURE SUPPORT CHANCE POPS
THURSDAY.
FRIDAY-SATURDAY....SUB TROPICAL RIDGE PROJECTED TO EXPAND/STRENGTHEN
WEST-TO-EAST ACROSS THE LOWER MS VALLEY AND SE U.S. THIS WILL PLACE
CENTRAL NC ON THE PERIPHERY OF THIS WEATHER SYSTEM. WEAK
PERTURBATIONS TRAVERSING EWD COUPLED WITH AVAILABLE MOISTURE AND
INSTABILITY SUGGEST A THREAT FOR SCATTERED SHOWERS AND STORMS EACH
DAY...MORE SO ON SATURDAY AFTERNOON AS A S/W IN THE NORTHERN STREAM
PROPELS A SFC FRONT SWD TOWARD CENTRAL NC. PLAN TO HAVE
CHANCE-SLIGHT CHANCE POPS NW-SE ACROSS THE REGION FRIDAY WITH HIGH
CHANCE POPS MOST LOCATIONS LATE SATURDAY-SATURDAY NIGHT.
SUNDAY INTO MONDAY....LATEST GFS HAS TRENDED TOWARD THE MORE
PROGRESSIVE ECMWF WHICH PUSHES THE SFC COLD FRONT SWD ACROSS CENTRAL
NC SUNDAY...AND POSITIONED SOUTH OF THE REGION MONDAY. THIS SUGGEST
A DECREASING THREAT FOR SCATTERED SHOWERS AND STORMS. PLAN TO
MAINTAIN MENTION OF A SMALL CHANCE BOTH DAYS...SUNDAY TO ACCOUNT FOR
POSSIBLE MODEL TIMING ISSUES WITH THE FRONTAL PASSAGE...AND ON
MONDAY AS DEVELOPING NW FLOW ALOFT MAY PROVIDE AN AVENUE FOR
DISTURBANCES ROTATING AROUND A DEEP CLOSED UPPER LOW OVER THE
NORTHERN LAKES TO TRANSLATE INTO OUR REGION.
TEMPS THURSDAY THROUGH MONDAY DEPENDENT UPON EXTENT OF CLOUD COVER
AND AREAL COVERAGE OF CONVECTION. EXPECT AFTERNOON TEMPS TO AVERAGE
A COUPLE OF DEGREES BELOW NORMAL WHILE OVERNIGHT TEMPS WILL BE 3-5
DEGREES ABOVE NORMAL.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 745 PM MONDAY...
24 HOUR TAF PERIOD: A FEW SHOWERS POPPING UP ON RADAR AND SHOWN BY
HIGH RESOLUTION MODEL RUNS SHOULD REACH THE TRIAD OVER THE NEXT
COUPLE OF HOURS. WILL AMEND THE TAFS AS NEEDED. SOUNDINGS INDICATE
VERY DRY LOW LEVELS HOWEVER AND CEILINGS ARE NOT EXPECTED TO DROP TO
MVFR UNTIL 15Z. THE AFOREMENTIONED SHOWERS MAY HAMPER THAT THEORY IN
LOCALIZED AREAS IF THE LOW LEVELS MOISTEN ENOUGH THERE COULD BE
SUB-VFR CONDITIONS BEFORE 15Z. EAST OF THE TRIAD CONDITIONS WILL
REMAIN DRY OVERNIGHT BUT POTENTIAL SHOWERS WILL SPREAD SLOWLY
EASTWARD BY MORNING AND INTO THE AFTERNOON BRINGING POTENTIAL FOR
SHOWERS AT ALL TERMINALS LATE IN THE TAF PERIOD WITH THE GREATEST
THREAT STILL ACROSS THE WEST.
LONG TERM: AS HIGH PRESSURE MOVES OFFSHORE...CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL INCREASE EACH DAY THROUGH MIDWEEK LEADING UP TO A
PERIOD OF MORE UNSETTLED WEATHER BY THURSDAY WHEN A NEW FRONTAL
SYSTEM WILL MOVE IN FROM THE NORTHWEST.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM..WSS
LONG TERM...WSS
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
658 PM CDT MON AUG 5 2013
.UPDATE...
ISSUED AT 651 PM CDT MON AUG 5 2013
LAST OF THE REMAINING STRATOCU BURNING OFF IN THE PARK RAPIDS
AREA. REMAINDER OF THE FCST AREA CLEAR TO PARTLY CLOUDY WITH LIGHT
WINDS AS WK HIGH PRESSURE RIDGE IS OVERHEAD. POTENT SHORT WAVE
IN SW SASK PRODUCING SCT TSTMS IN SRN SK AND ERN MT WILL CONTINUE
TO MOVE EAST OVERNIGHT WITH LATEST RAP INDICATING SHORTWAVE IN THE
RED RIVER VALLEY BY 13Z. THIS SEEMS REASONABLE AND BASED ON LATEST
HRRR MODEL PRECIP IDEA OF SCT CONVECTION ENTERING NW FCST AREA
AFTER 06Z AND SPREADING INTO AT LEAST THE NRN VALLEY AND FAR NW MN
AROUND 10-13Z SEEMS VERY REASONABLE. HOWEVER INSTABILITY VALUES
WEAKEN BY 12Z SO PROBABLY MORE OF A SHOWER AND ISOLD THUNDER EVENT
FOR NRN VALLEY. ALSO WONDER TOO IF COVERAGE VIA HRRR IS TOO MUCH
GIVEN UPSTREAM COVERAGE OF STORMS AIDED BY SFC HEATING. STILL IDEA
OF SPREADING LIKELY POPS EAST LATER TONIGHT INTO TUESDAY MORNING
DOES SEEM REASONABLE AND WILL MAINTAIN.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 321 PM CDT MON AUG 5 2013
WITH THE CLOUDS CONTINUING TO PUSH EAST SLOWLY ANY CLEARING WILL
BE RELATIVELY SHORT LIVED. CONVECTION STARTING UP OVER EASTERN MT
WILL BEGIN SPREADING IN SOME HIGHER LEVEL CLOUDS TONIGHT. THE MAIN
FORECAST CONCERN WILL SHIFT BACK TO TIMING THE NEXT CHANCE OF PCPN
FOR LATER TONIGHT INTO TUE/TUE NIGHT. TRIED TO FOLLOW THE HIGH RES
MODELS FOR THE ARRIVAL TIME OF PCPN TONIGHT AND THEN KIND OF A
BLEND FOR TIMING THE BEST CHANCES FROM WEST TO EAST THRU TUE. SPC
HAS SOUTHWEST ND AND WESTERN SD IN A SLIGHT RISK FOR DAY1. THIS IS
THE AREA ONCE AGAIN WHICH HAS HEATED OUT WITH SLIGHTLY HIGHER DEW
POINTS. RESULTANT MLCAPE VALUES ARE PUSHING TO AROUND 1500J/KG
WITH DECENT SHEAR ALSO PRESENT. SO ONCE AGAIN THE CONVECTION IS
FIRING WEST OF THE FA. THE NEXT DECENT UPSTREAM SHORT WAVE IS
DROPPING INTO NORTHWEST MT. THIS WAVE WILL BEGIN AN EASTWARD
SHIFT TAKING IT INTO EASTERN MT/WESTERN ND BY 06Z THEN CENTRAL ND
BY 12Z. THEREFORE IT SEEMS REASONABLE THAT SOME LINGERING
CONVECTION THAT FIRES OUT WEST MAY HOLD TOGETHER AS IT TRACKS INTO
THE FA LATE. ANOTHER AREA THAT WILL BEAR WATCHING IS A COLD FRONT
UP IN THE MANITOBA LAKES REGION NORTH OF WINNIPEG. AS THE WESTERN
WAVE APPROACHES CENTRAL ND BY 12Z TUE IT WILL HELP ORGANIZE A WEAK
SFC LOW IN THIS SAME GENERAL VICINITY. THE COLD FRONT SHOULD GET
DRAWN DOWN INTO THE NORTHERN FA BY 12Z. THE HIGH RES MODELS SHOW
THE POTENTIAL FOR SOME PCPN ALONG THIS BOUNDARY TOO. SOME WEAK
WARM ADVECTION AND LOW LEVEL JET ENERGY MAY ALSO COME INTO PLAY
AFTER DARK TOO...FEEDING INTO CENTRAL ND IN THE LATE EVENING.
ALL OF THE ABOVE MENTIONED FEATURES KIND OF MELD OVER THE FA ON
TUE WITH THE COLD FRONT SLOWLY SLIDING FROM NORTH TO SOUTH AND THE
SHORT WAVE FROM WEST TO EAST. KEPT LIKELY CHANCES FOR PCPN AND
TRIED TO BREAK THEM OUT TO SHOW THE WEST TO EAST PROGRESS THRU THE
DAY. SPC DAY2 HAS A SLIGHT RISK JUST TO THE SOUTH OF THE FA SO HOW
FAST THE FRONT DROPS SOUTH WILL LIKELY DETERMINE IF ANY TSTMS CAN
BECOME STRONG TO SEVERE ACROSS THE FAR SOUTH TUE AFTERNOON. STILL
EXPECT ANY LINGERING PCPN TO EXIT THE EAST TUE EVENING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 321 PM CDT MON AUG 5 2013
KEPT WED PCPN FREE WITH THE NEXT PCPN CHANCES COMING WED NIGHT
INTO THU. PRETTY MUCH LEFT THE PCPN CHANCES FOR THIS NEXT EVENT AS
IS FOR NOW.
FRIDAY TO MONDAY...MODEL AGREEMENT CONTINUES WITH THE SAME OLD
PATTERN OF CONFLUENT NW FLOW AT 500MB...WHICH MEANS DRY AND
SLIGHTLY COOLER THAN NORMAL FOR THE NORTHERN PLAINS. THERE REMAINS
A CHANCE FOR SOME SHOWER ACTIVITY AT SOME POINT OVER THE NEXT
WEEKEND BUT WITH UNCERTAINTY IN TIMING AND SMALL AREAL COVERAGE
THAT A WEAK WAVE MAY INDUCED PRECIP...HAVE KEPT THE MAJORITY OF
THE CWFA COMPLETELY DRY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 651 PM CDT MON AUG 5 2013
REMAINING STRATOCU IN BJI-PKD AREAS WILL SCATTER OUT LEAVING VFR
CONDITIONS AREA WIDE THROUGH 08Z WITH SOME INCREASE IN HIGH CLOUDS
INTO DVL LATER THIS EVE. SHORTWAVE WILL SPREAD SCT THUNDERSTORMS
INTO DVL REGION 08Z-12Z...BUT WITH WEAKER INSTABILITY PUT MORE
SHOWERY PRECIP AS PREDOMINATE VS THUNDER AT REST OF THE TAF SITES
TUESDAY. WINDS WILL TURN NORTHERLY BY MID TO LATE MORNING IN NE
ND AND THEN SPREAD SOUTH REACHING SOUTHERN FCST AREA MID AFTN. AT
THE PRESENT TIME KEPT CIGS WITH ANY PRECIP IN THE 5000 FT
RANGE...THOUGH COULD BE AREAS OF MVFR CIGS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...GODON
LONG TERM...GODON/JK
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
330 PM CDT SUN AUG 4 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 330 PM CDT SUN AUG 4 2013
MAIN FORECAST PROBLEM IN THE SHORT TERM PERIOD IS THE CHANCE OF
SHOWERS AND THUNDERSTORMS LATE THIS AFTERNOON AND TONIGHT. MODELS
HAVE BEEN HAVING A HARD TIME FIGURING OUT WHAT WILL TRANSPIRE LATE
THIS AFTERNOON INTO THIS EVENING. MANY FAVORABLE FACTORS FOR
CONVECTION ARE IN PLACE. STRONG UPPER LEVEL JET IS PROVIDING GOOD
BULK SHEAR WITH INDIVIDUAL IMPULSES TRACKING ACROSS NORTHEAST
MONTANA AND SOUTHERN SASKATCHEWAN. DEWPOINT HAVE CLIMBED INTO THE
UPPER 50S TO LOWER 60S ACROSS THE AREA WITH AN INVERTED SURFACE
TROUGH TRACKING SLOWLY EAST ACROSS WESTERN NORTH DAKOTA PROVIDING
AN ADDITIONAL FOCUSING MECHANISM FOR CONVECTION. THE LIMITING
FACTOR HAS BEEN THE EXTENSIVE CLOUD COVER PROVIDING MEAGER LOW
LEVEL LAPSE RATES. 19Z KDIK LAPS SOUNDING STILL INDICATES AROUND
100 MB OF CIN TO BE OVERCOME. HOWEVER SKIES ARE BEGINNING TO CLEAR
IN EASTERN MONTANA INTO WESTERN NORTH DAKOTA WITH A GOOD 3 HOURS
OF HEATING BEFORE WE PASS OUR DIURNAL MAX AND CURRENTLY 1000-1500
J/KG OF CAPE AVAILABLE OVER FAR WESTERN NORTH DAKOTA. THE
DIRECTIONAL SHEAR PROFILE DOES BECOME LESS FAVORABLE WITH
SIGNIFICANT DRYING ALOFT TAKING PLACE BEHIND THE INVERTED TROUGH
WHICH CURRENTLY LAYS OVER WESTERN NORTH DAKOTA.
MESOSCALE MODELS HAVE BEEN ALL OVER THE PLACE WITH CONVECTION
ACROSS WESTERN AND CENTRAL NORTH DAKOTA. ABOUT THE ONLY TREND THAT
CAN BE SEEN IS THAT SUCCESSIVE RUNS HAVE BECOME LESS AND LESS
OMINOUS FOR CONVECTION DEVELOPING OVER WESTERN OR CENTRAL NORTH
DAKOTA THIS AFTERNOON OR THIS EVENING. WITH THIS SAID...STILL
THINK THERE IS A WINDOW OF OPPORTUNITY FOR CONVECTION OVER CENTRAL
NORTH DAKOTA LATE THIS AFTERNOON THROUGH LATE EVENING. THE 18Z RAP
SHOWS CONVECTION TRYING TO DEVELOP OVER THE NORTH CENTRAL LATE
THIS AFTERNOON...SPREADING SOUTHWEST INTO SOUTHWEST NORTH DAKOTA
EARLY THIS EVENING. BUT THE STRONGEST CONVECTION REMAIN OVER THE
NORTH CENTRAL INTO EASTERN NORTH DAKOTA...CLOSEST TO THE MID LEVEL
SHORTWAVE TROUGH. THE 12Z WRF DID NOT HAVE A GOOD HANDLE ON
CONVECTION ACROSS THE NORTH...BUT DOES DEVELOP A LINE OF
CONVECTION ACROSS THE SOUTHWEST BETWEEN 21-22Z. EACH SUCCESSIVE
RUN OF THE HRRR CONTINUES DEPICT WEAKER CONVECTION DEVELOPING OVER
CENTRAL AND EASTERN NORTH DAKOTA THIS EVENING.
SETTLED ON A 20-30 POPS OVER THE CENTRAL INTO THE SOUTHWEST LATE
THIS AFTERNOON SPREADING INTO CENTRAL AND EASTERN NORTH DAKOTA
TONIGHT. WILL NOT MENTION SEVERE WORDING BUT A FEW STRONG TO
POSSIBLY SEVERE CELLS CAN NOT BE RULED OUT GIVEN THE STRONG SHEAR
AND INCREASING CAPE.
CONVECTION...IF IT DOES DEVELOP SHOULD MOVE OUT OF THE EASTERN CWA
AFTER MIDNIGHT. WE THEN GET A PERIOD OF UPPER LEVEL RIDGING MONDAY
AHEAD OF THE NEXT SHORTWAVE TROUGH...AND THE STRONG SHORTWAVE
ASSOCIATED WITH THE RETROGRADING UPPER LEVEL LOW OVER DROPPING
DOWN FROM THE HUDSON BAY.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 PM CDT SUN AUG 4 2013
THE NORTHERN PLAINS WILL BE UNDER NORTHWEST FLOW ALOFT MONDAY
NIGHT WITH UPPER LEVEL RIDGING ACROSS THE SOUTHERN PLAINS AND
DEEP LOW PRESSURE OVER THE WESTERN HUDSON BAY. WILL SEE
INCREASING CHANCES OF SHOWERS/THUNDERSTORMS MONDAY EVENING WEST
AND LATE MONDAY NIGHT THROUGH TUESDAY MORNING AREA WIDE AS A
POTENT EMBEDDED S/WV ROTATES THROUGH THE FLOW AND INTO NORTH
DAKOTA...IN ADDITION TO A SFC TROUGH/COLD FRONTAL BOUNDARY PUSHING
SOUTH ACROSS THE STATE INTO TUESDAY MORNING.
BY TUESDAY AFTERNOON...THE MAIN AREA OF SHOWERS/THUNDERSTORMS
ASSOCIATED WITH THE COLD FRONT WILL HAVE MOVED SOUTH AND EAST OF
CENTRAL NORTH DAKOTA. WILL NEED TO KEEP AN EYE ON THE SOUTHEAST
DURING THE AFTERNOON FOR A STRONGER STORM WHERE MODELS PROJECT
NEAR 1000 J/KG OF CAPE AND LITTLE IF ANY CIN. BY TUESDAY EVENING THE
UPPER LEVEL LOW IS FORECAST TO BE BETWEEN HUDSON BAY AND LAKE
WINNIPEG...MAINTAINING STRONG NORTHWEST FLOW ALOFT THROUGH
THURSDAY (POSSIBLY INTO FRIDAY) WITH THE UPPER LOW REMAINING
QUASI-STATIONARY. LINGERING LOW LEVEL MOISTURE COUPLED WITH
EMBEDDED ENERGY IN THE FLOW ALOFT WILL MAINTAIN SOME CHANCE FOR
DIURNALLY DRIVEN SHOWERS/ISOLATED THUNDERSTORMS BOTH WEDNESDAY AND
THURSDAY.
UPPER LOW PROPAGATES SLOWLY EAST TO OVER ONTARIO FRIDAY INTO
FRIDAY NIGHT...WITH A RIDGE BUILDING INTO THE MONTANA ROCKIES.
HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE DAKOTAS THURSDAY
NIGHT...REMAINING IN PLACE WELL INTO THE WEEKEND. THIS WILL LEAD
TO MAINLY DRY CONDITIONS AND CONTINUED BELOW NORMAL TEMPERATURES
OVER MOST OF THE CWA THROUGH THE REMAINDER OF THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 330 PM CDT SUN AUG 4 2013
MAIN FEATURE FOR THE 18Z TAF PERIOD WAS MVFR CEILINGS MOST AREAS
THROUGH AROUND 21 UTC. THEN A PERIOD OF VCTS LATE AFTERNOON INTO
MID EVENING FOR KDIK...KBIS AND KMOT...AND AFTER 00Z AT KJMS. WITH
KISN CURRENTLY OVER THE INVERTED TROUGH...DID NOT ADD A MENTION OF
VCTS HERE. ALSO BROUGHT A PERIOD OF IFR CEILINGS INTO KJMS AROUND
10Z-16Z MONDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...TWH
LONG TERM...NH
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
152 AM CDT SUN AUG 4 2013
.UPDATE...
ISSUED AT 151 AM CDT SUN AUG 4 2013
UPDATED THE FORECAST TO REMOVE THE SEVERE THUNDERSTORM WATCH FOR
ALL OF SOUTHWESTERN NORTH DAKOTA. ALSO ADJUSTED THE HOURLY POPS TO
HONE IN ON THE AREA OF PRECIPITATION MOVING FROM WEST TO EAST
PRIMARILY SOUTH OF I-94. THE UPDATED GRIDDED AND TEXT PRODUCTS
HAVE BEEN SENT.
UPDATE ISSUED AT 1157 PM CDT SAT AUG 3 2013
UPDATE TO CLEAR GOLDEN VALLEY/BILLINGS FROM SEVERE THUNDERSTORM
WATCH. PER LATEST SWOMCD...MARGINAL SEVERE WEATHER THREAT MAY
PERSIST INTO THE EARLY MORNING AND WILL KEEP REMAINDER OF WATCH
GOING. MADE SOME ADDITIONAL CHANGES TO POPS PER LATEST RADAR TRENDS.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 321 PM CDT SAT AUG 3 2013
MAIN FORECAST PROBLEM IN THE SHORT TERM PERIOD WILL BE
THUNDERSTORM CHANCES.
CURRENTLY...ALTHOUGH NOT REAL WARM...A MOIST UNSTABLE ATMOSPHERE
IS DEVELOPING ACROSS EASTERN MONTANA AND FAR WESTERN NORTH DAKOTA.
A SHORTWAVE INDICATED OVER NORTH CENTRAL MONTANA IN A PROGRESSIVE
BAND OF WESTERLIES HAS INITIATED CONVECTION WEST OF GLASGOW.
EXPECT CONVECTION TO CONTINUE TO INCREASE IN AN AREA OF STEEPENING
LAPSE RATES AND STRONG DEEP LAYER SHEAR. THE 18 UTC HRRR INDICATES
DISCRETE SUPERCELLS TRACKING ACROSS EASTERN MONTANA THIS AFTERNOON
AND EVENING...CLIPPING THE FAR SOUTHWEST LATE THIS EVENING. THE
12 UTC WRF AND HIRES-NMM/ARW ARE SIMILAR BUT MAYBE A BIT LATER AND
TRANSITION FROM DISCRETE CELLS INTO AN MCS THAT TRACKS ACROSS THE
SOUTHWEST AND FAR SOUTH CENTRAL LATE TONIGHT INTO SUNDAY MORNING.
WHATEVER EVENTUALLY PANS OUT...WILL DEFINITELY BUMP UP POPS
TONIGHT AND SUNDAY. HAVE INCLUDED A MENTION OF SEVERE ACROSS THE
SOUTHWEST THIS EVENING. AFTER MIDNIGHT...ALTHOUGH A SEVERE STORM
CANNOT BE RULED OUT...THINK WE WILL BE ON THE DOWNWARD TREND.
HIGH TEMPERATURES ON SUNDAY WILL DEPEND GREATLY ON THE ONGOING
CONVECTION THAT TRACKS ACROSS CENTRAL INTO EASTERN NORTH DAKOTA
DURING THE DAY. UTILIZED A BLEND WITH MORE WEIGHT TOWARD RAW MODEL
GUIDANCE WHICH USUALLY WORKS WELL IN A CHANGEABLE WEATHER PATTERN.
THIS RESULTS IN A NICE GRADIENT FROM UPPER 60S ACROSS THE NORTH
CENTRAL WHERE SHOWERS HANG ON INTO THE AFTERNOON...TO AROUND 80
OVER THE SOUTHWEST WHERE WE CLEAR OUT EARLY AND TEMPERATURES
REBOUND NICELY. THE WEST WILL ALSO BEGIN TO DESTABILIZE ONCE
AGAIN SUNDAY AFTERNOON...WITH A FAVORABLE SHEAR ENVIRONMENT
REMAINING OVER THE AREA. WILL NOT MENTION SEVERE WORDING AT THIS
TIME BUT WILL KEEP A CHANCE OF THUNDERSTORMS REMAINING ACROSS ALL
OF WESTERN NORTH DAKOTA SUNDAY AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 321 PM CDT SAT AUG 3 2013
CHANCES FOR PRECIPITATION WILL DECREASE WEST TO EAST SUNDAY
EVENING INTO EARLY MONDAY MORNING AS A MID LEVEL SHORTWAVE TROUGH
AND AREA OF SURFACE LOW PRESSURE MOVE EAST INTO THE GREAT LAKES
REGION AND SURFACE HIGH PRESSURE BUILDS ACROSS WESTERN NORTH
DAKOTA.
WE REMAIN IN NORTHWEST FLOW ALOFT MONDAY WITH UPPER LEVEL RIDGING
ACROSS THE SOUTHERN PLAINS AND DEEP LOW PRESSURE OVER THE WESTERN
HUDSON BAY. WILL SEE INCREASING CHANCES OF SHOWERS/THUNDERSTORMS
LATER MONDAY WEST AND NORTH AND MONDAY NIGHT AREA WIDE AS THE
UPPER LOW DRIFTS SOUTHWARD ALLOWING FOR INCREASING CYCLONIC FLOW
ALOFT INTO THE NORTHERN PLAINS. MODELS ARE KEYING IN ON TWO
DISTINCT MID LEVEL IMPULSES ROTATING THROUGH THE FLOW ACROSS NORTH
DAKOTA...IN ADDITION TO A SFC TROUGH/COLD FRONTAL BOUNDARY PUSHING
SOUTH ACROSS THE STATE INTO TUESDAY MORNING. BEST CHANCES FOR
PRECIPITATION WILL BE ACROSS MY NORTH AND EAST WHERE BEST LOW
LEVEL FORCING IS CURRENTLY FORECAST.
BY TUESDAY AFTERNOON...THE UPPER LEVEL LOW IS FORECAST TO BE ABOUT
250-400 MILES NORTHEAST OF LAKE WINNIPEG MAINTAINING STRONG
CYCLONIC FLOW ALOFT...WHICH PERSISTS THROUGH WEDNESDAY. LINGERING
LOW LEVEL MOISTURE COUPLED WITH EMBEDDED ENERGY IN THE FLOW ALOFT
WILL MAINTAIN SOME CHANCE FOR DIURNALLY DRIVEN SHOWERS/ISOLATED
THUNDERSTORMS BOTH TUESDAY AND WEDNESDAY. HOWEVER...LOW LEVEL
FORCING IS PROGGED WEAK SO WIDESPREAD PRECIPITATION IS NOT
EXPECTED. IN ADDITION...MUCH COOLER CANADIAN AIR WILL FILTER INTO
THE REGION TUESDAY/TUESDAY NIGHT AND WEDNESDAY (HIGHS IN THE
LOW/MID 70S AND LOWS TUESDAY NIGHT LOW 50S/UPPER 40S).
UPPER LOW PROPAGATES SLOWLY EAST TO OVER ONTARIO THURSDAY...THEN
INTO EASTERN CANADA BY SATURDAY. HIGH PRESSURE IS FORECAST TO
BUILD ACROSS THE DAKOTAS THURSDAY AND THURSDAY NIGHT...REMAINING
IN PLACE WELL INTO SATURDAY. THIS WILL LEAD TO MAINLY DRY
CONDITIONS AND CONTINUED BELOW NORMAL TEMPERATURES OVER MOST OF
THE CWA THROUGH THE REMAINDER OF THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1157 PM CDT SAT AUG 3 2013
THUNDERSTORMS EXPECTED TO SPREAD EAST...IMPACTING KBIS AND KMOT
OVERNIGHT INTO SUNDAY MORNING...AND PERHAPS KJMS BY MIDDAY. BRIEF
MVFR VSBYS WILL BE POSSIBLE IN THE STRONGER STORMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TM
SHORT TERM...TWH
LONG TERM...NH
AVIATION...RK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1205 AM CDT SUN AUG 4 2013
.UPDATE...
ISSUED AT 1157 PM CDT SAT AUG 3 2013
UPDATE TO CLEAR GOLDEN VALLEY/BILLINGS FROM SEVERE THUNDERSTORM
WATCH. PER LATEST SWOMCD...MARGINAL SEVERE WEATHER THREAT MAY
PERSIST INTO THE EARLY MORNING AND WILL KEEP REMAINDER OF WATCH
GOING. MADE SOME ADDITIONAL CHANGES TO POPS PER LATEST RADAR TRENDS.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 321 PM CDT SAT AUG 3 2013
MAIN FORECAST PROBLEM IN THE SHORT TERM PERIOD WILL BE
THUNDERSTORM CHANCES.
CURRENTLY...ALTHOUGH NOT REAL WARM...A MOIST UNSTABLE ATMOSPHERE
IS DEVELOPING ACROSS EASTERN MONTANA AND FAR WESTERN NORTH DAKOTA.
A SHORTWAVE INDICATED OVER NORTH CENTRAL MONTANA IN A PROGRESSIVE
BAND OF WESTERLIES HAS INITIATED CONVECTION WEST OF GLASGOW.
EXPECT CONVECTION TO CONTINUE TO INCREASE IN AN AREA OF STEEPENING
LAPSE RATES AND STRONG DEEP LAYER SHEAR. THE 18 UTC HRRR INDICATES
DISCRETE SUPERCELLS TRACKING ACROSS EASTERN MONTANA THIS AFTERNOON
AND EVENING...CLIPPING THE FAR SOUTHWEST LATE THIS EVENING. THE
12 UTC WRF AND HIRES-NMM/ARW ARE SIMILAR BUT MAYBE A BIT LATER AND
TRANSITION FROM DISCRETE CELLS INTO AN MCS THAT TRACKS ACROSS THE
SOUTHWEST AND FAR SOUTH CENTRAL LATE TONIGHT INTO SUNDAY MORNING.
WHATEVER EVENTUALLY PANS OUT...WILL DEFINITELY BUMP UP POPS
TONIGHT AND SUNDAY. HAVE INCLUDED A MENTION OF SEVERE ACROSS THE
SOUTHWEST THIS EVENING. AFTER MIDNIGHT...ALTHOUGH A SEVERE STORM
CANNOT BE RULED OUT...THINK WE WILL BE ON THE DOWNWARD TREND.
HIGH TEMPERATURES ON SUNDAY WILL DEPEND GREATLY ON THE ONGOING
CONVECTION THAT TRACKS ACROSS CENTRAL INTO EASTERN NORTH DAKOTA
DURING THE DAY. UTILIZED A BLEND WITH MORE WEIGHT TOWARD RAW MODEL
GUIDANCE WHICH USUALLY WORKS WELL IN A CHANGEABLE WEATHER PATTERN.
THIS RESULTS IN A NICE GRADIENT FROM UPPER 60S ACROSS THE NORTH
CENTRAL WHERE SHOWERS HANG ON INTO THE AFTERNOON...TO AROUND 80
OVER THE SOUTHWEST WHERE WE CLEAR OUT EARLY AND TEMPERATURES
REBOUND NICELY. THE WEST WILL ALSO BEGIN TO DESTABILIZE ONCE
AGAIN SUNDAY AFTERNOON...WITH A FAVORABLE SHEAR ENVIRONMENT
REMAINING OVER THE AREA. WILL NOT MENTION SEVERE WORDING AT THIS
TIME BUT WILL KEEP A CHANCE OF THUNDERSTORMS REMAINING ACROSS ALL
OF WESTERN NORTH DAKOTA SUNDAY AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 321 PM CDT SAT AUG 3 2013
CHANCES FOR PRECIPITATION WILL DECREASE WEST TO EAST SUNDAY
EVENING INTO EARLY MONDAY MORNING AS A MID LEVEL SHORTWAVE TROUGH
AND AREA OF SURFACE LOW PRESSURE MOVE EAST INTO THE GREAT LAKES
REGION AND SURFACE HIGH PRESSURE BUILDS ACROSS WESTERN NORTH
DAKOTA.
WE REMAIN IN NORTHWEST FLOW ALOFT MONDAY WITH UPPER LEVEL RIDGING
ACROSS THE SOUTHERN PLAINS AND DEEP LOW PRESSURE OVER THE WESTERN
HUDSON BAY. WILL SEE INCREASING CHANCES OF SHOWERS/THUNDERSTORMS
LATER MONDAY WEST AND NORTH AND MONDAY NIGHT AREA WIDE AS THE
UPPER LOW DRIFTS SOUTHWARD ALLOWING FOR INCREASING CYCLONIC FLOW
ALOFT INTO THE NORTHERN PLAINS. MODELS ARE KEYING IN ON TWO
DISTINCT MID LEVEL IMPULSES ROTATING THROUGH THE FLOW ACROSS NORTH
DAKOTA...IN ADDITION TO A SFC TROUGH/COLD FRONTAL BOUNDARY PUSHING
SOUTH ACROSS THE STATE INTO TUESDAY MORNING. BEST CHANCES FOR
PRECIPITATION WILL BE ACROSS MY NORTH AND EAST WHERE BEST LOW
LEVEL FORCING IS CURRENTLY FORECAST.
BY TUESDAY AFTERNOON...THE UPPER LEVEL LOW IS FORECAST TO BE ABOUT
250-400 MILES NORTHEAST OF LAKE WINNIPEG MAINTAINING STRONG
CYCLONIC FLOW ALOFT...WHICH PERSISTS THROUGH WEDNESDAY. LINGERING
LOW LEVEL MOISTURE COUPLED WITH EMBEDDED ENERGY IN THE FLOW ALOFT
WILL MAINTAIN SOME CHANCE FOR DIURNALLY DRIVEN SHOWERS/ISOLATED
THUNDERSTORMS BOTH TUESDAY AND WEDNESDAY. HOWEVER...LOW LEVEL
FORCING IS PROGGED WEAK SO WIDESPREAD PRECIPITATION IS NOT
EXPECTED. IN ADDITION...MUCH COOLER CANADIAN AIR WILL FILTER INTO
THE REGION TUESDAY/TUESDAY NIGHT AND WEDNESDAY (HIGHS IN THE
LOW/MID 70S AND LOWS TUESDAY NIGHT LOW 50S/UPPER 40S).
UPPER LOW PROPAGATES SLOWLY EAST TO OVER ONTARIO THURSDAY...THEN
INTO EASTERN CANADA BY SATURDAY. HIGH PRESSURE IS FORECAST TO
BUILD ACROSS THE DAKOTAS THURSDAY AND THURSDAY NIGHT...REMAINING
IN PLACE WELL INTO SATURDAY. THIS WILL LEAD TO MAINLY DRY
CONDITIONS AND CONTINUED BELOW NORMAL TEMPERATURES OVER MOST OF
THE CWA THROUGH THE REMAINDER OF THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1157 PM CDT SAT AUG 3 2013
THUNDERSTORMS EXPECTED TO SPREAD EAST...IMPACTING KBIS AND KMOT
OVERNIGHT INTO SUNDAY MORNING...AND PERHAPS KJMS BY MIDDAY. BRIEF
MVFR VSBYS WILL BE POSSIBLE IN THE STRONGER STORMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RK
SHORT TERM...TWH
LONG TERM...NH
AVIATION...RK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
928 PM EDT MON AUG 5 2013
.SYNOPSIS...
WEAK DISTURBANCES WILL MOVE ACROSS THE AREA TONIGHT AND TUESDAY. A
MORE PRONOUNCED SYSTEM WILL MOVE ACROSS THE AREA LATE TUESDAY
NIGHT INTO WEDNESDAY. A COLD FRONT WILL MOVE THROUGH THE REGION
WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
ABUNDANT MOISTURE ALOFT IN NORTHWESTERLY FLOW IS HELPING TO BRING
PATCHES OF SPRINKLES AND LIGHT RAIN ACROSS CENTRAL INDIANA AND
CENTRAL OHIO THIS EVENING. THE TREND OVER THE PAST FEW HOURS HAS
BEEN TO WEAKEN THE AREAS OF PRECIPITATION. HAVE FORECAST THESE
SHOWERS TO GRADUALLY DISSIPATE AS THEY SHIFT EAST TO SOUTHEAST
THROUGH THE LATE EVENING. OF NOTEWORTHINESS...LATEST RUC IS TRYING
TO REDEVELOP SHOWERS ACROSS NORTHERN INDIANA EARLY IN THE MORNING
AND THESE SHOWERS COULD MAKE IT TO OUR NORTHWESTERN ZONES AROUND
SUNRISE. THIS MORNING ACTIVITY IS ALSO COARSELY DEPICTED IN THE
12Z ECMWF AND THEREFORE MAY NEED TO INTRODUCE POPS ACROSS THOSE
ZONES AFTER 11Z IF THESE ADDITIONAL SHOWERS BEGIN TO FILL IN
UPSTREAM OVER THE NEXT FEW HOURS. OTHERWISE...EXPECT MOSTLY CLOUDY
SKIES WITH TEMPERATURES FALLING INTO THE UPPER 60S ACROSS THE
WEST...TO THE UPPER 50S ACROSS OUR EASTERN ZONES.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
A WEAK DISTURBANCE WILL BRING A CHANCE FOR SOME SHOWERS AND
THUNDERSTORMS ACROSS THE FA ON TUESDAY. A MORE WELL DEFINED SHORT
WAVE WILL APPROACH THE AREA TUESDAY NIGHT INTO WEDNESDAY. THIS
FEATURE WILL BRING WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY TO
THE AREA. MODELS HAVE BEEN INCONSISTENT WITH WHERE THE HEAVIEST
RAIN WILL BE WITH THIS FEATURE. THE BEST CHANCE FOR HEAVIER
RAINFALL WILL BE ACROSS SOUTHERN PORTIONS OF THE FA AND THEREFORE
ADDED FLOODING POTENTIAL IN TO THE HWO ACROSS THIS AREA. DECIDED
AGAINST A FLASH FLOOD WATCH DUE TO RELATIVELY HIGH FFG VALUES AND
MODEL INCONSISTENCIES WITH WHERE THE HEAVIEST RAINFALL WILL OCCUR.
ADDITIONAL PRECIPITATION WILL BE POSSIBLE ACROSS THE FA WEDNESDAY
NIGHT AS A COLD FRONT MOVES THROUGH.
SOUTHERLY FLOW ACROSS THE FA ON TUESDAY WILL ALLOW FOR
TEMPERATURES TO RISE INTO THE 80S. TEMPERATURES ON WEDNESDAY WILL
BE COOLER WITH HIGHS IN THE UPPER 70S TO LOWER 80S DUE TO MORE
WIDESPREAD PRECIPITATION AND CLOUD COVER ACROSS THE FA.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
MOST GUIDANCE HAS TRENDED TOWARDS A DRIER SOLUTION FOR THURSDAY. A
WEAK FRONTAL BOUNDARY WILL REMAIN ACROSS THE SOUTH BUT FORCING DOES
NOT LOOK PARTICULARLY STRONG AT THIS TIME. SO HAVE ONLY KEPT LOW
CHANCE POPS IN FOR THAT PERIOD.
CHANCE OF RAIN WILL INCREASE AGAIN LATE THURSDAY NIGHT AND
PARTICULARLY INTO FRIDAY AS A WAVE MOVES ALONG THE STALLED FRONT.
HAVE INCREASED POPS TO LIKELY ACROSS THE SOUTHERN COUNTIES. THIS
WILL PUSH OFF TO THE EAST DURING FRIDAY NIGHT. HIGH PRESSURE WILL
BUILD IN FOR THE WEEKEND. THERE IS THE POTENTIAL FOR A WEAK SYSTEM
TO SWING INTO THE REGION BY MONDAY. BUT SIGNAL IS NOT VERY STRONG
AND AT DAY 7 HAVE KEPT ANY CHANCE OF RAIN RATHER LOW.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
LARGE AREA OF MID TO HIGH LEVEL CLOUDS WILL MOVE ACROSS THE AREA
THROUGHOUT THE LATE EVENING AND INTO EARLY TUESDAY MORNING.
UPSTREAM OF THIS DECK...A LARGE AREA OF VFR LOW CLOUDS APPEARS
POISED TO SPREAD ACROSS OUR AREA. LIGHT RAIN ACROSS CENTRAL
INDIANA MOVING INTO CENTRAL OHIO THIS EVENING MAY AFFECT KDAY
THROUGH MIDNIGHT. OTHERWISE...THE REMAINDER OF THE TERMINALS
SHOULD STAY DRY TONIGHT. THE VFR LOW CLOUD DECK WILL LIKELY
REMAIN ACROSS THE TERMINALS THROUGHOUT THE DAY...BECOMING
SCATTERED AT TIMES. SHOWERS WILL BECOME POSSIBLE LATE IN THE
AFTERNOON WEST OF INTERSTATE 75...WITH THE BEST CHANCE FOR A
SHOWER BEING AT KDAY.
OUTLOOK...THUNDERSTORMS POSSIBLE WEDNESDAY INTO THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...NOVAK
NEAR TERM...LATTO
SHORT TERM...NOVAK
LONG TERM...
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
940 AM EDT SUN AUG 4 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE AREA TODAY FROM THE NORTHWEST.
THE HIGH WILL MOVE TO THE EAST COAST ON TUESDAY. THIS WILL ALLOW
LOW PRESSURE TO MOVE INTO THE GREAT LAKES AND OHIO VALLEY REGION
WEDNESDAY AND WEDNESDAY NIGHT WITH A COLD FRONT EXPECTED ACROSS
THE AREA ON THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED TO ADD ISOLATED SHOWERS TO EXTREME NORTHEAST OHIO AND
NORTHWEST PA THROUGH EARLY AFTERNOON. NOTHING ON THE RADAR BUT
BASED ON THE SATELLITE AND ENOUGH MOISTURE AND A LAKE AND 850 MB
TEMPERATURE DIFFERENCE OF OVER 13C THE THREAT IS REAL. ELSEWHERE
SOME CUMULUS WILL DEVELOP BY EARLY AFTERNOON. NO SIGNIFICANT
ADJUSTMENTS TO THE HIGHS.
ORIGINAL...WEAK TROUGH AND WIND SHIFT...FORECAST ON THE HRRR AND
VISIBLE ON RADAR MANAGED TO EXPLOIT THE INSTABILITY OVER THE WARM
LAKE TO PRODUCE A FEW SHOWERS AND THUNDERSTORMS SHORTLY AFTER
MIDNIGHT. EXPECT THE SHOWERS TO DISSIPATE AS THEY DROP SOUTH
ACROSS THE AREA THROUGH THE NIGHT. WILL HAVE A SLIGHT CHANCE POP
FOR THE NORTHEAST FOR THE FIRST HALF OF THE DAY HOWEVER WITH SO
MUCH DRY AIR IN THE MID LEVELS MOVING IN NOT EXPECTING MUCH. LOW
LEVEL MOISTURE STILL IN PLACE HOWEVER SO AM THINKING WE WILL HAVE
A GOOD CU FIELD TO DEVELOP...POSSIBLY GOING BROKEN FOR A FEW HOURS
BEFORE MIXING OUT BACK TO SCATTERED. OUTSIDE CHANCE POPS WILL NEED
TO BE RAISED AS 850MB TEMPS DROP TO +7C AND WITH THE LAKE AT +20C
IT COULD BE PROBLEMATIC IF AIRMASS HAS A BIT MORE MID LEVEL
MOISTURE THAN ANTICIPATED. AFTERNOON TEMPS INDICATIVE OF MID TO
LATE SEPTEMBER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
HIGH PRESSURE WILL BE ACROSS THE AREA TONIGHT AND EARLY MONDAY.
EXPECTING MOSTLY CLEAR SKIES WITH WELL BELOW NORMAL TEMPS. MONDAY
AFTERNOON THE HIGH MOVES EAST AND THE NAM AND GFS SHOW SUFFICIENT
MOISTURE FOR AT LEAST THE THREAT OF A SHOWER IN THE WEST DURING
THE AFTERNOON. WILL HAVE LOW CHANCE POPS FOR THE WESTERN TIER OF
COUNTIES WITH A SLIGHT CHANCE EAST TO ROUGHLY A CLEVELAND TO
MANSFIELD LINE. MONDAY NIGHT WENT A BIT ABOVE POP GUIDANCE AND
BROUGHT CHANCE POPS EAST ACROSS THE REMAINDER OF THE AREA GIVEN
DEEP MOISTURE...OVERRUNNING FLOW AND JET ENERGY MOVING THROUGH THE
AREA. TUESDAY THROUGH WEDNESDAY LOW PRESSURE TO THE WEST WILL
SLOWLY MOVE EAST INCREASING MOISTURE AND INSTABILITY ACROSS THE
REGION. WILL BRING IN INCREASING CHANCE POPS FOR SCATTERED
SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. TEMPS APPROACHING
NORMAL.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
STILL UNCLEAR AT THIS POINT WHERE EXACTLY THE FRONT WILL STALL OUT
ON THURSDAY. A WEDGE OF DRY AIR ALOFT IS PULLED OVER THE AREA BUT
ENOUGH LOW LEVEL MOISTURE MAY REMAIN FOR SCATTERED
SHOWERS/THUNDERSTORMS TO DEVELOP FROM CENTRAL TO NORTHEAST OHIO IN
THE VICINITY OF THE BOUNDARY. CHANCES WILL BE LOWER BY FRIDAY
ALTHOUGH CAN NOT ENTIRELY RULE OUT SOMETHING POPPING UP AS MODELS
CONTINUE TO STRUGGLE WITH RESOLVING SHORTWAVE ENERGY MOVING AROUND
THE SOUTHERN PERIPHERY OF THE TROUGH. THE UPPER LOW WILL TRAVERSE
THE UPPER GREAT LAKES FRIDAY NIGHT INTO SATURDAY AND FINALLY PUSH A
STRONGER COLD FRONT SOUTH ACROSS THE AREA. TEMPERATURES WILL DROP
FROM NEAR 80 ON THURSDAY TO THE LOWER 70S ON SUNDAY.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE OVER THE UPPER MIDWEST WILL EXPAND EAST ACROSS THE
CENTRAL GREAT LAKES INTO MONDAY. SATELLITE IMAGERY SHOWS LAKE EFFECT
CLOUDS OFF OF EASTERN LAKE ERIE WITH BKN VFR STRATOCU TO START THE
PERIOD AT CLE/ERI/YNG. THESE CLOUDS WILL SCATTER OUT THROUGH EARLY
AFTERNOON AS WE MIX INTO DRIER AIR ALOFT. WINDS WILL REMAIN OUT OF
THE NORTH THROUGH THE AFTERNOON BEFORE BECOMING LIGHT AND VARIABLE
AFTER 00Z.
.OUTLOOK...NON-VFR POSSIBLE IN SHOWERS/STORMS MONDAY NIGHT AND
AGAIN WEDNESDAY INTO THURSDAY.
&&
.MARINE...
WAVES WILL BUILD THIS MORNING AS NORTHERLY WINDS OF 10 TO 20 KNOTS
CONTINUE ON THE LAKE BEHIND A COLD FRONT. WAVES WILL REACH 2 TO 4
FEET EAST OF AVON AND WILL HAVE TO MONITOR CONDITIONS FOR THE NEED
FOR A SMALL CRAFT ADVISORY. THIS WILL ALSO PRESENT A MODERATE RISK
FOR RIP CURRENTS FOR AREAS EAST OF THE ISLANDS. HIGH PRESSURE OVER
THE UPPER MIDWEST WILL BUILD EAST ACROSS THE LAKE OVERNIGHT THROUGH
MONDAY BRINGING LIGHT WIND AND GOOD MARINE CONDITIONS. SOUTHERLY
WIND WILL INCREASE FROM TUESDAY INTO WEDNESDAY AHEAD OF THE
NEXT LOW PRESSURE SYSTEM.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...KIELTYKA/TK
SHORT TERM...TK
LONG TERM...KEC
AVIATION...KEC
MARINE...KEC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
744 AM EDT SUN AUG 4 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE AREA TODAY FROM THE NORTHWEST.
THE HIGH WILL MOVE TO THE EAST COAST ON TUESDAY. THIS WILL ALLOW
LOW PRESSURE TO MOVE INTO THE GREAT LAKES AND OHIO VALLEY REGION
WEDNESDAY AND WEDNESDAY NIGHT WITH A COLD FRONT EXPECTED ACROSS
THE AREA ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...WILL ADD MENTION OF CLOUDS EARLY NORTHEAST. OTHERWISE NO
CHANGES.
ORIGINAL...WEAK TROUGH AND WIND SHIFT...FORECAST ON THE HRRR AND
VISIBLE ON RADAR MANAGED TO EXPLOIT THE INSTABILITY OVER THE WARM
LAKE TO PRODUCE A FEW SHOWERS AND THUNDERSTORMS SHORTLY AFTER
MIDNIGHT. EXPECT THE SHOWERS TO DISSIPATE AS THEY DROP SOUTH
ACROSS THE AREA THROUGH THE NIGHT. WILL HAVE A SLIGHT CHANCE POP
FOR THE NORTHEAST FOR THE FIRST HALF OF THE DAY HOWEVER WITH SO
MUCH DRY AIR IN THE MID LEVELS MOVING IN NOT EXPECTING MUCH. LOW
LEVEL MOISTURE STILL IN PLACE HOWEVER SO AM THINKING WE WILL HAVE
A GOOD CU FIELD TO DEVELOP...POSSIBLY GOING BROKEN FOR A FEW HOURS
BEFORE MIXING OUT BACK TO SCATTERED. OUTSIDE CHANCE POPS WILL NEED
TO BE RAISED AS 850MB TEMPS DROP TO +7C AND WITH THE LAKE AT +20C
IT COULD BE PROBLEMATIC IF AIRMASS HAS A BIT MORE MID LEVEL
MOISTURE THAN ANTICIPATED. AFTERNOON TEMPS INDICATIVE OF MID TO
LATE SEPTEMBER.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
HIGH PRESSURE WILL BE ACROSS THE AREA TONIGHT AND EARLY MONDAY.
EXPECTING MOSTLY CLEAR SKIES WITH WELL BELOW NORMAL TEMPS. MONDAY
AFTERNOON THE HIGH MOVES EAST AND THE NAM AND GFS SHOW SUFFICIENT
MOISTURE FOR AT LEAST THE THREAT OF A SHOWER IN THE WEST DURING
THE AFTERNOON. WILL HAVE LOW CHANCE POPS FOR THE WESTERN TIER OF
COUNTIES WITH A SLIGHT CHANCE EAST TO ROUGHLY A CLEVELAND TO
MANSFIELD LINE. MONDAY NIGHT WENT A BIT ABOVE POP GUIDANCE AND
BROUGHT CHANCE POPS EAST ACROSS THE REMAINDER OF THE AREA GIVEN
DEEP MOISTURE...OVERRUNNING FLOW AND JET ENERGY MOVING THROUGH THE
AREA. TUESDAY THROUGH WEDNESDAY LOW PRESSURE TO THE WEST WILL
SLOWLY MOVE EAST INCREASING MOISTURE AND INSTABILITY ACROSS THE
REGION. WILL BRING IN INCREASING CHANCE POPS FOR SCATTERED
SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. TEMPS APPROACHING
NORMAL.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
STILL UNCLEAR AT THIS POINT WHERE EXACTLY THE FRONT WILL STALL OUT
ON THURSDAY. A WEDGE OF DRY AIR ALOFT IS PULLED OVER THE AREA BUT
ENOUGH LOW LEVEL MOISTURE MAY REMAIN FOR SCATTERED
SHOWERS/THUNDERSTORMS TO DEVELOP FROM CENTRAL TO NORTHEAST OHIO IN
THE VICINITY OF THE BOUNDARY. CHANCES WILL BE LOWER BY FRIDAY
ALTHOUGH CAN NOT ENTIRELY RULE OUT SOMETHING POPPING UP AS MODELS
CONTINUE TO STRUGGLE WITH RESOLVING SHORTWAVE ENERGY MOVING AROUND
THE SOUTHERN PERIPHERY OF THE TROUGH. THE UPPER LOW WILL TRAVERSE
THE UPPER GREAT LAKES FRIDAY NIGHT INTO SATURDAY AND FINALLY PUSH A
STRONGER COLD FRONT SOUTH ACROSS THE AREA. TEMPERATURES WILL DROP
FROM NEAR 80 ON THURSDAY TO THE LOWER 70S ON SUNDAY.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE OVER THE UPPER MIDWEST WILL EXPAND EAST ACROSS THE
CENTRAL GREAT LAKES INTO MONDAY. SATELLITE IMAGERY SHOWS LAKE EFFECT
CLOUDS OFF OF EASTERN LAKE ERIE WITH BKN VFR STRATOCU TO START THE
PERIOD AT CLE/ERI/YNG. THESE CLOUDS WILL SCATTER OUT THROUGH EARLY
AFTERNOON AS WE MIX INTO DRIER AIR ALOFT. WINDS WILL REMAIN OUT OF
THE NORTH THROUGH THE AFTERNOON BEFORE BECOMING LIGHT AND VARIABLE
AFTER 00Z.
.OUTLOOK...NON-VFR POSSIBLE IN SHOWERS/STORMS MONDAY NIGHT AND
AGAIN WEDNESDAY INTO THURSDAY.
&&
.MARINE...
WAVES WILL BUILD THIS MORNING AS NORTHERLY WINDS OF 10 TO 20 KNOTS
CONTINUE ON THE LAKE BEHIND A COLD FRONT. WAVES WILL REACH 2 TO 4
FEET EAST OF AVON AND WILL HAVE TO MONITOR CONDITIONS FOR THE NEED
FOR A SMALL CRAFT ADVISORY. THIS WILL ALSO PRESENT A MODERATE RISK
FOR RIP CURRENTS FOR AREAS EAST OF THE ISLANDS. HIGH PRESSURE OVER
THE UPPER MIDWEST WILL BUILD EAST ACROSS THE LAKE OVERNIGHT THROUGH
MONDAY BRINGING LIGHT WIND AND GOOD MARINE CONDITIONS. SOUTHERLY
WIND WILL INCREASE FROM TUESDAY INTO WEDNESDAY AHEAD OF THE
NEXT LOW PRESSURE SYSTEM.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...KEC
AVIATION...KEC
MARINE...KEC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
619 AM EDT SUN AUG 4 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE AREA TODAY FROM THE NORTHWEST.
THE HIGH WILL MOVE TO THE EAST COAST ON TUESDAY. THIS WILL ALLOW
LOW PRESSURE TO MOVE INTO THE GREAT LAKES AND OHIO VALLEY REGION
WEDNESDAY AND WEDNESDAY NIGHT WITH A COLD FRONT EXPECTED ACROSS
THE AREA ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...WILL ADD MENTION OF CLOUDS EARLY NORTHEAST. OTHERWISE NO
CHANGES.
ORIGINAL...WEAK TROUGH AND WIND SHIFT...FORECAST ON THE HRRR AND
VISIBLE ON RADAR MANAGED TO EXPLOIT THE INSTABILITY OVER THE WARM
LAKE TO PRODUCE A FEW SHOWERS AND THUNDERSTORMS SHORTLY AFTER
MIDNIGHT. EXPECT THE SHOWERS TO DISSIPATE AS THEY DROP SOUTH
ACROSS THE AREA THROUGH THE NIGHT. WILL HAVE A SLIGHT CHANCE POP
FOR THE NORTHEAST FOR THE FIRST HALF OF THE DAY HOWEVER WITH SO
MUCH DRY AIR IN THE MID LEVELS MOVING IN NOT EXPECTING MUCH. LOW
LEVEL MOISTURE STILL IN PLACE HOWEVER SO AM THINKING WE WILL HAVE
A GOOD CU FIELD TO DEVELOP...POSSIBLY GOING BROKEN FOR A FEW HOURS
BEFORE MIXING OUT BACK TO SCATTERED. OUTSIDE CHANCE POPS WILL NEED
TO BE RAISED AS 850MB TEMPS DROP TO +7C AND WITH THE LAKE AT +20C
IT COULD BE PROBLEMATIC IF AIRMASS HAS A BIT MORE MID LEVEL
MOISTURE THAN ANTICIPATED. AFTERNOON TEMPS INDICATIVE OF MID TO
LATE SEPTEMBER.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
HIGH PRESSURE WILL BE ACROSS THE AREA TONIGHT AND EARLY MONDAY.
EXPECTING MOSTLY CLEAR SKIES WITH WELL BELOW NORMAL TEMPS. MONDAY
AFTERNOON THE HIGH MOVES EAST AND THE NAM AND GFS SHOW SUFFICIENT
MOISTURE FOR AT LEAST THE THREAT OF A SHOWER IN THE WEST DURING
THE AFTERNOON. WILL HAVE LOW CHANCE POPS FOR THE WESTERN TIER OF
COUNTIES WITH A SLIGHT CHANCE EAST TO ROUGHLY A CLEVELAND TO
MANSFIELD LINE. MONDAY NIGHT WENT A BIT ABOVE POP GUIDANCE AND
BROUGHT CHANCE POPS EAST ACROSS THE REMAINDER OF THE AREA GIVEN
DEEP MOISTURE...OVERRUNNING FLOW AND JET ENERGY MOVING THROUGH THE
AREA. TUESDAY THROUGH WEDNESDAY LOW PRESSURE TO THE WEST WILL
SLOWLY MOVE EAST INCREASING MOISTURE AND INSTABILITY ACROSS THE
REGION. WILL BRING IN INCREASING CHANCE POPS FOR SCATTERED
SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. TEMPS APPROACHING
NORMAL.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
STILL UNCLEAR AT THIS POINT WHERE EXACTLY THE FRONT WILL STALL OUT
ON THURSDAY. A WEDGE OF DRY AIR ALOFT IS PULLED OVER THE AREA BUT
ENOUGH LOW LEVEL MOISTURE MAY REMAIN FOR SCATTERED
SHOWERS/THUNDERSTORMS TO DEVELOP FROM CENTRAL TO NORTHEAST OHIO IN
THE VICINITY OF THE BOUNDARY. CHANCES WILL BE LOWER BY FRIDAY
ALTHOUGH CAN NOT ENTIRELY RULE OUT SOMETHING POPPING UP AS MODELS
CONTINUE TO STRUGGLE WITH RESOLVING SHORTWAVE ENERGY MOVING AROUND
THE SOUTHERN PERIPHERY OF THE TROUGH. THE UPPER LOW WILL TRAVERSE
THE UPPER GREAT LAKES FRIDAY NIGHT INTO SATURDAY AND FINALLY PUSH A
STRONGER COLD FRONT SOUTH ACROSS THE AREA. TEMPERATURES WILL DROP
FROM NEAR 80 ON THURSDAY TO THE LOWER 70S ON SUNDAY.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
A BAND OF SHOWERS AND ISOLATED THUNDERSTORMS DEVELOPED OVER LAKE
ERIE AND WILL MOVE THROUGH CLE BY 07Z. CONDITIONS WILL BRIEFLY DROP
TO MVFR AND POSSIBLY IFR FOR A FEW MINUTES IN MODERATE TO HEAVY
RAIN. ELSEWHERE CONDITIONS ARE EXPECTED TO REMAIN VFR BUT SCT-BKN
CLOUDS ARE EXPECTED AS COLD ADVECTION INCREASES BEHIND THE FRONT.
SATELLITE IMAGERY SHOWS ONE BAND OF CLOUDS OVER LAKE ERIE WITH
ANOTHER BAND OF CLOUDS ACROSS CENTRAL MICHIGAN PUSHING SOUTHEAST.
WINDS WILL REMAIN OUT OF THE NORTH THROUGH THE AFTERNOON BEFORE
BECOMING LIGHT AND VARIABLE AFTER 00Z.
.OUTLOOK...NON-VFR POSSIBLE IN SHOWERS/STORMS MONDAY NIGHT AND
AGAIN WEDNESDAY INTO THURSDAY.
&&
.MARINE...
WAVES WILL BUILD THIS MORNING AS NORTHERLY WINDS OF 10 TO 20 KNOTS
CONTINUE ON THE LAKE BEHIND A COLD FRONT. WAVES WILL REACH 2 TO 4
FEET EAST OF AVON AND WILL HAVE TO MONITOR CONDITIONS FOR THE NEED
FOR A SMALL CRAFT ADVISORY. THIS WILL ALSO PRESENT A MODERATE RISK
FOR RIP CURRENTS FOR AREAS EAST OF THE ISLANDS. HIGH PRESSURE OVER
THE UPPER MIDWEST WILL BUILD EAST ACROSS THE LAKE OVERNIGHT THROUGH
MONDAY BRINGING LIGHT WIND AND GOOD MARINE CONDITIONS. SOUTHERLY
WIND WILL INCREASE FROM TUESDAY INTO WEDNESDAY AHEAD OF THE
NEXT LOW PRESSURE SYSTEM.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...KEC
AVIATION...KEC
MARINE...KEC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
356 AM EDT SUN AUG 4 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE AREA TODAY FROM THE NORTHWEST.
THE HIGH WILL MOVE TO THE EAST COAST ON TUESDAY. THIS WILL ALLOW
LOW PRESSURE TO MOVE INTO THE GREAT LAKES AND OHIO VALLEY REGION
WEDNESDAY AND WEDNESDAY NIGHT WITH A COLD FRONT EXPECTED ACROSS
THE AREA ON THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
WEAK TROUGH AND WIND SHIFT...FORECAST ON THE HRRR AND VISIBLE ON
RADAR MANAGED TO EXPLOIT THE INSTABILITY OVER THE WARM LAKE TO
PRODUCE A FEW SHOWERS AND THUNDERSTORMS SHORTLY AFTER MIDNIGHT.
EXPECT THE SHOWERS TO DISSIPATE AS THEY DROP SOUTH ACROSS THE AREA
THROUGH THE NIGHT. WILL HAVE A SLIGHT CHANCE POP FOR THE NORTHEAST
FOR THE FIRST HALF OF THE DAY HOWEVER WITH SO MUCH DRY AIR IN THE
MID LEVELS MOVING IN NOT EXPECTING MUCH. LOW LEVEL MOISTURE STILL
IN PLACE HOWEVER SO AM THINKING WE WILL HAVE A GOOD CU FIELD TO
DEVELOP...POSSIBLY GOING BROKEN FOR A FEW HOURS BEFORE MIXING OUT
BACK TO SCATTERED. OUTSIDE CHANCE POPS WILL NEED TO BE RAISED AS
850MB TEMPS DROP TO +7C AND WITH THE LAKE AT +20C IT COULD BE
PROBLEMATIC IF AIRMASS HAS A BIT MORE MID LEVEL MOISTURE THAN
ANTICIPATED. AFTERNOON TEMPS INDICATIVE OF MID TO LATE SEPTEMBER.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
HIGH PRESSURE WILL BE ACROSS THE AREA TONIGHT AND EARLY MONDAY.
EXPECTING MOSTLY CLEAR SKIES WITH WELL BELOW NORMAL TEMPS. MONDAY
AFTERNOON THE HIGH MOVES EAST AND THE NAM AND GFS SHOW SUFFICIENT
MOISTURE FOR AT LEAST THE THREAT OF A SHOWER IN THE WEST DURING
THE AFTERNOON. WILL HAVE LOW CHANCE POPS FOR THE WESTERN TIER OF
COUNTIES WITH A SLIGHT CHANCE EAST TO ROUGHLY A CLEVELAND TO
MANSFIELD LINE. MONDAY NIGHT WENT A BIT ABOVE POP GUIDANCE AND
BROUGHT CHANCE POPS EAST ACROSS THE REMAINDER OF THE AREA GIVEN
DEEP MOISTURE...OVERRUNNING FLOW AND JET ENERGY MOVING THROUGH THE
AREA. TUESDAY THROUGH WEDNESDAY LOW PRESSURE TO THE WEST WILL
SLOWLY MOVE EAST INCREASING MOISTURE AND INSTABILITY ACROSS THE
REGION. WILL BRING IN INCREASING CHANCE POPS FOR SCATTERED
SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. TEMPS APPROACHING
NORMAL.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
STILL UNCLEAR AT THIS POINT WHERE EXACTLY THE FRONT WILL STALL OUT
ON THURSDAY. A WEDGE OF DRY AIR ALOFT IS PULLED OVER THE AREA BUT
ENOUGH LOW LEVEL MOISTURE MAY REMAIN FOR SCATTERED
SHOWERS/THUNDERSTORMS TO DEVELOP FROM CENTRAL TO NORTHEAST OHIO IN
THE VICINITY OF THE BOUNDARY. CHANCES WILL BE LOWER BY FRIDAY
ALTHOUGH CAN NOT ENTIRELY RULE OUT SOMETHING POPPING UP AS MODELS
CONTINUE TO STRUGGLE WITH RESOLVING SHORTWAVE ENERGY MOVING AROUND
THE SOUTHERN PERIPHERY OF THE TROUGH. THE UPPER LOW WILL TRAVERSE
THE UPPER GREAT LAKES FRIDAY NIGHT INTO SATURDAY AND FINALLY PUSH A
STRONGER COLD FRONT SOUTH ACROSS THE AREA. TEMPERATURES WILL DROP
FROM NEAR 80 ON THURSDAY TO THE LOWER 70S ON SUNDAY.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
A BAND OF SHOWERS AND ISOLATED THUNDERSTORMS DEVELOPED OVER LAKE
ERIE AND WILL MOVE THROUGH CLE BY 07Z. CONDITIONS WILL BRIEFLY DROP
TO MVFR AND POSSIBLY IFR FOR A FEW MINUTES IN MODERATE TO HEAVY
RAIN. ELSEWHERE CONDITIONS ARE EXPECTED TO REMAIN VFR BUT SCT-BKN
CLOUDS ARE EXPECTED AS COLD ADVECTION INCREASES BEHIND THE FRONT.
SATELLITE IMAGERY SHOWS ONE BAND OF CLOUDS OVER LAKE ERIE WITH
ANOTHER BAND OF CLOUDS ACROSS CENTRAL MICHIGAN PUSHING SOUTHEAST.
WINDS WILL REMAIN OUT OF THE NORTH THROUGH THE AFTERNOON BEFORE
BECOMING LIGHT AND VARIABLE AFTER 00Z.
.OUTLOOK...NON-VFR POSSIBLE IN SHOWERS/STORMS MONDAY NIGHT AND
AGAIN WEDNESDAY INTO THURSDAY.
&&
.MARINE...
WAVES WILL BUILD THIS MORNING AS NORTHERLY WINDS OF 10 TO 20 KNOTS
CONTINUE ON THE LAKE BEHIND A COLD FRONT. WAVES WILL REACH 2 TO 4
FEET EAST OF AVON AND WILL HAVE TO MONITOR CONDITIONS FOR THE NEED
FOR A SMALL CRAFT ADVISORY. THIS WILL ALSO PRESENT A MODERATE RISK
FOR RIP CURRENTS FOR AREAS EAST OF THE ISLANDS. HIGH PRESSURE OVER
THE UPPER MIDWEST WILL BUILD EAST ACROSS THE LAKE OVERNIGHT THROUGH
MONDAY BRINGING LIGHT WIND AND GOOD MARINE CONDITIONS. SOUTHERLY
WIND WILL INCREASE FROM TUESDAY INTO WEDNESDAY AHEAD OF THE
NEXT LOW PRESSURE SYSTEM.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...KEC
AVIATION...KEC
MARINE...KEC
AREA FORECAST DISCUSSION
NWS TULSA OK
1132 PM CDT SAT AUG 3 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
CONVECTION CONTINUES TO GRADUALLY EXPAND INTO NE OK...AND THIS
TREND IS EXPECTED TO CONTINUE THROUGH THE OVERNIGHT HOURS.
EVENTUALLY WIDESPREAD CONVECTION IS EXPECTED ACROSS NE OK / FAR NW
AR WITH ASSOCIATED AVIATION IMPACTS. FLIGHT CONDITION ARE LIKELY
TO IMPROVE AREA WIDE BY MID AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 848 PM CDT SAT AUG 3 2013/
..UPDATE...
DISCUSSION...
FORECAST IS LARGELY ON TRACK...WITH THE MAIN CHANGES BEING TO
SPEED UP THE INCREASE IN POPS TONIGHT AND EARLY TOMORROW BY ABOUT
3 HOURS IN ACCORDANCE WITH THE LATEST OBSERVATIONAL AND MESOSCALE
MODEL DATA. THE LATEST HRRR HAS A FAIRLY GOOD HANDLE ON THE
ONGOING STORMS ACROSS THE OKLAHOMA AND TEXAS PANHANDLES...AND INTO
NORTHWEST OKLAHOMA. THIS ACTIVITY SHOULD CONTINUE TO INCREASE
OVERNIGHT AND TRACK TO THE EAST AND SOUTHEAST ALONG THE
INSTABILITY AXIS NEAR AND JUST SOUTH OF THE OKLAHOMA/KANSAS
BORDER. ALTHOUGH SOME OF THE FLASH FLOOD WATCH AREA /NAMELY THE
ARKANSAS COUNTIES/ MAY NOT SEE HEAVY RAIN UNTIL AFTER 12Z...IT
APPEARS INCREASINGLY LIKELY THAT PARTS OF THE NORTHEAST OKLAHOMA
WATCH AREA WILL SEE RAINS BEFORE THEN. DUE TO THIS...THE WATCH
WILL NOW BEGIN AT 09Z. RAINFALL AMOUNTS STILL LOOK TO BE IN THE 1
TO 2 INCH RANGE ACROSS THE WATCH AREA...WITH LOCALLY HIGHER
AMOUNTS. RELATIVELY MINOR TWEAKS WERE MADE TO OTHER FORECAST
ELEMENTS.
PREV DISCUSSION... /ISSUED 625 PM CDT SAT AUG 3 2013/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
ONGOING LIGHT CONVECTION ACROSS NE OK WILL LIKELY CONTINUE THROUGH
THE EVENING WITH LITTLE TO NO FLIGHT IMPACTS. A LARGE THUNDERSTORM
COMPLEX IS EXPECTED TO MOVE INTO NE OK LATE TONIGHT...AND CONTINUE
INTO NW AR AROUND SUNRISE WITH CORRESPONDING AVIATION IMPACTS
PERSISTING INTO THE AFTERNOON.
PREV DISCUSSION... /ISSUED 326 PM CDT SAT AUG 3 2013/
DISCUSSION...
OVERNIGHT/EARLY MORNING MCS PROVED TO BE AN EFFICIENT
RAINMAKER...WITH 3+ INCH RAINFALL AMOUNTS AND LOCALIZED FLOODING
REPORTED ACROSS NW AR. ONLY A FEW LINGERING SHOWERS NOTED ACROSS THE
FORECAST AREA AT THIS TIME...BUT EXPECT YET ANOTHER BOUT OF
SHOWERS/THUNDERSTORMS LATE TONIGHT AND INTO TOMORROW.
SHORT-RANGE GUIDANCE IS SIMILAR KEYING ON A SUBTLE MID-LEVEL
SHORTWAVE ACROSS THE CNTRL ROCKIES ROUNDING THE TOP OF THE RIDGE AND
MOVING INTO KS LATE TONIGHT. EXPECT DEVELOPMENT TO OCCUR IN
ASSOCIATION WITH THIS FEATURE LATER THIS AFTERNOON/EVENING ACROSS
PARTS OF WRN KS...WITH VEERING LOW-LEVEL JET AIDING AN EWD/SEWD
MOVEMENT INTO FAR NE OK/NW AR BY SUNDAY MORNING. WITH PRECIP WATER
VALUES REMAINING AT OR ABOVE 2 INCHES...EXPECT LOCALLY HEAVY RAINFALL
ACROSS SOME AREAS THAT HAVE ALREADY RECEIVED SEVERAL INCHES OF RAIN
OVER THE PAST 5-10 DAYS. WILL GO WITH A FLASH FLOOD WATCH FOR SUNDAY
FOR FAR NERN OK AND NW AR. WATCH MAY NEED TO BE EXTENDED INTO SUNDAY
NIGHT WITH FORECAST AREA REMAINING UNDER NWLY UPPER FLOW.
UPPER RIDGE EXPANDS SOME BY EARLY NEXT WEEK...WITH LOW-LEVEL FLOW
BECOMING MORE SWLY. THIS WILL BRING IN WARMER AIR AND SHOULD
SHUNT MOST OF THE CONVECTION TO OUR N...ALTHOUGH WILL KEEP SOME LOW
POPS GOING ALONG THE NRN FRINGES OF THE FORECAST AREA. WILL LIKELY
NEED HEAT HEADLINES FOR MONDAY AND TUESDAY...WITH AFTERNOON HEAT
INDICES LIKELY BREACHING 105F ACROSS A LARGE PART OF THE AREA.
A WEAK FRONTAL BOUNDARY IS EXPECTED TO DROP INTO THE REGION
WEDNESDAY NIGHT AND LIKELY STALL NEAR THE RED RIVER FOR THE END OF
THE WEEK. ECMWF RATHER BULLISH WITH POST-FRONTAL PRECIP AND COOLER
TEMPS THURSDAY/FRIDAY...AND HAVE GONE WITH A GENERAL GFS/ECWMF BLEND
FOR NOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 74 92 76 98 / 60 80 30 10
FSM 76 92 73 97 / 20 50 40 30
MLC 75 97 76 99 / 20 20 20 10
BVO 74 87 74 97 / 80 80 40 10
FYV 71 87 73 92 / 40 70 50 40
BYV 69 85 71 91 / 40 80 50 40
MKO 74 91 74 98 / 30 50 30 20
MIO 72 85 73 94 / 70 80 50 30
F10 75 94 75 98 / 30 40 20 10
HHW 75 98 75 99 / 10 20 10 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH FROM 4 AM SUNDAY TO 7 PM SUNDAY FOR OKZ056-
OKZ057-OKZ058-OKZ063.
AR...FLASH FLOOD WATCH FROM 4 AM SUNDAY TO 7 PM SUNDAY FOR ARZ001-
ARZ002-ARZ010-ARZ011.
&&
$$
AVIATION...07
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1259 PM CDT SUN AUG 4 2013
.UPDATE...
ISSUED AT 1044 AM CDT SUN AUG 4 2013
FIRST WEAK WAVE NOW PULLING AWAY ACROSS SOUTHERN MINNESOTA...WITH
CONVECTIVE CLUSTER IN NORTHEAST NEBRASKA AND EXTREME SOUTHEAST
SOUTH DAKOTA. ANOTHER WEAK IMPULSE MOVING ACROSS SOUTH CENTRAL NORTH
DAKOTA AND FAR NORTHERN SOUTH DAKOTA INITIATING NEW CONVECTION
ALONG MID LEVEL BOUNDARY BACK TOWARD NORTH OF KPIR TO KD07. NORTHERN
AREA DEFINITELY LOOKS TO BE THE ONLY LARGER SCALE SUPPORT FOR LIFT
GOING INTO THE AFTERNOON...AND EXPECT SOUTHERN AREA TO START A
MORE NOTABLE WEAKENING TREND IN COVERAGE IN NEXT COUPLE OF HOURS
AS IT PROGRESSES TOWARD SIOUX CITY AND POINT SOUTH/EAST...AS
THERMODYNAMIC SUPPORT FOR DEVELOPMENT CERTAINLY DIMINISHES
EASTWARD...AND DEGREE OF ANY INSTABILITY REALLY ONLY SUPPORTS A
THUNDER THREAT THROUGH MIDDAY IN THE FAR WEST/SOUTH. LIKEWISE...
SHOULD SEE GRADUAL DEMISE OF CLUSTER OF SHOWERS THAT PASSED NEAR
KHON AS IT APPROACHES KFSD TOWARD NOON.
DESPITE CERTAINTY IN THE SHORT TERM BEING FAIRLY LOW...AND MODEL
PERFORMANCE IN WEAKLY FORCED PATTERN DISMAL...HAVE SOME CONFIDENCE
THAT MUCH OF THE AREA THIS AFTERNOON INTO EARLY EVENING SHOULD BE
FREE OF CONVECTION. WILL MAINTAIN AN ISOLATED TO SCATTERED MENTION
IN THE FAR NORTHERN TIER ALONG GLANCING INFLUENCE OF NORTHERN WAVE...
CARRYING WITH IT A GRADUAL SPREAD OF THUNDER MENTION EASTWARD.
TEMPERATURES LOOKED GENERALLY OK FOR THE DAYTIME MAX...BUT MADE AN
ATTEMPT TO ACCOUNT FOR EXPECTED PRECIP AREAS AND COOLER OUTFLOW
FOR THE SHORTER TERM TO DIURNAL TRENDS...AND DID TRIM A FEW AREAS
DOWN A COUPLE DEGREES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT SUN AUG 4 2013
MODELS STRUGGLING WITH ONGOING ACTIVITY ACROSS CENTRAL SOUTH DAKOTA
WHICH HAS DEVELOPED WITH AN INCREASING LOW LEVEL JET AND MID LEVEL
WAVE. DRY AIR TO THE EAST AND MINIMAL INSTABILITY IS EXPECTED TO
CAUSE A DOWNWARD TREND IN THIS CONVECTION AS IT ENTERS OUR CWA. OF
ALL THE GUIDANCE...SEEMS LIKE HRRR IS CLOSEST TO REALITY...WITH THE
0Z ECMWF ALSO NOT TOO BAD. BOTH OF THESE MODELS SUGGEST ACTIVITY
DOES INDEED WEAKEN AND DISSIPATE AS IT PUSHES EAST. HAVE HIGH CHANCE
TO LIKELY POPS THIS MORNING WEST OF THE JAMES RIVER...FROM ABOUT 10Z
TO 15Z. NOTHING SEVERE BUT WOULD EXPECT AT LEAST SOME LIGHTNING
ACTIVITY WITH THE STORMS. SHOWERS COULD MAKE IT AS FAR EAST AS
INTERSTATE 29 BY 13Z...BUT NOT REAL CONFIDENT IT WILL HOLD TOGETHER
EVEN THAT FAR...SO WILL ONLY GO SLIGHT CHANCE POPS. PLUS GIVEN THE
EXPECTED WEAKENING STATE...AND LACK OF INSTABILITY...PROBABLY WILL
NOT BE ANY LIGHTNING WITH ANYTHING THAT DOES MANAGE TO GET EAST OF
THE JAMES RIVER. TEND TO THINK WE SEE A LULL IN THE ACTIVITY DURING
THE AFTERNOON HOURS. BUT GIVEN WEAK FORCING...MID LEVEL MOISTURE
PRESENT...ONGOING ACTIVITY CONTINUING TO DEVELOP OVER NORTHWEST
SOUTH DAKOTA...AND THE GENERALLY LOW PREDICTABILITY OF THE
PATTERN...WILL KEEP A LOW CHANCE POPS IN THE WEST THROUGH THE
DAY...WITH SLIGHT CHANCES TO INTERSTATE 29. DAY SHIFT MAY END UP
BEING ABLE TO REMOVE THESE IF IT BECOMES MORE APPARENT DURING THE
MORNING THAT WE SEE A LULL IN THE ACTION. HIGHS TODAY ARE TRICKY AND
DEPENDENT ON REMNANT CLOUD COVER. THINK IT PROBABLY STAYS MOSTLY
CLOUDY FOR MUCH OF THE DAY. DID BUMP HIGHS UP SOME WITH SOME OF THE
NEWER GUIDANCE COMING IN A BIT WARMER...BUT GIVEN CLOUD COVER
CONCERNS DID NOT WANT TO GO TOO WARM...AND WENT WITH MAINLY MID AND
UPPER 70S. IF WE SOMEHOW ARE ABLE TO GET MORE SUN TODAY...HIGHS
WOULD END UP SEVERAL DEGREES WARMER. SO ANOTHER THING THE DAY SHIFT
WILL HAVE TO MONITOR.
UNFORTUNATELY...FORECAST CONFIDENCE DOES NOT INCREASE TONIGHT. THE
CORE OF THE UPPER LEVEL SUPPORT WILL DIVE SOUTHEAST ACROSS
MINNESOTA. SEEMS LIKE A GOOD BET THAT WE SEE ANOTHER ROUND OF
NOCTURNAL CONVECTION ACROSS THE NORTHERN PLAINS. BEST FORCING IS TO
THE NORTHEAST...WITH BEST INSTABILITY AS YOU GO SOUTHWEST. THINK
THE BEST THREAT WILL BE ACROSS SOUTHWEST MINNESOTA CLOSEST TO THE
BEST FORCING...BUT GIVEN INSTABILITY TO THE SOUTHWEST...AND SOME OF
THE HI RES MODELS SHOWING CONVECTION FIRING IN OUR WEST...WILL KEEP
CHANCE POPS ACROSS THE WHOLE CWA. CONFIDENCE IS TOO LOW IN PLACEMENT
AND TIMING TO WARRANT ANY LIKELY POPS AT THIS TIME. ELEVATED
INSTABILITY AROUND 1000 J/KG TONIGHT WOULD SUGGEST A PRETTY GOOD
LIGHTNING THREAT WITH ANYTHING THAT DOES FORM TONIGHT...HOWEVER
SEVERE THREAT SHOULD REMAIN PRETTY LOW...WITH THE ELEVATED NATURE
LIMITING WIND THREAT...AND CAPE PROBABLY TOO LOW FOR MUCH OF A HAIL
THREAT. LOWS WILL BE MILDER TONIGHT...GENERALLY LOW AND MID 60S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 415 AM CDT SUN AUG 4 2013
FOR MONDAY...A COLD FRONT DROPS ACROSS THE REGION EARLY IN THE
DAY...AND OTHER THAN A SLIGHT CHANCE OF POPS IN THE SOUTH AND EAST
EARLY THINK THAT THE REMAINDER OF THE DAY WILL BE DRY IN
SUBSIDENCE/DRYING BEHIND AN EXITING SHORTWAVE. ONLY WEAK COLD AIR
ADVECTION BEHIND THE FRONT...AND WITH MORE SUN THAN TODAY
TEMPERATURES WILL WARM INTO THE UPPER 70S TO MID 80S ACROSS THE AREA
BY AFTERNOON. MOSTLY CLEAR SKIES WILL RULE FOR THE FIRST HALF OF
MONDAY NIGHT...BEFORE CLOUDS BEGIN TO INCREASE IN THE WEST THE
LATTER HALF OF THE NIGHT WITH MID LEVEL WARM AIR ADVECTION. CANNOT
RULE OUT THAT ISOLATED THUNDERSTORMS COULD MAKE IT INTO OUR FAR WEST
BY EARLY TUESDAY MORNING WITH THETA E ADVECTION ON A DEVELOPING LOW
LEVEL JET THROUGH WESTERN SOUTH DAKOTA. LOWS ON MONDAY NIGHT LOOKING
TO BE IN THE UPPER 50S TO LOWER 60S.
ANOTHER COLD FRONT ENCROACHES ON OUR AREA BY TUESDAY AFTERNOON...AND
MAY HAVE BETTER CHANCE OF THUNDERSTORMS ACROSS THE AREA WITH
INCREASING 850 MB THETA E ADVECTION AND INCREASING INSTABILITY OUT
AHEAD OF THE SYSTEM...WITH UPPER LEVEL SUPPORT AS A SHORTWAVE TRACKS
OVER THE AREA. THEIR DOES APPEAR TO BE ENOUGH CAPE AND SHEAR IN OUR
SOUTH AND WEST IN THE AFTERNOON THAT SEVERE STORMS WOULD BE
POSSIBLE. THERMAL PROFILES WARM JUST A BIT OUT AHEAD OF THE
FRONT...THOUGH HIGHS WILL BE DEPENDENT ON TIMING AND EVOLUTION OF
CONVECTION...BUT POTENTIALLY WILL REACH THE UPPER 70S TO MID 80S.
THE FRONTAL BOUNDARY WILL FINALLY PULL ACROSS THE AREA ON TUESDAY
EVENING WITH ANY CONVECTION ENDING FROM WEST TO EAST.
IN THE EXTENDED...WEDNESDAY THROUGH SATURDAY...MODELS IN DECENT
AGREEMENT ON THE DEVELOPMENT OF A CLOSED UPPER LEVEL LOW OVER
CENTRAL CANADA FOR MIDWEEK. THIS FEATURE WILL THEN SLOWLY MIGRATE TO
THE NORTHERN GREAT LAKES REGION BY THE END OF THE WEEK. THIS WILL
KEEP OUR AREA IN A NORTHWESTERLY UPPER LEVEL FLOW WITH BELOW NORMAL
TEMPERATURES THROUGH THE PERIOD. DOES NOT APPEAR TO BE ANY
OUTSTANDING CHANCES OF PRECIPITATION THROUGH THE EXTENDED...THOUGH
THE BEST CHANCE WOULD LOOK TO BE IN THE THURSDAY TO THURSDAY NIGHT
TIME FRAME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1259 PM CDT SUN AUG 4 2013
FAR FROM A CLEAR PICTURE ON THE EVOLUTION OVER THE NEXT 12 TO 24
HOURS. WILL SEE AREA OF CONVECTION AROUND KSUX MOVE THROUGH WITH
ANY REDUCED VISIBILITY IN RAIN LIKELY REMAINING OUT OF MVFR BY
1830Z. IN ITS WAKE...MAY SEE SOME SOME SCATTERED TO BROKEN LOWER
BASED CUMULUS IN THE LOWER MISSOURI VALLEY THROUGH THE AFTERNOON.
ONLY SHOWERS/THUNDER AROUND THE AREA UNTIL AT LEAST THE EVENING
EXPECTED TO BE NEAR MID LEVEL BOUNDARY AROUND KHON...BUT JUST TOO
UNCERTAIN AND LOW OF COVERAGE TO MENTION IN THE KHON TAF AT THIS
POINT. STRONGER FORCING FOR CONVECTION LOOKS TO DEVELOP DURING THE
EVENING HOURS AND INTRODUCED A FEW HOURS AROUND THE MOST CERTAIN
TIMING FOR KFSD AND KHON...AND ANY STORMS WILL THIS TIME LIKELY
HAVE MVFR CONDITIONS. KEPT THE LATTER ACTIVITY CLEAR OF KSUX. WAKE
OF ANY OVERNIGHT CONVECTION IS LIKELY TO RESULT IN MVFR TO IFR
CEILINGS INTO THE MORNING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHAPMAN
SHORT TERM...CHENARD
LONG TERM...JM
AVIATION...CHAPMAN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1044 AM CDT SUN AUG 4 2013
.UPDATE...
ISSUED AT 1044 AM CDT SUN AUG 4 2013
FIRST WEAK WAVE NOW PULLING AWAY ACROSS SOUTHERN MINNESOTA...WITH
CONVECTIVE CLUSTER IN NORTHEAST NEBRASKA AND EXTREME SOUTHEAST
SOUTH DAKOTA. ANOTHER WEAK IMPULSE MOVING ACROSS SOUTH CENTRAL NORTH
DAKOTA AND FAR NORTHERN SOUTH DAKOTA INITIATING NEW CONVECTION
ALONG MID LEVEL BOUNDARY BACK TOWARD NORTH OF KPIR TO KD07. NORTHERN
AREA DEFINITELY LOOKS TO BE THE ONLY LARGER SCALE SUPPORT FOR LIFT
GOING INTO THE AFTERNOON...AND EXPECT SOUTHERN AREA TO START A
MORE NOTABLE WEAKENING TREND IN COVERAGE IN NEXT COUPLE OF HOURS
AS IT PROGRESSES TOWARD SIOUX CITY AND POINT SOUTH/EAST...AS
THERMODYNAMIC SUPPORT FOR DEVELOPMENT CERTAINLY DIMINISHES
EASTWARD...AND DEGREE OF ANY INSTABILITY REALLY ONLY SUPPORTS A
THUNDER THREAT THROUGH MIDDAY IN THE FAR WEST/SOUTH. LIKEWISE...
SHOULD SEE GRADUAL DEMISE OF CLUSTER OF SHOWERS THAT PASSED NEAR
KHON AS IT APPROACHES KFSD TOWARD NOON.
DESPITE CERTAINTY IN THE SHORT TERM BEING FAIRLY LOW...AND MODEL
PERFORMANCE IN WEAKLY FORCED PATTERN DISMAL...HAVE SOME CONFIDENCE
THAT MUCH OF THE AREA THIS AFTERNOON INTO EARLY EVENING SHOULD BE
FREE OF CONVECTION. WILL MAINTAIN AN ISOLATED TO SCATTERED MENTION
IN THE FAR NORTHERN TIER ALONG GLANCING INFLUENCE OF NORTHERN WAVE...
CARRYING WITH IT A GRADUAL SPREAD OF THUNDER MENTION EASTWARD.
TEMPERATURES LOOKED GENERALLY OK FOR THE DAYTIME MAX...BUT MADE AN
ATTEMPT TO ACCOUNT FOR EXPECTED PRECIP AREAS AND COOLER OUTFLOW
FOR THE SHORTER TERM TO DIURNAL TRENDS...AND DID TRIM A FEW AREAS
DOWN A COUPLE DEGREES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT SUN AUG 4 2013
MODELS STRUGGLING WITH ONGOING ACTIVITY ACROSS CENTRAL SOUTH DAKOTA
WHICH HAS DEVELOPED WITH AN INCREASING LOW LEVEL JET AND MID LEVEL
WAVE. DRY AIR TO THE EAST AND MINIMAL INSTABILITY IS EXPECTED TO
CAUSE A DOWNWARD TREND IN THIS CONVECTION AS IT ENTERS OUR CWA. OF
ALL THE GUIDANCE...SEEMS LIKE HRRR IS CLOSEST TO REALITY...WITH THE
0Z ECMWF ALSO NOT TOO BAD. BOTH OF THESE MODELS SUGGEST ACTIVITY
DOES INDEED WEAKEN AND DISSIPATE AS IT PUSHES EAST. HAVE HIGH CHANCE
TO LIKELY POPS THIS MORNING WEST OF THE JAMES RIVER...FROM ABOUT 10Z
TO 15Z. NOTHING SEVERE BUT WOULD EXPECT AT LEAST SOME LIGHTNING
ACTIVITY WITH THE STORMS. SHOWERS COULD MAKE IT AS FAR EAST AS
INTERSTATE 29 BY 13Z...BUT NOT REAL CONFIDENT IT WILL HOLD TOGETHER
EVEN THAT FAR...SO WILL ONLY GO SLIGHT CHANCE POPS. PLUS GIVEN THE
EXPECTED WEAKENING STATE...AND LACK OF INSTABILITY...PROBABLY WILL
NOT BE ANY LIGHTNING WITH ANYTHING THAT DOES MANAGE TO GET EAST OF
THE JAMES RIVER. TEND TO THINK WE SEE A LULL IN THE ACTIVITY DURING
THE AFTERNOON HOURS. BUT GIVEN WEAK FORCING...MID LEVEL MOISTURE
PRESENT...ONGOING ACTIVITY CONTINUING TO DEVELOP OVER NORTHWEST
SOUTH DAKOTA...AND THE GENERALLY LOW PREDICTABILITY OF THE
PATTERN...WILL KEEP A LOW CHANCE POPS IN THE WEST THROUGH THE
DAY...WITH SLIGHT CHANCES TO INTERSTATE 29. DAY SHIFT MAY END UP
BEING ABLE TO REMOVE THESE IF IT BECOMES MORE APPARENT DURING THE
MORNING THAT WE SEE A LULL IN THE ACTION. HIGHS TODAY ARE TRICKY AND
DEPENDENT ON REMNANT CLOUD COVER. THINK IT PROBABLY STAYS MOSTLY
CLOUDY FOR MUCH OF THE DAY. DID BUMP HIGHS UP SOME WITH SOME OF THE
NEWER GUIDANCE COMING IN A BIT WARMER...BUT GIVEN CLOUD COVER
CONCERNS DID NOT WANT TO GO TOO WARM...AND WENT WITH MAINLY MID AND
UPPER 70S. IF WE SOMEHOW ARE ABLE TO GET MORE SUN TODAY...HIGHS
WOULD END UP SEVERAL DEGREES WARMER. SO ANOTHER THING THE DAY SHIFT
WILL HAVE TO MONITOR.
UNFORTUNATELY...FORECAST CONFIDENCE DOES NOT INCREASE TONIGHT. THE
CORE OF THE UPPER LEVEL SUPPORT WILL DIVE SOUTHEAST ACROSS
MINNESOTA. SEEMS LIKE A GOOD BET THAT WE SEE ANOTHER ROUND OF
NOCTURNAL CONVECTION ACROSS THE NORTHERN PLAINS. BEST FORCING IS TO
THE NORTHEAST...WITH BEST INSTABILITY AS YOU GO SOUTHWEST. THINK
THE BEST THREAT WILL BE ACROSS SOUTHWEST MINNESOTA CLOSEST TO THE
BEST FORCING...BUT GIVEN INSTABILITY TO THE SOUTHWEST...AND SOME OF
THE HI RES MODELS SHOWING CONVECTION FIRING IN OUR WEST...WILL KEEP
CHANCE POPS ACROSS THE WHOLE CWA. CONFIDENCE IS TOO LOW IN PLACEMENT
AND TIMING TO WARRANT ANY LIKELY POPS AT THIS TIME. ELEVATED
INSTABILITY AROUND 1000 J/KG TONIGHT WOULD SUGGEST A PRETTY GOOD
LIGHTNING THREAT WITH ANYTHING THAT DOES FORM TONIGHT...HOWEVER
SEVERE THREAT SHOULD REMAIN PRETTY LOW...WITH THE ELEVATED NATURE
LIMITING WIND THREAT...AND CAPE PROBABLY TOO LOW FOR MUCH OF A HAIL
THREAT. LOWS WILL BE MILDER TONIGHT...GENERALLY LOW AND MID 60S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 415 AM CDT SUN AUG 4 2013
FOR MONDAY...A COLD FRONT DROPS ACROSS THE REGION EARLY IN THE
DAY...AND OTHER THAN A SLIGHT CHANCE OF POPS IN THE SOUTH AND EAST
EARLY THINK THAT THE REMAINDER OF THE DAY WILL BE DRY IN
SUBSIDENCE/DRYING BEHIND AN EXITING SHORTWAVE. ONLY WEAK COLD AIR
ADVECTION BEHIND THE FRONT...AND WITH MORE SUN THAN TODAY
TEMPERATURES WILL WARM INTO THE UPPER 70S TO MID 80S ACROSS THE AREA
BY AFTERNOON. MOSTLY CLEAR SKIES WILL RULE FOR THE FIRST HALF OF
MONDAY NIGHT...BEFORE CLOUDS BEGIN TO INCREASE IN THE WEST THE
LATTER HALF OF THE NIGHT WITH MID LEVEL WARM AIR ADVECTION. CANNOT
RULE OUT THAT ISOLATED THUNDERSTORMS COULD MAKE IT INTO OUR FAR WEST
BY EARLY TUESDAY MORNING WITH THETA E ADVECTION ON A DEVELOPING LOW
LEVEL JET THROUGH WESTERN SOUTH DAKOTA. LOWS ON MONDAY NIGHT LOOKING
TO BE IN THE UPPER 50S TO LOWER 60S.
ANOTHER COLD FRONT ENCROACHES ON OUR AREA BY TUESDAY AFTERNOON...AND
MAY HAVE BETTER CHANCE OF THUNDERSTORMS ACROSS THE AREA WITH
INCREASING 850 MB THETA E ADVECTION AND INCREASING INSTABILITY OUT
AHEAD OF THE SYSTEM...WITH UPPER LEVEL SUPPORT AS A SHORTWAVE TRACKS
OVER THE AREA. THEIR DOES APPEAR TO BE ENOUGH CAPE AND SHEAR IN OUR
SOUTH AND WEST IN THE AFTERNOON THAT SEVERE STORMS WOULD BE
POSSIBLE. THERMAL PROFILES WARM JUST A BIT OUT AHEAD OF THE
FRONT...THOUGH HIGHS WILL BE DEPENDENT ON TIMING AND EVOLUTION OF
CONVECTION...BUT POTENTIALLY WILL REACH THE UPPER 70S TO MID 80S.
THE FRONTAL BOUNDARY WILL FINALLY PULL ACROSS THE AREA ON TUESDAY
EVENING WITH ANY CONVECTION ENDING FROM WEST TO EAST.
IN THE EXTENDED...WEDNESDAY THROUGH SATURDAY...MODELS IN DECENT
AGREEMENT ON THE DEVELOPMENT OF A CLOSED UPPER LEVEL LOW OVER
CENTRAL CANADA FOR MIDWEEK. THIS FEATURE WILL THEN SLOWLY MIGRATE TO
THE NORTHERN GREAT LAKES REGION BY THE END OF THE WEEK. THIS WILL
KEEP OUR AREA IN A NORTHWESTERLY UPPER LEVEL FLOW WITH BELOW NORMAL
TEMPERATURES THROUGH THE PERIOD. DOES NOT APPEAR TO BE ANY
OUTSTANDING CHANCES OF PRECIPITATION THROUGH THE EXTENDED...THOUGH
THE BEST CHANCE WOULD LOOK TO BE IN THE THURSDAY TO THURSDAY NIGHT
TIME FRAME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 644 AM CDT SUN AUG 4 2013
AREA OF SHOWERS AND EMBEDDED THUNDER MOVING EAST ACROSS THE CWA THIS
MORNING. THINK IT WILL CONTINUE TO WEAKEN AND DISSIPATE AS IT MOVES
INTO THE DRYER AND MORE STABLE AIR IN THE EAST. A FEW SHOWERS MAY
MAKE IT TO INTERSTATE 29 BETWEEN 8 AM AND 11 AM...BUT SHOULD
DISSIPATE AFTER THEN. NOT EXPECTING ANY LIGHTNING TO IMPACT THE TAF
SITES WITH THIS ACTIVITY. TONIGHT...WE MAY SEE ANOTHER ROUND OF
STORMS MOVE THROUGH FROM NORTHWEST TO SOUTHEAST. CONFIDENCE IN
COVERAGE AND TIMING IS CURRENTLY TOO LOW TO PUT A MENTION IN THE
TAFS. GUIDANCE IS SUGGESTING WE COULD SEE SOME MVFR STRATUS MOVE IN
AHEAD OF THE COLD FRONT TONIGHT. HOWEVER NOT COMPLETELY SOLD ON THAT
HAPPENING...SO WILL KEEP THE TAF VFR FOR THE TIME BEING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHAPMAN
SHORT TERM...CHENARD
LONG TERM...JM
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
649 AM CDT SUN AUG 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT SUN AUG 4 2013
MODELS STRUGGLING WITH ONGOING ACTIVITY ACROSS CENTRAL SOUTH DAKOTA
WHICH HAS DEVELOPED WITH AN INCREASING LOW LEVEL JET AND MID LEVEL
WAVE. DRY AIR TO THE EAST AND MINIMAL INSTABILITY IS EXPECTED TO
CAUSE A DOWNWARD TREND IN THIS CONVECTION AS IT ENTERS OUR CWA. OF
ALL THE GUIDANCE...SEEMS LIKE HRRR IS CLOSEST TO REALITY...WITH THE
0Z ECMWF ALSO NOT TOO BAD. BOTH OF THESE MODELS SUGGEST ACTIVITY
DOES INDEED WEAKEN AND DISSIPATE AS IT PUSHES EAST. HAVE HIGH CHANCE
TO LIKELY POPS THIS MORNING WEST OF THE JAMES RIVER...FROM ABOUT 10Z
TO 15Z. NOTHING SEVERE BUT WOULD EXPECT AT LEAST SOME LIGHTNING
ACTIVITY WITH THE STORMS. SHOWERS COULD MAKE IT AS FAR EAST AS
INTERSTATE 29 BY 13Z...BUT NOT REAL CONFIDENT IT WILL HOLD TOGETHER
EVEN THAT FAR...SO WILL ONLY GO SLIGHT CHANCE POPS. PLUS GIVEN THE
EXPECTED WEAKENING STATE...AND LACK OF INSTABILITY...PROBABLY WILL
NOT BE ANY LIGHTNING WITH ANYTHING THAT DOES MANAGE TO GET EAST OF
THE JAMES RIVER. TEND TO THINK WE SEE A LULL IN THE ACTIVITY DURING
THE AFTERNOON HOURS. BUT GIVEN WEAK FORCING...MID LEVEL MOISTURE
PRESENT...ONGOING ACTIVITY CONTINUING TO DEVELOP OVER NORTHWEST
SOUTH DAKOTA...AND THE GENERALLY LOW PREDICTABILITY OF THE
PATTERN...WILL KEEP A LOW CHANCE POPS IN THE WEST THROUGH THE
DAY...WITH SLIGHT CHANCES TO INTERSTATE 29. DAY SHIFT MAY END UP
BEING ABLE TO REMOVE THESE IF IT BECOMES MORE APPARENT DURING THE
MORNING THAT WE SEE A LULL IN THE ACTION. HIGHS TODAY ARE TRICKY AND
DEPENDENT ON REMNANT CLOUD COVER. THINK IT PROBABLY STAYS MOSTLY
CLOUDY FOR MUCH OF THE DAY. DID BUMP HIGHS UP SOME WITH SOME OF THE
NEWER GUIDANCE COMING IN A BIT WARMER...BUT GIVEN CLOUD COVER
CONCERNS DID NOT WANT TO GO TOO WARM...AND WENT WITH MAINLY MID AND
UPPER 70S. IF WE SOMEHOW ARE ABLE TO GET MORE SUN TODAY...HIGHS
WOULD END UP SEVERAL DEGREES WARMER. SO ANOTHER THING THE DAY SHIFT
WILL HAVE TO MONITOR.
UNFORTUNATELY...FORECAST CONFIDENCE DOES NOT INCREASE TONIGHT. THE
CORE OF THE UPPER LEVEL SUPPORT WILL DIVE SOUTHEAST ACROSS
MINNESOTA. SEEMS LIKE A GOOD BET THAT WE SEE ANOTHER ROUND OF
NOCTURNAL CONVECTION ACROSS THE NORTHERN PLAINS. BEST FORCING IS TO
THE NORTHEAST...WITH BEST INSTABILITY AS YOU GO SOUTHWEST. THINK
THE BEST THREAT WILL BE ACROSS SOUTHWEST MINNESOTA CLOSEST TO THE
BEST FORCING...BUT GIVEN INSTABILITY TO THE SOUTHWEST...AND SOME OF
THE HI RES MODELS SHOWING CONVECTION FIRING IN OUR WEST...WILL KEEP
CHANCE POPS ACROSS THE WHOLE CWA. CONFIDENCE IS TOO LOW IN PLACEMENT
AND TIMING TO WARRANT ANY LIKELY POPS AT THIS TIME. ELEVATED
INSTABILITY AROUND 1000 J/KG TONIGHT WOULD SUGGEST A PRETTY GOOD
LIGHTNING THREAT WITH ANYTHING THAT DOES FORM TONIGHT...HOWEVER
SEVERE THREAT SHOULD REMAIN PRETTY LOW...WITH THE ELEVATED NATURE
LIMITING WIND THREAT...AND CAPE PROBABLY TOO LOW FOR MUCH OF A HAIL
THREAT. LOWS WILL BE MILDER TONIGHT...GENERALLY LOW AND MID 60S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 415 AM CDT SUN AUG 4 2013
FOR MONDAY...A COLD FRONT DROPS ACROSS THE REGION EARLY IN THE
DAY...AND OTHER THAN A SLIGHT CHANCE OF POPS IN THE SOUTH AND EAST
EARLY THINK THAT THE REMAINDER OF THE DAY WILL BE DRY IN
SUBSIDENCE/DRYING BEHIND AN EXITING SHORTWAVE. ONLY WEAK COLD AIR
ADVECTION BEHIND THE FRONT...AND WITH MORE SUN THAN TODAY
TEMPERATURES WILL WARM INTO THE UPPER 70S TO MID 80S ACROSS THE AREA
BY AFTERNOON. MOSTLY CLEAR SKIES WILL RULE FOR THE FIRST HALF OF
MONDAY NIGHT...BEFORE CLOUDS BEGIN TO INCREASE IN THE WEST THE
LATTER HALF OF THE NIGHT WITH MID LEVEL WARM AIR ADVECTION. CANNOT
RULE OUT THAT ISOLATED THUNDERSTORMS COULD MAKE IT INTO OUR FAR WEST
BY EARLY TUESDAY MORNING WITH THETA E ADVECTION ON A DEVELOPING LOW
LEVEL JET THROUGH WESTERN SOUTH DAKOTA. LOWS ON MONDAY NIGHT LOOKING
TO BE IN THE UPPER 50S TO LOWER 60S.
ANOTHER COLD FRONT ENCROACHES ON OUR AREA BY TUESDAY AFTERNOON...AND
MAY HAVE BETTER CHANCE OF THUNDERSTORMS ACROSS THE AREA WITH
INCREASING 850 MB THETA E ADVECTION AND INCREASING INSTABILITY OUT
AHEAD OF THE SYSTEM...WITH UPPER LEVEL SUPPORT AS A SHORTWAVE TRACKS
OVER THE AREA. THEIR DOES APPEAR TO BE ENOUGH CAPE AND SHEAR IN OUR
SOUTH AND WEST IN THE AFTERNOON THAT SEVERE STORMS WOULD BE
POSSIBLE. THERMAL PROFILES WARM JUST A BIT OUT AHEAD OF THE
FRONT...THOUGH HIGHS WILL BE DEPENDENT ON TIMING AND EVOLUTION OF
CONVECTION...BUT POTENTIALLY WILL REACH THE UPPER 70S TO MID 80S.
THE FRONTAL BOUNDARY WILL FINALLY PULL ACROSS THE AREA ON TUESDAY
EVENING WITH ANY CONVECTION ENDING FROM WEST TO EAST.
IN THE EXTENDED...WEDNESDAY THROUGH SATURDAY...MODELS IN DECENT
AGREEMENT ON THE DEVELOPMENT OF A CLOSED UPPER LEVEL LOW OVER
CENTRAL CANADA FOR MIDWEEK. THIS FEATURE WILL THEN SLOWLY MIGRATE TO
THE NORTHERN GREAT LAKES REGION BY THE END OF THE WEEK. THIS WILL
KEEP OUR AREA IN A NORTHWESTERLY UPPER LEVEL FLOW WITH BELOW NORMAL
TEMPERATURES THROUGH THE PERIOD. DOES NOT APPEAR TO BE ANY
OUTSTANDING CHANCES OF PRECIPITATION THROUGH THE EXTENDED...THOUGH
THE BEST CHANCE WOULD LOOK TO BE IN THE THURSDAY TO THURSDAY NIGHT
TIME FRAME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 644 AM CDT SUN AUG 4 2013
AREA OF SHOWERS AND EMBEDDED THUNDER MOVING EAST ACROSS THE CWA THIS
MORNING. THINK IT WILL CONTINUE TO WEAKEN AND DISSIPATE AS IT MOVES
INTO THE DRYER AND MORE STABLE AIR IN THE EAST. A FEW SHOWERS MAY
MAKE IT TO INTERSTATE 29 BETWEEN 8 AM AND 11 AM...BUT SHOULD
DISSIPATE AFTER THEN. NOT EXPECTING ANY LIGHTNING TO IMPACT THE TAF
SITES WITH THIS ACTIVITY. TONIGHT...WE MAY SEE ANOTHER ROUND OF
STORMS MOVE THROUGH FROM NORTHWEST TO SOUTHEAST. CONFIDENCE IN
COVERAGE AND TIMING IS CURRENTLY TOO LOW TO PUT A MENTION IN THE
TAFS. GUIDANCE IS SUGGESTING WE COULD SEE SOME MVFR STRATUS MOVE IN
AHEAD OF THE COLD FRONT TONIGHT. HOWEVER NOT COMPLETELY SOLD ON THAT
HAPPENING...SO WILL KEEP THE TAF VFR FOR THE TIME BEING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHENARD
LONG TERM...JM
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
416 AM CDT SUN AUG 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT SUN AUG 4 2013
MODELS STRUGGLING WITH ONGOING ACTIVITY ACROSS CENTRAL SOUTH DAKOTA
WHICH HAS DEVELOPED WITH AN INCREASING LOW LEVEL JET AND MID LEVEL
WAVE. DRY AIR TO THE EAST AND MINIMAL INSTABILITY IS EXPECTED TO
CAUSE A DOWNWARD TREND IN THIS CONVECTION AS IT ENTERS OUR CWA. OF
ALL THE GUIDANCE...SEEMS LIKE HRRR IS CLOSEST TO REALITY...WITH THE
0Z ECMWF ALSO NOT TOO BAD. BOTH OF THESE MODELS SUGGEST ACTIVITY
DOES INDEED WEAKEN AND DISSIPATE AS IT PUSHES EAST. HAVE HIGH CHANCE
TO LIKELY POPS THIS MORNING WEST OF THE JAMES RIVER...FROM ABOUT 10Z
TO 15Z. NOTHING SEVERE BUT WOULD EXPECT AT LEAST SOME LIGHTNING
ACTIVITY WITH THE STORMS. SHOWERS COULD MAKE IT AS FAR EAST AS
INTERSTATE 29 BY 13Z...BUT NOT REAL CONFIDENT IT WILL HOLD TOGETHER
EVEN THAT FAR...SO WILL ONLY GO SLIGHT CHANCE POPS. PLUS GIVEN THE
EXPECTED WEAKENING STATE...AND LACK OF INSTABILITY...PROBABLY WILL
NOT BE ANY LIGHTNING WITH ANYTHING THAT DOES MANAGE TO GET EAST OF
THE JAMES RIVER. TEND TO THINK WE SEE A LULL IN THE ACTIVITY DURING
THE AFTERNOON HOURS. BUT GIVEN WEAK FORCING...MID LEVEL MOISTURE
PRESENT...ONGOING ACTIVITY CONTINUING TO DEVELOP OVER NORTHWEST
SOUTH DAKOTA...AND THE GENERALLY LOW PREDICTABILITY OF THE
PATTERN...WILL KEEP A LOW CHANCE POPS IN THE WEST THROUGH THE
DAY...WITH SLIGHT CHANCES TO INTERSTATE 29. DAY SHIFT MAY END UP
BEING ABLE TO REMOVE THESE IF IT BECOMES MORE APPARENT DURING THE
MORNING THAT WE SEE A LULL IN THE ACTION. HIGHS TODAY ARE TRICKY AND
DEPENDENT ON REMNANT CLOUD COVER. THINK IT PROBABLY STAYS MOSTLY
CLOUDY FOR MUCH OF THE DAY. DID BUMP HIGHS UP SOME WITH SOME OF THE
NEWER GUIDANCE COMING IN A BIT WARMER...BUT GIVEN CLOUD COVER
CONCERNS DID NOT WANT TO GO TOO WARM...AND WENT WITH MAINLY MID AND
UPPER 70S. IF WE SOMEHOW ARE ABLE TO GET MORE SUN TODAY...HIGHS
WOULD END UP SEVERAL DEGREES WARMER. SO ANOTHER THING THE DAY SHIFT
WILL HAVE TO MONITOR.
UNFORTUNATELY...FORECAST CONFIDENCE DOES NOT INCREASE TONIGHT. THE
CORE OF THE UPPER LEVEL SUPPORT WILL DIVE SOUTHEAST ACROSS
MINNESOTA. SEEMS LIKE A GOOD BET THAT WE SEE ANOTHER ROUND OF
NOCTURNAL CONVECTION ACROSS THE NORTHERN PLAINS. BEST FORCING IS TO
THE NORTHEAST...WITH BEST INSTABILITY AS YOU GO SOUTHWEST. THINK
THE BEST THREAT WILL BE ACROSS SOUTHWEST MINNESOTA CLOSEST TO THE
BEST FORCING...BUT GIVEN INSTABILITY TO THE SOUTHWEST...AND SOME OF
THE HI RES MODELS SHOWING CONVECTION FIRING IN OUR WEST...WILL KEEP
CHANCE POPS ACROSS THE WHOLE CWA. CONFIDENCE IS TOO LOW IN PLACEMENT
AND TIMING TO WARRANT ANY LIKELY POPS AT THIS TIME. ELEVATED
INSTABILITY AROUND 1000 J/KG TONIGHT WOULD SUGGEST A PRETTY GOOD
LIGHTNING THREAT WITH ANYTHING THAT DOES FORM TONIGHT...HOWEVER
SEVERE THREAT SHOULD REMAIN PRETTY LOW...WITH THE ELEVATED NATURE
LIMITING WIND THREAT...AND CAPE PROBABLY TOO LOW FOR MUCH OF A HAIL
THREAT. LOWS WILL BE MILDER TONIGHT...GENERALLY LOW AND MID 60S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 415 AM CDT SUN AUG 4 2013
FOR MONDAY...A COLD FRONT DROPS ACROSS THE REGION EARLY IN THE
DAY...AND OTHER THAN A SLIGHT CHANCE OF POPS IN THE SOUTH AND EAST
EARLY THINK THAT THE REMAINDER OF THE DAY WILL BE DRY IN
SUBSIDENCE/DRYING BEHIND AN EXITING SHORTWAVE. ONLY WEAK COLD AIR
ADVECTION BEHIND THE FRONT...AND WITH MORE SUN THAN TODAY
TEMPERATURES WILL WARM INTO THE UPPER 70S TO MID 80S ACROSS THE AREA
BY AFTERNOON. MOSTLY CLEAR SKIES WILL RULE FOR THE FIRST HALF OF
MONDAY NIGHT...BEFORE CLOUDS BEGIN TO INCREASE IN THE WEST THE
LATTER HALF OF THE NIGHT WITH MID LEVEL WARM AIR ADVECTION. CANNOT
RULE OUT THAT ISOLATED THUNDERSTORMS COULD MAKE IT INTO OUR FAR WEST
BY EARLY TUESDAY MORNING WITH THETA E ADVECTION ON A DEVELOPING LOW
LEVEL JET THROUGH WESTERN SOUTH DAKOTA. LOWS ON MONDAY NIGHT LOOKING
TO BE IN THE UPPER 50S TO LOWER 60S.
ANOTHER COLD FRONT ENCROACHES ON OUR AREA BY TUESDAY AFTERNOON...AND
MAY HAVE BETTER CHANCE OF THUNDERSTORMS ACROSS THE AREA WITH
INCREASING 850 MB THETA E ADVECTION AND INCREASING INSTABILITY OUT
AHEAD OF THE SYSTEM...WITH UPPER LEVEL SUPPORT AS A SHORTWAVE TRACKS
OVER THE AREA. THEIR DOES APPEAR TO BE ENOUGH CAPE AND SHEAR IN OUR
SOUTH AND WEST IN THE AFTERNOON THAT SEVERE STORMS WOULD BE
POSSIBLE. THERMAL PROFILES WARM JUST A BIT OUT AHEAD OF THE
FRONT...THOUGH HIGHS WILL BE DEPENDENT ON TIMING AND EVOLUTION OF
CONVECTION...BUT POTENTIALLY WILL REACH THE UPPER 70S TO MID 80S.
THE FRONTAL BOUNDARY WILL FINALLY PULL ACROSS THE AREA ON TUESDAY
EVENING WITH ANY CONVECTION ENDING FROM WEST TO EAST.
IN THE EXTENDED...WEDNESDAY THROUGH SATURDAY...MODELS IN DECENT
AGREEMENT ON THE DEVELOPMENT OF A CLOSED UPPER LEVEL LOW OVER
CENTRAL CANADA FOR MIDWEEK. THIS FEATURE WILL THEN SLOWLY MIGRATE TO
THE NORTHERN GREAT LAKES REGION BY THE END OF THE WEEK. THIS WILL
KEEP OUR AREA IN A NORTHWESTERLY UPPER LEVEL FLOW WITH BELOW NORMAL
TEMPERATURES THROUGH THE PERIOD. DOES NOT APPEAR TO BE ANY
OUTSTANDING CHANCES OF PRECIPITATION THROUGH THE EXTENDED...THOUGH
THE BEST CHANCE WOULD LOOK TO BE IN THE THURSDAY TO THURSDAY NIGHT
TIME FRAME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1055 PM CDT SAT AUG 3 2013
LOOKING FOR CONVECTION OVER THE WESTERN HIGH PLAINS THIS EVENING TO
SPREAD EAST ACROSS SD THROUGH THE DAY SUNDAY. MAIN QUESTION WILL BE
HOW MUCH CONTINUED ADVECTION OF DRY LOW LEVEL AIR FROM THE EAST TO
SOUTHEAST WILL HAMPER EASTWARD EXPANSION OF THE PRECIPITATION. WILL
KEEP A MENTION OF SHOWERS AT KHON FOR THE LATE MORNING THROUGH MID
AFTERNOON...BUT LATEST MODELS SEEM TO INDICATE BETTER CHANCE OF DRY
AIR WINNING OUT AT KFSD/KSUX WITH BETTER UPPER LEVEL SUPPORT FOR
PRECIPITATION SPLITTING AROUND THOSE LOCATIONS. WITH THIS LEVEL OF
UNCERTAINTY INTRODUCED BY EVENING MODEL RUNS...WILL KEEP KFSD/KSUX
FREE OF PRECIP WITH THIS ISSUANCE. INSTABILITY...EVEN ELEVATED...
PRETTY MEAGER FOR START OF PRECIPITATION AT KHON...SO WILL CONTINUE
WITH JUST SHOWER MENTION FOR NOW. INSTABILITY DOES RAMP UP LATER IN
THE AFTERNOON/EVENING...SO THUNDER POTENTIAL COULD INCREASE LATER IN
THE FORECAST PERIOD...BUT CONFIDENCE IN TIMING NOT HIGH ENOUGH TO
INCLUDE AT THIS TIME. PERIODS OF MVFR VISIBILITIES COULD ACCOMPANY
PRECIPITATION...BUT VFR CONDITIONS EXPECTED TO DOMINATE THROUGH THE
TAF PERIOD MOST AREAS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHENARD
LONG TERM...JM
AVIATION...JH
SEE THE 12Z AVIATION FORECAST DISCUSSION BELOW.
40
&&
.AVIATION...
DEEPER LAYER MOISTURE AS SEEN BY THE WATER VAPOR AND THE 00Z LCH
SOUNDING WILL HELP BRING SLIGHTLY BETTER CHANCES FOR SHOWERS
TODAY. COULD NOT RULE OUT THUNDER BUT WENT WITH VCSH FOR NOW FOR
THE BIG AIRPORTS TO THE COAST. OUTSIDE OF THE RAIN CHANCES...WINDS
ARE THE MAIN PROBLEM OF THE DAY. WENT MAINLY WITH PERSISTENCE IN
TRYING TO TIME THE SEABREEZE. A DECENT THERMAL GRADIENT WILL BE
THE MAIN DRIVER FOR THE SLIGHTLY HIGHER WIND SPEEDS FOR SOME
LOCATIONS THIS AFTERNOON AND EARLY EVENING. OTHERWISE...VFR WITH
A CHANCE OF A SCATTERED MVFR DECK BEFORE 15Z TODAY.
40
&&
.PREV DISCUSSION... /ISSUED 345 AM CDT SUN AUG 4 2013/
DISCUSSION...
A VERY WARM START TO THE MORNING AS MOST SITES ARE STILL IN THE
LOWER 80S. HEAT INDEX VALUES AT 3 AM RANGED FROM THE UPPER 80S TO
THE UPPER 90S (97 - KGLS). SURFACE HIGH PRESSURE WAS LOCATED OVER
THE CENTRAL GULF OF MEXICO WITH LOWER PRESSURE OVER SOUTHWEST
TEXAS. 850 MB TEMPS ARE A DEGREE COOLER THAN LAST NIGHT AND DEEPER
850 MB MOISTURE WAS OVER SOUTHWEST LOUISIANA. A 700 MB HIGH WAS
CENTERED OVER EASTERN OKLAHOMA AND DEEPER 700 MB MOISTURE WAS
AGAIN OVER SOUTHWEST LOUISIANA. 700 MB TEMPS HAD COOLED FURTHER AT
BOTH KLCH AND KSHV. A STRONG UPPER LEVEL HIGH REMAINS NEARLY
STATIONARY OVER WEST CENTRAL TEXAS. FCST SOUNDINGS FOR THIS AFTN
SHOW PW VALUES PEAKING NEAR 2.00 INCHES WITH K INDEX VALUES FROM
34 TO 38. THE HRRR... RAP AND 4 KM WRF ALL BRING SHRA/TSRA INTO SE
TX LATE THIS MORNING INTO THE AFTN. THE DEEPER MOISTURE TO THE
EAST WILL MOVE INTO SE TX LATER THIS MORNING. SHRA/TSRA ARE
EXPECTED TO DEVELOP THIS MORNING ONCE HEATING COMMENCES. STILL A
GREAT DEAL OF CONCERN THAT THE MAMMOTH UPPER RIDGE WILL IMPART
SUBSIDENCE AND THIS COULD LIMIT DEVELOPMENT. A FEW MORE CLOUDS AND
DEEPER MOISTURE WILL HINDER HEATING SO SHAVED A FEW DEGREES FROM
YESTERDAYS VALUES.
UPPER LEVEL RIDGING WILL REMAIN IN CONTROL FOR THE REST OF THE
WEEK. STILL SOME MOISTURE AROUND ON MONDAY BUT AS THE CENTER OF
THE UPPER RIDGE NUDGES CLOSER...FEEL SUBSIDENCE WILL END ANY
POTENTIAL FOR SHOWERS. 850 MB TEMPS SLOWLY WARM THROUGH THURSDAY
AND 850 MB WINDS VEER TO THE SOUTHWEST. TUE-THU CONTINUE TO LOOK
VERY WARM WITH 100 DEGREE HEAT RETURNING OR CONTINUING FOR MOST OF
THE AREA. HEAT INDEX VALUES LOOK TO GET NEAR ADVISORY CRITERIA
MID WEEK.
850 MB WINDS TURN TO THE SOUTHEAST ON FRIDAY AND THE UPPER RIDGE
RETREATS EVER SO SLIGHTLY. MOISTURE LEVELS WILL BEGIN TO DEEPEN SO
TRENDED MAX TEMPS SLIGHTLY COOLER FOR FRIDAY. A WEAK DISTURBANCE
MOVING INTO THE REGION FROM THE EAST WILL BRING THE AREA A SLIGHT
CHANCE OF RAIN ON SAT/SUN. THE RIDGE STILL LOOKS TOO STRONG AND
THE DISTURBANCE WILL PROBABLY BE SHUNTED SOUTH OF THE AREA. THAT
SAID...DEEPER MSTR WILL STILL FILTER INTO SE TX NEXT WEEKEND WITH
SLIGHTLY COOLER TEMPS AND A SLIGHT CHANCE OF RAIN. 43
MARINE...
ONSHORE WINDS EXPECTED TO CONTINUE WITH THE SURFACE RIDGE EXTENDING
ACROSS THE NORTHERN GULF OF MEXICO. THE THERMAL GRADIENT WILL HELP
TO GENERATE A DAILY CYCLE OF LIGHTER WINDS IN THE LATE MORNING TO
EARLY AFTERNOON AND MODERATE WINDS FROM THE LATE AFTERNOON THROUGH
THE EVENING. WITH A DEEPER LAYER OF MOISTURE AND A WEAK BOUNDARY
ABOVE THE SURFACE...DO EXPECT ISOLATED SHOWERS THIS MORNING.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 99 76 100 76 101 / 10 10 10 10 0
HOUSTON (IAH) 96 77 97 77 99 / 20 10 10 10 0
GALVESTON (GLS) 92 83 93 82 92 / 20 10 10 10 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
345 AM CDT SUN AUG 4 2013
.DISCUSSION...
A VERY WARM START TO THE MORNING AS MOST SITES ARE STILL IN THE
LOWER 80S. HEAT INDEX VALUES AT 3 AM RANGED FROM THE UPPER 80S TO
THE UPPER 90S (97 - KGLS). SURFACE HIGH PRESSURE WAS LOCATED OVER
THE CENTRAL GULF OF MEXICO WITH LOWER PRESSURE OVER SOUTHWEST
TEXAS. 850 MB TEMPS ARE A DEGREE COOLER THAN LAST NIGHT AND DEEPER
850 MB MOISTURE WAS OVER SOUTHWEST LOUISIANA. A 700 MB HIGH WAS
CENTERED OVER EASTERN OKLAHOMA AND DEEPER 700 MB MOISTURE WAS
AGAIN OVER SOUTHWEST LOUISIANA. 700 MB TEMPS HAD COOLED FURTHER AT
BOTH KLCH AND KSHV. A STRONG UPPER LEVEL HIGH REMAINS NEARLY
STATIONARY OVER WEST CENTRAL TEXAS. FCST SOUNDINGS FOR THIS AFTN
SHOW PW VALUES PEAKING NEAR 2.00 INCHES WITH K INDEX VALUES FROM
34 TO 38. THE HRRR... RAP AND 4 KM WRF ALL BRING SHRA/TSRA INTO SE
TX LATE THIS MORNING INTO THE AFTN. THE DEEPER MOISTURE TO THE
EAST WILL MOVE INTO SE TX LATER THIS MORNING. SHRA/TSRA ARE
EXPECTED TO DEVELOP THIS MORNING ONCE HEATING COMMENCES. STILL A
GREAT DEAL OF CONCERN THAT THE MAMMOTH UPPER RIDGE WILL IMPART
SUBSIDENCE AND THIS COULD LIMIT DEVELOPMENT. A FEW MORE CLOUDS AND
DEEPER MOISTURE WILL HINDER HEATING SO SHAVED A FEW DEGREES FROM
YESTERDAYS VALUES.
UPPER LEVEL RIDGING WILL REMAIN IN CONTROL FOR THE REST OF THE
WEEK. STILL SOME MOISTURE AROUND ON MONDAY BUT AS THE CENTER OF
THE UPPER RIDGE NUDGES CLOSER...FEEL SUBSIDENCE WILL END ANY
POTENTIAL FOR SHOWERS. 850 MB TEMPS SLOWLY WARM THROUGH THURSDAY
AND 850 MB WINDS VEER TO THE SOUTHWEST. TUE-THU CONTINUE TO LOOK
VERY WARM WITH 100 DEGREE HEAT RETURNING OR CONTINUING FOR MOST OF
THE AREA. HEAT INDEX VALUES LOOK TO GET NEAR ADVISORY CRITERIA
MID WEEK.
850 MB WINDS TURN TO THE SOUTHEAST ON FRIDAY AND THE UPPER RIDGE
RETREATS EVER SO SLIGHTLY. MOISTURE LEVELS WILL BEGIN TO DEEPEN SO
TRENDED MAX TEMPS SLIGHTLY COOLER FOR FRIDAY. A WEAK DISTURBANCE
MOVING INTO THE REGION FROM THE EAST WILL BRING THE AREA A SLIGHT
CHANCE OF RAIN ON SAT/SUN. THE RIDGE STILL LOOKS TOO STRONG AND
THE DISTURBANCE WILL PROBABLY BE SHUNTED SOUTH OF THE AREA. THAT
SAID...DEEPER MSTR WILL STILL FILTER INTO SE TX NEXT WEEKEND WITH
SLIGHTLY COOLER TEMPS AND A SLIGHT CHANCE OF RAIN. 43
&&
.MARINE...
ONSHORE WINDS EXPECTED TO CONTINUE WITH THE SURFACE RIDGE EXTENDING
ACROSS THE NORTHERN GULF OF MEXICO. THE THERMAL GRADIENT WILL HELP
TO GENERATE A DAILY CYCLE OF LIGHTER WINDS IN THE LATE MORNING TO
EARLY AFTERNOON AND MODERATE WINDS FROM THE LATE AFTERNOON THROUGH
THE EVENING. WITH A DEEPER LAYER OF MOISTURE AND A WEAK BOUNDARY
ABOVE THE SURFACE...DO EXPECT ISOLATED SHOWERS THIS MORNING.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 99 76 100 76 101 / 10 10 10 10 0
HOUSTON (IAH) 96 77 97 77 99 / 20 10 10 10 0
GALVESTON (GLS) 92 83 93 82 92 / 20 10 10 10 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
912 PM CDT MON AUG 5 2013
.UPDATE...TONIGHT
ISSUED AT 912 PM CDT MON AUG 5 2013
DIURNAL CONVECTION HAS GENERALLY COME TO AN END ACROSS THE REGION
WITH SOME TRAILING SHOWERS LINGERING IN SOUTHWEST WISCONSIN ALONG
A WEAK SURFACE TROUGH/COLD FRONT. MID LEVEL SUBSIDENCE NOTED ON
WATER VAPOR HAS ALLOWED FOR SKIES TO CLEAR OUT ACROSS MUCH OF
MINNESOTA AND IOWA. IT WAS LOOKING LIKE WISCONSIN WOULD GET IN ON
THE CLEARING AS WELL...BUT A LOW LEVEL STRATUS DECK GOT STUCK
UNDER A SHALLOW INVERSION AROUND 1500FT AND HAS STALLED OUT FROM
FAR EASTERN MINNESOTA/IOWA ON INTO WESTERN WISCONSIN. WITH THE LOW
LEVEL SURGE OF DRIER AIR APPEARING TO HAVE STALLED OUT TO THE
WEST...AM BECOMING MORE CONCERNED FOR THE POTENTIAL OF DENSE FOG
TONIGHT. THE MAIN UNCERTAINTY IS WITH WHETHER THIS WILL JUST STAY
AS A LOW LEVEL STRATUS DECK BECAUSE OF SOME
STRONGER...10KT...WINDS AT THE INVERSION LEVEL OR IF THE
SATURATION WILL JUST CONTINUE ON DOWN TO THE GROUND OVERNIGHT.
SOME REPORTS FROM NORTHEAST IOWA HAVE BEEN THAT VISIBILITY HAS
DROPPED DOWN TO AN EIGHTH OF A MILE IN SPOTS IN EASTERN FILLMORE
COUNTY AND NORTHERN WINNESHIEK COUNTIES. WITH SUCH HIGH MOISTURE
ALREADY IN PLACE...AM LEANING MORE ALONG THE FOG SOLUTION RATHER
THAN JUST STRATUS. IF QUARTER MILE VISIBILITIES BECOME MORE
WIDESPREAD...MAY HAVE TO DO A DENSE FOG ADVISORY OVERNIGHT.
ALSO...DESPITE LOW LEVEL FORCING LOOKING WEAK...ALSO CAN NOT RULE
OUT SOME DRIZZLE WITH THESE LOW CEILINGS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 310 PM CDT MON AUG 5 2013
THE NEXT 24 TO 36 HOURS WILL FEATURE A MORE ACTIVE PERIOD WITH A
FEW WEATHER SYSTEMS TO CONTEND WITH INCLUDING PRECIPITATION
CHANCES THIS EVENING...FOG OVERNIGHT...AND THEN SEVERE THREAT
TUESDAY AFTERNOON/EVENING.
LATEST WATER VAPOR COMBINED WITH RAP 500MB HEIGHTS SHOW BROAD
NORTHWEST FLOW EAST OF THE ROCKIES...WITH NUMEROUS EMBEDDED
SHORTWAVE TROUGHS. ONE CURRENTLY MOVING THROUGH
MINNESOTA/IOWA...WHILE UPSTREAM ACROSS ALBERTA SITS A MORE VIGOROUS
WAVE. FINALLY...A CLOSED POLAR VORTEX RESIDES NEAR HUDSON BAY.
FOR THIS EVENING INTO TONIGHT...WILL CARRY A SLIGHT CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS UNTIL UPPER LEVEL SHORTWAVE
COMPLETELY EXITS THE AREA. DESPITE SURFACE TROUGH LAGGING
BEHIND...AND BUILDING INSTABILITY WITH CLEARING SKIES...SUBSIDENCE
IN THE WAKE OF THE UPPER LEVEL SHORTWAVE AND SOME LOW TO MID LEVEL
DRYING SHOULD PRECLUDE THE DEVELOPMENT OF ADDITIONAL SHOWERS/STORMS.
HAVE ADDED PATCHY TO AREAS OF FOG FOR PARTS OF WISCONSIN...INCLUDING
THE MS AND WISCONSIN RIVER VALLEYS OVERNIGHT AS A WEAK SURFACE
HIGH BUILDS IN THE WAKE OF THE DEPARTING SYSTEM AND AHEAD OF THE
APPROACHING COLD FRONT. NICE SETUP WITH TODAY/S COOL...CLOUDY
CONDITIONS AND RECENT RAINFALL...THEN CLEARING SKIES LATE THIS
EVENING. SURFACE WIND FIELD DROPS TO 5 KTS OR LESS...AND SOUNDINGS
SHOW DECENT BOUNDARY LAYER SATURATION THOUGH TRY TO SHOW A STIFF
BREEZE AT ABOUT 500 FT. COULD BE A MORE WIDESPREAD FOG SCENARIO
INSTEAD OF JUST THE RIVER VALLEYS...SOMETHING TO WATCH THIS
EVENING.
THE ALBERTA SHORTWAVE TROUGH THEN TAKES AIM ON THE AREA...AND WILL
BE THE FOCUS FOR PUSHING THROUGH A SURFACE COLD FRONT TUESDAY
EVENING. BUILDING INSTABILITY DURING THE DAY IS SOMEWHAT CONDITIONAL
ON AN EARLY MORNING MCS EXPECTED WELL TO OUR WEST...BUT BY MID
AFTERNOON...MUCAPE BETWEEN 1500 AND 2000 J/KG COULD BE REALIZED. THE
SHEAR ENVIRONMENT IS MORE THAN SUFFICIENT FOR SEVERE STORMS AS 250
MB JET MAX OVERHEAD PUTS 40 TO 50 KTS OF EFFECTIVE SHEAR ACROSS MUCH
OF THE AREA...AND THE LOW-LEVELS HAVE FAVORABLE LAPSE RATES.
HODOGRAPHS SHOW MODEST LOOPING. OVERALL...IF INSTABILITY CONDITIONS
ARE MET...ENVISION STORM MODE TO FAVOR RIGHT MOVING CLUSTER OF
CELLS EVOLVING INTO BOWING SEGMENTS WITH THE MAIN THREAT LARGE
HAIL AND DAMAGING WINDS. 0-1 KM SHEAR ENVIRONMENT IS
UNIDIRECTIONAL SO NOT EXPECTING A FAVORABLE TORNADO ENVIRONMENT
HOWEVER WITH THAT SAID...ANY LINGERING SURFACE BOUNDARIES COULD
COMPLICATE THAT.
MODEL AGREEMENT ON FRONTAL TIMING IS HIGHER WITH THE 05.12Z
GUIDANCE...WHICH ADDS CONFIDENCE TO THE LATE AFTERNOON AND EVENING
PRECIPITATION CHANCES. THE NAM REMAINS A FASTER OUTLIER WHILE THE
GEM/GFS/ECMWF ARE CONSISTENT WITH A 00 TO 06Z PASSAGE. EARLIER
FORECAST TIMING FOR POPS LOOK GOOD SO HAVE CARRIED SIMILAR
THINKING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 310 PM CDT MON AUG 5 2013
THE BIG STORY IN THE LONG TERM WILL BE A CONTINUATION OF THE
UNSEASONABLY COOL WEATHER PATTERN AS THE MAIN POLAR VORTEX / CLOSED
UPPER LOW WOBBLES ACROSS SOUTHERN CANADA. OUTSIDE OF SCATTERED
DAYTIME CUMULUS FIELD ACROSS WISCONSIN WEDNESDAY...HIGH PRESSURE
DOMINATES WITH PLEASANT CONDITIONS. HIGHS LOWER TO MIDDLE 70S.
ANOTHER SIMILAR DAY THURSDAY...THOUGH BY EVENING INTO THE NIGHT THE
CLOSED UPPER LOW WOBBLES FURTHER TO THE SOUTH AS ANOTHER PIECE OF
ENERGY ROUNDS THE BASE. THIS TRIES TO DRIVE A SURFACE COLD FRONT
WITH SHOWERS AND THUNDERSTORMS ACROSS CENTRAL MINNESOTA INTO
WISCONSIN. HOWEVER...BETTER DYNAMICS AND MOISTURE TRANSPORT REMAIN
IN THE WEST AND NORTH FORECAST...AND THE FRONT WASHES OUT BEFORE
MAKING IT VERY FAR INTO THE FORECAST AREA. WILL CONTINUE SLIGHT
CHANCES IN THE NORTHWEST WHILE THE REST OF THE AREA WILL LIKELY ONLY
SEE INCREASED CLOUD COVER.
IN THE WAKE OF THIS SHORTWAVE TROUGH...A REINFORCING SHOT OF COOLER
AIR SURGES IN AS SEEN BY 850 MB TEMPERATURES FRIDAY AND SATURDAY
DROPPING TO THE 8 TO 10C RANGE. HIGHS IN THE 70S AND OVERNIGHT LOWS
COULD DIP INTO THE UPPER 40S TO LOWER 50S...ESPECIALLY FOR THE
TYPICAL COOLER SPOTS OF CENTRAL WISCONSIN. DEPENDING ON THE HIGH
PRESSURE AXIS...COULD SEE A FEW MORNINGS OF RIVER VALLEY FOG AS
WELL. OVERALL...VERY NICE CONDITIONS FOR EARLY/MID AUGUST POSSIBLE
ACROSS THE ENTIRE UPPER MIDWEST FROM FRIDAY INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 651 PM CDT MON AUG 5 2013
MVFR 1-2KFT DECK WILL CONTINUE TO TRACK TO THE EAST THIS EVENING
AND HAS ALREADY CLEARED RST WITH AN ARRIVAL INTO LSE BETWEEN 2/3Z.
WITH SKIES CLEARING...WINDS REMAINING ON THE LIGHT SIDE TONIGHT
AND SOME RECENT RAINFALL WETTING THE GROUND...EXPECT TO SEE SOME
FOG DEVELOP. THE MAIN LIMITING FACTOR IS WITH WINDS JUST ABOVE THE
SURFACE AND HOW MUCH THAT WILL AFFECT THE FOG FORMATION. WITH ALL
OF THE SHORT TERM GUIDANCE ALSO FORECASTING SOME IFR FOG
CONDITIONS AT BOTH LSE/RST...HAVE ADDED SOME PREVAILING IFR
CONDITIONS OVERNIGHT INTO EARLY TOMORROW MORNING. IF THE LOW LEVEL
WINDS REMAIN LIGHT...THERE COULD BE SOME 1/4SM VISIBILITIES THAT
OCCUR. INTO TOMORROW AFTERNOON...SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE...PARTICULARLY TOWARD LATE AFTERNOON AND THE EVENING
AHEAD OF A COLD FRONT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...ZT
LONG TERM....ZT
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
651 PM CDT MON AUG 5 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 310 PM CDT MON AUG 5 2013
THE NEXT 24 TO 36 HOURS WILL FEATURE A MORE ACTIVE PERIOD WITH A
FEW WEATHER SYSTEMS TO CONTEND WITH INCLUDING PRECIPITATION
CHANCES THIS EVENING...FOG OVERNIGHT...AND THEN SEVERE THREAT
TUESDAY AFTERNOON/EVENING.
LATEST WATER VAPOR COMBINED WITH RAP 500MB HEIGHTS SHOW BROAD
NORTHWEST FLOW EAST OF THE ROCKIES...WITH NUMEROUS EMBEDDED
SHORTWAVE TROUGHS. ONE CURRENTLY MOVING THROUGH
MINNESOTA/IOWA...WHILE UPSTREAM ACROSS ALBERTA SITS A MORE VIGOROUS
WAVE. FINALLY...A CLOSED POLAR VORTEX RESIDES NEAR HUDSON BAY.
FOR THIS EVENING INTO TONIGHT...WILL CARRY A SLIGHT CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS UNTIL UPPER LEVEL SHORTWAVE
COMPLETELY EXITS THE AREA. DESPITE SURFACE TROUGH LAGGING
BEHIND...AND BUILDING INSTABILITY WITH CLEARING SKIES...SUBSIDENCE
IN THE WAKE OF THE UPPER LEVEL SHORTWAVE AND SOME LOW TO MID LEVEL
DRYING SHOULD PRECLUDE THE DEVELOPMENT OF ADDITIONAL SHOWERS/STORMS.
HAVE ADDED PATCHY TO AREAS OF FOG FOR PARTS OF WISCONSIN...INCLUDING
THE MS AND WISCONSIN RIVER VALLEYS OVERNIGHT AS A WEAK SURFACE
HIGH BUILDS IN THE WAKE OF THE DEPARTING SYSTEM AND AHEAD OF THE
APPROACHING COLD FRONT. NICE SETUP WITH TODAY/S COOL...CLOUDY
CONDITIONS AND RECENT RAINFALL...THEN CLEARING SKIES LATE THIS
EVENING. SURFACE WIND FIELD DROPS TO 5 KTS OR LESS...AND SOUNDINGS
SHOW DECENT BOUNDARY LAYER SATURATION THOUGH TRY TO SHOW A STIFF
BREEZE AT ABOUT 500 FT. COULD BE A MORE WIDESPREAD FOG SCENARIO
INSTEAD OF JUST THE RIVER VALLEYS...SOMETHING TO WATCH THIS
EVENING.
THE ALBERTA SHORTWAVE TROUGH THEN TAKES AIM ON THE AREA...AND WILL
BE THE FOCUS FOR PUSHING THROUGH A SURFACE COLD FRONT TUESDAY
EVENING. BUILDING INSTABILITY DURING THE DAY IS SOMEWHAT CONDITIONAL
ON AN EARLY MORNING MCS EXPECTED WELL TO OUR WEST...BUT BY MID
AFTERNOON...MUCAPE BETWEEN 1500 AND 2000 J/KG COULD BE REALIZED. THE
SHEAR ENVIRONMENT IS MORE THAN SUFFICIENT FOR SEVERE STORMS AS 250
MB JET MAX OVERHEAD PUTS 40 TO 50 KTS OF EFFECTIVE SHEAR ACROSS MUCH
OF THE AREA...AND THE LOW-LEVELS HAVE FAVORABLE LAPSE RATES.
HODOGRAPHS SHOW MODEST LOOPING. OVERALL...IF INSTABILITY CONDITIONS
ARE MET...ENVISION STORM MODE TO FAVOR RIGHT MOVING CLUSTER OF
CELLS EVOLVING INTO BOWING SEGMENTS WITH THE MAIN THREAT LARGE
HAIL AND DAMAGING WINDS. 0-1 KM SHEAR ENVIRONMENT IS
UNIDIRECTIONAL SO NOT EXPECTING A FAVORABLE TORNADO ENVIRONMENT
HOWEVER WITH THAT SAID...ANY LINGERING SURFACE BOUNDARIES COULD
COMPLICATE THAT.
MODEL AGREEMENT ON FRONTAL TIMING IS HIGHER WITH THE 05.12Z
GUIDANCE...WHICH ADDS CONFIDENCE TO THE LATE AFTERNOON AND EVENING
PRECIPITATION CHANCES. THE NAM REMAINS A FASTER OUTLIER WHILE THE
GEM/GFS/ECMWF ARE CONSISTENT WITH A 00 TO 06Z PASSAGE. EARLIER
FORECAST TIMING FOR POPS LOOK GOOD SO HAVE CARRIED SIMILAR
THINKING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 310 PM CDT MON AUG 5 2013
THE BIG STORY IN THE LONG TERM WILL BE A CONTINUATION OF THE
UNSEASONABLY COOL WEATHER PATTERN AS THE MAIN POLAR VORTEX / CLOSED
UPPER LOW WOBBLES ACROSS SOUTHERN CANADA. OUTSIDE OF SCATTERED
DAYTIME CUMULUS FIELD ACROSS WISCONSIN WEDNESDAY...HIGH PRESSURE
DOMINATES WITH PLEASANT CONDITIONS. HIGHS LOWER TO MIDDLE 70S.
ANOTHER SIMILAR DAY THURSDAY...THOUGH BY EVENING INTO THE NIGHT THE
CLOSED UPPER LOW WOBBLES FURTHER TO THE SOUTH AS ANOTHER PIECE OF
ENERGY ROUNDS THE BASE. THIS TRIES TO DRIVE A SURFACE COLD FRONT
WITH SHOWERS AND THUNDERSTORMS ACROSS CENTRAL MINNESOTA INTO
WISCONSIN. HOWEVER...BETTER DYNAMICS AND MOISTURE TRANSPORT REMAIN
IN THE WEST AND NORTH FORECAST...AND THE FRONT WASHES OUT BEFORE
MAKING IT VERY FAR INTO THE FORECAST AREA. WILL CONTINUE SLIGHT
CHANCES IN THE NORTHWEST WHILE THE REST OF THE AREA WILL LIKELY ONLY
SEE INCREASED CLOUD COVER.
IN THE WAKE OF THIS SHORTWAVE TROUGH...A REINFORCING SHOT OF COOLER
AIR SURGES IN AS SEEN BY 850 MB TEMPERATURES FRIDAY AND SATURDAY
DROPPING TO THE 8 TO 10C RANGE. HIGHS IN THE 70S AND OVERNIGHT LOWS
COULD DIP INTO THE UPPER 40S TO LOWER 50S...ESPECIALLY FOR THE
TYPICAL COOLER SPOTS OF CENTRAL WISCONSIN. DEPENDING ON THE HIGH
PRESSURE AXIS...COULD SEE A FEW MORNINGS OF RIVER VALLEY FOG AS
WELL. OVERALL...VERY NICE CONDITIONS FOR EARLY/MID AUGUST POSSIBLE
ACROSS THE ENTIRE UPPER MIDWEST FROM FRIDAY INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 651 PM CDT MON AUG 5 2013
MVFR 1-2KFT DECK WILL CONTINUE TO TRACK TO THE EAST THIS EVENING
AND HAS ALREADY CLEARED RST WITH AN ARRIVAL INTO LSE BETWEEN 2/3Z.
WITH SKIES CLEARING...WINDS REMAINING ON THE LIGHT SIDE TONIGHT
AND SOME RECENT RAINFALL WETTING THE GROUND...EXPECT TO SEE SOME
FOG DEVELOP. THE MAIN LIMITING FACTOR IS WITH WINDS JUST ABOVE THE
SURFACE AND HOW MUCH THAT WILL AFFECT THE FOG FORMATION. WITH ALL
OF THE SHORT TERM GUIDANCE ALSO FORECASTING SOME IFR FOG
CONDITIONS AT BOTH LSE/RST...HAVE ADDED SOME PREVAILING IFR
CONDITIONS OVERNIGHT INTO EARLY TOMORROW MORNING. IF THE LOW LEVEL
WINDS REMAIN LIGHT...THERE COULD BE SOME 1/4SM VISIBILITIES THAT
OCCUR. INTO TOMORROW AFTERNOON...SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE...PARTICULARLY TOWARD LATE AFTERNOON AND THE EVENING
AHEAD OF A COLD FRONT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ZT
LONG TERM....ZT
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1024 PM MDT SAT AUG 3 2013
.UPDATE...
ISSUED AT 708 PM MDT SAT AUG 3 2013
THUNDERSTORMS HAVE WEAKENED AND SO HAVE CANCELLED THE TORNADO
WATCH FOR THE SOUTHEAST WYOMING PLAINS. STILL SOME SHOWERS AND
STORMS OVER SOUTHEAST WYOMING EARLY THIS EVENING. THE ACTIVITY
HAS BEEN DECREASING IN COVERAGE AND INTENSITY AS IT TRIES TO
MOVE FURTHER EAST. THE ATMOSPHERE OVER THE PANHANDLE SHOULD
CONTINUE TO BE STABLE TONIGHT. LOW CLOUDS AND AREAS OF FOG WILL
BE LIKELY OVER THE EAST PART OF THE CWA TONIGHT WITH SOME
LOCATIONS ALREADY WITH LOW CLOUDS. IN A RECENT UPDATE...LOWERED
POPS OVER THE PANHANDLE FOR EARLY TONIGHT AND INCREASED CLOUD
COVER OVER THE EAST PART OF THE CWA.
UPDATE ISSUED AT 344 PM MDT SAT AUG 3 2013
LONG TRACKED SEVERE THUNDERSTORM CONTINUES TO HOLD TOGETHER AND
MOVE NORTH INTO NORTHERN LARAMIE COUNTY. WENT AHEAD AND ADDED
PLATTE AND GOSHEN COUNTIES TO THE TORNADO WATCH AS THIS STORM
COULD PRODUCE SEVERE THUNDERSTORMS THERE. PLUS THE ENVIRONMENT IS
PROBABLY BETTER UP THERE FOR MORE WIDESPREAD THUNDERSTORM
DEVELOPMENT. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MDT SAT AUG 3 2013
FORECAST CHALLENGES DEAL WITH THUNDERSTORM TIMING AND LOCATION OF
SEVERE THUNDERSTORMS THIS AFTERNOON THROUGH EVENING HOURS.
CURRENTLY...BOUNDARY LAYING ALONG THE LARAMIE RANGE EARLY THIS
AFTERNOON...SEPARATING FAIRLY DRY AIR TO THE WEST FROM REALLY
MOIST AIR TO THE EAST. DEWPOINTS IN LARAMIE IN THE MID 30S...HERE
AT CHEYENNE WE ARE SEEING UPPER 50S AND OUT BY SIDNEY...MID 60
DEWPOINTS. STRATUS HAS BEEN SLOW TO BREAK UP LATE THIS
MORNING/EARLY THIS AFTERNOON. STILL GETTING REPORTS OF STRATUS IN
THE PANHANDLE AND AS FAR WEST AS TORRINGTON. CHEYENNE HAS REMAINED
UNDER MOSTLY SUNNY SKIES AND CUMULUS HAS BEGUN TO BUILD OVER THE
SOUTHERN LARAMIE RANGE...EXTENDING SOUTH INTO THE MOUNTAINS OF
COLORADO. GETTING OBSERVED LIGHTNING STRIKES OVER CENTRAL
COLORADO...BUT SO FAR...THE CHEYENNE CWFA HAS REMAINED PRETTY MUCH
ECHO FREE. MONSOONAL MOISTURE CONTINUES TO MOVE INTO SOUTH CENTRAL
WYOMING ON WATER VAPOR IMAGERY...MAINLY OVER SOUTHERN CARBON AND
ALBANY COUNTIES THROUGH THE MORNING HOURS.
DO BELIEVE ITS ONLY A MATTER OF TIME FOR CONVECTION TO INITIATE
THIS AFTERNOON. LATEST SPC MESOANALIST PAGE SHOWING SURFACE BASED CAPE
VALUES INCREASING TO AROUND 3500 J/KG JUST SOUTH OF THE CWFA IN
COLORADO WITH AROUND 2500 TO 3000 J/KG JUST NUDGING INTO THE SOUTH
LARAMIE RANGE. STILL SEEING SOME CONVECTIVE INHIBITION EAST OF
CHEYENNE...SPREADING NORTH AND EAST. SPC MESOANALYST PAGE SHOWING
STILL AROUND 100-150 J/KG CONVECTIVE INHIBITION FOR THESE AREAS.
CURRENTLY THINKING AND THIS IS BACKED UP BY LATEST HRRR FORECASTS
IS THAT CONVECTION WILL INITIATE JUST WEST OF CHEYENNE...THEN
SLOWLY SPREAD EAST AND NORTH AS THE CAP ERODES.
MAIN THREATS WITH THUNDERSTORMS TODAY LOOKS TO BE LARGE HAIL AND
DAMAGING WINDS. BULK SHEAR ON THE ORDER OF 40 TO 45KTS. BUT LATER
THIS AFTERNOON...NAM SOUNDINGS ARE SHOWING HELICITY VALUES
INCREASING ABOVE 200 M2/S2 FOR CHEYENNE AND THE SOUTHERN
PANHANDLE...SO CAN NOT RULE OUT SOME TORNADIC SUPERCELLS LATE THIS
AFTERNOON AND EARLY EVENING. LCLS PRETTY LOW...WITH NAM FORECASTING
ANYWHERE FROM 2K TO 3K AGL. FINALLY...HEAVY RAIN IS A CONCERN WITH
PWATS CLIMBING TO OVER 1 INCH HERE AT CHEYENNE AND 1.4 INCHES OUT
BY SIDNEY. STORM MOTIONS ARE FAIRLY SLOW...GENERALLY OUT OF THE
WEST AT LESS THAN 10KTS...SO WE COULD BE LOOKING AT A FLASH FLOOD
THREAT AS WELL IN AREAS THAT SEE TRAINING STORMS. STORMS SHOULD
CONTINUE INTO THE MID TO LATE EVENING HOURS...SPREADING INTO THE
PANHANDLE BY 6 PM OR SO TONIGHT.
FOR SUNDAY...MODELS INDICATING A REPEAT OF TODAYS WEATHER WITH
POSSIBLY CONVECTION FURTHER EAST INTO THE PANHANDLE INITIALLY.
SEVERE THUNDERSTORMS LOOK MORE OUT OVER THE PANHANDLE SUNDAY VS
INITIATING HERE IN SOUTHEAST WYOMING.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 320 PM MDT SAT AUG 3 2013
MAIN FORECAST CONCERN THROUGH NEXT WEEK WILL BE A STRONG MID
SUMMER COLD FRONT PUSHING ACROSS THE GREAT PLAINS AND INTO THE
FORECAST AREA...AS THE DEEP 543DM UPPER LEVEL LOW SETTLES OVER
SOUTHERN CANADA NEAR THE GREAT LAKES REGION. THIS IS PRETTY
UNUSUAL FOR THIS TIME OF THE YEAR...ALTHOUGH THE ROCKY MOUNTAIN
REGION WILL NOT SEE THE MAJORITY OF THIS COOLER AIR. MODELS SHOW
THIS FRONT QUICKLY MOVING ACROSS THE AREA TUESDAY AND TUESDAY
EVENING WITH HIGH TEMPERATURES AROUND 10 TO 15 DEGREES COOLER ON
WEDNESDAY AND THURSDAY. WITH SUBTROPICAL MONSOON MOISTURE IN
PLACE...A DAILY CHANCE OF SHOWERS AND THUNDERSTORMS IS ANTICIPATED
ACROSS MOST OF THE FORECAST AREA. THE BEST CHANCE WILL REMAIN OVER
THE MOUNTAINS AND ALONG/EAST OF THE LARAMIE RANGE...PRIMARILY FROM
MID AFTERNOON THROUGH EARLY IN THE EVENING. SOME OF THESE SHOWERS
MAY CONTINUE INTO THE OVERNIGHT HOURS...ESPECIALLY WEDNESDAY AND
THURSDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1024 PM MDT SAT AUG 3 2013
SHOWERS AND THUNDERSTORMS HAVE JUST ABOUT ENDED OVER THE CWA LATE
THIS EVENING. ACTIVITY WILL DEVELOP ONCE AGAIN EARLY SUNDAY
AFTERNOON AND CONTINUE THROUGH THE EVENING. THE STORMS WILL BE
MOST WIDESPREAD OVER THE WESTERN NEBRASKA PANHANDLE. IFR CEILINGS
AND MVFR VISIBILITIES IN FOG CAN BE EXPECTED INTO LATE MORNING
SUNDAY OVER THE WESTERN NEBRASKA PANHANDLE. THOSE CONDITIONS WILL
BE POSSIBLE OVER THE EASTERN PANHANDLE LATE SUNDAY NIGHT AND INTO
MID MORNING MONDAY.
&&
.FIRE WEATHER...
ISSUED AT 300 PM MDT SAT AUG 3 2013
LIGHT WINDS AND MONSOONAL MOISTURE SHOULD KEEP FIRE WEATHER ISSUES
AT BAY FOR TODAY AND SUNDAY. AREAS EAST OF THE LARAMIE RANGE
SHOULD SEE CONTINUED GOOD CHANCES AT WETTING RAINS...HIGH
HUMIDITIES AND EASTERLY UPSLOPING WINDS. AREAS WEST WILL SEE DRIER
CONDITIONS WITH AFTERNOON HUMIDITIES FALLING INTO MID TEENS.
FORTUNATELY...WINDS SHOULD STAY LIGHT OUT THAT WAY KEEPING FIRE
WEATHER CONCERNS MINIMAL. BY MONDAY...SURFACE HIGH PRESSURE MOVING
INTO NORTH CENTRAL COLORADO WILL RE-ESTABLISH WESTERLY WINDS WITH
DRIER AIR FILTERING IN TO AREAS EAST OF THE LARAMIE RANGE. WINDS
WILL REMAIN LIGHT THOUGH...WHICH WILL KEEP FIRE WEATHER MINIMIZED.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...WEILAND
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...WEILAND
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1119 PM MDT MON AUG 5 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 244 PM MDT MON AUG 5 2013
ACTIVE DAY FOR THE WESTERN SLOPES TODAY AS THUNDERSTORMS FIRED UP
EARLIER THAN PAST COUPLE DAYS WITHIN THE MONSOON PLUME. THIS IS OUT
AHEAD OF LEADING DISTURBANCE MOVING THROUGH SOUTHERN AZ.
MEANWHILE...ANOTHER DISTURBANCE IS EXITING EASTERN CO TO THE EAST.
DEW POINTS HAVE BEEN FALLING OFF ACROSS THE SE MTS/I-25 CORRIDOR AS
PROGGED BY MODELS WITH 40 DEW POINTS AND EVEN SOME UPPER 30S. EVEN
OUT TOWARDS LA JUNTA AND LAMAR...DEW POINTS HAVE BEEN FALLING INTO
THE LOWER 50S AS WINDS HAVE SHIFTED OUT OF THE SOUTH AND EVEN
SOUTHWEST AS THE SFC LOW HAS BEEN KICKING EASTWARD.
FOR THE REMAINDER OF THIS EVENING...SCATTERED THUNDERSTORMS EXPECTED
ACROSS THE MOUNTAINS...WITH HRRR SUGGESTING THUNDERSTORMS WILL
SPREAD INTO THE ADJACENT PLAINS DURING THE LATE AFTERNOON/EARLY
EVENING. NOT AS MUCH CAPE TODAY...SO NOT EXPECTING ANY STRONG
STORMS ALONG THE I-25 CORRIDOR. WRF WAS HITTING WALDO BURN SCAR BETWEEN 3-5
PM...WHILE EACH SUCCESSIVE RUN OF THE HRRR HAS BEN DELAYING THIS
POTENTIAL UNTIL A NORTHERLY SURGE AIDED BY CONVECTION ACROSS NE CO
DROPS INTO THE PIKES PEAK REGION JUST AS WEAK FORCING ENHANCING WRN
CO CONVECTION WORKS ITS WAY EASTWARD ACROSS THE SE MTS. THIS PUTS
TIME FRAME FOR WALDO TO GET HIT BETWEEN 6PM-8PM WHICH MAY BE A LITTLE
DELAYED FROM BEST SFC BASED HEATING TO REALIZE STRONG CONVECTION AND
HIGH RAINFALL RATES. BUT THIS WILL HAVE TO BE MONITORED CLOSELY.
OTHER AREA OF CONCERN BESIDES WILL BE OUT WEST ACROSS THE PAPOOSE
AND WEST FORK BURN SCARS WHERE THEY WILL BE UNDER THE GUN FROM
STORMS AND HEAVY RAINFALL/POTENTIAL FLASH FLOODING UNTIL 8 PM.
MEANWHILE...FAR SOUTHEAST PLAINS WILL HAVE TO BE WATCHED CLOSELY AS
CONVECTION ACROSS NW KS SENDS A BOUNDARY SOUTHWESTWARD INTO SE
CO...INCREASING SFC DEW POINTS. COULD SEE SOME THUNDERSTORMS
DEVELOP ALONG THE LEADING EDGE OF THIS OUTFLOW ACROSS
KIOWA...PROWERS AND BACA COUNTIES WITH POTENTIAL FOR A STRONG STORM OR TWO.
MAIN THREAT WINDOW WILL BE DURING THE EVENING...WITH POTENTIAL FOR
NEAR SEVERE HAIL AND WIND. BEST SEVERE THREAT THOUGH APPEARS TO BE
JUST NORTH AND EAST OF THE AREA.
TONIGHT...LOTS OF MID/HIGH CLOUDINESS WILL KEEP TEMPERATURES ON THE
WARM SIDE...WITH POPS DIMINISHING FOR MOST AREAS BY MIDNIGHT. CAN`T
RULE OUT SOME ISOLATED SHOWERS AND THUNDERSTORMS OUT WEST WITHIN THE
MONSOON PLUME. ON TUESDAY...PERHAPS A BIT MORE ACTIVE OUT WEST AS
SHORTWAVES EMBEDDED IN MONSOON PLUME WORK THEIR WAY NORTHWARD
THROUGH AZ INTO SRN UT/FOUR CORNERS REGION TOWARDS 00Z.
CONTEMPLATED GOING WITH A FLASH FLOOD WATCH FOR THE WEST FORK AND
PAPOOSE BURN SCARS TOMORROW...BUT SFC DEW POINTS DON`T APPEAR TO
MOISTEN ALL THAT MUCH...AND MODEL QPFS OFF THE LARGER SCALE MODELS
ARE NOT ALL THAT MUCH HIGHER. STILL THERE IS SOME INCREASE IN
PRECIP WATERS OUT THAT WAY...SO WILL HAVE TO MONITOR THIS
POTENTIAL. WILL LET LATER SHIFTS GET A LOOK AT THE HIGH RES SHORT
RANGE MODELS AS THEY START TO RESOLVE THAT PERIOD. OTHERWISE...FOR
THE EASTERN AREAS LOOKS LIKE MORE OF THE SAME. ANOTHER DAY OF LOWER
SFC DEW POINTS ACROSS THE PLAINS WHICH KEEPS LCLS ON THE HIGH SIDE.
STILL ENOUGH MOISTURE IN THE MONSOON PLUME FOR SOME LOCALLY HEAVY
RAIN WITH THE STRONGER STORMS...BUT FOR NOW THIS THREAT LOOKS TOO
LOCALIZED TO WARRANT ANY FLASH FLOOD WATCHES FOR THE WALDO OR BLACK
FOREST. THIS COULD CHANGE INTO THE EVENING HOURS AS MODELS DROP A
FRONT REINFORCED BY THUNDERSTORM OUTFLOWS INTO THE AREA FROM NE CO.
-KT
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 244 PM MDT MON AUG 5 2013
...HEAVY RAIN EXPECTED ON WEDNESDAY...
HIGH PRESSURE OVER TEXAS AND AN AREA OF LOW PRESSURE OFF THE
NORTHERN CALIFORNIA COAST WILL FORCE SOUTHERLY MONSOON ENERGY
ACROSS COLORADO THROUGH THURSDAY. THIS WILL SET THE STAGE FOR
WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY TUESDAY NIGHT THROUGH
THURSDAY AFTERNOON.
EXPECT ACTIVE SHOWER AND THUNDERSTORM ACTIVITY TUESDAY EVENING
OVER THE MOUNTAINS AND SPREADING INTO THE PLAINS. LOCALLY HEAVY
RAINFALL WILL BE POSSIBLE DURING THIS TIME PERIOD. MODELS
INDICATING A SMALL LULL AROUND MIDNIGHT BEFORE ACTIVITY INCREASES
AGAIN HEADING INTO WEDNESDAY MORNING. HOW QUICKLY THINGS PICK LATE
TUESDAY NIGHT/WEDNESDAY MORNING WILL DEPEND ON HOW FAST A FRONT
MOVES SOUTH ACROSS THE AREA...AND A STRONG SHORTWAVE EJECTS
NORTHEAST OUT OF THE DESERT SOUTHWEST. FRONTAL TIMING LOOKS TO
IMPACT THE AREA BY WEDNESDAY MORNING WITH A VERY MOIST AIR MASS
MOVING INTO THE PLAINS BEHIND THE FRONT. IN ADDITION...LOW LEVEL
FLOW IS FORECAST TO TURN EASTERLY WITH GOOD UPSLOPE FLOW ACROSS
THE PLAINS. ALL OF THESE LOW LEVEL FEATURES WILL COMBINE WITH A
VERY STRONG SHORTWAVE TROUGH ACROSS COLORADO TO PRODUCE WIDESPREAD
MODERATE TO HEAVY RAINFALL ACROSS THE AREA. IN ADDITION...COLDER
AIR ALOFT WILL MOVE INTO THE AREA WHICH WILL LIKELY INCREASE LAPSE
RATES AND INSTABILITY ACROSS COLORADO. THE AREA OF GREATEST
CONCERN WILL BE THE EASTERN MOUNTAINS AND I-25 CORRIDOR. MODELS
ARE INDICATING WELL OVER AN INCH OF PRECIPITATION WILL BE
POSSIBLE...ESPECIALLY IF WE CAN GET ENHANCEMENT FROM CONVECTIVE
UPDRAFTS. THE ONE CAVEAT MAY BE CLOUD COVER ACROSS THE PLAINS
WHICH WOULD LIMIT INSTABILITY AND CONVECTIVE ENHANCEMENT. THIS
WILL NEED TO BE WATCHED. FLASH FLOODING WILL BE OF GREAT
CONCERN...ESPECIALLY FOR AREA BURN SCARS. EXTREME CAUTION IS
ADVISED AND FOLKS SHOULD REMAIN COGNIZANT OF THE WEATHER AROUND
THEM. THE UPPER SYSTEM WILL BE SLOW TO MOVE OUT...WITH THE
MODERATE TO HEAVY RAINFALL SLOWLY MOVING EAST ACROSS THE PLAINS
WEDNESDAY NIGHT.
THURSDAY...MOISTURE WILL BE IN PLACE AND DEPARTING UPPER LEVEL
ENERGY WILL LIKELY LEAD TO SHOWERS AND THUNDERSTORMS DEVELOPING
OVER THE MOUNTAINS THURSDAY AFTERNOON. LOCALLY HEAVY RAINFALL WILL
BE POSSIBLE...AND FLASH FLOODING WILL BE POSSIBLE OVER AREA BURN
SCARS. IF TRENDS HAVE ANYTHING TO SAY ABOUT IT...THE DAY AFTER
EXPECTED WIDESPREAD HEAVY RAINFALL EVENTS SEEM TO BE PRIMED FOR
HEAVIER RAINFALL OUT OF THUNDERSTORMS THAN MODELS SEEM TO
INDICATE.
THE PATTERN BEGINS TO SHIFT FRIDAY INTO EARLY NEXT WEEK. THE LOW
OFF NORTHERN CALIFORNIA WILL DRIFT NORTHWARD HAS HIGH PRESSURE
OVER TEXAS BUILDS NORTH ACROSS COLORADO. THE MAIN MONSOONAL TAP
SHIFTS WESTWARD INTO THE GREAT BASIN. MODELS ARE INDICATING A
DOWNWARD TREND IN CONVECTIVE ACTIVITY THROUGH THE WEEKEND WITH
SHOWER AND THUNDERSTORM ACTIVITY REMAINING CONFINED TO MOUNTAIN
AREAS. MOZLEY
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1117 PM MDT MON AUG 5 2013
VFR CONDITIONS ARE EXPECTED OVER THE KALS...KCOS AND KPUB TAF
SITES FROM TONIGHT INTO TUESDAY AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
134 AM EDT TUE AUG 6 2013
.AVIATION...
RIDGING CONTINUES TO CONTROL THE PATTERN THROUGH THIS TAF PERIOD.
A HIGH PRESSURE RIDGE OVER MOST OF THE GULF OF MEXICO HAS TURNED
TO MID LEVEL FLOW MORE NORTHERLY TONIGHT. THIS WILL KEEP UPPER
LEVEL CLOUD COVER OVER SOUTH FLORIDA FOR A GOOD PART OF THE OVER
NIGHT HOURS. TOMORROW, THE SEA BREEZE WILL DEVELOP AS CLOUDS
BECOME MORE SCT IN NATURE AND ALLOW DAYTIME HEATING. THIS WILL
ALLOW SHOWERS AND THUNDERSTORMS TO DEVELOP ONCE AGAIN, MAINLY IN
THE INTERIOR OF SOUTH FLORIDA. BY VERY EARLY AFTERNOON,
THUNDERSTORMS COULD BEGIN TO INFRINGE ON THE TAF SITES. HAVE TAKE
VCTS OUT FOR THE MORNING HOURS, AS CHANCES ARE LOWER THAN 30
PERCENT, BUT KEPT THEM IN AFTER 17Z AT ALL ATLANTIC SITES. KAPF
MAY SEE A SLIGHTLY EARLIER START. WINDS TOMORROW WILL TRY TO
PICKUP OUT OF THE NNW, BUT SHOULD BECOME INFLUENCED BY THE SEA
BREEZE AFTER 17Z. VFR CONDITIONS, OTHER THEN AREAS UNDER
CONVECTION, WILL BE THE GENERAL RULE THROUGH THE TAF PERIOD.
&&
.PREV DISCUSSION... /ISSUED 815 PM EDT MON AUG 5 2013/
UPDATE...
CONVECTIVE ACTIVITY CONTINUES TO WANE ACROSS THE NORTHWEST
INTERIOR THIS EVENING...DEVOLVING INTO MAINLY MODERATE STRATIFORM
RAIN SHOWERS. LATEST HRRR CONTINUES TO SHOW THE REMAINDER OF THE
LINGERING RAINFALL TO DISSIPATE OVER THE NEXT FEW HOURS AS IT
SLOWLY HEADS TO THE SOUTH. INCREASED POPS THROUGH THE EVENING TO
ACCOUNT FOR THE RATHER LARGE STRATIFORM RAIN SHIELD. THE REMAINDER
OF THE FORECAST LOOKS GOOD AT THIS TIME.
PREV DISCUSSION... /ISSUED 208 PM EDT MON AUG 5 2013/
SHORT TERM (TONIGHT-TUESDAY NIGHT)...
CURRENT SYNOPTIC ANALYSIS SHOWS STRONG MID LEVEL RIDGE CENTERED OVER
TEXAS WITH ITS RIDGE AXIS STRETCHING TO THE SOUTHEAST ACROSS THE
STRAITS OF FLORIDA. AT THE SURFACE, A TROUGH EXTENDS ACROSS NORTH
CENTRAL FLORIDA INTO THE ATLANTIC WITH A SURFACE RIDGE OVER THE
FLORIDA KEYS. THIS IS CONTINUING THE WESTERLY STEERING FLOW FOR SOUTH
FLORIDA WITH THE BEST CHANCES FOR THUNDERSTORMS OVER THE INTERIOR
AND EAST COAST METRO REGION THROUGH EARLY THIS EVENING. THE
OVERNIGHT HOURS TONIGHT WILL BE MOSTLY TRANQUIL ONCE THE DIURNAL
HEATING CYCLE IS LOST AND THE LOW LEVEL FLOW BECOMES LIGHT AND
VARIABLE.
ON TUESDAY, SOUTH FLORIDA WILL UNDERGO A TRANSITIONAL PERIOD AS A
MID LEVEL INVERTED TROUGH APPROACHES FROM THE EAST. THIS TROUGH IS
CURRENTLY NEAR HISPANIOLA AND HAS BEEN WELL TRACKED BY THE GLOBAL
MODELS. IT WILL MOVE INTO THE EASTERN BAHAMAS ON TUESDAY WHICH WILL
GRADUALLY SHIFT THE MID/UPPER WIND FLOW TO A NORTHEAST DIRECTION. AT
THE SAME TIME, A SURFACE RIDGE WILL BUILD FROM THE CENTRAL GULF OF
MEXICO TO THE SOUTHEAST U.S. VEERING THE LOW LEVEL WIND TO AN EAST
DIRECTION ACROSS OUR REGION. THE FORECAST SOUNDINGS ARE INDICATING
PWAT REMAINING NEAR TWO INCHES SO STORMS WILL TEND TO DEVELOP NEAR
THE EAST COAST AND THEN SLOWLY DRIFT TOWARDS THE WEST INTO THE
EVERGLADES AND SOUTHWEST COAST. THE INVERTED TROUGH WILL MOVE INTO
THE CENTRAL BAHAMAS ON WEDNESDAY WITH A SURFACE RIDGE ACROSS NORTH
FLORIDA. THIS WILL RESULT IN A DEEP EASTERLY FLOW BECOMING
ESTABLISHED ACROSS SOUTH FLORIDA. THIS COULD BRING AN INCREASING
CHANCE OF NOCTURNAL SHOWERS ALONG THE EAST COAST TUESDAY NIGHT INTO
WEDNESDAY MORNING AND A THREAT FOR AFTERNOON THUNDERSTORMS ACROSS
THE INTERIOR AND SOUTHWEST COAST. AT THIS TIME, THE ATMOSPHERIC
INSTABILITY PROFILE DOES NOT CHANGE MUCH WITH PWAT CONTINUING AROUND
TWO INCHES AND WEAK MID LEVEL LAPSE RATES.
LONG TERM (WEDNESDAY-MONDAY)...
LOOKING AHEAD INTO THE EXTENDED PERIOD, THURSDAY APPEARS TO BE
SOMEWHAT UNCERTAIN AS TO THE CHANCE FOR THUNDER. THE INVERTED TROUGH
WILL MOVE ACROSS THE AREA WITH A STRONG DEEP LAYER RIDGE OVER NORTH
FLORIDA. THIS TRANSLATES TO EASTERLY FLOW THROUGH THE ENTIRE
ATMOSPHERE ACROSS SOUTH FLORIDA. IN FACT, THE LATEST 12Z RUN OF THE
GFS IS INDICATING A STEERING FLOW OF 15 TO 20 MPH BY THURSDAY
AFTERNOON AND IF THIS VERIFIES THE CHANCE FOR THUNDER WOULD BE
MINIMAL WITH A MAJORITY OF THE ACTION BEING FAST MOVING SHOWERS.
HOWEVER, THE TROUGH IN PLACE WILL ALSO DESTABILIZE THE MID LEVELS
WITH MODELS ALSO SHOWING SIGNIFICANT COOLING ALOFT. FOR THIS REASON,
DO NOT PLAN TO CHANGE FROM THE CURRENT FORECAST AND WILL WAIT FOR
FUTURE GUIDANCE BEFORE MAKING A DECISION. THE TROUGH WILL CONTINUE
MOVING WEST INTO THE GULF OF MEXICO ON FRIDAY AND INTO THE WEEKEND
WITH THE ATLANTIC RIDGE BUILDING WEST ACROSS THE PENINSULA. THE GFS
IS ALSO SHOWING SIGNIFICANT DRYING ALOFT WITH DEEP EASTERLY FLOW
CONTINUING SO THIS WILL SET THE STAGE FOR SCATTERED SHOWERS/ISOLATED
THUNDER MOSTLY OVER THE INTERIOR AND SOUTHWEST COAST.
MARINE...
THE SOUTHWEST TO WEST WIND WILL GRADUALLY SHIFT TO THE NORTHEAST
AND EAST ON TUESDAY THEN BECOMING EAST ON WEDNESDAY WHILE
INCREASING SPEED TO POSSIBLY 15 KNOTS OVER THE ATLANTIC. THIS WILL
RESULT IN BUILDING SEAS BY MIDWEEK BUT REMAINING BELOW ADVISORY
LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 91 77 90 78 / 50 20 30 20
FORT LAUDERDALE 89 80 89 79 / 50 20 30 30
MIAMI 91 78 89 80 / 50 20 30 30
NAPLES 92 76 92 76 / 40 20 40 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
137 AM EDT TUE AUG 6 2013
.PREV DISCUSSION... /ISSUED 1041 PM EDT MON AUG 5 2013/
UPDATE...
NO MAJOR CHANGES TO THE FORECAST THIS EVENING. WILL NEED TO WATCH
TRENDS OVERNIGHT PER LATEST HRRR RUNS WHICH FIRE UP SOME STORMS
OVER CENTRAL GA AROUND 07Z. HARD TO FIND ANY EVIDENCE IN OTHER
SHORT TERM MODELS...BUT WORTH WATCHING NONETHELESS AS THE REMNANT
SEA BREEZE BOUNDARY WORKS INTO THAT REGION. OF MORE INTEREST IS
THE CONVECTION NOTED IN NE GA AFTER 07Z IN BOTH THE HRRR AND RUC.
WILL AGAIN NEED TO WATCH TRENDS AS ONLY THE LATEST RUNS HAVE BEEN
INDICATING THIS.
PREV DISCUSSION... /ISSUED 827 PM EDT MON AUG 5 2013/
PREV DISCUSSION... /ISSUED 348 PM EDT MON AUG 5 2013/
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
MODELS CONSISTENT THROUGH THE SHORT TERM WITH LARGE UPPER LEVEL
RIDGE OVER THE SOUTH-CENTRAL U.S. AND LONG-WAVE TROUGH PUSHING EAST
OF THE ATLANTIC COAST. MORE OF A ZONAL FLOW ANTICIPATED ACROSS THE
REGION AS A RESULT...BUT NOT BEFORE SHORTWAVE DROPS INTO THE AREA
TONIGHT AND INTO TUESDAY.
ALREADY SEEING SOME VERY ISOLATED SHOWER DEVELOPMENT THIS
AFTERNOON...MAINLY ALONG THE SOUTHEASTERN EDGE OF THE CWA WITH THE
INFLUENCE OF THE STALLED WEAK SURFACE BOUNDARY. EXPECT THE LOCATION
OF ACTIVITY TO TRANSITION TO THE NORTH AS SHORTWAVE APPROACHES. HAVE
CONTINUED WITH SLIGHT CHANCE TO CHANCE POPS EVERYWHERE THROUGH THE
AFTERNOON...WITH ONLY SLIGHT CHANCE POPS ACROSS THE NORTH AFTER
03-04Z. POPS INCREASE INTO TUESDAY MORNING AND CONTINUE WITH GOOD
CHANCE POPS THROUGH TUESDAY AS SHORTWAVE...COMBINED WITH GOOD
MOISTURE ACROSS THE AREA...RESULTS IN BETTER COVERAGE OF SHOWERS AND
THUNDERSTORMS.
AS FOR TEMPERATURES...HAVE GONE WITH A BLEND OF THE MODEL
GUIDANCE...WHICH HAS WORKED WELL THE LAST SEVERAL DAYS. TUESDAY
HIGHS WILL BE CLOSELY TIED TO PRECIP AND CLOUD COVER...SO ALTHOUGH
FORECAST IS SHOWING MID 80S TO NEAR 90...COULD SEE A FEW DEGREE
ADJUSTMENT BASED ON FUTURE MODEL RUN GUIDANCE.
31
LONG TERM /WEDNESDAY THROUGH MONDAY/...
NO MAJOR CHANGES WERE MADE TO THE EXTENDED PERIOD. LONG RANGE
MODELS CONTINUE TO SHOW A DEEP SOUTHERLY WIND FLOW BECOMING
ESTABLISHED ON WEDNESDAY AND AN OLD FRONTAL BOUNDARY BECOMING
DIFFUSE. THE INCREASING MOISTURE AND INSTABILITY WILL RESULT IN A
MORE SCATTERED TO NUMEROUS COVERAGE OF MAINLY DIURNALLY DRIVEN
CONVECTION THROUGH FRIDAY. MODELS SHOW A FRONTAL BOUNDARY APPROACHING
NORTH GA ON SATURDAY... PUSHING INTO NORTH GA ON SUNDAY... AND
BECOMING NEARLY STATIONARY ACROSS CENTRAL GA ON MONDAY. THIS WOULD
WARRANT SLIGHTLY HIGHER POPS ACROSS AT LEAST NORTH GA ON SATURDAY
AND SUNDAY... THEN ACROSS CENTRAL GA BY MONDAY... AS A DRIER... MORE
STABLE AIR MASS BEGINS TO SPREAD INTO NORTH GA ON MONDAY BEHIND
THE FRONT. ALTHOUGH WIDESPREAD ORGANIZED SEVERE STORMS ARE NOT
EXPECTED WITH THIS OVERALL SYNOPTIC WEATHER PATTERN... AN ISOLATED
PULSE STRONG TO SEVERE STORM CANNOT BE RULED OUT EACH DAY...
ESPECIALLY DURING MAX DAYTIME HEATING.
&&
.AVIATION...
06Z UPDATE...
MVFR CIGS ALREADY MOVING IN TOWARD AHN...AND THIS SHOULD SPREAD
WEST OVER THE NEXT COUPLE OF HOURS. MAY SEE BRIEF IFR...BUT
CONFIDENCE NOT HIGH. CSG MAY REMAIN VFR BUT CURRENT TAF DOES HAVE
THEM GOING MVFR TOWARD SUNRISE. WINDS STILL SORT OF ALL OVER THE
PLACE...LGT/VRB. EXPECT A MAINLY SE COMPONENT THOUGH SWITCHING TO
SW AROUND 15Z...BACK TO SOLIDLY SE AFTER 00Z. HAVE CONTINUED
PROB30 FOR AFTN TSRA BUT WILL REEVALUATE FOR 08Z AMD. INTRODUCED
MVFR CIGS AT 06Z TUESDAY AS WELL.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM-HIGH ON CIGS.
MEDIUM ON WINDS.
MEDIUM-HIGH ON CONVECTION.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 84 71 86 71 / 40 30 50 40
ATLANTA 86 72 86 72 / 40 30 50 30
BLAIRSVILLE 83 69 80 67 / 40 40 60 50
CARTERSVILLE 87 72 87 72 / 30 30 50 40
COLUMBUS 92 74 90 74 / 30 20 40 20
GAINESVILLE 83 71 83 71 / 40 30 50 40
MACON 88 71 88 72 / 40 20 40 20
ROME 89 72 88 72 / 30 30 50 40
PEACHTREE CITY 87 71 87 72 / 40 20 50 20
VIDALIA 88 72 91 73 / 40 20 40 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ATWELL
LONG TERM....ATWELL
AVIATION...TDP
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
421 AM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURFACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTION ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCED
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVECTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPAGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE SCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
WHILE THE CONVECTION IS LIKELY TO BE ON A WEAKENING TREND INTO
WEDNESDAY MORNING...IF NOT ALREADY OVERNIGHT...GUIDANCE HAS AGREED
ON A SLOWER MOVEMENT OF THE FRONT IN THE PAST 24 HOURS. SO HAVE
INCREASED POPS IN EASTERN AREAS DURING EARLY WEDNESDAY.
CONFIDENCE...MEDIUM.
WEDNESDAY AFTERNOON THROUGH FRIDAY...AS THE FRONT EASES IN SPEED
THERE IS CONCERN FOR CONVECTION IN THE SOUTHEAST PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON. HIGH MOISTURE WILL STILL OWE TO
MODEST TO HIGH INSTABILITY ALONG THE BOUNDARY. EVEN A SLOWER
FRONTAL MOVEMENT MAY MEAN WE COULD HAVE A SEVERE WEATHER THREAT IN
THE FAR SOUTHERN FORECAST AREA. FOR THE TIME BEING MAINTAIN THE
CHANCE POPS IN THE SOUTHERN AREA.
LARGER INCREASES IN POPS WERE MADE FOR THU NIGHT AND INTO FRI
ACROSS THE SOUTHEAST HALF OF THE FORECAST AS ONE AND POSSIBLY
MULTIPLE WAVES TRAVERSE THE BOUNDARY...SPREADING SOUTHERLY 850MB
FLOW NORTH OF THE FEATURE POTENTIALLY LEADING TO SOME SHOWERS AND
STORMS ACROSS OUR AREA...DESPITE NORTHERLY SURFACE FLOW. THE MAIN
FOCUS FOR ANYTHING OF HIGH IMPACT STILL LOOKS TO BE WELL SOUTH OF
THE AREA. FOR TEMPERATURES ON WED-FRI HAVE GONE JUST A COUPLE
DEGREES ABOVE AN OFFICIAL/MODEL BLEND.
THIS WEEKEND...LITTLE CHANGES MADE TO THE GOING FORECAST AS HIGH
PRESSURE IS STILL FAVORED IN THAT TIME YIELDING LIKELY PLEASANT
WEATHER. GUIDANCE MAY BE A LITTLE QUICK ON BRINGING PRECIP
CHANCES BACK SUNDAY NIGHT...BUT FOR THE TIME BEING HAVE GONE WITH
A BLEND DUE TO ATTENTION ON THE SHORT TERM.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* ISOLATED SHOWERS/ VCTS EARLY THIS MORNING.
* CIG TRENDS WITH LOW MVFR CIGS DOWN AROUND 1500 FEET EARLY THIS
MORNING.
* TIMING THE IMPROVEMENT OF THESE LOWER CIGS DURING THE MID TO
LATE MORNING HOURS.
* GOOD CHANCE OF TSRA TUESDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE PRIMARY FORECAST CONCERNS IN THE NEAR TERM WILL BE CIGS AND
VIS...ESPECIALLY THROUGH MID MORNING. ATTENTION THEN TURNS TO LATER
TONIGHT INTO WEDNESDAY MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A RATHER
COMPLICATED CIG AND VIS FORECAST OVERNIGHT...AS AREAS WHERE THE
CLOUDS ARE DISSIPATING LOWER CLOUDS AND FOG ARE DEVELOPING. CURRENT
THINKING IS THAT IT MAY TAKE A FEW MORE HOURS TO GET CIGS TO DROP
BELOW 2000 FT AGL AT THE EASTERN TAF SITES...AND WITH MORE CLOUD
COVER THE THREAT FOR FOG APPEARS LOW...ESPECIALLY AT ORD AND MDW.
THE FOG THREAT IS A BIT UNCERTAIN AT DPA AND RFD AS LOW CIGS MAY BE
THE RULE. HOWEVER...WITH VERY LOW DEW POINT DEPRESSIONS...IT WILL
NOT TAKE MUCH TO GET THE VIS TO TANK. WITH THIS IN MIND...I DECIDED
TO
LEAVE THE TEMPO GROUPS FOR A PERIOD OF LOW VIS IN THE NEW TAF
FORECAST AT RFD AND DPA.
THERE HAVE AS BEEN A CONTINUED REDEVELOPMENT OF MAINLY SHOWERS
ACROSS FAR NORTHERN ILLINOIS AS THE FLOW ALOFT REMAINS RATHER
UNSETTLED. THIS WILL LIKELY CONTINUE TO BE THE CASE FOR THE NEXT FEW
HOURS ACROSS THE AREA. I EXTENDED THE VCSH TO ACCOUNT FOR THESE
SHOWERS. OVERALL THE THREAT FOR THUNDER WILL BE
LOW...HOWEVER...THERE HAVE BEEN A FEW STRIKES IN THE CELL ACROSS
STEPHENSON COUNTY. THIS CELL COULD APPROACH KRFD AFTER 07 UTC.
CIGS LOOK TO BE SLOW TO INCREASE THIS MORNING...BUT ONCE THEY
DO...THINGS SHOULD BE QUIET UNTIL TONIGHT. IT APPEARS LIKELY THAT A
COMPLEX OF THUNDERSTORMS WILL DEVELOP WEST OF THE AREA ACROSS IOWA
AND SOUTHWESTERN WISCONSIN DURING THE EVENING TODAY. THIS ACTIVITY
APPEARS THAT IT WILL MOVE OVER NORTHERN ILLINOIS LATER
TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY AT THE EASTERN TAF SITS.
I DID ADD A MENTION OF SHRA AND VCTS TO THE ORD 30 HR TAF AFTER 08
UTC. IT IS POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW
HOURS PRIOR TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE
TONIGHT INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE
APPROACHES THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN
THE AIRMASS AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN A BRIEF PERIOD OF SHOWERS THIS MORNING...WITH
VCTS.
* MEDIUM CONFIDENCE IN MVFR CIG/VIS CONDITIONS DEVELOPING FOR A
PERIOD THIS MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TUESDAY
NIGHT...WITH ONLY LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...CHANCE TSRA MAINLY MORNING. OTHERWISE VFR.
THURSDAY THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY SOUTH OF
CHICAGO THURSDAY NIGHT.
RATZER
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
420 AM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURFACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTION ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCD
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVECTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPAGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE DCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
CONFIDENCE...MEDIUM.
THE REST OF THE DISCUSSION WILL BE SENT SHORTLY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* ISOLATED SHOWERS/ VCTS EARLY THIS MORNING.
* CIG TRENDS WITH LOW MVFR CIGS DOWN AROUND 1500 FEET EARLY THIS MORNING.
* TIMING THE IMPROVEMENT OF THESE LOWER CIGS DURING THE MID TO
LATE MORNING HOURS.
* GOOD CHANCE OF TSRA TUESDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE PRIMARY FORECAST CONCERNS IN THE NEAR TERM WILL BE CIGS AND
VIS...ESPECIALLY THROUGH MID MORNING. ATTENTION THEN TURNS TO LATER
TONIGHT INTO WEDNESDAY MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A RATHER
COMPLICATED CIG AND VIS FORECAST OVERNIGHT...AS AREAS WHERE THE
CLOUDS ARE DISSIPATING LOWER CLOUDS AND FOG ARE DEVELOPING. CURRENT
THINKING IS THAT IT MAY TAKE A FEW MORE HOURS TO GET CIGS TO DROP
BELOW 2000 FT AGL AT THE EASTERN TAF SITES...AND WITH MORE CLOUD
COVER THE THREAT FOR FOG APPEARS LOW...ESPECIALLY AT ORD AND MDW.
THE FOG THREAT IS A BIT UNCERTAIN AT DPA AND RFD AS LOW CIGS MAY BE
THE RULE. HOWEVER...WITH VERY LOW DEW POINT DEPRESSIONS...IT WILL
NOT TAKE MUCH TO GET THE VIS TO TANK. WITH THIS IN MIND...I DECIDED TO
LEAVE THE TEMPO GROUPS FOR A PERIOD OF LOW VIS IN THE NEW TAF
FORECAST AT RFD AND DPA.
THERE HAVE AS BEEN A CONTINUED REDEVELOPMENT OF MAINLY SHOWERS
ACROSS FAR NORTHERN ILLINOIS AS THE FLOW ALOFT REMAINS RATHER
UNSETTLED. THIS WILL LIKELY CONTINUE TO BE THE CASE FOR THE NEXT FEW
HOURS ACROSS THE AREA. I EXTENDED THE VCSH TO ACCOUNT FOR THESE
SHOWERS. OVERALL THE THREAT FOR THUNDER WILL BE
LOW...HOWEVER...THERE HAVE BEEN A FEW STRIKES IN THE CELL ACROSS
STEPHENSON COUNTY. THIS CELL COULD APPROACH KRFD AFTER 07 UTC.
CIGS LOOK TO BE SLOW TO INCREASE THIS MORNING...BUT ONCE THEY
DO...THINGS SHOULD BE QUIET UNTIL TONIGHT. IT APPEARS LIKELY THAT A
COMPLEX OF THUNDERSTORMS WILL DEVELOP WEST OF THE AREA ACROSS IOWA
AND SOUTHWESTERN WISCONSIN DURING THE EVENING TODAY. THIS ACTIVITY
APPEARS THAT IT WILL MOVE OVER NORTHERN ILLINOIS LATER
TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY AT THE EASTERN TAF SITS.
I DID ADD A MENTION OF SHRA AND VCTS TO THE ORD 30 HR TAF AFTER 08
UTC. IT IS POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW
HOURS PRIOR TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE
TONIGHT INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE
APPROACHES THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN
THE AIRMASS AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN A BRIEF PERIOD OF SHOWERS THIS MORNING...WITH
VCTS.
* MEDIUM CONFIDENCE IN MVFR CIG/VIS CONDITIONS DEVELOPING FOR A
PERIOD THIS MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TUESDAY
NIGHT...WITH ONLY LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...CHANCE TSRA MAINLY MORNING. OTHERWISE VFR.
THURSDAY THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY SOUTH OF
CHICAGO THURSDAY NIGHT.
RATZER
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
343 AM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTINO ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBIILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCD
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVCTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPOGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE DCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
CONFIDENCE...MEDIUM.
THE REST OF THE DISCUSSION WILL BE SENT SHORTLY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* ISOLATED SHOWERS EARLY THIS MORNING.
* CIG TRENDS WITH MVFR CIGS DOWN AROUND 1500 FEET BY DAYBREAK.
* TIMING THE IMPROVEMENT OF THESE LOWER CIGS DURING THE MORNING.
* GOOD CHANCE OF TSRA TUESDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE PRIMARY FORECAST CONCERNS IN THE NEAR TERM WILL BE CIGS AND
VIS...ESPECIALLY THROUGH MID MORNING. ATTENTION THEN TURNS TO LATER
TONIGHT INTO WEDNESDAY MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A RATHER
COMPLICATED CIG AND VIS FORECAST OVERNIGHT...AS AREAS WHERE THE
CLOUDS ARE DISSIPATING LOWER CLOUDS AND FOG ARE DEVELOPING. CURRENT
THINKING IS THAT IT MAY TAKE A FEW MORE HOURS TO GET CIGS TO DROP
BELOW 2000 FT AGL AT THE EASTERN TAF SITES...AND WITH MORE CLOUD
COVER THE THREAT FOR FOG APPEARS LOW...ESPECIALLY AT ORD AND MDW.
THE FOG THREAT IS A BIT UNCERTAIN AT DPA AND RFD AS LOW CIGS MAY BE
THE RULE. HOWEVER...WITH VERY LOW DEW POINT DEPRESSIONS...IT WILL
NOT TAKE MUCH TO GET THE VIS TO TANK. WITH THIS IN MIND...I DECIDED TO
LEAVE THE TEMPO GROUPS FOR A PERIOD OF LOW VIS IN THE NEW TAF
FORECAST AT RFD AND DPA.
THERE HAVE AS BEEN A CONTINUED REDEVELOPMENT OF MAINLY SHOWERS
ACROSS FAR NORTHERN ILLINOIS AS THE FLOW ALOFT REMAINS RATHER
UNSETTLED. THIS WILL LIKELY CONTINUE TO BE THE CASE FOR THE NEXT FEW
HOURS ACROSS THE AREA. I EXTENDED THE VCSH TO ACCOUNT FOR THESE
SHOWERS. OVERALL THE THREAT FOR THUNDER WILL BE
LOW...HOWEVER...THERE HAVE BEEN A FEW STRIKES IN THE CELL ACROSS
STEPHENSON COUNTY. THIS CELL COULD APPROACH KRFD AFTER 07 UTC.
CIGS LOOK TO BE SLOW TO INCREASE THIS MORNING...BUT ONCE THEY
DO...THINGS SHOULD BE QUIET UNTIL TONIGHT. IT APPEARS LIKELY THAT A
COMPLEX OF THUNDERSTORMS WILL DEVELOP WEST OF THE AREA ACROSS IOWA
AND SOUTHWESTERN WISCONSIN DURING THE EVENING TODAY. THIS ACTIVITY
APPEARS THAT IT WILL MOVE OVER NORTHERN ILLINOIS LATER
TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY AT THE EASTERN TAF SITS.
I DID ADD A MENTION OF SHRA AND VCTS TO THE ORD 30 HR TAF AFTER 08
UTC. IT IS POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW
HOURS PRIOR TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE
TONIGHT INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE
APPROACHES THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN
THE AIRMASS AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN MVFR CIG/VIS CONDITIONS DEVELOPING
OVERNIGHT AND LINGERING THROUGH MID MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TUESDAY
NIGHT...WITH ONLY LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...CHANCE TSRA MAINLY MORNING. OTHERWISE VFR.
THURSDAY THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY SOUTH OF
CHICAGO THURSDAY NIGHT.
RATZER
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
259 AM CDT TUE AUG 6 2013
.DISCUSSION...
755 PM CDT
EVENING UPDATE:
MADE TWEAKS TO EVENING GRIDS TO BACK OFF TO ISOLATED SHRA MENTION
FOR APPROXIMATELY NORTHEASTERN HALF OF CWA. SHEARED OUT WAVE AND
MID LEVEL SPEED MAX CONTINUES TO PUSH ACROSS REGION WITH
SIGNIFICANT DRYING NOTED ON WATER VAPOR IN WAKE OF THIS WAVE.
LATEST RAP MESOANALYSIS HAS SHOWN IN INCREASE IN ELEVATED CAPE BUT
00Z DVN RAOB INDICATES THAT THIS IS LIKELY OVERDONE WITH VERY
MARGINAL INSTABILITY AND WEAK MID LEVEL LAPSE RATES ON THE
SOUNDING. WITH THE FORCING FROM THE MIDLEVEL WAVE
OVERHEAD...RETURNS OVER SOUTHWEST WISCONSIN HAVE INCREASED A BIT
IN RECENT SCANS BUT GIVEN THAT INSTABILITY FURTHER DIMINISHES INTO
OUR CWA...THIS ACTIVITY WILL LIKELY ONLY SURVIVE INTO CWA AS
SPOTTY PRIMARILY LIGHT SHOWERS. AN OUTSIDE CHANCE EXISTS FOR AN
ISOLATED T-STORM. THEN WENT WITH A DRY FORECAST AFTER MIDNIGHT FOR
ENTIRE AREA AS FORCING FROM VORT MAX WILL TRANSLATE EAST OF US BY
ABOUT MIDNIGHT.
ATTENTION WILL THEN TURN TO FOG POTENTIAL OVERNIGHT AS AIR MASS
REMAINS MOIST AND WINDS WILL CONTINUE TO DIMINISH. UNCERTAINTY AS
TO WHETHER STRATUS OR FOG IS THE PRIMARY MODE BUT IF BETTER CLEARING
CAN OCCUR...FOG WOULD BECOME MORE FAVORABLE AND EVEN POTENTIALLY
BECOME LOCALLY DENSE. OBS OVER SW WISCONSIN SHOW VSBY BETWEEN 2
AND 4 MILES AND LATEST GUIDANCE STILL SUPPORTS BEST CHANCE FOR
MORE WIDESPREAD FOG TO DEVELOP WELL WEST OF THE LAKEFRONT SO WILL
CONTINUE TO MONITOR OBSERVATIONAL TRENDS THIS EVENING AND MAKE
FURTHER UPDATES IF NEEDED. UPDATED ZONE PRODUCT HAS BEEN SENT.
RC
//PREV DISCUSSION...
312 PM CDT
A PREDOMINANTLY NORTHWESTERLY UPPER FLOW PATTERN WILL BE IN PLACE
THROUGH THE PERIOD WITH OCCASIONAL BUCKLING TO A MORE WESTERLY
DIRECTION OVER THE NEXT FEW DAYS. AS A RESULT...TIMING MODEST PRECIP
CHANCES WILL BE THE MAIN CHALLENGE THROUGH LATE WEEK. WATER VAPOR
IMAGERY SHOWS AN UPPER LOW CENTERED OVER SOUTHWESTERN PORTIONS OF
HUDSON BAY WHILE A LARGE UPPER ANTICYCLONE SPINS OVER TEXAS. BETWEEN
THE TWO...IS A BELT OF NORTHWESTERLY UPPER FLOW STRETCHED FROM THE
NORTHERN U.S. ROCKIES TO THE SOUTHEAST COAST. A CLOSER LOOK AT
SATELLITE SHOWS SEVERAL EMBEDDED SHORTWAVES WITHIN THIS FLOW...WITH
ONE HAVING PASSED OVER THE AREA EARLIER TODAY WITH ANOTHER
APPROACHING LATE THIS AFTERNOON. A LARGER SCALE TROUGH AXIS EXTENDS
FROM THE HUDSON BAY LOW WEST-SOUTHWEST WHERE A SMALLER SCALE
CIRCULATION IS NOTED OVER SOUTHERN ALBERTA. THIS WILL BE KEY IN OUR
WEATHER TUESDAY NIGHT AND WEDNESDAY. FURTHER WEST...ANOTHER UPPER
LOW IS CUTOFF OFF THE NORTHERN CALIFORNIA COAST AND MOVING VERY
LITTLE AS A RESULT. AT THE SURFACE...HIGH PRESSURE IS CENTERED OVER
EASTERN OHIO AND WESTERN PENNSYLVANIA WHILE A LOW IS CENTERED OVER
NORTHERN ONTARIO. A TROUGH AXIS EXTENDS SOUTHWARD FROM THE LOW INTO
EASTERN MINNESOTA AND IOWA.
THIS EVENING THROUGH TUESDAY...A WEAK SHORTWAVE CONTINUES TO CROSS
THE LOCAL AREA WITH A SMALL CLUSTER OF SHRA/TSRA WORKING
EAST-SOUTHEAST ACROSS THE FAR NORTHWEST ILLINOIS BORDER. THIS LOOKS
TO MAINTAIN ITSELF OVER THE NEXT FEW HOURS BUT LITTLE IF ANY LOW
LEVEL INSTABILITY HAS DEVELOPED THANKS TO AN EXTENSIVE...BUT
THINNING...CLOUD SHIELD. WHAT HAS DEVELOPED THOUGH SUGGESTS THAT
THIS CLUSTER WILL WORK SOUTHEAST TOWARD ROCKFORD...ROCHELLE...AND ON
INTO THE WESTERN/SOUTHWESTERN CHICAGO METRO IF IT MAINTAINS. IN
ADDITION...SOME SPOTTY ACTIVITY MAY DEVELOP AROUND THIS CLUSTER
INTO THE EVENING. A FEW STRONGER CORES HAVE POPPED UP FROM TIME TO
TIME IN THE LAST FEW RADAR SCANS WITH THE ACTIVITY BUT WITH SUCH
LIMITED INSTABILITY...THOUGH THERE IS STRONG SHEAR...MORE THAN AN
ISOLATED HAIL CORE OR WIND GUST LOOKS UNLIKELY. CHANCES WILL
DIMINISH THROUGH THE EVENING. THE AFOREMENTIONED TROUGH AXIS/COOL
FRONT MOVING ACROSS MINNESOTA WILL CONTINUE EASTWARD BUT FALL APART
WITH TIME OVERNIGHT. MID LEVEL DRYING IS EXPECTED OVERNIGHT AND WITH
NO COHERENT SOURCE OF FORCING DO NOT SEE MUCH CHANCE FOR PRECIP BY
LATE TONIGHT...IF NOT BEFORE THAT. THE AREA WILL BE BETWEEN SYSTEMS
TUESDAY WHICH SHOULD LEAD TO DRY CONDITIONS THROUGH AT LEAST THE
FIRST PART OF THE DAY BEFORE SMALL CHANCES INCREASE LATER IN THE DAY
AS THE NEXT TROUGH APPROACHES. MORNING CLOUD COVER WILL BE THE WILD
CARD FOR TEMPS AS IT MAY BE EXTENSIVE ALONG WITH SOME MORNING
FOG...BUT A DECREASE IS EXPECTED THROUGH LATE MORNING...WITH SOME
DIURNAL CU AND SOME APPROACHING CIRRUS FOR THE AFTERNOON. H85 TEMPS
WILL BE QUITE WARM RELATIVE TO RECENT DAYS...WITH READINGS AROUND
+16C. THIS COMBINED WITH EXPECTED INCREASE IN SUNSHINE DURING THE
AFTERNOON...AND A MODEST SOUTH-SOUTHWEST WIND SHOULD ALLOW FOR HIGHS
TO WARM INTO THE LOW TO MID 80S...WITH A FEW UPPER 80S POSSIBLE IF
CLOUD COVER IS LESS THAN FORECAST.
TUESDAY NIGHT AND WEDNESDAY...THE UPPER LOW OVER HUDSON BAY WILL
RE-POSITION ITSELF ACROSS EASTERN MANITOBA TUESDAY WITH ANOTHER
TROUGH AXIS ROTATING AROUND IT. THIS WILL PUSH ANOTHER WEAK COOL
FRONT SOUTHEASTWARD ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI
RIVER VALLEY INTO TUESDAY EVENING WHICH WILL THEN CROSS THE LOCAL
AREA EARLY WEDNESDAY. THIS FRONT LOOKS TO BE BETTER ORGANIZED THAN
THE ONE APPROACHING TONIGHT GIVEN THAT THE PARENT SFC LOW WILL BE
FURTHER SOUTH AND BETTER ORGANIZED AS IT CROSSES THE UPPER LAKES AND
CENTRAL ONTARIO. A MOIST AIRMASS WILL BE IN PLACE ACROSS THE AREA
WITH PRECIPITABLE WATER VALUES RUNNING BETWEEN 1.4 AND 1.7 INCHES.
IT APPEARS THAT THERE MAY BE SEVERAL SHORTWAVES THAT CROSS THE AREA
FROM TUESDAY EVENING THROUGH WEDNESDAY MORNING WITH THE MAIN FRONT
NOT PASSING UNTIL WEDNESDAY MORNING. WILL MAINTAIN THE LOW END
LIKELY POPS FROM THE PREVIOUS FORECAST BUT REFINE THE TIMING...WITH
THE BETTER CHANCES STARTING TUESDAY NIGHT. A DRYING TREND IS
EXPECTED WEDNESDAY AFTERNOON AS HIGH PRESSURE DROPS SOUTHEASTWARD
INTO THE AREA SHIFTING WINDS TO THE NORTH AND EAST. HIGHS MAY STILL
BE RATHER MILD WEDNESDAY WITH LOW TO MID 80S...THANKS TO THE UPPER
FLOW BEING ZONAL KEEPING MID LEVEL COOL ADVECTION AT A MINIMUM
THROUGH THE AFTERNOON. HOWEVER...TEMPS NEAR THE LAKESHORE WILL
LIKELY COOL AS WINDS TURN ONSHORE.
THURSDAY THROUGH THE WEEKEND...THE FRONT WILL STALL OUT SOUTH OF THE
AREA INTO EARLY THURSDAY WHILE HIGH PRESSURE MOVES OVERHEAD AND THEN
SHIFTS TO THE EAST. MID LEVEL COOL ADVECTION WILL BE UNDERWAY INTO
THURSDAY LEADING TO HIGHS BACK INTO THE MID TO UPPER 70S...WITH A
FEW 80S SOUTH. COOLEST READINGS WILL BE ALONG THE LAKESHORE AS
ONSHORE FLOW CONTINUES. ONE LAST TROUGH AXIS IS EXPECTED TO ROTATE
AROUND THE UPPER LOW OVER MANITOBA/ONTARIO. GUIDANCE IS LESS CLEAR
IN HOW THIS EVOLVES...WITH SOME SUGGESTION OF A STRONGER WAVE
THANKS TO PHASING OF ENERGY BETWEEN THE MAIN UPPER LOW AND ENERGY
OVERTOPPING A RIDGE ACROSS THE PACIFIC NORTHWEST. THIS WILL HAVE A
BIG IMPACT ON LOCAL POPS LATER THURSDAY AND FRIDAY AS A STRONGER
SYSTEM WOULD FORCE BETTER ORGANIZED SURFACE LOW/INVERTED TROUGH
DEVELOPMENT ACROSS THE MID MISSISSIPPI RIVER VALLEY ALONG THE OLD
FRONTAL BOUNDARY. THE STRONGER THE SURFACE LOW THE FURTHER NORTH THE
OLD BOUNDARY WILL MOVE AND THE GREATER THE CHANCES FOR PRECIP ACROSS
THE CWA. CONFIDENCE IS LOW GIVEN THAT THE UPPER FLOW PATTERN IS
ACTIVE BETWEEN NOW AND THEN AND ITS EVOLUTION MAY BE AFFECTED. AT
THE MOMENT IT APPEARS THAT THE BEST PRECIP CHANCES WILL BE SOUTH OF
THE AREA LATER THURSDAY/FRIDAY...WITH ANOTHER SURFACE HIGH BUILDING
IN INTO SATURDAY. HAVE BETTER CONFIDENCE IN THE MAIN UPPER LOW
MOVING EASTWARD WHICH WILL ALLOW RIDGING TO BUILD WEST AND A MORE
PRONOUNCED NORTHWEST FLOW ALOFT OF THE LOCAL AREA FOR THE WEEKEND.
THIS WILL LIKELY RESULT IN HIGHS THAT CONTINUE TO BE SEVERAL DEGREES
BELOW NORMAL. EXPECT DRY CONDITIONS SATURDAY BEFORE A SLIGHT INFLUX
IN MOISTURE ARRIVES SUNDAY/MONDAY WITH THE UPPER FLOW LOOKING TO
BECOME MORE ACTIVE. WILL LEAVE SUNDAY DRY FOR NOW.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* ISOLATED SHOWERS EARLY THIS MORNING.
* CIG TRENDS WITH MVFR CIGS DOWN AROUND 1500 FEET BY DAYBREAK.
* TIMING THE IMPROVEMENT OF THESE LOWER CIGS DURING THE MORNING.
* GOOD CHANCE OF TSRA TUESDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE PRIMARY FORECAST CONCERNS IN THE NEAR TERM WILL BE CIGS AND
VIS...ESPECIALLY THROUGH MID MORNING. ATTENTION THEN TURNS TO LATER
TONIGHT INTO WEDNESDAY MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A RATHER
COMPLICATED CIG AND VIS FORECAST OVERNIGHT...AS AREAS WHERE THE
CLOUDS ARE DISSIPATING LOWER CLOUDS AND FOG ARE DEVELOPING. CURRENT
THINKING IS THAT IT MAY TAKE A FEW MORE HOURS TO GET CIGS TO DROP
BELOW 2000 FT AGL AT THE EASTERN TAF SITES...AND WITH MORE CLOUD
COVER THE THREAT FOR FOG APPEARS LOW...ESPECIALLY AT ORD AND MDW.
THE FOG THREAT IS A BIT UNCERTAIN AT DPA AND RFD AS LOW CIGS MAY BE
THE RULE. HOWEVER...WITH VERY LOW DEW POINT DEPRESSIONS...IT WILL
NOT TAKE MUCH TO GET THE VIS TO TANK. WITH THIS IN MIND...I DECIDED TO
LEAVE THE TEMPO GROUPS FOR A PERIOD OF LOW VIS IN THE NEW TAF
FORECAST AT RFD AND DPA.
THERE HAVE AS BEEN A CONTINUED REDEVELOPMENT OF MAINLY SHOWERS
ACROSS FAR NORTHERN ILLINOIS AS THE FLOW ALOFT REMAINS RATHER
UNSETTLED. THIS WILL LIKELY CONTINUE TO BE THE CASE FOR THE NEXT FEW
HOURS ACROSS THE AREA. I EXTENDED THE VCSH TO ACCOUNT FOR THESE
SHOWERS. OVERALL THE THREAT FOR THUNDER WILL BE
LOW...HOWEVER...THERE HAVE BEEN A FEW STRIKES IN THE CELL ACROSS
STEPHENSON COUNTY. THIS CELL COULD APPROACH KRFD AFTER 07 UTC.
CIGS LOOK TO BE SLOW TO INCREASE THIS MORNING...BUT ONCE THEY
DO...THINGS SHOULD BE QUIET UNTIL TONIGHT. IT APPEARS LIKELY THAT A
COMPLEX OF THUNDERSTORMS WILL DEVELOP WEST OF THE AREA ACROSS IOWA
AND SOUTHWESTERN WISCONSIN DURING THE EVENING TODAY. THIS ACTIVITY
APPEARS THAT IT WILL MOVE OVER NORTHERN ILLINOIS LATER
TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY AT THE EASTERN TAF SITS.
I DID ADD A MENTION OF SHRA AND VCTS TO THE ORD 30 HR TAF AFTER 08
UTC. IT IS POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW
HOURS PRIOR TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE
TONIGHT INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE
APPROACHES THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN
THE AIRMASS AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN MVFR CIG/VIS CONDITIONS DEVELOPING
OVERNIGHT AND LINGERING THROUGH MID MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TUESDAY
NIGHT...WITH ONLY LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...CHANCE TSRA MAINLY MORNING. OTHERWISE VFR.
THURSDAY THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY SOUTH OF
CHICAGO THURSDAY NIGHT.
RATZER
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
133 AM CDT TUE AUG 6 2013
.DISCUSSION...
755 PM CDT
EVENING UPDATE:
MADE TWEAKS TO EVENING GRIDS TO BACK OFF TO ISOLATED SHRA MENTION
FOR APPROXIMATELY NORTHEASTERN HALF OF CWA. SHEARED OUT WAVE AND
MID LEVEL SPEED MAX CONTINUES TO PUSH ACROSS REGION WITH
SIGNIFICANT DRYING NOTED ON WATER VAPOR IN WAKE OF THIS WAVE.
LATEST RAP MESOANALYSIS HAS SHOWN IN INCREASE IN ELEVATED CAPE BUT
00Z DVN RAOB INDICATES THAT THIS IS LIKELY OVERDONE WITH VERY
MARGINAL INSTABILITY AND WEAK MID LEVEL LAPSE RATES ON THE
SOUNDING. WITH THE FORCING FROM THE MIDLEVEL WAVE
OVERHEAD...RETURNS OVER SOUTHWEST WISCONSIN HAVE INCREASED A BIT
IN RECENT SCANS BUT GIVEN THAT INSTABILITY FURTHER DIMINISHES INTO
OUR CWA...THIS ACTIVITY WILL LIKELY ONLY SURVIVE INTO CWA AS
SPOTTY PRIMARILY LIGHT SHOWERS. AN OUTSIDE CHANCE EXISTS FOR AN
ISOLATED T-STORM. THEN WENT WITH A DRY FORECAST AFTER MIDNIGHT FOR
ENTIRE AREA AS FORCING FROM VORT MAX WILL TRANSLATE EAST OF US BY
ABOUT MIDNIGHT.
ATTENTION WILL THEN TURN TO FOG POTENTIAL OVERNIGHT AS AIR MASS
REMAINS MOIST AND WINDS WILL CONTINUE TO DIMINISH. UNCERTAINTY AS
TO WHETHER STRATUS OR FOG IS THE PRIMARY MODE BUT IF BETTER CLEARING
CAN OCCUR...FOG WOULD BECOME MORE FAVORABLE AND EVEN POTENTIALLY
BECOME LOCALLY DENSE. OBS OVER SW WISCONSIN SHOW VSBY BETWEEN 2
AND 4 MILES AND LATEST GUIDANCE STILL SUPPORTS BEST CHANCE FOR
MORE WIDESPREAD FOG TO DEVELOP WELL WEST OF THE LAKEFRONT SO WILL
CONTINUE TO MONITOR OBSERVATIONAL TRENDS THIS EVENING AND MAKE
FURTHER UPDATES IF NEEDED. UPDATED ZONE PRODUCT HAS BEEN SENT.
RC
//PREV DISCUSSION...
312 PM CDT
A PREDOMINANTLY NORTHWESTERLY UPPER FLOW PATTERN WILL BE IN PLACE
THROUGH THE PERIOD WITH OCCASIONAL BUCKLING TO A MORE WESTERLY
DIRECTION OVER THE NEXT FEW DAYS. AS A RESULT...TIMING MODEST PRECIP
CHANCES WILL BE THE MAIN CHALLENGE THROUGH LATE WEEK. WATER VAPOR
IMAGERY SHOWS AN UPPER LOW CENTERED OVER SOUTHWESTERN PORTIONS OF
HUDSON BAY WHILE A LARGE UPPER ANTICYCLONE SPINS OVER TEXAS. BETWEEN
THE TWO...IS A BELT OF NORTHWESTERLY UPPER FLOW STRETCHED FROM THE
NORTHERN U.S. ROCKIES TO THE SOUTHEAST COAST. A CLOSER LOOK AT
SATELLITE SHOWS SEVERAL EMBEDDED SHORTWAVES WITHIN THIS FLOW...WITH
ONE HAVING PASSED OVER THE AREA EARLIER TODAY WITH ANOTHER
APPROACHING LATE THIS AFTERNOON. A LARGER SCALE TROUGH AXIS EXTENDS
FROM THE HUDSON BAY LOW WEST-SOUTHWEST WHERE A SMALLER SCALE
CIRCULATION IS NOTED OVER SOUTHERN ALBERTA. THIS WILL BE KEY IN OUR
WEATHER TUESDAY NIGHT AND WEDNESDAY. FURTHER WEST...ANOTHER UPPER
LOW IS CUTOFF OFF THE NORTHERN CALIFORNIA COAST AND MOVING VERY
LITTLE AS A RESULT. AT THE SURFACE...HIGH PRESSURE IS CENTERED OVER
EASTERN OHIO AND WESTERN PENNSYLVANIA WHILE A LOW IS CENTERED OVER
NORTHERN ONTARIO. A TROUGH AXIS EXTENDS SOUTHWARD FROM THE LOW INTO
EASTERN MINNESOTA AND IOWA.
THIS EVENING THROUGH TUESDAY...A WEAK SHORTWAVE CONTINUES TO CROSS
THE LOCAL AREA WITH A SMALL CLUSTER OF SHRA/TSRA WORKING
EAST-SOUTHEAST ACROSS THE FAR NORTHWEST ILLINOIS BORDER. THIS LOOKS
TO MAINTAIN ITSELF OVER THE NEXT FEW HOURS BUT LITTLE IF ANY LOW
LEVEL INSTABILITY HAS DEVELOPED THANKS TO AN EXTENSIVE...BUT
THINNING...CLOUD SHIELD. WHAT HAS DEVELOPED THOUGH SUGGESTS THAT
THIS CLUSTER WILL WORK SOUTHEAST TOWARD ROCKFORD...ROCHELLE...AND ON
INTO THE WESTERN/SOUTHWESTERN CHICAGO METRO IF IT MAINTAINS. IN
ADDITION...SOME SPOTTY ACTIVITY MAY DEVELOP AROUND THIS CLUSTER
INTO THE EVENING. A FEW STRONGER CORES HAVE POPPED UP FROM TIME TO
TIME IN THE LAST FEW RADAR SCANS WITH THE ACTIVITY BUT WITH SUCH
LIMITED INSTABILITY...THOUGH THERE IS STRONG SHEAR...MORE THAN AN
ISOLATED HAIL CORE OR WIND GUST LOOKS UNLIKELY. CHANCES WILL
DIMINISH THROUGH THE EVENING. THE AFOREMENTIONED TROUGH AXIS/COOL
FRONT MOVING ACROSS MINNESOTA WILL CONTINUE EASTWARD BUT FALL APART
WITH TIME OVERNIGHT. MID LEVEL DRYING IS EXPECTED OVERNIGHT AND WITH
NO COHERENT SOURCE OF FORCING DO NOT SEE MUCH CHANCE FOR PRECIP BY
LATE TONIGHT...IF NOT BEFORE THAT. THE AREA WILL BE BETWEEN SYSTEMS
TUESDAY WHICH SHOULD LEAD TO DRY CONDITIONS THROUGH AT LEAST THE
FIRST PART OF THE DAY BEFORE SMALL CHANCES INCREASE LATER IN THE DAY
AS THE NEXT TROUGH APPROACHES. MORNING CLOUD COVER WILL BE THE WILD
CARD FOR TEMPS AS IT MAY BE EXTENSIVE ALONG WITH SOME MORNING
FOG...BUT A DECREASE IS EXPECTED THROUGH LATE MORNING...WITH SOME
DIURNAL CU AND SOME APPROACHING CIRRUS FOR THE AFTERNOON. H85 TEMPS
WILL BE QUITE WARM RELATIVE TO RECENT DAYS...WITH READINGS AROUND
+16C. THIS COMBINED WITH EXPECTED INCREASE IN SUNSHINE DURING THE
AFTERNOON...AND A MODEST SOUTH-SOUTHWEST WIND SHOULD ALLOW FOR HIGHS
TO WARM INTO THE LOW TO MID 80S...WITH A FEW UPPER 80S POSSIBLE IF
CLOUD COVER IS LESS THAN FORECAST.
TUESDAY NIGHT AND WEDNESDAY...THE UPPER LOW OVER HUDSON BAY WILL
RE-POSITION ITSELF ACROSS EASTERN MANITOBA TUESDAY WITH ANOTHER
TROUGH AXIS ROTATING AROUND IT. THIS WILL PUSH ANOTHER WEAK COOL
FRONT SOUTHEASTWARD ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI
RIVER VALLEY INTO TUESDAY EVENING WHICH WILL THEN CROSS THE LOCAL
AREA EARLY WEDNESDAY. THIS FRONT LOOKS TO BE BETTER ORGANIZED THAN
THE ONE APPROACHING TONIGHT GIVEN THAT THE PARENT SFC LOW WILL BE
FURTHER SOUTH AND BETTER ORGANIZED AS IT CROSSES THE UPPER LAKES AND
CENTRAL ONTARIO. A MOIST AIRMASS WILL BE IN PLACE ACROSS THE AREA
WITH PRECIPITABLE WATER VALUES RUNNING BETWEEN 1.4 AND 1.7 INCHES.
IT APPEARS THAT THERE MAY BE SEVERAL SHORTWAVES THAT CROSS THE AREA
FROM TUESDAY EVENING THROUGH WEDNESDAY MORNING WITH THE MAIN FRONT
NOT PASSING UNTIL WEDNESDAY MORNING. WILL MAINTAIN THE LOW END
LIKELY POPS FROM THE PREVIOUS FORECAST BUT REFINE THE TIMING...WITH
THE BETTER CHANCES STARTING TUESDAY NIGHT. A DRYING TREND IS
EXPECTED WEDNESDAY AFTERNOON AS HIGH PRESSURE DROPS SOUTHEASTWARD
INTO THE AREA SHIFTING WINDS TO THE NORTH AND EAST. HIGHS MAY STILL
BE RATHER MILD WEDNESDAY WITH LOW TO MID 80S...THANKS TO THE UPPER
FLOW BEING ZONAL KEEPING MID LEVEL COOL ADVECTION AT A MINIMUM
THROUGH THE AFTERNOON. HOWEVER...TEMPS NEAR THE LAKESHORE WILL
LIKELY COOL AS WINDS TURN ONSHORE.
THURSDAY THROUGH THE WEEKEND...THE FRONT WILL STALL OUT SOUTH OF THE
AREA INTO EARLY THURSDAY WHILE HIGH PRESSURE MOVES OVERHEAD AND THEN
SHIFTS TO THE EAST. MID LEVEL COOL ADVECTION WILL BE UNDERWAY INTO
THURSDAY LEADING TO HIGHS BACK INTO THE MID TO UPPER 70S...WITH A
FEW 80S SOUTH. COOLEST READINGS WILL BE ALONG THE LAKESHORE AS
ONSHORE FLOW CONTINUES. ONE LAST TROUGH AXIS IS EXPECTED TO ROTATE
AROUND THE UPPER LOW OVER MANITOBA/ONTARIO. GUIDANCE IS LESS CLEAR
IN HOW THIS EVOLVES...WITH SOME SUGGESTION OF A STRONGER WAVE
THANKS TO PHASING OF ENERGY BETWEEN THE MAIN UPPER LOW AND ENERGY
OVERTOPPING A RIDGE ACROSS THE PACIFIC NORTHWEST. THIS WILL HAVE A
BIG IMPACT ON LOCAL POPS LATER THURSDAY AND FRIDAY AS A STRONGER
SYSTEM WOULD FORCE BETTER ORGANIZED SURFACE LOW/INVERTED TROUGH
DEVELOPMENT ACROSS THE MID MISSISSIPPI RIVER VALLEY ALONG THE OLD
FRONTAL BOUNDARY. THE STRONGER THE SURFACE LOW THE FURTHER NORTH THE
OLD BOUNDARY WILL MOVE AND THE GREATER THE CHANCES FOR PRECIP ACROSS
THE CWA. CONFIDENCE IS LOW GIVEN THAT THE UPPER FLOW PATTERN IS
ACTIVE BETWEEN NOW AND THEN AND ITS EVOLUTION MAY BE AFFECTED. AT
THE MOMENT IT APPEARS THAT THE BEST PRECIP CHANCES WILL BE SOUTH OF
THE AREA LATER THURSDAY/FRIDAY...WITH ANOTHER SURFACE HIGH BUILDING
IN INTO SATURDAY. HAVE BETTER CONFIDENCE IN THE MAIN UPPER LOW
MOVING EASTWARD WHICH WILL ALLOW RIDGING TO BUILD WEST AND A MORE
PRONOUNCED NORTHWEST FLOW ALOFT OF THE LOCAL AREA FOR THE WEEKEND.
THIS WILL LIKELY RESULT IN HIGHS THAT CONTINUE TO BE SEVERAL DEGREES
BELOW NORMAL. EXPECT DRY CONDITIONS SATURDAY BEFORE A SLIGHT INFLUX
IN MOISTURE ARRIVES SUNDAY/MONDAY WITH THE UPPER FLOW LOOKING TO
BECOME MORE ACTIVE. WILL LEAVE SUNDAY DRY FOR NOW.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* ISOLATED SHOWERS EARLY THIS MORNING.
* CIG TRENDS WITH MVFR CIGS DOWN AROUND 1500 FEET BY DAYBREAK.
* TIMING THE IMPROVEMENT OF THESE LOWER CIGS DURING THE MORNING.
* GOOD CHANCE OF TSRA TUESDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE PRIMARY FORECAST CONCERNS IN THE NEAR TERM WILL BE CIGS AND
VIS...ESPECIALLY THROUGH MID MORNING. ATTENTION THEN TURNS TO LATER
TONIGHT INTO WEDNESDAY MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A RATHER
COMPLICATED CIG AND VIS FORECAST OVERNIGHT...AS AREAS WHERE THE
CLOUDS ARE DISSIPATING LOWER CLOUDS AND FOG ARE DEVELOPING. CURRENT
THINKING IS THAT IT MAY TAKE A FEW MORE HOURS TO GET CIGS TO DROP
BELOW 2000 FT AGL AT THE EASTERN TAF SITES...AND WITH MORE CLOUD
COVER THE THREAT FOR FOG APPEARS LOW...ESPECIALLY AT ORD AND MDW.
THE FOG THREAT IS A BIT UNCERTAIN AT DPA AND RFD AS LOW CIGS MAY BE
THE RULE. HOWEVER...WITH VERY LOW DEW POINT DEPRESSIONS...IT WILL
NOT TAKE MUCH TO GET THE VIS TO TANK. WITH THIS IN MIND...I DECIDED TO
LEAVE THE TEMPO GROUPS FOR A PERIOD OF LOW VIS IN THE NEW TAF
FORECAST AT RFD AND DPA.
THERE HAVE AS BEEN A CONTINUED REDEVELOPMENT OF MAINLY SHOWERS
ACROSS FAR NORTHERN ILLINOIS AS THE FLOW ALOFT REMAINS RATHER
UNSETTLED. THIS WILL LIKELY CONTINUE TO BE THE CASE FOR THE NEXT FEW
HOURS ACROSS THE AREA. I EXTENDED THE VCSH TO ACCOUNT FOR THESE
SHOWERS. OVERALL THE THREAT FOR THUNDER WILL BE
LOW...HOWEVER...THERE HAVE BEEN A FEW STRIKES IN THE CELL ACROSS
STEPHENSON COUNTY. THIS CELL COULD APPROACH KRFD AFTER 07 UTC.
CIGS LOOK TO BE SLOW TO INCREASE THIS MORNING...BUT ONCE THEY
DO...THINGS SHOULD BE QUIET UNTIL TONIGHT. IT APPEARS LIKELY THAT A
COMPLEX OF THUNDERSTORMS WILL DEVELOP WEST OF THE AREA ACROSS IOWA
AND SOUTHWESTERN WISCONSIN DURING THE EVENING TODAY. THIS ACTIVITY
APPEARS THAT IT WILL MOVE OVER NORTHERN ILLINOIS LATER
TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY AT THE EASTERN TAF SITS.
I DID ADD A MENTION OF SHRA AND VCTS TO THE ORD 30 HR TAF AFTER 08
UTC. IT IS POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW
HOURS PRIOR TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE
TONIGHT INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE
APPROACHES THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN
THE AIRMASS AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN MVFR CIG/VIS CONDITIONS DEVELOPING
OVERNIGHT AND LINGERING THROUGH MID MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TUESDAY
NIGHT...WITH ONLY LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...CHANCE TSRA MAINLY MORNING. OTHERWISE VFR.
THURSDAY THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY SOUTH OF
CHICAGO THURSDAY NIGHT.
RATZER
&&
.MARINE...
240 PM...A BROAD WEAK TROUGH EXTENDING ACROSS THE PLAINS FROM A
SLIGHTLY STRONGER LOW OVER ONTARIO WILL SLOWLY MOVE EAST ACROSS
THE WESTERN LAKES WEDNESDAY...WITH THE LOW OVER ONTARIO SLOWLY
MOVING EAST THROUGH MID WEEK. AHEAD OF THIS TROUGH...SOUTHERLY
WINDS HAVE INCREASED TO 10-20 KT AND FORECAST SOUNDINGS SUGGEST
THE POTENTIAL FOR SOME WINDS INTO THE 15-25 KT RANGE THIS EVENING
BEFORE SLOWLY DIMINISHING OVERNIGHT. ONCE THE TROUGH/COLD FRONT
MOVES ACROSS THE LAKE MIDDAY WEDNESDAY...WINDS WILL SHIFT
NORTHERLY WITH A PERIOD OF 10-20 KTS POSSIBLE BUT APPEARS THAT
WOULD BE SHORT LIVED AS HIGH PRESSURE SPREADS ACROSS THE LAKES
REGION WEDNESDAY NIGHT INTO THURSDAY. THE LOW OVER ONTARIO FINALLY
SHIFTS EAST INTO QUEBEC ON FRIDAY...WITH A WEAK COLD FRONT MOVING
ACROSS THE WESTERN LAKES FRIDAY NIGHT SHIFTING WINDS BACK
NORTHERLY INTO SATURDAY WITH ANOTHER HIGH MOVING ACROSS THE LAKES
SATURDAY NIGHT INTO SUNDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CARIBOU ME
443 AM EDT TUE AUG 6 2013
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE COULD TRIGGER A SHOWER OR
THUNDERSTORM THIS AFTERNOON. OTHERWISE, HIGH PRESSURE WILL BUILD
ACROSS THE AREA TODAY AND MOVE EAST OF THE REGION ON WEDNESDAY AS
ANOTHER FRONT APPROACHES FROM THE SOUTHWEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
DRIER AND MILDER TODAY.
A WEAK RIDGE OF HIGH PRES AT THE SFC IS SET TO MOVE OVER THE
REGION TODAY INTO TONIGHT. DRIER WEATHER W/MORE SUNSHINE WILL BE
SEEN TODAY W/TEMPERATURES RESPONDING INTO THE MID AND UPPER 70S.
THE CAVEAT TO THIS HOWEVER WILL BE A WEAK S/WV IN THE UPPER LEVELS
THAT WILL MOVE ACROSS THE STATE THIS AFTERNOON. THIS FEATURE IS
PICKED UP WELL BY THE 00Z NAM AND CANADIAN GEM PER 06Z ANALYSIS
OVER ONTARIO. IR SATL IMAGERY SHOWED SOME MID/HIGH CLOUDS ASSOCIATED
W/THIS FEATURE MOVING INTO WESTERN AND NORTHERN NYS. GFS/NAM
SOUNDINGS AS WELL AS THE GEM SHOW SOME MOISTURE AT THE 850MB LEVEL
W/THE MAJORITY OF THE RH ABOVE 700MBS. LATEST TRAJECTORIES BRING
SOME CLOUDINESS`S ACROSS PORTIONS OF WESTERN AND NORTHERN AREAS
TODAY. SOUNDINGS DO INDICATE SOME INSTABILITY AS LIS DROP TO -1 TO
-3 AND SBCAPES HIT CLOSE TO 500 JOULES. THERE IS SOME WEAK SHEAR
AT 0-6KM OF 15 KTS OR SO. 850-700MB LAPSE RATES FROM THE NAM ARE
CLOSE TO 7.0 C/KM AND SOME LLVL CONVERGENCE NOTED. ALL THIS COULD
BE ENOUGH TO TRIGGER SOME ISOLD SHOWERS OR PERHAPS A TSTM MAINLY
FOR THE WESTERN AND NWRN AREAS. THE NAM AND GFS HINT AT THIS TO
SET UP. EVEN THE 06Z HRRR SHOWS WIDELY SCATTERED TO ISOLD PRECIP.
THEREFORE, DECIDED TO ADD THE MENTION OF A SHOWER OR POSSIBLE
TSTM INTO LATE AFTERNOON(20%).
ACTIVITY WILL WIND DOWN IN THE EVENING AS THE S/WV MOVES TO THE E
AND LOSS OF HEATING. HIGH PRES IN THE GULF OF MAINE WILL RIDGE
OVER THE REGION TONIGHT. CLEARING SKIES AND COOLER TEMPERATURES
WILL ALLOW FOR SOME FOG TO DEVELOP. OVERNIGHT LOWS ARE EXPECTED
TO DROP BACK INTO THE UPPER 40S ACROSS THE N AND NW WHILE LOWER
50S SHOULD DO IT FOR CENTRAL AND DOWNEAST AREAS.SATURATED GROUND
AND DAYTIME HEATING WILL AID IN THE FOG DEVELOPMENT. ATTM, WENT
W/PATCHY FOG. DAYCREW CAN ASSESS THIS FURTHER TODAY.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL MOVE EAST OF THE REGION DURING WEDNESDAY. AFTER A
MAINLY SUNNY START TO THE DAY EXPECT INCREASING HIGH CLOUDS IN
ADVANCE OF THE NEXT TROF APPROACHING FROM THE WEST. THE MAIN
CHANGE TO THE WEDNESDAY FORECAST WAS TO DELAY THE ONSET OF ANY
SHOWERS GETTING INTO THE WESTERN AREAS UNTIL WEDNESDAY EVENING.
HIGH TEMPERATURES ON WEDNESDAY WILL BE CLOSE TO NORMAL FOR THIS
TIME OF YEAR WITH MID 70S TO NEAR 80 DEGREES ACROSS THE REGION.
CLOUDS WILL CONTINUE TO INCREASE WEDNESDAY NIGHT WITH SHOWERS
DEVELOPING FROM WEST TO EAST AFTER MIDNIGHT IN ADVANCE OF AN
APPROACHING WARM FRONT. LOWS WEDNESDAY NIGHT ARE EXPECTED TO RANGE
FROM THE MID TO UPPER 50S ACROSS THE REGION.
SHOWERS WILL CONTINUE TO BE LIKELY ON THURSDAY IN ADVANCE OF THE
APPROACHING COLD FRONT. HIGH TEMPERATURES ON THURSDAY WILL BE A BIT
BELOW NORMAL FOR THIS TIME OF YEAR DUE TO THE COMBINATION OF CLOUDS
AND SHOWERS. HIGHS WILL RANGE FROM THE UPPER 60S TO NEAR 70 DEGREES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE WEAK SURFACE COLD FRONT WILL SLOWLY CROSS THE REGION THURSDAY
NIGHT WITH SHOWERS TAPERING OFF FROM WEST TO EAST AFTER MIDNIGHT.
THE WEAKENING FRONT WILL STALL NEAR OR ALONG THE COAST LATER
THURSDAY NIGHT AND FRIDAY. LATEST MODEL GUIDANCE SUGGESTS FRIDAY
MAY BE A MAINLY DRY ALTHOUGH MOSTLY CLOUDY DAY.
A VIGOROUS 500MB LOW WILL MOVE EAST INTO QUEBEC LATER FRIDAY AND
SATURDAY. MODELS DIVERGE ON THE OVERALL SENSIBLE WEATHER FOR LATER
FRIDAY NIGHT AND INTO SATURDAY. THE 00Z OP RUN OF THE GFS DEVELOPS A
COMPACT SURFACE LOW ACROSS NYS FRIDAY NIGHT AND THEN TRACKS IT
ACROSS NEW ENGLAND AND ACROSS DOWNEAST MAINE FRIDAY NIGHT. 00Z EC IS
FURTHER SOUTH AND WEAKER WITH THE LOW KEEPING THE REGION MAINLY DRY.
FOR NOW HAVE KEPT CONTINUITY WITH GOING FORECAST AND WENT WITH LOW
CHANCE POPS FRIDAY NIGHT AND INTO SATURDAY.
COOLER AND DRIER AIR WILL WILL FOLLOW FOR LATE WEEKEND AND INTO
EARLY NEXT WEEK WITH TEMPERATURES AVERAGING BELOW SEASONAL FOR THIS
TIME OF YEAR.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: VFR THROUGH TONIGHT FOR ALL TERMINALS. THERE IS
POTENTIAL FOR SOME FOG TO DEVELOP LATE TONIGHT MAINLY ACROSS THE
NORTHERN TERMINALS DUE TO THE WET GROUND AND CLEARING. CONDITIONS
COULD BRIEFLY DROP TO MVFR OR PERHAPS IFR BY EARLY WEDNESDAY MORNING.
SHORT TERM: VFR WEDNESDAY. MVFR WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT IN SHOWERS. VFR FRIDAY AND SATURDAY.
&&
.MARINE...
NEAR TERM: NO HEADLINES THIS TERM. WINDS WILL TURN TO THE SW LATER
TODAY AND AVERAGE 10 KT OR SO. WAVE HEIGHTS WILL STAY AT 2-3 FT
MAINLY AWAY FROM THE INTRA-COASTAL ZONE.
SHORT TERM: WINDS/SEAS SHOULD REMAIN BELOW SCA LEVELS FOR THIS
TIME OF YEAR.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT/DUDA
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
401 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN PARKED OFFSHORE THROUGH THE END OF THE
WEEK. SOUTHERLY RETURN FLOW AROUND THE HIGH WILL DRAW TROPICAL
MOISTURE UP THE EASTERN SEABOARD. A COLD FRONT IS EXPECTED TO MOVE
THROUGH THE MID-ATLANTIC STATES FRIDAY NIGHT AND SATURDAY. HIGH
PRESSURE BRIEFLY BUILDS IN LATE THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
WAVE WILL COME THRU BRINGING RAIN SHOWERS MAINLY TO CENTRAL VA AND
SOUTHERN MD OVERNIGHT INTO THE MORNING...MAINTAINING THE CHANCE IT
COULD EDGE FURTHER NORTH AS IT MOVES EAST SOUTHEAST ACROSS THE
REGION. HRRR SEEMS TO HAVE THE BEST HANDLE ON THIS EVOLVING
SITUATION BASED ON EARLY MORNING RADAR TRENDS.
AFTER THAT WAVE SLIDES EAST OF US BY MID TO LATE MORNING. MOST
MESOMODELS SHOW SCATTERED CONVECTION DEVELOPING IN THE WARM
ADVECTION ENVIRONMENT FOR THE AFTERNOON AND TUE NIGHT FAIRLY
EVENLY ACROSS THE FORECAST AREA. GIVEN THE WEAK AND DIFFUSE
FORCING WITH THIS...AM NOT CURRENTLY ABLE TO PUT MUCH DETAIL INTO
WHERE THE BEST CHANCES ARE IN TIME AND AREA.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
A CLOSED LOW WILL MEANDER OVER MANITOBA WHILE AN UPPER RIDGE IS
PARKED OVER THE GULF COAST STATES THRU THE SHORT-TERM PERIOD. UPPER
FLOW PATTERN BETWEEN THESE TWO SYSTEMS WILL BE FAIRLY ZONAL DURING
THIS TIME WITH THE MID-ATLANTIC REGION SITUATED ON SRN PERIPHERY OF
STRONGER WESTERLIES. A SERIES OF SHORTWAVE DISTURBANCES WILL ROTATE
AROUND THE BASE OF THE UPPER TROUGH WITHIN THIS BELT OF ENHANCED
WESTERLIES DURING THE SECOND HALF OF THE WEEK.
IN THE LLVLS AND AT THE SFC...SLY RETURN FLOW AROUND HIPRES OVER THE
WRN ATLANTIC WILL TRANSPORT MOISTURE FROM THE CARIBBEAN UP THE ERN
SEABOARD. PWATS INCREASE FROM AROUND 1.5 INCHES WED MRNG TO 2 INCHES
BY THU. IT WILL NOT REQUIRE A WHOLE LOT OF FORCING FROM EACH
SHORTWAVE TROUGH TO PRODUCE SHOWERS AND TSTMS IN THIS TROPICAL
AIRMASS. LOWERED POPS A BIT FROM PREV FCST WITH THE BEST FORCING
EXPECTED TO REMAIN NORTH AND WEST OF THE AREA DURING THE SHORT TERM.
POPS CLOSELY FOLLOW DIURNAL CYCLE AND ARE HIGHEST EACH DAY DURING
THE AFTN/EVE HRS. WITH EXTENSIVE CLOUD COVER OVER THE AREA...THERE
IS SOME FCST UNCERTAINTY REGARDING TSTM COVERAGE...WHICH WILL DEPEND
ON AMT OF DAYTIME HEATING. ANY STORMS WILL HAVE THE POTENTIAL TO
PRODUCE LOCALLY HVY RAINFALL...ESPECIALLY ON THU.
HUMID AIRMASS AND CLOUDS COVER WILL YIELD BELOW NORMAL HIGHS AND
ABOVE NORMAL LOWS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE VERTICALLY-STACKED LOW WILL PROGRESS SLOWLY EWD ACROSS CENTRAL
ONTARIO FRI. A LEADING SHORTWAVE DISTURBANCE ROTATING AROUND THE
BASE OF THE LARGE-SCALE TROUGH IS FCST TO MOVE FROM THE GREAT
LAKES/OH VLY TO THE NRN MID-ATLANTIC AND NORTHEAST STATES DURING
THIS TIME. THIS DISTURBANCE WILL PROVIDE SOME WEAK LIFT FOR
SHOWERS AND STORMS ESPECIALLY DURING THE PEAK HEATING HRS. YDA`S
MODELS SHOWED A COLD FRONT BECOMING STALLED OVER THE AREA ON FRI.
NOW...THE LATEST 00Z ECMWF...GFS AND ITS ENSEMBLE MEMBERS INDICATE
THE BOUNDARY REMAINING NORTH OF THE AREA. GIVEN THE SLOWING
TREND...POPS WERE LOWERED AND THE POTENTIAL FOR MORE WIDESPREAD
HEAVY RAIN NOT AS HIGH AS IT APPEARED TO BE YDA.
NONETHELESS...PWATS WILL BE ABOVE 2 INCHES...SO ANY STORMS THAT
DEVELOPS WILL BE EFFICIENT RAINFALL PRODUCERS. CONVECTION FRI AFTN
MAY FOCUS ALONG A LEE TROUGH THAT FORMS AHEAD OF THE MAIN COLD
FRONT.
THE AFOREMENTIONED SHORTWAVE TROUGH WILL MOVE ACROSS NRN NEW ENGLAND
FRI NGT. NW FLOW BEHIND THE TROUGH WILL HELP PUSH THE COLD FRONT
TOWARD THE MASON-DIXON LINE LATE FRI NGT. DIURNALLY-DRIVEN
CONVECTION EXPECTED TO WANE AFTER SUNSET.
WITH A LATER TIMING IN THE FROPA AND COOLER...DRIER AND MORE STABLE
AIR LAGGING BEHIND THE FRONT...FCST HAS TRENDED WETTER FOR THE SRN
HALF OF THE CWA ON SAT. EXPECT SHOWERS AND STORMS TO DEVELOP DURING
THE PEAK HEATING HRS. THE HIGHEST POPS RESIDE OVER THE CENTRAL VA
AND LWR SRN MD...WHICH WILL BE LOCATED CLOSEST TO LLVL CONVERGENCE
NEAR THE FRONT.
THE FRONTAL BOUNDARY IS EXPECTED TO STALL SOUTH OF THE AREA ON SUN
BEFORE LIFTING BACK NORTHWARD AS A WARM FRONT ON MON. DRY WEATHER TO
CLOSED OUT THE WEEKEND WILL BE SHORT LIVED AS SHOWERS AND STORMS
RETURN ERY NEXT WEEK.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
EXPECTING MVFR CONDITIONS TO MOVE IN THIS MORNING AND LAST INTO
WED. SHOWER THREAT WILL BE THERE..ESP FOR CHO THIS MORNING. ALSO
AN ISOLATED CHANCE FOR A TSTM.
MOIST SLY RETURN FLOW WILL BE ACCOMPANIED BY DAILY CHANCES FOR SHRA
AND TSRA DURING THE SECOND HALF OF THE WEEK. CONVECTION WILL BE
PREDOMINANTLY DIURNALLY-DRIVEN AND SCT IN NATURE. THE POTENTIAL IS
THERE FOR PERIODS OF LOW CLOUDS AND FOG EACH NGT/ERY MRNG GIVEN THE
MOIST BOUNDARY LAYER IN PLACE. A COLD FRONT MOVES THRU THE TERMINALS
FRI NGT AND SAT.
&&
.MARINE...
SCA HAS BEEN ISSUED FOR LATER TODAY INTO WED FOR THE BAY CHANNEL S
OF ANNAP AND THE LOWER TIDAL POTOMAC.
SCA HAS BEEN EXTENDED INTO WED FOR MOST OF THE MD CHSPK BAY AND THE
MOUTH OF THE TIDAL POTOMAC. SLY FETCH WILL PROMOTE CHANNELING IN
THESE ZONES.
HIPRES MOVES FARTHER OFFSHORE THU AND FRI. CHANNELING WILL STILL
ENHANCE WIND SPEEDS TO AROUND 15 KT IN THE BAY.
&&
.TIDES/COASTAL FLOODING...
SLY FLOW WILL CONTINUE THROUGH THE END OF THE WEEK AS HIGH PRESSURE
REMAINS OFF THE EAST COAST. THE HIGHER OF THE HIGH TIDE WILL BE THE
ONE TO WATCH FOR POTENTIAL MINOR TIDAL FLOODING WITH THE NEW MOON
EXPECTED MID WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...COASTAL FLOOD ADVISORY UNTIL 9 AM EDT THIS MORNING FOR MDZ014.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 8 AM EDT
WEDNESDAY FOR ANZ532>534-537-540>543.
&&
$$
SYNOPSIS...JRK
NEAR TERM...CAS
SHORT TERM...JRK
LONG TERM...JRK
AVIATION...JRK/CAS
MARINE...JRK/CAS
TIDES/COASTAL FLOODING...JRK/CAS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
247 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC STATES MOVES OFF THE COAST
TONIGHT AND TUESDAY. A WARM FRONT WILL LIFT BACK NORTH INTO THE
REGION LATE TONIGHT THROUGH TUESDAY. A MOIST AIR MASS WILL PREVAIL
THE REST OF THE WEEK...RESULTING IN DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TODAY/...
THE LATEST WATER VAPOR IMAGERY ALONG WITH 00Z UPPER AIR
OBSERVATIONS INDICATE NW MID/UPPER FLOW FROM THE UPPER MIDWEST
THROUGH THE MID ATLANTIC BETWEEN TWO PRIMARY TROUGHS OVER CENTRAL
AND ATLANTIC CANADA...AND AN UPPER RIDGE CENTERED OVER TX. WV
IMAGERY INDICATES A SHORTWAVE TROUGH DIVING ESE ACROSS THE LOWER
GREAT LAKES. WAA RETURNS AHEAD OF THIS FEATURE LATE TONIGHT ALONG
WITH ISENTROPIC LIFT AROUND THE 305-310K RANGE. IN EFFECT...THE
80H WARM FRONT WILL PASS THROUGH THE AREA TUESDAY MORNING. THIS
WILL BEGIN OVER THE MOUNTAINS OF SOUTHWEST VIRGINIA AND DEVELOP TO
THE E AND NE. THE LAST FEW RUNS OF THE RUC ALONG WITH SUPPORT FROM
THE 18Z NAM/GFS INDICATE RATHER STRONG LIFT OVER THE NW QUADRANT
OF THE CWA LATE TONIGHT INTO EARLY TUESDAY MORNING (08-12Z). GIVEN
THIS...POPS WERE RAISED TO LIKELY FOR THE NW CORNER OF THE AREA
DURING THIS TIMEFRAME. OTHERWISE...POPS REMAIN AS IS FOR REST OF
THE AREA.
LOW TEMPERATURES WILL RANGE FROM THE LOWER 60S ON THE LOWER EASTERN
SHORE TO THE MID AND UPR 60S ELSEWHERE.
ON TUESDAY...FOLLOWED CLOSE TO NAM FORECAST. BOTH THE NAM AND MOS
GUIDE HAVE THE HIGHEST POPS OVER THE FAR NORTH PART OF OUR AREA
(DORCHESTER COUNTY MD AND PART OF THE NORTHERN NECK). HAVE LIKELY
POPS IN THIS AREA THROUGH EARLY TUESDAY AFTN. A CHANCE FOR SHOWERS
AND THUNDERSTORMS WILL EXTEND ACROSS THE CWA TUESDAY AFTN WITH
LOWEST POPS (20 PERCENT) JUST ALONG THE ALBEMARLE SOUND. KEPT
THUNDERSTORM MENTION TO SLIGHT CHANCE UNTIL 18Z TUESDAY.
TEMPERATURES WILL BE HELD DOWN SOME BY CLOUD COVER AND PCPN WITH
READINGS AROUND 80 IN THE NORTH TO THE MID 80S NEAR THE VA/NC
BORDER.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
CONTINUED WITH THE CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH MOST
OF THE SHORT TERM PERIOD. MOST POPS ARE IN THE 30 TO 40 PERCENT
RANGE. DEEPEST MOISTURE APPEARS TO BE OVER THE NORTHWEST HALF OF THE
AREA. SOME LOCALLY HEAVY RAINFALL IS POSSIBLE...MAINLY WEST OF I95
AND ACROSS THE NORTHERN COUNTIES...BUT DO NOT SEE A NEED TO
HIGHLIGHT IN THE HWO AT THIS POINT.
HIGHEST CHANCES APPEAR TO BE WEDNESDAY NIGHT WHEN MOST MODELS
INDICATE A SHORT WAVE MOVING THROUGH. WITH THIS BEING IN THE FIFTH
PERIOD...HIGHEST CHANCES ARE ACROSS OUR NORTHERN AREAS...SIMILAR TO
TUESDAY MORNING. WAS NOT CONFIDENT ENOUGH WITH THE TIMING TO GO
LIKELY AT THIS POINT. HIGH TEMPERATURES WEDNESDAY ARE FORECAST TO BE
IN THE LOW TO MID 80S WEDNESDAY AND MID 80S TO NEAR 90 ON THURSDAY.
LOWS SHOULD RANGE FROM 65 TO 70.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MEDIUM RANGE MODELS CONTINUE TO HANDLE THE OVERALL UPPER PATTERN
WELL. STRONG UPPER LEVEL CLOSED LOW WILL BEGIN TO EJECT EWD FRI AS A
SPEED MAX ROUNDS THE BASE OF THE LOW...AMPLIFYING A MID LEVEL TROUGH
OVER THE NE STATES. THE EJECTING LOW WILL PUSH A SFC LOW THRU SE
CANADA WITH AN ATTENDANT COLD FRONT STRETCHING SWWD INTO THE OH
VALLEY. MEANWHILE...MID LEVEL HIGH PRESSURE WILL LOCATE JUST OFF THE
SOUTHEAST COAST FRI WITH RIDGING OVER THE WRN ATLANTIC. THE RESULT
WILL BE INCREASING SW FLOW OVER THE LOCAL AREA. PRECIP WATER VALUES
PROGGED TO INCREASE AOA 2 INCHES FRI AFTERNOON WITH STRONG H85
MOISTURE TRANSPORT. SHORTWAVE ENERGY EMBEDDED IN THE WSW FLOW ALOFT
WILL PROVIDE SUBTLE FORCING FOR ASCENT FRI AFTERNOON. LEE SIDE
TROUGH AND THE APPROACHING COLD FRONT...AS WELL AS LOCAL CONVERGENCE
BOUNDARIES...WILL COMBINE WITH MID LEVEL FORCING AND ABUNDANT
MOISTURE FOR SCATTERED SHOWERS AND THUNDERSTORMS FRI AFTERNOON. THE
BEST COVERAGE WILL BE OVER THE PIEDMONT...CLOSEST TO THE FRONT AND
BEST MOISTURE. HIGH PRESSURE AND LESS MOISTURE ALONG THE COAST WILL
LIMIT PRECIP CHANCES ACROSS THE SE. AS THE UPPER LEVEL FORCING WANES
FRI NIGHT IN ADVANCE OF THE FRONT...EXPECT PRECIP CHANCES TO
DIMINISH LATE FRI NIGHT/EARLY SAT MORNING. THE FRONT WILL SAG SWD
THROUGH THE LOCAL AREA SAT. ADDITIONAL SHORTWAVE ENERGY AS WELL AS
RRQ OF 70 KT UPPER LEVEL JET WILL PROVIDE BETTER FORCING FOR ASCENT
SAT ALONG THE COLD FRONT...RESULTING IN BETTER COVERAGE (ALBEIT
CHANCE) OF SHOWERS AND THUNDERSTORMS OVER THE LOCAL AREA. REGARDLESS
OF ABUNDANT MOISTURE (+1 TO +2 STD DEV PRECIP WATER) AND LIMITED
FORCING FOR ASCENT...THE BEST DYNAMICS WILL REMAIN WELL NORTH OF THE
LOCAL AREA. THIS WILL LIKELY LIMIT THE COVERAGE OF
SHOWERS/THUNDERSTORMS...BUT LOCALLY HEAVY RAINFALL WILL STILL BE
POSSIBLE DUE TO THE VERY MOIST AIRMASS. FLOW PARALLEL TO THE FRONT
AND HIGH PRESSURE ALONG THE SE COAST WILL RESULT IN THE FRONT
SLOWING AS IT REACHES THE COAST. WILL HOLD ONTO SLIGHT CHANCE-CHANCE
POPS ACROSS THE SE SUN TO ACCOUNT FOR THE SLOWING FRONT. HIGH
PRESSURE WILL THEN BUILD IN BEHIND THE DEPARTING COLD FRONT.
HOWEVER...COLDEST AIR EXPECTED TO REMAIN NORTH OF THE LOCAL AREA.
MAIN CHANGES POST FRONTAL WILL BE DRIER AIR AND NLY WINDS.
TEMPS DURING THE EXTENDED WILL REMAIN AROUND SEASONABLE NORMS
(MID/UPPER 80S) UNDER PARTLY CLOUDY TO MOSTLY CLOUDY SKIES. MILD
OVERNIGHT TEMPS WITH LOWS GENERALLY IN THE UPPER 60S/LOW 70S. HUMID
FRI-SAT BEFORE DRYING OUT POST FRONTAL SAT NIGHT-MON.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS CONTINUE TO PREVAIL EARLY THIS MORNING ACROSS AREA
TERMINALS. HAVE NOTED SOME LOWERING CEILINGS OVER THE PAST 2 HOURS
AHEAD OF AN APPROACHING WARM FRONT. EXPECT BKN/OVC CONDITIONS
BETWEEN 4-6KFT BETWEEN 08-12Z. AFTER A BRIEF PERIOD OF VICINITY
SHRAS, HV CONTINUED PREDOMINATE -RA MENTION AT KRIC/KPHF/KSBY
THROUGH 12Z. DUE TO DRY AIR IN LLVLS, WILL KEEP VSBYS P6SM AND
CIGS AOA 3KFT. WINDS SHIFT FROM SE TO S/SW THIS AFTN WITH THE
POTENTIAL FOR AT LEAST SCATTERED SHRA OR TSRA BUT GIVEN
UNCERTAINTY WENT WITH ANOTHER PERIOD OF "VCSH" IN TAFS FOR NOW.
OTHERWISE...MODESTLY WARMER AND MORE HUMID AIRMASS WILL PREVAIL
FOR THE MID TO LATTER PORTION OF THE WORK WEEK. SCT (MAINLY
DIURNALLY DRIVEN) SHOWERS AND TSTMS ARE EXPECTED. COLD FRONT
SLOWLY PUSHES THROUGH ON SAT...BRINGING WITH IT CONTINUED CHANCES
FOR SHRA/TSRA.
&&
.MARINE...
LIGHT N-NE WINDS AOB 10 KT OVER THE WATERS TODAY AS HIGH PRESSURE
ORIENTS ALONG THE MID ATLANTIC COAST. HIGH PRESSURE WILL CONTINUE
TO SLIDE OFFSHORE TONIGHT AS WINDS TURN TO THE S-SE. A WARM FRONT
WILL LIFT THROUGH THE MID ATLANTIC REGION LATE TUE-WED. WINDS WILL
INCREASE BEHIND THE FRONT AS THE GRADIENT TIGHTENS BTWN HIGH
PRESSURE OFFSHORE AND LOW PRESSURE OVER THE GREAT LAKES
REGION...BUT ARE EXPECTED TO REMAIN BELOW SCA SPEEDS. SOME SLY
CHANNELING MAY LEAD TO ENHANCED WINDS OVER THE MIDDLE BAY TUES
NIGHT-WED. GRADIENT WILL REMAIN THROUGH THURS WITH SLY WINDS AOB
15 KT. S-SE WINDS OVER THE COASTAL WATERS WILL BUILD SEAS 3-5 FT
WED NIGHT-THURS OVER THE NRN COASTAL ZONES BEFORE DIMINISHING
THURS EVENING. UNSETTLED CONDITIONS WILL REMAIN OVER THE WATERS
THROUGH EARLY THIS WEEKEND AS A COLD FRONT APPROACHES FROM THE
NORTHWEST. THE FRONT IS EXPECTED TO REACH...AND STALL OVER THE
WATERS SAT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LSA
NEAR TERM...AJZ/LSA
SHORT TERM...LSA
LONG TERM...SAM
AVIATION...LKB/MAM
MARINE...SAM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
548 AM EDT TUE AUG 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 548 AM EDT TUE AUG 6 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN UNUSUALLY DEEP VORTEX
FOR EARLY AUG CENTERED JUST S OF HUDSON BAY ALONG THE
MANITOBA/ONTARIO BORDER. ACROSS THE UPPER LAKES...FLOW HAS BECOME
MORE WESTERLY OVER THE LAST DAY OR TWO IN RESPONSE TO THE
DEEPENING/EXPANDING VORTEX THAT HAS BEEN DRIFTING S. SEVERAL
SHORTWAVES ARE EVIDENT UPSTREAM WITH 2 MORE NOTABLE WAVES OVER ERN
MT/SRN SASKATCHEWAN AND OVER ERN ALBERTA. THESE 2 WAVES WILL POWER A
COLD FRONT ACROSS UPPER MI TONIGHT AND WEDNESDAY MORNING. CLOSER TO
HOME...ISOLD/SCT SHRA (EVEN ISOLD TSRA AT TIMES) HAVE BEEN OCCURRING
OVER THE LAST SEVERAL HRS OVER WRN UPPER MI/ADJACENT LAKE SUPERIOR.
THESE SHRA ARE JUST AHEAD OF A 700MB TROF AND SURGE OF MIDLEVEL
DRYING PER BY LATEST RUC.
FOCUS EARLY THIS MORNING WILL BE ON THE ISOLD/SCT SHRA OVER THE W.
AS AFOREMENTIONED 700MB TROF CONTINUES TO PUSH E...WILL PROBABLY
CONTINUE TO SEE SOME SHRA SPREAD E INTO CNTRL UPPER MI OVER THE NEXT
SEVERAL HRS. LATEST SPC MESOANALYSIS SHOWS MUCAPE AROUND 250J/KG...
SO THERE MIGHT BE AN OCNL LIGHTNING STRIKE THOUGH THERE HAS NOT BEEN
ANY CG STRIKES FOR THE LAST COUPLE OF HRS. AS THE TROF CONTINUES
EASTWARD...IT WILL COINCIDE WITH THE HEATING CYCLE AND SHOULD AID
SHRA/TSRA DEVELOPMENT OVER THE ERN PART OF THE FCST AREA LATE THIS
MORNING/EARLY THIS AFTN...ESPECIALLY INLAND FROM LAKE MICHIGAN. SOME
HIGH RES GUIDANCE (NAM NEST AND RUC13) INDICATE LAKE BREEZE WILL
DEVELOP OFF LAKE SUPERIOR OVER THE E...BUT WILL MAKE LIMITED INLAND
PROGRESS. IF SO...CONVERGENCE ZONE WILL BE A GOOD FOCAL POINT FOR
CONVECTION. TO THE W ACROSS THE W HALF OF UPPER MI...THE SAME HIGH
RES GUIDANCE POINTS TO A MORE ACTIVE INLAND PUSH OF LAKE SUPERIOR
LAKE BREEZE. IN THE FLOW UPSTREAM...THERE ARE PROBABLY SOME SUBTLE
SHORTWAVES PRESENT GIVEN THE SCT CLUSTERS OF SHRA/TSRA THAT WERE
PRESENT EARLIER IN THE NIGHT ACROSS THE NRN PLAINS. WITH EXPECTATION
OF LOW CLOUDS CLEARING OUT/TRANSITIONING TO CU FIELD...DAYTIME
HEATING WILL LIKELY BE SUFFICIENT TO RAISE MLCAPE TO 500J/KG OR SO
PER NAM/GFS. LAKE BREEZE AND ANY SUBTLE SHORTWAVES SHOULD THEN
SUPPORT SCT SHRA/TSRA DEVELOPMENT. WITH DEEP LAYER SHEAR AROUND
35KT...SOME ORGANIZED/STRONGER STORMS ARE POSSIBLE. IF CAPE ENDS UP
HIGHER THAN CURRENTLY EXPECTED...THERE MIGHT BE AN ISOLD SVR STORM
OR TWO.
TONIGHT...THE STRONGER SHORTWAVES WELL UPSTREAM WILL PUSH A COLD
FRONT INTO UPPER MI. AS HAS BEEN THE CASE FOR THE LAST SEVERAL
DAYS...MODELS CONTINUE TO POINT TOWARD A GOOD POTENTIAL OF SHRA/TSRA
SPREADING ACROSS THE FCST AREA. WITH RATHER VIGOROUS DEEP LAYER
FORCING...STRONG MOISTURE TRANSPORT AND SHARP LOW LEVEL TROF
SHIFTING E...WILL RETAIN LIKELY POPS SPREADING E ACROSS THE AREA
TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 548 AM EDT TUE AUG 6 2013
AMPLIFIED UPPER AIR PATTERN PERSISTS THROUGH THE UPCOMING WEEKEND
AND LIKELY INTO NEXT WEEK AS WELL. MEAN TROUGHING DOMINATES MUCH OF
EASTERN CANADA ACROSS THE GREAT LAKES. PRIMARY RESULT OF THIS
PATTERN WILL BE CONTINUATION OF COOLER THAN NORMAL TEMPERATURES
THROUGH AT LEAST MID AUGUST ACROSS UPPER GREAT LAKES REGION. TO
START OUT ON WEDNESDAY...MAIN FEATURES ALOFT ARE CLOSED OFF UPPER
LOW CENTERED ALONG MANITOBA AND NORTHERN ONTARIO BORDER...SHARP WEST
TO EAST RIDGE OVER FAR NORTHERN CANADA AND A DOUBLE BARRELED TROUGH
EXTENDING FROM THE NORTH POLE SOUTHWEST ACROSS ALASKA AND TO THE
NORTHERN PORTIONS OF PACIFIC OCEAN. NOT A WHOLE LOT OF CHANGE WRT
LOCATIONS OF SAID FEATURES THROUGH THE LONG TERM. ONLY THING THAT
DOES CHANGE IS UPPER LOW OVER ONTARIO SLIDES ACROSS QUEBEC THIS
WEEKEND AS STRONGER JET ENERGY BECOMES PLACED OUT AHEAD OF THE
TROUGH...KEEPING IT MORE PROGRESSIVE. MAIN CHANCE OF RAIN IN THIS
PATTERN WILL BE RIGHT OFF THE BAT ON WEDNESDAY MORNING OVER EAST
HALF OF CWA AS COLD FRONT MOVES THROUGH REGION. ADDITIONAL CHANCES
OF RAIN POSSIBLE THURSDAY NIGHT INTO FRIDAY AS SECONDARY LOW PRESSURE
SYSTEM AND COLD FRONT CROSS THE AREA. GENERALLY LOOKS QUIET THROUGH
THE WEEKEND...BUT COOL. NEXT CHANCE OF RAIN PROBABLY ARRIVES LATER
SUNDAY NIGHT INTO MONDAY AS SHORTWAVES DROP ACROSS AREA IN NW FLOW
ALOFT.
COLD FRONT SHOULD BE OVER CNTRL UPR MICHIGAN TO START THE DAY ON
WEDNESDAY...QUICKLY HEADING EAST TO AROUND ERY BTWN 15Z-18Z. NAM
STILL ON THE FAST SIDE...WHILE ECMWF IS SLOWEST. COMPROMISE SOLN
WITH FRONT IS THE GFS/GEM-REGIONAL AS WELL AS NCEP WRF-ARW/NMM.
MAJORITY OF WIDESPREAD SHRA/TSRA WILL BE ALONG AND AHEAD OF FRONT
IN WARM AIR ADVECTION REGIME. GOING FCST LOOKS PRETTY GOOD.
CHANGES TO POPS ON WEDNESDAY WITH FROPA PRETTY MINIMAL. KEPT
LIKELY POPS OVR FAR EAST THROUGH 15Z...THEN TRIMMED BACK QUICKLY
WITH ARRIVAL OF STRONG MID-LEVEL DRYING AND AS PRIMARY H85 MOISTURE
ADVECTION IS EAST OF CWA. SOUNDINGS INDICATE LINGERING LOW-LEVEL
MOISTURE BEHIND COLD FRONT THAT COULD LEAD TO BRIEF PERIOD OF LGT
RAIN/DRIZZLE IN THE MORNING FOR AREAS NEAR LK SUPERIOR.
EVENTUALLY...BLYR BECOMING MIXED ALONG WITH NEGATIVE SFC-H85 THETA-E
ADVECTION WILL SHUT DOWN ANY LINGERING PRECIP BY MIDDAY. HAVE NO
POPS AFTER 18Z WHICH WAS A BIT OF A CHANGE COMPARED TO PREVIOUS
FCST. BKN CU/SC DECK MAY REMAIN LONGER THAN THIS...BUT EVEN THAT
SHOULD TEND TO MIX OUT TO PARTLY CLOUDY SKIES BY MID-LATE AFTN.
TEMPS TRICKY WITH FROPA AS 925-850MB TEMPS JUST AHEAD OF FRONT ARE
PRETTY WARM. FIGURING OUT HOW THE WARM AIR BALANCES BTWN COOLING
FROM CLOUDS/PRECIP IS MAIN HURDLE. WILL GO FOR MAX TEMPS TOPPING OUT
IN THE LOW 70S...WARMEST SOUTH CENTRAL. TEMPS ALONG LK SUPERIOR
COULD RISE EARLY ON...BUT THEN FALL BACK IN THE AFTN WITH INCREASING
ONSHORE FLOW. SHOULD BE ESPECIALLY NOTABLE NEAR MQT-P53. FOG THAT IS
DEVELOPING ACROSS LK SUPERIOR CURRENTLY MAY GET SHOVED ONSHORE TOO
FOR A WHILE.
SFC HIGH RIDGES IN FROM CANADIAN PRAIRIE PROVINCES WEDNESDAY NIGHT
INTO THURSDAY AHEAD OF NEXT COLD FRONT. H85 WINDS STAY ONSHORE ALL
NIGHT...BUT LOWEST LEVEL WINDS THROUGH 900MB BECOME LESS
SO...ALLOWING POTENTIAL FOR TYPICAL COOL SPOTS INLAND FROM THE GREAT
LAKES TO SEE TEMPS FALL INTO THE LOWER 40S. LIGHT GRADIENT WINDS ON
THURSDAY ALLOWS IN LIGHT LAKE BREEZES ALONG BOTH SUPERIOR AND
MICHIGAN. AWAY FM LOCAL COOLING THOUGH...TEMPS SHOULD BOUNCE BACK
INTO AT LEAST THE LOWER 70S MOST AREAS GIVEN H85 TEMPS WARMER THAN
+10C. THICKENING MID CLOUDS /H6-H5/ FOR WEST HALF BY AFTN AS WARM
AIR ADVECTION DEVELOPS AHEAD OF THE COLD FRONT. GFS HAS SHOWED
STEADY TREND IN BACKING OFF QPF INTO WESTERN TIER. USED A BLEND OF
MORE CONSISTENT ECMWF AND THE DRIER TRENDING GFS. RESULT WAS SOME
LOWER CHANCE POPS FOR WESTERN LK SUPERIOR/ISLE ROYALE ON NOSE OF
H85-H7 MOISTURE ADVECTION. AS SFC LOW SPINS OVER NORTHERN ONTARIO
THE COLD FRONT WILL SLOWLY SINK NORTH TO SOUTH ACROSS LK SUPERIOR
ON THURSDAY NIGHT. BEST CHANCE FOR SHRA/ISOLD TSRA WILL BE OVR LK
SUPERIOR DUE TO H85 TEMP ADVECTION/WEAK LOW-LEVEL JET AND SOME
LOW-LEVEL FRONTAL CONVERGENCE. TEMPS WILL BE ON THE MILD SIDE
AGAIN WITH SOUTH WINDS/WARM AIR ADVECTION AHEAD OF FRONT. COLD
FRONT WORKS ACROSS UPR MICHIGAN ON FRIDAY...SO WILL KEEP WITH
SOME LOWER CHANCE POPS. COOLING BEGINS ON FRIDAY...ESPECIALLY NEAR
LK SUPERIOR. INLAND...TEMPS MAY END UP ONLY A COUPLE DEGREES COOLER
THAN THURSDAY.
STRONG DRYING BEHIND FRONT FOR FRIDAY NIGHT AND SATURDAY. JUST SOME
SCT CU SHOULD DEVELOP DURING PEAK HEATING ON SATURDAY. H85 TEMPS
ONLY UP TO +6C WITH STRONGER ONSHORE FLOW WILL LEAD TO A COOL DAY
BY AUGUST STANDARDS WITH READINGS IN THE UPPER 50S/NEAR 60 ALONG LK
SUPERIOR AND MAYBE REACHING 70 DEGREES IN THE FAR SOUTH CENTRAL NEAR
MNM. 60S ELSEWHERE...WHICH IS AT LEAST 10 DEGREES BLO NORMAL.
NOT MUCH IN WAY OF CHANGES TO REST OF CONSENSUS GRIDS FOR EXTENDED.
SLIGHT CHANCE POPS FOR SUNDAY...THOUGH THESE ARE BIASED BY A LATEST
GFS WHICH TRENDED MUCH WETTER FOR PARTS OF CWA COMPARED TO PREVIOUS
RUNS. ECMWF INDICATES SMALL CHANCES OF INSTABILITY SHRA/TSRA AS
ANOTHER STRONGER WAVE OR TWO /CURRENTLY WITHIN THE LARGER TROUGH FM
ALASKA TO THE NORTH POLE/ DROPS ACROSS UPPER LAKES. POCKET OF STEEPER
MID-LEVEL LAPSE RATES WOULD JUSTIFY AT LEAST A MENTION OF TSRA DURING
PEAK HEATING OF SUNDAY AFTN LINGERING INTO SUN EVENING. SIMILAR SETUP
FOR MONDAY THOUGH BY THAT TIME BETTER FORCING IS SLIDING EAST AND
SOUTH OF LK SUPERIOR REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 131 AM EDT TUE AUG 6 2013
ABUNDANT LOW LEVEL MOISTURE WILL REMAIN IN PLACE OVERNIGHT AS WEAK
SRLY FLOW CONTINUES. EXPECT IFR/LIFR CIGS AT SAW/CMX TO PERSIST AND
ONLY GRADUALLY IMPROVE TODAY AS WRLY FLOW BEHIND A SFC TROUGH BRINGS
IN DRIER AIR. CIGS ARE EXPECTED TO ALSO DROP INTO THE IFR RANGE AT
IWD PER GUIDANCE AND MDL LOW LEVEL MOISTURE FCST...ALTHOUGH
CONFIDENCE IS LOWER GIVEN MAINLY VFR/MVFR UPSTREAM CONDITIONS OVER NW
WI. ANY LEFTOVER LOWER CIGS SHOULD LIFT TO MVFR BY MID/LATE MORNING
AND TO VFR IN THE AFTERNOON. CIGS/VIS IS EXPECTED TO DROP AGAIN BY
EVENING AS SHOWERS MOVE IN AHEAD OF THE NEXT TROUGH. SOME THUNDER
MAY ALSO BE POSSIBLE BUT PROB/CONFIDENCE WAS LOW ENOUGH TO LEAVE OUT
MENTION.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 548 AM EDT TUE AUG 6 2013
LIGHT WINDS THROUGH MUCH OF TONIGHT THEN WINDS WILL KICK UP AS COLD
FRONT CROSSES LK SUPERIOR LATE TONIGHT THROUGH WEDNESDAY MORNING. NW
WINDS BEHIND COLD FRONT MAY REACH 20-25 KTS IN GUSTS. SHOWERS AND
STORMS LIKELY WITH THE FRONTAL PASSAGE. SHIP REPORTS INDICATE FOG
HAS FORMED OVERNIGHT WITH ARRIVAL OF MOIST AIRMASS. EXPECT THE FOG
TO CONTINUE UNTIL WEDNESDAY AFTERNOON WHEN DRIER AIR SCOURS OUT THE
FOG. WINDS DIMINISH TO LESS THAN 20 KTS WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT WITH HIGH PRESSURE OVERHEAD. STRONGER W-NW WINDS
POSSIBLE FRIDAY AND FRIDAY NIGHT AS ANOTHER COLD FRONT CROSSES
LAKE SUPERIOR FROM NORTH TO SOUTH. GUSTS COULD REACH OVER 25 KTS.
WINDS DIMINISH TO LESS THAN 20 KTS FOR REST OF WEEKEND WITH WEAKER
PRESSURE GRADIENT BY THAT TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
330 AM EDT TUE AUG 6 2013
.SYNOPSIS...
ISSUED AT 330 AM EDT TUE AUG 6 2013
IT WILL BE WARMER AND MORE HUMID TODAY WITH A FEW SHOWERS AND
THUNDERSTORMS. A COLD FRONT WILL BRING A BETTER CHANCE FOR SHOWERS
AND STORMS VERY LATE TONIGHT THROUGH WEDNESDAY. FAIR WEATHER WITH
SEASONABLE TEMPERATURES WILL RETURN LATE THIS WEEK.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON)
ISSUED AT 330 AM EDT TUE AUG 6 2013
SOUTHERLY FLOW WILL RESULT IN WARMER AND MORE HUMID WEATHER TODAY
WITH SUFFICIENT INSTABILITY FOR SCATTERED SHOWERS AND PERHAPS A FEW
STORMS TO DEVELOP THROUGH THE DAY. MAINTAINED ONLY LOW POPS SINCE
THERE IS A LACK OF A FOCUSING MECHANISM FOR CONVECTIVE INITIATION TO
OCCUR.
THE COLD FRONT WILL BRING A MUCH BETTER CHANCE FOR RAIN AND STORMS
VERY LATE TONIGHT THROUGH WEDNESDAY. THE BEST CHANCE FOR STRONGER
STORMS SHOULD COME WEDNESDAY AFTERNOON BUT THIS WILL BE LARGELY
CONTINGENT ON EXTENT OF CLOUD COVER AND INSTABILITY. MOISTURE IS
SUFFICIENT BUT SEVERE WX SEEMS UNLIKELY GIVEN LACK OF STRONGER
INSTABILITY.
DRY WX WITH SEASONABLE TEMPS WILL RETURN BEHIND THAT FRONT WEDNESDAY
NIGHT THROUGH THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 330 AM EDT TUE AUG 6 2013
IN GENERAL THE LONG TERM PERIOD LOOKS RELATIVELY QUIET WITH
TEMPERATURES CONTINUING TO AVERAGE A FEW DEGREES BELOW NORMAL.
PERSISTENT TROUGHING OVER EASTERN CANADA LOOKS TO STAY PUT WHICH
KEEPS A PREDOMINATELY NORTHWEST FLOW ALOFT IN TACT OVER THE GREAT
LAKES REGION.
AS THE CLOSED UPPER LOW CURRENTLY NEAR WESTERN HUDSON BAY DROPS
SSW... OUR FLOW ALOFT ACTUALLY GOES TEMPORARILY SOUTHWESTERLY ON
THURSDAY NIGHT INTO FRIDAY. AN UPPER LEVEL JET STREAK OF 100-120 KTS
PROGGED ON THE SOUTHEAST SIDE OF THE UPPER LOW ACROSS LAKE SUPERIOR
CREATES RIGHT ENTRANCE REGION DYNAMICS OVER SRN LWR MI. THIS MAY
HELP CREATE A RAIN SHOWER POTENTIAL ON THE NORTH SIDE OF THE STALLED
FRONTAL BOUNDARY TO OUR SOUTH. FOR THIS REASON WILL CARRY A SLIGHT
CHANCE OF RAIN SHOWERS THURSDAY NIGHT AND FRIDAY.
THE ONTARIO UPPER LOW LIFTS NORTHEAST INTO QUEBEC OVER THE
WEEKEND... SO WOULD NOT EXPECT MUCH OF A COLD AIR INTRUSION FROM THE
NORTH. RATHER... THE ZONAL FLOW ALOFT AND RIDGING AT THE SURFACE
SHOULD LEAD TO PLEASANT TEMPERATURES/HUMIDITIES OVER THE COMING
WEEKEND ALONG WITH DRY WEATHER. WILL REMAIN OPTIMISTIC WITH THE SKY
COVER FORECAST... BUT SUSPECT THAT INTERVALS OF THICKER MID/HIGH
CLOUDINESS WITHIN THE FAST ZONAL FLOW ALOFT MAY IMPACT THE AREA FROM
TIME TO TIME.
A SHORTWAVE DROPPING DOWN FROM THE NORTHWEST ON SUNDAY NIGHT AND
MONDAY COULD PRODUCE A FEW SHOWERS... BUT TIMING OF THIS FEATURE IS
TOUGH THAT FAR OUT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1152 PM EDT MON AUG 5 2013
AS I WAS THINKING AT 6 PM... THE LOW CLOUDS WILL COME IN FROM
WISCONSIN OVERNIGHT BRINGING IFR CIGS ACROSS THE AREA THAT WILL
NOT LIFT UNTIL LATE MORNING OR EARLY AFTERNOON TO TUESDAY.
THE REAL QUESTION IS WILL THERE BE SHOWERS OVERNIGHT... ENOUGH TO
LOWER THE VISIBILITIES THAT IS? GIVEN THE WATER VAPOR IMAGE LOOPS
SHOWING SO MUCH MID-LEVEL DRY AIR.... AND SEEING RAP AND NAM 00Z
MODEL RUN SOUNDINGS SHOWING SO MUCH DRY AIR ABOVE 700 MB THROUGH
THE NIGHT... EVEN SOUTH OF INTERSTATE 94... IT IS HARD TO IMAGE
ANYTHING TO SIGNIFICANT DEVELOPING. WHAT EVER DOES HAPPEN.. ARE
MORE LIKELY SOUTH OF INTERSTATE 96... SINCE THAT AREA IS CLOSER
THE TO BETTER MOISTURE AND BETTER LOW LEVEL INFLOW. I FEATURES
SHOWERS OVER THE SOUTHERN TAF SITES ONLY ON THE 06Z TAF SET.
&&
.MARINE...
ISSUED AT 330 AM EDT TUE AUG 6 2013
WAVE HEIGHTS MAINLY IN THE 1 TO 3 FOOT RANGE ARE EXPECTED TODAY IN
WARM AIR ADVECTION SOUTHERLY FLOW. WINDS WILL STRENGTHEN A BIT IN
ADVANCE OF THE COLD FRONT TONIGHT THAT SHOULD BUILD WAVES UP TO
AROUND 2 TO 4 FEET NORTH OF MUSKEGON. AFTER FROPA WEDNESDAY WAVES
WILL INCREASE IN NORTHERLY FLOW COOL AIR ADVECTION AND SMALL CRAFT
ADVISORIES AND BEACH HAZARDS STATEMENTS MAY BE NEEDED.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT TUE AUG 6 2013
ANY RAINFALL TODAY WILL BE RATHER LIGHT BUT SOME STEADIER RAIN AND
STORMS SHOULD ARRIVE LATE TONIGHT THROUGH WEDNESDAY WITH BASIN AVG
QPF AMOUNTS OF AT LEAST A QUARTER TO HALF INCH POSSIBLE WITH LOCALLY
HIGHER AMOUNTS. HOWEVER GIVEN ANTECEDENT LOW RIVER FLOWS WE DO NOT
EXPECT TO HAVE ANY MAJOR HYDRO ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...MEADE
AVIATION...WDM
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
349 AM CDT Tue Aug 6 2013
...SERIOUS FLASH FLOODING SITUATION UNFOLDING ACROSS PORTIONS OF
TEXAS AND PULASKI COUNTIES...
.SHORT TERM...(Today and Tonight)
ISSUED AT 349 AM CDT TUE AUG 6 2013
Very serious flooding situation unfolding across the area this
morning. A band of thunderstorms producing heavy rainfall has set
of up from roughly the Lake of the Ozark area southeastward
through portions of Laclede/Pulaski counties and into the northern
half of Texas county. Radar estimates vary a bit, but given
rainfall rate observations from the past several nights, as much
as 8" of rain has fallen in spots.
This band of rainfall will be the primary concern this morning. A
decaying line of storms entering from the west has produced a
large swath of moderate rain. Rainfall amounts are more modest
with a general half inch to one inch of rainfall over a longer
duration, with embedded pockets of up to two inches of rainfall.
The biggest concern for this morning is that band of torrential
rainfall from central Missouri into the eastern Ozarks and the
extreme flooding risk. Looking at the HRRR and other short range
models, this band of rainfall will not move much through day
break. With hourly rainfall rates between one and two inches, a
bad situation will only get worse.
Rain will gradually end from west to east during the mid to late
morning hours. Like yesterday some clearing is expected and a warm
and humid afternoon is in store. Instability will quickly increase
during the afternoon and additional isolated to widely scattered
thunderstorms will be possible across the entire area. There will
be a limited risk for severe with this activity, with hail to the
size of quarters and localized damaging wind gusts. This activity
will likely persist into the evening in a widely scattered
fashion. Then attention will turn to a complex of thunderstorms
develop to our north/northwest. This will approach the area from
the northwest overnight tonight. In addition, much like the past
few nights, will need to watch for low level jet interaction with
any lingering boundaries. This activity will be possible just
about anywhere across the outlook area. The airmass remains
extremely moist, and flash flooding will once again be a major
concern.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 349 AM CDT TUE AUG 6 2013
The forecast for midweek into early next week remains complex and
concerning. Northwest flow aloft will keep our region in the
atmospheric battleground, and multiple rounds of showers and
thunderstorms remain possible. There is moderate confidence in
another round of heavy rainfall Wednesday night into Thursday. As
a result, the Flash Flood Watch will be extended into Thursday
morning.
The medium range models do offer a glimmer of hope for the weekend
and the pattern briefly deamplifies and the atmospheric
battleground shifts just to the west. Tough to get to confident in
this solution given the persistent upper level pattern that has
been in place. One can certainly hope, though.
The bottom line is that more rounds of rain will be possible.
Temperatures will be at or below average (depending on cloud
coverage and rain).
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
ISSUED AT 815 PM CDT MON AUG 5 2013
Pilots can expect additional storms to move into the region
overnight bringing areas of MVFR conditions and the potential of
strong thunderstorm winds. IFR conditions will be possible in the
heavier rainfall. Improving flight conditions will return by
Tuesday afternoon.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH through Thursday morning FOR MOZ055>058-
066>071-077>083-088>098-101>106.
KS...FLASH FLOOD WATCH through Thursday morning FOR KSZ073-097-101.
&&
$$
SHORT TERM...Gagan
LONG TERM...Gagan
AVIATION...Foster
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
311 AM CDT Tue Aug 6 2013
.SHORT TERM...(Today through Wednesday)
Issued at 307 AM CDT TUE AUG 6 2013
Large MCS continues to interact with synoptic boundary arcing from
west central Missouri southeast through the Ozarks. Based on 00Z
soundings, convective outflow boundary should be more than sufficient
forcing to easily overturn the entire warm sector air mass as well as
the region through about 50 miles north. This sharp delineation has
been well handled by the HRRR and NSSL WRF runs, and takes the
northern extent of the thunderstorms to roughly the MO river from
Kansas City metro eastward. Thunderstorm cloud tops have continued
to be in the -75 to -80C range with prolific lightning counts. This
would suggest that despite the rich boundary layer moisture, rainfall
efficiency is not as high as it could be. Nonetheless, 1-2"/hr rates
are almost certain in the heavier cells, and there may be some
tendency for slower storm movement/propagation where the outflow
boundary becomes W-E oriented along the nrn edge of the convection.
80-100% POPs generally carried along and south of the MO river
(slightly more NW- SE oriented) with a rapid decrease further north.
Given the short term setup, while we definitely need the rain around
Kansas City, mesoscale influences suggest this is also the most
likely region for flooding through the next 3-4 hours if conceptual
evolution materializes.
Elsewhere, areas of light fog are expected along the periphery of the
MCS cloud shield where subsidence will work in concert with more
efficient boundary layer cooling and high antecedent moisture
content.
MCS (if not MCC designated) should gradually exit the CWA to the
southeast this morning as the low level jet veers, with convective
debris cirrus lingering through the morning. Like yesterday, most
aggressive warming will occur during the afternoon hours. Given the
very stagnant air mass in place, will introduce haze into the
forecast, coupling with otherwise very sultry conditions expected as
dewpoints climb into the middle 70s. Other than a rogue pulse
thunderstorm or two during the afternoon along a residual boundary,
expect the region to be fairly quiet between 15-00Z.
By evening, a disturbance currently producing active deep convection
over SW South Dakota will reach far NW MO. Despite model variances,
there appears to be an overall suggestion that at least scattered
thunderstorms will develop and/or move into NW MO early this evening,
possibly growing upscale overnight as this activity moves southeast.
SPC highlights the area with a broad slight risk overnight for wind
damage potential. Given some modest increase/linearity to the
700-500mb flow, certainly cannot rule out some storm organization.
This system should also clear the region by late morning, leaving a
hazy, warm and very humid day again on Wednesday.
.LONG TERM...(Thursday through Monday)
Issued at 307 AM CDT TUE AUG 6 2013
Remnant energy lifting northward out of the Baja California
Peninsula and into the Central Plains on Thursday will provide a
reasonable chance for fairly widespread rains across the lower
Missouri river valley. By Thursday morning ECMWF/GFS both suggest
increased troughing over the central Rockies, allowing for southwest
flow to move into the Plains. Strong warm advection ahead of this
wave of energy may be strong enough to force baroclinic zone which
has been stuck to the south of the CWA northward during the day. As
this upper wave ejects eastward Thursday night into Friday, fairly
pronounced mid-level lift provided by PVA and an enhanced upper jet
streak should keep PoPs high overnight as several rounds of showers
and thunderstorms will be possible.
High pressure is expected to sink southward into the central US on
Friday, leading to dry conditions for the first half of the weekend.
Increased troughing off the West Coast combined with fairly
progressive zonal flow over the Nation`s midsection will lead to
lower forecast confidence by early next week. Several waves of
energy may again eject eastward out of this trough, but timing of
these features remains too problematic to target any one time period
for higher PoPs.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 1045 PM CDT MON AUG 5 2013
Cluster of storms across southeast Kansas will continue to move east
southeast through the overnight hours. Bulk of the activity should
pass south of Kansas City, so only include VCTS in the KC terminals
for the early morning hours. Otherwise, thoughts are that ceilings
will stay in the VFR range unless a thunderstorm directly effects a
terminal, which will have to be handled with an amendment.
Otherwise, expect winds to back around to the south by the early
afternoon hours.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Bookbinder
LONG TERM...Dux
AVIATION...Cutter
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1132 PM CDT MON AUG 5 2013
.UPDATE...
ISSUED AT 844 PM CDT MON AUG 5 2013
THUNDERSTORMS HAVE STAYED SOUTHWEST OF THE CWA THIS EVENING...
THOUGH DO EXPECT ADDITIONAL STORMS TO DEVELOP FROM EASTERN KANSAS
INTO SOUTHEAST MISSOURI OVERNIGHT. THESE STORMS WILL DEVELOP IN A
BAND OF LOW LEVEL MOISTURE CONVERGENCE ON THE BROAD NOSE OF A LOW
LEVEL JET. LATEST RUNS OF THE HRRR SUGGESTS THAT NORTHERN AND
EASTERN EDGE OF THUNDERSTORMS WILL MOVE INTO CENTRAL AND SOUTHEAST
MISSOURI TOWARD SUNRISE...WITH BEST COVERAGE ACROSS SOUTHEAST
MISSOURI INTO SOUTHERN ILLINOIS BETWEEN 10-15Z. HAVE ADJUSTED RAIN
CHANCES TO GO ALONG WITH THIS IDEA. OTHERWISE...GOING FORECAST
LOOKS GOOD AND ONLY MADE MINOR TWEAKS TO TEMPERATURE AND CLOUD
COVER TO MATCH WITH GOING TRENDS.
BRITT
&&
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 333 PM CDT MON AUG 5 2013
FRONTAL BOUNDARY TO THE SOUTH WILL SLOWLY RETREAT AND MOVE NORTHWARD
OVERNIGHT TONIGHT. ISOLATED TO SCATERRED CONVECTION HAS DEVELOPED
ALONG IT OVER THE PAST COUPLE OF HOURS ACROSS PORTIONS OF SW
MISSOURI. THINKING THAT THIS CONVECTION SHOULD WEAKEN AND DIE OUT
THIS EVENING WITH LOSS OF DAYLIGHT HEATING. TIED HIGHEST POPS
TONIGHT TO PORTIONS OF SOUTH CENTRAL AND SOUTHEAST MISSOURI WHICH
WILL BE IN CLOSER PROXIMITY TO AFOREMENTIONED FRONT. DID LOWER
POPS A BIT FROM PREVIOUS FORECAST AS CONVERGENCE ALONG FRONT IS
RATHER WEAK AND LOW LEVEL FORCING IS PROGGED TO BE NOT NEARLY AS
STRONG OR FOCUSED TONIGHT AS PREVIOUS FEW NIGHTS. ALONG AND NORTH
OF BOUNDARY LOW STRATUS...AND POSSIBLY FOG...TO AFFECT MUCH OF THE
REGION WHICH WILL HELP KEEP LOW TEMPERATURES UP IN THE UPPER 60S
TO LOW 70S. BOOSTED LOWS A DEGREE OR TWO ABOVE WARMER MAV
GUIDANCE DUE TO EXPECTED LOW CLOUD COVER OVERNIGHT TONIGHT.
GOSSELIN
.LONG TERM...(TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 333 PM CDT MON AUG 5 2013
WITH WAA/ISENTROPIC ASCENT STILL OVER OUR AREA TUESDAY MORNING
COUPLED WITH A FEW VORTICITY MAXIMA RIDING OVER A RIDGE TO OUR SW...
THE SHOWERS AND THUNDERSTORMS THAT DEVELOPS OVERNIGHT SHOULD
CONTINUE TO PROPAGATE INTO OUR S COUNTIES DURING THE
MORNING...WITH LIKELY POPS AS FAR N AS A COLUMBIA TO SPARTA LINE.
ELSEWHERE...WILL MAINTAIN CHANCE OF POPS THROUGHOUT THE DAY...AS
TONGUE OF WAA PERSISTS OVER OUR AREA COUPLED WITH A FEW WEAK
SHORTWAVES WITHIN THE GENERAL FLOW. BY TUESDAY NIGHT...EXPECTING
AN UPTICK IN CONVECTIVE ACTIVITY OVER THE N 2/3 OF THE CWA AS WAA
INTENSIFIES EVEN MORE AHEAD OF APPRROACHING SHORTWAVE AND
ASSOCIATED COLD FRONT.
ON WEDNESDAY THE COLD FRONT IS EXPECTED TO SWEEP ACROSS THE AREA.
SOME MODELS SUGGEST THAT THE IMPACTS OF THE OVERNIGHT CONVECTION MAY
INHIBIT ADDITIONAL DEVELOPMENT OF CONVECTION ALONG THE FRONT DURING
THE DAY. HOWEVER...HAVE NOT MADE ANY MAJOR CHANGES TO CURRENT POPS ATTM.
12Z GFS REBOUNDS THE FRONTAL BOUNDARY AS A WARM FRONT ACROSS
OUR AREA LATE WEDNESDAY INTO THURSDAY MORNING IN RESPONSE TO A
DEEPENING SHORTWAVE TO THE WEST...WHILE MANY OF THE OTHER 12Z
SOLUTIONS ALLOW THE FRONTAL BOUNDARY TO SETTLE INTO N ARKANSAS.
WHILE THIS WILL IMPACT TEMPS...ALL SOLUTIONS POINT TO ACTIVE
BAROCLINIC ZONE REMAINING OVER S MISSOURI AND S ILLINOIS. THEREFORE
HAVE MAINTAINED LIKELY POPS OVER SOUTHERN SECTIONS OF THE CWA
THROUGH THURSDAY NIGHT WITH A CHANCE OF POPS ACROSS THE NORTH.
WITH TIME...MEDIUM RANGE SOLUTIONS DO INIDICATE THAT THE
BAROCLINIC ZONE WILL SAG SOUTH...WHICH IN TURN SHOULD ALLOW A SLOW
DECREASE IN POPS IN THE FRIDAY-SATURDAY TIME FRAME. HOWEVER...IT
APPEARS THAT TSRA THREAT WILL BE RETURNING BY THE START OF NEXT
WEEK AS LOW LEVEL WARM ADVECTION REDEVELOPS ACROSS THE REGION.
HUSTEDDE/TRUETT
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1105 PM CDT MON AUG 5 2013
RATHER COMPLEX WX SITUATION WITH ONE AREA OF MVFR CIGS MOVING SWD
OVER PORTIONS OF CENTRAL IL AND NERN MO...ANOTHER AREA OF IFR CIGS
MOVING NWD AND NEWD CURRENTLY ACROSS SRN AND SWRN IL AS WELL AS
SERN AND E CENTRAL MO. COMPLICATING MATTERS IS AREA OF TSRA
CURRENTLY OVER KS MOVING EWD WITH CI SHIELD OVER THE REGION.
UIN MAY COOL ENUF THRU THE NIGHT FOR AT LEAST MVFR FG TO DEVELOP
ALONG WITH AREA OF MVFR CIGS MOVING BACK NWD AS THE WRMFNT LIFTS
NWD TONIGHT. COU SHUD REMAIN VFR THRU MUCH OF THE NIGHT AS THICKER
CI CONTINUES TO MOVE OVER THE AREA AS TSRA COMPLEX APPROACHES.
BELIEVE THESE TSRA WILL REMAIN JUST S OF COU TERMINAL...BUT MAY
STILL SEE SPRINKLES OR A BRIEF PERIOD OF -RA. THESE TSRA ARE ALSO
EXPECTED TO REMAIN JUST S OF SUS/CPS TUES MORNING...BUT CAN NOT
RULE OUT DEVELOPMENT ALONG THE NRN FRINGES OF THE COMPLEX. UNTIL
THESE TSRA ARRIVE...BELIEVE IFR CIGS WILL REMAIN IN PLACE AS THE
WRMFNT SHUD REMAIN JUST S OF THE TERMINALS. THESE CIGS SHUD BE
SLOW TO RISE TUES.
KEPT MENTION OF VCSH TUES AFTERNOON WITH REDEVELOPMENT EXPECTED
ALONG THE FNT. BETTER CHANCES EXIST AT UIN TUES NIGHT NEAR THE END
OF THE TAF PERIOD AS A CDFNT MOVES S INTO THE REGION. WILL LEAVE
OUT FOR NOW.
SPECIFICS FOR KSTL...TSRA OVER KS WILL MOVE ESE TOWARD ERN MO
OVERNIGHT. EXPECT TSRA TO REMAIN S OF TERMINAL...BUT CAN NOT RULE
OUT DEVELOPMENT ALONG THE NRN FRINGES OF THIS COMPLEX. UNTIL
THEN...BELIEVE IFR CIGS WILL REMAIN IN PLACE AS THE WRMFNT
APPROACHES THE AREA. LOW CIGS SHUD BE SLOW TO LIFT TUES MORNING.
KEPT MENTION OF VCSH TUES AFTERNOON WHERE REDEVELOPMENT OF TSRA
ALONG THE FNT IS EXPECTED.
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1132 PM MDT MON AUG 5 2013
.AVIATION...
06Z TAF CYCLE
AN ACTIVE EVENING WINDING DOWN. HOWEVER...ISOLATED SHOWERS AND
STORMS STILL ONGOING OVER WESTERN AND NORTHERN NM. WILL CARRY AN
HOUR OR TWO TEMPO -SHRA AT KGUP...KFMN...KABQ AND KSAF. ALSO VCTS
AT KGUP AND KFMN. SHOULD BE VFR CONDITIONS THOUGH THROUGH AT LEAST
18Z TUE. NEXT CROP OF CONVECTION TUESDAY PM AND EVE MAY BE EVEN
MORE WIDESPREAD THAN TODAY AS AN UPPER LEVEL DISTURBANCE MOVES
NORTH ACROSS ERN AZ...DRAWING ADDITIONAL MOISTURE NORTH. WILL
CARRY VCTS ALL TERMINALS TUE PM EXCEPT KROW WHERE CHANCES WILL
BE LOWEST.
&&
.PREV DISCUSSION...244 PM MDT MON AUG 5 2013...
LESS ACTIVE TODAY THAN AT THIS TIME YESTERDAY. SHOWERS AND STORMS
WITH LOCALLY HVY RAIN ARE STILL DEVELOPING OVER THE NORTHERN AND
WESTERN HIGH TERRAIN AND EASTERN HIGH PLAINS. STORM MOTIONS ARE
FASTER AND MORE TO THE NORTHEAST. LAPS PARAMETERS STILL INDICATE
POTENTIAL FOR A FEW STRONG STORMS ARE FLASH FLOODING IS NOT OUT
OF THE QUESTION FOR ANY AREA. RUC GUIDANCE AGAIN SHOWS ACTIVITY
MERGING INTO THE RGV THIS VALLEY HOWEVER CONFIDENCE NOT AS HIGH
SINCE OTHER GUIDANCE MEMBERS KEEP ALL ACTIVITY FARTHER SOUTH AND
THERE IS A LESS THAN IMPRESSIVE CU FIELD OVER THE AREA ATTM. THE
INTERESTINGLY THERE IS A WELL DEFINED WAVE THAT HAS DEVELOPED IN
THE MONSOONAL PLUME HEADING NORTH INTO THE NM BOOTHEEL. FOR THIS
REASON HAVE KEPT A LARGER THAN TYPICAL AREA OF CHANCE POPS FOR
THE OVERNIGHT.
THE NEXT VERY WELL DEFINED WAVE IS POISED OVER THE BAJA REGION
AND THIS WILL MOVE NORTH THROUGH THE MONSOON PLUME TUESDAY. TOTAL
BLENDED PWAT VALUES PER CIRA IMAGERY WITH THIS WAVE ARE IN THE
2.25-2.50 RANGE. 12Z GFS INDICATES THE MAX THETA-E WAVE ASSOCIATED
WITH THIS SYSTEM WILL SLIDE OVER CENTRAL AND WESTERN NM NOW...
WHICH IS A LITTLE FARTHER EAST THAN PREVIOUS RUNS. STORM MOTIONS
WILL BE FASTER TO THE NE BUT FLASH FLOODING IS STILL A CONCERN.
THIS UPPER WAVE WILL GET CAUGHT UP IN INCREASING WESTERLY FLOW
OVER THE CENTRAL ROCKIES THEN NW FLOW OVER THE GREAT PLAINS.
A BACK DOOR FRONTAL BOUNDARY WILL BE FORCED SOUTHWARD INTO THE NE
PLAINS BEHIND THESE UPPER DYNAMICS. VERY MOIST UPSLOPE FLOW WILL
IMPACT THE SANGRES EASTWARD ACROSS THE PLAINS AND GIVEN LATEST
ROUNDS OF HEAVY RAINFALL IN THIS AREA...THE FLASH FLOOD THREAT
WILL BE QUITE HIGH. WEDNESDAY NIGHT EXPECTING TO SEE A LARGE RAIN
SHIELD SHIFTING SOUTHEAST OVER THE EAST...FOLLOWED BY A DRIER DAY
FOR THURSDAY. TEMPS WILL BE BELOW NORMAL THROUGH THE WHOLE PERIOD.
THE FRIDAY THROUGH MONDAY PERIOD LOOKS INTERESTING WITH ANOTHER
MONSOON BURST POSSIBLE DURING THIS TIME OVER CENTRAL AND WESTERN
NM. MODEL CONSISTENCY ON TIMING AND PLACEMENT IS NOT THE BEST
SO WILL KEEP VALUES JUST AT CLIMO OR BELOW FOR NOW.
GUYER
.FIRE WEATHER...
UPPER HIGH WILL REMAIN CENTERED OVER PORTIONS OF TEXAS AND THE LOWER
MISSISSIPPI VALLEY THROUGH TUESDAY. THE MONSOONAL MOISTURE PLUME
WILL REMAIN CENTERED OVER WESTERN AND CENTRAL NEW MEXICO DURING THIS
PERIOD. WETTING THUNDERSTORMS WILL BE EMBEDDED WITHIN THIS PLUME
WITH HIGHER HUMIDITY.
MODELS SHOWS A GRADUAL CHANGE IN THE MONSOON FLOW WEDNESDAY AND
THURSDAY AS A WEAK TROUGH SWINGS ACROSS THE SOUTHERN AND CENTRAL
ROCKIES. WEDNESDAY COULD BE QUITE DYNAMIC AS FAR AS AN EXPECTED
DRIER TREND ACROSS THE WEST AND WETTING THUNDERSTORMS CENTRAL AND
EASTERN AREAS. MODELS SHOW AN UPTICK IN THE UPPER FLOW SO THIS
SHOULD TRANSLATE INTO A LITTLE STRONGER SURFACE WIND VERSUS WHAT WE
HAVE HAD THE PAST SEVERAL DAYS. MIGHT BE A LITTLE LOW IN THE GRIDDED
WIND FORECAST SO WILL WATCH THE TREND IN THE MODELS. A BACK DOOR
COLD FRONT TIED TO A VIGOROUS LOW PRESSURE AREA SHOULD ADD TO THE
THUNDERSTORM FOCUS ACROSS THE NORTHEAST. IT APPEARS THAT HUMIDITY
VALUES LOWER THE MOST ACROSS THE SOUTHWEST HALF. THURSDAY LOOKS TO
BE DRIER BOTH HUMIDITY AND WETTING THUNDERSTORM WISE. WINDS ALSO
LOOK TO BE LIGHTER ON THURSDAY VERSUS WEDNESDAY.
BOTH THE ECMWF AND GFS WEATHER MODELS SHOW THE UPPER HIGH
REDEVELOPING OVER CENTRAL TEXAS ON FRIDAY. MONSOONAL MOISTURE WOULD
TRY TO FLOW BACK OVER THE AREA. AS OF RIGHT NOW...RESIDUAL OR
LEFTOVER MOISTURE SHOULD FOCUS WETTING THUNDERSTORM DEVELOPMENT OVER
THE NORTH CENTRAL MOUNTAINS AND PORTIONS OF THE NORTHEAST PLAINS.
THE PLUME OF MOISTURE SHOULD REINVIGORATE OVER WESTERN AND CENTRAL
NEW MEXICO DURING THE WEEKEND. HUMIDITY VALUES WOULD TREND UP. A
MONSOON BURST CONCENTRATING SIGNIFICANT MOISTURE AND STORMS WOULD BE
POSSIBLE DURING THIS PERIOD.
WEATHER MODELS TRY TO ELONGATE THE UPPER HIGH OVER PORTIONS OF NEW
MEXICO EARLY NEXT WEEK. RESIDUAL MOISTURE WOULD BE AROUND AND CAUGHT
WITHIN THIS UPPER HIGH ALTHOUGH STORMS WOULD BE MORE IN THE RECYCLE
MODE VERSUS A TRUE MONSOON BURST MODE. THUS THE WETTING RAIN
COVERAGE WOULD GRADUALLY DECLINE. WILL CONTINUE TO MONITOR THIS
TREND.
50
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO SLOWLY SHIFT FURTHER OFFSHORE THIS
MORNING...GIVING WAY TO A MOIST...SOUTHERLY LOW LEVEL RETURN FLOW
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 AM TUESDAY...
HIGH PRESSURE CENTERED OFF THE MID-ATLANTIC COAST THIS MORNING
EXTENDS SOUTHWEST OVER EASTERN NC/SC...WHILE A A RELATIVELY FAST
NORTHWESTERLY FLOW CONTINUES ALOFT. SOUTHEASTERLY RETURN FLOW
AROUND THE HIGH PRESSURE HAS BEEN CREATING SOME WEAK WARM ADVECTION
AND UPSLOPE FLOW...SUPPORTING THE DEVELOPMENT OF SCATTERED SHOWERS
OVER THE FOOTHILLS AND WESTERN PIEDMONT. HOWEVER... THE PRECIP HAS
STRUGGLED TO MOVE EAST ACROSS THE PIEDMONT ONCE IT MOVES OUT OF THE
BETTER LOW-LEVEL MOIST AXIS OVER WESTERN NC. RAP AND WATER VAPOR
IMAGERY SUGGEST A FEW WEAK DISTURBANCES ALOFT WILL DRIFT OVERHEAD
TODAY...WHICH MAY AID PRECIP IN MOVING FURTHER EAST ACROSS THE
PIEDMONT...BUT INSTABILITY WILL BE WEAK AND POPS WILL STILL BE
GRADUATED FROM CHANCE IN THE WEST TO SLIGHT CHANCE IN THE EAST.
SKIES WILL ALSO BE MORE CLOUDY OVER THE WESTERN CWA...WHERE FORECAST
SOUNDINGS SHOW A SOLID LAYER OF MOISTURE BETWEEN 850-700MB.
LOW-LEVEL THICKNESSES ARE ONLY SLIGHTLY HIGHER THAN THOSE OBSERVED
ON MONDAY OF AROUND 1400M. WITH PERIODS OF CLOUD COVER...HIGHS
SHOULD AGAIN BE IN THE LOW TO MID 80S.
TONIGHT...
SIMILAR TO THIS MORNING...SCATTERED SHOWER WILL BE POSSIBLE OVER THE
WESTERN CWA...WITH THE SHOWERS LIKELY TO WEAKEN AS THEY DRIFT EAST
INTO A MORE HOSTILE ENVIRONMENT AND SURFACE HIGH PRESSURE RIDGE.
LOWS IN THE UPPER 60S.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 245 AM TUESDAY...
WEDNESDAY AND WEDNESDAY NIGHT...
HIGH PRESSURE RIDGING ALONG THE CAROLINA COAST WILL WEAKEN WEDNESDAY
AS THE PARENT HIGH MOVES FURTHER OFF THE MID-ATLANTIC COAST AND COLD
FRONT MOVES THROUGH THE MIDWEST STATES. INSTABILITY...WHILE
SLIGHTLY GREATER THAN FORECAST FOR TODAY... WILL CONTINUE TO BE WEAK
OVER CENTRAL NC DESPITE RISING PRECIP WATER. WEAK WARM ADVECTION
AND UPSLOPE SHOULD STILL FAVOR SCATTERED SHOWERS AND ISOLATED STORMS
OVER THE WESTERN PIEDMONT. WHILE HIGHS WILL STILL BE BELOW
NORMAL...FORECAST SOUNDINGS SHOW A LITTLE LESS CLOUD COVER AND
BETTER MIXING...WHICH SHOULD SUPPORT HIGHS A COUPLE DEGREES WARMER
THAN TODAY...85-88. LOWS AROUND 70. -SMITH
FOR THURSDAY/THURSDAY NIGHT: THE CANADIAN VORTEX DRIFTS SLOWLY
EASTWARD TO CENTRAL ONTARIO THU/THU NIGHT AS WEAK MID LEVEL RIDGING
PASSES OVER NC... INSTIGATING SUBTLE WARMING ALOFT (500-300 MB) WITH
A VERY LIGHT WESTERLY MID LEVEL FLOW AND THE JET STREAM DISPLACED
WELL TO OUR NORTH ACROSS THE NRN GREAT LAKES... LARGE SCALE FORCED
ASCENT WILL BE LIMITED TO LOWER LEVEL MASS CONVERGENCE OVER THE NC
MOUNTAINS/FOOTHILLS INTO VA... IN THE LOW LEVEL MOIST CONVEYOR ZONE
WHERE PW VALUES WILL BE GREATEST (NEAR 2.0 INCHES). SREF
PROBABILITIES OF MEASURABLE RAIN REACH 50-70% OVER THE NW HALF OF
THE FORECAST AREA LATE THU MORNING THROUGH THE AFTERNOON...
CORRESPONDING TO MODEL-INDICATED AREAS OF ENHANCED LOW LEVEL
MOISTURE TRANSPORT ON THE PERIPHERY OF THE OFFSHORE SURFACE HIGH...
WITH PROBABILITIES OF 10% OR LOWER IN THE EAST WHERE FORECAST
SOUNDINGS SHOW SEVERAL LAYERS OF DRY AIR THROUGH THE COLUMN WITH
MINIMAL INSTABILITY. WILL KEEP CHANCE POPS ACROSS THE WRN AND FAR
NRN CWA... ON THE PERIPHERY OF THE RIDGE CORE... WITH ISOLATED POPS
OVER MUCH OF THE EAST. THE NAM HINTS AT POTENTIAL SEA-BREEZE
CONVECTION WORKING INTO THE EXTREME SE FORECAST AREA... SO WILL PUT
A SECONDARY POP MAX (BUT STILL JUST SMALL COVERAGE) HERE. HIGHS
86-90. MODELS AGREE ON ANY PRECIP SHUTTING OFF NEAR SUNSET... AND
EXPECT LARGELY DRY WEATHER OVERNIGHT BUT WITH MID CLOUDS MOVING IN
(BLOWOFF CLOUDS FROM MORE ORGANIZED/WIDESPREAD CONVECTION OVER
WV/KY/TN)... AND WE SHOULD SEE STRATUS/FOG FORMATION OVERNIGHT GIVEN
THE LIGHT SOUTH/SW FLOW AND RISING LOW LEVEL MOISTURE. LOWS 69-73.
FOR FRIDAY/FRIDAY NIGHT: THE CANADIAN VORTEX IS EXPECTED TO CONTINUE
ITS EASTWARD WOBBLE ACROSS ONTARIO TO THE TIP OF JAMES BAY DURING
THIS TIME FRAME. THE GFS HAS BEEN TRENDING SLOWER WITH THIS IN
RECENT RUNS... AND AS A RESULT IT NOW DELAYS THE ARRIVAL OF THE
GREATER COVERAGE OF CONVECTION WITHIN THE STREAM OF PREFRONTAL WARM
AIR ADVECTION... AND KEEPS THE FAR ERN CWA MAINLY DRY THROUGH FRI
NIGHT. THE GFS KEEPS THE UPPER LEVEL ANTICYCLONE CENTER OVER THE
CAROLINAS... AND WITH THE SWRLY UPPER JET CORE CROSSING THE GREAT
LAKES... THE BULK OF THE UPPER DIVERGENCE SKIRTS BY TO OUR NW AND
NORTH. THE SLIGHTLY FASTER ECMWF IS A BIT MORE EMPHATIC WITH
CONVECTION ACROSS CENTRAL NC ALONG THE LEE SURFACE TROUGH AS THE MID
LEVEL TROUGH AXIS APPROACHES... A SOLUTION THAT CANNOT BE DISCOUNTED
GIVEN THE EXPECTED MODERATE INSTABILITY (MLCAPE NEAR 1500 J/KG)...
SO WILL BRING IN CHANCE POPS AREAWIDE FRIDAY (MAINLY AFTERNOON INTO
EARLY EVENING)... DECREASING AFTER MID EVENING AS SUBSTANTIAL
FORCING FOR ASCENT CONTINUES TO BE LACKING... WHILE 850 MB FLOW
BECOMES MORE WESTERLY. FORECAST SOUNDINGS SUGGEST THAT THERE WILL BE
ENOUGH THIN SPOTS IN THE MID CLOUD COVERAGE TO FOSTER RADIATIONAL
COOLING AND ANOTHER ROUND OF STRATUS/FOG OVERNIGHT. HIGHS 87-91 WITH
THICKNESSES CLOSE TO NORMAL. LOWS 69-74. -GIH
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 305 AM TUESDAY...
STILL APPEARS LIKELY THAT WE`LL SEE THE BEST CHANCE OF
SHOWERS/STORMS DURING THIS FORECAST CYCLE ON SATURDAY... WITH LOWER
CHANCES LARGELY CONFINED TO SRN SECTIONS ON SUNDAY/MONDAY. THE
VORTEX WILL CROSS QUEBEC TO THE MARITIMES WHILE ADDITIONAL ENERGY TO
ITS NORTH DROPS INTO ITS WEST SIDE... ALLOWING THE LONGWAVE TROUGH
TO DEEPEN DOWN THROUGH THE GREAT LAKES/NORTHEAST/MIDATLANTIC...
EVENTUALLY LEADING TO STRENGTHENING WNW MID LEVEL FLOW OVER NC.
EXPECT A GOOD CHANCE OF SHOWERS/STORMS AREAWIDE SATURDAY AS THE
SURFACE FRONT APPROACHES... WITH A SOUTHWARD SUPPRESSION OF THESE
RAIN CHANCES SUNDAY/MONDAY AS THE FRONT DROPS SLOWLY THROUGH THE
AREA... PROPELLED BY THE STRENGTHENING WNW STEERING FLOW. GFS/ECMWF
THICKNESSES SUPPORT HIGHS NEAR TO JUST BELOW NORMAL... WITH LOWS A
BIT ABOVE NORMAL SAT NIGHT TRENDING TO JUST BELOW NORMAL SUNDAY
NIGHT. -GIH
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 145 AM TUESDAY...
SHOWERS CONTINUE TO DEVELOP WEST OVER THE WESTERN PIEDMONT AND
FOOTHILLS WHERE WEAK WARM ADVECTION AND UPSLOPE FLOW IS MORE
PROMINENT...BUT THE TREND HAS BEEN FOR THE SHOWERS TO DISSIPATE AS
THEY DRIFT EAST NEAR KINT/KGSO. HIGH PRESSURE OFF THE MID-ATLANTIC
COAST IS FORECAST TO REMAIN RELATIVELY STATIONARY TODAY...WITH
LITTLE CHANGE IN THE FLOW OVER CENTRAL NC. THUS...MOISTURE WILL
CONTINUE TO BE BEST OVER WESTERN NC AND SHOWERS OR STORMS WILL
STRUGGLE TO MOVE ACROSS THE PIEDMONT. FORECAST SOUNDINGS SHOW
CEILINGS IN THE 3000-5000 FT RANGE TODAY...ALTHOUGH MVFR CEILINGS
CERTAINLY WILL BE POSSIBLE AT KGSO AND KINT.
OUTLOOK...
EARLY MORNING STRATUS WILL BE A PROBLEM EACH MORNING THIS
WEEK AS A MOIST SOUTHERLY FLOW PERSISTS. THE CHANCE OF SHOWERS AND
STORMS WILL EXIST EACH DAY...PARTICULARLY OVER WESTERN NC. THE
WEATHER WILL BECOME MORE UNSETTLED BY THE END OF THE WEEK AS A COLD
FRONT MOVES INTO THE REGION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM..SMITH/HARTFIELD
LONG TERM...HARTFIELD
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
240 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO SLOWLY SHIFT FURTHER OFFSHORE THIS
MORNING...GIVING WAY TO A MOIST...SOUTHERLY LOW LEVEL RETURN FLOW
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 AM TUESDAY...
HIGH PRESSURE CENTERED OFF THE MID-ATLANTIC COAST THIS MORNING
EXTENDS SOUTHWEST OVER EASTERN NC/SC...WHILE A A RELATIVELY FAST
NORTHWESTERLY FLOW CONTINUES ALOFT. SOUTHEASTERLY RETURN FLOW
AROUND THE HIGH PRESSURE HAS BEEN CREATING SOME WEAK WARM ADVECTION
AND UPSLOPE FLOW...SUPPORTING THE DEVELOPMENT OF SCATTERED SHOWERS
OVER THE FOOTHILLS AND WESTERN PIEDMONT. HOWEVER... THE PRECIP HAS
STRUGGLED TO MOVE EAST ACROSS THE PIEDMONT ONCE IT MOVES OUT OF THE
BETTER LOW-LEVEL MOIST AXIS OVER WESTERN NC. RAP AND WATER VAPOR
IMAGERY SUGGEST A FEW WEAK DISTURBANCES ALOFT WILL DRIFT OVERHEAD
TODAY...WHICH MAY AID PRECIP IN MOVING FURTHER EAST ACROSS THE
PIEDMONT...BUT INSTABILITY WILL BE WEAK AND POPS WILL STILL BE
GRADUATED FROM CHANCE IN THE WEST TO SLIGHT CHANCE IN THE EAST.
SKIES WILL ALSO BE MORE CLOUDY OVER THE WESTERN CWA...WHERE FORECAST
SOUNDINGS SHOW A SOLID LAYER OF MOISTURE BETWEEN 850-700MB.
LOW-LEVEL THICKNESSES ARE ONLY SLIGHTLY HIGHER THAN THOSE OBSERVED
ON MONDAY OF AROUND 1400M. WITH PERIODS OF CLOUD COVER...HIGHS
SHOULD AGAIN BE IN THE LOW TO MID 80S.
TONIGHT...
SIMILAR TO THIS MORNING...SCATTERED SHOWER WILL BE POSSIBLE OVER THE
WESTERN CWA...WITH THE SHOWERS LIKELY TO WEAKEN AS THEY DRIFT EAST
INTO A MORE HOSTILE ENVIRONMENT AND SURFACE HIGH PRESSURE RIDGE.
LOWS IN THE UPPER 60S.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 245 AM TUESDAY...
WEDNESDAY AND WEDNESDAY NIGHT...
HIGH PRESSURE RIDGING ALONG THE CAROLINA COAST WILL WEAKEN WEDNESDAY
AS THE PARENT HIGH MOVES FURTHER OFF THE MID-ATLANTIC COAST AND COLD
FRONT MOVES THROUGH THE MIDWEST STATES. INSTABILITY...WHILE
SLIGHTLY GREATER THAN FORECAST FOR TODAY... WILL CONTINUE TO BE WEAK
OVER CENTRAL NC DESPITE RISING PRECIP WATER. WEAK WARM ADVECTION
AND UPSLOPE SHOULD STILL FAVOR SCATTERED SHOWERS AND ISOLATED STORMS
OVER THE WESTERN PIEDMONT. WHILE HIGHS WILL STILL BE BELOW
NORMAL...FORECAST SOUNDINGS SHOW A LITTLE LESS CLOUD COVER AND
BETTER MIXING...WHICH SHOULD SUPPORT HIGHS A COUPLE DEGREES WARMER
THAN TODAY...85-88. LOWS AROUND 70. -SMITH
FOR THURSDAY/THURSDAY NIGHT: THE CANADIAN VORTEX DRIFTS SLOWLY
EASTWARD TO CENTRAL ONTARIO THU/THU NIGHT AS WEAK MID LEVEL RIDGING
PASSES OVER NC... INSTIGATING SUBTLE WARMING ALOFT (500-300 MB) WITH
A VERY LIGHT WESTERLY MID LEVEL FLOW AND THE JET STREAM DISPLACED
WELL TO OUR NORTH ACROSS THE NRN GREAT LAKES... LARGE SCALE FORCED
ASCENT WILL BE LIMITED TO LOWER LEVEL MASS CONVERGENCE OVER THE NC
MOUNTAINS/FOOTHILLS INTO VA... IN THE LOW LEVEL MOIST CONVEYOR ZONE
WHERE PW VALUES WILL BE GREATEST (NEAR 2.0 INCHES). SREF
PROBABILITIES OF MEASURABLE RAIN REACH 50-70% OVER THE NW HALF OF
THE FORECAST AREA LATE THU MORNING THROUGH THE AFTERNOON...
CORRESPONDING TO MODEL-INDICATED AREAS OF ENHANCED LOW LEVEL
MOISTURE TRANSPORT ON THE PERIPHERY OF THE OFFSHORE SURFACE HIGH...
WITH PROBABILITIES OF 10% OR LOWER IN THE EAST WHERE FORECAST
SOUNDINGS SHOW SEVERAL LAYERS OF DRY AIR THROUGH THE COLUMN WITH
MINIMAL INSTABILITY. WILL KEEP CHANCE POPS ACROSS THE WRN AND FAR
NRN CWA... ON THE PERIPHERY OF THE RIDGE CORE... WITH ISOLATED POPS
OVER MUCH OF THE EAST. THE NAM HINTS AT POTENTIAL SEA-BREEZE
CONVECTION WORKING INTO THE EXTREME SE FORECAST AREA... SO WILL PUT
A SECONDARY POP MAX (BUT STILL JUST SMALL COVERAGE) HERE. HIGHS
86-90. MODELS AGREE ON ANY PRECIP SHUTTING OFF NEAR SUNSET... AND
EXPECT LARGELY DRY WEATHER OVERNIGHT BUT WITH MID CLOUDS MOVING IN
(BLOWOFF CLOUDS FROM MORE ORGANIZED/WIDESPREAD CONVECTION OVER
WV/KY/TN)... AND WE SHOULD SEE STRATUS/FOG FORMATION OVERNIGHT GIVEN
THE LIGHT SOUTH/SW FLOW AND RISING LOW LEVEL MOISTURE. LOWS 69-73.
FOR FRIDAY/FRIDAY NIGHT: THE CANADIAN VORTEX IS EXPECTED TO CONTINUE
ITS EASTWARD WOBBLE ACROSS ONTARIO TO THE TIP OF JAMES BAY DURING
THIS TIME FRAME. THE GFS HAS BEEN TRENDING SLOWER WITH THIS IN
RECENT RUNS... AND AS A RESULT IT NOW DELAYS THE ARRIVAL OF THE
GREATER COVERAGE OF CONVECTION WITHIN THE STREAM OF PREFRONTAL WARM
AIR ADVECTION... AND KEEPS THE FAR ERN CWA MAINLY DRY THROUGH FRI
NIGHT. THE GFS KEEPS THE UPPER LEVEL ANTICYCLONE CENTER OVER THE
CAROLINAS... AND WITH THE SWRLY UPPER JET CORE CROSSING THE GREAT
LAKES... THE BULK OF THE UPPER DIVERGENCE SKIRTS BY TO OUR NW AND
NORTH. THE SLIGHTLY FASTER ECMWF IS A BIT MORE EMPHATIC WITH
CONVECTION ACROSS CENTRAL NC ALONG THE LEE SURFACE TROUGH AS THE MID
LEVEL TROUGH AXIS APPROACHES... A SOLUTION THAT CANNOT BE DISCOUNTED
GIVEN THE EXPECTED MODERATE INSTABILITY (MLCAPE NEAR 1500 J/KG)...
SO WILL BRING IN CHANCE POPS AREAWIDE FRIDAY (MAINLY AFTERNOON INTO
EARLY EVENING)... DECREASING AFTER MID EVENING AS SUBSTANTIAL
FORCING FOR ASCENT CONTINUES TO BE LACKING... WHILE 850 MB FLOW
BECOMES MORE WESTERLY. FORECAST SOUNDINGS SUGGEST THAT THERE WILL BE
ENOUGH THIN SPOTS IN THE MID CLOUD COVERAGE TO FOSTER RADIATIONAL
COOLING AND ANOTHER ROUND OF STRATUS/FOG OVERNIGHT. HIGHS 87-91 WITH
THICKNESSES CLOSE TO NORMAL. LOWS 69-74. -GIH
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 318 PM MONDAY...
SATURDAY....SUB TROPICAL RIDGE PROJECTED TO EXPAND/STRENGTHEN
WEST-TO-EAST ACROSS THE LOWER MS VALLEY AND SE U.S. THIS WILL PLACE
CENTRAL NC ON THE PERIPHERY OF THIS WEATHER SYSTEM. WEAK
PERTURBATIONS TRAVERSING EWD COUPLED WITH AVAILABLE MOISTURE AND
INSTABILITY SUGGEST A THREAT FOR SCATTERED SHOWERS AND STORMS EACH
DAY...MORE SO ON SATURDAY AFTERNOON AS A S/W IN THE NORTHERN STREAM
PROPELS A SFC FRONT SWD TOWARD CENTRAL NC. PLAN TO HAVE HIGH CHANCE
POPS MOST LOCATIONS LATE SATURDAY-SATURDAY NIGHT.
SUNDAY INTO MONDAY....LATEST GFS HAS TRENDED TOWARD THE MORE
PROGRESSIVE ECMWF WHICH PUSHES THE SFC COLD FRONT SWD ACROSS CENTRAL
NC SUNDAY...AND POSITIONED SOUTH OF THE REGION MONDAY. THIS SUGGEST
A DECREASING THREAT FOR SCATTERED SHOWERS AND STORMS. PLAN TO
MAINTAIN MENTION OF A SMALL CHANCE BOTH DAYS...SUNDAY TO ACCOUNT FOR
POSSIBLE MODEL TIMING ISSUES WITH THE FRONTAL PASSAGE...AND ON
MONDAY AS DEVELOPING NW FLOW ALOFT MAY PROVIDE AN AVENUE FOR
DISTURBANCES ROTATING AROUND A DEEP CLOSED UPPER LOW OVER THE
NORTHERN LAKES TO TRANSLATE INTO OUR REGION.
TEMPS THURSDAY THROUGH MONDAY DEPENDENT UPON EXTENT OF CLOUD COVER
AND AREAL COVERAGE OF CONVECTION. EXPECT AFTERNOON TEMPS TO AVERAGE
A COUPLE OF DEGREES BELOW NORMAL WHILE OVERNIGHT TEMPS WILL BE 3-5
DEGREES ABOVE NORMAL.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 145 AM TUESDAY...
SHOWERS CONTINUE TO DEVELOP WEST OVER THE WESTERN PIEDMONT AND
FOOTHILLS WHERE WEAK WARM ADVECTION AND UPSLOPE FLOW IS MORE
PROMINENT...BUT THE TREND HAS BEEN FOR THE SHOWERS TO DISSIPATE AS
THEY DRIFT EAST NEAR KINT/KGSO. HIGH PRESSURE OFF THE MID-ATLANTIC
COAST IS FORECAST TO REMAIN RELATIVELY STATIONARY TODAY...WITH
LITTLE CHANGE IN THE FLOW OVER CENTRAL NC. THUS...MOISTURE WILL
CONTINUE TO BE BEST OVER WESTERN NC AND SHOWERS OR STORMS WILL
STRUGGLE TO MOVE ACROSS THE PIEDMONT. FORECAST SOUNDINGS SHOW
CEILINGS IN THE 3000-5000 FT RANGE TODAY...ALTHOUGH MVFR CEILINGS
CERTAINLY WILL BE POSSIBLE AT KGSO AND KINT.
OUTLOOK...
EARLY MORNING STRATUS WILL BE A PROBLEM EACH MORNING THIS
WEEK AS A MOIST SOUTHERLY FLOW PERSISTS. THE CHANCE OF SHOWERS AND
STORMS WILL EXIST EACH DAY...PARTICULARLY OVER WESTERN NC. THE
WEATHER WILL BECOME MORE UNSETTLED BY THE END OF THE WEEK AS A COLD
FRONT MOVES INTO THE REGION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM..SMITH/HARTFIELD
LONG TERM...WSS
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
222 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO SLOWLY SHIFT FURTHER OFFSHORE
TONIGHT. A MOIST SOUTHERLY LOW LEVEL RETURN FLOW WILL PREVAIL
THROUGH MID TO LATE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 915 PM MONDAY...
TONIGHT:
SURFACE HIGH PRESSURE HAS SHIFTED JUST OFF THE SOUTHERN MID-ATLANTIC
COAST THIS EVENING... WHILE THE MID/UPPER LEVEL FLOW ALOFT CONTINUES
TO BE OUT OF THE NORTHWEST. THIS HAS RESULTED IN A LIGHT
SOUTH/SOUTHEASTERLY SURFACE/LOW LEVEL RETURN FLOW UP AND INTO THE
HIGHER TERRAIN ALONG WITH WEAK PERTURBATION MOVING THROUGH THE
NORTHWEST FLOW ALOFT... WHICH HAS ALLOWED SOME SHOWERS TO DEVELOP IN
THE HIGHER TERRAIN. THESE SHOWERS (AND PERHAPS A THUNDERSTORM OR
TWO) HAVE HAD A HARD TIME COMING OFF THE HIGHER TERRAIN AND INTO THE
PIEDMONT. HOWEVER... THE LATEST HRRR AND SOME OF THE OTHER HI-RES
GUIDANCE IS NOW SHOWING THIS ACTIVITY SLOWLY SHIFTING EASTWARD AND
INTO THE PIEDMONT LATER THIS EVENING INTO THE OVERNIGHT HOURS. GIVEN
THE RATHER WEAK INSTABILITY EXPECTED OVER OUR AREA... WE DO NOT
ANTICIPATE ANY SVR WEATHER FROM THIS ACTIVITY. HOWEVER... WE COULD
SEE A BRIEF HEAVY DOWNPOUR AND REDUCED VISIBILITY AS A SHOWER AND/OR
STORM MOVES ACROSS A GIVEN LOCATION. THE HIGHEST PROBABILITIES WILL
REMAIN ACROSS THE NORTH/NORTHWESTERN PIEDMONT THIS EVENING/TONIGHT.
THUS... WILL CONTINUE TO SHOW THE FAR NORTHWEST PIEDMONT WITH THE
HIGHEST POPS AFTER MIDNIGHT (CHANCE... 25-40 PERCENT) TO SLIGHT
CHANCE JUST WEST OF RALEIGH. GIVEN THIS EXPECT SKIES WILL GENERALLY
BE PARTLY TO MOSTLY CLOUDY/CLOUDY OVERNIGHT... WHICH WILL HELP TO
KEEP TEMPS UP A BIT TONIGHT... ALONG WITH THE INCREASE IN LOW LEVEL
MOISTURE. THUS... EXPECT LOWS TO RANGE FROM THE MID 60S EAST TO
UPPER 60S WEST. -BSD
TUESDAY:
EXPECT AN INCREASING POTENTIAL FOR SHOWER (THUNDERSTORM) ACTIVITY
TUESDAY MORNING (AFTERNOON) AS A SEASONABLY MOIST SOUTHERLY
LOW-LEVEL RETURN FLOW AIDS IN MARGINAL TO MODERATE DIURNAL
DESTABILIZATION IN THE PRESENCE OF WEAK LOW-LEVEL CONVERGENCE AND AN
INCREASED POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN NW FLOW
ALOFT. WILL INDICATE PRECIP CHANCES RANGING FROM 20-50%...HIGHEST IN
THE WESTERN PIEDMONT AND LOWEST IN THE COASTAL PLAIN WHERE LOW-LEVEL
MOISTURE /DIURNAL DESTABILIZATION/ IS EXPECTED TO BE MARGINAL. HIGHS
WILL BE SIMILAR TO TODAY AND PRIMARILY DEPEND ON CLOUD COVER...
RANGING FROM NEAR 80F IN THE N/NW PIEDMONT TO MID/UPPER 80S IN THE
SANDHILLS AND COASTAL PLAIN. -VINCENT
&&
.SHORT TERM /TUESDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 318 PM MONDAY / 220 AM TUESDAY...
TUESDAY NIGHT...APPROACH OF A WEAK MID-UPPER LEVEL DISTURBANCE
COUPLED WITH AN INCREASINGLY MOIST AIR MASS WILL SUPPORT THE
POTENTIAL FOR A FEW SHOWERS/ISOLATED THUNDER WELL INTO THE
NIGHT...MAINLY OVER THE NW PIEDMONT. INCREASING/THICKENING CLOUD
COVER AND A LIGHT SLY WIND WILL RESULT IN A FAIRLY UNIFORM TEMP
FIELD OVERNIGHT. MIN TEMPS UPPER 60S TO AROUND 70.
WEDNESDAY AND WEDNESDAY NIGHT...THE MID-UPPER LEVEL TROUGH TRANSLATE
SLOWLY EWD TOWARD AND ACROSS THE MID ATLANTIC AND CAROLINAS WED
AFTERNOON-EVENING. 12Z GFS NOT TOO IMPRESSIVE WITH ITS CONVECTIVE
PARAMETERS WED AFTERNOON-EVENING ...DEPICTING MARGINAL/SLIGHT
INSTABILITY AT BEST. STILL...FAVORED LOW LEVEL CONFLUENCE OVER THE
WESTERN PIEDMONT DURING PRIME HEATING SUPPORT HIGH CHANCE POP IN
THIS REGION....WITH POPS TAPERING TO SLIGHT CHANCE OVER THE SOUTHERN
COASTAL PLAINS AND SANDHILLS. MORE CLOUDS THAN SUN WILL LIMIT NORMAL
DIURNAL TEMP RISE IN THE WEST-NW WHERE MAX TEMPS EXPECTED TO BE
LOWER 80S. PARTIAL SUN OVER THE SE HALF SHOULD WARM TEMPS WELL INTO
THE 80S. CONSIDERABLE CLOUDINESS WEDNESDAY NIGHT WILL MAINTAIN HUMID
CONDITIONS. MIN TEMPS AROUND 70/LOWER 70S. -WSS
FOR THURSDAY/THURSDAY NIGHT: THE CANADIAN VORTEX DRIFTS SLOWLY
EASTWARD TO CENTRAL ONTARIO THU/THU NIGHT AS WEAK MID LEVEL RIDGING
PASSES OVER NC... INSTIGATING SUBTLE WARMING ALOFT (500-300 MB) WITH
A VERY LIGHT WESTERLY MID LEVEL FLOW AND THE JET STREAM DISPLACED
WELL TO OUR NORTH ACROSS THE NRN GREAT LAKES... LARGE SCALE FORCED
ASCENT WILL BE LIMITED TO LOWER LEVEL MASS CONVERGENCE OVER THE NC
MOUNTAINS/FOOTHILLS INTO VA... IN THE LOW LEVEL MOIST CONVEYOR ZONE
WHERE PW VALUES WILL BE GREATEST (NEAR 2.0 INCHES). SREF
PROBABILITIES OF MEASURABLE RAIN REACH 50-70% OVER THE NW HALF OF
THE FORECAST AREA LATE THU MORNING THROUGH THE AFTERNOON...
CORRESPONDING TO MODEL-INDICATED AREAS OF ENHANCED LOW LEVEL
MOISTURE TRANSPORT ON THE PERIPHERY OF THE OFFSHORE SURFACE HIGH...
WITH PROBABILITIES OF 10% OR LOWER IN THE EAST WHERE FORECAST
SOUNDINGS SHOW SEVERAL LAYERS OF DRY AIR THROUGH THE COLUMN WITH
MINIMAL INSTABILITY. WILL KEEP CHANCE POPS ACROSS THE WRN AND FAR
NRN CWA... ON THE PERIPHERY OF THE RIDGE CORE... WITH ISOLATED POPS
OVER MUCH OF THE EAST. THE NAM HINTS AT POTENTIAL SEA-BREEZE
CONVECTION WORKING INTO THE EXTREME SE FORECAST AREA... SO WILL PUT
A SECONDARY POP MAX (BUT STILL JUST SMALL COVERAGE) HERE. HIGHS
86-90. MODELS AGREE ON ANY PRECIP SHUTTING OFF NEAR SUNSET... AND
EXPECT LARGELY DRY WEATHER OVERNIGHT BUT WITH MID CLOUDS MOVING IN
(BLOWOFF CLOUDS FROM MORE ORGANIZED/WIDESPREAD CONVECTION OVER
WV/KY/TN)... AND WE SHOULD SEE STRATUS/FOG FORMATION OVERNIGHT GIVEN
THE LIGHT SOUTH/SW FLOW AND RISING LOW LEVEL MOISTURE. LOWS 69-73.
FOR FRIDAY/FRIDAY NIGHT: THE CANADIAN VORTEX IS EXPECTED TO CONTINUE
ITS EASTWARD WOBBLE ACROSS ONTARIO TO THE TIP OF JAMES BAY DURING
THIS TIME FRAME. THE GFS HAS BEEN TRENDING SLOWER WITH THIS IN
RECENT RUNS... AND AS A RESULT IT NOW DELAYS THE ARRIVAL OF THE
GREATER COVERAGE OF CONVECTION WITHIN THE STREAM OF PREFRONTAL WARM
AIR ADVECTION... AND KEEPS THE FAR ERN CWA MAINLY DRY THROUGH FRI
NIGHT. THE GFS KEEPS THE UPPER LEVEL ANTICYCLONE CENTER OVER THE
CAROLINAS... AND WITH THE SWRLY UPPER JET CORE CROSSING THE GREAT
LAKES... THE BULK OF THE UPPER DIVERGENCE SKIRTS BY TO OUR NW AND
NORTH. THE SLIGHTLY FASTER ECMWF IS A BIT MORE EMPHATIC WITH
CONVECTION ACROSS CENTRAL NC ALONG THE LEE SURFACE TROUGH AS THE MID
LEVEL TROUGH AXIS APPROACHES... A SOLUTION THAT CANNOT BE DISCOUNTED
GIVEN THE EXPECTED MODERATE INSTABILITY (MLCAPE NEAR 1500 J/KG)...
SO WILL BRING IN CHANCE POPS AREAWIDE FRIDAY (MAINLY AFTERNOON INTO
EARLY EVENING)... DECREASING AFTER MID EVENING AS SUBSTANTIAL
FORCING FOR ASCENT CONTINUES TO BE LACKING... WHILE 850 MB FLOW
BECOMES MORE WESTERLY. FORECAST SOUNDINGS SUGGEST THAT THERE WILL BE
ENOUGH THIN SPOTS IN THE MID CLOUD COVERAGE TO FOSTER RADIATIONAL
COOLING AND ANOTHER ROUND OF STRATUS/FOG OVERNIGHT. HIGHS 87-91 WITH
THICKNESSES CLOSE TO NORMAL. LOWS 69-74. -GIH
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 318 PM MONDAY...
SATURDAY....SUB TROPICAL RIDGE PROJECTED TO EXPAND/STRENGTHEN
WEST-TO-EAST ACROSS THE LOWER MS VALLEY AND SE U.S. THIS WILL PLACE
CENTRAL NC ON THE PERIPHERY OF THIS WEATHER SYSTEM. WEAK
PERTURBATIONS TRAVERSING EWD COUPLED WITH AVAILABLE MOISTURE AND
INSTABILITY SUGGEST A THREAT FOR SCATTERED SHOWERS AND STORMS EACH
DAY...MORE SO ON SATURDAY AFTERNOON AS A S/W IN THE NORTHERN STREAM
PROPELS A SFC FRONT SWD TOWARD CENTRAL NC. PLAN TO HAVE HIGH CHANCE
POPS MOST LOCATIONS LATE SATURDAY-SATURDAY NIGHT.
SUNDAY INTO MONDAY....LATEST GFS HAS TRENDED TOWARD THE MORE
PROGRESSIVE ECMWF WHICH PUSHES THE SFC COLD FRONT SWD ACROSS CENTRAL
NC SUNDAY...AND POSITIONED SOUTH OF THE REGION MONDAY. THIS SUGGEST
A DECREASING THREAT FOR SCATTERED SHOWERS AND STORMS. PLAN TO
MAINTAIN MENTION OF A SMALL CHANCE BOTH DAYS...SUNDAY TO ACCOUNT FOR
POSSIBLE MODEL TIMING ISSUES WITH THE FRONTAL PASSAGE...AND ON
MONDAY AS DEVELOPING NW FLOW ALOFT MAY PROVIDE AN AVENUE FOR
DISTURBANCES ROTATING AROUND A DEEP CLOSED UPPER LOW OVER THE
NORTHERN LAKES TO TRANSLATE INTO OUR REGION.
TEMPS THURSDAY THROUGH MONDAY DEPENDENT UPON EXTENT OF CLOUD COVER
AND AREAL COVERAGE OF CONVECTION. EXPECT AFTERNOON TEMPS TO AVERAGE
A COUPLE OF DEGREES BELOW NORMAL WHILE OVERNIGHT TEMPS WILL BE 3-5
DEGREES ABOVE NORMAL.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 145 AM TUESDAY...
SHOWERS CONTINUE TO DEVELOP WEST OVER THE WESTERN PIEDMONT AND
FOOTHILLS WHERE WEAK WARM ADVECTION AND UPSLOPE FLOW IS MORE
PROMINENT...BUT THE TREND HAS BEEN FOR THE SHOWERS TO DISSIPATE AS
THEY DRIFT EAST NEAR KINT/KGSO. HIGH PRESSURE OFF THE MID-ATLANTIC
COAST IS FORECAST TO REMAIN RELATIVELY STATIONARY TODAY...WITH
LITTLE CHANGE IN THE FLOW OVER CENTRAL NC. THUS...MOISTURE WILL
CONTINUE TO BE BEST OVER WESTERN NC AND SHOWERS OR STORMS WILL
STRUGGLE TO MOVE ACROSS THE PIEDMONT. FORECAST SOUNDINGS SHOW
CEILINGS IN THE 3000-5000 FT RANGE TODAY...ALTHOUGH MVFR CEILINGS
CERTAINLY WILL BE POSSIBLE AT KGSO AND KINT.
OUTLOOK...
EARLY MORNING STRATUS WILL BE A PROBLEM EACH MORNING THIS
WEEK AS A MOIST SOUTHERLY FLOW PERSISTS. THE CHANCE OF SHOWERS AND
STORMS WILL EXIST EACH DAY...PARTICULARLY OVER WESTERN NC. THE
WEATHER WILL BECOME MORE UNSETTLED BY THE END OF THE WEEK AS A COLD
FRONT MOVES INTO THE REGION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD
NEAR TERM...BSD/VINCENT
SHORT TERM..WSS/HARTFIELD
LONG TERM...WSS
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
145 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO SLOWLY SHIFT FURTHER OFFSHORE
TONIGHT. A MOIST SOUTHERLY LOW LEVEL RETURN FLOW WILL PREVAIL
THROUGH MID TO LATE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 915 PM MONDAY...
TONIGHT:
SURFACE HIGH PRESSURE HAS SHIFTED JUST OFF THE SOUTHERN MID-ATLANTIC
COAST THIS EVENING... WHILE THE MID/UPPER LEVEL FLOW ALOFT CONTINUES
TO BE OUT OF THE NORTHWEST. THIS HAS RESULTED IN A LIGHT
SOUTH/SOUTHEASTERLY SURFACE/LOW LEVEL RETURN FLOW UP AND INTO THE
HIGHER TERRAIN ALONG WITH WEAK PERTURBATION MOVING THROUGH THE
NORTHWEST FLOW ALOFT... WHICH HAS ALLOWED SOME SHOWERS TO DEVELOP IN
THE HIGHER TERRAIN. THESE SHOWERS (AND PERHAPS A THUNDERSTORM OR
TWO) HAVE HAD A HARD TIME COMING OFF THE HIGHER TERRAIN AND INTO THE
PIEDMONT. HOWEVER... THE LATEST HRRR AND SOME OF THE OTHER HI-RES
GUIDANCE IS NOW SHOWING THIS ACTIVITY SLOWLY SHIFTING EASTWARD AND
INTO THE PIEDMONT LATER THIS EVENING INTO THE OVERNIGHT HOURS. GIVEN
THE RATHER WEAK INSTABILITY EXPECTED OVER OUR AREA... WE DO NOT
ANTICIPATE ANY SVR WEATHER FROM THIS ACTIVITY. HOWEVER... WE COULD
SEE A BRIEF HEAVY DOWNPOUR AND REDUCED VISIBILITY AS A SHOWER AND/OR
STORM MOVES ACROSS A GIVEN LOCATION. THE HIGHEST PROBABILITIES WILL
REMAIN ACROSS THE NORTH/NORTHWESTERN PIEDMONT THIS EVENING/TONIGHT.
THUS... WILL CONTINUE TO SHOW THE FAR NORTHWEST PIEDMONT WITH THE
HIGHEST POPS AFTER MIDNIGHT (CHANCE... 25-40 PERCENT) TO SLIGHT
CHANCE JUST WEST OF RALEIGH. GIVEN THIS EXPECT SKIES WILL GENERALLY
BE PARTLY TO MOSTLY CLOUDY/CLOUDY OVERNIGHT... WHICH WILL HELP TO
KEEP TEMPS UP A BIT TONIGHT... ALONG WITH THE INCREASE IN LOW LEVEL
MOISTURE. THUS... EXPECT LOWS TO RANGE FROM THE MID 60S EAST TO
UPPER 60S WEST. -BSD
TUESDAY:
EXPECT AN INCREASING POTENTIAL FOR SHOWER (THUNDERSTORM) ACTIVITY
TUESDAY MORNING (AFTERNOON) AS A SEASONABLY MOIST SOUTHERLY
LOW-LEVEL RETURN FLOW AIDS IN MARGINAL TO MODERATE DIURNAL
DESTABILIZATION IN THE PRESENCE OF WEAK LOW-LEVEL CONVERGENCE AND AN
INCREASED POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN NW FLOW
ALOFT. WILL INDICATE PRECIP CHANCES RANGING FROM 20-50%...HIGHEST IN
THE WESTERN PIEDMONT AND LOWEST IN THE COASTAL PLAIN WHERE LOW-LEVEL
MOISTURE /DIURNAL DESTABILIZATION/ IS EXPECTED TO BE MARGINAL. HIGHS
WILL BE SIMILAR TO TODAY AND PRIMARILY DEPEND ON CLOUD COVER...
RANGING FROM NEAR 80F IN THE N/NW PIEDMONT TO MID/UPPER 80S IN THE
SANDHILLS AND COASTAL PLAIN. -VINCENT
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 318 PM MONDAY...
TUESDAY NIGHT...APPROACH OF A WEAK MID-UPPER LEVEL DISTURBANCE
COUPLED WITH AN INCREASINGLY MOIST AIR MASS WILL SUPPORT THE
POTENTIAL FOR A FEW SHOWERS/ISOLATED THUNDER WELL INTO THE
NIGHT...MAINLY OVER THE NW PIEDMONT. INCREASING/THICKENING CLOUD
COVER AND A LIGHT SLY WIND WILL RESULT IN A FAIRLY UNIFORM TEMP
FIELD OVERNIGHT. MIN TEMPS UPPER 60S TO AROUND 70.
WEDNESDAY AND WEDNESDAY NIGHT...THE MID-UPPER LEVEL TROUGH TRANSLATE
SLOWLY EWD TOWARD AND ACROSS THE MID ATLANTIC AND CAROLINAS WED
AFTERNOON-EVENING. 12Z GFS NOT TOO IMPRESSIVE WITH ITS CONVECTIVE
PARAMETERS WED AFTERNOON-EVENING ...DEPICTING MARGINAL/SLIGHT
INSTABILITY AT BEST. STILL...FAVORED LOW LEVEL CONFLUENCE OVER THE
WESTERN PIEDMONT DURING PRIME HEATING SUPPORT HIGH CHANCE POP IN
THIS REGION....WITH POPS TAPERING TO SLIGHT CHANCE OVER THE SOUTHERN
COASTAL PLAINS AND SANDHILLS. MORE CLOUDS THAN SUN WILL LIMIT NORMAL
DIURNAL TEMP RISE IN THE WEST-NW WHERE MAX TEMPS EXPECTED TO BE
LOWER 80S. PARTIAL SUN OVER THE SE HALF SHOULD WARM TEMPS WELL INTO
THE 80S. CONSIDERABLE CLOUDINESS WEDNESDAY NIGHT WILL MAINTAIN HUMID
CONDITIONS. MIN TEMPS AROUND 70/LOWER 70S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 318 PM MONDAY...
THURSDAY...
LINGERING MID-UPPER LEVEL TROUGH WILL MAINTAIN A DECENT THREAT FOR
SCATTERED SHOWERS AND THUNDERSTORMS THURSDAY AS LOW LEVEL
CONVERGENCE PROJECTED TO BE MAXIMIZED OVER OUR REGION. ONLY CAVEAT
IS THAT BUILDING MID-UPPER LEVEL HEIGHTS MAY RESULT IN THE
DEVELOPMENT OF A LAYER OF WARM AIR ALOFT...POSSIBLY CAPPING AIR MASS
AND LIMITING CONVECTIVE DEVELOPMENT. HOWEVER CONSIDERING THE AMOUNT
OF LOW LEVEL CONVERGENCE AND AVAILABLE MOISTURE SUPPORT CHANCE POPS
THURSDAY.
FRIDAY-SATURDAY....SUB TROPICAL RIDGE PROJECTED TO EXPAND/STRENGTHEN
WEST-TO-EAST ACROSS THE LOWER MS VALLEY AND SE U.S. THIS WILL PLACE
CENTRAL NC ON THE PERIPHERY OF THIS WEATHER SYSTEM. WEAK
PERTURBATIONS TRAVERSING EWD COUPLED WITH AVAILABLE MOISTURE AND
INSTABILITY SUGGEST A THREAT FOR SCATTERED SHOWERS AND STORMS EACH
DAY...MORE SO ON SATURDAY AFTERNOON AS A S/W IN THE NORTHERN STREAM
PROPELS A SFC FRONT SWD TOWARD CENTRAL NC. PLAN TO HAVE
CHANCE-SLIGHT CHANCE POPS NW-SE ACROSS THE REGION FRIDAY WITH HIGH
CHANCE POPS MOST LOCATIONS LATE SATURDAY-SATURDAY NIGHT.
SUNDAY INTO MONDAY....LATEST GFS HAS TRENDED TOWARD THE MORE
PROGRESSIVE ECMWF WHICH PUSHES THE SFC COLD FRONT SWD ACROSS CENTRAL
NC SUNDAY...AND POSITIONED SOUTH OF THE REGION MONDAY. THIS SUGGEST
A DECREASING THREAT FOR SCATTERED SHOWERS AND STORMS. PLAN TO
MAINTAIN MENTION OF A SMALL CHANCE BOTH DAYS...SUNDAY TO ACCOUNT FOR
POSSIBLE MODEL TIMING ISSUES WITH THE FRONTAL PASSAGE...AND ON
MONDAY AS DEVELOPING NW FLOW ALOFT MAY PROVIDE AN AVENUE FOR
DISTURBANCES ROTATING AROUND A DEEP CLOSED UPPER LOW OVER THE
NORTHERN LAKES TO TRANSLATE INTO OUR REGION.
TEMPS THURSDAY THROUGH MONDAY DEPENDENT UPON EXTENT OF CLOUD COVER
AND AREAL COVERAGE OF CONVECTION. EXPECT AFTERNOON TEMPS TO AVERAGE
A COUPLE OF DEGREES BELOW NORMAL WHILE OVERNIGHT TEMPS WILL BE 3-5
DEGREES ABOVE NORMAL.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 145 AM TUESDAY...
SHOWERS CONTINUE TO DEVELOP WEST OVER THE WESTERN PIEDMONT AND
FOOTHILLS WHERE WEAK WARM ADVECTION AND UPSLOPE FLOW IS MORE
PROMINENT...BUT THE TREND HAS BEEN FOR THE SHOWERS TO DISSIPATE AS
THEY DRIFT EAST NEAR KINT/KGSO. HIGH PRESSURE OFF THE MID-ATLANTIC
COAST IS FORECAST TO REMAIN RELATIVELY STATIONARY TODAY...WITH
LITTLE CHANGE IN THE FLOW OVER CENTRAL NC. THUS...MOISTURE WILL
CONTINUE TO BE BEST OVER WESTERN NC AND SHOWERS OR STORMS WILL
STRUGGLE TO MOVE ACROSS THE PIEDMONT. FORECAST SOUNDINGS SHOW
CEILINGS IN THE 3000-5000 FT RANGE TODAY...ALTHOUGH MVFR CEILINGS
CERTAINLY WILL BE POSSIBLE AT KGSO AND KINT.
OUTLOOK...
EARLY MORNING STRATUS WILL BE A PROBLEM EACH MORNING THIS
WEEK AS A MOIST SOUTHERLY FLOW PERSISTS. THE CHANCE OF SHOWERS AND
STORMS WILL EXIST EACH DAY...PARTICULARLY OVER WESTERN NC. THE
WEATHER WILL BECOME MORE UNSETTLED BY THE END OF THE WEEK AS A COLD
FRONT MOVES INTO THE REGION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD
NEAR TERM...BSD/VINCENT
SHORT TERM..WSS
LONG TERM...WSS
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1131 PM CDT MON AUG 5 2013
.UPDATE...
ISSUED AT 1125 PM CDT MON AUG 5 2013
MAIN QUESTION IS HOW MUCH PRECIP WILL MAKE IT THIS FAR EAST LATER
TONIGHT INTO TUESDAY. BIG MCS NOW IN SOUTHERN KANSAS AND LACK OF
ANY STRONG LOW LEVEL MOISTURE ADVECTION AND WEAK 850 MB JET IS
CAUSING A LOT OF THE ACTIVITY FROM SASK INTO WRN ND TO WEAKEN.
CANADAIAN RADARS SHOW THIS TOO. BUT VORT IS PRETTY STRONG SO DO
FORSEE SOME ACTIVITY TO MAKE IT IN AS FCST OVERNIGHT. 00Z MODELS
AND LATEST HRRR COMING AROUND TO THE IDEA OF A WEAK SFC LOW NR
WILLISTON MOVING SOUTHEAST TO NEAR FARGO AREA BY 16Z TUE WITH
WINDS TURNING NORTHWEST AND NORTH BEHIND IT. 00Z GFS ACTUALLY NOT
BAD WITH QPF THIS RUN....OTHER MODELS TOO MUCH.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 321 PM CDT MON AUG 5 2013
WITH THE CLOUDS CONTINUING TO PUSH EAST SLOWLY ANY CLEARING WILL
BE RELATIVELY SHORT LIVED. CONVECTION STARTING UP OVER EASTERN MT
WILL BEGIN SPREADING IN SOME HIGHER LEVEL CLOUDS TONIGHT. THE MAIN
FORECAST CONCERN WILL SHIFT BACK TO TIMING THE NEXT CHANCE OF PCPN
FOR LATER TONIGHT INTO TUE/TUE NIGHT. TRIED TO FOLLOW THE HIGH RES
MODELS FOR THE ARRIVAL TIME OF PCPN TONIGHT AND THEN KIND OF A
BLEND FOR TIMING THE BEST CHANCES FROM WEST TO EAST THRU TUE. SPC
HAS SOUTHWEST ND AND WESTERN SD IN A SLIGHT RISK FOR DAY1. THIS IS
THE AREA ONCE AGAIN WHICH HAS HEATED OUT WITH SLIGHTLY HIGHER DEW
POINTS. RESULTANT MLCAPE VALUES ARE PUSHING TO AROUND 1500J/KG
WITH DECENT SHEAR ALSO PRESENT. SO ONCE AGAIN THE CONVECTION IS
FIRING WEST OF THE FA. THE NEXT DECENT UPSTREAM SHORT WAVE IS
DROPPING INTO NORTHWEST MT. THIS WAVE WILL BEGIN AN EASTWARD
SHIFT TAKING IT INTO EASTERN MT/WESTERN ND BY 06Z THEN CENTRAL ND
BY 12Z. THEREFORE IT SEEMS REASONABLE THAT SOME LINGERING
CONVECTION THAT FIRES OUT WEST MAY HOLD TOGETHER AS IT TRACKS INTO
THE FA LATE. ANOTHER AREA THAT WILL BEAR WATCHING IS A COLD FRONT
UP IN THE MANITOBA LAKES REGION NORTH OF WINNIPEG. AS THE WESTERN
WAVE APPROACHES CENTRAL ND BY 12Z TUE IT WILL HELP ORGANIZE A WEAK
SFC LOW IN THIS SAME GENERAL VICINITY. THE COLD FRONT SHOULD GET
DRAWN DOWN INTO THE NORTHERN FA BY 12Z. THE HIGH RES MODELS SHOW
THE POTENTIAL FOR SOME PCPN ALONG THIS BOUNDARY TOO. SOME WEAK
WARM ADVECTION AND LOW LEVEL JET ENERGY MAY ALSO COME INTO PLAY
AFTER DARK TOO...FEEDING INTO CENTRAL ND IN THE LATE EVENING.
ALL OF THE ABOVE MENTIONED FEATURES KIND OF MELD OVER THE FA ON
TUE WITH THE COLD FRONT SLOWLY SLIDING FROM NORTH TO SOUTH AND THE
SHORT WAVE FROM WEST TO EAST. KEPT LIKELY CHANCES FOR PCPN AND
TRIED TO BREAK THEM OUT TO SHOW THE WEST TO EAST PROGRESS THRU THE
DAY. SPC DAY2 HAS A SLIGHT RISK JUST TO THE SOUTH OF THE FA SO HOW
FAST THE FRONT DROPS SOUTH WILL LIKELY DETERMINE IF ANY TSTMS CAN
BECOME STRONG TO SEVERE ACROSS THE FAR SOUTH TUE AFTERNOON. STILL
EXPECT ANY LINGERING PCPN TO EXIT THE EAST TUE EVENING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 321 PM CDT MON AUG 5 2013
KEPT WED PCPN FREE WITH THE NEXT PCPN CHANCES COMING WED NIGHT
INTO THU. PRETTY MUCH LEFT THE PCPN CHANCES FOR THIS NEXT EVENT AS
IS FOR NOW.
FRIDAY TO MONDAY...MODEL AGREEMENT CONTINUES WITH THE SAME OLD
PATTERN OF CONFLUENT NW FLOW AT 500MB...WHICH MEANS DRY AND
SLIGHTLY COOLER THAN NORMAL FOR THE NORTHERN PLAINS. THERE REMAINS
A CHANCE FOR SOME SHOWER ACTIVITY AT SOME POINT OVER THE NEXT
WEEKEND BUT WITH UNCERTAINTY IN TIMING AND SMALL AREAL COVERAGE
THAT A WEAK WAVE MAY INDUCED PRECIP...HAVE KEPT THE MAJORITY OF
THE CWFA COMPLETELY DRY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1125 PM CDT MON AUG 5 2013
HIGH CLOUDS SPREADING ACROSS THE AREA ATTM...AND QUESTION WILL BE
TIMING ANY SHOWERS. THUNDER THREAT IS WEAKENING AND SHOULD BE
ISOLD OVERNIGHT INTO TUESDAY MORNING. EXPECT SHOWERS TO COME FROM
BASES AOA 6000 FT AGL AS SYSTEM MOVES THROUGH. WINDS TURN NORTH-
NORTHWEST TUESDAY MORNING IN DVL REGION THEN REACHING SE
ND/WCNTRL MN TUES EARLY-MID AFTN.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...GODON
LONG TERM...GODON/JK
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
430 AM EDT TUE AUG 6 2013
.SYNOPSIS...
WEAK DISTURBANCE EXITS THE MOUNTAIN COUNTIES THIS MORNING. INSTABILITY
INCREASES LATE TODAY AND OVERNIGHT. STRONGER MID LEVEL DISTURBANCE
PASSES WEDNESDAY. MORE ROUNDS OF CONVECTION INTO THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
ONCE YOU GET SPOILED BY THOSE RARE LOWER DEW POINTS IN THE DOG DAYS
OF SUMMER...YOU HATE TO SEE THEM LEAVE. THE INITIAL MID LEVEL
DISTURBANCE WAS CROSSING THE CENTRAL WV MOUNTAINS THIS EARLY HOUR OF
08Z. A SECONDARY 500 MB VORT IS INDICATED ON THE 07Z RAP MODEL
PASSING N OF BKW AROUND 09-10Z.
MEANWHILE...WHILE THE MID LEVEL MOISTURE INCREASED FROM THE WEST
LAST NIGHT...THE LOWER LEVEL MOISTURE MADE ITS FASTEST INITIAL
CHARGE NORTH...ON THE EASTERN SLOPES OF THE APPALACHIANS. YET...THE
925 TO 850 MB FLOW REMAINS WEAK AND STARTS VEERING MORE TOWARD SOUTH
AND SOUTHWEST. SO TOUGH CLOUD FORECAST TODAY FOR AREAS FROM BKW EAST
INTO THE UPPER GREENBRIER VALLEY.
MEANWHILE...IN THE WAKE OF THE MID LEVEL DISTURBANCE...BREAKS IN THE
CLOUDS COULD YIELD SOME BRIEF FOG IN THE MID OHIO VALLEY FOR DAWN.
NO MAJOR CHANGES TODAY...KEPT A 20/30 POPS OVER THE MOUNTAINS FOR
THE AFTERNOON HEATING IN THE WEAK FLOW. ALSO KEPT THE POSSIBILITY
OF CONVECTION FORMING FOR OUR NE KENTUCKY AND THE TRI STATE AROUND
HTS AFTER 18Z.
MOST MODELS LIKE THE ECMWF...GFS HOLD US DRY OVERNIGHT. BUT NAM
SHOWS MINOR FEATURES WITH INCREASING LOW LEVEL WINDS/FORCING AT
925 MB TO 850 MBS. IT IS TOO PREMATURE TO REMOVE POPS IN OUR
SOUTHERN AND WESTERN COUNTIES FOR TONIGHT. I DID TRY TO HOLD THE
ROUTE 50 CORRIDOR INCLUDING PKB TO CKB DRY MOST OF THE NIGHT. HAVE
POPS INCREASING INTO THE 30 TO 40 PERCENT RANGE ACROSS THE SOUTH
OVERNIGHT. CERTAINLY THE LONGER WE CAN HOLD OFF AREAS OF HEAVIER
CONVECTION THE BETTER...CONSIDERING THE ACTIVE PATTERN INTO THIS
WEEKEND.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
NEW 00Z MODELS LEAVE SOME QUESTION TO HOW THINGS WILL PLAY OUT
THROUGH THE SHORT TERM...AS ECMWF HAS MOVED BEST UPPER LEVEL SUPPORT
FARTHER NORTH WHILE NAM/GFS HAVE BEEN FAIRLY CONSISTENT WITH
PREVIOUS RUNS LOCATION WISE. ALL MODELS HAVE SLOWED DOWN A BIT WITH
THE PRECIP FOR WEDNESDAY...SO TRENDED THAT WAY. DESPITE THE MODEL
DIFFERENCES...THUNDERSTORMS LIKELY WEDNESDAY INTO WEDNESDAY NIGHT
AND WITH PW VALUES CLIMBING ABOVE 2 INCHES HEAVY RAIN IS ALSO
LIKELY. TRAIN OF VORT MAXES CONTINUES AS COLD FRONT APPROACHES
THURSDAY THROUGH FRIDAY. GFS STILL SHOWS THE COLD FRONT TRYING TO
PUSH THROUGH FRIDAY NIGHT...HOWEVER NEW ECMWF STALLS THE SURFACE
FRONT NEAR TO JUST NORTH OF CWA. THINK THE ECMWF MAY BE ON TO
SOMETHING...BUT WITH THIS BEING THE FIRST INDICATION...WON/T JUMP
FULLY ON IT YET. DID INCREASE LOWS FRIDAY NIGHT QUITE A BIT...WITH
ONLY MINIMAL CHANGES MADE TO OTHER TEMPS.
WILL CONTINUE WATER CONCERN MENTION IN HWO. THINK MOST LOCATIONS
SHOULD BE ABLE TO HANDLE WEDNESDAYS BATCH OF HEAVY RAIN SINCE WE
HAVE HAD SOME TIME TO DRY OUT SINCE LAST SIGNIFICANT RAIN...SO AM
MORE CONCERNED WITH REPETITIVE STORMS ADDING UP THROUGH THE END OF
THE WEEK. WITH THAT SAID...CAN NOT RULE OUT LOCALIZED ISSUES
WEDNESDAY DUE TO DOWNPOURS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
USED WPC THINKING FOR THIS PORTION OF THE FORECAST...WITH SOME MINOR
TWEAKS. A COLD FRONT SHOULD BE LOCATED JUST TO OUR SOUTHEAST
SATURDAY. A REINFORCING COLD FRONT SHOULD THEN PUSH SOUTHEAST
SATURDAY/SATURDAY NIGHT...BEFORE WEAK HIGH PRESSURE TAKES CONTROL BY
MONDAY.
BELOW NORMAL TEMPERATURES SHOULD PREVAIL THROUGH THE PERIOD.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
THE OLD SQUEEZE PLAY...WITH THE LAST OF THE DRIER AIR EXITING.
MID LEVEL DISTURBANCES IN THE WNW FLOW AT 700 MB CROSSING 06Z TO 12Z
WILL CAUSE SOME SPOTTY LIGHT RAIN SHOWERS MAINLY CKB TO EKN VCNTY.
MEANWHILE...FLOW AROUND 925 MB FROM THE EAST AND SOUTHEAST...WITH
LOW LEVEL MOISTURE INCREASING NORTH...UP THE EASTERN SLOPES OF THE
APPALACHIANS. THAT FLOW IN VERY WEAK AND BECOMES MORE SOUTHERLY BY
MIDDAY TODAY. THIS LOWERS MY CONFIDENCE IN THE CEILINGS ALONG THE
SPINE OF THE APPALACHIANS ON EAST INTO THE GREENBRIER VALLEY.
BECKLEY IN THE SOUTHERN MOUNTAINS MAY BE ON THE WESTERN FRINGE OF
THIS MAXIMUM IN LOW LEVEL MOISTURE THIS MORNING...SO HAVE A
SCATTERED TO BROKEN DECK THERE AROUND 2 THSD FT AGL.
THERE MAY BE SOME BREAKS IN THE MID CLOUDS OVER THE WESTERN LOWLANDS
DURING THE PREDAWN...SO COULD STILL SEE SOME BRIEF 1 TO 3 MILES IN
FOG TOWARD DAWN.
A FEW SHOWERS OR THUNDERSTORMS COULD FORM IN THE AFTERNOON HEATING
OVER THE MOUNTAINOUS COUNTIES. INSTABILITY INCREASES IN THE TRI
STATE VCNTY OF HTS BY 21Z INCLUDING EASTERN KENTUCKY...SO SOME
THUNDERSTORMS COULD DEVELOP THERE LATE TODAY AND LINGER INTO THIS
EVENING.
WITH MOISTURE INCREASING AT 850 MB AND BELOW WEST OF THE MOUNTAINS
TONIGHT...HAVE MORE WIDESPREAD CEILINGS A 3 TO 4 THSD FT DEVELOPING
00Z TO 06Z WEDNESDAY IN THE WESTERN LOWLANDS. VSBY COULD BE 5 TO 6
MILES IN HAZE WITH INCREASING SURFACE DEW POINTS. INSTABILITY
LINGERS OVERNIGHT...SO HAVE CHANCE POPS FOR CONVECTION CREEPING NE
CENTRAL WV AND CRW VCNTY. SHOULD REMAIN DRY PKB TO CKB VCNTY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: IF MORE BREAKS DEVELOP SOONER...THICKER FOG
COULD DEVELOP THAN FORECAST DURING THE 09Z TO 12Z TIME FRAME IN THE
WESTERN LOWLANDS INCLUDING THE MID OHIO VALLEY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE TUE 08/06/13
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15
CRW CONSISTENCY H M M H M H H H H H H H
HTS CONSISTENCY H M M M M H H H H H H H
BKW CONSISTENCY M M M M M M M M M H H H
EKN CONSISTENCY H M M H H M H H H H H H
PKB CONSISTENCY L L L L H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 06Z WEDNESDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION WEDNESDAY INTO SATURDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...JSH
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
214 AM EDT TUE AUG 6 2013
.SYNOPSIS...
WEAK DISTURBANCES WILL MOVE ACROSS THE AREA TONIGHT AND TUESDAY. A
MORE PRONOUNCED SYSTEM WILL MOVE ACROSS THE AREA LATE TUESDAY
NIGHT INTO WEDNESDAY. A COLD FRONT WILL MOVE THROUGH THE REGION
WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ABUNDANT MOISTURE ALOFT IN NORTHWESTERLY FLOW IS HELPING TO BRING
PATCHES OF SPRINKLES AND LIGHT RAIN ACROSS CENTRAL INDIANA AND
CENTRAL OHIO THIS EVENING. THE TREND OVER THE PAST FEW HOURS HAS
BEEN TO WEAKEN THE AREAS OF PRECIPITATION. HAVE FORECAST THESE
SHOWERS TO GRADUALLY DISSIPATE AS THEY SHIFT EAST TO SOUTHEAST
THROUGH THE LATE EVENING. OF NOTEWORTHINESS...LATEST RUC IS TRYING
TO REDEVELOP SHOWERS ACROSS NORTHERN INDIANA EARLY IN THE MORNING
AND THESE SHOWERS COULD MAKE IT TO OUR NORTHWESTERN ZONES AROUND
SUNRISE. THIS MORNING ACTIVITY IS ALSO COARSELY DEPICTED IN THE
12Z ECMWF AND THEREFORE MAY NEED TO INTRODUCE POPS ACROSS THOSE
ZONES AFTER 11Z IF THESE ADDITIONAL SHOWERS BEGIN TO FILL IN
UPSTREAM OVER THE NEXT FEW HOURS. OTHERWISE...EXPECT MOSTLY CLOUDY
SKIES WITH TEMPERATURES FALLING INTO THE UPPER 60S ACROSS THE
WEST...TO THE UPPER 50S ACROSS OUR EASTERN ZONES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
A WEAK DISTURBANCE WILL BRING A CHANCE FOR SOME SHOWERS AND
THUNDERSTORMS ACROSS THE FA ON TUESDAY. A MORE WELL DEFINED SHORT
WAVE WILL APPROACH THE AREA TUESDAY NIGHT INTO WEDNESDAY. THIS
FEATURE WILL BRING WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY TO
THE AREA. MODELS HAVE BEEN INCONSISTENT WITH WHERE THE HEAVIEST
RAIN WILL BE WITH THIS FEATURE. THE BEST CHANCE FOR HEAVIER
RAINFALL WILL BE ACROSS SOUTHERN PORTIONS OF THE FA AND THEREFORE
ADDED FLOODING POTENTIAL IN TO THE HWO ACROSS THIS AREA. DECIDED
AGAINST A FLASH FLOOD WATCH DUE TO RELATIVELY HIGH FFG VALUES AND
MODEL INCONSISTENCIES WITH WHERE THE HEAVIEST RAINFALL WILL OCCUR.
ADDITIONAL PRECIPITATION WILL BE POSSIBLE ACROSS THE FA WEDNESDAY
NIGHT AS A COLD FRONT MOVES THROUGH.
SOUTHERLY FLOW ACROSS THE FA ON TUESDAY WILL ALLOW FOR
TEMPERATURES TO RISE INTO THE 80S. TEMPERATURES ON WEDNESDAY WILL
BE COOLER WITH HIGHS IN THE UPPER 70S TO LOWER 80S DUE TO MORE
WIDESPREAD PRECIPITATION AND CLOUD COVER ACROSS THE FA.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
MOST GUIDANCE HAS TRENDED TOWARDS A DRIER SOLUTION FOR THURSDAY. A
WEAK FRONTAL BOUNDARY WILL REMAIN ACROSS THE SOUTH BUT FORCING DOES
NOT LOOK PARTICULARLY STRONG AT THIS TIME. SO HAVE ONLY KEPT LOW
CHANCE POPS IN FOR THAT PERIOD.
CHANCE OF RAIN WILL INCREASE AGAIN LATE THURSDAY NIGHT AND
PARTICULARLY INTO FRIDAY AS A WAVE MOVES ALONG THE STALLED FRONT.
HAVE INCREASED POPS TO LIKELY ACROSS THE SOUTHERN COUNTIES. THIS
WILL PUSH OFF TO THE EAST DURING FRIDAY NIGHT. HIGH PRESSURE WILL
BUILD IN FOR THE WEEKEND. THERE IS THE POTENTIAL FOR A WEAK SYSTEM
TO SWING INTO THE REGION BY MONDAY. BUT SIGNAL IS NOT VERY STRONG
AND AT DAY 7 HAVE KEPT ANY CHANCE OF RAIN RATHER LOW.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
NORTHWEST FLOW WITH MID TO HIGH LEVEL CLOUDS MOVING ACROSS THE AREA
THROUGH THE EARLY MORNING HOURS. UPSTREAM OF THIS DECK...A LARGE AREA
OF VFR LOW CLOUDS AROUND 5000 FEET APPEARS WILL SPREAD ACROSS OUR
AREA. THE VFR LOW CLOUD DECK WILL LIKELY REMAIN ACROSS THE TAFS
THROUGH THE DAY...BECOMING SCATTERED AT TIMES. SHOWERS WILL BECOME
POSSIBLE LATE IN THE AFTERNOON WEST OF INTERSTATE 75...WITH THE
BEST CHANCE FOR A SHOWER BEING AT KDAY. SINCE LIKELIHOOD IS LOW HAVE
KEPT THE TAFS DRY THRU THE DAY. HAVE A MENTION OF VCSH AT 30 HOUR
KCVG TAF SITE TOWARD SUNRISE WEDNESDAY WITH PRECIP APPROACHING
FROM THE SW.
OUTLOOK...THUNDERSTORMS POSSIBLE WEDNESDAY INTO THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...NOVAK
NEAR TERM...LATTO
SHORT TERM...NOVAK
LONG TERM...
AVIATION...AR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
448 AM EDT TUE AUG 6 2013
.SYNOPSIS...
AN INCREASINGLY MOIST AND UNSETTLED WEATHER PATTERN WILL PERSIST
INTO THE FIRST PART OF THE WEEKEND...AS MULTIPLE FRONTS APPROACH
AND EVENTUALLY MOVE ACROSS THE REGION. A GRADUAL WARMING TREND TO
NEAR NORMAL TEMPERATURES IS EXPECTED THROUGH THE END OF THE
WEEK...BEFORE ANOTHER SHOT OF SEASONABLY COOL AIR ARRIVES ON
SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
IR SATL TRENDS SINCE MIDNIGHT HAVE DEPICTED A NOTABLE INCREASE IN
LOW-MID LEVEL CLOUDS ACRS A GOOD PORTION OF THE CWA. THE IR SATL
IMAGERY ALSO SHOWS FOG IN THE NRN RIVER/STREAM VALLEYS...WHERE
AIR/WATER TEMP SPREADS ARE AGAIN RUNNING 25-30 DEGREES. VWP/S FROM
IAD/BWI INDICATE THE 925-850MB FLOW HAS VEERED TO THE S-SW...AND
LATEST RUC MESO ANALYSIS SHOW A MSTR AXIS /+13-15C 850MB DEWPTS/
EXTENDING NWD ALONG THE ERN SLOPES OF THE APPLCHNS ON THE WRN
PERIPHERY OF DEPARTING SFC HIGH. THIS ENHANCED MSTR FLUX APPEARS
TO BE OVERRUNNING A WARM FRONT OVER NRN VA WITH DEVELOPING SHOWERS
STARTING TO PEEL NWD FROM THE MAIN W-E RAIN BAND TWD SRN MD.
THEREFORE CANT RULE OUT AN ISOLD SHOWER OVER THE FAR S-CNTRL OR
SERN ZONES PRIOR TO 12Z.
WEAK BUT PERSISTENT LLVL WARM AIR/MSTR ADVECTION AND BROAD ISENT
LIFT OVERRUNNING THE WARM FRONT OVER NRN VA WILL LKLY SUPPORT THE
DEVELOPMENT OF SCT SHOWERS...SPREADING FROM SOUTH TO NORTH DURING
THE MID-LATE MORNING THRU THE AFTN HOURS. SHORTWAVES EMBEDDED
WITHIN THE SEASONABLY STRONG WNW FLOW ALOFT ON THE SRN PERIPHERY
OF CLOSED/SLOW-MOVING UPPER LOW CENTERED OVER NRN MANITOBA/ONTARIO
WILL PROVIDE ENOUGH LARGE SCALE LIFT TO AID IN SHOWER DEVELOPMENT.
A FEW ISOLD THUNDERSTORMS WITH LOCALIZED HEAVY DOWNPOURS MAY ALSO
DEVELOP IN THE AFTN...BUT FOR THE MOST PART INSTABILITY WILL BE
WEAK WITH MEAN CAPES GENERALLY AOB 500 J/KG. MODEL QPFS ARE IN
REASONABLY GOOD AGREEMENT IN KEEPING THE BETTER RAINFALL AXIS TO
THE SOUTH OF THE MASON-DIXON LINE FROM SRN VA NEWD INTO DE...WITH
JUST LGT AMTS /0.1-0.25 INCHES/ OVER CNTRL AND SERN PA. THE
STEADILY INCREASING MSTR AND CLOUDS WILL KEEP MAX TEMPS IN THE
LOW TO MID 70S...AVERAGING A FEW TO SEVERAL DEGREES BELOW NORMAL
DEPENDING ON LOCATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE AFOREMENTIONED WARM FRONT WILL LIFT NWD INTO CNTRL PA TONIGHT
WITH BROAD LLVL SWLY FLOW CONTINUING TO ADVECT HIGHER PWS/60+
DEWPOINTS INTO THE AREA. MDL CONSENSUS STILL FAVORS THE ERN 1/2 TO
1/3 OF THE CWA WITH THE BEST CHC FOR LGT SHOWERS OVERNIGHT INTO
EARLY WEDNESDAY MORNING. IN CONTRAST TO DAYTIME HIGHS...THICKENING
CLOUDS PLUS INCREASING MSTR/DEWPOINTS WILL RESULT IN WARMER THAN
AVG MIN TEMPS WITH READINGS IN THE LOW-MID 60S.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
A ZONAL FLOW ACROSS THE NORTHERN CONUS WILL PREVAIL ACROSS THE
REGION FROM WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. NUMEROUS
EMBEDDED DISTURBANCES WILL ACT ON MONSOONAL MOISTURE FROM THE
SOUTHWESTERN UNITED STATES AND NEARLY STATIONARY BOUNDARY LAYER
FORCING TO PRODUCE A LOCALLY HEAVY RAIN/FLASH FLOOD THREAT ON THU-
FRI BEFORE DRIER AND COOLER CONDS RETURN BY LATE SAT AND SUN.
CLOUDS/PCPN SHOULD OFFSET WARMING ALOFT AND KEEP TEMPS NEAR TO
SLIGHTLY BELOW AVG. MDL DATA INDICATES THE COLD FRONT WILL BECOME
MUCH LESS PROGRESSIVE OR STALL OUT OVER THE UPPER OH VLY WED NGT
INTO THUR.
MODELS AND ENS MEANS CENTER AROUND THE GENERAL IDEA OF A
MODERATELY SLOW PROGRESSION OF THE CLOSED LOW TRACKING EWD BTWN
THE GRT LKS AND HUDSON BAY FROM THU THRU SAT. AT THE SFC...THE
COLD FRONT TURN Q-STNRY BNDRY IN THE OH VLY...WHICH WAS ASSOCIATED
WITH THE LEAD SHORTWAVE TROUGH...SHOULD PUSH SLOWLY EWD ACRS CNTRL
PA ON DAY4/THU. THE SFC PATTERN GETS QUITE COMPLICATED FRI-SAT AS
WPC PROGS SHOW THE FIRST BOUNDARY STALLING OUT OVER THE SRN MID-
ATLC STATES AND SECONDARY COLD FRONT APPROACHING FROM THE GREAT
LAKES. WAVES OF LOW PRESSURE RIDING NEWD ALONG THESE ENCROACHING
FRONTS COULD KEEP UNSETTLED CONDS IN THE FCST THRU THE FIRST PART
OF THE WEEKEND.
ANOTHER PUSH OF WESTERLIES SHOULD OVERSPREAD THE AREA BY SUNDAY
AND NUDGE THE SECOND FRONT EWD TO OR OFF THE COAST. A LARGE AREA OF
CANADIAN HIGH PRESSURE SHOULD SUPPLY ANOTHER REFRESHINGLY COOL/DRY
AIRMASS INTO THE GREAT LAKES AND NORTHEAST BY NEXT SUNDAY. DON`T
EXPECT TEMPS TO FLUCTUATE VERY MUCH THRU THE MEDIUM
RANGE...CONTINUING TO AVG NEAR TO SLIGHTLY BELOW NORMAL FOR EARLY
AUGUST.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
SLY RETURN FLOW DEVELOPING ON THE WRN PERIPHERY OF HIGH PRES
SLIDING OFF THE EAST COAST WILL BRING INCREASING MSTR AND
THICKENING LOW-MID CLOUDS INTO CNTRL PA THRU TONIGHT. A LLVL MSTR
CONVERGENCE AXIS EXTENDING NWD FM THE SE STATES ALONG THE ERN
SLOPES OF THE APPLCHNS IS LKLY RESPONSIBLE FOR THE AREA OF 6-8KFT
CIGS OVER THE S-CNTRL AND SERN TAFS. EXPECT THESE CIGS TO THICKEN
AND LOWER 1-2KFT INTO THE MID MORNING AS BLYR COOLS AND LLVL FLOW
CONTINUES VEERING TO THE SOUTH-SOUTHEAST. THE INCREASINGLY MOIST
LLVL FLOW WILL OVERRUN A WARM FRONT LIFTING SLOWLY NEWD FROM THE
TN VLY AND CNTRL APPLCHNS AND SUPPORT SCT SHOWERS /WITH ISOLD
TSRA/ INTO THE AFTN. THE S-CNTRL AND SERN AIRFIELDS STAND THE
GREATEST CHC TO BE IMPACTED BY THE SHOWER ACTIVITY. EXPECT CIG
RESTRICTIONS TO BECOME MORE WIDESPREAD FROM TONIGHT INTO EARLY
WEDNESDAY AS SLY FLOW AND LLVL MSTR CONTINUES TO INCREASE AS WARM
FRONT LIFTS NEWD ACRS THE AIRSPACE.
OUTLOOK...
WED-FRI...MVFR/VFR. TWO FRONTAL SYSTEMS WILL BRING PERIODS OF
SHOWERS AND OCNL TSTMS.
SAT...BCMG VFR AS HIGH PRES BUILDS SEWD FROM THE UPPER MIDWEST.
&&
.EQUIPMENT...
KCCX HAS SUFFERED MULTIPLE PEDESTAL DYNAMIC FAULTS EARLY THIS
MORNING...CAUSING IT TO GO INTO STAND-BY MODE. THE RADAR WILL
REMAIN IN STAND-BY MODE UNTIL OUR TECHNICIANS CAN DIAGNOSE THE
PROBLEM LATER THIS MORNING. WE APOLOGIZE FOR THE INCONVENIENCE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...DEVOIR/GARTNER
AVIATION...STEINBUGL
EQUIPMENT...STEINBUGL/DEVOIR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
433 AM EDT TUE AUG 6 2013
.SYNOPSIS...
AN INCREASINGLY MOIST AND UNSETTLED WEATHER PATTERN WILL PERSIST
INTO THE FIRST PART OF THE WEEKEND...AS MULTIPLE FRONTS APPROACH
AND EVENTUALLY MOVE ACROSS THE REGION. A GRADUAL WARMING TREND TO
NEAR NORMAL TEMPERATURES IS EXPECTED THROUGH THE END OF THE
WEEK...BEFORE ANOTHER SHOT OF SEASONABLY COOL AIR ARRIVES ON
SUNDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
IR SATL TRENDS SINCE MIDNIGHT HAVE DEPICTED A NOTABLE INCREASE IN
LOW-MID LEVEL CLOUDS ACRS A GOOD PORTION OF THE CWA. THE IR SATL
IMAGERY ALSO SHOWS FOG IN THE NRN RIVER/STREAM VALLEYS...WHERE
AIR/WATER TEMP SPREADS ARE AGAIN RUNNING 25-30 DEGREES. VWP/S FROM
IAD/BWI INDICATE THE 925-850MB FLOW HAS VEERED TO THE S-SW...AND
LATEST RUC MESO ANALYSIS SHOW A MSTR AXIS /+13-15C 850MB DEWPTS/
EXTENDING NWD ALONG THE ERN SLOPES OF THE APPLCHNS ON THE WRN
PERIPHERY OF DEPARTING SFC HIGH. THIS ENHANCED MSTR FLUX APPEARS
TO BE OVERRUNNING A WARM FRONT OVER NRN VA WITH DEVELOPING SHOWERS
STARTING TO PEEL NWD FROM THE MAIN W-E RAIN BAND TWD SRN MD.
THEREFORE CANT RULE OUT AN ISOLD SHOWER OVER THE FAR S-CNTRL OR
SERN ZONES PRIOR TO 12Z.
WEAK BUT PERSISTENT LLVL WARM AIR/MSTR ADVECTION AND BROAD ISENT
LIFT OVERRUNNING THE WARM FRONT OVER NRN VA WILL LKLY SUPPORT THE
DEVELOPMENT OF SCT SHOWERS...SPREADING FROM SOUTH TO NORTH DURING
THE MID-LATE MORNING THRU THE AFTN HOURS. SHORTWAVES EMBEDDED
WITHIN THE SEASONABLY STRONG WNW FLOW ALOFT ON THE SRN PERIPHERY
OF CLOSED/SLOW-MOVING UPPER LOW CENTERED OVER NRN MANITOBA/ONTARIO
WILL PROVIDE ENOUGH LARGE SCALE LIFT TO AID IN SHOWER DEVELOPMENT.
A FEW ISOLD THUNDERSTORMS WITH LOCALIZED HEAVY DOWNPOURS MAY ALSO
DEVELOP IN THE AFTN...BUT FOR THE MOST PART INSTABILITY WILL BE
WEAK WITH MEAN CAPES GENERALLY AOB 500 J/KG. MODEL QPFS ARE IN
REASONABLY GOOD AGREEMENT IN KEEPING THE BETTER RAINFALL AXIS TO
THE SOUTH OF THE MASON-DIXON LINE FROM SRN VA NEWD INTO DE...WITH
JUST LGT AMTS /0.1-0.25 INCHES/ OVER CNTRL AND SERN PA. THE
STEADILY INCREASING MSTR AND CLOUDS WILL KEEP MAX TEMPS IN THE
LOW TO MID 70S...AVERAGING A FEW TO SEVERAL DEGREES BELOW NORMAL
DEPENDING ON LOCATION.
&&
.SHORT TERM /TONIGHT/...
THE AFOREMENTIONED WARM FRONT WILL LIFT NWD INTO CNTRL PA TONIGHT
WITH BROAD LLVL SWLY FLOW CONTINUING TO ADVECT HIGHER PWS/60+
DEWPOINTS INTO THE AREA. MDL CONSENSUS STILL FAVORS THE ERN 1/2 TO
1/3 OF THE CWA WITH THE BEST CHC FOR LGT SHOWERS OVERNIGHT INTO
EARLY WEDNESDAY MORNING. IN CONTRAST TO DAYTIME HIGHS...THICKENING
CLOUDS PLUS INCREASING MSTR/DEWPOINTS WILL RESULT IN WARMER THAN
AVG MIN TEMPS WITH READINGS IN THE LOW-MID 60S.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
A ZONAL FLOW ACROSS THE NORTHERN CONUS WILL PREVAIL ACROSS THE
REGION FROM WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. NUMEROUS
EMBEDDED DISTURBANCES WILL ACT ON MONSOONAL MOISTURE FROM THE
SOUTHWESTERN UNITED STATES AND NEARLY STATIONARY BOUNDARY LAYER
FORCING TO PRODUCE A LOCALLY HEAVY RAIN/FLASH FLOOD THREAT ON THU-
FRI BEFORE DRIER AND COOLER CONDS RETURN BY LATE SAT AND SUN.
CLOUDS/PCPN SHOULD OFFSET WARMING ALOFT AND KEEP TEMPS NEAR TO
SLIGHTLY BELOW AVG. MDL DATA INDICATES THE COLD FRONT WILL BECOME
MUCH LESS PROGRESSIVE OR STALL OUT OVER THE UPPER OH VLY WED NGT
INTO THUR.
MODELS AND ENS MEANS CENTER AROUND THE GENERAL IDEA OF A
MODERATELY SLOW PROGRESSION OF THE CLOSED LOW TRACKING EWD BTWN
THE GRT LKS AND HUDSON BAY FROM THU THRU SAT. AT THE SFC...THE
COLD FRONT TURN Q-STNRY BNDRY IN THE OH VLY...WHICH WAS ASSOCIATED
WITH THE LEAD SHORTWAVE TROUGH...SHOULD PUSH SLOWLY EWD ACRS CNTRL
PA ON DAY4/THU. THE SFC PATTERN GETS QUITE COMPLICATED FRI-SAT AS
WPC PROGS SHOW THE FIRST BOUNDARY STALLING OUT OVER THE SRN MID-
ATLC STATES AND SECONDARY COLD FRONT APPROACHING FROM THE GREAT
LAKES. WAVES OF LOW PRESSURE RIDING NEWD ALONG THESE ENCROACHING
FRONTS COULD KEEP UNSETTLED CONDS IN THE FCST THRU THE FIRST PART
OF THE WEEKEND.
ANOTHER PUSH OF WESTERLIES SHOULD OVERSPREAD THE AREA BY SUNDAY
AND NUDGE THE SECOND FRONT EWD TO OR OFF THE COAST. A LARGE AREA OF
CANADIAN HIGH PRESSURE SHOULD SUPPLY ANOTHER REFRESHINGLY COOL/DRY
AIRMASS INTO THE GREAT LAKES AND NORTHEAST BY NEXT SUNDAY. DON`T
EXPECT TEMPS TO FLUCTUATE VERY MUCH THRU THE MEDIUM
RANGE...CONTINUING TO AVG NEAR TO SLIGHTLY BELOW NORMAL FOR EARLY
AUGUST.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
SLY RETURN FLOW DEVELOPING ON THE WRN PERIPHERY OF HIGH PRES
SLIDING OFF THE EAST COAST WILL BRING INCREASING MSTR AND
THICKENING LOW-MID CLOUDS INTO CNTRL PA THRU TONIGHT. A LLVL MSTR
CONVERGENCE AXIS EXTENDING NWD FM THE SE STATES ALONG THE ERN
SLOPES OF THE APPLCHNS IS LKLY RESPONSIBLE FOR THE AREA OF 6-8KFT
CIGS OVER THE S-CNTRL AND SERN TAFS. EXPECT THESE CIGS TO THICKEN
AND LOWER 1-2KFT INTO THE MID MORNING AS BLYR COOLS AND LLVL FLOW
CONTINUES VEERING TO THE SOUTH-SOUTHEAST. THE INCREASINGLY MOIST
LLVL FLOW WILL OVERRUN A WARM FRONT LIFTING SLOWLY NEWD FROM THE
TN VLY AND CNTRL APPLCHNS AND SUPPORT SCT SHOWERS /WITH ISOLD
TSRA/ INTO THE AFTN. THE S-CNTRL AND SERN AIRFIELDS STAND THE
GREATEST CHC TO BE IMPACTED BY THE SHOWER ACTIVITY. EXPECT CIG
RESTRICTIONS TO BECOME MORE WIDESPREAD FROM TONIGHT INTO EARLY
WEDNESDAY AS SLY FLOW AND LLVL MSTR CONTINUES TO INCREASE AS WARM
FRONT LIFTS NEWD ACRS THE AIRSPACE.
OUTLOOK...
WED-FRI...MVFR/VFR. TWO FRONTAL SYSTEMS WILL BRING PERIODS OF
SHOWERS AND OCNL TSTMS.
SAT...BCMG VFR AS HIGH PRES BUILDS SEWD FROM THE UPPER MIDWEST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...DEVOIR/GARTNER
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1206 AM CDT TUE AUG 6 2013
.DISCUSSION...
SEE AVIATION FOR 06Z TAF ISSUANCE.
&&
.AVIATION...
MAINLY VFR CONDITIONS EXPECTED THROUGH THE ISSUANCE PERIOD. NAM
AND GFS DEWPOINT DEPRESSION FIELDS STILL HINTING AT LOWER
VISIBILITIES THIS MORNING MAINLY IN THE SOUTHWESTERN ZONES. MOST
LIKELY WILL BE LIMITED TO KLBX AND POSSIBLY KSGR. THIS AFTERNOON
SURFACE LOW PRESSURE WILL FORM IN THE TEXAS PANHANDLE CAUSING THE
PRESSURE GRADIENT TO SLIGHTLY STRENGTHEN KEEPING MODERATE WINDS IN
PLACE. RAP IS SHOWING A SEA AND BAY BREEZE MAKING ITS WAY INLAND
LATER THIS AFTERNOON. GIVEN CONTINUED MODERATE ONSHORE FLOW NOT
SOLD ON RAP SOLUTION. WIND SHIFT FROM SEA BREEZE WILL MOST LIKELY
BE TRANSIENT AS WAS THE CASE TODAY. 23
&&
.PREV DISCUSSION... /ISSUED 852 PM CDT MON AUG 5 2013/
UPDATE...
NO CHANGE TO THE ONGOING HEAT ADVISORY THAT WILL MOST LIKELY BE
IN EFFECT FOR ANOTHER FEW DAYS. THE CURRENT CONFIGURATION OF
COUNTIES IS ON POINT AS THESE WILL BE THE COUNTIES THAT EXPERIENCE
HEAT INDICES AT (OR GREATER THAN) 108 F...OR WHERE HIGHEST AMBIENT
TEMPERATURES WILL OCCUR IN TANDEM WITH HIGHER DEW POINT AIR.
ELSEWHERE...LOWER DEW POINT MIX-DOWN DURING PEAK HEATING WILL KEEP
HEAT INDICES BELOW DEFINED CRITERIA. THE MESSAGE OF HEAT SAFETY
REMAINS THE SAME IF YOU ARE OUTSIDE (NON-SHADED ENVIRONMENT) DURING
THE MID MORNING THROUGH EARLY EVENING HOURS...CORE BEING THAT OF
REMAINING HYDRATED WHILE KEEPING STRENUOUS ACTIVITY TO A MINIMUM.
31
PREV DISCUSSION... /ISSUED 604 PM CDT MON AUG 5 2013/
DISCUSSION...
SEE AVIATION FOR 00Z TAF ISSUANCE.
AVIATION...
MOSTLY VFR CONDITIONS EXPECTED THROUGH THE ISSUANCE PERIOD.
THERE IS ANOTHER CHANCE OF BRIEF MVFR CIGS TUESDAY MORNING AS
SOUNDINGS STILL SHOW AN INVERSION IN PLACE AROUND 900MB. THE
GREATEST CHANCE OF THIS WILL BE KCXO NORTHWARDS. IN THE
SOUTHWESTERN ZONES THERE IS ALSO A CHANCE OF SOME BRIEF MORNING
LOW VISIBILITIES. BOTH NAM AND GFS DEW POINT DEPRESSION FIELDS
SHOW THIS ALBEIT A TAD OVERDONE PROBABLY. 23
PREV DISCUSSION... /ISSUED 325 PM CDT MON AUG 5 2013/
DISCUSSION...
A VERY WARM AFTERNOON ACROSS SOUTHEAST TEXAS AS SOUTHWESTERLY LOW
LEVEL WINDS HAVE ALLOWED INLAND TEMPERATURES TO CLIMB INTO THE
UPPER 90S AND LOW 100S. TEMPERATURES ALONG THE COAST ARE ONLY IN
THE LOW TO MID 90S BUT RISING DEW POINTS BEHIND THE SEA BREEZE
HAVE PUSHED APPARENT TEMPERATURES ABOVE 105 DEGREES ALONG THE
COAST. THE HEAT ADVISORY HAS BEEN EXTENDED THROUGH TUESDAY
AFTERNOON FOR THE CURRENTLY AFFECTED AREA. AREAS FURTHER INLAND
HAVE MIXED OUT ENOUGH TO KEEP VALUES BELOW THE 108 DEGREE APPARENT
TEMPERATURE REQUIRED FOR ISSUANCE OF A HEAT ADVISORY.
NO RELIEF EXPECTED IN THE NEXT FEW DAYS AS TEMPERATURES WILL
REMAIN UNSEASONABLY WARM. STRONG SOUTHWESTERLY FLOW BELOW 700MB
WILL CONTINUE THROUGH MID WEEK WHICH WILL DRIVE TEMPERATURES INTO
THE TRIPLE DIGITS FOR MANY AREAS EACH AFTERNOON. PRECIPITATION
CHANCES REMAIN AT OR NEAR ZERO THROUGH THE MIDDLE OF THE WEEK AS
THE UPPER LEVEL RIDGE REMAINS FIRMLY PLANTED ACROSS THE STATE.
TEMPERATURES WILL BEGIN TO BACK DOWN JUST A BIT ON FRIDAY AS LOW
LEVEL MOISTURE BEGINS TO INCREASE IN ASSOCIATION WITH AN INVERTED
UPPER TROUGH WHICH WILL TREK WESTWARD ACROSS THE GULF OF MEXICO.
MODELS ARE NOW IN BETTER AGREEMENT WITH THIS FEATURE UNDERCUTTING
THE UPPER RIDGE ACROSS OUR AREA AND BRINGING INCREASED RAIN
CHANCES TO SOUTHEAST TEXAS FOR THIS WEEKEND. GIVEN THE INCREASE
IN MODEL AGREEMENT HAVE BUMPED POPS UP SLIGHTLY ON SATURDAY AND
SUNDAY OVER THE SOUTHERN HALF OF THE AREA. A RETURN TO DRIER AND
WARMER TEMPERATURES IS EXPECTED EARLY NEXT WEEK AS THE TROUGH
MOVES INTO MEXICO AND UPPER LEVEL RIDGING BECOMES REESTABLISHED
OVER THE REGION. 38
MARINE...
LIGHT TO MODERATE ONSHORE WINDS WILL PERSIST FOR MUCH OF THE WEEK
AND CONTINUE ON INTO THE WEEKEND. SPEEDS MIGHT REACH CAUTION LEVELS
TUESDAY AND TUESDAY NIGHT. AT THE VERY END OF THE WEEK AND OVER THE
WEEKEND...A WESTWARD MOVING TROPICAL WAVE IS EXPECTED TO BRING
INCREASING SHOWER AND THUNDERSTORM CHANCES TO THE AREA. 42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 101 78 102 79 102 / 10 10 10 0 0
HOUSTON (IAH) 98 77 100 79 100 / 10 10 10 0 0
GALVESTON (GLS) 93 81 94 82 94 / 10 10 10 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...HEAT ADVISORY UNTIL 9 PM CDT TUESDAY FOR THE FOLLOWING ZONES:
BRAZORIA...CHAMBERS...GALVESTON...HARRIS...JACKSON...
LIBERTY...MATAGORDA.
GM...NONE.
&&
$$
DISCUSSION...31
AVIATION/MARINE...23
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
358 AM CDT TUE AUG 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CDT TUE AUG 6 2013
AT 3 AM...DENSE FOG WAS REPORTED ACROSS MUCH OF SOUTHEAST
MINNESOTA...NORTHEAST IOWA...IN THE WISCONSIN RIVER VALLEY...
AND ON THE RIDGE TOPS SURROUNDING THE MISSISSIPPI RIVER. THE
VISIBILITIES AT OUR OFFICE IS LESS THAN A QUARTER MILE. AS A TROUGH
MOVES THROUGH NORTHEAST IOWA AND WESTERN WISCONSIN EARLY THIS
MORNING...THE WINDS WILL INCREASE ALOFT AND SOME DRIER AIR WILL
HELP DISSIPATE THE FOG BETWEEN 06.10Z AND 06.14Z.
FOR THIS AFTERNOON AND TONIGHT...WE WILL HAVE TO WATCH 2 AREAS OF
CONVECTION WHICH IS LOCATED CURRENTLY OVER THE DAKOTAS. THE LATEST
RAP SHOWS THAT 850 MB MOISTURE TRANSPORT INTO THESE AREAS WILL
KEEP THIS CONVECTION GOING THROUGH THE MORNING. THESE AREAS ARE
CAUSING HAVOC ON THE MESO MODELS. BOTH THE 06.00Z NMM AND ARW ARE
SHOWING THAT THE CONVECTION OVER NORTH DAKOTA IS THE MOST DOMINANT
AND THEY BRING A ROBUST AREA OF SHOWERS AND THUNDERSTORMS INTO
SOUTHEAST MINNESOTA AND NORTHEAST IOWA. MEANWHILE THE HRRR SHOW
THAT THE CONVECTION ACROSS NORTH DAKOTA WILL MOVE EAST SOUTHEAST
ACROSS NORTHERN MINNESOTA. MEANWHILE THE CONVECTION ACROSS WESTERN
SOUTH DAKOTA WILL DEVELOP A MESOSCALE VORTICITY WILL DEVELOP OUT
OF THIS THUNDERSTORM COMPLEX. LOOKING AT THE LATEST WATER VAPOR
AND RADAR IMAGERY THIS ACTUALLY MAKES A LOT OF SENSE. AS THIS
VORTICITY ENCOUNTERS INCREASING CAPES ACROSS EASTERN SOUTH
DAKOTA...NORTHWEST IOWA...AND SOUTHWEST MINNESOTA...THERE WILL BE
THE REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS LATE THIS MORNING
AND AFTERNOON. ADDITIONAL LINES OF THUNDERSTORMS WILL LIKELY
DEVELOP AHEAD OF AN APPROACHING COLD FRONT ACROSS WEST CENTRAL
AND NORTHWEST MINNESOTA. THERE IS MORE THAN ADEQUATE SHEAR FOR THESE
THUNDERSTORMS TO BECOME ORGANIZED. THIS WILL INCLUDE SPLITTING
SUPERCELLS AND BOWING LINE SEGMENTS. THE MAIN SEVERE WEATHER
THREAT ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND WEST
CENTRAL AND SOUTHWEST WISCONSIN WILL BE LIKELY LARGE HAIL...DAMAGING
WINDS...AND POSSIBLY ISOLATED TORNADOES FROM 6 PM THROUGH MIDNIGHT.
AS THE COLD FRONT SWEEPS THROUGH THE AREA OVERNIGHT...THE THREAT
FOR SHOWERS AND THUNDERSTORMS WILL QUICKLY COME TO AN END ACROSS
THE AREA FROM NORTHWEST TO SOUTHEAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM CDT TUE AUG 6 2013
ON THURSDAY NIGHT AND FRIDAY...THE 06.00Z MODELS ARE IN GOOD
AGREEMENT THAT A VIGOROUS SHORT WAVE TROUGH WILL MOVE EAST ACROSS
NORTHERN MINNESOTA AND UPPER MICHIGAN. AS THIS OCCURS...A COLD
FRONT WILL MOVE SOUTH THROUGH THE NORTHERN HALVES OF MINNESOTA AND
WISCONSIN. THERE LOOKS TO BE ENOUGH INSTABILITY AND SYNOPTIC
FORCING FOR THE DEVELOPMENT OF SCATTERED SHOWERS AND
THUNDERSTORMS ALONG AND AHEAD OF THIS FRONT. WITH THE BEST 0-6 KM
SHEAR IN THE WAKE OF THIS SYSTEM...NOT EXPECTING TO SEE ANY SEVERE
WEATHER FROM THIS SYSTEM.
FROM LATE SATURDAY NIGHT INTO MONDAY...THE MODELS CONTINUE TO
STRUGGLE WITH THE LOCATION AND TIMING OF SHORT WAVES MOVING
OUT OF THE NORTHERN PLAINS. AS A RESULT CONFIDENCE IN THE TIMING
AND LOCATION OF PRECIPITATION DURING THIS TIME PERIOD IS LOWER
THAN NORMAL. AS A RESULT...JUST WENT WITH THE ALL BLEND FOR THIS
TIME PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1124 PM CDT MON AUG 5 2013
CONDITIONS CONTINUE TO DETERIORATE ACROSS THE REGION AS A LOW END
MVFR TO IFR STRATUS DECK STALLED ALONG AND EAST OF THE MISSISSIPPI
RIVER. FURTHER WEST OF THIS STRATUS IN SOUTHEAST MINNESOTA AND
NORTHEAST IOWA...SKIES HAVE CLEARED WITH FOG FORMING DUE TO THE
LIGHT WINDS AND RECENT RAINS. EXPECT THAT CONDITIONS WILL CONTINUE
TO DROP THROUGH THE NIGHT WITH VISIBILITY DROPPING TO A QUARTER OF
A MILE AT TIMES...THOUGH LSE HAS BEEN AT 10SM ALL EVENING DESPITE
HAVING A 1KFT DECK OVERHEAD. WARMER AIR WILL MOVE IN TOMORROW
MORNING AND WILL HELP TO IMPROVE CONDITIONS RATHER QUICKLY.
SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED TO DEVELOP AHEAD OF A
COLD FRONT TUESDAY AFTERNOON/EVENING ACROSS MINNESOTA. SOME BRIEF
DROPS TO IFR WILL BE POSSIBLE AS THESE STORMS ROLL THROUGH
SOMETIME IN THE LATE AFTERNOON AND EARLY EVENING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ086-087-
094-095.
IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ008>010-
018-019-029.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
120 AM CDT TUE AUG 6 2013
.UPDATE...
ISSUED AT 120 AM CDT TUE AUG 6 2013
FOG CONTINUED TO THICKEN ACROSS AREAS WEST OF THE MISSISSIPPI RIVER
EARLY THIS MORNING...PER SFC OBS WITH SUPPORT FROM CALLS TO LOCAL
DISPATCHES...SO HAVE ISSUED A DENSE FOG ADV THROUGH 14Z. THE FOG MAY
CLEAR A FEW HOURS BEFORE THAT THOUGH AS A WEAK SFC TROUGH MOVES IN.
WILL KEEP AN EYE ON TRENDS AND CLEAR THE ADV EARLY IF NEEDED.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 310 PM CDT MON AUG 5 2013
THE NEXT 24 TO 36 HOURS WILL FEATURE A MORE ACTIVE PERIOD WITH A
FEW WEATHER SYSTEMS TO CONTEND WITH INCLUDING PRECIPITATION
CHANCES THIS EVENING...FOG OVERNIGHT...AND THEN SEVERE THREAT
TUESDAY AFTERNOON/EVENING.
LATEST WATER VAPOR COMBINED WITH RAP 500MB HEIGHTS SHOW BROAD
NORTHWEST FLOW EAST OF THE ROCKIES...WITH NUMEROUS EMBEDDED
SHORTWAVE TROUGHS. ONE CURRENTLY MOVING THROUGH
MINNESOTA/IOWA...WHILE UPSTREAM ACROSS ALBERTA SITS A MORE VIGOROUS
WAVE. FINALLY...A CLOSED POLAR VORTEX RESIDES NEAR HUDSON BAY.
FOR THIS EVENING INTO TONIGHT...WILL CARRY A SLIGHT CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS UNTIL UPPER LEVEL SHORTWAVE
COMPLETELY EXITS THE AREA. DESPITE SURFACE TROUGH LAGGING
BEHIND...AND BUILDING INSTABILITY WITH CLEARING SKIES...SUBSIDENCE
IN THE WAKE OF THE UPPER LEVEL SHORTWAVE AND SOME LOW TO MID LEVEL
DRYING SHOULD PRECLUDE THE DEVELOPMENT OF ADDITIONAL SHOWERS/STORMS.
HAVE ADDED PATCHY TO AREAS OF FOG FOR PARTS OF WISCONSIN...INCLUDING
THE MS AND WISCONSIN RIVER VALLEYS OVERNIGHT AS A WEAK SURFACE
HIGH BUILDS IN THE WAKE OF THE DEPARTING SYSTEM AND AHEAD OF THE
APPROACHING COLD FRONT. NICE SETUP WITH TODAY/S COOL...CLOUDY
CONDITIONS AND RECENT RAINFALL...THEN CLEARING SKIES LATE THIS
EVENING. SURFACE WIND FIELD DROPS TO 5 KTS OR LESS...AND SOUNDINGS
SHOW DECENT BOUNDARY LAYER SATURATION THOUGH TRY TO SHOW A STIFF
BREEZE AT ABOUT 500 FT. COULD BE A MORE WIDESPREAD FOG SCENARIO
INSTEAD OF JUST THE RIVER VALLEYS...SOMETHING TO WATCH THIS
EVENING.
THE ALBERTA SHORTWAVE TROUGH THEN TAKES AIM ON THE AREA...AND WILL
BE THE FOCUS FOR PUSHING THROUGH A SURFACE COLD FRONT TUESDAY
EVENING. BUILDING INSTABILITY DURING THE DAY IS SOMEWHAT CONDITIONAL
ON AN EARLY MORNING MCS EXPECTED WELL TO OUR WEST...BUT BY MID
AFTERNOON...MUCAPE BETWEEN 1500 AND 2000 J/KG COULD BE REALIZED. THE
SHEAR ENVIRONMENT IS MORE THAN SUFFICIENT FOR SEVERE STORMS AS 250
MB JET MAX OVERHEAD PUTS 40 TO 50 KTS OF EFFECTIVE SHEAR ACROSS MUCH
OF THE AREA...AND THE LOW-LEVELS HAVE FAVORABLE LAPSE RATES.
HODOGRAPHS SHOW MODEST LOOPING. OVERALL...IF INSTABILITY CONDITIONS
ARE MET...ENVISION STORM MODE TO FAVOR RIGHT MOVING CLUSTER OF
CELLS EVOLVING INTO BOWING SEGMENTS WITH THE MAIN THREAT LARGE
HAIL AND DAMAGING WINDS. 0-1 KM SHEAR ENVIRONMENT IS
UNIDIRECTIONAL SO NOT EXPECTING A FAVORABLE TORNADO ENVIRONMENT
HOWEVER WITH THAT SAID...ANY LINGERING SURFACE BOUNDARIES COULD
COMPLICATE THAT.
MODEL AGREEMENT ON FRONTAL TIMING IS HIGHER WITH THE 05.12Z
GUIDANCE...WHICH ADDS CONFIDENCE TO THE LATE AFTERNOON AND EVENING
PRECIPITATION CHANCES. THE NAM REMAINS A FASTER OUTLIER WHILE THE
GEM/GFS/ECMWF ARE CONSISTENT WITH A 00 TO 06Z PASSAGE. EARLIER
FORECAST TIMING FOR POPS LOOK GOOD SO HAVE CARRIED SIMILAR
THINKING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 310 PM CDT MON AUG 5 2013
THE BIG STORY IN THE LONG TERM WILL BE A CONTINUATION OF THE
UNSEASONABLY COOL WEATHER PATTERN AS THE MAIN POLAR VORTEX / CLOSED
UPPER LOW WOBBLES ACROSS SOUTHERN CANADA. OUTSIDE OF SCATTERED
DAYTIME CUMULUS FIELD ACROSS WISCONSIN WEDNESDAY...HIGH PRESSURE
DOMINATES WITH PLEASANT CONDITIONS. HIGHS LOWER TO MIDDLE 70S.
ANOTHER SIMILAR DAY THURSDAY...THOUGH BY EVENING INTO THE NIGHT THE
CLOSED UPPER LOW WOBBLES FURTHER TO THE SOUTH AS ANOTHER PIECE OF
ENERGY ROUNDS THE BASE. THIS TRIES TO DRIVE A SURFACE COLD FRONT
WITH SHOWERS AND THUNDERSTORMS ACROSS CENTRAL MINNESOTA INTO
WISCONSIN. HOWEVER...BETTER DYNAMICS AND MOISTURE TRANSPORT REMAIN
IN THE WEST AND NORTH FORECAST...AND THE FRONT WASHES OUT BEFORE
MAKING IT VERY FAR INTO THE FORECAST AREA. WILL CONTINUE SLIGHT
CHANCES IN THE NORTHWEST WHILE THE REST OF THE AREA WILL LIKELY ONLY
SEE INCREASED CLOUD COVER.
IN THE WAKE OF THIS SHORTWAVE TROUGH...A REINFORCING SHOT OF COOLER
AIR SURGES IN AS SEEN BY 850 MB TEMPERATURES FRIDAY AND SATURDAY
DROPPING TO THE 8 TO 10C RANGE. HIGHS IN THE 70S AND OVERNIGHT LOWS
COULD DIP INTO THE UPPER 40S TO LOWER 50S...ESPECIALLY FOR THE
TYPICAL COOLER SPOTS OF CENTRAL WISCONSIN. DEPENDING ON THE HIGH
PRESSURE AXIS...COULD SEE A FEW MORNINGS OF RIVER VALLEY FOG AS
WELL. OVERALL...VERY NICE CONDITIONS FOR EARLY/MID AUGUST POSSIBLE
ACROSS THE ENTIRE UPPER MIDWEST FROM FRIDAY INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1124 PM CDT MON AUG 5 2013
CONDITIONS CONTINUE TO DETERIORATE ACROSS THE REGION AS A LOW END
MVFR TO IFR STRATUS DECK STALLED ALONG AND EAST OF THE MISSISSIPPI
RIVER. FURTHER WEST OF THIS STRATUS IN SOUTHEAST MINNESOTA AND
NORTHEAST IOWA...SKIES HAVE CLEARED WITH FOG FORMING DUE TO THE
LIGHT WINDS AND RECENT RAINS. EXPECT THAT CONDITIONS WILL CONTINUE
TO DROP THROUGH THE NIGHT WITH VISIBILITY DROPPING TO A QUARTER OF
A MILE AT TIMES...THOUGH LSE HAS BEEN AT 10SM ALL EVENING DESPITE
HAVING A 1KFT DECK OVERHEAD. WARMER AIR WILL MOVE IN TOMORROW
MORNING AND WILL HELP TO IMPROVE CONDITIONS RATHER QUICKLY.
SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED TO DEVELOP AHEAD OF A
COLD FRONT TUESDAY AFTERNOON/EVENING ACROSS MINNESOTA. SOME BRIEF
DROPS TO IFR WILL BE POSSIBLE AS THESE STORMS ROLL THROUGH
SOMETIME IN THE LATE AFTERNOON AND EARLY EVENING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ086-087-
094-095.
IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ008>010-
018-019-029.
&&
$$
UPDATE.......RIECK
SHORT TERM...ZT
LONG TERM....ZT
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1124 PM CDT MON AUG 5 2013
.UPDATE...
ISSUED AT 912 PM CDT MON AUG 5 2013
DIURNAL CONVECTION HAS GENERALLY COME TO AN END ACROSS THE REGION
WITH SOME TRAILING SHOWERS LINGERING IN SOUTHWEST WISCONSIN ALONG
A WEAK SURFACE TROUGH/COLD FRONT. MID LEVEL SUBSIDENCE NOTED ON
WATER VAPOR HAS ALLOWED FOR SKIES TO CLEAR OUT ACROSS MUCH OF
MINNESOTA AND IOWA. IT WAS LOOKING LIKE WISCONSIN WOULD GET IN ON
THE CLEARING AS WELL...BUT A LOW LEVEL STRATUS DECK GOT STUCK
UNDER A SHALLOW INVERSION AROUND 1500FT AND HAS STALLED OUT FROM
FAR EASTERN MINNESOTA/IOWA ON INTO WESTERN WISCONSIN. WITH THE LOW
LEVEL SURGE OF DRIER AIR APPEARING TO HAVE STALLED OUT TO THE
WEST...AM BECOMING MORE CONCERNED FOR THE POTENTIAL OF DENSE FOG
TONIGHT. THE MAIN UNCERTAINTY IS WITH WHETHER THIS WILL JUST STAY
AS A LOW LEVEL STRATUS DECK BECAUSE OF SOME
STRONGER...10KT...WINDS AT THE INVERSION LEVEL OR IF THE
SATURATION WILL JUST CONTINUE ON DOWN TO THE GROUND OVERNIGHT.
SOME REPORTS FROM NORTHEAST IOWA HAVE BEEN THAT VISIBILITY HAS
DROPPED DOWN TO AN EIGHTH OF A MILE IN SPOTS IN EASTERN FILLMORE
COUNTY AND NORTHERN WINNESHIEK COUNTIES. WITH SUCH HIGH MOISTURE
ALREADY IN PLACE...AM LEANING MORE ALONG THE FOG SOLUTION RATHER
THAN JUST STRATUS. IF QUARTER MILE VISIBILITIES BECOME MORE
WIDESPREAD...MAY HAVE TO DO A DENSE FOG ADVISORY OVERNIGHT.
ALSO...DESPITE LOW LEVEL FORCING LOOKING WEAK...ALSO CAN NOT RULE
OUT SOME DRIZZLE WITH THESE LOW CEILINGS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 310 PM CDT MON AUG 5 2013
THE NEXT 24 TO 36 HOURS WILL FEATURE A MORE ACTIVE PERIOD WITH A
FEW WEATHER SYSTEMS TO CONTEND WITH INCLUDING PRECIPITATION
CHANCES THIS EVENING...FOG OVERNIGHT...AND THEN SEVERE THREAT
TUESDAY AFTERNOON/EVENING.
LATEST WATER VAPOR COMBINED WITH RAP 500MB HEIGHTS SHOW BROAD
NORTHWEST FLOW EAST OF THE ROCKIES...WITH NUMEROUS EMBEDDED
SHORTWAVE TROUGHS. ONE CURRENTLY MOVING THROUGH
MINNESOTA/IOWA...WHILE UPSTREAM ACROSS ALBERTA SITS A MORE VIGOROUS
WAVE. FINALLY...A CLOSED POLAR VORTEX RESIDES NEAR HUDSON BAY.
FOR THIS EVENING INTO TONIGHT...WILL CARRY A SLIGHT CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS UNTIL UPPER LEVEL SHORTWAVE
COMPLETELY EXITS THE AREA. DESPITE SURFACE TROUGH LAGGING
BEHIND...AND BUILDING INSTABILITY WITH CLEARING SKIES...SUBSIDENCE
IN THE WAKE OF THE UPPER LEVEL SHORTWAVE AND SOME LOW TO MID LEVEL
DRYING SHOULD PRECLUDE THE DEVELOPMENT OF ADDITIONAL SHOWERS/STORMS.
HAVE ADDED PATCHY TO AREAS OF FOG FOR PARTS OF WISCONSIN...INCLUDING
THE MS AND WISCONSIN RIVER VALLEYS OVERNIGHT AS A WEAK SURFACE
HIGH BUILDS IN THE WAKE OF THE DEPARTING SYSTEM AND AHEAD OF THE
APPROACHING COLD FRONT. NICE SETUP WITH TODAY/S COOL...CLOUDY
CONDITIONS AND RECENT RAINFALL...THEN CLEARING SKIES LATE THIS
EVENING. SURFACE WIND FIELD DROPS TO 5 KTS OR LESS...AND SOUNDINGS
SHOW DECENT BOUNDARY LAYER SATURATION THOUGH TRY TO SHOW A STIFF
BREEZE AT ABOUT 500 FT. COULD BE A MORE WIDESPREAD FOG SCENARIO
INSTEAD OF JUST THE RIVER VALLEYS...SOMETHING TO WATCH THIS
EVENING.
THE ALBERTA SHORTWAVE TROUGH THEN TAKES AIM ON THE AREA...AND WILL
BE THE FOCUS FOR PUSHING THROUGH A SURFACE COLD FRONT TUESDAY
EVENING. BUILDING INSTABILITY DURING THE DAY IS SOMEWHAT CONDITIONAL
ON AN EARLY MORNING MCS EXPECTED WELL TO OUR WEST...BUT BY MID
AFTERNOON...MUCAPE BETWEEN 1500 AND 2000 J/KG COULD BE REALIZED. THE
SHEAR ENVIRONMENT IS MORE THAN SUFFICIENT FOR SEVERE STORMS AS 250
MB JET MAX OVERHEAD PUTS 40 TO 50 KTS OF EFFECTIVE SHEAR ACROSS MUCH
OF THE AREA...AND THE LOW-LEVELS HAVE FAVORABLE LAPSE RATES.
HODOGRAPHS SHOW MODEST LOOPING. OVERALL...IF INSTABILITY CONDITIONS
ARE MET...ENVISION STORM MODE TO FAVOR RIGHT MOVING CLUSTER OF
CELLS EVOLVING INTO BOWING SEGMENTS WITH THE MAIN THREAT LARGE
HAIL AND DAMAGING WINDS. 0-1 KM SHEAR ENVIRONMENT IS
UNIDIRECTIONAL SO NOT EXPECTING A FAVORABLE TORNADO ENVIRONMENT
HOWEVER WITH THAT SAID...ANY LINGERING SURFACE BOUNDARIES COULD
COMPLICATE THAT.
MODEL AGREEMENT ON FRONTAL TIMING IS HIGHER WITH THE 05.12Z
GUIDANCE...WHICH ADDS CONFIDENCE TO THE LATE AFTERNOON AND EVENING
PRECIPITATION CHANCES. THE NAM REMAINS A FASTER OUTLIER WHILE THE
GEM/GFS/ECMWF ARE CONSISTENT WITH A 00 TO 06Z PASSAGE. EARLIER
FORECAST TIMING FOR POPS LOOK GOOD SO HAVE CARRIED SIMILAR
THINKING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 310 PM CDT MON AUG 5 2013
THE BIG STORY IN THE LONG TERM WILL BE A CONTINUATION OF THE
UNSEASONABLY COOL WEATHER PATTERN AS THE MAIN POLAR VORTEX / CLOSED
UPPER LOW WOBBLES ACROSS SOUTHERN CANADA. OUTSIDE OF SCATTERED
DAYTIME CUMULUS FIELD ACROSS WISCONSIN WEDNESDAY...HIGH PRESSURE
DOMINATES WITH PLEASANT CONDITIONS. HIGHS LOWER TO MIDDLE 70S.
ANOTHER SIMILAR DAY THURSDAY...THOUGH BY EVENING INTO THE NIGHT THE
CLOSED UPPER LOW WOBBLES FURTHER TO THE SOUTH AS ANOTHER PIECE OF
ENERGY ROUNDS THE BASE. THIS TRIES TO DRIVE A SURFACE COLD FRONT
WITH SHOWERS AND THUNDERSTORMS ACROSS CENTRAL MINNESOTA INTO
WISCONSIN. HOWEVER...BETTER DYNAMICS AND MOISTURE TRANSPORT REMAIN
IN THE WEST AND NORTH FORECAST...AND THE FRONT WASHES OUT BEFORE
MAKING IT VERY FAR INTO THE FORECAST AREA. WILL CONTINUE SLIGHT
CHANCES IN THE NORTHWEST WHILE THE REST OF THE AREA WILL LIKELY ONLY
SEE INCREASED CLOUD COVER.
IN THE WAKE OF THIS SHORTWAVE TROUGH...A REINFORCING SHOT OF COOLER
AIR SURGES IN AS SEEN BY 850 MB TEMPERATURES FRIDAY AND SATURDAY
DROPPING TO THE 8 TO 10C RANGE. HIGHS IN THE 70S AND OVERNIGHT LOWS
COULD DIP INTO THE UPPER 40S TO LOWER 50S...ESPECIALLY FOR THE
TYPICAL COOLER SPOTS OF CENTRAL WISCONSIN. DEPENDING ON THE HIGH
PRESSURE AXIS...COULD SEE A FEW MORNINGS OF RIVER VALLEY FOG AS
WELL. OVERALL...VERY NICE CONDITIONS FOR EARLY/MID AUGUST POSSIBLE
ACROSS THE ENTIRE UPPER MIDWEST FROM FRIDAY INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1124 PM CDT MON AUG 5 2013
CONDITIONS CONTINUE TO DETERIORATE ACROSS THE REGION AS A LOW END
MVFR TO IFR STRATUS DECK STALLED ALONG AND EAST OF THE MISSISSIPPI
RIVER. FURTHER WEST OF THIS STRATUS IN SOUTHEAST MINNESOTA AND
NORTHEAST IOWA...SKIES HAVE CLEARED WITH FOG FORMING DUE TO THE
LIGHT WINDS AND RECENT RAINS. EXPECT THAT CONDITIONS WILL CONTINUE
TO DROP THROUGH THE NIGHT WITH VISIBILITY DROPPING TO A QUARTER OF
A MILE AT TIMES...THOUGH LSE HAS BEEN AT 10SM ALL EVENING DESPITE
HAVING A 1KFT DECK OVERHEAD. WARMER AIR WILL MOVE IN TOMORROW
MORNING AND WILL HELP TO IMPROVE CONDITIONS RATHER QUICKLY.
SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED TO DEVELOP AHEAD OF A
COLD FRONT TUESDAY AFTERNOON/EVENING ACROSS MINNESOTA. SOME BRIEF
DROPS TO IFR WILL BE POSSIBLE AS THESE STORMS ROLL THROUGH
SOMETIME IN THE LATE AFTERNOON AND EARLY EVENING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...ZT
LONG TERM....ZT
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
913 AM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURFACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTION ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCED
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVECTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPAGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE SCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
WHILE THE CONVECTION IS LIKELY TO BE ON A WEAKENING TREND INTO
WEDNESDAY MORNING...IF NOT ALREADY OVERNIGHT...GUIDANCE HAS AGREED
ON A SLOWER MOVEMENT OF THE FRONT IN THE PAST 24 HOURS. SO HAVE
INCREASED POPS IN EASTERN AREAS DURING EARLY WEDNESDAY.
CONFIDENCE...MEDIUM.
WEDNESDAY AFTERNOON THROUGH FRIDAY...AS THE FRONT EASES IN SPEED
THERE IS CONCERN FOR CONVECTION IN THE SOUTHEAST PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON. HIGH MOISTURE WILL STILL OWE TO
MODEST TO HIGH INSTABILITY ALONG THE BOUNDARY. EVEN A SLOWER
FRONTAL MOVEMENT MAY MEAN WE COULD HAVE A SEVERE WEATHER THREAT IN
THE FAR SOUTHERN FORECAST AREA. FOR THE TIME BEING MAINTAIN THE
CHANCE POPS IN THE SOUTHERN AREA.
LARGER INCREASES IN POPS WERE MADE FOR THU NIGHT AND INTO FRI
ACROSS THE SOUTHEAST HALF OF THE FORECAST AS ONE AND POSSIBLY
MULTIPLE WAVES TRAVERSE THE BOUNDARY...SPREADING SOUTHERLY 850MB
FLOW NORTH OF THE FEATURE POTENTIALLY LEADING TO SOME SHOWERS AND
STORMS ACROSS OUR AREA...DESPITE NORTHERLY SURFACE FLOW. THE MAIN
FOCUS FOR ANYTHING OF HIGH IMPACT STILL LOOKS TO BE WELL SOUTH OF
THE AREA. FOR TEMPERATURES ON WED-FRI HAVE GONE JUST A COUPLE
DEGREES ABOVE AN OFFICIAL/MODEL BLEND.
THIS WEEKEND...LITTLE CHANGES MADE TO THE GOING FORECAST AS HIGH
PRESSURE IS STILL FAVORED IN THAT TIME YIELDING LIKELY PLEASANT
WEATHER. GUIDANCE MAY BE A LITTLE QUICK ON BRINGING PRECIP
CHANCES BACK SUNDAY NIGHT...BUT FOR THE TIME BEING HAVE GONE WITH
A BLEND DUE TO ATTENTION ON THE SHORT TERM.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* CIG AND VIS TRENDS WITH LOW MVFR/IFR CIGS DOWN IN THE 800-1000
FEET LEVEL THIS MORNING.
* TIMING THE IMPROVEMENT OF CIGS DURING THE MID TO LATE MORNING
HOURS. IMPROVEMENT MIGHT BE A LITTLE LATER THAN TAF
INDICATES...BUT WHEN IMPROVEMENT COMES...SHOULD BE QUICK.
* CHANCE OF TSRA TONIGHT.
KREIN
//DISCUSSION...UPDATED 12Z...
THERE ARE A FEW LINGERING SHOWERS LEFT OVER FROM THE OVERNIGHT
STORMS ACROSS NORTH CENTRAL ILLINOIS. HOWEVER...THE PRIMARY FORECAST
CONCERNS IN THE NEAR TERM WILL BE CIGS AND VIS TRENDS THIS
MORNING. ATTENTION THEN TURNS TO LATER TONIGHT INTO WEDNESDAY
MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A MESSY
MORNING ACROSS THE AREA. CIGS AND VIS ARE TANKING IN THE WAKE OF
THE HIGHER CLOUD COVER AND AREA OF SHOWERS. MOST AREAS WEST OF THE
CHICAGO AREA ARE UNDER 800 FEET WITH VIS NOW DOWN TO 1/2 SM AT
KRFD. I EXPECT THESE DETERIORATING CONDITIONS TO CONTINUE TO
OVERSPREAD THE EASTERN TAF SITES EARLY THIS MORNING. I SUSPECT
THAT THE VIS WILL DROP AT KORD AND KMDW AS WELL FOR A PERIOD EARLY
THIS MORNING...BUT CONFIDENCE ON HOW LOW THEY WILL DROP IS
LOW...BUT MVFR VIS AROUND 5 SM IS CERTAINLY POSSIBLE GIVEN THE
TRENDS TO THE WEST. SO BY FAR THE BIGGEST DEAL WILL BE THE LOW CIGS.
CIGS WILL PROB BE A BIT SLOW TO RECOVER THIS MORNING...WITH NO BIG
IMPROVEMENTS UNTIL AFTER 14-15 UTC THIS MORNING. HOWEVER...ONCE
THINGS IMPROVE LATER THIS MORNING...AVIATION WEATHER CONCERNS
SHOULD BE AT A MINIMUM THROUGH THE REST OF THE DAY.
IT APPEARS LIKELY THAT A COMPLEX OF THUNDERSTORMS WILL DEVELOP
WEST OF THE AREA ACROSS IOWA AND SOUTHWESTERN WISCONSIN DURING THE
EVENING TODAY. THIS ACTIVITY APPEARS THAT IT WILL MOVE OVER
NORTHERN ILLINOIS LATER TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY
AT THE EASTERN TAF SITS. IT MAY BE IN A WEAKENING STATE AS IT
ARRIVES ACROSS NORTHEASTERN ILLINOIS...BUT I DID CONTINUE THE
MENTION OF SHRA AND VCTS ALL THE TAFS AFTER 06 UTC TONIGHT. IT IS
POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW HOURS PRIOR
TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE TONIGHT
INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE APPROACHES
THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN THE AIR MASS
AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* LOW CONFIDENCE IN TIMING OF IMPROVEMENT OF THE LOW MVFR/IFR
CIGS THIS MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TUESDAY
NIGHT...WITH ONLY LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY
SOUTH OF CHICAGO THURSDAY NIGHT.
MONDAY...SLIGHT CHANCE OF TSRA.
KJB
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
648 AM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURFACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTION ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCED
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVECTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPAGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE SCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
WHILE THE CONVECTION IS LIKELY TO BE ON A WEAKENING TREND INTO
WEDNESDAY MORNING...IF NOT ALREADY OVERNIGHT...GUIDANCE HAS AGREED
ON A SLOWER MOVEMENT OF THE FRONT IN THE PAST 24 HOURS. SO HAVE
INCREASED POPS IN EASTERN AREAS DURING EARLY WEDNESDAY.
CONFIDENCE...MEDIUM.
WEDNESDAY AFTERNOON THROUGH FRIDAY...AS THE FRONT EASES IN SPEED
THERE IS CONCERN FOR CONVECTION IN THE SOUTHEAST PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON. HIGH MOISTURE WILL STILL OWE TO
MODEST TO HIGH INSTABILITY ALONG THE BOUNDARY. EVEN A SLOWER
FRONTAL MOVEMENT MAY MEAN WE COULD HAVE A SEVERE WEATHER THREAT IN
THE FAR SOUTHERN FORECAST AREA. FOR THE TIME BEING MAINTAIN THE
CHANCE POPS IN THE SOUTHERN AREA.
LARGER INCREASES IN POPS WERE MADE FOR THU NIGHT AND INTO FRI
ACROSS THE SOUTHEAST HALF OF THE FORECAST AS ONE AND POSSIBLY
MULTIPLE WAVES TRAVERSE THE BOUNDARY...SPREADING SOUTHERLY 850MB
FLOW NORTH OF THE FEATURE POTENTIALLY LEADING TO SOME SHOWERS AND
STORMS ACROSS OUR AREA...DESPITE NORTHERLY SURFACE FLOW. THE MAIN
FOCUS FOR ANYTHING OF HIGH IMPACT STILL LOOKS TO BE WELL SOUTH OF
THE AREA. FOR TEMPERATURES ON WED-FRI HAVE GONE JUST A COUPLE
DEGREES ABOVE AN OFFICIAL/MODEL BLEND.
THIS WEEKEND...LITTLE CHANGES MADE TO THE GOING FORECAST AS HIGH
PRESSURE IS STILL FAVORED IN THAT TIME YIELDING LIKELY PLEASANT
WEATHER. GUIDANCE MAY BE A LITTLE QUICK ON BRINGING PRECIP
CHANCES BACK SUNDAY NIGHT...BUT FOR THE TIME BEING HAVE GONE WITH
A BLEND DUE TO ATTENTION ON THE SHORT TERM.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* CIG AND VIS TRENDS WITH LOW MVFR/IFR CIGS DOWN IN THE 700-1000
FEET LEVEL EARLY THIS MORNING.
* TIMING THE IMPROVEMENT OF THESE LOWER CIGS DURING THE MID TO
LATE MORNING HOURS. BIG IMPROVEMENTS NOT LIKELY UNTIL AFTER
14-15 UTC.
* GOOD CHANCE OF TSRA TUESDAY NIGHT.
KJB
//DISCUSSION...UPDATED 12Z...
THERE ARE A FEW LINGERING SHOWERS LEFT OVER FROM THE OVERNIGHT
STORMS ACROSS NORTH CENTRAL ILLINOIS. HOWEVER...THE PRIMARY FORECAST
CONCERNS IN THE NEAR TERM WILL BE CIGS AND VIS TRENDS THIS
MORNING. ATTENTION THEN TURNS TO LATER TONIGHT INTO WEDNESDAY
MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A MESSY
MORNING ACROSS THE AREA. CIGS AND VIS ARE TANKING IN THE WAKE OF
THE HIGHER CLOUD COVER AND AREA OF SHOWERS. MOST AREAS WEST OF THE
CHICAGO AREA ARE UNDER 800 FEET WITH VIS NOW DOWN TO 1/2 SM AT
KRFD. I EXPECT THESE DETERIORATING CONDITIONS TO CONTINUE TO
OVERSPREAD THE EASTERN TAF SITES EARLY THIS MORNING. I SUSPECT
THAT THE VIS WILL DROP AT KORD AND KMDW AS WELL FOR A PERIOD EARLY
THIS MORNING...BUT CONFIDENCE ON HOW LOW THEY WILL DROP IS
LOW...BUT MVFR VIS AROUND 5 SM IS CERTAINLY POSSIBLE GIVEN THE
TRENDS TO THE WEST. SO BY FAR THE BIGGEST DEAL WILL BE THE LOW CIGS.
CIGS WILL PROB BE A BIT SLOW TO RECOVER THIS MORNING...WITH NO BIG
IMPROVEMENTS UNTIL AFTER 14-15 UTC THIS MORNING. HOWEVER...ONCE
THINGS IMPROVE LATER THIS MORNING...AVIATION WEATHER CONCERNS
SHOULD BE AT A MINIMUM THROUGH THE REST OF THE DAY.
IT APPEARS LIKELY THAT A COMPLEX OF THUNDERSTORMS WILL DEVELOP
WEST OF THE AREA ACROSS IOWA AND SOUTHWESTERN WISCONSIN DURING THE
EVENING TODAY. THIS ACTIVITY APPEARS THAT IT WILL MOVE OVER
NORTHERN ILLINOIS LATER TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY
AT THE EASTERN TAF SITS. IT MAY BE IN A WEAKENING STATE AS IT
ARRIVES ACROSS NORTHEASTERN ILLINOIS...BUT I DID CONTINUE THE
MENTION OF SHRA AND VCTS ALL THE TAFS AFTER 06 UTC TONIGHT. IT IS
POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW HOURS PRIOR
TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE TONIGHT
INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE APPROACHES
THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN THE AIR MASS
AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN TIMING OF IMPROVEMENT OF THE LOW MVFR/IFR
CIG/VIS THIS MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TUESDAY
NIGHT...WITH ONLY LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY
SOUTH OF CHICAGO THURSDAY NIGHT.
MONDAY...SLIGHT CHANCE OF TSRA.
KJB
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1014 AM EDT TUE AUG 6 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 243 AM EDT TUE AUG 6 2013
WARMER AIR IS SET TO ARRIVE IN INDIANA TODAY AS HIGH PRESSURE OVER
THE EAST COAST PROVIDES A WARMER AND MORE HUMID SOUTHERLY FLOW
ALONG WITH DRY WEATHER. A MORE ACTIVE WEATHER PATTERN WILL TAKE
SHAPE THROUGH THE MIDDLE OF THE WEEK AS A COLD FRONT IS EXPECTED
TO PUSH TOWARD INDIANA LATE TONIGHT AND STALL ACROSS SOUTHERN
INDIANA THROUGH THURSDAY THE FRONT WILL BRING CHANCES FOR SHOWERS
AND STORMS FROM LATE TONIGHT THROUGH FRIDAY.
HIGH PRESSURE IS EXPECTED TO ARRIVE LATE FRIDAY AND BRING A RETURN
TO DRY WEATHER FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 944 AM EDT TUE AUG 6 2013
BUMPED UP CLOUD COVER THIS MORNING DUE TO SATELLITE TRENDS AS LOW
DECK HAS BEEN OVERSPREADING THE AREA. LOOKS LIKE IT WILL TAKE A
BIT LONGER TO SCATTER OUT AND THUS TRENDED MOSTLY CLOUDY TO LAST
THROUGH MID AFTERNOON FOR MOST OF THE AREA. WITH THIS INCREASE IN
CLOUD COVER HAVE ALSO LOWER HIGH TEMPERATURES FOR THE DAY...ONLY
BY A DEGREE OR SO IN THE NORTH AND CENTRAL BUT BY A FEW DEGREES IN
THE SOUTHWEST SINCE DEBRIS CLOUDS WILL LIKELY KEEP THAT AREA
MOSTLY CLOUDY THROUGH MUCH OF THE DAY. RAP SHOWS SOME ISOLATED TO
SCATTERED CONVECTIVE DEVELOPMENT LATER THIS AFTERNOON BUT OTHER
MODELS STILL LOOK DRY. WITH SOME SUBSIDENCE AND DRY AIR ALOFT AND
THE RAP ALSO SHOWING SOME THINGS NOW THAT ARE NOT OCCURRING WILL
CONTINUE WITH DRY FORECAST THROUGH THE DAY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 243 AM EDT TUE AUG 6 2013
MAIN FOCUS DURING THIS PERIOD WILL BE POPS.
MODELS ARE IN PRETTY GOOD AGREEMENT OF THE OVERALL TREND OF A
WET...ACTIVE PATTERN.
GFS AND NAM BOTH SUGGEST THE FIRST SHORT WAVE ARRIVING IN THE AREA
LATE TONIGHT AMID THE NW FLOW ALOFT. FORECAST SOUNDINGS HINT AT A
SLOW TOP DOWN STYLE SATURATION BY 12Z. THUS WILL KEEP THE EVENING
DRY...BUT TREND TOWARD HIGHER CHANCES FOR RAIN DURING THE
OVERNIGHT HOURS. 310K GFS ISENTROPIC SURFACE ALSO SHOWS A GOOD
SURGE OF ISENTROPIC LIFT WITH SPECIFIC HUMIDITIES RISING TO NEAR
8 G/KG. WILL TREND LOWS AT OR ABOVE MAVMOS VALUES DUE TO EXPECTED
WARM AIR ADVECTION...CLOUDS...AND PRECIP.
ON WEDNESDAY MORNING...THE GFS AND NAM SUGGEST A COLD FRONT
TROUGH LINGERING ACROSS THE STATE AS THE UPPER SUPPORT FROM THE
OVERNIGHT PERIOD DEPARTS. FORECAST SOUNDINGS SUGGEST DRYING
OUT...HOWEVER PLENTY OF CAPE...IN EXCESS OF 2000 J/KG REMAINS
AVAILABLE. PWATS ARE ALSO NEAR 1.75 INCHES...VERY MOIST. CONVECTIVE
TEMPS ON WEDNESDAY AFTERNOON ARE VERY ATTAINABLE...IN THE LOWER
80S...AND THE GFS 310K ISENTROPIC SURFACE SHOWS STRONG LIFT WITH
AGAIN A VERY MOIST AIR MASS WITH SPECIFIC HUMIDITIES OVER 9 G/KG.
MEANWHILE AT THE SURFACE A WARM FRONT STALLS ACROSS SOUTHERN
INDIANA...FURTHER ACTING AS A FOCUS FOR LOWER LEVEL CONVERGENCE.
THUS ANY HEATING ON WEDNESDAY SHOULD LEAD TO DEVELOPMENT. WILL
TREND POPS AT OR ABOVE MAVMOS...PARTICULARLY DURING THE AFTERNOON.
GIVEN THE EXPECTED CLOUDS AND RAIN...WILL TREND HIGHS AT OR BELOW
MAVMOS.
GFS DEPICTS A SHORT WAVE RIDING ACROSS THE WARM FRONT ACROSS THE
SOUTHERN PARTS OF THE FORECAST AREA ON WEDNESDAY NIGHT...AGAIN A
VERY WARM AND MOIST AIR MASS WILL REMAIN IN PLACE. FORECAST
SOUNDINGS ACROSS THE AREA ALSO INDICATE DEEP SATURATION BY
THURSDAY...AND NOW WITH PWATS IN EXCESS OF 2 INCHES. FAVORABLE
CAPE IS ALSO AVAILABLE. ALOFT IT APPEARS AS IF THE TROPICAL PLUME
THAT IS CURRENTLY FLOWING ACROSS THE PLAINS INTO THE DEEP SOUTH WILL
SHIFT EAST BY WEDNESDAY AND THURSDAY...ALLOWING THIS DEEPER
MOISTURE TO SURGE INTO INDIANA AND THE OHIO VALLEY...PARTICULARLY
ACROSS THE SOUTHERN PARTS OF OUR STATE. THUS WILL CONTINUE TO
RAISE POPS THROUGH THURSDAY NIGHT...TRENDING HIGHS COOLER THAN
MAVMOS AND LOWS WARMER...GIVEN THE EXPECTED CLOUDS AND RAIN.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
ISSUED AT 223 AM EDT TUE AUG 6 2013
LONG TERM PERIOD WILL BE CHARACTERIZED BY ZONAL OR WEAKLY CYCLONIC
FLOW...WITH SURFACE HIGH PRESSURE LIKELY TO BE IN CONTROL ACROSS
THE AREA FROM THE WEEKEND ONWARD. FRONTAL BOUNDARY WILL BE
GRADUALLY EXITING THE REGION EARLY IN THE PERIOD...AND WILL
CONTINUE TO CARRY POPS FRIDAY AND FRIDAY NIGHT BEFORE GOING DRY
THE REST OF THE PERIOD. ALLBLEND WANTS TO INSERT POPS LATE IN THE
WEEKEND BUT AT THIS POINT MODELS LOOK OVERAGGRESSIVE FOR THE WEAK
FEATURES NOTED WELL UPSTREAM.
ZONAL TO WEAKLY CYCLONIC FLOW SUGGESTS TEMPS NEAR TO A BIT BELOW
NORMAL...AND ALLBLEND HANDLED THIS WELL WITH FEW TWEAKS REQUIRED.
&&
.AVIATION /UPDATED DISCUSSION FOR TAFS/...
ISSUED AT 958 AM EDT TUE AUG 6 2013
WILL EXTEND DURATION OF MVFR CLOUD DECKS AT ALL TAF SITES A LITTLE
LONGER INTO THE AFTERNOON BASED ON OBSERVED DECKS REMAINING FAIRLY
SOLID. ALSO SOUNDING FORECASTS KEEPING VERY SHALLOW BUT NEARLY
SATURATED LAYER THAT SLOWLY LIFTS TO NEAR 3000 FEET WITH HEATING.
KHUF ALSO FLIRTING WITH IFR CLOUD DECKS THAT ARE OVER ILLINOIS AND
TRYING TO SPREAD EAST. KLAF SHOULD REMAIN ABOVE 1000 FT DECKS
GIVEN ADJACENT ILLINOIS OBSERVATIONS. KIND AND KBMG SHOULD ALSO
REMAIN ABOVE 1000 FT AND THREAT TIME...IF ANY WOULD BE THROUGH
061500Z.
PREVIOUS DISCUSSION ISSUED AT 638 AM EDT TUE AUG 6 2013...
MVFR CEILINGS LIKELY TO PERSIST AT TIMES THROUGH MIDDAY TODAY. VFR
BEYOND THEN.
MVFR CEILINGS HAVE MOVED EASTWARD ACROSS THE AREA AND GUIDANCE HANGS
ONTO THEM THROUGH AT LEAST MIDDAY. THIS APPEARS REASONABLE AND SREF
PROBABILITIES AGREE. WILL INSERT TEMPO SCATTERED GROUPS LATER IN THE
MORNING AS THE CEILINGS WILL LIKELY BEGIN TO FLUCTUATE AS THEY LIFT.
MAINLY MID CLOUD BEYOND THIS MORNING. SOME SHOWERS/STORMS POSSIBLE
TONIGHT BUT FAIRLY UNCERTAIN AT THIS POINT...SO WILL LEAVE FOR LATER
PACKAGES.
WINDS WILL BE BELOW 10KT THROUGHOUT THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...CP
SHORT TERM...PUMA
LONG TERM....NIELD
AVIATION...TUCEK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
951 AM EDT TUE AUG 6 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 243 AM EDT TUE AUG 6 2013
WARMER AIR IS SET TO ARRIVE IN INDIANA TODAY AS HIGH PRESSURE OVER
THE EAST COAST PROVIDES A WARMER AND MORE HUMID SOUTHERLY FLOW
ALONG WITH DRY WEATHER. A MORE ACTIVE WEATHER PATTERN WILL TAKE
SHAPE THROUGH THE MIDDLE OF THE WEEK AS A COLD FRONT IS EXPECTED
TO PUSH TOWARD INDIANA LATE TONIGHT AND STALL ACROSS SOUTHERN
INDIANA THROUGH THURSDAY THE FRONT WILL BRING CHANCES FOR SHOWERS
AND STORMS FROM LATE TONIGHT THROUGH FRIDAY.
HIGH PRESSURE IS EXPECTED TO ARRIVE LATE FRIDAY AND BRING A RETURN
TO DRY WEATHER FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 944 AM EDT TUE AUG 6 2013
BUMPED UP CLOUD COVER THIS MORNING DUE TO SATELLITE TRENDS AS LOW
DECK HAS BEEN OVERSPREADING THE AREA. LOOKS LIKE IT WILL TAKE A
BIT LONGER TO SCATTER OUT AND THUS TRENDED MOSTLY CLOUDY TO LAST
THROUGH MID AFTERNOON FOR MOST OF THE AREA. WITH THIS INCREASE IN
CLOUD COVER HAVE ALSO LOWER HIGH TEMPERATURES FOR THE DAY...ONLY
BY A DEGREE OR SO IN THE NORTH AND CENTRAL BUT BY A FEW DEGREES IN
THE SOUTHWEST SINCE DEBRIS CLOUDS WILL LIKELY KEEP THAT AREA
MOSTLY CLOUDY THROUGH MUCH OF THE DAY. RAP SHOWS SOME ISOLATED TO
SCATTERED CONVECTIVE DEVELOPMENT LATER THIS AFTERNOON BUT OTHER
MODELS STILL LOOK DRY. WITH SOME SUBSIDENCE AND DRY AIR ALOFT AND
THE RAP ALSO SHOWING SOME THINGS NOW THAT ARE NOT OCCURRING WILL
CONTINUE WITH DRY FORECAST THROUGH THE DAY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 243 AM EDT TUE AUG 6 2013
MAIN FOCUS DURING THIS PERIOD WILL BE POPS.
MODELS ARE IN PRETTY GOOD AGREEMENT OF THE OVERALL TREND OF A
WET...ACTIVE PATTERN.
GFS AND NAM BOTH SUGGEST THE FIRST SHORT WAVE ARRIVING IN THE AREA
LATE TONIGHT AMID THE NW FLOW ALOFT. FORECAST SOUNDINGS HINT AT A
SLOW TOP DOWN STYLE SATURATION BY 12Z. THUS WILL KEEP THE EVENING
DRY...BUT TREND TOWARD HIGHER CHANCES FOR RAIN DURING THE
OVERNIGHT HOURS. 310K GFS ISENTROPIC SURFACE ALSO SHOWS A GOOD
SURGE OF ISENTROPIC LIFT WITH SPECIFIC HUMIDITIES RISING TO NEAR
8 G/KG. WILL TREND LOWS AT OR ABOVE MAVMOS VALUES DUE TO EXPECTED
WARM AIR ADVECTION...CLOUDS...AND PRECIP.
ON WEDNESDAY MORNING...THE GFS AND NAM SUGGEST A COLD FRONT
TROUGH LINGERING ACROSS THE STATE AS THE UPPER SUPPORT FROM THE
OVERNIGHT PERIOD DEPARTS. FORECAST SOUNDINGS SUGGEST DRYING
OUT...HOWEVER PLENTY OF CAPE...IN EXCESS OF 2000 J/KG REMAINS
AVAILABLE. PWATS ARE ALSO NEAR 1.75 INCHES...VERY MOIST. CONVECTIVE
TEMPS ON WEDNESDAY AFTERNOON ARE VERY ATTAINABLE...IN THE LOWER
80S...AND THE GFS 310K ISENTROPIC SURFACE SHOWS STRONG LIFT WITH
AGAIN A VERY MOIST AIR MASS WITH SPECIFIC HUMIDITIES OVER 9 G/KG.
MEANWHILE AT THE SURFACE A WARM FRONT STALLS ACROSS SOUTHERN
INDIANA...FURTHER ACTING AS A FOCUS FOR LOWER LEVEL CONVERGENCE.
THUS ANY HEATING ON WEDNESDAY SHOULD LEAD TO DEVELOPMENT. WILL
TREND POPS AT OR ABOVE MAVMOS...PARTICULARLY DURING THE AFTERNOON.
GIVEN THE EXPECTED CLOUDS AND RAIN...WILL TREND HIGHS AT OR BELOW
MAVMOS.
GFS DEPICTS A SHORT WAVE RIDING ACROSS THE WARM FRONT ACROSS THE
SOUTHERN PARTS OF THE FORECAST AREA ON WEDNESDAY NIGHT...AGAIN A
VERY WARM AND MOIST AIR MASS WILL REMAIN IN PLACE. FORECAST
SOUNDINGS ACROSS THE AREA ALSO INDICATE DEEP SATURATION BY
THURSDAY...AND NOW WITH PWATS IN EXCESS OF 2 INCHES. FAVORABLE
CAPE IS ALSO AVAILABLE. ALOFT IT APPEARS AS IF THE TROPICAL PLUME
THAT IS CURRENTLY FLOWING ACROSS THE PLAINS INTO THE DEEP SOUTH WILL
SHIFT EAST BY WEDNESDAY AND THURSDAY...ALLOWING THIS DEEPER
MOISTURE TO SURGE INTO INDIANA AND THE OHIO VALLEY...PARTICULARLY
ACROSS THE SOUTHERN PARTS OF OUR STATE. THUS WILL CONTINUE TO
RAISE POPS THROUGH THURSDAY NIGHT...TRENDING HIGHS COOLER THAN
MAVMOS AND LOWS WARMER...GIVEN THE EXPECTED CLOUDS AND RAIN.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
ISSUED AT 223 AM EDT TUE AUG 6 2013
LONG TERM PERIOD WILL BE CHARACTERIZED BY ZONAL OR WEAKLY CYCLONIC
FLOW...WITH SURFACE HIGH PRESSURE LIKELY TO BE IN CONTROL ACROSS
THE AREA FROM THE WEEKEND ONWARD. FRONTAL BOUNDARY WILL BE
GRADUALLY EXITING THE REGION EARLY IN THE PERIOD...AND WILL
CONTINUE TO CARRY POPS FRIDAY AND FRIDAY NIGHT BEFORE GOING DRY
THE REST OF THE PERIOD. ALLBLEND WANTS TO INSERT POPS LATE IN THE
WEEKEND BUT AT THIS POINT MODELS LOOK OVERAGGRESSIVE FOR THE WEAK
FEATURES NOTED WELL UPSTREAM.
ZONAL TO WEAKLY CYCLONIC FLOW SUGGESTS TEMPS NEAR TO A BIT BELOW
NORMAL...AND ALLBLEND HANDLED THIS WELL WITH FEW TWEAKS REQUIRED.
&&
.AVIATION /DISCUSSION FOR THE 06/12Z TAFS/...
ISSUED AT 638 AM EDT TUE AUG 6 2013
MVFR CEILINGS LIKELY TO PERSIST AT TIMES THROUGH MIDDAY TODAY. VFR
BEYOND THEN.
MVFR CEILINGS HAVE MOVED EASTWARD ACROSS THE AREA AND GUIDANCE HANGS
ONTO THEM THROUGH AT LEAST MIDDAY. THIS APPEARS REASONABLE AND SREF
PROBABILITIES AGREE. WILL INSERT TEMPO SCATTERED GROUPS LATER IN THE
MORNING AS THE CEILINGS WILL LIKELY BEGIN TO FLUCTUATE AS THEY LIFT.
MAINLY MID CLOUD BEYOND THIS MORNING. SOME SHOWERS/STORMS POSSIBLE
TONIGHT BUT FAIRLY UNCERTAIN AT THIS POINT...SO WILL LEAVE FOR LATER
PACKAGES.
WINDS WILL BE BELOW 10KT THROUGHOUT THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...CP
SHORT TERM...PUMA
LONG TERM....NIELD
AVIATION...NIELD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
921 AM EDT TUE AUG 6 2013
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE COULD TRIGGER A SHOWER OR
THUNDERSTORM THIS AFTERNOON. OTHERWISE, HIGH PRESSURE WILL BUILD
ACROSS THE AREA TODAY AND MOVE EAST OF THE REGION ON WEDNESDAY AS
ANOTHER FRONT APPROACHES FROM THE SOUTHWEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
9:00 AM UPDATE...BROUGHT TEMPS UP A DEGREE AND MADE SKIES MOSTLY
CLEAR ACROSS THE AREA WITH PLENTY OF SUNSHINE AROUND. EXPECT A FEW
CUMULUS TO DEVELOP THROUGH MIDDAY. AN ISOLATED THUNDERSHOWER IS
POSSIBLE IN SOME SPOTS.
PREVIOUS DISCUSSION...
DRIER AND MILDER TODAY.
A WEAK RIDGE OF HIGH PRES AT THE SFC IS SET TO MOVE OVER THE
REGION TODAY INTO TONIGHT. DRIER WEATHER W/MORE SUNSHINE WILL BE
SEEN TODAY W/TEMPERATURES RESPONDING INTO THE MID AND UPPER 70S.
THE CAVEAT TO THIS HOWEVER WILL BE A WEAK S/WV IN THE UPPER LEVELS
THAT WILL MOVE ACROSS THE STATE THIS AFTERNOON. THIS FEATURE IS
PICKED UP WELL BY THE 00Z NAM AND CANADIAN GEM PER 06Z ANALYSIS
OVER ONTARIO. IR SATL IMAGERY SHOWED SOME MID/HIGH CLOUDS ASSOCIATED
W/THIS FEATURE MOVING INTO WESTERN AND NORTHERN NYS. GFS/NAM
SOUNDINGS AS WELL AS THE GEM SHOW SOME MOISTURE AT THE 850MB LEVEL
W/THE MAJORITY OF THE RH ABOVE 700MBS. LATEST TRAJECTORIES BRING
SOME CLOUDINESS`S ACROSS PORTIONS OF WESTERN AND NORTHERN AREAS
TODAY. SOUNDINGS DO INDICATE SOME INSTABILITY AS LIS DROP TO -1 TO
-3 AND SBCAPES HIT CLOSE TO 500 JOULES. THERE IS SOME WEAK SHEAR
AT 0-6KM OF 15 KTS OR SO. 850-700MB LAPSE RATES FROM THE NAM ARE
CLOSE TO 7.0 C/KM AND SOME LLVL CONVERGENCE NOTED. ALL THIS COULD
BE ENOUGH TO TRIGGER SOME ISOLD SHOWERS OR PERHAPS A TSTM MAINLY
FOR THE WESTERN AND NWRN AREAS. THE NAM AND GFS HINT AT THIS TO
SET UP. EVEN THE 06Z HRRR SHOWS WIDELY SCATTERED TO ISOLD PRECIP.
THEREFORE, DECIDED TO ADD THE MENTION OF A SHOWER OR POSSIBLE
TSTM INTO LATE AFTERNOON(20%).
ACTIVITY WILL WIND DOWN IN THE EVENING AS THE S/WV MOVES TO THE E
AND LOSS OF HEATING. HIGH PRES IN THE GULF OF MAINE WILL RIDGE
OVER THE REGION TONIGHT. CLEARING SKIES AND COOLER TEMPERATURES
WILL ALLOW FOR SOME FOG TO DEVELOP. OVERNIGHT LOWS ARE EXPECTED
TO DROP BACK INTO THE UPPER 40S ACROSS THE N AND NW WHILE LOWER
50S SHOULD DO IT FOR CENTRAL AND DOWNEAST AREAS.SATURATED GROUND
AND DAYTIME HEATING WILL AID IN THE FOG DEVELOPMENT. ATTM, WENT
W/PATCHY FOG. DAYCREW CAN ASSESS THIS FURTHER TODAY.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL MOVE EAST OF THE REGION DURING WEDNESDAY. AFTER A
MAINLY SUNNY START TO THE DAY EXPECT INCREASING HIGH CLOUDS IN
ADVANCE OF THE NEXT TROF APPROACHING FROM THE WEST. THE MAIN
CHANGE TO THE WEDNESDAY FORECAST WAS TO DELAY THE ONSET OF ANY
SHOWERS GETTING INTO THE WESTERN AREAS UNTIL WEDNESDAY EVENING.
HIGH TEMPERATURES ON WEDNESDAY WILL BE CLOSE TO NORMAL FOR THIS
TIME OF YEAR WITH MID 70S TO NEAR 80 DEGREES ACROSS THE REGION.
CLOUDS WILL CONTINUE TO INCREASE WEDNESDAY NIGHT WITH SHOWERS
DEVELOPING FROM WEST TO EAST AFTER MIDNIGHT IN ADVANCE OF AN
APPROACHING WARM FRONT. LOWS WEDNESDAY NIGHT ARE EXPECTED TO RANGE
FROM THE MID TO UPPER 50S ACROSS THE REGION.
SHOWERS WILL CONTINUE TO BE LIKELY ON THURSDAY IN ADVANCE OF THE
APPROACHING COLD FRONT. HIGH TEMPERATURES ON THURSDAY WILL BE A BIT
BELOW NORMAL FOR THIS TIME OF YEAR DUE TO THE COMBINATION OF CLOUDS
AND SHOWERS. HIGHS WILL RANGE FROM THE UPPER 60S TO NEAR 70 DEGREES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE WEAK SURFACE COLD FRONT WILL SLOWLY CROSS THE REGION THURSDAY
NIGHT WITH SHOWERS TAPERING OFF FROM WEST TO EAST AFTER MIDNIGHT.
THE WEAKENING FRONT WILL STALL NEAR OR ALONG THE COAST LATER
THURSDAY NIGHT AND FRIDAY. LATEST MODEL GUIDANCE SUGGESTS FRIDAY
MAY BE A MAINLY DRY ALTHOUGH MOSTLY CLOUDY DAY.
A VIGOROUS 500MB LOW WILL MOVE EAST INTO QUEBEC LATER FRIDAY AND
SATURDAY. MODELS DIVERGE ON THE OVERALL SENSIBLE WEATHER FOR LATER
FRIDAY NIGHT AND INTO SATURDAY. THE 00Z OP RUN OF THE GFS DEVELOPS A
COMPACT SURFACE LOW ACROSS NYS FRIDAY NIGHT AND THEN TRACKS IT
ACROSS NEW ENGLAND AND ACROSS DOWNEAST MAINE FRIDAY NIGHT. 00Z EC IS
FURTHER SOUTH AND WEAKER WITH THE LOW KEEPING THE REGION MAINLY DRY.
FOR NOW HAVE KEPT CONTINUITY WITH GOING FORECAST AND WENT WITH LOW
CHANCE POPS FRIDAY NIGHT AND INTO SATURDAY.
COOLER AND DRIER AIR WILL WILL FOLLOW FOR LATE WEEKEND AND INTO
EARLY NEXT WEEK WITH TEMPERATURES AVERAGING BELOW SEASONAL FOR THIS
TIME OF YEAR.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: VFR THROUGH TONIGHT FOR ALL TERMINALS. THERE IS
POTENTIAL FOR SOME FOG TO DEVELOP LATE TONIGHT MAINLY ACROSS THE
NORTHERN TERMINALS DUE TO THE WET GROUND AND CLEARING. CONDITIONS
COULD BRIEFLY DROP TO MVFR OR PERHAPS IFR BY EARLY WEDNESDAY MORNING.
SHORT TERM: VFR WEDNESDAY. MVFR WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT IN SHOWERS. VFR FRIDAY AND SATURDAY.
&&
.MARINE...
NEAR TERM: NO HEADLINES THIS TERM. WINDS WILL TURN TO THE SW LATER
TODAY AND AVERAGE 10 KT OR SO. WAVE HEIGHTS WILL STAY AT 2-3 FT
MAINLY AWAY FROM THE INTRA-COASTAL ZONE.
SHORT TERM: WINDS/SEAS SHOULD REMAIN BELOW SCA LEVELS FOR THIS
TERM.
&&
.MARINE...
NEAR TERM:
SHORT TERM:
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...BLOOMER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
643 AM EDT TUE AUG 6 2013
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE COULD TRIGGER A SHOWER OR
THUNDERSTORM THIS AFTERNOON. OTHERWISE, HIGH PRESSURE WILL BUILD
ACROSS THE AREA TODAY AND MOVE EAST OF THE REGION ON WEDNESDAY AS
ANOTHER FRONT APPROACHES FROM THE SOUTHWEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
645 AM UPDATE: MODIFIED THE SKY AND TEMPERATURES TO BRING THEM TO
THE CURRENT CONDITIONS SHOWING MAINLY CLEAR AND COOL CONDITIONS.
SOME AREAS BACK ACROSS WEST AND NORTHWEST MAINE DROPPED BACK INTO
THE MID AND UPPER 30S W/LOWER 40S AT ALLAGASH AND DICKEY.
ELSEWHERE, READINGS WERE IN THE UPPER 40S AND LOWER 50S. EXPECTING
THOSE TEMPERATURES TO REBOUND AFTER 8 AM W/THE AID OF THE SUN.
PREVIOUS DISCUSSION...
DRIER AND MILDER TODAY.
A WEAK RIDGE OF HIGH PRES AT THE SFC IS SET TO MOVE OVER THE
REGION TODAY INTO TONIGHT. DRIER WEATHER W/MORE SUNSHINE WILL BE
SEEN TODAY W/TEMPERATURES RESPONDING INTO THE MID AND UPPER 70S.
THE CAVEAT TO THIS HOWEVER WILL BE A WEAK S/WV IN THE UPPER LEVELS
THAT WILL MOVE ACROSS THE STATE THIS AFTERNOON. THIS FEATURE IS
PICKED UP WELL BY THE 00Z NAM AND CANADIAN GEM PER 06Z ANALYSIS
OVER ONTARIO. IR SATL IMAGERY SHOWED SOME MID/HIGH CLOUDS ASSOCIATED
W/THIS FEATURE MOVING INTO WESTERN AND NORTHERN NYS. GFS/NAM
SOUNDINGS AS WELL AS THE GEM SHOW SOME MOISTURE AT THE 850MB LEVEL
W/THE MAJORITY OF THE RH ABOVE 700MBS. LATEST TRAJECTORIES BRING
SOME CLOUDINESS`S ACROSS PORTIONS OF WESTERN AND NORTHERN AREAS
TODAY. SOUNDINGS DO INDICATE SOME INSTABILITY AS LIS DROP TO -1 TO
-3 AND SBCAPES HIT CLOSE TO 500 JOULES. THERE IS SOME WEAK SHEAR
AT 0-6KM OF 15 KTS OR SO. 850-700MB LAPSE RATES FROM THE NAM ARE
CLOSE TO 7.0 C/KM AND SOME LLVL CONVERGENCE NOTED. ALL THIS COULD
BE ENOUGH TO TRIGGER SOME ISOLD SHOWERS OR PERHAPS A TSTM MAINLY
FOR THE WESTERN AND NWRN AREAS. THE NAM AND GFS HINT AT THIS TO
SET UP. EVEN THE 06Z HRRR SHOWS WIDELY SCATTERED TO ISOLD PRECIP.
THEREFORE, DECIDED TO ADD THE MENTION OF A SHOWER OR POSSIBLE
TSTM INTO LATE AFTERNOON(20%).
ACTIVITY WILL WIND DOWN IN THE EVENING AS THE S/WV MOVES TO THE E
AND LOSS OF HEATING. HIGH PRES IN THE GULF OF MAINE WILL RIDGE
OVER THE REGION TONIGHT. CLEARING SKIES AND COOLER TEMPERATURES
WILL ALLOW FOR SOME FOG TO DEVELOP. OVERNIGHT LOWS ARE EXPECTED
TO DROP BACK INTO THE UPPER 40S ACROSS THE N AND NW WHILE LOWER
50S SHOULD DO IT FOR CENTRAL AND DOWNEAST AREAS.SATURATED GROUND
AND DAYTIME HEATING WILL AID IN THE FOG DEVELOPMENT. ATTM, WENT
W/PATCHY FOG. DAYCREW CAN ASSESS THIS FURTHER TODAY.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL MOVE EAST OF THE REGION DURING WEDNESDAY. AFTER A
MAINLY SUNNY START TO THE DAY EXPECT INCREASING HIGH CLOUDS IN
ADVANCE OF THE NEXT TROF APPROACHING FROM THE WEST. THE MAIN
CHANGE TO THE WEDNESDAY FORECAST WAS TO DELAY THE ONSET OF ANY
SHOWERS GETTING INTO THE WESTERN AREAS UNTIL WEDNESDAY EVENING.
HIGH TEMPERATURES ON WEDNESDAY WILL BE CLOSE TO NORMAL FOR THIS
TIME OF YEAR WITH MID 70S TO NEAR 80 DEGREES ACROSS THE REGION.
CLOUDS WILL CONTINUE TO INCREASE WEDNESDAY NIGHT WITH SHOWERS
DEVELOPING FROM WEST TO EAST AFTER MIDNIGHT IN ADVANCE OF AN
APPROACHING WARM FRONT. LOWS WEDNESDAY NIGHT ARE EXPECTED TO RANGE
FROM THE MID TO UPPER 50S ACROSS THE REGION.
SHOWERS WILL CONTINUE TO BE LIKELY ON THURSDAY IN ADVANCE OF THE
APPROACHING COLD FRONT. HIGH TEMPERATURES ON THURSDAY WILL BE A BIT
BELOW NORMAL FOR THIS TIME OF YEAR DUE TO THE COMBINATION OF CLOUDS
AND SHOWERS. HIGHS WILL RANGE FROM THE UPPER 60S TO NEAR 70 DEGREES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE WEAK SURFACE COLD FRONT WILL SLOWLY CROSS THE REGION THURSDAY
NIGHT WITH SHOWERS TAPERING OFF FROM WEST TO EAST AFTER MIDNIGHT.
THE WEAKENING FRONT WILL STALL NEAR OR ALONG THE COAST LATER
THURSDAY NIGHT AND FRIDAY. LATEST MODEL GUIDANCE SUGGESTS FRIDAY
MAY BE A MAINLY DRY ALTHOUGH MOSTLY CLOUDY DAY.
A VIGOROUS 500MB LOW WILL MOVE EAST INTO QUEBEC LATER FRIDAY AND
SATURDAY. MODELS DIVERGE ON THE OVERALL SENSIBLE WEATHER FOR LATER
FRIDAY NIGHT AND INTO SATURDAY. THE 00Z OP RUN OF THE GFS DEVELOPS A
COMPACT SURFACE LOW ACROSS NYS FRIDAY NIGHT AND THEN TRACKS IT
ACROSS NEW ENGLAND AND ACROSS DOWNEAST MAINE FRIDAY NIGHT. 00Z EC IS
FURTHER SOUTH AND WEAKER WITH THE LOW KEEPING THE REGION MAINLY DRY.
FOR NOW HAVE KEPT CONTINUITY WITH GOING FORECAST AND WENT WITH LOW
CHANCE POPS FRIDAY NIGHT AND INTO SATURDAY.
COOLER AND DRIER AIR WILL WILL FOLLOW FOR LATE WEEKEND AND INTO
EARLY NEXT WEEK WITH TEMPERATURES AVERAGING BELOW SEASONAL FOR THIS
TIME OF YEAR.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: VFR THROUGH TONIGHT FOR ALL TERMINALS. THERE IS
POTENTIAL FOR SOME FOG TO DEVELOP LATE TONIGHT MAINLY ACROSS THE
NORTHERN TERMINALS DUE TO THE WET GROUND AND CLEARING. CONDITIONS
COULD BRIEFLY DROP TO MVFR OR PERHAPS IFR BY EARLY WEDNESDAY MORNING.
SHORT TERM: VFR WEDNESDAY. MVFR WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT IN SHOWERS. VFR FRIDAY AND SATURDAY.
&&
.MARINE...
NEAR TERM: NO HEADLINES THIS TERM. WINDS WILL TURN TO THE SW LATER
TODAY AND AVERAGE 10 KT OR SO. WAVE HEIGHTS WILL STAY AT 2-3 FT
MAINLY AWAY FROM THE INTRA-COASTAL ZONE.
SHORT TERM: WINDS/SEAS SHOULD REMAIN BELOW SCA LEVELS FOR THIS
TERM.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT/DUDA
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
822 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN PARKED OFFSHORE THROUGH THE END OF THE
WEEK. SOUTHERLY RETURN FLOW AROUND THE HIGH WILL DRAW TROPICAL
MOISTURE UP THE EASTERN SEABOARD. A COLD FRONT IS EXPECTED TO MOVE
THROUGH THE MID-ATLANTIC STATES FRIDAY NIGHT AND SATURDAY. HIGH
PRESSURE BRIEFLY BUILDS IN LATE THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...CANCELLED COASTAL FLOOD ADZY FOR ANNE ARUNDEL CO.
WIDESPREAD SHOWERS W/ EMBEDDED POCKETS OF HEAVIER RAIN WILL
CONTINUE TO SPREAD ACROSS THE I-95 CORRIDOR. HRRR SEEMS TO HAVE
THE BEST HANDLE ON THIS EVOLVING SITUATION BASED ON EARLY MORNING
RADAR TRENDS.
THIS ACTIVITY WILL COLLECT ALONG THE I-95 CORRIDOR AND THE
CHESAPEAKE BAY REGION LATER THIS MRNG...MORE SCATTERED SHOWERS AND
A FEW ISOLATED TSTMS POSSIBLE THIS AFTN/EVE.
AFTER THAT WAVE SLIDES EAST OF US BY MID TO LATE MORNING. MOST
MESOMODELS SHOW SCATTERED CONVECTION DEVELOPING IN THE WARM
ADVECTION ENVIRONMENT FOR THE AFTERNOON AND TUE NIGHT FAIRLY
EVENLY ACROSS THE FORECAST AREA. GIVEN THE WEAK AND DIFFUSE
FORCING WITH THIS...AM NOT CURRENTLY ABLE TO PUT MUCH DETAIL INTO
WHERE THE BEST CHANCES ARE IN TIME AND AREA.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
A CLOSED LOW WILL MEANDER OVER MANITOBA WHILE AN UPPER RIDGE IS
PARKED OVER THE GULF COAST STATES THRU THE SHORT-TERM PERIOD. UPPER
FLOW PATTERN BETWEEN THESE TWO SYSTEMS WILL BE FAIRLY ZONAL DURING
THIS TIME WITH THE MID-ATLANTIC REGION SITUATED ON SRN PERIPHERY OF
STRONGER WESTERLIES. A SERIES OF SHORTWAVE DISTURBANCES WILL ROTATE
AROUND THE BASE OF THE UPPER TROUGH WITHIN THIS BELT OF ENHANCED
WESTERLIES DURING THE SECOND HALF OF THE WEEK.
IN THE LLVLS AND AT THE SFC...SLY RETURN FLOW AROUND HIPRES OVER THE
WRN ATLANTIC WILL TRANSPORT MOISTURE FROM THE CARIBBEAN UP THE ERN
SEABOARD. PWATS INCREASE FROM AROUND 1.5 INCHES WED MRNG TO 2 INCHES
BY THU. IT WILL NOT REQUIRE A WHOLE LOT OF FORCING FROM EACH
SHORTWAVE TROUGH TO PRODUCE SHOWERS AND TSTMS IN THIS TROPICAL
AIRMASS. LOWERED POPS A BIT FROM PREV FCST WITH THE BEST FORCING
EXPECTED TO REMAIN NORTH AND WEST OF THE AREA DURING THE SHORT TERM.
POPS CLOSELY FOLLOW DIURNAL CYCLE AND ARE HIGHEST EACH DAY DURING
THE AFTN/EVE HRS. WITH EXTENSIVE CLOUD COVER OVER THE AREA...THERE
IS SOME FCST UNCERTAINTY REGARDING TSTM COVERAGE...WHICH WILL DEPEND
ON AMT OF DAYTIME HEATING. ANY STORMS WILL HAVE THE POTENTIAL TO
PRODUCE LOCALLY HVY RAINFALL...ESPECIALLY ON THU.
HUMID AIRMASS AND CLOUDS COVER WILL YIELD BELOW NORMAL HIGHS AND
ABOVE NORMAL LOWS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE VERTICALLY-STACKED LOW WILL PROGRESS SLOWLY EWD ACROSS CENTRAL
ONTARIO FRI. A LEADING SHORTWAVE DISTURBANCE ROTATING AROUND THE
BASE OF THE LARGE-SCALE TROUGH IS FCST TO MOVE FROM THE GREAT
LAKES/OH VLY TO THE NRN MID-ATLANTIC AND NORTHEAST STATES DURING
THIS TIME. THIS DISTURBANCE WILL PROVIDE SOME WEAK LIFT FOR
SHOWERS AND STORMS ESPECIALLY DURING THE PEAK HEATING HRS. YDA`S
MODELS SHOWED A COLD FRONT BECOMING STALLED OVER THE AREA ON FRI.
NOW...THE LATEST 00Z ECMWF...GFS AND ITS ENSEMBLE MEMBERS INDICATE
THE BOUNDARY REMAINING NORTH OF THE AREA. GIVEN THE SLOWING
TREND...POPS WERE LOWERED AND THE POTENTIAL FOR MORE WIDESPREAD
HEAVY RAIN NOT AS HIGH AS IT APPEARED TO BE YDA.
NONETHELESS...PWATS WILL BE ABOVE 2 INCHES...SO ANY STORMS THAT
DEVELOPS WILL BE EFFICIENT RAINFALL PRODUCERS. CONVECTION FRI AFTN
MAY FOCUS ALONG A LEE TROUGH THAT FORMS AHEAD OF THE MAIN COLD
FRONT.
THE AFOREMENTIONED SHORTWAVE TROUGH WILL MOVE ACROSS NRN NEW ENGLAND
FRI NGT. NW FLOW BEHIND THE TROUGH WILL HELP PUSH THE COLD FRONT
TOWARD THE MASON-DIXON LINE LATE FRI NGT. DIURNALLY-DRIVEN
CONVECTION EXPECTED TO WANE AFTER SUNSET.
WITH A LATER TIMING IN THE FROPA AND COOLER...DRIER AND MORE STABLE
AIR LAGGING BEHIND THE FRONT...FCST HAS TRENDED WETTER FOR THE SRN
HALF OF THE CWA ON SAT. EXPECT SHOWERS AND STORMS TO DEVELOP DURING
THE PEAK HEATING HRS. THE HIGHEST POPS RESIDE OVER THE CENTRAL VA
AND LWR SRN MD...WHICH WILL BE LOCATED CLOSEST TO LLVL CONVERGENCE
NEAR THE FRONT.
THE FRONTAL BOUNDARY IS EXPECTED TO STALL SOUTH OF THE AREA ON SUN
BEFORE LIFTING BACK NORTHWARD AS A WARM FRONT ON MON. DRY WEATHER TO
CLOSED OUT THE WEEKEND WILL BE SHORT LIVED AS SHOWERS AND STORMS
RETURN ERY NEXT WEEK.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
EXPECTING MVFR CONDITIONS TO MOVE IN THIS MORNING AND LAST INTO
WED. SHOWER THREAT WILL BE THERE..ESP FOR CHO THIS MORNING. ALSO
AN ISOLATED CHANCE FOR A TSTM.
MOIST SLY RETURN FLOW WILL BE ACCOMPANIED BY DAILY CHANCES FOR SHRA
AND TSRA DURING THE SECOND HALF OF THE WEEK. CONVECTION WILL BE
PREDOMINANTLY DIURNALLY-DRIVEN AND SCT IN NATURE. THE POTENTIAL IS
THERE FOR PERIODS OF LOW CLOUDS AND FOG EACH NGT/ERY MRNG GIVEN THE
MOIST BOUNDARY LAYER IN PLACE. A COLD FRONT MOVES THRU THE TERMINALS
FRI NGT AND SAT.
&&
.MARINE...
SCA HAS BEEN ISSUED FOR LATER TODAY INTO WED FOR THE BAY CHANNEL S
OF ANNAP AND THE LOWER TIDAL POTOMAC.
SCA HAS BEEN EXTENDED INTO WED FOR MOST OF THE MD CHSPK BAY AND THE
MOUTH OF THE TIDAL POTOMAC. SLY FETCH WILL PROMOTE CHANNELING IN
THESE ZONES.
HIPRES MOVES FARTHER OFFSHORE THU AND FRI. CHANNELING WILL STILL
ENHANCE WIND SPEEDS TO AROUND 15 KT IN THE BAY.
&&
.TIDES/COASTAL FLOODING...
SLY FLOW WILL CONTINUE THROUGH THE END OF THE WEEK AS HIGH PRESSURE
REMAINS OFF THE EAST COAST. THE HIGHER OF THE HIGH TIDE WILL BE THE
ONE TO WATCH FOR POTENTIAL MINOR TIDAL FLOODING WITH THE NEW MOON
EXPECTED MID WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM TO 6 PM EDT WEDNESDAY FOR
ANZ531-539.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 PM EDT
WEDNESDAY FOR ANZ532>534-537-540>543.
&&
$$
UPDATE...GMS
PREV DISCUSSION...CAS/JRK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1152 AM EDT TUE AUG 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 548 AM EDT TUE AUG 6 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN UNUSUALLY DEEP VORTEX
FOR EARLY AUG CENTERED JUST S OF HUDSON BAY ALONG THE
MANITOBA/ONTARIO BORDER. ACROSS THE UPPER LAKES...FLOW HAS BECOME
MORE WESTERLY OVER THE LAST DAY OR TWO IN RESPONSE TO THE
DEEPENING/EXPANDING VORTEX THAT HAS BEEN DRIFTING S. SEVERAL
SHORTWAVES ARE EVIDENT UPSTREAM WITH 2 MORE NOTABLE WAVES OVER ERN
MT/SRN SASKATCHEWAN AND OVER ERN ALBERTA. THESE 2 WAVES WILL POWER A
COLD FRONT ACROSS UPPER MI TONIGHT AND WEDNESDAY MORNING. CLOSER TO
HOME...ISOLD/SCT SHRA (EVEN ISOLD TSRA AT TIMES) HAVE BEEN OCCURRING
OVER THE LAST SEVERAL HRS OVER WRN UPPER MI/ADJACENT LAKE SUPERIOR.
THESE SHRA ARE JUST AHEAD OF A 700MB TROF AND SURGE OF MIDLEVEL
DRYING PER BY LATEST RUC.
FOCUS EARLY THIS MORNING WILL BE ON THE ISOLD/SCT SHRA OVER THE W.
AS AFOREMENTIONED 700MB TROF CONTINUES TO PUSH E...WILL PROBABLY
CONTINUE TO SEE SOME SHRA SPREAD E INTO CNTRL UPPER MI OVER THE NEXT
SEVERAL HRS. LATEST SPC MESOANALYSIS SHOWS MUCAPE AROUND 250J/KG...
SO THERE MIGHT BE AN OCNL LIGHTNING STRIKE THOUGH THERE HAS NOT BEEN
ANY CG STRIKES FOR THE LAST COUPLE OF HRS. AS THE TROF CONTINUES
EASTWARD...IT WILL COINCIDE WITH THE HEATING CYCLE AND SHOULD AID
SHRA/TSRA DEVELOPMENT OVER THE ERN PART OF THE FCST AREA LATE THIS
MORNING/EARLY THIS AFTN...ESPECIALLY INLAND FROM LAKE MICHIGAN. SOME
HIGH RES GUIDANCE (NAM NEST AND RUC13) INDICATE LAKE BREEZE WILL
DEVELOP OFF LAKE SUPERIOR OVER THE E...BUT WILL MAKE LIMITED INLAND
PROGRESS. IF SO...CONVERGENCE ZONE WILL BE A GOOD FOCAL POINT FOR
CONVECTION. TO THE W ACROSS THE W HALF OF UPPER MI...THE SAME HIGH
RES GUIDANCE POINTS TO A MORE ACTIVE INLAND PUSH OF LAKE SUPERIOR
LAKE BREEZE. IN THE FLOW UPSTREAM...THERE ARE PROBABLY SOME SUBTLE
SHORTWAVES PRESENT GIVEN THE SCT CLUSTERS OF SHRA/TSRA THAT WERE
PRESENT EARLIER IN THE NIGHT ACROSS THE NRN PLAINS. WITH EXPECTATION
OF LOW CLOUDS CLEARING OUT/TRANSITIONING TO CU FIELD...DAYTIME
HEATING WILL LIKELY BE SUFFICIENT TO RAISE MLCAPE TO 500J/KG OR SO
PER NAM/GFS. LAKE BREEZE AND ANY SUBTLE SHORTWAVES SHOULD THEN
SUPPORT SCT SHRA/TSRA DEVELOPMENT. WITH DEEP LAYER SHEAR AROUND
35KT...SOME ORGANIZED/STRONGER STORMS ARE POSSIBLE. IF CAPE ENDS UP
HIGHER THAN CURRENTLY EXPECTED...THERE MIGHT BE AN ISOLD SVR STORM
OR TWO.
TONIGHT...THE STRONGER SHORTWAVES WELL UPSTREAM WILL PUSH A COLD
FRONT INTO UPPER MI. AS HAS BEEN THE CASE FOR THE LAST SEVERAL
DAYS...MODELS CONTINUE TO POINT TOWARD A GOOD POTENTIAL OF SHRA/TSRA
SPREADING ACROSS THE FCST AREA. WITH RATHER VIGOROUS DEEP LAYER
FORCING...STRONG MOISTURE TRANSPORT AND SHARP LOW LEVEL TROF
SHIFTING E...WILL RETAIN LIKELY POPS SPREADING E ACROSS THE AREA
TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 548 AM EDT TUE AUG 6 2013
AMPLIFIED UPPER AIR PATTERN PERSISTS THROUGH THE UPCOMING WEEKEND
AND LIKELY INTO NEXT WEEK AS WELL. MEAN TROUGHING DOMINATES MUCH OF
EASTERN CANADA ACROSS THE GREAT LAKES. PRIMARY RESULT OF THIS
PATTERN WILL BE CONTINUATION OF COOLER THAN NORMAL TEMPERATURES
THROUGH AT LEAST MID AUGUST ACROSS UPPER GREAT LAKES REGION. TO
START OUT ON WEDNESDAY...MAIN FEATURES ALOFT ARE CLOSED OFF UPPER
LOW CENTERED ALONG MANITOBA AND NORTHERN ONTARIO BORDER...SHARP WEST
TO EAST RIDGE OVER FAR NORTHERN CANADA AND A DOUBLE BARRELED TROUGH
EXTENDING FROM THE NORTH POLE SOUTHWEST ACROSS ALASKA AND TO THE
NORTHERN PORTIONS OF PACIFIC OCEAN. NOT A WHOLE LOT OF CHANGE WRT
LOCATIONS OF SAID FEATURES THROUGH THE LONG TERM. ONLY THING THAT
DOES CHANGE IS UPPER LOW OVER ONTARIO SLIDES ACROSS QUEBEC THIS
WEEKEND AS STRONGER JET ENERGY BECOMES PLACED OUT AHEAD OF THE
TROUGH...KEEPING IT MORE PROGRESSIVE. MAIN CHANCE OF RAIN IN THIS
PATTERN WILL BE RIGHT OFF THE BAT ON WEDNESDAY MORNING OVER EAST
HALF OF CWA AS COLD FRONT MOVES THROUGH REGION. ADDITIONAL CHANCES
OF RAIN POSSIBLE THURSDAY NIGHT INTO FRIDAY AS SECONDARY LOW PRESSURE
SYSTEM AND COLD FRONT CROSS THE AREA. GENERALLY LOOKS QUIET THROUGH
THE WEEKEND...BUT COOL. NEXT CHANCE OF RAIN PROBABLY ARRIVES LATER
SUNDAY NIGHT INTO MONDAY AS SHORTWAVES DROP ACROSS AREA IN NW FLOW
ALOFT.
COLD FRONT SHOULD BE OVER CNTRL UPR MICHIGAN TO START THE DAY ON
WEDNESDAY...QUICKLY HEADING EAST TO AROUND ERY BTWN 15Z-18Z. NAM
STILL ON THE FAST SIDE...WHILE ECMWF IS SLOWEST. COMPROMISE SOLN
WITH FRONT IS THE GFS/GEM-REGIONAL AS WELL AS NCEP WRF-ARW/NMM.
MAJORITY OF WIDESPREAD SHRA/TSRA WILL BE ALONG AND AHEAD OF FRONT
IN WARM AIR ADVECTION REGIME. GOING FCST LOOKS PRETTY GOOD.
CHANGES TO POPS ON WEDNESDAY WITH FROPA PRETTY MINIMAL. KEPT
LIKELY POPS OVR FAR EAST THROUGH 15Z...THEN TRIMMED BACK QUICKLY
WITH ARRIVAL OF STRONG MID-LEVEL DRYING AND AS PRIMARY H85 MOISTURE
ADVECTION IS EAST OF CWA. SOUNDINGS INDICATE LINGERING LOW-LEVEL
MOISTURE BEHIND COLD FRONT THAT COULD LEAD TO BRIEF PERIOD OF LGT
RAIN/DRIZZLE IN THE MORNING FOR AREAS NEAR LK SUPERIOR.
EVENTUALLY...BLYR BECOMING MIXED ALONG WITH NEGATIVE SFC-H85 THETA-E
ADVECTION WILL SHUT DOWN ANY LINGERING PRECIP BY MIDDAY. HAVE NO
POPS AFTER 18Z WHICH WAS A BIT OF A CHANGE COMPARED TO PREVIOUS
FCST. BKN CU/SC DECK MAY REMAIN LONGER THAN THIS...BUT EVEN THAT
SHOULD TEND TO MIX OUT TO PARTLY CLOUDY SKIES BY MID-LATE AFTN.
TEMPS TRICKY WITH FROPA AS 925-850MB TEMPS JUST AHEAD OF FRONT ARE
PRETTY WARM. FIGURING OUT HOW THE WARM AIR BALANCES BTWN COOLING
FROM CLOUDS/PRECIP IS MAIN HURDLE. WILL GO FOR MAX TEMPS TOPPING OUT
IN THE LOW 70S...WARMEST SOUTH CENTRAL. TEMPS ALONG LK SUPERIOR
COULD RISE EARLY ON...BUT THEN FALL BACK IN THE AFTN WITH INCREASING
ONSHORE FLOW. SHOULD BE ESPECIALLY NOTABLE NEAR MQT-P53. FOG THAT IS
DEVELOPING ACROSS LK SUPERIOR CURRENTLY MAY GET SHOVED ONSHORE TOO
FOR A WHILE.
SFC HIGH RIDGES IN FROM CANADIAN PRAIRIE PROVINCES WEDNESDAY NIGHT
INTO THURSDAY AHEAD OF NEXT COLD FRONT. H85 WINDS STAY ONSHORE ALL
NIGHT...BUT LOWEST LEVEL WINDS THROUGH 900MB BECOME LESS
SO...ALLOWING POTENTIAL FOR TYPICAL COOL SPOTS INLAND FROM THE GREAT
LAKES TO SEE TEMPS FALL INTO THE LOWER 40S. LIGHT GRADIENT WINDS ON
THURSDAY ALLOWS IN LIGHT LAKE BREEZES ALONG BOTH SUPERIOR AND
MICHIGAN. AWAY FM LOCAL COOLING THOUGH...TEMPS SHOULD BOUNCE BACK
INTO AT LEAST THE LOWER 70S MOST AREAS GIVEN H85 TEMPS WARMER THAN
+10C. THICKENING MID CLOUDS /H6-H5/ FOR WEST HALF BY AFTN AS WARM
AIR ADVECTION DEVELOPS AHEAD OF THE COLD FRONT. GFS HAS SHOWED
STEADY TREND IN BACKING OFF QPF INTO WESTERN TIER. USED A BLEND OF
MORE CONSISTENT ECMWF AND THE DRIER TRENDING GFS. RESULT WAS SOME
LOWER CHANCE POPS FOR WESTERN LK SUPERIOR/ISLE ROYALE ON NOSE OF
H85-H7 MOISTURE ADVECTION. AS SFC LOW SPINS OVER NORTHERN ONTARIO
THE COLD FRONT WILL SLOWLY SINK NORTH TO SOUTH ACROSS LK SUPERIOR
ON THURSDAY NIGHT. BEST CHANCE FOR SHRA/ISOLD TSRA WILL BE OVR LK
SUPERIOR DUE TO H85 TEMP ADVECTION/WEAK LOW-LEVEL JET AND SOME
LOW-LEVEL FRONTAL CONVERGENCE. TEMPS WILL BE ON THE MILD SIDE
AGAIN WITH SOUTH WINDS/WARM AIR ADVECTION AHEAD OF FRONT. COLD
FRONT WORKS ACROSS UPR MICHIGAN ON FRIDAY...SO WILL KEEP WITH
SOME LOWER CHANCE POPS. COOLING BEGINS ON FRIDAY...ESPECIALLY NEAR
LK SUPERIOR. INLAND...TEMPS MAY END UP ONLY A COUPLE DEGREES COOLER
THAN THURSDAY.
STRONG DRYING BEHIND FRONT FOR FRIDAY NIGHT AND SATURDAY. JUST SOME
SCT CU SHOULD DEVELOP DURING PEAK HEATING ON SATURDAY. H85 TEMPS
ONLY UP TO +6C WITH STRONGER ONSHORE FLOW WILL LEAD TO A COOL DAY
BY AUGUST STANDARDS WITH READINGS IN THE UPPER 50S/NEAR 60 ALONG LK
SUPERIOR AND MAYBE REACHING 70 DEGREES IN THE FAR SOUTH CENTRAL NEAR
MNM. 60S ELSEWHERE...WHICH IS AT LEAST 10 DEGREES BLO NORMAL.
NOT MUCH IN WAY OF CHANGES TO REST OF CONSENSUS GRIDS FOR EXTENDED.
SLIGHT CHANCE POPS FOR SUNDAY...THOUGH THESE ARE BIASED BY A LATEST
GFS WHICH TRENDED MUCH WETTER FOR PARTS OF CWA COMPARED TO PREVIOUS
RUNS. ECMWF INDICATES SMALL CHANCES OF INSTABILITY SHRA/TSRA AS
ANOTHER STRONGER WAVE OR TWO /CURRENTLY WITHIN THE LARGER TROUGH FM
ALASKA TO THE NORTH POLE/ DROPS ACROSS UPPER LAKES. POCKET OF STEEPER
MID-LEVEL LAPSE RATES WOULD JUSTIFY AT LEAST A MENTION OF TSRA DURING
PEAK HEATING OF SUNDAY AFTN LINGERING INTO SUN EVENING. SIMILAR SETUP
FOR MONDAY THOUGH BY THAT TIME BETTER FORCING IS SLIDING EAST AND
SOUTH OF LK SUPERIOR REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1151 AM EDT TUE AUG 6 2013
SLIGHTLY DRIER AIR ACROSS NE MN THIS MORNING HAS HAD A DIFFICULT
TIME MOVING INTO UPPER MI. EVEN WITH ABUNDANT LOW LEVEL
MOISTURE...AND AN ADDITIONAL PUSH OUT OF WI ON S-SW WINDS...CEILINGS
HAVE BEEN ABLE TO SLOWLY RISE INTO MVFR CATEGORY THANKS IN PART TO
BETTER MIXING /DAYTIME HEATING/. VFR CONDITIONS WILL BE POSSIBLE
THIS AFTERNOON AHEAD OF A COLD FRONT NEARING FROM MN...WITH
DETERIORATING CONDITIONS AGAIN BY THE MID-LATE EVENING HOURS. THERE
IS A POTENTIAL FOR A BROKEN LINE OF POP UP SHOWERS AND THUNDERSTORMS
OVER MAINLY CENTRAL AND E UPPER MI THIS AFTERNOON. WILL KEEP MENTION
OF VCSH AT SAW...WITH THE POTENTIAL OF ADDING TS/CB IF ANYTHING
LOOKS MORE CERTAIN. COLD FRONT WILL MOVE INTO UPPER MI
TONIGHT...BRINGING A PERIOD OF SHRA/TS AND A RETURN TO MVFR AND
POSSIBLY IFR CONDITIONS. ONCE FRONT PASSES...UPSLOPE FLOW AT
KIWD/KCMX AND TO A LESSER EXTENT SAW WILL RESULT IN LIFR CONDITIONS
WHICH WILL LINGER THROUGH THE MID MORNING HOURS BEFORE QUICKLY
CLEARING DURING THE MID-LATE MORNING HOURS W TO E.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 548 AM EDT TUE AUG 6 2013
LIGHT WINDS THROUGH MUCH OF TONIGHT THEN WINDS WILL KICK UP AS COLD
FRONT CROSSES LK SUPERIOR LATE TONIGHT THROUGH WEDNESDAY MORNING. NW
WINDS BEHIND COLD FRONT MAY REACH 20-25 KTS IN GUSTS. SHOWERS AND
STORMS LIKELY WITH THE FRONTAL PASSAGE. SHIP REPORTS INDICATE FOG
HAS FORMED OVERNIGHT WITH ARRIVAL OF MOIST AIRMASS. EXPECT THE FOG
TO CONTINUE UNTIL WEDNESDAY AFTERNOON WHEN DRIER AIR SCOURS OUT THE
FOG. WINDS DIMINISH TO LESS THAN 20 KTS WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT WITH HIGH PRESSURE OVERHEAD. STRONGER W-NW WINDS
POSSIBLE FRIDAY AND FRIDAY NIGHT AS ANOTHER COLD FRONT CROSSES
LAKE SUPERIOR FROM NORTH TO SOUTH. GUSTS COULD REACH OVER 25 KTS.
WINDS DIMINISH TO LESS THAN 20 KTS FOR REST OF WEEKEND WITH WEAKER
PRESSURE GRADIENT BY THAT TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...KF
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
740 AM EDT TUE AUG 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 548 AM EDT TUE AUG 6 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN UNUSUALLY DEEP VORTEX
FOR EARLY AUG CENTERED JUST S OF HUDSON BAY ALONG THE
MANITOBA/ONTARIO BORDER. ACROSS THE UPPER LAKES...FLOW HAS BECOME
MORE WESTERLY OVER THE LAST DAY OR TWO IN RESPONSE TO THE
DEEPENING/EXPANDING VORTEX THAT HAS BEEN DRIFTING S. SEVERAL
SHORTWAVES ARE EVIDENT UPSTREAM WITH 2 MORE NOTABLE WAVES OVER ERN
MT/SRN SASKATCHEWAN AND OVER ERN ALBERTA. THESE 2 WAVES WILL POWER A
COLD FRONT ACROSS UPPER MI TONIGHT AND WEDNESDAY MORNING. CLOSER TO
HOME...ISOLD/SCT SHRA (EVEN ISOLD TSRA AT TIMES) HAVE BEEN OCCURRING
OVER THE LAST SEVERAL HRS OVER WRN UPPER MI/ADJACENT LAKE SUPERIOR.
THESE SHRA ARE JUST AHEAD OF A 700MB TROF AND SURGE OF MIDLEVEL
DRYING PER BY LATEST RUC.
FOCUS EARLY THIS MORNING WILL BE ON THE ISOLD/SCT SHRA OVER THE W.
AS AFOREMENTIONED 700MB TROF CONTINUES TO PUSH E...WILL PROBABLY
CONTINUE TO SEE SOME SHRA SPREAD E INTO CNTRL UPPER MI OVER THE NEXT
SEVERAL HRS. LATEST SPC MESOANALYSIS SHOWS MUCAPE AROUND 250J/KG...
SO THERE MIGHT BE AN OCNL LIGHTNING STRIKE THOUGH THERE HAS NOT BEEN
ANY CG STRIKES FOR THE LAST COUPLE OF HRS. AS THE TROF CONTINUES
EASTWARD...IT WILL COINCIDE WITH THE HEATING CYCLE AND SHOULD AID
SHRA/TSRA DEVELOPMENT OVER THE ERN PART OF THE FCST AREA LATE THIS
MORNING/EARLY THIS AFTN...ESPECIALLY INLAND FROM LAKE MICHIGAN. SOME
HIGH RES GUIDANCE (NAM NEST AND RUC13) INDICATE LAKE BREEZE WILL
DEVELOP OFF LAKE SUPERIOR OVER THE E...BUT WILL MAKE LIMITED INLAND
PROGRESS. IF SO...CONVERGENCE ZONE WILL BE A GOOD FOCAL POINT FOR
CONVECTION. TO THE W ACROSS THE W HALF OF UPPER MI...THE SAME HIGH
RES GUIDANCE POINTS TO A MORE ACTIVE INLAND PUSH OF LAKE SUPERIOR
LAKE BREEZE. IN THE FLOW UPSTREAM...THERE ARE PROBABLY SOME SUBTLE
SHORTWAVES PRESENT GIVEN THE SCT CLUSTERS OF SHRA/TSRA THAT WERE
PRESENT EARLIER IN THE NIGHT ACROSS THE NRN PLAINS. WITH EXPECTATION
OF LOW CLOUDS CLEARING OUT/TRANSITIONING TO CU FIELD...DAYTIME
HEATING WILL LIKELY BE SUFFICIENT TO RAISE MLCAPE TO 500J/KG OR SO
PER NAM/GFS. LAKE BREEZE AND ANY SUBTLE SHORTWAVES SHOULD THEN
SUPPORT SCT SHRA/TSRA DEVELOPMENT. WITH DEEP LAYER SHEAR AROUND
35KT...SOME ORGANIZED/STRONGER STORMS ARE POSSIBLE. IF CAPE ENDS UP
HIGHER THAN CURRENTLY EXPECTED...THERE MIGHT BE AN ISOLD SVR STORM
OR TWO.
TONIGHT...THE STRONGER SHORTWAVES WELL UPSTREAM WILL PUSH A COLD
FRONT INTO UPPER MI. AS HAS BEEN THE CASE FOR THE LAST SEVERAL
DAYS...MODELS CONTINUE TO POINT TOWARD A GOOD POTENTIAL OF SHRA/TSRA
SPREADING ACROSS THE FCST AREA. WITH RATHER VIGOROUS DEEP LAYER
FORCING...STRONG MOISTURE TRANSPORT AND SHARP LOW LEVEL TROF
SHIFTING E...WILL RETAIN LIKELY POPS SPREADING E ACROSS THE AREA
TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 548 AM EDT TUE AUG 6 2013
AMPLIFIED UPPER AIR PATTERN PERSISTS THROUGH THE UPCOMING WEEKEND
AND LIKELY INTO NEXT WEEK AS WELL. MEAN TROUGHING DOMINATES MUCH OF
EASTERN CANADA ACROSS THE GREAT LAKES. PRIMARY RESULT OF THIS
PATTERN WILL BE CONTINUATION OF COOLER THAN NORMAL TEMPERATURES
THROUGH AT LEAST MID AUGUST ACROSS UPPER GREAT LAKES REGION. TO
START OUT ON WEDNESDAY...MAIN FEATURES ALOFT ARE CLOSED OFF UPPER
LOW CENTERED ALONG MANITOBA AND NORTHERN ONTARIO BORDER...SHARP WEST
TO EAST RIDGE OVER FAR NORTHERN CANADA AND A DOUBLE BARRELED TROUGH
EXTENDING FROM THE NORTH POLE SOUTHWEST ACROSS ALASKA AND TO THE
NORTHERN PORTIONS OF PACIFIC OCEAN. NOT A WHOLE LOT OF CHANGE WRT
LOCATIONS OF SAID FEATURES THROUGH THE LONG TERM. ONLY THING THAT
DOES CHANGE IS UPPER LOW OVER ONTARIO SLIDES ACROSS QUEBEC THIS
WEEKEND AS STRONGER JET ENERGY BECOMES PLACED OUT AHEAD OF THE
TROUGH...KEEPING IT MORE PROGRESSIVE. MAIN CHANCE OF RAIN IN THIS
PATTERN WILL BE RIGHT OFF THE BAT ON WEDNESDAY MORNING OVER EAST
HALF OF CWA AS COLD FRONT MOVES THROUGH REGION. ADDITIONAL CHANCES
OF RAIN POSSIBLE THURSDAY NIGHT INTO FRIDAY AS SECONDARY LOW PRESSURE
SYSTEM AND COLD FRONT CROSS THE AREA. GENERALLY LOOKS QUIET THROUGH
THE WEEKEND...BUT COOL. NEXT CHANCE OF RAIN PROBABLY ARRIVES LATER
SUNDAY NIGHT INTO MONDAY AS SHORTWAVES DROP ACROSS AREA IN NW FLOW
ALOFT.
COLD FRONT SHOULD BE OVER CNTRL UPR MICHIGAN TO START THE DAY ON
WEDNESDAY...QUICKLY HEADING EAST TO AROUND ERY BTWN 15Z-18Z. NAM
STILL ON THE FAST SIDE...WHILE ECMWF IS SLOWEST. COMPROMISE SOLN
WITH FRONT IS THE GFS/GEM-REGIONAL AS WELL AS NCEP WRF-ARW/NMM.
MAJORITY OF WIDESPREAD SHRA/TSRA WILL BE ALONG AND AHEAD OF FRONT
IN WARM AIR ADVECTION REGIME. GOING FCST LOOKS PRETTY GOOD.
CHANGES TO POPS ON WEDNESDAY WITH FROPA PRETTY MINIMAL. KEPT
LIKELY POPS OVR FAR EAST THROUGH 15Z...THEN TRIMMED BACK QUICKLY
WITH ARRIVAL OF STRONG MID-LEVEL DRYING AND AS PRIMARY H85 MOISTURE
ADVECTION IS EAST OF CWA. SOUNDINGS INDICATE LINGERING LOW-LEVEL
MOISTURE BEHIND COLD FRONT THAT COULD LEAD TO BRIEF PERIOD OF LGT
RAIN/DRIZZLE IN THE MORNING FOR AREAS NEAR LK SUPERIOR.
EVENTUALLY...BLYR BECOMING MIXED ALONG WITH NEGATIVE SFC-H85 THETA-E
ADVECTION WILL SHUT DOWN ANY LINGERING PRECIP BY MIDDAY. HAVE NO
POPS AFTER 18Z WHICH WAS A BIT OF A CHANGE COMPARED TO PREVIOUS
FCST. BKN CU/SC DECK MAY REMAIN LONGER THAN THIS...BUT EVEN THAT
SHOULD TEND TO MIX OUT TO PARTLY CLOUDY SKIES BY MID-LATE AFTN.
TEMPS TRICKY WITH FROPA AS 925-850MB TEMPS JUST AHEAD OF FRONT ARE
PRETTY WARM. FIGURING OUT HOW THE WARM AIR BALANCES BTWN COOLING
FROM CLOUDS/PRECIP IS MAIN HURDLE. WILL GO FOR MAX TEMPS TOPPING OUT
IN THE LOW 70S...WARMEST SOUTH CENTRAL. TEMPS ALONG LK SUPERIOR
COULD RISE EARLY ON...BUT THEN FALL BACK IN THE AFTN WITH INCREASING
ONSHORE FLOW. SHOULD BE ESPECIALLY NOTABLE NEAR MQT-P53. FOG THAT IS
DEVELOPING ACROSS LK SUPERIOR CURRENTLY MAY GET SHOVED ONSHORE TOO
FOR A WHILE.
SFC HIGH RIDGES IN FROM CANADIAN PRAIRIE PROVINCES WEDNESDAY NIGHT
INTO THURSDAY AHEAD OF NEXT COLD FRONT. H85 WINDS STAY ONSHORE ALL
NIGHT...BUT LOWEST LEVEL WINDS THROUGH 900MB BECOME LESS
SO...ALLOWING POTENTIAL FOR TYPICAL COOL SPOTS INLAND FROM THE GREAT
LAKES TO SEE TEMPS FALL INTO THE LOWER 40S. LIGHT GRADIENT WINDS ON
THURSDAY ALLOWS IN LIGHT LAKE BREEZES ALONG BOTH SUPERIOR AND
MICHIGAN. AWAY FM LOCAL COOLING THOUGH...TEMPS SHOULD BOUNCE BACK
INTO AT LEAST THE LOWER 70S MOST AREAS GIVEN H85 TEMPS WARMER THAN
+10C. THICKENING MID CLOUDS /H6-H5/ FOR WEST HALF BY AFTN AS WARM
AIR ADVECTION DEVELOPS AHEAD OF THE COLD FRONT. GFS HAS SHOWED
STEADY TREND IN BACKING OFF QPF INTO WESTERN TIER. USED A BLEND OF
MORE CONSISTENT ECMWF AND THE DRIER TRENDING GFS. RESULT WAS SOME
LOWER CHANCE POPS FOR WESTERN LK SUPERIOR/ISLE ROYALE ON NOSE OF
H85-H7 MOISTURE ADVECTION. AS SFC LOW SPINS OVER NORTHERN ONTARIO
THE COLD FRONT WILL SLOWLY SINK NORTH TO SOUTH ACROSS LK SUPERIOR
ON THURSDAY NIGHT. BEST CHANCE FOR SHRA/ISOLD TSRA WILL BE OVR LK
SUPERIOR DUE TO H85 TEMP ADVECTION/WEAK LOW-LEVEL JET AND SOME
LOW-LEVEL FRONTAL CONVERGENCE. TEMPS WILL BE ON THE MILD SIDE
AGAIN WITH SOUTH WINDS/WARM AIR ADVECTION AHEAD OF FRONT. COLD
FRONT WORKS ACROSS UPR MICHIGAN ON FRIDAY...SO WILL KEEP WITH
SOME LOWER CHANCE POPS. COOLING BEGINS ON FRIDAY...ESPECIALLY NEAR
LK SUPERIOR. INLAND...TEMPS MAY END UP ONLY A COUPLE DEGREES COOLER
THAN THURSDAY.
STRONG DRYING BEHIND FRONT FOR FRIDAY NIGHT AND SATURDAY. JUST SOME
SCT CU SHOULD DEVELOP DURING PEAK HEATING ON SATURDAY. H85 TEMPS
ONLY UP TO +6C WITH STRONGER ONSHORE FLOW WILL LEAD TO A COOL DAY
BY AUGUST STANDARDS WITH READINGS IN THE UPPER 50S/NEAR 60 ALONG LK
SUPERIOR AND MAYBE REACHING 70 DEGREES IN THE FAR SOUTH CENTRAL NEAR
MNM. 60S ELSEWHERE...WHICH IS AT LEAST 10 DEGREES BLO NORMAL.
NOT MUCH IN WAY OF CHANGES TO REST OF CONSENSUS GRIDS FOR EXTENDED.
SLIGHT CHANCE POPS FOR SUNDAY...THOUGH THESE ARE BIASED BY A LATEST
GFS WHICH TRENDED MUCH WETTER FOR PARTS OF CWA COMPARED TO PREVIOUS
RUNS. ECMWF INDICATES SMALL CHANCES OF INSTABILITY SHRA/TSRA AS
ANOTHER STRONGER WAVE OR TWO /CURRENTLY WITHIN THE LARGER TROUGH FM
ALASKA TO THE NORTH POLE/ DROPS ACROSS UPPER LAKES. POCKET OF STEEPER
MID-LEVEL LAPSE RATES WOULD JUSTIFY AT LEAST A MENTION OF TSRA DURING
PEAK HEATING OF SUNDAY AFTN LINGERING INTO SUN EVENING. SIMILAR SETUP
FOR MONDAY THOUGH BY THAT TIME BETTER FORCING IS SLIDING EAST AND
SOUTH OF LK SUPERIOR REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 739 AM EDT TUE AUG 6 2013
ABUNDANT LOW-LEVEL MOISTURE HAS RESULTED IN LIFR CONDITIONS AT
KIWD/KCMX/KSAW EARLY THIS MORNING. DAYTIME HEATING WILL WORK TO
RAISE/SCATTER OUT THE STRATUS AND DISSIPATE FOG. EXPECT ALL
TERMINALS TO BE VFR EARLY THIS AFTN...IF NOT SOONER. AS INSTABILITY
BUILDS THIS AFTN...ISOLD/SCT SHRA/TSRA SHOULD DEVELOP OVER PARTS OF
UPPER MI. KSAW PROBABLY HAS THE BEST CHC OF SEEING SOME PCPN AS LAKE
BREEZE WILL HELP FOCUS SHRA ACTIVITY IN CNTRL UPPER MI. FOR NOW...
INCLUDED VCSH IN THE AFTN. COLD FRONT WILL MOVE INTO UPPER MI
TONIGHT...BRINGING A PERIOD OF SHRA/TSRA AND A RETURN TO MVFR AND
POSSIBLY IFR CONDITIONS. ONCE FRONT PASSES...UPSLOPE FLOW AT
KIWD/KCMX WILL RESULT IN LIFR CONDITIONS REDEVELOPING AT THOSE
TERMINALS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 548 AM EDT TUE AUG 6 2013
LIGHT WINDS THROUGH MUCH OF TONIGHT THEN WINDS WILL KICK UP AS COLD
FRONT CROSSES LK SUPERIOR LATE TONIGHT THROUGH WEDNESDAY MORNING. NW
WINDS BEHIND COLD FRONT MAY REACH 20-25 KTS IN GUSTS. SHOWERS AND
STORMS LIKELY WITH THE FRONTAL PASSAGE. SHIP REPORTS INDICATE FOG
HAS FORMED OVERNIGHT WITH ARRIVAL OF MOIST AIRMASS. EXPECT THE FOG
TO CONTINUE UNTIL WEDNESDAY AFTERNOON WHEN DRIER AIR SCOURS OUT THE
FOG. WINDS DIMINISH TO LESS THAN 20 KTS WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT WITH HIGH PRESSURE OVERHEAD. STRONGER W-NW WINDS
POSSIBLE FRIDAY AND FRIDAY NIGHT AS ANOTHER COLD FRONT CROSSES
LAKE SUPERIOR FROM NORTH TO SOUTH. GUSTS COULD REACH OVER 25 KTS.
WINDS DIMINISH TO LESS THAN 20 KTS FOR REST OF WEEKEND WITH WEAKER
PRESSURE GRADIENT BY THAT TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED
NWS SPRINGFIELD MO
640 AM CDT Tue Aug 6 2013
...SERIOUS FLASH FLOODING SITUATION CONTINUES ACROSS PORTIONS OF
TEXAS AND PULASKI COUNTIES...
.MESOSCALE DISCUSSION...
Issued AT 639 AM CDT TUE AUG 6 2013
Low level jet continues to veer and moisture transport remains
focused from central Missouri through the eastern Ozarks and into
south central Missouri. Some good news is that there has been a
weakening trend to this activity, especially in the areas hardest
hit in Pulaski and Texas counties. Could still see an additional
half inch of rain or so, but the heaviest rain rates have come to
an end.
Latest radar trends suggest an orderly west to east end to the
precipitation and will update timing shortly. Forecast for the
afternoon looks good at this point. Should see at least partial
clearing with a warm/humid afternoon on tap. Isolated to widely
scattered pulse thunderstorm redevelopment remains plausible this
afternoon.
&&
.SHORT TERM...(Today and Tonight)
ISSUED AT 349 AM CDT TUE AUG 6 2013
Very serious flooding situation unfolding across the area this
morning. A band of thunderstorms producing heavy rainfall has set
of up from roughly the Lake of the Ozark area southeastward
through portions of Laclede/Pulaski counties and into the northern
half of Texas county. Radar estimates vary a bit, but given
rainfall rate observations from the past several nights, as much
as 8" of rain has fallen in spots.
This band of rainfall will be the primary concern this morning. A
decaying line of storms entering from the west has produced a
large swath of moderate rain. Rainfall amounts are more modest
with a general half inch to one inch of rainfall over a longer
duration, with embedded pockets of up to two inches of rainfall.
The biggest concern for this morning is that band of torrential
rainfall from central Missouri into the eastern Ozarks and the
extreme flooding risk. Looking at the HRRR and other short range
models, this band of rainfall will not move much through day
break. With hourly rainfall rates between one and two inches, a
bad situation will only get worse.
Rain will gradually end from west to east during the mid to late
morning hours. Like yesterday some clearing is expected and a warm
and humid afternoon is in store. Instability will quickly increase
during the afternoon and additional isolated to widely scattered
thunderstorms will be possible across the entire area. There will
be a limited risk for severe with this activity, with hail to the
size of quarters and localized damaging wind gusts. This activity
will likely persist into the evening in a widely scattered
fashion. Then attention will turn to a complex of thunderstorms
develop to our north/northwest. This will approach the area from
the northwest overnight tonight. In addition, much like the past
few nights, will need to watch for low level jet interaction with
any lingering boundaries. This activity will be possible just
about anywhere across the outlook area. The airmass remains
extremely moist, and flash flooding will once again be a major
concern.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 349 AM CDT TUE AUG 6 2013
The forecast for midweek into early next week remains complex and
concerning. Northwest flow aloft will keep our region in the
atmospheric battleground, and multiple rounds of showers and
thunderstorms remain possible. There is moderate confidence in
another round of heavy rainfall Wednesday night into Thursday. As
a result, the Flash Flood Watch will be extended into Thursday
morning.
The medium range models do offer a glimmer of hope for the weekend
and the pattern briefly deamplifies and the atmospheric
battleground shifts just to the west. Tough to get to confident in
this solution given the persistent upper level pattern that has
been in place. One can certainly hope, though.
The bottom line is that more rounds of rain will be possible.
Temperatures will be at or below average (depending on cloud
coverage and rain).
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
ISSUED AT 639 AM CDT TUE AUG 6 2013
Rainfall is exiting from west to east out of the JLN/SGF/BBG
aerodromes. VFR conditions are expected today with gradual
clearing of mid/high deck expected. Will need to monitor for
isolated to widely scattered thunderstorm development during the
mid/late afternoon hours. Confidence is not high enough to include
at this point. Will also be monitoring for another round of
thunderstorms tonight.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH through Thursday morning FOR MOZ055>058-
066>071-077>083-088>098-101>106.
KS...FLASH FLOOD WATCH through Thursday morning FOR KSZ073-097-101.
&&
$$
MESOSCALE...Gagan
SHORT TERM...Gagan
LONG TERM...Gagan
AVIATION...Gagan
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
631 AM CDT TUE AUG 6 2013
.SHORT TERM...(Today through Wednesday)
Issued at 307 AM CDT TUE AUG 6 2013
Large MCS continues to interact with synoptic boundary arcing from
west central Missouri southeast through the Ozarks. Based on 00Z
soundings, convective outflow boundary should be more than sufficient
forcing to easily overturn the entire warm sector air mass as well as
the region through about 50 miles north. This sharp delineation has
been well handled by the HRRR and NSSL WRF runs, and takes the
northern extent of the thunderstorms to roughly the MO river from
Kansas City metro eastward. Thunderstorm cloud tops have continued
to be in the -75 to -80C range with prolific lightning counts. This
would suggest that despite the rich boundary layer moisture, rainfall
efficiency is not as high as it could be. Nonetheless, 1-2"/hr rates
are almost certain in the heavier cells, and there may be some
tendency for slower storm movement/propagation where the outflow
boundary becomes W-E oriented along the nrn edge of the convection.
80-100% POPs generally carried along and south of the MO river
(slightly more NW- SE oriented) with a rapid decrease further north.
Given the short term setup, while we definitely need the rain around
Kansas City, mesoscale influences suggest this is also the most
likely region for flooding through the next 3-4 hours if conceptual
evolution materializes.
Elsewhere, areas of light fog are expected along the periphery of the
MCS cloud shield where subsidence will work in concert with more
efficient boundary layer cooling and high antecedent moisture
content.
MCS (if not MCC designated) should gradually exit the CWA to the
southeast this morning as the low level jet veers, with convective
debris cirrus lingering through the morning. Like yesterday, most
aggressive warming will occur during the afternoon hours. Given the
very stagnant air mass in place, will introduce haze into the
forecast, coupling with otherwise very sultry conditions expected as
dewpoints climb into the middle 70s. Other than a rogue pulse
thunderstorm or two during the afternoon along a residual boundary,
expect the region to be fairly quiet between 15-00Z.
By evening, a disturbance currently producing active deep convection
over SW South Dakota will reach far NW MO. Despite model variances,
there appears to be an overall suggestion that at least scattered
thunderstorms will develop and/or move into NW MO early this evening,
possibly growing upscale overnight as this activity moves southeast.
SPC highlights the area with a broad slight risk overnight for wind
damage potential. Given some modest increase/linearity to the
700-500mb flow, certainly cannot rule out some storm organization.
This system should also clear the region by late morning, leaving a
hazy, warm and very humid day again on Wednesday.
.LONG TERM...(Thursday through Monday)
Issued at 307 AM CDT TUE AUG 6 2013
Remnant energy lifting northward out of the Baja California
Peninsula and into the Central Plains on Thursday will provide a
reasonable chance for fairly widespread rains across the lower
Missouri river valley. By Thursday morning ECMWF/GFS both suggest
increased troughing over the central Rockies, allowing for southwest
flow to move into the Plains. Strong warm advection ahead of this
wave of energy may be strong enough to force baroclinic zone which
has been stuck to the south of the CWA northward during the day. As
this upper wave ejects eastward Thursday night into Friday, fairly
pronounced mid-level lift provided by PVA and an enhanced upper jet
streak should keep PoPs high overnight as several rounds of showers
and thunderstorms will be possible.
High pressure is expected to sink southward into the central US on
Friday, leading to dry conditions for the first half of the weekend.
Increased troughing off the West Coast combined with fairly
progressive zonal flow over the Nation`s midsection will lead to
lower forecast confidence by early next week. Several waves of
energy may again eject eastward out of this trough, but timing of
these features remains too problematic to target any one time period
for higher PoPs.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
Issued at 628 AM CDT TUE AUG 6 2013
Convective complex has exited east of the STJ-MCI-MKC terminals
early this morning, however foggy conditions persist to the north
and east with IFR/local LIFR expected to improve aft 13Z.
For today, high clouds should burn off by mid morning. However, with
stagnant airmass in place, haze aloft will continue to become an
increase concern. VFR conditions to continue otherwise with lgt/vrb
winds becoming southeast at 8-10 knots.
Models very consistent with developing a complex of strong to severe
thunderstorms across IA/NE later this afternoon (possibly an
extension of ongoing activity near Omaha), and pushing it quickly
southward this evening. Best guess is 03-05Z across the terminals,
with strong wind gusts and torrential rainfall potentially impacting
late evening arrival rates.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Bookbinder
LONG TERM...Dux
AVIATION...Bookbinder
AREA FORECAST DISCUSSION
NWS GLASGOW MT
924 AM MDT TUE AUG 6 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
AREAS IN THE SOUTHWEST PART OF THE CWA ARE MOSTLY CLEAR...SO
REDUCED CLOUD COVER AND POPS IN THAT AREA FOR THIS MORNING FOR THIS
UPDATE. THE HRRR AND OTHER MODELS HAVE PRECIPITATION DEVELOPING
AFTER 18Z OVER THE NORTHEAST 2/3RDS OF THE CWA...AND THIS APPEARS
TO BE WELL-REPRESENTED IN THE CURRENT FORECAST. VERY MARGINAL
INSTABILITY SHOULD KEEP ANY THUNDERSHOWER ACTIVITY ON THE WEAK SIDE. MARTIN
PREVIOUS DISCUSSION...
SYNOPTIC SET UP... A LARGE CLOSED COLD CORE LOW IS
CENTERED OVER NORTHERN MANITOBA AND ITS INFLUENCE SPREADS FAR BACK
ACROSS THE CANADIAN PRAIRIES AND NORTHERN US HIGH PLAINS. TO THE
SOUTH A LARGE HIGH PRESSURE HEAT DOME STRETCHES FROM THE SOUTHERN
PLAINS TO THE FOUR CORNERS INTO THE LOWER INTERMOUNTAIN WEST.
NORTHEAST MONTANA LIES IN ZONAL FLOW BETWEEN THESE TWO LARGE
FEATURES. TO THE WEST A RIDGE RUNS UP BRITISH COLUMBIA WITH A
BROAD WEAK TROUGH OFF THE COAST OF CANADA AND THE US.
TODAY THROUGH TONIGHT... THE COLD AIR ACROSS THE REGION IS
ANTICIPATED TO MOVE OFF TO THE WEST DURING THE MORNING HOURS.
WHILE THE RIDGE ACROSS THE INTERMOUNTAIN WEST IS EXPECTED TO SURGE
UP INTO THE BRITISH COLUMBIA RIDGE... RE-ROUTING SLOWLY TO
NORTHWEST FLOW AND WARMING THE AREA SLIGHTLY. A WEAK SHORTWAVE IS
ANTICIPATED TO RIDE AROUND THE MANITOBA LOW AND WILL BRIEFLY BRUSH
THE NORTHEAST CORNER OF THE CWA DURING THE AFTERNOON HOURS.
CAPE WITH THIS SYSTEM/SHORTWAVE COULD REACH UP TO 1000 J/KG DURING THE
AFTERNOON WITH WEAK SHEAR. CAPE ALSO LOOKS VERY THIN ALLOWING FOR
WEAKENING DRY AIR ENTRAINMENT EFFECTS. THIS COULD PRODUCE SOME
SMALL HAIL BUT WILL HAVE A HARD TIME BECOMING SEVERE. IN
ADDITION... CAPE LOOKS VERY MUCH SURFACE BASED. SO... AS THE SUN GOES
DOWN THUNDERSTORMS WILL RAPIDLY DIE OFF LEADING TO A FAIRLY DRY
OVERNIGHT PERIOD.
WEDNESDAY THROUGH THURSDAY... TEMPERATURES WILL BRIEFLY RISE AGAIN
WEDNESDAY. AFTER THAT... A CONFIDENCE PROBLEM ARISES WITH TWO
SOLUTIONS.,. ONE BEING THE GFS/NAM AND THE OTHER BEING THE
GEM/EC. GFS/NAM SOLUTION BRINGS A SHORTWAVE THROUGH WITH A VERY
SHARPENED COLD FRONT AROUND MIDNIGHT. THE EC/GEM SOLUTION BRINGS
THE SHORTWAVE THROUGH... BUT DELAYS THE FRONT ABOUT 12 TO 24 HOURS
LATER BY LEAVING IT VERY DIFFUSE. BOUNDARY OR NOT... CHANCES FOR
POPS SHOULD SHOOT UP A BIT THROUGH THESE PERIODS WITH THE
SHORTWAVE. THE QUESTION IS THE EXTENT TO WHICH IT SHOOTS UP BEING
DEPENDENT UPON THE FRONT. GAH
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
FORECAST THROUGH THE END OF THE WEEK WILL BE INFLUENCED BY THE LINGERING
EFFECTS OF THE STRONG HUDSON BAY LOW. UPPER RIDGE BUILDING NORTH
ALONG THE ROCKIES WILL BE THE MAIN PLAYER FOR EARLY NEXT WEEK.
MODELS SLIPPING OUT OF AGREEMENT REGARDING THE HUDSON BAY LOW
AFTER IT DROPS INTO CENTRAL MANITOBA. ECMWF MOVES IT EAST FASTER
THEN THE GFS BUT LEAVES A PORTION BEHIND IN SASKATCHEWAN THURSDAY
NIGHT. EC CURRENTLY NOT INDICATING MUCH INFLUENCE ON THE SENSIBLE
WEATHER WITH THIS FEATURE BUT THAT COULD CHANGE. NORTHWEST FLOW
INTO EASTERN MONTANA ALONG WITH CANADIAN HIGH PUSHING INTO THE
NORTHERN PLAINS SUGGEST A SHORT PERIOD OF DRIER WEATHER BUT AS
SHORTWAVES BEGIN EJECTING OUT OF THE TROF ALONG THE WEST COAST AND
THROUGH THE NORTHERN ROCKIES RIDGE...WILL SEE A RETURN OF
THUNDERSTORM CHANCES.
AFTER A COOL START TO THE EXTENDED PERIOD WITH THE PROXIMITY OF
THE HUDSON BAY LOW...TEMPERATURES WILL WARM THROUGH THE WEEKEND AS
UPPER RIDGE PUSHES OUT INTO THE NORTHERN PLAINS. EBERT
&&
.AVIATION...
MOSTLY VFR TODAY...EXCEPT FOR MORNING LOW STRATUS IN THE MISSOURI
AND YELLOWSTONE RIVER VALLEYS AFFECTING KOLF AND KSDY WITH MVFR
CEILINGS.
AN UPPER LEVEL RIDGE WEST OF THE DIVIDE AND A STRONG LOW PRESSURE
SYSTEM OVER HUDSON BAY WILL MAINTAIN NORTHWEST FLOW ALOFT FOR
NORTHEAST MONTANA. THESE WEATHER SYSTEMS HAVE PLACED A STATIONARY
COLD FRONT ACROSS THE LOCAL AREA THAT WILL BE THE FOCUS OF
INTERMITTENT RAIN SHOWERS AND GENERAL THUNDERSTORMS THIS
AFTERNOON THROUGH WEDNESDAY. BRIEF PERIODS OF LESS THAN VFR
CONDITIONS ARE POSSIBLE WITH ANY THUNDERSTORM THAT DEVELOPS.
A SURFACE TROUGH ACROSS THE DAKOTAS WILL MAINTAIN NORTHWEST
SURFACE WIND THIS MORNING THAT WILL VEER TO THE NORTH BY
AFTERNOON. EXPECT WIND SPEED OF AROUND 10KT TO 20KT. WIND WILL
BECOME LIGHT AND VARIABLE TONIGHT AND WEDNESDAY MORNING. SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1017 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE MID-ATLANTIC COAST WILL MOVE FARTHER OUT TO
SEA THIS WEEK...BUT A RIDGE AXIS WILL REMAIN ACROSS NORTH CAROLINA
THROUGH WEDNESDAY. AS WINDS GRADUALLY TURN MORE SOUTHERLY HEAT AND
HUMIDITY WILL RETURN LATE IN THE WEEK. A PIEDMONT TROUGH WILL
DEVELOP INLAND FRIDAY AND SATURDAY AHEAD OF A COLD FRONT THAT MAY
APPROACH FROM THE NORTH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM TUESDAY...ANOTHER COOL DAY ON TAP ACROSS THE EASTERN
CAROLINAS AS CANADIAN HIGH PRESSURE DRIFTING OFFSHORE THE
MID-ATLANTIC CONTINUES ITS INFLUENCE OVER THE REGION. AN UPPER LEVEL
IMPULSE MOVING THROUGH THE EASTERN CONUS LONGWAVE TROUGH MAY BRING
SOME LIGHT RAIN SHOWERS TO THE AREA LATER THIS MORNING INTO THE AFTN.
WEAKENING COLD FRONT HAS CRUISED TO JUST SOUTH OF THE
FLORIDA-GEORGIA LINE...WITH CANADIAN HIGH PRESSURE KEEPING THE HEAT
OF THE SUMMER AT BAY. TEMPS TODAY WILL STRUGGLE AGAIN TO SEVERAL
DEGREES BELOW NORMAL FOR EARLY AUGUST...REACHING ONLY THE LOW 80S
ACROSS THE NORTHERN TIER...MID/UPR 80S FAR SOUTH. WHILE WINDS WILL
SLOWLY BECOME MORE S/SE TODAY AS HIGH PRESSURE RETREATS FURTHER
OFFSHORE...THIS CONTINUES TO ADVECT VERY DRY AIR INTO THE CWA SINCE
STREAMLINES SUGGEST CANADIAN AIR-MASS ORIGIN, AS NOTED BY PREVIOUS
FORECASTER. THIS CONTINUED DRY AIR IS IMPORTANT TO NOTE...SINCE IT
WILL HAVE CONSIDERABLE IMPACT ON PRECIP CHANCES THROUGH THIS EVE.
AN UPPER IMPULSE NOTED ON WV IMAGERY IS PRODUCING AN AREA OF LIGHT
TO MDT RAIN SHOWERS...CURRENTLY JUST WEST OF THE ILM CWA. THIS
SHORTWAVE WILL MOVE NEARLY OVERHEAD THIS AFTN...EXITING OFFSHORE BY
4PM THIS EVE. FORECAST PROFILES SUGGEST INCREASING MID-LEVEL
SATURATION FROM ELIZABETHTOWN...TO FLORENCE...AND POINTS WEST THIS
AFTN...WHILE THE COASTAL REGION REMAINS QUITE DRY. THIS POINTS TO
THE POTENTIAL FOR A PERIOD OF SHOWERS...FOCUSED MAINLY ACROSS THE
WESTERN HALF OF THE CWA...WITH PRECIP ERODING SLOWLY AS THE
SHORTWAVE TRAVERSES EASTWARD. THIS IS ALREADY EVIDENT ON
REFLECTIVITY...SO INHERITED LOW-CHC ACROSS THE NW TIER REMAINS
UNCHANGED...BUT DID EXPAND SCHC POP SE SLIGHTLY TO ACCOUNT FOR
LATEST HRRR WHICH HAS PERFORMED WELL THIS MORNING. EVEN PLACES THAT
DO NOT RECEIVE RAINFALL TODAY WILL SEE INCREASING MID LEVEL
CLOUDINESS.
TONIGHT...RENEWED DRYING WILL OCCUR WITHIN THE COLUMN...BRINGING AN
END TO ANY PRECIP CHANCES FOR THE PERIOD. LIGHT SOUTHERLY WINDS WILL
PERSIST HOWEVER...SO EVEN AS SKY CONDITIONS IMPROVE...RADIATIONAL
COOLING WILL BE SOMEWHAT INHIBITED. MINS WILL BE A DEGREE OR TWO
WARMER THAN LAST NIGHT...FALLING TO 70-73 AT THE COAST...67-70
INLAND.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...HIGH PRESSURE WILL SHIFT FARTHER OFF THE
EAST COAST THROUGH THE PERIOD. COASTAL CAROLINAS WILL BASICALLY BE
IN A DEEPER WARMER AND MOISTER RETURN FLOW ON THE WESTERN
PERIPHERY OF THE ATLANTIC RIDGE BY THE END OF THE PERIOD. THE FLOW
WILL SHIFT FROM SE ON WED TO S-SW BY FRI MORNING. ALTHOUGH
DEWPOINT TEMPS WILL BE CREEPING BACK UP TOWARD 70 ON WED...THE
ATMOSPHERIC COLUMN WILL REMAIN RELATIVELY DRY WITH PCP WATER
VALUES AROUND 1.5 INCHES. LOOKS LIKE A MINOR PERTURBATION FROM THE
WEST IN THE MID LEVEL FLOW WILL REACH THE COAST OVERNIGHT WED AND
MAY SEE SOME CLOUDS AND AN ISOLATED SHOWER OR TWO MOVING ACROSS
THE COASTAL WATERS AND POSSIBLY JUST ALONG THE COAST.
OTHERWISE...EXPECT PLENTY OF SUNSHINE FOR WED. BY THURS A DEEPER
SOUTHERLY FLOW WILL CONTINUE TO FEED MOISTURE INTO THE AREA
BRINGING PCP WATER VALUES UP TO 1.75 INCHES...BUT MID TO UPPER
RIDGE WILL NUDGE INTO THE AREA FROM THE EAST. OVERALL EXPECT CU
BUILDUP IN THE AFTERNOON AND ONLY LOCALIZED CONVECTION MAINLY
ALONG THE SEA BREEZE BOUNDARY WITH DRY AIR AND SUBSIDENCE ALOFT TO
PREVENT MORE WIDESPREAD ACTIVITY. TEMPS WILL RUN SLIGHTLY BELOW
NORMAL ON WED WITH MID 80S MOST PLACES AND WILL HEAD BACK TO
NORMAL ON THURS WITH READINGS NEAR 70 FOR LOWS AND CLOSER TO 90
FOR HIGHS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...SOUTHERLY RETURN FLOW WILL PERSIST AROUND
ATLANTIC HIGH PRESSURE AS MID TO UPPER RIDGE BUILDS OVER THE AREA
FROM THE SOUTHEAST FRI INTO SAT. THE SOUTHERN EXTENT OF A COLD
FRONT WILL REACH THE CAROLINAS BY SATURDAY BUT WILL END UP
STALLING WITH PIEDMONT TROUGH INLAND AND SEA BREEZE BOUNDARY BEING
THE MAIN FEATURES TO FOCUS ANY CONVECTION ON BOTH FRI AND
SATURDAY. THE H5 RIDGE UP TO 595 DEM JUST OFF THE COAST FRI INTO
EARLY SAT SHOULD PROVIDE ENOUGH SUBSIDENCE TO KEEP SHOWER ACTIVITY
LIMITED TO MAINLY INLAND AREAS. BY SATURDAY THE RIDGE GETS
SUPPRESSED FARTHER SOUTH AS MID TO UPPER TROUGH BEGINS TO DIG DOWN
THE EAST COAST WITH SFC TROUGH/FRONT SHIFTING SOUTHEAST AND CLOSER
TO THE COAST. BY LATE SUNDAY THROUGH TUESDAY...A MUCH DEEPER
COLUMN OF MOISTURE WILL BE PRESENT WITH PCP WATER VALUES UP ABOVE
2 INCHES. OVERALL EXPECT INCREASING CHC OF MORE WIDESPREAD
CONVECTION INTO EARLY NEXT WEEK WITH GREATER INSTABILITY AND
MOISTURE IN THE ATMOSPHERE AS DECENT UPPER LEVEL SUPPORT.
DEWPOINT TEMPS WILL BE BACK UP IN THE 70S WITH OVERNIGHT LOWS
IN THE MID 70S AND DAY TIME HIGHS REACHING INTO THE 90S. CLOUDS
AND PCP MAY KEEP VALUES SLIGHTLY LOWER EACH AFTERNOON INTO EARLY
NEXT WEEK.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...A COUPLE OF WEAK DISTURBANCES COMING OVER THE MOUNTAINS
WILL GIVE THE NORTHWESTERN PORTION OF THE CWA A CHANCE FOR SHOWERS
THROUGH THE MORNING HOURS. MUCH OF THE PRECIPITATION WILL COME OUT
OF MID CLOUD AND WILL LIKELY STAY VIRGA. WILL KEEP VCSH IN THE LBT
TAF...OTHERWISE PRECIP FREE FOR THE REMAINDER OF THE REGION. MAINLY
A MID CLOUD CEILING THROUGHOUT THE REGION THROUGH THE AFTERNOON
HOURS WITH A SOUTHEAST WIND...STRONGEST NEAR THE COAST. MUCH OF THE
CLOUDS DISSIPATE THROUGH THE OVERNIGHT HOURS...BUT PROBABLY TOO DRY
AT THE SURFACE TO ADD FOG.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE WEDNESDAY THROUGH SATURDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 1015 AM TUESDAY...CANADIAN HIGH PRESSURE JUST OFF THE
MID-ATLANTIC COAST WILL CONTINUE TO PUSH SLOWLY AWAY FROM SHORE
THROUGH TONIGHT. WHILE THIS OCCURS...A RIDGE AXIS WILL CONTINUE TO
EXTEND BACK TOWARDS THE EASTERN CAROLINAS...KEEPING THE PRESSURE
GRADIENT LIGHT AND WINDS E/SE AT AROUND 10 KTS. SEAS AT THE LOCAL
BUOYS ARE CURRENTLY ALL 2 FT OR LESS...AND THIS WILL PERSIST THROUGH
THE PERIOD WITH LITTLE CHANGE. WAVES WILL BE FORMED BY A CONTINUED
4-SEC E/SE WIND CHOP AND 10 SEC SE GROUND SWELL.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...RETURN FLOW AROUND ATLANTIC RIDGE OF HIGH
PRESSURE WILL PERSIST THROUGH THE PERIOD. THE FLOW WILL VEER
AROUND FROM SOUTHEAST ON WED BECOMING MORE S-SW ON THURS. THE
WINDS WILL REMAIN AROUND 10 KTS SPIKING UP A BIT EACH AFTERNOON IN
THE SEA BREEZE. THE PERSISTENT ON SHORE PUSH WILL KEEP SEAS AROUND
2 TO 3 FT WITH SHORTER PERIOD WIND WAVES MIXING WITH A LONGER
PERIOD 9 SECOND SE SWELL.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...EXPECT A SOUTH TO SOUTHWEST FLOW TO
CONTINUE THROUGH THE PERIOD AROUND ATLANTIC HIGH. THE WINDS WILL
VEER SLIGHTLY MORE INTO THE WEEKEND AS PIEDMONT TROUGH BECOMES
MORE PRONOUNCED AND COLD FRONT MOVES INTO THE CAROLINAS FROM THE
NORTHWEST OVER THE WEEKEND. THE GRADIENT WILL TIGHTEN BETWEEN INLAND
TROUGH/FRONT AND HIGH PRESSURE OFF SHORE TO PRODUCE WIND 10 TO 15 KTS
THROUGH THE PERIOD. THE INCREASED SOUTHERLY PUSH WILL PRODUCE A
RISE IN SEAS UP CLOSER TO 3 FT THROUGH THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
650 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE MID-ATLANTIC COAST WILL MOVE FARTHER OUT TO
SEA THIS WEEK...BUT A RIDGE AXIS WILL REMAIN ACROSS NORTH CAROLINA
THROUGH WEDNESDAY. AS WINDS GRADUALLY TURN MORE SOUTHERLY HEAT AND
HUMIDITY WILL RETURN LATE IN THE WEEK. A PIEDMONT TROUGH WILL
DEVELOP INLAND FRIDAY AND SATURDAY AHEAD OF A COLD FRONT THAT MAY
APPROACH FROM THE NORTH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM TUESDAY...TWEAKS TO CLOUDS AND POPS ARE THE MAIN FOCUS
OF THIS EARLY MORNING UPDATE...INCORPORATING THE LATEST HRRR MODEL
WHICH SEEMS TO HAVE INITIALIZED FAIRLY WELL. MEASURABLE RAIN CHANCES
ARE HIGHEST TODAY IN THE AREA FROM BENNETTSVILLE THROUGH LUMBERTON
AND ELIZABETHTOWN. THE 00Z ECMWF MOS TEMPERATURES CAME IN VERY CLOSE
TO MY FORECAST HIGHS SO NO SIGNIFICANT CHANGES ARE PLANNED THERE.
PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
UNSEASONABLY DRY AIR AT THE SURFACE IS BEING PROVIDED BY EASTERLY
FLOW AROUND HIGH PRESSURE CENTERED OFF THE MID-ATLANTIC COAST.
ALTHOUGH AN EAST WIND IS NORMALLY QUITE HUMID... LOOKING BACK ALONG
THE STREAMLINES REVEALS THIS AIR HAS CANADIAN ORIGINS JUST A FEW
DAYS AGO. THE COLD FRONT THAT PUSHED ACROSS THE CAROLINAS TWO DAYS
AGO IS STALLED NEAR THE GEORGIA/FLORIDA STATE LINE AND SHOULD WEAKEN
TODAY.
IN THE UPPER LEVELS A LONGWAVE TROUGH REMAINS ACROSS EASTERN NORTH
AMERICA. THERE ARE MULTIPLE SHORTWAVES EMBEDDED WITHIN THE REGION OF
CYCLONIC FLOW ALOFT. THE ONE EXPECTED TO HAVE THE MOST IMPACT ON OUR
WEATHER TODAY IS CURRENTLY OVER THE SOUTHERN APPALACHIANS AND IS
HELPING SUSTAIN SHOWERS AND T-STORMS EARLY THIS MORNING ACROSS THE
WESTERN AND CENTRAL CAROLINAS.
THERE ARE COMPETING FACTORS AT WORK REGARDING HOW HIGH PRECIPITATION
CHANCES WILL BECOME HERE IN THE EASTERN CAROLINAS LATER TODAY. THE
UPPER LEVEL DISTURBANCE WILL MOVE EAST OUT OF THE MOUNTAINS AND
OVERHEAD BETWEEN 11AM AND 2 PM. THERE IS INCREASING MID LEVEL
MOISTURE AND SOME COOLING ALOFT THAT WILL HELP ERODE THE MID-LEVEL
CAPPING OBSERVED ON BOTH THE 00Z MHX AND CHS SOUNDINGS. NEGATIVE
FACTORS WORKING AGAINST PRECIPITATION INCLUDE RESIDUAL DRY AIR BELOW
850 MB THAT WILL KEEP SURFACE-BASED INSTABILITY VERY LOW...AND A JET
STREAK AT 200 MB CENTERED OVER OHIO AND WEST VIRGINIA WHICH PLACES
THE CAROLINAS IN THE RIGHT-EXIT REGION...TYPICALLY ASSOCIATED WITH
UPPER LEVEL CONVERGENCE AND LOWER-TROPOSPHERIC SINKING MOTION. THE
COAST CERTAINLY WILL HAVE THE SMALLEST PRECIPITATION POTENTIAL TODAY
GIVEN OVERWHELMING DRY AIR. I AM FORECASTING ONLY PERIODS OF
CLOUDINESS TO PASS OVERHEAD HERE TODAY. ALONG THE INTERSTATE 95
CORRIDOR (BUT PARTICULARLY AROUND LUMBERTON) THERE ARE INCREASING
CHANCES FOR SHOWERS FORECAST...MAINLY FROM MID MORNING THROUGH EARLY
AFTERNOON AS THE UPPER DISTURBANCE CROSSES THE AREA. DESPITE WARMING
TEMPERATURES IN THE AFTERNOON WITH SOME SUNSHINE...NVA AND INCREASED
SUBSIDENT MOTION BEHIND THE SHORTWAVE SHOULD LEAD TO DIMINISHING
RAIN CHANCES.
THE 00Z GFS IS MUCH MORE BULLISH WITH RAIN CHANCES THAN THE 00Z
NAM...AND WITH ITS ADDITIONAL RAINFALL THE GFS HAS MUCH COOLER
TEMPERATURES FORECAST TODAY COMPARED TO THE NAM. GIVEN CURRENT RADAR
RETURNS ALONG I-85 FROM CHARLOTTE THROUGH GREENSBORO THE GFS IS
PROBABLY CORRECT WITH COVERAGE BUT MAY HAVE PLACED ITS QPF MAXIMUM
TOO FAR SOUTH. MY FORECAST IS FOR 20-30 PERCENT COVERAGE OF SHOWERS
ACROSS DARLINGTON-FLORENCE-DILLON-LUMBERTON-ELIZABETHTOWN...WITH
ONLY A 5-10 PERCENT CHANCE AT THE COAST. HIGHS SHOULD RANGE FROM THE
UPPER 80S FROM FLORENCE AND MARION INTO KINGSTREE...WITH MID 80S
ELSEWHERE.
ALTHOUGH AREAS OF MID LEVEL CLOUDINESS WILL HANG AROUND THROUGH
TONIGHT PRECIPITATION CHANCES SHOULD BE TOO LOW FOR MENTION IN THE
FORECAST. TEMPERATURES WILL MODERATE A LITTLE WITH THE CONTINUING
ONSHORE FLOW...WITH LOWS IN THE UPPER 60S FORECAST INLAND AND LOWER
70S AT THE BEACHES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...HIGH PRESSURE WILL SHIFT FARTHER OFF THE
EAST COAST THROUGH THE PERIOD. COASTAL CAROLINAS WILL BASICALLY BE
IN A DEEPER WARMER AND MOISTER RETURN FLOW ON THE WESTERN
PERIPHERY OF THE ATLANTIC RIDGE BY THE END OF THE PERIOD. THE FLOW
WILL SHIFT FROM SE ON WED TO S-SW BY FRI MORNING. ALTHOUGH
DEWPOINT TEMPS WILL BE CREEPING BACK UP TOWARD 70 ON WED...THE
ATMOSPHERIC COLUMN WILL REMAIN RELATIVELY DRY WITH PCP WATER
VALUES AROUND 1.5 INCHES. LOOKS LIKE A MINOR PERTURBATION FROM THE
WEST IN THE MID LEVEL FLOW WILL REACH THE COAST OVERNIGHT WED AND
MAY SEE SOME CLOUDS AND AN ISOLATED SHOWER OR TWO MOVING ACROSS
THE COASTAL WATERS AND POSSIBLY JUST ALONG THE COAST.
OTHERWISE...EXPECT PLENTY OF SUNSHINE FOR WED. BY THURS A DEEPER
SOUTHERLY FLOW WILL CONTINUE TO FEED MOISTURE INTO THE AREA
BRINGING PCP WATER VALUES UP TO 1.75 INCHES...BUT MID TO UPPER
RIDGE WILL NUDGE INTO THE AREA FROM THE EAST. OVERALL EXPECT CU
BUILDUP IN THE AFTERNOON AND ONLY LOCALIZED CONVECTION MAINLY
ALONG THE SEA BREEZE BOUNDARY WITH DRY AIR AND SUBSIDENCE ALOFT TO
PREVENT MORE WIDESPREAD ACTIVITY. TEMPS WILL RUN SLIGHTLY BELOW
NORMAL ON WED WITH MID 80S MOST PLACES AND WILL HEAD BACK TO
NORMAL ON THURS WITH READINGS NEAR 70 FOR LOWS AND CLOSER TO 90
FOR HIGHS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...SOUTHERLY RETURN FLOW WILL PERSIST AROUND
ATLANTIC HIGH PRESSURE AS MID TO UPPER RIDGE BUILDS OVER THE AREA
FROM THE SOUTHEAST FRI INTO SAT. THE SOUTHERN EXTENT OF A COLD
FRONT WILL REACH THE CAROLINAS BY SATURDAY BUT WILL END UP
STALLING WITH PIEDMONT TROUGH INLAND AND SEA BREEZE BOUNDARY BEING
THE MAIN FEATURES TO FOCUS ANY CONVECTION ON BOTH FRI AND
SATURDAY. THE H5 RIDGE UP TO 595 DEM JUST OFF THE COAST FRI INTO
EARLY SAT SHOULD PROVIDE ENOUGH SUBSIDENCE TO KEEP SHOWER ACTIVITY
LIMITED TO MAINLY INLAND AREAS. BY SATURDAY THE RIDGE GETS
SUPPRESSED FARTHER SOUTH AS MID TO UPPER TROUGH BEGINS TO DIG DOWN
THE EAST COAST WITH SFC TROUGH/FRONT SHIFTING SOUTHEAST AND CLOSER
TO THE COAST. BY LATE SUNDAY THROUGH TUESDAY...A MUCH DEEPER
COLUMN OF MOISTURE WILL BE PRESENT WITH PCP WATER VALUES UP ABOVE
2 INCHES. OVERALL EXPECT INCREASING CHC OF MORE WIDESPREAD
CONVECTION INTO EARLY NEXT WEEK WITH GREATER INSTABILITY AND
MOISTURE IN THE ATMOSPHERE AS DECENT UPPER LEVEL SUPPORT.
DEWPOINT TEMPS WILL BE BACK UP IN THE 70S WITH OVERNIGHT LOWS
IN THE MID 70S AND DAY TIME HIGHS REACHING INTO THE 90S. CLOUDS
AND PCP MAY KEEP VALUES SLIGHTLY LOWER EACH AFTERNOON INTO EARLY
NEXT WEEK.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...A COUPLE OF WEAK DISTURBANCES COMING OVER THE MOUNTAINS
WILL GIVE THE NORTHWESTERN PORTION OF THE CWA A CHANCE FOR SHOWERS
THROUGH THE MORNING HOURS. MUCH OF THE PRECIPITATION WILL COME OUT
OF MID CLOUD AND WILL LIKELY STAY VIRGA. WILL KEEP VCSH IN THE LBT
TAF...OTHERWISE PRECIP FREE FOR THE REMAINDER OF THE REGION. MAINLY
A MID CLOUD CEILING THROUGHOUT THE REGION THROUGH THE AFTERNOON
HOURS WITH A SOUTHEAST WIND...STRONGEST NEAR THE COAST. MUCH OF THE
CLOUDS DISSIPATE THROUGH THE OVERNIGHT HOURS...BUT PROBABLY TOO DRY
AT THE SURFACE TO ADD FOG.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE WEDNESDAY THROUGH SATURDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 630 AM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
CANADIAN HIGH PRESSURE CENTERED OFF THE NEW JERSEY COAST IS
EXTENDING A SURFACE RIDGE AXIS SOUTHWESTWARD INTO EASTERN NORTH
CAROLINA AND CENTRAL SOUTH CAROLINA. ALTHOUGH THE MAIN AREA OF HIGH
PRESSURE WILL MOVE FARTHER OFFSHORE TONIGHT THE RIDGE AXIS WILL
REMAIN IN PLACE. THIS SHOULD KEEP OUR WINDS FROM VEERING AROUND TO
THE SOUTH AS NORMALLY OCCURS WITH A DEPARTING EAST COAST HIGH. EAST
TO SOUTHEAST WINDS 10-15 KNOTS THIS MORNING WILL DIMINISH TO AROUND
10 KNOTS FOR THIS AFTERNOON AND TONIGHT. ALTHOUGH THERE WILL BE AN
INCREASE IN CLOUD COVER THIS MORNING...IT APPEARS SHOWER CHANCES
WILL REMAIN CONFINED TO INTERIOR SECTIONS OF THE CAROLINAS. SEAS
CURRENTLY AVERAGE 2-3 FT AT THE BUOYS WITH SHORT WIND-DRIVEN
PERIODS. LITTLE CHANGE IS FORECAST INTO TONIGHT.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...RETURN FLOW AROUND ATLANTIC RIDGE OF HIGH
PRESSURE WILL PERSIST THROUGH THE PERIOD. THE FLOW WILL VEER
AROUND FROM SOUTHEAST ON WED BECOMING MORE S-SW ON THURS. THE
WINDS WILL REMAIN AROUND 10 KTS SPIKING UP A BIT EACH AFTERNOON IN
THE SEA BREEZE. THE PERSISTENT ON SHORE PUSH WILL KEEP SEAS AROUND
2 TO 3 FT WITH SHORTER PERIOD WIND WAVES MIXING WITH A LONGER
PERIOD 9 SECOND SE SWELL.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...EXPECT A SOUTH TO SOUTHWEST FLOW TO
CONTINUE THROUGH THE PERIOD AROUND ATLANTIC HIGH. THE WINDS WILL
VEER SLIGHTLY MORE INTO THE WEEKEND AS PIEDMONT TROUGH BECOMES
MORE PRONOUNCED AND COLD FRONT MOVES INTO THE CAROLINAS FROM THE
NORTHWEST OVER THE WEEKEND. THE GRADIENT WILL TIGHTEN BETWEEN INLAND
TROUGH/FRONT AND HIGH PRESSURE OFF SHORE TO PRODUCE WIND 10 TO 15 KTS
THROUGH THE PERIOD. THE INCREASED SOUTHERLY PUSH WILL PRODUCE A
RISE IN SEAS UP CLOSER TO 3 FT THROUGH THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
641 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE MID-ATLANTIC COAST WILL MOVE FARTHER OUT TO
SEA THIS WEEK...BUT A RIDGE AXIS WILL REMAIN ACROSS NORTH CAROLINA
THROUGH WEDNESDAY. AS WINDS GRADUALLY TURN MORE SOUTHERLY HEAT AND
HUMIDITY WILL RETURN LATE IN THE WEEK. A PIEDMONT TROUGH WILL
DEVELOP INLAND FRIDAY AND SATURDAY AHEAD OF A COLD FRONT THAT MAY
APPROACH FROM THE NORTH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM TUESDAY...TWEAKS TO CLOUDS AND POPS ARE THE MAIN FOCUS
OF THIS EARLY MORNING UPDATE...INCORPORATING THE LATEST HRRR MODEL
WHICH SEEMS TO HAVE INITIALIZED FAIRLY WELL. MEASURABLE RAIN CHANCES
ARE HIGHEST TODAY IN THE AREA FROM BENNETTSVILLE THROUGH LUMBERTON
AND ELIZABETHTOWN. THE 00Z ECMWF MOS TEMPERATURES CAME IN VERY CLOSE
TO MY FORECAST HIGHS SO NO SIGNIFICANT CHANGES ARE PLANNED THERE.
PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
UNSEASONABLY DRY AIR AT THE SURFACE IS BEING PROVIDED BY EASTERLY
FLOW AROUND HIGH PRESSURE CENTERED OFF THE MID-ATLANTIC COAST.
ALTHOUGH AN EAST WIND IS NORMALLY QUITE HUMID... LOOKING BACK ALONG
THE STREAMLINES REVEALS THIS AIR HAS CANADIAN ORIGINS JUST A FEW
DAYS AGO. THE COLD FRONT THAT PUSHED ACROSS THE CAROLINAS TWO DAYS
AGO IS STALLED NEAR THE GEORGIA/FLORIDA STATE LINE AND SHOULD WEAKEN
TODAY.
IN THE UPPER LEVELS A LONGWAVE TROUGH REMAINS ACROSS EASTERN NORTH
AMERICA. THERE ARE MULTIPLE SHORTWAVES EMBEDDED WITHIN THE REGION OF
CYCLONIC FLOW ALOFT. THE ONE EXPECTED TO HAVE THE MOST IMPACT ON OUR
WEATHER TODAY IS CURRENTLY OVER THE SOUTHERN APPALACHIANS AND IS
HELPING SUSTAIN SHOWERS AND T-STORMS EARLY THIS MORNING ACROSS THE
WESTERN AND CENTRAL CAROLINAS.
THERE ARE COMPETING FACTORS AT WORK REGARDING HOW HIGH PRECIPITATION
CHANCES WILL BECOME HERE IN THE EASTERN CAROLINAS LATER TODAY. THE
UPPER LEVEL DISTURBANCE WILL MOVE EAST OUT OF THE MOUNTAINS AND
OVERHEAD BETWEEN 11AM AND 2 PM. THERE IS INCREASING MID LEVEL
MOISTURE AND SOME COOLING ALOFT THAT WILL HELP ERODE THE MID-LEVEL
CAPPING OBSERVED ON BOTH THE 00Z MHX AND CHS SOUNDINGS. NEGATIVE
FACTORS WORKING AGAINST PRECIPITATION INCLUDE RESIDUAL DRY AIR BELOW
850 MB THAT WILL KEEP SURFACE-BASED INSTABILITY VERY LOW...AND A JET
STREAK AT 200 MB CENTERED OVER OHIO AND WEST VIRGINIA WHICH PLACES
THE CAROLINAS IN THE RIGHT-EXIT REGION...TYPICALLY ASSOCIATED WITH
UPPER LEVEL CONVERGENCE AND LOWER-TROPOSPHERIC SINKING MOTION. THE
COAST CERTAINLY WILL HAVE THE SMALLEST PRECIPITATION POTENTIAL TODAY
GIVEN OVERWHELMING DRY AIR. I AM FORECASTING ONLY PERIODS OF
CLOUDINESS TO PASS OVERHEAD HERE TODAY. ALONG THE INTERSTATE 95
CORRIDOR (BUT PARTICULARLY AROUND LUMBERTON) THERE ARE INCREASING
CHANCES FOR SHOWERS FORECAST...MAINLY FROM MID MORNING THROUGH EARLY
AFTERNOON AS THE UPPER DISTURBANCE CROSSES THE AREA. DESPITE WARMING
TEMPERATURES IN THE AFTERNOON WITH SOME SUNSHINE...NVA AND INCREASED
SUBSIDENT MOTION BEHIND THE SHORTWAVE SHOULD LEAD TO DIMINISHING
RAIN CHANCES.
THE 00Z GFS IS MUCH MORE BULLISH WITH RAIN CHANCES THAN THE 00Z
NAM...AND WITH ITS ADDITIONAL RAINFALL THE GFS HAS MUCH COOLER
TEMPERATURES FORECAST TODAY COMPARED TO THE NAM. GIVEN CURRENT RADAR
RETURNS ALONG I-85 FROM CHARLOTTE THROUGH GREENSBORO THE GFS IS
PROBABLY CORRECT WITH COVERAGE BUT MAY HAVE PLACED ITS QPF MAXIMUM
TOO FAR SOUTH. MY FORECAST IS FOR 20-30 PERCENT COVERAGE OF SHOWERS
ACROSS DARLINGTON-FLORENCE-DILLON-LUMBERTON-ELIZABETHTOWN...WITH
ONLY A 5-10 PERCENT CHANCE AT THE COAST. HIGHS SHOULD RANGE FROM THE
UPPER 80S FROM FLORENCE AND MARION INTO KINGSTREE...WITH MID 80S
ELSEWHERE.
ALTHOUGH AREAS OF MID LEVEL CLOUDINESS WILL HANG AROUND THROUGH
TONIGHT PRECIPITATION CHANCES SHOULD BE TOO LOW FOR MENTION IN THE
FORECAST. TEMPERATURES WILL MODERATE A LITTLE WITH THE CONTINUING
ONSHORE FLOW...WITH LOWS IN THE UPPER 60S FORECAST INLAND AND LOWER
70S AT THE BEACHES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...HIGH PRESSURE WILL SHIFT FARTHER OFF THE
EAST COAST THROUGH THE PERIOD. COASTAL CAROLINAS WILL BASICALLY BE
IN A DEEPER WARMER AND MOISTER RETURN FLOW ON THE WESTERN
PERIPHERY OF THE ATLANTIC RIDGE BY THE END OF THE PERIOD. THE FLOW
WILL SHIFT FROM SE ON WED TO S-SW BY FRI MORNING. ALTHOUGH
DEWPOINT TEMPS WILL BE CREEPING BACK UP TOWARD 70 ON WED...THE
ATMOSPHERIC COLUMN WILL REMAIN RELATIVELY DRY WITH PCP WATER
VALUES AROUND 1.5 INCHES. LOOKS LIKE A MINOR PERTURBATION FROM THE
WEST IN THE MID LEVEL FLOW WILL REACH THE COAST OVERNIGHT WED AND
MAY SEE SOME CLOUDS AND AN ISOLATED SHOWER OR TWO MOVING ACROSS
THE COASTAL WATERS AND POSSIBLY JUST ALONG THE COAST.
OTHERWISE...EXPECT PLENTY OF SUNSHINE FOR WED. BY THURS A DEEPER
SOUTHERLY FLOW WILL CONTINUE TO FEED MOISTURE INTO THE AREA
BRINGING PCP WATER VALUES UP TO 1.75 INCHES...BUT MID TO UPPER
RIDGE WILL NUDGE INTO THE AREA FROM THE EAST. OVERALL EXPECT CU
BUILDUP IN THE AFTERNOON AND ONLY LOCALIZED CONVECTION MAINLY
ALONG THE SEA BREEZE BOUNDARY WITH DRY AIR AND SUBSIDENCE ALOFT TO
PREVENT MORE WIDESPREAD ACTIVITY. TEMPS WILL RUN SLIGHTLY BELOW
NORMAL ON WED WITH MID 80S MOST PLACES AND WILL HEAD BACK TO
NORMAL ON THURS WITH READINGS NEAR 70 FOR LOWS AND CLOSER TO 90
FOR HIGHS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...SOUTHERLY RETURN FLOW WILL PERSIST AROUND
ATLANTIC HIGH PRESSURE AS MID TO UPPER RIDGE BUILDS OVER THE AREA
FROM THE SOUTHEAST FRI INTO SAT. THE SOUTHERN EXTENT OF A COLD
FRONT WILL REACH THE CAROLINAS BY SATURDAY BUT WILL END UP
STALLING WITH PIEDMONT TROUGH INLAND AND SEA BREEZE BOUNDARY BEING
THE MAIN FEATURES TO FOCUS ANY CONVECTION ON BOTH FRI AND
SATURDAY. THE H5 RIDGE UP TO 595 DEM JUST OFF THE COAST FRI INTO
EARLY SAT SHOULD PROVIDE ENOUGH SUBSIDENCE TO KEEP SHOWER ACTIVITY
LIMITED TO MAINLY INLAND AREAS. BY SATURDAY THE RIDGE GETS
SUPPRESSED FARTHER SOUTH AS MID TO UPPER TROUGH BEGINS TO DIG DOWN
THE EAST COAST WITH SFC TROUGH/FRONT SHIFTING SOUTHEAST AND CLOSER
TO THE COAST. BY LATE SUNDAY THROUGH TUESDAY...A MUCH DEEPER
COLUMN OF MOISTURE WILL BE PRESENT WITH PCP WATER VALUES UP ABOVE
2 INCHES. OVERALL EXPECT INCREASING CHC OF MORE WIDESPREAD
CONVECTION INTO EARLY NEXT WEEK WITH GREATER INSTABILITY AND
MOISTURE IN THE ATMOSPHERE AS DECENT UPPER LEVEL SUPPORT.
DEWPOINT TEMPS WILL BE BACK UP IN THE 70S WITH OVERNIGHT LOWS
IN THE MID 70S AND DAY TIME HIGHS REACHING INTO THE 90S. CLOUDS
AND PCP MAY KEEP VALUES SLIGHTLY LOWER EACH AFTERNOON INTO EARLY
NEXT WEEK.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 06Z...EXPECT VFR TO CONTINUE THROUGH THE VALID PERIOD. FEW/SCT
MID TO HIGH CLOUDS WILL CONTINUE TO LINGER ACROSS THE AREA WITH
LIGHT AND VARIABLE WINDS THROUGH THE MORNING HOURS. LATEST COMPUTER
MODELS ARE NOT SUPPORTING FOG DEVELOPMENT...BUT COULD NOT ENTIRELY
RULE OUT ISOLATED AREAS OF GROUND FOG...ESPECIALLY INLAND. AFTER
DAYBREAK...VFR WILL PREVAIL WITH COVERAGE IN MID TO HIGH CLOUDS
INCREASING. LIGHT SOUTH-SOUTHEAST WINDS IN THE MORNING WILL INCREASE
TO 10 KTS THROUGH THE AFTERNOON HOURS. ISOLATED SHOWERS AND TSTMS
COULD DEVELOP ACROSS THE CENTRAL CAROLINAS...POTENTIALLY MOVING AS
FAR EAST AS THE FLO/LBT AIRPORTS IN THE 20-23Z TIMEFRAME BUT
CONFIDENCE IS TOO LOW FOR INCLUSION IN THE FORECAST AT THIS TIME.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE WEDNESDAY THROUGH SATURDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 630 AM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
CANADIAN HIGH PRESSURE CENTERED OFF THE NEW JERSEY COAST IS
EXTENDING A SURFACE RIDGE AXIS SOUTHWESTWARD INTO EASTERN NORTH
CAROLINA AND CENTRAL SOUTH CAROLINA. ALTHOUGH THE MAIN AREA OF HIGH
PRESSURE WILL MOVE FARTHER OFFSHORE TONIGHT THE RIDGE AXIS WILL
REMAIN IN PLACE. THIS SHOULD KEEP OUR WINDS FROM VEERING AROUND TO
THE SOUTH AS NORMALLY OCCURS WITH A DEPARTING EAST COAST HIGH. EAST
TO SOUTHEAST WINDS 10-15 KNOTS THIS MORNING WILL DIMINISH TO AROUND
10 KNOTS FOR THIS AFTERNOON AND TONIGHT. ALTHOUGH THERE WILL BE AN
INCREASE IN CLOUD COVER THIS MORNING...IT APPEARS SHOWER CHANCES
WILL REMAIN CONFINED TO INTERIOR SECTIONS OF THE CAROLINAS. SEAS
CURRENTLY AVERAGE 2-3 FT AT THE BUOYS WITH SHORT WIND-DRIVEN
PERIODS. LITTLE CHANGE IS FORECAST INTO TONIGHT.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...RETURN FLOW AROUND ATLANTIC RIDGE OF HIGH
PRESSURE WILL PERSIST THROUGH THE PERIOD. THE FLOW WILL VEER
AROUND FROM SOUTHEAST ON WED BECOMING MORE S-SW ON THURS. THE
WINDS WILL REMAIN AROUND 10 KTS SPIKING UP A BIT EACH AFTERNOON IN
THE SEA BREEZE. THE PERSISTENT ON SHORE PUSH WILL KEEP SEAS AROUND
2 TO 3 FT WITH SHORTER PERIOD WIND WAVES MIXING WITH A LONGER
PERIOD 9 SECOND SE SWELL.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...EXPECT A SOUTH TO SOUTHWEST FLOW TO
CONTINUE THROUGH THE PERIOD AROUND ATLANTIC HIGH. THE WINDS WILL
VEER SLIGHTLY MORE INTO THE WEEKEND AS PIEDMONT TROUGH BECOMES
MORE PRONOUNCED AND COLD FRONT MOVES INTO THE CAROLINAS FROM THE
NORTHWEST OVER THE WEEKEND. THE GRADIENT WILL TIGHTEN BETWEEN INLAND
TROUGH/FRONT AND HIGH PRESSURE OFF SHORE TO PRODUCE WIND 10 TO 15 KTS
THROUGH THE PERIOD. THE INCREASED SOUTHERLY PUSH WILL PRODUCE A
RISE IN SEAS UP CLOSER TO 3 FT THROUGH THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...TRA/SGL
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
556 AM EDT TUE AUG 6 2013
.SYNOPSIS...
WEAK DISTURBANCE EXITS THE MOUNTAIN COUNTIES THIS MORNING. INSTABILITY
INCREASES LATE TODAY AND OVERNIGHT. STRONGER MID LEVEL DISTURBANCE
PASSES WEDNESDAY. MORE ROUNDS OF CONVECTION INTO THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
ONCE YOU GET SPOILED BY THOSE RARE LOWER DEW POINTS IN THE DOG DAYS
OF SUMMER...YOU HATE TO SEE THEM LEAVE. THE INITIAL MID LEVEL
DISTURBANCE WAS CROSSING THE CENTRAL WV MOUNTAINS THIS EARLY HOUR OF
08Z. A SECONDARY 500 MB VORT IS INDICATED ON THE 07Z RAP MODEL
PASSING N OF BKW AROUND 09-10Z.
MEANWHILE...WHILE THE MID LEVEL MOISTURE INCREASED FROM THE WEST
LAST NIGHT...THE LOWER LEVEL MOISTURE MADE ITS FASTEST INITIAL
CHARGE NORTH...ON THE EASTERN SLOPES OF THE APPALACHIANS. YET...THE
925 TO 850 MB FLOW REMAINS WEAK AND STARTS VEERING MORE TOWARD SOUTH
AND SOUTHWEST. SO TOUGH CLOUD FORECAST TODAY FOR AREAS FROM BKW EAST
INTO THE UPPER GREENBRIER VALLEY.
MEANWHILE...IN THE WAKE OF THE MID LEVEL DISTURBANCE...BREAKS IN THE
CLOUDS COULD YIELD SOME BRIEF FOG IN THE MID OHIO VALLEY FOR DAWN.
NO MAJOR CHANGES TODAY...KEPT A 20/30 POPS OVER THE MOUNTAINS FOR
THE AFTERNOON HEATING IN THE WEAK FLOW. ALSO KEPT THE POSSIBILITY
OF CONVECTION FORMING FOR OUR NE KENTUCKY AND THE TRI STATE AROUND
HTS AFTER 18Z.
MOST MODELS LIKE THE ECMWF...GFS HOLD US DRY OVERNIGHT. BUT NAM
SHOWS MINOR FEATURES WITH INCREASING LOW LEVEL WINDS/FORCING AT
925 MB TO 850 MBS. IT IS TOO PREMATURE TO REMOVE POPS IN OUR
SOUTHERN AND WESTERN COUNTIES FOR TONIGHT. I DID TRY TO HOLD THE
ROUTE 50 CORRIDOR INCLUDING PKB TO CKB DRY MOST OF THE NIGHT. HAVE
POPS INCREASING INTO THE 30 TO 40 PERCENT RANGE ACROSS THE SOUTH
OVERNIGHT. CERTAINLY THE LONGER WE CAN HOLD OFF AREAS OF HEAVIER
CONVECTION THE BETTER...CONSIDERING THE ACTIVE PATTERN INTO THIS
WEEKEND.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
NEW 00Z MODELS LEAVE SOME QUESTION TO HOW THINGS WILL PLAY OUT
THROUGH THE SHORT TERM...AS ECMWF HAS MOVED BEST UPPER LEVEL SUPPORT
FARTHER NORTH WHILE NAM/GFS HAVE BEEN FAIRLY CONSISTENT WITH
PREVIOUS RUNS LOCATION WISE. ALL MODELS HAVE SLOWED DOWN A BIT WITH
THE PRECIP FOR WEDNESDAY...SO TRENDED THAT WAY. DESPITE THE MODEL
DIFFERENCES...THUNDERSTORMS LIKELY WEDNESDAY INTO WEDNESDAY NIGHT
AND WITH PW VALUES CLIMBING ABOVE 2 INCHES HEAVY RAIN IS ALSO
LIKELY. TRAIN OF VORT MAXES CONTINUES AS COLD FRONT APPROACHES
THURSDAY THROUGH FRIDAY. GFS STILL SHOWS THE COLD FRONT TRYING TO
PUSH THROUGH FRIDAY NIGHT...HOWEVER NEW ECMWF STALLS THE SURFACE
FRONT NEAR TO JUST NORTH OF CWA. THINK THE ECMWF MAY BE ON TO
SOMETHING...BUT WITH THIS BEING THE FIRST INDICATION...WON/T JUMP
FULLY ON IT YET. DID INCREASE LOWS FRIDAY NIGHT QUITE A BIT...WITH
ONLY MINIMAL CHANGES MADE TO OTHER TEMPS.
WILL CONTINUE WATER CONCERN MENTION IN HWO. THINK MOST LOCATIONS
SHOULD BE ABLE TO HANDLE WEDNESDAYS BATCH OF HEAVY RAIN SINCE WE
HAVE HAD SOME TIME TO DRY OUT SINCE LAST SIGNIFICANT RAIN...SO AM
MORE CONCERNED WITH REPETITIVE STORMS ADDING UP THROUGH THE END OF
THE WEEK. WITH THAT SAID...CAN NOT RULE OUT LOCALIZED ISSUES
WEDNESDAY DUE TO DOWNPOURS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
USED WPC THINKING FOR THIS PORTION OF THE FORECAST...WITH SOME MINOR
TWEAKS. A COLD FRONT SHOULD BE LOCATED JUST TO OUR SOUTHEAST
SATURDAY. A REINFORCING COLD FRONT SHOULD THEN PUSH SOUTHEAST
SATURDAY/SATURDAY NIGHT...BEFORE WEAK HIGH PRESSURE TAKES CONTROL BY
MONDAY.
BELOW NORMAL TEMPERATURES SHOULD PREVAIL THROUGH THE PERIOD.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
THE MID LEVEL DISTURBANCE CROSSING THE WV MOUNTAINS BETWEEN EKN AND
BKW AT 10Z. WITH BREAKS IN THE CLOUDS IN ITS WAKE...AREAS OF
IFR/LIFR IN FOG FORMING LATE...IN WAKE OF THE RAIN SHOWERS...FROM
EASTERN OHIO ACROSS NORTHERN WEST VIRGINIA INCLUDING PKB TO
CKB...AND EVEN TOWARD W22 AND EKN...FOR A BRIEF TIME AROUND 10Z TO
12Z. MAINLY MVFR IN FOG FURTHER SOUTH TOWARD CRW AND THE SOUTHERN
WV COAL FIELDS.
THE UPSLOPE FLOW ALONG THE EASTERN SLOPES OF THE APPALACHIANS
IS WEAK AND BECOMES MORE SOUTHERLY BY MIDDAY TODAY. THIS LOWERS MY
CONFIDENCE IN THE CEILINGS ALONG THE SPINE OF THE APPALACHIANS ON
EAST INTO THE GREENBRIER VALLEY. BECKLEY IN THE SOUTHERN MOUNTAINS
MAY BE ON THE WESTERN FRINGE OF THIS MAXIMUM IN LOW LEVEL MOISTURE
THIS MORNING...SO HAVE A SCATTERED TO BROKEN DECK THERE AROUND 2
THSD FT AGL.
IN DAYTIME HEATING HAVE SCATTERED TO BROKEN CLOUDS MOSTLY 2 TO 4
THSD FT AGL EXCEPT 4 TO 6 THSD FT ACROSS NORTHERN WV LOWLANDS.
A FEW SHOWERS OR THUNDERSTORMS COULD FORM IN THE AFTERNOON HEATING
OVER THE MOUNTAINOUS COUNTIES. INSTABILITY INCREASES IN THE TRI
STATE VCNTY OF HTS BY 21Z INCLUDING EASTERN KENTUCKY...SO SOME
THUNDERSTORMS COULD DEVELOP THERE LATE TODAY AND LINGER TONIGHT.
WITH MOISTURE INCREASING AT 850 MB AND BELOW WEST OF THE MOUNTAINS
TONIGHT...HAVE MORE WIDESPREAD CEILINGS A 3 TO 4 THSD FT DEVELOPING
00Z TO 06Z WEDNESDAY IN THE WESTERN LOWLANDS. VSBY COULD BE 5 TO 6
MILES IN HAZE WITH INCREASING SURFACE DEW POINTS. INSTABILITY
LINGERS OVERNIGHT...SO HAVE CHANCE POPS FOR CONVECTION CREEPING NE
INTO CENTRAL WV AND CRW VCNTY. EXPECTING DRY CONDITIONS TO HOLD
PKB TO CKB VCNTY OVERNIGHT THRU 12Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: EARLY MORNING FOG IN WAKE OF THE RAIN COULD
LINGER AN HOUR LONGER. COVERAGE AND TIMING OF ANY OVERNIGHT CONVECTION
COULD VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE TUE 08/06/13
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15
CRW CONSISTENCY H M M H M H H H H H H H
HTS CONSISTENCY H M M M M H H H H H H H
BKW CONSISTENCY M M M M M M M M M H H H
EKN CONSISTENCY H M M H H M H H H H H H
PKB CONSISTENCY L L L L H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z WEDNESDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION WEDNESDAY INTO SATURDAY. IN HUMID
AIR IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE CONVECTION...
ESPECIALLY AT NIGHT AND INTO THE MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...JSH
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
728 AM EDT TUE AUG 6 2013
.SYNOPSIS...
AN INCREASINGLY MOIST AND UNSETTLED WEATHER PATTERN WILL PERSIST
INTO THE FIRST PART OF THE WEEKEND...AS MULTIPLE FRONTS APPROACH
AND EVENTUALLY MOVE ACROSS THE REGION. A GRADUAL WARMING TREND TO
NEAR NORMAL TEMPERATURES IS EXPECTED THROUGH THE END OF THE
WEEK...BEFORE ANOTHER SHOT OF SEASONABLY COOL AIR ARRIVES ON
SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
IR SATL TRENDS SINCE MIDNIGHT HAVE DEPICTED A NOTABLE INCREASE IN
LOW-MID LEVEL CLOUDS ACRS A GOOD PORTION OF THE CWA. THE IR SATL
IMAGERY ALSO SHOWS FOG IN THE NRN RIVER/STREAM VALLEYS...WHERE
AIR/WATER TEMP SPREADS ARE AGAIN RUNNING 25-30 DEGREES. VWP/S FROM
IAD/BWI INDICATE THE 925-850MB FLOW HAS VEERED TO THE S-SW...AND
LATEST RUC MESO ANALYSIS SHOW A MSTR AXIS /+13-15C 850MB DEWPTS/
EXTENDING NWD ALONG THE ERN SLOPES OF THE APPLCHNS ON THE WRN
PERIPHERY OF DEPARTING SFC HIGH. THIS ENHANCED MSTR FLUX APPEARS
TO BE OVERRUNNING A WARM FRONT OVER NRN VA WITH DEVELOPING SHOWERS
STARTING TO PEEL NWD FROM THE MAIN W-E RAIN BAND TWD SRN MD.
THEREFORE CANT RULE OUT AN ISOLD SHOWER OVER THE FAR S-CNTRL OR
SERN ZONES PRIOR TO 12Z.
WEAK BUT PERSISTENT LLVL WARM AIR/MSTR ADVECTION AND BROAD ISENT
LIFT OVERRUNNING THE WARM FRONT OVER NRN VA WILL LKLY SUPPORT THE
DEVELOPMENT OF SCT SHOWERS...SPREADING FROM SOUTH TO NORTH DURING
THE MID-LATE MORNING THRU THE AFTN HOURS. SHORTWAVES EMBEDDED
WITHIN THE SEASONABLY STRONG WNW FLOW ALOFT ON THE SRN PERIPHERY
OF CLOSED/SLOW-MOVING UPPER LOW CENTERED OVER NRN MANITOBA/ONTARIO
WILL PROVIDE ENOUGH LARGE SCALE LIFT TO AID IN SHOWER DEVELOPMENT.
A FEW ISOLD THUNDERSTORMS WITH LOCALIZED HEAVY DOWNPOURS MAY ALSO
DEVELOP IN THE AFTN...BUT FOR THE MOST PART INSTABILITY WILL BE
WEAK WITH MEAN CAPES GENERALLY AOB 500 J/KG. MODEL QPFS ARE IN
REASONABLY GOOD AGREEMENT IN KEEPING THE BETTER RAINFALL AXIS TO
THE SOUTH OF THE MASON-DIXON LINE FROM SRN VA NEWD INTO DE...WITH
JUST LGT AMTS /0.1-0.25 INCHES/ OVER CNTRL AND SERN PA. THE
STEADILY INCREASING MSTR AND CLOUDS WILL KEEP MAX TEMPS IN THE
LOW TO MID 70S...AVERAGING A FEW TO SEVERAL DEGREES BELOW NORMAL
DEPENDING ON LOCATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE AFOREMENTIONED WARM FRONT WILL LIFT NWD INTO CNTRL PA TONIGHT
WITH BROAD LLVL SWLY FLOW CONTINUING TO ADVECT HIGHER PWS/60+
DEWPOINTS INTO THE AREA. MDL CONSENSUS STILL FAVORS THE ERN 1/2 TO
1/3 OF THE CWA WITH THE BEST CHC FOR LGT SHOWERS OVERNIGHT INTO
EARLY WEDNESDAY MORNING. IN CONTRAST TO DAYTIME HIGHS...THICKENING
CLOUDS PLUS INCREASING MSTR/DEWPOINTS WILL RESULT IN WARMER THAN
AVG MIN TEMPS WITH READINGS IN THE LOW-MID 60S.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
A ZONAL FLOW ACROSS THE NORTHERN CONUS WILL PREVAIL ACROSS THE
REGION FROM WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. NUMEROUS
EMBEDDED DISTURBANCES WILL ACT ON MONSOONAL MOISTURE FROM THE
SOUTHWESTERN UNITED STATES AND NEARLY STATIONARY BOUNDARY LAYER
FORCING TO PRODUCE A LOCALLY HEAVY RAIN/FLASH FLOOD THREAT ON THU-
FRI BEFORE DRIER AND COOLER CONDS RETURN BY LATE SAT AND SUN.
CLOUDS/PCPN SHOULD OFFSET WARMING ALOFT AND KEEP TEMPS NEAR TO
SLIGHTLY BELOW AVG. MDL DATA INDICATES THE COLD FRONT WILL BECOME
MUCH LESS PROGRESSIVE OR STALL OUT OVER THE UPPER OH VLY WED NGT
INTO THUR.
MODELS AND ENS MEANS CENTER AROUND THE GENERAL IDEA OF A
MODERATELY SLOW PROGRESSION OF THE CLOSED LOW TRACKING EWD BTWN
THE GRT LKS AND HUDSON BAY FROM THU THRU SAT. AT THE SFC...THE
COLD FRONT TURN Q-STNRY BNDRY IN THE OH VLY...WHICH WAS ASSOCIATED
WITH THE LEAD SHORTWAVE TROUGH...SHOULD PUSH SLOWLY EWD ACRS CNTRL
PA ON DAY4/THU. THE SFC PATTERN GETS QUITE COMPLICATED FRI-SAT AS
WPC PROGS SHOW THE FIRST BOUNDARY STALLING OUT OVER THE SRN MID-
ATLC STATES AND SECONDARY COLD FRONT APPROACHING FROM THE GREAT
LAKES. WAVES OF LOW PRESSURE RIDING NEWD ALONG THESE ENCROACHING
FRONTS COULD KEEP UNSETTLED CONDS IN THE FCST THRU THE FIRST PART
OF THE WEEKEND.
ANOTHER PUSH OF WESTERLIES SHOULD OVERSPREAD THE AREA BY SUNDAY
AND NUDGE THE SECOND FRONT EWD TO OR OFF THE COAST. A LARGE AREA OF
CANADIAN HIGH PRESSURE SHOULD SUPPLY ANOTHER REFRESHINGLY COOL/DRY
AIRMASS INTO THE GREAT LAKES AND NORTHEAST BY NEXT SUNDAY. DON`T
EXPECT TEMPS TO FLUCTUATE VERY MUCH THRU THE MEDIUM
RANGE...CONTINUING TO AVG NEAR TO SLIGHTLY BELOW NORMAL FOR EARLY
AUGUST.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
S-SWLY RETURN FLOW ON THE WRN PERIPHERY OF DEPARTING HIGH PRES
SLIDING OFF THE EAST COAST WILL BRING INCREASING MSTR AND
THICKENING LOW-MID CLOUDS INTO CNTRL PA THRU TONIGHT. THE
INCREASINGLY MOIST LLVL FLOW WILL OVERRUN A WARM FRONT LIFTING
SLOWLY NWD FROM VA AND SUPPORT SCT SHOWERS /WITH ISOLD TSRA AND
LOCALLY HVY DOWNPOURS/ INTO THE AFTN. THE S-CNTRL AND SERN
AIRFIELDS STAND THE GREATEST CHC TO BE IMPACTED BY THE SHOWER
ACTIVITY...AND ADDED VCSH TO MDT/LNS BASED ON THE LATEST COSPA
DATA. EXPECT CIG/VIS RESTRICTIONS TO BECOME WIDESPREAD TONIGHT
INTO EARLY WEDNESDAY AS SLY FLOW AND LLVL MSTR CONTINUES TO
INCREASE AHEAD OF THE AFOREMENTIONED WARM FRONT.
OUTLOOK...
WED-FRI...MVFR/VFR. TWO FRONTAL SYSTEMS WILL BRING PERIODS OF
SHOWERS AND OCNL TSTMS.
SAT...BCMG VFR AS HIGH PRES BUILDS SEWD FROM THE UPPER MIDWEST.
&&
.EQUIPMENT...
KCCX HAS SUFFERED MULTIPLE PEDESTAL DYNAMIC FAULTS EARLY THIS
MORNING...CAUSING IT TO GO INTO STAND-BY MODE. THE RADAR WILL
REMAIN IN STAND-BY MODE UNTIL OUR TECHNICIANS CAN DIAGNOSE THE
PROBLEM LATER THIS MORNING. WE APOLOGIZE FOR THE INCONVENIENCE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...DEVOIR/GARTNER
AVIATION...STEINBUGL
EQUIPMENT...STEINBUGL/DEVOIR
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1029 AM CDT TUE AUG 6 2013
.UPDATE...
WEAK SURFACE LOW PRESSURE AREA IN SOUTHEAST ND MOVING EAST LATE
THIS MORNING WITH A WEAK COOL FRONT DROPPING IN BEHIND IT. MOST OF
THE CONVECTION WAS OVER THIS MORNING. THE HRRR MODEL WAS SHOWING
SOME REDEVELOPMENT OVER FAR NE SD/WC MN THIS AFTERNOON AND EVENING
AND ALSO ALONG THE WEAK COOL FRONT DROPPING IN FROM THE NORTH.
THUS...ADJUSTED POPS DOWNWARD ACROSS MOST OF THE REGION THROUGH
THE AFTERNOON.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH THURSDAY
PRECIPITATION CHANCES TODAY WILL BE THE MAIN FORECAST CHALLENGE.
THUNDERSTORMS CURRENTLY ONGOING ALONG AND SOUTH OF I-90 SHOULD
CONTINUE TO DRIFT ESE...CLIPPING ONLY THE SOUTHWEST PORTION OF THE
CWA THROUGH THE MID MORNING HOURS. ADDITIONAL CONVECTION IS MOVING
DUE EAST ALONG I-94 IN NORTH DAKOTA. THESE STORMS SHOULD REMAIN NORTH
OF THIS CWA THROUGH THE MORNING HOURS.
MODELS SORT OF AGREE WITH TWO POSSIBLE CLUSTERS OF STORMS
DEVELOPING LATER THIS AFTERNOON. ONE CLUSTER WOULD BE ACROSS
SOUTHEAST SOUTH DAKOTA WHERE BETTER INSTABILITY IS LOCATED ALONG
WITH A WEAK MID LEVEL SHORT WAVE. IF THIS ACTIVITY DEVELOPS...IT
SHOULD REMAIN SOUTH OF THIS CWA. THE SECONDARY CLUSTER WILL BE
ALONG A SLOWLY SOUTHWARD SINKING COLD FRONT. LESS INSTABILITY
ALONG THE FRONT...BUT SLIGHTLY BETTER 0-6 KM BULK SHEAR MAY RESULT
IN A FEW STRONGER STORMS IN NORTHEAST SOUTH DAKOTA AND WESTERN
MINNESOTA LATER THIS AFTERNOON.
A COOL CANADIAN HIGH PRESSURE SETTLING ACROSS THE REGION WILL
BRING DRY AND TRANQUIL CONDITIONS FOR WEDNESDAY AND FOR MOST OF
WEDNESDAY NIGHT. THEN ANOTHER SURFACE LOW PRESSURE SYSTEM WILL
MOVE ACROSS THE REGION DURING THE EARLY MORNING HOURS ON THURSDAY.
THERE SEEMS TO BE A GENERAL CONSENSUS WITH MOST OF THE CONVECTION
OCCURRING ACROSS SOUTHERN NORTH DAKOTA. THERE IS STILL A CHANCE
FOR THUNDERSTORMS ACROSS MOST OF THE CWA AS A TRAILING COLD FRONT
MOVES SOUTHWARD ACROSS THE CWA ON THURSDAY. SIGNIFICANTLY LESS
INSTABILITY SHOULD RESULT IN GENERAL THUNDERSTORMS.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY NIGHT
NO CHANGES FROM 24 HOURS AGO. NORTHWEST FLOW WILL STEER ONE OR
MORE MID-LEVEL SHORTWAVES THROUGH THE REGION ATOP A DECENT LOW TO
MID-LEVEL BAROCLINIC ZONE...RESULTING IN A COUPLE HALFWAY DECENT
CHANCES FOR MEASURABLE PRECIP OVER A GOODLY AMOUNT OF AREAL
COVERAGE OF THE CWA. SEEMS THE BEST CHANCES FOR PRECIPITATION...RIGHT
NOW...ARE ANCHORED ON FRIDAY NIGHT THROUGH SUNDAY MORNING. 925HPA
AND 850HPA THERMAL PROGS IN THE GFS AND ECMWF SUGGEST TEMPERATURES
WILL REMAIN GENERALLY NEAR TO BELOW NORMAL THROUGH THE PERIOD.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
GOOD VFR AND DRY CONDITIONS ARE EXPECTED AT ALL FOUR TERMINALS
THROUGH THIS AFTERNOON. THEN...A COLD FRONT MOVING THROUGH THE
REGION COULD TOUCH OFF A FEW SHOWERS OR STORMS AT OR NEAR THE
KABR/KATY TERMINALS. THE COLD FRONT WILL ALSO BE SWITCHING WINDS
AROUND TO THE NORTHWEST.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...SD
LONG TERM...DORN
AVIATION...DORN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
620 AM CDT TUE AUG 6 2013
.UPDATE...
ISSUED AT 620 AM CDT TUE AUG 6 2013
FOG HAS THICKEN UP OVER SOUTHWEST WI...AND PER OBS AND CALLS TO
DISPATCH...1/4 MILE VSBYS WERE FAIRLY COMMON. EXPANDED THE DENSE FOG
ADV AS A RESULT. BUFKIT SOUNDINGS CONTINUE TO SUGGEST THAT WINDS
WILL START TO MIX OUT THE FOG BY 9-10 AM.
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CDT TUE AUG 6 2013
AT 3 AM...DENSE FOG WAS REPORTED ACROSS MUCH OF SOUTHEAST
MINNESOTA...NORTHEAST IOWA...IN THE WISCONSIN RIVER VALLEY...
AND ON THE RIDGE TOPS SURROUNDING THE MISSISSIPPI RIVER. THE
VISIBILITIES AT OUR OFFICE IS LESS THAN A QUARTER MILE. AS A TROUGH
MOVES THROUGH NORTHEAST IOWA AND WESTERN WISCONSIN EARLY THIS
MORNING...THE WINDS WILL INCREASE ALOFT AND SOME DRIER AIR WILL
HELP DISSIPATE THE FOG BETWEEN 06.10Z AND 06.14Z.
FOR THIS AFTERNOON AND TONIGHT...WE WILL HAVE TO WATCH 2 AREAS OF
CONVECTION WHICH IS LOCATED CURRENTLY OVER THE DAKOTAS. THE LATEST
RAP SHOWS THAT 850 MB MOISTURE TRANSPORT INTO THESE AREAS WILL
KEEP THIS CONVECTION GOING THROUGH THE MORNING. THESE AREAS ARE
CAUSING HAVOC ON THE MESO MODELS. BOTH THE 06.00Z NMM AND ARW ARE
SHOWING THAT THE CONVECTION OVER NORTH DAKOTA IS THE MOST DOMINANT
AND THEY BRING A ROBUST AREA OF SHOWERS AND THUNDERSTORMS INTO
SOUTHEAST MINNESOTA AND NORTHEAST IOWA. MEANWHILE THE HRRR SHOW
THAT THE CONVECTION ACROSS NORTH DAKOTA WILL MOVE EAST SOUTHEAST
ACROSS NORTHERN MINNESOTA. MEANWHILE THE CONVECTION ACROSS WESTERN
SOUTH DAKOTA WILL DEVELOP A MESOSCALE VORTICITY WILL DEVELOP OUT
OF THIS THUNDERSTORM COMPLEX. LOOKING AT THE LATEST WATER VAPOR
AND RADAR IMAGERY THIS ACTUALLY MAKES A LOT OF SENSE. AS THIS
VORTICITY ENCOUNTERS INCREASING CAPES ACROSS EASTERN SOUTH
DAKOTA...NORTHWEST IOWA...AND SOUTHWEST MINNESOTA...THERE WILL BE
THE REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS LATE THIS MORNING
AND AFTERNOON. ADDITIONAL LINES OF THUNDERSTORMS WILL LIKELY
DEVELOP AHEAD OF AN APPROACHING COLD FRONT ACROSS WEST CENTRAL
AND NORTHWEST MINNESOTA. THERE IS MORE THAN ADEQUATE SHEAR FOR THESE
THUNDERSTORMS TO BECOME ORGANIZED. THIS WILL INCLUDE SPLITTING
SUPERCELLS AND BOWING LINE SEGMENTS. THE MAIN SEVERE WEATHER
THREAT ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND WEST
CENTRAL AND SOUTHWEST WISCONSIN WILL BE LIKELY LARGE HAIL...DAMAGING
WINDS...AND POSSIBLY ISOLATED TORNADOES FROM 6 PM THROUGH MIDNIGHT.
AS THE COLD FRONT SWEEPS THROUGH THE AREA OVERNIGHT...THE THREAT
FOR SHOWERS AND THUNDERSTORMS WILL QUICKLY COME TO AN END ACROSS
THE AREA FROM NORTHWEST TO SOUTHEAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM CDT TUE AUG 6 2013
ON THURSDAY NIGHT AND FRIDAY...THE 06.00Z MODELS ARE IN GOOD
AGREEMENT THAT A VIGOROUS SHORT WAVE TROUGH WILL MOVE EAST ACROSS
NORTHERN MINNESOTA AND UPPER MICHIGAN. AS THIS OCCURS...A COLD
FRONT WILL MOVE SOUTH THROUGH THE NORTHERN HALVES OF MINNESOTA AND
WISCONSIN. THERE LOOKS TO BE ENOUGH INSTABILITY AND SYNOPTIC
FORCING FOR THE DEVELOPMENT OF SCATTERED SHOWERS AND
THUNDERSTORMS ALONG AND AHEAD OF THIS FRONT. WITH THE BEST 0-6 KM
SHEAR IN THE WAKE OF THIS SYSTEM...NOT EXPECTING TO SEE ANY SEVERE
WEATHER FROM THIS SYSTEM.
FROM LATE SATURDAY NIGHT INTO MONDAY...THE MODELS CONTINUE TO
STRUGGLE WITH THE LOCATION AND TIMING OF SHORT WAVES MOVING
OUT OF THE NORTHERN PLAINS. AS A RESULT CONFIDENCE IN THE TIMING
AND LOCATION OF PRECIPITATION DURING THIS TIME PERIOD IS LOWER
THAN NORMAL. AS A RESULT...JUST WENT WITH THE ALL BLEND FOR THIS
TIME PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 620 AM CDT MON AUG 5 2013
SFC TROUGH HELPED CLEAR DENSE FOG FROM KRST EARLY THIS MORNING...BUT
MORE FG THEN FORMED A FEW MILES BEHIND THE TROUGH - WHERE THE SKIES
WERE CLEAR. THIS COULD STILL IMPACT KRST FOR A COUPLE HOURS EARLY
THIS MORNING...MOSTLY IFR/MVFR. KLSE WILL ALSO DEAL WITH SOME BR
FOR A FEW HOURS.
COLD FRONT WILL SWEEP IN FROM THE WEST TONIGHT...WITH A BAND OF
SHRA/TS ALONG AND AHEAD OF IT. THERE WILL BE SOME LOWER VSBYS WITH
THE STORMS...AND SOME CLOUD BASE LOWERING. WILL KEEP VFR VCTS/TSRA
FOR THE MOMENT...ALLOWING FOR LATER UPDATES WHEN TIMING CAN BE
BETTER REFINED. COULD BE SOME ENHANCED GUSTINESS AROUND THE STORMS
TOO.
THE FRONT LOOKS TO TRACK ACROSS KRST/KLSE IN THE 06-09Z TIME FRAME.
MODEL RH FIELDS SUGGESTING THAT LOW STRATUS COULD FOLLOW/DEVELOP IN
THE WAKE OF THE FRONT...ESPECIALLY THE NAM. FORECAST CONFIDENCE
SHAKY ON JUST HOW LOW CIGS COULD GO...BUT WILL TREND THEM
DOWNWARD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR WIZ053>055-
061.
MN...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ094-095.
DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ096.
IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ008>010-
018-019-029.
DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ011-030.
&&
$$
UPDATE.......RIECK
SHORT TERM...BOYNE
LONG TERM....BOYNE
AVIATION.....RIECK
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
250 PM MST TUE AUG 6 2013
.UPDATE...
UPDATED AVIATION DISCUSSION...
&&
.SYNOPSIS...
SKIES WILL GRADUALLY CLEAR TONIGHT AS DRIER AIR MOVES INTO THE
REGION FROM THE SOUTHWEST. DRY WEATHER WILL PREVAIL FOR MUCH OF THE
UPCOMING WEEK WITH PRECIP CHANCES CONFINED MAINLY TO EASTERN
ARIZONA. TEMPERATURES WILL REMAIN BELOW NORMAL WEDNESDAY...BUT COULD
APPROACH THE 110 DEGREE MARK BY EARLY NEXT WEEK.
&&
.DISCUSSION...
REGIONAL RADAR MOSAIC INDICATES SHOWERS ARE TAPERING OFF ACROSS THE
PHOENIX METRO...WHILE NEW SHOWERS AND THUNDERSTORMS ARE DEVELOPING
ACROSS EASTERN/SOUTHERN ARIZONA. A BAND OF THUNDERSTORMS WERE ALSO
LOCATED ACROSS YAVAPAI COUNTY AND WERE MOVING SOUTHWARD /IN THE
DEFORMATION AREA OF THE UPPER LEVEL SHORTWAVE/. MEANWHILE TO THE
WEST...JUST YOUR AVERAGE AUGUST DAY WITH TEMPS AROUND 100 WITH SUNNY
SKIES AND NO PRECIP TO SPEAK OF.
17Z HRRR MODEL SEEMS TO HAVE CAUGHT ON TO THE PRESENT SITUATION AND
ADVERTISES CONVECTION TO MOVE INTO SOUTHERN GILA COUNTY LATER THIS
AFTERNOON...MEANWHILE THE YAVAPAI STORMS WILL TRY AND DRIFT
SOUTHWARD INTO THE FAR NORTHEAST CORNER OF THE PHX METRO. SPC MESO
PAGE INDICATES A FEW HUNDRED J/KG OF MLCAPE RESIDES IN THIS AREA
WHICH HAS BEEN LARGELY FREE OF RAIN TODAY...SEEMS PLAUSIBLE A FEW
STORMS COULD SURVIVE IN THAT ENVIRONMENT. THIS IS IN LINE WITH
PREVIOUS UPDATES TO THE FORECAST...AND I WILL HANG ONTO 10-20 POPS
ACROSS THE PHOENIX AREA THROUGH THE EVENING...WITH HIGHER POPS IN
THE MOUNTAINS TO THE EAST. THE TROUGH WILL MOVE OUT OF THE AREA
TONIGHT AND SUBSIDENCE BEHIND THE LOW SHOULD DRY THINGS OUT BEFORE
MIDNIGHT.
THE FORECAST FOR WEDNESDAY THROUGH NEXT WEEK IS LARGELY UNCHANGED AS
THE UPPER FLOW BECOMES MORE SOUTHWESTERLY AND MOISTURE GETS
DISPLACED INTO NEW MEXICO. COULD SEE SOME ISOLATED MOUNTAIN
SHOWERS/THUNDERSTORMS WEDNESDAY/THURSDAY GIVEN LINGERING PWATS
AROUND 1.1-1.3 INCHES...BUT CHANCES SHOULD REMAIN BELOW CLIMO GIVEN
UNFAVORABLE FLOW ALOFT ALL THE WAY THROUGH EARLY NEXT WEEK.
A GRADUAL INCREASE IN TEMPERATURES WILL TAKE PLACE THROUGH THE
UPCOMING WEEKEND...BUT WITH THE UPPER LOW TO THE NORTHWEST...500MB
HEIGHTS WILL REMAIN BELOW 590DM AND AFTERNOON HIGHS WILL STAY WITHIN
A COUPLE DEGREES OF NORMAL THROUGH SATURDAY. MODELS ARE IN GOOD
AGREEMENT LIFTING THE UPPER LOW NORTHEASTWARD LATE THIS WEEKEND
ALLOWING FOR HEIGHTS TO INCREASE ACROSS THE DESERT SOUTHWEST AND
SHIFTING THE SUBTROPICAL HIGH CLOSER TO THE FOUR CORNERS REGION.
WARMING TEMPERATURES SUNDAY AND MONDAY ARE EXPECTED WITH SOME LOWER
DESERT HIGHS AROUND 110 DEGREES. AN INCREASE IN BOUNDARY LAYER
MOISTURE IS EXPECTED ACROSS FAR EASTERN ARIZONA EARLY NEXT WEEK
ALLOWING FOR SLIGHTLY BETTER CHANCES FOR MONSOON STORMS MAINLY
ACROSS THE HIGHER TERRAIN EAST OF PHOENIX.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
SHOWERS AND CLOUDINESS WILL CONTINUE TO DECLINE OVER THE PHOENIX
AREA THIS AFTERNOON. HOWEVER...STORMS OVER PINAL COUNTY AND FAR
NORTHEAST MARICOPA COUNTY ARE STILL POSSIBLE THROUGH 03Z AND COULD
BRUSH NORTH AND EAST PORTIONS OF THE METRO BUT PROBABILITY TOO LOW
TO REFLECT IN THE TAFS. SURFACE WINDS WILL FAVOR EASTERLY DIRECTIONS
THROUGH WEDNESDAY MORNING EXCEPT FOR A SHORT PERIOD LATE THIS
AFTERNOON AND EVENING. ANTICIPATE CLEARING SKIES OVERNIGHT.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
CLEAR SKIES CAN BE EXPECTED THROUGH WEDNESDAY. WINDS WILL FAVOR
SOUTHERLY DIRECTIONS OVER THE LOWER COLORADO RIVER VALLEY...WITH
GUSTS OF 20-25 KTS IN THE AFTERNOONS. WINDS WILL BE LIGHTER OVER THE
IMPERIAL VALLEY AND FAVOR EASTERLY DIRECTIONS IN THE
AFTERNOONS...WESTERLY AT NIGHT.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
AN AREA OF LOW PRESSURE WILL REMAIN SITUATED ALONG THE CALIFORNIA
COAST THURSDAY THROUGH THE WEEKEND KEEPING A RATHER DRY SOUTHWEST
FLOW ALOFT IN PLACE ACROSS THE AREA. THE ONLY THREAT FOR SHOWERS OR
THUNDERSTORMS WILL BE OVER THE HIGHER TERRAIN AREAS EAST OF PHOENIX
STARTING ON SATURDAY AND CONTINUING INTO MONDAY. A SLIGHT WARMING
TREND IS EXPECTED WITH HIGH TEMPERATURES CLIMBING FROM NEAR OR
SLIGHTLY BELOW NORMAL VALUES THURSDAY TO A FEW DEGREES ABOVE CLIMO
BY THE WEEKEND. MINIMUM HUMIDITIES WILL RANGE FROM THE LOW TEENS TO
SINGLE DIGITS OVER THE LOWER DESERTS THROUGH THE PERIOD...WITH FAIR
RECOVERIES AT NIGHT. NO SIGNIFICANT WIND IS ANTICIPATED...JUST LOCAL
AFTERNOON AND EARLY EVENING GUSTINESS FAVORING UPSLOPE OR THE
SOUTHWEST.
$$
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/KUHLMAN
AVIATION...AJ
FIRE WEATHER...CB
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
108 PM MST TUE AUG 6 2013
.SYNOPSIS...
SKIES WILL GRADUALLY CLEAR TONIGHT AS DRIER AIR MOVES INTO THE
REGION FROM THE SOUTHWEST. DRY WEATHER WILL PREVAIL FOR MUCH OF THE
UPCOMING WEEK WITH PRECIP CHANCES CONFINED MAINLY TO EASTERN
ARIZONA. TEMPERATURES WILL REMAIN BELOW NORMAL WEDNESDAY...BUT COULD
APPROACH THE 110 DEGREE MARK BY EARLY NEXT WEEK.
&&
.DISCUSSION...
REGIONAL RADAR MOSAIC INDICATES SHOWERS ARE TAPERING OFF ACROSS THE
PHOENIX METRO...WHILE NEW SHOWERS AND THUNDERSTORMS ARE DEVELOPING
ACROSS EASTERN/SOUTHERN ARIZONA. A BAND OF THUNDERSTORMS WERE ALSO
LOCATED ACROSS YAVAPAI COUNTY AND WERE MOVING SOUTHWARD /IN THE
DEFORMATION AREA OF THE UPPER LEVEL SHORTWAVE/. MEANWHILE TO THE
WEST...JUST YOUR AVERAGE AUGUST DAY WITH TEMPS AROUND 100 WITH SUNNY
SKIES AND NO PRECIP TO SPEAK OF.
17Z HRRR MODEL SEEMS TO HAVE CAUGHT ON TO THE PRESENT SITUATION AND
ADVERTISES CONVECTION TO MOVE INTO SOUTHERN GILA COUNTY LATER THIS
AFTERNOON...MEANWHILE THE YAVAPAI STORMS WILL TRY AND DRIFT
SOUTHWARD INTO THE FAR NORTHEAST CORNER OF THE PHX METRO. SPC MESO
PAGE INDICATES A FEW HUNDRED J/KG OF MLCAPE RESIDES IN THIS AREA
WHICH HAS BEEN LARGELY FREE OF RAIN TODAY...SEEMS PLAUSIBLE A FEW
STORMS COULD SURVIVE IN THAT ENVIRONMENT. THIS IS IN LINE WITH
PREVIOUS UPDATES TO THE FORECAST...AND I WILL HANG ONTO 10-20 POPS
ACROSS THE PHOENIX AREA THROUGH THE EVENING...WITH HIGHER POPS IN
THE MOUNTAINS TO THE EAST. THE TROUGH WILL MOVE OUT OF THE AREA
TONIGHT AND SUBSIDENCE BEHIND THE LOW SHOULD DRY THINGS OUT BEFORE
MIDNIGHT.
THE FORECAST FOR WEDNESDAY THROUGH NEXT WEEK IS LARGELY UNCHANGED AS
THE UPPER FLOW BECOMES MORE SOUTHWESTERLY AND MOISTURE GETS
DISPLACED INTO NEW MEXICO. COULD SEE SOME ISOLATED MOUNTAIN
SHOWERS/THUNDERSTORMS WEDNESDAY/THURSDAY GIVEN LINGERING PWATS
AROUND 1.1-1.3 INCHES...BUT CHANCES SHOULD REMAIN BELOW CLIMO GIVEN
UNFAVORABLE FLOW ALOFT ALL THE WAY THROUGH EARLY NEXT WEEK.
A GRADUAL INCREASE IN TEMPERATURES WILL TAKE PLACE THROUGH THE
UPCOMING WEEKEND...BUT WITH THE UPPER LOW TO THE NORTHWEST...500MB
HEIGHTS WILL REMAIN BELOW 590DM AND AFTERNOON HIGHS WILL STAY WITHIN
A COUPLE DEGREES OF NORMAL THROUGH SATURDAY. MODELS ARE IN GOOD
AGREEMENT LIFTING THE UPPER LOW NORTHEASTWARD LATE THIS WEEKEND
ALLOWING FOR HEIGHTS TO INCREASE ACROSS THE DESERT SOUTHWEST AND
SHIFTING THE SUBTROPICAL HIGH CLOSER TO THE FOUR CORNERS REGION.
WARMING TEMPERATURES SUNDAY AND MONDAY ARE EXPECTED WITH SOME LOWER
DESERT HIGHS AROUND 110 DEGREES. AN INCREASE IN BOUNDARY LAYER
MOISTURE IS EXPECTED ACROSS FAR EASTERN ARIZONA EARLY NEXT WEEK
ALLOWING FOR SLIGHTLY BETTER CHANCES FOR MONSOON STORMS MAINLY
ACROSS THE HIGHER TERRAIN EAST OF PHOENIX.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
SCT TO NUMEROUS LIGHT -SHRA WILL AFFECT CNTRL ARIZONA TERMINALS
THROUGH AT LEAST 18Z...WITH SOME LESSER CHANCE OF RAIN LINGERING
INTO THE EARLY AFTERNOON. CIGS SHOULD REMAIN AOA 8K FT WITH VFR
VSBYS...THOUGH ISOLD AREAS COULD VERY BRIEFLY DIP INTO MVFR
CATEGORIES IN MORE MDT SHRA. COVERAGE AND PROBABILITIES OF LOWER
FLIGHT CATEGORIES ARE FAR TOO REMOTE TO EVEN MENTION IN THIS TAF
PACKAGE. PRIMARY IMPACTS WILL BE PERIODIC WET CONDITIONS FOR GROUNDS
CREWS AND PARTIAL MTN OBSCURATION ON DEPARTURE/APPROACH.
SFC WINDS WILL GENERALLY REMAIN ELY THROUGH THE MORNING BEFORE
GRADUALLY VEERING TO SWLY DURING THE AFTERNOON. THERE MAY BE
OCCASIONAL PERIODS OF MORE VARIABLE WINDS WITHIN SHRA THIS MORNING.
OTHERWISE...CIGS SHOULD SLOWLY LIFT AND CLEAR BY WEDNESDAY MORNING.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
FAIRLY EXTENSIVE HIGH CLOUDS WILL AFFECT TERMINALS THROUGH TUESDAY
EVENING...WITH SHOWERS REMAINING WELL TO THE EAST INTO CNTRL
ARIZONA. WINDS WILL GENERALLY REMAIN FROM A SLY/SELY DIRECTION
THROUGH THE EVENING WITH OCCASIONAL HIGHER GUSTS AT KBLH. WITH
MODERATE CONFIDENCE...HAVE SFC WINDS SHIFTING TO WLY AT KIPL AFTER
SUNSET.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
AN AREA OF LOW PRESSURE WILL REMAIN SITUATED ALONG THE CALIFORNIA
COAST THURSDAY THROUGH THE WEEKEND KEEPING A RATHER DRY SOUTHWEST
FLOW ALOFT IN PLACE ACROSS THE AREA. THE ONLY THREAT FOR SHOWERS OR
THUNDERSTORMS WILL BE OVER THE HIGHER TERRAIN AREAS EAST OF PHOENIX
STARTING ON SATURDAY AND CONTINUING INTO MONDAY. A SLIGHT WARMING
TREND IS EXPECTED WITH HIGH TEMPERATURES CLIMBING FROM NEAR OR
SLIGHTLY BELOW NORMAL VALUES THURSDAY TO A FEW DEGREES ABOVE CLIMO
BY THE WEEKEND. MINIMUM HUMIDITIES WILL RANGE FROM THE LOW TEENS TO
SINGLE DIGITS OVER THE LOWER DESERTS THROUGH THE PERIOD...WITH FAIR
RECOVERIES AT NIGHT. NO SIGNIFICANT WIND IS ANTICIPATED...JUST LOCAL
AFTERNOON AND EARLY EVENING GUSTINESS FAVORING UPSLOPE OR THE
SOUTHWEST.
$$
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/KUHLMAN
AVIATION...MO
FIRE WEATHER...CB
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
916 AM MST TUE AUG 6 2013
.SYNOPSIS...
A TEMPORARY INCREASE IN MONSOON MOISTURE ASSOCIATED WITH AN UPPER
LEVEL LOW WILL BRING PERIODS OF LIGHT RAIN TODAY AND THE POSSIBILITY
OF AN ISOLATED THUNDERSTORM. THE EXTENSIVE CLOUD COVER AND LIGHT
RAIN WILL LEAD TO A MUCH COOLER DAY TODAY WITH HIGHS WELL BELOW
NORMAL. A DRYING TREND WILL START ON WEDNESDAY AND WILL CONTINUE
INTO THE WEEKEND...KEEPING PRECIPITATION CHANCES CONFINED MAINLY TO
EASTERN ARIZONA.
&&
.DISCUSSION...
STILL LOOKING AT QUITE A BIT OF SHOWERS ACROSS THE REGION AS OF
16Z...AS A SHORTWAVE TROUGH SLOWLY MOVES THROUGH SONORA AND ARIZONA.
RAINFALL TOTALS HAVE BEEN ON THE LOW SIDE SO FAR...GENERALLY A FEW
HUNDREDTHS TO 0.15 INCHES VALLEY-WIDE. NOT SURPRISINGLY...THIS HAS
ALSO PUT A SERIOUS DENT IN OUR TEMPERATURES. READINGS AS OF 16Z ARE
ONLY IN THE LOW/MID 70S ACROSS THE METRO...EVEN SKY HARBOR IS STILL
SITTING IN THE UPPER 70S. MEANWHILE TO THE WEST...DRY CONDITIONS
REMAIN IN PLACE AND TEMPS HAVE BEEN WARMING ON SCHEDULE.
THE SHORTWAVE TROUGH WILL MOVE THROUGH CENTRAL ARIZONA LATER THIS
MORNING AND A GRADUAL DRYING TREND SHOULD COMMENCE AFTER NOON. RADAR
MOSAIC ALREADY STARTING TO INDICATE THE WESTERN EDGE OF THE PRECIP
IS BREAKING DOWN OVER WESTERN MARICOPA COUNTY...AND THIS TREND
SHOULD CONTINUE THROUGH THE AFTERNOON HOURS. THAT BEING SAID...A
SECONDARY TROUGH SOUTH OF PIMA COUNTY WILL MOVE INTO ARIZONA LATER
TODAY. HI-RES WRF MODELS AND THE HRRR INDICATE CONVECTION SHOULD
DEVELOP OVER THE MOUNTAINS EAST OF PHOENIX AFTER 21Z...AND I
INCREASED POPS IN THESE AREAS BY ABOUT 10-20 PERCENT. RAP/HRRR MODEL
ALSO INDICATING SCATTERED SHOWERS REMAINING IN PLACE ACROSS THE
METRO THROUGH MID AFTERNOON. I INCREASED POPS ACROSS THE METRO A BIT
AS WELL THROUGH 00Z ALTHOUGH THEY SHOULD BE SCATTERED IN NATURE. THE
THREAT FOR SEVERE WEATHER EAST OF PHOENIX APPEARS SLIM GIVEN MOSTLY
MOIST ADIABATIC PROFILES...BUT THUNDER CERTAINLY SEEMS PLAUSIBLE IN
AREAS THAT HAVE REMAINED DRY THIS MORNING.
TEMPERATURES ARE A HUGE CHALLENGE TODAY. IF CLOUDS HANG AROUND MUCH
PAST 1-2PM...WE DONT STAND A CHANCE OF GETTING OUT OF THE UPPER
80S. WITH A LITTLE CLEARING...LOWER 90S SEEMS A MORE LIKELY
SOLUTION. I LOWERED HIGHS A BIT AND AM NOW GOING WITH HIGHS AROUND
87-92 IN THE METRO. EITHER WAY...NOWHERE NEAR NORMAL FOR EARLY
AUGUST. FORECAST A LITTLE MORE CLEAR-CUT FROM YUMA WESTWARD...HIGHS
IN THE LOWER 100S SEEMS LIKE A SAFE BET GIVEN SUNNY SKIES.
&&
.PREVIOUS DISCUSSION...
THE SOUTHERN VORT CENTER WILL QUICKLY EXIT THE AREA BY EARLY
EVENING...MOVING INTO NORTHERN ARIZONA BY MIDNIGHT TONIGHT. BEHIND
THIS...MUCH DRIER WESTERLY FLOW WILL SLIDE INTO THE AREA ENDING ANY
RAIN CHANCES AND BRINGING CLEARING SKIES TONIGHT. BOUNDARY LAYER
MOISTURE WILL TAKE A BIT LONGER TO BE SCOURED OUT AND ONCE DAYTIME
MIXING KICKS ON WEDNESDAY...SURFACE DEW POINTS WILL BE BACK IN THE
40/50S AND MORE LIKE 30/40S FOR THURSDAY THROUGH SATURDAY.
AFTER WEDNESDAY...THE MUCH DRIER UPPER LEVEL PATTERN WILL DOMINATE
ACROSS THE DESERT SOUTHWEST. A NEARLY STATIONARY CLOSED UPPER LOW
SITUATED OFF THE CALIFORNIA COAST WILL FINALLY COME ASHORE SOMETIME
WEDNESDAY LOWERING HEIGHTS ACROSS OUR REGION. PWATS FALL TO BELOW AN
INCH BY THURSDAY AND 1000-700MB MIXING RATIOS FALL TO AROUND 5 G/KG.
A GRADUAL INCREASE IN TEMPERATURES WILL TAKE PLACE THROUGH THE
UPCOMING WEEKEND...BUT WITH THE UPPER LOW TO THE NORTHWEST...500MB
HEIGHTS WILL REMAIN BELOW 590DM AND AFTERNOON HIGHS WILL STAY WITHIN
A COUPLE DEGREES OF NORMAL THROUGH SATURDAY. MODELS ARE IN GOOD
AGREEMENT LIFTING THE UPPER LOW NORTHEASTWARD LATE THIS WEEKEND
ALLOWING FOR HEIGHTS TO INCREASE ACROSS THE DESERT SOUTHWEST AND
SHIFTING THE SUBTROPICAL HIGH CLOSER TO THE FOUR CORNERS REGION.
WARMING TEMPERATURES SUNDAY AND MONDAY ARE EXPECTED WITH SOME LOWER
DESERT HIGHS AROUND 110 DEGREES. AN INCREASE IN BOUNDARY LAYER
MOISTURE IS EXPECTED ACROSS FAR EASTERN ARIZONA EARLY NEXT WEEK
ALLOWING FOR SLIGHTLY BETTER CHANCES FOR MONSOON STORMS MAINLY
ACROSS THE HIGHER TERRAIN EAST OF PHOENIX.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
SCT TO NUMEROUS LIGHT -SHRA WILL AFFECT CNTRL ARIZONA TERMINALS
THROUGH AT LEAST 18Z...WITH SOME LESSER CHANCE OF RAIN LINGERING
INTO THE EARLY AFTERNOON. CIGS SHOULD REMAIN AOA 8K FT WITH VFR
VSBYS...THOUGH ISOLD AREAS COULD VERY BRIEFLY DIP INTO MVFR
CATEGORIES IN MORE MDT SHRA. COVERAGE AND PROBABILITIES OF LOWER
FLIGHT CATEGORIES ARE FAR TOO REMOTE TO EVEN MENTION IN THIS TAF
PACKAGE. PRIMARY IMPACTS WILL BE PERIODIC WET CONDITIONS FOR GROUNDS
CREWS AND PARTIAL MTN OBSCURATION ON DEPARTURE/APPROACH.
SFC WINDS WILL GENERALLY REMAIN ELY THROUGH THE MORNING BEFORE
GRADUALLY VEERING TO SWLY DURING THE AFTERNOON. THERE MAY BE
OCCASIONAL PERIODS OF MORE VARIABLE WINDS WITHIN SHRA THIS MORNING.
OTHERWISE...CIGS SHOULD SLOWLY LIFT AND CLEAR BY WEDNESDAY MORNING.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
FAIRLY EXTENSIVE HIGH CLOUDS WILL AFFECT TERMINALS THROUGH TUESDAY
EVENING...WITH SHOWERS REMAINING WELL TO THE EAST INTO CNTRL
ARIZONA. WINDS WILL GENERALLY REMAIN FROM A SLY/SELY DIRECTION
THROUGH THE EVENING WITH OCCASIONAL HIGHER GUSTS AT KBLH. WITH
MODERATE CONFIDENCE...HAVE SFC WINDS SHIFTING TO WLY AT KIPL AFTER
SUNSET.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
AN AREA OF LOW PRESSURE WILL REMAIN SITUATED ALONG THE CALIFORNIA
COAST THURSDAY THROUGH THE WEEKEND KEEPING A RATHER DRY SOUTHWEST
FLOW ALOFT IN PLACE ACROSS THE AREA. THE ONLY THREAT FOR SHOWERS OR
THUNDERSTORMS WILL BE OVER THE HIGHER TERRAIN AREAS EAST OF PHOENIX
STARTING ON SATURDAY AND CONTINUING INTO MONDAY. A SLIGHT WARMING
TREND IS EXPECTED WITH HIGH TEMPERATURES CLIMBING FROM NEAR OR
SLIGHTLY BELOW NORMAL VALUES THURSDAY TO A FEW DEGREES ABOVE CLIMO
BY THE WEEKEND. MINIMUM HUMIDITIES WILL RANGE FROM THE LOW TEENS TO
SINGLE DIGITS OVER THE LOWER DESERTS THROUGH THE PERIOD...WITH FAIR
RECOVERIES AT NIGHT. NO SIGNIFICANT WIND IS ANTICIPATED...JUST LOCAL
AFTERNOON AND EARLY EVENING GUSTINESS FAVORING UPSLOPE OR THE
SOUTHWEST.
$$
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/KUHLMAN
AVIATION...MO
FIRE WEATHER...CB
AREA FORECAST DISCUSSION
NWS MIAMI FL
253 PM EDT TUE AUG 6 2013
.SHORT TERM (TONIGHT-THURSDAY NIGHT)...
A MID/UPPER LEVEL RIDGE CURRENTLY STRETCHES ACROSS THE SOUTHERN
STATES INTO THE ATLANTIC WITH AN INVERTED TROUGH MOVING WEST ACROSS
THE EASTERN BAHAMAS BENEATH THE RIDGE AXIS. AT THE SURFACE, A WEAK
SURFACE TROUGH EXTENDS FROM SOUTH FLORIDA INTO THE NORTHERN BAHAMAS
AND INTO THE CENTRAL ATLANTIC. THE SURFACE TROUGH IS A VERY SHALLOW
FEATURE AND THIS COMBINED WITH THE UPPER TROUGH TO THE EAST AND
RIDGE TO THE NORTH IS RESULTING IN VERY WEAK SURFACE PRESSURE
GRADIENT BECOMING NORTH TO NORTHEAST FLOW ABOVE 5K FT. THE 12Z MFL
SOUNDING CAPTURED THIS WELL AND ALSO SHOWS PWAT REMAINING AT AROUND
TWO INCHES. ALL OF THIS SPELLS CONVECTIVE DEVELOPMENT MOVING OFF TO
THE SOUTH AND THE HRRR HAS BEEN INDICATING THIS ALSO WITH GOOD
INITIAL TIMING AND LOCATION. THE SOUNDING ALSO SHOWED MID LEVEL
LAPSE RATES QUITE WEAK AT 5.8 DEGREES CELSIUS/KM AND A 500 MB
TEMPERATURE OF ONLY -5.9 WHICH IS NEARLY TWO DEGREES WARMER THAN
AVERAGE FOR EARLY AUGUST SO ONLY ISOLATED STRONG STORMS ARE EXPECTED
THIS AFTERNOON AT BEST.
THE MID LEVEL TROUGH WILL CONTINUE MOVING TO THE WEST IN THE SHORT
TERM WITH ALL GLOBAL MODELS IN VERY GOOD AGREEMENT SHIFTING IT INTO
THE CENTRAL BAHAMAS ON WEDNESDAY AND THE WESTERN BAHAMAS BY LATE
THURSDAY. AS THE TROUGH APPROACHES SOUTH FLORIDA, THE EASTERLY FLOW
WILL DEEPEN AS THE UPPER RIDGE TO THE NORTH MOVES LITTLE THROUGH
THIS PERIOD. THE ATMOSPHERIC MOISTURE PROFILE WILL CHANGE LITTLE
THROUGH WEDNESDAY AND WITH THE EAST FLOW DEEPENING, THE PRIMARY
THREAT FOR CONVECTIVE ACTIVITY WILL TEND TO BE MORNING SHOWERS ALONG
THE EAST COAST AND THEN SCATTERED SHOWERS/THUNDERSTORMS DEVELOPING
OVER THE INTERIOR DURING THE AFTERNOON AND MOVING TOWARDS THE
SOUTHWEST COAST. THE STEERING WINDS ARE ONLY EXPECTED TO BE AROUND 5
MPH SO THE THREAT WILL EXIST FOR POSSIBLE LOCALLY HEAVY RAINS IN THE
NAPLES AREA.
THERE COULD ACTUALLY BE LESS ACTIVITY ON THURSDAY AS THE TROUGH
APPROACHES WHICH PLACES SOUTH FLORIDA ON THE SUBSIDENCE SIDE. THIS
TROUGH CURRENTLY SHOWS UP VERY WELL IN WATER VAPOR IMAGERY WITH
STRONG SUBSIDENCE SHOWING UP TO ITS WEST. THE MODELS ALSO SHOW THE
LOW MAINTAINING ITS CURRENT STRENGTH SO ANOTHER REASON THERE COULD
BE LESS ACTIVITY. BY THURSDAY NIGHT, THE ATMOSPHERE WILL UNDERGO
GOOD DESTABILIZATION AS THE TROUGH MOVES INTO THE STRAITS OF
FLORIDA. THE GFS IS INDICATING 500 MB TEMPERATURES COOLING TO -11
SOUTHEAST OF KEY LARGO AND -10 OFF THE SOUTHEAST COAST. THE NAM IS A
TAD BID SLOWER WITH THE MOVEMENT BUT STILL SHOWS THIS SAME COLD POOL
ABOUT 50-100 MILES TO THE SOUTHEAST OF THE GFS POSITION. AT ANY
RATE, THIS COULD SET OFF SOME IMPRESSIVE LIGHTNING DISPLAYS TO OUR
SOUTHEAST THURSDAY EVENING AND NIGHT AS CONVECTIVE CELLS COULD
EASILY DEVELOP OVER THE ATLANTIC WATERS WITH SUCH COLD TEMPERATURES
ALOFT MOVING ACROSS THE GULF STREAM WATERS MAKING THE ENVIRONMENT
VERY UNSTABLE. BUT AS ALWAYS AS WE GET OUT WITH TIME, CONFIDENCE IS
LESS SO IT IS A WAIT AND SEE APPROACH.
.LONG TERM (FRIDAY-TUESDAY)...
LATE IN THE WEEK AND INTO THE WEEKEND AND EARLY NEXT WEEK, THE
TROUGH WILL CONTINUE WESTWARD INTO THE GULF OF MEXICO ALLOWING THE
ATLANTIC RIDGE TO ALSO BUILD WEST. THIS WILL STABILIZE THE
ATMOSPHERE ONCE AGAIN AND THE GFS IS ALSO SHOWING SIGNIFICANT DRYING
TAKING PLACE WITH PWAT DROPPING WELL UNDER TWO INCHES. SO WHILE
FRIDAY COULD REMAIN QUITE ACTIVE, MUCH LESS ACTIVITY IS LIKELY AS WE
GET INTO THE WEEKEND AND CROSS OVER INTO NEXT WEEK.
&&
.AVIATION...
ISOLATED HEAVY SHOWERS AND STORMS HAVE ALREADY DEVELOPED THIS
AFTERNOON ACROSS PORTIONS OF THE AREA...MOSTLY SOUTH OF A LINE FROM
FLL TO APF WITH THE MEAN LOW-LEVEL NORTHERLY FLOW IN PLACE. ALTHOUGH
MOST OF THE AFTERNOON/EVENING ACTIVITY SHOULD REMAIN JUST INLAND OF
THE TAF SITES...WE WILL CONTINUE TO INCLUDE VCTS AT MOST SITES FROM
21Z THROUGH THE EVENING HOURS AND UPDATE AS CONDITIONS EVOLVE.
OVERNIGHT TONIGHT THROUGH WEDNESDAY...THE FLOW SHOULD BECOME MORE
EASTERLY...WHICH WILL TRANSLATE TO THE BEST RAINFALL CHANCES SETTING
UP ACROSS THE INTERIOR AND WESTERN LOCATIONS OF SOUTH FLORIDA
THROUGH THE DAY WEDNESDAY.
&&
.MARINE...
LIGHT AND VARIABLE WIND TONIGHT WILL SLOWLY BECOME EAST BY
WEDNESDAY AND THEN STRENGTHENING LATER IN THE WEEK AS THE GRADIENT
TIGHTENS. THIS WILL BUILD SEAS OVER THE NEXT COUPLE OF DAYS BUT
REMAIN WELL BELOW ADVISORY CRITERIA.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 76 89 78 89 / 20 20 20 20
FORT LAUDERDALE 78 90 81 90 / 20 20 20 20
MIAMI 78 91 79 89 / 20 20 20 20
NAPLES 77 92 76 93 / 20 40 30 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
236 PM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURFACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTION ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCED
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVECTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPAGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE SCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
WHILE THE CONVECTION IS LIKELY TO BE ON A WEAKENING TREND INTO
WEDNESDAY MORNING...IF NOT ALREADY OVERNIGHT...GUIDANCE HAS AGREED
ON A SLOWER MOVEMENT OF THE FRONT IN THE PAST 24 HOURS. SO HAVE
INCREASED POPS IN EASTERN AREAS DURING EARLY WEDNESDAY.
CONFIDENCE...MEDIUM.
WEDNESDAY AFTERNOON THROUGH FRIDAY...AS THE FRONT EASES IN SPEED
THERE IS CONCERN FOR CONVECTION IN THE SOUTHEAST PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON. HIGH MOISTURE WILL STILL OWE TO
MODEST TO HIGH INSTABILITY ALONG THE BOUNDARY. EVEN A SLOWER
FRONTAL MOVEMENT MAY MEAN WE COULD HAVE A SEVERE WEATHER THREAT IN
THE FAR SOUTHERN FORECAST AREA. FOR THE TIME BEING MAINTAIN THE
CHANCE POPS IN THE SOUTHERN AREA.
LARGER INCREASES IN POPS WERE MADE FOR THU NIGHT AND INTO FRI
ACROSS THE SOUTHEAST HALF OF THE FORECAST AS ONE AND POSSIBLY
MULTIPLE WAVES TRAVERSE THE BOUNDARY...SPREADING SOUTHERLY 850MB
FLOW NORTH OF THE FEATURE POTENTIALLY LEADING TO SOME SHOWERS AND
STORMS ACROSS OUR AREA...DESPITE NORTHERLY SURFACE FLOW. THE MAIN
FOCUS FOR ANYTHING OF HIGH IMPACT STILL LOOKS TO BE WELL SOUTH OF
THE AREA. FOR TEMPERATURES ON WED-FRI HAVE GONE JUST A COUPLE
DEGREES ABOVE AN OFFICIAL/MODEL BLEND.
THIS WEEKEND...LITTLE CHANGES MADE TO THE GOING FORECAST AS HIGH
PRESSURE IS STILL FAVORED IN THAT TIME YIELDING LIKELY PLEASANT
WEATHER. GUIDANCE MAY BE A LITTLE QUICK ON BRINGING PRECIP
CHANCES BACK SUNDAY NIGHT...BUT FOR THE TIME BEING HAVE GONE WITH
A BLEND DUE TO ATTENTION ON THE SHORT TERM.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* IMPROVING CIG TRENDS EARLY THIS AFTERNOON.
* CHANCE OF TSRA TONIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
THE RESIDUAL LOW CLOUD REMNANTS FOLLOWING EARLIER PCPN ARE QUICKLY
DISSIPATING AND ALL SITES SHOULD GO VFR BTWN 18-19Z. THE REMAINDER
OF THE AFTERNOON AND INTO THE EVENING HOURS SHOULD BE QUIET WITH
VFR CIGS/VIS AND GENERALLY WESTERLY WINDS UNDER 10KT.
THE NEXT CONCERN WILL BE THE CHANCES FOR THUNDERSTORMS TO AFFECT
THE TERMINALS DURG THE EARLY MORNING HOURS. LATEST GUIDANCE STILL
SUGGESTS THE POSSIBILITY OF A THUNDERSTORM COMPLEX TO DEVELOP
TONIGHT FROM WISCONSIN TO IOWA IN ADVANCE OF AN APPROACHING COLD
FRONT. EXPECT THAT THE BEST WINDOW OF OPPORTUNITY FOR TSRA TO
IMPACT THE TERMINALS WILL BE GENERALLY BETWEEN 06Z-12Z. BASED ON
THE LATEST LOCAL HIGH RES MODELS...HAVE PUSHED BACK THE TIMING A
LITTLE FROM THE GOING FORECAST AND INTRODUCED A PROB30 GROUP
OUTLINING THE MOST LIKELY TIMING BASED ON THE LATEST
GUIDANCE...WHICH WOULD BRING TSRA TO THE RFD AREA BTWN 06-10Z AND
THE CHICAGO AREA BTWN 08-12Z. THE TS POTENTIAL SHOULD QUICKLY SHUT
OFF FOLLOWING THE FROPA...SO THE DURATION OF TS WILL BE HIGHLY
DEPENDENT ON THE FRONTAL PROGRESSION SPEED. SO...WILL GO WITH THE
PROB30 GROUP FOR NOW AND REFINE THE FORECAST TIMING...POSSIBLY
UPGRADING TO A TEMPO OR PREVAILING GROUP AS ANTICIPATED CONDITIONS
WARRANT.
THE ONLY OTHER SIGNIFICANT CONCERN WILL BE WIND DIRECTION TRENDS.
CURRENTLY...ANTICIPATE THAT WINDS SHOULD REMAIN GENERALLY WLY
THROUGH THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING. AS
THE FRONT APPROACHES...EXPECT THAT WINDS SHOULD BACK TO MORE SLY
BEFORE QUICKLY VEERING NWLY FOLLOWING THE FROPA. WITH THE
EXPECTATION OF THE ENVIRONMENT AROUND ANY THUNDERSTORMS...WINDS
SHOULD GENERALLY REMAIN AT OR BELOW 10KT GIVING A RELATIVELY
PRESSURE GRADIENT OVER THE REGION AND THE LACK OF A STRONG COLD
AIR PUSH FOLLOWING THE FROPA.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TONIGHT...WITH
LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY
SOUTH OF CHICAGO THURSDAY NIGHT.
MONDAY...SLIGHT CHANCE OF TSRA.
KJB
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1251 PM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURFACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTION ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCED
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVECTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPAGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE SCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
WHILE THE CONVECTION IS LIKELY TO BE ON A WEAKENING TREND INTO
WEDNESDAY MORNING...IF NOT ALREADY OVERNIGHT...GUIDANCE HAS AGREED
ON A SLOWER MOVEMENT OF THE FRONT IN THE PAST 24 HOURS. SO HAVE
INCREASED POPS IN EASTERN AREAS DURING EARLY WEDNESDAY.
CONFIDENCE...MEDIUM.
WEDNESDAY AFTERNOON THROUGH FRIDAY...AS THE FRONT EASES IN SPEED
THERE IS CONCERN FOR CONVECTION IN THE SOUTHEAST PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON. HIGH MOISTURE WILL STILL OWE TO
MODEST TO HIGH INSTABILITY ALONG THE BOUNDARY. EVEN A SLOWER
FRONTAL MOVEMENT MAY MEAN WE COULD HAVE A SEVERE WEATHER THREAT IN
THE FAR SOUTHERN FORECAST AREA. FOR THE TIME BEING MAINTAIN THE
CHANCE POPS IN THE SOUTHERN AREA.
LARGER INCREASES IN POPS WERE MADE FOR THU NIGHT AND INTO FRI
ACROSS THE SOUTHEAST HALF OF THE FORECAST AS ONE AND POSSIBLY
MULTIPLE WAVES TRAVERSE THE BOUNDARY...SPREADING SOUTHERLY 850MB
FLOW NORTH OF THE FEATURE POTENTIALLY LEADING TO SOME SHOWERS AND
STORMS ACROSS OUR AREA...DESPITE NORTHERLY SURFACE FLOW. THE MAIN
FOCUS FOR ANYTHING OF HIGH IMPACT STILL LOOKS TO BE WELL SOUTH OF
THE AREA. FOR TEMPERATURES ON WED-FRI HAVE GONE JUST A COUPLE
DEGREES ABOVE AN OFFICIAL/MODEL BLEND.
THIS WEEKEND...LITTLE CHANGES MADE TO THE GOING FORECAST AS HIGH
PRESSURE IS STILL FAVORED IN THAT TIME YIELDING LIKELY PLEASANT
WEATHER. GUIDANCE MAY BE A LITTLE QUICK ON BRINGING PRECIP
CHANCES BACK SUNDAY NIGHT...BUT FOR THE TIME BEING HAVE GONE WITH
A BLEND DUE TO ATTENTION ON THE SHORT TERM.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* IMPROVING CIG TRENDS EARLY THIS AFTERNOON.
* CHANCE OF TSRA TONIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
THE RESIDUAL LOW CLOUD REMNANTS FOLLOWING EARLIER PCPN ARE QUICKLY
DISSIPATING AND ALL SITES SHOULD GO VFR BTWN 18-19Z. THE REMAINDER
OF THE AFTERNOON AND INTO THE EVENING HOURS SHOULD BE QUIET WITH
VFR CIGS/VIS AND GENERALLY WESTERLY WINDS UNDER 10KT.
THE NEXT CONCERN WILL BE THE CHANCES FOR THUNDERSTORMS TO AFFECT
THE TERMINALS DURG THE EARLY MORNING HOURS. LATEST GUIDANCE STILL
SUGGESTS THE POSSIBILITY OF A THUNDERSTORM COMPLEX TO DEVELOP
TONIGHT FROM WISCONSIN TO IOWA IN ADVANCE OF AN APPROACHING COLD
FRONT. EXPECT THAT THE BEST WINDOW OF OPPORTUNITY FOR TSRA TO
IMPACT THE TERMINALS WILL BE GENERALLY BETWEEN 06Z-12Z. BASED ON
THE LATEST LOCAL HIGH RES MODELS...HAVE PUSHED BACK THE TIMING A
LITTLE FROM THE GOING FORECAST AND INTRODUCED A PROB30 GROUP
OUTLINING THE MOST LIKELY TIMING BASED ON THE LATEST
GUIDANCE...WHICH WOULD BRING TSRA TO THE RFD AREA BTWN 06-10Z AND
THE CHICAGO AREA BTWN 08-12Z. THE TS POTENTIAL SHOULD QUICKLY SHUT
OFF FOLLOWING THE FROPA...SO THE DURATION OF TS WILL BE HIGHLY
DEPENDENT ON THE FRONTAL PROGRESSION SPEED. SO...WILL GO WITH THE
PROB30 GROUP FOR NOW AND REFINE THE FORECAST TIMING...POSSIBLY
UPGRADING TO A TEMPO OR PREVAILING GROUP AS ANTICIPATED CONDITIONS
WARRANT.
THE ONLY OTHER SIGNIFICANT CONCERN WILL BE WIND DIRECTION TRENDS.
CURRENTLY...ANTICIPATE THAT WINDS SHOULD REMAIN GENERALLY WLY
THROUGH THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING. AS
THE FRONT APPROACHES...EXPECT THAT WINDS SHOULD BACK TO MORE SLY
BEFORE QUICKLY VEERING NWLY FOLLOWING THE FROPA. WITH THE
EXPECTATION OF THE ENVIRONMENT AROUND ANY THUNDERSTORMS...WINDS
SHOULD GENERALLY REMAIN AT OR BELOW 10KT GIVING A RELATIVELY
PRESSURE GRADIENT OVER THE REGION AND THE LACK OF A STRONG COLD
AIR PUSH FOLLOWING THE FROPA.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TONIGHT...WITH
LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY
SOUTH OF CHICAGO THURSDAY NIGHT.
MONDAY...SLIGHT CHANCE OF TSRA.
KJB
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1103 AM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURFACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTION ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCED
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVECTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPAGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE SCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
WHILE THE CONVECTION IS LIKELY TO BE ON A WEAKENING TREND INTO
WEDNESDAY MORNING...IF NOT ALREADY OVERNIGHT...GUIDANCE HAS AGREED
ON A SLOWER MOVEMENT OF THE FRONT IN THE PAST 24 HOURS. SO HAVE
INCREASED POPS IN EASTERN AREAS DURING EARLY WEDNESDAY.
CONFIDENCE...MEDIUM.
WEDNESDAY AFTERNOON THROUGH FRIDAY...AS THE FRONT EASES IN SPEED
THERE IS CONCERN FOR CONVECTION IN THE SOUTHEAST PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON. HIGH MOISTURE WILL STILL OWE TO
MODEST TO HIGH INSTABILITY ALONG THE BOUNDARY. EVEN A SLOWER
FRONTAL MOVEMENT MAY MEAN WE COULD HAVE A SEVERE WEATHER THREAT IN
THE FAR SOUTHERN FORECAST AREA. FOR THE TIME BEING MAINTAIN THE
CHANCE POPS IN THE SOUTHERN AREA.
LARGER INCREASES IN POPS WERE MADE FOR THU NIGHT AND INTO FRI
ACROSS THE SOUTHEAST HALF OF THE FORECAST AS ONE AND POSSIBLY
MULTIPLE WAVES TRAVERSE THE BOUNDARY...SPREADING SOUTHERLY 850MB
FLOW NORTH OF THE FEATURE POTENTIALLY LEADING TO SOME SHOWERS AND
STORMS ACROSS OUR AREA...DESPITE NORTHERLY SURFACE FLOW. THE MAIN
FOCUS FOR ANYTHING OF HIGH IMPACT STILL LOOKS TO BE WELL SOUTH OF
THE AREA. FOR TEMPERATURES ON WED-FRI HAVE GONE JUST A COUPLE
DEGREES ABOVE AN OFFICIAL/MODEL BLEND.
THIS WEEKEND...LITTLE CHANGES MADE TO THE GOING FORECAST AS HIGH
PRESSURE IS STILL FAVORED IN THAT TIME YIELDING LIKELY PLEASANT
WEATHER. GUIDANCE MAY BE A LITTLE QUICK ON BRINGING PRECIP
CHANCES BACK SUNDAY NIGHT...BUT FOR THE TIME BEING HAVE GONE WITH
A BLEND DUE TO ATTENTION ON THE SHORT TERM.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* CIG TRENDS WITH LOW MVFR CIGS LEVEL THIS MORNING.
* TIMING THE IMPROVEMENT OF CIGS DURING THE LATE MORNING HOURS.
IMPROVEMENT MIGHT BE A LITTLE LATER THAN TAF INDICATES...BUT
WHEN IMPROVEMENT COMES...SHOULD BE QUICK.
* CHANCE OF TSRA TONIGHT.
KREIN
//DISCUSSION...UPDATED 12Z...
THERE ARE A FEW LINGERING SHOWERS LEFT OVER FROM THE OVERNIGHT
STORMS ACROSS NORTH CENTRAL ILLINOIS. HOWEVER...THE PRIMARY FORECAST
CONCERNS IN THE NEAR TERM WILL BE CIGS AND VIS TRENDS THIS
MORNING. ATTENTION THEN TURNS TO LATER TONIGHT INTO WEDNESDAY
MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A MESSY
MORNING ACROSS THE AREA. CIGS AND VIS ARE TANKING IN THE WAKE OF
THE HIGHER CLOUD COVER AND AREA OF SHOWERS. MOST AREAS WEST OF THE
CHICAGO AREA ARE UNDER 800 FEET WITH VIS NOW DOWN TO 1/2 SM AT
KRFD. I EXPECT THESE DETERIORATING CONDITIONS TO CONTINUE TO
OVERSPREAD THE EASTERN TAF SITES EARLY THIS MORNING. I SUSPECT
THAT THE VIS WILL DROP AT KORD AND KMDW AS WELL FOR A PERIOD EARLY
THIS MORNING...BUT CONFIDENCE ON HOW LOW THEY WILL DROP IS
LOW...BUT MVFR VIS AROUND 5 SM IS CERTAINLY POSSIBLE GIVEN THE
TRENDS TO THE WEST. SO BY FAR THE BIGGEST DEAL WILL BE THE LOW CIGS.
CIGS WILL PROB BE A BIT SLOW TO RECOVER THIS MORNING...WITH NO BIG
IMPROVEMENTS UNTIL AFTER 14-15 UTC THIS MORNING. HOWEVER...ONCE
THINGS IMPROVE LATER THIS MORNING...AVIATION WEATHER CONCERNS
SHOULD BE AT A MINIMUM THROUGH THE REST OF THE DAY.
IT APPEARS LIKELY THAT A COMPLEX OF THUNDERSTORMS WILL DEVELOP
WEST OF THE AREA ACROSS IOWA AND SOUTHWESTERN WISCONSIN DURING THE
EVENING TODAY. THIS ACTIVITY APPEARS THAT IT WILL MOVE OVER
NORTHERN ILLINOIS LATER TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY
AT THE EASTERN TAF SITS. IT MAY BE IN A WEAKENING STATE AS IT
ARRIVES ACROSS NORTHEASTERN ILLINOIS...BUT I DID CONTINUE THE
MENTION OF SHRA AND VCTS ALL THE TAFS AFTER 06 UTC TONIGHT. IT IS
POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW HOURS PRIOR
TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE TONIGHT
INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE APPROACHES
THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN THE AIR MASS
AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* LOW CONFIDENCE IN TIMING OF IMPROVEMENT OF THE MVFR CIGS THIS
MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TONIGHT...WITH
LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY
SOUTH OF CHICAGO THURSDAY NIGHT.
MONDAY...SLIGHT CHANCE OF TSRA.
KJB
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
224 PM EDT TUE AUG 6 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 243 AM EDT TUE AUG 6 2013
WARMER AIR IS SET TO ARRIVE IN INDIANA TODAY AS HIGH PRESSURE OVER
THE EAST COAST PROVIDES A WARMER AND MORE HUMID SOUTHERLY FLOW
ALONG WITH DRY WEATHER. A MORE ACTIVE WEATHER PATTERN WILL TAKE
SHAPE THROUGH THE MIDDLE OF THE WEEK AS A COLD FRONT IS EXPECTED
TO PUSH TOWARD INDIANA LATE TONIGHT AND STALL ACROSS SOUTHERN
INDIANA THROUGH THURSDAY THE FRONT WILL BRING CHANCES FOR SHOWERS
AND STORMS FROM LATE TONIGHT THROUGH FRIDAY.
HIGH PRESSURE IS EXPECTED TO ARRIVE LATE FRIDAY AND BRING A RETURN
TO DRY WEATHER FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 944 AM EDT TUE AUG 6 2013
BUMPED UP CLOUD COVER THIS MORNING DUE TO SATELLITE TRENDS AS LOW
DECK HAS BEEN OVERSPREADING THE AREA. LOOKS LIKE IT WILL TAKE A
BIT LONGER TO SCATTER OUT AND THUS TRENDED MOSTLY CLOUDY TO LAST
THROUGH MID AFTERNOON FOR MOST OF THE AREA. WITH THIS INCREASE IN
CLOUD COVER HAVE ALSO LOWER HIGH TEMPERATURES FOR THE DAY...ONLY
BY A DEGREE OR SO IN THE NORTH AND CENTRAL BUT BY A FEW DEGREES IN
THE SOUTHWEST SINCE DEBRIS CLOUDS WILL LIKELY KEEP THAT AREA
MOSTLY CLOUDY THROUGH MUCH OF THE DAY. RAP SHOWS SOME ISOLATED TO
SCATTERED CONVECTIVE DEVELOPMENT LATER THIS AFTERNOON BUT OTHER
MODELS STILL LOOK DRY. WITH SOME SUBSIDENCE AND DRY AIR ALOFT AND
THE RAP ALSO SHOWING SOME THINGS NOW THAT ARE NOT OCCURRING WILL
CONTINUE WITH DRY FORECAST THROUGH THE DAY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 243 AM EDT TUE AUG 6 2013
MAIN FOCUS DURING THIS PERIOD WILL BE POPS.
MODELS ARE IN PRETTY GOOD AGREEMENT OF THE OVERALL TREND OF A
WET...ACTIVE PATTERN.
GFS AND NAM BOTH SUGGEST THE FIRST SHORT WAVE ARRIVING IN THE AREA
LATE TONIGHT AMID THE NW FLOW ALOFT. FORECAST SOUNDINGS HINT AT A
SLOW TOP DOWN STYLE SATURATION BY 12Z. THUS WILL KEEP THE EVENING
DRY...BUT TREND TOWARD HIGHER CHANCES FOR RAIN DURING THE
OVERNIGHT HOURS. 310K GFS ISENTROPIC SURFACE ALSO SHOWS A GOOD
SURGE OF ISENTROPIC LIFT WITH SPECIFIC HUMIDITIES RISING TO NEAR
8 G/KG. WILL TREND LOWS AT OR ABOVE MAVMOS VALUES DUE TO EXPECTED
WARM AIR ADVECTION...CLOUDS...AND PRECIP.
ON WEDNESDAY MORNING...THE GFS AND NAM SUGGEST A COLD FRONT
TROUGH LINGERING ACROSS THE STATE AS THE UPPER SUPPORT FROM THE
OVERNIGHT PERIOD DEPARTS. FORECAST SOUNDINGS SUGGEST DRYING
OUT...HOWEVER PLENTY OF CAPE...IN EXCESS OF 2000 J/KG REMAINS
AVAILABLE. PWATS ARE ALSO NEAR 1.75 INCHES...VERY MOIST. CONVECTIVE
TEMPS ON WEDNESDAY AFTERNOON ARE VERY ATTAINABLE...IN THE LOWER
80S...AND THE GFS 310K ISENTROPIC SURFACE SHOWS STRONG LIFT WITH
AGAIN A VERY MOIST AIR MASS WITH SPECIFIC HUMIDITIES OVER 9 G/KG.
MEANWHILE AT THE SURFACE A WARM FRONT STALLS ACROSS SOUTHERN
INDIANA...FURTHER ACTING AS A FOCUS FOR LOWER LEVEL CONVERGENCE.
THUS ANY HEATING ON WEDNESDAY SHOULD LEAD TO DEVELOPMENT. WILL
TREND POPS AT OR ABOVE MAVMOS...PARTICULARLY DURING THE AFTERNOON.
GIVEN THE EXPECTED CLOUDS AND RAIN...WILL TREND HIGHS AT OR BELOW
MAVMOS.
GFS DEPICTS A SHORT WAVE RIDING ACROSS THE WARM FRONT ACROSS THE
SOUTHERN PARTS OF THE FORECAST AREA ON WEDNESDAY NIGHT...AGAIN A
VERY WARM AND MOIST AIR MASS WILL REMAIN IN PLACE. FORECAST
SOUNDINGS ACROSS THE AREA ALSO INDICATE DEEP SATURATION BY
THURSDAY...AND NOW WITH PWATS IN EXCESS OF 2 INCHES. FAVORABLE
CAPE IS ALSO AVAILABLE. ALOFT IT APPEARS AS IF THE TROPICAL PLUME
THAT IS CURRENTLY FLOWING ACROSS THE PLAINS INTO THE DEEP SOUTH WILL
SHIFT EAST BY WEDNESDAY AND THURSDAY...ALLOWING THIS DEEPER
MOISTURE TO SURGE INTO INDIANA AND THE OHIO VALLEY...PARTICULARLY
ACROSS THE SOUTHERN PARTS OF OUR STATE. THUS WILL CONTINUE TO
RAISE POPS THROUGH THURSDAY NIGHT...TRENDING HIGHS COOLER THAN
MAVMOS AND LOWS WARMER...GIVEN THE EXPECTED CLOUDS AND RAIN.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 224 PM EDT TUE AUG 6 2013
EXTENDED MODELS IN FAIR AGREEMENT ON A COLD FRONT DROPPING TO NEAR
THE OHIO RIVER 12Z SATURDAY WITH NORTHWEST FLOW LOFT. THE FRONT
SHOULD SETTLE GRADUALLY FURTHER SOUTH THROUGH THE WEEKEND WITH HIGH
PRESSURE BUILDING IN BEHIND THE FRONT. THIS SCENARIO SUGGESTS
THUNDERSTORM CHANCES FRIDAY NIGHT...WITH MOSTLY SMALL POPS AND
MAINLY ACROSS THE SOUTH...THEREAFTER. HAD TO TINKER ABOUT WITH
REGIONAL ALLBLEND TO REFLECT THAT. THIS FAMILIAR RECENT PATTERN ALSO
STRONGLY SUGGESTS BELOW NORMAL TEMPERATURES ONCE AGAIN. REGIONAL
INITIALIZATION HAD A GOOD HANDLE ON THAT.
&&
.AVIATION /DISCUSSION FOR 141800Z TAF ISSUANCE/...
ISSUED AT 100 PM EDT SUN JUL 14 2013
MVFR CEILINGS LOOK LIKE THEY PERSIST ALL DAY PER MODEL
SOUNDINGS...CONVECTIVE CONDENSATION LEVELS AND CU DEVELOPMENT PROGS.
HOWEVER...WOULD NOT RULE OUT CEILINGS TO 3500 FEET AFTER 20Z IF ANY
BREAKS OCCUR IN THE OVERCAST. OTHERWISE...SHOULD BE DRY UNTIL AFTER
00Z. THEN...ILL-DEFINED WARM FRONT IS EXPECTED TO MOVE THROUGH AFTER
04Z. WOULD NOT RULE OUT STORMS ALONG AND AHEAD OF THE WARM
FRONT...HOWEVER WITH CONVERGENCE WEAK...AND LITTLE GOING ON NOW
AHEAD OF THE FRONT...WILL LEAVE OUT MENTION OF THUNDER OVERNIGHT AND
JUST GO WITH VCTS AFTER 20Z WEDNESDAY AT IND ASSOCIATED WITH A COLD
FRONT APPROACHING FROM THE NORTHWEST.
SOUTH AND SOUTHWEST WINDS WILL BE 10 KNOTS OR LESS THROUGH THE
PERIOD. FINALLY...WILL THROW IN MVFR FOG AFTER 09Z AS DEW POINTS
INCREASE TO AROUND 70 BEHIND THE WARM FRONT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...CP
SHORT TERM...PUMA
LONG TERM....MK
AVIATION...MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
100 PM EDT TUE AUG 6 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 243 AM EDT TUE AUG 6 2013
WARMER AIR IS SET TO ARRIVE IN INDIANA TODAY AS HIGH PRESSURE OVER
THE EAST COAST PROVIDES A WARMER AND MORE HUMID SOUTHERLY FLOW
ALONG WITH DRY WEATHER. A MORE ACTIVE WEATHER PATTERN WILL TAKE
SHAPE THROUGH THE MIDDLE OF THE WEEK AS A COLD FRONT IS EXPECTED
TO PUSH TOWARD INDIANA LATE TONIGHT AND STALL ACROSS SOUTHERN
INDIANA THROUGH THURSDAY THE FRONT WILL BRING CHANCES FOR SHOWERS
AND STORMS FROM LATE TONIGHT THROUGH FRIDAY.
HIGH PRESSURE IS EXPECTED TO ARRIVE LATE FRIDAY AND BRING A RETURN
TO DRY WEATHER FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 944 AM EDT TUE AUG 6 2013
BUMPED UP CLOUD COVER THIS MORNING DUE TO SATELLITE TRENDS AS LOW
DECK HAS BEEN OVERSPREADING THE AREA. LOOKS LIKE IT WILL TAKE A
BIT LONGER TO SCATTER OUT AND THUS TRENDED MOSTLY CLOUDY TO LAST
THROUGH MID AFTERNOON FOR MOST OF THE AREA. WITH THIS INCREASE IN
CLOUD COVER HAVE ALSO LOWER HIGH TEMPERATURES FOR THE DAY...ONLY
BY A DEGREE OR SO IN THE NORTH AND CENTRAL BUT BY A FEW DEGREES IN
THE SOUTHWEST SINCE DEBRIS CLOUDS WILL LIKELY KEEP THAT AREA
MOSTLY CLOUDY THROUGH MUCH OF THE DAY. RAP SHOWS SOME ISOLATED TO
SCATTERED CONVECTIVE DEVELOPMENT LATER THIS AFTERNOON BUT OTHER
MODELS STILL LOOK DRY. WITH SOME SUBSIDENCE AND DRY AIR ALOFT AND
THE RAP ALSO SHOWING SOME THINGS NOW THAT ARE NOT OCCURRING WILL
CONTINUE WITH DRY FORECAST THROUGH THE DAY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 243 AM EDT TUE AUG 6 2013
MAIN FOCUS DURING THIS PERIOD WILL BE POPS.
MODELS ARE IN PRETTY GOOD AGREEMENT OF THE OVERALL TREND OF A
WET...ACTIVE PATTERN.
GFS AND NAM BOTH SUGGEST THE FIRST SHORT WAVE ARRIVING IN THE AREA
LATE TONIGHT AMID THE NW FLOW ALOFT. FORECAST SOUNDINGS HINT AT A
SLOW TOP DOWN STYLE SATURATION BY 12Z. THUS WILL KEEP THE EVENING
DRY...BUT TREND TOWARD HIGHER CHANCES FOR RAIN DURING THE
OVERNIGHT HOURS. 310K GFS ISENTROPIC SURFACE ALSO SHOWS A GOOD
SURGE OF ISENTROPIC LIFT WITH SPECIFIC HUMIDITIES RISING TO NEAR
8 G/KG. WILL TREND LOWS AT OR ABOVE MAVMOS VALUES DUE TO EXPECTED
WARM AIR ADVECTION...CLOUDS...AND PRECIP.
ON WEDNESDAY MORNING...THE GFS AND NAM SUGGEST A COLD FRONT
TROUGH LINGERING ACROSS THE STATE AS THE UPPER SUPPORT FROM THE
OVERNIGHT PERIOD DEPARTS. FORECAST SOUNDINGS SUGGEST DRYING
OUT...HOWEVER PLENTY OF CAPE...IN EXCESS OF 2000 J/KG REMAINS
AVAILABLE. PWATS ARE ALSO NEAR 1.75 INCHES...VERY MOIST. CONVECTIVE
TEMPS ON WEDNESDAY AFTERNOON ARE VERY ATTAINABLE...IN THE LOWER
80S...AND THE GFS 310K ISENTROPIC SURFACE SHOWS STRONG LIFT WITH
AGAIN A VERY MOIST AIR MASS WITH SPECIFIC HUMIDITIES OVER 9 G/KG.
MEANWHILE AT THE SURFACE A WARM FRONT STALLS ACROSS SOUTHERN
INDIANA...FURTHER ACTING AS A FOCUS FOR LOWER LEVEL CONVERGENCE.
THUS ANY HEATING ON WEDNESDAY SHOULD LEAD TO DEVELOPMENT. WILL
TREND POPS AT OR ABOVE MAVMOS...PARTICULARLY DURING THE AFTERNOON.
GIVEN THE EXPECTED CLOUDS AND RAIN...WILL TREND HIGHS AT OR BELOW
MAVMOS.
GFS DEPICTS A SHORT WAVE RIDING ACROSS THE WARM FRONT ACROSS THE
SOUTHERN PARTS OF THE FORECAST AREA ON WEDNESDAY NIGHT...AGAIN A
VERY WARM AND MOIST AIR MASS WILL REMAIN IN PLACE. FORECAST
SOUNDINGS ACROSS THE AREA ALSO INDICATE DEEP SATURATION BY
THURSDAY...AND NOW WITH PWATS IN EXCESS OF 2 INCHES. FAVORABLE
CAPE IS ALSO AVAILABLE. ALOFT IT APPEARS AS IF THE TROPICAL PLUME
THAT IS CURRENTLY FLOWING ACROSS THE PLAINS INTO THE DEEP SOUTH WILL
SHIFT EAST BY WEDNESDAY AND THURSDAY...ALLOWING THIS DEEPER
MOISTURE TO SURGE INTO INDIANA AND THE OHIO VALLEY...PARTICULARLY
ACROSS THE SOUTHERN PARTS OF OUR STATE. THUS WILL CONTINUE TO
RAISE POPS THROUGH THURSDAY NIGHT...TRENDING HIGHS COOLER THAN
MAVMOS AND LOWS WARMER...GIVEN THE EXPECTED CLOUDS AND RAIN.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
ISSUED AT 223 AM EDT TUE AUG 6 2013
LONG TERM PERIOD WILL BE CHARACTERIZED BY ZONAL OR WEAKLY CYCLONIC
FLOW...WITH SURFACE HIGH PRESSURE LIKELY TO BE IN CONTROL ACROSS
THE AREA FROM THE WEEKEND ONWARD. FRONTAL BOUNDARY WILL BE
GRADUALLY EXITING THE REGION EARLY IN THE PERIOD...AND WILL
CONTINUE TO CARRY POPS FRIDAY AND FRIDAY NIGHT BEFORE GOING DRY
THE REST OF THE PERIOD. ALLBLEND WANTS TO INSERT POPS LATE IN THE
WEEKEND BUT AT THIS POINT MODELS LOOK OVERAGGRESSIVE FOR THE WEAK
FEATURES NOTED WELL UPSTREAM.
ZONAL TO WEAKLY CYCLONIC FLOW SUGGESTS TEMPS NEAR TO A BIT BELOW
NORMAL...AND ALLBLEND HANDLED THIS WELL WITH FEW TWEAKS REQUIRED.
&&
.AVIATION /DISCUSSION FOR 141800Z TAF ISSUANCE/...
ISSUED AT 100 PM EDT SUN JUL 14 2013
MVFR CEILINGS LOOK LIKE THEY PERSIST ALL DAY PER MODEL
SOUNDINGS...CONVECTIVE CONDENSATION LEVELS AND CU DEVELOPMENT PROGS.
HOWEVER...WOULD NOT RULE OUT CEILINGS TO 3500 FEET AFTER 20Z IF ANY
BREAKS OCCUR IN THE OVERCAST. OTHERWISE...SHOULD BE DRY UNTIL AFTER
00Z. THEN...ILL-DEFINED WARM FRONT IS EXPECTED TO MOVE THROUGH AFTER
04Z. WOULD NOT RULE OUT STORMS ALONG AND AHEAD OF THE WARM
FRONT...HOWEVER WITH CONVERGENCE WEAK...AND LITTLE GOING ON NOW
AHEAD OF THE FRONT...WILL LEAVE OUT MENTION OF THUNDER OVERNIGHT AND
JUST GO WITH VCTS AFTER 20Z WEDNESDAY AT IND ASSOCIATED WITH A COLD
FRONT APPROACHING FROM THE NORTHWEST.
SOUTH AND SOUTHWEST WINDS WILL BE 10 KNOTS OR LESS THROUGH THE
PERIOD. FINALLY...WILL THROW IN MVFR FOG AFTER 09Z AS DEW POINTS
INCREASE TO AROUND 70 BEHIND THE WARM FRONT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...CP
SHORT TERM...PUMA
LONG TERM....NIELD
AVIATION...MK
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AREA FORECAST DISCUSSION
NWS GOODLAND KS
247 PM MDT TUE AUG 6 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 222 PM MDT TUE AUG 6 2013
LATEST WV IMAGERY AND RAP ANALYSIS SHOWS NW FLOW STILL IN PLACE
ACROSS THE NORTHERN AND CENTRAL CONUS...WITH A RIDGE CENTERED OVER
TEXAS AND A WEAKENED CLOSED LOW OVER SOUTHERN ARIZONA. A VERY
MOIST/UNSTABLE AIRMASS REMAINS IN PLACE OVER OUR CWA WITH TD VALUES
ACROSS NW KANSAS IN THE MID 60S TO LOW 70S...AND SB CAPE VALUES IN
THE 2000-4000 J/KG RANGE FROM THE WEST TO THE EAST. A SURFACE
TROUGH IS CURRENTLY CENTERED ALONG THE KS/CO BORDER...WITH LOWER
TD VALUES AND MUCH MORE STABLE AIRMASS TO THE WEST OF THIS
FEATURE.
THUNDERSTORMS HAVE ALREADY DEVELOPED ALONG THIS TROUGH AXIS
IN OUR FAR SW CWA. I WOULD EXPECT ADDITIONAL THUNDERSTORM
ACTIVITY TO INITIATE ALONG AND EAST OF THIS FEATURE THROUGH THIS
AFTERNOON AND EVENING. LATEST HRRR INDICATED ACTIVITY FORMING AHEAD OF
THIS AXIS AND FORMING INTO A CLUSTER/LINE AND SHIFTING TO THE
SOUTH AND EAST. BASED ON NAM/GFS SUPPORTING BETTER COVERAGE IN THE
SOUTH...WHICH IS IN LINE WITH SHORT RANGE GUIDANCE I KEPT THIS
TREND. A COLD FRONT WILL APPROACH THE CWA TONIGHT...WITH ELEVATED
INSTABILITY/GOOD MOISTURE LINGERING I DECIDED TO KEEP THUNDERSTORM
MENTION THROUGH THE NIGHT. CONSIDERING STORM MOTION WITH
INDIVIDUAL CELLS AND MOISTURE AVAILABILITY I AM CONCERNED WE COULD
SEE LOCALIZED FLASH FLOODING THIS AFTERNOON/EVENING IN ADDITION TO
SEVERE HAIL/WIND THREAT. COVERAGE IS A QUESTION THOUGH...WITH ANY
CLUSTER/LINE LIKELY BEGINNING TO PROPAGATE QUICKER AS IT FORMS A
COLD POOL IN OUR SOUTH. AS A RESULT WE MAY NOT ACTUALLY SEE AS
WIDESPREAD OF A THREAT OF FLASH FLOODING TODAY/TONIGHT.
WEDNESDAY...COLD FRONT WILL DROP SOUTH OF OUR CWA AND BE NEAR THE
KS/OK BORDER BY LATE WED AFTERNOON. DEEP MOIST EASTERLY FLOW
ALONG/NORTH OF THIS FEATURE COMBINED WITH INCREASING LARGE SCALE
ASCENT WILL SUPPORT NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS
ACROSS OUR SOUTHERN CWA. I AM CONCERNED THAT THE BEST COVERAGE MAY
BE TIED TO THE FRONT...WHICH WOULD PUT BETTER COVERAGE SOUTH OF OUR
CWA. HOWEVER THERE IS ENOUGH MOISTURE/FORCING ALOFT TO SUPPORT
HIGHER POPS ACROSS OUR SOUTHERN CWA IN THE AFTERNOON. A RESULT OF
THICK CLOUD COVER AND CAA THROUGH THE DAY WILL BE HIGH TEMPERATURES
WELL BELOW NORMAL (UPPER 60S TO MID 70S). PREVIOUS FORECAST HAD THIS
COOLER TREND...SO ONLY MINOR ADJUSTMENTS MADE. WHILE WE MAY NEED A
FLASH FLOOD WATCH FOR WED AFTERNOON DUE TO POSSIBLE TRAINING AND
WIDESPREAD HEAVY RAIN COVERAGE IN THE SOUTH...I FELT IT WAS BEST TO
CONCENTRATE PUBLIC ATTENTION ON ONGOING THUNDERSTORMS THIS
AFTERNOON/EVENING TO AVOID CONFUSION. WE MAY NEED TO ISSUE A WATCH
ON OVERNIGHT SHIFTS IF IT LOOKS LIKE OUR SOUTHERN CWA WILL REMAIN
FAVORABLE FOR A LARGE SCALE FLASH FLOOD THREAT.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 246 PM MDT TUE AUG 6 2013
FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT THE UPPER LEVEL WEATHER
PATTERN WILL REMAIN LARGELY UNCHANGED. AN UPPER LEVEL SHORT WAVE
TROUGH WILL MOVE OVER THE AREA WEDNESDAY NIGHT AND SLOWLY GLIDE
EASTWARD ACROSS THE AREA WITH ANOTHER ONE FOLLOWING IT OVER THE AREA
THURSDAY. WITH THE MID THROUGH UPPER LEVELS NEARLY TO TOTALLY
SATURATED AND THE RIGHT ENTRANCE OF THE 300MB JET OVER THE AREA AS
THESE TROUGHS MOVE THROUGH...AM THINKING THERE SHOULD BE A GOOD
CHANCE FOR SCATTERED TO WIDESPREAD RAINFALL DEVELOPMENT. THE BEST
AREA FOR PRECIP. CHANCES LOOKS TO BE OVER THE SOUTH HALF WHERE THE
BETTER FORCING AND LIFT WILL BE. PRECIP. CHANCES TAPER OFF THURSDAY
NIGHT FROM WEST TO EAST AS THE UPPER LEVEL TROUGH MOVES OUT OF THE
AREA AND DRIER AIR MOVES IN BEHIND IT. WEDNESDAY EVENING LOOKS TO
BE THE BEST CHANCE FOR SEVERE STORM DEVELOPMENT DUE TO 0-6KM SHEAR
OF 30-50KTS. HOWEVER ANY SEVERE STORMS THAT DEVELOP SHOULD REMAIN
CONFINED TO THE WESTERN AND SOUTHERN FRINGES OF THE AREA WHERE THE
BEST INSTABILITY WILL BE LOCATED. HEAVY RAINFALL WILL BE THE
PREDOMINANT THREAT DURING THIS TIMEFRAME DUE TO STORM MOTIONS OF
5-10KTS. A FLASH FLOOD WATCH WILL LIKELY BE NEEDED FROM WEDNESDAY
THROUGH THURSDAY MORNING FOR THE SOUTHERN TWO ROWS OF COUNTIES WHERE
STORM COVERAGE WILL BE MOST WIDESPREAD. AFTER SOME DISCUSSION WILL
HOLD OFF ISSUING THE WATCH FOR NOW TO PREVENT CONFUSION WITH ANY POTENTIAL
FLOODING THREAT FROM TODAY/S STORM ACTIVITY.
FOR FRIDAY THROUGH TUESDAY THE UPPER LEVEL RIDGE OVER THE SOUTHWEST
CONUS WILL BUILD A BIT FURTHER NORTH...WITH THE NORTHERN PERIPHARY
OF THE RIDGE OVER THE AREA. MULTIPLE UPPER LEVEL SHORT WAVE TROUGHS
WILL MOVE ACROSS THE AREA DURING THIS TIME CAUSING THERE TO BE
PRECIP. CHANCES FOR NEARLY EVERY DAY. MEANWHILE THE WEAK FRONT THAT
HAS BEEN WEST OF THE AREA WILL MOVE EAST ACROSS THE AREA DURING THE
WEEKEND INTO EARLY NEXT WEEK. AS A RESULT TEMPERATURES WILL RETURN
TO NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1144 AM MDT TUE AUG 6 2013
SCATTERED THUNDERSTORMS WILL DEVELOP ALONG TROUGH AXIS OVER NW
KS/SW NE THIS AFTERNOON AND INCREASE IN COVERAGE THROUGH THIS
EVENING AS THE ACTIVITY TRANSITIONS EAST. CURRENTLY COVERAGE IS
STILL TOO MUCH OF A QUESTION AT EITHER TERMINAL WITH BETTER
CHANCES FURTHER SOUTH AND EAST...SO I LIMITED MENTION TO VCTS.
LATE TONIGHT FOG/STRATUS IS EXPECTED TO REDEVELOP...WITH LOWER
CIGS/VIS AT BOTH TERMINALS BY SUNRISE. GUIDANCE CURRENTLY SUPPORTS
MVFR CONDITIONS...HOWEVER CONSIDERING THE MOIST NATURE OF THE
AIRMASS IF WINDS GO COMPLETELY CALM WE COULD SEE LOWER CONDITIONS
DEVELOP. FOR NOW I CHOSE TO STAY IN LINE WITH CURRENT
GUIDANCE...HOWEVER WE WILL NEED TO MONITOR THIS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JTL
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
222 PM MDT TUE AUG 6 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 222 PM MDT TUE AUG 6 2013
LATEST WV IMAGERY AND RAP ANALYSIS SHOWS NW FLOW STILL IN PLACE
ACROSS THE NORTHERN AND CENTRAL CONUS...WITH A RIDGE CENTERED OVER
TEXAS AND A WEAKENED CLOSED LOW OVER SOUTHERN ARIZONA. A VERY
MOIST/UNSTABLE AIRMASS REMAINS IN PLACE OVER OUR CWA WITH TD VALUES
ACROSS NW KANSAS IN THE MID 60S TO LOW 70S...AND SB CAPE VALUES IN
THE 2000-4000 J/KG RANGE FROM THE WEST TO THE EAST. A SURFACE
TROUGH IS CURRENTLY CENTERED ALONG THE KS/CO BORDER...WITH LOWER
TD VALUES AND MUCH MORE STABLE AIRMASS TO THE WEST OF THIS
FEATURE.
THUNDERSTORMS HAVE ALREADY DEVELOPED ALONG THIS TROUGH AXIS
IN OUR FAR SW CWA. I WOULD EXPECT ADDITIONAL THUNDERSTORM
ACTIVITY TO INITIATE ALONG AND EAST OF THIS FEATURE THROUGH THIS
AFTERNOON AND EVENING. LATEST HRRR INDICATED ACTIVITY FORMING AHEAD OF
THIS AXIS AND FORMING INTO A CLUSTER/LINE AND SHIFTING TO THE
SOUTH AND EAST. BASED ON NAM/GFS SUPPORTING BETTER COVERAGE IN THE
SOUTH...WHICH IS IN LINE WITH SHORT RANGE GUIDANCE I KEPT THIS
TREND. A COLD FRONT WILL APPROACH THE CWA TONIGHT...WITH ELEVATED
INSTABILITY/GOOD MOISTURE LINGERING I DECIDED TO KEEP THUNDERSTORM
MENTION THROUGH THE NIGHT. CONSIDERING STORM MOTION WITH
INDIVIDUAL CELLS AND MOISTURE AVAILABILITY I AM CONCERNED WE COULD
SEE LOCALIZED FLASH FLOODING THIS AFTERNOON/EVENING IN ADDITION TO
SEVERE HAIL/WIND THREAT. COVERAGE IS A QUESTION THOUGH...WITH ANY
CLUSTER/LINE LIKELY BEGINNING TO PROPAGATE QUICKER AS IT FORMS A
COLD POOL IN OUR SOUTH. AS A RESULT WE MAY NOT ACTUALLY SEE AS
WIDESPREAD OF A THREAT OF FLASH FLOODING TODAY/TONIGHT.
WEDNESDAY...COLD FRONT WILL DROP SOUTH OF OUR CWA AND BE NEAR THE
KS/OK BORDER BY LATE WED AFTERNOON. DEEP MOIST EASTERLY FLOW
ALONG/NORTH OF THIS FEATURE COMBINED WITH INCREASING LARGE SCALE
ASCENT WILL SUPPORT NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS
ACROSS OUR SOUTHERN CWA. I AM CONCERNED THAT THE BEST COVERAGE MAY
BE TIED TO THE FRONT...WHICH WOULD PUT BETTER COVERAGE SOUTH OF OUR
CWA. HOWEVER THERE IS ENOUGH MOISTURE/FORCING ALOFT TO SUPPORT
HIGHER POPS ACROSS OUR SOUTHERN CWA IN THE AFTERNOON. A RESULT OF
THICK CLOUD COVER AND CAA THROUGH THE DAY WILL BE HIGH TEMPERATURES
WELL BELOW NORMAL (UPPER 60S TO MID 70S). PREVIOUS FORECAST HAD THIS
COOLER TREND...SO ONLY MINOR ADJUSTMENTS MADE. WHILE WE MAY NEED A
FLASH FLOOD WATCH FOR WED AFTERNOON DUE TO POSSIBLE TRAINING AND
WIDESPREAD HEAVY RAIN COVERAGE IN THE SOUTH...I FELT IT WAS BEST TO
CONCENTRATE PUBLIC ATTENTION ON ONGOING THUNDERSTORMS THIS
AFTERNOON/EVENING TO AVOID CONFUSION. WE MAY NEED TO ISSUE A WATCH
ON OVERNIGHT SHIFTS IF IT LOOKS LIKE OUR SOUTHERN CWA WILL REMAIN
FAVORABLE FOR A LARGE SCALE FLASH FLOOD THREAT.
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 220 AM MDT TUE AUG 6 2013
MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THE SYNOPTIC
SCALE PATTERN DURING THE EXTENDED PERIOD. MINOR DIFFERENCES EMERGE
BY THE WEEKEND WHEN ECMWF IS STRONGER AND MORE AMPLIFIED THAN THE
GFS WITH UPPER RIDGE THAT BUILDS OVER OUR AREA. OTHERWISE...TYPICAL
DIFFERENCES EXIST WITH TIMING AND PLACEMENT OF SUBTLE SHORTWAVES IN
THE MID/UPPER FLOW LEADING TO UNCERTAINTY AS TO WHEN THE MOST
WIDESPREAD CONVECTION WILL OCCUR.
BY EARLY FRIDAY...DEEP MOISTURE WILL HAVE SHIFTED EAST OF THE AREA
AS RELATIVELY STRONG SHORTWAVE DEPARTS. COOL NORTHEASTERLY SURFACE
FLOW EARLY SHOULD SHIFT TO SOUTHEASTERLY LATE FRIDAY CAUSING A
RETURN OF LOW LEVEL MOISTURE AND HIGHER THETA-E VALUES. SOME
CONVECTION MAY DEVELOP FRIDAY AND FRIDAY EVENING IN THE VICINITY OF
LEE TROUGH / SURFACE CONVERGENCE OVER THE WESTERN PORTION OF THE
AREA. SIGNIFICANT FORCING IS ABSENT AND A RELATIVELY DRY COLUMN WITH
DEEP MIXED LAYER WILL LIKELY LIMIT COVERAGE OF CONVECTION. ON
SATURDAY...MOISTURE INCREASES FURTHER AND MID/UPPER FLOW
STRENGTHENS. LEE TROUGH SHARPENS AND MODELS INDICATE ONE OR TWO
SMALL PERTURBATIONS IN THE WESTERLY FLOW ALOFT...ALL OF WHICH
SUPPORTS A BETTER CHANCE OF CONVECTION ACROSS THE AREA. GFS IS MORE
PROGRESSIVE FOR SUNDAY AND MONDAY SHOWING DEEP MIXING ACROSS THE
WESTERN HALF OF THE AREA SUNDAY WITH CONVECTION CONFINED TO THE
EASTERN PORTION OF THE AREA WHERE BETTER MOISTURE RESIDES. ECMWF
HAS THE UPPER RIDGE AXIS FURTHER WEST AND THE GFS ENSEMBLE MEAN IS
IN BETWEEN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1144 AM MDT TUE AUG 6 2013
SCATTERED THUNDERSTORMS WILL DEVELOP ALONG TROUGH AXIS OVER NW
KS/SW NE THIS AFTERNOON AND INCREASE IN COVERAGE THROUGH THIS
EVENING AS THE ACTIVITY TRANSITIONS EAST. CURRENTLY COVERAGE IS
STILL TOO MUCH OF A QUESTION AT EITHER TERMINAL WITH BETTER
CHANCES FURTHER SOUTH AND EAST...SO I LIMITED MENTION TO VCTS.
LATE TONIGHT FOG/STRATUS IS EXPECTED TO REDEVELOP...WITH LOWER
CIGS/VIS AT BOTH TERMINALS BY SUNRISE. GUIDANCE CURRENTLY SUPPORTS
MVFR CONDITIONS...HOWEVER CONSIDERING THE MOIST NATURE OF THE
AIRMASS IF WINDS GO COMPLETELY CALM WE COULD SEE LOWER CONDITIONS
DEVELOP. FOR NOW I CHOSE TO STAY IN LINE WITH CURRENT
GUIDANCE...HOWEVER WE WILL NEED TO MONITOR THIS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BRB
AVIATION...DR
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1213 PM EDT TUE AUG 6 2013
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE COULD TRIGGER A SHOWER OR
THUNDERSTORM THIS AFTERNOON. OTHERWISE, HIGH PRESSURE WILL BUILD
ACROSS THE AREA TODAY AND MOVE EAST OF THE REGION ON WEDNESDAY AS
ANOTHER FRONT APPROACHES FROM THE SOUTHWEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
NOON UPDATE...CUMULUS HAVE FORMED ACROSS MANY AREAS. MODIFIED
CLOUDS COVER TO GO PARTLY CLOUDY IN NORTH CENTRAL AND WESTERN
AREAS WITH CUMULUS CLOUDS. REST OF THE FORECAST REMAINS ON TRACK.
PREVIOUS DISCUSSION...
DRIER AND MILDER TODAY.
A WEAK RIDGE OF HIGH PRES AT THE SFC IS SET TO MOVE OVER THE
REGION TODAY INTO TONIGHT. DRIER WEATHER W/MORE SUNSHINE WILL BE
SEEN TODAY W/TEMPERATURES RESPONDING INTO THE MID AND UPPER 70S.
THE CAVEAT TO THIS HOWEVER WILL BE A WEAK S/WV IN THE UPPER LEVELS
THAT WILL MOVE ACROSS THE STATE THIS AFTERNOON. THIS FEATURE IS
PICKED UP WELL BY THE 00Z NAM AND CANADIAN GEM PER 06Z ANALYSIS
OVER ONTARIO. IR SATL IMAGERY SHOWED SOME MID/HIGH CLOUDS ASSOCIATED
W/THIS FEATURE MOVING INTO WESTERN AND NORTHERN NYS. GFS/NAM
SOUNDINGS AS WELL AS THE GEM SHOW SOME MOISTURE AT THE 850MB LEVEL
W/THE MAJORITY OF THE RH ABOVE 700MBS. LATEST TRAJECTORIES BRING
SOME CLOUDINESS`S ACROSS PORTIONS OF WESTERN AND NORTHERN AREAS
TODAY. SOUNDINGS DO INDICATE SOME INSTABILITY AS LIS DROP TO -1 TO
-3 AND SBCAPES HIT CLOSE TO 500 JOULES. THERE IS SOME WEAK SHEAR
AT 0-6KM OF 15 KTS OR SO. 850-700MB LAPSE RATES FROM THE NAM ARE
CLOSE TO 7.0 C/KM AND SOME LLVL CONVERGENCE NOTED. ALL THIS COULD
BE ENOUGH TO TRIGGER SOME ISOLD SHOWERS OR PERHAPS A TSTM MAINLY
FOR THE WESTERN AND NWRN AREAS. THE NAM AND GFS HINT AT THIS TO
SET UP. EVEN THE 06Z HRRR SHOWS WIDELY SCATTERED TO ISOLD PRECIP.
THEREFORE, DECIDED TO ADD THE MENTION OF A SHOWER OR POSSIBLE
TSTM INTO LATE AFTERNOON(20%).
ACTIVITY WILL WIND DOWN IN THE EVENING AS THE S/WV MOVES TO THE E
AND LOSS OF HEATING. HIGH PRES IN THE GULF OF MAINE WILL RIDGE
OVER THE REGION TONIGHT. CLEARING SKIES AND COOLER TEMPERATURES
WILL ALLOW FOR SOME FOG TO DEVELOP. OVERNIGHT LOWS ARE EXPECTED
TO DROP BACK INTO THE UPPER 40S ACROSS THE N AND NW WHILE LOWER
50S SHOULD DO IT FOR CENTRAL AND DOWNEAST AREAS.SATURATED GROUND
AND DAYTIME HEATING WILL AID IN THE FOG DEVELOPMENT. ATTM, WENT
W/PATCHY FOG. DAYCREW CAN ASSESS THIS FURTHER TODAY.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL MOVE EAST OF THE REGION DURING WEDNESDAY. AFTER A
MAINLY SUNNY START TO THE DAY EXPECT INCREASING HIGH CLOUDS IN
ADVANCE OF THE NEXT TROF APPROACHING FROM THE WEST. THE MAIN
CHANGE TO THE WEDNESDAY FORECAST WAS TO DELAY THE ONSET OF ANY
SHOWERS GETTING INTO THE WESTERN AREAS UNTIL WEDNESDAY EVENING.
HIGH TEMPERATURES ON WEDNESDAY WILL BE CLOSE TO NORMAL FOR THIS
TIME OF YEAR WITH MID 70S TO NEAR 80 DEGREES ACROSS THE REGION.
CLOUDS WILL CONTINUE TO INCREASE WEDNESDAY NIGHT WITH SHOWERS
DEVELOPING FROM WEST TO EAST AFTER MIDNIGHT IN ADVANCE OF AN
APPROACHING WARM FRONT. LOWS WEDNESDAY NIGHT ARE EXPECTED TO RANGE
FROM THE MID TO UPPER 50S ACROSS THE REGION.
SHOWERS WILL CONTINUE TO BE LIKELY ON THURSDAY IN ADVANCE OF THE
APPROACHING COLD FRONT. HIGH TEMPERATURES ON THURSDAY WILL BE A BIT
BELOW NORMAL FOR THIS TIME OF YEAR DUE TO THE COMBINATION OF CLOUDS
AND SHOWERS. HIGHS WILL RANGE FROM THE UPPER 60S TO NEAR 70 DEGREES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE WEAK SURFACE COLD FRONT WILL SLOWLY CROSS THE REGION THURSDAY
NIGHT WITH SHOWERS TAPERING OFF FROM WEST TO EAST AFTER MIDNIGHT.
THE WEAKENING FRONT WILL STALL NEAR OR ALONG THE COAST LATER
THURSDAY NIGHT AND FRIDAY. LATEST MODEL GUIDANCE SUGGESTS FRIDAY
MAY BE A MAINLY DRY ALTHOUGH MOSTLY CLOUDY DAY.
A VIGOROUS 500MB LOW WILL MOVE EAST INTO QUEBEC LATER FRIDAY AND
SATURDAY. MODELS DIVERGE ON THE OVERALL SENSIBLE WEATHER FOR LATER
FRIDAY NIGHT AND INTO SATURDAY. THE 00Z OP RUN OF THE GFS DEVELOPS A
COMPACT SURFACE LOW ACROSS NYS FRIDAY NIGHT AND THEN TRACKS IT
ACROSS NEW ENGLAND AND ACROSS DOWNEAST MAINE FRIDAY NIGHT. 00Z EC IS
FURTHER SOUTH AND WEAKER WITH THE LOW KEEPING THE REGION MAINLY DRY.
FOR NOW HAVE KEPT CONTINUITY WITH GOING FORECAST AND WENT WITH LOW
CHANCE POPS FRIDAY NIGHT AND INTO SATURDAY.
COOLER AND DRIER AIR WILL WILL FOLLOW FOR LATE WEEKEND AND INTO
EARLY NEXT WEEK WITH TEMPERATURES AVERAGING BELOW SEASONAL FOR THIS
TIME OF YEAR.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: VFR THROUGH TONIGHT FOR ALL TERMINALS. THERE IS
POTENTIAL FOR SOME FOG TO DEVELOP LATE TONIGHT MAINLY ACROSS THE
NORTHERN TERMINALS DUE TO THE WET GROUND AND CLEARING. CONDITIONS
COULD BRIEFLY DROP TO MVFR OR PERHAPS IFR BY EARLY WEDNESDAY MORNING.
SHORT TERM: VFR WEDNESDAY. MVFR WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT IN SHOWERS. VFR FRIDAY AND SATURDAY.
&&
.MARINE...
NEAR TERM: NO HEADLINES THIS TERM. WINDS WILL TURN TO THE SW LATER
TODAY AND AVERAGE 10 KT OR SO. WAVE HEIGHTS WILL STAY AT 2-3 FT
MAINLY AWAY FROM THE INTRA-COASTAL ZONE.
SHORT TERM: WINDS/SEAS SHOULD REMAIN BELOW SCA LEVELS FOR THIS
TERM.
&&
.MARINE...
NEAR TERM:
SHORT TERM:
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...BLOOMER
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
655 PM EDT TUE AUG 6 2013
.AVIATION...
//DISCUSSION...
DIURNALLY DRIVEN SHOWERS WILL FADE AT THE BEGINNING OF THE FORECAST
LEAVING DRY CONDITIONS OVERNIGHT AS NEXT AREA OF SHOWERS/STORMS WELL
TO THE WEST OVER MN/WI MOST LIKELY DROP SOUTHEAST AND BYPASS MUCH OF
LOWER MICHIGAN OVERNIGHT. RESIDUAL LOW LEVEL MOISTURE WILL BRING
PATCHY FOG BY DAYBREAK WEDNESDAY...BUT VSBYS SHOULD HOLD IN THE 4 TO
6SM RANGE. THE NEXT CHANCE OF SHRAS/TSRAS WILL COME WITH THE PASSAGE
OF A SURFACE TROUGH BETWEEN 16Z-21Z WEDNESDAY...PROGRESSING FROM
KMBS TO THE I-94 TERMINALS DURING THE COURSE OF THE AFTERNOON.
FOR DTW...WITH CURRENT CONVECTION LIFTING NORTHEAST...THE NEXT
CHANCE OF SHRAS/TSRAS WILL HOLD OFF UNTIL 20Z-22Z WEDNESDAY AS
ACTIVITY DEVELOPS ALONG AN APPROACHING SURFACE TROUGH. OTHER THAN
THIS...THE ONLY MINOR CONCERN WILL BE THE POTENTIAL OF FOG LATE
TONIGHT...BUT EVEN WITH THIS...VSBYS SHOULD REMAIN GENERALLY 5SM.
//DTW THRESHOLD THREATS...
* LOW CONFIDENCE IN CEILINGS AOB 5000 FEET WEDNESDAY AFTERNOON.
* LOW CONFIDENCE IN TIMING/COVERAGE OF THUNDERSTORMS WEDNESDAY
AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 402 PM EDT TUE AUG 6 2013
SHORT TERM...THROUGH TONIGHT
CURRENT OBSERVATIONS AND SATELLITE TRENDS SHOW CLOUDS OVER
SOUTHEAST MICHIGAN...ALONG WITH RAIN SHOWERS CONTINUING TO MOVE OFF
TO THE NORTHEAST. AREAS OF RAIN SHOWERS WERE ABLE TO DEVELOP OVER
THE WESTERN CWA AND MAINTAIN MOMENTUM AS AN AREA OF 500 MB VORTICITY
MOVED THROUGH AND LOW LEVEL LAPSE RATES INCREASED TO AROUND 6.5
C/KM. A BREAK IN THE RAIN WILL BE SEEN BEFORE ANOTHER ROUND MOVES
THROUGH ROUGHLY THE SAME AREA LATE THIS AFTERNOON AND EVENING.
LATEST RUN OF THE HRRR IS ADVERTISING MORE SHOWERS BETWEEN 20Z-03Z.
HAVE SLIGHTLY INCREASED POPS IN AREAS MAINLY NORTH OF METRO DETROIT
DURING THIS TIMEFRAME. EXPECTING MODERATE RAIN SHOWERS AS WAS SEEN
THIS MORNING...WITH A SLIGHT CHANCE FOR ISOLATED THUNDERSTORMS.
EXPECTING ANY THUNDERSTORMS THAT DO DEVELOP TO REMAIN BELOW SEVERE
CRITERIA. HAVE BEEN MONITORING A SMALL BREAK IN CLOUDS OVER THE
PAST FEW HOURS WHICH HAS ALLOWED INSTABILITY TO INCREASE. LOOKING
AT THE SPC MESOANALYSIS...LOW LEVEL LAPSE RATES HAVE INCREASED TO
AROUND 7-7.5 WITH SBCAPE ONLY AROUND 500 J/KG. SHOWERS HAVE STARTED
TO DEVELOP JUST SOUTH OF THE LANSING AND WILL CONTINUE TO MOVE OFF
TO THE NORTHEAST. CHANCES FOR PRECIPITATION WILL DIMINISH WITH THE
LOSS OF DIURNAL HEATING. OVERNIGHT...SOUTHEAST MICHIGAN WILL START
FEELING THE INFLUENCE FROM THE UPPER LEVEL JET STREAK AS THE LOW
PRESSURE CURRENTLY OVER THE UPPER MIDWEST SAGS EAST. HIGHER CLOUDS
FROM CONVECTION CURRENTLY OVER WISCONSIN WILL STREAM IN OVER SE
MICHIGAN AND WITH WINDS OUT OF THE SOUTH..WILL KEEP LOWS WARMER THAN
THE PREVIOUS MORNING. ANOTHER AREA OF VORTICITY ASSOCIATED AHEAD OF
THE COLD FRONT IS SET TO ROTATE DOWN ACROSS THE UPPER GREAT LAKES
WEDNESDAY MORNING...INCREASING THE CHANCES FOR MORE WIDESPREAD
SHOWERS AND THUNDERSTORMS.
LONG TERM...WEDNESDAY THROUGH MONDAY
NOT MUCH CHANGE IN THE LONG TERM THROUGH THE PERIOD AS THE DOMINATE
CUTOFF UPPER LOW CONTINUES TO WOBBLE ABOUT EASTERN CANADA. MODELS
HAVE HAD AMPLE TIME TO LATCH ONTO THIS FEATURE WHICH HAS LED TO GOOD
AGREEMENT WITH THE OVERALL PATTERN. A SECOND UPPER LOW OVER THE WEST
COAST IS STEERING THE SOUTHERN STREAM OF THE JET UP FROM SOUTHERN
CALIFORNIA THROUGH THE CENTRAL PORTION OF THE CONUS TO THE GREAT
LAKES. THIS WILL BRING ABOUT SOME PHASING OF THE TWO STREAMS OVER
THE GREAT LAKES THROUGH THE WEEKEND. GENERAL NW PROGRESSIVE FLOW
WILL SEND A SERIES OF SHORTWAVES THROUGH THE REGION PRODUCING A FEW
SHOTS AT PRECIP BUT DRY AIR AND HIGH IN THE WAKE OF THE BEST FRONT
ON WEDNESDAY WILL PREVENT ANY SIGNIFICANT EVENTS.
FOR WEDNESDAY...WE MAY HAVE A COUPLE ROUNDS OF PRECIP IN THE HOPPER
AS MODELS INDICATE A MORNING COMPLEX WITH A LEAD SHORTWAVE FOLLOWED
BY A SECOND ROUND ALONG THE COLD FRONT ITSELF LATER IN THE
AFTERNOON/EVENING. BOTH THE NAM AND HRRR SUGGEST THE MORNING STORM
COMPLEX WILL TRACK GENERALLY THROUGH CHI AND IND KEEPING THE BULK OF
PRECIP TO OUR SOUTH WITH SOME MORE SCATTERED SHOWERS UP AROUND SE
MI. THIS WILL COME MORE IN LINE THROUGH THE EVENING AS WE SEE IF/HOW
THE COMPLEX ACTUALLY COMES TOGETHER. REGARDLESS THERE WILL BE A FAIR
AMOUNT OF CLOUD COVER TO CONTEND WITH EARLY IN THE DAY. AS IS
USUALLY THE CASE FOR THE AREA...THE AMOUNT OF CLOUDS AND HOW LONG
THEY STICK AROUND WILL HELP DICTATE WHERE WE STAND WITH CONVECTION
LATER IN THE DAY ALONG THE FRONT. EVEN WITH THE NAM KEEPING A FAIR
AMOUNT OF CLOUDS AROUND THROUGH THE DAY IT STILL GENERATES UP TO
1500 K/KG OF CAPE WITH 30-40 KNOTS OF BULK SHEAR. GFS IS A LITTLE
MORE BULLISH WITH CLEARING WHICH THEN ALLOWS MORE INSTABILITY TO
BUILD ADVERTISING JUST OVER 2000 J/KG OF CAPE. ANOTHER PROBLEM WITH
THE SETUP IS THAT THE PARENT SFC LOW WILL BE LIFTING TO THE NORTH
THROUGH THE DAY WHICH SLOWLY ORIENTATES THE FRONT PARALLEL TO THE
FLOW REDUCING SFC CONVERGENCE ALONG THE FRONT. LI/S ARE ON THE LOW
SIDE AS WELL ONLY REACHING AROUND -3C. FRONTAL TIMING WILL BE
FAVORABLE GIVING SE MI THE FULL DAY TO CLEAR OUT AND HEAT UP BEFORE
THE FRONT ROLLS THROUGH SO CHANCES FOR STRONG ORGANIZED STORMS WILL
GET LARGER AS YOU TRACK FROM MBS TO DTW. SPC IS ON TRACK WITH THIS
THINKING KEEPING ONLY FAR SE MI...SE OF A LINE FROM PORT HURON TO
COLDWATER...WITHIN THE SLIGHT RISK AREA. TEMPS SHOULD REACH 80+ FOR
MOST LOCATIONS AS A DECENT THETA E RIDGE BUILDS IN AHEAD OF THE
FRONT. 850 MB TEMPS ARE STILL PROGGED TO REACH 16C BY THE AFTERNOON
HOURS.
IN THE WAKE OF THE FRONT A HIGH PRESSURE SYSTEM WILL SLIDE INTO THE
REGION BRINGING COOLER DRIER AIR IN FROM CANADA THROUGH SATURDAY. A
WEAK FRONT WILL DROP THROUGH FRIDAY NIGHT WITH LITTLE CHANCE OF
PRODUCING MORE THAN A CHANCE FOR MOST LOCATIONS. A SHORTWAVE ON
SUNDAY WILL WORK OVER THE AREA BUT WILL LIKELY STRUGGLE TO PRODUCE
ANY PRECIP WITH DRY AIR PRESENT. NORTHERLY FLOW WITH THE MAIN
BAROCLINIC ZONE TO OUR SOUTH WILL KEEP TEMPERATURES ON THE COOL SIDE
THROUGH MUCH OF THE EXTENDED. THE PATTERN HAS YIELDED AN EXTENSIVE
PERIOD OF 70S AND DO NOT SEE THIS CHANGING.
MARINE...
LOW PRESSURE WILL SAG OVER THE UPPER GREAT LAKES PULLING A COLD
FRONT THROUGH THE AREA LATER WEDNESDAY EVENING. SOUTHERLY WINDS
AHEAD OF THE FRONT WILL CONTINUE OVERNIGHT AND THROUGH WEDNESDAY.
WARMER AIR ASSOCIATED WITH THE SOUTHERLY WINDS WILL KEEP CONDITIONS
STABLE OVER THE WATERS. CHANCE FOR MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS WILL INCREASE STARTING WEDNESDAY MORNING. WINDS WILL
DIMINISH THURSDAY INTO FRIDAY AS HIGH PRESSURE OVERSPREADS THE
REGION. ANOTHER COLD FRONT IS FORECAST TO TRAVERSE THE LAKES FRIDAY
NIGHT. A PUSH OF MUCH COLDER AIR BEHIND THIS FRONT IS LIKELY TO
CAUSE STRENGTHENING OF THE POST FRONTAL NORTHWEST WINDS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....DG
SHORT TERM...SS
LONG TERM....DRK
MARINE.......SS
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
402 PM EDT TUE AUG 6 2013
.SHORT TERM...THROUGH TONIGHT
CURRENT OBSERVATIONS AND SATELLITE TRENDS SHOW CLOUDS OVER
SOUTHEAST MICHIGAN...ALONG WITH RAIN SHOWERS CONTINUING TO MOVE OFF
TO THE NORTHEAST. AREAS OF RAIN SHOWERS WERE ABLE TO DEVELOP OVER
THE WESTERN CWA AND MAINTAIN MOMENTUM AS AN AREA OF 500 MB VORTICITY
MOVED THROUGH AND LOW LEVEL LAPSE RATES INCREASED TO AROUND 6.5
C/KM. A BREAK IN THE RAIN WILL BE SEEN BEFORE ANOTHER ROUND MOVES
THROUGH ROUGHLY THE SAME AREA LATE THIS AFTERNOON AND EVENING.
LATEST RUN OF THE HRRR IS ADVERTISING MORE SHOWERS BETWEEN 20Z-03Z.
HAVE SLIGHTLY INCREASED POPS IN AREAS MAINLY NORTH OF METRO DETROIT
DURING THIS TIMEFRAME. EXPECTING MODERATE RAIN SHOWERS AS WAS SEEN
THIS MORNING...WITH A SLIGHT CHANCE FOR ISOLATED THUNDERSTORMS.
EXPECTING ANY THUNDERSTORMS THAT DO DEVELOP TO REMAIN BELOW SEVERE
CRITERIA. HAVE BEEN MONITORING A SMALL BREAK IN CLOUDS OVER THE
PAST FEW HOURS WHICH HAS ALLOWED INSTABILITY TO INCREASE. LOOKING
AT THE SPC MESOANALYSIS...LOW LEVEL LAPSE RATES HAVE INCREASED TO
AROUND 7-7.5 WITH SBCAPE ONLY AROUND 500 J/KG. SHOWERS HAVE STARTED
TO DEVELOP JUST SOUTH OF THE LANSING AND WILL CONTINUE TO MOVE OFF
TO THE NORTHEAST. CHANCES FOR PRECIPITATION WILL DIMINISH WITH THE
LOSS OF DIURNAL HEATING. OVERNIGHT...SOUTHEAST MICHIGAN WILL START
FEELING THE INFLUENCE FROM THE UPPER LEVEL JET STREAK AS THE LOW
PRESSURE CURRENTLY OVER THE UPPER MIDWEST SAGS EAST. HIGHER CLOUDS
FROM CONVECTION CURRENTLY OVER WISCONSIN WILL STREAM IN OVER SE
MICHIGAN AND WITH WINDS OUT OF THE SOUTH..WILL KEEP LOWS WARMER THAN
THE PREVIOUS MORNING. ANOTHER AREA OF VORTICITY ASSOCIATED AHEAD OF
THE COLD FRONT IS SET TO ROTATE DOWN ACROSS THE UPPER GREAT LAKES
WEDNESDAY MORNING...INCREASING THE CHANCES FOR MORE WIDESPREAD
SHOWERS AND THUNDERSTORMS.
&&
.LONG TERM...WEDNESDAY THROUGH MONDAY
NOT MUCH CHANGE IN THE LONG TERM THROUGH THE PERIOD AS THE DOMINATE
CUTOFF UPPER LOW CONTINUES TO WOBBLE ABOUT EASTERN CANADA. MODELS
HAVE HAD AMPLE TIME TO LATCH ONTO THIS FEATURE WHICH HAS LED TO GOOD
AGREEMENT WITH THE OVERALL PATTERN. A SECOND UPPER LOW OVER THE WEST
COAST IS STEERING THE SOUTHERN STREAM OF THE JET UP FROM SOUTHERN
CALIFORNIA THROUGH THE CENTRAL PORTION OF THE CONUS TO THE GREAT
LAKES. THIS WILL BRING ABOUT SOME PHASING OF THE TWO STREAMS OVER
THE GREAT LAKES THROUGH THE WEEKEND. GENERAL NW PROGRESSIVE FLOW
WILL SEND A SERIES OF SHORTWAVES THROUGH THE REGION PRODUCING A FEW
SHOTS AT PRECIP BUT DRY AIR AND HIGH IN THE WAKE OF THE BEST FRONT
ON WEDNESDAY WILL PREVENT ANY SIGNIFICANT EVENTS.
FOR WEDNESDAY...WE MAY HAVE A COUPLE ROUNDS OF PRECIP IN THE HOPPER
AS MODELS INDICATE A MORNING COMPLEX WITH A LEAD SHORTWAVE FOLLOWED
BY A SECOND ROUND ALONG THE COLD FRONT ITSELF LATER IN THE
AFTERNOON/EVENING. BOTH THE NAM AND HRRR SUGGEST THE MORNING STORM
COMPLEX WILL TRACK GENERALLY THROUGH CHI AND IND KEEPING THE BULK OF
PRECIP TO OUR SOUTH WITH SOME MORE SCATTERED SHOWERS UP AROUND SE
MI. THIS WILL COME MORE IN LINE THROUGH THE EVENING AS WE SEE IF/HOW
THE COMPLEX ACTUALLY COMES TOGETHER. REGARDLESS THERE WILL BE A FAIR
AMOUNT OF CLOUD COVER TO CONTEND WITH EARLY IN THE DAY. AS IS
USUALLY THE CASE FOR THE AREA...THE AMOUNT OF CLOUDS AND HOW LONG
THEY STICK AROUND WILL HELP DICTATE WHERE WE STAND WITH CONVECTION
LATER IN THE DAY ALONG THE FRONT. EVEN WITH THE NAM KEEPING A FAIR
AMOUNT OF CLOUDS AROUND THROUGH THE DAY IT STILL GENERATES UP TO
1500 K/KG OF CAPE WITH 30-40 KNOTS OF BULK SHEAR. GFS IS A LITTLE
MORE BULLISH WITH CLEARING WHICH THEN ALLOWS MORE INSTABILITY TO
BUILD ADVERTISING JUST OVER 2000 J/KG OF CAPE. ANOTHER PROBLEM WITH
THE SETUP IS THAT THE PARENT SFC LOW WILL BE LIFTING TO THE NORTH
THROUGH THE DAY WHICH SLOWLY ORIENTATES THE FRONT PARALLEL TO THE
FLOW REDUCING SFC CONVERGENCE ALONG THE FRONT. LI/S ARE ON THE LOW
SIDE AS WELL ONLY REACHING AROUND -3C. FRONTAL TIMING WILL BE
FAVORABLE GIVING SE MI THE FULL DAY TO CLEAR OUT AND HEAT UP BEFORE
THE FRONT ROLLS THROUGH SO CHANCES FOR STRONG ORGANIZED STORMS WILL
GET LARGER AS YOU TRACK FROM MBS TO DTW. SPC IS ON TRACK WITH THIS
THINKING KEEPING ONLY FAR SE MI...SE OF A LINE FROM PORT HURON TO
COLDWATER...WITHIN THE SLIGHT RISK AREA. TEMPS SHOULD REACH 80+ FOR
MOST LOCATIONS AS A DECENT THETA E RIDGE BUILDS IN AHEAD OF THE
FRONT. 850 MB TEMPS ARE STILL PROGGED TO REACH 16C BY THE AFTERNOON
HOURS.
IN THE WAKE OF THE FRONT A HIGH PRESSURE SYSTEM WILL SLIDE INTO THE
REGION BRINGING COOLER DRIER AIR IN FROM CANADA THROUGH SATURDAY. A
WEAK FRONT WILL DROP THROUGH FRIDAY NIGHT WITH LITTLE CHANCE OF
PRODUCING MORE THAN A CHANCE FOR MOST LOCATIONS. A SHORTWAVE ON
SUNDAY WILL WORK OVER THE AREA BUT WILL LIKELY STRUGGLE TO PRODUCE
ANY PRECIP WITH DRY AIR PRESENT. NORTHERLY FLOW WITH THE MAIN
BAROCLINIC ZONE TO OUR SOUTH WILL KEEP TEMPERATURES ON THE COOL SIDE
THROUGH MUCH OF THE EXTENDED. THE PATTERN HAS YIELDED AN EXTENSIVE
PERIOD OF 70S AND DO NOT SEE THIS CHANGING.
&&
.MARINE...
LOW PRESSURE WILL SAG OVER THE UPPER GREAT LAKES PULLING A COLD
FRONT THROUGH THE AREA LATER WEDNESDAY EVENING. SOUTHERLY WINDS
AHEAD OF THE FRONT WILL CONTINUE OVERNIGHT AND THROUGH WEDNESDAY.
WARMER AIR ASSOCIATED WITH THE SOUTHERLY WINDS WILL KEEP CONDITIONS
STABLE OVER THE WATERS. CHANCE FOR MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS WILL INCREASE STARTING WEDNESDAY MORNING. WINDS WILL
DIMINISH THURSDAY INTO FRIDAY AS HIGH PRESSURE OVERSPREADS THE
REGION. ANOTHER COLD FRONT IS FORECAST TO TRAVERSE THE LAKES FRIDAY
NIGHT. A PUSH OF MUCH COLDER AIR BEHIND THIS FRONT IS LIKELY TO
CAUSE STRENGTHENING OF THE POST FRONTAL NORTHWEST WINDS.
&&
.AVIATION...ISSUED 117 PM EDT TUE AUG 6 2013
//DISCUSSION...
CLOUDS AND LOW LEVEL MOISTURE WILL CONTINUE TO STREAM INTO THE AREA
THROUGH WEDNESDAY MORNING AS A COLD FRONT APPROACHES. THERE IS
ANOTHER CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS EARLY THIS
EVENING. CHANCES ARE SLIGHTLY BETTER AT PNT/FNT TAF SITES AND SO
HAVE INCLUDED THAT IN THE TAFS. HOWEVER...WITH ANY PRECIPITATION
THAT DOES DEVELOP...AM EXPECTING SHOWERS LIKE WHAT WAS SEEN EARLIER
THIS AFTERNOON DUE TO THE WARMER AIR IN THE MID LEVELS KEEPING
THINGS FROM DEVELOPING TOO MUCH. THERE IS STILL A SLIGHT CHANCE OF AN
ISOLATED THUNDERSTORM...ESPECIALLY IF BREAKS IN THE CLOUDS DEVELOP
FOR ANY LENGTH OF TIME. A BREAK IN THE PRECIPITATION WILL BE SEEN
OVERNIGHT AND WITH THE AMOUNT OF LOW LEVEL MOISTURE DO HAVE THE
POTENTIAL TO SEE AREAS OF DECREASED VISIBILITY. RAIN AND
THUNDERSTORMS WILL ONCE AGAIN AFFECT THE AREA WEDNESDAY AS THE COLD
FRONT WORKS CLOSER AND IS EXPECTED TO PUSH THROUGH AFTER 00Z
THURSDAY.
FOR DTW...CONFIDENCE IS TO LOW TO MENTION ANY THUNDERSTORMS IN THE
TAFS LATER THIS AFTERNOON...HOWEVER WILL KEEP MONITORING FOR
CHANGES. WITH THE AMOUNT OF LOW LEVEL MOISTURE STILL PRESENT
OVERNIGHT...THERE WILL BE AN INCREASED CHANCE FOR VISIBILITIES TO
DROP UNDER 6SM.
//DTW THRESHOLD THREATS...
* MODERATE CONFIDENCE IN CEILING BELOW 5000 FT OVERNIGHT.
* LOW CONFIDENCE IN TIMING/COVERAGE OF SHOWERS THIS EVENING.
* LOW CONFIDENCE IN THUNDERSTORMS LATER THIS AFTERNOON INTO EARLY EVENING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...SS
LONG TERM....DRK
MARINE.......SS
AVIATION.....SS
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
352 PM EDT TUE AUG 6 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 347 PM EDT TUE AUG 6 2013
A COLD FRONT WILL MOVE THROUGH THE NORTHERN PLAINS TONIGHT AND
APPROACH LAKE MICHIGAN TOWARDS DAYBREAK. THE FRONT WILL SWEEP
THROUGH LOWER MICHIGAN ON WEDNESDAY BRINGING COOLER AND DRIER AIR
INTO THE REGION FOR WEDNESDAY NIGHT AND THURSDAY. SHOWER AND STORMS
WILL ACCOMPANY THE FRONT BOTH TONIGHT AND WEDNESDAY. SOME OF THE
STORMS MAY BE ON THE STRONG SIDE WEDNESDAY AFTERNOON SOUTH AND EAST
OF GRAND RAPIDS. HIGHS ON WEDNESDAY WILL PUSH INTO THE UPPER 70S AND
LOWER 80S. THE UPCOMING WEEKEND LOOKS DRY WITH HIGHS IN THE 70S.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 347 PM EDT TUE AUG 6 2013
MAIN CONCERNS IN THE SHORT TERM ARE RELATED TO CONVECTION TONIGHT
AND WEDNESDAY. CURRENT THINKING IS WE WILL SEE SOME SCATTERED
SHOWERS AND STORMS BETWEEN NOW AND MIDNIGHT...WITH BETTER CHANCES
OCCURRING LATE. THE LATEST HRRR GUIDANCE WOULD SUGGEST WE WILL SEE A
THUNDERSTORM COMPLEX ROLL EAST OUT OF WISCONSIN AND MOVE INTO
CENTRAL LOWER MICHIGAN OVERNIGHT. THIS SEEMS PLAUSIBLE GIVEN THE
CONFIGURATION OF THE 850MB LLJ. NOT EXPECTING SEVERE WEATHER AT THIS
TIME...BUT THE SIMULATED REFLECTIVITY IS IN THE FORM OF A SQUALL
LINE.
EXPECT SCATTERED SHOWERS AND STORMS TO BE OVER A DECENT AMOUNT OF
THE FORECAST AREA BETWEEN 09Z AND 15Z AS UPSTREAM RESIDUAL
CONVECTION SLIDES INTO LOWER MICHIGAN OR DEVELOPS OVERHEAD ON THE
LLJ.
SHOWERS AND STORMS SHOULD REFOCUS MIDDAY ALONG THE COLD FRONT THAT
SHOULD BISECT THE CWA. STRONG STORMS ARE POSSIBLE IN THE EASTERN CWA
TOMORROW AFTERNOON WITH 40 KNOTS OF DEEP LAYER SHEAR AND THE
POTENTIAL FOR SOME BREAKS IN THE OVERCAST AHEAD OF THE MORNING
STORMS. CLOUD COVER TOMORROW MORNING WILL DETERMINE THE STRENGTH OF
THE AFTERNOON CONVECTION AS DEEP MOISTURE WILL BE IN PLACE.
THE SHOWERS AND STORMS SHOULD EXIT TO THE EAST EARLY IN THE EVENING
AS THE FRONT SWEEPS THROUGH. MAINLY DRY WEATHER IS THEN FORECAST
FROM WEDNESDAY EVENING THROUGH THURSDAY NIGHT. THERE IS SOME SMALL
POTENTIAL FOR SHOWERS AND STORMS IN THE SOUTH THURSDAY NIGHT...BUT
THIS ACTIVITY MAY JUST MISS THE AREA TO THE SOUTH PER RECENT MODEL
TRENDS.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 347 PM EDT TUE AUG 6 2013
THE POLAR VORTEX OVER EASTERN CANADA WILL CONTINUE TO PLAY A ROLE IN
OUR WEATHER THROUGH THE EXTENDED PERIOD. A STRONG SHORT WAVE MOVING
ACROSS ONTARIO WILL PUSH A COLD FRONT THROUGH THE CWA FRIDAY SENDING
ANOTHER PUSH OF COOLER AIR SOUTH ACROSS THE CWA FOR THE WEEKEND. THE
LACK OF DEEP MOISTURE AND INSTABILITY WILL RESULT IN LIGHT SHOWERS
AT BEST FRIDAY.
MUCH OF THE WEEKEND LOOKS DRY WITH HIGHS IN THE MID 70S AND
DEWPOINTS IN THE 50S AS SFC HIGH PRESSURE SETTLES OVER THE GREAT
LAKES.
ANOTHER SHORT WAVE WILL DROP SOUTH FROM NORTHERN ONTARIO DURING THE
MONDAY/TUESDAY TIME FRAME. SIMILAR TO THE LAST FRONT...THERE WON/T
BE MUCH MOISTURE WITH THIS FRONT EITHER. LOW CHANCES OF SHOWERS WILL
COVER THIS TROUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 352 PM EDT TUE AUG 6 2013
LATEST NEPH ANALYSIS SHOWS MVFR CONDITONS ACROSS MUCH OF THE
MIDWEST. ERN LWR MI WAS MAINLY VFR AND KJXN WAS JUST ON THE
EDGE...EXPLAINING WHY THEY KEEP OSCILLATING BETWEEN IFR/MVFR. GIVEN
THE SW WINDS I KEPT KJXN MVFR BUT THEY COULD CONTINUE TO OSCILLATE
THROUGH THE AFTERNOON. LIGHT SHOWERS ARE POSSIBLE ACROSS THE SRN TAF
SITES THIS AFTERNOON. OVERALL...LOOK FOR VFR TO DEVELOP BY THIS
EVENING WITH TSRA POSSIBLE OVERNIGHT AHEAD OF AN APPROACHING COLD
FRONT.
&&
.MARINE...
ISSUED AT 347 PM EDT TUE AUG 6 2013
HAVE HELD OFF ON ANY SMALL CRAFT ADVISORIES OR BEACH HAZARDS
STATEMENTS AS THE WINDS AND WAVES IN TODAY/S MODEL RUNS ARE NOT AS
SIGNIFICANT AS LAST NIGHT OR YESTERDAY. IT APPEARS AT THIS POINT IN
BOTH THE SOUTHERLY FLOW TONIGHT AND THE NORTH FLOW BEHIND THE FRONT
TOMORROW THAT WE REMAIN BELOW CRITERIA. AM A BIT CONCERNED THOUGH
BASED ON THE WINDS SEEN IN BUFKIT THAT WE WON/T INDEED BE HIGHER
BOTH TONIGHT...WEDNESDAY AND WEDNESDAY NIGHT. WE WILL SEE AS WE
PROGRESS THROUGH THE EVENING AS BUFKIT WOULD SUGGEST INCREASING
WINDS IN THE 04Z-08Z TIME FRAME. WE PLAY THINGS LOWER AT THIS POINT
BUT WATCH CAUTIOUSLY AND CLOSELY.
&&
.HYDROLOGY...
ISSUED AT 347 PM EDT TUE AUG 6 2013
NO SIGNIFICANT HYDRO ISSUES EXPECTED THROUGH THE NEXT COUPLE DAYS
WITH NEAR NORMAL FLOWS IN PLACE NOW AND FORECAST RAINFALL IS NOT
EXPECTED TO BE WIDESPREAD OR OVERLY HEAVY. RAINFALL LAST NIGHT WAS
QUITE LIMITED AS WELL SO WE ARE STARTING OFF WITH FAIRLY DRY GROUND
OVER MUCH OF THE AREA. RAINFALL IS EXPECTED TONIGHT THROUGH
WEDNESDAY...BUT IT WILL BE ASSOCIATED WITH THUNDERSTORM COMPLEXES
THAT WILL BE TRAVERSING THE AREA AT A DECENT CLIP. THE FIRST COMES
LATE TONIGHT AS STORMS THAT FIRE IN MINNESOTA THIS EVENING TRY TO
MOVE ACROSS LAKE MICHIGAN AFTER MIDNIGHT. THESE STORMS WILL LIKELY
AFFECT CENTRAL LOWER MICHIGAN. SCATTERED SHOWERS AND STORMS WILL
THEN TRAVERSE MUCH OF THE AREA LATE TONIGHT AND WEDNESDAY MORNING. A
MORE CONCENTRATED AREA OF SHOWERS AND STORMS WILL AFFECT THE EASTERN
TO SOUTHEASTERN HALF OF THE AREA WEDNESDAY AFTERNOON. WE COULD SEE
GENERAL RAINFALL AMOUNTS ON THE ORDER OF A QUARTER TO HALF INCH WITH
ISOLATED AMOUNTS AROUND AN INCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...93
AVIATION...93
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
347 PM EDT TUE AUG 6 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 347 PM EDT TUE AUG 6 2013
A COLD FRONT WILL MOVE THROUGH THE NORTHERN PLAINS TONIGHT AND
APPROACH LAKE MICHIGAN TOWARDS DAYBREAK. THE FRONT WILL SWEEP
THROUGH LOWER MICHIGAN ON WEDNESDAY BRINGING COOLER AND DRIER AIR
INTO THE REGION FOR WEDNESDAY NIGHT AND THURSDAY. SHOWER AND STORMS
WILL ACCOMPANY THE FRONT BOTH TONIGHT AND WEDNESDAY. SOME OF THE
STORMS MAY BE ON THE STRONG SIDE WEDNESDAY AFTERNOON SOUTH AND EAST
OF GRAND RAPIDS. HIGHS ON WEDNESDAY WILL PUSH INTO THE UPPER 70S AND
LOWER 80S. THE UPCOMING WEEKEND LOOKS DRY WITH HIGHS IN THE 70S.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 347 PM EDT TUE AUG 6 2013
MAIN CONCERNS IN THE SHORT TERM ARE RELATED TO CONVECTION TONIGHT
AND WEDNESDAY. CURRENT THINKING IS WE WILL SEE SOME SCATTERED
SHOWERS AND STORMS BETWEEN NOW AND MIDNIGHT...WITH BETTER CHANCES
OCCURRING LATE. THE LATEST HRRR GUIDANCE WOULD SUGGEST WE WILL SEE A
THUNDERSTORM COMPLEX ROLL EAST OUT OF WISCONSIN AND MOVE INTO
CENTRAL LOWER MICHIGAN OVERNIGHT. THIS SEEMS PLAUSIBLE GIVEN THE
CONFIGURATION OF THE 850MB LLJ. NOT EXPECTING SEVERE WEATHER AT THIS
TIME...BUT THE SIMULATED REFLECTIVITY IS IN THE FORM OF A SQUALL
LINE.
EXPECT SCATTERED SHOWERS AND STORMS TO BE OVER A DECENT AMOUNT OF
THE FORECAST AREA BETWEEN 09Z AND 15Z AS UPSTREAM RESIDUAL
CONVECTION SLIDES INTO LOWER MICHIGAN OR DEVELOPS OVERHEAD ON THE
LLJ.
SHOWERS AND STORMS SHOULD REFOCUS MIDDAY ALONG THE COLD FRONT THAT
SHOULD BISECT THE CWA. STRONG STORMS ARE POSSIBLE IN THE EASTERN CWA
TOMORROW AFTERNOON WITH 40 KNOTS OF DEEP LAYER SHEAR AND THE
POTENTIAL FOR SOME BREAKS IN THE OVERCAST AHEAD OF THE MORNING
STORMS. CLOUD COVER TOMORROW MORNING WILL DETERMINE THE STRENGTH OF
THE AFTERNOON CONVECTION AS DEEP MOISTURE WILL BE IN PLACE.
THE SHOWERS AND STORMS SHOULD EXIT TO THE EAST EARLY IN THE EVENING
AS THE FRONT SWEEPS THROUGH. MAINLY DRY WEATHER IS THEN FORECAST
FROM WEDNESDAY EVENING THROUGH THURSDAY NIGHT. THERE IS SOME SMALL
POTENTIAL FOR SHOWERS AND STORMS IN THE SOUTH THURSDAY NIGHT...BUT
THIS ACTIVITY MAY JUST MISS THE AREA TO THE SOUTH PER RECENT MODEL
TRENDS.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 347 PM EDT TUE AUG 6 2013
THE POLAR VORTEX OVER EASTERN CANADA WILL CONTINUE TO PLAY A ROLE IN
OUR WEATHER THROUGH THE EXTENDED PERIOD. A STRONG SHORT WAVE MOVING
ACROSS ONTARIO WILL PUSH A COLD FRONT THROUGH THE CWA FRIDAY SENDING
ANOTHER PUSH OF COOLER AIR SOUTH ACROSS THE CWA FOR THE WEEKEND. THE
LACK OF DEEP MOISTURE AND INSTABILITY WILL RESULT IN LIGHT SHOWERS
AT BEST FRIDAY.
MUCH OF THE WEEKEND LOOKS DRY WITH HIGHS IN THE MID 70S AND
DEWPOINTS IN THE 50S AS SFC HIGH PRESSURE SETTLES OVER THE GREAT
LAKES.
ANOTHER SHORT WAVE WILL DROP SOUTH FROM NORTHERN ONTARIO DURING THE
MONDAY/TUESDAY TIME FRAME. SIMILAR TO THE LAST FRONT...THERE WON/T
BE MUCH MOISTURE WITH THIS FRONT EITHER. LOW CHANCES OF SHOWERS WILL
COVER THIS TROUGH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 752 AM EDT TUE AUG 6 2013
NUMEROUS MVFR CIGS AND SCATTERED RAIN SHOWERS THIS MORNING SHOULD
TRANSITION TO PRIMARILY VFR CONDITIONS FOR THIS AFTERNOON INTO
THIS EVENING. MORNING STRATUS DECK WITH BASES OF 1500-2500 FT IS
EXPECTED TO LIFT TO A DIURNAL CUMULUS DECK WITH BASES AROUND 3500
FT THIS AFTERNOON. SOME IFR CIGS ARE POSSIBLE THROUGH MID MORNING
WEST OF HWY 131 INCLUDING MKG.
WHILE THE THUNDER THREAT IS NOT ZERO THIS AFTERNOON AND EVENING...
PROBABLY THE BEST CHANCE OF TSTMS WILL COME LATE TONIGHT AFTER 06Z
ESPECIALLY ALONG AND WEST OF HWY 131.
&&
.MARINE...
ISSUED AT 347 PM EDT TUE AUG 6 2013
HAVE HELD OFF ON ANY SMALL CRAFT ADVISORIES OR BEACH HAZARDS
STATEMENTS AS THE WINDS AND WAVES IN TODAY/S MODEL RUNS ARE NOT AS
SIGNIFICANT AS LAST NIGHT OR YESTERDAY. IT APPEARS AT THIS POINT IN
BOTH THE SOUTHERLY FLOW TONIGHT AND THE NORTH FLOW BEHIND THE FRONT
TOMORROW THAT WE REMAIN BELOW CRITERIA. AM A BIT CONCERNED THOUGH
BASED ON THE WINDS SEEN IN BUFKIT THAT WE WON/T INDEED BE HIGHER
BOTH TONIGHT...WEDNESDAY AND WEDNESDAY NIGHT. WE WILL SEE AS WE
PROGRESS THROUGH THE EVENING AS BUFKIT WOULD SUGGEST INCREASING
WINDS IN THE 04Z-08Z TIME FRAME. WE PLAY THINGS LOWER AT THIS POINT
BUT WATCH CAUTIOUSLY AND CLOSELY.
&&
.HYDROLOGY...
ISSUED AT 347 PM EDT TUE AUG 6 2013
NO SIGNIFICANT HYDRO ISSUES EXPECTED THROUGH THE NEXT COUPLE DAYS
WITH NEAR NORMAL FLOWS IN PLACE NOW AND FORECAST RAINFALL IS NOT
EXPECTED TO BE WIDESPREAD OR OVERLY HEAVY. RAINFALL LAST NIGHT WAS
QUITE LIMITED AS WELL SO WE ARE STARTING OFF WITH FAIRLY DRY GROUND
OVER MUCH OF THE AREA. RAINFALL IS EXPECTED TONIGHT THROUGH
WEDNESDAY...BUT IT WILL BE ASSOCIATED WITH THUNDERSTORM COMPLEXES
THAT WILL BE TRAVERSING THE AREA AT A DECENT CLIP. THE FIRST COMES
LATE TONIGHT AS STORMS THAT FIRE IN MINNESOTA THIS EVENING TRY TO
MOVE ACROSS LAKE MICHIGAN AFTER MIDNIGHT. THESE STORMS WILL LIKELY
AFFECT CENTRAL LOWER MICHIGAN. SCATTERED SHOWERS AND STORMS WILL
THEN TRAVERSE MUCH OF THE AREA LATE TONIGHT AND WEDNESDAY MORNING. A
MORE CONCENTRATED AREA OF SHOWERS AND STORMS WILL AFFECT THE EASTERN
TO SOUTHEASTERN HALF OF THE AREA WEDNESDAY AFTERNOON. WE COULD SEE
GENERAL RAINFALL AMOUNTS ON THE ORDER OF A QUARTER TO HALF INCH WITH
ISOLATED AMOUNTS AROUND AN INCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...93
AVIATION...MEADE
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
324 PM EDT TUE AUG 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 548 AM EDT TUE AUG 6 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN UNUSUALLY DEEP VORTEX
FOR EARLY AUG CENTERED JUST S OF HUDSON BAY ALONG THE
MANITOBA/ONTARIO BORDER. ACROSS THE UPPER LAKES...FLOW HAS BECOME
MORE WESTERLY OVER THE LAST DAY OR TWO IN RESPONSE TO THE
DEEPENING/EXPANDING VORTEX THAT HAS BEEN DRIFTING S. SEVERAL
SHORTWAVES ARE EVIDENT UPSTREAM WITH 2 MORE NOTABLE WAVES OVER ERN
MT/SRN SASKATCHEWAN AND OVER ERN ALBERTA. THESE 2 WAVES WILL POWER A
COLD FRONT ACROSS UPPER MI TONIGHT AND WEDNESDAY MORNING. CLOSER TO
HOME...ISOLD/SCT SHRA (EVEN ISOLD TSRA AT TIMES) HAVE BEEN OCCURRING
OVER THE LAST SEVERAL HRS OVER WRN UPPER MI/ADJACENT LAKE SUPERIOR.
THESE SHRA ARE JUST AHEAD OF A 700MB TROF AND SURGE OF MIDLEVEL
DRYING PER BY LATEST RUC.
FOCUS EARLY THIS MORNING WILL BE ON THE ISOLD/SCT SHRA OVER THE W.
AS AFOREMENTIONED 700MB TROF CONTINUES TO PUSH E...WILL PROBABLY
CONTINUE TO SEE SOME SHRA SPREAD E INTO CNTRL UPPER MI OVER THE NEXT
SEVERAL HRS. LATEST SPC MESOANALYSIS SHOWS MUCAPE AROUND 250J/KG...
SO THERE MIGHT BE AN OCNL LIGHTNING STRIKE THOUGH THERE HAS NOT BEEN
ANY CG STRIKES FOR THE LAST COUPLE OF HRS. AS THE TROF CONTINUES
EASTWARD...IT WILL COINCIDE WITH THE HEATING CYCLE AND SHOULD AID
SHRA/TSRA DEVELOPMENT OVER THE ERN PART OF THE FCST AREA LATE THIS
MORNING/EARLY THIS AFTN...ESPECIALLY INLAND FROM LAKE MICHIGAN. SOME
HIGH RES GUIDANCE (NAM NEST AND RUC13) INDICATE LAKE BREEZE WILL
DEVELOP OFF LAKE SUPERIOR OVER THE E...BUT WILL MAKE LIMITED INLAND
PROGRESS. IF SO...CONVERGENCE ZONE WILL BE A GOOD FOCAL POINT FOR
CONVECTION. TO THE W ACROSS THE W HALF OF UPPER MI...THE SAME HIGH
RES GUIDANCE POINTS TO A MORE ACTIVE INLAND PUSH OF LAKE SUPERIOR
LAKE BREEZE. IN THE FLOW UPSTREAM...THERE ARE PROBABLY SOME SUBTLE
SHORTWAVES PRESENT GIVEN THE SCT CLUSTERS OF SHRA/TSRA THAT WERE
PRESENT EARLIER IN THE NIGHT ACROSS THE NRN PLAINS. WITH EXPECTATION
OF LOW CLOUDS CLEARING OUT/TRANSITIONING TO CU FIELD...DAYTIME
HEATING WILL LIKELY BE SUFFICIENT TO RAISE MLCAPE TO 500J/KG OR SO
PER NAM/GFS. LAKE BREEZE AND ANY SUBTLE SHORTWAVES SHOULD THEN
SUPPORT SCT SHRA/TSRA DEVELOPMENT. WITH DEEP LAYER SHEAR AROUND
35KT...SOME ORGANIZED/STRONGER STORMS ARE POSSIBLE. IF CAPE ENDS UP
HIGHER THAN CURRENTLY EXPECTED...THERE MIGHT BE AN ISOLD SVR STORM
OR TWO.
TONIGHT...THE STRONGER SHORTWAVES WELL UPSTREAM WILL PUSH A COLD
FRONT INTO UPPER MI. AS HAS BEEN THE CASE FOR THE LAST SEVERAL
DAYS...MODELS CONTINUE TO POINT TOWARD A GOOD POTENTIAL OF SHRA/TSRA
SPREADING ACROSS THE FCST AREA. WITH RATHER VIGOROUS DEEP LAYER
FORCING...STRONG MOISTURE TRANSPORT AND SHARP LOW LEVEL TROF
SHIFTING E...WILL RETAIN LIKELY POPS SPREADING E ACROSS THE AREA
TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 548 AM EDT TUE AUG 6 2013
AMPLIFIED UPPER AIR PATTERN PERSISTS THROUGH THE UPCOMING WEEKEND
AND LIKELY INTO NEXT WEEK AS WELL. MEAN TROUGHING DOMINATES MUCH OF
EASTERN CANADA ACROSS THE GREAT LAKES. PRIMARY RESULT OF THIS
PATTERN WILL BE CONTINUATION OF COOLER THAN NORMAL TEMPERATURES
THROUGH AT LEAST MID AUGUST ACROSS UPPER GREAT LAKES REGION. TO
START OUT ON WEDNESDAY...MAIN FEATURES ALOFT ARE CLOSED OFF UPPER
LOW CENTERED ALONG MANITOBA AND NORTHERN ONTARIO BORDER...SHARP WEST
TO EAST RIDGE OVER FAR NORTHERN CANADA AND A DOUBLE BARRELED TROUGH
EXTENDING FROM THE NORTH POLE SOUTHWEST ACROSS ALASKA AND TO THE
NORTHERN PORTIONS OF PACIFIC OCEAN. NOT A WHOLE LOT OF CHANGE WRT
LOCATIONS OF SAID FEATURES THROUGH THE LONG TERM. ONLY THING THAT
DOES CHANGE IS UPPER LOW OVER ONTARIO SLIDES ACROSS QUEBEC THIS
WEEKEND AS STRONGER JET ENERGY BECOMES PLACED OUT AHEAD OF THE
TROUGH...KEEPING IT MORE PROGRESSIVE. MAIN CHANCE OF RAIN IN THIS
PATTERN WILL BE RIGHT OFF THE BAT ON WEDNESDAY MORNING OVER EAST
HALF OF CWA AS COLD FRONT MOVES THROUGH REGION. ADDITIONAL CHANCES
OF RAIN POSSIBLE THURSDAY NIGHT INTO FRIDAY AS SECONDARY LOW PRESSURE
SYSTEM AND COLD FRONT CROSS THE AREA. GENERALLY LOOKS QUIET THROUGH
THE WEEKEND...BUT COOL. NEXT CHANCE OF RAIN PROBABLY ARRIVES LATER
SUNDAY NIGHT INTO MONDAY AS SHORTWAVES DROP ACROSS AREA IN NW FLOW
ALOFT.
COLD FRONT SHOULD BE OVER CNTRL UPR MICHIGAN TO START THE DAY ON
WEDNESDAY...QUICKLY HEADING EAST TO AROUND ERY BTWN 15Z-18Z. NAM
STILL ON THE FAST SIDE...WHILE ECMWF IS SLOWEST. COMPROMISE SOLN
WITH FRONT IS THE GFS/GEM-REGIONAL AS WELL AS NCEP WRF-ARW/NMM.
MAJORITY OF WIDESPREAD SHRA/TSRA WILL BE ALONG AND AHEAD OF FRONT
IN WARM AIR ADVECTION REGIME. GOING FCST LOOKS PRETTY GOOD.
CHANGES TO POPS ON WEDNESDAY WITH FROPA PRETTY MINIMAL. KEPT
LIKELY POPS OVR FAR EAST THROUGH 15Z...THEN TRIMMED BACK QUICKLY
WITH ARRIVAL OF STRONG MID-LEVEL DRYING AND AS PRIMARY H85 MOISTURE
ADVECTION IS EAST OF CWA. SOUNDINGS INDICATE LINGERING LOW-LEVEL
MOISTURE BEHIND COLD FRONT THAT COULD LEAD TO BRIEF PERIOD OF LGT
RAIN/DRIZZLE IN THE MORNING FOR AREAS NEAR LK SUPERIOR.
EVENTUALLY...BLYR BECOMING MIXED ALONG WITH NEGATIVE SFC-H85 THETA-E
ADVECTION WILL SHUT DOWN ANY LINGERING PRECIP BY MIDDAY. HAVE NO
POPS AFTER 18Z WHICH WAS A BIT OF A CHANGE COMPARED TO PREVIOUS
FCST. BKN CU/SC DECK MAY REMAIN LONGER THAN THIS...BUT EVEN THAT
SHOULD TEND TO MIX OUT TO PARTLY CLOUDY SKIES BY MID-LATE AFTN.
TEMPS TRICKY WITH FROPA AS 925-850MB TEMPS JUST AHEAD OF FRONT ARE
PRETTY WARM. FIGURING OUT HOW THE WARM AIR BALANCES BTWN COOLING
FROM CLOUDS/PRECIP IS MAIN HURDLE. WILL GO FOR MAX TEMPS TOPPING OUT
IN THE LOW 70S...WARMEST SOUTH CENTRAL. TEMPS ALONG LK SUPERIOR
COULD RISE EARLY ON...BUT THEN FALL BACK IN THE AFTN WITH INCREASING
ONSHORE FLOW. SHOULD BE ESPECIALLY NOTABLE NEAR MQT-P53. FOG THAT IS
DEVELOPING ACROSS LK SUPERIOR CURRENTLY MAY GET SHOVED ONSHORE TOO
FOR A WHILE.
SFC HIGH RIDGES IN FROM CANADIAN PRAIRIE PROVINCES WEDNESDAY NIGHT
INTO THURSDAY AHEAD OF NEXT COLD FRONT. H85 WINDS STAY ONSHORE ALL
NIGHT...BUT LOWEST LEVEL WINDS THROUGH 900MB BECOME LESS
SO...ALLOWING POTENTIAL FOR TYPICAL COOL SPOTS INLAND FROM THE GREAT
LAKES TO SEE TEMPS FALL INTO THE LOWER 40S. LIGHT GRADIENT WINDS ON
THURSDAY ALLOWS IN LIGHT LAKE BREEZES ALONG BOTH SUPERIOR AND
MICHIGAN. AWAY FM LOCAL COOLING THOUGH...TEMPS SHOULD BOUNCE BACK
INTO AT LEAST THE LOWER 70S MOST AREAS GIVEN H85 TEMPS WARMER THAN
+10C. THICKENING MID CLOUDS /H6-H5/ FOR WEST HALF BY AFTN AS WARM
AIR ADVECTION DEVELOPS AHEAD OF THE COLD FRONT. GFS HAS SHOWED
STEADY TREND IN BACKING OFF QPF INTO WESTERN TIER. USED A BLEND OF
MORE CONSISTENT ECMWF AND THE DRIER TRENDING GFS. RESULT WAS SOME
LOWER CHANCE POPS FOR WESTERN LK SUPERIOR/ISLE ROYALE ON NOSE OF
H85-H7 MOISTURE ADVECTION. AS SFC LOW SPINS OVER NORTHERN ONTARIO
THE COLD FRONT WILL SLOWLY SINK NORTH TO SOUTH ACROSS LK SUPERIOR
ON THURSDAY NIGHT. BEST CHANCE FOR SHRA/ISOLD TSRA WILL BE OVR LK
SUPERIOR DUE TO H85 TEMP ADVECTION/WEAK LOW-LEVEL JET AND SOME
LOW-LEVEL FRONTAL CONVERGENCE. TEMPS WILL BE ON THE MILD SIDE
AGAIN WITH SOUTH WINDS/WARM AIR ADVECTION AHEAD OF FRONT. COLD
FRONT WORKS ACROSS UPR MICHIGAN ON FRIDAY...SO WILL KEEP WITH
SOME LOWER CHANCE POPS. COOLING BEGINS ON FRIDAY...ESPECIALLY NEAR
LK SUPERIOR. INLAND...TEMPS MAY END UP ONLY A COUPLE DEGREES COOLER
THAN THURSDAY.
STRONG DRYING BEHIND FRONT FOR FRIDAY NIGHT AND SATURDAY. JUST SOME
SCT CU SHOULD DEVELOP DURING PEAK HEATING ON SATURDAY. H85 TEMPS
ONLY UP TO +6C WITH STRONGER ONSHORE FLOW WILL LEAD TO A COOL DAY
BY AUGUST STANDARDS WITH READINGS IN THE UPPER 50S/NEAR 60 ALONG LK
SUPERIOR AND MAYBE REACHING 70 DEGREES IN THE FAR SOUTH CENTRAL NEAR
MNM. 60S ELSEWHERE...WHICH IS AT LEAST 10 DEGREES BLO NORMAL.
NOT MUCH IN WAY OF CHANGES TO REST OF CONSENSUS GRIDS FOR EXTENDED.
SLIGHT CHANCE POPS FOR SUNDAY...THOUGH THESE ARE BIASED BY A LATEST
GFS WHICH TRENDED MUCH WETTER FOR PARTS OF CWA COMPARED TO PREVIOUS
RUNS. ECMWF INDICATES SMALL CHANCES OF INSTABILITY SHRA/TSRA AS
ANOTHER STRONGER WAVE OR TWO /CURRENTLY WITHIN THE LARGER TROUGH FM
ALASKA TO THE NORTH POLE/ DROPS ACROSS UPPER LAKES. POCKET OF STEEPER
MID-LEVEL LAPSE RATES WOULD JUSTIFY AT LEAST A MENTION OF TSRA DURING
PEAK HEATING OF SUNDAY AFTN LINGERING INTO SUN EVENING. SIMILAR SETUP
FOR MONDAY THOUGH BY THAT TIME BETTER FORCING IS SLIDING EAST AND
SOUTH OF LK SUPERIOR REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1151 AM EDT TUE AUG 6 2013
SLIGHTLY DRIER AIR ACROSS NE MN THIS MORNING HAS HAD A DIFFICULT
TIME MOVING INTO UPPER MI. EVEN WITH ABUNDANT LOW LEVEL
MOISTURE...AND AN ADDITIONAL PUSH OUT OF WI ON S-SW WINDS...CEILINGS
HAVE BEEN ABLE TO SLOWLY RISE INTO MVFR CATEGORY THANKS IN PART TO
BETTER MIXING /DAYTIME HEATING/. VFR CONDITIONS WILL BE POSSIBLE
THIS AFTERNOON AHEAD OF A COLD FRONT NEARING FROM MN...WITH
DETERIORATING CONDITIONS AGAIN BY THE MID-LATE EVENING HOURS. THERE
IS A POTENTIAL FOR A BROKEN LINE OF POP UP SHOWERS AND THUNDERSTORMS
OVER MAINLY CENTRAL AND E UPPER MI THIS AFTERNOON. WILL KEEP MENTION
OF VCSH AT SAW...WITH THE POTENTIAL OF ADDING TS/CB IF ANYTHING
LOOKS MORE CERTAIN. COLD FRONT WILL MOVE INTO UPPER MI
TONIGHT...BRINGING A PERIOD OF SHRA/TS AND A RETURN TO MVFR AND
POSSIBLY IFR CONDITIONS. ONCE FRONT PASSES...UPSLOPE FLOW AT
KIWD/KCMX AND TO A LESSER EXTENT SAW WILL RESULT IN LIFR CONDITIONS
WHICH WILL LINGER THROUGH THE MID MORNING HOURS BEFORE QUICKLY
CLEARING DURING THE MID-LATE MORNING HOURS W TO E.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 323 PM EDT TUE AUG 6 2013
WIND GUSTS SHOULD REMAIN AT OR BELOW 25KTS...WITH THE STRONGEST
GUSTS OUT OF THE W TO NW EXPECTED LATE TONIGHT THROUGH WEDNESDAY
CENTRAL AND EAST...AND AGAIN FRIDAY AFTERNOON AND EVENING BEHIND A
COUPLE OF COLD FRONT SWINGING ACROSS LAKE SUPERIOR. LOW PRESSURE
ACROSS WESTERN LAKE SUPERIOR WILL CONTINUE ACROSS LAKE SUPERIOR
THROUGH WEDNESDAY MORNING. PATCHY TO AREAS OF FOG SHOULD DIMINISH IN
COVERAGE DURING THE DAY WEDNESDAY AS DRIER AIR SLIDES OVERHEAD.
EXPECT HIGH PRESSURE TO BUILD EAST INTO THE UPPER GREAT LAKES BY
THURSDAY MORNING. AS THE HIGH SHIFTS EAST...A TROUGH WILL MOVE
ACROSS LAKE SUPERIOR THURSDAY NIGHT THROUGH FRIDAY MORNING. HIGH
PRESSURE WILL THEN BUILD SOUTHEAST INTO THE UPPER MISSISSIPPI VALLEY
SATURDAY...AND LINGER ACROSS THE REGION THROUGH SUNDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...KF
MARINE...KF
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
204 PM CDT Tue Aug 6 2013
.SHORT TERM...(Today and Tonight)
ISSUED AT 349 AM CDT TUE AUG 6 2013
Very serious flooding situation unfolding across the area this
morning. A band of thunderstorms producing heavy rainfall has set
of up from roughly the Lake of the Ozark area southeastward
through portions of Laclede/Pulaski counties and into the northern
half of Texas county. Radar estimates vary a bit, but given
rainfall rate observations from the past several nights, as much
as 8" of rain has fallen in spots.
This band of rainfall will be the primary concern this morning. A
decaying line of storms entering from the west has produced a
large swath of moderate rain. Rainfall amounts are more modest
with a general half inch to one inch of rainfall over a longer
duration, with embedded pockets of up to two inches of rainfall.
The biggest concern for this morning is that band of torrential
rainfall from central Missouri into the eastern Ozarks and the
extreme flooding risk. Looking at the HRRR and other short range
models, this band of rainfall will not move much through day
break. With hourly rainfall rates between one and two inches, a
bad situation will only get worse.
Rain will gradually end from west to east during the mid to late
morning hours. Like yesterday some clearing is expected and a warm
and humid afternoon is in store. Instability will quickly increase
during the afternoon and additional isolated to widely scattered
thunderstorms will be possible across the entire area. There will
be a limited risk for severe with this activity, with hail to the
size of quarters and localized damaging wind gusts. This activity
will likely persist into the evening in a widely scattered
fashion. Then attention will turn to a complex of thunderstorms
develop to our north/northwest. This will approach the area from
the northwest overnight tonight. In addition, much like the past
few nights, will need to watch for low level jet interaction with
any lingering boundaries. This activity will be possible just
about anywhere across the outlook area. The air mass remains
extremely moist, and flash flooding will once again be a major
concern.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 349 AM CDT TUE AUG 6 2013
The forecast for midweek into early next week remains complex and
concerning. Northwest flow aloft will keep our region in the
atmospheric battleground, and multiple rounds of showers and
thunderstorms remain possible. There is moderate confidence in
another round of heavy rainfall Wednesday night into Thursday. As
a result, the Flash Flood Watch will be extended into Thursday
morning.
The medium range models do offer a glimmer of hope for the weekend
and the pattern briefly deamplifies and the atmospheric
battleground shifts just to the west. Tough to get to confident in
this solution given the persistent upper level pattern that has
been in place. One can certainly hope, though.
The bottom line is that more rounds of rain will be possible.
Temperatures will be at or below average (depending on cloud
coverage and rain).
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
ISSUED AT 156 PM CDT TUE AUG 6 2013
For the KSGF/KJLN/KBBG tafs...a front over IA/NEB will drop south
into the region tonight. Scattered showers are ongoing near KJLN
and KSGF and will watch trends, but better chances for showers and
thunderstorms would appear to be tonight toward 06Z. Will keep
tafs mainly in the vfr cat but no doubt there will be mvfr or ifr
possibilities in heavier rain showers. There is potential for a
more prolonged period of lower clouds late in the taf period near
and just north of the sfc boundary, but there is not a lot of
confidence in the boundary position by that time.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH through Thursday morning FOR MOZ055>058-
066>071-077>083-088>098-101>106.
KS...FLASH FLOOD WATCH through Thursday morning FOR KSZ073-097-101.
&&
$$
SHORT TERM...Gagan
LONG TERM...Gagan
AVIATION...DSA
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1221 PM CDT Tue Aug 6 2013
.SHORT TERM...(Today through Wednesday)
Issued at 307 AM CDT TUE AUG 6 2013
Large MCS continues to interact with synoptic boundary arcing from
west central Missouri southeast through the Ozarks. Based on 00Z
soundings, convective outflow boundary should be more than sufficient
forcing to easily overturn the entire warm sector air mass as well as
the region through about 50 miles north. This sharp delineation has
been well handled by the HRRR and NSSL WRF runs, and takes the
northern extent of the thunderstorms to roughly the MO river from
Kansas City metro eastward. Thunderstorm cloud tops have continued
to be in the -75 to -80C range with prolific lightning counts. This
would suggest that despite the rich boundary layer moisture, rainfall
efficiency is not as high as it could be. Nonetheless, 1-2"/hr rates
are almost certain in the heavier cells, and there may be some
tendency for slower storm movement/propagation where the outflow
boundary becomes W-E oriented along the nrn edge of the convection.
80-100% POPs generally carried along and south of the MO river
(slightly more NW- SE oriented) with a rapid decrease further north.
Given the short term setup, while we definitely need the rain around
Kansas City, mesoscale influences suggest this is also the most
likely region for flooding through the next 3-4 hours if conceptual
evolution materializes.
Elsewhere, areas of light fog are expected along the periphery of the
MCS cloud shield where subsidence will work in concert with more
efficient boundary layer cooling and high antecedent moisture
content.
MCS (if not MCC designated) should gradually exit the CWA to the
southeast this morning as the low level jet veers, with convective
debris cirrus lingering through the morning. Like yesterday, most
aggressive warming will occur during the afternoon hours. Given the
very stagnant air mass in place, will introduce haze into the
forecast, coupling with otherwise very sultry conditions expected as
dewpoints climb into the middle 70s. Other than a rogue pulse
thunderstorm or two during the afternoon along a residual boundary,
expect the region to be fairly quiet between 15-00Z.
By evening, a disturbance currently producing active deep convection
over SW South Dakota will reach far NW MO. Despite model variances,
there appears to be an overall suggestion that at least scattered
thunderstorms will develop and/or move into NW MO early this evening,
possibly growing upscale overnight as this activity moves southeast.
SPC highlights the area with a broad slight risk overnight for wind
damage potential. Given some modest increase/linearity to the
700-500mb flow, certainly cannot rule out some storm organization.
This system should also clear the region by late morning, leaving a
hazy, warm and very humid day again on Wednesday.
.LONG TERM...(Thursday through Monday)
Issued at 307 AM CDT TUE AUG 6 2013
Remnant energy lifting northward out of the Baja California
Peninsula and into the Central Plains on Thursday will provide a
reasonable chance for fairly widespread rains across the lower
Missouri river valley. By Thursday morning ECMWF/GFS both suggest
increased troughing over the central Rockies, allowing for southwest
flow to move into the Plains. Strong warm advection ahead of this
wave of energy may be strong enough to force baroclinic zone which
has been stuck to the south of the CWA northward during the day. As
this upper wave ejects eastward Thursday night into Friday, fairly
pronounced mid-level lift provided by PVA and an enhanced upper jet
streak should keep PoPs high overnight as several rounds of showers
and thunderstorms will be possible.
High pressure is expected to sink southward into the central US on
Friday, leading to dry conditions for the first half of the weekend.
Increased troughing off the West Coast combined with fairly
progressive zonal flow over the Nation`s midsection will lead to
lower forecast confidence by early next week. Several waves of
energy may again eject eastward out of this trough, but timing of
these features remains too problematic to target any one time period
for higher PoPs.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1216 PM CDT TUE AUG 6 2013
Challenging precipitation forecast for the next 24 hours. Cannot
rule out a brief shower this afternoon at terminals, but with no
expected reduction in flight category have left out of TAF at this
time. Otherwise anticipate overnight showers/thunderstorms in the
vicinity or over terminals during the 05-13Z window, but specific
impacts and timing still highly uncertain. Wind shift expected
Wednesday morning following a cold frontal passage to prevailing
northeasterly winds.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Bookbinder
LONG TERM...Dux
AVIATION...Blair
AREA FORECAST DISCUSSION
NWS GLASGOW MT
215 PM MDT TUE AUG 6 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
NORTHWESTERLY FLOW ALOFT CONTINUES THROUGH THURSDAY. WEATHER FOR
THE NORTHERN CONUS IS DOMINATED BY A LARGE UPPER LOW OVER NORTH
CENTRAL CANADA. AS THIS LOW SPINS AND MAKES SLOW PROGRESS
EASTWARD OVER THE NEXT FEW DAYS...PERIODIC SHORTWAVE DISTURBANCES IN
THE FLOW AROUND THE LOW PASS OVER THE MONTANA AREA. THESE
DISTURBANCES BRING SUPPORT FOR SHOWERS AND THUNDERSTORMS. SHOWER
ACTIVITY MOSTLY OCCURS IN THE AFTERNOONS AS DAYTIME HEATING OF THE
RELATIVELY MOIST BOUNDARY LAYER CREATES CONVECTIVE INSTABILITY
WHICH COMBINES WITH MODEST UPPER LEVEL FORCING FROM SHORTWAVE
ACTIVITY.
CURRENTLY..SOME NON-SEVERE SHOWER AND THUNDERSTORM ACTIVITY IS
EXPECTED WITH THE PASSAGE OF A SHORTWAVE TONIGHT WITH A WEAKER ONE DUE
LATE WEDNESDAY. THURSDAY AFTERNOON HAS A LOWER CHANCE OF
CONVECTIVE ACTIVITY AS THE GFS AND NAM HAVE THE CANADA LOW BY
THAT TIME FAR ENOUGH EASTWARD TO ALLOW SOME BUILDING OF HIGH
PRESSURE OVER THE ROCKIES.
FOR TONIGHT...THE HRRR MODEL SEEMS TO HAVE A REASONABLE HANDLE ON
DEVELOPMENT FOLLOWING THE LOWER RESOLUTION MODELS IN PRODUCING AN
AREA OF SHOWERS OVER THE NORTHEAST 2/3RDS OF THE CWA...WHICH DIES OUT
AROUND 9PM. STRENGTH OF CONVECTION IS EXPECTED TO BE
MODEST...THOUGH SOME THUNDERSTORMS WILL OCCUR...AS BOUNDARY LAYER
INSTABILITY IS WEAK WITH LESS THAN 1000 J/KG OF MLCAPE AT
MOST...WHICH RAPIDLY DECLINES AFTER 6PM AS THE SURFACE COOLS
DIURNALLY.
TEMPERATURES ARE EXPECTED TO BE MILD THROUGH THURSDAY DUE TO CLOUD
COVER AND LIMITED THICKNESSES IN THE SOUTHWEST QUADRANT OF THE
CANADA LOW. THERE IS ALSO A LACK OF WELL-DEFINED SURFACE FEATURES
THAT WOULD LEAD TO STRONG WINDS. CURRENT SURFACE LOW EXITING THE
DAKOTAS HAS KEPT NORTHWESTERLY SURFACE WINDS IN PLACE. THESE WINDS
WILL BECOME LIGHTER TONIGHT AND WEDNESDAY...AND THEN MORE EASTERLY
ON THURSDAY AS A THERMAL SURFACE LOW DEVELOPS OVER THE ROCKIES. MARTIN
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE EXTENDED PERIOD BEGINS THURSDAY NIGHT WITH HIGH PRESSURE AND A
HEAT DOME OVER THE SOUTHWESTERN DESERT...WITH AN UPPER RIDGE
EXTENDING NORTH ALL THE WAY UP INTO THE PACIFIC NORTHWEST. THE
CLOSED UPPER LEVEL CANADIAN LOW WILL BE RETREATING EAST INTO
ONTARIO...LEAVING BEHIND IN ITS WAKE ANOTHER...BUT WEAKER...TROUGH
OVER THE PRAIRIE PROVINCES. THIS PATTERN WILL MAINTAIN OUR
NORTHWEST FLOW ALOFT AND THE STATIONARY BOUNDARY ACROSS NORTHEAST
MONTANA THROUGH MOST OF THE WEEKEND. THIS FLOW WILL NOT BE
CLEAN...RESULTING IN OCCASIONAL SHORT PERIODS OF RAIN SHOWERS OR
THUNDERSTORMS. THEN AS THE RIDGE ATTEMPTS TO MOVE EAST A COUPLE OF
LOWS IN THE PAC-NW AND WESTERN CANADA SEND MOISTURE OVER THE
DIVIDE. THIS MOISTURE AND MORE DISTURBANCES WILL TEND TO KNOCK
DOWN THE RIDGE AND CONTINUE TO PRODUCE RAIN SHOWERS AND
THUNDERSTORMS INTO NEXT WEEK. GUIDANCE SUGGEST WARMING TO ABOVE
NORMAL...BUT THE PATTERN MIGHT RESIST THAT GUIDANCE TREND. FEW
SIGNIFICANT CHANGES WERE NEEDED. SCT
PREVIOUS DISCUSSION...
FORECAST THROUGH THE END OF THE WEEK WILL BE INFLUENCED BY THE
LINGERING EFFECTS OF THE STRONG HUDSON BAY LOW. UPPER RIDGE
BUILDING NORTH ALONG THE ROCKIES WILL BE THE MAIN PLAYER FOR EARLY
NEXT WEEK.
MODELS SLIPPING OUT OF AGREEMENT REGARDING THE HUDSON BAY LOW
AFTER IT DROPS INTO CENTRAL MANITOBA. ECMWF MOVES IT EAST FASTER
THEN THE GFS BUT LEAVES A PORTION BEHIND IN SASKATCHEWAN THURSDAY
NIGHT. EC CURRENTLY NOT INDICATING MUCH INFLUENCE ON THE SENSIBLE
WEATHER WITH THIS FEATURE BUT THAT COULD CHANGE. NORTHWEST FLOW
INTO EASTERN MONTANA ALONG WITH CANADIAN HIGH PUSHING INTO THE
NORTHERN PLAINS SUGGEST A SHORT PERIOD OF DRIER WEATHER BUT AS
SHORTWAVES BEGIN EJECTING OUT OF THE TROF ALONG THE WEST COAST AND
THROUGH THE NORTHERN ROCKIES RIDGE...WILL SEE A RETURN OF
THUNDERSTORM CHANCES.
AFTER A COOL START TO THE EXTENDED PERIOD WITH THE PROXIMITY OF
THE HUDSON BAY LOW...TEMPERATURES WILL WARM THROUGH THE WEEKEND
AS UPPER RIDGE PUSHES OUT INTO THE NORTHERN PLAINS. EBERT
&&
.AVIATION...
VFR.
AN UPPER LEVEL RIDGE WEST OF THE DIVIDE AND A STRONG LOW PRESSURE
SYSTEM OVER HUDSON BAY WILL MAINTAIN NORTHWEST FLOW ALOFT FOR
NORTHEAST MONTANA. THESE WEATHER SYSTEMS HAVE PLACED A STATIONARY
COLD FRONT ACROSS THE LOCAL AREA THAT WILL BE THE FOCUS OF
INTERMITTENT RAIN SHOWERS AND GENERAL THUNDERSTORMS THIS AFTERNOON
THROUGH WEDNESDAY. BRIEF PERIODS OF LESS THAN VFR CONDITIONS ARE
POSSIBLE WITH ANY THUNDERSTORM THAT DEVELOPS.
A SURFACE TROUGH ACROSS THE DAKOTAS WILL MAINTAIN NORTHERLY SURFACE
WIND THIS AFTERNOON. EXPECT WIND SPEED OF AROUND 10KT TO 20KT.
WIND WILL BECOME LIGHT AND VARIABLE TONIGHT AND INTO WEDNESDAY
AFTERNOON. SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
122 PM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE MID-ATLANTIC COAST WILL MOVE FARTHER OUT TO
SEA THIS WEEK...BUT A RIDGE AXIS WILL REMAIN ACROSS NORTH CAROLINA
THROUGH WEDNESDAY. AS WINDS GRADUALLY TURN MORE SOUTHERLY HEAT AND
HUMIDITY WILL RETURN LATE IN THE WEEK. A PIEDMONT TROUGH WILL
DEVELOP INLAND FRIDAY AND SATURDAY AHEAD OF A COLD FRONT THAT MAY
APPROACH FROM THE NORTH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM TUESDAY...ANOTHER COOL DAY ON TAP ACROSS THE EASTERN
CAROLINAS AS CANADIAN HIGH PRESSURE DRIFTING OFFSHORE THE
MID-ATLANTIC CONTINUES ITS INFLUENCE OVER THE REGION. AN UPPER LEVEL
IMPULSE MOVING THROUGH THE EASTERN CONUS LONGWAVE TROUGH MAY BRING
SOME LIGHT RAIN SHOWERS TO THE AREA LATER THIS MORNING INTO THE AFTN.
WEAKENING COLD FRONT HAS CRUISED TO JUST SOUTH OF THE
FLORIDA-GEORGIA LINE...WITH CANADIAN HIGH PRESSURE KEEPING THE HEAT
OF THE SUMMER AT BAY. TEMPS TODAY WILL STRUGGLE AGAIN TO SEVERAL
DEGREES BELOW NORMAL FOR EARLY AUGUST...REACHING ONLY THE LOW 80S
ACROSS THE NORTHERN TIER...MID/UPR 80S FAR SOUTH. WHILE WINDS WILL
SLOWLY BECOME MORE S/SE TODAY AS HIGH PRESSURE RETREATS FURTHER
OFFSHORE...THIS CONTINUES TO ADVECT VERY DRY AIR INTO THE CWA SINCE
STREAMLINES SUGGEST CANADIAN AIR-MASS ORIGIN, AS NOTED BY PREVIOUS
FORECASTER. THIS CONTINUED DRY AIR IS IMPORTANT TO NOTE...SINCE IT
WILL HAVE CONSIDERABLE IMPACT ON PRECIP CHANCES THROUGH THIS EVE.
AN UPPER IMPULSE NOTED ON WV IMAGERY IS PRODUCING AN AREA OF LIGHT
TO MDT RAIN SHOWERS...CURRENTLY JUST WEST OF THE ILM CWA. THIS
SHORTWAVE WILL MOVE NEARLY OVERHEAD THIS AFTN...EXITING OFFSHORE BY
4PM THIS EVE. FORECAST PROFILES SUGGEST INCREASING MID-LEVEL
SATURATION FROM ELIZABETHTOWN...TO FLORENCE...AND POINTS WEST THIS
AFTN...WHILE THE COASTAL REGION REMAINS QUITE DRY. THIS POINTS TO
THE POTENTIAL FOR A PERIOD OF SHOWERS...FOCUSED MAINLY ACROSS THE
WESTERN HALF OF THE CWA...WITH PRECIP ERODING SLOWLY AS THE
SHORTWAVE TRAVERSES EASTWARD. THIS IS ALREADY EVIDENT ON
REFLECTIVITY...SO INHERITED LOW-CHC ACROSS THE NW TIER REMAINS
UNCHANGED...BUT DID EXPAND SCHC POP SE SLIGHTLY TO ACCOUNT FOR
LATEST HRRR WHICH HAS PERFORMED WELL THIS MORNING. EVEN PLACES THAT
DO NOT RECEIVE RAINFALL TODAY WILL SEE INCREASING MID LEVEL
CLOUDINESS.
TONIGHT...RENEWED DRYING WILL OCCUR WITHIN THE COLUMN...BRINGING AN
END TO ANY PRECIP CHANCES FOR THE PERIOD. LIGHT SOUTHERLY WINDS WILL
PERSIST HOWEVER...SO EVEN AS SKY CONDITIONS IMPROVE...RADIATIONAL
COOLING WILL BE SOMEWHAT INHIBITED. MINS WILL BE A DEGREE OR TWO
WARMER THAN LAST NIGHT...FALLING TO 70-73 AT THE COAST...67-70
INLAND.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...HIGH PRESSURE WILL SHIFT FARTHER OFF THE
EAST COAST THROUGH THE PERIOD. COASTAL CAROLINAS WILL BASICALLY BE
IN A DEEPER WARMER AND MOISTER RETURN FLOW ON THE WESTERN
PERIPHERY OF THE ATLANTIC RIDGE BY THE END OF THE PERIOD. THE FLOW
WILL SHIFT FROM SE ON WED TO S-SW BY FRI MORNING. ALTHOUGH
DEWPOINT TEMPS WILL BE CREEPING BACK UP TOWARD 70 ON WED...THE
ATMOSPHERIC COLUMN WILL REMAIN RELATIVELY DRY WITH PCP WATER
VALUES AROUND 1.5 INCHES. LOOKS LIKE A MINOR PERTURBATION FROM THE
WEST IN THE MID LEVEL FLOW WILL REACH THE COAST OVERNIGHT WED AND
MAY SEE SOME CLOUDS AND AN ISOLATED SHOWER OR TWO MOVING ACROSS
THE COASTAL WATERS AND POSSIBLY JUST ALONG THE COAST.
OTHERWISE...EXPECT PLENTY OF SUNSHINE FOR WED. BY THURS A DEEPER
SOUTHERLY FLOW WILL CONTINUE TO FEED MOISTURE INTO THE AREA
BRINGING PCP WATER VALUES UP TO 1.75 INCHES...BUT MID TO UPPER
RIDGE WILL NUDGE INTO THE AREA FROM THE EAST. OVERALL EXPECT CU
BUILDUP IN THE AFTERNOON AND ONLY LOCALIZED CONVECTION MAINLY
ALONG THE SEA BREEZE BOUNDARY WITH DRY AIR AND SUBSIDENCE ALOFT TO
PREVENT MORE WIDESPREAD ACTIVITY. TEMPS WILL RUN SLIGHTLY BELOW
NORMAL ON WED WITH MID 80S MOST PLACES AND WILL HEAD BACK TO
NORMAL ON THURS WITH READINGS NEAR 70 FOR LOWS AND CLOSER TO 90
FOR HIGHS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...SOUTHERLY RETURN FLOW WILL PERSIST AROUND
ATLANTIC HIGH PRESSURE AS MID TO UPPER RIDGE BUILDS OVER THE AREA
FROM THE SOUTHEAST FRI INTO SAT. THE SOUTHERN EXTENT OF A COLD
FRONT WILL REACH THE CAROLINAS BY SATURDAY BUT WILL END UP
STALLING WITH PIEDMONT TROUGH INLAND AND SEA BREEZE BOUNDARY BEING
THE MAIN FEATURES TO FOCUS ANY CONVECTION ON BOTH FRI AND
SATURDAY. THE H5 RIDGE UP TO 595 DEM JUST OFF THE COAST FRI INTO
EARLY SAT SHOULD PROVIDE ENOUGH SUBSIDENCE TO KEEP SHOWER ACTIVITY
LIMITED TO MAINLY INLAND AREAS. BY SATURDAY THE RIDGE GETS
SUPPRESSED FARTHER SOUTH AS MID TO UPPER TROUGH BEGINS TO DIG DOWN
THE EAST COAST WITH SFC TROUGH/FRONT SHIFTING SOUTHEAST AND CLOSER
TO THE COAST. BY LATE SUNDAY THROUGH TUESDAY...A MUCH DEEPER
COLUMN OF MOISTURE WILL BE PRESENT WITH PCP WATER VALUES UP ABOVE
2 INCHES. OVERALL EXPECT INCREASING CHC OF MORE WIDESPREAD
CONVECTION INTO EARLY NEXT WEEK WITH GREATER INSTABILITY AND
MOISTURE IN THE ATMOSPHERE AS DECENT UPPER LEVEL SUPPORT.
DEWPOINT TEMPS WILL BE BACK UP IN THE 70S WITH OVERNIGHT LOWS
IN THE MID 70S AND DAY TIME HIGHS REACHING INTO THE 90S. CLOUDS
AND PCP MAY KEEP VALUES SLIGHTLY LOWER EACH AFTERNOON INTO EARLY
NEXT WEEK.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 18Z...STRATIFORM PRECIP LOOKS TO HANG IN THERE THROUGH MUCH OF
THE AFTERNOON...AFFECTING MAINLY FLO AND LBT. VISIBILITIES WILL
REMAIN VFR AS WELL AS CEILINGS IN THE PRECIP. MAINLY A MID CLOUD
CEILING THROUGHOUT THE REGION THROUGH THE AFTERNOON HOURS WITH A
VARIABLE WIND...STRONGEST...AND FROM THE SOUTHEAST...NEAR THE COAST.
MUCH OF THE CLOUDS DISSIPATE THROUGH THE OVERNIGHT HOURS. SOME MVFR
FOG IS POSSIBLE AT THE INLAND TERMINALS AS THE PRECIP THIS AFTERNOON
SHOULD MOISTEN UP THE LOWER LAYERS JUST ENOUGH. WEDNESDAY...BECOMING
VFR WITH MAINLY SCATTERED SKIES AND A CONTINUED SOUTHEAST
WIND...MAINLY LESS THAN 10 KTS.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE WEDNESDAY THROUGH SUNDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 1015 AM TUESDAY...CANADIAN HIGH PRESSURE JUST OFF THE
MID-ATLANTIC COAST WILL CONTINUE TO PUSH SLOWLY AWAY FROM SHORE
THROUGH TONIGHT. WHILE THIS OCCURS...A RIDGE AXIS WILL CONTINUE TO
EXTEND BACK TOWARDS THE EASTERN CAROLINAS...KEEPING THE PRESSURE
GRADIENT LIGHT AND WINDS E/SE AT AROUND 10 KTS. SEAS AT THE LOCAL
BUOYS ARE CURRENTLY ALL 2 FT OR LESS...AND THIS WILL PERSIST THROUGH
THE PERIOD WITH LITTLE CHANGE. WAVES WILL BE FORMED BY A CONTINUED
4-SEC E/SE WIND CHOP AND 10 SEC SE GROUND SWELL.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...RETURN FLOW AROUND ATLANTIC RIDGE OF HIGH
PRESSURE WILL PERSIST THROUGH THE PERIOD. THE FLOW WILL VEER
AROUND FROM SOUTHEAST ON WED BECOMING MORE S-SW ON THURS. THE
WINDS WILL REMAIN AROUND 10 KTS SPIKING UP A BIT EACH AFTERNOON IN
THE SEA BREEZE. THE PERSISTENT ON SHORE PUSH WILL KEEP SEAS AROUND
2 TO 3 FT WITH SHORTER PERIOD WIND WAVES MIXING WITH A LONGER
PERIOD 9 SECOND SE SWELL.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...EXPECT A SOUTH TO SOUTHWEST FLOW TO
CONTINUE THROUGH THE PERIOD AROUND ATLANTIC HIGH. THE WINDS WILL
VEER SLIGHTLY MORE INTO THE WEEKEND AS PIEDMONT TROUGH BECOMES
MORE PRONOUNCED AND COLD FRONT MOVES INTO THE CAROLINAS FROM THE
NORTHWEST OVER THE WEEKEND. THE GRADIENT WILL TIGHTEN BETWEEN INLAND
TROUGH/FRONT AND HIGH PRESSURE OFF SHORE TO PRODUCE WIND 10 TO 15 KTS
THROUGH THE PERIOD. THE INCREASED SOUTHERLY PUSH WILL PRODUCE A
RISE IN SEAS UP CLOSER TO 3 FT THROUGH THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...43/17
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
101 PM EDT TUE AUG 6 2013
.SYNOPSIS...
INSTABILITY INCREASES LATE TODAY AND OVERNIGHT. STRONGER MID LEVEL
DISTURBANCE PASSES WEDNESDAY. MORE ROUNDS OF CONVECTION INTO THIS
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
ONCE YOU GET SPOILED BY THOSE RARE LOWER DEW POINTS IN THE DOG DAYS
OF SUMMER...YOU HATE TO SEE THEM LEAVE. THE INITIAL MID LEVEL
DISTURBANCE WAS CROSSING THE CENTRAL WV MOUNTAINS THIS EARLY HOUR OF
08Z. A SECONDARY 500 MB VORT IS INDICATED ON THE 07Z RAP MODEL
PASSING N OF BKW AROUND 09-10Z.
MEANWHILE...WHILE THE MID LEVEL MOISTURE INCREASED FROM THE WEST
LAST NIGHT...THE LOWER LEVEL MOISTURE MADE ITS FASTEST INITIAL
CHARGE NORTH...ON THE EASTERN SLOPES OF THE APPALACHIANS. YET...THE
925 TO 850 MB FLOW REMAINS WEAK AND STARTS VEERING MORE TOWARD SOUTH
AND SOUTHWEST. SO TOUGH CLOUD FORECAST TODAY FOR AREAS FROM BKW EAST
INTO THE UPPER GREENBRIER VALLEY.
MEANWHILE...IN THE WAKE OF THE MID LEVEL DISTURBANCE...BREAKS IN THE
CLOUDS COULD YIELD SOME BRIEF FOG IN THE MID OHIO VALLEY FOR DAWN.
NO MAJOR CHANGES TODAY...KEPT A 20/30 POPS OVER THE MOUNTAINS FOR
THE AFTERNOON HEATING IN THE WEAK FLOW. ALSO KEPT THE POSSIBILITY
OF CONVECTION FORMING FOR OUR NE KENTUCKY AND THE TRI STATE AROUND
HTS AFTER 18Z.
MOST MODELS LIKE THE ECMWF...GFS HOLD US DRY OVERNIGHT. BUT NAM
SHOWS MINOR FEATURES WITH INCREASING LOW LEVEL WINDS/FORCING AT
925 MB TO 850 MBS. IT IS TOO PREMATURE TO REMOVE POPS IN OUR
SOUTHERN AND WESTERN COUNTIES FOR TONIGHT. I DID TRY TO HOLD THE
ROUTE 50 CORRIDOR INCLUDING PKB TO CKB DRY MOST OF THE NIGHT. HAVE
POPS INCREASING INTO THE 30 TO 40 PERCENT RANGE ACROSS THE SOUTH
OVERNIGHT. CERTAINLY THE LONGER WE CAN HOLD OFF AREAS OF HEAVIER
CONVECTION THE BETTER...CONSIDERING THE ACTIVE PATTERN INTO THIS
WEEKEND.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
NEW 00Z MODELS LEAVE SOME QUESTION TO HOW THINGS WILL PLAY OUT
THROUGH THE SHORT TERM...AS ECMWF HAS MOVED BEST UPPER LEVEL SUPPORT
FARTHER NORTH WHILE NAM/GFS HAVE BEEN FAIRLY CONSISTENT WITH
PREVIOUS RUNS LOCATION WISE. ALL MODELS HAVE SLOWED DOWN A BIT WITH
THE PRECIP FOR WEDNESDAY...SO TRENDED THAT WAY. DESPITE THE MODEL
DIFFERENCES...THUNDERSTORMS LIKELY WEDNESDAY INTO WEDNESDAY NIGHT
AND WITH PW VALUES CLIMBING ABOVE 2 INCHES HEAVY RAIN IS ALSO
LIKELY. TRAIN OF VORT MAXES CONTINUES AS COLD FRONT APPROACHES
THURSDAY THROUGH FRIDAY. GFS STILL SHOWS THE COLD FRONT TRYING TO
PUSH THROUGH FRIDAY NIGHT...HOWEVER NEW ECMWF STALLS THE SURFACE
FRONT NEAR TO JUST NORTH OF CWA. THINK THE ECMWF MAY BE ON TO
SOMETHING...BUT WITH THIS BEING THE FIRST INDICATION...WON/T JUMP
FULLY ON IT YET. DID INCREASE LOWS FRIDAY NIGHT QUITE A BIT...WITH
ONLY MINIMAL CHANGES MADE TO OTHER TEMPS.
WILL CONTINUE WATER CONCERN MENTION IN HWO. THINK MOST LOCATIONS
SHOULD BE ABLE TO HANDLE WEDNESDAYS BATCH OF HEAVY RAIN SINCE WE
HAVE HAD SOME TIME TO DRY OUT SINCE LAST SIGNIFICANT RAIN...SO AM
MORE CONCERNED WITH REPETITIVE STORMS ADDING UP THROUGH THE END OF
THE WEEK. WITH THAT SAID...CAN NOT RULE OUT LOCALIZED ISSUES
WEDNESDAY DUE TO DOWNPOURS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
GENERALLY USED WPC THINKING FOR THIS PORTION OF THE FORECAST.
HOWEVER...HAVE MADE SOME CHANGES TO REFLECT DIFFERENCES IN LATEST
MODEL GUIDANCE.
WPC INDICATES A COLD FRONT SHOULD BE LOCATED JUST TO OUR NORTHWEST
EARLY IN THE PERIOD. THE COLD FRONT WILL PUSH SOUTHEAST SATURDAY AND
SATURDAY NIGHT. SEVERAL MID-LEVEL SHORTWAVES AND A WEAK AREA OF LOW
PRESSURE WILL THEN PUSH EAST MONDAY INTO TUESDAY.
LATEST GFS IS SLOWER WITH THE SOUTHEAST PROGRESS OF THE COLD
FRONT. WITH THIS IN MIND...HAVE HELD ONTO LOW POPS A LITTLE LONGER
FOR SATURDAY NIGHT INTO SUNDAY.
LOWERED HPC TEMP NUMBERS A FEW DEGREES AS THEY APPEAR TOO WARM FOR
THE EXPECTED CONDITIONS.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THE MID LEVEL DISTURBANCE CROSSING THE WV MOUNTAINS BETWEEN EKN AND
BKW AT 10Z. WITH BREAKS IN THE CLOUDS IN ITS WAKE...AREAS OF
IFR/LIFR IN FOG FORMING LATE...IN WAKE OF THE RAIN SHOWERS...FROM
EASTERN OHIO ACROSS NORTHERN WEST VIRGINIA INCLUDING PKB TO
CKB...AND EVEN TOWARD W22 AND EKN...FOR A BRIEF TIME AROUND 10Z TO
12Z. MAINLY MVFR IN FOG FURTHER SOUTH TOWARD CRW AND THE SOUTHERN
WV COAL FIELDS.
THE UPSLOPE FLOW ALONG THE EASTERN SLOPES OF THE APPALACHIANS
IS WEAK AND BECOMES MORE SOUTHERLY BY MIDDAY TODAY. THIS LOWERS MY
CONFIDENCE IN THE CEILINGS ALONG THE SPINE OF THE APPALACHIANS ON
EAST INTO THE GREENBRIER VALLEY. BECKLEY IN THE SOUTHERN MOUNTAINS
MAY BE ON THE WESTERN FRINGE OF THIS MAXIMUM IN LOW LEVEL MOISTURE
THIS MORNING...SO HAVE A SCATTERED TO BROKEN DECK THERE AROUND 2
THSD FT AGL.
IN DAYTIME HEATING HAVE SCATTERED TO BROKEN CLOUDS MOSTLY 2 TO 4
THSD FT AGL EXCEPT 4 TO 6 THSD FT ACROSS NORTHERN WV LOWLANDS.
A FEW SHOWERS OR THUNDERSTORMS COULD FORM IN THE AFTERNOON HEATING
OVER THE MOUNTAINOUS COUNTIES. INSTABILITY INCREASES IN THE TRI
STATE VCNTY OF HTS BY 21Z INCLUDING EASTERN KENTUCKY...SO SOME
THUNDERSTORMS COULD DEVELOP THERE LATE TODAY AND LINGER TONIGHT.
WITH MOISTURE INCREASING AT 850 MB AND BELOW WEST OF THE MOUNTAINS
TONIGHT...HAVE MORE WIDESPREAD CEILINGS A 3 TO 4 THSD FT DEVELOPING
00Z TO 06Z WEDNESDAY IN THE WESTERN LOWLANDS. VSBY COULD BE 5 TO 6
MILES IN HAZE WITH INCREASING SURFACE DEW POINTS. INSTABILITY
LINGERS OVERNIGHT...SO HAVE CHANCE POPS FOR CONVECTION CREEPING NE
INTO CENTRAL WV AND CRW VCNTY. EXPECTING DRY CONDITIONS TO HOLD
PKB TO CKB VCNTY OVERNIGHT THRU 12Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: EARLY MORNING FOG IN WAKE OF THE RAIN COULD
LINGER AN HOUR LONGER. COVERAGE AND TIMING OF ANY OVERNIGHT CONVECTION
COULD VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY M M H H H H H H H H H H
HTS CONSISTENCY M M H H H H H H H H H H
BKW CONSISTENCY M M M M M M H H H H M M
EKN CONSISTENCY L M M H H H H H H H H H
PKB CONSISTENCY L L H H H H H H H H H H
CKB CONSISTENCY L L H H H H H H H H H H
AFTER 18Z WEDNESDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION WEDNESDAY INTO SATURDAY. IN HUMID
AIR IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE CONVECTION...
ESPECIALLY AT NIGHT AND INTO THE MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...JSH
AVIATION...KTB
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1238 PM CDT TUE AUG 6 2013
.UPDATE...
UPDATED AVIATION DISCUSSION BELOW FOR 18Z TAFS.
WEAK SURFACE LOW PRESSURE AREA IN SOUTHEAST ND MOVING EAST LATE
THIS MORNING WITH A WEAK COOL FRONT DROPPING IN BEHIND IT. MOST OF
THE CONVECTION WAS OVER THIS MORNING. THE HRRR MODEL WAS SHOWING
SOME REDEVELOPMENT OVER FAR NE SD/WC MN THIS AFTERNOON AND EVENING
AND ALSO ALONG THE WEAK COOL FRONT DROPPING IN FROM THE NORTH.
THUS...ADJUSTED POPS DOWNWARD ACROSS MOST OF THE REGION THROUGH
THE AFTERNOON.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH THURSDAY
PRECIPITATION CHANCES TODAY WILL BE THE MAIN FORECAST CHALLENGE.
THUNDERSTORMS CURRENTLY ONGOING ALONG AND SOUTH OF I-90 SHOULD
CONTINUE TO DRIFT ESE...CLIPPING ONLY THE SOUTHWEST PORTION OF THE
CWA THROUGH THE MID MORNING HOURS. ADDITIONAL CONVECTION IS MOVING
DUE EAST ALONG I-94 IN NORTH DAKOTA. THESE STORMS SHOULD REMAIN NORTH
OF THIS CWA THROUGH THE MORNING HOURS.
MODELS SORT OF AGREE WITH TWO POSSIBLE CLUSTERS OF STORMS
DEVELOPING LATER THIS AFTERNOON. ONE CLUSTER WOULD BE ACROSS
SOUTHEAST SOUTH DAKOTA WHERE BETTER INSTABILITY IS LOCATED ALONG
WITH A WEAK MID LEVEL SHORT WAVE. IF THIS ACTIVITY DEVELOPS...IT
SHOULD REMAIN SOUTH OF THIS CWA. THE SECONDARY CLUSTER WILL BE
ALONG A SLOWLY SOUTHWARD SINKING COLD FRONT. LESS INSTABILITY
ALONG THE FRONT...BUT SLIGHTLY BETTER 0-6 KM BULK SHEAR MAY RESULT
IN A FEW STRONGER STORMS IN NORTHEAST SOUTH DAKOTA AND WESTERN
MINNESOTA LATER THIS AFTERNOON.
A COOL CANADIAN HIGH PRESSURE SETTLING ACROSS THE REGION WILL
BRING DRY AND TRANQUIL CONDITIONS FOR WEDNESDAY AND FOR MOST OF
WEDNESDAY NIGHT. THEN ANOTHER SURFACE LOW PRESSURE SYSTEM WILL
MOVE ACROSS THE REGION DURING THE EARLY MORNING HOURS ON THURSDAY.
THERE SEEMS TO BE A GENERAL CONSENSUS WITH MOST OF THE CONVECTION
OCCURRING ACROSS SOUTHERN NORTH DAKOTA. THERE IS STILL A CHANCE
FOR THUNDERSTORMS ACROSS MOST OF THE CWA AS A TRAILING COLD FRONT
MOVES SOUTHWARD ACROSS THE CWA ON THURSDAY. SIGNIFICANTLY LESS
INSTABILITY SHOULD RESULT IN GENERAL THUNDERSTORMS.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY NIGHT
NO CHANGES FROM 24 HOURS AGO. NORTHWEST FLOW WILL STEER ONE OR
MORE MID-LEVEL SHORTWAVES THROUGH THE REGION ATOP A DECENT LOW TO
MID-LEVEL BAROCLINIC ZONE...RESULTING IN A COUPLE HALFWAY DECENT
CHANCES FOR MEASURABLE PRECIP OVER A GOODLY AMOUNT OF AREAL
COVERAGE OF THE CWA. SEEMS THE BEST CHANCES FOR PRECIPITATION...RIGHT
NOW...ARE ANCHORED ON FRIDAY NIGHT THROUGH SUNDAY MORNING. 925HPA
AND 850HPA THERMAL PROGS IN THE GFS AND ECMWF SUGGEST TEMPERATURES
WILL REMAIN GENERALLY NEAR TO BELOW NORMAL THROUGH THE PERIOD.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD. AS OF 18Z A
BAND OF -SHRA STRETCHES FROM WESTERN THROUGH CENTRAL SD. HAVE
INCLUDED VCSH AT KPIR FOR THE AFTERNOON HOURS TO ACCOUNT FOR THIS.
OTHERWISE...AS A FRONTAL BOUNDARY MOVES ACROSS THE REGION
TODAY...A FEW SHRA/TSRA ARE POSSIBLE...MAINLY OVER EASTERN
PORTIONS OF THE AREA. HAVE INCLUDED A VCTS MENTION AT KATY LATER
THIS AFTERNOON. W/NW WINDS WILL BECOME MORE N/NE OVERNIGHT AS THE
MAIN PUSH OF COOLER AIR WORKS ITS WAY SOUTH OVER THE AREA. LIGHT
WINDS AND VFR CONDITIONS CAN BE EXPECTED ON WEDNESDAY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR/TMT
SHORT TERM...CONNELLY
LONG TERM...DORN
AVIATION...TMT
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
131 PM MDT TUE AUG 6 2013
.SYNOPSIS...
AFTER ANOTHER ROUND OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
THIS EVENING AND OVERNIGHT...WE`LL SEE A DECREASE IN STORM ACTIVITY
THROUGH EARLY FRIDAY AFTERNOON AS HIGH PRESSURE ALOFT SERVES TO CAP
MOST STORM ACTIVITY EXCEPT IN AREA MOUNTAINS. THE RISK OF RAIN WILL
INCREASE FRIDAY NIGHT AND SATURDAY AS A BACKDOOR COLD FRONT MOVES
NEAR THE REGION BY EARLY FRIDAY AND SOUTHEAST SURFACE WINDS BRING
ADDITIONAL MOISTURE. LATER IN THE WEEKEND AND EARLY NEXT WEEK WE
SHOULD RETURN TO A WEAK MONSOON PATTERN WITH THE BEST CHANCES OF
STORMS OVER FAR WESTERN PORTIONS OF THE AREA.
&&
.DISCUSSION...
NOT MUCH CHANGE FROM PREVIOUS THINKING. HRRR BRINGS A CLUSTER OF
STORMS NORTH OVER MEXICO THIS EVENING BUT DIMINISHES ACTIVITY AS
IT APPROACHES EL PASO/HUDSPETH COUNTIES. MAY REGRET IT BUT I PUSHED
POPS ABOVE MOS OVER THAT AREA FOR 1ST PERIOD.
OTHERWISE UPPER HIGH BUILDS BACK INTO REGION FOR TOMORROW THROUGH
MOST OF FRIDAY BEFORE BACKDOOR COLD FRONT MOVES INTO EASTERN PLAINS
OF NM FRIDAY. OVERALL LOWER POPS EXPECTED. GIVEN THE USUAL POOR
PERFORMANCE OF MODELS IN HANDLING THESE BACKDOORS...I WOULDN`T BE
SURPRISED TO HAVE A FRONTAL PASSAGE LATER FRIDAY INTO EARLY
SATURDAY. IN THIS CASE IT WON`T MAKE AS MUCH DIFFERENCE AS IT
USUALLY WOULD SINCE WINDS AHEAD OF THE FRONT WILL SWING TO THE SE
AND RETURN TROPICAL MOISTURE INTO THE REGION. THIS WILL GIVE THE
BEST CHANCE OF SHOWERS AND STORMS AFTER THIS EVENING. IF THE FRONT
ARRIVES RAINFALL WOULD BE HEAVIER AND POSSIBLE SEVERE STORMS WOULD
COME INTO PLAY.
AFTER THAT THE UPPER HIGH AND BUILDS BACK OVER THE AREA GRADUALLY
DIMINISHING STORMS ONCE AGAIN INTO EARLY NEXT WEEK.
&&
.AVIATION...VALID 07/00Z-08/00Z.
MOSTLY VFR THRU THE PERIOD. 00Z-09Z SCATTERED TSRAGS 3SM BKN060CB
TOPS 420. ISOLD AREAS MVFR TO VFR IN/NR TSTMS. SURFACE WINDS
SOUTHWEST 12-22KTS...EXCEPT FOR WIND GUSTS TO 45 KTS NEAR STORMS.
AFT 09Z SCT080 SCT-BKN 100-200. ISOLD -SHRA UNTIL 18Z THEN VERY
ISOLD TS ALL AREAS ESPLY MTNS AND WINDS WSW 15G25KTS.
&&
.FIRE WEATHER...
HIGH PRESSURE ALOFT OVER NORTHEAST TEXAS WILL AGAIN CHANNEL THE
DEEPER MOISTURE MAINLY OVER SOUTHWESTERN NEW MEXICO WITH SCATTERED
AFTERNOON THUNDERSTORMS. AN UPPER TROUGH OVER ARIZONA WILL ALSO
PROVIDE SOME ADDITIONAL DYNAMICS FOR THUNDERSTORM DEVELOPMENT MAINLY
WEST OF THE RIO GRANDE. EAST OF THE RIO GRANDE THUNDERSTORM
DEVELOPMENT WILL BE MORE ISOLATED. THE UPPER TROUGH OVER ARIZONA IS
FORECAST TO MOVE ACROSS NEW MEXICO WEDNESDAY BRINGING WIDELY
SCATTERED THUNDERSTORMS BUT THEN USHER IN DRIER AIR LATER IN THE
DAY. WITH DRIER AIR...THERE WILL BE ONLY A FEW MOUNTAIN
THUNDERSTORMS ON THURSDAY. A POSSIBLE WEAK BACK DOOR FRONT WILL MOVE
IN TO THE AREA EARLY FRIDAY SHIFTING THE WINDS TO THE SOUTHEAST
THEREBY INCREASING THE MOISTURE AT LOWER LEVELS FRIDAY INTO THE
WEEKEND. THIS WILL INCREASE THUNDERSTORMS ACROSS THE AREA WITH
TEMPERATURES STILL REMAINING MAINLY ABOVE NORMAL. MIN RH VALUES
WILL GENERALLY RUN IN THE 25% TO 35% RANGE ALL AREAS TUESDAY AND
WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
EL PASO 74 92 75 94 74 / 30 10 10 10 10
SIERRA BLANCA 68 94 69 95 71 / 30 10 20 20 20
LAS CRUCES 68 91 67 91 69 / 10 10 10 10 10
ALAMOGORDO 71 93 68 94 68 / 20 10 20 10 10
CLOUDCROFT 51 67 51 69 49 / 20 20 20 20 20
TRUTH OR CONSEQUENCES 67 90 67 90 67 / 20 30 10 10 10
SILVER CITY 60 79 58 83 60 / 30 30 10 10 10
DEMING 67 89 64 91 65 / 20 20 10 10 10
LORDSBURG 63 87 63 90 65 / 30 20 10 10 10
WEST EL PASO METRO 74 92 73 94 74 / 30 10 10 10 10
DELL CITY 70 95 69 97 67 / 10 10 10 10 10
FORT HANCOCK 73 95 72 97 72 / 30 10 10 10 20
LOMA LINDA 65 86 66 88 67 / 30 10 10 10 10
FABENS 73 93 71 95 71 / 30 10 10 10 10
SANTA TERESA 70 92 71 93 71 / 30 10 10 10 10
WHITE SANDS HQ 70 92 70 92 69 / 10 10 10 10 10
JORNADA RANGE 67 92 67 92 67 / 10 20 10 10 10
HATCH 66 88 67 89 67 / 20 20 10 10 10
COLUMBUS 66 89 67 91 67 / 20 10 10 10 10
OROGRANDE 72 93 71 94 69 / 20 10 10 10 10
MAYHILL 59 78 58 78 55 / 20 20 20 20 20
MESCALERO 57 79 56 80 56 / 20 20 20 20 20
TIMBERON 57 76 58 77 56 / 20 10 10 20 20
WINSTON 57 78 58 80 57 / 20 40 20 20 10
HILLSBORO 63 84 62 86 63 / 20 30 10 20 10
SPACEPORT 67 90 67 91 67 / 20 20 10 10 10
LAKE ROBERTS 58 78 55 82 58 / 30 40 20 20 10
HURLEY 62 81 61 86 62 / 30 30 10 10 10
CLIFF 61 84 60 88 61 / 40 40 10 20 10
MULE CREEK 56 80 56 85 58 / 40 40 10 10 10
FAYWOOD 63 82 61 85 63 / 20 30 10 10 10
ANIMAS 63 87 65 89 65 / 30 30 20 10 10
HACHITA 64 88 64 90 66 / 30 20 10 10 10
ANTELOPE WELLS 63 86 63 89 65 / 30 30 20 20 10
CLOVERDALE 61 80 61 84 63 / 30 30 20 10 10
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
&&
$$
02/20