Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/16/12
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1103 PM MDT MON AUG 13 2012
.AVIATION...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE
ACROSS SOUTHERN PORTIONS OF SOUTH CENTRAL AND SOUTHEAST
COLORADO...WITH ISOLATED -TSRA MOST LIKELY TO AFFECT KALS THROUGH
08Z. BRIEF VFR CIGS/VIS IN LIGHT RAIN ALONG WITH WIND GUSTS TO 20
KTS WILL BE POSSIBLE WITH THUNDERSTORMS. KPUB AND KCOS WILL LIKELY
REMAIN DRY WITH VFR CIGS POSSIBLE AT TIMES...ESPECIALLY AT KPUB AS
MID CLOUD DECK REMAINS OVER THE AREA. SKIES WILL GRADUALLY CLEAR
TOWARDS MORNING. MUCH LESS WIDESPREAD -TSRA ACTIVITY IS EXPECTED
FOR TUESDAY...WITH ONLY ISOLATED -TSRA POSSIBLE AT KCOS AND KALS.
PROBABILITY LOOKS TOO LOW TO WARRANT INCLUSION IN TAF SITES AT
THIS TIME. -KT
&&
.PREV DISCUSSION... /ISSUED 318 PM MDT MON AUG 13 2012/
SHORT TERM...
(TONIGHT AND TOMORROW)
..SCATTERED STORMS FOR EVERYONE NEXT 6-9 HOURS OR SO...
CURRENTLY...
WATER VAPOR AT 2 PM SHOWS A HEALTHY DISTURBANCE UP IN WYOMING AND IT
WAS MOVING EAST SOUTHEAST TOWARDS THE REGION. A RATHER LARGE AREA OF
RAIN WAS NOTED OVER THE GENERAL NW SXTNS OF THE STATE OF CO...WITH
QUITE A FEW SHOWER SURROUNDING THIS AREA OF RAIN. A COUPLE OF
VORTICES WERE IMPLIED IN THE RAIN SHIELD (ORIENTATION OF CURVED
RAINSHIELD ON RADAR IMGY)...WITH ONE NW OF LARAMIE AND ANOTHER
ENTERING NW CO.
REST OF TODAY AND INTO TONIGHT...
SHOWERS AND STORMS WILL CONTINUE TO INCREASE IN COVERAGE OVER THE
REGION...AND THERE IS A PRETTY GOOD CHANCE NEARLY ALL OF US WILL SEE
SOME RAIN DURING THE NEXT 9 HOURS OR SO. PRECIP WAS ALREADY
DEVELOPING ON THE PLAINS AS I WRITE (2 PM) AND HRRR FCST THIS TO
EXPAND AND MOVE TO THE EAST-SOUTHEAST. EVEN GFS HAS A LARGE BULLSEYE
OF PRECIP OVER THE FAR SE PLAINS LATER TODAY. AS FOR THE BURN
SCAR...LATEST HI RES GUIDANCE SHOWS THE BEST CHANCE BETWEEN 3 AND 5
PM. LOCALLY HEAVY RAIN COULD OCCUR BUT I AM NOT ALL THAT CONFIDENT
AS IT MAY BE TOO STABLE FOR ANY HEAVIER RAIN OVER THE SCAR...HOWEVER
I AM PRETTY CERTAIN THEY WILL GET MORE PRECIP TODAY. PRECIP OVER THE
REST OF THE MTNS WILL CONTINUE TO BLOSSOM AS THE AFTERNOON
PROGRESSES.
SHOWERS AND STORMS WILL BE ONGOING ACROSS THE PLAINS THIS EVENING.
ACTIVITY OVER THE MTNS WILL STILL BE ONGOING...BUT WILL BE ON A
GRADUAL DOWNWARD TREND AS THE EVENING PROGRESSES. I WOULD EXPECT BY
MID EVENING THE HEAVIEST STORMS WILL BE OVER THE EASTERN
PLAINS...ESPECIALLY THE FAR E PLAINS. A FEW STRONGER STORMS WILL BE
POSSIBLE BUT WILL ONLY BE MARGINALLY SEVERE AT BEST GIVEN THE
LIMITED CAPE/SHEAR FIELDS CURRENTLY IN PLACE.
BY MIDNIGHT...ISOLATED PRECIP MAY BE OVER THE MTNS WITH PRECIP OVER
THE FAR E PLAIN MOVING OUT OF THE STATE.
TOMORROW...
RATHER STABLE AIRMASS WILL LIKELY BE OVER THE PLAINS AND DO NOT
EXPECT ANY PRECIP. THE ONLY EXCEPTION MAY BE THAT PART OF THE PLAINS
ABOVE 6000 FEET WHICH MAY SEE A SHOWER LATE IN THE DAY. THE MTNS
WILL CONTINUE TO SEE SCTD COVERAGE..ESPECIALLY ALONG THE CONTDVD. I
DID KNOCK DOWN TEMPS A FEW DEGREES AS IT WILL LIKELY BE A BIT COOLER
TOMORROW THAN EARLIER ADVERTISED.
LONG TERM...
(TUESDAY NIGHT THROUGH MONDAY)
TUESDAY NIGHT THROUGH WEDNESDAY AFTERNOON...AS THE UPPER WAVE
DEPARTS AND THE RIDGE CONTINUES TO BREAK DOWN...SUBSIDENCE SHOULD
RESTRICT CONVECTION TO THE MTS THROUGH THE EVE...THEN THE TYPICAL
ISOLATED TO LOW SCATTERED CONVECTION FOR THE MTS WED AFTN. A WARM
AND BREEZY DAY IS ON TAP FOR WED...AHEAD OF THE NEXT INCOMING SFC
FRONT.
WEDNESDAY NIGHT THROUGH FRIDAY...MODELS INDICATE A RATHER STRONG
SHORTWAVE DROPS DOWN OUT OF CANADA AND ACROSS THE NORTHERN PLAINS ON
WED...PUSHING A SFC FRONT DOWN INTO COLORADO WED EVE. NAM MODEL
SHOWS A PRE-FRONTAL NORTHERLY PUSH THROUGH THE DAY WED...WITH THE
TRUE SFC FRONT CROSSING THE PALMER DVD RIGHT BETWEEN 00Z AND 06Z.
SO...NORTHERLY WINDS LATE WED NIGHT INTO THU MORNING...WITH WINDS
SWINGING AROUND TO THE EAST BY THU AFTN. PCPN SHOULD BE FAIRLY
WIDESPREAD LATE WED NIGHT AND LINGER INTO THE EARLY MORNING HRS OF
THU...THEN FIRE UP AGAIN QUICKLY ON THU WITH UPSLOPE SHOVING THE
MOISTURE UP AGAINST THE SOUTHERN FRONT RANGE. PCPN WILL TAPPER OFF
FROM N TO S THU EVE...THEN A LITTLE LESS COVERAGE IS THEN FORECAST
FOR FRI. MAX TEMPS ON THU ARE CURRENTLY FORECAST TO WARM INTO THE
70S TO NEAR 80 F FOR THE PLAINS...BUT WITH THE EXPECTED CLOUD COVER
THIS MAY BE SLIGHTLY TOO WARM...AND WILL HAVE TO REVISIT MAX TEMP
GRIDS AGAIN OVER THE NEXT FEW MODEL RUNS. THE COOL TEMPS SHOULD
CARRY OVER INTO FRI AS THE LLVL COOL AIR AND MOISTURE GRADUALLY
ERODES.
SATURDAY THROUGH MONDAY...UPPER RIDGE STRENGTHENS OVER THE WESTERN
US FOR THE WEEKEND...WITH CONVECTIVE ACTIVITY SLIPPING BACK INTO A
DIURNAL PATTERN WITH MORE ISOLATED COVERAGE TIED TO THE HIGHER
TERRAIN. GFS MODEL IS INDICATING A LOT MORE POSSIBLE PCPN OVER THE
PLAINS...WHICH IS LIKELY A RESULT OF THE RIDGE BREAKING DOWN FASTER
THAN WHAT THE ECMWF SHOWS...SO WILL MAINTAIN THE FORECAST OF DIURNAL
MT CONVECTION AND MAX TEMPS CLIMBING BACK INTO THE 90S FOR THE
PLAINS AND 80S FOR THE HIGH VALLEYS. 27
AVIATION...
ALL TAFS SITES WILL SEE STORMS TODAY. A FEW SHOWERS HAVE ALREADY
MOVED ACROSS KALS AND KCOS AS PER RADAR IMGY. WITH THE VORT MAX
MOVING ACROSS THE AREA LATER TODAY AND EARLY THIS EVENING SCATTERED
STORMS WILL MOVE ACROSS THE TAF SITES...WITH THE BEST CHANCE BETWEEN
3 AND 7 PM AT KCOS AND 3 AND 8 PM ACROSS KPUB. SHOWERS WILL MOVE
ACROSS KALS BETWEEN NOW AND 8 PM THIS EVENING. CIGS SHOULD REMAIN
ABOVE MVFR BUT WE MAY SEE BRIEF HVY RAINS WHICH WILL BRING MVFR
CONDITIONS TO THE TAF SITES.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31/44
AREA FORECAST DISCUSSION
NWS ALBANY NY
146 PM EDT TUE AUG 14 2012
.SYNOPSIS...
LOW PRESSURE WILL APPROACH FROM THE LOWER GREAT LAKES
REGION...AND THE OHIO VALLEY THIS AFTERNOON WITH AN INCREASING
THREAT OF SHOWERS AND THUNDERSTORMS INTO THIS EVENING. THE
UNSETTLED WEATHER WILL CONTINUE INTO THE MID WEEK PERIOD...BEFORE
HIGH PRESSURE BRINGS FAIR AND DRY WEATHER FOR THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 100 PM EDT...A WEAK VORT MAX IN THE SW FLOW VIA THE LATEST
RUC40 HAS PRODUCED SOME LIGHT SHOWERS SOUTH OF THE CAPITAL REGION.
IT HAS ALSO PRODUCED PLENTY OF MID AND HIGH CLOUDS ACROSS THE FCST
AREA VIA THE LATEST VISIBLE AND IR TRENDS. THERE WILL LIKELY BE A
BRIEF BREAK BEFORE THE NEXT SHORT-WAVE ASSOCIATED WITH THE TROUGH
OF LOW PRESSURE APPROACHES FROM THE SOUTH AND WEST IN THE LATER
AFTERNOON. EVIDENCE OF THIS IMPULSE ARE THE SHOWERS AND
THUNDERSTORMS MOVING INTO WRN NY AND THE NIAGARA FRONTIER.
WE LOWERED THE CONVECTIVE CHANCES TO SLIGHT CHC VALUES PRIOR TO 6
PM DUE TO THE CANOPY OF CLOUDS AND THE LACK OF INSTABILITY. THE
LATEST SPC MESOANALYSIS SHOWS SBCAPE AND MLCAPE VALUES OF 200-500
J/KG OVER THE FCST AREA. THE MID LEVEL LAPSE RATES REMAIN WEAK
TOO. WE LOWERED MAX TEMPS A FEW MORE DEGREES...BUT KEPT SOME LOWER
80S NORTH AND EAST OF THE CAPITAL REGION WHERE A LITTLE MORE
SUNSHINE WILL OCCUR THROUGH THE CLOUDS.
THE CHANCE OF SHOWERS AND THUNDERSTORMS INCREASE ACROSS THE SRN
DACKS AND CNTRL BTWN 21Z-00Z BASED ON THE LATEST HRRR 3KM COLUMNAR
BASED REF PRODUCT WITH THE SHORT-WAVE.
PREVIOUS DISCUSSION...
EXPECT AN INCREASING CHANCE OF SHOWERS AND SOME THUNDERSTORMS
FROM LATER THIS MORNING INTO TONIGHT WITH MORE SHOWERS AND
THUNDERSTORMS WEDNESDAY INTO WEDNESDAY EVENING AS THE UPPER
TROUGH PASSES THROUGH THE REGION. AT THIS POINT IN TIME IT APPEARS
THE BEST CHANCE FOR THUNDERSTORMS WHICH MAY PRODUCE LOCALLY HEAVY
RAIN WOULD BE LATER THIS AFTERNOON INTO EARLY THIS EVENING WHEN
FIRST H10-H8 THETA E RIDGE AXIS PEAKS ACRS FA WITH SHOWALTER
INDICES AT OR SLIGHTLY BELOW ZERO...MLMUCAPES 300-1000 J/KG AND
PWATS ARND 1.5 INCHES. THE SECOND MOST ACTIVE PERIOD IS EXPECTED
TO BE WEDNESDAY AFTERNOON WITH SLIGHTLY HIGHER PWATS IN THE 1.5 TO
1.67 INCH RANGE...SHOWALTER INDICES SLIGHTLY MORE
NEGATIVE...STRONGER THETA E RIDGE AND MLMUCAPES GREATER BTWN 1500
AND 3000 J/KG.
THE CHANCE OF SEVERE WEATHER REMAINS UNCERTAIN AT THIS TIME AS
PLENTY OF CLOUD COVER DURING THE MID WEEK PERIOD MAY REDUCE
SURFACE HEATING AND CAPES AND H7-H5 LAPSE RATES RATHER
UNIMPRESSIVE UNTIL WEDNESDAY WHEN IT REACHES ABOVE 6 C/KM ACRS
PORTIONS OF THE FA. WEDNESDAY MAY HAVE THE BETTER CHANCE OF MORE
ORGANIZED CONVECTION WITH SLIGHTLY BETTER SHEAR AND 0-3 KM
HELICITY. AT THIS POINT WILL CONTINUE WITH PREVIOUS WORDING IN HWO
MENTIONING A FEW STORMS MAY HAVE DAMAGING WIND GUSTS ON WEDNESDAY.
EXPECT HIGHS TODAY IN THE MID 70S TO MID 80S AND ON WEDNESDAY IN
THE 70S TO LOWER 80S. LOWS TONIGHT ARE EXPECTED TO BE IN THE
UPPER 50S TO UPPER 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
ON WED NIGHT...EXPECT THE UPPER TROUGH AXIS TO SWING THROUGH THE
FA BY LATE EVENING WITH THE THREAT OF SHOWERS DIMINISHING DURING
THE SECOND HALF OF THE NIGHT AND LOWS IN THE MID 50S TO MID 60S.
ON THURSDAY RIDGING BUILDS ACRS THE FA AT THE SURFACE AND ALOFT
AND SLIDES EAST OF THE FA THURSDAY NIGHT PROVIDING DRY AND
SEASONABLE CONDITIONS. EXPECT HIGHS ON THURSDAY IN THE UPPER 70S TO
LOW TO MID 80S WITH LOWS THURSDAY NIGHT IN THE MID 50S TO LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
HAVE GENERALLY USED A 50/50 BLEND OF 18Z/13 HPC GUIDANCE AND 00Z/14
GMOS FOR THIS PORTION OF THE GRIDDED DATABASE...ALTHOUGH SKEWED
POPS/WEATHER TOWARD THE 00Z/14 ECMWF FOR LATE FRI-SAT EVENING.
FRIDAY...COLD FRONT SHOULD APPROACH FROM THE WEST IN THE AFTERNOON.
HOWEVER...MODELS VARY CONSIDERABLY ON TIMING...WITH THE 00Z/14 GFS
AND GEFS MOST PROGRESSIVE...AND THE 00Z/14 ECMWF SLOWEST. WILL
INDICATE CHC POPS...MAINLY IN THE AFTERNOON HOURS FOR SCATTERED
SHOWERS/TSTMS. EXPECT A WARM AND SOMEWHAT HUMID DAY...WITH MAX TEMPS
REACHING THE LOWER/MID 80S IN VALLEYS...AND 75-80 ACROSS HIGHER
TERRAIN. SHOULD CLOUDS/SHOWERS HOLD OFF UNTIL LATER IN THE
DAY...EVEN WARMER MAX TEMPS COULD OCCUR.
FRI NT-SAT NT...LOW DEGREE OF CONFIDENCE DURING THIS TIME
PERIOD...AS LATEST 00Z/14 ECMWF HAS TRENDED BACK TO A SLOWER
FROPA...WITH WAVE FORMATION ALONG THE BOUNDARY ACROSS THE NORTHERN
MID ATLANTIC STATES TRACKING NE INTO SOUTHERN NEW ENGLAND...IMPLYING
A RATHER WET SATURDAY...WHILE THE 00Z/14 GFS AND GEFS MEAN CONTINUE
WITH A MORE PROGRESSIVE SYSTEM...WITH DRY WEATHER FOR LATE FRI NT
INTO SAT. WILL SIDE CLOSER TO THE ECMWF...AND LINGER CHC POPS ACROSS
MUCH OF THE REGION FOR FRI NT AND EARLY SAT...AND THEN SLOWLY TAPER
POPS FROM NW TO SE SAT AFTERNOON/EVENING. EXPECT MIN TEMPS TO FALL
INTO THE LOWER 60S IN VALLEYS...AND 50S ACROSS HIGHER TERRAIN FOR
FRI NT/SAT AM...WITH MAX TEMPS SAT MAINLY IN THE 70S WITHIN
VALLEYS...AND 65-70 ACROSS HIGHER ELEVATIONS. HOWEVER...EVEN COOLER
MAXES COULD OCCUR IN VALLEY REGIONS SHOULD CLOUDS AND RAIN PERSIST
THROUGH THE AFTERNOON HOURS. SAT NT/SUN AM SHOULD BE COOLER...WITH
MINS FALLING INTO THE 50S IN MOST VALLEYS...AND 45-50 ACROSS HIGHER
ELEVATIONS.
SUN-MON...AT THIS TIME...WILL INDICATE FAIR AND SEASONABLY COOL
CONDITIONS...AS HIGH PRESSURE BUILDS IN FROM THE WEST. EXPECT MAX
TEMPS TO REACH 75-80 IN VALLEY AREAS...AND 70-75 ACROSS HIGHER
ELEVATIONS...WHILE OVERNIGHT MINS FALL INTO THE LOWER/MID 50S IN
MOST VALLEYS...AND 45-50 ACROSS HIGHER ELEVATIONS.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
WEAK LOW PRESSURE ACROSS THE OHIO VALLEY REGION WILL APPROACH FROM
THE SOUTHWEST THROUGH TONIGHT. THIS WILL BRING INTERVALS OF
SCATTERED SHOWERS TO THE REGION THROUGH TOMORROW MORNING.
AT THIS TIME...IT APPEARS THAT THE CHANCE FOR THUNDER IS QUITE
LOW...AND THEREFORE WILL KEEP MENTION OUT OF CURRENT SUITE OF
TAFS. ONE AREA OF SHOWERS IS AFFECTING KALB ...KPOU AND KPSF WITH
SOME SPRINKLES. SO...VCSH AT THOSE SITES THROUGH ABOUT 20Z. THERE
LOOKS TO BE A BREAK IN THE SHOWER ACTIVITY INTO THIS EVENING...BUT
RADAR SHOWS MORE SCATTERED SHOWERS TO THE WEST THAT LOOK TO BE
TIMED IN OUR REGION SOME TIME THIS EVENING AND TONIGHT...AS LONG
AS THEY HOLD TOGETHER. MOVEMENT OF THE BAND OF SHOWERS AND
ISOLATED THUNDERSTORMS LOOKS TO BE SLOW MOVING...AND WITH
UNCERTAINTIES IN TIMING BREAKS BETWEEK SHOWERS THROUGH TOMORROW
MORNING...HAVE PUT VCSH IN MOST TIME PERIODS IN ALL TAFS THROUGH
TOMORROW MORNING. SOME MVFR FOG IS POSSIBLE BETWEEN 06Z AND 12Z
DEPENDING ON THE SHOWERS ACTIVITY IR LACK THEREOF. AGAIN...WITH
GUIDANCE SUGGESTING SCATTERED SHOWERS THROUGH TOMRROW
MORNING...AND BASED ON THE CHARACTER OF THE BANS OF SHOWERS WELL
TO THE WEST...PUTTING VCSH TONIGHT THROUGH TOMORROW MORNING. AFTER
12Z...EVEN WITH SHOWRS AROUND...CEILINGS AND VISIBILITIES SHOULD
BE VFR OUTSIDE OF SHOWER ACTIVITY.
NEARLY CALM WINDS WILL OCCASIONALLY BE SOUTHWEST TO SOUTH AT 5-10
KT THROUGH THE PERIOD.
OUTLOOK...
TUE NT-WED...VFR/MVFR. CHC SHRA/TSRA.
WED NT-THU...MAINLY VFR. NO SIG WX EXP AT THIS TIME. CHC MVFR/IFR
WITH BR/FG AT NIGHT.
FRI/SAT...VFR/MVFR. CHC SHRA/TSRA.
SUN...VFR...NO SIG WX.
&&
.FIRE WEATHER...
LOW PRESSURE WILL APPROACH FROM THE LOWER GREAT LAKES REGION...AND
THE OHIO VALLEY TODAY WITH AN INCREASING THREAT OF SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON AND EVENING. THE UNSETTLED WEATHER
WILL CONTINUE INTO THE MID WEEK PERIOD...BEFORE HIGH PRESSURE
BRINGS FAIR AND DRY WEATHER FOR THURSDAY.
RELATIVE HUMIDITIES ARE EXPECTED TO DROP TO 45 TO 70 PERCENT
TODAY...RECOVER TO 80 TO 100 PERCENT TONIGHT...AND FALL TO 60 TO
80 PERCENT ON WEDNESDAY.
WINDS ARE EXPECTED TO BE SOUTH TO SOUTHWEST AT 5 TO 10 MPH
TODAY...SOUTHWEST TO WEST AROUND 5 MPH TONIGHT...AND SOUTHWEST AT
5 TO 10 MPH ON WEDNESDAY.
&&
.HYDROLOGY...
AT THIS TIME...NO PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THE
NEXT 5 DAYS.
MAINLY DRY WEATHER IS EXPECTED THROUGH EARLY THIS MORNING
FOLLOWED BY INCREASING SHOWERS AND SOME THUNDERSTORMS FOR THE MID
WEEK PERIOD. DRY WEATHER IS THEN EXPECTED FOR MUCH OF THE AREA
WEDNESDAY NIGHT THROUGH FRIDAY MORNING WITH MORE UNSETTLED WEATHER
FRIDAY AFTERNOON INTO SATURDAY. TOTAL RAINFALL AMOUNTS THROUGH
WEDNESDAY ARE GENERALLY EXPECTED TO RANGE FROM TWO THIRDS OF AN
INCH TO JUST UNDER AN INCH AND A HALF. HOWEVER...AREAS WHICH
RECEIVE MORE NUMEROUS THUNDERSTORMS CAN EXPECT LOCALIZED HIGHER
AMOUNTS.
DRY WEATHER RETURNS FOR THURSDAY BEFORE A COLD FRONT APPROACHES
FOR FRIDAY INTO THE WEEKEND WITH MORE SHOWERS AND THUNDERSTORMS.
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...WASULA
NEAR TERM...NAS/WASULA
SHORT TERM...11
LONG TERM...KL
AVIATION...NAS
FIRE WEATHER...11
HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
105 PM EDT TUE AUG 14 2012
.SYNOPSIS...LOW PRESSURE WILL APPROACH FROM THE LOWER GREAT LAKES
REGION...AND THE OHIO VALLEY THIS AFTERNOON WITH AN INCREASING
THREAT OF SHOWERS AND THUNDERSTORMS INTO THIS EVENING. THE
UNSETTLED WEATHER WILL CONTINUE INTO THE MID WEEK PERIOD...BEFORE
HIGH PRESSURE BRINGS FAIR AND DRY WEATHER FOR THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 100 PM EDT...A WEAK VORT MAX IN THE SW FLOW VIA THE LATEST
RUC40 HAS PRODUCED SOME LIGHT SHOWERS SOUTH OF THE CAPITAL REGION.
IT HAS ALSO PRODUCED PLENTY OF MID AND HIGH CLOUDS ACROSS THE FCST
AREA VIA THE LATEST VISIBLE AND IR TRENDS. THERE WILL LIKELY BE A
BRIEF BREAK BEFORE THE NEXT SHORT-WAVE ASSOCIATED WITH THE TROUGH
OF LOW PRESSURE APPROACHES FROM THE SOUTH AND WEST IN THE LATER
AFTERNOON. EVIDENCE OF THIS IMPULSE ARE THE SHOWERS AND
THUNDERSTORMS MOVING INTO WRN NY AND THE NIAGARA FRONTIER.
WE LOWERED THE CONVECTIVE CHANCES TO SLIGHT CHC VALUES PRIOR TO 6
PM DUE TO THE CANOPY OF CLOUDS AND THE LACK OF INSTABILITY. THE
LATEST SPC MESOANALYSIS SHOWS SBCAPE AND MLCAPE VALUES OF 200-500
J/KG OVER THE FCST AREA. THE MID LEVEL LAPSE RATES REMAIN WEAK
TOO. WE LOWERED MAX TEMPS A FEW MORE DEGREES...BUT KEPT SOME LOWER
80S NORTH AND EAST OF THE CAPITAL REGION WHERE A LITTLE MORE
SUNSHINE WILL OCCUR THROUGH THE CLOUDS.
THE CHANCE OF SHOWERS AND THUNDERSTORMS INCREASE ACROSS THE SRN
DACKS AND CNTRL BTWN 21Z-00Z BASED ON THE LATEST HRRR 3KM COLUMNAR
BASED REF PRODUCT WITH THE SHORT-WAVE.
PREVIOUS DISCUSSION...
EXPECT AN INCREASING CHANCE OF SHOWERS AND SOME THUNDERSTORMS
FROM LATER THIS MORNING INTO TONIGHT WITH MORE SHOWERS AND
THUNDERSTORMS WEDNESDAY INTO WEDNESDAY EVENING AS THE UPPER
TROUGH PASSES THROUGH THE REGION. AT THIS POINT IN TIME IT APPEARS
THE BEST CHANCE FOR THUNDERSTORMS WHICH MAY PRODUCE LOCALLY HEAVY
RAIN WOULD BE LATER THIS AFTERNOON INTO EARLY THIS EVENING WHEN
FIRST H10-H8 THETA E RIDGE AXIS PEAKS ACRS FA WITH SHOWALTER
INDICES AT OR SLIGHTLY BELOW ZERO...MLMUCAPES 300-1000 J/KG AND
PWATS ARND 1.5 INCHES. THE SECOND MOST ACTIVE PERIOD IS EXPECTED
TO BE WEDNESDAY AFTERNOON WITH SLIGHTLY HIGHER PWATS IN THE 1.5 TO
1.67 INCH RANGE...SHOWALTER INDICES SLIGHTLY MORE
NEGATIVE...STRONGER THETA E RIDGE AND MLMUCAPES GREATER BTWN 1500
AND 3000 J/KG.
THE CHANCE OF SEVERE WEATHER REMAINS UNCERTAIN AT THIS TIME AS
PLENTY OF CLOUD COVER DURING THE MID WEEK PERIOD MAY REDUCE
SURFACE HEATING AND CAPES AND H7-H5 LAPSE RATES RATHER
UNIMPRESSIVE UNTIL WEDNESDAY WHEN IT REACHES ABOVE 6 C/KM ACRS
PORTIONS OF THE FA. WEDNESDAY MAY HAVE THE BETTER CHANCE OF MORE
ORGANIZED CONVECTION WITH SLIGHTLY BETTER SHEAR AND 0-3 KM
HELICITY. AT THIS POINT WILL CONTINUE WITH PREVIOUS WORDING IN HWO
MENTIONING A FEW STORMS MAY HAVE DAMAGING WIND GUSTS ON WEDNESDAY.
EXPECT HIGHS TODAY IN THE MID 70S TO MID 80S AND ON WEDNESDAY IN
THE 70S TO LOWER 80S. LOWS TONIGHT ARE EXPECTED TO BE IN THE
UPPER 50S TO UPPER 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
ON WED NIGHT...EXPECT THE UPPER TROUGH AXIS TO SWING THROUGH THE
FA BY LATE EVENING WITH THE THREAT OF SHOWERS DIMINISHING DURING
THE SECOND HALF OF THE NIGHT AND LOWS IN THE MID 50S TO MID 60S.
ON THURSDAY RIDGING BUILDS ACRS THE FA AT THE SURFACE AND ALOFT
AND SLIDES EAST OF THE FA THURSDAY NIGHT PROVIDING DRY AND
SEASONABLE CONDITIONS. EXPECT HIGHS ON THURSDAY IN THE UPPER 70S TO
LOW TO MID 80S WITH LOWS THURSDAY NIGHT IN THE MID 50S TO LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
HAVE GENERALLY USED A 50/50 BLEND OF 18Z/13 HPC GUIDANCE AND 00Z/14
GMOS FOR THIS PORTION OF THE GRIDDED DATABASE...ALTHOUGH SKEWED
POPS/WEATHER TOWARD THE 00Z/14 ECMWF FOR LATE FRI-SAT EVENING.
FRIDAY...COLD FRONT SHOULD APPROACH FROM THE WEST IN THE AFTERNOON.
HOWEVER...MODELS VARY CONSIDERABLY ON TIMING...WITH THE 00Z/14 GFS
AND GEFS MOST PROGRESSIVE...AND THE 00Z/14 ECMWF SLOWEST. WILL
INDICATE CHC POPS...MAINLY IN THE AFTERNOON HOURS FOR SCATTERED
SHOWERS/TSTMS. EXPECT A WARM AND SOMEWHAT HUMID DAY...WITH MAX TEMPS
REACHING THE LOWER/MID 80S IN VALLEYS...AND 75-80 ACROSS HIGHER
TERRAIN. SHOULD CLOUDS/SHOWERS HOLD OFF UNTIL LATER IN THE
DAY...EVEN WARMER MAX TEMPS COULD OCCUR.
FRI NT-SAT NT...LOW DEGREE OF CONFIDENCE DURING THIS TIME
PERIOD...AS LATEST 00Z/14 ECMWF HAS TRENDED BACK TO A SLOWER
FROPA...WITH WAVE FORMATION ALONG THE BOUNDARY ACROSS THE NORTHERN
MID ATLANTIC STATES TRACKING NE INTO SOUTHERN NEW ENGLAND...IMPLYING
A RATHER WET SATURDAY...WHILE THE 00Z/14 GFS AND GEFS MEAN CONTINUE
WITH A MORE PROGRESSIVE SYSTEM...WITH DRY WEATHER FOR LATE FRI NT
INTO SAT. WILL SIDE CLOSER TO THE ECMWF...AND LINGER CHC POPS ACROSS
MUCH OF THE REGION FOR FRI NT AND EARLY SAT...AND THEN SLOWLY TAPER
POPS FROM NW TO SE SAT AFTERNOON/EVENING. EXPECT MIN TEMPS TO FALL
INTO THE LOWER 60S IN VALLEYS...AND 50S ACROSS HIGHER TERRAIN FOR
FRI NT/SAT AM...WITH MAX TEMPS SAT MAINLY IN THE 70S WITHIN
VALLEYS...AND 65-70 ACROSS HIGHER ELEVATIONS. HOWEVER...EVEN COOLER
MAXES COULD OCCUR IN VALLEY REGIONS SHOULD CLOUDS AND RAIN PERSIST
THROUGH THE AFTERNOON HOURS. SAT NT/SUN AM SHOULD BE COOLER...WITH
MINS FALLING INTO THE 50S IN MOST VALLEYS...AND 45-50 ACROSS HIGHER
ELEVATIONS.
SUN-MON...AT THIS TIME...WILL INDICATE FAIR AND SEASONABLY COOL
CONDITIONS...AS HIGH PRESSURE BUILDS IN FROM THE WEST. EXPECT MAX
TEMPS TO REACH 75-80 IN VALLEY AREAS...AND 70-75 ACROSS HIGHER
ELEVATIONS...WHILE OVERNIGHT MINS FALL INTO THE LOWER/MID 50S IN
MOST VALLEYS...AND 45-50 ACROSS HIGHER ELEVATIONS.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
WEAK LOW PRESSURE ACROSS THE OHIO VALLEY REGION WILL APPROACH FROM
THE SOUTHWEST LATER TODAY AND TONIGHT. THIS WILL BRING SOME SHOWERS
TO THE REGION INTO THIS EVENING.
ANY PATCHY GROUND FOG/LOW CLOUDS SHOULD GIVE WAY TO A THICKENING
HIGH AND MID LEVEL VFR CLOUD DECK. ISOLATED TO SCATTERED SHOWERS MAY
APPROACH KPOU AFTER 14Z/TUE...AND THE REMAINING TAF SITES AFTER
17Z/TUE...CONTINUING INTERMITTENTLY THROUGH TONIGHT. AT THIS
TIME...IT APPEARS THAT THE CHANCE FOR THUNDER IS QUITE LOW...AND
THEREFORE WILL KEEP MENTION OUT OF CURRENT SUITE OF TAFS. ISOLATED
TO SCATTERED SHOWERS WILL CONTINUE THROUGH TONIGHT. SOME MVFR VSBYS
WILL BE POSSIBLE LATER TONIGHT FROM THESE SHOWERS AND/OR BR. IN
ADDITION...SOME MVFR/IFR LOW CLOUDS MAY ADVECT NORTHWARD TOWARD
DAYBREAK...POSSIBLY AFFECTING KPOU AND KPSF...WITH A LOWER CHANCE
FOR KALB AND KGFL.
NEARLY CALM WINDS WILL BECOME SOUTHWEST TO SOUTH BY MID MORNING AT
5-10 KT...THEN WILL BECOME LIGHT/VARIABLE AROUND AND AFTER SUNSET.
OUTLOOK...
TUE NT-WED...VFR/MVFR. CHC SHRA/TSRA.
WED NT-THU...MAINLY VFR. NO SIG WX EXP AT THIS TIME. CHC MVFR/IFR
WITH BR/FG AT NIGHT.
FRI/SAT...VFR/MVFR. CHC SHRA/TSRA.
&&
.FIRE WEATHER...
LOW PRESSURE WILL APPROACH FROM THE LOWER GREAT LAKES REGION...AND
THE OHIO VALLEY TODAY WITH AN INCREASING THREAT OF SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON AND EVENING. THE UNSETTLED WEATHER
WILL CONTINUE INTO THE MID WEEK PERIOD...BEFORE HIGH PRESSURE
BRINGS FAIR AND DRY WEATHER FOR THURSDAY.
RELATIVE HUMIDITIES ARE EXPECTED TO DROP TO 45 TO 70 PERCENT
TODAY...RECOVER TO 80 TO 100 PERCENT TONIGHT...AND FALL TO 60 TO
80 PERCENT ON WEDNESDAY.
WINDS ARE EXPECTED TO BE SOUTH TO SOUTHWEST AT 5 TO 10 MPH
TODAY...SOUTHWEST TO WEST AROUND 5 MPH TONIGHT...AND SOUTHWEST AT
5 TO 10 MPH ON WEDNESDAY.
&&
.HYDROLOGY...
AT THIS TIME...NO PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THE
NEXT 5 DAYS.
MAINLY DRY WEATHER IS EXPECTED THROUGH EARLY THIS MORNING
FOLLOWED BY INCREASING SHOWERS AND SOME THUNDERSTORMS FOR THE MID
WEEK PERIOD. DRY WEATHER IS THEN EXPECTED FOR MUCH OF THE AREA
WEDNESDAY NIGHT THROUGH FRIDAY MORNING WITH MORE UNSETTLED WEATHER
FRIDAY AFTERNOON INTO SATURDAY. TOTAL RAINFALL AMOUNTS THROUGH
WEDNESDAY ARE GENERALLY EXPECTED TO RANGE FROM TWO THIRDS OF AN
INCH TO JUST UNDER AN INCH AND A HALF. HOWEVER...AREAS WHICH
RECEIVE MORE NUMEROUS THUNDERSTORMS CAN EXPECT LOCALIZED HIGHER
AMOUNTS.
DRY WEATHER RETURNS FOR THURSDAY BEFORE A COLD FRONT APPROACHES
FOR FRIDAY INTO THE WEEKEND WITH MORE SHOWERS AND THUNDERSTORMS.
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...WASULA
NEAR TERM...WASULA/11
SHORT TERM...11
LONG TERM...KL
AVIATION...KL/SNYDER
FIRE WEATHER...11
HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
727 PM EDT WED AUG 15 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL MOVE THROUGH THE REGION LATE TODAY AND
TONIGHT...AND STALL JUST TO OUR SOUTH THURSDAY. DRIER AIR ENTERING
THE REGION BEHIND THE FRONT IS EXPECTED TO PROVIDE FAIR WEATHER
THURSDAY. MOISTURE RETURN WILL GRADUALLY RESUME FRIDAY AHEAD OF
ANOTHER FRONT THAT WILL DROP INTO THE REGION SATURDAY...AND THEN
STALL IN PLACE INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THIS AFTERNOON...SHORT WAVE IN UPSTATE MOVING EAST APPEARS TO
WEAKEN AS IT MOVES OVER NORTHERN PORTION OF FORECAST AREA. THERE
IS CURRENTLY A NARROW BAND OF SHOWERS ENTERING THE NORTHERN
PORTION OF THE FORECAST AREA AS A WEAK COLD FRONT MOVES WEST TO
EAST ACROSS THE AREA BY LATE THIS AFTERNOON. BOTH RUC13 AND LOCAL
4 KM WRF KEEP PRECIP CONFINED TO THE NORTH AND EAST PORTIONS OF
REGION. HOWEVER...DECIDED TO GO AT LEAST 20 PERCENT CHANCE MOST
LOCATIONS. IN ADDITION...ADDED A 30 PERCENT CHANCE NORTH OF CAE
FOR A 2-3 HOUR PERIOD. THIS MATCHES UP WELL WITH GSP. SPC EARLIER
HAD A SLIGHT RISK OF SEVERE STORMS IN THE EASTERN PART OF THE
FORECAST AREA BUT HAS SINCE MOVED IT WELL TO THE EAST. MODELS KEEP
ENERGY MAINLY TO THE NORTH. MOST UNSTABLE LOCATIONS WILL BE TO THE
EAST. CLOUDS HAVE BROKEN UP AS NAM BUFR SHOWS DRIER AIR MOVING IN.
PW VALUES DROP BELOW 1.5 INCHES. STILL SUNSHINE IN THE EAST MAY
LEAD TO STRONGER LOW LEVEL LAPSE RATES AND HIGHER CAPES. HIGH
READINGS MAINLY IN LOWER 90S STILL OK.
TONIGHT...A TRAILING SHORT WAVE IS EXPECTED TO MOVE THROUGH TO
THE SOUTHEAST TOWARD THE COAST BY THIS EVENING. HAVE SLIGHT CHANCE
EAST OF CAE UNTIL ABOUT 02Z. THINK ATMOSPHERE WILL BE TOO STABLE
FOR STRONG STORMS. THE ACTIVITY SHOULD DIMINISH AS THE COLD FROM
MOVES INTO THE LOW COUNTRY. IN GOOD AGREEMENT WITH MOS LOW
TEMPERATURES IN THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
UPPER RIDGE WILL CONTINUE OVER THE WESTERN CONUS...AS CLOSED UPPER
LOW REMAINS NEARLY STATIONARY OVER ONTARIO WITH TROUGHINESS
EXTENDING SOUTH INTO THE SE US. SURFACE FRONT WILL PUSH JUST TO THE
SOUTH OF OUR FORECAST AREA THURSDAY...WITH WEAK SURFACE HIGH
PRESSURE OVER OUR REGION. DRIER AIR WILL PREVENT CONVECTION. THERE
ARE SOME INDICATIONS OF POSSIBLE CONVECTION ALONG THE FRONT LATE
THU AFTN OR EVE JUST TO OUR SOUTH...BUT CURRENT INDICATIONS ARE
THAT IT WILL STAY JUST SOUTH OF OUR FA. NEXT WEAK FRONT AND WEAK
UPPER DISTURBANCE TO APPROACH FROM THE NW FRIDAY...WITH JUST
ENOUGH MOISTURE INCREASE FROM THE SOUTH AHEAD OF IT TO WARRANT
SLIGHT CHANCE POPS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
LITTLE CHANGE IN THE UPPER PATTERN...WITH RIDGE WEST AND TROUGH EAST
AS UPPER LOW IS PROGGED TO CONTINUE SPINNING OVER ONTARIO/HUDSON BAY
REGION. A SERIES OF UPPER DISTURBANCES ROTATING AROUND THE LOW WILL
MOVE SE INTO THE EASTERN CONUS...WITH TROUGH DEEPENING SLIGHTLY WITH
TIME. GFS/ECMWF BRING SURFACE FRONT INTO THE REGION SATURDAY AND
STALL IT OVER OUR REGION INTO EARLY NEXT WEEK. PLENTIFUL ATMOSPHERIC
MOISTURE AND A SERIES OF UPPER DISTURBANCES WILL PROVIDE AT LEAST
CHANCE POPS THROUGH THE PERIOD. GENERALLY ACCEPTED HPC GUIDANCE.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
EXPECT MAINLY VFR CONDITIONS DURING THE TAF PERIOD. MOST OF THE
UPPER-LEVEL LIFT HAS REMAINED NORTH OF THE FORECAST AREA. EXPECT
ANY THUNDERSTORMS THIS EVENING WILL REMAIN ISOLATED WITH THE
CHANCE TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME.
A RELATIVELY DRY AIR MASS AND A LITTLE MIXING SHOULD LIMIT FOG.
HOWEVER...FOG MAY OCCUR DURING THE EARLY MORNING HOURS BECAUSE OF
SOME CONVERGENCE ALONG THE WEAK FRONT. THE FOG POTENTIAL APPEARS
GREATER AT THE RIVER VALLEY TERMINALS OF AGS AND OGB. USED THE GFS
LAMP AND FORECASTED A PERIOD OF MVFR FOG. HEATING AND MIXING
SHOULD HELP DISSIPATE ANY FOG BY 14Z.
EXTENDED AVIATION OUTLOOK...EXPECT RESTRICTIONS IN SCATTERED
THUNDERSTORMS AHEAD OF A COLD FRONT FRIDAY AND FRIDAY NIGHT.
THE FRONT WILL LIKELY STALL NEAR THE AREA SATURDAY AND REMAIN
THROUGH MONDAY. WIDESPREAD LOW CLOUDINESS AND FOG MAY OCCUR
ESPECIALLY DURING THE EARLY MORNING HOURS BECAUSE OF MOISTURE
ASSOCIATED WITH THE FRONT. THERE SHOULD ALSO BE SCATTERED
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
716 PM EDT WED AUG 15 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL MOVE THROUGH THE REGION LATE TODAY AND
TONIGHT...AND STALL JUST TO OUR SOUTH THURSDAY. DRIER AIR ENTERING
THE REGION BEHIND THE FRONT IS EXPECTED TO PROVIDE FAIR WEATHER
THURSDAY. MOISTURE RETURN WILL GRADUALLY RESUME FRIDAY AHEAD OF
ANOTHER FRONT THAT WILL DROP INTO THE REGION SATURDAY...AND THEN
STALL IN PLACE INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...SHORT WAVE IN UPSTATE MOVING EAST APPEARS TO
WEAKEN AS IT MOVES OVER NORTHERN PORTION OF FORECAST AREA. THERE
IS CURRENTLY A NARROW BAND OF SHOWERS ENTERING THE NORTHERN
PORTION OF THE FORECAST AREA AS A WEAK COLD FRONT MOVES WEST TO
EAST ACROSS THE AREA BY LATE THIS AFTERNOON. BOTH RUC13 AND LOCAL
4 KM WRF KEEP PRECIP CONFINED TO THE NORTH AND EAST PORTIONS OF
REGION. HOWEVER...DECIDED TO GO AT LEAST 20 PERCENT CHANCE MOST
LOCATIONS. IN ADDITION...ADDED A 30 PERCENT CHANCE NORTH OF CAE
FOR A 2-3 HOUR PERIOD. THIS MATCHES UP WELL WITH GSP. SPC EARLIER
HAD A SLIGHT RISK OF SEVERE STORMS IN THE EASTERN PART OF THE
FORECAST AREA BUT HAS SINCE MOVED IT WELL TO THE EAST. MODELS KEEP
ENERGY MAINLY TO THE NORTH. MOST UNSTABLE LOCATIONS WILL BE TO THE
EAST. CLOUDS HAVE BROKEN UP AS NAM BUFR SHOWS DRIER AIR MOVING IN.
PW VALUES DROP BELOW 1.5 INCHES. STILL SUNSHINE IN THE EAST MAY
LEAD TO STRONGER LOW LEVEL LAPSE RATES AND HIGHER CAPES. HIGH
READINGS MAINLY IN LOWER 90S STILL OK.
TONIGHT...A TRAILING SHORT WAVE IS EXPECTED TO MOVE THROUGH TO
THE SOUTHEAST TOWARD THE COAST BY THIS EVENING. HAVE SLIGHT CHANCE
EAST OF CAE UNTIL ABOUT 02Z. THINK ATMOSPHERE WILL BE TOO STABLE
FOR STRONG STORMS. THE ACTIVITY SHOULD DIMINISH AS THE COLD FROM
MOVES INTO THE LOW COUNTRY. IN GOOD AGREEMENT WITH MOS LOW
TEMPERATURES IN THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
UPPER RIDGE WILL CONTINUE OVER THE WESTERN CONUS...AS CLOSED UPPER
LOW REMAINS NEARLY STATIONARY OVER ONTARIO WITH TROUGHINESS
EXTENDING SOUTH INTO THE SE US. SURFACE FRONT WILL PUSH JUST TO THE
SOUTH OF OUR FORECAST AREA THURSDAY...WITH WEAK SURFACE HIGH
PRESSURE OVER OUR REGION. DRIER AIR WILL PREVENT CONVECTION. THERE
ARE SOME INDICATIONS OF POSSIBLE CONVECTION ALONG THE FRONT LATE
THU AFTN OR EVE JUST TO OUR SOUTH...BUT CURRENT INDICATIONS ARE
THAT IT WILL STAY JUST SOUTH OF OUR FA. NEXT WEAK FRONT AND WEAK
UPPER DISTURBANCE TO APPROACH FROM THE NW FRIDAY...WITH JUST
ENOUGH MOISTURE INCREASE FROM THE SOUTH AHEAD OF IT TO WARRANT
SLIGHT CHANCE POPS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
LITTLE CHANGE IN THE UPPER PATTERN...WITH RIDGE WEST AND TROUGH EAST
AS UPPER LOW IS PROGGED TO CONTINUE SPINNING OVER ONTARIO/HUDSON BAY
REGION. A SERIES OF UPPER DISTURBANCES ROTATING AROUND THE LOW WILL
MOVE SE INTO THE EASTERN CONUS...WITH TROUGH DEEPENING SLIGHTLY WITH
TIME. GFS/ECMWF BRING SURFACE FRONT INTO THE REGION SATURDAY AND
STALL IT OVER OUR REGION INTO EARLY NEXT WEEK. PLENTIFUL ATMOSPHERIC
MOISTURE AND A SERIES OF UPPER DISTURBANCES WILL PROVIDE AT LEAST
CHANCE POPS THROUGH THE PERIOD. GENERALLY ACCEPTED HPC GUIDANCE.
&&
.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
EXPECT MAINLY VFR CONDITIONS DURING THE TAF PERIOD. MOST OF THE
UPPER-LEVEL LIFT HAS REMAINED NORTH OF THE FORECAST AREA. EXPECT
ANY THUNDERSTORMS THIS EVENING WILL REMAIN ISOLATED WITH THE
CHANCE TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME.
A RELATIVELY DRY AIR MASS AND A LITTLE MIXING SHOULD LIMIT FOG.
HOWEVER...FOG MAY OCCUR DURING THE EARLY MORNING HOURS BECAUSE OF
SOME CONVERGENCE ALONG THE WEAK FRONT. THE FOG POTENTIAL APPEARS
GREATER AT THE RIVER VALLEY TERMINALS OF AGS AND OGB. USED THE GFS
LAMP AND FORECASTED A PERIOD OF MVFR FOG. HEATING AND MIXING
SHOULD HELP DISSIPATE ANY FOG AFTER 14Z.
EXTENDED AVIATION OUTLOOK...EXPECT RESTRICTIONS IN SCATTERED
THUNDERSTORMS AHEAD OF A COLD FRONT FRIDAY AND FRIDAY NIGHT.
THE FRONT WILL LIKELY STALL NEAR THE AREA SATURDAY AND REMAIN
THROUGH MONDAY. WIDESPREAD LOW CLOUDINESS AND FOG MAY OCCUR
ESPECIALLY DURING THE EARLY MORNING HOURS BECAUSE OF MOISTURE
ASSOCIATED WITH THE FRONT. THERE SHOULD ALSO BE SCATTERED
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
147 PM EDT TUE AUG 14 2012
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
/ISSUED AT 324 AM EDT TUE AUG 14 2012/
UPPER SHORT WAVE ENERGY EMBEDDED IN A LONG WAVE TROUGH THAT
STRETCHES FROM THE GREAT LAKES TO THE NORTH CENTRAL GULF REGION...
HAS SPARKED CONTINUED CONVECTION ACROSS EASTERN AL AND INTO NW AND
WEST CENTRAL GA EARLY THIS MORNING. GFS...NAM...RUC AND HRRR MODELS
HOLD THIS CONVECTION TOGETHER AND BRING AT LEAST SCATTERED SHOWERS
INTO THE ATLANTA METRO AREA AROUND 8-10 AM THIS MORNING. HOWEVER...
CANNOT RULE OUT AN ISOLATED RUMBLE OF THUNDER DURING THE MORNING
HOURS. EXPECT THIS INITIAL CONVECTIVE ACTIVITY TO PUSH EAST AND
SOUTH BUT WEAKEN THROUGH THE MORNING HOURS. THEN A COLD FRONT...
CURRENTLY ANALYZED ACROSS WESTERN TN... WILL PUSH INTO NW GA LATER
THIS AFTERNOON. THIS FRONT WILL PROVIDE THE SPARK FOR A SECOND ROUND
OF CONVECTION... THAT BEGINS ACROSS NORTH GA... THEN SPREADS SOUTH
ACROSS THE ATLANTA AREA DURING THE LATE AFTERNOON TO EARLY EVENING
HOURS. MODEST INSTABILITIES OF 1500-2500 CAPE AND LACK OF STRONG
UPPER SUPPORT SUGGEST THE ASSOCIATED THUNDERSTORMS SHOULD REMAIN
BELOW SEVERE LIMITS... HOWEVER SMALL HAIL AND WIND GUSTS TO 45 MPH
ARE LIKELY WITH THE STRONGER STORMS. EXPECT THESE STORMS TO MOVE
FAST ENOUGH TO THE SOUTH AND SOUTHEAST TO LESSON ANY LOCALIZED FLOOD
THREAT. THE NAM AND GFS ARE IN GOOD AGREEMENT WITH THE FRONT... AND
ARE SLOW PUSHING THE FRONT SOUTH... NOT CLEARING THE ATLANTA METRO
AREA UNTIL SOMETIME WEDNESDAY MORNING. BOTH MODELS STALL THE FRONT
ACROSS CENTRAL GA ON WEDNESDAY... WARRANTING A SLIGHT CHANCE OF
THUNDER THERE THROUGH WEDNESDAY AFTERNOON. OTHERWISE... TOOK A MAV
AND MET BLEND FOR HIGHS AND LOWS THROUGH THE SHORT TERM... WITH
COOLER LOWS EXPECTED ACROSS NORTH GA LATE TONIGHT BEHIND THE FRONT.
DESPITE THE DRIER/COOLER AIR SPREADING INTO THE AREA ON WEDNESDAY
BEHIND THE FRONT... EXPECT DAYTIME HIGHS TO STILL CLIMB INTO THE
UPPER 80S OR LOWER 90S FOR MOST AREAS AS GUIDANCE INDICATES.
39
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED AT 324 AM EDT TUE AUG 14 2012/
EASTERN U.S. REMAINS UNDER THE INFLUENCE OF THE LONG WAVE UPPER
TROUGH THROUGH THE EXTENDED FORECAST PERIOD. TROUGH STARTS OUT
RATHER FLAT AT MIDWEEK BEHIND AN EXITING SHORT WAVE...BUT SHARPENS UP
AND DEEPENS AS WE APPROACH THE WEEKEND. SHOULD SEE ANOTHER MOSTLY DRY
AND MILD BREAK WEDNESDAY NIGHT AND THURSDAY WITH PRECIPITATION
CHANCES INCREASING ONCE AGAIN AS WE HEAD INTO THE UPCOMING WEEKEND.
DEEP UPPER TROUGH DRIVES ANOTHER FAIRLY STOUT COLD FRONT INTO THE
STATE FOR THE WEEKEND. HARD TO TIME THE BEST PERIODS FOR
PRECIPITATION THROUGH THE WEEKEND AS THE FRONT LINGERS AND SHORT
WAVES ROTATE THROUGH THE LONG WAVE TROUGH SO I HAVE KEPT POPS IN THE
CHANCE RANGE FRIDAY THROUGH SUNDAY. SHOULD START TO SEE A BIT OF
BREAK BY MONDAY AS THE FRONT SINKS SOUTH ALLOWING DRIER AIR TO FILTER
IN AND THE UPPER TROUGH AXIS SHIFTS EAST OF THE STATE.
20
&&
.AVIATION...
18Z UPDATE...
VISIBLE SATELLITE LOOP SHOWS A BREAK IN THE CLOUDS OVER ATL WITH
SCATTERED TO BROKEN LOW AND MID CLOUDS OVER THE REMAINDER OF THE TAF
SITES. MORNING MODEL RUNS STILL SHOW ENOUGH MOISTURE AND INSTABILITY
AVAILABLE IN ADVANCE OF THE COLD FRONT TO COMBINE WITH THE DIURNAL
HEATING FOR TSTM DEVELOPMENT. BEST TIME PERIOD FOR CONVECTION WILL
BE 20-24Z. DEPENDING ON THE AMOUNT OF RAINFALL...EXPECT CIGS TO
LOWER TO IFR FROM 09-14Z AT MOST LOCATIONS. DRIER AIR WILL MOVE IN
WITH A NORTHWEST FLOW DURING THE REMAINDER OF WEDNESDAY.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON ALL ELEMENTS.
16
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 70 91 67 / 50 30 20 10
ATLANTA 87 70 89 70 / 50 30 20 10
BLAIRSVILLE 82 65 83 60 / 40 30 20 10
CARTERSVILLE 87 67 88 62 / 40 30 20 10
COLUMBUS 90 72 93 72 / 50 30 20 10
GAINESVILLE 85 69 88 67 / 50 30 20 10
MACON 92 71 92 71 / 50 30 20 10
ROME 87 66 90 62 / 50 30 10 10
PEACHTREE CITY 87 68 89 64 / 50 30 20 5
VIDALIA 92 72 92 73 / 50 30 20 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...16
LONG TERM....20
AVIATION...16
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1248 PM EDT TUE AUG 14 2012
.SYNOPSIS...
AN UPPER-LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL APPROACH
THE AREA FROM THE WEST TODAY. THE FRONT WILL BECOME DIFFUSE IN THE
FORECAST AREA WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
SCATTERED SHOWERS WERE IN THE FORECAST AREA EARLY THIS AFTERNOON. THE
SHOWERS WERE ASSOCIATED WITH CONVERGENCE AHEAD OF THE COLD FRONT
AND A MID-LEVEL SHORTWAVE TROUGH. COVERAGE HAS BEEN LIMITED BY THE
DRY AIR MASS IN PLACE AHEAD OF THE SHOWERS. THE LATEST RAP SHOWS
THE SHORTWAVE TROUGH WILL BE SHIFTING EAST OF THE FORECAST AREA
LATER THIS AFTERNOON...BUT INCREASED LOW-LEVEL MOISTURE AHEAD OF
THE FRONT AND DIURNAL HEATING SHOULD RESULT IN SCATTERED
THUNDERSTORMS. CLOUDINESS AND THE UPPER-LEVEL LIFT SHIFTING EAST
OF THE FORECAST AREA DURING THE AFTERNOON SHOULD LIMIT
INSTABILITY. THE NAM INDICATES MAINLY WEAK INSTABILITY WITH
AFTERNOON SURFACE LI/S NEAR -5. THE ACTIVITY COULD LINGER INTO THE
EVENING AND POSSIBLY THE OVERNIGHT HOURS BECAUSE OF CONTINUED
CONVERGENCE ASSOCIATED WITH THE WEAK FRONT AND POSSIBLY ANOTHER
MID-LEVEL SHORTWAVE TROUGH. HOWEVER...WE HAVE FORECASTED LOW POPS
BECAUSE OF THE LOSS OF HEATING AND THIS IS ALSO SUPPORTED BY THE
NAM AND GFS MOS GUIDANCE. EXPECT TEMPERATURES NEAR CLIMATOLOGY
WITH HIGHS TODAY NEAR 90 AND LOWS TONIGHT IN THE LOWER 70S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ON WEDNESDAY...THE UPPER TROUGH WILL CONTINUE TO MOVE SLOWLY EAST
ACROSS THE REGION. AT THE SURFACE...MODELS INDICATE THAT THE FRONT
WILL PUSH INTO THE FORECAST AREA AND BECOME DIFFUSE. THE SPC HAS
THE AREA IN A SEE TEXT WITH A MENTION THAT THIS AREA COULD BE
UPGRADED TO A SLIGHT RISK. MODEL TIME SECTIONS SHOW THE AIR MASS
ON WEDNESDAY WILL BECOME MODERATELY UNSTABLE WITH CAPE VALUES
APPROACHING 2000 J/KG...TT AROUND 50 AND LI/S BETWEEN -3 AND -6.
ALSO PRECIPITABLE WATER VALUES WILL BE AROUND 1.8 INCHES. A FEW
OF THE STORMS COULD BECOME STRONG WITH GUSTY WINDS AND LOCALLY
HEAVY RAIN. THE STORMS SHOULD BE MOVING ENOUGH TO PREVENT ANY
SIGNIFICANT FLOODING. THE BEST CHANCE FOR THUNDERSTORMS WILL BE
ACROSS THE EASTERN MIDLANDS ALONG AND AHEAD OF THE FRONTAL
BOUNDARY. BY WEDNESDAY NIGHT INTO THURSDAY...THE TROUGH AXIS WILL
MOVE EAST OF THE AREA. WEAK HIGH PRESSURE IS EXPECTED TO BUILD
INTO THE REGION FOR THURSDAY/THU NIGHT. GUIDANCE AND LOCAL NUMBERS
REASONABLY CLOSE THROUGH THE PERIOD AND HAVE STAYED NEAR CONSENSUS
FOR TEMPERATURES AND POPS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
UPPER FLOW BECOMES MORE ZONAL FRIDAY. A LONG-WAVE TROUGH THEN
BEGINS TO DEEPEN WITH ITS AXIS JUST TO THE WEST OF THE APPALACHIAN
MOUNTAINS SATURDAY THROUGH MONDAY. AN INCREASE IN LOW-LEVEL
MOISTURE IS EXPECTED TO YIELD A 20 TO 40 PERCENT CHANCE OF MAINLY
AFTERNOON AND EVENING CONVECTIVE ACTIVITY FRIDAY THROUGH MONDAY.
MAX TEMPERATURES AROUND 90 SHOULD BE THE RULE FRIDAY...BUT COOLING
DOWN SLIGHTLY INTO THE WEEKEND AS THE TROUGH DEVELOPS ACROSS THE
EASTERN HALF OF THE COUNTRY. MORE CLOUDS SATURDAY THROUGH MONDAY
WILL PROBABLY KEEP HIGHS IN THE MIDDLE/UPPER 80S. OVERNIGHT LOWS
IN THE MIDDLE/UPPER 60S TO LOWER 70S FOR MOST OF THE PERIOD.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
UPPER TROUGH SWINGING ACROSS THE TENNESSEE VALLEY RESULTING IN
CONVECTION OVER GEORGIA WITH VFR CIGS AROUND 6000 FT AHEAD OF THE
CONVECTION OVERSPREADING THE TERMINALS. NOT EXPECTING MUCH IN THE
WAY OF VSBY RESTRICTIONS AT THE TAF SITES WITH THIS CONVECTION.
A COLD FRONT WILL PUSH INTO THE AREA LATER THIS AFTERNOON BUT DEEP
MOISTURE IS LIMITED AS WELL AS INSTABILITY SO CONFIDENCE IS LOW FOR
TIMING CONVECTION AND COVERAGE SHOULD BE WIDELY SCATTERED. EXPECT
CUMULUS ALONG WITH A HIGHER CEILING DUE TO UPSTREAM CONVECTIVE
DEBRIS ADVECTING EASTWARD. WINDS WILL GENERALLY BE CALM THROUGH
SUNRISE THEN INCREASE TO AROUND 10 MPH FROM THE SOUTHWEST...THEN
BECOME LIGHT AFTER SUNSET.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1038 AM EDT TUE AUG 14 2012
.SYNOPSIS...
AN UPPER-LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL APPROACH
THE AREA FROM THE WEST TODAY. THE FRONT WILL BECOME DIFFUSE IN THE
FORECAST AREA WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
EXPECT A CONTINUED WEAKENING TREND WITH THE SHOWERS MOVING INTO
THE AREA FROM THE WEST THIS MORNING BECAUSE OF THE DRY AIR MASS IN
PLACE. THESE SHOWERS ARE ASSOCIATED WITH CONVERGENCE AHEAD OF THE
COLD FRONT AND A MID-LEVEL SHORTWAVE TROUGH. THE LATEST RAP SHOWS
THE SHORTWAVE TROUGH WILL BE SHIFTING EAST OF THE FORECAST AREA
THIS AFTERNOON...BUT INCREASED LOW-LEVEL MOISTURE AHEAD OF THE
FRONT AND DIURNAL HEATING SHOULD RESULT IN SCATTERED
THUNDERSTORMS. CLOUDINESS AND THE UPPER-LEVEL LIFT SHIFTING EAST
OF THE FORECAST AREA DURING THE AFTERNOON SHOULD LIMIT
INSTABILITY. THE NAM INDICATES MAINLY WEAK INSTABILITY WITH
AFTERNOON SURFACE LI/S NEAR -5. THE ACTIVITY COULD LINGER INTO
THE EVENING AND POSSIBLY THE OVERNIGHT HOURS BECAUSE OF CONTINUED
CONVERGENCE ASSOCIATED WITH THE WEAK FRONT AND POSSIBLY ANOTHER
MID-LEVEL SHORTWAVE TROUGH. HOWEVER...WE HAVE FORECASTED LOW POPS
BECAUSE OF THE LOSS OF HEATING AND THIS IS ALSO SUPPORTED BY THE
NAM AND GFS MOS GUIDANCE. EXPECT TEMPERATURES NEAR CLIMATOLOGY
WITH HIGHS TODAY NEAR 90 AND LOWS TONIGHT IN THE LOWER 70S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ON WEDNESDAY...THE UPPER TROUGH WILL CONTINUE TO MOVE SLOWLY EAST
ACROSS THE REGION. AT THE SURFACE...MODELS INDICATE THAT THE FRONT
WILL PUSH INTO THE FORECAST AREA AND BECOME DIFFUSE. THE SPC HAS
THE AREA IN A SEE TEXT WITH A MENTION THAT THIS AREA COULD BE
UPGRADED TO A SLIGHT RISK. MODEL TIME SECTIONS SHOW THE AIR MASS
ON WEDNESDAY WILL BECOME MODERATELY UNSTABLE WITH CAPE VALUES
APPROACHING 2000 J/KG...TT AROUND 50 AND LI/S BETWEEN -3 AND -6.
ALSO PRECIPITABLE WATER VALUES WILL BE AROUND 1.8 INCHES. A FEW
OF THE STORMS COULD BECOME STRONG WITH GUSTY WINDS AND LOCALLY
HEAVY RAIN. THE STORMS SHOULD BE MOVING ENOUGH TO PREVENT ANY
SIGNIFICANT FLOODING. THE BEST CHANCE FOR THUNDERSTORMS WILL BE
ACROSS THE EASTERN MIDLANDS ALONG AND AHEAD OF THE FRONTAL
BOUNDARY. BY WEDNESDAY NIGHT INTO THURSDAY...THE TROUGH AXIS WILL
MOVE EAST OF THE AREA. WEAK HIGH PRESSURE IS EXPECTED TO BUILD
INTO THE REGION FOR THURSDAY/THU NIGHT. GUIDANCE AND LOCAL NUMBERS
REASONABLY CLOSE THROUGH THE PERIOD AND HAVE STAYED NEAR CONSENSUS
FOR TEMPERATURES AND POPS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
UPPER FLOW BECOMES MORE ZONAL FRIDAY. A LONG-WAVE TROUGH THEN
BEGINS TO DEEPEN WITH ITS AXIS JUST TO THE WEST OF THE APPALACHIAN
MOUNTAINS SATURDAY THROUGH MONDAY. AN INCREASE IN LOW-LEVEL
MOISTURE IS EXPECTED TO YIELD A 20 TO 40 PERCENT CHANCE OF MAINLY
AFTERNOON AND EVENING CONVECTIVE ACTIVITY FRIDAY THROUGH MONDAY.
MAX TEMPERATURES AROUND 90 SHOULD BE THE RULE FRIDAY...BUT COOLING
DOWN SLIGHTLY INTO THE WEEKEND AS THE TROUGH DEVELOPS ACROSS THE
EASTERN HALF OF THE COUNTRY. MORE CLOUDS SATURDAY THROUGH MONDAY
WILL PROBABLY KEEP HIGHS IN THE MIDDLE/UPPER 80S. OVERNIGHT LOWS
IN THE MIDDLE/UPPER 60S TO LOWER 70S FOR MOST OF THE PERIOD.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
UPPER TROUGH SWINGING ACROSS THE TENNESSEE VALLEY RESULTING IN
CONVECTION OVER GEORGIA WITH VFR CIGS AROUND 6000 FT AHEAD OF THE
CONVECTION OVERSPREADING THE TERMINALS. SOME MVFR VSBYS IN FOG
POSSIBLE AT OGB 12Z-13Z. WILL INCLUDE VCSH AGS/DNL 13Z-15Z AND
CAE/CUB 15Z-17Z ALTHOUGH DO NOT EXPECT RESTRICTIONS.
A COLD FRONT WILL PUSH INTO THE AREA LATER THIS AFTERNOON BUT DEEP
MOISTURE IS LIMITED AS WELL AS INSTABILITY SO CONFIDENCE IS LOW FOR
TIMING CONVECTION AND COVERAGE SHOULD BE WIDELY SCATTERED. EXPECT
CUMULUS ALONG WITH A HIGHER CEILING DUE TO UPSTREAM CONVECTIVE
DEBRIS ADVECTING EASTWARD. WINDS WILL GENERALLY BE CALM THROUGH
SUNRISE THEN INCREASE TO AROUND 10 MPH FROM THE SOUTHWEST...THEN
BECOME LIGHT AFTER SUNSET.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
800 AM EDT TUE AUG 14 2012
.SYNOPSIS...
AN UPPER-LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL APPROACH
THE AREA FROM THE WEST TODAY. THE FRONT WILL BECOME DIFFUSE IN THE
FORECAST AREA WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
EXPECT A CONTINUED WEAKENING TREND WITH THE SHOWERS MOVING INTO
THE AREA FROM THE WEST THIS MORNING BECAUSE OF THE DRY AIR MASS IN
PLACE. THESE SHOWERS ARE ASSOCIATED WITH CONVERGENCE AHEAD OF THE
COLD FRONT AND A MID-LEVEL SHORTWAVE TROUGH. THE LATEST RAP SHOWS
THE SHORTWAVE TROUGH WILL BE SHIFTING EAST OF THE FORECAST AREA
THIS AFTERNOON...BUT INCREASED LOW-LEVEL MOISTURE AHEAD OF THE
FRONT AND DIURNAL HEATING SHOULD RESULT IN SCATTERED
THUNDERSTORMS. CLOUDINESS AND THE UPPER-LEVEL LIFT SHIFTING EAST
OF THE FORECAST AREA DURING THE AFTERNOON SHOULD LIMIT
INSTABILITY. THE NAM INDICATES MAINLY WEAK INSTABILITY WITH
AFTERNOON SURFACE LI/S NEAR -5. THE THREAT OF SEVERE WEATHER
APPEARS LOW. THE ACTIVITY COULD LINGER INTO THE EVENING AND
POSSIBLY THE OVERNIGHT HOURS BECAUSE OF CONTINUED CONVERGENCE
ASSOCIATED WITH THE WEAK FRONT AND POSSIBLY ANOTHER MID-LEVEL
SHORTWAVE TROUGH. HOWEVER...WE HAVE FORECASTED LOW POPS BECAUSE OF
THE LOSS OF HEATING AND THIS IS ALSO SUPPORTED BY THE NAM AND GFS
MOS GUIDANCE. EXPECT TEMPERATURES NEAR CLIMATOLOGY WITH HIGHS
TODAY NEAR 90 AND LOWS TONIGHT IN THE LOWER 70S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ON WEDNESDAY...THE UPPER TROUGH WILL CONTINUE TO MOVE SLOWLY EAST
ACROSS THE REGION. AT THE SURFACE...MODELS INDICATE THAT THE FRONT
WILL PUSH INTO THE FORECAST AREA AND BECOME DIFFUSE. THE SPC HAS
THE AREA IN A SEE TEXT WITH A MENTION THAT THIS AREA COULD BE
UPGRADED TO A SLIGHT RISK. MODEL TIME SECTIONS SHOW THE AIR MASS
ON WEDNESDAY WILL BECOME MODERATELY UNSTABLE WITH CAPE VALUES
APPROACHING 2000 J/KG...TT AROUND 50 AND LI/S BETWEEN -3 AND -6.
ALSO PRECIPITABLE WATER VALUES WILL BE AROUND 1.8 INCHES. A FEW
OF THE STORMS COULD BECOME STRONG WITH GUSTY WINDS AND LOCALLY
HEAVY RAIN. THE STORMS SHOULD BE MOVING ENOUGH TO PREVENT ANY
SIGNIFICANT FLOODING. THE BEST CHANCE FOR THUNDERSTORMS WILL BE
ACROSS THE EASTERN MIDLANDS ALONG AND AHEAD OF THE FRONTAL
BOUNDARY. BY WEDNESDAY NIGHT INTO THURSDAY...THE TROUGH AXIS WILL
MOVE EAST OF THE AREA. WEAK HIGH PRESSURE IS EXPECTED TO BUILD
INTO THE REGION FOR THURSDAY/THU NIGHT. GUIDANCE AND LOCAL NUMBERS
REASONABLY CLOSE THROUGH THE PERIOD AND HAVE STAYED NEAR CONSENSUS
FOR TEMPERATURES AND POPS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
UPPER FLOW BECOMES MORE ZONAL FRIDAY. A LONG-WAVE TROUGH THEN
BEGINS TO DEEPEN WITH ITS AXIS JUST TO THE WEST OF THE APPALACHIAN
MOUNTAINS SATURDAY THROUGH MONDAY. AN INCREASE IN LOW-LEVEL
MOISTURE IS EXPECTED TO YIELD A 20 TO 40 PERCENT CHANCE OF MAINLY
AFTERNOON AND EVENING CONVECTIVE ACTIVITY FRIDAY THROUGH MONDAY.
MAX TEMPERATURES AROUND 90 SHOULD BE THE RULE FRIDAY...BUT COOLING
DOWN SLIGHTLY INTO THE WEEKEND AS THE TROUGH DEVELOPS ACROSS THE
EASTERN HALF OF THE COUNTRY. MORE CLOUDS SATURDAY THROUGH MONDAY
WILL PROBABLY KEEP HIGHS IN THE MIDDLE/UPPER 80S. OVERNIGHT LOWS
IN THE MIDDLE/UPPER 60S TO LOWER 70S FOR MOST OF THE PERIOD.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
UPPER TROUGH SWINGING ACROSS THE TENNESSEE VALLEY RESULTING IN
CONVECTION OVER GEORGIA WITH VFR CIGS AROUND 6000 FT AHEAD OF THE
CONVECTION OVERSPREADING THE TERMINALS. SOME MVFR VSBYS IN FOG
POSSIBLE AT OGB 12Z-13Z. WILL INCLUDE VCSH AGS/DNL 13Z-15Z AND
CAE/CUB 15Z-17Z ALTHOUGH DO NOT EXPECT RESTRICTIONS.
A COLD FRONT WILL PUSH INTO THE AREA LATER THIS AFTERNOON BUT DEEP
MOISTURE IS LIMITED AS WELL AS INSTABILITY SO CONFIDENCE IS LOW FOR
TIMING CONVECTION AND COVERAGE SHOULD BE WIDELY SCATTERED. EXPECT
CUMULUS ALONG WITH A HIGHER CEILING DUE TO UPSTREAM CONVECTIVE
DEBRIS ADVECTING EASTWARD. WINDS WILL GENERALLY BE CALM THROUGH
SUNRISE THEN INCREASE TO AROUND 10 MPH FROM THE SOUTHWEST...THEN
BECOME LIGHT AFTER SUNSET.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
739 AM EDT TUE AUG 14 2012
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
/ISSUED AT 324 AM EDT TUE AUG 14 2012/
UPPER SHORT WAVE ENERGY EMBEDDED IN A LONG WAVE TROUGH THAT
STRETCHES FROM THE GREAT LAKES TO THE NORTH CENTRAL GULF REGION...
HAS SPARKED CONTINUED CONVECTION ACROSS EASTERN AL AND INTO NW AND
WEST CENTRAL GA EARLY THIS MORNING. GFS...NAM...RUC AND HRRR MODELS
HOLD THIS CONVECTION TOGETHER AND BRING AT LEAST SCATTERED SHOWERS
INTO THE ATLANTA METRO AREA AROUND 8-10 AM THIS MORNING. HOWEVER...
CANNOT RULE OUT AN ISOLATED RUMBLE OF THUNDER DURING THE MORNING
HOURS. EXPECT THIS INITIAL CONVECTIVE ACTIVITY TO PUSH EAST AND
SOUTH BUT WEAKEN THROUGH THE MORNING HOURS. THEN A COLD FRONT...
CURRENTLY ANALYZED ACROSS WESTERN TN... WILL PUSH INTO NW GA LATER
THIS AFTERNOON. THIS FRONT WILL PROVIDE THE SPARK FOR A SECOND ROUND
OF CONVECTION... THAT BEGINS ACROSS NORTH GA... THEN SPREADS SOUTH
ACROSS THE ATLANTA AREA DURING THE LATE AFTERNOON TO EARLY EVENING
HOURS. MODEST INSTABILITIES OF 1500-2500 CAPE AND LACK OF STRONG
UPPER SUPPORT SUGGEST THE ASSOCIATED THUNDERSTORMS SHOULD REMAIN
BELOW SEVERE LIMITS... HOWEVER SMALL HAIL AND WIND GUSTS TO 45 MPH
ARE LIKELY WITH THE STRONGER STORMS. EXPECT THESE STORMS TO MOVE
FAST ENOUGH TO THE SOUTH AND SOUTHEAST TO LESSON ANY LOCALIZED FLOOD
THREAT. THE NAM AND GFS ARE IN GOOD AGREEMENT WITH THE FRONT... AND
ARE SLOW PUSHING THE FRONT SOUTH... NOT CLEARING THE ATLANTA METRO
AREA UNTIL SOMETIME WEDNESDAY MORNING. BOTH MODELS STALL THE FRONT
ACROSS CENTRAL GA ON WEDNESDAY... WARRANTING A SLIGHT CHANCE OF
THUNDER THERE THROUGH WEDNESDAY AFTERNOON. OTHERWISE... TOOK A MAV
AND MET BLEND FOR HIGHS AND LOWS THROUGH THE SHORT TERM... WITH
COOLER LOWS EXPECTED ACROSS NORTH GA LATE TONIGHT BEHIND THE FRONT.
DESPITE THE DRIER/COOLER AIR SPREADING INTO THE AREA ON WEDNESDAY
BEHIND THE FRONT... EXPECT DAYTIME HIGHS TO STILL CLIMB INTO THE
UPPER 80S OR LOWER 90S FOR MOST AREAS AS GUIDANCE INDICATES.
39
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED AT 324 AM EDT TUE AUG 14 2012/
EASTERN U.S. REMAINS UNDER THE INFLUENCE OF THE LONG WAVE UPPER
TROUGH THROUGH THE EXTENDED FORECAST PERIOD. TROUGH STARTS OUT
RATHER FLAT AT MIDWEEK BEHIND AN EXITING SHORT WAVE...BUT SHARPENS UP
AND DEEPENS AS WE APPROACH THE WEEKEND. SHOULD SEE ANOTHER MOSTLY DRY
AND MILD BREAK WEDNESDAY NIGHT AND THURSDAY WITH PRECIPITATION
CHANCES INCREASING ONCE AGAIN AS WE HEAD INTO THE UPCOMING WEEKEND.
DEEP UPPER TROUGH DRIVES ANOTHER FAIRLY STOUT COLD FRONT INTO THE
STATE FOR THE WEEKEND. HARD TO TIME THE BEST PERIODS FOR
PRECIPITATION THROUGH THE WEEKEND AS THE FRONT LINGERS AND SHORT
WAVES ROTATE THROUGH THE LONG WAVE TROUGH SO I HAVE KEPT POPS IN THE
CHANCE RANGE FRIDAY THROUGH SUNDAY. SHOULD START TO SEE A BIT OF
BREAK BY MONDAY AS THE FRONT SINKS SOUTH ALLOWING DRIER AIR TO FILTER
IN AND THE UPPER TROUGH AXIS SHIFTS EAST OF THE STATE.
20
&&
.AVIATION...
12Z UPDATE...
AN UPPER DISTURBANCE IS SPARKING THUNDERSTORMS OVER EAST CENTRAL AL
THIS MORNING. TIMING TOOL INDICATES TSTMS WILL PUSH ACROSS THE
ATLANTA AREA TAF SITES BETWEEN 13-15Z THIS MORNING. MAY SEE BRIEF
MVFR CIGS WITH THE HEAVIER CONVECTION... BUT EXPECT MID LEVEL VFR
CIGS TO PREVAIL. A FRONTAL BOUNDARY WILL PUSH INTO NW GA LATER THIS
AFTERNOON WITH SCATTERED CONVECTION DEVELOPING OUT AHEAD DURING MAX
HEATING. MODELS AGREE THIS TSTM ACTIVITY WILL PUSH ACROSS THE
ATLANTA TAF SITES DURING THE LATE AFTERNOON OR EARLY EVENING HOURS.
OTHERWISE... LIGHT SW WINDS THIS MORNING WILL INCREASE TO AROUND
8-10KTS BY 15-16Z...THEN BECOME MORE WESTERLY THIS EVENING AND
OVERNIGHT AHEAD OF AN APPROACHING COLD FRONT. WET GROUNDS AHEAD OF
THE COLD FRONT WILL RESULT IN IFR CIGS BY 09Z TONIGHT. THE DRIER NW
FLOW BEHIND THE COLD FRONT SHOULD CLEAR LOW CLOUDS OUT BY 13-14Z WED.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM TO HIGH ON ALL ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 70 91 67 / 50 30 20 10
ATLANTA 87 70 89 70 / 50 30 20 10
BLAIRSVILLE 82 65 83 60 / 40 30 20 10
CARTERSVILLE 87 67 88 62 / 40 30 20 10
COLUMBUS 90 72 93 72 / 50 30 20 10
GAINESVILLE 85 69 88 67 / 50 30 20 10
MACON 92 71 92 71 / 50 30 20 10
ROME 87 66 90 62 / 50 30 10 10
PEACHTREE CITY 87 68 89 64 / 50 30 20 5
VIDALIA 92 72 92 73 / 50 30 20 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...39
LONG TERM....20
AVIATION...39
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
509 AM EDT TUE AUG 14 2012
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
/ISSUED AT 324 AM EDT TUE AUG 14 2012/
UPPER SHORT WAVE ENERGY EMBEDDED IN A LONG WAVE TROUGH THAT
STRETCHES FROM THE GREAT LAKES TO THE NORTH CENTRAL GULF REGION...
HAS SPARKED CONTINUED CONVECTION ACROSS EASTERN AL AND INTO NW AND
WEST CENTRAL GA EARLY THIS MORNING. GFS...NAM...RUC AND HRRR MODELS
HOLD THIS CONVECTION TOGETHER AND BRING AT LEAST SCATTERED SHOWERS
INTO THE ATLANTA METRO AREA AROUND 8-10 AM THIS MORNING. HOWEVER...
CANNOT RULE OUT AN ISOLATED RUMBLE OF THUNDER DURING THE MORNING
HOURS. EXPECT THIS INITIAL CONVECTIVE ACTIVITY TO PUSH EAST AND
SOUTH BUT WEAKEN THROUGH THE MORNING HOURS. THEN A COLD FRONT...
CURRENTLY ANALYZED ACROSS WESTERN TN... WILL PUSH INTO NW GA LATER
THIS AFTERNOON. THIS FRONT WILL PROVIDE THE SPARK FOR A SECOND ROUND
OF CONVECTION... THAT BEGINS ACROSS NORTH GA... THEN SPREADS SOUTH
ACROSS THE ATLANTA AREA DURING THE LATE AFTERNOON TO EARLY EVENING
HOURS. MODEST INSTABILITIES OF 1500-2500 CAPE AND LACK OF STRONG
UPPER SUPPORT SUGGEST THE ASSOCIATED THUNDERSTORMS SHOULD REMAIN
BELOW SEVERE LIMITS... HOWEVER SMALL HAIL AND WIND GUSTS TO 45 MPH
ARE LIKELY WITH THE STRONGER STORMS. EXPECT THESE STORMS TO MOVE
FAST ENOUGH TO THE SOUTH AND SOUTHEAST TO LESSON ANY LOCALIZED FLOOD
THREAT. THE NAM AND GFS ARE IN GOOD AGREEMENT WITH THE FRONT... AND
ARE SLOW PUSHING THE FRONT SOUTH... NOT CLEARING THE ATLANTA METRO
AREA UNTIL SOMETIME WEDNESDAY MORNING. BOTH MODELS STALL THE FRONT
ACROSS CENTRAL GA ON WEDNESDAY... WARRANTING A SLIGHT CHANCE OF
THUNDER THERE THROUGH WEDNESDAY AFTERNOON. OTHERWISE... TOOK A MAV
AND MET BLEND FOR HIGHS AND LOWS THROUGH THE SHORT TERM... WITH
COOLER LOWS EXPECTED ACROSS NORTH GA LATE TONIGHT BEHIND THE FRONT.
DESPITE THE DRIER/COOLER AIR SPREADING INTO THE AREA ON WEDNESDAY
BEHIND THE FRONT... EXPECT DAYTIME HIGHS TO STILL CLIMB INTO THE
UPPER 80S OR LOWER 90S FOR MOST AREAS AS GUIDANCE INDICATES.
39
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED AT 324 AM EDT TUE AUG 14 2012/
EASTERN U.S. REMAINS UNDER THE INFLUENCE OF THE LONG WAVE UPPER
TROUGH THROUGH THE EXTENDED FORECAST PERIOD. TROUGH STARTS OUT
RATHER FLAT AT MIDWEEK BEHIND AN EXITING SHORT WAVE...BUT SHARPENS UP
AND DEEPENS AS WE APPROACH THE WEEKEND. SHOULD SEE ANOTHER MOSTLY DRY
AND MILD BREAK WEDNESDAY NIGHT AND THURSDAY WITH PRECIPITATION
CHANCES INCREASING ONCE AGAIN AS WE HEAD INTO THE UPCOMING WEEKEND.
DEEP UPPER TROUGH DRIVES ANOTHER FAIRLY STOUT COLD FRONT INTO THE
STATE FOR THE WEEKEND. HARD TO TIME THE BEST PERIODS FOR
PRECIPITATION THROUGH THE WEEKEND AS THE FRONT LINGERS AND SHORT
WAVES ROTATE THROUGH THE LONG WAVE TROUGH SO I HAVE KEPT POPS IN THE
CHANCE RANGE FRIDAY THROUGH SUNDAY. SHOULD START TO SEE A BIT OF
BREAK BY MONDAY AS THE FRONT SINKS SOUTH ALLOWING DRIER AIR TO FILTER
IN AND THE UPPER TROUGH AXIS SHIFTS EAST OF THE STATE.
20
&&
AVIATION...
09Z UPDATE...
AN UPPER DISTURBANCE HAS SPARKED SCATTERED CONVECTION THAT WILL PUSH
ACROSS THE ATLANTA TAF SITES EARLY THIS MORNING. EXPECT A BRIEF
THREAT OF -TSRA THROUGH 11-12Z...WITH PREVAILING -RA CONTINUING
THROUGH 14-15Z. EXPECT TO SEE BRIEF MVFR CIGS THIS MORNING WITH THE
HEAVIER CONVECTION... BUT MID LEVEL VFR CIGS SHOULD PREVAIL BY
MID-LATE MORNING. A FRONTAL BOUNDARY WILL PUSH INTO FAR NW GA LATER
THIS AFTERNOON WITH SCATTERED CONVECTION EXPECTED TO DEVELOP OUT
AHEAD DURING MAX HEATING. MODELS AGREE THIS WILL BRING ANOTHER
THREAT OF TSTMS TO THE ATLANTA TAF SITES BY LATE AFTERNOON OR EARLY
EVENING. OTHERWISE...LIGHT SW WINDS THIS MORNING WILL INCREASE TO
AROUND 8-10KTS BY 15-16Z...AND BECOME MORE WESTERLY BY THIS EVENING.
//ATL CONFIDENCE...09Z UPDATE...
MEDIUM TO HIGH ON ALL ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 70 91 67 / 50 30 20 10
ATLANTA 87 70 89 70 / 50 30 20 10
BLAIRSVILLE 82 65 83 60 / 40 30 20 10
CARTERSVILLE 87 67 88 62 / 40 30 20 10
COLUMBUS 90 72 93 72 / 50 30 20 10
GAINESVILLE 85 69 88 67 / 50 30 20 10
MACON 92 71 92 71 / 50 30 20 10
ROME 87 66 90 62 / 50 30 10 10
PEACHTREE CITY 87 68 89 64 / 50 30 20 5
VIDALIA 92 72 92 73 / 50 30 20 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...39
LONG TERM....20
AVIATION...39
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
324 AM EDT TUE AUG 14 2012
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
UPPER SHORT WAVE ENERGY EMBEDDED IN A LONG WAVE TROUGH THAT STRETCHES
FROM THE GREAT LAKES TO THE NORTH CENTRAL GULF REGION... HAS SPARKED
CONTINUED CONVECTION ACROSS EASTERN AL AND INTO NW AND WEST CENTRAL
GA EARLY THIS MORNING. GFS...NAM...RUC AND HRRR MODELS HOLD THIS
CONVECTION TOGETHER AND BRING AT LEAST SCATTERED SHOWERS INTO THE
ATLANTA METRO AREA AROUND 8-10 AM THIS MORNING. HOWEVER... CANNOT
RULE OUT AN ISOLATED RUMBLE OF THUNDER DURING THE MORNING HOURS.
EXPECT THIS INITIAL CONVECTIVE ACTIVITY TO PUSH EAST AND SOUTH BUT
WEAKEN THROUGH THE MORNING HOURS. THEN A COLD FRONT... CURRENTLY
ANALYZED ACROSS WESTERN TN... WILL PUSH INTO NW GA LATER THIS
AFTERNOON. THIS FRONT WILL PROVIDE THE SPARK FOR A SECOND ROUND OF
CONVECTION... THAT BEGINS ACROSS NORTH GA... THEN SPREADS SOUTH
ACROSS THE ATLANTA AREA DURING THE LATE AFTERNOON TO EARLY EVENING
HOURS. MODEST INSTABILITIES OF 1500-2500 CAPE AND LACK OF STRONG
UPPER SUPPORT SUGGEST THE ASSOCIATED THUNDERSTORMS SHOULD REMAIN
BELOW SEVERE LIMITS... HOWEVER SMALL HAIL AND WIND GUSTS TO 45 MPH
ARE LIKELY WITH THE STRONGER STORMS. EXPECT THESE STORMS TO MOVE
FAST ENOUGH TO THE SOUTH AND SOUTHEAST TO LESSON ANY LOCALIZED FLOOD
THREAT. THE NAM AND GFS ARE IN GOOD AGREEMENT WITH THE FRONT... AND
ARE SLOW PUSHING THE FRONT SOUTH... NOT CLEARING THE ATLANTA METRO
AREA UNTIL SOMETIME WEDNESDAY MORNING. BOTH MODELS STALL THE FRONT
ACROSS CENTRAL GA ON WEDNESDAY... WARRANTING A SLIGHT CHANCE OF
THUNDER THERE THROUGH WEDNESDAY AFTERNOON. OTHERWISE... TOOK A MAV
AND MET BLEND FOR HIGHS AND LOWS THROUGH THE SHORT TERM... WITH
COOLER LOWS EXPECTED ACROSS NORTH GA LATE TONIGHT BEHIND THE FRONT.
DESPITE THE DRIER/COOLER AIR SPREADING INTO THE AREA ON WEDNESDAY
BEHIND THE FRONT... EXPECT DAYTIME HIGHS TO STILL CLIMB INTO THE
UPPER 80S OR LOWER 90S FOR MOST AREAS AS GUIDANCE INDICATES.
39
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
EASTERN U.S. REMAINS UNDER THE INFLUENCE OF THE LONG WAVE UPPER
TROUGH THROUGH THE EXTENDED FORECAST PERIOD. TROUGH STARTS OUT
RATHER FLAT AT MIDWEEK BEHIND AN EXITING SHORT WAVE...BUT SHARPENS UP
AND DEEPENS AS WE APPROACH THE WEEKEND. SHOULD SEE ANOTHER MOSTLY DRY
AND MILD BREAK WEDNESDAY NIGHT AND THURSDAY WITH PRECIPITATION
CHANCES INCREASING ONCE AGAIN AS WE HEAD INTO THE UPCOMING WEEKEND.
DEEP UPPER TROUGH DRIVES ANOTHER FAIRLY STOUT COLD FRONT INTO THE
STATE FOR THE WEEKEND. HARD TO TIME THE BEST PERIODS FOR
PRECIPITATION THROUGH THE WEEKEND AS THE FRONT LINGERS AND SHORT
WAVES ROTATE THROUGH THE LONG WAVE TROUGH SO I HAVE KEPT POPS IN THE
CHANCE RANGE FRIDAY THROUGH SUNDAY. SHOULD START TO SEE A BIT OF
BREAK BY MONDAY AS THE FRONT SINKS SOUTH ALLOWING DRIER AIR TO FILTER
IN AND THE UPPER TROUGH AXIS SHIFTS EAST OF THE STATE.
20
&&
AVIATION...
06Z UPDATE...
INITIAL CONCERN IS SCATTERED CONVECTION OVER AL EARLY THIS MORNING.
TIMING TOOL SUGGEST AT LEAST -SHRA COULD MOVE INTO THE ATLANTA AREA
BY 10-12Z THIS MORNING. THE UPPER SHORT WAVE IS WEAKENING...BUT IS
EMBEDDED IN A LONG WAVE TROUGH THAT COULD SUPPORT ON-GOING
CONVECTION AS IT MOVES EASTWARD. HAVE ELECTED TO SHOW MID LEVEL CIGS
ASSOCIATED WITH THIS ACTIVITY FOR NOW AS SOME MODELS INDICATE IT MAY
SPLIT NORTH AND SOUTH OF ATLANTA AREA. WILL WATCH THIS ACTIVITY FOR
THE NEXT FEW HOURS... THEN AMEND AS NECESSARY IF CONVECTION HOLDS
TOGETHER AND ENTERS GA LATER THIS MORNING. OTHERWISE... COULD SEE
SOME BRIEF MVFR CIGS DEVELOP THIS MORNING BUT THINK THE MID LEVEL
CIGS SPREADING IN FROM THE WEST WILL DOMINATE THIS MORNING. A
FRONTAL BOUNDARY WILL PUSH INTO FAR NW GA LATER THIS AFTERNOON WITH
SCATTERED CONVECTION EXPECTED OUT AHEAD DURING MAX HEATING. WILL
FOCUS ON THIS CONVECTION FOR NOW. LIGHT WINDS WILL BECOME SW 8-10KTS
BY 15-16Z TODAY.
//ATL CONFIDENCE...06Z UPDATE...
LOW TO MEDIUM ON CONVECTION OR MVFR CIGS THIS MORNING. MEDIUM TO
HIGH ON REMAINING ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 70 91 67 / 50 30 20 10
ATLANTA 87 70 89 70 / 50 30 20 10
BLAIRSVILLE 82 65 83 60 / 40 30 20 10
CARTERSVILLE 87 67 88 62 / 40 30 20 10
COLUMBUS 90 72 93 72 / 50 30 20 10
GAINESVILLE 85 69 88 67 / 50 30 20 10
MACON 92 71 92 71 / 50 30 20 10
ROME 87 66 90 62 / 50 30 10 10
PEACHTREE CITY 87 68 89 64 / 50 30 20 5
VIDALIA 92 72 92 73 / 50 30 20 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...39
LONG TERM....20
AVIATION...39
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
156 AM EDT TUE AUG 14 2012
.UPDATE...
/ISSUED AT 940 PM EDT MON AUG 13 2012/
HAVE TWEAKED POPS AGAIN...KEEPING CHANCE OR SLIGHT CHANCE
OVER MUCH OF THE CWA EXCEPT EAST CENTRAL. WATCHING THUNDERSTORMS IN
MISSISSIPPI AND MAY HAVE TO ADJUST POPS AGAIN LATER. WITH RAIN
COOLED AIR ACROSS THE NORTHWEST...HOURLY TEMPERATURES HAVE FALLEN
MORE RAPIDLY AND HAVE TRIED TO ADJUST FOR THAT IN THE GRIDS.
41
.PREVIOUS UPDATE...
/ISSUED AT 800 PM EDT MON AUG 13 2012/
DIFFICULT FORECAST FOR TONIGHT...WITH NONE OF THE MODELS REALLY
HAVING A GOOD HANDLE ON THE CURRENT SHOWER AND THUNDERSTORM ACTIVITY.
HAVE SIGNIFICANTLY UPDATED POPS AND WEATHER GRIDS TO ACCOUNT FOR
CURRENT CONVECTION ASSOCIATED WITH MCS THAT MOVED EASTWARD OUT OF
TN/AL THIS AFTERNOON. LATEST LAPS SHOWING BEST INSTABILITY ALONG THE
GA/AL LINE...WITH AREAS FURTHER EAST FAR MORE STABLE. IN
GENERAL...EXPECT AN OVERALL WEAKENING TREND AS THIS LARGE AREA OF
PRECIPITATION CONTINUES TO MOVE EASTWARD.
WILL BE MAKING PERIODIC UPDATES TO THE FORECAST AS NECESSARY AS
THIS EVENT CONTINUES TO UNFOLD. HAVE GONE AHEAD AND CANCELLED THE
SVR WATCH FOR THE FAR NORTHEAST PORTION OF THE STATE.
31
&&
.PREV DISCUSSION... /ISSUED 308 PM EDT MON AUG 13 2012/
..SEVERE STORMS EXPECTED THROUGH THIS EVENING EXTREME NW GEORGIA...
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ALL EYES ON MCS OVER TENNESSEE AND ALABAMA WHICH CONTINUES TO MAKE
STEADY PROGRESS TO THE EAST. NOW HAVE A WATCH UP FOR THE EXTREME
NW CORNER OF THE FORECAST AREA WHERE THERE IS IRONICALLY LITTLE TO
NO INSTABILITY AT THIS TIME. SYSTEM HAS HOWEVER BEEN ABLE TO BRING
ALONG ITS OWN ENHANCED MOISTURE AND INSTABILITY ALTHOUGH ITS
ABILITY TO DO SO AS IT APPROACHES THE FORECAST AREA REMAINS IN
QUESTION. RAP SHORT TERM GUIDANCE DOES SHOW INCREASED INSTABILITY
WITHIN THE NEXT 2 HOURS PUSHING INTO THE NW ZONES BUT ONLY ON THE
ORDER OF 1500 TO 2000 J/KG...MUCH LESS THAN UPSTREAM VALUES WE HAVE
SEEN. SO IN SHORT...EXPECTING SVR POTENTIAL TO INCREASE FOR THE
EXTREME NW AND WESTERN TIER OVER THE NEXT SEVERAL HOURS BUT TRENDS
IN INSTABILITY SUGGEST A LIMITED TIMEFRAME FOR CONVECTIVE
POTENTIAL. ALSO WATCHING DEVELOPING AREA OF DCAPE IN EXCESS OF
1000 J/KG WHICH COULD ALLOW FOR ISOLATED SVR OUTSIDE OF CURRENT
WATCH AREA FROM COLUMBUS UP TO LA GRANGE.
QUESTIONS ALSO SURROUND HOW FAR ACTUAL LINE OF SHOWERS AND STORMS
MAKES IT TO THE EAST. AS MENTIONED...EXPECTING A SHARP INSTABILITY
GRADIENT AND MOMENTUM LOOKS TO ONLY TAKE THIS SYSTEM SO FAR. HRRR
IS DIMINISHING LINE AND THEN GENERATES NEW CONVECTION ALONG ACTUAL
FRONT INTO THE OVERNIGHT HOURS. GIVEN CURRENT TRENDS...WILL EXPAND
POP COVERAGE SLIGHTLY EASTWARD BUT ONLY CARRY LOW END CHANCE POPS
INTO THE OVERNIGHT PERIOD FOR THE ATLANTA METRO AND POINTS NORTH
AND WEST.
BY 12Z...FRONT WILL SAG INTO NORTH GEORGIA WITH DRIER AIR
BEGINNING TO FILTER IN. WILL BE IN LARGE SCALE TROUGH PATTERN BUT
NO NOTABLE SHORTWAVES EMBEDDED IN FLOW UNTIL 00Z. THIS COULD
ENHANCE POPS FIELD BUT PRIMARILY OVER THE SOUTHERN TIER WHERE I
HAVE INCLUDED LIKELY POPS.
DEESE
LONG TERM /WEDNESDAY THROUGH MONDAY/...
NO SIGNIFICANT CHANGES PLANNED.
BDL
MEDIUM RANGE MODELS REMAIN CONSISTENT THROUGH THE EXTENDED
FORECAST PERIOD KEEPING THE EASTERN U.S. UNDER PERSISTENT LONG
WAVE TROUGHING. ALTHOUGH THE LARGE SCALE PATTERN REMAINS FAIRLY
STATIC...THE SMALLER SCALE REMAINS QUITE ACTIVE AS SHORT WAVES
SWING THROUGH THE TROUGH DIGGING OUT OF THE NORTHERN PLAINS INTO
THE OHIO VALLEY. THIS PATTERN KEEPS THE BEST UPPER DYNAMICS NORTH
OF THE REGION...BUT MANAGES TO DRIVE A SERIES OF ASSOCIATED
SURFACE FRONTS THROUGH THE STATE. FIRST SYSTEM IS EXITING AS WE
HEAD INTO THE EXTENDED PERIOD SO ANOTHER SHOT OF MILDER AND FAIRLY
DRY AIR SETTLES IN FOR THE MIDDLE OF THE WEEK. NEXT SYSTEM IS
EXPECTED FOR THE END OF THE WEEK INTO THE WEEKEND. THIS
CORRESPONDS WELL WITH PREVIOUS MODEL RUNS SO THERE ARE NO
SIGNIFICANT CHANGES TO THE PREVIOUS EXTENDED FORECAST THEMES.
20
&&
.AVIATION...
06Z UPDATE...
INITIAL CONCERN IS SCATTERED CONVECTION OVER AL EARLY THIS MORNING.
TIMING TOOL SUGGEST AT LEAST -SHRA COULD MOVE INTO THE ATLANTA AREA
BY 10-12Z THIS MORNING. THE UPPER SHORT WAVE IS WEAKENING...BUT IS
EMBEDDED IN A LONG WAVE TROUGH THAT COULD SUPPORT ON-GOING
CONVECTION AS IT MOVES EASTWARD. HAVE ELECTED TO SHOW MID LEVEL CIGS
ASSOCIATED WITH THIS ACTIVITY FOR NOW AS SOME MODELS INDICATE IT MAY
SPLIT NORTH AND SOUTH OF ATLANTA AREA. WILL WATCH THIS ACTIVITY FOR
THE NEXT FEW HOURS... THEN AMEND AS NECESSARY IF CONVECTION HOLDS
TOGETHER AND ENTERS GA LATER THIS MORNING. OTHERWISE... COULD SEE
SOME BRIEF MVFR CIGS DEVELOP THIS MORNING BUT THINK THE MID LEVEL
CIGS SPREADING IN FROM THE WEST WILL DOMINATE THIS MORNING. A
FRONTAL BOUNDARY WILL PUSH INTO FAR NW GA LATER THIS AFTERNOON WITH
SCATTERED CONVECTION EXPECTED OUT AHEAD DURING MAX HEATING. WILL
FOCUS ON THIS CONVECTION FOR NOW. LIGHT WINDS WILL BECOME SW 8-10KTS
BY 15-16Z TODAY.
//ATL CONFIDENCE...06Z UPDATE...
LOW TO MEDIUM ON CONVECTION OR MVFR CIGS THIS MORNING. MEDIUM TO
HIGH ON REMAINING ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 65 90 69 91 / 20 40 20 10
ATLANTA 70 87 71 88 / 60 30 20 10
BLAIRSVILLE 63 83 64 85 / 50 30 20 5
CARTERSVILLE 67 87 68 89 / 70 30 20 5
COLUMBUS 71 90 74 91 / 60 40 20 20
GAINESVILLE 67 87 69 88 / 50 30 20 10
MACON 67 91 72 91 / 20 50 30 20
ROME 67 87 68 89 / 50 30 20 5
PEACHTREE CITY 67 87 69 89 / 60 30 20 10
VIDALIA 70 92 75 92 / 10 60 50 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...41/39
LONG TERM....31
AVIATION...39
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1139 PM CDT MON AUG 13 2012
.DISCUSSION...
ISSUED 850 PM CDT MON AUG 13 2012
CLEARING LINE HAS PUSHED TO ABOUT A MACOMB-PEORIA-LACON LINE AT
MID EVENING. MAIN QUESTION IS HOW MUCH FURTHER SOUTH THIS WILL
MAKE IT. HAVE BEEN SEEING SOME EVIDENCE THAT AREAS EAST OF I-39
ARE NOT CLEARING OUT QUITE AS FAST AS FURTHER SOUTHWEST...AND
AN AREA OF STRATUS BELOW 1000 FEET HAS BEEN DEVELOPING FROM
DECATUR TO PONTIAC. AWIPS TIME-OF-ARRIVAL TOOL AND RAP MODEL CLOUD
GUIDANCE HAS THE WESTERN CWA MOSTLY CLEAR BEFORE MIDNIGHT...BUT
THE RAP INDICATES THE CLOUDS ACROSS THE EAST WILL BE TOUGH TO
ERODE WITH A BOUNDARY STILL IN THE AREA. HAVE ADDED SOME MENTION
OF PATCHY FOG OVERNIGHT...ESPECIALLY IN AREAS THAT WILL SEE SOME
SUBSTANTIAL CLEARING AND LIGHTER WINDS.
UPDATED ZONES/GRIDS HAVE BEEN SENT.
GEELHART
&&
.AVIATION...
ISSUED 1137 PM CDT MON AUG 13 2012
CLEARING LINE ROUGHLY EXTENDS FROM KIJX-KPNT AT 04Z. EASTERN
FLANKS OF THE CLEARING HAVE NOT MADE ANY REAL PROGRESS AS OF
LATE...AND PLAN TO KEEP IFR/LIFR CONDITIONS AT KCMI/KDEC THROUGH
THE NIGHT. 500 FOOT STRATUS DECK BECOMING WIDESPREAD ACROSS EAST
CENTRAL ILLINOIS...WITH LATEST MODEL GUIDANCE SHOWING IT HANGING
ON THROUGH ABOUT 13Z. THINK THE CLOUDS AT KDEC/KCMI WILL KEEP THE
VISIBILITY FROM GETTING OUT OF HAND...BUT AREAS FURTHER NORTH THAT
HAVE CLEAR SKIES IMMINENT OR ONGOING WILL BE SUSCEPTIBLE TO SOME
AREAS OF FOG. HAVE ALREADY SEEN VISIBILITIES DOWN TO 1/4 MILE AT
TIMES AT KGBG AND KC75...AND FEEL THAT KBMI/KPIA WILL BE
VULNERABLE AS WELL. ONCE THE LOW CLOUDS AND FOG LIFT AROUND
13-15Z...VFR CONDITIONS WILL PREVAIL AT ALL SITES.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 300 PM CDT MON AUG 13 2012
CLOUDY...COOL...AND SHOWERY WEATHER WILL CONTINUE THIS EVENING
BEFORE THE SURFACE LOW FINALLY DEPARTS INTO INDIANA. FOR TUESDAY
AND WEDNESDAY...SURFACE HIGH PRESSURE WILL KEEP THE WEATHER
QUIET...WITH MUCH WARMER TEMPS ON WEDNESDAY. THEN A COLD FRONT
WILL BRING SHOWERS AND STORMS BACK TO THE AREA THURSDAY AND
THURSDAY NIGHT...FOLLOWED BY A RETURN TO BELOW NORMAL TEMPS FOR
NEXT WEEKEND AND INTO NEXT WEEK.
SHORT TERM...TONIGHT THROUGH THURSDAY.
INSTABILITY NEAR THE SURFACE LOW WILL ALLOW SHOWERS AND POSSIBLY A
FEW THUNDERSTORMS TO LINGER INTO THE EVENING...MAINLY EAST OF
I-55. THE LOW CENTER IS EXPECTED TO TRACK JUST SOUTH OF
SPRINGFIELD TO LAWRENCEVILLE. THE SPC DY1 OUTLOOK STILL INCLUDES
OUR FAR SOUTHEAST COUNTIES NEAR LWV...WHERE MU CAPES ARE NEAR 1000
J/KG AND EFFECTIVE SHEAR IS 25-30KT. BY MIDNIGHT...THE LOW SHOULD
BE INTO INDIANA...AND INTO KY BY 12Z TUES. WE KEPT SOME SLIGHT
CHANCE POPS AFTER MIDNIGHT EAST OF I-57.
TUESDAY WILL SEE HIGH PRESSURE ARRIVING...BUT THE TYPICALLY COOLER
AIR BEHIND THE LOW WILL BE SHORT LIVED AS 850MB TEMPS WARM FROM 12
TO 16C TUES AFTERNOON. THAT WARMING ALONG WITH INCREASING SUNSHINE
AS THE DAY PROGRESSES WILL HELP TEMPS WARM INTO THE LOW TO MID
80S. THAT WARMING TREND WILL INTENSIFY ON WEDNESDAY AS THE THERMAL
RIDGE PEAKS AHEAD OF THE APPROACHING COLD FRONT. HIGHS ON WED ARE
EXPECTED TO CLIMB ABOVE NORMAL IN THE UPPER 80S TO LOWER 90S.
A FEW SHOWERS MAY DEVELOP THURSDAY MORNING...BUT THE BULK OF THE
PRECIPITATION ACCUMULATION SHOULD COME THURS AFTERNOON AND
EVENING. THE NAM IS THE FAST OUTLIER WITH TIMING OF THE FRONT INTO
THE MID CWA BY 18Z...BUT WE DECIDED TO CONTINUE WITH THE CONSENSUS
SLOWER SOLUTION OF THE GFS/CANADIAN GEM/ECMWF. WE HAVE LIKELY POPS
IN THE NW HALF THURS AND THE SE HALF THURS NIGHT.
LONG TERM...FRIDAY THROUGH MONDAY.
A COOLER AIRMASS WILL SETTLE INTO THE UPPER MIDWEST FOR FRIDAY AND
LINGER THROUGH MONDAY...WITH BELOW NORMAL TEMPS ACROSS THE BOARD.
AS THE UPPER TROUGH AXIS MOVES ACROSS CENTRAL IL ON FRIDAY...WE
CANT RULE OUT A FEW SPRINKLES DEVELOPING IN THE STEEPER LAPSE
RATES. HOWEVER...WE KEPT THE FORECAST DRY FOR NOW. THE REMAINDER
OF THE WEEKEND AND INTO MONDAY IS FORECAST TO BE DRY BY THE ECMWF.
THE OVERLY MOIST GFS IS GENERATING DIURNAL SHOWERS EACH DAY OF THE
EXTENDED. NORTHWEST FLOW ALOFT MAY ALLOW FOR A STRAY SHORTWAVE AT
SOME POINT THIS WEEKEND...BUT CHANCES ARE LOW ENOUGH TO LEAVE OUT
TRYING TO PINPOINT TIMING THIS EARLY.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1151 AM CDT TUE AUG 14 2012
.UPDATE...
UPDATED TO TWEAK TEMPS AND PRECIP FOR THE REMAINDER OF THE DAY.
LARGE AREA OF PRECIP CONTINUES TO AFFECT ALL OF SOUTH CENTRAL AND
WILL EVENTUALLY ENCOMPASS ALL OF SE KS. THIS AREA HAS PRETTY MUCH
PUSHED OUT OF CENTRAL KS. THE PRECIP IS THE RESULT OF AN UPPER WAVE
THAT MOVED OUT OF THE ROCKIES. THE RUC CURRENTLY SHOWS A NICE COLD
POCKET IN THE 305-310K LAYER OVER EASTERN KS WITH FAIRLY STRONG
UPGLIDE INTO THE COLD POCKET OVER THE SOUTHERN HALF OF THE FORECAST
AREA.
THE CLOUDS ASSOCIATED WITH THE PRECIP WILL HOLD DOWN TEMPS
TODAY...ESPECIALLY ACROSS SOUTH CENTRAL AND SE KS. SO WENT AHEAD
AND DECREASED MAXES TODAY OVER THESE AREAS.
&&
.AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MAIN AVIATION CONCERN WILL BE LOWER CIGS ASSOCIATED WITH PRECIP
TODAY INTO THE EVENING HOURS.
A FAIRLY LARGE AREA OF PRECIP IS EXPECTED TO CONTINUE AFFECTING
SOUTH CENTRAL AND SE KS TODAY INTO THE EARLY EVENING HOURS. THIS
AREA OF PRECIP IS ASSOCIATED WITH AN UPPER WAVE THAT MOVED OUT OF
THE ROCKIES THIS MORNING WHICH IS NOW PROVIDING SOME ISENTROPIC
UPGLIDE OVER SOUTHERN KS THIS AFTERNOON. WHILE THE MAJORITY OF THE
CIGS ARE IN THE VFR LEVELS...THERE WILL BE A FEW MVFR CIGS IN AREAS
OF PRECIP. THERE WAS EVEN A BRIEF PERIOD OF IFR CIGS JUST NORTH OF
THE PRECIP OVER CENTRAL KS. HOWEVER THE IFR CIGS ARE EXPECTED TO BE
VERY BRIEF. BY THE EARLY EVENING HOURS ONLY SE KS SHOULD STILL SEE
SOME SCT SHOWERS WITH THIS ACTIVITY SOUTH OF THE FORECAST AREA BY
03Z.
LAWSON
&&
.PREV DISCUSSION... /ISSUED 624 AM CDT TUE AUG 14 2012/
AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
NUMEROUS RAIN SHOWERS FROM ASSOCIATED UPPER LEVEL WAVE WILL SPREAD
EASTWARD ACROSS THE REGION...HOWEVER CLOUD HEIGHTS WILL REMAIN
GENERALLY ABOVE 5000FT SO VFR CONDITIONS ARE EXPECTED TO PREVAIL
FOR ALL SITES. MID-LEVEL CLOUDS WILL BEGIN TO CLEAR OUT FROM WEST
TO EAST THIS AFTERNOON WITH EASTERLY WINDS SWITCHING TO A MORE
SOUTHERLY DIRECTION THIS EVENING.
JAKUB
PREV DISCUSSION... /ISSUED 251 AM CDT TUE AUG 14 2012/
MAIN FORECAST CONCERNS: PRECIPITATION CHANCES OVER THE NEXT FEW
DAYS AND OTHERWISE TEMPERATURES.
TODAY-TONIGHT:
SHORTWAVE TROUGH WITH AN ACCOMPANYING UPPER JET STREAK WILL CONTINUE
MOVING SOUTHEASTWARD ACROSS THE CENTRAL PLAINS TODAY. FORCING WITH
THE WAVE LOOKS DECENT WITH MOISTURE/INSTABILITY LIMITED. THEREFORE
NOT PLANNING TO INCREASE RAIN CHANCES ABOVE 40-60%. RAIN AMOUNTS
SHOULD BE LIGHT (FEW HUNDREDTHS UP TO 0.25 INCH). CLOUD
COVER/PRECIPITATION COULD LIMIT INSOLATION FOR MUCH OF THE DAY AND
SHOULD RESULT IN COOLER THAN SEASONAL HIGH TEMPERATURES AROUND 80 TO
THE MID 80S. PRECIPITATION SHOULD PUSH SOUTHWARD OUT OF THE AREA
LATER THIS AFTERNOON WITH CLEARING SKIES FOR TONIGHT.
WEDNESDAY-THURSDAY:
A STRONG UPPER TROUGH AXIS WILL SWEEP ACROSS THE NORTHERN
PLAINS/UPPER MISSISSIPPI VALLEY WHICH WILL SEND A STRONG COLD FRONT
SOUTHWARD THROUGH THE CENTRAL PLAINS. AHEAD OF THE APPROACHING
FRONT...WEDNESDAY WILL BE A HOT DAY WITH GUSTY SOUTH-SOUTHWESTERLY
WINDS AND PROGGED 850 TEMPERATURES OF 23-28 CELSIUS (NAM-WRF/ECMWF).
GOING HIGHS OF MID 90S TO AROUND 100 LOOK REASONABLE. THE COLD FRONT
WILL MOVE SOUTHWARD ACROSS OUR AREA LATE WEDNESDAY NIGHT THROUGH
THURSDAY. THERE WILL BE A CHANCE OF THUNDERSTORMS AS THE FRONT MOVES
THROUGH. HOWEVER...MAIN UPPER LEVEL SUPPORT SHOULD REMAIN WELL
NORTHEAST OF THE AREA AND MID-LEVEL TEMPERATURES ARE VERY WARM
WEDNESDAY NIGHT BEFORE COOLING SLIGHTLY ON THURSDAY. HIGHEST
THUNDERSTORM CHANCES LOOK TO BE IN THE SOUTHEAST THURSDAY PM/EVE
AS THE FRONTAL TIMING COINCIDES WITH PEAK HEATING/INSTABILITY.
LESSER CHANCES ARE SLATED ELSEWHERE. MUCH COOLER AIR WILL BEGIN
SPREADING SOUTHWARD THURSDAY INTO THURSDAY NIGHT.
FRIDAY-MONDAY:
UPPER PATTERN WILL AMPLIFY FRIDAY INTO THE WEEKEND WITH A LONGWAVE
UPPER TROUGH FROM SOUTHEASTERN CANADA DOWN THROUGH THE EASTERN
CONUS...AND UPPER RIDGING OVER THE WESTERN CONUS. THE ECMWF IS
SLIGHTLY MORE AMPLIFIED THAN THE GFS AND RETAINS THIS INTO
MONDAY...WHEREAS THE GFS BEGINS TO DEAMPLIFY COME EARLY NEXT WEEK.
NORTHWESTERLY FLOW ALOFT WILL PREVAIL OVER OUR FORECAST AREA. COOLER
THAN NORMAL TEMPERATURES FRIDAY AND SATURDAY WILL MODIFY TO CLOSER
TO NORMAL BY MONDAY. A WEAK SHORTWAVE IN THE NORTHWEST FLOW ALOFT
COULD RESULT IN SLIGHT CHANCES FOR SHOWERS/THUNDER SATURDAY.
HOWEVER MOST OF THE PERIOD IS EXPECTED TO REMAIN DRY.
JMC
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 79 65 97 71 / 60 20 10 30
HUTCHINSON 79 64 98 69 / 70 10 10 30
NEWTON 77 64 97 69 / 70 10 10 30
ELDORADO 77 61 96 70 / 60 20 10 20
WINFIELD-KWLD 80 65 96 73 / 80 20 10 20
RUSSELL 82 64 98 64 / 60 10 10 30
GREAT BEND 80 63 98 66 / 50 10 10 30
SALINA 82 64 99 69 / 80 10 10 30
MCPHERSON 78 64 98 69 / 80 10 10 30
COFFEYVILLE 77 62 94 73 / 70 30 10 20
CHANUTE 77 60 94 71 / 70 30 10 20
IOLA 77 60 95 70 / 70 20 10 20
PARSONS-KPPF 76 61 94 73 / 70 30 10 20
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1145 PM MDT MON AUG 13 2012
.UPDATE...
ISSUED AT 1008 PM MDT MON AUG 13 2012
JUST COMPLETED ANOTHER UPDATE. CURRENT PRECIPITATION FORECAST IS
ON TRACK. DID NOT WANT TO MESS WITH EITHER HAVING A PREVAILING
THUNDERSTORM OR EMBEDDED THUNDERSTORM FORECAST CONSIDERING WHAT
IS GOING ON UPSTREAM PLUS THE STRENGTH OF THE LIFT COMING IN.
PRECIPITATION LOOKS TO BE DONE BY 12Z. HRRR/RUC/NAM HINTING AT
SOME PATCHY FOG IN THE WEST...ROUGHLY IN THE AREA THAT RECEIVED
THE RAINFALL THIS EVENING...FROM LATER TONIGHT INTO TOMORROW
MORNING. WILL DEPEND ON HOW MUCH CLEARING WE GET BUT THAT DOES
LOOK REASONABLE CONSIDERING THE TEMPERATURE/DEWPOINT SPREADS ARE
ALREADY NOT THAT FAR APART EVEN WITH THE CLOUD COVER. WILL INSERT
IT INTO THE GRIDS FROM 09Z TO 15Z.
HRRR IS DOING WELL ON THE DEWPOINTS AND CURRENT TEMPERATURES AND
WINDS. SO WILL USE TO ADJUST DEWPOINTS...WINDS AND MINS. ADJUSTED
MINS DOWN IN THE NORTHWEST HALF AND UP A LITTLE IN THE SOUTHEAST
PORTION WHERE MORE CLOUD COVER WILL BE.
UPDATE ISSUED AT 616 PM MDT MON AUG 13 2012
JUST COMPLETED AN UPDATE. SIGNIFICANTLY RAISED POPS IN THE
SOUTHWEST HALF OF THE AREA. SHORTWAVE TROUGH AND RIGHT REAR
QUADRANT OF JET ARE INCREASING THE COVERAGE OF STORMS FURTHER EAST
THAN WHAT WAS PREVIOUSLY DEPICTED. THE HRRR IS CATCHING THE HOURLY
TRENDS ON THE PRECIPITATION VERY WELL AND IS MIRRORED CLOSELY BY
THE 6 HOUR AMOUNTS SHOWN BY THE SREF AND ECMWF. THIS AREA MAKES
VERY GOOD SENSE CONSIDERING THE TRENDS AND THE LIFTING MECHANISMS.
SO FOLLOWED CLOSELY THOSE MODEL DEPICTIONS THROUGH THIS EVENING.
OTHERWISE...INCREASED CLOUD COVER SIGNIFICANTLY THROUGH THE
EVENING. WILL MONITOR TRENDS ON EVERYTHING ELSE THROUGH THE
EVENING. MESOSCALE AFFECTS WILL NO DOUBT WREAK HAVOC ON REMAINING
PARAMETERS THROUGH THE NIGHT.
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 140 PM MDT MON AUG 13 2012
UPPER FLOW WILL BE NORTHWEST TONIGHT/TUESDAY. A SHORTWAVE WILL COME
THROUGH THE FLOW TONIGHT. SUBSIDENCE WILL FOLLOW BEHIND THE WAVE ON
TUESDAY. SURFACE HIGH PRESSURE WILL BE OVER THE AREA TONIGHT. LOW
PRESSURE WILL BE OVER EASTERN WYOMING/NORTHEAST COLORADO TUESDAY.
DYNAMICS FROM THE INCOMING SHORTWAVE TONIGHT ARE SHOWN TO SLIDE
SOUTHEAST FROM EASTERN COLORADO INTO THE SOUTHERN FA. THIS IS WHERE
THE BEST MOISTURE IS AS WELL. PLAN TO GO WITH CHANCE POPS FOR THIS
AREA AND SLIGHT CHANCE POPS WHERE THERE IS LESS MOISTURE AND
FORCING. SUBSIDENCE WILL KEEP POPS NIL TUESDAY.
MIN TEMPERATURES TONIGHT WILL BE WARMER THAN LAST NIGHT AS COOLER
TEMPERATURES HAVE MOVED PAST THE FA AND SOUTH WINDS WILL MAINTAIN
GOOD MIXING OVERNIGHT. EXPECT READINGS IN THE UPPER 50S/LOWER 60S.
MAX TEMPERATURES TUESDAY WILL RISE INTO THE LOWER 90S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 250 PM MDT MON AUG 13 2012
THE FIRST SIGNIFICANT WEATHER FEATURE TO IMPACT THE AREA DURING
THIS PERIOD WILL BE A STRONG UPPER SHORT WAVE TROUGH NOW OVER
BRITISH COLUMBIA AS SEEN IN WATER VAPOR IMAGERY. THIS TROUGH WILL
MOVE SOUTHEAST AND SWEEP ACROSS THE C-N PLAINS WED-WED NIGHT. AT
THE SURFACE A STRONG COLD FRONT WILL MOVE RAPIDLY SOUTH ACROSS THE
FORECAST AREA WEDNESDAY EVENING AND WILL CLEAR THE AREA LATE
WEDNESDAY NIGHT. THESE FEATURES WILL GIVE AN OPPORTUNITY FOR
SHOWERS AND THUNDERSTORMS MAINLY WEDNESDAY NIGHT. MUCH COLDER AIR
WILL SETTLE INTO THE REGION FOR THURSDAY AND FRIDAY WITH HIGHS IN
THE UPPER 70S TO LOWER 80S.
BOTH THE EC AND GFS SUGGEST A MODERATELY STRONG NORTHWEST FLOW
ALOFT FOR THE REMAINDER OF THE WEEK AND THROUGH THE WEEKEND. THE
EC IS MOSTLY DRY WITH THIS PATTERN BUT THE GFS SUGGESTS THE
POTENTIAL FOR SEVERAL EPISODES OF PRECIPITATION. BOTH MODELS HINT
AT SEVERAL WEAK...FAST-MOVING SHORT WAVE TROUGHS SLIDING SOUTHEAST
THROUGH THE FLOW BUT TIMING WILL BE DIFFICULT. LOW POPS ARE
INCLUDED IN THE EXTENDED FORECAST AS A RESULT. ANY CONVECTION
WHICH INITIATES ON THE CHEYENNE RIDGE WOULD MOVE INTO THE
AREA...AIDED BY SOUTHEAST SURFACE FLOW WHICH WILL ENHANCE STORM
INFLOW TO KEEP CONVECTION GOING FOR A FEW HOURS BEFORE
DISSIPATION.
TEMPERATURES OVER THE WEEKEND WILL RETURN TO CLOSER TO NORMAL
VALUES BUT THE EXTREME HEAT HAS ABATED FOR AT LEAST THE NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1142 PM MDT MON AUG 13 2012
LINGERING LIGHT RAIN SHOWERS WILL BE AT OR NEAR BOTH SITES FOR THE
NEXT HOUR OR TWO. ONCE THE SHOWERS END AND SOME CLEARING OCCURS...MODELS
HAVE COME MORE INTO AGREEMENT OF BRINGING MVFR CEILINGS AND VISIBILITIES
INTO BOTH SITES WITH THE WORST CONDITIONS AT KGLD. CLEARING DOES
NOT OCCUR UNTIL MID TO LATE MORNING. ONCE THE CLEARING OCCURS...GUSTY
SOUTHERLY WINDS WILL BEGIN AND CONTINUE THROUGH MOST OF THE REST
OF THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...FS
LONG TERM...DLF
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1018 PM MDT MON AUG 13 2012
.UPDATE...
ISSUED AT 1008 PM MDT MON AUG 13 2012
JUST COMPLETED ANOTHER UPDATE. CURRENT PRECIPITATION FORECAST IS
ON TRACK. DID NOT WANT TO MESS WITH EITHER HAVING A PREVAILING
THUNDERSTORM OR EMBEDDED THUNDERSTORM FORECAST CONSIDERING WHAT
IS GOING ON UPSTREAM PLUS THE STRENGTH OF THE LIFT COMING IN.
PRECIPITATION LOOKS TO BE DONE BY 12Z. HRRR/RUC/NAM HINTING AT
SOME PATCHY FOG IN THE WEST...ROUGHLY IN THE AREA THAT RECEIVED
THE RAINFALL THIS EVENING...FROM LATER TONIGHT INTO TOMORROW
MORNING. WILL DEPEND ON HOW MUCH CLEARING WE GET BUT THAT DOES
LOOK REASONABLE CONSIDERING THE TEMPERATURE/DEWPOINT SPREADS ARE
ALREADY NOT THAT FAR APART EVEN WITH THE CLOUD COVER. WILL INSERT
IT INTO THE GRIDS FROM 09Z TO 15Z.
HRRR IS DOING WELL ON THE DEWPOINTS AND CURRENT TEMPERATURES AND
WINDS. SO WILL USE TO ADJUST DEWPOINTS...WINDS AND MINS. ADJUSTED
MINS DOWN IN THE NORTHWEST HALF AND UP A LITTLE IN THE SOUTHEAST
PORTION WHERE MORE CLOUD COVER WILL BE.
UPDATE ISSUED AT 616 PM MDT MON AUG 13 2012
JUST COMPLETED AN UPDATE. SIGNIFICANTLY RAISED POPS IN THE
SOUTHWEST HALF OF THE AREA. SHORTWAVE TROUGH AND RIGHT REAR
QUADRANT OF JET ARE INCREASING THE COVERAGE OF STORMS FURTHER EAST
THAN WHAT WAS PREVIOUSLY DEPICTED. THE HRRR IS CATCHING THE HOURLY
TRENDS ON THE PRECIPITATION VERY WELL AND IS MIRRORED CLOSELY BY
THE 6 HOUR AMOUNTS SHOWN BY THE SREF AND ECMWF. THIS AREA MAKES
VERY GOOD SENSE CONSIDERING THE TRENDS AND THE LIFTING MECHANISMS.
SO FOLLOWED CLOSELY THOSE MODEL DEPICTIONS THROUGH THIS EVENING.
OTHERWISE...INCREASED CLOUD COVER SIGNIFICANTLY THROUGH THE
EVENING. WILL MONITOR TRENDS ON EVERYTHING ELSE THROUGH THE
EVENING. MESOSCALE AFFECTS WILL NO DOUBT WREAK HAVOC ON REMAINING
PARAMETERS THROUGH THE NIGHT.
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 140 PM MDT MON AUG 13 2012
UPPER FLOW WILL BE NORTHWEST TONIGHT/TUESDAY. A SHORTWAVE WILL COME
THROUGH THE FLOW TONIGHT. SUBSIDENCE WILL FOLLOW BEHIND THE WAVE ON
TUESDAY. SURFACE HIGH PRESSURE WILL BE OVER THE AREA TONIGHT. LOW
PRESSURE WILL BE OVER EASTERN WYOMING/NORTHEAST COLORADO TUESDAY.
DYNAMICS FROM THE INCOMING SHORTWAVE TONIGHT ARE SHOWN TO SLIDE
SOUTHEAST FROM EASTERN COLORADO INTO THE SOUTHERN FA. THIS IS WHERE
THE BEST MOISTURE IS AS WELL. PLAN TO GO WITH CHANCE POPS FOR THIS
AREA AND SLIGHT CHANCE POPS WHERE THERE IS LESS MOISTURE AND
FORCING. SUBSIDENCE WILL KEEP POPS NIL TUESDAY.
MIN TEMPERATURES TONIGHT WILL BE WARMER THAN LAST NIGHT AS COOLER
TEMPERATURES HAVE MOVED PAST THE FA AND SOUTH WINDS WILL MAINTAIN
GOOD MIXING OVERNIGHT. EXPECT READINGS IN THE UPPER 50S/LOWER 60S.
MAX TEMPERATURES TUESDAY WILL RISE INTO THE LOWER 90S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 250 PM MDT MON AUG 13 2012
THE FIRST SIGNIFICANT WEATHER FEATURE TO IMPACT THE AREA DURING
THIS PERIOD WILL BE A STRONG UPPER SHORT WAVE TROUGH NOW OVER
BRITISH COLUMBIA AS SEEN IN WATER VAPOR IMAGERY. THIS TROUGH WILL
MOVE SOUTHEAST AND SWEEP ACROSS THE C-N PLAINS WED-WED NIGHT. AT
THE SURFACE A STRONG COLD FRONT WILL MOVE RAPIDLY SOUTH ACROSS THE
FORECAST AREA WEDNESDAY EVENING AND WILL CLEAR THE AREA LATE
WEDNESDAY NIGHT. THESE FEATURES WILL GIVE AN OPPORTUNITY FOR
SHOWERS AND THUNDERSTORMS MAINLY WEDNESDAY NIGHT. MUCH COLDER AIR
WILL SETTLE INTO THE REGION FOR THURSDAY AND FRIDAY WITH HIGHS IN
THE UPPER 70S TO LOWER 80S.
BOTH THE EC AND GFS SUGGEST A MODERATELY STRONG NORTHWEST FLOW
ALOFT FOR THE REMAINDER OF THE WEEK AND THROUGH THE WEEKEND. THE
EC IS MOSTLY DRY WITH THIS PATTERN BUT THE GFS SUGGESTS THE
POTENTIAL FOR SEVERAL EPISODES OF PRECIPITATION. BOTH MODELS HINT
AT SEVERAL WEAK...FAST-MOVING SHORT WAVE TROUGHS SLIDING SOUTHEAST
THROUGH THE FLOW BUT TIMING WILL BE DIFFICULT. LOW POPS ARE
INCLUDED IN THE EXTENDED FORECAST AS A RESULT. ANY CONVECTION
WHICH INITIATES ON THE CHEYENNE RIDGE WOULD MOVE INTO THE
AREA...AIDED BY SOUTHEAST SURFACE FLOW WHICH WILL ENHANCE STORM
INFLOW TO KEEP CONVECTION GOING FOR A FEW HOURS BEFORE
DISSIPATION.
TEMPERATURES OVER THE WEEKEND WILL RETURN TO CLOSER TO NORMAL
VALUES BUT THE EXTREME HEAT HAS ABATED FOR AT LEAST THE NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 541 PM MDT MON AUG 13 2012
COMPLICATED SET OF TAFS ESPECIALLY FOR KGLD. EVEN WITH THE
THUNDERSTORMS IN PROGRESS...MODELS STILL NOT IN COMPLETE AGREEMENT
AS TO WHERE TO PUT THE PRECIPITATION. BASED ON LATEST TRENDS FROM
OBSERVATIONAL DATA...THE HRRR IS DOING THE BEST RIGHT AND DOES
BRING IN A CLUSTER OF STORMS THROUGH THE EVENING. SO HAVE INSERTED
THUNDERSTORMS ACROSS AT KGLD DURING THIS TIME. BASED ON WHAT HAVE
SEEN UPSTREAM...IT WILL BE POSSIBLE THAT MVFR VISIBILITIES WILL
OCCUR AT KGLD. MODELS INDICATING LOW CLOUDS AFTER 06Z AT KGLD.
WILL LET THE THUNDERSTORM SITUATION EVOLVE BEFORE BECOMING MORE
PESSIMISTIC BUT DID INSERT A SCATTERED LOW DECK. FOR KMCK IT LOOKS
LIKE THUNDERSTORMS WILL NOT AFFECT THE TAF SITE AT THIS TIME.
HOWEVER...WILL TO MONITOR TO MAKE ADJUSTMENTS AS NEEDED. IF NO
THUNDERSTORMS OCCUR AT KMCK...CONDITIONS WILL BE VFR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...FS
LONG TERM...DLF
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1130 PM CDT MON AUG 13 2012
.UPDATE...
ISSUED AT 1120 PM CDT MON AUG 13 2012
UPDATED FOR AVIATION SECTION ONLY.
UPDATE ISSUED AT 529 PM CDT MON AUG 13 2012
FROM A MESOSCALE PERSPECTIVE...THE CURRENT CONVECTION REMAINS IN A
QUASI-STEADY STATE. THE BEST THETA-E CONVERGENCE VIA LAPS DATA IS
BEING FOCUSED IN A ROUGHLY A 25 NAUTICAL MILE WIDE BAND ALONG THE
SURFACE FRONT...BUT WEST OF THE NORTH/SOUTH ORIENTED 2300 J2/K2
CAPE MAXIMUM ORIENTED NEAR INTERSTATE 55 IN SOUTHWEST ILLINOIS AND
SOUTHEAST MISSOURI. THE MAIN SURFACE LOW /WAVE/ IS OVER JACKSON
COUNTY ILLINOIS...AND WILL LIKELY MOVE NEAR MOUNT VERNON IN THE
NEXT COUPLE OF HOURS. UNFORTUNATELY...THE CORE OF THE HIGHER CAPE
VALUES HAS NOT BEEN PROGRESSING FURTHER NORTH...WHICH MAY LIMIT
UNCONDITIONAL SURFACE BASED INSTABILITY THROUGH THE EVENING.
THE HRRR AND 12KM NAM GUIDANCE APPEAR TO A HAVE A GENERAL IDEA OF
THE PROGRESSION OF THE FRONT AND OVERALL SYSTEM...BUT THE
PROJECTED FORECAST REFLECTIVITY GRIDS ARE ABOUT 80 TO 100 NM TOO
FAR TO THE SOUTHWEST. THE TIMING FOR SURFACE BASED CONVECTION WILL
BECOME MORE LIMITED THROUGH 00Z TUESDAY /7 PM CDT/ TONIGHT.
THERE IS A SUGGESTION IN THE 12KM NAM-WRF GUIDANCE THAT ENOUGH
FORECAST SHEAR /30-40KTS BULK SHEAR IN THE ZERO TO SIX KILOMETER
LAYER/ MOVING UP FROM EAST OF THE MISSISSIPPI RIVER IN WEST
TENNESSEE BETWEEN 23Z AND 02Z...THAT SOME MORE STORM DEVELOPMENT
AND ORGANIZATION MAY OCCUR TO SUSTAIN UPDRAFTS AS WEAK LOW LEVEL
WIND TRY TO INCREASE AT OR ABOVE THE DEVELOPING BOUNDARY LAYER
INVERSION AHEAD OF THE COLD FRONT. LOW LEVEL SHEAR IS QUITE
WEAK...SO ANY SUPPORT FOR RENEWED CONVECTION INTO WESTERN KENTUCKY
WILL HAVE TO COME FROM MID/UPPER LEVEL FORCING AND INSTABILITY.
THE KNQA VAD WIND PROFILE HAS BEEN SHOWING SOME INCREASE IN WINDS
NEAR 20KFT AS THE BASE OF THE UPPER WAVE. WHETHER THAT WILL BE
ENOUGH AS THE SHORTWAVE MOVES ACROSS WESTERN KY WILL BE THE 20
THOUSAND DOLLAR QUESTION.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 124 PM CDT MON AUG 13 2012
BOUNDARY AT 18Z WAS STILL OVER SOUTHEAST MISSOURI. AIR MASS
CONTINUES TO DESTABILIZE...WITH SOME ENHANCED CU SEEN NW OF
KCGI UP TOWARD PERRYVILLE MO. WILL CONTINUE TO MONITOR THIS
CORRIDOR AND POINTS EAST THROUGH THE AFTERNOON AND EARLY
EVENING FOR A FEW STRONG TO POSSIBLY SEVERE STORMS. OTHERWISE
THE ACTIVITY WILL PUSH EAST TONIGHT. QUIET WEATHER EXPECTED
TUESDAY AND TUESDAY NIGHT WITH VERY WEAK HIGH PRESSURE
FORECAST TO BUILD INTO THE AREA.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 124 PM CDT MON AUG 13 2012
BY WEDNESDAY...UPPER HEIGHTS BEGIN TO RISE ACROSS THE AREA AND THIS
SHOULD RESULT IN WARMER TEMPERATURES...BUT WE SHOULD REMAIN RIGHT
AROUND NORMAL. THE SFC HIGH THAT WILL BE OVER THE AREA ON WEDNESDAY
WILL CONTINUE PROGRESSING TO THE EAST AND BY WEDNESDAY NIGHT...OUR
AREA SHOULD BE IN SOUTHERLY FLOW...WITH A WARM FRONT DEVELOPING TO
OUR SOUTH THAT WILL INCH SLOWLY TO THE NORTH. HOWEVER...WE WILL
REMAIN DRY WEDNESDAY NIGHT.
BY 12Z THURSDAY...A COLD FRONT WILL STRETCH FROM THE GREAT LAKES TO
WEST TEXAS...AND BE MOVING EASTWARD ACROSS OUR AREA WITH TIME. BOTH
THE GFS AND ECMWF HAVE BEEN IN REALLY GOOD AGREEMENT WITH THE
PROGRESSION OF THIS FRONT. HOWEVER...THE GFS/ECMWF HAVE DEFINITELY
SLOWED DOWN EVEN MORE WITH THE ONSET OF PRECIP...AND ACTUALLY
INDICATE THAT MOST OF THURSDAY MIGHT END UP BEING FAIRLY DRY...WITH
OUR WESTERN SECTIONS HAVING THE BEST CHANCES BY LATER IN THE
AFTERNOON. THIS WILL MEAN THAT WE WILL PROBABLY SEE WARMER HIGHS ON
THURSDAY AS WELL. WITH HIGHS IN THE UPPER 80S/LOWER 90S AND
DEW POINTS IN THE UPPER 60S/LOWER 70S...IT WILL DEFINITELY FEEL LIKE
SUMMER IS BACK. SO...WILL KEEP WITH MIDNIGHT SHIFTS THOUGHT OF
BREAKING THE THURSDAY TIME PERIOD INTO TWO...SHOWING BETTER CHANCES
DURING THE AFTERNOON. THE BULK OF THE RAIN WILL ARRIVE ON THURSDAY
NIGHT AS THE FRONT PASSES THROUGH...SO WILL CONTINUE WITH LIKELY
POPS.
BY 12Z FRIDAY...BOTH THE GFS/ECMWF/GEM HAVE THE FRONTAL BOUNDARY IN
OUR EASTERN COUNTIES OR JUST EAST OF THE AREA. BELIEVE WE WILL SEE
THE POSSIBILITY OF PRECIPITATION LINGERING FRIDAY MORNING MAINLY IN
THE SOUTHEASTERN HALF OF THE CWA. COULD ALMOST GO DRY FOR FRIDAY
AFTERNOON...BUT WITH THE MODELS TRENDING SLOWER WITH THIS
FRONT...WILL FORGO THAT FOR NOW.
FRIDAY NIGHT APPEARS DRY ATTM...AS HIGH PRESSURE BUILDS INTO THE
AREA FROM CANADA. MUCH COOLER TEMPERATURES SHOULD RESULT AS 850 MB
TEMPS DIVE INTO THE LOW TEENS BY SATURDAY. THIS SHOULD RESULT IN
TEMPERATURES THAT ARE WELL BELOW NORMAL. GIVEN THE VERY DRY AIR THAT
WILL LIKELY FILTER INTO THE REGION...HIGH TEMPERATURES WILL PROBABLY
END UP BEING HIGHER THAN WHAT THE CURRENT GUIDANCE NUMBERS ARE
SUGGESTING. THE GFS AND ECMWF INDICATE AN INCREASE IN
MOISTURE/PRECIPITATION AS EARLY AS SATURDAY NIGHT AND INTO
SUNDAY...AS SOME ENERGY WRAPS AROUND AN UPPER LOW IN EASTERN CANADA
AND DIVES DOWN INTO OUR AREA. THE ECMWF APPEARS TO BE FASTER AND A
LITTLE MORE GUNG HO ON THIS IDEA...SHOWING A MORE PRONOUNCED TROUGH
SWINGING THROUGH. WITH CURRENT MODEL DIFFERENCES...WILL LEAVE THINGS
DRY FOR THE WEEKEND AND MONDAY...UNTIL WE CAN OBTAIN SOME BETTER
CONSISTENCY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1120 PM CDT MON AUG 13 2012
MAIN ISSUES WITH THE 06Z TAF WILL COME IN THE 1ST COUPLE HOURS WITH
LEFT OVER ISOLD/SCT CONVECTION NEAR/SOUTH OF KOWB. BELIEVE THUNDER
IS OVER ELSEWHERE...THO COULD BE AN ISOLD SHOWER NEAR KEVV IN THE
06-08 TIME FRAME.
NEXT CONCERN WILL BE WITH POSSIBLE DENSE FOG FORMATION WHERE HEAVY
RAIN WAS RECEIVED TODAY. THIS IS MAINLY FROM NEAR KCGI THROUGH THE
KPAH SITE. HPAH RECEIVED OVER AN INCH OF RAIN THIS EVENING...AND
IS ALREADY MVFR AT 04Z. THIS SITE WILL LIKELY STAND THE HIGHEST
CHANCES OF TANKING DOWN TO IFR/LOW IFR IN THE 06-12Z TIME FRAME.
HOWEVER...LIGHT NW WINDS ARE JUST TO THE WEST...AND IF THESE
WINDS BREAK IN THROUGH THE INVERSION...THE FOG WOULD DISSIPATE.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...MEFFERT
AVIATION...MEFFERT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
624 PM EDT TUE AUG 14 2012
.SYNOPSIS...
A WEAK RIDGE OF HIGH PRESSURE OVER THE AREA WILL MOVE EAST OF THE
REGION TONIGHT. A TROUGH OF LOW PRESSURE WILL APPROACH LATER
TONIGHT...THEN SLOWLY CROSS THE REGION WEDNESDAY THROUGH
THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
UPDATE...ADJUSTED THE POPS AND SKY TO MATCH UP BETTER W/THE LATEST
CONDITIONS AND RADAR. THE NAM12 AND CANADIAN REGGIE DOING WELL
W/THE SKY AND HRRR ALONG W/THE NAM12 HANDLING THE SHOWERS/TSTMS
WELL. KEPT 40% IN THE AREAS W/THE HEAVIEST CONCENTRATION AND 20%
FOR THE SPOTTY SHOWERS. LATS LAPS SOUNDINGS SUPPORT ENOUGH
INSTABILITY FOR TSTMS TO KEEP GOING INTO THE EARLY EVENING.
ADDED FOG FOR LATE TONIGHT ESPECIALLY ACROSS THE NORTHERN 1/2 OF
THE CWA. NAM/GFS SOUNDINGS SUPPORT THIS AS AIRMASS COOLS
OVERNIGHT. HRLY TEMPERATURES WERE TWEAKED TO MATCH THE LATEST
TRENDS WHICH POINT TO WARMER READINGS INITIALLY.
PREVIOUS DISCUSSION...
ANY SCATTERED SHOWERS OR ISOLATED THUNDERSTORMS THROUGH LATE
AFTERNOON WILL DISSIPATE WITH THE LOSE OF HEATING. CLOUDS WILL
BEGIN TO INCREASE LATER TONIGHT IN ADVANCE OF AN APPROACHING
TROUGH FROM THE WEST. LOWS TONIGHT WILL RANGE FROM THE UPPER 50S
TO LOWER 60S.
EXPECT MOSTLY CLOUDY SKIES ON WEDNESDAY WITH SHOWERS AND
THUNDERSTORMS AS THE TROUGH OF LOW PRESSURE MOVES EAST. HIGHS ON
WEDNESDAY WILL RANGE FROM THE MID TO UPPER 70S ACROSS THE REGION.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
WHATS LEFT OF THE FIRST ROUND OF CNVCTN FROM WED AFTN SHOULD BE
EXITING THE FA VIA NB PROV WED EVE AS THE UPPER S/WV MOVES E.
A SECOND S/WV FROM THE GREAT LAKE WITH ANOTHER ROUND OF SHWRS WILL
APCH WRN PTNS OF THE FA LATE WED NGT/THU MORN WITH PATCHY FOG...THEN
CROSS THE REST OF THE REGION MIDDAY THRU THU AFTN. WE DID INDICATE
A CHC OF THUNDER WITH LIKELY AND GREATER POPS THU AFTN AND ERLY
EVE...BUT WITH LITTLE IF ANY SUNSHINE XPCTD OVR THE REGION...WE DO
NOT XPCT MUCH IN THE WAY OF SB CAPE AND STRONG TSTMS DURG THIS TM.
MAX POPS REACH 80 PERCENT WITH THIS ROUND BASED ON BLENDED MODEL
QPF...BUT FOR NOW...WE CANNOT IDENTIFY ANY 6 HRLY QPF PD
INDICATING MUCH ABV 0.25 INCHES OF RNFL ATTM...SO MENTION OF HVY
RNFL TO GRIDS ATTM.
SHWRS SHOULD END W TO E AS THEY MOVE E AGAIN INTO NB LATE THU NGT
WITH THE LIFTING OUT OF THE UPPER TROF. THERE APPEARS TO BE A
BREAK FRI MORN WITH POSSIBLE SUNSHINE PRIOR TO A THE ARRIVAL OF
A FAIRLY STRONGER COLD FRONT TO NWRN ME BY FRI EVE FROM CNTRL CAN
AS LARGE MID/UPPER VORTEX SETTLES ESE NEAR HUDSON BAY. FOR NOW...
WE BRING POPS UP TO HI CHC RANGE FOR TSTMS MSLY NRN/WRN PTNS OF
FA BY LATE FRI AFTN...GIVEN THAT SUNSHINE FRI MORN WILL INTRODUCE
SOME SB CAPE TO FCST SOUNDINGS FRI AFTN.
AFT A LITTLE ABV AVG LOWS WED NGT...HI TEMPS THU WILL DEFINITELY
BE HELD DOWN TO BLO NORMAL BY CLD CVR AND SHWRS...WITH HI TEMPS
FRI CLOSE TO OR SLIGHTLY ABV NORMAL AFT NEAR NORMAL LOW THU NGT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A COLD FRONT PASSES TO THE EAST OF THE AREA AT THE BEGINING OF
THIS PERIOD THEN HIGH PRESSURE WILL BUILD IN FROM THE WEST AND
CREST OVER THE AREA SUNDAY. UPPER TROUGH THEN APPROACHES FROM THE
GREAT LAKES MONDAY. THIS SYSTEM WILL MOVE ACROSS THE REGION
TUESDAY. HAVE USED THE GMOS TO INITIALIZE GRIDS. WILL ADJUST POP
AND SKY COVER GRIDS.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
NEAR TERM: MAINLY VFR THROUGH TONIGHT. THE EXCEPTION WILL BE IN
ANY PATCHY FOG LATER TONIGHT WHICH COULD RESULT IN LOCALIZED
MVFR/IFR VSBYS. CONDITIONS SHOULD BE MAINLY VFR WEDNESDAY BUT
COULD DETERIORATE TO MVFR DURING WEDNESDAY AFTERNOON IN
SHOWERS/TSTMS.
SHORT TERM: MSLY IFR WED NGT AND MVFR THU AND THU EVE ALL TAF
SITES DUE TO SHWRS AND PATCHY FOG...IMPRVG TO VFR LATE THU NGT
INTO FRI MORN. MVFR WILL AGAIN BE POSSIBLE FRI AFTN NRN TAF SITES
WITH ANY TSTM. EXPECT MVFR CONDITIONS LATE FRIDAY NIGHT INTO
SUNDAY.
&&
.MARINE...
NEAR TERM: WINDS/SEAS WILL REMAIN BELOW SCA LEVELS THROUGH WEDNESDAY.
SHORT TERM: NO HDLNS XPCTD WITH RELATIVELY LGT WINDS AND LITTLE
SWELL COMPONENT WITH WV HTS. KEPT CLOSE TO WW3 WV HTS OVR OUTER
MZS...LOWERED TO ARND 1 FT ALG THE IMMEDIATE COAST...INNER HARBORS/
BAYS. PATCHY MARINE FOG MAY ALSO OCCUR LATE WED NGT INTO THU MORN IN
CONJUNCTION WITH RN SHWRS AS SFC DWPTS RISE ABV SSTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DUDA/HEWITT
SHORT TERM...VJN
LONG TERM...MIGNONE
AVIATION...DUDA/HEWITT
MARINE...DUDA/HEWITT/VJN
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
636 AM EDT TUE AUG 14 2012
.SYNOPSIS...
LOW PRESSURE, COMING EAST FROM INDIANA, WILL BRING SHOWERS AND
SCATTERED THUNDERSTORMS ACROSS THE UPPER OHIO VALLEY UNTIL THE
LOW PASSES THROUGH THIS EVENING. HIGH PRESSURE FROM IOWA WILL
FOLLOW WITH DRY SEASONABLE CONDITIONS WEDNESDAY AND THURSDAY. A
COLD FRONT, COMING SOUTHEAST FROM MONTANA, WILL PROVIDE THE NEXT
ROUND OF SHOWERS AND THUNDERSTORMS FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HAVE ADJUSTED SHOWER CHANCES FOR THE EARLY MORNING. BASED ON
RECENT RADAR AND SURFACE DATA PLUS HRRR MODEL OUTPUT, THE FIRST
BATCH OF ISOLATED SHOWERS HAS EXITED EAST OF THE MOUNTAINS. HAVE
ADDED ISOLATED FOG PATCHES THROUGH 9 AM.
BLEND OF RECENT WRF-NMM, HRRR, AND SREF MODEL OUTPUT THEN SHOW
CURRENT RADAR-DEPICTED SHOWERS AND ISOLATED THUNDERSTORMS OVER
WESTERN OHIO, WILL INCREASE IN COVERAGE LATER THIS MORNING AND
THROUGH THE AFTERNOON, AS THEY SPREAD EASTWARD AHEAD OF THE LOW
PRESSURE CENTER, MOVING EAST FROM INDIANA.
HAVE LOW EXPECTATIONS REGARDING SEVERE POTENTIAL, AS NAM-MODEL
PROFILES AND MOST SREF MODEL MEMBERS SHOW INSTABILITY ACROSS THE
UPPER OHIO VALLEY WILL LIMITED BY THICKENING CLOUDS THIS MORNING.
THERE WILL BE MORE INSTABILITY AND HENCE MORE SEVERE POTENTIAL
EAST OF THE MOUNTAINS.
THIS SCENARIO IS FORTUNATE FOR THE UPPER OHIO VALLEY AS VERTICAL
WIND SHEAR, THAT IS, EFFECTIVE BULK SHEARS OF 30 PLUS KNOTS, WOULD
HAVE BEEN SUFFICIENT TO ORGANIZE RISING AIR COLUMNS INTO PRODUCING
SEVERE POTENTIAL.
AS LOW PRESSURE SYSTEM EXITS EAST TONIGHT, SHOWERS WILL END WEST
TO EAST LATE. DUE TO NOCTURNAL-COOLING OF A RAIN-MOISTENED SURFACE
LAYER, PATCHY FOG CAN DEVELOP.
FORECASTED TEMPERATURES TO BE SLIGHTLY COOLER THAN NORMAL TODAY,
THEN NEAR NORMAL TONIGHT, AS INDICATED BY RECENT GFS AND NAM MOS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
BLEND OF SREF AND GFS MODEL OUTPUT SHOW HIGH PRESSURE COMING EAST
FROM IOWA WILL PROVIDE DRYING AND SUBSIDENCE ACROSS THE UPPER OHIO
VALLEY WEDNESDAY AND THURSDAY. DO REALIZE THERE WILL BE A TRAILING
TROUGH ALOFT WEDNESDAY THAT COULD SET OFF ISOLATED SHOWERS, BUT
CONCUR WITH GFS AND NAM MOS THAT PROBABILITIES WILL BE TOO LOW TO
MENTION.
A STRONGER LOW PRESSURE SYSTEM WILL MOVE EASTWARD ACROSS SOUTHERN
CANADA DURING THIS PERIOD, WHICH WILL PUSH A COLD FRONT THROUGH
THE UPPER OHIO VALLEY FRIDAY. SO HAVE ADDED A CHANCE OF SHOWERS
AND THUNDERSTORMS LATE THURSDAY NIGHT AND FRIDAY.
FORECASTED TEMPERATURES TO BE NEAR SEASONABLE LEVELS BASED ON
RECENT GFS AND NAM MOS AND SREF MEAN VALUES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
POST-COLD FRONTAL 850 TEMPS OF 6-7C, WITH A COLD TROUGH ALOFT
PASSING THROUGH THE UPPER OHIO VALLEY, MAY CONTINUE CLOUDS AND
SCATTERED SHOWERS THROUGH DAYTIME SATURDAY. FORECASTED
TEMPERATURES TO BE ABOUT 5 DEGREES COOLER THAN NORMAL.
ENSUING HIGH PRESSURE WILL PROVIDE DRY BUT COOLER THAN NORMAL
TEMPERATURES SUNDAY AND MONDAY, JUDGING FROM RECENT GFS AND ECMWF
MOS.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
ISOLATED FOG PATCHES CAN PROVIDE MVFR VISIBILITIES THROUGH 13Z.
THEN VFR CONDITIONS WILL PERSIST UNTIL RAIN SHOWERS AND
SCATTERED THUNDERSTORMS SPREAD EASTWARD AHEAD OF THE LOW
PRESSURE SYSTEM, THAT WILL CROSS THE REGION LATE THIS AFTERNOON,
AND EXIT EAST EARLY TONIGHT. MVFR CIGS AND VIS CAN BE EXPECTED
ESPECIALLY IN ANY THUNDERSTORMS BUT WITH LIMITED CONFIDENCE IN
TSRA COVERAGE AT THIS POINT WILL LEAVE IT OUT OF TAFS.
PATCHES OF FOG, WITH MAINLY MVFR RESTRICTIONS, CAN DEVELOP
TONIGHT DUE TO NOCTURNAL COOLING OF A RAIN-MOISTENED SURFACE
LAYER. THE DEGREE TO WHICH RESTRICTIONS WILL DEVELOP WILL BE
HIGHLY DEPENDENT ON AMOUNT OF RAINFALL THAT ACTUALLY OCCURS
TODAY.
.OUTLOOK...WEDNESDAY THROUGH SATURDAY...
EXPECT VFR WEDNESDAY AND THURSDAY DUE TO PASSING HIGH PRESSURE.
THE NEXT POSSIBILITY OF RESTRICTIONS WILL BE FRIDAY INTO SATURDAY
DUE TO SHOWERS AND STORMS ASSOCIATED WITH A COLD FRONTAL PASSAGE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
559 AM EDT TUE AUG 14 2012
.SYNOPSIS...
LOW PRESSURE, COMING EAST FROM INDIANA, WILL BRING SHOWERS AND
SCATTERED THUNDERSTORMS ACROSS THE UPPER OHIO VALLEY UNTIL THE
LOW PASSES THROUGH TUESDAY EVENING. HIGH PRESSURE FROM IOWA WILL
FOLLOW WITH DRY SEASONABLE CONDITIONS WEDNESDAY AND THURSDAY. A
COLD FRONT, COMING SOUTHEAST FROM MONTANA, WILL PROVIDE THE NEXT
ROUND OF SHOWERS AND THUNDERSTORMS FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HAVE ADJUSTED SHOWER CHANCES FOR THE EARLY THIS MORNING. BASED ON
RECENT RADAR AND SURFACE DATA PLUS HRRR MODEL OUTPUT, THE FIRST
BATCH OF ISOLATED SHOWERS HAS EXITED EAST OF THE MOUNTAINS. HAVE
ADDED ISOLATED FOG PATCHES THROUGH 9 AM.
BLEND OF RECENT WRF-NMM, HRRR, AND SREF MODEL OUTPUT THEN SHOW
CURRENT RADAR-DEPICTED SHOWERS AND ISOLATED THUNDERSTORMS OVER
WESTERN OHIO, WILL INCREASE IN COVERAGE LATER THIS MORNING AND
THROUGH THE AFTERNOON, AS THEY SPREAD EASTWARD AHEAD OF THE LOW
PRESSURE CENTER, MOVING EAST FROM INDIANA.
HAVE LOW EXPECTATIONS REGARDING SEVERE POTENTIAL, AS NAM-MODEL
PROFILES AND MOST SREF MODEL MEMBERS SHOW INSTABILITY ACROSS THE
UPPER OHIO VALLEY WILL LIMITED BY THICKENING CLOUDS THIS MORNING.
THERE WILL BE MORE INSTABILITY AND HENCE MORE SEVERE POTENTIAL
EAST OF THE MOUNTAINS.
THIS SCENARIO IS FORTUNATE FOR THE UPPER OHIO VALLEY AS VERTICAL
WIND SHEAR, THAT IS, EFFECTIVE BULK SHEARS OF 30 PLUS KNOTS, WOULD
HAVE BEEN SUFFICIENT TO ORGANIZE RISING AIR COLUMNS INTO PRODUCING
SEVERE POTENTIAL.
AS LOW PRESSURE SYSTEM EXITS EAST TONIGHT, SHOWERS WILL END WEST
TO EAST LATE. DUE TO NOCTURNAL-COOLING OF A RAIN-MOISTENED SURFACE
LAYER, PATCHY FOG CAN DEVELOP.
FORECASTED TEMPERATURES TO BE SLIGHTLY COOLER THAN NORMAL TODAY,
THEN NEAR NORMAL TONIGHT, AS INDICATED BY RECENT GFS AND NAM MOS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
BLEND OF SREF AND GFS MODEL OUTPUT SHOW HIGH PRESSURE COMING EAST
FROM IOWA WILL PROVIDE DRYING AND SUBSIDENCE ACROSS THE UPPER OHIO
VALLEY WEDNESDAY AND THURSDAY. DO REALIZE THERE WILL BE A TRAILING
TROUGH ALOFT WEDNESDAY THAT COULD SET OFF ISOLATED SHOWERS, BUT
CONCUR WITH GFS AND NAM MOS THAT PROBABILITIES WILL BE TOO LOW TO
MENTION.
A STRONGER LOW PRESSURE SYSTEM WILL MOVE EASTWARD ACROSS SOUTHERN
CANADA DURING THIS PERIOD, WHICH WILL PUSH A COLD FRONT THROUGH
THE UPPER OHIO VALLEY FRIDAY. SO HAVE ADDED A CHANCE OF SHOWERS
AND THUNDERSTORMS LATE THURSDAY NIGHT AND FRIDAY.
FORECASTED TEMPERATURES TO BE NEAR SEASONABLE LEVELS BASED ON
RECENT GFS AND NAM MOS AND SREF MEAN VALUES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
POST-COLD FRONTAL 850 TEMPS OF 6-7C, WITH A COLD TROUGH ALOFT
PASSING THROUGH THE UPPER OHIO VALLEY, MAY CONTINUE CLOUDS AND
SCATTERED SHOWERS THROUGH DAYTIME SATURDAY. FORECASTED
TEMPERATURES TO BE ABOUT 5 DEGREES COOLER THAN NORMAL.
ENSUING HIGH PRESSURE WILL PROVIDE DRY BUT COOLER THAN NORMAL
TEMPERATURES SUNDAY AND MONDAY, JUDGING FROM RECENT GFS AND ECMWF
MOS.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
ISOLATED FOG PATCHES CAN PROVIDE MVFR VISIBILITIES THROUGH 13Z.
THEN VFR CONDITIONS WILL PERSIST UNTIL RAIN SHOWERS AND
SCATTERED THUNDERSTORMS SPREAD EASTWARD AHEAD OF THE LOW
PRESSURE SYSTEM, THAT WILL CROSS THE REGION LATE THIS AFTERNOON,
AND EXIT EAST EARLY TONIGHT. MVFR CIGS AND VIS CAN BE EXPECTED
ESPECIALLY IN ANY THUNDERSTORMS BUT WITH LIMITED CONFIDENCE IN
TSRA COVERAGE AT THIS POINT WILL LEAVE IT OUT OF TAFS.
PATCHES OF FOG, WITH MAINLY MVFR RESTRICTIONS, CAN DEVELOP TONIGHT DUE TO
NOCTURNAL COOLING OF A RAIN-MOISTENED SURFACE LAYER.
.OUTLOOK...WEDNESDAY THROUGH SATURDAY...
EXPECT VFR WEDNESDAY AND THURSDAY DUE TO PASSING HIGH PRESSURE.
THE NEXT POSSIBILITY OF RESTRICTIONS WILL BE FRIDAY INTO SATURDAY
DUE TO SHOWERS AND STORMS ASSOCIATED WITH A COLD FRONTAL PASSAGE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
457 AM EDT TUE AUG 14 2012
.SYNOPSIS...
LOW PRESSURE, COMING EAST FROM INDIANA, WILL BRING SHOWERS ACROSS THE
UPPER OHIO VALLEY UNTIL THE LOW PASSES THROUGH TUESDAY EVENING.
HIGH PRESSURE FROM IOWA WILL FOLLOW WITH DRY SEASONABLE CONDITIONS
WEDNESDAY AND THURSDAY. A COLD FRONT, COMING SOUTHEAST FROM
MONTANA, WILL PROVIDE THE NEXT ROUND OF SHOWERS AND THUNDERSTORMS
FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HAVE AGAIN ADJUSTED SHOWER CHANCES FOR THE EARLY MORNING TO NO MORE
THAN ISOLATED COVERAGE, BASED ON RECENT RADAR AND SURFACE DATA
PLUS HRRR MODEL OUTPUT.
BLEND OF RECENT WRF-NMM, HRRR, AND SREF MODEL OUTPUT THEN SHOW
CURRENT RADAR-DEPICTED SHOWERS AND ISOLATED THUNDERSTORMS OVER
WESTERN OHIO, WILL INCREASE IN COVERAGE LATER THIS MORNING AND
THROUGH THE AFTERNOON, AS THEY SPREAD EASTWARD AHEAD OF THE LOW
PRESSURE CENTER, MOVING EAST FROM INDIANA.
HAVE LOW EXPECTATIONS REGARDING SEVERE POTENTIAL, AS NAM-MODEL
PROFILES AND MOST SREF MODEL MEMBERS SHOW INSTABILITY ACROSS THE
UPPER OHIO VALLEY WILL LIMITED BY THICKENING CLOUDS THIS MORNING.
THERE WILL BE MORE INSTABILITY AND HENCE MORE SEVERE POTENTIAL
EAST OF THE MOUNTAINS.
THIS IS FORTUNATE FOR THE UPPER OHIO VALLEY AS VERTICAL WIND
SHEAR, EFFECTIVE BULK SHEARS OF 30 PLUS KNOTS, WOULD HAVE BEEN
SUFFICIENT TO ORGANIZE RISING AIR COLUMNS INTO PRODUCING SEVERE
POTENTIAL.
AS LOW PRESSURE SYSTEM EXITS EAST TONIGHT, SHOWERS WILL END WEST
TO EAST LATE. DUE TO NOCTURNAL-COOLING OF A RAIN-MOISTENED SURFACE
LAYER, PATCHY FOG CAN DEVELOP.
FORECASTED TEMPERATURES TO BE SLIGHTLY COOLER THAN NORMAL TODAY,
THEN NEAR NORMAL TONIGHT, AS INDICATED BY RECENT GFS AND NAM MOS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
BLEND OF SREF AND GFS MODEL OUTPUT SHOW HIGH PRESSURE COMING EAST
FROM IOWA WILL PROVIDE DRYING AND SUBSIDENCE ACROSS THE UPPER OHIO
VALLEY WEDNESDAY AND THURSDAY. DO REALIZE THERE WILL BE A TRAILING
TROUGH ALOFT WEDNESDAY THAT COULD SET OFF ISOLATED SHOWERS, BUT
CONCUR WITH GFS AND NAM MOS THAT PROBABILITIES WILL BE TOO LOW TO
MENTION.
A STRONGER LOW PRESSURE SYSTEM WILL MOVE EASTWARD ACROSS SOUTHERN
CANADA DURING THIS PERIOD, WHICH WILL PUSH A COLD FRONT THROUGH
THE UPPER OHIO VALLEY FRIDAY. SO HAVE ADDED A CHANCE OF SHOWERS
AND THUNDERSTORMS LATE THURSDAY NIGHT AND FRIDAY.
FORECASTED TEMPERATURES TO BE NEAR SEASONABLE LEVELS BASED ON
RECENT GFS AND NAM MOS AND SREF MEAN VALUES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
POST-COLD FRONTAL 850 TEMPS OF 6-7C, WITH A COLD TROUGH ALOFT
PASSING THROUGH THE UPPER OHIO VALLEY, MAY CONTINUE CLOUDS AND
SCATTERED SHOWERS THROUGH DAYTIME SATURDAY. FORECASTED
TEMPERATURES TO BE ABOUT 5 DEGREES COOLER THAN NORMAL.
ENSUING HIGH PRESSURE WILL PROVIDE DRY BUT COOLER THAN NORMAL
TEMPERATURES SUNDAY AND MONDAY, JUDGING FROM RECENT GFS AND ECMWF
MOS.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL CONTINUE UNTIL HEAVIER RAIN SHOWERS AND
THUNDERSTORMS SPREAD EASTWARD AHEAD OF THE LOW PRESSURE SYSTEM
THAT WILL CROSS THE REGION LATE THIS AFTERNOON. MVFR CIGS AND VIS
CAN BE EXPECTED ESPECIALLY IN ANY THUNDERSTORMS BUT WITH LIMITED
CONFIDENCE IN TSRA COVERAGE AT THIS POINT WILL LEAVE IT OUT OF
TAFS.
.OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
MVFR/IFR CONDITIONS IN STRATUS/FOG COULD BE POSSIBLE BEHIND THE
FRONT TUESDAY NIGHT. VFR CONDITIONS SHOULD THEN RETURN FOR
WEDNESDAY AND THURSDAY DUE TO PASSING HIGH PRESSURE. THE NEXT
POSSIBILITY OF RESTRICTIONS WILL BE FRIDAY INTO SATURDAY DUE TO
SHOWERS AND STORMS ASSOCIATED WITH A COLD FRONTAL PASSAGE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
844 PM EDT WED AUG 15 2012
.UPDATE...
ISSUED AT 842 PM EDT WED AUG 15 2012
TENDED TO SLOW DOWN EWD PROGRESSION OF SHRA/TS NOW IN MN INTO WRN
UPR MI WITH LLVL SE FLOW TENDING TO MAINTAIN DRY LLVL AIR SHOWN ON
THE 00Z APX RAOB OVER THE CWA. THE 12Z CNDN MODEL APPEARS TO HAVE
THE BEST HANDLE ON THIS SLOWER EWD PROGRESSION. EVEN THOUGH VIGOROUS
DYNAMICS ASSOCIATED WITH POTENT SHRTWV MOVING E THRU THE NRN PLAINS
ARE ACTING ON THIS LINE OF SHRA/TS DURING PEAK HEATING TIME...SVR
STORMS HAVE BEEN FEW AND FAR BTWN IN MN. SINCE MODELS SHOW WEAKER
MUCAPES IN THE 400-800 J/KG RANGE OVER THE CWA TNGT...SVR THREAT
SEEMS LO. DESPITE THE PRESENCE OF THIS LARGER SCALE DRY LLVL
AIR...THE 00Z GRB RAOB SHOWS AN AREA OF HIER MID LVL MSTR WITH KINX
OF 33. RADAR SHOWS SOME ISOLD -SHRA OVER NE WI MOVING TOWARD MNM
COUNTY AND HIER MUCAPE OVER THE SE CWA SHOWN ON THE SPC
MESOANALYSIS. SO INTRODUCED SOME ISOLD SHRA/TS OVER THE SE ZNS THRU
06Z. MAINTAINED THE INCRSG POPS LATER TNGT OVER THE CNTRL ZNS AS THE
CNDN MODEL SHOWS HIER QPF AFT 09Z AS DYNAMICS INTERACT WITH MORE
ABUNDANT MID LVL MSTR SHOWN ON THE GRB RAOB AND WSHFT TO THE SW
AHEAD OF APRCHG COLD FNT MIGHT ALLOW MORE LLVL MSTR TO ARRIVE.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 425 PM EDT WED AUG 15 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A POSITIVE TILT MID/UPPER
LEVEL TROUGH FROM NRN MANITOBA INTO ERN MT WITH A DOWNSTREAM RIDGE
FROM THE WRN GREAT LAKES INTO NRN ONTARIO. AT THE SFC...A COLD FRONT
EXTENDED THROUGH THE ERN DAKOTAS FROM LOW PRES OVER SE MANITOBA.
LIGHT SHOWERS OVER WRN WI THAT HAD DEVELOPED WITH WAA/305-310K
ISENTROPIC LIFT HAD DISSIPATED AS THEY MOVED INTO DRIER AIR TO THE
EAST...LEAVING MAINLY JUST BKN MID CLOUDS UPSTREAM OVER NW WI. SCT
SHRA/TSRA HAD ALSO DEVELOPED AHEAD OF THE FRONT OVER NW MN.
TONIGHT AND THURSDAY...EVEN THOUGH THE NAM/RUC SEEM OVERDONE WITH
THE AMOUNT OF WAA PCPN INTO THE AREA LATE THIS AFTERNOON AND
EVENING...COMPARED TO CURRENT TRENDS...CANNOT RULE OUT SOME LIGHT
SHOWERS DEVELOPING OVER THE WEST THIS EVENING WHERE SLIGHT CHANCE
POPS WERE RETAINED. OTHERWISE...MORE WIDESPREAD PCPN SHOULD MOVE
INTO THE CWA...MAINLY AFT 06Z AS THE MODELS HAVE TRENDED TOWARD A
SLOWER ARRIVAL OF GREATEST SHRA/TSRA CHANCES. FAVORABLE DYNAMICS
WITH 700-300 MB QVECTOR CONV AHEAD OF THE MID LEVEL TROUGH AND LOW
LEVEL CONV WITH THE FRONT SHOULD SUPPORT CATEGORICAL POPS LATE
TONIGHT INTO THURSDAY MORNING. THE SHRA/TSRA SHOULD EXIT CNTRL UPPER
MI IN THE MORNING AND THE ERN CWA DURING THE EARLY AFTERNOON. THERE
IS LESS CONFIDENCE WITH POTENTIAL FOR HIGHER PCPN AMOUNTS OR SEVERE
WEATHER AS THE GREATER MOISTURE INFLOW AND INSTABILITY WILL REMAIN
FARTHER SOUTH OVER WI.
STRENGTHENING WIND FIELDS WITH 0-6KM SHEAR VALUES INTO THE 30-35 KT
ARE EXPECTED AS THE SHRA/TSRA ARRIVES BUT MAY LAG THE BEST LOW LEVEL
FORCING. NEVERTHELESS THERE IS LIMITED SVR POTENTIAL WITH MUCAPE
VALUES FCST INTO THE 500-1000 J/KG RANGE. IF STRONGER LINEAR
CONVECTIVE AREAS SURVIVE AS THEY MOVE OUT OF MN AND NW WI...SOME
DAMAGING WIND GUSTS MAY BE POSSIBLE AS THE MAIN HAZARD...PER SPC.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 425 PM EDT WED AUG 15 2012
TEMPERATURES THROUGH THE EXTENDED WILL REMAIN BELOW NORMAL WITH A
WARMING TREND BEGINNING LATE IN THE PERIOD.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...THE UPPER LEVEL AND SURFACE
LOW WILL BECOME VERTICALLY STACKED THURSDAY NIGHT INTO FRIDAY AS THE
LOW SHIFTS FROM CENTRAL ONTARIO NORTH AND EASTWARD TO JAMES BAY. AS
THIS HAPPENS THE UPPER LEVEL TROUGH AXIS WILL SWING ACROSS UPPER
MICHIGAN. THE COOLER AIR ALOFT ASSOCIATED WITH THIS TROUGH WILL HELP
TO CREATE CONDITIONS FAVORABLE FOR LAKE EFFECT RAIN SHOWERS ACROSS
MAINLY CENTRAL PORTIONS OF UPPER MICHIGAN. H850 TEMPS ARE PROGGED TO
BE AROUND 4 TO 6C WITH SURFACE TEMPS AROUND 18 TO 19C ACROSS THE
AREA...WHICH SHOULD CREATE A LARGE ENOUGH TEMPERATURE DIFFERENCE TO
CAUSE THE LAKE EFFECT RAIN SHOWERS TO FORM. ALONG WITH THE RAIN
SHOWERS...HIGH WINDS ARE ALSO POSSIBLE OVER THE LAKE THURSDAY
AFTERNOON INTO THURSDAY NIGHT AS 30 TO 35 KNOT WINDS...AS SHOWN BY
THE EC/GFS...MIX DOWN TO THE LAKE SURFACE. AS THE UPPER LEVEL LOW
SHIFTS NORTHEASTWARD AND THE UPPER LEVEL TROUGH AXIS SHIFTS PAST THE
UPPER PENINSULA FRIDAY NIGHT...H850 TEMPS ARE EXPECTED TO
WARM...EFFECTIVELY REDUCING THE LAKE EFFECT RAIN SHOWER CHANCES. A
COOL NIGHT IS IN STORE FOR FRIDAY NIGHT AS WINDS BECOME LIGHT AND
SKIES BECOME MOSTLY CLEAR. TEMPERATURES AREA EXPECTED TO BE IN THE
LOW TO MID 40S ACROSS MAINLY INLAND AREAS...WITH A FEW OF THE USUAL
COOL SPOTS POTENTIALLY FALLING INTO THE UPPER 30S.
SATURDAY THROUGH MONDAY...A WEAK COLD FRONT WILL PUSH SOUTHWARD INTO
THE U.P. SATURDAY AFTERNOON THROUGH SUNDAY. A 500MB SHORTWAVE IS
ALSO PROGGED TO MOVE THROUGH THE AREA SATURDAY NIGHT THROUGH
MONDAY...AS IT ROTATES AROUND THE LOW CENTERED OVER JAMES BAY. THIS
SHOULD PROVIDE ENOUGH FORCING FOR A FEW SHOWERS TO DEVELOP THROUGH
THIS TIME PERIOD...HOWEVER...MOISTURE SHOULD BE FAIRLY LIMITED AS A
SURFACE HIGH PRESSURE SYSTEM WILL REMAIN CENTERED TO THE SOUTH
SOUTHWEST OF THE AREA KEEPING DRIER AIR ADVECTING INTO THE AREA FROM
THE WEST.
MONDAY NIGHT THROUGH WEDNESDAY...AS THE UPPER LEVEL LOW BEGINS TO
DRIFT SLOWLY EASTWARD...A RIDGE BUILDING OVER MUCH OF THE PLAINS
STATES WILL BEGIN TO WEAKEN AS IT TRIES TO BUILD EASTWARD INTO THE
UPPER GREAT LAKES REGION. THIS SHOULD ALLOW TEMPERATURES TO INCREASE
TO NEAR NORMAL LEVELS BY TUESDAY AND INTO THE DAY WEDNESDAY. TUESDAY
NIGHT INTO WEDNESDAY BOTH THE GFS/EC HAVE A SHORTWAVE ROTATING
AROUND THE RIDGE ALONG WITH A SURFACE LOW JUST TO THE WEST OF THE
REGION...BRINGING THE NEXT CHANCE OF SHOWERS TO THE AREA.
HOWEVER...WITH CONSIDERABLE DIFFERENCES IN SURFACE LOW PLACEMENT AND
STRENGTH HAVE DECIDED TO STICK TO A CONSENSUS OF THE MODELS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 722 PM EDT WED AUG 15 2012
EXPECT VFR CONDITIONS THRU THIS EVNG AT ALL 3 TAF SITES WITH SSE
TRAJECTORIES MAINTAINING SOME DRY LLVL AIR. THE APRCH OF A COLD FNT
LATER WL BRING THE THREAT OF TS TO AT LEAST IWD BY 06Z. BUT THESE
STORMS ARE LIKELY TO WEAKEN BEFORE REACHING CMX AND ESPECIALLY SAW
TOWARD 09Z. FOLLOWING THE FROPA...A WSHFT TO THE WNW WL ADVECT
COOLER AND MOISTER LLVL AIR INTO THE AREA...RESULTING IN LO CLDS/
MVFR CONDITIONS AND STRENGTHENING WINDS. THE BEST CHC FOR IFR
CONDITIONS AND STRONGER WINDS WL BE AT THE MORE EXPOSED CMX SITE
WITH A MORE PRONOUNCED UPSLOPE WIND COMPONENT. EXPECT THESE LO CIGS
TO SLOWLY LIFT DURING THE DAY...BUT MVFR CIGS MAY LINGER ALL DAY AT
CMX...WHERE WIND GUSTS MAY APRCH 35 KTS WITH THE APRCH OF AXIS OF
COOLEST AIR/MORE INSTABILITY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 425 PM EDT WED AUG 15 2012
AS A COLD FRONT MOVES THROUGH LAKE SUPERIOR...EXPECT A SHARP WIND
SHIFT TO THE W LATE TONIGHT AND THU FOLLOWING THIS FRONTAL PASSAGE.
THE ARRIVAL OF MUCH COOLER AIR IN THE WAKE OF THE FRONT OVER THE
WARM WATERS OF LAKE SUPERIOR WILL ALSO RESULT IN ENHANCED MIXING
OVER THE LAKE WITH W-NW WINDS UP TO 30 KTS AND POSSIBLE GALES TO 35
KNOTS OVER THE N CNTRL PORTION OF THE LAKE...FROM LATE THURSDAY
AFTERNOON THROUGH THURSDAY NIGHT WHERE A GALE WATCH WAS POSTED.
SINCE MODELS HAVE TRENDED STRONGER WITH THE LOW LEVEL WIND FIELDS
THERE IS ALSO THE POTENTIAL FOR THE WATCH TO BE EXPANDED AND OR A
WARNING ISSUED FOR A LARGER AREA OF THE LAKE. EXPECT THE STRONGER NW
WINDS TO SLOWLY SUBSIDE ON FRI THRU THE WEEKEND AS THE PRES GRADIENT
WEAKENS WITH BROAD HIGH PRESSURE SETTLING OVER THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM THURSDAY AFTERNOON THROUGH LATE THURSDAY NIGHT
FOR LSZ264-266.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...JLB
LONG TERM...KEC
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
724 PM EDT WED AUG 15 2012
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 425 PM EDT WED AUG 15 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A POSITIVE TILT MID/UPPER
LEVEL TROUGH FROM NRN MANITOBA INTO ERN MT WITH A DOWNSTREAM RIDGE
FROM THE WRN GREAT LAKES INTO NRN ONTARIO. AT THE SFC...A COLD FRONT
EXTENDED THROUGH THE ERN DAKOTAS FROM LOW PRES OVER SE MANITOBA.
LIGHT SHOWERS OVER WRN WI THAT HAD DEVELOPED WITH WAA/305-310K
ISENTROPIC LIFT HAD DISSIPATED AS THEY MOVED INTO DRIER AIR TO THE
EAST...LEAVING MAINLY JUST BKN MID CLOUDS UPSTREAM OVER NW WI. SCT
SHRA/TSRA HAD ALSO DEVELOPED AHEAD OF THE FRONT OVER NW MN.
TONIGHT AND THURSDAY...EVEN THOUGH THE NAM/RUC SEEM OVERDONE WITH
THE AMOUNT OF WAA PCPN INTO THE AREA LATE THIS AFTERNOON AND
EVENING...COMPARED TO CURRENT TRENDS...CANNOT RULE OUT SOME LIGHT
SHOWERS DEVELOPING OVER THE WEST THIS EVENING WHERE SLIGHT CHANCE
POPS WERE RETAINED. OTHERWISE...MORE WIDESPREAD PCPN SHOULD MOVE
INTO THE CWA...MAINLY AFT 06Z AS THE MODELS HAVE TRENDED TOWARD A
SLOWER ARRIVAL OF GREATEST SHRA/TSRA CHANCES. FAVORABLE DYNAMICS
WITH 700-300 MB QVECTOR CONV AHEAD OF THE MID LEVEL TROUGH AND LOW
LEVEL CONV WITH THE FRONT SHOULD SUPPORT CATEGORICAL POPS LATE
TONIGHT INTO THURSDAY MORNING. THE SHRA/TSRA SHOULD EXIT CNTRL UPPER
MI IN THE MORNING AND THE ERN CWA DURING THE EARLY AFTERNOON. THERE
IS LESS CONFIDENCE WITH POTENTIAL FOR HIGHER PCPN AMOUNTS OR SEVERE
WEATHER AS THE GREATER MOISTURE INFLOW AND INSTABILITY WILL REMAIN
FARTHER SOUTH OVER WI.
STRENGTHENING WIND FIELDS WITH 0-6KM SHEAR VALUES INTO THE 30-35 KT
ARE EXPECTED AS THE SHRA/TSRA ARRIVES BUT MAY LAG THE BEST LOW LEVEL
FORCING. NEVERTHELESS THERE IS LIMITED SVR POTENTIAL WITH MUCAPE
VALUES FCST INTO THE 500-1000 J/KG RANGE. IF STRONGER LINEAR
CONVECTIVE AREAS SURVIVE AS THEY MOVE OUT OF MN AND NW WI...SOME
DAMAGING WIND GUSTS MAY BE POSSIBLE AS THE MAIN HAZARD...PER SPC.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 425 PM EDT WED AUG 15 2012
TEMPERATURES THROUGH THE EXTENDED WILL REMAIN BELOW NORMAL WITH A
WARMING TREND BEGINNING LATE IN THE PERIOD.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...THE UPPER LEVEL AND SURFACE
LOW WILL BECOME VERTICALLY STACKED THURSDAY NIGHT INTO FRIDAY AS THE
LOW SHIFTS FROM CENTRAL ONTARIO NORTH AND EASTWARD TO JAMES BAY. AS
THIS HAPPENS THE UPPER LEVEL TROUGH AXIS WILL SWING ACROSS UPPER
MICHIGAN. THE COOLER AIR ALOFT ASSOCIATED WITH THIS TROUGH WILL HELP
TO CREATE CONDITIONS FAVORABLE FOR LAKE EFFECT RAIN SHOWERS ACROSS
MAINLY CENTRAL PORTIONS OF UPPER MICHIGAN. H850 TEMPS ARE PROGGED TO
BE AROUND 4 TO 6C WITH SURFACE TEMPS AROUND 18 TO 19C ACROSS THE
AREA...WHICH SHOULD CREATE A LARGE ENOUGH TEMPERATURE DIFFERENCE TO
CAUSE THE LAKE EFFECT RAIN SHOWERS TO FORM. ALONG WITH THE RAIN
SHOWERS...HIGH WINDS ARE ALSO POSSIBLE OVER THE LAKE THURSDAY
AFTERNOON INTO THURSDAY NIGHT AS 30 TO 35 KNOT WINDS...AS SHOWN BY
THE EC/GFS...MIX DOWN TO THE LAKE SURFACE. AS THE UPPER LEVEL LOW
SHIFTS NORTHEASTWARD AND THE UPPER LEVEL TROUGH AXIS SHIFTS PAST THE
UPPER PENINSULA FRIDAY NIGHT...H850 TEMPS ARE EXPECTED TO
WARM...EFFECTIVELY REDUCING THE LAKE EFFECT RAIN SHOWER CHANCES. A
COOL NIGHT IS IN STORE FOR FRIDAY NIGHT AS WINDS BECOME LIGHT AND
SKIES BECOME MOSTLY CLEAR. TEMPERATURES AREA EXPECTED TO BE IN THE
LOW TO MID 40S ACROSS MAINLY INLAND AREAS...WITH A FEW OF THE USUAL
COOL SPOTS POTENTIALLY FALLING INTO THE UPPER 30S.
SATURDAY THROUGH MONDAY...A WEAK COLD FRONT WILL PUSH SOUTHWARD INTO
THE U.P. SATURDAY AFTERNOON THROUGH SUNDAY. A 500MB SHORTWAVE IS
ALSO PROGGED TO MOVE THROUGH THE AREA SATURDAY NIGHT THROUGH
MONDAY...AS IT ROTATES AROUND THE LOW CENTERED OVER JAMES BAY. THIS
SHOULD PROVIDE ENOUGH FORCING FOR A FEW SHOWERS TO DEVELOP THROUGH
THIS TIME PERIOD...HOWEVER...MOISTURE SHOULD BE FAIRLY LIMITED AS A
SURFACE HIGH PRESSURE SYSTEM WILL REMAIN CENTERED TO THE SOUTH
SOUTHWEST OF THE AREA KEEPING DRIER AIR ADVECTING INTO THE AREA FROM
THE WEST.
MONDAY NIGHT THROUGH WEDNESDAY...AS THE UPPER LEVEL LOW BEGINS TO
DRIFT SLOWLY EASTWARD...A RIDGE BUILDING OVER MUCH OF THE PLAINS
STATES WILL BEGIN TO WEAKEN AS IT TRIES TO BUILD EASTWARD INTO THE
UPPER GREAT LAKES REGION. THIS SHOULD ALLOW TEMPERATURES TO INCREASE
TO NEAR NORMAL LEVELS BY TUESDAY AND INTO THE DAY WEDNESDAY. TUESDAY
NIGHT INTO WEDNESDAY BOTH THE GFS/EC HAVE A SHORTWAVE ROTATING
AROUND THE RIDGE ALONG WITH A SURFACE LOW JUST TO THE WEST OF THE
REGION...BRINGING THE NEXT CHANCE OF SHOWERS TO THE AREA.
HOWEVER...WITH CONSIDERABLE DIFFERENCES IN SURFACE LOW PLACEMENT AND
STRENGTH HAVE DECIDED TO STICK TO A CONSENSUS OF THE MODELS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 722 PM EDT WED AUG 15 2012
EXPECT VFR CONDITIONS THRU THIS EVNG AT ALL 3 TAF SITES WITH SSE
TRAJECTORIES MAINTAINING SOME DRY LLVL AIR. THE APRCH OF A COLD FNT
LATER WL BRING THE THREAT OF TS TO AT LEAST IWD BY 06Z. BUT THESE
STORMS ARE LIKELY TO WEAKEN BEFORE REACHING CMX AND ESPECIALLY SAW
TOWARD 09Z. FOLLOWING THE FROPA...A WSHFT TO THE WNW WL ADVECT
COOLER AND MOISTER LLVL AIR INTO THE AREA...RESULTING IN LO CLDS/
MVFR CONDITIONS AND STRENGTHENING WINDS. THE BEST CHC FOR IFR
CONDITIONS AND STRONGER WINDS WL BE AT THE MORE EXPOSED CMX SITE
WITH A MORE PRONOUNCED UPSLOPE WIND COMPONENT. EXPECT THESE LO CIGS
TO SLOWLY LIFT DURING THE DAY...BUT MVFR CIGS MAY LINGER ALL DAY AT
CMX...WHERE WIND GUSTS MAY APRCH 35 KTS WITH THE APRCH OF AXIS OF
COOLEST AIR/MORE INSTABILITY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 425 PM EDT WED AUG 15 2012
AS A COLD FRONT MOVES THROUGH LAKE SUPERIOR...EXPECT A SHARP WIND
SHIFT TO THE W LATE TONIGHT AND THU FOLLOWING THIS FRONTAL PASSAGE.
THE ARRIVAL OF MUCH COOLER AIR IN THE WAKE OF THE FRONT OVER THE
WARM WATERS OF LAKE SUPERIOR WILL ALSO RESULT IN ENHANCED MIXING
OVER THE LAKE WITH W-NW WINDS UP TO 30 KTS AND POSSIBLE GALES TO 35
KNOTS OVER THE N CNTRL PORTION OF THE LAKE...FROM LATE THURSDAY
AFTERNOON THROUGH THURSDAY NIGHT WHERE A GALE WATCH WAS POSTED.
SINCE MODELS HAVE TRENDED STRONGER WITH THE LOW LEVEL WIND FIELDS
THERE IS ALSO THE POTENTIAL FOR THE WATCH TO BE EXPANDED AND OR A
WARNING ISSUED FOR A LARGER AREA OF THE LAKE. EXPECT THE STRONGER NW
WINDS TO SLOWLY SUBSIDE ON FRI THRU THE WEEKEND AS THE PRES GRADIENT
WEAKENS WITH BROAD HIGH PRESSURE SETTLING OVER THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM THURSDAY AFTERNOON THROUGH LATE THURSDAY NIGHT
FOR LSZ264-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KEC
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION...CORRECTION
NWS GRAND RAPIDS MI
346 PM EDT TUE AUG 14 2012
.SYNOPSIS...
ISSUED AT 312 PM EDT TUE AUG 14 2012
AN AREA OF HIGH PRESSURE WILL PASS SOUTH OF MICHIGAN TONIGHT INTO
WEDNESDAY. THIS SHOULD PROVIDE MOSTLY PARTLY CLOUDY SKIES AND LIGHT
WINDS OVERNIGHT. AS THE HIGH MOVES EAST OF THE AREA WEDNESDAY
SOUTHERLY WINDS WILL BRING HIGHS INTO THE LOWER 80S INLAND OF LAKE
MICHIGAN BY MID AFTERNOON. A COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY WITH SHOWERS AND THUNDERSTORMS. BEHIND THE FRONT EXPECT
COOLER WEATHER INTO THE WEEKEND WITH ONLY A SLIGHT CHANCE OF
SHOWERS EACH DAY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 312 PM EDT TUE AUG 14 2012
THE MAIN ISSUE WITH THIS FORECAST IS THE THREAT FOR STRONG
THUNDERSTORMS ON THURSDAY WITH THE COLD FRONT. THERE IS ALSO A
LESSER ISSUE WITH THE SHOWERS ASSOCIATED WITH THE WEAK FRONT
MOVING THROUGH THE AREA THIS EVENING.
AS FOR THE EVENING SHOWERS... THE RAP MODEL SOUNDING SHOW THE
EQUILIBRIUM LEVEL NEAR 36,000 FT AGL FOR LATE AFTERNOON AND
EVENING WITH CAPES NEAR 1000 J/KG NORTH AND EAST OF GRR. HOWEVER
THOSE SAME SOUNDING SHOW DEW POINT DEPRESSIONS OF OVER 25C BETWEEN
700 AND 400 MB. AS IT TURNS OUT THE SHOWERS ARE ACTUALLY TOPPING
OUT BELOW 20000 FT AGL. THESE SHOWERS ARE ON A WEAK SHORTWAVE AND
THE SURFACE COLD FRONT MOVING ACROSS CENTRAL LOWER MICHIGAN. ALL
OF THIS SHOULD BE EAST OF THE CWA BY SUNSET.
AS FOR THE CONVECTION ON THE COLD FRONT THURSDAY... SEEMS THE
MODELS ARE SIMILAR NOW IN THE TIMING OF THE FRONT... DURING THE
MID TO LATE AFTERNOON. THAT WOULD SUPPORT THE IDEA OF STRONGER
STORMS AS WOULD THE FORECAST OF A STRENGTHENING LOW LEVEL JET HOWEVER
THE CORE OF THE SPEED MAX IS NORTH AND EAST OF GRR THURSDAY
AFTERNOON WHICH MEANS SPEED DIVERGENCE OVER MOST OF THE CWA DURING
THE PRIME THUNDERSTORM DEVELOPMENT TIME. ALSO NOT SO GOOD IS THE
NAM IS SHOWING UPPER CONVERGENCE OVER SURFACE CONVERGENCE AT 18Z
THURSDAY. RATHER NOT CONDUCIVE FOR STRONG STORMS EITHER. THAT IS
BECAUSE GRR IS UNDER THE RIGHT EXIT REGION OF THE UPPER JET. BY
EVENING AS THE CONVECTION REACHES EASTER LOWER MICHIGAN THE
DYNAMICS IMPROVE. BESIDE ALL OF THAT THERE WILL BE CONSIDERABLE
CLOUDS OVER THE CWA WITH THE FRONT WHICH WILL HOLD DOWN THE
SURFACE TEMPS TOO. SO MY SPIN IS WE WILL SEE A LINE OF STRENGTHENING
STORMS OVER OUR EASTERN CWA DURING THE AFTERNOON.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 345 PM EDT TUE AUG 14 2012
MAIN FORECAST CHALLENGE IS RAIN CHANCES. MAIN CHANGE WAS TO FEATURE
AT LEAST SLIGHT CHANCE POPS FOR ALMOST THE ENTIRE PERIOD.
MODELS FEATURE STRONGLY CYCLONIC FLOW ALOFT ACROSS THE GREAT LAKES
DURING THIS PERIOD. THIS IS ASSOCIATED WITH A PERSISTENT UPPER LOW
CENTERED OVER HUDSON BAY. SEVERAL REINFORCING POT VORT MAXES
ROTATING AROUND THE LOW SHOULD HELP TO ANCHOR IT AND FORCE MULTIPLE
EPISODES OF RAIN SHOWERS OVER OUR AREA. THE SPECIFICS ON
PRECIPITATION FREQUENCY...TIMING AND AMOUNTS ALL REMAIN VERY
UNCERTAIN. HOWEVER...THE HIGHLY UNSETTLED OVERALL PATTERN JUSTIFIES
AT LEAST SLIGHT CHANCE POPS THROUGHOUT. TEMPERATURES WILL BE
SIGNIFICANTLY COOLER THAN NORMAL WITH SOME DAYS POSSIBLY STRUGGLING
TO GET INTO THE 60S DEPENDING ON THE TIMING AND INTENSITY OF
PRECIPITATION THAT OCCURS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 102 PM EDT TUE AUG 14 2012
JUST SOME SCATTERED CU THIS AFTERNOON AND LIGHT WINDS EXPECTED.
LATER TONIGHT...WE COULD SEE SOME REDUCED VISBYS DEVELOP
PARTICULARLY ACROSS SOUTH CENTRAL AND SE LOWER MICHIGAN AS SKIES
SHOULD REMAIN MOSTLY CLEAR THERE. LOOKS LIKE 3-5 SM VISBYS POSSIBLE
SO WENT WITH 4SM AS AN AVERAGE. MID LEVEL CLOUDS AOA 10K FT SHOULD
MOVE IN TOWARD MID MORNING AND LIKELY MITIGATE FG DEVELOPMENT
ESPECIALLY ACROSS SW LOWER MICHIGAN. WILL CONTINUE TO MONITOR.
&&
.MARINE...
ISSUED AT 312 PM EDT TUE AUG 14 2012
WINDS WILL BE CONDUCIVE TO HIGHER WAVES THURSDAY AHEAD OF THE
FRONT AND EVEN MORE SO BEHIND THE COLD FRONT THURSDAY NIGHT. WE
WILL LIKELY HAVE TO ISSUE A SMALL CRAFT ADVIOSRY AND BEACH HAZARD
STATEMENTS.
&&
.HYDROLOGY...
ISSUED AT 312 PM EDT TUE AUG 14 2012
RIVERS ARE RUNNING WELL BELOW ADVISORY LEVELS AND RAINFALL
THURSDAY WILL NOT BE ENOUGH TO CHANGE THAT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...TJT
AVIATION...HOVING
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
342 PM EDT TUE AUG 14 2012
.SYNOPSIS...
ISSUED AT 312 PM EDT TUE AUG 14 2012
AN AREA OF HIGH PRESSURE WILL PASS SOUTH OF MICHIGAN TONIGHT INTO
WEDNESDAY. THIS SHOULD PROVIDE MOSTLY PARTLY CLOUDY SKIES AND HIGH
WINDS OVERNIGHT. AS THE HIGH MOVES EAST OF THE AREA WEDNESDAY
SOUTHERLY WINDS WILL BRING HIGHS INTO THE LOWER 80S INLAND OF LAKE
MICHIGAN BY MID AFTERNOON. A COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY WITH SHOWERS AND THUNDERSTORMS. BEHIND THE FRONT EXPECT
COOLER WEATHER INTO THE WEEKEND WITH ONLY A SLIGHT CHANCE OF
SHOWERS EACH DAY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 312 PM EDT TUE AUG 14 2012
THE MAIN ISSUE WITH THIS FORECAST IS THE THREAT FOR STRONG
THUNDERSTORMS ON THURSDAY WITH THE COLD FRONT. THERE IS ALSO A
LESSER ISSUE WITH THE SHOWERS ASSOCIATED WITH THE WEAK FRONT
MOVING THROUGH THE AREA THIS EVENING.
AS FOR THE EVENING SHOWERS... THE RAP MODEL SOUNDING SHOW THE
EQUILIBRIUM LEVEL NEAR 36,000 FT AGL FOR LATE AFTERNOON AND
EVENING WITH CAPES NEAR 1000 J/KG NORTH AND EAST OF GRR. HOWEVER
THOSE SAME SOUNDING SHOW DEW POINT DEPRESSIONS OF OVER 25C BETWEEN
700 AND 400 MB. AS IT TURNS OUT THE SHOWERS ARE ACTUALLY TOPPING
OUT BELOW 20000 FT AGL. THESE SHOWERS ARE ON A WEAK SHORTWAVE AND
THE SURFACE COLD FRONT MOVING ACROSS CENTRAL LOWER MICHIGAN. ALL
OF THIS SHOULD BE EAST OF THE CWA BY SUNSET.
AS FOR THE CONVECTION ON THE COLD FRONT THURSDAY... SEEMS THE
MODELS ARE SIMILAR NOW IN THE TIMING OF THE FRONT... DURING THE
MID TO LATE AFTERNOON. THAT WOULD SUPPORT THE IDEA OF STRONGER
STORMS AS WOULD THE FORECAST OF A STRENGTHENING LOW LEVEL JET HOWEVER
THE CORE OF THE SPEED MAX IS NORTH AND EAST OF GRR THURSDAY
AFTERNOON WHICH MEANS SPEED DIVERGENCE OVER MOST OF THE CWA DURING
THE PRIME THUNDERSTORM DEVELOPMENT TIME. ALSO NOT SO GOOD IS THE
NAM IS SHOWING UPPER CONVERGENCE OVER SURFACE CONVERGENCE AT 18Z
THURSDAY. RATHER NOT CONDUCIVE FOR STRONG STORMS EITHER. THAT IS
BECAUSE GRR IS UNDER THE RIGHT EXIT REGION OF THE UPPER JET. BY
EVENING AS THE CONVECTION REACHES EASTER LOWER MICHIGAN THE
DYNAMICS IMPROVE. BESIDE ALL OF THAT THERE WILL BE CONSIDERABLE
CLOUDS OVER THE CWA WITH THE FRONT WHICH WILL HOLD DOWN THE
SURFACE TEMPS TOO. SO MY SPIN IS WE WILL SEE A LINE OF STRENGTHENING
STORMS OVER OUR EASTERN CWA DURING THE AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 406 AM EDT TUE AUG 14 2012
A COLD FRONT WILL PUSH SOUTH OF THE AREA THURSDAY NIGHT...USHERING
IN A COOL FALL LIKE AIR MASS FOR THE WEEKEND. MAIN POINTS OF
CONTENTION IN THE LONG TERM ARE PRECIP CHANCES AND CHANCES FOR
STRONGER STORMS THURSDAY NIGHT...AND UPPER LOW SHOWER POTENTIAL OVER
THE WEEKEND.
COLD FRONT SHOULD BISECT THE FORECAST AREA FROM NORTHEAST TO
SOUTHWEST THURSDAY EVENING WITH SHOWERS AND THUNDERSTORMS ACROSS THE
CWA. BEST CHANCES WILL LIKELY BE ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA. PRECIPITATION WILL LIKELY MOVE SOUTH OF THE AREA BY
FRIDAY MORNING. AS FOR THREAT OF STRONG STORMS...FEEL BETTER
INSTABILITY WILL BE JUST SOUTH AND EAST OF THE FORECAST AREA
THURSDAY NIGHT.
ENVISION DIURNALLY DRIVEN SHOWERS OVER THE WEEKEND WITH AN UPPER LOW
OVERHEAD. LOW LEVEL MOISTURE OFF THE GREAT LAKES WILL LIKELY ADD TO
THE INSTABILITY THAT WILL BE IN PLACE DUE TO THE COLD MID LEVELS.
GFS AND ECMWF STILL AT ODDS OVER A SHORTWAVE AND SURFACE TROUGH THAT
THE GFS SWINGS THROUGH THE GREAT LAKES SUNDAY NIGHT AND MONDAY. HAVE
20 POPS IN THE FORECAST AT THIS POINT UNTIL BETTER AGREEMENT OCCURS.
BOTTOM LINE CONTINUES TO BE A FALL LIKE FEEL FOR LATE IN THE WEEK
AND THE WEEKEND...AS HIGHS AROUND 70 FRI/SAT ONLY WARM TO THE LOW TO
MID 70S SUN/MON.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 102 PM EDT TUE AUG 14 2012
JUST SOME SCATTERED CU THIS AFTERNOON AND LIGHT WINDS EXPECTED.
LATER TONIGHT...WE COULD SEE SOME REDUCED VISBYS DEVELOP
PARTICULARLY ACROSS SOUTH CENTRAL AND SE LOWER MICHIGAN AS SKIES
SHOULD REMAIN MOSTLY CLEAR THERE. LOOKS LIKE 3-5 SM VISBYS POSSIBLE
SO WENT WITH 4SM AS AN AVERAGE. MID LEVEL CLOUDS AOA 10K FT SHOULD
MOVE IN TOWARD MID MORNING AND LIKELY MITIGATE FG DEVELOPMENT
ESPECIALLY ACROSS SW LOWER MICHIGAN. WILL CONTINUE TO MONITOR.
&&
.MARINE...
ISSUED AT 312 PM EDT TUE AUG 14 2012
WINDS WILL BE CONDUCIVE TO HIGHER WAVES THURSDAY AHEAD OF THE
FRONT AND EVEN MORE SO BEHIND THE COLD FRONT THURSDAY NIGHT. WE
WILL LIKELY HAVE TO ISSUE A SMALL CRAFT ADVIOSRY AND BEACH HAZARD STATEMENTS.
&&
.HYDROLOGY...
ISSUED AT 312 PM EDT TUE AUG 14 2012
RIVERS ARE RUNNING WELL BELOW ADVISORY LEVELS AND RAINFALL
THURSDAY WILL NOT BE ENOUGH TO CHANGE THAT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...DUKE
AVIATION...HOVING
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
102 PM EDT TUE AUG 14 2012
.SYNOPSIS...
ISSUED AT 406 AM EDT TUE AUG 14 2012
AFTER A MORNING OF AREAS OF DENSE FOG AND SCATTERED RAIN
SHOWERS...MUCH OF THE AREA WILL SEE CLEARING SKIES THIS AFTERNOON.
MUCH OF THE REGION WILL SEE DRY CONDITIONS TONIGHT THROUGH
WEDNESDAY NIGHT AS HIGH PRESSURE MOVES THROUGH. THE CHANCE OF RAIN
WILL COME THURSDAY AS A STRONG COLD FRONT PUSHES THROUGH. MUCH
COOLER WEATHER IS EXPECTED BY THE END OF THE WEEK.
&&
.UPDATE...
ISSUED AT 1058 AM EDT TUE AUG 14 2012
I EXPUNGED THE FOG FROM OUR GRIDS AND UPDATED OUR ZONE FORECAST TO
DROP ANY REFERENCE TO THE FOG. CURIOUS HOW THE LOW CLOUDS ARE
MIXING OUT MORE QUICKLY ALONG INTERSTATE 96 THEN ELSEWHERE... SO I
TRENDED THE CLOUD GRID THAT WAY. THAT IS I HAVE MORE CLOUDS NORTH
AND SOUTH OF INTERSTATE 96 INTO EARLY AFTERNOON TO ALLOW FOR THE
CLOUDS THAT ARE THERE TO MIX OUT.
A WEAK SHORTWAVE... AS SEEN ON THE RAP DATA AND ALSO SEEN ON THE
WATER VAPOR LOOP... MAY TOUCH OFF AN ISOLATED THUNDERSTORM OVER
OUR NE CWA THIS AFTERNOON. THE SOUNDING DO SHOW CAPES TO NEAR 1000
J/KG AND THE TQ INDEX RISES TO NEAR 25C WHICH IS WELL ABOVE THE
15C THRESHOLD FOR THUNDERSTORM. PROBLEM IS THERE IS VERY LITTLE
MOISTURE IN THE SOUNDINGS BETWEEN 10,000 AND 20,000 FT SO ANY CU
TOWERS THAT WOULD DEVELOP WILL HAVE TO STRUGGLE WITH THE DRY AIR
ENTRAINMENT. EVEN SO I PUT 20 POPS THIS AFTERNOON FOR THAT AREA.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 406 AM EDT TUE AUG 14 2012
WILL GO WITH A DENSE FOG ADVISORY FOR NW AREAS OF THE CWA. THIS
AREA HAS SEEN THE MID LEVEL CLOUDS PEEL AWAY AND FOG IS DEVELOPING
UNDER THE CLEAR SKIES. OTHERWISE THE FEW LEFTOVER SHOWER IN THE
EASTERN CWA SHOULD BE CLEARING OUT THE OF CWA BY LATE MORNING.
EXPECT A FAIRLY RAPID CLEARING BEHIND THE SHOWERS INTO THE AFTERNOON.
QUIET WEATHER EXPECTED TONIGHT THROUGH WEDNESDAY NIGHT. TEMPS WILL
REBOUND TO 80 TO 85 FOR WEDNESDAY AS WE BEGIN TO SEE RETURN FLOW
AROUND A SURFACE HIGH.
CURRENT TIMING OF THE COLD FRONT ON THURSDAY MAY DIMINISH A SEVERE
THREAT. MODELS SUGGEST IT WILL PASS THROUGH EARLY AFTERNOON WITH
PLENTY OF CLOUDS AND SHOWERS AHEAD OF IT. THIS MAKES THE
OPPORTUNITY TO BECOME UNSTABLE QUESTIONABLE. EVEN SO...WE SHOULD
SEE A GOOD CHANCE OF SHOWERS AND A FEW STORMS...SO EXPANDED THE
LIKELY POPS OVER ALL OF THE CWA.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 406 AM EDT TUE AUG 14 2012
A COLD FRONT WILL PUSH SOUTH OF THE AREA THURSDAY NIGHT...USHERING
IN A COOL FALL LIKE AIR MASS FOR THE WEEKEND. MAIN POINTS OF
CONTENTION IN THE LONG TERM ARE PRECIP CHANCES AND CHANCES FOR
STRONGER STORMS THURSDAY NIGHT...AND UPPER LOW SHOWER POTENTIAL OVER
THE WEEKEND.
COLD FRONT SHOULD BISECT THE FORECAST AREA FROM NORTHEAST TO
SOUTHWEST THURSDAY EVENING WITH SHOWERS AND THUNDERSTORMS ACROSS THE
CWA. BEST CHANCES WILL LIKELY BE ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA. PRECIPITATION WILL LIKELY MOVE SOUTH OF THE AREA BY
FRIDAY MORNING. AS FOR THREAT OF STRONG STORMS...FEEL BETTER
INSTABILITY WILL BE JUST SOUTH AND EAST OF THE FORECAST AREA
THURSDAY NIGHT.
ENVISION DIURNALLY DRIVEN SHOWERS OVER THE WEEKEND WITH AN UPPER LOW
OVERHEAD. LOW LEVEL MOISTURE OFF THE GREAT LAKES WILL LIKELY ADD TO
THE INSTABILITY THAT WILL BE IN PLACE DUE TO THE COLD MID LEVELS.
GFS AND ECMWF STILL AT ODDS OVER A SHORTWAVE AND SURFACE TROUGH THAT
THE GFS SWINGS THROUGH THE GREAT LAKES SUNDAY NIGHT AND MONDAY. HAVE
20 POPS IN THE FORECAST AT THIS POINT UNTIL BETTER AGREEMENT OCCURS.
BOTTOM LINE CONTINUES TO BE A FALL LIKE FEEL FOR LATE IN THE WEEK
AND THE WEEKEND...AS HIGHS AROUND 70 FRI/SAT ONLY WARM TO THE LOW TO
MID 70S SUN/MON.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 102 PM EDT TUE AUG 14 2012
JUST SOME SCATTERED CU THIS AFTERNOON AND LIGHT WINDS EXPECTED.
LATER TONIGHT...WE COULD SEE SOME REDUCED VISBYS DEVELOP
PARTICULARLY ACROSS SOUTH CENTRAL AND SE LOWER MICHIGAN AS SKIES
SHOULD REMAIN MOSTLY CLEAR THERE. LOOKS LIKE 3-5 SM VISBYS POSSIBLE
SO WENT WITH 4SM AS AN AVERAGE. MID LEVEL CLOUDS AOA 10K FT SHOULD
MOVE IN TOWARD MID MORNING AND LIKELY MITIGATE FG DEVELOPMENT
ESPECIALLY ACROSS SW LOWER MICHIGAN. WILL CONTINUE TO MONITOR.
&&
.MARINE...
ISSUED AT 406 AM EDT TUE AUG 14 2012
LIGHT WINDS AND LOW WAVES WILL BE THE SEEN THROUGH WEDNESDAY.
HOWEVER SOUTHERN WINDS WILL BE RAMPING UP WEDNESDAY NIGHT AND
THURSDAY...AHEAD AND AS THE FRONT COMES THROUGH. WE MAY APPROACH
SCA CONDITIONS LATE WEDNESDAY NIGHT/EARLY THURSDAY...BUT THERE
WILL BE EVEN STRONG WINDS IN THE CAA BEHIND THE FRONT BY THE END
OF THE WEEK.
&&
.HYDROLOGY...
ISSUED AT 406 AM EDT TUE AUG 14 2012
NEXT DECENT CHANCE OF RAIN WILL COME THURSDAY/THURSDAY NIGHT WITH
A STRONG COLD FRONT. MANY AREAS SHOULD SEE AROUND A HALF INCH OF
RAIN...WITH LOCALIZED HIGHER AMOUNTS. THIS SHOULD NOT CAUSE ANY
WIDESPREAD HYDRO CONCERNS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...DUKE
AVIATION...HOVING
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1057 AM EDT TUE AUG 14 2012
.SYNOPSIS...
ISSUED AT 406 AM EDT TUE AUG 14 2012
AFTER A MORNING OF AREAS OF DENSE FOG AND SCATTERED RAIN
SHOWERS...MUCH OF THE AREA WILL SEE CLEARING SKIES THIS AFTERNOON.
MUCH OF THE REGION WILL SEE DRY CONDITIONS TONIGHT THROUGH
WEDNESDAY NIGHT AS HIGH PRESSURE MOVES THROUGH. THE CHANCE OF RAIN
WILL COME THURSDAY AS A STRONG COLD FRONT PUSHES THROUGH. MUCH
COOLER WEATHER IS EXPECTED BY THE END OF THE WEEK.
&&
.UPDATE...
ISSUED AT 1058 AM EDT TUE AUG 14 2012
I EXPUNGED THE FOG FROM OUR GRIDS AND UPDATED OUR ZONE FORECAST TO
DROP ANY REFERENCE TO THE FOG. CURIOUS HOW THE LOW CLOUDS ARE
MIXING OUT MORE QUICKLY ALONG INTERSTATE 96 THEN ELSEWHERE... SO I
TRENDED THE CLOUD GRID THAT WAY. THAT IS I HAVE MORE CLOUDS NORTH
AND SOUTH OF INTERSTATE 96 INTO EARLY AFTERNOON TO ALLOW FOR THE
CLOUDS THAT ARE THERE TO MIX OUT.
A WEAK SHORTWAVE... AS SEEN ON THE RAP DATA AND ALSO SEEN ON THE
WATER VAPOR LOOP... MAY TOUCH OFF AN ISOLATED THUNDERSTORM OVER
OUR NE CWA THIS AFTERNOON. THE SOUNDING DO SHOW CAPES TO NEAR 1000
J/KG AND THE TQ INDEX RISES TO NEAR 25C WHICH IS WELL ABOVE THE
15C THRESHOLD FOR THUNDERSTORM. PROBLEM IS THERE IS VERY LITTLE
MOISTURE IN THE SOUNDINGS BETWEEN 10,000 AND 20,000 FT SO ANY CU
TOWERS THAT WOULD DEVELOP WILL HAVE TO STRUGGLE WITH THE DRY AIR
ENTRAINMENT. EVEN SO I PUT 20 POPS THIS AFTERNOON FOR THAT AREA.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 406 AM EDT TUE AUG 14 2012
WILL GO WITH A DENSE FOG ADVISORY FOR NW AREAS OF THE CWA. THIS
AREA HAS SEEN THE MID LEVEL CLOUDS PEEL AWAY AND FOG IS DEVELOPING
UNDER THE CLEAR SKIES. OTHERWISE THE FEW LEFTOVER SHOWER IN THE
EASTERN CWA SHOULD BE CLEARING OUT THE OF CWA BY LATE MORNING.
EXPECT A FAIRLY RAPID CLEARING BEHIND THE SHOWERS INTO THE AFTERNOON.
QUIET WEATHER EXPECTED TONIGHT THROUGH WEDNESDAY NIGHT. TEMPS WILL
REBOUND TO 80 TO 85 FOR WEDNESDAY AS WE BEGIN TO SEE RETURN FLOW
AROUND A SURFACE HIGH.
CURRENT TIMING OF THE COLD FRONT ON THURSDAY MAY DIMINISH A SEVERE
THREAT. MODELS SUGGEST IT WILL PASS THROUGH EARLY AFTERNOON WITH
PLENTY OF CLOUDS AND SHOWERS AHEAD OF IT. THIS MAKES THE
OPPORTUNITY TO BECOME UNSTABLE QUESTIONABLE. EVEN SO...WE SHOULD
SEE A GOOD CHANCE OF SHOWERS AND A FEW STORMS...SO EXPANDED THE
LIKELY POPS OVER ALL OF THE CWA.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 406 AM EDT TUE AUG 14 2012
A COLD FRONT WILL PUSH SOUTH OF THE AREA THURSDAY NIGHT...USHERING
IN A COOL FALL LIKE AIR MASS FOR THE WEEKEND. MAIN POINTS OF
CONTENTION IN THE LONG TERM ARE PRECIP CHANCES AND CHANCES FOR
STRONGER STORMS THURSDAY NIGHT...AND UPPER LOW SHOWER POTENTIAL OVER
THE WEEKEND.
COLD FRONT SHOULD BISECT THE FORECAST AREA FROM NORTHEAST TO
SOUTHWEST THURSDAY EVENING WITH SHOWERS AND THUNDERSTORMS ACROSS THE
CWA. BEST CHANCES WILL LIKELY BE ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA. PRECIPITATION WILL LIKELY MOVE SOUTH OF THE AREA BY
FRIDAY MORNING. AS FOR THREAT OF STRONG STORMS...FEEL BETTER
INSTABILITY WILL BE JUST SOUTH AND EAST OF THE FORECAST AREA
THURSDAY NIGHT.
ENVISION DIURNALLY DRIVEN SHOWERS OVER THE WEEKEND WITH AN UPPER LOW
OVERHEAD. LOW LEVEL MOISTURE OFF THE GREAT LAKES WILL LIKELY ADD TO
THE INSTABILITY THAT WILL BE IN PLACE DUE TO THE COLD MID LEVELS.
GFS AND ECMWF STILL AT ODDS OVER A SHORTWAVE AND SURFACE TROUGH THAT
THE GFS SWINGS THROUGH THE GREAT LAKES SUNDAY NIGHT AND MONDAY. HAVE
20 POPS IN THE FORECAST AT THIS POINT UNTIL BETTER AGREEMENT OCCURS.
BOTTOM LINE CONTINUES TO BE A FALL LIKE FEEL FOR LATE IN THE WEEK
AND THE WEEKEND...AS HIGHS AROUND 70 FRI/SAT ONLY WARM TO THE LOW TO
MID 70S SUN/MON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 741 AM EDT TUE AUG 14 2012
DEEPER MOISTURE IS MOVING EAST OF THE AREA THIS MORNING ALLOWING
FOG TO FORM IN ITS WAKE. LIFR CONDITIONS HAVE DEVELOPED ACROSS
MUCH OF THE AREA WHERE THE DEEPER MOISTURE HAS EXITED TO THE EAST.
THE LIFR CONDITIONS SHOULD LIFT RATHER QUICKLY THIS MORNING THOUGH
AS THE MOISTURE IS QUITE SHALLOW. BY 15Z...MOST AREAS SHOULD BE
VFR.
SCATTERED TO OCCASIONALLY BROKEN CUMULUS CLOUDS CAN BE EXPECTED
THROUGH THE BULK OF THE DAY...DISSIPATING WITH THE SETTING SUN.
OVERNIGHT...EXPECTING VFR CONDITIONS TO PREVAIL. THERE IS THE
POTENTIAL FOR SOME FOG ONCE AGAIN AFTER 08Z...BUT NOT AS WIDESPREAD.
AT THIS POINT LEFT THE FOG OUT OF THE FORECAST GIVEN LOW
CONFIDENCE.
&&
.MARINE...
ISSUED AT 406 AM EDT TUE AUG 14 2012
LIGHT WINDS AND LOW WAVES WILL BE THE SEEN THROUGH WEDNESDAY.
HOWEVER SOUTHERN WINDS WILL BE RAMPING UP WEDNESDAY NIGHT AND
THURSDAY...AHEAD AND AS THE FRONT COMES THROUGH. WE MAY APPROACH
SCA CONDITIONS LATE WEDNESDAY NIGHT/EARLY THURSDAY...BUT THERE
WILL BE EVEN STRONG WINDS IN THE CAA BEHIND THE FRONT BY THE END
OF THE WEEK.
&&
.HYDROLOGY...
ISSUED AT 406 AM EDT TUE AUG 14 2012
NEXT DECENT CHANCE OF RAIN WILL COME THURSDAY/THURSDAY NIGHT WITH
A STRONG COLD FRONT. MANY AREAS SHOULD SEE AROUND A HALF INCH OF
RAIN...WITH LOCALIZED HIGHER AMOUNTS. THIS SHOULD NOT CAUSE ANY
WIDESPREAD HYDRO CONCERNS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
202 AM EDT TUE AUG 14 2012
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 407 PM EDT MON AUG 13 2012
WV LOOP AND RAOBS INDICATE UPPER TROUGHS FROM NORTHERN ONTARIO
THROUGH THE WESTERN GREAT LAKES REGION. STRONGEST SHORTWAVES IN
THE MEAN TROUGH ARE OVER NORTHERN ONTARIO AND ALSO SOUTHERN LOWER
MICHIGAN. SHORTWAVE BTWN THE TWO TROUGHS AND SFC TROUGH MERGED UP
WITH LAKE BREEZES OVR CNTRL UPR MICHIGAN EARLIER THIS AFTN TO KICK
OFF ISOLD SHRA AND STORMS. CONVECTIVE DEPTH WAS SHALLOW...BUT RADAR
ESTIMATED PRECIP AMOUNTS UP TO 1-1.5 INCHES SEEMED REASONABLE AS
STORM MOTION WAS SLOW AND EVEN TRIED TO BACKBUILD OVR EXTREME
SOUTH CENTRAL MARQUETTE COUNTY AS ONE STORM BRIEFLY BECAME A RIGHT
MOVER.
AS OF 19Z...THE MESS OF THE SYNOPTIC TROUGH AND LAKE BREEZE
CONVERGENCE BOUNDARY IS ORIENTED FM ROUGHLY WATERSMEET THROUGH JUST
NORTH OF CRYSTAL FALLS AND IRON MOUNTAIN AND EAST TOWARD NEWBERRY
AND SAULT STE MARIE. ISOLD-SCATTERED SHRA/TSRA ARE LOCATED ALONG THE
TROUGH WITH STORM MOTIONS GENERALLY ESE AROUND 15 MPH. BASED ON
RADAR TRENDS AND HRRR MODEL...HIGHLIGHTED HIGHEST POPS EARLY THIS
EVENING OVR SCNTRL UPR MICHIGAN...WITH DIMINISHING TREND BY LATE
EVENING DUE TO LOSS OF DAYTIME INSTABILITY AND LOW-LEVEL
CONVERGENCE. STILL...AT LEAST ISOLD SHRA/TSRA MAY TRY TO STICK
AROUND THROUGH EVEN AFTER MIDNIGHT IN THE FAR SCNTRL WITH LINGERING
WEAKER SHORTWAVE ENERGY OVERHEAD AND STEEPER MID-LEVEL LAPSE RATES
AND H85-H7 MOISTURE. ALL CONVECTION SHOULD BE OUT OF CWA BY LATE
TONIGHT. TEMPS OVER INTERIOR WEST MAY TRY TO FALL OFF INTO THE 40S
LATE TONIGHT WITH A LOWER PWAT MIN LOCATED THERE. A BIT OF WIND AND
POSSIBLE SCT-BKN MID CLOUDS SHOULD KEEP REST OF CWA IN THE 50S.
ON TUESDAY...DAY STARTS OFF WITH THE SCT-BKN MID CLOUDS WITH CU
BUILDUP BY LATE MORNING AS CONVECTIVE TEMPS ARE IN THE LOWER 70S.
SHORTWAVE ON BACK SIDE OF LARGER SCALE TROUGH IN CNTRL SASKATCHEWAN
AND/OR MANITOBA FCST TO SLIDE INTO CNTRL CWA BY MID AFTN. GIVEN
SIMILAR FCST SBCAPES IN THE 700-1000J/KG RANGE COULD SEE REPEAT
PERFORMANCE OF TODAY...OR AT LEAST SOMEWHAT SIMILAR...WITH
ISOLD-SCATTERED SHRA/TSRA FORMING SHORTLY AFTER CONVECTIVE TEMPS
ARE REACHED. MAIN DIFFERENCE IS THE SHORTWAVE IS NOT AS STRONG AND
LOW-LEVEL CONVERGENCE WILL BE STRICTLY DRIVEN BY LAKE BREEZES FM
LAKE SUPERIOR/LAKE MICHIGAN. MSLP/WIND PATTERN POINTS TO AREA BTWN
SAW-IMT-ESC STAND TO SEE BEST COVERAGE OF SHRA/TSRA. FREEZING LEVELS
AROUND 11KFT AGL AND H85-H7 WINDS FAIRLY SIMILAR TO TODAY AS
WELL...SO AGAIN COULD SEE SLOW MOVING STORMS WITH MAIN HAZARDS
LIGHTNING AND HEAVY DOWNPOURS. SMALL HAIL COULD ALSO OCCUR WITH
STRONGEST STORMS. CONVERGENCE WANES BY LATE AFTN SO KEPT WITH IDEA
THAT POPS WILL BE OUT OF THE CWA BY EARLY TUESDAY EVENING.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 407 PM EDT MON AUG 13 2012
TUESDAY NIGHT THROUGH WEDNESDAY AFTERNOON...THE UPPER LEVEL TROUGH
WITH AXIS EXTENDING SOUTHWARD FROM CENTRAL ONTARIO THROUGH THE
EASTERN HALF OF UPPER MI AND INTO THE WESTERN HALF OF LOWER MI WILL
SHIFT EASTWARD OVERNIGHT...REACHING THE LOWER GREAT LAKES BY
WEDNESDAY AFTERNOON. AS THIS TROUGH SHIFTS EASTWARD A SURFACE AND
WEAK UPPER LEVEL RIDGE WILL BUILD INTO THE UPPER GREAT LAKES
REGION...BRIEFLY BRINGING AND END TO THE CHANCES OF PRECIPITATION.
WEDNESDAY EVENING THROUGH FRIDAY NIGHT...AS THE SURFACE RIDGE AND
UPPER LEVEL RIDGE BEGIN TO SHIFT EASTWARD TO THE LOWER GREAT LAKES
ATTENTION WILL THEN TURN TO AN APPROACHING LOW PRESSURE SYSTEM
CENTERED OVER NORTHERN MN...WITH ASSOCIATED UPPER LEVEL TROUGH TO
THE WEST OF THE SURFACE LOW...INDICATED BY BOTH THE
EC/GFS...SUGGESTING THAT THE SURFACE LOW IS EXPECTED TO INTENSIFY.
THE LOW WILL PASS TO THE NORTH OF THE UPPER PENINSULA BY 12Z
THURSDAY AS IT DRAGS A COLD FRONT THROUGH INTO CENTRAL UPPER MI
AROUND THE SAME TIME AS INDICATED BY PLOTTING MSLP/850 THETA
E/SURFACE WINDS. THE MAIN AREA OF PRECIPITATION WILL LIKELY BE
PEGGED TO THE FRONT OF THE COLD FRONT AS THE FORCING APPEARS THE
GREATEST ALONG THIS AREA AS SHOWN BY PLOTTING 500-300MB DIVQ ALONG
WITH 1000-500 RH VALUES. MU CAPE VALUES AREA PROGGED TO BE AROUND
500-800 J/KG OVER MUCH OF THE AREA OVER THE WESTERN HALF OF THE AREA
AROUND 06Z SHIFTING TO THE EAST HALF AROUND 12Z THURSDAY. 0-6 KM
SHEAR VALUES ARE EXPECTED TO BE AROUND 30 TO 35 KNOTS AHEAD OF THE
FRONT WITH VALUES INCREASING TO AROUND 50 KNOTS ALONG AND BEHIND THE
FRONT. SHEAR VALUES BEING MARGINAL FOR SEVERE WEATHER AHEAD OF THE
FRONT ALONG WITH CAPE IN THE HAIL GROWTH ZONE AROUND 100-200 J/KG
WOULD INDICATE ONLY A MARGINAL THREAT OF HAIL. DCAPE VALUES ARE
FAIRLY LOW WITH VALUES AROUND 100-150 J/KG DUE TO A LACK OF DRY AIR
IN THE MID LEVEL. THURSDAY NIGHT THROUGH FRIDAY NIGHT THE UPPER
LEVEL TROUGH WILL REMAIN OVER UPPER MI...WHILE SHIFTING EVER SO
SLOWLY TO THE EAST AS THE SURFACE LOW PULLS OT THE NORTHEAST TO
WESTERN QUEBEC. THE COOLER AIR WRAPPING AROUND THE BACK SIDE OF THE
LOW ALONG WITH DECREASED TEMPERATURES ALOFT...AROUND 4 TO 6C AT
H850...WILL HELP TO INCREASE THE CHANCE OF LAKE EFFECT SHOWERS OVER
THOSE AREAS FAVORED BY NORTH WINDS. HAVE ALSO INCREASED THE WINDS
OVER THE CENTRAL AND EASTERN PORTIONS OF THE LAKE AS CAA KICKS
IN...EXPECT THE STRONGER WINDS TO MIX DOWN AS H850 WINDS ARE AROUND
35 KNOTS. WILL HAVE TO KEEP AN EYE ON THIS THROUGH LATER SHIFTS.
SATURDAY THROUGH MONDAY...BOTH THE EC AND GFS KEEP THE UPPER LEVEL
500MB TROUGH SITUATED OVER MUCH OF THE UPPER GREAT LAKES
REGION...HELPING TO KEEP ON AND OFF CHANCES OF SHOWERS IN THE
FORECAST THROUGH MONDAY AFTERNOON. THE BEST CHANCE OF RAIN SHOWERS
THROUGH THIS PERIOD WOULD BE MONDAY AS A SURFACE LOW APPROACHES THE
AREA FROM THE WEST. MOISTURE THROUGH THIS TIME PERIOD APPEARS TO BE
FAIRLY LIMITED AS A SURFACE HIGH WILL REMAIN JUST TO THE SOUTH OF
THE REGION KEEPING DRY WESTERLY WINDS PUSHING INTO THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 142 AM EDT TUE AUG 14 2012
MAIN ISSUE OVERNIGHT IS FOG. SHALLOW TRANSIENT RADIATIONAL FOG HAS
BEEN A COMMON OCCURRENCE AT KIWD THE LAST FEW NIGHTS...AND IT
APPEARS THAT WILL BE THE CASE AGAIN. EXPECT WIDE VIS FLUCTUATIONS
OVER SHORT PERIODS OF TIME THERE (IFR TO VFR). SINCE RAINFALL
OCCURRED AT KSAW...EXPECT RADIATIONAL FOG (PROBABLE IFR VIS) TO
DEVELOP OVERNIGHT. KCMX SHOULD REMAIN VFR. VFR CONDITIONS WILL
PREVAIL AT KIWD/KCMX TODAY. AT KSAW...LAKE BREEZES AND DAYTIME
HEATING WILL PROBABLY RESULT IN ISOLD/SCT CONVECTION IN CNTRL UPPER
MI. WITH UNCERTAINTY IN COVERAGE/LOCATION OF PCPN...ONLY INCLUDED
VCSH IN THE AFTN. MIGHT SEE SOME TSRA...BUT INSTABILITY WILL BE LESS
THAN YESTERDAY WHEN TSRA WERE MORE NUMEROUS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EDT MON AUG 13 2012
QUIET MARINE WEATHER THROUGH WEDNESDAY AS HIGH PRESSURE SLIDES
OVERHEAD. BY LATER THURSDAY...PASSAGE OF A STRONG COLD FRONT WILL
KICK UP NORTHWEST WINDS TO 25 KTS OVER MUCH OF THE LAKE. WINDS TO 30
KTS ARE EXPECTED OVER CENTRAL AND EASTERN SECTIONS AS COLDER AIRMASS
PUSHES ACROSS THE STILL WARMER WATERS OF LAKE SUPERIOR. THE UNSTABLE
PROFILE WILL LEAD TO BUILDING WAVES THURSDAY NIGHT INTO FRIDAY.
EXPECT THE STRONG WINDS AND HIGH WAVES TO CONTINUE INTO SATURDAY
BEFORE DIMINISHING WITH ARRIVAL OF HIGH PRESSURE. EXPECT THE HIGHER
WAVES TO LEAD TO AN INCREASED RISK OF RIP CURRENTS LATE THURSDAY
THROUGH FRIDAY ALONG THE BEACHES OF EASTERN LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...KEC
AVIATION...ROLFSON
MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1212 AM EDT TUE AUG 14 2012
.SYNOPSIS...
ISSUED AT 311 PM EDT MON AUG 13 2012
RAIN SHOWERS WILL CONTINUE INTO TONIGHT AS LOW PRESSURE MOVES
SOUTH OF LOWER MICHIGAN. FAIR WEATHER WILL FOLLOW FOR TUESDAY AND
WEDNESDAY BUT STRONG THUNDERSTORMS ARE POSSIBLE THURSDAY NIGHT AS
A COLD FRONT MOVES THROUGH.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 311 PM EDT MON AUG 13 2012
LOWERED POPS A BIT TONIGHT AND TUESDAY MORNING. DROPPED POPS FOR
TUESDAY AFTERNOON AND WEDNESDAY NIGHT.
RADAR TRENDS AND HRRR INDICATE THAT MOST OF THE SHOWERS WILL BE
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA WITH MORE SCATTERED
RAIN SHOWERS ACROSS THE NORTH. ADJUSTED POPS TO REFLECT THIS AND
ADDED AREAS OF FOG AFTER MIDNIGHT GIVEN THE EXPECTED LIGHT WINDS
AND HIGH LOW LEVEL RH. LEFT THUNDER OUT OF THE FORECAST DUE TO
MARGINAL INSTABILITY BUT CANNOT RULE OUT AN ISOLATED THUNDERSTORM.
NAM AND GFS CROSS SECTIONS SHOW A QUICKER DEPARTURE OF THE DEEPER
RH ON TUESDAY...SO TRIMMED POPS FOR THE MORNING AND DROPPED THEM
FOR THE AFTERNOON FOR ALL ZONES.
WEAK SFC RIDGING MOVES IN FOR TUESDAY NIGHT AND WEDNESDAY BUT
UPPER TROUGH AMPLIFICATION WILL LEAD TO STRONG SFC COLD FRONT
MOVING TOWARDS LOWER MICHIGAN WEDNESDAY NIGHT. AT HIS POINT IT
APPEARS THE ST ROMS ALONG THE FRONT WILL HOLD OFF UNTIL LATER
THURSDAY...SO DROPPED POPS FOR WEDNESDAY NIGHT.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 311 PM EDT MON AUG 13 2012
MAIN FOCUS OF THE FCST CONTINUES TO BE THE STRONG FRONT EXPECTED TO
MOVE THROUGH THU/THU NIGHT. THE WEEKEND LOOKS COOL AND POTENTIALLY A
LITTLE UNSETTLED WITH TROUGHING HANGING OUT OVER THE REGION. NO REAL
CHANGES WERE MADE TO THE FCST.
PCPN CHANCES WILL BE GRADUALLY INCREASING AT THE BEGINNING OF THE
LONG TERM PERIOD ON THU. THIS OCCURS AS UPPER RIDGING MOVES EAST OF
THE AREA...AND THE STRONG UPPER SYSTEM CURRENTLY MOVING INTO NW
BRITISH COLUMBIA DIGS INTO THE REGION. MODELS CONTINUE TO INDICATE
THAT MOST OF THE PCPN WITH THE SFC FRONT WILL BE RIGHT ALONG AND
JUST BEHIND THE FRONT. THIS IS WHERE THE TAIL END OF THE UPPER
TROUGH AND SFC FRONT OVERLAP.
IT CONTINUES TO LOOK LIKE CLOUDS OUT AHEAD OF THE FRONT WILL
SUPPRESS DIURNAL INSTABILITY SOME. MODELS INDICATE THAT AT LEAST A
FEW HUNDRED J/KG OF ML CAPE WILL BE LIKELY...AND THE GFS /LIKELY
OVERDONE DUE TO SFC DEW POINTS/ SHOWS MORE POTENTIAL INSTABILITY.
DEEP LAYER SHEAR STILL LOOKS TO BE MARGINAL ALONG THE FRONT...WITH
MUCH BETTER VALUES POST-FRONTAL. WE STILL EXPECT THAT STRONG STORMS
WILL BE POSSIBLE DUE TO THE STRENGTH OF THE FRONT AND UPPER TROUGH
THAT COULD COMPENSATE FOR MARGINAL SHEAR AND INSTABILITY.
ONCE THE UPPER TROUGH SUPPORTING THE FRONT MOVES IN...IT LOOKS TO
BECOME ESTABLISHED OVER THE AREA THROUGH THE REMAINDER OF THE
PERIOD. WE WILL SEE SHORT WAVE ENERGY CONTINUE TO DIVE INTO THE MEAN
TROUGH OVER THE GREAT LAKES...HELPING TO REINFORCE IT. THIS WILL
KEEP A CHC OF MAINLY DIURNAL SHOWERS AROUND THROUGH NEXT MON. THE
AREA WILL SEE FALL-LIKE TEMPS IN THE 60S AND TO AROUND 70 FOR THE
WEEKEND. TEMPS WILL SLOWLY MODIFY INTO THE 70S BY MON NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1212 AM EDT TUE AUG 14 2012
CONFIDENCE IS FAIRLY HIGH THAT WIDESPREAD IFR/LIFR CONDITIONS WILL
SETTLE IN TONIGHT AFTER 06Z-08Z. THE LOW CIGS/VSBYS SHOULD LIFT
BY MID MORNING TUESDAY WITH VFR FOLLOWING FOR THE AFTERNOON. A FEW
ISOLD TSTMS COULD DEVELOP TUESDAY AFTERNOON... BUT STILL DID NOT
PUT MENTION OF TS/CB IN THE TAFS SINCE CONFIDENCE IS TOO LOW.
&&
.MARINE...
ISSUED AT 311 PM EDT MON AUG 13 2012
SOME FOG IS POSSIBLE ALONG THE COAST WHERE COOLER WATERS HAVE BEEN
STIRRED UP BY LAST WEEKS STORM. OTHERWISE...NO SIGNIFICANT WEATHER
IS EXPECTED UNTIL THURSDAY OR THURSDAY NIGHT WHEN A COLD FRONT
BRINGS THE CHANCE FOR STRONG THUNDERSTORMS.
&&
.HYDROLOGY...
ISSUED AT 311 PM EDT MON AUG 13 2012
RAINS TODAY AND TONIGHT SHOULD NOT AFFECT RIVER LEVELS. SOME
HEAVIER RAINS ARE POSSIBLE THURSDAY AND THURSDAY NIGHT WITH A HALF
TO AN INCH OF BASIN AVERAGE QPF POSSIBLE.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...NJJ
AVIATION...MEADE
HYDROLOGY...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS DULUTH MN
832 PM CDT WED AUG 15 2012
.UPDATE...THUNDERSTORMS HAVE WEAKENED CONSIDERABLY AS COLD FRONT
MOVES THROUGH A LARGELY STABLE ATMOPSHERE. STILL EXPECT STORMS
TO PERCOLATE THROUGH THE EVENING AHEAD OF THE FRONT UNTIL IT CLEARS
THE FA ROUGHLY AROUND 06Z. SAID STORMS ARE ONLY PRODUCING
BENEFICIAL RAINS AND OCCASIONAL LIGHTNING. NO GUSTY WINDS OR HAIL
HAVE BEEN REPORTED WITH THESE STORMS. HAVE UPDATED TO REMOVE
SEVERE WORDING.
&&
.PREV DISCUSSION... /ISSUED 630 PM CDT WED AUG 15 2012/
AVIATION...00Z TAFS.
COLD FRONT APPROACHING THE WESTERN TERMINALS AT 00Z. THUNDERSTORMS
ARE OCCURRING ALONG AND JUST AHEAD OF THE FRONT. IN VCNTY OF
STORMS...FREQUENT LIGHTNING AND HEAVY RAIN IS EXPECTED WITH
MVFR/IFR CIGS AND IFR/LIFR VSBYS. WELL AHEAD OF THE
STORMS/FRONT...VFR CIGS. THE FRONT WILL MOVE THROUGH THE FA BY
06Z. BEHIND THE FRONT...GUSTY NW WINDS WILL OCCUR WITH SOME ISOLD
SHRA AND MVFR CIGS UNTIL 12Z. AFTER 12Z...THE GUSTY NW WINDS WILL
PERSIST ALONG WITH VFR.
PREV DISCUSSION... /ISSUED 307 PM CDT WED AUG 15 2012/
SHORT TERM...[NOW - THURSDAY NIGHT]
AT 20Z...THERE WAS A POTENT SHORTWAVE IN EASTERN MONTANA AND
WESTERN NORTH DAKOTA APPROACHING THE NORTHERN PLAINS...AND AN
ASSOCIATED MID/UPPER LEVEL TROUGH EXTENDING INTO CENTRAL CANADA.
AN ASSOCIATED SURFACE LOW WAS IN SOUTHEASTERN MANITOBA. A 70 TO 80
KNOT JET WAS ROUNDING THE BASE OF THE MID/UPPER LEVEL TROUGH. A
STRONG COLD FRONT IN ASSOCIATION WITH THE SURFACE LOW STRETCHED
FROM SOUTHEASTERN MANITOBA...THROUGH NORTHWESTERN MINNESOTA...AND
THROUGH EASTERN SOUTH DAKOTA. THE FA HAD SLIGHTLY GUSTY SOUTHERLY
WINDS. TEMPERATURES WERE IN THE MID TO UPPER 70S. DEW POINT
TEMPERATURES WERE STILL IN THE 50S ACROSS MUCH OF THE EASTERN
FA...BUT THEY WERE CLIMBING INTO THE LOW TO MID 60S ACROSS THE
WESTERN FA WITH THE INFLUX OF MOISTURE AHEAD OF THE APPROACHING
COLD FRONT. THERE WERE SHOWERS AND SOME STORMS STRETCHING FROM
SOUTHWESTERN ONTARIO...THROUGH NORTHWESTERN MINNESOTA...AND INTO
EAST CENTRAL NORTH DAKOTA.
THROUGH THIS EVENING...THE COLD FRONT IN WESTERN MINNESOTA IS
EXPECTED TO SWEEP ACROSS THE NORTHLAND LATE THIS AFTERNOON AND
THIS EVENING...AND ITS PASSAGE WILL LIKELY MEAN SHOWERS AND
THUNDERSTORMS FOR MUCH OF THE FA. THE MODELS CONTINUE TO BE IN
REASONABLE AGREEMENT WITH TIMING AND PCPN. THE INFLUX OF WARM
SOUTHERLY FLOW AHEAD OF THE FRONT...COUPLED WITH THE EXPECTED
SHEAR AND CAPE...COULD RESULT IN SOME SEVERE THUNDERSTORMS.
CONTINUE TO THINK THAT MORE DISCREET SHOWERS AND STORMS IN WESTERN
MINNESOTA THIS AFTERNOON WILL BEGIN TO MOVE INTO NORTHEASTERN
MINNESOTA LATE THIS AFTERNOON AND TAKE ON A MORE LINEAR STRUCTURE.
THIS IS BACKED UP BY RECENT RUNS OF THE WRF AND HRRR MODELS. THIS
WOULD SUGGEST THAT DAMAGING WINDS ARE THE GREATEST THREAT FOR THE
STORMS TONIGHT...AND THAT IS IN AGREEMENT WITH THE SLIGHT RISK OF
SEVERE WEATHER CURRENTLY OUT FROM THE STORM PREDICTION CENTER AND
ITS EMPHASIS ON DAMAGING WINDS. LARGE HAIL AND BRIEF DOWNPOURS OF
RAIN ARE BOTH CERTAINLY POSSIBLE TOO. MIXED LAYER CAPE VALUES OF
1000 TO 2000 J/KG...DEEP LAYER SHEAR OF 30 TO 50 KNOTS...AND
PRECIPITABLE WATER VALUES OF AROUND 1.5 INCHES ARE EXPECTED THIS
AFTERNOON WHEN THE COLD FRONT MOVES INTO THE WESTERN FA. SINCE
THIS COLD FRONT WILL BE MOVING FAIRLY QUICKLY...HEAVY RAIN IS NOT
TOO MUCH OF AN ISSUE DUE TO LACK OF THUNDERSTORMS RESIDENCE TIME
OR TRAINING. HOWEVER...THERE COULD CERTAINLY BE BRIEF DOWNPOURS
WITH THE RAIN. MUCH OF THE FA HAS BEEN GIVEN ABOUT A QUARTER TO
HALF INCH OF RAIN FOR THE FORECAST THROUGH THIS EVENING.
LATE TONIGHT...MUCH COOLER AIR WILL SWOOP INTO THE NORTHLAND LATE
TONIGHT IN THE WAKE OF THE FRONT. ANY REMAINING PCPN SHOULD
TRANSITION TO SHOWERS...BUT THERE MAY BE SOME LINGERING THUNDER
ACROSS THE FAR EASTERN FA.
THURSDAY...IT LOOKS LIKE A SOMEWHAT DREARY SUMMER DAY ACROSS THE
NORTHLAND. PARTLY TO MOSTLY CLOUDY SKIES...GUSTY NORTHWEST
WINDS...AND MUCH COOLER TEMPERATURES ARE EXPECTED IN THE WAKE OF
THE FRONT. MODEL SOUNDINGS SUGGEST WIND GUSTS OF 20 TO 30 MPH AT
TIMES. SHOWERS ARE POSSIBLE ACROSS NORTHERN MINNESOTA. THERE MAY
BE SOME LATE DAY SUNSHINE ACROSS THE WESTERN FA.
THURSDAY NIGHT...THE CLOUDS SHOULD GRADUALLY CLEAR AND THE WINDS
RELAX AS HIGH PRESSURE MOVES INTO THE NORTH CENTRAL US.
LONG TERM...[FRIDAY - TUESDAY]
PATTERN CHANGE TO A STRONGER UPPER LEVEL TROF ANCHORED OVER THE
CENTRAL GREAT LAKES THIS WEEKEND AND EARLY NEXT WEEK WILL LEAVE
THE DULUTH CWA UNDERNEATH COOL NW FLOW ALOFT AND WHAT WILL
PROBABLY FEEL LIKE EARLY FALL WEATHER AT TIMES. AS IS COMMON IN
PREVAILING NW FLOW ALOFT..A SERIES OF WEAK BUT AMPLIFYING
DISTURBANCES WILL DIVE SOUTHEASTWARD ACROSS OUR AREA INTO THE MAIN
TROF AXIS DURING THE SAT-MON TIME FRAME. RELATIVELY COOL TEMPS
ALOFT AND STEEP LOW-MID LEVEL LAPSE RATES WITH ANY DAYTIME SUN
SHOULD RESULT IN ISOLATED/SCATTERED SHOWERS AND PERHAPS A FEW
T-STORMS EACH DAY FRIDAY THRU SUNDAY. MODELS TYPICALLY HAVE A HARD
TIME RESOLVING INDIVIDUAL DISTURBANCES IN THIS FLOW REGIME BEYOND
48-60 HOURS..AND THIS SEEMS TO BE THE CASE THRU MONDAY AS THE WAVE
THAT SEEMS BEST RESOLVED RIGHT NOW TIMING/PLACEMENT WISE IS ON
FRIDAY.
EARLY NEXT WEEK LOOKS FAIRLY TRANQUIL WITH A SLOW WARMING TREND OF
A FEW DEGREES EACH DAY AS GREAT LAKES TROF SLOWLY DE-AMPLIFIES
AND FLOW ALOFT BECOMES MORE WESTERLY. THIS SHOULD EVENTUALLY ALLOW
MOISTURE TO SLOWLY INCREASE BY THE END OF THE 7 DAY FORECAST
PERIOD..WITH AT LEAST SMALL CHANCES FOR SHOWERS/TSTMS RETURNING
FROM WED/THUR.
&&
.POINT TEMPS/POPS...
DLH 54 63 45 69 / 70 10 0 30
INL 51 61 41 72 / 50 30 10 30
BRD 54 66 45 71 / 50 10 0 10
HYR 57 68 44 69 / 50 10 0 20
ASX 59 68 47 72 / 50 10 10 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GSF
AREA FORECAST DISCUSSION
NWS DULUTH MN
630 PM CDT WED AUG 15 2012
.AVIATION...00Z TAFS.
COLD FRONT APPROACHING THE WESTERN TERMINALS AT 00Z. THUNDERSTORMS
ARE OCCURRING ALONG AND JUST AHEAD OF THE FRONT. IN VCNTY OF
STORMS...FREQUENT LIGHTNING AND HEAVY RAIN IS EXPECTED WITH
MVFR/IFR CIGS AND IFR/LIFR VSBYS. WELL AHEAD OF THE
STORMS/FRONT...VFR CIGS. THE FRONT WILL MOVE THROUGH THE FA BY
06Z. BEHIND THE FRONT...GUSTY NW WINDS WILL OCCUR WITH SOME ISOLD
SHRA AND MVFR CIGS UNTIL 12Z. AFTER 12Z...THE GUSTY NW WINDS WILL
PERSIST ALONG WITH VFR.
&&
.PREV DISCUSSION... /ISSUED 307 PM CDT WED AUG 15 2012/
SHORT TERM...[NOW - THURSDAY NIGHT]
AT 20Z...THERE WAS A POTENT SHORTWAVE IN EASTERN MONTANA AND
WESTERN NORTH DAKOTA APPROACHING THE NORTHERN PLAINS...AND AN
ASSOCIATED MID/UPPER LEVEL TROUGH EXTENDING INTO CENTRAL CANADA.
AN ASSOCIATED SURFACE LOW WAS IN SOUTHEASTERN MANITOBA. A 70 TO 80
KNOT JET WAS ROUNDING THE BASE OF THE MID/UPPER LEVEL TROUGH. A
STRONG COLD FRONT IN ASSOCIATION WITH THE SURFACE LOW STRETCHED
FROM SOUTHEASTERN MANITOBA...THROUGH NORTHWESTERN MINNESOTA...AND
THROUGH EASTERN SOUTH DAKOTA. THE FA HAD SLIGHTLY GUSTY SOUTHERLY
WINDS. TEMPERATURES WERE IN THE MID TO UPPER 70S. DEW POINT
TEMPERATURES WERE STILL IN THE 50S ACROSS MUCH OF THE EASTERN
FA...BUT THEY WERE CLIMBING INTO THE LOW TO MID 60S ACROSS THE
WESTERN FA WITH THE INFLUX OF MOISTURE AHEAD OF THE APPROACHING
COLD FRONT. THERE WERE SHOWERS AND SOME STORMS STRETCHING FROM
SOUTHWESTERN ONTARIO...THROUGH NORTHWESTERN MINNESOTA...AND INTO
EAST CENTRAL NORTH DAKOTA.
THROUGH THIS EVENING...THE COLD FRONT IN WESTERN MINNESOTA IS
EXPECTED TO SWEEP ACROSS THE NORTHLAND LATE THIS AFTERNOON AND
THIS EVENING...AND ITS PASSAGE WILL LIKELY MEAN SHOWERS AND
THUNDERSTORMS FOR MUCH OF THE FA. THE MODELS CONTINUE TO BE IN
REASONABLE AGREEMENT WITH TIMING AND PCPN. THE INFLUX OF WARM
SOUTHERLY FLOW AHEAD OF THE FRONT...COUPLED WITH THE EXPECTED
SHEAR AND CAPE...COULD RESULT IN SOME SEVERE THUNDERSTORMS.
CONTINUE TO THINK THAT MORE DISCREET SHOWERS AND STORMS IN WESTERN
MINNESOTA THIS AFTERNOON WILL BEGIN TO MOVE INTO NORTHEASTERN
MINNESOTA LATE THIS AFTERNOON AND TAKE ON A MORE LINEAR STRUCTURE.
THIS IS BACKED UP BY RECENT RUNS OF THE WRF AND HRRR MODELS. THIS
WOULD SUGGEST THAT DAMAGING WINDS ARE THE GREATEST THREAT FOR THE
STORMS TONIGHT...AND THAT IS IN AGREEMENT WITH THE SLIGHT RISK OF
SEVERE WEATHER CURRENTLY OUT FROM THE STORM PREDICTION CENTER AND
ITS EMPHASIS ON DAMAGING WINDS. LARGE HAIL AND BRIEF DOWNPOURS OF
RAIN ARE BOTH CERTAINLY POSSIBLE TOO. MIXED LAYER CAPE VALUES OF
1000 TO 2000 J/KG...DEEP LAYER SHEAR OF 30 TO 50 KNOTS...AND
PRECIPITABLE WATER VALUES OF AROUND 1.5 INCHES ARE EXPECTED THIS
AFTERNOON WHEN THE COLD FRONT MOVES INTO THE WESTERN FA. SINCE
THIS COLD FRONT WILL BE MOVING FAIRLY QUICKLY...HEAVY RAIN IS NOT
TOO MUCH OF AN ISSUE DUE TO LACK OF THUNDERSTORMS RESIDENCE TIME
OR TRAINING. HOWEVER...THERE COULD CERTAINLY BE BRIEF DOWNPOURS
WITH THE RAIN. MUCH OF THE FA HAS BEEN GIVEN ABOUT A QUARTER TO
HALF INCH OF RAIN FOR THE FORECAST THROUGH THIS EVENING.
LATE TONIGHT...MUCH COOLER AIR WILL SWOOP INTO THE NORTHLAND LATE
TONIGHT IN THE WAKE OF THE FRONT. ANY REMAINING PCPN SHOULD
TRANSITION TO SHOWERS...BUT THERE MAY BE SOME LINGERING THUNDER
ACROSS THE FAR EASTERN FA.
THURSDAY...IT LOOKS LIKE A SOMEWHAT DREARY SUMMER DAY ACROSS THE
NORTHLAND. PARTLY TO MOSTLY CLOUDY SKIES...GUSTY NORTHWEST
WINDS...AND MUCH COOLER TEMPERATURES ARE EXPECTED IN THE WAKE OF
THE FRONT. MODEL SOUNDINGS SUGGEST WIND GUSTS OF 20 TO 30 MPH AT
TIMES. SHOWERS ARE POSSIBLE ACROSS NORTHERN MINNESOTA. THERE MAY
BE SOME LATE DAY SUNSHINE ACROSS THE WESTERN FA.
THURSDAY NIGHT...THE CLOUDS SHOULD GRADUALLY CLEAR AND THE WINDS
RELAX AS HIGH PRESSURE MOVES INTO THE NORTH CENTRAL US.
LONG TERM...[FRIDAY - TUESDAY]
PATTERN CHANGE TO A STRONGER UPPER LEVEL TROF ANCHORED OVER THE
CENTRAL GREAT LAKES THIS WEEKEND AND EARLY NEXT WEEK WILL LEAVE
THE DULUTH CWA UNDERNEATH COOL NW FLOW ALOFT AND WHAT WILL
PROBABLY FEEL LIKE EARLY FALL WEATHER AT TIMES. AS IS COMMON IN
PREVAILING NW FLOW ALOFT..A SERIES OF WEAK BUT AMPLIFYING
DISTURBANCES WILL DIVE SOUTHEASTWARD ACROSS OUR AREA INTO THE MAIN
TROF AXIS DURING THE SAT-MON TIME FRAME. RELATIVELY COOL TEMPS
ALOFT AND STEEP LOW-MID LEVEL LAPSE RATES WITH ANY DAYTIME SUN
SHOULD RESULT IN ISOLATED/SCATTERED SHOWERS AND PERHAPS A FEW
T-STORMS EACH DAY FRIDAY THRU SUNDAY. MODELS TYPICALLY HAVE A HARD
TIME RESOLVING INDIVIDUAL DISTURBANCES IN THIS FLOW REGIME BEYOND
48-60 HOURS..AND THIS SEEMS TO BE THE CASE THRU MONDAY AS THE WAVE
THAT SEEMS BEST RESOLVED RIGHT NOW TIMING/PLACEMENT WISE IS ON
FRIDAY.
EARLY NEXT WEEK LOOKS FAIRLY TRANQUIL WITH A SLOW WARMING TREND OF
A FEW DEGREES EACH DAY AS GREAT LAKES TROF SLOWLY DE-AMPLIFIES
AND FLOW ALOFT BECOMES MORE WESTERLY. THIS SHOULD EVENTUALLY ALLOW
MOISTURE TO SLOWLY INCREASE BY THE END OF THE 7 DAY FORECAST
PERIOD..WITH AT LEAST SMALL CHANCES FOR SHOWERS/TSTMS RETURNING
FROM WED/THUR.
&&
.POINT TEMPS/POPS...
DLH 54 63 45 69 / 70 10 0 30
INL 51 61 41 72 / 70 30 10 30
BRD 54 66 45 71 / 70 10 0 10
HYR 57 68 44 69 / 60 10 0 20
ASX 59 68 47 72 / 60 10 10 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
325 AM CDT TUE AUG 14 2012
.DISCUSSION...
SEVERAL WEAK SHRTWV/S ACROSS THE DAKOTAS ARE CAUSING SOME CONCERNS
WITH ISOLD/SCT SHRA/TSRA IN SW/WC MN DURING THE AFTN/EVENING AS
AMPLE MID-LEVEL MOISTURE BEGINS TO ADVECT INTO THE AREA.
WV IMAGERY HAS THE MAIN SHRTWV ACROSS SW SD EARLIER THIS MORNING
WHICH IS ASSOCIATED WITH A DECAYING MCS FROM MT. BUT...THE FACT
THAT SOME SHRA CONTINUED AHEAD OF ANOTHER SHRTWV EMBEDDED IN
WESTERN ND DOES ALLOW FOR AT LEAST SOME ISOLD POPS IN WC/SW MN
DURING THE AFTN/EVENING OR BEFORE A MORE ESTABLISHED LLJ DEVELOPS
LATER TONIGHT IN THE DAKOTAS/WESTERN MN.
LATEST ECMWF HAS DEVELOPED A MORE SIGNIFICANT THERMAL BOUNDARY
ACROSS NE/SD LATER TODAY...WHICH WILL LEAD TO BETTER DYNAMICS
ACROSS SW MN AFT DARK AS THE LLJ DEVELOPS. EVEN THE LATEST
VWP/PROFILER NETWORK AT 85H IN NE INDICATED A BETTER LLJ THIS
MORNING COMPARED TO THE MODELS 6 HR FORECAST ACROSS SW SD.
THEREFORE...AM LEANING TOWARD HIGHER POPS IN SW/WC MN THIS
AFTN/EVENING...THEN SPREADING THIS ACTIVITY ACROSS S MN DURING THE
OVERNIGHT HRS...BEFORE THE NOCTURNAL LLJ DECREASES WED MORNING.
THIS SCENARIO ALSO PLAYS HAVOC ON TEMPS FOR WED WHICH MAY BE
COOLER IF MORE CLOUD COVER IS EXPECTED...ESPECIALLY IN THE NE FA.
OVERALL...THE BEST CHC OF WIDESPREAD CONVECTION IS WED
EVENING...WITH THE ACTIVITY QUICKLY MOVING NE/E DURING THE
OVERNIGHT HRS. SOME LINGERING SHRA ARE POSSIBLE IN THE FAR E FA
BEFORE NOON THU...BUT MOST OF THE ACTIVITY SHOULD BE DONE BY 12Z.
AS PER SVR WX...AMPLE 0-6KM WIND SHEAR AND CAPES ARND 2000 J/KG
WED EVENING SHOULD BE ENOUGH TO GENERATE ORGANIZED CONVECTIVE
STORMS. THE BEST 0-1KM SHEAR IS WELL AHEAD OF THE MAIN FRONTAL
BOUNDARY. HOWEVER...IF AN ESTABLISHED COMPLEX OF TSRA
DEVELOPS...THERE IS ENOUGH SHEAR TO POSSIBLY GENERATE A COLD POOL
LEADING TO A BOW ECHO SCENARIO. WILL HIGHLIGHT THE MORNING
HWO FOR THE SVR WX POTENTIAL...ALSO SEE THE LATEST SPC DAY2 OUTLOOK.
AFTER THU...CHC/S OF PRECIPITATION REMAIN LOW WITH A PREDOMINATE
W/NW FLOW ALOFT. TEMPS WILL REMAIN BLW NORMAL FOR THE MOST PART
THRU SUNDAY...WITH SOME MODIFICATIONS EARLY NEXT WEEK AS A MORE
WESTERNLY FLOW DEVELOPS...AND WARMER AIR FROM THE PLAINS BEGINS TO
SPILL ACROSS THE MIDWEST.
EVEN THOUGH SEVERAL SHRTWV/S DIVE S/SE FROM THIS NW FLOW
DEVELOPING THIS WEEKEND...MOISTURE WILL LIKELY BE LIMITED DUE TO
THE STRENGTH OF THE DRIER AIR MASS AND HOW FAR SOUTH THE FRONTAL
BOUNDARY MOVES TO THE SE U.S. OVER THE WEEKEND ..JLT..
&&
.AVIATION.../06Z TAF ISSUANCE/
PREVALENT SURFACE HIGH PRESSURE WILL YIELD LIGHT WINDS AND VFR
CONDITIONS THROUGH THE PERIOD...WITH THE EXCEPTION OF THE
POSSIBILITY OF A PERIOD OF FOG BETWEEN 09Z AND 13Z. CONCERN MAINLY
LIES OVER WEST CENTRAL WI AND SOUTH CENTRAL MN /KEAU-KRNH-
KRWF/...WHERE MEASURABLE PRECIP FELL MONDAY AND THE RAP INDICATES
DEWPOINT DEPRESSIONS DECREASE TO AROUND 2 OVERNIGHT. DO NOT THINK
IT WILL BE A CRYSTAL CLEAR SKY OVERNIGHT...WITH SHORT TERM MODELS
INDICATING LINGERING MOISTURE CIRCA 850MB...WHICH WAS CONFIRMED BY THE
00Z MPX RAOB. THEREFORE EXPECT SCATTERED CLOUDS AROUND 6K FEET
MIGHT ABATE SOME OF THE FOG RISK...PARTICULARLY AT KRWF. HAVE
THEREFORE MAINTAINED ONLY MINOR MVFR VSBY REDUCTIONS AT KRWF AND
KRNH. LIFR VSBYS OR EVEN BRIEF VLIFR VSBYS APPEAR LIKELY AT KEAU WHERE
A HALF INCH OF RAIN FELL MONDAY AFTERNOON. THE REMAINDER OF THE
TAF PERIOD WILL FEATURE FEW-SCT CUMULUS NEAR KRNH AND KEAU...AND
INCREASING MID/HIGH CLOUDS FROM WEST TO EAST AS THE NEXT SYSTEM
APPROACHES.
KMSP...VFR THROUGH THE PERIOD WITH LIGHT AND VARIABLE WINDS UNDER
THE INFLUENCE OF HIGH PRESSURE. DIRECTIONAL COMPONENT WILL BE
NORTHWESTERLY ON TUESDAY. WINDS WILL BACK TO SOUTH/SOUTHEAST IN DIRECTION
AND MID CLOUDS WILL BEGIN TO INCREASE AFTER 00Z WED AS A SURFACE
TROUGH APPROACHES.
/OUTLOOK/
.WEDNESDAY...VFR WITH MVFR AND TSRA POSSIBLE EARLY MORNING AND
AGAIN AT NIGHT. NIGHT COLD FROPA BTWN 00Z AND 06Z. WINDS S AT
10G15KTS SHIFTING TO NW 10G15KTS WITH THE FROPA.
.THURSDAY...VFR. WINDS BECOMING NW AT 15G25KTS.
.FRI...VFR. WINDS NW AOB 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JLT/LS
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1014 PM CDT WED AUG 15 2012
.UPDATE...
ISSUED AT 941 PM CDT WED AUG 15 2012
WIDELY SCATTERED SHOWERS AND STORMS DEVELOPING ACROSS ERN IA AND
NWRN IL WHERE THERE WAS 850 MB WAA AND THETA E ADVECTION NEAR NOSE
OF SWLY LOW LEVEL JET...AHEAD OF APPROACHING TROUGH. THIS
ACTIVITY WILL LIKELY CONTINUE LATE TGT AND MAY SHIFT SEWD INTO
NERN MO AND W CNTRL IL. WILL LIKELY HAVE ADDITIONAL CONVECTIVE
DEVELOPMENT FURTHER W ACROSS IA WITH APPROACH OF SHORTWAVE TROUGH
OVER THE NRN PLAINS AND ASSOCIATED COLD FRONT MOVING SEWD THROUGH
NWRN IA AND SERN NEBRASKA. IT APPEARS THAT THE SHOWERS AND STORMS
WILL REMAIN N AND W OF THE STL AREA THROUGH THE LATE NGT HOURS.
LOW TEMPERATURES TGT WILL BE WARMER THAN THE PREVIOUS NIGHT WITH
INCREASING CLOUD COVER... STRONGER SFC WINDS...RISING SFC DEW
POINTS AND 850 MB TEMPERATURES RISING TO 19-21 DEGREES C BY 12Z THU.
GKS
&&
.SHORT TERM...
ISSUED AT 137 PM CDT WED AUG 15 2012
(TONIGHT)
MAIN CONCERN DEALS WITH RAIN CHANCES THROUGH TONIGHT. PREFER THE
NAM`S DEPICTION OF MASS FIELDS AND QPF THROUGH 12Z AS IT HAS BETTER
CONTINUITY AND THE GFS IS SHOWING QUITE A BIT OF CONVECTIVE FEEDBACK
DEVELOPING BETWEEN 00-06Z. STILL EXPECT TO BE MAINLY DRY THROUGH
06Z AS SHORTWAVE RIDGING WILL STILL BE WORKING INTO THE AREA.
THEREAFTER...THERE WILL BE INCREASED 925-850MB MOISTURE CONVERGENCE
ON THE NOSE OF A 40KT LOW LEVEL JET. HAVE KEPT SLIGHT CHANCES AFTER
06Z...MAINLY OVER CENTRAL AND NORTHEAST MISSOURI INTO WEST CENTRAL
ILLINOIS. FORECAST SOUNDINGS DO SHOW THAT THERE WILL STILL A BIT OF
CINH EVEN ALOFT WHICH WILL LIMIT OVERALL COVERAGE OF -TSRA/-SHRA. I
DID INCREASE TO LOW CHANCE POPS OVER THE FAR NORTHERN CWA BETWEEN
09-12Z AS THIS AREA BEGINS TO SEE AN INCREASE IN LARGE SCALE ASCENT
AHEAD OF SHORTWAVE TROUGH. GOING LOWS ARE A GOOD COMPROMISE OF THE
NAM/GFS MOS TEMPS...SO LEFT PRETTY MUCH AS IS.
BRITT
&&
.LONG TERM...
ISSUED AT 137 PM CDT WED AUG 15 2012
(TOMORROW THROUGH NEXT TUESDAY)
THE PRIMARY FCST PROBLEM FOR TOMORROW AND TOMORROW NIGHT IS PCPN
CHCS AND SVR WX POTENTIAL. VORT MAX LOCATED OVER MT AND ALBERTA AT
12Z WED WILL DEEPEN AS IT MOVES ALONG THE US/CANADIAN BORDER TODAY.
ASSOCIATED SFC LOW SHOULD BE LOCATED IN WRN ONT AT 12Z THU WITH A
CDFNT EXTENDING SWWD THROUGH WI INTO IA/MO/KS. MODELS CONTINUE TO
SHOW FAVORABLE TIMING FOR WIDESPREAD TSRA WITH AFTN FROPA HOWEVER
OUTFLOW BDRYS FROM OVERNIGHT CONVECTION FARTHER NORTH MIGHT PUSH THE
EFFECTIVE BDRY FARTHER SOUTH THAN INITIALLY ANTICIPATED. NEXT
QUESTION IS SVR WX POTENTIAL. UNFAVORABLE FACTORS INCLUDE LIMITED
DYNAMICS THIS FAR SOUTH OF THE UPPER VORT MAX...0-6 KM SHEAR FCSTS
OF LTE 20 KTS SOUTH OF THE CDFNT...AND A LAG OF SEVERAL HOURS
BETWEEN SFC FROPA AND UPPER LEVEL FORCING FOR ASCENT.
HOWEVER...STRONG SFC CONVERGENCE ALONG THE CDFNT AND 1500-2000 J/KG
OF CAPE EXPECTED AHEAD OF THE FRONT SHOULD PARTIALLY COMPENSATE FOR
THE LOWER SHEAR VALUES AND LIMITED DYNAMICS. ATTM IT LOOKS LIKE THE
PRIMARY THREAT WILL BE DAMAGING WIND GUSTS DUE TO THE STEEP LOW LEVEL
LAPSE RATES /ESPECIALLY ACROSS THE SERN HALF OF THE CWA/ ALTHOUGH
HAIL WILL ALSO BE POSSIBLE WITH THE STRONGER UPDRAFTS.
COOLER WX EXPECTED FOR FRI THROUGH SUN AS A SFC HIGH PRESSURE
CENTER BUILDS IN BEHIND THE FRONT WITH THE RIDGE AXIS OVERHEAD BY
12Z SAT. GOOD RADIATIONAL COOLING CONDITIONS WITHIN A DRIER POSTFNTL
AIR MASS ON FRI NIGHT SHOULD PRODUCE OVERNIGHT LOWS IN THE 50S
ACROSS THE CWA. H85 TEMPERATURES OF 10-12 DEG C SUPPORT HIGHS IN THE
MID 70S TO LOWER 80S ON SAT/SUN. A VORT LOBE ROTATING AROUND THE ERN
CONUS LONGWAVE TROF SHOULD MOVE THROUGH MO/IL ON SAT AFTN/EVE
LEADING TO INCREASED CLOUDINESS AND POSSIBLY PCPN DEPENDING ON
TIMING AND MOISTURE AVAILABILITY. MAINTAINED A DRY FCST FOR NOW
GIVEN TIMING UNCERTAINTY. MODELS AGREE THAT THE CWA WILL BE UNDER NW
FLOW ALOFT THROUGH SUN NIGHT BUT SOLUTIONS BEGIN TO DIVERGE AFTER
MON. GENERALLY EXPECT A WARMING TREND BY LATE NEXT WEEK AS THE DEEP
TROF OVER THE ERN CONUS LIFTS AND A RIDGE OVER THE WRN CONUS SHIFTS
EWD.
KANOFSKY
&&
.AVIATION...
ISSUED AT 532 PM CDT WED AUG 15 2012
VFR CONDITIONS THIS EVENING WITH MOSTLY CLEAR SKIES AND SOUTHERLY
WINDS UP TO 10KTS. CONVECTION EXPECTED TO DEVELOP TO THE NORTHWEST
ALONG AN APPROACHING COLD FRONT. MANY QUESTIONS SURROUND HOW
THESE THUNDERSTORMS WILL IMPACT OUR REGION LATE TONIGHT AND EARLY
THURSDAY MORNING. LATEST NAM AND 4KM NCEP WRF SHOW CONVECTION AND
OUTFLOW BOUNDARY REACHING ALL TERMINALS BY 12Z THURSDAY MORNING.
THINK THIS MAY BE A BIT TOO AGRESSIVE...AND HAVE ONLY ADJUSTED THE
FORECAST FOR KUIN AT THIS TIME TO ACCOUNT FOR THIS SCENARIO.
HOPEFULLY LATER HRRR RUNS AND 00Z NAM RUN LEND CONFIDENCE TO
CONVECTIVE TRENDS. FOR NOW STILL THINK BEST CHANCE OF
THUNDERSTORMS AT KCOU AND ST. LOUIS METRO TAFS WILL BE WITH COLD
FRONTAL PASSAGE DURING THE AFTERNOON.
SPECIFICS FOR KSTL...
VFR CONDITIONS MUCH OF THE NIGHT...WITH HIGH/MID CLOUD FROM
APPROACHING CONVECTION OVERSPREADING THE TERMINAL BY DAYBREAK.
STILL BELIEVE BEST CHANCE OF THUNDERSTORMS WILL BE IN THE
AFTERNOON WITH COLD FRONT...BUT CANT RULE OUT THE SCENARIO THAT
NOCTURNAL CONVECTION/OUTFLOW MAKES IT TO THE TERMINAL AROUND 12Z.
CVKING
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS HASTINGS NE
939 PM CDT WED AUG 15 2012
.UPDATE...HAVE INCREASINGLY BEEN LOSING CONFIDENCE IN THUNDERSTORM
DEVELOPMENT THIS EVENING. THE HRRR AND 00Z NAM CONTINUE TO TRY AND
DEVELOP CONVECTION ALONG THE FRONT...BUT THUS FAR THIS HAS NOT
MATERIALIZED AND IT SEEMS LESS LIKELY THAT IT WILL EVER
MATERIALIZE IN AT LEAST AN IMPACTFUL WAY. IT IS APPEARING MORE
LIKELY THAT MOST AREAS WILL ONCE AGAIN SEE A DRY NIGHT...OR MAYBE
A FEW POST FRONTAL SHOWERS DURING THE EARLY MORNING HOURS. EVEN IF
POST FRONTAL SHOWERS DEVELOP...THEY WILL LIKELY NOT BE BIG
PRECIPITATION PRODUCERS. THEREFORE...HAD TO DRASTICALLY CUT POPS
FOR THE REMAINDER OF TONIGHT FOR MOST NEBRASKA ZONES. THERE HAVE
BEEN A FEW THUNDERSTORMS OVER KANSAS ZONES AND HAVE ACTUALLY
INCREASED POPS ACROSS OUR FAR SOUTHERN KANSAS ZONES.
&&
.PREV DISCUSSION... /ISSUED 700 PM CDT WED AUG 15 2012/
AVIATION...00Z KGRI TAF. A COLD FRONT WILL PASS THROUGH KGRI
BETWEEN 8 AND 9 PM. THE WIND WILL ESSENTIALLY BE LIGHT AND
VARIABLE UNTIL AFTER THE COLD FRONT PASSES THROUGH AND THEN WILL
QUICKLY PICK UP OUT OF THE NORTH AND COULD BE RATHER GUSTY
ESPECIALLY THE FIRST FEW HOURS AFTER THE FRONTAL PASSAGE. THERE
WILL ALSO BE A CHANCE OF THUNDERSTORMS ASSOCIATED WITH THE FRONTAL
PASSAGE. AS OF 645PM THERE WAS SOME VERTICAL DEVELOPMENT IN THE CU
FIELD NEAR LOUP CITY. THE WIND WILL REMAIN OUT OF THE NORTH
THROUGH THE DAY TOMORROW.
PREV DISCUSSION... /ISSUED 338 PM CDT WED AUG 15 2012/
SHORT TERM...THROUGH 00Z FRIDAY. MORNING UPPER AIR ANALYSIS
INDICATES UPPER LEVEL RIDGING OVER THE SOUTHWESTERN
CONUS...TROUGHING OVER THE EAST...AND A MID LEVEL SHORT WAVE OVER
SOUTH-CENTRAL CANADA AND THE NORTHERN PLAINS. UPPER LEVEL JET
ENERGY IS ALSO NOTED MEANDERING NORTH AND SOUTH FROM SOUTHWESTERN
AND SOUTHERN CANADA...AS WELL AS THE NORTHERN PLAINS ON INTO THE
EASTERN CONUS...AND A ~50KT MID LEVEL JET STREAK IS NOTED OVER
PORTIONS OF THE NORTHERN PLAINS ON THE SOUTH/SOUTHEAST SIDE OF THE
APPROACHING MID LEVEL SHORT WAVE. WATER VAPOR IMAGERY INDICATES A
DEVELOPING TROPICAL TAP OVER THE SOUTHWESTERN CONUS...BUT THIS
MOISTURE REMAINS RELEGATED TO OUR SOUTHWEST WITH MID LEVEL
MOISTURE OVER OUR AREA PRIMARILY BEING PULLED IN FROM THE PACIFIC
NORTHWEST BY THE APPROACHING MID LEVEL SHORT WAVE. A SURFACE LOW
IS NOTED OVER NORTHERN MINNESOTA...AHEAD OF THE MID LEVEL SHORT
WAVE...AND A COLD FRONT EXTENDS SOUTH/SOUTHWESTWARD FROM THE LOW
ACROSS THE DAKOTAS INTO CENTRAL NEBRASKA...AND THEN INTO
NORTHWESTERN KANSAS AND EASTERN COLORADO. AS OF 19Z THIS FRONT WAS
NOTED EXTENDING FROM NEAR KANW...TO KTIF...KLBF AND NEAR KIML. LOW
LEVEL FLOW REMAINS FROM THE SOUTH ACROSS MUCH OF OUR CWA AS A
RESULT...WITH A NORTHWESTERLY LOW LEVEL WIND FIELD NOTED BEHIND
THE LOW LEVEL BAROCLINIC ZONE ACROSS THE HIGH PLAINS. VISIBLE
SATELLITE IMAGERY INDICATES VERY LITTLE IN THE WAY OF CLOUD COVER
ACROSS NEBRASKA...BUT HIGH LEVEL CLOUDS AHEAD OF THE MID LEVEL
SHORT WAVE ARE BEGINNING TO ENTER THE STATE FROM SOUTH DAKOTA.
SMOKE IS ALSO EVIDENT ON VISIBILITY SATELLITE IMAGERY...ORIGINATING
FROM THE WILDFIRES CURRENTLY BURNING ACROSS WESTERN PORTIONS OF
THE CONUS.
SHORT TERM GUIDANCE CONTINUES TO SUGGEST THE NORTHERN PLAINS MID
LEVEL SHORT WAVE WILL CONTINUE MOVING EAST/SOUTHEAST TONIGHT INTO
TOMORROW. THIS WILL ALLOW THE SURFACE LOW...CURRENTLY OVER
NORTHERN MINNESOTA...TO PUSH EAST THUS ALLOWING THE LOW LEVEL
BAROCLINIC ZONE TO ALSO SWEEP EAST ACROSS OUR CWA. QPF FIELDS FROM
THE 15/12Z NAM AND 4KM WRF-NMM...AS WELL AS THE 15/14Z HRRR
SUGGEST CONVECTION WILL INITIATE NEAR OUR WEST/NORTHWESTERN CWA
ALONG THE LOW LEVEL BAROCLINIC ZONE AROUND 00Z. ISOLATED TO
PERHAPS SCATTERED PRECIPITATION IS THEN EXPECTED TO PUSH
EAST/SOUTHEAST ACROSS THE CWA. THE BEST DPVA AND MID LEVEL THERMAL
ADVECTION IS EXPECTED TO REMAIN OVER THE UPPER MISSISSIPPI
VALLEY...BUT THE SOUTH/SOUTHWESTERN MOST EXTENT OF THIS OMEGA MAY
CLIP OUR NORTH/NORTHEASTERN CWA AND AS A
RESULT...NORTH/NORTHEASTERN PORTIONS OF OUR CWA APPEAR MOST
FAVORED FOR PRECIPITATION THIS EVENING INTO TONIGHT. LOWER POPS
EXIST FARTHER SOUTHWEST ACROSS THE CWA WHERE BROAD-SCALE OMEGA
WILL BE WEAKER...BUT LOW LEVEL CONVERGENCE AND RESULTANT FORCING
ALONG THE LOW LEVEL BAROCLINIC ZONE MAY BE STRONG ENOUGH FOR
CONVECTIVE INITIATING AND RESULTANT PRECIPITATION PRODUCTION.
GIVEN ALL THIS...WENT AHEAD WITH 20% POPS ACROSS OUR FAR
WEST/NORTHWEST 21Z-00Z...WITH 20%-60% POPS SPREADING ACROSS MUCH
OF THE REST OF THE CWA 00Z-06Z. AGAIN...THE HIGHEST POPS HAVE BEEN
RELEGATED TO OUR NORTHEASTERN CWA. THE 15/12Z NAM SUGGESTS 0-1KM
MLCAPE VALUES OF ~1500J/KG WILL BE IN EXISTENCE ACROSS MUCH OF THE
CWA THIS AFTERNOON AND EVENING...WITH DEEP LAYER BULK SHEAR VALUES
OF 20-30KTS ALSO IN EXISTENCE. GIVEN THIS IT CERTAINLY APPEARS THE
GREATER RISK FOR SEVERE WEATHER THIS AFTERNOON AND EVENING WILL
EXIST FARTHER NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY WHERE
GREATER VALUES OF INSTABILITY WILL BE OBSERVED...BUT AN ISOLATED
REPORT OF LARGE HAIL CANNOT BE RULED OUT ACROSS OUR AREA WITH THE
AFOREMENTIONED INSTABILITY IN PLACE. IN ADDITION...SIMULATED
REFLECTIVITY FIELDS FROM THE 15/12Z 4KM WRF-NMM SUGGEST A
QLCS...ALBEIT DISORGANIZED...COULD BE REALIZED ALONG THE LOW LEVEL
BAROCLINIC ZONE FROM THE UPPER MISSISSIPPI VALLEY INTO PORTIONS OF
THE MISSOURI RIVER VALLEY...WITH THE VERY SOUTHWESTERN EXTENT OF
THIS SYSTEM PERHAPS CLIPPING OUR NORTHEASTERN CWA. GIVEN ALL
THIS...WILL GO AHEAD AND CONTINUE TO CARRY SEVERE STORM WORDING IN
THE HWO FOR LATE THIS AFTERNOON THROUGH THIS EVENING...WITH
NORTHEASTERN PORTIONS OF OUR CWA THE MOST LIKELY AREA TO OBSERVE
SEVERE WEATHER ACROSS OUR AREA.
ANY SEVERE WEATHER THAT IS REALIZED SHOULD BE SHORT-LIVED AS THE
LOW LEVEL BAROCLINIC ZONE QUICKLY PUSHES AWAY FROM THE AREA BY 06Z
AND THE MID LEVEL TROUGH AXIS PUSHES WELL TO THE EAST/NORTHEAST OF
OUR AREA. THE OVERALL LACK IN KINEMATIC FORCING WOULD OTHERWISE
PRESENT DRY CONDITIONS TO THE AREA HEADING INTO THE DAY
THURSDAY...BUT SHORT TERM GUIDANCE SUGGESTS THE ~50KT MID LEVEL
JET STREAK TO OUR NORTHWEST WILL PUSH OVERHEAD TOMORROW...WITH A
DIRECT THERMAL CIRCULATION WITHIN THE RIGHT-REAR QUAD OF THIS JET
STREAK PERHAPS PROVIDING ENOUGH LIFT FOR ADDITIONAL PRECIPITATION
PRODUCTION DURING THE MORNING HOUR THURSDAY. WENT AHEAD WITH 20%
POPS ACROSS THE ENTIRE CWA THURSDAY MORNING AS A RESULT.
LOW LEVEL PRESSURE RISES POST-FROPA WILL CREATE A SIGNIFICANT
INCREASE IN THE LOW LEVEL PRESSURE GRADIENT FOR A BRIEF TIME THIS
EVENING...LIKELY RESULTING IN STRONG WINDS ACROSS PORTIONS OF OUR
CWA PRIMARILY DURING THE 00Z-09Z TIME FRAME. MET AND MAV GUIDANCE
BOTH SUGGEST WIND SPEEDS FOR A FEW LOCATIONS ACROSS THE CWA COULD
FLIRT WITH WIND ADVISORY CRITERIA FOR A TIME...BUT THESE STRONGEST
WINDS ARE EXPECTED TO REMAIN FAIRLY BRIEF AND SHOULD NOT REQUIRE
ANY HEADLINES THIS EVENING OR TONIGHT.
BCCONSRAW HAS BECOME ONE OF THE BETTER SETS OF GUIDANCE WITH
RESPECT TO OVERNIGHT LOWS THE PAST FEW DAYS AND THUS PLAYED
CLOSELY TO BCCONSRAW FOR OVERNIGHT LOWS TONIGHT. OVERNIGHT LOWS IN
THE 60S ARE FORECAST ACROSS MUCH OF THE CWA FOR TONIGHT AS A
RESULT. A MAJOR COOL DOWN IS IN STORE FOR THE AREA BEGINNING
TOMORROW AS A MUCH COOLER AIRMASS SETTLES INTO THE REGION.
STATISTICALLY...CONSMOS AND ADJMAVBC HAVE BEEN DOING VERY WELL
WITH DAY 1 HIGH TEMPERATURES...BUT THE ADJMAVBC LOOKED A LITTLE
WARM WITH HIGHS IN THE UPPER 70S TO LOWER 80S. WITH STRONG LOW
LEVEL COLD AIR ADVECTION...AS WELL AS LINGERING CLOUD COVER AND
POSSIBLE PRECIPITATION...WOULD MUCH RATHER KEEP DAY TIME
TEMPERATURE RISES TO AROUND 15 DEGREES ON THURSDAY...WHICH WOULD
PRESENT THURSDAY HIGHS IN THE MID TO UPPER 70S FOR THE MOST PART.
CONSMOS SEEMED TO HAVE A BETTER HANDLE ON THIS AND THUS WENT
CONSMOS FOR HIGHS ON THURSDAY.
LONG TERM...BEGINNING 00Z FRIDAY AND CONTINUING THROUGH
WEDNESDAY. MAIN CONCERNS FOR THIS PERIOD WILL BE TEMPERATURES AND
PRECIPITATION. FOG MAY BECOME AN ISSUE FRIDAY MORNING AS WELL.
STARTING WITH FRIDAY MORNING...LOW TEMPERATURES WILL BE THE
COOLEST LOWS OBSERVED THROUGHOUT THE LONG TERM AS TEMPERATURES
WILL BE 10 TO 15 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. A
STEADY INCREASE IN LOW TEMPERATURES EACH DAY WILL BE OBSERVED
THROUGH THE EXTENDED FORECAST...EVENTUALLY GETTING BACK TO NEAR
NORMAL LOW TEMPERATURES ON MONDAY. WENT WITH BCCONSRAW FOR FRIDAY
LOW TEMPS AND BCCONSALL FOR LOW TEMPS ON SATURDAY...BOTH CHANGES
INDUCED A SLIGHT LOWERING IN LOW TEMPERATURES FROM THE PREVIOUS
FORECAST. HIGH TEMPERATURES DURING THIS PERIOD WILL BEGIN BELOW
NORMAL AS WELL...WITH TEMPERATURES EVENTUALLY GETTING BACK TO
NORMAL ON MONDAY. WENT WITH THE PREVIOUS SHIFTS HIGH TEMPERATURES
FOR FRIDAY AND SATURDAY. ALLBLEND TOOK CARE OF THE FOLLOWING DAYS
WITH VERY REASONABLE OUTCOMES FOR BOTH LOW AND HIGH TEMPERATURES.
PRECIPITATION CHANCES WILL BEGIN AS EARLY AS FRIDAY EVENING AND
CONTINUE ON INTO SUNDAY MORNING AS A WEAK WAVE MOVES THROUGH THE
PLAINS. INITIALIZATION OF THE PRECIPITATION ACROSS SOUTHWESTERN
PARTS OF THE CWA FRIDAY EVENING ARE IN PRETTY GOOD AGREEMENT WITH
THE NAM12...GFS40...AND THE EC. SREF 6-HR QPF PROBABILITIES FOR
GREATER THAN 0.01 INCHES OF PRECIPITATION AT 00Z SATURDAY INDICATE
NEAR 50 PERCENT FOR NEARLY THE ENTIRE SOUTHWESTERN HALF OF THE
CWA. A LESS CLEAR PICTURE IS PAINTED AS DISAGREEMENT BETWEEN MODEL
OUTPUT WITH PRECIPITATION COVERAGE BECOMES EVIDENT LATER IN THE
DAY. LEANED MORE TOWARDS THE NAM SOLUTION FOR SATURDAY AND
ALLBLEND FOR SUNDAY MORNING. DEEP LAYER SHEAR AND SURFACE BASED
CAPE ARE WEAK...BUT LOW LEVEL SHEAR IS MODEST...WITH EARLY
AFTERNOON VALUES BETWEEN 15 AND 25 KTS/KM. THUNDERSTORMS ARE
POSSIBLE BUT SEVERE POTENTIAL IS VERY LIMITED AT THE MOMENT. THE
NEXT CHANCE FOR PRECIPITATION IS MONDAY EVENING LEADING INTO
TUESDAY MORNING...AND HAS BEEN THE CASE FOR PREVIOUS FORECAST
ACROSS THE CWA. THE GFS AND EC ARE IN PRETTY GOOD AGREEMENT FOR
PRECIPITATION ON TUESDAY MORNING. THUNDERSTORMS WILL BE POSSIBLE
WITH THIS SYSTEM ON TUESDAY.
SURFACE DEW POINT DEPRESSIONS WILL BE CLOSE TO 5 DEGREES OR LESS
FOR NORTHERN AND WESTERN PARTS OF THE CWA FRIDAY MORNING. MAY WANT
TO CONSIDER MONITORING FOG CONDITIONS TOMORROW EVENING AS THE
PICTURE BECOMES MORE CLEAR. MODELS ARE INDICATING A SURFACE HIGH
SITTING OVER THE NORTHERN/CENTRAL PLAINS...LIGHT WINDS ACROSS MUCH
OF THE OUTLOOK AREA FRIDAY MORNING...AND MOSTLY CLEAR SKIES WILL
HELP INDUCE FOG UNDER THESE CONDITIONS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
237 PM CDT TUE AUG 14 2012
.DISCUSSION...
88D MOSAIC LOOP THIS AFTERNOON SHOWING SMALL AREA OF ELEVATED
CONVECTION SLOWLY MOVING ACROSS THE NRN CWA. A FEW STATIONS HAVE
HAD HOURLY PCPN AROUND A TENTH OR SO. EXPECT THOUGH ACTIVITY WILL
WEAKEN AS IT PROGRESSES EASTWARD INTO AREA OF HIGHER CINH.
FOR TONIGHT...NAM/GFS/ECM ALL PLACING SMALL AREA OF QPF IN THE
VICINITY OF THE NRN CWA ASSOCIATED WITH WAA FORCING LIFTING NORTH
INTO THE DAKOTAS/UPPER MIDWEST. HOWEVER...12Z RUN OF 4KM WRF IS DRY
AS WELL AS RAP GUIDANCE.
OTHERWISE...LARGE SCALE FLOW CONSISTING OF A DEEP BROAD TROF
ESTABLISHED OVER THE EASTERN CONUS WITH UPSTREAM NORTHWEST FLOW
EXTENDING ALL THE WAY TO THE BRITISH COLUMBIA COASTLINE. PATTERN
THOUGH WILL GRADUALLY ALTER LATER THIS WEEK WHEN DEEP LOW PRESSURE
OVER THE ALASKAN GULF SHIFT EAST AND PUSHES AN AMPLIFYING RIDGE
TOWARD THE ROCKIES.
IN THE MEANTIME...SHORT TERM FEATURE OF INTEREST CONTINUES TO BE
ANTICIPATED COLD FRONT PUSHING DEEP INTO PLAINS ON WEDNESDAY. LEADING
EDGE OF COLD FRONT SHOULD BE PUSHING INTO THE NRN CWA BY AFTERNOON
AND QUICKLY SLIDE SEWD THROUGH THURSDAY MORNING. SVR STORM THREAT AS
THE BNDRY PUSHES THRU QUITE POSSIBLE IF NOT LIKELY WHEN CAP WEAKENS
BY LATE AFTN. INSTABILITY AND SHEAR WILL BE ABUNDANT...MUCAPE 3500
J/KG...LI -7...EFFECTIVE SHEAR 30-40KT...TO PRODUCE STORMS
CONTAINING LARGE HAIL AND DAMAGING WINDS. EXPECT LINGERING PCPN
ACTIVITY THURSDAY MORNING...FOR THE MOST PART SOUTH OF I-80...SHOULD
COME TO A CLOSE BEFORE AFTN. THIS FRONT WILL BRING A NOTICEABLE
CHANCE IN TEMPS...COMPARED TO AS OF LATE...WITH HIGHS THURSDAY THRU
SUNDAY IN THE MID/UPPER 70S.
FOR MONDAY AND TUESDAY...EXPECT A SLIGHT WARMING TREND OVER THE
CNTRL PLAINS AS AFOREMENTIONED UPPER RIDGE SLIDES CLOSER TO THE
REGION. SHOULD BE ABLE TO REACH LOW/MID 80S FOR AFTN HIGHS.
DEE
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ASSOCIATED WITH A
WEAK UPPER LEVEL IMPULSE...ALONG AND AND NORTH A WEAK MID LEVEL
FRONTAL BOUNDARY WILL CONTINUE TO MOVE THROUGH NORTHEAST
NEBRASKA...AFFECTING THE KOFK TAF SITE THROUGH ABOUT 20Z.
OTHERWISE...VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD WITH
SOUTH SOUTHWESTERLY WINDS AROUND 12 KNOTS. COULD BE SOME SPORADIC
GUSTS UP TO ABOUT 18 KNOTS. GUSTS COULD REDEVELOP BY 15/15Z
TOMORROW AS WELL AHEAD OF THE NEXT COLD FRONT.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1219 PM CDT TUE AUG 14 2012
.AVIATION...18Z TAFS FOR KOFK...KOMA AND KLNK.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ASSOCIATED WITH A
WEAK UPPER LEVEL IMPULSE...ALONG AND AND NORTH A WEAK MID LEVEL
FRONTAL BOUNDARY WILL CONTINUE TO MOVE THROUGH NORTHEAST
NEBRASKA...AFFECTING THE KOFK TAF SITE THROUGH ABOUT 20Z.
OTHERWISE...VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD WITH
SOUTH SOUTHWESTERLY WINDS AROUND 12 KNOTS. COULD BE SOME SPORADIC
GUSTS UP TO ABOUT 18 KNOTS. GUSTS COULD REDEVELOP BY 15/15Z
TOMORROW AS WELL AHEAD OF THE NEXT COLD FRONT.
DEWALD
&&
.PREV DISCUSSION... /ISSUED 351 AM CDT TUE AUG 14 2012/
DISCUSSION...
FORECAST CONCERNS EARLY ON WILL BE ANY LINGERING PRECIPITATION AND
CLOUDS TODAY...THEN PRECIPITATION CHANCES TONIGHT AND BETTER
CHANCES FOR RAIN WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING.
THE 00Z H5 PATTERN HAD THE CENTRAL PLAINS UNDER NORTHWEST FLOW ALOFT
WITH A COUPLE OF EMBEDDED SHORTWAVES. AT 04Z...THE SHORTWAVE OVER
MONTANA HAD ALREADY PUSHED INTO THE DAKOTAS...AND THE SHORTWAVE OVER
COLORADO WAS ADVANCING INTO WRN KANSAS. THE 00Z 80KT H3 JET WAS OVER
NEBRASKA AND THERE WAS SOME DECENT UPR LEVEL DIVERGENCE OVER
COLORADO. THE H85 THETA-E AXIS AXIS AT 06Z WAS OVER THE WESTERN
PLAINS WITH H85 WINDS PER THE VWPS FM THE SOUTH AT AROUND 30 TO
35KTS. STEEP MID LEVEL LAPSE RATES OF 7 TO 8.5 DEG C/KM WERE ALSO IN
THIS REGION. BY 08Z...THE LAST WSR-88D RADAR MOSAIC HAD SOME
SHOWERS AND THUNDERSTORMS FROM THE CNTRL DAKOTAS BACK TOWARD WRN
NEBRASKA...A FEW ECHOES IN CENTRAL AND EASTERN NEBRASKA THAT HAD
WEAKENED FROM EARLIER THIS AM...AND A MORE ORGANIZED AREA OF
PRECIPITATION OVER KANSAS. AN EARLIER RUN OF THE HRRR DID NOT
PICK UP ON THE TSRA FOR CENTRAL NEBRASKA AND THE LATEST RUN IS
DOING A BETTER JOB...WITH A CONTINUED WEAKENING TREND AS THE
STORMS MOVE EAST.
THIS MORNING...THE LOW LEVEL JET IS PROGGED TO CONTINUE FROM 30 TO
35KTS FROM THE WCNTRL DAKOTAS INTO CNTRL NEBRASKA...SOUTH INTO
WRN AND CNTRL KANSAS WITH SOME VEERING DURING THE MORNING. THE
TRENDS ON THE IR SATELLITE WEAKENING AND THE NORTHERN WAVE REMAINS
WEAK AS IT MOVES THRU THE PLAINS WITH OTHER WEAK PIECES OF ENERGY
IN THE NORTHWEST FLOW ALOFT. THE SOUTHERN SHORTWAVE TROF IS
STRONGER AND MAINTAINS IT`S STRENGTH ACROSS KANSAS. SHOULD SEE
SOME CONVECTIVE DEBRIS WITH THESE SYSTEMS THIS MORNING. ALTHOUGH
DYNAMICS ARE WEAK...THETA-E ADVECTION CONTINUES DURING THE MORNING
AND EARLY AFTERNOON ALONG WITH MID LEVEL MOISTURE. WILL MENTION
ISOLATED SHOWERS ACROSS PARTS OF THE SOUTH THIS MORNING WITH A FEW
SPRINKLES FARTHER NORTH...AND COULD SEE AND ISOLATED SHOWER IN THE
NORTH THIS AFTERNOON AND EVENING. WITH THE VARIABLE
CLOUDS...TEMPERATURES COULD BE HELD DOWN...BUT FOR NOW HAVE HIGHS
IN THE MID TO UPPER 80S.
A MUCH STRONGER FRONT WILL MOVE INTO THE FORECAST AREA WEDNESDAY
AFTERNOON. THE LOW LEVEL JET STRENGTHENS TONIGHT AND CONTINUES
INTO WED NIGHT. INSTABILITY AND SHEAR INCREASE WITH THE
APPROACHING FRONT ALONG WITH DEEPER MOISTURE RETURN.
FRONTOGENESIS...UVV...AND STEEP LAPSE RATES ALL SUPPORT THE CHC
FOR SCT THUNDERSTORMS. HAVE MAINTAINED HIGH CHC POPS FOR MOST OF
THE AREA TO LIKELY POPS FOR THE NORTHEAST...WITH INCREASING CHANCE
FOR STORMS WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT...LINGERING
INTO THURSDAY MORNING. HIGHS WEDNESDAY SHOULD TOP OUT IN THE 90S.
SURFACE HIGH PRESSURE WILL BUILD IN LATER THURSDAY AND FRIDAY WITH
COOLER HIGH TEMPERATURES IN THE 70S AND LOWS IN THE 40S AND 50S.
THE FORECAST INTO THE WEEKEND REMAINS COOL WITH HIGHS IN THE 70S
AND LOWER 80S. THERE COULD BE SOME STORMS SATURDAY WITH A WEAK
FRONTAL PASSAGE.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
632 AM CDT TUE AUG 14 2012
.AVIATION...
12Z TAFS FOR KOMA...KLNK...KOFK.
EXPECT VFR CONDITIONS THROUGH THE NEXT 24 HOURS. VARIABLE AMOUNTS
OF CLOUDINESS WILL OCCUR...WITH ANY CEILINGS FORECAST TO BE AT OR
ABOVE 9000 FEET. ALTHOUGH SOME ISOLATED -TSRA MAY OCCUR...FELT THE
CHANCE WAS LOW ENOUGH TO LEAVE OUT OF TAFS FOR NOW. SOUTHERLY
WINDS SHOULD INCREASE INTO THE 11-15 KNOT RANGE TODAY...THEN BE
IN THE 7-11 KNOT RANGE TONIGHT.
MILLER
&&
.PREV DISCUSSION... /ISSUED 351 AM CDT TUE AUG 14 2012/
DISCUSSION...
FORECAST CONCERNS EARLY ON WILL BE ANY LINGERING PRECIPITATION AND
CLOUDS TODAY...THEN PRECIPITATION CHANCES TONIGHT AND BETTER
CHANCES FOR RAIN WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING.
THE 00Z H5 PATTERN HAD THE CENTRAL PLAINS UNDER NORTHWEST FLOW ALOFT
WITH A COUPLE OF EMBEDDED SHORTWAVES. AT 04Z...THE SHORTWAVE OVER
MONTANA HAD ALREADY PUSHED INTO THE DAKOTAS...AND THE SHORTWAVE OVER
COLORADO WAS ADVANCING INTO WRN KANSAS. THE 00Z 80KT H3 JET WAS OVER
NEBRASKA AND THERE WAS SOME DECENT UPR LEVEL DIVERGENCE OVER
COLORADO. THE H85 THETA-E AXIS AXIS AT 06Z WAS OVER THE WESTERN
PLAINS WITH H85 WINDS PER THE VWPS FM THE SOUTH AT AROUND 30 TO
35KTS. STEEP MID LEVEL LAPSE RATES OF 7 TO 8.5 DEG C/KM WERE ALSO IN
THIS REGION. BY 08Z...THE LAST WSR-88D RADAR MOSAIC HAD SOME
SHOWERS AND THUNDERSTORMS FROM THE CNTRL DAKOTAS BACK TOWARD WRN
NEBRASKA...A FEW ECHOES IN CENTRAL AND EASTERN NEBRASKA THAT HAD
WEAKENED FROM EARLIER THIS AM...AND A MORE ORGANIZED AREA OF
PRECIPITATION OVER KANSAS. AN EARLIER RUN OF THE HRRR DID NOT
PICK UP ON THE TSRA FOR CENTRAL NEBRASKA AND THE LATEST RUN IS
DOING A BETTER JOB...WITH A CONTINUED WEAKENING TREND AS THE
STORMS MOVE EAST.
THIS MORNING...THE LOW LEVEL JET IS PROGGED TO CONTINUE FROM 30 TO
35KTS FROM THE WCNTRL DAKOTAS INTO CNTRL NEBRASKA...SOUTH INTO
WRN AND CNTRL KANSAS WITH SOME VEERING DURING THE MORNING. THE
TRENDS ON THE IR SATELLITE WEAKENING AND THE NORTHERN WAVE REMAINS
WEAK AS IT MOVES THRU THE PLAINS WITH OTHER WEAK PIECES OF ENERGY
IN THE NORTHWEST FLOW ALOFT. THE SOUTHERN SHORTWAVE TROF IS
STRONGER AND MAINTAINS IT`S STRENGTH ACROSS KANSAS. SHOULD SEE
SOME CONVECTIVE DEBRIS WITH THESE SYSTEMS THIS MORNING. ALTHOUGH
DYNAMICS ARE WEAK...THETA-E ADVECTION CONTINUES DURING THE MORNING
AND EARLY AFTERNOON ALONG WITH MID LEVEL MOISTURE. WILL MENTION
ISOLATED SHOWERS ACROSS PARTS OF THE SOUTH THIS MORNING WITH A FEW
SPRINKLES FARTHER NORTH...AND COULD SEE AND ISOLATED SHOWER IN THE
NORTH THIS AFTERNOON AND EVENING. WITH THE VARIABLE
CLOUDS...TEMPERATURES COULD BE HELD DOWN...BUT FOR NOW HAVE HIGHS
IN THE MID TO UPPER 80S.
A MUCH STRONGER FRONT WILL MOVE INTO THE FORECAST AREA WEDNESDAY
AFTERNOON. THE LOW LEVEL JET STRENGTHENS TONIGHT AND CONTINUES
INTO WED NIGHT. INSTABILITY AND SHEAR INCREASE WITH THE
APPROACHING FRONT ALONG WITH DEEPER MOISTURE RETURN.
FRONTOGENESIS...UVV...AND STEEP LAPSE RATES ALL SUPPORT THE CHC
FOR SCT THUNDERSTORMS. HAVE MAINTAINED HIGH CHC POPS FOR MOST OF
THE AREA TO LIKELY POPS FOR THE NORTHEAST...WITH INCREASING CHANCE
FOR STORMS WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT...LINGERING
INTO THURSDAY MORNING. HIGHS WEDNESDAY SHOULD TOP OUT IN THE 90S.
SURFACE HIGH PRESSURE WILL BUILD IN LATER THURSDAY AND FRIDAY WITH
COOLER HIGH TEMPERATURES IN THE 70S AND LOWS IN THE 40S AND 50S.
THE FORECAST INTO THE WEEKEND REMAINS COOL WITH HIGHS IN THE 70S
AND LOWER 80S. THERE COULD BE SOME STORMS SATURDAY WITH A WEAK
FRONTAL PASSAGE.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
351 AM CDT TUE AUG 14 2012
.DISCUSSION...
FORECAST CONCERNS EARLY ON WILL BE ANY LINGERING PRECIPITATION AND
CLOUDS TODAY...THEN PRECIPITATION CHANCES TONIGHT AND BETTER
CHANCES FOR RAIN WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING.
THE 00Z H5 PATTERN HAD THE CENTRAL PLAINS UNDER NORTHWEST FLOW ALOFT
WITH A COUPLE OF EMBEDDED SHORTWAVES. AT 04Z...THE SHORTWAVE OVER
MONTANA HAD ALREADY PUSHED INTO THE DAKOTAS...AND THE SHORTWAVE OVER
COLORADO WAS ADVANCING INTO WRN KANSAS. THE 00Z 80KT H3 JET WAS OVER
NEBRASKA AND THERE WAS SOME DECENT UPR LEVEL DIVERGENCE OVER
COLORADO. THE H85 THETA-E AXIS AXIS AT 06Z WAS OVER THE WESTERN
PLAINS WITH H85 WINDS PER THE VWPS FM THE SOUTH AT AROUND 30 TO
35KTS. STEEP MID LEVEL LAPSE RATES OF 7 TO 8.5 DEG C/KM WERE ALSO IN
THIS REGION. BY 08Z...THE LAST WSR-88D RADAR MOSAIC HAD SOME
SHOWERS AND THUNDERSTORMS FROM THE CNTRL DAKOTAS BACK TOWARD WRN
NEBRASKA...A FEW ECHOES IN CENTRAL AND EASTERN NEBRASKA THAT HAD
WEAKENED FROM EARLIER THIS AM...AND A MORE ORGANIZED AREA OF
PRECIPITATION OVER KANSAS. AN EARLIER RUN OF THE HRRR DID NOT
PICK UP ON THE TSRA FOR CENTRAL NEBRASKA AND THE LATEST RUN IS
DOING A BETTER JOB...WITH A CONTINUED WEAKENING TREND AS THE
STORMS MOVE EAST.
THIS MORNING...THE LOW LEVEL JET IS PROGGED TO CONTINUE FROM 30 TO
35KTS FROM THE WCNTRL DAKOTAS INTO CNTRL NEBRASKA...SOUTH INTO
WRN AND CNTRL KANSAS WITH SOME VEERING DURING THE MORNING. THE
TRENDS ON THE IR SATELLITE WEAKENING AND THE NORTHERN WAVE REMAINS
WEAK AS IT MOVES THRU THE PLAINS WITH OTHER WEAK PIECES OF ENERGY
IN THE NORTHWEST FLOW ALOFT. THE SOUTHERN SHORTWAVE TROF IS
STRONGER AND MAINTAINS IT`S STRENGTH ACROSS KANSAS. SHOULD SEE
SOME CONVECTIVE DEBRIS WITH THESE SYSTEMS THIS MORNING. ALTHOUGH
DYNAMICS ARE WEAK...THETA-E ADVECTION CONTINUES DURING THE MORNING
AND EARLY AFTERNOON ALONG WITH MID LEVEL MOISTURE. WILL MENTION
ISOLATED SHOWERS ACROSS PARTS OF THE SOUTH THIS MORNING WITH A FEW
SPRINKLES FARTHER NORTH...AND COULD SEE AND ISOLATED SHOWER IN THE
NORTH THIS AFTERNOON AND EVENING. WITH THE VARIABLE
CLOUDS...TEMPERATURES COULD BE HELD DOWN...BUT FOR NOW HAVE HIGHS
IN THE MID TO UPPER 80S.
A MUCH STRONGER FRONT WILL MOVE INTO THE FORECAST AREA WEDNESDAY
AFTERNOON. THE LOW LEVEL JET STRENGTHENS TONIGHT AND CONTINUES
INTO WED NIGHT. INSTABILITY AND SHEAR INCREASE WITH THE
APPROACHING FRONT ALONG WITH DEEPER MOISTURE RETURN.
FRONTOGENESIS...UVV...AND STEEP LAPSE RATES ALL SUPPORT THE CHC
FOR SCT THUNDERSTORMS. HAVE MAINTAINED HIGH CHC POPS FOR MOST OF
THE AREA TO LIKELY POPS FOR THE NORTHEAST...WITH INCREASING CHANCE
FOR STORMS WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT...LINGERING
INTO THURSDAY MORNING. HIGHS WEDNESDAY SHOULD TOP OUT IN THE 90S.
SURFACE HIGH PRESSURE WILL BUILD IN LATER THURSDAY AND FRIDAY WITH
COOLER HIGH TEMPERATURES IN THE 70S AND LOWS IN THE 40S AND 50S.
THE FORECAST INTO THE WEEKEND REMAINS COOL WITH HIGHS IN THE 70S
AND LOWER 80S. THERE COULD BE SOME STORMS SATURDAY WITH A WEAK
FRONTAL PASSAGE.
&&
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
HAVE CONTINUED TAF FORECASTS FOR VFR CONDITIONS...THE HIGHEST
PROBABILITY OCCURRENCE...BUT THERE REMAINS A LOW
PROBABILITY/CONFIDENCE ISSUE REGARDING FOG. SOME PATCHY FOG
IS POSSIBLE OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA WITH
SATURATION ALREADY REPORTED AT KICL AT 04Z. HOWEVER WITH
INCREASING MID CLOUD CIGS EXPECTED TO SPREAD INTO THE AREA AND
GROUND SURFACE QUITE DRY FROM LACK OF RAIN HAVE KEPT FOG OUT AT
TAF SITES. UPSTREAM CONVECTION OVER WRN SOUTH DAKOTA EXPECTED TO
STAY WEST OF TAF SITES BASED ON EVENING MODEL RUN.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
942 PM MDT WED AUG 15 2012
.UPDATE...
QUICK ZFP UPDATE TO MODIFY WINDS MAINLY IN THE NORTHEAST/NORTH
CENTRAL AREAS FOR THE INCOMING FRONTAL BOUNDARY. NAM12/RUC13
CONTINUE TO INDICATE A FASTER/STRONGER PUSH LATER TONIGHT AND
THURSDAY MORNING...AS WELL AS SUGGESTING A NORTHEAST TO EAST WIND
INTO PORTIONS OF THE UPPER/MIDDLE RGV THURSDAY MORNING.
OTHERWISE...NO CHANGES.
&&
.AVIATION...
00Z TAF CYCLE
VFR CONDITIONS WILL PREVAIL OVER MOST OF THE FORECAST AREA OF
NORTHERN AND CENTRAL NM THROUGH THE NEXT 24 HOURS. THE EXCEPTION
WILL BE FROM ISOLATED STORMS PRODUCING BRIEF DOWNPOURS AND LOCALIZED
MVFR CONDITIONS. GUSTY AND ERRATIC WINDS WILL ALSO ACCOMPANY
THUNDERSTORMS AS WILL SOME SMALL HAIL. AREAS FAVORED FOR STORM
DEVELOPMENT THROUGH 16/0600UTC WILL BE IN THE EASTERN PLAINS
...ALONG THE CENTRAL MOUNTAIN CHAIN...AND OVER PARTS OF THE
SOUTHWESTERN MOUNTAINS OF NM. MOST STORMS WILL WANE BEFORE
MIDNIGHT...AND A BACK DOOR COLD FRONT WILL BEGIN INFILTRATING THE
STATE FROM THE NORTHEAST BEFORE DAWN THURSDAY. THIS FRONT WILL
ADVANCE FARTHER SOUTH AND WEST TOWARD THE CENTRAL MOUNTAIN CHAIN BY
THURSDAY AFTERNOON...INCREASING POTENTIAL FOR STORMS.
52
&&
.PREV DISCUSSION...300 PM MDT WED AUG 15 2012...
NO SIGNIFICANT CHANGES MADE FROM PREVIOUS FORECAST. CIRA BLENDED TPW
IMAGERY SHOWS THE BEST MOISTURE AXIS ACROSS CENTRAL AND EASTERN AZ...
WHILE AN AREA OF DRIER AIR HAS WORKED SLOWLY SOUTHWARD INTO THE FAR
NORTHERN REGION OF NM. 20Z LAPS INSTABILITY CONSISTENT WITH LATEST
RADAR TRENDS WHERE MAJORITY OF ACTIVITY NEAR AND SE OF THE CENTRAL MT
CHAIN. HRRR GUIDANCE PERFORMED WELL ON TUESDAY AND CAPTURES CURRENT
CONDITIONS SO HAVE NUDGED POPS TOWARD ITS SOLUTION FOR THIS EVENING.
EXPECT NW STEERING FLOW TO PUSH ACTIVITY INTO THE PLAINS WHILE CENTRAL
AND WESTERN NM ACTS ON OUTFLOW BOUNDARIES FOR STORMS.
THE MUCH ANTICIPATED BACK DOOR FRONTAL BOUNDARY IS GATHERING STRENGTH
OVER NE COLORADO. 20Z SURFACE OBS AND MODEL FRONTOGENESIS SUPPORTS A
RATHER STRONG BOUNDARY PUSHING SOUTH INTO NE NM THRU TONIGHT...WITH
BREEZY CONDITIONS IN ITS WAKE. THIS FRONT WILL ACT AS A STRONG FOCUS
FOR SHOWERS AND STORMS THURSDAY ALONG AND EAST OF THE CENTRAL MT
CHAIN. NW FLOW ALOFT BENEATH THE RIDGE CENTERED OVER E AZ WILL COMBINE
WITH LOW LEVEL UPSLOPE FLOW TO PRODUCE SCT TO NMRS COVERAGE DURING THE
AFTERNOON THEN A POTENTIAL COMPLEX THURSDAY EVENING OVER THE PLAINS.
GAP WINDS INTO THE RIO GRANDE VALLEY MAY BE ENHANCED BY CONVECTION
DEPENDING ON WHERE STORMS FIRE. SE STEERING FLOW UP TO 650MB INTO THE
RIO GRANDE VALLEY WILL ALLOW SOME STORMS TO MAKE IT INTO THE AREA FROM
THE SANDIA/MANZANO MTS. RAISED POPS ANOTHER FEW POINTS.
THE OVERALL PATTERN WILL BE PERSISTENT THRU THE WEEKEND WITH NW FLOW
ALOFT AND LOW LEVEL MOIST SOUTH TO SOUTHEASTERLY FLOW. THIS WILL
MAKE FOR WHAT WILL LIKELY BE THE BEST EXTENDED PERIOD OF DECENT
PRECIP CHANCES ACROSS THE E PLAINS IN QUITE SOME TIME. HAVE CONTINUED
WITH POPS JUST BELOW LIKELY CATEGORY FOR THE EAST WHERE CONVECTION
DEVELOPING OVER THE HIGH TERRAIN WILL ORGANIZE INTO AREAS OF STORMS
AND RAIN EACH EVENING. TEMPS WILL BE BELOW NORMAL AS WELL OUT EAST
WHICH WILL BE QUITE A CHANGE FROM THE PAST COUPLE MONTHS. THE GFS IS
ALSO SHOWING SOME OF THE MONSOON MOISTURE CURRENTLY OVER NORTHERN
MEXICO SEEPING NORTH INTO THE SW MTS...ENHANCING ACTIVITY OVER THAT
REGION AS WELL. WAS A LITTLE CONSERVATIVE WITH POPS IN THAT AREA BUT
THIS NEEDS TO BE WATCHED AS LOW LEVEL MOISTURE CAN SURGE NORTH VERY
QUICKLY FROM JUST ONE STRONG CONVECTIVE COMPLEX TO THE SOUTH AT ANY
TIME.
GUIDANCE BEYOND THE WEEKEND CONTINUES TO WAFFLE BACK AND FORTH WHERE
THE HIGH CENTER WILL BE SO CONFIDENCE QUITE LOW FOR NEXT WEEK. GUYER
&&
.FIRE WEATHER...
THE UPPER HIGH IS FORECAST TO CONTINUE AS THE DOMINANT WEATHER
FEATURE THROUGH THE NEXT SEVEN DAYS...ALTHOUGH TWO BACKDOOR FRONTAL
SURGES WILL ADD MOISTURE TO THE EQUATION.
A WEAK COLD FRONT WILL PUSH SOUTHWEST ACROSS THE STATE THURSDAY...
PUSHING LOW LAYER MOISTURE WEST TO THE CONTINENTAL DIVIDE AND
RESULTING IN AN UPTICK IN WETTING SHOWERS AND THUNDERSTORMS. BREEZY
EAST CANYON WINDS ARE FORECAST TO ACCOMPANY THE FRONTAL PASSAGE
THROUGH THE CENTRAL MOUNTAIN CHAIN LATE THURSDAY. RELATIVE HUMIDITIES
WILL TREND UP BEHIND THE FRONT AND TEMPERATURES WILL TREND DOWN
SLIGHTLY THROUGH FRIDAY...ESPECIALLY ALONG/EAST OF THE CENTRAL
MOUNTAIN CHAIN WHERE THE BEST CHANCES FOR WETTING RAIN WILL RESIDE.
ANOTHER WEAK FRONTAL PUSH WILL COME DOWN THE PLAINS SATURDAY
NIGHT...KEEPING GOOD CHANCES FOR WETTING RAINS GOING THROUGH THE
WEEKEND WITH THE BEST CHANCES ALONG/EAST OF THE CENTRAL MOUNTAIN
CHAIN AROUND THE PERIPHERY OF THE UPPER HIGH. OVERNIGHT HUMIDITY
RECOVERIES WILL BE GOOD TO EXCELLENT THROUGH THE WEEKEND THANKS TO
THE ADDED POST-FRONTAL MOISTURE.
RECYCLE MODE IS FORECAST EARLY NEXT WEEK WITH ABOVE NORMAL
TEMPERATURES. LOWER CONFIDENCE FORECAST GOING INTO MID WEEK WITH
DIFFERENCES AMONG THE 12Z MEDIUM RANGE MODEL SOLUTIONS IN THE
PLACEMENT OF THE UPPER HIGH. THE 12Z GFS SHUTS-DOWN THE EAST AND
FAVORS THE WEST AND NORTH FOR WETTING RAINS WITH THE UPPER HIGH
CENTERED OVER FAR WEST TEXAS BY LATE NEXT WEDNESDAY. A TREND BACK
TOWARD LOWER CHANCES FOR WETTING RAINS AND ABOVE NORMAL TEMPERATURE
WOULD FIT THE RECENT PATTERN AND IS THE MOST LIKELY SOLUTION. 11
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
546 PM MDT WED AUG 15 2012
.AVIATION...
00Z TAF CYCLE
VFR CONDITIONS WILL PREVAIL OVER MOST OF THE FORECAST AREA OF
NORTHERN AND CENTRAL NM THROUGH THE NEXT 24 HOURS. THE EXCEPTION
WILL BE FROM ISOLATED STORMS PRODUCING BRIEF DOWNPOURS AND LOCALIZED
MVFR CONDITIONS. GUSTY AND ERRATIC WINDS WILL ALSO ACCOMPANY
THUNDERSTORMS AS WILL SOME SMALL HAIL. AREAS FAVORED FOR STORM
DEVELOPMENT THROUGH 16/0600UTC WILL BE IN THE EASTERN PLAINS
...ALONG THE CENTRAL MOUNTAIN CHAIN...AND OVER PARTS OF THE
SOUTHWESTERN MOUNTAINS OF NM. MOST STORMS WILL WANE BEFORE
MIDNIGHT...AND A BACK DOOR COLD FRONT WILL BEGIN INFILTRATING THE
STATE FROM THE NORTHEAST BEFORE DAWN THURSDAY. THIS FRONT WILL
ADVANCE FARTHER SOUTH AND WEST TOWARD THE CENTRAL MOUNTAIN CHAIN BY
THURSDAY AFTERNOON...INCREASING POTENTIAL FOR STORMS.
52
&&
.PREV DISCUSSION...300 PM MDT WED AUG 15 2012...
NO SIGNIFICANT CHANGES MADE FROM PREVIOUS FORECAST. CIRA BLENDED TPW
IMAGERY SHOWS THE BEST MOISTURE AXIS ACROSS CENTRAL AND EASTERN AZ...
WHILE AN AREA OF DRIER AIR HAS WORKED SLOWLY SOUTHWARD INTO THE FAR
NORTHERN REGION OF NM. 20Z LAPS INSTABILITY CONSISTENT WITH LATEST
RADAR TRENDS WHERE MAJORITY OF ACTIVITY NEAR AND SE OF THE CENTRAL MT
CHAIN. HRRR GUIDANCE PERFORMED WELL ON TUESDAY AND CAPTURES CURRENT
CONDITIONS SO HAVE NUDGED POPS TOWARD ITS SOLUTION FOR THIS EVENING.
EXPECT NW STEERING FLOW TO PUSH ACTIVITY INTO THE PLAINS WHILE CENTRAL
AND WESTERN NM ACTS ON OUTFLOW BOUNDARIES FOR STORMS.
THE MUCH ANTICIPATED BACK DOOR FRONTAL BOUNDARY IS GATHERING STRENGTH
OVER NE COLORADO. 20Z SURFACE OBS AND MODEL FRONTOGENESIS SUPPORTS A
RATHER STRONG BOUNDARY PUSHING SOUTH INTO NE NM THRU TONIGHT...WITH
BREEZY CONDITIONS IN ITS WAKE. THIS FRONT WILL ACT AS A STRONG FOCUS
FOR SHOWERS AND STORMS THURSDAY ALONG AND EAST OF THE CENTRAL MT
CHAIN. NW FLOW ALOFT BENEATH THE RIDGE CENTERED OVER E AZ WILL COMBINE
WITH LOW LEVEL UPSLOPE FLOW TO PRODUCE SCT TO NMRS COVERAGE DURING THE
AFTERNOON THEN A POTENTIAL COMPLEX THURSDAY EVENING OVER THE PLAINS.
GAP WINDS INTO THE RIO GRANDE VALLEY MAY BE ENHANCED BY CONVECTION
DEPENDING ON WHERE STORMS FIRE. SE STEERING FLOW UP TO 650MB INTO THE
RIO GRANDE VALLEY WILL ALLOW SOME STORMS TO MAKE IT INTO THE AREA FROM
THE SANDIA/MANZANO MTS. RAISED POPS ANOTHER FEW POINTS.
THE OVERALL PATTERN WILL BE PERSISTENT THRU THE WEEKEND WITH NW FLOW
ALOFT AND LOW LEVEL MOIST SOUTH TO SOUTHEASTERLY FLOW. THIS WILL
MAKE FOR WHAT WILL LIKELY BE THE BEST EXTENDED PERIOD OF DECENT
PRECIP CHANCES ACROSS THE E PLAINS IN QUITE SOME TIME. HAVE CONTINUED
WITH POPS JUST BELOW LIKELY CATEGORY FOR THE EAST WHERE CONVECTION
DEVELOPING OVER THE HIGH TERRAIN WILL ORGANIZE INTO AREAS OF STORMS
AND RAIN EACH EVENING. TEMPS WILL BE BELOW NORMAL AS WELL OUT EAST
WHICH WILL BE QUITE A CHANGE FROM THE PAST COUPLE MONTHS. THE GFS IS
ALSO SHOWING SOME OF THE MONSOON MOISTURE CURRENTLY OVER NORTHERN
MEXICO SEEPING NORTH INTO THE SW MTS...ENHANCING ACTIVITY OVER THAT
REGION AS WELL. WAS A LITTLE CONSERVATIVE WITH POPS IN THAT AREA BUT
THIS NEEDS TO BE WATCHED AS LOW LEVEL MOISTURE CAN SURGE NORTH VERY
QUICKLY FROM JUST ONE STRONG CONVECTIVE COMPLEX TO THE SOUTH AT ANY
TIME.
GUIDANCE BEYOND THE WEEKEND CONTINUES TO WAFFLE BACK AND FORTH WHERE
THE HIGH CENTER WILL BE SO CONFIDENCE QUITE LOW FOR NEXT WEEK. GUYER
.FIRE WEATHER...
THE UPPER HIGH IS FORECAST TO CONTINUE AS THE DOMINANT WEATHER
FEATURE THROUGH THE NEXT SEVEN DAYS...ALTHOUGH TWO BACKDOOR FRONTAL
SURGES WILL ADD MOISTURE TO THE EQUATION.
A WEAK COLD FRONT WILL PUSH SOUTHWEST ACROSS THE STATE THURSDAY...
PUSHING LOW LAYER MOISTURE WEST TO THE CONTINENTAL DIVIDE AND
RESULTING IN AN UPTICK IN WETTING SHOWERS AND THUNDERSTORMS. BREEZY
EAST CANYON WINDS ARE FORECAST TO ACCOMPANY THE FRONTAL PASSAGE
THROUGH THE CENTRAL MOUNTAIN CHAIN LATE THURSDAY. RELATIVE HUMIDITIES
WILL TREND UP BEHIND THE FRONT AND TEMPERATURES WILL TREND DOWN
SLIGHTLY THROUGH FRIDAY...ESPECIALLY ALONG/EAST OF THE CENTRAL
MOUNTAIN CHAIN WHERE THE BEST CHANCES FOR WETTING RAIN WILL RESIDE.
ANOTHER WEAK FRONTAL PUSH WILL COME DOWN THE PLAINS SATURDAY
NIGHT...KEEPING GOOD CHANCES FOR WETTING RAINS GOING THROUGH THE
WEEKEND WITH THE BEST CHANCES ALONG/EAST OF THE CENTRAL MOUNTAIN
CHAIN AROUND THE PERIPHERY OF THE UPPER HIGH. OVERNIGHT HUMIDITY
RECOVERIES WILL BE GOOD TO EXCELLENT THROUGH THE WEEKEND THANKS TO
THE ADDED POST-FRONTAL MOISTURE.
RECYCLE MODE IS FORECAST EARLY NEXT WEEK WITH ABOVE NORMAL
TEMPERATURES. LOWER CONFIDENCE FORECAST GOING INTO MID WEEK WITH
DIFFERENCES AMONG THE 12Z MEDIUM RANGE MODEL SOLUTIONS IN THE
PLACEMENT OF THE UPPER HIGH. THE 12Z GFS SHUTS-DOWN THE EAST AND
FAVORS THE WEST AND NORTH FOR WETTING RAINS WITH THE UPPER HIGH
CENTERED OVER FAR WEST TEXAS BY LATE NEXT WEDNESDAY. A TREND BACK
TOWARD LOWER CHANCES FOR WETTING RAINS AND ABOVE NORMAL TEMPERATURE
WOULD FIT THE RECENT PATTERN AND IS THE MOST LIKELY SOLUTION. 11
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
52
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
319 PM MDT TUE AUG 14 2012
.DISCUSSION...
CONVECTION WAS CERTAINLY SLOW TO GET GOING THIS AFTERNOON...THOUGH
ITS NOW HAVING A GROWTH SPURT DESPITE BEING IN RECYCLE MODE. APPEARS
TO BE A BOUNDARY DRAPED ACROSS THE EASTERN PLAINS...ROUGHLY FROM
KLVS TO KTCC. THIS WILL BE AN AREA TO FOCUS ON THRU THE EVENING.
WEDNESDAY SHOULD BE SIMILAR TO TODAY...THOUGH CONVECTIVE COVERAGE
SHOULD BE EVEN LESS AS MOISTURE CONTINUES TO RECYCLE. THUS...WITH
LESS CLOUD COVER AND PRECIPITATION...TEMPERATURES SHOULD BE
WARMER...AND UP TO 10 DEGREES ABOVE NORMAL.
ON THURSDAY...ANOTHER BACK DOOR FRONT WILL MOVE INTO THE NORTHEAST
PLAINS EARLY...COOLING TEMPERATURES 10 TO 15 DEGREES BELOW
WEDNESDAYS NUMBERS. IT WILL CONTINUE TO DIVE SOUTH AND WEST THRU
THE PLAINS DURING THE DAY...THOUGH JUST HOW FAR REMAINS IN QUESTION.
THE GFS HANGS UP THE FRONT ACROSS THE EAST CENTRAL PLAINS...
MEANWHILE...THE NAM CONTINUES TO PLUNGE THE FRONT SOUTH AND WEST THRU
THE CWA. THIS HAS AN IMPACT ON WHERE THE BEST THUNDERSTORM POTENTIAL
WILL BE THURSDAY AFTERNOON AND EVENING. CLIMO WOULD SUGGEST THAT
UPSLOPE FLOW WILL GET THUNDERSTORMS ACROSS THE EAST SLOPES OF THE
CENTRAL MTN CHAIN GOING EARLY IN THE AFTERNOON...THEN STEERING FLOW
SHOULD TAKE THE STORMS INTO THE PLAINS LATER IN THE AFTN/EVE. HAVING
A HARD TIME BELIEVING THE FRONT WILL PUSH THROUGH THE GAPS OF THE
CENTRAL MTN CHAIN DURING THE AFTERNOON HOURS...THUS...WILL HOLD OFF
ON BRINGING IT THRU UNTIL THE EVENING. THEREFORE...KEPT BEST POPS
ALONG/EAST OF THE CENTRAL MTN CHAIN DURING THE DAY THURSDAY.
HOWEVER...THE FRONT WILL PUSH THROUGH AND USHER IN SOME HIGHER
OCTANE MOISTURE INTO THE RIO GRANDE VALLEY AND PERHAPS AS FAR WEST
AS THE CONTINENTAL DIVIDE THURSDAY NIGHT. CERTAINLY DOES NOT LOOK TO
PUSH AS FAR WEST AS EARLY MODEL RUNS SUGGESTED. NONETHELESS...THIS
SHOULD INCREASE CONVECTIVE COVERAGE FOR FRIDAY ACROSS THE WEST...AND
WILL STILL REMAIN ACTIVE ACROSS THE EAST. FRIDAY MAY BE ONE OF THE
BETTER STORM DAYS OF THE SEASON.
AFTER FRIDAY...IT LOOKS LIKE WE WILL BEGIN RECYCLE MODE ONCE
AGAIN...HOWEVER...A SOUTHEASTERLY FETCH OF GULF MOISTURE WILL
CONTINUE ACROSS THE PLAINS. THIS WILL ALLOW STORMS THAT FIRE OVER
THE MOUNTAINS TO MOVE INTO BETTER MOISTURE AS THEY MOVE OVER THE
PLAINS IN NORTHWESTERLY STEERING FLOW. THUS...THE EAST HAS THE BEST
POTENTIAL FOR CONTINUED WETTING RAINS THROUGH THE WEEKEND. FORECAST
CONFIDENCE IS LOW NEXT WEEK WHERE MODELS DIVERGE ON THE PLACEMENT OF
THE UPPER HIGH.
34
&&
.FIRE WEATHER...
CONVECTION FIRING ACROSS THE REGION THIS AFTERNOON WILL BECOME MORE
WIDESPREAD AS THE EVENING PROGRESSES. STEERING FLOW IS TO THE EAST
SOUTHEAST NEAR 15 MPH ACROSS THE NORTH AND AROUND 5 MPH ACROSS THE
SOUTH. PRECIPITABLE WATER VALUES AND SURFACE DEWPOINT VALUES ARE
CERTAINLY HIGH ENOUGH TODAY TO SUPPORT LOCALLY HEAVY RAINFALL AS
WAS THE CASE MONDAY. DECENT PRECIP COVERAGE WILL LEAD TO EXCELLENT
RECOVERIES ACROSS PORTIONS OF THE NORTHERN MTS AND NE PLAINS...WHILE
THE REMAINDER OF THE AREA SEES GOOD RECOVERIES.
WEDNESDAY WILL BE SLIGHLTY DRIER THAN TODAY WITH MIN RH VALUES TO
TREND 5 TO 10 PCT LOWER. A 700-500MB MID LEVEL DRY LAYER ALREADY
EVIDENCED ON WATER VAPOR OVER ARIZONA WILL ATTEMPT TO SHIFT OF
CENTRAL PORTIONS OF THE STATE. STORMS WILL THUS WILL GUSTIER AND
WETTING RAINFALL FOOTPRINTS NOT AS LARGE. HAINES VALUES WILL BE
AROUND 5 FOR MANY CENTRAL AND WESTERN AREAS. NO SIGNIFICANT WINDS
ARE ANTICIPATED OUTSIDE OF CONVECTION.
A BACK DOOR FRONTAL INTRUSION IS THEN SLATED TO ARRIVE OVER THE E
PLAINS THURSDAY...WITH ANOTHER DECENT PUSH OF LOW LEVEL MOISTURE.
THIS WILL ENHANCE COVERAGE AGAIN ESPECIALLY ALONG AND EAST OF THE
CENTRAL MT CHAIN. LOCALLY HEAVY RAINFALL IS POSSIBLE. WINDS BEHIND
THE FRONTAL BOUNDARY WILL BE NEAR BREEZY AS WELL WITH A MODERATELY
STRONG PRESSURE GRADIENT IN ITS WAKE. THIS FRONT WILL PUSH THRU
THE CENTRAL MT CHAIN THURSDAY EVENING WITH GAP WINDS OF 15 TO 25
WITH GUSTS UP TO 35 MPH. THE EVENT MAY BE STRONGER IF CONVECTIVE
COMPLEX FORMS OVER THE PLAINS. MIN RH VALUES WILL TREND MUCH
HIGHER FOR THE EAST BEHIND THIS FRONT...WHILE THE WEST REMAINS
IN THE 20 PCT RANGE. RECOVERIES THURSDAY NIGHT WILL BE EXCELLENT
FOR MOST OF THE EAST AND THE HIGH TERRAIN.
ANOTHER ACTIVE DAY IS ON TAP FOR FRIDAY WITH WEAK STEERING FLOW...
DEEP MOISTURE...AND PLENTY OF INSTABILITY. LOCALLY HEAVY RAINFALL
THREAT WILL REMAIN ELEVATED. THE UPPER HIGH BACKS OFF INTO ARIZONA
SATURDAY AND SUNDAY ALLOWING NW FLOW TO DOMINATE HEAVY RAINFALL
POTENTIAL ALONG AND EAST OF THE CENTRAL MT CHAIN. MAX TEMPS THRU
THIS ENTIRE PERIOD WILL BE NEAR TO SLIGHTLY BELOW NORMAL FOR THE
EASTERN PLAINS AND SLIGHTLY ABOVE NORMAL OUT WEST. MIN TEMPS WILL
BE ABOVE NORMAL ACROSS THE BOARD.
GUYER
&&
.AVIATION...
18Z TAF CYCLE
AN UPPER DISTURBANCE SLIDING SE OVER NORTHERN NM THIS AFTERNOON
WILL FORCE SHRA/TSRA DEVELOPMENT AFT 20Z. STEERING FLOW WILL BE TO
THE SE NEAR 15 KTS. GREATEST CONFIDENCE FOR STORM IMPACTS IN THIS
FLOW WILL BE KLVS...KSAF...KTCC. HEAVY RAIN AND GUSTY WINDS MAY
REDUCE VSBYS/ CIGS DOWN AS LOW AS 030 AND 2SM HOWEVER CONFIDENCE
NOT HIGH ENOUGH AT ANY SPECIFIC LOCALE SO TEMPO WILL HOLD VFR FOR
NOW. LATEST RUC AND HRRR MODELS INDICATE CONVECTION MAY ORGANIZE
OVER THE EAST AS AREA OF STRATIFORM PRECIP AFTER 02Z SO POTENTIAL
EXISTS FOR LONGER DURATION VFR BKN CIGS AND -RA POSSIBLE FOR KTCC
AND KROW. CLOUDS EXPECTED TO BREAK TO SCT MID LEVEL CLOUDS AFTER
MIDNIGHT THEN CLEAR BY SUNRISE ALL AREAS. GUYER/24
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 61 92 61 93 / 20 10 10 20
DULCE........................... 49 87 50 86 / 30 20 20 30
CUBA............................ 54 88 55 87 / 30 20 20 30
GALLUP.......................... 55 88 55 89 / 20 20 20 20
EL MORRO........................ 53 83 53 82 / 20 20 20 30
GRANTS.......................... 53 88 55 88 / 20 20 20 20
QUEMADO......................... 57 88 56 86 / 30 20 20 30
GLENWOOD........................ 62 92 62 91 / 20 20 20 20
CHAMA........................... 44 82 47 81 / 30 30 30 40
LOS ALAMOS...................... 59 85 60 83 / 30 30 20 40
PECOS........................... 57 83 58 79 / 30 30 30 50
CERRO/QUESTA.................... 52 79 53 78 / 30 30 30 50
RED RIVER....................... 47 74 47 70 / 30 40 40 60
ANGEL FIRE...................... 43 77 45 71 / 30 40 30 60
TAOS............................ 51 85 53 83 / 30 30 30 50
MORA............................ 53 79 55 75 / 30 30 30 50
ESPANOLA........................ 58 90 59 89 / 30 20 20 30
SANTA FE........................ 58 87 60 83 / 30 30 20 40
SANTA FE AIRPORT................ 59 90 60 87 / 30 20 20 30
ALBUQUERQUE FOOTHILLS........... 65 92 67 90 / 30 10 20 30
ALBUQUERQUE HEIGHTS............. 68 93 69 91 / 20 10 20 20
ALBUQUERQUE VALLEY.............. 66 95 66 93 / 20 10 20 20
ALBUQUERQUE WEST MESA........... 67 94 67 92 / 20 10 20 20
LOS LUNAS....................... 65 94 66 92 / 20 10 20 20
RIO RANCHO...................... 67 94 67 92 / 20 10 20 20
SOCORRO......................... 67 96 68 95 / 20 10 20 20
SANDIA PARK/CEDAR CREST......... 58 88 62 87 / 30 20 20 40
TIJERAS......................... 61 89 62 89 / 30 20 20 30
MORIARTY/ESTANCIA............... 58 89 59 84 / 30 20 20 40
CLINES CORNERS.................. 58 88 60 80 / 30 20 20 50
GRAN QUIVIRA.................... 62 88 61 86 / 30 20 20 30
CARRIZOZO....................... 63 92 64 90 / 20 20 20 30
RUIDOSO......................... 60 83 60 82 / 30 30 30 40
CAPULIN......................... 57 85 57 74 / 30 20 30 40
RATON........................... 58 91 57 82 / 30 20 30 40
SPRINGER........................ 59 88 59 82 / 30 20 30 40
LAS VEGAS....................... 55 86 57 79 / 30 30 30 50
CLAYTON......................... 62 92 60 79 / 20 20 30 40
ROY............................. 62 89 62 79 / 30 20 30 40
CONCHAS......................... 68 95 69 87 / 30 20 20 40
SANTA ROSA...................... 68 96 67 89 / 30 20 20 50
TUCUMCARI....................... 68 99 68 89 / 20 20 20 40
CLOVIS.......................... 67 96 66 89 / 20 20 20 30
PORTALES........................ 67 97 67 90 / 20 20 20 30
FORT SUMNER..................... 70 96 70 91 / 20 10 20 30
ROSWELL......................... 71 100 71 97 / 20 10 10 20
PICACHO......................... 65 93 66 91 / 20 20 20 30
ELK............................. 62 86 63 86 / 30 20 20 30
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
34
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1158 AM MDT TUE AUG 14 2012
.AVIATION...
18Z TAF CYCLE
AN UPPER DISTURBANCE SLIDING SE OVER NORTHERN NM THIS AFTERNOON WILL
FORCE SHRA/TSRA DEVELOPMENT AFT 20Z. STEERING FLOW WILL BE TO THE SE
NEAR 15 KTS. GREATEST CONFIDENCE FOR STORM IMPACTS IN THIS FLOW WILL
BE KLVS...KSAF...KTCC. HEAVY RAIN AND GUSTY WINDS MAY REDUCE VSBYS/
CIGS DOWN AS LOW AS 030 AND 2SM HOWEVER CONFIDENCE NOT HIGH ENOUGH AT
ANY SPECIFIC LOCALE SO TEMPO WILL HOLD VFR FOR NOW. LATEST RUC AND
HRRR MODELS INDICATE CONVECTION MAY ORGANIZE OVER THE EAST AS AREA
OF STRATIFORM PRECIP AFTER 02Z SO POTENTIAL EXISTS FOR LONGER DURATION
VFR BKN CIGS AND -RA POSSIBLE FOR KTCC AND KROW. CLOUDS EXPECTED TO
BREAK TO SCT MID LEVEL CLOUDS AFTER MIDNIGHT THEN CLEAR BY SUNRISE
ALL AREAS. GUYER/24
&&
.PREV DISCUSSION...332 AM MDT TUE AUG 14 2012...
A MOISTURE RECYCLE MODE DAY TODAY AS SIGNIFICANT LOW LVL MOISTURE
INFLUX HAS PRETTY MUCH ENDED...ESPECIALLY NW TWO THIRDS OR SO OF
NM. WITH THE PREVIOUS BACK DOOR FRONT BRING IN SOME ADDTL LOW LVL
MOISTURE AND MID AND HIGH LVL MOISTURE STILL SNEAKING TO SOME
DEGREE INTO THE S SIDE OF THE EVER PRESENT UPPER HIGH STRETCHING
FROM W TX INTO S AZ. THUS IT HAS BECOME ONE OF THE SO CALLED
DIRTIER HIGHS THIS FCSTR HAS SEEN IN MANY A MOON. SO AT LEAST
ENOUGH MOISTURE REMAINS TO STILL REACT WITH DAYTIME HEATING AND
THE OCCASIONAL WEAK DISTURBANCE ROTATING AROUND THE HIGH PRESSURE
CENTER TO TRIGGER A SCATTERING OF SHOWERS AND STORMS. COVERAGE
TODAY SHOULD BE NEAR TO SLIGHTLY BELOW MONDAY/S LEVELS AND
RAINFALL AMTS FROM THE STRONGEST STORMS LIKELY TO BE A BIT
LESS...BUT A FEW HEAVY RAINERS ARE STILL QUITE LIKELY. GFS AND NAM
MODELS STILL SHOW A MINOR/WEAK WIND SHIFT INTO THE NE A LITTLE
LATER TODAY...BUT NOT MUCH IMPACT ON WX EXPECTED THERE OTHER THAN
THE WIND SHIFT. DOWNWARD TREND OF STORM COVERAGE SHOULD CONTINUE
ON WED. THE HIGH TEMPERATURES TODAY AND WED WILL BE MOSTLY ABOVE
NORMAL.
A SHORT WAVE TROUGH PASSING N AND NE OF NM THU WILL EJECT A BACK
DOOR FRONT INTO THE NE. THIS FRONT WILL DRIVE S AND W LATER THU
AND THU NIGHT BRINGING ANOTHER MODERATE E CANYON WIND EVENT INTO
THE RIO GRANDE VALLEY. THIS FRESH INFLUX OF MOISTURE WILL ENHANCE
STORM COVERAGE FOR THU AND FRI OVER THE FORECAST AREA. SHOULD
BRING A ROUGHLY 5 TO NEARLY 15 DEGREE TEMPERATURE DROP IN THE NE
THU AND SE ON FRI. LESSER DROPS FARTHER WEST ON FRI. MOISTURE
RECYCLING MODE RETURNS FOR THE UPCOMING WEEKEND AND EARLY NEXT
WEEK. OVERALL COVERAGE DURING THIS TIME SHOULD DIMINISH. MEANWHILE
TEMPERATURES IN THE E WILL RETURN TO ABOVE NORMAL READINGS.
43
.FIRE WEATHER...
CRITICAL FIRE WEATHER...NOT EXPECTED THROUGH NEXT WEEKEND AND INTO
MONDAY OF THE FOLLOWING WEEK.
MODELS...IN ROUGH AGREEMENT THROUGH THE WEEKEND AND INTO THE
FOLLOWING WORK WEEK IN A WEAKLY FORCED PATTERN. RIDGE CENTROID OVER
THE SOUTHWESTERN U.S. WILL AMPLIFY PATTERN WITH RIDGE EXTENSION WELL
INTO THE PACIFIC NORTHWEST HEADING INTO THE WEEKEND. AS RIDGE
CENTROID SHIFTS WESTWARD TO ARIZONA AND SOUTHERN
CALIFORNIA...AMPLIFIED PATTERN WILL START BRINGING QUICK HITTER
DISTURBANCES OUT OF THE PACIFIC NORTHWEST SOUTHEAST TO TEXAS AND
OKLAHOMA...AND SOME OF THESE WILL CLIP THE NORTHEAST CORNER OF NEW
MEXICO ON THE WAY. RIDGE WILL EXPAND BACK TO THE EAST LATE MONDAY TO
SHIFT THE DISTURBANCE TRACK AWAY FROM NEW MEXICO...AND THEN THE
CENTROID REDEVELOPS OVER NEW MEXICO BY MIDWEEK NEXT WEEK.
FOR TODAY...BROAD SCATTERED SHOWER AND THUNDERSTORM COVERAGE ON TAP
BY THIS AFTERNOON...WITH BEST CHANCES FOR WETTING RAIN OVER THE
NORTHERN MOUNTAINS CLOSE TO THE COLORADO LINE. SURFACE WINDS WILL
SHIFT TO THE NORTHWEST OVER THE WESTERN END OF THE STATE...WITH WIND
DIRECTIONS REMAINING MORE WESTERLY CENTRAL AND SOUTHWESTERLY OVER
THE EASTERN PLAINS. WITH TEMPERATURES REMAINING 3 TO 8 DEGREES ABOVE
NORMAL...MINIMUM HUMIDITIES WILL RUN MAINLY IN THE UPPER TEENS AND
LOW 20S PCT WITH GOOD TO EXCELLENT HUMIDITY RECOVERIES OVERNIGHT.
VENTILATION GENERALLY IN GOOD SHAPE...WITH SOME DEGRADATION OVER
THE NORTHERN TIER AND NORTHEAST HIGHLANDS AND PLAINS IN WEAKER
TRANSPORT WINDS.
FOR WEDNESDAY...RIDGE CORE CENTERED OVER THE DRAGOON MOUNTAINS OF
SOUTHEAST ARIZONA....AND WILL HELP REDUCE THUNDERSTORM COVERAGE AND
INTENSITY FOR A GENERAL DOWN TICK IN CONVECTIVE ACTIVITY. HIGH
COUNTRY WEST AND CENTRAL FAVORED...WITH SOME ENHANCEMENT OVER THE
NORTHEAST HIGHLANDS AND NORTHEAST PLAINS IN VICINITY OF WEAK TROUGH
AXIS. WIND SPEEDS REMAINING LIGHT WITH STEADY TEMPERATURE PROFILES
AND WEAK DRYING TREND. MINIMUM HUMIDITIES REMAINING PRETTY MUCH IN
THE UPPER TEENS AND LOW 20S PCT...WITH MORE TEENS THAN 20S WEDNESDAY
OVER THOSE OBSERVED ON TUESDAY. VENTILATION GENERALLY GOOD...WITH
MARGINAL CONDITIONS CONTINUING OVER THE NORTHEAST PLAINS.
FOR THURSDAY...COLD FRONT OFF THE FRONT RANGE OF THE ROCKIES AND
CENTRAL PLAINS WILL PUSH INTO THE NORTHEAST PLAINS THURSDAY DAYTIME
AND ROLL SOUTHWARD AND BULGE WESTWARD AGAINST THE CENTRAL MOUNTAIN
CHAIN BY THURSDAY NIGHT. WINDS PICKING UP STRONG EASTERLY COMPONENT
AS THE FRONT MOVES IN...WITH SOME UPSLOPE FLOW SUPPORTING AN
INCREASE IN THUNDERSTORM COVERAGE AND INTENSITY. STORMS MOST LIKELY
OVER THE SANGRE DE CRISTO SUMMITS AND EASTERN SLOPES...WITH HIGH
COUNTRY STORM STARTS EXPANDING STEADILY TO VALLEYS AND PLAINS
THROUGH THE DAY. DOUBLE DIGIT TEMPERATURE DROPS OVER THE EAST...AND
A FEW DEGREES DOWN OVER THE CENTRAL AND WEST WILL BRING MAXIMUM
TEMPERATURES TO WITHIN A FEW DEGREES OF NORMAL...WITH 5 TO 10 DEGREE
DEPARTURES BELOW NORMAL OVER THE NORTHEAST. MINIMUM HUMIDITIES
BOOSTING INTO THE UPPER 20S AND 30S PCT...WITH THE LAST OF THE TEENS
PCT OVER THE NORTHWEST PLATEAU. NO VENTILATION ISSUES EXPECTED.
OVERNIGHT...GOOD TO EXCELLENT HUMIDITY RECOVERIES...AND EASTERLY GAP
WINDS DEVELOPING THROUGH THE CENTRAL MOUNTAIN CHAIN AND BLOWING OUT
OVER THE RIO GRANDE VALLEY INTO EARLY FRIDAY MORNING.
OUTLOOK...FRIDAY THROUGH THE WEEKEND...SLOW BUT STEADY TEMPERATURE
REBOUND AND WEAK DRYING TREND AS RIDGE CENTROID SHIFTS TO WESTERN
ARIZONA...AND NORTHWEST FLOW IS ABLE TO DENT THE EASTERN EDGE OF THE
RIDGE AND BRING SOME QUICK HITTER DISTURBANCES ACROSS THE NORTHEAST
CORNER OF NEW MEXICO THROUGH SATURDAY. RIDGE EXPANDING BACK TO THE
EAST ON SUNDAY TO SHIFT NORTHWEST FLOW OUT OF NEW MEXICO INTO THE
HEART OF TEXAS...AND RETURNING A RECYCLING CONVECTIVE PATTERN TO THE
STATE. THIS WILL SHOW UP AS A GENERAL TREND TOWARD REDUCED
THUNDERSTORM COVERAGE AND INTENSITY. WINDS GENERALLY SOUTHEASTERLY
VEERING TO SOUTHERLY THROUGH THE WEEKEND. SOME MARGINAL VENTILATION
CENTRAL AND SOUTHWEST...BUT GOOD CONDITIONS ELSEWHERE THROUGH THE
WEEKEND.
SHY
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
220 PM EDT TUE AUG 14 2012
.SYNOPSIS...
TODAY THROUGH WEDNESDAY, LOW PRESSURE WILL TRACK FROM THE OHIO
VALLEY NORTHEAST ACROSS WESTERN NEW YORK AND THEN INTO SOUTHERN
QUEBEC. THIS SYSTEM WILL BRING SHOWERS AND THUNDERSTORMS TO THE
AREA PRIMARILY THIS AFTERNOON AND EVENING. UNSETTLED WEATHER WILL
CONTINUE THROUGH WEDNESDAY BEFORE HIGH PRESSURE BRINGS DRY AND
SEASONAL CONDITIONS ON THURSDAY. ANOTHER COLD FRONT WILL BRING A
CHANCE FOR MORE SHOWERS AND THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1230 PM UPDATE...CURRENT FORECAST IN GOOD SHAPE. CONVECTION WILL
INCREASE ACROSS THE WESTERN FA DURING THE NEXT COUPLE OF HOURS AND
TRACK EAST THROUGH CENTRAL NY/NE PA THROUGH THIS EVENING. SPC SITE
SHOWS ML CAPE VALUES UP TO 500 J/KG ACROSS THE WESTERN AND PARTS
OF THE CENTRAL SOUTHERN TIER WHERE SKIES ARE PARTLY SUNNY. AS
DAYTIME HEATING CONTINUES ML CAPES BTW 800-1200 J/KG MAY BE
REALIZED WHICH COULD LEAD TO A FEW SVR STORMS LATER THIS AFTERNOON
INTO THE EVENING HOURS.
10 AM UPDATE...AREA OF SHOWERS AND ISOLATED THUNDERSTORMS NOW
DEPARTING THE WESTERN CATSKILLS AND POCONOS AS MID LEVEL SHORT
WAVE AND WEAK ISENTROPIC LIFT SHIFTS EAST. SATELLITE SHOWS
CLEARING SKIES ACROSS WESTERN NY AND INTO THE CENTRAL SOUTHERN
TIER. THIS AREA OF CLEARING IS EXPECTED TO MAKE PROGRESS ACROSS
THE FINGER LAKES REGION INTO THE LAKE PLAIN AND PARTS OF THE
SOUTHERN TIER. THIS WILL DESTABILIZE THE ATMOSPHERE PRIOR TO THE
NEXT MORE WIDESPREAD ROUND OF SHOWERS AND THUNDERSTORMS AS SFC LOW
TRACKS INTO WESTERN NEW YORK. CONVECTION WILL INCREASE LATER THIS
AFTERNOON INTO THE EVENING WITH STILL THE THREAT THAT A FEW MAY
BECOME SEVERE. JUST MINOR ADJUSTMENTS TO SHORT TERM POPS/CLOUDS/TEMPS.
.PREVIOUS DISC...
FIRST ROUND OF SHOWERS WILL BE PASSING OFF TO THE EAST
OF THE AREA BY EARLY AFTERNOON. KEY TO STORM REDEVELOPMENT AND ANY
SEVERE POTENTIAL WILL BE HOW MUCH CLEARING CAN OCCUR IN THE WAKE
OF THESE SHOWERS THROUGH MID- AFTERNOON... BEFORE ANOTHER WAVE
ROTATING AROUND THE UPPER TROUGH BRINGS ANOTHER ROUND OF
CONVECTION LATER THIS AFTERNOON INTO THIS EVENING. CURRENTLY SOME
CLEARING IS OCCURRING BEHIND THE INITIAL WAVE OVER OHIO... AND AT
THIS POINT EXPECT SOME OF THAT CLEARING TO WORK EAST ACROSS OUR
AREA THIS AFTERNOON. SREF CAPE FORECAST PLUMES INDICATE A WIDE
RANGE OF POSSIBLE CAPES THIS AFTERNOON... WITH MEAN VALUES NEAR
1000 J/KG. NAM/GFS AND RUC ALSO INDICATING NEAR 1000 J/KG POSSIBLE
THIS AFTERNOON. THE COMBINATION OF A WEAKLY UNSTABLE ENVIRONMENT
WITH DEEP LAYER BULK SHEAR VALUES OF 20 TO 30 KTS WILL BE ENOUGH
TO PROMOTE SOME ORGANIZED CONVECTION LATER THIS AFTERNOON INTO
THIS EVENING. HOWEVER STRONG FORCING FOR A WIDESPREAD SEVERE EVENT
APPEARS TO BE LACKING AS LOW-LEVEL CONVERGENCE WILL BE WEAK IN
ASSOCIATION WITH A WEAK... POORLY ORGANIZED SURFACE LOW... AND
MID-TO-UPPER LEVEL HEIGHT FALLS WILL ALSO BE MINIMAL. BASED ON ALL
OF THE ABOVE REASONING EXPECT A FEW STRONG TO MARGINALLY SEVERE
STORMS TO DEVELOP LATER THIS AFTERNOON WITH ISOLATED SEVERE
REPORTS LIKELY BUT NOT A WIDESPREAD EVENT. SPC HAS THE SOUTHERN
HALF OF OUR AREA IN A SLIGHT RISK OF SEVERE WEATHER TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
AS IS TYPICAL FOR THIS TIME OF YEAR... SURFACE LOW PRESSURE AND
ASSOCIATED FRONTAL ZONES WILL BE SLOW TO MOVE EAST... AND THESE
FEATURES WILL LIKELY LINGER OVER THE AREA INTO WEDNESDAY. EXPECT
STORM COVERAGE TO DIMINISH LATER THIS EVENING... BUT A FEW STORMS
COULD LINGER THROUGH TONIGHT AS THE ATMOSPHERE REMAINS WEAKLY
UNSTABLE. NAM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT WEAK SURFACE
LOW PRESSURE WILL EVENTUALLY DEVELOP SOMEWHERE OVER SOUTHERN PA OR
NEW JERSEY ON WEDNESDAY WITH THE SUPPORTING UPPER TROUGH LINGERING
JUST TO THE WEST. THIS WILL KEEP THE CHANCE FOR SHOWERS AND
SCATTERED THUNDERSTORMS GOING THROUGH WEDNESDAY. BOTH THE
INSTABILITY AND SHEAR WILL BE LESS ON WEDNESDAY COMPARED TO TODAY
AND AS A RESULT THE SEVERE THREAT WILL BE LOWER. ACTUALLY WOULD
EXPECT THE THREAT FOR LOCALIZED HEAVY RAIN TO BE GREATER THAN THE
SEVERE THREAT ON WEDNESDAY GIVEN EXPECTED LIGHT WIND FIELDS ALOFT.
THE UPPER TROUGH FINALLY MOVES EAST OF THE AREA BY THURSDAY...
BRINGING A RETURN TO DRY SEASONABLY WARM WEATHER.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
2 PM UPDATE...
WE WILL START OFF THE EXTENDED PERIOD UNSETTLED WITH A TREND
TOWARD DRIER BUT COOLER WEATHER OVER THE WEEKEND. BEST SHOT AT
PRECIPITATION IN THIS PERIOD WILL COME FRIDAY NIGHT WITH A FRONT
MOVING THROUGH. THE 12Z GFS AND CANADIAN ARE FASTER WITH THE
FRONT...DRYING US OUT BY 12Z SATURDAY. THE 0Z EURO IS MUCH
SLOWER AND ACTUALLY SLOWER THAN THE PREVIOUS RUNS OF THIS MODEL.
FOR NOW WILL LEAVE IN CHANCE POPS OVER THE FAR SOUTHEAST THROUGH
EARLY SATURDAY MORNING. WE MAY BE ABLE TO YANK THESE THOUGH IF THE
12Z EURO COMES IN FASTER...MORE IN LINE WITH THE OTHER LONG RANGE GUIDANCE.
WE SHOULD SEE A PERIOD OF DRY WEATHER FOR THE REST OF SATURDAY
INTO MOST OF SUNDAY BEFORE WE BEGIN TO SEE THE INFLUENCE OF A
DIGGING H5 TROF OVER THE OHIO VALLEY. BOTH THE GFS AND CANADIAN
ARE A BIT MORE AGGRESSIVE IN SENDING MOISTURE ARE WAY BY LATE
SUNDAY...WHICH MAY BE ENOUGH WITH FALLING H5 HEIGHTS FOR SOME
ISOLATED SHOWERS ESPECIALLY WEST OF I-81. STILL FEEL THE BETTER THREAT
FOR CONVECTIVE SHOWERS WITH THE UPPER LEVEL TROF WILL INCREASE
THROUGH MONDAY...BEFORE REACHING A PEAK TUESDAY WITH THE TROF AXIS
MOVING THROUGH. THE BIGGER STORY THIS WEEKEND WILL LIKELY BE THE
TEMPERATURES AS 850 TEMPS REMAIN IN THE SINGLE DIGITS...WHICH WILL
KEEP HIGHS IN THE LOWER TO MIDDLE 70S. PERHAPS A SIGN FALL IS NOT
TOO FAR AROUND THE CORNER.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
200 PM UPDATE...A FEW SHOWERS ARE POSSIBLE WITH MAINLY VFR
CONDITIONS AND A GRADUAL LOWERING OF THE MID DECK TO AROUND 6KFT
THROUGH 21Z. AFTER THAT...AN AREA OF SHOWERS AND THUNDERSTORMS NOW
DEVELOPING ACROSS WESTERN NY WILL MOVE ACROSS THE TERMINALS
ROUGHLY BETWEEN 21Z AND 02Z. BEST WINDOW FOR STORMS WITH MVFR
VSBYS AT THE NY TERMINALS WILL BE BETWEEN 21Z AND 0Z...AND BETWEEN
00Z AND 02Z AT KAVP. AFTER THE STORMS CLEAR VFR THROUGH THE FIRST
HALF OF THE OVERNIGHT.
TOWARD DAYBREAK MVFR CIGS AND VSBYS ARE POSSIBLE AT THE SOUTHERN
NY TERMINALS AND KAVP. IT IS POSSIBLE WE MAY SEE IFR CIGS AT THE
ELEVATED SITES BUT TOO LOW OF CONFIDENCE TO INCLUDE AT THE MOMENT.
AFTER A BRIEF BREAK...MVFR CIGS ARE POSSIBLE AGAIN ESPECIALLY
KITH/KBGM/KRME WITH THE PASSAGE OF A FRONT BY MID WEDNESDAY MORNING.
WINDS 5 TO 10 KTS OUT OF THE SOUTH THROUGH LATE AFTERNOON. NEAR
CALM OR LIGHT/VARIABLE WINDS TONIGHT. WINDS VEER INTO THE
NORTHWEST BY MID WEDNESDAY MORNING AROUND 5 KTS.
OUTLOOK...
WED NGT-FRI AM...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY EACH
MRNG.
FRI PM...MVFR IN SHOWERS/TSRA POSSIBLE.
SAT/SUN...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE/RRM
NEAR TERM...MSE/RRM
SHORT TERM...MSE
LONG TERM...HEDEN
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1232 PM EDT TUE AUG 14 2012
.SYNOPSIS...
TODAY THROUGH WEDNESDAY, LOW PRESSURE WILL TRACK FROM THE OHIO
VALLEY NORTHEAST ACROSS WESTERN NEW YORK AND THEN INTO SOUTHERN
QUEBEC. THIS SYSTEM WILL BRING SHOWERS AND THUNDERSTORMS TO THE
AREA PRIMARILY THIS AFTERNOON AND EVENING. UNSETTLED WEATHER WILL
CONTINUE THROUGH WEDNESDAY BEFORE HIGH PRESSURE BRINGS DRY AND
SEASONAL CONDITIONS ON THURSDAY. ANOTHER COLD FRONT WILL BRING A
CHANCE FOR MORE SHOWERS AND THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1230 PM UPDATE...CURRENT FORECAST IN GOOD SHAPE. CONVECTION WILL
INCREASE ACROSS THE WESTERN FA DURING THE NEXT COUPLE OF HOURS AND
TRACK EAST THROUGH CENTRAL NY/NE PA THROUGH THIS EVENING. SPC SITE
SHOWS ML CAPE VALUES UP TO 500 J/KG ACROSS THE WESTERN AND PARTS
OF THE CENTRAL SOUTHERN TIER WHERE SKIES ARE PARTLY SUNNY. AS
DAYTIME HEATING CONTINUES ML CAPES BTW 800-1200 J/KG MAY BE
REALIZED WHICH COULD LEAD TO A FEW SVR STORMS LATER THIS AFTERNOON
INTO THE EVENING HOURS.
10 AM UPDATE...AREA OF SHOWERS AND ISOLATED THUNDERSTORMS NOW
DEPARTING THE WESTERN CATSKILLS AND POCONOS AS MID LEVEL SHORT
WAVE AND WEAK ISENTROPIC LIFT SHIFTS EAST. SATELLITE SHOWS
CLEARING SKIES ACROSS WESTERN NY AND INTO THE CENTRAL SOUTHERN
TIER. THIS AREA OF CLEARING IS EXPECTED TO MAKE PROGRESS ACROSS
THE FINGER LAKES REGION INTO THE LAKE PLAIN AND PARTS OF THE
SOUTHERN TIER. THIS WILL DESTABILIZE THE ATMOSPHERE PRIOR TO THE
NEXT MORE WIDESPREAD ROUND OF SHOWERS AND THUNDERSTORMS AS SFC LOW
TRACKS INTO WESTERN NEW YORK. CONVECTION WILL INCREASE LATER THIS
AFTERNOON INTO THE EVENING WITH STILL THE THREAT THAT A FEW MAY
BECOME SEVERE. JUST MINOR ADJUSTMENTS TO SHORT TERM POPS/CLOUDS/TEMPS.
.PREVIOUS DISC...
FIRST ROUND OF SHOWERS WILL BE PASSING OFF TO THE EAST
OF THE AREA BY EARLY AFTERNOON. KEY TO STORM REDEVELOPMENT AND ANY
SEVERE POTENTIAL WILL BE HOW MUCH CLEARING CAN OCCUR IN THE WAKE
OF THESE SHOWERS THROUGH MID- AFTERNOON... BEFORE ANOTHER WAVE
ROTATING AROUND THE UPPER TROUGH BRINGS ANOTHER ROUND OF
CONVECTION LATER THIS AFTERNOON INTO THIS EVENING. CURRENTLY SOME
CLEARING IS OCCURRING BEHIND THE INITIAL WAVE OVER OHIO... AND AT
THIS POINT EXPECT SOME OF THAT CLEARING TO WORK EAST ACROSS OUR
AREA THIS AFTERNOON. SREF CAPE FORECAST PLUMES INDICATE A WIDE
RANGE OF POSSIBLE CAPES THIS AFTERNOON... WITH MEAN VALUES NEAR
1000 J/KG. NAM/GFS AND RUC ALSO INDICATING NEAR 1000 J/KG POSSIBLE
THIS AFTERNOON. THE COMBINATION OF A WEAKLY UNSTABLE ENVIRONMENT
WITH DEEP LAYER BULK SHEAR VALUES OF 20 TO 30 KTS WILL BE ENOUGH
TO PROMOTE SOME ORGANIZED CONVECTION LATER THIS AFTERNOON INTO
THIS EVENING. HOWEVER STRONG FORCING FOR A WIDESPREAD SEVERE EVENT
APPEARS TO BE LACKING AS LOW-LEVEL CONVERGENCE WILL BE WEAK IN
ASSOCIATION WITH A WEAK... POORLY ORGANIZED SURFACE LOW... AND
MID-TO-UPPER LEVEL HEIGHT FALLS WILL ALSO BE MINIMAL. BASED ON ALL
OF THE ABOVE REASONING EXPECT A FEW STRONG TO MARGINALLY SEVERE
STORMS TO DEVELOP LATER THIS AFTERNOON WITH ISOLATED SEVERE
REPORTS LIKELY BUT NOT A WIDESPREAD EVENT. SPC HAS THE SOUTHERN
HALF OF OUR AREA IN A SLIGHT RISK OF SEVERE WEATHER TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
AS IS TYPICAL FOR THIS TIME OF YEAR... SURFACE LOW PRESSURE AND
ASSOCIATED FRONTAL ZONES WILL BE SLOW TO MOVE EAST... AND THESE
FEATURES WILL LIKELY LINGER OVER THE AREA INTO WEDNESDAY. EXPECT
STORM COVERAGE TO DIMINISH LATER THIS EVENING... BUT A FEW STORMS
COULD LINGER THROUGH TONIGHT AS THE ATMOSPHERE REMAINS WEAKLY
UNSTABLE. NAM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT WEAK SURFACE
LOW PRESSURE WILL EVENTUALLY DEVELOP SOMEWHERE OVER SOUTHERN PA OR
NEW JERSEY ON WEDNESDAY WITH THE SUPPORTING UPPER TROUGH LINGERING
JUST TO THE WEST. THIS WILL KEEP THE CHANCE FOR SHOWERS AND
SCATTERED THUNDERSTORMS GOING THROUGH WEDNESDAY. BOTH THE
INSTABILITY AND SHEAR WILL BE LESS ON WEDNESDAY COMPARED TO TODAY
AND AS A RESULT THE SEVERE THREAT WILL BE LOWER. ACTUALLY WOULD
EXPECT THE THREAT FOR LOCALIZED HEAVY RAIN TO BE GREATER THAN THE
SEVERE THREAT ON WEDNESDAY GIVEN EXPECTED LIGHT WIND FIELDS ALOFT.
THE UPPER TROUGH FINALLY MOVES EAST OF THE AREA BY THURSDAY...
BRINGING A RETURN TO DRY SEASONABLY WARM WEATHER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
330 AM UPDATE...NO MAJOR CHGS NEEDED TO LONG TERM AT THIS TIME.
STILL SHOWING STRONG CDFNT EXPECTED TO PASS THRU FRIDAY WITH CHC
SHRAS/TSTMS. WUD NOT BE SURPRISED TO SEE POPS BOOSTED INTO THE
LKLY CATEGORY.
LONG TERM MODELS (BOTH GFS AND ECMWF) INDICATE UL TROFFING THRU
THE END OF THE PD WITH HUDSON BAY VORTEX HANGING ON THRU EARLY
NEXT WEEK. HIPRES BHND CDFNT BUILDING IN MAY LEAD TO CLRNG SKIES
SAT NGT INTO SUNDAY THO GNRLY CLOUDY AND COOLER CONDS WL BE THE
RULE AFT THE WEEKEND WITH UL TROF HANGING ON.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
630 AM UPDATE...
VFR CONDS THIS MORNING. AREA OF SHOWERS MOVING INTO KAVP TERMINAL
AT THIS TIME WITH LITTLE IN THE WAY OF MVFR RESTRICTIONS EXPECTED.
EXPECT PREDOMINANT SHOWERS TO LAST THROUGH 14Z THIS MORNING BEFORE
A BRIEF BREAK BEFORE AFTERNOON CONVECTION.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AFTER 18Z ACROSS
WESTERN AND NORTHERN TERMINALS. HAVE INCLUDED MENTION OF THUNDER
ACROSS ALL TERMINALS FROM 20Z TO 00Z THIS EVENING WITH LITTLE IN
THE WAY OF RESTRICTIONS.
BKN-OVC CIGS EXPECTED AFTER 00Z. CONDITIONS DO NOT WARRANT MENTION
OF VSBY RESTRICTIONS OVRNGT DUE TO CLD CVR.
WINDS GENERALLY OUT OF THE SOUTH AT MOST TERMINALS TODAY ARND
03KTS EARLY IN TAF PERIOD INCREASING TO +06KTS THIS AFTERNOON.
OUTLOOK...
WED...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WED NGT-FRI AM...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY EACH MRNG.
FRI PM...MVFR IN SHOWERS/TSRA POSSIBLE.
SAT...VFR UNDER HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE/RRM
NEAR TERM...MSE/RRM
SHORT TERM...MSE
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1027 AM EDT TUE AUG 14 2012
.SYNOPSIS...
TODAY THROUGH WEDNESDAY, LOW PRESSURE WILL TRACK FROM THE OHIO
VALLEY NORTHEAST ACROSS WESTERN NEW YORK AND THEN INTO SOUTHERN
QUEBEC. THIS SYSTEM WILL BRING SHOWERS AND THUNDERSTORMS TO THE
AREA PRIMARILY THIS AFTERNOON AND EVENING. UNSETTLED WEATHER WILL
CONTINUE THROUGH WEDNESDAY BEFORE HIGH PRESSURE BRINGS DRY AND
SEASONAL CONDITIONS ON THURSDAY. ANOTHER COLD FRONT WILL BRING A
CHANCE FOR MORE SHOWERS AND THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
10 AM UPDATE...AREA OF SHOWERS AND ISOLATED THUNDERSTORMS NOW
DEPARTING THE WESTERN CATSKILLS AND POCONOS AS MID LEVEL SHORT
WAVE AND WEAK ISENTROPIC LIFT SHIFTS EAST. SATELLITE SHOWS
CLEARING SKIES ACROSS WESTERN NY AND INTO THE CENTRAL SOUTHERN
TIER. THIS AREA OF CLEARING IS EXPECTED TO MAKE PROGRESS ACROSS
THE FINGER LAKES REGION INTO THE LAKE PLAIN AND PARTS OF THE
SOUTHERN TIER. THIS WILL DESTABILIZE THE ATMOSPHERE PRIOR TO THE
NEXT MORE WIDESPREAD ROUND OF SHOWERS AND THUNDERSTORMS AS SFC LOW
TRACKS INTO WESTERN NEW YORK. CONVECTION WILL INCREASE LATER THIS
AFTERNOON INTO THE EVENING WITH STILL THE THREAT THAT A FEW MAY
BECOME SEVERE. JUST MINOR ADJUSTMENTS TO SHORT TERM POPS/CLOUDS/TEMPS.
.PREVIOUS DISC...
FIRST ROUND OF SHOWERS WILL BE PASSING OFF TO THE EAST
OF THE AREA BY EARLY AFTERNOON. KEY TO STORM REDEVELOPMENT AND ANY
SEVERE POTENTIAL WILL BE HOW MUCH CLEARING CAN OCCUR IN THE WAKE
OF THESE SHOWERS THROUGH MID- AFTERNOON... BEFORE ANOTHER WAVE
ROTATING AROUND THE UPPER TROUGH BRINGS ANOTHER ROUND OF
CONVECTION LATER THIS AFTERNOON INTO THIS EVENING. CURRENTLY SOME
CLEARING IS OCCURRING BEHIND THE INITIAL WAVE OVER OHIO... AND AT
THIS POINT EXPECT SOME OF THAT CLEARING TO WORK EAST ACROSS OUR
AREA THIS AFTERNOON. SREF CAPE FORECAST PLUMES INDICATE A WIDE
RANGE OF POSSIBLE CAPES THIS AFTERNOON... WITH MEAN VALUES NEAR
1000 J/KG. NAM/GFS AND RUC ALSO INDICATING NEAR 1000 J/KG POSSIBLE
THIS AFTERNOON. THE COMBINATION OF A WEAKLY UNSTABLE ENVIRONMENT
WITH DEEP LAYER BULK SHEAR VALUES OF 20 TO 30 KTS WILL BE ENOUGH
TO PROMOTE SOME ORGANIZED CONVECTION LATER THIS AFTERNOON INTO
THIS EVENING. HOWEVER STRONG FORCING FOR A WIDESPREAD SEVERE EVENT
APPEARS TO BE LACKING AS LOW-LEVEL CONVERGENCE WILL BE WEAK IN
ASSOCIATION WITH A WEAK... POORLY ORGANIZED SURFACE LOW... AND
MID-TO-UPPER LEVEL HEIGHT FALLS WILL ALSO BE MINIMAL. BASED ON ALL
OF THE ABOVE REASONING EXPECT A FEW STRONG TO MARGINALLY SEVERE
STORMS TO DEVELOP LATER THIS AFTERNOON WITH ISOLATED SEVERE
REPORTS LIKELY BUT NOT A WIDESPREAD EVENT. SPC HAS THE SOUTHERN
HALF OF OUR AREA IN A SLIGHT RISK OF SEVERE WEATHER TODAY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS IS TYPICAL FOR THIS TIME OF YEAR... SURFACE LOW PRESSURE AND
ASSOCIATED FRONTAL ZONES WILL BE SLOW TO MOVE EAST... AND THESE
FEATURES WILL LIKELY LINGER OVER THE AREA INTO WEDNESDAY. EXPECT
STORM COVERAGE TO DIMINISH LATER THIS EVENING... BUT A FEW STORMS
COULD LINGER THROUGH TONIGHT AS THE ATMOSPHERE REMAINS WEAKLY
UNSTABLE. NAM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT WEAK SURFACE
LOW PRESSURE WILL EVENTUALLY DEVELOP SOMEWHERE OVER SOUTHERN PA OR
NEW JERSEY ON WEDNESDAY WITH THE SUPPORTING UPPER TROUGH LINGERING
JUST TO THE WEST. THIS WILL KEEP THE CHANCE FOR SHOWERS AND
SCATTERED THUNDERSTORMS GOING THROUGH WEDNESDAY. BOTH THE
INSTABILITY AND SHEAR WILL BE LESS ON WEDNESDAY COMPARED TO TODAY
AND AS A RESULT THE SEVERE THREAT WILL BE LOWER. ACTUALLY WOULD
EXPECT THE THREAT FOR LOCALIZED HEAVY RAIN TO BE GREATER THAN THE
SEVERE THREAT ON WEDNESDAY GIVEN EXPECTED LIGHT WIND FIELDS ALOFT.
THE UPPER TROUGH FINALLY MOVES EAST OF THE AREA BY THURSDAY...
BRINGING A RETURN TO DRY SEASONABLY WARM WEATHER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
330 AM UPDATE...NO MAJOR CHGS NEEDED TO LONG TERM AT THIS TIME.
STILL SHOWING STRONG CDFNT EXPECTED TO PASS THRU FRIDAY WITH CHC
SHRAS/TSTMS. WUD NOT BE SURPRISED TO SEE POPS BOOSTED INTO THE
LKLY CATEGORY.
LONG TERM MODELS (BOTH GFS AND ECMWF) INDICATE UL TROFFING THRU
THE END OF THE PD WITH HUDSON BAY VORTEX HANGING ON THRU EARLY
NEXT WEEK. HIPRES BHND CDFNT BUILDING IN MAY LEAD TO CLRNG SKIES
SAT NGT INTO SUNDAY THO GNRLY CLOUDY AND COOLER CONDS WL BE THE
RULE AFT THE WEEKEND WITH UL TROF HANGING ON.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
630 AM UPDATE...
VFR CONDS THIS MORNING. AREA OF SHOWERS MOVING INTO KAVP TERMINAL
AT THIS TIME WITH LITTLE IN THE WAY OF MVFR RESTRICTIONS EXPECTED.
EXPECT PREDOMINANT SHOWERS TO LAST THROUGH 14Z THIS MORNING BEFORE
A BRIEF BREAK BEFORE AFTERNOON CONVECTION.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AFTER 18Z ACROSS
WESTERN AND NORTHERN TERMINALS. HAVE INCLUDED MENTION OF THUNDER
ACROSS ALL TERMINALS FROM 20Z TO 00Z THIS EVENING WITH LITTLE IN
THE WAY OF RESTRICTIONS.
BKN-OVC CIGS EXPECTED AFTER 00Z. CONDITIONS DO NOT WARRANT MENTION
OF VSBY RESTRICTIONS OVRNGT DUE TO CLD CVR.
WINDS GENERALLY OUT OF THE SOUTH AT MOST TERMINALS TODAY ARND
03KTS EARLY IN TAF PERIOD INCREASING TO +06KTS THIS AFTERNOON.
OUTLOOK...
WED...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WED NGT-FRI AM...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY EACH MRNG.
FRI PM...MVFR IN SHOWERS/TSRA POSSIBLE.
SAT...VFR UNDER HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE/RRM
NEAR TERM...MSE/RRM
SHORT TERM...MSE
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
653 AM EDT TUE AUG 14 2012
.SYNOPSIS...
A SLOW-MOVING FRONTAL SYSTEM WILL TRACK ACROSS THE AREA TODAY
THROUGH WEDNESDAY... ACCOMPANIED BY A FEW SHOWERS AND
THUNDERSTORMS. A WEAK RIDGE OF HIGH PRESSURE WILL BRING DRY WARM
WEATHER ON THURSDAY... THEN ANOTHER COLD FRONT WILL BRING A CHANCE
FOR MORE SHOWERS AND STORMS ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
.UPDATED AT 630 AM... HAVE UPDATED GRIDS BASED ON LATEST TRENDS.
AREA OF RAIN CONTINUES TO MOVE FROM CENTRAL TO NORTHEAST PA AND
HAVE INCREASED POPS TO 80 PERCENT OR GREATER TO COVER FOR THE
EXPECTED MOVEMENT OF THIS SYSTEM ACROSS NORTHEAST PA THROUGH ABOUT
9 AM. CONVECTIVE TREND WITH THIS SYSTEM HAS BEEN TOWARD WEAKENING
DURING THE PAST HOUR. DOPPLER RADAR ESTIMATES INDICATED OVER AN INCH
OF RAIN OVER A SMALL AREA WEST OF LUZERNE COUNTY... BUT RAIN RATES
AND LIGHTNING HAVE ALL DIMINISHED SINCE 5 AM. FARTHER NORTH RADAR
TRENDS INDICATE THAT JUST WIDELY SCATTERED SHOWERS OR STORMS CAN
BE EXPECTED THROUGH THE REST OF THIS MORNING. PREVIOUS DISCUSSION
BELOW.
AN UPPER LEVEL TROUGH IS GRADUALLY SETTLING IN ACROSS THE OHIO
VALLEY AND GREAT LAKES AREA THIS MORNING. THE FIRST IN A SERIES OF
SHORT WAVES IS TRACKING NORTHEAST AROUND THE EAST SIDE OF THE
TROUGH ACROSS THE CENTRAL APPALACHIANS EARLY THIS MORNING. THIS
WAVE IS ASSOCIATED WITH GRADUALLY COOLING CLOUD TOPS AND A WELL-
DEFINED AREA OF SHOWERS MOVING NORTHEAST ACROSS CENTRAL PA
AS OF 08Z. MEANWHILE... ANOTHER WAVE IS BRINGING A ROUND OF
SHOWERS TO THE LAKE PLAIN AREA OF UPSTATE NY SOUTH OF LAKE
ONTARIO. THESE SHOWERS WILL PASS ACROSS THE AREA THIS MORNING. AT
THIS POINT EXPECT ABOUT HALF OF OUR FORECAST AREA TO SEE SOME RAIN
THROUGH ABOUT 9 AM WITH THESE FEATURES... WITH THE BEST CHANCE
BEING ACROSS NORTHEAST PA AS SHOWERS PROGRESS NORTHEAST FROM
CENTRAL PA.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
FIRST ROUND OF SHOWERS WILL BE PASSING OFF TO THE EAST OF THE AREA
BY EARLY AFTERNOON. KEY TO STORM REDEVELOPMENT AND ANY SEVERE
POTENTIAL WILL BE HOW MUCH CLEARING CAN OCCUR IN THE WAKE OF THESE
SHOWERS THROUGH MID-AFTERNOON... BEFORE ANOTHER WAVE ROTATING
AROUND THE UPPER TROUGH BRINGS ANOTHER ROUND OF CONVECTION LATER
THIS AFTERNOON INTO THIS EVENING. CURRENTLY SOME CLEARING IS
OCCURRING BEHIND THE INITIAL WAVE OVER OHIO... AND AT THIS POINT
EXPECT SOME OF THAT CLEARING TO WORK EAST ACROSS OUR AREA THIS
AFTERNOON. SREF CAPE FORECAST PLUMES INDICATE A WIDE RANGE OF
POSSIBLE CAPES THIS AFTERNOON... WITH MEAN VALUES NEAR 1000 J/KG.
NAM/GFS AND RUC ALSO INDICATING NEAR 1000 J/KG POSSIBLE THIS
AFTERNOON. THE COMBINATION OF A WEAKLY UNSTABLE ENVIRONMENT WITH
DEEP LAYER BULK SHEAR VALUES OF 20 TO 30 KTS WILL BE ENOUGH TO
PROMOTE SOME ORGANIZED CONVECTION LATER THIS AFTERNOON INTO THIS EVENING.
HOWEVER STRONG FORCING FOR A WIDESPREAD SEVERE EVENT APPEARS TO BE
LACKING AS LOW-LEVEL CONVERGENCE WILL BE WEAK IN ASSOCIATION WITH
A WEAK... POORLY ORGANIZED SURFACE LOW... AND MID-TO-UPPER LEVEL
HEIGHT FALLS WILL ALSO BE MINIMAL. BASED ON ALL OF THE ABOVE REASONING
EXPECT A FEW STRONG TO MARGINALLY SEVERE STORMS TO DEVELOP LATER
THIS AFTERNOON WITH ISOLATED SEVERE REPORTS LIKELY BUT NOT A
WIDESPREAD EVENT. SPC HAS THE SOUTHERN HALF OF OUR AREA IN A
SLIGHT RISK OF SEVERE WEATHER TODAY.
AS IS TYPICAL FOR THIS TIME OF YEAR... SURFACE LOW PRESSURE AND
ASSOCIATED FRONTAL ZONES WILL BE SLOW TO MOVE EAST... AND THESE
FEATURES WILL LIKELY LINGER OVER THE AREA INTO WEDNESDAY. EXPECT
STORM COVERAGE TO DIMINISH LATER THIS EVENING... BUT A FEW STORMS
COULD LINGER THROUGH TONIGHT AS THE ATMOSPHERE REMAINS WEAKLY
UNSTABLE. NAM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT WEAK SURFACE
LOW PRESSURE WILL EVENTUALLY DEVELOP SOMEWHERE OVER SOUTHERN PA OR
NEW JERSEY ON WEDNESDAY WITH THE SUPPORTING UPPER TROUGH LINGERING
JUST TO THE WEST. THIS WILL KEEP THE CHANCE FOR SHOWERS AND
SCATTERED THUNDERSTORMS GOING THROUGH WEDNESDAY. BOTH THE
INSTABILITY AND SHEAR WILL BE LESS ON WEDNESDAY COMPARED TO TODAY
AND AS A RESULT THE SEVERE THREAT WILL BE LOWER. ACTUALLY WOULD
EXPECT THE THREAT FOR LOCALIZED HEAVY RAIN TO BE GREATER THAN THE
SEVERE THREAT ON WEDNESDAY GIVEN EXPECTED LIGHT WIND FIELDS ALOFT.
THE UPPER TROUGH FINALLY MOVES EAST OF THE AREA BY THURSDAY...
BRINGING A RETURN TO DRY SEASONABLY WARM WEATHER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
330 AM UPDATE...NO MAJOR CHGS NEEDED TO LONG TERM AT THIS TIME.
STILL SHOWING STRONG CDFNT EXPECTED TO PASS THRU FRIDAY WITH CHC
SHRAS/TSTMS. WUD NOT BE SURPRISED TO SEE POPS BOOSTED INTO THE
LKLY CATEGORY.
LONG TERM MODELS (BOTH GFS AND ECMWF) INDICATE UL TROFFING THRU
THE END OF THE PD WITH HUDSON BAY VORTEX HANGING ON THRU EARLY
NEXT WEEK. HIPRES BHND CDFNT BUILDING IN MAY LEAD TO CLRNG SKIES
SAT NGT INTO SUNDAY THO GNRLY CLOUDY AND COOLER CONDS WL BE THE
RULE AFT THE WEEKEND WITH UL TROF HANGING ON.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
630 AM UPDATE...
VFR CONDS THIS MORNING. AREA OF SHOWERS MOVING INTO KAVP TERMINAL
AT THIS TIME WITH LITTLE IN THE WAY OF MVFR RESTRICTIONS EXPECTED.
EXPECT PREDOMINANT SHOWERS TO LAST THROUGH 14Z THIS MORNING BEFORE
A BRIEF BREAK BEFORE AFTERNOON CONVECTION.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AFTER 18Z ACROSS
WESTERN AND NORTHERN TERMINALS. HAVE INCLUDED MENTION OF THUNDER
ACROSS ALL TERMINALS FROM 20Z TO 00Z THIS EVENING WITH LITTLE IN
THE WAY OF RESTRICTIONS.
BKN-OVC CIGS EXPECTED AFTER 00Z. CONDITIONS DO NOT WARRANT MENTION
OF VSBY RESTRICTIONS OVRNGT DUE TO CLD CVR.
WINDS GENERALLY OUT OF THE SOUTH AT MOST TERMINALS TODAY ARND
03KTS EARLY IN TAF PERIOD INCREASING TO +06KTS THIS AFTERNOON.
OUTLOOK...
WED...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WED NGT-FRI AM...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY EACH MRNG.
FRI PM...MVFR IN SHOWERS/TSRA POSSIBLE.
SAT...VFR UNDER HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE
SHORT TERM...MSE
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
644 AM EDT TUE AUG 14 2012
.SYNOPSIS...
A SLOW-MOVING FRONTAL SYSTEM WILL TRACK ACROSS THE AREA TODAY
THROUGH WEDNESDAY... ACCOMPANIED BY A FEW SHOWERS AND
THUNDERSTORMS. A WEAK RIDGE OF HIGH PRESSURE WILL BRING DRY WARM
WEATHER ON THURSDAY... THEN ANOTHER COLD FRONT WILL BRING A CHANCE
FOR MORE SHOWERS AND STORMS ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
.UPDATED AT 630 AM... HAVE UPDATED GRIDS BASED ON LATEST TRENDS.
AREA OF RAIN CONTINUES TO MOVE FROM CENTRAL TO NORTHEAST PA AND
HAVE INCREASED POPS TO 80 PERCENT OR GREATER TO COVER FOR THE
EXPECTED MOVEMENT OF THIS SYSTEM ACROSS NORTHEAST PA THROUGH ABOUT
9 AM. CONVECTIVE TREND WITH THIS SYSTEM HAS BEEN TOWARD WEAKENING
DURING THE PAST HOUR. DOPPLER RADAR ESTIMATES INDICATED OVER AN INCH
OF RAIN OVER A SMALL AREA WEST OF LUZERNE COUNTY... BUT RAIN RATES
AND LIGHTNING HAVE ALL DIMINISHED SINCE 5 AM. FARTHER NORTH RADAR
TRENDS INDICATE THAT JUST WIDELY SCATTERED SHOWERS OR STORMS CAN
BE EXPECTED THROUGH THE REST OF THIS MORNING. PREVIOUS DISCUSSION
BELOW.
AN UPPER LEVEL TROUGH IS GRADUALLY SETTLING IN ACROSS THE OHIO
VALLEY AND GREAT LAKES AREA THIS MORNING. THE FIRST IN A SERIES OF
SHORT WAVES IS TRACKING NORTHEAST AROUND THE EAST SIDE OF THE
TROUGH ACROSS THE CENTRAL APPALACHIANS EARLY THIS MORNING. THIS
WAVE IS ASSOCIATED WITH GRADUALLY COOLING CLOUD TOPS AND A WELL-
DEFINED AREA OF SHOWERS MOVING NORTHEAST ACROSS CENTRAL PA
AS OF 08Z. MEANWHILE... ANOTHER WAVE IS BRINGING A ROUND OF
SHOWERS TO THE LAKE PLANE AREA OF UPSTATE NY SOUTH OF LAKE
ONTARIO. THESE SHOWERS WILL PASS ACROSS THE AREA THIS MORNING. AT
THIS POINT EXPECT ABOUT HALF OF OUR FORECAST AREA TO SEE SOME RAIN
THROUGH ABOUT 9 AM WITH THESE FEATURES... WITH THE BEST CHANCE
BEING ACROSS NORTHEAST PA AS SHOWERS PROGRESS NORTHEAST FROM
CENTRAL PA.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
FIRST ROUND OF SHOWERS WILL BE PASSING OFF TO THE EAST OF THE AREA
BY EARLY AFTERNOON. KEY TO STORM REDEVELOPMENT AND ANY SEVERE
POTENTIAL WILL BE HOW MUCH CLEARING CAN OCCUR IN THE WAKE OF THESE
SHOWERS THROUGH MID-AFTERNOON... BEFORE ANOTHER WAVE ROTATING
AROUND THE UPPER TROUGH BRINGS ANOTHER ROUND OF CONVECTION LATER
THIS AFTERNOON INTO THIS EVENING. CURRENTLY SOME CLEARING IS
OCCURRING BEHIND THE INITIAL WAVE OVER OHIO... AND AT THIS POINT
EXPECT SOME OF THAT CLEARING TO WORK EAST ACROSS OUR AREA THIS
AFTERNOON. SREF CAPE FORECAST PLUMES INDICATE A WIDE RANGE OF
POSSIBLE CAPES THIS AFTERNOON... WITH MEAN VALUES NEAR 1000 J/KG.
NAM/GFS AND RUC ALSO INDICATING NEAR 1000 J/KG POSSIBLE THIS
AFTERNOON. THE COMBINATION OF A WEAKLY UNSTABLE ENVIRONMENT WITH
DEEP LAYER BULK SHEAR VALUES OF 20 TO 30 KTS WILL BE ENOUGH TO
PROMOTE SOME ORGANIZED CONVECTION LATER THIS AFTERNOON INTO THIS EVENING.
HOWEVER STRONG FORCING FOR A WIDESPREAD SEVERE EVENT APPEARS TO BE
LACKING AS LOW-LEVEL CONVERGENCE WILL BE WEAK IN ASSOCIATION WITH
A WEAK... POORLY ORGANIZED SURFACE LOW... AND MID-TO-UPPER LEVEL
HEIGHT FALLS WILL ALSO BE MINIMAL. BASED ON ALL OF THE ABOVE REASONING
EXPECT A FEW STRONG TO MARGINALLY SEVERE STORMS TO DEVELOP LATER
THIS AFTERNOON WITH ISOLATED SEVERE REPORTS LIKELY BUT NOT A
WIDESPREAD EVENT. SPC HAS THE SOUTHERN HALF OF OUR AREA IN A
SLIGHT RISK OF SEVERE WEATHER TODAY.
AS IS TYPICAL FOR THIS TIME OF YEAR... SURFACE LOW PRESSURE AND
ASSOCIATED FRONTAL ZONES WILL BE SLOW TO MOVE EAST... AND THESE
FEATURES WILL LIKELY LINGER OVER THE AREA INTO WEDNESDAY. EXPECT
STORM COVERAGE TO DIMINISH LATER THIS EVENING... BUT A FEW STORMS
COULD LINGER THROUGH TONIGHT AS THE ATMOSPHERE REMAINS WEAKLY
UNSTABLE. NAM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT WEAK SURFACE
LOW PRESSURE WILL EVENTUALLY DEVELOP SOMEWHERE OVER SOUTHERN PA OR
NEW JERSEY ON WEDNESDAY WITH THE SUPPORTING UPPER TROUGH LINGERING
JUST TO THE WEST. THIS WILL KEEP THE CHANCE FOR SHOWERS AND
SCATTERED THUNDERSTORMS GOING THROUGH WEDNESDAY. BOTH THE
INSTABILITY AND SHEAR WILL BE LESS ON WEDNESDAY COMPARED TO TODAY
AND AS A RESULT THE SEVERE THREAT WILL BE LOWER. ACTUALLY WOULD
EXPECT THE THREAT FOR LOCALIZED HEAVY RAIN TO BE GREATER THAN THE
SEVERE THREAT ON WEDNESDAY GIVEN EXPECTED LIGHT WIND FIELDS ALOFT.
THE UPPER TROUGH FINALLY MOVES EAST OF THE AREA BY THURSDAY...
BRINGING A RETURN TO DRY SEASONABLY WARM WEATHER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
330 AM UPDATE...NO MAJOR CHGS NEEDED TO LONG TERM AT THIS TIME.
STILL SHOWING STRONG CDFNT EXPECTED TO PASS THRU FRIDAY WITH CHC
SHRAS/TSTMS. WUD NOT BE SURPRISED TO SEE POPS BOOSTED INTO THE
LKLY CATEGORY.
LONG TERM MODELS (BOTH GFS AND ECMWF) INDICATE UL TROFFING THRU
THE END OF THE PD WITH HUDSON BAY VORTEX HANGING ON THRU EARLY
NEXT WEEK. HIPRES BHND CDFNT BUILDING IN MAY LEAD TO CLRNG SKIES
SAT NGT INTO SUNDAY THO GNRLY CLOUDY AND COOLER CONDS WL BE THE
RULE AFT THE WEEKEND WITH UL TROF HANGING ON.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
630 AM UPDATE...
VFR CONDS THIS MORNING. AREA OF SHOWERS MOVING INTO KAVP TERMINAL
AT THIS TIME WITH LITTLE IN THE WAY OF MVFR RESTRICTIONS EXPECTED.
EXPECT PREDOMINANT SHOWERS TO LAST THROUGH 14Z THIS MORNING BEFORE
A BRIEF BREAK BEFORE AFTERNOON CONVECTION.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AFTER 18Z ACROSS
WESTERN AND NORTHERN TERMINALS. HAVE INCLUDED MENTION OF THUNDER
ACROSS ALL TERMINALS FROM 20Z TO 00Z THIS EVENING WITH LITTLE IN
THE WAY OF RESTRICTIONS.
BKN-OVC CIGS EXPECTED AFTER 00Z. CONDITIONS DO NOT WARRANT MENTION
OF VSBY RESTRICTIONS OVRNGT DUE TO CLD CVR.
WINDS GENERALLY OUT OF THE SOUTH AT MOST TERMINALS TODAY ARND
03KTS EARLY IN TAF PERIOD INCREASING TO +06KTS THIS AFTERNOON.
OUTLOOK...
WED...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WED NGT-FRI AM...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY EACH MRNG.
FRI PM...MVFR IN SHOWERS/TSRA POSSIBLE.
SAT...VFR UNDER HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE
SHORT TERM...MSE
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
638 AM EDT TUE AUG 14 2012
.SYNOPSIS...
A SLOW-MOVING FRONTAL SYSTEM WILL TRACK ACROSS THE AREA TODAY
THROUGH WEDNESDAY... ACCOMPANIED BY A FEW SHOWERS AND
THUNDERSTORMS. A WEAK RIDGE OF HIGH PRESSURE WILL BRING DRY WARM
WEATHER ON THURSDAY... THEN ANOTHER COLD FRONT WILL BRING A CHANCE
FOR MORE SHOWERS AND STORMS ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
.UPDATED AT 630 AM... HAVE UPDATED GRIDS BASED ON LATEST TRENDS.
AREA OF RAIN CONTINUES TO MOVE FROM CENTRAL TO NORTHEAST PA AND
HAVE INCREASED POPS TO 80 PERCENT OR GREATER TO COVER FOR THE
EXPECTED MOVEMENT OF THIS SYSTEM ACROSS NORTHEAST PA THROUGH ABOUT
9 AM. CONVECTIVE TREND WITH THIS SYSTEM HAS BEEN TOWARD WEAKENING
DURING THE PAST HOUR. DOPPLER RADAR ESTIMATES INDICATED OVER AN INCH
OF RAIN OVER A SMALL AREA WEST OF LUZERNE COUNTY... BUT RAIN RATES
AND LIGHTNING HAVE ALL DIMINISHED SINCE 5 AM. FARTHER NORTH RADAR
TRENDS INDICATE THAT JUST WIDELY SCATTERED SHOWERS OR STORMS CAN
BE EXPECTED THROUGH THE REST OF THIS MORNING. PREVIOUS DISCUSSION
BELOW.
AN UPPER LEVEL TROUGH IS GRADUALLY SETTLING IN ACROSS THE OHIO
VALLEY AND GREAT LAKES AREA THIS MORNING. THE FIRST IN A SERIES OF
SHORT WAVES IS TRACKING NORTHEAST AROUND THE EAST SIDE OF THE
TROUGH ACROSS THE CENTRAL APPALACHIANS EARLY THIS MORNING. THIS
WAVE IS ASSOCIATED WITH GRADUALLY COOLING CLOUD TOPS AND A WELL-
DEFINED AREA OF SHOWERS MOVING NORTHEAST ACROSS CENTRAL PA
AS OF 08Z. MEANWHILE... ANOTHER WAVE IS BRINGING A ROUND OF
SHOWERS TO THE LAKE PLANE AREA OF UPSTATE NY SOUTH OF LAKE
ONTARIO. THESE SHOWERS WILL PASS ACROSS THE AREA THIS MORNING. AT
THIS POINT EXPECT ABOUT HALF OF OUR FORECAST AREA TO SEE SOME RAIN
THROUGH ABOUT 9 AM WITH THESE FEATURES... WITH THE BEST CHANCE
BEING ACROSS NORTHEAST PA AS SHOWERS PROGRESS NORTHEAST FROM
CENTRAL PA.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
FIRST ROUND OF SHOWERS WILL BE PASSING OFF TO THE EAST OF THE AREA
BY EARLY AFTERNOON. KEY TO STORM REDEVELOPMENT AND ANY SEVERE
POTENTIAL WILL BE HOW MUCH CLEARING CAN OCCUR IN THE WAKE OF THESE
SHOWERS THROUGH MID-AFTERNOON... BEFORE ANOTHER WAVE ROTATING
AROUND THE UPPER TROUGH BRINGS ANOTHER ROUND OF CONVECTION LATER
THIS AFTERNOON INTO THIS EVENING. CURRENTLY SOME CLEARING IS
OCCURRING BEHIND THE INITIAL WAVE OVER OHIO... AND AT THIS POINT
EXPECT SOME OF THAT CLEARING TO WORK EAST ACROSS OUR AREA THIS
AFTERNOON. SREF CAPE FORECAST PLUMES INDICATE A WIDE RANGE OF
POSSIBLE CAPES THIS AFTERNOON... WITH MEAN VALUES NEAR 1000 J/KG.
NAM/GFS AND RUC ALSO INDICATING NEAR 1000 J/KG POSSIBLE THIS
AFTERNOON. THE COMBINATION OF A WEAKLY UNSTABLE ENVIRONMENT WITH
DEEP LAYER BULK SHEAR VALUES OF 20 TO 30 KTS WILL BE ENOUGH TO
PROMOTE SOME ORGANIZED CONVECTION LATER THIS AFTERNOON INTO THIS EVENING.
HOWEVER STRONG FORCING FOR A WIDESPREAD SEVERE EVENT APPEARS TO BE
LACKING AS LOW-LEVEL CONVERGENCE WILL BE WEAK IN ASSOCIATION WITH
A WEAK... POORLY ORGANIZED SURFACE LOW... AND MID-TO-UPPER LEVEL
HEIGHT FALLS WILL ALSO BE MINIMAL. BASED ON ALL OF THE ABOVE REASONING
EXPECT A FEW STRONG TO MARGINALLY SEVERE STORMS TO DEVELOP LATER
THIS AFTERNOON WITH ISOLATED SEVERE REPORTS LIKELY BUT NOT A
WIDESPREAD EVENT. SPC HAS THE SOUTHERN HALF OF OUR AREA IN A
SLIGHT RISK OF SEVERE WEATHER TODAY.
AS IS TYPICAL FOR THIS TIME OF YEAR... SURFACE LOW PRESSURE AND
ASSOCIATED FRONTAL ZONES WILL BE SLOW TO MOVE EAST... AND THESE
FEATURES WILL LIKELY LINGER OVER THE AREA INTO WEDNESDAY. EXPECT
STORM COVERAGE TO DIMINISH LATER THIS EVENING... BUT A FEW STORMS
COULD LINGER THROUGH TONIGHT AS THE ATMOSPHERE REMAINS WEAKLY
UNSTABLE. NAM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT WEAK SURFACE
LOW PRESSURE WILL EVENTUALLY DEVELOP SOMEWHERE OVER SOUTHERN PA OR
NEW JERSEY ON WEDNESDAY WITH THE SUPPORTING UPPER TROUGH LINGERING
JUST TO THE WEST. THIS WILL KEEP THE CHANCE FOR SHOWERS AND
SCATTERED THUNDERSTORMS GOING THROUGH WEDNESDAY. BOTH THE
INSTABILITY AND SHEAR WILL BE LESS ON WEDNESDAY COMPARED TO TODAY
AND AS A RESULT THE SEVERE THREAT WILL BE LOWER. ACTUALLY WOULD
EXPECT THE THREAT FOR LOCALIZED HEAVY RAIN TO BE GREATER THAN THE
SEVERE THREAT ON WEDNESDAY GIVEN EXPECTED LIGHT WIND FIELDS ALOFT.
THE UPPER TROUGH FINALLY MOVES EAST OF THE AREA BY THURSDAY...
BRINGING A RETURN TO DRY SEASONABLY WARM WEATHER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
330 AM UPDATE...NO MAJOR CHGS NEEDED TO LONG TERM AT THIS TIME.
STILL SHOWING STRONG CDFNT EXPECTED TO PASS THRU FRIDAY WITH CHC
SHRAS/TSTMS. WUD NOT BE SURPRISED TO SEE POPS BOOSTED INTO THE
LKLY CATEGORY.
LONG TERM MODELS (BOTH GFS AND ECMWF) INDICATE UL TROFFING THRU
THE END OF THE PD WITH HUDSON BAY VORTEX HANGING ON THRU EARLY
NEXT WEEK. HIPRES BHND CDFNT BUILDING IN MAY LEAD TO CLRNG SKIES
SAT NGT INTO SUNDAY THO GNRLY CLOUDY AND COOLER CONDS WL BE THE
RULE AFT THE WEEKEND WITH UL TROF HANGING ON.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
130 AM UPDATE...
VFR CONDS EXPECTED AT ALL TERMINALS WITH EXCEPTION OF KELM EARLY
THIS MORNING. BKN-OVC100 CIGS ACRS KSYR/KRME WITH SKC FURTHER
SOUTH. AREA OF LIGHT SHOWERS MOVING ACROSS WESTERN NY AT THIS
MOMENT MAY MAKE IT INTO TERMINALS THIS MORNING BUT CONFIDENCE NOT
HIGH ENOUGH TO MENTION IN TERMINAL FORECASTS. HOWEVER GROWING AREA
OF RAIN ACROSS SOUTHERN PA MAY IMPACT KAVP BTWN 12Z-14Z AND HAVE
THROWN IN TEMPO MENTION TO THIS TERMINAL.
WITH CLEAR SKIES AND LIGHT WINDS AT KELM...MAY SEE BRIEF MVFR VSBY
RESTRICTIONS THROUGH 09Z BEFORE OVC DECK MOVES IN. BY AFTERNOON
EXPECT -SHRA TO DEVELOP ALL TERMINALS AFTER 18Z WITH SOME TSTMS
EXPECTED...HOWEVER CONFIDENCE REMAINS LOW ON TIMING AND SPECIFIC
TERMINALS TO BE IMPACTED.
WINDS GENERALLY OUT OF THE SOUTH AT MOST TERMINALS TODAY ARND
03KTS EARLY IN TAF PERIOD INCREASING TO +06KTS THIS AFTERNOON.
OUTLOOK...
WED...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WED NGT-FRI AM...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY EACH MRNG.
FRI PM...MVFR IN SHOWERS/TSRA POSSIBLE.
SAT...VFR UNDER HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE
SHORT TERM...MSE
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
415 AM EDT TUE AUG 14 2012
.SYNOPSIS...
A SLOW-MOVING FRONTAL SYSTEM WILL TRACK ACROSS THE AREA TODAY
THROUGH WEDNESDAY... ACCOMPANIED BY A FEW SHOWERS AND
THUNDERSTORMS. A WEAK RIDGE OF HIGH PRESSURE WILL BRING DRY WARM
WEATHER ON THURSDAY... THEN ANOTHER COLD FRONT WILL BRING A CHANCE
FOR MORE SHOWERS AND STORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 11 AM THIS MORNING/...
AN UPPER LEVEL TROUGH IS GRADUALLY SETTLING IN ACROSS THE OHIO
VALLEY AND GREAT LAKES AREA THIS MORNING. THE FIRST IN A SERIES OF
SHORT WAVES IS TRACKING NORTHEAST AROUND THE EAST SIDE OF THE
TROUGH ACROSS THE CENTRAL APPALACHIANS EARLY THIS MORNING. THIS
WAVE IS ASSOCIATED WITH GRADUALLY COOLING CLOUD TOPS AND A WELL-
DEFINED AREA OF SHOWERS MOVING NORTHEAST ACROSS CENTRAL PA
AS OF 08Z. MEANWHILE... ANOTHER WAVE IS BRINGING A ROUND OF
SHOWERS TO THE LAKE PLANE AREA OF UPSTATE NY SOUTH OF LAKE
ONTARIO. THESE SHOWERS WILL PASS ACROSS THE AREA THIS MORNING. AT
THIS POINT EXPECT ABOUT HALF OF OUR FORECAST AREA TO SEE SOME RAIN
THROUGH ABOUT 9 AM WITH THESE FEATURES... WITH THE BEST CHANCE
BEING ACROSS NORTHEAST PA AS SHOWERS PROGRESS NORTHEAST FROM
CENTRAL PA.
&&
.SHORT TERM /11 AM THIS MORNING THROUGH THURSDAY/...
FIRST ROUND OF SHOWERS WILL BE PASSING OFF TO THE EAST OF THE AREA
BY EARLY AFTERNOON. KEY TO STORM REDEVELOPMENT AND ANY SEVERE
POTENTIAL WILL BE HOW MUCH CLEARING CAN OCCUR IN THE WAKE OF THESE
SHOWERS THROUGH MID-AFTERNOON... BEFORE ANOTHER WAVE ROTATING
AROUND THE UPPER TROUGH BRINGS ANOTHER ROUND OF CONVECTION LATER
THIS AFTERNOON INTO THIS EVENING. CURRENTLY SOME CLEARING IS
OCCURRING BEHIND THE INITIAL WAVE OVER OHIO... AND AT THIS POINT
EXPECT SOME OF THAT CLEARING TO WORK EAST ACROSS OUR AREA THIS
AFTERNOON. SREF CAPE FORECAST PLUMES INDICATE A WIDE RANGE OF
POSSIBLE CAPES THIS AFTERNOON... WITH MEAN VALUES NEAR 1000 J/KG.
NAM/GFS AND RUC ALSO INDICATING NEAR 1000 J/KG POSSIBLE THIS
AFTERNOON. THE COMBINATION OF A WEAKLY UNSTABLE ENVIRONMENT WITH
DEEP LAYER BULK SHEAR VALUES OF 20 TO 30 KTS WILL BE ENOUGH TO
PROMOTE SOME ORGANIZED CONVECTION LATER THIS AFTERNOON INTO THIS EVENING.
HOWEVER STRONG FORCING FOR A WIDESPREAD SEVERE EVENT APPEARS TO BE
LACKING AS LOW-LEVEL CONVERGENCE WILL BE WEAK IN ASSOCIATION WITH
A WEAK... POORLY ORGANIZED SURFACE LOW... AND MID-TO-UPPER LEVEL
HEIGHT FALLS WILL ALSO BE MINIMAL. BASED ON ALL OF THE ABOVE REASONING
EXPECT A FEW STRONG TO MARGINALLY SEVERE STORMS TO DEVELOP LATER
THIS AFTERNOON WITH ISOLATED SEVERE REPORTS LIKELY BUT NOT A
WIDESPREAD EVENT. SPC HAS THE SOUTHERN HALF OF OUR AREA IN A
SLIGHT RISK OF SEVERE WEATHER TODAY.
AS IS TYPICAL FOR THIS TIME OF YEAR... SURFACE LOW PRESSURE AND
ASSOCIATED FRONTAL ZONES WILL BE SLOW TO MOVE EAST... AND THESE
FEATURES WILL LIKELY LINGER OVER THE AREA INTO WEDNESDAY. EXPECT
STORM COVERAGE TO DIMINISH LATER THIS EVENING... BUT A FEW STORMS
COULD LINGER THROUGH TONIGHT AS THE ATMOSPHERE REMAINS WEAKLY
UNSTABLE. NAM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT WEAK SURFACE
LOW PRESSURE WILL EVENTUALLY DEVELOP SOMEWHERE OVER SOUTHERN PA OR
NEW JERSEY ON WEDNESDAY WITH THE SUPPORTING UPPER TROUGH LINGERING
JUST TO THE WEST. THIS WILL KEEP THE CHANCE FOR SHOWERS AND
SCATTERED THUNDERSTORMS GOING THROUGH WEDNESDAY. BOTH THE
INSTABILITY AND SHEAR WILL BE LESS ON WEDNESDAY COMPARED TO TODAY
AND AS A RESULT THE SEVERE THREAT WILL BE LOWER. ACTUALLY WOULD
EXPECT THE THREAT FOR LOCALIZED HEAVY RAIN TO BE GREATER THAN THE
SEVERE THREAT ON WEDNESDAY GIVEN EXPECTED LIGHT WIND FIELDS ALOFT.
THE UPPER TROUGH FINALLY MOVES EAST OF THE AREA BY THURSDAY...
BRINGING A RETURN TO DRY SEASONABLY WARM WEATHER.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
330 AM UPDATE...NO MAJOR CHGS NEEDED TO LONG TERM AT THIS TIME.
STILL SHOWING STRONG CDFNT EXPECTED TO PASS THRU FRIDAY WITH CHC
SHRAS/TSTMS. WUD NOT BE SURPRISED TO SEE POPS BOOSTED INTO THE
LKLY CATEGORY.
LONG TERM MODELS (BOTH GFS AND ECMWF) INDICATE UL TROFFING THRU
THE END OF THE PD WITH HUDSON BAY VORTEX HANGING ON THRU EARLY
NEXT WEEK. HIPRES BHND CDFNT BUILDING IN MAY LEAD TO CLRNG SKIES
SAT NGT INTO SUNDAY THO GNRLY CLOUDY AND COOLER CONDS WL BE THE
RULE AFT THE WEEKEND WITH UL TROF HANGING ON.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
130 AM UPDATE...
VFR CONDS EXPECTED AT ALL TERMINALS WITH EXCEPTION OF KELM EARLY
THIS MORNING. BKN-OVC100 CIGS ACRS KSYR/KRME WITH SKC FURTHER
SOUTH. AREA OF LIGHT SHOWERS MOVING ACROSS WESTERN NY AT THIS
MOMENT MAY MAKE IT INTO TERMINALS THIS MORNING BUT CONFIDENCE NOT
HIGH ENOUGH TO MENTION IN TERMINAL FORECASTS. HOWEVER GROWING AREA
OF RAIN ACROSS SOUTHERN PA MAY IMPACT KAVP BTWN 12Z-14Z AND HAVE
THROWN IN TEMPO MENTION TO THIS TERMINAL.
WITH CLEAR SKIES AND LIGHT WINDS AT KELM...MAY SEE BRIEF MVFR VSBY
RESTRICTIONS THROUGH 09Z BEFORE OVC DECK MOVES IN. BY AFTERNOON
EXPECT -SHRA TO DEVELOP ALL TERMINALS AFTER 18Z WITH SOME TSTMS
EXPECTED...HOWEVER CONFIDENCE REMAINS LOW ON TIMING AND SPECIFIC
TERMINALS TO BE IMPACTED.
WINDS GENERALLY OUT OF THE SOUTH AT MOST TERMINALS TODAY ARND
03KTS EARLY IN TAF PERIOD INCREASING TO +06KTS THIS AFTERNOON.
OUTLOOK...
WED...OCCASIONAL MVFR IN SCATTERED CONVECTION.
WED NGT-FRI AM...MAINLY VFR EXCEPT FOR VALLEY FOG EARLY EACH MRNG.
FRI PM...MVFR IN SHOWERS/TSRA POSSIBLE.
SAT...VFR UNDER HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE
SHORT TERM...MSE
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
935 AM CDT TUE AUG 14 2012
.DISCUSSION...
UPDATED TO INCREASE CLOUD COVER A LITTLE ACROSS THE SOUTH THRU THE
MORNING. MAIN CHALLENGE IS HOW FAST THESE CLOUDS SHIFT OFF TO THE
EAST. WILL LOWER TEMPS A FEW DEGREES IN THE SOUTH BUT THINK IT
SHOULD SCATTER OUT LATER AND ALLOW TEMPS TO REBOUND QUICKLY.
EXPANDED THE MENTION OF SPRINKLES A LITTLE FURTHER TO THE EAST AS
WELL.
&&
.AVIATION...
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AS MID AND UPPER
LEVEL CLOUDS INCREASE. LIGHT WINDS WILL INCREASE OUT OF THE
SOUTHEAST AFTER 18Z AS LOW PRESSURE DEVELOPS TO THE WEST.
&&
.PREV DISCUSSION... /ISSUED 354 AM CDT TUE AUG 14 2012/
SHORT TERM...
PRECIP CHANCE FOR TONIGHT AND TOMORROW AND TEMPERATURES THURSDAY
WILL BE THE PRIMARY FORECAST CHALLENGES FOR THE PERIOD.
WV LOOP AND UPPER AIR ANALYSIS SHOW NORTHWESTERLY FLOW ALOFT WITH
SIGNS OF AN EMBEDDED WEAK SHORTWAVE OVER THE NORTHERN PLAINS...BUT
THE MAIN UPPER SYSTEM IS STILL DIGGING INTO BRITISH COLUMBIA. THE
THE NAM AND RAP ALONG WITH THE HRRR HAVE SOME LIGHT PRECIP
ENTERING OUR CWA THIS MORNING AS THE WEAK SHORTWAVE MOVES
THROUGH...WHILE THE LARGER SCALE MODELS STAY DRY. THERE HAS BEEN
SOME RADAR RETURNS OVER BIS...BUT THEY HAVE PRODUCED ONLY A VERY
SMALL AMOUNT OF RAIN AND SEEM TO BE ON A DOWNWARD TREND. WILL
MONITOR THROUGH THE NEXT HOUR OR SO IN CASE SOME SPRINKLES NEED TO
BE ADDED TO THE SOUTHWESTERN CWA THIS MORNING...BUT DO NOT THINK
WE WILL SEE ANYTHING MEASURABLE.
HIGH PRESSURE WILL MOVE OFF TO THE EAST TODAY...WITH SOUTHERLY
WINDS STARTING TO PICK UP OVER THE WESTERN CWA AS THE SFC LOW
DEVELOPS OVER EASTERN MT. HIGHS SHOULD BE A BIT WARMER THAN
YESTERDAY. TONIGHT...THE UPPER TROUGH WILL BEGIN TO DIG INTO MT
FROM CANADA...WHICH SHOULD HELP PUSH THE SFC LOW OUT INTO THE
PLAINS. THERE ARE SOME VARIATIONS AS TO HOW MUCH PRECIP BREAKS OUT
TONIGHT IN THE WARM AIR ADVECTION ON THE FRONT SIDE OF THE SYSTEM.
NAM AND GFS ARE IN FAIRLY DECENT AGREEMENT ON SOME DEVELOPMENT
OVER THE SOUTHERN COUNTIES OVERNIGHT...SO CONCENTRATED THE HIGHEST
POPS IN THAT AREA THIS EVENING WITH HIGHS POPS AFTER MIDNIGHT AS
THE SYSTEM CONTINUES TO MOVE CLOSER.
THE UPPER TROUGH WILL DIG INTO THE DAKOTAS ON WEDNESDAY...AND MUCH
DEPENDS ON THE EXACT TIMING OF THE UPPER SYSTEM AND ASSOCIATED
COLD FRONT...AND THE MODELS CONTINUE TO STRUGGLE WITH THIS. THE
NAM IS NOW SLOWER THAN THE GFS...WITH THE FRONT THROUGH MOST OF
THE COUNTIES BY MID DAY BUT IT SHOULD REACH THE SOUTHEAST BY PEAK
HEATING AND THE NAM SHOWS SOME DECENT INSTABILITY. THE GFS IS
FASTER AND HAS THE FRONT THROUGH ALL BUT THE FAR EASTERN EDGE BY
00Z THURSDAY. MEANWHILE...THE ECMWF IS SLOWER WITH THE UPPER
SYSTEM AND CONTINUES TO SHOW LINGERING PRECIP OVER THE EASTERN
COUNTIES THROUGH EARLY THURSDAY MORNING. ECMWF SEEMS TO HAVE MORE
INTERNAL CONSISTENCY...WITH THE NAM AND GFS DOING A LOT OF FLIP
FLOPPING. STILL A LOT OF UNCERTAINTY AS TO THE TIMING. IN THE
INTERESTS OF INTERSITE CONSISTENCY...CONTINUED TO KEEP LIKELY POPS
IN THE EASTERN COUNTIES FOR WEDNESDAY AFTERNOON AND EVENING WITH
SOME EVEN LINGERING AFTER MIDNIGHT IN THE FAR EASTERN COUNTIES.
AFTER THE COLD FRONT MOVES THROUGH...850MB TEMPS WILL BE IN THE
SINGLE DIGITS C AND WITH THE COLD POOL ALOFT...THERE WILL BE A
FAIR AMOUNT OF CLOUDS LINGERING AND EVEN SOME SHOWERS IN THE
NORTHEASTERN COUNTIES INTO THURSDAY. KEPT HIGHS IN THE 60S FOR
THURSDAY...AND WITH THE SFC HIGH NEARBY INTO THURSDAY NIGHT AND
DEW POINTS AROUND 40 F...LOWS THURSDAY NIGHT COULD BE QUITE COOL
IN THE LOW TO MID 40S.
LONG TERM (FRI-MON)...
MODELS IN GOOD AGREEMENT WITH 500MB NORTHWEST FLOW...A VERY TYPICAL
EARLY FALL REGIME IN THE EXTENDED PERIOD. THIS WILL BRING
QUIET...READ DRY...WEATHER WITH SEASONABLY COOL TEMPS TO THE
NORTHERN PLAINS FOR THE UPCOMING WEEKEND. THE 500MB RIDGING ACROSS
THE INTERMOUNTAIN WEST WILL SLOWLY BEGIN TO WORK ITS WAY
EAST...REALIZING A GRADUAL INCREASE OF TEMPS FROM FRIDAY TO
MONDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
GODON
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
354 AM CDT TUE AUG 14 2012
.SHORT TERM...
PRECIP CHANCE FOR TONIGHT AND TOMORROW AND TEMPERATURES THURSDAY
WILL BE THE PRIMARY FORECAST CHALLENGES FOR THE PERIOD.
WV LOOP AND UPPER AIR ANALYSIS SHOW NORTHWESTERLY FLOW ALOFT WITH
SIGNS OF AN EMBEDDED WEAK SHORTWAVE OVER THE NORTHERN PLAINS...BUT
THE MAIN UPPER SYSTEM IS STILL DIGGING INTO BRITISH COLUMBIA. THE
THE NAM AND RAP ALONG WITH THE HRRR HAVE SOME LIGHT PRECIP
ENTERING OUR CWA THIS MORNING AS THE WEAK SHORTWAVE MOVES
THROUGH...WHILE THE LARGER SCALE MODELS STAY DRY. THERE HAS BEEN
SOME RADAR RETURNS OVER BIS...BUT THEY HAVE PRODUCED ONLY A VERY
SMALL AMOUNT OF RAIN AND SEEM TO BE ON A DOWNWARD TREND. WILL
MONITOR THROUGH THE NEXT HOUR OR SO IN CASE SOME SPRINKLES NEED TO
BE ADDED TO THE SOUTHWESTERN CWA THIS MORNING...BUT DO NOT THINK
WE WILL SEE ANYTHING MEASURABLE.
HIGH PRESSURE WILL MOVE OFF TO THE EAST TODAY...WITH SOUTHERLY
WINDS STARTING TO PICK UP OVER THE WESTERN CWA AS THE SFC LOW
DEVELOPS OVER EASTERN MT. HIGHS SHOULD BE A BIT WARMER THAN
YESTERDAY. TONIGHT...THE UPPER TROUGH WILL BEGIN TO DIG INTO MT
FROM CANADA...WHICH SHOULD HELP PUSH THE SFC LOW OUT INTO THE
PLAINS. THERE ARE SOME VARIATIONS AS TO HOW MUCH PRECIP BREAKS OUT
TONIGHT IN THE WARM AIR ADVECTION ON THE FRONT SIDE OF THE SYSTEM.
NAM AND GFS ARE IN FAIRLY DECENT AGREEMENT ON SOME DEVELOPMENT
OVER THE SOUTHERN COUNTIES OVERNIGHT...SO CONCENTRATED THE HIGHEST
POPS IN THAT AREA THIS EVENING WITH HIGHS POPS AFTER MIDNIGHT AS
THE SYSTEM CONTINUES TO MOVE CLOSER.
THE UPPER TROUGH WILL DIG INTO THE DAKOTAS ON WEDNESDAY...AND MUCH
DEPENDS ON THE EXACT TIMING OF THE UPPER SYSTEM AND ASSOCIATED
COLD FRONT...AND THE MODELS CONTINUE TO STRUGGLE WITH THIS. THE
NAM IS NOW SLOWER THAN THE GFS...WITH THE FRONT THROUGH MOST OF
THE COUNTIES BY MID DAY BUT IT SHOULD REACH THE SOUTHEAST BY PEAK
HEATING AND THE NAM SHOWS SOME DECENT INSTABILITY. THE GFS IS
FASTER AND HAS THE FRONT THROUGH ALL BUT THE FAR EASTERN EDGE BY
00Z THURSDAY. MEANWHILE...THE ECMWF IS SLOWER WITH THE UPPER
SYSTEM AND CONTINUES TO SHOW LINGERING PRECIP OVER THE EASTERN
COUNTIES THROUGH EARLY THURSDAY MORNING. ECMWF SEEMS TO HAVE MORE
INTERNAL CONSISTENCY...WITH THE NAM AND GFS DOING A LOT OF FLIP
FLOPPING. STILL A LOT OF UNCERTAINTY AS TO THE TIMING. IN THE
INTERESTS OF INTERSITE CONSISTENCY...CONTINUED TO KEEP LIKELY POPS
IN THE EASTERN COUNTIES FOR WEDNESDAY AFTERNOON AND EVENING WITH
SOME EVEN LINGERING AFTER MIDNIGHT IN THE FAR EASTERN COUNTIES.
AFTER THE COLD FRONT MOVES THROUGH...850MB TEMPS WILL BE IN THE
SINGLE DIGITS C AND WITH THE COLD POOL ALOFT...THERE WILL BE A
FAIR AMOUNT OF CLOUDS LINGERING AND EVEN SOME SHOWERS IN THE
NORTHEASTERN COUNTIES INTO THURSDAY. KEPT HIGHS IN THE 60S FOR
THURSDAY...AND WITH THE SFC HIGH NEARBY INTO THURSDAY NIGHT AND
DEW POINTS AROUND 40 F...LOWS THURSDAY NIGHT COULD BE QUITE COOL
IN THE LOW TO MID 40S.
.LONG TERM (FRI-MON)...
MODELS IN GOOD AGREEMENT WITH 500MB NORTHWEST FLOW...A VERY TYPICAL
EARLY FALL REGIME IN THE EXTENDED PERIOD. THIS WILL BRING
QUIET...READ DRY...WEATHER WITH SEASONABLY COOL TEMPS TO THE
NORTHERN PLAINS FOR THE UPCOMING WEEKEND. THE 500MB RIDGING ACROSS
THE INTERMOUNTAIN WEST WILL SLOWLY BEGIN TO WORK ITS WAY
EAST...REALIZING A GRADUAL INCREASE OF TEMPS FROM FRIDAY TO
MONDAY.
&&
.AVIATION...
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AS MID AND UPPER
LEVEL CLOUDS INCREASE. LIGHT WINDS WILL INCREASE OUT OF THE
SOUTHEAST AFTER 18Z AS LOW PRESSURE DEVELOPS TO THE WEST.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
JR/JK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
120 AM CDT TUE AUG 14 2012
.DISCUSSION...
EMBEDDED S/WV IMPULSE CONTINUES TO SLIDE EAST-SOUTHEAST ACROSS
WESTERN SOUTH DAKOTA. ASSOCIATED PRECIPITATION WITH THIS FEATURE
MAINLY TO OUR SOUTH. AREA OF LINGERING LIGHT SHOWERS OVER SOUTH
CENTRAL NORTH DAKOTA EXPECTED TO DIMINISH NOW THROUGH 9-10Z AS
FORCING DECREASES WITH THE DEPARTURE OF THE WAVE. WILL MAINTAIN
SLIGHT CHANCES FOR SHOWERS AND ISOLATED THUNDERSTORMS WEST AND
CENTRAL THROUGH 12Z WITH MODELS DEPICTING SEVERAL WEAK WAVES IN
NORTHWEST FLOW ALOFT TRACKING ACROSS THE REGION. ALSO...SOUTHERLY
LLJ DEVELOPING OVER MY WEST WILL MIGRATE EAST INTO CENTRAL ND NOW
THROUGH 18Z. 00Z GFS/NAM ALONG WITH THE HRRR AND 4KM WRF ALL
GENERATE SHOWERS/POSSIBLE THUNDER WEST INTO CENTRAL THROUGH
12Z...WITH MODELS FOCUSING ON MY NORTHWEST AND NORTH CENTRAL WHERE
THE NOSE OF LLJ IS DEPICTED.
LINGERING PRECIPITATION LOOKS POSSIBLE 12-18Z TUESDAY MORNING OVER
MY CENTRAL AND EASTERN COUNTIES UNTIL THE LLJ WANES MID TO LATE
MORNING. DRY CONDITIONS FORECAST WEST. MODIFIED THE GRIDDED
FORECAST TO REFLECT THE ABOVE SCENARIO.
&&
.AVIATION...AT 11 PM CDT...A WARM FRONT EXTENDED ACROSS EASTERN
MONTANA INTO SOUTHWEST SOUTH DAKOTA. THE FRONT IS FORECAST TO MOVE
EAST INTO WESTERN NORTH DAKOTA TUESDAY AFTERNOON. AN AREA OF SHOWERS
IS DIMINISHING ACROSS SOUTHWEST NORTH DAKOTA. WITH RECENT RAINS
ADDED A MENTION OF 3 MILES IN LIGHT FOG/MIST ACROSS KDIK BETWEEN 09
AND 12Z. THERE IS SOME UNCERTAINTY IN WHETHER THIS WILL
HAPPEN...SO USED A TEMPO...AND KEPT IT LOW VFR. ELSEWHERE ALL TAF
SITES WILL BE VFR THROUGH THE 06Z TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
541 PM EDT TUE AUG 14 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION OVERNIGHT REACHING THE COAST BY
THURSDAY. HIGH PRESSURE WILL LINGER OVER OUR REGION WEDNESDAY AND
THURSDAY BEFORE THE NEXT COLD FRONT REACHES OUR AREA FROM THE
NORTHWEST LATE FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 530 PM...RECENT RADAR IMAGES INDICATE THAT COVERAGE OF TSRA
HAS BEEN INCREASING ACROSS THE FOOTHILLS OF THE CAROLINAS AND
NORTHEAST GA. LATEST CAPE ANALYSIS INDICATES THAT VALUES RANGE FROM
1500 TO 2000 J/KG ACROSS THE FOOTHILLS AND PIEDMONT...WITH DCAPE
VALUES RANGING FROM 1000 TO 1300 J/KG EAST OF THE MTNS. IN
ADDITION...EFFECTIVE SHEAR RANGES FROM 20 TO 30 KTS. GIVEN THE
ENVIRONMENT...FOOTHILL STORMS SHOULD ORGANIZE IN CLUSTERS...FORM
COLD POOLS...AND TRACK EAST. THE PRIMARY THREAT WILL REMAIN DAMAGING
WINDS...A FEW STRONGER STORMS MAY PRODUCE LARGE HAIL. I WILL UPDATE
THE FORECAST FOR POP PLACEMENT AND TIMING.
AS OF 145 PM...POPS HAD TO BE ADJUSTED AGAIN TO CHASE TRENDS. A
HEALTHY CU FIELD CAN BE SEEN ON VISIBLE...BUT JUST DOESN/T SEEM TO
BE ABLE TO BREAK THRU. THE 13Z HRRR IS THE CLOSEST TO REALITY...AND
IT REALLY ONLY HAS A FEW CELLS DEVELOPING ACRS THE NC MTNS THRU THE
AFTN HOURS. SO POPS WERE PUSHED BACK TO LATE AFTN/EVE...WHICH ARE
PROBABLY STILL OVERDONE. TEMPS ARE STILL LAGGING. ONE THING TO NOTE
IS THAT THE MODIFIED FFC SOUNDING THIS MORNING SHOWED THAT A FCST
MAX TEMP OF 87-89 STILL RESULTED IN SOME CIN. STILL EXPECT A VORT
MAX TO ENTER THE AREA LATER THIS AFTN...AND THAT MAY BE ENUF TO
BREAK THE CAP. WE/LL SEE.
LATER TONIGHT...AS WITH THE CONVECTION...FCST SNDGS AND MOISTURE
PROGS ON THE NAM AND GFS ARE VAGUE ON HOW MUCH CLOUD COVER WILL
LINGER OVERNIGHT. ANOTHER (STRONGER) VORT MAX...CURRENTLY OVER
MO...WILL PROVIDE DECENT QG FORCING LATE TNGT INTO WED MORNING. THIS
FEATURE WILL LIKELY KEEP SOME MID-HIGH CLOUDS AROUND. MEANWHILE...A
COLD FRONT WILL PUSH INTO THE AREA TOWARD DAYBREAK...HELPING KEEP
THINGS MIXED. SO TEMPS WILL BE NEAR NORMAL WITH PROBABLY NOT MUCH IN
THE WAY OF FOG. I ALSO KEEP A LINGERING SLGT CHC TO LOW-END CHC POP
DUE TO THE PASSAGE OF THE VORT MAX.
WEDNESDAY...THE COLD FRONT SHUD BE ABLE TO PUSH THRU THE REST OF THE
CWFA DURING THE DAY. GUIDANCE DOES TRY TO DEVELOP A LITTLE
CONVECTION ACRS MAINLY THE SE ZONES WITH DAYTIME HEATING NEAR THE
FRONT. OTHERWISE...SHUD BE A RELATIVELY DRY DAY WITH DECREASING
CLOUDS AND HIGHS NEAR NORMAL.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 245 PM TUESDAY...ZONAL FLOW DEVELOPS FOR THU AS SHORT WAVE
MOVES EAST OF THE AREA. SFC HIGH PRESSURE BUILDS IN AS WELL. EXPECT
DRYING LOW LEVELS AND WARMING MID LEVELS THU HELPING TO CAP THE
ATMOS. SHUD BE A DRY FCST WITH LOWS A LITTLE BELOW NORMAL AND HIGHS
NEAR NORMAL. HEIGHTS FALL FRI AS SHORT WAVES DIVE TOWARD THE AREA.
THIS HELPS PUSH A COLD FRONT FROM THE OH VALLEY TO JUST WEST OF THE
CWFA. LEE TROF DEVELOPS TO HELP PRODUCE LOW LEVEL CONVERGENCE. UPPER
DIVERGENCE BEGINS TO INCREASE AS UPPER JET MOVES TOWARD THE AREA AS
WELL. EXPECT INSTABILITY TO RETURN WITH MOISTENING LOW LEVELS AND
COOLING MID LEVELS. BEST CHC FOR PRECIP WILL BE OVER THE MTNS WHERE
MOISTURE AND FORCING ARE HIGHER...BUT SCT CONVECTION SHUD DEVELOP
ALL AREAS BY LATE AFTERNOON. LOWS THU NITE RISE TO AROUND NORMAL
WITH HIGHS FRIDAY NEAR TO SLIGHTLY ABOVE NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM TUESDAY...MUCH BETTER AGREEMENT BETWEEN THE 12Z GFS AND
THE 00Z ECMWF REGARDING THE DEVELOPING LONG WAVE TROF OVER THE ERN
CONUS THAN BETWEEN THE 06Z GFS AND 00Z ECMWF. AS MENTIONED ABOVE...
LONG WAVE TROF DEVELOPS OVER THE ERN CONUS AND REMAINS IN PLACE THRU
THE PERIOD. A SERIES OF WEAK SHORT WAVES MOVE THRU THE FLOW WITH THE
STRONGEST ON MONDAY. THE GFS THEN SHIFTS THE AXIS OF THE LONG WAVE
EAST ON TUE WHILE THE ECMWF HOLDS IN IN PLACE. AT THE SFC..A COLD
FRONT MOVES ACROSS THE AREA SAT...THEN STALLS TO OUR EAST AND SOUTH
THRU THE PERIOD. THE WAVE ON MONDAY MAY HELP DRAG THE FRONT BACK
TOWARD THE AREA BEFORE IT PUSHES SOUTH AND EAST OF US AGAIN FOR TUE.
GOOD AGREEMENT ON AT LEAST SCT POP SAT WITH THE FRONT...THEN
GUIDANCE DIFFERS FROM DAY TO DAY WITH PRECIP POTENTIAL DEPENDING ON
WHERE ANY WAVES MOVE ALONG THE FRONT AND IF THEY CAN PULL MOISTURE
BACK NORTH INTO THE CWFA. HAVE GONE WITH SCT POP SAT...SLIGHT CHC
SUN/MON THEN DRY TUE. TEMPS REMAIN NEARLY STEADY NEAR TO SLIGHTLY
BELOW NORMAL SAT THRU MON...THEN RISE BACK TO NEAR NORMAL FOR TUE.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
AT KCLT...A LOW CONFIDENCE FCST NEXT 24 HOURS...AS MODELS HAVING
TOUGH TIME WITH CONVECTION AND CLOUD COVER OVERALL. BASED ON THE
LATEST TRENDS...THINK CONVECTION WILL GET A LATE START IN THE NC
MTNS...WITH ACTIVITY NOT REACHING THE VICINITY UNTIL CLOSER TO 00Z.
SO I PUSHED THE TEMPO BACK TO 00Z. THEN AFTER 03Z...STILL A PROB30
FOR A COUPLE MORE HOURS. MEANWHILE...SW WINDS WILL BE AROUND 10
KNOTS OR SO WITH POSSIBLY A FEW GUSTS IN THE 15-18 KT RANGE. WIND
DECREASE TO UNDER 5 KNOTS AFTER SUNSET. GUIDANCE A BIT VAGUE ON HOW
MUCH MID AND HIGH CLOUDS LINGER OVERNIGHT. STILL EXPECT A FAIR
AMT...SO BETWEEN WINDS AND CLOUD COVER...NO FOG IS EXPECTED EARLY
WEDNESDAY. A WIND SHIFT TO NW WITH THE ARRIVAL OF A COLD FRONT IS
EXPECTED AFTER DAYBREAK WEDNESDAY...BUT WINDS SHUD STAY FAIRLY LIGHT.
ELSEWHERE...CONVECTION SLOW TO GET GOING...SO TEMPO GROUPS AND VCTS
MENTIONS HAVE BEEN PUSHED BACK AT ALL SITES. CONFIDENCE ON TIMING
AND COVERAGE IS STILL LOW. AS A COLD FRONT MOVES THROUGH EARLY
WEDNESDAY MORNING...THE MODELS SHOW BREAKS IN LOW VFR CLOUD COVER.
SW WINDS AROUND 10 KNOTS WITH OCCASIONAL LOW-END GUSTS TODAY (EXCEPT
AT KAVL)...DECREASING TO 5 KNOTS TONIGHT. BETWEEN WINDS AND CLOUD
COVER...FOG IS NOT EXPECTED EARLY WEDNESDAY...EVEN THO GUIDANCE DOES
HAVE FOG IN THE MTN VALLEYS. A FRONTAL PASSAGE AND A WIND SHIFT ARE
EXPECTED AFTER DAYBREAK WEDNESDAY...BUT WINDS SHUD REMAIN LIGHT.
OUTLOOK...THE CENTER OF SURFACE HIGH PRESSURE WILL SETTLE OVER THE
REGION ON WEDNESDAY AND REMAIN THROUGH THE WORK WEEK. A COLD FRONT
WILL BRING SOME MOISTURE TO THE AREA LATE FRIDAY INTO SATURDAY.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...NED
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...ARK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
251 PM EDT TUE AUG 14 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION OVERNIGHT REACHING THE COAST BY
THURSDAY. HIGH PRESSURE WILL LINGER BRIEFLY BEFORE THE NEXT COLD
FRONT MOVES TOWARD THE CAROLINAS LATE FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 145 PM...POPS HAD TO BE ADJUSTED AGAIN TO CHASE TRENDS. A
HEALTHY CU FIELD CAN BE SEEN ON VISIBLE...BUT JUST DOESN/T SEEM TO
BE ABLE TO BREAK THRU. THE 13Z HRRR IS THE CLOSEST TO REALITY...AND
IT REALLY ONLY HAS A FEW CELLS DEVELOPING ACRS THE NC MTNS THRU THE
AFTN HOURS. SO POPS WERE PUSHED BACK TO LATE AFTN/EVE...WHICH ARE
PROBABLY STILL OVERDONE. TEMPS ARE STILL LAGGING. ONE THING TO NOTE
IS THAT THE MODIFIED FFC SOUNDING THIS MORNING SHOWED THAT A FCST
MAX TEMP OF 87-89 STILL RESULTED IN SOME CIN. STILL EXPECT A VORT
MAX TO ENTER THE AREA LATER THIS AFTN...AND THAT MAY BE ENUF TO
BREAK THE CAP. WE/LL SEE.
LATER TONIGHT...AS WITH THE CONVECTION...FCST SNDGS AND MOISTURE
PROGS ON THE NAM AND GFS ARE VAGUE ON HOW MUCH CLOUD COVER WILL
LINGER OVERNIGHT. ANOTHER (STRONGER) VORT MAX...CURRENTLY OVER
MO...WILL PROVIDE DECENT QG FORCING LATE TNGT INTO WED MORNING. THIS
FEATURE WILL LIKELY KEEP SOME MID-HIGH CLOUDS AROUND. MEANWHILE...A
COLD FRONT WILL PUSH INTO THE AREA TOWARD DAYBREAK...HELPING KEEP
THINGS MIXED. SO TEMPS WILL BE NEAR NORMAL WITH PROBABLY NOT MUCH IN
THE WAY OF FOG. I ALSO KEEP A LINGERING SLGT CHC TO LOW-END CHC POP
DUE TO THE PASSAGE OF THE VORT MAX.
WEDNESDAY...THE COLD FRONT SHUD BE ABLE TO PUSH THRU THE REST OF THE
CWFA DURING THE DAY. GUIDANCE DOES TRY TO DEVELOP A LITTLE
CONVECTION ACRS MAINLY THE SE ZONES WITH DAYTIME HEATING NEAR THE
FRONT. OTHERWISE...SHUD BE A RELATIVELY DRY DAY WITH DECREASING
CLOUDS AND HIGHS NEAR NORMAL.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 245 PM TUESDAY...ZONAL FLOW DEVELOPS FOR THU AS SHORT WAVE
MOVES EAST OF THE AREA. SFC HIGH PRESSURE BUILDS IN AS WELL. EXPECT
DRYING LOW LEVELS AND WARMING MID LEVELS THU HELPING TO CAP THE
ATMOS. SHUD BE A DRY FCST WITH LOWS A LITTLE BELOW NORMAL AND HIGHS
NEAR NORMAL. HEIGHTS FALL FRI AS SHORT WAVES DIVE TOWARD THE AREA.
THIS HELPS PUSH A COLD FRONT FROM THE OH VALLEY TO JUST WEST OF THE
CWFA. LEE TROF DEVELOPS TO HELP PRODUCE LOW LEVEL CONVERGENCE. UPPER
DIVERGENCE BEGINS TO INCREASE AS UPPER JET MOVES TOWARD THE AREA AS
WELL. EXPECT INSTABILITY TO RETURN WITH MOISTENING LOW LEVELS AND
COOLING MID LEVELS. BEST CHC FOR PRECIP WILL BE OVER THE MTNS WHERE
MOISTURE AND FORCING ARE HIGHER...BUT SCT CONVECTION SHUD DEVELOP
ALL AREAS BY LATE AFTERNOON. LOWS THU NITE RISE TO AROUND NORMAL
WITH HIGHS FRIDAY NEAR TO SLIGHTLY ABOVE NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM TUESDAY...MUCH BETTER AGREEMENT BETWEEN THE 12Z GFS AND
THE 00Z ECMWF REGARDING THE DEVELOPING LONG WAVE TROF OVER THE ERN
CONUS THAN BETWEEN THE 06Z GFS AND 00Z ECMWF. AS MENTIONED ABOVE...
LONG WAVE TROF DEVELOPS OVER THE ERN CONUS AND REMAINS IN PLACE THRU
THE PERIOD. A SERIES OF WEAK SHORT WAVES MOVE THRU THE FLOW WITH THE
STRONGEST ON MONDAY. THE GFS THEN SHIFTS THE AXIS OF THE LONG WAVE
EAST ON TUE WHILE THE ECMWF HOLDS IN IN PLACE. AT THE SFC..A COLD
FRONT MOVES ACROSS THE AREA SAT...THEN STALLS TO OUR EAST AND SOUTH
THRU THE PERIOD. THE WAVE ON MONDAY MAY HELP DRAG THE FRONT BACK
TOWARD THE AREA BEFORE IT PUSHES SOUTH AND EAST OF US AGAIN FOR TUE.
GOOD AGREEMENT ON AT LEAST SCT POP SAT WITH THE FRONT...THEN
GUIDANCE DIFFERS FROM DAY TO DAY WITH PRECIP POTENTIAL DEPENDING ON
WHERE ANY WAVES MOVE ALONG THE FRONT AND IF THEY CAN PULL MOISTURE
BACK NORTH INTO THE CWFA. HAVE GONE WITH SCT POP SAT...SLIGHT CHC
SUN/MON THEN DRY TUE. TEMPS REMAIN NEARLY STEADY NEAR TO SLIGHTLY
BELOW NORMAL SAT THRU MON...THEN RISE BACK TO NEAR NORMAL FOR TUE.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
AT KCLT...A LOW CONFIDENCE FCST NEXT 24 HOURS...AS MODELS HAVING
TOUGH TIME WITH CONVECTION AND CLOUD COVER OVERALL. BASED ON THE
LATEST TRENDS...THINK CONVECTION WILL GET A LATE START IN THE NC
MTNS...WITH ACTIVITY NOT REACHING THE VICINITY UNTIL CLOSER TO 00Z.
SO I PUSHED THE TEMPO BACK TO 00Z. THEN AFTER 03Z...STILL A PROB30
FOR A COUPLE MORE HOURS. MEANWHILE...SW WINDS WILL BE AROUND 10
KNOTS OR SO WITH POSSIBLY A FEW GUSTS IN THE 15-18 KT RANGE. WIND
DECREASE TO UNDER 5 KNOTS AFTER SUNSET. GUIDANCE A BIT VAGUE ON HOW
MUCH MID AND HIGH CLOUDS LINGER OVERNIGHT. STILL EXPECT A FAIR
AMT...SO BETWEEN WINDS AND CLOUD COVER...NO FOG IS EXPECTED EARLY
WEDNESDAY. A WIND SHIFT TO NW WITH THE ARRIVAL OF A COLD FRONT IS
EXPECTED AFTER DAYBREAK WEDNESDAY...BUT WINDS SHUD STAY FAIRLY LIGHT.
ELSEWHERE...CONVECTION SLOW TO GET GOING...SO TEMPO GROUPS AND VCTS
MENTIONS HAVE BEEN PUSHED BACK AT ALL SITES. CONFIDENCE ON TIMING
AND COVERAGE IS STILL LOW. AS A COLD FRONT MOVES THROUGH EARLY
WEDNESDAY MORNING...THE MODELS SHOW BREAKS IN LOW VFR CLOUD COVER.
SW WINDS AROUND 10 KNOTS WITH OCCASIONAL LOW-END GUSTS TODAY (EXCEPT
AT KAVL)...DECREASING TO 5 KNOTS TONIGHT. BETWEEN WINDS AND CLOUD
COVER...FOG IS NOT EXPECTED EARLY WEDNESDAY...EVEN THO GUIDANCE DOES
HAVE FOG IN THE MTN VALLEYS. A FRONTAL PASSAGE AND A WIND SHIFT ARE
EXPECTED AFTER DAYBREAK WEDNESDAY...BUT WINDS SHUD REMAIN LIGHT.
OUTLOOK...THE CENTER OF SURFACE HIGH PRESSURE WILL SETTLE OVER THE
REGION ON WEDNESDAY AND REMAIN THROUGH THE WORK WEEK. A COLD FRONT
WILL BRING SOME MOISTURE TO THE AREA LATE FRIDAY INTO SATURDAY.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...ARK
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...ARK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
200 PM EDT TUE AUG 14 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION OVERNIGHT REACHING THE COAST BY
THURSDAY. HIGH PRESSURE WILL LINGER BRIEFLY BEFORE THE NEXT COLD
FRONT MOVES ACROSS THE CAROLINAS LATE FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 145 PM...POPS HAD TO BE ADJUSTED AGAIN TO CHASE TRENDS. A
HEALTHY CU FIELD CAN BE SEEN ON VISIBLE...BUT JUST DOESN/T SEEM TO
BE ABLE TO BREAK THRU. THE 13Z HRRR IS THE CLOSEST TO REALITY...AND
IT REALLY ONLY HAS A FEW CELLS DEVELOPING ACRS THE NC MTNS THRU THE
AFTN HOURS. SO POPS WERE PUSHED BACK TO LATE AFTN/EVE...WHICH ARE
PROBABLY STILL OVERDONE. TEMPS ARE STILL LAGGING. ONE THING TO NOTE
IS THAT THE MODIFIED FFC SOUNDING THIS MORNING SHOWED THAT A FCST
MAX TEMP OF 87-89 STILL RESULTED IN SOME CIN. STILL EXPECT A VORT
MAX TO ENTER THE AREA LATER THIS AFTN...AND THAT MAY BE ENUF TO
BREAK THE CAP. WE/LL SEE.
LATER TONIGHT...AS WITH THE CONVECTION...FCST SNDGS AND MOISTURE
PROGS ON THE NAM AND GFS ARE VAGUE ON HOW MUCH CLOUD COVER WILL
LINGER OVERNIGHT. ANOTHER (STRONGER) VORT MAX...CURRENTLY OVER
MO...WILL PROVIDE DECENT QG FORCING LATE TNGT INTO WED MORNING. THIS
FEATURE WILL LIKELY KEEP SOME MID-HIGH CLOUDS AROUND. MEANWHILE...A
COLD FRONT WILL PUSH INTO THE AREA TOWARD DAYBREAK...HELPING KEEP
THINGS MIXED. SO TEMPS WILL BE NEAR NORMAL WITH PROBABLY NOT MUCH IN
THE WAY OF FOG. I ALSO KEEP A LINGERING SLGT CHC TO LOW-END CHC POP
DUE TO THE PASSAGE OF THE VORT MAX.
WEDNESDAY...THE COLD FRONT SHUD BE ABLE TO PUSH THRU THE REST OF THE
CWFA DURING THE DAY. GUIDANCE DOES TRY TO DEVELOP A LITTLE
CONVECTION ACRS MAINLY THE SE ZONES WITH DAYTIME HEATING NEAR THE
FRONT. OTHERWISE...SHUD BE A RELATIVELY DRY DAY WITH DECREASING
CLOUDS AND HIGHS NEAR NORMAL.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 205 AM TUESDAY...UPPER HEIGHTS BEGIN TO RISE EARLY WED AND
FLAT RIDGING WILL PREVAIL THROUGH MOST OF THE SHORT TERM. SOME
LINGERING SHOWERS FROM TUE/S FRONTAL SYSTEM COULD AFFECT THE ERN
ZONES AND MORESO THE NC MTNS EARLY WED...BUT THE MODELS HAVE
DIFFERING IDEAS ON THIS SO LITTLE CHANGE WAS MADE TO THE GOING SLT
CHANCES. EXPECT GOOD INSOLATION WED/THU TO ALLOW MAX TEMPS TO REACH
A CAT OR SO ABOVE NORMAL. THE GOOD NEWS IS THE LLVL FLOW WILL REMAIN
W/LY AND AFTERNOON TD/S WILL MIX OUT TO AROUND 60 F...MAKING FOR
WARM BUT RATHER PLEASANTLY DRY CONDITIONS EACH DAY. ISOL TO SCT
SHOWERY ACTIVITY SHOULD DEVELOP ACROSS THE WRN ZONES THU NIGHT AS A
PREFRONTAL TROF BEGINS TO DEEPEN AND MOVES TOWARD THE AREA.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 130 AM EDT TUESDAY...GOOD AGREEMENT IS HAD BTW THE LATEST MID
RANGE MODELS WRT THE LARGE UPPER LOW AND THE EVOLUTION OF THE SFC
FRONT APPROACHING THE NC MTNS BY SAT. BEFORE THAT...A SMALL SCALE
UPPER RIDGE BREAKS DOWN OVER THE FCST AREA AND LLVL WINDS RESPOND
OUT OF THE SW ALLOWING A MOISTENING OF THE LLVLS AND AN INCREASE IN
MECHANICAL LIFT ACROSS THE HIGHER TERRAIN. DEWPOINTS WILL RETURN TO
THE MID TO UPPER 60S AND SCT AFTERNOON CONVECTION IS LIKELY ACROSS
THE MAJORITY OF THE AREA INTO THE EVENING. THE PREFRONTAL TROF WILL
PUSH INTO THE AREA EARLY SAT AND -SHRA WILL BE EXPECTED EARLY ON
ACROSS THE NC MTNS...THEN SPREADING EAST AS THE DAY PROGRESSES.
MODEL SOUNDINGS STILL INDICATE LOWER END SBCAPE AND MUCAPE...ESP
ACROSS THE NON/MTNS...WHILE DEEP LAYERED SHEAR REACHES A RESPECTABLE
30 KTS OR SO. THUS...STRONG STORMS ARE PROBABLE WITH A FEW POSSIBLY
REACHING SEVERE CRITERIA SAT AFTERNOON/EVENING. HIGH PRESSURE BUILDS
IN EARLY SUN AND REMAINS THROUGH MON WHICH WILL MAKE FOR A COUPLE
DRY DAYS. MAX TEMPS WILL BE RIGHT AROUND NORMAL FRI AND A FEW
DEGREES COOL SAT WITH ALL THE CLOUD COVER. SUN AND MON WILL
EXPERIENCE AN AIRMASS MIX...SO MAXES SHOULD BE HELD A COUPLE CATS
BELOW NORMAL EACH OF THOSE DAYS.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AT KCLT...A LOW CONFIDENCE FCST NEXT 24 HOURS...AS MODELS HAVING
TOUGH TIME WITH CONVECTION AND CLOUD COVER OVERALL. BASED ON THE
LATEST TRENDS...THINK CONVECTION WILL GET A LATE START IN THE NC
MTNS...WITH ACTIVITY NOT REACHING THE VICINITY UNTIL CLOSER TO 00Z.
SO I PUSHED THE TEMPO BACK TO 00Z. THEN AFTER 03Z...STILL A PROB30
FOR A COUPLE MORE HOURS. MEANWHILE...SW WINDS WILL BE AROUND 10
KNOTS OR SO WITH POSSIBLY A FEW GUSTS IN THE 15-18 KT RANGE. WIND
DECREASE TO UNDER 5 KNOTS AFTER SUNSET. GUIDANCE A BIT VAGUE ON HOW
MUCH MID AND HIGH CLOUDS LINGER OVERNIGHT. STILL EXPECT A FAIR
AMT...SO BETWEEN WINDS AND CLOUD COVER...NO FOG IS EXPECTED EARLY
WEDNESDAY. A WIND SHIFT TO NW WITH THE ARRIVAL OF A COLD FRONT IS
EXPECTED AFTER DAYBREAK WEDNESDAY...BUT WINDS SHUD STAY FAIRLY LIGHT.
ELSEWHERE...CONVECTION SLOW TO GET GOING...SO TEMPO GROUPS AND VCTS
MENTIONS HAVE BEEN PUSHED BACK AT ALL SITES. CONFIDENCE ON TIMING
AND COVERAGE IS STILL LOW. AS A COLD FRONT MOVES THROUGH EARLY
WEDNESDAY MORNING...THE MODELS SHOW BREAKS IN LOW VFR CLOUD COVER.
SW WINDS AROUND 10 KNOTS WITH OCCASIONAL LOW-END GUSTS TODAY (EXCEPT
AT KAVL)...DECREASING TO 5 KNOTS TONIGHT. BETWEEN WINDS AND CLOUD
COVER...FOG IS NOT EXPECTED EARLY WEDNESDAY...EVEN THO GUIDANCE DOES
HAVE FOG IN THE MTN VALLEYS. A FRONTAL PASSAGE AND A WIND SHIFT ARE
EXPECTED AFTER DAYBREAK WEDNESDAY...BUT WINDS SHUD REMAIN LIGHT.
OUTLOOK...THE CENTER OF SURFACE HIGH PRESSURE WILL SETTLE OVER THE
REGION ON WEDNESDAY AND REMAIN THROUGH THE WORK WEEK. A COLD FRONT
WILL BRING SOME MOISTURE TO THE AREA LATE FRIDAY INTO SATURDAY.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...ARK
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...ARK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1037 AM EDT TUE AUG 14 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION OVERNIGHT REACHING THE COAST BY
THURSDAY. HIGH PRESSURE WILL LINGER BRIEFLY BEFORE THE NEXT COLD
FRONT MOVES ACROSS THE CAROLINAS LATE FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM...A BIT OF A COMPLICATED FCST FOR THIS MORNING UPDATE.
THE WATER VAPOR LOOP AND RAP SHOW A SERIES OF VORT MAXIMA ROUNDING
THE MEAN UPR TROF AXIS...WITH ONE OF THEM PROGGED TO CROSS THE CWFA
THIS AFTN/EVE. MEANWHILE...AS WEAK SFC LOW WAS ANALYZED INVOF OH
WITH A COLD FRONT EXTENDING SOUTH ACRS THE TN VLY TO THE SRN PLAINS.
VISIBLE SAT IMAGERY SHOWS COPIOUS CLOUD COVER FROM LAST NIGHT/S
CONVECTION...WITH A REMNANT COLD POOL ACRS ERN TN/N GA AND WRN HALF
OF THE CWFA.
SO THE MAIN CHALLENGE TODAY IS TIMING AND COVERAGE OF CONVECTION AND
WHAT SEVERE THREAT WE MAY HAVE. SPC HAS EXPANDED THE NEW DAY1
CONVECTIVE OUTLOOK TO INCLUDE THE ENTIRE CWFA. THE THINKING IS THAT
WITH 25-30 KTS OF 0-6 KM BULK SHEAR AND DPVA FROM AFOREMENTIONED S/W
ENERGY...ANY CLEARING OF CLOUDS WILL ALLOW ENUF DESTABILIZATION FOR
AT LEAST SCATTERED STORMS DEVELOPING WITHIN THE WARM SECTOR ALONG
AND AHEAD OF THE COLD FRONT AND BECOMING LOOSELY ORGANIZED INTO
MULTI-CELL CLUSTERS. SO WITH THIS UPDATE...I WILL PUSH BACK THE
HIGHER POPS UNTIL MID AFTN...AND WIL UPDATE THE HWO TO ADD MENTION
OF SEVERE THREAT. CONFIDENCE WILL INCREASE ONCE TRENDS ON THE CLOUD
COVER BECOME BETTER ESTABLISHED.
PREVIOUS DISCUSSION...
AT 300 AM EDT TUESDAY...AN UPPER TROUGH WIL PERSIST TODAY AND
TONIGHT FORM THE GREAT LAKES TO THE NORTHEAST GULF OF MEXICO. A
SHORTWAVE WILL EXIT THE CAROLINAS THIS MORNING. A SECOND SHORTWAVE
WILL CROSS THE MID MS RIVER VALLEY THIS EVENING...REACHING THE TN
VALLEY LATE TONIGHT. A WEAK SURFACE WAVE AND ASSOCIATED COLD FRONT
WILL CROSS THE GULF STATES TODAY...WHILE MOISTURE INCREASES AHEAD OF
IT. CAPE WILL APPROACH 1000 J/KG BY THIS AFTERNOON...AND SPEED AND
DIRECTIONAL SHEAR WILL EXIST. IF INSTABILITY WERE A BIT GREATER...
DAMAGING WIND GUSTS WOULD BE MORE OF A CONCERN...AS LOW LEVELS ARE
RELATIVELY DRY. CHANCE POPS WILL BE CARRIED TODAY...WITH NEAR LIKELY
POPS IN THE MOUNTAINS. MAXIMUM TEMPERATURES WILL BE SLIGHTLY BELOW
NORMAL.
THE COLD FRONT MOVES THROUGH OUR AREA TONIGHT. THE GFS IS A BIT
FASTER THAN THE NAM TO BRING THE FRONT...AND DRY AIR IN ITS WAKE...
EAST ACROSS OUR AREA. SMALL POPS WILL BE MAINTAINED THROUGH MOST OF
THE NIGHT...LINGERING LASTLY ALONG THE TN BORDER FOR UPSLOPE FLOW.
MINIMUM TEMPERATURES WILL BE AROUND NORMAL.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 205 AM TUESDAY...UPPER HEIGHTS BEGIN TO RISE EARLY WED AND
FLAT RIDGING WILL PREVAIL THROUGH MOST OF THE SHORT TERM. SOME
LINGERING SHOWERS FROM TUE/S FRONTAL SYSTEM COULD AFFECT THE ERN
ZONES AND MORESO THE NC MTNS EARLY WED...BUT THE MODELS HAVE
DIFFERING IDEAS ON THIS SO LITTLE CHANGE WAS MADE TO THE GOING SLT
CHANCES. EXPECT GOOD INSOLATION WED/THU TO ALLOW MAX TEMPS TO REACH
A CAT OR SO ABOVE NORMAL. THE GOOD NEWS IS THE LLVL FLOW WILL REMAIN
W/LY AND AFTERNOON TD/S WILL MIX OUT TO AROUND 60 F...MAKING FOR
WARM BUT RATHER PLEASANTLY DRY CONDITIONS EACH DAY. ISOL TO SCT
SHOWERY ACTIVITY SHOULD DEVELOP ACROSS THE WRN ZONES THU NIGHT AS A
PREFRONTAL TROF BEGINS TO DEEPEN AND MOVES TOWARD THE AREA.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 130 AM EDT TUESDAY...GOOD AGREEMENT IS HAD BTW THE LATEST MID
RANGE MODELS WRT THE LARGE UPPER LOW AND THE EVOLUTION OF THE SFC
FRONT APPROACHING THE NC MTNS BY SAT. BEFORE THAT...A SMALL SCALE
UPPER RIDGE BREAKS DOWN OVER THE FCST AREA AND LLVL WINDS RESPOND
OUT OF THE SW ALLOWING A MOISTENING OF THE LLVLS AND AN INCREASE IN
MECHANICAL LIFT ACROSS THE HIGHER TERRAIN. DEWPOINTS WILL RETURN TO
THE MID TO UPPER 60S AND SCT AFTERNOON CONVECTION IS LIKELY ACROSS
THE MAJORITY OF THE AREA INTO THE EVENING. THE PREFRONTAL TROF WILL
PUSH INTO THE AREA EARLY SAT AND -SHRA WILL BE EXPECTED EARLY ON
ACROSS THE NC MTNS...THEN SPREADING EAST AS THE DAY PROGRESSES.
MODEL SOUNDINGS STILL INDICATE LOWER END SBCAPE AND MUCAPE...ESP
ACROSS THE NON/MTNS...WHILE DEEP LAYERED SHEAR REACHES A RESPECTABLE
30 KTS OR SO. THUS...STRONG STORMS ARE PROBABLE WITH A FEW POSSIBLY
REACHING SEVERE CRITERIA SAT AFTERNOON/EVENING. HIGH PRESSURE BUILDS
IN EARLY SUN AND REMAINS THROUGH MON WHICH WILL MAKE FOR A COUPLE
DRY DAYS. MAX TEMPS WILL BE RIGHT AROUND NORMAL FRI AND A FEW
DEGREES COOL SAT WITH ALL THE CLOUD COVER. SUN AND MON WILL
EXPERIENCE AN AIRMASS MIX...SO MAXES SHOULD BE HELD A COUPLE CATS
BELOW NORMAL EACH OF THOSE DAYS.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
AT KCLT...THE DEW POINT DEPRESSION IS NOT SUPPORTIVE OF A FOG
RESTRICTION THIS MORNING. LOW LEVEL CLOUD COVER WILL SPREAD INTO THE
AREA FORM THE SE THIS MORNING AHEAD OF AN APPROACHING COLD FRONT.
LOW VFR CIGS ARE EXPECTED BY AFTERNOON...AND A TEMPO WILL BE CARRIED
FOR AFTERNOON CONVECTION. THE MODELS SUGGEST THAT BREAKS WILL APPEAR
AS THE FRONT MOVES THROUGH TONIGHT...BUT A LOW VFR CIG WILL WILL
GENERALLY PERSIST. SW WINDS WILL INCREASE TO AROUND 10 KNOTS
TODAY...DECREASING TO 5 KNOTS AFTER SUNSET. BETWEEN WINDS AND CLOUD
COVER...NO FOG IS EXPECTED EARLY WEDNESDAY. FRONTAL PASSAGE AND A
WIND SHIFT ARE NOT EXPECTED UNTIL AFTER DAYBREAK WEDNESDAY.
ELSEWHERE...FOG HAS FAILED TO FORM...EVEN WHERE DEW POINT
DEPRESSIONS ARE LOW...AND CONFIDENCE IS DECREASING ON ANY
RESTRICTIONS THIS MORNING. LOW CLOUDS WILL INCREASE FROM THE SW THIS
MORNING...AND SC SITES COULD SEE CONVECTION THIS MORNING BASED ON
RADAR TRENDS IN GA. CONVECTION IS EXPECTED TO PEAK THIS AFTERNOON
WITH BETTER INSTABILITY. AS A COLD FRONT MOVES THROUGH TONIGHT...THE
MODELS SHOW BREAKS IN LOW VFR CLOUD COVER. SW WINDS WILL APPROACH 10
KNOTS TODAY...DECREASING TO 5 KNOTS TONIGHT. BETWEEN WINDS AND CLOUD
COVER...FOG IS NOT EXPECTED EARLY WEDNESDAY. FRONTAL PASSAGE AND A
WIND SHIFT ARE EXPECTED AFTER DAYBREAK WEDNESDAY.
OUTLOOK...A SLOW MOVING COLD FRONT IS EXPECTED TO CROSS THE SOUTHERN
APPALACHIAN REGION TUESDAY NIGHT...BRINGING A CHC FOR SHRA/TSRA. THE
CENTER OF SURFACE HIGH PRESSURE WILL SETTLE OVER THE REGION ON
WEDNESDAY AND REMAIN THROUGH THE WORK WEEK.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...ARK/JAT
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...JAT
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
339 PM CDT TUE AUG 14 2012
.DISCUSSION.../ISSUED AT 339 PM CDT/
COMPLEX WEAK TROUGH WORKING ACROSS THE EASTERN DAKOTAS THIS
AFTERNOON. ONE CORE DIGGING SOUTHWARD THROUGH EASTERN
NEBRASKA...WITH COOL AIR POOL LEFTOVER AROUND THE KYKN AREA FROM
EARLIER SHOWERS/THUNDERSTORMS TO THE SOUTH. CAN SEE A SECONDARY
IMPULSE DROPPING SOUTHEAST FROM SOUTHERN NORTH DAKOTA TOWARD
SOUTHWEST MINNESOTA. SUBTLE BOUNDARY ON RADAR NORTH OF KFSD...AND
BEST LOWER TO MID LEVEL BOUNDARY WILL REMAIN JUST NORTH AND EAST OF
THE AREA THROUGH THE EVENING HOURS BEFORE STARTING TO NUDGE
NORTHEAST. ELEVATED THETA E ADVECTION FOCUSES THROUGH THE NORTHEAST
HALF OF THE AREA OVERNIGHT...AND CONCENTRATION TO POPS MADE THROUGH
THAT AREA... WINDING DOWN LATER IN THE NIGHT. HRRR HAS SOME SUPPORT
TO DEVELOPMENT DURING THE EVENING IN THIS AREA...KICKING UP AS THE
LOW LEVEL JET STARTS TO INCREASE AROUND SUNSET.
ON WEDNESDAY...MUCH OF THE DAY LOOKS TO BE INERT WEATHERWISE...
WITH VERY WARM 700 HPA TEMPERATURES AND SURFACE FRONT APPROACHING
FROM THE WEST. 3 HOUR PRESSURE RISES OF 5-6 HPA/3H WILL PRESS IN
BEHIND BOUNDARY...WITH MIXED LAYER WINDS TOPPING OUT 30-35 KNOTS.
HAVE ISSUED A WIND ADVISORY FOR THE FAR SOUTHWEST AREAS...WITH A
POTENTIAL THAT MAY NEED A SLIGHT EASTWARD EXPANSION TOWARD THE JAMES
VALLEY.
HARD TO PICTURE SURFACE BOUNDARY GOING CONVECTIVE WITH A MID
AFTERNOON INHIBITION OF 200-300 J/KG...SO MAY END UP GOING A BIT
BEHIND BOUNDARY INITIALLY...SO HEDGED POPS A BIT FURTHER BACK
WESTWARD FROM EXPECTED BOUNDARY LOCATION...WHICH SHOULD BE NEAR A
KOTG TO KLCG LINE BY 00Z. DEEP LAYER SHEAR AROUND 40 KNOTS WILL
SUGGEST A GOOD POTENTIAL FOR ORGANIZATION AND DISCRETE STRUCTURES
INITIALLY WITH CROSS BOUNDARY SHEAR. ONE PROBLEM WILL BE THE
AVAILABLE MOISTURE...AS DO EXPECT THAT PREFRONTAL AREAS WILL MIX
VERY WELL...WELL INTO THE 90S TEMPWISE...WITH DEWPOINTS PERHAPS INTO
THE LOWER 50S. CAPE WILL PROBABLY BE LIMITED TO 1000-1500 J/KG.
SHOULD BE ENOUGH FOR A HAIL/WIND THREAT FOR THE VERY LATE AFTERNOON.
/CHAPMAN
WEDNESDAY NIGHT WILL SEE THE CONVECTION ALONG THE FRONT RACE QUICKLY
EAST OUT OF THE CWA...WILL HAVE SOME LOWER POPS IN THE FAR EASTERN
PART OF THE CWA THROUGH ABOUT 9Z IN CASE BOUNDARY IS A LITTLE SLOWER
BUT OVERALL MOST ACTIVITY LIKELY TO BE FROM ABOUT 23Z THROUGH 4Z AND
MAINLY IN SOUTHWEST MINNESOTA AND NORTHWEST IOWA. WILL MAINTAIN A
THREAT FOR SEVERE WEATHER THROUGH THIS TIME AS THE DEEPER BULK SHEAR
VALUES INCREASE TO ABOUT 40 KNOTS WITH FAIRLY STRONG CAPE VALUES.
COOLER AND DRIER AIR WILL PUSH IN BEHIND THE FRONT WITH BREEZY
EVENING CONDITIONS LEADING INTO A BIT OF A BREEZY AND COOL THURSDAY.
LOWS IN THE MID 50S WITH 10 TO 15 MPH WIND WILL LEAD TOWARDS HIGHS
THURSDAY FROM THE UPPER 60S IN SOUTHWEST MINNESOTA TO THE MID 70S IN
SOUTH CENTRAL SOUTH DAKOTA. EXPECTING A BIT OF CLOUD COVER TO LINGER
OVER THE SOOTH AND EAST PARTS OF THE CWA AS THE WAVE ROTATES
EASTWARD WHICH WILL AID IN LIMITING THE HIGH TEMPERATURE POTENTIAL.
FRIDAY MORNING PUTS THE AREA IN THE HEART OF THE COOLER AIR AS HIGH
PRESSURE SHOULD BE NEAR THE BIG SIOUX RIVER VALLEY AROUND 12Z
FRIDAY. UTILITY OF THE LOCAL EXTREME CLIMATOLOGY FITS WELL FOR
RECORD TO NEAR RECORD MORNING LOWS SO WILL AIM A LITTLE BELOW THE
COLDEST GUIDANCE WITH MOST AREAS DROPPING DOWN INTO THE LOWER TO
MIDDLE 40S.
FRIDAY WILL BE A FAIRLY COOL BUT VERY PLEASANT DAY WITH DRY AIR IN
PLACE...HIGH PRESSURE ONLY GRADUALLY SHIFTING SOUTHEAST AND 925MB
TEMPERATURES IN THE MID TO UPPER TEENS. THIS SHOULD BRING A MOSTLY
SUNNY DAY WITH HIGHS FROM THE LOWER TO MIDDLE 70S.
IN THE LATTER PERIODS(SAT/TUE)...MODELS FAIRLY AGREEABLE UPON
DEVELOPING A LARGE SCALE HUDSON BAY LOW...WITH RIDGING OVER THE
WESTERN UNITED STATES. THIS SUGGESTS NORMAL TO BELOW NORMAL
CONDITIONS WITH ONLY SPOTTY CHANCES FOR RAIN AND THUNDERSTORMS. THE
GFS IS THE MOST AGGRESSIVE AT DEVELOPING THIS LOW WHILE THE ECMWF
AND CANADIAN SUGGEST THAT A SHORTWAVE WILL ROUND THE RIDGE IN THE
WEST LATE IN THE PERIOD AND HELP EJECT THE HUDSON BAY LOW EASTWARD.
NOT BUYING INTO THIS SCENARIO COMPLETELY AS THIS WAVE COULD JUST
ROUND THE WESTERN SIDE OF THE HUDSON BAY LOW...FURTHER DEEPENING IT.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. BETTER THREAT
FOR CONVECTION LOOKS TO OCCUR THIS EVENING NORTH AND EAST OF THE
AREA...WITH LESS FORCING/CONVERGENCE OF MID LEVEL WIND TO THE SOUTH
AND WEST. HOWEVER...POTENTIAL FOR CONVECTION AT TAF SITES DEEMED TOO
LOW TO MENTION IN THE ONGOING SET...BUT DID ADD IN A COUPLE HOURS OF
SHOWERS FOR KSUX DURING THE MID TO LATE AFTERNOON ON PERIPHERY OF
CORE OF WAVE DIGGING THROUGH EASTERN NEBRASKA. /CHAPMAN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...WIND ADVISORY 18Z WED THROUGH 00Z WED FOR SDZ050-057-063.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
115 PM CDT TUE AUG 14 2012
.DISCUSSION.../ISSUED AT 115 PM CDT/
WEAK WAVE PUSHING SOUTHEAST THROUGH SOUTHERN SOUTH DAKOTA...WITH A
LONG HISTORY OF PRECIPITATION WHILE DIGGING SOUTHEAST OUT OF MONTANA.
EXPECT A BULK OF ACTIVITY TO SHIFT SOUTHEAST INTO EASTERN
NEBRASKA...AND KEPT HIGHEST POPS GOING ALONG THE MISSOURI RIVER
CORRIDOR THROUGH THE MID AFTERNOON. HOWEVER...A FAIRLY DISTINCT BAND
OF MID LEVEL INSTABILITY IN PLACE...AND GIVEN THE CONTINUATION OF
850-700 HPA THETA E ADVECTION...WILL PROBABLY FIND A LEAST A MINIMAL
THREAT OF MID BASED SHOWERS/ISOLATED THUNDER PUSHING EASTWARD DURING
THE AFTERNOON. HRRR A LITTLE OVERZEALOUS WITH PRECIPITATION...AS
TYPICAL...BUT IDEA THAT SOME THREAT SHIFTS EAST TOWARD A KMML TO
KSUX AXIS LATER IN THE DAY SEEMS REASONABLE...AS DOES POTENTIAL FOR
SOME DEVELOPMENT ON BACK EDGE OF CLOUDS BY LATER THIS AFTERNOON. AS
A RESULT OF THE MUCH MORE EXTENSIVE CLOUDS...DID LOWER SOME TEMPS 3
TO 5 DEGREES IN HEART OF THE AREA...BUT THE FAR EAST WITH DELAY IN
CLOUD ONSET...AND THE FAR WEST WILL BREAK OUT ENOUGH TO REACH
EARLIER POTENTIAL. UPDATES OUT. /CHAPMAN
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. BETTER THREAT
FOR CONVECTION LOOKS TO OCCUR THIS EVENING NORTH AND EAST OF THE
AREA...WITH LESS FORCING/CONVERGENCE OF MID LEVEL WIND TO THE SOUTH
AND WEST. HOWEVER...POTENTIAL FOR CONVECTION AT TAF SITES DEEMED TOO
LOW TO MENTION IN THE ONGOING SET...BUT DID ADD IN A COUPLE HOURS OF
SHOWERS FOR KSUX DURING THE MID TO LATE AFTERNOON ON PERIPHERY OF
CORE OF WAVE DIGGING THROUGH EASTERN NEBRASKA. /CHAPMAN
&&
.PREV DISCUSSION.../ISSUED AT 348 AM CDT/
YET ANOTHER PLEASANT SUMMER DAY EXPECTED ACROSS THE REGION TODAY
WITH SURFACE HIGH PRESSURE SLIPPING SOUTHEASTWARD INTO THE MID
MISSISSIPPI VALLEY BY THIS AFTERNOON. RETURN FLOW BEHIND THE HIGH
WILL BRING INCREASED SOUTHERLY FLOW...WHICH WILL BE GREATEST ACROSS
OUR WESTERN HALF. WINDS SHOULD BECOME BREEZY INTO THE JAMES VALLEY
AND WESTWARD. HIGHS WILL BE WARMER TODAY THAN IN PREVIOUS DAYS WITH
HIGHS MAINLY IN THE 80S...TO AROUND 90 IN SOUTH CENTRAL SOUTH
DAKOTA.
LOW LEVEL JET IS EXPECTED TO START KICKING IN THIS EVENING AND
OVERNIGHT ACROSS CENTRAL AND EASTERN PORTIONS OF THE FORECAST AREA.
THIS WILL BE COUPLED WITH A WEAK MID LEVEL WAVE WHICH TRACKS EAST
SOUTHEAST THROUGH THE FORECAST AREA. THIS SHOULD BE ENOUGH TO SQUEAK
OUT SOME ISOLATED THUNDERSTORMS...ALTHOUGH THE MEAGER MOISTURE COULD
WILL KEEP PRECIPITATION AMOUNTS WELL IN CHECK.
A BROAD CANADIAN UPPER TROUGH DIGGING INTO THE NORTHERN PLAINS WILL
DROP A FAIRLY POTENT COLD FRONT ACROSS THE NORTHERN PLAINS ON
WEDNESDAY. MIXY SOUTH SOUTHWEST WINDS AHEAD OF THE FRONT WILL USHER
IN THE WARMEST DAY OF THE WEEK AHEAD OF THE FRONT...WITH HIGHS IN
THE UPPER 80S TO MID 90S. THE FRONT WILL TRACK THROUGH THE FORECAST
AREA WEDNESDAY AFTERNOON AND EVENING...ACCOMPANIED BY A STRONG MID
LEVEL WAVE A FRONTOGENESIS. CAPPING SHOULD HOLD OFF INITIAL
CONVECTION IN OUR FAR WESTERN COUNTIES EARLY IN THE DAY...HOWEVER
WILL LIKELY SEE SCATTERED STORMS START FIRING EAST OF A YANKTON TO
BROOKINGS LINE IN THE LATE AFTERNOON AND BECOME MORE LIKELY ACROSS
NORTHWEST IOWA AND SOUTHWEST MINNESOTA IN THE EVENING HOURS AS
DAYTIME HEATING PEAKS AND THE 850 MB WAVE/FRONT DIGS INTO THE AREA.
STEEP LAPSE RATES APPROACHING 10C/KM...1500+ J/KG CAPE AND 40 KT
BULK SHEAR PER NAM FORECAST SOUNDINGS SUGGEST THE POTENTIAL FOR SOME
SEVERE STORMS WITH HAIL AND WIND CONCERNS...ALTHOUGH LOWER LEVEL
MOISTURE DOES APPEAR SOMEWHAT LACKING. WILL CONTINUE WITH LIKELY TO
CATEGORICAL POPS WEDNESDAY EVENING ACROSS NORTHWEST IOWA AND
SOUTHWEST MINNESOTA.
DRY NORTHWEST FLOW SETTLES IN FOR THE LATER HALF OF THE WEEK.
TEMPERATURES WILL BE QUITE A BIT COOLER ON THURSDAY WITH BREEZY
NORTHERLY WINDS ADVECTING IN SOME BELOW NORMAL TEMPERATURES AND
CLOUDS DECREASING THROUGH THE MORNING. HIGHS WILL LIKELY ONLY BE IN
THE 70S ON THURSDAY AND FRIDAY...BUT WILL BE ON A GRADUAL WARMING
TREND THROUGH THE WEEKEND. OVERALL CONDITIONS LOOK PRETTY DRY WITH
ONLY SOME MINOR MOISTURE STARVED WAVES TRACKING THROUGH THE PLAINS
IN THE NORTHWEST FLOW. GFS PAINTS SOME LIGHT POPS ACROSS THE AREA
AROUND THE SATURDAY TIME FRAME...WHICH IS NOT WELL SUPPORTED IN THE
OTHER MODELS. WILL CONTINUE TO LEAVE OUT ANY MENTION OF POPS BEYOND
EARLY THURSDAY WITH LITTLE CONFIDENCE IN THE TIMING AND TRACK OF ANY
MID LEVEL WAVE THAT DOES MAKE AN APPEARANCE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1117 AM CDT TUE AUG 14 2012
.DISCUSSION.../ISSUED AT 1117 AM CDT/
WEAK WAVE PUSHING SOUTHEAST THROUGH SOUTHERN SOUTH DAKOTA...WITH A
LONG HISTORY OF PRECIPITATION WHILE DIGGING SOUTHEAST OUT OF MONTANA.
EXPECT A BULK OF ACTIVITY TO SHIFT SOUTHEAST INTO EASTERN
NEBRASKA...AND KEPT HIGHEST POPS GOING ALONG THE MISSOURI RIVER
CORRIDOR THROUGH THE MID AFTERNOON. HOWEVER...A FAIRLY DISTINCT BAND
OF MID LEVEL INSTABILITY IN PLACE...AND GIVEN THE CONTINUATION OF
850-700 HPA THETA E ADVECTION...WILL PROBABLY FIND A LEAST A MINIMAL
THREAT OF MID BASED SHRA/ISOLD TSRA PUSHING EASTWARD DURING THE
AFTERNOON. HRRR A LITTLE OVERZEALOUS WITH PRECIPTIATION...AS
TYPICAL...BUT IDEA THAT SOME THREAT SHIFTS EAST TOWARD A KMML TO
KSUX AXIS LATER IN THE DAY SEEMS REASONABLE...AS DOES POTENTIAL FOR
SOME DEVELOPMENT ON BACK EDGE OF CLOUDS BY LATER THIS AFTERNOON.
AS A RESULT OF THE MUCH MORE EXTENSIVE CLOUDS...DID LOWER SOME TEMPS
3 TO 5 DEGREES IN HEART OF THE AREA...BUT THE FAR EAST WITH DELAY IN
CLOUD ONSET...AND THE FAR WEST WILL BREAK OUT ENOUGH TO REACH
EARLIER POTENTIAL. UPDATES OUT.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. SOUTHERLY WINDS
WILL INCREASE THROUGHOUT THE DAY TODAY. LOW LEVEL JET WILL DEVELOP
TONIGHT...AND MAY CREATE ISOLATED THUNDERSTORMS ACROSS CENTRAL SOUTH
DAKOTA. HAVE A TEMPO IN KHON TAF FOR THIS. THERE IS A CHANCE FOR
THUNDERSTORMS IN KFSD TAF...BUT CONFIDENCE IS LOWER SO LEFT MENTION
OUT FOR NOW.
&&
.PREV DISCUSSION.../ISSUED AT 348 AM CDT/
YET ANOTHER PLEASANT SUMMER DAY EXPECTED ACROSS THE REGION TODAY
WITH SURFACE HIGH PRESSURE SLIPPING SOUTHEASTWARD INTO THE MID
MISSISSIPPI VALLEY BY THIS AFTERNOON. RETURN FLOW BEHIND THE HIGH
WILL BRING INCREASED SOUTHERLY FLOW...WHICH WILL BE GREATEST ACROSS
OUR WESTERN HALF. WINDS SHOULD BECOME BREEZY INTO THE JAMES VALLEY
AND WESTWARD. HIGHS WILL BE WARMER TODAY THAN IN PREVIOUS DAYS WITH
HIGHS MAINLY IN THE 80S...TO AROUND 90 IN SOUTH CENTRAL SOUTH
DAKOTA.
LOW LEVEL JET IS EXPECTED TO START KICKING IN THIS EVENING AND
OVERNIGHT ACROSS CENTRAL AND EASTERN PORTIONS OF THE FORECAST AREA.
THIS WILL BE COUPLED WITH A WEAK MID LEVEL WAVE WHICH TRACKS EAST
SOUTHEAST THROUGH THE FORECAST AREA. THIS SHOULD BE ENOUGH TO SQUEAK
OUT SOME ISOLATED THUNDERSTORMS...ALTHOUGH THE MEAGER MOISTURE COULD
WILL KEEP PRECIPITATION AMOUNTS WELL IN CHECK.
A BROAD CANADIAN UPPER TROUGH DIGGING INTO THE NORTHERN PLAINS WILL
DROP A FAIRLY POTENT COLD FRONT ACROSS THE NORTHERN PLAINS ON
WEDNESDAY. MIXY SOUTH SOUTHWEST WINDS AHEAD OF THE FRONT WILL USHER
IN THE WARMEST DAY OF THE WEEK AHEAD OF THE FRONT...WITH HIGHS IN
THE UPPER 80S TO MID 90S. THE FRONT WILL TRACK THROUGH THE FORECAST
AREA WEDNESDAY AFTERNOON AND EVENING...ACCOMPANIED BY A STRONG MID
LEVEL WAVE A FRONTOGENESIS. CAPPING SHOULD HOLD OFF INITIAL
CONVECTION IN OUR FAR WESTERN COUNTIES EARLY IN THE DAY...HOWEVER
WILL LIKELY SEE SCATTERED STORMS START FIRING EAST OF A YANKTON TO
BROOKINGS LINE IN THE LATE AFTERNOON AND BECOME MORE LIKELY ACROSS
NORTHWEST IOWA AND SOUTHWEST MINNESOTA IN THE EVENING HOURS AS
DAYTIME HEATING PEAKS AND THE 850 MB WAVE/FRONT DIGS INTO THE AREA.
STEEP LAPSE RATES APPROACHING 10C/KM...1500+ J/KG CAPE AND 40 KT
BULK SHEAR PER NAM FORECAST SOUNDINGS SUGGEST THE POTENTIAL FOR SOME
SEVERE STORMS WITH HAIL AND WIND CONCERNS...ALTHOUGH LOWER LEVEL
MOISTURE DOES APPEAR SOMEWHAT LACKING. WILL CONTINUE WITH LIKELY TO
CATEGORICAL POPS WEDNESDAY EVENING ACROSS NORTHWEST IOWA AND
SOUTHWEST MINNESOTA.
DRY NORTHWEST FLOW SETTLES IN FOR THE LATER HALF OF THE WEEK.
TEMPERATURES WILL BE QUITE A BIT COOLER ON THURSDAY WITH BREEZY
NORTHERLY WINDS ADVECTING IN SOME BELOW NORMAL TEMPERATURES AND
CLOUDS DECREASING THROUGH THE MORNING. HIGHS WILL LIKELY ONLY BE IN
THE 70S ON THURSDAY AND FRIDAY...BUT WILL BE ON A GRADUAL WARMING
TREND THROUGH THE WEEKEND. OVERALL CONDITIONS LOOK PRETTY DRY WITH
ONLY SOME MINOR MOISTURE STARVED WAVES TRACKING THROUGH THE PLAINS
IN THE NORTHWEST FLOW. GFS PAINTS SOME LIGHT POPS ACROSS THE AREA
AROUND THE SATURDAY TIME FRAME...WHICH IS NOT WELL SUPPORTED IN THE
OTHER MODELS. WILL CONTINUE TO LEAVE OUT ANY MENTION OF POPS BEYOND
EARLY THURSDAY WITH LITTLE CONFIDENCE IN THE TIMING AND TRACK OF ANY
MID LEVEL WAVE THAT DOES MAKE AN APPEARANCE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1143 PM CDT MON AUG 13 2012
.DISCUSSION...
UPDATED FOR 06Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 226 PM CDT MON AUG 13 2012/
MORNING CONVECTION HAS MOVED EAST OF THE MIDSOUTH AS EXPECTED
WITH PARTIAL SUNSHINE SPREADING OVER THE AREA FROM THE WEST.
MEANWHILE...A COLD FRONT IS PUSHING INTO NORTHEAST ARKANSAS AND
STRETCHES SOUTHWESTWARD INTO NORTHEAST TX. THE FRONT HAS MOVED
THROUGH WALNUT RIDGE ARKANSAS AND IS APPROACHING JONESBORO.
STILL THINK THERE IS A CHANCE OF SEVERE THUNDERSTORMS LATER THIS
AFTERNOON INTO THIS EVENING ALONG AND AHEAD OF THE COLD
FRONT...ALTHOUGH THE SITUATION IS NOT CLEAR CUT. WATER VAPOR IMAGERY
INDICATES THE MAIN UPPER LEVEL TROUGH IS MOVING EAST OF THE MIDSOUTH
WITH UPPER LEVEL SUPPORT NOW LIMITED ACROSS OUR FORECAST AREA. WATER
VAPOR IMAGERY IS ALSO SHOWING VERY DRY AIR ALOFT MOVING INTO OUR
FORECAST AREA. HOWEVER...VERY WARM AND UNSTABLE AIR IS PUSHING INTO
THE AREA AHEAD OF THE FRONT ON SOUTHWEST SURFACE WINDS. TEMPERATURES
IN NORTHEAST AND EAST CENTRAL AR ARE MOVING INTO THE LOWER 90S AND
SURFACE BASED CAPES HAVE INCREASED TO BETWEEN 2000 AND 2500 J/KG AND
LIFTED INDICES HAVE DECREASED TO ABOUT MINUS 6.
LATEST HIGH RESOLUTION RAPID REFRESH (HRRR) MODEL INDICATES THAT
SCATTERED SHOWERS AND THUNDERSTORMS WILL BEGIN TO FORM ALONG THE
COLD FRONT BY 3 OR 4 PM...THEN BECOME A LITTLE BETTER ORGANIZED AS
THE STORMS MOVE EAST OF THE MS RIVER BY LATE AFTERNOON AND EVENING.
MODELS CONTINUE TO INDICATE THE ATMOSPHERE WILL BECOME QUITE
UNSTABLE AHEAD OF THE FRONT WITH SURFACE BASED CAPES INCREASING TO
BETWEEN 32000 AND 4200 J/KG WITH LIFTED INDICES DECREASING TO MINUS
8. ALTHOUGH...THE HRRR MODEL INDICATES THE STORMS WILL STRUGGLE IN
COVERAGE WITH SUCH DRY AIR ALOFT LIMITING THE MOISTURE.
ALTHOUGH...THE DRY AIR ALOFT WILL ENHANCE THE DOWNDRAFT POTENTIAL
WITH DAMAGING STRAIGHT LINE WINDS POSSIBLE IN THE STRONGER STORMS.
LARGE HAIL IS ALSO POSSIBLE.
THE COLD FRONT IS FORECAST NEAR THE MS RIVER BY LATE
AFTERNOON...THEN WILL MOVE SOUTHEASTWARD THROUGH THE MIDSOUTH
TONIGHT. THINK THE SEVERE WEATHER THREAT WILL END BY LATE EVENING.
NOT MUCH CHANGE TO THE EARLIER FORECAST CONCERNING TUESDAY THROUGH
THE WEEKEND. HIGH PRESSURE AND DRIER AIR WILL SPREAD OVER THE
MIDSOUTH TUESDAY INTO WEDNESDAY ALLOWING FOR GOOD DIURNAL SPREADS IN
TEMPERATURES WITH RELATIVELY COOL NIGHTS AND VERY WARM AFTERNOONS.
A WARM FRONT IS FORECAST TO PUSH THROUGH THE MIDSOUTH THURSDAY WITH
VERY UNSTABLE AND MOIST AIR SPREADING BACK OVER THE AREA. THIS WILL
CAUSE A CHANCE OF SHOWERS AND THUNDERSTORMS. A COLD FRONT WILL
APPROACH FROM THE NORTHWEST THURSDAY NIGHT AND MOVE SLOWLY THROUGH
THE REGION FRIDAY INCREASING THE THREAT OF SHOWERS AND
THUNDERSTORMS. THERE WILL BE A LINGERING CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS EAST CENTRAL ARKANSAS AND NORTH MS SATURDAY BUT
OTHERWISE KEPT WITH A RAINFREE FORECAST FOR THE WEEKEND INTO NEXT
MONDAY. HOWEVER...THERE IS SOME QUESTION HOW FAR THE COLD FRONT WILL
SETTLE SOUTHWARD BECOMING STALLING...SO SOME CHANCE OF SHOWERS AND
THUNDERSTORMS COULD LINGER ACROSS EAST CENTRAL AR AND NORTH MS INTO
SUNDAY.
JCL
&&
.AVIATION...
06Z TAF CYCLE
SHRAS AND TSRAS HAVE PUSHED WELL EAST OF THE COLD FRONT THAT IS
SLOWLY MOVING ACROSS THE MIDSOUTH. AT 04Z THE FRONT WAS LOCATED
JUST EAST OF A KDYR-KMEM-KUTA LINE. GENERALLY VFR CONDS EXPECTED
OVER THE NEXT FEW HOURS THOUGH SOME LIGHT FOG IS POSSIBLE AT KMKL
AND KTUP. DRIER AIR HAS MOVED INTO KJBR AND IS FILTERING INTO
KMEM SO FOG THREAT IS MINIMAL AT THOSE LOCATIONS. EXPECT LOW
CLOUDS TO MOVE SOUTH AND DEVELOP ACROSS THE AREA LATE TONIGHT SO
ADDED TEMPOS FOR MVFR CIGS AT ALL SITES BTWN 14/11Z AND 14/15Z.
IFR CIGS POSSIBLE IN KMKL. CIGS WILL GRADUALLY LIFT AND BECOME VFR
DURING THE DAY. WINDS WILL GENERALLY BE LIGHT OVERNIGHT INCREASE
TO NORTH AT 7-10 TUESDAY MORNING.
SJM
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 69 88 68 93 / 10 0 10 10
MKL 65 86 59 90 / 30 10 10 10
JBR 63 87 62 92 / 10 0 10 10
TUP 70 89 65 91 / 50 10 10 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
653 PM CDT WED AUG 15 2012
.AVIATION...
ALTHOUGH ISLD TSRA WILL APPROACH KLBB TERMINAL FROM THE WEST
THROUGH 16/06Z...DO NOT ANTICIPATE ANY IMPACTS. ADDITIONAL ISOLD
SHRA/TSRA WILL BE POSSIBLE ACROSS W TX THU AFTN...BEYOND 16/18Z.
HOWEVER...ANY POTENTIAL IMPACTS WILL BE BRIEF AND WILL LIKELY NOT
FALL BELOW MVFR CAT. OTHERWISE...VFR CONDITIONS EXPECTED AT BOTH
KLBB AND KCDS THROUGH THE FORECAST PERIOD. JH
&&
.PREV DISCUSSION... /ISSUED 313 PM CDT WED AUG 15 2012/
SHORT TERM...
WE HAVE SOME MIXED SIGNALS REGARDING TSTM CHANCES LATE THIS
AFTERNOON AND EVENING. ON ONE HAND...LOW MOISTURE HAS INCREASED
MARKEDLY OVER YESTERDAY AND WE REMAIN UNDERNEATH A WEST-EAST MID-LVL
MOISTURE AXIS AS WELL. ON THE OTHER HAND...THE MOISTURE HAS DELAYED
HEATING AND THE AREA WAS STILL CAPPED AS OF 2 PM. NW FLOW CONTINUES
ALOFT AND WATER VAPOR IMAGERY SHOWS THE NEXT SHORTWAVE MOVING INTO
NRN NM AT THIS TIME....WHICH IS HELPING TO INITIATE STORMS ALL ALONG
THE NEW MEXICO MTNS. THERE IS ALSO SOME CU DEVELOPMENT IN THE
EAST TO SOUTH-CENTRAL TX PANHANDLE ALONG A SFC TROUGH AND AS THE CAP
WEAKENS WE COULD SEE SOME STORMS DEVELOP ALONG THIS TROUGH INTO
THE FAR SRN PANHANDLE...POSSIBLY SWISHER AND BRISCOE COUNTIES.
FINALLY...WE HAVE ANOTHER WEAK SFC TROUGH NEAR THE TX-NM BORDER
WHICH COULD ALSO BE THE FOCUS FOR SOME STORM DEVELOPMENT WEST OF
HIGHWAY 214. SO WITH ALL THIS...WE HAVE A SLGT CHANCE GOING ACROSS
THE ENTIRE FA THIS AFTERNOON FOR THE POSSIBILITY OF SOME LOCAL
DEVELOPMENT. BUT WE EXPECT THE MAIN SHOW SO TO SPEAK TO BE LATER
THIS EVENING AS A BROKEN LINE/LOOSE COMPLEX OF STORMS MOVES
ROUGHLY E-SEWD OUT OF EASTERN NEW MEXICO....ACROSS THE SPLNS AND
POSSIBLY INTO THE ROLLING PLAINS TONIGHT. THE HRRR HAS BEEN RATHER
CONSISTENT IN THIS DEPICTION...WHILE MUCH OF THE OTHER GUIDANCE
WEAKENS THE ACTIVITY AS IT MOVES EAST. WITH THE UPPER WAVE
PROVIDING SOME BACKGROUND ASCENT AND A 30 TO 40 KT SRLY LLJ WE
CURRENTLY ANTICIPATE THE ACTIVITY MAKING IT AT LEAST INTO THE
CENTRAL SPLNS AND FAR SRN PANHANDLE. DEEP LAYER SHEAR IS CURRENTLY
VERY WEAK...BUT WILL INCREASE THIS EVENING AS THE LLJ CRANKS UP.
INSTABILITY IS ALSO ON THE WEAK TO MODERATE SIDE...HIGHEST
POSITIONED ACROSS THE NORTH. THIS ENVIRONMENT SHOULD SUPPORT THE
THREAT FOR ISOLATED STRONG TO SEVERE WIND GUSTS...WITH THE DEEPER
MOISTURE SUPPORTING STRONGER COLD POOLS AND BETTER RAINFALL
POTENTIAL AS WELL.
WHILE WE SHOULD SEE MOST ACTIVITY WANE IN THE EARLY MORNING
HRS...CONTINUED BROAD UPWARD MOTION IN NW FLOW WILL KEEP A CHANCE OF
SOME ISOLD SHOWERS/TSTMS GOING THROUGH THU MORNING. THEN...A COLD
FRONT IS EXPECTED TO MOVE INTO OUT NRN ZONES LATE THU
MORNING...LIKELY STALLING OUT SOMEWHERE ACROSS THE FAR SRN PANHANDLE
AND NW SPLNS BY MIDDAY OR EARLY AFTERNOON. THIS FRONT SHOULD ABLY SERVE
AS A FOCUS FOR CONVECTIVE INITIATION THURSDAY AFTERNOON. TEMPS MAY
NOT MAKE IT OUT OF THE 80S NORTH OF THE FRONT...WHILE WE EXPECT
HIGHS TO ONCE AGAIN CLIMB INTO THE UPPER 90S TO THE SOUTH OF THE
FRONT. SOUTH OF THE FRONT...THERE WILL BE SOME DOWNBURST POTENTIAL
FROM THE TSTM ACTIVITY....WHILE NORTH OF THE FRONT RAINFALL CHANCES
WILL BE BETTER.
LONG TERM...
THURSDAY NIGHT THRU SATURDAY...
THE COLD FRONT FROM EARLIER IN THE DAY THURSDAY SHOULD BE STALLED
SOMEWHERE IN THE NORTHERN HALF OF THE CWA BY THURSDAY EVENING. A
GENERAL WEAKNESS IN WINDS ALOFT MAY ACT TO KEEP CONVECTION FOCUSED
RELATIVELY CLOSE TO THE BOUNDARY...OR PERHAPS EVEN NORTH OF THE
FRONT AS ISENTROPIC LIFT IS PROGGED TO AMPLIFY OVERNIGHT AS PER THE
GFS. OPTED TO THEREFORE TIGHTEN THE POP GRADIENT THU NIGHT FROM
NORTH-TO-SOUTH TO REFLECT THIS THINKING. BY FRIDAY...ATTENTION WILL
TURN MORE TO THE SUBTROPICAL PLUME OF MOISTURE CURRENTLY HUGGING THE
WRN COAST OF MEXICO. SOME OF THIS MOISTURE WILL SPREAD NORTH BEFORE
CURLING EASTWARD INTO WEST TX WITHIN A REGION OF LOWERED HEIGHTS
BETWEEN TWO 700MB HIGH CENTERS. PROVIDED THE OSCILLATING FRONTAL
BOUNDARY REMAINS IN THE CWA...LIKELY POPS MAY BE WARRANTED FRI AFTN.
HOWEVER...THIS STRATEGY IS CLOUDED WITH DOUBT AS THE NAM NOW
RETREATS THE BOUNDARY WELL NORTH INTO THE PANHANDLE WHILE PUSHING
HIGHS AREA WIDE INTO THE 90S. NOT YET WILLING TO BREAK CONTINUITY AS
THE NAM`S FRONTAL SOLUTION SEEMS TOO AGGRESSIVE...SO WILL SIDE WITH
THE GFS FAVORING A MORE SOUTHERLY BOUNDARY POSITION. A LULL IN PRECIP
CHANCES MAY VERY WELL DEVELOP FRI EVENING BEFORE DEEPER ASCENT
ARRIVES LATE IN THE NIGHT AND EARLY SAT COURTESY OF A CYCLONICALLY
CURVED JET STREAK DIVING THROUGH THE SOUTHERN GREAT PLAINS. ENHANCED
UPPER DIVERGENCE IN THE EXIT REGION OF THIS 2-CELL MAXIMA WOULD TEND
TO FAVOR THE BEST POPS AFTER MIDNIGHT PRIMARILY ACROSS THE NERN 1/3
OF THE CWA BEFORE EXPANDING OVER THE REMAINDER OF THE AREA SAT
MORNING AS THE BASE OF AN UPPER TROUGH IN NWLY FLOW DRAWS CLOSER.
GIVEN THIS PATTERN IN THE PRESENCE OF PWATS AROUND 1.5 INCHES...WE
COULD CERTAINLY RATCHET POPS INTO THE LIKELY REALM...BUT WILL SETTLE
FOR HIGH CHANCE AT THIS TIME AS THIS WINDOW IS STILL FIVE PERIODS
OUT AND SUBJECT TO CHANGE.
GFS AND ECMWF ARE IN A SURPRISINGLY GOOD AGREEMENT...FOR THE MOST PART...
FOR THE PERIODS SAT THRU TUES. BOTH SEEM TO BE IN AN AGREEMENT WITH
A STALLED FRONT DRAPED FROM THE NC COAST TO THE TX PANHANDLE.
DEWPOINTS WILL BE FAIRLY HIGH...AROUND THE LOWER 60S. THIS COUPLED
WITH UPPER LEVEL DIVERGENCE SHOULD ALLOW WITH SOME PRECIP. I HAVE
BUMPED UP THE POPS JUST A BIT FOR SAT EVENING. THE FRONT SHOULD MOVE
OUT OF THE AREA BY SUN MORNING/EARLY AFTERNOON. HIGHS FOR SAT SHOULD
BE IN THE UPPER 80S. BEYOND THEN THE MODELS VARY IN PRECIP CHANCES.
THE GFS KEEPS PRECIP SOMEWHAT SUPPRESSED AND LOCALIZED OVER THE
PANHANDLE WITH THE INFLUENCE OF AN UPPER LEVEL HIGH WHILE THE 12Z
ECMWF HAS MORE WIDESPREAD COVERAGE DUE TO THE INFLUENCE OF A
SHORTWAVE TROF OVER KS. HAVE KEPT POPS ON THE DOWN LOW AT THE
CURRENT TIME DUE TO UNCERTAINTY BUT DO HAVE A MENTION OF THEM.
LATER IN THE PERIOD AROUND WED THE 12Z GFS AND THE 00Z ECMWF
DIFFER...ESPECIALLY NEAR THE SURFACE. THE GFS IS TRYING TO DEVELOP A
1001 MB LOW IN EASTERN MT WITH A SURFACE TROF DRAPED DOWN TO THE OK
PANHANDLE WED MORNING AND DEEPENS IT TO A 997 MB LOW BY THUR
MORNING...WHILE PUSHING A DRYLINE INTO THE WESTERN PANHANDLE. THE
ECMWF HAS A 1022 MB HIGH OVER MT AND SINKS DOWN TO CO BY THUR
MORNING. HOWEVER...THE NEW 12Z ECMWF HAS COME MORE IN LINE WITH THE
12Z GFS EXCEPT WITH ABOUT A 6 HOUR TIMING DELAY. EITHER WAY...UPPER
LEVEL RIDGING APPEARS TO BE THE NAME OF THE GAME OVER WESTERN TEXAS
AND THAT SHOULD HELP SUPPRESS CONVECTION AND KEEP TEMPS AT THE SURFACE
WARM. ALDRICH
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 65 86 63 85 65 / 30 40 40 40 40
TULIA 67 88 65 86 65 / 30 40 40 40 50
PLAINVIEW 68 90 65 86 66 / 30 30 40 40 50
LEVELLAND 68 93 67 88 67 / 30 30 20 40 40
LUBBOCK 70 93 68 88 68 / 30 30 20 40 40
DENVER CITY 69 94 68 88 68 / 20 20 20 30 30
BROWNFIELD 67 94 68 89 68 / 20 20 20 30 40
CHILDRESS 72 97 69 90 69 / 20 30 40 40 50
SPUR 70 96 70 90 71 / 20 20 20 40 50
ASPERMONT 71 100 72 92 71 / 20 20 20 30 50
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
02
AREA FORECAST DISCUSSION...UPDATED
NWS BLACKSBURG VA
1019 PM EDT WED AUG 15 2012
.SYNOPSIS...
WEAK HIGH PRESSURE BUILDS IN OVERNIGHT ALLOWING FOR DRIER WEATHER
INTO THURSDAY. ANOTHER FRONT IMPACTS THE REGION FRIDAY INTO THE
WEEKEND WITH A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
FRIDAY THROUGH SATURDAY ALONG WITH SEASONABLY MILD TEMPERATURES.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 1010 PM EDT WEDNESDAY...
LOOKS LIKE THE LAST OF THE SHRA FINALLY FADING ACROSS THE EAST
WITH PERHAPS STILL AN ISOLATED SHRA TO AFFECT LYNCHBURG BEFORE
PRECIP ENDS WITH LOSS OF HEATING/INSTABILITY. HOWEVER SOME LOW
CLOUDS CONTINUE TO LINGER EAST OF THE BLUE RIDGE IN VIRGINIA AND
REMAIN BANKED UP WITH UPSLOPE FLOW AROUND BLUEFIELD SO UPDATING TO
INCLUDE MORE CLOUDS EARLY ON. OTRW ARRIVAL OF VERY DRY AIR ALOFT
PER VAPOR LOOP/EVENING RAOBS IN CONJUNCTION WITH HIGH PRESSURE
BUILDING IN FROM THE WEST SHOULD MAKE FOR MAINLY CLEAR SKIES AND
MORE COMFORTABLE TEMPS AFTER MIDNIGHT AS DRIER AIR SEEPS IN. SOME
FOG AGAIN LIKELY ESPCLY VALLEYS AND WHERE SPOTTY HEAVIER DOWNPOURS
OCCURRED EARLIER SO TWEAKING COVERAGE A LITTLE. BASICALLY LEAVING
TEMPS CLOSE TO PREVIOUS EXCEPT NUDGING UP SLIGHTLY IN THE EAST
WHERE DRIER AIR WILL BE SLOWER TO ARRIVE. OTRW LOWS MAINLY IN THE
COOLER 50S MOUNTAINS TO 60-65 EAST ON TRACK.
AS OF 605 PM EDT WEDNESDAY...
EVENING UPDATE TO LOWER POPS ACROSS THE FAR SOUTH AS DEEPER
CONVECTION ACROSS CENTRAL NC HAS TAKEN BETTER LIFT FARTHER SOUTH.
HOWEVER BUMPED UP COVERAGE A BIT OVER THE NE PER LEFTOVER BAND OF
SHRA/TSRA HEADING DOWN JUST EAST OF THE BLUE RIDGE AND OVER THE NW
JUST AHEAD OF THE ACTUAL DEWPOINT FRONT. APPEARS ENOUGH
INSTABILITY OVER THE NE TO PROMOTE SOME ISOLATED TSRA SO KEPT
MENTION THERE WITH MAINLY SHRA ELSW. THIS BOUNDARY SHOULD PUSH
THRU THE MOUNTAINS OVER THE NEXT FEW HOURS AND THE REST OF THE CWA
THIS EVENING BEHIND THE PASSING UPPER VORT. GOOD SUBSIDENCE BEHIND
THIS FEATURE SHOULD BRING AN END TO ANY REMAINING SHRA WITH LOSS
OF HEATING SO ONLY ISOLATED POPS AT BEST ELSW THIS EVENING.
PREVIOUS DISCUSSION AS OF 325 PM EDT WEDNESDAY...
MAIN SHORTWAVE IS STARTING TO MOVE INTO NRN VA ATTM...WITH PIECES OF
VORT ENERGY OCCURRING ALONG THE BACK EDGE OF THE DEEPER MOISTURE
ACROSS THE SOUTHERN APPALACHIANS INTO SRN WV. STILL APPEARS THE NEAR
TERM MESOSCALE MODELS HOLD CONVECTION THAT IS OCCURRING OVER THE
CENTRAL PORTION OF OUR FORECAST AREA EAST INTO THE PIEDMONT FOR LATE
AFTERNOON. FOLLOWED THE LATEST HRRR EXCEPT SLOWED ITS TIMING DOWN
GIVEN SPEED OF ECHOES ON RADAR BEING SLOWER. ATTM...THINK WILL SEE
THUNDER THREAT PUSHING EAST OF THE BLUE RIDGE SOON....THEN SHOULD
EXPECT SHOWERS TO WIND DOWN AND DISSIPATE AFTER 00Z. SOME CLEARING
AHEAD OF THE VORT LOBE MAY CREATE ENOUGH INSTABILITY THAT A FEW
CELLS COULD BE STRONG TO EVEN SEVERE WITH DAMAGING WINDS POSSIBLE.
CURRENT ANALYSIS SUGGESTS THE GREATEST POTENTIAL FOR THIS WILL BE
SOUTHEAST OF OUR CWA...BUT THOSE AREAS SOUTH OF HIGHWAY 58 FROM
DANVILLE TO SOUTH BOSTON INTO NC MAY BE IN A BETTER ENVIRONMENT FOR
THIS.
AFTER THE ACTIVITY WANES TONIGHT...SKIES SHOULD CLEAR AND SOME FOG
WILL FORM ESPECIALLY WHERE IT RAINED...BUT OVERALL KEPT IT IN THE
MTNS. WILL SEE JUST ENOUGH DRY AIR TO LOWER TEMPS SOME
TONIGHT...CLOSER TO LOCAL MOS WITH MID 50S MTNS TO LOWER 60S
SOUTHEAST.
FLOW WILL BACK AGAIN TO THE SOUTHWEST THU AFTERNOON WITH RISING
HEIGHTS. HIGHS WILL BE WARM ESPECIALLY EAST WITH NEAR 90...WHILE THE
MTNS STAY IN THE LOWER 80S.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 350 PM WEDNESDAY...
UPPER AIR PATTERN BECOMES AMPLIFIED FOR THE WEEKS END WITH RIDGE
OVER THE ROCKIES AND TROUGH IN THE EAST. DEEPER TROUGHING IN THE
EAST WILL BE PRECEDED BY WEAK RIDGING THURSDAY NIGHT AND EARLY
FRIDAY AHEAD OF SURFACE COLD FRONT THAT WILL BE MOVING THROUGH THE
OHIO VALLEY. WITH 85H TEMPS +18 DEG C...SHOULD SEE SPIKE IN
TEMPERATURE PRIOR TO FROPA FRIDAY EVENING. CLOUD INCREASE AHEAD OF
FRONT SHOULD KEEP TEMPS IN THE MTNS IN THE 70S...BUT NEAR FULL
INSOLATION EAST OF MTNS WILL LIKELY PERMIT TEMPS TO TEST 90 EAST
OF THE BLUE RIDGE. HIGHEST POPS FRIDAY ANTICIPATED IN THE
MTNS...SHRA/TSRA DEVELOPING IN ADV OF FRONT AND MOVING ACROSS THE CWA
DURING THE LATE AFTERNOON AND EVENING.
MODELS SLOW PROGRESSION OF FRONT AS IT CROSSES THE CWA...THUS CLOUDS
AND PRECIP THREAT MAY LINGER INTO SATURDAY. NOT OVERLY EXCITED
ABOUT INSTABILITY SATURDAY PER LINGERING CLOUD COVER...THUS THINK
ANY PRECIP SATURDAY WOULD BE IN THE FORM OF SHOWERS AND LITTLE OR NO
THUNDER. FRONT IS FCST TO DISSIPATE OVER OR JUST SOUTH OF THE AREA
SATURDAY NIGHT...AMOUNT OF CLEARING DEPENDENT ON FRONTAL REMNANTS.
TEMPERATURES SATURDAY WILL BE TEMPERED BY CLOUD COVER...L-M 70S
MTS...LOWER 80S PIEDMONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 350 PM WEDNESDAY...
UPPER LEVEL TROUGH SETS UP SHOP OVER THE ERN CONUS FOR NEXT WEEK.
FLOW ALOFT REMAINS CYCLONIC WITH EMBEDDED SHORT WAVE ENERGY HELPING
TO KEEP THE FLOW AMPLIFIED. PRESENCE OF THE TROUGH SUGGESTS TEMPS
WILL RUN BLO MEDIAN. AS FOR PRECIP...A LOT WILL DEPEND ON THE
AMOUNT OF RETURN FLOW THAT CAN DEVELOP AND TIMING OF ANY SHORT WAVE
ENERGY. FOR NOW WILL FOCUS HIGHEST POPS VCNTY OF MTNS WHERE LOW
LEVEL CONVERGENCE WILL BE GREATEST...ALTHOUGH COOLER THAN NORMAL
TEMPS SUGGESTS INSTABILITY WILL BE MAINLY DIURNALLY DRIVEN.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
AS OF 650 PM EDT WEDNESDAY...
FEW SHOWERS REMAIN ACROSS THE NE BUT EXPECT FURTHER DISSIPATION WITH
LOSS OF HEATING SO THINKING MAY BE ABLE TO RUN WITHOUT ANY PRECIP
MENTION TO INIT AT MOST TAF SITES OUTSIDE OF KLYH THIS EVENING.
WAVE EXITS BY MIDNIGHT WITH DECENT SUBSIDENCE SPILLING EAST
ALLOWING FOR CLEARING SKIES AND SLOWLY FALLING DEWPOINTS. HOWEVER
APPEARS ENOUGH LOW LEVEL MOISTURE MAY LINGER LONG ENOUGH TO CAUSE
FOG FORMATION IN THE VALLEYS AND IN SPOTS NEAR WHERE EARLIER RAIN
OCCURRED ESPCLY KDAN. LOW CIGS MAY ALSO BANK UP AROUND KBLF
OVERNIGHT GIVEN WEAK NW FLOW WITH MVFR/IFR FOG LIKELY. OTRW
THINKING LIFR IN FOG/STRATUS AT KLWB AND MAINLY MVFR KBCB/KDAN AND
PERHAPS KLYH.
ANY FOG AND/OR LOW CLOUDS SHOULD HAVE ERODED BY MID MORNING
THURSDAY WITH HIGH PRESSURE PROVIDING FOR VFR UNDER FEW/SCTD CU
INTO THE AFTERNOON UNDER LIGHT WINDS.
ASIDE FROM SOME LATE NIGHT FOG AT LWB/BCB ANTICIPATE THE NEXT
THREAT FOR SUB VFR TO COME WITH A FRONT FRIDAY INTO SATURDAY. THE
FRONT SLOWS AND LINGERS ACROSS THE CAROLINAS THROUGH THE WEEKEND
SUCH THAT THE THREAT OF SHOWERS MAY OCCUR ACROSS SOUTHERN
SECTIONS...WIH SOME MVFR POSSIBLE. THE FRONT WILL BE MOVING SLOWLY
EAST BY MONDAY AS HIGH PRESSURE WORKS IN FROM THE OHIO VALLEY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...JH/WP
SHORT TERM...PM
LONG TERM...PM
AVIATION...JH/RAB/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
901 PM EDT WED AUG 15 2012
.SYNOPSIS...
WEAK HIGH PRESSURE BUILDS IN OVERNIGHT ALLOWING FOR DRIER WEATHER
INTO THURSDAY. ANOTHER FRONT IMPACTS THE REGION FRIDAY INTO THE
WEEKEND WITH A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
FRIDAY THROUGH SATURDAY ALONG WITH SEASONABLY MILD TEMPERATURES.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 845 PM EDT WEDNESDAY...
LOOKS LIKE THE LAST OF THE SHRA FINALLY FADING ACROSS THE EAST
WITH PERHAPS STILL AN ISOLATED SHRA TO AFFECT LYNCHBURG BEFORE
PRECIP ENDS WITH LOSS OF HEATING/INSTABILITY. OTRW ARRIVAL OF
VERY DRY AIR ALOFT PER VAPOR LOOP/EVENING RAOBS IN CONJUNCTION
WITH HIGH PRESSURE BUILDING IN FROM THE WEST SHOULD MAKE FOR
MAINLY CLEAR SKIES AND MORE COMFORTABLE TEMPS OVERNIGHT AS DRIER
AIR SEEPS IN. SOME FOG AGAIN LIKELY ESPCLY VALLEYS AND WHERE SPOTTY
HEAVIER DOWNPOURS OCCURRED EARLIER SO TWEAKING COVERAGE A LITTLE.
BASICALLY LEAVING TEMPS CLOSE TO PREVIOUS EXCEPT NUDGING UP
SLIGHTLY IN THE EAST WHERE DRIER AIR WILL BE SLOWER TO ARRIVE.
OTRW LOWS MAINLY IN THE COOLER 50S MOUNTAINS TO 60-65 EAST ON
TRACK.
AS OF 605 PM EDT WEDNESDAY...
EVENING UPDATE TO LOWER POPS ACROSS THE FAR SOUTH AS DEEPER
CONVECTION ACROSS CENTRAL NC HAS TAKEN BETTER LIFT FARTHER SOUTH.
HOWEVER BUMPED UP COVERAGE A BIT OVER THE NE PER LEFTOVER BAND OF
SHRA/TSRA HEADING DOWN JUST EAST OF THE BLUE RIDGE AND OVER THE NW
JUST AHEAD OF THE ACTUAL DEWPOINT FRONT. APPEARS ENOUGH
INSTABILITY OVER THE NE TO PROMOTE SOME ISOLATED TSRA SO KEPT
MENTION THERE WITH MAINLY SHRA ELSW. THIS BOUNDARY SHOULD PUSH
THRU THE MOUNTAINS OVER THE NEXT FEW HOURS AND THE REST OF THE CWA
THIS EVENING BEHIND THE PASSING UPPER VORT. GOOD SUBSIDENCE BEHIND
THIS FEATURE SHOULD BRING AN END TO ANY REMAINING SHRA WITH LOSS
OF HEATING SO ONLY ISOLATED POPS AT BEST ELSW THIS EVENING.
PREVIOUS DISCUSSION AS OF 325 PM EDT WEDNESDAY...
MAIN SHORTWAVE IS STARTING TO MOVE INTO NRN VA ATTM...WITH PIECES OF
VORT ENERGY OCCURRING ALONG THE BACK EDGE OF THE DEEPER MOISTURE
ACROSS THE SOUTHERN APPALACHIANS INTO SRN WV. STILL APPEARS THE NEAR
TERM MESOSCALE MODELS HOLD CONVECTION THAT IS OCCURRING OVER THE
CENTRAL PORTION OF OUR FORECAST AREA EAST INTO THE PIEDMONT FOR LATE
AFTERNOON. FOLLOWED THE LATEST HRRR EXCEPT SLOWED ITS TIMING DOWN
GIVEN SPEED OF ECHOES ON RADAR BEING SLOWER. ATTM...THINK WILL SEE
THUNDER THREAT PUSHING EAST OF THE BLUE RIDGE SOON....THEN SHOULD
EXPECT SHOWERS TO WIND DOWN AND DISSIPATE AFTER 00Z. SOME CLEARING
AHEAD OF THE VORT LOBE MAY CREATE ENOUGH INSTABILITY THAT A FEW
CELLS COULD BE STRONG TO EVEN SEVERE WITH DAMAGING WINDS POSSIBLE.
CURRENT ANALYSIS SUGGESTS THE GREATEST POTENTIAL FOR THIS WILL BE
SOUTHEAST OF OUR CWA...BUT THOSE AREAS SOUTH OF HIGHWAY 58 FROM
DANVILLE TO SOUTH BOSTON INTO NC MAY BE IN A BETTER ENVIRONMENT FOR
THIS.
AFTER THE ACTIVITY WANES TONIGHT...SKIES SHOULD CLEAR AND SOME FOG
WILL FORM ESPECIALLY WHERE IT RAINED...BUT OVERALL KEPT IT IN THE
MTNS. WILL SEE JUST ENOUGH DRY AIR TO LOWER TEMPS SOME
TONIGHT...CLOSER TO LOCAL MOS WITH MID 50S MTNS TO LOWER 60S
SOUTHEAST.
FLOW WILL BACK AGAIN TO THE SOUTHWEST THU AFTERNOON WITH RISING
HEIGHTS. HIGHS WILL BE WARM ESPECIALLY EAST WITH NEAR 90...WHILE THE
MTNS STAY IN THE LOWER 80S.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 350 PM WEDNESDAY...
UPPER AIR PATTERN BECOMES AMPLIFIED FOR THE WEEKS END WITH RIDGE
OVER THE ROCKIES AND TROUGH IN THE EAST. DEEPER TROUGHING IN THE
EAST WILL BE PRECEDED BY WEAK RIDGING THURSDAY NIGHT AND EARLY
FRIDAY AHEAD OF SURFACE COLD FRONT THAT WILL BE MOVING THROUGH THE
OHIO VALLEY. WITH 85H TEMPS +18 DEG C...SHOULD SEE SPIKE IN
TEMPERATURE PRIOR TO FROPA FRIDAY EVENING. CLOUD INCREASE AHEAD OF
FRONT SHOULD KEEP TEMPS IN THE MTNS IN THE 70S...BUT NEAR FULL
INSOLATION EAST OF MTNS WILL LIKELY PERMIT TEMPS TO TEST 90 EAST
OF THE BLUE RIDGE. HIGHEST POPS FRIDAY ANTICIPATED IN THE
MTNS...SHRA/TSRA DEVELOPING IN ADV OF FRONT AND MOVING ACROSS THE CWA
DURING THE LATE AFTERNOON AND EVENING.
MODELS SLOW PROGRESSION OF FRONT AS IT CROSSES THE CWA...THUS CLOUDS
AND PRECIP THREAT MAY LINGER INTO SATURDAY. NOT OVERLY EXCITED
ABOUT INSTABILITY SATURDAY PER LINGERING CLOUD COVER...THUS THINK
ANY PRECIP SATURDAY WOULD BE IN THE FORM OF SHOWERS AND LITTLE OR NO
THUNDER. FRONT IS FCST TO DISSIPATE OVER OR JUST SOUTH OF THE AREA
SATURDAY NIGHT...AMOUNT OF CLEARING DEPENDENT ON FRONTAL REMNANTS.
TEMPERATURES SATURDAY WILL BE TEMPERED BY CLOUD COVER...L-M 70S
MTS...LOWER 80S PIEDMONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 350 PM WEDNESDAY...
UPPER LEVEL TROUGH SETS UP SHOP OVER THE ERN CONUS FOR NEXT WEEK.
FLOW ALOFT REMAINS CYCLONIC WITH EMBEDDED SHORT WAVE ENERGY HELPING
TO KEEP THE FLOW AMPLIFIED. PRESENCE OF THE TROUGH SUGGESTS TEMPS
WILL RUN BLO MEDIAN. AS FOR PRECIP...A LOT WILL DEPEND ON THE
AMOUNT OF RETURN FLOW THAT CAN DEVELOP AND TIMING OF ANY SHORT WAVE
ENERGY. FOR NOW WILL FOCUS HIGHEST POPS VCNTY OF MTNS WHERE LOW
LEVEL CONVERGENCE WILL BE GREATEST...ALTHOUGH COOLER THAN NORMAL
TEMPS SUGGESTS INSTABILITY WILL BE MAINLY DIURNALLY DRIVEN.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
AS OF 650 PM EDT WEDNESDAY...
FEW SHOWERS REMAIN ACROSS THE NE BUT EXPECT FURTHER DISSIPATION WITH
LOSS OF HEATING SO THINKING MAY BE ABLE TO RUN WITHOUT ANY PRECIP
MENTION TO INIT AT MOST TAF SITES OUTSIDE OF KLYH THIS EVENING.
WAVE EXITS BY MIDNIGHT WITH DECENT SUBSIDENCE SPILLING EAST
ALLOWING FOR CLEARING SKIES AND SLOWLY FALLING DEWPOINTS. HOWEVER
APPEARS ENOUGH LOW LEVEL MOISTURE MAY LINGER LONG ENOUGH TO CAUSE
FOG FORMATION IN THE VALLEYS AND IN SPOTS NEAR WHERE EARLIER RAIN
OCCURRED ESPCLY KDAN. LOW CIGS MAY ALSO BANK UP AROUND KBLF
OVERNIGHT GIVEN WEAK NW FLOW WITH MVFR/IFR FOG LIKELY. OTRW
THINKING LIFR IN FOG/STRATUS AT KLWB AND MAINLY MVFR KBCB/KDAN AND
PERHAPS KLYH.
ANY FOG AND/OR LOW CLOUDS SHOULD HAVE ERODED BY MID MORNING
THURSDAY WITH HIGH PRESSURE PROVIDING FOR VFR UNDER FEW/SCTD CU
INTO THE AFTERNOON UNDER LIGHT WINDS.
ASIDE FROM SOME LATE NIGHT FOG AT LWB/BCB ANTICIPATE THE NEXT
THREAT FOR SUB VFR TO COME WITH A FRONT FRIDAY INTO SATURDAY. THE
FRONT SLOWS AND LINGERS ACROSS THE CAROLINAS THROUGH THE WEEKEND
SUCH THAT THE THREAT OF SHOWERS MAY OCCUR ACROSS SOUTHERN
SECTIONS...WIH SOME MVFR POSSIBLE. THE FRONT WILL BE MOVING SLOWLY
EAST BY MONDAY AS HIGH PRESSURE WORKS IN FROM THE OHIO VALLEY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...JH/WP
SHORT TERM...PM
LONG TERM...PM
AVIATION...JH/RAB/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
714 PM EDT WED AUG 15 2012
.SYNOPSIS...
WEAK HIGH PRESSURE BUILDS IN BEHIND THE DEPARTING SHORTWAVE
TONIGHT. ANOTHER FRONT IMPACTS THE REGION FRIDAY INTO THE WEEKEND
WITH A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
FRIDAY THROUGH SATURDAY ALONG WITH SEASONABLY MILD TEMPERATURES.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 605 PM EDT WEDNESDAY...
EVENING UPDATE TO LOWER POPS ACROSS THE FAR SOUTH AS DEEPER
CONVECTION ACROSS CENTRAL NC HAS TAKEN BETTER LIFT FARTHER SOUTH.
HOWEVER BUMPED UP COVERAGE A BIT OVER THE NE PER LEFTOVER BAND OF
SHRA/TSRA HEADING DOWN JUST EAST OF THE BLUE RIDGE AND OVER THE NW
JUST AHEAD OF THE ACTUAL DEWPOINT FRONT. APPEARS ENOUGH
INSTABILITY OVER THE NE TO PROMOTE SOME ISOLATED TSRA SO KEPT
MENTION THERE WITH MAINLY SHRA ELSW. THIS BOUNDARY SHOULD PUSH
THRU THE MOUNTAINS OVER THE NEXT FEW HOURS AND THE REST OF THE CWA
THIS EVENING BEHIND THE PASSING UPPER VORT. GOOD SUBSIDENCE BEHIND
THIS FEATURE SHOULD BRING AN END TO ANY REMAINING SHRA WITH LOSS
OF HEATING SO ONLY ISOLATED POPS AT BEST ELSW THIS EVENING.
PREVIOUS DISCUSSION AS OF 325 PM EDT WEDNESDAY...
MAIN SHORTWAVE IS STARTING TO MOVE INTO NRN VA ATTM...WITH PIECES OF
VORT ENERGY OCCURRING ALONG THE BACK EDGE OF THE DEEPER MOISTURE
ACROSS THE SOUTHERN APPALACHIANS INTO SRN WV. STILL APPEARS THE NEAR
TERM MESOSCALE MODELS HOLD CONVECTION THAT IS OCCURRING OVER THE
CENTRAL PORTION OF OUR FORECAST AREA EAST INTO THE PIEDMONT FOR LATE
AFTERNOON. FOLLOWED THE LATEST HRRR EXCEPT SLOWED ITS TIMING DOWN
GIVEN SPEED OF ECHOES ON RADAR BEING SLOWER. ATTM...THINK WILL SEE
THUNDER THREAT PUSHING EAST OF THE BLUE RIDGE SOON....THEN SHOULD
EXPECT SHOWERS TO WIND DOWN AND DISSIPATE AFTER 00Z. SOME CLEARING
AHEAD OF THE VORT LOBE MAY CREATE ENOUGH INSTABILITY THAT A FEW
CELLS COULD BE STRONG TO EVEN SEVERE WITH DAMAGING WINDS POSSIBLE.
CURRENT ANALYSIS SUGGESTS THE GREATEST POTENTIAL FOR THIS WILL BE
SOUTHEAST OF OUR CWA...BUT THOSE AREAS SOUTH OF HIGHWAY 58 FROM
DANVILLE TO SOUTH BOSTON INTO NC MAY BE IN A BETTER ENVIRONMENT FOR
THIS.
AFTER THE ACTIVITY WANES TONIGHT...SKIES SHOULD CLEAR AND SOME FOG
WILL FORM ESPECIALLY WHERE IT RAINED...BUT OVERALL KEPT IT IN THE
MTNS. WILL SEE JUST ENOUGH DRY AIR TO LOWER TEMPS SOME
TONIGHT...CLOSER TO LOCAL MOS WITH MID 50S MTNS TO LOWER 60S
SOUTHEAST.
FLOW WILL BACK AGAIN TO THE SOUTHWEST THU AFTERNOON WITH RISING
HEIGHTS. HIGHS WILL BE WARM ESPECIALLY EAST WITH NEAR 90...WHILE THE
MTNS STAY IN THE LOWER 80S.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 350 PM WEDNESDAY...
UPPER AIR PATTERN BECOMES AMPLIFIED FOR THE WEEKS END WITH RIDGE
OVER THE ROCKIES AND TROUGH IN THE EAST. DEEPER TROUGHING IN THE
EAST WILL BE PRECEDED BY WEAK RIDGING THURSDAY NIGHT AND EARLY
FRIDAY AHEAD OF SURFACE COLD FRONT THAT WILL BE MOVING THROUGH THE
OHIO VALLEY. WITH 85H TEMPS +18 DEG C...SHOULD SEE SPIKE IN
TEMPERATURE PRIOR TO FROPA FRIDAY EVENING. CLOUD INCREASE AHEAD OF
FRONT SHOULD KEEP TEMPS IN THE MTNS IN THE 70S...BUT NEAR FULL
INSOLATION EAST OF MTNS WILL LIKELY PERMIT TEMPS TO TEST 90 EAST
OF THE BLUE RIDGE. HIGHEST POPS FRIDAY ANTICIPATED IN THE
MTNS...SHRA/TSRA DEVELOPING IN ADV OF FRONT AND MOVING ACROSS THE CWA
DURING THE LATE AFTERNOON AND EVENING.
MODELS SLOW PROGRESSION OF FRONT AS IT CROSSES THE CWA...THUS CLOUDS
AND PRECIP THREAT MAY LINGER INTO SATURDAY. NOT OVERLY EXCITED
ABOUT INSTABILITY SATURDAY PER LINGERING CLOUD COVER...THUS THINK
ANY PRECIP SATURDAY WOULD BE IN THE FORM OF SHOWERS AND LITTLE OR NO
THUNDER. FRONT IS FCST TO DISSIPATE OVER OR JUST SOUTH OF THE AREA
SATURDAY NIGHT...AMOUNT OF CLEARING DEPENDENT ON FRONTAL REMNANTS.
TEMPERATURES SATURDAY WILL BE TEMPERED BY CLOUD COVER...L-M 70S
MTS...LOWER 80S PIEDMONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 350 PM WEDNESDAY...
UPPER LEVEL TROUGH SETS UP SHOP OVER THE ERN CONUS FOR NEXT WEEK.
FLOW ALOFT REMAINS CYCLONIC WITH EMBEDDED SHORT WAVE ENERGY HELPING
TO KEEP THE FLOW AMPLIFIED. PRESENCE OF THE TROUGH SUGGESTS TEMPS
WILL RUN BLO MEDIAN. AS FOR PRECIP...A LOT WILL DEPEND ON THE
AMOUNT OF RETURN FLOW THAT CAN DEVELOP AND TIMING OF ANY SHORT WAVE
ENERGY. FOR NOW WILL FOCUS HIGHEST POPS VCNTY OF MTNS WHERE LOW
LEVEL CONVERGENCE WILL BE GREATEST...ALTHOUGH COOLER THAN NORMAL
TEMPS SUGGESTS INSTABILITY WILL BE MAINLY DIURNALLY DRIVEN.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 650 PM EDT WEDNESDAY...
FEW SHOWERS REMAIN ACROSS THE NE BUT EXPECT FURTHER DISSIPATION WITH
LOSS OF HEATING SO THINKING MAY BE ABLE TO RUN WITHOUT ANY PRECIP
MENTION TO INIT AT MOST TAF SITES OUTSIDE OF KLYH THIS EVENING.
WAVE EXITS BY MIDNIGHT WITH DECENT SUBSIDENCE SPILLING EAST
ALLOWING FOR CLEARING SKIES AND SLOWLY FALLING DEWPOINTS. HOWEVER
APPEARS ENOUGH LOW LEVEL MOISTURE MAY LINGER LONG ENOUGH TO CAUSE
FOG FORMATION IN THE VALLEYS AND IN SPOTS NEAR WHERE EARLIER RAIN
OCCURRED ESPCLY KDAN. LOW CIGS MAY ALSO BANK UP AROUND KBLF
OVERNIGHT GIVEN WEAK NW FLOW WITH MVFR/IFR FOG LIKELY. OTRW
THINKING LIFR IN FOG/STRATUS AT KLWB AND MAINLY MVFR KBCB/KDAN AND
PERHAPS KLYH.
ANY FOG AND/OR LOW CLOUDS SHOULD HAVE ERODED BY MID MORNING
THURSDAY WITH HIGH PRESSURE PROVIDING FOR VFR UNDER FEW/SCTD CU
INTO THE AFTERNOON UNDER LIGHT WINDS.
ASIDE FROM SOME LATE NIGHT FOG AT LWB/BCB ANTICIPATE THE NEXT
THREAT FOR SUB VFR TO COME WITH A FRONT FRIDAY INTO SATURDAY. THE
FRONT SLOWS AND LINGERS ACROSS THE CAROLINAS THROUGH THE WEEKEND
SUCH THAT THE THREAT OF SHOWERS MAY OCCUR ACROSS SOUTHERN
SECTIONS...WIH SOME MVFR POSSIBLE. THE FRONT WILL BE MOVING SLOWLY
EAST BY MONDAY AS HIGH PRESSURE WORKS IN FROM THE OHIO VALLEY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...JH/WP
SHORT TERM...PM
LONG TERM...PM
AVIATION...JH/RAB/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
205 AM EDT TUE AUG 14 2012
.SYNOPSIS...
HIGH PRESSURE WILL EXIT THE REGION TONIGHT AND MAKE WAY FOR AN
APPROACHING COLD FRONT. THIS FRONT WILL MOVE THROUGH THE REGION
TOMORROW EVENING. IN ITS WAKE...HIGH PRESSURE WILL RETURN TO THE
REGION WITH YET ANOTHER...AND PERHAPS STRONGER...COLD FRONT SLATED
TO CROSS THE REGION FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 115 AM EDT TUESDAY...
INCREASING LOW AND MID LEVEL MOISTURE AND WEAK FORCING ASSOCIATED
WITH WEAK SHORT WAVE TROF MOVING NORTHEAST THROUGH THE AREA
RESULTING IN EXPANDING AREA OF SHOWERS ALONG AND WEST OF THE BLUE
RIDGE. NAM MODEL DEPICTING THIS QUITE WELL...AND GENERALLY
FOLLOWED FOR THE REST OF TONIGHT...GRADUALLY MOVING AREA OF BEST
FORCING AND ASSOCIATED WIDESPREAD SHOWERS INTO AND THEN OUT OF EXTREME
NORTHERN AND WESTERN COUNTIES BY LATE TONIGHT...WITH
PRECIPITATION ENDING ACROSS THE SOUTHWESTERN COUNTIES. ISSUED
UPDATE TO HOURLY GRIDS TO REFLECT THE TIMING AND TRANSIT OF HIGHER
PRECIPITATION PROBABILITIES ACROSS THE MOUNTAINS FOR THE OVERNIGHT
PERIOD...AND TWEAKED HOURLY TEMPERATURES AND DEW POINTS A BIT TO
REFLECT CURRENT AND ANTICIPATED TRENDS FOR THE REST OF THE NIGHT.
OTHERWISE...LEFT REST OF GRID PACKAGE UNCHANGED.
AS OF 855 PM EDT MONDAY...
MOISTURE GRADUALLY RETURNING TO THE AREA TONIGHT WITH EVENING
RAOBS SHOWING ONLY A DRY LAYER REMAINING IN THE BOUNDARY LAYER AND
ANOTHER SMALL CAPPED POCKET ALOFT. INITIAL RESIDUAL BAND OF SHRA
WELL AHEAD OF THE FRONT ALONG THE MISS RIVER HAS BASICALLY FADED
CROSSING THE FAR WESTERN RIDGES BUT HAS ALLOWED FOR SOME INCREASE
IN WEAK INSTABILITY AS DEW POINTS START TO SLOWLY CREEP UP. APPEARS
WITH THIS TREND CONTINUING OVERNIGHT THAT MAY SEE ISOLATED SHRA
AFFECT THE WEST...THEN PERHAPS A BAND OR TWO LATE SPCLY NW
SECTIONS AS THE PRE-FRONTAL ZONE APPROACHES TOWARD MORNING PER THE
LATEST HRRR. THUS MADE ONLY SMALL ADJUSTS TO THE EARLIER EVENING
UPDATE WITH A SCATTERING OF 20ISH POPS PAST MIDNIGHT...THEN A BIT
HIGHER CHANCE WEST LATE. OTRW PLENTY OF CLOUDS AROUND TO MAKE
TEMPS A LITTLE MORE TRICKY AS THINGS BECOME MORE HUMID OVERNIGHT.
THINK SOME DEGREE OF CLOUDINESS WILL LINGER THEREFORE BUMPED UP LOWS A
FEW DEGREES TO THE WARM SIDE OF MOS INCLUDING THE LATEST LAV.
AS OF 612 PM EDT MONDAY...
EARLY EVENING UPDATE MAINLY TO REDUCE POPS ACROSS THE SW THIS
EVENING GIVEN MAIN AXIS OF SHRA PASSING TO THE SW...AND THEN TO
INCLUDE SOME CHANCE POPS AFTER MIDNIGHT ACROSS THE WEST PER SHRA
DEVELOPMENT BEHIND THE PRE-FRONTAL RH LOBE ATTM. THIS SUPPORTED
VIA THE LATEST HRRR WHICH BRINGS SOME OF THIS LEFTOVER CONVECTION
INTO THE WESTERN ZONES LATE IN CONJUNCTION WITH MOISTENING OF MID
LEVELS OFF LATEST FORECAST RAOBS. ALSO LOWERED TEMPS SOME OVER THE
SW WHERE HEATING WAS LESS DUE TO EARLY ARRIVAL OF THE MID DECK
CANOPY.
AS OF 315 PM EDT MONDAY...
INFLUENCE OF HIGH PRESSURE WILL CONTINUE THROUGH THIS EVENING.
PRECIPITATION WILL BE VERY LIMITED...IF EXISTS AT ALL. THE GREAT
POTENTIAL WILL BE ALONG THE CREST OF THE BLUE RIDGE SOUTHWEST OF
FLOYD INTO THE NORTHERN MOUNTAINS OF NORTH CAROLINA...AND IN AREAS
ALONG AND NEAR THE NC/VA BORDER.
OVERNIGHT...MID TO HIGH LEVEL CLOUD COVER IS EXPECTED TO OVERSPREAD
THE REGION AS DEBRIS CLOUD COVER FROM AN APPROACHING COLD FRONT
ADVECTS INTO THE REGION. THIS WILL HAVE THE RESULT OF
LIMITED...ALTHOUGH NOT COMPLETELY PREVENTING...THE DEVELOPMENT OF
PRIMARILY LATE NIGHT MOUNTAIN VALLEY FOG...ESPECIALLY OVER PARTS OF
THE GREENBRIER AND NEW RIVER VALLEYS. SOME ISOLATED TO SCATTERED
SHOWERS WILL BE POSSIBLE OVER SOUTHEAST WEST VIRGINIA BY SUNRISE IN
ASSOCIATION WITH THE APPROACHING FRONT.
ON TUESDAY...THE FRONT WILL DRAW EVEN CLOSE TO THE REGION DURING THE
DAY TUESDAY. ISENTROPIC LIFT IN ADVANCE OF THE FRONT WILL HELP TO
PROVIDE GENEROUS COVERAGE OF SHOWERS AND STORMS BY MIDDAY ACROSS ALL
BUT THE FAR EASTERN SECTIONS OF THE REGION. BY THE LATE
AFTERNOON...ALL AREAS ARE EXPECTED TO HAVE AT LEAST SCATTERED
COVERAGE OF SHOWERS AND STORMS...WITH THE GREATEST COVERAGE ACROSS
SOUTHEAST WEST VIRGINIA AND AREAS ALONG AND NEAR THE CREST OF THE
BLUE RIDGE.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 112 PM EDT MONDAY...
JUST SOME MINOR TWEAKS TO THE PREVIOUS FORECAST FOR THIS TIME
PERIOD. MODELS SHOW A DECENT SHORTWAVE SHIFTING EAST ACROSS THE ARE
TUE NIGHT INTO WED MORNING...SO EXPECT TO SEE LINGERING SHOWERS OR
STORMS IN THE EAST TUE EVENING AND SOME UPSLOPE ENHANCE SHOWERS
ACROSS THE MTNS INTO WED MORNING BEFORE SUBSIDENCE STARTS TO DRY THE
COLUMN OUT SUBSTANTIALLY. THE UPPER FLOW STAYS IN A GENERAL WRLY
DIRECTION AFTER THE FRONTAL PASSAGE AND ONLY EXPECTING MEAGER DROPS
IN THE DEW POINTS WITH TEMPS REMAINING JUST AS WARM AS TUESDAY.
A WEAK HIGH PRESSURE SYSTEM LINGERS ACROSS THE AREA INTO THURSDAY
DURING WHICH SKIES SHOULD REMAIN CLEAR-PARTLY CLOUDY.
SHOULD SEE INCREASING CLOUDS AHEAD OF NEXT TROUGH AND SFC FRONT LATE
THU NIGHT...BUT ANY PRECIP SHOULD HOLD OFF UNTIL FRIDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 112 PM EDT MONDAY...
POSITIVE PNA PATTERN WITH TROUGH IN THE EASTERN U.S./TROUGH WEST
COAST WILL BE THE UPPER AIR FLOW INTO THE EXTENDED PERIOD WITH SOME
BREAKDOWN IN THE WRN RIDGE AFTER NEXT MONDAY.
THE NEXT FRONT WILL SLIDE INTO THE AREA FRIDAY INTO SATURDAY. UPPER
PATTERN SUPPORTS SLOWER MOVEMENT OF FRONT AND COULD SEE THE FRONT
STALL JUST SOUTH AND EAST OF THE FORECAST AREA OVER THE WEEKEND. THE
ECMWF ALLUDES TO MORE CLOUDS ACROSS THE SRN CWA INTO SUNDAY WITH AN
INCREASE IN PRECIP CHANCES HEADING INTO MONDAY ACROSS SRN VA/NRN NC.
FOR NOW WILL KEEP THE AREA DRY MONDAY...PER HPC AND ENSEMBLE
LEANINGS...GIVEN THE TROUGH DOES LOOK TO DEEPEN JUST ENOUGH.
SO FOR THIS PERIOD...THINK AT LEAST A CHANCE POPS WARRANTED FRI-SAT
WITH SOME DRYING ACROSS THE REGION SAT NIGHT-SUN WITH A FEW
LINGERING SHOWERS IN THE PIEDMONT...THEN MAINLY DRY WITH INCREASING
CLOUDS AROUND SUN NIGHT INTO MONDAY ACROSS THE PIEDMONT SOUTHWEST
INTO THE NC FOOTHILLS.
TEMPS THIS PERIOD SHOULD COOL OFF AGAIN TOWARD WHAT WE HAD THIS PAST
WEEKEND WITH HIGHS IN THE 70S WEST TO LOWER 80S EAST...WHILE LOWS AT
NIGHT RANGE FROM THE LOWER 50S WEST TO LOWER 60S EAST.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 200 AM EDT TUESDAY...
AREA OF SHOWERS ALONG AND WEST OF THE BLUE RIDGE WITH AREAS OF
MVFR RESTRICTIONS...AND EVEN SOME LOCALIZED IFR CONCERNS OVER/NEAR
SOME OF THE HIGHER RIDGES WILL GRADUALLY LIFT NORTH OF BATH COUNTY
VA BEFORE DAYBREAK WITH PASSAGE OF WEAK SHORT WAVE TROF. SOME
REDEVELOPMENT OF SOME FOG WITH IFR/LIFR RESTRICTIONS IN SOME MOUNTAIN
VALLEYS THAT RECEIVED RAIN WILL BE POSSIBLE UNTIL AN HOUR OR TWO
AFTER DAYBREAK...BUT NO DIRECT IMPACT EXPECTED TO ANY TERMINAL
FORECAST POINT AT THE PRESENT TIME.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ALONG AND IN
ADVANCE OF NEXT COOL FRONT EXPECTED TO BEGIN TO IMPACT WESTERN
TERMINAL FORECAST POINTS (KLWB AND KBLF) AS A PREVAILING CONDITION
BY OR SHORTLY AFTER NOON ON TUESDAY...WITH EVENT EXPECTED TO BE MORE
SCATTERED IN NATURE DURING THE AFTERNOON FOR POINTS FURTHER EAST
(KBCB...KROA...KLYH...KDAN)...WHERE VCTS REMARKS HAVE BEEN
INSERTED. ALTHOUGH SOME LOCALIZED MVFR OR EVEN IFR FLIGHT
RESTRICTIONS ARE POSSIBLE IN SOME OF THE STRONGER STORMS...MOST
AREAS SHOULD MAINTAIN VFR WEATHER ON TUESDAY DESPITE THE THREAT OF
PRECIPITATION.
OTHERWISE...OTHER THAN LOCALIZED FLIGHT RESTRICTIONS IN
AFTERNOON/EVENING SHOWERS/STORMS...AND WITH ADDITIONAL LOCALIZED
RESTRICTIONS DUE TO PATCHY LATE NIGHT/EARLY MORNING FOG IN
MOUNTAIN VALLEYS AND LOW LYING SECTIONS THAT RECEIVE RAIN...MAINLY
VFR WEATHER IS EXPECTED TO HOLD FOR MOST TERMINAL FORECAST POINTS
THROUGH THE UPCOMING WEEK.
&&
.EQUIPMENT...
THE NOAA WEATHER RADIO FROM ROANOKE VIRGINIA IS OFF THE AIR
TONIGHT LIKELY DUE TO A PHONE PROBLEM. RETURN TO SERVICE TIME IS
UNKNOWN AS TECHNICIANS WORK ON THE PROBLEM.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...DS
NEAR TERM...DS/JH/WERT
SHORT TERM...WP
LONG TERM...WP
AVIATION...WERT
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1053 PM CDT WED AUG 15 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATE...THREAT OF SVR TSTMS HAS DIMINISHED FOR THE OVERNIGHT PERIOD.
CURRENT TSTM ACTIVITY AHEAD OF THE COLD FRONT IN MN HAS WEAKENED...
MAINLY DUE TO STRATIFORM RAIN THAT DEVELOPED AHEAD OF THE MORE VIGOROUS
CONVECTION. MUCAPE IS ONLY EXPECTED TO BE 500-800 J/KG OVER GRB CWA
AS THE TSTMS MOVE THROUGH LATER ON...SO THE SVR THREAT IS FAIRLY LOW.
SPC HAS PULLED THE SLGT RISK BACK TO THE WEST OF OUR FORECAST AREA...
WHICH SEEMS REASONABLE...SO PLAN TO REMOVE ANY MENTION OF SVR TSTMS
FROM THE HAZARDOUS WEATHER OUTLOOK. MAY MAKE SOME MINOR CHANGES TO
PCPN TIMING (PERHAPS A LITTLE FASTER) OVERNIGHT...BUT THE FCST
LOOKS TO BE IN PRETTY GOOD SHAPE OVERALL.
KIECKBUSCH
&&
.PREV DISCUSSION...ISSUED AT 650 PM CDT WED AUG 15 2012...
SHORT TERM...TONIGHT AND THURSDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE HIGH
PRESSURE MOVING TO THE EASTERN GREAT LAKES WHILE SHORTWAVE ENERGY
OVER THE LAKE WINNIPEG REGION IS PUSHING LOW PRESSURE OVER THE
NORTHERN PLAINS. SHOWERS AND THUNDERSTORMS OVER SOUTHEAST MINNESOTA
AND SOUTHWEST WISCONSIN EARLIER THIS MORNING HAVE DISSIPATED LEAVING
ONLY BANDS OF MID AND CLOUDS OVERHEAD IN A WARM ADVECTION REGIME.
ALONG THE FRONT...SHOWERS AND ISOLATED THUNDERSTORMS ARE OCCURRING
OVER NORTH DAKOTA AND NW MINNESOTA. WITH STRONG TO SEVERE STORMS
EXPECTED TO DEVELOP LATER THIS AFTERNOON ALONG THE FRONT...SEVERE
WEATHER CHANCES IS THE MAIN FORECAST CONCERN TONIGHT.
TONIGHT...SHORTWAVE TROUGH OVER LAKE WINNIPEG WILL DRIVE A STRONG
COLD FRONT ACROSS THE NORTHERN MISSISSIPPI VALLEY THIS EVENING AND
INTO CENTRAL WISCONSIN BY LATE TONIGHT. A LINE OF SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE FRONT LATER THIS
AFTERNOON...AND THEN PUSH EAST WITH THE FRONT. TIMING OF THE FRONT
MAY HAVE SLOWED A LITTLE BIT...BUT STILL EXPECT SHOWERS AND
THUNDERSTORMS TO MOVE INTO NORTH-CENTRAL AND CENTRAL WISCONSIN
SHORTLY AFTER MIDNIGHT AND INTO EASTERN WISCONSIN LATE TONIGHT.
THOUGH 0-6KM BULK SHEAR OF 40-45KTS ALONG THE FRONT IS SUFFICIENT
FOR SEVERE WEATHER...ELEVATED INSTABILITY WILL BE SLOWLY DIMINISHING
TONIGHT WITHIN THE AIRMASS AHEAD OF THE FRONT. PROGGED SOUNDINGS
INDICATE RELATIVELY SKINNY CAPE BETWEEN 800 J/KG OVER NORTH-CENTRAL
WISCONSIN TO AROUND 1000 J/KG OVER CENTRAL WISCONSIN. THERE IS A
LITTLE BIT OF A 850MB THETAE RIDGE POKING INTO CENTRAL WISCONSIN
BETWEEN 09-12Z WHICH MAY BE ABLE TO SUSTAIN STORMS BETTER...AND
CONTRIBUTE TO LOW END SEVERE THUNDERSTORM CHANCES. WITH THE SKINNY
CAPE AND DECAYING INSTABILITY...THE HAIL THREAT WILL BE MINIMAL.
BUT WINDS OF 40-45 KTS ALOFT COULD LEAD TO SMALL WIND THREAT OVER
CENTRAL WISCONSIN. ANY DESCENDING WIND WILL HAVE TO FIGHT THROUGH A
SHARP TEMPERATURE INVERSION ABOVE THE BOUNDARY LAYER SO EVEN IF
STRONG STORMS ARE PRESENT...NOT A SURE BET THEY WILL REACH THE
SURFACE. WILL MENTION THE SLIGHTLY HIGHER PROBABILITY OF SEVERE
WEATHER OVER CENTRAL WISCONSIN IN THE HWO. OTHERWISE A WARMER AND
MUGGY NIGHT WITH LOWS MAINLY IN THE 60S.
THURSDAY...THE FRONT WILL SWEEP ACROSS CENTRAL AND NORTHEAST
WISCONSIN DURING THE MORNING HOURS...KEEPING THE THREAT OF SHOWERS
AND STORMS AROUND. WILL LIKELY SEE SOME CLEARING FOR A FEW HOURS
DIRECTLY BEHIND THE FRONT AS A DRY SLOT MOVES NORTHEAST...BUT LOW
LEVEL MOISTURE QUICKLY ROTATES BACK INTO NORTH-CENTRAL AND NORTHEAST
WISCONSIN IN THE AFTERNOON THAT WILL PRODUCE SCT TO BKN CU. HIGH
TEMPS COOLING OFF INTO THE MID 60S NORTH TO MID 70S SOUTH.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY.
MODELS IN GOOD AGREEMENT FOR THE FIRST PART OF THE FORECAST...WITH
THURSDAY NIGHT AND FRIDAY LOOKING DRY OTHER THAN A FEW SHOWERS OVER
NORTHERN WISCONSIN FRIDAY AFTERNOON. AFTER THAT...MODELS ALL OVER
THE BOARD AS FAR AS PRECIP CHANCES STARTING SATURDAY MORNING AS
AN UPPER LEVEL TROUGH STALLS OVER THE EASTERN CONUS AND CREATES A
BLOCKING-LIKE PATTERN. MAIN FORECAST CHALLENGE FOR THE EXTENDED
WILL BE PRECIP CHANCES SATURDAY THROUGH TUESDAY.
...THURSDAY NIGHT THROUGH FRIDAY NIGHT...
COLD FRONT EXITS WI THURSDAY EVENING. MODELS IN AGREEMENT ON DRY
CONDITIONS STARTING THURSDAY NIGHT THROUGH FRIDAY MID- MORNING.
FRIDAY AFTERNOON EXPECTED TO BE DRY FOR MUCH OF THE CWA EXCEPT
FOR FAR NORTHERN WISCONSIN. MORE MODELS ARE TRENDING TOWARDS SHOWERY
ACTIVITY FRIDAY AFTERNOON OVER FAR NORTHERN WI. SFC HEATING
COUPLED WITH STRONG CAA IN THE MID-LEVELS COULD LEAD TO PRECIP
STARTING AR 18Z FRIDAY ACROSS ALL OF NORTHERN WI. THEREFORE
EXPANDED THE SLIGHT CHANCE POPS FURTHER WEST THAN PREVIOUS
FORECAST FOR FRIDAY AFTERNOON WHERE MID LEVEL TEMPS WILL BE
COLDEST.
AT THIS POINT...CLOUD COVER SHOULD KEEP TEMPS ABOVE LEVELS THAT
WOULD LEAD TO FROST DEVELOPMENT OVER NORTHERN WI FRIDAY NIGHT.
...SATURDAY THROUGH TUESDAY...
UPPER LEVEL TROUGH WILL STALL TO OUR EAST...PUTTING WI IN AN AREA
OF NW FLOW ALOFT. WEATHER OVER THE NEXT FEW DAYS WILL BE A RESULT OF
SHORTWAVES DIGGING THROUGH THE MEAN FLOW. EACH MODEL HANDLES THESE
SHORTWAVES DIFFERENTLY WITH VARYING IDEAS FOR TIMING AND COVERAGE
OF ANY PRECIP. THIS RESULTS IN NUMEROUS PERIODS OF SLIGHT CHANCE POPS
IN THE EXTENDED. WAS ABLE TO KEEP THINGS DRY SATURDAY AFTERNOON IN
SOUTHERN PORTIONS OF THE CWA AS GFS IS THE ONLY MODEL THAT HAS
WIDESPREAD PRECIP AND MODEL CONSENSUS KEEPS ANY SHOWERS THAT DEVELOP
OVER NORTHERN WI. SATURDAY NIGHT SHOULD BE DRY AS WELL ACROSS
ALL OF NORTHEAST WI AS WE LOSE THE DIURNAL HEATING AND PRECIP
SHOULD COME TO THE END. AFTER THAT...TOO MUCH MODEL SPREAD TO MAKE
ANY CHANGES.
TEMPERATURES SHOULD CONTINUE TO BE SLIGHTLY BELOW NORMAL THROUGH
EARLY NEXT WEEK DUE TO STRONG NW FLOW ALOFT. WARMER TEMPERATURES CAN
BE THEN BE EXPECTED TUESDAY AND WEDNESDAY AS THE FLOW TURNS SOUTH
AHEAD OF AN APPROACHING COLD FRONT.
&&
.AVIATION...A STRONG COLD FRONT WILL MOVE ACROSS THE AREA LATE
TONIGHT INTO THURSDAY MORNING. A BAND OF SHOWERS AND SCATTERED
THUNDERSTORMS WILL ACCOMPANY THE FRONT...WITH LOCALLY HEAVY RAINFALL
POSSIBLE. THE BEST CHANCE OF TSTMS IS EXPECTED BETWEEN 07Z-11Z AT
RHI/AUW/CWA AND 10Z-14Z AT ATW/GRB. MARGINAL LLWS IS EXPECTED AT
GRB/ATW UNTIL THE FRONT MOVES THROUGH (AROUND 14Z). ALTHOUGH THE
SHOWERS WILL TAPER OFF THURSDAY MORNING...MVFR CIGS ARE EXPECTED
TO LINGER AT THE TAF SITES UNTIL ABOUT MIDDAY. GUSTY NW WINDS AND
PARTIAL CLEARING CAN BE EXPECTED DURING THE AFTERNOON...WITH
PARTLY CLOUDY SKIES AND DIMINISHING WINDS BY EVENING.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
848 PM CDT WED AUG 15 2012
.UPDATE...THREAT OF SVR TSTMS HAS DIMINISHED FOR THE OVERNIGHT PERIOD.
CURRENT TSTM ACTIVITY AHEAD OF THE COLD FRONT IN MN HAS WEAKENED...
MAINLY DUE TO STRATIFORM RAIN THAT DEVELOPED AHEAD OF THE MORE VIGOROUS
CONVECTION. MUCAPE IS ONLY EXPECTED TO BE 500-800 J/KG OVER GRB CWA
AS THE TSTMS MOVE THROUGH LATER ON...SO THE SVR THREAT IS FAIRLY LOW.
SPC HAS PULLED THE SLGT RISK BACK TO THE WEST OF OUR FORECAST AREA...
WHICH SEEMS REASONABLE...SO PLAN TO REMOVE ANY MENTION OF SVR TSTMS
FROM THE HAZARDOUS WEATHER OUTLOOK. MAY MAKE SOME MINOR CHANGES TO
PCPN TIMING (PERHAPS A LITTLE FASTER) OVERNIGHT...BUT THE FCST
LOOKS TO BE IN PRETTY GOOD SHAPE OVERALL.
KIECKBUSCH
&&
.PREV DISCUSSION...ISSUED AT 650 PM CDT WED AUG 15 2012...
SHORT TERM...TONIGHT AND THURSDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE HIGH
PRESSURE MOVING TO THE EASTERN GREAT LAKES WHILE SHORTWAVE ENERGY
OVER THE LAKE WINNIPEG REGION IS PUSHING LOW PRESSURE OVER THE
NORTHERN PLAINS. SHOWERS AND THUNDERSTORMS OVER SOUTHEAST MINNESOTA
AND SOUTHWEST WISCONSIN EARLIER THIS MORNING HAVE DISSIPATED LEAVING
ONLY BANDS OF MID AND CLOUDS OVERHEAD IN A WARM ADVECTION REGIME.
ALONG THE FRONT...SHOWERS AND ISOLATED THUNDERSTORMS ARE OCCURRING
OVER NORTH DAKOTA AND NW MINNESOTA. WITH STRONG TO SEVERE STORMS
EXPECTED TO DEVELOP LATER THIS AFTERNOON ALONG THE FRONT...SEVERE
WEATHER CHANCES IS THE MAIN FORECAST CONCERN TONIGHT.
TONIGHT...SHORTWAVE TROUGH OVER LAKE WINNIPEG WILL DRIVE A STRONG
COLD FRONT ACROSS THE NORTHERN MISSISSIPPI VALLEY THIS EVENING AND
INTO CENTRAL WISCONSIN BY LATE TONIGHT. A LINE OF SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE FRONT LATER THIS
AFTERNOON...AND THEN PUSH EAST WITH THE FRONT. TIMING OF THE FRONT
MAY HAVE SLOWED A LITTLE BIT...BUT STILL EXPECT SHOWERS AND
THUNDERSTORMS TO MOVE INTO NORTH-CENTRAL AND CENTRAL WISCONSIN
SHORTLY AFTER MIDNIGHT AND INTO EASTERN WISCONSIN LATE TONIGHT.
THOUGH 0-6KM BULK SHEAR OF 40-45KTS ALONG THE FRONT IS SUFFICIENT
FOR SEVERE WEATHER...ELEVATED INSTABILITY WILL BE SLOWLY DIMINISHING
TONIGHT WITHIN THE AIRMASS AHEAD OF THE FRONT. PROGGED SOUNDINGS
INDICATE RELATIVELY SKINNY CAPE BETWEEN 800 J/KG OVER NORTH-CENTRAL
WISCONSIN TO AROUND 1000 J/KG OVER CENTRAL WISCONSIN. THERE IS A
LITTLE BIT OF A 850MB THETAE RIDGE POKING INTO CENTRAL WISCONSIN
BETWEEN 09-12Z WHICH MAY BE ABLE TO SUSTAIN STORMS BETTER...AND
CONTRIBUTE TO LOW END SEVERE THUNDERSTORM CHANCES. WITH THE SKINNY
CAPE AND DECAYING INSTABILITY...THE HAIL THREAT WILL BE MINIMAL.
BUT WINDS OF 40-45 KTS ALOFT COULD LEAD TO SMALL WIND THREAT OVER
CENTRAL WISCONSIN. ANY DESCENDING WIND WILL HAVE TO FIGHT THROUGH A
SHARP TEMPERATURE INVERSION ABOVE THE BOUNDARY LAYER SO EVEN IF
STRONG STORMS ARE PRESENT...NOT A SURE BET THEY WILL REACH THE
SURFACE. WILL MENTION THE SLIGHTLY HIGHER PROBABILITY OF SEVERE
WEATHER OVER CENTRAL WISCONSIN IN THE HWO. OTHERWISE A WARMER AND
MUGGY NIGHT WITH LOWS MAINLY IN THE 60S.
THURSDAY...THE FRONT WILL SWEEP ACROSS CENTRAL AND NORTHEAST
WISCONSIN DURING THE MORNING HOURS...KEEPING THE THREAT OF SHOWERS
AND STORMS AROUND. WILL LIKELY SEE SOME CLEARING FOR A FEW HOURS
DIRECTLY BEHIND THE FRONT AS A DRY SLOT MOVES NORTHEAST...BUT LOW
LEVEL MOISTURE QUICKLY ROTATES BACK INTO NORTH-CENTRAL AND NORTHEAST
WISCONSIN IN THE AFTERNOON THAT WILL PRODUCE SCT TO BKN CU. HIGH
TEMPS COOLING OFF INTO THE MID 60S NORTH TO MID 70S SOUTH.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY.
MODELS IN GOOD AGREEMENT FOR THE FIRST PART OF THE FORECAST...WITH
THURSDAY NIGHT AND FRIDAY LOOKING DRY OTHER THAN A FEW SHOWERS OVER
NORTHERN WISCONSIN FRIDAY AFTERNOON. AFTER THAT...MODELS ALL OVER
THE BOARD AS FAR AS PRECIP CHANCES STARTING SATURDAY MORNING AS
AN UPPER LEVEL TROUGH STALLS OVER THE EASTERN CONUS AND CREATES A
BLOCKING-LIKE PATTERN. MAIN FORECAST CHALLENGE FOR THE EXTENDED
WILL BE PRECIP CHANCES SATURDAY THROUGH TUESDAY.
...THURSDAY NIGHT THROUGH FRIDAY NIGHT...
COLD FRONT EXITS WI THURSDAY EVENING. MODELS IN AGREEMENT ON DRY
CONDITIONS STARTING THURSDAY NIGHT THROUGH FRIDAY MID- MORNING.
FRIDAY AFTERNOON EXPECTED TO BE DRY FOR MUCH OF THE CWA EXCEPT
FOR FAR NORTHERN WISCONSIN. MORE MODELS ARE TRENDING TOWARDS SHOWERY
ACTIVITY FRIDAY AFTERNOON OVER FAR NORTHERN WI. SFC HEATING
COUPLED WITH STRONG CAA IN THE MID-LEVELS COULD LEAD TO PRECIP
STARTING AR 18Z FRIDAY ACROSS ALL OF NORTHERN WI. THEREFORE
EXPANDED THE SLIGHT CHANCE POPS FURTHER WEST THAN PREVIOUS
FORECAST FOR FRIDAY AFTERNOON WHERE MID LEVEL TEMPS WILL BE
COLDEST.
AT THIS POINT...CLOUD COVER SHOULD KEEP TEMPS ABOVE LEVELS THAT
WOULD LEAD TO FROST DEVELOPMENT OVER NORTHERN WI FRIDAY NIGHT.
...SATURDAY THROUGH TUESDAY...
UPPER LEVEL TROUGH WILL STALL TO OUR EAST...PUTTING WI IN AN AREA
OF NW FLOW ALOFT. WEATHER OVER THE NEXT FEW DAYS WILL BE A RESULT OF
SHORTWAVES DIGGING THROUGH THE MEAN FLOW. EACH MODEL HANDLES THESE
SHORTWAVES DIFFERENTLY WITH VARYING IDEAS FOR TIMING AND COVERAGE
OF ANY PRECIP. THIS RESULTS IN NUMEROUS PERIODS OF SLIGHT CHANCE POPS
IN THE EXTENDED. WAS ABLE TO KEEP THINGS DRY SATURDAY AFTERNOON IN
SOUTHERN PORTIONS OF THE CWA AS GFS IS THE ONLY MODEL THAT HAS
WIDESPREAD PRECIP AND MODEL CONSENSUS KEEPS ANY SHOWERS THAT DEVELOP
OVER NORTHERN WI. SATURDAY NIGHT SHOULD BE DRY AS WELL ACROSS
ALL OF NORTHEAST WI AS WE LOSE THE DIURNAL HEATING AND PRECIP
SHOULD COME TO THE END. AFTER THAT...TOO MUCH MODEL SPREAD TO MAKE
ANY CHANGES.
TEMPERATURES SHOULD CONTINUE TO BE SLIGHTLY BELOW NORMAL THROUGH
EARLY NEXT WEEK DUE TO STRONG NW FLOW ALOFT. WARMER TEMPERATURES CAN
BE THEN BE EXPECTED TUESDAY AND WEDNESDAY AS THE FLOW TURNS SOUTH
AHEAD OF AN APPROACHING COLD FRONT.
&&
.AVIATION...A WARM FRONT LIFTING NORTHEAST ACROSS THE STATE WILL
BRING ISOLATED SHOWERS TO THE AREA THIS EVENING. COVERAGE WILL BE
TOO SPOTTY TO INCLUDE IN THE TAFS. A STRONG COLD FRONT WILL MOVE
ACROSS THE AREA LATE TONIGHT INTO THURSDAY MORNING. A BAND OF
SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE FRONT AND SOME STORMS
COULD PRODUCE GUSTY WINDS UP TO 40 KTS AND SMALL HAIL. THE BEST
CHANCE OF TSTMS IS EXPECTED BETWEEN 08Z-11Z AT RHI/AUW/CWA AND
11Z-14Z AT ATW/GRB. LLWS IS POSSIBLE AT GRB/ATW STARTING AROUND
MIDNIGHT AND CONTINUING UNTIL THE FRONT MOVES THROUGH (AROUND
14Z). ALTHOUGH THE SHOWERS WILL TAPER OFF LATE TONIGHT INTO
THURSDAY MORNING...MVFR CIGS ARE EXPECTED TO LINGER AT THE TAF
SITES THROUGH MOST OF THURSDAY MORNING. GUSTY NW WINDS AND
PARTIAL CLEARING CAN BE EXPECTED DURING THE AFTERNOON.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
650 PM CDT WED AUG 15 2012
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND THURSDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE HIGH
PRESSURE MOVING TO THE EASTERN GREAT LAKES WHILE SHORTWAVE ENERGY
OVER THE LAKE WINNIPEG REGION IS PUSHING LOW PRESSURE OVER THE
NORTHERN PLAINS. SHOWERS AND THUNDERSTORMS OVER SOUTHEAST MINNESOTA
AND SOUTHWEST WISCONSIN EARLIER THIS MORNING HAVE DISSIPATED LEAVING
ONLY BANDS OF MID AND CLOUDS OVERHEAD IN A WARM ADVECTION REGIME.
ALONG THE FRONT...SHOWERS AND ISOLATED THUNDERSTORMS ARE OCCURRING
OVER NORTH DAKOTA AND NW MINNESOTA. WITH STRONG TO SEVERE STORMS
EXPECTED TO DEVELOP LATER THIS AFTERNOON ALONG THE FRONT...SEVERE
WEATHER CHANCES IS THE MAIN FORECAST CONCERN TONIGHT.
TONIGHT...SHORTWAVE TROUGH OVER LAKE WINNIPEG WILL DRIVE A STRONG
COLD FRONT ACROSS THE NORTHERN MISSISSIPPI VALLEY THIS EVENING AND
INTO CENTRAL WISCONSIN BY LATE TONIGHT. A LINE OF SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE FRONT LATER THIS
AFTERNOON...AND THEN PUSH EAST WITH THE FRONT. TIMING OF THE FRONT
MAY HAVE SLOWED A LITTLE BIT...BUT STILL EXPECT SHOWERS AND
THUNDERSTORMS TO MOVE INTO NORTH-CENTRAL AND CENTRAL WISCONSIN
SHORTLY AFTER MIDNIGHT AND INTO EASTERN WISCONSIN LATE TONIGHT.
THOUGH 0-6KM BULK SHEAR OF 40-45KTS ALONG THE FRONT IS SUFFICIENT
FOR SEVERE WEATHER...ELEVATED INSTABILITY WILL BE SLOWLY DIMINISHING
TONIGHT WITHIN THE AIRMASS AHEAD OF THE FRONT. PROGGED SOUNDINGS
INDICATE RELATIVELY SKINNY CAPE BETWEEN 800 J/KG OVER NORTH-CENTRAL
WISCONSIN TO AROUND 1000 J/KG OVER CENTRAL WISCONSIN. THERE IS A
LITTLE BIT OF A 850MB THETAE RIDGE POKING INTO CENTRAL WISCONSIN
BETWEEN 09-12Z WHICH MAY BE ABLE TO SUSTAIN STORMS BETTER...AND
CONTRIBUTE TO LOW END SEVERE THUNDERSTORM CHANCES. WITH THE SKINNY
CAPE AND DECAYING INSTABILITY...THE HAIL THREAT WILL BE MINIMAL.
BUT WINDS OF 40-45 KTS ALOFT COULD LEAD TO SMALL WIND THREAT OVER
CENTRAL WISCONSIN. ANY DESCENDING WIND WILL HAVE TO FIGHT THROUGH A
SHARP TEMPERATURE INVERSION ABOVE THE BOUNDARY LAYER SO EVEN IF
STRONG STORMS ARE PRESENT...NOT A SURE BET THEY WILL REACH THE
SURFACE. WILL MENTION THE SLIGHTLY HIGHER PROBABILITY OF SEVERE
WEATHER OVER CENTRAL WISCONSIN IN THE HWO. OTHERWISE A WARMER AND
MUGGY NIGHT WITH LOWS MAINLY IN THE 60S.
THURSDAY...THE FRONT WILL SWEEP ACROSS CENTRAL AND NORTHEAST
WISCONSIN DURING THE MORNING HOURS...KEEPING THE THREAT OF SHOWERS
AND STORMS AROUND. WILL LIKELY SEE SOME CLEARING FOR A FEW HOURS
DIRECTLY BEHIND THE FRONT AS A DRY SLOT MOVES NORTHEAST...BUT LOW
LEVEL MOISTURE QUICKLY ROTATES BACK INTO NORTH-CENTRAL AND NORTHEAST
WISCONSIN IN THE AFTERNOON THAT WILL PRODUCE SCT TO BKN CU. HIGH
TEMPS COOLING OFF INTO THE MID 60S NORTH TO MID 70S SOUTH.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY.
MODELS IN GOOD AGREEMENT FOR THE FIRST PART OF THE FORECAST...WITH
THURSDAY NIGHT AND FRIDAY LOOKING DRY OTHER THAN A FEW SHOWERS OVER
NORTHERN WISCONSIN FRIDAY AFTERNOON. AFTER THAT...MODELS ALL OVER
THE BOARD AS FAR AS PRECIP CHANCES STARTING SATURDAY MORNING AS
AN UPPER LEVEL TROUGH STALLS OVER THE EASTERN CONUS AND CREATES A
BLOCKING-LIKE PATTERN. MAIN FORECAST CHALLENGE FOR THE EXTENDED
WILL BE PRECIP CHANCES SATURDAY THROUGH TUESDAY.
...THURSDAY NIGHT THROUGH FRIDAY NIGHT...
COLD FRONT EXITS WI THURSDAY EVENING. MODELS IN AGREEMENT ON DRY
CONDITIONS STARTING THURSDAY NIGHT THROUGH FRIDAY MID- MORNING.
FRIDAY AFTERNOON EXPECTED TO BE DRY FOR MUCH OF THE CWA EXCEPT
FOR FAR NORTHERN WISCONSIN. MORE MODELS ARE TRENDING TOWARDS SHOWERY
ACTIVITY FRIDAY AFTERNOON OVER FAR NORTHERN WI. SFC HEATING
COUPLED WITH STRONG CAA IN THE MID-LEVELS COULD LEAD TO PRECIP
STARTING AR 18Z FRIDAY ACROSS ALL OF NORTHERN WI. THEREFORE
EXPANDED THE SLIGHT CHANCE POPS FURTHER WEST THAN PREVIOUS
FORECAST FOR FRIDAY AFTERNOON WHERE MID LEVEL TEMPS WILL BE
COLDEST.
AT THIS POINT...CLOUD COVER SHOULD KEEP TEMPS ABOVE LEVELS THAT
WOULD LEAD TO FROST DEVELOPMENT OVER NORTHERN WI FRIDAY NIGHT.
...SATURDAY THROUGH TUESDAY...
UPPER LEVEL TROUGH WILL STALL TO OUR EAST...PUTTING WI IN AN AREA
OF NW FLOW ALOFT. WEATHER OVER THE NEXT FEW DAYS WILL BE A RESULT OF
SHORTWAVES DIGGING THROUGH THE MEAN FLOW. EACH MODEL HANDLES THESE
SHORTWAVES DIFFERENTLY WITH VARYING IDEAS FOR TIMING AND COVERAGE
OF ANY PRECIP. THIS RESULTS IN NUMEROUS PERIODS OF SLIGHT CHANCE POPS
IN THE EXTENDED. WAS ABLE TO KEEP THINGS DRY SATURDAY AFTERNOON IN
SOUTHERN PORTIONS OF THE CWA AS GFS IS THE ONLY MODEL THAT HAS
WIDESPREAD PRECIP AND MODEL CONSENSUS KEEPS ANY SHOWERS THAT DEVELOP
OVER NORTHERN WI. SATURDAY NIGHT SHOULD BE DRY AS WELL ACROSS
ALL OF NORTHEAST WI AS WE LOSE THE DIURNAL HEATING AND PRECIP
SHOULD COME TO THE END. AFTER THAT...TOO MUCH MODEL SPREAD TO MAKE
ANY CHANGES.
TEMPERATURES SHOULD CONTINUE TO BE SLIGHTLY BELOW NORMAL THROUGH
EARLY NEXT WEEK DUE TO STRONG NW FLOW ALOFT. WARMER TEMPERATURES CAN
BE THEN BE EXPECTED TUESDAY AND WEDNESDAY AS THE FLOW TURNS SOUTH
AHEAD OF AN APPROACHING COLD FRONT.
&&
.AVIATION...A WARM FRONT LIFTING NORTHEAST ACROSS THE STATE WILL
BRING ISOLATED SHOWERS TO THE AREA THIS EVENING. COVERAGE WILL BE
TOO SPOTTY TO INCLUDE IN THE TAFS. A STRONG COLD FRONT WILL MOVE
ACROSS THE AREA LATE TONIGHT INTO THURSDAY MORNING. A BAND OF
SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE FRONT AND SOME STORMS
COULD PRODUCE GUSTY WINDS UP TO 40 KTS AND SMALL HAIL. THE BEST
CHANCE OF TSTMS IS EXPECTED BETWEEN 08Z-11Z AT RHI/AUW/CWA AND
11Z-14Z AT ATW/GRB. LLWS IS POSSIBLE AT GRB/ATW STARTING AROUND
MIDNIGHT AND CONTINUING UNTIL THE FRONT MOVES THROUGH (AROUND
14Z). ALTHOUGH THE SHOWERS WILL TAPER OFF LATE TONIGHT INTO
THURSDAY MORNING...MVFR CIGS ARE EXPECTED TO LINGER AT THE TAF
SITES THROUGH MOST OF THURSDAY MORNING. GUSTY NW WINDS AND
PARTIAL CLEARING CAN BE EXPECTED DURING THE AFTERNOON.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
300 PM CDT TUE AUG 14 2012
.SHORT TERM...TONIGHT THROUGH FRIDAY
300 PM CDT TUE AUG 14 2012
SHOWER/THUNDERSTORM CHANCES THROUGH THURSDAY AND TEMPERATURES ARE
THE MAIN CONCERN THROUGH THE SHORT TERM PERIOD.
LATEST WATER VAPOR IMAGERY ALONG WITH RAP 500MB HEIGHT ANALYSIS
SHOWS A COUPLE MID-LEVEL SHORTWAVE TROUGHS DROPPING THROUGH
NORTHWEST FLOW ALOFT ACROSS IA AND MN INTO NEBRASKA. MORE ENERGETIC
WAVE POISED TO AFFECT THE AREA IN THE NEXT 12-24 HOURS WAS MAKING
ITS WAY SOUTHEAST ACROSS THE ALBERTA ROCKIES. RADAR MOSAIC
SHOWING A BAND OF SCATTERED ELEVATED SHRA ACTIVITY ACROSS SOUTHEAST
ND INTO SOUTHWEST MN IN DECENT ISENTROPIC LIFT/MOISTURE TRANSPORT
AHEAD OF THE MN/NEB WAVE AND SURFACE WARM FRONT. MEANWHILE...
VISIBLE SATELLITE SHOWING AN EXPANSIVE FIELD OF CUMULUS ACROSS THE
LOCAL FORECAST AREA WITH INFLUENCE OF LINGERING COLD AIR ALOFT/STEEP
LAPSE RATES. TEMPERATURES ACROSS THE AREA AT 2 PM WERE IN THE 70S
TO LOWER 80S.
14.12Z NCEP MODELS/14.09Z SREF IN GOOD AGREEMENT WITH SYNOPTIC SETUP
THROUGH THE SHORT TERM PERIOD.
WILL BE WATCHING THE MN-NEB MID-LEVEL TROUGH AND SURFACE WARM FRONT
APPROACH THE AREA THIS EVENING/OVERNIGHT. NAM INDICATING
INCREASING/IMPRESSIVE 305K ISENTROPIC LIFT ALONG WITH STRONG
850-700MB FRONTOGENESIS/MOISTURE TRANSPORT AHEAD OF THE WARM FRONT
FOR ACCAS DEVELOPMENT ALONG WITH LIKELIHOOD OF SHRA/ISOLD T
ACTIVITY. BASED ON THIS SIGNAL...BUMPED POPS INTO 50-60 PERCENT
RANGE...WITH AREAS FROM LAKE CITY MN THROUGH LA CROSSE AND VIROQUA
LIKELY BEING THE AXIS OF HIGHEST PROBABILITIES. RIGHT NOW...IT
APPEARS THUNDER WILL BE ISOLATED IN NATURE WITH ELEVATED
CAPE/850-700MB ONLY APPROACHING 500J/KG.
GOOD CHANCE OF LINGERING SHRA/ISOLD THUNDER FOR AREAS ALONG/NORTH OF
I-94 WEDNESDAY MORNING AS THE WARM FRONT PUSHES THROUGH SOUTHEAST MN
INTO SOUTHWEST WI. APPEARS THE WARM FRONT WILL PUSH NORTHEAST OF THE
AREA BY AFTERNOON WITH THE AREA IN GENERAL WARM AIR ADVECTION AHEAD
OF A FAIRLY STRONG COLD FRONT PUSHING EAST ACROSS MN. KEPT SLIGHT
SHRA/TS CHANCES IN FOR AREAS ALONG/NORTHEAST OF I-94 THROUGH THE
AFTERNOON TO ACCOUNT FOR EXITING WARM FRONT. OTHERWISE...LOOK FOR
TEMPERATURES TO TOP OFF IN THE MIDDLE/UPPER 80S SOUTHWEST OF I-94
AND IN THE UPPER 70S/AROUND 80 NORTHEAST OF I-94 WITH MORE CLOUD
COVER THERE.
WILL HAVE TO WATCH FOR SEVERE POTENTIAL GOING INTO WEDNESDAY
EVENING. ANTICIPATING A FAIRLY SOLID LINE OF THUNDERSTORMS FIRING
ALONG THE COLD FRONT ACROSS MN INTO NORTHWEST IA BY LATER WEDNESDAY
AFTERNOON AS 0-3KM MUCAPE PUSH INTO THE 2500-5000J/KG RANGE ALONG
WITH AMPLE BULK SHEAR. THIS FRONT/LINE OF THUNDERSTORMS WILL BE
MOVING INTO THE AREA WEDNESDAY EVENING/OVERNIGHT. LINE SHOULD BE IN
A WEAKENING STATE OVERNIGHT AS CAPE WANES. HOWEVER..CANNOT RULE OUT
SEVERE HAIL/WIND THREAT FOR WESTERN PORTIONS OF THE FORECAST
AREA...MAINLY WEST OF A LINE FROM LAKE CITY AND ROCHESTER MN...TO
CHARLES CITY IA.
LOOK FOR THE COLD FRONT TO PUSH SOUTHEAST OF THE AREA BY THURSDAY
MORNING...TAKING THE BULK OF THE SHOWER/THUNDERSTORMS WITH IT.
HOWEVER...IT APPEARS A SECONDARY TROUGH/SURFACE REFLECTION OF
MID-LEVEL TROUGH LAGS THE COLD FRONT FOR SHRA/TS CHANCES LINGERING
THROUGH THE MORNING HOURS ACROSS THE ENTIRE AREA AND SOUTHEAST OF A
MAUSTON TO PRAIRIE DU CHIEN LINE DURING THE AFTERNOON.
MEANWHILE...VERY COLD AIR ALOFT/STEEPENING LAPSE RATES DURING THE
AFTERNOON ALSO EXPECTED TO KICK OFF QUITE A BIT OF CUMULUS ACROSS
THE REMAINDER OF THE AREA. HIGHS ON THURSDAY ONLY EXPECTED TO TOP
OFF IN THE UPPER 60S TO MIDDLE 70S.
THURSDAY NIGHT THROUGH FRIDAY WILL BE COOLER THAN NORMAL WITH DEEP
MID-LEVEL TROUGH DIGGING INTO THE CENTRAL CONUS/GREAT LAKES REGIONS.
CUMULUS FIELD SHOULD BE QUITE IMPRESSIVE FRIDAY AFTERNOON AS WELL
WITH THE COLD AIR ALOFT/STEEP LAPSE RATES. LOOK FOR LOWS IN THE
UPPER 40S/LOWER 50S THURSDAY NIGHT AND HIGHS ON FRIDAY IN THE UPPER
60S/LOWER 70S.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
300 PM CDT TUE AUG 14 2012
LATEST GFS/ECMWF SHOWING LONG WAVE TROUGH CARVED OUT ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY/GREAT LAKES REGION. STEEP LAPSE RATES
WILL EXIST THROUGH THE PERIOD WITH MODELS SHOWING A SHORTWAVE TROUGH
DROPPING IN ACROSS THE AREA SATURDAY FOR A TRIGGER FOR ISOLATED SHRA
DEVELOPMENT. LOOKS LIKE ANOTHER INNOCUOUS EMBEDDED SHORTWAVE TROUGH
WITHIN THE LONG WAVE/COLD TROUGH MAY BE ENOUGH ON SUNDAY FOR ANOTHER
ROUND OF ISOLATED SHOWERS. TEMPERATURES WILL REMAIN COOLER THAN
NORMAL UNDER THE TROUGH WITH HIGHS SATURDAY/SUNDAY TOPPING OFF IN
THE UPPER 60S/LOWER 70S. LOOK FOR THE TROUGH AXIS TO MOVE EAST OF
THE AREA ON MONDAY WITH SOME RIDGING ALOFT FOR DRIER AND SLIGHT
WARMER CONDITIONS. HIGHS ON MONDAY EXPECTED TO BE IN THE LOW/MID 70S.
THE GFS/EC DIVERGE ON THEIR SOLUTION ON TUESDAY. THE GFS BRINGS A
WING OF WARM AIR ADVECTION -SHRA/TS ACTIVITY INTO THE AREA WHEREAS
THE ECMWF MAINTAINS DRY SCENARIO IN WARM AIR ADVECTION. WENT WITH
MODEL CONSENSUS WHICH YIELDS A SLIGHT CHANCE OF SHOWER AND
THUNDERSTORMS. OTHERWISE...HIGHS ON TUESDAY EXPECTED TO WARM INTO
THE UPPER 70S/LOWER 80S.
&&
.AVIATION...THROUGH 18Z WEDNESDAY
1239 PM CDT TUE AUG 14 2012
WEAK 700 TO 600 FRONTOGENESIS WILL DEVELOP ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA LATE THIS AFTERNOON. THIS MAY RESULT
IN THE DEVELOPMENT OF ISOLATED SHOWERS AND THUNDERSTORMS. THE
AREAL COVERAGE AND CONFIDENCE WAS NOT HIGH ENOUGH TO ADD ANY
PRECIPITATION INTO THE KRST TAF.
FOR TONIGHT AND EARLY WEDNESDAY...STRONG FRONTOGENESIS DEVELOPS
ACROSS THE AREA. THIS IS IN RESPONSE TO WAVE MOVING OUT OF THE
DAKOTAS. IN ADDITION...THERE THERE WILL MODERATE TO STRONG 925 AND
850 MB MOISTURE TRANSPORT. AS A RESULT WENT WITH VCSH FROM 15.02Z
TO 15.13Z AT KRST...AND FROM 15.04Z TO 15.13Z AT KLSE.
CEILINGS WILL REMAIN BETWEEN 5 AND 10K THROUGH THIS PERIOD AND
VISIBILITIES WILL BE MAINLY ABOVE 6 MILES. HOWEVER COULD NOT RULE
OUT THE VISIBILITIES DROPPING DOWN BRIEFLY TO A MILE IN THE
HEAVIER SHOWERS AND ISOLATED THUNDERSTORMS. CONFIDENCE WAS WAY TOO
LOW TO ADD THIS TO EITHER TAF SITE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
300 PM CDT TUE AUG 14 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...JSB
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
251 PM CDT TUE AUG 14 2012
.SHORT TERM...TONIGHT AND WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW WEAK HIGH
PRESSURE CENTERED OVER THE MISSISSIPPI VALLEY EARLY THIS AFTERNOON.
DIURNAL CU HAS BEEN FEISTY IN SPOTS WITH A FEW SHOWERS POPPING UP
OVER CENTRAL AND SOUTHERN WISCONSIN AND ALSO OVER THE UPPER
PENINSULA. MEANWHILE UPSTREAM...A BAND OF MID AND HIGH LEVEL CLOUDS
ARE PUSHING SOUTHEAST OVER MINNESOTA WHERE AREA RADARS ARE PICKING
UP ON WEAK RETURNS. EVEN FARTHER WEST..THE NEXT STORM SYSTEM IS
GATHERING STRENGTH NORTH OF THE MONTANA BORDER. AS RETURN FLOW
DEVELOPS ALOFT AND MID LEVEL CLOUDS ARRIVE...CLOUD COVER AND SMALL
PRECIP CHANCES ARE THE MAIN FORECAST CONCERNS OVER THE NEXT 24 HOURS.
TONIGHT...ANY SPOTTY SHOWERS THIS AFTERNOON WILL DIMINISH EARLY WITH
LOSS OF HEATING. OTHERWISE...NORTHWEST FLOW ALOFT WILL PREVAIL
ACROSS THE STATE AND BRING IN A BATCH OF MID AND HIGH CLOUDS FROM
MINNESOTA. WEAK LIFT ALONG THE 700MB THETAE GRADIENT MAY EVEN TRY
TO BRING A FEW SHOWERS TO CENTRAL WISCONSIN AFTER MIDNIGHT. WILL BE
FALLING OUT OF A MID DECK AND NOT CONFIDENT THAT ANY SHOWERS WILL
MEASURE...BUT WILL ADD A SLIGHT CHANCE TO THE FORECAST. WITH THE
CLOUD COVER...NOT EXPECTING A REPEAT OF THE FOG OVER N-C WISCONSIN
TONIGHT. A PARTLY TO MOSTLY CLOUDY NIGHT WITH LOWS RANGING THROUGH
THE 50S.
WEDNESDAY...AS A STRONG COLD FRONT MOVES INTO MINNESOTA...SW TO WEST
WINDS WILL BE WARM AND MOIST ADVECTING BETWEEN 850-700MB ACROSS THE
AREA OVER THE COURSE OF THE DAY. PROGGED SOUNDINGS DRY OUT BELOW
800MB...BUT PRECIP OVER THE EASTERN DAKOTAS AND MINNESOTA IS STILL
REACHING THE GROUND SO WILL EXPAND SLIGHT CHANCE OF SHOWERS TO THE
WESTERN FOX VALLEY. MID-LEVEL LAPSE RATE GRADIENT WILL ALSO NUDGE
INTO CENTRAL WISCONSIN INTO THE AFTERNOON...AND WILL KEEP A MENTION
OF ISOLATED THUNDER THERE. WITH THE BKN MID CLOUD DECK AND POTENTIAL
FOR LIGHT SHOWERS...TEMPERATURES WILL BE A STRUGGLE...MORE OR LESS
WENT WITH A BLEND OF THE PREVIOUS FORECAST WITH THE BCALLBLEND.
THIS WOULD PUT HIGHS IN THE UPPER 70S NORTH TO MID 80S SOUTH.
.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY. THE MODELS ARE
NOW IN GOOD AGREEMENT WITH MOVING THE UPPER TROUGH FROM THE
CANADIAN ROCKIES TO GREAT LAKES OVER THE NEXT SEVERAL DAYS WITH A
REINFORCING UPPER TROUGH SATURDAY. THIS SHOULD KEEP CYCLONIC UPPER
FLOW ACROSS THE REGION THROUGH THE PERIOD WITH COOLER THAN NORMAL
TEMPERATURES AND DRY WEATHER MOST OF THE TIME.
SHOWERS AND THUNDERSTORMS WILL ARRIVE IN THE WESTERN PORTION OF
THE FORECAST AREA LATE WEDNESDAY NIGHT IN AN AREA OF UPPER
DIFFLUENCE AND LOW LEVEL WARM ADVECTION AND MOISTURE CONVERGENCE.
THE ARRIVAL OF THE FRONT DURING THE NIGHT TIME HOURS WILL MINIMIZE
THE SEVERAL THREAT. THE ACTIVITY WILL MOVE ACROSS EASTERN
WISCONSIN THURSDAY MORNING AND SHOULD EXIT THE AREA DURING THE
AFTERNOON. BREEZY AND COOLER THURSDAY NIGHT AND FRIDAY AS UPPER
HEIGHTS FALL AND BIG COOL SURFACE HIGH BUILDS IN FROM THE NORTHERN
PLAINS. CLEAR SKIES AND LIGHT WINDS SHOULD ALLOW TEMPERATURES TO
FALL INTO THE 30S IN THE USUAL COOL PLACES FRIDAY NIGHT WITH
POSSIBLE FROST.
AN UPPER TROUGH AND ASSOCIATED SURFACE FRONT WILL BRING A
REINFORCING PUSH OF COOL AIR SATURDAY AFTERNOON AND MAY BE
ACCOMPANIED BY A FEW SHOWERS. SCATTERED SHOWERS POSSIBLE ALSO
SUNDAY AFTERNOON IN CYCLONIC COLD UPPER FLOW.
&&
.AVIATION...FOR 12Z TAF ISSUANCE. SOME LIFR CIGS/FG WL LINGTER TO
ARND DAYBREAK TDA...THEN VFR CONDITIONS EXPECTED FOR THE REST OF
THE PERIOD.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/RDM
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
127 AM EDT THU AUG 16 2012
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM AND WEAK LOW PRESSURE ACROSS THE AREA
LATE THIS AFTERNOON WILL MOVE TO THE EAST OVERNIGHT. THIS WILL ALLOW
HIGH PRESSURE FROM THE OHIO VALLEY TO BUILD ACROSS THE REGION. THIS
HIGH WILL REMAIN THROUGH FRIDAY EVENING...BEFORE A COLD FRONT
CROSSES THE AREA. THIS FRONT WILL SLOW DOWN AS IT MOVES OFF THE
COAST SATURDAY. MORE HIGH PRESSURE WILL BUILD OVER THE AREA SATURDAY
NIGHT AND LAST INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THE LAST OF THE CONVECTION HAS MOVED OFFSHORE...AND THE INSTABILITY
IS NOT FAR BEHIND. THE SURFACE FRONT HAS CROSSED MUCH OF THE AREA...
BUT THE AIRMASS CHANGE IS STILL BACK OVER WESTERN PENNSYLVANIA.
WINDS ARE FAIRLY LIGHT...AND THE LOW LEVEL REMAIN MOIST...ESPECIALLY
AREAS THAT RECEIVED RAIN THURSDAY AFTERNOON AND EVENING. THE COMBINATION
IS ALLOWING FOG TO FORM (ALREADY 1/4SM FG AT KFWN). THE FOG WAS
HIT A BIT HARDER FOR THE EARLY MORNING UPDATE. AT THIS POINT...WITH
THE AIRMASS SLOWLY MODIFYING....THE FOG SHOULD NOT BE AS DENSE AS
THURSDAY MORNING...NOR SHOULD IT BE AS WIDESPREAD.
THE MID LEVEL SHORT WAVE THAT WILL HELP USHER IN THE AIRMASS
CHANGE IS ABOUT TO DROP INTO THE LONG WAVE TROUGH POSITION OVER
THE FORECAST AREA. WITH SOME INSTABILITY LINGERING...IT IS
POSSIBLE THAT SMALL CONVECTIVE CELLS COULD FORM JUST EAST OF THE
AREA BEFORE ABOUT 0900 UTC...FOSTERED BY FAIRLY STEEP MID LEVEL
LAPSE RATES. THE LATEST HRRR DOES SHOW SOME LIGHT SHOWER ACTIVITY
ACROSS THE SOUTHERN POCONOS AND UPPER LEHIGH VALLEY DURING THE
NEXT COUPLE OF HOURS WITH THE SHORT WAVE...BUT THERE IS NOTHING
UPSTREAM...SO THIS LOOKS OVERDONE. WE WILL CONTINUE THE DRY
FORECAST OVERNIGHT.
NOT MUCH WAS MADE IN THE WAY OF BIG CHANGES TO THE TEMPERATURE AND
WIND FORECASTS OVERNIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THIS EVENING/...
ON THURSDAY, HIGH PRESSURE WILL BUILD ACROSS THE EAST COAST, WHILE
SLIGHT RIDGING TAKES PLACE ALOFT. THIS WILL PROVIDE A WARM AND DRY
WEST-NORTHWEST FLOW ACROSS THE AREA. IN FACT, DEWPOINTS MAY MIX DOWN
INTO THE 50S ACROSS MUCH OF THE AREA DURING THE AFTERNOON, AND EVEN
THOUGH TEMPERATURES ARE FORECAST TO RISE INTO THE MID/UPPER 80S,
EVEN AROUND 90 IN SOME AREAS, IT SHOULD FEEL QUITE NICE. WITH MOSTLY
CLEAR SKIES, THE FORECAST WILL REMAIN POP LESS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
THE UPPER FLOW REMAINS SOMEWHAT FLAT...WITH A SLIGHT TROUGH ACROSS
THE EAST AND A RIDGE OUT WEST. DURING THE LONG RANGE...THE PATTERN
AMPLIFIES WITH A UPPER LOW SPINNING ACROSS HUDSON`S BAY THIS WEEKEND
WHICH WILL WEAKEN EARLY NEXT WEEK. THIS WILL KEEP OUR AREA IN AN
UNSETTLED PATTERN WITHOUT MUCH IN THE WAY OF EXCESSIVELY WARM
TEMPERATURES. IN FACT...TEMPERATURES FROM SATURDAY INTO EARLY NEXT
WEEK WILL BE NORMAL...OR PERHAPS A FEW DEGREES BELOW NORMAL. IT WILL
STILL BE WARM ON FRIDAY...HOWEVER...WITH MID TO UPPER 80S IN MOST
AREAS. A COLD FRONT WILL CROSS THE AREA LATER FRIDAY...BRINGING AN
END TO THE VERY WARM TEMPERATURES.
A FEW THUNDERSTORMS WILL ACCOMPANY THE FRONT FRIDAY AND FRIDAY
NIGHT. MY FORECAST HAS SLOWED THE START TIME FOR THE RAIN A BIT
COMPARED TO THE PREVIOUS FCST...BUT NOT BY MUCH. THE NAM SUGGESTS
THE RAIN WILL BEGIN TOWARDS EVENING...WHILE THE GFS HAS SOME SHOWERS
DEVELOPING AHEAD OF THE FRONT IN NJ FRI MORNING. THE 00Z EC MODEL IS
QUITE A BIT SLOWER...BRINGING THE SHOWERS IN SAT MORNING. WE WILL
OFFER CHC POPS FOR FRI NIGHT INTO SAT...WITH THE SAT ACTIVITY MOSTLY
IN THE MORNING.
FAIR WEATHER RETURNS FOR SAT NIGHT INTO SUNDAY AS HIGH PRESSURE
BUILDS BACK OVER THE AREA. THE REMAINDER OF THE EXTENDED FCST LOOKS
MOSTLY DRY...BUT THE UPPER TROUGH LINGERING TO THE WEST WILL OFFER
SMALL CHCS FOR A FEW SHOWERS AND MAYBE A TSTM MON-TUE. ONLY SLGT CHC
POPS ARE IN THE GRIDS FOR THESE TIME PERIODS ATTM. TEMPERATURES WILL
REMAIN NEAR NORMAL WITH HIGHS MOSTLY IN THE LOW TO MID 80S AND LOWS
IN THE MID 50S TO LOW 60S.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
MAINLY VFR CONDITIONS CONTINUE EARLY THIS MORNING UNDER MAINLY CLEAR
SKIES. PATCHY MVFR FOG IS EXPECTED (AS IT ALREADY OCCURRING AT
KMIV)...AND THIS SHOULD AFFECT KRDG...KTTN AND KILG BETWEEN 0800 AND
1200 UTC.
VFR CONDITIONS ARE EXPECTED TODAY. A FEW CUMULUS ARE POSSIBLE
ACROSS THE LEHIGH VALLEY AND PORTIONS OF NORTHWEST AND NORTH CENTRAL
NEW JERSEY...OTHERWISE SKIES SHOULD BE CLEAR. A NORTH TO NORTHWEST
FLOW BETWEEN 8 AND 12 KNOTS IS EXPECTED THIS MORNING...AND THE FLOW
SHOULD BEND BACK TO AROUND WEST DURING THE AFTERNOON...WITH WINDS
CLOSER TO 10 KNOTS.
ANY CUMULUS WILL DISAPPEAR EARLY THIS EVENING...OTHERWISE MAINLY VFR
CONDITIONS ARE EXPECTED TONIGHT. LIGHT WINDS MAY ALLOW PATCHY MVFR
FOG TO FORM...BUT COVERAGE OF FOG SHOULD BE LESS THAN THIS MORNING.
OUTLOOK...
FRI...MOSTLY VFR.
FRI NIGHT INTO SATURDAY...MOSTLY VFR WITH SCATTERED SHOWERS/TSTMS.
LOWER CONDITIONS POSSIBLE.
SAT NIGHT INTO MONDAY...MOSTLY VFR.
&&
.MARINE...
CONDITIONS ON THE WATERS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT
ADVISORY THROUGH THURSDAY. WINDS WILL SHIFT TOWARD THE NORTHWEST
BEHIND THE COLD FRONT AS IT CROSSES THE WATERS TONIGHT. WINDS MAY
GUST NEAR 15-20 KNOTS FOR A PERIOD TONIGHT, BUT SHOULD REMAIN BELOW
ADVISORY LEVELS.
OUTLOOK...
A COLD FRONT WILL CROSS THE WATERS LATER FRIDAY INTO EARLY
SATURDAY. IT WILL BE ACCOMPANIED BY SCATTERED SHOWERS/TSTMS.
CONDITIONS SHOULD REMAIN SUB-SCA THROUGH THE PERIOD.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...HAYES/HEAVENER
SHORT TERM...ROBERTSON
LONG TERM...O`HARA
AVIATION...HAYES/O`HARA
MARINE...ROBERTSON
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1228 AM EDT THU AUG 16 2012
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM AND WEAK LOW PRESSURE ACROSS THE AREA
LATE THIS AFTERNOON WILL MOVE TO THE EAST OVERNIGHT. THIS WILL ALLOW
HIGH PRESSURE FROM THE OHIO VALLEY TO BUILD ACROSS THE REGION. THIS
HIGH WILL REMAIN THROUGH FRIDAY EVENING...BEFORE A COLD FRONT
CROSSES THE AREA. THIS FRONT WILL SLOW DOWN AS IT MOVES OFF THE
COAST SATURDAY. MORE HIGH PRESSURE WILL BUILD OVER THE AREA SATURDAY
NIGHT AND LAST INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THE LAST OF THE CONVECTION HAS MOVED OFFSHORE...AND THE INSTABILITY
IS NOT FAR BEHIND. THE SURFACE FRONT HAS CROSSED MUCH OF THE AREA...
BUT THE AIRMASS CHANGE IS STILL BACK OVER WESTERN PENNSYLVANIA.
WINDS ARE FAIRLY LIGHT...AND THE LOW LEVEL REMAIN MOIST...ESPECIALLY
AREAS THAT RECEIVED RAIN THURSDAY AFTERNOON AND EVENING. THE COMBINATION
IS ALLOWING FOG TO FORM (ALREADY 1/4SM FG AT KFWN). THE FOG WAS
HIT A BIT HARDER FOR THE EARLY MORNING UPDATE. AT THIS POINT...WITH
THE AIRMASS SLOWLY MODIFYING....THE FOG SHOULD NOT BE AS DENSE AS
THURSDAY MORNING...NOR SHOULD IT BE AS WIDESPREAD.
THE MID LEVEL SHORT WAVE THAT WILL HELP USHER IN THE AIRMASS
CHANGE IS ABOUT TO DROP INTO THE LONG WAVE TROUGH POSITION OVER
THE FORECAST AREA. WITH SOME INSTABILITY LINGERING...IT IS
POSSIBLE THAT SMALL CONVECTIVE CELLS COULD FORM JUST EAST OF THE
AREA BEFORE ABOUT 0900 UTC...FOSTERED BY FAIRLY STEEP MID LEVEL
LAPSE RATES. THE LATEST HRRR DOES SHOW SOME LIGHT SHOWER ACTIVITY
ACROSS THE SOUTHERN POCONOS AND UPPER LEHIGH VALLEY DURING THE
NEXT COUPLE OF HOURS WITH THE SHORT WAVE...BUT THERE IS NOTHING
UPSTREAM...SO THIS LOOKS OVERDONE. WE WILL CONTINUE THE DRY
FORECAST OVERNIGHT.
NOT MUCH WAS MADE IN THE WAY OF BIG CHANGES TO THE TEMPERATURE AND
WIND FORECASTS OVERNIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THIS EVENING/...
ON THURSDAY, HIGH PRESSURE WILL BUILD ACROSS THE EAST COAST, WHILE
SLIGHT RIDGING TAKES PLACE ALOFT. THIS WILL PROVIDE A WARM AND DRY
WEST-NORTHWEST FLOW ACROSS THE AREA. IN FACT, DEWPOINTS MAY MIX DOWN
INTO THE 50S ACROSS MUCH OF THE AREA DURING THE AFTERNOON, AND EVEN
THOUGH TEMPERATURES ARE FORECAST TO RISE INTO THE MID/UPPER 80S,
EVEN AROUND 90 IN SOME AREAS, IT SHOULD FEEL QUITE NICE. WITH MOSTLY
CLEAR SKIES, THE FORECAST WILL REMAIN POP LESS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
THE UPPER FLOW REMAINS SOMEWHAT FLAT...WITH A SLIGHT TROUGH ACROSS
THE EAST AND A RIDGE OUT WEST. DURING THE LONG RANGE...THE PATTERN
AMPLIFIES WITH A UPPER LOW SPINNING ACROSS HUDSON`S BAY THIS WEEKEND
WHICH WILL WEAKEN EARLY NEXT WEEK. THIS WILL KEEP OUR AREA IN AN
UNSETTLED PATTERN WITHOUT MUCH IN THE WAY OF EXCESSIVELY WARM
TEMPERATURES. IN FACT...TEMPERATURES FROM SATURDAY INTO EARLY NEXT
WEEK WILL BE NORMAL...OR PERHAPS A FEW DEGREES BELOW NORMAL. IT WILL
STILL BE WARM ON FRIDAY...HOWEVER...WITH MID TO UPPER 80S IN MOST
AREAS. A COLD FRONT WILL CROSS THE AREA LATER FRIDAY...BRINGING AN
END TO THE VERY WARM TEMPERATURES.
A FEW THUNDERSTORMS WILL ACCOMPANY THE FRONT FRIDAY AND FRIDAY
NIGHT. MY FORECAST HAS SLOWED THE START TIME FOR THE RAIN A BIT
COMPARED TO THE PREVIOUS FCST...BUT NOT BY MUCH. THE NAM SUGGESTS
THE RAIN WILL BEGIN TOWARDS EVENING...WHILE THE GFS HAS SOME SHOWERS
DEVELOPING AHEAD OF THE FRONT IN NJ FRI MORNING. THE 00Z EC MODEL IS
QUITE A BIT SLOWER...BRINGING THE SHOWERS IN SAT MORNING. WE WILL
OFFER CHC POPS FOR FRI NIGHT INTO SAT...WITH THE SAT ACTIVITY MOSTLY
IN THE MORNING.
FAIR WEATHER RETURNS FOR SAT NIGHT INTO SUNDAY AS HIGH PRESSURE
BUILDS BACK OVER THE AREA. THE REMAINDER OF THE EXTENDED FCST LOOKS
MOSTLY DRY...BUT THE UPPER TROUGH LINGERING TO THE WEST WILL OFFER
SMALL CHCS FOR A FEW SHOWERS AND MAYBE A TSTM MON-TUE. ONLY SLGT CHC
POPS ARE IN THE GRIDS FOR THESE TIME PERIODS ATTM. TEMPERATURES WILL
REMAIN NEAR NORMAL WITH HIGHS MOSTLY IN THE LOW TO MID 80S AND LOWS
IN THE MID 50S TO LOW 60S.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
WE SHOULD BE VFR TONIGHT WITH JUST OUR USUAL TERMINALS HAVING SOME
LINGERING MVFR VSBYS EARLY TOMORROW MORNING WITH TODAY`S ADDED
RAIN. IT SHOULD BE NOTED THAT ONLY THE TERMINALS THAT SAW RAIN
TODAY WILL HAVE THESE ISSUES. THOUGH DRIER AIR IS WORKING INTO THE
REGION FROM THE NORTHWEST IT WILL TAKE A WHILE FOR THE NEWLY
ADDED, RAINFALL, MOISTURE TO DRY OUT. HAVE HIT TTN A BIT HARDER IN
TERMS OF VSBYS TONIGHT AND DROPPED THEM TO IFR THROUGH SUNRISE
TOMORROW.
FOG WILL BURN OFF AND VSBYS WILL REBOUND BACK TO VFR BY 14 OR 15Z
EVERYWHERE WHILE THE SKIES WILL REMAIN CLEAR. WINDS WILL SHIFT
MORE TOWARDS THE NORTHWEST BY DAYBREAK AND THEN MORE TOWARDS THE
WEST BY THE MID-AFTERNOON, ALL REMAINING UNDER 10 KNOTS.
OUTLOOK...
THU NIGHT INTO FRI...MOSTLY VFR.
FRI NIGHT INTO SATURDAY...MOSTLY VFR WITH SCATTERED SHOWERS/TSTMS.
LOWER CONDITIONS POSSIBLE.
SAT NIGHT INTO MONDAY...MOSTLY VFR.
&&
.MARINE...
CONDITIONS ON THE WATERS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT
ADVISORY THROUGH THURSDAY. WINDS WILL SHIFT TOWARD THE NORTHWEST
BEHIND THE COLD FRONT AS IT CROSSES THE WATERS TONIGHT. WINDS MAY
GUST NEAR 15-20 KNOTS FOR A PERIOD TONIGHT, BUT SHOULD REMAIN BELOW
ADVISORY LEVELS.
OUTLOOK...
A COLD FRONT WILL CROSS THE WATERS LATER FRIDAY INTO EARLY
SATURDAY. IT WILL BE ACCOMPANIED BY SCATTERED SHOWERS/TSTMS.
CONDITIONS SHOULD REMAIN SUB-SCA THROUGH THE PERIOD.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...HAYES
SHORT TERM...ROBERTSON
LONG TERM...O`HARA
AVIATION...HEAVENER/ROBERTSON/O`HARA
MARINE...ROBERTSON
AREA FORECAST DISCUSSION
NWS TOPEKA KS
241 AM CDT THU AUG 16 2012
.DISCUSSION...
UPPER TROF SLIDING ACROSS THE UPPER MIDWEST AND GENERATING ROUND
OF SHOWERS AND THUNDERSTORMS TO OUR NORTH AND EAST. SOUTHERN END
OF THE SURFACE FRONT SLIDING ACROSS THE CWA ATTM BRINGING GUSTY
WINDS AS IT PASSES. SHOWER ACTIVITY ALSO NOTED DEVELOPING OVER
WESTERN KS AND CENTRAL NEBRASKA ATTM WHILE THE REMAINDER OF
CENTRAL AND EASTERN KANSAS REMAINS DRY.
FOR TODAY...THINK TOO MUCH DRY AIR IN THE LAYER COUPLED WITH THE
LAG OF BETTER LIFT BACK SO FAR NW OF THE SURFACE FRONT HAS LEFT
THE INITIAL FRONTAL PUSH DRY FOR OUR AREA. ISENTROPIC CHARTS WOULD
SUGGEST POTENTIAL FOR SOME SHOWERS LATER THIS MORNING AND WILL
LEAVE JUST ISOLATED CHANCES AT THIS TIME. IF FRONT STALLS ACROSS
THE SOUTHEAST COUNTIES LATE THIS MORNING WOULD ANTICIPATE SOME
REDEVELOPMENT OF STORMS ALONG THE FRONT WHERE AFTERNOON MOISTURE
AND INSTABILITY POOL...BUT WILL DEPEND ON HOW FAR SOUTH THE FRONT
MAKES IT BEFORE LATE AFTERNOON. FOR NOW WILL CARRY POPS FROM
TOPEKA SOUTHEAST WITH BETTER CHANCES THE FARTHER SOUTHEAST YOU GO.
HIGHS SHOULD BE ON THE COOL SIDE WITH THE FRONT ALMOST TO MHK AT
THIS HOUR...WITH 70S NORTHWEST AND LOWER 80S SOUTHEAST. LOWS
TONIGHT RANGE FROM LOWER 50S NW TO UPPER 50S SE.
FRI/SAT/SUN...AIRMASS REMAINS ON THE COOL SIDE OF NORMAL THROUGH
THE WEEKEND WITH HIGHS IN THE LOWER 80S FOR MUCH OF THE AREA. EC
SUGGESTS LATE DAY CONVECTION ON THE HIGH PLAINS FRIDAY STAYS WEST
OF THE AREA. LEFT SOME SLIGHT CHANCES WEST THEN SOUTHWEST FOR
SATURDAY AND SATURDAY NIGHT AS ANOTHER POTENTIAL SHORTWAVE MOVES
THROUGH THE FLOW.
TEMPERATURES SLOWLY RISE MONDAY INTO TUESDAY AS SOUTHERLY FLOW
AROUND THE SURFACE HIGH RETURNS TO THE PLAINS..WITH MIDDLE 80S
MONDAY AND A FEW DEGREES WARMER TUESDAY. AGAIN LEFT SOME SLIGHT
CHANCE POPS WEST ON TUESDAY WITH NEXT SHORTWAVE. 67
&&
.AVIATION...
HIRES HRRR/NMM CONTINUE TO SHOW ISOLATED TO WIDELY SCATTERED
CONVECTION ALONG OR JUST AHEAD OF THE FRONT. THIS SEEMS TO BE
SUPPORTED BY RADAR TRENDS OVER THE LAST FEW HOURS. SO CONFIDENCE IN
CONVECTION ACTUALLY AFFECTING A GIVEN TERMINAL IS MARGINAL AT THIS
POINT AND WILL MAINTAIN A VCTS. THE GFS IS HINTING AT SOME MVFR CIGS
MOVING IN BEHIND THE FRONT. THE RAP AND NAM SHOW LOWER HUMIDITIES AT
925MB SUGGESTING A BKN DECK IS LESS LIKELY. WILL MENTION A SCT MVFR
DECK WITH THE FROPA...BUT THE MID SHIFT MAY NEED TO WATCH THIS AND
INCLUDE A TEMPO FOR MVFR CIGS IF IT LOOKS LIKE LOW CLOUDS ARE
DEVELOPING AS THE GFS SHOWS.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1128 PM CDT WED AUG 15 2012
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
HIRES HRRR/NMM CONTINUE TO SHOW ISOLATED TO WIDELY SCATTERED
CONVECTION ALONG OR JUST AHEAD OF THE FRONT. THIS SEEMS TO BE
SUPPORTED BY RADAR TRENDS OVER THE LAST FEW HOURS. SO CONFIDENCE IN
CONVECTION ACTUALLY AFFECTING A GIVEN TERMINAL IS MARGINAL AT THIS
POINT AND WILL MAINTAIN A VCTS. THE GFS IS HINTING AT SOME MVFR CIGS
MOVING IN BEHIND THE FRONT. THE RAP AND NAM SHOW LOWER HUMIDITIES AT
925MB SUGGESTING A BKN DECK IS LESS LIKELY. WILL MENTION A SCT MVFR
DECK WITH THE FROPA...BUT THE MID SHIFT MAY NEED TO WATCH THIS AND
INCLUDE A TEMPO FOR MVFR CIGS IF IT LOOKS LIKE LOW CLOUDS ARE
DEVELOPING AS THE GFS SHOWS.
WOLTERS
&&
.PREV DISCUSSION.../ISSUED 343 PM CDT WED AUG 15 2012/
TONIGHT AND THURSDAY...FCST FOCUS REMAINS ON COLD FRONT AND
ASSOCIATED RAIN CHCS.
FAVOR THE NAM OVER THE GFS FOR THE SHORT TERM FCST GIVEN RECENT
VERIFICATION AND BIAS. EXPECT THE COLD FRONT TO SWEEP THROUGH THE
AREA IN THE 10Z TO 14Z TIME FRAME ON THU. STRONGER DYNAMICS WILL
LEAD TO MORE WIDESPREAD PRECIP TO THE NORTH OF THE AREA WHILE
FRONTAL FORCING SHOULD YIELD SOME SCT CONVECTION ACROSS THE CWA
MAINLY AFTER 06Z. TIMING OF FRONT DOES NOT SUGGEST MORE THAN 20 TO
30 PERCENT COVERAGE AND WILL KEEP RAIN CHCS LOWER THAN THE MAV/GFS
GUIDANCE.
BREEZY NORTH WINDS BEHIND THE FRONT SHOULD ARRIVE BY MORNING WITH
MAX TEMPS EXPECTED TO RISE CLOSER TO THE WARMER NAM GUIDANCE GIVEN
TIME OF YEAR AND EXPECTED CLOUD HTS. RAIN CHCS AFTER 12Z APPEAR SLIM
AND WILL CONTINUE TO UNDERCUT GFS GUIDANCE.
OMITT
FRIDAY THROUGH TUESDAY...CONTINUED NW FLOW PATTERN PERSISTS
THROUGH THE EXTENDED WITH TWO SHORTWAVE TROFS AFFECTING
NORTHEASTERN KANSAS THROUGH TUESDAY. BIGGEST FACTOR IN BOTH EVENTS
WILL BE THE ABILITY OF MOISTURE TO RETURN IN TIME TO BE AVAILABLE
FOR THE WEAK FRONTAL PASSAGES.
THE FIRST SYSTEM ROTATES AROUND A DEEP LOW PRESSURE SYSTEM ANCHORED
NEAR HUDSON BAY ON SATURDAY. A RELATIVELY NARROW BAND OF MOISTER
AND WEAK CONVERGENCE WILL REALLY LIMIT THE POTENTIAL OF THIS WAVE TO
PRODUCE WIDESPREAD PRECIPITATION. STILL...GIVEN IT MAY PASS DURING
THE AFTERNOON WITH SOME INSTABILITY TO TAP...LOWER CHANCES OF PRECIP
SEEM REASONABLE.
THE SECOND WAVE AGAIN MOVES IN FROM THE NORTHWEST OVERNIGHT MONDAY
INTO TUESDAY MORNING. THIS SYSTEM HAS A DECENT FETCH OF MOISTURE
INFLUX FROM THE SOUTH AS THE WAVE PASSES. LIMITING FACTOR WITH THIS
SYSTEM IS A LACK OF DECENT CONVERGENCE TO FOCUS PRECIPITATION.
HOWEVER...AN OVERNIGHT EVENT WITH A STRENGTHENING LOW LEVEL JET
AIDING ELEVATED THUNDERSTORMS LOOKS TO BE THE MOST LIKELY SCENARIO
AND HAVE KEPT PREVIOUS TREND OF PRECIPITATION CHANCES.
NO WILD SWINGS IN TEMPERATURE WITH ANY OF THE SYSTEM PASSAGES...BUT
EXPECT SLIGHTLY BELOW TEMPS FRIDAY THROUGH SUNDAY...AND NEAR NORMAL
MONDAY AND TUESDAY.
HARDING
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
600 AM EDT THU AUG 16 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 559 AM EDT THU AUG 16 2012
MAIN FCST PROBLEMS FOCUS ON COVERAGE OF SHRA/TSRA ALONG COLD FRONT
AS IT MOVES THROUGH CENTRAL/ERN UPR MI THIS MORNING INTO EARLY
AFTERNOON...POSSIBILITY OF LINGERING INSTABILITY SHRA AND LAKE
EFFECT SHRA IN WAKE OF FRONT THIS AFTERNOON INTO EARLY FRIDAY...AND
GOOD POTENTIAL FOR ADVISORY W-NW WINDS OVER THE KEWEENAW PENINSULA
THIS AFTERNOON INTO THIS EVENING AND THEN OVER SHORELINE AREAS OF
ALGER AND LUCE COUNTIES TONIGHT.
WV IMAGERY AND RUC ANALYSIS SHOWS WELL-DEFINED VIGOROUS NEG-TILT
SHORTWAVE TROUGH MOVING THROUGH NRN ONTARIO. AT THE SFC...A COLD
FRONT EXTENDS SOUTH FROM THIS SYSTEM THROUGH WRN UPR MI AND NW WI.
MOISTURE CONVERGENCE AND INSTABILITY ALONG THIS FRONT HAVE SUPPORTED
SCT SHRA/TSRA ALONG THIS FRONT OVER WRN UPR MI AND NOW OVR FAR
SCNTRL UPR MI IN THE PAST HR.
TODAY AND TONIGHT...SHOWERS AND ISOLD TSRA OVER NCNTRL UPR MI HAVE
DISSIPATED OR MOVED NORTH OVER LAKE SUPERIOR IN PAST HR AS
INSTABILITY HAS WEAKENED ALONG/AHEAD OF COLD FRONT. DYNAMICS WITH
ONTARIO SHORTWAVE WILL SUSTAIN SHOWERS OVER ERN LAKE SUPERIOR THIS
MORNING INTO EARLY AFTERNOON. RUC HAS FCST MLCAPES INCREASING TO
200-400 J/KG OVER THE EAST HALF OF FCST AREA LATE THIS MORNING ALONG
COLD FRONT WHICH SHOULD SUSTAIN SCT TO NMRS SHRA/TSRA INTO EARLY
AFTERNOON UNTIL COLD FRONT PASSES EAST. LINGERING WEAK DIURNAL
INSTABILITY IN LOW-LVLS AND STEEP SFC-8H LAPSE RATES AS NOTED ON
NAM/RUC FCST SNDGS COULD SUPPORT SOME ISOLD SHRA INTO THE EARLY
AFTERNOON AS MID-LVL TROUGH MOVES OVERHEAD. SOME SCT LAKE EFFECT
SHRA COULD ALSO DEVELOP THIS AFTERNOON OVER WRN COUNTIES IN CYCLONIC
NW FLOW AS LAKE SFC DELTA-T/S WILL INCREASE NEAR 13-14C AS 8H TEMPS
DROP TO 5-6C OVER WRN LAKE SUPERIOR.
BIGGER CONCERN MAY BE POTENTIAL FOR ADVISORY WINDS OVER THE KEWEENAW
PENINSULA AND SHORELINE AREAS OF ALGER LUCE COUNTIES THIS AFTERNOON
INTO TONIGHT. MODELS PARTICULARLY NAM SUGGEST AN AREA OF PRES RISES
(4-5 MB OVER 6HR PERIOD) COMBINED WITH PASSAGE OF SECONDARY COLD
FRONT AND INCREASING INSTABILITY SHOULD ALLOW 35-40 KT TO MIX TO
SFC. HAVE POSTED WIND ADVISORY OVER THE NRN HOUGHTON-KEWEENAW FOR
THIS AFTERNOON INTO THIS EVENING AND OVER SHORELINE AREAS OF ALGER
AND LUCE COUNTIES TONIGHT.
CONTINUED COLD ADVECTION AS 8H TEMPS DROP TO 3-5C TONIGHT IN
CYCLONIC NW FLOW WILL CONTINUE TO SUPPORT LINGERING LAKE EFFECT RAIN
SHOWERS DOWNWIND OF LAKE SUPERIOR ESPECIALLY OVER ERN COUNTIES WHERE
FETCH WILL BE LONGER ACROSS THE LAKE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 559 AM EDT THU AUG 16 2012
NAM SHOWS A CLOSED 500 MB LOW NEAR JAMES BAY ON FRIDAY AND IT DOES
NOT MOVE MUCH SAT NIGHT. A RIDGE OVER THE WESTERN U.S. SLOWLY MOVES
EAST INTO THE ROCKIES WITH TIME. THERE ARE ALSO NUMEROUS WEAK
SHORTWAVES ROTATING AROUND THE CLOSED 500 MB LOW OVER NE ONTARIO IN
THE DEEP TROUGH THAT IS OVER THE ERN U.S. TIMING THESE WILL BE
DIFFICULT AND THESE WEAK SHORTWAVES COULD KICK OFF SOME
SHOWERS...ESPECIALLY DIURNAL HEATING OF THE DAY SHOWERS. DID NOT
MAKE TOO MANY CHANGES TO THE GOING FORECAST. MADE JUST A FEW
ADJUSTMENTS TO TEMPERATURES HERE AND THERE. SLIGHT CHANCE POPS FOR
LATE FRI NIGHT INTO SATURDAY LOOK GOOD ESPECIALLY OVER THE EASTERN
CWA AS ANOTHER SHORTWAVE LOOKS TO BE MOVING THROUGH.
IN THE EXTENDED...GFS AND ECMWF HAVE A DEEP TROUGH OVER THE EASTERN
HALF OF N.A. WITH A RIDGE IN THE WESTERN HALF 12Z SUN. PATTERN DOES
NOT CHANGE UNTIL TUE WHEN THE RIDGE MOVES INTO THE ROCKIES AND THE
TROUGH OVER THE ERN U.S. STARTS TO HEAD EAST AND DE-AMPLIFY A BIT.
COLDER THAN NORMAL TEMPERATURES WILL BEGIN THE PERIOD WITH A SLOW
WARM-UP THIS PERIOD. WITH TROUGHING IN THE AREA THROUGH
MONDAY...DIURNAL SHOWERS ARE DEFINITELY POSSIBLE. A SHORTWAVE
AFFECTS THE AREA FOR WED AND WILL HAVE SLIGHT CHANCE TO LOW CHANCE
POPS IN. TEMPERATURES WARM BACK TO NEAR NORMAL ON TUE AND WED. WILL
CONTINUE DRY FOR MONDAY NIGHT AND TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 117 AM EDT THU AUG 16 2012
EXPECT VFR CONDITIONS AT TAF ISSUANCE AT ALL 3 TAF SITES...BUT THE
APRCH OF A COLD FNT EARLY THIS MRNG WL BRING THE THREAT OF SHRA AND
PERHAPS A TS. INCLUDED AN EXPLICIT MENTION OF TS ONLY AT IWD WHERE
LATEST ANALYSIS SHOWS SOMEWHAT GREATER INSTABILITY. FOLLOWING THE
FROPA...A WSHFT TO THE WNW WL ADVECT COOLER AND MOISTER LLVL AIR
INTO THE AREA...RESULTING IN SOME LO CLDS/MVFR CONDITIONS AND
STRENGTHENING WINDS. THE BEST CHC FOR IFR CONDITIONS AND STRONGER
WINDS WL BE AT THE MORE EXPOSED CMX SITE WITH A MORE PRONOUNCED
UPSLOPE WIND COMPONENT. EXPECT THESE LO CIGS TO SLOWLY LIFT DURING
THE DAY TO VFR. BUT MVFR CIGS MAY LINGER THRU THIS EVNG AT CMX...
WHERE WIND GUSTS MAY APRCH 35 KTS WITH THE APRCH OF AXIS OF COOLEST
AIR/MORE INSTABILITY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 559 AM EDT THU AUG 16 2012
AS A COLD FRONT MOVES THROUGH LAKE SUPERIOR THIS MORNING...EXPECT A
SHARP WIND SHIFT TO THE WEST FOLLOWING THIS FRONTAL PASSAGE. THE
ARRIVAL OF MUCH COOLER AIR IN THE WAKE OF THE FRONT OVER THE WARM
WATERS OF LAKE SUPERIOR WILL ALSO RESULT IN ENHANCED MIXING OVER THE
LAKE WITH W-NW WINDS UP TO 30 KTS AND GALES TO 40 KNOTS OVER MOST OF
LAKE SUPERIOR THIS AFTERNOON THROUGH TONIGHT AND HAVE POSTED A GALE
WARNING FOR THIS. EXPECT THE STRONGER NW WINDS TO SLOWLY SUBSIDE ON
FRI THRU THE WEEKEND AS THE PRES GRADIENT WEAKENS WITH BROAD HIGH
PRESSURE SETTLING OVER THE REGION. THERE IS ALSO AN INCREASED RISK
OF RIP CURRENTS IN MARQUETTE AND ALGER COUNTIES THROUGH FRIDAY WITH
STRONG NORTHWEST WINDS AND HIGH WAVES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND ADVISORY FROM 1 PM THIS AFTERNOON TO MIDNIGHT EDT TONIGHT
FOR MIZ001-003.
WIND ADVISORY FROM 9 PM THIS EVENING TO 8 AM EDT FRIDAY FOR
MIZ006-007.
LAKE SUPERIOR...
GALE WARNING FROM 10 PM THIS EVENING TO 11 AM EDT FRIDAY FOR
LSZ267.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 10 AM EDT FRIDAY FOR
LSZ264>266.
GALE WARNING FROM 1 PM THIS AFTERNOON TO 1 AM EDT FRIDAY FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...07
AVIATION...KC
MARINE...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
118 AM EDT THU AUG 16 2012
.UPDATE...
ISSUED AT 842 PM EDT WED AUG 15 2012
TENDED TO SLOW DOWN EWD PROGRESSION OF SHRA/TS NOW IN MN INTO WRN
UPR MI WITH LLVL SE FLOW TENDING TO MAINTAIN DRY LLVL AIR SHOWN ON
THE 00Z APX RAOB OVER THE CWA. THE 12Z CNDN MODEL APPEARS TO HAVE
THE BEST HANDLE ON THIS SLOWER EWD PROGRESSION. EVEN THOUGH VIGOROUS
DYNAMICS ASSOCIATED WITH POTENT SHRTWV MOVING E THRU THE NRN PLAINS
ARE ACTING ON THIS LINE OF SHRA/TS DURING PEAK HEATING TIME...SVR
STORMS HAVE BEEN FEW AND FAR BTWN IN MN. SINCE MODELS SHOW WEAKER
MUCAPES IN THE 400-800 J/KG RANGE OVER THE CWA TNGT...SVR THREAT
SEEMS LO. DESPITE THE PRESENCE OF THIS LARGER SCALE DRY LLVL
AIR...THE 00Z GRB RAOB SHOWS AN AREA OF HIER MID LVL MSTR WITH KINX
OF 33. RADAR SHOWS SOME ISOLD -SHRA OVER NE WI MOVING TOWARD MNM
COUNTY AND HIER MUCAPE OVER THE SE CWA SHOWN ON THE SPC
MESOANALYSIS. SO INTRODUCED SOME ISOLD SHRA/TS OVER THE SE ZNS THRU
06Z. MAINTAINED THE INCRSG POPS LATER TNGT OVER THE CNTRL ZNS AS THE
CNDN MODEL SHOWS HIER QPF AFT 09Z AS DYNAMICS INTERACT WITH MORE
ABUNDANT MID LVL MSTR SHOWN ON THE GRB RAOB AND WSHFT TO THE SW
AHEAD OF APRCHG COLD FNT MIGHT ALLOW MORE LLVL MSTR TO ARRIVE.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 425 PM EDT WED AUG 15 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A POSITIVE TILT MID/UPPER
LEVEL TROUGH FROM NRN MANITOBA INTO ERN MT WITH A DOWNSTREAM RIDGE
FROM THE WRN GREAT LAKES INTO NRN ONTARIO. AT THE SFC...A COLD FRONT
EXTENDED THROUGH THE ERN DAKOTAS FROM LOW PRES OVER SE MANITOBA.
LIGHT SHOWERS OVER WRN WI THAT HAD DEVELOPED WITH WAA/305-310K
ISENTROPIC LIFT HAD DISSIPATED AS THEY MOVED INTO DRIER AIR TO THE
EAST...LEAVING MAINLY JUST BKN MID CLOUDS UPSTREAM OVER NW WI. SCT
SHRA/TSRA HAD ALSO DEVELOPED AHEAD OF THE FRONT OVER NW MN.
TONIGHT AND THURSDAY...EVEN THOUGH THE NAM/RUC SEEM OVERDONE WITH
THE AMOUNT OF WAA PCPN INTO THE AREA LATE THIS AFTERNOON AND
EVENING...COMPARED TO CURRENT TRENDS...CANNOT RULE OUT SOME LIGHT
SHOWERS DEVELOPING OVER THE WEST THIS EVENING WHERE SLIGHT CHANCE
POPS WERE RETAINED. OTHERWISE...MORE WIDESPREAD PCPN SHOULD MOVE
INTO THE CWA...MAINLY AFT 06Z AS THE MODELS HAVE TRENDED TOWARD A
SLOWER ARRIVAL OF GREATEST SHRA/TSRA CHANCES. FAVORABLE DYNAMICS
WITH 700-300 MB QVECTOR CONV AHEAD OF THE MID LEVEL TROUGH AND LOW
LEVEL CONV WITH THE FRONT SHOULD SUPPORT CATEGORICAL POPS LATE
TONIGHT INTO THURSDAY MORNING. THE SHRA/TSRA SHOULD EXIT CNTRL UPPER
MI IN THE MORNING AND THE ERN CWA DURING THE EARLY AFTERNOON. THERE
IS LESS CONFIDENCE WITH POTENTIAL FOR HIGHER PCPN AMOUNTS OR SEVERE
WEATHER AS THE GREATER MOISTURE INFLOW AND INSTABILITY WILL REMAIN
FARTHER SOUTH OVER WI.
STRENGTHENING WIND FIELDS WITH 0-6KM SHEAR VALUES INTO THE 30-35 KT
ARE EXPECTED AS THE SHRA/TSRA ARRIVES BUT MAY LAG THE BEST LOW LEVEL
FORCING. NEVERTHELESS THERE IS LIMITED SVR POTENTIAL WITH MUCAPE
VALUES FCST INTO THE 500-1000 J/KG RANGE. IF STRONGER LINEAR
CONVECTIVE AREAS SURVIVE AS THEY MOVE OUT OF MN AND NW WI...SOME
DAMAGING WIND GUSTS MAY BE POSSIBLE AS THE MAIN HAZARD...PER SPC.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 425 PM EDT WED AUG 15 2012
TEMPERATURES THROUGH THE EXTENDED WILL REMAIN BELOW NORMAL WITH A
WARMING TREND BEGINNING LATE IN THE PERIOD.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...THE UPPER LEVEL AND SURFACE
LOW WILL BECOME VERTICALLY STACKED THURSDAY NIGHT INTO FRIDAY AS THE
LOW SHIFTS FROM CENTRAL ONTARIO NORTH AND EASTWARD TO JAMES BAY. AS
THIS HAPPENS THE UPPER LEVEL TROUGH AXIS WILL SWING ACROSS UPPER
MICHIGAN. THE COOLER AIR ALOFT ASSOCIATED WITH THIS TROUGH WILL HELP
TO CREATE CONDITIONS FAVORABLE FOR LAKE EFFECT RAIN SHOWERS ACROSS
MAINLY CENTRAL PORTIONS OF UPPER MICHIGAN. H850 TEMPS ARE PROGGED TO
BE AROUND 4 TO 6C WITH SURFACE TEMPS AROUND 18 TO 19C ACROSS THE
AREA...WHICH SHOULD CREATE A LARGE ENOUGH TEMPERATURE DIFFERENCE TO
CAUSE THE LAKE EFFECT RAIN SHOWERS TO FORM. ALONG WITH THE RAIN
SHOWERS...HIGH WINDS ARE ALSO POSSIBLE OVER THE LAKE THURSDAY
AFTERNOON INTO THURSDAY NIGHT AS 30 TO 35 KNOT WINDS...AS SHOWN BY
THE EC/GFS...MIX DOWN TO THE LAKE SURFACE. AS THE UPPER LEVEL LOW
SHIFTS NORTHEASTWARD AND THE UPPER LEVEL TROUGH AXIS SHIFTS PAST THE
UPPER PENINSULA FRIDAY NIGHT...H850 TEMPS ARE EXPECTED TO
WARM...EFFECTIVELY REDUCING THE LAKE EFFECT RAIN SHOWER CHANCES. A
COOL NIGHT IS IN STORE FOR FRIDAY NIGHT AS WINDS BECOME LIGHT AND
SKIES BECOME MOSTLY CLEAR. TEMPERATURES AREA EXPECTED TO BE IN THE
LOW TO MID 40S ACROSS MAINLY INLAND AREAS...WITH A FEW OF THE USUAL
COOL SPOTS POTENTIALLY FALLING INTO THE UPPER 30S.
SATURDAY THROUGH MONDAY...A WEAK COLD FRONT WILL PUSH SOUTHWARD INTO
THE U.P. SATURDAY AFTERNOON THROUGH SUNDAY. A 500MB SHORTWAVE IS
ALSO PROGGED TO MOVE THROUGH THE AREA SATURDAY NIGHT THROUGH
MONDAY...AS IT ROTATES AROUND THE LOW CENTERED OVER JAMES BAY. THIS
SHOULD PROVIDE ENOUGH FORCING FOR A FEW SHOWERS TO DEVELOP THROUGH
THIS TIME PERIOD...HOWEVER...MOISTURE SHOULD BE FAIRLY LIMITED AS A
SURFACE HIGH PRESSURE SYSTEM WILL REMAIN CENTERED TO THE SOUTH
SOUTHWEST OF THE AREA KEEPING DRIER AIR ADVECTING INTO THE AREA FROM
THE WEST.
MONDAY NIGHT THROUGH WEDNESDAY...AS THE UPPER LEVEL LOW BEGINS TO
DRIFT SLOWLY EASTWARD...A RIDGE BUILDING OVER MUCH OF THE PLAINS
STATES WILL BEGIN TO WEAKEN AS IT TRIES TO BUILD EASTWARD INTO THE
UPPER GREAT LAKES REGION. THIS SHOULD ALLOW TEMPERATURES TO INCREASE
TO NEAR NORMAL LEVELS BY TUESDAY AND INTO THE DAY WEDNESDAY. TUESDAY
NIGHT INTO WEDNESDAY BOTH THE GFS/EC HAVE A SHORTWAVE ROTATING
AROUND THE RIDGE ALONG WITH A SURFACE LOW JUST TO THE WEST OF THE
REGION...BRINGING THE NEXT CHANCE OF SHOWERS TO THE AREA.
HOWEVER...WITH CONSIDERABLE DIFFERENCES IN SURFACE LOW PLACEMENT AND
STRENGTH HAVE DECIDED TO STICK TO A CONSENSUS OF THE MODELS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 117 AM EDT THU AUG 16 2012
EXPECT VFR CONDITIONS AT TAF ISSUANCE AT ALL 3 TAF SITES...BUT THE
APRCH OF A COLD FNT EARLY THIS MRNG WL BRING THE THREAT OF SHRA AND
PERHAPS A TS. INCLUDED AN EXPLICIT MENTION OF TS ONLY AT IWD WHERE
LATEST ANALYSIS SHOWS SOMEWHAT GREATER INSTABILITY. FOLLOWING THE
FROPA...A WSHFT TO THE WNW WL ADVECT COOLER AND MOISTER LLVL AIR
INTO THE AREA...RESULTING IN SOME LO CLDS/MVFR CONDITIONS AND
STRENGTHENING WINDS. THE BEST CHC FOR IFR CONDITIONS AND STRONGER
WINDS WL BE AT THE MORE EXPOSED CMX SITE WITH A MORE PRONOUNCED
UPSLOPE WIND COMPONENT. EXPECT THESE LO CIGS TO SLOWLY LIFT DURING
THE DAY TO VFR. BUT MVFR CIGS MAY LINGER THRU THIS EVNG AT CMX...
WHERE WIND GUSTS MAY APRCH 35 KTS WITH THE APRCH OF AXIS OF COOLEST
AIR/MORE INSTABILITY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 425 PM EDT WED AUG 15 2012
AS A COLD FRONT MOVES THROUGH LAKE SUPERIOR...EXPECT A SHARP WIND
SHIFT TO THE W LATE TONIGHT AND THU FOLLOWING THIS FRONTAL PASSAGE.
THE ARRIVAL OF MUCH COOLER AIR IN THE WAKE OF THE FRONT OVER THE
WARM WATERS OF LAKE SUPERIOR WILL ALSO RESULT IN ENHANCED MIXING
OVER THE LAKE WITH W-NW WINDS UP TO 30 KTS AND POSSIBLE GALES TO 35
KNOTS OVER THE N CNTRL PORTION OF THE LAKE...FROM LATE THURSDAY
AFTERNOON THROUGH THURSDAY NIGHT WHERE A GALE WATCH WAS POSTED.
SINCE MODELS HAVE TRENDED STRONGER WITH THE LOW LEVEL WIND FIELDS
THERE IS ALSO THE POTENTIAL FOR THE WATCH TO BE EXPANDED AND OR A
WARNING ISSUED FOR A LARGER AREA OF THE LAKE. EXPECT THE STRONGER NW
WINDS TO SLOWLY SUBSIDE ON FRI THRU THE WEEKEND AS THE PRES GRADIENT
WEAKENS WITH BROAD HIGH PRESSURE SETTLING OVER THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM THIS AFTERNOON THROUGH LATE TONIGHT FOR LSZ264-
266.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...JLB
LONG TERM...KEC
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DULUTH MN
344 AM CDT THU AUG 16 2012
.SHORT TERM...MSAS SHOWS SFC FRNTL BDRY HAS PUSHED INTO ERN WISC
ZONES EARLY THIS MORNING. PRESSURE IS RISING RAPIDLY BEHIND FRONT
AND GUSTY W/NW WINDS ARE INCREASING. A LARGE CANOPY OF POST
FRONTAL LOW CLOUDS IS OCCURRING WITHIN A DEEP MOIST CIRCULATION
GENERATED BY MID LVL TROF STRETCHING FROM ONTARIO SOUTH TO NRN
IOWA. LATEST WV IMAGERY AND RAP ANALYSIS SHOWS A MID LVL SHORTWAVE
TROF MOVING TOWARDS NWRN MN. BEHIND THIS FEATURE...A SECONDARY
FRONTAL SYSTEM IS INDICATED BY THE 925H THETAE FIELD.
TODAY...SECONDARY SHORTWAVE WILL SWEEP SE QUICKLY THIS MORNING AND
EXIT THE NORTH SHORE OF LAKE SUPERIOR BY MIDDAY. SUFFICIENT MSTR
RESIDES WITHIN THE CYCLONIC FLOW TODAY SO SHOWERS WILL BE OCCURRING
ACROSS THE NRN MN ZONES. A BIT CHALLENGING TO PREDICT WHERE THE
PRECIP/NO PRECIP ZONE WILL LIE EXACTLY. CLOUDS WILL BE PREVALENT
IN MOST AREAS THROUGH 18Z...BEFORE A MORE SERIOUS CLEARING TREND
DEVELOPS. LATEST NAM12 FCST AND BUFKIT PROFILES INDICATE 25-35MPH
GUSTS ARE POSSIBLE TODAY. ALONG THE NORTH SHORE THIS AFTN LOCALIZED
HIGHER WINDS ARE POSSIBLE AS AIR DESCENDS FROM HIGHER ELEVATION OF
COOK/LAKE COUNTY DOWN TO LAKE FRONT. MOST SIGNIFICANT COLD
ADVECTION IN BDRY LYR IS FOCUSED OVER ARROWHEAD SO MAX TEMPS MAY
BE SIGNIFICANTLY LOWER THAN SWRN CWA WHERE MORE NEUTRAL ADVECTION
OCCURS BY AFTN.
TONIGHT/TOMORROW...NO MAJOR CHANGES MADE TO EXISTING FCST EXCEPT
TO LOWER POPS FRIDAY OVER ARROWHEAD. SFC HIGH WILL SLOWLY APPROACH
THE CWA AS DEEP UPPER TROF CRAWLS EAST. INHERITED MIN TEMPS LOOK A
BIT ON THE LOW SIDE CONSIDERING SOME AMOUNT OF MIXING IS IMPLIED
BY THE FCST SFC PRESS GRADIENT AND POTENTIAL FOR FEW MORE CLOUDS
IN NW FLOW ALOFT. CURRENT FCST VALUES ARE ON LOW EDGE OF LATEST
SREF 2M TEMP PLUMES SO WE MAY NEED SOME TWEAK UPWARDS IN LATER
FORECASTS. A MID LVL SHORTWAVE TROF WILL APPROACH THE BORDERLAND
AND THE ARROWHEAD LATE FRIDAY. MDL CONSENSUS IS THAT ANY PRECIP
WILL BE SLOW TO ARRIVE.
.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY...
SHORT WAVES ROTATING AROUND THE JAMES BAY UPPER TROUGH WILL PROVOKE
A FEW MOSTLY AFTERNOON AND EVENING SHOWERS OR THUNDERSTORMS ACROSS
THE AREA THROUGH THE COMING WEEKEND. A MORE ZONAL FLOW WILL DRY OUR
AREA OUT MONDAY AND TUESDAY. AFTERNOON TEMPERATURES AROUND 70 THIS
WEEKEND WILL WARM TO THE MID OR UPPER 70S MONDAY AND GET INTO THE
80S TUESDAY. A COLD FRONT FROM CENTRAL CANADA AND A DIGGING TROUGH
ALOFT WILL BRING SCATTERED THUNDERSTORMS WEDNESDAY AND THURSDAY.
.AVIATION...08/16/06Z ISSUANCE...
FRONTAL BOUNDARY IS SLOWLY PROGRESSING THROUGH THE FA WITH SHOWERS
AND STORMS AHEAD OF THE FRONT. A MIX OF HIGH END MVFR/LOW END VFR
CIGS/VSBYS IN THE VCNTY OF THE STORMS. BEHIND THE FRONT...MVFR CIGS
WITH AREAS OF -DZ UNTIL AROUND 18Z WHEN DRIER AIR BEGINS TO MOVE
INTO THE AREA WITH BUILDING HIGH PRESSURE LEADING TO VFR.
.POINT TEMPS/POPS...
DLH 64 45 68 49 / 10 0 10 10
INL 62 41 71 44 / 30 10 20 10
BRD 68 45 70 51 / 10 0 0 10
HYR 68 44 68 44 / 20 0 10 10
ASX 68 47 71 47 / 20 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LSZ121-
144>148.
&&
$$
SHORT TERM...CANNON
LONG TERM....EOM
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1210 AM CDT THU AUG 16 2012
.AVIATION...08/16/06Z ISSUANCE...
FRONTAL BOUNDARY IS SLOWLY PROGRESSING THROUGH THE FA WITH SHOWERS
AND STORMS AHEAD OF THE FRONT. A MIX OF HIGH END MVFR/LOW END VFR
CIGS/VSBYS IN THE VCNTY OF THE STORMS. BEHIND THE FRONT...MVFR CIGS
WITH AREAS OF -DZ UNTIL AROUND 18Z WHEN DRIER AIR BEGINS TO MOVE
INTO THE AREA WITH BUILDING HIGH PRESSURE LEADING TO VFR.
&&
.PREV DISCUSSION... /ISSUED 832 PM CDT WED AUG 15 2012/
UPDATE...THUNDERSTORMS HAVE WEAKENED CONSIDERABLY AS COLD FRONT
MOVES THROUGH A LARGELY STABLE ATMOPSHERE. STILL EXPECT STORMS
TO PERCOLATE THROUGH THE EVENING AHEAD OF THE FRONT UNTIL IT CLEARS
THE FA ROUGHLY AROUND 06Z. SAID STORMS ARE ONLY PRODUCING
BENEFICIAL RAINS AND OCCASIONAL LIGHTNING. NO GUSTY WINDS OR HAIL
HAVE BEEN REPORTED WITH THESE STORMS. HAVE UPDATED TO REMOVE
SEVERE WORDING.
PREV DISCUSSION... /ISSUED 307 PM CDT WED AUG 15 2012/
SHORT TERM...[NOW - THURSDAY NIGHT]
AT 20Z...THERE WAS A POTENT SHORTWAVE IN EASTERN MONTANA AND
WESTERN NORTH DAKOTA APPROACHING THE NORTHERN PLAINS...AND AN
ASSOCIATED MID/UPPER LEVEL TROUGH EXTENDING INTO CENTRAL CANADA.
AN ASSOCIATED SURFACE LOW WAS IN SOUTHEASTERN MANITOBA. A 70 TO 80
KNOT JET WAS ROUNDING THE BASE OF THE MID/UPPER LEVEL TROUGH. A
STRONG COLD FRONT IN ASSOCIATION WITH THE SURFACE LOW STRETCHED
FROM SOUTHEASTERN MANITOBA...THROUGH NORTHWESTERN MINNESOTA...AND
THROUGH EASTERN SOUTH DAKOTA. THE FA HAD SLIGHTLY GUSTY SOUTHERLY
WINDS. TEMPERATURES WERE IN THE MID TO UPPER 70S. DEW POINT
TEMPERATURES WERE STILL IN THE 50S ACROSS MUCH OF THE EASTERN
FA...BUT THEY WERE CLIMBING INTO THE LOW TO MID 60S ACROSS THE
WESTERN FA WITH THE INFLUX OF MOISTURE AHEAD OF THE APPROACHING
COLD FRONT. THERE WERE SHOWERS AND SOME STORMS STRETCHING FROM
SOUTHWESTERN ONTARIO...THROUGH NORTHWESTERN MINNESOTA...AND INTO
EAST CENTRAL NORTH DAKOTA.
THROUGH THIS EVENING...THE COLD FRONT IN WESTERN MINNESOTA IS
EXPECTED TO SWEEP ACROSS THE NORTHLAND LATE THIS AFTERNOON AND
THIS EVENING...AND ITS PASSAGE WILL LIKELY MEAN SHOWERS AND
THUNDERSTORMS FOR MUCH OF THE FA. THE MODELS CONTINUE TO BE IN
REASONABLE AGREEMENT WITH TIMING AND PCPN. THE INFLUX OF WARM
SOUTHERLY FLOW AHEAD OF THE FRONT...COUPLED WITH THE EXPECTED
SHEAR AND CAPE...COULD RESULT IN SOME SEVERE THUNDERSTORMS.
CONTINUE TO THINK THAT MORE DISCREET SHOWERS AND STORMS IN WESTERN
MINNESOTA THIS AFTERNOON WILL BEGIN TO MOVE INTO NORTHEASTERN
MINNESOTA LATE THIS AFTERNOON AND TAKE ON A MORE LINEAR STRUCTURE.
THIS IS BACKED UP BY RECENT RUNS OF THE WRF AND HRRR MODELS. THIS
WOULD SUGGEST THAT DAMAGING WINDS ARE THE GREATEST THREAT FOR THE
STORMS TONIGHT...AND THAT IS IN AGREEMENT WITH THE SLIGHT RISK OF
SEVERE WEATHER CURRENTLY OUT FROM THE STORM PREDICTION CENTER AND
ITS EMPHASIS ON DAMAGING WINDS. LARGE HAIL AND BRIEF DOWNPOURS OF
RAIN ARE BOTH CERTAINLY POSSIBLE TOO. MIXED LAYER CAPE VALUES OF
1000 TO 2000 J/KG...DEEP LAYER SHEAR OF 30 TO 50 KNOTS...AND
PRECIPITABLE WATER VALUES OF AROUND 1.5 INCHES ARE EXPECTED THIS
AFTERNOON WHEN THE COLD FRONT MOVES INTO THE WESTERN FA. SINCE
THIS COLD FRONT WILL BE MOVING FAIRLY QUICKLY...HEAVY RAIN IS NOT
TOO MUCH OF AN ISSUE DUE TO LACK OF THUNDERSTORMS RESIDENCE TIME
OR TRAINING. HOWEVER...THERE COULD CERTAINLY BE BRIEF DOWNPOURS
WITH THE RAIN. MUCH OF THE FA HAS BEEN GIVEN ABOUT A QUARTER TO
HALF INCH OF RAIN FOR THE FORECAST THROUGH THIS EVENING.
LATE TONIGHT...MUCH COOLER AIR WILL SWOOP INTO THE NORTHLAND LATE
TONIGHT IN THE WAKE OF THE FRONT. ANY REMAINING PCPN SHOULD
TRANSITION TO SHOWERS...BUT THERE MAY BE SOME LINGERING THUNDER
ACROSS THE FAR EASTERN FA.
THURSDAY...IT LOOKS LIKE A SOMEWHAT DREARY SUMMER DAY ACROSS THE
NORTHLAND. PARTLY TO MOSTLY CLOUDY SKIES...GUSTY NORTHWEST
WINDS...AND MUCH COOLER TEMPERATURES ARE EXPECTED IN THE WAKE OF
THE FRONT. MODEL SOUNDINGS SUGGEST WIND GUSTS OF 20 TO 30 MPH AT
TIMES. SHOWERS ARE POSSIBLE ACROSS NORTHERN MINNESOTA. THERE MAY
BE SOME LATE DAY SUNSHINE ACROSS THE WESTERN FA.
THURSDAY NIGHT...THE CLOUDS SHOULD GRADUALLY CLEAR AND THE WINDS
RELAX AS HIGH PRESSURE MOVES INTO THE NORTH CENTRAL US.
LONG TERM...[FRIDAY - TUESDAY]
PATTERN CHANGE TO A STRONGER UPPER LEVEL TROF ANCHORED OVER THE
CENTRAL GREAT LAKES THIS WEEKEND AND EARLY NEXT WEEK WILL LEAVE
THE DULUTH CWA UNDERNEATH COOL NW FLOW ALOFT AND WHAT WILL
PROBABLY FEEL LIKE EARLY FALL WEATHER AT TIMES. AS IS COMMON IN
PREVAILING NW FLOW ALOFT..A SERIES OF WEAK BUT AMPLIFYING
DISTURBANCES WILL DIVE SOUTHEASTWARD ACROSS OUR AREA INTO THE MAIN
TROF AXIS DURING THE SAT-MON TIME FRAME. RELATIVELY COOL TEMPS
ALOFT AND STEEP LOW-MID LEVEL LAPSE RATES WITH ANY DAYTIME SUN
SHOULD RESULT IN ISOLATED/SCATTERED SHOWERS AND PERHAPS A FEW
T-STORMS EACH DAY FRIDAY THRU SUNDAY. MODELS TYPICALLY HAVE A HARD
TIME RESOLVING INDIVIDUAL DISTURBANCES IN THIS FLOW REGIME BEYOND
48-60 HOURS..AND THIS SEEMS TO BE THE CASE THRU MONDAY AS THE WAVE
THAT SEEMS BEST RESOLVED RIGHT NOW TIMING/PLACEMENT WISE IS ON
FRIDAY.
EARLY NEXT WEEK LOOKS FAIRLY TRANQUIL WITH A SLOW WARMING TREND OF
A FEW DEGREES EACH DAY AS GREAT LAKES TROF SLOWLY DE-AMPLIFIES
AND FLOW ALOFT BECOMES MORE WESTERLY. THIS SHOULD EVENTUALLY ALLOW
MOISTURE TO SLOWLY INCREASE BY THE END OF THE 7 DAY FORECAST
PERIOD..WITH AT LEAST SMALL CHANCES FOR SHOWERS/TSTMS RETURNING
FROM WED/THUR.
&&
.POINT TEMPS/POPS...
DLH 45 69 51 70 / 0 30 20 20
INL 41 72 43 70 / 10 30 20 10
BRD 45 71 51 73 / 0 10 10 20
HYR 44 69 43 72 / 0 20 20 20
ASX 47 72 48 71 / 10 30 20 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...CANNON
LONG TERM....EOM
AVIATION...EOM
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1208 AM CDT THU AUG 16 2012
.AVIATION...06Z TAF. COLD FRONT HAS SWEPT THROUGH THE TERMINAL
WITH STEADY NORTHERLY WINDS IN ITS WAKE...WITH GUSTS NEAR 30KTS.
WINDS WILL BE STEADY DURING THE NIGHT...THEN WILL DECREASE DURING
THE DAY ON THURSDAY AS SURFACE RIDGE SETTLES SOUTH ONTO THE PLAINS
AND GRADIENT RELAXES. FOR THE MOST PART...INTERMITTENT MID LEVEL
CLOUDS ARE EXPECTED TO ARRIVE OVERNIGHT AND INTO THE DAY THURSDAY
AND MODELS INDICATE DEVELOPMENT OF SCATTERED SHOWERS WITH THE
PASSAGE OF THE MID/UPPER TROUGH. CONDFIDENCE IN PCPN ACTIVITY IS
NOT EXTREMELY HIGH BUT DID INCLUDE MENTION FOR KGRI. CLOUDS SHLD
SCATTER TOWARD EVENING.
&&
.PREV DISCUSSION... /ISSUED 939 PM CDT WED AUG 15 2012/
UPDATE...HAVE INCREASINGLY BEEN LOSING CONFIDENCE IN THUNDERSTORM
DEVELOPMENT THIS EVENING. THE HRRR AND 00Z NAM CONTINUE TO TRY AND
DEVELOP CONVECTION ALONG THE FRONT...BUT THUS FAR THIS HAS NOT
MATERIALIZED AND IT SEEMS LESS LIKELY THAT IT WILL EVER
MATERIALIZE IN AT LEAST AN IMPACTFUL WAY. IT IS APPEARING MORE
LIKELY THAT MOST AREAS WILL ONCE AGAIN SEE A DRY NIGHT...OR MAYBE
A FEW POST FRONTAL SHOWERS DURING THE EARLY MORNING HOURS. EVEN IF
POST FRONTAL SHOWERS DEVELOP...THEY WILL LIKELY NOT BE BIG
PRECIPITATION PRODUCERS. THEREFORE...HAD TO DRASTICALLY CUT POPS
FOR THE REMAINDER OF TONIGHT FOR MOST NEBRASKA ZONES. THERE HAVE
BEEN A FEW THUNDERSTORMS OVER KANSAS ZONES AND HAVE ACTUALLY
INCREASED POPS ACROSS OUR FAR SOUTHERN KANSAS ZONES.
PREV DISCUSSION... /ISSUED 338 PM CDT WED AUG 15 2012/
SHORT TERM...THROUGH 00Z FRIDAY. MORNING UPPER AIR ANALYSIS
INDICATES UPPER LEVEL RIDGING OVER THE SOUTHWESTERN
CONUS...TROUGHING OVER THE EAST...AND A MID LEVEL SHORT WAVE OVER
SOUTH-CENTRAL CANADA AND THE NORTHERN PLAINS. UPPER LEVEL JET
ENERGY IS ALSO NOTED MEANDERING NORTH AND SOUTH FROM SOUTHWESTERN
AND SOUTHERN CANADA...AS WELL AS THE NORTHERN PLAINS ON INTO THE
EASTERN CONUS...AND A ~50KT MID LEVEL JET STREAK IS NOTED OVER
PORTIONS OF THE NORTHERN PLAINS ON THE SOUTH/SOUTHEAST SIDE OF THE
APPROACHING MID LEVEL SHORT WAVE. WATER VAPOR IMAGERY INDICATES A
DEVELOPING TROPICAL TAP OVER THE SOUTHWESTERN CONUS...BUT THIS
MOISTURE REMAINS RELEGATED TO OUR SOUTHWEST WITH MID LEVEL
MOISTURE OVER OUR AREA PRIMARILY BEING PULLED IN FROM THE PACIFIC
NORTHWEST BY THE APPROACHING MID LEVEL SHORT WAVE. A SURFACE LOW
IS NOTED OVER NORTHERN MINNESOTA...AHEAD OF THE MID LEVEL SHORT
WAVE...AND A COLD FRONT EXTENDS SOUTH/SOUTHWESTWARD FROM THE LOW
ACROSS THE DAKOTAS INTO CENTRAL NEBRASKA...AND THEN INTO
NORTHWESTERN KANSAS AND EASTERN COLORADO. AS OF 19Z THIS FRONT WAS
NOTED EXTENDING FROM NEAR KANW...TO KTIF...KLBF AND NEAR KIML. LOW
LEVEL FLOW REMAINS FROM THE SOUTH ACROSS MUCH OF OUR CWA AS A
RESULT...WITH A NORTHWESTERLY LOW LEVEL WIND FIELD NOTED BEHIND
THE LOW LEVEL BAROCLINIC ZONE ACROSS THE HIGH PLAINS. VISIBLE
SATELLITE IMAGERY INDICATES VERY LITTLE IN THE WAY OF CLOUD COVER
ACROSS NEBRASKA...BUT HIGH LEVEL CLOUDS AHEAD OF THE MID LEVEL
SHORT WAVE ARE BEGINNING TO ENTER THE STATE FROM SOUTH DAKOTA.
SMOKE IS ALSO EVIDENT ON VISIBILITY SATELLITE IMAGERY...ORIGINATING
FROM THE WILDFIRES CURRENTLY BURNING ACROSS WESTERN PORTIONS OF
THE CONUS.
SHORT TERM GUIDANCE CONTINUES TO SUGGEST THE NORTHERN PLAINS MID
LEVEL SHORT WAVE WILL CONTINUE MOVING EAST/SOUTHEAST TONIGHT INTO
TOMORROW. THIS WILL ALLOW THE SURFACE LOW...CURRENTLY OVER
NORTHERN MINNESOTA...TO PUSH EAST THUS ALLOWING THE LOW LEVEL
BAROCLINIC ZONE TO ALSO SWEEP EAST ACROSS OUR CWA. QPF FIELDS FROM
THE 15/12Z NAM AND 4KM WRF-NMM...AS WELL AS THE 15/14Z HRRR
SUGGEST CONVECTION WILL INITIATE NEAR OUR WEST/NORTHWESTERN CWA
ALONG THE LOW LEVEL BAROCLINIC ZONE AROUND 00Z. ISOLATED TO
PERHAPS SCATTERED PRECIPITATION IS THEN EXPECTED TO PUSH
EAST/SOUTHEAST ACROSS THE CWA. THE BEST DPVA AND MID LEVEL THERMAL
ADVECTION IS EXPECTED TO REMAIN OVER THE UPPER MISSISSIPPI
VALLEY...BUT THE SOUTH/SOUTHWESTERN MOST EXTENT OF THIS OMEGA MAY
CLIP OUR NORTH/NORTHEASTERN CWA AND AS A
RESULT...NORTH/NORTHEASTERN PORTIONS OF OUR CWA APPEAR MOST
FAVORED FOR PRECIPITATION THIS EVENING INTO TONIGHT. LOWER POPS
EXIST FARTHER SOUTHWEST ACROSS THE CWA WHERE BROAD-SCALE OMEGA
WILL BE WEAKER...BUT LOW LEVEL CONVERGENCE AND RESULTANT FORCING
ALONG THE LOW LEVEL BAROCLINIC ZONE MAY BE STRONG ENOUGH FOR
CONVECTIVE INITIATING AND RESULTANT PRECIPITATION PRODUCTION.
GIVEN ALL THIS...WENT AHEAD WITH 20% POPS ACROSS OUR FAR
WEST/NORTHWEST 21Z-00Z...WITH 20%-60% POPS SPREADING ACROSS MUCH
OF THE REST OF THE CWA 00Z-06Z. AGAIN...THE HIGHEST POPS HAVE BEEN
RELEGATED TO OUR NORTHEASTERN CWA. THE 15/12Z NAM SUGGESTS 0-1KM
MLCAPE VALUES OF ~1500J/KG WILL BE IN EXISTENCE ACROSS MUCH OF THE
CWA THIS AFTERNOON AND EVENING...WITH DEEP LAYER BULK SHEAR VALUES
OF 20-30KTS ALSO IN EXISTENCE. GIVEN THIS IT CERTAINLY APPEARS THE
GREATER RISK FOR SEVERE WEATHER THIS AFTERNOON AND EVENING WILL
EXIST FARTHER NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY WHERE
GREATER VALUES OF INSTABILITY WILL BE OBSERVED...BUT AN ISOLATED
REPORT OF LARGE HAIL CANNOT BE RULED OUT ACROSS OUR AREA WITH THE
AFOREMENTIONED INSTABILITY IN PLACE. IN ADDITION...SIMULATED
REFLECTIVITY FIELDS FROM THE 15/12Z 4KM WRF-NMM SUGGEST A
QLCS...ALBEIT DISORGANIZED...COULD BE REALIZED ALONG THE LOW LEVEL
BAROCLINIC ZONE FROM THE UPPER MISSISSIPPI VALLEY INTO PORTIONS OF
THE MISSOURI RIVER VALLEY...WITH THE VERY SOUTHWESTERN EXTENT OF
THIS SYSTEM PERHAPS CLIPPING OUR NORTHEASTERN CWA. GIVEN ALL
THIS...WILL GO AHEAD AND CONTINUE TO CARRY SEVERE STORM WORDING IN
THE HWO FOR LATE THIS AFTERNOON THROUGH THIS EVENING...WITH
NORTHEASTERN PORTIONS OF OUR CWA THE MOST LIKELY AREA TO OBSERVE
SEVERE WEATHER ACROSS OUR AREA.
ANY SEVERE WEATHER THAT IS REALIZED SHOULD BE SHORT-LIVED AS THE
LOW LEVEL BAROCLINIC ZONE QUICKLY PUSHES AWAY FROM THE AREA BY 06Z
AND THE MID LEVEL TROUGH AXIS PUSHES WELL TO THE EAST/NORTHEAST OF
OUR AREA. THE OVERALL LACK IN KINEMATIC FORCING WOULD OTHERWISE
PRESENT DRY CONDITIONS TO THE AREA HEADING INTO THE DAY
THURSDAY...BUT SHORT TERM GUIDANCE SUGGESTS THE ~50KT MID LEVEL
JET STREAK TO OUR NORTHWEST WILL PUSH OVERHEAD TOMORROW...WITH A
DIRECT THERMAL CIRCULATION WITHIN THE RIGHT-REAR QUAD OF THIS JET
STREAK PERHAPS PROVIDING ENOUGH LIFT FOR ADDITIONAL PRECIPITATION
PRODUCTION DURING THE MORNING HOUR THURSDAY. WENT AHEAD WITH 20%
POPS ACROSS THE ENTIRE CWA THURSDAY MORNING AS A RESULT.
LOW LEVEL PRESSURE RISES POST-FROPA WILL CREATE A SIGNIFICANT
INCREASE IN THE LOW LEVEL PRESSURE GRADIENT FOR A BRIEF TIME THIS
EVENING...LIKELY RESULTING IN STRONG WINDS ACROSS PORTIONS OF OUR
CWA PRIMARILY DURING THE 00Z-09Z TIME FRAME. MET AND MAV GUIDANCE
BOTH SUGGEST WIND SPEEDS FOR A FEW LOCATIONS ACROSS THE CWA COULD
FLIRT WITH WIND ADVISORY CRITERIA FOR A TIME...BUT THESE STRONGEST
WINDS ARE EXPECTED TO REMAIN FAIRLY BRIEF AND SHOULD NOT REQUIRE
ANY HEADLINES THIS EVENING OR TONIGHT.
BCCONSRAW HAS BECOME ONE OF THE BETTER SETS OF GUIDANCE WITH
RESPECT TO OVERNIGHT LOWS THE PAST FEW DAYS AND THUS PLAYED
CLOSELY TO BCCONSRAW FOR OVERNIGHT LOWS TONIGHT. OVERNIGHT LOWS IN
THE 60S ARE FORECAST ACROSS MUCH OF THE CWA FOR TONIGHT AS A
RESULT. A MAJOR COOL DOWN IS IN STORE FOR THE AREA BEGINNING
TOMORROW AS A MUCH COOLER AIRMASS SETTLES INTO THE REGION.
STATISTICALLY...CONSMOS AND ADJMAVBC HAVE BEEN DOING VERY WELL
WITH DAY 1 HIGH TEMPERATURES...BUT THE ADJMAVBC LOOKED A LITTLE
WARM WITH HIGHS IN THE UPPER 70S TO LOWER 80S. WITH STRONG LOW
LEVEL COLD AIR ADVECTION...AS WELL AS LINGERING CLOUD COVER AND
POSSIBLE PRECIPITATION...WOULD MUCH RATHER KEEP DAY TIME
TEMPERATURE RISES TO AROUND 15 DEGREES ON THURSDAY...WHICH WOULD
PRESENT THURSDAY HIGHS IN THE MID TO UPPER 70S FOR THE MOST PART.
CONSMOS SEEMED TO HAVE A BETTER HANDLE ON THIS AND THUS WENT
CONSMOS FOR HIGHS ON THURSDAY.
LONG TERM...BEGINNING 00Z FRIDAY AND CONTINUING THROUGH
WEDNESDAY. MAIN CONCERNS FOR THIS PERIOD WILL BE TEMPERATURES AND
PRECIPITATION. FOG MAY BECOME AN ISSUE FRIDAY MORNING AS WELL.
STARTING WITH FRIDAY MORNING...LOW TEMPERATURES WILL BE THE
COOLEST LOWS OBSERVED THROUGHOUT THE LONG TERM AS TEMPERATURES
WILL BE 10 TO 15 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. A
STEADY INCREASE IN LOW TEMPERATURES EACH DAY WILL BE OBSERVED
THROUGH THE EXTENDED FORECAST...EVENTUALLY GETTING BACK TO NEAR
NORMAL LOW TEMPERATURES ON MONDAY. WENT WITH BCCONSRAW FOR FRIDAY
LOW TEMPS AND BCCONSALL FOR LOW TEMPS ON SATURDAY...BOTH CHANGES
INDUCED A SLIGHT LOWERING IN LOW TEMPERATURES FROM THE PREVIOUS
FORECAST. HIGH TEMPERATURES DURING THIS PERIOD WILL BEGIN BELOW
NORMAL AS WELL...WITH TEMPERATURES EVENTUALLY GETTING BACK TO
NORMAL ON MONDAY. WENT WITH THE PREVIOUS SHIFTS HIGH TEMPERATURES
FOR FRIDAY AND SATURDAY. ALLBLEND TOOK CARE OF THE FOLLOWING DAYS
WITH VERY REASONABLE OUTCOMES FOR BOTH LOW AND HIGH TEMPERATURES.
PRECIPITATION CHANCES WILL BEGIN AS EARLY AS FRIDAY EVENING AND
CONTINUE ON INTO SUNDAY MORNING AS A WEAK WAVE MOVES THROUGH THE
PLAINS. INITIALIZATION OF THE PRECIPITATION ACROSS SOUTHWESTERN
PARTS OF THE CWA FRIDAY EVENING ARE IN PRETTY GOOD AGREEMENT WITH
THE NAM12...GFS40...AND THE EC. SREF 6-HR QPF PROBABILITIES FOR
GREATER THAN 0.01 INCHES OF PRECIPITATION AT 00Z SATURDAY INDICATE
NEAR 50 PERCENT FOR NEARLY THE ENTIRE SOUTHWESTERN HALF OF THE
CWA. A LESS CLEAR PICTURE IS PAINTED AS DISAGREEMENT BETWEEN MODEL
OUTPUT WITH PRECIPITATION COVERAGE BECOMES EVIDENT LATER IN THE
DAY. LEANED MORE TOWARDS THE NAM SOLUTION FOR SATURDAY AND
ALLBLEND FOR SUNDAY MORNING. DEEP LAYER SHEAR AND SURFACE BASED
CAPE ARE WEAK...BUT LOW LEVEL SHEAR IS MODEST...WITH EARLY
AFTERNOON VALUES BETWEEN 15 AND 25 KTS/KM. THUNDERSTORMS ARE
POSSIBLE BUT SEVERE POTENTIAL IS VERY LIMITED AT THE MOMENT. THE
NEXT CHANCE FOR PRECIPITATION IS MONDAY EVENING LEADING INTO
TUESDAY MORNING...AND HAS BEEN THE CASE FOR PREVIOUS FORECAST
ACROSS THE CWA. THE GFS AND EC ARE IN PRETTY GOOD AGREEMENT FOR
PRECIPITATION ON TUESDAY MORNING. THUNDERSTORMS WILL BE POSSIBLE
WITH THIS SYSTEM ON TUESDAY.
SURFACE DEW POINT DEPRESSIONS WILL BE CLOSE TO 5 DEGREES OR LESS
FOR NORTHERN AND WESTERN PARTS OF THE CWA FRIDAY MORNING. MAY WANT
TO CONSIDER MONITORING FOG CONDITIONS TOMORROW EVENING AS THE
PICTURE BECOMES MORE CLEAR. MODELS ARE INDICATING A SURFACE HIGH
SITTING OVER THE NORTHERN/CENTRAL PLAINS...LIGHT WINDS ACROSS MUCH
OF THE OUTLOOK AREA FRIDAY MORNING...AND MOSTLY CLEAR SKIES WILL
HELP INDUCE FOG UNDER THESE CONDITIONS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1218 AM CDT THU AUG 16 2012
.AVIATION...
TSRA WILL APPROACH KCDS DURING THE FIRST SEVERAL HRS OF FORECAST.
IF CONVECTION CONTINUES CURRENT PROPAGATION TRENDS...TSRA MAY
IMPACT KCDS OR VCTY BTWN 09Z AND 11Z. ANY IMPACTS TO THE
TERMINAL SHOULD LAST LESS THAN AN HOUR AND WILL LIKELY NOT FALL
BELOW MVFR CAT. OTHERWISE...VFR CONDITIONS EXPECTED AT BOTH KLBB
AND KCDS THROUGH THE FORECAST PERIOD. JH
&&
.PREV DISCUSSION... /ISSUED 653 PM CDT WED AUG 15 2012/
AVIATION...
ALTHOUGH ISLD TSRA WILL APPROACH KLBB TERMINAL FROM THE WEST
THROUGH 16/06Z...DO NOT ANTICIPATE ANY IMPACTS. ADDITIONAL ISOLD
SHRA/TSRA WILL BE POSSIBLE ACROSS W TX THU AFTN...BEYOND 16/18Z.
HOWEVER...ANY POTENTIAL IMPACTS WILL BE BRIEF AND WILL LIKELY NOT
FALL BELOW MVFR CAT. OTHERWISE...VFR CONDITIONS EXPECTED AT BOTH
KLBB AND KCDS THROUGH THE FORECAST PERIOD. JH
PREV DISCUSSION... /ISSUED 313 PM CDT WED AUG 15 2012/
SHORT TERM...
WE HAVE SOME MIXED SIGNALS REGARDING TSTM CHANCES LATE THIS
AFTERNOON AND EVENING. ON ONE HAND...LOW MOISTURE HAS INCREASED
MARKEDLY OVER YESTERDAY AND WE REMAIN UNDERNEATH A WEST-EAST MID-LVL
MOISTURE AXIS AS WELL. ON THE OTHER HAND...THE MOISTURE HAS DELAYED
HEATING AND THE AREA WAS STILL CAPPED AS OF 2 PM. NW FLOW CONTINUES
ALOFT AND WATER VAPOR IMAGERY SHOWS THE NEXT SHORTWAVE MOVING INTO
NRN NM AT THIS TIME....WHICH IS HELPING TO INITIATE STORMS ALL ALONG
THE NEW MEXICO MTNS. THERE IS ALSO SOME CU DEVELOPMENT IN THE
EAST TO SOUTH-CENTRAL TX PANHANDLE ALONG A SFC TROUGH AND AS THE CAP
WEAKENS WE COULD SEE SOME STORMS DEVELOP ALONG THIS TROUGH INTO
THE FAR SRN PANHANDLE...POSSIBLY SWISHER AND BRISCOE COUNTIES.
FINALLY...WE HAVE ANOTHER WEAK SFC TROUGH NEAR THE TX-NM BORDER
WHICH COULD ALSO BE THE FOCUS FOR SOME STORM DEVELOPMENT WEST OF
HIGHWAY 214. SO WITH ALL THIS...WE HAVE A SLGT CHANCE GOING ACROSS
THE ENTIRE FA THIS AFTERNOON FOR THE POSSIBILITY OF SOME LOCAL
DEVELOPMENT. BUT WE EXPECT THE MAIN SHOW SO TO SPEAK TO BE LATER
THIS EVENING AS A BROKEN LINE/LOOSE COMPLEX OF STORMS MOVES
ROUGHLY E-SEWD OUT OF EASTERN NEW MEXICO....ACROSS THE SPLNS AND
POSSIBLY INTO THE ROLLING PLAINS TONIGHT. THE HRRR HAS BEEN RATHER
CONSISTENT IN THIS DEPICTION...WHILE MUCH OF THE OTHER GUIDANCE
WEAKENS THE ACTIVITY AS IT MOVES EAST. WITH THE UPPER WAVE
PROVIDING SOME BACKGROUND ASCENT AND A 30 TO 40 KT SRLY LLJ WE
CURRENTLY ANTICIPATE THE ACTIVITY MAKING IT AT LEAST INTO THE
CENTRAL SPLNS AND FAR SRN PANHANDLE. DEEP LAYER SHEAR IS CURRENTLY
VERY WEAK...BUT WILL INCREASE THIS EVENING AS THE LLJ CRANKS UP.
INSTABILITY IS ALSO ON THE WEAK TO MODERATE SIDE...HIGHEST
POSITIONED ACROSS THE NORTH. THIS ENVIRONMENT SHOULD SUPPORT THE
THREAT FOR ISOLATED STRONG TO SEVERE WIND GUSTS...WITH THE DEEPER
MOISTURE SUPPORTING STRONGER COLD POOLS AND BETTER RAINFALL
POTENTIAL AS WELL.
WHILE WE SHOULD SEE MOST ACTIVITY WANE IN THE EARLY MORNING
HRS...CONTINUED BROAD UPWARD MOTION IN NW FLOW WILL KEEP A CHANCE OF
SOME ISOLD SHOWERS/TSTMS GOING THROUGH THU MORNING. THEN...A COLD
FRONT IS EXPECTED TO MOVE INTO OUT NRN ZONES LATE THU
MORNING...LIKELY STALLING OUT SOMEWHERE ACROSS THE FAR SRN PANHANDLE
AND NW SPLNS BY MIDDAY OR EARLY AFTERNOON. THIS FRONT SHOULD ABLY SERVE
AS A FOCUS FOR CONVECTIVE INITIATION THURSDAY AFTERNOON. TEMPS MAY
NOT MAKE IT OUT OF THE 80S NORTH OF THE FRONT...WHILE WE EXPECT
HIGHS TO ONCE AGAIN CLIMB INTO THE UPPER 90S TO THE SOUTH OF THE
FRONT. SOUTH OF THE FRONT...THERE WILL BE SOME DOWNBURST POTENTIAL
FROM THE TSTM ACTIVITY....WHILE NORTH OF THE FRONT RAINFALL CHANCES
WILL BE BETTER.
LONG TERM...
THURSDAY NIGHT THRU SATURDAY...
THE COLD FRONT FROM EARLIER IN THE DAY THURSDAY SHOULD BE STALLED
SOMEWHERE IN THE NORTHERN HALF OF THE CWA BY THURSDAY EVENING. A
GENERAL WEAKNESS IN WINDS ALOFT MAY ACT TO KEEP CONVECTION FOCUSED
RELATIVELY CLOSE TO THE BOUNDARY...OR PERHAPS EVEN NORTH OF THE
FRONT AS ISENTROPIC LIFT IS PROGGED TO AMPLIFY OVERNIGHT AS PER THE
GFS. OPTED TO THEREFORE TIGHTEN THE POP GRADIENT THU NIGHT FROM
NORTH-TO-SOUTH TO REFLECT THIS THINKING. BY FRIDAY...ATTENTION WILL
TURN MORE TO THE SUBTROPICAL PLUME OF MOISTURE CURRENTLY HUGGING THE
WRN COAST OF MEXICO. SOME OF THIS MOISTURE WILL SPREAD NORTH BEFORE
CURLING EASTWARD INTO WEST TX WITHIN A REGION OF LOWERED HEIGHTS
BETWEEN TWO 700MB HIGH CENTERS. PROVIDED THE OSCILLATING FRONTAL
BOUNDARY REMAINS IN THE CWA...LIKELY POPS MAY BE WARRANTED FRI AFTN.
HOWEVER...THIS STRATEGY IS CLOUDED WITH DOUBT AS THE NAM NOW
RETREATS THE BOUNDARY WELL NORTH INTO THE PANHANDLE WHILE PUSHING
HIGHS AREA WIDE INTO THE 90S. NOT YET WILLING TO BREAK CONTINUITY AS
THE NAM`S FRONTAL SOLUTION SEEMS TOO AGGRESSIVE...SO WILL SIDE WITH
THE GFS FAVORING A MORE SOUTHERLY BOUNDARY POSITION. A LULL IN PRECIP
CHANCES MAY VERY WELL DEVELOP FRI EVENING BEFORE DEEPER ASCENT
ARRIVES LATE IN THE NIGHT AND EARLY SAT COURTESY OF A CYCLONICALLY
CURVED JET STREAK DIVING THROUGH THE SOUTHERN GREAT PLAINS. ENHANCED
UPPER DIVERGENCE IN THE EXIT REGION OF THIS 2-CELL MAXIMA WOULD TEND
TO FAVOR THE BEST POPS AFTER MIDNIGHT PRIMARILY ACROSS THE NERN 1/3
OF THE CWA BEFORE EXPANDING OVER THE REMAINDER OF THE AREA SAT
MORNING AS THE BASE OF AN UPPER TROUGH IN NWLY FLOW DRAWS CLOSER.
GIVEN THIS PATTERN IN THE PRESENCE OF PWATS AROUND 1.5 INCHES...WE
COULD CERTAINLY RATCHET POPS INTO THE LIKELY REALM...BUT WILL SETTLE
FOR HIGH CHANCE AT THIS TIME AS THIS WINDOW IS STILL FIVE PERIODS
OUT AND SUBJECT TO CHANGE.
GFS AND ECMWF ARE IN A SURPRISINGLY GOOD AGREEMENT...FOR THE MOST PART...
FOR THE PERIODS SAT THRU TUES. BOTH SEEM TO BE IN AN AGREEMENT WITH
A STALLED FRONT DRAPED FROM THE NC COAST TO THE TX PANHANDLE.
DEWPOINTS WILL BE FAIRLY HIGH...AROUND THE LOWER 60S. THIS COUPLED
WITH UPPER LEVEL DIVERGENCE SHOULD ALLOW WITH SOME PRECIP. I HAVE
BUMPED UP THE POPS JUST A BIT FOR SAT EVENING. THE FRONT SHOULD MOVE
OUT OF THE AREA BY SUN MORNING/EARLY AFTERNOON. HIGHS FOR SAT SHOULD
BE IN THE UPPER 80S. BEYOND THEN THE MODELS VARY IN PRECIP CHANCES.
THE GFS KEEPS PRECIP SOMEWHAT SUPPRESSED AND LOCALIZED OVER THE
PANHANDLE WITH THE INFLUENCE OF AN UPPER LEVEL HIGH WHILE THE 12Z
ECMWF HAS MORE WIDESPREAD COVERAGE DUE TO THE INFLUENCE OF A
SHORTWAVE TROF OVER KS. HAVE KEPT POPS ON THE DOWN LOW AT THE
CURRENT TIME DUE TO UNCERTAINTY BUT DO HAVE A MENTION OF THEM.
LATER IN THE PERIOD AROUND WED THE 12Z GFS AND THE 00Z ECMWF
DIFFER...ESPECIALLY NEAR THE SURFACE. THE GFS IS TRYING TO DEVELOP A
1001 MB LOW IN EASTERN MT WITH A SURFACE TROF DRAPED DOWN TO THE OK
PANHANDLE WED MORNING AND DEEPENS IT TO A 997 MB LOW BY THUR
MORNING...WHILE PUSHING A DRYLINE INTO THE WESTERN PANHANDLE. THE
ECMWF HAS A 1022 MB HIGH OVER MT AND SINKS DOWN TO CO BY THUR
MORNING. HOWEVER...THE NEW 12Z ECMWF HAS COME MORE IN LINE WITH THE
12Z GFS EXCEPT WITH ABOUT A 6 HOUR TIMING DELAY. EITHER WAY...UPPER
LEVEL RIDGING APPEARS TO BE THE NAME OF THE GAME OVER WESTERN TEXAS
AND THAT SHOULD HELP SUPPRESS CONVECTION AND KEEP TEMPS AT THE SURFACE
WARM. ALDRICH
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 65 86 63 85 65 / 30 40 40 40 40
TULIA 67 88 65 86 65 / 30 40 40 40 50
PLAINVIEW 68 90 65 86 66 / 30 30 40 40 50
LEVELLAND 68 93 67 88 67 / 30 30 20 40 40
LUBBOCK 70 93 68 88 68 / 30 30 20 40 40
DENVER CITY 69 94 68 88 68 / 20 20 20 30 30
BROWNFIELD 67 94 68 89 68 / 20 20 20 30 40
CHILDRESS 72 97 69 90 69 / 20 30 40 40 50
SPUR 70 96 70 90 71 / 20 20 20 40 50
ASPERMONT 71 100 72 92 71 / 20 20 20 30 50
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
02
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
340 AM EDT THU AUG 16 2012
.SYNOPSIS...
WEAK HIGH PRESSURE BUILDS IN OVERNIGHT ALLOWING FOR DRIER WEATHER
INTO THURSDAY. ANOTHER FRONT IMPACTS THE REGION FRIDAY INTO THE
WEEKEND WITH A BETTER CHANCE FOR SHOWERS AND
THUNDERSTORMS...ESPECIALLY FRIDAY THROUGH SATURDAY ALONG WITH
SEASONABLY MILD TEMPERATURES.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 345 AM EDT THURSDAY...
NO SIGNIFICANT CHANGES AT THIS TIME. DENSE FOG FORMING IN THE RIVER
VALLEYS...OTHERWISE MOSTLY CLEAR AT THIS TIME. ONLY MINOR
MODIFICATIONS TO T/TD GRIDS. POPS ARE NIL AND WILL REMAIN SO FOR THE
NEXT 18 HRS OR SO.
AS OF 1010 PM EDT WEDNESDAY...
LOOKS LIKE THE LAST OF THE SHRA FINALLY FADING ACROSS THE EAST
WITH PERHAPS STILL AN ISOLATED SHRA TO AFFECT LYNCHBURG BEFORE
PRECIP ENDS WITH LOSS OF HEATING/INSTABILITY. HOWEVER SOME LOW
CLOUDS CONTINUE TO LINGER EAST OF THE BLUE RIDGE IN VIRGINIA AND
REMAIN BANKED UP WITH UPSLOPE FLOW AROUND BLUEFIELD SO UPDATING TO
INCLUDE MORE CLOUDS EARLY ON. OTRW ARRIVAL OF VERY DRY AIR ALOFT
PER VAPOR LOOP/EVENING RAOBS IN CONJUNCTION WITH HIGH PRESSURE
BUILDING IN FROM THE WEST SHOULD MAKE FOR MAINLY CLEAR SKIES AND
MORE COMFORTABLE TEMPS AFTER MIDNIGHT AS DRIER AIR SEEPS IN. SOME
FOG AGAIN LIKELY ESPCLY VALLEYS AND WHERE SPOTTY HEAVIER DOWNPOURS
OCCURRED EARLIER SO TWEAKING COVERAGE A LITTLE. BASICALLY LEAVING
TEMPS CLOSE TO PREVIOUS EXCEPT NUDGING UP SLIGHTLY IN THE EAST
WHERE DRIER AIR WILL BE SLOWER TO ARRIVE. OTRW LOWS MAINLY IN THE
COOLER 50S MOUNTAINS TO 60-65 EAST ON TRACK.
AS OF 605 PM EDT WEDNESDAY...
EVENING UPDATE TO LOWER POPS ACROSS THE FAR SOUTH AS DEEPER
CONVECTION ACROSS CENTRAL NC HAS TAKEN BETTER LIFT FARTHER SOUTH.
HOWEVER BUMPED UP COVERAGE A BIT OVER THE NE PER LEFTOVER BAND OF
SHRA/TSRA HEADING DOWN JUST EAST OF THE BLUE RIDGE AND OVER THE NW
JUST AHEAD OF THE ACTUAL DEWPOINT FRONT. APPEARS ENOUGH
INSTABILITY OVER THE NE TO PROMOTE SOME ISOLATED TSRA SO KEPT
MENTION THERE WITH MAINLY SHRA ELSW. THIS BOUNDARY SHOULD PUSH
THRU THE MOUNTAINS OVER THE NEXT FEW HOURS AND THE REST OF THE CWA
THIS EVENING BEHIND THE PASSING UPPER VORT. GOOD SUBSIDENCE BEHIND
THIS FEATURE SHOULD BRING AN END TO ANY REMAINING SHRA WITH LOSS
OF HEATING SO ONLY ISOLATED POPS AT BEST ELSW THIS EVENING.
PREVIOUS DISCUSSION AS OF 325 PM EDT WEDNESDAY...
MAIN SHORTWAVE IS STARTING TO MOVE INTO NRN VA ATTM...WITH PIECES OF
VORT ENERGY OCCURRING ALONG THE BACK EDGE OF THE DEEPER MOISTURE
ACROSS THE SOUTHERN APPALACHIANS INTO SRN WV. STILL APPEARS THE NEAR
TERM MESOSCALE MODELS HOLD CONVECTION THAT IS OCCURRING OVER THE
CENTRAL PORTION OF OUR FORECAST AREA EAST INTO THE PIEDMONT FOR LATE
AFTERNOON. FOLLOWED THE LATEST HRRR EXCEPT SLOWED ITS TIMING DOWN
GIVEN SPEED OF ECHOES ON RADAR BEING SLOWER. ATTM...THINK WILL SEE
THUNDER THREAT PUSHING EAST OF THE BLUE RIDGE SOON....THEN SHOULD
EXPECT SHOWERS TO WIND DOWN AND DISSIPATE AFTER 00Z. SOME CLEARING
AHEAD OF THE VORT LOBE MAY CREATE ENOUGH INSTABILITY THAT A FEW
CELLS COULD BE STRONG TO EVEN SEVERE WITH DAMAGING WINDS POSSIBLE.
CURRENT ANALYSIS SUGGESTS THE GREATEST POTENTIAL FOR THIS WILL BE
SOUTHEAST OF OUR CWA...BUT THOSE AREAS SOUTH OF HIGHWAY 58 FROM
DANVILLE TO SOUTH BOSTON INTO NC MAY BE IN A BETTER ENVIRONMENT FOR
THIS.
AFTER THE ACTIVITY WANES TONIGHT...SKIES SHOULD CLEAR AND SOME FOG
WILL FORM ESPECIALLY WHERE IT RAINED...BUT OVERALL KEPT IT IN THE
MTNS. WILL SEE JUST ENOUGH DRY AIR TO LOWER TEMPS SOME
TONIGHT...CLOSER TO LOCAL MOS WITH MID 50S MTNS TO LOWER 60S
SOUTHEAST.
FLOW WILL BACK AGAIN TO THE SOUTHWEST THU AFTERNOON WITH RISING
HEIGHTS. HIGHS WILL BE WARM ESPECIALLY EAST WITH NEAR 90...WHILE THE
MTNS STAY IN THE LOWER 80S.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 350 PM WEDNESDAY...
UPPER AIR PATTERN BECOMES AMPLIFIED FOR THE WEEKS END WITH RIDGE
OVER THE ROCKIES AND TROUGH IN THE EAST. DEEPER TROUGHING IN THE
EAST WILL BE PRECEDED BY WEAK RIDGING THURSDAY NIGHT AND EARLY
FRIDAY AHEAD OF SURFACE COLD FRONT THAT WILL BE MOVING THROUGH THE
OHIO VALLEY. WITH 85H TEMPS +18 DEG C...SHOULD SEE SPIKE IN
TEMPERATURE PRIOR TO FROPA FRIDAY EVENING. CLOUD INCREASE AHEAD OF
FRONT SHOULD KEEP TEMPS IN THE MTNS IN THE 70S...BUT NEAR FULL
INSOLATION EAST OF MTNS WILL LIKELY PERMIT TEMPS TO TEST 90 EAST
OF THE BLUE RIDGE. HIGHEST POPS FRIDAY ANTICIPATED IN THE
MTNS...SHRA/TSRA DEVELOPING IN ADV OF FRONT AND MOVING ACROSS THE
CWA DURING THE LATE AFTERNOON AND EVENING.
MODELS SLOW PROGRESSION OF FRONT AS IT CROSSES THE CWA...THUS CLOUDS
AND PRECIP THREAT MAY LINGER INTO SATURDAY. NOT OVERLY EXCITED
ABOUT INSTABILITY SATURDAY PER LINGERING CLOUD COVER...THUS THINK
ANY PRECIP SATURDAY WOULD BE IN THE FORM OF SHOWERS AND LITTLE OR NO
THUNDER. FRONT IS FCST TO DISSIPATE OVER OR JUST SOUTH OF THE AREA
SATURDAY NIGHT...AMOUNT OF CLEARING DEPENDENT ON FRONTAL REMNANTS.
TEMPERATURES SATURDAY WILL BE TEMPERED BY CLOUD COVER...L-M 70S
MTS...LOWER 80S PIEDMONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 350 PM WEDNESDAY...
UPPER LEVEL TROUGH SETS UP SHOP OVER THE ERN CONUS FOR NEXT WEEK.
FLOW ALOFT REMAINS CYCLONIC WITH EMBEDDED SHORT WAVE ENERGY HELPING
TO KEEP THE FLOW AMPLIFIED. PRESENCE OF THE TROUGH SUGGESTS TEMPS
WILL RUN BLO MEDIAN. AS FOR PRECIP...A LOT WILL DEPEND ON THE
AMOUNT OF RETURN FLOW THAT CAN DEVELOP AND TIMING OF ANY SHORT WAVE
ENERGY. FOR NOW WILL FOCUS HIGHEST POPS VCNTY OF MTNS WHERE LOW
LEVEL CONVERGENCE WILL BE GREATEST...ALTHOUGH COOLER THAN NORMAL
TEMPS SUGGESTS INSTABILITY WILL BE MAINLY DIURNALLY DRIVEN.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 150 AM EDT THURSDAY...
FORECAST AREA CURRENTLY IN BETWEEN WEATHER SYSTEMS...WITH THE SHORT
WAVE OF WEDNESDAY HAVING PASSED OFF TO THE EAST AND ANOTHER STRONGER
UPPER LOW PRESSURE SYSTEM APPROACHING FROM THE WEST FOR FRI INTO THE
WEEKEND. PRIOR TO 14Z...THERE WILL BE POCKETS OF IFR-LIFR
VSBYS/CIGS...MAINLY IN THE USUALLY FAVORED SPOTS FOR SUCH...NAMELY
LWB...BLF...AND BCB. WILL NEED TO WATCH LYH FOR SUCH LATER AS WELL.
CALM WINDS AND MOIST GROUND FROM WIDESPREAD -RA WED WILL PROMOTE
RADIATIONAL FOG DEVELOPMENT OVERNIGHT. ALREADY OBSERVING IFR-LIFR
VSBYS/CIGS AT BLF. AFT 14Z...EXPECT VFR CIGS/VSBYS THROUGHOUT
REMAINDER OF TAF VALID PERIOD WITH ONLY A FEW FAIR WEATHER CU
EXPECTED AOA 050. WINDS CHAOTIC AND LIGHT THROUGHOUT TAF VALID
PERIOD...FAVORING A LIGHT WNW DIRECTION THROUGH MID-DAY...THEN
MOSTLY VRB03-04KT FOR THE REMAINDER OF TAF VALID PERIOD.
AS OF 650 PM EDT WEDNESDAY...
FEW SHOWERS REMAIN ACROSS THE NE BUT EXPECT FURTHER DISSIPATION WITH
LOSS OF HEATING SO THINKING MAY BE ABLE TO RUN WITHOUT ANY PRECIP
MENTION TO INIT AT MOST TAF SITES OUTSIDE OF KLYH THIS EVENING.
WAVE EXITS BY MIDNIGHT WITH DECENT SUBSIDENCE SPILLING EAST
ALLOWING FOR CLEARING SKIES AND SLOWLY FALLING DEWPOINTS. HOWEVER
APPEARS ENOUGH LOW LEVEL MOISTURE MAY LINGER LONG ENOUGH TO CAUSE
FOG FORMATION IN THE VALLEYS AND IN SPOTS NEAR WHERE EARLIER RAIN
OCCURRED ESPCLY KDAN. LOW CIGS MAY ALSO BANK UP AROUND KBLF
OVERNIGHT GIVEN WEAK NW FLOW WITH MVFR/IFR FOG LIKELY. OTRW
THINKING LIFR IN FOG/STRATUS AT KLWB AND MAINLY MVFR KBCB/KDAN AND
PERHAPS KLYH.
ANY FOG AND/OR LOW CLOUDS SHOULD HAVE ERODED BY MID MORNING
THURSDAY WITH HIGH PRESSURE PROVIDING FOR VFR UNDER FEW/SCTD CU
INTO THE AFTERNOON UNDER LIGHT WINDS.
ASIDE FROM SOME LATE NIGHT FOG AT LWB/BCB ANTICIPATE THE NEXT
THREAT FOR SUB VFR TO COME WITH A FRONT FRIDAY INTO SATURDAY. THE
FRONT SLOWS AND LINGERS ACROSS THE CAROLINAS THROUGH THE WEEKEND
SUCH THAT THE THREAT OF SHOWERS MAY OCCUR ACROSS SOUTHERN
SECTIONS...WITH SOME MVFR POSSIBLE. THE FRONT WILL BE MOVING SLOWLY
EAST BY MONDAY AS HIGH PRESSURE WORKS IN FROM THE OHIO VALLEY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...RAB/JH/WP
SHORT TERM...PM
LONG TERM...PM
AVIATION...RAB/JH/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
150 AM EDT THU AUG 16 2012
.SYNOPSIS...
WEAK HIGH PRESSURE BUILDS IN OVERNIGHT ALLOWING FOR DRIER WEATHER
INTO THURSDAY. ANOTHER FRONT IMPACTS THE REGION FRIDAY INTO THE
WEEKEND WITH A BETTER CHANCE FOR SHOWERS AND
THUNDERSTORMS...ESPECIALLY FRIDAY THROUGH SATURDAY ALONG WITH
SEASONABLY MILD TEMPERATURES.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 1010 PM EDT WEDNESDAY...
LOOKS LIKE THE LAST OF THE SHRA FINALLY FADING ACROSS THE EAST
WITH PERHAPS STILL AN ISOLATED SHRA TO AFFECT LYNCHBURG BEFORE
PRECIP ENDS WITH LOSS OF HEATING/INSTABILITY. HOWEVER SOME LOW
CLOUDS CONTINUE TO LINGER EAST OF THE BLUE RIDGE IN VIRGINIA AND
REMAIN BANKED UP WITH UPSLOPE FLOW AROUND BLUEFIELD SO UPDATING TO
INCLUDE MORE CLOUDS EARLY ON. OTRW ARRIVAL OF VERY DRY AIR ALOFT
PER VAPOR LOOP/EVENING RAOBS IN CONJUNCTION WITH HIGH PRESSURE
BUILDING IN FROM THE WEST SHOULD MAKE FOR MAINLY CLEAR SKIES AND
MORE COMFORTABLE TEMPS AFTER MIDNIGHT AS DRIER AIR SEEPS IN. SOME
FOG AGAIN LIKELY ESPCLY VALLEYS AND WHERE SPOTTY HEAVIER DOWNPOURS
OCCURRED EARLIER SO TWEAKING COVERAGE A LITTLE. BASICALLY LEAVING
TEMPS CLOSE TO PREVIOUS EXCEPT NUDGING UP SLIGHTLY IN THE EAST
WHERE DRIER AIR WILL BE SLOWER TO ARRIVE. OTRW LOWS MAINLY IN THE
COOLER 50S MOUNTAINS TO 60-65 EAST ON TRACK.
AS OF 605 PM EDT WEDNESDAY...
EVENING UPDATE TO LOWER POPS ACROSS THE FAR SOUTH AS DEEPER
CONVECTION ACROSS CENTRAL NC HAS TAKEN BETTER LIFT FARTHER SOUTH.
HOWEVER BUMPED UP COVERAGE A BIT OVER THE NE PER LEFTOVER BAND OF
SHRA/TSRA HEADING DOWN JUST EAST OF THE BLUE RIDGE AND OVER THE NW
JUST AHEAD OF THE ACTUAL DEWPOINT FRONT. APPEARS ENOUGH
INSTABILITY OVER THE NE TO PROMOTE SOME ISOLATED TSRA SO KEPT
MENTION THERE WITH MAINLY SHRA ELSW. THIS BOUNDARY SHOULD PUSH
THRU THE MOUNTAINS OVER THE NEXT FEW HOURS AND THE REST OF THE CWA
THIS EVENING BEHIND THE PASSING UPPER VORT. GOOD SUBSIDENCE BEHIND
THIS FEATURE SHOULD BRING AN END TO ANY REMAINING SHRA WITH LOSS
OF HEATING SO ONLY ISOLATED POPS AT BEST ELSW THIS EVENING.
PREVIOUS DISCUSSION AS OF 325 PM EDT WEDNESDAY...
MAIN SHORTWAVE IS STARTING TO MOVE INTO NRN VA ATTM...WITH PIECES OF
VORT ENERGY OCCURRING ALONG THE BACK EDGE OF THE DEEPER MOISTURE
ACROSS THE SOUTHERN APPALACHIANS INTO SRN WV. STILL APPEARS THE NEAR
TERM MESOSCALE MODELS HOLD CONVECTION THAT IS OCCURRING OVER THE
CENTRAL PORTION OF OUR FORECAST AREA EAST INTO THE PIEDMONT FOR LATE
AFTERNOON. FOLLOWED THE LATEST HRRR EXCEPT SLOWED ITS TIMING DOWN
GIVEN SPEED OF ECHOES ON RADAR BEING SLOWER. ATTM...THINK WILL SEE
THUNDER THREAT PUSHING EAST OF THE BLUE RIDGE SOON....THEN SHOULD
EXPECT SHOWERS TO WIND DOWN AND DISSIPATE AFTER 00Z. SOME CLEARING
AHEAD OF THE VORT LOBE MAY CREATE ENOUGH INSTABILITY THAT A FEW
CELLS COULD BE STRONG TO EVEN SEVERE WITH DAMAGING WINDS POSSIBLE.
CURRENT ANALYSIS SUGGESTS THE GREATEST POTENTIAL FOR THIS WILL BE
SOUTHEAST OF OUR CWA...BUT THOSE AREAS SOUTH OF HIGHWAY 58 FROM
DANVILLE TO SOUTH BOSTON INTO NC MAY BE IN A BETTER ENVIRONMENT FOR
THIS.
AFTER THE ACTIVITY WANES TONIGHT...SKIES SHOULD CLEAR AND SOME FOG
WILL FORM ESPECIALLY WHERE IT RAINED...BUT OVERALL KEPT IT IN THE
MTNS. WILL SEE JUST ENOUGH DRY AIR TO LOWER TEMPS SOME
TONIGHT...CLOSER TO LOCAL MOS WITH MID 50S MTNS TO LOWER 60S
SOUTHEAST.
FLOW WILL BACK AGAIN TO THE SOUTHWEST THU AFTERNOON WITH RISING
HEIGHTS. HIGHS WILL BE WARM ESPECIALLY EAST WITH NEAR 90...WHILE THE
MTNS STAY IN THE LOWER 80S.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 350 PM WEDNESDAY...
UPPER AIR PATTERN BECOMES AMPLIFIED FOR THE WEEKS END WITH RIDGE
OVER THE ROCKIES AND TROUGH IN THE EAST. DEEPER TROUGHING IN THE
EAST WILL BE PRECEDED BY WEAK RIDGING THURSDAY NIGHT AND EARLY
FRIDAY AHEAD OF SURFACE COLD FRONT THAT WILL BE MOVING THROUGH THE
OHIO VALLEY. WITH 85H TEMPS +18 DEG C...SHOULD SEE SPIKE IN
TEMPERATURE PRIOR TO FROPA FRIDAY EVENING. CLOUD INCREASE AHEAD OF
FRONT SHOULD KEEP TEMPS IN THE MTNS IN THE 70S...BUT NEAR FULL
INSOLATION EAST OF MTNS WILL LIKELY PERMIT TEMPS TO TEST 90 EAST
OF THE BLUE RIDGE. HIGHEST POPS FRIDAY ANTICIPATED IN THE
MTNS...SHRA/TSRA DEVELOPING IN ADV OF FRONT AND MOVING ACROSS THE
CWA DURING THE LATE AFTERNOON AND EVENING.
MODELS SLOW PROGRESSION OF FRONT AS IT CROSSES THE CWA...THUS CLOUDS
AND PRECIP THREAT MAY LINGER INTO SATURDAY. NOT OVERLY EXCITED
ABOUT INSTABILITY SATURDAY PER LINGERING CLOUD COVER...THUS THINK
ANY PRECIP SATURDAY WOULD BE IN THE FORM OF SHOWERS AND LITTLE OR NO
THUNDER. FRONT IS FCST TO DISSIPATE OVER OR JUST SOUTH OF THE AREA
SATURDAY NIGHT...AMOUNT OF CLEARING DEPENDENT ON FRONTAL REMNANTS.
TEMPERATURES SATURDAY WILL BE TEMPERED BY CLOUD COVER...L-M 70S
MTS...LOWER 80S PIEDMONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 350 PM WEDNESDAY...
UPPER LEVEL TROUGH SETS UP SHOP OVER THE ERN CONUS FOR NEXT WEEK.
FLOW ALOFT REMAINS CYCLONIC WITH EMBEDDED SHORT WAVE ENERGY HELPING
TO KEEP THE FLOW AMPLIFIED. PRESENCE OF THE TROUGH SUGGESTS TEMPS
WILL RUN BLO MEDIAN. AS FOR PRECIP...A LOT WILL DEPEND ON THE
AMOUNT OF RETURN FLOW THAT CAN DEVELOP AND TIMING OF ANY SHORT WAVE
ENERGY. FOR NOW WILL FOCUS HIGHEST POPS VCNTY OF MTNS WHERE LOW
LEVEL CONVERGENCE WILL BE GREATEST...ALTHOUGH COOLER THAN NORMAL
TEMPS SUGGESTS INSTABILITY WILL BE MAINLY DIURNALLY DRIVEN.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 150 AM EDT THURSDAY...
FORECAST AREA CURRENTLY IN BETWEEN WEATHER SYSTEMS...WITH THE SHORT
WAVE OF WEDNESDAY HAVING PASSED OFF TO THE EAST AND ANOTHER STRONGER
UPPER LOW PRESSURE SYSTEM APPROACHING FROM THE WEST FOR FRI INTO THE
WEEKEND. PRIOR TO 14Z...THERE WILL BE POCKETS OF IFR-LIFR
VSBYS/CIGS...MAINLY IN THE USUALLY FAVORED SPOTS FOR SUCH...NAMELY
LWB...BLF...AND BCB. WILL NEED TO WATCH LYH FOR SUCH LATER AS WELL.
CALM WINDS AND MOIST GROUND FROM WIDESPREAD -RA WED WILL PROMOTE
RADIATIONAL FOG DEVELOPMENT OVERNIGHT. ALREADY OBSERVING IFR-LIFR
VSBYS/CIGS AT BLF. AFT 14Z...EXPECT VFR CIGS/VSBYS THROUGHOUT
REMAINDER OF TAF VALID PERIOD WITH ONLY A FEW FAIR WEATHER CU
EXPECTED AOA 050. WINDS CHAOTIC AND LIGHT THROUGHOUT TAF VALID
PERIOD...FAVORING A LIGHT WNW DIRECTION THROUGH MID-DAY...THEN
MOSTLY VRB03-04KT FOR THE REMAINDER OF TAF VALID PERIOD.
AS OF 650 PM EDT WEDNESDAY...
FEW SHOWERS REMAIN ACROSS THE NE BUT EXPECT FURTHER DISSIPATION WITH
LOSS OF HEATING SO THINKING MAY BE ABLE TO RUN WITHOUT ANY PRECIP
MENTION TO INIT AT MOST TAF SITES OUTSIDE OF KLYH THIS EVENING.
WAVE EXITS BY MIDNIGHT WITH DECENT SUBSIDENCE SPILLING EAST
ALLOWING FOR CLEARING SKIES AND SLOWLY FALLING DEWPOINTS. HOWEVER
APPEARS ENOUGH LOW LEVEL MOISTURE MAY LINGER LONG ENOUGH TO CAUSE
FOG FORMATION IN THE VALLEYS AND IN SPOTS NEAR WHERE EARLIER RAIN
OCCURRED ESPCLY KDAN. LOW CIGS MAY ALSO BANK UP AROUND KBLF
OVERNIGHT GIVEN WEAK NW FLOW WITH MVFR/IFR FOG LIKELY. OTRW
THINKING LIFR IN FOG/STRATUS AT KLWB AND MAINLY MVFR KBCB/KDAN AND
PERHAPS KLYH.
ANY FOG AND/OR LOW CLOUDS SHOULD HAVE ERODED BY MID MORNING
THURSDAY WITH HIGH PRESSURE PROVIDING FOR VFR UNDER FEW/SCTD CU
INTO THE AFTERNOON UNDER LIGHT WINDS.
ASIDE FROM SOME LATE NIGHT FOG AT LWB/BCB ANTICIPATE THE NEXT
THREAT FOR SUB VFR TO COME WITH A FRONT FRIDAY INTO SATURDAY. THE
FRONT SLOWS AND LINGERS ACROSS THE CAROLINAS THROUGH THE WEEKEND
SUCH THAT THE THREAT OF SHOWERS MAY OCCUR ACROSS SOUTHERN
SECTIONS...WITH SOME MVFR POSSIBLE. THE FRONT WILL BE MOVING SLOWLY
EAST BY MONDAY AS HIGH PRESSURE WORKS IN FROM THE OHIO VALLEY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...JH/WP
SHORT TERM...PM
LONG TERM...PM
AVIATION...RAB/JH/WP
AREA FORECAST DISCUSSION
NWS ALBANY NY
1030 AM EDT THU AUG 16 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN FROM PENNSYLVANIA THIS
AFTERNOON WITH A BRIEF PERIOD OF FAIR AND DRY WEATHER. A COLD FRONT
WILL MOVE THROUGH FRIDAY AFTERNOON...TRIGGERING MORE SHOWERS AND
THUNDERSTORMS...AND WILL BE FOLLOWED BY FAIR AND COOLER CONDITIONS
FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1030 AM EDT...SFC HIGH PRESSURE CONTINUES TO RIDGE IN FROM
W-CNTRL PA. THE RUC SHOWS A MID-LEVEL RIDGE AXIS BUILDING IN FROM
LAKE HURON AND MICHIGAN. AN UPPER-LEVEL IMPULSE IS FEEDING INTO
THE SFC WAVE NEAR MAINE. THE WATER VAPOR LOOP CONTINUES TO SHOW
LOTS OF MID AND UPPER LEVEL DRY AIR FILTER IN ALOFT. THE CUMULUS
FIELD IS NOT THAT IMPRESSIVE IN THE LATE MORNING. WE REMOVED ALL
THE POPS FOR THE LATE MORNING AND AFTERNOON. THERE MAY BE SOME
INSTABILITY CUMULUS OVER SRN GREENS..BERKS...TACONICS...AND
LITCHFIELD HILLS...BUT THE LATEST 12Z RAOB SHOWS A PAIR OF MID AND
UPPER LEVEL INVERSIONS WHICH SHOULD LIMIT ANY DEEP COLD POOL
RELATED CONVECTIVE GROWTH.
PARTLY TO MOSTLY SUNNY CONDITIONS WILL PREVAIL WITH MANAGEABLE
HUMIDITY LEVELS. STUCK WITH CURRENT MAX TEMPS FOR NOW...WITH
LOWER/MID 80S IN VALLEY REGIONS...AND 75-80 ACROSS HIGHER
ELEVATIONS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
TONIGHT...MAINLY CLEAR SKIES ARE EXPECTED FOR MUCH OF THE
NIGHT...BEFORE SOME MID LEVEL CLOUDS APPROACH FROM THE WEST. THERE
IS A POSSIBILITY THAT SOME SHOWERS OR THUNDERSTORMS REACH FAR NW
AREAS TOWARD DAYBREAK...AS A LOW LEVEL JET WITHIN INCREASING WARM
ADVECTION TRANSLATES TOWARD THIS REGION. ELSEWHERE...HAVE KEPT
CONDITIONS RAIN-FREE.
FRIDAY...A COLD FRONT WILL APPROACH FROM THE WEST DURING THE MID
TO LATE AFTERNOON HOURS. SCATTERED SHOWERS AND THUNDERSTORMS WILL
LIKELY DEVELOP WITHIN A NARROW BAND NEAR OR JUST AHEAD OF THE
FRONT...DEVELOPING ACROSS WESTERN AREAS BY LATE MORNING...THEN
SPREADING INTO THE CAPITAL REGION BY MIDDAY/EARLY AFTERNOON...AND
AREAS TO THE S/E BY LATE AFTERNOON. ABUNDANT HIGH AND MID LEVEL
CLOUDS ARE EXPECTED TO ENVELOPE THE REGION BY LATE MORNING...WHICH
MAY TEND TO LIMIT POTENTIAL DESTABILIZATION AND THUNDERSTORM
INTENSITY...DESPITE INCREASING 0-6 KM VERTICAL SHEAR OF 30-40 KT
BY LATE AFTERNOON. SHOULD MORE SUNSHINE OCCUR...THEN THE GREATER
DESTABILIZATION COULD LEAD TO STRONG TO SEVERE
THUNDERSTORMS...WITH STRONG WINDS AND HAIL POSSIBLE. THE STORM
PREDICTION CENTER INDICATES THAT A CATEGORICAL SLIGHT RISK MAY BE
WARRANTED DEPENDING ON HOW MUCH DESTABILIZATION CAN OCCUR.
OTHERWISE...EXPECT MAX TEMPS TO REACH THE LOWER/MID 80S IN
VALLEYS...AND 70S ACROSS HIGHER ELEVATIONS ACROSS NORTHERN AREAS.
FRI NT...THE COLD FRONT WILL BE SLOWING ITS SE PROGRESSION...AS
THE RIGHT ENTRANCE REGION OF A JET MAX ACROSS THE EASTERN GREAT
LAKES APPROACHES. THIS MAY TEND TO KEEP SHOWERS/THUNDERSTORMS
LINGERING WELL INTO THE NIGHT ACROSS THE MID HUDSON VALLEY REGION
AND NW CT...POSSIBLY INTO THE BERKSHIRES...WHERE CHC POPS ARE
RETAINED THROUGH THE NIGHT. ELSEWHERE...OTHER THAN POSSIBLE
EVENING SHOWERS...HAVE TRENDED TOWARD DRY CONDITIONS LATER AT
NIGHT...ALONG WITH SOME CLEARING. HAVE SIDED WITH BLEND OF MAV/MET
MOS FOR MIN TEMPS.
SAT-SAT NT...HAVE KEPT SOME SLIGHT CHC POPS ACROSS FAR SE AREAS
FOR SAT MORNING...OTHERWISE EXPECT GENERALLY DRY AND LESS HUMID
CONDITIONS. MAX TEMPS SHOULD REACH 75-80 IN VALLEYS...AND 60S TO
LOWER 70S ACROSS HIGHER ELEVATIONS. FOR SAT NT...IT SHOULD BE
QUITE COOL ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS...AND
HIGHER ELEVATIONS IN SOUTHERN VT...WHERE SOME MIN TEMPS MAY FALL
INTO THE UPPER 30S TO MID 40S. ELSEWHERE...EXPECT MINS TO FALL
INTO THE 50S.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
EXPECT GENERALLY DRY WEATHER FOR MUCH OF THE LONG TERM PERIOD EXCEPT
FOR EARLY IN THE WEEK AS WAVES OF LOW PRESSURE WORK NORTHWARD ALONG A
STATIONARY FRONT ANCHORED ALONG EASTERN SEABOARD. THE BIGGEST IMPACT
WILL BE ACROSS SOUTHERN AND EASTERN ZONES CLOSEST TO THE FRONTAL
BOUNDARY WHERE HIGHEST CHANCE POPS HAVE BEEN PLACED IN THE FORECAST
GRIDS. FROM TUESDAY INTO WEDNESDAY HIGH PRESSURE BUILDS OVER THE
NORTHEAST AS FRONTAL BOUNDARY SLIDES WELL TO THE SOUTH AND EAST.
ON SUNDAY HAVE SLIGHT CHANCE TO LOW CHANCE POPS IN THE GRIDS WITH
HIGHEST POPS FROM THE EASTERN CATSKILLS SOUTHEAST TO THE LITCHFIELD
HILLS DURING THE AFTERNOON WITH SLIGHT CHANCE POPS ON SUNDAY NIGHT.
EXPECT HIGHS ON SUNDAY MAINLY IN THE UPPER 60S TO UPPER 70S WITH A
FEW READINGS AROUND 80 IN THE MID HUDSON VALLEY. LOWS SUNDAY NIGHT
ARE EXPECTED TO BE IN THE UPPER 40S TO UPPER 50S.
FOR MONDAY...A VORT MAX SWINGING AROUND THE UPPER TROUGH WILL RESULT
IN SCATTERED SHOWERS AND POSSIBLY EVEN AN ISOLD THUNDERSTORM. THE
INSTABILITY LOOKS LIMITED AT THIS TIME. HIGHS ARE EXPECTED TO BE IN
THE MID 60S TO UPPER 70S.
MON NIGHT THROUGH WEDNESDAY...HIGH PRESSURE AT THE SFC CONTINUES TO
BUILD IN FROM THE SOUTH AND WEST WITH FAIR AND DRY WEATHER...AND
COMFORTABLE HUMIDITY LEVELS. HIGHS TUESDAY AND WEDNESDAY GENERALLY
UPPER 60S TO UPPER 70S WITH LOWS MONDAY NIGHT AND TUESDAY NIGHT IN
THE 50S.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
EXPECT MAINLY VFR CONDITIONS AT THE TAF SITES THROUGH THE END OF THE
TAF PERIOD AT 12Z FRIDAY. THE EXCEPTION WILL BE SOME LATE NIGHT FOG
TONIGHT AFTER 08Z AT KGFL AND KPSF WHERE BRIEF IFR CONDITIONS
EXPECTED. THERE MAY ALSO BE SOME SHOWERS DEVELOPING MAINLY EAST OF
THE HUDSON RIVER AS UPPER TROUGH SWINGS THROUGH THIS REGION. WL
PLACE VCSH IN THE TAF FOR KPSF UP UNTIL 18Z. EXPECT GENERALLY
SCT045-070 THROUGH ERLY THIS EVENING AND THEN SKC CONDITIONS AFT 00Z
WITH THE AFOREMENTIONED FOG EXPECTED AT KGFL AND KPSF AFT 08Z.
LIGHT AND VARIABLE WINDS WILL BECOME NORTHWEST THIS MORNING AT 3-7
KTS AND THEN LIGHT AND VARIABLE AGAIN THIS EVENING.
OUTLOOK...
FRI...VFR. CHC PM SUB-VFR SHRA/TSRA.
SAT-SUN...VFR...NO SIG WX.
MONDAY...VFR. CHC SUB-VFR -SHRA.
&&
.FIRE WEATHER...
HIGH PRESSURE WILL BUILD IN FROM PENNSYLVANIA THIS
AFTERNOON WITH A BRIEF PERIOD OF FAIR AND DRY WEATHER. A COLD FRONT
WILL MOVE THROUGH FRIDAY AFTERNOON...TRIGGERING MORE SHOWERS AND
THUNDERSTORMS...AND WILL BE FOLLOWED BY FAIR AND COOLER CONDITIONS
FOR THE WEEKEND.
THE RH WILL FALL TO 40-50 PERCENT THIS AFTERNOON...THEN RECOVER TO
90-100 PERCENT TONIGHT...WITH DEW FORMATION LIKELY. THE RH WILL
THEN FALL TO 45-60 PERCENT FRI AFTERNOON.
WINDS WILL BECOME WEST TO NORTHWEST AT 5-15 MPH THIS
AFTERNOON...THEN TREND TOWARD CALM TONIGHT. WINDS WILL BECOME
SOUTH TO SOUTHWEST FRIDAY AT 10-20 MPH. WINDS WILL BE
STRONGER...AND VARIABLE IN DIRECTION IN AND NEAR ANY THUNDERSTORMS
TODAY AND FRIDAY.
&&
.HYDROLOGY...
ISOLATED SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE THROUGH
EARLY THIS AFTERNOON...ESPECIALLY FROM THE HUDSON RIVER VALLEY
EASTWARD. LOCALLY HEAVY...SLOW MOVING DOWNPOURS WILL BE
POSSIBLE...WHICH COULD RESULT IN PONDING OF WATER IN LOW
LYING...POOR DRAINAGE AND URBAN AREAS.
A COLD FRONT WILL BRING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
FOR FRIDAY AFTERNOON AND EVENING. AREAL BASIN AVERAGE AMOUNTS
SHOULD GENERALLY REMAIN UNDER ONE QUARTER OF AN INCH.
HOWEVER...LOCALIZED HEAVIER DOWNPOURS COULD RESULT IN PONDING OF
WATER ONCE AGAIN IN LOW LYING...POOR DRAINAGE AND URBAN AREAS.
DRY CONDITIONS ARE EXPECTED OVER THE WEEKEND.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...KL/WASULA
NEAR TERM...KL/WASULA
SHORT TERM...KL
LONG TERM...11
AVIATION...11
FIRE WEATHER...KL
HYDROLOGY...KL
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1014 AM EDT THU AUG 16 2012
.DISCUSSION...
ATLC RIDGE AXIS EXTENDING FROM THE NRN BAHAMAS INTO THE E GOMEX WILL
INTERACT WITH A FRONTAL TROF OVER THE ERN CONUS TO MAINTAIN A DEEP
BUT LIGHT WRLY FLOW ACRS CENTRAL FL...LATEST RAP ANALYSIS SHOWS BOTH
H100-H70 AND H85-H50 WINDS AOB 10KTS ACRS CENTRAL FL. THIS WILL
ALLOW BOTH SEA BREEZES TO FROM BY EARLY AFTN...BUT WILL NOT PROMOTE
RAPID INLAND MOVEMENT ON EITHER SIDE OF THE PENINSULA.
MORNING SOUNDINGS SHOW PWAT VALUES HAVE INCREASED OVER THE PAST
24HRS...NOW ARND 2.0" ACRS THE PENINSULA...MOISTURE PROFILE IS VERY
SIMILAR WITH MUCH OF THE MOISTURE BLO H70 AND GRADUAL DRYING ABV
H70. SFC DEWPOINTS IN THE M70S AREAWIDE WILL MAKE FOR ANOTHER SULTRY
DAY ACRS THE AREA. MID LVL CAPS ARE ABSENT...ONLY THE SHALLOW
NOCTURNAL SFC INVERSIONS WERE NOTED AND THOSE HAVE BURNED OFF BY
NOW. H85-H70 LAPSE RATES BTWN 6.0-7.0C/KM ARE RESPECTABLE...BUT THE
H85-H50 VALUES BLO 6.0C/DM ARE NOT. DEEP LYR VORT FIELDS REMAIN
QUITE WEAK WHILE UPR LVL DIV FIELDS ARE NEUTRAL OR WEAKLY
CONVERGENT.
SIMILAR WX PATTERN TO YESTERDAY. THE DEEP LYR MOISTURE PROFILE WILL
ALLOW SCT SHRAS/TSRAS TO DVLP AREAWIDE. HOWEVER...WEAK MID/UPR LVL
DYNAMIC SUPPORT WILL TEND TO SUPPRESS DIURNAL CONVECTION OUTSIDE OF
THE IMMEDIATE VICINITY OF THE SEABREEZE/LAKE BREEZE BOUNDARIES.
COVERAGE WILL INCREASE THRU LATE AFTN/EARLY EVNG AS SFC TEMPS WARM
INTO THE L/M90S AND THE SEA BREEZES INTERACT WITH OTHER MESOSCALE
BOUNDARIES. DRIER AIR ALOFT WILL INCREASE THE POTENTIAL FOR STRONG
DOWNBURSTS.
WILL UPDATE FCST TO MENTION EARLIER FORMATION OF TSRAS ALONG THE SEA
BREEZE ON THE EAST SIDE OF LAKE OKEECHOBEE...NO OTHER CHANGES
NECESSARY.
&&
.AVIATION...
THRU 16/17Z...VFR ALL SITES...SFC WNDSHFT FM W/SW TO E/NE AOB 12KTS
CSTL SITES ASSOCD WITH THE EAST COAST SEA BREEZE...ISOLD MVFR SHRAS
S OF KVRB. BTWN 16/17Z-16/20Z...SFC WNDSHFT FM W/SW TO S/SE INTERIOR
SITES AS THE SEA BREEZE STALLS W OF I-95...SCT MVFR SHRAS/ISOLD
TSRAS S OF KVRB AND W OF KLEE-KOBE MVG E/NE 5-10KTS. BTWN
16/20Z-16/24Z...SCT IFR/ISOLD LIFR TSRAS N OF KOBE-KVRB AS THE E/W
COAST SEA BREEZES INTERACT. BTWN 17/00Z-17/03Z...SCT MVFR
SHRAS/ISOLD TSRAS N OF KISM-KTIX...VFR ELSEWHERE. AFT 17/03Z...VFR
ALL SITES.
&&
.MARINE...
NO HIGHLIGHTS...NO SIG CHANGES. BROAD RIDGE AXIS OVER S FL WILL
MAINTAIN A WEAK SFC PGRAD AREAWIDE. GENTLE TO MODERATE SFC/BNDRY LYR
WINDS WILL SHIFT FROM W/SW TO E/NE NEAR THE COAST THRU EARLY AFTN AS
THE EAST COAST SEA BREEZE DVLPS AND DRIFTS INLAND. SEAS AOB 2FT
NEARSHORE AND 2-3FT OFFSHORE. SCT TSRAS MOVING OFFSHORE LATE
AFTN/EARLY EVNG...MORE NUMEROUS N OF PORT CANAVERAL.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECAST/AVIATION...BRAGAW
RADAR/IMPACT WX.....LASCODY
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
758 AM EDT THU AUG 16 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 559 AM EDT THU AUG 16 2012
MAIN FCST PROBLEMS FOCUS ON COVERAGE OF SHRA/TSRA ALONG COLD FRONT
AS IT MOVES THROUGH CENTRAL/ERN UPR MI THIS MORNING INTO EARLY
AFTERNOON...POSSIBILITY OF LINGERING INSTABILITY SHRA AND LAKE
EFFECT SHRA IN WAKE OF FRONT THIS AFTERNOON INTO EARLY FRIDAY...AND
GOOD POTENTIAL FOR ADVISORY W-NW WINDS OVER THE KEWEENAW PENINSULA
THIS AFTERNOON INTO THIS EVENING AND THEN OVER SHORELINE AREAS OF
ALGER AND LUCE COUNTIES TONIGHT.
WV IMAGERY AND RUC ANALYSIS SHOWS WELL-DEFINED VIGOROUS NEG-TILT
SHORTWAVE TROUGH MOVING THROUGH NRN ONTARIO. AT THE SFC...A COLD
FRONT EXTENDS SOUTH FROM THIS SYSTEM THROUGH WRN UPR MI AND NW WI.
MOISTURE CONVERGENCE AND INSTABILITY ALONG THIS FRONT HAVE SUPPORTED
SCT SHRA/TSRA ALONG THIS FRONT OVER WRN UPR MI AND NOW OVR FAR
SCNTRL UPR MI IN THE PAST HR.
TODAY AND TONIGHT...SHOWERS AND ISOLD TSRA OVER NCNTRL UPR MI HAVE
DISSIPATED OR MOVED NORTH OVER LAKE SUPERIOR IN PAST HR AS
INSTABILITY HAS WEAKENED ALONG/AHEAD OF COLD FRONT. DYNAMICS WITH
ONTARIO SHORTWAVE WILL SUSTAIN SHOWERS OVER ERN LAKE SUPERIOR THIS
MORNING INTO EARLY AFTERNOON. RUC HAS FCST MLCAPES INCREASING TO
200-400 J/KG OVER THE EAST HALF OF FCST AREA LATE THIS MORNING ALONG
COLD FRONT WHICH SHOULD SUSTAIN SCT TO NMRS SHRA/TSRA INTO EARLY
AFTERNOON UNTIL COLD FRONT PASSES EAST. LINGERING WEAK DIURNAL
INSTABILITY IN LOW-LVLS AND STEEP SFC-8H LAPSE RATES AS NOTED ON
NAM/RUC FCST SNDGS COULD SUPPORT SOME ISOLD SHRA INTO THE EARLY
AFTERNOON AS MID-LVL TROUGH MOVES OVERHEAD. SOME SCT LAKE EFFECT
SHRA COULD ALSO DEVELOP THIS AFTERNOON OVER WRN COUNTIES IN CYCLONIC
NW FLOW AS LAKE SFC DELTA-T/S WILL INCREASE NEAR 13-14C AS 8H TEMPS
DROP TO 5-6C OVER WRN LAKE SUPERIOR.
BIGGER CONCERN MAY BE POTENTIAL FOR ADVISORY WINDS OVER THE KEWEENAW
PENINSULA AND SHORELINE AREAS OF ALGER LUCE COUNTIES THIS AFTERNOON
INTO TONIGHT. MODELS PARTICULARLY NAM SUGGEST AN AREA OF PRES RISES
(4-5 MB OVER 6HR PERIOD) COMBINED WITH PASSAGE OF SECONDARY COLD
FRONT AND INCREASING INSTABILITY SHOULD ALLOW 35-40 KT TO MIX TO
SFC. HAVE POSTED WIND ADVISORY OVER THE NRN HOUGHTON-KEWEENAW FOR
THIS AFTERNOON INTO THIS EVENING AND OVER SHORELINE AREAS OF ALGER
AND LUCE COUNTIES TONIGHT.
CONTINUED COLD ADVECTION AS 8H TEMPS DROP TO 3-5C TONIGHT IN
CYCLONIC NW FLOW WILL CONTINUE TO SUPPORT LINGERING LAKE EFFECT RAIN
SHOWERS DOWNWIND OF LAKE SUPERIOR ESPECIALLY OVER ERN COUNTIES WHERE
FETCH WILL BE LONGER ACROSS THE LAKE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 559 AM EDT THU AUG 16 2012
NAM SHOWS A CLOSED 500 MB LOW NEAR JAMES BAY ON FRIDAY AND IT DOES
NOT MOVE MUCH SAT NIGHT. A RIDGE OVER THE WESTERN U.S. SLOWLY MOVES
EAST INTO THE ROCKIES WITH TIME. THERE ARE ALSO NUMEROUS WEAK
SHORTWAVES ROTATING AROUND THE CLOSED 500 MB LOW OVER NE ONTARIO IN
THE DEEP TROUGH THAT IS OVER THE ERN U.S. TIMING THESE WILL BE
DIFFICULT AND THESE WEAK SHORTWAVES COULD KICK OFF SOME
SHOWERS...ESPECIALLY DIURNAL HEATING OF THE DAY SHOWERS. DID NOT
MAKE TOO MANY CHANGES TO THE GOING FORECAST. MADE JUST A FEW
ADJUSTMENTS TO TEMPERATURES HERE AND THERE. SLIGHT CHANCE POPS FOR
LATE FRI NIGHT INTO SATURDAY LOOK GOOD ESPECIALLY OVER THE EASTERN
CWA AS ANOTHER SHORTWAVE LOOKS TO BE MOVING THROUGH.
IN THE EXTENDED...GFS AND ECMWF HAVE A DEEP TROUGH OVER THE EASTERN
HALF OF N.A. WITH A RIDGE IN THE WESTERN HALF 12Z SUN. PATTERN DOES
NOT CHANGE UNTIL TUE WHEN THE RIDGE MOVES INTO THE ROCKIES AND THE
TROUGH OVER THE ERN U.S. STARTS TO HEAD EAST AND DE-AMPLIFY A BIT.
COLDER THAN NORMAL TEMPERATURES WILL BEGIN THE PERIOD WITH A SLOW
WARM-UP THIS PERIOD. WITH TROUGHING IN THE AREA THROUGH
MONDAY...DIURNAL SHOWERS ARE DEFINITELY POSSIBLE. A SHORTWAVE
AFFECTS THE AREA FOR WED AND WILL HAVE SLIGHT CHANCE TO LOW CHANCE
POPS IN. TEMPERATURES WARM BACK TO NEAR NORMAL ON TUE AND WED. WILL
CONTINUE DRY FOR MONDAY NIGHT AND TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 758 AM EDT THU AUG 16 2012
A COLD FRONT MOVING ACROSS THE AREA WL BRING THE THREAT OF SHRA AND
PERHAPS A TS TO KSAW THIS MORNING. HOWEVER...CONFIDENCE IS LOW THAT
A TSRA WILL MOVE DIRECTLY OVER THE AIRPORT SO DID NOT INCLUDE AN
EXPLICIT MENTION IN TAF. BEHIND THE FROPA AT KIWD AND KCMX...A WSHFT
TO THE WNW WL ADVECT COOLER AND MOISTER LLVL AIR INTO THE
AREA...RESULTING IN LO CLDS/MVFR CONDITIONS AND STRENGTHENING WINDS.
THE STRONGER WINDS AOA 35 KT AND BETTER CHC FOR UPSLOPE/LAKE EFFECT
SHRA WL BE AT THE MORE EXPOSED CMX SITE WITH A MORE PRONOUNCED
UPSLOPE WIND COMPONENT. EXPECT THESE LO CIGS TO SLOWLY LIFT LATE
THIS AFTERNOON AND TONIGHT REACHING VFR AT KIWD TOWARD EVENING AND
VFR AT KCMX OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 559 AM EDT THU AUG 16 2012
AS A COLD FRONT MOVES THROUGH LAKE SUPERIOR THIS MORNING...EXPECT A
SHARP WIND SHIFT TO THE WEST FOLLOWING THIS FRONTAL PASSAGE. THE
ARRIVAL OF MUCH COOLER AIR IN THE WAKE OF THE FRONT OVER THE WARM
WATERS OF LAKE SUPERIOR WILL ALSO RESULT IN ENHANCED MIXING OVER THE
LAKE WITH W-NW WINDS UP TO 30 KTS AND GALES TO 40 KNOTS OVER MOST OF
LAKE SUPERIOR THIS AFTERNOON THROUGH TONIGHT AND HAVE POSTED A GALE
WARNING FOR THIS. EXPECT THE STRONGER NW WINDS TO SLOWLY SUBSIDE ON
FRI THRU THE WEEKEND AS THE PRES GRADIENT WEAKENS WITH BROAD HIGH
PRESSURE SETTLING OVER THE REGION. THERE IS ALSO AN INCREASED RISK
OF RIP CURRENTS IN MARQUETTE AND ALGER COUNTIES THROUGH FRIDAY WITH
STRONG NORTHWEST WINDS AND HIGH WAVES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND ADVISORY FROM 1 PM THIS AFTERNOON TO MIDNIGHT EDT TONIGHT
FOR MIZ001-003.
WIND ADVISORY FROM 9 PM THIS EVENING TO 8 AM EDT FRIDAY FOR
MIZ006-007.
LAKE SUPERIOR...
GALE WARNING FROM 10 PM THIS EVENING TO 11 AM EDT FRIDAY FOR
LSZ267.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 10 AM EDT FRIDAY FOR
LSZ264>266.
GALE WARNING FROM 1 PM THIS AFTERNOON TO 1 AM EDT FRIDAY FOR
LSZ263.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 8 PM EDT THIS EVENING
FOR LSZ244-245.
GALE WARNING FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING
FOR LSZ242-243.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...07
AVIATION...VOSS
MARINE...07
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1002 AM CDT THU AUG 16 2012
.UPDATE...
EXPANDED COVERAGE OF ISOLATED RAIN SHOWERS THIS MORNING AND EARLY
AFTERNOON FURTHER TO THE SOUTH...AND INCREASED TEMPS 1-2 DEG TO
MATCH WITH CURRENT OBSERVATIONS. OTHERWISE...FORECAST LOOKS ON
TRACK.
&&
.PREV DISCUSSION... /ISSUED 634 AM CDT THU AUG 16 2012/
AVIATION...08/16/12Z ISSUANCE...
MVFR OR HIGH-END IFR IN CLOUDS IMPROVING TO MID-RANGE MVFR ABOUT
NOON AND TO VFR CLEAR EARLY THIS EVENING THROUGH TONIGHT.
PREV DISCUSSION... /ISSUED 344 AM CDT THU AUG 16 2012/
SHORT TERM...MSAS SHOWS SFC FRNTL BDRY HAS PUSHED INTO ERN WISC
ZONES EARLY THIS MORNING. PRESSURE IS RISING RAPIDLY BEHIND FRONT
AND GUSTY W/NW WINDS ARE INCREASING. A LARGE CANOPY OF POST
FRONTAL LOW CLOUDS IS OCCURRING WITHIN A DEEP MOIST CIRCULATION
GENERATED BY MID LVL TROF STRETCHING FROM ONTARIO SOUTH TO NRN
IOWA. LATEST WV IMAGERY AND RAP ANALYSIS SHOWS A MID LVL SHORTWAVE
TROF MOVING TOWARDS NWRN MN. BEHIND THIS FEATURE...A SECONDARY
FRONTAL SYSTEM IS INDICATED BY THE 925H THETAE FIELD.
TODAY...SECONDARY SHORTWAVE WILL SWEEP SE QUICKLY THIS MORNING AND
EXIT THE NORTH SHORE OF LAKE SUPERIOR BY MIDDAY. SUFFICIENT MSTR
RESIDES WITHIN THE CYCLONIC FLOW TODAY SO SHOWERS WILL BE OCCURRING
ACROSS THE NRN MN ZONES. A BIT CHALLENGING TO PREDICT WHERE THE
PRECIP/NO PRECIP ZONE WILL LIE EXACTLY. CLOUDS WILL BE PREVALENT
IN MOST AREAS THROUGH 18Z...BEFORE A MORE SERIOUS CLEARING TREND
DEVELOPS. LATEST NAM12 FCST AND BUFKIT PROFILES INDICATE 25-35MPH
GUSTS ARE POSSIBLE TODAY. ALONG THE NORTH SHORE THIS AFTN LOCALIZED
HIGHER WINDS ARE POSSIBLE AS AIR DESCENDS FROM HIGHER ELEVATION OF
COOK/LAKE COUNTY DOWN TO LAKE FRONT. MOST SIGNIFICANT COLD
ADVECTION IN BDRY LYR IS FOCUSED OVER ARROWHEAD SO MAX TEMPS MAY
BE SIGNIFICANTLY LOWER THAN SWRN CWA WHERE MORE NEUTRAL ADVECTION
OCCURS BY AFTN.
TONIGHT/TOMORROW...NO MAJOR CHANGES MADE TO EXISTING FCST EXCEPT
TO LOWER POPS FRIDAY OVER ARROWHEAD. SFC HIGH WILL SLOWLY APPROACH
THE CWA AS DEEP UPPER TROF CRAWLS EAST. INHERITED MIN TEMPS LOOK A
BIT ON THE LOW SIDE CONSIDERING SOME AMOUNT OF MIXING IS IMPLIED
BY THE FCST SFC PRESS GRADIENT AND POTENTIAL FOR FEW MORE CLOUDS
IN NW FLOW ALOFT. CURRENT FCST VALUES ARE ON LOW EDGE OF LATEST
SREF 2M TEMP PLUMES SO WE MAY NEED SOME TWEAK UPWARDS IN LATER
FORECASTS. A MID LVL SHORTWAVE TROF WILL APPROACH THE BORDERLAND
AND THE ARROWHEAD LATE FRIDAY. MDL CONSENSUS IS THAT ANY PRECIP
WILL BE SLOW TO ARRIVE.
LONG TERM...FRIDAY NIGHT THROUGH THURSDAY...
SHORT WAVES ROTATING AROUND THE JAMES BAY UPPER TROUGH WILL PROVOKE
A FEW MOSTLY AFTERNOON AND EVENING SHOWERS OR THUNDERSTORMS ACROSS
THE AREA THROUGH THE COMING WEEKEND. A MORE ZONAL FLOW WILL DRY OUR
AREA OUT MONDAY AND TUESDAY. AFTERNOON TEMPERATURES AROUND 70 THIS
WEEKEND WILL WARM TO THE MID OR UPPER 70S MONDAY AND GET INTO THE
80S TUESDAY. A COLD FRONT FROM CENTRAL CANADA AND A DIGGING TROUGH
ALOFT WILL BRING SCATTERED THUNDERSTORMS WEDNESDAY AND THURSDAY.
&&
.POINT TEMPS/POPS...
DLH 65 45 68 49 / 20 0 10 10
INL 61 43 71 44 / 30 10 20 10
BRD 67 45 70 51 / 20 0 0 10
HYR 66 43 68 44 / 20 0 10 10
ASX 69 47 71 47 / 20 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LSZ121-
144>148.
SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LSZ140>143.
&&
$$
SHORT TERM...TENTINGER
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
634 AM CDT THU AUG 16 2012
.AVIATION...08/16/12Z ISSUANCE...
MVFR OR HIGH-END IFR IN CLOUDS IMPROVING TO MID-RANGE MVFR ABOUT
NOON AND TO VFR CLEAR EARLY THIS EVENING THROUGH TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 344 AM CDT THU AUG 16 2012/
SHORT TERM...MSAS SHOWS SFC FRNTL BDRY HAS PUSHED INTO ERN WISC
ZONES EARLY THIS MORNING. PRESSURE IS RISING RAPIDLY BEHIND FRONT
AND GUSTY W/NW WINDS ARE INCREASING. A LARGE CANOPY OF POST
FRONTAL LOW CLOUDS IS OCCURRING WITHIN A DEEP MOIST CIRCULATION
GENERATED BY MID LVL TROF STRETCHING FROM ONTARIO SOUTH TO NRN
IOWA. LATEST WV IMAGERY AND RAP ANALYSIS SHOWS A MID LVL SHORTWAVE
TROF MOVING TOWARDS NWRN MN. BEHIND THIS FEATURE...A SECONDARY
FRONTAL SYSTEM IS INDICATED BY THE 925H THETAE FIELD.
TODAY...SECONDARY SHORTWAVE WILL SWEEP SE QUICKLY THIS MORNING AND
EXIT THE NORTH SHORE OF LAKE SUPERIOR BY MIDDAY. SUFFICIENT MSTR
RESIDES WITHIN THE CYCLONIC FLOW TODAY SO SHOWERS WILL BE OCCURRING
ACROSS THE NRN MN ZONES. A BIT CHALLENGING TO PREDICT WHERE THE
PRECIP/NO PRECIP ZONE WILL LIE EXACTLY. CLOUDS WILL BE PREVALENT
IN MOST AREAS THROUGH 18Z...BEFORE A MORE SERIOUS CLEARING TREND
DEVELOPS. LATEST NAM12 FCST AND BUFKIT PROFILES INDICATE 25-35MPH
GUSTS ARE POSSIBLE TODAY. ALONG THE NORTH SHORE THIS AFTN LOCALIZED
HIGHER WINDS ARE POSSIBLE AS AIR DESCENDS FROM HIGHER ELEVATION OF
COOK/LAKE COUNTY DOWN TO LAKE FRONT. MOST SIGNIFICANT COLD
ADVECTION IN BDRY LYR IS FOCUSED OVER ARROWHEAD SO MAX TEMPS MAY
BE SIGNIFICANTLY LOWER THAN SWRN CWA WHERE MORE NEUTRAL ADVECTION
OCCURS BY AFTN.
TONIGHT/TOMORROW...NO MAJOR CHANGES MADE TO EXISTING FCST EXCEPT
TO LOWER POPS FRIDAY OVER ARROWHEAD. SFC HIGH WILL SLOWLY APPROACH
THE CWA AS DEEP UPPER TROF CRAWLS EAST. INHERITED MIN TEMPS LOOK A
BIT ON THE LOW SIDE CONSIDERING SOME AMOUNT OF MIXING IS IMPLIED
BY THE FCST SFC PRESS GRADIENT AND POTENTIAL FOR FEW MORE CLOUDS
IN NW FLOW ALOFT. CURRENT FCST VALUES ARE ON LOW EDGE OF LATEST
SREF 2M TEMP PLUMES SO WE MAY NEED SOME TWEAK UPWARDS IN LATER
FORECASTS. A MID LVL SHORTWAVE TROF WILL APPROACH THE BORDERLAND
AND THE ARROWHEAD LATE FRIDAY. MDL CONSENSUS IS THAT ANY PRECIP
WILL BE SLOW TO ARRIVE.
LONG TERM...FRIDAY NIGHT THROUGH THURSDAY...
SHORT WAVES ROTATING AROUND THE JAMES BAY UPPER TROUGH WILL PROVOKE
A FEW MOSTLY AFTERNOON AND EVENING SHOWERS OR THUNDERSTORMS ACROSS
THE AREA THROUGH THE COMING WEEKEND. A MORE ZONAL FLOW WILL DRY OUR
AREA OUT MONDAY AND TUESDAY. AFTERNOON TEMPERATURES AROUND 70 THIS
WEEKEND WILL WARM TO THE MID OR UPPER 70S MONDAY AND GET INTO THE
80S TUESDAY. A COLD FRONT FROM CENTRAL CANADA AND A DIGGING TROUGH
ALOFT WILL BRING SCATTERED THUNDERSTORMS WEDNESDAY AND THURSDAY.
&&
.POINT TEMPS/POPS...
DLH 64 45 68 49 / 10 0 10 10
INL 62 41 71 44 / 30 10 20 10
BRD 68 45 70 51 / 10 0 0 10
HYR 68 44 68 44 / 20 0 10 10
ASX 68 47 71 47 / 20 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LSZ121-
144>148.
&&
$$
SHORT TERM...CANNON
LONG TERM....EOM
AVIATION...EOM
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1051 AM CDT THU AUG 16 2012
.UPDATE...
ISSUED AT 1051 AM CDT THU AUG 16 2012
COLD FRONT HAS NOW MOVED TO NEAR A EOK-IRK-SZL AT 15Z. MAIN CLUSTER
OF THUNDERSTORMS ARE STAYING NORTH AND NORTHEAST OF THE CWA AHEAD
OF A VORT MAX OVER FAR EASTERN IOWA. STILL EXPECT SOME DEVELOPMENT
FARTHER SOUTH THE NEXT FEW HOURS AS THE RAP IS SHOWING DECENT SURFACE-
850MB MOISTURE CONVERGENCE DEVELOPING ALONG THE FRONT BETWEEN 18-21Z.
LATEST SPC OBJECTIVE ANALYSIS IS SHOWING MIXED LAYER CAPES OF 2000-2500
J/KG SOUTH OF THE FRONT WITH RAP FORECAST SOUNDINGS SHOWING THE CINH
ERODING BY EARLY AFTERNOON. PREDOMINANT CONVECTIVE MODE STILL LOOKS
LIKE IT WILL BE FROM MULTI-CELL STORMS AS BEST DEEP LAYER SHEAR
REMAINS NORTH OF THE AREA.
HAVE TRIMMED BACK LIKELY POPS FROM CENTRAL MISSOURI INTO WEST
CENTRAL ILLINOIS WHERE THE FRONT HAS ALREADY MOVED SOUTH. FARTHER
SOUTH...HAVE MAINTAINED LIKELY POPS AHEAD OF THE FRONT GIVEN THAT
LOW LEVEL CONVERGENCE WILL BE PERSISTENT WITH THE ERODING CINH.
WILL KEEP CHANCE POPS OVER NORTHEAST MISSOURI AND WEST CENTRAL
ILLINOIS THIS AFTERNOON WHICH WILL HAVE WEAK ASCENT FROM THE TAIL
END OF THE MAIN SHORTWAVE TROUGH MOVING EAST THROUGH THE UPPER
MIDWEST.
BRITT
&&
.SHORT TERM...
ISSUED AT 248 AM CDT THU AUG 16 2012
(TODAY AND TONIGHT)
AS OF THIS WRITING...THE CDFNT THAT IS EXPECTED TO BRING TSRA TO
THE REGION TODAY IS JUST NOW REACHING FAR NWRN TIP OF MO. THE
FORECAST WILL LIKELY TAKE ON A NUMBER OF ITERATIONS TODAY AS A
NUMBER OF QUESTIONS REMAIN WITH MDLS OFFERING A WIDE VARIETY OF
SOLNS.
STRONG WAA EVIDENT IN SATELLITE IMAGERY THIS MORNING WITH ACCAS
AND ISOD SHRA ALREADY DEVELOPED IN CNTL IL STRETCHING WWD INTO W
CNTL IL. WHILE THIS IS DEPICTED IN THE NAM...THE NAM OBVIOUSLY
DOES NOT HAVE ENUF OF A CAP IN PLACE GIVEN FORECAST SOUNDINGS AND
PRECIP OUTPUT. THIS STRONG WAA SHUD ALSO HELP TO PUT A CAP IN
PLACE AHEAD OF THE CDFNT PREVENTING ANY CONVECTION UNTIL EITHER
LATE THIS MORNING OR INTO THE AFTERNOON.
IN GENERAL...BELIEVE TSRA WILL BE LIMITED TO NRN COUNTIES LATE
THIS MORNING AS ONGOING TSRA DIMINISH WITH LOSS OF LLJ. SINCE THE
BEST FORCING AND WEAKEST CAP WILL BE ALONG THE FNT...HAVE TIMED
THE HIGHEST POPS TO BE CO-LOCATED WITH THE FNT. THAT SAID...WITH
DEWPOINTS REACHING INTO THE UPPER 60S...IT SHUD NOT TAKE TOO MUCH
HEATING FOR PARCELS TO BECOME UNSTABLE.
AS FOR THE SVR THREAT...MDLS CONTINUE TO PROG K INDEX VALUES
AROUND 40C. THIS WUD NORMALLY SUGGEST TSRA WILL BE TOO WATER LADEN
TO PRODUCE MUCH IN THE WAY OF SVR WX. HOWEVER...MDL MOISTURE
PROFILE MAY BE OVERDONE. EVEN IF TSRA ARE WATER LADEN...STEEP LOW
LEVEL LAPSE RATES WILL POSE A WIND THREAT ACROSS THE REGION. ANY
OUTFLOW BOUNDARY MAY MODIFY THE ENVIRONMENT AND INCREASE SHEAR
ENUF TO SUPPORT LARGE HAIL LATER IN THE DAY. THIS THREAT SHUD
LINGER INTO AT LEAST THE EARLY EVENING.
THE NAM IS NOW THE ONLY MDL SUGGESTING STRONG FRONTOGENESIS THIS
EVENING PRODUCING TSRA BEHIND THE FNT. WHILE THIS WUD GENERALLY
SUGGEST SHRA...PROG SOUNDINGS HAVE ELEVATED PARCELS UNCAPPED WITH
STRONG FORCING AND HIGH CAPE. IT IS DOUBTFUL HOWEVER THAT ANY SVR
TSRA WILL OCCUR BEHIND THE FNT AS EARLIER ACTIVITY WILL GREATLY
MODIFY THE ATMO AS THE FNT MOVES THRU THE REGION.
AS FOR TEMPS...HAVE TRENDED TWD THE WARM SOLNS...ESP S OF THE FNT.
ALSO TRENDED TWD THE COOLER SOLNS TONIGHT BEHIND THE FNT AS SKIES
CLEAR OUT ACROSS NRN PORTIONS OF THE CWA. OVERALL...THIS RESULTS
IN VERY FEW CHANGES TO THE PREV FORECAST.
TILLY
&&
.LONG TERM...
ISSUED AT 338 AM CDT THU AUG 16 2012
(SATURDAY THROUGH WEDNESDAY)
BEHIND THE CDFNT MENTIONED ABOVE...A LARGE SFC RIDGE WILL SETTLE
INTO THE REGION. HAVE KEPT SLIGHT CHANCE POPS FRI MORNING TO
ACCOUNT FOR ANY LINGERING TSRA LEFT OVER FROM TONIGHT BUT BULK OF
THE ACTIVITY IS EXPECTED TO BE S OF THE CWA.
NW FLOW WILL SETTLE OVER THE REGION WHICH PRESENTS A BIG FORECAST
CHALLENGE. ANY SUBTLE S/W MAY BE ENUF TO GENERATE PRECIP. MDLS
STILL IN GENERALLY GOOD AGREEMENT WITH A S/W DROPPING INTO THE
REGION LATE SAT INTO SUN. HOWEVER...WITH MUCH OF THE MO/IL REGION
LACKING MUCH IN THE WAY OF MOISTURE...IT CURRENTLY APPEARS THIS
S/W WILL NOT GENERATE PRECIP FOR THE CWA.
OTHERWISE...FORECAST REMAINS DRY THRU THE PERIOD WITH BELOW
SEASONAL AVERAGE TEMPS. MDLS IN FAIRLY GOOD AGREEMENT THRU TUES
WITH THE AREA REMAINING IN NW FLOW. BEYOND TUES...THE ECMWF/GEM
SUGGEST A SYSTEM REINFORCING THE UPPER TROF WHILE THE GFS SUGGESTS
THE UPPER RIDGE STARTING TO BUILD BACK INTO THE REGION. DUE TO THE
LARGE DIFFERENCES...HAVE TRENDED TWD A BLEND OF GUIDANCE WHICH
RESULTS NEAR CLIMO. WILL MAKE ADJUSTMENTS AS MDLS COME INTO BETTER
AGREEMENT.
TILLY
&&
.AVIATION...
ISSUED AT 630 AM CDT THU AUG 16 2012
LOTS OF UNCERTAINTY WITH REGARDS TO THE SHOWER AND THUNDERSTORM
THREAT AT THE TERMINALS. MODEL SOLUTIONS WOULD SUGGEST THERE
SHOULD ALREADY BE SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
NORTHERN MISSOURI INTO CENTRAL ILLINOIS...AND THIS IS NOT THE
CASE. SEEMS LIKE THE BEST THREAT OF SHOWERS AND THUNDERSTORMS
SHOULD BE IN A 2-3 HOUR WINDOW IN ADVANCE OF THE COLD FRONT
PASSAGE AND THAT IS HOW THE TERMINALS HAVE BEEN COMPOSED. GIVEN
THE UNCERTAINTY I HAVE JUST MENTIONED SHOWERS IN KUIN AND KCOU.
TIMING OF THE FRONT THROUGH THE ST LOUIS AREA IS BETTER FOR
THUNDERSTORMS WITH PASSAGE DURING PEAK INSTABILITY. SOME OF THE
PREVIOUS MODEL SOLUTIONS WERE SUGGESTING A WEST-EAST BAND OF POST-
FRONTAL RAIN WOULD DEVELOP THIS EVENING ALONG OR JUST SOUTH OF
INTERSTATE 70. THIS SCENARIO HAS BECOME AN OUTLIER IN THE CURRENT
DATA AND THEREFORE HAVE BEGUN TO DOWNPLAY IT AND JUST MENTIONED
VCSH. EXPECTING VFR CONDITIONS TO PREVIAL OUTSIDE OF ANY
PRECIPITATION.
SPECIFICS FOR KSTL...
HAVE BACKED OFF ON THE TIMING OF ANY PRECIPITATION THREAT IN THE
NEW FORECAST. SEEMS LIKE THE BEST THREAT OF SHOWERS AND THUNDERSTORMS
SHOULD BE IN A 2-3 HOUR WINDOW IN ADVANCE OF THE COLD FRONT PASSAGE...AND
THE CURRENT PROJECTION HAS FROPA AROUND 21Z. SOME OF THE PREVIOUS
MODEL SOLUTIONS WERE SUGGESTING A WEST-EAST BAND OF POST-FRONTAL
RAIN WOULD DEVELOP THIS EVENING ALONG OR JUST SOUTH OF INTERSTATE
70. THIS SCENARIO HAS BECOME AN OUTLIER IN THE CURRENT DATA AND
THEREFORE HAVE BEGUN TO DOWNPLAY IT AND JUST MENTIONED VCSH.
EXPECTING VFR CONDITIONS TO PREVIAL OUTSIDE OF ANY PRECIPITATION.
GLASS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1059 AM EDT THU AUG 16 2012
.SYNOPSIS...
HIGH PRESSURE WILL BRING SUNNY AND WARM WEATHER TO WESTERN NEW YORK
TODAY. THEN A COLD FRONT WILL MOVE THROUGH THE AREA LATE TONIGHT...
PRODUCING A BAND OF SHOWERS AND THUNDERSTORMS. FOLLOWING THE PASSAGE
OF THE COLD FRONT EXPECT COOLER TEMPERATURES AND LESS HUMID
CONDITIONS FOR THIS UPCOMING WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
FOR THE REST OF THE MORNING AND AFTERNOON HOURS...A COMBINATION OF
A WEAK LAKE BOUNDARY OVER EASTERN LAKE ONTARIO AND GENERAL
INSTABILITY OVER THE EASTERN LAKE ONTARIO REGION WILL BE ENOUGH TO
GENERATE SOME SHOWER ACTIVITY. WILL FOCUS ON AN AREA BETWEEN
WATERTOWN AND ROUTE 49 BASED ON SATELLITE IMAGERY AND WEAK
CONVERGENCE IN RUC ANALYSIS. HAVE UPDATED THE FORECASTS FOR THE
EASTERN LAKE ONTARIO REGION AND ISSUED A NOWCAST TO COVER THIS AS
EARLIER FORECASTS WERE FOCUSED ON LARGER SCALE FEATURES. SBCAPE IS
FORECAST TO LOWER WITH TIME...SO ANY ADDITIONAL SHOWERS THAT FORM
THIS MORNING OR EARLY AFTERNOON SHOULD FALL APART AND/OR HEAD INTO
THE ADIRONDACKS WITHOUT ADDITIONAL DEVELOPMENT LATER THIS
AFTERNOON AS THE TYPICAL SUMMER LAKE BREEZE SETS UP. GOT TO LOVE
THOSE LAKES...
A LARGE BUT WEAK AND ELEVATED MCS IS WORKING ITS WAY EASTWARD INTO
SW MI AND NORTHERN IL AT 14Z. SATELLITE IR IMAGERY SHOWS WARMING
TOPS A LOWER CG STRIKES...INDICATING A WEAKENING TREND. THIS
FEATURE IS WITHIN A NARROW WARM SECTOR AND AHEAD OF A COLD FRONT
THAT IS FORECAST TO SWEEP ACROSS NY LATER TONIGHT AND EARLY
FRIDAY. LINEAR EXTRAPOLATION TAKES THIS FEATURE TO THE SOUTHWEST
CORNER OF THE STATE BEFORE SUNSET...AND MATCHES HRRR RUNS...THE
LATEST OF WHICH /11Z RUN/ ACTUALLY KEEPS CONVECTIVE ACTIVITY MAINLY
SOUTH OF THE STATE LINE...BUT STILL MUCH EARLIER OLDER MODEL RUNS.
WILL ADD A CHANCE OF CONVECTION INTO THE EVENING FORECAST FOR THE
EARLIER TIMING FOR AREAS SOUTH OF KBUF.
MOST OF THE GUIDANCE MISSES THE LEADING AREA OF CONVECTION AND
INSTEAD FOCUSES ON A LINE ASSOCIATED WITH THE MAIN COLD
FRONT...WHICH SHOULD NOT ARRIVE IN WESTERN NY UNTIL AROUND OR AFTER
MIDNIGHT AND THEN HEAD EAST INTO CENTRAL NY TOWARD DAYBREAK OR EARLY
FRIDAY. TIMING IS POOR FOR SEVERE WEATHER WITH LOW AND GENERALLY
ELEVATED INSTABILITY...ALTHOUGH THE WARM BOUNDARY LAYER ABOVE LAKE
ERIE WATERS IS NOT WELL HANDLED BY MODEL DATA...WITH OVERNIGHT
CONVECTION OFTEN BLOSSOMING MUCH MORE QUICKLY AND SOMETIMES IN A
MORE ROBUST FASHION THAN MODEL INDICATIONS. CAPE IS SKINNY AND
STRONGER WINDS ALOFT WILL HAVE A TOUGH TIME MIXING DOWN. HOWEVER
WILL LEAVE WORDING NOTING GUSTY WINDS IN THE FORECAST. AM STILL NOT
CONFIDENT ENOUGH TO RAISE THE PROBABILITY OF MEASURABLE RAIN ANY
HIGHER THAN 60-70 PERCENT AS THE EXPECTED LINE STILL HAS YET TO
MATERIALIZE BEHIND THE CURRENT MCS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
THIS PERIOD WILL BEGIN WITH A COLD FRONT ON OUR WESTERN DOORSTEP
FRIDAY MORNING...WITH THE SHORT TERM GUIDANCE IN GOOD AGREEMENT ON
THIS FEATURE THEN RAPIDLY PUSHING EAST AND EXITING INTO EASTERN NEW
YORK/WESTERN NEW ENGLAND BY EARLY TO MID FRIDAY AFTERNOON...OR A
LITTLE QUICKER THAN SEEN IN PREVIOUS RUNS.
IMMEDIATELY ALONG AND AHEAD OF THE BOUNDARY...THE COMBINATION OF LOW
LEVEL CONVERGENCE ALONG THE FRONT AND THE LEADING EDGE OF HEIGHT
FALLS ALOFT WILL HELP TO FORCE A RELATIVELY NARROW BUT FAIRLY
COHESIVE BAND OF SHOWERS...WITH PLENTY ENOUGH LIFT AND MOISTURE
AVAILABLE TO WARRANT A CONTINUATION OF HIGH LIKELY POPS. DESPITE THE
RELATIVELY UNFAVORABLE MORNING TIMING...THERE WILL ALSO BE AT LEAST
A MENTIONABLE CHANCE OF THUNDERSTORMS AS WELL GIVEN THE OVERALL
STRENGTH OF THE LIFT...AND THE POTENTIAL CONTRIBUTION OF MOISTURE/
INSTABILITY FROM THE WARM WATERS OF LAKES ERIE AND ONTARIO. WITH A
FAIRLY UNIDIRECTIONAL SOUTHWESTERLY FLOW ALOFT INCREASING TO 35-40
KTS BETWEEN 850 AND 700 MB...ANY STORMS THAT DO FORM WILL HAVE THE
POTENTIAL TO PRODUCE LOCALLY GUSTY WINDS...AND WILL THEREFORE
CONTINUE TO HIGHLIGHT THIS IN BOTH THE GRIDS/WORDED FORECAST AND HWO.
GIVEN THE TIMING OF THE FRONT...THE GREATEST LIKELIHOOD OF
CONVECTION WILL OCCUR DURING THE MORNING HOURS...WITH STRONG
COOL/DRY AIR ADVECTION AND SUBSIDENCE IN THE WAKE OF THE FRONT THEN
LEADING TO RAPIDLY IMPROVING CONDITIONS FOLLOWING ITS PASSAGE.
EXPECT MOSTLY SUNNY SKIES TO SPREAD ACROSS THE AREA FROM WEST TO
EAST BETWEEN MID MORNING AND MID FRIDAY AFTERNOON...WITH PRECIP
CHANCES ALSO PLUMMETING TO BELOW SLIGHT CHANCE. WITH DECENT MIXING
AND THE RETURN TO SUNSHINE FOLLOWING THE FRONT...850 MB TEMPS OF
+10C TO +13C SHOULD SUPPORT HIGHS IN THE MID 70S IN MOST
LOCATIONS...WITH PERHAPS A SLIGHT DROP-OFF IN TEMPS COMING DURING
THE MID AND LATE AFTERNOON HOURS AS THE COLD AIR ADVECTION REGIME
STRENGTHENS.
AFTER THAT...RELATIVELY QUIET AND COOLER WEATHER IS EXPECTED FOR THE
BALANCE OF THE PERIOD AS LARGE-SCALE UPPER TROUGHING SLOWLY DEEPENS
ACROSS THE GREAT LAKES AND NORTHEAST...WHILE SURFACE HIGH PRESSURE
AND DRIER AIR CONTINUES TO RIDGE NORTHEAST FROM THE OHIO VALLEY.
WHILE TEMPS ALOFT WILL CERTAINLY GET COLD ENOUGH /I.E. +7C TO +9C/
TO SUPPORT A LAKE RESPONSE DOWNWIND OF THE LAKES...THE RELATIVELY
DRY NATURE OF THE AIRMASS AND SHEARED NATURE OF THE LOW TO MID LEVEL
FLOW WILL LIKELY PREVENT MUCH MORE THAN JUST SOME INCREASED STRATOCU
DOWNWIND OF THE LAKES AT POINTS...AND MAINLY DURING NIGHTTIME/EARLY
MORNING PERIODS AT THAT. WITH THE MUCH COOLER AIRMASS ALOFT...TEMPS
WILL EASILY DROP TO BELOW NORMAL LEVELS...WITH DAYTIME HIGHS ON
SATURDAY FALLING BACK TO THE LOWER HALF OF THE 70S...AND NIGHTTIME
LOWS FRIDAY AND SATURDAY NIGHTS DROPPING INTO THE LOWER TO MID
50S...WITH SOME UPPER 40S EVEN POSSIBLE IN INTERIOR VALLEYS OF THE
SOUTHERN TIER.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SUNDAY THROUGH TUESDAY...OUR REGION WILL REMAIN UNDER THE INFLUENCE
OF AN UPPER LOW THAT WILL ONLY SLOWLY MOVE FROM JAMES BAY TO NORTH
CENTRAL QUEBEC. A SERIES OF WEAK SHORTWAVES MIGRATING THROUGH
THE LARGER-SCALE UPPER TROUGH WILL ROTATE ACROSS THE REGION DURING
THIS PERIOD...THOUGH EXPECT NO MORE THAN A SLIGHT CHANCE OF
SHOWERS AS ONLY LIMITED AMOUNTS OF MOISTURE WILL BE AVAILABLE TO
THESE WAVES TO WORK WITH. WITH THE UPPER LEVEL TROUGH REMAINING
THE DOMINANT WEATHER FEATURE...EXPECT SOMEWHAT COOLER THAN NORMAL
BUT COMFORTABLE TEMPS TO ALSO CONTINUE THROUGH TUESDAY.
LATE IN THE PERIOD...THE MAIN UPPER LOW WILL FINALLY GET KICKED OUT
ACROSS LABRADOR AND INTO THE NORTH ATLANTIC...ALLOWING FOR A
FLATTENING QUASI-ZONAL FLOW TO SET UP ACROSS THE GREAT LAKES AND
NORTHEAST. THIS WILL BRING AN END TO THE VERY LOW-END SHOWER
CHANCES...AS WELL AS THE START OF A WARMING TREND AS A WARM AIR
ADVECTION REGIME DEVELOPS ALOFT.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS THIS AFTERNOON WITH HIGH PRESSURE IN PLACE.
FOR TONIGHT A FRONTAL BOUNDARY WILL APPROACH LATE THIS EVENING.
2000FT WINDS WILL INCREASE TO 35 TO 40 KTS FROM WEST TO EAST...BUT
WILL NOT MIX DOWN OVERNIGHT. THIS WILL RESULT IN LLWS...WHICH IS
FORECAST TO BEGIN AT AROUND 04Z AT BUF/IAG/JHW.
THE FRONT IS ALSO LIKELY TO BRING A ROUND OF SHOWERS TO TAF
LOCATIONS LATE TONIGHT. THERE MAY BE SOME THUNDERSTORMS AS
WELL...BUT WITH THESE EXPECTED TO BE SCATTERED IN NATURE...WILL
CARRY -SHRA IN TAFS.
OUTLOOK...
FRIDAY...A PERIOD OF SHOWERS/THUNDERSTORMS WITH ASSOCIATED
MVFR...OTHERWISE VFR.
SATURDAY...POSSIBLE MVFR/IFR IN FOG EARLY OTHERWISE VFR.
SUNDAY...VFR.
MONDAY...CHANCE OF SHOWERS/TSTMS. MAINLY VFR.
&&
.MARINE...
WINDS AND WAVES WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA FOR
TODAY...WITH TYPICAL LAKE BREEZE DEVELOPMENT EXPECTED. TONIGHT AND
FRIDAY...A COLD FRONT WILL CROSS THE LOWER LAKES ALONG WITH THE
LIKELIHOOD OF ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS...SOME OF
WHICH COULD PRODUCE LOCALLY GUSTY WINDS. BEHIND THE FRONT...A BRISK
WESTERLY FLOW OF COOLER AIR WILL SET UP ACROSS LAKE ONTARIO ON
FRIDAY...WITH WINDS AND WAVES POTENTIALLY REACHING ADVISORY CRITERIA.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL/ZAFF
SHORT TERM...JJR
LONG TERM...JJR/WOOD
AVIATION...APFFEL/ZAFF
MARINE...APFFEL
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1036 AM EDT THU AUG 16 2012
.SYNOPSIS...
HIGH PRESSURE WILL BRING SUNNY AND WARM WEATHER TO WESTERN NEW YORK
TODAY. THEN A COLD FRONT WILL MOVE THROUGH THE AREA LATE TONIGHT...
PRODUCING A BAND OF SHOWERS AND THUNDERSTORMS. FOLLOWING THE PASSAGE
OF THE COLD FRONT EXPECT COOLER TEMPERATURES AND LESS HUMID
CONDITIONS FOR THIS UPCOMING WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
A LARGE BUT WEAK AND ELEVATED MCS IS WORKING ITS WAY EASTWARD INTO
SW MI AND NORTHERN IL AT 14Z. SATELLITE IR IMAGERY SHOWS WARMING
TOPS A LOWER CG STRIKES...INDICATING A WEAKENING TREND. THIS
FEATURE IS WITHIN A NARROW WARM SECTOR AND AHEAD OF A COLD FRONT
THAT IS FORECAST TO SWEEP ACROSS NY LATER TONIGHT AND EARLY
FRIDAY. LINEAR EXTRAPOLATION TAKES THIS FEATURE TO THE SOUTHWEST
CORNER OF THE STATE BEFORE SUNSET...AND MATCHES HRRR RUNS...THE
LATEST OF WHICH /11Z RUN/ ACTUALLY KEEPS CONVECTIVE ACTIVITY MAINLY
SOUTH OF THE STATE LINE...BUT STILL MUCH EARLIER OLDER MODEL RUNS.
WILL ADD A CHANCE OF CONVECTION INTO THE EVENING FORECAST FOR THE
EARLIER TIMING FOR AREAS SOUTH OF KBUF.
MOST OF THE GUIDANCE MISSES THE LEADING AREA OF CONVECTION AND
INSTEAD FOCUSES ON A LINE ASSOCIATED WITH THE MAIN COLD
FRONT...WHICH SHOULD NOT ARRIVE IN WESTERN NY UNTIL AROUND OR AFTER
MIDNIGHT AND THEN HEAD EAST INTO CENTRAL NY TOWARD DAYBREAK OR EARLY
FRIDAY. TIMING IS POOR FOR SEVERE WEATHER WITH LOW AND GENERALLY
ELEVATED INSTABILITY...ALTHOUGH THE WARM BOUNDARY LAYER ABOVE LAKE
ERIE WATERS IS NOT WELL HANDLED BY MODEL DATA...WITH OVERNIGHT
CONVECTION OFTEN BLOSSOMING MUCH MORE QUICKLY AND SOMETIMES IN A
MORE ROBUST FASHION THAN MODEL INDICATIONS. CAPE IS SKINNY AND
STRONGER WINDS ALOFT WILL HAVE A TOUGH TIME MIXING DOWN. HOWEVER
WILL LEAVE WORDING NOTING GUSTY WINDS IN THE FORECAST. AM STILL NOT
CONFIDENT ENOUGH TO RAISE THE PROBABILITY OF MEASURABLE RAIN ANY
HIGHER THAN 60-70 PERCENT AS THE EXPECTED LINE STILL HAS YET TO
MATERIALIZE BEHIND THE CURRENT MCS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
THIS PERIOD WILL BEGIN WITH A COLD FRONT ON OUR WESTERN DOORSTEP
FRIDAY MORNING...WITH THE SHORT TERM GUIDANCE IN GOOD AGREEMENT ON
THIS FEATURE THEN RAPIDLY PUSHING EAST AND EXITING INTO EASTERN NEW
YORK/WESTERN NEW ENGLAND BY EARLY TO MID FRIDAY AFTERNOON...OR A
LITTLE QUICKER THAN SEEN IN PREVIOUS RUNS.
IMMEDIATELY ALONG AND AHEAD OF THE BOUNDARY...THE COMBINATION OF LOW
LEVEL CONVERGENCE ALONG THE FRONT AND THE LEADING EDGE OF HEIGHT
FALLS ALOFT WILL HELP TO FORCE A RELATIVELY NARROW BUT FAIRLY
COHESIVE BAND OF SHOWERS...WITH PLENTY ENOUGH LIFT AND MOISTURE
AVAILABLE TO WARRANT A CONTINUATION OF HIGH LIKELY POPS. DESPITE THE
RELATIVELY UNFAVORABLE MORNING TIMING...THERE WILL ALSO BE AT LEAST
A MENTIONABLE CHANCE OF THUNDERSTORMS AS WELL GIVEN THE OVERALL
STRENGTH OF THE LIFT...AND THE POTENTIAL CONTRIBUTION OF MOISTURE/
INSTABILITY FROM THE WARM WATERS OF LAKES ERIE AND ONTARIO. WITH A
FAIRLY UNIDIRECTIONAL SOUTHWESTERLY FLOW ALOFT INCREASING TO 35-40
KTS BETWEEN 850 AND 700 MB...ANY STORMS THAT DO FORM WILL HAVE THE
POTENTIAL TO PRODUCE LOCALLY GUSTY WINDS...AND WILL THEREFORE
CONTINUE TO HIGHLIGHT THIS IN BOTH THE GRIDS/WORDED FORECAST AND HWO.
GIVEN THE TIMING OF THE FRONT...THE GREATEST LIKELIHOOD OF
CONVECTION WILL OCCUR DURING THE MORNING HOURS...WITH STRONG
COOL/DRY AIR ADVECTION AND SUBSIDENCE IN THE WAKE OF THE FRONT THEN
LEADING TO RAPIDLY IMPROVING CONDITIONS FOLLOWING ITS PASSAGE.
EXPECT MOSTLY SUNNY SKIES TO SPREAD ACROSS THE AREA FROM WEST TO
EAST BETWEEN MID MORNING AND MID FRIDAY AFTERNOON...WITH PRECIP
CHANCES ALSO PLUMMETING TO BELOW SLIGHT CHANCE. WITH DECENT MIXING
AND THE RETURN TO SUNSHINE FOLLOWING THE FRONT...850 MB TEMPS OF
+10C TO +13C SHOULD SUPPORT HIGHS IN THE MID 70S IN MOST
LOCATIONS...WITH PERHAPS A SLIGHT DROP-OFF IN TEMPS COMING DURING
THE MID AND LATE AFTERNOON HOURS AS THE COLD AIR ADVECTION REGIME
STRENGTHENS.
AFTER THAT...RELATIVELY QUIET AND COOLER WEATHER IS EXPECTED FOR THE
BALANCE OF THE PERIOD AS LARGE-SCALE UPPER TROUGHING SLOWLY DEEPENS
ACROSS THE GREAT LAKES AND NORTHEAST...WHILE SURFACE HIGH PRESSURE
AND DRIER AIR CONTINUES TO RIDGE NORTHEAST FROM THE OHIO VALLEY.
WHILE TEMPS ALOFT WILL CERTAINLY GET COLD ENOUGH /I.E. +7C TO +9C/
TO SUPPORT A LAKE RESPONSE DOWNWIND OF THE LAKES...THE RELATIVELY
DRY NATURE OF THE AIRMASS AND SHEARED NATURE OF THE LOW TO MID LEVEL
FLOW WILL LIKELY PREVENT MUCH MORE THAN JUST SOME INCREASED STRATOCU
DOWNWIND OF THE LAKES AT POINTS...AND MAINLY DURING NIGHTTIME/EARLY
MORNING PERIODS AT THAT. WITH THE MUCH COOLER AIRMASS ALOFT...TEMPS
WILL EASILY DROP TO BELOW NORMAL LEVELS...WITH DAYTIME HIGHS ON
SATURDAY FALLING BACK TO THE LOWER HALF OF THE 70S...AND NIGHTTIME
LOWS FRIDAY AND SATURDAY NIGHTS DROPPING INTO THE LOWER TO MID
50S...WITH SOME UPPER 40S EVEN POSSIBLE IN INTERIOR VALLEYS OF THE
SOUTHERN TIER.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SUNDAY THROUGH TUESDAY...OUR REGION WILL REMAIN UNDER THE INFLUENCE
OF AN UPPER LOW THAT WILL ONLY SLOWLY MOVE FROM JAMES BAY TO NORTH
CENTRAL QUEBEC. A SERIES OF WEAK SHORTWAVES MIGRATING THROUGH
THE LARGER-SCALE UPPER TROUGH WILL ROTATE ACROSS THE REGION DURING
THIS PERIOD...THOUGH EXPECT NO MORE THAN A SLIGHT CHANCE OF
SHOWERS AS ONLY LIMITED AMOUNTS OF MOISTURE WILL BE AVAILABLE TO
THESE WAVES TO WORK WITH. WITH THE UPPER LEVEL TROUGH REMAINING
THE DOMINANT WEATHER FEATURE...EXPECT SOMEWHAT COOLER THAN NORMAL
BUT COMFORTABLE TEMPS TO ALSO CONTINUE THROUGH TUESDAY.
LATE IN THE PERIOD...THE MAIN UPPER LOW WILL FINALLY GET KICKED OUT
ACROSS LABRADOR AND INTO THE NORTH ATLANTIC...ALLOWING FOR A
FLATTENING QUASI-ZONAL FLOW TO SET UP ACROSS THE GREAT LAKES AND
NORTHEAST. THIS WILL BRING AN END TO THE VERY LOW-END SHOWER
CHANCES...AS WELL AS THE START OF A WARMING TREND AS A WARM AIR
ADVECTION REGIME DEVELOPS ALOFT.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS THIS AFTERNOON WITH HIGH PRESSURE IN PLACE.
FOR TONIGHT A FRONTAL BOUNDARY WILL APPROACH LATE THIS EVENING.
2000FT WINDS WILL INCREASE TO 35 TO 40 KTS FROM WEST TO EAST...BUT
WILL NOT MIX DOWN OVERNIGHT. THIS WILL RESULT IN LLWS...WHICH IS
FORECAST TO BEGIN AT AROUND 04Z AT BUF/IAG/JHW.
THE FRONT IS ALSO LIKELY TO BRING A ROUND OF SHOWERS TO TAF
LOCATIONS LATE TONIGHT. THERE MAY BE SOME THUNDERSTORMS AS
WELL...BUT WITH THESE EXPECTED TO BE SCATTERED IN NATURE...WILL
CARRY -SHRA IN TAFS.
OUTLOOK...
FRIDAY...A PERIOD OF SHOWERS/THUNDERSTORMS WITH ASSOCIATED
MVFR...OTHERWISE VFR.
SATURDAY...POSSIBLE MVFR/IFR IN FOG EARLY OTHERWISE VFR.
SUNDAY...VFR.
MONDAY...CHANCE OF SHOWERS/TSTMS. MAINLY VFR.
&&
.MARINE...
WINDS AND WAVES WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA FOR
TODAY...WITH TYPICAL LAKE BREEZE DEVELOPMENT EXPECTED. TONIGHT AND
FRIDAY...A COLD FRONT WILL CROSS THE LOWER LAKES ALONG WITH THE
LIKELIHOOD OF ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS...SOME OF
WHICH COULD PRODUCE LOCALLY GUSTY WINDS. BEHIND THE FRONT...A BRISK
WESTERLY FLOW OF COOLER AIR WILL SET UP ACROSS LAKE ONTARIO ON
FRIDAY...WITH WINDS AND WAVES POTENTIALLY REACHING ADVISORY CRITERIA.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL/ZAFF
SHORT TERM...JJR
LONG TERM...JJR/WOOD
AVIATION...APFFEL/ZAFF
MARINE...APFFEL
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1020 AM EDT THU AUG 16 2012
.SYNOPSIS...
HIGH PRESSURE PUSHES EAST THIS AFTERNOON. STRONG COLD FRONT CROSSES
FRIDAY AND FRIDAY EVENING. WEAK HIGH PRESSURE OVER WEEKEND...WITH
DISTURBANCE ALOFT PASSING SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1000AM UPDATE...
FOG/LOW STRATUS HANGING TOUGH ACROSS MTN VALLEYS AND S COAL FIELDS
THIS MORNING. THIS WILL LIFT AND SCT OUT NEXT HR OR SO.
OTHERWISE...WATCHING COMPLEX ASSOCIATED WITH COLD FRONT ACROSS N
IL THIS MORNING. MDLS ARE STRUGGLING WITH THIS CONVECTION TO SAY
THE LEAST. LATEST HRRR SEEMS TO BE CLOSE WITH INITIALIZATION BUT
THEN STRUGGLES WITH TIMING OF EASTERN PROGRESSION AS DAY WEARS ON.
ROUGH TIMING FROM SATELLITE/LIGHTNING STRIKES PUTS IN ON NW
FLANK ARND 21Z. HOWEVER...THINK THIS WILL CONTINUE TO WEAKEN THIS
MORNING BEFORE PERHAPS REFIRING THIS AFTN CLOSER TO FRONT. WILL
LEAVE POPS OUT ATTM ACROSS SE OH FOR LATE THIS AFTN GIVEN DRY AIR
ARND H7 AND MUCH OF SUPPORT REMAINING WELL WEST CLOSER TO FRONT
AND UPR SUPPORT. TRENDS WILL BE MONITORED THOUGH FOR SOME
INCLUSION OF LOW POPS ACROSS SE OH LATE.
PREVIOUS DISCUSSION BELOW...
LIGHT SW FLOW ON THE BACK SIDE OF HIGH PRESSURE EXITING STAGE E
WILL GIVE RISE TO A DRY DAY WITH SUNSHINE ONCE THE DENSE MORNING
FOG BURNS OFF...WITH A WARMER AFTERNOON.
A COLD FRONT AND UPPER LEVEL TROUGH APPROACHES FROM THE W TONIGHT.
THE ONSET OF THE PRECIPITATION IS LIKELY TO COINCIDE WITH THE
LEADING EDGE OF THE THETA E RIDGE AND UPPER LEVEL FORCING. USED A
BLEND OF THE SLOWER SREF / GFS TIMING AND THE FASTER NAM12
TIMING...WHICH TAKES IT TO THE W EDGE OF THE CWA NEAR 06Z...THE OHIO
RIVER AT 09Z AND TO VERY NEAR THE MOUNTAINS 12Z FRI. HAVE THE
CHANCE FOR THUNDER GIVEN ELEVATED INSTABILITY OVER TOP OF THE
STRAIGHT UP STABILITY GRADIENT.
TEMPERATURES AND DEW POINTS LOOKED TO BE CLOSE TO GUIDANCE WITH NO
MAJOR CHANGES NEEDED...ALTHOUGH THERE MAY BE A SMALL RISE W AND ON
THE RIDGES TOWARD DAYBREAK IN THE INCREASINGLY MOIST SW FLOW AHEAD
OF THE COLD FRONT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
THE 00Z NAM WAS THE SLOWEST WITH THE FRONTAL DEEP MOISTURE...THE GFS
APPEARS TO THE THE QUICKEST. THE 12Z ECMWF WAS A NICE COMPROMISE.
ALL MODELS SHOW THE RIGHT REAR OF A 250 MB JET MAX HELPING THE
SYNOPTIC FORCING CENTERED ON 18Z FRIDAY. WITH THAT IN MIND...LIKE
HPC DAY 2 QPF GOING WETTER...AND WETTER THAN THE 00Z GFS.
BASING THE FORECAST ON THE FRONT NOT PASSING CRW UNTIL ABOUT 00Z
SATURDAY. SO WAS A BIT SLOWER DRYING OUT/LOWERING POPS/IN OUR
SOUTHERN COAL FIELDS AND SOUTHERN MOUNTAINS SATURDAY EVENING.
HARD TO GET ANY GOOD HANDLE ON AMOUNT OF BREAKS IN THE CLOUDS...AND
THE INCREASE IN INSTABILITY FOR FRIDAY AFTERNOON. BUT SOUTHERN AND
EASTERN COUNTIES HAVE BEST CHANCE ON MORE INSTABILITY. STEERING FLOW
ABOUT 30 KNOTS ACROSS THE NORTH AND 25 KNOTS FURTHER SOUTH.
HOPE ANY CONVECTIVE CLUSTERS DO NOT BEND OVER TO A MORE EAST/WEST
ORIENTATION IN OUR SOUTHERN COUNTIES...AND THUS INCREASE CHANCE
FOR REPETITIVE ACTION...BY LATE FRIDAY AFTERNOON OR EARLY FRIDAY
EVENING.
FIGURING ON SOME LOW CLOUDS...MAYBE FOG SATURDAY MORNING MAINLY
EKN-CRW ON SOUTH...BUT TOO EARLY TO INSERT FOG INTENSITY. LOWERING
DEW POINTS REACH FURTHER SOUTH SATURDAY AFTERNOON.
LIKELY A SHARP CLOUD AND POP GRADIENT FROM SE TO NW SUNDAY MORNING
WITH DISTURBANCE ALOFT...INCREASING THE DEEPER MOISTURE TO OUR SOUTH
AND EAST. DID INCLUDE SOME CHANCE POPS IN OUR MOUNTAINOUS COUNTIES
LEAVING THE WESTERN LOWLANDS DRY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
USED PREEPD THINKING FOR THIS PORTION OF THE FORECAST. REGION
SHOULD BE UNDER THE INFLUENCE OF SURFACE HIGH PRESSURE...WITH AN
UPPER LEVEL TROF EXPECTED TO MOVE EAST ON TUESDAY.
THIS SHOULD RESULT IN MAINLY DRY WEATHER. HOWEVER...WITH UPPER
LEVEL TROF PUSHING EAST...HAVE GONE WITH DIURNAL SLIGHT CHANCE POPS
ACROSS OUR HIGHER ELEVATIONS.
USED HPC TEMPS WITH SOME TWEAKS.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
VFR DAY TODAY ONCE THE FOG...MAINLY IN THE VALLEYS OF EASTERN WV...
BURNS OFF FIRST THING THIS MORNING. SOME OF IT WILL MIX INTO LOW
CLOUDS THAT WILL THEN QUICKLY SCATTER OUT. HIGH PRESSURE MOVES OFF
TO THE E TODAY...AND CLOUDS INCREASE FROM THE W TONIGHT AS A COLD
FRONT APPROACHES FROM THE W.
SHOWERS AND THUNDERSTORMS ARE LIKELY TO CROSS THE OHIO RIVER BY THE
END OF THE TAF PERIOD...WITH CONDITIONS GETTING DOWN TO AT LEAST VFR
THERE. THE PRECIPITATION MAY MAKE IT AS FAR E AS CRW BY 12Z FRI.
MVFR MIST POSSIBLE IN THE MOUNTAIN VALLEYS OVERNIGHT TONIGHT BEFORE
THE CLOUDS MOVE IN.
SFC FLOW WILL BE LIGHT SW TODAY AND TONIGHT WHILE LIGHT W FLOW ALOFT
THIS MORNING BECOMES LIGHT TO MODERATE W TO SW FOR THIS AFTERNOON
AND TONIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: FOG LIFTING AND MIXING OUT THIS MORNING MAY
VARY FROM TAF CODE. ARRIVAL OF PRECIPITATION EARLY FRI MORNING MAY
ALSO 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 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY M H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY M H H H H H H H H H H H
CKB CONSISTENCY M H H H H H H H H H H H
AFTER 12Z FRIDAY...
IFR POSSIBLE IN THUNDERSTORMS FRI AND IN LOW CLOUDS AND / OR FOG SAT
MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/TRM
NEAR TERM...TRM/30
SHORT TERM...KTB
LONG TERM...JSH
AVIATION...TRM
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1003 AM EDT THU AUG 16 2012
.SYNOPSIS...
WEAK HIGH PRESSURE WILL MOVE EAST TODAY AS A COLD FRONT APPROACHES
THE AREA FROM THE NORTHWEST. THE FRONT IS EXPECTED TO MOVE THROUGH
THE REGION TONIGHT INTO FRIDAY. CANADIAN HIGH PRESSURE WILL THEN
SETTLE ACROSS THE OHIO VALLEY FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CONVECTION MOVING INTO NORTHWEST INDIANA MAKES FOR CHALLENGING
FORECAST. THIS ACTIVITY IS NOT BEING HANDLED WELL BY MOST
NUMERICAL GUIDANCE. THE CLOSEST SEEMS TO BE THE HRRR RUNS AND EVEN
AMONGST THOSE THERE IS VARIABILITY ON CONVECTIVE EVOLUTION.
AT THIS POINT IT SEEMS THAT THESE STORMS WILL CONTINUE EASTWARDS
AND THUS SHOULD IMPACT AT LEAST WEST CENTRAL OHIO THIS AFTERNOON.
HAVE FORECAST SOME WEAKENING AS THIS CONTINUES INTO CENTRAL OHIO.
THEN EXPECT REDEVELOPMENT BACK WEST CLOSER TO A COLD FRONT LATER
IN THE AFTERNOON.
FORECAST HIGHS LOOK REASONABLE BASED ON WARMING LOW LEVELS AS
SAMPLED IN THE MORNING SOUNDING. ONLY QUESTION IS IF CONVECTION
COULD IMPACT READINGS MAINLY IN THE NORTHWEST. FOR THE TIME BEING
HAVE MADE LITTLE CHANGE IN THAT REGARD.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THERE CONTINUES TO BE SOME SUBTLE TIMING DIFFERENCES AMONGST THE
MODELS IN TERMS OF FRONTAL SPEED THROUGH THE REGION TONIGHT INTO
FRIDAY. THE NAM IS THE SLOWEST...THE ECMWF THE SECOND
SLOWEST...WITH THE CMC AND GFS MOST PROGRESSIVE. HAVE LEANED
TOWARD THE CMC/GFS SOLUTIONS BUT ALLOWED FOR SOME LINGERING POST
FRONTAL PCPN IN THE SE ZONES INTO EARLY FRIDAY AFTERNOON.
OTHERWISE...A LINE OF SHOWERS AND THUNDERSTORMS SHOULD BE UNDERWAY
TO OUR WEST EARLY THIS EVENING IN AN AREA OF UPR LVL SUPPORT AND
LOW LEVEL FRONTAL CONVERGENCE. MODERATE SHEAR AND INSTABILITY WILL
LIKELY RENDER THESE STORMS TO BE SEVERE EARLY ON. HOWEVER...AS THE
FRONT PUSHES SOUTHEAST INTO OUR AREA...OVERALL INSTABILITY AND LOW
LEVEL CONVERGENCE WILL SHOW A WEAKENING TREND DURING THE OVERNIGHT
HOURS. AS A RESULT...HAVE GONE WITH CATEGORICAL POPS ACRS THE FAR
WRN/NWRN ZONES...AND THEN TAPERED THEM OFF TO LOW END LIKELY AS
THE PCPN MAKES ITS WAY TO THE SERN ZONES TOWARD FRIDAY MORNING.
AGREE WITH SPC THAT A FEW STORMS MAY STILL BE SEVERE AS THEY HEAD
INTO OUR WESTERN ZONES THIS EVENING INTO EARLY MORNING...SO WILL
HIGHLIGHT THIS THREAT IN THE HWO. DAMAGING WINDS WILL BE THE
PRIMARY SEVERE WEATHER THREAT WITH ISOLATED LARGE HAIL POSSIBLE.
FOR POINTS TO THE EAST/SE...THE SEVERE THREAT APPEARS TO BE
MINIMAL ATTM DUE TO AN EXPECTED WEAKENING TREND OF THE
AFOREMENTIONED PARAMETERS. OVERNIGHT LOWS WILL RANGE FROM THE
LOWER 60S NW TO THE UPPER 60S SE.
ON FRIDAY...LARGE SCALE MID LVL TROUGH WILL CONTINUE TO CARVE
ITSELF ACRS THE GREAT LAKES AND OHIO VALLEY REGION...PUSHING THE
COLD FRONT SOUTHEAST AWAY FROM THE AREA. HIGHEST POPS WILL BE
ONGOING DURING THE MORNING HOURS ACRS THE ERN/SERN ZONES...THEN
THE THREAT FOR RAIN SHOULD END BY THE EARLY AFTERNOON HOURS AS
DRIER AIR FILTERS IN BEHIND THE FRONT. SKIES SHOULD GRADUALLY
BECOME PARTLY CLOUDY FROM NW TO SE WITH SOME POST FRONTAL CAA
CUMULUS CLOUDS EXPECTED. WITH CAA...HIGHS WILL RANGE FROM THE
LOWER 70S NW TO THE UPPER 70S TO NEAR 80 SE.
FOR FRIDAY NIGHT...HIGH PRESSURE OF CANADIAN ORIGIN WILL BUILD
SOUTHEAST INTO THE OHIO VALLEY REGION. SKIES WILL BECOME MOSTLY
CLEAR WITH LIGHT NORTHERLY WINDS. TEMPERATURES WILL COOL
SUBSTANTIALLY FOR MID AUGUST WITH OVERNIGHT LOWS RANGING FROM THE
UPPER 40S NW TO THE MID 50S SE.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE LONG TERM PERIOD WILL BE GENERALLY QUIET AND COMFORTABLE. A
CLOSED UPPER LEVEL LOW WILL REMAIN NEARLY STATIONARY NEAR JAMES BAY
IN CANADA...WITH AN ANOMALOUSLY DEEP LONG WAVE TROUGH EXTENDING INTO
THE EASTERN CONUS THROUGH THE BEGINNING OF NEXT WEEK. AT THE
SFC...HIGH PRESSURE WILL KEEP THE AREA UNDER NORTHERLY FLOW. A
WEAK SHORTWAVE ROUNDING THE TROUGH MAY INCREASE CLOUDS ON SUNDAY.
HAVE PLACED A 20 POP IN THE FAR NORTHERN COUNTIES...BUT WITH
LIMITED MOISTURE AND FORCING...THAT MAY BE GENEROUS. ANY OTHER
EMBEDDED SHORT WAVES LOOK EVEN WEAKER. MODELS ARE IN GOOD
AGREEMENT WITH THE LARGE SCALE FEATURES THROUGH MONDAY. THEN THERE
IS SOME DIVERGENCE AS A TROUGH MOVES ONTO THE WEST COAST AND THE
ENSUING DOWNSTREAM DEAMPLIFICATION OF THE PATTERN TAKES PLACE
DURING THE MIDDLE OF THE WEEK. HOWEVER THIS WILL HAVE LITTLE
IMPACT ON OUR SENSIBLE WEATHER (PERHAPS A FEW DEGREES ON
TEMPERATURES)...WITH THE SFC HIGH REMAINING IN CONTROL AS IT
GRADUALLY SHIFTS TO THE EAST COAST.
850 MB TEMPERATURE ANOMALIES AND ENSEMBLE SPREADS INDICATE THE
COLDEST AIR WILL BE OVER THE REGION ON SATURDAY. COMBINED WITH
DIURNAL CU...ELECTED TO GO A LITTLE BELOW GUIDANCE WITH HIGHS IN THE
LOWER TO MID 70S. THE DRY AIR MASS AND RADIATIONAL COOLING WILL
ALLOW FOR SEVERAL NIGHTS OF LOWS IN THE 50S. TEMPERATURES WILL
GRADUALLY REBOUND THROUGH MID WEEK...ALTHOUGH NOT REACHING
NEAR/SLIGHTLY ABOVE NORMAL VALUES UNTIL TUESDAY/WEDNESDAY WHEN
RETURN FLOW SETS UP. DEW POINTS WILL ONLY MODERATELY RECOVER AS
WELL...REMAINING COMFORTABLE AOB 60F THROUGH THE PERIOD.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE OVER THE EASTERN US WILL SLIDE OFF THE EAST COAST AS
A COLD FRONT EXTENDING FROM WISCONSIN THROUGH EASTERN KANSAS MOVES
SOUTHEAST INTO THE FORECAST AREA TONIGHT.
SCT MID AND HI CLOUDS WILL MOVE SOUTHEAST ACROSS THE AREA
THROUGHOUT THE DAY TIME HOURS. SCT CU EXPECTED TO DEVELOP LATE
LATE THIS MORNING. HI CLOUDS FROM THUNDERSTORMS NW OF THE AREA
WILL THICKEN THROUGHOUT THE AFTERNOON AS THEY SPREAD EAST
SOUTHEASTWARD ACROSS THE AREA.
TONIGHT COLD FRONT WILL APPROACH THE AREA CAUSING CEILINGS TO
GRADUALLY LOWER THROUGHOUT THE NIGHT TIME HOURS. ISOLATED
CONVECTION WILL MOVE INTO WESTERN PORTIONS OF THE FORECAST AREA
LATE THIS EVENING WITH SHOWERS AND THUNDERSTORMS INCREASING TO
LIKELY AROUND MIDNIGHT. HAVE HANDLED THE BEST CHANCE FOR
THUNDERSTORMS IN THE TAF WITH A 3 TO 4 HOUR WINDOW OF PREVAILING
SHOWERS AND VCTS UNTIL TIMING CAN BE NAILED DOWN A LITTLE BETTER
WITH LATER FORECASTS. CONVECTION WILL DECREASE FROM NORTHWEST TO
SOUTHEAST STARTING AROUND 09Z. PATCHY FOG CONDITIONS WILL PRODUCE
MVFR CONDS STARTING AROUND 09Z WITH CEILINGS BECOMING MVFR MOST
AREAS LATE IN THE FORECAST PERIOD.
.OUTLOOK...THUNDERSTORMS POSSIBLE INTO FRIDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...
SHORT TERM...HICKMAN
LONG TERM...HICKMAN/SNYDER
AVIATION...HAYDU
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
353 PM EDT THU AUG 16 2012
.SYNOPSIS...
AN INLAND TROUGH OF LOW PRESSURE WILL PREVAIL THROUGH FRIDAY.
ANOTHER WEAK COLD FRONT WILL APPROACH FROM THE NORTHWEST SATURDAY
BEFORE STALLING JUST NORTH AND WEST OF THE AREA ON SUNDAY AS A
WEAK WAVE OF LOW PRESSURE FORMS ALONG THE FRONT. THE FRONT IS
EXPECTED TO SHIFT ACROSS THE AREA EARLY NEXT WEEK...THEN LINGER
JUST OFFSHORE INTO THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE CONVECTION HAS CERTAINLY TAKEN OFF OVER OUR SOUTHERN AND
CENTRAL COASTAL REGION...SPARKED BY LOW LEVEL BOUNDARY COLLISIONS
AND A WEAK UPPER LEVEL SHORT WAVE MOVING ACROSS CENTRAL GA. HAVE
INCREASED POPS...BUT CONVECTION IS CHANGING IN COVERAGE SO
RAPIDLY...IT IS NEARLY IMPOSSIBLE TO GET THE POPS ALIGNED WITH
REALITY. HAVE ALREADY RECEIVED SEVERAL REPORTS OF LARGE HAIL WITH
THE STORMS AROUND THE SAVANNAH RIVER REGION. EXPECT STORMS TO
PROPAGATE NORTHWARD ALONG SEA BREEZE...WHICH IS PINNED VERY CLOSE
TO THE COAST. HOWEVER...NOT THINKING THE STORMS THAT DEVELOP
FURTHER NORTH WILL BE QUITE AS STRONG AS THE MORE SOUTHERN ONES
DUE TO LOWER CAPE VALUES. HOWEVER...LATEST RUC ANALYSES INDICATING
30-40 KTS OF BULK SHEAR NEAR THE COAST...WHICH COULD ALLOW
ORGANIZED UPDRAFTS AND LONGER LASTING STORMS MOVING UP THE COAST.
SCATTERED STORMS...WHICH SHOULD STAY CONFINED TO MAINLY THE
COASTAL THIRD OF THE REGION...WILL DISSIPATE BY THE EVENING...BUT
LIKELY LINGER OVER THE COASTAL WATERS WELL INTO THE EVENING. MIN
TEMPS GENERALLY IN THE LOWER TO MID 70S.
SOME GUIDANCE INDICATING MUCH MORE CLOUD COVER TONIGHT THAN
CURRENTLY ADVERTISED. WE DID BUMP CLOUD COVER UP FROM THE PREVIOUS
FORECAST...BUT IT MAY NEED TO BE ADJUSTED HIGHER. THERE MAY ALSO
NOW BE A THREAT FOR SOME FOG LATER TONIGHT AND EARLY FRIDAY
MORNING WITHIN AREAS THAT RECEIVED RAIN. HOWEVER...CONFIDENCE TOO
LOW TO MENTION IN FORECAST AT THIS TIME.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
THINK FRIDAY WILL BE QUIET THROUGH MID DAY AS A WEAK AREA OF
SUBSIDENCE MOVES THROUGH. THE SUBSIDENCE MAY ALLOW FOR A LOW CLOUD
DECK FOR A FEW HOURS IN THE EARLY MORNING HOURS...GRADUALLY
BREAKING UP BY MID DAY. I HAVE GONE JUST A TOUCH BELOW MAX TEMP
GUIDANCE BASED ON THE THINKING THAT THE CLOUDS MAY KEEP TEMPS DOWN
A SMIDGE BEFORE NOON. HOWEVER...THERE SHOULD BE PLENTY OF SUNSHINE
AROUND BY AFTERNOON...WITH JUST A FEW ISOLATED THUNDERSTORMS
POSSIBLE NEAR THE SEA BREEZE.
LATER IN THE DAY...THE LEE TROF WILL GET A LITTLE BOOST FROM A WEAK
SHORTWAVE AND BE A FOCUS FOR LATE DAY CONVECTION OVER INLAND
AREAS...PROBABLY LASTING INTO THE EVENING HOURS IN A FEW PLACES.
ON SATURDAY...CLOUDS AND AFTERNOON/EVENING THUNDERSTORMS WILL
INCREASE IN COVERAGE AS A RATHER ROBUST UPPER TROF SETS UP OVER THE
EASTERN HALF OF NORTH AMERICA. THE FRONT APPROACHING FROM THE
NORTHWEST WILL STALL OVER THE UPSTATE AS A WEAK AREA OF LOW PRESSURE
FORMS ALONG THE FRONT...GIVING US MOIST AND DEEP SOUTHWESTERLY FLOW.
PWS WILL INCREASE TO NEAR 2 INCHES...AND THE CYCLONIC FLOW ALOFT
WILL PROVIDE SUPPORT FOR DIURNAL CONVECTION ALONG ANY BOUNDARIES
THAT FORM.
THINGS WILL BE EVEN MORE UNSETTLED ON SUNDAY AS THE UPPER JET
STRETCHES OUT TO OUR NORTHWEST FROM THE LOWER MISSISSIPPI VALLEY ALL
THE WAY TO NEW ENGLAND. PWS SHOULD GO UP OVER 2 INCHES BY THEN...AND
THE SYNOPTIC LIFT WILL BE STRONGER. ONLY FACTOR THAT MAY HOLD BACK
CONVECTION IN A FEW PLACES IS THE LACK OF STRONG INSTABILITY AS
CLOUDS WILL KEEP MAXIMUM TEMPS DOWN A FEW DEGREES FROM SATURDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT INDICATING AN UNSETTLED
PATTERN FOR MOST OF THE LONG TERM PERIOD WITH BROAD UPPER LEVEL
TROUGHING PERSISTING ACROSS THE EASTERN UNITED STATES THROUGH THE
MIDDLE OF NEXT WEEK. WHILE MODELS DIFFER SLIGHTLY WITH THE POSITION
OF A COLD FRONT ALONG THE SOUTHEAST COAST...THEY GENERALLY SUGGEST
THE FRONT SLOWLY SHIFTING ACROSS THE AREA ON MONDAY THEN STALLING
JUST OFFSHORE INTO THE MIDDLE OF NEXT WEEK. THE GREATEST CHANCES FOR
PRECIPITATION APPEAR TO BE EARLY IN THE WEEK WITH AN AXIS OF DEEP
MOISTURE OVER THE AREA AND THE FRONT PASSING THROUGH...BUT COULD
DIMINISH SOME TOWARD THE MIDDLE OF NEXT WEEK DEPENDING ON HOW FAR
OFFSHORE THE FRONT AND ASSOCIATED DEEP MOISTURE GET. OVERALL...THE
FORECAST WILL MAINTAIN A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH
THE LONG TERM PERIOD. SLIGHTLY BELOW NORMAL TEMPERATURES ARE
EXPECTED THROUGH THE LONG TERM PERIOD.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
CONVECTION HAS BLOSSOMED QUICKLY OVER KSAV DUE TO MULTIPLE
BOUNDARY COLLISIONS AND THE PRESENCE OF A WEAK UPPER LEVEL SHORT
WAVE. BRIEF PERIODS OF MVFR POSSIBLE THROUGH THE REST OF THE
AFTERNOON...THEN EXPECT A RETURN TO MAINLY VFR BY THIS EVENING.
CONVECTION STILL POSSIBLE AT KCHS...BUT COVERAGE EXPECTED TO BE
LESS THAN AROUND KSAV AND TIMING...IF IT OCCURS...WILL BE LATE
AFTERNOON AND EVENING. HAVE CONTINUED TO LEAVE OUT PRECIP MENTION
FOR KCHS GIVEN LOW PROBABILITIES OF IT HITTING THE TERMINAL...BUT
WILL CLOSELY MONITOR.
TONIGHT...VFR EXPECTED TO PREVAIL FOR MUCH OF THE NIGHT.
HOWEVER...STILL CONCERNED ABOUT A POTENTIAL FOR LOWER
CIGS...POSSIBLY MVFR/IFR FOR BOTH SITES MAINLY AFTER 08Z TONIGHT.
ALSO...GIVEN THE CONVECTION THIS AFTERNOON AND EVENING...FOG IS
MORE OF A POSSIBILITY...ESPECIALLY FOR KSAV. WILL NEED TO ADDRESS
THE FOG POTENTIAL WITH LATER UPDATES.
EXTENDED AVIATION OUTLOOK...THERE IS A CHANCE OF SOME LOW CLOUDS
AROUND EACH MORNING THROUGH THE WEEKEND...POSSIBLY ENOUGH TO LOWER
CIGS TO MVFR FOR AN HOUR OR TWO. OTHERWISE...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY DURING THE AFTERNOON/EVENING HOURS...COULD
RESULT IN TEMPORARY REDUCTIONS IN CIGS/VSBYS THIS WEEKEND.
&&
.MARINE...
A WEAK SURFACE FRONT REMAINS STALLED INLAND THROUGH THIS EVENING.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE ALONG
THE COASTAL WATERS THROUGH THIS EVENING. SOME OF THESE STORMS
COULD BE STRONG WITH GUSTY WINDS NEAR 35 KTS AND SMALL HAIL.
ISOLATED SHOWERS AND THUNDERSTORMS WILL GRADUALLY TAPPER OFF LATER
TONIGHT. WINDS LESS THAN 15 KTS AND SEAS 3 FT OR LESS WILL PERSIST
THROUGH TONIGHT.
AFTER A RELATIVELY QUIET FRIDAY...A COLD FRONT WILL APPROACH FROM
THE NORTHWEST THROUGH THE WEEKEND...BEFORE STALLING JUST OFF THE
SOUTHEAST COAST EARLY NEXT WEEK. OVERALL...A SOUTH-SOUTHWEST FLOW
IS GENERALLY EXPECTED EACH DAY...WITH THE FLOW VEERING OFFSHORE
DURING THE NIGHTTIME/EARLY MORNING HOURS BY NEXT WEEK. BRIEF
SURGES UPWARDS OF NO MORE THAN 15-20 KT COULD OCCUR AT TIMES...BUT
WIND AND SEA CONDITIONS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY
CRITERIA THROUGH THE PERIOD.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...RFM
SHORT TERM...ALSHEIMER
LONG TERM...JAQ
AVIATION...BDC/RFM
MARINE...ALSHEIMER/RFM
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
111 PM EDT THU AUG 16 2012
.AVIATION...
18Z TAF
REMNANT CONVECTION FROM THE MCC CONTINUES TO SHIFT EASTWARD. WAKE
PRECIPITATION SHIELD SHOWING SIGNS OF ERODING FROM THE WEST. SPEED
MAX AROUND 600MB HAS SHOWN UP ON THE PROFILER AND RADAR VWP...AS
WELL AS WATER VAPOR IMAGERY OVER SOUTHERN IA-CENTRAL IL. THIS JET
HAS BEEN THE FOCUS FOR RENEWED CONVECTIVE DEVELOPMENT IN CENTRAL
IL. EXPECT TO SEE A LINE OF CONVECTION FORMING FROM MONTICELLO
INDIANA-AUBURN INDIANA TO MONTPELIER OHIO FROM 20-22Z. INCREASED
SHEAR AND INSTABILITY WOULD FAVOR QLCS SEVERE POTENTIAL...
ESPECIALLY FOR THE KFWA TERMINAL.
CONVECTION TO MOVE QUICKLY OUT OF THE FORECAST AREA AFTER 03Z AND
SHOULD BE ENOUGH MOISTURE AND CLEARING TO SUPPORT PATCHY FOG
FORMATION BEFORE DAYBREAK.
&&
.PREV DISCUSSION... /ISSUED 633 AM EDT THU AUG 16 2012/
AVIATION...(12Z TAF ISSUANCE) COLD FRONT OVER WI-IA WILL MOVE
SOUTHEAST ACROSS NORTHERN INDIANA THIS AFTN/EVE. TSRA ALONG/AHEAD
OF THE FRONT ATTM MAY WEAKEN THIS MORNING BUT EXPECT RE-
DEVELOPMENT/INTENSIFICATION AS THE FRONT APPROACHES THE AREA THIS
AFTN. MOVED UP TIMING OF STORMS IMPACTING TERMINALS A COUPLE OF
HOURS FROM PREVIOUS TAFS BASED MAINLY ON HRRR WITH TEMPO TSRA WITH
GUSTY WINDS AND FLYING CONDITIONS LOWERING TO AT LEAST MVFR
EXPECTED AT SBN 15-19Z AND 17-21Z AT FWA. SCT SHOWERS SHOULD
PERSIST ALONG AND FOR AWHILE BEHIND THE FRONT TONIGHT WITH LOW VFR
AND PSBLY MVFR CONDITIONS.
SHORT TERM...
TODAY THROUGH FRIDAY NIGHT....THE SEVERE WEATHER POTENTIAL FOR TODAY
AND THIS EVENING IS THE MOST SIGNIFICANT CONCERN FOR THIS PERIOD. A
CONVECTIVE STORM COMPLEX ORGANIZING IN IOWA WAS BEING HELPED BY THE
UPPER LEVEL TROF AND A JET STREAK. THIS COMPLEX SHOULD MOVE ABOUT
DUE EAST AND SHOULD REACH THE FAR NORTHWEST PART OF THE FORECAST
AREA AROUND NOON EDT/16Z. A CAVEAT IS THAT OTHER CONVECTION WAS
ALREADY DEVELOPING AHEAD OF THIS COMPLEX AND COULD CAUSE SOME ISSUES
WITH BOUNDARIES...CLOUDS AND RAIN COOLED AIR. HOWEVER...SIGNIFICANT
UPPER LEVEL SUPPORT AND REASONABLE LOW LEVEL BULK SHEAR COMBINED
WITH INCREASING INSTABILITY WITH DAYTIME HEATING SHOULD BE
SUFFICIENT FOR SEVERE STORMS AS THE COMPLEX MOVES EAST. ATTEMPTED TO
PLACE SOME DETAIL IN THE GRIDS/FORECAST IN REGARD TO THE TIMING AND
COVERAGE OF STORMS. GUT FEELING IS SEVERE STORMS SHOULD BE OVER BY 8
PM EDT. OTHERWISE...MUCH COOLER AIR WILL SPREAD BACK INTO THE AREA.
WENT WITH THE WARMER MET GUIDANCE FOR HIGHS TODAY. THERE SHOULD BE A
SHALLOW RADIATION INVERSION FORM FRIDAY NIGHT...ALLOWING
TEMPERATURES TO FALL INTO THE UPPER 40S TO AROUND 50 DEGREES MOST
AREAS. HAVE LOWERED LOWS SEVERAL DEGREES IN THIS REGARD.
LONG TERM.../SAT-WED/
DEEP VERTICALLY STACKED LOW OVER JAMES BAY AT START OF THE
PERIOD IS EXPECTED TO SLOWLY LIFT NE AND FILL/WEAKEN OVER THE
WEEKEND. WK SHRTWV ROTATING AROUND THE LOW EXPECTED TO MOVE ACROSS
THE WRN GRTLKS SAT NGT/SUNDAY. DRY AIRMASS WILL BE IN PLACE OVER OUR
AREA... BUT THERE MAY BE SUFFICIENT MOISTURE/INSTABILITY FOR
ISOLATED SHOWERS OVER/NEAR LM SAT NGT AND WITH AID OF DIURNAL
HEATING... ACROSS NRN 1/2 OF CWA SUNDAY. COOL POOL ASSOCIATED WITH
THE UPR TROF WILL RESULT IN CONTD BLO NORMAL TEMPS OVER THE WEEKEND
WITH HIGHS IN THE L-M70S AND LOWS IN THE L-M50S. FAIR WX WITH A SLOW
WARMING TREND EXPECTED MON-TUE AS HEIGHTS RISE IN RESPONSE TO WKNG
ERN CANADA/GRTLKS UPR TROF. SHRTWV MOVG INTO PAC NW BY WED WILL
CAUSE WRN U.S. RIDGE TO MOVE EAST INTO THE PLAINS CONTG DRY SPELL
AND GRADUAL WARMING TREND IN OUR AREA.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...RIP CURRENT RISK THROUGH FRIDAY EVENING FOR INZ003.
MI...RIP CURRENT RISK THROUGH FRIDAY EVENING FOR MIZ077.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT FRIDAY FOR LMZ043-046.
&&
$$
SHORT TERM...SKIPPER
LONG TERM...JT
AVIATION...LEWIS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
356 PM MDT THU AUG 16 2012
.UPDATE...
ISSUED AT 356 PM MDT THU AUG 16 2012
JUST COMPLETED MINOR UPDATE TO CAPTURE LATEST TREND REGARDING
POPS/SKY OVER WESTERN PARTS OF CWA. ACTIVITY OVER FRONT RANGE
CURRENTLY PROGRESSING EASTWARD TOWARDS WESTERN EXTENT OF CWA.
BASED ON LATEST RUC INSTABILITY REMAINS VERY WEAK OVER OUR CWA
AND THERE IS LITTLE IN THE WAY OF LARGE SCALE ASCENT. JUST BASED
ON CURRENT RADAR TRENDS AND RUC QPF I COULDNT RULE OUT AN ISOLATED
SHOWER OR THUNDERSTORM SNEAKING INTO WESTERN YUMA AND KIT CARSON
COUNTIES LATE THIS AFTERNOON OR EARLY THIS EVENING BEFORE DIURNAL
HEATING COMES TO AN END AND LOW LEVEL LAPSE RATES DECREASE. NO
OTHER SIGNIFICANT CHANGE MADE.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 210 PM MDT THU AUG 16 2012
18Z WATER VAPOR IMAGERY INDICATED AN UPPER LEVEL SHORT WAVE TROUGH
OVER THE NORTH CENTRAL CONUS...WITH THE TROUGH AXIS EXTENDING
SOUTHWEST INTO WESTERN KANSAS. AT THE SURFACE HIGH PRESSURE WAS
OVER THE NEBRASKA PANHANDLE...BUILDING SOUTHEAST. THE COLD FRONT WAS
BACKED UP AGAINST THE ROCKIES AND EXTENDED SOUTHEAST INTO THE TEXAS
PANHANDLE.
TONIGHT WINDS WILL BE LIGHT AS THE HIGH PRESSURE BUILDS INTO THE
AREA. DURING THE OVERNIGHT HOURS THE SURFACE HIGH MOVES EAST OF THE
AREA. MEANWHILE WARM AIR ADVECTION IN THE 750-650 MB LAYER AND
MOISTURE INCREASE OVER THE EASTERN PART OF THE AREA BEHIND THE
SURFACE HIGH. A DRY LAYER WILL REMAIN IN PLACE BELOW 750MB SO WILL
KEEP THE PRECIPITATION CHANCES IN THE SLIGHT CATEGORY.
EARLY FRIDAY MORNING WARM AIR ADVECTION INCREASES AND AN UPPER LEVEL
SHORT WAVE TROUGH MOVES OVER THE EASTERN HALF OF THE AREA.
INCREASED PRECIP. CHANCES DURING THE FIRST HALF OF THE MORNING WHEN
THE LIFT AND MOISTURE WILL BE GREATEST. DURING THE LATE MORNING AND
AFTERNOON THE BETTER ISENTROPIC LIFT/MOISTURE MOVE EAST WITH THE
SHORT WAVE TROUGH...BRINGING PRECIPITATION CHANCES TO AN END FROM WEST
TO EAST. DURING THE LATE AFTERNOON SURFACE CONVERGENCE/LIFT FROM A
700MB SHORT WAVE TROUGH DEVELOP OVER LINCOLN COUNTY CO. POINT
SOUNDINGS SHOW THE AIR MASS EITHER BEING TOO DRY OR CAPPED. HOWEVER
AS THE SURFACE HIGH MOVES EAST IT WILL DRAG THE FRONT ACROSS THE
WEST HALF OF AREA WITH IT. WILL INCLUDE LOW SLIGHT CHANCES OVER THE
FAR WEST DURING THE LATE AFTERNOON DUE TO THE SHORT WAVE AND FRONT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 210 PM MDT THU AUG 16 2012
NORTHWEST FLOW WILL CONTINUE THROUGH SUNDAY WITH A RIDGE OVER THE
ROCKIES AND AN UPPER LOW NORTH OF THE GREAT LAKES. SURFACE HIGH
PRESSURE WILL RESIDE OVER THE CENTRAL PLAINS THROUGH THIS TIME.
A SHORTWAVE COMES THROUGH THE FLOW FRIDAY NIGHT/EARLY SATURDAY. THE
BEST FORCING COMES ACROSS THE FA FRIDAY NIGHT WITH DYNAMICS EXITING
ALL BUT THE EASTERN FA SATURDAY MORNING. SUBSIDENCE MOVES INTO THE
FA SATURDAY AFTERNOON/NIGHT. SUBSIDENCE CONTINUES SUNDAY. 850-700
LAYER MEAN RH IS LIMITED WITH THE BEST MOISTURE JUST TO THE EAST OF
THE FA. DUE TO THE LIMITED MOISTURE WILL GO WITH SLIGHT CHANCE POPS
FRIDAY NIGHT/EARLY SATURDAY WITH NIL POPS SATURDAY AFTERNOON/NIGHT
THROUGH SUNDAY.
MIN TEMPERATURES WILL BE IN THE MID 50S FRIDAY NIGHT AND THE LOWER
TO MID 50S SATURDAY NIGHT. MAX TEMPERATURES WILL RISE TO THE LOWER
80S SATURDAY/SUNDAY.
FOR SUNDAY NIGHT THROUGH THURSDAY...A RIDGE WILL BE OVER THE ROCKIES
THROUGH THURSDAY. OTHER THAN SURFACE HIGH PRESSURE SUNDAY, A TROUGH
WILL EXIST OVER EASTERN COLORADO THROUGH THURSDAY.
SHORTWAVES IN THE FLOW WILL BRING A SLIGHT CHANCE OF THUNDERSTORMS
MONDAY THROUGH TUESDAY NIGHT. DYNAMICS MOVE OFF TO THE NORTHEAST
WEDNESDAY WITH SUBSIDENCE FOLLOWING WEDNESDAY NIGHT/THURSDAY.
850 TEMPERATURES INDICATE STEADILY WARMER TEMPERATURES WITH MAX
TEMPERATURES IN THE MID 80S MONDAY WARMING TO THE LOWER 90S
WEDNESDAY COOLING SLIGHTLY TO THE UPPER 80S THURSDAY. MIN
TEMPERATURES WILL RANGE FROM THE LOWER 60S TO THE MID 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1107 AM MDT THU AUG 16 2012
VFR CONDITIONS FORECAST FOR THE 18Z TAFS. SURFACE HIGH PRESSURE
OVER WESTERN NEBRASKA WILL CONTINUE TO BUILD SOUTHEAST TODAY
THROUGH FRIDAY. SPOTTY SPRINKLES MAY STILL DEVELOP NEAR/OVER KMCK
THROUGH THE EARLY AFTERNOON AHEAD OF THE SURFACE HIGH...BUT AM NOT
ANTICIPATING ANY RESTRICTIONS WITH THEM. OTHERWISE PRECIPITATION
CHANCES WILL INCREASE OVERNIGHT THROUGH FRIDAY MORNING...MAINLY
EAST OF KGLD. AM ANTICIPATING MOSTLY RAIN SHOWERS WITH ISOLATED
THUNDERSTORMS...MAINLY DURING THE MORNING. DECIDED AGAINST ADDING
A MENTION OF VCSH TO KMCK AT THIS TIME SINCE THERE IS TOO MUCH
UNCERTAINTY WITH SHOWERS DEVELOPING NEAR/OVER KMCK AT THIS TIME.
WINDS WILL INCREASE FOR KGLD DURING THE MORNING AS THE SURFACE
HIGH PRESSURE MOVES EAST AND THE PRESSURE GRADIENT TIGHTENS BEHIND
IT. ANTICIPATE THE WINDS TO DECLINE DURING THE AFTERNOON.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...DR
SHORT TERM...FS
LONG TERM...JTL
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1217 PM CDT THU AUG 16 2012
.UPDATE...
ISSUED AT 1215 PM CDT THU AUG 16 2012
QUICK UPDATE TO THE GRIDS TO ACCOUNT FOR LATEST KDDC WSR-88D
TRENDS. SCATTERED SPRINKLES WILL BE LIKELY THIS AFTERNOON ACROSS
THE NORTHWESTERN AND NORTHERN ZONES. THE HRRR HAS LATCHED ON ACTIVITY
APPROPRIATELY.
&&
.SYNOPSIS...
ISSUED AT 911 AM CDT THU AUG 16 2012
THE 16.12Z 250 HPA SYNOPTIC MAP SHOWED AN 80-85 KT JET STREAK MOVING
ACROSS SOUTH DAKOTA AND INTO MINNESOTA. ANOTHER 80-85 KT JET STREAK
WAS LOCATED ACROSS NEW ENGLAND. AT 500 HPA, A SHORTWAVE TROF WAS LOCATED
FROM ONTARIO SOUTHWARD TO NEBRASKA. MID LEVEL COLD AIR ADVECTION WAS
OCCURRING IN THE WAKE OF THE TROF ACROSS THE NORTHERN PLAINS. ANOTHER
ELONGATED SHORTWAVE TROF WAS LOCATED ACROSS THE NORTHEAST US. AT 700
HPA, LOW TO MID LEVEL TEMPERATURES WERE STILL WARM ACROSS SW KANSAS
WITH KDDC MEASURING 13 DEG C. THIS WAS PROBABLY THE REASON FOR A LACK
OF CONVECTION ALONG A FRONT THAT MOVED THROUGH. ALL THE COLD AIR WITH
700 HPA TEMPERATURES BELOW 5 DEG C WAS LOCATED ACROSS THE DAKOTAS AND
NORTHWARD. AT 850 HPA, A BAROCLINIC ZONE WAS BISECTING KANSAS SEPARATING
20S DEG C AIR FROM LOWER TEENS DEG C. VALUES AS LOW AS 6 DEG C WERE
OBSERVED ACROSS THE DAKOTAS AND MONTANA. KDDC WAS MUCH COOLER THAN 12
HOURS AGO (18 DEG C VERSUS 27 DEG C). AT THE SURFACE, A 995 HPA CYCLONE
WAS LOCATED ACROSS WESTERN ONTARIO WITH A COLD FRONT FROM THIS SYSTEM
SOUTHWEST TO THE TEXAS PANHANDLE. A 1025 HPA HIGH LOCATED ACROSS THE
LEE OF THE NORTHERN ROCKIES WAS MOVING SOUTHWARD IN THE WAKE OF THE
SURFACE FRONT.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 355 AM CDT THU AUG 16 2012
A STRONG SHORTWAVE TROUGH MOVING ACROSS THE NORTHERN PLAINS EARLY
THIS MORNING WILL PUSH A COLD FRONT INTO OKLAHOMA BY THIS AFTERNOON.
WITH THE LOSS OF DAYTIME HEATING, SURFACE BASED THUNDERSTORMS HAD
DISSIPATED ACROSS NORTHERN KANSAS EARLIER TONIGHT. MODEL SOUNDINGS
FOR SOUTH CENTRAL KANSAS FOR EARLY THIS MORNING SHOW STRONG CAPPING
AHEAD OF THE FRONT. SURFACE BASED CONVECTION SEEMS HIGHLY UNLIKELY,
ESPECIALLY GIVEN THE INITIALLY SHALLOW NATURE OF THE LOW LEVEL FRONT
AS IT ENCOUNTERS THE 60-65F DEWPOINTS AS WELL AS THE TIME OF DAY.
ALSO, WITH THE MAIN UPPER-LEVEL JET STREAK WELL TO THE NORTH AND
ANOTHER MINOR JET STREAK WELL TO OUR SOUTH, DEEP, LARGE SCALE LIFT
IS ABSENT. SO WE ARE EXPECTING A DRY FRONTAL PASSAGE, WITH ONLY
SCATTERED TO BROKEN MID TO HIGH LEVEL CLOUDS. WINDS WILL BE FROM THE
NORTH TO NORTHEAST AT 20-25 KTS FROM 15-18Z BEFORE DIMINISHING TO 15
KTS LATER THIS AFTERNOON AS THE PRESSURE GRADIENT RELAXES. I DECIDED
TO UNDERCUT THE NAM TEMPERATURES FOR TODAY JUST SLIGHTLY SINCE THE
FRONT IS AHEAD OF SCHEDULE WITH STRONG COLD ADVECTION IN ITS WAKE.
IF POST FRONTAL CLOUD COVER IS MORE EXTENSIVE THAN FORE CAST THEN
IT COULD STAY EVEN COOLER. BUT I SEE NO REASON WHY MID-LEVEL CLOUD
WOULD STAY ABUNDANT ALL DAY.
BY LATE TONIGHT, THE AFOREMENTIONED SHORTWAVE TROUGH WILL HAVE
PASSED INTO THE GREAT LAKES REGION, WITH WESTERN KANSAS IN THE RIGHT
ENTRANCE REGION OF THE ASSOCIATED JET STREAK, ALONG WITH SOME MID
LEVEL FRONTOGENESIS. A FEW SHOWERS AND THUNDERSTORMS MAY DEVELOP
TOWARD MORNING, WITH THE BEST CHANCES IN CENTRAL KANSAS. ALTHOUGH
TEMPERATURES SHOULD BE RATHER COOL, CLOUD COVER AND 5 TO 7 KT WINDS
COULD PREVENT TEMPERATURES FROM REALLY BOTTOMING OUT. HOWEVER, IF
THE CLEAR BREAKS ARE SIGNIFICANT, THEN TEMPERATURES COULD FALL INTO
THE LOWER OR MIDDLE 50S. MINIMUM TEMPERATURES COULD ACTUALLY BE LOWER IN
PLACES LIKE ULYSSES AND ELKHART THAN HAYS SINCE CLOUD COVER MAY BE
MORE ABUNDANT IN CENTRAL KANSAS THAN THE FAR SOUTHWEST.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 355 AM CDT THU AUG 16 2012
N UPPER LEVEL TROUGH WILL MOVE EAST ACROSS THE GREAT LAKES REGION
ON FRIDAY AS AN AREA OF HIGH PRESSURE AT THE SURFACE SETTLES INTO
THE CENTRAL PLAINS. BASED ON THE COOLING FORECAST IN THE 925-850MB
LEVEL BY FRIDAY AFTERNOON THE PREVIOUS FORECAST STILL LOOKS ON
TRACK. DID HOWEVER LOWER TEMPERATURES BACK INTO THE UPPER 70S IN
NORTH CENTRAL AND IN PARTS OF WEST CENTRAL KANSAS GIVEN THE LATEST
NAM AND ECMWF 850MB TEMPERATURES AND PROBABILITY OF INCREASING CLOUD
COVER.
CLOUD COVER IS EXPECTED TO INCREASE ACROSS SOUTHWEST KANSAS ON
FRIDAY AS 850-700MB WINDS VEER AND WARM AIR ADVECTION DEVELOPS.
I310-I315 ISENTROPIC LIFT ALSO WILL BE IMPROVING LATE FRIDAY AND
WILL THEN CONTINUE ACROSS WESTERN KANSAS THROUGH SATURDAY. IN
ADDITION AN UPPER LEVEL TROUGH IS FORECAST TO CROSS THE CENTRAL
PLAINS EARLY THIS WEEKEND AS AN UPPER LEVEL JET CROSSES THE PLAINS.
GIVEN THIS ALONG WITH THE LOCATION OF THE RIGHT ENTRANCE REGION OF
THE UPPER LEVEL JET WILL FAVOR KEEPING THE BETTER CHANCES FOR
PRECIPITATION EARLY SATURDAY. THE PRECIPITATION CHANCES WILL THEN
BEGIN TO TAPER OFF EARLY SATURDAY NIGHT FROM NORTH TO SOUTH AS THIS
UPPER WAVE/JET PASSES.
SUNDAY STILL APPEARS TO BE DRY WHILE ANOTHER UPPER LEVEL TROUGH IS
FORECAST BY BOTH THE ECMWF AND GFS TO MOVE OUT OF THE ROCKIES AND
ACROSS THE CENTRAL PLAINS LATE MONDAY/EARLY TUESDAY. AS FOR
TEMPERATURES SUNDAY AND MONDAY A SLOW WARMING TREND IS EXPECTED BUT
HIGHS STILL APPEAR TO BE MAINLY IN THE 80S GIVEN 850MB TEMPERATURES
AT 00Z MONDAY AND 00Z TUESDAY GENERALLY RANGING FROM 20C TO 23C.
A TROUGH OF LOW PRESSURE AT THE SURFACE WILL DEVELOP ALONG THE LEE
OF THE ROCKIES EARLY NEXT WEEK AS WARMER 850-700MB TEMPERATURES
BEGIN TO SPREAD EAST ACROSS EASTERN COLORADO/WESTERN KANSAS. THE GFS
ATTEMPTS TO DEVELOP SOME OVERNIGHT CONVECTION MID WEEK ACROSS
PORTIONS OF WESTERN AND SOUTH CENTRAL KANSAS JUST EAST OF THE WARM
(+10 TO +12C) 700MB TEMPERATURES WHERE SOME 850MB WARM AIR ADVECTION
DEVELOPS. UPPER LEVEL DYNAMICS APPEAR SOMEWHAT LACKING TOWARDS MID
WEEK AS DOES THE 850-700MB MOISTURE BUT AT THIS TIME CONFIDENCE IS
NOT HIGH ENOUGH YET TO REMOVE MENTION OF PRECIPITATION MID WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1200 PM CDT THU AUG 16 2012
VFR CIGS EXPECTED THROUGH PD. NORTHEASTERLY WINDS AROUND 20 KT
WILL DECREASE 10 TO 15 KT BY THIS EVENING AND CONTINUE TO VEER
THROUGH THE OVERNIGHT. THETA-E ADVECTION/WARM AIR ADVECTION/ISENTROPIC
LIFT WILL LEAD TO CONVECTION ACROSS CENTRAL KANSAS TOMORROW
MORNING. HAVE INSERTED CB/TS GROUPS AS A RESULT FOR KHYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 84 56 80 59 / 10 20 20 30
GCK 82 55 80 58 / 10 10 20 20
EHA 84 57 83 61 / 10 10 20 20
LBL 86 57 83 60 / 10 10 20 30
HYS 81 57 79 59 / 10 20 20 30
P28 87 59 82 62 / 10 20 20 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SUGDEN
SYNOPSIS...SUGDEN
SHORT TERM...FINCH
LONG TERM...BURGERT
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
508 PM EDT THU AUG 16 2012
.SYNOPSIS...
DRY WEATHER WILL COME TO AN END TONIGHT AS A COLD FRONT APPROACHES
FROM THE WEST. THE COLD FRONT WILL CROSS THE AREA EARLY FRIDAY,
BRINGING SHOWERS AND THUNDERSTORMS TO THE REGION. IN THE WAKE OF
THE FRONT, A COOLER AND DRIER WEEKEND CAN BE EXPECTED.
&&
.NEAR TERM /THROUGH FRIDAY/...
QUICK UPDATE TO ADD SLIGHT CHANCE TO COUNTIES NORTH AND EAST OF
PITTSBURGH AS RANDOM SHOWERS AND STORMS HAVE DEVELOPED WELL AHEAD
OF MAIN ACTIVITY. NO OTHER CHANGES AND PREVIOUS DISCUSSION
FOLLOWS.
AT THE SURFACE, A COLD FRONT EXTENDS SOUTHWARD FROM A SURFACE LOW
THAT IS CENTERED NORTH OF LAKE SUPERIOR. THE FRONT EXTENDS ACROSS
LAKE MICHIGAN AND INTO ILLINOIS. WELL AHEAD OF THIS FEATURE, A
1018MB SURFACE HIGH CENTERED ACROSS WEST VIRGINIA CONTINUES TO
ALLOW FOR MAINLY DRY WEATHER ACROSS THE UPPER OHIO VALLEY.
THIS EVENING..RIDGE AXIS WILL SHIFT EASTWARD AS A SURFACE TROUGH
AND ITS COINCIDENT COLD FRONT APPROACH FROM THE WEST. UPSTREAM
QUASI-LINEAR CONVECTIVE SYSTEM (QLCS) IS ANTICIPATED TO SLIDE
SOUTHEASTWARD AND DIMINISH MOSTLY BEFORE REACHING THE UPPER OHIO
VALLEY. THE RAP INDICATES SBCAPE INCREASING TO AROUND 1500 J/KG
WITH LI VALUES DECREASING TO -1 TO -3 BY LATE EVENING. THIS MAY BE
ENOUGH INSTABILITY TO INSTIGATE A FEW SHOWERS OR STORMS AS
DIMINISHING CONVECTION CROSSES OHIO. THUS, A SCHC IS FORECAST FOR
AREAS NORTHWEST OF PITTSBURGH. FOCUS OF THUNDERSTORMS TO IMPACT
OUR AREA TONIGHT WILL THEN SHIFT TO RIGHT ALONG THE FRONT.
TONIGHT...THE COLD FRONT AND SURFACE TROUGH ARE PROGGED TO MOVE
ACROSS OHIO OVERNIGHT, ENTERING WESTERN PA BY AROUND 12Z ON FRIDAY.
INITIAL QLCS WILL WEAKEN AND THE FOCUS OF CONVECTION SHOULD HAVE
TRANSITIONED CLOSER TO THE ACTUAL FRONT. A MODEL CONSENSUS INDICATES
THAT INSTABILITY WILL BE WEAK OVERNIGHT WITH SBCAPE AND MUCAPE
VALUES LESS THAN 500 J/KG AS THE FRONT CROSSES OHIO. WITH WEAK
SHEAR OVERNIGHT, DO NOT ANTICIPATE A SEVERE THREAT. HOWEVER, THERE
STILL MAY BE ENOUGH LIFT AND MOISTURE TO SUPPORT THUNDERSTORMS AS
THE FRONT MOVES ACROSS. WITH INCREASING LOW-LEVEL MOISTURE,
OVERNIGHT LOWS WILL BE LIMITED TO THE MID TO UPPER 60S ACROSS MOST
OF THE AREA.
FRIDAY...THERE IS MODEL AGREEMENT BETWEEN THE GFS/NAM THAT THE FRONT
AXIS IS PROGGED TO BE ALONG THE RIDGES BY BETWEEN 18Z AND 21Z FRI, AND
AM LEANING TOWARDS THE EARLIER SOLUTION GIVEN UPSTREAM PROGRESSION
OF THE FRONT THUS FAR. THUS, GIVEN THE EARLY PASSAGE OF THE FRONT
AND LIMITED INSTABILITY, BELIEVE IT WILL PASS MOST OF THE AREA AT A
DIURNALLY UNFAVORABLE TIME FOR SEVERE WEATHER. THE SOUTHEASTERN
RIDGES OF WV/MD HAVE THE BEST CHANCE OF A STRONG THUNDERSTORM AS
THE LINE RE-DEVELOPS IN THE LATE MORNING, BUT THE SEVERE THREAT
THERE IS STILL MINIMAL WITH WEAK SHEAR AND THE BEST INSTABILITY
SOUTHEAST OF THE APPALACHIANS. CATEGORICAL POPS ARE FORECAST ALONG
THE FRONT, WITH GENERALLY A QUARTER TO A HALF OF AN INCH OF
RAINFALL ANTICIPATED WITH ITS PASSAGE.
THERE IS SOME UNCERTAINTY WITH HIGH TEMPS ON FRIDAY DEPENDING ON THE
TIMING OF THE FRONT. HIGHS ARE CLOSEST TO THE ECMWF IN THE LOWER TO
MID 70S, WITH LITTLE DIURNAL RANGE FOR MUCH OF THE AREA AS WEAK COLD
AIR ADVECTION BEGINS TO WORK FROM THE NORTHWEST BEHIND THE FRONT.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
THERE IS GFS/NAM/ECMWF AGREEMENT THAT IN THE WAKE OF THE FRONT A
COOLER AND DRIER AIR MASS WILL BE USHERED INTO THE AREA ON FRIDAY
NIGHT WITH A SURFACE HIGH BUILDING INTO THE OHIO VALLEY. THIS WILL
ALLOW FOR A MOSTLY DRY WEEKEND WITH TEMPS 5 TO 10 DEGREES BELOW
NORMAL.
THE ONE PIECE OF UNCERTAINTY IN THE DRY FORECAST OVER THE WEEKEND IS
A WAVE THAT WILL SWING AROUND THE BASE OF A LONG WAVE TROUGH
CENTERED ACROSS THE GREAT LAKES. THE WAVE WILL MOVE NORTHEAST ALONG
THE APPALACHIANS ON SUNDAY. SCHC SHOWERS ARE FORECAST WITH THIS
FEATURE ACROSS THE SOUTHEASTERN RIDGES GIVEN THE UNCERTAINTY OF
ITS WESTERN EXTENT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
KEPT MENTION OF ISOLATED SHOWERS ALONG THE RIDGES SUNDAY NIGHT INTO
MONDAY AS AN UPPER TROUGH REMAINS OVER THE GREAT LAKES REGION WHILE
A WEAK SURFACE LOW CROSSES THE SOUTHEASTERN STATES. THE REMAINDER OF
THE EXTENDED PERIOD SHOULD BE DRY AS A SURFACE RIDGE BUILDS EASTWARD
ACROSS THE UPPER OHIO VALLEY.
TEMPERATURES ARE FORECAST TO BE 5 TO 10 DEGREES BELOW NORMAL THROUGH
TUESDAY...THEN RETURN TO NEAR NORMAL BY MIDWEEK.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
A LOW PRESSURE SYSTEM CROSSING SOUTHERN ONTARIO WILL PUSH A COLD
FRONT EASTWARD ACROSS THE TERMINALS FRIDAY MORNING. EXPECT VFR
CONDITIONS TO CONTINUE THROUGH THIS EVENING AS BROKEN MID LEVEL
CLOUD DECK AHEAD OF THE FRONT SPREADS ACROSS THE OHIO VALLEY. A BAND
OF RAIN SHOWERS AND EMBEDDED THUNDERSTORMS JUST AHEAD OF AND ALONG
FRONTAL BOUNDARY IS FORECAST TO REACH KZZV BY AROUND 05Z AND WESTERN
PA SITES BY 09Z-12Z FRIDAY. MVFR RESTRICTIONS SHOULD PREVAIL WITH
BRIEF IFR CONDITIONS POSSIBLE IN HEAVIER RAINFALL WITH
THUNDERSTORMS. PRECIPITATION AND RESTRICTIONS SHOULD END BY
18Z-21Z AS SYSTEM PULLS EAST OF THE REGION.
.OUTLOOK/ FRIDAY NIGHT THROUGH TUESDAY/...
GENERALLY VFR WEATHER IS ANTICIPATED UNDER A WEAK SURFACE RIDGE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
356 PM EDT THU AUG 16 2012
.SYNOPSIS...
DRY WEATHER WILL COME TO AN END TONIGHT AS A COLD FRONT APPROACHES
FROM THE WEST. THE COLD FRONT WILL CROSS THE AREA EARLY ON FRIDAY,
BRINGING SHOWERS AND THUNDERSTORMS TO THE REGION. IN THE WAKE OF THE
FRONT, A COOLER AND DRIER WEEKEND CAN BE EXPECTED.
&&
.NEAR TERM /THROUGH FRIDAY/...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A WEAK 500MB RIDGE AXIS
EXTENDING FROM WESTERN PA INTO EASTERN ONTARIO. DRY MID-LEVELS
ACROSS THE REGION ARE GIVING WAY TO UPSTREAM MOISTURE AS IT
SPILLS AHEAD OF CONVECTION THAT HAS DEVELOPED IN ADVANCE OF A COLD
FRONT. AT THE SURFACE, THE AFOREMENTIONED COLD FRONT EXTENDS
SOUTHWARD FROM A SURFACE LOW THAT IS CENTERED NORTH OF LAKE
SUPERIOR. THE FRONT EXTENDS ACROSS LAKE MICHIGAN AND INTO
ILLINOIS. WELL AHEAD OF THIS FEATURE, A 1018MB SURFACE HIGH
CENTERED ACROSS WEST VIRGINIA CONTINUES TO ALLOW FOR DRY WEATHER
ACROSS THE UPPER OHIO VALLEY.
THIS EVENING..THE RIDGE AXIS WILL SHIFT EASTWARD AS A SURFACE
TROUGH AND ITS COINCIDENT COLD FRONT APPROACH FROM THE WEST.
UPSTREAM QUASI-LINEAR CONVECTIVE SYSTEM (QLCS) IS ANTICIPATED TO
SLIDE SOUTHEASTWARD AND DIMINISH MOSTLY BEFORE REACHING THE UPPER
OHIO VALLEY. THE RAP INDICATES SBCAPE INCREASING TO AROUND 1500
J/KG WITH LI VALUES DECREASING TO -1 TO -3 BY LATE EVENING. THIS
MAY BE ENOUGH INSTABILITY TO INSTIGATE A FEW SHOWERS OR STORMS AS
DIMINISHING CONVECTION CROSSES OHIO. THUS, A SCHC IS FORECAST FOR
AREAS NORTHWEST OF PITTSBURGH. FOCUS OF THUNDERSTORMS TO IMPACT
OUR AREA TONIGHT WILL THEN SHIFT TO RIGHT ALONG THE FRONT.
TONIGHT...THE COLD FRONT AND SURFACE TROUGH ARE PROGGED TO MOVE
ACROSS OHIO OVERNIGHT, ENTERING WESTERN PA BY AROUND 12Z ON FRIDAY.
INITIAL QLCS WILL WEAKEN AND THE FOCUS OF CONVECTION SHOULD HAVE
TRANSITIONED CLOSER TO THE ACTUAL FRONT. A MODEL CONSENSUS INDICATES
THAT INSTABILITY WILL BE WEAK OVERNIGHT WITH SBCAPE AND MUCAPE
VALUES LESS THAN 500 J/KG AS THE FRONT CROSSES OHIO. WITH WEAK
SHEAR OVERNIGHT, DO NOT ANTICIPATE A SEVERE THREAT. HOWEVER, THERE
STILL MAY BE ENOUGH LIFT AND MOISTURE TO SUPPORT THUNDERSTORMS AS
THE FRONT MOVES ACROSS. WITH INCREASING LOW-LEVEL MOISTURE,
OVERNIGHT LOWS WILL BE LIMITED TO THE MID TO UPPER 60S ACROSS MOST
OF THE AREA.
FRIDAY...THERE IS MODEL AGREEMENT BETWEEN THE GFS/NAM THAT THE FRONT
AXIS IS PROGGED TO BE ALONG THE RIDGES BY BETWEEN 18Z AND 21Z FRI, AND
AM LEANING TOWARDS THE EARLIER SOLUTION GIVEN UPSTREAM PROGRESSION
OF THE FRONT THUS FAR. THUS, GIVEN THE EARLY PASSAGE OF THE FRONT
AND LIMITED INSTABILITY, BELIEVE IT WILL PASS MOST OF THE AREA AT A
DIURNALLY UNFAVORABLE TIME FOR SEVERE WEATHER. THE SOUTHEASTERN
RIDGES OF WV/MD HAVE THE BEST CHANCE OF A STRONG THUNDERSTORM AS
THE LINE RE-DEVELOPS IN THE LATE MORNING, BUT THE SEVERE THREAT
THERE IS STILL MINIMAL WITH WEAK SHEAR AND THE BEST INSTABILITY
SOUTHEAST OF THE APPALACHIANS. CATEGORICAL POPS ARE FORECAST ALONG
THE FRONT, WITH GENERALLY A QUARTER TO A HALF OF AN INCH OF
RAINFALL ANTICIPATED WITH ITS PASSAGE.
THERE IS SOME UNCERTAINTY WITH HIGH TEMPS ON FRIDAY DEPENDING ON THE
TIMING OF THE FRONT. HIGHS ARE CLOSEST TO THE ECMWF IN THE LOWER TO
MID 70S, WITH LITTLE DIURNAL RANGE FOR MUCH OF THE AREA AS WEAK COLD
AIR ADVECTION BEGINS TO WORK FROM THE NORTHWEST BEHIND THE FRONT.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
THERE IS GFS/NAM/ECMWF AGREEMENT THAT IN THE WAKE OF THE FRONT A
COOLER AND DRIER AIR MASS WILL BE USHERED INTO THE AREA ON FRIDAY
NIGHT WITH A SURFACE HIGH BUILDING INTO THE OHIO VALLEY. THIS WILL
ALLOW FOR A MOSTLY DRY WEEKEND WITH TEMPS 5 TO 10 DEGREES BELOW
NORMAL.
THE ONE PIECE OF UNCERTAINTY IN THE DRY FORECAST OVER THE WEEKEND IS
A WAVE THAT WILL SWING AROUND THE BASE OF A LONG WAVE TROUGH
CENTERED ACROSS THE GREAT LAKES. THE WAVE WILL MOVE NORTHEAST ALONG
THE APPALACHIANS ON SUNDAY. SCHC SHOWERS ARE FORECAST WITH THIS
FEATURE ACROSS THE SOUTHEASTERN RIDGES GIVEN THE UNCERTAINTY OF
ITS WESTERN EXTENT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
KEPT MENTION OF ISOLATED SHOWERS ALONG THE RIDGES SUNDAY NIGHT INTO
MONDAY AS AN UPPER TROUGH REMAINS OVER THE GREAT LAKES REGION WHILE
A WEAK SURFACE LOW CROSSES THE SOUTHEASTERN STATES. THE REMAINDER OF
THE EXTENDED PERIOD SHOULD BE DRY AS A SURFACE RIDGE BUILDS EASTWARD
ACROSS THE UPPER OHIO VALLEY.
TEMPERATURES ARE FORECAST TO BE 5 TO 10 DEGREES BELOW NORMAL THROUGH
TUESDAY...THEN RETURN TO NEAR NORMAL BY MIDWEEK.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
A LOW PRESSURE SYSTEM CROSSING SOUTHERN ONTARIO WILL PUSH A COLD
FRONT EASTWARD ACROSS THE TERMINALS FRIDAY MORNING. EXPECT VFR
CONDITIONS TO CONTINUE THROUGH THIS EVENING AS BROKEN MID LEVEL
CLOUD DECK AHEAD OF THE FRONT SPREADS ACROSS THE OHIO VALLEY. A BAND
OF RAIN SHOWERS AND EMBEDDED THUNDERSTORMS JUST AHEAD OF AND ALONG
FRONTAL BOUNDARY IS FORECAST TO REACH KZZV BY AROUND 05Z AND WESTERN
PA SITES BY 09Z-12Z FRIDAY. MVFR RESTRICTIONS SHOULD PREVAIL WITH
BRIEF IFR CONDITIONS POSSIBLE IN HEAVIER RAINFALL WITH
THUNDERSTORMS. PRECIPITATION AND RESTRICTIONS SHOULD END BY
18Z-21Z AS SYSTEM PULLS EAST OF THE REGION.
.OUTLOOK/ FRIDAY NIGHT THROUGH TUESDAY/...
GENERALLY VFR WEATHER IS ANTICIPATED UNDER A WEAK SURFACE RIDGE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1201 PM EDT THU AUG 16 2012
.SYNOPSIS...
DRY WEATHER WILL COME TO AN END TONIGHT AS A COLD FRONT APPROACHES
FROM THE WEST. THE COLD FRONT WILL CROSS THE AREA EARLY ON FRIDAY,
BRINGING SHOWERS AND THUNDERSTORMS TO THE REGION. IN THE WAKE OF THE
FRONT, A COOLER AND DRIER WEEKEND CAN BE EXPECTED.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AN ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO MAKE THE
ONSET OF THE CHANCE OF SHOWERS AND THUNDERSTORMS EARLIER TONIGHT.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A WEAK 500MB RIDGE AXIS
EXTENDING FROM THE OHIO VALLEY INTO EASTERN ONTARIO. DRY MID-LEVELS
ACROSS THE REGION ARE ABOUT TO GIVE WAY TO UPSTREAM MOISTURE AS IT
SPILLS AHEAD OF THE MCS DEVELOPING WITH A COLD FRONT. AT THE
SURFACE, THE AFOREMENTIONED COLD FRONT EXTENDS SOUTHWARD FROM A
SURFACE LOW THAT IS CENTERED NORTH OF LAKE SUPERIOR. THE FRONT
EXTENDS ACROSS THE UPPER MIDWEST AND INTO MISSOURI. WELL AHEAD OF
THIS FEATURE, A 1019MB SURFACE HIGH CENTERED ACROSS WEST VIRGINIA
CONTINUES TO ALLOW FOR DRY WEATHER ACROSS THE UPPER OHIO VALLEY.
THIS AFTERNOON...THE RIDGE AXIS WILL SHIFT EASTWARD TODAY AS A
SURFACE TROUGH AND ITS COINCIDENT COLD FRONT APPROACH FROM THE WEST.
UPSTREAM CONVECTION IS ANTICIPATED TO WEAKEN MOSTLY BEFORE REACHING THE
UPPER OHIO VALLEY. THE RAP INDICATES SBCAPE INCREASING TO 500-1000
J/KG WITH LI VALUES DECREASING TO -1 TO -3 BY LATE EVENING. THIS
MAY BE ENOUGH INSTABILITY TO MAINTAIN A FEW STORMS AS THE WEAKENING
CONVECTION CROSSES OHIO. THUS, A SCHC HAS BEEN MOVED UP TO 21Z
ACROSS AREAS WEST OF PITTSBURGH. WARM AIR ADVECTION WILL BE
ONGOING TODAY, ALLOWING FOR 850MB TEMPS TO INCREASE TO 16-17C.
THUS, HIGHS TODAY WILL BE AROUND 5 DEGREES ABOVE NORMAL, WELL INTO
THE MID 80S ACROSS MOST OF THE AREA.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SUNDAY/...
LATEST MODEL RUNS REMAIN IN GENERAL AGREEMENT IN HANDLING THE
APPROACH AND PASSAGE OF AN UPPER TROUGH AND THE ASSOCIATED COLD
FRONT TONIGHT AND FRIDAY.
WARM...MOIST ADVECTION AND INCREASING ASCENT IN ADVANCE OF THAT
SYSTEM SUPPORT SCATTERED PRECIP PROBABILITIES BEGINNING TONIGHT...AND
RESULT IN LIKELY NUMBERS WITH THE PASSAGE OF THE COLD FRONT ON
FRIDAY. ALTHOUGH DEEP LAYER SHEAR VALUES ARE FORECAST TO INCREASE
CONSIDERABLY WITH THE QUICKENING FLOW ALOFT...CURRENT THOUGHTS ARE
THAT TIMING OF THE FRONTAL PASSAGE SHOULD LIMIT INSTABILITY
BUILDUP AND PRECLUDE SEVERE STORMS.
THEREAFTER...HAVE PERSISTED IN THE PREVIOUSLY FORECAST FRIDAY
AFTERNOON AND EVENING POP DIMINISHMENT IN ACCORDANCE WITH THE
EXPECTED EXIT OF THE SYSTEM.
A CLOSED UPPER LOW IS PROGGED TO REMAIN PARKED OVER JAMES BAY
THROUGH THE WEEKEND WITH A BROAD TROUGH HOLDING OVER THE EASTERN CONUS.
THIS PATTERN WILL MAINTAIN SUB NORMAL POST FRONTAL TEMPERATURES AS
SURFACE RIDGING AND DRY ADVECTION YIELD GENERALLY DRY CONDITIONS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
SEASONABLY COOL AND GENERALLY DRY WEATHER IS FORECAST AS A BROAD
UPPER LEVEL TROUGH REMAINS ENTRENCHED OVER THE REGION WITH WEAK
SURFACE RIDGING. KEPT POPS IN THE SLIGHT CHANCE RANGE...BELOW 25
PERCENT THROUGH THE PERIOD.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
CONSIDERING MOSTLY SUNNY SKIES AND MODERATE WINDS ON
WEDNESDAY...SOME LOW LEVEL DRYING SHOULD HAVE OCCURRED...SO DO NOT
ANTICIPATE THAT ANY SITES WOULD HAVE CONDITIONS LOWER THIS MORNING
THAN THEY DID YESTERDAY MORNING. STILL THINK THAT MOST SITES WILL
HAVE A FAIR CHANCE OF DROPPING TO IFR...ALTHOUGH GUIDANCE IS MORE
OPTIMISTIC IN THE MVFR/VFR RANGE. ANY FOG WILL DISSIPATE BY MID
MORNING...WITH VFR CONDITIONS EXPECTED FOR THE REST OF THE TAF
PERIOD.
.OUTLOOK...
MVFR/IFR RESTRICTIONS ARE POSSIBLE FRIDAY IN SHOWERS AND
THUNDERSTORMS WITH THE NEXT COLD FRONT. GENERAL VFR IS ANTICIPATED
UNDER WEEKEND SURFACE HIGH PRESSURE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
334 PM EDT THU AUG 16 2012
.SYNOPSIS...
ISSUED AT 333 PM EDT THU AUG 16 2012
A STRONG COLD FRONT COMING THROUGH SOUTHWEST MICHIGAN THIS EVENING
WILL BRING UNSEASONABLY COOL TEMPERATURES TO THE AREA THROUGH THE WEEKEND.
A SLOW WARMING TREND WILL BEGIN BY TUESDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 333 PM EDT THU AUG 16 2012
THE BIGGEST ISSUE IS WILL MORE CONVECTION DEVELOP BEFORE THE FRONT
COMES THROUGH EARLY THIS EVENING? OTHER THAN THAT A LARGE CLOSED
UPPER LOW OVER SOUTHERN HUDSON BAY WILL FEED UNSEASONABLY COOL
WEATHER INTO THE AREA THROUGH THROUGH THE SHORT TERM.
THE LARGE AREA OF RAIN COOLED AIR FROM THE MORNING SQUALL LINE HAS
CREATED A LARGE POCKET OF COOL AIR AHEAD OF THE SURFACE COLD
FRONT. MIX LAYER CAPES OVER SOUTHWEST LOWER MICHIGAN AT 3 PM WERE
UNDER 300 J/KG. SO EVEN WITH THE 40 TO 60 KNOTS OF DEEP LAYER
SHEAR AND STRONG SURFACE WIND CONVERGENCE ON THE FRONT... LITTLE
HAS DEVELOPED ON THE FRONT AS OF YET. I DO BELIEVE THE AREA SOUTH
AND EAST OF I-69 WILL HAVE TO BE WATCHED EARLY THIS EVENING AS THE
RAP SHOWS MIX LAYER CAPES RISING IN THAT AREA TO 500 J/KG THERE.
STILL NOT ALL THAT GREAT THROUGH. ALSO THE HRRR RUC SHOWS A LINE
DEVELOPING BETWEEN 22Z AND 01Z MOVING EAST AND INCREASING THROUGH
02Z AS IT EXITS THE SE CWA. I REMAIN UNIMPRESSED SO I HAVE ONLY
30-40 PCT POPS INTO EARLY THIS EVENING.
AFTER THAT A HIGH PRESSURE RIDGE BUILDS IN AND THAT SHOULD HELP TO
CLEAR OUT ANY RESIDUAL LOW CLOUDS THAT NOW COVER MOST OF WI
BEHIND THE FRONT BY MID MORNING FRIDAY. THE AIR REMAINS TO DRY FOR
LAKE EFFECT RAIN SHOWERS SO I KEPT THE FORECAST DRY THROUGH
SATURDAY.
WITH LIGHT WINDS AND DRY AIR WE COULD SEE LOWS IN THE 30S NEAR AND
NORTH OF ROUTE 10 SATURDAY MORNING. STILL THE DEW POINTS WILL BE
TO HIGH FOR FROST SO THAT SHOULD NOT BE MUCH OF A PROBLEM.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 333 PM EDT THU AUG 16 2012
COOL WX WILL CONTINUE SUNDAY AND MONDAY BEFORE TEMPS MODERATE TO
NEAR NORMAL TUESDAY THROUGH THURSDAY. THE UPPER LEVEL TROUGH AND
COLD POOL OF AIR ALOFT IN CONJUNCTION WITH SEVERAL SHORTWAVES
ROTATING AROUND THE UPPER LOW AND SOME SUN WILL COMBINE TO PRODUCE
SCATTERED DIURNALLY DRIVEN SHOWERS SUNDAY AND MONDAY (MAINLY DURING
THE AFTERNOON AND EARLY EVENING).
MAX TEMPS SUNDAY AND MONDAY WILL ONLY REACH THE 70 TO 75 DEGREE
RANGE. DRY AND MILDER WX IS ANTICIPATED TUESDAY THROUGH WEDNESDAY
WITH MAX TEMPS BACK NEAR NORMAL IN THE UPPER 70S TO LOWER 80S. THE
NEXT LOW PRESSURE SYSTEM TO IMPACT OUR AREA WILL BRING A CHC OF
SHOWERS AND TSTORMS BY LATE NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY)
ISSUED AT 120 PM EDT THU AUG 16 2012
PRIMARILY MVFR CIGS ARE ANTICIPATED THIS AFTERNOON THROUGH THIS
EVENING WITH EXTENSIVE LOW CLOUD COVER NOTED OFF TO THE WEST. RADAR
TRENDS INDICATE SHOWERS WILL LINGER AT KLAN/KJXN THRU MID AFTN
BEFORE EXITING. THERE IS POTENTIAL FOR A FEW MORE SHOWERS TO DEVELOP
ALONG AND JUST AHEAD OF THE COLD FRONT LATE THIS AFTN/EARLY EVE
MAINLY AT KLAN/KJXN.
CONDITIONS WILL GRADUALLY TRANSITION FROM MAINLY MVFR TO VFR
OVERNIGHT WITH CIGS EXPECTED TO SLOWLY INCREASE TO AROUND 3500-4000
KFT AGL.
&&
.MARINE...
ISSUED AT 333 PM EDT THU AUG 16 2012
ENOUGH WIND AND COLD AIR TO KEEP THE WAVES 3 TO 6 FEET INTO FRIDAY
AFTERNOON SO I WILL CONTINUE OUR BEACH HAZARD EVENT AND SC AS IS.
IT SHOULD BE NOTED THAT THE LUDINGTON BUOY HAD WAVE HEIGHTS AS
HIGH AS 7 FEET THIS MORNING.
&&
.HYDROLOGY...
ISSUED AT 333 PM EDT THU AUG 16 2012
RAINFALL WAS FOR THE MOST PART BETWEEN .3 AND .7 INCHES OF MOST OF
THE WESTERN AND CENTRAL CWA WITH LESSER AMOUNTS TO THE EAST AND
SOUTHEAST. THIS WAS NOT ENOUGH TO CAUSE ANY RIVER RISE ISSUES BUT
SHOULD BE ENOUGH TO MITIGATE DROUGHT ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH FRIDAY AFTERNOON FOR MIZ037-043-
050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT FRIDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
132 PM EDT THU AUG 16 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 559 AM EDT THU AUG 16 2012
MAIN FCST PROBLEMS FOCUS ON COVERAGE OF SHRA/TSRA ALONG COLD FRONT
AS IT MOVES THROUGH CENTRAL/ERN UPR MI THIS MORNING INTO EARLY
AFTERNOON...POSSIBILITY OF LINGERING INSTABILITY SHRA AND LAKE
EFFECT SHRA IN WAKE OF FRONT THIS AFTERNOON INTO EARLY FRIDAY...AND
GOOD POTENTIAL FOR ADVISORY W-NW WINDS OVER THE KEWEENAW PENINSULA
THIS AFTERNOON INTO THIS EVENING AND THEN OVER SHORELINE AREAS OF
ALGER AND LUCE COUNTIES TONIGHT.
WV IMAGERY AND RUC ANALYSIS SHOWS WELL-DEFINED VIGOROUS NEG-TILT
SHORTWAVE TROUGH MOVING THROUGH NRN ONTARIO. AT THE SFC...A COLD
FRONT EXTENDS SOUTH FROM THIS SYSTEM THROUGH WRN UPR MI AND NW WI.
MOISTURE CONVERGENCE AND INSTABILITY ALONG THIS FRONT HAVE SUPPORTED
SCT SHRA/TSRA ALONG THIS FRONT OVER WRN UPR MI AND NOW OVR FAR
SCNTRL UPR MI IN THE PAST HR.
TODAY AND TONIGHT...SHOWERS AND ISOLD TSRA OVER NCNTRL UPR MI HAVE
DISSIPATED OR MOVED NORTH OVER LAKE SUPERIOR IN PAST HR AS
INSTABILITY HAS WEAKENED ALONG/AHEAD OF COLD FRONT. DYNAMICS WITH
ONTARIO SHORTWAVE WILL SUSTAIN SHOWERS OVER ERN LAKE SUPERIOR THIS
MORNING INTO EARLY AFTERNOON. RUC HAS FCST MLCAPES INCREASING TO
200-400 J/KG OVER THE EAST HALF OF FCST AREA LATE THIS MORNING ALONG
COLD FRONT WHICH SHOULD SUSTAIN SCT TO NMRS SHRA/TSRA INTO EARLY
AFTERNOON UNTIL COLD FRONT PASSES EAST. LINGERING WEAK DIURNAL
INSTABILITY IN LOW-LVLS AND STEEP SFC-8H LAPSE RATES AS NOTED ON
NAM/RUC FCST SNDGS COULD SUPPORT SOME ISOLD SHRA INTO THE EARLY
AFTERNOON AS MID-LVL TROUGH MOVES OVERHEAD. SOME SCT LAKE EFFECT
SHRA COULD ALSO DEVELOP THIS AFTERNOON OVER WRN COUNTIES IN CYCLONIC
NW FLOW AS LAKE SFC DELTA-T/S WILL INCREASE NEAR 13-14C AS 8H TEMPS
DROP TO 5-6C OVER WRN LAKE SUPERIOR.
BIGGER CONCERN MAY BE POTENTIAL FOR ADVISORY WINDS OVER THE KEWEENAW
PENINSULA AND SHORELINE AREAS OF ALGER LUCE COUNTIES THIS AFTERNOON
INTO TONIGHT. MODELS PARTICULARLY NAM SUGGEST AN AREA OF PRES RISES
(4-5 MB OVER 6HR PERIOD) COMBINED WITH PASSAGE OF SECONDARY COLD
FRONT AND INCREASING INSTABILITY SHOULD ALLOW 35-40 KT TO MIX TO
SFC. HAVE POSTED WIND ADVISORY OVER THE NRN HOUGHTON-KEWEENAW FOR
THIS AFTERNOON INTO THIS EVENING AND OVER SHORELINE AREAS OF ALGER
AND LUCE COUNTIES TONIGHT.
CONTINUED COLD ADVECTION AS 8H TEMPS DROP TO 3-5C TONIGHT IN
CYCLONIC NW FLOW WILL CONTINUE TO SUPPORT LINGERING LAKE EFFECT RAIN
SHOWERS DOWNWIND OF LAKE SUPERIOR ESPECIALLY OVER ERN COUNTIES WHERE
FETCH WILL BE LONGER ACROSS THE LAKE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 559 AM EDT THU AUG 16 2012
NAM SHOWS A CLOSED 500 MB LOW NEAR JAMES BAY ON FRIDAY AND IT DOES
NOT MOVE MUCH SAT NIGHT. A RIDGE OVER THE WESTERN U.S. SLOWLY MOVES
EAST INTO THE ROCKIES WITH TIME. THERE ARE ALSO NUMEROUS WEAK
SHORTWAVES ROTATING AROUND THE CLOSED 500 MB LOW OVER NE ONTARIO IN
THE DEEP TROUGH THAT IS OVER THE ERN U.S. TIMING THESE WILL BE
DIFFICULT AND THESE WEAK SHORTWAVES COULD KICK OFF SOME
SHOWERS...ESPECIALLY DIURNAL HEATING OF THE DAY SHOWERS. DID NOT
MAKE TOO MANY CHANGES TO THE GOING FORECAST. MADE JUST A FEW
ADJUSTMENTS TO TEMPERATURES HERE AND THERE. SLIGHT CHANCE POPS FOR
LATE FRI NIGHT INTO SATURDAY LOOK GOOD ESPECIALLY OVER THE EASTERN
CWA AS ANOTHER SHORTWAVE LOOKS TO BE MOVING THROUGH.
IN THE EXTENDED...GFS AND ECMWF HAVE A DEEP TROUGH OVER THE EASTERN
HALF OF N.A. WITH A RIDGE IN THE WESTERN HALF 12Z SUN. PATTERN DOES
NOT CHANGE UNTIL TUE WHEN THE RIDGE MOVES INTO THE ROCKIES AND THE
TROUGH OVER THE ERN U.S. STARTS TO HEAD EAST AND DE-AMPLIFY A BIT.
COLDER THAN NORMAL TEMPERATURES WILL BEGIN THE PERIOD WITH A SLOW
WARM-UP THIS PERIOD. WITH TROUGHING IN THE AREA THROUGH
MONDAY...DIURNAL SHOWERS ARE DEFINITELY POSSIBLE. A SHORTWAVE
AFFECTS THE AREA FOR WED AND WILL HAVE SLIGHT CHANCE TO LOW CHANCE
POPS IN. TEMPERATURES WARM BACK TO NEAR NORMAL ON TUE AND WED. WILL
CONTINUE DRY FOR MONDAY NIGHT AND TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 131 PM EDT THU AUG 16 2012
BEHIND A COLD FRONT THAT MOVED THROUGH THIS MORNING...WNW WINDS WILL
ADVECT COOLER AND MOISTER LOW LEVEL AIR INTO THE AREA...RESULTING IN
LOW CLOUDS/MVFR CONDITIONS AND STRENGTHENING WINDS. THE STRONGER
WINDS AOA 35KTS AND BETTER CHANCE FOR UPSLOPE/LAKE EFFECT SHRA WILL
BE AT CMX AND IWD WITH MORE PRONOUNCED UPSLOPE WIND COMPONENTS.
EXPECT THESE LOW CIGS TO SLOWLY LIFT TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 559 AM EDT THU AUG 16 2012
AS A COLD FRONT MOVES THROUGH LAKE SUPERIOR THIS MORNING...EXPECT A
SHARP WIND SHIFT TO THE WEST FOLLOWING THIS FRONTAL PASSAGE. THE
ARRIVAL OF MUCH COOLER AIR IN THE WAKE OF THE FRONT OVER THE WARM
WATERS OF LAKE SUPERIOR WILL ALSO RESULT IN ENHANCED MIXING OVER THE
LAKE WITH W-NW WINDS UP TO 30 KTS AND GALES TO 40 KNOTS OVER MOST OF
LAKE SUPERIOR THIS AFTERNOON THROUGH TONIGHT AND HAVE POSTED A GALE
WARNING FOR THIS. EXPECT THE STRONGER NW WINDS TO SLOWLY SUBSIDE ON
FRI THRU THE WEEKEND AS THE PRES GRADIENT WEAKENS WITH BROAD HIGH
PRESSURE SETTLING OVER THE REGION. THERE IS ALSO AN INCREASED RISK
OF RIP CURRENTS IN MARQUETTE AND ALGER COUNTIES THROUGH FRIDAY WITH
STRONG NORTHWEST WINDS AND HIGH WAVES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MIZ001-003.
WIND ADVISORY FROM 9 PM THIS EVENING TO 8 AM EDT FRIDAY FOR
MIZ006-007.
LAKE SUPERIOR...
GALE WARNING FROM 10 PM THIS EVENING TO 11 AM EDT FRIDAY FOR
LSZ267.
GALE WARNING UNTIL 10 AM EDT FRIDAY FOR LSZ264>266.
GALE WARNING UNTIL 1 AM EDT FRIDAY FOR LSZ263.
GALE WARNING FROM 8 PM THIS EVENING TO 11 AM EDT FRIDAY FOR
LSZ249>251.
GALE WARNING UNTIL MIDNIGHT EDT TONIGHT FOR LSZ242-243.
GALE WARNING UNTIL 8 AM EDT FRIDAY FOR LSZ244-245.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...07
AVIATION...TITUS
MARINE...07
AREA FORECAST DISCUSSION
NWS DULUTH MN
1224 PM CDT THU AUG 16 2012
.AVIATION...
MVFR CIGS AND GUSTY NW WINDS ARE EXPECTED THROUGH THE AFTERNOON
ACROSS NE MINNESOTA AND NW WISCONSIN. THE WINDS AROUND 15 KNOTS WILL
GUST TO 20 TO 30 KNOTS AT TIMES. THERE SHOULD BE GRADUAL LIFTING AND
BREAKING UP OF THE CLOUD COVER THIS AFTERNOON. SOME TERMINALS MAY
RETURN TO LOW END BKN/OVC VFR CIGS MID TO LATE AFTERNOON...BUT
OTHERWISE VFR CONDITIONS SHOULD RETURN EARLY TO MID EVENING. THE NW
WINDS WILL RELAX THIS EVENING AND REMAIN LIGHT OVERNIGHT. THERE MAY
BE SOME GUSTS AROUND 15 KNOTS LATE TOMORROW MORNING WHEN THE NW
WINDS REGAIN SOME STRENGTH.
&&
.PREV DISCUSSION... /ISSUED 1002 AM CDT THU AUG 16 2012/
UPDATE...
EXPANDED COVERAGE OF ISOLATED RAIN SHOWERS THIS MORNING AND EARLY
AFTERNOON FURTHER TO THE SOUTH...AND INCREASED TEMPS 1-2 DEG TO
MATCH WITH CURRENT OBSERVATIONS. OTHERWISE...FORECAST LOOKS ON
TRACK.
PREV DISCUSSION... /ISSUED 634 AM CDT THU AUG 16 2012/
AVIATION...08/16/12Z ISSUANCE...
MVFR OR HIGH-END IFR IN CLOUDS IMPROVING TO MID-RANGE MVFR ABOUT
NOON AND TO VFR CLEAR EARLY THIS EVENING THROUGH TONIGHT.
PREV DISCUSSION... /ISSUED 344 AM CDT THU AUG 16 2012/
SHORT TERM...MSAS SHOWS SFC FRNTL BDRY HAS PUSHED INTO ERN WISC
ZONES EARLY THIS MORNING. PRESSURE IS RISING RAPIDLY BEHIND FRONT
AND GUSTY W/NW WINDS ARE INCREASING. A LARGE CANOPY OF POST
FRONTAL LOW CLOUDS IS OCCURRING WITHIN A DEEP MOIST CIRCULATION
GENERATED BY MID LVL TROF STRETCHING FROM ONTARIO SOUTH TO NRN
IOWA. LATEST WV IMAGERY AND RAP ANALYSIS SHOWS A MID LVL SHORTWAVE
TROF MOVING TOWARDS NWRN MN. BEHIND THIS FEATURE...A SECONDARY
FRONTAL SYSTEM IS INDICATED BY THE 925H THETAE FIELD.
TODAY...SECONDARY SHORTWAVE WILL SWEEP SE QUICKLY THIS MORNING AND
EXIT THE NORTH SHORE OF LAKE SUPERIOR BY MIDDAY. SUFFICIENT MSTR
RESIDES WITHIN THE CYCLONIC FLOW TODAY SO SHOWERS WILL BE OCCURRING
ACROSS THE NRN MN ZONES. A BIT CHALLENGING TO PREDICT WHERE THE
PRECIP/NO PRECIP ZONE WILL LIE EXACTLY. CLOUDS WILL BE PREVALENT
IN MOST AREAS THROUGH 18Z...BEFORE A MORE SERIOUS CLEARING TREND
DEVELOPS. LATEST NAM12 FCST AND BUFKIT PROFILES INDICATE 25-35MPH
GUSTS ARE POSSIBLE TODAY. ALONG THE NORTH SHORE THIS AFTN LOCALIZED
HIGHER WINDS ARE POSSIBLE AS AIR DESCENDS FROM HIGHER ELEVATION OF
COOK/LAKE COUNTY DOWN TO LAKE FRONT. MOST SIGNIFICANT COLD
ADVECTION IN BDRY LYR IS FOCUSED OVER ARROWHEAD SO MAX TEMPS MAY
BE SIGNIFICANTLY LOWER THAN SWRN CWA WHERE MORE NEUTRAL ADVECTION
OCCURS BY AFTN.
TONIGHT/TOMORROW...NO MAJOR CHANGES MADE TO EXISTING FCST EXCEPT
TO LOWER POPS FRIDAY OVER ARROWHEAD. SFC HIGH WILL SLOWLY APPROACH
THE CWA AS DEEP UPPER TROF CRAWLS EAST. INHERITED MIN TEMPS LOOK A
BIT ON THE LOW SIDE CONSIDERING SOME AMOUNT OF MIXING IS IMPLIED
BY THE FCST SFC PRESS GRADIENT AND POTENTIAL FOR FEW MORE CLOUDS
IN NW FLOW ALOFT. CURRENT FCST VALUES ARE ON LOW EDGE OF LATEST
SREF 2M TEMP PLUMES SO WE MAY NEED SOME TWEAK UPWARDS IN LATER
FORECASTS. A MID LVL SHORTWAVE TROF WILL APPROACH THE BORDERLAND
AND THE ARROWHEAD LATE FRIDAY. MDL CONSENSUS IS THAT ANY PRECIP
WILL BE SLOW TO ARRIVE.
LONG TERM...FRIDAY NIGHT THROUGH THURSDAY...
SHORT WAVES ROTATING AROUND THE JAMES BAY UPPER TROUGH WILL PROVOKE
A FEW MOSTLY AFTERNOON AND EVENING SHOWERS OR THUNDERSTORMS ACROSS
THE AREA THROUGH THE COMING WEEKEND. A MORE ZONAL FLOW WILL DRY OUR
AREA OUT MONDAY AND TUESDAY. AFTERNOON TEMPERATURES AROUND 70 THIS
WEEKEND WILL WARM TO THE MID OR UPPER 70S MONDAY AND GET INTO THE
80S TUESDAY. A COLD FRONT FROM CENTRAL CANADA AND A DIGGING TROUGH
ALOFT WILL BRING SCATTERED THUNDERSTORMS WEDNESDAY AND THURSDAY.
&&
.POINT TEMPS/POPS...
DLH 45 68 49 70 / 0 10 10 20
INL 43 71 44 69 / 10 20 10 10
BRD 45 70 51 73 / 0 0 10 20
HYR 43 68 44 73 / 0 10 10 20
ASX 47 71 47 71 / 10 10 10 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LSZ121-
140>148.
&&
$$
AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1210 PM CDT THU AUG 16 2012
.UPDATE...
ISSUED AT 1051 AM CDT THU AUG 16 2012
COLD FRONT HAS NOW MOVED TO NEAR A EOK-IRK-SZL AT 15Z. MAIN CLUSTER
OF THUNDERSTORMS ARE STAYING NORTH AND NORTHEAST OF THE CWA AHEAD
OF A VORT MAX OVER FAR EASTERN IOWA. STILL EXPECT SOME DEVELOPMENT
FARTHER SOUTH THE NEXT FEW HOURS AS THE RAP IS SHOWING DECENT SURFACE-
850MB MOISTURE CONVERGENCE DEVELOPING ALONG THE FRONT BETWEEN 18-21Z.
LATEST SPC OBJECTIVE ANALYSIS IS SHOWING MIXED LAYER CAPES OF 2000-2500
J/KG SOUTH OF THE FRONT WITH RAP FORECAST SOUNDINGS SHOWING THE CINH
ERODING BY EARLY AFTERNOON. PREDOMINANT CONVECTIVE MODE STILL LOOKS
LIKE IT WILL BE FROM MULTI-CELL STORMS AS BEST DEEP LAYER SHEAR
REMAINS NORTH OF THE AREA.
HAVE TRIMMED BACK LIKELY POPS FROM CENTRAL MISSOURI INTO WEST
CENTRAL ILLINOIS WHERE THE FRONT HAS ALREADY MOVED SOUTH. FARTHER
SOUTH...HAVE MAINTAINED LIKELY POPS AHEAD OF THE FRONT GIVEN THAT
LOW LEVEL CONVERGENCE WILL BE PERSISTENT WITH THE ERODING CINH.
WILL KEEP CHANCE POPS OVER NORTHEAST MISSOURI AND WEST CENTRAL
ILLINOIS THIS AFTERNOON WHICH WILL HAVE WEAK ASCENT FROM THE TAIL
END OF THE MAIN SHORTWAVE TROUGH MOVING EAST THROUGH THE UPPER
MIDWEST.
BRITT
&&
.SHORT TERM...
ISSUED AT 248 AM CDT THU AUG 16 2012
(TODAY AND TONIGHT)
AS OF THIS WRITING...THE CDFNT THAT IS EXPECTED TO BRING TSRA TO
THE REGION TODAY IS JUST NOW REACHING FAR NWRN TIP OF MO. THE
FORECAST WILL LIKELY TAKE ON A NUMBER OF ITERATIONS TODAY AS A
NUMBER OF QUESTIONS REMAIN WITH MDLS OFFERING A WIDE VARIETY OF
SOLNS.
STRONG WAA EVIDENT IN SATELLITE IMAGERY THIS MORNING WITH ACCAS
AND ISOD SHRA ALREADY DEVELOPED IN CNTL IL STRETCHING WWD INTO W
CNTL IL. WHILE THIS IS DEPICTED IN THE NAM...THE NAM OBVIOUSLY
DOES NOT HAVE ENUF OF A CAP IN PLACE GIVEN FORECAST SOUNDINGS AND
PRECIP OUTPUT. THIS STRONG WAA SHUD ALSO HELP TO PUT A CAP IN
PLACE AHEAD OF THE CDFNT PREVENTING ANY CONVECTION UNTIL EITHER
LATE THIS MORNING OR INTO THE AFTERNOON.
IN GENERAL...BELIEVE TSRA WILL BE LIMITED TO NRN COUNTIES LATE
THIS MORNING AS ONGOING TSRA DIMINISH WITH LOSS OF LLJ. SINCE THE
BEST FORCING AND WEAKEST CAP WILL BE ALONG THE FNT...HAVE TIMED
THE HIGHEST POPS TO BE CO-LOCATED WITH THE FNT. THAT SAID...WITH
DEWPOINTS REACHING INTO THE UPPER 60S...IT SHUD NOT TAKE TOO MUCH
HEATING FOR PARCELS TO BECOME UNSTABLE.
AS FOR THE SVR THREAT...MDLS CONTINUE TO PROG K INDEX VALUES
AROUND 40C. THIS WUD NORMALLY SUGGEST TSRA WILL BE TOO WATER LADEN
TO PRODUCE MUCH IN THE WAY OF SVR WX. HOWEVER...MDL MOISTURE
PROFILE MAY BE OVERDONE. EVEN IF TSRA ARE WATER LADEN...STEEP LOW
LEVEL LAPSE RATES WILL POSE A WIND THREAT ACROSS THE REGION. ANY
OUTFLOW BOUNDARY MAY MODIFY THE ENVIRONMENT AND INCREASE SHEAR
ENUF TO SUPPORT LARGE HAIL LATER IN THE DAY. THIS THREAT SHUD
LINGER INTO AT LEAST THE EARLY EVENING.
THE NAM IS NOW THE ONLY MDL SUGGESTING STRONG FRONTOGENESIS THIS
EVENING PRODUCING TSRA BEHIND THE FNT. WHILE THIS WUD GENERALLY
SUGGEST SHRA...PROG SOUNDINGS HAVE ELEVATED PARCELS UNCAPPED WITH
STRONG FORCING AND HIGH CAPE. IT IS DOUBTFUL HOWEVER THAT ANY SVR
TSRA WILL OCCUR BEHIND THE FNT AS EARLIER ACTIVITY WILL GREATLY
MODIFY THE ATMO AS THE FNT MOVES THRU THE REGION.
AS FOR TEMPS...HAVE TRENDED TWD THE WARM SOLNS...ESP S OF THE FNT.
ALSO TRENDED TWD THE COOLER SOLNS TONIGHT BEHIND THE FNT AS SKIES
CLEAR OUT ACROSS NRN PORTIONS OF THE CWA. OVERALL...THIS RESULTS
IN VERY FEW CHANGES TO THE PREV FORECAST.
TILLY
&&
.LONG TERM...
ISSUED AT 338 AM CDT THU AUG 16 2012
(SATURDAY THROUGH WEDNESDAY)
BEHIND THE CDFNT MENTIONED ABOVE...A LARGE SFC RIDGE WILL SETTLE
INTO THE REGION. HAVE KEPT SLIGHT CHANCE POPS FRI MORNING TO
ACCOUNT FOR ANY LINGERING TSRA LEFT OVER FROM TONIGHT BUT BULK OF
THE ACTIVITY IS EXPECTED TO BE S OF THE CWA.
NW FLOW WILL SETTLE OVER THE REGION WHICH PRESENTS A BIG FORECAST
CHALLENGE. ANY SUBTLE S/W MAY BE ENUF TO GENERATE PRECIP. MDLS
STILL IN GENERALLY GOOD AGREEMENT WITH A S/W DROPPING INTO THE
REGION LATE SAT INTO SUN. HOWEVER...WITH MUCH OF THE MO/IL REGION
LACKING MUCH IN THE WAY OF MOISTURE...IT CURRENTLY APPEARS THIS
S/W WILL NOT GENERATE PRECIP FOR THE CWA.
OTHERWISE...FORECAST REMAINS DRY THRU THE PERIOD WITH BELOW
SEASONAL AVERAGE TEMPS. MDLS IN FAIRLY GOOD AGREEMENT THRU TUES
WITH THE AREA REMAINING IN NW FLOW. BEYOND TUES...THE ECMWF/GEM
SUGGEST A SYSTEM REINFORCING THE UPPER TROF WHILE THE GFS SUGGESTS
THE UPPER RIDGE STARTING TO BUILD BACK INTO THE REGION. DUE TO THE
LARGE DIFFERENCES...HAVE TRENDED TWD A BLEND OF GUIDANCE WHICH
RESULTS NEAR CLIMO. WILL MAKE ADJUSTMENTS AS MDLS COME INTO BETTER
AGREEMENT.
TILLY
&&
.AVIATION...
ISSUED AT 1152 AM CDT THU AUG 16 2012
COLD FRONT IS CURRENTLY NEAR A KUIN-KMBY-KDMO LINE. THE WIND IS
HAS JUST SHIFTED BEHIND FROPA AT KUIN...AND SHOULD ALSO SHIFT
FROM SOUTHWEST TO NORTHWEST WITHIN THE NEXT 1-2 HOURS AT KCOU.
THIS SHIFT WILL LIKELY OCCUR AROUND 21Z AT THE ST. LOUIS METRO TAF
SITES. THUNDERSTORMS ARE STILL EXPECTED TO INCREASE IN COVERAGE
AHEAD OF THE FRONT AS ATMOSPHERE BECOMES MORE UNSTABLE...AND HAVE
EXPANDED THE TIMING OF THE TEMPO GROUP FROM 18-21Z FOR -TSRA. NEW
CELL HAS DEVELOPED TO THE NORTHWEST OF KSTL IN THE LAST FEW
MINUTES. EXPECT MAINLY VFR CONDITIONS THIS AFTERNOON WITH TWO
EXCEPTIONS. ONE BEING MVFR OR POSSIBLY IFR CONDITIONS WITH HEAVER
CORES OF RAIN...THE SECOND WITH LOWER CEILINGS MOVING SOUTH OUT OF
IOWA. STILL MAY BE SOME ISOLATED -SHRA LASTING INTO THE
EVENING...SO HAVE MAINTAINED VCSH AT THE ST. LOUIS METRO TAF
SITES. EXPECT VFR CONDITIONS TO PREVAIL THE LAST HALF OF THE TAF
PERIOD.
SPECIFICS FOR KSTL...AS MENTIONED ABOVE...NEW CELL HAS RECENTLY
DEVELOPED JUST NORTHWEST OF THE TERMINAL...SO HAVE STARTED THE
TEMPO GROUP FOR -TSRA AT 18Z AND WILL CONTINUE IT UNTIL 21Z WHEN I
STILL EXPECT FROPA. WILL MAINTAIN MVFR CAT WITH THE TEMPO GROUP.
THERE STILL MAY BE SOME ISOLATED LIGHT -SHRA BEHIND THE FRONT INTO
EARLY EVENING...SO WILL KEEP VCSH FOR NOW. OTHERWISE EXPECT DRY
AND VFR CONDITIONS OVERNIGHT AND FRIDAY.
BRITT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
323 PM MDT THU AUG 16 2012
.DISCUSSION...
DEFINITE INCREASE IN STORM STRENGTH AND COVERAGE TODAY AS EXPECTED
WITH SEVERAL FORCING MECHANISMS IN PLACE OVER THE STATE. CIRA BLENDED
PWAT IMAGERY SHOWING VALUES OF 100-125 PCT OF NORMAL. THE AXIS OF THE
H5 RIDGE IS POSITIONED FROM NORTHERN AZ SOUTHEAST ACROSS WEST CENTRAL
NM. H5 TEMPS OF -6 TO -7C ARE HELPING NOT TO CAP ANY CONVECTION AS
HAS BEEN THE CASE. WINDS ARE ALSO VERY WEAK ABOVE 700MB SO COMBINATION
OF HIGHER MOISTURE...COOLER TEMPS ALOFT...AND GOOD SURFACE HEATING WILL
ALLOW FOR LOCALLY HEAVY RAINFALL THRU THIS EVENING. THE HRRR AND RUC
MODELS INDICATE CONVECTION WILL ORGANIZE INTO THE MIDDLE RIO GRANDE
VALLEY SOUTHEASTWARD SO HAVE RAISED POPS TO HIGH CHANCE AND LIKELY.
DID NOT HAVE HIGH ENOUGH CONFIDENCE TO PLACE LOCALLY HEAVY RAINFALL
WORDING IN FORECAST FOR TONIGHT...AND FOR THAT MATTER THE NEXT FEW
DAYS...AS IT WILL BE HARD TO PINPOINT ANY SPECIFIC AREA FOR ENHANCED
THREAT.
THE H5 RIDGE AXIS WILL CHANGE LITTLE OVER THE NEXT FEW DAYS...SETTING
UP WEAK STEERING FLOW FOR CENTRAL AND WESTERN NM WHILE THE EAST ENJOYS
THE BENEFITS OF NW FLOW ALOFT. LIGHT UPSLOPE FLOW ACROSS THE PLAINS
ONTO THE EAST SLOPES BENEATH NW FLOW WILL BE FAVORABLE FOR POTENTIALLY
SOME OF BEST PRECIP SEEN IN QUITE SOME TIME. ANOTHER BACK DOOR FRONT
SUNDAY WILL JUST ENHANCE MOISTURE AND PRECIP CHANCES AGAIN. RAISED
POPS EVEN MORE TO THE HIGH CHANCE/LIKELY CATEGORY THRU THE WEEKEND.
TEMPS WILL BE MUCH CLOSER TO NORMAL AND EVEN A FEW DEGREES BELOW. GAP
WINDS ARE EXPECTED AGAIN IN THE RIO GRANDE VALLEY SATURDAY EVENING
INTO SUNDAY MORNING.
MODELS REMAIN AT ODDS BEYOND THE WEEKEND WITH HOW MUCH CONDITIONS WILL
DRY OUT. THE GFS HAS THE RIDGE SLIDING EAST AND CENTERING OVER CENTRAL
NM MONDAY THRU MOST OF NEXT WEEK...WHILE THE ECMWF KEEPS THE RIDGE TO
THE WEST AND FORCING MORE BACK DOOR FRONTS INTO THE AREA. GIVEN THE
PATTERN THIS SUMMER WILL BE FAVORING THE ECMWF AT THIS TIME...WHICH
WILL KEEP TEMPS NEAR NORMAL AND PRECIP CHANCES PERHAPS AT CLIMO FOR
LATE AUGUST. GUYER
&&
.FIRE WEATHER...
CRITICAL FIRE WEATHER...NOT EXPECTED THROUGH AT LEAST MIDWEEK NEXT
WEEK.
FCST MODELS REMAIN IN FAIRLY GOOD AGREEMENT ON GENERAL FCST PATTERN
THROUGH THE START TO MIDDLE OF NEXT WEEK. UPPER HIGH CENTER TO
CONTINUE TO MEANDER BACK AND FORTH GENERALLY BETWEEN NV AND AZ. THIS
WILL ALLOW FOR SOME WEAK TO MODERATE LOW LVL MOISTURE REPLENISHMENT
FROM THE E THROUGH S FROM TIME TO TIME WITH COMBINATION OF WESTBOUND
THROUGH NORTHBOUND OUTFLOWS FROM STORM COMPLEXES IN S AND E HALVES
OF THE STATE AS WELL AS CURRENT WEAKENING BACK DOOR FRONT VCNTY OF
RIO GRANDE VALLEY AS OF THIS WRITING AND ANOTHER ONE DUE INTO E AND
PERHAPS CENTRAL NM OVER THE WEEKEND.
SHOWERS AND STORMS THIS EVE AND OVERNIGHT TO BE MOST NUMEROUS...AND
WITH GOOD WETTING FOOTPRINTS...TO E OF THE CONTINENTAL DIVIDE WITH
MOST LIGHTNING OVER WITH BY OR NOT TOO LONGER AFTER MIDNIGHT...
ESPECIALLY HIGHER TERRAIN. GOOD TO EXCELLENT HUMIDITY RECOVERIES
OVERNIGHT.
FOR FRIDAY...ACTIVE CONVECTION EXPECTED ACROSS THE STATE...WITH
WETTING RAINS THE BEST BET AGAIN E OF DIVIDE. MINIMUM HUMIDITIES
INCREASING TO THE HIGH 20S TO THE MID 40S PCT RANGE OVER MUCH OF THE
STATE...WITH SOME HIGH TEENS AND 20S PCT REMAINING OVER THE DRYER
NORTHWEST QUADRANT. AGAIN GOOD TO EXCELLENT HUMIDITY RECOVERY
OVERNIGHT.
SATURDAY WILL BRING WEAK COLD FRONT INTO THE NORTHEAST PLAINS...
PROGRESSING TO THE S AND W LATER IN THE DAY THROUGH SUN AM. WETTING
RAINS MOST LIKELY ALONG AND E THROUGH N OF FRONTAL BOUNDARY. NW
PLATEAU STILL GETTING THE SHORT END OF THE STICK WITH REGARDS TO
CONVECTION AND WETTING RAIN. VERY GOOD TO EXCELLENT RECOVERIES
OVERNIGHT FOR ALL BUT THE NORTHWEST...WHERE RECOVERY WILL DROP BACK
INTO THE GOOD CATEGORY. FOR SUN THROUGH TUE THE UPPER HIGH AND RIDGE
STILL GENERALLY TO W OF NM. PRETTY GOOD CHANCES FOR WETTING RAINS
SUNDAY BUT BEGINNING A BIT OF A DOWNTURN MON AND TUE. AFTN TEMPS
SHOULD WARM A FEW DEGREES MOST AREAS BY MON OR TUE AND THIS WILL
LOWER MIN HUMIDITIES AND LESSEN OVERNIGHT RECOVERIES. 43
&&
.AVIATION...
18Z TAF CYCLE
BACK DOOR COLD FRONT AS OF MIDDAY LOCATED APPROX FROM WESTERN RIO
ARRIBA COUNTY THEN SOUTHWARD JUST TO THE WEST OF THE MIDDLE RIO
GRANDE VALLEY THEN INTO EASTERN SOCORRO COUNTY. THIS FRONT WILL NOT
LIKELY MOVE TOO MUCH FARTHER WEST THROUGH LATE AFTN...BUT SHOULD
MAKE IT TO OR A LITTLE WAYS EITHER SIDE OF THE CONTINENTAL DIVIDE
TONIGHT. THIS PATTERN WILL SET UP SCT TO AT TIMES NUMEROUS SHRA AND
TSRA COVERAGE LATE THIS AFTERNOON INTO TONIGHT. IN TAFS...VCTS SHOWS
MOST LIKELY EXPECTED TIME OF THUNDERSTORM ACTIVITY IN VCNTY OF SAID
AIRPORT. THE LATER VCSH GROUPS INDICATE REDUCED BUT NOT ZERO
LIGHTNING POTENTIAL AND SOME RAINFALL REMAINING IN VCNTY FOR ALL
POINTS. HEAVIER RAINFALL TODAY MAY DROP CIGS AND VSBY TO MVFR IN
HEAVIER TSTMS FOR RELATIVELY BRIEF PERIODS. TSRA DIMINISHING AFTER 4
OR 5Z OTHERWISE...VFR CONDITIONS AT ALL POINTS OVER THE NEXT 24
HOURS. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 68 94 63 93 / 10 10 10 10
DULCE........................... 52 87 51 87 / 20 30 20 20
CUBA............................ 55 87 56 86 / 30 50 30 30
GALLUP.......................... 60 88 58 88 / 20 30 20 10
EL MORRO........................ 56 80 53 80 / 30 40 30 20
GRANTS.......................... 57 83 52 85 / 30 40 30 20
QUEMADO......................... 56 81 56 85 / 40 40 30 30
GLENWOOD........................ 60 88 56 86 / 50 40 40 20
CHAMA........................... 54 80 49 80 / 30 40 20 40
LOS ALAMOS...................... 62 81 58 82 / 40 60 40 60
PECOS........................... 57 77 59 78 / 50 60 40 60
CERRO/QUESTA.................... 57 79 51 80 / 40 50 30 60
RED RIVER....................... 48 72 45 72 / 50 60 30 60
ANGEL FIRE...................... 48 74 46 74 / 50 60 40 60
TAOS............................ 54 83 53 83 / 40 50 30 50
MORA............................ 52 74 56 75 / 50 60 40 60
ESPANOLA........................ 59 87 58 88 / 40 40 30 50
SANTA FE........................ 62 81 59 82 / 50 50 30 60
SANTA FE AIRPORT................ 63 85 61 85 / 40 50 30 50
ALBUQUERQUE FOOTHILLS........... 65 88 65 88 / 50 40 40 40
ALBUQUERQUE HEIGHTS............. 70 90 67 90 / 50 30 40 30
ALBUQUERQUE VALLEY.............. 67 92 63 93 / 50 30 40 30
ALBUQUERQUE WEST MESA........... 69 91 65 92 / 40 30 40 30
LOS LUNAS....................... 66 90 62 91 / 50 30 40 30
RIO RANCHO...................... 69 92 65 92 / 40 40 40 40
SOCORRO......................... 69 94 66 96 / 60 40 50 30
SANDIA PARK/CEDAR CREST......... 61 85 57 85 / 50 60 50 60
TIJERAS......................... 63 88 58 88 / 50 50 40 60
MORIARTY/ESTANCIA............... 60 82 57 82 / 60 60 50 60
CLINES CORNERS.................. 59 81 60 81 / 50 60 50 60
GRAN QUIVIRA.................... 61 83 62 84 / 60 50 50 60
CARRIZOZO....................... 63 86 64 86 / 40 40 50 50
RUIDOSO......................... 57 75 58 77 / 40 50 50 60
CAPULIN......................... 58 80 56 78 / 40 40 40 50
RATON........................... 59 88 60 86 / 40 50 40 50
SPRINGER........................ 59 86 61 86 / 40 50 40 50
LAS VEGAS....................... 57 80 58 81 / 50 60 50 60
CLAYTON......................... 61 87 59 84 / 30 40 50 40
ROY............................. 64 82 64 85 / 40 50 50 50
CONCHAS......................... 68 90 67 92 / 30 50 50 50
SANTA ROSA...................... 66 90 67 93 / 40 50 50 50
TUCUMCARI....................... 68 91 68 93 / 30 50 50 50
CLOVIS.......................... 66 87 69 88 / 30 50 40 40
PORTALES........................ 68 88 70 87 / 30 50 30 40
FORT SUMNER..................... 70 89 69 91 / 30 50 40 40
ROSWELL......................... 71 91 71 89 / 30 30 30 30
PICACHO......................... 64 84 62 83 / 30 40 30 50
ELK............................. 60 79 59 78 / 30 40 30 50
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
GUYER
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
328 PM EDT THU AUG 16 2012
.SYNOPSIS...
A COLD FRONT ACROSS THE WESTERN GREAT LAKES WILL MOVE EAST ACROSS
THE LOCAL AREA TONIGHT. THE FRONT WILL MOVE TO THE EAST COAST
FRIDAY ALLOWING HIGH PRESSURE TO BEGIN BUILDING OVER THE REGION
FROM THE WEST. THE HIGH IS EXPECTED TO LINGER OVER THE REGION
THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE AREA OF SHOWERS MOVING TOWARD NW OH CONTINUES TO BREAK UP BUT
HAVE STARTED TO SEE SOME NEW DEVELOPMENT IN FAR NE OH ALONG A LAKE
BREEZE BOUNDARY. THESE TRENDS WILL LIKELY CONTINUE FOR THE
REMAINDER OF THE AFTERNOON WITH AN INCREASE IN ACTIVITY IN THE
EAST AND A DECREASE IN THE WEST. HRRR AND CONVECTIVE SREF CONTINUE
TO SHOW ANOTHER LINE OF STORMS DEVELOPING JUST TO THE WEST OF THE
AREA TOWARD 00Z AHEAD OF AN APPROACHING COLD FRONT. THIS IS THE
LINE THAT WILL LIKELY BRING PRECIP TO THE ENTIRE AREA OVERNIGHT.
WILL CONTINUE WITH CATAGORICAL PRECIP CHANCES WITH MOST AREAS
SEEING UP TO A HALF INCH OF RAINFALL. THE PRECIP WILL END FROM
WEST TO EAST AFTER MIDNIGHT AS THE FRONT PULLS OUT. THICK CLOUDS
HAVE OVERSPREAD THE AREA AND THE THREAT FOR SEVERE WEATHER APPEARS
MINIMAL. BETTER INSTABILITY REMAINS TO THE SW AND THAT IS WHERE
ANY SEVERE WEATHER WILL LIKELY OCCUR.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
THE COLD FRONT WILL BE GONE BY DAYBREAK AND MOST OF THE PRECIP
ALONG WITH IT. COULD SEE SOME SHOWERS IN THE EAST AND SOUTH
THROUGH MIDDAY BUT AFTER THAT IT SHOULD BE TOO DRY FOR MORE
PRECIP. 850 MB TEMPS WILL DIP TO AROUND PLUS 8 BY FRIDAY EVENING
SO THIS WILL BE A COLD AIRMASS. WILL LIKELY SEE A FAIR AMOUNT OF
LAKE EFFECT STATO CU THROUGH SATURDAY. SOME INDICATION FROM THE
MODELS OF ANOTHER WEAK FRONT APPROACHING FROM THE NORTH LATE
SUNDAY AND SUNDAY NIGHT. WILL GO WITH A VERY SMALL MENTION OF
SHOWERS IN THE FAR NORTH BUT REALLY DON`T THINK THIS WILL BE A BIG
DEAL. TEMPS WILL AVERAGE WELL BELOW NORMAL AND LATER SHIFTS WILL
HAVE TO WATCH FOR POSSIBLE 40S FOR LOWS SUNDAY MORNING. HAVE USED
A BLEND OF GUIDANCE DURING THE PERIOD.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
INITIALLY LONG RANGE PART OF FORECAST SHOULD START OFF COOL AND
SOMEWHAT CLOUD. THE BIG QUESTION IS WHETHER THE UPPER TROF OVER THE
AREA WILL CAUSE ENOUGH FORCING TO PRODUCE A FEW SHRA...ESPECIALLY IN
THE SNOWBELT OR WHETHER SURFACE HIGH PRESSURE WILL KEEP THINGS DRY.
PREFERENCE IS TO CARRY AT LEAST A SLIGHT CHANCE FOR THE NE PART OF
THE AREA MON THEN GO DRY TUE AS THE UPPER TROF WEAKENS AND SHIFT
EAST.
WED LOOKS DRY AS TEMPS WARM BACK TO NORMAL. THE MODELS DIFFER BY THU
SO MUCH GREATER UNCERTAINTY IN OVERALL FORECAST. THUS FORECAST WILL
LARGELY BE INFLUENCED BY BEST COLLABORATION WITH SURROUNDING WFO`S.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
MODELS REMAIN ON TRACK IN MOVING A COLD FRONT ACROSS THE TAF SITES
TONIGHT. PROBLEM IS THAT CURRENT BAND OF CONVECTION WITH THE FRONT
IS AHEAD OF MODEL PROJECTIONS THUS LEADING TO AN ISSUE WITH MODEL
TIMING. WILL USE BLEND OF CURRENT RADAR INFO WITH MODELS TO TIME
TSRA EAST ACROSS THE AREA. EMPHASIS WILL BE ON CURRENT RADAR FOR
WESTERN TAF SITES WITH EMPHASIS GRADUALLY SHIFTING MORE TO MODELS
FOR TAF SITES FURTHER TO THE EAST.
EXPECT SOME FOG TO OCCUR LATER TONIGHT AFTER THE RAIN BUT CLOUD
COVER AND WNW FLOW OF 5 TO 8 KNOTS SHOULD KEEP FOG MOSTLY IN THE
MVFR RANGE. FOG AND CIGS IMPROVE FRI MORNING ALTHOUGH SOME MVFR MAY
LINGER IN THE EAST THROUGH 18Z AS SOME LAKE ENHANCEMENT WILL LIKELY
TAKE PLACE. A FEW SHRA MAY ALSO LINGER AT CAK...YNG AND ERI UNTIL
MIDDAY FRI.
.OUTLOOK...MAINLY VFR SHOULD PREVAIL BUT PATCHES OF LAKE EFFECT MVFR
CLOUDS MAY BE PRESENT SAT INTO MON...ESPECIALLY AROUND THE SNOWBELT.
&&
.MARINE...
COLD FRONT WILL MOVE INTO THE CENTRAL GREAT LAKES TONIGHT. EXPECT TO
SEE SOUTHWEST WINDS TO REMAIN IN THE 10 TO 20 KNOT RANGE. HOWEVER
THE EASTERN HALF OF THE LAKE COULD SEE SLIGHTLY HIGHER FOR A COUPLE
HOURS JUST AHEAD OF THE FRONT AFTER MIDNIGHT. WILL THEN AWAIT THE
WIND SHIFT TO CLEAR LAKE ERIE NEAR OR SHORTLY AFTER SUNRISE.
NORTHWESTERLY WINDS MAY BE JUST STRONG ENOUGH WITH THE LONGER FETCH
TO PROVIDE SMALL CRAFT CONDITIONS FOR THE EASTERN HALF TO TWO THIRDS
OF THE LAKE INTO FRIDAY AFTERNOON. WILL LET THE NEXT SHIFT MONITOR
THIS POTENTIAL OVERNIGHT TO DECIDE IF WE WILL REACH THE CRITERIA.
HIGH PRESSURE WILL THEN CONTROL THE LAKE WITH A LIGHT WEST TO
NORTHWEST WIND EXPECTED THROUGH THE WEEKEND. SOUTHWESTERLY WINDS
SHOULD RETURN BY MONDAY AFTERNOON AND SHOULD PERSIST INTO TUESDAY
AHEAD OF THE NEXT COLD FRONT.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...ADAMS
AVIATION...
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
309 PM EDT THU AUG 16 2012
.SYNOPSIS...
STRONG COLD FRONT CROSSES TOMORROW. WEAK HIGH
PRESSURE OVER WEEKEND...WITH DISTURBANCE ALOFT PASSING SUNDAY.
ANOTHER HIGH PRESSURE BUILDS NEXT WEEK
&&
.NEAR TERM /THROUGH FRIDAY/...
MORNING COMPLEX CONT TO WEAKEN AS IT RUNS IN TO DRY AIR IN MID
LVLS AND AWAY FROM COLD FRONT/UPR SUPPORT. RUC AND RAP DO INDICATE
A SLIGHT MOISTENING ACROSS PERRY/MORGAN 22-00Z WHICH MAY BE ENOUGH
FOR AN ISO SHRA/TSRA AS REMNANTS...AT LEAST ALOFT...MOVE ACROSS E
OH. THUS ELECTED TO CODE UP SCHC ACROSS PERRY DURING
AFOREMENTIONED TIME FRAME.
OTHERWISE WILL BE WAITING FOR APPROACH OF UPR TROF AND ASSOCIATED
SFC FRONT HEADING INTO TOMORROW. LIKED TIMING OF PREV FCST WHICH
IS IN GOOD AGREEMENT WITH NAM. LOOKS LIKE AREA WILL BE DEALING
WITH TWO POSSIBLE BANDS OF PCPN...PREFRONTAL BAND IN THE MORNING
FOLLOWED BY A ROUND OF CONVECTION MORE WITH ACTUAL FRONT. HAVE SFC
FRONT JUST ENTERING SE OH AT 12Z WITH PREFRONTAL BAND HAVING
TRAVERSED THRU SE OH/NE KY INTO CENTRAL WV...AIDED MORE BY DECENT
OMEGA ARND H7 AND LLVL WAA. EXPECT THIS TO FIZZLE OUT AS IT HEADS
INTO MTNS BY MID MORNING. WILL KEEP THUNDER IN GIVEN ELEVATED
INSTABILITY. MEANWHILE FRONT MAY SLOW DOWN BRIEFLY TOMORROW WITH
ANOTHER ORGANIZED BAND OF INITIALLY FRONTAL CONVECTION MOVING
ACROSS THE AREA AFTER A BRIEF BREAK FOLLOWING MORNING CONVECTION.
THIS LOOKS TO PROPAGATE OUT AHEAD OF BOUNDARY IN AFTN AND EXIT
MTNS BY 21Z AS DEEPER MOISTURE IS EXODUS. WILL HANG SOME LOW POPS
BACK A FEW HRS WITH SFC FRONT ONLY CROSSING OH RVR BY SAID TIME.
WILL GO WITH HIGHER NUMBERS TONIGHT WITH BL FLOW INCREASING LATE.
HIGHS TOMORROW TRICKY. WILL LEAN TOWARD LOWER NUMBERS FROM
GUIDANCE.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
COLD FRONT EXPECTED TO BE EXIT THE EASTERN MOUNTAINS AT THE
BEGINNING OF THE PERIOD WITH PCPN DECREASING FROM CHANCE TO SLIGHT
CHANCE THROUGH 12Z SATURDAY. DEWPOINTS WILL LINGER INTO THE LOWER
60S EXTREME NORTHEAST...UPPER TO MID 50S EAST OF THE OH
RIVER...DROPPING TO THE LOW 50S ACROSS SOUTHEAST OH BY SATURDAY
MORNING.
HIGH PRESSURE BUILDS BEHIND THE FRONT WITH DRIER AIR TO PROVIDE
PLENTY OF SUNSHINE SATURDAY. WITH ABUNDANT LINGERING MOISTURE OVER
THE EASTERN MOUNTAINS...KEPT SLIGHT CHANCE FOR AFTERNOON SHOWERS.
WITH THE EXPECTED WIDESPREAD CLEARING SATURDAY AND SUNDAY
NIGHTS...DENSE FOG IS A GOOD BET OVER AREAS THAT RECEIVE RAIN AND
ALONG RIVER VALLEYS DUE TO NEAR CLAM FLOW.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
HIGH PRESSURE STRENGTHENS THROUGH MID WEEK PROVIDING MOSTLY CLEAR
SKIES AND NORMAL TEMPERATURES. HOWEVER...THE GFS SUGGEST UPPER LEVEL
SYNOPTIC LIFT ASSOCIATED WITH AND UPPER LEVEL JET...ALTHOUGH
MOISTURE IS LIMITED PER PWATS AROUND 0.75 INCHES...FEW SHOWERS COULD
DEVELOP ONCE AGAIN OVER THE EASTERN MOUNTAINS SUNDAY AFTERNOON.
OTHERWISE...DRY WEATHER AND PLEASANT TEMPERATURES WILL PREVAIL
THROUGH THE END OF THE WEEK.
SOME WARM AIR ADVECTION NOTICED AT H850 FROM 11C TO 14-16C FROM
THE GFS/ECMWF UNDER WEAK SOUTHERLY FLOW FROM WED THROUGH THE END
OF THE WEEK. THEREFORE...INCREASED TEMPS TO THE MID TO UPPER 80S
SIMILAR TO HPC AND GMOS FROM WEDNESDAY THROUGH END OF THE PERIOD.
USED HPC TEMPS...WITH SOME TWEAKS DAY 5 THROUGH DAY 7.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS PREVAIL INTO MUCH OF THE NIGHT. WITH BL FLOW
INCREASING MVFR/IFR FG SHOULD BE MITIGATED TO MTN VALLEYS AND HAVE
KEKN IN IFR FG BY 06Z BEFORE PERHAPS IMPROVING BY DAWN. OTHERWISE
SOME MID AND HI CLDS INCREASE LATE TONIGHT FROM W TO E WITH
PREFRONTAL CONVECTIVE PCPN MOVING ACROSS SE OH INTO CENTRAL WV BY
12Z. WILL CARRY MVFR VSBY IN SHRA WITH VCTS AT THIS DISTANCE. COLD
FRONT ENTERS SE OH ARND 12Z...TAKING MUCH OF THE DAYLIGHT HRS TO
CROSS OH RVR WITH ANOTHER ROUND OF CONVECTION ASSOCIATED WITH
FRONT PUSHING ACROSS LATE MORNING THRU AFTN WITH LCL IFR
CONDITIONS EXPECTED.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: EXTENT OF FG MAY BE GREATER THAN FCST SHOULD
CLOUDS AND INCREASE IN FLOW IS DELAYED. ARRIVAL OF PRECIPITATION
EARLY FRI MORNING MAY ALSO 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 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z FRIDAY...
IFR POSSIBLE IN THUNDERSTORMS FRI AND IN LOW CLOUDS AND / OR FOG SAT
MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/30
NEAR TERM...30
SHORT TERM...ARJ
LONG TERM...ARJ
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
220 PM EDT THU AUG 16 2012
.SYNOPSIS...
STRONG COLD FRONT CROSSES TOMORROW. WEAK HIGH
PRESSURE OVER WEEKEND...WITH DISTURBANCE ALOFT PASSING SUNDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
MORNING COMPLEX CONT TO WEAKEN AS IT RUNS IN TO DRY AIR IN MID
LVLS AND AWAY FROM COLD FRONT/UPR SUPPORT. RUC AND RAP DO INDICATE
A SLIGHT MOISTENING ACROSS PERRY/MORGAN 22-00Z WHICH MAY BE ENOUGH
FOR AN ISO SHRA/TSRA AS REMNANTS...AT LEAST ALOFT...MOVE ACROSS E
OH. THUS ELECTED TO CODE UP SCHC ACROSS PERRY DURING
AFOREMENTIONED TIME FRAME.
OTHERWISE WILL BE WAITING FOR APPROACH OF UPR TROF AND ASSOCIATED
SFC FRONT HEADING INTO TOMORROW. LIKED TIMING OF PREV FCST WHICH
IS IN GOOD AGREEMENT WITH NAM. LOOKS LIKE AREA WILL BE DEALING
WITH TWO POSSIBLE BANDS OF PCPN...PREFRONTAL BAND IN THE MORNING
FOLLOWED BY A ROUND OF CONVECTION MORE WITH ACTUAL FRONT. HAVE SFC
FRONT JUST ENTERING SE OH AT 12Z WITH PREFRONTAL BAND HAVING
TRAVERSED THRU SE OH/NE KY INTO CENTRAL WV...AIDED MORE BY DECENT
OMEGA ARND H7 AND LLVL WAA. EXPECT THIS TO FIZZLE OUT AS IT HEADS
INTO MTNS BY MID MORNING. WILL KEEP THUNDER IN GIVEN ELEVATED
INSTABILITY. MEANWHILE FRONT MAY SLOW DOWN BRIEFLY TOMORROW WITH
ANOTHER ORGANIZED BAND OF INITIALLY FRONTAL CONVECTION MOVING
ACROSS THE AREA AFTER A BRIEF BREAK FOLLOWING MORNING CONVECTION.
THIS LOOKS TO PROPAGATE OUT AHEAD OF BOUNDARY IN AFTN AND EXIT
MTNS BY 21Z AS DEEPER MOISTURE IS EXODUS. WILL HANG SOME LOW POPS
BACK A FEW HRS WITH SFC FRONT ONLY CROSSING OH RVR BY SAID TIME.
WILL GO WITH HIGHER NUMBERS TONIGHT WITH BL FLOW INCREASING LATE.
HIGHS TOMORROW TRICKY. WILL LEAN TOWARD LOWER NUMBERS FROM
GUIDANCE.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
THE 00Z NAM WAS THE SLOWEST WITH THE FRONTAL DEEP MOISTURE...THE GFS
APPEARS TO THE THE QUICKEST. THE 12Z ECMWF WAS A NICE COMPROMISE.
ALL MODELS SHOW THE RIGHT REAR OF A 250 MB JET MAX HELPING THE
SYNOPTIC FORCING CENTERED ON 18Z FRIDAY. WITH THAT IN MIND...LIKE
HPC DAY 2 QPF GOING WETTER...AND WETTER THAN THE 00Z GFS.
BASING THE FORECAST ON THE FRONT NOT PASSING CRW UNTIL ABOUT 00Z
SATURDAY. SO WAS A BIT SLOWER DRYING OUT/LOWERING POPS/IN OUR
SOUTHERN COAL FIELDS AND SOUTHERN MOUNTAINS SATURDAY EVENING.
HARD TO GET ANY GOOD HANDLE ON AMOUNT OF BREAKS IN THE CLOUDS...AND
THE INCREASE IN INSTABILITY FOR FRIDAY AFTERNOON. BUT SOUTHERN AND
EASTERN COUNTIES HAVE BEST CHANCE ON MORE INSTABILITY. STEERING FLOW
ABOUT 30 KNOTS ACROSS THE NORTH AND 25 KNOTS FURTHER SOUTH.
HOPE ANY CONVECTIVE CLUSTERS DO NOT BEND OVER TO A MORE EAST/WEST
ORIENTATION IN OUR SOUTHERN COUNTIES...AND THUS INCREASE CHANCE
FOR REPETITIVE ACTION...BY LATE FRIDAY AFTERNOON OR EARLY FRIDAY
EVENING.
FIGURING ON SOME LOW CLOUDS...MAYBE FOG SATURDAY MORNING MAINLY
EKN-CRW ON SOUTH...BUT TOO EARLY TO INSERT FOG INTENSITY. LOWERING
DEW POINTS REACH FURTHER SOUTH SATURDAY AFTERNOON.
LIKELY A SHARP CLOUD AND POP GRADIENT FROM SE TO NW SUNDAY MORNING
WITH DISTURBANCE ALOFT...INCREASING THE DEEPER MOISTURE TO OUR SOUTH
AND EAST. DID INCLUDE SOME CHANCE POPS IN OUR MOUNTAINOUS COUNTIES
LEAVING THE WESTERN LOWLANDS DRY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
USED PREEPD THINKING FOR THIS PORTION OF THE FORECAST. REGION
SHOULD BE UNDER THE INFLUENCE OF SURFACE HIGH PRESSURE...WITH AN
UPPER LEVEL TROF EXPECTED TO MOVE EAST ON TUESDAY.
THIS SHOULD RESULT IN MAINLY DRY WEATHER. HOWEVER...WITH UPPER
LEVEL TROF PUSHING EAST...HAVE GONE WITH DIURNAL SLIGHT CHANCE POPS
ACROSS OUR HIGHER ELEVATIONS.
USED HPC TEMPS WITH SOME TWEAKS.
&&
.AVIATION /17Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS PREVAIL INTO MUCH OF THE NIGHT. WITH BL FLOW
INCREASING MVFR/IFR FG SHOULD BE MITIGATED TO MTN VALLEYS AND HAVE
KEKN IN IFR FG BY 06Z BEFORE PERHAPS IMPROVING BY DAWN. OTHERWISE
SOME MID AND HI CLDS INCREASE LATE TONIGHT FROM W TO E WITH
PREFRONTAL CONVECTIVE PCPN MOVING ACROSS SE OH INTO CENTRAL WV BY
12Z. WILL CARRY MVFR VSBY IN SHRA WITH VCTS AT THIS DISTANCE. COLD
FRONT ENTERS SE OH ARND 12Z...TAKING MUCH OF THE DAYLIGHT HRS TO
CROSS OH RVR WITH ANOTHER ROUND OF CONVECTION ASSOCIATED WITH
FRONT PUSHING ACROSS LATE MORNING THRU AFTN WITH LCL IFR
CONDITIONS EXPECTED.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: EXTENT OF FG MAY BE GREATER THAN FCST SHOULD
CLOUDS AND INCREASE IN FLOW IS DELAYED. ARRIVAL OF PRECIPITATION
EARLY FRI MORNING MAY ALSO 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 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z FRIDAY...
IFR POSSIBLE IN THUNDERSTORMS FRI AND IN LOW CLOUDS AND / OR FOG SAT
MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/30
NEAR TERM...30
SHORT TERM...KTB
LONG TERM...JSH
AVIATION...30
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
226 PM CDT THU AUG 16 2012
.SHORT TERM...TONIGHT AND FRIDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW TODAYS COLD
FRONT NOW MOVING ACROSS LAKE MICHIGAN EARLY THIS
AFTERNOON...ATTACHED TO A SURFACE LOW OVER ONTARIO. GUSTY NORTHWEST
WINDS BEHIND THE FRONT ARE BRINGING IN A COOLER AIRMASS...AS WELL AS
A STRATO-CU DECK OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. BOTH DLH
AND MQT RADARS ARE PICKING UP ON WEAK RETURNS IN THIS STRATO-CU AREA
AND EAGLE RIVER REPORTED A LIGHT SHOWER OVER THE PAST HOUR. WILL
KEEP A SHOWER MENTION FOR NORTH-CENTRAL WISCONSIN FOR THE REST OF
THE AFTERNOON. AS THE COLD AND MOIST AIR CONTINUES TO FLOW OVER THE
REGION...SHOWER CHANCES AND CLOUD COVER ARE THE MAIN FORECAST
CONCERNS.
TONIGHT...TODAYS COLD FRONT WILL MOVE EAST OVER THE EASTERN GREAT
LAKES WHILE THE BADGER STATE WILL BE BETWEEN THIS FRONT AND HIGH
PRESSURE OVER THE GREAT PLAINS. BREEZY NORTHWEST WINDS WILL
CONTINUE TO PUSH A WIDESPREAD STRATO-CU DECK ACROSS THE REGION THIS
EVENING. IN ADDITION...DELTA T/S WILL BE INCREASING TO 15C OVER
WESTERN LAKE SUPERIOR WHICH WILL ADD A LAKE EFFECT COMPONENT TO THE
CLOUD COVER OVER NORTH-CENTRAL WISCONSIN. AS A RESULT...KEPT A
CHANCE OF SHOWERS ACROSS THE NORTH THROUGH 12Z. DRIER LOW LEVEL AIR
FINALLY ARRIVES AFTER MIDNIGHT WHICH WILL ERODE THE CLOUD COVER
INCLUDING THE LAKE EFFECT BANDS. BUT LAKE EFFECT BANDS SHOULD TAKE
LONGER TO ERODE...SO KEPT MOSTLY CLOUDY CONDITIONS IN THE FORECAST
THROUGH THE NIGHT OVER NORTH-CENTRAL WISCONSIN...WHILE GOING MOSTLY
CLEAR NEARLY EVERYWHERE ELSE. BL WINDS LOOK BEEFY ENOUGH TO PREVENT
DECOUPLING...SO WENT WITH LOWS IN THE MID 40S NORTH TO LOWER 50S
NEAR LAKE MICHIGAN.
FRIDAY...CANADIAN HIGH PRESSURE WILL BE BUILDING EAST ACROSS THE
STATE OF WISCONSIN THROUGH THE DAY. PLENTY OF DRY AIR PRESENT ON
PROGGED SOUNDINGS...BUT FLOW REMAINS OUT OF THE NORTHWEST OFF OF
LAKE SUPERIOR AND THINK THIS WILL INCREASE LOW LEVEL MOISTURE MORE
THAN THE MODELS ARE SHOWING. SO LIKE THE IDEA OF THE PREVIOUS SHIFT
WHICH PORTRAY DIURNAL CU BUILD-UP BY LATE IN THE MORNING. BUT ONCE
MIXING IS ABLE TO TAP INTO THE DRIER AIR ALOFT...SHOULD SEE THE CU
DISSIPATE FAIRLY QUICKLY IN THE AFTERNOON. REMAINING COOL AND
TURNING CONSIDERABLY LESS HUMID WITH HIGHS IN THE MID 60S NORTH TO
LOW 70S SOUTH.
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY.
NUMEROUS PERIODS OF SLIGHT CHC POPS IN THE EXTENDED DUE TO
CONTINUED MODEL DISCREPANCIES ON TIMING AND COVERAGE OF SHOWER
ACTIVITY ACROSS WISCONSIN.
...FRIDAY NIGHT THROUGH SUNDAY...
LARGE SCALE UPPER LEVEL TROUGH STALLS OVER THE EASTERN CONUS FOR
THE BEGINNING PART OF THE EXTENDED WITH SHORTWAVE ENERGY SWINGING
THROUGH THE MEAN FLOW INTO WI. MODELS CONTINUE TO HAVE TROUBLE
HANDLING THESE PIECES OF ENERGY. AGREEMENT THAT FRIDAY NIGHT WILL
REMAIN DRY WITH MANY MODELS TRENDING DOWN IN THE AMOUNT OF CLOUDS
THAT WILL FILTER INTO NORTHERN WISCONSIN OVERNIGHT. STILL THINK
THERE WILL BE ENOUGH CLOUDINESS TO KEEP OVERNIGHT TEMPS ABOVE
FROST CRITERIA...BUT WILL CONTINUE TO MONITOR SITUATION IN CASE
DECREASING CLOUD TREND CONTINUES.
A WEAK SFC FRONT WILL SLIP SOUTH THROUGH WI SATURDAY AS A 500MB
SHORTWAVE MOVES INTO THE GREAT LAKES REGION. THERE IS STILL
DISAGREEMENT BETWEEN MODELS ON HOW QUICKLY THE 500MB SHORTWAVE
DIGS INTO IL...WITH THE ECMWF BEING THE SLOWEST AND THE THE GFS
BEING THE FASTEST. GFS IS THE OUTLIER AND HAS WIDESPREAD PRECIP
BREAKING OUT BY 18Z SAT. HOWEVER... IT IS THE OUTLIER AND MODEL
CONSENSUS KEEPS PRECIP CONFINED TO NORTHERN WISCONSIN. THEREFORE
KEPT SOUTHERN PORTIONS OF THE CWA DRY WITH CHC IN NORTHERN WI.
MODELS DISAGREE FURTHER ON PRECIP CHANCES SATURDAY NIGHT. SOME
MODELS CONTINUE SHOWERS THROUGH 09Z SUN IN CENTRAL WI AND THE FOX
VALLEY...WHILE OTHERS SHUT THE PRECIP OFF AFTER SUNSET. GIVEN THE
DIURNALLY DRIVEN NATURE OF THE PRECIP AND THAT THERE IS VERY
LITTLE UPPER LEVEL DYNAMICS/FORCING TO KEEP THE SHOWERS GOING
THROUGH THE NIGHT...WILL DRY THINGS OUT BY 06Z SUNDAY.
SHOWERS SHOULD THEN DEVELOP AGAIN NEAR THE SLOW MOVING SFC FRONT
SUNDAY AFTERNOON. MODELS ARE TRENDING TOWARDS EASTERN WI SEEING
THE BEST CHCS OF SHOWERS SO INCREASED POPS TO CHC OVER THE EAST.
OTHERWISE...CONTINUED WITH THE WIDESPREAD SLIGHT CHC POPS.
...MONDAY NIGHT THROUGH WEDNESDAY...
SHOULD BE DRY MONDAY NIGHT INTO TUESDAY DUE TO A WEAK UPPER RIDGE
PASSING THROUGH WISCONSIN. A MORE SIGNIFICANT SHORT WAVE WILL
RESULT IN AT LEAST A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS
AROUND THE MIDDLE OF THE WEEK.
EXPECT BELOW NORMAL TEMPERATURES THROUGH MONDAY WITH A WARMER
WEATHER TUESDAY AND WEDNESDAY IN SOUTHERLY FLOW AHEAD OF AN
APPROACHING SURFACE SYSTEM OVER THE PLAINS.
&&
.AVIATION...FOR 12Z TAF ISSUANCE. LARGE AREA OF MVFR AND LOW-END
VFR CIGS WL DROP SE ACRS THE AREA IN THE WAKE OF THE COLD FRONT.
MVFR CIGS MAY LINGER THROUGHOUT TNGT IN THE N DUE TO COLDER AIR
FLOWING ACRS LAKE SUPERIOR.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/WOLF